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Sample records for intense neutron generator linac

  1. Proton induction linacs as high-intensity neutron sources

    International Nuclear Information System (INIS)

    Keefe, D.; Hoyer, E.

    1981-01-01

    Proton induction linacs are explored as high intensity neutron sources. The induction linac - concept, properties, experience with electrons, and possibilities - and its limitations for accelerating ions are reviewed. A number of proton induction linac designs are examined with the LIACEP program and general conclusions are given. Results suggest that a proton induction accelerator of the lowest voltage, consistent with good neutron flux, is preferred and could well be cost competitive with the usual rf linac/storage ring designs. (orig.)

  2. The intense neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, W B

    1966-07-01

    The presentation discusses both the economic and research contexts that would be served by producing neutrons in gram quantities at high intensities by electrical means without uranium-235. The revenue from producing radioisotopes is attractive. The array of techniques introduced by the multipurpose 65 megawatt Intense Neutron Generator project includes liquid metal cooling, superconducting magnets for beam bending and focussing, super-conductors for low-loss high-power radiofrequency systems, efficient devices for producing radiofrequency power, plasma physics developments for producing and accelerating hydrogen, ions at high intensity that are still far out from established practice, a multimegawatt high voltage D.C. generating machine that could have several applications. The research fields served relate principally to materials science through neutron-phonon and other quantum interactions as well as through neutron diffraction. Nuclear physics is served through {mu}-, {pi}- and K-meson production. Isotope production enters many fields of applied research. (author)

  3. The intense neutron generator

    International Nuclear Information System (INIS)

    Lewis, W.B.

    1966-01-01

    The presentation discusses both the economic and research contexts that would be served by producing neutrons in gram quantities at high intensities by electrical means without uranium-235. The revenue from producing radioisotopes is attractive. The array of techniques introduced by the multipurpose 65 megawatt Intense Neutron Generator project includes liquid metal cooling, superconducting magnets for beam bending and focussing, super-conductors for low-loss high-power radiofrequency systems, efficient devices for producing radiofrequency power, plasma physics developments for producing and accelerating hydrogen, ions at high intensity that are still far out from established practice, a multimegawatt high voltage D.C. generating machine that could have several applications. The research fields served relate principally to materials science through neutron-phonon and other quantum interactions as well as through neutron diffraction. Nuclear physics is served through μ-, π- and K-meson production. Isotope production enters many fields of applied research. (author)

  4. A deuteron linac for a high-intensity neutron source

    International Nuclear Information System (INIS)

    Staples, J.; Clark, D.; Grunder, H.; Lancaster, H.; Main, R.; Selph, F.; Smith, L.; Voelker, F.; Yourd, R.

    1976-01-01

    The preliminary design of an accelerator suitable to meet the flux and neutron energy requirements of a CTR materials test facility is presented. The specifications of such a facility call for a neutron flux of 10 14 n/cm 2 -sec distributed over an area of about 10 2 cm 2 with a neutron spectrum similar to that anticipated from a fusion reactor. A 30 MeV deuteron linac producing a CW beam of 125 mA, upgradable to 40 MeV at 250 mA at a later date, would produce the relatively broad spectrum of neutrons at the required intensity. Attention to the low-energy beam intercept on the drift tubes and diffusive losses producing neutrons and attendant activation problems are discussed

  5. Spectral fluence of neutrons generated by radiotherapeutic Linacs

    International Nuclear Information System (INIS)

    Kralik, Miloslav; Solc, Jaroslav; Smoldasova, Jana; Vondracek, Vladimir; Farkasova, Estera; Ticha, Ivana

    2015-01-01

    Spectral fluences of neutrons generated in the heads of the radiotherapeutic linacs Varian Clinac 2100 C/D and Siemens ARTISTE were measured by means of the Bonner spheres spectrometer whose active detector of thermal neutrons was replaced by an activation detector, i.e. a tablet made of pure manganese. Measurements with different collimator settings reveal an interesting dependence of neutron fluence on the area defined by the collimator jaws. The determined neutron spectral fluences were used to derive ambient dose equivalent rate along the treatment coach. To clarify at which components of the linac neutrons are mainly created, the measurements were complemented with MCNPX calculations based on a realistic model of the Varian Clinac. (authors)

  6. Linac design study for an intense neutron-source driver

    International Nuclear Information System (INIS)

    Lynch, M.T.; Browman, A.; DeHaven, R.; Jameson, R.; Jason, A.; Neuschaefer, G.; Tallerico, P.; Regan, A.

    1993-01-01

    The 1-MW spallation-neutron source under design study at Los Alamos is driven by a linac-compressor-ring scheme that utilizes a large portion of the existing Los Alamos Meson Physics Facility (LAMPF) linac, as well as the facility infrastructure. The project is referred to as the National Center for Neutron Research (NCNR). A second phase of the proposal will upgrade the driver power to 5 MW. A description of the 1-MW scheme is given in this paper. In addition, the upgrade path to the substantial increase of beam power required for the 5 MW scenario is discussed

  7. The Canadian intense neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Tunnicliffe, P R

    1967-07-01

    Atomic Energy of Canada Ltd. has proposed construction of an Intense Neutron-Generator. The generator would produce uniquely-intense beams of thermal neutrons for solid-state and low-energy nuclear studies and would yield significant quantities of radioisotopes of both research and commercial value; it would also produce copious sources of mesons and energetic nucleons for use in intermediate-energy nuclear physics and in nuclear-structure studies. The primary neutron source of 10{sup 19}/sec would be generated by bombarding a heavy-element target with a continuous beam of 65 mA of 1 GeV protons. The target of circulating and cooled Pb-Bi eutectic would be surrounded by a tank of heavy water moderator yielding a maximum useful flux of 10{sup 16} thermal neutrons/cm{sup 2}/sec in the region where neutron beams can be extracted. This high-energy spallation process for producing neutrons is nearly four times more efficient in producing neutrons per unit of thermal energy released in the neutron source compared with a fission reactor. Nevertheless, if energy costs for producing the 65 MW proton beam are to be within reason, the machine producing the beam must be efficient. A D.C. machine is in principle ideal but practical achievement of 1 GV is not likely within the time desired. An accelerator where the protons gain energy from radio-frequency fields is the most likely prospect. We have selected a linear accelerator as our reference design and detailed theoretical and experimental studies are in progress. The machine is based on the Los Alamos Meson Physics Facility design reoptimized for continuous rather than pulsed operation. It is approximately one mile long and is expected to achieve nearly 50 percent overall efficiency. There are two major portions, an 'Alvarez' Section operating at 200 MHz accelerating the beam to about 150 MeV, followed by a 'Waveguide' section operating at 800 MHz. Protons are initially injected by an 0.75 MV D.C. accelerator. The Alvarez

  8. Experimental characterization of the neutron spectra generated by a high-energy clinical LINAC

    Energy Technology Data Exchange (ETDEWEB)

    Amgarou, K., E-mail: khalil.amgarou@uab.e [Institut de Radioprotection et de Surete Nucleaire (IRSN), Laboratoire de Metrologie et de Dosimetrie des Neutrons, F-13115 Saint Paul-Lez-Durance (France); Lacoste, V.; Martin, A. [Institut de Radioprotection et de Surete Nucleaire (IRSN), Laboratoire de Metrologie et de Dosimetrie des Neutrons, F-13115 Saint Paul-Lez-Durance (France)

    2011-02-11

    The production of unwanted neutrons by electron linear accelerators (LINACs) has attracted a special attention since the early 50s. The renewed interest in this topic during the last years is due mainly to the increased use of such machines in radiotherapy. Specially, in most of developing countries where many old teletherapy irradiators, based on {sup 60}Co and {sup 137}Cs radioactive sources, are being replaced with new LINAC units. The main objective of this work is to report the results of an experimental characterization of the neutron spectra generated by a high-energy clinical LINAC. Measurements were carried out, considering four irradiation configurations, by means of our recently developed passive Bonner sphere spectrometer (BSS) using pure gold activation foils as central detectors. This system offers the possibility to measure neutrons over a wide energy range (from thermal up to a few MeV) at pulsed, intense and complex mixed n-{gamma} fields. A two-step unfolding method that combines the NUBAY and MAXED codes was applied to derive the final neutron spectra as well as their associated integral quantities (in terms of total neutron fluence and ambient dose equivalent rates) and fluence-averaged energies.

  9. The intense neutron generator study

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, W B

    1966-07-01

    The study has confirmed that a beam of 65 mA of protons at 1000 MeV, striking a molten lead-bismuth target surrounded by heavy water moderator, would give the desired flux of 10{sup 16} thermal neutrons per cm{sup 2} per second to provide intense beams of neutrons and also to produce radioisotopes. The proton beam passing through a thin auxiliary target would also produce beams of mesons. The design and construction of the ion source, injector, accelerator, target and auxiliaries present challenging technical problems. Moreover, continued development for improved life and economy promises to be rewarding. The high neutron intensity is sought for research in solid and liquid state physics and also for nuclear physics. Participation by universities and industry, both in development and use, is expected to be extensive. (author)

  10. The intense neutron generator study

    International Nuclear Information System (INIS)

    Lewis, W.B.

    1966-01-01

    The study has confirmed that a beam of 65 mA of protons at 1000 MeV, striking a molten lead-bismuth target surrounded by heavy water moderator, would give the desired flux of 10 16 thermal neutrons per cm 2 per second to provide intense beams of neutrons and also to produce radioisotopes. The proton beam passing through a thin auxiliary target would also produce beams of mesons. The design and construction of the ion source, injector, accelerator, target and auxiliaries present challenging technical problems. Moreover, continued development for improved life and economy promises to be rewarding. The high neutron intensity is sought for research in solid and liquid state physics and also for nuclear physics. Participation by universities and industry, both in development and use, is expected to be extensive. (author)

  11. Moderator/collimator for a proton/deuteron linac to produce a high-intensity, high-quality thermal neutron beam for neutron radiography

    International Nuclear Information System (INIS)

    Singleterry, R.C. Jr.; Imel, G.R.; McMichael, G.E.

    1995-01-01

    Reactor based high resolution neutron radiography facilities are able to deliver a well-collimated (L/D ≥100) thermal flux of 10 6 n/cm 2 ·sec to an image plane. This is well in excess of that achievable with the present accelerator based systems such as sealed tube D-T sources, Van der Graaff's, small cyclotrons, or low duty factor linacs. However, continuous wave linacs can accelerate tens of milliamperes of protons to 2.5 to 4 MeV. The MCNP code has been used to analyze target/moderator configurations that could be used with Argonne's Continuous Wave Linac (ACWL). These analyses have shown that ACWL could be modified to generate a neutron beam that has a high intensity and is of high quality

  12. Study of neutron fields around an intense neutron generator.

    Science.gov (United States)

    Kicka, L; Machrafi, R; Miller, A

    2017-12-01

    Neutron fields in the vicinity of the newly built neutron facility, at the University of Ontario Institute of Technology (UOIT), have been investigated in a series of Monte Carlo simulations and measurements. The facility hosts a P-385 neutron generator based on a deuterium-deuterium fusion reaction. The neutron fluence at different locations around the neutron generator facility has been simulated using MCNPX 2.7E Monte Carlo particle transport program. To characterize neutron fields, three neutron sources were modeled with distributions corresponding to different incident deuteron energies of 90kV, 110kV, and 130kV. Measurements have been carried out to determine the dose rate at locations adjacent to the generator using bubble detectors (BDs). The neutron intensity was evaluated and the total dose rates corresponding to different applied acceleration potentials were estimated at various locations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Perspectives of development of linac-driver for the ITEP neutron generator

    International Nuclear Information System (INIS)

    Kozodaev, A.M.; Vengrov, R.M.; Drozdovskij, A.A.; Kolomiets, A.A.; Orlov, Yu.G.; Raskopin, A.M.; Skachkov, V.S.; Shvedov, O.V.

    1999-01-01

    The perspectives of developing the experimental accelerator-driven neutron generator being made in ITEP are discussed. The ITEP ADS neutron generator consists of the target-blanket assembly and the linear proton accelerator Istra-36. It is projected to introduce superconducting sections in the composition of the neutron generator linac-driven. The application of superconducting resonators allows to increase the particle energy up to 53 MeV at the average beam current 500 μA. The variants of raising the average current up to 5 mA by increasing the HF-system power are considered. The application of magnetohard materials permits to decrease the cost of the bend magnet and its dimensions. To improve the radiation situation it is proposed to use the graphite absorbers of particles [ru

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

    International Nuclear Information System (INIS)

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

    1997-03-01

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

  15. Research possibilities with an intense neutron generator

    International Nuclear Information System (INIS)

    Bartholomew, G.A.

    1966-01-01

    As the title suggests this paper will depart somewhat from the general topic of this session and will be concerned more with applications of accelerators than with accelerators them elves. The particular application of interest at our laboratory concerns the use of a high current intermediate energy proton accelerator as the basis for a versatile intense neutron source. Chalk River's entry into the intermediate energy accelerator field with neutron production as the primary motivation is somewhat unusual. Although neutron production is also being explored by other laboratories interested in intermediate energy accelerators, e.g., Oak Ridge National Laboratory and Los Alamos Scientific Laboratory, it has not been the major motivation. Our initial motivation was in fact the production of thermal neutrons and this interest has remained foremost in our ING program. We are currently writing a proposal for this project. Our target is to have a proton beam in 1973. (author)

  16. Research possibilities with an intense neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, G A

    1966-07-01

    As the title suggests this paper will depart somewhat from the general topic of this session and will be concerned more with applications of accelerators than with accelerators them elves. The particular application of interest at our laboratory concerns the use of a high current intermediate energy proton accelerator as the basis for a versatile intense neutron source. Chalk River's entry into the intermediate energy accelerator field with neutron production as the primary motivation is somewhat unusual. Although neutron production is also being explored by other laboratories interested in intermediate energy accelerators, e.g., Oak Ridge National Laboratory and Los Alamos Scientific Laboratory, it has not been the major motivation. Our initial motivation was in fact the production of thermal neutrons and this interest has remained foremost in our ING program. We are currently writing a proposal for this project. Our target is to have a proton beam in 1973. (author)

  17. High Intensity, Pulsed, D-D Neutron Generator

    International Nuclear Information System (INIS)

    Williams, D.L.; Vainionpaa, J.H.; Jones, G.; Piestrup, M.A.; Gary, C.K.; Harris, J.L.; Fuller, M.J.; Cremer, J.T.; Ludewigt, Bernhard A.; Kwan, J.W.; Reijonen, J.; Leung, K.-N.; Gough, R.A.

    2008-01-01

    Single ion-beam RF-plasma neutron generators are presented as a laboratory source of intense neutrons. The continuous and pulsed operations of such a neutron generator using the deuterium-deuterium fusion reaction are reported. The neutron beam can be pulsed by switching the RF plasma and/or a gate electrode. These generators are actively vacuum pumped so that a continuous supply of deuterium gas is present for the production of ions and neutrons. This contributes to the generator's long life. These single-beam generators are capable of producing up to 1E10 n/s. Previously, Adelphi and LBNL have demonstrated these generators applications in fast neutron radiography, Prompt Gamma Neutron Activation Analysis (PGNAA) and Neutron Activation Analysis (NAA). Together with an inexpensive compact moderator, these high-output neutron generators extend useful applications to home laboratory operations.

  18. The intensive DT neutron generator of TU Dresden

    Science.gov (United States)

    Klix, Axel; DÖring, Toralf; Domula, Alexander; Zuber, Kai

    2018-01-01

    TU Dresden operates an accelerator-based intensive DT neutron generator. Experimental activities comprise investigation into material activation and decay, neutron and photon transport in matter and R&D work on radiation detectors for harsh environments. The intense DT neutron generator is capable to produce a maximum of 1012 n/s. The neutron source is a solid-type water-cooled tritium target based on a titanium matrix on a copper carrier. The neutron yield at a typical deuteron beam current of 1 mA is of the order of 1011 n/s in 4Π. A pneumatic sample transport system is available for short-time irradiations and connected to wo high-purity germanium detector spectrometers for the measurement of induced activities. The overall design of the experimental hall with the neutron generator allows a flexible setup of experiments including the possibility of investigating larger structures and cooled samples or samples at high temperatures.

  19. High intensity proton linac activities at Los Alamos

    International Nuclear Information System (INIS)

    Rusnak, B.; Chan, K.C.; Campbell, B.

    1998-01-01

    High-current proton linear accelerators offer an attractive alternative for generating the intense neutron fluxes needed for transmutations technologies, tritium production and neutron science. To achieve the fluxes required for tritium production, a 100-mA, 1700-MeV cw proton accelerator is being designed that uses superconducting cavities for the high-energy portion of the linac, from 211 to 1,700 MeV. The development work supporting the linac design effort is focused on three areas: superconducting cavity performance for medium-beta cavities at 700 MHz, high power rf coupler development, and cryomodule design. An overview of the progress in these three areas is presented

  20. 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

  1. Proton linacs for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Lennox, A.J.

    1993-08-01

    Recent advances in the ability to deliver boron-containing drugs to brain tumors have generated interest in ∼4 MeV linacs as sources of epithermal neutrons for radiation therapy. In addition, fast neutron therapy facilities have been studying methods to moderate their beams to take advantage of the high cross section for epithermal neutrons on boron-10. This paper describes the technical issues involved in each approach and presents the motivation for undertaking such studies using the Fermilab linac. the problems which must be solved before therapy can begin are outlined. Status of preparatory work and results of preliminary measurements are presented

  2. On scaling and optimization of high-intensity, low-beam-loss RF linacs for neutron source drivers

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1992-01-01

    RF linacs providing cw proton beams of 30--250 mA at 800--1600 MeV, and cw deuteron beams of 100--250 mA at 35--40 MeV, are needed as drivers for factory neutron sources applied to radioactive waste transmutation, advanced energy production, materials testing facilities, and spallation neutron sources. The maintenance goals require very low beam loss along the linac. Optimization of such systems is complex; status of beam dynamics aspects presently being investigated is outlined

  3. The intensive DT neutron generator of TU Dresden

    Directory of Open Access Journals (Sweden)

    Klix Axel

    2018-01-01

    Full Text Available TU Dresden operates an accelerator-based intensive DT neutron generator. Experimental activities comprise investigation into material activation and decay, neutron and photon transport in matter and R&D work on radiation detectors for harsh environments. The intense DT neutron generator is capable to produce a maximum of 1012 n/s. The neutron source is a solid-type water-cooled tritium target based on a titanium matrix on a copper carrier. The neutron yield at a typical deuteron beam current of 1 mA is of the order of 1011 n/s in 4Π. A pneumatic sample transport system is available for short-time irradiations and connected to wo high-purity germanium detector spectrometers for the measurement of induced activities. The overall design of the experimental hall with the neutron generator allows a flexible setup of experiments including the possibility of investigating larger structures and cooled samples or samples at high temperatures.

  4. The intense neutron generator and future factory type ion accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, W B

    1968-07-01

    A neutron factory is likely to sell its product in the form of isotopes. To ay neutron factories are nuclear reactors. Ion accelerators may also produce isotopes by direct interaction and, at high enough energies, mesons and hyperons. The challenge of the electrical production of neutrons goes far beyond the isotope market. It challenges the two popular concepts for long term large scale energy, the fast breeder reactor and controlled thermonuclear fusion. For this use about 4% of nuclear generated power would be applied in a feedback loop generating extra neutrons. Competition rests on operating and processing costs. The Intense Neutron Generator proposal now cancelled would have been full scale for such a use, but much further advance in accelerator engineering is required and anticipated. Perhaps most promising is the application of the ion drag principle in which rings of fast electrons are accelerated along their axis dragging ions with them by electrostatic attraction. Due to the much larger mass of the ions they can acquire much higher energy than the electrons and the process could be efficient. Such accelerators have not yet been made but experimental and theoretical studies are promising. (author)

  5. The intense neutron generator and future factory type ion accelerators

    International Nuclear Information System (INIS)

    Lewis, W.B.

    1968-01-01

    A neutron factory is likely to sell its product in the form of isotopes. To ay neutron factories are nuclear reactors. Ion accelerators may also produce isotopes by direct interaction and, at high enough energies, mesons and hyperons. The challenge of the electrical production of neutrons goes far beyond the isotope market. It challenges the two popular concepts for long term large scale energy, the fast breeder reactor and controlled thermonuclear fusion. For this use about 4% of nuclear generated power would be applied in a feedback loop generating extra neutrons. Competition rests on operating and processing costs. The Intense Neutron Generator proposal now cancelled would have been full scale for such a use, but much further advance in accelerator engineering is required and anticipated. Perhaps most promising is the application of the ion drag principle in which rings of fast electrons are accelerated along their axis dragging ions with them by electrostatic attraction. Due to the much larger mass of the ions they can acquire much higher energy than the electrons and the process could be efficient. Such accelerators have not yet been made but experimental and theoretical studies are promising. (author)

  6. 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

  7. An intense neutron generator based on a proton accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, G A; Milton, J C.D.; Vogt, E W

    1964-07-01

    A study has been made of the demand for a neutron facility with a thermal flux of {>=} 10{sup 16} n cm{sup -2} sec{sup -1} and of possible methods of producing such fluxes with existing or presently developing technology. Experimental projects proposed by neutron users requiring high fluxes call for neutrons of all energies from thermal to 100 MeV with both continuous-wave and pulsed output. Consideration of the heat generated in the source per useful neutron liberated shows that the (p,xn) reaction with 400 1000 MeV bombarding energies and heavy element targets (e.g. bismuth, lead) is capable of greater specific source strength than other possible methods realizable within the time scale. A preliminary parameter optimization carried through for the accelerator currently promising greatest economy (the separated orbit cyclotron or S.O.C.), reveals that a facility delivering a proton beam of about 65 mA at about 1 BeV would satisfy the flux requirement with a neutron cost significantly more favourable than that projected for a high flux reactor. It is suggested that a proton storage ring providing post-acceleration pulsing of the proton beam should be developed for the facility. With this elaboration, and by taking advantage of the intrinsic microscopic pulse structure provided by the radio frequency duty cycle, a very versatile source may be devised capable of producing multiple beams of continuous and pulsed neutrons with a wide range of energies and pulse widths. The source promises to be of great value for high flux irradiations and as a pilot facility for advanced reactor technology. The proposed proton accelerator also constitutes a meson source capable of producing beams of {pi} and {mu} mesons and of neutrinos orders of magnitude more intense than those of any accelerator presently in use. These beams, which can be produced simultaneously with the neutron beams, open vast areas of new research in fundamental nuclear structure, elementary particle physics

  8. An intense neutron generator based on a proton accelerator

    International Nuclear Information System (INIS)

    Bartholomew, G.A.; Milton, J.C.D.; Vogt, E.W.

    1964-01-01

    A study has been made of the demand for a neutron facility with a thermal flux of ≥ 10 16 n cm -2 sec -1 and of possible methods of producing such fluxes with existing or presently developing technology. Experimental projects proposed by neutron users requiring high fluxes call for neutrons of all energies from thermal to 100 MeV with both continuous-wave and pulsed output. Consideration of the heat generated in the source per useful neutron liberated shows that the (p,xn) reaction with 400 1000 MeV bombarding energies and heavy element targets (e.g. bismuth, lead) is capable of greater specific source strength than other possible methods realizable within the time scale. A preliminary parameter optimization carried through for the accelerator currently promising greatest economy (the separated orbit cyclotron or S.O.C.), reveals that a facility delivering a proton beam of about 65 mA at about 1 BeV would satisfy the flux requirement with a neutron cost significantly more favourable than that projected for a high flux reactor. It is suggested that a proton storage ring providing post-acceleration pulsing of the proton beam should be developed for the facility. With this elaboration, and by taking advantage of the intrinsic microscopic pulse structure provided by the radio frequency duty cycle, a very versatile source may be devised capable of producing multiple beams of continuous and pulsed neutrons with a wide range of energies and pulse widths. The source promises to be of great value for high flux irradiations and as a pilot facility for advanced reactor technology. The proposed proton accelerator also constitutes a meson source capable of producing beams of π and μ mesons and of neutrinos orders of magnitude more intense than those of any accelerator presently in use. These beams, which can be produced simultaneously with the neutron beams, open vast areas of new research in fundamental nuclear structure, elementary particle physics, and perhaps also in

  9. The AECL study for an intense neutron - generator (technical details)

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, G A; Tunnicliffe, P R

    1966-07-01

    The AECL study for an intense neutron-generator has been in progress for two years. Recently the scientific and technical details and the conceptual designs were compiled in a report supporting proposals addressed to AECL's Board of Directors for further work. The compilation is being issued in this form to permit further discussion of the technical aspects. However readers are asked to appreciate that it was written primarily for an AECL audience, and specifically that those chapters giving tentative information about costs, the rate of investment and similar items have been omitted or modified, many references have been made to interim internal reports in order to complete the local documentation, but these references do not imply that the reports themselves can be made generally available. (author)

  10. The AECL study for an intense neutron - generator (technical details)

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, G.A.; Tunnicliffe, P.R

    1966-07-01

    The AECL study for an intense neutron-generator has been in progress for two years. Recently the scientific and technical details and the conceptual designs were compiled in a report supporting proposals addressed to AECL's Board of Directors for further work. The compilation is being issued in this form to permit further discussion of the technical aspects. However readers are asked to appreciate that it was written primarily for an AECL audience, and specifically that those chapters giving tentative information about costs, the rate of investment and similar items have been omitted or modified, many references have been made to interim internal reports in order to complete the local documentation, but these references do not imply that the reports themselves can be made generally available. (author)

  11. The AECL study for an intense neutron - generator (technical details)

    International Nuclear Information System (INIS)

    Bartholomew, G.A.; Tunnicliffe, P.R.

    1966-01-01

    The AECL study for an intense neutron-generator has been in progress for two years. Recently the scientific and technical details and the conceptual designs were compiled in a report supporting proposals addressed to AECL's Board of Directors for further work. The compilation is being issued in this form to permit further discussion of the technical aspects. However readers are asked to appreciate that it was written primarily for an AECL audience, and specifically that those chapters giving tentative information about costs, the rate of investment and similar items have been omitted or modified, many references have been made to interim internal reports in order to complete the local documentation, but these references do not imply that the reports themselves can be made generally available. (author)

  12. On the e-linac-based neutron yield

    International Nuclear Information System (INIS)

    Bunatyan, G.G.; Nikolenko, V.G.; Popov, A.B.

    2010-01-01

    We treat neutron generating in high atomic number materials due to the photonuclear reactions induced by the Bremsstrahlung of an electron beam produced by linear electron accelerator (e-linac). The dependence of neutron yield on the electron energy and the irradiated sample size is considered for various sample materials. The calculations are performed without resort to the so-called 'numerical Monte Carlo simulation'. The acquired neutron yields are well correlated with the data asserted in investigations performed at a number of the e-linac-driven neutron sources

  13. Neutron and photon spectra in LINACs

    International Nuclear Information System (INIS)

    Vega-Carrillo, H.R.; Martínez-Ovalle, S.A.; Lallena, A.M.; Mercado, G.A.; Benites-Rengifo, J.L.

    2012-01-01

    A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10 –6 and 1 MeV. Neutron and the Bremsstrahlung spectra show the same features regardless of the linac voltage. - Highlights: ► With MCNPX code realistic models of two LINACs were built. ► Photon and neutron spectra below the flattening filter and at the isocenter were calculated. ► Neutron spectrum at the flattening filter was compared against the Tosi et al. source-term model. ► Tosi et al. model underestimates the neutron contribution below 1 MeV. ► Photon spectra look alike to those published in literature.

  14. Electro neutrons around a 12 MV Linac

    International Nuclear Information System (INIS)

    Vega C, H. R.; Perez L, L. H.

    2012-10-01

    Neutron contamination around Linacs for radiotherapy is a source of undesirable doses for the patient. The main source of these neutrons is the photonuclear reactions occurring in the Linac head and the patient body. Electrons also produce neutrons through (e, en) reactions. This reaction is known as electro disintegration and is carried out by the electron scattering that produce a virtual photon that is absorbed by the scattering nucleus producing the reaction e + A → (A-1) + n + e'. In this work the electron-neutron spectrum to 100 cm from the isocenter of a 12 MV Linac has been measured using a passive Bonner spheres spectrometer in a novel procedure named Planetary mode. (Author)

  15. Application of superconductivity to intense proton linacs

    International Nuclear Information System (INIS)

    Heinrichs, H.

    1996-01-01

    Three examples of proposed superconducting linacs for intense particle beams are presented, and in two cases compared to normal conducting counterparts. Advantages and disadvantages of both types are discussed. Suggestions for future developments are presented. Finally a comparison of estimated operational costs of the normal and the superconducting linac for the ESS is given. (R.P.)

  16. A High Intensity Multi-Purpose D-D Neutron Generator for Nuclear Engineering Laboratories

    International Nuclear Information System (INIS)

    Ka-Ngo Leung; Jasmina L. Vujic; Edward C. Morse; Per F. Peterson

    2005-01-01

    This NEER project involves the design, construction and testing of a low-cost high intensity D-D neutron generator for teaching nuclear engineering students in a laboratory environment without radioisotopes or a nuclear reactor. The neutron generator was designed, fabricated and tested at Lawrence Berkeley National Laboratory (LBNL)

  17. RESONANCE CONTROL FOR THE COUPLED CAVITY LINAC AND DRIFT TUBE LINAC STRUCTURES OF THE SPALLATION NEUTRON SOURCE LINAC USING A CLOSED-LOOP WATER COOLING SYSTEM

    International Nuclear Information System (INIS)

    Bernardin, J.D.; Brown, R.L.

    2001-01-01

    The Spallation Neutron Source (SNS) is a facility being designed for scientific and industrial research and development. SNS will generate and use neutrons as a diagnostic tool for medical purposes, material science, etc. The neutrons will be produced by bombarding a heavy metal target with a high-energy beam of protons, generated and accelerated with a linear particle accelerator, or linac. The low energy end of the linac consists of two room temperature copper structures, the drift tube linac (DTL), and the coupled cavity linac (CCL). Both of these accelerating structures use large amounts of electrical energy to accelerate the protons to an energy of 185 MeV. Approximately 60-80% of the electrical energy is dissipated in the copper structure and must be removed. This is done using specifically designed water cooling passages within the linac's copper structure. Cooling water is supplied to these cooling passages by specially designed resonance control and water cooling systems

  18. Linac design for intense hadron beams

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chuan

    2009-12-14

    Based on the RFQ and H-type DTL structures, this dissertation is dedicated to study the beam dynamics in the presence of significantly strong space-charge effects while accelerating intense hadron beams in the low- and medium-{beta} region. Besides the 5 mA/30 mA, 17 MeV proton injector (RFQ+DTL) and the 125 mA, 40 MeV deuteron DTL of the EUROTRANS and IFMIF facilities, a 200 mA, 700 keV proton RFQ has been also intensively studied for a small-scale but ultra-intense neutron source FRANZ planned at Frankfurt University. The most remarkable properties of the FRANZ RFQ and the IFMIF DTL are the design beam intensities, 200 mA and 125 mA. A new design approach, which can provide a balanced and accelerated beam bunching at low energy, has been developed for intense beams. To design the IFMIF DTL and the injector DTL part of the EUROTRANS driver linac, which have been foreseen as the first real applications of the novel superconducting CH-DTL structure, intensive attempts have been made to fulfill the design goals under the new conditions. For the IFMIF DTL, the preliminary IAP design has been considerably improved with respect to the linac layout as well as the beam dynamics. By reserving sufficient drift spaces for the cryosystem, diagnostic devices, tuner and steerer, introducing SC solenoid lenses and adjusting the accelerating gradients and accordingly other configurations of the cavities, a more realistic, reliable and efficient linac system has been designed. On the other hand, the specifications and positions of the transverse focusing elements as well as the phase- and energy-differences between the bunch-center particle and the synchronous particle at the beginning of the {phi}{sub s}=0 sections have been totally redesigned. For the EUROTRANS injector DTL, in addition to the above-mentioned procedures, extra optimization concepts to coordinate the beam dynamics between two intensities have been applied. In the beam transport simulations for both DTL designs

  19. Linac design for intense hadron beams

    International Nuclear Information System (INIS)

    Zhang, Chuan

    2009-01-01

    Based on the RFQ and H-type DTL structures, this dissertation is dedicated to study the beam dynamics in the presence of significantly strong space-charge effects while accelerating intense hadron beams in the low- and medium-β region. Besides the 5 mA/30 mA, 17 MeV proton injector (RFQ+DTL) and the 125 mA, 40 MeV deuteron DTL of the EUROTRANS and IFMIF facilities, a 200 mA, 700 keV proton RFQ has been also intensively studied for a small-scale but ultra-intense neutron source FRANZ planned at Frankfurt University. The most remarkable properties of the FRANZ RFQ and the IFMIF DTL are the design beam intensities, 200 mA and 125 mA. A new design approach, which can provide a balanced and accelerated beam bunching at low energy, has been developed for intense beams. To design the IFMIF DTL and the injector DTL part of the EUROTRANS driver linac, which have been foreseen as the first real applications of the novel superconducting CH-DTL structure, intensive attempts have been made to fulfill the design goals under the new conditions. For the IFMIF DTL, the preliminary IAP design has been considerably improved with respect to the linac layout as well as the beam dynamics. By reserving sufficient drift spaces for the cryosystem, diagnostic devices, tuner and steerer, introducing SC solenoid lenses and adjusting the accelerating gradients and accordingly other configurations of the cavities, a more realistic, reliable and efficient linac system has been designed. On the other hand, the specifications and positions of the transverse focusing elements as well as the phase- and energy-differences between the bunch-center particle and the synchronous particle at the beginning of the φ s =0 sections have been totally redesigned. For the EUROTRANS injector DTL, in addition to the above-mentioned procedures, extra optimization concepts to coordinate the beam dynamics between two intensities have been applied. In the beam transport simulations for both DTL designs, no beam

  20. Numerical simulations of stripping effects in high-intensity hydrogen ion linacs

    Directory of Open Access Journals (Sweden)

    J.-P. Carneiro

    2009-04-01

    Full Text Available Numerical simulations of H^{-} stripping losses from blackbody radiation, electromagnetic fields, and residual gas have been implemented into the beam dynamics code TRACK. Estimates of the stripping losses along two high-intensity H^{-} linacs are presented: the Spallation Neutron Source linac currently being operated at Oak Ridge National Laboratory and an 8 GeV superconducting linac currently being designed at Fermi National Accelerator Laboratory.

  1. 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

  2. Development of High Intensity D-T fusion NEutron Generator (HINEG)

    Science.gov (United States)

    Wu, Yican; Liu, Chao; Song, Gang; Wang, Yongfeng; Li, Taosheng; Jiang, Jieqiong; Song, Yong; Ji, Xiang

    2017-09-01

    A high intensity D-T fusion neutron generator (HINEG) is keenly needed for the research and development (R&D) of nuclear technology and safety of the advanced nuclear energy system, especially for the radiation protection and shielding. The R&D of HINEG includes two phases: HINEG-I and HINEG-II. HINEG-I is designed to have both the steady beam and pulsed beam. The neutron yield of the steady beam is up to 1012 n/s. The width of pulse neutron beam is less than 1.5 ns. HINEG-I is used for the basic neutronics study, such as measurement of nuclear data, validation of neutronics methods and software, validation of radiation protection and so on. HINEG-II aims to generate a high neutron yield of 1013 n/s neutrons by adopting high speed rotating tritium target system integrated with jet/spray array enhanced cooling techniques, and can further upgrade to obtain neutron yield of 1014 1015n/s by using of accelerators-array in a later stage. HINEG-II can be used for fundamentals research of nuclear technology including mechanism of materials radiation damage and neutronics performance of components, radiation shielding as well as other nuclear technology applications.

  3. Development of High Intensity D-T fusion NEutron Generator (HINEG

    Directory of Open Access Journals (Sweden)

    Wu Yican

    2017-01-01

    Full Text Available A high intensity D-T fusion neutron generator (HINEG is keenly needed for the research and development (R&D of nuclear technology and safety of the advanced nuclear energy system, especially for the radiation protection and shielding. The R&D of HINEG includes two phases: HINEG-I and HINEG-II. HINEG-I is designed to have both the steady beam and pulsed beam. The neutron yield of the steady beam is up to 1012 n/s. The width of pulse neutron beam is less than 1.5 ns. HINEG-I is used for the basic neutronics study, such as measurement of nuclear data, validation of neutronics methods and software, validation of radiation protection and so on. HINEG-II aims to generate a high neutron yield of 1013 n/s neutrons by adopting high speed rotating tritium target system integrated with jet/spray array enhanced cooling techniques, and can further upgrade to obtain neutron yield of 1014~1015n/s by using of accelerators-array in a later stage. HINEG-II can be used for fundamentals research of nuclear technology including mechanism of materials radiation damage and neutronics performance of components, radiation shielding as well as other nuclear technology applications.

  4. Linac-driven spallation-neutron source

    International Nuclear Information System (INIS)

    Jason, A.J.

    1995-01-01

    Strong interest has arisen in accelerator-driven spallation-neutron sources that surpass existing facilities (such as ISIS at Rutherford or LANSCE at Los Alamos) by more than an order of magnitude in beam power delivered to the spallation target. The approach chosen by Los Alamos (as well as the European Spallation Source) provides the full beam energy by acceleration in a linac as opposed to primary acceleration in a synchrotron or other circular device. Two modes of neutron production are visualized for the source. A short-pulse mode produces 1 MW of beam power (at 60 pps) in pulses, of length less than 1 ms, by compression of the linac macropulse through multi-turn injection in an accumulator ring. A long-pulse mode produces a similar beam power with 1-ms-long pulses directly applied to a target. This latter mode rivals the performance of existing reactor facilities to very low neutron energies. Combination with the short-pulse mode addresses virtually all applications

  5. Discussion of superconducting and room-temperature high-intensity ion linacs

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1996-01-01

    The point of view taken in this discussion is that the basic technology base exists in all essential respects for both superconducting or room-temperature rf linac accelerators and associated power and control systems, and thus a project can make a choice between these technologies on overall system considerations. These include performance, cost, availability, flexibility, and upgradability. Large high-intensity neutron source proposals involving light-ion rf linacs in three categories are reviewed in this context. The categories arc cw linacs to high (∼1 GeV) and low (∼40 MeV) output energy, and pulsed linacs to energy ∼1 GeV

  6. Novel design concepts for generating intense accelerator based beams of mono-energetic fast neutrons

    International Nuclear Information System (INIS)

    Franklyn, C.B.; Govender, K.; Guzek, J.; Beer, A. de; Tapper, U.A.S.

    2001-01-01

    Full text: Successful application of neutron techniques in research, medicine and industry depends on the availability of suitable neutron sources. This is particularly important for techniques that require mono-energetic fast neutrons with well defined energy spread. There are a limited number of nuclear reactions available for neutron production and often the reaction yield is low, particularly for thin targets required for the production of mono-energetic neutron beams. Moreover, desired target materials are often in a gaseous form, such as the reactions D(d,n) 3 He and T(d,n) 3 He, requiring innovative design of targets, with sufficient target pressure and particle beam handling capability. Additional requirements, particularly important in industrial applications, and for research institutions with limited funds, are the cost effectiveness as well as small size, coupled with reliable and continuous operation of the system. Neutron sources based on high-power, compact radio-frequency quadrupole (RFQ) linacs can satisfy these criteria, if used with a suitable target system. This paper discusses the characteristics of a deuteron RFQ linear accelerator system coupled to a high pressure differentially pumped deuterium target. Such a source, provides in excess of 10 10 mono- energetic neutrons per second with minimal slow neutron and gamma-ray contamination, and is utilised for a variety of applications in the field of mineral identification and materials diagnostics. There is also the possibility of utilising a proposed enhanced system for isotope production. The RFQ linear accelerator consists of: 1) Deuterium 25 keV ion source injector; 2) Two close-coupled RFQ resonators, each powered by an rf amplifier supplying up to 300 kW of peak power at 425 MHz; 3) High energy beam transport system consisting of a beam line, a toroid for beam current monitoring, two steering magnets and a quadrupole triplet for beam focusing. Basic technical specifications of the RFQ linac

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

    Science.gov (United States)

    Bowman, Charles D.

    1992-01-01

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

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

    Science.gov (United States)

    Bowman, C.D.

    1992-11-03

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

  9. EXCESS RF POWER REQUIRED FOR RF CONTROL OF THE SPALLATION NEUTRON SOURCE (SNS) LINAC, A PULSED HIGH-INTENSITY SUPERCONDUCTING PROTON ACCELERATOR

    International Nuclear Information System (INIS)

    Lynch, M.; Kwon, S.

    2001-01-01

    A high-intensity proton linac, such as that being planned for the SNS, requires accurate RF control of cavity fields for the entire pulse in order to avoid beam spill. The current design requirement for the SNS is RF field stability within ±0.5% and ±0.5 o [1]. This RF control capability is achieved by the control electronics using the excess RF power to correct disturbances. To minimize the initial capital costs, the RF system is designed with 'just enough' RF power. All the usual disturbances exist, such as beam noise, klystron/HVPS noise, coupler imperfections, transport losses, turn-on and turn-off transients, etc. As a superconducting linac, there are added disturbances of large magnitude, including Lorentz detuning and microphonics. The effects of these disturbances and the power required to correct them are estimated, and the result shows that the highest power systems in the SNS have just enough margin, with little or no excess margin

  10. Proposed Brookhaven accelerator-based neutron generator

    International Nuclear Information System (INIS)

    Grand, P.; Batchelor, K.; Chasman, R.; Rheaume, R.

    1976-01-01

    The d-Li Neutron Source concept, which includes a high-current dueteron linac, is an outgrowth of attempts made to use the BNL, 200-MeV proton linac BLIP facility to do radiation damage studies. It included a 100 mA, 30-MeV deuteron linear accelerator and a fast-flowing liquid lithium jet as the target. The latest design is not very different, except that the current is now 200 mA and the linac energy has been raised to 35 MeV. Both parameters, were changed to optimize the effectiveness of the facility with respect to flux, experimental volume and match to 14 MeV neutron-radiation-damage effects. The proposed Brookhaven Accelerator-based Neutron Generator is described with particular emphasis on the linear accelerator. The proposed facility is a practical and efficient way of producing the intense, high energy neutron beams needed for CTR material studies. The accelerator and liquid-metal technologies are well proven, state-of-the-art technologies. The fact that no new technology is required guarantees the possibility of meeting construction schedules, and more importantly, guarantees a high level of operational reliability

  11. Preinjector for Linac 1, SAMES generator

    CERN Multimedia

    1974-01-01

    For a description of the Linac 1 preinjector, please see first 7403070x. When the original 520 kV Cockcroft-Walton generator broke down in 1973, it was replaced by this much smaller 520 kV SAMES generator, seen here sitting on the floor of the Faraday cage.

  12. First PGAA and NAA experimental results from a compact high intensity D-D neutron generator

    International Nuclear Information System (INIS)

    Reijonen, J.; Leung, K.-N.; Firestone, R.B.; English, J.A.; Perry, D.L.; Smith, A.; Gicquel, F.; Sun, M.; Bandong, B.; Garabedian, G.; Revay, Zs.; Szentmiklosi, L.; Molnar, G.

    2003-01-01

    Various types of neutron generator systems have been designed and tested at the Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory. These generators are based on a D-D fusion reaction. These high power D-D neutron generators can provide neutron fluxes in excess of the current state of the art D-T neutron generators, without the use of pre-loaded targets or radioactive tritium gas. Safe and reliable long-life operations are the typical features of these D-D generators. All of the neutron generators developed in the Plasma and Ion Source Technology Group are utilizing powerful RF-induction discharge to generate the deuterium plasma. One of the advantages of using the RF-induction discharge is it's ability to generate high fraction of atomic ions from molecular gases, and the ability to generate high plasma densities for high extractable ion current from relatively small discharge volume

  13. Laser-energy scaling law for neutrons generated from nano particles Coulomb-exploded by intense femtosecond laser pulses

    International Nuclear Information System (INIS)

    Sakabe, Shuji; Hashida, Masaki

    2015-01-01

    To discuss the feasibility of compact neutron sources the yield of laser produced neutrons is scaled by the laser energy. High-energy ions are generated by Coulomb explosion of clusters through intense femtosecond laser-cluster interactions. The laser energy scaling law of the neutron yield is estimated using the laser intensity scaling law for the energy of ions emitted from clusters Coulomb-exploded by an intense laser pulse. The neutron yield for D (D, n) He shows the potential of compact neutron sources with modern laser technology, and the yield for p (Li, n) Be shows much higher than that for Li (p, n) Be with the assumption of 500 nm-class cluster Coulomb explosion. (author)

  14. Intense fusion neutron sources

    International Nuclear Information System (INIS)

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

    2010-01-01

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 10 15 -10 21 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 10 20 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  15. Intense fusion neutron sources

    Science.gov (United States)

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

    2010-04-01

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

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

    International Nuclear Information System (INIS)

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

    1999-01-01

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

  17. Overview of High Intensity Linac Programs in Europe

    CERN Document Server

    Garoby, R

    2004-01-01

    Recent years have seen a boost in the support by the European Union (EU) of accelerator research in Europe. Provided they coordinate their efforts and define common goals and strategies, laboratories and institutions from the member states can receive a financial support reaching 50% of the total project cost. In the field of High Intensity Linacs, the EU has already supported the EURISOL initiative for nuclear physics, which this year is applying for funding of a Design Study, and the development of linacs for Waste Transmutation. More recently, an initiative for high-energy physics has been approved, which includes a programme for the development of pulsed linac technologies. The coordination and synergy imposed by the EU rules increase the benefit of the allocated resources. Combined with the ongoing internal projects in the partner laboratories, these European initiatives represent a strong effort focussed towards the development of linac technologies. This paper summarises the requests from the various E...

  18. The intense neutron generator INGE-1 at the Technical University of Dresden

    International Nuclear Information System (INIS)

    Bittner, M.; Meisner, A.; Paffrath, E.; Schwiers, H.; Seeliger, D.

    1989-01-01

    The INGE-1 neutron generator developed for intergal 14 MeV neutron experiments is described. The accelerator produces steady d + ion beam in the current range of 1-10 mA with 120-240 keV energies at the target position. The beam is produced with a combined duoplasmatron focalization system on high voltage. A 30 keV beam is accelerated on final energy by a two-gap acceleration tube. The estimations conducted show that the generator maximum strength can reach up to 2x10 12 s -1 at 10 mA beam current and 220 keV energy. 4 refs

  19. Optimized sub thermal neutron source to Linac of CAB

    International Nuclear Information System (INIS)

    Torres, L; Granada, R

    2006-01-01

    We present the results of calculations performed with the code M C N P relative to the neutron field behavior within the moderator for the Bariloche-Linac cold neutron source, using polyethylene as pre moderator and solid mesitylene as moderating material at 90 K.The optimum dimensions for a moderator were obtained, with and without a pre moderator, from the point of view of neutron production and time-width of the neutron pulse.Finally, we adopted for our cold neutron source, a slab pre moderator of P L E at room temperature, and a cylindrical moderator of mesitylene at 90 K with a cooler system of stainless steel with windows of Zircaloy-4 [es

  20. Neutron H*(10) estimation and measurements around 18MV linac.

    Science.gov (United States)

    Cerón Ramírez, Pablo Víctor; Díaz Góngora, José Antonio Irán; Paredes Gutiérrez, Lydia Concepción; Rivera Montalvo, Teodoro; Vega Carrillo, Héctor René

    2016-11-01

    Thermoluminescent dosimetry, analytical techniques and Monte Carlo calculations were used to estimate the dose of neutron radiation in a treatment room with a linear electron accelerator of 18MV. Measurements were carried out through neutron ambient dose monitors which include pairs of thermoluminescent dosimeters TLD 600 ( 6 LiF: Mg, Ti) and TLD 700 ( 7 LiF: Mg, Ti), which were placed inside a paraffin spheres. The measurements has allowed to use NCRP 151 equations, these expressions are useful to find relevant dosimetric quantities. In addition, photoneutrons produced by linac head were calculated through MCNPX code taking into account the geometry and composition of the linac head principal parts. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Preliminary design study and problem definition for intense CW superconducting deuteron ion linac for fusion material study

    International Nuclear Information System (INIS)

    Tanabe, Y.; Kakutani, N.; Ota, T.; Yamaguchi, A.; Takeda, O.; Wachi, Y.; Yamazaki, C.; Morii, Y.

    1997-01-01

    The advantages of superconducting (SC) cavity have been verified for many electron accelerators and the application of SC cavity to high intensity CW ion linacs is currently being considered. These linacs have been required for neutron irradiation tests of materials, transmutation of nuclear waste and so on. An SC linac consisting of SC cavities, SC quadrupole magnets and cryostats, was preliminarily designed to investigate the feasibility of applying to deuteron machine. Beam dynamics analysis was also carried out by using a modified PARMILA code in order to confirm no beam loss. Since radiation damage of superconductors is especially severe for such a machine, data relating to the damage were surveyed and discussed. Moreover, other major facilities such as cryogenic system, radio frequency amplifier and RF control system were considered. Many problems to be solved were defined but no critical issues were found. In consequence, it became clear that SC linac is very attractive and competitive with a room-temperature linac. (orig.)

  2. Tritium breeding experiments in a fusion blanket assembly using a low-intensity neutron generator

    International Nuclear Information System (INIS)

    Dalton, A.W.; Woodley, H.J.; McGregor, B.J.

    1987-01-01

    Experiments have been carried out to determine the accuracy with which tritium production rates (TPRs) can be measured in a fusion blanket assembly of non-spherical geometry by a non-central low intensity D-T neutron source (2x10 10 neutrons per second). The tritium production was determined for samples of lithium carbonate containing high enrichments of 6 Li(96%) and 7 Li(99.9%). The measured data were used to check the accuracy with which the TPRs could be numerically predicted using current nuclear data and calculational methods. The numerical predictions from tritium production from the 7 Li samples agreed within the experimental errors of the measurements, but 6 Li measurements which differ by more than 20 per cent from the predicted values were observed in the lower half of the assembly

  3. Design study on an intense heavy-ion linac system

    International Nuclear Information System (INIS)

    Okamura, M.; Oguri, Y.; Takahashi, Y.; Hattori, T.; Takeda, O.; Satoh, K.; Tanabe, Y.

    1992-01-01

    A four-vane RFQ cavity is designed for an intense heavy-ion linac system. RFQ-vanes with small tip curvatures are applied in order to improve the RF power efficiency. Beam optical and RF parameters are investigated by beams of numerical methods. Using a scale model, the cavity structure is experimentally optimized. (Author) 7 refs., 4 figs

  4. 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.

  5. 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

  6. Beam halo in high-intensity hadron linacs

    Energy Technology Data Exchange (ETDEWEB)

    Gerigk, F

    2006-12-21

    This document aims to cover the most relevant mechanisms for the development of beam halo in high-intensity hadron linacs. The introduction outlines the various applications of high-intensity linacs and it will explain why, in the case of the CERN Superconducting Proton Linac (SPL) study a linac was chosen to provide a high-power beam, rather than a different kind of accelerator. The basic equations, needed for the understanding of halo development are derived and employed to study the effects of initial and distributed mismatch on high-current beams. The basic concepts of the particle-core model, envelope modes, parametric resonances, the free-energy approach, and the idea of core-core resonances are introduced and extended to study beams in realistic linac lattices. The approach taken is to study the behavior of beams not only in simplified theoretical focusing structures but to highlight the beam dynamics in realistic accelerators. All effects which are described and derived with simplified analytic models, are tested in realistic lattices and are thus related to observable effects in linear accelerators. This approach involves the use of high-performance particle tracking codes, which are needed to simulate the behavior of the outermost particles in distributions of up to 100 million macro particles. In the end a set of design rules are established and their impact on the design of a typical high-intensity machine, the CERN SPL, is shown. The examples given in this document refer to two different design evolutions of the SPL study: the first conceptual design report (SPL I) and the second conceptual design report (SPL II). (orig.)

  7. High-voltage pulse generator synchronous with LINAC

    International Nuclear Information System (INIS)

    Muto, M.; Hiratsuka, Yoshio; Niimura, Nobuo

    1974-01-01

    High-voltage pulse generator (H.V. Flip-Flop) No.2, an improved type of No.1, is described, which is used in the structural analysis of transient phenomena in materials through the neutron TOF with a Linac. The method of producing positive and negative high-voltage pulses synchronous with the Linac is identical with that in No.1. However, No.2 has outstanding features as follows: (1) The rise time of output pulses is reduced to 0.3 msec, due to the improvement of switching circuit and the winding of a step-up transformer; (2) The widths of positive and negative pulses are variable up to maximum 8 and 16 frames, respectively (One frame = 10 msec); (3) The distribution of TOF signals from a BF 3 counter to a time analyzer is possible even in the negative voltage duration. The panel is provided with the switches for choosing pulse width and the frame for analysis, as well as the dials for setting positive/negative pulse voltage values and the respective indicating meters. (Mori, K)

  8. Pulsed neutron generator

    International Nuclear Information System (INIS)

    Bespalov, D.F.; Bykovskii, Yu.A.; Vergun, I.I.; Kozlovskii, K.I.; Kozyrev, Yu.P.; Leonov, R.K.; Simagin, B.I.; Tsybin, A.S.; Shikanov, A.Ie.

    1986-03-01

    The paper describes a new device for generating pulsed neutron fields, utilized in nuclear geophysics for carrying out pulsed neutron logging and activation analysis under field conditions. The invention employs a sealed-off neutron tube with a laser ion source which increases neutron yield to the level of 10 neutrons per second or higher. 2 refs., 1 fig

  9. Neutrons leaked from a 45 MeV linac facility

    Energy Technology Data Exchange (ETDEWEB)

    Kitaichi, Masatoshi; Sawamura, Sadashi; Yamada, Takuma; Sawamura, Teruko; Kaneko, Junnichi H. [Hokkaido Univ., Sapporo (Japan); Nojiri, Itiro [Japan Nuclear Cycle Development Institute, Ibaraki (Japan)

    2002-07-01

    Dose evaluation for skyshine from nuclear facilities is an issue in environmental evaluations. Therefore, benchmark data for skyshine and well-investigated codes for skyshine would be useful in the rational evaluations of nuclear facilities. The purpose of this study is to obtain benchmark data of skyshine and to investigate the effect of source spectra and angular distribution on the skyshine process. In this study spatial and time distributions of neutrons leaked from the Hokkaido University 45 MeV electron linac facility were measured and compared with calculations. Neutrons were emitted from the ( ,n) reaction produced by bremsstrahlung radiation in a lead target irradiated with electrons from the linac. The skyshine process of neutrons transported through the facility building to the outside was investigated. The source spectrum of the skyshine process was evaluated using a cylindrical multi-moderator spectrometer and unfolding code, the SAND-II, and the results were compared. Measurements were carried out to a distance of 330 m from the facility. The measured spatial dose distribution was found not to coincide with the calculations. The discrepancy is discussed based on an analysis of the spatial and time distributions, and the energy spectrum which suggests that the source spectrum and the angular distribution assumed in the calculation was not sufficiently similar to simulate the experimental situation. The time distribution introduced in this study appears to be useful in discussions of the skyshine process and its sources.

  10. Neutron generator control system

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  11. INGRID: an intense neutron generator for radiation-induced damage studies in the CTR materials program

    International Nuclear Information System (INIS)

    Saltmarsh, M.J.; Worsham, R.E.

    1976-01-01

    The proposal is broken into the following chapters: (1) the need for a neutron irradiation facility, (2) characteristics of the neutron source, (3) the accelerator, (4) the lithium target source, (5) buildings, utilities, and experimental facilities, and (6) project management, schedule, and costs

  12. A research plan based on high intensity proton accelerator Neutron Science Research Center

    International Nuclear Information System (INIS)

    Mizumoto, Motoharu

    1997-01-01

    A plan called Neutron Science Research Center (NSRC) has been proposed in JAERI. The center is a complex composed of research facilities based on a proton linac with an energy of 1.5GeV and an average current of 10mA. The research facilities will consist of Thermal/Cold Neutron Facility, Neutron Irradiation Facility, Neutron Physics Facility, OMEGA/Nuclear Energy Facility, Spallation RI Beam Facility, Meson/Muon Facility and Medium Energy Experiment Facility, where high intensity proton beam and secondary particle beams such as neutron, pion, muon and unstable radio isotope (RI) beams generated from the proton beam will be utilized for innovative researches in the fields on nuclear engineering and basic sciences. (author)

  13. A research plan based on high intensity proton accelerator Neutron Science Research Center

    Energy Technology Data Exchange (ETDEWEB)

    Mizumoto, Motoharu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    A plan called Neutron Science Research Center (NSRC) has been proposed in JAERI. The center is a complex composed of research facilities based on a proton linac with an energy of 1.5GeV and an average current of 10mA. The research facilities will consist of Thermal/Cold Neutron Facility, Neutron Irradiation Facility, Neutron Physics Facility, OMEGA/Nuclear Energy Facility, Spallation RI Beam Facility, Meson/Muon Facility and Medium Energy Experiment Facility, where high intensity proton beam and secondary particle beams such as neutron, pion, muon and unstable radio isotope (RI) beams generated from the proton beam will be utilized for innovative researches in the fields on nuclear engineering and basic sciences. (author)

  14. Design of a cold-neutron source for the Bariloche LINAC with solid mesitylene as moderator material

    International Nuclear Information System (INIS)

    Torres, Lourdes; Granada, J.R.

    2006-01-01

    We present the results of calculations performed with the code MCNP-4C relative to the neutron-field behaviour within the moderator for the Bariloche-LINAC cold-neutron source, using mesitylene at 89 K as moderating material. Throughout the design calculations we used preliminary nuclear-data libraries for that material that were previously generated and partially validated. The optimum dimensions for a slab and a cylindrical moderator were obtained, with and without a premoderator, from the point of view of neutron production and time-width of the neutron pulse

  15. Finite element thermal study of the Linac4 plasma generator

    International Nuclear Information System (INIS)

    Faircloth, D.; Kronberger, M.; Kuechler, D.; Lettry, J.; Scrivens, R.

    2010-01-01

    The temperature distribution and heat flow at equilibrium of the plasma generator of the rf-powered noncesiated Linac4 H - ion source have been studied with a finite element model. It is shown that the equilibrium temperatures obtained in the Linac4 nominal operation mode (100 kW rf power, 2 Hz repetition rate, and 0.4 ms pulse duration) are within material specifications except for the magnet cage, where a redesign may be necessary. To assess the upgrade of the Linac4 source for operation in the high-power operation mode of the Superconducting Proton Linac (SPL), an extrapolation of the heat load toward 100 kW rf power, 50 Hz repetition rate, and 0.4 ms pulse duration has been performed. The results indicate that a significant improvement of the source cooling is required to allow for operation in the high-power mode of SPL.

  16. Finite element thermal study of the Linac4 plasma generator

    Energy Technology Data Exchange (ETDEWEB)

    Faircloth, D. [STFC, Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX (United Kingdom); Kronberger, M.; Kuechler, D.; Lettry, J.; Scrivens, R. [BE-ABP, Hadron Sources and Linacs, CERN, CH-1211 Geneva (Switzerland)

    2010-02-15

    The temperature distribution and heat flow at equilibrium of the plasma generator of the rf-powered noncesiated Linac4 H{sup -} ion source have been studied with a finite element model. It is shown that the equilibrium temperatures obtained in the Linac4 nominal operation mode (100 kW rf power, 2 Hz repetition rate, and 0.4 ms pulse duration) are within material specifications except for the magnet cage, where a redesign may be necessary. To assess the upgrade of the Linac4 source for operation in the high-power operation mode of the Superconducting Proton Linac (SPL), an extrapolation of the heat load toward 100 kW rf power, 50 Hz repetition rate, and 0.4 ms pulse duration has been performed. The results indicate that a significant improvement of the source cooling is required to allow for operation in the high-power mode of SPL.

  17. Nanosecond neutron generator

    International Nuclear Information System (INIS)

    Lobov, S.I.; Pavlovskaya, N.G.; Pukhov, S.P.

    1991-01-01

    High-voltage nanosecond neutron generator for obtaining neutrons in D-T reaction is described. Yield of 6x10 6 neutron/pulse was generated in a sealed gas-filled diode with a target on the cathode by accelerating pulse voltage of approximately 0.5 MV and length at half-height of 0.5 ns and deuterium pressure of 6x10 -2 Torr. Ways of increasing neutron yield and possibilities of creating generators of nanosecond neutron pulses with great service life are considered

  18. Design study of a medical proton linac for neutron therapy

    International Nuclear Information System (INIS)

    Machida, S.; Raparia, D.

    1988-01-01

    This paper describes a design study which establishes the physical parameters of the low energy beam transport, radiofrequency quadrupole, and linac, using computer programs available at Fermilab. Beam dynamics studies verify that the desired beam parameters can be achieved. The machine described here meets the aforementioned requirements and can be built using existing technology. Also discussed are other technically feasible options which could be attractive to clinicians, though they would complicate the design of the machine and increase construction costs. One of these options would allow the machine to deliver 2.3 MeV protons to produce epithermal neutrons for treating brain tumors. A second option would provide 15 MeV protons for isotope production. 21 refs., 33 figs

  19. Neutron spectrometry and determination of neutron ambient dose equivalents in different LINAC radiotherapy rooms

    International Nuclear Information System (INIS)

    Domingo, C.; Garcia-Fuste, M.J.; Morales, E.; Amgarou, K.; Terron, J.A.; Rosello, J.; Brualla, L.; Nunez, L.; Colmenares, R.; Gomez, F.; Hartmann, G.H.; Sanchez-Doblado, F.; Fernandez, F.

    2010-01-01

    A project has been set up to study the effect on a radiotherapy patient of the neutrons produced around the LINAC accelerator head by photonuclear reactions induced by photons above ∼8 MeV. These neutrons may reach directly the patient, or they may interact with the surrounding materials until they become thermalised, scattering all over the treatment room and affecting the patient as well, contributing to peripheral dose. Spectrometry was performed with a calibrated and validated set of Bonner spheres at a point located at 50 cm from the isocenter, as well as at the place where a digital device for measuring neutrons, based on the upset of SRAM memories induced by thermal neutrons, is located inside the treatment room. Exposures have taken place in six LINAC accelerators with different energies (from 15 to 23 MV) with the aim of relating the spectrometer measurements with the readings of the digital device under various exposure and room geometry conditions. The final purpose of the project is to be able to relate, under any given treatment condition and room geometry, the readings of this digital device to patient neutron effective dose and peripheral dose in organs of interest. This would allow inferring the probability of developing second malignancies as a consequence of the treatment. Results indicate that unit neutron fluence spectra at 50 cm from the isocenter do not depend on accelerator characteristics, while spectra at the place of the digital device are strongly influenced by the treatment room geometry.

  20. Pulsed-neutron production at the Brookhaven 200-MeV linac

    International Nuclear Information System (INIS)

    Ward, T.E.; Alessi, J.; Brennan, J.; Grand, P.; Lankshear, R.; Montemurro, P.; Snead, C.L. Jr.; Tsoupas, N.

    1988-01-01

    The new 750-kV RFQ preinjector and double chopper system capable of selecting single nanosecond micropulses with repetition rates of 0.1--20 MHz has been installed at the Brookhaven 200-MeV proton linac. The micropulse intensity is approximately 1 x 10 9 p/μpulse. Neutron time-of-flight path lengths of 30--100 meter at 0/degree/, 12/degree/, 30/degree/, 45/degree/, 90/degree/ and 135/degree/ are available, as well as a zero degree swinger capable of an angular range of 0--25/degree/. Pulsed neutron beams of monoenergetic (p 7 Li → n 7 Be) and spallation (p 238 U → nx) sources will be discussed in the present paper, as well as detailing the chopped-beam capabilities. 11 refs., 5 figs., 1 tab

  1. Pulsed-neutron production at the Brookhaven 200-MeV linac

    International Nuclear Information System (INIS)

    Ward, T.E.; Alessi, J.; Brennan, J.; Grand, P.; Lankshear, R.; Montemurro, P.; Snead, C.L. Jr.; Tsoupas, N.

    1989-01-01

    The new 750-kV RFQ preinjector and double chopper system capable of selecting single nanosecond micropulses with repetition rates of 0.1 to 20 MHz has been installed at the Brookhaven 200-MeV proton linac. The micropulse intensity is approximately 1 x 10 9 p/μpulse. Neutron time-of-flight path lengths of 30 to 100 meters at 0 degree, 12 degree, 30 degree, 45 degree, 90 degree and 135 degree are available as well as a zero-degree beam swinger capable of an angular range of 0 degree to 25 degree. Pulsed neutron beams of monoenergetic (p 7 Li → n 7 Be) and spallation (p 238 U → nx) sources will be discussed in the present paper as well as detailing the chopped-beam capabilities. 11 refs., 5 figs., 1 tab

  2. Cylindrical neutron generator

    Science.gov (United States)

    Leung, Ka-Ngo [Hercules, CA

    2008-04-22

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  3. Laser neutron generator

    International Nuclear Information System (INIS)

    Anan'in, O.B.; Bespalov, D.F.; Bykovskii, Yu.A.; Kozyrev, Yu.P.; Mints, A.Z.; Riabov, E.V.; Tsybin, A.S.; Cherkasov, Yu.; Shikanov, A.E.

    1986-01-01

    Information is presented concerning devices for producing intense neutrons flows, and may be utilized in nuclear geophysics for carrying out pulsed neutron logging of wells, in studies of the critical characteristics of nuclear reactors, for activation analysis, radiation therapy, defectoscopy, and so on

  4. 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...

  5. A test-type hyper-thermal neutron generator for neutron capture therapy - estimation of neutron energy spectrum by simulation calculations and TOF experiments

    International Nuclear Information System (INIS)

    Sakurai, Yoshinori; Kobayashi, Tooru; Kobayashi, Katsuhei

    1999-01-01

    In order to clarify the irradiation characteristics of hyper-thermal neutrons and the feasibility of a hyper-thermal neutron irradiation field for neutron capture therapy, a 'test-type' hyper-thermal neutron generator was designed and made. Graphite of 6 cm thickness and 21 cm diameter was selected as the high temperature scatterer. The scatterer is heated up to 1200 deg. C maximum using molybdenum heaters. The radiation heat is shielded by reflectors of molybdenum and stainless steel. The temperature is measured using three R-type thermo-couples and controlled by a program controller. The total thickness of the generator is designed to be as thin as possible, 20 cm in maximum, in the standing point of the neutron beam intensity. The thermal stability, controllability and safety of the generator at high temperature employment were confirmed by the heating tests. As one of the experiments for the characteristics estimation, the neutron energy spectrum dependent on the scatterer temperature was measured by the TOF (time of flight) method using the LINAC neutron generator. The estimations by simulation calculations were also performed. From the experiment and calculation results, it was confirmed that the neutron temperature shifted higher as the scatterer temperature was higher. The prospect of the feasibility of the 'hyper-thermal neutron irradiation field for NCT' was opened from the estimation results of the generator characteristics by the simulation calculations and experiments

  6. Compact neutron generator

    Science.gov (United States)

    Leung, Ka-Ngo; Lou, Tak Pui

    2005-03-22

    A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications. A luggage or cargo inspection system has a pulsed T-T neutron generator or source at the center, surrounded by associated gamma detectors and other components for identifying explosives or other contraband.

  7. A hospital-based proton linac for neutron therapy and radioisotope production

    International Nuclear Information System (INIS)

    Lennox, A.J.

    1988-10-01

    Fermilab's Alvarez proton linac has been used routinely for neutron therapy since 1976. The Neutron Therapy Facility (NTF) operates in a mode parasitic to the laboratory's high energy physics program, which uses the linac as an injector for a synchrotron. Parasitic operation is possible because the linac delivers /approximately/1.2 /times/ 10 13 protons per pulse at a 15 Hz rate, while the high energy physics program requires beam at a rate not greater than 0.5 Hz. Protons not needed for physics experiments strike a beryllium target to produce neutrons for neutron therapy. Encouraging clinical results from NTF have led to a study of the issues involved in providing hospitals with a neutron beam of the type available at Fermilab. This paper describes the issues addressed by that study. 12 refs., 1 fig., 1 tab

  8. A combined system for the generation of an intense cold neutron beam with a medium power research reactor

    International Nuclear Information System (INIS)

    Utsuro, M.; Okumura, K.

    1989-01-01

    A system consisting of a very cold moderator and a neutron-accelerating high speed turbine is proposed for the intensification of a cold neutron beam in a medium power research reactor up to the level applicable to inelastic neutron scattering spectrometers. A numerical result for 5 cm thick solid ortho-deuterium at a temperature of about 4 K and a turbine with a blade velocity of about 350 m/s gives an output intensity of monochromatic neutrons of about 10 7 n/cm 2 at an energy of about 3.5 meV with an energy width of about 0.2 meV for a typical case of a 5 MW reactor. (orig.)

  9. Design and simulation of an optimized e-linac based neutron source for BNCT research

    International Nuclear Information System (INIS)

    Durisi, E.; Alikaniotis, K.; Borla, O.; Bragato, F.; Costa, M.; Giannini, G.; Monti, V.; Visca, L.; Vivaldo, G.; Zanini, A.

    2015-01-01

    The paper is focused on the study of a novel photo-neutron source for BNCT preclinical research based on medical electron Linacs. Previous studies by the authors already demonstrated the possibility to obtain a mixed thermal and epithermal neutron flux of the order of 10"7 cm"−"2 s"−"1. This paper investigates possible Linac’s modifications and a new photo-converter design to rise the neutron flux above 5 10"7 cm"−"2 s"−"1, also reducing the gamma contamination. - Highlights: • Proposal of a mixed thermal and epithermal (named hyperthermal) neutron source based on medical high energy electron Linac. • Photo-neutron production via Giant Dipole Resonance on high Z materials. • MCNP4B-GN simulations to design the photo-converter geometry maximizing the hyperthermal neutron flux and minimizing the fast neutron and gamma contaminations. Hyperthermal neutron field suitable for BNCT preclinical research.

  10. 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

  11. Proton linac for hospital-based fast neutron therapy and radioisotope production

    International Nuclear Information System (INIS)

    Lennox, A.J.; Hendrickson, F.R.; Swenson, D.A.; Winje, R.A.; Young, D.E.

    1989-09-01

    Recent developments in linac technology have led to the design of a hospital-based proton linac for fast neutron therapy. The 180 microamp average current allows beam to be diverted for radioisotope production during treatments while maintaining an acceptable dose rate. During dedicated operation, dose rates greater than 280 neutron rads per minute are achievable at depth, DMAX = 1.6 cm with source to axis distance, SAD = 190 cm. Maximum machine energy is 70 MeV and several intermediate energies are available for optimizing production of isotopes for Positron Emission Tomography and other medical applications. The linac can be used to produce a horizontal or a gantry can be added to the downstream end of the linac for conventional patient positioning. The 70 MeV protons can also be used for proton therapy for ocular melanomas. 17 refs., 1 fig., 1 tab

  12. Generation and application of slow positrons based on a electron LINAC

    CERN Document Server

    Kurihara, T

    2002-01-01

    History of slow positron in Institute of Materials Structure Science High Energy Accelerator Research Organization is explained. The principle of generation and application of intense positron beam is mentioned. Two sources of intense positron are radioactive decay of radioactive isotopes emitting positron and electron-positron pair creation. The radioactive decay method uses sup 5 sup 8 Co, sup 6 sup 4 Cu, sup 1 sup 1 C, sup 1 sup 3 N, sup 1 sup 5 O and sup 1 sup 8 F. The electron-positron pair creation method uses nuclear reactor or electron linear accelerator (LINAC). The positron experimental facility in this organization consists of electron LINAC, slow positron beam source, positron transport and experimental station. The outline of this facility is started. The intense slow positron beam is applied to research positronium work function, electron structure of surface. New method such as combination of positron lifetime measurement and slow positron beam or Auger electron spectroscopy by positron annihil...

  13. Generation and application of slow positrons based on a electron LINAC

    International Nuclear Information System (INIS)

    Kurihara, Toshikazu

    2002-01-01

    History of slow positron in Institute of Materials Structure Science High Energy Accelerator Research Organization is explained. The principle of generation and application of intense positron beam is mentioned. Two sources of intense positron are radioactive decay of radioactive isotopes emitting positron and electron-positron pair creation. The radioactive decay method uses 58 Co, 64 Cu, 11 C, 13 N, 15 O and 18 F. The electron-positron pair creation method uses nuclear reactor or electron linear accelerator (LINAC). The positron experimental facility in this organization consists of electron LINAC, slow positron beam source, positron transport and experimental station. The outline of this facility is started. The intense slow positron beam is applied to research positronium work function, electron structure of surface. New method such as combination of positron lifetime measurement and slow positron beam or Auger electron spectroscopy by positron annihilation excitation and positron reemission microscope are developed. (S.Y.)

  14. Calculated intensity of high-energy neutron beams

    International Nuclear Information System (INIS)

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

    2004-01-01

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

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

    CERN Document Server

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

    2005-01-01

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

  16. High energy neutron generator

    International Nuclear Information System (INIS)

    Barjon, R.; Breynat, G.

    1987-01-01

    This patent describes a generator of fast neutrons only slightly contaminated by neutrons of energy less than 15 MeV, comprising a source of charged particles of energy equal to at least 15 MeV, a target made of lithium deuteride, and means for cooling the target. The target comprises at least two elements placed in series in the path of the charged particles and separated from each other, the thickness of each of the elements being selected as a function of the average energy of the charged particles emitted from the source and the energy of the fast neutrons to be generated such that neutrons of energy equal to at least 15 MeV are emitted in the forward direction in response to the bombardment of the target from behind by the charged particles. The target cooling means comprises means for circulating between and around the elements a gas which does not chemically react with lithium deuteride

  17. Radiotechnical Institute activity in the linac field

    International Nuclear Information System (INIS)

    Murin, B.P.

    1976-01-01

    For many years, the Radiotechnical Institute has been involved in a number of projects aimed at constructing linear accelerators for protons or electrons. This report summarizes the experience gained and covers 1) some problems of developing linacs to serve as meson or neutron generators, 2) results of study of a linac with asymmetric alternating phase focusing, and 3) electron linac projects. (author)

  18. High duty factor plasma generator for CERN's Superconducting Proton Linac.

    Science.gov (United States)

    Lettry, J; Kronberger, M; Scrivens, R; Chaudet, E; Faircloth, D; Favre, G; Geisser, J-M; Küchler, D; Mathot, S; Midttun, O; Paoluzzi, M; Schmitzer, C; Steyaert, D

    2010-02-01

    CERN's Linac4 is a 160 MeV linear accelerator currently under construction. It will inject negatively charged hydrogen ions into CERN's PS-Booster. Its ion source is a noncesiated rf driven H(-) volume source directly inspired from the one of DESY and is aimed to deliver pulses of 80 mA of H(-) during 0.4 ms at a 2 Hz repetition rate. The Superconducting Proton Linac (SPL) project is part of the luminosity upgrade of the Large Hadron Collider. It consists of an extension of Linac4 up to 5 GeV and is foreseen to deliver protons to a future 50 GeV synchrotron (PS2). For the SPL high power option (HP-SPL), the ion source would deliver pulses of 80 mA of H(-) during 1.2 ms and operate at a 50 Hz repetition rate. This significant upgrade motivates the design of the new water cooled plasma generator presented in this paper. Its engineering is based on the results of a finite element thermal study of the Linac4 H(-) plasma generator that identified critical components and thermal barriers. A cooling system is proposed which achieves the required heat dissipation and maintains the original functionality. Materials with higher thermal conductivity are selected and, wherever possible, thermal barriers resulting from low pressure contacts are removed by brazing metals on insulators. The AlN plasma chamber cooling circuit is inspired from the approach chosen for the cesiated high duty factor rf H(-) source operating at SNS.

  19. Spherical neutron generator

    Science.gov (United States)

    Leung, Ka-Ngo

    2006-11-21

    A spherical neutron generator is formed with a small spherical target and a spherical shell RF-driven plasma ion source surrounding the target. A deuterium (or deuterium and tritium) ion plasma is produced by RF excitation in the plasma ion source using an RF antenna. The plasma generation region is a spherical shell between an outer chamber and an inner extraction electrode. A spherical neutron generating target is at the center of the chamber and is biased negatively with respect to the extraction electrode which contains many holes. Ions passing through the holes in the extraction electrode are focused onto the target which produces neutrons by D-D or D-T reactions.

  20. Responses of conventional and extended-range neutron detectors in mixed radiation fields around a 150-MeV electron LINAC

    International Nuclear Information System (INIS)

    Lin, Yu-Chi; Sheu, Rong-Jiun; Chen, Ang-Yu

    2015-01-01

    This study analyzed the responses of two types of neutron detector in mixed gamma-ray and neutron radiation fields around a 150-MeV electron linear accelerator (LINAC). The detectors were self-assembled, high efficiency, and designed in two configurations: (1) a conventional moderated-type neutron detector based on a large cylindrical He-3 proportional counter; and (2) an extended-range version with an embedded layer of lead in the moderator to increase the detector’s sensitivity to high-energy neutrons. Two sets of the detectors were used to measure neutrons at the downstream and lateral locations simultaneously, where the radiation fields differed considerably in intensities and spectra of gamma rays and neutrons. Analyzing the detector responses through a comparison between calculations and measurements indicated that not only neutrons but also high-energy gamma rays (>5 MeV) triggered the detectors because of photoneutrons produced in the detector materials. In the lateral direction, the contribution of photoneutrons to both detectors was negligible. Downstream of the LINAC, where high-energy photons were abundant, photoneutrons contributed approximately 6% of the response of the conventional neutron detector; however, almost 50% of the registered counts of the extended-range neutron detector were from photoneutrons because of the presence of the detector rather than the effect of the neutron field. Dose readings delivered by extended-range neutron detectors should be interpreted cautiously when used in radiation fields containing a mixture of neutrons and high-energy gamma rays

  1. A time-of-flight detector for thermal neutrons from radiotherapy Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Conti, V. [Universita degli Studi di Milano and INFN di Milano (Italy)], E-mail: conti.Valentina@gmail.com; Bartesaghi, G. [Universita degli Studi di Milano and INFN di Milano (Italy); Bolognini, D.; Mascagna, V.; Perboni, C.; Prest, M.; Scazzi, S. [Universita dell' Insubria, Como and INFN di Milano (Italy); Mozzanica, A. [Universita degli Studi di Brescia and INFN sezione di Pavia (Italy); Cappelletti, P.; Frigerio, M.; Gelosa, S.; Monti, A.; Ostinelli, A. [Fisica Sanitaria, Ospedale S. Anna di Como (Italy); Giannini, G.; Vallazza, E. [INFN, sezione di Trieste and Universita degli Studi di Trieste (Italy)

    2007-10-21

    Boron Neutron Capture Therapy (BNCT) is a therapeutic technique exploiting the release of dose inside the tumour cell after a fission of a {sup 10}B nucleus following the capture of a thermal neutron. BNCT could be the treatment for extended tumors (liver, stomach, lung), radio-resistant ones (melanoma) or tumours surrounded by vital organs (brain). The application of BNCT requires a high thermal neutron flux (>5x10{sup 8}ncm{sup -2}s{sup -1}) with the correct energy spectrum (neutron energy <10keV), two requirements that for the moment are fulfilled only by nuclear reactors. The INFN PhoNeS (Photo Neutron Source) project is trying to produce such a neutron beam with standard radiotherapy Linacs, maximizing with a dedicated photo-neutron converter the neutrons produced by Giant Dipole Resonance by a high energy (>8MeV) photon beam. In this framework, we have developed a real-time detector to measure the thermal neutron time-of -flight to compute the flux and the energy spectrum. Given the pulsed nature of Linac beams, the detector is a single neutron counting system made of a scintillator detecting the photon emitted after the neutron capture by the hydrogen nuclei. The scintillator signal is sampled by a dedicated FPGA clock thus obtaining the exact arrival time of the neutron itself. The paper will present the detector and its electronics, the feasibility measurements with a Varian Clinac 1800/2100CD and comparison with a Monte Carlo simulation.

  2. Neutron generation in lightning bolts

    International Nuclear Information System (INIS)

    Shah, G.N.; Razdan, H.; Bhat, C.L.; Ali, Q.M.

    1985-01-01

    To ascertain neutron generation in lightning bolts, the authors have searched for neutrons from individual lightning strokes, for a time-interval comparable with the duration of the lightning stroke. 10 7 -10 10 neutrons per stroke were found, thus providing the first experimental evidence that neutrons are generated in lightning discharges. (U.K.)

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

    International Nuclear Information System (INIS)

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

    2001-01-01

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

  4. Progress in design of the SNS linac

    International Nuclear Information System (INIS)

    Hardekopf, R.

    2001-01-01

    The Spallation Neutron Source (SNS) is a six-laboratory collaboration to build an intense pulsed neutron facility at Oak Ridge, TN. The linac design has evolved from the conceptual design presented in 1997 in order to achieve higher initial performance and to incorporate desirable upgrade features. The linac is now designed to produce 2-MW beam power using a combination of radio-frequency quadrupole (RFQ) linac, drift-tube linac (DTL), coupled-cavity linac (CCL), and superconducting-RF (SRF) linac. Designs of each of these elements support he high peak intensity and high quality beam required for injection into the SNS accumulator ring. This paper will trace the evolution of the linac design and the progress made in the R and D program. (author)

  5. Preliminary design of the cold neutron source for the Centro Atomico Bariloche Electron LINAC Facility. I. Solid benzene as moderating material

    International Nuclear Information System (INIS)

    Torres, Lourdes; Granada, Jose R.

    2004-01-01

    We present the results of preliminary calculations performed with the code MCNP-4C relative to the neutron field behavior within the moderator for the CAB-LINAC cold neutron source, using benzene at 89 K as moderating material. Throughout the design calculations nuclear data libraries previously generated and validated were used. The optimum dimensions for a slab and a grid moderator were calculated, with and without a pre moderator, from the point of view of neutron production and the time-width of the neutron pulse. (author)

  6. Design of a high-current low-energy beam transport line for an intense D-T/D-D neutron generator

    International Nuclear Information System (INIS)

    Lu, Xiaolong; Wang, Junrun; Zhang, Yu; Li, Jianyi; Xia, Li; Zhang, Jie; Ding, Yanyan; Jiang, Bing; Huang, Zhiwu; Ma, Zhanwen; Wei, Zheng; Qian, Xiangping; Xu, Dapeng; Lan, Changlin; Yao, Zeen

    2016-01-01

    An intense D-T/D-D neutron generator is currently being developed at the Lanzhou University. The Cockcroft–Walton accelerator, as a part of the neutron generator, will be used to accelerate and transport the high-current low-energy beam from the duoplasmatron ion source to the rotating target. The design of a high-current low-energy beam transport (LEBT) line and the dynamics simulations of the mixed beam were carried out using the TRACK code. The results illustrate that the designed beam line facilitates smooth transportation of a deuteron beam of 40 mA, and the number of undesired ions can be reduced effectively using two apertures.

  7. Short pulse neutron generator

    Science.gov (United States)

    Elizondo-Decanini, Juan M.

    2016-08-02

    Short pulse neutron generators are described herein. In a general embodiment, the short pulse neutron generator includes a Blumlein structure. The Blumlein structure includes a first conductive plate, a second conductive plate, a third conductive plate, at least one of an inductor or a resistor, a switch, and a dielectric material. The first conductive plate is positioned relative to the second conductive plate such that a gap separates these plates. A vacuum chamber is positioned in the gap, and an ion source is positioned to emit ions in the vacuum chamber. The third conductive plate is electrically grounded, and the switch is operable to electrically connect and disconnect the second conductive plate and the third conductive plate. The at least one of the resistor or the inductor is coupled to the first conductive plate and the second conductive plate.

  8. Neutron beam design for low intensity neutron and gamma-ray radioscopy using small neutron sources

    CERN Document Server

    Matsumoto, T

    2003-01-01

    Two small neutron sources of sup 2 sup 5 sup 2 Cf and sup 2 sup 4 sup 1 Am-Be radioisotopes were used for design of neutron beams applicable to low intensity neutron and gamma ray radioscopy (LINGR). In the design, Monte Carlo code (MCNP) was employed to generate neutron and gamma ray beams suited to LINGR. With a view to variable neutron spectrum and neutron intensity, various arrangements were first examined, and neutron-filter, gamma-ray shield and beam collimator were verified. Monte Carlo calculations indicated that with a suitable filter-shield-collimator arrangement, thermal neutron beam of 3,900 ncm sup - sup 2 s sup - sup 1 with neutron/gamma ratio of 7x10 sup 7 , and 25 ncm sup - sup 2 s sup - sup 1 with very large neutron/gamma ratio, respectively, could be produced by using sup 2 sup 5 sup 2 Cf(122 mu g) and a sup 2 sup 4 sup 1 Am-Be(37GBq)radioisotopes at the irradiation port of 35 cm from the neutron sources.

  9. A real time scintillating fiber Time of Flight spectrometer for LINAC photoproduced neutrons

    Science.gov (United States)

    Maspero, M.; Berra, A.; Conti, V.; Giannini, G.; Ostinelli, A.; Prest, M.; Vallazza, E.

    2015-03-01

    The use of high-energy (> 8 MeV) LINear ACcelerators (LINACs) for medical cancer treatments causes the photoproduction of secondary neutrons, whose unwanted dose to the patient has to be calculated. The characterization of the neutron spectra is necessary to allow the dosimetric evaluation of the neutron beam contamination. The neutron spectrum in a hospital environment is usually measured with integrating detectors such as bubble dosimeters, Thermo Luminescent Dosimeters (TLDs) or Bonner Spheres, which integrate the information over a time interval and an energy one. This paper presents the development of a neutron spectrometer based on the Time of Flight (ToF) technique in order to perform a real time characterization of the neutron contamination. The detector measures the neutron spectrum exploiting the fact that the LINAC beams are pulsed and arranged in bunches with a rate of 100-300 Hz depending on the beam type and energy. The detector consists of boron loaded scintillating fibers readout by a MultiAnode PhotoMultiplier Tube (MAPMT). A detailed description of the detector and the acquisition system together with the results in terms of ToF spectra and number of neutrons with a Varian Clinac iX are presented.

  10. Jet target intense neutron source

    International Nuclear Information System (INIS)

    Meier, K.L.

    1977-01-01

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

  11. Optimization calculations for slow neutron production with the 136 MeV Harwell electron linac

    International Nuclear Information System (INIS)

    Needham, J.; Sinclair, R.N.

    1978-10-01

    The new 136 MeV Harwell electron linac is to be used to produce pulsed beams of slow neutrons for condensed matter research. Design details and performance of the two types of moderator which will be available have been optimised using a Monte Carlo neutronics code (TIMOC). The choice of reflector, the necessary decoupling energy to prevent pulse broadening and the influence of γ shields and moderator shape have been investigated. The predicted yield of leakage neutrons of energy 1 eV is compared to published values for comparable facilities. (author)

  12. Spectrum and H(10) of secondary neutrons around Linacs

    International Nuclear Information System (INIS)

    Ortiz H, A.; Hernandez A, B.; Vega C, H. R.; Hernandez D, V. M.; Rivera M, T.

    2009-10-01

    Neutron spectrum and ambient dose equivalent has been measured around two 10 MV linear accelerators. Accelerators are Siemens, one is a Mevatron model while another is the Primus. Main differences between those models are the beam collimator and the vault room. Here, Bonner sphere spectrometer with a passive thermal neutron detector has been utilized to measure the neutron spectrum inside the vault. Using an active detector the neutron spectrum was measured by the vaults door of both accelerators. With a neutron area monitor the dose equivalent was measured by the doors. Neutron strength, total fluence rate and ambient dose equivalent were compared, from this was found that shielding conditions are better in the Primus model. (Author)

  13. Fast Neutron Dose Distribution in a Linac Radiotherapy Facility

    International Nuclear Information System (INIS)

    Al-Othmany, D.Sh.; Abdul-Majid, S.; Kadi, M.W.

    2011-01-01

    CR-39 plastic detectors were used for fast neutron dose mapping in the radiotherapy facility at King AbdulAziz University Hospital (KAUH). Detectors were calibrated using a 252 Cf neutron source and a neutron dosimeter. After exposure chemical etching was performed using 6N NaOH solution at 70 degree C. Tracks were counted using an optical microscope and the number of tracks/cm 2 was converted to a neutron dose. 15 track detectors were distributed inside and outside the therapy room and were left for 32 days. The average neutron doses were 142.3 mSv on the accelerator head, 28.5 mSv on inside walls, 1.4 mSv beyond the beam shield, and 1 mSv in the control room

  14. Measurement of thermal neutron spectra using LINAC in Japan Atomic Energy Research Institute (JAERI)

    International Nuclear Information System (INIS)

    Akino, Fujiyoshi

    1982-01-01

    The exact grasp of thermal neutron spectra in a core region is very important for obtaining accurate thermal neutron group constants in the calculation for the nuclear design of a reactor core. For the accurate grasp of thermal neutron spectra, the capability of thermal neutron spectra to describe the moderator cross-sections for thermal neutron scattering is a key factor. Accordingly, 0 deg angular thermal neutron spectra were measured by the time of flight (TOF) method using the JAERI LINAC as a pulsed neutron source, for light water system added with Cd and In, high temperature graphite system added with boron, and light water-natural uranium heterogeneous multiplication system among the reactor moderators of light water or graphite systems. First, the equations to give the time of flight and neutron flux by TOF method were analyzed, and several corrections were investigated, such as those for detector efficiency, background, the transmission coefficient of air and the Al window of a flight tube, mean emission time of neutrons, and the distortion effect of re-entrant hole on thermal neutron spectra. Then, the experimental system, results and calculation were reported for the experiments on the above three moderator systems. Finally, the measurement of fast neutron spectra in natural uranium system and that of the efficiency of a 6 Li glass scintillator detector are described. (Wakatsuki, Y.)

  15. Design of neutron beams at the Argonne Continuous Wave Linac (ACWL) for boron neutron capture therapy and neutron radiography

    International Nuclear Information System (INIS)

    Zhou, X.L.; McMichael, G.E.

    1994-01-01

    Neutron beams are designed for capture therapy based on p-Li and p-Sc reactions using the Argonne Continuous Wave Linac (ACWL). The p-Li beam will provide a 2.5 x 10 9 n/cm 2 s epithermal flux with 7 x 10 5 γ/cm 2 s contamination. On a human brain phantom, this beam allows an advantage depth (AD) of 10 cm, an advantage depth dose rate (ADDR) of 78 cGy/min and an advantage ratio (AR) of 3.2. The p-Sc beam offers 5.9 x 10 7 n/cm 2 s and a dose performance of AD = 8 cm and AR = 3.5, suggesting the potential of near-threshold (p,n) reactions such as the p-Li reaction at E p = 1.92 MeV. A thermal radiography beam could also be obtained from ACWL

  16. Status and performance of PF injector linac

    International Nuclear Information System (INIS)

    Sato, Isamu

    1994-01-01

    PF injector linac has been improved on a buncher section for accelerating of intense electron beam, and reinforced a focusing system of the positron generator linac for the expansion of phase space. In this presentation, I shall report present status and performance of PF injector linac, and discuss its upgrade program for B-factory project. (author)

  17. Integrating techniques for neutron dosimetry in Linac 18 MV

    International Nuclear Information System (INIS)

    Ceron R, P. V.; Diaz G, J. A. I.; Rivera M, T.; Paredes G, L. C.; Vega C, H. R.

    2015-10-01

    In this paper thermoluminescent dosimetry, analytical techniques and Monte Carlo calculations were used to estimate the neutron dose equivalent in a radiotherapy room with a linear electron accelerator of 18 MV. The equivalent dose was measured at isocenter to 1.42 m of target and at the entrance of the labyrinth of the room of a Novalis Tx. The neutron detectors were constructed with pairs of thermoluminescent dosimeters TLD 600 ( 6 LiF: Mg, Ti) and TLD 700 ( 7 LiF: Mg, Ti) which are placed inside a paraffin sphere of 20 cm in diameter. These measurements enabled the calculation of equivalent dose in the gate and the source term, using the relationships contained in the NCRP-151. Through the models carried out with the code MCNPX the absorbed dose distribution with regard to depth in a paraffin phantom are included and the neutron spectrum produced by the head, taking into account the geometry and component materials. The results are in the order of neutron milli sievert by gray of X-rays (mSv/Gy x) which are in the same order as those found in other reports for different accelerators. (Author)

  18. Conformal intensity-modulated radiotherapy (IMRT) delivered by robotic linac - testing IMRT to the limit?

    International Nuclear Information System (INIS)

    Webb, S.

    1999-01-01

    In this paper it is proposed that intensity-modulated radiotherapy (IMRT) could be delivered optimally by a short-length linac mounted on a robotic arm. The robot would allow the linac to 'plant' narrow pencils of photon radiation with any orientation (excluding zones within which the linac and couch might collide) relative to the planning target volume (PTV). The treatment is specified by the trajectory of the robot and by the number of monitor units (MUs) delivered at each robotic orientation. An inverse-planning method to determine the optimum robotic trajectory is presented. It is shown that for complex PTVs, specifically those with concavities in their outline, the conformality of the treatment is improved by the use of a complex trajectory in comparison with a less complex constrained trajectory and this improvement is quantified. It is concluded that robotic linac delivery would lead to a great flexibility in those IMRT treatments requiring very complicated dose distributions with complex 3D shapes. However, even using very fast computers, the goal of determining whether robotic linac delivery is the ultimate IMRT cannot be conclusively reached at present. (author)

  19. Generation of an intense pulsed positron beam and its applications

    International Nuclear Information System (INIS)

    Suzuki, Ryoichi; Mikado, Tomohisa; Ohgaki, Hideaki; Chiwaki, Mitsukuni; Yamazaki, Tetsuo; Kobayashi, Yoshinori.

    1994-01-01

    A positron pulsing system for an intense positron beam generated by an electron linac has been developed at the Electrotechnical Laboratory. The pulsing system generates an intense pulsed positron beam of variable energy and variable pulse period. The pulsed positron beam is used as a non destructive probe for various materials researches. In this paper, we report the present status of the pulsed positron beam and its applications. (author)

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

    International Nuclear Information System (INIS)

    Swain, G.R.

    1993-01-01

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

  1. SU-F-BRE-11: Neutron Measurements Around the Varian TrueBeam Linac

    Energy Technology Data Exchange (ETDEWEB)

    Maglieri, R; Seuntjens, J; Kildea, J [McGill University, Montreal, QC (Canada); Liang, L; DeBlois, F [Jewish General Hospital, Montreal, QC (Canada); Evans, M [Montreal General Hospital, Montreal, QC (Canada); Licea, A [Canadian Nuclear Safety Comission, Ottawa, Ontario (Canada); Dubeau, J; Witharana, S [Detec, Gatineau, QC (Canada)

    2014-06-15

    Purpose: With the emergence of flattening filter free (FFF) photon beams, several authors have noted many advantages to their use. One such advantage is the decrease in neutron production by photonuclear reactions in the linac head. In the present work we investigate the reduction in neutrons from a Varian TrueBeam linac using the Nested Neutron Spectrometer (NNS, Detec). The neutron spectrum, total fluence and source strength were measured and compared for 10 MV with and without flattening filter and the effect of moderation by the room and maze was studied for the 15 MV beam. Methods: The NNS, similar to traditional Bonner sphere detectors but operated in current mode, was used to measure the neutron fluence and spectrum. The NNS was validated for use in high dose rate environments using Monte Carlo simulations and calibrated at NIST and NRC Canada. Measurements were performed at several positions within the treatment room and maze with the linac jaws closed to maximize neutron production. Results: The measurements showed a total fluence reduction between 35-40% in the room and maze when the flattening filter was removed. The neutron source strength Qn was calculated from in-room fluence measurements and was found to be 0.042 × 10{sup 2} n/Gy, 0.026 × 10{sup 2} n/Gy and 0.59 × 101{sup 2} n/Gy for the 10 MV, the 10 MV FFF and 15 MV beams, respectively. We measured ambient equivalent doses of 11 mSv/hr, 7 mSv/hr and 218 mSv/hr for the 10 MV, 10 MV FFF and 15 MV by the head. Conclusion: Our measurements revealed a decrease in total fluence, neutron source strength and equivalent dose of approximately 35-40% across the treatment room for the FFF compared to FF modes. This demonstrates, as expected, that the flattening filter is a major component of the neutron production for the TrueBeam. The authors greatly acknowledge support form the Canadian Nuclear Commission and the Natural Sciences and Engineering Research Council of Canada through the CREATE program. Co

  2. Pulsed neutron generator for logging

    International Nuclear Information System (INIS)

    Thibideau, F.D.

    1977-01-01

    A pulsed neutron generator for uranium logging is described. This generator is one component of a prototype uranium logging probe which is being developed by SLA to detect, and assay, uranium by borehole logging. The logging method is based on the measurement of epithermal neutrons resulting from the prompt fissioning of uranium from a pulsed source of 17.6 MeV neutrons. An objective of the prototype probe was that its diameter not exceed 2.75 inches, which would allow its use in conventional rotary drill holes of 4.75-inch diameter. This restriction limited the generator to a maximum 2.375-inch diameter. The performance requirements for the neutron generator specified that it operate with a nominal output of 5 x 10 6 neutrons/pulse at up to 100 pulses/second for a one-hour period. The development of a neutron generator meeting the preliminary design goals was completed and two prototype models were delivered to SLA. These two generators have been used by SLA to log a number of boreholes in field evaluation of the probe. The results of the field evaluations have led to the recommendation of several changes to improve the probe's operation. Some of these changes will require additional development effort on the neutron generator. It is expected that this work will be performed during 1977. The design and operation of the first prototype neutron generators is described

  3. A compact mobile neutron generator

    International Nuclear Information System (INIS)

    Zhou Changgeng; Li Yan; Hu Yonghong; Lou Benchao; Wu Chunlei

    2007-06-01

    Through fitting the high voltage terminal from introducing overseas and pulse system et al. from oneself developing together, a compact mobile neutron generator is established. The length and weight of this neutron generator are 2 500 mm and less than 1 t, respectively. It can be expediently moved to the location which is required by experimental people. It is consisted of RF ion source, acceleration tube, high voltage generator, focus device, microsecond pulse system, gas leak system, control system, vacuum system and experimental target. It can produce 150 μA continuous deuterium ion beam current, also can produce the pulse deuterium ion beam current. The pulse widths are 10-100 μs and frequencies 10 Hz, 1 000 Hz, 10 000 Hz. The D-T neutron yields of the neutron generator may arrive 1.5 x 10 10 s -1 . The working principle and the structure of the main parts of this neutron generator are described. (authors)

  4. Design of a 120 MeV $H^{-}$ Linac for CERN High-Intensity Applications

    CERN Document Server

    Gerigk, F

    2002-01-01

    The SPL (Superconducting Proton Linac) study at CERN foresees the construction of a 2.2 GeV linac as a high beam-power driver for applications such as a second-generation radioactive ion beam facility or a neutrino superbeam. At the same time such a high-performance injector would both modernize and improve the LHC injection chain. The 120 MeV normal-conducting section of the SPL could be used directly in a preliminary stage for H- charge-exchange injection into the PS Booster. This would increase the proton flux to the CERN experiments while also improving the quality and reliability of the beams for the LHC. The 120 MeV linac consists of a front-end, a conventional Drift Tube Linac (DTL) to 40 MeV and a Cell Coupled Drift Tube Linac (CCDTL) to the full energy. All the RF structures will operate at 352 MHz, using klystrons and RF equipment recovered from the LEP collider. This paper concentrates on the design of the 3 to 120 MeV section. It introduces the design criteria for high-stability beam optics and th...

  5. Stabilization of the Beam Intensity in the Linac at the CTF3 CLIC Test Facility

    CERN Document Server

    Dubrovskiy, A; Bathe, BN; Srivastava, S

    2013-01-01

    A new electron beam stabilization system has been introduced in CTF3 in order to open new possibilities for CLIC beam studies in ultra-stable conditions and to provide a sustainable tool to keep the beam intensity and energy at its reference values for long term operations. The stabilization system is based on a pulse-to-pulse feedback control of the electron gun to compensate intensity deviations measured at the end of the injector and at the beginning of the linac. Thereby it introduces negligible beam distortions at the end of the linac and it significantly reduces energy deviations. A self-calibration mechanism has been developed to automatically configure the feedback controller for the optimum performance. The residual intensity jitter of 0.045% of the stabilized beam was measured whereas the CLIC requirement is 0.075%.

  6. Beam dynamics studies of a 30 MeV RF linac for neutron production

    Science.gov (United States)

    Nayak, B.; Krishnagopal, S.; Acharya, S.

    2018-02-01

    Design of a 30 MeV, 10 Amp RF linac as neutron source has been carried out by means of ASTRA simulation code. Here we discuss details of design simulations for three different cases i.e Thermionic , DC and RF photocathode guns and compare them as injectors to a 30 MeV RF linac for n-ToF production. A detailed study on choice of input parameters of the beam from point of view of transmission efficiency and beam quality at the output have been described. We found that thermionic gun isn't suitable for this application. Both DC and RF photocathode gun can be used. RF photocathode gun would be of better performance.

  7. Neutron generators at Purnima Lab

    International Nuclear Information System (INIS)

    Patel, Tarun; Sinha, Amar

    2015-01-01

    Neutron sources are in a great demand in many area like research, nuclear waste management, industrial process control, medical and also security. Major sources of neutrons are nuclear reactors, radioisotopes and accelerator based neutron generators. For many field applications, reactors cannot be used due to its large size, complicated system, high cost and also safety issues. Radioisotopes like Pu-Be, Am-Be, Cf, are extensively used for many industrial applications. But they are limited in their use due to their low source strength and also handling difficulties due to radioactivity. They are also not suitable for pulsed neutron applications. In contrast, compact size, pulsed operation, on/off operation etc.of accelerator based neutron generators make them very popular for many applications. Particle accelerators based on different types of neutron generators have been developed around the world. Among these deuteron accelerator based D-D and D-T neutron generators are widely used as they produce mono-energetic fast neutrons and in particular high yield of D-T neutron can be obtained with less than 300 KV of accelerating voltage

  8. Proton energy dependence of slow neutron intensity

    International Nuclear Information System (INIS)

    Teshigawara, Makoto; Harada, Masahide; Watanabe, Noboru; Kai, Tetsuya; Sakata, Hideaki; Ikeda, Yujiro

    2001-01-01

    The choice of the proton energy is an important issue for the design of an intense-pulsed-spallation source. The optimal proton beam energy is rather unique from a viewpoint of the leakage neutron intensity but no yet clear from the slow-neutron intensity view point. It also depends on an accelerator type. Since it is also important to know the proton energy dependence of slow-neutrons from the moderators in a realistic target-moderator-reflector assembly (TMRA). We studied on the TMRA proposed for Japan Spallation Neutron Source. The slow-neutron intensities from the moderators per unit proton beam power (MW) exhibit the maximum at about 1-2 GeV. At higher proton energies the intensity per MW goes down; at 3 and 50 GeV about 0.91 and 0.47 times as low as that at 1 GeV. The proton energy dependence of slow-neutron intensities was found to be almost the same as that of total neutron yield (leakage neutrons) from the same bare target. It was also found that proton energy dependence was almost the same for the coupled and decoupled moderators, regardless the different moderator type, geometry and coupling scheme. (author)

  9. Neutron spectra and H*(10) around and 18 MV Linac by Ann's

    Energy Technology Data Exchange (ETDEWEB)

    Banuelos F, A.; Valero L, C.; Borja H, C. G.; Hernandez D, V. M.; Vega C, H. R., E-mail: alanb535@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2011-10-15

    Neutron spectra and ambient dose equivalent H*(10) were calculated for a radiotherapy room in 16 point-like detectors, 15 located inside the vault room and 1 located outside the bunker. The calculation was carried out using Monte Carlo Methods with the MCNP5 code for a generic radiotherapy room model operating with a 18 MV Linac, obtaining 16 neutron spectra with 47 energy bins, the H*(10) values were calculated from the neutron spectra by the use of the fluence-dose conversion factors. An artificial neural network were designed and trained to determine the neutron H*(10) in 15 different locations inside the vault room from the H*(10) dose calculated for the detector located outside the room, using the calculated dose values as training set, using the scaled conjugated gradient training algorithm. The mean squared error set for the network training was 1E(-14), adjusting the data in 99.992 %. In the treatment hall, as the distance respect to the isocenter is increased, the amount of neutrons and the H*(10) are reduced, neutrons in the high-energy region are shifted to lower region peaking around 0.1 MeV, however the epithermal and thermal neutrons remain constant due to the room-return effect. In the maze the spectra are dominated by epithermal and thermal neutrons that contributes to produce activation and the production of prompt gamma-rays. The results shows the using this artificial intelligence technic as a useful tool for the neutron spectrometry and dosimetry by the simplification on the neutronic fields characterization inside radiotherapy rooms avoiding the use of traditional spectrometric systems. And once the H*(10) doses have been calculated, to take the appropriated actions to reduce or prevent the patient and working staff exposure to this undesirable neutron radiation. (Author)

  10. Neutron spectra and H*(10) around and 18 MV Linac by Ann's

    International Nuclear Information System (INIS)

    Banuelos F, A.; Valero L, C.; Borja H, C. G.; Hernandez D, V. M.; Vega C, H. R.

    2011-10-01

    Neutron spectra and ambient dose equivalent H*(10) were calculated for a radiotherapy room in 16 point-like detectors, 15 located inside the vault room and 1 located outside the bunker. The calculation was carried out using Monte Carlo Methods with the MCNP5 code for a generic radiotherapy room model operating with a 18 MV Linac, obtaining 16 neutron spectra with 47 energy bins, the H*(10) values were calculated from the neutron spectra by the use of the fluence-dose conversion factors. An artificial neural network were designed and trained to determine the neutron H*(10) in 15 different locations inside the vault room from the H*(10) dose calculated for the detector located outside the room, using the calculated dose values as training set, using the scaled conjugated gradient training algorithm. The mean squared error set for the network training was 1E(-14), adjusting the data in 99.992 %. In the treatment hall, as the distance respect to the isocenter is increased, the amount of neutrons and the H*(10) are reduced, neutrons in the high-energy region are shifted to lower region peaking around 0.1 MeV, however the epithermal and thermal neutrons remain constant due to the room-return effect. In the maze the spectra are dominated by epithermal and thermal neutrons that contributes to produce activation and the production of prompt gamma-rays. The results shows the using this artificial intelligence technic as a useful tool for the neutron spectrometry and dosimetry by the simplification on the neutronic fields characterization inside radiotherapy rooms avoiding the use of traditional spectrometric systems. And once the H*(10) doses have been calculated, to take the appropriated actions to reduce or prevent the patient and working staff exposure to this undesirable neutron radiation. (Author)

  11. Intense neutron source facility for the fusion energy program

    International Nuclear Information System (INIS)

    Armstrong, D.D.; Emigh, C.R.; Meier, K.L.; Meyer, E.A.; Schneider, J.D.

    1975-01-01

    The Intense Neutron Source Facility, INS, has been proposed to provide a neutronic environment similar to that anticipated in a fully operational fusion-power reactor. The neutron generator will produce an intense flux of 14-MeV neutrons greater than 10 14 neutrons per cm 2 /sec from the collision of two intersecting beams, one of 1.1 A of 270 keV tritium ions and the other of a supersonic jet of deuterium gas. Using either the pure 14-MeV primary neutron spectrum or by tailoring the spectrum with appropriate moderators, crucial radiation-damage effects which are likely to occur in fusion reactors can be thoroughly explored and better understood

  12. Mutual compensation of wakefield and chromatic effects of intense linac bunches

    International Nuclear Information System (INIS)

    Seeman, J.T.; Merminga, N.

    1990-05-01

    Mutual compensation of transverse and chromatic effects for intense electron bunches in a high-energy linac is a recent Novosibirsk idea which provides a new control of emittance enlargement. In this paper we elaborate on the principles and constraints for this new technique which requires careful matching of internal bunch parameters with external forces. With species values of the bunch length, bunch intensity, and klystron phasing, the transverse-wakefield-induced forces within the bunch can be cancelled by energy-dependent forces from the quadrupole lattice at all positions along the linac. Under these conditions the tolerances for quadrupole alignment, dipole stability, and injection launch errors are significantly relaxed. 7 refs., 8 figs

  13. Neutron intensity of fast reactor spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Takamatsu, Misao; Aoyama, Takafumi [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1998-03-01

    Neutron intensity of spent fuel of the JOYO Mk-II core with a burnup of 62,500 MWd/t and cooling time of 5.2 years was measured at the spent fuel storage pond. The measured data were compared with the calculated values based on the JOYO core management code system `MAGI`, and the average C/E approximately 1.2 was obtained. It was found that the axial neutron intensity didn`t simply follow the burnup distribution, and the neutron intensity was locally increased at the bottom end of the fuel region due to an accumulation of {sup 244}Cm. (author)

  14. 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 ...

  15. Performance of the second Deep Inelastic Neutron Scatering spectrometer at the Bariloche electron LINAC

    International Nuclear Information System (INIS)

    Palomino, L A Rodríguez; Blostein, J J; Dawidowski, J

    2013-01-01

    We report on the new Deep Inelastic Neutron Scattering detector bank recently implemented at the Bariloche electron LINAC. We show the characterization and calibration process carried out, which comprises the determinarion of the detector bank efficiency, and the evaluation of the performance of the filter difference technique. As part of the benchmarking process, polyethylene spectra were measured and analyzed, and the scattering cross sections for carbon and hydrogen were determined in the process. With the addition of this new detector bank to the existing one, we evaluate the combined capacity of the two banks

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

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1989-01-01

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

  17. Beam loss studies in high-intensity heavy-ion linacs

    International Nuclear Information System (INIS)

    Ostroumov, P.N.; Aseev, V.N.; Lessner, E.S.; Mustapha, B.

    2004-01-01

    A low beam-loss budget is an essential requirement for high-intensity machines and represents one of their major design challenges. In a high-intensity heavy-ion machine, losses are required to be below 1 W/m for hands-on-maintenance. The driver linac of the Rare Isotope Accelerator (RIA) is designed to accelerate beams of any ion to energies from 400 MeV per nucleon for uranium up to 950 MeV for protons with a beam power of up to 400 kW. The high intensity of the heaviest ions is achieved by acceleration of multiple-charge-state beams, which requires a careful beam dynamics optimization to minimize effective emittance growth and beam halo formation. For beam loss simulation purposes, large number of particles must be tracked through the linac. Therefore the computer code TRACK has been parallelized and calculations are being performed on the JAZZ cluster recently inaugurated at ANL. This paper discusses how this powerful tool is being used for simulations for the RIA project to help decide on the high-performance and cost-effective design of the driver linac

  18. High intensity proton linear accelerator for Neutron Science Project

    International Nuclear Information System (INIS)

    Mizumoto, Motoharu

    1999-01-01

    JAERI has been proposing the Neutron Science Project (NSP) which will be composed of a high intensity proton accelerator and various research facilities. With an energy of 1.5 GeV and a beam power of 8 MW, the accelerator is required for basic research fields and nuclear waste transmutation studies. The R and D work has been carried out for the components of the accelerator. In the low energy accelerator part, a beam test with an ion source and an RFQ has been performed with a current of 80 mA and a duty factor of 10% at an energy of 2 MeV. A 1 m long high power test model of DTL has been fabricated and tested with a duty factor of 20%. In the high energy accelerator part, a superconducting (SC) linac has been selected as a main option from 100 MeV to 1.5 GeV. A test stand for SC linac cavity with equipment of cryogenics, vacuum, RF source and cavity processing and cleaning system has been prepared to test the fabrication process and physics issues. The vertical tests of β = 0.5 (145 MeV) and β = 0.89 (1.1 GeV) single cell SC cavities have been made resulting in a maximum electric field strength of 44 MV/m and 47 MV/m at 2 K, respectively. (author)

  19. Generation and application of 15 to 30 MeV parametric X-ray by linac

    CERN Document Server

    Akimoto, T

    2002-01-01

    15 to 30 MeV parametric X-ray (PXR) was generated using Si single crystal by 45 MeV electron LINAC. To obtain good monochromatic hard X-ray field, the appropriate conditions were determined by theoretical analysis and experiments. The intensity of PXR was increased with increasing electron energy and crystal rotation angle. However, PXR energy is independent of electron energy. By increasing measurement angle, energy of PXR decreased, but its intensity increased. 15 to 30 keV PXR energy and about 10 sup - sup 5 to 10 sup - sup 6 photon/electron of intensity were observed at 15 to 22 deg detection angle under the operation conditions of 45 MeV electron energy and 4 to 8 nA of beam current. The mass attenuation coefficient of photon of Zr, Nb and Mo, in K absorption edge was measured. Application to determine lattice distortion of target sample and off-angle of crystal was investigated. Generation and detection of PXR, measurement of characteristic properties: crystal rotation angle, detection angle, electron e...

  20. The Design of a Moderator for a Cold Neutron Source for the LINAC of the Centro Atomico Bariloche

    International Nuclear Information System (INIS)

    Torres, Lourdes; Gilette, Victor

    2003-01-01

    The results obtained in the design of a moderator to a cold neutron source for LINAC are given. Light water ice at 100 deg K was used as a moderator and we calculated its optimum dimension.We also calculated a grid moderator

  1. Neutron dose measurements of Varian and Elekta linacs by TLD600 and TLD700 dosimeters and comparison with MCNP calculations.

    Science.gov (United States)

    Nedaie, Hassan Ali; Darestani, Hoda; Banaee, Nooshin; Shagholi, Negin; Mohammadi, Kheirollah; Shahvar, Arjang; Bayat, Esmaeel

    2014-01-01

    High-energy linacs produce secondary particles such as neutrons (photoneutron production). The neutrons have the important role during treatment with high energy photons in terms of protection and dose escalation. In this work, neutron dose equivalents of 18 MV Varian and Elekta accelerators are measured by thermoluminescent dosimeter (TLD) 600 and TLD700 detectors and compared with the Monte Carlo calculations. For neutron and photon dose discrimination, first TLDs were calibrated separately by gamma and neutron doses. Gamma calibration was carried out in two procedures; by standard 60Co source and by 18 MV linac photon beam. For neutron calibration by (241)Am-Be source, irradiations were performed in several different time intervals. The Varian and Elekta linac heads and the phantom were simulated by the MCNPX code (v. 2.5). Neutron dose equivalent was calculated in the central axis, on the phantom surface and depths of 1, 2, 3.3, 4, 5, and 6 cm. The maximum photoneutron dose equivalents which calculated by the MCNPX code were 7.06 and 2.37 mSv.Gy(-1) for Varian and Elekta accelerators, respectively, in comparison with 50 and 44 mSv.Gy(-1) achieved by TLDs. All the results showed more photoneutron production in Varian accelerator compared to Elekta. According to the results, it seems that TLD600 and TLD700 pairs are not suitable dosimeters for neutron dosimetry inside the linac field due to high photon flux, while MCNPX code is an appropriate alternative for studying photoneutron production.

  2. Design of a cold neutron source for 25MeV Linac of CAB (Centro Atomico Bariloche - Argentina)

    International Nuclear Information System (INIS)

    Torres, Lourdes

    2006-01-01

    Cold neutrons are widely used in fields of research such as the dynamics of solids and liquids, the investigation of magnetic materials, material science, biology, and nuclear physics in general. Accelerator-based cold neutron sources have already proved to be well adapted to perform neutron scattering studies in all those fields.In this work we present the design of a cold neutron source in the electron Linac-based pulsed source at Centro Atomico Bariloche.The objective of this work is to develop an inexpensive yet efficient cold source with a simple moderator material.Although ideal materials for that purpose would be solid methane or liquid H2, due to economical and safety reasons light water ice, benzene or solid mesitylene were considered as cold moderators. In order to proceed with the design and optimization process of the neutron source, total cross sections for light water ice, benzene and mesitylene were measured at low temperature and thermal nuclear data libraries for such materials had to be developed.The purpose of these calculations was to optimize shape and size for the moderator at a working temperature.To calculations were performed using the MCNP-4C code and our libraries, together with files for (free-atom) carbon, hydrogen and oxygen at that temperature.The geometry studied consisted of a neutron source and different moderator (slab, cylindrical slab, grids, and sets premoderator - moderator with and without coupled).To simplify the system cooler, the slab geometry was changed to a coin shaped moderator using liquid nitrogen as cooler.From the variety of simulations performed, it was clear that a premoderator was necessary to obtain higher intensities.Furthermore, with a premoderator the thickness of the moderator was reduced, simplifying the cooling system.Finally, we adopted for our cold neutron source, a slab premoderator of PLE at room temperature, and a cylindrical moderator of mesitylene at 89K with a cooler system of stainless steel with

  3. Sci-Sat AM: Brachy - 04: Neutron production around a radiation therapy linac bunker - monte carlo simulations and physical measurements.

    Science.gov (United States)

    Khatchadourian, R; Davis, S; Evans, M; Licea, A; Seuntjens, J; Kildea, J

    2012-07-01

    Photoneutrons are a major component of the equivalent dose in the maze and near the door of linac bunkers. Physical measurements and Monte Carlo (MC) calculations of neutron dose are key for validating bunker design with respect to health regulations. We attempted to use bubble detectors and a 3 He neutron spectrometer to measure neutron equivalent dose and neutron spectra in the maze and near the door of one of our bunkers. We also ran MC simulations with MCNP5 to measure the neutron fluence in the same region. Using a point source of neutrons, a Clinac 1800 linac operating at 10 MV was simulated and the fluence measured at various locations of interest. We describe the challenges faced when measuring dose with bubble detectors in the maze and the complexity of photoneutron spectrometry with linacs operating in pulsed mode. Finally, we report on the development of a userfriendly GUI for shielding calculations based on the NCRP 151 formalism. © 2012 American Association of Physicists in Medicine.

  4. Effect of high current electron beam in a 30 MeV radio frequency linac for neutron-time-of-flight applications

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, B., E-mail: biswaranjan.nayak1@gmail.com; Acharya, S.; Rajawat, R. K. [Accelerator and Pulsed Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); DasGupta, K. [Accelerator and Pulsed Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Beam Technology Development Group, BARC, Mumbai 400085 (India)

    2016-01-15

    A high power pulsed radio frequency electron linac is designed by BARC, India to accelerate 30 MeV, 10 A, 10 ns beam for neutron-time-of-flight applications. It will be used as a neutron generator and will produce ∼10{sup 12}–10{sup 13} n/s. It is essential to reduce the beam instability caused by space charge effect and the beam cavity interaction. In this paper, the wakefield losses in the accelerating section due to bunch of RMS (Root mean square) length 2 mm (at the gun exit) is analysed. Loss and kick factors are numerically calculated using CST wakefield solver. Both the longitudinal and transverse wake potentials are incorporated in beam dynamics code ELEGANT to find the transverse emittance growth of the beam propagating through the linac. Beam loading effect is examined by means of numerical computation carried out in ASTRA code. Beam break up start current has been estimated at the end of the linac which arises due to deflecting modes excited by the high current beam. At the end, transverse beam dynamics of such high current beam has been analysed.

  5. Construction and use of an intense positron source at new linac facilities in Germany. Conceptual report

    International Nuclear Information System (INIS)

    Brauer, G.

    2000-07-01

    In this conceptual report the idea to establish an European positron source for applied research (''EPOS'') based on new LINAC facilities in Germany (ELBE/Rossendorf or TTF-DESY/Hamburg) is considered. The report contains not only the outline of obvious applications in atomic physics, materials science and surface physics, but also several new methodical developments which are only possible with an intense positron beam. This opportunity will also allow the use and further development of imaging techniques being of special interest for industrial applications. (orig.)

  6. Pulsed neutron generator for use with pulsed neutron activation techniques

    International Nuclear Information System (INIS)

    Rochau, G.E.

    1980-01-01

    A high-output, transportable, pulsed neutron generator has been developed by Sandia National Laboratories for use with Pulsed Neutron Activation (PNA) techniques. The PNA neutron generator generates > 10 10 14 MeV D-T neutrons in a 1.2 millisecond pulse. Each operation of the unit will produce a nominal total neutron output of 1.2 x 10 10 neutrons. The generator has been designed to be easily repaired and modified. The unit requires no additional equipment for operation or measurement of output

  7. Intense ion beam generator

    International Nuclear Information System (INIS)

    Humphries, S. Jr.; Sudan, R.N.

    1977-01-01

    Methods and apparatus for producing intense megavolt ion beams are disclosed. In one embodiment, a reflex triode-type pulsed ion accelerator is described which produces ion pulses of more than 5 kiloamperes current with a peak energy of 3 MeV. In other embodiments, the device is constructed so as to focus the beam of ions for high concentration and ease of extraction, and magnetic insulation is provided to increase the efficiency of operation

  8. High efficiency focus neutron generator

    Science.gov (United States)

    Sadeghi, H.; Amrollahi, R.; Zare, M.; Fazelpour, S.

    2017-12-01

    In the present paper, the new idea to increase the neutron yield of plasma focus devices is investigated and the results are presented. Based on many studies, more than 90% of neutrons in plasma focus devices were produced by beam target interactions and only 10% of them were due to thermonuclear reactions. While propounding the new idea, the number of collisions between deuteron ions and deuterium gas atoms were increased remarkably well. The COMSOL Multiphysics 5.2 was used to study the given idea in the known 28 plasma focus devices. In this circumstance, the neutron yield of this system was also obtained and reported. Finally, it was found that in the ENEA device with 1 Hz working frequency, 1.1 × 109 and 1.1 × 1011 neutrons per second were produced by D-D and D-T reactions, respectively. In addition, in the NX2 device with 16 Hz working frequency, 1.34 × 1010 and 1.34 × 1012 neutrons per second were produced by D-D and D-T reactions, respectively. The results show that with regards to the sizes and energy of these devices, they can be used as the efficient neutron generators.

  9. 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 ...

  10. Fusion neutron detector calibration using a table-top laser generated plasma neutron source

    International Nuclear Information System (INIS)

    Hartke, R.; Symes, D.R.; Buersgens, F.; Ruggles, L.E.; Porter, J.L.; Ditmire, T.

    2005-01-01

    Using a high intensity, femtosecond laser driven neutron source, a high-sensitivity neutron detector was calibrated. This detector is designed for observing fusion neutrons at the Z accelerator in Sandia National Laboratories. Nuclear fusion from laser driven deuterium cluster explosions was used to generate a clean source of nearly monoenergetic 2.45 MeV neutrons at a well-defined time. This source can run at 10 Hz and was used to build up a clean pulse-height spectrum on scintillating neutron detectors giving a very accurate calibration for neutron yields at 2.45 MeV

  11. Neutron detection time distributions of multisphere LiI detectors and AB rem meter at a 20 MeV electron linac

    International Nuclear Information System (INIS)

    Liu, J.C.; Rokni, S.; Vylet, V.; Arora, R.; Semones, E.; Justus, A.

    1997-01-01

    Neutron detection time distribution is an important factor for the dead-time correction for moderator type neutron detectors used in pulsed radiation fields. Measurements of the neutron detection time distributions of multisphere LiL detectors (2''3'' , 5'', 8'', 10'' and 12'' in diameter) and an AB rem meter were made inside an ANL 20 MeV electron linac room. Calculations of the neutron detection time distributions were also made using Monte Carlo codes. The first step was to calculate the neutron energy spectra at the target and detector positions, using a coupled EGS4-MORSE code with a giant-resonant photoneutron generation scheme. The calculated detector spectrum was found in agreement with the multisphere measurements. Then, neutrons hitting the detector surface were scored as a function of energy and the travel time in the room using MCNP. Finally, the above neutron fluence as a function of energy and travel time was used as the source term, and the neutrons detected by 6 Li or 10 B in the sensor were scored as a function of detection time for each detector using MCNP. The calculations of the detection time distributions agree with the measurements. The results also show that the detection time distributions of detectors with large moderators depend mainly on the moderator thickness and neutron spectrum. However, for small detectors, the neutron travel time in the field is also crucial. Therefore, all four factors (neutron spectrum, neutron travel time in the field, detector moderator thickness and detector response function) may play inter-related roles in the detection time distribution of moderator type detectors. (Author)

  12. Intense neutron source facility for the fusion energy program

    International Nuclear Information System (INIS)

    Armstrong, D.D.; Emigh, C.R.; Meier, K.L.; Meyer, E.A.; Schneider, J.D.

    1975-01-01

    The intense neutron source is based on the ability of a supersonic flow of gas to dissipate an enormous quantity of heat generated in the neutron-producing target by multiple Coulomb collisions. A description is given of the principles involved in forming the supersonic jet, in forming the intense tritium-ion beam, in the vacuum systems, and in the tritium handling systems. An overview of the entire facility is included. It is believed that the facility can be operated with high reliability, ensuring a productive radiation damage program. (U.S.)

  13. The Sealed Tube Neutron Generator

    International Nuclear Information System (INIS)

    Tunnell, L.N.; Beyerle, A.; Durkee, R.; Headley, G.; Hurley, P.

    1992-01-01

    A Sealed Tube Neutron Generator (STNG) has been designed and tested at Special Technologies Laboratories (STL) in Santa Barbara, California. Unlike similar tubes that have been used for years in other applications, e.g., by the oil well logging industry, the present device was designed primarily to be part of the Associated Particle Imaging (API) system. Consequently, the size and quality of the neutron spot produced by the STNG is of primary importance. Results from initial measurements indicate that performance goals are satisfied

  14. Compact ion source neutron generator

    Science.gov (United States)

    Schenkel, Thomas; Persaud, Arun; Kapadia, Rehan; Javey, Ali; Chang-Hasnain, Constance; Rangelow, Ivo; Kwan, Joe

    2015-10-13

    A neutron generator includes a conductive substrate comprising a plurality of conductive nanostructures with free-standing tips and a source of an atomic species to introduce the atomic species in proximity to the free-standing tips. A target placed apart from the substrate is voltage biased relative to the substrate to ionize and accelerate the ionized atomic species toward the target. The target includes an element capable of a nuclear fusion reaction with the ionized atomic species to produce a one or more neutrons as a reaction by-product.

  15. The Los Alamos Intense Neutron Source

    International Nuclear Information System (INIS)

    Nebel, R.A.; Barnes, D.C.; Bollman, R.; Eden, G.; Morrison, L.; Pickrell, M.M.; Reass, W.

    1997-01-01

    The Intense Neutron Source (INS) is an Inertial Electrostatic Confinement (IEC) fusion device presently under construction at Los Alamos National Laboratory. It is designed to produce 10 11 neutrons per second steady-state using D-T fuel. Phase 1 operation of this device will be as a standard three grid IEC ion focus device. Expected performance has been predicted by scaling from a previous IEC device. Phase 2 operation of this device will utilize a new operating scheme, the Periodically Oscillating Plasma Sphere (POPS). This scheme is related to both the Spherical Reflect Diode and the Oscillating Penning Trap. With this type of operation the authors hope to improve plasma neutron production to about 10 13 neutrons/second

  16. Source characterization of Purnima Neutron Generator (PNG)

    International Nuclear Information System (INIS)

    Bishnoi, Saroj; Patel, T.; Paul, Ram K.; Sarkar, P.S.; Adhikari, P.S.; Sinha, Amar

    2011-01-01

    The use of 14.1 MeV neutron generators for the applications such as elemental analysis, Accelerated Driven System (ADS) study, fast neutron radiography requires the characterization of neutron source i.e neutron yield (emission rate in n/sec), neutron dose, beam spot size and energy spectrum. In this paper, a series of experiments carried out to characterize this neutron source. The neutron source has been quantified with neutron emission rate, neutron dose at various source strength and beam spot size at target position

  17. Neutron spectra characteristics for the intense neutron source, INS

    International Nuclear Information System (INIS)

    Battat, M.; Dierckx, R.; Emigh, C.R.

    1977-01-01

    The Intense Neutron Source, INS, facility is presently under construction at the Los Alamos Scientific Laboratory. Its purpose is to provide a broad base for research work related to the radiation effects produced by 14-MeV neutrons from a D-T burn of a fusion reactor. The INS facility produces a D-T burn-like reaction from the collision of an intense tritium-ion beam with a supersonic jet target of deuterium gas. The reaction produces a typical D-T 14-MeV neutron spectrum. By adding a fission blanket surrounding the D-T ''burn,'' the neutron spectral shape may be tailored to match almost perfectly the anticipated first-wall spectra from presently proposed fusion reactors. With a blanket in place, the total production of neutrons can be as large as 3 x 10 16 n/s and experimental volumes of the order of 1000 cm 3 can be available at flux levels greater than 0.6 x 10 14 n/cm 2 s

  18. Beam Loss in Linacs

    CERN Document Server

    Plum, M.A.

    2016-01-01

    Beam loss is a critical issue in high-intensity accelerators, and much effort is expended during both the design and operation phases to minimize the loss and to keep it to manageable levels. As new accelerators become ever more powerful, beam loss becomes even more critical. Linacs for H- ion beams, such as the one at the Oak Ridge Spallation Neutron Source, have many more loss mechanisms compared to H+ (proton) linacs, such as the one being designed for the European Spallation Neutron Source. Interesting H- beam loss mechanisms include residual gas stripping, H+ capture and acceleration, field stripping, black-body radiation and the recently discovered intra-beam stripping mechanism. Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H+ and H- accelerators. Machine protection systems play an important role in limiting the beam loss.

  19. System design of a proton linac for the neutron science project at Japan Atomic Energy Research Institute

    International Nuclear Information System (INIS)

    Hasegawa, Kazuo; Mizumoto, Motoharu; Ouchi, Nobuo; Honda, Yoichiro; Ino, Hiroshi

    1999-01-01

    The Japan Atomic Energy Research Institute has been proposing the Neutron Science Project (NSP). The NSP requires pulse and CW proton beams with an energy of 1.5 GeV and an average beam power up to 8MW. This paper describes design concepts and parameters of the linac. A front end part of the linac, which consists of RFQ, DTL and SDTL sections, uses normal conducting structures and a high energy part uses superconducting (SC) structures. The linac has two injector lines for the pulse and the CW modes, respectively, and the two lines merge at 7 MeV. The total linac length is approximately 900 m and most of the part (>75%) is the superconducting section. An equipartitioning design, which is a new idea to suppress an emittance growth for high power linacs, has been taken for the DTL, the SDTL and the SC sections. Compared with the conventional constant phase advance design scheme, the equipartitioning design scheme is proved to be a good approach to suppress the longitudinal emittance growth. (author)

  20. Neural stem cell sparing by linac based intensity modulated stereotactic radiotherapy in intracranial tumors

    International Nuclear Information System (INIS)

    Oehler, Julia; Brachwitz, Tim; Wendt, Thomas G; Banz, Nico; Walther, Mario; Wiezorek, Tilo

    2013-01-01

    Neurocognitive decline observed after radiotherapy (RT) for brain tumors in long time survivors is attributed to radiation exposure of the hippocampus and the subventricular zone (SVZ). The potential of sparing capabilities for both structures by optimized intensity modulated stereotactic radiotherapy (IMSRT) is investigated. Brain tumors were irradiated by stereotactic 3D conformal RT or IMSRT using m3 collimator optimized for PTV and for sparing of the conventional OARs (lens, retina, optic nerve, chiasm, cochlea, brain stem and the medulla oblongata). Retrospectively both hippocampi and SVZ were added to the list of OAR and their dose volume histograms were compared to those from two newly generated IMSRT plans using 7 or 14 beamlets (IMSRT-7, IMSRT-14) dedicated for optimized additional sparing of these structures. Conventional OAR constraints were kept constant. Impact of plan complexity and planning target volume (PTV) topography on sparing of both hippocampi and SVZ, conformity index (CI), the homogeneity index (HI) and quality of coverage (QoC) were analyzed. Limits of agreement were used to compare sparing of stem cell niches with either IMSRT-7 or IMSRT-14. The influence of treatment technique related to the topography ratio between PTV and OARs, realized in group A-D, was assessed by a mixed model. In 47 patients CI (p ≤ 0.003) and HI (p < 0.001) improved by IMSRT-7, IMSRT-14, QoC remained stable (p ≥ 0.50) indicating no compromise in radiotherapy. 90% of normal brain was exposed to a significantly higher dose using IMSRT. IMSRT-7 plans resulted in significantly lower biologically effective doses at all four neural stem cell structures, while contralateral neural stem cells are better spared compared to ipsilateral. A further increase of the number of beamlets (IMSRT-14) did not improve sparing significantly, so IMSRT-7 and IMSRT-14 can be used interchangeable. Patients with tumors contacting neither the subventricular zone nor the cortex benefit

  1. Neutron generator ion source pulser

    International Nuclear Information System (INIS)

    Peelman, H.E.

    1987-01-01

    This patent describes, for use with a pulsed neutron generator in a logging tool lowered in a borehole, a pulsed high voltage source having an output terminal adapted to be connected to pulse neutron generator. The power supply comprises: (a) high voltage supply means; (b) field effect transistor means comprising at least a pair of field effect transistors serially connected between the high voltage supply means and ground; (c) an output terminal between the two transistors of the field effect transistor means, the output terminal adapted to be connected by a conductor to provide pulsed high voltage to a neutron generator; (d) control pulse forming means connected to the gates of the respective two transistors, the pulse forming means forming control pulses selectively switching the transistors off and on in timed sequence to thereby connect the output terminal to the high voltage supply means, and (e) diode means connected to the gates of the transistors to limit gate voltage for operation of the transistors

  2. Present status of the ETL LINAC facility

    International Nuclear Information System (INIS)

    Suzuki, Ryoichi; Mikado, Tomohisa; Ohgaki, Hideaki

    1993-01-01

    The ETL LINAC has been operated for the beam injection to the storage rings NIJI-II, III, IV, and TERAS, and for the generation of an intense slow positron beam. The status of the ETL LINAC on the operations, the maintenances, and the improvements is described. (author)

  3. High duty factor Plasma Generator for CERN’s Superconducting Proton Linac

    CERN Document Server

    Lettry, J; Scrivens, R; Chaudet, E; Faircloth, D; Favre, G; Geisser, JM; Kuchler, D; Mathot, S; Midttun, O; Paoluzzi, M; Schmitzer, C; Steyaert, D

    2010-01-01

    CERN’s Linac4 is a 160 MeV linear accelerator currently under construction. It will inject negatively charged hydrogen ions into CERN’s PS-Booster. Its ion source is a non-cesiated RF driven H- volume source directly inspired from the one of DESY and is aimed to deliver pulses of 80 mA of H- during 0.4 ms at a 2 Hz repetition rate. The Superconducting Proton Linac (SPL) project is part of the luminosity upgrade of the LHC, it consists of an extension of Linac4 up to 5 GeV and is foreseen to deliver protons to a future 50 GeV Synchrotron (PS2). For the SPL high power option (HP-SPL), the ion source would deliver pulses of 80 mA of H- during 1.2 ms and operate at a 50 Hz repetition rate. This significant upgrade motivates the design of the new water cooled plasma generator presented in this paper. Its engineering is based on the results of a finite element thermal study of the Linac4 H- plasma generator that identified critical components and thermal barriers. A cooling system is proposed which achieves the...

  4. Artificial neural network for the determination of neutron spectra in the bunker of a Linac of 18 MV

    International Nuclear Information System (INIS)

    Banuelos F, A.; Borja H, C. G.; Valero L, C.; Guzman G, K. A.; Hernandez D, V. M.; Vega C, H. R.

    2011-11-01

    The neutron spectrum and equivalent of environmental dose H(10) were calculated for a radiotherapy room in 16 punctual detectors, 15 inside of and 1 outside of the same one. The calculations were carried out with the Monte Carlo method and with the code MCNP5 for a generic room model with a Linac of 18 MV, obtaining this way 16 spectra with 47 intervals of energy class, starting from these spectra the values of H(10) were calculated. On the other hand, an artificial neural network was designed and trained to determine the spectra by neutrons in 15 different locations inside the radiotherapy room starting from the value of H(10) in the detector 16 located in the exterior of the room, using as training data the spectra and calculated dose by neutrons, of which a medium quadratic error was obtained (m se) in the adjustment between the objective data and the exit data of m se=1E(-8). The results demonstrate that the use of the artificial intelligence as technique is an useful tool in the spectrometry and dosimetry of neutrons, since it simplifies the characterization process of neutron fields in radiotherapy rooms without the use of spectrometry systems, and that once the energy distribution of the neutrons produced by the Linac is known and the corresponding doses be calculated H(10), they can take the appropriate cautions for the security patient in treatment as well as for the personnel in the room. (Author)

  5. PNG-300 a nanosecond pulsed neutron generator

    International Nuclear Information System (INIS)

    Sztaricskai, T.; Vasvary, L.; Petoe, G.C.; Devkin, B.V.

    1985-01-01

    The design and operation of a nanosecond-pulse neutron generator is reported. It was constructed for the measurement of prompt neutron and gamma radiation in experimental studies of fast neutron reactions by time of flight techniques. The acceleration voltage is 300 kV and the total resolution of the generator-neutron spectrometer system is 2 ns. The ion-optical system, the vacuum system and the control of the neutron generator is described in detail. The equipment was used for prompt neutron and gamma radiation induced in construction materials. (R.P.)

  6. Beam monitoring system for intense neutron source

    International Nuclear Information System (INIS)

    Tron, A.M.

    2001-01-01

    Monitoring system realizing novel principle of operation and allowing to register a two-dimensional beam current distribution within entire aperture (100...200 mm) of ion pipe for a time in nanosecond range has been designed and accomplished for beam control of the INR intense neutron source, for preventing thermo-mechanical damage of its first wall. Key unit of the system is monitor of two-dimensional beam current distribution, elements of which are high resistant to heating by the beam and to radiation off the source. The description of the system and monitor are presented. Implementation of the system for the future sources with more high intensities are discussed. (author)

  7. Experiment of Neutron Generation by Using Prototype D-D Neutron Generator

    International Nuclear Information System (INIS)

    Kim, In Jung; Kim, Suk Kwon; Park, Chang Su; Jung, Nam Suk; Jung, Hwa Dong; Park, Ji Young; Hwang, Yong Seok; Choi, H.D.

    2005-01-01

    Experiment of neutron generation was performed by using a prototype D-D neutron generator. The characteristics of D-D neutron generation in drive-in target was studied. The increment of neutron yield by increasing ion beam energy was investigated, too

  8. Neutron production enhancements for the Intense Pulsed Neutron Source.

    Energy Technology Data Exchange (ETDEWEB)

    Iverson, E. B.

    1999-01-04

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

  9. Neutron production enhancements for the Intense Pulsed Neutron Source

    International Nuclear Information System (INIS)

    Iverson, E. B.

    1999-01-01

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

  10. Compact neutron generators for environmental recovery applications

    International Nuclear Information System (INIS)

    Leung, K. N.; Firestone, R. B.; Lou, T. P.; Reijonen, J.; Vujic, J. Lj.

    2002-01-01

    New generations of compact neutron sources are being developed at the Lawrence Berkeley National Laboratory (LBNL). The D-D or D-T neutron generators can be used to perform precise elemental analysis by Prompt Gamma-Ray Activation Analysis (PGAA) in place of a nuclear reactor. The neutron generators will be composed of an ion source, from which a 1.5 A deuterium beam will be extracted and accelerated to about 150 keV onto a target loaded with deuterium. Based on the D-D nuclear reaction, the neutron generator will yield approximately 10 12 n/s (10 14 n/s for D-T reaction). With this neutron output, thermal and cold neutron fluxes of 10 7 n/s cm 2 and 6 x 10 6 n/s cm 2 have been estimated using neutron moderators designed by the neutron transport simulation code MCNP. (author)

  11. The secondary neutron sources for generation of particular neutron fluxes

    International Nuclear Information System (INIS)

    Tracz, G.

    2007-07-01

    The foregoing paper presents the doctor's thesis entitled '' The secondary neutron sources for generation of particular neutron fluxes ''. Two secondary neutron sources have been designed, which exploit already existing primary sources emitting neutrons of energies different from the desired ones. The first source is devoted to boron-neutron capture therapy (BNCT). The research reactor MARIA at the Institute of Atomic Energy in Swierk (Poland) is the primary source of the reactor thermal neutrons, while the secondary source should supply epithermal neutrons. The other secondary source is the pulsed source of thermal neutrons that uses fast 14 MeV neutrons from a pulsed generator at the Institute of Nuclear Physics PAN in Krakow (Poland). The physical problems to be solved in the two mentioned cases are different. Namely, in order to devise the BNCT source the initial energy of particles ought to be increased, whilst in the other case the fast neutrons have to be moderated. Slowing down of neutrons is relatively easy since these particles lose energy when they scatter in media; the most effective moderators are the materials which contain light elements (mostly hydrogen). In order to increase the energy of neutrons from thermal to epithermal (the BNCT case) the so-called neutron converter should be exploited. It contains a fissile material, 235 U. The thermal neutrons from the reactor cause fission of uranium and fast neutrons are emitted from the converter. Then fissile neutrons of energy of a few MeV are slowed down to the required epithermal energy range. The design of both secondary sources have been conducted by means of Monte Carlo simulations, which have been carried out using the MCNP code. In the case of the secondary pulsed thermal neutron source, some of the calculated results have been verified experimentally. (author)

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

    Directory of Open Access Journals (Sweden)

    A Ghasemi

    2015-01-01

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

  13. Use of a newly developed active thermal neutron detector for in-phantom measurements in a medical LINAC

    Energy Technology Data Exchange (ETDEWEB)

    Bodogni, R.; Sanchez-Doblado, F.; Pola, A.; Gentile, A.; Esposito, A.; Gomez-ros, J. M.; Pressello, M. C.; Lagares, J. I.; Terron, J. A.; Gomez, F.

    2013-07-01

    In this work a newly developed active thermal neutron detector, based on a solid state analog device, was used to determine the thermal neutron fluence in selected positions of a simplified human phantom undergoing radiotherapy with a 15 MV LINAC. The results are compared with TLD, the predictions from a Monte Carlo simulation and with measurements indirectly performed with a digital device, located far from the phantom, inside the treatment room. In this work only TLD comparison is presented. Since active neutron instruments are usually affected by systematic deviations when used in a pulsed field with large photon background, the new detector offered in this work may represent an innovative and useful tool for neutron evaluations in accelerator-based radiotherapy. (Author)

  14. Trial production of hyper-thermal neutron generator for Neutron Capture Therapy (NCT) and its radiation properties

    International Nuclear Information System (INIS)

    Sakurai, Yoshinori; Kobayashi, Toru

    1999-01-01

    In NCT, it was at first important to give a cancer portion to radiation dose required for its recovery. By finding out that whole cross-section of water comprising of a living body decreased monotonously with increase of neutron energy from about 100 barn against thermal neutron, became about 40 barn at about 0.5 eV and kept constant to 40 barn till at about 100 eV, application of thermal neutron shifted to higher temperature side, called Hyper thermal neutron, to NCT is proposed. The Hyper thermal neutron radiation can be expected to have similar controllability to that of the thermal neutron radiation. In 1977 fiscal year, a trial Hyper thermal neutron generator was produced on a base of up-to-date investigation results. As a part of property evaluation of the generator, evaluation of energy spectra in the Hyper thermal neutron generated at LINAC by TOF was conducted to confirm shift of the spectra to high temperature side. And, a Fantom experiment at KUR heavy water neutron radiation facility was also conducted to confirm effect of improvement in deep portion dose distribution. (G.K.)

  15. Radiation protection studies for a high-power 160 MeV proton linac

    CERN Document Server

    Mauro, Egidio

    2009-01-01

    CERN is presently designing a new chain of accelerators to replace the present Proton Synchrotron (PS) complex: a 160 MeV room-temperature H− linac (Linac4) to replace the present 50 MeV proton linac injector, a 3.5 GeV Superconducting Proton Linac (SPL) to replace the 1.4 GeV PS Booster (PSB) and a 50 GeV synchrotron (named PS2) to replace the 26 GeV PS. Linac4 has been funded and the civil engineering work started in October 2008, whilst the SPL is in an advanced stage of design. Beyond injecting into the future 50 GeV PS, the ultimate goal of the SPL is to generate a 4 MW beam for the production of intense neutrino beams. The radiation protection design is driven by the latter requirement. This work summarizes the radiation protection studies conducted for Linac4. FLUKA Monte Carlo simulations, complemented by analytical estimates, were performed to evaluate the propagation of neutrons through the waveguide, ventilation and cable ducts placed along the accelerator, to estimate the radiological impact of ...

  16. submitter Radiation Protection Studies for CERN LINAC4/SPL Accelerator Complex

    CERN Document Server

    Mauro, Egidio; Silari, Marco

    2009-01-01

    CERN is presently designing a new chain of accelerators to replace the present Proton Synchrotron (PS) complex: a 160 MeV room-temperature H$^-$ linac (Linac4) to replace the present 50 MeV proton linac injector, a 3.5 GeV Superconducting Proton Linac (SPL) to replace the 1.4 GeV PS booster (PSB) and a 50 GeV synchrotron (named PS2) to replace the 26 GeV PS. Linac4 has been funded and the civil engineering work started in October 2008, whilst the SPL is in an advanced stage of design. Beyond injecting into the future 50 GeV PS, the ultimate goal of the SPL is to generate a 4 MW beam for the production of intense neutrino beams. The radiation protection design is driven by the latter requirement. This thesis summarizes the radiation protection studies conducted for Linac4. FLUKA Monte Carlo simulations, complemented by analytical estimates, were performed 1) to evaluate the propagation of neutrons through the waveguide, ventilation and cable ducts placed along the accelerator, 2) to estimate the radiological i...

  17. Solid-state pulse modulator using Marx generator for a medical linac electron-gun

    Science.gov (United States)

    Lim, Heuijin; Hyeok Jeong, Dong; Lee, Manwoo; Lee, Mujin; Yi, Jungyu; Yang, Kwangmo; Ro, Sung Chae

    2016-04-01

    A medical linac is used for the cancer treatment and consists of an accelerating column, waveguide components, a magnetron, an electron-gun, a pulse modulator, and an irradiation system. The pulse modulator based on hydrogen thyratron-switched pulse-forming network is commonly used in linac. As the improvement of the high power semiconductors in switching speed, voltage rating, and current rating, an insulated gate bipolar transistor has become the more popular device used for pulsed power systems. We propose a solid-state pulse modulator to generator high voltage by multi-stacked storage-switch stages based on the Marx generator. The advantage of our modulator comes from the use of two semiconductors to control charging and discharging of the storage capacitor at each stage and it allows to generate the pulse with various amplitudes, widths, and shapes. In addition, a gate driver for two semiconductors is designed to reduce the control channels and to protect the circuits. It is developed for providing the pulsed power to a medical linac electron-gun that requires 25 kV and 1 A as the first application. In order to improve the power efficiency and achieve the compactness modulator, a capacitor charging power supply, a Marx pulse generator, and an electron-gun heater isolated transformer are constructed and integrated. This technology is also being developed to extend the high power pulsed system with > 1 MW and also other applications such as a plasma immersed ion implantation and a micro pulse electrostatic precipitator which especially require variable pulse shape and high repetition rate > 1 kHz. The paper describes the design features and the construction of this solid-state pulse modulator. Also shown are the performance results into the linac electron-gun.

  18. Solid-state pulse modulator using Marx generator for a medical linac electron-gun

    International Nuclear Information System (INIS)

    Lim, Heuijin; Jeong, Dong Hyeok; Lee, Manwoo; Lee, Mujin; Yi, Jungyu; Yang, Kwangmo; Ro, Sung Chae

    2016-01-01

    A medical linac is used for the cancer treatment and consists of an accelerating column, waveguide components, a magnetron, an electron-gun, a pulse modulator, and an irradiation system. The pulse modulator based on hydrogen thyratron-switched pulse-forming network is commonly used in linac. As the improvement of the high power semiconductors in switching speed, voltage rating, and current rating, an insulated gate bipolar transistor has become the more popular device used for pulsed power systems. We propose a solid-state pulse modulator to generator high voltage by multi-stacked storage-switch stages based on the Marx generator. The advantage of our modulator comes from the use of two semiconductors to control charging and discharging of the storage capacitor at each stage and it allows to generate the pulse with various amplitudes, widths, and shapes. In addition, a gate driver for two semiconductors is designed to reduce the control channels and to protect the circuits. It is developed for providing the pulsed power to a medical linac electron-gun that requires 25 kV and 1 A as the first application. In order to improve the power efficiency and achieve the compactness modulator, a capacitor charging power supply, a Marx pulse generator, and an electron-gun heater isolated transformer are constructed and integrated. This technology is also being developed to extend the high power pulsed system with > 1 MW and also other applications such as a plasma immersed ion implantation and a micro pulse electrostatic precipitator which especially require variable pulse shape and high repetition rate > 1 kHz. The paper describes the design features and the construction of this solid-state pulse modulator. Also shown are the performance results into the linac electron-gun

  19. Production of radionuclides by 14 MeV neutron generator

    International Nuclear Information System (INIS)

    Alfassi, Z.B.

    1983-01-01

    Due to the short half-lives of these nuclides they have to be produced in situ or at least not far from the place of use. The cost of 14 MeV neutron generators have been compared with the typical middle-sized cyclotrons and it was found that the capital costs are much lower in the case of neutron generators. This is the main reason for the availability of 14 MeV neutron generators in many scientific institutes compared to the scarcity of cyclotrons. Lately, the use of 14 MeV neutrons for cancer therapy was studied in several medical centers. A number of hospitals and cancer research centers have high intensity 14 MeV neutron generators for this purpose. The advantages of using short-lived in-house produced radionuclides suggest the use of the available 14 MeV neutron generators for biological studies and in medical diagnosis. 14 MeV neutron generators can be used to produce some of the medically useful radionuclides, such as /sup 18/F, /sup 80/Br, /sup 199m/Hg, and others. However, the amount required for medicine can only be prepared by the new high intensity neutron generators, used for neutron therapy and not by the smaller ones, commonly used in university laboratories (--10/sup 11/ n/sec). On the other hand, these relatively small neutron generators can be used for the preparation of radionuclides for biological studies. They facilitate the study of metabolism of elements for which radionuclides cannot be usually purchased due to short half-lives or the high price of the long-lived ones, such as /sup 34m/Cl, /sup 18/F, /sup 28,29/Al, /sup 27/Mg, and others. An example is the work done on the fate of Al and Mg in rats using /sup 28/Al and /sup 27/Mg./sup 13/

  20. Method for stabilizing beam intensity and energy in the SPring-8 linac

    International Nuclear Information System (INIS)

    Asaka, T.; Kawashima, Y.; Takashima, T.; Kobayashi, T.; Ohshima, T.; Hanaki, H.

    2004-01-01

    In any electron accelerator facilities, radio frequencies (RF) for a linear accelerator and a circular accelerator that includes a booster synchrotron ring and a storage ring are completely different. There is not necessarily a sub-harmonic relation of two RFs between a linear accelerator and a circular accelerator. It is, however, indispensable to obtain a synchronous relation between both RFs and the timing of the gun trigger signal with the increasing beam current and shortening of beam time width from an electron gun in a linear accelerator. For a synchronous timing system in any electron accelerator facilities, there is no choice but to assemble a complicated system with the frequency dividers and multipliers in order to realize the synchronous relation between both RFs and the gun trigger signal. To simplify the complicated synchronous timing system, we have developed a new synchronization method for the RFs of both linear and circular accelerators. The new synchronization system has been installed into the synchrotron radiation facility, SPring-8 (Super Photon ring 8 GeV), which consists of a 1-GeV linac, an 8-GeV booster synchrotron and an 8-GeV storage ring. A 2856 MHz RF for the 1-GeV linac was generated by the 508.58 MHz RF of the 8-GeV storage ring with the new synchronous timing system, and the emission and acceleration under the condition of the shortening the beam time width in the linac was carried out. Since the synchronous relation between both the RFs and the gun trigger signal was realized by using the new synchronous timing system, the time jitter between the gun trigger signal and the RF phase of 2856 MHz was significantly reduced and resulted in beam energy stabilization. The new synchronous timing system has been used for usual beam operations at SPring-8. This timing system has achieved time jitters of 3.5 ps (rms) and beam energy stability of 0.009% (rms) under the condition of completely synchronized two RFs and the gun trigger signal

  1. Gas target neutron generator studies

    International Nuclear Information System (INIS)

    Chatoorgoon, V.

    1978-01-01

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

  2. A tunable, linac based, intense, broad-band THz source forpump-probe experiments

    Energy Technology Data Exchange (ETDEWEB)

    Schmerge, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Adolphsen, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Corbett, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Dolgashev, V. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Durr, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fazio, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fisher, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Frisch, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Gaffney, K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Guehr, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hastings, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hettel, B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hoffmann, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hogan, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Holtkamp, N. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Huang, X. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Huang, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Kirchmann, P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); LaRue, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Limborg, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lindenberg, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Loos, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Maxwell, T. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Nilsson, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Raubenheimer, T. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Reis, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Ross, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Shen, Z. -X. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stupakov, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tantawi, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tian, K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Wu, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Xiang, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Yakimenko, V. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-02-02

    We propose an intense THz source with tunable frequency and bandwidth that can directly interact with the degrees of freedom that determine the properties of materials and thus provides a new tool for controlling and directing these ultrafast processes as well as aiding synthesis of new materials with new functional properties. This THz source will broadly impact our understanding of dynamical processes in matter at the atomic-scale and in real time. Established optical pumping schemes using femtosecond visible frequency laser pulses for excitation are extended into the THz frequency regime thereby enabling resonant excitation of bonds in correlated solid state materials (phonon pumping), to drive low energy electronic excitations, to trigger surface chemistry reactions, and to all-optically bias a material with ultrashort electric fields or magnetic fields. A linac-based THz source can supply stand-alone experiments with peak intensities two orders of magnitude stronger than existing laser-based sources, but when coupled with atomic-scale sensitive femtosecond x-ray probes it opens a new frontier in ultrafast science with broad applications to correlated materials, interfacial and liquid phase chemistry, and materials in extreme conditions.

  3. Status of the intense pulsed neutron source

    International Nuclear Information System (INIS)

    Brown, B.S.; Carpenter, J.M.; Crawford, R.K.; Rauchas, A.V.; Schulke, A.W.; Worlton, T.G.

    1989-01-01

    Since 1981 the average proton currents at IPNS has increased substantially. The reliability has averaged 91%. The moderator has changed from a room temperature polyethylene to cryogenic methane. This report details progress made at IPNS (Intense Pulsed Neutron Source) during the last two years. The topics discussed are the operating status of the accelerator systems, other accelerator activities (such as, IPNS participation in SDI), instrumentation operating at IPNS, chopper development at IPNS, data acquisition, Booster target, moderators and examples of recent scientific results. The ever increasing instrument capability, the Booster target and the very active involvement with the scientific user community guarantees a productive scientific future at IPNS. 9 figs., 3 tabs

  4. Matching the laser generated p bunch into a crossbar-H drift tube linac

    Science.gov (United States)

    Almomani, A.; Droba, M.; Ratzinger, U.; Hofmann, I.

    2012-05-01

    Proton bunches with energies up to 30 MeV have been measured at the PHELIX laser. Because of the laser-plasma interactions at a power density of about 4×1019W/cm2, a total yield of 1.5×1013protons was produced. For the reference energy of 10 MeV, the yield within ±0.5MeV was exceeding 1010protons. The important topic for a further acceleration of the laser generated bunch is the matching into the acceptance of an rf accelerator stage. With respect to the high space charge forces and the transit energy range, only drift tube linacs seem adequate for this purpose. A crossbar H-type (CH) cavity was chosen as the linac structure. Optimum emittance values for the linac injection are compared with the available laser generated beam parameters. Options for beam matching into a CH structure by a pulsed magnetic solenoid and by using the simulation codes LASIN and LORASR are presented.

  5. Matching the laser generated p bunch into a crossbar-H drift tube linac

    Directory of Open Access Journals (Sweden)

    A. Almomani

    2012-05-01

    Full Text Available Proton bunches with energies up to 30 MeV have been measured at the PHELIX laser. Because of the laser-plasma interactions at a power density of about 4×10^{19}  W/cm^{2}, a total yield of 1.5×10^{13}  protons was produced. For the reference energy of 10 MeV, the yield within ±0.5  MeV was exceeding 10^{10}  protons. The important topic for a further acceleration of the laser generated bunch is the matching into the acceptance of an rf accelerator stage. With respect to the high space charge forces and the transit energy range, only drift tube linacs seem adequate for this purpose. A crossbar H-type (CH cavity was chosen as the linac structure. Optimum emittance values for the linac injection are compared with the available laser generated beam parameters. Options for beam matching into a CH structure by a pulsed magnetic solenoid and by using the simulation codes LASIN and LORASR are presented.

  6. An improved permanent magnet quadrupole design with larger good field region for high intensity proton linacs

    Energy Technology Data Exchange (ETDEWEB)

    Mathew, Jose V., E-mail: josev.mathew@gmail.com; Rao, S.V.L.S.; Krishnagopal, S.; Singh, P.

    2013-11-01

    The Low Energy High Intensity Proton Accelerator (LEHIPA), being developed at the Bhabha Atomic Research Centre (BARC) will produce a 20 MeV, 30 mA, continuous wave (CW) proton beam. At these low velocities, space-charge forces dominate, and could lead to larger beam sizes and beam halos. Hence in the design of the focusing lattice of the LEHIPA drift tube linac (DTL) using permanent magnet quadrupoles (PMQs), a larger good field region is preferred. Here we study, using the two dimensional (2D) and three dimensional (3D) simulation codes PANDIRA and RADIA, four different types of cylindrical PMQ designs: 16-segment trapezoidal Halbach configuration, bullet-nosed geometry and 8- and 16-segment rectangular geometries. The trapezoidal Halbach geometry is used in a variety of accelerators since it provides very high field gradients in small bores, while the bullet-nosed geometry, which is a combination of the trapezoidal and rectangular designs, is used in some DTLs. This study shows that a larger good field region is possible in the 16-segment rectangular design as compared to the Halbach and bullet-nosed designs, making it more attractive for high-intensity proton linacs. An improvement in good-field region by ∼16% over the Halbach design is obtained in the optimized 16-segment rectangular design, although the field gradient is lower by ∼20%. Tolerance studies show that the rectangular segment PMQ design is substantially less sensitive to the easy axis orientation errors and hence will be a better choice for DTLs. -- Highlights: • An improved permanent magnet quadrupole (PMQ) design with larger good field region is proposed. • We investigate four PMQ designs, including the widely used Halbach and bullet nosed designs. • Analytical calculations are backed by 2D as well as 3D numerical solvers, PANDIRA and RADIA. • The optimized 16 segment rectangular PMQ design is identified to exhibit the largest good field region. • The effect of easy axis orientation

  7. An improved permanent magnet quadrupole design with larger good field region for high intensity proton linacs

    International Nuclear Information System (INIS)

    Mathew, Jose V.; Rao, S.V.L.S.; Krishnagopal, S.; Singh, P.

    2013-01-01

    The Low Energy High Intensity Proton Accelerator (LEHIPA), being developed at the Bhabha Atomic Research Centre (BARC) will produce a 20 MeV, 30 mA, continuous wave (CW) proton beam. At these low velocities, space-charge forces dominate, and could lead to larger beam sizes and beam halos. Hence in the design of the focusing lattice of the LEHIPA drift tube linac (DTL) using permanent magnet quadrupoles (PMQs), a larger good field region is preferred. Here we study, using the two dimensional (2D) and three dimensional (3D) simulation codes PANDIRA and RADIA, four different types of cylindrical PMQ designs: 16-segment trapezoidal Halbach configuration, bullet-nosed geometry and 8- and 16-segment rectangular geometries. The trapezoidal Halbach geometry is used in a variety of accelerators since it provides very high field gradients in small bores, while the bullet-nosed geometry, which is a combination of the trapezoidal and rectangular designs, is used in some DTLs. This study shows that a larger good field region is possible in the 16-segment rectangular design as compared to the Halbach and bullet-nosed designs, making it more attractive for high-intensity proton linacs. An improvement in good-field region by ∼16% over the Halbach design is obtained in the optimized 16-segment rectangular design, although the field gradient is lower by ∼20%. Tolerance studies show that the rectangular segment PMQ design is substantially less sensitive to the easy axis orientation errors and hence will be a better choice for DTLs. -- Highlights: • An improved permanent magnet quadrupole (PMQ) design with larger good field region is proposed. • We investigate four PMQ designs, including the widely used Halbach and bullet nosed designs. • Analytical calculations are backed by 2D as well as 3D numerical solvers, PANDIRA and RADIA. • The optimized 16 segment rectangular PMQ design is identified to exhibit the largest good field region. • The effect of easy axis orientation

  8. Spectra and neutron dose of an 18 MV Linac using two geometric models of the head

    International Nuclear Information System (INIS)

    Barrera, M. T.; Pino, F.; Barros, H.; Sajo-Bohus, L.; Davila, J.; Salcedo, E.; Vega C, H. R.; Benites R, J. L.

    2015-10-01

    Full text: Using the Monte Carlo method, by MCNP5 code, simulations were performed with different source terms and 2 geometric models of the head to obtain spectra in energy, flow and doses of photo-neutrons at different positions on the stretcher and in the radiotherapy room. The simplest model was a spherical shell of tungsten; the second was the complete model of a heterogeneous head of an accelerator Varian ix. In both models Tosi function was used as a source term. In addition, for the second model Sheikh-Bagheri distribution was used for photons and photo-neutrons were generated. Also in both models the radiotherapy room of Gurve group of the Teaching Medical Center La Trinidad was included, which is equipped with an accelerator Varian Clinic 2100. In this Center passive detectors PADC (Cr-39) were irradiated with neutron converters, with 18 MeV photons radiation. The measured neutron flow was compared with that obtained with Monte Carlo calculations. The Monte Carlo flows are similar to those measured at the isocenter. The simplest model underestimates the neutron flow compared with the calculated flows with the heterogeneous model of the head. (Author)

  9. Assessing neutron generator output using neutron activation of silicon

    International Nuclear Information System (INIS)

    Kehayias, Pauli M.; Kehayias, Joseph J.

    2007-01-01

    D-T neutron generators are used for elemental composition analysis and medical applications. Often composition is determined by examining elemental ratios in which the knowledge of the neutron flux is unnecessary. However, the absolute value of the neutron flux is required when the generator is used for neutron activation analysis, to study radiation damage to materials, to monitor the operation of the generator, and to measure radiation exposure. We describe a method for absolute neutron output and flux measurements of low output D-T neutron generators using delayed activation of silicon. We irradiated a series of silicon oxide samples with 14.1 MeV neutrons and counted the resulting gamma rays of the 28 Al nucleus with an efficiency-calibrated detector. To minimize the photon self-absorption effects within the samples, we used a zero-thickness extrapolation technique by repeating the measurement with samples of different thicknesses. The neutron flux measured 26 cm away from the tritium target of a Thermo Electron A-325 D-T generator (Thermo Electron Corporation, Colorado Springs, CO) was 6.2 x 10 3 n/s/cm 2 ± 5%, which is consistent with the manufacturer's specifications

  10. Assessing neutron generator output using neutron activation of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Kehayias, Pauli M. [Body Composition Laboratory, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111 (United States); Kehayias, Joseph J. [Body Composition Laboratory, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111 (United States)]. E-mail: joseph.kehayias@tufts.edu

    2007-08-15

    D-T neutron generators are used for elemental composition analysis and medical applications. Often composition is determined by examining elemental ratios in which the knowledge of the neutron flux is unnecessary. However, the absolute value of the neutron flux is required when the generator is used for neutron activation analysis, to study radiation damage to materials, to monitor the operation of the generator, and to measure radiation exposure. We describe a method for absolute neutron output and flux measurements of low output D-T neutron generators using delayed activation of silicon. We irradiated a series of silicon oxide samples with 14.1 MeV neutrons and counted the resulting gamma rays of the {sup 28}Al nucleus with an efficiency-calibrated detector. To minimize the photon self-absorption effects within the samples, we used a zero-thickness extrapolation technique by repeating the measurement with samples of different thicknesses. The neutron flux measured 26 cm away from the tritium target of a Thermo Electron A-325 D-T generator (Thermo Electron Corporation, Colorado Springs, CO) was 6.2 x 10{sup 3} n/s/cm{sup 2} {+-} 5%, which is consistent with the manufacturer's specifications.

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

    International Nuclear Information System (INIS)

    Komeda, Osamu; Mori, Yoshitaka; Nishimura, Yasuhiko

    2013-01-01

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

  12. NEUTRON AND PHOTON DOSE MAPPING OF A DD NEUTRON GENERATOR.

    Science.gov (United States)

    Metwally, Walid A; Taqatqa, Osama A; Ballaith, Mohammed M; Chen, Allan X; Piestrup, Melvin A

    2017-11-01

    Neutron generators are an excellent tool that can be effectively utilized in educational institutions for applications such as neutron activation analysis, neutron radiography, and profiling and irradiation effects. For safety purposes, it is imperative that appropriate measures are taken in order to minimize the radiation dose from such devices to the operators, students and the public. This work presents the simulation and measurement results for the neutron and photon dose rates in the vicinity of the neutron generator installed at the University of Sharjah. A very good agreement is found between the simulated and measured dose rates. All of the public dose constraints were found to be met. The occupational dose constraint was also met after imposing a 200 cm no entry zone around the generator room. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Compact neutron generator development and applications

    International Nuclear Information System (INIS)

    Leung, Ka-Ngo; Reijonen, Jani; Gicquel, Frederic; Hahto, Sami; Lou, Tak-Pui

    2004-01-01

    The Plasma and Ion Source Technology Group at the Lawrence Berkeley National Laboratory has been engaging in the development of high yield compact neutron generators for the last ten years. Because neutrons in these generators are formed by using either D-D, T-T or D-T fusion reaction, one can produce either mono-energetic (2.4 MeV or 14 MeV) or white neutrons. All the neutron generators being developed by our group utilize 13.5 MHz RF induction discharge to produce a pure deuterium or a mixture of deuterium-tritium plasma. As a result, ion beams with high current density and almost pure atomic ions can be extracted from the plasma source. The ion beams are accelerated to ∼100 keV and neutrons are produced when the beams impinge on a titanium target. Neutron generators with different configurations and sizes have been designed and tested at LBNL. Their applications include neutron activation analysis, oil-well logging, boron neutron capture therapy, brachytherapy, cargo and luggage screening. A novel small point neutron source has recently been developed for radiography application. The source size can be 2 mm or less, making it possible to examine objects with sharper images. The performance of these neutron generators will be described in this paper

  14. Measurement for skyshine of neutron generated by the K-600 neutron generator

    International Nuclear Information System (INIS)

    Zhen Huazhi; Li Guisheng; Wu Jingmin; Li Jianping

    1988-01-01

    The attenuation low of neutron scattering in atmosphere that generated by K-600 neutron generator at IMP was measured in order to evaluate the effect of the neutron generator to surroundings. The attenuation lenth λ = 396m was obtained and this result is in aggreement with the measured data at some laboratories abroad

  15. Compact neutron generator with nanotube ion source

    Science.gov (United States)

    Chepurnov, A. S.; Ionidi, V. Y.; Ivashchuk, O. O.; Kirsanov, M. A.; Kitsyuk, E. P.; Klenin, A. A.; Kubankin, A. S.; Nazhmudinov, R. M.; Nikulin, I. S.; Oleinik, A. N.; Pavlov, A. A.; Shchagin, A. V.; Zhukova, P. N.

    2018-02-01

    In this letter, we report the observation of fast neutrons generated when a positive acceleration potential is applied to an array of orientated carbon nanotubes, which are used as an ion source. The neutrons with energy of 2.45 MeV are generated as a result of D-D fusion reaction. The dependencies of the neutron yield on the value of the applied potential and residual pressure of deuterium are measured. The proposed approach is planned to be used for the development of compact neutron generators.

  16. Spectra and absorbed dose by photo-neutrons in a solid water mannequin exposed to a Linac of 15 MV

    International Nuclear Information System (INIS)

    Benites R, J.; Vega C, H. R.; Velazquez F, J.

    2012-10-01

    Using Monte Carlo methods was modeled a solid water mannequin; according to the ICRU 44 (1989), Tissue substitutes in radiation dosimetry and measurements, of the International Commission on Radiation Units and Measurements; Report 44. This material Wt 1 is made of H (8.1%), C (67.2%), N (2.4%), O (19.9%), Cl (0.1%), Ca (2.3%) and its density is of 1.02 gr/cm 3 . The mannequin was put instead of the patient, inside the treatment room and the spectra and absorbed dose were determined by photo-neutrons exposed to a Linac of 15 MV. (Author)

  17. Beam intensity increases at the intense pulsed neutron source accelerator

    International Nuclear Information System (INIS)

    Potts, C.; Brumwell, F.; Norem, J.; Rauchas, A.; Stipp, V.; Volk, G.

    1985-01-01

    The Intense Pulsed Neutron Source (IPNS) accelerator system has managed a 40% increase in time average beam current over the last two years. Currents of up to 15.6μA (3.25 x 10 12 protons at 30 Hz) have been successfully accelerated and cleanly extracted. Our high current operation demands low loss beam handling to permit hands-on maintenance. Synchrotron beam handling efficiencies of 90% are routine. A new H - ion source which was installed in March of 1983 offered the opportunity to get above 8 μA but an instability caused unacceptable losses when attempting to operate at 10 μA and above. Simple techniques to control the instabilities were introduced and have worked well. These techniques are discussed below. Other improvements in the regulation of various power supplies have provided greatly improved low energy orbit stability and contributed substantially to the increased beam current

  18. Development of a Portable Fusion Neutron Generator

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Byung-Hoon; In, Sang-Ryul; Jin, Jeong-Tae; Chang, Dae-Sik; Jang, Doh-Yun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Cheol Ho [Hanyang Univ., Seoul (Korea, Republic of)

    2015-05-15

    For this purpose commercial ones, fast neutron yield from 10{sup 7} to 10{sup 11}, are supplied by several companies and research groups around the world. But internally the following limits make it difficult to develop the related application systems by domestic companies and/or research groups. - Limited life time - High price - Frequent trouble Not only to remove these limits but also to find out new internal application fields, it is necessary to develop our own domestic neutron generators. With the related technologies earned during fusion related researches, we did start to develop movable neutron generators from small one to big one, which could cover different fusion neutron yields. In this presentation the design and initial experimental results on the developed small neutron generator with a final target of 10{sup 8} n/s of 14 MeV neutrons, will be summarized.

  19. Estimation of neutron production from accelerator head assembly of 15 MV medical LINAC using FLUKA simulations

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-12-15

    For the production of a clinical 15 MeV photon beam, the design of accelerator head assembly has been optimized using Monte Carlo based FLUKA code. The accelerator head assembly consists of e-{gamma} target, flattening filter, primary collimator and an adjustable rectangular secondary collimator. The accelerators used for radiation therapy generate continuous energy gamma rays called Bremsstrahlung (BR) by impinging high energy electrons on high Z materials. The electron accelerators operating above 10 MeV can result in the production of neutrons, mainly due to photo nuclear reaction ({gamma}, n) induced by high energy photons in the accelerator head materials. These neutrons contaminate the therapeutic beam and give a non-negligible contribution to patient dose. The gamma dose and neutron dose equivalent at the patient plane (SSD = 100 cm) were obtained at different field sizes of 0 Multiplication-Sign 0, 10 Multiplication-Sign 10, 20 Multiplication-Sign 20, 30 Multiplication-Sign 30 and 40 Multiplication-Sign 40 cm{sup 2}, respectively. The maximum neutron dose equivalent is observed near the central axis of 30 Multiplication-Sign 30 cm{sup 2} field size. This is 0.71% of the central axis photon dose rate of 0.34 Gy/min at 1 {mu}A electron beam current.

  20. Status of the intense pulsed neutron source

    International Nuclear Information System (INIS)

    Carpenter, J.M.; Brown, B.S.; Kustom, R.L.; Lander, G.H.; Potts, C.W.; Schulke, A.W.; Wuestefeld, G.

    1985-01-01

    Fortunately in spite of some premature reports of its impending demise, IPNS has passed the fourth anniversary of the first delivery of protons to the targets (May 5, 1981) and is approaching the fourth anniversary of its operation as a scattering facility (August 4, 1981). On June 10, 1984, the RCS delivered its one billionth pulse to the IPNS target - the total number of protons delivered to the targets amounted then to 75 stp cm 3 of H 2 gas. Since startup IPNS has improved steadily in terms of the performance of the Rapid Cycling Synchrotron, the source and its moderators and the scattering instruments, and a substantial and productive user program has evolved. This report summarizes the current status of the Intense Pulsed Neutron Source at Argonne National Laboratory. We include reference to recent accelerator operating experience, neutron facility operating experience, improvements to these systems, design work on the ASPUN high-current facility, booster target design, the new solid methane moderator, characterization of the room temperature moderators, and provide some examples of recent results from several of the spectrometers

  1. Pulsed neutron source very intense, Booster

    International Nuclear Information System (INIS)

    Abbate, J.M.

    1978-09-01

    A compact Accelerator-Booster (fast, pulsed and modulate reactivity research reactor) is a new and appropriate conception to use as a very intense thermal neutrons source. Its definition and feasibility have been already described in several studies showing its relative advantages in comparison with others kinds of facilities. This work, wich is part of one of those studies, contains a general analysis on the meis facility parameters and core and shielding theoretical calculations. The following results were obtained: Selection and test of a calculation system suitable to use in compact fast reactors; Development a method to perform estimations in some safety and shielding problems and obtainment of adequate theoretical predictions on the general performance. Moreover, final results for importent parameters of the feasibility study and predesign (critical mass and volume, lifetime, etc.) and others related to the use of plutonium oxide as fuel are given and then evaluations of different basic functions are showed. (author) [es

  2. New portable neutron generator for well logging

    International Nuclear Information System (INIS)

    Chicanov, A.E.; Gromov, E. V.; Gulko, V. M.; Izmailov, A. V.

    1994-01-01

    The information about the design, investigation and testing of new well neutron generator for the pulse neutron logging (PNL) is given in this paper. The main physical characteristics of new PNL apparatus are: Neutron flux 2.10 sup 8 n/s ; Pulse frequency>=400 Hz; Diameter= 90 mm; Logging velocity >200 m/h; Number of probes = 2; Resource > 300 h. The generator were provided by gas-filled neutron accelerative tube named NTF-2. The perspective of application and optimization shown PNL apparatus are considered. (author)

  3. Advances in 14 MeV neutron activation analysis by means of a new intense neutron source

    International Nuclear Information System (INIS)

    Pepelnik, R.; Fanger, H.-U.; Michaelis, W.; Anders, B.

    1982-01-01

    A new intense 14 MeV neutron generator with cylindrical acceleration structure has been put in operation at the GKSS Research Center Geesthacht. The sealed neutron tube is combined with a fast pneumatic rabbit system with particular capabilities for neutron activation analysis involving short-lived reaction products. The sample transfer time is less than 140 ms. The maximum neutron flux available for activation is 5.2x10 10 n/cm 2 s. Theoretical sensitivity predictions made in a previous study have been verified for some important trace elements. As a first application, samples of freeze-dried suspended matter and fishes of the Elbe river were analyzed. (author)

  4. Characteristics of a Portable Neutron Generator

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Jeong-Tae; Oh, Byung-Hoon; Chang, Dae-Sik; In, Sang-Yeol; Huh, Sung-Ryul; Hong, Kwang-Pyo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Neutron generators can be excellent tools for materials analysis, explosive material detection, nuclear weapon detection, and high quality radiography. D + D : 3He + n (2.5 MeV) D + T : 4He + n (14 MeV) Recent commercial neutron generators, fast neutron yield from 10{sup 7} to 10{sup 11} n/s, are produced by several companies and research groups around the world. But limited life time, high price, and frequent troubles make it difficult to develop related application systems by domestic companies or research groups. To remove such problems, it is necessary to develop our own domestic neutron generators. In this presentation, the design and experimental results on the developed small neutron generator are summarized. Experiments on deuterium beam extraction and fast neutron measurement by injecting deuterium beams on a drive-in target are executed. The stable deuterium beam of the energy higher than 100 keV was achieved by introducing metal cover which reduces the effect of metal-vacuum-insulator triple junction. The neutron flux of 5 n/s is measured by RadEye GN gamma Neutron (Thermo scientific) detector with about 200 mm distance and insertion of 40 mm PE plate between neutron source and the detector. The precise detector calibration is not carried out yet, so more detailed experimental results will be summarized at the presentation.

  5. Characteristics of a Portable Neutron Generator

    International Nuclear Information System (INIS)

    Jin, Jeong-Tae; Oh, Byung-Hoon; Chang, Dae-Sik; In, Sang-Yeol; Huh, Sung-Ryul; Hong, Kwang-Pyo

    2015-01-01

    Neutron generators can be excellent tools for materials analysis, explosive material detection, nuclear weapon detection, and high quality radiography. D + D : 3He + n (2.5 MeV) D + T : 4He + n (14 MeV) Recent commercial neutron generators, fast neutron yield from 10 7 to 10 11 n/s, are produced by several companies and research groups around the world. But limited life time, high price, and frequent troubles make it difficult to develop related application systems by domestic companies or research groups. To remove such problems, it is necessary to develop our own domestic neutron generators. In this presentation, the design and experimental results on the developed small neutron generator are summarized. Experiments on deuterium beam extraction and fast neutron measurement by injecting deuterium beams on a drive-in target are executed. The stable deuterium beam of the energy higher than 100 keV was achieved by introducing metal cover which reduces the effect of metal-vacuum-insulator triple junction. The neutron flux of 5 n/s is measured by RadEye GN gamma Neutron (Thermo scientific) detector with about 200 mm distance and insertion of 40 mm PE plate between neutron source and the detector. The precise detector calibration is not carried out yet, so more detailed experimental results will be summarized at the presentation

  6. Multiple-linac approach for tritium production and other applications

    International Nuclear Information System (INIS)

    Ruggiero, A.G.

    1995-01-01

    This report describes an approach to tritium production based on the use of multiple proton linear accelerators. Features of a single APTT Linac as proposed by the Los Alamos National Laboratory are presented and discussed. An alternative approach to the attainment of the same total proton beam power of 200 MW with several lower-performance superconducting Linacs is proposed and discussed. Although each of these accelerators are considerable extrapolations of present technology, the latter can nevertheless be built at less technical risk when compared to the single high-current APT Linac, particularly concerning the design and the performance of the low-energy front-end. The use of superconducting cavities is also proposed as a way of optimizing the accelerating gradient, the overall length, and the operational costs. The superconducting technology has already been successfully demonstrated in a number of large-size projects and should be seriously considered for the acceleration of intense low-energy beams of protons. Finally, each linear accelerator would represent an ideal source of very intense beams of protons for a variety of applications, such as: weapons and waste actinide transmutation processes, isotopes for medical application, spallation neutron sources, and the generation of intense beams of neutrinos and muons for nuclear and high-energy physics research. The research community at large has obviously an interest in providing expertise for, and in having access to, the demonstration, the construction, the operation, and the exploitation of these top-performance accelerators

  7. Neutron Generators for Spent Fuel Assay

    International Nuclear Information System (INIS)

    Ludewigt, Bernhard A.

    2010-01-01

    The Next Generation Safeguards Initiative (NGSI) of the U.S. DOE has initiated a multi-lab/university collaboration to quantify the plutonium (Pu) mass in, and detect the diversion of pins from, spent nuclear fuel (SNF) assemblies with non-destructive assay (NDA). The 14 NDA techniques being studied include several that require an external neutron source: Delayed Neutrons (DN), Differential Die-Away (DDA), Delayed Gammas (DG), and Lead Slowing-Down Spectroscopy (LSDS). This report provides a survey of currently available neutron sources and their underlying technology that may be suitable for NDA of SNF assemblies. The neutron sources considered here fall into two broad categories. The term 'neutron generator' is commonly used for sealed devices that operate at relatively low acceleration voltages of less than 150 kV. Systems that employ an acceleration structure to produce ion beam energies from hundreds of keV to several MeV, and that are pumped down to vacuum during operation, rather than being sealed units, are usually referred to as 'accelerator-driven neutron sources.' Currently available neutron sources and future options are evaluated within the parameter space of the neutron generator/source requirements as currently understood and summarized in section 2. Applicable neutron source technologies are described in section 3. Commercially available neutron generators and other source options that could be made available in the near future with some further development and customization are discussed in sections 4 and 5, respectively. The pros and cons of the various options and possible ways forward are discussed in section 6. Selection of the best approach must take a number of parameters into account including cost, size, lifetime, and power consumption, as well as neutron flux, neutron energy spectrum, and pulse structure that satisfy the requirements of the NDA instrument to be built.

  8. Neutronics activities for next generation devices

    International Nuclear Information System (INIS)

    Gohar, Y.

    1985-01-01

    Neutronic activities for the next generation devices are the subject of this paper. The main activities include TFCX and FPD blanket/shield studies, neutronic aspects of ETR/INTOR critical issues, and neutronics computational modules for the tokamak system code and tandem mirror reactor system code. Trade-off analyses, optimization studies, design problem investigations and computational models development for reactor parametric studies carried out for these activities are summarized

  9. Intense pulsed neutron source accelerator status

    International Nuclear Information System (INIS)

    Potts, C.W.; Brumwell, F.R.; Stipp, V.F.

    1983-01-01

    The Intense Pulsed Neutron Source (IPNS) facility has been in operation since November 1, 1981. From that date through August 1, 1983, the accelerator system was scheduled for 7191 hours of operation. During this period, 627 million pulses totaling about 1.1 x 10 21 protons were delivered to the spallation target. The accelerator has exceeded goals set in 1981 by averaging 8.65 μA over this two year period. This average beam current, while modest by the standards of proposed machines, makes the IPNS synchrotron (Rapid Cycling Synchrotron [RCS]) the highest intensity proton synchrotron in the world today. Detailed data on accelerator operation are presented. Weekly average currents of 12 μA have been achieved along with peaks of 13.9 μA. A great deal has been learned about the required operating constraints during high beam current operation. It should be possible to increase the average beam current during this next year to 12 μA while observing these restraints. Improvement plans have been formulated to increase the beam current to 16 μA over the next three years

  10. Linear induction accelerators for fusion and neutron production

    International Nuclear Information System (INIS)

    Barletta, W.A.; California Univ., Los Angeles, CA

    1993-08-01

    Linear induction accelerators (LIA) with pulsed power drives can produce high energy, intense beams or electrons, protons, or heavy ions with megawatts of average power. The continuing development of highly reliable LIA components permits the use such accelerators as cost-effective beam sources to drive fusion pellets with heavy ions, to produce intense neutron fluxes using proton beams, and to generate with electrons microwave power to drive magnetic fusion reactors and high gradient, rf-linacs

  11. New generation non-stationary portable neutron generators for biophysical applications of Neutron Activation Analysis.

    Science.gov (United States)

    Marchese, N; Cannuli, A; Caccamo, M T; Pace, C

    2017-01-01

    Neutron sources are increasingly employed in a wide range of research fields. For some specific purposes an alternative to existing large-scale neutron scattering facilities, can be offered by the new generation of portable neutron devices. This review reports an overview for such recently available neutron generators mainly addressed to biophysics applications with specific reference to portable non-stationary neutron generators applied in Neutron Activation Analysis (NAA). The review reports a description of a typical portable neutron generator set-up addressed to biophysics applications. New generation portable neutron devices, for some specific applications, can constitute an alternative to existing large-scale neutron scattering facilities. Deuterium-Deuterium pulsed neutron sources able to generate 2.5MeV neutrons, with a neutron yield of 1.0×10 6 n/s, a pulse rate of 250Hz to 20kHz and a duty factor varying from 5% to 100%, when combined with solid-state photon detectors, show that this kind of compact devices allow rapid and user-friendly elemental analysis. "This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo". Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Pulsed thermal neutron source at the fast neutron generator.

    Science.gov (United States)

    Tracz, Grzegorz; Drozdowicz, Krzysztof; Gabańska, Barbara; Krynicka, Ewa

    2009-06-01

    A small pulsed thermal neutron source has been designed based on results of the MCNP simulations of the thermalization of 14 MeV neutrons in a cluster-moderator which consists of small moderating cells decoupled by an absorber. Optimum dimensions of the single cell and of the whole cluster have been selected, considering the thermal neutron intensity and the short decay time of the thermal neutron flux. The source has been built and the test experiments have been performed. To ensure the response is not due to the choice of target for the experiments, calculations have been done to demonstrate the response is valid regardless of the thermalization properties of the target.

  13. Neutron flux stabilization in the NG-150 neutron generators

    International Nuclear Information System (INIS)

    Kuz'min, L.E.; Makarov, S.A.; Pronman, I.M.

    1986-01-01

    Problem of metal tritium target lifetime increase and neutron flux stabilization in the NG-150 neutron generators is studied. Possibility on neutron flux stabilization using the mass analyzer for low-angle (4 deg and 41 deg) mass separation of a beam in thre components, which fall on a target simultaneously, is confirmed experimentally. Basic generator parameters are: accelerating voltage of 150 kV, total beam current on a target of 1.5 mA, beam current density of 0.3-1.6 mA/cm 2 , beam diameter of 8 mm. The initial neutron flux on the targets of 0.73 mg/cm 2 thick constituted 1.1x10 11 ssup(-1). The neutron flux monitoring was accomplished from recoil proton recording by a plastic scintillator. Flux decrease by more than 5% served as a signel for measuring mass analyzer magnetic field providing beam displacement on a target and restoration of the given flux. The NG-150 generator neutron flux stabilization was attained during 2h

  14. Pulsed neutron source and instruments at neutron facility

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-01

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

  15. Integrating techniques for neutron dosimetry in Linac 18 MV; Integrando tecnicas para dosimetria de neutrones en un Linac de 18 MV

    Energy Technology Data Exchange (ETDEWEB)

    Ceron R, P. V.; Diaz G, J. A. I.; Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, 11500 Mexico D. F. (Mexico); Paredes G, L. C. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2015-10-15

    In this paper thermoluminescent dosimetry, analytical techniques and Monte Carlo calculations were used to estimate the neutron dose equivalent in a radiotherapy room with a linear electron accelerator of 18 MV. The equivalent dose was measured at isocenter to 1.42 m of target and at the entrance of the labyrinth of the room of a Novalis Tx. The neutron detectors were constructed with pairs of thermoluminescent dosimeters TLD 600 ({sup 6}LiF: Mg, Ti) and TLD 700 ({sup 7}LiF: Mg, Ti) which are placed inside a paraffin sphere of 20 cm in diameter. These measurements enabled the calculation of equivalent dose in the gate and the source term, using the relationships contained in the NCRP-151. Through the models carried out with the code MCNPX the absorbed dose distribution with regard to depth in a paraffin phantom are included and the neutron spectrum produced by the head, taking into account the geometry and component materials. The results are in the order of neutron milli sievert by gray of X-rays (mSv/Gy x) which are in the same order as those found in other reports for different accelerators. (Author)

  16. Investigation of Response of Several Neutron Surveymeters by a DT Neutron Generator

    International Nuclear Information System (INIS)

    Kim, Sang In; Jang, In Su; Kim, Jang Lyul; Lee, Jung IL; Kim, Bong Hwan

    2012-01-01

    Several neutron measuring devices were tested under the neutron fields characterized with two distinct kinds of thermal and fast neutron spectrum. These neutron fields were constructed by the mixing of both thermal neutron fields and fast neutron fields. The thermal neutron field was constructed using by a graphite pile with eight AmBe neutron sources. The fast neutron field of 14 MeV was made by a DT neutron generator. In order to change the fraction of fast neutron fluence rate in each neutron fields, a neutron generator was placed in the thermal neutron field at 50 cm and 150 cm from the reference position. The polyethylene neutron collimator was used to make moderated 14 MeV neutron field. These neutron spectra were measured by using a Bonner sphere system with an LiI scintillator, and dosimetric quantities delivered to neutron surveymeters were determined from these measurement results.

  17. Neutron generator tube ion source control

    International Nuclear Information System (INIS)

    Bridges, J.R.

    1982-01-01

    A system is claimed for controlling the output of a neutron generator tube of the deuterium-tritium accelerator type and having an ion source to produce sharply defined pulses of neutrons for well logging use. It comprises: means for inputting a relatively low voltage input control pulse having a leading edge and a trailing edge; means, responsive to the input control pulse, for producing a relatively high voltage ion source voltage pulse after receipt of the input pulse; and means, responsive to the input control pulse, for quenching, after receipt of the input pulse, the ion source control pulse, thereby providing a sharply time defined neutron output from the generator tube

  18. Transport and energy selection of laser generated protons for postacceleration with a compact linac

    Science.gov (United States)

    Sinigardi, Stefano; Turchetti, Giorgio; Londrillo, Pasquale; Rossi, Francesco; Giove, Dario; De Martinis, Carlo; Sumini, Marco

    2013-03-01

    Laser accelerated proton beams have a considerable potential for various applications including oncological therapy. However, the most consolidated target normal sheath acceleration regime based on irradiation of solid targets provides an exponential energy spectrum with a significant divergence. The low count number at the cutoff energy seriously limits at present its possible use. One realistic scenario for the near future is offered by hybrid schemes. The use of transport lines for collimation and energy selection has been considered. We present here a scheme based on a high field pulsed solenoid and collimators which allows one to select a beam suitable for injection at 30 MeV into a compact linac in order to double its energy while preserving a significant intensity. The results are based on a fully 3D simulation starting from laser acceleration.

  19. Transport and energy selection of laser generated protons for postacceleration with a compact linac

    Directory of Open Access Journals (Sweden)

    Stefano Sinigardi

    2013-03-01

    Full Text Available Laser accelerated proton beams have a considerable potential for various applications including oncological therapy. However, the most consolidated target normal sheath acceleration regime based on irradiation of solid targets provides an exponential energy spectrum with a significant divergence. The low count number at the cutoff energy seriously limits at present its possible use. One realistic scenario for the near future is offered by hybrid schemes. The use of transport lines for collimation and energy selection has been considered. We present here a scheme based on a high field pulsed solenoid and collimators which allows one to select a beam suitable for injection at 30 MeV into a compact linac in order to double its energy while preserving a significant intensity. The results are based on a fully 3D simulation starting from laser acceleration.

  20. Smooth transverse and longitudinal focusing in high-intensity ion linacs

    International Nuclear Information System (INIS)

    Billen, J.H.; Takeda, Harunori; Young, L.M.

    1996-01-01

    We examine ion linac designs that start with a high energy radio- frequency quadrupole (RFQ) followed by either a drift-tube linac (DTL) or a coupled-cavity drift-tube linac (CCDTL). For high energies a conventional CCL follows the CCDTL. High RFQ output energy allows tailoring the transverse and longitudinal focusing strengths to match into the following structure. When the RFQ beam enters a higher frequency structure, the DTL or CCDTL starts with a low accelerating gradient and large negative synchronous phase. The gradient and phase both ramp up gradually to higher values. Other changes later in the machine are also gradual. Beam dynamics simulations show that these linacs require no separate matching sections. Applications include a cw 100 mA H + beam from a 350-MHz, 6.7 MeV RFQ injecting a 700 MHz CCDTL and CCL; a 7% duty 28 mA H - beam from a 402.5 MHz RFQ and DTL injecting 805 MHz structures; a cw 135 mA D + beam produced by a 175 MHz, 8 MeV RFQ and DTL; and a 2.4% duty, 80 mA H + beam using a 433 MHz 10 MeV RFQ and a 1300 MHz CCDTL. The machines take advantage of the considerable flexibility of the CCDTL. Designs can use a variety of different transverse focusing lattices. Use of two coupling cavity orientations permits a constant period even when the number of drift tubes per cavity changes along the linac

  1. Calibration of PADC-based neutron area dosemeters in the neutron field produced in the treatment room of a medical LINAC

    International Nuclear Information System (INIS)

    Bedogni, R.; Domingo, C.; Esposito, A.; Gentile, A.; García-Fusté, M.J.; San-Pedro, M. de; Tana, L.; D’Errico, F.; Ciolini, R.; Di Fulvio, A.

    2013-01-01

    PADC-based nuclear track detectors have been widely used as convenient ambient dosemeters in many working places. However, due to the large energy dependence of their response in terms of ambient dose equivalent (H ∗ (10)) and to the diversity of workplace fields in terms of energy distribution, the appropriate calibration of these dosemeters is a delicate task. These are among the reasons why ISO has introduced the 12789 Series of Standards, where the simulated workplace neutron fields are introduced and their use to calibrate neutron dosemeters is recommended. This approach was applied in the present work to the UAB PADC-based nuclear track detectors. As a suitable workplace, the treatment room of a 15 MV Varian CLINAC DHX medical accelerator, located in the Ospedale S. Chiara (Pisa), was chosen. Here the neutron spectra in two points of tests (1.5 m and 2 m from the isocenter) were determined with the INFN-LNF Bonner Sphere Spectrometer equipped with Dysprosium activation foils (Dy-BSS), and the values of H ∗ (10) were derived on this basis. The PADC dosemeters were exposed in these points. Their workplace specific H*(10) responses were determined and compared with those previously obtained in different simulated workplace or reference (ISO 8529) neutron fields. - Highlights: ► The neutron field of a medical LINAC was used to calibrate PADC neutron dosemeters. ► The neutron spectra were derived with a Dy-foil based Bonner Sphere Spectrometer. ► Workplace specific calibration factor were derived for the PADC dosemeters. ► These factors were compared with those obtained in reference neutron fields

  2. Thermal and epithermal neutron fluence rate gradient measurements by PADC detectors in LINAC radiotherapy treatments-field

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, M. T., E-mail: mariate9590@gmail.com; Barros, H.; Pino, F.; Sajo-Bohus, L. [Universidad Simón Bolívar, Nuclear Physics Laboratory, Sartenejas, Caracas (Venezuela, Bolivarian Republic of); Dávila, J. [Física Médica C. A. and Universidad Central de Venezuela, Caracas (Venezuela, Bolivarian Republic of)

    2015-07-23

    LINAC VARIAN 2100 is where energetic electrons produce Bremsstrahlung radiation, with energies above the nucleon binding energy (E≈5.5MeV). This radiation induce (γ,n) and (e,e’n) reactions mainly in the natural tungsten target material (its total photoneutron cross section is about 4000 mb in a energy range from 9-17 MeV). These reactions may occur also in other components of the system (e.g. multi leaf collimator). During radiation treatment the human body may receive an additional dose inside and outside the treated volume produced by the mentioned nuclear reactions. We measured the neutron density at the treatment table using nuclear track detectors (PADC-NTD). These covered by a boron-converter are employed, including a cadmium filter, to determine the ratio between two groups of neutron energy, i.e. thermal and epithermal. The PADC-NTD detectors were exposed to the radiation field at the iso-center during regular operation of the accelerator. Neutron are determined indirectly by the converting reaction {sup 10}B(n,α){sup 7}Li the emerging charged particle leave their kinetic energy in the PADC forming a latent nuclear track, enlarged by chemical etching (6N, NaOH, 70°C). Track density provides information on the neutron density through calibration coefficient (∼1.6 10{sup 4} neutrons /track) obtained by a californium source. We report the estimation of the thermal and epithermal neutron field and its gradient for photoneutrons produced in radiotherapy treatments with 18 MV linear accelerators. It was obsered that photoneutron production have higher rate at the iso-center.

  3. High intensity TOF spectrometer for cold neutrons

    International Nuclear Information System (INIS)

    Maayouf, R.M.; Abd El-Kawy, A.; Habib, N.; Adib, M.; Hamouda, I.

    1984-01-01

    This work presents a neutron time-of-flight (TOF) spectrometer developed specially for total neutron cross-section measurements at neutron energies below 5 MeV and sample's temperature varying from the liquid nitrogen one and up to 500 0 K. The spectrometer is equipped by remote control unit, designed especially, in order to move the sample in and out of the beam during the experimental measurements. The spectrometer has proved to be useful for transmission measurements at neutron energies below 5 MeV. It has a reasonable energy resolution (4.4%) and high effect to background ratio (11.1) at 5 MeV

  4. Intense neutron sources for cancer treatment

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Significant progress has been made in the development of small, solid-target, pulsed neutron sources for nuclear weapons applications. The feasibility of using this type of neutron source for cancer treatment is discussed. Plans for fabrication and testing of such a source is briefly described

  5. 10 CFR 39.55 - Tritium neutron generator target sources.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target....77. (b) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg...

  6. Measurements of neutron intensity from liquid deuterium moderator of the cold neutron source of KUR

    International Nuclear Information System (INIS)

    Kawai, Takeshi; Ebisawa, Toru; Akiyoshi, Tsunekazu; Tasaki, Seiji

    1990-01-01

    The neutron spectra from the liquid deuterium moderator of the cold neutron source of KUR were measured by the time of flight (TOF) method similar to the previous measurements for the liquid hydrogen moderator. The cold neutron gain factor is found to be about 20 ∼ 28 times for the wavelength longer than 6 A. Cold neutron intensities from the liquid deuterium moderator and from the liquid hydrogen moderator are compared and discussed. (author)

  7. Commissioning the neutron production of a Linac: Development of a simple tool for second cancer risk estimation

    International Nuclear Information System (INIS)

    Romero-Expósito, M.; Sánchez-Nieto, B.; Terrón, J. A.; Lopes, M. C.; Ferreira, B. C.; Grishchuk, D.; Sandín, C.; Moral-Sánchez, S.; Melchor, M.; Domingo, C.

    2015-01-01

    Purpose: Knowing the contribution of neutron to collateral effects in treatments is both a complex and a mandatory task. This work aims to present an operative procedure for neutron estimates in any facility using a neutron digital detector. Methods: The authors’ previous work established a linear relationship between the total second cancer risk due to neutrons (TR n ) and the number of MU of the treatment. Given that the digital detector also presents linearity with MU, its response can be used to determine the TR n per unit MU, denoted as m, normally associated to a generic Linac model and radiotherapy facility. Thus, from the number of MU of each patient treatment, the associated risk can be estimated. The feasibility of the procedure was tested by applying it in eight facilities; patients were evaluated as well. Results: From the reading of the detector under selected irradiation conditions, m values were obtained for different machines, ranging from 0.25 × 10 −4 % per MU for an Elekta Axesse at 10 MV to 6.5 × 10 −4 % per MU for a Varian Clinac at 18 MV. Using these values, TR n of patients was estimated in each facility and compared to that from the individual evaluation. Differences were within the range of uncertainty of the authors’ methodology of equivalent dose and risk estimations. Conclusions: The procedure presented here allows an easy estimation of the second cancer risk due to neutrons for any patient, given the number of MU of the treatment. It will enable the consideration of this information when selecting the optimal treatment for a patient by its implementation in the treatment planning system

  8. Commissioning the neutron production of a Linac: Development of a simple tool for second cancer risk estimation

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Expósito, M., E-mail: mariateresa.romero@uab.cat [Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009, Spain and Departament de Física, Universitat Autònoma de Barcelona, Bellaterra 08193 (Spain); Sánchez-Nieto, B. [Instituto de Física, Pontificia Universidad Católica de Chile, Santiago 4880 (Chile); Terrón, J. A. [Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41009 (Spain); Lopes, M. C. [Serviço de Física Médica, Instituto Português de Oncologia, Coimbra 3000-075 (Portugal); Ferreira, B. C. [i3N, Department of Physics, University of Aveiro, Aveiro 3810-193 (Portugal); Grishchuk, D. [Radiotherapy Service, Russian Research Center for Radiology and Surgical Technology, Saint Petersburg 197758 (Russian Federation); Sandín, C. [Elekta, Ltd., Crawley RH10 9RR (United Kingdom); Moral-Sánchez, S. [Servicio de Radiofísica, Instituto Onkologikoa, San Sebastián 20014 (Spain); Melchor, M. [Servicio de Radiofísica, Hospital Universitario de la Ribera, Alzira 46600, Valencia (Spain); Domingo, C. [Departament de Física, Universitat Autònoma de Barcelona, Bellaterra 08193 (Spain); and others

    2015-01-15

    Purpose: Knowing the contribution of neutron to collateral effects in treatments is both a complex and a mandatory task. This work aims to present an operative procedure for neutron estimates in any facility using a neutron digital detector. Methods: The authors’ previous work established a linear relationship between the total second cancer risk due to neutrons (TR{sup n}) and the number of MU of the treatment. Given that the digital detector also presents linearity with MU, its response can be used to determine the TR{sup n} per unit MU, denoted as m, normally associated to a generic Linac model and radiotherapy facility. Thus, from the number of MU of each patient treatment, the associated risk can be estimated. The feasibility of the procedure was tested by applying it in eight facilities; patients were evaluated as well. Results: From the reading of the detector under selected irradiation conditions, m values were obtained for different machines, ranging from 0.25 × 10{sup −4}% per MU for an Elekta Axesse at 10 MV to 6.5 × 10{sup −4}% per MU for a Varian Clinac at 18 MV. Using these values, TR{sup n} of patients was estimated in each facility and compared to that from the individual evaluation. Differences were within the range of uncertainty of the authors’ methodology of equivalent dose and risk estimations. Conclusions: The procedure presented here allows an easy estimation of the second cancer risk due to neutrons for any patient, given the number of MU of the treatment. It will enable the consideration of this information when selecting the optimal treatment for a patient by its implementation in the treatment planning system.

  9. Neutron generator instrumentation at the Department 2350 Neutron Generator Test Facility

    International Nuclear Information System (INIS)

    Bryant, T.C.; Mowrer, G.R.

    1979-06-01

    The computer and waveform digitizing capability at the test facility has allowed several changes in the techniques used to test neutron generators. These changes include methods used to calibrate the instrumentation and changes in the operation of the test facility. These changes have increased the efficiency of the test facility as well as increasing both timing and amplitude accuracy of neutron generator waveforms

  10. 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)

  11. Conceptual design for an accelerator system for a very high-intensity pulsed neutron source using a linear-induction accelerator

    International Nuclear Information System (INIS)

    Foss, M.H.

    1981-01-01

    Several accelerator-based intense neutron sources have been constructed or designed by various laboratories around the world. All of these facilities have a common scheme of a linac and synchrotron or accumulator ring, and the system produces the proton energy of 500 to 1000 MeV. The average beam currents range from a few mA to a few hundred mA. The protons are then used to generate high-flux neutrons by spallation out of heavy-metal targets. In a synchrotron system, the protons are already bunched, and thus the pulse rate of the neutron beam is that of the repetition rate of the synchrotron. For an accumulator system, the pulse rate is determined by the extraction repetition rate of the accumulator. We have conceptually designed a new system that uses a linear-induction accelerator which can be operated for an average beam current up to a few mA with a repetition rate up to 100 Hz. The details of the design will be given

  12. A neutron survey of a 25 MV x-ray clinical linac treatment room

    International Nuclear Information System (INIS)

    Price, Kenneth W.; Holeman, George R.; Nath, Ravinder

    1978-01-01

    Neutron production in high energy x-ray radiotherapy machines results in unnecessary dose to patients and has been of recent interest to private and Federal agencies. An activation technique has been used to measure fast and thermal neutron fluxes in the high energy x-ray beam, and at radial distances of 1 and 2 meters from the beam axis of the 25 MV Sagittaire Linear Accelerator located at the Yale-New Haven Hospital's Cancer Therapy Center. Phosphorous pentoxide activation detectors were used to monitor the thermal flux and the fast neutron flux above 0.7 MeV neutron energy. Unlike other techniques for measuring neutrons, this detector has been shown to be insensitive to high energy photon interference at the photon dose rates present in the beam. Neutron spectra at various distances from the accelerator target were computed for the treatment room geometry using the Morse Monte Carlo Code (R.C. McCall, SLAC, Personal Communication). Normalization of these spectra provided the means by which the activation products measured in the phosphorous were converted to fast neutron fluxes. Dose equivalent conversion factors were applied to each energy of the calculated neutron spectra and integrated, resulting in fast neutron flux to dose equivalent conversion factors at various locations in the treatment room. Fast neutron dose equivalent was found to maximize in the photon beam, (0.005 - .007 neutron Rem/photon Rad) and decrease with distance thereafter. Thermal neutron dose equivalent was found to be essentially constant through- out the treatment room (∼ 3.35x10 -5 neutron Rem/ photon Rad). (author)

  13. Production of 14 MeV neutrons from D-D neutron generators

    International Nuclear Information System (INIS)

    Cecil, F.E.; Nieschmidt, E.B.

    1986-01-01

    The production of 14 MeV neutrons from a D-D neutron generator resulting from tritium buildup from the d(d,p)t reaction in the target is discussed. The effect of the 14 MeV neutrons on fast neutron activation analysis with D-D neutron generators is evaluated. (orig.)

  14. Fast neutron activation analysis by means of low voltage neutron generator

    Directory of Open Access Journals (Sweden)

    M.E. Medhat

    Full Text Available A description of D-T neutron generator (NG is presented. This machine can be used for fast neutron activation analysis applied to determine some selected elements, especially light elements, in different materials. Procedure of neutron flux determination and efficiency calculation is described. Examples of testing some Egyptian natural cosmetics are given. Keywords: Neutron generator, Fast neutron activation analysis, Elemental analysis

  15. Calibration and evaluation of neutron survey meters used at linac facility

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, A.P. [Instituto de Radioprotecao e Dosimetria - IRD, Av. Salvador Allende s/n, Recreio dos Bandeirantes, CEP 22780-160 Rio de Janeiro (Brazil); Pereira, W.W., E-mail: walsan@ird.gov.b [Instituto de Radioprotecao e Dosimetria - IRD, Av. Salvador Allende s/n, Recreio dos Bandeirantes, CEP 22780-160 Rio de Janeiro (Brazil); Fonseca, E.S. da; Patrao, K.C.S. [Instituto de Radioprotecao e Dosimetria - IRD, Av. Salvador Allende s/n, Recreio dos Bandeirantes, CEP 22780-160 Rio de Janeiro (Brazil); Batista, D.V.S. [Instituto Nacional do Cancer - INCa, Praca Cruz Vermelha, 23 - centro, CEP 20230-130 Rio de Janeiro (Brazil)

    2010-12-15

    Calibrated survey meters from the Neutron Laboratory of the Instituto de Radioprotecao e Dosimetria (IRD) were used to determine the ambient dose-equivalent rate in a 15 MV linear accelerator treatment room at the Instituto Nacional do Cancer (INCa). Three different models of neutron survey meters were calibrated using four neutron radionuclide neutron sources: {sup 241}AmBe({alpha},n), {sup 252}Cf(f,n), heavy-water moderated {sup 252}Cf(f,n), and {sup 238}PuBe({alpha},n). All neutron sources were standardized in a Manganese Sulphate Bath (MSB) absolute primary system. The response of each of these instruments was compared with reference values of ambient dose-equivalent rate. The results demonstrate the complexity of making measurements in the mixed neutron/photon field produced in electron linear accelerator radiotherapy treatment rooms.

  16. Engineering design of a neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Daniel M.; Campos, Tarcísio P.R. de, E-mail: dmcoelho.eng@gmail.com, E-mail: tprcampos@pq.cnpq.br [Universidade Federal de Minas Gerais (NRI/UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear. Nucleo de Radiações Ionizantes

    2017-07-01

    This paper presents an engineering design of a neutron generator (NG). In order to analyze and choose the materials and the appropriate geometry, previous studies of NRI Group (Nucleus for Ionizing Radiation at UFMG - NRI/UFMG) were considered and a model was developed for the simulation of these systems. The efficiency of a neutron generator is measured by the neutron flux. Among the modeling and simulation methods, was employed open software sources for the transmuting cell, aiming to evaluate resonant cavity and for complementary physical analysis. In addition, the titanium target was compared designed based in other studies of NRI Group. Deuterium plasma with a density close to 10{sup 10} particles/cm³, was proposed with a frequency of 0.898 GHz and an approximate wavelength of 110 μm, using a radio frequency antenna up to 2.45 GHz. This compact system includes a hydrogen-isotopes fusor, moderator, reflector and shield. Neutron reflection minimized the neutron escape, increasing the final flux. A insulation material is required to enclose the device. As a conclusion, the investigated nuclear and electromagnetic features of NG have demonstrated that such generator shall have a notable potential for radioisotope generation applied to medical diagnosis. The designs presented will be used to build a 3D model in the NRI laboratory and then a prototype with the selected materials. (author)

  17. Digitizing and analysis of neutron generator waveforms

    International Nuclear Information System (INIS)

    Bryant, T.C.

    1977-11-01

    All neutron generator waveforms from units tested at the SLA neutron generator test site are digitized and the digitized data stored in the CDC 6600 tape library for display and analysis using the CDC 6600 computer. The digitizing equipment consists mainly of seven Biomation Model 8100 transient recorders, Digital Equipment Corporation PDP 11/20 computer, RK05 disk, seven-track magnetic tape transport, and appropriate DEC and SLA controllers and interfaces. The PDP 11/20 computer is programmed in BASIC with assembly language drivers. In addition to digitizing waveforms, this equipment is used for other functions such as the automated testing of multiple-operation electronic neutron generators. Although other types of analysis have been done, the largest use of the digitized data has been for various types of graphical displays using the CDC 6600 and either the SD4020 or DX4460 plotters

  18. Plasma driven neutron/gamma generator

    Science.gov (United States)

    Leung, Ka-Ngo; Antolak, Arlyn

    2015-03-03

    An apparatus for the generation of neutron/gamma rays is described including a chamber which defines an ion source, said apparatus including an RF antenna positioned outside of or within the chamber. Positioned within the chamber is a target material. One or more sets of confining magnets are also provided to create a cross B magnetic field directly above the target. To generate neutrons/gamma rays, the appropriate source gas is first introduced into the chamber, the RF antenna energized and a plasma formed. A series of high voltage pulses are then applied to the target. A plasma sheath, which serves as an accelerating gap, is formed upon application of the high voltage pulse to the target. Depending upon the selected combination of source gas and target material, either neutrons or gamma rays are generated, which may be used for cargo inspection, and the like.

  19. Measurement of intense coherent synchrotron radiation at frequencies around 0.1 THz using the compact S-band linac

    International Nuclear Information System (INIS)

    Sei, Norihiro; Kuroda, Ryunosuke; Yasumoto, Masato; Toyokawa, Hiroyuki; Ogawa, Hiroshi; Koike, Masaki; Yamada, Kawakatsu

    2008-01-01

    We measured intense radiation from an electron bunch in a millimeter wave region using the compact S-band linac. The dependence of the radiation on the electron-bunch charge was measured with an rf detector system at frequencies around 0.1 THz and was confirmed to be a coherent synchrotron radiation (CSR). The total power of the horizontally and vertically polarized CSRs, which were extracted through the Z-cut quartz window within 1 ns, was calculated to be about 88 and 30 nJ/pulse, excluding the absorption by the window. The two-dimensional distribution of the vertically polarized CSR was measured at a distance of about 0.7 m from the radiation point. The CSR distribution was comparatively uniform in the horizontal plane. Intense CSR, which was reflected in the vacuum chamber, was extracted with a delay of about 6 ns. This suggests that measurement of temporal structure is needed for CSR applications

  20. Neutron generator (HIRRAC) and dosimetry study.

    Science.gov (United States)

    Endo, S; Hoshi, M; Takada, J; Tauchi, H; Matsuura, S; Takeoka, S; Kitagawa, K; Suga, S; Komatsu, K

    1999-12-01

    Dosimetry studies have been made for neutrons from a neutron generator at Hiroshima University (HIRRAC) which is designed for radiobiological research. Neutrons in an energy range from 0.07 to 2.7 MeV are available for biological irradiations. The produced neutron energies were measured and evaluated by a 3He-gas proportional counter. Energy spread was made certain to be small enough for radiobiological studies. Dose evaluations were performed by two different methods, namely use of tissue equivalent paired ionization chambers and activation of method with indium foils. Moreover, energy deposition spectra in small targets of tissue equivalent materials, so-called lineal energy spectrum, were also measured and are discussed. Specifications for biological irradiation are presented in terms of monoenergetic beam conditions, dose rates and deposited energy spectra.

  1. Neutron generator based on adiabatic trap

    International Nuclear Information System (INIS)

    Golovin, I.N.; Zhil'tsov, V.A.; Panov, D.A.; Skovoroda, A.A.; Shatalov, G.E.; Shcherbakov, A.G.

    1988-01-01

    A possibility of 14 MeV neutron generator (NG) production on the basis of axial-symmetric adiabatic trap with MHD cusped armature for the testing of materials and elements of the DT reactor first wall and blanket structure is discussed. General requirements to NG are formulated. It is shown that the NG variant discussed meets the requirements formulated. Approximate calculation of the NG parameters has shown that total energy consumption by the generator does not exceed 220 MW at neutron flux specific capacity of 2.5 MW/m 2 and radiation test area of 5-6 m 2

  2. Neutron dosimetry at the intense neutron source (INS)

    International Nuclear Information System (INIS)

    Dierckx, R.

    1977-01-01

    The neutron monitoring consists of two parts: the spectral characterization and the fluence determination. The experimental measurements are combined with theoretical calculations. The following methods are proposed for determining the spectra: a telescope (np) spectrometer, a telescope 6 Li(nα)T spectrometer, spectrometers needing unfolding, time-of-flight technique, and multiple foil technique

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-11-15

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

  4. Conformal intensity-modulated radiotherapy (IMRT) delivered by robotic linac-conformality versus efficiency of dose delivery

    International Nuclear Information System (INIS)

    Webb, Steve

    2000-01-01

    Intensity-modulated radiotherapy (IMRT) may be delivered with a high-energy-photon linac mounted on a robotic gantry and executing a complex trajectory. In a previous paper an inverse-planning technique was developed for such an application. Here the work is extended to demonstrate the dependence of conformality on the size of the elemental pencil beam, on the complexity of the trajectory and on the sampling of azimuth and elevation of the collimated source. The improved conformality of complex trajectories is demonstrated and benchmarked relative to simpler trajectories, more representative of existing non-robotic IMRT techniques. Specifically, by choosing a very fine pencil beam, exquisitely conformal dose distributions have been obtained. Important sampling considerations have been determined. Expressions have been derived for the dosimetry and monitor-unit efficiency of robotic IMRT. Equivalent trajectories were computed for executing the complex robotic trajectories instead by using a conventional linac. The work benchmarks an ideal in IMRT against which more practical and more common techniques may be measured. (author)

  5. Measurement of the neutron spectrum in a room with an accelerator Varian 2300C/D Linac using the Bonner multisphere spectrometer; Medicao do espectro de neutrons em uma sala com um acelerador Varian 2300C/D Linav usando o espectrometro de multiesferas de Bonner

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcante, D.B.S., E-mail: cavalcante@ird.gov.b [Universidade Federal do Rio de Janeiro (IF/UFRJ), RJ (Brazil). Inst. de Fisica; Fonseca, E.S. da, E-mail: evaldo@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Lemos Junior, R.M. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil); Batista, D.V.S. [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil)

    2009-07-01

    The generated neutron field varies considerably and depends on the beam energy, on the shielding of the accelerator, on the filters for beam homogeneity, and also on the mobile collimators and geometry of irradiation. The estimation of the component relative to the photoneutrons has practical interest for evaluation of the radiological risks for the workers and for the patient as well. Due to the high frequency magnetic field, and to the photon abundance resulting of the escape and scattering at treatment room, those measurements present some difficulties. Measurements of the neutron fields can be made with a Bonner spectrometer. Those system was calibrated with referred neutron standard sources and used for make measurements on a spot of the room where a Variant 2300C/D Linac is installed. The unfolding process used the BUNKI computer code for determination of the neutron spectra at the measurement spot

  6. Secondary electron ion source neutron generator

    Science.gov (United States)

    Brainard, John P.; McCollister, Daryl R.

    1998-01-01

    A neutron generator employing an electron emitter, an ion source bombarded by the electrons from the electron emitter, a plasma containment zone, and a target situated between the plasma containment zone and the electron emitter. The target contains occluded deuterium, tritium, or a mixture thereof

  7. Linac pre-injector

    CERN Multimedia

    CERN PhotoLab

    1965-01-01

    New accelerating column of the linac pre-injector, supporting frame and pumping system. This new system uses two mercury diffusion pumps (in the centre) and forms part of the modifications intended to increase the intensity of the linac. View taken during assembly in the workshop.

  8. Utilization of a pulsed D-T neutron generator

    International Nuclear Information System (INIS)

    Vilaithong, T.; Singkarat, S.; Tippawan, U.

    2000-01-01

    In the past two decades the IAEA has supported the establishment of neutron laboratories in many developing countries by providing small D-T neutron generators. The neutron generator is basically a low energy (100-400 keV) ion accelerator capable of producing a continuous beam of deuterons with a current in the range between 1-2.5 mA. These neutron generators are primarily intended to be used for fast neutron activation analysis. This paper describes the utilization of a 14 MeV neutron generator in continuous and pulsed beam modes in applied neutron physics program at Chiang Mai University. (author)

  9. NAA using the photoneutrons of a Linac as a neutron source

    International Nuclear Information System (INIS)

    Rivera P, E.; De Leon M, H. A.; Hernandez D, V. M.; Vega C, H. R.; Soto B, T.; Gallego, E.; Lorente, A.

    2012-10-01

    Linear accelerators working above 8 MV produce photoneutrons that represent a radiological risk in the patient and hospital staff. In this work a moderator has been designed in the aim to use the photoneutron field to perform neutron activation analysis (NAA) of small samples. The moderator has been designed using Monte Carlo methods, here the photoneutron spectrum is modified by the moderator having the maximum thermal neutron flux in the moderator cavity where the sample to be analyzed is located. (Author)

  10. Characterization of Deuteron-Deuteron Neutron Generators

    Science.gov (United States)

    Waltz, Cory Scott

    A facility based on a next-generation, high-flux D-D neutron generator (HFNG) was commissioned at the University of California Berkeley. The characterization of the HFNG is presented in the following study. The current generator design produces near mono-energetic 2.45 MeV neutrons at outputs of 108 n/s. Calculations provided show that future conditioning at higher currents and voltages will allow for a production rate over 1010 n/s. Characteristics that effect the operational stability include the suppression of the target-emitted back streaming electrons, target sputtering and cooling, and ion beam optics. Suppression of secondary electrons resulting from the deuterium beam striking the target was achieved via the implementation of an electrostatic shroud with a voltage offset of greater than -400 V relative to the target. Ion beam optics analysis resulted in the creation of a defocussing extraction nozzle, allowing for cooler target temperatures and a more compact design. To calculate the target temperatures, a finite difference method (FDM) solver incorporating the additional heat removal effects of subcooled boiling was developed. Validation of the energy balance results from the finite difference method calculations showed the iterative solver converged to heat removal results within about 3% of the expected value. Testing of the extraction nozzle at 1.43 mA and 100 kV determined that overheating of the target did not occur as the measured neutron flux of the generator was near predicted values. Many factors, including the target stopping power, deuterium atomic species, and target loading ratio, affect the flux distribution of the HFNG neutron generator. A detailed analysis to understand these factors effects is presented. Comparison of the calculated flux of the neutron generator using deuteron depth implantation data, neutron flux distribution data, and deuterium atomic species data matched the experimentally calculated flux determined from indium foil

  11. Electromagnetic design of a β=0.4 superconducting spoke resonator for a high intensity proton linac

    International Nuclear Information System (INIS)

    Pathak, Abhishek; Krishnagopal, Srinivas

    2015-01-01

    Here we present electromagnetic design simulations of a superconducting single-spoke resonator with a geometrical beta of 0.4 and operating at 325 MHz for a high intensity proton linac (HIPL). The spoke equatorial and base parameters were optimized to minimize the peak electric and peak magnetic fields and maximize the shunt impedance, while keeping the same resonant frequency. Variation of the surface magnetic fields was investigated as a function of the spoke base shape, and it was found that an elliptical profile is preferred over a circular or racecourse profile with E peak /E acc =4.71, E peak /E acc =4.33 (mT/(MV/m)) and R/Q=272 Ω. (author)

  12. Development of bunch shape monitor for high-intensity beam on the China ADS proton LINAC Injector II

    Science.gov (United States)

    Zhu, Guangyu; Wu, Junxia; Du, Ze; Zhang, Yong; Xue, Zongheng; Xie, Hongming; Wei, Yuan; Jing, Long; Jia, Huan

    2018-05-01

    The development, performance, and testing of the longitudinal bunch shape monitor, namely, the Fast Faraday Cup (FFC), are presented in this paper. The FFC is an invasive instrument controlled by a stepper motor, and its principle of operation is based on a strip line structure. The longitudinal bunch shape was determined by sampling a small part of the beam hitting the strip line through a 1-mm hole. The rise time of the detector reached 24 ps. To accommodate experiments that utilize high-intensity beams, the materials of the bunch shape monitor were chosen to sustain high temperatures. Water cooling was also integrated in the detector system to enhance heat transfer and prevent thermal damage. We also present an analysis of the heating caused by the beam. The bunch shape monitor has been installed and commissioned at the China ADS proton LINAC Injector II.

  13. The use the a high intensity neutrino beam from the ESS proton linac for measurement of neutrino CP violation and mass hierarchy

    CERN Document Server

    Baussan, E.; Ekelof, T.; Martinez, E.Fernandez; Ohman, H.; Vassilopoulos, N.

    2012-01-01

    It is proposed to complement the ESS proton linac with equipment that would enable the production, concurrently with the production of the planned ESS beam used for neutron production, of a 5 MW beam of 10$^{23}$ 2.5 GeV protons per year in microsecond short pulses to produce a neutrino Super Beam, and to install a megaton underground water Cherenkov detector in a mine to detect $\

  14. A neutron beam facility at Spiral-2

    Energy Technology Data Exchange (ETDEWEB)

    Ledoux, X.; Bauge, E.; Belier, G.; Ethvignot, T.; Taieb, J.; Varignon, C. [CEA Bruyeres-le-Chatel, DIF, 91 (France); Andriamonje, S.; Dore, D.; Dupont, E.; Gunsing, F.; Ridikas, D.; Takibayev, A. [CEA Saclay, DSM/IRFU/SPhN, 91 - Gif-sur-Yvette (France); Blideanu, V. [CEA Saclay, DSM/IRFU/Senac, 91 - Gif-sur-Yvette (France); Aiche, M.; Barreau, G.; Czajkowski, S.; Jurado, B. [Centre d' Etudes Nucleaires de Bordeaux Gradignan, 33 (France); Ban, G.; Lecolley, F.R.; Lecolley, J.F.; Lecouey, J.L.; Marie, N.; Steckmeyer, J.C. [LPC, 14 - Caen (France); Dessagne, P.; Kerveno, M.; Rudolf, G. [IPHC, 57 - Strasbourg (France); Bem, P.; Mrazek, J.; Novak, J. [NPI, Rez (Czech Republic); Blomgren, J.; Pomp, S. [Uppsala Univ., Dept. of Physics and Astronomy (Sweden); Fischer, U.; Herber, S.; Simakov, S.P. [FZK, Karlsruhe (Germany); Jacquot, B.; Rejmund, F. [GANIL, 14 - Caen (France); Avrigeanu, M.; Avrigeanu, V.; Borcea, C.; Negoita, F.; Petrascu, M. [NIPNE, Bucharest (Romania); Oberstedt, S.; Plompen, A.J.M. [JRC/IRMM, Geel (Belgium); Shcherbakov, O. [PNPI, Gatchina (Russian Federation); Fallot, M. [Subatech, 44 - Nantes (France); Smith, A.G.; Tsekhanovich, I. [Manchester Univ., Dept. of Physics and Astronomy (United Kingdom); Serot, O.; Sublet, J.C. [CEA Cadarache, DEN, 13 - Saint-Paul-lez-Durance (France); Perrot, L.; Tassan-Got, L. [IPNO, 91 - Orsay (France); Caillaud, T.; Giot, L.; Landoas, O.; Ramillon, J.M.; Rosse, B.; Thfoin, I. [CIMAP, 14 - Caen (France); Balanzat, E.; Bouffard, S.; Guillous, S.; Oberstedt, A. [Orebro Univ. (Sweden)

    2009-07-01

    The future Spiral-2 facility, dedicated to the production of intense radioactive ion beams, is based on a high-power superconducting driver Linac, delivering high-intensity deuteron, proton and heavy ion beams. These beams are particularly well suited to the production of neutrons in the 100 keV- 40 MeV energy range, a facility called 'Neutrons for Science' (NFS) will be built in the LINAG Experimental Area (LEA). NFS, operational in 2012, will be composed of a pulsed neutron beam for in-flight measurements and irradiation stations for activation measurements and material studies. Thick C and Be converters and a deuteron beam will produce an intense continuous neutron spectrum, while a thin {sup 7}Li target and a proton beam allow to generate quasi-mono-energetic neutrons. In the present work we show how the primary ion beam characteristics (energy, time resolution and intensity) are adequate to create a neutron time-of-flight facility delivering intense neutron fluxes in the 100 keV-40 MeV energy range. Irradiation stations for neutron, proton and deuteron reactions will also allow to perform cross-section measurements by means of the activation technique. Light-ion beams will be used to study radiation damage effects on materials for the nuclear industry. (authors)

  15. Spectra and absorbed dose by photo-neutrons in a solid water mannequin exposed to a Linac of 15 MV; Espectros y dosis absorbida por fotoneutrones en un maniqui de agua solida expuesta a una Linac de 15 MV

    Energy Technology Data Exchange (ETDEWEB)

    Benites R, J. [Centro Estatal de Cancerologia de Nayarit, Servicio de Seguridad Radiologica, Calz. de la Cruz 118 Sur, 63000 Tepic, Nayarit (Mexico); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. Postal 336, 98000 Zacatecas (Mexico); Velazquez F, J., E-mail: jlbenitesr@prodigy.net.mx [Universidad Autonoma de Nayarit, Posgrado en Ciencias Biologico Agropecuarias, Carretera Tepic-Compostela Km 9, 63780 Jalisco-Nayarit (Mexico)

    2012-10-15

    Using Monte Carlo methods was modeled a solid water mannequin; according to the ICRU 44 (1989), Tissue substitutes in radiation dosimetry and measurements, of the International Commission on Radiation Units and Measurements; Report 44. This material Wt 1 is made of H (8.1%), C (67.2%), N (2.4%), O (19.9%), Cl (0.1%), Ca (2.3%) and its density is of 1.02 gr/cm{sup 3}. The mannequin was put instead of the patient, inside the treatment room and the spectra and absorbed dose were determined by photo-neutrons exposed to a Linac of 15 MV. (Author)

  16. Study on Neutron Generation by Using Modified Prototype D-D Neutron Generator

    International Nuclear Information System (INIS)

    Kim, In-Jung; Kim, Suk-Kwon; Park, Chang-Su; Jung, Nam-Suk; Jung, Hwa-Dong; Chung, Kyoung-Jae; Hwang, Yong-Seok; Choi, H. D.

    2006-01-01

    The effects of Ti target thickness and deuteron beam energy on neutron generation in the modified prototype DD neutron generator were studied. Three kinds of Ti targets with the thickness of 10 μm, 40 μm and 1 mm were used. Deuteron beam energy was varied from 45 keV to 65 keV. The effects of target thickness and deuteron beam energy were evaluated for every set of experimental run and the results were discussed

  17. Survey of Neutron Generators for Active Interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Moss, Calvin Elroy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Myers, William L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sundby, Gary M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chichester, David L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Johnson, James P. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-05-02

    Some of these commercially available generators meet all of the requirements in Table 1, but there are other concerns. Most generators containing SF6 will be required to have the SF6 gas removed for shipping because of DOT regulations. However, Thermo Fisher has a DOT exemption. The P211 and B211 from Thermo Fisher meet the requirements listed in Table 1, but they are old designs and are no longer offered for sale. Also, they require 15 minutes or more of warmup before neutron output is available, and they lack a modern digital control. The nGen-300C from Starfire Industries is interesting because it is a portable system, but it uses the DD reaction for 2.5 MeV neutrons, which are not as penetrating as the 14 MeV neutrons from the DT reaction. The MP 320 from Thermo Fisher is another portable system, but the minimum pulse rate is 250 Hz, which is too fast for measurement of delayed neutrons and re-interrogation by delayed neutrons between pulses. The Genie 16 from Sodern (from France) probably meets the requirements, but the required power is probably too high for battery operation. The generators from Russia and China may be difficult to purchase, and service may not be available. The power required by some of these generators is low enough that batteries can be used. The portable units, nGen-300C and the MP320, could easily be operated with batteries. Other generators with low power requirements, as specified in the above vendors list, could possibly be operated with reason size batteries. The batteries do not need to be internal to the generator, but can be in a separate package. The availability of high capacity lithium batteries with sophisticated safety circuits makes battery operation more possible now than when lead acid batteries were used. The best path forward probably requires working with vendors of the existing systems. If Starfire Industries could be persuaded to put tritium in their nGen-300C generator, possibly in collaboration with a national

  18. Status of the intense pulsed neutron source

    International Nuclear Information System (INIS)

    Brown, B.S.; Carpenter, J.M.; Crawford, R.K.; Rauchas, A.V.; Schulke, A.W.; Worlton, T.G.

    1988-01-01

    IPNS is not unique in having concerns about the level of funding, and the future looks good despite these concerns. This report details the progress made at IPNS during the last two years. Other papers in these proceedings discuss in detail the status of the enriched uranium Booster target, the two instruments that are under construction, GLAD and POSY II, and a proposal for research on an Advanced Pulsed Neutron Source (ASPUN) that has been submitted to the Department of Energy (DOE). Further details on IPNS are available in the IPNS Progress Report 1987--1988, available by writing the IPNS Division Office. 9 refs., 3 tabs

  19. Linac 1, inner structure

    CERN Multimedia

    1968-01-01

    This photo shows the inner structure of Linac 1. As injector to the PS, and later to the Booster, Linac 1 accelerated protons to 50 MeV, but it has also accelerated heavier ions. Fitted with a 520 keV RFQ pre-injector (instead of the original Cockcroft-Walton generator), it delivered protons and heavy ions to LEAR, from 1982 to 1992. After 33 years of faithful service, Linac 1 was dismantled in 1992 to make room for Linac 3 (Pb ions).

  20. Livermore intense neutron source: design concepts

    International Nuclear Information System (INIS)

    Davis, J.C.; Anderson, J.D.; Booth, R.; Logan, C.M.; Osher, J.E.

    1975-07-01

    The Lawrence Livermore laboratory proposes to build an irradiation facility containing several 14 MeV T(d,n) neutron sources for materials damage experimentation. A source strength of 4 x 10 13 n/s can be produced with 400 keV D + beam on the tritium in titanium target system now used on the Livermore Rotating Target Neutron Source (RTNS). To produce the desired source strength an accelerator which can deliver 150 mA of 400 keV D + ions must be built. For the target to remain within the time-temperature regime of the present system it must have a diameter of 46 cm and rotate at 5000 rpm. With a beam spot 1 cm fwhm the useful target lifetime is expected to be the 100 hours typical of the present system. A maximum flux of 1.5 x 10 13 n/cm 2 s will be attainable over a sample 1 mm thick by 8 mm in diameter. (U.S.)

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

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  2. Neutron-irradiation facilities at the Intense Pulsed Neutron Source-I for fusion magnet materials studies

    International Nuclear Information System (INIS)

    Brown, B.S.; Blewitt, T.H.

    1982-01-01

    The decommissioning of reactor-based neutron sources in the USA has led to the development of a new generation of neutron sources that employ high-energy accelerators. Among the accelerator-based neutron sources presently in operation, the highest-flux source is the Intense Pulsed Neutron Source (IPNS), a user facility at Argonne National Laboratory. Neutrons in this source are produced by the interaction of 400 to 500 MeV protons with either of two 238 U target systems. In the Radiation Effects Facility (REF), the 238 U target is surrounded by Pb for neutron generatjion and reflection. The REF has three separate irradiation thimbles. Two thimbles provide irradiation temperatures between that of liquid He and several hundred degrees centigrade. The third thimble operates at ambient temperature. The large irradiation volume, the neutron spectrum and flux, the ability to transfer samples without warm up, and the dedication of the facilities during the irradiation make this ideally suited for radiation damage studies on components for superconducting fusion magnets. Possible experiments for fusion magnet materials are discussed on cyclic irradiation and annealing of stabilizers in a high magnetic field, mechanical tests on organic insulation irradiated at 4 K, and superconductors measured in high fields after irradiation

  3. Utilization of the intense pulsed neutron source (IPNS) at Argonne National Laboratory for neutron activation analysis

    International Nuclear Information System (INIS)

    Heinrich, R.R.; Greenwood, L.R.; Popek, R.J.; Schulke, A.W. Jr.

    1983-01-01

    The Intense Pulsed Neutron Source (IPNS) neutron scattering facility (NSF) has been investigated for its applicability to neutron activation analysis. A polyethylene insert has been added to the vertical hole VT3 which enhances the thermal neutron flux by a factor of two. The neutron spectral distribution at this position has been measured by the multiple-foil technique which utilized 28 activation reactions and the STAYSL computer code. The validity of this spectral measurement was tested by two irradiations of National Bureau of Standards SRM-1571 (orchard leaves), SRM-1575 (pine needles), and SRM-1645 (river sediment). The average thermal neutron flux for these irradiations normalized to 10 μamp proton beam is 4.0 x 10 11 n/cm 2 -s. Concentrations of nine trace elements in each of these SRMs have been determined by gamma-ray spectrometry. Agreement of measured values to certified values is demonstrated to be within experiment error

  4. Neutron generator power supply modeling in EMMA

    International Nuclear Information System (INIS)

    Robinson, A.C.; Farnsworth, A.V.; Montgomery, S.T.; Peery, J.S.; Merewether, K.O.

    1996-01-01

    Sandia National Laboratories has prime responsibility for neutron generator design and manufacturing, and is committed to developing predictive tools for modeling neutron generator performance. An important aspect of understanding component performance is explosively driven ferroelectric power supply modeling. EMMA (ElectroMechanical Modeling in ALEGRA) is a three dimensional compile time version of Sandia's ALEGRA code. The code is built on top of the general ALEGRA framework for parallel shock-physics computations but also includes additional capability for modeling the electric potential field in dielectrics. The overall package includes shock propagation due to explosive detonation, depoling of ferroelectric ceramics, electric field calculation and coupling with a general lumped element circuit equation system. The AZTEC parallel iterative solver is used to solve for the electric potential. The DASPK differential algebraic equation package is used to solve the circuit equation system. Sample calculations are described

  5. Intensity profiles behind a five-stage neutron interferometer

    International Nuclear Information System (INIS)

    Kischko, U.

    1983-01-01

    By means of the quantitative photography intensity profiles behind a five-stage ideal-crystal neutron interferometer at the thermal channel H25 of the high-flux reactor at the institute Laue-Langevin in Grenoble/France were dermined and compared with theoretical profiles. Contravily to X-rays by neutrons the hole Borrmann range is excited. This leads in the interference picture to superposition of several wave field components. It was shown that the spherical wave theory, as it was developed by W. Bauspiess, U. Bonse, and W. Graeff for the absorption-free neutron interferometer, describes well quantitatively the experimental intensity profiles. Expecially for the t-2t-t geometry the theoretically predicted focusing was confirmed. For the H-beam the intensity profile is symmetric and spatially limited; the O-beam is asymetric with intensities decreasing slowly up to the boundary. Geometrical differences within single stages lead to unique changes in the intensity profile. The pigtail pattern leading in the past to some puzzle guessing could be explained by the influence of geometrical defocusings on the phase shift. Important conclusions for the geometrical tolerances, which have to be regarded in the construction of neutron interferometers, could be obtained. (orig.) [de

  6. Linac-augmented light sources : an incremental concept for enhancing the capabilities of existing 3rd-generation storage rings

    International Nuclear Information System (INIS)

    Lewellen, J. W.

    2003-01-01

    Planned and proposed 4th-generation x-ray sources, such as energy-recovery linacs (ERLs) and single-pass x-ray free-electron lasers (X-FELs) offer a number of potential advantages, including small source size, higher peak brightness, ultrashort pulses, and potentially temporally and transversely coherent pulses. While offering unique capabilities, such facilities will also offer several important limitations, including limited numbers of user beamlines (for FELs) and a pulse-repetition rate that may be too high for many dynamics experiments (ERLs). In addition, there are many technical challenges associated with both types of facilities. A third type of facility, exemplified by the Short Pulse Photon Source (SPPS) at SLAC [1], would support neither a large number of users simultaneously nor generate coherent pulses, but would generate very intense, short x-ray pulses. Such a facility could serve as the starting point for either an ERL or an X-FEL, or a combined, hybrid machine. For the foreseeable future, however, existing 3rd-generation light source storage rings, such as the Advanced Photon Source, will continue to play important roles in supporting scientific research utilizing high-brightness x-rays. Existing facilities offer the powerful combination of a large number of user beamlines, efficient use of electron beam energy, and established user communities, and a program of incremental investment in, and improvements to, these facilities should continue to pay dividends into the future. This document discusses potential upgrade paths based on the Advanced Photon Source (APS) as a model 3rd-generation facility. If existing 3rd-generation facilities are to remain centers of excellence for light source-based research into the future, they must not only maintain and enhance their support of their existing user base, but also seek to expand their capabilities to support additional classes of users. There are several paths available toward this goal. The APS is

  7. Measurementof photo-neutron dose from an 18-MV medical linac using a foil activation method in view of radiation protection of patients

    International Nuclear Information System (INIS)

    Yuecel, Haluk; Kolbasi, Asuman; Yueksel, Alptug Oezer; Cobanbas, Ibrahim; Kaya, Vildan

    2016-01-01

    High-energy linear accelerators are increasingly used in the medical field. However, the unwanted photo-neutrons can also be contributed to the dose delivered to the patients during their treatments. In this study, neutron fluxes were measured in a solid water phantom placed at the isocenter 1-m distance from the head of an 18-MV linac using the foil activation method. The produced activities were measured with a calibrated well-type Ge detector. From the measured fluxes, the total neutron fluence was found to be (1.17 ± 0.06) X 10 7 n/cm 2 per Gy at the phantom surface in a 20 X 20 cm 2 X-ray field size. The maximum photo-neutron dose was measured to be 0.67 ± 0.04 mSv/Gy at d max = 5 cm depth in the phantom at isocenter. The present results are compared with those obtained for different field sizes of 10 X 10cm 2 , 15 X 15cm 2 , and 20 X 20cm 2 from 10-, 15-, and 18-MV linacs. Additionally, ambient neutron dose equivalents were determined at different locations in the room and they were found to be negligibly low. The results indicate that the photo-neutron dose at the patient position is not a negligible fraction of the therapeutic photon dose. Thus, there is a need for reduction of the contaminated neutron dose by taking some additional measures, for instance, neutron absorbing-protective materials might be used as aprons during the treatment

  8. Development of a D-D Neutron Generator

    International Nuclear Information System (INIS)

    Kim, In Jung; Jung, Hwa Dong; Park, Chang Su; Jung, Nam Suk; Jung, Soon Wook; Hwang, Y. S.; Choi, H. D.

    2007-01-01

    To enhance neutron yield, the ion source of the D-D neutron generator is replaced by a large current helicon plasma ion source. Current and energy of deuteron beam are increased, and hence neutron yield is enhanced. The maximum neutron yield is 2x10 8 n/s

  9. Performance of the intense pulsed neutron source accelerator system

    International Nuclear Information System (INIS)

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

    1983-01-01

    The Intense Pulsed Neutron Source (IPNS) facility has now been operating in a routine way for outside users since November 1, 1981. From that date through December of 1982, the accelerator system was scheduled for neutron science for 4500 hours. During this time the accelerator achieved its short-term goals by delivering about 380,000,000 pulses of beam totaling over 6 x 10 20 protons. The changes in equipment and operating practices that evolved during this period of intense running are described. The intensity related instability threshold was increased by a factor of two and the accelerator beam current has been ion source limited. Plans to increase the accelerator intensity are also described. Initial operating results with a new H - ion source are discussed

  10. Operational experience with the Fermilab Linac

    International Nuclear Information System (INIS)

    Allen, L.J.; Lennox, A.J.; Schmidt, C.W.

    1992-01-01

    The Fermilab 200-MeV Linac has been in operation for nearly 22 years as a proton injector to the Booster synchrotron. It presently accelerates H - ions to 200 MeV for charge-exchange injection into the Booster and to 66 MeV for the production of neutrons at the Neutron Therapy Facility (NTF). The beam intensity is typically 35 mA with pulse widths of 30 μsec for the Booster for high energy physics and 57 μsec for NTF at a maximum of 15 pulses per sec. During a typical physics run of nine to twelve months, beam is available for greater than 98% of the scheduled time. The Linac history, operation, tuning, stability and reliability will be discussed. (Author) 15 refs., 2 tabs

  11. Neutron PSDs for the next generation of spallation neutron sources

    CERN Document Server

    Eijk, C W

    2002-01-01

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

  12. Pulsed neutron intensity from rectangular shaped light water moderator with fast-neutron reflector

    International Nuclear Information System (INIS)

    Kiyanagi, Yoshiaki; Iwasa, Hirokatsu

    1982-01-01

    With a view to enhancing the thermal-neutron intensity obtained from a pulsed neutron source, an experimental study has been made to determine the optimum size of a rectangular shaped light water moderator provided with fast neutron reflector of beryllium oxide or graphite, and decoupled thermal-neutronically by means of Cd sheet. The optimum dimensions for the moderator are derived for the neutron emission surface and the thickn ess, for the cases in which the neutron-producing target is placed beneath the moderator (''wing geometry'') or immediately behind the moderator (''slab geometry''). The major conclusions drawn from the experimental results are as follows. The presence of the Cd decoupler inserted between the moderator and reflector prevent the enhancement of thermal-neutron emission time gained by the provision of reflector. With a graphite reflector about 14 cm thick, (a) the optimum area of emission surface would be 25 x 25 cm 2 for wing geometry and still larger for slab geometry, and (b) the optimum moderator thickness would be 5.5 cm for slab geometry and 8.5 cm for wing geometry. It is thus concluded that a higher neutron emission intensity can be obtained with slab than with wing geometry provided that a large emission surface can be adopted for the moderator. (author)

  13. A Proposal for a Next Generation European Neutron Source

    International Nuclear Information System (INIS)

    Andersen, K.H.; Carlile, C.J.

    2016-01-01

    We argue that it is not too early to begin the planning process for a next generation neutron source for Europe, even as the European Spallation Source is being constructed. We put forward three main arguments. Firstly, nowadays the period between the first scientific concept of a new facility being proposed and its actual realisation is approaching half a century. We show evidence for this. Secondly, there is a straightforward development of the short pulse/long pulse spallation concepts that will deliver gains in neutron brightness of more than a factor 30 over what the ESS will soon deliver and provide the optimum balance between resolution and intensity. We describe our concept, which is a spallation source where the proton pulse length is matched to the moderating time of slow neutrons. Thirdly, when we look at our colleagues in astronomy and high energy physics, we see that they have a totally different, more global and more ambitious approach to the coming generations of large facilities. We argue that it is time for the neutron community not simply to rest upon its laurels and take what is given but to be proactive.. (paper)

  14. Intense neutron source: high-voltage power supply specifications

    International Nuclear Information System (INIS)

    Riedel, A.A.

    1980-08-01

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

  15. SU-E-T-267: Construction and Evaluation of a Neutron Wall to Shield a 15 MV Linac in a Low-Energy Vault.

    Science.gov (United States)

    Speiser, M; Hager, F; Foster, R; Solberg, T

    2012-06-01

    To design and quantify the shielding efficacy of an inner Borated Polyethylene (BPE)wall for a 15 MV linac in a low energy vault. A Varian TrueBeam linac with a maximum photon energy of 15 MV was installed in asmaller, preexisting vault. This vault originally housed a low-energy machine and did not havesufficient maze length recommended for neutron attenuation. Effective dose rate calculationswere performed using the Modified Kersey's Method as detailed in NCRP Report No. 151 andfound to be unacceptably high. An initial survey following the machine installation confirmedthese calculations. Rather than restrict the linac beam energy to 10 MV, BPE was investigatedas a neutron moderating addition. An inner wall and door were planned and constructed using4'×8'×1″ thick 5% BPE sheets. The resulting door and wall had 2″ of BPE; conduits and ductwork were also redesigned and shielded. A survey was conducted following construction of thewall. The vault modification reduced the expected effective dose at the vault door from 36.23to 0.010 mSv/week. As specific guidelines for vault modification are lacking, this project quantitativelydemonstrates the potential use of BPE for vault modification. Such modifications may provide alow-cost shielding solution to allow for the use of high energy modes in smaller treatment vaults. © 2012 American Association of Physicists in Medicine.

  16. Spectra and neutron dose of an 18 MV Linac using two geometric models of the head; Espectros y dosis por neutrones de un Linac de 18 MV usando dos modelos geometricos del cabezal

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, M. T.; Pino, F.; Barros, H.; Sajo-Bohus, L. [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Sartenejas, Baruta 1080-A, Caracas (Venezuela, Bolivarian Republic of); Davila, J. [Fisica Medica C. A., Av. Francisco de Miranda s/n, Los Palos Grandes, 1060 Miranda (Venezuela, Bolivarian Republic of); Salcedo, E. [Centro Medico Docente La Trinidad, Av. de El Haltillo, Caracas (Venezuela, Bolivarian Republic of); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Benites R, J. L., E-mail: mariate9590@gmail.com [Centro de Cancerologia de Nayarit, Servicio de Seguridad Radiologica, Calz. de la Cruz 118 Sur, 63000 Tepic, Nayarit (Mexico)

    2015-10-15

    Full text: Using the Monte Carlo method, by MCNP5 code, simulations were performed with different source terms and 2 geometric models of the head to obtain spectra in energy, flow and doses of photo-neutrons at different positions on the stretcher and in the radiotherapy room. The simplest model was a spherical shell of tungsten; the second was the complete model of a heterogeneous head of an accelerator Varian ix. In both models Tosi function was used as a source term. In addition, for the second model Sheikh-Bagheri distribution was used for photons and photo-neutrons were generated. Also in both models the radiotherapy room of Gurve group of the Teaching Medical Center La Trinidad was included, which is equipped with an accelerator Varian Clinic 2100. In this Center passive detectors PADC (Cr-39) were irradiated with neutron converters, with 18 MeV photons radiation. The measured neutron flow was compared with that obtained with Monte Carlo calculations. The Monte Carlo flows are similar to those measured at the isocenter. The simplest model underestimates the neutron flow compared with the calculated flows with the heterogeneous model of the head. (Author)

  17. D-D neutron generator development at LBNL.

    Science.gov (United States)

    Reijonen, J; Gicquel, F; Hahto, S K; King, M; Lou, T-P; Leung, K-N

    2005-01-01

    The plasma and ion source technology group in Lawrence Berkeley National Laboratory is developing advanced, next generation D-D neutron generators. There are three distinctive developments, which are discussed in this presentation, namely, multi-stage, accelerator-based axial neutron generator, high-output co-axial neutron generator and point source neutron generator. These generators employ RF-induction discharge to produce deuterium ions. The distinctive feature of RF-discharge is its capability to generate high atomic hydrogen species, high current densities and stable and long-life operation. The axial neutron generator is designed for applications that require fast pulsing together with medium to high D-D neutron output. The co-axial neutron generator is aimed for high neutron output with cw or pulsed operation, using either the D-D or D-T fusion reaction. The point source neutron generator is a new concept, utilizing a toroidal-shaped plasma generator. The beam is extracted from multiple apertures and focus to the target tube, which is located at the middle of the generator. This will generate a point source of D-D, T-T or D-T neutrons with high output flux. The latest development together with measured data will be discussed in this article.

  18. Overview of the Division 2351 Neutron Generator Test Facility waveform digitizing system. [Explosively activated neutron generators

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, T.C. Jr.

    1978-02-01

    All neutron generator waveforms from units tested at the SLA neutron generator test site are digitized and the digitized data stored in the CDC 6600 tape library for display and analysis using the CDC 6600 computer. The digitizing equipment consists mainly of seven Biomation Model 8100 transient recorders, Digital Equipment Corporation PDP 11/20 computer, RK05 disk, seven-track magnetic tape transport, and appropriate DEC and SLA controllers and interfaces. The PDP 11/20 computer is programmed in BASIC with assembly language drivers. In addition to digitizing waveforms, this equipment is used for other functions such as the automated testing of multiple-operation electronic neutron generators. Although other types of analysis have been done, the largest use of the digitized data has been for various types of graphical displays using the CDC 6600 and either the SD4020 or DX4460 plotters.

  19. Shielding calculations for the Intense Neutron Source Facility. Final report

    International Nuclear Information System (INIS)

    Battat, M.E.; Henninger, R.J.; Macdonald, J.L.; Dudziak, D.J.

    1978-06-01

    Results of shielding calculations for the Intnse Neutron Source (INS) facility are presented. The INS facility is designed to house two sources, each of which will produce D--T neutrons with intensities in the range from 1 to 3 x 10 15 n/s on a continuous basis. Topics covered include the design of the biological shield, use of two-dimensional discrete-ordinates results to specify the source terms for a Monte Carlo skyshine calculation, air activation, and dose rates in the source cell (after shutdown) due to activation of the biological shield

  20. Study of general digital DC/pulse neutron generator

    International Nuclear Information System (INIS)

    Li Gang; Liu Zheng; Li Wensheng; Liu Hanlin; Liu Linmao

    2014-01-01

    Preliminary experimental results of digital DC/pulse neutron generator based on a ceramic drive-in target neutron tube for explosives detection are presented. The generator is a portable and on-off neutron source, and it can be controlled by remote PC. The generator can produce DC neutrons, pulse neutrons and multiple pulse neutrons. The maximum neutron yield is about 2 × 10"8 n/s, the minimum pulse width is 10 μs and the maximum pulse frequency is 10 kHz. Neutron yield and time-spectrum is measured in China Academy of Engineering Physics. The generator is suitable for explosive detection with PFTNA technology, and it can be used in other areas such as reactor measurements and on-line industrial test systems. (authors)

  1. Method and apparatus for generating neutrons

    International Nuclear Information System (INIS)

    Cranberg, L.

    1978-01-01

    An apparatus and method for generating high-energy neutrons are disclosed. Neutron emissive target material is deposited on one or more surfaces on a rotatable, hollow, toroidal target support. The surfaces are bombarded by beams of ions of generally rectangular cross section, so that when the bombarded surfaces are viewed end-wise, a compact, generally square source of neutrons is provided, such as is required for collimation. A combination of molecular and atomic ions emitted from at least one conventional accelerator are passed through a magnetic field for the purpose of separating the ions into one homogeneous group of atomic and one homogeneous group of molecular ions before the ions are allowed to impinge on the target surfaces. One accelerator directs ions to each target surface as the target rotates. Coolant is directed through a cavity within the toroidal support for the purpose of cooling the target support and target material. A refrigerated surface is placed in close proximity to the target surface to condense vapors which might prove harmful to the target and for thermally cooling said target

  2. Neutron generator tube ion source control apparatus

    International Nuclear Information System (INIS)

    Bridges, J.R.

    1982-01-01

    A pulsed neutron well logging system includes a neutron generator tube of the deuterium-tritium accelerator type and an ion source control apparatus providing extremely sharply time-defined neutron pulses. A low voltage control pulse supplied to an input by timing circuits turns a power FET on via a buffer-driver whereby a 2000 volt pulse is produced in the secondary of a pulse transformer and applied to the ion source of the tube. A rapid fall in this ion source control pulse is ensured by a quenching circuit wherein a one-shot responds to the falling edge of the control pulse and produces a 3 microsecond delay to compensate for the propagation delay. A second one-shot is triggered by the falling edge of the output of the first one-shot and gives an 8 microsecond pulse to turn on the power FET which, via an isolation transformer turns on a series-connected transistor to ground the secondary of the pulse transformer and the ion source. (author)

  3. Intense resonance neutron source (IREN) - new pulsed source for nuclear physical and applied investigations

    International Nuclear Information System (INIS)

    Anan'ev, V.D.; Furman, W.I.; Kobets, V.V.; Meshkov, I.N.; Pyataev, V.G.; Shirkov, G.D.; Shvets, V.A.; Sumbaev, A.P.; Kuatbekov, R.P.; Tret'yakov, I.T.; Frolov, A.R.; Gurov, S.M.; Logachev, P.V.; Pavlov, V.M.; Skarbo, B.A.

    2005-01-01

    An accelerator-driven subcritical system (200 MeV electron linac + metallic plutonium subcritical core) IREN is constructed at the Joint Institute for Nuclear Research (JINR). The new pulsed neutron source IREN is optimized for maximal yield of resonance neutrons (1-10 5 eV). The S-band electron linac with a pulse duration near 200 ns, repetition rate up to 150 Hz and the mean beam power 10 kW delivers 200-MeV electrons onto a specially designed tungsten target (an electron-neutron converter) situated in the center of a very compact and fast subcritical assembly with K eff 15 per second. A mean fission power of the multiplying target is planned to be near 15 kW. The current status of the project is presented

  4. Overview of Neutron Science Project

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-01

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

  5. Overview of Neutron Science Project

    International Nuclear Information System (INIS)

    Mukaiyama, Takehiko

    1997-01-01

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

  6. Development of fast neutron radiography system based on portable neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Chia Jia, E-mail: gei-i-kani@hotmail.com; Nilsuwankosit, Sunchai, E-mail: sunchai.n@chula.ac.th [Department of Nuclear Engineering, Faculty of Engineering, Chulalongkorn University, Phayathai Rd., Patumwan, Bangkok, THAILAND 10330 (Thailand)

    2016-01-22

    Due to the high installation cost, the safety concern and the immobility of the research reactors, the neutron radiography system based on portable neutron generator is proposed. Since the neutrons generated from a portable neutron generator are mostly the fast neutrons, the system is emphasized on using the fast neutrons for the purpose of conducting the radiography. In order to suppress the influence of X-ray produced by the neutron generator, a combination of a shielding material sandwiched between two identical imaging plates is used. A binary XOR operation is then applied for combining the information from the imaging plates. The raw images obtained confirm that the X-ray really has a large effect and that XOR operation can help enhance the effect of the neutrons.

  7. Fermilab: Linac upgrade

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    The Fermilab linear accelerator (Linac) was conceived 20 years ago, produced its first 200 MeV proton beam on 30 November 1970 and has run without major interruption ever since. Demands have steadily increased through the added complexity of the downstream chain of accelerators and by the increased patient load of the Neutron Therapy Facility

  8. Drift tubes of Linac 2

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    With the advent of the 800 MeV PS Booster in 1972, the original injector of the PS, a 50 MeV Alvarez-type proton linac, had reached its limits, in terms of intensity and stability. In 1973 one therefore decided to build a new linac (Linac 2), also with a drift-tube Alvarez structure and an energy of 50 MeV. It had a new Cockcroft-Walton preinjector with 750 keV, instead of the previous one with 500 keV. Linac 2 was put into service in 1980. The old Linac 1 was then used for the study of, and later operation with, various types of ions. This picture shows Linac 2 drift-tubes, suspended on stems coming from the top, in contrast to Linac 1, where the drift-tubes stood on stems coming from the bottom.

  9. 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

  10. Indoor Fast Neutron Generator for Biophysical and Electronic Applications

    Science.gov (United States)

    Cannuli, A.; Caccamo, M. T.; Marchese, N.; Tomarchio, E. A.; Pace, C.; Magazù, S.

    2018-05-01

    This study focuses the attention on an indoor fast neutron generator for biophysical and electronic applications. More specifically, the findings obtained by several simulations with the MCNP Monte Carlo code, necessary for the realization of a shield for indoor measurements, are presented. Furthermore, an evaluation of the neutron spectrum modification caused by the shielding is reported. Fast neutron generators are a valid and interesting available source of neutrons, increasingly employed in a wide range of research fields, such as science and engineering. The employed portable pulsed neutron source is a MP320 Thermo Scientific neutron generator, able to generate 2.5 MeV neutrons with a neutron yield of 2.0 x 106 n/s, a pulse rate of 250 Hz to 20 KHz and a duty factor varying from 5% to 100%. The neutron generator, based on Deuterium-Deuterium nuclear fusion reactions, is employed in conjunction with a solid-state photon detector, made of n-type high-purity germanium (PINS-GMX by ORTEC) and it is mainly addressed to biophysical and electronic studies. The present study showed a proposal for the realization of a shield necessary for indoor applications for MP320 neutron generator, with a particular analysis of the transport of neutrons simulated with Monte Carlo code and described the two main lines of research in which the source will be used.

  11. Pulsed neutron generator for mass flow measurement using the pulsed neutron activation technique

    International Nuclear Information System (INIS)

    Rochau, G.E.; Hornsby, D.R.; Mareda, J.F.; Riggan, W.C.

    1980-01-01

    A high-output, transportable neutron generator has been developed to measure mass flow velocities in reactor safety tests using the Pulsed Neutron Activation (PNA) Technique. The PNA generator produces >10 10 14 MeV D-T neutrons in a 1.2 millisecond pulse. The Millisecond Pulse (MSP) Neutron Tube, developed for this application, has an expected operational life of 1000 pulses, and it limits the generator pulse repetition rate to 12 pulses/minute. A semiconductor neutron detector is included in the generator package to monitor the neutron output. The control unit, which can be operated manually or remotely, also contains a digital display with a BCD output for the neutron monitor information. The digital logic of the unit controls the safety interlocks and rejects transient signals which could accidently fire the generator

  12. Development of compact D-D neutron generator

    International Nuclear Information System (INIS)

    Das, Basanta Kumar; Das, Rashmita; Shyam, Anurag

    2011-12-01

    In recent years, due to specific features of compact neutron generators, their demand in elemental analysis and detection of the illicit materials has been increased in scientific community. Compact is size, controlled operation and radiation safety like features of neutron generator is suitable for research work with illicit materials. An accelerator based neutron generator can be operated in steady mode as well as in pulse mode. The main embodiment of this type of generator includes ion source, ion acceleration system and target. We are developing such type of neutron generator. This consists of one-in-house developed penning ion source, a single electrode acceleration gap and one deuterated titanium target or virgin titanium target. In this report, we will discuss various physics and technical issues related to the important components of this generator, operation of the generator and neutron detection. (author)

  13. Generation of laser-induced fast neutron and its application

    International Nuclear Information System (INIS)

    Cha, Hyung Ki; Lee, S.; Kwon, D.; Nam, S.; Park, S.; Rhee, Y.; Jung, Y.; Lee, K.; Cha, Y.; Kwon, S.; Lim, C.; Han, J.; Park, S.; Chung, C.

    2012-04-01

    The supply of high-efficiency neutron source is still problematic even though a fast neutron source is being accepted increasingly for industrial applications. Radioisotopes and a neutron tube are typically being used, but their neutron flux, lifetime, and price are the limiting factors for more diverse applications. As ultra high power, short pulse laser technologies have been developed, a neutron source generated via laser induced nuclear reaction comes to the fore. The laser induced neutron source has a high peak flux in comparison to the traditional neutron source and is like a point source with its diameter less than 1 mm. These properties can be utilized effectively for the analysis of pulsed fast neutron activation or the studies of a fast neutron material damage and/or recover. The purpose of R and D here is to develop a robust neutron source with a yield of 107 neutrons/s during 1st R and D stage ('07 ∼ '09) and to construct a stable laser neutron source in longer operation and to demonstrate its usefulness for a neutron activation analysis of explosive materials and a neutron impact analysis of crystalline in the second R and D stage ('10 ∼ '11)

  14. Electron linac injector developments

    International Nuclear Information System (INIS)

    Fraser, J.S.

    1986-01-01

    There is a continuing demand for improved injectors for electron linacs. Free-electron laser (FEL) oscillators require pulse trains of high brightness and, in some applications, high average power at the same time. Wakefield-accelerator and laser-acceleration experiments require isolated bunches of high peak brightness. Experiments with alkali-halide photoemissive and thermionic electron sources in rf cavities for injector applications are described. For isolated pulses, metal photocathodes (illuminated by intense laser pulses) are being employed. Reduced emittance growth in high-peak-current electron injectors may be achieved by linearizing the cavity electric field's radial component and by using high field strengths at the expense of lower shunt impedance. Harmonically excited cavities have been proposed for enlarging the phase acceptance of linac cavities and thereby reducing the energy spread produced in the acceleration process. Operation of injector linacs at a subharmonic of the main linac frequency is also proposed for enlarging the phase acceptance

  15. Proposal for an accelerator-based neutron generator

    International Nuclear Information System (INIS)

    Grand, P.

    1975-07-01

    An Accelerator-based Neutron Generator is described that consists of a 30-MeV deuteron linear accelerator using a flowing liquid lithium target. With a continuous deuteron current of 100 milliamperes, a source intensity of more than 10 16 neutrons per second will be produced. The neutrons will be emitted in a roughly collimated beam. The proposed facility can be divided into two areas: the 30-MeV linear accelerator and the multiple-target experimental area. The 30-MeV accelerator will consist of eight rf accelerating cavities in a single vacuum tank, each cavity being powered by its own rf power amplifier operating at 50 MHz. To shield the beam bunches from the rf field when it is in the decelerating direction, 66 ''drift tubes'' will be included; the drift-tube structures will include quadrupole magnets which will keep the beam focused. The accelerator will produce a continuous beam of 100 milliamperes. Beam power will thus be 3.0 megawatts; total power including rf losses in the accelerating cavities will be 4.5 megawatts. The injectors for the linear accelerator will be two 500-kV dc accelerators, one for injection of D + ions and the other for D - ions. They can be used simultaneously or one can serve as a spare in case of breakdown or maintenance of the other. (U.S.)

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  17. Generation of neutron standing waves at total reflection of polarized neutrons

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Nikitenko, Yu.V.; Kozhevnikov, S.V.; Radu, F.; Kruijs, R.; Rekveldt, M.Th.

    1999-01-01

    The regime of neutron standing waves at reflection of polarized thermal neutrons from the structure glass/Cu (1000 A Angstrom)/Ti (2000 A Angstrom)/Co (60 A Angstrom)/Ti (300 A Angstrom) in a magnetic field directed at an angle to the sample plane is realized. The intensity of neutrons with a particular spin projection on the external magnetic field direction appears to be a periodic function of the neutron wavelength and the glancing angle of the reflected beam. It is shown that the neutron standing wave regime can be a very sensitive method for the determination of changes in the spatial position of magnetic noncollinear layers. (author)

  18. X-Ray Measurements Of A Thermo Scientific P385 DD Neutron Generator

    International Nuclear Information System (INIS)

    Wharton, C. J.; Seabury, E. H.; Chichester, D. L.; Caffrey, A. J.; Simpson, J.; Lemchak, M.

    2011-01-01

    Idaho National Laboratory is experimenting with electrical neutron generators, as potential replacements for californium-252 radioisotopic neutron sources in its PINS prompt gamma-ray neutron activation analysis (PGNAA) system for the identification of military chemical warfare agents and explosives. In addition to neutron output, we have recently measured the x-ray output of the Thermo Scientific P385 deuterium-deuterium neutron generator. X rays are a normal byproduct from neutron generators, but depending on their intensity and energy, x rays can interfere with gamma rays from the object under test, increase gamma-spectrometer dead time, and reduce PGNAA system throughput. The P385 x-ray energy spectrum was measured with a high-purity germanium (HPGe) detector, and a broad peak is evident at about 70 keV. To identify the source of the x rays within the neutron generator assembly, it was scanned by collimated scintillation detectors along its long axis. At the strongest x-ray emission points, the generator also was rotated 60 deg. between measurements. The scans show the primary source of x-ray emission from the P385 neutron generator is an area 60 mm from the neutron production target, in the vicinity of the ion source. Rotation of the neutron generator did not significantly alter the x-ray count rate, and its x-ray emission appears to be axially symmetric. A thin lead shield, 3.2 mm (1/8 inch) thick, reduced the 70-keV generator x rays to negligible levels.

  19. Induction linacs

    International Nuclear Information System (INIS)

    Keefe, D.

    1986-07-01

    The principle of linear induction acceleration is described, and examples are given of practical configurations for induction linacs. These examples include the Advanced Technology Accelerator, Long Pulse Induction Linac, Radial Line Accelerator (RADLAC), and Magnetically-Insulated Electron-Focussed Ion Linac. A related concept, the auto accelerator, is described in which the high-current electron-beam technology in the sub-10 MeV region is exploited to produce electron beams at energies perhaps as high as the 100 to 1000 MeV range. Induction linacs for ions are also discussed. The efficiency of induction linear acceleration is analyzed

  20. Neutron multiplication in lead in the experiments with neutron generators

    International Nuclear Information System (INIS)

    Markovskij, D.V.

    1989-01-01

    A calculational analysis of neutron multiplication in lead, including the estimates of multiplication limits for the standard ENDF/BIV data set and the effects of various changes in the data themselves is performed. 10 refs, 5 figs

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

    Science.gov (United States)

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

    2017-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Čufar, Aljaž, E-mail: aljaz.cufar@ijs.si [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Batistoni, Paola [ENEA, Department of Fusion and Nuclear Safety Technology, I-00044 Frascati, Rome (Italy); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Conroy, Sean [Uppsala University, Department of Physics and Astronomy, PO Box 516, SE-75120 Uppsala (Sweden); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Ghani, Zamir [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Lengar, Igor [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Milocco, Alberto; Packer, Lee [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Pillon, Mario [ENEA, Department of Fusion and Nuclear Safety Technology, I-00044 Frascati, Rome (Italy); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Popovichev, Sergey [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Snoj, Luka [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

    2017-03-01

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

  3. Intense harmonic generation from various ablation media

    International Nuclear Information System (INIS)

    Ozaki, T.; Elouga, L.; Suzuki, M.; Kuroda, H.; Ganeev, R.A.

    2006-01-01

    Complete test of publication follows. High-order harmonic generation (HHG) is a unique source of coherent extreme ultraviolet (XUV) radiation, which can produce soft x-rays within the spectral 'water-window' (between 2.3 and 4.4 nm), and ultimately short pulses with attosecond duration. However, the intensity of present-day harmonics is still low, and serious applications will need an increase of the conversion efficiency. Instead of using gas media, one can also use ablation material, produced on solid targets using a low-intensity prepulse, as the nonlinear medium to generate high-order harmonics. Recently, we have successfully demonstrated the generation of up to the 63 rd harmonic (λ = 12.6 nm) of a Ti:sapphire laser radiation using boron ablation, and a strong enhancement in the intensity of the 13 th harmonic from indium ablation. These harmonics were generated with a modest laser (10 mJ, 150 fs) and with the pre-pulse to main pulse energy ratio constant. In this paper, we perform systematic investigations of ablation harmonics, using the 200 mJ, 30 fs Ti:sapphire beam line of the Canadian Advanced Laser Light Source (ALLS) facility. ALLS allows studying ablation harmonics over wider experimental parameters, and with independent control over the pre-pulse and main pulse energies. The 10 Hz, 200 mJ Ti:sapphire beam line of ALLS is divided into two beams. Each beam has its own energy control system, which allows independent control over the energy of each beam. One of the beams is used as a pre-pulse for creating ablation, which is focused onto the solid target without pulse compression, with pulse duration of 200 ps. The second beam is used as the main pulse for harmonic generation. The main pulse is delayed in time relative to the pre-pulse by propagating through an optical delay line, and then sent through a pulse compressor. The compressed pulse duration have typical pulse duration of 30 fs FWHM, which is then focused onto the ablation medium using MgF 2

  4. Development of a sealed-accelerator-tube neutron generator

    Science.gov (United States)

    Verbeke; Leung; Vujic

    2000-10-01

    Sealed-accelerator-tube neutron generators are being developed in Lawrence Berkeley National Laboratory (LBNL) for applications ranging from neutron radiography to boron neutron capture therapy and neutron activation analysis. The new generation of high-output neutron generators is based on the D-T fusion reaction, producing 14.1-MeV neutrons. The main components of the neutron tube--the ion source, the accelerator and the target--are all housed in a sealed metal container without external pumping. Thick-target neutron yield computations are performed in this paper to estimate the neutron yield of titanium and scandium targets. With an average deuteron beam current of 1 A and an energy of 120 keV, a time-averaged neutron production of approximately 10(14) n/s can be estimated for a tritiated target, for both pulsed and cw operations. In mixed deuteron/triton beam operation, a beam current of 2 A at 150 keV is required for the same neutron output. Recent experimental results on ion sources and accelerator columns are presented and discussed.

  5. Self-modulation of an intense electron beam in an injector of a linac with a feedback

    International Nuclear Information System (INIS)

    Ajzatskij, N.I.

    1989-01-01

    This paper reports the results of the analysis of the time structure of the beam versus the RF power supplied to the injector of the linac with a feedback. Using a nonstationary model of acceleration, we have performed a mathematical simulation of the dynamics of prebunched electron beam acceleration. The results of the mathematical simulation demonstrate that in the self-modulation acceleration regime of a linac with feedbacks there exists a possibility of adjusting the current pulse length, the pulse-to-pulse time being nearly the same. 4 refs., 2 figs

  6. Fusion neutron generation by high-repetitive target injection

    International Nuclear Information System (INIS)

    Kitagawa, Yoneyoshi

    2015-01-01

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

  7. Analysis of the neutron generation from a D-Li neutron source

    International Nuclear Information System (INIS)

    Gomes, I.

    1994-02-01

    The study of the neutron generation from the D-Li reaction is an important issue to define the optimum combination of the intervening parameters during the design phase of a D-Li neutron source irradiation facility. The major players in defining the neutron yield from the D-Li reaction are the deuteron incident energy and the beam current, provided that the lithium target is thick enough to stop all incident deuterons. The incident deuteron energy also plays a role on the angular distribution of the generated neutrons, on the energy distribution of the generated neutrons, and on the maximum possible energy of the neutrons. The D-Li reaction produces neutrons with energies ranging from eV's to several MeV's. The angular distribution of these neutrons is dependent on the energy of both, incident deuterons and generated neutrons. The deuterons lose energy interacting with the lithium target material in such a way that the energy of the deuterons inside the lithium target varies from the incident deuteron energy to essentially zero. The first part of this study focuses in analyzing the neutron generation rate from the D-Li reaction as a function of the intervening parameters, in defining the source term, in terms of the energy and angular distributions of the generated neutrons, and finally in providing some insights of the impact of varying input parameters on the generation rate and correlated distributions. In the second part an analytical description of the Monte Carlo sampling procedure of the neutron from the D-Li reaction is provided with the aim at further Monte Carlo transport of the D-Li neutrons

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  9. Area radiation monitor at the intense pulsed-neutron source

    International Nuclear Information System (INIS)

    Eichholz, J.J.; Lynch, F.J.; Mundis, R.L.; Howe, M.L.; Dolecek, E.H.

    1981-01-01

    A tissue-equivalent ionization chamber with associated circuitry has been developed for area radiation monitoring in the Intense Pulsed-Neutron Source (IPNS) facility at Argonne National Laboratory. The conventional chamber configuration was modified in order to increase the electric field and effective volume thereby achieving higher sensitivity and linearity. The instrument provides local and remote radiation level indications and a high level alarm. Twenty-four of these instruments were fabricated for use at various locations in the experimental area of the IPNS-1 facility

  10. Light ion linacs for medical applications

    International Nuclear Information System (INIS)

    Bradbury, J.N.; Knapp, E.A.; Nagle, D.E.

    1975-01-01

    Recent advances in linear accelerator technology point to the feasibility of designing and developing practical medical linacs for producing protons, neutrons, or π mesons for the radiation therapy of cancer. Additional uses of such linacs could include radioisotope production and charged particle radiography. For widespread utilization medical linacs must exhibit reasonable cost, compactness, reliability, and simplicity of operation. Possible extensions of current accelerator technology which might provide these characteristics are discussed in connection with linac design, fabrication techniques, materials, power sources, injectors, and particle collection and delivery systems. Parameters for a medical proton linac for producing pions are listed. (U.S.)

  11. Utilization of low voltage D-T neutron generators in neutron physics studies

    Energy Technology Data Exchange (ETDEWEB)

    Singkarat, S.

    1995-08-01

    In a small nuclear laboratory of a developing country a low voltage D-T neutron generator can be a very useful scientific apparatus. Such machines have been used successfully for more than 40 years in teaching and scientific research. The original continuous mode 150-kV D-T neutron generator has been modified to have also a capability of producing 2-ns pulsed neutrons. Together with a carefully designed 10 m long flight path collimator and shielding of a 25 cm diameter {center_dot} 10 cm thick BC-501 neutron detector, the pulsing system was successfully used for measuring the double differential cross-section (DDX) of natural iron for 14.1-MeV neutron from the angle of 30 deg to 150 deg in 10 deg steps. In order to extend the utility of the generator, two methods for converting the almost monoenergetic 14-MeV neutrons to monoenergetic neutrons of lower energy were proposed and tested. The first method uses a pulsed neutron generator and the second method uses an ordinary continuous mode generator. The latter method was successfully used to measure the scintillation light output of a 1.4 cm diameter spherical NE-213 scintillation detector. The neutron generator has also been used in the continuous search for improved neutron detection techniques. There is a proposal, based on Monte Carlo calculations, of using a scintillation fiber for a fast neutron spectrometer. Due to the slender shape of the fiber, the pattern of produced light gives a peak in the pulse height spectrum instead of the well-known rectangular-like distribution, when the fiber is bombarded end-on by a beam of 14-MeV neutrons. Experimental investigations were undertaken. Detailed investigations on the light transportation property of a short fiber were performed. The predicted peak has not yet been found but the fiber detector may be developed as a directional discrimination fast neutron detector. 18 refs.

  12. Mechanism of neutron generation in Z-pinches

    International Nuclear Information System (INIS)

    Vikhrev, V.V.

    1986-01-01

    The review of experimental and theoretical investigations in a mechanism of neutron generation in Z-pinches is presented. Special attention is paid to the thermonuclear mechanism of neutron generation occuring due to the formation of high-temperature plasma regions in Z-pinch sausage-type instabilities. This mechanism is shown to be predominant in charges with the neutron yield more than 10 9 per a charge. Experimental data, which are considered to be contradicting to thermonuclear nature of neutron radiation, are explained

  13. Neutron scattering in disordered alloys: coherent and incoherent intensities

    International Nuclear Information System (INIS)

    Mookerjee, A.; Yussouff, M.

    1985-02-01

    A priori it is not clear how to split the total intensity of thermal neutron scattering from disordered alloys into a coherent and an incoherent part. We present here a formalism to do this. The formalism is based on the augmented space technique introduced earlier by one of the authors. It includes disorder in mass, force constants and scattering lengths. A self-consistent CCPA which is tractable for realistic calculations is presented for the coherent and incoherent intensities. This is expected to prove useful in theoretically analysis data for alloys (e.g. Nisub(x)Ptsub(1-x), Nisub(x)Pdsub(1-x), Nisub(x)Crsub(1-x)) for which it is necessary to go beyond the usual single site CPAs for reliable accuracy. (author)

  14. Generation of intense transient magnetic fields

    International Nuclear Information System (INIS)

    Benjamin, R.F.

    1983-01-01

    In a laser system, the return current of a laser generated plasma is conducted near a target to subject that target to a magnetic field. The target may be either a small non-fusion object for testing under the magnetic field or a laser-fusion pellet. In the laser-fusion embodiment, the laser-fusion pellet is irradiated during the return current flow and the intense transient magnetic field is used to control the hot electrons thereof to hinder them from striking and heating the core of the irradiated laser-fusion pellet. An emitter, e.g. a microballoon of glass, metal or plastics, is subjected to a laser pulse to generate the plasma from which the return current flows into a wire cage or a coil and then to earth. (author)

  15. Associated-particle sealed-tube neutron generators and hodoscopes for NDA applications

    International Nuclear Information System (INIS)

    Rhodes, E.; Peters, C.W.

    1991-01-01

    With radioisotope sources, gamma-ray transmission hodoscopes can inspect canisters and railcars to monitor rocket motors, can detect nuclear warheads by their characteristic strong gamma-ray absorption, or can count nuclear warheads inside a missile by low-resolution tomography. Intrinsic gamma-ray radiation from warheads can also be detected in a passive mode. Neutron hodoscopes can use neutron transmission, intrinsic neutron emission, or reactions stimulated by a neutron source, in treaty verification roles. Gamma-ray and neutron hodoscopes can be combined with a recently developed neutron diagnostic probe system, based on a unique associated-particle sealed-tube neutron generator (APSTNG) that interrogates the object of interest with a low-intensity beam of 14-MeV neutrons, and that uses flight-time to electronically collimate transmitted neutrons and to tomographically image nuclides identified by reaction gamma-rays. Gamma-ray spectra of resulting neutron reactions identify nuclides associated with all major chemicals in chemical warfare agents, explosives, and drugs, as well as many pollutants and fissile and fertile special nuclear material. 5 refs., 12 figs

  16. Radiological safety aspects of the operation of neutron generators

    International Nuclear Information System (INIS)

    Boggs, R.F.

    1976-01-01

    The purpose of the manual is to provide some basic guidelines to persons with a minimum of training in radiological health or health physics, on some safety aspects of the operation of sealed-tube and Cockcroft-Walton type neutron generators. The manual does not state rules or regulations but presents a description of the most likely hazards. It is relevant to those relatively compact neutron generators which usually operate at less than 150-200 kV for the purpose of producing 14-MeV neutrons. The scope is limited to basic discussions of hazards and measurement techniques. Separate chapters are devoted to the characteristics and use of neutron generators; radiation hazards and safety considerations; radiation monitoring and interpretation of measurements; and requirements for an effective safety programme. Two appendices deal with non-radiation hazards and safety considerations, and with a neutron generator laboratory, respectively. An extensive list of bibliographic references is included

  17. Means and method for controlling the neutron output of a neutron generator tube

    International Nuclear Information System (INIS)

    Langford, O.M.; Peelman, H.E.

    1980-01-01

    A gas filled neutron tube in a nuclear well logging tool has a target an ion source voltage and a replenisher connected to ground. A negative high voltage is applied to the target by a power supply also providing a target current corresponding to the neutron output of the neutron generator tube. A constant current source provides a constant current. A network receiving the target current and the constant current provides a portion of the constant current as a replenisher current which is applied to the replenisher in a neutron generating tube. The network controls the magnitude of the replenisher current in accordance with the target current so as to control the neutron output of the neutron generating tube. (auth)

  18. The applied research program of the High Flux Neutron Generator at the National Nuclear Center, Havana

    International Nuclear Information System (INIS)

    Perez, G.; Martin, G.; Ceballos, C.; Padron, I.; Shtejer, K.; Perez, N.; Guibert, R.; Ledo, L.M.; Cruz Inclan, Carlos

    2001-01-01

    The Havana High Flux Neutron Generator facility is an intense neutron source based on a 20 mA duoplasmatron ion source and a 250 kV high voltage power supply. It has been installed in the Neutron Generator Laboratory at the Center of Applied Technologies and Nuclear Research in 1997. This paper deal outlined the future applied program to be carried out in this facility in the next years. The Applied Research Program consists on install two nuclear analytic techniques: the PELAN technique which uses the neutron generator in the pulse mode and the Low Energy PIXE technique which uses the same facility as a low energy proton accelerator for PIXE analysis. (author)

  19. Fission multipliers for D-D/D-T neutron generators

    International Nuclear Information System (INIS)

    Lou, T.P.; Vujic, J.L.; Koivunoro, H.; Reijonen, J.; Leung, K.-N.

    2003-01-01

    A compact D-D/D-T fusion based neutron generator is being designed at the Lawrence Berkeley National Laboratory to have a potential yield of 10 12 D-D n/s and 10 14 D-T n/s. Because of its high neutron yield and compact size (∼20 cm in diameter by 4 cm long), this neutron generator design will be suitable for many applications. However, some applications required higher flux available from nuclear reactors and spallation neutron sources operated with GeV proton beams. In this study, a subcritical fission multiplier with k eff of 0.98 is coupled with the compact neutron generators in order to increase the neutron flux output. We have chosen two applications to show the gain in flux due to the use of fission multipliers--in-core irradiation and out-of-core irradiation. For the in-core irradiation, we have shown that a gain of ∼25 can be achieved in a positron production system using D-T generator. For the out-of-core irradiation, a gain of ∼17 times is obtained in Boron Neutron Capture Therapy (BNCT) using a D-D neutron generator. The total number of fission neutrons generated by a source neutron in a fission multiplier with k eff is ∼50. For the out-of-core irradiation, the theoretical maximum net multiplication is ∼30 due to the absorption of neutrons in the fuel. A discussion of the achievable multiplication and the theoretical multiplication will be presented in this paper

  20. Wakefields in SLAC linac collimators

    Directory of Open Access Journals (Sweden)

    A. Novokhatski

    2014-12-01

    Full Text Available When a beam travels near collimator jaws, it gets an energy loss and a transverse kick due to the backreaction of the beam field diffracted from the jaws. The effect becomes very important for an intense short bunch when a tight collimation of the background beam halo is required. In the Linac Coherent Light Source at SLAC a collimation system is used to protect the undulators from radiation due to particles in the beam halo. The halo is most likely formed from gun dark current or dark current in some of the accelerating sections. However, collimators are also responsible for the generation of wake fields. The wake field effect from the collimators not only brings an additional energy jitter and change in the trajectory of the beam, but it also rotates the beam on the phase plane, which consequently leads to a degradation of the performance of the Free Electron Laser at the Linac Coherent Light Source. In this paper, we describe a model of the wake field radiation in the SLAC linac collimators. We use the results of a numerical simulation to illustrate the model. Based on the model, we derive simple formulas for the bunch energy loss and the average kick. We also present results from experimental measurements that confirm our model.

  1. Generation of laser-induced fast neutron and its application

    International Nuclear Information System (INIS)

    Cha, Hyung Ki; Kwon, D. H.; Nam, S. M.

    2010-04-01

    The supply of high-efficiency neutron source is still problematic even though a fast neutron source is being accepted increasingly for industrial applications. Radioisotopes and a neutron tube are typically being used, but their neutron flux, lifetime, and price are the limiting factors for more diverse applications. As ultra high power, short pulse laser technologies have been developed, a neutron source generated via laser induced nuclear reaction comes to the fore. The laser induced neutron source has a high peak flux in comparison to the traditional neutron source and is like a point source with its diameter less than 1 mm. These properties can be utilized effectively for the analysis of pulsed fast neutron activation or the studies of a fast neutron material damage and/or recover. The purpose of R and D here is to develop a robust neutron source with a yield of 10 7 neutrons/s, and to carry out a preliminary research for application study in the next research stage

  2. Electron linacs

    Energy Technology Data Exchange (ETDEWEB)

    Loew, G A; Schriber, S O [ed.

    1976-11-01

    A study was made of the present status of the thousand or so electron linacs in the world, and future trends in the field. These machines were classified according to their use: medical, industrial, and nuclear physics. In the medical category, two types of electron linacs are discussed: the conventional ones which are used for x-ray and electron therapy, and those which may in the future be used for negative pion therapy. Industrial machines discussed include linacs for radiographic and other specialized applications. In the nuclear physics category, the status of conventional low- and medium-energy as well as high duty cycle linacs is reviewed. The question of how one might obtain a c-w, 1 GeV, 100..mu..A electron linac is raised, and various options using recirculation and stretchers are examined. In this connection, the status of rf superconductivity is summarized. A review is given of linacs for injectors into synchrotrons and e/sup +-/ storage rings, and recent work done to upgrade the only multi-GeV linac, namely SLAC, is described.

  3. Electron linacs

    International Nuclear Information System (INIS)

    Loew, G.A.

    1976-01-01

    To study the present status of the thousand or so electron linacs in the world, and future trends in the field, we have classified these machines according to their use: medical, industrial, and nuclear physics. In the medical category, two types of electron linacs are discussed: the conventional ones which are used for X-ray and electron therapy, and those which may in the future be used for negative pion therapy. The section on industrial machines includes linacs for radiographic and other specialized applications. In the nuclear physics category, the status of conventional low- and medium-energy as well as high duty cycle linacs is reviewed. The question of how one might obtain a C.W., 1 GeV, 100 μA electron linac is raised and various options using recirculation and stretchers are examined. In this connection, the status of RF superconductivity is summarized. Following, there is a review of linacs for injectors into synchrotrons and e +- storage rings. The paper ends with a description of recent work done to upgrade the only multi-GeV linac, namely SLAC. (author)

  4. Research and development activities of a neutron generator facility

    International Nuclear Information System (INIS)

    Darsono Sudjatmoko; Pramudita Anggraita; Sukarman Aminjoyo

    2000-01-01

    The neutron generator facility at YNRC is used for elemental analysis, nuclear data measurement and education. In nuclear data measurement the focus is on re-evaluating the existing scattered nuclear activation cross-section to obtain systematic data for nuclear reactions such as (n,p), (n,α), and (n,2n). In elemental analysis it is used for analyzing the Nitrogen (N), Phosphor (P) and Potassium (K) contents in chemical and natural fertilizers (compost), protein in rice, soybean, and corn and pollution level in rivers. The neutron generator is also used for education and training of BATAN staff and university students. The facility can also produce neutron generator components. (author)

  5. Generating energy dependent neutron flux maps for effective ...

    African Journals Online (AJOL)

    For activation analysis and irradiation scheme of miniature neutron source reactor, designers or engineers usually require information on thermal neutron flux levels and other energy group flux levels (such as fast, resonance and epithermal). A methodology for readily generating such flux maps and flux profiles for any ...

  6. Note: Coincidence measurements of 3He and neutrons from a compact D-D neutron generator

    Science.gov (United States)

    Ji, Q.; Lin, C.-J.; Tindall, C.; Garcia-Sciveres, M.; Schenkel, T.; Ludewigt, B. A.

    2017-05-01

    Tagging of neutrons (2.45 MeV) with their associated 3He particles from deuterium-deuterium (D-D) fusion reactions has been demonstrated in a compact neutron generator setup enabled by a high brightness, microwave-driven ion source with a high fraction of deuterons. Energy spectra with well separated peaks of the D-D fusion reaction products, 3He, tritons, and protons, were measured with a silicon PIN diode. The neutrons were detected using a liquid scintillator detector with pulse shape discrimination. By correlating the 3He detection events with the neutron detection in time, we demonstrated the tagging of emitted neutrons with 3He particles detected with a Si PIN diode detector mounted inside the neutron generator vacuum vessel.

  7. Neutron Science Project at JAERI

    International Nuclear Information System (INIS)

    Oyama, Yukio

    1998-01-01

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

  8. Neutron Science Project at JAERI

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-03-01

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

  9. Development of high flux thermal neutron generator for neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Vainionpaa, Jaakko H., E-mail: hannes@adelphitech.com [Adelphi Technology, 2003 E Bayshore Rd, Redwood City, CA 94063 (United States); Chen, Allan X.; Piestrup, Melvin A.; Gary, Charles K. [Adelphi Technology, 2003 E Bayshore Rd, Redwood City, CA 94063 (United States); Jones, Glenn [G& J Jones Enterprice, 7486 Brighton Ct, Dublin, CA 94568 (United States); Pantell, Richard H. [Department of Electrical Engineering, Stanford University, Stanford, CA (United States)

    2015-05-01

    The new model DD110MB neutron generator from Adelphi Technology produces thermal (<0.5 eV) neutron flux that is normally achieved in a nuclear reactor or larger accelerator based systems. Thermal neutron fluxes of 3–5 · 10{sup 7} n/cm{sup 2}/s are measured. This flux is achieved using four ion beams arranged concentrically around a target chamber containing a compact moderator with a central sample cylinder. Fast neutron yield of ∼2 · 10{sup 10} n/s is created at the titanium surface of the target chamber. The thickness and material of the moderator is selected to maximize the thermal neutron flux at the center. The 2.5 MeV neutrons are quickly thermalized to energies below 0.5 eV and concentrated at the sample cylinder. The maximum flux of thermal neutrons at the target is achieved when approximately half of the neutrons at the sample area are thermalized. In this paper we present simulation results used to characterize performance of the neutron generator. The neutron flux can be used for neutron activation analysis (NAA) prompt gamma neutron activation analysis (PGNAA) for determining the concentrations of elements in many materials. Another envisioned use of the generator is production of radioactive isotopes. DD110MB is small enough for modest-sized laboratories and universities. Compared to nuclear reactors the DD110MB produces comparable thermal flux but provides reduced administrative and safety requirements and it can be run in pulsed mode, which is beneficial in many neutron activation techniques.

  10. Nuclear Fusion Effects Induced in Intense Laser-Generated Plasmas

    Directory of Open Access Journals (Sweden)

    Lorenzo Torrisi

    2013-01-01

    Full Text Available Deutered polyethylene (CD2n thin and thick targets were irradiated in high vacuum by infrared laser pulses at 1015W/cm2 intensity. The high laser energy transferred to the polymer generates plasma, expanding in vacuum at supersonic velocity, accelerating hydrogen and carbon ions. Deuterium ions at kinetic energies above 4 MeV have been measured by using ion collectors and SiC detectors in time-of-flight configuration. At these energies the deuterium–deuterium collisions may induce over threshold fusion effects, in agreement with the high D-D cross-section valuesaround 3 MeV energy. At the first instants of the plasma generation, during which high temperature, density and ionacceleration occur, the D-D fusions occur as confirmed by the detection of mono-energetic protonsand neutrons with a kinetic energy of 3.0 MeV and 2.5 MeV, respectively, produced by the nuclear reaction. The number of fusion events depends strongly on the experimental set-up, i.e. on the laser parameters (intensity, wavelength, focal spot dimension, target conditions (thickness, chemical composition, absorption coefficient, presence of secondary targets and used geometry (incidence angle, laser spot, secondary target positions.A number of D-D fusion events of the order of 106÷7 per laser shot has been measured.

  11. The neutron production rate measurement of an indigenously developed compact D-D neutron generator

    Directory of Open Access Journals (Sweden)

    Das Basanta Kumar

    2013-01-01

    Full Text Available One electrostatic accelerator based compact neutron generator was developed. The deuterium ions generated by the ion source were accelerated by one accelerating gap after the extraction from the ion source and bombarded to a target. Two different types of targets, the drive - in titanium target and the deuteriated titanium target were used. The neutron generator was operated at the ion source discharge potential at +Ve 1 kV that generates the deuterium ion current of 200 mA at the target while accelerated through a negative potential of 80 kV in the vacuum at 1.3×10-2 Pa filled with deuterium gas. A comparative study for the neutron yield with both the targets was carried out. The neutron flux measurement was done by the bubble detectors purchased from Bubble Technology Industries. The number of bubbles formed in the detector is the direct measurement of the total energy deposited in the detector. By counting the number of bubbles the total dose was estimated. With the help of the ICRP-74 neutron flux to dose equivalent rate conversion factors and the solid angle covered by the detector, the total neutron flux was calculated. In this presentation the operation of the generator, neutron detection by bubble detector and estimation of neutron flux has been discussed.

  12. Intensity enhancement of cold neutrons from a coupled liquid-hydrogen moderator for pulsed cold neutron sources

    International Nuclear Information System (INIS)

    Ogawa, Y.; Kiyanagi, Y.; Kosugi, N.; Iwasa, H.; Furusaka, M.; Watanabe, N.

    1999-01-01

    In order to obtain higher cold neutron intensity from a coupled liquid-hydrogen moderator with a premoderator for pulsed cold neutron sources, we examined a partial enhancement method, namely, narrow beam extraction for both a flat liquid-hydrogen moderator and a single-groove one. Combined with the narrow beam extraction, which is especially suitable for small-angle scattering and neutron reflectometry experiments, a single-groove moderator provides higher intensity, by about 30%, than a flat-surface moderator at the region of interest on a viewed surface. The effect of double-side beam extraction from such moderators on the intensity gain factor is also discussed. (author)

  13. Feasibility of sealed D-T neutron generator as neutron source for liver BNCT and its beam shaping assembly.

    Science.gov (United States)

    Liu, Zheng; Li, Gang; Liu, Linmao

    2014-04-01

    This paper involves the feasibility of boron neutron capture therapy (BNCT) for liver tumor with four sealed neutron generators as neutron source. Two generators are placed on each side of the liver. The high energy of these emitted neutrons should be reduced by designing a beam shaping assembly (BSA) to make them useable for BNCT. However, the neutron flux decreases as neutrons pass through different materials of BSA. Therefore, it is essential to find ways to increase the neutron flux. In this paper, the feasibility of using low enrichment uranium as a neutron multiplier is investigated to increase the number of neutrons emitted from D-T neutron generators. The neutron spectrum related to our system has a proper epithermal flux, and the fast and thermal neutron fluxes comply with the IAEA recommended values. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Superconducting linac

    International Nuclear Information System (INIS)

    Bollinger, L.M.; Shepard, K.W.; Wangler, T.P.

    1978-01-01

    This project has two goals: to design, build, and test a small superconducting linac to serve as an energy booster for heavy ions from an FN tandem electrostatic accelerator, and to investigate various aspects of superconducting rf technology. The main design features of the booster are described, a status report on various components (resonators, rf control system, linac control system, cryostats, buncher) is given, and plans for the near future are outlined. Investigations of superconducting-linac technology concern studies on materials and fabrication techniques, resonator diagnostic techniques, rf-phase control, beam dynamics computer programs, asymmetry in accelerating field, and surface-treatment techniques. The overall layout of the to-be-proposed ATLAS, the Argonne Tandem-Linac Accelerator System, is shown; the ATLAS would use superconducting technology to produce beams of 5 to 25 MeV/A. 6 figures

  15. Portable Neutron Generator with 9-Section Silicon $\\alpha $-Detector

    CERN Document Server

    Bystritsky, V M; Kadyshevskij, V G; Khasaev, T O; Kobzev, A P; Presnyakov, Yu K; Rogov,Yu N; Ryzhkov, V I; Sapozhnikov, M G; Sissakian, A N; Slepnev, V M; Zamyatin, N I

    2006-01-01

    The characteristics of the portable neutron generator with a built-in $\\alpha $-detector are presented. Based on the "tagged" neutron method (TNM) the generator ~is being used for identification of ~the hidden chemical compounds. One of the special features of such generators compared to generators traditionally used and produced in industry is that the generator is a source of monoenergetic "tagged" 14.1 MeV neutrons produced in the binary nuclear reaction $d+t \\to \\alpha $ (3.5 MeV) $+n$ (14.1~MeV). Unambiguous information about the time and direction of the neutron emitted from the target can be obtained by recording an $\\alpha $ particle by the multi-pixel $\\alpha $-detector placed inside the neutron tube. The study of the "tagged" neutron method (TNM) shows that the use of the ($\\alpha $--$\\gamma $) coincidence reduces the gamma background induced by scattered neutrons by a factor of more than 200, which allows the detection and identification of small quantities of explosives, drugs, and toxic agents. T...

  16. Turbulence generation through intense kinetic energy sources

    Science.gov (United States)

    Maqui, Agustin F.; Donzis, Diego A.

    2016-06-01

    Direct numerical simulations (DNS) are used to systematically study the development and establishment of turbulence when the flow is initialized with concentrated regions of intense kinetic energy. This resembles both active and passive grids which have been extensively used to generate and study turbulence in laboratories at different Reynolds numbers and with different characteristics, such as the degree of isotropy and homogeneity. A large DNS database was generated covering a wide range of initial conditions with a focus on perturbations with some directional preference, a condition found in active jet grids and passive grids passed through a contraction as well as a new type of active grid inspired by the experimental use of lasers to photo-excite the molecules that comprise the fluid. The DNS database is used to assert under what conditions the flow becomes turbulent and if so, the time required for this to occur. We identify a natural time scale of the problem which indicates the onset of turbulence and a single Reynolds number based exclusively on initial conditions which controls the evolution of the flow. It is found that a minimum Reynolds number is needed for the flow to evolve towards fully developed turbulence. An extensive analysis of single and two point statistics, velocity as well as spectral dynamics and anisotropy measures is presented to characterize the evolution of the flow towards realistic turbulence.

  17. High yield neutron generators using the DD reaction

    Energy Technology Data Exchange (ETDEWEB)

    Vainionpaa, J. H.; Harris, J. L.; Piestrup, M. A.; Gary, C. K.; Williams, D. L.; Apodaca, M. D.; Cremer, J. T. [Adelphi technology, 2003 E. Bayshore Rd. 94061, Redwood City, CA (United States); Ji, Qing; Ludewigt, B. A. [Lawrence Berkeley National Lab, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Jones, G. [G and J Enterprise, 1258 Quary Ln, Suite F, Pleasanton California 94566 (United States)

    2013-04-19

    A product line of high yield neutron generators has been developed at Adelphi technology inc. The generators use the D-D fusion reaction and are driven by an ion beam supplied by a microwave ion source. Yields of up to 5 Multiplication-Sign 10{sup 9} n/s have been achieved, which are comparable to those obtained using the more efficient D-T reaction. The microwave-driven plasma uses the electron cyclotron resonance (ECR) to produce a high plasma density for high current and high atomic ion species. These generators have an actively pumped vacuum system that allows operation at reduced pressure in the target chamber, increasing the overall system reliability. Since no radioactive tritium is used, the generators can be easily serviced, and components can be easily replaced, providing essentially an unlimited lifetime. Fast neutron source size can be adjusted by selecting the aperture and target geometries according to customer specifications. Pulsed and continuous operation has been demonstrated. Minimum pulse lengths of 50 {mu}s have been achieved. Since the generators are easily serviceable, they offer a long lifetime neutron generator for laboratories and commercial systems requiring continuous operation. Several of the generators have been enclosed in radiation shielding/moderator structures designed for customer specifications. These generators have been proven to be useful for prompt gamma neutron activation analysis (PGNAA), neutron activation analysis (NAA) and fast neutron radiography. Thus these generators make excellent fast, epithermal and thermal neutron sources for laboratories and industrial applications that require neutrons with safe operation, small footprint, low cost and small regulatory burden.

  18. Gasdynamic measurements for the LASL intense neutron source

    International Nuclear Information System (INIS)

    Johnston, S.C.

    1978-02-01

    Measurements made on a two-dimensional simulation of the Los Alamos Scientific Laboratory (LASL) Intense Neutron Source (INS) experiment are discussed. The purpose of this work was to characterize the supersonic INS channel flow under conditions of large amounts of energy deposition. Nozzle channel wall pressure measurements, cold flow leakage rates, vacuum channel pressure and Mach number, leakage flow rates with mass addition to and momentum extraction from the main flow, and flow visualization photographs are given. Energy addition up to thirty percent of the theoretical maximum was achieved via mass addition to and momentum extraction from the main channel flow. In this range, both a weak and strong regime for leakage flow were identified. These regimes differed by about twenty percent in leakage flow rates

  19. Design of small ECR ion source for neutron generator

    International Nuclear Information System (INIS)

    Zhou Changgeng; Lou Benchao; Zu Xiulan; Yang Haisu; Xiong Riheng

    2003-01-01

    The principles, structures and characteristics of small ECR (Electron Cyclotron Resonance) ion source used in the neutron generator are introduced. The processes of the design and key technique and innovations are described. (authors)

  20. A single-beam deuteron compact accelerator for neutron generation

    International Nuclear Information System (INIS)

    Araujo, Wagner Leite; Campos, Tarcisio Passos Ribeiro de

    2011-01-01

    Portable neutron generators are devices composed by small size accelerators that produce neutrons through fusion between hydrogen isotopes. These reactions are characterized by appreciable cross section at energies at the tens of keV, which enables device portability. The project baselines follow the same physical and engineering principles of any other particle accelerators. The generator consists of a gas reservoir, apparatus for ion production, few electrodes to accelerate and focus the ion beam, and a metal hydride target where fusion reactions occur. Neutron generator applications include geophysical measurements, indus- trial process control, environmental, research, nation's security and mechanical structure analysis.This article presents a design of a compact accelerator for d-d neutron generators, describing the physical theory applied to the deuteron extraction system, and simulating the ion beam transport in the accelerator. (author)

  1. Elemental analysis using temporal gating of a pulsed neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Mitra, Sudeep

    2018-02-20

    Technologies related to determining elemental composition of a sample that comprises fissile material are described herein. In a general embodiment, a pulsed neutron generator periodically emits bursts of neutrons, and is synchronized with an analyzer circuit. The bursts of neutrons are used to interrogate the sample, and the sample outputs gamma rays based upon the neutrons impacting the sample. A detector outputs pulses based upon the gamma rays impinging upon the material of the detector, and the analyzer circuit assigns the pulses to temporally-based bins based upon the analyzer circuit being synchronized with the pulsed neutron generator. A computing device outputs data that is indicative of elemental composition of the sample based upon the binned pulses.

  2. Development of a compact D-D neutron generator

    Science.gov (United States)

    Huang, Z.-W.; Wang, J.-R.; Wei, Z.; Lu, X.-L.; Ma, Z.-W.; Ran, J.-L.; Zhang, Z.-M.; Yao, Z.-E.; Zhang, Y.

    2018-01-01

    A compact D-D neutron generator was developed at Lanzhou University, China. A duoplasmatron ion source was used to produce a higher-current deuteron beam. The deuteron beam could be accelerated up to 150 keV by a single accelerating gap, and bombarded on a pure molybdenum drive-in target to produce D-D fast neutron. A bias voltage between the target and the extraction-accelerating electrode was produced by a resistance to suppress the secondary electron from the target. The neutron generator has been operated for several hundred hours, and the performances were investigated. The available range of the deuteron beam current was 1.0-4.0 mA. EJ410 scintillator detector system was used to measure the fast neutron yields. D-D neutron yield could reach 2.48×108 n/s under the deuteron beam of 3 mA and 150 keV.

  3. A neutron dynamic therapy with a boron tracedrug UTX-51 using a compact neutron generator.

    Science.gov (United States)

    Hori, Hitoshi; Tada, Ryu; Uto, Yoshihiro; Nakata, Eiji; Morii, Takashi; Masuda, Kai

    2014-08-01

    We are developing a neutron dynamic therapy (NDT) with boron tracedrugs for a new mechanical-clearance treatment of pathotoxic misfolded, aggregated, and self-propagating prion-associated disease proteins. We present a compact neutron generator-based NDT using a boron tracedrug UTX-51. Our NDT is based on the weak thermal neutron-bombarded destructive action of UTX-51 on bovine serum albumin (BSA) using the neutron beams produced from a compact inertial electrostatic confinement fusion (IECF) neutron generator. BSA as an NDT molecular target was subjected to thermal neutron irradiation for eight hours using a compact neutron generator. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis pattern showed no protein band when 2 nmoles of BSA were irradiated with more than 100 nmoles of UTX-51, while BSA was not affected when irradiated without UTX-51. For the first time, we have succeeded in the molecular destruction of a prion-disease model protein, BSA, by NDT with a boron tracedrug, UTX-51, using a compact neutron generator. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  4. RF acceleration of intense laser generated proton bunches

    Energy Technology Data Exchange (ETDEWEB)

    Almomani, Ali

    2012-07-13

    With respect to laser-accelerated beams, the high current capability of the CH-DTL cavity has been investigated. Beam simulations have demonstrated that 10{sup 10} protons per bunch can be accelerated successfully and loss free along the structure. It was shown that, the maximum number of protons per bunch that can be accelerated in the first cavity by exploiting about 1% of the stored field energy is 2.02 x 10{sup 11} protons. One further aspect is the total number of protons arriving at the linac entrance. One main aspect of an rf postacceleration experiment is the rf operation stability under these beam load conditions. Detailed simulations from the target along the solenoid and down to the linac entrance were presented, applying adapted software. Special care was taken on the time steps, especially close to the target, and on the collective phenomena between electron and proton distributions. The effect of comoving electrons on the beam dynamics has been investigated in detail. A CH-linac with high space charge limit and large transverse and longitudinal acceptance was designed to accept a maximum fraction of the laser generated proton bursts. Due to well-known transformations of the injected beam emittances along the CH-cavity, it is aimed to derive parameters of the laser generated beam by measuring the beam properties behind of the CH-cavity. With respect to the linac development it is intended to realize the first cavity of the proposed CH-DTL and to demonstrate the acceleration of a laser generated proton bunch with the LIGHT project. The first cavity consists of 7 gaps within a total length of about 668 mm. It is operated at 325 MHz and has an effective accelerating field gradient of about 12.6 MV/m. The study on the surface electric field for this cavity shows, that maximum surface fields of about 94 MV/m and 88 MV/m on the third and sixth drift tubes are reachable, respectively.

  5. Monte Carlo computation of Bremsstrahlung intensity and energy spectrum from a 15 MV linear electron accelerator tungsten target to optimise LINAC head shielding

    International Nuclear Information System (INIS)

    Biju, K.; Sharma, Amiya; Yadav, R.K.; Kannan, R.; Bhatt, B.C.

    2003-01-01

    The knowledge of exact photon intensity and energy distributions from the target of an electron target is necessary while designing the shielding for the accelerator head from radiation safety point of view. The computations were carried out for the intensity and energy distribution of photon spectrum from a 0.4 cm thick tungsten target in different angular directions for 15 MeV electrons using a validated Monte Carlo code MCNP4A. Similar results were computed for 30 MeV electrons and found agreeing with the data available in literature. These graphs and the TVT values in lead help to suggest an optimum shielding thickness for 15 MV Linac head. (author)

  6. Proceedings of the 14. International Symposium on the Interaction of Fast Neutrons with Nuclei - Neutron Generators and Application - organized by the Technical University of Dresden

    International Nuclear Information System (INIS)

    Seeliger, D.; Jahn, U.

    1985-07-01

    The symposium was devoted to current problems of intense fast neutron sources, especially 14 MeV DT-neutron generators, and their broad spectrum of application in nuclear physics. 56 participants from 12 countries and the IAEA demonstrate the high interest on this selected topics. The submitted contributions can be divided into two general parts. The first one gives a review about the different possibilities of the technical and technological solution in development, the present status of operation and also the problems connected with the use of intense neutron sources. Various experimental arrangements for neutron spectroscopy, determination of nuclear data and theoretical aspects are the content of the second part. The participation in this meeting of designer and operators on the one hand and users of neutron sources on the other hand was a good choice and stimulated productive discussions during the conference. (author)

  7. Utilization of low voltage D-T neutron generators in neutron physics studies

    International Nuclear Information System (INIS)

    Singkarat, S.

    1995-01-01

    In a small nuclear laboratory of a developing country a low voltage D-T neutron generator can be a very useful scientific apparatus. Such machines have been used successfully for more than 40 years in teaching and scientific research. The original continuous mode 150-kV D-T neutron generator has been modified to have also a capability of producing 2-ns pulsed neutrons. Together with a carefully designed 10 m long flight path collimator and shielding of a 25 cm diameter · 10 cm thick BC-501 neutron detector, the pulsing system was successfully used for measuring the double differential cross-section (DDX) of natural iron for 14.1-MeV neutron from the angle of 30 deg to 150 deg in 10 deg steps. In order to extend the utility of the generator, two methods for converting the almost monoenergetic 14-MeV neutrons to monoenergetic neutrons of lower energy were proposed and tested. Both designs used the neutron-proton interaction at a circular surface-of-revolution made of hydrocarbon materials. The first design is for a pulsed neutron generator and the second design is for an ordinary continuous mode generator. The latter method was successfully used to measure the scintillation light output of a 1.4 cm diameter spherical NE-213 scintillation detector. The neutron generator has also been used in the continuous search for improved neutron detection techniques. There is a proposal, based on Monte Carlo calculations, of using a scintillation fiber for a fast neutron spectrometer. Due to the slender shape of the fiber, the pattern of produced light gives a peak in the pulse height spectrum instead of the well-known rectangular-like distribution, when the fiber is bombarded end-on by a beam of 14-MeV neutrons. Experimental investigations were undertaken. Detailed investigations on the light transportation property of a short fiber were performed. The predicted peak has not yet been found but the fiber detector may be developed as a directional discrimination fast neutron

  8. Pulsed White Spectrum Neutron Generator for Explosive Detection

    International Nuclear Information System (INIS)

    King, Michael J.; Miller, Gill T.; Reijonen, Jani; Ji, Qing; Andresen, Nord; Gicquel, Frederic; Kavlas, Taneli; Leung, Ka-Ngo; Kwan, Joe

    2008-01-01

    Successful explosive material detection in luggage and similar sized containers is a critical issue in securing the safety of all airline passengers. Tensor Technology Inc. has recently developed a methodology that will detect explosive compounds with pulsed fast neutron transmission spectroscopy. In this scheme, tritium beams will be used to generate neutrons with a broad energy spectrum as governed by the T(t,2n)4He fission reaction that produces 0-9 MeV neutrons. Lawrence Berkeley National Laboratory (LBNL), in collaboration with Tensor Technology Inc., has designed and fabricated a pulsed white-spectrum neutron source for this application. The specifications of the neutron source are demanding and stringent due to the requirements of high yield and fast pulsing neutron emission, and sealed tube, tritium operation. In a unique co-axial geometry, the ion source uses ten parallel rf induction antennas to externally couple power into a toroidal discharge chamber. There are 20 ion beam extraction slits and 3 concentric electrode rings to shape and accelerate the ion beam into a titanium cone target. Fast neutron pulses are created by using a set of parallel-plate deflectors switching between +-1500 volts and deflecting the ion beams across a narrow slit. The generator is expected to achieve 5 ns neutron pulses at tritium ion beam energies between 80-120 kV. First experiments demonstrated ion source operation and successful beam pulsing

  9. Linac4 Technical Design Report

    CERN Document Server

    Arnaudon, L; Baylac, M; Bellodi, G; Body, Y; Borburgh, J; Bourquin, P; Broere, J; Brunner, O; Bruno, L; Carli, C; Caspers, Friedhelm; Cousineau, S M; Cuvet, Y; De Almeida Martins, C; Dobers, T; Fowler, T; Garoby, R; Gerigk, F; Goddard, B; Hanke, K; Hori, M; Jones, M; Kahle, K; Kalbreier, Willi; Kroyer, T; Küchler, D; Lombardi, A M; López-Hernandez, L A; Magistris, M; Martini, M; Maury, S; Page, E; Paoluzzi, M; Pasini, M; Raich, U; Rossi, C; Royer, J P; Sargsyan, E; Serrano, J; Scrivens, R; Silari, M; Timmins, M; Venturini-Delsolaro, W; Vretenar, M; Wegner, R; Weterings, W; Zickler, T

    2006-01-01

    Linac4 is an H- linear accelerator, intended to replace Linac2 as injector to the PS Booster (PSB). By delivering to the PSB a beam at 160 MeV energy, Linac4 will provide the conditions to double the brightness and intensity of the beam from the PSB, thus removing the first bottleneck towards higher brightness for the LHC and simplifying operation. Moreover, this new linac constitutes an essential component of any of the envisaged LHC upgrade scenarios and could open the way to future extensions of the CERN accelerator complex towards higher performance. This Technical Design Report presents a detailed technical overview of the Linac4 design as it stands at end 2006.

  10. Neutron excess generation by fusion neutron source for self-consistency of nuclear energy system

    International Nuclear Information System (INIS)

    Saito, Masaki; Artisyuk, V.; Chmelev, A.

    1999-01-01

    The present day fission energy technology faces with the problem of transmutation of dangerous radionuclides that requires neutron excess generation. Nuclear energy system based on fission reactors needs fuel breeding and, therefore, suffers from lack of neutron excess to apply large-scale transmutation option including elimination of fission products. Fusion neutron source (FNS) was proposed to improve neutron balance in the nuclear energy system. Energy associated with the performance of FNS should be small enough to keep the position of neutron excess generator, thus, leaving the role of dominant energy producers to fission reactors. The present paper deals with development of general methodology to estimate the effect of neutron excess generation by FNS on the performance of nuclear energy system as a whole. Multiplication of fusion neutrons in both non-fissionable and fissionable multipliers was considered. Based on the present methodology it was concluded that neutron self-consistency with respect to fuel breeding and transmutation of fission products can be attained with small fraction of energy associated with innovated fusion facilities. (author)

  11. Characterization of a deuterium-deuterium plasma fusion neutron generator

    Science.gov (United States)

    Lang, R. F.; Pienaar, J.; Hogenbirk, E.; Masson, D.; Nolte, R.; Zimbal, A.; Röttger, S.; Benabderrahmane, M. L.; Bruno, G.

    2018-01-01

    We characterize the neutron output of a deuterium-deuterium plasma fusion neutron generator, model 35-DD-W-S, manufactured by NSD/Gradel-Fusion. The measured energy spectrum is found to be dominated by neutron peaks at 2.2 MeV and 2.7 MeV. A detailed GEANT4 simulation accurately reproduces the measured energy spectrum and confirms our understanding of the fusion process in this generator. Additionally, a contribution of 14 . 1 MeV neutrons from deuterium-tritium fusion is found at a level of 3 . 5%, from tritium produced in previous deuterium-deuterium reactions. We have measured both the absolute neutron flux as well as its relative variation on the operational parameters of the generator. We find the flux to be proportional to voltage V 3 . 32 ± 0 . 14 and current I 0 . 97 ± 0 . 01. Further, we have measured the angular dependence of the neutron emission with respect to the polar angle. We conclude that it is well described by isotropic production of neutrons within the cathode field cage.

  12. Kinetic description of electron-proton instability in high-intensity proton linacs and storage rings based on the Vlasov-Maxwell equations

    Directory of Open Access Journals (Sweden)

    Ronald C. Davidson

    1999-05-01

    electrons is negligibly small. We introduce the ion plasma frequency squared defined by ω[over ^]_{pb}^{2}=4πn[over ^]_{b}Z_{b}^{2}e^{2}/γ_{b}m_{b}, and the fractional charge neutralization defined by f=n[over ^]_{e}/Z_{b}n[over ^]_{b}, where n[over ^]_{b} and n[over ^]_{e} are the characteristic ion and electron densities. The equilibrium and stability analysis is carried out for arbitrary normalized beam intensity ω[over ^]_{pb}^{2}/ω_{βb}^{0^{2}}, and arbitrary fractional charge neutralization f, consistent with radial confinement of the beam particles. For the moderately high beam intensities envisioned in the proton linacs and storage rings for the Accelerator for Production of Tritium and the Spallation Neutron Source, the normalized beam intensity is typically ω[over ^]_{pb}^{2}/ω_{βb}^{0^{2}}≲ 0.1. For heavy ion fusion applications, however, the transverse beam emittance is very small, and the space-charge-dominated beam intensity is much larger, with ω[over ^]_{pb}^{2}/ω_{βb}^{0^{2}}≲ 2γ_{b}^{2}. The stability analysis shows that the instability growth rate Imω increases with increasing normalized beam intensity ω[over ^]_{pb}^{2}/ω_{βb}^{0^{2}} and increasing fractional charge neutralization f. In addition, the instability is strongest (largest growth rate for perturbations with azimuthal mode number ℓ=1, corresponding to a simple (dipole transverse displacement of the beam ions and the background electrons. For the case of overlapping step-function density profiles for the beam ions and background electrons, corresponding to monoenergetic ions and electrons, a key result is that there is no threshold in beam intensity ω[over ^]_{pb}^{2}/ω_{βb}^{0^{2}} or fractional charge neutralization f for the onset of instability. Finally, for the case of continuously varying density profiles with parabolic profile shape, a semiquantitative estimate is made of the effects of the corresponding spread in (depressed betatron frequency on stability

  13. Means and method for controlling the neutron output of a neutron generator tube

    International Nuclear Information System (INIS)

    Langford, O.M.; Peelman, H.E.

    1978-01-01

    Means and method are described for energizing and regulating a neutron generator tube having a target, an ion source and a replenisher. It providing a negative high voltage to the target and monitoring the target current. A constant current from a constant current source is divided into a shunt current and a replenisher current in accordence with the target current. The replenisher current is applied to the replenisher in a neutron generator tube so as to control the neutron output in accordance with the target current

  14. Means and method for controlling the neutron output of a neutron generator tube

    International Nuclear Information System (INIS)

    1977-01-01

    A means and method for energizing and regulating a neutron generator tube is described. It has a target, an ion source and a replenisher. A negative high voltage is applied to the target and the target current monitored. A constant current from a constant current source is divided into a shunt current and a replenisher current in accordance with the target current. The replenisher current is applied to the replenisher in a neutron generator tube so as to control the neutron output in accordance with the target current. (C.F.)

  15. High field electron linacs

    International Nuclear Information System (INIS)

    Le Duff, J.

    1985-12-01

    High field electron linacs are considered as potential candidates to provide very high energies beyond LEP. Since almost twenty years not much improvement has been made on linac technologies as they have been mostly kept at low and medium energies to be used as injectors for storage rings. Today, both their efficiency and their performances are being reconsidered, and for instance the pulse compression sheme developed at SLAC and introduced to upgrade the energy of that linac is a first step towards a new generation of linear accelerators. However this is not enough in terms of power consumption and more development is needed to improve both the efficiency of accelerating structures and the performances of RF power sources

  16. Modification of Prototype D-D Neutron Generator

    International Nuclear Information System (INIS)

    Kim, In Jung; Kim, Suk Kwon; Park, Chang Su; Jung, Nam Suk; Jung, Hwa Dong; Park, Ji Young; Hwang, Yong Seok; Choi, H. D.

    2005-01-01

    The prototype D-D neutron generator was modified in order to enhance the neutron yield. The distance from ion source to target was reduced to increase the ion beam current at target position. Thick Ti target was replaced by thin Ti target which was vacuum-deposited on Cu substrate in order to enhance the target cooling. Performance of the modified device was tested

  17. On generating neutron transport tables with the NJOY system

    International Nuclear Information System (INIS)

    Caldeira, Alexandre D.; Claro, Luiz H.

    2013-01-01

    Incorrect values for the product of the average number of neutrons released per fission and the fission microscopic cross-section were detected in several energy groups of a neutron transport table generated with the most updated version of the NJOY system. It was verified that the problem persists when older versions of this system are utilized. Although this problem exists for, at least, ten years, it is still an open question. (author)

  18. Neutron generator for BNCT based on high current ECR ion source with gyrotron plasma heating.

    Science.gov (United States)

    Skalyga, V; Izotov, I; Golubev, S; Razin, S; Sidorov, A; Maslennikova, A; Volovecky, A; Kalvas, T; Koivisto, H; Tarvainen, O

    2015-12-01

    BNCT development nowadays is constrained by a progress in neutron sources design. Creation of a cheap and compact intense neutron source would significantly simplify trial treatments avoiding use of expensive and complicated nuclear reactors and accelerators. D-D or D-T neutron generator is one of alternative types of such sources for. A so-called high current quasi-gasdynamic ECR ion source with plasma heating by millimeter wave gyrotron radiation is suggested to be used in a scheme of D-D neutron generator in the present work. Ion source of that type was developed in the Institute of Applied Physics of Russian Academy of Sciences (Nizhny Novgorod, Russia). It can produce deuteron ion beams with current density up to 700-800 mA/cm(2). Generation of the neutron flux with density at the level of 7-8·10(10) s(-1) cm(-2) at the target surface could be obtained in case of TiD2 target bombardment with deuteron beam accelerated to 100 keV. Estimations show that it is enough for formation of epithermal neutron flux with density higher than 10(9) s(-1) cm(-2) suitable for BNCT. Important advantage of described approach is absence of Tritium in the scheme. First experiments performed in pulsed regime with 300 mA, 45 kV deuteron beam directed to D2O target demonstrated 10(9) s(-1) neutron flux. This value corresponds to theoretical estimations and proofs prospects of neutron generator development based on high current quasi-gasdynamic ECR ion source. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Status of the SNS superconducting linac and future plan

    International Nuclear Information System (INIS)

    Kim, Sang-Ho

    2008-01-01

    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 generates neutrons by the spallation reaction with the accelerated short (about 700 ns) sub-bunches of protons, 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 and has been operating with beam for almost two years. As the first operational pulsed superconducting linac, many of the aspects of its performance were unknown and unpredictable. A lot of experiences and data have been gathered on the pulsed behavior of cavities and cryomodules at various repetition rates and at various temperatures during the commissioning of its components and beam operations. This experience is of great value in determining future optimizations of SNS as well in guiding in the design and operation of future pulsed superconducting linacs. The testing of the superconducting cavities, the operating experience with beam, the performance of the superconducting linac and the future plans will be presented.

  20. Intensity Modulated Neutron Radiotherapy for the Treatment of Adenocarcinoma of the Prostate

    International Nuclear Information System (INIS)

    Santanam, Lakshmi; He, Tony; Yudelev, Mark; Forman, Jeffrey D.; Orton, Colin G.; Heuvel, Frank van den; Maughan, Richard L.; Burmeister, Jay

    2007-01-01

    Purpose: This study investigates the enhanced conformality of neutron dose distributions obtainable through the application of intensity modulated neutron radiotherapy (IMNRT) to the treatment of prostate adenocarcinoma. Methods and Materials: An in-house algorithm was used to optimize individual segments for IMNRT generated using an organ-at-risk (OAR) avoidance approach. A number of beam orientation schemes were investigated in an attempt to approach an optimum solution. The IMNRT plans were created retrospectively for 5 patients previously treated for prostate adenocarcinoma using fast neutron therapy (FNT), and a comparison of these plans is presented. Dose distributions and dose-volume histograms (DVHs) were analyzed and plans were evaluated based on percentage volumes of rectum and bladder receiving 95%, 80%, and 50% (V 95 , V 80 , V 50 ) of the prescription dose, and on V 60 for both the femoral heads and GM muscle group. Results: Plans were normalized such that the IMNRT DVHs for prostate and seminal vesicles were nearly identical to those for conventional FNT plans. Use of IMNRT provided reductions in rectum V 95 and V 80 of 10% (2-27%) and 13% (5-28%), respectively, and reductions in bladder V 95 and V 80 of 12% (3-26%) and 4% (7-10%), respectively. The average decrease in V 60 for the femoral heads was 4.5% (1-18%), with no significant change in V 60 for the GM muscle group. Conclusions: This study provides the first analysis of the application of intensity modulation to neutron radiotherapy. The IMNRT technique provides a substantial reduction in normal tissue dose in the treatment of prostate cancer. This reduction should result in a significant clinical advantage for this and other treatment sites

  1. Study and optimization of a LINAC drift tube for high intensity proton acceleration; Etude et optimisation d'un LINAC a tubes de glissement pour acceleration de forts courants de protons en continu

    Energy Technology Data Exchange (ETDEWEB)

    Bernaudin, P.E

    2002-09-01

    High intensity proton accelerators lead to specific problems related to the need to limit beam losses. The problem is more acute in the low energy part (up to 20 MeV) where the beam transport is the most difficult. The drift tube linac (DTL) remains the reference structure for energies of a few MeV to a few dozens MeV despite the arising of some new cavity types. This thesis purpose is to design such a DTL for a high intensity proton accelerator. Until now, no such continuous wave cavity has ever been operated. To ensure the viability of such an accelerator, a short four cells prototype is designed, built and tested under nominal RF conditions. This prototype is fully representative of a complete machine except for its length. The design complexity comes from the combination of RF electromagnetism, thermal exchanges, mechanics, ultra-vacuum engineering and manufacturing constraints. More specifically, the electromagnets alignment is a primary factor, and reliability, despite being usually of secondary importance in particles accelerator science, is here a major concern considering potential industrial applications of this machine. The prototype design includes the cavity itself, but also quadrupole electromagnets whose feasibility is a limiting factor, considering the very small space available to them. Two different magnet types and associated drift tubes are studied and manufactured, to be tested in the prototype cavity. The experimental part is focused on mechanical and thermal aspects. The electromagnetic properties of the cavity are also checked. As a conclusion of this thesis, technical and conceptual improvements as suggested by the manufacturing and experimental phases are presented, to be implemented in a complete cavity. (author)

  2. Linacs for medical and industrial applications

    International Nuclear Information System (INIS)

    Hamm, R.W.

    1986-01-01

    Linear accelerators for medical and industrial applications have become an important commercial business. Microwave electron linacs for cancer radiation therapy and high-energy industrial radiography form the bulk of this market, but these, as well as induction linacs, are now being offered for radiation processing applications such as sterilization of disposable medical products, food preservation and material modifications. The radio frequency quadrupole (RFQ) linac has now made the ion linac also practical for commercial applications in medicine and industry, including radiation therapy, isotope production, neutron production, materials modification, and energy transfer processes. Ion linacs for several of these applications will soon be commercially available. The market for both ion and electron linacs is expected to significantly grow in several exciting and important areas

  3. Online monitoring of fast neutron (DT/DD) at Purnima neutron generator

    International Nuclear Information System (INIS)

    Bishnoi, S.; Patel, T.; Shukla, M.; Adhikari, P.S.; Sinha, A.

    2012-01-01

    A neutron generator (NG) at Purnima Labs, BARC has been developed for DT accelerator driven zero power subcritical (ADSS) system. Subcritical core of ADSS will be coupled to the NG for benchmarking experiments. Kinetic parameters of ADSS such as K-source, flux, power etc depends on this external neutron source strength injected to the core. However the neutron emission rate of NG does not remain stable throughout its operation. In view of this a reliable, precise and online monitoring of NG's neutron emission rate is required. An online neutron monitoring system based on associated particle method has been designed, developed and installed at NG. The monitoring unit consists of an ion implanted planar silicon detector, placed inside the drift tube of NG at an angle with respect to D + beam direction. A series of experiments were carried out with increasing neutron yield to optimize the position of detector such that it has sufficient counting statistics and minimum pileup. A complementary calibration procedure for validating these results based on activation technique was also carried out with standard Cu foil. The reaction rate monitored with online monitor and foil activation technique were compared, their variations with the predicted (theoretical) results were within 16%. This paper deals with the development and performance of online neutron monitoring system for DT and DD neutrons

  4. Photon and photoneutron spectra produced in radiotherapy Linacs

    International Nuclear Information System (INIS)

    Vega C, H. R.; Martinez O, S. A.; Benites R, J. L.; Lallena, A. M.

    2011-10-01

    A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10 -6 and 1 MeV. Neutron and Bremsstrahlung spectra show the same features regardless of the linac voltage. The amount of photons and neutrons produced by the 15 MV linac is smaller than that found for the 18 MV linac. As expected, Bremsstrahlung spectra ends according to the voltage used to accelerate the electrons. (Author)

  5. Photon and photoneutron spectra produced in radiotherapy Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Martinez O, S. A. [Universidad Pedagogica y Tecnologica de Colombia, Grupo de Fisica Nuclear Aplicada y Simulacion, Av. Central del Norte Km. 1, Via Paipa Tunja, Boyaca (Colombia); Benites R, J. L. [Universidad Autonoma de Nayarit, Postgrado CBAP, Carretera Tepic Compostela Km. 9, Xalisco, Nayarit (Mexico); Lallena, A. M., E-mail: fermineutron@yahoo.com [Universida de Granada, Departamento de Fisica Atomica, Molecular y Nuclear, E-18071 Granada (Spain)

    2011-10-15

    A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10{sup -6} and 1 MeV. Neutron and Bremsstrahlung spectra show the same features regardless of the linac voltage. The amount of photons and neutrons produced by the 15 MV linac is smaller than that found for the 18 MV linac. As expected, Bremsstrahlung spectra ends according to the voltage used to accelerate the electrons. (Author)

  6. Spatial distribution of neutron flux for the A-711 neutron generator

    International Nuclear Information System (INIS)

    Essiet, A. E.; Owolabi, S. A.; Adesanmi, C. A.; Balogun, F. A.

    1996-01-01

    The spatial distribution of neutron flux for the Kaman sciences A-711 neutron generator recently installed at the Centre for Energy Research and Development (CERD), Ile-Ife Nigeria has been determined. At an operational tube current of 2.0 mA and high voltage power supply (HVPS) of 158 kV, the neutron flux increases from 1.608 ± 0.021*10 8 n/cm 2 s at the top of the irradiated plastic vial to 2.640 ± 0.022*10 8 n/cm 2 s at the centre, and then decreases to 1.943 ± 0.02* 8 n/cm 2 s at the bottom. The flux density is strongly dependent on the diameter of deuteron at the tritium target, and within this range a source strength of 10 8 n/s has been measured for the A-711 neutron generator

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

    Science.gov (United States)

    Gaganov, V. V.

    2017-12-01

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

  8. Means and method for controlling the neutron output of a neutron generator tube

    International Nuclear Information System (INIS)

    1980-01-01

    A specification is given for an energizing and regulating circuit for a gas filled neutron generator tube consisting of a target, an ion source and a replenisher, the circuit consisting of a power supply to provide a negative high voltage to the target and a target current corresponding to the neutron output of the tube, a constant current source, and control means connected to the power supply and to the constant current source, the control means being responsive to the target current to provide a portion of the constant current to the replenisher substantially to regulate the neutron output of the tube. (author)

  9. Neutron lifetime and generation time by KENO IV

    International Nuclear Information System (INIS)

    Hayashi, Masatoshi

    1991-01-01

    It is believed that Monte Carlo method is suitable to the calculation of neutron lifetime and generation time with reference to the life cycle viewpoint. This paper illustrates that those times obtained by Monte Carlo method are quite different from the results by perturbation method. The neutron lifetime and the generation time for bare and reflected reactors were investigated by the Monte Carlo program, KENO IV. the Monte Carlo procedure is based on tracking and recording the life history of neutrons in a realistic fashion in a fissionable system with minimum nuclear and geometric approximations. The KENO IV provides the multiplication factor, neutron lifetime and generation time simultaneously. The thermal spherical reactors for both bare and reflected reactors were studied using the KENO IV. The reflected reactor is surrounded with 30 cm thick light water. The atomic densities in the regions and the calculated results of the multiplication factor, neutron lifetime and generation time are given. The different definitions of these times between the Monte Carlo method and perturbation theory caused the difference of the results. (K.I.)

  10. A neutron beam facility for radioactive ion beams and other applications

    Science.gov (United States)

    Tecchio, L. B.

    1999-06-01

    In the framework of the Italian participation in the project of a high intensity proton facility for the energy amplifier and nuclear waste transmutations, LNL is involved in the design and construction of same prototypes of the injection system of the 1 GeV linac that consists of a RFQ (5 MeV, 30 mA) followed by a 100 MeV linac. This program has already been supported financially and the work is in progress. In this context LNL has proposed a project for the construction of a second generation facility for the production of radioactive ion beams (RIBs) by means of the ISOL method. The final goal is the production of neutron rich RIBs with masses ranging from 30 to 150 by using primary beams of protons, deuterons and light ions with energy of 100 MeV and 100 kW power. This project is expected to be developed in about 10 years from new and intermediate milestones and experiments are foreseen and under consideration for the next INFN five year plan (1999-2003). During that period the construction of a proton/deuteron accelerator of 10 MeV energy and 10 mA current, consisting of a RFQ (5 MeV, 30 mA) and a linac (10 MeV, 10 mA), and of a neutron area dedicated to the RIBs production and to the neutron physics, is proposed. Some remarks on the production methods will be presented. The possibility of producing radioisotopes by means of the fission induced by neutrons will be investigated and the methods of production of neutrons will be discussed. Besides the RIBs production, neutron beams for the BNCT applications and neutron physics are also planned.

  11. Beam halo in high-intensity beams

    International Nuclear Information System (INIS)

    Wangler, T.P.

    1993-01-01

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. The author describes what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. Initial results are presented from a study of beam entropy for an intense space-charge dominated beam

  12. The shielding of a 14 MeV neutron generator

    International Nuclear Information System (INIS)

    Brighton, D.R.

    1976-10-01

    The concrete masonry shield for a 14 MeV neutron generator was designed using data supplied by the manufacturer. Subsequent radiation surveys outside the shield showed doses higher than expected. Calculations indicated the sensitivity of dose transmission factors to concrete composition. The observed dose transmission factor agreed with that of Broerse but not with that of Hacke and Prudhomme. Measurements and calculations delineated the contribution that neutrons, scattered from the upper wall that supports the laboratory roof, made to the dose in adjoining areas. In redesigning the shield a compromise was made between additional cost and restrictions on the generator's duty cycle, which is automatically controlled to ensure personnel safety. (Author)

  13. Sustaining knowledge in the neutron generator community and benchmarking study.

    Energy Technology Data Exchange (ETDEWEB)

    Barrentine, Tameka C.; Kennedy, Bryan C.; Saba, Anthony W.; Turgeon, Jennifer L.; Schneider, Julia Teresa; Stubblefield, William Anthony; Baldonado, Esther

    2008-03-01

    In 2004, the Responsive Neutron Generator Product Deployment department embarked upon a partnership with the Systems Engineering and Analysis knowledge management (KM) team to develop knowledge management systems for the neutron generator (NG) community. This partnership continues today. The most recent challenge was to improve the current KM system (KMS) development approach by identifying a process that will allow staff members to capture knowledge as they learn it. This 'as-you-go' approach will lead to a sustainable KM process for the NG community. This paper presents a historical overview of NG KMSs, as well as research conducted to move toward sustainable KM.

  14. Beam splitting to improve target life in neutron generators

    International Nuclear Information System (INIS)

    Farrell, J.P.

    1976-01-01

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

  15. ITEP Subcritical Neutron Generator driven by charged particle accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Shvedov, O.V.; Chuvilo, I.V.; Vasiliev, V.V. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation)] [and others

    1995-10-01

    A research facility prototype including a combination of a linear accelerator, a neutron generating target, a nuclear safety ensuring and means of its attainment for Subcritical Neutron Generator are considered. The scheme of the multiplying is shown. The assembly will be mounted in the body of the partly dismantled ITEP HWR. Requirements for subcritical assembly are worked out and their feasibility within the framework of the heavy-water blanket is shown. The facility`s application as a full-scale model of more powerful installations of this kind and for fundamental experimental research has been investigated.

  16. A Dosimetry Study of Deuterium-Deuterium Neutron Generator-based In Vivo Neutron Activation Analysis.

    Science.gov (United States)

    Sowers, Daniel; Liu, Yingzi; Mostafaei, Farshad; Blake, Scott; Nie, Linda H

    2015-12-01

    A neutron irradiation cavity for in vivo neutron activation analysis (IVNAA) to detect manganese, aluminum, and other potentially toxic elements in human hand bone has been designed and its dosimetric specifications measured. The neutron source is a customized deuterium-deuterium neutron generator that produces neutrons at 2.45 MeV by the fusion reaction 2H(d, n)3He at a calculated flux of 7 × 10(8) ± 30% s(-1). A moderator/reflector/shielding [5 cm high density polyethylene (HDPE), 5.3 cm graphite and 5.7 cm borated (HDPE)] assembly has been designed and built to maximize the thermal neutron flux inside the hand irradiation cavity and to reduce the extremity dose and effective dose to the human subject. Lead sheets are used to attenuate bremsstrahlung x rays and activation gammas. A Monte Carlo simulation (MCNP6) was used to model the system and calculate extremity dose. The extremity dose was measured with neutron and photon sensitive film badges and Fuji electronic pocket dosimeters (EPD). The neutron ambient dose outside the shielding was measured by Fuji NSN3, and the photon dose was measured by a Bicron MicroREM scintillator. Neutron extremity dose was calculated to be 32.3 mSv using MCNP6 simulations given a 10-min IVNAA measurement of manganese. Measurements by EPD and film badge indicate hand dose to be 31.7 ± 0.8 mSv for neutrons and 4.2 ± 0.2 mSv for photons for 10 min; whole body effective dose was calculated conservatively to be 0.052 mSv. Experimental values closely match values obtained from MCNP6 simulations. These are acceptable doses to apply the technology for a manganese toxicity study in a human population.

  17. BNCT with linac, feasibility study

    International Nuclear Information System (INIS)

    Alfuraih, A.; Ma, A.; Spyrou, N.M.; Awotwi-Pratt, Joseph

    2006-01-01

    High energy photon beams from Medical Linear Accelerators (linacs) which are used in radiotherapy produce undesirable neutrons, beside the clinically useful electron and photon beams. Neutrons are produced from the photonuclear reaction (γ,n) of high energy photons with high Z-materials which compose the accelerator head. In this paper the possible use of these undesirable neutrons for BNCT is investigated, making use of high energy linacs already installed in hospitals, primarily for high energy electron and photon therapy and applying them in the context of BNCT. The photoneutron components emitted by the accelerator is the source for Monte Carlo simulations of the interactions that take place within the head of a voxel-based phantom. The neutron flux across the phantom head is calculated using different moderator arrangements and different techniques in the aim of increasing the thermal neutron flux at the targeted site. Also, we shall test different configurations of the linac head to maximize the exposure of high-Z materials to the photon beam, including the removal of the flattening filter, so as to boost the photoneutron production in the linac head. Experimental work will be conducted in hospitals to validate the Monte Carlo simulations. To make use of linacs for BNCT will be advantageous in the sense that the setting in a hospital department is much more acceptable by the public than a reactor installation. This will mean less complications regarding patient positioning and movement with respect to the beams, additional patient transportation and management will be more cost effective. (author)

  18. High-fidelity MCNP modeling of a D-T neutron generator for active interrogation of special nuclear material

    International Nuclear Information System (INIS)

    Katalenich, Jeff; Flaska, Marek; Pozzi, Sara A.; Hartman, Michael R.

    2011-01-01

    Fast and robust methods for interrogation of special nuclear material (SNM) are of interest to many agencies and institutions in the United States. It is well known that passive interrogation methods are typically sufficient for plutonium identification because of a relatively high neutron production rate from 240 Pu . On the other hand, identification of shielded uranium requires active methods using neutron or photon sources . Deuterium-deuterium (2.45 MeV) and deuterium-tritium (14.1 MeV) neutron-generator sources have been previously tested and proven to be relatively reliable instruments for active interrogation of nuclear materials . In addition, the newest generators of this type are small enough for applications requiring portable interrogation systems. Active interrogation techniques using high-energy neutrons are being investigated as a method to detect hidden SNM in shielded containers . Due to the thickness of some containers, penetrating radiation such as high-energy neutrons can provide a potential means of probing shielded SNM. In an effort to develop the capability to assess the signal seen from various forms of shielded nuclear materials, University of Michigan Neutron Science Laboratory's D-T neutron generator and its shielding were accurately modeled in MCNP. The generator, while operating at nominal power, produces approximately 1x10 10 neutrons/s, a source intensity which requires a large amount of shielding to minimize the dose rates around the generator. For this reason, the existing shielding completely encompasses the generator and does not include beam ports. Therefore, several MCNP simulations were performed to estimate the yield of uncollided 14.1-MeV neutrons from the generator for active interrogation experiments. Beam port diameters of 5, 10, 15, 20, and 25 cm were modeled to assess the resulting neutron fluxes. The neutron flux outside the beam ports was estimated to be approximately 2x10 4 n/cm 2 s.

  19. Multi detector input and function generator for polarized neutron experiments

    International Nuclear Information System (INIS)

    De Blois, J.; Beunes, A.J.H.; Ende, P. v.d.; Osterholt, E.A.; Rekveldt, M.T.; Schipper, M.N.; Velthuis, S.G.E. te

    1998-01-01

    In this paper a VME module is described for static or stroboscopic measurements with a neutron scattering instrument, consisting essentially of a series of up to 64 3 He neutron detectors around a sample environment. Each detector is provided with an amplifier and a discriminator to separate the neutrons from noise. To reduce the wiring, the discriminator outputs are connected to the module by coding boxes. Two 16-inputs to one-output coding boxes generate serial output codes on a fiber optic connection. This basically fast connection reduces the dead time introduced by the coding, and the influence of environmental noise. With stroboscopic measurements a periodic function is used to affect the sample surrounded by a field coil. Each detected neutron is labeled with a data label containing the detector number and the time of detection with respect to a time reference. The data time base can be programmed on a linear or a nonlinear scale. An external source or an attribute of the periodic function may generate the time reference pulse. A 12-bit DAC connected to the output of an 8 K, 16-bits memory, where the pattern of the current has been stored before, generates the function. The function memory is scanned by the programmable function time base. Attributes are set by the four remaining bits of the memory. One separate detector input connects a monitor detector in the neutron beam with a 32-bit counter/timer that provides measuring on a preset count, preset time or preset frame. (orig.)

  20. Intense electromagnetic outbursts from collapsing hypermassive neutron stars

    Science.gov (United States)

    Lehner, Luis; Palenzuela, Carlos; Liebling, Steven L.; Thompson, Christopher; Hanna, Chad

    2012-11-01

    We study the gravitational collapse of a magnetized neutron star using a novel numerical approach able to capture both the dynamics of the star and the behavior of the surrounding plasma. In this approach, a fully general relativistic magnetohydrodynamics implementation models the collapse of the star and provides appropriate boundary conditions to a force-free model which describes the stellar exterior. We validate this strategy by comparing with known results for the rotating monopole and aligned rotator solutions and then apply it to study both rotating and nonrotating stellar collapse scenarios and contrast the behavior with what is obtained when employing the electrovacuum approximation outside the star. The nonrotating electrovacuum collapse is shown to agree qualitatively with a Newtonian model of the electromagnetic field outside a collapsing star. We illustrate and discuss a fundamental difference between the force-free and electrovacuum solutions, involving the appearance of large zones of electric-dominated field in the vacuum case. This provides a clear demonstration of how dissipative singularities appear generically in the nonlinear time evolution of force-free fluids. In both the rotating and nonrotating cases, our simulations indicate that the collapse induces a strong electromagnetic transient, which leaves behind an uncharged, unmagnetized Kerr black hole. In the case of submillisecond rotation, the magnetic field experiences strong winding, and the transient carries much more energy. This result has important implications for models of gamma-ray bursts. Even when the neutron star is surrounded by an accretion torus (as in binary merger and collapsar scenarios), a magnetosphere may emerge through a dynamo process operating in a surface shear layer. When this rapidly rotating magnetar collapses to a black hole, the electromagnetic energy released can compete with the later output in a Blandford-Znajek jet. Much less electromagnetic energy is

  1. Neutron dosimetry in organs of an adult human phantom using linacs with multileaf collimator in radiotherapy treatments

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Ovalle, S. A.; Barquero, R.; Gomez-Ros, J. M.; Lallena, A. M. [Grupo de Fisica Nuclear Aplicada y Simulacion, Universidad Pedagogica y Tecnologica de Colombia, Tunja 15001000 (Colombia); Servicio de Proteccion Radiologica, Hospital Clinico Universitario, E-47012 Valladolid (Spain) and Departamento de Radiologia, Universidad de Valladolid, Valladolid E-47071 (Spain); CIEMAT, Avda. Complutense 40, Madrid, E-28040 (Spain); Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, Granada E-18071 (Spain)

    2012-05-15

    Purpose: To calculate absorbed doses due to neutrons in 87 organs/tissues for anthropomorphic phantoms, irradiated in position supine (head first into the gantry) with orientations anteroposterior (AP) and right-left (RLAT) with a 18 MV accelerator. Conversion factors from monitor units to {mu}Gy per neutron in organs, equivalent doses in organs/tissues, and effective doses, which permit to quantify stochastic risks, are estimated. Methods: MAX06 and FAX06 phantoms were modeled with MCNPX and irradiated with a 18 MV Varian Clinac 2100C/D accelerator whose geometry included a multileaf collimator. Two actual fields of a pelvic treatment were simulated using electron-photon-neutron coupled transport. Absorbed doses due to neutrons were estimated from kerma. Equivalent doses were estimated using the radiation weighting factor corresponding to an average incident neutron energy 0.47 MeV. Statistical uncertainties associated to absorbed doses, as calculated by MCNPX, were also obtained. Results: Largest doses were absorbed in shallowest (with respect to the neutron pathway) organs. In {mu}GyMU{sup -1}, values of 2.66 (for penis) and 2.33 (for testes) were found in MAX06, and 1.68 (for breasts), 1.05 (for lenses of eyes), and 0.94 (for sublingual salivary glands) in FAX06, in AP orientation. In RLAT, the largest doses were found for bone tissues (leg) just at the entrance of the beam in the body (right side in our case). Values, in {mu}GyMU{sup -1}, of 1.09 in upper leg bone right spongiosa, for MAX06, and 0.63 in mandible spongiosa, for FAX06, were found. Except for gonads, liver, and stomach wall, equivalent doses found for FAX06 were, in both orientations, higher than for MAX06. Equivalent doses in AP are higher than in RLAT for all organs/tissues other than brain and liver. Effective doses of 12.6 and 4.1 {mu}SvMU{sup -1} were found for AP and RLAT, respectively. The organs/tissues with larger relative contributions to the effective dose were testes and breasts, in

  2. Infrared (IR) vs x-ray power generation in the SLAC Linac Coherent Light Source (LCLS)

    International Nuclear Information System (INIS)

    Tatchyn, R.

    1993-05-01

    The LCLS, a Free-Electron Laser (FEL) designed for operation at a first harmonic energy of 300 eV (λ congruent 40 Angstrom) in the Self-Amplified Spontaneous Emission (SASE) regime, will utilize electron bunches compressed down to durations of <0.5ps, or lengths of <150 μ. It is natural to inquire whether coherent radiation of this (and longer) wavelength will constitute a significant component of the total coherent output of the FEL. In this paper a determination of a simple upper bound on the IR that can be generated by the compressed bunches is outlines. Under the assumed operating parameters of the LCLS undulator, it is shown that that IR component of the coherent output should be strongly dominated by the x-ray component

  3. Compact Neutron Generators for Medical, Home Land Security, and Planetary Exploration

    CERN Document Server

    Reijonen, Jani

    2005-01-01

    The Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory has developed various types of advanced D-D (neutron energy 2.5 MeV), D-T (14 MeV) and T-T (0 - 9 MeV) neutron generators for wide range of applications. These applications include medical (Boron Neutron Capture Therapy), homeland security (Prompt Gamma Activation Analysis, Fast Neutron Activation Analysis and Pulsed Fast Neutron Transmission Spectroscopy) and planetary exploration in form of neutron based, sub-surface hydrogen detection systems. These neutron generators utilize RF induction discharge to ionize the deuterium/tritium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. Three main neutron generator developments are discussed here: high neutron output co-axial neutron generator for BNCT applications, point neutron generator for security applications, compact and sub-c...

  4. Intense neutron irradiation facility for fusion reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    Noda, Kenji; Oyama, Yukio; Kato, Yoshio; Sugimoto, Masayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    Technical R and D of d-Li stripping type neutron irradiation facilities for development of fusion reactor materials was carried out in Fusion Materials Irradiation Test Facility (FMIT) project and Energy Selective Neutron Irradiation Test Facility (ESNIT) program. Conceptual design activity (CDA) of International Fusion Materials Irradiation Facility (IFMIF), of which concept is an advanced version of FMIT and ESNIT concepts, are being performed. Progress of users` requirements and characteristics of irradiation fields in such neutron irradiation facilities, and outline of baseline conceptual design of IFMIF were described. (author)

  5. Utilizations of intense pulsed neutron source in radiochemistry and radiation chemistry

    International Nuclear Information System (INIS)

    Shiokawa, Takanobu; Yoshihara, Kenji; Kaji, Harumi; Kusaka, Yuzuru; Tabata, Yoneho.

    1975-01-01

    Intense pulsed neutron sources is expected to supply more useful and fundamental informations in radiochemistry and radiation chemistry. Short-lived intermediate species may be detected and the mechanisms of radiation induced reactions will be elucidated more precisely. Analytical application of pulsed neutrons is also very useful. (auth.)

  6. Neutron radiation characteristics of the IVth generation reactor spent fuel

    Science.gov (United States)

    Bedenko, Sergey; Shamanin, Igor; Grachev, Victor; Knyshev, Vladimir; Ukrainets, Olesya; Zorkin, Andrey

    2018-03-01

    Exploitation of nuclear power plants as well as construction of new generation reactors lead to great accumulation of spent fuel in interim storage facilities at nuclear power plants, and in spent fuel «wet» and «dry» long-term storages. Consequently, handling the fuel needs more attention. The paper is focused on the creation of an efficient computational model used for developing the procedures and regulations of spent nuclear fuel handling in nuclear fuel cycle of the new generation reactor. A Thorium High-temperature Gas-Cooled Reactor Unit (HGTRU, Russia) was used as an object for numerical research. Fuel isotopic composition of HGTRU was calculated using the verified code of the MCU-5 program. The analysis of alpha emitters and neutron radiation sources was made. The neutron yield resulting from (α,n)-reactions and at spontaneous fission was calculated. In this work it has been shown that contribution of (α,n)-neutrons is insignificant in case of such (Th,Pu)-fuel composition and HGTRU operation mode, and integral neutron yield can be approximated by the Watt spectral function. Spectral and standardized neutron distributions were achieved by approximation of the list of high-precision nuclear data. The distribution functions were prepared in group and continuous form for further use in calculations according to MNCP, MCU, and SCALE.

  7. Radiation protection aspects of a high flux, fast neutron generator

    International Nuclear Information System (INIS)

    DeLuca, P.M.; Torti, R.P.; Chenevert, G.M.; Tesmer, J.R.; Kelsey, C.A.

    1976-01-01

    During the development and operation of a gas target, DT neutron generator for use in cancer therapy, two radiation hazards were routinely encountered - personnel exposure to neutrons and to tritium. The principal hazard was irradiation by fast neutrons. By assembling the source below ground level, adding shielding and the use of a controlled access, key identification interlock, the neutron hazard has been reduced. With the present source strength of 2 x 10 12 n/sec, an average neutron dose rate in the control room of 20 mrem/hr was measured- a level compatible with a limited run schedule. The second hazard was exposure to tritium in both gaseous and solid forms. A target inventory of 90 Ci, and overall inventory of 500 Ci, and the need to modify and repair the generator present significant potential hazard due to tritium exposure. The use of protective gloves, wipe tests, urine assays, continuous room air monitoring, and equipment decontamination minimized personnel exposure and effectively confined contamination. The dose due to tritium has been ∼ 0.5 rem/year and negligible spread of contamination has occurred

  8. Conceptual designs of beam choppers for RFQ linacs

    International Nuclear Information System (INIS)

    Nath, S.; Stevens, S.R. Jr.; Wangler, T.P.

    1995-01-01

    A design study at Los Alamos of a linac/accumulator ring facility for a pulsed neutron spallation source calls for an H - beam with a chopped structure of approximately 200-ns beam-free segments every 600-ns. The required angular impulse can easily be provided with existing pulse power technology and traveling wave structures with a transverse electric field similar to those now available. The deflected beam is then restored by suitable collimation. Chopping is relatively easily done at sufficiently low energies, where the beam is easily deflected, and beam powers are not too large. However, the energy should be high enough so that the space-charge blow-up of the beam can be controlled with adequate focusing. LAMPF presently uses a traveling-wave beam chopper at 750 keV, before injection into the drift tube linac (DTL). In the new linac designs, a radiofrequency quadrupole (RFQ) linac would typically bunch and accelerate the high intensity H - beam from 100 keV to 7 MeV. In this paper, the authors present concepts for beam-chopper systems both before and after the RFQ. The beam-optics designs are presented, together with numerical simulation results

  9. Assessment of the gas dynamic trap mirror facility as intense neutron source for fusion material test irradiations

    International Nuclear Information System (INIS)

    Fischer, U.; Moeslang, A.; Ivanov, A.A.

    2000-01-01

    The gas dynamic trap (GDT) mirror machine has been proposed by the Budker Institute of nuclear physics, Novosibirsk, as a volumetric neutron source for fusion material test irradiations. On the basis of the GDT plasma confinement concept, 14 MeV neutrons are generated at high production rates in the two end sections of the axially symmetrical central mirror cell, serving as suitable irradiation test regions. In this paper, we present an assessment of the GDT as intense neutron source for fusion material test irradiations. This includes comparisons to irradiation conditions in fusion reactor systems (ITER, Demo) and the International Fusion Material Irradiation Facility (IFMIF), as well as a conceptual design for a helium-cooled tubular test assembly elaborated for the largest of the two test zones taking proper account of neutronics, thermal-hydraulic and mechanical aspects. This tubular test assembly incorporates ten rigs of about 200 cm length used for inserting instrumented test capsules with miniaturized specimens taking advantage of the 'small specimen test technology'. The proposed design allows individual temperatures in each of the rigs, and active heating systems inside the capsules ensures specimen temperature stability even during beam-off periods. The major concern is about the maximum achievable dpa accumulation of less than 15 dpa per full power year on the basis of the present design parameters of the GDT neutron source. A design upgrading is proposed to allow for higher neutron wall loadings in the material test regions

  10. Conceptual design of a high-intensity positron source for the Advanced Neutron Source

    International Nuclear Information System (INIS)

    Hulett, L.D.; Eberle, C.C.

    1994-12-01

    The Advanced Neutron Source (ANS) is a planned new basic and applied research facility based on a powerful steady-state research reactor that provides neutrons for measurements and experiments in the fields of materials science and engineering, biology, chemistry, materials analysis, and nuclear science. The useful neutron flux will be at least five times more than is available in the world's best existing reactor facility. Construction of the ANS provides a unique opportunity to build a positron spectroscopy facility (PSF) with very-high-intensity beams based on the radioactive decay of a positron-generating isotope. The estimated maximum beam current is 1000 to 5000 times higher than that available at the world's best existing positron research facility. Such an improvement in beam capability, coupled with complementary detectors, will reduce experiment durations from months to less than one hour while simultaneously improving output resolution. This facility will remove the existing barriers to the routine use of positron-based analytical techniques and will be a giant step toward realization of the full potential of the application of positron spectroscopy to materials science. The ANS PSF is based on a batch cycle process using 64 Cu isotope as the positron emitter and represents the status of the design at the end of last year. Recent work not included in this report, has led to a proposal for placing the laboratory space for the positron experiments outside the ANS containment; however, the design of the positron source is not changed by that relocation. Hydraulic and pneumatic flight tubes transport the source material between the reactor and the positron source where the beam is generated and conditioned. The beam is then transported through a beam pipe to one of several available detectors. The design presented here includes all systems necessary to support the positron source, but the beam pipe and detectors have not been addressed yet

  11. Manual for troubleshooting and upgrading of neutron generators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-11-01

    This manual is intended to assist operators in troubleshooting and upgrading of neutron generators. It is directed particularly to operators and technicians in less experienced laboratories and therefore the descriptions of the principles and techniques of these machines are operator oriented. In addition to a discussion of the main characteristics of neutron generators, detailed information is given on the function of particular commercial units, on common problems related to specific components of accelerators, and on methods of troubleshooting and repair. Detailed schematic and circuit diagrams are provided to help operators in the development and improvement of the generators. The problems treated in the Manual have been collected during several IAEA missions in developing countries. 125 refs, 161 figs, 22 tabs.

  12. Manual for troubleshooting and upgrading of neutron generators

    International Nuclear Information System (INIS)

    1996-11-01

    This manual is intended to assist operators in troubleshooting and upgrading of neutron generators. It is directed particularly to operators and technicians in less experienced laboratories and therefore the descriptions of the principles and techniques of these machines are operator oriented. In addition to a discussion of the main characteristics of neutron generators, detailed information is given on the function of particular commercial units, on common problems related to specific components of accelerators, and on methods of troubleshooting and repair. Detailed schematic and circuit diagrams are provided to help operators in the development and improvement of the generators. The problems treated in the Manual have been collected during several IAEA missions in developing countries. 125 refs, 161 figs, 22 tabs

  13. Neutron monitor generated data distributions in quantum variational Monte Carlo

    Science.gov (United States)

    Kussainov, A. S.; Pya, N.

    2016-08-01

    We have assessed the potential applications of the neutron monitor hardware as random number generator for normal and uniform distributions. The data tables from the acquisition channels with no extreme changes in the signal level were chosen as the retrospective model. The stochastic component was extracted by fitting the raw data with splines and then subtracting the fit. Scaling the extracted data to zero mean and variance of one is sufficient to obtain a stable standard normal random variate. Distributions under consideration pass all available normality tests. Inverse transform sampling is suggested to use as a source of the uniform random numbers. Variational Monte Carlo method for quantum harmonic oscillator was used to test the quality of our random numbers. If the data delivery rate is of importance and the conventional one minute resolution neutron count is insufficient, we could always settle for an efficient seed generator to feed into the faster algorithmic random number generator or create a buffer.

  14. Pathways to agility in the production of neutron generators

    Energy Technology Data Exchange (ETDEWEB)

    Stoltz, R.E. [Sandia National Labs., Livermore, CA (United States); Beavis, L.C.; Cutchen, J.T.; Garcia, P.; Gurule, G.A.; Harris, R.N.; McKey, P.C.; Williams, D.W. [Sandia National Labs., Albuquerque, NM (United States)

    1994-02-01

    This report is the result of a study team commissioned to explore pathways for increased agility in the manufacture of neutron generators. As a part of Sandia`s new responsibility for generator production, the goal of the study was to identify opportunities to reduce costs and increase flexibility in the manufacturing operation. Four parallel approaches (or pathways) were recommended: (1) Know the goal, (2) Use design leverage effectively, (3) Value simplicity, and (4) Configure for flexibility. Agility in neutron generator production can be enhanced if all of these pathways are followed. The key role of the workforce in achieving agility was also noted, with emphasis on ownership, continuous learning, and a supportive environment.

  15. Current Status and Progress of Developing a D-D Neutron Generator

    International Nuclear Information System (INIS)

    Kim, In-Jung; Jung, Hwa-Dong; Park, Chang-Su; Jung, Nam-Suk; Chung, Kyoung-Jae; Hwang, Yong-Seok; Choi, H. D.

    2006-01-01

    The research to develop a D-D neutron generator was begun in 2001. A prototype device was built in 2004, and partly modified in 2005. By using the modified prototype D-D neutron generator, neutron generation runs were performed, and the characteristics of D-D neutron generation was investigated. The final goal of maximum neutron yield is 10 8 n/s, while a yield of 6.5x10 7 n/s has been achieved. Here, the results of neutron generation runs performed by using the modified prototype device are summarized, and the feature of a new ion source to be tested in weeks is briefly described

  16. Higher-order-mode (HOM) power in elliptical superconducting cavities for intense pulsed proton accelerators

    CERN Document Server

    Sang Ho Kim; Dong O Jeon; Sundeli, R

    2002-01-01

    In linacs for intense pulsed proton accelerators, the beam has a multiple time-structure, and each beam time-structure generates resonance. When a higher-order mode (HOM) is near these resonance frequencies, the induced voltage could be large and accordingly the resulting HOM power, too. In order to understand the effects of a complex beam time-structure on the mode excitations and the resulting HOM powers in elliptical superconducting cavities, analytic expressions are developed, with which the beam-induced voltage and corresponding power are explored, taking into account the properties of HOM frequency behavior in elliptical superconducting cavities. The results and understandings from this analysis are presented with the beam parameters of the Spallation Neutron Source (SNS) superconducting linac.

  17. Design of intense neutron source for fusion material study and the role of universities

    International Nuclear Information System (INIS)

    Ishino, Shiori

    1993-01-01

    Need and requirement for the intense neutron source for fusion materials study have been discussed for many years. Recently, international climate has been becoming gradually maturing to consider this problem more seriously because of the recognition of crucial importance of solving materials problems for fusion energy development. The present symposium was designed to discuss the problems associated with the intense neutron source for material irradiation studies which will have a potential for the National Institute for Fusion Science to become one of the important future research areas. The symposium comprises five sessions; first, the role of materials research in fusion development strategies was discussed followed by a brief summary of current IFMIF (International Fusion Materials Irradiation Facility) activity. Despite the pressing need for intense fusion neutron source, currently available neutron sources are reactor or accelerator based sources of which FFTF and LASREF were discussed. Then, various concepts of intense neutron source candidates were presented including ESNIT, which are currently under design by JAERI. In the fourth session, discussions were made on the study of materials with the intense neutron source from the viewpoint of materials scientists and engineers as the user of the facility. This is followed by discussions on the role of universities from the two stand points, namely, fusion irradiation studies and fusion materials development. Finally summary discussions were made by the participants, indicating important role fundamental studies in universities for the full utilization of irradiation data and the need of pure 14 MeV neutron source for fundamental studies together with the intense surrogate neutron sources. (author)

  18. Fermilab Linac Upgrade Conceptual Design: Revision 3

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    1989-07-01

    The goal of the Tevatron Collider Upgrade program is to improve the Collider luminosity and the fixed-target intensity. The Linac portion of this project will increase the energy of the existing 200- MeV linac to 400 MeV in order to reduce beam emittance degradation in the Booster.

  19. 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.

  20. A Monte Carlo investigation of low-Z target image quality generated in a linear accelerator using Varian's VirtuaLinac

    International Nuclear Information System (INIS)

    Parsons, David; Robar, James L.; Sawkey, Daren

    2014-01-01

    Purpose: The focus of this work was the demonstration and validation of VirtuaLinac with clinical photon beams and to investigate the implementation of low-Z targets in a TrueBeam linear accelerator (Linac) using Monte Carlo modeling. Methods: VirtuaLinac, a cloud based web application utilizing Geant4 Monte Carlo code, was used to model the Linac treatment head components. Particles were propagated through the lower portion of the treatment head using BEAMnrc. Dose distributions and spectral distributions were calculated using DOSXYZnrc and BEAMdp, respectively. For validation, 6 MV flattened and flattening filter free (FFF) photon beams were generated and compared to measurement for square fields, 10 and 40 cm wide and at d max for diagonal profiles. Two low-Z targets were investigated: a 2.35 MeV carbon target and the proposed 2.50 MeV commercial imaging target for the TrueBeam platform. A 2.35 MeV carbon target was also simulated in a 2100EX Clinac using BEAMnrc. Contrast simulations were made by scoring the dose in the phosphor layer of an IDU20 aSi detector after propagating through a 4 or 20 cm thick phantom composed of water and ICRP bone. Results: Measured and modeled depth dose curves for 6 MV flattened and FFF beams agree within 1% for 98.3% of points at depths greater than 0.85 cm. Ninety three percent or greater of points analyzed for the diagonal profiles had a gamma value less than one for the criteria of 1.5 mm and 1.5%. The two low-Z target photon spectra produced in TrueBeam are harder than that from the carbon target in the Clinac. Percent dose at depth 10 cm is greater by 3.6% and 8.9%; the fraction of photons in the diagnostic energy range (25–150 keV) is lower by 10% and 28%; and contrasts are lower by factors of 1.1 and 1.4 (4 cm thick phantom) and 1.03 and 1.4 (20 cm thick phantom), for the TrueBeam 2.35 MV/carbon and commercial imaging beams, respectively. Conclusions: VirtuaLinac is a promising new tool for Monte Carlo modeling of novel

  1. The first IEC fusion industrial neutron generator and developments

    Science.gov (United States)

    Sved, John

    1999-06-01

    Inertial Electrostatic Confinement fusion grade plasma containment has been sporadically researched since the early 1960's. In the 1990's the work of G. H. Miley and his team at the University of Illinios, Fusion Studies Laboratory, Champaign-Urbana has stimulated a collaboration with industry. The development and test program for the first industrial IEC neutron generator has progressed to the point where an endurance test is under way to demonstrate at least 10,000 hours of operational life of the sealed chamber device without servicing. The market entry goals of steady 107 D-D n/s CW output with an air-cooled system have been achieved. DASA has invested in the development of the industrial product and the continuing basic research at the UI-FSL. The complete DASA FusionStar IEC-PS1 point source neutron generator set is described with emphasis on the interfaces to user NAA systems. The next product developments are pulsed neutron operations and higher fusion reaction rates of up to 1010 by means of affordable add-ons to the basic IEC-PS system. The production engineering experience gained will next be applied to a more challenging line source variant of the IEC. Beyond neutron and proton sources, several other IEC applications are being developed.

  2. Inner structure of Linac 2

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    With the advent of the 800 MeV Booster in 1972, the original injector of the PS, a 50 MeV Alvarez-type proton linac, had reached its limits, in terms of intensity and stability. In 1973 one therefore decided to build a new linac (Linac 2), also with a drift-tube Alvarez structure and an energy of 50 MeV. It had a new Cockcroft-Walton preinjector with 750 keV, instead of the previous one with 500 keV. Linac 2 was put into service in 1980. The old Linac 1 was then used for the study of, and later operation with, various types of ions. This picture shows the inner structure of Linac 2, with drift-tubes hanging on stems under a rigid support structure, soon to be mounted inside tank 1 (750 keV to 10 MeV, the lowest-energy one of 3). Frank Malthouse is standing in the background.

  3. New perspectives from new generations of neutron sources

    Science.gov (United States)

    Mezei, Ferenc

    2007-09-01

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

  4. New perspectives from new generations of neutron sources

    International Nuclear Information System (INIS)

    Mezei, F.

    2007-01-01

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

  5. Shielding evaluation of neutron generator hall by Monte Carlo simulations

    Energy Technology Data Exchange (ETDEWEB)

    Pujala, U.; Selvakumaran, T.S.; Baskaran, R.; Venkatraman, B. [Radiological Safety Division, Indira Gandhi Center for Atomic Research, Kalpakkam (India); Thilagam, L.; Mohapatra, D.K., E-mail: swathythila2@yahoo.com [Safety Research Institute, Atomic Energy Regulatory Board, Kalpakkam (India)

    2017-04-01

    A shielded hall was constructed for accommodating a D-D, D-T or D-Be based pulsed neutron generator (NG) with 4π yield of 10{sup 9} n/s. The neutron shield design of the facility was optimized using NCRP-51 methodology such that the total dose rates outside the hall areas are well below the regulatory limit for full occupancy criterion (1 μSv/h). However, the total dose rates at roof top, cooling room trench exit and labyrinth exit were found to be above this limit for the optimized design. Hence, additional neutron shielding arrangements were proposed for cooling room trench and labyrinth exits. The roof top was made inaccessible. The present study is an attempt to evaluate the neutron and associated capture gamma transport through the bulk shields for the complete geometry and materials of the NG-Hall using Monte Carlo (MC) codes MCNP and FLUKA. The neutron source terms of D-D, D-T and D-Be reactions are considered in the simulations. The effect of additional shielding proposed has been demonstrated through the simulations carried out with the consideration of the additional shielding for D-Be neutron source term. The results MC simulations using two different codes are found to be consistent with each other for neutron dose rate estimates. However, deviation up to 28% is noted between these two codes at few locations for capture gamma dose rate estimates. Overall, the dose rates estimated by MC simulations including additional shields shows that all the locations surrounding the hall satisfy the full occupancy criteria for all three types of sources. Additionally, the dose rates due to direct transmission of primary neutrons estimated by FLUKA are compared with the values calculated using the formula given in NCRP-51 which shows deviations up to 50% with each other. The details of MC simulations and NCRP-51 methodology for the estimation of primary neutron dose rate along with the results are presented in this paper. (author)

  6. Fast and thermal neutron intensity measurements at the KFUPM PGNAA setup

    CERN Document Server

    Al-Jarallah, M I; Fazal-Ur-Rehman; Abu-Jarad, F A

    2002-01-01

    Fast and thermal neutron intensity distributions have been measured at an accelerator based prompt gamma ray neutron activation analysis (PGNAA) setup. The setup is built at the 350 keV accelerator laboratory of King Fahd University of Petroleum and Minerals (KFUPM). The setup is mainly designed to carry out PGNAA elemental analysis via thermal neutron capture. In this study relative intensity of fast and thermal neutrons was measured as a function of the PGNAA moderator assembly parameters using nuclear track detectors (NTDs). The relative intensity of the neutrons was measured inside the sample region as a function of front moderator thickness as well as sample length. Measurements were carried out at the KFUPM 350 keV accelerator using 2.8 MeV pulsed neutron beam from D(d,n) reaction. The pulsed deuteron beam with 5 ns pulse width and 30 kHz frequency was used to produce neutrons. Experimental results were compared with results of Monte Carlo design calculations of the PGNAA setup. A good agreement has bee...

  7. Fast and thermal neutron intensity measurements at the KFUPM PGNAA setup

    Energy Technology Data Exchange (ETDEWEB)

    Al-Jarallah, M.I.; Naqvi, A.A. E-mail: aanaqvi@kfupm.edu.sa; Fazal-ur-Rehman; Abu-jarad, F

    2002-10-01

    Fast and thermal neutron intensity distributions have been measured at an accelerator based prompt gamma ray neutron activation analysis (PGNAA) setup. The setup is built at the 350 keV accelerator laboratory of King Fahd University of Petroleum and Minerals (KFUPM). The setup is mainly designed to carry out PGNAA elemental analysis via thermal neutron capture. In this study relative intensity of fast and thermal neutrons was measured as a function of the PGNAA moderator assembly parameters using nuclear track detectors (NTDs). The relative intensity of the neutrons was measured inside the sample region as a function of front moderator thickness as well as sample length. Measurements were carried out at the KFUPM 350 keV accelerator using 2.8 MeV pulsed neutron beam from D(d,n) reaction. The pulsed deuteron beam with 5 ns pulse width and 30 kHz frequency was used to produce neutrons. Experimental results were compared with results of Monte Carlo design calculations of the PGNAA setup. A good agreement has been found between the experimental results and the calculations.

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

    International Nuclear Information System (INIS)

    Sumita, Kenji

    1988-01-01

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

  9. Superpower proton linear accelerators for neutron generators and electronuclear facilities

    International Nuclear Information System (INIS)

    Lazarev, N.V.; Kozodaev, A.M.

    2000-01-01

    The report is a review of projects on the superpower proton linear accelerators (SPLA) for neutron generators (NG) and electronuclear facilities, proposed in the recent years. The beam average output capacity in these projects reaches 100 MW. The basic parameters of certain operating NGs, as well as some projected NGs will the SPLA drivers are presented. The problems on application of superconducting resonators in the SPLA as well as the issues of the SPLA reliability and costs are discussed [ru

  10. A liquid hydrocarbon deuteron source for neutron generators

    Science.gov (United States)

    Schwoebel, P. R.

    2017-06-01

    Experimental studies of a deuteron spark source for neutron generators using hydrogen isotope fusion reactions are reported. The ion source uses a spark discharge between electrodes coated with a deuterated hydrocarbon liquid, here Santovac 5, to inhibit permanent electrode erosion and extend the lifetime of high-output neutron generator spark ion sources. Thompson parabola mass spectra show that principally hydrogen and deuterium ions are extracted from the ion source. Hydrogen is the chief residual gas phase species produced due to source operation in a stainless-steel vacuum chamber. The prominent features of the optical emission spectra of the discharge are C+ lines, the hydrogen Balmer Hα-line, and the C2 Swan bands. Operation of the ion source was studied in a conventional laboratory neutron generator. The source delivered an average deuteron current of ˜0.5 A nominal to the target in a 5 μs duration pulse at 1 Hz with target voltages of -80 to -100 kV. The thickness of the hydrocarbon liquid in the spark gap and the consistency thereof from spark to spark influences the deuteron yield and plays a role in determining the beam-focusing characteristics through the applied voltage necessary to break down the spark gap. Higher breakdown voltages result in larger ion beam spots on the target and vice-versa. Because the liquid self-heals and thereby inhibits permanent electrode erosion, the liquid-based source provides long life, with 104 pulses to date, and without clear evidence that, in principle, the lifetime could not be much longer. Initial experiments suggest that an alternative cylindrical target-type generator design can extract approximately 10 times the deuteron current from the source. Preliminary data using the deuterated source liquid as a neutron-producing target are also presented.

  11. Transmutation studies of minor actinides in high intensity neutron fluxes

    International Nuclear Information System (INIS)

    Fioni, G.; Bolognese, T.; Cribier, M.; Marie, F.; Roettger, S.; Faust, H.; Leconte, Ph.

    1999-01-01

    Integral measurements of nuclear data and of the transmutation potential in specific neutron fluxes, constitute the fastest and essential way to overcome to the large uncertainties present in the nuclear data libraries. In the frame of the activities of the Directorate for Science of Matter (DSM) of the French Atomic Energy Authority (CEA), a new project is proposed so as to carry out integral measurements relevant for nuclear waste transmutation systems. A new beam tube will be installed to irradiate actinides and fission fragment samples at different distances from the fuel element of the ILL reactor. Variable neutron energy spectra could then be obtained by choosing the distance between the sample and the fuel element, opening the way to the determination of the ideal physical conditions to incinerate nuclear waste in hybrid transmutation systems. (author)

  12. Status of the SNS Linac An Overview

    CERN Document Server

    Holtkamp, N

    2004-01-01

    The Spallation Neutron Source SNS is a second generation pulsed neutron source and under construction at Oak Ridge National Laboratory. The SNS is funded by the U.S. Department of Energy?s Office of Basic energy Sciences and is dedicated to the study of the structure and dynamics of materials by neutron scattering. A collaboration composed of six national laboratories (ANL, BNL, TJNAF, LANL, LBNL, ORNL) is responsible for the design and construction of the various subsystems. With the official start in October 1998, the operation of the facility will begin in 2006 and deliver a 1.0 GeV, 1.4 MW proton beam with a pulse length of approximately 700 nanoseconds on a liquid mercury target. The multi-lab collaboration allowed access to a large variety of expertise in order to enhance the delivered beam power by almost an order of magnitude compared to existing neutron facilities. The SNS linac consists of a combination of room temperature and superconducting structures and will be the first pulsed high power sc lin...

  13. Investigation of Workplace-like Calibration Fields via a Deuterium-Tritium (D-T) Neutron Generator.

    Science.gov (United States)

    Mozhayev, Andrey V; Piper, Roman K; Rathbone, Bruce A; McDonald, Joseph C

    2017-04-01

    Radiation survey meters and personal dosimeters are typically calibrated in reference neutron fields based on conventional radionuclide sources, such as americium-beryllium (Am-Be) or californium-252 (Cf), either unmodified or heavy-water moderated. However, these calibration neutron fields differ significantly from the workplace fields in which most of these survey meters and dosimeters are being used. Although some detectors are designed to yield an approximately dose-equivalent response over a particular neutron energy range, the response of other detectors is highly dependent upon neutron energy. This, in turn, can result in significant over- or underestimation of the intensity of neutron radiation and/or personal dose equivalent determined in the work environment. The use of simulated workplace neutron calibration fields that more closely match those present at the workplace could improve the accuracy of worker, and workplace, neutron dose assessment. This work provides an overview of the neutron fields found around nuclear power reactors and interim spent fuel storage installations based on available data. The feasibility of producing workplace-like calibration fields in an existing calibration facility has been investigated via Monte Carlo simulations. Several moderating assembly configurations, paired with a neutron generator using the deuterium tritium (D-T) fusion reaction, were explored.

  14. A proposal of neutron science research program

    International Nuclear Information System (INIS)

    Suzuki, Y.; Yasuda, H.; Tone, T.; Mizumoto, M.

    1996-01-01

    A conception of Neutron Science Research Program (NSRP) has been proposed in Japan Atomic Energy Research Institute (JAERI) since 1994 as a future big project. The NSRP aims at exploring new basic science and nuclear energy science by a high-intensity proton accelerator. It is a complex composed of a proton linac and seven research facilities with each different target system. The proton linac is required to supply the high-intensity proton beam with energy up to 1.5 GeV and current 10 mA on average. The scientific research facilities proposed, are as follows: Thermal/Cold Neutron Facility for the neutron scattering experiments, Neutron Irradiation Facility for materials science, Neutron Physics Facility for nuclear data measurement, OMEGA/Nuclear Energy Facility for nuclear waste transmutation and fuel breeding, Spallation RI Beam Facility for nuclear physics, Meson/Muon Facility for meson and muon physics and their applications and Medium Energy Beam Facility for accelerator technology development, medical use, etc. Research and development have been carried out for the components of the injector system of the proton linac; an ion source, an RFQ linac and a part of DTL linac. The conceptual design work and research and development activities for NSRP have been started in the fiscal year, 1996. Construction term will be divided into two phases; the completion of the first phase is expected in 2003, when the proton linac will produce 1.5 GeV, 1 mA beam by reflecting the successful technology developments. (author)

  15. SU-E-T-569: Evaluation of VMAT Plans Generated with HD120 and Millennium 120 MLC Between Two Matched Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Cui, G; Ballas, L; Chang, E; Chung, E; Chiu, R; Cummings, D; Shiu, A [University Southern California, Los Angeles, CA (United States)

    2014-06-01

    Purpose: To evaluate VMAT treatment plans generated with HD120 MLC and Millennium 120 MLC between two matched linacs and to determine if one can back up the other. Methods: The 6x photon beams are matched for our Varian TrueBeam STx and Trilogy linacs, which are equipped with HD120 MLC and Millennium 120 MLC, respectively. Three prostate and three brain VMAT plans were used for the evaluation. Five plans (three prostate and two brain plans) were originally generated with the TrueBeam STx and re-computed with the Trilogy. One brain plan was evaluated the other way around. For each plan, the PTV coverage of V95 was made the same between two linacs. The dosimetric differences associated with the plans were compared using: 1) Percentage mean dose differences to the PTV, 2) Homogeneity index, HI = (Dmax − Dmin)/Dmean for the PTV. For prostate plans, the mean dose differences to the rectum were evaluated. While for brain plans, the percentage max dose differences to the lenses (left and right lens) were evaluated. Results: For three prostate plans, the average of the percentage mean dose differences to the PTV was 0.5 ± 0.1% and the HI was 0.1 ± 0.0%. The average of the percentage mean dose difference to the rectum was 3.5 ± 0.5%. For three brain plans, the average of the percentage mean dose differences to the PTV was 0.2 ± 1.1% and the HI was 0.2 ± 0.1%. The average of the percentage max dose differences to the lenses was 22.9 ± 4.0%. Conclusion: For prostate VMAT plans, changing the treatment from the TrueBeam STx to the Trilogy does not necessarily need re-optimization. But for brain plans, in order to minimize dose to the lenses, it is recommended to re-optimize the plan if changing the treatment between these two linacs.

  16. SU-E-T-569: Evaluation of VMAT Plans Generated with HD120 and Millennium 120 MLC Between Two Matched Linacs

    International Nuclear Information System (INIS)

    Cui, G; Ballas, L; Chang, E; Chung, E; Chiu, R; Cummings, D; Shiu, A

    2014-01-01

    Purpose: To evaluate VMAT treatment plans generated with HD120 MLC and Millennium 120 MLC between two matched linacs and to determine if one can back up the other. Methods: The 6x photon beams are matched for our Varian TrueBeam STx and Trilogy linacs, which are equipped with HD120 MLC and Millennium 120 MLC, respectively. Three prostate and three brain VMAT plans were used for the evaluation. Five plans (three prostate and two brain plans) were originally generated with the TrueBeam STx and re-computed with the Trilogy. One brain plan was evaluated the other way around. For each plan, the PTV coverage of V95 was made the same between two linacs. The dosimetric differences associated with the plans were compared using: 1) Percentage mean dose differences to the PTV, 2) Homogeneity index, HI = (Dmax − Dmin)/Dmean for the PTV. For prostate plans, the mean dose differences to the rectum were evaluated. While for brain plans, the percentage max dose differences to the lenses (left and right lens) were evaluated. Results: For three prostate plans, the average of the percentage mean dose differences to the PTV was 0.5 ± 0.1% and the HI was 0.1 ± 0.0%. The average of the percentage mean dose difference to the rectum was 3.5 ± 0.5%. For three brain plans, the average of the percentage mean dose differences to the PTV was 0.2 ± 1.1% and the HI was 0.2 ± 0.1%. The average of the percentage max dose differences to the lenses was 22.9 ± 4.0%. Conclusion: For prostate VMAT plans, changing the treatment from the TrueBeam STx to the Trilogy does not necessarily need re-optimization. But for brain plans, in order to minimize dose to the lenses, it is recommended to re-optimize the plan if changing the treatment between these two linacs

  17. Status of spallation neutron source program in High Intensity Proton Accelerator Project

    International Nuclear Information System (INIS)

    Oyama, Yukio

    2001-01-01

    Japan Atomic Energy Research Institute and High Energy Accelerator Organization are jointly designing a 1 MW spallation neutron source as one of the research facilities planned in the High Intensity Proton Accelerator Project. The spallation neutron source is driven by 3 GeV proton beam with a mercury target and liquid hydrogen moderators. The present status of design for these spallation source and relevant facility is overviewed. (author)

  18. Development of a new deuterium-deuterium (D-D) neutron generator for prompt gamma-ray neutron activation analysis.

    Science.gov (United States)

    Bergaoui, K; Reguigui, N; Gary, C K; Brown, C; Cremer, J T; Vainionpaa, J H; Piestrup, M A

    2014-12-01

    A new deuterium-deuterium (D-D) neutron generator has been developed by Adelphi Technology for prompt gamma neutron activation analysis (PGNAA), neutron activation analysis (NAA), and fast neutron radiography. The generator makes an excellent fast, intermediate, and thermal neutron source for laboratories and industrial applications that require the safe production of neutrons, a small footprint, low cost, and small regulatory burden. The generator has three major components: a Radio Frequency Induction Ion Source, a Secondary Electron Shroud, and a Diode Accelerator Structure and Target. Monoenergetic neutrons (2.5MeV) are produced with a yield of 10(10)n/s using 25-50mA of deuterium ion beam current and 125kV of acceleration voltage. The present study characterizes the performance of the neutron generator with respect to neutron yield, neutron production efficiency, and the ionic current as a function of the acceleration voltage at various RF powers. In addition the Monte Carlo N-Particle Transport (MCNP) simulation code was used to optimize the setup with respect to thermal flux and radiation protection. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. The neutrons generator becomes miniature; Le generateur de neutrons se miniaturise

    Energy Technology Data Exchange (ETDEWEB)

    Boulben, A

    2005-05-01

    A mini neutrons generator has been designed by researchers of the California university of Los Angeles which does not need any high voltage power supply ar any radioactive element. The system comprises a tubular vacuum chamber of few tenths of cm filled up with gaseous deuterium at very low pressure (0.7 Pa) and an erbium deuteride (ErD{sub 3}) screen. A lithium tantalate (LiTaO{sub 3}) pyroelectric crystal and a tungsten electrode are used to ionize and accelerate the gaseous deuterium with a minimum energy need. The collision of deuterium ions with the screen generates a maximum flow rate of about a thousand neutrons per second. Short paper. (J.S.)

  20. Status of intense permanent magnet proton source for China-accelerator driven sub-critical system Linac.

    Science.gov (United States)

    Wu, Q; Ma, H Y; Yang, Y; Sun, L T; Zhang, X Z; Zhang, Z M; Zhao, H Y; He, Y; Zhao, H W

    2016-02-01

    Two compact intense 2.45 GHz permanent magnet proton sources and their corresponding low energy beam transport (LEBT) system were developed successfully for China accelerator driven sub-critical system in 2014. Both the proton sources operate at 35 kV potential. The beams extracted from the ion source are transported by the LEBT, which is composed of two identical solenoids, to the 2.1 MeV Radio-Frequency Quadrupole (RFQ). In order to ensure the safety of the superconducting cavities during commissioning, an electrostatic-chopper has been designed and installed in the LEBT line that can chop the continuous wave beam into a pulsed one. The minimum width of the pulse is less than 10 μs and the fall/rise time of the chopper is about 20 ns. The performance of the proton source and the LEBT, such as beam current, beam profile, emittance and the impact to RFQ injection will be presented.

  1. Status of intense permanent magnet proton source for China-accelerator driven sub-critical system Linac

    Science.gov (United States)

    Wu, Q.; Ma, H. Y.; Yang, Y.; Sun, L. T.; Zhang, X. Z.; Zhang, Z. M.; Zhao, H. Y.; He, Y.; Zhao, H. W.

    2016-02-01

    Two compact intense 2.45 GHz permanent magnet proton sources and their corresponding low energy beam transport (LEBT) system were developed successfully for China accelerator driven sub-critical system in 2014. Both the proton sources operate at 35 kV potential. The beams extracted from the ion source are transported by the LEBT, which is composed of two identical solenoids, to the 2.1 MeV Radio-Frequency Quadrupole (RFQ). In order to ensure the safety of the superconducting cavities during commissioning, an electrostatic-chopper has been designed and installed in the LEBT line that can chop the continuous wave beam into a pulsed one. The minimum width of the pulse is less than 10 μs and the fall/rise time of the chopper is about 20 ns. The performance of the proton source and the LEBT, such as beam current, beam profile, emittance and the impact to RFQ injection will be presented.

  2. Status of intense permanent magnet proton source for China-accelerator driven sub-critical system Linac

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Q., E-mail: wuq@impcas.ac.cn; Ma, H. Y.; Yang, Y.; Sun, L. T.; Zhang, X. Z.; Zhang, Z. M.; Zhao, H. Y.; He, Y.; Zhao, H. W. [Institute of Modern Physics (IMP), Chinese Academy of Sciences, Lanzhou 730000 (China)

    2016-02-15

    Two compact intense 2.45 GHz permanent magnet proton sources and their corresponding low energy beam transport (LEBT) system were developed successfully for China accelerator driven sub-critical system in 2014. Both the proton sources operate at 35 kV potential. The beams extracted from the ion source are transported by the LEBT, which is composed of two identical solenoids, to the 2.1 MeV Radio-Frequency Quadrupole (RFQ). In order to ensure the safety of the superconducting cavities during commissioning, an electrostatic-chopper has been designed and installed in the LEBT line that can chop the continuous wave beam into a pulsed one. The minimum width of the pulse is less than 10 μs and the fall/rise time of the chopper is about 20 ns. The performance of the proton source and the LEBT, such as beam current, beam profile, emittance and the impact to RFQ injection will be presented.

  3. Timing reference generators and chopper controllers for neutron sources

    International Nuclear Information System (INIS)

    Nelson, R.; Merl, R.; Rose, C.

    2001-01-01

    Due to AC-power-grid frequency fluctuations, the designers for accelerator-based spallation-neutron facilities have worked to optimize the competing and contrasting demands of accelerator and neutron chopper performance. Powerful new simulation techniques have enabled the modeling of the timing systems that integrate chopper controllers and chopper hardware. For the first time, we are able to quantitatively access the tradeoffs between these two constraints and design or upgrade a facility to optimize total system performance. Thus, at LANSCE, we now operate multiple chopper systems and the accelerator as simple slaves to a single master-timing-reference generator. For the SNS we recommend a similar system that is somewhat less tightly coupled to the power grid. (author)

  4. Activation analysis with neutron generators using short-lived radionuclides

    International Nuclear Information System (INIS)

    Salma, I.

    1993-01-01

    The short half-life involves a number of important differences in production, transportation and measurement of radionuclides, and in counting statistics as compared with those in traditional activation analysis. Experiments were performed to investigate the analytical possibilities and prospective utilization of short-lived radionuclides produced by 14-MeV neutron irradiation. A rapid pneumatic transfer system for use with neutron generators was installed and applied for detecting radionuclides with a half-life from 300 ms to 30 s. The transport time for samples with a total mass of 1-4 g is between 130 and 160 ms for pressurized air of 0.1-0.4 MPa. 11 elements were studied by the conventional activation method using both a typical pneumatic transport system (run time 3 s) and the fast pneumatic transport facility. The effect of the cyclic activation technique on the elemental sensitivities was also investigated. (orig.)

  5. Recovery of spent high intensity neutron sources in Atalante Facility

    International Nuclear Information System (INIS)

    Bros, P.; Boyer Deslys, V.; Millet, A.; Solinhac, I.; Donnet, L.; Maillard, C.; Paillard, S.; Ranchoux, M.

    2005-01-01

    The Atalante facility is required by law to recover both neutron and gamma sources with activity levels exceeding 300 mCi. Most of the neutron sources consist of mixtures of alpha-emitters (238Pu, 239Pu, 241Am or 244Cm) and beryllium. Several processes now under consideration are based on routine chemical separation techniques (selective precipitation, extraction chromatography, ion exchange). The treatment produces an actinide oxide (which is used later for R and D studies) and solid beryllium nitrate, which is considered as a waste and transferred to a surface interim storage site if the overall activity of the package after 300 years is less than 50 MBq (ANDRA specifications). The Material Analysis and Metrology Laboratory of Atalante validate the residual alpha activity in the waste. The techniques used include alpha spectrometry and L-line X-ray fluorescence for alpha emitters, and plasma torch measurements (ICP-AES and ICP-MS) for beryllium analysis. Specific equipment for transport (B type cask), storage and treatment (hot shielded cells) are used for this activity. (Author)

  6. High Power CW Superconducting Linacs for EURISOL and XADS

    CERN Document Server

    Biarrotte, J L

    2004-01-01

    A multi-MW superconducting proton linac is proposed as the baseline solution for the EURISOL and the XADS driver accelerators. In the EURISOL project, which studies the design of the next-generation European ISOL facility, it is used to produce both neutron-deficient and neutron-rich exotic nuclei far from the valley of stability. In the PDS-XADS project, which aims to the demonstration of the feasibility of an ADS system for nuclear waste transmutation, it is used to produce the neutron flux required by the associated sub-critical reactor. In this paper, we report the main results and conclusions reached within these preliminary design studies. A special emphasis is given on the on-going and future R&D to be done to accomplish the demonstration of the full technology.

  7. High current induction linacs

    International Nuclear Information System (INIS)

    Barletta, W.; Faltens, A.; Henestroza, E.; Lee, E.

    1994-07-01

    Induction linacs are among the most powerful accelerators in existence. They have accelerated electron bunches of several kiloamperes, and are being investigated as drivers for heavy ion driven inertial confinement fusion (HIF), which requires peak beam currents of kiloamperes and average beam powers of some tens of megawatts. The requirement for waste transmutation with an 800 MeV proton or deuteron beam with an average current of 50 mA and an average power of 40 MW lies midway between the electron machines and the heavy ion machines in overall difficulty. Much of the technology and understanding of beam physics carries over from the previous machines to the new requirements. The induction linac allows use of a very large beam aperture, which may turn out to be crucial to reducing beam loss and machine activation from the beam halo. The major issues addressed here are transport of high intensity beams, availability of sources, efficiency of acceleration, and the state of the needed technology for the waste treatment application. Because of the transformer-like action of an induction core and the accompanying magnetizing current, induction linacs make the most economic sense and have the highest efficiencies with large beam currents. Based on present understanding of beam transport limits, induction core magnetizing current requirements, and pulse modulators, the efficiencies could be very high. The study of beam transport at high intensities has been the major activity of the HIF community. Beam transport and sources are limiting at low energies but are not significant constraints at the higher energies. As will be shown, the proton beams will be space-charge-dominated, for which the emittance has only a minor effect on the overall beam diameter but does determine the density falloff at the beam edge

  8. Neutron Generators Developed at LBNL for Homeland Security and Imaging Applications

    International Nuclear Information System (INIS)

    Reijonen, Jani

    2006-01-01

    The Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory has developed various types of advanced D-D (neutron energy 2.5 MeV), D-T (14 MeV) and T-T (0-9 MeV) neutron generators for wide range of applications. These applications include medical (Boron Neutron Capture Therapy), homeland security (Prompt Gamma Activation Analysis, Fast Neutron Activation Analysis and Pulsed Fast Neutron Transmission Spectroscopy) and planetary exploration with a sub-surface material characterization on Mars. These neutron generators utilize RF induction discharge to ionize the deuterium/tritium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. Four main neutron generator developments are discussed here: high neutron output co-axial neutron generator for BNCT applications, point neutron generator for security applications, compact and sub-compact axial neutron generator for elemental analysis applications. Current status of the neutron generator development with experimental data will be presented

  9. Compact Neutron Generators for Medical Home Land Security and Planetary Exploration

    International Nuclear Information System (INIS)

    Reijonen, J.

    2005-01-01

    The Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory has developed various types of advanced D-D (neutron energy 2.5 MeV), D-T (14 MeV) and T-T (0-9 MeV) neutron generators for wide range of applications. These applications include medical (Boron Neutron Capture Therapy), homeland security (Prompt Gamma Activation Analysis, Fast Neutron Activation Analysis and Pulsed Fast Neutron Transmission Spectroscopy) and planetary exploration with a sub-surface material characterization on Mars. These neutron generators utilize RF induction discharge to ionize the deuterium/tritium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. Four main neutron generator developments are discussed here: high neutron output co-axial neutron generator for BNCT applications, point neutron generator for security applications, compact and sub-compact axial neutron generator for elemental analysis applications. Current status of the neutron generator development with experimental data will be presented

  10. Neutron tomography of axially symmetric objects using 14 MeV neutrons from a portable neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, P., E-mail: peter.andersson@physics.uu.se; Andersson-Sunden, E.; Sjöstrand, H.; Jacobsson-Svärd, S. [Department of Physics and Astronomy, Division of Applied Nuclear Physics, Uppsala University, Lägerhyddsgatan 1, 751 20 Uppsala (Sweden)

    2014-08-01

    In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantage of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm{sup −1}, solid POM attenuation coefficient. The accuracy and precision is high enough to provide a useful

  11. Neutron tomography of axially symmetric objects using 14 MeV neutrons from a portable neutron generator.

    Science.gov (United States)

    Andersson, P; Andersson-Sunden, E; Sjöstrand, H; Jacobsson-Svärd, S

    2014-08-01

    In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantage of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm(-1), solid POM attenuation coefficient. The accuracy and precision is high enough to provide a useful

  12. Materials-based process tolerances for neutron generator encapsulation

    International Nuclear Information System (INIS)

    Berry, Ryan S.; Adolf, Douglas Brian; Stavig, Mark Edwin

    2007-01-01

    Variations in the neutron generator encapsulation process can affect functionality. However, instead of following the historical path in which the effects of process variations are assessed directly through functional tests, this study examines how material properties key to generator functionality correlate with process variations. The results of this type of investigation will be applicable to all generators and can provide insight on the most profitable paths to process and material improvements. Surprisingly, the results at this point imply that the process is quite robust, and many of the current process tolerances are perhaps overly restrictive. The good news lies in the fact that our current process ensures reproducible material properties. The bad new lies in the fact that it would be difficult to solve functional problems by changes in the process

  13. Materials-based process tolerances for neutron generator encapsulation.

    Energy Technology Data Exchange (ETDEWEB)

    Berry, Ryan S.; Adolf, Douglas Brian; Stavig, Mark Edwin

    2007-10-01

    Variations in the neutron generator encapsulation process can affect functionality. However, instead of following the historical path in which the effects of process variations are assessed directly through functional tests, this study examines how material properties key to generator functionality correlate with process variations. The results of this type of investigation will be applicable to all generators and can provide insight on the most profitable paths to process and material improvements. Surprisingly, the results at this point imply that the process is quite robust, and many of the current process tolerances are perhaps overly restrictive. The good news lies in the fact that our current process ensures reproducible material properties. The bad new lies in the fact that it would be difficult to solve functional problems by changes in the process.

  14. Electron cloud effects in intense, ion beam linacs theory and experimental planning for heavy-ion fusion

    International Nuclear Information System (INIS)

    Molvik, A.W.; Cohen, R.H.; Lund, S.M.; Bieniosek, F.M.; Lee, E.P.; Prost, L.R.; Seidl, P.A.; Vay, Jean-Luc

    2002-01-01

    Heavy-ion accelerators for HIF will operate at high aperture-fill factors with high beam current and long pulses. This will lead to beam ions impacting walls: liberating gas molecules and secondary electrons. Without special preparation a large fractional electron population ((ge)1%) is predicted in the High-Current Experiment (HCX), but wall conditioning and other mitigation techniques should result in substantial reduction. Theory and particle-in-cell simulations suggest that electrons, from ionization of residual and desorbed gas and secondary electrons from vacuum walls, will be radially trapped in the ∼4 kV ion beam potential. Trapped electrons can modify the beam space charge, vacuum pressure, ion transport dynamics, and halo generation, and can potentially cause ion-electron instabilities. Within quadrupole (and dipole) magnets, the longitudinal electron flow is limited to drift velocities (E x B and (del)B) and the electron density can vary azimuthally, radially, and longitudinally. These variations can cause centroid misalignment, emittance growth and halo growth. Diagnostics are being developed to measure the energy and flux of electrons and gas evolved from walls, and the net charge and gas density within magnetic quadrupoles, as well as the their effect on the ion beam

  15. The FAIR proton linac

    International Nuclear Information System (INIS)

    Kester, O.

    2015-01-01

    FAIR - the Facility for Antiproton and Ion Research in Europe - constructed at GSI in Darmstadt comprises an international centre of heavy ion accelerators that will drive heavy ion and antimatter research. FAIR will provide worldwide unique accelerator and experimental facilities, allowing a large variety of fore-front research in physics and applied science. FAIR will deliver antiproton and ion beams of unprecedented intensities and qualities. The main part of the FAIR facility is a sophisticated accelerator system, which delivers beams to different experiments of the FAIR experimental collaborations - APPA, NuSTAR, CBM and PANDA - in parallel. Modern H-type cavities offer highest shunt impedances of resonant structures of heavy ion linacs at low beam energies < 20 MeV/u and enable the acceleration of intense proton and ion beams. One example is the interdigital H-type structure. The crossed-bar H-cavities extend these properties to high energies even beyond 100 MeV/u. Compared to conventional Alvarez cavities, these crossed-bar (CH) cavities feature much higher shunt impedance at low energies. The design of the proton linac is based on those cavities

  16. Prospects for accelerator neutron sources for large volume minerals analysis

    International Nuclear Information System (INIS)

    Clayton, C.G.; Spackman, R.

    1988-01-01

    The electron Linac can be regarded as a practical source of thermal neutrons for activation analysis of large volume mineral samples. With a suitable target and moderator, a neutron flux of about 10 10 n/cm/s over 2-3 kg of rock can be generated. The proton Linac gives the possibility of a high neutron yield (> 10 12 n/s) of fast neutrons at selected energies. For the electron Linac, targets of W-U and W-Be are discussed. The advantages and limitations of the system are demonstrated for the analysis of gold in rocks and ores and for platinum in chromitite. These elements were selected as they are most likely to justify an accelerator installation at the present time. Errors due to self shielding in gold particles for thermal neutrons are discussed. The proton Linac is considered for neutrons generated from a lithium target through the 7 Li(p, n) 7 Be reaction. The analysis of gold by fast neutron activation is considered. This approach avoids particle self-absorption and, by appropriate proton energy selection, avoids potentially dominating interfering reactions. The analysis of 235 U in the presence of 238 U and 232 Th is also considered. (author)

  17. Monte Carlo Simulation on Compensated Neutron Porosity Logging in LWD With D-T Pulsed Neutron Generator

    International Nuclear Information System (INIS)

    Zhang Feng; Hou Shuang; Jin Xiuyun

    2010-01-01

    The process of neutron interaction induced by D-T pulsed neutron generator and 241 Am-Be source was simulated by using Monte Carlo method. It is concluded that the thermal neutron count descend exponentially as the spacing increasing. The smaller porosity was, the smaller the differences between the two sources were. When the porosity reached 40%, the ratio of thermal neutron count generated by D-T pulsed neutron source was much larger than that generated by 241 Am-Be neutron source, and its distribution range was wider. The near spacing selected was 20-30 cm, and that of far spacing was about 60-70 cm. The detection depth by using D-T pulsed neutron source was almost unchanged under condition of the same sapcing, and the sensitivity of measurement to the formation porosity decreases. The results showed that it can not only guarantee the statistic of count, but also improve detection sensitivity and depth at the same time of increasing spacing. Therefore, 241 Am-Be neutron source can be replaced by D-T neutron tube in LWD tool. (authors)

  18. Neutron activation analysis of zinc in forages used in intensive dairy cattle production systems

    International Nuclear Information System (INIS)

    Armelin, M.J.A.; Piasentin, R.M.; Primavesi, O.

    2002-01-01

    Instrumental neutron activation analysis (INAA) was applied for the determination of Zn concentration in the main tropical grass forages used in intensive dairy cattle production systems, in Brazil. Smaller Zn concentration could be verified in the rainy period. Comparison of results obtained in these analyses of forages dry matter with daily requirements pointed towards deficiency of Zn in the forages. (author)

  19. Effect of covalent bonding on magnetism and the missing neutron intensity in copper oxide compounds

    NARCIS (Netherlands)

    Walters, A.C.; Perring, T.G.; Caux, J.S.; Savici, A.T.; Gu, G.D.; Lee, C.C.; Ku, W.; Zaliznyak, I.A.

    2009-01-01

    Theories involving highly energetic spin fluctuations are among the leading contenders for explaining high-temperature superconductivity in the cuprates(1). These theories could be tested by inelastic neutron scattering ( INS), as a change in the magnetic scattering intensity that marks the entry

  20. Computer generated holography with intensity-graded patterns

    Directory of Open Access Journals (Sweden)

    Rossella Conti

    2016-10-01

    Full Text Available Computer Generated Holography achieves patterned illumination at the sample plane through phase modulation of the laser beam at the objective back aperture. This is obtained by using liquid crystal-based spatial light modulators (LC-SLMs, which modulate the spatial phase of the incident laser beam. A variety of algorithms are employed to calculate the phase modulation masks addressed to the LC-SLM. These algorithms range from simple gratings-and-lenses to generate multiple diffraction-limited spots, to iterative Fourier-transform algorithms capable of generating arbitrary illumination shapes perfectly tailored on the base of the target contour. Applications for holographic light patterning include multi-trap optical tweezers, patterned voltage imaging and optical control of neuronal excitation using uncaging or optogenetics. These past implementations of computer generated holography used binary input profile to generate binary light distribution at the sample plane. Here we demonstrate that using graded input sources, enables generating intensity graded light patterns and extend the range of application of holographic light illumination. At first, we use intensity-graded holograms to compensate for LC-SLM position dependent diffraction efficiency or sample fluorescence inhomogeneity. Finally we show that intensity-graded holography can be used to equalize photo evoked currents from cells expressing different level of chanelrhodopsin2 (ChR2, one of the most commonly used optogenetics light gated channels, taking into account the non-linear dependence of channel opening on incident light.

  1. Generation of intense high-order vortex harmonics.

    Science.gov (United States)

    Zhang, Xiaomei; Shen, Baifei; Shi, Yin; Wang, Xiaofeng; Zhang, Lingang; Wang, Wenpeng; Xu, Jiancai; Yi, Longqiong; Xu, Zhizhan

    2015-05-01

    This Letter presents for the first time a scheme to generate intense high-order optical vortices that carry orbital angular momentum in the extreme ultraviolet region based on relativistic harmonics from the surface of a solid target. In the three-dimensional particle-in-cell simulation, the high-order harmonics of the high-order vortex mode is generated in both reflected and transmitted light beams when a linearly polarized Laguerre-Gaussian laser pulse impinges on a solid foil. The azimuthal mode of the harmonics scales with its order. The intensity of the high-order vortex harmonics is close to the relativistic region, with the pulse duration down to attosecond scale. The obtained intense vortex beam possesses the combined properties of fine transversal structure due to the high-order mode and the fine longitudinal structure due to the short wavelength of the high-order harmonics. In addition to the application in high-resolution detection in both spatial and temporal scales, it also presents new opportunities in the intense vortex required fields, such as the inner shell ionization process and high energy twisted photons generation by Thomson scattering of such an intense vortex beam off relativistic electrons.

  2. Intense Pulsed Neutron Source progress report for 1991

    International Nuclear Information System (INIS)

    1991-01-01

    The IPNS Progress Report 10th Anniversary Edition is being published in recognition of the first ten years of successful IPNS operation. To emphasize the significance of this milestone, we wanted this report to stand apart from the previous IPNS Progress Reports, and the best way to do this, we thought, was to make the design and organization of the report significantly different. In their articles, authors were asked to emphasize not only advances made since IPNS began operating but also the groundwork that was laid at its predecessor facilities - Argonne's ZING-P and ZING-P' prototype pulsed neutron sources and CP-5 reactor. Each article stands as a separate chapter in the report, since each represents a particular instrument or class of instruments, system, technique, or area of research. In some cases, contributions were similar to review articles in scientific journals, complete with extensive lists of references. Ten-year cumulative lists of members of IPNS committees and of scientists who have visited or done experiments at IPNS were assembled. A list of published and ''in press'' articles in journals, books, and conference proceedings, resulting from work done at IPNS during the past ten years, was compiled. And archival photographs of people and activities during the ten-year history of IPNS were located and were used liberally throughout the report. The titles of the chapters in this report are: accelerator; computer; radiation effects; powder; stress; single crystal; superconductivity; amorphous; small angle; reflection; quasielastic; inelastic; inelastic magnetic; deep inelastic; user program; the future; and publications

  3. Intense Pulsed Neutron Source progress report for 1991

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    The IPNS Progress Report 10th Anniversary Edition is being published in recognition of the first ten years of successful IPNS operation. To emphasize the significance of this milestone, we wanted this report to stand apart from the previous IPNS Progress Reports, and the best way to do this, we thought, was to make the design and organization of the report significantly different. In their articles, authors were asked to emphasize not only advances made since IPNS began operating but also the groundwork that was laid at its predecessor facilities - Argonne`s ZING-P and ZING-P` prototype pulsed neutron sources and CP-5 reactor. Each article stands as a separate chapter in the report, since each represents a particular instrument or class of instruments, system, technique, or area of research. In some cases, contributions were similar to review articles in scientific journals, complete with extensive lists of references. Ten-year cumulative lists of members of IPNS committees and of scientists who have visited or done experiments at IPNS were assembled. A list of published and ``in press`` articles in journals, books, and conference proceedings, resulting from work done at IPNS during the past ten years, was compiled. And archival photographs of people and activities during the ten-year history of IPNS were located and were used liberally throughout the report. The titles of the chapters in this report are: accelerator; computer; radiation effects; powder; stress; single crystal; superconductivity; amorphous; small angle; reflection; quasielastic; inelastic; inelastic magnetic; deep inelastic; user program; the future; and publications.

  4. Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion

    Science.gov (United States)

    Ren, G.; Yan, J.; Liu, J.; Lan, K.; Chen, Y. H.; Huo, W. Y.; Fan, Z.; Zhang, X.; Zheng, J.; Chen, Z.; Jiang, W.; Chen, L.; Tang, Q.; Yuan, Z.; Wang, F.; Jiang, S.; Ding, Y.; Zhang, W.; He, X. T.

    2017-04-01

    We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 1 014- 1 015 W /cm2 intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Yn to be related to the laser energy EL, the hohlraum radius Rh, and the pulse duration τ through a scaling law of Yn∝(EL/Rh1.2τ0.2 )2.5. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

  5. Neutron source investigations in support of the cross section program at the Argonne Fast-Neutron Generator

    International Nuclear Information System (INIS)

    Meadows, J.W.; Smith, D.L.

    1980-05-01

    Experimental methods related to the production of neutrons for cross section studies at the Argonne Fast-Neutron Generator are reviewed. Target assemblies commonly employed in these measurements are described, and some of the relevant physical properties of the neutron source reactions are discussed. Various measurements have been performed to ascertain knowledge about these source reaction that is required for cross section data analysis purposes. Some results from these studies are presented, and a few specific examples of neutron-source-related corrections to cross section data are provided. 16 figures, 3 tables

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

    Science.gov (United States)

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

    2015-12-01

    A free surface liquid-lithium jet target is operating routinely at Soreq Applied Research Accelerator Facility (SARAF), bombarded with a ~1.91 MeV, ~1.2 mA continuous-wave narrow proton beam. The experiments demonstrate the liquid lithium target (LiLiT) capability to constitute an intense source of epithermal neutrons, for Accelerator based Boron Neutron Capture Therapy (BNCT). The target dissipates extremely high ion beam power densities (>3 kW/cm(2), >0.5 MW/cm(3)) for long periods of time, while maintaining stable conditions and localized residual activity. LiLiT generates ~3×10(10) n/s, which is more than one order of magnitude larger than conventional (7)Li(p,n)-based near threshold neutron sources. A shield and moderator assembly for BNCT, with LiLiT irradiated with protons at 1.91 MeV, was designed based on Monte Carlo (MCNP) simulations of BNCT-doses produced in a phantom. According to these simulations it was found that a ~15 mA near threshold proton current will apply the therapeutic doses in ~1h treatment duration. According to our present results, such high current beams can be dissipated in a liquid-lithium target, hence the target design is readily applicable for accelerator-based BNCT. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Compact D-D/D-T neutron generators and their applications

    Energy Technology Data Exchange (ETDEWEB)

    Lou, Tak Pui [Univ. of California, Berkeley, CA (United States)

    2003-01-01

    Neutron generators based on the 2H(d,n)3He and 3H(d,n)4He fusion reactions are the most commonly available neutron sources. The applications of current commercial neutron generators are often limited by their low neutron yield and their short operational lifetime. A new generation of D-D/D-T fusion-based neutron generators has been designed at Lawrence Berkeley National Laboratory (LBNL) by using high current ion beams hitting on a self-loading target that has a large surface area to dissipate the heat load. This thesis describes the rationale behind the new designs and their potential applications. A survey of other neutron sources is presented to show their advantages and disadvantages compared to the fusion-based neutron generator. A prototype neutron facility was built at LBNL to test these neutron generators. High current ion beams were extracted from an RF-driven ion source to produce neutrons. With an average deuteron beam current of 24 mA and an energy of 100 keV, a neutron yield of >109 n/s has been obtained with a D-D coaxial neutron source. Several potential applications were investigated by using computer simulations. The computer code used for simulations and the variance reduction techniques employed were discussed. A study was carried out to determine the neutron flux and resolution of a D-T neutron source in thermal neutron scattering applications for condensed matter experiments. An error analysis was performed to validate the scheme used to predict the resolution. With a D-T neutron yield of 1014 n/s, the thermal neutron flux at the sample was predicted to be 7.3 x 105 n/cm2s. It was found that the resolution of cold neutrons was better than that of thermal neutrons when the duty factor is high. This neutron generator could be efficiently used for research and educational purposes at universities. Additional applications studied were positron production and

  8. Compact D-D/D-T neutron generators and their applications

    International Nuclear Information System (INIS)

    Lou, Tak Pui

    2003-01-01

    Neutron generators based on the 2 H(d,n) 3 He and 3 H(d,n) 4 He fusion reactions are the most commonly available neutron sources. The applications of current commercial neutron generators are often limited by their low neutron yield and their short operational lifetime. A new generation of D-D/D-T fusion-based neutron generators has been designed at Lawrence Berkeley National Laboratory (LBNL) by using high current ion beams hitting on a self-loading target that has a large surface area to dissipate the heat load. This thesis describes the rationale behind the new designs and their potential applications. A survey of other neutron sources is presented to show their advantages and disadvantages compared to the fusion-based neutron generator. A prototype neutron facility was built at LBNL to test these neutron generators. High current ion beams were extracted from an RF-driven ion source to produce neutrons. With an average deuteron beam current of 24 mA and an energy of 100 keV, a neutron yield of >10 9 n/s has been obtained with a D-D coaxial neutron source. Several potential applications were investigated by using computer simulations. The computer code used for simulations and the variance reduction techniques employed were discussed. A study was carried out to determine the neutron flux and resolution of a D-T neutron source in thermal neutron scattering applications for condensed matter experiments. An error analysis was performed to validate the scheme used to predict the resolution. With a D-T neutron yield of 10 14 n/s, the thermal neutron flux at the sample was predicted to be 7.3 x 10 5 n/cm 2 s. It was found that the resolution of cold neutrons was better than that of thermal neutrons when the duty factor is high. This neutron generator could be efficiently used for research and educational purposes at universities. Additional applications studied were positron production and Boron Neutron Capture Therapy (BNCT). The neutron flux required for positron

  9. Bipolar pulse generator for intense pulsed ion beam accelerator

    International Nuclear Information System (INIS)

    Ito, H.; Igawa, K.; Kitamura, I.; Masugata, K.

    2007-01-01

    A new type of pulsed ion beam accelerator named ''bipolar pulse accelerator'' (BPA) has been proposed in order to improve the purity of intense pulsed ion beams. To confirm the principle of the BPA, we developed a bipolar pulse generator for the bipolar pulse experiment, which consists of a Marx generator and a pulse forming line (PFL) with a rail gap switch on its end. In this article, we report the first experimental result of the bipolar pulse and evaluate the electrical characteristics of the bipolar pulse generator. When the bipolar pulse generator was operated at 70% of the full charge condition of the PFL, the bipolar pulse with the first (-138 kV, 72 ns) and the second pulse (+130 kV, 70 ns) was successfully obtained. The evaluation of the electrical characteristics indicates that the developed generator can produce the bipolar pulse with fast rise time and sharp reversing time

  10. Performance of a tagged neutron inspection system (TNIS) based on portable sealed generators

    International Nuclear Information System (INIS)

    Nebbia, G.; Pesente, S.; Lunardon, M.; Viesti, G.; LeTourneur, P.; Heuveline, F.; Mangeard, M.; Tcheng, C.

    2004-01-01

    A portable sealed neutron generator has been modified to produce 14MeV tagged neutron beams with an embedded YAP:Ce scintillation detector. The system has been tested by detecting the coincident gamma-rays produced in the irradiation of a graphite sample by means of a standard NaI(Tl) scintillator. Time resolution of about δt=4-5ns (FWHM) has been measured. The sealed neutron tube has been operated up to 10 7 neutron/s. Possible applications in non-destructive assays and future developments of the Tagged Neutron Inspection System concept are discussed

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

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  12. Optic fibber data acquisition and transmission system dedicated to a neutron generator

    International Nuclear Information System (INIS)

    Ledo Pereda, Luis Miguel; Vergara Limon, Sergio; Arteche Diaz, Raul

    2009-01-01

    Hereby, are presented the design, construction and application of a virtual data acquisition system based on the usage of microcontrollers, optic fibber, and PC. System is aimed to the reestablishment of the communication between the basic modules of a Neutron Generator. The work shows, how the original interface design is upgraded by the automation of the data acquisition, on the Neutron Generator exploitation parameters. The PC usage is being introduced in the Neutron Generator and the precedent is established for further subsystem

  13. The upgrade of intense pulsed neutron source (IPNS) through the change of coolant and reflector

    CERN Document Server

    Baek, I C; Iverson, E B

    2002-01-01

    The current intense pulsed neutron source (IPNS) depleted uranium target is cooled by light water. The inner reflector material is graphite and the outer reflector material is beryllium. The presence of H sub 2 O in the target moderates neutrons and leads to a higher absorption loss in the target than is necessary. D sub 2 O coolant in the small quantities required minimizes this effect. We have studied the possible improvement in IPNS beam fluxes that would result from changing the coolant from H sub 2 O to D sub 2 O and the inner reflector from graphite to beryllium. Neutron intensities were calculated for directions normal to the viewed surface of each moderator for four different cases of combinations of target coolant and reflector materials. The simulations reported here were performed using the MCNPX (version 2.1.5) computer program. Our results show that substantial gains in neutron beam intensities can be achieved by appropriate combination of target coolant and reflector materials. The combination o...

  14. Optimization of beam shaping assembly based on D-T neutron generator and dose evaluation for BNCT

    Science.gov (United States)

    Naeem, Hamza; Chen, Chaobin; Zheng, Huaqing; Song, Jing

    2017-04-01

    The feasibility of developing an epithermal neutron beam for a boron neutron capture therapy (BNCT) facility based on a high intensity D-T fusion neutron generator (HINEG) and using the Monte Carlo code SuperMC (Super Monte Carlo simulation program for nuclear and radiation process) is proposed in this study. The Monte Carlo code SuperMC is used to determine and optimize the final configuration of the beam shaping assembly (BSA). The optimal BSA design in a cylindrical geometry which consists of a natural uranium sphere (14 cm) as a neutron multiplier, AlF3 and TiF3 as moderators (20 cm each), Cd (1 mm) as a thermal neutron filter, Bi (5 cm) as a gamma shield, and Pb as a reflector and collimator to guide neutrons towards the exit window. The epithermal neutron beam flux of the proposed model is 5.73 × 109 n/cm2s, and other dosimetric parameters for the BNCT reported by IAEA-TECDOC-1223 have been verified. The phantom dose analysis shows that the designed BSA is accurate, efficient and suitable for BNCT applications. Thus, the Monte Carlo code SuperMC is concluded to be capable of simulating the BSA and the dose calculation for BNCT, and high epithermal flux can be achieved using proposed BSA.

  15. Neutron generators with size scalability, ease of fabrication and multiple ion source functionalities

    Science.gov (United States)

    Elizondo-Decanini, Juan M

    2014-11-18

    A neutron generator is provided with a flat, rectilinear geometry and surface mounted metallizations. This construction provides scalability and ease of fabrication, and permits multiple ion source functionalities.

  16. Generation of neutron scattering cross sections for silicon dioxide

    International Nuclear Information System (INIS)

    Ramos, R; Marquez Damian, J.I; Granada, J.R.; Cantargi, F

    2009-01-01

    A set of neutron scattering cross sections for silicon and oxygen bound in silicon dioxide were generated and validated. The cross sections were generated in the ACE format for MCNP using the nuclear data processing system NJOY, and the validation was done with published experimental data. This cross section library was applied to the calculation of five critical configurations published in the benchmark Critical Experiments with Heterogeneous Compositions of Highly Enriched Uranium, Silicon Dioxide and Polyethylene. The original calculations did not use the thermal scattering libraries generated in this work and presented significant differences with the experimental results. For this reason, the newly generated library was added to the input and the multiplication factor for each configuration was recomputed. The utilization of the thermal scattering libraries did not result in an improvement of the computational results. Based on this we conclude that integral experiments to validate this type of thermal cross sections need to be designed with a higher influence of thermal scattering in the measured result, and the experiments have to be performed under more controlled conditions. [es

  17. Tritium contamination and monitoring at Frascati Neutron Generator

    Energy Technology Data Exchange (ETDEWEB)

    Lucci, F.; Sandri, S.; Ianni, A. [ENEA, Frascati (Italy). Dipartimento Ambiente; Vasselli, R. [ANPA, Roma (Italy); Pillon, M.; Bettinali, L. [ENEA, Frascati (Italy). Dipartimento Energia

    1994-11-01

    The Frascati Neutron Generator (FGN) is a specialised 300 keV, 3 mA direct electrostatic deuteron accelerator which produces about 5-10{sup 1}1 14 MeV neutrons per second by D-T reactions on a tritium-titanium fixed target. This paper concerns the tritium contamination control and monitoring aspects after some months of testing and a preliminary period of operation of the plant. The tritium monitoring system is composed of both on-line and off-line devices to control the tritium concentration in the atmosphere measured from different parts of the plant: vacuum exhaust clean up (VECU) system, stack, etc. The on-line devices are three flux monitors, that sample continuosly the air from up to eight different points in the plant. The passive sampling system is designed to select the chemical form of tritium and to collect respectively HTO and HT in two different cartridges filled with an appropriate drying material. The response of the on-line tritium monitor system are exposed and discussed: some measurements performed with atmosphere dehumidifying apparatus of this system are described and the relevant results are analysed.

  18. Tritium contamination and monitoring at Frascati Neutron Generator

    International Nuclear Information System (INIS)

    Lucci, F.; Sandri, S.; Ianni, A.; Pillon, M.; Bettinali, L.

    1994-11-01

    The Frascati Neutron Generator (FGN) is a specialised 300 keV, 3 mA direct electrostatic deuteron accelerator which produces about 5-10 1 1 14 MeV neutrons per second by D-T reactions on a tritium-titanium fixed target. This paper concerns the tritium contamination control and monitoring aspects after some months of testing and a preliminary period of operation of the plant. The tritium monitoring system is composed of both on-line and off-line devices to control the tritium concentration in the atmosphere measured from different parts of the plant: vacuum exhaust clean up (VECU) system, stack, etc. The on-line devices are three flux monitors, that sample continuosly the air from up to eight different points in the plant. The passive sampling system is designed to select the chemical form of tritium and to collect respectively HTO and HT in two different cartridges filled with an appropriate drying material. The response of the on-line tritium monitor system are exposed and discussed: some measurements performed with atmosphere dehumidifying apparatus of this system are described and the relevant results are analysed

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

    International Nuclear Information System (INIS)

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

    1987-01-01

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

  20. Design of auto-control high-voltage control system of pulsed neutron generator

    International Nuclear Information System (INIS)

    Lv Juntao

    2008-01-01

    It is difficult to produce multiple anode controlling time sequences under different logging mode for the high-voltage control system of the conventional pulsed neutron generator. It is also difficult realize sequential control among anode high-voltage, filament power supply and target voltage to make neutron yield stable. To these problems, an auto-control high-voltage system of neutron pulsed generator was designed. It not only can achieve anode high-voltage double blast time sequences, which can measure multiple neutron blast time sequences such as Σ, activated spectrum, etc. under inelastic scattering mode, but also can realize neutron generator real-time measurement of multi-state parameters and auto-control such as target voltage pulse width modulation (PWM), filament current, anode current, etc., there by it can produce stable neutron yield and realize stable and accurate measurement of the pulsed neutron full spectral loging tool. (authors)

  1. Calibration Of A 14 MeV Neutron Generator With Reference To NBS-1

    International Nuclear Information System (INIS)

    Heimbach, Craig R.

    2011-01-01

    NBS-1 is the US national neutron reference source. It has a neutron emission rate (June 1961) of 1.257x10 6 n/s 1,2,3 with an uncertainty of 0.85%(k = 1). Neutron emission-rate calibrations performed at the National Institute of Standards and Technology (NIST) are made in comparison to this source, either directly or indirectly. To calibrate a commercial 14 MeV neutron generator, NIST performed a set of comparison measurements to evaluate the neutron output relative to NBS-1. The neutron output of the generator was determined with an uncertainty of about 7%(k = 1). The 15-hour half-life of one of the reactions used also makes possible off-site measurements. Consideration is given to similar calibrations for a 2.5 MeV neutron generator.

  2. Short wavelength FELs using the SLAC linac

    International Nuclear Information System (INIS)

    Winick, H.; Bane, K.; Boyce, R.

    1993-08-01

    Recent technological developments have opened the possibility to construct a device which we call a Linac Coherent Light Source (LCLS); a fourth generation light source, with brightness, coherence, and peak power far exceeding other sources. Operating on the principle of the free electron laser (FEL), the LCLS would extend the range of FEL operation to much aborter wavelength than the 240 mn that has so far been reached. We report the results of studies of the use of the SLAC linac to drive an LCLS at wavelengths from about 3-100 nm initially and possibly even shorter wavelengths in the future. Lasing would be achieved in a single pass of a low emittance, high peak current, high energy electron beam through a long undulator. Most present FELs use an optical cavity to build up the intensity of the light to achieve lasing action in a low gain oscillator configuration. By eliminating the optical cavity, which is difficult to make at short wavelengths, laser action can be extended to shorter wavelengths by Self-Amplified-Spontaneous-Emission (SASE), or by harmonic generation from a longer wavelength seed laser. Short wavelength, single pass lasers have been extensively studied at several laboratories and at recent workshops

  3. Design Concept of a Seal-off Type 14 MeV Neutron Generator of 10''1''1n/s Range

    Energy Technology Data Exchange (ETDEWEB)

    In, S. R.; Oh, B. H. [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    The total neutron fluence during the life time is expected to be around 10MW·yr/m''2 which may cause a damage of -100 dpa in materials. To estimate the adaptability of candidate materials in a few years, a 14MeV neutron source with a flux level of 3 - 5 x 10''1''8 n/s·m''2, which is the goal of the IFMIF facility costing more than ¤1000M, is necessitated. The problem in making an intense neutron generator of beam target type is really not on the neutron production rate, but on the huge heat generated in the target, because the fusion power is only one of thousands of beam power exerted on the target. We have a plan to develop neutron generators step by step from a 10''8 n/s level. The final goal is establishing a 14MeV neutron irradiation facility at 10''1''4 intensity level.. Up to the 10''1''0 n/s level, there occurs basically no critical thermal problem, because beam power density is in the range of tens W/cm''2. The neutron generator designed in a sealed-off type because of tritium safety is mainly composed of an ion source, target, reaction chamber, and getter pump.. The major design concepts for the neutron generator with the neutron production rate of 10''1''1 n/s range were presented. The specifications of the ion source, target and getter have been determined for attaining the goal of the neutron generation rate.

  4. Production of slow-positron beams with an electron linac

    International Nuclear Information System (INIS)

    Howell, R.H.; Alvarez, R.A.; Stanek, M.

    1982-01-01

    Intense, pulsed beams of low-energy positrons have been produced by a high-energy beam from an electron linac. The production efficiency for low-energy positrons has been determined for electrons with 60 to 120 MeV energy, low-energy positron beams from a linac can be of much higher intensity than those beams currently derived from radioactive sources

  5. CIAE 600 kV ns pulse neutron generator

    International Nuclear Information System (INIS)

    Shen Guanren; Guan Xialing; Chen Hongtao

    2001-01-01

    The overall composition of CIAE 600 kV ns Pulse Neutron Generator (CPNG) are introduced, and its characteristic, main technological performance and application were also given. CPNG consists of high voltage power supply with highest output voltage 600 kV, direct current 15 mA, stability and ripple ≤0.1%, 2214 mm x 1604 mm x 1504 mm stainless steel high voltage electrode, built in head equipment uniform field accelerating tube, ns pulsed installation, turbomolecular vacuum pump system and drift pipes at 0 degree and 45 degree. Its characteristics are: (1) high current beam; (2) high current beam ns pulsed installation made use of low energy for chopper and high energy for buncher; (3) compactly laid out and simple in structure

  6. Major projects for the use of high power linacs

    International Nuclear Information System (INIS)

    Prome, M.

    1996-01-01

    A review of the major projects for high power linacs is given. The field covers the projects aiming at the transmutation of nuclear waste or the production of tritium, as well as the production of neutrons for hybrid reactors or basic research with neutron sources. The technologies which arc common to all the projects are discussed. Comments are made on the technical difficulties encountered by all the projects, and the special problems of the pulsed linacs are mentioned. Elements for a comparison of normal conducting linacs versus superconducting ones are given. Finally the technical developments being made in various laboratories are reviewed. (author)

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

    Science.gov (United States)

    Parkin, Don M.; Dudey, Norman D.

    1976-01-01

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

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

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  9. Design status of an intense 14 MeV neutron source for cancer therapy

    CERN Document Server

    Yao, Z E; Cheng, S W; Jia, W B

    2002-01-01

    Design and development of an intense 14 MeV neutron source for cancer therapy is in progress at the Institute of Nuclear Research of Lanzhou University. The neutrons from the T(d,n) sup 4 He reaction are produced by bombarding a rotating titanium tritide target with a 40 mA deuteron beam at 600 keV. The designed neutron yield is 8x10 sup 1 sup 2 n/s and the maximum dose rate at a 100 cm source-to-skin distance is 25 cGy/min. The HV terminal, accelerating column and HV power supply are enclosed inside a stainless steel pressure vessel containing 6 atm SF sub 6 gas to provide the electrical insulation.

  10. Measurement of the neutron intensity data using the HANARO four circle diffractometer

    International Nuclear Information System (INIS)

    Lee, Jin Ho; Lee, Chang Hee; Seong, Baek Seok; Lee, Jeong Soo; Shim, Hae Seop; Hong, Kwang Pyo; Song, Su Ho; Suh, Il Hwan

    1999-04-01

    As the four circle diffractometer(FCD) has been set up in HANARO, it has become possible to study single crystal structures by means of the neutron diffraction. By introducing the constitution and characteristics of FCD, it has been shown that the feature of neutron diffraction experiment are different from that of X-ray or electronic beam. Besides we have explained the processes of determining experimental information in order to acquire intensity data and constructed the experimental system based on geometry of the FCD. As the computer programme performing all experimental processes automatically has been installed and the accuracy of experimental processes were confirmed by KCl single crystal experiment, the original experimental system for single crystal experiments and analyses by the neutron diffraction method using FCD has been established. (Author). 12 refs., 2 tabs., 11 figs

  11. Multipurpose intense 14 MeV neutron source at Bratislava: Design study

    International Nuclear Information System (INIS)

    Pivarc, J.; Hlavac, S.; Kral, J.; Oblozinsky, P.; Ribansky, I.; Turzo, I.

    1980-05-01

    The present state of design of the multipurpose intense 14 MeV neutron source based on a D + ion beam and a metal tritide target is reported. It is essentially a 300 keV electrostatic air insulated accelerator capable to accelerate a deuterium ion beam up to 10 mA. With such a beam and a beam spot of 1 cm 2 , a neutron yield typically 10 12 n/s and a useful target lifetime of around 10 h are expected. Various users requirements are met by means of three beam lines: an intense, low current dc and a low current fast pulsed. The key components of the intense source section are the rotating target and the ion source. The rotating target is proposed, with respect of the heat dissipation and the removal of 3 kW/cm 2 , in continuous operation. A rotation speed up to 1100 rpm is considered. The ion source should deliver about 0.5 kW of extracted D + ion beam power. A duoplasmatron source with an electrostatic beam focusing system has been selected. Low current sections of the neutron source may operate with a high frequency ion source as well. The dc section for maximum yields around 10 10 n/s is designed with special regard to beam monitoring. The fast pulsed section should produce up to 1 ns compressible pulsed D + ion beam on a target spot with 5 MHz repetition rate. The report includes information about other components of the neutron source as a high voltage power supply, a vacuum system, beam transport, a diagnostic and control system and basic information about neutron source cells and radiation protection. (author)

  12. Determination of the emission rate for the 14 MeV neutron generator with the use of radio-yttrium

    OpenAIRE

    Laszynska Ewa; Jednorog Slawomir; Ziolkowski Adam; Gierlik Michal; Rzadkiewicz Jacek

    2015-01-01

    The neutron emission rate is a crucial parameter for most of the radiation sources that emit neutrons. In the case of large fusion devices the determination of this parameter is necessary for a proper assessment of the power release and the prediction for the neutron budget. The 14 MeV neutron generator will be used for calibration of neutron diagnostics at JET and ITER facilities. The stability of the neutron generator working parameters like emission and angular homogeneity affects the accu...

  13. D-T neutron generator development for cancer therapy. 1980 annual progress report

    International Nuclear Information System (INIS)

    Bacon, F.M.; Walko, R.J.; Bickes, R.W. Jr.; Cowgill, D.F.; Riedel, A.A.; O'Hagan, J.B.

    1980-05-01

    This report summarizes the work completed during the first year of a two-year grant by NCI/HEW to investigate the feasibility of developing a D-T neutron generator for use in cancer therapy. Experiments have continued on the Target Test Facility (TTF) developed during a previous grant to investigate high-temperature metal hydrides for use as target materials. The high voltage reliability of the TTF has been improved so that 200 kV, 200 mA operation is now routine. In recent target tests, the D-D neutron production rate was measured to be > 1 x 10 11 /s, a rate that corresponds to a D-T neutron production rate of > 1 x 10 13 /s - the desired rate for use in cancer therapy. Deuterium concentration depth profiles in the target, measured during intense ion beam bombardment, show that deuterium is depleted near the surface of the target due to impurities implanted by the ion beam. Recent modifications of the duopigatron ion source to reduce secondary electron damage to the electrodes also improved the ion source efficiency by about 40%. An ultra high vacuum version of the TTF is now being constructed to determine if improved vacuum conditions will reduce ion source impurities to a sufficiently low level that the deuterium near the surface of the target is not depleted. Testing will begin in June 1980

  14. Accelerator-based intense neutron source for materials R ampersand D

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1990-01-01

    Accelerator-based neutron sources for R ampersand D of materials in nuclear energy systems, including fusion reactors, can provide sufficient neutron flux, flux-volume, fluence and other attractive features for many aspects of materials research. The neutron spectrum produced from the D-Li reaction has been judged useful for many basic materials research problems, and to be a satisfactory approximation to that of the fusion process. The technology of high-intensity linear accelerators can readily be applied to provide the deuteron beam for the neutron source. Earlier applications included the Los Alamos Meson Physics Facility and the Fusion Materials Irradiation Test facility prototype. The key features of today's advanced accelerator technology are presented to illustrate the present state-of-the-art in terms of improved understanding of basic physical principles and engineering technique, and to show how these advances can be applied to present demands in a timely manner. These features include how to produce an intense beam current with the high quality required to minimize beam losses along the accelerator and transport system that could cause maintenance difficulties, by controlling the beam emittance through proper choice of the operating frequency, balancing of the forces acting on the beam, and realization in practical hardware. A most interesting aspect for materials researchers is the increased flexibility and opportunities for experimental configurations that a modern accelerator-based source could add to the set of available tools. 8 refs., 5 figs

  15. Chlorine detection in fly ash concrete using a portable neutron generator.

    Science.gov (United States)

    Naqvi, A A; Kalakada, Zameer; Al-Matouq, Faris A; Maslehuddin, M; Al-Amoudi, O S B

    2012-08-01

    The chlorine concentration in chloride-contaminated FA cement concrete specimens was measured using a portable neutron generator based prompt gamma-ray neutron activation (PGNAA) setup with the neutron generator and the gamma-ray detector placed side-by-side on one side of the concrete sample. The minimum detectable concentration of chlorine in FA cement concrete measured in the present study was comparable with previous results for larger accelerator based PGNAA setup. It shows the successful application of a portable neutron generator in concrete corrosion studies. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. 25th anniversary for Linac-2

    CERN Multimedia

    2003-01-01

    On Friday, 3 October 2003, the Linac team celebrated a quarter century of successful operation of one of its linear accelerators: Linac-2, the proton workhorse of the CERN accelerator complex. Linac-2, CERN's linear proton accelerator, has now been running for 25 years - ample reason for a small celebration. About 30 members of the original team (10 of the initially more than 50 are still working at CERN), and other CERN personnel met on 3 October 2003. Linac-2 is the first link in the accelerator chain Linac-2 - PS Booster - PS - SPS and eventually LHC. Beams from Linac-2 are used after further acceleration in the CERN complex for SPS fixed target physics; for antiproton production for the Antiproton Decelerator (AD); for test beams in the East Experimental Hall and in the PS; for nuclear physics at ISOLDE; for LHC test beams and in the past for both ISR physics and Antiproton production (AA/AC) and test beams in LEAR. Linac-2 was built to obtain higher intensities and better stability than with ...

  17. Calculation of neutron interior source distribution within subcritical fission-chain reacting systems for a prescribed power density generation

    International Nuclear Information System (INIS)

    Moraes, Leonardo R.C.; Alves Filho, Hermes; Barros, Ricardo C.

    2017-01-01

    Accelerator Driven Systems (ADS) are sub-critical systems stabilized by stationary external sources of neutrons. A system is subcritical when the removal by absorption and leakage exceeds the production by fission and tends to shut down. On the other hand, any subcritical system can be stabilized by including time-independent external sources of neutrons. The goal of this work is to determine the intensity of uniform and isotropic sources of neutrons that must be added inside all fuel regions of a subcritical system so that it becomes stabilized, generating a prescribed distribution of electric power. A computer program has been developed in Java language to estimate the intensity of stationary sources of neutrons that must be included in the fuel regions to drive the subcritical system with a fixed power distribution prescribed by the user. The mathematical model used to achieve this goal was the energy multigroup, slab-geometry neutron transport equation in the discrete ordinates (S N ) formulation and the response matrix method was applied to solve the forward and the adjoint S N problems. Numerical results are given to verify the present. (author)

  18. Calculation of neutron interior source distribution within subcritical fission-chain reacting systems for a prescribed power density generation

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, Leonardo R.C.; Alves Filho, Hermes; Barros, Ricardo C., E-mail: lrcmoraes@iprj.uerj.br, E-mail: halves@iprj.uerj.br, E-mail: ricardob@iprj.uerj.br [Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Programa de Pós-Graduação em Modelagem Computacional

    2017-07-01

    Accelerator Driven Systems (ADS) are sub-critical systems stabilized by stationary external sources of neutrons. A system is subcritical when the removal by absorption and leakage exceeds the production by fission and tends to shut down. On the other hand, any subcritical system can be stabilized by including time-independent external sources of neutrons. The goal of this work is to determine the intensity of uniform and isotropic sources of neutrons that must be added inside all fuel regions of a subcritical system so that it becomes stabilized, generating a prescribed distribution of electric power. A computer program has been developed in Java language to estimate the intensity of stationary sources of neutrons that must be included in the fuel regions to drive the subcritical system with a fixed power distribution prescribed by the user. The mathematical model used to achieve this goal was the energy multigroup, slab-geometry neutron transport equation in the discrete ordinates (S{sub N}) formulation and the response matrix method was applied to solve the forward and the adjoint S{sub N} problems. Numerical results are given to verify the present. (author)

  19. A neutron monitor for D-T neutron generator in the PGNAA-based online measurement system

    Science.gov (United States)

    Shan, Qing; Shengnan, Chu; Yongsheng, Ling; Pingkun, Cai; Wenbao, Jia

    2017-06-01

    A new type of neutron detector, which consists of polyethylene, an EJ200 plastic scintillator and fused silica, was proposed and optimized by the GEANT4 Monte Carlo simulation toolkit in our previous studies. The calculation method was also described for calculating the neutron flux in the preset condition. This paper reports the manufacturing of the prototype detector. Experiments are conducted to validate the feasibility of this detector. A D-T neutron generator and a 60Co gamma-ray source are used in the experiments. The designed detector and a He-3 proportional counter are simultaneously used to monitor the yield of the D-T neutron generator. A more universal calculation method is developed to enable the application of this detector to common conditions. The experimental results show that the performance of the designed detector is comparable to that of the He-3 proportional counter. The relative deviations between their normalized counts are less than 5%.

  20. Multifunctional pulse generator for high-intensity focused ultrasound system

    Science.gov (United States)

    Tamano, Satoshi; Yoshizawa, Shin; Umemura, Shin-Ichiro

    2017-07-01

    High-intensity focused ultrasound (HIFU) can achieve high spatial resolution for the treatment of diseases. A major technical challenge in implementing a HIFU therapeutic system is to generate high-voltage high-current signals for effectively exciting a multichannel HIFU transducer at high efficiencies. In this paper, we present the development of a multifunctional multichannel generator/driver. The generator can produce a long burst as well as an extremely high-voltage short pulse of pseudosinusoidal waves (trigger HIFU) and second-harmonic superimposed waves for HIFU transmission. The transmission timing, waveform, and frequency can be controlled using a field-programmable gate array (FPGA) via a universal serial bus (USB) microcontroller. The hardware is implemented in a compact printed circuit board. The test results of trigger HIFU reveal that the power consumption and the temperature rise of metal-oxide semiconductor field-effect transistors were reduced by 19.9% and 38.2 °C, respectively, from the previous design. The highly flexible performance of the novel generator/driver is demonstrated in the generation of second-harmonic superimposed waves, which is useful for cavitation-enhanced HIFU treatment, although the previous design exhibited difficulty in generating it.

  1. First demonstration of laser engagement of 1-Hz-injected flying pellets and neutron generation

    Science.gov (United States)

    Komeda, Osamu; Nishimura, Yasuhiko; Mori, Yoshitaka; Hanayama, Ryohei; Ishii, Katsuhiro; Nakayama, Suisei; Kitagawa, Yoneyoshi; Sekine, Takashi; Sato, Nakahiro; Kurita, Takashi; Kawashima, Toshiyuki; Kan, Hirofumi; Nakamura, Naoki; Kondo, Takuya; Fujine, Manabu; Azuma, Hirozumi; Motohiro, Tomoyoshi; Hioki, Tatsumi; Kakeno, Mitsutaka; Sunahara, Atsushi; Sentoku, Yasuhiko; Miura, Eisuke

    2013-01-01

    Pellet injection and repetitive laser illumination are key technologies for realizing inertial fusion energy. Numerous studies have been conducted on target suppliers, injectors, and tracking systems for flying pellet engagement. Here we for the first time demonstrate the pellet injection, counter laser beams' engagement and neutron generation. Deuterated polystyrene (CD) bead pellets, after free-falling for a distance of 18 cm at 1 Hz, are successfully engaged by two counter laser beams from a diode-pumped, ultra-intense laser HAMA. The laser energy, pulse duration, wavelength, and the intensity are 0.63 J per beam, 104 fs, and 811 nm, 4.7 × 1018 W/cm2, respectively. The irradiated pellets produce D(d,n)3He-reacted neutrons with a maximum yield of 9.5 × 104/4π sr/shot. Moreover, the laser is found out to bore a straight channel with 10 μm-diameter through the 1-mm-diameter beads. The results indicate potentially useful technologies and findings for the next step in realizing inertial fusion energy. PMID:24008696

  2. Survey of neutron spectra generated by the fission of heavy nuclei induced by fast neutrons

    International Nuclear Information System (INIS)

    Lovchikova, G.N.; Trufanov, A.M.

    1997-01-01

    A review of neutron fission spectra measurements is presented. This review and the results of this analysis was performed with the participation of the authors. It is shown that there is a need for additional measurements of the energy and angular distributions of secondary neutrons in order to improve the understanding of the neutron emission mechanism in fission. (author). 21 refs, 6 figs

  3. Next generation neutron scattering at Neutron Science Center project in JAERI

    International Nuclear Information System (INIS)

    Yamada, Yasusada; Watanabe, Noboru; Niimura, Nobuo; Morii, Yukio; Katano, Susumu; Aizawa, Kazuya; Suzuki, Jun-ichi; Koizumi, Satoshi; Osakabe, Toyotaka.

    1997-01-01

    Japan Atomic Energy Research Institute (JAERI) has promoted neutron scattering researches by means of research reactors in Tokai Research Establishment, and proposes 'Neutron Science Research Center' to develop the future prospect of the Tokai Research Establishment. The scientific fields which will be expected to progress by the neutron scattering experiments carried out at the proposed facility in the Center are surveyed. (author)

  4. Results and plans on the development of a pulsed neutron generator

    International Nuclear Information System (INIS)

    Sztaricskai, T.; Vasvary, L.; Petoe, G.

    1976-01-01

    Using the vacuum system of an old van de Graaff machine a new pulsed neutron generator has been developed. The block diagram, the scheme of generators arrangement and the electrode system of the ion bunching parts are shown

  5. Feasibility study on medical isotope production using a compact neutron generator.

    Science.gov (United States)

    Leung, Ka-Ngo; Leung, James K; Melville, Graeme

    2018-07-01

    Compact neutron generators can provide high flux of neutrons with energies ranging from thermal (0.025 eV) to 14 MeV. Recent measurements demonstrated high neutron yields from the D- 7 Li fusion reaction at an interaction energy of 500 keV. Using the D- 7 Li reaction and applying new advancements in high flux neutron generator technology along with the commercial availability of high voltage DC power supplies enables the production of useful quantities of radioisotopes for medical applications. Using the known neutron reaction cross-sections, it has been estimated that hundreds-to-thousands MBq (or tens-to-hundreds mCi) of 99 Mo, 225 Ac, 64 Cu and 67 Cu can be obtained from a compact high flux neutron generator. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Campbelling-type theory of fission chamber signals generated by neutron chains in a multiplying medium

    International Nuclear Information System (INIS)

    Pál, L.; Pázsit, I.

    2015-01-01

    The signals of fission chambers are usually evaluated with the help of the co-called Campbelling techniques. These are based on the Campbell theorem, which states that if the primary incoming events, generating the detector pulses, are independent, then relationships exist between the moments of various orders of the signal in the current mode. This gives the possibility to determine the mean value of the intensity of the detection events, which is proportional to the static flux, from the higher moments of the detector current, which has certain advantages. However, the main application area of fission chambers is measurements in power reactors where, as is well known, the individual detection events are not independent, due to the branching character of the neutron chains (neutron multiplication). Therefore it is of interest to extend the Campbelling-type theory for the case of correlated neutron events. Such a theory could address two questions: partly, to investigate the bias when the traditional Campbell techniques are used for correlated incoming events; and partly, to see whether the correlation properties of the detection events, which carry information on the multiplying medium, could be extracted from the measurements. This paper is devoted to the investigation of these questions. The results show that there is a potential possibility to extract the same information from fission chamber signals in the current mode as with the Rossi- or Feynman-alpha methods, or from coincidence and multiplicity measurements, which so far have required detectors working in the pulse mode. It is also shown that application of the standard Campbelling techniques to neutron detection in multiplying systems does not lead to an error for estimating the stationary flux as long as the detector is calibrated in in situ measurements

  7. Use of a high repetition rate neutron generator for in vivo body composition measurements via neutron inelastic scattering

    International Nuclear Information System (INIS)

    Kehayias, J.J.; Ellis, K.J.; Cohn, S.H.; Weinlein, J.H.

    1986-01-01

    A small D-T neutron generator with a high pulse rate is used for the in vivo measurement of body carbon, oxygen and hydrogen. The core of the neutron generator is a 13 cm-long Zetatron tube pulsed at a rate of 10 kHz delivering 10 3 to 10 4 neutrons per pulse. A target-current feedback system regulates the source of the accelerator to assure constant neutron output. Carbon is measured by detecting the 4.44 MeV γ-rays from inelastic scattering. The short half-life of the 4.44 MeV state of carbon requires detection of the γ-rays during the 10 μs neutron pulse. Generators with low pulsing rate were found inappropriate for carbon measurements because of their low duty-cycle (high neutron output during the pulse). In vivo measurements were performed with normal volunteers using a scanning bed facility for a dose less than 25 mrem. This technique offers medical as well as general bulk analysis applications. 8 refs., 5 figs

  8. A SUPER-CONDUCTING LINAC DRIVER FOR THE HFBR.

    Energy Technology Data Exchange (ETDEWEB)

    Alessi, J.; Raparia, D.; Ruggiero, A.G.

    2000-08-21

    This paper reports on the feasibility study of a proton Super-Conducting Linac (SCL) as a driver for the High-Flux Breeder Reactor (HFBR) at Brookhaven National Laboratory (BNL). The Linac operates in Continuous Wave (CW) mode to produce an average 10 MW of beam power. The Linac beam energy is 1.0 GeV. The average proton beam intensity in exit is 10 mA.

  9. Prompt-gamma neutron activation analysis system design: Effects of D-T versus D-D neutron generator source selection

    Science.gov (United States)

    Prompt-gamma neutron activation (PGNA) analysis is used for the non-invasive measurement of human body composition. Advancements in portable, compact neutron generator design have made those devices attractive as neutron sources. Two distinct generators are available: D-D with 2.5 MeV and D-T with...

  10. The potential of detecting intermediate-scale biomass and canopy interception in a coniferous forest using cosmic-ray neutron intensity measurements and neutron transport modeling

    Science.gov (United States)

    Andreasen, M.; Looms, M. C.; Bogena, H. R.; Desilets, D.; Zreda, M. G.; Sonnenborg, T. O.; Jensen, K. H.

    2014-12-01

    The water stored in the various compartments of the terrestrial ecosystem (in snow, canopy interception, soil and litter) controls the exchange of the water and energy between the land surface and the atmosphere. Therefore, measurements of the water stored within these pools are critical for the prediction of e.g. evapotranspiration and groundwater recharge. The detection of cosmic-ray neutron intensity is a novel non-invasive method for the quantification of continuous intermediate-scale soil moisture. The footprint of the cosmic-ray neutron probe is a hemisphere of a few hectometers and subsurface depths of 10-70 cm depending on wetness. The cosmic-ray neutron method offers measurements at a scale between the point-scale measurements and large-scale satellite retrievals. The cosmic-ray neutron intensity is inversely correlated to the hydrogen stored within the footprint. Overall soil moisture represents the largest pool of hydrogen and changes in the soil moisture clearly affect the cosmic-ray neutron signal. However, the neutron intensity is also sensitive to variations of hydrogen in snow, canopy interception and biomass offering the potential to determine water content in such pools from the signal. In this study we tested the potential of determining canopy interception and biomass using cosmic-ray neutron intensity measurements within the framework of the Danish Hydrologic Observatory (HOBE) and the Terrestrial Environmental Observatories (TERENO). Continuous measurements at the ground and the canopy level, along with profile measurements were conducted at towers at forest field sites. Field experiments, including shielding the cosmic-ray neutron probes with cadmium foil (to remove lower-energy neutrons) and measuring reference intensity rates at complete water saturated conditions (on the sea close to the HOBE site), were further conducted to obtain an increased understanding of the physics controlling the cosmic-ray neutron transport and the equipment used

  11. Beam Dynamics Studies and the Design, Fabrication and Testing of Superconducting Radiofrequency Cavity for High Intensity Proton Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Saini, Arun [Univ. of Delhi, New Delhi (India)

    2012-03-01

    The application horizon of particle accelerators has been widening significantly in recent decades. Where large accelerators have traditionally been the tools of the trade for high-energy nuclear and particle physics, applications in the last decade have grown to include large-scale accelerators like synchrotron light sources and spallation neutron sources. Applications like generation of rare isotopes, transmutation of nuclear reactor waste, sub-critical nuclear power, generation of neutrino beams etc. are next area of investigation for accelerator scientific community all over the world. Such applications require high beam power in the range of few mega-watts (MW). One such high intensity proton beam facility is proposed at Fermilab, Batavia, US, named as Project-X. Project-X facility is based on H- linear accelerator (linac), which will operate in continuous wave (CW) mode and accelerate H- ion beam with average current of 1 mA from kinetic energy of 2.5 MeV to 3 GeV to deliver 3MW beam power. One of the most challenging tasks of the Project-X facility is to have a robust design of the CW linac which can provide high quality beam to several experiments simultaneously. Hence a careful design of linac is important to achieve this objective.

  12. A D-D/D-T fusion reaction based neutron generator system for liver tumor BNCT

    International Nuclear Information System (INIS)

    Koivunoro, H.; Lou, T.P.; Leung, K. N.; Reijonen, J.

    2003-01-01

    Boron-neutron capture therapy (BNCT) is an experimental radiation treatment modality used for highly malignant tumor treatments. Prior to irradiation with low energetic neutrons, a 10B compound is located selectively in the tumor cells. The effect of the treatment is based on the high LET radiation released in the 10 B(n,α) 7 Li reaction with thermal neutrons. BNCT has been used experimentally for brain tumor and melanoma treatments. Lately applications of other severe tumor type treatments have been introduced. Results have shown that liver tumors can also be treated by BNCT. At Lawrence Berkeley National Laboratory, various compact neutron generators based on D-D or D-T fusion reactions are being developed. The earlier theoretical studies of the D-D or D-T fusion reaction based neutron generators have shown that the optimal moderator and reflector configuration for brain tumor BNCT can be created. In this work, the applicability of 2.5 MeV neutrons for liver tumor BNCT application was studied. The optimal neutron energy for external liver treatments is not known. Neutron beams of different energies (1eV < E < 100 keV) were simulated and the dose distribution in the liver was calculated with the MCNP simulation code. In order to obtain the optimal neutron energy spectrum with the D-D neutrons, various moderator designs were performed using MCNP simulations. In this article the neutron spectrum and the optimized beam shaping assembly for liver tumor treatments is presented

  13. IEC-based neutron generator for security inspection system

    International Nuclear Information System (INIS)

    Miley, G.H.; Wu, L.; Kim, H.J.

    2005-01-01

    Use of a combined X-ray and neutron source for security inspections based on Inertial Electrostatic Confinement (IEC) fusion is discussed. Current inspection systems typically use X-ray techniques, but thermal neutron analysis (TNA) and fast neutron analysis (FNA), allow expanded detection of certain types of explosives. The integrated unit proposed here uses three separate IEC sources producing 14 and 2.45 MeV neutrons plus soft X-rays. This combination allows multiple detection methods with the composite signal analysis being done by a fuzzy logic system, significantly reducing false signals. (author)

  14. Thermionic RF Gun and Linac Pre-Injector for SPEAR3

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.

    2003-08-11

    Preparations are underway to upgrade the Spear2 to the third generation light source. Installation of all the subsystems will start in April 2003. Although the Spear3 RF system is entirely different from the present form, the pre-injector gun/linac and booster synchrotron will remain the same even after the upgrade. The thermionic rf gun reliability and stability are to be improved to inject 500 mA of stored current in shortest possible time. When a top-up mode is enforced, where the stored beam decay is replenished to maintain the constant current and thus constant light intensity, the Spear3 will take injection every few minutes. In that case the gun, linac, and booster must stay on at all times. In this report we will describe some improvements made on the gun and linac in the recent past, as well as their present performance and future upgrade to be made.

  15. NEUTRON GENERATOR FACILITY AT SFU: GEANT4 DOSE RATE PREDICTION AND VERIFICATION.

    Science.gov (United States)

    Williams, J; Chester, A; Domingo, T; Rizwan, U; Starosta, K; Voss, P

    2016-11-01

    Detailed dose rate maps for a neutron generator facility at Simon Fraser University were produced via the GEANT4 Monte Carlo framework. Predicted neutron dose rates throughout the facility were compared with radiation survey measurements made during the facility commissioning process. When accounting for thermal neutrons, the prediction and measurement agree within a factor of 2 or better in most survey locations, and within 10 % inside the vault housing the neutron generator. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Generation of radiation by intense plasma and electromagnetic undulators

    International Nuclear Information System (INIS)

    Joshi, C.

    1989-01-01

    This is a second year progress report which details the work on the generation of radiation by intense plasma and electromagnetic undulators being carried out at UCLA. The status of the experimental work is described and the future directions are outlined. We have completed the first phase of experiments on the plasma wiggler generation and characterization. Suitability of a null-pinch as a plasma source was investigated in great detail. It is found that a w of a few percent can be excited but there are trapped magnetic fields within null-pinch plasma which hinder the injection of the electrons. A new more uniform and field-free plasma source is now being characterized

  17. Generation of radiation by intense plasma and electromagnetic undulators

    International Nuclear Information System (INIS)

    Joshi, C.

    1989-01-01

    This is a second year progress report which details the work on the generation of radiation by intense plasma and electromagnetic undulators being carried out at UCLA. The status of the experimental work is described and the future directions are outlined. We have completed the first phase of experiments on the plasma wiggler generation and characterization. Suitability of a θ-pinch as a plasma source was investigated in great detail. It is found that a w of a few percent can be excited but there are trapped magnetic fields within θ-pinch plasma which hinder the injection of the electrons. A few more uniform and field-free plasma source is now being characterized. 8 refs., 5 figs

  18. Intense relativistic electron beam generation from KALI-5000 pulse accelerator

    International Nuclear Information System (INIS)

    Roy, A.; Mondal, J.; Mitra, S.; Durga Praveen Kumar, D.; Sharma, Archana; Nagesh, K.V.; Chakravarthy, D.P.

    2006-01-01

    Intense Relativistic Electron Beam (IREB) with parameters 420 keV, 22 kA, 100 ns has been generated from indigenously developed pulse power system KALI- 5000. High current electron beam is generated from explosive field emission graphite cathodes. Studies have been conducted by changing the diameter of graphite cathode and also the anode cathode gap. In order to avoid prepulse effect it was concluded that anode cathode (AK) gap should be kept larger than estimated by the Child Langmuir relation. Beam voltage has been measured by a copper sulphate voltage divider, beam current by a self integrating Rogowski coil and B-dot probe. Electron beam diode Impedance and Perveance were obtained from the experimentally measured beam voltage and current. (author)

  19. SNS superconducting linac

    International Nuclear Information System (INIS)

    Sundelin, Ronald M.

    2001-01-01

    The Spallation Neutron Source (SNS) decided in early 2000 to use superconducting RF (SRF) in the linac at energies above 185 MeV. Since the SNS duty cycle is 6%, the SRF and normal conducting approaches have capital costs which are about the same, but operating costs and future upgradability are improved by using SRF. The current status of cavity and cryomodule development and procurement, including the basis for decisions made, is discussed. The current plan includes use of 805 MHz, 6-cell cavities with geometrical betas of 0.61 and 0.81. There are 33 medium beta and 60 high beta cavities in 11 and 15 cryomodules, respectively. Each cavity (except the 93rd) is powered by a 550 kW pulsed klystron. Issues addressed include choice of peak surface gradient, optimization of cavity shape, selection of a scaled KEK input power coupler, selection of scaled TESLA higher mode couplers, and control of the effects of higher order modes on the beam. (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