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Sample records for accelerator driven neutron

  1. Accelerator-driven neutron source for cargo screening

    NASA Astrophysics Data System (ADS)

    Ludewigt, B. A.; Bleuel, D. L.; Hoff, M. D.; Kwan, J. W.; Li, D.; Ratti, A.; Staples, J. W.; Virostek, S. P.; Wells, R. P.

    2007-08-01

    Advanced neutron interrogation systems for screening sea-land cargo containers for shielded special nuclear materials (SNM) require a high-yield neutron source to achieve the desired detection probability, false alarm rate, and throughput. The design of an accelerator-driven neutron source is described that utilizes the D(d,n)3He reaction to produce a forward directed beam of up to 8.5 MeV neutrons. The key components of the neutron source are a high-current radio frequency quadrupole (RFQ) accelerator and a neutron production gas target. The 5.1 m long, 200 MHz RFQ accelerates a 40 mA deuteron beam from a microwave-driven ion source coupled to an electrostatic low energy beam transport (LEBT) system to 6 MeV. At a 5% duty factor, the time-average D+ beam current on target is 1.5 mA. A thin entrance window has been designed for the deuterium gas target that can withstand the high beam power and the gas pressure. The source will be capable of delivering a flux >1 × 107 n/(cm2 s) at a distance of 2.5 m from the target and will allow full testing and demonstration of a cargo screening system based on neutron stimulated SNM signatures.

  2. Accelerator-driven boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Edgecock, Rob

    2014-05-01

    Boron Neutron Capture Therapy is a binary treatment for certain types of cancer. It works by loading the cancerous cells with a boron-10 carrying compound. This isotope has a large cross-section for thermal neutrons, the reaction producing a lithium nucleus and alpha particle that kill the cell in which they are produced. Recent studies of the boron carrier compound indicate that the uptake process works best in particularly aggressive cancers. Most studied is glioblastoma multiforme and a trial using a combination of BNCT and X-ray radiotherapy has shown an increase of nearly a factor of two in mean survival over the state of the art. However, the main technical problem with BNCT remains producing a sufficient flux of neutrons for a reasonable treatment duration in a hospital environment. This paper discusses this issue.

  3. Intense Pulsed Neutron Emission from a Compact Pyroelectric Driven Accelerator

    SciTech Connect

    Tang, V; Meyer, G; Falabella, S; Guethlein, G; Sampayan, S; Kerr, P; Rusnak, B; Morse, J

    2008-10-08

    Intense pulsed D-D neutron emission with rates >10{sup 10} n/s during the pulse, pulse widths of {approx}100's ns, and neutron yields >10 k per pulse are demonstrated in a compact pyroelectric accelerator. The accelerator consists of a small pyroelectric LiTaO{sub 3} crystal which provides the accelerating voltage and an independent compact spark plasma ion source. The crystal voltage versus temperature is characterized and compare well with theory. Results show neutron output per pulse that scales with voltage as V{approx}1.7. These neutron yields match a simple model of the system at low voltages but are lower than predicted at higher voltages due to charge losses not accounted for in the model. Interpretation of the data against modeling provides understanding of the accelerator and in general pyroelectric LiTaO{sub 3} crystals operated as charge limited negative high voltage targets. The findings overall serve as the proof-of-principle and basis for pyroelectric neutron generators that can be pulsed, giving peak neutron rates orders of magnitude greater than previous work, and notably increase the potential applications of pyroelectric based neutron generators.

  4. ITEP subcritical neutron generator driven by charged particle accelerator

    SciTech Connect

    Shvedov, Oleg V.; Chuvilo, Ivan V.; Kulikov, Evgeny V.; Vasiliev, Valery V.; Igumnov, Mikhail M.; Kozodaev, Alexander M.; Volkov, Evgeny B.; Lopatkin, Alexander V.

    1995-09-15

    A research facility prototype including a combination of a linear accelerator, a neutron generating target, a subcritical multiplying system is discussed. Principles of the 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.

  5. Beamed neutron emission driven by laser accelerated light ions

    NASA Astrophysics Data System (ADS)

    Kar, S.; Green, A.; Ahmed, H.; Alejo, A.; Robinson, A. P. L.; Cerchez, M.; Clarke, R.; Doria, D.; Dorkings, S.; Fernandez, J.; Mirfayzi, S. R.; McKenna, P.; Naughton, K.; Neely, D.; Norreys, P.; Peth, C.; Powell, H.; Ruiz, J. A.; Swain, J.; Willi, O.; Borghesi, M.

    2016-05-01

    Highly anisotropic, beam-like neutron emission with peak flux of the order of 109 n/sr was obtained from light nuclei reactions in a pitcher–catcher scenario, by employing MeV ions driven by a sub-petawatt laser. The spatial profile of the neutron beam, fully captured for the first time by employing a CR39 nuclear track detector, shows a FWHM divergence angle of ∼ 70^\\circ , with a peak flux nearly an order of magnitude higher than the isotropic component elsewhere. The observed beamed flux of neutrons is highly favourable for a wide range of applications, and indeed for further transport and moderation to thermal energies. A systematic study employing various combinations of pitcher–catcher materials indicates the dominant reactions being d(p, n+p)1H and d(d,n)3He. Albeit insufficient cross-section data are available for modelling, the observed anisotropy in the neutrons’ spatial and spectral profiles is most likely related to the directionality and high energy of the projectile ions.

  6. Neutron source in the MCNPX shielding calculating for electron accelerator driven facility

    SciTech Connect

    Zhong, Z.; Gohar, Y.

    2012-07-01

    Argonne National Laboratory (ANL) of USA and Kharkov Inst. of Physics and Technology (KIPT) of Ukraine have been collaborating on the design development of an experimental neutron source facility. It is an accelerator driven system (ADS) utilizing a subcritical assembly driven by electron accelerator. The facility will be utilized for performing basic and applied nuclear researches, producing medical isotopes, and training young nuclear specialists. Monte Carlo code MCNPX has been utilized as a design tool due to its capability to transport electrons, photons, and neutrons at high energies. However the facility shielding calculations with MCNPX need enormous computational resources and the small neutron yield per electron makes sampling difficulty for the Monte Carlo calculations. A method, based on generating and utilizing neutron source file, was proposed and tested. This method reduces significantly the required computer resources and improves the statistics of the calculated neutron dose outside the shield boundary. However the statistical errors introduced by generating the neutron source were not directly represented in the results, questioning the validity of this methodology, because an insufficiently sampled neutron source can cause error on the calculated neutron dose. This paper presents a procedure for the validation of the generated neutron source file. The impact of neutron source statistic on the neutron dose is examined by calculating the neutron dose as a function of the number of electron particles used for generating the neutron source files. When the value of the calculated neutron dose converges, it means the neutron source has scored sufficient records and statistic does not have apparent impact on the calculated neutron dose. In this way, the validity of neutron source and the shield analyses could be verified. (authors)

  7. Study of an External Neutron Source for an Accelerator-Driven System using the PHITS Code

    SciTech Connect

    Sugawara, Takanori; Iwasaki, Tomohiko; Chiba, Takashi

    2005-05-24

    A code system for the Accelerator Driven System (ADS) has been under development for analyzing dynamic behaviors of a subcritical core coupled with an accelerator. This code system named DSE (Dynamics calculation code system for a Subcritical system with an External neutron source) consists of an accelerator part and a reactor part. The accelerator part employs a database, which is calculated by using PHITS, for investigating the effect related to the accelerator such as the changes of beam energy, beam diameter, void generation, and target level. This analysis method using the database may introduce some errors into dynamics calculations since the neutron source data derived from the database has some errors in fitting or interpolating procedures. In this study, the effects of various events are investigated to confirm that the method based on the database is appropriate.

  8. Radiation effects in materials for accelerator-driven neutron technologies

    SciTech Connect

    Wechsler, M.S.; Lin, C.; Sommer, W.F.; Daemen, L.L.; Ferguson, P.D.

    1997-03-01

    The materials exposed to the most damaging radiation environments in an SNS (spallation neutron source) are those in the path of the incident proton beam. This includes target and window materials. These materials will experience damage from the incident protons and the spallation neutrons. The major solid targets in operating SNS`s and under consideration for the 1--5 MW SNS`s are W, U, and Pb. Tungsten is the target material at LANSCE, and is the project target material for an upgraded LANSCE target that is presently being designed. It is also the projected target material for the tritium producing SNS under design at LANL. In this paper, the authors present the results of spallation radiation damage calculations (displacement and He production) for tungsten.

  9. Applications of compact accelerator-driven neutron sources: An updated assessment from the perspective of materials research in Italy

    SciTech Connect

    Andreani, C.; Anderson, I. S.; Carpenter, J. M.; Festa, G.; Gorini, G.; Loong, C. -K.; Senesi, R.

    2014-12-24

    In 2005 the International Atomic Energy Agency (IAEA) in Vienna published a report [1] on ‘Development Opportunities of Small and Medium Scale Accelerator Driven Neutron Sources’ which summarized the prospect of smaller sources in supporting the large spallation neutron sources for materials characterization and instrumentation, a theme advocated by Bauer, Clausen, Mank, and Mulhauser in previous publications [2-4]. In 2010 the Union for Compact Accelerator-driven Neutron Sources (UCANS) was established [5], galvanizing cross-disciplinary collaborations on new source and neutronics development and expanded applications based on both slow-neutron scattering and other neutron-matter interactions of neutron energies ranging from 10⁻⁶ to 10² MeV [6]. Here, we first cover the recent development of ongoing and prospective projects of compact accelerator-driven neutron sources (CANS) but concentrate on prospective accelerators currently proposed in Italy. Two active R&D topics, irradiation effects on electronics and cultural heritage studies, are chosen to illustrate the impact of state-of-the-art CANS on these programs with respect to the characteristics and complementarity of the accelerator and neutronics systems as well as instrumentation development.

  10. Applications of compact accelerator-driven neutron sources: An updated assessment from the perspective of materials research in Italy

    DOE PAGESBeta

    Andreani, C.; Anderson, I. S.; Carpenter, J. M.; Festa, G.; Gorini, G.; Loong, C. -K.; Senesi, R.

    2014-12-24

    In 2005 the International Atomic Energy Agency (IAEA) in Vienna published a report [1] on ‘Development Opportunities of Small and Medium Scale Accelerator Driven Neutron Sources’ which summarized the prospect of smaller sources in supporting the large spallation neutron sources for materials characterization and instrumentation, a theme advocated by Bauer, Clausen, Mank, and Mulhauser in previous publications [2-4]. In 2010 the Union for Compact Accelerator-driven Neutron Sources (UCANS) was established [5], galvanizing cross-disciplinary collaborations on new source and neutronics development and expanded applications based on both slow-neutron scattering and other neutron-matter interactions of neutron energies ranging from 10⁻⁶ to 10²more » MeV [6]. Here, we first cover the recent development of ongoing and prospective projects of compact accelerator-driven neutron sources (CANS) but concentrate on prospective accelerators currently proposed in Italy. Two active R&D topics, irradiation effects on electronics and cultural heritage studies, are chosen to illustrate the impact of state-of-the-art CANS on these programs with respect to the characteristics and complementarity of the accelerator and neutronics systems as well as instrumentation development.« less

  11. Radiation effects in materials for accelerator-driven neutron technologies. Revision

    SciTech Connect

    Wechsler, M.S.; Lin, C.; Sommer, W.F.

    1997-04-01

    Accelerator-driven neutron technologies use spallation neutron sources (SNS`s) in which high-energy protons bombard a heavy-element target and spallation neutrons are produced. The materials exposed to the most damaging radiation environments in an SNS are those in the path of the incident proton beam. This includes target and window materials. These materials will experience damage from the incident protons and the spallation neutrons. In addition, some materials will be damaged by the spallation neutrons alone. The principal materials of interest for SNS`s are discussed elsewhere. The target should consist of one or more heavy elements, so as to increase the number of neutrons produced per incident proton. A liquid metal target (e.g., Pb, Bi, Pb-Bi, Pb-Mg, and Hg) has the advantage of eliminating the effects of radiation damage on the target material itself, but concerns over corrosion problems and the influence of transmutants remain. The major solid targets in operating SNS`s and under consideration for the 1-5 MW SNS`s are W, U, and Pb. Tungsten is the target material at LANSCE, and is the projected target material for an upgraded LANSCE target that is presently being designed. It is also the projected target material for the tritium producing SNS under design at LANL. In this paper, the authors present the results of spallation radiation damage calculations (displacement and He production) for tungsten.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  13. Benchmarking shielding simulations for an accelerator-driven spallation neutron source

    NASA Astrophysics Data System (ADS)

    Cherkashyna, Nataliia; DiJulio, Douglas D.; Panzner, Tobias; Rantsiou, Emmanouela; Filges, Uwe; Ehlers, Georg; Bentley, Phillip M.

    2015-08-01

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

  14. Burn-up and neutron economy of accelerator-driven reactor

    SciTech Connect

    Takahashi, H.; Yang, W.; An, Y.; Yamazaki, Y.

    1997-07-01

    It is desirable to have only a small reactivity change in the large burn-up of a solid fuel fast reactor, so that the number of replacements or shuffling of the fuel can be reduced, and plant factor accordingly increased. Also, this reduces the number of control rods needed for the change in burn-up reactivity. In subcritical operation, power controlled by beam power is suggested, but this practice is not as economical as the use of control rods and makes more careful operation of the accelerator is required due to changes in the wake field. In subcritical operation, even a slightly subcritical one, the safety problems associated with a hard neutron spectrum can be alleviated. Neutron leakage from a flattened core, which is needed for operation of the critical fast reactor can be lessen by using the non flat core which has good neutron economy. For generating nuclear energy, it is essential to have a high neutron economy, although breeding the fuel is not welcomed in the present political climate, as is needed for transmuting long lived fission products. In contrast to the breeder, the accelerator driven reactor can separate the energy production from fuel production and processing. Thus, it is suited for non-proliferation of nuclear material by prohibiting the processing and production of fuel in the unrestricted area so this can be only done in international controlled areas which are restricted and remote.

  15. Laser-driven x-ray and neutron source development for industrial applications of plasma accelerators

    NASA Astrophysics Data System (ADS)

    Brenner, C. M.; Mirfayzi, S. R.; Rusby, D. R.; Armstrong, C.; Alejo, A.; Wilson, L. A.; Clarke, R.; Ahmed, H.; Butler, N. M. H.; Haddock, D.; Higginson, A.; McClymont, A.; Murphy, C.; Notley, M.; Oliver, P.; Allott, R.; Hernandez-Gomez, C.; Kar, S.; McKenna, P.; Neely, D.

    2016-01-01

    Pulsed beams of energetic x-rays and neutrons from intense laser interactions with solid foils are promising for applications where bright, small emission area sources, capable of multi-modal delivery are ideal. Possible end users of laser-driven multi-modal sources are those requiring advanced non-destructive inspection techniques in industry sectors of high value commerce such as aerospace, nuclear and advanced manufacturing. We report on experimental work that demonstrates multi-modal operation of high power laser-solid interactions for neutron and x-ray beam generation. Measurements and Monte Carlo radiation transport simulations show that neutron yield is increased by a factor ~2 when a 1 mm copper foil is placed behind a 2 mm lithium foil, compared to using a 2 cm block of lithium only. We explore x-ray generation with a 10 picosecond drive pulse in order to tailor the spectral content for radiography with medium density alloy metals. The impact of using  >1 ps pulse duration on laser-accelerated electron beam generation and transport is discussed alongside the optimisation of subsequent bremsstrahlung emission in thin, high atomic number target foils. X-ray spectra are deconvolved from spectrometer measurements and simulation data generated using the GEANT4 Monte Carlo code. We also demonstrate the unique capability of laser-driven x-rays in being able to deliver single pulse high spatial resolution projection imaging of thick metallic objects. Active detector radiographic imaging of industrially relevant sample objects with a 10 ps drive pulse is presented for the first time, demonstrating that features of 200 μm size are resolved when projected at high magnification.

  16. On the Neutron Kinetics and Control of Accelerator-Driven Systems

    SciTech Connect

    Cacuci, D.G.

    2004-09-15

    This work addresses fundamental aspects of the time- and space-dependent behavior of an Accelerator-Driven Subcritical Core System (ADS) and presents a paradigm ADS neutron kinetics model that is solved exactly. Thus, this paradigm model can serve for benchmarking two- and/or three-dimensional computational tools. Furthermore, this work also proposes a global optimal control theory framework for the operation and control of an ADS. This framework encompasses conceptually the time- and space-dependent behavior of the ADS coupled neutron kinetics/thermal-hydraulic balance equations and aims at the optimal control of ADS operational objectives, which would include minimization of local flux disturbances, load and source following, etc. Importantly, this new conceptual framework makes no use of a 'fictitious ADS steady state' and yields the correct and complete (i.e., including sources) adjoint equations, without leaving any room for ambiguities. Thus, this new conceptual framework provides a natural basis for developing new computational methods and corresponding verification experiments specifically tailored for the control and operation of ADS.

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

    NASA Astrophysics Data System (ADS)

    Zendler, C.; Bentley, P. M.

    2016-08-01

    The European Spallation Source (ESS) is a long pulse spallation neutron source that is currently under construction in Lund, Sweden. A considerable fraction of the 22 planned instruments extend as far as 75-150 m from the source. In such long beam lines, misalignment between neutron guide segments can decrease the neutron transmission significantly. In addition to a random misalignment from installation tolerances, the ground on which ESS is built can be expected to sink with time, and thus shift the neutron guide segments further away from the ideal alignment axis in a systematic way. These systematic errors are correlated to the ground structure, position of buildings and shielding installation. Since the largest deformation is expected close to the target, even short instruments might be noticeably affected. In this study, the effect of this systematic misalignment on short and long ESS beam lines is analyzed, and a possible mitigation by overillumination of subsequent guide sections investigated.

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

    SciTech Connect

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

    2007-02-15

    An over-dense microwave driven ion source capable ofproducing deuterium (or hydrogen) beams at 100-200 mA/cm2 and with atomicfraction>90 percent was designed and tested with an electrostaticlow energy beam transport section (LEBT). This ion source wasincorporatedinto the design of an Accelerator Driven Neutron Source(ADNS). The other key components in the ADNS include a 6 MeV RFQaccelerator, a beam bending and scanning system, and a deuterium gastarget. In this design a 40 mA D+ beam is produced from a 6 mm diameteraperture using a 60 kV extraction voltage. The LEBT section consists of 5electrodes arranged to form 2 Einzel lenses that focus the beam into theRFQ entrance. To create the ECR condition, 2 induction coils are used tocreate ~; 875 Gauss on axis inside the source chamber. To prevent HVbreakdown in the LEBT a magnetic field clamp is necessary to minimize thefield in this region. Matching of the microwave power from the waveguideto the plasma is done by an autotuner. We observed significantimprovement of the beam quality after installing a boron nitride linerinside the ion source. The measured emittance data are compared withPBGUNS simulations.

  19. Conceptual design of thorium-fuelled Mitrailleuse accelerator-driven subcritical reactor using D-Be neutron source

    SciTech Connect

    Kokubo, Y.; Kamei, T.

    2012-07-01

    A distributed accelerator is a charged-particle accelerator that uses a new acceleration method based on repeated electrostatic acceleration. This method offers outstanding benefits not possible with the conventional radio-frequency acceleration method, including: (1) high acceleration efficiency, (2) large acceleration current, and (3) lower failure rate made possible by a fully solid-state acceleration field generation circuit. A 'Mitrailleuse Accelerator' is a product we have conceived to optimize this distributed accelerator technology for use with a high-strength neutron source. We have completed the conceptual design of a Mitrailleuse Accelerator and of a thorium-fuelled subcritical reactor driven by a Mitrailleuse Accelerator. This paper presents the conceptual design details and approach to implementing the subcritical reactor core. We will spend the next year or so on detailed design work, and then will start work on developing a prototype for demonstration. If there are no obstacles in setting up a development organization, we expect to finish verifying the prototype's performance by the third quarter of 2015. (authors)

  20. Optimum design and criticality safety of a beam-shaping assembly with an accelerator-driven subcritical neutron multiplier for boron neutron capture therapies.

    PubMed

    Hiraga, F

    2015-12-01

    The beam-shaping assembly for boron neutron capture therapies with a compact accelerator-driven subcritical neutron multiplier was designed so that an epithermal neutron flux of 1.9×10(9) cm(-2) s(-1) at the treatment position was generated by 5 MeV protons in a beam current of 2 mA. Changes in the atomic density of (135)Xe in the nuclear fuel due to the operation of the beam-shaping assembly were estimated. The criticality safety of the beam-shaping assembly in terms of Xe poisoning is discussed. PMID:26235186

  1. Monitoring method for neutron flux for a spallation target in an accelerator driven sub-critical system

    NASA Astrophysics Data System (ADS)

    Zhao, Qiang, He, Zhi-Yong; Yang, Lei; Zhang, Xue-Ying; Cui, Wen-Juan; Chen, Zhi-Qiang; Xu, Hu-Shan

    2016-07-01

    In this paper, we study a monitoring method for neutron flux for the spallation target used in an accelerator driven sub-critical (ADS) system, where a spallation target located vertically at the centre of a sub-critical core is bombarded vertically by high-energy protons from an accelerator. First, by considering the characteristics in the spatial variation of neutron flux from the spallation target, we propose a multi-point measurement technique, i.e. the spallation neutron flux should be measured at multiple vertical locations. To explain why the flux should be measured at multiple locations, we have studied neutron production from a tungsten target bombarded by a 250 MeV-proton beam with Geant4-based Monte Carlo simulations. The simulation results indicate that the neutron flux at the central location is up to three orders of magnitude higher than the flux at lower locations. Secondly, we have developed an effective technique in order to measure the spallation neutron flux with a fission chamber (FC), by establishing the relation between the fission rate measured by FC and the spallation neutron flux. Since this relation is linear for a FC, a constant calibration factor is used to derive the neutron flux from the measured fission rate. This calibration factor can be extracted from the energy spectra of spallation neutrons. Finally, we have evaluated the proposed calibration method for a FC in the environment of an ADS system. The results indicate that the proposed method functions very well. Supported by Strategic Priority Research Program of Chinese Academy of Sciences (XDA03010000 and XDA03030000) and the National Natural Science Foundation of China(91426301).

  2. Mechanical Design and Analysis of a 200 MHz, Bolt-together RFQ forthe Accelerator Driven Neutron Source

    SciTech Connect

    Virostek, Steve; Hoff, Matt; Li, Derun; Staples, John; Wells,Russell

    2007-06-20

    A high-yield neutron source to screen sea-land cargocontainers for shielded Special Nuclear Materials (SNM) has been designedat LBNL [1,2]. The Accelerator-Driven Neutron Source (ADNS) uses theD(d,n)3He reaction to create a forward directed neutron beam. Keycomponents are a high-current radio-frequency quadrupole (RFQ)accelerator and a high-power target capable of producing a neutron fluxof>107 n/(cm2 cdot s) at a distance of 2.5 m. The mechanical designand analysis of the four-module, bolt-together RFQ will be presentedhere. Operating at 200 MHz, the 5.1 m long RFQ will accelerate a 40 mAdeuteron beam to 6 MeV. At a 5 percent duty factor, the time-average d+beam current on target is 1.5 mA. Each of the 1.27 m long RFQ moduleswill consist of four solid OFHC copper vanes. A specially designed 3-DO-ring will provide vacuum sealing between both the vanes and themodules. RF connections are made with canted coil spring contacts. Aseries of 60 water-cooled pi-mode rods provides quadrupole modestabilization. A set of 80 evenly spaced fixed slug tuners is used forfinal frequency adjustment and local field perturbationcorrection.

  3. Neutronic and Physical Characteristics of an Accelerator Driven System with a Lead-208 Coolant

    SciTech Connect

    Khorasanov, Georgy L.; Ivonov, Anatoly P.; Blokhin, Anatoly I.

    2006-07-01

    In the paper a possibility of using a lead isotope, pure Pb-208, as a coolant for a subcritical core of 80 MW thermal capacity of the PDS-XADS type facility is considered. Calculations of neutronic characteristics were performed using Monte Carlo technique. The following initial data were chosen: an annular core with a target, as a neutron source, at its centre; the core coolant -- Pb-208 (100%); a fuel -- a mix of mono nitrides of depleted uranium and power plutonium with a small share of neptunium and americium; the target coolant -- a modified lead and bismuth eutectic, Pb-208(80%)-Bi(20%); proton beam energy -- 600 MeV; effective multiplication factor of the core under operation -- K{sub eff} = 0.97; thermal capacity of the core -- N = 80 MW. From calculations performed it follows that in using Pb-208 as the core coolant the necessary intensity of the external source of neutrons to deliver 80 MW thermal capacity is equal to S = 2.29-10{sup 17} n/s that corresponds to proton beam current I{sub p} = 2.8 mA and beam capacity P{sub p} 1.68 MW. In using natural lead instead of Pb-208 as the core coolant, effective multiplication factor of the core in normal operating regime falls down to the value equal to K{sub eff} = 0.95. In these conditions multiplication of external neutrons in the core and thermal capacity of the subcritical core are below nominal by 1.55 times. For achievement the rated core power N=80 MW it is required on {approx}20-30% to increase the fuel loading and volume of the core, or by 1.55 times to increase intensity of the external source of neutrons. In the last case, the required parameters of the neutron source and of the corresponding proton beam are following: intensity of the neutron source S = 3.55 10{sup 17} n/s., beam current I{sub p} = 4.32 mA, beam capacity P{sub p} 2.59 MW. To exploit the accelerator with the reduced proton beam current it will be required about 56 tons of Pb-208, as a minimum, for the core coolant. Charges for its

  4. Neutronics of accelerator-driven subcritical fission for burning transuranics in used nuclear fuel

    SciTech Connect

    Sattarov, A.; Assadi, S.; Badgley, K.; Baty, A.; Comeaux, J.; Gerity, J.; Kellams, J.; Mcintyre, P.; Pogue, N.; Sooby, E.; Tsvetkov, P.; Rosaire, G.; Mann, T.

    2013-04-19

    We report the development of a conceptual design for accelerator-driven subcritical fission in a molten salt core (ADSMS). ADSMS is capable of destroying all of the transuranics at the same rate and proportion as they are produced in a conventional nuclear power plant. The ADSMS core is fueled solely by transuranics extracted from used nuclear fuel and reduces its radiotoxicity by a factor 10,000. ADSMS offers a way to close the nuclear fuel cycle so that the full energy potential in the fertile fuels uranium and thorium can be recovered.

  5. Neutronics of accelerator-driven subcritical fission for burning transuranics in used nuclear fuel

    NASA Astrophysics Data System (ADS)

    Sattarov, A.; Assadi, S.; Badgley, K.; Baty, A.; Comeaux, J.; Gerity, J.; Kellams, J.; Mcintyre, P.; Pogue, N.; Sooby, E.; Tsvetkov, P.; Rosaire, G.; Mann, T.

    2013-04-01

    We report the development of a conceptual design for accelerator-driven subcritical fission in a molten salt core (ADSMS). ADSMS is capable of destroying all of the transuranics at the same rate and proportion as they are produced in a conventional nuclear power plant. The ADSMS core is fueled solely by transuranics extracted from used nuclear fuel and reduces its radiotoxicity by a factor 10,000. ADSMS offers a way to close the nuclear fuel cycle so that the full energy potential in the fertile fuels uranium and thorium can be recovered.

  6. Optimal moderator materials at various proton energies considering photon dose rate after irradiation for an accelerator-driven ⁹Be(p, n) boron neutron capture therapy neutron source.

    PubMed

    Hashimoto, Y; Hiraga, F; Kiyanagi, Y

    2015-12-01

    We evaluated the accelerator beam power and the neutron-induced radioactivity of (9)Be(p, n) boron neutron capture therapy (BNCT) neutron sources having a MgF2, CaF2, or AlF3 moderator and driven by protons with energy from 8 MeV to 30 MeV. The optimal moderator materials were found to be MgF2 for proton energies less than 10 MeV because of lower required accelerator beam power and CaF2 for higher proton energies because of lower photon dose rate at the treatment position after neutron irradiation. PMID:26272165

  7. Laser driven ion accelerator

    DOEpatents

    Tajima, Toshiki

    2006-04-18

    A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.

  8. Laser driven ion accelerator

    DOEpatents

    Tajima, Toshiki

    2005-06-14

    A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.

  9. Basic concept for an accelerator-driven subcritical system to be used as a long-pulse neutron source for Condensed Matter research

    NASA Astrophysics Data System (ADS)

    Vivanco, R.; Ghiglino, A.; de Vicente, J. P.; Sordo, F.; Terrón, S.; Magán, M.; Perlado, J. M.; Bermejo, F. J.

    2014-12-01

    A model for an accelerator-driven subcritical system to be operated as a source of cold neutrons for Condensed Matter research is developed at the conceptual level. Its baseline layout relies upon proven accelerator, spalattion target and fuel array technologies, and consists in a proton accelerator able to deliver some 67.5 mA of proton beam with kinetic energy 0.6 GeV, a pulse length of 2.86 ms, and repetition rate of 14 Hz. The particle beam hits a target of conventional design that is surrounded by a multiplicative core made of fissile/fertile material, composed by a subcritical array of fuel bars made of aluminium Cermet cooled by light water poisoned with boric acid. Relatively low enriched uranium is chosen as fissile material. An optimisation of several parameters is carried out, using as components of the objective function several characteristics pertaining the cold neutron pulse. The results show that the optimal device will deliver up to 80% of the cold neutron flux expected for some of the ongoing projects using a significantly lower proton beam power than that managed in such projects. The total power developed within the core rises up to 22.8 MW, and the criticality range shifts to a final keff value of around 0.9 after the 50 days cycle.

  10. Accelerator based epithermal neutron source

    NASA Astrophysics Data System (ADS)

    Taskaev, S. Yu.

    2015-11-01

    We review the current status of the development of accelerator sources of epithermal neutrons for boron neutron capture therapy (BNCT), a promising method of malignant tumor treatment. Particular attention is given to the source of epithermal neutrons on the basis of a new type of charged particle accelerator: tandem accelerator with vacuum insulation and lithium neutron-producing target. It is also shown that the accelerator with specialized targets makes it possible to generate fast and monoenergetic neutrons, resonance and monoenergetic gamma-rays, alpha-particles, and positrons.

  11. Accelerator driven sub-critical core

    DOEpatents

    McIntyre, Peter M; Sattarov, Akhdiyor

    2015-03-17

    Systems and methods for operating an accelerator driven sub-critical core. In one embodiment, a fission power generator includes a sub-critical core and a plurality of proton beam generators. Each of the proton beam generators is configured to concurrently provide a proton beam into a different area of the sub-critical core. Each proton beam scatters neutrons within the sub-critical core. The plurality of proton beam generators provides aggregate power to the sub-critical core, via the proton beams, to scatter neutrons sufficient to initiate fission in the sub-critical core.

  12. Accelerator driven assembly

    SciTech Connect

    Balderas, J.; Cappiello, M.; Cummings, C.E.; Davidson, R.

    1997-01-01

    This report addresses a Los Alamos National Laboratory (LANL) proposal to build a pulsed neutron source for simulating nuclear-weapons effects. A point design for the pulsed neutron facility was initiated early in FY94 after hosting a Defense Nuclear Agency (DNA) panel review and after subsequently visiting several potential clients and users. The technical and facility designs contained herein fulfill the Statement of Work (SOW) agreed upon by LANL and DNA. However, our point designs and parametric studies identify a unique, cost-effective, above-ground capability for neutron nuclear-weapons-effects studies at threat levels. This capability builds on existing capital installations and infrastructure at LANL. We believe that it is appropriate for us, together with the DNA, to return to the user community and ask for their comments and critiques. We also realize that the requirements of last year have changed significantly. Therefore, the present report is a `working document` that may be revised where feasible as we learn more about the most recent Department of Defense (DoD) and Department of Energy (DOE) needs.

  13. Fission fragment driven neutron source

    DOEpatents

    Miller, Lowell G.; Young, Robert C.; Brugger, Robert M.

    1976-01-01

    Fissionable uranium formed into a foil is bombarded with thermal neutrons in the presence of deuterium-tritium gas. The resulting fission fragments impart energy to accelerate deuterium and tritium particles which in turn provide approximately 14 MeV neutrons by the reactions t(d,n).sup.4 He and d(t,n).sup.4 He.

  14. Kinetics of accelerator driven devices

    SciTech Connect

    Perry, R.T.; Buksa, J.; Houts, M.

    1994-09-01

    Kinetic calculations were made to show that subcritical accelerator driven devices are robust and stable. The calculations show that large changes in reactivity that would lead to an uncontrollable excursion in a reactor would lead only to a new power level in subcritical device. Calculations were also made to show the rate of power changes resulting from startup and shutdown, and that methods also exist for continuously monitoring the reactivity of a subcritical system.

  15. Kinetics of accelerator driven devices

    SciTech Connect

    Perry, R. T.; Buksa, John; Houts, Michael

    1995-09-15

    Kinetic calculations were made to show that subcritical accelerator driven devices are robust and stable. The calculations show that large changes in reactivity that would lead to an uncontrollable excursion in a reactor would lead only to a new power level in a subcritical device. Calculations were also made to show the rate of power changes resulting from startup and shutdown, and that methods also exist for continuously monitoring the reactivity of a subcritical system.

  16. Accelerator-induced transients in Accelerator Driven Subcritical Reactors

    NASA Astrophysics Data System (ADS)

    Ahmad, Ali; Lindley, Benjamin A.; Parks, Geoffrey T.

    2012-12-01

    Achieving higher particles energies and beam powers have long been the main focus of research in accelerator technology. Since Accelerator Driven Subcritical Reactors (ADSRs) have become the subject of increasing interest, accelerator reliability and modes of operation have become important matters that require further research and development in order to accommodate the engineering and economic needs of ADSRs. This paper focuses on neutronic and thermo-mechanical analyses of accelerator-induced transients in an ADSR. Such transients fall into three main categories: beam interruptions (trips), pulsed-beam operation, and beam overpower. The concept of a multiple-target ADSR is shown to increase system reliability and to mitigate the negative effects of beam interruptions, such as thermal cyclic fatigue in the fuel cladding and the huge financial cost of total power loss. This work also demonstrates the effectiveness of the temperature-to-reactivity feedback mechanisms in ADSRs. A comparison of shutdown mechanisms using control rods and beam cut-off highlights the intrinsic safety features of ADSRs. It is evident that the presence of control rods is crucial in an industrial-scale ADSR. This paper also proposes a method to monitor core reactivity online using the repetitive pattern of beam current fluctuations in a pulsed-beam operation mode. Results were produced using PTS-ADS, a computer code developed specifically to study the dynamic neutronic and thermal responses to beam transients in subcritical reactor systems.

  17. Neutronics Study on Accelerator Driven Subcritical Systems with Thorium-Based Fuel for Comparison Between Solid and Molten-Salt Fuels

    SciTech Connect

    Ishimoto, Shunsuke; Ishibashi, Kenji; Tenzou, Hideki; Sasa, Toshinobu

    2002-06-15

    Since thorium is an abundant fertile material, there is hope for the thorium-cycle fuels for an accelerator driven subcritical system (ADS). The ADS utilizes neutrons, which are generated by high-energy protons of giga-electron-volt-grade, but cross sections for the interaction of high-energy particles are not available for use in current ADS engineering design. In this paper the neutron behavior in the ADS target based on the related experimental data is clarified, and the feasibility of the ADS regarding both the molten salts (Flibe: {sup 7}LiF-BeF{sub 2}-ThF{sub 4}-{sup 233}UF{sub 4}, chloride: NaCl-ThCl{sub 4}-{sup 233}UCl{sub 4}) and oxide ([Th, {sup 233}U]O{sub 2}) fuels is examined. The difference between the experiment and the calculated result at the ADS high-energy region is discussed. In a comparison of the fuels, the time evolution of k{sub eff} and the beam current in the burning period are calculated. The calculated results suggest that the ADS with solid fuel has better future prospects than that with molten-salt fuels. The ADS with Flibe molten-salt fuel tends to require a high beam current and consequently needs the installation of a metallic spallation target and the continuous removal for fission products and protactinium. In comparison with the Flibe fuel, the ADS with chloride fuel has a flux distribution that is similar to a solid fuel reactor.

  18. Accelerators and Neutron Capture Therapy

    NASA Astrophysics Data System (ADS)

    Burlon, A. A.; Kreiner, A. J.; Valda, A.

    2002-08-01

    Within the frame of Accelerator Based Boron Neutron Capture Therapy (AB-BNCT), the 7Li (p,n) 7Be reaction, relatively near its energy threshold is one of the most promising, due to its high yield and low neutron energy. In this work a thick LiF target irradiated with a proton beam was studied as a neutron source. The 1.88-2.0 MeV proton beam was produced by the tandem accelerator TANDAR at CNEA's facilities in Buenos Aires. A water-filled phantom, containing a boron sample was irradiated with the resulting neutron flux. The 10B(n,αγ)7Li boron neutron capture reaction produces a 0.478 MeV gamma ray in 94% of the cases. The neutron yield was measured through the detection of this gamma ray using a hyperpure germanium detector with an anti-Compton shield. In addition, the thermal neutron flux was evaluated at different depths inside the phantom using bare and Cd-covered gold foils. A maximum neutron thermal flux of 1.4×108 cm-2s-1mA-1 was obtained at 4.2 cm from the phantom surface. In order to optimize the design of the neutron production target and the beam shaping assembly extensive Monte Carlo Neutron and Photon (MCNP) simulations have been performed. Neutron fields from a thick LiF and a Li metal target (with both a D2O-graphite and a Al/AlF3-graphite moderator/reflector assembly) were evaluated along the centerline of a head and a whole body phantom. Simulations were carried out for 1.89, 2.0 and 2.3 MeV proton beams. The results show that it is more advantageous to irradiate the target with 2.3 MeV near-resonance protons, instead of very near threshold, because of the higher neutron yield at this energy. On the other hand, the Al/AlF3-graphite exhibits a more efficient performance than D2O in terms of tumor to maximum healthy tissue dose ratio. Treatment times of less than 15 min and tumor control probabilities larger than 98% are obtained for a 50 mA, 2.3 MeV proton beam. The alternative neutron-producing reaction 13C(d,n) is also briefly reviewed. A

  19. Linac-driven spallation-neutron source

    SciTech Connect

    Jason, A.J.

    1995-05-01

    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.

  20. Uncertainty assessment for accelerator-driven systems.

    SciTech Connect

    Finck, P. J.; Gomes, I.; Micklich, B.; Palmiotti, G.

    1999-06-10

    The concept of a subcritical system driven by an external source of neutrons provided by an accelerator ADS (Accelerator Driver System) has been recently revived and is becoming more popular in the world technical community with active programs in Europe, Russia, Japan, and the U.S. A general consensus has been reached in adopting for the subcritical component a fast spectrum liquid metal cooled configuration. Both a lead-bismuth eutectic, sodium and gas are being considered as a coolant; each has advantages and disadvantages. The major expected advantage is that subcriticality avoids reactivity induced transients. The potentially large subcriticality margin also should allow for the introduction of very significant quantities of waste products (minor Actinides and Fission Products) which negatively impact the safety characteristics of standard cores. In the U.S. these arguments are the basis for the development of the Accelerator Transmutation of Waste (ATW), which has significant potential in reducing nuclear waste levels. Up to now, neutronic calculations have not attached uncertainties on the values of the main nuclear integral parameters that characterize the system. Many of these parameters (e.g., degree of subcriticality) are crucial to demonstrate the validity and feasibility of this concept. In this paper we will consider uncertainties related to nuclear data only. The present knowledge of the cross sections of many isotopes that are not usually utilized in existing reactors (like Bi, Pb-207, Pb-208, and also Minor Actinides and Fission Products) suggests that uncertainties in the integral parameters will be significantly larger than for conventional reactor systems, and this raises concerns on the neutronic performance of those systems.

  1. Accelerator Driven Nuclear Energy: The Thorium Option

    ScienceCinema

    Raja, Rajendran

    2010-01-08

    Conventional nuclear reactors use enriched Uranium as fuel and produce nuclear waste which needs to be stored away for over 10,000 years.   At the current rate of use, existing sources of Uranium will last for 50-100 years.  We describe a solution to the problem that uses particle accelerators to produce fast neutrons that can be used to burn existing nuclear waste and produce energy.  Such systems, initially proposed by Carlo Rubbia and collaborators in the 1990's, are being seriously considered by many countries as a possible solution to the green energy problem.  Accelerator driven reactors operate in a sub-critical regime and, thus, are safer and can obtain energy from plentiful elements such as Thorium-232 and Uranium-238. What is missing is the high intensity (10MW) accelerator that produces 1 GeV protons. We will describe scenarios which if implemented will make such systems a reality.  

  2. A Bright Neutron Source Driven by a Short Pulse Laser

    NASA Astrophysics Data System (ADS)

    Roth, Markus

    2012-10-01

    Neutrons are a unique tool to alter and diagnose material properties, and to exciting nuclear reactions, for many applications. Accelerator based spallation sources provide high neutron fluxes for research, but there is a growing need for more compact sources with higher peak brightness, whether fast or moderated neutrons. Intense lasers promise such as source, readily linkable to other experimental facilities, or deployable outside a laboratory setting. We present experimental results on the first short-pulse laser-driven neutron source powerful enough for radiography. A novel laser-driven ion acceleration mechanism (Breakout Afterburner), operating in the relativistic transparency regime, is used. Based on the mechanism's advantages, a laser-driven deuteron beam is used to achieve a new record in laser-neutron production, in numbers, energy and directionality. This neutron beam is a highly directional pulse < 1 ns at ˜ 1 cm from the target, with a flux > 40/2̂, and thus suitable for imaging applications with high temporal resolution. The beam contained, for the first time, neutrons with energies of up to 150 MeV. Thus using short pulse lasers, it is now possible to use the resulting hard x-rays and neutrons of different energies to radiograph an unknown object and to determine its material composition. Our data matches the simulated data for our test samples.

  3. Terahertz-driven linear electron acceleration.

    PubMed

    Nanni, Emilio A; Huang, Wenqian R; Hong, Kyung-Han; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Miller, R J Dwayne; Kärtner, Franz X

    2015-01-01

    The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30-50 MeV m(-1) gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequency structures. However, laser-driven wakefield accelerators require intense femtosecond sources and direct laser-driven accelerators suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here we demonstrate linear acceleration of electrons with keV energy gain using optically generated terahertz pulses. Terahertz-driven accelerating structures enable high-gradient electron/proton accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. These ultra-compact terahertz accelerators with extremely short electron bunches hold great potential to have a transformative impact for free electron lasers, linear colliders, ultrafast electron diffraction, X-ray science and medical therapy with X-rays and electron beams. PMID:26439410

  4. Terahertz-driven linear electron acceleration

    SciTech Connect

    Nanni, Emilio A.; Huang, Wenqian R.; Hong, Kyung-Han; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Dwayne Miller, R. J.; Kärtner, Franz X.

    2015-10-06

    The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30–50 MeVm-1 gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequency structures. However, laser-driven wakefield accelerators require intense femtosecond sources and direct laser-driven accelerators suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here we demonstrate linear acceleration of electrons with keV energy gain using optically generated terahertz pulses. Terahertz-driven accelerating structures enable high-gradient electron/proton accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. As a result, these ultra-compact terahertz accelerators with extremely short electron bunches hold great potential to have a transformative impact for free electron lasers, linear colliders, ultrafast electron diffraction, X-ray science and medical therapy with X-rays and electron beams.

  5. Terahertz-driven linear electron acceleration

    PubMed Central

    Nanni, Emilio A.; Huang, Wenqian R.; Hong, Kyung-Han; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Dwayne Miller, R. J.; Kärtner, Franz X.

    2015-01-01

    The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30–50 MeV m−1 gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequency structures. However, laser-driven wakefield accelerators require intense femtosecond sources and direct laser-driven accelerators suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here we demonstrate linear acceleration of electrons with keV energy gain using optically generated terahertz pulses. Terahertz-driven accelerating structures enable high-gradient electron/proton accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. These ultra-compact terahertz accelerators with extremely short electron bunches hold great potential to have a transformative impact for free electron lasers, linear colliders, ultrafast electron diffraction, X-ray science and medical therapy with X-rays and electron beams. PMID:26439410

  6. Terahertz-driven linear electron acceleration

    NASA Astrophysics Data System (ADS)

    Nanni, Emilio A.; Huang, Wenqian R.; Hong, Kyung-Han; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Dwayne Miller, R. J.; Kärtner, Franz X.

    2015-10-01

    The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30-50 MeV m-1 gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequency structures. However, laser-driven wakefield accelerators require intense femtosecond sources and direct laser-driven accelerators suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here we demonstrate linear acceleration of electrons with keV energy gain using optically generated terahertz pulses. Terahertz-driven accelerating structures enable high-gradient electron/proton accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. These ultra-compact terahertz accelerators with extremely short electron bunches hold great potential to have a transformative impact for free electron lasers, linear colliders, ultrafast electron diffraction, X-ray science and medical therapy with X-rays and electron beams.

  7. Terahertz-driven linear electron acceleration

    DOE PAGESBeta

    Nanni, Emilio A.; Huang, Wenqian R.; Hong, Kyung-Han; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Dwayne Miller, R. J.; Kärtner, Franz X.

    2015-10-06

    The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30–50 MeVm-1 gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequency structures. However, laser-driven wakefield accelerators require intense femtosecond sources and direct laser-driven accelerators suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here we demonstrate linear acceleration of electrons with keV energy gain using optically generated terahertz pulses. Terahertz-driven accelerating structures enable high-gradient electron/proton acceleratorsmore » with simple accelerating structures, high repetition rates and significant charge per bunch. As a result, these ultra-compact terahertz accelerators with extremely short electron bunches hold great potential to have a transformative impact for free electron lasers, linear colliders, ultrafast electron diffraction, X-ray science and medical therapy with X-rays and electron beams.« less

  8. Mobile accelerator neutron radiography system

    NASA Astrophysics Data System (ADS)

    Dance, W. E.; Carollo, S. F.; Bumgardner, H. M.

    1984-10-01

    The use of neutron radiography for the inspection and maintenance of large structures such as aircraft has been delayed by the absence of a mobile system particularly suited to the requirements of field use. This report describes the production, extensive field testing, evaluation and disposition of the first mobile neutron radiography system to satisfy the majority of requirements for field use. The system is based upon the concept of a mobile on-off neutron radiography system based on a sealed-tube ion accelerator as neutron source demonstrated earlier by the Vought Corporation. Primary features of the system are its self-propelled mobility, versatile positioning capability scaled to Army helicopter dimensions, an on-off beam capability, exposure capability measured in minutes, and suitability for AMMRC laboratory and field use. Included in the report are a description of all components of the system, an evaluation of the operation of the system, an evaluation of its radiographic capabilities, a description of installation elements for the AMMRC site, and recommendations for next-generation systems.

  9. A bright neutron source driven by relativistic transparency of solids

    NASA Astrophysics Data System (ADS)

    Roth, M.; Jung, D.; Falk, K.; Guler, N.; Deppert, O.; Devlin, M.; Favalli, A.; Fernandez, J.; Gautier, D. C.; Geissel, M.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Johnson, R. P.; Kleinschmidt, A.; Merrill, F.; Schaumann, G.; Schoenberg, K.; Schollmeier, M.; Shimada, T.; Taddeucci, T.; Tybo, J. L.; Wagner, F.; Wender, S. A.; Wilde, C. H.; Wurden, G. A.

    2016-03-01

    Neutrons are a unique tool to alter and diagnose material properties and excite nuclear reactions with a large field of applications. It has been stated over the last years, that there is a growing need for intense, pulsed neutron sources, either fast or moderated neutrons for the scientific community. Accelerator based spallation sources provide unprecedented neutron fluxes, but could be complemented by novel sources with higher peak brightness that are more compact. Lasers offer the prospect of generating a very compact neutron source of high peak brightness that could be linked to other facilities more easily. We present experimental results on the first short pulse laser driven neutron source powerful enough for applications in radiography. For the first time an acceleration mechanism (BOA) based on the concept of relativistic transparency has been used to generate neutrons. This mechanism not only provides much higher particle energies, but also accelerated the entire target volume, thereby circumventing the need for complicated target treatment and no longer limited to protons as an intense ion source. As a consequence we have demonstrated a new record in laser-neutron production, not only in numbers, but also in energy and directionality based on an intense deuteron beam. The beam contained, for the first time, neutrons with energies in excess of 100 MeV and showed pronounced directionality, which makes then extremely useful for a variety of applications. The results also address a larger community as it paves the way to use short pulse lasers as a neutron source. They can open up neutron research to a broad academic community including material science, biology, medicine and high energy density physics as laser systems become more easily available to universities and therefore can complement large scale facilities like reactors or particle accelerators. We believe that this has the potential to increase the user community for neutron research largely.

  10. Progress of Laser-Driven Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Nakajima, Kazuhisa

    2007-07-01

    There is a great interest worldwide in plasma accelerators driven by ultra-intense lasers which make it possible to generate ultra-high gradient acceleration and high quality particle beams in a much more compact size compared with conventional accelerators. A frontier research on laser and plasma accelerators is focused on high energy electron acceleration and ultra-short X-ray and Tera Hertz radiations as their applications. These achievements will provide not only a wide range of sciences with benefits of a table-top accelerator but also a basic science with a tool of ultrahigh energy accelerators probing an unknown extremely microscopic world. Harnessing the recent advance of ultra-intense ultra-short pulse lasers, the worldwide research has made a tremendous breakthrough in demonstrating high-energy high-quality particle beams in a compact scale, so called "dream beams on a table top", which represents monoenergetic electron beams from laser wakefield accelerators and GeV acceleration by capillary plasma-channel laser wakefield accelerators. This lecture reviews recent progress of results on laser-driven plasma based accelerator experiments to quest for particle acceleration physics in intense laser-plasma interactions and to present new outlook for the GeV-range high-energy laser plasma accelerators.

  11. Progress of Laser-Driven Plasma Accelerators

    SciTech Connect

    Nakajima, Kazuhisa

    2007-07-11

    There is a great interest worldwide in plasma accelerators driven by ultra-intense lasers which make it possible to generate ultra-high gradient acceleration and high quality particle beams in a much more compact size compared with conventional accelerators. A frontier research on laser and plasma accelerators is focused on high energy electron acceleration and ultra-short X-ray and Tera Hertz radiations as their applications. These achievements will provide not only a wide range of sciences with benefits of a table-top accelerator but also a basic science with a tool of ultrahigh energy accelerators probing an unknown extremely microscopic world.Harnessing the recent advance of ultra-intense ultra-short pulse lasers, the worldwide research has made a tremendous breakthrough in demonstrating high-energy high-quality particle beams in a compact scale, so called ''dream beams on a table top'', which represents monoenergetic electron beams from laser wakefield accelerators and GeV acceleration by capillary plasma-channel laser wakefield accelerators. This lecture reviews recent progress of results on laser-driven plasma based accelerator experiments to quest for particle acceleration physics in intense laser-plasma interactions and to present new outlook for the GeV-range high-energy laser plasma accelerators.

  12. A Sealed-Accelerator-Tube Neutron Generator for Boron Neutron Capture Therapy Application

    SciTech Connect

    Leung, K.-N.; Leung, K.N.; Lee, Y.; Verbeke, J.M.; Vurjic, J.; Williams, M.D.; Wu, L.K.; Zahir, N.

    1998-06-01

    Radio-frequency (RF) driven ion sources are being developed in Lawrence Berkeley National Laboratory (LBNL) for sealed-accelerator-tube neutron generator applications. By using a 2.5-cm-diameter RF-driven multicusp source and a computer designed 100 keV accelerator column, peak extractable hydrogen current exceeding 1 A from a 3-mm-diameter aperture, together with H{sup +} yields over 94% have been achieved. These experimental findings together with recent moderator design will enable one to develop compact 14 MeV neutron generators based on the D-T fusion reaction. In this new neutron generator, the ion source, the accelerator and the target are all housed in a sealed metal container without pumping. With a 120 keV and 1 A deuteron beam, it is estimated that a treatment time of {approx} 45 minutes is needed for boron neutron capture therapy.

  13. Characterization of short-pulse laser driven neutron source

    NASA Astrophysics Data System (ADS)

    Falk, Katerina; Jung, Daniel; Guler, Nevzat; Deppert, Oliver; Devlin, Matthew; Fernandez, J. C.; Gautier, D. C.; Geissel, M.; Haight, R. C.; Hegelich, B. M.; Henzlova, Daniela; Ianakiev, K. D.; Iliev, Metodi; Johnson, R. P.; Merrill, F. E.; Schaumann, G.; Schoenberg, K.; Shimada, T.; Taddeucci, T. N.; Tybo, J. L.; Wagner, F.; Wender, S. A.; Wurden, G. A.; Favalli, Andrea; Roth, Markus

    2014-10-01

    We present a full spectral characterization of a novel laser driven neutron source, which employed the Break Out Afterburner ion acceleration mechanism. Neutrons were produced by nuclear reactions of the ions deposited on Be or Cu converters. We observed neutrons at energies up to 150 MeV. The neutron spectra were measured by five neutron time-of-flight detectors at various positions and distances from the source. The nTOF detectors observed that emission of neutrons is a superposition of an isotropic component peaking at 3.5--5 MeV resulting from nuclear reactions in the converter and a directional component at 25--70 MeV, which was a product of break-up reaction of the forward moving deuterons. Energy shifts due to geometrical effects in BOA were also observed.

  14. Technology of magnetically driven accelerators

    SciTech Connect

    Birx, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Rogers, D. Jr.; Smith, M.W.

    1985-03-26

    The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability. 8 figs., 1 tab.

  15. Technology of magnetically driven accelerators

    SciTech Connect

    Brix, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Smith, M.W.

    1985-10-01

    The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability.

  16. Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect

    Cowan, B.; /SLAC

    2005-09-19

    We discuss simulated photonic crystal structure designs for laser-driven particle acceleration, focusing on three-dimensional planar structures based on the so-called ''woodpile'' lattice. We demonstrate guiding of a speed-of-light accelerating mode by a defect in the photonic crystal lattice and discuss the properties of this mode. We also discuss particle beam dynamics in the structure, presenting a novel method for focusing the beam. In addition we describe some potential coupling methods for the structure.

  17. First neutron generation in the BINP accelerator based neutron source.

    PubMed

    Bayanov, B; Burdakov, A; Chudaev, V; Ivanov, A; Konstantinov, S; Kuznetsov, A; Makarov, A; Malyshkin, G; Mekler, K; Sorokin, I; Sulyaev, Yu; Taskaev, S

    2009-07-01

    Pilot innovative facility for neutron capture therapy was built at Budker Institute of Nuclear Physics, Novosibirsk. This facility is based on a compact vacuum insulation tandem accelerator designed to produce proton current up to 10 mA. Epithermal neutrons are proposed to be generated by 1.915 MeV protons bombarding a lithium target using (7)Li(p,n)(7)Be threshold reaction. The results of the first experiments on neutron generation are reported and discussed. PMID:19375928

  18. Accelerator requirements for fast-neutron interrogation of luggage and cargo

    SciTech Connect

    Micklich, B.J.; Fink, C.L.; Yule, T.J.

    1995-05-01

    Several different fast-neutron based techniques are being studied for the detection of contraband substances in luggage and cargo containers. The present work discusses the accelerator requirements for fast-neutron transmission spectroscopy (FNTS), pulsed fast-neutron analysis (PFNA), and 14-MeV neutron interrogation. These requirements are based on the results of Monte-Carlo simulations of neutron or gamma detection rates. Accelerator requirements are driven by count-rate considerations, spatial resolution and acceptable uncertainties in elemental compositions. The authors have limited their analyses to luggage inspection with FNTS and to cargo inspection with PFNA or 14-MeV neutron interrogation.

  19. Concept of an accelerator-driven subcritical research reactor within the TESLA accelerator installation

    NASA Astrophysics Data System (ADS)

    Pešić, Milan; Nešković, Nebojša

    2006-06-01

    Study of a small accelerator-driven subcritical research reactor in the Vinča Institute of Nuclear Sciences was initiated in 1999. The idea was to extract a beam of medium-energy protons or deuterons from the TESLA accelerator installation, and to transport and inject it into the reactor. The reactor core was to be composed of the highly enriched uranium fuel elements. The reactor was designated as ADSRR-H. Since the use of this type of fuel elements was not recommended any more, the study of a small accelerator-driven subcritical research reactor employing the low-enriched uranium fuel elements began in 2004. The reactor was designated as ADSRR-L. We compare here the results of the initial computer simulations of ADSRR-H and ADSRR-L. The results have confirmed that our concept could be the basis for designing and construction of a low neutron flux model of the proposed accelerator-driven subcritical power reactor to be moderated and cooled by lead. Our objective is to study the physics and technologies necessary to design and construct ADSRR-L. The reactor would be used for development of nuclear techniques and technologies, and for basic and applied research in neutron physics, metrology, radiation protection and radiobiology.

  20. Ultra-bright laser-driven neutron source

    NASA Astrophysics Data System (ADS)

    Roth, M.; Favalli, A.; Bagnoud, V.; Bridgewater, J.; Deppert, O.; Devlin, M.; Falk, K.; Fernndez, J.; Gautier, D.; Guler, N.; Henzlova, D.; Hornung, J.; Iliev, M.; Ianakiev, K.; Kleinschmidt, A.; Koehler, K.; Palaniyappan, S.; Poth, P.; Schaumann, G.; Swinhoe, M.; Taddeucci, T.; Tebartz, A.; Wagner, Florian; Wurden, G.

    2015-11-01

    Short-pulse laser-driven neutron sources have become a topic of interest since their brightness and yield have recently increased by orders of magnitude. Using novel target designs, high contrast - high power lasers and compact converter/moderator setups, these neutron sources have finally reached intensities that make many interesting applications possible. We present the results of two experimental campaigns on the GSI PHELIX and the LANL Trident lasers from 2015. We have produced an unprecedented neutron flux, mapped the spatial distribution of the neutron production as well as its energy spectra and ultimately used the beam for first applications to show the prospect of these new compact sources. We also made measurements for the conversion of energetic neutrons into short epithermal and thermal neutron pulses in order to evaluate further applications in dense plasma research. The results address a large community as it paves the way to use short pulse lasers as a neutron source. This can open up neutron research to a broad academic community including material science, biology, medicine and high energy density physics to universities and therefore can complement large scale facilities like reactors or particle accelerators.

  1. ACCELERATOR BASED CONTINUOUS NEUTRON SOURCE.

    SciTech Connect

    SHAPIRO,S.M.; RUGGIERO,A.G.; LUDEWIG,H.

    2003-03-25

    Until the last decade, most neutron experiments have been performed at steady-state, reactor-based sources. Recently, however, pulsed spallation sources have been shown to be very useful in a wide range of neutron studies. A major review of neutron sources in the US was conducted by a committee chaired by Nobel laureate Prof. W. Kohn: ''Neutron Sources for America's Future-BESAC Panel on Neutron Sources 1/93''. This distinguished panel concluded that steady state and pulsed sources are complementary and that the nation has need for both to maintain a balanced neutron research program. The report recommended that both a new reactor and a spallation source be built. This complementarity is recognized worldwide. The conclusion of this report is that a new continuous neutron source is needed for the second decade of the 20 year plan to replace aging US research reactors and close the US neutron gap. it is based on spallation production of neutrons using a high power continuous superconducting linac to generate protons impinging on a heavy metal target. There do not appear to be any major technical challenges to the building of such a facility since a continuous spallation source has been operating in Switzerland for several years.

  2. New options for developing of nuclear energy using an accelerator-driven reactor

    SciTech Connect

    Takahashi, Hiroshi

    1997-09-01

    Fissile fuel can be produced at a high rate using an accelerator-driven Pu-fueled subcritical fast reactor. Thus, the necessity of early introduction of the fast reactor can be moderated. High reliability of the proton accelerator, which is essential to implementing an accelerator-driven reactor in the nuclear energy field can be achieved by a slight extension of the accelerator`s length, with only a small economical penalty. Subcritical operation provides flexible nuclear energy options including high neutron economy producing the fuel, transmuting high-level wastes, such as minor actinides, and of converting efficiently the excess Pu and military Pu into proliferation-resistant fuel.

  3. An Accelerator Neutron Source for BNCT

    SciTech Connect

    Blue, Thomas, E

    2006-03-14

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

  4. Arc-driven rail accelerator research

    NASA Technical Reports Server (NTRS)

    Ray, Pradosh K.

    1987-01-01

    Arc-driven rail accelerator research is analyzed by considering wall ablation and viscous drag in the plasma. Plasma characteristics are evaluated through a simple fluid-mechanical analysis considering only wall ablation. By equating the energy dissipated in the plasma with the radiation heat loss, the average properties of the plasma are determined as a function of time and rate of ablation. Locations of two simultaneously accelerating arcs were determined by optical and magnetic probes and fron streak camera photographs. All three measurements provide consistent results.

  5. Neutrino physics with accelerator driven subcritical reactors

    NASA Astrophysics Data System (ADS)

    Ciuffoli, Emilio; Evslin, Jarah; Zhao, Fengyi

    2016-01-01

    Accelerator driven system (ADS) subcritical nuclear reactors are under development around the world. They will be intense sources of free, 30-55 MeV μ + decay at rest {overline{ν}}_{μ } . These ADS reactor neutrinos can provide a robust test of the LSND anomaly and a precise measurement of the leptonic CP-violating phase δ, including sign(cos(δ)). The first phase of many ADS programs includes the construction of a low energy, high intensity proton or deuteron accelerator, which can yield competitive bounds on sterile neutrinos.

  6. BINP accelerator based epithermal neutron source.

    PubMed

    Aleynik, V; Burdakov, A; Davydenko, V; Ivanov, A; Kanygin, V; Kuznetsov, A; Makarov, A; Sorokin, I; Taskaev, S

    2011-12-01

    Innovative facility for neutron capture therapy has been built at BINP. This facility is based on compact vacuum insulation tandem accelerator designed to produce proton current up to 10 mA. Epithermal neutrons are proposed to be generated by 1.915-2.5 MeV protons bombarding a lithium target using (7)Li(p,n)(7)Be threshold reaction. In the article, diagnostic techniques for proton beam and neutrons developed are described, results of experiments on proton beam transport and neutron generation are shown, discussed, and plans are presented. PMID:21439836

  7. An accelerator-driven reactor for meeting future energy demand

    SciTech Connect

    Takahashi, Hiroshi; Yang, Y.; Yu, A.

    1997-12-31

    Fissile fuel can be produced at a high rate using an accelerator-driven Pu-fueled subcritical fast reactor which avoids encountering a shortage of Pu during a high growth rate in the production of nuclear energy. Furthermore, the necessity of the early introduction of the fast reactor can be moderated. Subcritical operation provides flexible nuclear energy options along with high neutron economy for producing the fuel, for transmuting high-level waste such as minor actinides, and for efficiently converting excess and military Pu into proliferation-resistant fuel.

  8. Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect

    Cowan, Benjamin M.

    2007-08-22

    Laser-driven acceleration holds great promise for significantly improving accelerating gradient. However, scaling the conventional process of structure-based acceleration in vacuum down to optical wavelengths requires a substantially different kind of structure. We require an optical waveguide that (1) is constructed out of dielectric materials, (2) has transverse size on the order of a wavelength, and (3) supports a mode with speed-of-light phase velocity in vacuum. Photonic crystals---structures whose electromagnetic properties are spatially periodic---can meet these requirements. We discuss simulated photonic crystal accelerator structures and describe their properties. We begin with a class of two-dimensional structures which serves to illustrate the design considerations and trade-offs involved. We then present a three-dimensional structure, and describe its performance in terms of accelerating gradient and efficiency. We discuss particle beam dynamics in this structure, demonstrating a method for keeping a beam confined to the waveguide. We also discuss material and fabrication considerations. Since accelerating gradient is limited by optical damage to the structure, the damage threshold of the dielectric is a critical parameter. We experimentally measure the damage threshold of silicon for picosecond pulses in the infrared, and determine that our structure is capable of sustaining an accelerating gradient of 300 MV/m at 1550 nm. Finally, we discuss possibilities for manufacturing these structures using common microfabrication techniques.

  9. Crystal Driven Neutron Source: A New Paradigm for Miniature Neutron Sources

    SciTech Connect

    Tang, V; Morse, J; Meyer, G; Falabella, S; Guethlein, G; Kerr, P; Park, H G; Rusnak, B; Sampayan, S; Schmid, G; Spadaccini, C; Wang, L

    2008-08-08

    Neutron interrogation techniques have specific advantages for detection of hidden, shielded, or buried threats over other detection modalities in that neutrons readily penetrate most materials providing backscattered gammas indicative of the elemental composition of the potential threat. Such techniques have broad application to military and homeland security needs. Present neutron sources and interrogation systems are expensive and relatively bulky, thereby making widespread use of this technique impractical. Development of a compact, high intensity crystal driven neutron source is described. The crystal driven neutron source approach has been previously demonstrated using pyroelectric crystals that generate extremely high voltages when thermal cycled [1-4]. Placement of a sharpened needle on the positively polarized surface of the pyroelectric crystal results in sufficient field intensification to field ionize background deuterium molecules in a test chamber, and subsequently accelerate the ions to energies in excess of {approx}100 keV, sufficient for either D-D or D-T fusion reactions with appropriate target materials. Further increase in ion beam current can be achieved through optimization of crystal thermal ramping, ion source and crystal accelerator configuration. The advantage of such a system is the compact size along with elimination of large, high voltage power supplies. A novel implementation discussed incorporates an independently controlled ion source in order to provide pulsed neutron operation having microsecond pulse width.

  10. Crystal Driven Neutron Source: A New Paradigm for Miniature Neutron Sources

    NASA Astrophysics Data System (ADS)

    Tang, V.; Morse, J.; Meyer, G.; Falabella, S.; Guethlein, G.; Kerr, P.; Park, H. G.; Rusnak, B.; Sampayan, S.; Schmid, G.; Spadaccini, C.; Wang, L.

    2009-03-01

    Neutron interrogation techniques have specific advantages for detection of hidden, shielded, or buried threats over other detection modalities in that neutrons readily penetrate most materials providing backscattered gammas indicative of the elemental composition of the potential threat. Such techniques have broad application to military and homeland security needs. Present neutron sources and interrogation systems are expensive and relatively bulky, thereby making widespread use of this technique impractical. Development of a compact, high intensity crystal driven neutron source is described. The crystal driven neutron source approach has been previously demonstrated using pyroelectric crystals that generate extremely high voltages when thermal cycled [1-4]. Placement of a sharpened needle on the positively polarized surface of the pyroelectric crystal results in sufficient field intensification to field ionize background deuterium molecules in a test chamber, and subsequently accelerate the ions to energies in excess of ˜100 keV, sufficient for either D-D or D-T fusion reactions with appropriate target materials. Further increase in ion beam current can be achieved through optimization of crystal thermal ramping, ion source and crystal accelerator configuration. The advantage of such a system is the compact size along with elimination of large, high voltage power supplies. A novel implementation discussed incorporates an independently controlled ion source in order to provide pulsed neutron operation having microsecond pulse width.

  11. Observation of Neutron Skyshine from an Accelerator Based Neutron Source

    SciTech Connect

    Franklyn, C. B.

    2011-12-13

    A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >10{sup 11} n{center_dot}s{sup -1}. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.

  12. Observation of Neutron Skyshine from an Accelerator Based Neutron Source

    NASA Astrophysics Data System (ADS)

    Franklyn, C. B.

    2011-12-01

    A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >1011 nṡs-1. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.

  13. The Spallation Neutron Source accelerator system design

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  14. Accelerator-driven X-ray Sources

    SciTech Connect

    Nguyen, Dinh Cong

    2015-11-09

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

  15. Accelerator based epithermal neutron source for neutron capture therapy

    SciTech Connect

    Brugger, R.; Kunze, J.

    1991-05-01

    Several investigators have suggested that a charged particle accelerator with light element reactions might be able to produce enough epithermal neutrons to be useful in Neutron Capture Therapy. The reaction choice so far has been the Li(p,n) reaction with protons up to 2.5 MeV. A moderator around the target would reduce the faster neutrons down to the epithermal energy region. The goals of the present research are: identify better reactions; improve the moderators; and find better combinations of 1 and 2. The target is to achieve, at the patient location, an epithermal neutron current of greater than 10{sup 9}n/cm{sup 2}sec, with a dose to tissue from the neutrons alone of less than 10{sup {minus}10} rads/n and a dose from the gamma rays in the beam of less than 10{sup {minus}10} rads/n.

  16. Optimization of accelerator-driven technology for LWR waste transmutation

    SciTech Connect

    Bowman, C.D.

    1996-12-31

    The role of accelerator-driven transmutation technology is examined in the context of the destruction of actinide waste from commercial light water reactors. It is pointed out that the commercial plutonium is much easier to use for entry-level nuclear weapons than weapons plutonium. Since commercial plutonium is easier to use, since there is very much more of it already, and since it is growing rapidly, the permanent disposition of commercial plutonium is an issue of greater importance than weapons plutonium. The minor actinides inventory, which may be influenced by transmutation, is compared in terms of nuclear properties with commercial and weapons plutonium and for possible utility as weapons material. Fast and thermal spectrum systems are compared as means for destruction of plutonium and the minor actinides. it is shown that the equilibrium fast spectrum actinide inventory is about 100 times larger than for thermal spectrum systems, and that there is about 100 times more weapons-usable material in the fast spectrum system inventory compared to the thermal spectrum system. Finally it is shown that the accelerator size for transmutation can be substantially reduced by design which uses the accelerator-produced neutrons only to initiate the unsustained fission chains characteristic of the subcritical system. The analysis argues for devoting primary attention to the development of thermal spectrum transmutation technology. A thermal spectrum transmuter operating at a fission power of 750-MWth fission power, which is sufficient to destroy the actinide waste from one 3,000-MWth light water reactor, may be driven by a proton beam of 1 GeV energy and a current of 7 mA. This accelerator is within the range of realizable cyclotron technology and is also near the size contemplated for the next generation spallation neutron source under consideration by the US, Europe, and Japan.

  17. Accelerator shield design of KIPT neutron source facility

    SciTech Connect

    Zhong, Z.; Gohar, Y.

    2013-07-01

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

  18. Plasma driven neutron/gamma generator

    DOEpatents

    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. PRODUCTION AND APPLICATIONS OF NEUTRONS USING PARTICLE ACCELERATORS

    SciTech Connect

    David L. Chichester

    2009-11-01

    Advances in neutron science have gone hand in hand with the development and of particle accelerators from the beginning of both fields of study. Early accelerator systems were developed simply to produce neutrons, allowing scientists to study their properties and how neutrons interact in matter, but people quickly realized that more tangible uses existed too. Today the diversity of applications for industrial accelerator-based neutron sources is high and so to is the actual number of instruments in daily use is high, and they serve important roles in the fields where they're used. This chapter presents a technical introduction to the different ways particle accelerators are used to produce neutrons, an historical overview of the early development of neutron-producing particle accelerators, a description of some current industrial accelerator systems, narratives of the fields where neutron-producing particle accelerators are used today, and comments on future trends in the industrial uses of neutron producing particle accelerators.

  20. Accelerating Science Driven System Design With RAMP

    SciTech Connect

    Wawrzynek, John

    2015-05-01

    Researchers from UC Berkeley, in collaboration with the Lawrence Berkeley National Lab, are engaged in developing an Infrastructure for Synthesis with Integrated Simulation (ISIS). The ISIS Project was a cooperative effort for “application-driven hardware design” that engages application scientists in the early parts of the hardware design process for future generation supercomputing systems. This project served to foster development of computing systems that are better tuned to the application requirements of demanding scientific applications and result in more cost-effective and efficient HPC system designs. In order to overcome long conventional design-cycle times, we leveraged reconfigurable devices to aid in the design of high-efficiency systems, including conventional multi- and many-core systems. The resulting system emulation/prototyping environment, in conjunction with the appropriate intermediate abstractions, provided both a convenient user programming experience and retained flexibility, and thus efficiency, of a reconfigurable platform. We initially targeted the Berkeley RAMP system (Research Accelerator for Multiple Processors) as that hardware emulation environment to facilitate and ultimately accelerate the iterative process of science-driven system design. Our goal was to develop and demonstrate a design methodology for domain-optimized computer system architectures. The tangible outcome is a methodology and tools for rapid prototyping and design-space exploration, leading to highly optimized and efficient HPC systems.

  1. Accelerator-based neutron radioscopic systems

    NASA Astrophysics Data System (ADS)

    Berger, Harold; Dance, William E.

    1999-06-01

    There is interest in non-reactor source, thermal neutron inspection systems for applications in aircraft maintenance, explosive devices, investment-cast turbine blades, etc. Accelerator sources, (d-T), RFQ accelerators and cyclotrons as examples, are available for either transportable or fixed neutron inspection systems. Sources are reviewed for neutron output, portability, ease of use and cost, and for use with an electronic neutron imaging camera (image intensifier or scintillator-camera system) to provide a prompt response, neutron inspection system. Particular emphasis is given to the current aircraft inspection problem to detect and characterize corrosion. Systems are analyzed to determine usefulness in providing an on-line inspection technique to detect corrosion in aluminum honeycomb aircraft components, either on-aircraft or in a shop environment. The neutron imaging sensitivity to hydrogenous aluminum corrosion product offers early detection advantages for aircraft corrosion, to levels of aluminum metal loss as small as 25 μm. The practical capability for a continuous scan thermal neutron radioscopic system to inspect up to 500 square feet of component surface per day is used as an evaluation criterion, with the system showing contrast sensitivity of at least 5% and image detail in the order of 4 mm for parts 10 cm thick. Under these practical conditions and 3-shift operation, the source must provide an incident thermal neutron flux of 5.6×104n cm-2 s-1 at an L/D of 30. A stop and go inspection approach, offering improved resolution, would require a source with similar characteristics.

  2. Electron accelerator-driven photoneutron source for clinical environments

    NASA Astrophysics Data System (ADS)

    Dale, Gregory Edward

    There are several potential uses for a high-flux thermal neutron source in both industrial and clinical applications. The viable commercial implementation of these applications requires a low cost, high-flux thermal neutron generator suitable for installation in industrial and clinical environments. This dissertation describes the MCNP modeling results of a high-flux thermal neutron source driven with an electron accelerator. An electron linac, fitted with a standard x-ray converter, can produce high neutron yields in materials with low photonuclear threshold energies, such as D and 9Be. Calculations were performed using the Monte Carlo for N-Particle (MCNP) transport code. Modeling results indicate that a 10 MeV, 10 kW electron linac can produce on the order of 1012 n/s in a heavy water photoneutron target. A 40 cm radius, 60 cm long cylindrical heavy water photoneutron target has a photoneutron production rate equal to 5.7 x 1012 n/s. The thermal neutron flux in an unreflected, 40 cm radius, 60 cm long heavy water target is calculated to be 9.81 x 109 n/cm 2/s. The sensitivity of these answers to heavy water purity was investigated, specifically, the dilution of heavy water with light water. It was shown that the peak thermal neutron flux in an unreflected target was not adversely effected by dilution up to a light water weight fraction of 25%. The final design consists of a 40 cm radius, 60 cm long cylindrical photonuclear target reflected on all sides with 20 cm of polyethylene. The polyethylene reflector increases the maximum thermal neutron flux by 66%, to 1.40 x 1010 n/cm2/s using a 10 MeV, 1 mA (10 kW) electron linac. At this flux level the device is capable of producing 831 muCi/mg of 165Dy from natural dysprosium. The device is capable of producing 160 muCi/mg of 198Au at this flux. The neutron shielding required for the device consists of 5 cm of 5% borated polyethylene (BPE) on the front of the device, 4.25 cm of BPE on the side, and 8.5 cm of BPE on

  3. Accelerator Based Neutron Beams for Neutron Capture Therapy

    SciTech Connect

    Yanch, Jacquelyn C.

    2003-04-11

    The DOE-funded accelerator BNCT program at the Massachusetts Institute of Technology has resulted in the only operating accelerator-based epithermal neutron beam facility capable of generating significant dose rates in the world. With five separate beamlines and two different epithermal neutron beam assemblies installed, we are currently capable of treating patients with rheumatoid arthritis in less than 15 minutes (knee joints) or 4 minutes (finger joints) or irradiating patients with shallow brain tumors to a healthy tissue dose of 12.6 Gy in 3.6 hours. The accelerator, designed by Newton scientific Incorporated, is located in dedicated laboratory space that MIT renovated specifically for this project. The Laboratory for Accelerator Beam Applications consists of an accelerator room, a control room, a shielded radiation vault, and additional laboratory space nearby. In addition to the design, construction and characterization of the tandem electrostatic accelerator, this program also resulted in other significant accomplishments. Assemblies for generating epithermal neutron beams were designed, constructed and experimentally evaluated using mixed-field dosimetry techniques. Strategies for target construction and target cooling were implemented and tested. We demonstrated that the method of submerged jet impingement using water as the coolant is capable of handling power densities of up to 6 x 10(sup 7) W/m(sup 2) with heat transfer coefficients of 10(sup 6)W/m(sup 2)-K. Experiments with the liquid metal gallium demonstrated its superiority compared with water with little effect on the neutronic properties of the epithermal beam. Monoenergetic proton beams generated using the accelerator were used to evaluate proton RBE as a function of LET and demonstrated a maximum RBE at approximately 30-40 keV/um, a finding consistent with results published by other researchers. We also developed an experimental approach to biological intercomparison of epithermal beams and

  4. Electron versus proton accelerator driven sub-critical system performance using TRIGA reactors at power

    SciTech Connect

    Carta, M.; Burgio, N.; D'Angelo, A.; Santagata, A.; Petrovich, C.; Schikorr, M.; Beller, D.; Felice, L. S.; Imel, G.; Salvatores, M.

    2006-07-01

    This paper provides a comparison of the performance of an electron accelerator-driven experiment, under discussion within the Reactor Accelerator Coupling Experiments (RACE) Project, being conducted within the U.S. Dept. of Energy's Advanced Fuel Cycle Initiative (AFCI), and of the proton-driven experiment TRADE (TRIGA Accelerator Driven Experiment) originally planned at ENEA-Casaccia in Italy. Both experiments foresee the coupling to sub-critical TRIGA core configurations, and are aimed to investigate the relevant kinetic and dynamic accelerator-driven systems (ADS) core behavior characteristics in the presence of thermal reactivity feedback effects. TRADE was based on the coupling of an upgraded proton cyclotron, producing neutrons via spallation reactions on a tantalum (Ta) target, with the core driven at a maximum power around 200 kW. RACE is based on the coupling of an Electron Linac accelerator, producing neutrons via photoneutron reactions on a tungsten-copper (W-Cu) or uranium (U) target, with the core driven at a maximum power around 50 kW. The paper is focused on analysis of expected dynamic power response of the RACE core following reactivity and/or source transients. TRADE and RACE target-core power coupling coefficients are compared and discussed. (authors)

  5. Radiological Hazard of Spallation Products in Accelerator-Driven System

    SciTech Connect

    Saito, M.; Stankovskii, A.; Artisyuk, V.; Korovin, Yu.; Shmelev, A.; Titarenko, Yu.

    2002-09-15

    The central issue underlying this paper is related to elucidating the hazard of radioactive spallation products that might be an important factor affecting the design option of accelerator-driven systems (ADSs). Hazard analysis based on the concept of Annual Limit on Intake identifies alpha-emitting isotopes of rare earths (REs) (dysprosium, gadolinium, and samarium) as the dominant contributors to the overall toxicity of traditional (W, Pb, Pb-Bi) targets. The matter is addressed from several points of view: code validation to simulate their yields, choice of material for the neutron producing targets, and challenging the beam type. The paper quantitatively determines the domain in which the toxicity of REs exceeds that of polonium activation products broadly discussed now in connection with advertising lead-bismuth technology for the needs of ADSs.

  6. Technologies using accelerator-driven targets under development at BNL

    SciTech Connect

    Van Tuyle, G.J.

    1994-08-01

    Recent development work conducted at Brookhaven National Laboratory on technologies which use particle accelerator-driven targets is summarized. These efforts include development of the Spallation-Induced Lithium Conversion (SILC) Target for the Accelerator Production of Tritium (APT), the Accelerator-Driven Assembly for Plutonium Transformation (ADAPT) Target for the Accelerator-Based Conversion (ABC) of excess weapons plutonium. The PHOENIX Concept for the accelerator-driven transmutation of minor actinides and fission products from the waste stream of commercial nuclear power plants, and other potential applications.

  7. Accelerator-driven Transmutation of Waste

    NASA Astrophysics Data System (ADS)

    Venneri, Francesco

    1998-04-01

    Nuclear waste from commercial power plants contains large quantities of plutonium, other fissionable actinides, and long-lived fission products that are potential proliferation concerns and create challenges for the long-term storage. Different strategies for dealing with nuclear waste are being followed by various countries because of their geologic situations and their views on nuclear energy, reprocessing and non-proliferation. The current United States policy is to store unprocessed spent reactor fuel in a geologic repository. Other countries are opting for treatment of nuclear waste, including partial utilization of the fissile material contained in the spent fuel, prior to geologic storage. Long-term uncertainties are hampering the acceptability and eventual licensing of a geologic repository for nuclear spent fuel in the US, and driving up its cost. The greatest concerns are with the potential for radiation release and exposure from the spent fuel for tens of thousands of years and the possible diversion and use of the actinides contained in the waste for weapons construction. Taking advantage of the recent breakthroughs in accelerator technology and of the natural flexibility of subcritical systems, the Accelerator-driven Transmutation of Waste (ATW) concept offers the United States and other countries the possibility to greatly reduce plutonium, higher actinides and environmentally hazardous fission products from the waste stream destined for permanent storage. ATW does not eliminate the need for, but instead enhances the viability of permanent waste repositories. Far from being limited to waste destruction, the ATW concept also brings to the table new technologies that could be relevant for next-generation power producing reactors. In the ATW concept, spent fuel would be shipped to the ATW site where the plutonium, transuranics and selected long-lived fission products would be destroyed by fission or transmutation in their first and only pass through the

  8. Proton acceleration in neutron star magnetospheres

    NASA Technical Reports Server (NTRS)

    Smith, I. A.; Katz, J. I.; Diamond, P. H.

    1992-01-01

    To explain the emission of TeV and PeV gamma rays from accreting X-ray binary sources, protons must be accelerated to several times the gamma-ray energy. It is shown here that at certain times, the plasma in the accretion column of the neutron star may form a deep enough pool that the top portion becomes unstable to convective motions in spite of the strong magnetic field. The resulting turbulence produces fluctuations in the strength of the magnetic field that travel up the accretion column, taking energy out to the region of the energetic protons. The protons resonantly absorb this energy and are accelerated to high energies. Including the synchrotron radiation losses of the protons, it is shown that they can be accelerated to energies that are high enough to explain the gamma-ray observations.

  9. Laser Acceleration of Ultrashort Ion Bunches and Femtosecond Neutron Sources

    SciTech Connect

    Macchi, A.; Cattani, F.; Liseykina, T. V.; Cornolti, F.

    2006-04-07

    We have theoretically investigated the acceleration of ions in the interaction of high intensity, circularly polarized laser pulses with overdense plasmas. By using 1D and 2D particle-in-cell (PIC) simulations we find that high-density, short duration ion bunches moving into the plasma are promptly generated at the laser-plasma interaction surface. This regime is qualitatively different from ion acceleration regimes driven by fast electrons, such as sheath acceleration at the back of the target or shock acceleration at the front, which occur for linear polarization. A simple analytical model accounts for the numerical observations and provides scaling laws for the ion bunch velocity and generation time as a function of pulse intensity and plasma density. The present mechanism based on circular polarization of the laser pulse leads to moderate ion energies (in the 100 keV-1 MeV range) but very high ion densities and low beam divergence. These ion bunches might be of interest for problems of compression and acceleration of high-density matter by short pulses as well as for the development of compact neutron sources. We analyzed a scheme based on two-side irradiation of a thin foil deuterated target, where two colliding ion bunches are produced leading to an ultrashort neutron burst. We evaluated that, for intensities of a few 1019 W cm-2, more than 103 neutrons per Joule may be produced within a time shorter than one femtosecond. Another scheme based on a layered deuterium-tritium target is outlined.

  10. Designing accelerator-based epithermal neutron beams for boron neutron capture therapy

    SciTech Connect

    Bleuel, D.L.; Donahue, R.J.; Ludewigt, B.A.; Vujic, J.

    1998-09-01

    The {sup 7}Li(p,n){sup 7}Be reaction has been investigated as an accelerator-driven neutron source for proton energies between 2.1 and 2.6 MeV. Epithermal neutron beams shaped by three moderator materials, Al/AlF{sub 3}, {sup 7}LiF, and D{sub 2}O, have been analyzed and their usefulness for boron neutron capture therapy (BNCT) treatments evaluated. Radiation transport through the moderator assembly has been simulated with the Monte Carlo {ital N}-particle code (MCNP). Fluence and dose distributions in a head phantom were calculated using BNCT treatment planning software. Depth-dose distributions and treatment times were studied as a function of proton beam energy and moderator thickness. It was found that an accelerator-based neutron source with Al/AlF{sub 3} or {sup 7}LiF as moderator material can produce depth-dose distributions superior to those calculated for a previously published neutron beam design for the Brookhaven Medical Research Reactor, achieving up to {approximately}50{percent} higher doses near the midline of the brain. For a single beam treatment, a proton beam current of 20 mA, and a {sup 7}LiF moderator, the treatment time was estimated to be about 40 min. The tumor dose deposited at a depth of 8 cm was calculated to be about 21 Gy-Eq. {copyright} {ital 1998 American Association of Physicists in Medicine.}

  11. Acceleration efficiency in line-driven flows

    NASA Technical Reports Server (NTRS)

    Gayley, Kenneth G.; Owocki, Stanley P.

    1994-01-01

    We reexamine the physics of flow driving by line scattering of a continuum radiation source to determine the degree to which such line scattering can heat as well as accelerate the flow. Within the framework of the Sobolev theory for line transfer, we argue that the finite thermal width of the line scattering profile can lead to a significant 'Doppler heating' via photon frequency redistribution within a Sobolev resonance layer. Quantitative computation of this heating shows, however, that it is largely canceled by a corresponding cooling by the diffuse radiation. The resulting reduction in net Doppler heating or cooling means that the overall effect is only of limited importance in the energy balance of line-driven stellar winds. Through simple scaling relations, we compare the effect to other competing heating or cooling terms, including the ion-drag frictional heating recently discussed by Springmann and Pauldrach. We also provide a physical explanation of the unexpected cooling effect, and comment that its near cancellation of the anticipated heating provides another example of the tendency for ideal Sobolev theory to apply to a higher order than expected.

  12. Experimental Results on the First Short Pulse Laser Driven Neutron Source Powerful Enough For Applications In Radiography

    NASA Astrophysics Data System (ADS)

    Guler, Nevzat

    2012-10-01

    Short pulse laser driven neutron source can be a compact and relatively cheap way to produce neutrons with energies in excess of 10 MeV. It is based on short pulse laser driven ions interacting with a converter material to produce neutrons via separation or breakup mechanisms. Previous research on the short pulse laser driven ion acceleration has mainly concentrated on surface acceleration mechanisms, which typically yield isotropic emission of neutrons from the converter. Recent experiments performed with a high contrast laser at TRIDENT facility at LANL demonstrated laser driven ion acceleration mechanism based on the concept of relativistic transparency. This produced an intense beam of high energy (up to 80 MeV) deuterons directed into a Be converter to produce a forward peaked neutron flux with a record yield, on the order of 4.4x10^9 n/sr. The produced neutron beam had a pulse duration less than a nanosecond and an energy range between 2-80 MeV, peaking around 12 MeV. The neutrons in the energy range of 2.5 to 15 MeV were selected by the gated neutron imager to radiograph tungsten blocks of different thicknesses. We will present the results from the two acceleration mechanisms and the first short pulse laser generated neutron radiograph.

  13. Characterisation of electron beams from laser-driven particle accelerators

    SciTech Connect

    Brunetti, E.; Manahan, G. G.; Shanks, R. P.; Islam, M. R.; Ersfeld, B.; Anania, M. P.; Cipiccia, S.; Issac, R. C.; Vieux, G.; Welsh, G. H.; Wiggins, S. M.; Jaroszynski, D. A.

    2012-12-21

    The development, understanding and application of laser-driven particle accelerators require accurate measurements of the beam properties, in particular emittance, energy spread and bunch length. Here we report measurements and simulations showing that laser wakefield accelerators can produce beams of quality comparable to conventional linear accelerators.

  14. Neutron emission from fission fragments during acceleration p

    SciTech Connect

    Hinde, D.J.; Charity, R.J.; Foote, G.S.; Leigh, J.R.; Newton, J.O.; Ogaza, S.; Chatterjee, A.

    1984-03-19

    Fission-neutron angular correlations following fusion of /sup 19/F and /sup 232/Th have been measured. Conventional analysis, based on the approximation that post-fission neutrons originate only from fully accelerated fission fragments, gives unexpectedly large numbers of ''prefission'' neutrons. Comparison with the considerably less fissile system /sup 200/Pb gives the first convincing evidence that this approach is inadequate. Consideration of neutron emission from the accelerating fragments gives results consistent with expectations.

  15. Investigation of Lead Target Nuclei Used on Accelerator-Driven Systems for Tritium Production

    NASA Astrophysics Data System (ADS)

    Tel, E.; Aydin, A.

    2012-02-01

    High-current proton accelerators are being researched at Los Alamos National Laboratory and other laboratories for accelerator production of tritium, transmuting long-lived radioactive waste into shorter-lived products, converting excess plutonium, and producing energy. These technologies make use of spallation neutrons produced in ( p,xn) and ( n,xn) nuclear reactions on high-Z targets. Through ( p,xn) and ( n,xn) nuclear reactions, neutrons are produced and are moderated by heavy water. These moderated neutrons are subsequently captured on 3He to produce tritium via the ( n,p) reaction. Tritium self-sufficiency must be maintained for a commercial fusion power plant. Rubbia succeeded in a proposal of a full scale demonstration plant of the Energy Amplifier. This plant is to be known the accelerator-driven system (ADS). The ADS can be used for production of neutrons in spallation neutron source and they can act as an intense neutron source in accelerator-driven subcritical reactors, capable of incinerating nuclear waste and of producing energy. Thorium and Uranium are nuclear fuels and Lead, Bismuth, Tungsten are the target nuclei in these reactor systems. The spallation targets can be Pb, Bi, W, etc. isotopes and these target material can be liquid or solid. Naturally Lead includes the 204Pb (%1.42), 206Pb (%24.1), 207Pb (%22.1) and 208Pb (%52.3) isotopes. The design of ADS systems and also a fusion-fission hybrid reactor systems require the knowledge of a wide range of better data. In this study, by using Hartree-Fock method with an effective nucleon-nucleon Skyrme interactions rms nuclear charge radii, rms nuclear mass radii, rms nuclear proton, neutron radii and neutron skin thickness were calculated for the 204, 206, 208Pb isotopes . The calculated results have been compared with those of the compiled experimental and theoretical values of other studies.

  16. Generation of nanosecond neutron pulses in vacuum accelerating tubes

    NASA Astrophysics Data System (ADS)

    Didenko, A. N.; Shikanov, A. E.; Rashchikov, V. I.; Ryzhkov, V. I.; Shatokhin, V. L.

    2014-06-01

    The generation of neutron pulses with a duration of 1-100 ns using small vacuum accelerating tubes is considered. Two physical models of acceleration of short deuteron bunches in pulse neutron generators are described. The dependences of an instantaneous neutron flux in accelerating tubes on the parameters of pulse neutron generators are obtained using computer simulation. The results of experimental investigation of short-pulse neutron generators based on the accelerating tube with a vacuum-arc deuteron source, connected in the circuit with a discharge peaker, and an accelerating tube with a laser deuteron source, connected according to the Arkad'ev-Marx circuit, are given. In the experiments, the neutron yield per pulse reached 107 for a pulse duration of 10-100 ns. The resultant experimental data are in satisfactory agreement with the results of computer simulation.

  17. Production and Applications of Neutrons Using Particle Accelerators

    NASA Astrophysics Data System (ADS)

    Chichester, David L.

    2012-06-01

    Advances in neutron science have gone hand in hand with the development of particle accelerators from the beginning of both fields. Early accelerator systems were developed simply to produce neutrons, allowing scientists to study their properties and interactions with matter, but people quickly realized that more tangible uses existed for them. Today, these systems are in use in such diverse applications as mineral assaying, oil well logging, radiography, and explosive detection to name a few. This chapter presents a technical introduction to the different ways particle accelerators are used to produce neutrons, an historical overview of the development of neutron-producing particle accelerators, a description of current industrial accelerator systems, narratives of the industrial fields where neutron-producing particle accelerators are used today, and comments on future trends.

  18. Accelerator-driven transmutation of spent fuel elements

    DOEpatents

    Venneri, Francesco; Williamson, Mark A.; Li, Ning

    2002-01-01

    An apparatus and method is described for transmuting higher actinides, plutonium and selected fission products in a liquid-fuel subcritical assembly. Uranium may also be enriched, thereby providing new fuel for use in conventional nuclear power plants. An accelerator provides the additional neutrons required to perform the processes. The size of the accelerator needed to complete fuel cycle closure depends on the neutron efficiency of the supported reactors and on the neutron spectrum of the actinide transmutation apparatus. Treatment of spent fuel from light water reactors (LWRs) using uranium-based fuel will require the largest accelerator power, whereas neutron-efficient high temperature gas reactors (HTGRs) or CANDU reactors will require the smallest accelerator power, especially if thorium is introduced into the newly generated fuel according to the teachings of the present invention. Fast spectrum actinide transmutation apparatus (based on liquid-metal fuel) will take full advantage of the accelerator-produced source neutrons and provide maximum utilization of the actinide-generated fission neutrons. However, near-thermal transmutation apparatus will require lower standing

  19. Study of a multi-beam accelerator driven thorium reactor

    SciTech Connect

    Ludewig, H.; Aronson, A.

    2011-03-01

    be supplying source neutrons. The proton beam will be assumed to have an energy of 1 GeV, and the target material will be natural lead, which will also be the coolant for the reactor assembly. Three proton beam arrangements will be considered, first a single beam (the traditional arrangement) with an entry at the assembly center, two more options will consist of three and six entry locations. The reactor fuel assembly parameters will be based on those of the S-PRISM fast reactor proposed by GE, and the fuel composition and type will be based on that proposed by Aker Solutions for use in their accelerator driven thorium reactor. The following table summarizes the parameters to be used in this study. The isotopic composition of the fertile material is 100% Th-232, and the plutonium isotopic distribution corresponds to that characteristic of the discharge from a typical LWR, following five years of decay. Thus, the isotopic distribution for the plutonium is; Pu-238 2.5%, Pu-239 53.3%, Pu-240 25.1%, Pu-241 11.8%, and Pu-242 7.3%.

  20. Requirements of a proton beam accelerator for an accelerator-driven reactor

    SciTech Connect

    Takahashi, H.; Zhao, Y.; Tsoupas, N.; An, Y.; Yamazaki, Y.

    1997-12-31

    When the authors first proposed an accelerator-driven reactor, the concept was opposed by physicists who had earlier used the accelerator for their physics experiments. This opposition arose because they had nuisance experiences in that the accelerator was not reliable, and very often disrupted their work as the accelerator shut down due to electric tripping. This paper discusses the requirements for the proton beam accelerator. It addresses how to solve the tripping problem and how to shape the proton beam.

  1. Laser driven acceleration in vacuum and gases

    SciTech Connect

    Sprangle, P.; Esarey, E.; Hafizi, B.; Hubbard, R.; Krall, J.; Ting, A.

    1997-03-01

    Several important issues pertaining to particle acceleration in vacuum and gases are discussed. The limitations of laser vacuum acceleration as they relate to electron slippage, laser diffraction, material damage, and electron aperture effects are presented. Limitations on the laser intensity and particle self-fields due to material breakdown are quantified. In addition, the reflection of the self-fields associated with the accelerated particles places a limit on the number of particles. Two configurations for the inverse Cherenkov accelerator (ICA) are considered, in which the electromagnetic driver is propagated in a waveguide that is (i) lined with a dielectric material or (ii) filled with a neutral gas. The acceleration gradient in the ICA is limited by tunneling and collisional ionization in the dielectric liner or gas. Ionization can lead to significant modification of the optical properties of the waveguide, altering the phase velocity and causing particle slippage, thus disrupting the acceleration process. Maximum accelerating gradients and pulse durations are presented for a 10 {mu}m and a 1 mm wavelength driver. We show that the use of an unguided Bessel (axicon) beam can enhance the energy gain compared to a higher order Gaussian beam. The enhancement factor is N{sup 1/2}, where N is the number of lobes in the Bessel beam. {copyright} {ital 1997 American Institute of Physics.}

  2. Laser driven electron acceleration in vacuum, gases and plasmas

    SciTech Connect

    Sprangle, P.; Esarey, E.; Krall, J.

    1996-04-19

    This paper discusses some of the important issues pertaining to laser acceleration in vacuum, neutral gases and plasmas. The limitations of laser vacuum acceleration as they relate to electron slippage, laser diffraction, material damage and electron aperture effects, are discussed. An inverse Cherenkov laser acceleration configuration is presented in which a laser beam is self guided in a partially ionized gas. Optical self guiding is the result of a balance between the nonlinear self focusing properties of neutral gases and the diffraction effects of ionization. The stability of self guided beams is analyzed and discussed. In addition, aspects of the laser wakefield accelerator are presented and laser driven accelerator experiments are briefly discussed.

  3. First experiments on neutron detection on the accelerator-based source for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Kuznetsov, A. S.; Malyshkin, G. N.; Makarov, A. N.; Sorokin, I. N.; Sulyaev, Yu. S.; Taskaev, S. Yu.

    2009-04-01

    A pilot accelerator-based source of epithermal neutrons, which is intended for wide application in clinics for boron neutron capture therapy, has been constructed at the Budker Institute of Nuclear Physics (Novosibirsk). A stationary proton beam has been obtained and near-threshold neutron generation regime has been realized. Results of the first experiments on neutron generation using the proposed source are described.

  4. Disposition of Nuclear Waste Using Subcritical Accelerator-Driven Systems

    SciTech Connect

    Doolen, G.D.; Venneri, F.; Li, N.; Williamson, M.A.; Houts, M.; Lawrence, G.

    1998-06-27

    ATW destroys virtually all the plutonium and higher actinides without reprocessing the spent fuel in a way that could lead to weapons material diversion. An ATW facility consists of three major elements: (1) a high-power proton linear accelerator; (2) a pyrochemical spent fuel treatment i waste cleanup system; (3) a liquid lead-bismuth cooled burner that produces and utilizes an intense source-driven neutron flux for transmutation in a heterogeneous (solid fuel) core. The concept is the result of many years of development at LANL as well as other major international research centers. Once demonstrated and developed, ATW could be an essential part of a global non-proliferation strategy for countries that could build up large quantities of plutonium from their commercial reactor waste. ATW technology, initially proposed in the US, has received wide and rapidly increasing attention abroad, especially in Europe and the Far East with major programs now being planned, organized and tided. Substantial convergence presently exists on the technology choices among the programs, opening the possibility of a strong and effective international collaboration on the phased development of the ATW technology.

  5. Bacterial cells enhance laser driven ion acceleration

    PubMed Central

    Dalui, Malay; Kundu, M.; Trivikram, T. Madhu; Rajeev, R.; Ray, Krishanu; Krishnamurthy, M.

    2014-01-01

    Intense laser produced plasmas generate hot electrons which in turn leads to ion acceleration. Ability to generate faster ions or hotter electrons using the same laser parameters is one of the main outstanding paradigms in the intense laser-plasma physics. Here, we present a simple, albeit, unconventional target that succeeds in generating 700 keV carbon ions where conventional targets for the same laser parameters generate at most 40 keV. A few layers of micron sized bacteria coating on a polished surface increases the laser energy coupling and generates a hotter plasma which is more effective for the ion acceleration compared to the conventional polished targets. Particle-in-cell simulations show that micro-particle coated target are much more effective in ion acceleration as seen in the experiment. We envisage that the accelerated, high-energy carbon ions can be used as a source for multiple applications. PMID:25102948

  6. Laser-driven electron acceleration in an inhomogeneous plasma channel

    SciTech Connect

    Zhang, Rong; Cheng, Li-Hong; Xue, Ju-Kui

    2015-12-15

    We study the laser-driven electron acceleration in a transversely inhomogeneous plasma channel. We find that, in inhomogeneous plasma channel, the developing of instability for electron acceleration and the electron energy gain can be controlled by adjusting the laser polarization angle and inhomogeneity of plasma channel. That is, we can short the accelerating length and enhance the energy gain in inhomogeneous plasma channel by adjusting the laser polarization angle and inhomogeneity of the plasma channel.

  7. Operation and reactivity measurements of an accelerator driven subcritical TRIGA reactor

    NASA Astrophysics Data System (ADS)

    O'Kelly, David Sean

    Experiments were performed at the Nuclear Engineering Teaching Laboratory (NETL) in 2005 and 2006 in which a 20 MeV linear electron accelerator operating as a photoneutron source was coupled to the TRIGA (Training, Research, Isotope production, General Atomics) Mark II research reactor at the University of Texas at Austin (UT) to simulate the operation and characteristics of a full-scale accelerator driven subcritical system (ADSS). The experimental program provided a relatively low-cost substitute for the higher power and complexity of internationally proposed systems utilizing proton accelerators and spallation neutron sources for an advanced ADSS that may be used for the burning of high-level radioactive waste. Various instrumentation methods that permitted ADSS neutron flux monitoring in high gamma radiation fields were successfully explored and the data was used to evaluate the Stochastic Pulsed Feynman method for reactivity monitoring.

  8. INSTRUMENTS AND METHODS OF INVESTIGATION: An accelerator-driven system for the destruction of nuclear waste

    NASA Astrophysics Data System (ADS)

    Revol, Jean-Pierre

    2003-07-01

    Progress in particle accelerator technology makes it possible to use a proton accelerator to produce energy and to destroy nuclear waste efficiently. The energy amplifier (EA) proposed by Carlo Rubbia and his group is a subcritical fast neutron system driven by a proton accelerator. It is particularly attractive for destroying, through fission, transuranic elements produced by presently operating nuclear reactors. The EA could also efficiently and at minimal cost transform long-lived fission fragments using the concept of adiabatic resonance crossing (ARC), recently tested at CERN with the TARC experiment. The ARC concept can be extended to several other domains of application (production of radioactive isotopes for medicine and industry, neutron research applications, etc.).

  9. Shielding analysis at the upper section of the accelerator-driven system.

    PubMed

    Sasa, Toshinobu; Yang, Jin An; Oigawa, Hiroyuki

    2005-01-01

    The proton beam duct of the accelerator-driven system (ADS) acts as a streaming path for spallation neutrons and photons and causes the activation of the magnets and other devices above the subcritical core. We have performed a streaming analysis at the upper section of the lead-bismuth target/cooled ADS (800 MWth). MCNPX was used to calculate the radiation dose from streamed neutrons and photons through the beam duct. For the secondary photon production calculation, cross sections for several actinides were substituted with plutonium because of the lack of gamma production cross section. From the results of this analysis, the neutron dose from the beam duct is seen to be about 20 orders higher than that of the bulk shield. The magnets and shield plug are heavily irradiated by streaming neutrons according to the DCHAIN-SP analysis. PMID:16604639

  10. Dynamics of the accelerator-driven system as a variable gain amplifier

    SciTech Connect

    Woosley, M.L. Jr.; Rydin, R.A.

    1995-12-31

    Historically, subcritical accelerator-driven systems have been called electronuclear devices. Interest in these devices has been revived for numerous nuclear applications, such as boron neutron capture therapy, accelerator transmutation of waste (ATW), and accelerator-based conversion (ABC). The latter systems are being investigated at Los Alamos National Laboratory for energy production and radioactive waste transmutation. The ATW and ABC in particular are accelerator-(source)-driven subcritical fluid-fueled systems. System dynamics are affected by movement of delayed neutron precursors and poisons into and out of the active multiplying region, giving both a reactivity effect and reduced {Beta} (called {Beta}{sub eff}). A salient dynamic characteristic of the system is that the neutron population (power) is very sensitive to the level of subcritical reactivity, which can depend on poisoning, depletion, and thermal feedback over short operational time scales. Ruby has pointed out that the dynamic behavior of systems containing sources is not fully appreciated. It is our purpose here to illustrate some of the more interesting dynamic characteristics of systems like ATW or ABC.

  11. Experimental subcritical facility driven by D-D/D-T neutron generator at BARC, India

    NASA Astrophysics Data System (ADS)

    Sinha, Amar; Roy, Tushar; Kashyap, Yogesh; Ray, Nirmal; Shukla, Mayank; Patel, Tarun; Bajpai, Shefali; Sarkar, P. S.; Bishnoi, Saroj

    2015-05-01

    The paper presents design of an experimental subcritical assembly driven by D-D/D-T neutron and preliminary experimental measurements. The system has been developed for investigating the static and dynamic neutronic properties of accelerator driven sub-critical systems. This system is modular in design and it is first in the series of subcritical assemblies being designed. The subcritical core consists of natural uranium fuel with high density polyethylene as moderator and beryllium oxide as reflector. The fuel is embedded in high density polyethylene moderator matrix. Estimated keff of the system is ∼0.89. One of the unique features of subcritical core is the use of Beryllium oxide (BeO) as reflector and HDPE as moderator making the assembly a compact modular system. The subcritical core is coupled to Purnima Neutron Generator which works in D-D and D-T mode with both DC and pulsed operation. It has facility for online source strength monitoring using neutron tagging and programmable source modulation. Preliminary experiments have been carried out for spatial flux measurement and reactivity estimation using pulsed neutron source (PNS) techniques with D-D neutrons. Further experiments are being planned to measure the reactivity and other kinetic parameters using noise methods. This facility would also be used for carrying out studies on effect of source importance and measurement of source multiplication factor ks and external neutron source efficiency φ∗ in great details. Experiments with D-T neutrons are also underway.

  12. Physics of Laser-driven plasma-based acceleration

    SciTech Connect

    Esarey, Eric; Schroeder, Carl B.

    2003-06-30

    The physics of plasma-based accelerators driven by short-pulse lasers is reviewed. This includes the laser wake-field accelerator, the plasma beat wave accelerator, the self-modulated laser wake-field accelerator, and plasma waves driven by multiple laser pulses. The properties of linear and nonlinear plasma waves are discussed, as well as electron acceleration in plasma waves. Methods for injecting and trapping plasma electrons in plasma waves are also discussed. Limits to the electron energy gain are summarized, including laser pulse direction, electron dephasing, laser pulse energy depletion, as well as beam loading limitations. The basic physics of laser pulse evolution in underdense plasmas is also reviewed. This includes the propagation, self-focusing, and guiding of laser pulses in uniform plasmas and plasmas with preformed density channels. Instabilities relevant to intense short-pulse laser-plasma interactions, such as Raman, self-modulation, and hose instabilities, are discussed. Recent experimental results are summarized.

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

    PubMed

    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. PMID:11003523

  14. Miniature accelerator-driven gamma source concept.

    SciTech Connect

    Garnett, R. W.; Chan, K. D.; Wangler, Thomas P.,; Wood R. L.; Carlsten, B. E.; Kirbie, H. C.

    2003-01-01

    Recent developments in W-band (-100 GHz) traveling wave tube technology at Los Alarnos may lead to a compact high-power W-band RE source. A conceptual design of a compact 8-MeV electron linac that codd be powered by this source is presented, including electromagnetic structure calculations, proposed rnicrojbbrication and manufacturing methods, supporting calculations to estimate accelerator performance, and gumma production rates based on preliminary target geometries and expected output beam current.

  15. Intense laser driven collision-less shock and ion acceleration in magnetized plasmas

    NASA Astrophysics Data System (ADS)

    Mima, K.; Jia, Q.; Cai, H. B.; Taguchi, T.; Nagatomo, H.; Sanz, J. R.; Honrubia, J.

    2016-05-01

    The generation of strong magnetic field with a laser driven coil has been demonstrated by many experiments. It is applicable to the magnetized fast ignition (MFI), the collision-less shock in the astrophysics and the ion shock acceleration. In this paper, the longitudinal magnetic field effect on the shock wave driven by the radiation pressure of an intense short pulse laser is investigated by theory and simulations. The transition of a laminar shock (electro static shock) to the turbulent shock (electromagnetic shock) occurs, when the external magnetic field is applied in near relativistic cut-off density plasmas. This transition leads to the enhancement of conversion of the laser energy into high energy ions. The enhancement of the conversion efficiency is important for the ion driven fast ignition and the laser driven neutron source. It is found that the total number of ions reflected by the shock increases by six time when the magnetic field is applied.

  16. GeV plasma accelerators driven in waveguides

    SciTech Connect

    Hooker, S.M.; Brunetti, E.; Esarey, E.; Gallacher, J.G.; Geddes,C.G.R.; Gonsalves, A.J.; Jaroszynski, D.A.; Kamperidis, C.; Kneip, S.; Krushelnick, K.; Leemans, W.P.; Mangles, S.P.D.; Murphy, C.D.; Nagler,B.; Najmudin, Z.; Nakamura, K.; Norreys, P.A.; Panasenko, D.; Rowlands-Rees, T.P.; Schroeder, C.B.; Toth, Cs.; Trines, R.

    2007-11-01

    During the last few years laser-driven plasma acceleratorshave been shown to generate quasi-monoenergetic electron beams withenergies up to several hundred MeV. Extending the output energy oflaser-driven plasma accelerators to the GeV range requires operation atplasma densities an order of magnitude lower, i.e. 1018 cm-3, andincreasing the distance over which acceleration is maintained from a fewmillimetres to a few tens of millimetres. One approach for achieving thisis to guide the driving laser pulse in the plasma channel formed in agas-filled capillary discharge waveguide. We present transverseinterferometric measurements of the evolution of the plasma channelformed and compare these measurements with models of the capillarydischarge. We describe in detail experiments performed at LawrenceBerkeley National Laboratory and at Rutherford Appleton Laboratory inwhich plasma accelerators were driven within this type of waveguide togenerate quasimonoenergetic electron beams with energies up to 1GeV.

  17. Bright Laser-Driven Neutron Source Based on the Relativistic Transparency of Solids

    NASA Astrophysics Data System (ADS)

    Roth, M.; Jung, D.; Falk, K.; Guler, N.; Deppert, O.; Devlin, M.; Favalli, A.; Fernandez, J.; Gautier, D.; Geissel, M.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Johnson, R. P.; Merrill, F.; Schaumann, G.; Schoenberg, K.; Schollmeier, M.; Shimada, T.; Taddeucci, T.; Tybo, J. L.; Wagner, F.; Wender, S. A.; Wilde, C. H.; Wurden, G. A.

    2013-01-01

    Neutrons are unique particles to probe samples in many fields of research ranging from biology to material sciences to engineering and security applications. Access to bright, pulsed sources is currently limited to large accelerator facilities and there has been a growing need for compact sources over the recent years. Short pulse laser driven neutron sources could be a compact and relatively cheap way to produce neutrons with energies in excess of 10 MeV. For more than a decade experiments have tried to obtain neutron numbers sufficient for applications. Our recent experiments demonstrated an ion acceleration mechanism based on the concept of relativistic transparency. Using this new mechanism, we produced an intense beam of high energy (up to 170 MeV) deuterons directed into a Be converter to produce a forward peaked neutron flux with a record yield, on the order of 1010n/sr. We present results comparing the two acceleration mechanisms and the first short pulse laser generated neutron radiograph.

  18. Bright laser-driven neutron source based on the relativistic transparency of solids.

    PubMed

    Roth, M; Jung, D; Falk, K; Guler, N; Deppert, O; Devlin, M; Favalli, A; Fernandez, J; Gautier, D; Geissel, M; Haight, R; Hamilton, C E; Hegelich, B M; Johnson, R P; Merrill, F; Schaumann, G; Schoenberg, K; Schollmeier, M; Shimada, T; Taddeucci, T; Tybo, J L; Wagner, F; Wender, S A; Wilde, C H; Wurden, G A

    2013-01-25

    Neutrons are unique particles to probe samples in many fields of research ranging from biology to material sciences to engineering and security applications. Access to bright, pulsed sources is currently limited to large accelerator facilities and there has been a growing need for compact sources over the recent years. Short pulse laser driven neutron sources could be a compact and relatively cheap way to produce neutrons with energies in excess of 10 MeV. For more than a decade experiments have tried to obtain neutron numbers sufficient for applications. Our recent experiments demonstrated an ion acceleration mechanism based on the concept of relativistic transparency. Using this new mechanism, we produced an intense beam of high energy (up to 170 MeV) deuterons directed into a Be converter to produce a forward peaked neutron flux with a record yield, on the order of 10(10)  n/sr. We present results comparing the two acceleration mechanisms and the first short pulse laser generated neutron radiograph. PMID:25166169

  19. Laser-driven Acceleration in Clustered Plasmas

    SciTech Connect

    Gao, X.; Wang, X.; Shim, B.; Downer, M. C.

    2009-01-22

    We propose a new approach to avoid dephasing limitation of laser wakefield acceleration by manipulating the group velocity of the driving pulse using clustered plasmas. We demonstrated the control of phase velocity in clustered plasmas by third harmonic generation and frequency domain interferometry experiments. The results agree with a numerical model. Based on this model, the group velocity of the driving pulse in clustered plasmas was calculated and the result shows the group velocity can approach the speed of light c in clustered plasmas.

  20. Compact Couplers for Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect

    Cowan, Benjamin; Lin, M.C.; Schwartz, Brian; Byer, Robert; McGuinness, Christopher; Colby, Eric; England, Robert; Noble, Robert; Spencer, James; /SLAC

    2012-07-02

    Photonic crystal waveguides are promising candidates for laser-driven accelerator structures because of their ability to confine a speed-of-light mode in an all-dielectric structure. Because of the difference between the group velocity of the waveguide mode and the particle bunch velocity, fields must be coupled into the accelerating waveguide at frequent intervals. Therefore efficient, compact couplers are critical to overall accelerator efficiency. We present designs and simulations of high-efficiency coupling to the accelerating mode in a three-dimensional photonic crystal waveguide from a waveguide adjoining it at 90{sup o}. We discuss details of the computation and the resulting transmission. We include some background on the accelerator structure and photonic crystal-based optical acceleration in general.

  1. Negative ion-driven associated particle neutron generator

    DOE PAGESBeta

    Antolak, A. J.; Leung, K. N.; Morse, D. H.; Donovan, D. C.; Chames, J. M.; Whaley, J. A.; Buchenauer, D. A.; Chen, A. X.; Hausladen, P. A.; Liang, F.

    2015-10-09

    We describe an associated particle neutron generator that employs a negative ion source to produce high neutron flux from a small source size. Furthermore, negative ions produced in an rf-driven plasma source are extracted through a small aperture to form a beam which bombards a positively biased, high voltage target electrode. Electrons co-extracted with the negative ions are removed by a permanent magnet electron filter. The use of negative ions enables high neutron output (100% atomic ion beam), high quality imaging (small neutron source size), and reliable operation (no high voltage breakdowns). Finally, the neutron generator can operate in eithermore » pulsed or continuous-wave (cw) mode and has been demonstrated to produce 106 D-D n/s (equivalent to similar to 108 D-T n/s) from a 1 mm-diameter neutron source size to facilitate high fidelity associated particle imaging.« less

  2. Negative ion-driven associated particle neutron generator

    SciTech Connect

    Antolak, A. J.; Leung, K. N.; Morse, D. H.; Donovan, D. C.; Chames, J. M.; Whaley, J. A.; Buchenauer, D. A.; Chen, A. X.; Hausladen, P. A.; Liang, F.

    2015-10-09

    We describe an associated particle neutron generator that employs a negative ion source to produce high neutron flux from a small source size. Furthermore, negative ions produced in an rf-driven plasma source are extracted through a small aperture to form a beam which bombards a positively biased, high voltage target electrode. Electrons co-extracted with the negative ions are removed by a permanent magnet electron filter. The use of negative ions enables high neutron output (100% atomic ion beam), high quality imaging (small neutron source size), and reliable operation (no high voltage breakdowns). Finally, the neutron generator can operate in either pulsed or continuous-wave (cw) mode and has been demonstrated to produce 106 D-D n/s (equivalent to similar to 108 D-T n/s) from a 1 mm-diameter neutron source size to facilitate high fidelity associated particle imaging.

  3. Negative ion-driven associated particle neutron generator

    NASA Astrophysics Data System (ADS)

    Antolak, A. J.; Leung, K. N.; Morse, D. H.; Donovan, D. C.; Chames, J. M.; Whaley, J. A.; Buchenauer, D. A.; Chen, A. X.; Hausladen, P. A.; Liang, F.

    2016-01-01

    An associated particle neutron generator is described that employs a negative ion source to produce high neutron flux from a small source size. Negative ions produced in an rf-driven plasma source are extracted through a small aperture to form a beam which bombards a positively biased, high voltage target electrode. Electrons co-extracted with the negative ions are removed by a permanent magnet electron filter. The use of negative ions enables high neutron output (100% atomic ion beam), high quality imaging (small neutron source size), and reliable operation (no high voltage breakdowns). The neutron generator can operate in either pulsed or continuous-wave (cw) mode and has been demonstrated to produce 106 D-D n/s (equivalent to ~108 D-T n/s) from a 1 mm-diameter neutron source size to facilitate high fidelity associated particle imaging.

  4. Neutron-driven gamma-ray laser

    DOEpatents

    Bowman, Charles D.

    1990-01-01

    A lasing cylinder emits laser radiation at a gamma-ray wavelength of 0.87 .ANG. when subjected to an intense neutron flux of about 400 eV neutrons. A 250 .ANG. thick layer of Be is provided between two layers of 100 .ANG. thick layer of .sup.57 Co and these layers are supported on a foil substrate. The coated foil is coiled to form the lasing cylinder. Under the neutron flux .sup.57 Co becomes .sup.58 Co by neutron absorption. The .sup.58 Co then decays to .sup.57 Fe by 1.6 MeV proton emission. .sup.57 Fe then transitions by mesne decay to a population inversion for lasing action at 14.4 keV. Recoil from the proton emission separates the .sup.57 Fe from the .sup.57 Co and into the Be, where Mossbauer emission occurs at a gamma-ray wavelength.

  5. Accelerator-based neutron source for the neutron-capture and fast neutron therapy at hospital

    NASA Astrophysics Data System (ADS)

    Bayanov, B. F.; Belov, V. P.; Bender, E. D.; Bokhovko, M. V.; Dimov, G. I.; Kononov, V. N.; Kononov, O. E.; Kuksanov, N. K.; Palchikov, V. E.; Pivovarov, V. A.; Salimov, R. A.; Silvestrov, G. I.; Skrinsky, A. N.; Soloviov, N. A.; Taskaev, S. Yu.

    The proton accelerator complex for neutron production in lithium target discussed, which can operate in two modes. The first provides a neutron beam kinematically collimated with good forward direction in 25° and average energy of 30 keV, directly applicable for neutron-capture therapy with high efficiency of proton beam use. The proton energy in this mode is 1.883-1.890 MeV that is near the threshold of the 7Li( p, n) 7Be reaction. In the second mode, at proton energy of 2.5 MeV, the complex-produced neutron beam with maximum energy board of 790 keV which can be used directly for fast neutron therapy and for neutron-capture therapy after moderation. The project of such a neutron source is based on the 2.5 MeV original electrostatic accelerator tandem with vacuum insulation developed at BINP which is supplied with a high-voltage rectifier. The rectifier is produced in BINP as a part of ELV-type industrial accelerator. Design features of the tandem determining its high reliability in operation with a high-current (up to 40 mA) H - ion beam are discussed. They are: the absence of ceramic accelerator columns around the beam passage region, good conditions for pumping out of charge-exchange gaseous target region, strong focusing optics and high acceleration rate minimizing the space charge effects. The possibility of stabilization of protons energy with an accuracy level of 0.1% necessary for operation in the near threshold region is considered. The design description of H - continuous ion source with a current of 40 mA is also performed. To operate with a 100 kW proton beam it is proposed to use liquid-lithium targets. A thin lithium layer on the surface of a tungsten disk cooled intensively by a liquid metal heat carrier is proposed for use in case of the vertical beam, and a flat liquid lithium jet flowing through the narrow nozzle - for the horizontal beam.

  6. Application of Burnable Absorbers in an Accelerator-Driven System

    SciTech Connect

    Wallenius, Jan; Tucek, Kamil; Carlsson, Johan; Gudowski, Waclaw

    2001-01-15

    The application of burnable absorbers (BAs) to minimize power peaking, reactivity loss, and capture-to-fission probabilities in an accelerator-driven waste transmutation system has been investigated. Boron-10-enriched B{sub 4}C absorber rods were introduced into a lead-bismuth-cooled core fueled with transuranic (TRU) discharges from light water reactors to achieve the smallest possible power peakings at beginning-of-life (BOL) subcriticality level of 0.97. Detailed Monte Carlo simulations show that a radial power peaking equal to 1.2 at BOL is attainable using a four-zone differentiation in BA content. Using a newly written Monte Carlo burnup code, reactivity losses were calculated to be 640 pcm per percent TRU burnup for unrecycled TRU discharges. Comparing to corresponding values in BA-free cores, BA introduction diminishes reactivity losses in TRU-fueled subcritical cores by {approx}20%. Radial power peaking after 300 days of operation at 1200-MW thermal power was <1.75 at a subcriticality level of {approx}0.92, which appears to be acceptable, with respect to limitations in cladding and fuel temperatures. In addition, the use of BAs yields significantly higher fission-to-capture probabilities in even-neutron-number nuclides. Fission-to-absorption probability ratio for {sup 241}Am equal to 0.33 was achieved in the configuration studied. Hence, production of the strong alpha-emitter {sup 242}Cm is reduced, leading to smaller fuel-swelling rates and pin pressurization. Disadvantages following BA introduction, such as increase of void worth and decrease of Doppler feedback in conjunction with small values of {beta}{sub eff}, need to be addressed by detailed studies of subcritical core dynamics.

  7. Accelerator-Driven Subcritical Reactors in Japanese Universities: Experimental Study Using the Kyoto University Critical Assembly

    SciTech Connect

    Shiroya, S.; Unesaki, H.; Misawa, T.

    2001-06-17

    A series of basic experiments for an accelerator-driven sub-critical reactor (ADSR) was officially launched in financial year 2000 at the Kyoto University Critical Assembly (KUCA) as a joint-use program among Japanese universities. These experiments are closely related to the future plan of the Kyoto University Research Reactor Institute. A final goal of this plan is to establish a next-generation neutron source as a substitute for the 5-MW Kyoto University Reactor and based on the ADSR concept to promote joint research among Japanese universities. An attractive point of the ADSR system is that either pulsed or steady neutrons can be provided depending on the accelerator's operation mode.

  8. Neutron Scattering Simulations at the University of Kentucky Accelerator Laboratory

    NASA Astrophysics Data System (ADS)

    Nguyen, Thienan; Jackson, Daniel; Hicks, S. F.; Rice, Ben; Vanhoy, J. R.

    2015-10-01

    The Monte-Carlo N-Particle Transport code (MCNP) has many applications ranging from radiography to reactor design. It has particle interaction capabilities, making it useful for simulating neutron collisions on surfaces of varying compositions. The neutron flux within the accelerator complex at the University of Kentucky was simulated using MCNP. With it, the complex's capabilities to contain and thermalize 7 MeV neutrons produced via 2H(d,n)3He source reaction to an acceptable level inside the neutron hall and adjoining rooms were analyzed. This will aid in confirming the safety of researchers who are working in the adjacent control room. Additionally, the neutron transport simulation was used to analyze the impact of the collimator copper shielding on various detectors located around the neutron scattering hall. The purpose of this was to attempt to explain any background neutrons that are observed at these detectors. The simulation shows that the complex performs very well with regards to neutron containment and thermalization. Also, the tracking information for the paths taken by the neutrons show that most of the neutrons' lives are spent inside the neutron hall. Finally, the neutron counts were analyzed at the positions of the neutron monitor detectors located at 90 and 45 degrees relative to the incident beam direction. This project was supported in part by the DOE NEUP Grant NU-12-KY-UK-0201-05 and the Donald A. Cowan Physics Institute at the University of Dallas.

  9. Disposition of Nuclear Waste Using Subcritical Accelerator-Driven Systems: Technology Choices and Implementation Scenarios

    SciTech Connect

    Venneri, Francesco; Williamson, Mark A.; Li Ning; Houts, Michael G.; Morley, Richard A.; Beller, Denis E.; Sailor, William; Lawrence, George

    2000-10-15

    Los Alamos National Laboratory has led the development of accelerator-driven transmutation of waste (ATW) to provide an alternative technological solution to the disposition of nuclear waste. While ATW will not eliminate the need for a high-level waste repository, it offers a new technology option for altering the nature of nuclear waste and enhancing the capability of a repository. The basic concept of ATW focuses on reducing the time horizon for the radiological risk from hundreds of thousands of years to a few hundred years and on reducing the thermal loading. As such, ATW will greatly reduce the amount of transuranic elements that will be disposed of in a high-level waste repository. The goal of the ATW nuclear subsystem is to produce three orders of magnitude reduction in the long-term radiotoxicity of the waste sent to a repository, including losses through processing. If the goal is met, the radiotoxicity of ATW-treated waste after 300 yr would be less than that of untreated waste after 100 000 yr.These objectives can be achieved through the use of high neutron fluxes produced in accelerator-driven subcritical systems. While critical fission reactors can produce high neutron fluxes to destroy actinides and select fission products, the effectiveness of the destruction is limited by the criticality requirement. Furthermore, a substantial amount of excess reactivity would have to be supplied initially and compensated for by control poisons. To overcome these intrinsic limitations, we searched for solutions in subcritical systems freed from the criticality requirement by taking advantage of the recent breakthroughs in accelerator technology and the release of liquid lead/bismuth nuclear coolant technology from Russia. The effort led to the selection of an accelerator-driven subcritical system that results in the destruction of the actinides and fission products of concern as well as permitting easy operational control through the external control of the neutron

  10. Leakage neutron radiation in a medical electron accelerator

    NASA Astrophysics Data System (ADS)

    Paredes, Lydia; Balcazar, Miguel; Genis, Roberto; Ortiz, Raúl

    2001-10-01

    A simple method was used for the calculation of neutron yield produced by main components of medical electron accelerator head, using a simplified geometric model with spherical-shell for the head shielding made of different materials. The leakage neutron radiation on the patient plane and outside the patient plane at one meter from the x-ray target for a Varian accelerator model Clinac 2100C was evaluated experimentally, using Panasonic UD-802 and UD-809 thermoluminescent dosimeters and CR-39 nuclear track dosimeters. The measured values of leakage neutron radiation were lower than the limits specified in the NCRP-102 and IEC 60601-2-1-Ed.2.0 reports.

  11. Towards GeV laser-driven ion acceleration

    NASA Astrophysics Data System (ADS)

    Hegelich, B. M.; Yin, L.; Albright, B. J.; Flippo, K. A.; Gautier, D. C.; Johnson, R. P.; Letzring, S.; Shah, R. C.; Shimada, T.; Fernandez, J. C.; Henig, A.; Kiefer, D.; Liechtenstein, V.; Schreiber, J.; Habs, D.; Meyer-Ter-Vehn, J.; Rykovanov, S.; Wu, H. C.

    2008-11-01

    Applications like ion-driven fast ignition (IFI) with heavy ions or laser-based hadron therapy require efficient laser-driven ion acceleration to ˜ 0.1 -- 1 GeV. The Break-Out Afterburner (BOA) [1] regime and the Phase-Stable Acceleration (PSA) [2] regime, also reported as Radiation Pressure Acceleration (RPA) [3], promise quasi-monoenergetic beams at such energies, with ˜ 10% efficiency,. This talk summarizes our joint exploratory research program in this new and exciting area, emphasizing the realization of these mechanisms with today's lasers. The laser requirements are discussed, especially pulse contrast. The first experimental results are reported. [1] L. Yin et al., Laser & Part. Beams 24, 1-8 (2006) [2] X. Zhang et al., Phys. Plasmas 14, 123108 (2007) [3] A. P. L. Robinson et al., New J. Phys. 10, 013021 (2008)

  12. High Intensity Accelerator and Neutron Source in China

    SciTech Connect

    Guan Xialing; Wei, J.; Loong Chun

    2011-06-28

    High intensity Accelerator is being studied all over world for numerous applications, which includes the waste transmutation, spallation neutron source and material irradiation facilities. The R/D activities of the technology of High intensity accelerator are also developed in China for some year, and have some good facilities around China. This paper will reports the status of some high intensity accelerators and neutron source in China, which including ADS/RFQ; CARR; CSNS; PKUNIFTY and CPHS. This paper will emphatically report the Compact Pulsed Hadron Source (CPHS) led by the Department of Engineering Physics of Tsinghua University in Beijing, China.

  13. Beam-driven acceleration in ultra-dense plasma media

    SciTech Connect

    Shin, Young-Min

    2014-09-15

    Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 10{sup 25 }m{sup −3} and 1.6 × 10{sup 28 }m{sup −3} plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers ∼20% higher acceleration gradient by enlarging the channel radius (r) from 0.2 λ{sub p} to 0.6 λ{sub p} in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g., nanotubes) of high electron plasma density.

  14. Beam-driven acceleration in ultra-dense plasma media

    DOE PAGESBeta

    Shin, Young-Min

    2014-09-15

    Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 1025 m-3 and 1.6 x 1028 m-3 plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers 20 % higher acceleration gradient by enlarging the channel radius (r)more » from 0.2 Ap to 0.6 .Ap in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g. nanotubes) of high electron plasma density.« less

  15. Beam-driven acceleration in ultra-dense plasma media

    SciTech Connect

    Shin, Young-Min

    2014-09-15

    Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 1025 m-3 and 1.6 x 1028 m-3 plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers 20 % higher acceleration gradient by enlarging the channel radius (r) from 0.2 Ap to 0.6 .Ap in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g. nanotubes) of high electron plasma density.

  16. Fusion-neutron-yield, activation measurements at the Z accelerator: design, analysis, and sensitivity.

    PubMed

    Hahn, K D; Cooper, G W; Ruiz, C L; Fehl, D L; Chandler, G A; Knapp, P F; Leeper, R J; Nelson, A J; Smelser, R M; Torres, J A

    2014-04-01

    We present a general methodology to determine the diagnostic sensitivity that is directly applicable to neutron-activation diagnostics fielded on a wide variety of neutron-producing experiments, which include inertial-confinement fusion (ICF), dense plasma focus, and ion beam-driven concepts. This approach includes a combination of several effects: (1) non-isotropic neutron emission; (2) the 1/r(2) decrease in neutron fluence in the activation material; (3) the spatially distributed neutron scattering, attenuation, and energy losses due to the fielding environment and activation material itself; and (4) temporally varying neutron emission. As an example, we describe the copper-activation diagnostic used to measure secondary deuterium-tritium fusion-neutron yields on ICF experiments conducted on the pulsed-power Z Accelerator at Sandia National Laboratories. Using this methodology along with results from absolute calibrations and Monte Carlo simulations, we find that for the diagnostic configuration on Z, the diagnostic sensitivity is 0.037% ± 17% counts/neutron per cm(2) and is ∼ 40% less sensitive than it would be in an ideal geometry due to neutron attenuation, scattering, and energy-loss effects. PMID:24784607

  17. Fusion-neutron-yield, activation measurements at the Z accelerator: Design, analysis, and sensitivity

    SciTech Connect

    Hahn, K. D. Ruiz, C. L.; Fehl, D. L.; Chandler, G. A.; Knapp, P. F.; Smelser, R. M.; Torres, J. A.; Cooper, G. W.; Nelson, A. J.; Leeper, R. J.

    2014-04-15

    We present a general methodology to determine the diagnostic sensitivity that is directly applicable to neutron-activation diagnostics fielded on a wide variety of neutron-producing experiments, which include inertial-confinement fusion (ICF), dense plasma focus, and ion beam-driven concepts. This approach includes a combination of several effects: (1) non-isotropic neutron emission; (2) the 1/r{sup 2} decrease in neutron fluence in the activation material; (3) the spatially distributed neutron scattering, attenuation, and energy losses due to the fielding environment and activation material itself; and (4) temporally varying neutron emission. As an example, we describe the copper-activation diagnostic used to measure secondary deuterium-tritium fusion-neutron yields on ICF experiments conducted on the pulsed-power Z Accelerator at Sandia National Laboratories. Using this methodology along with results from absolute calibrations and Monte Carlo simulations, we find that for the diagnostic configuration on Z, the diagnostic sensitivity is 0.037% ± 17% counts/neutron per cm{sup 2} and is ∼ 40% less sensitive than it would be in an ideal geometry due to neutron attenuation, scattering, and energy-loss effects.

  18. Fusion-neutron-yield, activation measurements at the Z accelerator: Design, analysis, and sensitivity

    NASA Astrophysics Data System (ADS)

    Hahn, K. D.; Cooper, G. W.; Ruiz, C. L.; Fehl, D. L.; Chandler, G. A.; Knapp, P. F.; Leeper, R. J.; Nelson, A. J.; Smelser, R. M.; Torres, J. A.

    2014-04-01

    We present a general methodology to determine the diagnostic sensitivity that is directly applicable to neutron-activation diagnostics fielded on a wide variety of neutron-producing experiments, which include inertial-confinement fusion (ICF), dense plasma focus, and ion beam-driven concepts. This approach includes a combination of several effects: (1) non-isotropic neutron emission; (2) the 1/r2 decrease in neutron fluence in the activation material; (3) the spatially distributed neutron scattering, attenuation, and energy losses due to the fielding environment and activation material itself; and (4) temporally varying neutron emission. As an example, we describe the copper-activation diagnostic used to measure secondary deuterium-tritium fusion-neutron yields on ICF experiments conducted on the pulsed-power Z Accelerator at Sandia National Laboratories. Using this methodology along with results from absolute calibrations and Monte Carlo simulations, we find that for the diagnostic configuration on Z, the diagnostic sensitivity is 0.037% ± 17% counts/neutron per cm2 and is ˜ 40% less sensitive than it would be in an ideal geometry due to neutron attenuation, scattering, and energy-loss effects.

  19. Magnetically driven crustquakes in neutron stars

    NASA Astrophysics Data System (ADS)

    Lander, S. K.; Andersson, N.; Antonopoulou, D.; Watts, A. L.

    2015-05-01

    Crustquake events may be connected with both rapid spin-up `glitches' within the regular slowdown of neutron stars, and high-energy magnetar flares. We argue that magnetic-field decay builds up stresses in a neutron star's crust, as the elastic shear force resists the Lorentz force's desire to rearrange the global magnetic-field equilibrium. We derive a criterion for crust-breaking induced by a changing magnetic-field configuration, and use this to investigate strain patterns in a neutron star's crust for a variety of different magnetic-field models. Universally, we find that the crust is most liable to break if the magnetic field has a strong toroidal component, in which case the epicentre of the crustquake is around the equator. We calculate the energy released in a crustquake as a function of the fracture depth, finding that it is independent of field strength. Crust-breaking is, however, associated with a characteristic local field strength of 2.4 × 1014 G for a breaking strain of 0.001, or 2.4 × 1015 G at a breaking strain of 0.1. We find that even the most luminous magnetar giant flare could have been powered by crustal energy release alone.

  20. Accretion Acceleration of Neutron Stars and Effects of Gravitational Radiation

    NASA Astrophysics Data System (ADS)

    Fu, Yan-yan; Zhang, Yue-zhu; Wei, Yi-huan; Zhang, Cheng-min; Yu, Shao-hua; Pan, Yuan-yue; Guo, Yuan-qi; Wang, De-hua

    2016-01-01

    In this paper we studied the neutron star's spin acceleration in the accretion process of the neutron star binary system, and the relation how the spin period changes with the accreted mass. We analyzed further the evolutions of both magnetic field and spin period of a neutron star, and compared the modeled results with the observational data of pulsars, to show that they are consistent with each other. Based on above studies, we investigated the effect of gravitational radiation on the spin-up process of a neutron star, and derived the change rate of the neutron star's spin period in the accretion process. We also estimated the critical angular velocity Ωcr, at which the accretion torque is balanced by that of gravitational radiation, and discussed the influence of gravitational radiation on the neutron star's spin evolution.

  1. The study of neutron burst shape of a neutron tube driven by dispenser cathode

    NASA Astrophysics Data System (ADS)

    Grishnyaev, Evgeny; Polosatkin, Sergey

    2016-08-01

    A slim-shaped portable DD-neutron generator is developed at Budker institute of Nuclear Physics. The generator is a combination of Cockcroft-Walton voltage multiplier and a sealed gas-filled neutron tube driven by dispenser cathode. Neutron burst shape in pulsed mode of neutron tube operation is measured with stroboscopic time spectrometry, implemented on scintillation detector, and modeled with Comsol Script 1.3 and Comsol Multiphysics 3.5. Modeling appears to be in good agreement with experimental results. Measured pulse rise and fall times are 110 ns and 100 ns respectively.

  2. Acceleration and deceleration of neutrons: From the phase modulation of a neutron wave to a neutron turbine with refracting prisms

    SciTech Connect

    Frank, A. I.

    2013-05-15

    The possibility of the acceleration and deceleration of neutrons undergoing diffraction at a moving grating is discussed. It is shown that, in contrast to phase {pi} gratings used at the present time, which form a discrete spectrum featuring a large number of lines, a grating that has a special profile may shift, under certain conditions, the entire spectrum of diffracted neutrons. A blazing grating of this type may be used in efficiently accelerating and decelerating neutrons. As the scale of the structure becomes larger, a description based on the idea of neutron-wave refraction at its elements becomes valid, a system of moving prims forming a 'neutron turbine,' which is also able to accelerate or decelerate neutrons, being a classical limit of this enlargement.

  3. Physics of laser-driven plasma-based electron accelerators

    SciTech Connect

    Esarey, E.; Schroeder, C. B.; Leemans, W. P.

    2009-07-15

    Laser-driven plasma-based accelerators, which are capable of supporting fields in excess of 100 GV/m, are reviewed. This includes the laser wakefield accelerator, the plasma beat wave accelerator, the self-modulated laser wakefield accelerator, plasma waves driven by multiple laser pulses, and highly nonlinear regimes. The properties of linear and nonlinear plasma waves are discussed, as well as electron acceleration in plasma waves. Methods for injecting and trapping plasma electrons in plasma waves are also discussed. Limits to the electron energy gain are summarized, including laser pulse diffraction, electron dephasing, laser pulse energy depletion, and beam loading limitations. The basic physics of laser pulse evolution in underdense plasmas is also reviewed. This includes the propagation, self-focusing, and guiding of laser pulses in uniform plasmas and with preformed density channels. Instabilities relevant to intense short-pulse laser-plasma interactions, such as Raman, self-modulation, and hose instabilities, are discussed. Experiments demonstrating key physics, such as the production of high-quality electron bunches at energies of 0.1-1 GeV, are summarized.

  4. Nonlinear Laser Driven Donut Wakefields for Positron and Electron Acceleration

    NASA Astrophysics Data System (ADS)

    Vieira, J.; Mendonça, J. T.

    2014-05-01

    We show analytically and through three-dimensional particle-in-cell simulations that nonlinear wakefields driven by Laguerre-Gaussian laser pulses can lead to hollow electron self-injection and positron acceleration. We find that higher order lasers can drive donut shaped blowout wakefields with strong positron accelerating gradients comparable to those of a spherical bubble. Corresponding positron focusing forces can be more than an order of magnitude stronger than electron focusing forces in a spherical bubble. Required laser intensities and energies to reach the nonlinear donut shaped blowout are within state-of-the-art experimental conditions.

  5. The laser driven particle accelerator project: Theory and experiment

    SciTech Connect

    Plettner, T.; Byer, R.L. Smith, T.I.; Siemann, R.H. Huang, Y.C.

    1999-07-01

    A proof of principle experiment for laser driven electron acceleration from crossed laser beams in a dielectric loaded vacuum is being carried out at Stanford University. We seek to measure a maximum energy gain of about 250 keV for a 30{endash}35 MeV electron beam in one accelerator cell. We use laser pulses of a few picoseconds of duration from a regenerative Ti:sapphire laser amplifier at a wavelength of 800 nm in a laser-electron interaction distance of {approximately}1 mm. {copyright} {ital 1999 American Institute of Physics.}

  6. Three-Dimensional Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect

    Cowan, B.; /SLAC

    2006-09-07

    We discuss simulated photonic crystal structure designs for laser-driven particle acceleration, focusing on three-dimensional planar structures based on the so-called ''woodpile'' lattice. We describe guiding of a speed-of-light accelerating mode by a defect in the photonic crystal lattice and discuss the properties of this mode, including particle beam dynamics and potential coupling methods for the structure. We also discuss possible materials and power sources for this structure and their effects on performance parameters, as well as possible manufacturing techniques and the required tolerances. In addition we describe the computational technique and possible improvements in numerical modeling that would aid development of photonic crystal structures.

  7. Nuclear data needs for accelerator-driven transmutation systems

    SciTech Connect

    Arthur, E.D.; Wilson, W.B.; Young, P.G.

    1994-07-01

    The possibilities of several new technologies based on use of intense, medium-energy proton accelerators are being investigated at Los Alamos National Laboratory. The potential new areas include destruction of long-lived components of nuclear waste, plutonium burning, energy production, and production of tritium. The design, assessment, and safety analysis of potential facilities involves the understanding of complex combinations of nuclear processes, which in turn places new requirements on nuclear data that transcend the traditional needs of the fission and fusion reactor communities. In this paper an assessment of the nuclear data needs for systems currently being considered in the Los Alamos Accelerator-Driven Transmutation Technologies program is given.

  8. Acceleration of SEPs in Flaring Loops and CME Driven shocks

    NASA Astrophysics Data System (ADS)

    Petrosian, Vahe; Chen, Qingrong

    2014-06-01

    We consider two stage acceleration of the Solar Energetic Particles (SEPs). The first occurring via the stochastic acceleration mechanism at the flare site in the corona, which produces the so-called impulsive SEPs, with anomalous abundances, as well as nonthermal particles responsible for the observed radiation. The second is re-acceleration the flare accelerated particles at the CME driven shock associated with larger, longer duration events with relatively normal abundances. Turbulence plays a major role in both stages. We will show how stochastic acceleration can explain some of the salient features of the impulsive SEP observations; such as extreme enrichment of 3He (and heavy ions), and the observed broad distributions and ranges of the 3He and 4He fluences. We will then show that the above hybrid mechanism of first stochastic acceleration of ions in the reconnecting coronal magnetic structures and then their re-acceleration in the CME shock can produce the varied shapes of the 3He and 4He spectra observed in all events ranging from weak impulsive to strong gradual events.

  9. A New Type of Plasma Wakefield Accelerator Driven By Magnetowaves

    SciTech Connect

    Chen, Pisin; Chang, Feng-Yin; Lin, Guey-Lin; Noble, Robert J.; Sydora, Richard; /Alberta U.

    2011-09-12

    We present a new concept for a plasma wakefield accelerator driven by magnetowaves (MPWA). This concept was originally proposed as a viable mechanism for the 'cosmic accelerator' that would accelerate cosmic particles to ultra-high energies in the astrophysical setting. Unlike the more familiar plasma wakefield accelerator (PWFA) and the laser wakefield accelerator (LWFA) where the drivers, the charged-particle beam and the laser, are independently existing entities, MPWA invokes the high-frequency and high-speed whistler mode as the driver, which is a medium wave that cannot exist outside of the plasma. Aside from the difference in drivers, the underlying mechanism that excites the plasma wakefield via the ponderomotive potential is common. Our computer simulations show that under appropriate conditions, the plasma wakefield maintains very high coherence and can sustain high-gradient acceleration over many plasma wavelengths. We suggest that in addition to its celestial application, the MPWA concept can also be of terrestrial utility. A proof-of-principle experiment on MPWA would benefit both terrestrial and celestial accelerator concepts.

  10. Laser-and Beam-Driven Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Joshi, Chandrashekhar

    2006-10-01

    Scientists have been trying to use the tremendous electric fields in relativistic plasma waves to accelerate charged particles, and are now making substantial progress. If they succeed, future high energy accelerators will use plasma waves rather than microwave cavities as accelerating structures.Some accelerators, such as those used for radiation therapy will fit on a tabletop. Research on using plasma waves to accelerate particles began in earnest following the suggestion by John Dawson and his colleagues [1-3] that a relativistically propagating plasma wave or a wake field could be excited by using a powerful but short laser -or electron -beam as a driver pulse.Since their original suggestion the research on plasma --based accelerators has spread worldwide A series of experiments by the UCLA/USC/SLAC collaboration ,using the 30 GeV beam of the Stanford Linear Accelerator Center (SLAC), has demonstrated high-gradient acceleration of electrons and positrons using the the wake left by the SLAC beam as it passes through a lithium plasma. Electrons have been accelerated by more than 30 GeV in less than one meter. This acceleration gradient is about a thousand times larger than in conventional microwave-driven accelerators. It is a first step toward a ``plasma afterburner,'' which would be placed at the end of a kilometers-long conventional accelerator and double its beam energy in a few tens of meters. In addition to the acceleration of particle beams, these experiments have demonstrated the rich physics bounty to be reaped from relativistic beam-plasma interactions. This includes the generation of intense and narrowly collimated x-ray beams, refraction of particles at a plasma interface, and the creation of intense beams of positrons. These results are leading the way to similar tabletop accelerators based on plasma wakes excited by lasers rather than electron beams. Applications for tabletop accelerators include gamma radiography, radiation therapy, and ultra

  11. Maximizing the Efficacy of Accelerator-Produced Neutrons for BNCT

    SciTech Connect

    Jay F. Kunze; J. Frank Harmon; Rajat Kudchadker; Chad L. Lee

    2000-06-04

    Production of neutrons for boron neutron capture therapy (BNCT) treatment of malignant brain tumors will best be served if the neutrons can be produced by accelerators rather than nuclear reactors. The neutron production reaction that has been most thoroughly examined using accelerators is {sup 7}Li(n, p){sup 7}Be, generally on a thick lithium target. The threshold for this reactor is 1.88 MeV, and the yield curve for neutron production rises quite rapidly up to 2.3 MeV, where the positive slope is reduced significantly. In considering the design of a neutron production device, it has been traditional to use proton energies in the 2.4- to 2.5-MeV range. Over the last several years, our group has been working with lower-energy protons, just above the threshold for neutron production. The advantage is that the neutrons produced would have much lower energy and hence need much less moderator. The principal disadvantage of operating at these near-threshold energies is that the yield from the target is substantially reduced from that at or near 2.5-MeV proton energy. Table I shows the results of calculations to find an optimum energy for 3-mA proton beam on target. In general, we have concluded that 1.96 to 1.98 MeV is probably optimum for a tumor 5 cm below the skull.

  12. Novel neutron sources at the Radiological Research Accelerator Facility.

    PubMed

    Xu, Yanping; Garty, Guy; Marino, Stephen A; Massey, Thomas N; Randers-Pehrson, Gerhard; Johnson, Gary W; Brenner, David J

    2012-03-16

    Since the 1960s, the Radiological Research Accelerator Facility (RARAF) has been providing researchers in biology, chemistry and physics with advanced irradiation techniques, using charged particles, photons and neutrons.We are currently developing a unique facility at RARAF, to simulate neutron spectra from an improvised nuclear device (IND), based on calculations of the neutron spectrum at 1.5 km from the epicenter of the Hiroshima atom bomb. This is significantly different from a standard fission spectrum, because the spectrum changes as the neutrons are transported through air, and is dominated by neutron energies between 0.05 and 8 MeV. This facility will be based on a mixed proton/deuteron beam impinging on a thick beryllium target.A second, novel facility under development is our new neutron microbeam. The neutron microbeam will, for the first time, provide a kinematically collimated neutron beam, 10-20 micron in diameter. This facility is based on a Proton Microbeam, impinging on a thin lithium target near the threshold of the (7)Li(p,n)(7)Be reaction. This novel neutron microbeam will enable studies of neutron damage to small targets, such as single cells, individual organs within small animals or microelectronic components. PMID:22545061

  13. Novel neutron sources at the Radiological Research Accelerator Facility

    DOE PAGESBeta

    Xu, Yanping; Garty, G.; Marino, S. A.; Massey, Thomas Neal; Johnson, G. W.; Randers-Pehrson, Gerhard; Brenner, D. J.

    2012-03-16

    Since the 1960s, the Radiological Research Accelerator Facility (RARAF) has been providing researchers in biology, chemistry and physics with advanced irradiation techniques, using charged particles, photons and neutrons. We are currently developing a unique facility at RARAF, to simulate neutron spectra from an improvised nuclear device (IND), based on calculations of the neutron spectrum at 1.5 km from the epicenter of the Hiroshima atom bomb. This is significantly different from a standard fission spectrum, because the spectrum changes as the neutrons are transported through air, and is dominated by neutron energies between 0.05 and 8 MeV. This facility will bemore » based on a mixed proton/deuteron beam impinging on a thick beryllium target. A second, novel facility under development is our new neutron microbeam. The neutron microbeam will, for the first time, provide a kinematically collimated neutron beam, 10-20 micron in diameter. This facility is based on a proton microbeam, impinging on a thin lithium target near the threshold of the Li-7(p,n)Be-7 reaction. Lastly, this novel neutron microbeam will enable studies of neutron damage to small targets, such as single cells, individual organs within small animals or microelectronic components.« less

  14. Novel neutron sources at the Radiological Research Accelerator Facility

    PubMed Central

    Xu, Yanping; Garty, Guy; Marino, Stephen A.; Massey, Thomas N.; Randers-Pehrson, Gerhard; Johnson, Gary W.; Brenner, David J.

    2012-01-01

    Since the 1960s, the Radiological Research Accelerator Facility (RARAF) has been providing researchers in biology, chemistry and physics with advanced irradiation techniques, using charged particles, photons and neutrons. We are currently developing a unique facility at RARAF, to simulate neutron spectra from an improvised nuclear device (IND), based on calculations of the neutron spectrum at 1.5 km from the epicenter of the Hiroshima atom bomb. This is significantly different from a standard fission spectrum, because the spectrum changes as the neutrons are transported through air, and is dominated by neutron energies between 0.05 and 8 MeV. This facility will be based on a mixed proton/deuteron beam impinging on a thick beryllium target. A second, novel facility under development is our new neutron microbeam. The neutron microbeam will, for the first time, provide a kinematically collimated neutron beam, 10–20 micron in diameter. This facility is based on a Proton Microbeam, impinging on a thin lithium target near the threshold of the 7Li(p,n)7Be reaction. This novel neutron microbeam will enable studies of neutron damage to small targets, such as single cells, individual organs within small animals or microelectronic components. PMID:22545061

  15. Novel neutron sources at the Radiological Research Accelerator Facility

    SciTech Connect

    Xu, Yanping; Garty, G.; Marino, S. A.; Massey, Thomas Neal; Johnson, G. W.; Randers-Pehrson, Gerhard; Brenner, D. J.

    2012-03-16

    Since the 1960s, the Radiological Research Accelerator Facility (RARAF) has been providing researchers in biology, chemistry and physics with advanced irradiation techniques, using charged particles, photons and neutrons. We are currently developing a unique facility at RARAF, to simulate neutron spectra from an improvised nuclear device (IND), based on calculations of the neutron spectrum at 1.5 km from the epicenter of the Hiroshima atom bomb. This is significantly different from a standard fission spectrum, because the spectrum changes as the neutrons are transported through air, and is dominated by neutron energies between 0.05 and 8 MeV. This facility will be based on a mixed proton/deuteron beam impinging on a thick beryllium target. A second, novel facility under development is our new neutron microbeam. The neutron microbeam will, for the first time, provide a kinematically collimated neutron beam, 10-20 micron in diameter. This facility is based on a proton microbeam, impinging on a thin lithium target near the threshold of the Li-7(p,n)Be-7 reaction. Lastly, this novel neutron microbeam will enable studies of neutron damage to small targets, such as single cells, individual organs within small animals or microelectronic components.

  16. Novel neutron sources at the Radiological Research Accelerator Facility

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Garty, G.; Marino, S. A.; Massey, T. N.; Randers-Pehrson, G.; Johnson, G. W.; Brenner, D. J.

    2012-03-01

    Since the 1960s, the Radiological Research Accelerator Facility (RARAF) has been providing researchers in biology, chemistry and physics with advanced irradiation techniques, using charged particles, photons and neutrons. We are currently developing a unique facility at RARAF, to simulate neutron spectra from an improvised nuclear device (IND), based on calculations of the neutron spectrum at 1.5 km from the epicenter of the Hiroshima atom bomb. This is significantly different from a standard fission spectrum, because the spectrum changes as the neutrons are transported through air, and is dominated by neutron energies between 0.05 and 8 MeV. This facility will be based on a mixed proton/deuteron beam impinging on a thick beryllium target. A second, novel facility under development is our new neutron microbeam. The neutron microbeam will, for the first time, provide a kinematically collimated neutron beam, 10-20 micron in diameter. This facility is based on a proton microbeam, impinging on a thin lithium target near the threshold of the 7Li(p,n)7Be reaction. This novel neutron microbeam will enable studies of neutron damage to small targets, such as single cells, individual organs within small animals or microelectronic components.

  17. Modeling beam-driven and laser-driven plasma Wakefield accelerators with XOOPIC

    SciTech Connect

    Bruhwiler, David L.; Giacone, Rodolfo; Cary, John R.; Verboncoeur, John P.; Mardahl, Peter; Esarey, Eric; Leemans, Wim

    2000-06-01

    We present 2-D particle-in-cell simulations of both beam-driven and laser-driven plasma wakefield accelerators, using the object-oriented code XOOPIC, which is time explicit, fully electromagnetic, and capable of running on massively parallel supercomputers. Simulations of laser-driven wakefields with low ({approximately} 10{sup 16} W/cm{sup 2}) and high ({approximately} 10{sup 18} W/cm{sup 2}) peak intensity laser pulses are conducted in slab geometry, showing agreement with theory. Simulations of the E-157 beam wakefield experiment at the Stanford Linear Accelerator Center, in which a 30 GeV electron beam passes through 1 m of preionized lithium plasma, are conducted in cylindrical geometry, obtaining good agreement with previous work. We briefly describe some of the more significant modifications to XOOPIC required by this work, and summarize the issues relevant to modeling electron-neutral collisions in a particle-in-cell code.

  18. The sciences and applications of the Electron LINAC-driven neutron source in Argentina

    NASA Astrophysics Data System (ADS)

    Granada, J. R.; Mayer, R. E.; Dawidowski, J.; Santisteban, J. R.; Cantargi, F.; Blostein, J. J.; Rodríguez Palomino, L. A.; Tartaglione, A.

    2016-06-01

    The Neutron Physics group at Centro Atómico Bariloche (CNEA, Argentina) has evolved for more than forty five years around a small 25MeV linear electron accelerator. It constitutes our compact accelerator-driven neutron source (CANS), which is dedicated to the use and development of neutronic methods to tackle problems of basic sciences and technological applications. Its historical first commitment has been the determination of the total cross sections of materials as a function of neutron energy by means of transmission experiments for thermal and sub-thermal neutrons. This also allowed testing theoretical models for the generation of scattering kernels and cross sections. Through the years, our interests moved from classic pulsed neutron diffraction, which included the development of high-precision methods for the determination of very low hydrogen content in metals, towards deep inelastic neutron scattering (DINS), a powerful tool for the determination of atomic momentum distribution in condensed matter. More recently non-intrusive techniques aimed at the scanning of large cargo containers have started to be developed with our CANS, testing the capacity and limitations to detect special nuclear material and dangerous substances. Also, the ever-present "bremsstrahlung" radiation has been recognized and tested as a useful complement to instrumental neutron activation, as it permits to detect other nuclear species through high-energy photon activation. The facility is also used for graduate and undergraduate students' experimental work within the frame of Instituto Balseiro Physics and Nuclear Engineering courses of study, and also MSc and PhD theses work.

  19. First-order particle acceleration in magnetically driven flows

    DOE PAGESBeta

    Beresnyak, Andrey; Li, Hui

    2016-03-02

    In this study, we demonstrate that particles are regularly accelerated while experiencing curvature drift in flows driven by magnetic tension. Some examples of such flows include spontaneous turbulent reconnection and decaying magnetohydrodynamic turbulence, where a magnetic field relaxes to a lower-energy configuration and transfers part of its energy to kinetic motions of the fluid. We show that this energy transfer, which normally causes turbulent cascade and heating of the fluid, also results in a first-order acceleration of non-thermal particles. Since it is generic, this acceleration mechanism is likely to play a role in the production of non-thermal particle distribution inmore » magnetically dominant environments such as the solar chromosphere, pulsar magnetospheres, jets from supermassive black holes, and γ-ray bursts.« less

  20. First-Order Particle Acceleration in Magnetically-driven Flows

    NASA Astrophysics Data System (ADS)

    Beresnyak, Andrey; Li, Hui

    2016-03-01

    We demonstrate that particles are regularly accelerated while experiencing curvature drift in flows driven by magnetic tension. Some examples of such flows include spontaneous turbulent reconnection and decaying magnetohydrodynamic turbulence, where a magnetic field relaxes to a lower-energy configuration and transfers part of its energy to kinetic motions of the fluid. We show that this energy transfer, which normally causes turbulent cascade and heating of the fluid, also results in a first-order acceleration of non-thermal particles. Since it is generic, this acceleration mechanism is likely to play a role in the production of non-thermal particle distribution in magnetically dominant environments such as the solar chromosphere, pulsar magnetospheres, jets from supermassive black holes, and γ-ray bursts.

  1. Intense tera-hertz laser driven proton acceleration in plasmas

    NASA Astrophysics Data System (ADS)

    Sharma, A.; Tibai, Z.; Hebling, J.

    2016-06-01

    We investigate the acceleration of a proton beam driven by intense tera-hertz (THz) laser field from a near critical density hydrogen plasma. Two-dimension-in-space and three-dimension-in-velocity particle-in-cell simulation results show that a relatively long wavelength and an intense THz laser can be employed for proton acceleration to high energies from near critical density plasmas. We adopt here the electromagnetic field in a long wavelength (0.33 THz) regime in contrast to the optical and/or near infrared wavelength regime, which offers distinct advantages due to their long wavelength ( λ = 350 μ m ), such as the λ 2 scaling of the electron ponderomotive energy. Simulation study delineates the evolution of THz laser field in a near critical plasma reflecting the enhancement in the electric field of laser, which can be of high relevance for staged or post ion acceleration.

  2. Separations technology development to support accelerator-driven transmutation concepts

    SciTech Connect

    Venneri, F.; Arthur, E.; Bowman, C.

    1996-10-01

    This is the final report of a one-year Laboratory-Directed Research and Development (LDRD) Project at the Los Alamos National Laboratory (LANL). This project investigated separations technology development needed for accelerator-driven transmutation technology (ADTT) concepts, particularly those associated with plutonium disposition (accelerator-based conversion, ABC) and high-level radioactive waste transmutation (accelerator transmutation of waste, ATW). Specific focus areas included separations needed for preparation of feeds to ABC and ATW systems, for example from spent reactor fuel sources, those required within an ABC/ATW system for material recycle and recovery of key long-lived radionuclides for further transmutation, and those required for reuse and cleanup of molten fluoride salts. The project also featured beginning experimental development in areas associated with a small molten-salt test loop and exploratory centrifugal separations systems.

  3. Fast Neutron Radiography at an RFQ Accelerator System

    NASA Astrophysics Data System (ADS)

    Daniels, G. C.; Franklyn, C. B.; Dangendorf, V.; Buffler, A.; Bromberger, B.

    This work introduces the Necsa Radio Frequency Quadrupole (RFQ) accelerator facility and its work concerning fast neutron radiography (FNR). Necsa operates a 4-5 MeV, up to 50 mA deuteron RFQ. The previous deuterium gas target station has been modified to enable producing a white neutron beam employing a solid B4C target. Furthermore, the high energy beam transport (HEBT) section is under adjustment to achieve a longer flight-path and a better focus. This work presents an overview of the facility, the modifications made, and introduces past and ongoing neutron radiography investigations.

  4. Evidence of source dominance in the dynamic behavior of accelerator-driven systems

    SciTech Connect

    Rydin, R.A.; Woosley, M.L. Jr.

    1997-07-01

    In a dynamic simulation method recently developed for accelerator-driven subcritical waste transmutation systems, power levels are renormalized dynamically based on the changing reactivity of the flowing system. For such systems, the power varies directly with the source strength, and inversely with the reactivity. The prompt-jump form of the point-kinetics equations has been used to provide the dynamic renormalization factor for the spatially dependent flowing-fuel system. A unique characteristic of the source-dominated system has been discovered. In the traditional reactor system, power changes are controlled by the half-life for decay of the longest-lived delayed neutron precursors. For the source-dominated system, the delayed neutron precursors do not appreciably slow the response of the system.

  5. Linear induction accelerators for fusion and neutron production

    SciTech Connect

    Barletta, W.A. |

    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.

  6. Ion acceleration near CME-driven interplanetary shocks

    NASA Astrophysics Data System (ADS)

    Desai, Mihir; Dayeh, Maher; Smith, Charles; Mason, Glenn; Lee, Martin

    2012-05-01

    We have surveyed properties of the magnetic field power spectral densities and energetic ions and compared them with the shock normal angles of 74 CME-driven IP shocks observed at ACE and Wind during solar cycle 23. We searched for events that exhibited clear signatures of first-order Fermi acceleration at quasi-parallel shocks and shock-drift acceleration at quasi-perpendicular shocks as predicted by the diffusive shock acceleration theory. Our results show that events with clear signatures of either shock-drift or first-order Fermi acceleration at 1 AU are rare, with 64 of the 74 IP shocks (~87%) exhibiting mixed signatures. We classify the remaining ten events as follows. (1) Four quasi-perpendicular shocks with θBn>70° exhibit no enhancements in the magnetic field power spectrum around the proton gyro-frequency and a slight hardening or no change in the ~80-300 keV/nucleon CNO spectral index across the shocks, indicating the absence of upstream wave activity and the re-acceleration of a pre-existing suprathermal seed spectrum. (2) Six quasi-parallel or oblique IP shocks with θBn<70° exhibit significant enhancements in the power spectral densities around the proton gyro-frequency and are accompanied by unfolding (softening) of the ~80-300 keV/nucleon CNO spectral index across the shocks, indicating the acceleration and efficient trapping of <300 keV/nucleon CNO ions by the Alfvén waves that were most likely excited by the accelerated protons as they streamed away from the shocks. In this paper, we present contrasting energetic particle and magnetic field observations near 2 IP shocks at 1 AU to highlight the complex signatures associated with the two distinct types of shock acceleration mechanisms.

  7. Particle acceleration in axisymmetric, magnetized neutron stars

    NASA Technical Reports Server (NTRS)

    Baker, K. B.; Sturrock, P. A.

    1977-01-01

    The potential drop in the polar cap region of a rotating, magnetized neutron star is found assuming that the magnetic field is dipolar, with the field aligned (or anti-aligned) with the rotation axis. The curvature of the field lines is of critical importance. Charge flow is assumed to be along magnetic field lines. The electric field has a maximum at radius 1.5 R and the magnitude and functional form of the current is determined.

  8. Molten salt considerations for accelerator-driven subcritical fission to close the nuclear fuel cycle

    SciTech Connect

    Sooby, Elizabeth; Baty, Austin; Gerity, James; McIntyre, Peter; Melconian, Karie; Pogue, Nathaniel; Sattarov, Akhdiyor; Adams, Marvin; Tsevkov, Pavel; Phongikaroon, Supathorn; Simpson, Michael; Tripathy, Prabhat

    2013-04-19

    The host salt selection, molecular modeling, physical chemistry, and processing chemistry are presented here for an accelerator-driven subcritical fission in a molten salt core (ADSMS). The core is fueled solely with the transuranics (TRU) and long-lived fission products (LFP) from used nuclear fuel. The neutronics and salt composition are optimized to destroy the transuranics by fission and the long-lived fission products by transmutation. The cores are driven by proton beams from a strong-focusing cyclotron stack. One such ADSMS system can destroy the transuranics in the used nuclear fuel produced by a 1GWe conventional reactor. It uniquely provides a method to close the nuclear fuel cycle for green nuclear energy.

  9. SEP acceleration in CME driven shocks using a hybrid code

    SciTech Connect

    Gargaté, L.; Fonseca, R. A.; Silva, L. O.

    2014-09-01

    We perform hybrid simulations of a super-Alfvénic quasi-parallel shock, driven by a coronal mass ejection (CME), propagating in the outer coronal/solar wind at distances of between 3 to 6 solar radii. The hybrid treatment of the problem enables the study of the shock propagation on the ion timescale, preserving ion kinetics and allowing for a self-consistent treatment of the shock propagation and particle acceleration. The CME plasma drags the embedded magnetic field lines stretching from the sun, and propagates out into interplanetary space at a greater velocity than the in situ solar wind, driving the shock, and producing very energetic particles. Our results show that electromagnetic Alfvén waves are generated at the shock front. The waves propagate upstream of the shock and are produced by the counter-streaming ions of the solar wind plasma being reflected at the shock. A significant fraction of the particles are accelerated in two distinct phases: first, particles drift from the shock and are accelerated in the upstream region, and second, particles arriving at the shock get trapped and are accelerated at the shock front. A fraction of the particles diffused back to the shock, which is consistent with the Fermi acceleration mechanism.

  10. Comparison of Lead-Bismuth and Lead as Coolants for Accelerator Driven Systems

    SciTech Connect

    Bianchi, F.; Mattioda, F.; Meloni, P.

    2002-07-01

    In the framework of the Italian research program TRASCO (TRAsmutazione SCOrie, namely transmutation of radioactive wastes) and of the European research program PDS-XADS (Preliminary Design Study on an eXperimental Accelerator Driven System) the feasibility and operability of gas or liquid metal cooled accelerator driven system prototypes are currently under investigation. Initially the attention of the thermal-hydraulics group of ENEA research centre in Bologna has been focussed toward a lead-bismuth cooled subcritical system under natural or enhanced natural circulation according to the prototype design proposed. The interest in using lead as a coolant, which is characterized by a higher melting point, is explained by the need to increase the plant efficiency for the economic competitiveness, though the higher temperatures pose some technological problems. Moreover, the amount of activation products should result significantly lower. Of course the results obtained and the experience gained analysing the dynamical behaviour of the lead-bismuth cooled system cannot be directly transferred to lead cooled systems. This paper aims at presenting a preliminary comparison of lead-bismuth and lead in a simplified liquid metal cooled subcritical system, mainly from the thermal-hydraulics and system dynamics points of view. By means of the modified RELAP5 version, the dynamical behavior of a lead-bismuth or lead cooled system, which is intended to be a quite accurate representation of the Italian accelerator driven prototype XADS, has been studied. Although a more exhaustive comparison should take into account the necessarily different structural characteristics of lead-bismuth and lead cooled systems, the neutronic feedback on reactor power and also the slightly different neutronic properties of lead-bismuth and lead, the purely thermal-hydraulic analysis presented in this paper has shown that the dynamical behaviour of the XADS does not differ noticeable when lead is used

  11. A small scale accelerator driven subcritical assembly development and demonstration experiment at LAMPF

    SciTech Connect

    Wender, S.A.; Venneri, F.; Bowman, C.D.; Arthur, E.D.; Heighway, E.A.; Beard, C.A.; Bracht, R.R.; Buksa, J.J.; Chavez, W.; DeVolder, B.G.

    1994-10-01

    A small scale experiment is described that will demonstrate many of the aspects of accelerator-driven transmutation technology. This experiment uses the high-power proton beam from the Los Alamos Meson Physics Facility accelerator and will be located in the Area-A experimental hall. Beam currents of up to 1 mA will be used to produce neutrons with a molten lead target. The target is surrounded by a molten salt and graphite moderator blanket. Fissionable material can be added to the molten salt to demonstrate plutonium burning or transmutation of commercial spent fuel or energy production from thorium. The experiment will be operated at power levels up to 5 MW{sub t}.

  12. Current driven instabilities of an electromagnetically accelerated plasma

    NASA Technical Reports Server (NTRS)

    Chouetri, E. Y.; Kelly, A. J.; Jahn, R. G.

    1988-01-01

    A plasma instability that strongly influences the efficiency and lifetime of electromagnetic plasma accelerators was quantitatively measured. Experimental measurements of dispersion relations (wave phase velocities), spatial growth rates, and stability boundaries are reported. The measured critical wave parameters are in excellent agreement with theoretical instability boundary predictions. The instability is current driven and affects a wide spectrum of longitudinal (electrostatic) oscillations. Current driven instabilities, which are intrinsic to the high-current-carrying magnetized plasma of the magnetoplasmadynmic (MPD) accelerator, were investigated with a kinetic theoretical model based on first principles. Analytical limits of the appropriate dispersion relation yield unstable ion acoustic waves for T(i)/T(e) much less than 1 and electron acoustic waves for T(i)/T(e) much greater than 1. The resulting set of nonlinear equations for the case of T(i)/T(e) = 1, of most interest to the MPD thruster Plasma Wave Experiment, was numerically solved to yield a multiparameter set of stability boundaries. Under certain conditions, marginally stable waves traveling almost perpendicular to the magnetic field would travel at a velocity equal to that of the electron current. Such waves were termed current waves. Unstable current waves near the upper stability boundary were observed experimentally and are in accordance with theoretical predictions. This provides unambiguous proof of the existence of such instabilites in electromagnetic plasma accelerators.

  13. Development of an accelerating-piston implosion-driven launcher

    NASA Astrophysics Data System (ADS)

    Huneault, Justin; Loiseau, Jason; Higgins, Andrew

    2013-06-01

    The ability to soft-launch projectiles at velocities exceeding 10 km/s is of interest to several scientific fields, including orbital debris impact testing and equation of state research. Current soft-launch technologies have reached a performance plateau below this operating range. The energy and power density of high explosives provides a possible avenue to reach this velocity if used to dynamically compress a light driver gas to significantly higher pressures and temperatures compared to light-gas guns. In the implosion-driven launcher (IDL), linear implosion of a pressurized tube drives a strong shock into the gas ahead of the tube pinch, thereby forming an increasingly long column of compressed gas which can be used to propel a projectile. The McGill IDL has demonstrated the ability to launch a 0.1-g projectile to 9.1 km/s. This study focuses on the implementation of a novel launch cycle wherein the explosively driven pinch is accelerated down the length of the tube in order to maintain a relatively constant projectile base pressure early in the launch cycle. The experimental development of an accelerating driver which utilizes an explosive lens to phase the detonation wave is presented. The design and experimental performance of an accelerating-piston IDL is also discussed.

  14. Los Alamos Neutron Science Center (LANSCE) accelerator timing system upgrade

    SciTech Connect

    Rybarcyk, L.J.; Shelley, F.E. Jr.

    1997-10-01

    The Los Alamos Neutron Science Center (LANSCE) 800 MeV proton linear accelerator (linac) operates at a maximum repetition rate of twice the AC power line frequency, i.e. 120 Hz. The start of each machine cycle occurs a fixed delay after each zero-crossing of the AC line voltage. Fluctuations in the AC line frequency and phase are therefore present on all linac timing signals. Proper beam acceleration along the linac requires that the timing signals remain well synchronized to the AC line. For neutron chopper spectrometers, e.g., PHAROS at the Manuel Lujan Jr. Neutron Scattering Center, accurate neutron energy selection requires that precise synchronization be maintained between the beam-on-target arrival time and the neutron chopper rotor position. This is most easily accomplished when the chopper is synchronized to a stable, fixed frequency signal. A new zero-crossing circuit which employs a Phase-Locked Loop (PLL) has been developed to increase the phase and frequency stability of the linac timing signals and thereby improve neutron chopper performance while simultaneously maintaining proper linac operation. Results of timing signal data analysis and modeling and a description of the PLL circuit are presented.

  15. Detector positioning for the initial subcriticality level determination in accelerator-driven systems

    SciTech Connect

    Uyttenhove, W.; Van Den Eynde, G.; Baeten, P.; Kochetkov, A.; Vittiglio, G.; Wagemans, J.; Lathouwers, D.; Kloosterman, J. L.; Van Der Hagen, T. J. H. H.; Wols, F.; Billebaud, A.; Chabod, S.; Thybault, H. E.

    2012-07-01

    Within the GUINEVERE project (Generation of Uninterrupted Intense Neutrons at the lead Venus Reactor) carried out at SCK-CEN in Mol, the continuous deuteron accelerator GENEPI-3C was coupled to the VENUS-F fast simulated lead-cooled reactor. Today the FREYA project (Fast Reactor Experiments for hYbrid Applications) is ongoing to study the neutronic behavior of this Accelerator Driven System (ADS) during different phases of operation. In particular the set-up of a monitoring system for the subcriticality of an ADS is envisaged to guarantee safe operation of the installation. The methodology for subcriticality monitoring in ADS takes into account the determination of the initial subcriticality level, the monitoring of reactivity variations, and interim cross-checking. At start-up, the Pulsed Neutron Source (PNS) technique is envisaged to determine the initial subcriticality level. Thanks to its reference critical state, the PNS technique can be validated on the VENUS-F core. A detector positioning methodology for the PNS technique is set up in this paper for the subcritical VENUS-F core, based on the reduction of higher harmonics in a static evaluation of the Sjoestrand area method. A first case study is provided on the VENUS-F core. This method can be generalised in order to create general rules for detector positions and types for full-scale ADS. (authors)

  16. Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D-D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm2 is demonstrated. Estimations based on obtained experimental results show that neutron target bombarded by such deuteron beams would theoretically yield a neutron flux density up to 6·1010 cm-2/s. Thus, neutron generator based on a high-current deuteron ECR source with a powerful plasma heating by gyrotron radiation could fulfill the BNCT requirements significantly lower price, smaller size and ease of operation in comparison with existing reactors and accelerators.

  17. Current-driven plasma acceleration versus current-driven energy dissipation. I - Wave stability theory

    NASA Technical Reports Server (NTRS)

    Kelly, A. J.; Jahn, R. G.; Choueiri, E. Y.

    1990-01-01

    The dominant unstable electrostatic wave modes of an electromagnetically accelerated plasma are investigated. The study is the first part of a three-phase program aimed at characterizing the current-driven turbulent dissipation degrading the efficiency of Lorentz force plasma accelerators such as the MPD thruster. The analysis uses a kinetic theory that includes magnetic and thermal effects as well as those of an electron current transverse to the magnetic field and collisions, thus combining all the features of previous models. Analytical and numerical solutions allow a detailed description of threshold criteria, finite growth behavior, destabilization mechanisms and maximized-growth characteristics of the dominant unstable modes. The lower hybrid current-driven instability is implicated as dominant and was found to preserve its character in the collisional plasma regime.

  18. Coupling MCNP-DSP and LAHET Monte Carlo Codes for Designing Subcriticality Monitors for Accelerator-Driven Systems

    SciTech Connect

    Valentine, T.E.; Rugama, Y. Munoz-Cobos, J.; Perez, R.

    2000-10-23

    The design of reactivity monitoring systems for accelerator-driven systems must be investigated to ensure that such systems remain subcritical during operation. The Monte Carlo codes LAHET and MCNP-DSP were combined together to facilitate the design of reactivity monitoring systems. The coupling of LAHET and MCNP-DSP provides a tool that can be used to simulate a variety of subcritical measurements such as the pulsed neutron, Rossi-{alpha}, or noise analysis measurements.

  19. Transformer ratio saturation in a beam-driven wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Farmer, J. P.; Martorelli, R.; Pukhov, A.

    2015-12-01

    We show that for beam-driven wakefield acceleration, the linearly ramped, equally spaced train of bunches typically considered to optimise the transformer ratio only works for flat-top bunches. Through theory and simulation, we explain that this behaviour is due to the unique properties of the plasma response to a flat-top density profile. Calculations of the optimal scaling for a train of Gaussian bunches show diminishing returns with increasing bunch number, tending towards saturation. For a periodic bunch train, a transformer ratio of 23 was achieved for 50 bunches, rising to 40 for a fully optimised beam.

  20. Transformer ratio saturation in a beam-driven wakefield accelerator

    SciTech Connect

    Farmer, J. P.; Martorelli, R.; Pukhov, A.

    2015-12-15

    We show that for beam-driven wakefield acceleration, the linearly ramped, equally spaced train of bunches typically considered to optimise the transformer ratio only works for flat-top bunches. Through theory and simulation, we explain that this behaviour is due to the unique properties of the plasma response to a flat-top density profile. Calculations of the optimal scaling for a train of Gaussian bunches show diminishing returns with increasing bunch number, tending towards saturation. For a periodic bunch train, a transformer ratio of 23 was achieved for 50 bunches, rising to 40 for a fully optimised beam.

  1. Accelerator-driven molten-salt blankets: Physics issues

    SciTech Connect

    Houts, M.G.; Beard, C.A.; Buksa, J.J.; Davidson, J.W.; Durkee, J.W.; Perry, R.T.; Poston, D.I.

    1994-10-01

    A number of nuclear physics issues concerning the Los Alamos molten-salt accelerator-driven plutonium converter are discussed. General descriptions of several concepts using internal and external moderation are presented. Burnup and salt processing requirement calculations are presented for four concepts, indicating that both the high power density externally moderated concept and an internally moderated concept achieve total plutonium burnups approaching 90% at salt processing rates of less than 2 m{sup 3} per year. Beginning-of-life reactivity temperature coefficients and system kinetic response are also discussed. Future research should investigate the effect of changing blanket composition on operational and safety characteristics.

  2. Accelerator-driven assembly for plutonium transformation (ADAPT)

    SciTech Connect

    Van Tuyle, G.J.; Todosow, M.; Powell, J.; Schweitzer, D.

    1994-11-01

    A particle accelerator-driven spallation target and corresponding blanket region are proposed for the ultimate disposition of weapons-grade plutonium being retired from excess nuclear weapons in the US and Russia. The highly fissile plutonium is contained within .25 to .5 cm diameter silicon-carbide coated graphite beads, which are cooled by helium, within the slightly subcritical blanket region. Major advantages include very high one-pass burnup (over 90 %), a high integrity waste form (the coated beads), and operation in a subcritical mode, thereby minimizing the vulnerability to the positive reactivity feedbacks often associated with plutonium fuel.

  3. Particle Acceleration by Cme-driven Shock Waves

    NASA Technical Reports Server (NTRS)

    Reames, Donald V.

    1999-01-01

    In the largest solar energetic particle (SEP) events, acceleration occurs at shock waves driven out from the Sun by coronal mass ejections (CMEs). Peak particle intensities are a strong function of CME speed, although the intensities, spectra, and angular distributions of particles escaping the shock are highly modified by scattering on Alfven waves produced by the streaming particles themselves. Element abundances vary in complex ways because ions with different values of Q/A resonate with different parts of the wave spectrum, which varies with space and time. Just recently, we have begun to model these systematic variations theoretically and to explore other consequences of proton-generated waves.

  4. Development of the accelerator-driven energy production concept

    SciTech Connect

    Venneri, F.; Beard, C.; Bowman, C.

    1996-10-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Accelerator Driven Transmutation Technology (ADTT) offers a means of generating nuclear energy in a clean, safe way that can be attractive to the general public. However, there are issues associated with the energy story (both at the system level and technical detail) that have to be seriously addressed before the scientific community, the public, and potential industrial sponsors can be compellingly convinced of its cost/benefit.

  5. Stochastic acceleration of ions driven by Pc1 wave packets

    SciTech Connect

    Khazanov, G. V. Sibeck, D. G.; Tel'nikhin, A. A.; Kronberg, T. K.

    2015-07-15

    The stochastic motion of protons and He{sup +} ions driven by Pc1 wave packets is studied in the context of resonant particle heating. Resonant ion cyclotron heating typically occurs when wave powers exceed 10{sup −4} nT{sup 2}/Hz. Gyroresonance breaks the first adiabatic invariant and energizes keV ions. Cherenkov resonances with the electrostatic component of wave packets can also accelerate ions. The main effect of this interaction is to accelerate thermal protons to the local Alfven speed. The dependencies of observable quantities on the wave power and plasma parameters are determined, and estimates for the heating extent and rate of particle heating in these wave-particle interactions are shown to be in reasonable agreement with known empirical data.

  6. Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams

    SciTech Connect

    Schroeder, C. B.; Esarey, E.; Benedetti, C.; Toth, Cs.; Geddes, C. G. R.; Leemans, W. P.

    2010-11-04

    Plasma accelerators may be driven by the ponderomotive force of an intense laser or the space-charge force of a charged particle beam. The implications for accelerator design and the different physical mechanisms of laser-driven and beam-driven plasma acceleration are discussed. Driver propagation is examined, as well as the effects of the excited plasma wave phase velocity. The driver coupling to subsequent plasma accelerator stages for high-energy physics applications is addressed.

  7. Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams

    SciTech Connect

    Schroeder, C. B.; Esarey, E.; Benedetti, C.; Toth, Cs.; Geddes, C. G. R.; Leemans, W.P.

    2010-06-01

    Plasma accelerators may be driven by the ponderomotive force of an intense laser or the space-charge force of a charged particle beam. The implications for accelerator design and the different physical mechanisms of laser-driven and beam-driven plasma acceleration are discussed. Driver propagation is examined, as well as the effects of the excited plasma wave phase velocity. The driver coupling to subsequent plasma accelerator stages for high-energy physics applications is addressed.

  8. Conceptual design of an RFQ accelerator-based neutron source for boron neutron-capture therapy

    SciTech Connect

    Wangler, T.P.; Stovall, J.E.; Bhatia, T.S.; Wang, C.K.; Blue, T.E.; Gahbauer, R.A.

    1989-01-01

    We present a conceptual design of a low-energy neutron generator for treatment of brain tumors by boron neutron capture theory (BNCT). The concept is based on a 2.5-MeV proton beam from a radio-frequency quadrupole (RFQ) linac, and the neutrons are produced by the /sup 7/Li(p,n)/sup 7/Be reaction. A liquid lithium target and modulator assembly are designed to provide a high flux of epithermal neutrons. The patient is administered a tumor-specific /sup 10/Be-enriched compound and is irradiated by the neutrons to create a highly localized dose from the reaction /sup 10/B(n,..cap alpha..)/sup 7/Li. An RFQ accelerator-based neutron source for BNCT is compact, which makes it practical to site the facility within a hospital. 11 refs., 5 figs., 1 tab.

  9. Monte Carlo Modeling of Fast Sub-critical Assembly with MOX Fuel for Research of Accelerator-Driven Systems

    NASA Astrophysics Data System (ADS)

    Polanski, A.; Barashenkov, V.; Puzynin, I.; Rakhno, I.; Sissakian, A.

    It is considered a sub-critical assembly driven with existing 660 MeV JINR proton accelerator. The assembly consists of a central cylindrical lead target surrounded with a mixed-oxide (MOX) fuel (PuO2 + UO2) and with reflector made of beryllium. Dependence of the energetic gain on the proton energy, the neutron multiplication coefficient, and the neutron energetic spectra have been calculated. It is shown that for subcritical assembly with a mixed-oxide (MOX) BN-600 fuel (28%PuO 2 + 72%UO2) with effective density of fuel material equal to 9 g/cm 3 , the multiplication coefficient keff is equal to 0.945, the energetic gain is equal to 27, and the neutron flux density is 1012 cm˜2 s˜x for the protons with energy of 660 MeV and accelerator beam current of 1 uA.

  10. Laser-driven ion acceleration from relativistically transparent nanotargets

    NASA Astrophysics Data System (ADS)

    Hegelich, B. M.; Pomerantz, I.; Yin, L.; Wu, H. C.; Jung, D.; Albright, B. J.; Gautier, D. C.; Letzring, S.; Palaniyappan, S.; Shah, R.; Allinger, K.; Hörlein, R.; Schreiber, J.; Habs, D.; Blakeney, J.; Dyer, G.; Fuller, L.; Gaul, E.; Mccary, E.; Meadows, A. R.; Wang, C.; Ditmire, T.; Fernandez, J. C.

    2013-08-01

    Here we present experimental results on laser-driven ion acceleration from relativistically transparent, overdense plasmas in the break-out afterburner (BOA) regime. Experiments were preformed at the Trident ultra-high contrast laser facility at Los Alamos National Laboratory, and at the Texas Petawatt laser facility, located in the University of Texas at Austin. It is shown that when the target becomes relativistically transparent to the laser, an epoch of dramatic acceleration of ions occurs that lasts until the electron density in the expanding target reduces to the critical density in the non-relativistic limit. For given laser parameters, the optimal target thickness yielding the highest maximum ion energy is one in which this time window for ion acceleration overlaps with the intensity peak of the laser pulse. A simple analytic model of relativistically induced transparency is presented for plasma expansion at the time-evolving sound speed, from which these times may be estimated. The maximum ion energy attainable is controlled by the finite acceleration volume and time over which the BOA acts.

  11. Target studies for accelerator-based boron neutron capture therapy

    SciTech Connect

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

    1996-03-01

    Two new concepts, NIFTI and DISCOS, are described. These concepts enable the efficient production of epithermal neutrons for BNCT (Boron Neutron Capture Therapy) medical treatment, utilizing a low current, low energy proton beam impacting on a lithium target. The NIFTI concept uses an iron layer that strongly impedes the transmission of neutrons with energies above 24 KeV. Lower energy neutrons readily pass through this iron ``filter``, which has a deep ``window`` in its scattering cross section at 24 KeV. The DISCOS concept uses a rapidly rotating, high g disc to create a series of thin ({approximately} 1 micron thickness) liquid lithium targets in the form of continuous films through which the proton beam passes. The average energy lost by a proton as it passes through a single target is small, approximately 10 KeV. Between the targets, the proton beam is reaccelerated by an applied DC electric field. The DISCOS approach enables the accelerator -- target facility to operate with a beam energy only slightly above the threshold value for neutron production -- resulting in an output beam of low-energy epithermal neutrons -- while achieving a high yield of neutrons per milliamp of proton beam current.

  12. Development and analysis of a metal-fueled accelerator-driven burner

    SciTech Connect

    Lypsch, F.; Hill, R. N.

    1995-09-15

    The purpose of this paper is to compare the safety characteristics of an accelerator driven metal-fueled fast system to a critical core on a consistent basis to determine how these characteristics are affected solely by subcriticality of the system. To accomplish this, an accelerator proton beam/tungsten neutron source model is surrounded by a subcritical blanket using metallic fuel and sodium as coolant. The consequences of typical accident transients, namely unprotected transient overpower (TOP), loss of heat sink (LOHS), and loss of flow (LOF) were calculated for the hybrid system and compared to corresponding results for a metal-fueled fast reactor. Results indicate that the subcritical system exhibits superior performance for TOP (reactivity-induced) transients; however, only in the critical system are reactivity feedbacks able to cause passive shutdown in the LOHS and LOF events. Therefore, for a full spectrum of accident initiators considered, the overall safety behavior of accelerator-driven metal-fueled systems can neither be concluded to be worse nor to be better than advanced reactor designs which rely on passive safety features.

  13. Development and analysis of a metal-fueled accelerator-driven burner

    SciTech Connect

    Lypsch, F.; Hill, R.N.

    1994-08-01

    The purpose of this paper is to compare the safety characteristics of an accelerator driven metal fueled fast system to a critical core on a consistent basis to determine how these characteristics are affected solely by subcritically of the system. To accomplish this an accelerator proton beam/tungsten neutron source model is surrounded by a subcritical blanket using metallic fuel and sodium as coolant. The consequences of typical accident transients, namely unprotected transient overpower (TOP), loss of heat sink (LOHS), and loss of flow (LOP) were calculated for the hybrid system and compared to corresponding results for a metal-fueled fast reactor. Results indicate that the subcritical system exhibits superior performance for TOP (reactivity-induced) transits; however, only in the critical system are reactivity feedbacks able to cause passive shutdown in the LOHS ad LOP events. Therefore, for a full spectrum of accident initiators considered, the overall safety behavior of accelerator-driven metal-fueled systems can neither be concluded to be worse nor to be better than advanced reactor designs which rely on passive safety features.

  14. Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method

    DOEpatents

    Yoon, Woo Y.; Jones, James L.; Nigg, David W.; Harker, Yale D.

    1999-01-01

    A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0.times.10.sup.9 neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use.

  15. Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method

    DOEpatents

    Yoon, W.Y.; Jones, J.L.; Nigg, D.W.; Harker, Y.D.

    1999-05-11

    A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0{times}10{sup 9} neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use. 3 figs.

  16. Characterization of a Source Importance Function in an Accelerator-Driven System

    SciTech Connect

    Kim, Yonghee; Park, Won Seok; Park, Chang Kue

    2003-07-15

    An importance function of the external spallation neutrons in an accelerator-driven system (ADS) has been introduced and characterized to address the source multiplication in a subcritical blanket. For a model ADS problem with a central external source, the source importance function is evaluated with a neutron transport code system. For a homogeneous core, essential characteristics of the importance are identified from the viewpoint of spatial distributions and energy dependency, etc. The importance function is evaluated for two different beam tube diameters, and its dependency on the buffer thickness is also addressed. In order to assess the impact of the power distribution on the importance function, a heterogeneous core is considered, and its importance function is evaluated. The analyses show that the peak importance occurs in the inner fuel blanket zone, not in the central source region, and the neutron importance in a high-energy regime, above 7 to 20 MeV, is high and increases with the energy. Also, the effects of a neutron absorber on the source importance are studied, and it is found that the source importance could be drastically reduced by surrounding the source with a strong neutron absorber such as B{sub 4}C. In addition, the source importance function is compared with the conventional {lambda}-mode adjoint flux, which is used as an importance function of fission neutrons in critical reactors. The comparison reveals that the inhomogeneous source importance function could be quite similar to the homogeneous {lambda}-mode adjoint flux in both spatial and spectral distributions for a wide range of subcriticality.

  17. Solid hydrogen target for laser driven proton acceleration

    NASA Astrophysics Data System (ADS)

    Perin, J. P.; Garcia, S.; Chatain, D.; Margarone, D.

    2015-05-01

    The development of very high power lasers opens up new horizons in various fields, such as laser plasma acceleration in Physics and innovative approaches for proton therapy in Medicine. Laser driven proton acceleration is commonly based on the so-called Target Normal Sheath Acceleration (TNSA) mechanisms: a high power laser is focused onto a solid target (thin metallic or plastic foil) and interact with matter at very high intensity, thus generating a plasma; as a consequence "hot" electrons are produced and move into the forward direction through the target. Protons are generated at the target rear side, electrons try to escape from the target and an ultra-strong quasi-electrostatic field (~1TV/m) is generated. Such a field can accelerate protons with a wide energy spectrum (1-200 MeV) in a few tens of micrometers. The proton beam characteristics depend on the laser parameters and on the target geometry and nature. This technique has been validated experimentally in several high power laser facilities by accelerating protons coming from hydrogenated contaminant (mainly water) at the rear of metallic target, however, several research groups are investigating the possibility to perform experiments by using "pure" hydrogen targets. In this context, the low temperature laboratory at CEA-Grenoble has developed a cryostat able to continuously produce a thin hydrogen ribbon (from 40 to 100 microns thick). A new extrusion concept, without any moving part has been carried out, using only the thermodynamic properties of the fluid. First results and perspectives are presented in this paper.

  18. Perspectives for neutron and gamma spectroscopy in high power laser driven experiments at ELI-NP

    NASA Astrophysics Data System (ADS)

    Negoita, F.; Gugiu, M.; Petrascu, H.; Petrone, C.; Pietreanu, D.; Fuchs, J.; Chen, S.; Higginson, D.; Vassura, L.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Antici, P.; Balabanski, D.; Balascuta, S.; Cernaianu, M.; Dancus, I.; Gales, S.; Neagu, L.; Petcu, C.; Risca, M.; Toma, M.; Turcu, E.; Ursescu, D.

    2015-02-01

    The measurement of energy spectra of neutrons and gamma rays emitted by nuclei, together with charge particles spectroscopy, are the main tools for understanding nuclear phenomena occurring also in high power laser driven experiments. However, the large number of particles emitted in a very short time, in particular the strong X-rays flash produced in laser-target interaction, impose adaptation of technique currently used in nuclear physics experiment at accelerator based facilities. These aspects are discussed (Section 1) in the context of proposed studies at high power laser system of ELI-NP. Preliminary results from two experiments performed at Titan (LLNL) and ELFIE (LULI) facilities using plastic scintillators for neutron detection (Section 2) and LaBr3(Ce) scintillators for gamma detection (Section 3) are presented demonstrating the capabilities and the limitations of the employed methods. Possible improvements of these spectroscopic methods and their proposed implementation at ELI-NP will be discussed as well in the last section.

  19. Editorial: Focus on Laser- and Beam-Driven Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Joshi, Chan; Malka, Victor

    2010-04-01

    The ability of short but intense laser pulses to generate high-energy electrons and ions from gaseous and solid targets has been well known since the early days of the laser fusion program. However, during the past decade there has been an explosion of experimental and theoretical activity in this area of laser-matter interaction, driven by the prospect of realizing table-top plasma accelerators for research, medical and industrial uses, and also relatively small and inexpensive plasma accelerators for high-energy physics at the frontier of particle physics. In this focus issue on laser- and beam-driven plasma accelerators, the latest advances in this field are described. Focus on Laser- and Beam-Driven Plasma Accelerators Contents Slow wave plasma structures for direct electron acceleration B D Layer, J P Palastro, A G York, T M Antonsen and H M Milchberg Cold injection for electron wakefield acceleration X Davoine, A Beck, A Lifschitz, V Malka and E Lefebvre Enhanced proton flux in the MeV range by defocused laser irradiation J S Green, D C Carroll, C Brenner, B Dromey, P S Foster, S Kar, Y T Li, K Markey, P McKenna, D Neely, A P L Robinson, M J V Streeter, M Tolley, C-G Wahlström, M H Xu and M Zepf Dose-dependent biological damage of tumour cells by laser-accelerated proton beams S D Kraft, C Richter, K Zeil, M Baumann, E Beyreuther, S Bock, M Bussmann, T E Cowan, Y Dammene, W Enghardt, U Helbig, L Karsch, T Kluge, L Laschinsky, E Lessmann, J Metzkes, D Naumburger, R Sauerbrey, M. Scḧrer, M Sobiella, J Woithe, U Schramm and J Pawelke The optimum plasma density for plasma wakefield excitation in the blowout regime W Lu, W An, M Zhou, C Joshi, C Huang and W B Mori Plasma wakefield acceleration experiments at FACET M J Hogan, T O Raubenheimer, A Seryi, P Muggli, T Katsouleas, C Huang, W Lu, W An, K A Marsh, W B Mori, C E Clayton and C Joshi Electron trapping and acceleration on a downward density ramp: a two-stage approach R M G M Trines, R Bingham, Z Najmudin

  20. Optimization of an accelerator-based epithermal neutron source for neutron capture therapy

    SciTech Connect

    Kononov, O.E.; Kononov, V.N.; Bokhovko, M.V.; Korobeynikov, V.V.; Soloviev, A.N.; Chu, W.T.

    2004-02-20

    A modeling investigation was performed to choose moderator material and size for creating optimal epithermal neutron beams for BNCT based on a proton accelerator and the 7Li(p,n)7Be reaction as a neutrons source. An optimal configuration is suggested for the beam shaping assembly made from polytetrafluoroethylene and magnesium fluorine. Results of calculation were experimentally tested and are in good agreement with measurements.

  1. COMMISSIONING OF THE SPALLATION NEUTRON SOURCE ACCELERATOR SYSTEMS

    SciTech Connect

    Plum, Michael A

    2007-01-01

    The Spallation Neutron Source accelerator complex consists of a 2.5 MeV H- front-end injector system, a 186 MeV normal-conducting linear accelerator, a 1 GeV superconducting linear accelerator, an accumulator ring, and associated beam transport lines. The linac was commissioned in five discrete runs, starting in 2002 and completed in 2005. The accumulator ring and associated beam transport lines were commissioned in two runs from January to April 2006. With the completed commissioning of the SNS accelerator, the facility has begun initial low-power operations. In the course of beam commissioning, most beam performance parameters and beam intensity goals have been achieved at low duty factor. A number of beam dynamics measurements have been performed, including emittance evolution, transverse coupling in the ring, beam instability thresholds, and beam distributions on the target. The commissioning results, achieved beam performance and initial operating experience of the SNS will be discussed

  2. Noncommutative minisuperspace, gravity-driven acceleration, and kinetic inflation

    NASA Astrophysics Data System (ADS)

    Rasouli, S. M. M.; Moniz, Paulo Vargas

    2014-10-01

    In this paper, we introduce a noncommutative version of the Brans-Dicke (BD) theory and obtain the Hamiltonian equations of motion for a spatially flat Friedmann-Lemaître-Robertson-Walker universe filled with a perfect fluid. We focus on the case where the scalar potential as well as the ordinary matter sector are absent. Then, we investigate gravity-driven acceleration and kinetic inflation in this noncommutative BD cosmology. In contrast to the commutative case, in which the scale factor and BD scalar field are in a power-law form, in the noncommutative case the power-law scalar factor is multiplied by a dynamical exponential warp factor. This warp factor depends on the noncommutative parameter as well as the momentum conjugate associated to the BD scalar field. We show that the BD scalar field and the scale factor effectively depend on the noncommutative parameter. For very small values of this parameter, we obtain an appropriate inflationary solution, which can overcome problems within BD standard cosmology in a more efficient manner. Furthermore, a graceful exit from an early acceleration epoch towards a decelerating radiation epoch is provided. For late times, due to the presence of the noncommutative parameter, we obtain a zero acceleration epoch, which can be interpreted as the coarse-grained explanation.

  3. Ion Acceleration by Magnetic Pinch Instabilities- Powerful Neutron Sources

    NASA Astrophysics Data System (ADS)

    Hayes, Anna; Li, Hui

    2014-10-01

    Since the 1950s pinch discharges with deuterium gas have been known to produce large neutron bursts. During these early quests for laboratory fusion it was initially believed that the heat produced in the pinch led to sufficently high temperatures that these neutrons resulted from thermonuclear (TN) burn. However, a series of careful measurements led by Stirling Colgate was carried out to show that these neutrons did not result form TN burn. Rather, they resulted from an m = 0 sausage mode instability that accelerated the ions, causing beam-target interactions. Today, this same mechanism is used in dense plasma focus machines to generate intense neutron pulses for neutron activation experiments. One such experiment, to test the citicality of aging plutonium, is currently being planned at the Nevada Test Site. Helping to characterize the neutrons from the dense palsma focus to be used in this large experiment was the last applied physics project that Stirling work on. In this talk we will summarize the physics issues involved both in the original discovery in the 1950s and in today's experiments.

  4. Active Interrogation of Sensitive Nuclear Material Using Laser Driven Neutron Beams

    SciTech Connect

    Favalli, Andrea; Roth, Markus

    2015-05-01

    An investigation of the viability of a laser-driven neutron source for active interrogation is reported. The need is for a fast, movable, operationally safe neutron source which is energy tunable and has high-intensity, directional neutron production. Reasons for the choice of neutrons and lasers are set forth. Results from the interrogation of an enriched U sample are shown.

  5. Nuclear Material Detection by One-Short-Pulse-Laser-Driven Neutron Source

    SciTech Connect

    Favalli, Andrea; Aymond, F.; Bridgewater, Jon S.; Croft, Stephen; Deppert, O.; Devlin, Matthew James; Falk, Katerina; Fernandez, Juan Carlos; Gautier, Donald Cort; Gonzales, Manuel A.; Goodsell, Alison Victoria; Guler, Nevzat; Hamilton, Christopher Eric; Hegelich, Bjorn Manuel; Henzlova, Daniela; Ianakiev, Kiril Dimitrov; Iliev, Metodi; Johnson, Randall Philip; Jung, Daniel; Kleinschmidt, Annika; Koehler, Katrina Elizabeth; Pomerantz, Ishay; Roth, Markus; Santi, Peter Angelo; Shimada, Tsutomu; Swinhoe, Martyn Thomas; Taddeucci, Terry Nicholas; Wurden, Glen Anthony; Palaniyappan, Sasikumar; McCary, E.

    2015-01-28

    Covered in the PowerPoint presentation are the following areas: Motivation and requirements for active interrogation of nuclear material; laser-driven neutron source; neutron diagnostics; active interrogation of nuclear material; and, conclusions, remarks, and future works.

  6. Accelerator based epithermal neutron source for neutron capture therapy. Annual report, [October 1990--April 1991

    SciTech Connect

    Brugger, R.; Kunze, J.

    1991-05-01

    Several investigators have suggested that a charged particle accelerator with light element reactions might be able to produce enough epithermal neutrons to be useful in Neutron Capture Therapy. The reaction choice so far has been the Li(p,n) reaction with protons up to 2.5 MeV. A moderator around the target would reduce the faster neutrons down to the epithermal energy region. The goals of the present research are: identify better reactions; improve the moderators; and find better combinations of 1 and 2. The target is to achieve, at the patient location, an epithermal neutron current of greater than 10{sup 9}n/cm{sup 2}sec, with a dose to tissue from the neutrons alone of less than 10{sup {minus}10} rads/n and a dose from the gamma rays in the beam of less than 10{sup {minus}10} rads/n.

  7. A neutron producing target for BINP accelerator-based neutron source.

    PubMed

    Bayanov, B; Kashaeva, E; Makarov, A; Malyshkin, G; Samarin, S; Taskaev, S

    2009-07-01

    An innovative accelerator-based neutron source for BNCT has just started operation at the Budker Institute of Nuclear Physics, Novosibirsk. One of the main elements of the facility is a lithium target producing neutrons via the threshold (7)Li(p,n)(7)Be reaction at 25 kW proton beam with energies of 1.915 MeV or 2.5 MeV. The design of an optimal target and results of the investigation of radiation blistering of the lithium layer were presented at previous NCT Congresses. During the last two years the neutron target has been manufactured, assembled and placed in the facility. Optimization of the target is carried out with the Monte Carlo simulation code MCNP. In this article, the design of the target is discussed, results of all previous investigations are summarized, results of target testing and neutron generation are described, and results of simulation of neutron spectra are presented. PMID:19376729

  8. Effect of Driver Impedance on Dense Plasma Focus Z-Pinch Neutron Yield and Beam Acceleration

    NASA Astrophysics Data System (ADS)

    Sears, J.; Link, A.; Ellsworth, J.; Falabella, S.; Rusnak, B.; Tang, V.; Schmidt, A.; Welch, D.

    2014-10-01

    We explore the effect of driver characteristics on dense plasma focus (DPF) neutron yield and beam acceleration using particle-in-cell (PIC) simulations of a kJ-scale DPF. Our PIC simulations are fluid for the run-down phase and transition to fully kinetic for the pinch phase. The anode-cathode boundary is driven by a circuit model of the capacitive driver, including system inductance, the load of the railgap switches, the guard resistors, and the coaxial transmission line parameters. Simulations are benchmarked to measurements of a table top kJ DPF experiment with neutron yield measured with He3-based detectors. Simulated neutron yield scales approximately with the fourth power of peak current, I4. We also probe the accelerating fields by measuring the acceleration of a 4 MeV deuteron beam and by measuring the DPF self-generated beam energy distribution, finding gradients higher than 50 MV/m. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the Laboratory Directed Research and Development Program (11-ERD-063) at LLNL.

  9. Developing an Accelerator Driven System (ADS) based on electron accelerators and heavy water

    NASA Astrophysics Data System (ADS)

    Feizi, H.; Ranjbar, A. H.

    2016-02-01

    An ADS based on electron accelerators has been developed specifically for energy generation and medical applications. Monte Carlo simulations have been performed using FLUKA code to design a hybrid electron target and the core components. The composition, geometry of conversion targets and the coolant system have been optimized for electron beam energies of 20 to 100 MeV . Furthermore, the photon and photoneutron energy spectra, distribution and energy deposition for various incoming electron beam powers have been studied. Light-heavy water of various mixtures have been used as heat removal for the targets, as γ-n converters and as neutron moderators. We have shown that an electron LINAC, as a neutron production driver for ADSs, is capable of producing a neutron output of > 3.5 × 1014 (n/s/mA). Accordingly, the feasibility of an electron-based ADS employing the designed features is promising for energy generation and high intense neutron production which have various applications such as medical therapies.

  10. Treatment Planning for Accelerator-Based Boron Neutron Capture Therapy

    SciTech Connect

    Herrera, Maria S.; Gonzalez, Sara J.; Minsky, Daniel M.; Kreiner, Andres J.

    2010-08-04

    Glioblastoma multiforme and metastatic melanoma are frequent brain tumors in adults and presently still incurable diseases. Boron Neutron Capture Therapy (BNCT) is a promising alternative for this kind of pathologies. Accelerators have been proposed for BNCT as a way to circumvent the problem of siting reactors in hospitals and for their relative simplicity and lower cost among other advantages. Considerable effort is going into the development of accelerator-based BNCT neutron sources in Argentina. Epithermal neutron beams will be produced through appropriate proton-induced nuclear reactions and optimized beam shaping assemblies. Using these sources, computational dose distributions were evaluated in a real patient with diagnosed glioblastoma treated with BNCT. The simulated irradiation was delivered in order to optimize dose to the tumors within the normal tissue constraints. Using Monte Carlo radiation transport calculations, dose distributions were generated for brain, skin and tumor. Also, the dosimetry was studied by computing cumulative dose-volume histograms for volumes of interest. The results suggest acceptable skin average dose and a significant dose delivered to tumor with low average whole brain dose for irradiation times less than 60 minutes, indicating a good performance of an accelerator-based BNCT treatment.

  11. Treatment Planning for Accelerator-Based Boron Neutron Capture Therapy

    NASA Astrophysics Data System (ADS)

    Herrera, María S.; González, Sara J.; Minsky, Daniel M.; Kreiner, Andrés J.

    2010-08-01

    Glioblastoma multiforme and metastatic melanoma are frequent brain tumors in adults and presently still incurable diseases. Boron Neutron Capture Therapy (BNCT) is a promising alternative for this kind of pathologies. Accelerators have been proposed for BNCT as a way to circumvent the problem of siting reactors in hospitals and for their relative simplicity and lower cost among other advantages. Considerable effort is going into the development of accelerator-based BNCT neutron sources in Argentina. Epithermal neutron beams will be produced through appropriate proton-induced nuclear reactions and optimized beam shaping assemblies. Using these sources, computational dose distributions were evaluated in a real patient with diagnosed glioblastoma treated with BNCT. The simulated irradiation was delivered in order to optimize dose to the tumors within the normal tissue constraints. Using Monte Carlo radiation transport calculations, dose distributions were generated for brain, skin and tumor. Also, the dosimetry was studied by computing cumulative dose-volume histograms for volumes of interest. The results suggest acceptable skin average dose and a significant dose delivered to tumor with low average whole brain dose for irradiation times less than 60 minutes, indicating a good performance of an accelerator-based BNCT treatment.

  12. The calculation of the YALINA BOOSTER zero power sub critical assembly driven by external neutron sources: Brazillian contribution

    NASA Astrophysics Data System (ADS)

    Carluccio, Thiago; Rossi, Pedro Carlos Russo; Maiorino, José Rubens

    2011-08-01

    The YALINA-Booster is an experimental zero power Accelerator Driven Reactor (ADS), which consists of a sub-critical assemby driven by external neutron sources. It has a fast spectrum booster zone in the center, surrounded by a thermal one. The sub-critical core is driven by external neutron sources. Several experiments have been proposed in the framework of IAEA Coordinated Reserch Project (CRP) on ADS. This work shows results obtained by IPEN modelling and simulating experiments proposed at CRP, using the MCNP code. The comparison among our results, the experimental one and the results obtained by other participants is being done by CRP coordinators. This coolaborative work has an important role in the qualification and improvement of calculational methodologies.

  13. Accelerator-Driven Systems for Nuclear Waste Transmutation

    NASA Astrophysics Data System (ADS)

    Bowman, Charles D.

    The renewed interest since 1990 in accelerator-driven subcritical systems for transmutation of commercial nuclear waste has evolved to focus on the issue of whether fast- or thermal-spectrum systems offer greater promise. This review addresses the issue by comparing the performance of the more completely developed thermal- and fast-spectrum designs. Substantial design information is included to allow an assessment of the viability of the systems compared. The performance criteria considered most important are (a) the rapidity of reduction of the current inventory of plutonium and minor actinide from commercial spent fuel, (b) the cost, and (c) the complexity. The liquid-fueled thermal spectrum appears to offer major advantages over the solid-fueled fast-spectrum system, making waste reduction possible with about half the capital requirement on a substantially shorter time scale and with smaller separations requirements.

  14. The physics design of accelerator-driven transmutation systems

    SciTech Connect

    Venneri, F.

    1995-02-01

    Nuclear systems under study in the Los Alamos Accelerator-Driven Transmutation Technology program (ADTT) will allow the destruction of nuclear spent fuel and weapons-return plutonium, as well as the production of nuclear energy from the thorium cycle, without a long-lived radioactive waste stream. The subcritical systems proposed represent a radical departure from traditional nuclear concepts (reactors), yet the actual implementation of ADTT systems is based on modest extrapolations of existing technology. These systems strive to keep the best that the nuclear technology has developed over the years, within a sensible conservative design envelope and eventually manage to offer a safer, less expensive and more environmentally sound approach to nuclear power.

  15. Reliable-linac design for accelerator-driven subcritical reactor systems.

    SciTech Connect

    Wangler, Thomas P.,

    2002-01-01

    Accelerator reliability corresponding to a very low frequency of beam interrupts is an important new accelerator requirement for accelerator-driven subcritical reactor systems. In this paper we review typical accelerator-reliability requirements and discuss possible methods for meeting these goals with superconducting proton-linac technology.

  16. Definition and Application of Proton Source Efficiency in Accelerator-Driven Systems

    SciTech Connect

    Seltborg, Per; Wallenius, Jan; Tucek, Kamil; Gudowski, Waclaw

    2003-11-15

    In order to study the beam power amplification of an accelerator-driven system (ADS), a new parameter, the proton source efficiency {psi}* is introduced. {psi}* represents the average importance of the external proton source, relative to the average importance of the eigenmode production, and is closely related to the neutron source efficiency [varphi]*, which is frequently used in the ADS field. [varphi]* is commonly used in the physics of subcritical systems driven by any external source (spallation source, (d,d), (d,t), {sup 252}Cf spontaneous fissions, etc.). On the contrary, {psi}* has been defined in this paper exclusively for ADS studies where the system is driven by a spallation source. The main advantage with using {psi}* instead of [varphi]* for ADS is that the way of defining the external source is unique and that it is proportional to the core power divided by the proton beam power, independent of the neutron source distribution.Numerical simulations have been performed with the Monte Carlo code MCNPX in order to study {psi}* as a function of different design parameters. It was found that, in order to maximize {psi}* and therefore minimize the proton current needs, a target radius as small as possible should be chosen. For target radii smaller than {approx}30 cm, lead-bismuth is a better choice of coolant material than sodium, regarding the proton source efficiency, while for larger target radii the two materials are equally good. The optimal axial proton beam impact was found to be located {approx}20 cm above the core center. Varying the proton energy, {psi}*/E{sub p} was found to have a maximum for proton energies between 1200 and 1400 MeV. Increasing the americium content in the fuel decreases {psi}* considerably, in particular when the target radius is large.

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

    SciTech Connect

    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/sup 21/ protons have now been delivered to the spallation neutron target. Recent weekly average currents have reached 15 ..mu..A (3.2 x 10/sup 12/ protons per pulse, 30 pulses per second) and short-term peaks of almost 17 ..mu..A 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.

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

    SciTech Connect

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

    1996-07-01

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

  19. Multileaf shielding design against neutrons produced by medical linear accelerators.

    PubMed

    Rebello, W F; Silva, A X; Facure, A

    2008-01-01

    This work aims at presenting a study using Monte Carlo simulation of a Multileaf Shielding (MLS) System designed to be used for the protection of patients who undergo radiotherapy treatment, against undesired exposure to neutrons produced in the components of the medical linear accelerator heads. The choice of radiotherapy equipment as the subject of study fell on the Varian Clinac 2,100/2,300 with MLC-120 operating at 18 MeV. The general purpose Monte Carlo N-Particle radiation transport code, MCNP5, was used in the computer simulation in order to determine the ambient dose equivalent, H (10), on several points on the patient's plane, with the equipment operation with and without the MLS. The results of the simulations showed a significant neutron dose reduction after the inclusion of the proposed shielding. PMID:17569690

  20. Neutronics analysis of three beam-filter assemblies for an accelerator-based BNCT facility

    SciTech Connect

    Bleuel, D.L.; Costes, S.V.; Donahue, R.J.; Ludewigt, B.A.

    1997-08-01

    Three moderator materials, AlF{sub 3}/Al, D{sub 2}O and LiF, have been analyzed for clinical usefulness using the reaction {sup 7}Li(p,n) as an accelerator driven neutron source. Proton energies between 2.1 MeV and 2.6 MeV have been investigated. Radiation transport in the reflector/moderator assembly is simulated using the MCNP program. Depth-dose distributions in a head phanton are calculated with the BNCT-RTPE patient treatment planning program from INEEL using the MCNP generated neutron and photon spectra as the subsequent source. Clinical efficacy is compared using the current BMRR protocol for all designs. Depth-dose distributions are compared for a fixed normal tissue tolerance dose of 12.5 Gy-Eq. Radiation analyses also include a complete anthropomorphic phantom. Results of organ and whole body dose components are presented for several designs. Results indicate that high quality accelerator beams may produce clinically favorable treatments to deep-seated tumors when compared to the BMRR beam. Also discussed are problems identified in comparing accelerator and reactor based designs using in-air figures of merit as well as some results of spectrum-averaged RBE`s.

  1. Self-mode-transition from laser wakefield accelerator to plasma wakefield accelerator of laser-driven plasma-based electron acceleration

    SciTech Connect

    Pae, K. H.; Choi, I. W.; Lee, J.

    2010-12-15

    Via three-dimensional particle-in-cell simulations, the self-mode-transition of a laser-driven electron acceleration from laser wakefield to plasma-wakefield acceleration is studied. In laser wakefield accelerator (LWFA) mode, an intense laser pulse creates a large amplitude wakefield resulting in high-energy electrons. Along with the laser pulse depletion, the electron bunch accelerated in the LWFA mode drives a plasma wakefield. Then, after the plasma wakefield accelerator mode is established, electrons are trapped and accelerated in the plasma wakefield. The mode transition process and the characteristics of the accelerated electron beam are presented.

  2. COMPOSITIONALLY DRIVEN CONVECTION IN THE OCEANS OF ACCRETING NEUTRON STARS

    SciTech Connect

    Medin, Zach; Cumming, Andrew E-mail: cumming@physics.mcgill.ca

    2011-04-01

    We discuss the effect of chemical separation as matter freezes at the base of the ocean of an accreting neutron star, and argue that the retention of light elements in the liquid acts as a source of buoyancy that drives a slow but continual mixing of the ocean, enriching it substantially in light elements, and leading to a relatively uniform composition with depth. We first consider the timescales associated with different processes that can redistribute elements in the ocean, including convection, sedimentation, crystallization, and diffusion. We then calculate the steady-state structure of the ocean of a neutron star for an illustrative model in which the accreted hydrogen and helium burn to produce a mixture of O and Se. Even though the H/He burning produces only 2% oxygen by mass, the steady-state ocean has an oxygen abundance more than 10 times larger, almost 40% by mass. Furthermore, we show that the convective motions transport heat inward, with a flux of {approx}0.2 MeV nucleon{sup -1} for an O-Se ocean, heating the ocean and steepening the outward temperature gradient. The enrichment of light elements and heating of the ocean due to compositionally driven convection likely have important implications for carbon ignition models of superbursts.

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

    SciTech Connect

    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 15.6..mu..A (3.25 x 10/sup 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/sup -/ ion source which was installed in March of 1983 offered the opportunity to get above 8 ..mu..A but an instability caused unacceptable losses when attempting to operate at 10 ..mu..A 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.

  4. High-Current Experiments for Accelerator-Based Neutron Capture Therapy Applications

    SciTech Connect

    Gierga, D.P.; Klinkowstein, R.E.; Hughey, B.H.; Shefer, R.E.; Yanch, J.C.; Blackburn, B.W.

    1999-06-06

    Several accelerator-based neutron capture therapy applications are under development. These applications include boron neutron capture therapy for glioblastoma multiform and boron neutron capture synovectomy (BNCS) for rheumatoid arthritis. These modalities use accelerator-based charged-particle reactions to create a suitable neutron source. Neutrons are produced using a high-current, 2-MV terminal tandem accelerator. For these applications to be feasible, high accelerator beam currents must be routinely achievable. An effort was undertaken to explore the operating regime of the accelerator in the milliampere range. In preparation for high-current operation of the accelerator, computer simulations of charged-particle beam optics were performed to establish high-current operating conditions. Herein we describe high beam current simulations and high beam current operation of the accelerator.

  5. Experimental study on the thorium-loaded accelerator-driven system at the Kyoto Univ. critical assembly

    SciTech Connect

    Pyeon, C. H.; Yagi, T.; Lim, J. Y.; Misawa, T.

    2012-07-01

    The experimental study on the thorium-loaded accelerator-driven system (ADS) is conducted in the Kyoto Univ. Critical Assembly (KUCA). The experiments are carried out in both the critical and subcritical states for attaining the reaction rates of the thorium capture and fission reactions. In the critical system, the thorium plate irradiation experiment is carried out for the thorium capture and fission reactions. From the results of the measurements, the thorium fission reactions are obtained apparently in the critical system, and the C/E values of reaction rates show the accuracy of relative difference of about 30%. In the ADS experiments with 14 MeV neutrons and 100 MeV protons, the subcritical experiments are carried out in the thorium-loaded cores to obtain the capture reaction rates through the measurements of {sup 115}In(n, {gamma}){sup 116m}In reactions. The results of the experiments reveal the difference between the reaction rate distributions for the change in not only the neutron spectrum but also the external neutron source. The comparison between the measured and calculated reaction rate distributions demonstrates a discrepancy of the accuracy of reaction rate analyses of thorium capture reactions through the thorium-loaded ADS experiments with 14 MeV neutrons. Hereafter, kinetic experiments are planned to be carried out to deduce the delayed neutron decay constants and subcriticality using the pulsed neutron method. (authors)

  6. Application of an ultraminiature thermal neutron monitor for irradiation field study of accelerator-based neutron capture therapy

    PubMed Central

    Ishikawa, Masayori; Tanaka, Kenichi; Endo, Satrou; Hoshi, Masaharu

    2015-01-01

    Phantom experiments to evaluate thermal neutron flux distribution were performed using the Scintillator with Optical Fiber (SOF) detector, which was developed as a thermal neutron monitor during boron neutron capture therapy (BNCT) irradiation. Compared with the gold wire activation method and Monte Carlo N-particle (MCNP) calculations, it was confirmed that the SOF detector is capable of measuring thermal neutron flux as low as 105 n/cm2/s with sufficient accuracy. The SOF detector will be useful for phantom experiments with BNCT neutron fields from low-current accelerator-based neutron sources. PMID:25589504

  7. Absolute reactivity calibration of accelerator-driven systems after RACE-T experiments

    SciTech Connect

    Jammes, C. C.; Geslot, B.

    2006-07-01

    The RACE-T experiments that were held in november 2005 in the ENEA-Casaccia research center near Rome allowed us to improve our knowledge of the experimental techniques for absolute reactivity calibration at either startup or shutdown phases of accelerator-driven systems. Various experimental techniques for assessing a subcritical level were inter-compared through three different subcritical configurations SC0, SC2 and SC3, about -0.5, -3 and -6 dollars, respectively. The area-ratio method based of the use of a pulsed neutron source appears as the most performing. When the reactivity estimate is expressed in dollar unit, the uncertainties obtained with the area-ratio method were less than 1% for any subcritical configuration. The sensitivity to measurement location was about slightly more than 1% and always less than 4%. Finally, it is noteworthy that the source jerk technique using a transient caused by the pulsed neutron source shutdown provides results in good agreement with those obtained from the area-ratio technique. (authors)

  8. Biological shield design and analysis of KIPT accelerator-driven subcritical facility.

    SciTech Connect

    Zhong, Z.; Gohar, Y.; Nuclear Engineering Division

    2009-12-01

    Argonne National Laboratory of the United States and Kharkov Institute of Physics and Technology of Ukraine have been collaborating on the conceptual design development of an electron accelerator-driven subcritical facility. The facility will be utilized for performing basic and applied nuclear research, producing medical isotopes, and training young nuclear specialists. This paper presents the design and analyses of the biological shield performed for the top section of the facility. The neutron source driving the subcritical assembly is generated from the interaction of a 100-kW electron beam with a natural uranium target. The electron energy is in the range of 100 to 200 MeV, and it has a uniform spatial distribution. The shield design and the associated analyses are presented including different parametric studies. In the analyses, a significant effort was dedicated to the accurate prediction of the radiation dose outside the shield boundary as a function of the shield thickness without geometrical approximations or material homogenization. The MCNPX Monte Carlo code was utilized for the transport calculation of electrons, photons, and neutrons. Weight window variance-reduction techniques were introduced, and the dose equivalent outside the shield can be calculated with reasonably good statistics.

  9. Basis and objectives of the Los Alamos Accelerator-Driven Transmutation technology project

    NASA Astrophysics Data System (ADS)

    Bowman, Charles D.

    1995-09-01

    The Accelerator-Driven Transmutation Technology (ADTT) Project carries three approaches for dealing with waste from the defense and commercial nuclear energy enterprise. First, the problem of excess weapons plutonium in the U.S. and Russia originating both from stockpile reductions and from defense production site clean-up is one of significant current and long-term concern. The ADTT technology offers the possibility of almost complete destruction of this plutonium by fission. The technology might be particularly effective for destruction of the low quality plutonium from defense site clean-up since the system does not require the fabrication of the waste into fuel assemblies, does not require reprocessing and refabrication, and can tolerate a high level of impurities in the feed stream. Second, the ADTT system also can destroy the plutonium, other higher actinide, and long-lived fission product from commercial nuclear waste which now can only be dealt with by geologic storage. And finally, and probably most importantly the system can be used for the production of virtually unlimited electric power from thorium with concurrent destruction of its long-lived waste components so that geologic containment for them is not required. In addition plutonium is not a significant byproduct of the power generation so that non-proliferation concerns about nuclear power are almost completely eliminated. All of the ADTT systems operate with an accelerator supplementing the neutrons which in reactors are provided only by the fission process, and therefore the system can be designed to eliminate the possibility for a runaway chain reaction. The means for integration of the accelerator into nuclear power technology in order to make these benefits possible is described including estimates of accelerator operating parameters required for the three objectives.

  10. Structure Loaded Vacuum Laser-Driven Particle Acceleration Experiments at SLAC

    SciTech Connect

    Plettner, T.; Byer, R.L.; Colby, E.R.; Cowan, B.M.; Ischebeck, R.; McGuinness, C.; Lincoln, M.R.; Sears, C.M.; Siemann, R.H.; Spencer, J.E.; /SLAC /Stanford U., Phys. Dept.

    2007-04-09

    We present an overview of the future laser-driven particle acceleration experiments. These will be carried out at the E163 facility at SLAC. Our objectives include a reconfirmation of the proof-of-principle experiment, a staged buncher laser-accelerator experiment, and longer-term future experiments that employ dielectric laser-accelerator microstructures.

  11. High-value use of weapons-plutonium by burning in molten salt accelerator-driven subcritical systems or reactors

    SciTech Connect

    Bowman, C.D.; Venneri, F.

    1993-11-01

    The application of thermal-spectrum molten-salt reactors and accelerator-driven subcritical systems to the destruction of weapons-return plutonium is considered from the perspective of deriving the maximum societal benefit. The enhancement of electric power production from burning the fertile fuel {sup 232}Th with the plutonium is evaluated. Also the enhancement of destruction of the accumulated waste from commercial nuclear reactors is considered using the neutron-rich weapons plutonium. Most cases examined include the concurrent transmutation of the long-lived actinide and fission product waste ({sup 99}Tc, {sup 129}I, {sup 135}Cs, {sup 126}Sn and {sup 79}Se).

  12. Small Ground-Level Enhancement of 6 January 2014: Acceleration by CME-Driven Shock?

    NASA Astrophysics Data System (ADS)

    Li, C.; Miroshnichenko, L. I.; Sdobnov, V. E.

    2016-03-01

    Available spectral data for solar energetic particles (SEPs) measured near the Earth's orbit (GOES-13) and on the terrestrial surface (polar neutron monitors) on 6 January 2014 are analyzed. A feature of this solar proton event (SPE) and weak ground-level enhancement (GLE) is that the source was located behind the limb. For the purpose of comparison, we also use the Advanced Composition Explorer (ACE) data on sub-relativistic electrons and GOES-13 measurements of a strong and extended proton event on 8 - 9 January 2014. It was found that the surface observations at energies {>} 433 MeV and GOES-13 data at {>} 30 - {>} 700 MeV may be satisfactorily reconciled by a power-law time-of-maximum (TOM) spectrum with a characteristic exponential tail (cutoff). Some methodological difficulties of spectrum determination are discussed. Assuming that the TOM spectrum near the Earth is a proxy of the spectrum of accelerated particles in the source, we critically consider the possibility of shock acceleration to relativistic energies in the solar corona. Finally, it is suggested to interpret the observational features of this GLE under the assumption that small GLEs may be produced by shocks driven by coronal mass ejections. However, the serious limitations of such an approach to the problem of the SCR spectrum prevent drawing firm conclusions in this controversial field.

  13. Laser Driven Ion accelerators - current status and perspective

    SciTech Connect

    Zepf, M.; Robinson, A. P. L.

    2009-01-22

    The interaction of ultra-intense lasers with thin foil targets has recently emerged as a route to achieving extreme acceleration gradients and hence ultra-compact proton and ion accelerators. There are a number of distinct physical processes by which the protons/ions can be accelerated to energies in excess of 10 MeV. The recent development is discussed and a new mechanism--Radiation Pressure Acceleration is highlighted as a route to achieving efficient production of relativistic ions beams.

  14. Improved Actinide Neutron Capture Cross Sections Using Accelerator Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Bauder, W.; Pardo, R. C.; Kondev, F. G.; Kondrashev, S.; Nair, C.; Nusair, O.; Palchan, T.; Scott, R.; Seweryniak, D.; Vondrasek, R.; Collon, P.; Paul, M.; Youinou, G.; Salvatores, M.; Palmotti, G.; Berg, J.; Maddock, T.; Imel, G.

    2014-09-01

    The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are developing a technique to inject solid material into the ECR with laser ablation. With laser ablation, we can better control material injection and potentially increase efficiency in the ECR, thus creating less contamination in the source and reducing cross talk. I will present work on the laser ablation system and preliminary results from our AMS measurements. The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are

  15. Design and testing of a dc ion injector suitable for accelerator-driven transmutation

    SciTech Connect

    Schneider, J.D.; Meyer, E.; Stevens, R.R. Jr.; Hansborough, L.; Sherman, J.

    1994-08-01

    For a number of years, Los Alamos have collaborated with a team of experimentalists at Chalk River Labs who were pursuing the development of the front end of a high power cw proton accelerator. With the help of internal laboratory funding and modest defense conversion funds, we have set up and operated the accelerator at Los Alamos Operational equipment includes a slightly modified Chalk River Injector Test Stand (CRITS) including a 50 keV proton injector and a 1.25 MeV radio-frequency quadrupole (RFQ) with a klystrode rf power system. Many of the challenges involved in operating an rf linear accelerator to provide neutrons for an accelerator-driven reactor are encountered at the front (low energy) end of this system. The formation of the ion beam, the control of the beam parameters, and the focusing and matching of a highly space-charge-dominated beam are major problems. To address the operating problems in this critical front end, the Accelerator Operations and Technology Division at the Los Alamos National Laboratory has designed the APDF (Accelerator Prototype Demonstration Facility). The front end of this facility is a 75 keV, high-current, ion injector which has been assembled and is now being tested. This paper discusses the design modifications required in going from the 50 keV CRITS injector to the higher current, 75 keV injector. Major innovative changes were made in the design of this injector. This design eliminates all the control electronics and most of the ion source equipment at high potential. Also, a new, high-quality, ion-extractor system has been built. A dual-solenoid lens will be used in the low energy beam transport (LEBT) line to provide the capability of matching the extracted beam to a high-current ADTT linac. This new injector is the first piece of hardware in the APDF program and will be used to develop the long-term, reliable cw beam operation required for ADIT applications.

  16. Sensitivity Upgrades to the Idaho Accelerator Center Neutron Time of Flight Spectrometer

    SciTech Connect

    Thompson, S. J.; Kinlaw, M. T.; Harmon, J. F.; Wells, D. P.; Hunt, A. W.

    2007-10-26

    Past experiments have shown that discrimination between between fissionable and non-fissionable materials is possible using an interrogation technique that monitors for high energy prompt fission neutrons. Several recent upgrades have been made to the neutron time of flight spectrometer at the Idaho Accelerator Center with the intent of increasing neutron detection sensitivity, allowing for system use in nonproliferation and security applications.

  17. Monitoring of D-T accelerator neutron output in a PGNAA system using silicon carbide detectors

    NASA Astrophysics Data System (ADS)

    Dulloo, Abdul R.; Ruddy, Frank H.; Seidel, John G.; Petrović, Bojan

    2001-07-01

    Silicon carbide (SiC) detectors are being employed to monitor the neutron output of the D-T accelerator in a pulsed Prompt Gamma Neutron Activation Analysis (PGNAA) system. Detection of the source neutrons relies on energetic neutron reactions in the detector material. Experimental testing has been performed to confirm that the detector response is caused by fast neutrons from the accelerator source. Modeling calculations have also been carried out to provide additional verification. Use of the SiC detectors in the PGNAA system is expected to assist in evaluating system performance as well as ensuring accurate data interpretation and analysis.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  19. Perspectives for neutron and gamma spectroscopy in high power laser driven experiments at ELI-NP

    SciTech Connect

    Negoita, F. Gugiu, M. Petrascu, H. Petrone, C. Pietreanu, D.; Fuchs, J.; Chen, S.; Higginson, D.; Vassura, L.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Antici, P.; Balabanski, D.; Balascuta, S.; Cernaianu, M.; Dancus, I.; Gales, S.; Neagu, L.; Petcu, C.; and others

    2015-02-24

    The measurement of energy spectra of neutrons and gamma rays emitted by nuclei, together with charge particles spectroscopy, are the main tools for understanding nuclear phenomena occurring also in high power laser driven experiments. However, the large number of particles emitted in a very short time, in particular the strong X-rays flash produced in laser-target interaction, impose adaptation of technique currently used in nuclear physics experiment at accelerator based facilities. These aspects are discussed (Section 1) in the context of proposed studies at high power laser system of ELI-NP. Preliminary results from two experiments performed at Titan (LLNL) and ELFIE (LULI) facilities using plastic scintillators for neutron detection (Section 2) and LaBr{sub 3}(Ce) scintillators for gamma detection (Section 3) are presented demonstrating the capabilities and the limitations of the employed methods. Possible improvements of these spectroscopic methods and their proposed implementation at ELI-NP will be discussed as well in the last section.

  20. Optimizing laser-driven proton acceleration from overdense targets

    PubMed Central

    Stockem Novo, A.; Kaluza, M. C.; Fonseca, R. A.; Silva, L. O.

    2016-01-01

    We demonstrate how to tune the main ion acceleration mechanism in laser-plasma interactions to collisionless shock acceleration, thus achieving control over the final ion beam properties (e. g. maximum energy, divergence, number of accelerated ions). We investigate this technique with three-dimensional particle-in-cell simulations and illustrate a possible experimental realisation. The setup consists of an isolated solid density target, which is preheated by a first laser pulse to initiate target expansion, and a second one to trigger acceleration. The timing between the two laser pulses allows to access all ion acceleration regimes, ranging from target normal sheath acceleration, to hole boring and collisionless shock acceleration. We further demonstrate that the most energetic ions are produced by collisionless shock acceleration, if the target density is near-critical, ne ≈ 0.5 ncr. A scaling of the laser power shows that 100 MeV protons may be achieved in the PW range. PMID:27435449

  1. Optimizing laser-driven proton acceleration from overdense targets.

    PubMed

    Stockem Novo, A; Kaluza, M C; Fonseca, R A; Silva, L O

    2016-01-01

    We demonstrate how to tune the main ion acceleration mechanism in laser-plasma interactions to collisionless shock acceleration, thus achieving control over the final ion beam properties (e. g. maximum energy, divergence, number of accelerated ions). We investigate this technique with three-dimensional particle-in-cell simulations and illustrate a possible experimental realisation. The setup consists of an isolated solid density target, which is preheated by a first laser pulse to initiate target expansion, and a second one to trigger acceleration. The timing between the two laser pulses allows to access all ion acceleration regimes, ranging from target normal sheath acceleration, to hole boring and collisionless shock acceleration. We further demonstrate that the most energetic ions are produced by collisionless shock acceleration, if the target density is near-critical, ne ≈ 0.5 ncr. A scaling of the laser power shows that 100 MeV protons may be achieved in the PW range. PMID:27435449

  2. Optimizing laser-driven proton acceleration from overdense targets

    NASA Astrophysics Data System (ADS)

    Stockem Novo, A.; Kaluza, M. C.; Fonseca, R. A.; Silva, L. O.

    2016-07-01

    We demonstrate how to tune the main ion acceleration mechanism in laser-plasma interactions to collisionless shock acceleration, thus achieving control over the final ion beam properties (e. g. maximum energy, divergence, number of accelerated ions). We investigate this technique with three-dimensional particle-in-cell simulations and illustrate a possible experimental realisation. The setup consists of an isolated solid density target, which is preheated by a first laser pulse to initiate target expansion, and a second one to trigger acceleration. The timing between the two laser pulses allows to access all ion acceleration regimes, ranging from target normal sheath acceleration, to hole boring and collisionless shock acceleration. We further demonstrate that the most energetic ions are produced by collisionless shock acceleration, if the target density is near-critical, ne ≈ 0.5 ncr. A scaling of the laser power shows that 100 MeV protons may be achieved in the PW range.

  3. A neutron track etch detector for electron linear accelerators in radiotherapy

    PubMed Central

    Vukovic, Branko; Faj, Dario; Poje, Marina; Varga, Maja; Radolic, Vanja; Miklavcic, Igor; Ivkovic, Ana; Planinic, Josip

    2010-01-01

    Background Electron linear accelerators in medical radiotherapy have replaced cobalt and caesium sources of radiation. However, medical accelerators with photon energies over 10 MeV generate undesired fast neutron contamination in a therapeutic X-ray photon beam. Photons with energies above 10 MeV can interact with the atomic nucleus of a high-Z material, of which the target and the head of an accelerator consist, and lead to the neutron ejection. Results and conclusions. Our neutron dosimeter, composed of the LR-115 track etch detector and boron foil BN-1 converter, was calibrated on thermal neutrons generated in the nuclear reactor of the Josef Stefan Institute (Slovenia), and applied to dosimetry of undesirable neutrons in photon radiotherapy by the linear accelerator 15 MV Siemens Mevatron. Having considered a high dependence of a cross-section between neutron and boron on neutron energy, and broad neutron spectrum in a photon beam, as well as outside the entrance door to maze of the Mevatron, we developed a method for determining the effective neutron detector response. A neutron dose rate in the photon beam was measured to be 1.96 Sv/h. Outside the Mevatron room the neutron dose rate was 0.62 μSv/h. PACS: 87.52. Ga; 87.53.St; 29.40.Wk. PMID:22933893

  4. Characterization of a novel, short pulse laser-driven neutron sourcea)

    NASA Astrophysics Data System (ADS)

    Jung, D.; Falk, K.; Guler, N.; Deppert, O.; Devlin, M.; Favalli, A.; Fernandez, J. C.; Gautier, D. C.; Geissel, M.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Johnson, R. P.; Merrill, F.; Schaumann, G.; Schoenberg, K.; Schollmeier, M.; Shimada, T.; Taddeucci, T.; Tybo, J. L.; Wender, S. A.; Wilde, C. H.; Wurden, G. A.; Roth, M.

    2013-05-01

    We present a full characterization of a short pulse laser-driven neutron source. Neutrons are produced by nuclear reactions of laser-driven ions deposited in a secondary target. The emission of neutrons is a superposition of an isotropic component into 4π and a forward directed, jet-like contribution, with energies ranging up to 80 MeV. A maximum flux of 4.4 × 109 neutrons/sr has been observed and used for fast neutron radiography. On-shot characterization of the ion driver and neutron beam has been done with a variety of different diagnostics, including particle detectors, nuclear reaction, and time-of-flight methods. The results are of great value for future optimization of this novel technique and implementation in advanced applications.

  5. Characterization of a novel, short pulse laser-driven neutron source

    SciTech Connect

    Jung, D.; Falk, K.; Guler, N.; Devlin, M.; Favalli, A.; Fernandez, J. C.; Gautier, D. C.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Johnson, R. P.; Merrill, F.; Schoenberg, K.; Shimada, T.; Taddeucci, T.; Tybo, J. L.; Wender, S. A.; Wilde, C. H.; Wurden, G. A.; Deppert, O.; and others

    2013-05-15

    We present a full characterization of a short pulse laser-driven neutron source. Neutrons are produced by nuclear reactions of laser-driven ions deposited in a secondary target. The emission of neutrons is a superposition of an isotropic component into 4π and a forward directed, jet-like contribution, with energies ranging up to 80 MeV. A maximum flux of 4.4 × 10{sup 9} neutrons/sr has been observed and used for fast neutron radiography. On-shot characterization of the ion driver and neutron beam has been done with a variety of different diagnostics, including particle detectors, nuclear reaction, and time-of-flight methods. The results are of great value for future optimization of this novel technique and implementation in advanced applications.

  6. How to Produce a Reactor Neutron Spectrum Using a Proton Accelerator

    NASA Astrophysics Data System (ADS)

    Burns, K.; Wootan, D.; Gates, R.; Schmitt, B.; Asner, D. M.

    A method for reproducing the neutron energy spectrum present in the core of an operating nuclear reactor using an engineered target in an accelerator proton beam is proposed. The protons interact with a target to create neutrons through various (p,n) type reactions. Spectral tailoring of the emitted neutrons can be used to modify the energy of the generated neutron spectrum to represent various reactor spectra. Through the use of moderators and reflectors, the neutron spectrum can be modified to reproduce many different spectra of interest including spectra in small thermal test reactors, large pressurized water reactors, and fast reactors. The particular application of this methodology is the design of an experimental approach for using an accelerator to measure the betas produced during fission to be used to reduce uncertainties in the interpretation of reactor antineutrino measurements. This approach involves using a proton accelerator to produce a neutron field representative of a power reactor, and using this neutron field to irradiate fission foils of the primary isotopes contributing to fission in the reactor, creating unstable, neutron rich fission products that subsequently beta decay and emit electron antineutrinos. A major advantage of an accelerator neutron source over a neutron beam from a thermal reactor is that the fast neutrons can be slowed down or tailored to approximate various power reactor spectra. An accelerator based neutron source that can be tailored to match various reactor neutron spectra provides an advantage for control in studying how changes in the neutron spectra affect parameters such as the resulting fission product beta spectrum.

  7. How to produce a reactor neutron spectrum using a proton accelerator

    SciTech Connect

    Burns, Kimberly A.; Wootan, David W.; Gates, Robert O.; Schmitt, Bruce E.; Asner, David M.

    2015-01-01

    A method for reproducing the neutron energy spectrum present in the core of an operating nuclear reactor using an engineered target in an accelerator proton beam is proposed. The protons interact with a target to create neutrons through various (p,n) type reactions. Spectral tailoring of the emitted neutrons can be used to modify the energy of the generated neutron spectrum to represent various reactor spectra. Through the use of moderators and reflectors, the neutron spectrum can be modified to reproduce many different spectra of interest including spectra in small thermal test reactors, large pressurized water reactors, and fast reactors. The particular application of this methodology is the design of an experimental approach for using an accelerator to measure the betas produced during fission to be used to reduce uncertainties in the interpretation of reactor antineutrino measurements. This approach involves using a proton accelerator to produce a neutron field representative of a power reactor, and using this neutron field to irradiate fission foils of the primary isotopes contributing to fission in the reactor, creating unstable, neutron rich fission products that subsequently beta decay and emit electron antineutrinos. A major advantage of an accelerator neutron source over a neutron beam from a thermal reactor is that the fast neutrons can be slowed down or tailored to approximate various power reactor spectra. An accelerator based neutron source that can be tailored to match various reactor neutron spectra provides an advantage for control in studying how changes in the neutron spectra affect parameters such as the resulting fission product beta spectrum.

  8. Guided post-acceleration of laser-driven ions by a miniature modular structure

    NASA Astrophysics Data System (ADS)

    Kar, Satyabrata; Ahmed, Hamad; Prasad, Rajendra; Cerchez, Mirela; Brauckmann, Stephanie; Aurand, Bastian; Cantono, Giada; Hadjisolomou, Prokopis; Lewis, Ciaran L. S.; Macchi, Andrea; Nersisyan, Gagik; Robinson, Alexander P. L.; Schroer, Anna M.; Swantusch, Marco; Zepf, Matt; Willi, Oswald; Borghesi, Marco

    2016-04-01

    All-optical approaches to particle acceleration are currently attracting a significant research effort internationally. Although characterized by exceptional transverse and longitudinal emittance, laser-driven ion beams currently have limitations in terms of peak ion energy, bandwidth of the energy spectrum and beam divergence. Here we introduce the concept of a versatile, miniature linear accelerating module, which, by employing laser-excited electromagnetic pulses directed along a helical path surrounding the laser-accelerated ion beams, addresses these shortcomings simultaneously. In a proof-of-principle experiment on a university-scale system, we demonstrate post-acceleration of laser-driven protons from a flat foil at a rate of 0.5 GeV m-1, already beyond what can be sustained by conventional accelerator technologies, with dynamic beam collimation and energy selection. These results open up new opportunities for the development of extremely compact and cost-effective ion accelerators for both established and innovative applications.

  9. Development of High-Gradient Dielectric Laser-Driven Particle Accelerator Structures

    SciTech Connect

    Byer, Robert L.

    2013-11-07

    The thrust of Stanford's program is to conduct research on high-gradient dielectric accelerator structures driven with high repetition-rate, tabletop infrared lasers. The close collaboration between Stanford and SLAC (Stanford Linear Accelerator Center) is critical to the success of this project, because it provides a unique environment where prototype dielectric accelerator structures can be rapidly fabricated and tested with a relativistic electron beam.

  10. Annular beam-driven high-gradient accelerators

    SciTech Connect

    Keinigs, R.; Jones, M.E.

    1988-01-01

    During the past several years there has been an increasing interest in using wakefield acceleration techniques as a means for achieving TeV energies with the next generation of linear colliders. The principal design goals for a wakefield accelerator that is to be sued in this context are high accelerating gradients and large transformer ratios. Fundamentally any slow wave structure can function as a wakefield accelerator, and several interesting concepts have been proposed. In this paper we consider for the slow wave structure a dielectrically loaded waveguide. The Dielectric Wakefield Accelerator is a very simple device. The geometry consists of a gapless cavity filled with a dielectric. The dielectric may fill all or just part of the cavity. Here we investigate driving the system with an intense annular beam, so the dielectric is separated from the wall by a vacuum region in which this beam is propagated. The primary advantage of driving with an annular beam is that larger currents can be achieved, and thus larger accelerating gradients can be generated. The drive beam is stabilized by a strong, axial magnetic field. The wall is coated with a dielectric liner to provide for better coupling. A small hole is drilled in the center of the dielectric to allow for the passage of a low current, witness beam.

  11. Fusion-neutron measurements for magnetized liner inertial fusion experiments on the Z accelerator

    NASA Astrophysics Data System (ADS)

    Hahn, K. D.; Chandler, G. A.; Ruiz, C. L.; Cooper, G. W.; Gomez, M. R.; Slutz, S.; Sefkow, A. B.; Sinars, D. B.; Hansen, S. B.; Knapp, P. F.; Schmit, P. F.; Harding, E.; Jennings, C. A.; Awe, T. J.; Geissel, M.; Rovang, D. C.; Torres, J. A.; Bur, J. A.; Cuneo, M. E.; Glebov, V. Yu; Harvey-Thompson, A. J.; Herrman, M. C.; Hess, M. H.; Johns, O.; Jones, B.; Lamppa, D. C.; Lash, J. S.; Martin, M. R.; McBride, R. D.; Peterson, K. J.; Porter, J. L.; Reneker, J.; Robertson, G. K.; Rochau, G. A.; Savage, M. E.; Smith, I. C.; Styron, J. D.; Vesey, R. A.

    2016-05-01

    Several magnetized liner inertial fusion (MagLIF) experiments have been conducted on the Z accelerator at Sandia National Laboratories since late 2013. Measurements of the primary DD (2.45 MeV) neutrons for these experiments suggest that the neutron production is thermonuclear. Primary DD yields up to 3e12 with ion temperatures ∼2-3 keV have been achieved. Measurements of the secondary DT (14 MeV) neutrons indicate that the fuel is significantly magnetized. Measurements of down-scattered neutrons from the beryllium liner suggest ρRliner∼1g/cm2. Neutron bang times, estimated from neutron time-of-flight (nTOF) measurements, coincide with peak x-ray production. Plans to improve and expand the Z neutron diagnostic suite include neutron burn-history diagnostics, increased sensitivity and higher precision nTOF detectors, and neutron recoil-based yield and spectral measurements.

  12. Burnup calculations for KIPT accelerator driven subcritical facility using Monte Carlo computer codes-MCB and MCNPX.

    SciTech Connect

    Gohar, Y.; Zhong, Z.; Talamo, A.; Nuclear Engineering Division

    2009-06-09

    Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the conceptual design development of an electron accelerator driven subcritical (ADS) facility, using the KIPT electron accelerator. The neutron source of the subcritical assembly is generated from the interaction of 100 KW electron beam with a natural uranium target. The electron beam has a uniform spatial distribution and electron energy in the range of 100 to 200 MeV. The main functions of the subcritical assembly are the production of medical isotopes and the support of the Ukraine nuclear power industry. Neutron physics experiments and material structure analyses are planned using this facility. With the 100 KW electron beam power, the total thermal power of the facility is {approx}375 kW including the fission power of {approx}260 kW. The burnup of the fissile materials and the buildup of fission products reduce continuously the reactivity during the operation, which reduces the neutron flux level and consequently the facility performance. To preserve the neutron flux level during the operation, fuel assemblies should be added after long operating periods to compensate for the lost reactivity. This process requires accurate prediction of the fuel burnup, the decay behavior of the fission produces, and the introduced reactivity from adding fresh fuel assemblies. The recent developments of the Monte Carlo computer codes, the high speed capability of the computer processors, and the parallel computation techniques made it possible to perform three-dimensional detailed burnup simulations. A full detailed three-dimensional geometrical model is used for the burnup simulations with continuous energy nuclear data libraries for the transport calculations and 63-multigroup or one group cross sections libraries for the depletion calculations. Monte Carlo Computer code MCNPX and MCB are utilized for this study. MCNPX transports the

  13. AWAKE, The Advanced Proton Driven Plasma Wakefield Acceleration Experiment at CERN

    NASA Astrophysics Data System (ADS)

    Gschwendtner, E.; Adli, E.; Amorim, L.; Apsimon, R.; Assmann, R.; Bachmann, A.-M.; Batsch, F.; Bauche, J.; Berglyd Olsen, V. K.; Bernardini, M.; Bingham, R.; Biskup, B.; Bohl, T.; Bracco, C.; Burrows, P. N.; Burt, G.; Buttenschön, B.; Butterworth, A.; Caldwell, A.; Cascella, M.; Chevallay, E.; Cipiccia, S.; Damerau, H.; Deacon, L.; Dirksen, P.; Doebert, S.; Dorda, U.; Farmer, J.; Fedosseev, V.; Feldbaumer, E.; Fiorito, R.; Fonseca, R.; Friebel, F.; Gorn, A. A.; Grulke, O.; Hansen, J.; Hessler, C.; Hofle, W.; Holloway, J.; Hüther, M.; Jaroszynski, D.; Jensen, L.; Jolly, S.; Joulaei, A.; Kasim, M.; Keeble, F.; Li, Y.; Liu, S.; Lopes, N.; Lotov, K. V.; Mandry, S.; Martorelli, R.; Martyanov, M.; Mazzoni, S.; Mete, O.; Minakov, V. A.; Mitchell, J.; Moody, J.; Muggli, P.; Najmudin, Z.; Norreys, P.; Öz, E.; Pardons, A.; Pepitone, K.; Petrenko, A.; Plyushchev, G.; Pukhov, A.; Rieger, K.; Ruhl, H.; Salveter, F.; Savard, N.; Schmidt, J.; Seryi, A.; Shaposhnikova, E.; Sheng, Z. M.; Sherwood, P.; Silva, L.; Soby, L.; Sosedkin, A. P.; Spitsyn, R. I.; Trines, R.; Tuev, P. V.; Turner, M.; Verzilov, V.; Vieira, J.; Vincke, H.; Wei, Y.; Welsch, C. P.; Wing, M.; Xia, G.; Zhang, H.

    2016-09-01

    The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment at CERN and the world's first proton driven plasma wakefield acceleration experiment. The AWAKE experiment will be installed in the former CNGS facility and uses the 400 GeV/c proton beam bunches from the SPS. The first experiments will focus on the self-modulation instability of the long (rms ~12 cm) proton bunch in the plasma. These experiments are planned for the end of 2016. Later, in 2017/2018, low energy (~15 MeV) electrons will be externally injected into the sample wakefields and be accelerated beyond 1 GeV. The main goals of the experiment will be summarized. A summary of the AWAKE design and construction status will be presented.

  14. Inverse free electron lasers and laser wakefield acceleration driven by CO2 lasers.

    PubMed

    Kimura, W D; Andreev, N E; Babzien, M; Ben-Zvi, I; Cline, D B; Dilley, C E; Gottschalk, S C; Hooker, S M; Kusche, K P; Kuznetsov, S V; Pavlishin, I V; Pogorelsky, I V; Pogosova, A A; Steinhauer, L C; Ting, A; Yakimenko, V; Zigler, A; Zhou, F

    2006-03-15

    The staged electron laser acceleration (STELLA) experiment demonstrated staging between two laser-driven devices, high trapping efficiency of microbunches within the accelerating field and narrow energy spread during laser acceleration. These are important for practical laser-driven accelerators. STELLA used inverse free electron lasers, which were chosen primarily for convenience. Nevertheless, the STELLA approach can be applied to other laser acceleration methods, in particular, laser-driven plasma accelerators. STELLA is now conducting experiments on laser wakefield acceleration (LWFA). Two novel LWFA approaches are being investigated. In the first one, called pseudo-resonant LWFA, a laser pulse enters a low-density plasma where nonlinear laser/plasma interactions cause the laser pulse shape to steepen, thereby creating strong wakefields. A witness e-beam pulse probes the wakefields. The second one, called seeded self-modulated LWFA, involves sending a seed e-beam pulse into the plasma to initiate wakefield formation. These wakefields are amplified by a laser pulse following shortly after the seed pulse. A second e-beam pulse (witness) follows the seed pulse to probe the wakefields. These LWFA experiments will also be the first ones driven by a CO(2) laser beam. PMID:16483952

  15. Ultrashort laser pulse driven inverse free electron laser accelerator experiment

    NASA Astrophysics Data System (ADS)

    Moody, J. T.; Anderson, S. G.; Anderson, G.; Betts, S.; Fisher, S.; Tremaine, A.; Musumeci, P.

    2016-02-01

    In this paper we discuss the ultrashort pulse high gradient inverse free electron laser accelerator experiment carried out at the Lawrence Livermore National Laboratory which demonstrated gradients exceeding 200 MV /m using a 4 TW 100 fs long 800 nm Ti :Sa laser pulse. Due to the short laser and electron pulse lengths, synchronization was determined to be one of the main challenges in this experiment. This made necessary the implementation of a single-shot, nondestructive, electro-optic sampling based diagnostics to enable time-stamping of each laser accelerator shot with <100 fs accuracy. The results of this experiment are expected to pave the way towards the development of future GeV-class IFEL accelerators.

  16. Laser-driven multicharged heavy ion beam acceleration

    NASA Astrophysics Data System (ADS)

    Nishiuchi, M.; Sakaki, H.; Esirkepov, T. Z.; Nishio, K.; Pikuz, T. A.; Faenov, A. Y.; Pirozhkov, A. S.; Sagisaka, A.; Ogura, K.; Kanasaki, M.; Kiriyama, H.; Fukuda, Y.; Kando, M.; Yamauchi, T.; Watanabe, Y.; Bulanov, S. V.; Kondo, K.; Imai, K.; Nagamiya, S.

    2015-05-01

    Experimental demonstration of multi-charged heavy ion acceleration from the interaction between the ultra-intense short pulse laser system and the metal target is presented. The laser pulse of <10 J laser energy, 36 fs pulse width, and the contrast level of ~1010 from 200 TW class Ti:sapphire J-KAREN laser system at JAEA is used in the experiment. Almost fully stripped Fe ions accelerated up to 0.9 GeV are demonstrated. This is achieved by the high intensity laser field of ˜ 1021Wcm-2 interacting with the solid density target. The demonstrated iron ions with high charge to mass ratio (Q/M) is difficult to be achieved by the conventional heavy ion source technique in the accelerators.

  17. Estimation of thermal neutron fluences in the concrete of proton accelerator facilities from 36Cl production

    NASA Astrophysics Data System (ADS)

    Bessho, K.; Matsumura, H.; Miura, T.; Wang, Q.; Masumoto, K.; Hagura, H.; Nagashima, Y.; Seki, R.; Takahashi, T.; Sasa, K.; Sueki, K.; Matsuhiro, T.; Tosaki, Y.

    2007-06-01

    The thermal neutron fluence that poured into the shielding concrete of proton accelerator facilities was estimated from the in situ production of 36Cl. The thermal neutron fluences at concrete surfaces during 10-30 years of operation were in the range of 1012-1014 n/cm2. The maxima in thermal neutron fluences were observed at ≈5-15 cm in the depths analyzed for 36Cl/35Cl by AMS. These characteristics imply that thermalization of neutrons occurred inside the concrete. Compared to the several tens of MeV cyclotrons, secondary neutrons penetrate deeper into the concrete at the high-energy accelerators possessing acceleration energies of 400 MeV and 12 GeV. The attenuation length of neutrons reflects the energy spectra of secondary neutrons emitted by the nuclear reaction at the beam-loss points. Increasing the energy of secondary neutrons shifts the maximum in the thermal neutron fluences to deeper positions. The data obtained in this study will be useful for the radioactive waste management at accelerator facilities.

  18. How dogs lap: open pumping driven by acceleration

    NASA Astrophysics Data System (ADS)

    Gart, Sean; Socha, John; Vlachos, Pavlos; Jung, Sunghwan

    2015-11-01

    Dogs drink by lapping because they have incomplete cheeks and cannot suck fluids into the mouth. When lapping, a dog's tongue pulls a liquid column from a bath, which is then swallowed, suggesting that the hydrodynamics of column formation are critical to understanding how dogs drink. We measured the kinematics of lapping from nineteen dogs and used the results to generate a physical model of the tongue's interaction with the air-fluid interface. These experiments with an accelerating rod help to explain how dogs exploit the fluid dynamics of the generated column. The results suggest that effects of acceleration govern lapping frequency, and that dogs curl the tongue ventrally (backwards) and time their bite on the column to increase fluid intake per lap. Comparing lapping in dogs and cats reveals that though they both lap with the same frequency scaling with respect to body mass and have similar morphology, these carnivores lap in different physical regimes: a high-acceleration regime for dogs and a low-acceleration regime for cats.

  19. Constant Acceleration: Experiments with a Fan-Driven Dynamics Cart.

    ERIC Educational Resources Information Center

    Morse, Robert A.

    1993-01-01

    Describes the rebuilding of a Project Physics fan cart on a PASCO dynamics cart chassis for achieving greatly reduced frictional forces. Suggests four experiments for the rebuilt cart: (1) acceleration on a level track, (2) initial negative velocity, (3) different masses and different forces, and (4) inclines. (MVL)

  20. The ram accelerator - A chemically driven mass launcher

    NASA Technical Reports Server (NTRS)

    Kaloupis, P.; Bruckner, A. P.

    1988-01-01

    The ram accelerator, a chemically propelled mass driver, is presented as a viable new approach for directly launching acceleration-insensitive payloads into low earth orbit. The propulsion principle is similar to that of a conventional air-breathing ramjet. The cargo vehicle resembles the center-body of a ramjet and travels through a tube filled with a pre-mixed fuel and oxidizer mixture. The launch tube acts as the outer cowling of the ramjet and the combustion process travels with the vehicle. Two drive modes of the ram accelerator propulsion system are described, which when used in sequence are capable of accelerating the vehicle to as high as 10 km/sec. The requirements are examined for placing a 2000 kg vehicle into a 500 km orbit with a minimum of on-board rocket propellant for circularization maneuvers. It is shown that aerodynamic heating during atmospheric transit results in very little ablation of the nose. An indirect orbital insertion scenario is selected, utilizing a three step maneuver consisting of two burns and aerobraking. An on-board propulsion system using storable liquid propellants is chosen in order to minimize propellant mass requirements, and the use of a parking orbit below the desired final orbit is suggested as a means to increase the flexibility of the mass launch concept. A vehicle design using composite materials is proposed that will best meet the structural requirements, and a preliminary launch tube design is presented.

  1. Undulator radiation driven by laser-wakefield accelerator electron beams

    NASA Astrophysics Data System (ADS)

    Wiggins, S. M.; Anania, M. P.; Welsh, G. H.; Brunetti, E.; Cipiccia, S.; Grant, P. A.; Reboredo, D.; Manahan, G.; Grant, D. W.; Jaroszynski, D. A.

    2015-05-01

    The Advanced Laser-Plasma High-Energy Accelerators towards X-rays (ALPHA-X) programme is developing laserplasma accelerators for the production of ultra-short electron bunches with subsequent generation of coherent, bright, short-wavelength radiation pulses. The new Scottish Centre for the Application of Plasma-based Accelerators (SCAPA) will develop a wide range of applications utilising such light sources. Electron bunches can be propagated through a magnetic undulator with the aim of generating fully coherent free-electron laser (FEL) radiation in the ultra-violet and Xrays spectral ranges. Demonstration experiments producing spontaneous undulator radiation have been conducted at visible and extreme ultra-violet wavelengths but it is an on-going challenge to generate and maintain electron bunches of sufficient quality in order to stimulate FEL behaviour. In the ALPHA-X beam line experiments, a Ti:sapphire femtosecond laser system with peak power 20 TW has been used to generate electron bunches of energy 80-150 MeV in a 2 mm gas jet laser-plasma wakefield accelerator and these bunches have been transported through a 100 period planar undulator. High peak brilliance, narrow band spontaneous radiation pulses in the vacuum ultra-violet wavelength range have been generated. Analysis is provided with respect to the magnetic quadrupole beam transport system and subsequent effect on beam emittance and duration. Requirements for coherent spontaneous emission and FEL operation are presented.

  2. Disk-accreting magnetic neutron stars as high-energy particle accelerators

    NASA Technical Reports Server (NTRS)

    Hamilton, Russell J.; Lamb, Frederick K.; Miller, M. Coleman

    1994-01-01

    Interaction of an accretion disk with the magnetic field of a neutron star produces large electromotive forces, which drive large conduction currents in the disk-magnetosphere-star circuit. Here we argue that such large conduction currents will cause microscopic and macroscopic instabilities in the magnetosphere. If the minimum plasma density in the magnetosphere is relatively low is less than or aproximately 10(exp 9)/cu cm, current-driven micro-instabilities may cause relativistic double layers to form, producing voltage differences in excess of 10(exp 12) V and accelerating charged particles to very high energies. If instead the plasma density is higher (is greater than or approximately = 10(exp 9)/cu cm, twisting of the stellar magnetic field is likely to cause magnetic field reconnection. This reconnection will be relativistic, accelerating plasma in the magnetosphere to relativistic speeds and a small fraction of particles to very high energies. Interaction of these high-energy particles with X-rays, gamma-rays, and accreting plasma may produce detectable high-energy radiation.

  3. Electron acceleration driven by ultrashort and nonparaxial radially polarized laser pulses.

    PubMed

    Marceau, Vincent; April, Alexandre; Piché, Michel

    2012-07-01

    Exact closed-form solutions to Maxwell's equations are used to investigate the acceleration of electrons in vacuum driven by ultrashort and nonparaxial radially polarized laser pulses. We show that the threshold power above which significant acceleration takes place is greatly reduced by using a tighter focus. Moreover, electrons accelerated by tightly focused single-cycle laser pulses may reach around 80% of the theoretical energy gain limit, about twice the value previously reported with few-cycle paraxial pulses. Our results demonstrate that the direct acceleration of electrons in vacuum is well within reach of current laser technology. PMID:22743415

  4. Effect of plasma inhomogeneity on plasma wakefield acceleration driven by long bunches

    SciTech Connect

    Lotov, K. V.; Pukhov, A.; Caldwell, A.

    2013-01-15

    Effects of plasma inhomogeneity on self-modulating proton bunches and accelerated electrons were studied numerically. The main effect is the change of the wakefield wavelength which results in phase shifts and loss of accelerated particles. This effect imposes severe constraints on density uniformity in plasma wakefield accelerators driven by long particle bunches. The transverse two stream instability that transforms the long bunch into a train of micro-bunches is less sensitive to density inhomogeneity than are the accelerated particles. The bunch freely passes through increased density regions and interacts with reduced density regions.

  5. Positron acceleration in plasma bubble wakefield driven by an ultraintense laser

    NASA Astrophysics Data System (ADS)

    Hou, Ya-Juan; Wan, Feng; Sang, Hai-Bo; Xie, Bai-Song

    2016-01-01

    The dynamics of positrons accelerating in electron-positron-ion plasma bubble fields driven by an ultraintense laser is investigated. The bubble wakefield is obtained theoretically when laser pulses are propagating in the electron-positron-ion plasma. To restrict the positrons transversely, an electron beam is injected. Acceleration regions and non-acceleration ones of positrons are obtained by the numerical simulation. It is found that the ponderomotive force causes the fluctuation of the positrons momenta, which results in the trapping of them at a lower ion density. The energy gaining of the accelerated positrons is demonstrated, which is helpful for practical applications.

  6. Optimizing Laser-accelerated Ion Beams for a Collimated Neutron Source

    SciTech Connect

    C.L. Ellison and J. Fuchs

    2010-09-23

    High-flux neutrons for imaging and materials analysis applications have typically been provided by accelerator- and reactor-based neutron sources. A novel approach is to use ultraintense (>1018W/cm2) lasers to generate picosecond, collimated neutrons from a dual target configuration. In this article, the production capabilities of present and upcoming laser facilities are estimated while independently maximizing neutron yields and minimizing beam divergence. A Monte-Carlo code calculates angular and energy distributions of neutrons generated by D-D fusion events occurring within a deuterated target for a given incident beam of D+ ions. Tailoring of the incident distribution via laser parameters and microlens focusing modifies the emerging neutrons. Projected neutron yields and distributions are compared to conventional sources, yielding comparable on-target fluxes per discharge, shorter time resolution, larger neutron energies and greater collimation.

  7. Neutron dose per fluence and weighting factors for use at high energy accelerators

    SciTech Connect

    Cossairt, J.Donald; Vaziri, Kamran; /Fermilab

    2008-07-01

    In June 2007, the United States Department of Energy incorporated revised values of neutron weighting factors into its occupational radiation protection Regulation 10 CFR Part 835 as part of updating its radiation dosimetry system. This has led to a reassessment of neutron radiation fields at high energy proton accelerators such as those at the Fermi National Accelerator Laboratory (Fermilab). Values of dose per fluence factors appropriate for accelerator radiation fields calculated elsewhere are collated and radiation weighting factors compared. The results of this revision to the dosimetric system are applied to americium-beryllium neutron energy spectra commonly used for instrument calibrations. A set of typical accelerator neutron energy spectra previously measured at Fermilab are reassessed in light of the new dosimetry system. The implications of this revision are found to be of moderate significance.

  8. Acceleration of neutrons in a scheme of a tautochronous mathematical pendulum (physical principles)

    SciTech Connect

    Rivlin, Lev A

    2010-12-09

    We consider the physical principles of neutron acceleration through a multiple synchronous interaction with a gradient rf magnetic field in a scheme of a tautochronous mathematical pendulum. (laser applications and other aspects of quantum electronics)

  9. NONDESTRUCTIVE IDENTIFICATION OF CHEMICAL WARFARE AGENTS AND EXPLOSIVES BY NEUTRON GENERATOR-DRIVEN PGNAA

    SciTech Connect

    T. R. Twomey; A. J. Caffrey; D. L. Chichester

    2007-02-01

    Prompt gamma-ray neutron activation analysis (PGNAA) is now a proven method for the identification of chemical warfare agents and explosives in military projectiles and storage containers. Idaho National Laboratory is developing a next-generation PGNAA instrument based on the new Ortec Detective mechanically-cooled HPGe detector and a neutron generator. In this paper we review PGNAA analysis of suspect chemical warfare munitions, and we discuss the advantages and disadvantages of replacing the californium-252 radioisotopic neutron source with a compact accelerator neutron generator.

  10. E-Beam Driven Accelerators: Working Group Summary

    SciTech Connect

    Muggli, P.; Ng, J.S.T.; /SLAC

    2005-07-12

    The working group has identified the parameters of an afterburner based on the design of a future linear collider. The new design brings the center of mass energy of the collider from 1 to 2 TeV. The afterburner is located in the final focus section of the collider, operates at a gradient of {approx}4 GeV/m, and is only about 125 m long. Very important issues remain to be addressed, and include the physics and design of the positron side of the afterburner, as well as of the final focus system. Present plasma wakefield accelerator experiments have reached a level of maturity and of relevance to the afterburner, that make it timely to involve the high energy physics and accelerator community in the afterburner design process. The main result of this working group is the first integration of the designs of a future linear collider and an afterburner.

  11. e-Beam Driven Accelerators: Working Group Summary

    SciTech Connect

    Muggli, P.; Ng, J.S.T.

    2004-12-07

    The working group has identified the parameters of an afterburner based on the design of a future linear collider. The new design brings the center of mass energy of the collider from 1 to 2 TeV. The afterburner is located in the final focus section of the collider, operates at a gradient of {approx_equal}4 GeV/m, and is only about 125 m long. Very important issues remain to be addressed, and include the physics and design of the positron side of the afterburner, as well as of the final focus system. Present plasma wakefield accelerator experiments have reached a level of maturity and of relevance to the afterburner, that make it timely to involve the high energy physics and accelerator community in the afterburner design process. The main result of this working group is the first integration of the designs of a future linear collider and an afterburner.

  12. Characteristics of laser-driven electron acceleration invacuum

    SciTech Connect

    Wang, P.X.; Ho, Y.K.; Yuan, X.Q.; Kong, Q.; Sessler, A.M.; Esarey, E.; Moshkovich, E.; Nishida, Y.; Yugami, N.; Ito, H.; Wang, J.X.; Scheid, S.

    2001-11-01

    The interaction of free electrons with intense laser beamsin vacuum is studied using a 3D test particle simulation model thatsolves the relativistic Newton-Lorentz equations of motion inanalytically specified laser fields. Recently, a group of solutions wasfound for very intense laser fields that show interesting and unusualcharacteristics. In particular, it was found that an electron can becaptured within the high-intensity laser region, rather than expelledfrom it, and the captured electron can be accelerated to GeV energieswith acceleration gradients on the order of tens of GeV/cm. Thisphenomenon is termed the capture and acceleration scenario (CAS) and isstudied in detail in this paper. The maximum net energy exchange by theCAS mechanism is found to be approximately proportional to a 2_o, in theregime where a_o>100, where a_o = eE_o/m_ewc is a dimensionlessparameter specifying the magnitude of the laser field. The acceleratedGeV electron bunch is a macro-pulse, with duration equal or less thanthat of the laser pulse, which is composed of many micro-pulses that areperiodic at the laser frequency. The energy spectrum of the CAS electronbunch is presented. The dependence of the energy exchange in the CAS onvarious parameters, e.g., a 2_o (laser intensity), w_o (laser radius atfocus), tao (laser pulse duration), b_o (the impact parameter), andtheta_i (the injection angle with respect to the laser propagationdirection), are explored in detail. A comparison with diverse theoreticalmodels is also presented, including a classical model based on phasevelocities and a quantum model based on nonlinear Comptonscattering.

  13. Direct evidence for inelastic neutron 'acceleration' by {sup 177}Lu{sup m}

    SciTech Connect

    Roig, O.; Meot, V.; Rosse, B.; Belier, G.; Daugas, J.-M.; Morel, P.; Letourneau, A.; Menelle, A.

    2011-06-15

    The inelastic neutron acceleration cross section on the long-lived metastable state of {sup 177}Lu has been measured using a direct method. High-energy neutrons have been detected using a specially designed setup placed on a cold neutron beam extracted from the ORPHEE reactor in Saclay. The 146{+-}19 b inelastic neutron acceleration cross section in the ORPHEE cold neutron flux confirms the high cross section for this process on the {sup 177}Lu{sup m} isomer. The deviation from the 258{+-}58 b previously published obtained for a Maxwellian neutron flux at a 323 K temperature could be explained by the presence of a low energy resonance. Resonance parameters are deduced and discussed.

  14. Advances in laser driven accelerator R&D

    SciTech Connect

    Leemans, Wim

    2004-08-23

    Current activities (last few years) at different laboratories, towards the development of a laser wakefield accelerator (LWFA) are reviewed, followed by a more in depth discussion of results obtained at the L'OASIS laboratory of LBNL. Recent results on laser guiding of relativistically intense beams in preformed plasma channels are discussed. The observation of mono-energetic beams in the 100 MeV energy range, produced by a channel guided LWFA at LBNL, is described and compared to results obtained in the unguided case at LOA, RAL and LBNL. Analysis, aided by particle-in-cell simulations, as well as experiments with various plasma lengths and densities, indicate that tailoring the length of the accelerator has a very beneficial impact on the electron energy distribution. Progress on laser triggered injection is reviewed. Results are presented on measurements of bunch duration and emittance of the accelerated electron beams, that indicate the possibility of generating femtosecond duration electron bunches. Future challenges and plans towards the development of a 1 GeV LWFA module are discussed.

  15. Interaction of neutrons with a birefringent medium moving with an acceleration

    NASA Astrophysics Data System (ADS)

    Frank, A. I.

    2016-04-01

    Recent experiments demonstrated that the energy of a neutron traversing an accelerated sample of a refractive medium changes. Later, it was realized that such an accelerated-medium effect (AME) is quite a general phenomenon. This paper discusses some special features of the effect for a birefringent medium. In this case, AME shows quite new features. In neutron optics, where birefringence is due to the spin dependence of the refractive index, AME results in a nonstationary state with a precessing spin.

  16. First experimental results from 2MeV proton tandem accelerator for neutron productiona)

    NASA Astrophysics Data System (ADS)

    Kudryavtsev, A.; Belchenko, Yu.; Burdakov, A.; Davydenko, V.; Ivanov, A.; Khilchenko, A.; Konstantinov, S.; Krivenko, A.; Kuznetsov, A.; Mekler, K.; Sanin, A.; Shirokov, V.; Sorokin, I.; Sulyaev, Yu.; Tiunov, M.

    2008-02-01

    A 2MeV proton tandem accelerator with vacuum insulation was developed and first experiments are carried out in the Budker Institute of Nuclear Physics (Novosibirsk). The accelerator is designed for neutron production via reaction Li7(p,n)Be7 for the boron neutron-capture therapy of the brain tumors, and for explosive detection based on 9.1724MeV resonance gamma, which are produced via reaction C13(p,γ)N14, absorption in nitrogen.

  17. Dosimetry and fast neutron energies characterization of photoneutrons produced in some medical linear accelerators

    NASA Astrophysics Data System (ADS)

    Khaled, N. E.; Attalla, E. M.; Ammar, H.; Khalil, W.

    2011-12-01

    This work focusses on the estimation of induced photoneutrons energy, fluence, and strength using nuclear track detector (NTD) (CR-39). Photoneutron energy was estimated for three different linear accelerators, LINACs as an example for the commonly used accelerators. For high-energy linear accelerators, neutrons are produced as a consequence of photonuclear reactions in the target nuclei, accelerator head, field-flattening filters and beam collimators, and other irradiated objects. NTD (CR-39) is used to evaluate energy and fluence of the fast neutron. Track length is used to estimate fast photoneutrons energy for linear accelerators (Elekta 10 MV, Elekta 15 MV, and Varian 15 MV). Results show that the estimated neutron energies for the three chosen examples of LINACs reveals neutron energies in the range of 1-2 MeV for 10 and 15 MV X-ray beams. The fluence of neutrons at the isocenter (Φtotal) is found to be (4×106 n cm2 Gy-1) for Elekta machine 10 MV. The neutron source strengths Q are calculated. It was found to be 0.2×1012 n Gy-1 X-ray at the isocenter. This work represents simple, low cost, and accurate methods of measuring fast neutrons dose and energies.

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

    NASA Astrophysics Data System (ADS)

    Agosteo, S.; Curzio, G.; d'Errico, F.; Nath, R.; Tinti, R.

    2002-01-01

    Neutron capture in 10B produces energetic alpha particles that have a high linear energy transfer in tissue. This results in higher cell killing and a higher relative biological effectiveness compared to photons. Using suitably designed boron compounds which preferentially localize in cancerous cells instead of healthy tissues, boron neutron capture therapy (BNCT) has the potential of providing a higher tumor cure rate within minimal toxicity to normal tissues. This clinical approach requires a thermal neutron source, generally a nuclear reactor, with a fluence rate sufficient to deliver tumorcidal doses within a reasonable treatment time (minutes). Thermal neutrons do not penetrate deeply in tissue, therefore BNCT is limited to lesions which are either superficial or otherwise accessible. In this work, we investigate the feasibility of an accelerator-based thermal neutron source for the BNCT of skin melanomas. The source was designed via MCNP Monte Carlo simulations of the thermalization of a fast neutron beam, generated by 7 MeV deuterons impinging on a thick target of beryllium. The neutron field was characterized at several deuteron energies (3.0-6.5 MeV) in an experimental structure installed at the Van De Graaff accelerator of the Laboratori Nazionali di Legnaro, in Italy. Thermal and epithermal neutron fluences were measured with activation techniques and fast neutron spectra were determined with superheated drop detectors (SDD). These neutron spectrometry and dosimetry studies indicated that the fast neutron dose is unacceptably high in the current design. Modifications to the current design to overcome this problem are presented.

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

    SciTech Connect

    Mitchell, H.E.

    1996-04-01

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

  20. A measurement of actinide neutron transmutations with accelerator mass spectrometry in order to infer neutron capture cross sections

    NASA Astrophysics Data System (ADS)

    Bauder, William K.

    Improved neutron capture cross section data for transuranic and minor actinides are essential for assessing possibilities for next generation reactors and advanced fuel cycles. The Measurement of Actinide Neutron TRAnsmutation (MANTRA) project aims to make a comprehensive set of energy integrated neutron capture cross section measurements for all relevant isotopes from Th to Cf. The ability to extract these cross sections relies on the use of Accelerator Mass Spectrometry (AMS) to analyze isotopic concentrations in samples irradiated in the Advanced Test Reactor (ATR). The AMS measurements were performed at the Argonne Tandem Linear Accelerator System (ATLAS) and required a number of key technical developments to the ion source, accelerator, and detector setup. In particular, a laser ablation material injection system was developed at the electron cyclotron resonance ion source. This system provides a more effective method to produce ion beams from samples containing only 1% actinide material and offers some benefits for reducing cross talk in the source. A series of four actinide measurements are described in this dissertation. These measurements represent the most substantial AMS work attempted at ATLAS and the first results of the MANTRA project. Isotopic ratios for one and two neutron captures were measured in each sample with total uncertainties around 10%. These results can be combined with a MCNP model for the neutron fluence to infer actinide neutron capture cross sections.

  1. Target design optimization for an electron accelerator driven subcritical facility with circular and square beam profiles.

    SciTech Connect

    Gohar, M. Y. A; Sofu, T.; Zhong, Z.; Belch, H.; Naberezhnev, D.; Nuclear Engineering Division

    2008-10-30

    A subcritical facility driven by an electron accelerator is planned at the Kharkov Institute of Physics and Technology (KIPT) in Ukraine for medical isotope production, materials research, training, and education. The conceptual design of the facility is being pursued through collaborations between ANL and KIPT. As part of the design effort, the high-fidelity analyses of various target options are performed with formulations to reflect the realistic configuration and the three dimensional geometry of each design. This report summarizes the results of target design optimization studies for electron beams with two different beam profiles. The target design optimization is performed via the sequential neutronic, thermal-hydraulic, and structural analyses for a comprehensive assessment of each configuration. First, a target CAD model is developed with proper emphasis on manufacturability to provide a basis for separate but consistent models for subsequent neutronic, thermal-hydraulic, and structural analyses. The optimizations are pursued for maximizing the neutron yield, streamlining the flow field to avoid hotspots, and minimizing the thermal stresses to increase the durability. In addition to general geometric modifications, the inlet/outlet channel configurations, target plate partitioning schemes, flow manipulations and rates, electron beam diameter/width options, and cladding material choices are included in the design optimizations. The electron beam interactions with the target assembly and the neutronic response of the subcritical facility are evaluated using the MCNPX code. the results for the electron beam energy deposition, neutron generation, and utilization in the subcritical pile are then used to characterize the axisymmetric heat generation profiles in the target assembly with explicit simulations of the beam tube, the coolant, the clad, and the target materials. Both tungsten and uranium are considered as target materials. Neutron spectra from tungsten

  2. Stability study for matching in laser driven plasma acceleration

    NASA Astrophysics Data System (ADS)

    Rossi, A. R.; Anania, M. P.; Bacci, A.; Belleveglia, M.; Bisesto, F. G.; Chiadroni, E.; Cianchi, A.; Curcio, A.; Gallo, A.; Di Giovenale, D.; Di Pirro, G.; Ferrario, M.; Marocchino, A.; Massimo, F.; Mostacci, A.; Petrarca, M.; Pompili, R.; Serafini, L.; Tomassini, P.; Vaccarezza, C.; Villa, F.

    2016-09-01

    In a recent paper [14], a scheme for inserting and extracting high brightness electron beams to/from a plasma based acceleration stage was presented and proved to be effective with an ideal bi-Gaussian beam, as could be delivered by a conventional photo-injector. In this paper, we extend that study, assessing the method stability against some jitters in the properties of the injected beam. We find that the effects of jitters in Twiss parameters are not symmetric in results; we find a promising configuration that yields better performances than the setting proposed in [14]. Moreover we show and interpret what happens when the beam charge profiles are modified.

  3. A "slingshot" laser-driven acceleration mechanism of plasma electrons

    NASA Astrophysics Data System (ADS)

    Fiore, Gaetano; De Nicola, Sergio

    2016-09-01

    We briefly report on the recently proposed Fiore et al. [1] and Fiore and De Nicola [2] electron acceleration mechanism named "slingshot effect": under suitable conditions the impact of an ultra-short and ultra-intense laser pulse against the surface of a low-density plasma is expected to cause the expulsion of a bunch of superficial electrons with high energy in the direction opposite to that of the pulse propagation; this is due to the interplay of the huge ponderomotive force, huge longitudinal field arising from charge separation, and the finite size of the laser spot.

  4. The safe and economical operations of a reactor driven by a small proton accelerator

    SciTech Connect

    Takahashi, Hiroshi; Takashita, Hirofumi

    1994-06-01

    An accelerator can be used to increase the safety and neutron economy of a power reactor and transmuter of long-lived radioactive wastes, such as minor actinides and fission products, by providing neutrons for its subcritical operation. Instead of the rather large subcriticality of k=0.9-0.95 which we originally proposed for such a transmutor, we propose to use a slightly subcritical reactor, such as k=0.99, which will avoid many of the technical difficulties that are associated with large subcriticality, such as localized power peaking, radiation damage due to the injection of medium-energy protons, the high current accelerator, and the requirement for a long beam-expansion section. We analyzed the radiation damage of the target area, and discuss the necessity of high neutron economy to transmute the long lived fission products using the fast reactor system.

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

    PubMed

    LaRiviere, P D

    1985-01-01

    During the assembly of the prototype Clinac 2500, a unique opportunity arose to measure the cumulative total neutron yield of the machine as the major subassemblies were added, section by section. Differentiation of the results led to an inventory of the relative strength of the several neutron sources identified. The method utilized the fact that the scattered neutron fluence in a cavity in concrete is nearly uniform throughout the space and proportional to the fast neutron source strength. When normalized to the neutron output of the guide with bend magnet vacuum chamber, the relative neutron source strengths found were target, 1.9; primary collimator, 2.4; steel filter, 0.6; tungsten filter, 1.5; and jaw system, 0.8 open and approximately 2.0 closed. There is reasonable agreement between these measurements and published estimates of the yields from the major components of the treatment head. PMID:4079876

  6. Summary Report of Working Group 5: Electron Beam Driven Plasma Accelerators

    SciTech Connect

    Hogan, Mark J.; Conde, Manoel E.

    2009-01-22

    Electron beam driven plasma accelerators have seen rapid progress over the last decade. Recent efforts have built on this success by constructing a concept for a plasma wakefield accelerator based linear collider. The needs for any future collider to deliver both energy and luminosity have substantial implications for interpreting current experiments and setting priorities for the future. This working group reviewed current experiments and ideas in the context of the demands of a future collider. The many discussions and presentations are summarized here.

  7. Development of a coupled dynamics code with transport theory capability and application to accelerator driven systems transients

    SciTech Connect

    Cahalan, J. E.; Ama, T.; Palmiotti, G.; Taiwo, T. A.; Yang, W. S.

    2000-03-09

    The VARIANT-K and DIF3D-K nodal spatial kinetics computer codes have been coupled to the SAS4A and SASSYS-1 liquid metal reactor accident and systems analysis codes. SAS4A and SASSYS-1 have been extended with the addition of heavy liquid metal (Pb and Pb-Bi) thermophysical properties, heat transfer correlations, and fluid dynamics correlations. The coupling methodology and heavy liquid metal modeling additions are described. The new computer code suite has been applied to analysis of neutron source and thermal-hydraulics transients in a model of an accelerator-driven minor actinide burner design proposed in an OECD/NEA/NSC benchmark specification. Modeling assumptions and input data generation procedures are described. Results of transient analyses are reported, with emphasis on comparison of P1 and P3 variational nodal transport theory results with nodal diffusion theory results, and on significance of spatial kinetics effects.

  8. The Need for a Neutron Source at the Rare Isotope Accelerator

    SciTech Connect

    Ahle, L E; Rusnak, B; Roberts, K E; Roeben, M D; Hausmann, M; Reifarth, R; Vieira, D

    2005-05-13

    An intense neutron source facility with radiochemical processing capability is necessary at the Rare Isotope Accelerator to fully realize its potential benefit to stockpile stewardship and astrophysics. While many of the important physics missions of RIA can be addressed with radioactive ion beams, direct neutron cross-section measurements of interest to stockpile stewardship and astrophysics cannot because one cannot make a neutron target. Thus, one must collect a sufficient amount of the appropriate short-lived isotope, quickly chemically process the material into a target, and promptly radiate the sample with an intense ''beam'' of neutrons. The unprecedented production rates expected at RIA enables many of these direct neutron cross-section measurements, but only if the proper infrastructure is in place. This document not only describes the major piece of this required infrastructure, a neutron source facility with radiochemical processing capabilities, but also the motivation for measuring such direct neutron cross-sections.

  9. On the Performance of Point Kinetics for the Analysis of Accelerator-Driven Systems

    SciTech Connect

    Eriksson, M.; Cahalan, J.E.; Yang, W.S.

    2005-03-15

    The ability of point kinetics to describe dynamic processes in accelerator-driven systems (ADSs) is investigated. Full three-dimensional energy-space-time-dependent calculations, coupled with thermal and hydraulic feedback effects, are performed and used as a standard of comparison. Various transient accident sequences are studied. Calculations are performed in the range of k{sub eff} = 0.9594 to 0.9987 to provide insight into the dependence of the performance on the subcritical level. Numerical experiments are carried out on a minor-actinide-loaded and lead-bismuth-cooled ADS. It is shown that the point kinetics approximation is capable of providing highly accurate calculations in such systems. The results suggest better precision at lower k{sub eff} levels. It is found that subcritical operation provides features that are favorable from a point kinetics view of application. For example, reduced sensitivity to system reactivity perturbations effectively mitigates any spatial distortions. If a subcritical reactor is subject to a change in the strength of the external source, or a change in reactivity within the subcritical range, the neutron population will adjust to a new stationary level. Therefore, within the normal range of operation, the power predicted by the point kinetics method and the associated error in comparison with the exact solution tends to approach an essentially bounded value. It was found that the point kinetics model is likely to underestimate the power rise following a positive reactivity insertion in an ADS, which is similar to the behavior in critical systems. However, the effect is characteristically lowered in subcritical versus critical or near-critical reactor operation.

  10. Dogs lap using acceleration-driven open pumping

    PubMed Central

    Gart, Sean; Socha, John J.; Vlachos, Pavlos P.; Jung, Sunghwan

    2015-01-01

    Dogs lap because they have incomplete cheeks and cannot suck. When lapping, a dog’s tongue pulls a liquid column from the bath, suggesting that the hydrodynamics of column formation are critical to understanding how dogs drink. We measured lapping in 19 dogs and used the results to generate a physical model of the tongue’s interaction with the air–fluid interface. These experiments help to explain how dogs exploit the fluid dynamics of the generated column. The results demonstrate that effects of acceleration govern lapping frequency, which suggests that dogs curl the tongue to create a larger liquid column. Comparing lapping in dogs and cats reveals that, despite similar morphology, these carnivores lap in different physical regimes: an unsteady inertial regime for dogs and steady inertial regime for cats. PMID:26668382

  11. Dogs lap using acceleration-driven open pumping.

    PubMed

    Gart, Sean; Socha, John J; Vlachos, Pavlos P; Jung, Sunghwan

    2015-12-29

    Dogs lap because they have incomplete cheeks and cannot suck. When lapping, a dog's tongue pulls a liquid column from the bath, suggesting that the hydrodynamics of column formation are critical to understanding how dogs drink. We measured lapping in 19 dogs and used the results to generate a physical model of the tongue's interaction with the air-fluid interface. These experiments help to explain how dogs exploit the fluid dynamics of the generated column. The results demonstrate that effects of acceleration govern lapping frequency, which suggests that dogs curl the tongue to create a larger liquid column. Comparing lapping in dogs and cats reveals that, despite similar morphology, these carnivores lap in different physical regimes: an unsteady inertial regime for dogs and steady inertial regime for cats. PMID:26668382

  12. Simulator for an Accelerator-Driven Subcritical Fissile Solution System

    SciTech Connect

    Klein, Steven Karl; Day, Christy M.; Determan, John C.

    2015-09-14

    LANL has developed a process to generate a progressive family of system models for a fissile solution system. This family includes a dynamic system simulation comprised of coupled nonlinear differential equations describing the time evolution of the system. Neutron kinetics, radiolytic gas generation and transport, and core thermal hydraulics are included in the DSS. Extensions to explicit operation of cooling loops and radiolytic gas handling are embedded in these systems as is a stability model. The DSS may then be converted to an implementation in Visual Studio to provide a design team the ability to rapidly estimate system performance impacts from a variety of design decisions. This provides a method to assist in optimization of the system design. Once design has been generated in some detail the C++ version of the system model may then be implemented in a LabVIEW user interface to evaluate operator controls and instrumentation and operator recognition and response to off-normal events. Taken as a set of system models the DSS, Visual Studio, and LabVIEW progression provides a comprehensive set of design support tools.

  13. Accelerator-based Neutron Fluence Standard of the National Metrology Institute of Japan

    NASA Astrophysics Data System (ADS)

    Harano, Hideki; Matsumoto, Tetsuro; Nishiyama, Jun; Uritani, Akira; Kudo, Katsuhisa

    2009-03-01

    We report the present status of the national standard on accelerator-based fast neutron fluences in Japan. Monoenergetic neutron fluence standards have been established at 144 keV, 565 keV, 5.0 MeV and 8.0 MeV by using a Van de Graaff accelerator and at 2.5 MeV and 14.8 MeV by using a Cockcroft Walton accelerator. These standards are prepared to measure the detection efficiency and the energy response of neutron sensitive devices, such as personal dosimeters and survey meters. Neutron production and absolute fluence measurement for these energies are described. We are developing a new standard in the energy region of a few tens of keV, which is also introduced here as well as our future plans.

  14. Neutron-proton-converter acceleration mechanism at subphotospheres of relativistic outflows.

    PubMed

    Kashiyama, Kazumi; Murase, Kohta; Mészáros, Peter

    2013-09-27

    We study a type of particle acceleration that operates via neutron-proton conversion in inelastic nuclear collisions. This mechanism can be expected for relativistic shocks at subphotospheres if relativistic outflows contain neutrons. Using a test-particle approximation, we numerically calculate the energy spectrum and the efficiency of accelerated particles, and show that a good energy fraction of the nucleons can be accelerated. This mechanism may be especially relevant if the shock is radiation mediated, and it would enhance the detectability of GeV-TeV neutrinos. PMID:24116765

  15. Electron heating in radiation-pressure-driven proton acceleration with a circularly polarized laser

    NASA Astrophysics Data System (ADS)

    Paradkar, B. S.; Krishnagopal, S.

    2016-02-01

    Dynamics of electron heating in the radiation-pressure-driven acceleration through self-induced transparency (SIT) is investigated with the help of particle-in-cell simulations. The SIT is achieved through laser filamentation which is seeded by the transverse density modulations due to the Rayleigh-Taylor-like instability. We observe stronger SIT induced electron heating for the longer duration laser pulses leading to deterioration of accelerated ion beam quality (mainly energy spread). Such heating can be controlled to obtain a quasimonoenergetic beam by cascaded foils targets where a second foil behind the main accelerating foil acts as a laser reflector to suppress the SIT.

  16. Neutronics analysis of deuterium-tritium-driven experimental hybrid blankets

    SciTech Connect

    Sahin, S.; Kumar, A.

    1984-07-01

    At the Swiss Federal Institute of Technology, an experimental fusion and fusion-fission (hybrid) reactor facility is near completion. Experiments are scheduled to begin in February 1984. The experimental cavity leads one to plan experiments mostly with blankets in plane geometry. Five different hybrid blanket modules in plane geometry are analyzed with two different left boundary conditions representing varying experimental situations. Numbers I and II represent energy and fissile fuel producing blankets, whereas number III is mainly a fissile fuel producing blanket. Numbers IV and V are actinide burning blankets. It is shown that the overall neutronic performance, such as k /sub eff/ , energy multiplication factor M, fusile and fissile breeding, of a hybrid blanket with transplutonium actinide fuel is already better than that of a UO/sub 2/ or ThO/sub 2/ hybrid blanket. Furthermore, the transplutonium actinide waste is partly converted into precious nuclear fuel of a new type, such as /sup 242m/ Am and /sup 245/Cm. An experimental blanket with a vacuum left boundary has a harder neutron spectrum, and also excessive neutron leakage from the front surface and the lateral surfaces, as compared to that in the blanket in confinement geometry. It leads to the poorer neutronic performance of the former.

  17. Propagation characteristics of neutrons leaking from the accelerator facilities.

    PubMed

    Kitaichi, Masatoshi; Sawamura, Sadashi; Wakisaka, Masashi; Kaneko, Junichi H; Ochiai, Kentaro; Nishitani, Takeo; Sawamura, Teruko

    2004-01-01

    In this study spatial and time distribution of neutrons leaking from Hokkaido University 45 MeV Electron Linac facility have measured and compared with the Monte Carlo simulations. The neutron transport processes inside and outside the facility building has been simulated using MCNP. The neutrons have measured by BF3 counters and 3He counters with polyethylene moderators up to the distance of 330 m from the facility. The spatial distribution of ambient dose equivalent converted from the counts has been compared with the simulation. The distribution estimated from the counts by the BF3 counter has been shown fairly good agreement with the calculation. The spatial distribution of counts obtained at the 45 MeV Electron Linac facility has been compared with that obtained at the Fusion Neutronics Source (FNS) facility of JAERI. The difference between the propagation characteristics of neutrons leaking from those facilities has been discussed. PMID:15353739

  18. Using a Tandem Pelletron accelerator to produce a thermal neutron beam for detector testing purposes.

    PubMed

    Irazola, L; Praena, J; Fernández, B; Macías, M; Bedogni, R; Terrón, J A; Sánchez-Nieto, B; Arias de Saavedra, F; Porras, I; Sánchez-Doblado, F

    2016-01-01

    Active thermal neutron detectors are used in a wide range of measuring devices in medicine, industry and research. For many applications, the long-term stability of these devices is crucial, so that very well controlled neutron fields are needed to perform calibrations and repeatability tests. A way to achieve such reference neutron fields, relying on a 3 MV Tandem Pelletron accelerator available at the CNA (Seville, Spain), is reported here. This paper shows thermal neutron field production and reproducibility characteristics over few days. PMID:26595777

  19. Particle acceleration on a chip: A laser-driven micro-accelerator for research and industry

    NASA Astrophysics Data System (ADS)

    Yoder, R. B.; Travish, G.

    2013-03-01

    Particle accelerators are conventionally built from radio-frequency metal cavities, but this technology limits the maximum energy available and prevents miniaturization. In the past decade, laser-powered acceleration has been intensively studied as an alternative technology promising much higher accelerating fields in a smaller footprint and taking advantage of recent advances in photonics. Among the more promising approaches are those based on dielectric field-shaping structures. These ``dielectric laser accelerators'' (DLAs) scale with the laser wavelength employed and can be many orders of magnitude smaller than conventional accelerators; DLAs may enable the production of high-intensity, ultra-short relativistic electron bunches in a chip-scale device. When combined with a high- Z target or an optical-period undulator, these systems could produce high-brilliance x-rays from a breadbox-sized device having multiple applications in imaging, medicine, and homeland security. In our research program we have developed one such DLA, the Micro-Accelerator Platform (MAP). We describe the fundamental physics, our fabrication and testing program, and experimental results to date, along with future prospects for MAP-based light-sources and some remaining challenges. Supported in part by the Defense Threat Reduction Agency and National Nuclear Security Administration.

  20. Particle trapping and beam transport issues in laser driven accelerators

    NASA Astrophysics Data System (ADS)

    Gwenael, Fubiani; Wim, Leemans; Eric, Esarey

    2000-10-01

    The LWFA and colliding pulses [1][2] sheme are capable of producing very compact electron bunches where the longitudinal size is much smaller than the transverse size. In this case, even if the electrons are relativistic, space charge force can affect the longitudinal and transverse bunch properties [3][4]. In the Self-modulated regime and the colliding pulse sheme, electrons are trapped from the background plasma and rapidly accelerated. We present theoretical studies of the generation and transport of electron bunches in LWFAs. The space charge effect induced in the bunch is modelled assuming the bunch is ellipsoid like. Beam transport in vacuum, comparison between gaussian and waterbag distribution, comparison between envelope model and PIC simulation will be discussed. This work is supported by the Director, Office of Science, Office of High Energy & Nuclear Physics, High Energy Physics Division, of the U.S Department of Energy, under Contract No. DE-AC03-76SF00098 [1]E.Esarey et al.,IEEE Trans. Plasma Sci. PS-24,252 (1996); W.P. Leemans et al, ibidem, 331. [2]D. Umstadter et al., Phys. Rev. Lett. 76, 2073 (1996); E.Esarey et al., Phys. Rev. Lett. 79, 2682 (1997); C.B Schroeder et al., Phys. Rev. E59, 6037 (1999) [3]DESY M87-161 (1987); DESY M88-013 (1988) [4] R.W. Garnett and T.P Wangler, IEEE Part. Acce. Conf. (1991)

  1. Important requirements for RF generators for Accelerator-Driven Transmutation Technologies (ADTT)

    SciTech Connect

    Lynch, M.T.; Tallerico, P.J.; Lawrence, G.P.

    1994-09-01

    All Accelerator-Driven Transmutation applications require very large amounts of RF Power. For example, one version of a Plutonium burning system requires an 800-MeV, 80-mA, proton accelerator running at 100% duty factor. This accelerator requires approximately 110-MW of continuous RF power if one assumes only 10% reserve power for control of the accelerator fields. In fact, to minimize beam spill, the RF controls may need as much as 15 to 20% of reserve power. In addition, unlike an electron accelerator in which the beam is relativistic, a failed RF station can disturb the synchronism of the beam, possibly shutting down the entire accelerator. These issues and more lead to a set of requirements for the RF generators which are stringent, and in some cases, conflicting. In this paper, we will describe the issues and requirements, and outline a plan for RF generator development to meet the needs of the Accelerator-Driven Transmutation Technologies. The key issues which will be discussed include: operating efficiency, operating linearity, effect on the input power grid, bandwidth, gain, reliability, operating voltage, and operating current.

  2. Impulse Characteristics of Laser-driven In-Tube Accelerator (LITA)

    SciTech Connect

    Ohtani, Toshiro; Mori, Koichi; Sasoh, Akihiro

    2006-05-02

    In this study, impulse generation processes induced by a single laser pulse in the laser-driven in-tube accelerator are studied through pressure history measured at the center of the projectile base, which acts also as a parabolic mirror. The effects of the fill pressure, laser energy and length of a shroud are analyzed.

  3. Impulse Characteristics of Laser-driven In-Tube Accelerator (LITA)

    NASA Astrophysics Data System (ADS)

    Ohtani, Toshiro; Mori, Koichi; Sasoh, Akihiro

    2006-05-01

    In this study, impulse generation processes induced by a single laser pulse in the laser-driven in-tube accelerator are studied through pressure history measured at the center of the projectile base, which acts also as a parabolic mirror. The effects of the fill pressure, laser energy and length of a shroud are analyzed.

  4. NIFTI and DISCOS: New concepts for a compact accelerator neutron source for boron neutron capture therapy applications

    SciTech Connect

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

    1995-06-01

    Two new concepts, NIFTI and DISCOS, are described. These concepts enable the efficient production of epithermal neutrons for BNCT (Boron Neutron Capture Therapy) medical treatment, utilizing a low current, low energy proton beam impacting on a lithium target. The NIFTI concept uses fluoride compounds, such as lead or beryllium fluoride, to efficiently degrade high energy neutrons from the lithium target to the lower energies required for BNCT. The fluoride compounds are in turn encased in an iron layer that strongly impedes the transmission of neutrons with energies above 24 KeV. Lower energy neutrons readily pass through this iron filter, which has a deep window in its scattering cross section at 24 KeV. The DISCOS concept uses a rapidly rotating, high g disc to create a series of thin ({approximately} 1 micron thickness) liquid lithium targets in the form of continuous films or sheets of discrete droplets--through which the proton beam passes. The average energy lost by a proton as it passes through a single target is small, approximately 10 KeV. Between the targets, the proton beam is re-accelerated by an applied DC electric field. The DISCOS approach enables the accelerator--target facility to operate with a beam energy only slightly above the threshold value for neutron production--resulting in an output beam of low-energy epithermal neutrons--while achieving a high yield of neutrons per milliamp of proton beam current. Parametric trade studies of the NIFTI and DISCOS concepts are described. These include analyses of a broad range of NIFTI designs using the Monte carlo MCNP neutronics code, as well as mechanical and thermal-hydraulic analyses of various DISCOS designs.

  5. Numerical study of neutron beam divergence in a beam-fusion scenario employing laser driven ions

    NASA Astrophysics Data System (ADS)

    Alejo, A.; Green, A.; Ahmed, H.; Robinson, A. P. L.; Cerchez, M.; Clarke, R.; Doria, D.; Dorkings, S.; Fernandez, J.; McKenna, P.; Mirfayzi, S. R.; Naughton, K.; Neely, D.; Norreys, P.; Peth, C.; Powell, H.; Ruiz, J. A.; Swain, J.; Willi, O.; Borghesi, M.; Kar, S.

    2016-09-01

    The most established route to create a laser-based neutron source is by employing laser accelerated, low atomic-number ions in fusion reactions. In addition to the high reaction cross-sections at moderate energies of the projectile ions, the anisotropy in neutron emission is another important feature of beam-fusion reactions. Using a simple numerical model based on neutron generation in a pitcher-catcher scenario, anisotropy in neutron emission was studied for the deuterium-deuterium fusion reaction. Simulation results are consistent with the narrow-divergence (∼ 70 ° full width at half maximum) neutron beam recently served in an experiment employing multi-MeV deuteron beams of narrow divergence (up to 30° FWHM, depending on the ion energy) accelerated by a sub-petawatt laser pulse from thin deuterated plastic foils via the Target Normal Sheath Acceleration mechanism. By varying the input ion beam parameters, simulations show that a further improvement in the neutron beam directionality (i.e. reduction in the beam divergence) can be obtained by increasing the projectile ion beam temperature and cut-off energy, as expected from interactions employing higher power lasers at upcoming facilities.

  6. Spectral Features in Laser Driven Proton Acceleration from Cylindrical Solid-density Hydrogen Jets

    NASA Astrophysics Data System (ADS)

    Curry, Chandra; Gauthier, Maxence; Mishra, Rohini; Kim, Jongjin; Goede, Sebastian; Propp, Adrienne; Fiuza, Frederico; Glenzer, Siegfried H.; Williams, Jackson; Ruby, John; Goyon, Clement; Pak, Art E.; Kerr, Shaun; Tsui, Ying Y.; Ramakrishna, Bhuvanesh; Aurand, Bastian; Willi, Oswald; Roedel, Christian

    2015-11-01

    The generation of monoenergetic proton beams by ultrashort high-intensity laser-plasma interactions is of great interest for applications such as stopping power measurements, fast ignition laser confinement fusion, and ion beam therapy. In general, the commonly used mechanism of target normal sheath acceleration (TNSA) does not provide the required energy spread or maximum proton energy. Here we study alternative acceleration mechanisms, which have been identified in particle in cell (PIC) simulations, to overcome the limitations of TNSA. Using the Titan laser system at the Lawrence Livermore National Laboratory, we investigate proton acceleration from wire targets and a cryogenic solid-density hydrogen jet. Due to the cylindrical geometry, TNSA is suppressed allowing other accelerations mechanisms to become observable. Quasi-monoenergetic features in laser-forward direction are observed in the proton spectrum indicating radiation-pressure-driven acceleration mechanisms. Our experimental results are accompanied by supporting PIC simulations.

  7. A role of accelerator-driven reactor to meet future energy demands

    SciTech Connect

    Takahashi, H.; An, Y.; Yang, Y.; Zhao, Y.; Tsoupas, N.

    1998-03-01

    Fissile fuel can be produced at a high rate using an accelerator driven Pu fueled fast reactor operated at deep subcriticality; this approach avoids encountering a shortage of Pu during a high rate of growth in the production of nuclear energy. Slightly reducing the acceleration field minimizes the tripping of the beam and the radiation dose from the accelerator; hence the accelerator can be operated as a highly reliable industrial machine. The usefulness of a windowless liquid jet target, which eliminates the spreading of the beam and problems of radiation damage is emphasized, in association with the small size of the target. The requirements for a proton beam accelerator for this system are discussed.

  8. Preferential enhancement of laser-driven carbon ion acceleration from optimized nanostructured surfaces

    NASA Astrophysics Data System (ADS)

    Dalui, Malay; Wang, W.-M.; Trivikram, T. Madhu; Sarkar, Subhrangshu; Tata, Sheroy; Jha, J.; Ayyub, P.; Sheng, Z. M.; Krishnamurthy, M.

    2015-07-01

    High-intensity ultrashort laser pulses focused on metal targets readily generate hot dense plasmas which accelerate ions efficiently and can pave way to compact table-top accelerators. Laser-driven ion acceleration studies predominantly focus on protons, which experience the maximum acceleration owing to their highest charge-to-mass ratio. The possibility of tailoring such schemes for the preferential acceleration of a particular ion species is very much desired but has hardly been explored. Here, we present an experimental demonstration of how the nanostructuring of a copper target can be optimized for enhanced carbon ion acceleration over protons or Cu-ions. Specifically, a thin (≈0.25 μm) layer of 25-30 nm diameter Cu nanoparticles, sputter-deposited on a polished Cu-substrate, enhances the carbon ion energy by about 10-fold at a laser intensity of 1.2×1018  W/cm2. However, particles smaller than 20 nm have an adverse effect on the ion acceleration. Particle-in-cell simulations provide definite pointers regarding the size of nanoparticles necessary for maximizing the ion acceleration. The inherent contrast of the laser pulse is found to play an important role in the species selective ion acceleration.

  9. Preferential enhancement of laser-driven carbon ion acceleration from optimized nanostructured surfaces.

    PubMed

    Dalui, Malay; Wang, W-M; Trivikram, T Madhu; Sarkar, Subhrangsu; Sarkar, Subhrangshu; Tata, Sheroy; Jha, J; Ayyub, P; Sheng, Z M; Krishnamurthy, M

    2015-01-01

    High-intensity ultrashort laser pulses focused on metal targets readily generate hot dense plasmas which accelerate ions efficiently and can pave way to compact table-top accelerators. Laser-driven ion acceleration studies predominantly focus on protons, which experience the maximum acceleration owing to their highest charge-to-mass ratio. The possibility of tailoring such schemes for the preferential acceleration of a particular ion species is very much desired but has hardly been explored. Here, we present an experimental demonstration of how the nanostructuring of a copper target can be optimized for enhanced carbon ion acceleration over protons or Cu-ions. Specifically, a thin (≈ 0.25 μm) layer of 25-30 nm diameter Cu nanoparticles, sputter-deposited on a polished Cu-substrate, enhances the carbon ion energy by about 10-fold at a laser intensity of 1.2 × 10(18)  W/cm(2). However, particles smaller than 20 nm have an adverse effect on the ion acceleration. Particle-in-cell simulations provide definite pointers regarding the size of nanoparticles necessary for maximizing the ion acceleration. The inherent contrast of the laser pulse is found to play an important role in the species selective ion acceleration. PMID:26153048

  10. Preferential enhancement of laser-driven carbon ion acceleration from optimized nanostructured surfaces

    PubMed Central

    Dalui, Malay; Wang, W.-M.; Trivikram, T. Madhu; Sarkar, Subhrangshu; Tata, Sheroy; Jha, J.; Ayyub, P.; Sheng, Z. M.; Krishnamurthy, M.

    2015-01-01

    High-intensity ultrashort laser pulses focused on metal targets readily generate hot dense plasmas which accelerate ions efficiently and can pave way to compact table-top accelerators. Laser-driven ion acceleration studies predominantly focus on protons, which experience the maximum acceleration owing to their highest charge-to-mass ratio. The possibility of tailoring such schemes for the preferential acceleration of a particular ion species is very much desired but has hardly been explored. Here, we present an experimental demonstration of how the nanostructuring of a copper target can be optimized for enhanced carbon ion acceleration over protons or Cu-ions. Specifically, a thin (≈0.25 μm) layer of 25–30 nm diameter Cu nanoparticles, sputter-deposited on a polished Cu-substrate, enhances the carbon ion energy by about 10-fold at a laser intensity of 1.2×1018  W/cm2. However, particles smaller than 20 nm have an adverse effect on the ion acceleration. Particle-in-cell simulations provide definite pointers regarding the size of nanoparticles necessary for maximizing the ion acceleration. The inherent contrast of the laser pulse is found to play an important role in the species selective ion acceleration. PMID:26153048

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

    SciTech Connect

    He, Min-Qing Zhang, Hua; Wu, Si-Zhong; Wu, Jun-Feng; Chen, Mo; Cai, Hong-Bo Zhou, Cang-Tao; Cao, Li-Hua; Zheng, Chun-Yang; Zhu, Shao-Ping; He, X. T.; Dong, Quan-Li; Sheng, Zheng-Ming; Pei, Wen-Bing

    2015-12-15

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

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

    NASA Astrophysics Data System (ADS)

    He, Min-Qing; Cai, Hong-Bo; Zhang, Hua; Dong, Quan-Li; Zhou, Cang-Tao; Wu, Si-Zhong; Sheng, Zheng-Ming; Cao, Li-Hua; Zheng, Chun-Yang; Wu, Jun-Feng; Chen, Mo; Pei, Wen-Bing; Zhu, Shao-Ping; He, X. T.

    2015-12-01

    A scheme for neutron production is investigated in which an ultra-intense laser is irradiated into a two-layer (deuterium and aurum) spherical shell target through the cone shaped entrance hole. It is found that the energy conversion efficiency from laser to target can reach as high as 71%, and deuterium ions are heated to a maximum energy of several MeV from the inner layer surface. These ions are accelerated towards the center of the cavity and accumulated finally with a high density up to tens of critical density in several picoseconds. Two different mechanisms account for the efficient yield of the neutrons in the cavity: (1) At the early stage, the neutrons are generated by the high energy deuterium ions based on the "beam-target" approach. (2) At the later stage, the neutrons are generated by the thermonuclear fusion when the most of the deuterium ions reach equilibrium in the cavity. It is also found that a large number of deuterium ions accelerated inward can pass through the target center and the outer Au layer and finally stopped in the CD2 layer. This also causes efficient yield of neutrons inside the CD2 layer due to "beam-target" approach. A postprocessor has been designed to evaluate the neutron yield and the neutron spectrum is obtained.

  13. Nuclear modeling for applications in medical radiation therapy and accelerator-driven technologies

    SciTech Connect

    Chadwick, M.B.

    1995-06-01

    An understanding of the interactions of neutrons and protons below a few hundred MeV with nuclei is important for a number of applications. In this paper, two new applications are discussed: radiation transport calculations of energy deposition in fast neutron and proton cancer radiotherapy to optimize the dose given to a tumor; and intermediate-energy proton accelerators which are currently being designed for a range of applications including the destruction of long-lived radioactive nuclear waste. We describe nuclear theory calculations of direct, preequilibrium, and compound nucleus reaction mechanisms important for the modeling of these systems.

  14. (Deuterium-deuterium)-driven experimental hybrid blankets and their neutronic analyses

    SciTech Connect

    Kumar, A.; Sahin, S.

    1984-09-01

    The impressive progress made so far toward the achievement of the physics goal of ignited fusion fuel of deuterium-tritium (D-T) is stirring the scientific community to look back and work for the earliest possible introduction of advanced fusion fuel based reactors with the ultimate objective of very clean, safe, and limitless fusion power. As the introduction of advanced fuel fusion drivers is expected to be in phases due to energetics considerations, it is quite instructive to examine the neutronic aspects of deuterium-deuterium (D-D) neutron driven hybrid blankets. The neutronics investigations of some compact hybrid blankets that could be tested experimentally are presented. The blanket designs are selected to conform to a rather small experimental chamber of the LOTUS fusionfission hybrid facility. The parallelepiped-shaped blankets are driven by a (D-D) neutron source from one side. The fertile fuel is either ThO/sub 2/, natural UO/sub 2/, or LOTUS UO/sub 2/. The tritium breeders are chosen from lithium, LiAlO/sub 2/, or Li/sub 2/O. The relative performances of different fertile fuels and tritium breeders are compared. The performance characteristics of ThO/sub 2/ blankets driven by (D-T) and (D-D) neutrons are compared. The improvement in performance characteristics obtained by the introduction of actinides as multipliers with ThO/sub 2/ hybrid blankets is also investigated.

  15. Neutron field measurements for alara purposes around a Van de Graaff accelerator building.

    PubMed

    Kockerols, P; Lebacq, A L; Gasparro, J; Hult, M; Janssens, H; Lövestam, G; Vanhavere, F

    2004-01-01

    The Institute for Reference Materials and Measurements operates a 7.0 MV Van de Graaff accelerator to generate monoenergetic neutron radiation for experimental applications. Owing to increased intensities of generated neutron fields and the more stringent regulation related to the maximum dose for the public, a concrete shielding wall surrounding the experimental building was constructed. This paper presents a study aiming at evaluating the effect of the shielding on the neutron field outside the wall. For this purpose, the following measurements were carried out around the building: (1) cartography of the neutron field for different experimental conditions; (2) measurement of neutron spectra using multiple Bonner spheres; (3) activation measurements using gold discs followed by low-level gamma spectrometry. From the measurements, it can be concluded that the wall fulfils its purpose to reduce the neutron dose rate to the surrounding area to an acceptable level. PMID:15353736

  16. Klystron Modulator Design for the Los Alamos Neutron Science Center Accelerator

    SciTech Connect

    Reass, William A.; Baca, David M.; Partridge, Edward R.; Rees, Daniel E.

    2012-06-22

    This paper will describe the design of the 44 modulator systems that will be installed to upgrade the Los Alamos Neutron Science Center (LANSCE) accelerator RF system. The klystrons can operate up to 86 kV with a nominal 32 Amp beam current with a 120 Hz repetition rate and 15% duty cycle. The klystrons are a mod-anode design. The modulator is designed with analog feedback control to ensure the klystron beam current is flat-top regulated. To achieve fast switching while maintaining linear feedback control, a grid-clamp, totem-pole modulator configuration is used with an 'on' deck and an 'off' deck. The on and off deck modulators are of identical design and utilize a cascode connected planar triode, cathode driven with a high speed MOSFET. The derived feedback is connected to the planar triode grid to enable the flat-top control. Although modern design approaches suggest solid state designs may be considered, the planar triode (Eimac Y-847B) is very cost effective, is easy to integrate with the existing hardware, and provides a simplified linear feedback control mechanism. The design is very compact and fault tolerant. This paper will review the complete electrical design, operational performance, and system characterization as applied to the LANSCE installation.

  17. Neutron and gamma-ray signatures for particle acceleration in solar flares

    NASA Technical Reports Server (NTRS)

    Ramaty, R.; Murphy, R. J.

    1984-01-01

    The production of neutrons, 4 to 7 MeW nuclear gamma rays, positrons and pions resulting from the interaction of flare accelerated particles with the solar atmosphere was calculated. For the energy spectra of these particles the Bessel function predicted by stochastic acceleration and power laws which could result from acceleration at large-scale planar shocks was used, with the thick-target model. It is assumed that in the interaction region the accelerated particles are isotropic. The neutron-to-2.223 MeV photon conversion factors for various flare locations on the Sun are derived by averaging conversion factors over these spectra. Comparing calculations with data confirms that for most gamma-ray flares the bulk of the accelerated particles remain trapped at the Sun and that these particles have spectra similar to the spectra of flare particles observed in interplanetary space.

  18. Laser-driven high-energy-density deuterium and tritium ions for neutron production in a double-cone configuration

    NASA Astrophysics Data System (ADS)

    Hu, Li-Xiang; Yu, Tong-Pu; Shao, Fu-Qiu; Zhu, Qing-Jun; Yin, Yan; Ma, Yan-Yun

    2015-12-01

    By using two-dimensional particle-in-cell simulations, we investigate laser-driven ion acceleration and compression from a thin DT foil in a double-cone configuration. By using two counterpropagating laser pulses, it is shown that a double-cone structure can effectively guide, focus, and strengthen the incident laser pulses, resulting in the enhanced acceleration and compression of D+ and T+. Due to the ion Coulomb repulsion and the effective screening from the external laser electric fields, the transverse diffusion of ions is significantly suppressed. Finally, the peak energy density of the compressed ions exceeds 2.73 × 1016 J/m3, which is about five orders of magnitude higher than the threshold for high energy density physics, 1011 J/m3. Under this condition, DT fusion reactions are initiated and the neutron production rate per volume is estimated to be as high as 7.473 × 1035/m3 s according to Monte Carlo simulations. It is much higher than that of the traditional large neutron sources, which may facilitate many potential applications.

  19. Laser-driven high-energy-density deuterium and tritium ions for neutron production in a double-cone configuration

    SciTech Connect

    Hu, Li-Xiang; Yu, Tong-Pu Shao, Fu-Qiu; Yin, Yan; Ma, Yan-Yun; Zhu, Qing-Jun

    2015-12-15

    By using two-dimensional particle-in-cell simulations, we investigate laser-driven ion acceleration and compression from a thin DT foil in a double-cone configuration. By using two counterpropagating laser pulses, it is shown that a double-cone structure can effectively guide, focus, and strengthen the incident laser pulses, resulting in the enhanced acceleration and compression of D{sup +} and T{sup +}. Due to the ion Coulomb repulsion and the effective screening from the external laser electric fields, the transverse diffusion of ions is significantly suppressed. Finally, the peak energy density of the compressed ions exceeds 2.73 × 10{sup 16 }J/m{sup 3}, which is about five orders of magnitude higher than the threshold for high energy density physics, 10{sup 11 }J/m{sup 3}. Under this condition, DT fusion reactions are initiated and the neutron production rate per volume is estimated to be as high as 7.473 × 10{sup 35}/m{sup 3} s according to Monte Carlo simulations. It is much higher than that of the traditional large neutron sources, which may facilitate many potential applications.

  20. Electromagnetic waves from neutron stars and black holes driven by polar gravitational perturbations

    NASA Astrophysics Data System (ADS)

    Sotani, Hajime; Kokkotas, Kostas D.; Laguna, Pablo; Sopuerta, Carlos F.

    2014-03-01

    Neutron stars and black holes are the most compact astrophysical objects we can think of and as a consequence they are the main sources of gravitational waves. There are many astrophysically relevant scenarios in which these objects are immersed in or endowed with strong magnetic fields, in such a way that gravitational perturbations can couple to electromagnetic ones and can potentially trigger synergistic electromagnetic signatures. In a recent paper we derived the main equations for gravito-electromagnetic perturbations and studied in detail the case of polar electromagnetic perturbations driven by axial gravitational perturbations. In this paper we deal with the case of axial electromagnetic perturbations driven by polar black-hole or neutron stars oscillations, in which the energy emitted in case is considerably larger than in the previous case. In the case of neutron stars the phenomenon lasts considerably longer since the fluid acts as an energy reservoir that shakes the magnetic field for a timescale of the order of secs.

  1. A technology platform for translational research on laser driven particle accelerators for radiotherapy

    NASA Astrophysics Data System (ADS)

    Enghardt, W.; Bussmann, M.; Cowan, T.; Fiedler, F.; Kaluza, M.; Pawelke, J.; Schramm, U.; Sauerbrey, R.; Tünnermann, A.; Baumann, M.

    2011-05-01

    It is widely accepted that proton or light ion beams may have a high potential for improving cancer cure by means of radiation therapy. However, at present the large dimensions of electromagnetic accelerators prevent particle therapy from being clinically introduced on a broad scale. Therefore, several technological approaches among them laser driven particle acceleration are under investigation. Parallel to the development of suitable high intensity lasers, research is necessary to transfer laser accelerated particle beams to radiotherapy, since the relevant parameters of laser driven particle beams dramatically differ from those of beams delivered by conventional accelerators: The duty cycle is low, whereas the number of particles and thus the dose rate per pulse are high. Laser accelerated particle beams show a broad energy spectrum and substantial intensity fluctuations from pulse to pulse. These properties may influence the biological efficiency and they require completely new techniques of beam delivery and quality assurance. For this translational research a new facility is currently constructed on the campus of the university hospital Dresden. It will be connected to the department of radiooncology and host a petawatt laser system delivering an experimental proton beam and a conventional therapeutic proton cyclotron. The cyclotron beam will be delivered on the one hand to an isocentric gantry for patient treatments and on the other hand to an experimental irradiation site. This way the conventional accelerator will deliver a reference beam for all steps of developing the laser based technology towards clinical applicability.

  2. Guided post-acceleration of laser-driven ions by a miniature modular structure

    PubMed Central

    Kar, Satyabrata; Ahmed, Hamad; Prasad, Rajendra; Cerchez, Mirela; Brauckmann, Stephanie; Aurand, Bastian; Cantono, Giada; Hadjisolomou, Prokopis; Lewis, Ciaran L. S.; Macchi, Andrea; Nersisyan, Gagik; Robinson, Alexander P. L.; Schroer, Anna M.; Swantusch, Marco; Zepf, Matt; Willi, Oswald; Borghesi, Marco

    2016-01-01

    All-optical approaches to particle acceleration are currently attracting a significant research effort internationally. Although characterized by exceptional transverse and longitudinal emittance, laser-driven ion beams currently have limitations in terms of peak ion energy, bandwidth of the energy spectrum and beam divergence. Here we introduce the concept of a versatile, miniature linear accelerating module, which, by employing laser-excited electromagnetic pulses directed along a helical path surrounding the laser-accelerated ion beams, addresses these shortcomings simultaneously. In a proof-of-principle experiment on a university-scale system, we demonstrate post-acceleration of laser-driven protons from a flat foil at a rate of 0.5 GeV m−1, already beyond what can be sustained by conventional accelerator technologies, with dynamic beam collimation and energy selection. These results open up new opportunities for the development of extremely compact and cost-effective ion accelerators for both established and innovative applications. PMID:27089200

  3. Guided post-acceleration of laser-driven ions by a miniature modular structure.

    PubMed

    Kar, Satyabrata; Ahmed, Hamad; Prasad, Rajendra; Cerchez, Mirela; Brauckmann, Stephanie; Aurand, Bastian; Cantono, Giada; Hadjisolomou, Prokopis; Lewis, Ciaran L S; Macchi, Andrea; Nersisyan, Gagik; Robinson, Alexander P L; Schroer, Anna M; Swantusch, Marco; Zepf, Matt; Willi, Oswald; Borghesi, Marco

    2016-01-01

    All-optical approaches to particle acceleration are currently attracting a significant research effort internationally. Although characterized by exceptional transverse and longitudinal emittance, laser-driven ion beams currently have limitations in terms of peak ion energy, bandwidth of the energy spectrum and beam divergence. Here we introduce the concept of a versatile, miniature linear accelerating module, which, by employing laser-excited electromagnetic pulses directed along a helical path surrounding the laser-accelerated ion beams, addresses these shortcomings simultaneously. In a proof-of-principle experiment on a university-scale system, we demonstrate post-acceleration of laser-driven protons from a flat foil at a rate of 0.5 GeV m(-1), already beyond what can be sustained by conventional accelerator technologies, with dynamic beam collimation and energy selection. These results open up new opportunities for the development of extremely compact and cost-effective ion accelerators for both established and innovative applications. PMID:27089200

  4. MCNP Neutron Simulations: The Effectiveness of the University of Kentucky Accelerator Laboratory Pit

    NASA Astrophysics Data System (ADS)

    Jackson, Daniel; Nguyen, Thien An; Hicks, S. F.; Rice, Ben; Vanhoy, J. R.

    2015-10-01

    The design of the Van de Graaff Particle Accelerator complex at the University of Kentucky is marked by the unique addition of a pit in the main neutron scattering room underneath the neutron source and detection shielding assembly. This pit was constructed as a neutron trap in order to decrease the amount of neutron flux within the laboratory. Such a decrease of background neutron flux effectively reduces as much noise as possible in detection of neutrons scattering off of desired samples to be studied. This project uses the Monte-Carlo N-Particle Transport Code (MCNP) to model the structure of the accelerator complex, gas cell, and the detector's collimator and shielding apparatus to calculate the neutron flux in various sections of the laboratory. Simulations were completed with baseline runs of 107 neutrons of energies 4 MeV and 17 MeV, produced respectively by 3H(p,n)3He and 3H(d,n)4He source reactions. In addition, a comparison model of the complex with simply a floor and no pit was designed, and the respective neutron fluxes of both models were calculated and compared. The results of the simulations seem to affirm the validity of the pit design in significantly reducing the overall neutron flux throughout the accelerator complex, which could be used in future designs to increase the precision and reliability of data. This project was supported in part by the DOE NEUP Grant NU-12-KY-UK-0201-05 and the Donald A. Cowan Physics Institute at the University of Dallas.

  5. Conceptual design of minor actinides burner with an accelerator-driven subcritical system.

    SciTech Connect

    Cao, Y.; Gohar, Y.

    2011-11-04

    In the environmental impact study of the Yucca Mountain nuclear waste repository, the limit of spent nuclear fuel (SNF) for disposal is assessed at 70,000 metric tons of heavy metal (MTHM), among which 63,000 MTHM are the projected SNF discharge from U.S. commercial nuclear power plants though 2011. Within the 70,000 MTHM of SNF in storage, approximately 115 tons would be minor actinides (MAs) and 585 tons would be plutonium. This study describes the conceptual design of an accelerator-driven subcritical (ADS) system intended to utilize (burn) the 115 tons of MAs. The ADS system consists of a subcritical fission blanket where the MAs fuel will be burned, a spallation neutron source to drive the fission blanket, and a radiation shield to reduce the radiation dose to an acceptable level. The spallation neutrons are generated from the interaction of a 1 GeV proton beam with a lead-bismuth eutectic (LBE) or liquid lead target. In this concept, the fission blanket consists of a liquid mobile fuel and the fuel carrier can be LBE, liquid lead, or molten salt. The actinide fuel materials are dissolved, mixed, or suspended in the liquid fuel carrier. Therefore, fresh fuel can be fed into the fission blanket to adjust its reactivity and to control system power during operation. Monte Carlo analyses were performed to determine the overall parameters of an ADS system utilizing LBE as an example. Steady-state Monte Carlo simulations were studied for three fission blanket configurations that are similar except that the loaded amount of actinide fuel in the LBE is either 5, 7, or 10% of the total volume of the blanket, respectively. The neutron multiplication factor values of the three configurations are all approximately 0.98 and the MA initial inventories are each approximately 10 tons. Monte Carlo burnup simulations using the MCB5 code were performed to analyze the performance of the three conceptual ADS systems. Preliminary burnup analysis shows that all three conceptual ADS

  6. Characterization of an accelerator neutron source based on the Be(d,n) reaction

    SciTech Connect

    Meadows, J.W.; Smith, D.L.

    1992-07-01

    Small accelerator neutron sources offer considerable potential for applied neutron radiography applications. Among the desirable features are relatively low costs, limited operating hazards, opportunities for tailoring primary neutron spectra, compactness and portability, and modest licensing requirements (compared to fission reactors). However, exploitation of this potential has been somewhat limited, in part, by incomplete knowledge of the primary-neutron yields and energy spectra from the favorable source reactions. This work describes an extensive experimental determination of zero-degree neutron yields and energy spectra from the {sup 9}Be(d,n) {sup 10}B source reaction, for incident deuterons of 2.6 to 7.0 MeV on a thick beryllium metal target. This information was acquired by means of time-of-flight measurements that were conducted with a calibrated uranium fission detector. Tables and plots of neutron-producing reaction data are presented. This information provides input which will be essential for applications involving the primary spectrum as well as for the design of neutron moderators and for calculation of thermal-neutron yield factors. Such analyses will be prerequisites in assessing the suitability of this source for various possible neutron radiography applications and, also, for assisting in the design of appropriate detectors to be used in neutron imaging devices.

  7. Characterization of an accelerator neutron source based on the Be(d,n) reaction

    SciTech Connect

    Meadows, J.W.; Smith, D.L.

    1992-01-01

    Small accelerator neutron sources offer considerable potential for applied neutron radiography applications. Among the desirable features are relatively low costs, limited operating hazards, opportunities for tailoring primary neutron spectra, compactness and portability, and modest licensing requirements (compared to fission reactors). However, exploitation of this potential has been somewhat limited, in part, by incomplete knowledge of the primary-neutron yields and energy spectra from the favorable source reactions. This work describes an extensive experimental determination of zero-degree neutron yields and energy spectra from the {sup 9}Be(d,n) {sup 10}B source reaction, for incident deuterons of 2.6 to 7.0 MeV on a thick beryllium metal target. This information was acquired by means of time-of-flight measurements that were conducted with a calibrated uranium fission detector. Tables and plots of neutron-producing reaction data are presented. This information provides input which will be essential for applications involving the primary spectrum as well as for the design of neutron moderators and for calculation of thermal-neutron yield factors. Such analyses will be prerequisites in assessing the suitability of this source for various possible neutron radiography applications and, also, for assisting in the design of appropriate detectors to be used in neutron imaging devices.

  8. Accelerator-Based Biological Irradiation Facility Simulating Neutron Exposure from an Improvised Nuclear Device.

    PubMed

    Xu, Yanping; Randers-Pehrson, Gerhard; Turner, Helen C; Marino, Stephen A; Geard, Charles R; Brenner, David J; Garty, Guy

    2015-10-01

    We describe here an accelerator-based neutron irradiation facility, intended to expose blood or small animals to neutron fields mimicking those from an improvised nuclear device at relevant distances from the epicenter. Neutrons are generated by a mixed proton/deuteron beam on a thick beryllium target, generating a broad spectrum of neutron energies that match those estimated for the Hiroshima bomb at 1.5 km from ground zero. This spectrum, dominated by neutron energies between 0.2 and 9 MeV, is significantly different from the standard reactor fission spectrum, as the initial bomb spectrum changes when the neutrons are transported through air. The neutron and gamma dose rates were measured using a custom tissue-equivalent gas ionization chamber and a compensated Geiger-Mueller dosimeter, respectively. Neutron spectra were evaluated by unfolding measurements using a proton-recoil proportional counter and a liquid scintillator detector. As an illustration of the potential use of this facility we present micronucleus yields in single divided, cytokinesis-blocked human peripheral lymphocytes up to 1.5 Gy demonstrating 3- to 5-fold enhancement over equivalent X-ray doses. This facility is currently in routine use, irradiating both mice and human blood samples for evaluation of neutron-specific biodosimetry assays. Future studies will focus on dose reconstruction in realistic mixed neutron/photon fields. PMID:26414507

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

    PubMed

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

    2015-12-01

    The iBNCT project team with University of Tsukuba is developing an accelerator-based neutron source. Regarding neutron target material, our project has applied beryllium. To deal with large heat load and blistering of the target system, we developed a three-layer structure for the target system that includes a blistering mitigation material between the beryllium used as the neutron generator and the copper heat sink. The three materials were bonded through diffusion bonding using a hot isostatic pressing method. Based on several verifications, our project chose palladium as the intermediate layer. A prototype of the neutron target system was produced. We will verify that sufficient neutrons for BNCT treatment are generated by the device in the near future. PMID:26260448

  10. Applying nonlinear diffusion acceleration to the neutron transport k-Eigenvalue problem with anisotropic scattering

    SciTech Connect

    Willert, Jeffrey; Park, H.; Taitano, William

    2015-10-12

    High-order/low-order (or moment-based acceleration) algorithms have been used to significantly accelerate the solution to the neutron transport k-eigenvalue problem over the past several years. Recently, the nonlinear diffusion acceleration algorithm has been extended to solve fixed-source problems with anisotropic scattering sources. In this paper, we demonstrate that we can extend this algorithm to k-eigenvalue problems in which the scattering source is anisotropic and a significant acceleration can be achieved. Lastly, we demonstrate that the low-order, diffusion-like eigenvalue problem can be solved efficiently using a technique known as nonlinear elimination.

  11. ESS-Bilbao light-ion linear accelerator and neutron source: design and applications

    NASA Astrophysics Data System (ADS)

    Abad, E.; Arredondo, I.; Badillo, I.; Belver, D.; Bermejo, F. J.; Bustinduy, I.; Cano, D.; Cortazar, D.; de Cos, D.; Djekic, S.; Domingo, S.; Echevarria, P.; Eguiraun, M.; Etxebarria, V.; Fernandez, D.; Fernandez, F. J.; Feuchtwanger, J.; Garmendia, N.; Harper, G.; Hassanzadegan, H.; Jugo, J.; Legarda, F.; Magan, M.; Martinez, R.; Megia, A.; Muguira, L.; Mujika, G.; Muñoz, J. L.; Ortega, A.; Ortega, J.; Perlado, M.; Portilla, J.; Rueda, I.; Sordo, F.; Toyos, V.; Vizcaino, A.

    2011-10-01

    The baseline design for the ESS-Bilbao light-ion linear accelerator and neutron source has been completed and the normal conducting section of the linac is at present under construction. The machine has been designed to be compliant with ESS specifications following the international guidelines of such project as described in Ref. [1]. The new accelerator facility in Bilbao will serve as a base for support of activities on accelerator physics carried out in Spain and southern Europe in the frame of different ongoing international collaborations. Also, a number of applications have been envisaged in the new Bilbao facility for the outgoing light ion beams as well as from fast neutrons produced by low-energy neutron-capture targets, which are briefly described.

  12. Shielding design of a treatment room for an accelerator-based neutron source for BNCT

    SciTech Connect

    Evans, J.F.; Blue, T.E.

    1995-12-31

    For several years, research has been ongoing in the Ohio State University (OSU) Nuclear Engineering Program toward the development of an accelerator-based irradiation facility (ANIF) neutron source for boron neutron capture therapy (BNCT). The ANIF, which is planned to be built in a hospital, has been conceptually designed and analyzed. After Qu, an OSU researcher, determined that the shielding design of a 6-MV X-ray treatment room was inadequate to protect personnel from an accelerator neutron source operating at 30 mA, we decided to analyze and determine the shielding requirements of a treatment room for an ANIF. We determined the amount of shielding that would be sufficient to protect facility personnel from excessive radiation exposure caused by operation of the accelerator at 30 mA.

  13. Summary Report of Working Group 4: e-Beam Driven Accelerators

    SciTech Connect

    Yakimenko, V.; Ischebeck, R.

    2006-11-27

    The working group considered high transformer ration schemes for an afterburner based on the design of a future linear collider. The main linac produces high charge beams of 100 GeV. A multiple stage plasma based accelerator would accelerate a portion of this beam to 500 GeV. The length of each plasma stage is expected to be of the order of a few meters while the isochronous beam transport required for multiple stages would occupy about a kilometer. Discussions in the working group were centered on issues to be addressed: ion motion in the plasma channel, positron side of accelerator ... The state of present e-beam driven plasma and dielectric Wakefield accelerators is very mature and closely resembles parameters of the afterburner for ILC. The main result of this working group is a multistage afterburner scheme of an afterburner for ILC and discussion of the experimental program to address main issues.

  14. Summary Report of Working Group 4: e-Beam Driven Accelerators

    NASA Astrophysics Data System (ADS)

    Yakimenko, V.; Ischebeck, R.

    2006-11-01

    The working group considered high transformer ration schemes for an afterburner based on the design of a future linear collider. The main linac produces high charge beams of 100 GeV. A multiple stage plasma based accelerator would accelerate a portion of this beam to 500 GeV. The length of each plasma stage is expected to be of the order of a few meters while the isochronous beam transport required for multiple stages would occupy about a kilometer. Discussions in the working group were centered on issues to be addressed: ion motion in the plasma channel, positron side of accelerator … The state of present e-beam driven plasma and dielectric Wakefield accelerators is very mature and closely resembles parameters of the afterburner for ILC. The main result of this working group is a multistage afterburner scheme of an afterburner for ILC and discussion of the experimental program to address main issues.

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

    SciTech Connect

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

    1998-08-01

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

  16. Accelerator mass spectrometry of 36Cl produced by neutrons from the Hiroshima bomb.

    PubMed

    Kato, K; Habara, M; Yoshizawa, Y; Biebel, U; Haberstock, G; Heinzl, J; Korschinek, G; Morinaga, H; Nolte, E

    1990-10-01

    Accelerator mass spectrometry was performed at the Munich tandem laboratory to determine 36Cl/Cl ratios of samples from a tombstone exposed to neutrons from the Hiroshima bomb. The ratios were determined from the surface to deeper positions. The depth profile of 36Cl/Cl can be used for estimating the neutron energy distribution and intensity near the hypocentre in Hiroshima. PMID:1976726

  17. First experimental results from 2 MeV proton tandem accelerator for neutron production.

    PubMed

    Kudryavtsev, A; Belchenko, Yu; Burdakov, A; Davydenko, V; Ivanov, A; Khilchenko, A; Konstantinov, S; Krivenko, A; Kuznetsov, A; Mekler, K; Sanin, A; Shirokov, V; Sorokin, I; Sulyaev, Yu; Tiunov, M

    2008-02-01

    A 2 MeV proton tandem accelerator with vacuum insulation was developed and first experiments are carried out in the Budker Institute of Nuclear Physics (Novosibirsk). The accelerator is designed for neutron production via reaction (7)Li(p,n)(7)Be for the boron neutron-capture therapy of the brain tumors, and for explosive detection based on 9.1724 MeV resonance gamma, which are produced via reaction (13)C(p,gamma)(14)N, absorption in nitrogen. PMID:18315262

  18. First experimental results from 2 MeV proton tandem accelerator for neutron production

    SciTech Connect

    Kudryavtsev, A.; Belchenko, Yu.; Burdakov, A.; Davydenko, V.; Ivanov, A.; Khilchenko, A.; Konstantinov, S.; Krivenko, A.; Kuznetsov, A.; Mekler, K.; Sanin, A.; Shirokov, V.; Sorokin, I.; Sulyaev, Yu.; Tiunov, M.

    2008-02-15

    A 2 MeV proton tandem accelerator with vacuum insulation was developed and first experiments are carried out in the Budker Institute of Nuclear Physics (Novosibirsk). The accelerator is designed for neutron production via reaction {sup 7}Li(p,n){sup 7}Be for the boron neutron-capture therapy of the brain tumors, and for explosive detection based on 9.1724 MeV resonance gamma, which are produced via reaction {sup 13}C(p,{gamma}){sup 14}N, absorption in nitrogen.

  19. Tandem-ESQ for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT)

    SciTech Connect

    Kreiner, A. J.; Kwan, J. W.; Henestroza, E.; Burlon, A. A.; Di Paolo, H.; Minsky, D.; Debray, M.; Valda, A.; Somacal, H. R.

    2007-02-12

    A folded tandem, with 1.25 MV terminal voltage, combined with an ElectroStatic Quadrupole (ESQ) chain is being proposed as a machine for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT). The machine is shown to be capable of accelerating a 30 mA proton beam to 2.5 MeV. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the on the 7Li(p,n)7Be reaction, to perform BNCT treatment for deep seated tumors in less than an hour.

  20. Three-dimensional Dielectric Photonic Crystal Structures for Laser-driven Acceleration

    SciTech Connect

    Cowan, Benjamin M.; /Tech-X, Boulder /SLAC

    2007-12-14

    We present the design and simulation of a three-dimensional photonic crystal waveguide for linear laser-driven acceleration in vacuum. The structure confines a synchronous speed-of-light accelerating mode in both transverse dimensions. We report the properties of this mode, including sustainable gradient and optical-to-beam efficiency. We present a novel method for confining a particle beam using optical fields as focusing elements. This technique, combined with careful structure design, is shown to have a large dynamic aperture and minimal emittance growth, even over millions of optical wavelengths.

  1. Energy Efficiency of an Intracavity Coupled, Laser-Driven Linear Accelerator Pumped by an External Laser

    SciTech Connect

    Neil Na, Y.C.; Siemann, R.H.; Byer, R.L.; /Stanford U., Phys. Dept.

    2005-06-24

    We calculate the optimum energy efficiency of a laser-driven linear accelerator by adopting a simple linear model. In the case of single bunch operation, the energy efficiency can be enhanced by incorporating the accelerator into a cavity that is pumped by an external laser. In the case of multiple bunch operation, the intracavity configuration is less advantageous because the strong wakefield generated by the electron beam is also recycled. Finally, the calculation indicates that the luminosity of a linear collider based on such a structure is comparably small if high efficiency is desired.

  2. THE ENEA ADS PROJECT:. Accelerator Driven System Prototype R&D and Industrial Program

    NASA Astrophysics Data System (ADS)

    Gherardi, Giuseppe

    2001-11-01

    Hybrid reactors (Accelerator Driven Sub-critical Systems, ADS), coupling an accelerator with a target and a sub-critical reactor, could simultaneously burn minor actinides and transmute long-lived fission products, while producing a consistent amount of electrical energy. A group of Italian research and development (R&D) organizations and industries have set up a team, which is studying the design issues related to the construction of an 80 MWth Experimental Facility. The planned activities and the (tentative) time schedule of the Italian program are presented.

  3. Impulse-scaling in a laser-driven in-tube accelerator

    NASA Astrophysics Data System (ADS)

    Sasoh, A.; Urabe, N.; Kim, S. S. M.; Jeung, I.-S.

    The laser-driven in-tube accelerator (LITA) is a unique device for laser propulsion. It is characterized by the acceleration of a projectile in a tube. The thrust performance can be improved by exploiting a confinement effect. In the experiment, a 3.0-g projectile is vertically launched, and the momentum coupling coefficient is measured for various monoatomic gases. The measured coupling coefficient is almost proportional to the reciprocal of the speed of sound. The same impulse generation characteristics are obtained in simplified situations that are analyzed based on conservation relations.

  4. Vertical Launch Performance of Laser-driven In-Tube Accelerator

    NASA Astrophysics Data System (ADS)

    Urabe, Naohide; Kim, Sukyum; Sasoh, Akihiro; Jeung, In-Seuck

    2003-05-01

    We studied the vertical launch performance of the Laser-driven In-Tube Accelerator (LITA). This device is primarily characterized by accelerating a projectile in a tube. Owing to the confinement effect, the thrust performance is enhanced. The driver gas can be specified and its pressure be turned so that the impulse performance is optimized. In the experiments, a 3.0-gram projectile was vertically launched. The effects of the projectile exit condition, the laser beam incident direction and the driver gas species were experimentally studied.

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

    NASA Astrophysics Data System (ADS)

    Patil, B. J.; Chavan, S. T.; Pethe, S. N.; Krishnan, R.; Bhoraskar, V. N.; Dhole, S. D.

    2011-12-01

    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-γ 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 (γ, 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 × 0, 10 × 10, 20 × 20, 30 × 30 and 40 × 40 cm 2, respectively. The maximum neutron dose equivalent is observed near the central axis of 30 × 30 cm 2 field size. This is 0.71% of the central axis photon dose rate of 0.34 Gy/min at 1 μA electron beam current.

  6. Analysis of accelerator based neutron spectra for BNCT using proton recoil spectroscopy

    SciTech Connect

    Wielopolski, L.; Ludewig, H.; Powell, J.R.; Raparia, D.; Alessi, J.G.; Lowenstein, D.I.

    1999-03-01

    Boron Neutron Capture Therapy (BNCT) is a promising binary treatment modality for high-grade primary brain tumors (glioblastoma multiforme, GM) and other cancers. BNCT employs a boron-10 containing compound that preferentially accumulates in the cancer cells in the brain. Upon neutron capture by {sup 10}B energetic alpha particles and triton released at the absorption site kill the cancer cell. In order to gain penetration depth in the brain Fairchild proposed, for this purpose, the use of energetic epithermal neutrons at about 10 keV. Phase 1/2 clinical trials of BNCT for GM are underway at the Brookhaven Medical Research Reactor (BMRR) and at the MIT Reactor, using these nuclear reactors as the source for epithermal neutrons. In light of the limitations of new reactor installations, e.g. cost, safety and licensing, and limited capability for modulating the reactor based neutron beam energy spectra, alternative neutron sources are being contemplated for wider implementation of this modality in a hospital environment. For example, accelerator based neutron sources offer the possibility of tailoring the neutron beams, in terms of improved depth-dose distributions, to the individual and offer, with relative ease, the capability of modifying the neutron beam energy and port size. In previous work new concepts for compact accelerator/target configuration were published. In this work, using the Van de Graaff accelerator the authors have explored different materials for filtering and reflecting neutron beams produced by irradiating a thick Li target with 1.8 to 2.5 MeV proton beams. However, since the yield and the maximum neutron energy emerging from the Li-7(p,n)Be-7 reaction increase with increase in the proton beam energy, there is a need for optimization of the proton energy versus filter and shielding requirements to obtain the desired epithermal neutron beam. The MCNP-4A computer code was used for the initial design studies that were verified with benchmark

  7. ANALYSIS OF ACCELERATOR BASED NEUTRON SPECTRA FOR BNCT USING PROTON RECOIL SPECTROSCOPY

    SciTech Connect

    WIELOPOLSKI,L.; LUDEWIG,H.; POWELL,J.R.; RAPARIA,D.; ALESSI,J.G.; LOWENSTEIN,D.I.

    1998-11-06

    Boron Neutron Capture Therapy (BNCT) is a promising binary treatment modality for high-grade primary brain tumors (glioblastoma multiforme, GM) and other cancers. BNCT employs a boron-10 containing compound that preferentially accumulates in the cancer cells in the brain. Upon neutron capture by {sup 10}B energetic alpha particles and triton released at the absorption site kill the cancer cell. In order to gain penetration depth in the brain Fairchild proposed, for this purpose, the use of energetic epithermal neutrons at about 10 keV. Phase I/II clinical trials of BNCT for GM are underway at the Brookhaven Medical Research Reactor (BMRR) and at the MIT Reactor, using these nuclear reactors as the source for epithermal neutrons. In light of the limitations of new reactor installations, e.g. cost, safety and licensing, and limited capability for modulating the reactor based neutron beam energy spectra alternative neutron sources are being contemplated for wider implementation of this modality in a hospital environment. For example, accelerator based neutron sources offer the possibility of tailoring the neutron beams, in terms of improved depth-dose distributions, to the individual and offer, with relative ease, the capability of modifying the neutron beam energy and port size. In previous work new concepts for compact accelerator/target configuration were published. In this work, using the Van de Graaff accelerator the authors have explored different materials for filtering and reflecting neutron beams produced by irradiating a thick Li target with 1.8 to 2.5 MeV proton beams. However, since the yield and the maximum neutron energy emerging from the Li-7(p,n)Be-7 reaction increase with increase in the proton beam energy, there is a need for optimization of the proton energy versus filter and shielding requirements to obtain the desired epithermal neutron beam. The MCNP-4A computer code was used for the initial design studies that were verified with benchmark

  8. Polymer gel dosimetry for neutron beam in the Neutron Exposure Accelerator System for Biological Effect Experiments (NASBEE)

    NASA Astrophysics Data System (ADS)

    Kawamura, H.; Sato, H.; Hamano, T.; Suda, M.; Yoshii, H.

    2015-01-01

    This study aimed to investigate whether gel dosimetry could be used to measure neutron beams. We irradiated a BANG3-type polymer gel dosimeter using neutron beams in the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) at the National Institute of Radiological Sciences (NIRS) in Japan. First, the polymer gels were irradiated from 0 to 7.0 Gy to investigate the dose-R2 responses. Irradiated gels were evaluated using 1.5-T magnetic resonance R2 images. Second, the polymer gels were irradiated to 1.0, 3.0, and 5.0 Gy to acquire a depth-R2 response curve. The dose-R2 response curve was linear up to approximately 7 Gy, with a slope of 1.25 Gy-1·s-1. Additionally, compared with the photon- irradiated gels, the neutron-irradiated gels had lower R2 values. The acquired depth-R2 curves of the central axis from the 3.0- and 5.0-Gy neutron dose-irradiated gels exhibited an initial build-up. Although, a detailed investigation is needed, polymer gel dosimetry is effective for measuring the dose-related R2 linearity and depth-R2 relationships of neutron beams.

  9. High power neutron production targets

    SciTech Connect

    Wender, S.

    1996-06-01

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

  10. Measurements of fusion neutrons from Magnetized Liner Inertial Fusion Experiments on the Z accelerator

    NASA Astrophysics Data System (ADS)

    Hahn, K. D.; Chandler, G. A.; Ruiz, C. L.; Gomez, M. R.; Slutz, S. A.; Sefkow, A. B.; Sinars, D. B.; Hansen, S. B.; Knapp, P. F.; Schmit, P. F.; Harding, E. C.; Awe, T. J.; Torres, J. A.; Jones, B.; Bur, J. A.; Cooper, G. W.; Styron, J. D.; Glebov, V. Yu.

    2015-11-01

    Strong evidence of thermonuclear neutron production has been observed during Magnetized Liner Inertial Fusion (MagLIF) experiments on the Z accelerator. So far, these experiments have utilized deuterium fuel and produced primary DD fusion neutron yields up to 2e12 with electron and ion stagnation temperatures in the 2-3 keV range. We present MagLIF neutron measurements and compare to other data and implosion simulations. In addition to primary DD and secondary DT yields and ion temperatures, other complex physics regarding the degree of fuel magnetization and liner density are elucidated by the neutron measurements. Neutron diagnostic development for deuterium and future deuterium-tritium fuel experiments are also discussed. Sandia is sponsored by the U.S. DOE's NNSA under contract DE-AC04-94AL85000.

  11. Study of muon-induced neutron production using accelerator muon beam at CERN

    SciTech Connect

    Nakajima, Y.; Lin, C. J.; Ochoa-Ricoux, J. P.; Draeger, E.; White, C. G.; Luk, K. B.; Steiner, H.

    2015-08-17

    Cosmogenic muon-induced neutrons are one of the most problematic backgrounds for various underground experiments for rare event searches. In order to accurately understand such backgrounds, experimental data with high-statistics and well-controlled systematics is essential. We performed a test experiment to measure muon-induced neutron production yield and energy spectrum using a high-energy accelerator muon beam at CERN. We successfully observed neutrons from 160 GeV/c muon interaction on lead, and measured kinetic energy distributions for various production angles. Works towards evaluation of absolute neutron production yield is underway. This work also demonstrates that the setup is feasible for a future large-scale experiment for more comprehensive study of muon-induced neutron production.

  12. Simulation study of accelerator based quasi-mono-energetic epithermal neutron beams for BNCT.

    PubMed

    Adib, M; Habib, N; Bashter, I I; El-Mesiry, M S; Mansy, M S

    2016-01-01

    Filtered neutron techniques were applied to produce quasi-mono-energetic neutron beams in the energy range of 1.5-7.5 keV at the accelerator port using the generated neutron spectrum from a Li (p, n) Be reaction. A simulation study was performed to characterize the filter components and transmitted beam lines. The feature of the filtered beams is detailed in terms of optimal thickness of the primary and additive components. A computer code named "QMNB-AS" was developed to carry out the required calculations. The filtered neutron beams had high purity and intensity with low contamination from the accompanying thermal, fast neutrons and γ-rays. PMID:26474209

  13. Fusion-neutron measurements for magnetized liner inertial fusion experiments on the Z accelerator

    DOE PAGESBeta

    Hahn, K. D.; Chandler, G. A.; Ruiz, C. L.; Cooper, G. W.; Gomez, M. R.; Slutz, S.; Sefkow, A. B.; Sinars, D. B.; Hansen, S. B.; Knapp, P. F.; et al

    2016-05-01

    Several magnetized liner inertial fusion (MagLIF) experiments have been conducted on the Z accelerator at Sandia National Laboratories since late 2013. Measurements of the primary DD (2.45 MeV) neutrons for these experiments suggest that the neutron production is thermonuclear. Primary DD yields up to 3e12 with ion temperatures ~2-3 keV have been achieved. Measurements of the secondary DT (14 MeV) neutrons indicate that the fuel is significantly magnetized. Measurements of down-scattered neutrons from the beryllium liner suggest ρRliner ~ 1g/cm2. Neutron bang times, estimated from neutron time-of-flight (nTOF) measurements, coincide with peak x-ray production. Furthermore, plans to improve and expandmore » the Z neutron diagnostic suite include neutron burn-history diagnostics, increased sensitivity and higher precision nTOF detectors, and neutron recoil-based yield and spectral measurements.« less

  14. Multidimensional supernova simulations with approximative neutrino transport. I. Neutron star kicks and the anisotropy of neutrino-driven explosions in two spatial dimensions

    NASA Astrophysics Data System (ADS)

    Scheck, L.; Kifonidis, K.; Janka, H.-Th.; Müller, E.

    2006-10-01

    We study hydrodynamic instabilities during the first seconds of core-collapse supernovae by means of 2D simulations with approximative neutrino transport and boundary conditions that parameterize the effects of the contracting neutron star and allow us to obtain sufficiently strong neutrino heating and, hence, neutrino-driven explosions. Confirming more idealised studies, as well as supernova simulations with spectral transport, we find that random seed perturbations can grow by hydrodynamic instabilities to a globally asymmetric mass distribution in the region between the nascent neutron star and the accretion shock, leading to a dominance of dipole (l=1) and quadrupole (l=2) modes in the explosion ejecta, provided the onset of the supernova explosion is sufficiently slower than the growth time scale of the low-mode instability. By gravitational and hydrodynamic forces, the anisotropic mass distribution causes an acceleration of the nascent neutron star, which lasts for several seconds and can propel the neutron star to velocities of more than 1000 km s-1. Because the explosion anisotropies develop chaotically and change by small differences in the fluid flow, the magnitude of the kick varies stochastically. No systematic dependence of the average neutron star velocity on the explosion energy or the properties of the considered progenitors is found. Instead, the anisotropy of the mass ejection, and hence of the kick, seems to increase when the nascent neutron star contracts more quickly, and thus low-mode instabilities can grow more rapidly. Our more than 70 models separate into two groups, one with high and the other with low neutron star velocities and accelerations after one second of post-bounce evolution, depending on whether the l=1 mode is dominant in the ejecta or not. This leads to a bimodality of the distribution when the neutron star velocities are extrapolated to their terminal values. Establishing a link to the measured distribution of pulsar

  15. Temperature Profile of the Solution Vessel of an Accelerator-Driven Subcritical Fissile Solution System

    SciTech Connect

    Klein, Steven Karl; Determan, John C.

    2015-09-14

    Dynamic System Simulation (DSS) models of fissile solution systems have been developed and verified against a variety of historical configurations. DSS techniques have been applied specifically to subcritical accelerator-driven systems using fissile solution fuels of uranium. Initial DSS models were developed in DESIRE, a specialized simulation scripting language. In order to tailor the DSS models to specifically meet needs of system designers they were converted to a Visual Studio implementation, and one of these subsequently to National Instrument’s LabVIEW for human factors engineering and operator training. Specific operational characteristics of subcritical accelerator-driven systems have been examined using a DSS model tailored to this particular class using fissile fuel.

  16. An innovative accelerator-driven inertial electrostatic confinement device using converging ion beams

    SciTech Connect

    Bauer, T. H.; Wigeland, R. A.

    1999-12-08

    Fundamental physics issues facing development of fusion power on a small-scale are assessed with emphasis on the idea of Inertial Electrostatic Confinement (IEC). The authors propose a new concept of accelerator-driven IEC fusion, termed Converging Beam Inertial Electrostatic Confinement (CB-IEC). CB-IEC offers a number of innovative features that make it an attractive pathway toward resolving fundamental physics issues and assessing the ultimate viability of the IEC concept for power generation.

  17. Summary report : working group 5 on 'electron beam-driven plasma and structure based acceleration concepts'.

    SciTech Connect

    Conde, M. E.; Katsouleas, T.

    2000-10-19

    The talks presented and the work performed on electron beam-driven accelerators in plasmas and structures are summarized. Highlights of the working group include new experimental results from the E-157 Plasma Wakefield Experiment, the E-150 Plasma Lens Experiment and the Argonne Dielectric Structure Wakefield experiments. The presentations inspired discussion and analysis of three working topics: electron hose instability, ion channel lasers and the plasma afterburner.

  18. Dependence of Initial Plasma Size on Laser-driven In-Tube Accelerator (LITA) Performance

    SciTech Connect

    Kim, Sukyum; Jeung, In-Seuck; Ohtani, Toshiro; Sasoh, Akihiro; Choi, Jeong-Yeol

    2004-03-30

    At Tohoku University, experiments of Laser-driven In-Tube Accelerator (LITA) have been carried out. In order to observe the initial state of plasma and blast wave, the visualization experiment was carried out using the shadowgraph method. In this paper, dependency of initial plasma size on LITA performance is investigated numerically. The plasma size is estimated using shadowgraph images and the numerical results are compared with the experimental data of pressure measurement and results of previous modeling.

  19. Dependence of Initial Plasma Size on Laser-driven In-Tube Accelerator (LITA) Performance

    NASA Astrophysics Data System (ADS)

    Kim, Sukyum; Ohtani, Toshiro; Sasoh, Akihiro; Jeung, In-Seuck; Choi, Jeong-Yeol

    2004-03-01

    At Tohoku University, experiments of Laser-driven In-Tube Accelerator (LITA) have been carried out. In order to observe the initial state of plasma and blast wave, the visualization experiment was carried out using the shadowgraph method. In this paper, dependency of initial plasma size on LITA performance is investigated numerically. The plasma size is estimated using shadowgraph images and the numerical results are compared with the experimental data of pressure measurement and results of previous modeling.

  20. Dynamic analysis of an accelerator-driven fluid-fueled subcritical radioactive waste burning system

    SciTech Connect

    Woosley, M.L. Jr.; Rydin, R.A.

    1998-05-01

    The recent revival of interest in accelerator-driven subcritical fluid-fueled systems is documented. Several important applications of these systems are mentioned, and this is used to motivate the need for dynamic analysis of the nuclear kinetics of such systems. A physical description of the Los alamos National Laboratory accelerator-based conversion (ABC) concept is provided. This system is used as the basis for the kinetics study in this research. The current approach to the dynamic simulation of an accelerator-driven subcritical fluid-fueled system includes four functional elements: a discrete ordinates model is used to calculate the flux distribution for the source-driven system; a nodal convection model is used to calculate time-dependent isotope and temperature distributions that impact reactivity; a nodal importance weighting model is used to calculate the reactivity impact of temperature and isotope distributions and to feed this information back to the time-dependent nodal convection model; and a transient driver is used to simulate transients, model the balance of plant, and record simulation data. Specific transients that have been analyzed with the current modeling system are discussed. These transients include loss-of-flow and loss-of-cooling accidents, xenon and samarium transients, and cold-plug and overfueling events. The results of various transients have uncovered unpredictable behavior, unresolved design issues, and the need for active control. The need for the development of a nodal-coupling spatial kinetics model is mentioned.

  1. Nonlinear Acceleration Methods for Even-Parity Neutron Transport

    SciTech Connect

    W. J. Martin; C. R. E. De Oliveira; H. Park

    2010-05-01

    Convergence acceleration methods for even-parity transport were developed that have the potential to speed up transport calculations and provide a natural avenue for an implicitly coupled multiphysics code. An investigation was performed into the acceleration properties of the introduction of a nonlinear quasi-diffusion-like tensor in linear and nonlinear solution schemes. Using the tensor reduced matrix as a preconditioner for the conjugate gradients method proves highly efficient and effective. The results for the linear and nonlinear case serve as the basis for further research into the application in a full three-dimensional spherical-harmonics even-parity transport code. Once moved into the nonlinear solution scheme, the implicit coupling of the convergence accelerated transport method into codes for other physics can be done seamlessly, providing an efficient, fully implicitly coupled multiphysics code with high order transport.

  2. CMFD acceleration of spatial domain-decomposed neutron transport problems

    SciTech Connect

    Kelley, B. W.; Larsen, E. W.

    2012-07-01

    A significant limitation to parallelizing the solution of neutron transport problems is the need for sweeps across the entirety of the problem domain. Angular domain decomposition is common practice, as the equations for each direction are independent aside from their shared scattering/fission source. Accordingly, spatial domain decomposition does not naturally arise in the transport equations and is therefore less frequent in practice. In this paper, we show that a neutron transport domain can be straightforwardly divided into independent, parallelizable sweep regions, globally linked with the standard CMFD method, with an additional update equation. We verify, theoretically (via Fourier analysis) and computationally, that the convergence properties of this method are stable and nominally as rapid as standard CMFD. (authors)

  3. Optimization of Drive-Bunch Current Profile for Enhanced Transformer Ratio in Beam-Driven Acceleration Techniques

    SciTech Connect

    Lemery, F.; Mihalcea, D.; Prokop, C.R.; Piot, P.; /Northern Illinois U. /Fermilab

    2012-07-08

    In recent years, wakefield acceleration has gained attention due to its high acceleration gradients and cost effectiveness. In beam-driven wakefield acceleration, a critical parameter to optimize is the transformer ratio. It has been shown that current shaping of electron beams allows for enhanced (> 2) transformer ratios. In this paper we present the optimization of the pulse shape of the drive bunch for dielectric-wakefield acceleration.

  4. Fabrication of nanostructured targets for improved laser-driven proton acceleration

    NASA Astrophysics Data System (ADS)

    Barberio, M.; Scisciò, M.; Veltri, S.; Antici, P.

    2016-07-01

    In this work, we present a novel realization of nanostructured targets suitable for improving laser-driven proton acceleration experiments, in particular with regard to the Target-Normal-Sheath Acceleration (TNSA) acceleration mechanism. The nanostructured targets, produced as films, are realized by a simpler and cheaper method than using conventional lithographic techniques. The growth process includes a two step approach for the production of the gold nanoparticle layers: 1) Laser Ablation in Solution and 2) spray-dry technique using a colloidal solution on target surfaces (Aluminum, Mylar and Multi Walled Carbon Nanotube). The obtained nanostructured films appear, at morphological and chemical analysis, uniformly nanostructured and the nanostructure distributed on the target surfaces without presence of oxides or external contaminants. The obtained targets show a broad optical absorption in all the visible region and a surface roughness that is two times greater than non-nanostructured targets, enabling a greater laser energy absorption during the laser-matter interaction experiments producing the laser-driven proton acceleration.

  5. LASER WAKEFIELD ACCELERATION DRIVEN BY ATF CO2 LASER (STELLA-LW).

    SciTech Connect

    KIMURA,W.D.; ANDREEV,N.E.; BABZIEN,M.; BEN-ZVI,I.; ET AL.

    2004-09-25

    A new experiment has begun that builds upon the successful Staged Electron Laser Acceleration (STELLA) experiment, which demonstrated high-trapping efficiency and narrow energy spread in a staged laser-driven accelerator. STELLA was based upon inverse free electron lasers (IFEL); the new experiment, called STELLA-LW, is based upon laser wakefield acceleration (LWFA). The first phase of STELLA-LW will be to demonstrate LWFA in a capillary discharge driven by the Brookhaven National Laboratory Accelerator Test Facility (ATF) terawatt CO{sub 2} laser beam. This will be the first time LWFA is conducted at 10.6-{micro}m laser wavelength. It will also be operating in an interesting pseudo-resonant regime where the laser pulse length is too long for resonant LWFA, but too short for self-modulated LWFA. Analysis has shown that in pseudo-resonant LWFA, pulse-steepening effects occur on the laser pulse that permits generation of strong wakefields. Various approaches are being explored for the capillary discharge including polypropylene and hydrogen-filled capillaries. Planned diagnostics for the experiment include coherent Thomson scattering (CTS) to detect the wakefield generation. This will be one of the first times CTS is used on a capillary discharge.

  6. Research program for the 660 MeV proton accelerator driven MOX-plutonium subcritical assembly

    NASA Astrophysics Data System (ADS)

    Barashenkov, V. S.; Buttsev, V. S.; Buttseva, G. L.; Dudarev, S. Ju.; Polanski, A.; Puzynin, I. V.; Sissakian, A. N.

    2000-07-01

    This paper presents the research program of the Experimental Accelerator Driven System (ADS), which employs a subcritical assembly and a 660 MeV proton accelerator operating in the Laboratory of Nuclear Problems at the Joint Institute for Nuclear Research in Dubna. Mixed-oxide (MOX) fuel (25% PuO2+75% UO2) designed for the BN-600 reactor use will be adopted for the core of the assembly. The present conceptual design of the experimental subcritical assembly is based on a core nominal unit capacity of 15 kW (thermal). This corresponds to the multiplication coefficient keff=0.945, energetic gain G=30, and accelerator beam power of 0.5 kW.

  7. Free-electron laser driven by the LBNL laser-plasma accelerator

    SciTech Connect

    Schroeder, C. B.; Fawley, W. M.; Robinson, K. E.; Toth, Cs.; Gruener, F.; Bakeman, M.; Nakamura, K.; Esarey, E.; Leemans, W. P.

    2009-01-22

    A design of a compact free-electron laser (FEL), generating ultra-fast, high-peak flux, XUV pulses is presented. The FEL is driven by a high-current, 0.5 GeV electron beam from the Lawrence Berkeley National Laboratory (LBNL) laser-plasma accelerator, whose active acceleration length is only a few centimeters. The proposed ultra-fast source ({approx}10 fs) would be intrinsically temporally synchronized to the drive laser pulse, enabling pump-probe studies in ultra-fast science. Owing to the high current (> or approx.10 kA) of the laser-plasma-accelerated electron beams, saturated output fluxes are potentially greater than 10{sup 13} photons/pulse. Devices based both on self-amplified spontaneous emission and high-harmonic generated input seeds, to reduce undulator length and fluctuations, are considered.

  8. Coulomb-driven energy boost of heavy ions for laser-plasma acceleration.

    PubMed

    Braenzel, J; Andreev, A A; Platonov, K; Klingsporn, M; Ehrentraut, L; Sandner, W; Schnürer, M

    2015-03-27

    An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultrathin gold foils have been irradiated by an ultrashort laser pulse at a peak intensity of 8×10^{19}  W/  cm^{2}. Highly charged gold ions with kinetic energies up to >200  MeV and a bandwidth limited energy distribution have been reached by using 1.3 J laser energy on target. 1D and 2D particle in cell simulations show how a spatial dependence on the ion's ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a spatial distribution of the ionization inside the thin target, leading to a field enhancement for the heavy ions by Coulomb explosion. It is capable of explaining the energy boost of highly charged ions, enabling a higher efficiency for the laser-driven heavy ion acceleration. PMID:25860747

  9. Design of a free-electron laser driven by the LBNLlaser-plasma-accelerator

    SciTech Connect

    Schroeder, C.B.; Fawley, W.M.; Montgomery, A.L.; Robinson, K.E.; Gruner, F.; Bakeman, M.; Leemans, W.P.

    2007-09-10

    We discuss the design and current status of a compactfree-electron laser (FEL), generating ultra-fast, high-peak flux, VUVpulses driven by a high-current, GeV electron beam from the existingLawrence Berkeley National Laboratory (LBNL) laser-plasma accelerator,whose active acceleration length is only a few cm. The proposedultra-fast source would be intrinsically temporally synchronized to thedrive laser pulse, enabling pump-probe studies in ultra-fast science withpulse lengths of tens of fs. Owing to the high current (&10 kA) ofthe laser-plasma-accelerated electron beams, saturated output fluxes arepotentially greater than 1013 photons/pulse. Devices based both on SASEand high-harmonic generated input seeds, to reduce undulator length andfluctuations, are considered.

  10. Free-electron laser driven by the LBNL laser-plasma accelerator

    SciTech Connect

    Schroeder, C. B.; Fawley, W. M.; Gruner, F.; Bakeman, M.; Nakamura, K.; Robinson, K. E.; Toth, Cs.; Esarey, E.; Leemans, W. P.

    2008-08-04

    A design of a compact free-electron laser (FEL), generating ultra-fast, high-peak flux, XUV pulses is presented. The FEL is driven by ahigh-current, 0.5 GeV electron beam from the Lawrence Berkeley National Laboratory (LBNL) laser-plasma accelerator, whose active acceleration length is only a few centimeters. The proposed ultra-fast source (~;;10 fs) would be intrinsically temporally synchronized to the drive laser pulse, enabling pump-probe studies in ultra-fast science. Owing to the high current (>10 kA) of the laser-plasma-accelerated electron beams, saturated output fluxes are potentially greater than 10^13 photons/pulse. Devices based both on self-amplified spontaneous emission and high-harmonic generated input seeds, to reduce undulator length and fluctuations, are considered.

  11. The modeling of a linear multi-beam deuteron compact accelerator for neutron generation

    NASA Astrophysics Data System (ADS)

    Araujo, Wagner L.; Campos, Tarcisio P. R.

    2012-07-01

    There is a prominent interest in obtaining high-flux neutron generators due to its wide range of applications and possibilities. The beam current that reaches the target is one of the main factors for determining the performance of the generator. In the present paper we address the modeling of a deuteron compact accelerator for neutron generation underlying the electrode placement and providing an optimized multiple beam accelerator geometry. The methodology consists of electrode displacement calculations and simulations of the deuteron and neutron beam transport. A phenomenological model has been proposed based on experimental data, which provides two electrode configuration patterns. Both configurations were compared through electromagnetic simulations considering a single-beam accelerator-type. The configuration with highest ion current has led to a new geometry incorporating multiple beams. The final prototype presents an interesting beam profile achieving deuteron kinetic energy in the order of 180 keV and current up to 198 mA. Estimated yield for this generator was 1012 n/s. A shield was designed, based on Monte Carlo simulations. Dose calculation was appraised showing a neutron and photon dose rate of 7.73 and 14.50 mGy h-1 in front of 46 cm shield. The achieved design offers a suitable performance toward a compact high-flux neutron generator.

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

    PubMed

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

    2011-12-01

    A prototype of a compact Liquid-Lithium Target (LiLiT), which will possibly constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals, was built. The LiLiT setup is presently being commissioned at Soreq Nuclear Research Center (SNRC). The liquid-lithium target will produce neutrons through the (7)Li(p,n)(7)Be reaction and it will overcome the major problem of removing the thermal power generated using a high-intensity proton beam (>10 kW), necessary for sufficient neutron flux. In off-line circulation tests, the liquid-lithium loop generated a stable lithium jet at high velocity, on a concave supporting wall; the concept will first be tested using a high-power electron beam impinging on the lithium jet. High intensity proton beam irradiation (1.91-2.5 MeV, 2-4 mA) will take place at Soreq Applied Research Accelerator Facility (SARAF) superconducting linear accelerator currently in construction at SNRC. Radiological risks due to the (7)Be produced in the reaction were studied and will be handled through a proper design, including a cold trap and appropriate shielding. A moderator/reflector assembly is planned according to a Monte Carlo simulation, to create a neutron spectrum and intensity maximally effective to the treatment and to reduce prompt gamma radiation dose risks. PMID:21459008

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

    NASA Astrophysics Data System (ADS)

    Cauble, Scott; Poehlmann, Flavio; Rieker, Gregory; Cappelli, Mark

    2011-10-01

    This poster presents a method to measure neutron yield from a coaxial plasma accelerator. Stored electrical energies between 1 and 19 kJ are discharged within a few microseconds across the electrodes of the coaxial gun, accelerating deuterium gas samples to plasma beam energies well beyond the keV energy range. The focus of this study is to examine the interaction of the plasma beam with a deuterated target by designing and fabricating a detector to measure neutron yield. Given the strong electromagnetic pulse associated with our accelerator, indirect measurement of neutrons via threshold-dependent nuclear activation serves as both a reliable and definitive indicator of high-energy particles for our application. Upon bombardment with neutrons, discs or stacks of metal foils placed near the deuterated target undergo nuclear activation reactions, yielding gamma-emitting isotopes whose decay is measured by a scintillation detector system. By collecting gamma ray spectra over time and considering nuclear cross sections, the magnitude of the original neutron pulse is inferred.

  14. Cross section for inelastic neutron ''acceleration'' by {sup 178}Hf{sup m2}

    SciTech Connect

    Karamian, S. A.; Carroll, J. J.

    2011-02-15

    The scattering of thermal neutrons from isomeric nuclei may include events in which the outgoing neutrons have increased kinetic energy. This process has been called inelastic neutron acceleration, or INNA, and occurs when the final nucleus, after emission of the neutron, is left in a state with lower energy than that of the isomer. The result, therefore, is an induced depletion of the isomer to the ground state. A cascade of several {gamma}'s must accompany the neutron emission to release the high angular momentum of the initial isomeric state. INNA was previously observed in a few cases, and the measured cross sections were only in modest agreement with theoretical estimates. The most recent measurement of an INNA cross section was {sigma}{sub INNA}=258{+-}58 b for neutron scattering by {sup 177}Lu{sup m}. In the present work, an INNA cross section of {sigma}{sub INNA}=168 {+-} 33 b was deduced from measurements of the total burnup of the high-spin, four-quasiparticle isomer {sup 178}Hf{sup m2} during irradiation by thermal neutrons. Statistical estimates for the probability of different reaction channels past neutron absorption were used in the analysis, and the deduced {sigma}{sub INNA} was compared to the theoretically predicted cross section.

  15. Space radiation accelerator experiments - The role of neutrons and light ions

    NASA Astrophysics Data System (ADS)

    Norbury, John W.; Slaba, Tony C.

    2014-10-01

    The importance of neutrons and light ions is considered when astronauts spend considerable time in thickly shielded regions of a spacecraft. This may be relevant for space missions both in and beyond low Earth orbit (LEO). In addition to heavy ion experiments at accelerators, it is suggested that an increased emphasis on experiments with lighter ions may be useful in reducing biological uncertainties.

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

    DOEpatents

    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.

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

    DOEpatents

    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.

  18. Laser-driven electron beam acceleration and future application to compact light sources

    SciTech Connect

    Hafz, N.; Jeong, T. M.; Lee, S. K.; Pae, K. H.; Sung, J. H.; Choi, I. W.; Yu, T. J.; Lee, J.; Jeong, Y. U.

    2009-07-25

    Laser-driven plasma accelerators are gaining much attention by the advanced accelerator community due to the potential these accelerators hold in miniaturizing future high-energy and medium-energy machines. In the laser wakefield accelerator (LWFA), the ponderomotive force of an ultrashort high intensity laser pulse excites a longitudinal plasma wave or bubble. Due to huge charge separation, electric fields created in the plasma bubble can be several orders of magnitude higher than those available in conventional microwave and RF-based accelerator facilities which are limited (up to approx100 MV/m) by material breakdown. Therefore, if an electron bunch is injected into the bubble in phase with its field, it will gain relativistic energies within an extremely short distance. Here, in the LWFA we show the generation of high-quality and high-energy electron beams up to the GeV-class within a few millimeters of gas-jet plasmas irradiated by tens of terawatt ultrashort laser pulses. Thus we realize approximately four orders of magnitude acceleration gradients higher than available by conventional technology. As a practical application of the stable high-energy electron beam generation, we are planning on injecting the electron beams into a few-meters long conventional undulator in order to realize compact X-ray synchrotron (immediate) and FEL (future) light sources. Stable laser-driven electron beam and radiation devices will surely open a new era in science, medicine and technology and will benefit a larger number of users in those fields.

  19. Selective Deuteron Acceleration and Neutron Production on the Vulcan PW Laser

    NASA Astrophysics Data System (ADS)

    Krygier, A. G.; Morrison, J. T.; Freeman, R. R.; Ahmed, H.; Green, J. A.; Alejo, A.; Kar, S.; Vassura, L.

    2014-10-01

    Fast neutron sources are important for a variety of applications including radiography and the detection of sensitive materials. Here we report on the results of an experiment using the Vulcan PW laser at Rutherford Appleton Laboratory to produce a nearly pure deuterium ion beam via Target Normal Sheath Acceleration. The typical contaminants are suppressed by freezing a μ m's thick layer of heavy water vapor (D2 O) onto a cryogenic target during the shot sequence. Neutrons were generated by colliding the accelerated deuterons were into secondary targets made of deuterated plastic in the pitcher-catcher arrangement. Absolute yields for deuterium ions and neutrons are reported. This work is supported by DOE Contract DE-FC02-04ER54789.

  20. Experimental and theoretical evaluation of accelerator based epithermal neutron yields for BNCT

    NASA Astrophysics Data System (ADS)

    Wielopolski, L.; Ludewig, H.; Powell, J. R.; Raparia, D.; Alessi, J. G.; Alburger, D. E.; Zucker, M. S.; Lowenstein, D. I.

    1999-06-01

    At BNL, we have evaluated the beam current required to produce a clinical neutron beam for Boron Neutron Capture Therapy (BNCT) with an epithermal neutron flux of 1012n/cm2/hr. Experiments were carried out on a Van de Graaff accelerator at the Radiological Research Accelerator Facility (RARAF) at Columbia University. A thick Li target was irradiated by protons with energies from 1.8 to 2.5 MeV. The neutron spectra resulting from the 7Li(p,n)7Be reaction, followed by various filter configurations, were determined by measuring pulse height distributions with a gas filled proton recoil spectrometer. These distributions were unfolded into neutron energy spectra using the PSNS code, from which the required beam currents were estimated to be about 5 mA. Results are in good agreement with calculations using the MCNP-4A transport code. In addition comparison was also made between the neutron flux obtained at the Brookhaven Medical Research Reactor (where clinical trials of BNCT are ongoing), and measurements at RARAF, using a 10BF3 detector in a phantom. These results also support the requirement for about 5 mA beam current.

  1. Neutron production using a pyroelectric driven target coupled with a gated field ionization source

    SciTech Connect

    Ellsworth, J. L.; Tang, V.; Falabella, S.; Naranjo, B.; Putterman, S.

    2013-04-19

    A palm sized, portable neutron source would be useful for widespread implementation of detection systems for shielded, special nuclear material. We present progress towards the development of the components for an ultracompact neutron generator using a pulsed, meso-scale field ionization source, a deuterated (or tritiated) titanium target driven by a negative high voltage lithium tantalate crystal. Neutron production from integrated tests using an ion source with a single, biased tungsten tip and a 3 Multiplication-Sign 1 cm, vacuum insulated crystal with a plastic deuterated target are presented. Component testing of the ion source with a single tip produces up to 3 nA of current. Dielectric insulation of the lithium tantalate crystals appears to reduce flashover, which should improve the robustness. The field emission losses from a 3 cm diameter crystal with a plastic target and 6 cm diameter crystal with a metal target are compared.

  2. Compact D-D Neutron Source-Driven Subcritical Multiplier and Beam-Shaping Assembly for Boron Neutron Capture Therapy

    SciTech Connect

    Francesco Ganda; Jasmina Vujic; Ehud Greenspan; Ka-Ngo Leung

    2010-12-01

    This work assesses the feasibility of using a small, safe, and inexpensive keff 0.98 subcritical fission assembly [subcritical neutron multiplier (SCM)] to amplify the treatment neutron beam intensity attainable from a compact deuterium-deuterium (D-D) fusion neutron source delivering [approximately]1012 n/s. The objective is to reduce the treatment time for deep-seated brain tumors to [approximately]1 h. The paper describes the optimal SCM design and two optimal beam-shaping assemblies (BSAs) - one designed to maximize the dose rate and the other designed to maximize the total dose that can be delivered to a deep-seated tumor. The neutron beam intensity amplification achieved with the optimized SCM and BSA results in an increase in the treatment dose rate by a factor of 18: from 0.56 Gy/h without the SCM to 10.1 Gy/h. The entire SCM is encased in an aluminum structure. The total amount of 20% enriched uranium required for the SCM is 8.5 kg, and the cost (not including fabrication) is estimated to be less than $60,000. The SCM power level is estimated at 400 W when driven by a 1012 n/s D-D neutron source. This translates into consumption of only [approximately]0.6% of the initially loaded 235U atoms during 50 years of continuous operation and implies that the SCM could operate continuously for the entire lifetime of the facility without refueling. Cooling the SCM does not pose a challenge; it may be accomplished by natural circulation as the maximum heat flux is only 0.034 W/cm2.

  3. Investigation of laser ion acceleration inside irradiated solid targets by neutron spectroscopy

    SciTech Connect

    Youssef, A.; Kodama, R.; Tampo, M.

    2006-03-15

    Origins and acceleration directions of accelerated ions inside solid LiF, CH-LiF, and LiF-CH targets irradiated by a 450 fs, 20 J, 1053 nm laser at an intensity of 3x10{sup 18} W/cm{sup 2} have been investigated by neutron spectroscopy. The irradiated targets generate neutrons through the reaction {sup 7}Li (p,n){sup 7}Be between accelerated protons and background {sup 7}Li ions inside the target. The produced neutron spectra observed from two different observation angles 20 deg. and 120 deg. to the target rear-side normal. From the measured and calculated spectra, by three-dimensional Monte Carlo code, the maximum energy, the total number, and the slope temperature of the accelerated ions are investigated. The results indicate that ions are not only accelerated from the front surface toward the rear surface, but also from the rear surface toward the front surface with comparable maximum energy and higher number.

  4. Calculations of neutron shielding data for 10-100 MeV proton accelerators.

    PubMed

    Chen, C C; Sheu, R J; Jian, S H

    2005-01-01

    The characteristics of neutron sources and their attenuation in concrete were investigated in detail for protons with energies ranging from 10 to 100 MeV striking on target materials of C, N, Al, Fe, Cu and W. A two-step approach was adopted: thick-target double-differential neutron yields were first calculated from the (p, xn) cross sections recommended in the ICRU Report 63; further, transport simulations of those neutrons in concrete were performed by using the FLUKA Monte Carlo code. The purpose of this study is to provide reasonably accurate parameters for shielding design for 10-100 MeV proton accelerators. Source terms and the corresponding attenuation lengths in concrete for several target materials are given as a function of proton energies and neutron emission angles. PMID:16604637

  5. Universality of the acceleration due to gravity on the surface of a rapidly rotating neutron star

    SciTech Connect

    AlGendy, Mohammad; Morsink, Sharon M.

    2014-08-20

    On the surface of a rapidly rotating neutron star, the effective centrifugal force decreases the effective acceleration due to gravity (as measured in the rotating frame) at the equator while increasing the acceleration at the poles due to the centrifugal flattening of the star into an oblate spheroid. We compute the effective gravitational acceleration for relativistic rapidly rotating neutron stars and show that for a star with mass M, equatorial radius R{sub e} , and angular velocity Ω, the deviations of the effective acceleration due to gravity from the nonrotating case take on a universal form that depends only on the compactness ratio M/R{sub e} , the dimensionless square of the angular velocity Ω{sup 2}R{sub e}{sup 3}/GM, and the latitude on the star's surface. This dependence is universal, in that it has very little dependence on the neutron star's equation of state. The effective gravity is expanded in the slow-rotation limit to show the dependence on the effective centrifugal force, oblate shape of the star, and the quadrupole moment of the gravitational field. In addition, an empirical fit and simple formula for the effective gravity is found. We find that the increase in the acceleration due to gravity at the poles is of the same order of magnitude as the decrease in the effective acceleration due to gravity at the equator for all realistic value of mass, radius, and spin. For neutron stars that spin with frequencies near 600 Hz, the difference between the effective gravity at the poles and the equator is about 20%.

  6. High-sensitivity transuranic waste assay by simultaneous proton and thermal-neutron interrogation using an electron linear accelerator

    SciTech Connect

    Franks, L.A.; Pigg, J.L.; Caldwell, J.T.; Cates, M.R.; Kunz, W.E.; Noel, B.W.

    1982-01-01

    Simultaneous photon and neutron interrogation from electron linear accelerator pulses is used as the basis for a unique assay technique for transuranics. Both prompt and delayed neutrons from the induced fissions are counted on a single detection system, and the contributions from each interrogating flux are resolved. Detection limits (3 sigma) for /sup 239/Pu were estimated to be 3 mg for prompt fission neutrons and 6 mg for delayed neutrons. The technique also provides a clear distinction between fissile and fertile nuclides.

  7. 9 GeV energy gain in a beam-driven plasma wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Litos, M.; Adli, E.; Allen, J. M.; An, W.; Clarke, C. I.; Corde, S.; Clayton, C. E.; Frederico, J.; Gessner, S. J.; Green, S. Z.; Hogan, M. J.; Joshi, C.; Lu, W.; Marsh, K. A.; Mori, W. B.; Schmeltz, M.; Vafaei-Najafabadi, N.; Yakimenko, V.

    2016-03-01

    An electron beam has gained a maximum energy of 9 GeV per particle in a 1.3 m-long electron beam-driven plasma wakefield accelerator. The amount of charge accelerated in the spectral peak was 28.3 pC, and the root-mean-square energy spread was 5.0%. The mean accelerated charge and energy gain per particle of the 215 shot data set was 115 pC and 5.3 GeV, respectively, corresponding to an acceleration gradient of 4.0 GeV m-1at the spectral peak. The mean energy spread of the data set was 5.1%. These results are consistent with the extrapolation of the previously reported energy gain results using a shorter, 36 cm-long plasma source to within 10%, evincing a non-evolving wake structure that can propagate distances of over a meter in length. Wake-loading effects were evident in the data through strong dependencies observed between various spectral properties and the amount of accelerated charge.

  8. 9 GeV energy gain in a beam-driven plasma wakefield accelerator

    DOE PAGESBeta

    Litos, M.; Adli, E.; Allen, J. M.; An, W.; Clarke, C. I.; Corde, S.; Clayton, C. E.; Frederico, J.; Gessner, S. J.; Green, S. Z.; et al

    2016-02-15

    An electron beam has gained a maximum energy of 9 GeV per particle in a 1.3 m-long electron beam-driven plasma wakefield accelerator. The amount of charge accelerated in the spectral peak was 28.3 pC, and the root-mean-square energy spread was 5.0%. The mean accelerated charge and energy gain per particle of the 215 shot data set was 115 pC and 5.3 GeV, respectively, corresponding to an acceleration gradient of 4.0 GeV m-1 at the spectral peak. Moreover, the mean energy spread of the data set was 5.1%. Our results are consistent with the extrapolation of the previously reported energy gainmore » results using a shorter, 36 cm-long plasma source to within 10%, evincing a non-evolving wake structure that can propagate distances of over a meter in length. Wake-loading effects were evident in the data through strong dependencies observed between various spectral properties and the amount of accelerated charge.« less

  9. Towards optical polarization control of laser-driven proton acceleration in foils undergoing relativistic transparency.

    PubMed

    Gonzalez-Izquierdo, Bruno; King, Martin; Gray, Ross J; Wilson, Robbie; Dance, Rachel J; Powell, Haydn; Maclellan, David A; McCreadie, John; Butler, Nicholas M H; Hawkes, Steve; Green, James S; Murphy, Chris D; Stockhausen, Luca C; Carroll, David C; Booth, Nicola; Scott, Graeme G; Borghesi, Marco; Neely, David; McKenna, Paul

    2016-01-01

    Control of the collective response of plasma particles to intense laser light is intrinsic to relativistic optics, the development of compact laser-driven particle and radiation sources, as well as investigations of some laboratory astrophysics phenomena. We recently demonstrated that a relativistic plasma aperture produced in an ultra-thin foil at the focus of intense laser radiation can induce diffraction, enabling polarization-based control of the collective motion of plasma electrons. Here we show that under these conditions the electron dynamics are mapped into the beam of protons accelerated via strong charge-separation-induced electrostatic fields. It is demonstrated experimentally and numerically via 3D particle-in-cell simulations that the degree of ellipticity of the laser polarization strongly influences the spatial-intensity distribution of the beam of multi-MeV protons. The influence on both sheath-accelerated and radiation pressure-accelerated protons is investigated. This approach opens up a potential new route to control laser-driven ion sources. PMID:27624920

  10. YALINA facility a sub-critical Accelerator- Driven System (ADS) for nuclear energy research facility description and an overview of the research program (1997-2008).

    SciTech Connect

    Gohar, Y.; Smith, D. L.; Nuclear Engineering Division

    2010-04-28

    The YALINA facility is a zero-power, sub-critical assembly driven by a conventional neutron generator. It was conceived, constructed, and put into operation at the Radiation Physics and Chemistry Problems Institute of the National Academy of Sciences of Belarus located in Minsk-Sosny, Belarus. This facility was conceived for the purpose of investigating the static and dynamic neutronics properties of accelerator driven sub-critical systems, and to serve as a neutron source for investigating the properties of nuclear reactions, in particular transmutation reactions involving minor-actinide nuclei. This report provides a detailed description of this facility and documents the progress of research carried out there during a period of approximately a decade since the facility was conceived and built until the end of 2008. During its history of development and operation to date (1997-2008), the YALINA facility has hosted several foreign groups that worked with the resident staff as collaborators. The participation of Argonne National Laboratory in the YALINA research programs commenced in 2005. For obvious reasons, special emphasis is placed in this report on the work at YALINA facility that has involved Argonne's participation. Attention is given here to the experimental program at YALINA facility as well as to analytical investigations aimed at validating codes and computational procedures and at providing a better understanding of the physics and operational behavior of the YALINA facility in particular, and ADS systems in general, during the period 1997-2008.

  11. A non-hydrodynamical model for acceleration of line-driven winds in active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Risaliti, G.; Elvis, M.

    2010-06-01

    Context. Radiation driven winds are the likely origin of AGN outflows, and are believed to be a fundamental component of the inner structure of AGNs. Several hydrodynamical models have been developed, showing that these winds can be effectively launched from AGN accretion disks. Aims: Here we want to study the acceleration phase of line-driven winds in AGNs, in order to examine the physical conditions required for the existence of such winds for a wide variety of initial conditions. Methods: We built a simple and fast non-hydrodynamic model QWIND, where we assume that a wind is launched from the accretion disk at supersonic velocities of a few 100 km s-1, and we concentrated on the subsequent supersonic phase, when the wind is accelerated to final velocities up to 104 km s-1. Results: We show that, with a set of initial parameters in agreement with observations in AGNs, this model can produce a wind with terminal velocities on the order of 104 km s-1. There are three zones in the wind, only the middle one of which can launch a wind: in the inner zone the wind is too ionized and so experiences only the Compton radiation force, which is not effective in accelerating gas. This inner “failed wind” is important for shielding the next zone by lowering the ionization parameter there. In the middle zone the lower ionization of the gas leads to a much larger radiation force and the gas achieves escape velocity This middle zone is quite thin (about 100 gravitational radii). The outer, third zone is shielded from the UV radiation by the central wind zone, so does not achieve a high enough acceleration to reach escape velocity. We also describe a simple analytic approximation of our model, in which we neglect the effects of gravity during the acceleration phase. This analytic approach agrees with the results of the numerical code, and is a powerful way to check whether a radiation driven wind can be accelerated with a given set of initial parameters. Conclusions: Our

  12. Blast Wave Formation by Laser-Sustained Nonequilibrium Plasma in the Laser-Driven In-Tube Accelerator Operation

    SciTech Connect

    Ogino, Yousuke; Ohnishi, Naofumi; Sawada, Keisuke; Sasoh, Akihiro

    2006-05-02

    Understanding the dynamics of laser-produced plasma is essentially important for increasing available thrust force in a gas-driven laser propulsion system such as laser-driven in-tube accelerator. A computer code is developed to explore the formation of expanding nonequilibrium plasma produced by laser irradiation. Various properties of the blast wave driven by the nonequilibrium plasma are examined. It is found that the blast wave propagation is substantially affected by radiative cooling effect for lower density case.

  13. Neutron dose calculation at the maze entrance of medical linear accelerator rooms.

    PubMed

    Falcão, R C; Facure, A; Silva, A X

    2007-01-01

    Currently, teletherapy machines of cobalt and caesium are being replaced by linear accelerators. The maximum photon energy in these machines can vary from 4 to 25 MeV, and one of the great advantages of these equipments is that they do not have a radioactive source incorporated. High-energy (E > 10 MV) medical linear accelerators offer several physical advantages over lower energy ones: the skin dose is lower, the beam is more penetrating, and the scattered dose to tissues outside the target volume is smaller. Nevertheless, the contamination of undesirable neutrons in the therapeutic beam, generated by the high-energy photons, has become an additional problem as long as patient protection and occupational doses are concerned. The treatment room walls are shielded to attenuate the primary and secondary X-ray fluence, and this shielding is generally adequate to attenuate the neutrons. However, these neutrons are scattered through the treatment room maze and may result in a radiological problem at the door entrance, a high occupancy area in a radiotherapy facility. In this article, we used MCNP Monte Carlo simulation to calculate neutron doses in the maze of radiotherapy rooms and we suggest an alternative method to the Kersey semi-empirical model of neutron dose calculation at the entrance of mazes. It was found that this new method fits better measured values found in literature, as well as our Monte Carlo simulated ones. PMID:17005540

  14. Measurements of Accelerator-Produced Leakage Neutron and Photon Transmission through Concrete

    SciTech Connect

    Nelson, Walter R

    2002-07-04

    Optimum shielding of the radiation from particle accelerators requires knowledge of the attenuation characteristics of the shielding material. The most common material for shielding this radiation is concrete, which can be made using various materials of different densities as aggregates. These different concrete mixes can have very different attenuation characteristics. Information about the attenuation of leakage photons and neutrons in ordinary and heavy concrete is, however, very limited. To increase our knowledge and understanding of the radiation attenuation in concrete of various compositions, we have performed measurements of the transmission of leakage radiation, photons and neutrons, from a Varian Clinac 2100C medical linear accelerator operating at maximum electron energies of 6 and 18 MeV. We also calculated, using Monte Carlo techniques, the leakage neutron spectra and its transmission through concrete. The results of these measurements and calculations extend the information currently available for designing shielding for medical electron accelerators. Photon transmission characteristics depend more on the manufacturer of the concrete than on the atomic composition. A possible cause for this effect is a non-uniform distribution of the high density aggregate, typically iron, in the concrete matrix. Errors in estimated transmission of photons can exceed a factor of three, depending on barrier thickness, if attenuation in high-density concrete is simply scaled from that of normal density concrete. We found that neutron transmission through the high-density concretes can be estimated most reasonably and conservatively by using the linear tenth-value layer of normal concrete if specific values of the tenth-value layer of the high-density concrete are not known. The reason for this is that the neutron transmission depends primarily on the hydrogen content of the concrete, which does not significantly depend on concrete density. Errors of factors of two to

  15. Invited Review Article: "Hands-on" laser-driven ion acceleration: A primer for laser-driven source development and potential applications

    NASA Astrophysics Data System (ADS)

    Schreiber, J.; Bolton, P. R.; Parodi, K.

    2016-07-01

    An overview of progress and typical yields from intense laser-plasma acceleration of ions is presented. The evolution of laser-driven ion acceleration at relativistic intensities ushers prospects for improved functionality and diverse applications which can represent a varied assortment of ion beam requirements. This mandates the development of the integrated laser-driven ion accelerator system, the multiple components of which are described. Relevant high field laser-plasma science and design of controlled optimum pulsed laser irradiation on target are dominant single shot (pulse) considerations with aspects that are appropriate to the emerging petawatt era. The pulse energy scaling of maximum ion energies and typical differential spectra obtained over the past two decades provide guidance for continued advancement of laser-driven energetic ion sources and their meaningful applications.

  16. Ultraviolet radiation accelerates BRAF-driven melanomagenesis by targeting TP53

    PubMed Central

    Rae, Joel; Hogan, Kate; Ejiama, Sarah; Girotti, Maria Romina; Cook, Martin; Dhomen, Nathalie; Marais, Richard

    2014-01-01

    Cutaneous melanoma is epidemiologically linked to ultraviolet radiation (UVR), but the molecular mechanisms by which UVR drives melanomagenesis remain unclear1,2. The most common somatic mutation in melanoma is a V600E substitution in BRAF, which is an early event3. To investigate how UVR accelerates oncogenic BRAF-driven melanomagenesis, we used a V600EBRAF mouse model. In mice expressing V600EBRAF in their melanocytes, a single dose of UVR that mimicked mild sunburn in humans induced clonal expansion of the melanocytes, and repeated doses of UVR increased melanoma burden. We show that sunscreen (UVA superior: UVB SPF50) delayed the onset of UVR-driven melanoma, but only provided partial protection. The UVR-exposed tumours presented increased numbers of single nucleotide variants (SNVs) and we observed mutations (H39Y, S124F, R245C, R270C, C272G) in the Trp53 tumour suppressor in ~40% of cases. TP53 is an accepted UVR target in non-melanoma skin cancer, but is not thought to play a major role in melanoma4. However, we show that mutant Trp53 accelerated V600EBRAF-driven melanomagenesis and that TP53 mutations are linked to evidence of UVR-induced DNA damage in human melanoma. Thus, we provide mechanistic insight into epidemiological data linking UVR to acquired naevi in humans5. We identify TP53/Trp53 as a UVR-target gene that cooperates with V600EBRAF to induce melanoma, providing molecular insight into how UVR accelerates melanomagenesis. Our study validates public health campaigns that promote sunscreen protection for individuals at risk of melanoma. PMID:24919155

  17. Measurements of Neutron Induced Cross Sections at the Oak Ridge Electron Linear Accelerator

    SciTech Connect

    Guber, K.H.; Harvey, J.A.; Hill, N.W.; Koehler, P.E.; Leal, L.C.; Sayer, R.O.; Spencer, R.R.

    1999-09-20

    We have used the Oak Ridge Electron Linear Accelerator (ORELA) to measure neutron total and the fission cross sections of 233U in the energy range from 0.36 eV to ~700 keV. We report average fission and total cross sections. Also, we measured the neutron total cross sections of 27Al and Natural chlorine as well as the capture cross section of Al over an energy range from 100 eV up to about 400 keV.

  18. Additive effect of BPA and Gd-DTPA for application in accelerator-based neutron source.

    PubMed

    Yoshida, F; Yamamoto, T; Nakai, K; Zaboronok, A; Matsumura, A

    2015-12-01

    Because of its fast metabolism gadolinium as a commercial drug was not considered to be suitable for neutron capture therapy. We studied additive effect of gadolinium and boron co-administration using colony forming assay. As a result, the survival of tumor cells with additional 5 ppm of Gd-DTPA decreased to 1/10 compared to the cells with boron only. Using gadolinium to increase the effect of BNCT instead of additional X-ray irradiation might be beneficial, as such combination complies with the short-time irradiation regimen at the accelerator-based neutron source. PMID:26242560

  19. Freezing, accelerating, and slowing directed currents in real time with superimposed driven lattices

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Aritra K.; Liebchen, Benno; Wulf, Thomas; Schmelcher, Peter

    2016-05-01

    We provide a generic scheme offering real-time control of directed particle transport using superimposed driven lattices. This scheme allows one to accelerate, slow, and freeze the transport on demand by switching one of the lattices subsequently on and off. The underlying physical mechanism hinges on a systematic opening and closing of channels between transporting and nontransporting phase space structures upon switching and exploits cantori structures which generate memory effects in the population of these structures. Our results should allow for real-time control of cold thermal atomic ensembles in optical lattices but might also be useful as a design principle for targeted delivery of molecules or colloids in optical devices.

  20. Vacuum electron acceleration driven by a tightly focused radially polarized Gaussian beam.

    PubMed

    Dai, Lin; Li, Jian-Xing; Zang, Wei-Ping; Tian, Jian-Guo

    2011-05-01

    Electron acceleration in vacuum driven by a tightly focused radially polarized Gaussian beam has been studied in detail. Weniger transformation method is used to eliminate the divergence of the radially polarized electromagnetic field derived from the Lax series approach. And, electron dynamics in an intense radially polarized Gaussian beam is analyzed by using the Weniger transformation field. The roles of the initial phase of the electromagnetic field and the injection angle, position and energy of electron in energy gain of electron have been studied in detail. PMID:21643185

  1. Conceptual configurations of an accelerator-driven subcritical system utilizing minor actinides

    SciTech Connect

    Cao, Y.; Gohar, Y.

    2012-07-01

    This paper purposes an Accelerator-Driven Subcritical (ADS) system which utilizes the Minor Actinides (MAs) from the US spent nuclear fuel inventory. A mobile fuel concept with micro-particles suspended in the liquid metal is adopted in the purposed system to avoid difficulties of developing and testing new MAs solid fuel forms. Three ADS configurations were developed and analyzed using the Monte Carlo fuel burnup methodology. The analyses demonstrated the capabilities of the proposed system to utilize the MAs and to dispose of the US spent nuclear fuels. (authors)

  2. Numerical Simulation of Laser-driven In-Tube Accelerator on Supersonic Condition

    SciTech Connect

    Kim, Sukyum; Jeung, In-Seuck; Choi, Jeong-Yeol

    2004-03-30

    Recently, several laser propulsion vehicles have been launched successfully. But these vehicles remained in a very low subsonic flight. Laser-driven In-Tube Accelerator (LITA) is developed as unique laser propulsion system at Tohoku University. In this paper, flow characteristics and momentum coupling coefficients are studied numerically in the supersonic condition with the same configuration of LITA. Because of the aerodynamic drag, the coupling coefficient could not get correctly especially at the low energy input. In this study, the coupling coefficient was calculated using the concept of the effective impulse.

  3. Numerical Simulation of Laser-driven In-Tube Accelerator on Supersonic Condition

    NASA Astrophysics Data System (ADS)

    Kim, Sukyum; Jeung, In-Seuck; Choi, Jeong-Yeol

    2004-03-01

    Recently, several laser propulsion vehicles have been launched successfully. But these vehicles remained in a very low subsonic flight. Laser-driven In-Tube Accelerator (LITA) is developed as unique laser propulsion system at Tohoku University. In this paper, flow characteristics and momentum coupling coefficients are studied numerically in the supersonic condition with the same configuration of LITA. Because of the aerodynamic drag, the coupling coefficient could not get correctly especially at the low energy input. In this study, the coupling coefficient was calculated using the concept of the effective impulse.

  4. Proposed method for high-speed plasma density measurement in proton-driven plasma wakefield acceleration

    SciTech Connect

    Tarkeshian, R.; Reimann, O.; Muggli, P.

    2012-12-21

    Recently a proton-bunch-driven plasma wakefield acceleration experiment using the CERN-SPS beam was proposed. Different types of plasma cells are under study, especially laser ionization, plasma discharge, and helicon sources. One of the key parameters is the spatial uniformity of the plasma density profile along the cell that has to be within < 1% of the nominal density (6 Multiplication-Sign 10{sup 14} cm{sup -3}). Here a setup based on a photomixing concept is proposed to measure the plasma cut-off frequency and determine the plasma density.

  5. Modeling laser-driven electron acceleration using WARP with Fourier decomposition

    NASA Astrophysics Data System (ADS)

    Lee, P.; Audet, T. L.; Lehe, R.; Vay, J.-L.; Maynard, G.; Cros, B.

    2016-09-01

    WARP is used with the recent implementation of the Fourier decomposition algorithm to model laser-driven electron acceleration in plasmas. Simulations were carried out to analyze the experimental results obtained on ionization-induced injection in a gas cell. The simulated results are in good agreement with the experimental ones, confirming the ability of the code to take into account the physics of electron injection and reduce calculation time. We present a detailed analysis of the laser propagation, the plasma wave generation and the electron beam dynamics.

  6. Chemistry technology base and fuel cycle of the Los Alamos accelerator-driven transmutation system

    SciTech Connect

    Williamson, M.A.

    1997-12-01

    This paper provides a brief overview of the Los Alamos accelerator-driven transmutation system, a description of the pyrochemistry technology base and the fuel cycle for the system. The pyrochemistry technology base consists of four processes: direct oxide reduction, reductive extraction, electrorefining, and electrowinning. Each process and its utility is described. The fuel cycle is described for a liquid metal-based system with the focus being the conversion of commercial spent nuclear fuel to fuel for the transmutation system. Fission product separation and actinide recycle processes are also described.

  7. Neutron-induced electronic failures around a high-energy linear accelerator

    SciTech Connect

    Kry, Stephen F.; Johnson, Jennifer L.; White, R. Allen; Howell, Rebecca M.; Kudchadker, Rajat J.; Gillin, Michael T.

    2011-01-15

    Purpose: After a new in-vault CT-on-rails system repeatedly malfunctioned following use of a high-energy radiotherapy beam, we investigated the presence and impact of neutron radiation on this electronic system, as well as neutron shielding options. Methods: We first determined the CT scanner's failure rate as a function of the number of 18 MV monitor units (MUs) delivered. We then re-examined the failure rate with both 2.7-cm-thick and 7.6-cm-thick borated polyethylene (BPE) covering the linac head for neutron shielding. To further examine shielding options, as well as to explore which neutrons were relevant to the scanner failure, Monte Carlo simulations were used to calculate the neutron fluence and spectrum in the bore of the CT scanner. Simulations included BPE covering the CT scanner itself as well as covering the linac head. Results: We found that the CT scanner had a 57% chance of failure after the delivery of 200 MUs. While the addition of neutron shielding to the accelerator head reduced this risk of failure, the benefit was minimal and even 7.6 cm of BPE was still associated with a 29% chance of failure after the delivery of 200 MU. This shielding benefit was achieved regardless of whether the linac head or CT scanner was shielded. Additionally, it was determined that fast neutrons were primarily responsible for the electronic failures. Conclusions: As illustrated by the CT-on-rails system in the current study, physicists should be aware that electronic systems may be highly sensitive to neutron radiation. Medical physicists should therefore monitor electronic systems that have not been evaluated for potential neutron sensitivity. This is particularly relevant as electronics are increasingly common in the therapy vault and newer electronic systems may exhibit increased sensitivity.

  8. Acceleration of laser-driven ion bunch from double-layer thin foils

    SciTech Connect

    Wang, X.; Liang, E.; Yu, W.; Yu, M. Y.

    2012-05-15

    Generation of monoenergetic ion bunch from a double-layer thin-foil target irradiated by an intense linearly polarized laser pulse is investigated using two-dimensional particle-in-cell simulation. The protons in the front low-density hydrogen target layer accelerated by the space-charge field of the laser-driven hot electrons can penetrate through the high-Z high-mass and high-density ion layer, resulting in an energetic proton bunch. A part of the latter is further accelerated by the space-charge field of the hot electrons in the vacuum behind the high-Z ion layer. With this scheme, quasi-monoenergetic proton bunches can be produced using presently available laser pulses of moderate contrast and duration.

  9. Influence of radiation reaction force on ultraintense laser-driven ion acceleration.

    PubMed

    Capdessus, R; McKenna, P

    2015-05-01

    The role of the radiation reaction force in ultraintense laser-driven ion acceleration is investigated. For laser intensities ∼10(23)W/cm(2), the action of this force on electrons is demonstrated in relativistic particle-in-cell simulations to significantly enhance the energy transfer to ions in relativistically transparent targets, but strongly reduce the ion energy in dense plasma targets. An expression is derived for the revised piston velocity, and hence ion energy, taking account of energy loses to synchrotron radiation generated by electrons accelerated in the laser field. Ion mass is demonstrated to be important by comparing results obtained with proton and deuteron plasma. The results can be verified in experiments with cryogenic hydrogen and deuterium targets. PMID:26066270

  10. Feasibility of an XUV FEL Oscillator Driven by a SCRF Linear Accelerator

    SciTech Connect

    Lumpkin, A. H.; Freund, H. P.; Reinsch, M.

    2014-01-01

    The Advanced Superconducting Test Accelerator (ASTA) facility is currently under construction at Fermi National Accelerator Laboratory. Using a1-ms-long macropulse composed of up to 3000 micropulses, and with beam energies projected from 45 to 800 MeV, the possibility for an extreme ultraviolet (XUV) free-electron laser oscillator (FELO) with the higher energy is evaluated. We have used both GINGER with an oscillator module and the MEDUSA/OPC code to assess FELO saturation prospects at 120 nm, 40 nm, and 13.4 nm. The results support saturation at all of these wavelengths which are also shorter than the demonstrated shortest wavelength record of 176 nm from a storage-ring-based FELO. This indicates linac-driven FELOs can be extended into this XUV wavelength regime previously only reached with single-pass FEL configurations.

  11. New methods for high current fast ion beam production by laser-driven acceleration

    SciTech Connect

    Margarone, D.; Krasa, J.; Prokupek, J.; Velyhan, A.; Laska, L.; Jungwirth, K.; Mocek, T.; Korn, G.; Rus, B.; Torrisi, L.; Gammino, S.; Cirrone, P.; Cutroneo, M.; Romano, F.; Picciotto, A.; Serra, E.; Giuffrida, L.; Mangione, A.; Rosinski, M.; Parys, P.; and others

    2012-02-15

    An overview of the last experimental campaigns on laser-driven ion acceleration performed at the PALS facility in Prague is given. Both the 2 TW, sub-nanosecond iodine laser system and the 20 TW, femtosecond Ti:sapphire laser, recently installed at PALS, are used along our experiments performed in the intensity range 10{sup 16}-10{sup 19} W/cm{sup 2}. The main goal of our studies was to generate high energy, high current ion streams at relatively low laser intensities. The discussed experimental investigations show promising results in terms of maximum ion energy and current density, which make the laser-accelerated ion beams a candidate for new-generation ion sources to be employed in medicine, nuclear physics, matter physics, and industry.

  12. Electron self-injection in the proton-driven-plasma-wakefield acceleration

    SciTech Connect

    Hu, Zhang-Hu; Wang, You-Nian

    2013-12-15

    The self-injection process of plasma electrons in the proton-driven-plasma-wakefield acceleration scheme is investigated using a two-dimensional, electromagnetic particle-in-cell method. Plasma electrons are self-injected into the back of the first acceleration bucket during the initial bubble formation period, where the wake phase velocity is low enough to trap sufficient electrons. Most of the self-injected electrons are initially located within a distance of the skin depth c/ω{sub pe} to the beam axis. A decrease (or increase) in the beam radius (or length) leads to a significant reduction in the total charges of self-injected electron bunch. Compared to the uniform plasma, the energy spread, emittance and total charges of the self-injected bunch are reduced in the plasma channel case, due to a reduced injection of plasma electrons that initially located further away from the beam axis.

  13. A Fast, Electromagnetically Driven Supersonic Gas Jet Target For Laser Wakefield Acceleration

    SciTech Connect

    Krishnan, Mahadevan; Wright, Jason; Ma, Timothy

    2009-01-22

    Laser-Wakefield acceleration (LWFA) promises electron accelerators with unprecedented electric field gradients. Gas jets and gas-filled capillary discharge waveguides are two primary targets of choice for LWFA. Present gas jets have lengths of only 2-4 mm at densities of 1-4x10{sup 19} /cm{sup 3}, sufficient for self-trapping and acceleration to energies up to {approx}150 MeV. While 3 cm capillary structures have been used to accelerate beams up to 1 GeV, gas jets require a well-collimated beam that is {>=}10 mm in length and <500 {mu}m in width, with a tunable gas density profile to optimize the LWFA process. This paper describes the design of an electromagnetically driven, fast supersonic gas valve that opens in <100 {mu}s, closes in <500 {mu}s and can operate at pressures beyond 1000 psia. The motion of the valve seat (flyer plate) is measured using a laser probe and compared with predictions of a model. The valve design is based on an optimization of many parameters: flyer plate mass and durability, driver bank speed and stored energy for high rep-rate (>10 Hz) operation, return spring non-linearity and materials selection for various components. Optimization of the valve dynamics and preliminary designs of the supersonic flow patterns are described.

  14. Design of a subcritical multiplying low-enriched uranium externally driven neutron assembly at the Los Alamos neutron science center

    SciTech Connect

    Gavron, Victor

    2008-01-01

    The Sandia Pulsed Reactor (SPR) has had a long history of supplying short intense neutron bursts to test the survivability of critical weapons components. The most recent version, SPR III, was resurrected in 2005 in support of critical survivability testing for W-76 Life Extension Program and other testing for the Qualification Alternatives to SPR program. SPR has now been decommissioned. The SPR had a cylindrical shape, with an internal cylindrical cavity where samples were placed for testing. The approximate dimensions of the cavity were 16.5 cm radius, and 38.1 cm high. The uniformity of the fluence over the entire volume was {+-} 25%. The nominal fluence was 5.4 {center_dot} 10{sup 14} n/cm{sup 2}, 1 MeV Si equivalent (Si equivalent implies that the neutron spectrum, at energies other than 1 MeV, is weighted by its relative damage potential in silicon), with a pulse duration of 55 microseconds, FWHM. We propose a new facility as a replacement to the SPR pulsed neutron capabilities, utilizing the proton linear accelerator at the Los Alamos Neutron Science Center (LANSCE). Currently, LANSCE provides neutron beams generated by the 800 MeV proton beam, over 13 decades of energy, to five different facilities. LANSCE is in the process of being refurbished; the refurbishment project (LANSCE-R) is funded and due to be completed by 2014. In parallel to the refurbishment, the experimental user program will continue and provide 3000 hours of beam per year. LANSCE is also considering upgrade options in the framework of MaRIE (Materials and Radiation Interactions in Extreme). MaRIE is planned to be the new signature facility for Los Alamos for the foreseeable future. Hence, they expect LANSCE to continue to operate and provide beams for decades t come. They propose to use the 800 MeV proton beam, extracted from the Proton Storage Ring (PSR), to initiate a neutron pulse in a sub-critical multiplying assembly, fabricated from Low-Enriched Uranium (LEU). The reason for using

  15. Deuteron Acceleration and Fusion Neutron Production in Z-pinch plasmas

    SciTech Connect

    Klir, D.; Kravarik, J.; Kubes, P.; Rezac, K.; Ananeev, S. S.; Bakshaev, Yu. L.; Blinov, P. I.; Chernenko, A. S.; Kazakov, E. D.; Korolev, V. D.; Ustroev, G. I.

    2009-01-21

    Fusion neutron measurements were carried out on the S-300 generator (Kurchatov Institute, Moscow). We tried deuterated fibers, various types of wire arrays imploding onto a deuterated fiber, and deuterium gas puffs as Z-pinch loads. On the current level of 2 MA, the peak neutron yield of 10{sup 10} was achieved with a deuterium gas-puff. The neutron and deuteron energy spectra were quite similar in various types of Z-pinch configurations. The broad width of radial neutron spectra implied a high radial component of deuteron velocity. On the basis of neutron measurements, we concluded that neutron production mechanism is connected with the study of plasma voltage. It means that the acceleration of fast deuterons is not a secondary process but it reflects the global dynamics of Z-pinch plasmas. For this reason it is useful to add deuterium as a 'tracer' in Z-pinch loads more often. For instance, it seems attractive to prepare wire-arrays from deuterated metal wires such as Pd.

  16. Evaluation of neutron dose in the maze of medical electron accelerators.

    PubMed

    Carinou, E; Kamenopoulou, V; Stamatelatos, I E

    1999-12-01

    MCNP code was used to simulate neutron and prompt gamma ray transport for a range of maze geometrical parameters, wall composition, and wall surface lining. Verification measurements were performed at two medical electron accelerator facilities. A very good agreement was observed between the results of the measurements and the MCNP simulation. MCNP code results were compared with the results of analytical equations used for the calculation of maze effectiveness, derived by Kersey and McCall. A good agreement exists between the simulation results and the results of the analytical methods for maze lengths longer than 8.5 m. However, the results of the present study showed that for shorter maze lengths, Kersey's method tended to overestimate neutron dose at the door entrance, whereas McCall's method with the neutron room scattered correction applied, showed an underestimation of neutron dose. Furthermore, according to MCNP simulation results, the use of barytes concrete instead of standard concrete as room shielding material, reduced neutron dose at the door entrance by about 20%. Finally, it was shown that lining with layers of wood and borated polyethylene significantly reduced the neutron dose at the door entrance by 45% and 65%, respectively. PMID:10619233

  17. Use of accelerator mass spectrometry in the dosimetry of Hiroshima neutrons

    NASA Astrophysics Data System (ADS)

    Straume, T.; Finkel, R. C.; Eddy, D.; Kubik, P. W.; Gove, H. E.; Sharma, P.; Fujita, S.; Hoshi, M.

    1990-12-01

    A substantial discrepancy exists between the measured values for thermal neutron activation and the values calculated using the new A-bomb dosimetry system, DS86. As part of a joint US-Japan effort aimed at resolving this discrepancy, we have shown that 36Cl/Cl in mineral samples (i.e., concrete, granite, tiles) can be measured with sufficient precision using accelerator mass spectrometry (AMS) to quantify the very low thermal neutron activation levels at distances between 1000 and 2000 m from the hypocenter in Hiroshima. Our initial measurement results show that activation of Cl by the bomb neutrons disagree with calculations based on the new DS86 dosimetry system (measurements of 36Cl at 1450 m from the hypocenter indicate thermal neutron activation that is ˜15 times higher than obtained from DS86 calculations; discrepancies are even larger at 1606 m). This is a preliminary report of work in progress. The principal objectives of this work are to reconstruct the thermal neutron fluence as a function of distance from the hypocenters in both Hiroshima and Nagasaki using 36Cl/Cl and obtain information about fast neutron fluence.

  18. Neutron Induced Reactions with the 17 Mev Facility at the Athens Tandem Accelerator NCSR 'Demokritos'

    NASA Astrophysics Data System (ADS)

    Vlastou, R.; Kalamara, A.; Serris, M.; Diakaki, M.; Kokkoris, M.; Paneta, V.; Axiotis, M.; Lagoyannis, A.

    In the 5.5 MV tandem T11/25 Accelerator Laboratory of NCSR "Demokritos" monoenergetic neutron beams have been produced in the energy range∼ 15-20 MeV using anew Ti-tritiated target of 373 GBq activity, by means of the 3H(d,n)4He reaction. The corresponding deuteron beam energies obtained from the accelerator, were in the 1.5-4.5MeV range.The maximum flux has been determined to be of the order of 106 n/cm2 s, implementing reference reactions. The 17.1MeV neutron beam has been used for the measurement of 197Au(n,2n) reaction cross section. Theoretical calculations have been performed via the statistical model code EMPIRE and compared to the experimental data of the present work and data from literature.

  19. Nonlinear development of strong current-driven instabilities and selective acceleration of ^3He ions

    NASA Astrophysics Data System (ADS)

    Toida, Mieko; Okumura, Hayato

    2003-10-01

    In some solar flares, the abundance of high-energy ^3He ions is extremely increased. As a mechanism for these ^3He rich events, current-driven instabilities are believed to be important. Nonlinear development of the strong current-driven instabilities and associated energy transfer to ^3He ions are studied theoretically and numerically [1]. First, by means of a two-dimensional, electrostatic, particle simulation code, it is demonstrated that ^3He ions are selectively accelerated by fundamental H cyclotron waves with frequencies ω ≃ 2Ω_3He (Ω_3He is the cyclotron frequency of ^3He). Then, from the analysis of the dispersion relation of these waves, it is found that the ω ≃ 2 Ω_ 3He waves have the greatest growth rate, if Te > 10 T_H. Energies of the ^3He ions are also discussed. Theoretical expression for the maximum ^3He energy is presented, which is in good agreement with the simulation results. Based on this theory, it is shown that when the initial electron drift energy is of the order of 10 keV, many ^3He ions can be accelerated to energies of the order of MeV/n. [1] M. Toida and H. Okumura, J. Phys. Soc. Jpn. 72,1098 (2003)

  20. Radiation reaction effect on laser driven auto-resonant particle acceleration

    SciTech Connect

    Sagar, Vikram; Sengupta, Sudip; Kaw, P. K.

    2015-12-15

    The effects of radiation reaction force on laser driven auto-resonant particle acceleration scheme are studied using Landau-Lifshitz equation of motion. These studies are carried out for both linear and circularly polarized laser fields in the presence of static axial magnetic field. From the parametric study, a radiation reaction dominated region has been identified in which the particle dynamics is greatly effected by this force. In the radiation reaction dominated region, the two significant effects on particle dynamics are seen, viz., (1) saturation in energy gain by the initially resonant particle and (2) net energy gain by an initially non-resonant particle which is caused due to resonance broadening. It has been further shown that with the relaxation of resonance condition and with optimum choice of parameters, this scheme may become competitive with the other present-day laser driven particle acceleration schemes. The quantum corrections to the Landau-Lifshitz equation of motion have also been taken into account. The difference in the energy gain estimates of the particle by the quantum corrected and classical Landau-Lifshitz equation is found to be insignificant for the present day as well as upcoming laser facilities.

  1. Collisionless shocks and particle acceleration in laser-driven laboratory plasmas

    NASA Astrophysics Data System (ADS)

    Fiuza, Frederico

    2012-10-01

    Collisionless shocks are pervasive in space and astrophysical plasmas, from the Earth's bow shock to Gamma Ray Bursters; however, the microphysics underlying shock formation and particle acceleration in these distant sites is not yet fully understood. Mimicking these extreme conditions in laboratory is a grand challenge that would allow for a better understanding of the physical processes involved. Using ab initio multi-dimensional particle-in-cell simulations, shock formation and particle acceleration are investigated for realistic laboratory conditions associated with the interaction of intense lasers with high-energy-density plasmas. Weibel-instability-mediated shocks are shown to be driven by the interaction of an ultraintense laser with overcritical plasmas. In this piston regime, the laser generates a relativistic flow that is Weibel unstable. The strong Weibel magnetic fields deflect the incoming flow, compressing it, and forming a shock. The resulting shock structure is consistent with previous simulations of relativistic astrophysical shocks, demonstrating for the first time the possibility of recreating these structures in laboratory. As the laser intensity is decreased and near-critical density plasmas are used, electron heating dominates over radiation pressure and electrostatic shocks can be formed. The electric field associated with the shock front can reflect ions from the background accelerating them to high energies. It is shown that high quality 200 MeV proton beams, required for tumor therapy, can be generated by using an exponentially decaying plasma profile to control competing accelerating fields. These results pave the way for the experimental exploration of space and astrophysical relevant shocks and particle acceleration with current laser systems.

  2. Production of 64Cu and 67Cu radiopharmaceuticals using zinc target irradiated with accelerator neutrons

    NASA Astrophysics Data System (ADS)

    Kawabata, Masako; Hashimoto, Kazuyuki; Saeki, Hideya; Sato, Nozomi; Motoishi, Shoji; Nagai, Yasuki

    2014-09-01

    Copper radioisotopes have gained a lot of attention in radiopharmaceuticals owing to their unique decay characteristics. The longest half-life β emitter, 67Cu, is thought to be suitable for targeted radio-immunotherapy. Adequate production of 67Cu to meet the demands of clinical studies has not been fully established. Another attractive copper isotope, 64Cu has possible applications as a diagnostic imaging tracer combined with a therapeutic effect. This work proposes a production method using accelerator neutrons in which two copper radioisotopes can be produced: 1) 68Zn(n,x)67Cu and 2) 64Zn(n,p)64Cu using ~14 MeV neutrons generated by natC(d, n) reaction, both from natural or enriched zinc oxides. The generated 64,67Cu were separated from the target zinc oxide using a chelating and an anion exchange columns and were labelled with two widely studied chelators where the labelling efficiency was found to be acceptably good. The major advantage of this method is that a significant amount of 64,67Cu with a very few impurity radionuclides are produced which also makes the separation procedure simple. Provided an accelerator supplying an Ed = ~ 40 MeV, a wide application of 64,67Cu based drugs in nuclear medicine is feasible in the near future. We will present the characteristics of this production method using accelerator neutrons including the chemical separation processes.

  3. An epithermal neutron source for BNCT based on an ESQ-accelerator

    SciTech Connect

    Ludewigt, B.A.; Chu, W.T.; Donahue, R.J.; Kwan, J.; Phillips, T.L.; Reginato, L.L.; Wells, R.P.

    1997-07-01

    An accelerator-based BNCT facility is under development at the Lawrence Berkeley National Laboratory. Neutrons will be produced via the {sup 7}Li(p,n) reaction at proton energies of about 2.5 MeV with subsequent moderation and filtering for shaping epithermal neutron beams for BNCT. Moderator, filter, and shielding assemblies have been modeled using MCNP. Head-phantom dose distributions have been calculated using the treatment planning software BNCT{_}RTPE. The simulation studies have shown that a proton beam current of {approximately} 20 mA is required to deliver high quality brain treatments in about 40 minutes. The results also indicate that significantly higher doses can be delivered to deep-seated tumors in comparison to the Brookhaven Medical Research Reactor beam. An electrostatic quadrupole (ESQ) accelerator is ideally suited to provide the high beam currents desired. A novel power supply utilizing the air-coupled transformer concept is under development. It will enable the ESQ-accelerator to deliver proton beam currents exceeding 50 mA. A lithium target has been designed which consists of a thin layer of lithium on an aluminum backing. Closely spaced, narrow coolant passages cut into the aluminum allow the removal of a 50kW heat-load by convective water cooling. The system under development is suitable for hospital installation and has the potential for providing neutron beams superior to reactor sources.

  4. Neutron dosimetry in linear electron accelerator during radiotherapy treatment: simulation and experiment

    NASA Astrophysics Data System (ADS)

    Manfredotti, Claudio; Nastasi, U.; Ongaro, C.; Stasi, E.; Zanini, Alessandro

    1995-03-01

    In the electron linear accelerators used for radiotherapy by high energy electrons or gamma rays, there is a non negligible production of neutrons by photodisintegration or electrodisintegration reactions on the high Z components of the head machine (target, flattening filter, collimators). At the Experimental Physics Department of Torino University, Torino, Italy an experimental and theoretical evaluation has been performed on the undesired neutron production in the MD Class Mevatron Siemens accelerator used at the Radiotherapy Department of S. Giovanni Battista A.S. Hospital for cancer therapy by a 15 MV gamma ray beam. A simulation of the total process has been carried out, using EGS4 MonteCarlo computer code for the evaluation of photoneutron spectra and MCNP code for the neutron transport in the patient's body. The geometrical description both of the accelerator head in EGS4 and of the anthropomorphous phantom in MCNP have been highly optimized. Experimental measurements have been carried out by bubble detectors BD 100R appropriately allocated inside a new phantom in polyetylene and plexiglass, especially designed for this purpose.

  5. A Data-Driven Analytical Model for Proton Acceleration at Remotely Observed Low Coronal Shocks

    NASA Astrophysics Data System (ADS)

    Kozarev, Kamen; Schwadron, Nathan

    2016-04-01

    We have recently studied the development of a large-scale off-limb coronal bright front (OCBF) low in the solar corona (Kozarev et al., 2015), by using remote observations from the Solar Dynamics Observatory's Advanced Imaging Assembly EUV telescopes, combined with several data-driven models. Similar to previous studies (Kozarev et al., 2011; Downs et al., 2012), we determined that the observed feature is a driven magnetohydrodynamic (MHD) wave, which steepens into a shock within the AIA field of view (FOV). In that study, we obtained high-temporal resolution estimates of parameters of the OCBF, which regulate the efficiency of acceleration of charged particles within the theoretical framework of Diffusive Shock Acceleration (DSA). These parameters include the time-dependent shock radius Rsh, speed V sh and strength r, as well as the upstream (in the shock frame) potential coronal magnetic field orientations with respect of the shock surface normal, θBN. Because of the very high cadence of the AIA telescope, we were able to obtain estimates of these quantities for every 12 seconds of the approximately 8 minutes, which the OCBF spent in the AIA field of view. Here we present a simple analytical model for the particle acceleration from low in the corona, which has been developed to incorporate the remotely observed OCBF properties described above. We showcase the model by applying it to the event studied in Kozarev et al. (2015), and show that it can produce significant increase in the particle energies during the short passage of the OCBF in the AIA field of view.

  6. Effect of resistivity gradient on laser-driven electron transport and ion acceleration

    SciTech Connect

    Zhuo, H. B.; Yang, X. H.; Ma, Y. Y.; Li, X. H.; Zhou, C. T.; Yu, M. Y.

    2013-09-15

    The effect of resistivity gradient on laser-driven electron transport and ion acceleration is investigated using collisional particle-in-cell simulation. The study is motivated by recent proton acceleration experiments [Gizzi et al., Phys. Rev. ST Accel. Beams 14, 011301 (2011)], which showed significant effect of the resistivity gradient in layered targets on the proton angular spread. This effect is reproduced in the present simulations. It is found that resistivity-gradient generation of magnetic fields and inhibition of electron transport is significantly enhanced when the feedback interaction between the magnetic field and the fast-electron current is included. Filamentation of the laser-generated hot electron jets inside the target, considered as the origin of the nonuniform proton patterns observed in the experiments, is clearly suppressed by the resistive magnetic field. As a result, the electrostatic sheath field at the target back surface acquires a relatively smooth profile, which contributes to the superior quality of the proton beams accelerated off layered targets in the experiments.

  7. Dosimetric characterization of the irradiation cavity for accelerator-based in vivo neutron activation analysis.

    PubMed

    Byun, S H; Pejović-Milić, A; McMaster, S; Matysiak, W; Aslam; Liu, Z; Watters, L M; Prestwich, W V; McNeill, F E; Chettle, D R

    2007-03-21

    A neutron irradiation cavity for in vivo activation analysis has been characterized to estimate its dosimetric specifications. The cavity is defined to confine irradiation to the hand and modifies the neutron spectrum produced by a low energy accelerator neutron source to optimize activation per dose. Neutron and gamma-ray dose rates were measured with the microdosimetric technique using a tissue-equivalent proportional counter at the hand irradiation site and inside the hand access hole. For the outside of the cavity, a spherical neutron dose equivalent meter and a Farmer dosemeter were employed instead due to the low intensity of the radiation field. The maximum dose equivalent rate at the outside of the cavity was 2.94 microSv/100 microA min, which is lower by a factor of 1/2260 than the dose rate at the hand irradiation position. The local dose contributions from a hand, an arm and the rest of a body to the effective dose rate were estimated to be 1.73, 0.782 and 2.94 microSv/100 microA min, respectively. For the standard irradiation protocol of the in vivo hand activation, 300 microA min, an effective dose of 16.3 microSv would be delivered. PMID:17455391

  8. SU-E-T-543: Measurement of Neutron Activation From Different High Energy Varian Linear Accelerators

    SciTech Connect

    Thatcher, T; Madsen, S; Sudowe, R; Meigooni, A Soleimani

    2015-06-15

    Purpose: Linear accelerators producing photons above 10 MeV may induce photonuclear reactions in high Z components of the accelerator. These liberated neutrons can then activate the structural components of the accelerator and other materials in the beam path through neutron capture reactions. The induced activity within the accelerator may contribute to additional dose to both patients and personnel. This project seeks to determine the total activity and activity per activated isotope following irradiation in different Varian accelerators at energies above 10 MeV. Methods: A Varian 21IX accelerator was used to irradiate a 30 cm × 30 cm × 20 cm solid water phantom with 15 MV x-rays. The phantom was placed at an SSD of 100 cm and at the center of a 20 cm × 20 cm field. Activation induced gamma spectra were acquired over a 5 minute interval after 1 and 15 minutes from completion of the irradiation. All measurements were made using a CANBERRA Falcon 5000 Portable HPGe detector. The majority of measurements were made in scattering geometry with the detector situated at 90° to the incident beam, 30 cm from the side of the phantom and approximately 10 cm from the top. A 5 minute background count was acquired and automatically subtracted from all subsequent measurements. Photon spectra were acquired for both open and MLC fields. Results: Based on spectral signatures, nuclides have been identified and their activities calculated for both open and MLC fields. Preliminary analyses suggest that activities from the activation products in the microcurie range. Conclusion: Activation isotopes have been identified and their relative activities determined. These activities are only gross estimates since efficiencies have not been determined for this source-detector geometry. Current efforts are focused on accurate determination of detector efficiencies using Monte Carlo calculations.

  9. Selection of flowing liquid lead target structural materials for accelerator driven transmutation applications

    SciTech Connect

    Park, J.J.; Buksa, J.J.

    1994-08-01

    The beam entry window and container for a liquid lead spallation target will be exposed to high fluxes of protons and neutrons that are both higher in magnitude and energy than have been experienced in proton accelerators and fission reactors, as well as in a corrosive environment. The structural material of the target should have a good compatibility with liquid lead, a sufficient mechanical strength at elevated temperatures, a good performance under an intense irradiation environment, and a low neutron absorption cross section; these factors have been used to rank the applicability of a wide range of materials for structural containment Nb-1Zr has been selected for use as the structural container for the LANL ABC/ATW molten lead target. Corrosion and mass transfer behavior for various candidate structural materials in liquid lead are reviewed, together with the beneficial effects of inhibitors and various coatings to protect substrate against liquid lead corrosion. Mechanical properties of some candidate materials at elevated temperatures and the property changes resulting from 800 MeV proton irradiation are also reviewed.

  10. Test of pixel detectors for laser-driven accelerated particle beams

    NASA Astrophysics Data System (ADS)

    Reinhardt, S.; Granja, C.; Krejci, F.; Assmann, W.

    2011-12-01

    Laser-driven accelerated (LDA) particle beams have due to the unique acceleration process very special properties. In particular they are created in ultra-short bunches of high intensity exceeding more than 107 \\frac{particles}{cm^{2} \\cdot ns} per bunch. Characterization of these beams is very limited with conventional particle detectors. Non-electronic detectors such as imaging plates or nuclear track detectors are, therefore, conventionally used at present. Moreover, all these detectors give only offline information about the particle pulse position and intensity as they require minutes to hours to be processed, calling for a new highly sensitive online device. Here, we present tests of different pixel detectors for real time detection of LDA ion pulses. Experiments have been performed at the Munich 14MV Tandem accelerator with 8-20 MeV protons in dc and pulsed beam, the latter producing comparable flux as a LDA ion pulse. For detection tests we chose the position-sensitive quantum-counting semiconductor pixel detector Timepix which also provides per-pixel energy- or time-sensitivity. Additionally other types of commercially available pixel detectors are being evaluated such as the RadEye™1, a large area (25 x 50 mm2) CMOS image sensor. All of these devices are able to resolve individual ions with high spatial- and energy-resolution down to the level of μm and tens of keV, respectively. Various beam delivering parameters of the accelerator were thus evaluated and verified. The different readout modes of the Timepix detector which is operated with an integrated USB-based readout interface allow online visualization of single and time-integrated events. Therefore Timepix offers the greatest potential in analyzing the beam parameters.

  11. Accelerated CMR using zonal, parallel and prior knowledge driven imaging methods

    PubMed Central

    Kozerke, Sebastian; Plein, Sven

    2008-01-01

    Accelerated imaging is highly relevant for many CMR applications as competing constraints with respect to spatiotemporal resolution and tolerable scan times are frequently posed. Three approaches, all involving data undersampling to increase scan efficiencies, are discussed in this review. Zonal imaging can be considered a niche but nevertheless has found application in coronary imaging and CMR flow measurements. Current work on parallel-transmit systems is expected to revive the interest in zonal imaging techniques. The second and main approach to speeding up CMR sequences has been parallel imaging. A wide range of CMR applications has benefited from parallel imaging with reduction factors of two to three routinely applied for functional assessment, perfusion, viability and coronary imaging. Large coil arrays, as are becoming increasingly available, are expected to support reduction factors greater than three to four in particular in combination with 3D imaging protocols. Despite these prospects, theoretical work has indicated fundamental limits of coil encoding at clinically available magnetic field strengths. In that respect, alternative approaches exploiting prior knowledge about the object being imaged as such or jointly with parallel imaging have attracted considerable attention. Five to eight-fold scan accelerations in cine and dynamic CMR applications have been reported and image quality has been found to be favorable relative to using parallel imaging alone. With all acceleration techniques, careful consideration of the limits and the trade-off between acceleration and occurrence of artifacts that may arise if these limits are breached is required. In parallel imaging the spatially varying noise has to be considered when measuring contrast- and signal-to-noise ratios. Also, temporal fidelity in images reconstructed with prior knowledge driven methods has to be studied carefully. PMID:18534005

  12. Laser energized traveling wave accelerator - a novel scheme for simultaneous focusing, energy selection and post-acceleration of laser-driven ions

    NASA Astrophysics Data System (ADS)

    Kar, Satyabrata

    2015-11-01

    All-optical approaches to particle acceleration are currently attracting a significant research effort internationally. Where intense laser driven proton beams, mainly by the so called Target Normal Sheath Acceleration mechanism, have attractive properties such as brightness, laminarity and burst duration, overcoming some of the inherent shortcomings, such as large divergence, broad spectrum and slow ion energy scaling poses significant scientific and technological challenges. High power lasers are capable of generating kiloampere current pulses with unprecedented short duration (10s of picoseconds). The large electric field from such localized charge pulses can be harnessed in a traveling wave particle accelerator arrangement. By directing the ultra-short charge pulse along a helical path surrounding a laser-accelerated ion beams, one can achieve simultaneous beam shaping and re-acceleration of a selected portion of the beam by the components of the associated electric field within the helix. In a proof-of-principle experiment on a 200 TW university-scale laser, we demonstrated post-acceleration of ~108 protons by ~5 MeV over less than a cm of propagation - i.e. an accelerating gradient ~0.5 GeV/m, already beyond what can be sustained by conventional accelerator technologies, with dynamic beam collimation and energy selection. These results open up new opportunities for the development of extremely compact and cost-effective ion accelerators for both established and innovative applications.

  13. An Electron Bunch Compression Scheme for a Superconducting Radio Frequency Linear Accelerator Driven Light Source

    SciTech Connect

    C. Tennant, S.V. Benson, D. Douglas, P. Evtushenko, R.A. Legg

    2011-09-01

    We describe an electron bunch compression scheme suitable for use in a light source driven by a superconducting radio frequency (SRF) linac. The key feature is the use of a recirculating linac to perform the initial bunch compression. Phasing of the second pass beam through the linac is chosen to de-chirp the electron bunch prior to acceleration to the final energy in an SRF linac ('afterburner'). The final bunch compression is then done at maximum energy. This scheme has the potential to circumvent some of the most technically challenging aspects of current longitudinal matches; namely transporting a fully compressed, high peak current electron bunch through an extended SRF environment, the need for a RF harmonic linearizer and the need for a laser heater. Additional benefits include a substantial savings in capital and operational costs by efficiently using the available SRF gradient.

  14. Attosecond Thomson-scattering x-ray source driven by laser-based electron acceleration

    SciTech Connect

    Luo, W.; Zhuo, H. B.; Yu, T. P.; Ma, Y. Y.; Song, Y. M.; Zhu, Z. C.; Yu, M. Y.

    2013-10-21

    The possibility of producing attosecond x-rays through Thomson scattering of laser light off laser-driven relativistic electron beams is investigated. For a ≤200-as, tens-MeV electron bunch produced with laser ponderomotive-force acceleration in a plasma wire, exceeding 10{sup 6} photons/s in the form of ∼160 as pulses in the range of 3–300 keV are predicted, with a peak brightness of ≥5 × 10{sup 20} photons/(s mm{sup 2} mrad{sup 2} 0.1% bandwidth). Our study suggests that the physical scheme discussed in this work can be used for an ultrafast (attosecond) x-ray source, which is the most beneficial for time-resolved atomic physics, dubbed “attosecond physics.”.

  15. High-intensity laser-driven proton acceleration enhancement from hydrogen containing ultrathin targets

    SciTech Connect

    Dollar, F.; Reed, S. A.; Matsuoka, T.; Bulanov, S. S.; Chvykov, V.; Kalintchenko, G.; McGuffey, C.; Rousseau, P.; Thomas, A. G. R.; Willingale, L.; Yanovsky, V.; Krushelnick, K.; Maksimchuk, A.; Litzenberg, D. W.

    2013-09-30

    Laser driven proton acceleration experiments from micron and submicron thick targets using high intensity (2 × 10{sup 21} W/cm{sup 2}), high contrast (10{sup −15}) laser pulses show an enhancement of maximum energy when hydrogen containing targets were used instead of non-hydrogen containing. In our experiments, using thin (<1μm) plastic foil targets resulted in maximum proton energies that were consistently 20%–100% higher than when equivalent thickness inorganic targets, including Si{sub 3}N{sub 4} and Al, were used. Proton energies up to 20 MeV were measured with a flux of 10{sup 7} protons/MeV/sr.

  16. Free-electron laser multiplex driven by a superconducting linear accelerator.

    PubMed

    Plath, Tim; Amstutz, Philipp; Bödewadt, Jörn; Brenner, Günter; Ekanayake, Nagitha; Faatz, Bart; Hacker, Kirsten; Honkavaara, Katja; Lazzarino, Leslie Lamberto; Lechner, Christoph; Maltezopoulos, Theophilos; Scholz, Matthias; Schreiber, Siegfried; Vogt, Mathias; Zemella, Johann; Laarmann, Tim

    2016-09-01

    Free-electron lasers (FELs) generate femtosecond XUV and X-ray pulses at peak powers in the gigawatt range. The FEL user facility FLASH at DESY (Hamburg, Germany) is driven by a superconducting linear accelerator with up to 8000 pulses per second. Since 2014, two parallel undulator beamlines, FLASH1 and FLASH2, have been in operation. In addition to the main undulator, the FLASH1 beamline is equipped with an undulator section, sFLASH, dedicated to research and development of fully coherent extreme ultraviolet photon pulses using external seed lasers. In this contribution, the first simultaneous lasing of the three FELs at 13.4 nm, 20 nm and 38.8 nm is presented. PMID:27577757

  17. Laser ion acceleration and neutron source in short-pulse solid- nanoparticle interaction

    NASA Astrophysics Data System (ADS)

    Nishihara, K.; Watari, T.; Matsukado, K.; Sekine, T.; Takeuchi, Y.; Takagi, M.; Satoh, N.; Kawashima, T.; Kan, H.

    2016-03-01

    We propose both an efficient neutron source and an extremely high energy proton source using solid CD and CH nano-particles, respectively, irradiated by an intense laser light. With a use of 3-d PIC simulations, we obtain an optimum CD radius for a neutron source, 250 nm and required laser field of a=eE/mωc ≈ 2, which results in D-D reaction rate of <σv> = 2x10-16 cm3/s, corresponding to an effective deuteron temperature of 500 keV to 1MeV. Reduction of neutron yield by pre-expansion is discussed. In a range of a ≈100, laser radiation pressure surrounding the particles accelerates electrons in the forward direction. Protons following the electrons become directional high energy, for example, proton energy of 450 MeV is obtained within 130 fs in CH particle interaction with 700 nm in radius. More than 10% of total protons in CH-particles are accelerated forward. Proton energy continuously increases with time and with the increase of particle size and the direction is also collimated with time.

  18. Towards a novel laser-driven method of exotic nuclei extraction-acceleration for fundamental physics and technology

    NASA Astrophysics Data System (ADS)

    Nishiuchi, M.; Sakaki, H.; Esirkepov, T. Zh.; Nishio, K.; Pikuz, T. A.; Faenov, A. Ya.; Skobelev, I. Yu.; Orlandi, R.; Pirozhkov, A. S.; Sagisaka, A.; Ogura, K.; Kanasaki, M.; Kiriyama, H.; Fukuda, Y.; Koura, H.; Kando, M.; Yamauchi, T.; Watanabe, Y.; Bulanov, S. V.; Kondo, K.; Imai, K.; Nagamiya, S.

    2016-04-01

    A combination of a petawatt laser and nuclear physics techniques can crucially facilitate the measurement of exotic nuclei properties. With numerical simulations and laser-driven experiments we show prospects for the Laser-driven Exotic Nuclei extraction-acceleration method proposed in [M. Nishiuchi et al., Phys, Plasmas 22, 033107 (2015)]: a femtosecond petawatt laser, irradiating a target bombarded by an external ion beam, extracts from the target and accelerates to few GeV highly charged short-lived heavy exotic nuclei created in the target via nuclear reactions.

  19. Generation of fast neutrons through deuteron acceleration at the PALS laser facility

    NASA Astrophysics Data System (ADS)

    Krása, J.; Klír, D.; Velyhan, A.; Řezáč, K.; Cikhardt, J.; Ryć, L.; Krouský, E.; Pfeifer, M.; De Marco, M.; Skála, J.; Dudžák, R.; Ullschmied, J.

    2016-03-01

    Recent experiments at the laser facility PALS focused on the laser driven fusion of deuterons are reviewed. They benefit of high reaction cross-sections and of a high number of multi-MeV deuterons from thick CD2 targets irradiated by intensity of 3× 1016 W cm-2. In the reported experiments fast fusion neutrons with energy up to 16 MeV were produced through 7Li(d, n)8Be and 11B(d, n)12C reactions in a pitcher-catcher target configuration. When using a large area CD2 foil as a secondary catcher target the total maximum neutron yield from the 2H(d, n)3He reaction increased by a factor of about 5, from 4× 108 to 2× 109. This result reveals that most of the deuterons having enough kinetic energy to enter a fusion reaction are emitted from the primary target into vacuum.

  20. Quasi-monoenergetic ion beam acceleration by laser-driven shock and solitary waves in near-critical plasmas

    NASA Astrophysics Data System (ADS)

    Zhang, W. L.; Qiao, B.; Huang, T. W.; Shen, X. F.; You, W. Y.; Yan, X. Q.; Wu, S. Z.; Zhou, C. T.; He, X. T.

    2016-07-01

    Ion acceleration in near-critical plasmas driven by intense laser pulses is investigated theoretically and numerically. A theoretical model has been given for clarification of the ion acceleration dynamics in relation to different laser and target parameters. Two distinct regimes have been identified, where ions are accelerated by, respectively, the laser-induced shock wave in the weakly driven regime (comparatively low laser intensity) and the nonlinear solitary wave in the strongly driven regime (comparatively high laser intensity). Two-dimensional particle-in-cell simulations show that quasi-monoenergetic proton beams with a peak energy of 94.6 MeV and an energy spread 15.8% are obtained by intense laser pulses at intensity I0 = 3 × 1020 W/cm2 and pulse duration τ = 0.5 ps in the strongly driven regime, which is more advantageous than that got in the weakly driven regime. In addition, 233 MeV proton beams with narrow spread can be produced by extending τ to 1.0 ps in the strongly driven regime.

  1. Time dependent Monte Carlo calculations of the ORELA (Oak Ridge Electron Linear Accelerator) target neutron spectrum

    SciTech Connect

    Cramer, S.N.; Perey, F.G.

    1990-01-01

    The time dependent spectrum of neutrons in the water-moderated Oak Ridge Electron Linear Accelerator (ORELA) target has been calculated using a modified version of the MORSE multi-group Monte Carlo code with an analytic hydrogen scattering model. Distributions of effective neutron distance traversed in the target are estimated with a time and energy dependent algorithm from the leakage normal to the target face. These data are used in the resonance shaped analyses of time-of-flight cross section measurements to account for the experimental resolution function. The 20 MeV--10 eV energy range is adequately represented in the MORSE code by the 174 group VITAMIN-E cross section library with a P{sub 5} expansion. An approximate representation of the ORELA positron source facility, recently installed near the target, has been included in the calculations to determine any perturbations the positron source might create in the computed neutron distributions from the target. A series of coupled Monte Carlo calculations was performed from the target to the positron source and back to the target using a next-event estimation surface source for each step. The principal effect of the positron source was found to be an increase in the distance for the lower energy neutron spectra, producing no real change in the distributions where the ORELA source is utilized for experiments. Different configurations for the target were investigated in order to simulate the placement of a shadow bar in the neutron beam. These beam configurations included neutrons escaping from : (1) the central tantalum plates only, (2) the entire target with the tantalum plates blocked out, and (3) only a small area from the water. Comparisons of the current data with previous calculations having a less detailed model of the tantalum plates have been satisfactory. 10 refs.

  2. Neutron production from a mobile linear accelerator operating in electron mode for intraoperative radiation therapy

    NASA Astrophysics Data System (ADS)

    Loi, G.; Dominietto, M.; Cannillo, B.; Ciocca, M.; Krengli, M.; Mones, E.; Negri, E.; Brambilla, M.

    2006-02-01

    Intraoperative electron beam radiotherapy is increasingly performed using mobile linac delivering therapeutic radiation doses in unshielded operating rooms. While no special neutron-shielding problem should arise for operation at 10 MeV or less, it is not clear whether this holds true for operation at higher energies. This paper reports the measured neutron production from a Mobetron mobile electron linac, operated at 12 MeV, and compares the results with those from a conventional linac, also operated at 12 MeV in electron mode. Neutron leakage measurements were performed by means of passive bubble detectors in the scattering foil, patient and floor planes. Neutron dose equivalent rates per unit of electron dose delivered by the Mobetron at its normal treatment distance (50 cm SSD) were 0.33 µSv Gy-1 at the accelerator head, 0.18 µSv Gy-1 in the patient plane at 15 cm from the beam axis and 0.31 µSv Gy-1 at the floor plane, on the beam axis and under the beam stopper. For a weekly workload of 250 Gy, the weekly neutron dose equivalents at 12 MeV for the Mobetron at a distance of 300 cm from the scattering foil were 14.3 and 1.7 µSv/week for floor below and adjoining areas on the same floor, respectively. Neutron dose equivalent rates generated from Mobetron are at least one order of magnitude lower than ones produced by a conventional linac operated at the same energy in electron mode. Mobetron can be used at 12 MeV in an unshielded operating room for a weekly workload of up to 250 Gy if the bremsstrahlung x-rays are shielded to negligible levels.

  3. Impulse Generation Mechanisms in a Laser-Driven In-Tube Accelerator

    NASA Astrophysics Data System (ADS)

    Choi, Jeong-Yeol; Kang, Ki-Ha; Sasoh, Akihiro; Jeung, In-Seuck; Urabe, Naohide; Kleine, Harald

    To enhance laser-propulsion thrust performance, a unique Laser-driven In-Tube Accelerator (LITA) has been developed. This paper numerically analyzes the impulse generation mechanisms in LITA. For this purpose, a LITA performance experiment was conducted in atmospheric air with a projectile installed on a ballistic pendulum to calibrate the numerical approximations. We conducted experimental flow visualization by framing shadowgraph and computational fluid dynamics solving the axi-symmetric Euler equation applied to an ideal gas. The results show that a laser-driven blast wave is generated by a spherical hot gas core where the supplied laser energy is absorbed first. The effect of confinement by the tube or shroud wall is confirmed. The impulse production is established not only from the interaction between the incident blast wave and projectile, but also from the following repetitive pressure waves. Assuming that about 30% of the input laser energy is absorbed by the working air, both the impulse and peak pressure agrees quantitatively between the experiment and numerical simulation.

  4. Relativistic klystron driven compact high gradient accelerator as an injector to an X-ray synchrotron radiation ring

    DOEpatents

    Yu, David U. L.

    1990-01-01

    A compact high gradient accelerator driven by a relativistic klystron is utilized to inject high energy electrons into an X-ray synchrotron radiation ring. The high gradients provided by the relativistic klystron enables accelerator structure to be much shorter (typically 3 meters) than conventional injectors. This in turn enables manufacturers which utilize high energy, high intensity X-rays to produce various devices, such as computer chips, to do so on a cost effective basis.

  5. Sloshing dynamics modulated fluid angular momentum and moment fluctuations driven by orbital gravity gradient and jitter accelerations in microgravity

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Pan, H. L.

    1995-01-01

    The dynamical behavior of spacecraft propellant affected by the asymmetric combined gravity gradient and jitter accelerations, in particular the effect of surface tension on partially-filled rotating fluids applicable to a full-scale Gravity Probe-B Spacecraft dewar tank has been investigated. Three different cases of orbital accelerations: (1) gravity gradient-dominated, (2) equally weighted between gravity gradient and jitter, and (3) gravity jitter-dominated accelerations are studied. The results of slosh wave excitation along the liquid-vapor interface induced by gravity gradient-dominated accelerations provide a torsional moment with tidal motion of bubble oscillations in the rotating dewar. The results are clearly seen from the twisting shape of the bubble oscillations driven by gravity gradient-dominated acceleration. The results of slosh wave excitation along the liquid-vapor interface induced by gravity jitter-dominated acceleration indicate the results of bubble motion in a manner of down-and-up and leftward-and-rightward movement of oscillation when the bubble is rotating with respect to rotating dewar axis. Fluctuations of angular momentum, fluid moment and bubble mass center caused by slosh wave excitations driven by gravity gradient acceleration or gravity jitter acceleration are also investigated.

  6. A comparison of acceleration methods for solving the neutron transport k-eigenvalue problem

    SciTech Connect

    Willert, Jeffrey; Park, H.; Knoll, D.A.

    2014-10-01

    Over the past several years a number of papers have been written describing modern techniques for numerically computing the dominant eigenvalue of the neutron transport criticality problem. These methods fall into two distinct categories. The first category of methods rewrite the multi-group k-eigenvalue problem as a nonlinear system of equations and solve the resulting system using either a Jacobian-Free Newton–Krylov (JFNK) method or Nonlinear Krylov Acceleration (NKA), a variant of Anderson Acceleration. These methods are generally successful in significantly reducing the number of transport sweeps required to compute the dominant eigenvalue. The second category of methods utilize Moment-Based Acceleration (or High-Order/Low-Order (HOLO) Acceleration). These methods solve a sequence of modified diffusion eigenvalue problems whose solutions converge to the solution of the original transport eigenvalue problem. This second class of methods is, in our experience, always superior to the first, as most of the computational work is eliminated by the acceleration from the LO diffusion system. In this paper, we review each of these methods. Our computational results support our claim that the choice of which nonlinear solver to use, JFNK or NKA, should be secondary. The primary computational savings result from the implementation of a HOLO algorithm. We display computational results for a series of challenging multi-dimensional test problems.

  7. A comparison of acceleration methods for solving the neutron transport k-eigenvalue problem

    NASA Astrophysics Data System (ADS)

    Willert, Jeffrey; Park, H.; Knoll, D. A.

    2014-10-01

    Over the past several years a number of papers have been written describing modern techniques for numerically computing the dominant eigenvalue of the neutron transport criticality problem. These methods fall into two distinct categories. The first category of methods rewrite the multi-group k-eigenvalue problem as a nonlinear system of equations and solve the resulting system using either a Jacobian-Free Newton-Krylov (JFNK) method or Nonlinear Krylov Acceleration (NKA), a variant of Anderson Acceleration. These methods are generally successful in significantly reducing the number of transport sweeps required to compute the dominant eigenvalue. The second category of methods utilize Moment-Based Acceleration (or High-Order/Low-Order (HOLO) Acceleration). These methods solve a sequence of modified diffusion eigenvalue problems whose solutions converge to the solution of the original transport eigenvalue problem. This second class of methods is, in our experience, always superior to the first, as most of the computational work is eliminated by the acceleration from the LO diffusion system. In this paper, we review each of these methods. Our computational results support our claim that the choice of which nonlinear solver to use, JFNK or NKA, should be secondary. The primary computational savings result from the implementation of a HOLO algorithm. We display computational results for a series of challenging multi-dimensional test problems.

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

    SciTech Connect

    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/sup 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/sup 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.

  9. Intense combined source of neutrons and photons for interrogation based on compact deuteron RF accelerator

    SciTech Connect

    Kurennoy, S. S.; Garnett, R. W.; Rybarcyk, L. J.

    2015-06-18

    Interrogation of special nuclear materials can benefit from mobile sources providing significant fluxes of neutrons (108/s at 2.5 MeV, 1010/s at 14.1 MeV) and of photons (>1012/s at 1-3 MeV). We propose a source that satisfies these requirements simultaneously plus also provides, via the reaction 11B(d,n)12C(γ15.1), a significant flux of 15-MeV photons, which are highly penetrating and optimal for inducing photo-fission in actinides. The source is based on a compact (< 5 m) deuteron RF accelerator that delivers an average current of a few mA of deuterons at 3-4 MeV to a boron target. The accelerator consists of a short RFQ followed by efficient inter-digital H-mode structures with permanent-magnet-quadrupole beam focusing [Kurennoy et al. (2012)], which suit perfectly for deuteron acceleration at low energies. Our estimates, based on recent measurements, indicate that the required fluxes of both neutrons and photons can be achieved at ~1 mA of 4-MeV deuterons. The goal of the proposed study is to confirm feasibility of the approach and develop requirements for future full system implementation.

  10. Intense combined source of neutrons and photons for interrogation based on compact deuteron RF accelerator

    DOE PAGESBeta

    Kurennoy, S. S.; Garnett, R. W.; Rybarcyk, L. J.

    2015-06-18

    Interrogation of special nuclear materials can benefit from mobile sources providing significant fluxes of neutrons (108/s at 2.5 MeV, 1010/s at 14.1 MeV) and of photons (>1012/s at 1-3 MeV). We propose a source that satisfies these requirements simultaneously plus also provides, via the reaction 11B(d,n)12C(γ15.1), a significant flux of 15-MeV photons, which are highly penetrating and optimal for inducing photo-fission in actinides. The source is based on a compact (< 5 m) deuteron RF accelerator that delivers an average current of a few mA of deuterons at 3-4 MeV to a boron target. The accelerator consists of a shortmore » RFQ followed by efficient inter-digital H-mode structures with permanent-magnet-quadrupole beam focusing [Kurennoy et al. (2012)], which suit perfectly for deuteron acceleration at low energies. Our estimates, based on recent measurements, indicate that the required fluxes of both neutrons and photons can be achieved at ~1 mA of 4-MeV deuterons. The goal of the proposed study is to confirm feasibility of the approach and develop requirements for future full system implementation.« less

  11. A comparison between a TESQ accelerator and a reactor as a neutron sources for BNCT

    NASA Astrophysics Data System (ADS)

    Burlon, A. A.; Kreiner, A. J.

    2008-03-01

    In this work, the performance of an accelerator-based neutron source design has been compared with that of a modern fluoride-filtered reactor-based epithermal beam having near-optimal quality for treatment of deep seated tumors in relation to its applicability for BNCT. The accelerator is a Tandem-Electrostatic-Quadrupole (TESQ) accelerator which is a design under development at the National Atomic Energy Commission (CNEA) in Buenos Aires, Argentina based on the 7Li(p,n)7Be reaction, relatively close to its energy threshold. The reactor is the Massachusetts Institute of Technology reactor upgraded with a Fission Converter Beam (MIT-FCB) and improved with an 8 mm thick 6Li filter. The comparison has been done by means of data reported on the MIT-FCB + 6Li filter performance and MCNP simulations on our TESQ design considering the neutron fluxes provided by the two sources and the doses delivered in a human phantom by both devices. The results show a deeper advantage depth (AD) for the TESQ which turns out to be a promising alternative to a reactor-based BNCT treatment.

  12. Converged accelerated finite difference scheme for the multigroup neutron diffusion equation

    SciTech Connect

    Terranova, N.; Mostacci, D.; Ganapol, B. D.

    2013-07-01

    Computer codes involving neutron transport theory for nuclear engineering applications always require verification to assess improvement. Generally, analytical and semi-analytical benchmarks are desirable, since they are capable of high precision solutions to provide accurate standards of comparison. However, these benchmarks often involve relatively simple problems, usually assuming a certain degree of abstract modeling. In the present work, we show how semi-analytical equivalent benchmarks can be numerically generated using convergence acceleration. Specifically, we investigate the error behavior of a 1D spatial finite difference scheme for the multigroup (MG) steady-state neutron diffusion equation in plane geometry. Since solutions depending on subsequent discretization can be envisioned as terms of an infinite sequence converging to the true solution, extrapolation methods can accelerate an iterative process to obtain the limit before numerical instability sets in. The obtained results have been compared to the analytical solution to the 1D multigroup diffusion equation when available, using FORTRAN as the computational language. Finally, a slowing down problem has been solved using a cascading source update, showing how a finite difference scheme performs for ultra-fine groups (104 groups) in a reasonable computational time using convergence acceleration. (authors)

  13. Enhanced electron yield from laser-driven wakefield acceleration in high-Z gas jets

    SciTech Connect

    Mirzaie, Mohammad; Hafz, Nasr A. M. Li, Song; Liu, Feng; Zhang, Jie; He, Fei; Cheng, Ya

    2015-10-15

    An investigation of the electron beam yield (charge) form helium, nitrogen, and neon gas jet plasmas in a typical laser-plasma wakefield acceleration experiment is carried out. The charge measurement is made by imaging the electron beam intensity profile on a fluorescent screen into a charge coupled device which was cross-calibrated with an integrated current transformer. The dependence of electron beam charge on the laser and plasma conditions for the aforementioned gases are studied. We found that laser-driven wakefield acceleration in low Z-gas jet targets usually generates high-quality and well-collimated electron beams with modest yields at the level of 10-100 pC. On the other hand, filamentary electron beams which are observed from high-Z gases at higher densities reached much higher yields. Evidences for cluster formation were clearly observed in the nitrogen gas jet target, where we received the highest electron beam charge of ∼1.7 nC. Those intense electron beams will be beneficial for the applications on the generation of bright X-rays, gamma rays radiations, and energetic positrons via the bremsstrahlung or inverse-scattering processes.

  14. Enhanced electron yield from laser-driven wakefield acceleration in high-Z gas jets.

    PubMed

    Mirzaie, Mohammad; Hafz, Nasr A M; Li, Song; Liu, Feng; He, Fei; Cheng, Ya; Zhang, Jie

    2015-10-01

    An investigation of the electron beam yield (charge) form helium, nitrogen, and neon gas jet plasmas in a typical laser-plasma wakefield acceleration experiment is carried out. The charge measurement is made by imaging the electron beam intensity profile on a fluorescent screen into a charge coupled device which was cross-calibrated with an integrated current transformer. The dependence of electron beam charge on the laser and plasma conditions for the aforementioned gases are studied. We found that laser-driven wakefield acceleration in low Z-gas jet targets usually generates high-quality and well-collimated electron beams with modest yields at the level of 10-100 pC. On the other hand, filamentary electron beams which are observed from high-Z gases at higher densities reached much higher yields. Evidences for cluster formation were clearly observed in the nitrogen gas jet target, where we received the highest electron beam charge of ∼1.7 nC. Those intense electron beams will be beneficial for the applications on the generation of bright X-rays, gamma rays radiations, and energetic positrons via the bremsstrahlung or inverse-scattering processes. PMID:26520950

  15. Ion acceleration at CME-driven shocks near the Earth and the Sun

    SciTech Connect

    Desai, Mihir; Dayeh, Maher; Ebert, Robert; Smith, Charles; Mason, Glenn; Li, G.

    2012-11-20

    We compare the behavior of heavy ion spectra during an Energetic Storm Particle (ESP) event that exhibited clear evidence of wave excitation with that observed during an intense, large gradual Solar Energetic Particle (SEP) event in which the associated <0.2 MeV/nucleon ions are delayed >12 hr. We interpret that the ESP event is an example of the first-order Fermi acceleration process where enhancements in the magnetic field power spectral densities around local ion cyclotron frequency {nu}{sub pc} indicate the presence of Alfven waves excited by accelerated protons streaming away from the in-situ interplanetary shock. The softening or unfolding of the CNO energy spectrum below {approx}200 keV/nucleon and the systematic organization of the Fe and O spectral roll-overs with the E/q ratio during the ESP event are likely due to M/Q-dependent trapping and scattering of the heavy ions by the proton-excited waves. Based on striking similarities in the spectral behavior observed upstream of both, the ESP and the SEP event, we suggest that coupling between proton-generated Alfven waves and energetic ions is also operating at the distant CME shock during the large, gradual SEP event, thereby providing us with a new, powerful tool to remotely probe the roles of shock geometries and wave-particle interactions at near-Sun CME-driven shocks.

  16. Enhanced electron yield from laser-driven wakefield acceleration in high-Z gas jets

    NASA Astrophysics Data System (ADS)

    Mirzaie, Mohammad; Hafz, Nasr A. M.; Li, Song; Liu, Feng; He, Fei; Cheng, Ya; Zhang, Jie

    2015-10-01

    An investigation of the electron beam yield (charge) form helium, nitrogen, and neon gas jet plasmas in a typical laser-plasma wakefield acceleration experiment is carried out. The charge measurement is made by imaging the electron beam intensity profile on a fluorescent screen into a charge coupled device which was cross-calibrated with an integrated current transformer. The dependence of electron beam charge on the laser and plasma conditions for the aforementioned gases are studied. We found that laser-driven wakefield acceleration in low Z-gas jet targets usually generates high-quality and well-collimated electron beams with modest yields at the level of 10-100 pC. On the other hand, filamentary electron beams which are observed from high-Z gases at higher densities reached much higher yields. Evidences for cluster formation were clearly observed in the nitrogen gas jet target, where we received the highest electron beam charge of ˜1.7 nC. Those intense electron beams will be beneficial for the applications on the generation of bright X-rays, gamma rays radiations, and energetic positrons via the bremsstrahlung or inverse-scattering processes.

  17. Analytic approach to nonlinear hydrodynamic instabilities driven by time-dependent accelerations

    SciTech Connect

    Mikaelian, K O

    2009-09-28

    We extend our earlier model for Rayleigh-Taylor and Richtmyer-Meshkov instabilities to the more general class of hydrodynamic instabilities driven by a time-dependent acceleration g(t) . Explicit analytic solutions for linear as well as nonlinear amplitudes are obtained for several g(t)'s by solving a Schroedinger-like equation d{sup 2}{eta}/dt{sup 2} - g(t)kA{eta} = 0 where A is the Atwood number and k is the wavenumber of the perturbation amplitude {eta}(t). In our model a simple transformation k {yields} k{sub L} and A {yields} A{sub L} connects the linear to the nonlinear amplitudes: {eta}{sup nonlinear} (k,A) {approx} (1/k{sub L})ln{eta}{sup linear} (k{sub L}, A{sub L}). The model is found to be in very good agreement with direct numerical simulations. Bubble amplitudes for a variety of accelerations are seen to scale with s defined by s = {integral} {radical}g(t)dt, while spike amplitudes prefer scaling with displacement {Delta}x = {integral}[{integral}g(t)dt]dt.

  18. Mobile-accelerator neutron-radiography system. Final report, February 1978-December 1983

    SciTech Connect

    Dance, W.E.; Carollo, S.F.; Bumgardner, H.M.

    1984-10-01

    The use of neutron radiography for the inspection and maintenance of large structures such as aircraft has been delayed by the absence of a mobile system particularly suited to the requirements of field use. This report describes the production, extensive field testing, evaluation and disposition of the first mobile neutron radiography system to satisfy the majority of requirements for field use. The system is based upon the concept of a mobile on-off neutron radiography system based on a sealed-tube ion accelerator as neutron source demonstrated earlier by the Vought Corporation. Primary features of the system are its self-propelled mobility, versatile positioning capability scaled to Army helicopter dimensions, an on-off beam capability, exposure capability measured in minutes, and suitability for AMMRC laboratory and field use. Included in the report are a description of all components of the system, an evaluation of the operation of the system, an evaluation of its radiographic capabilities, a description of installation elements for the AMMRC site, and recommendations for next-generation systems.

  19. Wakefield-induced ionization injection in beam-driven plasma accelerators

    NASA Astrophysics Data System (ADS)

    Martinez de la Ossa, A.; Mehrling, T. J.; Schaper, L.; Streeter, M. J. V.; Osterhoff, J.

    2015-09-01

    We present a detailed analysis of the features and capabilities of Wakefield-Induced Ionization (WII) injection in the blowout regime of beam driven plasma accelerators. This mechanism exploits the electric wakefields to ionize electrons from a dopant gas and trap them in a well-defined region of the accelerating and focusing wake phase, leading to the formation of high-quality witness-bunches [Martinez de la Ossa et al., Phys. Rev. Lett. 111, 245003 (2013)]. The electron-beam drivers must feature high-peak currents ( Ib 0 ≳ 8.5 kA ) and a duration comparable to the plasma wavelength to excite plasma waves in the blowout regime and enable WII injection. In this regime, the disparity of the magnitude of the electric field in the driver region and the electric field in the rear of the ion cavity allows for the selective ionization and subsequent trapping from a narrow phase interval. The witness bunches generated in this manner feature a short duration and small values of the normalized transverse emittance ( k p σ z ˜ k p ɛ n ˜ 0.1 ). In addition, we show that the amount of injected charge can be adjusted by tuning the concentration of the dopant gas species, which allows for controlled beam loading and leads to a reduction of the total energy spread of the witness beams. Electron bunches, produced in this way, fulfil the requirements to drive blowout regime plasma wakes at a higher density and to trigger WII injection in a second stage. This suggests a promising new concept of self-similar staging of WII injection in steps with increasing plasma density, giving rise to the potential of producing electron beams with unprecedented energy and brilliance from plasma-wakefield accelerators.

  20. Neutron source, linear-accelerator fuel enricher and regenerator and associated methods

    DOEpatents

    Steinberg, Meyer; Powell, James R.; Takahashi, Hiroshi; Grand, Pierre; Kouts, Herbert

    1982-01-01

    A device for producing fissile material inside of fabricated nuclear elements so that they can be used to produce power in nuclear power reactors. Fuel elements, for example, of a LWR are placed in pressure tubes in a vessel surrounding a liquid lead-bismuth flowing columnar target. A linear-accelerator proton beam enters the side of the vessel and impinges on the dispersed liquid lead-bismuth columns and produces neutrons which radiate through the surrounding pressure tube assembly or blanket containing the nuclear fuel elements. These neutrons are absorbed by the natural fertile uranium-238 elements and are transformed to fissile plutonium-239. The fertile fuel is thus enriched in fissile material to a concentration whereby they can be used in power reactors. After use in the power reactors, dispensed depleted fuel elements can be reinserted into the pressure tubes surrounding the target and the nuclear fuel regenerated for further burning in the power reactor.

  1. Neutron spectrometry of JET discharges with ICRH-acceleration of helium beam ions

    SciTech Connect

    Gatu Johnson, M.; Sunden, E. Andersson; Cecconello, M.; Conroy, S.; Ericsson, G.; Eriksson, J.; Hellesen, C.; Sangaroon, S.; Weiszflog, M.; Gorini, G.; Nocente, M.; Tardocchi, M.; Kiptily, V.; Sharapov, S. E. [JET-EFDA, Culham Science Centre, OX14 3DB, Abingdon; Euratom Eester, D. van [JET-EFDA, Culham Science Centre, OX14 3DB, Abingdon; LPP-ERM Collaboration: JET EFDA Contributors

    2010-10-15

    Recent experiments at JET aimed at producing {sup 4}He ions in the MeV range through third harmonic ion cyclotron resonance heating (ICRH) acceleration of {sup 4}He beams in a {sup 4}He dominated plasma. MeV range D was also present through parasitic ICRH absorption on residual D. In this contribution, we analyze TOFOR neutron spectrometer data from these experiments. A consistent description of the data is obtained with d(d,n){sup 3}He and {sup 9}Be({alpha},n){sup 12}C neutron components calculated using Stix distributions for the fast D and {sup 4}He, taking finite Larmor radius effects into account and with a ICRH power partition of P{sub D}{sup RF}=0.01xP{sub 4He}{sup RF}, in agreement with TOMCAT simulations.

  2. GPU-accelerated 3D neutron diffusion code based on finite difference method

    SciTech Connect

    Xu, Q.; Yu, G.; Wang, K.

    2012-07-01

    Finite difference method, as a traditional numerical solution to neutron diffusion equation, although considered simpler and more precise than the coarse mesh nodal methods, has a bottle neck to be widely applied caused by the huge memory and unendurable computation time it requires. In recent years, the concept of General-Purpose computation on GPUs has provided us with a powerful computational engine for scientific research. In this study, a GPU-Accelerated multi-group 3D neutron diffusion code based on finite difference method was developed. First, a clean-sheet neutron diffusion code (3DFD-CPU) was written in C++ on the CPU architecture, and later ported to GPUs under NVIDIA's CUDA platform (3DFD-GPU). The IAEA 3D PWR benchmark problem was calculated in the numerical test, where three different codes, including the original CPU-based sequential code, the HYPRE (High Performance Pre-conditioners)-based diffusion code and CITATION, were used as counterpoints to test the efficiency and accuracy of the GPU-based program. The results demonstrate both high efficiency and adequate accuracy of the GPU implementation for neutron diffusion equation. A speedup factor of about 46 times was obtained, using NVIDIA's Geforce GTX470 GPU card against a 2.50 GHz Intel Quad Q9300 CPU processor. Compared with the HYPRE-based code performing in parallel on an 8-core tower server, the speedup of about 2 still could be observed. More encouragingly, without any mathematical acceleration technology, the GPU implementation ran about 5 times faster than CITATION which was speeded up by using the SOR method and Chebyshev extrapolation technique. (authors)

  3. Measurements of photo-neutrons from a medical linear accelerator using CR-39 plastic nuclear track detectors

    NASA Astrophysics Data System (ADS)

    Monson, Jonathan Michael

    Photo-neutrons are produced when x-ray energies exceed 7 MeV. Photo-neutron production varies depending on x-ray beam energy. CR-39 PNTDs were used in this study to measure the neutron absorbed dose and dose equivalent produced by a Varian Clinac 23EX for x-ray beams of 6 and 18 MVp and with a Varian Trilogy using an x-ray beam of 10 MVp. Neutron absorbed dose and dose equivalent were measured at 100 cm SSD at 0, 20, and 40 cm off-axis from the primary beam in air. Using a polyethylene phantom the neutron absorbed dose and dose equivalent were measured at 100 cm SSD from the top of the phantom at 0, 5, and 10 cm from the surface, in the beam central axis and off-axis distances of 20 and 40 cm at a depth of 10 cm. The neutron absorbed dose and dose equivalent from medical linear accelerators have been measured from the LET spectrum of recoiled tracks produced in the CR-39 PNTDs for high energy neutrons (1-20 MeV) and the neutron dose equivalent for low energy (< 1 MeV) neutrons were measured using TRNDs. In this study, the experimentally measured absorbed dose and dose equivalent from photo-neutrons produced in a common medical linear accelerator operating at energies 10 and 18 MVp range from 0.2 microGy n/Gyx and 2 microSv n/Gyx to 495 microGy n/Gyx and 5500 microSv n/Gyx respectively. The neutron absorbed dose for the 6 MVp x-ray beam was measured to be 0 microGyn/Gyx. Low energy neutrons accounted for less than 1% of the neutron dose equivalent. Those detectors exposed inside of the phantom measured a higher contribution from high LET (> 100 keV/microm) particles than those detectors exposed in air.

  4. Transient particle acceleration in strongly magnetized neutron stars. II - Effects due to a dipole field geometry

    NASA Technical Reports Server (NTRS)

    Fatuzzo, Marco; Melia, Fulvio

    1991-01-01

    Sheared Alfven waves generated by nonradial crustal disturbances above the polar cap of a strongly magnetized neutron star induce an electric field component parallel to B. An attempt is made to determine the manner in which the strong radial dependence of B affects the propagation of these sheared Alfven waves, and whether this MHD process is still an effective particle accelerator. It is found that although the general field equation is quite complicated, a simple wavelike solution can still be obtained under the conditions of interest for which the Alfven phase velocity decouples from the wave equation. The results may be applicable to gamma-ray burst sources.

  5. Test simulation of neutron damage to electronic components using accelerator facilities

    NASA Astrophysics Data System (ADS)

    King, D. B.; Fleming, R. M.; Bielejec, E. S.; McDonald, J. K.; Vizkelethy, G.

    2015-12-01

    The purpose of this work is to demonstrate equivalent bipolar transistor damage response to neutrons and silicon ions. We report on irradiation tests performed at the White Sands Missile Range Fast Burst Reactor, the Sandia National Laboratories (SNL) Annular Core Research Reactor, the SNL SPHINX accelerator, and the SNL Ion Beam Laboratory using commercial silicon npn bipolar junction transistors (BJTs) and III-V Npn heterojunction bipolar transistors (HBTs). Late time and early time gain metrics as well as defect spectra measurements are reported.

  6. Ultracold electron bunch generation via plasma photocathode emission and acceleration in a beam-driven plasma blowout.

    PubMed

    Hidding, B; Pretzler, G; Rosenzweig, J B; Königstein, T; Schiller, D; Bruhwiler, D L

    2012-01-20

    Beam-driven plasma wakefield acceleration using low-ionization-threshold gas such as Li is combined with laser-controlled electron injection via ionization of high-ionization-threshold gas such as He. The He electrons are released with low transverse momentum in the focus of the copropagating, nonrelativistic-intensity laser pulse directly inside the accelerating or focusing phase of the Li blowout. This concept paves the way for the generation of sub-μm-size, ultralow-emittance, highly tunable electron bunches, thus enabling a flexible new class of an advanced free electron laser capable high-field accelerator. PMID:22400749

  7. Radiation dose measurements and Monte Carlo calculations for neutron and photon reactions in a human head phantom for accelerator-based boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Kim, Don-Soo

    Dose measurements and radiation transport calculations were investigated for the interactions within the human brain of fast neutrons, slow neutrons, thermal neutrons, and photons associated with accelerator-based boron neutron capture therapy (ABNCT). To estimate the overall dose to the human brain, it is necessary to distinguish the doses from the different radiation sources. Using organic scintillators, human head phantom and detector assemblies were designed, constructed, and tested to determine the most appropriate dose estimation system to discriminate dose due to the different radiation sources that will ultimately be incorporated into a human head phantom to be used for dose measurements in ABNCT. Monoenergetic and continuous energy neutrons were generated via the 7Li(p,n)7Be reaction in a metallic lithium target near the reaction threshold using the 5.5 MV Van de Graaff accelerator at the University of Massachusetts Lowell. A human head phantom was built to measure and to distinguish the doses which result from proton recoils induced by fast neutrons, alpha particles and recoil lithium nuclei from the 10B(n,alpha)7Li reaction, and photons generated in the 7Li accelerator target as well as those generated inside the head phantom through various nuclear reactions at the same time during neutron irradiation procedures. The phantom consists of two main parts to estimate dose to tumor and dose to healthy tissue as well: a 3.22 cm3 boron loaded plastic scintillator which simulates a boron containing tumor inside the brain and a 2664 cm3 cylindrical liquid scintillator which represents the surrounding healthy tissue in the head. The Monte Carlo code MCNPX(TM) was used for the simulation of radiation transport due to neutrons and photons and extended to investigate the effects of neutrons and other radiation on the brain at various depths.

  8. Brighter H/sup -/ source for the intense pulsed neutron source accelerator system

    SciTech Connect

    Stipp, V.; DeWitt, A.; Madsen, J.

    1983-01-01

    Further increases in the beam intensity of the Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory required the replacement of the H/sup -/ source with a higher current source. A magnetron ion source of Fermi National Accelerator Laboratory (FNAL) design was adapted with a grooved cathode to provide a stable 40 to 50 mA of beam operating at 30 Hz for up to a 90 ..mu..s pulse duration. Problems of space charge blowup due to the lack of neutralization of the H/sup -/ beam were solved by injecting additional gs into the 20 keV transport system. The source has recently been installed in the machine and the available input to the accelerator has more than doubled.

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

    SciTech Connect

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

    1998-11-01

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

  10. Neutrino-driven explosions of ultra-stripped Type Ic supernovae generating binary neutron stars

    NASA Astrophysics Data System (ADS)

    Suwa, Yudai; Yoshida, Takashi; Shibata, Masaru; Umeda, Hideyuki; Takahashi, Koh

    2015-12-01

    We study explosion characteristics of ultra-stripped supernovae (SNe), which are candidates of SNe generating binary neutron stars (NSs). As a first step, we perform stellar evolutionary simulations of bare carbon-oxygen cores of mass from 1.45 to 2.0 M⊙ until the iron cores become unstable and start collapsing. We then perform axisymmetric hydrodynamics simulations with spectral neutrino transport using these stellar evolution outcomes as initial conditions. All models exhibit successful explosions driven by neutrino heating. The diagnostic explosion energy, ejecta mass, Ni mass, and NS mass are typically ˜1050 erg, ˜0.1 M⊙, ˜0.01 M⊙, and ≈1.3 M⊙, which are compatible with observations of rapidly evolving and luminous transient such as SN 2005ek. We also find that the ultra-stripped SN is a candidate for producing the secondary low-mass NS in the observed compact binary NSs like PSR J0737-3039.

  11. On the Viscosity-driven Secular Instability in Rotating Neutron Stars

    NASA Astrophysics Data System (ADS)

    Skinner, David; Lindblom, Lee

    1996-04-01

    Rapidly rotating stars may be subject to a secular instability driven by viscosity. The oscillation modes that are susceptible to this instability are studied here in models of rigidly rotating neutron stars based on the polytropic and on several more realistic equations of state. For the polytropic models we confirm the classical result: that sufficiently rapidly rotating stars with adiabatic index γ > 2.237 suffer from the viscous instability, while those with γ <2.237 do not. For the more realistic models we find no viscous instability in the 1.4 Msun models from any equation of state. In sufficiently massive and rapidly rotating models, however, we do find the viscous instability in stars constructed from some of the realistic equations of state.

  12. Characteristics of a RF-Driven Ion Source for a Neutron Generator Used For Associated Particle Imaging

    SciTech Connect

    Wu, Ying; Hurley, John P.; Ji, Qing; Kwan, Joe; Leung, Ka-Ngo

    2008-08-08

    We present recent work on a prototype compact neutron generator for associated particle imaging (API). API uses alpha particles that are produced simultaneously with neutrons in the deuterium-tritium (2D(3T,n)4 alpha) fusion reaction to determine the direction of the neutrons upon exiting the reaction. This method determines the spatial position of each neutron interaction and requires the neutrons to be generated from a small spot in order to achieve high spatial resolution. The ion source for API is designed to produce a focused ion beam with a beam spot diameter of 1-mm or less on the target. We use an axial type neutron generator with a predicted neutron yield of 108 n/s for a 50 muA D/T ion beam current accelerated to 80 kV. The generator utilizes a RF planar spiral antenna at 13.56 MHz to create a highly efficient inductively-coupled plasma at the ion source. Experimental results show that beams with an atomic ion fraction of over 80percent can be obtained while utilizing only 100 watts of RF power in the ion source. A single acceleration gap with a secondary electron suppression electrode is used in the tube. Experimental results, such as the current density, atomic ion fraction, electron temperature, and electron density, from ion source testing will be discussed.

  13. ACCELERATING FUSION REACTOR NEUTRONICS MODELING BY AUTOMATIC COUPLING OF HYBRID MONTE CARLO/DETERMINISTIC TRANSPORT ON CAD GEOMETRY

    SciTech Connect

    Biondo, Elliott D; Ibrahim, Ahmad M; Mosher, Scott W; Grove, Robert E

    2015-01-01

    Detailed radiation transport calculations are necessary for many aspects of the design of fusion energy systems (FES) such as ensuring occupational safety, assessing the activation of system components for waste disposal, and maintaining cryogenic temperatures within superconducting magnets. Hybrid Monte Carlo (MC)/deterministic techniques are necessary for this analysis because FES are large, heavily shielded, and contain streaming paths that can only be resolved with MC. The tremendous complexity of FES necessitates the use of CAD geometry for design and analysis. Previous ITER analysis has required the translation of CAD geometry to MCNP5 form in order to use the AutomateD VAriaNce reducTion Generator (ADVANTG) for hybrid MC/deterministic transport. In this work, ADVANTG was modified to support CAD geometry, allowing hybrid (MC)/deterministic transport to be done automatically and eliminating the need for this translation step. This was done by adding a new ray tracing routine to ADVANTG for CAD geometries using the Direct Accelerated Geometry Monte Carlo (DAGMC) software library. This new capability is demonstrated with a prompt dose rate calculation for an ITER computational benchmark problem using both the Consistent Adjoint Driven Importance Sampling (CADIS) method an the Forward Weighted (FW)-CADIS method. The variance reduction parameters produced by ADVANTG are shown to be the same using CAD geometry and standard MCNP5 geometry. Significant speedups were observed for both neutrons (as high as a factor of 7.1) and photons (as high as a factor of 59.6).

  14. Time-dependent, Compositionally Driven Convection in the Oceans of Accreting Neutron Stars

    NASA Astrophysics Data System (ADS)

    Medin, Zach; Cumming, Andrew

    2015-03-01

    We discuss the effect of convection driven by chemical separation at the ocean-crust boundary of accreting neutron stars. We extend the steady-state results of Medin & Cumming to transient accretors, by considering the time-dependent cases of heating during accretion outbursts and cooling during quiescence. During accretion outbursts, inward heat transport has only a small effect on the temperature profile in the outer layers until the ocean is strongly enriched in light elements, a process that takes hundreds of years to complete. During quiescence, however, inward heat transport rapidly cools the outer layers of the ocean while keeping the inner layers hot. We find that this leads to a sharp drop in surface emission at around a week followed by a gradual recovery as cooling becomes dominated by the crust. Such a dip should be observable in the light curves of these neutron star transients, if enough data is taken at a few days to a month after the end of accretion. If such a dip is definitively observed, it will provide strong constraints on the chemical composition of the ocean and outer crust.

  15. First Observations of Laser-Driven Acceleration of Relativistic Electrons in a Semi-Infinite Vacuum Space

    SciTech Connect

    Plettner, T.; Byer, R.L.; Smith, T.I.; Colby, E.; Cowan, B.; Sears, C.M.S.; Spencer, J.E.; Siemann, R.H.; /SLAC

    2006-02-17

    We have observed acceleration of relativistic electrons in vacuum driven by a linearly polarized visible laser beam incident on a thin gold-coated reflective boundary. The observed energy modulation effect follows all the characteristics expected for linear acceleration caused by a longitudinal electric field. As predicted by the Lawson-Woodward theorem the laser driven modulation only appears in the presence of the boundary. It shows a linear dependence with the strength of the electric field of the laser beam and also it is critically dependent on the laser polarization. Finally, it appears to follow the expected angular dependence of the inverse transition radiation process. experiment as the Laser Electron Accelerator Project (LEAP).

  16. Direct current H{sup -} source for boron neutron capture therapy tandem accelerator

    SciTech Connect

    Belchenko, Yu.; Sanin, A.; Gusev, I.; Khilchenko, A.; Kvashnin, A.; Rashchenko, V.; Savkin, V.; Zubarev, P.

    2008-02-15

    One year experience of dc H{sup -} source operation at 2 MeV tandem accelerator is described. The source delivers H{sup -} ion beams with controlled current in the range of 1-8 mA and energy up to 25 keV. Normalized 1 rms emittance for 8 mA beam is less than 0.2{pi} mm mrad. Negative ions are produced on the cesiated anode of the Penning discharge, driven by plasma injection from the hollow cathode inserts.

  17. MANTRA: Measuring Neutron Capture Cross Sections in Actinides with Accelerator Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Bauder, W.; Pardo, R. C.; Collon, P.; Palchan, T.; Scott, R.; Vondrasek, R.; Nusair, O.; Nair, C.; Paul, M.; Kondev, F.; Chen, J.; Youinou, G.; Salvatores, M.; Palmotti, G.; Berg, J.; Maddock, T.; Imel, G.

    2013-10-01

    With rising global energy needs, there is substantial interest in nuclear energy research. To explore possibilities for advanced fuel cycles, better neutron cross section data are needed for the minor actinides. The MANTRA (Measurement of Actinide Neutron TRAsmutation) project will improve these data by measuring integral (n, γ) cross sections. The cross sections will be extracted by measuring isotopic ratios in pure actinide samples, irradiated in the Advanced Test Reactor at Idaho National Lab, using Accelerator Mass Spectrometry(AMS) at the Argonne Tandem Linac Accelerator System (ATLAS). MANTRA presents a unique AMS challenge because of the goal to measure multiple isotopic ratios on a large number of samples. To meet these challenges, we have modified the AMS setup at ATLAS to include a laser ablation system for solid material injection into our ECR ion source. I will present work on the laser ablation system and modified source geometry, as well as preliminary measurements of unirradiated actinide samples at ATLAS. This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.

  18. The physics of sub-critical lattices in accelerator driven hybrid systems: The MUSE experiments in the MASURCA facility

    SciTech Connect

    Chauvin, J. P.; Lebrat, J. F.; Soule, R.; Martini, M.; Jacqmin, R.; Imel, G. R.; Salvatores, M.

    1999-06-10

    Since 1991, the CEA has studied the physics of hybrid systems, involving a sub-critical reactor coupled with an accelerator. These studies have provided information on the potential of hybrid systems to transmute actinides and, long lived fission products. The potential of such a system remains to be proven, specifically in terms of the physical understanding of the different phenomena involved and their modelling, as well as in terms of experimental validation of coupled systems, sub-critical environment/accelerator. This validation must be achieved through mock-up studies of the sub-critical environments coupled to a source of external neutrons. The MUSE-4 mock-up experiment is planed at the MASURCA facility and will use an accelerator coupled to a tritium target. The great step between the generator used in the past and the accelerator will allow to increase the knowledge in hybrid physic and to decrease the experimental biases and the measurement uncertainties.

  19. Accelerating Data Acquisition, Reduction, and Analysis at the Spallation Neutron Source

    SciTech Connect

    Campbell, Stuart I; Kohl, James Arthur; Granroth, Garrett E; Miller, Ross G; Doucet, Mathieu; Stansberry, Dale V; Proffen, Thomas E; Taylor, Russell J; Dillow, David

    2014-01-01

    ORNL operates the world's brightest neutron source, the Spallation Neutron Source (SNS). Funded by the US DOE Office of Basic Energy Science, this national user facility hosts hundreds of scientists from around the world, providing a platform to enable break-through research in materials science, sustainable energy, and basic science. While the SNS provides scientists with advanced experimental instruments, the deluge of data generated from these instruments represents both a big data challenge and a big data opportunity. For example, instruments at the SNS can now generate multiple millions of neutron events per second providing unprecedented experiment fidelity but leaving the user with a dataset that cannot be processed and analyzed in a timely fashion using legacy techniques. To address this big data challenge, ORNL has developed a near real-time streaming data reduction and analysis infrastructure. The Accelerating Data Acquisition, Reduction, and Analysis (ADARA) system provides a live streaming data infrastructure based on a high-performance publish subscribe system, in situ data reduction, visualization, and analysis tools, and integration with a high-performance computing and data storage infrastructure. ADARA allows users of the SNS instruments to analyze their experiment as it is run and make changes to the experiment in real-time and visualize the results of these changes. In this paper we describe ADARA, provide a high-level architectural overview of the system, and present a set of use-cases and real-world demonstrations of the technology.

  20. (International Panel on 14 MeV Intense Neutron Source Based on Accelerators for Fusion Materials Study)

    SciTech Connect

    Thoms, K.R.; Wiffen, F.W.

    1991-02-14

    Both travelers were members of a nine-person US delegation that participated in an international workshop on accelerator-based 14 MeV neutron sources for fusion materials research hosted by the University of Tokyo. Presentations made at the workshop reviewed the technology developed by the FMIT Project, advances in accelerator technology, and proposed concepts for neutron sources. One traveler then participated in the initial meeting of the IEA Working Group on High Energy, High Flux Neutron Sources in which efforts were begun to evaluate and compare proposed neutron sources; the Fourth FFTF/MOTA Experimenters' Workshop which covered planning and coordination of the US-Japan collaboration using the FFTF reactor to irradiate fusion reactor materials; and held discussions with several JAERI personnel on the US-Japan collaboration on fusion reactor materials.

  1. Experimental and Simulated Characterization of a Beam Shaping Assembly for Accelerator- Based Boron Neutron Capture Therapy (AB-BNCT)

    NASA Astrophysics Data System (ADS)

    Burlon, Alejandro A.; Girola, Santiago; Valda, Alejandro A.; Minsky, Daniel M.; Kreiner, Andrés J.

    2010-08-01

    In the frame of the construction of a Tandem Electrostatic Quadrupole Accelerator facility devoted to the Accelerator-Based Boron Neutron Capture Therapy, a Beam Shaping Assembly has been characterized by means of Monte-Carlo simulations and measurements. The neutrons were generated via the 7Li(p, n)7Be reaction by irradiating a thick LiF target with a 2.3 MeV proton beam delivered by the TANDAR accelerator at CNEA. The emerging neutron flux was measured by means of activation foils while the beam quality and directionality was evaluated by means of Monte Carlo simulations. The parameters show compliance with those suggested by IAEA. Finally, an improvement adding a beam collimator has been evaluated.

  2. Experimental and Simulated Characterization of a Beam Shaping Assembly for Accelerator- Based Boron Neutron Capture Therapy (AB-BNCT)

    SciTech Connect

    Burlon, Alejandro A.; Valda, Alejandro A.; Girola, Santiago; Minsky, Daniel M.; Kreiner, Andres J.

    2010-08-04

    In the frame of the construction of a Tandem Electrostatic Quadrupole Accelerator facility devoted to the Accelerator-Based Boron Neutron Capture Therapy, a Beam Shaping Assembly has been characterized by means of Monte-Carlo simulations and measurements. The neutrons were generated via the {sup 7}Li(p, n){sup 7}Be reaction by irradiating a thick LiF target with a 2.3 MeV proton beam delivered by the TANDAR accelerator at CNEA. The emerging neutron flux was measured by means of activation foils while the beam quality and directionality was evaluated by means of Monte Carlo simulations. The parameters show compliance with those suggested by IAEA. Finally, an improvement adding a beam collimator has been evaluated.

  3. Preliminary energy-filtering neutron imaging with time-of-flight method on PKUNIFTY: A compact accelerator based neutron imaging facility at Peking University

    NASA Astrophysics Data System (ADS)

    Wang, Hu; Zou, Yubin; Wen, Weiwei; Lu, Yuanrong; Guo, Zhiyu

    2016-07-01

    Peking University Neutron Imaging Facility (PKUNIFTY) works on an accelerator-based neutron source with a repetition period of 10 ms and pulse duration of 0.4 ms, which has a rather low Cd ratio. To improve the effective Cd ratio and thus improve the detection capability of the facility, energy-filtering neutron imaging was realized with the intensified CCD camera and time-of-flight (TOF) method. Time structure of the pulsed neutron source was firstly simulated with Geant4, and the simulation result was evaluated with experiment. Both simulation and experiment results indicated that fast neutrons and epithermal neutrons were concentrated in the first 0.8 ms of each pulse period; meanwhile in the period of 0.8-2.0 ms only thermal neutrons existed. Based on this result, neutron images with and without energy filtering were acquired respectively, and it showed that detection capability of PKUNIFTY was improved with setting the exposure interval as 0.8-2.0 ms, especially for materials with strong moderating capability.

  4. Low-dose neutron dose response of zebrafish embryos obtained from the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility

    NASA Astrophysics Data System (ADS)

    Ng, C. Y. P.; Kong, E. Y.; Konishi, T.; Kobayashi, A.; Suya, N.; Cheng, S. H.; Yu, K. N.

    2015-09-01

    The dose response of embryos of the zebrafish, Danio rerio, irradiated at 5 h post fertilization (hpf) by 2-MeV neutrons with ≤100 mGy was determined. The neutron irradiations were made at the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility in the National Institute of Radiological Sciences (NIRS), Chiba, Japan. A total of 10 neutron doses ranging from 0.6 to 100 mGy were employed (with a gamma-ray contribution of 14% to the total dose), and the biological effects were studied through quantification of apoptosis at 25 hpf. The responses for neutron doses of 10, 20, 25, and 50 mGy approximately fitted on a straight line, while those for neutron doses of 0.6, 1 and 2.5 mGy exhibited neutron hormetic effects. As such, hormetic responses were generically developed by different kinds of ionizing radiations with different linear energy transfer (LET) values. The responses for neutron doses of 70 and 100 mGy were significantly below the lower 95% confidence band of the best-fit line, which strongly suggested the presence of gamma-ray hormesis.

  5. Optimisation of composite metallic fuel for minor actinide transmutation in an accelerator-driven system

    NASA Astrophysics Data System (ADS)

    Uyttenhove, W.; Sobolev, V.; Maschek, W.

    2011-09-01

    A potential option for neutralization of minor actinides (MA) accumulated in spent nuclear fuel of light water reactors (LWRs) is their transmutation in dedicated accelerator-driven systems (ADS). A promising fuel candidate dedicated to MA transmutation is a CERMET composite with Mo metal matrix and (Pu, Np, Am, Cm)O 2-x fuel particles. Results of optimisation studies of the CERMET fuel targeting to increasing the MA transmutation efficiency of the EFIT (European Facility for Industrial Transmutation) core are presented. In the adopted strategy of MA burning the plutonium (Pu) balance of the core is minimized, allowing a reduction in the reactivity swing and the peak power form-factor deviation and an extension of the cycle duration. The MA/Pu ratio is used as a variable for the fuel optimisation studies. The efficiency of MA transmutation is close to the foreseen theoretical value of 42 kg TW -1 h -1 when level of Pu in the actinide mixture is about 40 wt.%. The obtained results are compared with the reference case of the EFIT core loaded with the composite CERCER fuel, where fuel particles are incorporated in a ceramic magnesia matrix. The results of this study offer additional information for the EFIT fuel selection.

  6. Pre-design of MYRRHA, A Multipurpose Accelerator Driven System for Research and Development

    NASA Astrophysics Data System (ADS)

    D'hondt, P.; Abderrahim, H. Aït; Kupschus, P.; Malambu, E.; Aoust, Th.; Benoit, Ph.; Sobolev, V.; Van Tichelen, K.; Arien, B.; Vermeersch, F.; Jongen, Y.; Ternier, S.; Vandeplassche, D.

    2003-08-01

    One of the main SCK•CEN research facility, namely BR2, is nowadays arriving at an age of 40 years just like the major materials testing reactors (MTR) in the world and in Europe (i.e. BR2 (B-Mol), HFR (EU-Petten), OSIRIS (F-Saclay), R2 (S-Studsvik)). The MYRRHA facility in planning has been conceived as potentially replacing BR2 and to be a fast spectrum facility complementary to the thermal spectrum RJH (Réacteur Jules Horowitz) facility, in planning in France. This situation would give Europe a full research capability in terms of nuclear R&D. Furthermore, the disposal of radioactive wastes resulting from industrial nuclear energy production has still to find a fully satisfactory solution, especially in terms of environmental and social acceptability. Scientists are looking for ways to drastically reduce (by a factor of 100 or more) the radio-toxicity of the High Level Waste (HLW) to be stored in a deep geological repository. This can be achieved via burning of minor actinides (MA) and to a less extent of long-lived fission products (LLFP) in Accelerator Driven Systems. The MYRRHA project contribution will be in helping to demonstrate the ADS concept at reasonable power level and the demonstration of the technological feasibility of MA and LLFP transmutation under real conditions.

  7. Development of the CRISP Package for Spallation Studies and Accelerator-Driven Systems

    SciTech Connect

    Anefalos, S.; Deppman, A.; Silva, Gilson da; Maiorino, J.R.; Santos, A. dos; Garcia, F.

    2005-09-15

    Power generation from nuclear reactors provides an almost inexhaustive power source due to the huge quantities of nuclear fuel existent in our planet, which guarantees its utilization for thousands of years. Interest has been shifted to the so-called hybrid reactors [accelerator-driven systems (ADS)] as an alternative technology for power generation and transmutation, thus requiring precise knowledge about nuclear structure and nuclear reaction characteristics. Research groups from Instituto de Fisica, Universidade de Sao Paulo and Brazilian Center for Research in Physics made a joint effort to develop a computer program, CRISP, to calculate the intranuclear cascade proprieties and the nuclear evaporation process, present in all nuclear reactions with energies above a few tens of mega-electron-volts, using Monte Carlo techniques. Some reaction channels were included in these programs, resulting in a more realistic representation of the processes involved, aiming at reactor physics studies and academic studies about hadron and meson properties in nuclear matter. Some results obtained with this code and a comparison with experimental data are presented. Although all these results are preliminary, they are very consistent with the available experimental data. Since the applicability of the CRISP package has a wide range of options, especially in ADS, some results describing the effectiveness of the code were achieved.

  8. Pre-design of MYRRHA, A Multipurpose Accelerator Driven System for Research and Development

    SciTech Connect

    D'hondt, P.; Abderrahim, H. Aiet; Kupschus, P.; Malambu, E.; Aoust, Th.; Benoit, Ph.; Sobolev, V.; Tichelen, K. van; Arien, B.; Vermeersch, F.; Jongen, Y.; Ternier, S.; Vandeplassche, D.

    2003-08-26

    One of the main SCKCEN research facility, namely BR2, is nowadays arriving at an age of 40 years just like the major materials testing reactors (MTR) in the world and in Europe (i.e. BR2 (B-Mol), HFR (EU-Petten), OSIRIS (F-Saclay), R2 (S-Studsvik)). The MYRRHA facility in planning has been conceived as potentially replacing BR2 and to be a fast spectrum facility complementary to the thermal spectrum RJH (Reacteur Jules Horowitz) facility, in planning in France. This situation would give Europe a full research capability in terms of nuclear R and D. Furthermore, the disposal of radioactive wastes resulting from industrial nuclear energy production has still to find a fully satisfactory solution, especially in terms of environmental and social acceptability. Scientists are looking for ways to drastically reduce (by a factor of 100 or more) the radio-toxicity of the High Level Waste (HLW) to be stored in a deep geological repository. This can be achieved via burning of minor actinides (MA) and to a less extent of long-lived fission products (LLFP) in Accelerator Driven Systems. The MYRRHA project contribution will be in helping to demonstrate the ADS concept at reasonable power level and the demonstration of the technological feasibility of MA and LLFP transmutation under real conditions.

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

    SciTech Connect

    Saunders, A.; Makela, M.; Bagdasarova, Y.; Boissevain, J.; Bowles, T. J.; Currie, S. A.; Hill, R. E.; Hogan, G.; Morris, C. L.; Mortensen, R. N.; Ramsey, J.; Seestrom, S. J.; Sondheim, W. E.; Teasdale, W.; Wang, Z.; Back, H. O.; Broussard, L. J.; Hoagland, J.; Holley, A. T.; Pattie, R. W. Jr.; and others

    2013-01-15

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

  10. Feasibility study of an intense pulsed neutron source based on a powerful electron accelerator and a pulsed nuclear reactor

    SciTech Connect

    Bosamykin, V.S.; Voinov, M.A.; Gordeev, V.S.; Kuvshinov, M.I.; Morunov, K.A.; Pavlovskii, A.I.; Selemir, V.D.

    1995-12-31

    A promising candidate for a highly intense neutron source is a system coupling a powerful pulsed electron accelerator and a pulsed fast-neutron nuclear reactor. The LIU-10-GIR complex, located at the All-Russian Institute of Experimental Physics (VNIIEF), is described. Experiments were carried out during 1984--1990 to study the joint operation of these two widely differing physical systems and resolve basic scientific research problems. Experimental results are given, and the potential use of such a system as an intense neutron source is suggested.

  11. Study of proton acceleration at the target front surface in laser-solid interactions by neutron spectroscopy

    SciTech Connect

    Youssef, A.; Kodama, R.; Tampo, M.

    2006-03-15

    Proton acceleration inside solid LiF and CH-LiF targets irradiated by a 450-fs, 20-J, 1053-nm laser at an intensity of 3x10{sup 18} W/cm{sup 2} has been studied via neutron spectroscopy. Neutron spectra produced through the {sup 7}Li(p,n){sup 7}Be reaction that occurs between accelerated protons, at the front surface, and background {sup 7}Li ions inside the target. From measured and calculated spectra, by three-dimensional Monte Carlo code, the maximum energy, total number, and slope temperature of the accelerated protons are investigated. The study indicates that protons originate at the front surface and are accelerated to a maximum energy that is reasonably consistent with the calculated one due to the ponderomotive force.

  12. Neutron spectra around a tandem linear accelerator in the generation of (18)F with a bonner sphere spectrometer.

    PubMed

    Lagares, J I; Araque, J E Guerrero; Méndez-Villafañe, R; Arce, P; Sansaloni, F; Vela, O; Díaz, C; Campo, Xandra; Pérez, J M

    2016-08-01

    A Bonner sphere spectrometer was used to measure the neutron spectra produced at the collision of protons with an H2(18)O target at different angles. A unique H2(18)O target to produce (18)F was designed and placed in a Tandem linear particle accelerator which produces 8.5MeV protons. The neutron count rates measured with the Bonner spheres were unfolded with the MAXED code. With the GEANT4 Monte Carlo code the neutron spectrum induced in the (p, n) reaction was estimated, this spectrum was used as initial guess during unfolding. Although the cross section of the reaction (18)O(p,n)(18)F is well known, the neutron energy spectra is not correctly defined and it is necessary to verify the simulation with measurements. For this reason, the sensitivity of the unfolding method to the initial spectrum was analyzed applying small variation to the fast neutron peak. PMID:27235889

  13. Accelerator-driven subcritical fission in molten salt core: Closing the nuclear fuel cycle for green nuclear energy

    NASA Astrophysics Data System (ADS)

    McIntyre, Peter; Assadi, Saeed; Badgley, Karie; Baker, William; Comeaux, Justin; Gerity, James; Kellams, Joshua; McInturff, Al; Pogue, Nathaniel; Phongikaroon, Supathorn; Sattarov, Akhdiyor; Simpson, Michael; Sooby, Elizabeth; Tsvetkov, Pavel

    2013-04-01

    A technology for accelerator-driven subcritical fission in a molten salt core (ADSMS) is being developed as a basis for the destruction of the transuranics in used nuclear fuel. The molten salt fuel is a eutectic mixture of NaCl and the chlorides of the transuranics and fission products. The core is driven by proton beams from a strong-focusing cyclotron stack. This approach uniquely provides an intrinsically safe means to drive a core fueled only with transuranics, thereby eliminating competing breeding terms.

  14. Accelerator-driven subcritical fission in molten salt core: Closing the nuclear fuel cycle for green nuclear energy

    SciTech Connect

    McIntyre, Peter; Assadi, Saeed; Badgley, Karie; Baker, William; Comeaux, Justin; Gerity, James; Kellams, Joshua; McInturff, Al; Pogue, Nathaniel; Sattarov, Akhdiyor; Sooby, Elizabeth; Tsvetkov, Pavel; Phongikaroon, Supathorn; Simpson, Michael

    2013-04-19

    A technology for accelerator-driven subcritical fission in a molten salt core (ADSMS) is being developed as a basis for the destruction of the transuranics in used nuclear fuel. The molten salt fuel is a eutectic mixture of NaCl and the chlorides of the transuranics and fission products. The core is driven by proton beams from a strong-focusing cyclotron stack. This approach uniquely provides an intrinsically safe means to drive a core fueled only with transuranics, thereby eliminating competing breeding terms.

  15. A piezo-driven micro-inclination stage for calibration of a micro-acceleration transducer: structure and control strategy

    NASA Astrophysics Data System (ADS)

    Shao, Shubao; Song, Siyang; Xu, Minglong; Xie, Shilin; Li, Liang

    2016-02-01

    In some space applications, such as space navigation and vibration control of the large space structures, micro-acceleration transducers are required and have to be calibrated accurately. Unfortunately, providing extremely small static and quasi-static stimuli (accelerations) for the calibration of the micro-acceleration transducer has been a challenging task. This paper proposes a novel piezo-driven micro-inclination stage (PMIS) that can produce both discrete and continuous tumbles in a gravity field so that extremely small static and quasi-static stimuli (accelerations) can be obtained from a tiny component of the gravity constant. The proposed PMIS, which is driven by the lead zirconate titanate (PZT) stack, employs a rhombic mechanism to provide the PZT stack with a proper preload for the purpose of outputting a bidirectional force. To produce accurate static and quasi-static stimuli, the hysteresis non-linearity inherent in PZT stack is compensated by employing the strain feedback based adaptive control where the hysteresis property is identified online using the controlled auto-regressive moving average model. Furthermore, to improve the resolution of strain feedback, the strain sensitivity is maximized through structure optimization of the rhombic mechanism. The experimental results demonstrated that the proposed PMIS can produce minimal micro-inclination of {{0.1}\\prime \\prime} (corresponding to the induced micro-acceleration of 0.5μ g ) with the frequency ranging from 0 (DC) to 2 Hz.

  16. Proof-Of-Principle Experiment for Laser-Driven Acceleration of Relativistic Electrons in a Semi-Infinite Vacuum

    SciTech Connect

    Plettner, T.; Byer, R.L.; Colby, E.; Cowan, B.; Sears, C.M.S.; Spencer, J.E.; Siemann, R.H.; /SLAC

    2006-03-01

    We recently achieved the first experimental observation of laser-driven particle acceleration of relativistic electrons from a single Gaussian near-infrared laser beam in a semi-infinite vacuum. This article presents an in-depth account of key aspects of the experiment. An analysis of the transverse and longitudinal forces acting on the electron beam is included. A comparison of the observed data to the acceleration viewed as an inverse transition radiation process is presented. This is followed by a detailed description of the components of the experiment and a discussion of future measurements.

  17. Laser-driven proton and deuteron acceleration from a pure solid-density H2/D2 cryogenic jet

    NASA Astrophysics Data System (ADS)

    Kim, Jongjin; Gauthier, Maxence; Aurand, Bastian; Curry, Chandra; Goede, Sebastian; Goyon, Clement; Williams, Jackson; Kerr, Shaun; Ruby, John; Propp, Adrienne; Ramakrishna, Bhuvanesh; Pak, Art; Hazi, Andy; Glenzer, Siegfried; Roedel, Christian

    2015-11-01

    Laser-driven proton acceleration has become of tremendous interest for the fundamental science and the potential applications in tumor therapy and proton radiography. We have developed a cryogenic liquid hydrogen jet, which can deliver a self-replenishing target of pure solid-density hydrogen or deuterium. This allows for a target compatible with high-repetition-rate experiments and results in a pure hydrogen plasma, facilitating comparison with simulations. A new modification has allowed for the formation of jets with rectangular profiles, facilitating comparison with foil targets. This jet was installed at the Titan laser and driven by laser pulses of 40-60 J of 527 nm laser light in 1 ps. The resulting proton and deuteron spectra were measured in multiple directions with Thomson parabola spectrometers and RCF stacks. The spectral and angular information suggest contribution from both the TNSA and RPA acceleration mechanisms.

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

    SciTech Connect

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

    2014-01-01

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

  19. Accelerated carbonation of cement pastes in situ monitored by neutron diffraction

    SciTech Connect

    Castellote, M. Andrade, C.; Turrillas, X.; Campo, J.; Cuello, G.J.

    2008-12-15

    In-situ monitoring of the changes that take place in the phase composition of cement pastes during accelerated carbonation (100% CO{sub 2}) for different binders, has been carried out, by taking Neutron Diffraction patterns in parallel with the carbonation experiments. The variation of the intensity of chosen reflections for each phase along the experiment has been used to monitor concentration changes and has supplied data, in real time, for fractional conversion of different phases (Portlandite, Ettringite and CSH gel) of the hydrated cement pastes. Fitting of these results has allowed to make a qualitative approach to the kinetics of the carbonation of the different phases and extracting conclusions on the microstructural changes that takes place during the carbonation of cement pastes.

  20. A parametric model to describe neutron spectra around high-energy electron accelerators and its application in neutron spectrometry with Bonner Spheres

    NASA Astrophysics Data System (ADS)

    Bedogni, Roberto; Pelliccioni, Maurizio; Esposito, Adolfo

    2010-03-01

    Due to the increased interest of the scientific community in the applications of synchrotron light, there is an increasing demand of high-energy electron facilities, testified by the construction of several new facilities worldwide. The radiation protection around such facilities requires accurate experimental methods to determine the dose due to prompt radiation fields. Neutron fields, in particular, are the most complex to measure, because they extend in energy from thermal (10 -8 MeV) up to hundreds MeV and because the responses of dosemeters and survey meters usually have large energy dependence. The Bonner Spheres Spectrometer (BSS) is in practice the only instrument able to respond over the whole energy range of interest, and for this reason it is frequently used to derive neutron spectra and dosimetric quantities in accelerator workplaces. Nevertheless, complex unfolding algorithms are needed to derive the neutron spectra from the experimental BSS data. This paper presents a parametric model specially developed for the unfolding of the experimental data measured with BSS around high-energy electron accelerators. The work consists of the following stages: (1) Generation with the FLUKA code, of a set of neutron spectra representing the radiation environment around accelerators with different electron energies; (2) formulation of a parametric model able to describe these spectra, with particular attention to the high-energy component (>10 MeV), which may be responsible for a large part of the dose in workplaces; and (3) implementation of this model in an existing unfolding code.