Science.gov

Sample records for high power spallation

  1. Material issues relating to high power spallation neutron sources

    NASA Astrophysics Data System (ADS)

    Futakawa, M.

    2015-02-01

    Innovative researches using neutrons are being performed at the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), in which a mercury target system is installed for MW-class pulse spallation neutron sources. In order to produce neutrons by the spallation reaction, proton beams are injected into the mercury target. At the moment, when the intense proton beam hits the target, pressure waves are generated in mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel, leading to negative pressure that may cause cavitation along the vessel wall, i.e. on the interface between liquid and solid metals. On the other hand, the structural materials are subjected to irradiation damage due to protons and neutrons, very high cycle fatigue damages and so-called "liquid metal embrittlement". That is, the structural materials must be said to be exposed to the extremely severe environments. In the paper, research and development relating to the material issues in the high power spallation neutron sources that has been performed so far at J-PARC is summarized.

  2. High-Power Linac for the Spallation Neutron Source

    NASA Astrophysics Data System (ADS)

    Rej, D. J.

    2002-04-01

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

  3. Spallator: a new option for nuclear power

    SciTech Connect

    Steinberg, M.; Grand, P.; Takahashi, H.; Powell, J.R.; Kouts, H.J.

    1983-06-01

    The principles of the spallator reactor are reviewed. Advances in linear accelerator technology allow the design and construction of high current (hundreds of mA) continuous wave high energy (thousands of MeV) proton machines in the near term. Spallation neutronic calculations building on existing experimental results, indicate substantial neutron yields on uranium targets. Spallator target assembly designs based on water cooled reactor technology indicate operable efficient systems. Fuel cycles are presented which supply fissile material to thermal power reactors and reduce fission product waste. Preliminary comparative analysis indicates an economically competitive system in which a single purpose self-sufficient spallator supplies fuel to a number of LWRs. The spallator assures a long-term LWR power reactor economy. International interest in advancing the technology is indicated.

  4. Spallation Neutron Source reaches megawatt power

    SciTech Connect

    Dr. William F. Brinkman

    2009-09-30

    The Department of Energy's Spallation Neutron Source (SNS), already the world's most powerful facility for pulsed neutron scattering science, is now the first pulsed spallation neutron source to break the one-megawatt barrier. "Advances in the materials sciences are fundamental to the development of clean and sustainable energy technologies. In reaching this milestone of operating power, the Spallation Neutron Source is providing scientists with an unmatched resource for unlocking the secrets of materials at the molecular level," said Dr. William F. Brinkman, Director of DOE's Office of Science.

  5. Spallation Neutron Source reaches megawatt power

    ScienceCinema

    Dr. William F. Brinkman

    2016-07-12

    The Department of Energy's Spallation Neutron Source (SNS), already the world's most powerful facility for pulsed neutron scattering science, is now the first pulsed spallation neutron source to break the one-megawatt barrier. "Advances in the materials sciences are fundamental to the development of clean and sustainable energy technologies. In reaching this milestone of operating power, the Spallation Neutron Source is providing scientists with an unmatched resource for unlocking the secrets of materials at the molecular level," said Dr. William F. Brinkman, Director of DOE's Office of Science.

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

    SciTech Connect

    Not Available

    1994-01-01

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

  7. Spallation Neutron Source high-power Rf transmitter design for high availablility, ease of installation and cost containment

    SciTech Connect

    Bradley, J. T. , III; Rees, D. E.; Hardek, T. W.; Lynch, M. T.; Roybal, W. T.; Tallerico, P. J.

    2003-01-01

    The availability goals and installation schedule for the Spallation Neutron Source (SNS) have driven the availability and installation of the SNS linac's high-power RF systems. This paper discusses how the high-power RF systems' availability and installation goals have been addressed in the RF transmitter design and procurement. Design features that allow R1; component failures to be quickly diagnosed and repaired are also presented. Special attention has been given lo interlocks, PLC fault logging and real-time interfaces to thc accelerator's Experimental Physics and Industrial Control System (EPICS) archive system. The availability and cost motivations for the use of different RF transmitter designs in the normalconducting and super-conducting sections of the linac are reviewed. Factory iicceptance tests used to insure fully functional equipment and thereby reduce the time spent on installation and cotnmissioning of the RF transmitters are discussed. Transmitter installation experience and klystron conditioning experience is used to show how these design features have helped and will continue to help the SNS linac to meet its availability and schedule goals.

  8. In-situ structural integrity evaluation for high-power pulsed spallation neutron source - Effects of cavitation damage on structural vibration

    NASA Astrophysics Data System (ADS)

    Wan, Tao; Naoe, Takashi; Futakawa, Masatoshi

    2016-01-01

    A double-wall structure mercury target will be installed at the high-power pulsed spallation neutron source in the Japan Proton Accelerator Research Complex (J-PARC). Cavitation damage on the inner wall is an important factor governing the lifetime of the target-vessel. To monitor the structural integrity of the target vessel, displacement velocity at a point on the outer surface of the target vessel is measured using a laser Doppler vibrometer (LDV). The measured signals can be used for evaluating the damage inside the target vessel because of cyclic loading and cavitation bubble collapse caused by pulsed-beam induced pressure waves. The wavelet differential analysis (WDA) was applied to reveal the effects of the damage on vibrational cycling. To reduce the effects of noise superimposed on the vibration signals on the WDA results, analysis of variance (ANOVA) and analysis of covariance (ANCOVA), statistical methods were applied. Results from laboratory experiments, numerical simulation results with random noise added, and target vessel field data were analyzed by the WDA and the statistical methods. The analyses demonstrated that the established in-situ diagnostic technique can be used to effectively evaluate the structural response of the target vessel.

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

    SciTech Connect

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

    2001-06-01

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

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

    SciTech Connect

    Steinberg, M.

    1982-01-01

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

  11. Spallation neutron source and other high intensity froton sources

    SciTech Connect

    Weiren Chou

    2003-02-06

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

  12. 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.

  13. Triple Ion-Beam Studies of Radiation Damage in 9Cr2WVTa Ferritic/Martensitic Steel for a High Power Spallation Neutron Source

    SciTech Connect

    Lee, EH

    2001-08-01

    To simulate radiation damage under a future Spallation Neutron Source (SNS) environment, irradiation experiments were conducted on a candidate 9Cr-2WVTa ferritic/martensitic steel using the Triple Ion Facility (TIF) at ORNL. Irradiation was conducted in single, dual, and triple ion beam modes using 3.5 MeV Fe{sup 2}, 360 keV He{sup +}, and 180 keV H{sup +} at 80, 200, and 350 C. These irradiations produced various defects comprising black dots, dislocation loops, line dislocations, and gas bubbles, which led to hardening. The largest increase in hardness, over 63%, was observed after 50 dpa for triple beam irradiation conditions, revealing that both He and H are augmenting the hardening. Hardness increased less than 30% after 30 dpa at 200 C by triple beams, compatible with neutron irradiation data from previous work which showed about a 30% increase in yield strength after 27.2 dpa at 365 C. However, the very large concentrations of gas bubbles in the matrix and on lath and grain boundaries after these simulated SNS irradiations make predictions of fracture behavior from fission reactor irradiations to spallation target conditions inadvisable.

  14. Fundamental physics possibilities at the European Spallation Source

    NASA Astrophysics Data System (ADS)

    Klinkby, Esben; N-Nbar Collaboration; Soldner, Torsten; ANNI Collaboration

    2016-09-01

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

  15. Overview of Spallation Neutron Source Physics

    NASA Astrophysics Data System (ADS)

    Russell, G. J.; Pitcher, E. J.; Muhrer, G.; Mezei, F.; Ferguson, P. D.

    In December 1971 , the world's most advanced steady-state research reactor, the High Flux Reactor at the Institut Laue-Langevin (ILL) in Grenoble, France, reached full power operation. The reactor has recently undergone an extensive renovation, is equipped with hot and cold sources, and has a complement of word class instruments. As such, the ILL reactor is the worldwide center for neutron research at a reactor installation. With present technology, the constraints of heat removal and fuel cost place a limit on the available flux of a steadystate research reactor at levels not much higher than that of the ILL reactor. There has been extensive progress worldwide to realize new high-flux neutron facilities using the technology of spallation. When coupled with the spallation process in appropriate target materials, highpower accelerators can be used to produce large numbers of neutrons, thus providing an alternate method to the use of nuclear reactors for this purpose. Spallation technology has recently become increasingly focussed on pulsed spallation neutron sources. Pulsed spallation neutron sources avoid the limitations of high time-average heat removal by producing neutrons for only a small fraction of the time. Also, the amount of energy deposited per useful neutron produced from spallation is less than that from fission. During the pulse, the available neutron flux from a pulsed spallation source can be much more intense than that obtainable in a steady-state reactor. Furthermore, pulsed neutron sources have certain unique features, which open up qualitatively new areas of science, which are not accessible to steady-state reactors. We discuss here the spallation process and spallation neutron sources. We compare the qualitative differences between fission and spallation and provide absolute neutron intensities for cold neutron production from a liquid H2, moderator at the Manuel Lujan Jr. Neutron Scattering Center (Lujan Center) short-pulse pulsed spallation

  16. Production of Actinium-225 via High Energy Proton Induced Spallation of Thorium-232

    SciTech Connect

    Harvey, James T.; Nolen, Jerry; Vandergrift, George; Gomes, Itacil; Kroc, Tom; Horwitz, Phil; McAlister, Dan; Bowers, Del; Sullivan, Vivian; Greene, John

    2011-12-30

    The science of cancer research is currently expanding its use of alpha particle emitting radioisotopes. Coupled with the discovery and proliferation of molecular species that seek out and attach to tumors, new therapy and diagnostics are being developed to enhance the treatment of cancer and other diseases. This latest technology is commonly referred to as Alpha Immunotherapy (AIT). Actinium-225/Bismuth-213 is a parent/daughter alpha-emitting radioisotope pair that is highly sought after because of the potential for treating numerous diseases and its ability to be chemically compatible with many known and widely used carrier molecules (such as monoclonal antibodies and proteins/peptides). Unfortunately, the worldwide supply of actinium-225 is limited to about 1,000mCi annually and most of that is currently spoken for, thus limiting the ability of this radioisotope pair to enter into research and subsequently clinical trials. The route proposed herein utilizes high energy protons to produce actinium-225 via spallation of a thorium-232 target. As part of previous R and D efforts carried out at Argonne National Laboratory recently in support of the proposed US FRIB facility, it was shown that a very effective production mechanism for actinium-225 is spallation of thorium-232 by high energy proton beams. The base-line simulation for the production rate of actinium-225 by this reaction mechanism is 8E12 atoms per second at 200 MeV proton beam energy with 50 g/cm2 thorium target and 100 kW beam power. An irradiation of one actinium-225 half-life (10 days) produces {approx}100 Ci of actinium-225. For a given beam current the reaction cross section increases slightly with energy to about 400 MeV and then decreases slightly for beam energies in the several GeV regime. The object of this effort is to refine the simulations at proton beam energies of 400 MeV and above up to about 8 GeV. Once completed, the simulations will be experimentally verified using 400 MeV and 8 Ge

  17. High-pressure beamline (PLANET) at the spallation neutron source, J-PARC (Invited)

    NASA Astrophysics Data System (ADS)

    Kagi, H.; Hattori, T.; Arima, H.; Utsumi, W. S.; Komatsu, K.; Nagai, T.; Yagi, T.

    2009-12-01

    Material and Life Science experimental Facility (MLF) of Japan Proton Accelerator Research Complex (J-PARC) will be one of the most powerful spallation neutron facilities in the world. The pulsed neutron source with a liquid Hg target is designed to be running at 25 Hz with a power of 1 MW. We have started the construction of the powder diffractometer dedicated to high-pressure experiments (PLANET) on BL-11. PLANET aims to study structures of hydrogen-bearing materials including dense hydrous minerals of the Earth’s deep interior, magmas and light element liquids. The instrument will realize diffraction and radiography experiments for powder and liquid/glass samples at high pressures up to 20 GPa and 2000 K using a large sized multi-anvil hydraulic press that can apply forces of ˜1500 ton. The instrument views a decoupled liquid H2 moderator with a cross section of 100 × 100 mm2. The primary and secondary fight paths are 25 m and 1.5 m, respectively. The 11.5-m-long supermirror guide with elliptical shape starts at a distance of 11.5 m from the moderator. Design of elliptical geometry is optimized by means of incorporating several different grade mirrors and linear approximation with planar guide in order to save cost for production without degradation of the intensity performance. The guide has a rectangular cross-section and consists of four walls coated with supermirror material. Sample is placed at 2 m from the guide exit. The 90° detectors will be installed at 1.5 m from the sample position. For the powder diffraction measurements using a multi-anvil press, an incident neutron beam passes through the vertical anvil gaps and irradiates the sample in the pressure medium. Diffracted neutrons go through the other anvil gaps at 90° direction. Half inch 3He linear position sensitive detectors with 600 mm length will be arranged horizontally and form these detector banks, which cover the scattering angle of 79° ≤ 2θ ≤ 101° and -35° ≤ Φ ≤ +35°. The

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  19. Science opportunities at high power accelerators like APT

    SciTech Connect

    Browne, J.C.

    1996-12-31

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

  20. Pulsed spallation Neutron Sources

    SciTech Connect

    Carpenter, J.M.

    1994-12-31

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

  1. Pulsed spallation neutron sources

    SciTech Connect

    Carpenter, J.M.

    1996-05-01

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

  2. Further considerations of spallation effects

    NASA Technical Reports Server (NTRS)

    Dyer, C.

    1973-01-01

    Trapped photon and cosmic ray effects on spallation in the UK-5 (hard X ray telescope) central crystal were measured. Both low dose and high dose effects were considered. Decay results are presented in tables.

  3. BEAM LOSS MITIGATION IN THE OAK RIDGE SPALLATION NEUTRON SOURCE

    SciTech Connect

    Plum, Michael A

    2012-01-01

    The Oak Ridge Spallation Neutron Source (SNS) accelerator complex routinely delivers 1 MW of beam power to the spallation target. Due to this high beam power, understanding and minimizing the beam loss is an ongoing focus area of the accelerator physics program. In some areas of the accelerator facility the equipment parameters corresponding to the minimum loss are very different from the design parameters. In this presentation we will summarize the SNS beam loss measurements, the methods used to minimize the beam loss, and compare the design vs. the loss-minimized equipment parameters.

  4. Analytical calculations and Monte-Carlo simulations of a high-resolution backscattering spectrometer for the long wavelength target station at the Spallation neutron source

    NASA Astrophysics Data System (ADS)

    Bordallo, H. N.; Herwig, K. W.; Zsigmond, G.

    2002-09-01

    Using the Monte-Carlo simulation programs McStas and VITESS, we present the design principles of the proposed high-resolution inverse geometry spectrometer on the Spallation neutron source (SNS)—long wavelength target station (LWTS). LWTS will enable the combination of large energy and momentum transfer ranges with energy resolution. Indeed the resolution of this spectrometer lie between that routinely achieved by spin echo techniques and the design goal of the high-power target station (HPTS) backscattering spectrometer. This niche of energy resolution is interesting for the study of slow motions of large objects and we are led to the domain of large molecules—polymers and biological molecules.

  5. GRAIN-SCALE FAILURE IN THERMAL SPALLATION DRILLING

    SciTech Connect

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

    2012-01-19

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

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

    SciTech Connect

    Bryant, Rebecca; Kszos, Lynn A

    2011-03-01

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

  7. SPALLATION NEUTRON SOURCE OPERATIONAL EXPERIENCE AT 1 MW

    SciTech Connect

    Galambos, John D

    2011-01-01

    The Spallation Neutron Source (SNS) has been operating at the MW level for about one year. Experience in beam loss control and machine activation at this power level is presented. Also experience with machine protection systems is reviewed, which is critical at this power level. One of the most challenging operational aspects of high power operation has been attaining high availability, which is also discussed

  8. New generation high performance in situ polarized 3He system for time-of-flight beam at spallation sources

    NASA Astrophysics Data System (ADS)

    Jiang, C. Y.; Tong, X.; Brown, D. R.; Glavic, A.; Ambaye, H.; Goyette, R.; Hoffmann, M.; Parizzi, A. A.; Robertson, L.; Lauter, V.

    2017-02-01

    Modern spallation neutron sources generate high intensity neutron beams with a broad wavelength band applied to exploring new nano- and meso-scale materials from a few atomic monolayers thick to complicated prototype device-like systems with multiple buried interfaces. The availability of high performance neutron polarizers and analyzers in neutron scattering experiments is vital for understanding magnetism in systems with novel functionalities. We report the development of a new generation of the in situ polarized 3He neutron polarization analyzer for the Magnetism Reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory. With a new optical layout and laser system, the 3He polarization reached and maintained 84% as compared to 76% in the first-generation system. The polarization improvement allows achieving the transmission function varying from 50% to 15% for the polarized neutron beam with the wavelength band of 2-9 Angstroms. This achievement brings a new class of experiments with optimal performance in sensitivity to very small magnetic moments in nano systems and opens up the horizon for its applications.

  9. European Spallation Source

    NASA Astrophysics Data System (ADS)

    Eshraqi, Mohammad; McGinnis, David; Lindroos, Mats

    The following sections are included: * Neutron usage and historical background * Spallation * History of spallation sources * The ESS facility * The ESS linac * Beam physics * The front-end and the normal conducting linac * Superconducting linac * RF sources * Summary * References

  10. Neutron scattering instrumentation for biology at spallation neutron sources

    SciTech Connect

    Pynn, R.

    1994-12-31

    Conventional wisdom holds that since biological entities are large, they must be studied with cold neutrons, a domain in which reactor sources of neutrons are often supposed to be pre-eminent. In fact, the current generation of pulsed spallation neutron sources, such as LANSCE at Los Alamos and ISIS in the United Kingdom, has demonstrated a capability for small angle scattering (SANS) - a typical cold- neutron application - that was not anticipated five years ago. Although no one has yet built a Laue diffractometer at a pulsed spallation source, calculations show that such an instrument would provide an exceptional capability for protein crystallography at one of the existing high-power spoliation sources. Even more exciting is the prospect of installing such spectrometers either at a next-generation, short-pulse spallation source or at a long-pulse spallation source. A recent Los Alamos study has shown that a one-megawatt, short-pulse source, which is an order of magnitude more powerful than LANSCE, could be built with today`s technology. In Europe, a preconceptual design study for a five-megawatt source is under way. Although such short-pulse sources are likely to be the wave of the future, they may not be necessary for some applications - such as Laue diffraction - which can be performed very well at a long-pulse spoliation source. Recently, it has been argued by Mezei that a facility that combines a short-pulse spallation source similar to LANSCE, with a one-megawatt, long-pulse spallation source would provide a cost-effective solution to the global shortage of neutrons for research. The basis for this assertion as well as the performance of some existing neutron spectrometers at short-pulse sources will be examined in this presentation.

  11. Post irradiation examination of the Spallation Neutron Source target vessels

    SciTech Connect

    McClintock, David A; Ferguson, Phillip D; Mansur, Louis K

    2010-01-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is an accelerator-based pulsed neutron source that produces high-energy spallation neutrons by bombarding liquid mercury flowing through a stainless steel target vessel. During operation the proton beam and spallation neutrons produce radiation damage in the AISI 316L austenitic stainless steel target vessel and water-cooled shroud. The beam pulses also cause rapid heating of the liquid mercury, which may produce cavitation erosion damage on the inner surface of the target vessel. The cavitation erosion rate is thought to be highly sensitive to beam power and predicted to be the primary life-limiting factor of target vessel. Though mitigation of cavitation erosion and radiation damage to the target vessel will be a critical for successful high-power operation of the SNS facility, the effects of radiation damage and cavitation erosion to target vessels in liquid metal spallation systems are not well known. Therefore preparations are being undertaken to perform post irradiation examination (PIE) of the liquid mercury target vessel and water-cooled shroud after end-of-life occurs. An overview of the planned PIE for the SNS target vessel is presented here, including proposed techniques for specimen acquisition and subsequent material properties characterization.

  12. Testing Single Phase IGBT H-Bridge Switch Plates for the High Voltage Converter Modulator at the Spallation Neutron Source

    SciTech Connect

    Peplov, Vladimir V; Anderson, David E; Solley, Dennis J

    2014-01-01

    Three IGBT H-bridge switching networks are used in each High Voltage Converter Modulator (HVCM) system at the Spallation Neutron Source (SNS) to generate drive currents to three boost transformer primaries switching between positive and negative bus voltages at 20 kHz. Every switch plate assembly is tested before installing it into an operational HVCM. A Single Phase Test Stand has been built for this purpose, and it is used for adjustment, measurement and testing of different configurations of switch plates. This paper will present a description of the Test Stand configuration and discuss the results of testing switch plates with two different types of IGBT gate drivers currently in use on the HVCM systems. Comparison of timing characteristics of the original and new drivers and the resulting performance reinforces the necessity to replace the original H-bridge network drivers with the upgraded units.

  13. Spallation-induced fission reactions

    NASA Astrophysics Data System (ADS)

    Benlliure, J.; Rodríguez-Sánchez, J. L.

    2017-03-01

    During the last decade spallation-induced fission reactions have received particular attention because of their impact in the design of spallation-neutron sources or radioactive beam facilities, but also in the understanding of the fission process at high excitation energy. In this paper, we review the main progress brought by modern experimental techniques, in particular those based in the inverse kinematic, as well as the achievements in modelling these reactions. We will also address future possibilities for improving the investigation of fission dynamics.

  14. Dose measurements around spallation neutron sources.

    PubMed

    Fragopoulou, M; Stoulos, S; Manolopoulou, M; Krivopustov, M; Zamani, M

    2008-01-01

    Neutron dose measurements and calculations around spallation sources appear to be of great importance in shielding research. Two spallation sources were irradiated by high-energy proton beams delivered by the Nuclotron accelerator (JINR), Dubna. Neutrons produced by the spallation sources were measured by using solid-state nuclear track detectors. In addition, neutron dose was calculated after polyethylene and concrete, using a phenomenological model based on empirical relations applied in high-energy physics. The study provides an analytical and experimental neutron benchmark analysis using the transmission factor and a comparison between the experimental results and calculations.

  15. VERITAS: a high-flux neutron reflectometer with vertical sample geometry for a long pulse spallation source

    NASA Astrophysics Data System (ADS)

    Mattauch, S.; Ioffe, A.; Lott, D.; Menelle, A.; Ott, F.; Medic, Z.

    2016-04-01

    An instrument concept of a reflectometer with a vertical sample geometry fitted to the long pulse structure of a spallation source, called “VERITAS” at the ESS, is presented. It focuses on designing a reflectometer with high intensity at the lowest possible background following the users' demand to investigate thin layers or interfacial areas in the sub-nanometer length scale. The high intensity approach of the vertical reflectometer fits very well to the long pulse structure of the ESS. Its main goal is to deliver as much usable intensity as possible at the sample position and be able to access a reflectivity range of 8 orders of magnitude and more. The concept assures that the reflectivity measurements can be performed in its best way to maximize the flux delivered to the sample. The reflectometer is optimized for studies of (magnetic) layers having thicknesses down to 5Å and a surface area of 1x1cm2. With reflectivity measurements the depth-resolved, laterally averaged chemical and magnetic profile can be investigated. By using polarised neutrons, additional vector information on the in-plane magnetic correlations (off-specular scattering at the pm length scale, GISANS at the nm length scale) can be studied. The full polarisation analysis could be used for soft matter samples to correct for incoherent scattering which is presently limiting neutron reflectivity studies to a reflectivity range on the order of 10-6.

  16. Novel Large Area High Resolution Neutron Detector for the Spallation Neutron Source

    SciTech Connect

    Lacy, Jeffrey L

    2009-05-22

    Neutron scattering is a powerful technique that is critically important for materials science and structural biology applications. The knowledge gained from past developments has resulted in far-reaching advances in engineering, pharmaceutical and biotechnology industries, to name a few. New facilities for neutron generation at much higher flux, such as the SNS at Oak Ridge, TN, will greatly enhance the capabilities of neutron scattering, with benefits that extend to many fields and include, for example, development of improved drug therapies and materials that are stronger, longer-lasting, and more impact-resistant. In order to fully realize this enhanced potential, however, higher neutron rates must be met with improved detection capabilities, particularly higher count rate capability in large size detectors, while maintaining practicality. We have developed a neutron detector with the technical and economic advantages to accomplish this goal. This new detector has a large sensitive area, offers 3D spatial resolution, high sensitivity and high count rate capability, and it is economical and practical to produce. The proposed detector technology is based on B-10 thin film conversion of neutrons in long straw-like gas detectors. A stack of many such detectors, each 1 meter in length, and 4 mm in diameter, has a stopping power that exceeds that of He-3 gas, contained at practical pressures within an area detector. With simple electronic readout methods, straw detector arrays can provide spatial resolution of 4 mm FWHM or better, and since an array detector of such form consists of several thousand individual elements per square meter, count rates in a 1 m^2 detector can reach 2?10^7 cps. Moreover, each individual event can be timetagged with a time resolution of less than 0.1 ?sec, allowing accurate identification of neutron energy by time of flight. Considering basic elemental cost, this novel neutron imaging detector can be commercially produced economically

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

    SciTech Connect

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

    2016-01-15

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

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

    PubMed

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

    2016-01-01

    Neutron diffraction studies of metallic liquids provide valuable information about inherent topological and chemical ordering on multiple length scales as well as insight into dynamical processes at the level of a few atoms. However, there exist very few facilities in the world that allow such studies to be made of reactive metallic liquids in a containerless environment, and these are designed for use at reactor-based neutron sources. We present an electrostatic levitation facility, NESL (for Neutron ElectroStatic Levitator), which takes advantage of the enhanced capabilities and increased neutron flux available at spallation neutron sources (SNSs). NESL enables high quality elastic and inelastic neutron scattering experiments to be made of reactive metallic and other liquids in the equilibrium and supercooled temperature regime. The apparatus is comprised of a high vacuum chamber, external and internal neutron collimation optics, and a sample exchange mechanism that allows up to 30 samples to be processed between chamber openings. Two heating lasers allow excellent sample temperature homogeneity, even for samples approaching 500 mg, and an automated temperature control system allows isothermal measurements to be conducted for times approaching 2 h in the liquid state, with variations in the average sample temperature of less than 0.5%. To demonstrate the capabilities of the facility for elastic scattering studies of liquids, a high quality total structure factor for Zr64Ni36 measured slightly above the liquidus temperature is presented from experiments conducted on the nanoscale-ordered materials diffractometer (NOMAD) beam line at the SNS after only 30 min of acquisition time for a small sample (∼100 mg).

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

    DOE PAGES

    Mauro, N. A.; Vogt, A. J.; Derendorf, K. S.; ...

    2016-01-01

    Neutron diffraction studies of metallic liquids provide valuable information about inherent topological and chemical ordering on multiple length scales as well as insight into dynamical processes at the level of a few atoms. But, there exist very few facilities in the world that allow such studies to be made of reactive metallic liquids in a containerless environment, and these are designed for use at reactor-based neutron sources. We present an electrostatic levitation facility, NESL (for Neutron ElectroStatic Levitator), which takes advantage of the enhanced capabilities and increased neutron flux available at spallation neutron sources (SNSs). NESL enables high quality elasticmore » and inelastic neutron scattering experiments to be made of reactive metallic and other liquids in the equilibrium and supercooled temperature regime. The apparatus is comprised of a high vacuum chamber, external and internal neutron collimation optics, and a sample exchange mechanism that allows up to 30 samples to be processed between chamber openings. Two heating lasers allow excellent sample temperature homogeneity, even for samples approaching 500 mg, and an automated temperature control system allows isothermal measurements to be conducted for times approaching 2 h in the liquid state, with variations in the average sample temperature of less than 0.5%. Furthermore, to demonstrate the capabilities of the facility for elastic scattering studies of liquids, a high quality total structure factor for Zr64Ni36 measured slightly above the liquidus temperature is presented from experiments conducted on the nanoscale-ordered materials diffractometer (NOMAD) beam line at the SNS after only 30 min of acquisition time for a small sample ( 100 mg).« less

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

    SciTech Connect

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

    2016-01-01

    Neutron diffraction studies of metallic liquids provide valuable information about inherent topological and chemical ordering on multiple length scales as well as insight into dynamical processes at the level of a few atoms. But, there exist very few facilities in the world that allow such studies to be made of reactive metallic liquids in a containerless environment, and these are designed for use at reactor-based neutron sources. We present an electrostatic levitation facility, NESL (for Neutron ElectroStatic Levitator), which takes advantage of the enhanced capabilities and increased neutron flux available at spallation neutron sources (SNSs). NESL enables high quality elastic and inelastic neutron scattering experiments to be made of reactive metallic and other liquids in the equilibrium and supercooled temperature regime. The apparatus is comprised of a high vacuum chamber, external and internal neutron collimation optics, and a sample exchange mechanism that allows up to 30 samples to be processed between chamber openings. Two heating lasers allow excellent sample temperature homogeneity, even for samples approaching 500 mg, and an automated temperature control system allows isothermal measurements to be conducted for times approaching 2 h in the liquid state, with variations in the average sample temperature of less than 0.5%. Furthermore, to demonstrate the capabilities of the facility for elastic scattering studies of liquids, a high quality total structure factor for Zr64Ni36 measured slightly above the liquidus temperature is presented from experiments conducted on the nanoscale-ordered materials diffractometer (NOMAD) beam line at the SNS after only 30 min of acquisition time for a small sample ( 100 mg).

  1. HIGH POWER BEAM DUMP AND TARGET / ACCELERATOR INTERFACE PROCEDURES

    SciTech Connect

    Blokland, Willem; Plum, Michael A; Peters, Charles C; Brown, David L; Galambos, John D

    2013-01-01

    Satisfying operational procedures and limits for the beam target interface is a critical concern for high power operation at spallation neutron sources. At the Oak Ridge Spallation Neutron Source (SNS) a number of protective measures are instituted to ensure that the beam position, beam size and peak intensity are within acceptable limits at the target and high power Ring Injection Dump (RID). The high power beam dump typically handles up to 50 100 kW of beam power and its setup is complicated by the fact that there are two separate beam components simultaneously directed to the dump. The beam on target is typically in the 800-1000 kW average power level, delivered in sub- s 60 Hz pulses. Setup techniques using beam measurements to quantify the beam parameters at the target and dump will be described. However, not all the instrumentation used for the setup and initial qualification is available during high power operation. Additional techniques are used to monitor the beam during high power operation to ensure the setup conditions are maintained, and these are also described.

  2. Measurement of high-energy neutron flux above ground utilizing a spallation based multiplicity technique

    DOE PAGES

    Roecker, Caleb; Bernstein, Adam; Marleau, Peter; ...

    2016-11-14

    Cosmogenic high-energy neutrons are a ubiquitous, difficult to shield, poorly measured background. Above ground the high-energy neutron energy-dependent flux has been measured, with significantly varying results. Below ground, high-energy neutron fluxes are largely unmeasured. Here we present a reconstruction algorithm to unfold the incident neutron energy-dependent flux measured using the Multiplicity and Recoil Spectrometer (MARS), simulated test cases to verify the algorithm, and provide a new measurement of the above ground high-energy neutron energy-dependent flux with a detailed systematic uncertainty analysis. Uncertainty estimates are provided based upon the measurement statistics, the incident angular distribution, the surrounding environment of the Montemore » Carlo model, and the MARS triggering efficiency. Quantified systematic uncertainty is dominated by the assumed incident neutron angular distribution and surrounding environment of the Monte Carlo model. The energy-dependent neutron flux between 90 MeV and 400 MeV is reported. Between 90 MeV and 250 MeV the MARS results are comparable to previous Bonner sphere measurements. Over the total energy regime measured, the MARS result are located within the span of previous measurements. Lastly, these results demonstrate the feasibility of future below ground measurements with MARS.« less

  3. Measurement of high-energy neutron flux above ground utilizing a spallation based multiplicity technique

    SciTech Connect

    Roecker, Caleb; Bernstein, Adam; Marleau, Peter; Vetter, Kai

    2016-11-14

    Cosmogenic high-energy neutrons are a ubiquitous, difficult to shield, poorly measured background. Above ground the high-energy neutron energy-dependent flux has been measured, with significantly varying results. Below ground, high-energy neutron fluxes are largely unmeasured. Here we present a reconstruction algorithm to unfold the incident neutron energy-dependent flux measured using the Multiplicity and Recoil Spectrometer (MARS), simulated test cases to verify the algorithm, and provide a new measurement of the above ground high-energy neutron energy-dependent flux with a detailed systematic uncertainty analysis. Uncertainty estimates are provided based upon the measurement statistics, the incident angular distribution, the surrounding environment of the Monte Carlo model, and the MARS triggering efficiency. Quantified systematic uncertainty is dominated by the assumed incident neutron angular distribution and surrounding environment of the Monte Carlo model. The energy-dependent neutron flux between 90 MeV and 400 MeV is reported. Between 90 MeV and 250 MeV the MARS results are comparable to previous Bonner sphere measurements. Over the total energy regime measured, the MARS result are located within the span of previous measurements. Lastly, these results demonstrate the feasibility of future below ground measurements with MARS.

  4. Water corrosion measurements on tungsten irradiated with high energy protons and spallation neutrons

    NASA Astrophysics Data System (ADS)

    Maloy, Stuart A.; Scott Lillard, R.; Sommer, Walter F.; Butt, Darryl P.; Gac, Frank D.; Willcutt, Gordon J.; Louthan, McIntyre R.

    2012-12-01

    A detailed analysis was performed on the degradation of a tungsten target under water cooling while being exposed to a 761 MeV proton beam at an average current of 0.867 mA to a maximum fluence of 1.3 × 1021 protons/cm2. The target consisted of 3 mm diameter tungsten rods arranged in bundles and cooled with deionized water flowing over their length. Degradation of the tungsten was measured through analyzing water resistivity, tungsten concentration in water samples that were taken during irradiation and through dimensional measurements on the rods after irradiation. Chemical analysis of irradiated water samples showed W concentrations up to 35 μg/ml. Gamma analysis showed increases in concentrations of many isotopes including W-178, Lu-171, Tm-167, Tm-166, Yb-169 and Hf-175. Dimensional measurements performed after irradiation on the W rods revealed a decrease in diameter as a function of position that followed closely the Gaussian proton beam profile along the rod length and indicated a definite beam-effect. A general decrease in diameter, especially on the coolant-water entrance point where turbulent flow was likely, also suggests a chemically and mechanically-driven corrosion effect. A method to estimate the apparent corrosion rate based on proton fluence is presented and application of this method estimates the material loss rate at about 1.9 W atoms/incident proton. From this result, the corrosion rate of tungsten in a 761 MeV, 0.867 mA proton beam was calculated to be 0.073 cm/full power year. of irradiation.

  5. Spallation radiation effects in materials

    SciTech Connect

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

    1996-06-01

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

  6. Spallation neutron source target station issues

    SciTech Connect

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

    1996-10-01

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

  7. The high-strain-rate and spallation response of tantalum, Ta-10W, and T-111

    SciTech Connect

    Gray, G.T. III; Rollett, A.D.

    1991-01-01

    The compressive true stress-true response of tantalum, Ta-10W, and T-111 were found to depend on the applied strain rate, in the range 0.001 to 7000 s{sup {minus}1}. The strain-rate sensitivities of the flow stress of tantalum, Ta-10W, and T-111 a 1% strain are 0.062, 0.031, and 0.024, respectively. The rates of strain hardening in Tantalum, Ta-10W, and T-111 are seen to exhibit differing behavior with increasing strain rate. The calculated average strain-hardening rate in tantalum, {Theta}, for the quasi-static (0.001 s{sup {minus}1}) data at 25{degrees}C is 2080 MPa/unit strain. The hardening rate at 3000s{sup {minus}1} at 25{degrees}C decreases to 846 MPa/unit strain. Normalizing the work hardening rate in tantalum with the Taylor Factor for a random polycrystal, ({Theta} / (3.07){sup 2}), yields work hardening rates of {mu}/276 at quasi-static strain rates and {mu}/680 at high-rates, assuming a shear modulus of 61 GPa for tantalum at room temperature. While the work hardening of all the tantalum-based materials are similar at quasi-static rates, alloying results in a small reduction in hardening rate. With increasing strain rate, the work hardening rate in tantalum decreases by approximately a factor of two compared to the alloys. Alloying tantalum with substitutional or interstitial elements is thought to result in increased edge dislocation storage and screw dislocation cross-slip due to interactions with the alloying elements at high strain rates. 28 refs.

  8. Production of ACTINIUM-225 via High Energy Proton Induced Spallation of THORIUM-232

    NASA Astrophysics Data System (ADS)

    Harvey, James; Nolen, Jerry A.; Kroc, Thomas; Gomes, Itacil; Horwitz, E. Philip.; McAlister, Daniel R.

    2010-06-01

    The science of cancer research is currently expanding its use of alpha particle emitting radioisotopes. Coupled with the discovery and proliferation of molecular species that seek out and attach to tumors, new therapy and diagnostics are being developed to enhance the treatment of cancer and other diseases. This latest technology is commonly referred to as Alpha Immunotherapy (AIT). Actinium-225/Bismuth-213 is a parent/daughter alpha-emitting radioisotope pair that is highly sought after because of the potential for treating numerous diseases and its ability to be chemically compatible with many known and widely used carrier molecules (such as monoclonal antibodies and proteins/peptides). The object of this effort is to refine the simulations for producing actinium-225 at proton beam energies of 400 MeV and above up to about 8 GeV. Once completed, the simulations will be experimentally verified using 400 MeV and 8 GeV protons available at Fermi National Accelerator Laboratory. Targets will be processed at Argonne National Laboratory to separate and purify the actinium-225 that will subsequently be transferred to NorthStar laboratory facilities for product quality testing and comparison to the product quality of ORNL produced actinium-225, which is currently the industry standard. The test irradiations at FNAL will produce 1-20 mCi per day which is more than sufficient for quantitative evaluation of the proposed production process.

  9. The European scene regarding spallation neutron sources

    SciTech Connect

    Bauer, G.S.

    1996-06-01

    In Europe, a short pulse spallation neutron source, ISIS, has been operating for over 10 years, working its way up to a beam power level of 200 kW. A continuous source, SINQ, designed for a beam power of up to 1 MW, is scheduled to start operating at the end of 1996, and a detailed feasibility study has been completed for a 410 kW short pulse source, AUSTRON. Each of these sources seems to have settled for a target concept which is at or near the limits of its feasibility: The ISIS depleted uranium plate targets, heavy water cooled and Zircaloy clad, have so far not shown satisfactory service time and operation is likely to continue with a Ta-plate target, which, in the past has been used successfully for the equivalent of one full-beam-year before it was taken out of service due to degrading thermal properties. SINQ will initially use a rod target, made of Zircaloy only, but plans exist to move on to clad lead rods as quickly as possible. Apart from the not yet explored effect of hydrogen and helium production, there are also concerns about the generation of 7-Be in the cooling water from the spallation of oxygen, which might result in undesirably high radioactivity in the cooling plant room. A Liquid metal target, also under investigation for SINQ, would not only reduce this problem to a level of about 10 %, but would also minimize the risk of radiolytic corrosion in the beam interaction zone. Base on similar arguments, AUSTRON has been designed for edge cooled targets, but thermal and stress analyses show, that this concept is not feasible at higher power levels.

  10. PERFORMING DIAGNOSTICS ON THE SPALLATION NEUTRON SOURCE VISION BEAM LINE TO ELIMINATE HIGH VIBRATION LEVELS AND PROVIDE A SUSTAINABLE OPERATION

    SciTech Connect

    Van Hoy, Blake W

    2014-01-01

    The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL) provides variable energy neutrons for a variety of experiments. The neutrons proceed down beam lines to the experiment hall, which houses a variety of experiments and test articles. Each beam line has one or more neutron choppers which filter the neutron beam based on the neutron energy by using a rotating neutron absorbing material passing through the neutron beam. Excessive vibration of the Vision beam line, believed to be caused by the T0 chopper, prevented the Vision beam line from operating at full capacity. This problem had been addressed several times by rebalancing/reworking the T0 beam chopper but the problem stubbornly persisted. To determine the cause of the high vibration, dynamic testing was performed. Twenty-seven accelerometer and motor current channels of data were collected during drive up, drive down, coast down, and steady-state conditions; resonance testing and motor current signature analysis were also performed. The data was analyzed for traditional mechanical/machinery issues such as misalignment and imbalance using time series analysis, frequency domain analysis, and operating deflection shape analysis. The analysis showed that the chopper base plate was experiencing an amplified response to the excitation provided by the T0 beam chopper. The amplified response was diagnosed to be caused by higher than expected base plate flexibility, possibly due to improper grouting or loose floor anchors. Based on this diagnosis, a decision was made to dismantle the beam line chopper and remount the base plate. Neutron activation of the beam line components make modifications to the beam line especially expensive and time consuming due to the radiation handling requirements, so this decision had significant financial and schedule implications. It was found that the base plate was indeed loose because of improper grouting during its initial installation. The base plate was

  11. HPC simulations of grain-scale spallation to improve thermal spallation drilling

    NASA Astrophysics Data System (ADS)

    Walsh, S. D.; Lomov, I.; Wideman, T. W.; Potter, J.

    2012-12-01

    Thermal spallation drilling and related hard-rock hole opening techniques are transformative technologies with the potential to dramatically reduce the costs associated with EGS well drilling and improve the productivity of new and existing wells. In contrast to conventional drilling methods that employ mechanical means to penetrate rock, thermal spallation methods fragment rock into small pieces ("spalls") without contact via the rapid transmission of heat to the rock surface. State-of-the-art constitutive models of thermal spallation employ Weibull statistical failure theory to represent the relationship between rock heterogeneity and its propensity to produce spalls when heat is applied to the rock surface. These models have been successfully used to predict such factors as penetration rate, spall-size distribution and borehole radius from drilling jet velocity and applied heat flux. A properly calibrated Weibull model would permit design optimization of thermal spallation drilling under geothermal field conditions. However, although useful for predicting system response in a given context, Weibull models are by their nature empirically derived. In the past, the parameters used in these models were carefully determined from laboratory tests, and thus model applicability was limited by experimental scope. This becomes problematic, for example, if simulating spall production at depths relevant for geothermal energy production, or modeling thermal spallation drilling in new rock types. Nevertheless, with sufficient computational resources, Weibull models could be validated in the absence of experimental data by explicit small-scale simulations that fully resolve rock grains. This presentation will discuss how high-fidelity simulations can be used to inform Weibull models of thermal spallation, and what these simulations reveal about the processes driving spallation at the grain-scale - in particular, the role that inter-grain boundaries and micro-pores play in the

  12. 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.

  13. NOBLE GAS PRODUCTION FROM MERCURY SPALLATION AT SNS

    SciTech Connect

    DeVore, Joe R; Lu, Wei; Schwahn, Scott O

    2013-01-01

    Calculations for predicting the distribution of the products of spallation reactions between high energy protons and target materials are well developed and are used for design and operational applications in many projects both within DOE and in other arenas. These calculations are based on theory and limited experimental data that verifies rates of production of some spallation products exist. At the Spallation Neutron Source, a helium stream from the mercury target flows through a system to remove radioactivity from this mercury target offgas. The operation of this system offers a window through which the production of noble gases from mercury spallation by protons may be observed. This paper describes studies designed to measure the production rates of twelve noble gas isotopes within the Spallation Neutron Source mercury target.

  14. High Power Hall Thrusters

    NASA Technical Reports Server (NTRS)

    Jankovsky, Robert; Tverdokhlebov, Sergery; Manzella, David

    1999-01-01

    The development of Hall thrusters with powers ranging from tens of kilowatts to in excess of one hundred kilowatts is considered based on renewed interest in high power. high thrust electric propulsion applications. An approach to develop such thrusters based on previous experience is discussed. It is shown that the previous experimental data taken with thrusters of 10 kW input power and less can be used. Potential mass savings due to the design of high power Hall thrusters are discussed. Both xenon and alternate thruster propellant are considered, as are technological issues that will challenge the design of high power Hall thrusters. Finally, the implications of such a development effort with regard to ground testing and spacecraft intecrati'on issues are discussed.

  15. CSTI high capacity power

    SciTech Connect

    Winter, J.M.

    1994-09-01

    The SP-100 program was established in 1983 by DOD, DOE, and NASA as a joint program to develop the technology necessary for space nuclear power systems for military and civil application. During FY86 and 87, the NASA SP-100 Advanced Technology Program was devised to maintain the momentum of promising technology advancement efforts started during Phase I of SP-100 and to strengthen, in key areas, the chances for successful development and growth capability of space nuclear reactor power systems for future space applications. In FY88, the Advanced Technology Program was incorporated into NASA`s new Civil Space Technology Initiative (CSTI). The CSTI Program was established to provide the foundation for technology development in automation and robotics, information, propulsion, and power. The CSTI High Capacity Power Program builds on the technology efforts of the SP-100 program, incorporates the previous NASA SP-100 Advanced Technology project, and provides a bridge to NASA Project Pathfinder. The elements of CSTI High Capacity Power development include Conversion Systems, Thermal Management, Power Management, System Diagnostics, and Environmental Interactions. Technology advancement in all areas, including materials, is required to assure the high reliability and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall program will develop and demonstrate the technology base required to provide a wide range of modular power systems as well as allowing mission independence from solar and orbital attitude requirements. Several recent advancements in CSTI High Capacity power development will be discussed.

  16. CSTI High Capacity Power

    NASA Technical Reports Server (NTRS)

    Winter, Jerry M.

    1989-01-01

    The SP-100 program was established in 1983 by DOD, DOE, and NASA as a joint program to develop the technology necessary for space nuclear power systems for military and civil application. During FY-86 and 87, the NASA SP-100 Advanced Technology Program was devised to maintain the momentum of promising technology advancement efforts started during Phase 1 of SP-100 and to strengthen, in key areas, the chances for successful development and growth capability of space nuclear reactor power systems for future space applications. In FY-88, the Advanced Technology Program was incorporated into NASA's new Civil Space Technology Initiative (CSTI). The CSTI Program was established to provide the foundation for technology development in automation and robotics, information, propulsion, and power. The CSTI High Capacity Power Program builds on the technology efforts of the SP-100 program, incorporates the previous NASA SP-100 Advanced Technology project, and provides a bridge to NASA Project Pathfinder. The elements of CSTI High Capacity Power development include Conversion Systems, Thermal Management, Power Management, System Diagnostics, and Environmental Interactions. Technology advancement in all areas, including materials, is required to assure the high reliability and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall program will develop and demonstrate the technology base required to provide a wide range of modular power systems as well as allowing mission independence from solar and orbital attitude requirements. Several recent advancements in CSTI High Capacity power development will be discussed.

  17. Characteristics of high-energy neutrons estimated using the radioactive spallation products of Au at the 500-MeV neutron irradiation facility of KENS.

    PubMed

    Matsumura, Hiroshi; Masumoto, Kazuyoshi; Nakao, Noriaki; Wang, Qingbin; Toyoda, Akihiro; Kawai, Masayoshi; Aze, Takahiro; Fujimura, Masatsugu

    2005-01-01

    We carried out a shielding experiment of high-energy neutrons, generated from a tungsten target bombarded with primary 500-MeV protons at KENS, which penetrated through a concrete shield in the zero-degree direction. We propose a new method to evaluate the spectra of high-energy neutrons ranging from 8 to 500 MeV. Au foils were set in a concrete shield, and the reaction rates for 13 radionuclides produced by the spallation reactions on the Au targets were measured by radiochemical techniques. The experimental results were compared with those obtained by the MARS14 Monte-Carlo code. A good agreement (between them) was found for energies beyond 100 MeV. The profile of the neutron spectrum, ranging from 8 to 500 MeV, does not depend on the thickness of the concrete shield.

  18. The European Spallation Source

    SciTech Connect

    Peggs, S; Eshraqi, M; Hahn, H; Jansson, A; Lindroos, M; Ponton, A; Rathsman, K; Trahern, G; Bousso, S; Calaga, R; Devanz, G; Duperrier, R D; Eguia, J; Gammino, S; Moller, S P; Oyon, C; Ruber, R.J.M.Y.; Satogata, T

    2011-03-01

    The European Spallation Source (ESS) is a 5 MW, 2.5 GeV long pulse proton linac, to be built and commissioned in Lund, Sweden. The Accelerator Design Update (ADU) project phase is under way, to be completed at the end of 2012 by the delivery of a Technical Design Report. Improvements to the 2003 ESS design will be summarised, and the latest design activities will be presented.

  19. Post-irradiation examination of the Spallation Neutron Source target module

    NASA Astrophysics Data System (ADS)

    McClintock, D. A.; Ferguson, P. D.; Mansur, L. K.

    2010-03-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is an accelerator-based pulsed neutron source that produces high-energy spallation neutrons by bombarding liquid mercury flowing through a stainless steel target vessel. During operation the proton beam and spallation neutrons produce radiation damage in the AISI 316L austenitic stainless steel target vessel and water-cooled shroud. The beam pulses also cause rapid heating of the liquid mercury, which may produce cavitation erosion damage on the inner surface of the target vessel. The cavitation erosion rate is thought to be highly sensitive to beam power and predicted to be the primary life-limiting factor of the target module. Though cavitation erosion and radiation damage to the target vessel are expected to dictate its lifetime, the effects of radiation damage and cavitation erosion to target vessels in liquid metal spallation systems are not well known. Therefore preparations are being undertaken to perform post-irradiation examination (PIE) of the liquid mercury target vessel and water-cooled shroud after end-of-life occurs. An overview of the planned PIE for the SNS target vessel is presented here, including proposed techniques for specimen acquisition and subsequent material properties characterization.

  20. STATUS OF THE SPALLATION NEUTRON SOURCE SUPERCONDUCTING RF FACILITIES

    SciTech Connect

    Stout, Daniel S; Assadi, Saeed; Campisi, Isidoro E; Casagrande, Fabio; Crofford, Mark T; DeVan, Bill; Hardek, Thomas W; Henderson, Stuart D; Howell, Matthew P; Kang, Yoon W; Geng, Xiaosong; Stone Jr, William C; Strong, William Herb; Williams, Derrick C; Wright, Paul Alan

    2007-01-01

    The Spallation Neutron Source (SNS) project was completed with only limited superconducting RF (SRF) facilities installed as part of the project. A concerted effort has been initiated to install the infrastructure and equipment necessary to maintain and repair the superconducting Linac, and to support power upgrade research and development (R&D). Installation of a Class10/100/10,000 cleanroom and outfitting of the test cave with RF, vacuum, controls, personnel protection and cryogenics systems is underway. A horizontal cryostat, which can house a helium vessel/cavity and fundamental power coupler for full power, pulsed testing, is being procured. Equipment for cryomodule assembly and disassembly is being procured. This effort, while derived from the experience of the SRF community, will provide a unique high power test capability as well as long term maintenance capabilities. This paper presents the current status and the future plans for the SNS SRF facilities.

  1. High power microwave generator

    DOEpatents

    Ekdahl, Carl A.

    1986-01-01

    A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

  2. High power microwave generator

    DOEpatents

    Ekdahl, C.A.

    1983-12-29

    A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

  3. The European Spallation Source

    SciTech Connect

    Lindroos M.; Calaga R.; Bousson S.; Danared H.; Devanz G. et al

    2011-04-20

    In 2003 the joint European effort to design a European Spallation Source (ESS) resulted in a set of reports, and in May 2009 Lund was agreed to be the ESS site. The ESS Scandinavia office has since then worked on setting all the necessary legal and organizational matters in place so that the Design Update and construction can be started in January 2011, in collaboration with European partners. The Design Update phase is expected to end in 2012, to be followed by a construction phase, with first neutrons expected in 2018-2019.

  4. High power density targets

    NASA Astrophysics Data System (ADS)

    Pellemoine, Frederique

    2013-12-01

    In the context of new generation rare isotope beam facilities based on high-power heavy-ion accelerators and in-flight separation of the reaction products, the design of the rare isotope production targets is a major challenge. In order to provide high-purity beams for science, high resolution is required in the rare isotope separation. This demands a small beam spot on the production target which, together with the short range of heavy ions in matter, leads to very high power densities inside the target material. This paper gives an overview of the challenges associated with this high power density, discusses radiation damage issues in targets exposed to heavy ion beams, and presents recent developments to meet some of these challenges through different projects: FAIR, RIBF and FRIB which is the most challenging. Extensive use of Finite Element Analysis (FEA) has been made at all facilities to specify critical target parameters and R&D work at FRIB successfully retired two major risks related to high-power density and heavy-ion induced radiation damage.

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

    SciTech Connect

    WEI,J.

    2006-09-21

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

  6. High Current Power Controller

    DTIC Science & Technology

    1981-04-01

    AFWAL-TR-81- 2016 U iui.N HIGH CURRENT Ŕ POWER CONTROLLER P. E. McCOLLUM Audwo ROCKWELL INTERNATIONAL AUTONETICS STRATEGIC SYSTEMS DIVISION 3370...personnel. During norm3l operation, HCP \\.s pose no hazard, bLt unde- certain operating conditions potential noaza-ds do exist. They are: (1) During

  7. High Power Cryogenic Targets

    SciTech Connect

    Gregory Smith

    2011-08-01

    The development of high power cryogenic targets for use in parity violating electron scattering has been a crucial ingredient in the success of those experiments. As we chase the precision frontier, the demands and requirements for these targets have grown accordingly. We discuss the state of the art, and describe recent developments and strategies in the design of the next generation of these targets.

  8. High power arcjet

    NASA Technical Reports Server (NTRS)

    Goelz, T. M.; Auweter-Kurtz, M.; Kurtz, H. L.; Schrade, H. O.

    1991-01-01

    The activities of the High Power Arcjet Project (HIPARC) from August 1990 to January 1991 are discussed. In this period the HIPARC thruster was ignited for the first time. Power levels up to 140 kW with a mass flow rate of 300 mg/s hydrogen were reached. Specific impulse values of more than 1300 s were shown to be possible. Tests were performed with the baseline thruster version only, which has a 6 mm throat diameter and a conical nozzle with a 20 degree half angle. Measurement data summing up all tests carried out until now is included. All measuring methods are described, including a check on possible error sources.

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

    SciTech Connect

    Carpenter, J. M.

    2002-12-04

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

  10. BEAM INSTRUMENTATION FOR THE SPALLATION NEUTRON SOURCE RING.

    SciTech Connect

    WITKOVER,R.L.; CAMERON,P.R.; SHEA,T.J.; CONNOLLY,R.C.; KESSELMAN,M.

    1999-03-29

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

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

    SciTech Connect

    WEI,J.

    2004-07-05

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

  12. High power connection system

    DOEpatents

    Schaefer, Christopher E.; Beer, Robert C.; McCall, Mark D.

    2000-01-01

    A high power connection system adapted for automotive environments which provides environmental and EMI shielding includes a female connector, a male connector, and a panel mount. The female connector includes a female connector base and a snap fitted female connector cover. The male connector includes a male connector base and a snap fitted male connector cover. The female connector base has at least one female power terminal cavity for seatably receiving a respective female power terminal. The male connector base has at least one male power terminal cavity for seatably receiving a respective male power terminal. The female connector is covered by a cover seal and a conductive shroud. A pair of lock arms protrude outward from the front end of the male connector base, pass through the panel mount and interface with a lever of a lever rotatably connected to the shroud to thereby mechanically assist mating of the male and female connectors. Safety terminals in the male and female connectors provide a last-to-connect-first-to-break connection with an HVIL circuit.

  13. High Power Switching Transistor

    NASA Technical Reports Server (NTRS)

    Hower, P. L.; Kao, Y. C.; Carnahan, D. C.

    1983-01-01

    Improved switching transistors handle 400-A peak currents and up to 1,200 V. Using large diameter silicon wafers with twice effective area as D60T, form basis for D7 family of power switching transistors. Package includes npn wafer, emitter preform, and base-contact insert. Applications are: 25to 50-kilowatt high-frequency dc/dc inverters, VSCF converters, and motor controllers for electrical vehicles.

  14. High power arcjet

    NASA Technical Reports Server (NTRS)

    Auweter-Kurtz, M.; Glocker, B.; Goelz, T. M.; Habiger, H.; Kurtz, H. L.; Schrade, H. O.; Wegmann, T.

    1990-01-01

    The activities on the development of the high power arc jet HIPARC, the thrust balance, and plasma diagnostic probes are discussed. Modifications of the HIPARC design and a synopsis of the materials used are given. Further experimental results with the TT30 thruster in the 50 kW range are presented. Some first calibration measurements of the thrust balance are also included. Progress concerning the development of plasma diagnostic devices is documented.

  15. High Power Modulator.

    DTIC Science & Technology

    1986-08-01

    The bushing consists of three segments of alumina tubing with interspersed metal rings. All metallic surfaces ex- *posed to vacuum are stainless steel...high voltage transient only lasted for several hundred ns, no vacuum insulator breakdown was noted during the tests. 4.2 Acceptance tests at PSI The...ation at 1 pps. The oil insulated output pulse transformer has multiple secondary windings which can be used to provide heater power for a thermionic

  16. Mercury Cavitation Phenomenon in Pulsed Spallation Neutron Sources

    SciTech Connect

    Futakawa, Masatoshi; Naoe, Takashi; Kawai, Masayoshi

    2008-06-24

    Innovative researches will be performed at Materials and Life Science Experimental Facility in J-PARC, in which a mercury target system will be installed as MW-class pulse spallation neutron sources. Proton beams will be injected into mercury target to induce the spallation reaction. At the moment the intense proton beam hits the target, pressure waves are generated in the mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel leading to negative pressure that may cause cavitation along the vessel wall. Localized impacts by micro-jets and/or shock waves which are caused by cavitation bubble collapse impose pitting damage on the vessel wall. The pitting damage which degrades the structural integrity of target vessels is a crucial issue for high power mercury targets. Micro-gas-bubbles injection into mercury may be useful to mitigate the pressure wave and the pitting damage. The visualization of cavitation-bubble and gas-bubble collapse behaviors was carried out by using a high-speed video camera. The differences between them are recognized.

  17. HEIMDAL: A thermal neutron powder diffractometer with high and flexible resolution combined with SANS and neutron imaging - Designed for materials science studies at the European Spallation Source

    NASA Astrophysics Data System (ADS)

    Holm, Sonja L.; Lefmann, Kim; Henry, Paul F.; Bertelsen, Mads; Schefer, Jürg; Christensen, Mogens

    2016-08-01

    HEIMDAL will be a multi length scale neutron scattering instrument for the study of structures covering almost nine orders of magnitude from 0.01 nm to 50 mm. The instrument is accepted for construction at the European Spallation Source (ESS) and features a variable resolution thermal neutron powder diffractometer (TNPD), combined with small angle neutron scattering (SANS) and neutron imaging (NI). The instrument uses a novel combination of a cold and a thermal guide to fulfill the diverse requirements for diffraction and SANS. With an instrument length of 170 m, HEIMDAL will take advantage of the high neutron flux of the long pulse at ESS, whilst maintaining a high q-resolution due to the long flight path. The q-range coverage is up to 20 Å-1 allowing low-resolution PDF analysis. With the addition of SANS, HEIMDAL will be able to cover a uniquely broad length scale within a single instrumental set-up. HEIMDAL will be able to accommodate modern materials research in a broad variety of fields, and the task of the instrument will be to study advanced functional materials in action, as in situ and in operandi at multiple length scales (0.01-100 nm) quasi simultaneously. The instrument combines state-of-the-art neutron scattering techniques (TNPD, SANS, and NI) with the goal of studying real materials, in real time, under real conditions. This article describes the instrument design ideas, calculations and results of simulations and virtual experiments.

  18. The thermal spallation drilling process

    SciTech Connect

    Williams, R.E.

    1986-01-01

    Holes can be produced in very hard rock more easily and less expensively by thermal spallation than by conventional means. This drilling process has been used for producing blast holes in the taconite iron mines and for quarrying granite. It is potentially valuable for drilling holes in very hard rock for the exploitation of geothermal energy and the storage of various commodities. However, investigation and development of the thermal spallation drilling process is proceeding slowly.

  19. INJECTION CHOICE FOR SPALLATION NEUTRON SOURCE RING.

    SciTech Connect

    WEI,J.; BEEBE-WANG,J.; BLASKIEWICZ,M.; BRODOWSKI,J.; FEDOTOV,A.; GARDNER,C.; LEE,Y.Y.; RAPARIA,D.; DANILOV,V.; HOLMES,J.; PRIOR,C.; REES,G.; MACHIDA,S.

    2001-06-18

    Injection is key in the low-loss design of high-intensity proton facilities like the Spallation Neutron Source (SNS). During the design of both the accumulator and the rapid-cycling-synchrotron version of the SNS, extensive comparison has been made to select injection scenarios that satisfy SNS's low-loss design criteria. This paper presents issues and considerations pertaining to the final choice of the SNS injection systems.

  20. High voltage power supply

    NASA Technical Reports Server (NTRS)

    Ruitberg, A. P.; Young, K. M. (Inventor)

    1985-01-01

    A high voltage power supply is formed by three discrete circuits energized by a battery to provide a plurality of concurrent output signals floating at a high output voltage on the order of several tens of kilovolts. In the first two circuits, the regulator stages are pulse width modulated and include adjustable ressistances for varying the duty cycles of pulse trains provided to corresponding oscillator stages while the third regulator stage includes an adjustable resistance for varying the amplitude of a steady signal provided to a third oscillator stage. In the first circuit, the oscillator, formed by a constant current drive network and a tuned resonant network included a step up transformer, is coupled to a second step up transformer which, in turn, supplies an amplified sinusoidal signal to a parallel pair of complementary poled rectifying, voltage multiplier stages to generate the high output voltage.

  1. HIGH POWER PULSED OSCILLATOR

    DOEpatents

    Singer, S.; Neher, L.K.

    1957-09-24

    A high powered, radio frequency pulse oscillator is described for generating trains of oscillations at the instant an input direct voltage is impressed, or immediately upon application of a light pulse. In one embodiment, the pulse oscillator comprises a photo-multiplier tube with the cathode connected to the first dynode by means of a resistor, and adjacent dynodes are connected to each other through adjustable resistors. The ohmage of the resistors progressively increases from a very low value for resistors adjacent the cathode to a high value adjacent the plate, the last dynode. Oscillation occurs with this circuit when a high negative voltage pulse is applied to the cathode and the photo cathode is bombarded. Another embodiment adds capacitors at the resistor connection points of the above circuit to increase the duration of the oscillator train.

  2. High Power Density Motors

    NASA Technical Reports Server (NTRS)

    Kascak, Daniel J.

    2004-01-01

    With the growing concerns of global warming, the need for pollution-free vehicles is ever increasing. Pollution-free flight is one of NASA's goals for the 21" Century. , One method of approaching that goal is hydrogen-fueled aircraft that use fuel cells or turbo- generators to develop electric power that can drive electric motors that turn the aircraft's propulsive fans or propellers. Hydrogen fuel would likely be carried as a liquid, stored in tanks at its boiling point of 20.5 K (-422.5 F). Conventional electric motors, however, are far too heavy (for a given horsepower) to use on aircraft. Fortunately the liquid hydrogen fuel can provide essentially free refrigeration that can be used to cool the windings of motors before the hydrogen is used for fuel. Either High Temperature Superconductors (HTS) or high purity metals such as copper or aluminum may be used in the motor windings. Superconductors have essentially zero electrical resistance to steady current. The electrical resistance of high purity aluminum or copper near liquid hydrogen temperature can be l/lOO* or less of the room temperature resistance. These conductors could provide higher motor efficiency than normal room-temperature motors achieve. But much more importantly, these conductors can carry ten to a hundred times more current than copper conductors do in normal motors operating at room temperature. This is a consequence of the low electrical resistance and of good heat transfer coefficients in boiling LH2. Thus the conductors can produce higher magnetic field strengths and consequently higher motor torque and power. Designs, analysis and actual cryogenic motor tests show that such cryogenic motors could produce three or more times as much power per unit weight as turbine engines can, whereas conventional motors produce only 1/5 as much power per weight as turbine engines. This summer work has been done with Litz wire to maximize the current density. The current is limited by the amount of heat it

  3. High power microwave generator

    DOEpatents

    Minich, Roger W.

    1988-01-01

    A device (10) for producing high-powered and coherent microwaves is described. The device comprises an evacuated, cylindrical, and hollow real cathode (20) that is driven to inwardly field emit relativistic electrons. The electrons pass through an internally disposed cylindrical and substantially electron-transparent cylindrical anode (24), proceed toward a cylindrical electron collector electrode (26), and form a cylindrical virtual cathode (32). Microwaves are produced by spatial and temporal oscillations of the cylindrical virtual cathode (32), and by electrons that reflex back and forth between the cylindrical virtual cathode (32) and the cylindrical real cathode (20).

  4. High Power Coax Window

    SciTech Connect

    Neubauer, M. L.; Dudas, A.; Sah, R.; Elliott, T. S.; Rimmer, R. A.; Stirbet, M. S.

    2010-05-23

    A su­per­con­duct­ing RF (SRF) power cou­pler ca­pa­ble of han­dling 500 kW CW RF power is re­quired for pre­sent and fu­ture stor­age rings and linacs. There are over 35 cou­pler de­signs for SRF cav­i­ties rang­ing in fre­quen­cy from 325 to 1500 MHz. Cou­pler win­dows vary from cylin­ders to cones to disks, and RF power cou­plers are lim­it­ed by the abil­i­ty of ce­ram­ic win­dows to with­stand the stress­es due to heat­ing and me­chan­i­cal flex­ure. We pro­pose a novel ro­bust co-ax­i­al SRF cou­pler de­sign which uses com­pressed win­dow tech­nol­o­gy. This tech­nol­o­gy will allow the use of high­ly ther­mal­ly con­duc­tive ma­te­ri­als for cryo­genic win­dows. Using com­pressed win­dow tech­niques on disk co-ax­i­al win­dows will make sig­nif­i­cant im­prove­ments in the power han­dling of SRF cou­plers. We pre­sent the bench test re­sults of two win­dow as­sem­blies back to back, as well as in­di­vid­u­al win­dow VSWR in EIA3.125 coax. A vac­u­um test as­sem­bly was made and the win­dows baked out at 155C. The pro­cess­es used to build win­dows is scal­able to larg­er di­am­e­ter coax and to high­er power lev­els.

  5. High power coaxial ubitron

    NASA Astrophysics Data System (ADS)

    Balkcum, Adam J.

    In the ubitron, also known as the free electron laser, high power coherent radiation is generated from the interaction of an undulating electron beam with an electromagnetic signal and a static periodic magnetic wiggler field. These devices have experimentally produced high power spanning the microwave to x-ray regimes. Potential applications range from microwave radar to the study of solid state material properties. In this dissertation, the efficient production of high power microwaves (HPM) is investigated for a ubitron employing a coaxial circuit and wiggler. Designs for the particular applications of an advanced high gradient linear accelerator driver and a directed energy source are presented. The coaxial ubitron is inherently suited for the production of HPM. It utilizes an annular electron beam to drive the low loss, RF breakdown resistant TE01 mode of a large coaxial circuit. The device's large cross-sectional area greatly reduces RF wall heat loading and the current density loading at the cathode required to produce the moderate energy (500 keV) but high current (1-10 kA) annular electron beam. Focusing and wiggling of the beam is achieved using coaxial annular periodic permanent magnet (PPM) stacks without a solenoidal guide magnetic field. This wiggler configuration is compact, efficient and can propagate the multi-kiloampere electron beams required for many HPM applications. The coaxial PPM ubitron in a traveling wave amplifier, cavity oscillator and klystron configuration is investigated using linear theory and simulation codes. A condition for the dc electron beam stability in the coaxial wiggler is derived and verified using the 2-1/2 dimensional particle-in-cell code, MAGIC. New linear theories for the cavity start-oscillation current and gain in a klystron are derived. A self-consistent nonlinear theory for the ubitron-TWT and a new nonlinear theory for the ubitron oscillator are presented. These form the basis for simulation codes which, along

  6. High power beam analysis

    NASA Astrophysics Data System (ADS)

    Aharon, Oren

    2014-02-01

    In various modern scientific and industrial laser applications, beam-shaping optics manipulates the laser spot size and its intensity distribution. However the designed laser spot frequently deviates from the design goal due to real life imperfections and effects, such as: input laser distortions, optical distortion, heating, overall instabilities, and non-linear effects. Lasers provide the ability to accurately deliver large amounts of energy to a target area with very high accuracy. Thus monitoring beam size power and beam location is of high importance for high quality results and repeatability. Depending on the combination of wavelength, beam size and pulse duration , laser energy is absorbed by the material surface, yielding into processes such as cutting, welding, surface treatment, brazing and many other applications. This article will cover the aspect of laser beam measurements, especially at the focal point where it matters the most. A brief introduction to the material processing interactions will be covered, followed by fundamentals of laser beam propagation, novel measurement techniques, actual measurement and brief conclusions.

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

    SciTech Connect

    Robert Rimmer, Frank Marhauser

    2009-05-01

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

  8. High power, high frequency component test facility

    NASA Technical Reports Server (NTRS)

    Roth, Mary Ellen; Krawczonek, Walter

    1990-01-01

    The NASA Lewis Research Center has available a high frequency, high power laboratory facility for testing various components of aerospace and/or terrestrial power systems. This facility is described here. All of its capabilities and potential applications are detailed.

  9. Spallation neutron source saddle antenna H{sup -} ion source project

    SciTech Connect

    Dudnikov, Vadim; Johnson, Rolland P.; Dudnikova, Galina; Stockli, Martin; Welton, Robert

    2010-02-15

    In this project we are developing an H{sup -} source which will synthesize the most important developments in the field of negative ion sources to provide high current, high brightness, good lifetime, high reliability, and high power efficiency. We describe two planned modifications to the present spallation neutron source external antenna source in order to increase the plasma density near the output aperture: (1) replacing the present 2 MHz plasma-forming solenoid antenna with a 13 MHz saddle-type antenna and (2) replacing the permanent multicusp magnetic system with a weaker electromagnet.

  10. Simulation of a beam rotation system for a spallation source

    NASA Astrophysics Data System (ADS)

    Reiss, Tibor; Reggiani, Davide; Seidel, Mike; Talanov, Vadim; Wohlmuther, Michael

    2015-04-01

    With a nominal beam power of nearly 1 MW on target, the Swiss Spallation Neutron Source (SINQ), ranks among the world's most powerful spallation neutron sources. The proton beam transport to the SINQ target is carried out exclusively by means of linear magnetic elements. In the transport line to SINQ the beam is scattered in two meson production targets and as a consequence, at the SINQ target entrance the beam shape can be described by Gaussian distributions in transverse x and y directions with tails cut short by collimators. This leads to a highly nonuniform power distribution inside the SINQ target, giving rise to thermal and mechanical stresses. In view of a future proton beam intensity upgrade, the possibility of homogenizing the beam distribution by means of a fast beam rotation system is currently under investigation. Important aspects which need to be studied are the impact of a rotating proton beam on the resulting neutron spectra, spatial flux distributions and additional—previously not present—proton losses causing unwanted activation of accelerator components. Hence a new source description method was developed for the radiation transport code MCNPX. This new feature makes direct use of the results from the proton beam optics code TURTLE. Its advantage to existing MCNPX source options is that all phase space information and correlations of each primary beam particle computed with TURTLE are preserved and transferred to MCNPX. Simulations of the different beam distributions together with their consequences in terms of neutron production are presented in this publication. Additionally, a detailed description of the coupling method between TURTLE and MCNPX is provided.

  11. Spallation source materials test program

    SciTech Connect

    Maloy, S.A.; Sommer, W.F.

    1997-12-01

    A spallation source materials program has been developed to irradiate and test candidate materials (Inconel 718, 316L and 304L stainless steel, modified 9Cr-1Mo(T91), Al6061-T6, Al5052-O) for use in the Accelerator Production of Tritium (APT) target and blanket in prototypic proton and neutron fluxes at prototypic temperatures. The study uses the 800 MeV, 1mA proton accelerator at the Los Alamos Neutron Science Center (LANSCE) which produces a Gaussian beam with 2 sigma = 3 cm. The experimental set-up contains prototypic modules of the tungsten neutron source and the lead/aluminum blanket with mechanical testing specimens of candidate APT materials placed in specific locations in the irradiation area. These specimens have been irradiated for greater than 3,600 hours with a maximum proton fluence of 4--5 {times} 10{sup 21} p/cm{sup 2} in the center of the proton beam. Specimens will yield some of the first data on the effect of proton irradiation to high dose on the materials` properties from tensile tests, 3 pt. bend tests, fracture toughness tests, pressurized tubes, U-bend stress corrosion cracking specimens, corrosion measurements and microstructural characterization of transmission electron microscopy specimens.

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

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

    The China Spallation Neutron Source (CSNS) is an accelerator based multidiscipline user facility planned to be constructed in Dongguan, Guangdong, China. The CSNS complex consists of an negative hydrogen linear accelerator, a rapid cycling proton synchrotron accelerating the beam to 1.6 GeV energy, a solid tungsten target station, and instruments for spallation neutron applications. The facility operates at 25 Hz repetition rate with an initial design beam power of 120 kW and is upgradeable to 500 kW. The primary challenge is to build a robust and reliable user's facility with upgrade potential at a fraction of "world standard" cost. We report the status, design, R&D, and upgrade outlook including applications using spallation neutron, muon, fast neutron, and proton, as well as related programs including medical therapy and accelerator-driven sub-critical reactor (ADS) programs for nuclear waste transmutation.

  13. High-Efficiency Power Module

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N. (Inventor); Wintucky, Edwin G. (Inventor)

    2015-01-01

    One or more embodiments of the present invention pertain to an all solid-state microwave power module. The module includes a plurality of solid-state amplifiers configured to amplify a signal using a low power stage, a medium power stage, and a high power stage. The module also includes a power conditioner configured to activate a voltage sequencer (e.g., bias controller) when power is received from a power source. The voltage sequencer is configured to sequentially apply voltage to a gate of each amplifier and sequentially apply voltage to a drain of each amplifier.

  14. High-Efficiency Power Module

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N (Inventor); Wintucky, Edwin G (Inventor)

    2013-01-01

    One or more embodiments of the present invention pertain to an all solid-state microwave power module. The module includes a plurality of solid-state amplifiers configured to amplify a signal using a low power stage, a medium power stage, and a high power stage. The module also includes a power conditioner configured to activate a voltage sequencer (e.g., bias controller) when power is received from a power source. The voltage sequencer is configured to sequentially apply voltage to a gate of each amplifier and sequentially apply voltage to a drain of each amplifier.

  15. High power phase shifter

    SciTech Connect

    Foster, B.; Gonin, I.; Khabiboulline, T.; Makarov, A.; Solyak, N.; Terechkine, I.; Wildman, D.; /Fermilab

    2005-05-01

    One of the approaches to power distribution system of a superconducting proton linac under discussion at FNAL requires development of a fast-action, megawatt-range phase shifter. Using a couple of this kind of devices with a waveguide hybrid junction can allow independent control of phase and amplitude of RF power at the input of each superconducting cavity, which will result in significant saving in number of klystrons and modulators required for the accelerator. A prototype of a waveguide version of the shifter that uses Yttrium-Iron Garnet (YIG) blocks was developed and tested. This report presents design concept of the device, and main results of simulation and proof-of-principle tests.

  16. Modeling of water radiolysis at spallation neutron sources

    SciTech Connect

    Daemen, L.L.; Kanner, G.S.; Lillard, R.S.; Butt, D.P.; Brun, T.O.; Sommer, W.F.

    1998-12-01

    In spallation neutron sources neutrons are produced when a beam of high-energy particles (e.g., 1 GeV protons) collides with a (water-cooled) heavy metal target such as tungsten. The resulting spallation reactions produce a complex radiation environment (which differs from typical conditions at fission and fusion reactors) leading to the radiolysis of water molecules. Most water radiolysis products are short-lived but extremely reactive. When formed in the vicinity of the target surface they can react with metal atoms, thereby contributing to target corrosion. The authors describe the results of calculations and experiments performed at los alamos to determine the impact on target corrosion of water radiolysis in the spallation radiation environment. The computational methodology relies on the use of the Los Alamos radiation transport code, LAHET, to determine the radiation environment, and the AEA code, FACSIMILE, to model reaction-diffusion processes.

  17. High Power Fiber Lasers

    DTIC Science & Technology

    2012-08-02

    mode, purity of polarization state, minimization of nonlinear effects, compatibility with all-fiber pumps, and high temperature buffer coatings. Over...nonlinear effects, compatibility with all-fiber pumps, and high temperature buffer coatings. Over the duration of this program the most significant...minimization of nonlinear effects, compatibility with all-fiber pumps, and high temperature buffer coatings. Over the duration of this program the most

  18. Materials compatibility studies for the Spallation Neutron Source

    SciTech Connect

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

    1998-11-01

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

  19. High Power Switch Development.

    DTIC Science & Technology

    1979-11-29

    fundamental properties of electron beam triggered LJ switches and determine their capabilities and limitations. 2. Investigate breakdown phenomena at high...discharge is goal have been achieved by laser triggered broad in cross-section. switching 1 (ITS), and by e-beam triggered Voltage, current, and jitter...and J. R. Settis; "The Laser Triggering of High Voltage Switches ". J. , .’-- o, .. Phys. D.: Appl. Phys., Vol. 11, 1577,(1978). c..-- , 2. E. A

  20. TRANSISTOR HIGH VOLTAGE POWER SUPPLY

    DOEpatents

    Driver, G.E.

    1958-07-15

    High voltage, direct current power supplies are described for use with battery powered nuclear detection equipment. The particular advantages of the power supply described, are increased efficiency and reduced size and welght brought about by the use of transistors in the circuit. An important feature resides tn the employment of a pair of transistors in an alternatefiring oscillator circuit having a coupling transformer and other circuit components which are used for interconnecting the various electrodes of the transistors.

  1. High Power Proton Facilities

    NASA Astrophysics Data System (ADS)

    Nagaitsev, Sergei

    2015-04-01

    This presentation will provide an overview of the capabilities and challenges of high intensity proton accelerators, such as J-PARC, Fermilab MI, SNS, ISIS, PSI, ESS (in the future) and others. The presentation will focus on lessons learned, new concepts, beam loss mechanisms and methods to mitigate them.

  2. Status of the AUSTRON spallation project

    NASA Astrophysics Data System (ADS)

    Rauch, H.; Regler, M.; Weber, H.

    2000-03-01

    The characteristic parameters of the present version of the planned AUSTRON neutron spallation source are: (a) 10 Hz repetition rate at the target, (b) 500 kW average beam power, (c) 1.6 GeV proton energy and (d) strongly dedicated to cold neutron research. The machine can be built based on existing techniques and would provide a performance gain between 3 and 10 compared to existing installations. Progress has been made in the planning of the instrumentation where an improved standard instrumentation and several new systems have been designed and evaluated by an international group of neutron scientists. A clean room area with vibration, temperature and humidity control provides new possibilities for neutron optics, neutron reflectometry and nuclear orientation experiments. A proposed magnetic focusing line with an active energy transfer system indicates the capability to achieve a further intensity gain by a factor of 10. The status of the ongoing internationalization process will be reported as well.

  3. Spallation studies on shock loaded uranium

    SciTech Connect

    Tonks, D.L.; Hixson, R.; Gustavsen, R.L.; Vorthman, J.E.; Kelly, A.; Zurek, A.K.; Thissel, W.R.

    1997-12-31

    Uranium samples at two different purity levels were used for spall strength measurements at three different stress levels. A 50 mm single-stage gas-gun was used to produce planar impact conditions using Z-cut quartz impactors. Samples of depleted uranium were taken from very high purity material and from material that had 300 ppm of carbon added. A pair of shots was done for each impact strength, one member of the pair with VISAR diagnostics and the second with soft recovery for metallographical examination. A series of increasing final stress states were chosen to effectively freeze the microstructural damage at three places in the development to full spall separation. This allowed determination of the dependence of spall mechanisms on stress level and sample purity. This report will discuss both the results of the metallurgical examination of soft recovered samples and the modeling of the free surface VISAR data. The micrographs taken from the recovered samples show brittle cracking as the spallation failure mechanism. Deformation induced twins are plentiful and obviously play a role in the spallation process. The twins are produced in the initial shock loading and, so, are present already before the fracture process begins. The 1 d characteristics code CHARADE has been used to model the free surface VISAR data.

  4. Compact High Power THz Source

    SciTech Connect

    Geoffrey Krafft

    2003-08-01

    In this paper a new type of THz radiation source, based on recirculating an electron beam through a high gradient superconducting radio frequency cavity, and using this beam to drive a standard electromagnetic undulator, is discussed. Because the beam is recirculated, short bunches may be produced that radiate coherently in the undulator, yielding high average THz power for relatively low average beam power. Deceleration from the coherent emission, and the detuning it causes is discussed.

  5. High average power pockels cell

    DOEpatents

    Daly, Thomas P.

    1991-01-01

    A high average power pockels cell is disclosed which reduces the effect of thermally induced strains in high average power laser technology. The pockels cell includes an elongated, substantially rectangular crystalline structure formed from a KDP-type material to eliminate shear strains. The X- and Y-axes are oriented substantially perpendicular to the edges of the crystal cross-section and to the C-axis direction of propagation to eliminate shear strains.

  6. High power solid state lasers

    SciTech Connect

    Weber, H.

    1988-01-01

    These proceedings discuss the following subjects: trends in materials processing with laser radiation; slabs and high power systems; glasses and new crystals; solid state lasers at HOYA Corp.; lamps, resonators and transmission; glasses as active materials for high average power solid state lasers; flashlamp pumped GGG-crystals; alexandrite lasers; designing telescope resonators; mode operation of neodymium: YAG lasers; intracavity frequency doubling with KTP crystal and thermal effects in cylinder lasers.

  7. High power ferrite microwave switch

    NASA Technical Reports Server (NTRS)

    Bardash, I.; Roschak, N. K.

    1975-01-01

    A high power ferrite microwave switch was developed along with associated electronic driver circuits for operation in a spaceborne high power microwave transmitter in geostationary orbit. Three units were built and tested in a space environment to demonstrate conformance to the required performance characteristics. Each unit consisted of an input magic-tee hybrid, two non-reciprocal latching ferrite phase shifters, an out short-slot 3 db quadrature coupler, a dual driver electronic circuit, and input logic interface circuitry. The basic mode of operation of the high power ferrite microwave switch is identical to that of a four-port, differential phase shift, switchable circulator. By appropriately designing the phase shifters and electronic driver circuits to operate in the flux-transfer magnetization mode, power and temperature insensitive operation was achieved. A list of the realized characteristics of the developed units is given.

  8. Supporting technologies for a long-pulse spallation source

    SciTech Connect

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

    1998-12-31

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project is directed toward the development of the technologies required for a long-pulse, spallation neutron source (LPSS). Traditionally, spallation neutron sources have used proton accelerators that provide intense, short ({le} 1{micro}s) pulses of high-energy protons to a spallation target. A LPSS uses a proton pulse with longer time duration ({approx} 1 ms) and offers the possibility of achieving very high spallation neutron fluxes at substantially lower cost. The performance of a LPSS is very dependent on the neutronic performance of the target-moderator system. A detailed study of this performance has been carried out using Monte Carlo simulations. It should be noted that a LPSS is optimally suited to a fully coupled moderator. Neutron production per proton from such a moderator is a factor of five to seven greater than that produce d by moderators used at short pulse sources. The results of these efforts have been published in a series of articles.

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

    SciTech Connect

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

    1996-03-01

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

  10. High Power Amplifier and Power Supply

    NASA Technical Reports Server (NTRS)

    Duong, Johnny; Stride, Scot; Harvey, Wayne; Haque, Inam; Packard, Newton; Ng, Quintin; Ispirian, Julie Y.; Waian, Christopher; Janes, Drew

    2008-01-01

    A document discusses the creation of a high-voltage power supply (HVPS) that is able to contain voltages up to -20 kV, keep electrical field strengths to below 200 V/mil (approximately equal to 7.87 kV/mm), and can provide a 200-nanosecond rise/fall time focus modulator swinging between cathode potential of 16.3 kV and -19.3 kV. This HVPS can protect the 95-GHz, pulsed extended interaction klystron (EIK) from arcs/discharges from all sources, including those from within the EIK fs vacuum envelope. This innovation has a multi-winding pulse transformer design, which uses new winding techniques to provide the same delays and rise/fall times (less than 10 nanoseconds) at different potential levels ranging from -20 kV to -16 kV. Another feature involves a high-voltage printed-wiring board that was corona-free at -20 kV DC with a 3- kV AC swing. The corona-free multilayer high-voltage board is used to simulate fields of less than 200 V/mil (approximately equal to 7.87 kV/mm) at 20 kV DC. Drive techniques for the modulator FETs (field-effect transistors) (four to 10 in a series) were created to change states (3,000-V swing) without abrupt steps, while still maintaining required delays and transition times. The packing scheme includes a potting mold to house a ten-stage modulator in the space that, in the past, only housed a four-stage modulator. Problems keeping heat down were solved using aluminum oxide substrate in the high-voltage section to limit temperature rise to less than 10 while withstanding -20 kV DC voltage and remaining corona-free.

  11. Protein crystallography with spallation neutrons

    SciTech Connect

    Langan, P.; Schoenborn, Benno P.

    2003-01-01

    proteins and oriented molecular complexes. With spallation neutrons and their time dependent wavelength structure, one can select data with an optimal wavelength bandwidth and cover the whole Laue spectrum as time (wavelength) resolved diffraction data. This optimizes data quality with best peak to background ratios and provides spatial and energy resolution to eliminate peak overlaps. Such a Protein Crystallography Station (PCS) has been built and tested at Los Alamos Neutron Science Center. A partially coupled moderator is used to increase flux and data are collected by a Cylindrical He3 detector covering 120' with 200mm height. The PCS is described along with examples of data collected from a number of proteins.

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

    SciTech Connect

    Lawrence, G.P.

    1991-01-01

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

  13. Three-dimensional computational fluid dynamics for the Spallation Neutron Source liquid mercury target

    SciTech Connect

    Wendel, M.W.; Siman-Tov, M.

    1998-11-01

    The Spallation Neutron Source (SNS) is a high-power accelerator-based pulsed spallation source being designed by a multilaboratory team led by Oak Ridge National Laboratory (ORNL) to achieve high fluxes of neutrons for scientific experiments. Computational fluid dynamics (CFD) is being used to analyze the SNS design. The liquid-mercury target is subjected to the neutronic (internal) heat generation that results from the proton collisions with the mercury nuclei. The liquid mercury simultaneously serves as the neutronic target medium, transports away the heat generated within itself, and cools the metallic target structure. Recirculation and stagnation zones within the target are of particular concern because of the likelihood that they will result in local hot spots. These zones exist because the most feasible target designs include a complete U-turn flow redirection. Although the primary concern is that the target is adequately cooled, the pressure drop from inlet to outlet must also be considered because pressure drop directly affects structural loading and required pumping power. Based on the current design, a three-dimensional CFD model has been developed that includes the stainless steel target structure, the liquid-mercury target flow, and the liquid-mercury cooling jacket that wraps around the nose of the target.

  14. Integrated high power VCSEL systems

    NASA Astrophysics Data System (ADS)

    Moench, Holger; Conrads, Ralf; Gronenborn, Stephan; Gu, Xi; Miller, Michael; Pekarski, Pavel; Pollmann-Retsch, Jens; Pruijmboom, Armand; Weichmann, Ulrich

    2016-03-01

    High power VCSEL systems are a novel laser source used for thermal treatment in industrial manufacturing. These systems will be applied in many applications, which have not used a laser source before. This is enabled by the unique combination of efficiency, compactness and robustness. High power VCSEL system technology encompasses elements far beyond the VCSEL chip itself: i.e. heat sinks, bonding technology and integrated optics. This paper discusses the optimization of these components and processes specifically for building high-power laser systems with VCSEL arrays. New approaches help to eliminate components and process steps and make the system more robust and easier to manufacture. New cooler concepts with integrated electrical and mechanical interfaces have been investigated and offer advantages for high power system design. The bonding process of chips on sub-mounts and coolers has been studied extensively and for a variety of solder materials. High quality of the interfaces as well as good reliability under normal operation and thermal cycling have been realized. A viable alternative to soldering is silver sintering. The very positive results which have been achieved with a variety of technologies indicate the robustness of the VCSEL chips and their suitability for high power systems. Beam shaping micro-optics can be integrated on the VCSEL chip in a wafer scale process by replication of lenses in a polymer layer. The performance of VCSEL arrays with integrated collimation lenses has been positively evaluated and the integrated chips are fully compatible with all further assembly steps. The integrated high power systems make the application even easier and more robust. New examples in laser material processing and pumping of solid state lasers are presented.

  15. Spallation occurrence from polyamide materials irradiated by thermal plasma with water absorption

    NASA Astrophysics Data System (ADS)

    Nakano, Tomoyuki; Tanaka, Yasunori; Nakagawa, T.; Shinsei, N.; Uesugi, Y.; Ishijima, T.

    2016-09-01

    This paper first describes the effect of water absorption in polyamide material irradiated by thermal plasmas on the occurrence of spallation phenomena. The interaction between polyamide materials and arc plasmas occurs particularly in the low voltage circuit breaker and aerospace fields. Spallation phenomena are those in which polymer particles are ejected from polymer bulk materials irradiated by high heat flux. To confirm the effect of water absorption into the polyamide material on spallation phenomena, polyamide specimens with and without water absorption were irradiated by Ar inductively coupled thermal plasma. The results show that the polyamide specimen with water absorption ejected spallation particles, whereas the polyamide specimen without water absorption were only slightly ejected, indicating that water absorption promotes the occurrence of spallation. The cooling effects of the spallation polyamide 66 (PA66) particles ablation were also estimated in hot air to assess the arc quenching ability from the spallation particle inclusion. This estimation showed that 10 and more PA66 particles inclusion might decrease the air temperature by 3000 K effectively, which can be useful to enhance arc quenching in circuit breakers working in air.

  16. Pulsed high-power beams

    SciTech Connect

    Reginato, L.L.; Birx, D.L.

    1988-06-01

    The marriage of induction linac technology with nonlinear magnetic modulators has produced some unique capabilities. It is now possible to produce short-pulse electron beams with average currents measured in amperes, at gradients approaching 1-MeV/m, and with power efficiencies exceeding 50%. A 70-Mev, 3-kA induction accelerator (ETA II) constructed at the Lawrence Livermore National Laboratory incorporates the pulse technology concepts that have evolved over the past several years. The ETA II is a linear induction accelerator and provides a test facility for demonstration of the high-average-power components and high-brightness sources used in such accelerators. 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 1 kHz, and excellent reliability. 6 figs.

  17. High-Average Power Facilities

    SciTech Connect

    Dowell, David H.; Power, John G.; /Argonne

    2012-09-05

    There has been significant progress in the development of high-power facilities in recent years yet major challenges remain. The task of WG4 was to identify which facilities were capable of addressing the outstanding R&D issues presently preventing high-power operation. To this end, information from each of the facilities represented at the workshop was tabulated and the results are presented herein. A brief description of the major challenges is given, but the detailed elaboration can be found in the other three working group summaries.

  18. Spallation nucleosynthesis by accelerated charged-particles

    SciTech Connect

    Goriely, S.

    2008-05-12

    Recent observations have suggested the presence of radioactive elements, such as Pm and 84{<=}Z{<=}99 elements) at the surface of the magnetic star HD101065, also known as Przybylski's star. This star is know to be a chemically peculiar star and its anomalous 38spallation processes resulting from the interaction of the stellar material with stellar energetic particle can by themselves only explain the abundances determined by observation at the surface of HD101065. We show that specific parametric simulations can explain many different observational aspects, and in particular that a significant production of Z>30 heavy elements can be achieved. In this nucleosynthesis process, the secondary-neutron captures play a crucial role. The most attractive feature of the spallation process is the systematic production of Pm and Tc and the possible synthesis of actinides and sub-actinides.Based on such a parametric model, it is also shown that intense fluences of accelerated charged-particles interacting with surrounding material can efficiently produce elements heavier than iron. Different regimes are investigated and shown to be at the origin of p- and s-nuclei in the case of high-fluence low-flux events and r-nuclei for high-fluence high-flux irradiations. The possible existence of such irradiation events need to be confirmed by hydrodynamics simulations, but most of all by spectroscopic observations through the detection of short-lived radio-elements.

  19. High power linear accelerators for tritium production and transmutation of nuclear waste

    SciTech Connect

    Lawrence, G.P.

    1990-01-01

    Proton linacs driving high-flux spallation neutron sources are being considered for transmutation of nuclear waste and production of tritium. Advances in high-current linac technology have provided a basis for the development of credible designs for the required accelerator, which has a nominal 1.6-GeV energy, and a 250-mA cw current. A beam with these parameters incident on a liquid lead-bismuth (Pb-Bi) target can generate a thermal neutron flux of up to 5 {times} 10{sup 16} n/cm{sup 2}-s in a cylindrical blanket surrounding the spallation source. This high flux can produce tritium through the {sup 6}Li(n,{alpha})T or {sup 3}He(n,{gamma})T reactions, or can burn long-lived actinides and fission products from nuclear waste through capture and fission processes. In some system scenarios, waste actinides and/or other fissile materials in the blanket can produce sufficient fission energy to power the accelerator.

  20. Target Operational Experience at the Spallation Neutron Source

    SciTech Connect

    Riemer, Bernie; Janney, Jim G; Kaminskas, Saulius; McClintock, David A; Rosenblad, Peter M

    2013-01-01

    The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL) has operated at unprecedented power levels for a short-pulse spallation source. Target operations have been successful but not without difficulties. Three targets out of the eight used to date have ended life unexpectedly causing interruptions to the neutron science users. The first of a kind mercury target design experiences beam-pulse induced cavitation damage that is suspected in one of the target leaks. The two other targets suffered early failures due to defective welds. Diagnosing the causes of target leaks and understanding of the progression of cavitation erosion and radiation damage effects has made use of post-irradiation examination (PIE) capabilities. As a result of PIE, review of quality assurance practices and related investigations, design changes are being implemented and manufacturing oversight improved. This paper describes SNS target operating experience, including the more important observations and lessons learned.

  1. Strain rate effects for spallation of concrete

    NASA Astrophysics Data System (ADS)

    Häussler-Combe, Ulrich; Panteki, Evmorfia; Kühn, Tino

    2015-09-01

    Appropriate triaxial constitutive laws are the key for a realistic simulation of high speed dynamics of concrete. The strain rate effect is still an open issue within this context. In particular the question whether it is a material property - which can be covered by rate dependent stress strain relations - or mainly an effect of inertia is still under discussion. Experimental and theoretical investigations of spallation of concrete specimen in a Hopkinson Bar setup may bring some evidence into this question. For this purpose the paper describes the VERD model, a newly developed constitutive law for concrete based on a damage approach with included strain rate effects [1]. In contrast to other approaches the dynamic strength increase is not directly coupled to strain rate values but related to physical mechanisms like the retarded movement of water in capillary systems and delayed microcracking. The constitutive law is fully triaxial and implemented into explicit finite element codes for the investigation of a wide range of concrete structures exposed to impact and explosions. The current setup models spallation experiments with concrete specimen [2]. The results of such experiments are mainly related to the dynamic tensile strength and the crack energy of concrete which may be derived from, e.g., the velocity of spalled concrete fragments. The experimental results are compared to the VERD model and two further constitutive laws implemented in LS-Dyna. The results indicate that both viscosity and retarded damage are required for a realistic description of the material behaviour of concrete exposed to high strain effects [3].

  2. Materials Compatibility Studies for the Spallation Neutron Source

    SciTech Connect

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

    1998-09-01

    The Spallation Neutron Source (SNS) is a high power facility for producing neutrons that utilizes flowing liquid mercury inside an austenitic stainless steel container as the target for a 1.0 GeV proton beam. The energy deposited in the target is transported by two separate mercury flow streams: one to transport heat in the interior target region and one to cool the stainless steel container. Three-dimensional computational fluid dynamics simulations have been performed to predict temperature, velocity, and pressure distributions in the target. Results have generally shown that the power deposited in the bulk mercury can be effectively transported with reasonable flow rates and the bulk mercury temperature should not exceed 160{deg}C. Assuming good thermal contact, the maximum stainless steel wall temperature should be 130 {deg}C. Type 316 SS has been selected as the container material for the mercury and consequences of exposure of 316 SS to radiation, thermal shock, thermal stress, cavitation and hot, flowing mercury are all being addressed by R&D programs. In addition, corrosion studies include evaluation of Inconel 718 because it has been successfully used in previous water cooled spallation neutron systems as a window material. With type 316 SS selected to contain the mercury target of the SNS, two types of compatibility issues have been examined: LME and temperature gradient mass transfer. Studies have shown that mercury does not easily wet type 316 SS below 275{deg}C. In the LME experiments, attempts were made to promote wetting of the steel by mercury either by adding gallium to the mercury or coating the specimen with a tin-silver solder that the mercury easily wets. The latter proved more reliable in establishing wetting, but there was no evidence of LME in any of the constant extension rate tensile tests either at 23 or 100 {deg}C. Inconel 718 also showed no change in room temperature properties when tested in mercwy or mercury-gallium. However, there

  3. High voltage power transistor development

    NASA Technical Reports Server (NTRS)

    Hower, P. L.

    1981-01-01

    Design considerations, fabrication procedures, and methods of evaluation for high-voltage power-transistor development are discussed. Technique improvements such as controlling the electric field at the surface and perserving lifetimes in the collector region which have advanced the state of the art in high-voltage transistors are discussed. These improvements can be applied directly to the development of 1200 volt, 200 ampere transistors.

  4. High power, high reliability laser diodes

    NASA Astrophysics Data System (ADS)

    Scifres, D. R.; Welch, D. F.; Craig, R. R.; Zucker, E.; Major, J. S.; Harnagel, G. L.; Sakamoto, M.; Haden, J. M.; Endriz, J. G.; Kung, H.

    1992-06-01

    Results are presented on catastrophic damage limits and life-test measurements for four types of high-power laser diodes operating at wavelengths between 980 nm and 690 nm. The laser diodes under consideration are CW multimode lasers, CW laser bars, quasi-CW bars/2D stacked arrays, and single transverse mode lasers.

  5. High-power, high-efficiency FELs

    SciTech Connect

    Sessler, A.M.

    1989-04-01

    High power, high efficiency FELs require tapering, as the particles loose energy, so as to maintain resonance between the electromagnetic wave and the particles. They also require focusing of the particles (usually done with curved pole faces) and focusing of the electromagnetic wave (i.e. optical guiding). In addition, one must avoid transverse beam instabilities (primarily resistive wall) and longitudinal instabilities (i.e sidebands). 18 refs., 7 figs., 3 tabs.

  6. High temperature, high power piezoelectric composite transducers.

    PubMed

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-08-08

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  7. High Temperature, High Power Piezoelectric Composite Transducers

    PubMed Central

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  8. Computer simulations for rf design of a Spallation Neutron Source external antenna H ion source

    SciTech Connect

    Lee, Sung-Woo; Goulding, Richard Howell; Kang, Yoon W; Shin, Ki; Welton, Robert F

    2010-01-01

    Electromagnetic modeling of the multicusp external antenna H ion source for the Spallation Neutron Source SNS has been performed in order to optimize high-power performance. During development of the SNS external antenna ion source, antenna failures due to high voltage and multicusp magnet holder rf heating concerns under stressful operating conditions led to rf characteristics analysis. In rf simulations, the plasma was modeled as an equivalent lossy metal by defining conductivity as . Insulation designs along with material selections such as ferrite and Teflon could be included in the computer simulations to compare antenna gap potentials, surface power dissipations, and input impedance at the operating frequencies, 2 and 13.56 MHz. Further modeling and design improvements are outlined in the conclusion.

  9. Computer simulations for rf design of a Spallation Neutron Source external antenna H- ion source.

    PubMed

    Lee, S W; Goulding, R H; Kang, Y W; Shin, K; Welton, R F

    2010-02-01

    Electromagnetic modeling of the multicusp external antenna H(-) ion source for the Spallation Neutron Source (SNS) has been performed in order to optimize high-power performance. During development of the SNS external antenna ion source, antenna failures due to high voltage and multicusp magnet holder rf heating concerns under stressful operating conditions led to rf characteristics analysis. In rf simulations, the plasma was modeled as an equivalent lossy metal by defining conductivity as sigma. Insulation designs along with material selections such as ferrite and Teflon could be included in the computer simulations to compare antenna gap potentials, surface power dissipations, and input impedance at the operating frequencies, 2 and 13.56 MHz. Further modeling and design improvements are outlined in the conclusion.

  10. Spallation and fracture resulting from reflected and intersecting stress waves.

    NASA Technical Reports Server (NTRS)

    Kinslow, R.

    1973-01-01

    Discussion of the effects of stress waves produced in solid by explosions or high-velocity impacts. These waves rebound from free surfaces in the form of tensile waves that are capable of causing internal fractures or spallation of the material. The high-speed framing camera is shown to be an important tool for observing the stress waves and fracture in transparent targets, and its photographs provide valuable information on the mechanics of fracture.

  11. Thermal spallation drilling. Final report

    SciTech Connect

    Miska, S.; Williams, R.E.; Potter, R.M.

    1992-04-30

    Work that was performed on a previous contract with the Los Alamos National Laboratory and subsequent work at NM Tech indicated that an intermittent heating and cooling cycle, produced by heating with the conventional blast from a small jet engine and then cooled with a stream of water, would prove to be successful in spalling additional rocks. New Mexico Tech has attempted to further the use of spallation drilling to suit applications for mining and oil and gas drilling by showing that the use of a heating and cooling system would successfully penetrate otherwise unspallable rocks. This process, while showing some success in previous experimentation, has proved to work only spasmodically. The rocks tested had zones that were not spallable or were so slowly spallable that non-uniform holes were produced. Because of these irregularities, further field experimentation is not now profitable.

  12. High frequency power distribution system

    NASA Technical Reports Server (NTRS)

    Patel, Mikund R.

    1986-01-01

    The objective of this project was to provide the technology of high frequency, high power transmission lines to the 100 kW power range at 20 kHz frequency. In addition to the necessary design studies, a 150 m long, 600 V, 60 A transmission line was built, tested and delivered for full vacuum tests. The configuration analysis on five alternative configurations resulted in the final selection of the three parallel Litz straps configuration, which gave a virtually concentric design in the electromagnetic sense. Low inductance, low EMI and flexibility in handling are the key features of this configuration. The final design was made after a parametric study to minimize the losses, weight and inductance. The construction of the cable was completed with no major difficulties. The R,L,C parameters measured on the cable agreed well with the calculated values. The corona tests on insulation samples showed a safety factor of 3.

  13. High power gas laser amplifier

    DOEpatents

    Leland, Wallace T.; Stratton, Thomas F.

    1981-01-01

    A high power output CO.sub.2 gas laser amplifier having a number of sections, each comprising a plurality of annular pumping chambers spaced around the circumference of a vacuum chamber containing a cold cathode, gridded electron gun. The electron beam from the electron gun ionizes the gas lasing medium in the sections. An input laser beam is split into a plurality of annular beams, each passing through the sections comprising one pumping chamber.

  14. Target station shielding issues at the spallation neutron source.

    PubMed

    Ferguson, P D; Gallmeier, F X; Iverson, E B; Popova, I I

    2005-01-01

    Recent spallation neutron source shielding activities in support of the neutron beam shutters and the hot cell walls are presented. Existing neutron beam shutters can be replaced with concrete at low power or with concrete and steel at approximately 500 kW of beam power. Potential voids in the hot cell walls are analysed to determine the impact on dose rates as a function of void size. A change in the type of shielding work is noted as the project moved from the early design stages as a 'green field' site to the current stage as a construction project nearing completion, where issues to be addressed are approaching retrofit-type analyses.

  15. Thermal-hydraulic simulation of mercury target concepts for a pulsed spallation neutron source

    SciTech Connect

    Siman-Tov, M.; Wendel, M.; Haines, J.

    1996-06-01

    The Oak Ridge Spallation Neutron Source (ORSNS) is a high-power, accelerator-based pulsed spallation neutron source being designed by a multi-laboratory team led by Oak Ridge National Laboratory to achieve very high fluxes of neutrons for scientific experiments. The ORSNS is projected to have a 1 MW proton beam upgradable to 5 MW. About 60% of the beam power (1-5 MW, 17-83 kJ/pulse in 0.5 microsec at 60 cps) is deposited in the liquid metal (mercury) target having the dimensions of 65x30x10 cm (about 19.5 liter). Peak steady state power density is about 150 and 785 MW/m{sup 3} for 1 MW and 5 MW beam respectively, whereas peak pulsed power density is as high as 5.2 and 26.1 GW/m{sup 3}, respectively. The peak pulse temperature rise rate is 14 million C/s (for 5 MW beam) whereas the total pulse temperature rise is only 7 C. In addition to thermal shock and materials compatibility, key feasibility issues for the target are related to its thermal-hydraulic performance. This includes proper flow distribution, flow reversals, possible {open_quotes}hot spots{close_quotes} and the challenge of mitigating the effects of thermal shock through possible injection of helium bubbles throughout the mercury volume or other concepts. The general computational fluid dynamics (CFD) code CFDS-FLOW3D was used to simulate the thermal and flow distribution in three preliminary concepts of the mercury target. Very initial CFD simulation of He bubbles injection demonstrates some potential for simulating behavior of He bubbles in flowing mercury. Much study and development will be required to be able to `predict`, even in a crude way, such a complex phenomena. Future direction in both design and R&D is outlined.

  16. High-Power Rf Load

    DOEpatents

    Tantawi, Sami G.; Vlieks, Arnold E.

    1998-09-01

    A compact high-power RF load comprises a series of very low Q resonators, or chokes [16], in a circular waveguide [10]. The sequence of chokes absorb the RF power gradually in a short distance while keeping the bandwidth relatively wide. A polarizer [12] at the input end of the load is provided to convert incoming TE.sub.10 mode signals to circularly polarized TE.sub.11 mode signals. Because the load operates in the circularly polarized mode, the energy is uniformly and efficiently absorbed and the load is more compact than a rectangular load. Using these techniques, a load having a bandwidth of 500 MHz can be produced with an average power dissipation level of 1.5 kW at X-band, and a peak power dissipation of 100 MW. The load can be made from common lossy materials, such as stainless steel, and is less than 15 cm in length. These techniques can also produce loads for use as an alternative to ordinary waveguide loads in small and medium RF accelerators, in radar systems, and in other microwave applications. The design is easily scalable to other RF frequencies and adaptable to the use of other lossy materials.

  17. New head picked for European Spallation Source

    NASA Astrophysics Data System (ADS)

    Banks, Michael

    2016-06-01

    The UK physicist John Womersley is to become the next director-general of the €1.8bn European Spallation Source (ESS), which is currently being built in Lund, Sweden, by a 17-member consortium of European countries.

  18. High Power Free Electron Lasers

    SciTech Connect

    George Neil

    2004-04-12

    FEL Oscillators have been around since 1977 providing not only a test bed for the physics of Free Electron Lasers and electron/photon interactions but as a workhorse of scientific research. The characteristics that have driven the development of these sources are the desire for high peak and average power, high pulse energies, wavelength tunability, timing flexibility, and wavelengths that are unavailable from more conventional laser sources. User programs have been performed using such sources encompassing medicine, biology, solid state research, atomic and molecular physics, effects of non-linear fields, surface science, polymer science, pulsed laser vapor deposition, to name just a few. Recently the incorporation of energy recovery systems has permitted extension of the average power capabilities to the kW level and beyond. Development of substantially higher power systems with applications in defense and security is believed feasible with modest R&D efforts applied to a few technology areas. This paper will discuss at a summary level the physics of such devices, survey existing and planned facilities, and touch on the applications that have driven the development of these popular light sources.

  19. High average power solid state laser power conditioning system

    SciTech Connect

    Steinkraus, R.F.

    1987-03-03

    The power conditioning system for the High Average Power Laser program at Lawrence Livermore National Laboratory (LLNL) is described. The system has been operational for two years. It is high voltage, high power, fault protected, and solid state. The power conditioning system drives flashlamps that pump solid state lasers. Flashlamps are driven by silicon control rectifier (SCR) switched, resonant charged, (LC) discharge pulse forming networks (PFNs). The system uses fiber optics for control and diagnostics. Energy and thermal diagnostics are monitored by computers.

  20. High voltage DC power supply

    DOEpatents

    Droege, T.F.

    1989-12-19

    A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively. 7 figs.

  1. High voltage DC power supply

    DOEpatents

    Droege, Thomas F.

    1989-01-01

    A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively.

  2. High power cladding light strippers

    NASA Astrophysics Data System (ADS)

    Wetter, Alexandre; Faucher, Mathieu; Sévigny, Benoit

    2008-02-01

    The ability to strip cladding light from double clad fiber (DCF) fibers is required for many different reasons, one example is to strip unwanted cladding light in fiber lasers and amplifiers. When removing residual pump light for example, this light is characterized by a large numerical aperture distribution and can reach power levels into the hundreds of watts. By locally changing the numerical aperture (N.A.) of the light to be stripped, it is possible to achieve significant attenuation even for the low N.A. rays such as escaped core modes in the same device. In order to test the power-handling capability of this device, one hundred watts of pump and signal light is launched from a tapered fusedbundle (TFB) 6+1x1 combiner into a high power-cladding stripper. In this case, the fiber used in the cladding stripper and the output fiber of the TFB was a 20/400 0.06/0.46 N.A. double clad fiber. Attenuation of over 20dB in the cladding was measured without signal loss. By spreading out the heat load generated by the unwanted light that is stripped, the package remained safely below the maximum operating temperature internally and externally. This is achieved by uniformly stripping the energy along the length of the fiber within the stripper. Different adhesive and heat sinking techniques are used to achieve this uniform removal of the light. This suggests that these cladding strippers can be used to strip hundreds of watts of light in high power fiber lasers and amplifiers.

  3. High power, high beam quality regenerative amplifier

    DOEpatents

    Hackel, Lloyd A.; Dane, Clifford B.

    1993-01-01

    A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

  4. High power, high beam quality regenerative amplifier

    DOEpatents

    Hackel, L.A.; Dane, C.B.

    1993-08-24

    A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

  5. Cryogenic System for the Spallation Neutron Source

    NASA Astrophysics Data System (ADS)

    Arenius, D.; Chronis, W.; Creel, J.; Dixon, K.; Ganni, V.; Knudsen, P.

    2004-06-01

    The Spallation Neutron Source (SNS) is a neutron-scattering facility being built at Oak Ridge, TN for the US Department of Energy. The SNS accelerator linac consists of superconducting radio-frequency (SRF) cavities in cryostats (cryomodules). The linac cryomodules are cooled to 2.1 K by a 2300 watt cryogenic refrigeration system. As an SNS partner laboratory, Jefferson Lab is responsible for the installed integrated cryogenic system design for the SNS linac accelerator consisting of major subsystem equipment engineered and procured from industry. Jefferson Lab's work included developing the major vendor subsystem equipment procurement specifications, equipment procurement, and the integrated system engineering support of the field installation and commissioning. The major cryogenic system components include liquid nitrogen storage, gaseous helium storage, cryogen distribution transfer line system, 2.1-K cold box consisting of four stages of cold compressors, 4.5-K cold box, warm helium compressors with its associated oil removal, gas management, helium purification, gas impurity monitoring systems, and the supportive utilities of electrical power, cooling water and instrument air. The system overview, project organization, the important aspects, and the capabilities of the cryogenic system are described.

  6. Improved Programmable High-Voltage Power Supply

    NASA Technical Reports Server (NTRS)

    Castell, Karen; Rutberg, Arthur

    1994-01-01

    Improved dc-to-dc converter functions as programmable high-voltage power supply with low-power-dissipation voltage regulator on high-voltage side. Design of power supply overcomes deficiencies of older designs. Voltage regulation with low power dissipation provided on high-voltage side.

  7. High Power Helicon Propulsion Experiments

    NASA Astrophysics Data System (ADS)

    Ziemba, Timothy; Slough, John; Winglee, Robert

    2005-02-01

    The High Power Helicon (HPH) under development at the University of Washington may have an attractive application as an electrode-less in-space thruster. Output plasma characteristics show that plasma is created in and near the helicon coil and is accelerated by a helicon induced axial potential downstream away from the HPH. The bulk acceleration of the plasma is believed to be due to a coupling of the plasma electrons to the helicon field, which in turn transfers energy to the ions via an ambipolar electric field. Downstream electric potentials of greater than 150 volts having been measured with the amplitude of the electric field being dependent on experimentally controlled parameters. Time of flight measurements of the plasma transiting downstream show specific impulses (Isp) near 2000 seconds for Argon with calculated thrust levels near 1 Newton for input powers to the plasma in the tens of kilowatts. The system is capable of using different neutral gases as propellants with nitrogen and hydrogen having baseline Isp levels of 3000 and 5000 seconds respectfully giving some variability in Isp and thrust by the choice of propellants. Current work focuses on the determination and optimization of the system efficiencies and increasing output power levels.

  8. High-power pulsed lasers

    SciTech Connect

    Holzrichter, J.F.

    1980-04-02

    The ideas that led to the successful construction and operation of large multibeam fusion lasers at the Lawrence Livermore Laboratory are reviewed. These lasers are based on the use of Nd:glass laser materials. However, most of the concepts are applicable to any laser being designed for fusion experimentation. This report is a summary of lectures given by the author at the 20th Scottish University Summer School in Physics, on Laser Plasma Interaction. This report includes basic concepts of the laser plasma system, a discussion of lasers that are useful for short-pulse, high-power operation, laser design constraints, optical diagnostics, and system organization.

  9. RF Distribution System for High Power Test of the SNS Cryomodule

    SciTech Connect

    Lee, Sung-Woo; Kang, Yoon W; Broyles, Michael R; Crofford, Mark T; Geng, Xiaosong; Kim, Sang-Ho; Phibbs, Curtis L; Strong, William Herb; Peglow, Robert C; Vassioutchenko, Alexandre V

    2012-01-01

    A four-way waveguide RF power distribution system for testing the Spallation Neutron Source (SNS) multi-cavity cryomodule to investigate the collective behavior has been developed. A single klystron operating at 805MHz for 1.3 msec at 60Hz powers the 4-way waveguide splitter to deliver up to 400 kW to individual cavities. Each cavity is fed through a combination of waveguide splitters and vector modulators (VM) to provide independent magnitude and phase controls. The waveguide vector modulator consists of two quadrature hybrids and two motorized waveguide phase shifters. The phase shifters and the assembled waveguide vector modulators were individually tested and characterized for low power and high RF power in the SNS RF test facility. Precise calibrations of magnitude and phase were performed to generate the look up tables (LUTs) to provide operational references during the cryomodule test. An I-Q demodulator module was developed and utilized to measure relative phases in pulsed high RF power operation. PLC units were developed for mechanical control of the phase shifters. Initial low/high power measurements were made using LabVIEW. An operation algorithm has been implemented into EPICS control for the cryomodule test stand.

  10. High frequency, high power capacitor development

    NASA Astrophysics Data System (ADS)

    White, C. W.; Hoffman, P. S.

    1983-03-01

    A program to develop a special high energy density, high power transfer capacitor to operate at frequency of 40 kHz, 600 V rms at 125 A rms plus 600 V dc bias for space operation. The program included material evaluation and selection, a capacitor design was prepared, a thermal analysis performed on the design. Fifty capacitors were manufactured for testing at 10 kHz and 40 kHz for 50 hours at Industrial Electric Heating Co. of Columbus, Ohio. The vacuum endurance test used on environmental chamber and temperature plate furnished by Maxwell. The capacitors were energized with a special power conditioning apparatus developed by Industrial Electric Heating Co. Temperature conditions of the capacitors were monitored by IEHCo test equipment. Successful completion of the vacuum endurance test series confirmed achievement of the main goal of producing a capacitor or reliable operation at high frequency in an environment normally not hospitable to electrical and electronic components. The capacitor developed compared to a typical commercial capacitor at the 40 kHz level represents a decrease in size and weight by a factor of seven.

  11. High frequency, high power capacitor development

    NASA Technical Reports Server (NTRS)

    White, C. W.; Hoffman, P. S.

    1983-01-01

    A program to develop a special high energy density, high power transfer capacitor to operate at frequency of 40 kHz, 600 V rms at 125 A rms plus 600 V dc bias for space operation. The program included material evaluation and selection, a capacitor design was prepared, a thermal analysis performed on the design. Fifty capacitors were manufactured for testing at 10 kHz and 40 kHz for 50 hours at Industrial Electric Heating Co. of Columbus, Ohio. The vacuum endurance test used on environmental chamber and temperature plate furnished by Maxwell. The capacitors were energized with a special power conditioning apparatus developed by Industrial Electric Heating Co. Temperature conditions of the capacitors were monitored by IEHCo test equipment. Successful completion of the vacuum endurance test series confirmed achievement of the main goal of producing a capacitor or reliable operation at high frequency in an environment normally not hospitable to electrical and electronic components. The capacitor developed compared to a typical commercial capacitor at the 40 kHz level represents a decrease in size and weight by a factor of seven.

  12. High Power, High Voltage Electric Power System for Electric Propulsion

    NASA Technical Reports Server (NTRS)

    Aintablian, Harry; Kirkham, Harold; Timmerman, Paul

    2006-01-01

    This paper provides an overview of the 30 KW, 600 V MRHE power subsystem. Descriptions of the power subsystem elements, the mode of power transfer, and power and mass estimates are presented. A direct-drive architecture for electric propulsion is considered which reduces mass and complexity. Solar arrays with concentrators are used for increased efficiency. Finally, the challenges due to the environment of a hypothetical lunar mission as well as due to the advanced technologies considered are outlined.

  13. Energy deposition calculated by PHITS code in Pb spallation target

    NASA Astrophysics Data System (ADS)

    Yu, Quanzhi

    2016-01-01

    Energy deposition in a Pb spallation target irradiated by high energetic protons was calculated by PHITS2.52 code. The validation of the energy deposition and neutron production calculated by PHITS code was performed. Results show good agreements between the simulation results and the experimental data. Detailed comparison shows that for the total energy deposition, PHITS simulation result was about 15% overestimation than that of the experimental data. For the energy deposition along the length of the Pb target, the discrepancy mainly presented at the front part of the Pb target. Calculation indicates that most of the energy deposition comes from the ionizations of the primary protons and the produced secondary particles. With the event generator mode of PHITS, the deposit energy distribution for the particles and the light nulclei is presented for the first time. It indicates that the primary protons with energy more than 100 MeV are the most contributors to the total energy deposition. The energy depositions peaking at 10 MeV and 0.1 MeV, are mainly caused by the electrons, pions, d, t, 3He and also α particles during the cascade process and the evaporation process, respectively. The energy deposition density caused by different proton beam profiles are also calculated and compared. Such calculation and analyses are much helpful for better understanding the physical mechanism of energy deposition in the spallation target, and greatly useful for the thermal hydraulic design of the spallation target.

  14. Department of Energy review of the National Spallation Neutron Source Project

    SciTech Connect

    1997-06-01

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

  15. A very intense neutrino super beam experiment for leptonic CP violation discovery based on the European spallation source linac

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    Very intense neutrino beams and large neutrino detectors will be needed in order to enable the discovery of CP violation in the leptonic sector. We propose to use the proton linac of the European Spallation Source currently under construction in Lund, Sweden, to deliver, in parallel with the spallation neutron production, a very intense, cost effective and high performance neutrino beam. The baseline program for the European Spallation Source linac is that it will be fully operational at 5 MW average power by 2022, producing 2 GeV 2.86 ms long proton pulses at a rate of 14 Hz. Our proposal is to upgrade the linac to 10 MW average power and 28 Hz, producing 14 pulses/s for neutron production and 14 pulses/s for neutrino production. Furthermore, because of the high current required in the pulsed neutrino horn, the length of the pulses used for neutrino production needs to be compressed to a few μs with the aid of an accumulator ring. A long baseline experiment using this Super Beam and a megaton underground Water Cherenkov detector located in existing mines 300-600 km from Lund will make it possible to discover leptonic CP violation at 5 σ significance level in up to 50% of the leptonic Dirac CP-violating phase range. This experiment could also determine the neutrino mass hierarchy at a significance level of more than 3 σ if this issue will not already have been settled by other experiments by then. The mass hierarchy performance could be increased by combining the neutrino beam results with those obtained from atmospheric neutrinos detected by the same large volume detector. This detector will also be used to measure the proton lifetime, detect cosmological neutrinos and neutrinos from supernova explosions. Results on the sensitivity to leptonic CP violation and the neutrino mass hierarchy are presented.

  16. H- radio frequency source development at the Spallation Neutron Sourcea)

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

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

    SciTech Connect

    Welton, Robert F; Pennisi, Terry R; Roseberry, Ron T; Stockli, Martin P

    2012-01-01

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

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

    PubMed

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

    2012-02-01

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

  19. Application of high power lasers to space power and propulsion

    NASA Technical Reports Server (NTRS)

    Nored, D. L.

    1976-01-01

    The transmission of laser power over long distances for applications such as direct conversion to propulsive thrust or electrical power is considered. Factors discussed include: problems inherent in transmitting, propagating, and receiving the laser beam over long ranges; high efficiency, closed-cycle, continuous wave operation; advancement of CO2 laser technology; and compatibility with photovoltaic power conversion devices.

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

    SciTech Connect

    Gianluigi Ciovati

    2001-09-01

    The Spallation Neutron Source project includes a superconducting linac section in the energy range from 186 MeV to 1000 MeV. For this energy range two types of cavities are needed with geometrical {beta} values of {beta} = 0.61 and {beta} = 0.81. An aggressive cavity prototyping program is being pursued at Jefferson Lab, which calls for fabricating and testing four {beta} = 0.61 cavities and two {beta} = 0.81 cavities. Both types consist of six cells made from high purity niobium and feature one HOM coupler on each beam pipe and a port for a high power coaxial input coupler. Three of the four {beta} = 0.61 cavities will be used for a cryomodule test in early 2002. At this time four medium beta cavities and one high beta cavity have been completed at JLab. The first tests on the {beta} = 0.61 and {beta} = 0.81 exceeded the design values for gradient and Q value: E{sub acc} = 10.1 MV/m and Q = 5 x 10{sup 9} at 2.1K for the {beta} = 0.61 and E{sub acc} = 12.3 MV/m and Q = 5 x 10{sup 9} at 2.1 K for the {beta} = 0.81. One of the medium beta cavities has been equipped with an integrated helium vessel and measurements of the static Lorentz force detuning have been done and compared to the ''bare'' cavities. In addition two single cell cavities have been fabricated, equipped with welded-on HOM couplers. They are being used to evaluate the HOM couplers with respect to multipacting, fundamental mode rejection and HOM damping as far as possible in a single cell. This paper describes the cavity design with respect to electromagnetic and mechanical features, the fabrication efforts and the results obtained with the different cavities existing at the time of this workshop.

  1. High Power Orbit Transfer Vehicle

    DTIC Science & Technology

    2003-07-01

    PowerSail’s design . The power subsystem includes the solar array design and cell selection, load, and batteries to store the power captured by the...the complete mission. The mass of the solar array guides the design of the propulsion system and batteries needed on PowerSail. For example, the...to the size of the batteries . For this reason, minimizing the mass of the solar array is designated a weight of 2/20. Minimizing the total mass is

  2. R&D-needs and opportunities to broaden the data base on materials and technology for liquid metal spallation targets

    SciTech Connect

    Bauer, G.S.

    1996-06-01

    Liquid metals have so far only been used to a very limited extent as spallation targets, notably at the ISOLDE-facility at CERN (Pb and La) to produce radioactive isotopes. Virtually no systematic studies have been carried out so far. The available data base is by no means sufficient to answer conclusively very important questions such as predicting reliably the service time of medium-to-high power target systems or determining precisely what technological measures are required and appropriate to maintain an optimum coolant quality, to mitigate the effects of pressure waves in short pulse sources and others. During the workshop several areas have been identified, where there exists an urgent need for improved knowledge and reliable data, and opportunities have been presented to acquire such knowledge and to generate such data. Opportunities to do such research and pertinent know-how, although scarce, are spread over institutions in several countries, and efforts to use these opportunities often require substantial resources both in man power and money. The workshop participants therefore unanimously supported the view that a coordinated and internationally concerted effort should be undertaken to make the best possible use of existing opportunities and available resources in order to develop the knowledge and technology necessary for the deployment and safe operation of target systems suitable for pulsed spallation neutron sources in the multi-megawatt range of beam power.

  3. High power laser apparatus and system

    NASA Technical Reports Server (NTRS)

    Evans, J. C., Jr.; Brandhorst, H. W., Jr. (Inventor)

    1975-01-01

    A high-power, continuous-wave laser was designed for use in power transmission and energy-collecting systems, and for producing incoherent light for pumping a laser material. The laser has a high repetitive pulsing rate per unit time, resulting in a high-power density beam. The laser is composed of xenon flash tubes powered by fast-charging capacitors flashed in succession by a high-speed motor connected to an automobile-type distributor.

  4. Optics assembly for high power laser tools

    DOEpatents

    Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.

    2016-06-07

    There is provided a high power laser rotational optical assembly for use with, or in high power laser tools for performing high power laser operations. In particular, the optical assembly finds applications in performing high power laser operations on, and in, remote and difficult to access locations. The optical assembly has rotational seals and bearing configurations to avoid contamination of the laser beam path and optics.

  5. European Spallation Source and Neutron Science

    NASA Astrophysics Data System (ADS)

    Yeck, James

    2014-03-01

    International collaborations in large-scale scientific projects can link Sciences and Society. Following this goal, the European Spallation Source (ESS) is a multi-disciplinary research centre under design and construction in Lund, Sweden. This new facility is funded by a collaboration of 17 European countries. Scandinavia is providing 50 percent of the construction cost whilst the other member states are providing financial support mainly via in-kind contribution from institutes, laboratories or industries of the given countries. Scientists and engineers from 35 different countries are members of the workforce in Lund who participate in its design and construction. The ESS will enable new opportunities for researchers in fields of life sciences, energy, environmental technology, cultural heritage and fundamental physics by producing very high flux neutrons to study condensed matter physics, chemistry, biology, nuclear physics and materials science. The ESS will be up to 30 times brighter than today's leading facilities and neutron sources. A tungsten target and a 5 MW long pulse proton accelerator, composed mainly of superconducting Radio-Frequency components, are used to achieve these goals.

  6. Spallation of the Galileo probe heat shield

    NASA Astrophysics Data System (ADS)

    Lundell, J. H.

    1982-06-01

    The Galileo probe heat shield will encounter severe radiative and convective heating during entry into Jupiter's atmosphere. The shield is made of two different carbon phenolic composites; one is chopped-molded, and the other is tape-wrapped, both of which tend to spall under intense heating conditions. To characterize this phenomenon, an experimental program, using a gasdynamic laser, was initiated. Tests were performed at a variety of radiation intensities, and both the total and spallation mass-loss rates were measured and correlated with intensity. These correlations were then applied to calculated flight heating conditions for two model atmospheres. Entry of a 310-kg probe into the nominal atmosphere would result in a spallation mass loss of 6.3 kg, or 7.4% of the expected thermochemical mass loss. Similarly, entry of that probe into the cool-dense atmosphere would result in 11.9 kg of spallation, or about 10% of the expected thermochemical mass loss.

  7. ULTRA HIGH POWER TRANSMISSION LINE TECHNIQUES

    DTIC Science & Technology

    The ultra-high power transmission line techniques including both failure mechanisms and component design are discussed. Failures resulting from...a waveguide. In view of the many advantages of the low loss mode in circular waveguide for ultra-high power levels, a mode transducer and a two...percent of the peak power of a standard rectangular wave guide. Water cooling is provided for high average power operation. Analysis of mode sup pression

  8. Simplified High-Power Inverter

    NASA Technical Reports Server (NTRS)

    Edwards, D. B.; Rippel, W. E.

    1984-01-01

    Solid-state inverter simplified by use of single gate-turnoff device (GTO) to commutate multiple silicon controlled rectifiers (SCR's). By eliminating conventional commutation circuitry, GTO reduces cost, size and weight. GTO commutation applicable to inverters of greater than 1-kilowatt capacity. Applications include emergency power, load leveling, drives for traction and stationary polyphase motors, and photovoltaic-power conditioning.

  9. 5 MW pulsed spallation neutron source, Preconceptual design study

    SciTech Connect

    Not Available

    1994-06-01

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

  10. VESPA: The vibrational spectrometer for the European Spallation Source.

    PubMed

    Fedrigo, Anna; Colognesi, Daniele; Bertelsen, Mads; Hartl, Monika; Lefmann, Kim; Deen, Pascale P; Strobl, Markus; Grazzi, Francesco; Zoppi, Marco

    2016-06-01

    VESPA, Vibrational Excitation Spectrometer with Pyrolytic-graphite Analysers, aims to probe molecular excitations via inelastic neutron scattering. It is a thermal high resolution inverted geometry time-of-flight instrument designed to maximise the use of the long pulse of the European Spallation Source. The wavelength frame multiplication technique was applied to provide simultaneously a broad dynamic range (about 0-500 meV) while a system of optical blind choppers allows to trade flux for energy resolution. Thanks to its high flux, VESPA will allow the investigation of dynamical and in situ experiments in physical chemistry. Here we describe the design parameters and the corresponding McStas simulations.

  11. VESPA: The vibrational spectrometer for the European Spallation Source

    NASA Astrophysics Data System (ADS)

    Fedrigo, Anna; Colognesi, Daniele; Bertelsen, Mads; Hartl, Monika; Lefmann, Kim; Deen, Pascale P.; Strobl, Markus; Grazzi, Francesco; Zoppi, Marco

    2016-06-01

    VESPA, Vibrational Excitation Spectrometer with Pyrolytic-graphite Analysers, aims to probe molecular excitations via inelastic neutron scattering. It is a thermal high resolution inverted geometry time-of-flight instrument designed to maximise the use of the long pulse of the European Spallation Source. The wavelength frame multiplication technique was applied to provide simultaneously a broad dynamic range (about 0-500 meV) while a system of optical blind choppers allows to trade flux for energy resolution. Thanks to its high flux, VESPA will allow the investigation of dynamical and in situ experiments in physical chemistry. Here we describe the design parameters and the corresponding McStas simulations.

  12. Rotary high power transfer apparatus

    NASA Technical Reports Server (NTRS)

    Jacobson, Peter E. (Inventor); Porter, Ryan S. (Inventor)

    1987-01-01

    An apparatus for reducing terminal-to-terminal circuit resistance and enhancing heat transfer in a rotary power transfer apparatus of the roll ring type comprising a connecting thimble for attaching an external power cable to a cone shaped terminal which is attached to a tab integral to an outer ring. An inner ring having a spherical recess mates with the spherical end of a tie connector. A cone shaped terminal is fitted to a second connecting thimble for attaching a second external power cable.

  13. High power RF solid state power amplifier system

    NASA Technical Reports Server (NTRS)

    Sims, III, William Herbert (Inventor); Chavers, Donald Gregory (Inventor); Richeson, James J. (Inventor)

    2011-01-01

    A high power, high frequency, solid state power amplifier system includes a plurality of input multiple port splitters for receiving a high-frequency input and for dividing the input into a plurality of outputs and a plurality of solid state amplifier units. Each amplifier unit includes a plurality of amplifiers, and each amplifier is individually connected to one of the outputs of multiport splitters and produces a corresponding amplified output. A plurality of multiport combiners combine the amplified outputs of the amplifiers of each of the amplifier units to a combined output. Automatic level control protection circuitry protects the amplifiers and maintains a substantial constant amplifier power output.

  14. High voltage-high power components for large space power distribution systems

    NASA Technical Reports Server (NTRS)

    Renz, D. D.

    1984-01-01

    Space power components including a family of bipolar power switching transistors, fast switching power diodes, heat pipe cooled high frequency transformers and inductors, high frequency conduction cooled transformers, high power-high frequency capacitors, remote power controllers and rotary power transfer devices were developed. Many of these components such as the power switching transistors, power diodes and the high frequency capacitor are commercially available. All the other components were developed to the prototype level. The dc/dc series resonant converters were built to the 25 kW level.

  15. Computer simulations for rf design of a Spallation Neutron Source external antenna H{sup -} ion source

    SciTech Connect

    Lee, S. W.; Kang, Y. W.; Shin, K.; Welton, R. F.; Goulding, R. H.

    2010-02-15

    Electromagnetic modeling of the multicusp external antenna H{sup -} ion source for the Spallation Neutron Source (SNS) has been performed in order to optimize high-power performance. During development of the SNS external antenna ion source, antenna failures due to high voltage and multicusp magnet holder rf heating concerns under stressful operating conditions led to rf characteristics analysis. In rf simulations, the plasma was modeled as an equivalent lossy metal by defining conductivity as {sigma}. Insulation designs along with material selections such as ferrite and Teflon could be included in the computer simulations to compare antenna gap potentials, surface power dissipations, and input impedance at the operating frequencies, 2 and 13.56 MHz. Further modeling and design improvements are outlined in the conclusion.

  16. Optical model methods of predicting nuclide production from spallation reactions.

    PubMed

    Ramsey, C R; Townsend, L W; Tripathi, R K; Cucinotta, F A

    1998-02-01

    Quantum mechanical optical model methods for calculating isotope production cross sections from the spallation of heavy nuclei by high-energy protons are developed from a modified abrasion-ablation collision formalism. The abrasion step is treated quantum-mechanically as a knockout process which leaves the residual prefragment nucleus in an excited state. In ablation the prefragment deexcites to produce the final fragment. The excitation energies of the prefragments are estimated from a combination of liquid drop and frictional-spectator interaction considerations. Estimates of elemental and isotopic production cross sections are in good agreement with recently published cross section measurements.

  17. High Power Electromagnetic (HPEM) Threat Analysis

    DTIC Science & Technology

    2008-04-01

    EMERGING THREATS ...... 13 HEMP coupling characteristics ............................................................................... 13 High power...microwave (HPEM) coupling characteristics ..................................... 16 High power microwave: local protective measures...ncy (W1 Figure 22. Various bands summarizing EM threats. HEMP coupling characteristics In the early 1960’s, researchers proposed a theory that a high

  18. High average power induction accelerators

    SciTech Connect

    Swingle, J.C.

    1985-10-01

    The induction accelerator is discussed with respect to general background and concept, beam transport, scaling, pulse power technology, and the electron beam injector. A discussion of the factors which affect the scaling of the intensity of the beam is given. Limiting factors include collective forces in the beam, virtual cathode formation, surroundings, and beam breakup instability. 24 refs., 11 figs. (WRF)

  19. Moisture-Induced TBC Spallation on Turbine Blade Samples

    NASA Technical Reports Server (NTRS)

    Smialek, James

    2011-01-01

    Delayed failure of TBCs is a widely observed laboratory phenomenon, although many of the early observations went unreported. The weekend effect or DeskTop Spallation (DTS) is characterized by initial survival of a TBC after accelerated laboratory thermal cycling, then failure by exposure to ambient humidity or water. Once initiated, failure can occur quite dramatically in less than a second. To this end, the water drop test and digital video recordings have become useful techniques in studies at NASA (Smialek, Zhu, Cuy), DECHMA (Rudolphi, Renusch, Schuetze), and CNRS Toulouse/SNECMA (Deneux, Cadoret, Hervier, Monceau). In the present study the results for a commercial turbine blade, with a standard EB-PVD 7YSZ TBC top coat and Pt-aluminide diffusion bond coat are reported. Cut sections were intermittently oxidized at 1100, 1150, and 1200 C and monitored by weight change and visual appearance. Failures were distributed widely over a 5-100 hr time range, depending on temperature. At some opportune times, failure was captured by video recording, documenting the appearance and speed of the moisture-induced spallation process. Failure interfaces exhibited alumina scale grains, decorated with Ta-rich oxide particles, and alumina inclusions as islands and streamers. The phenomenon is thus rooted in moisture-induced delayed spallation (MIDS) of the alumina scale formed on the bond coat. In that regard, many studies show the susceptibility of alumina scales to moisture, as long as high strain energy and a partially exposed interface exist. The latter conditions result from severe cyclic oxidation conditions, which produce a highly stressed and partially damaged scale. In one model, it has been proposed that moisture reacts with aluminum in the bond coat to release hydrogen atoms that embrittle the interface. A negative synergistic effect with interfacial sulfur is also invoked.

  20. Moisture-Induced TBC Spallation on Turbine Blade Samples

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2011-01-01

    Delayed failure of TBCs is a widely observed laboratory phenomenon, although many of the early observations went unreported. "The weekend effect" or "DeskTop Spallation" (DTS) is characterized by initial survival of a TBC after accelerated laboratory thermal cycling, then failure by exposure to ambient humidity or water. Once initiated, failure can occur quite dramatically in less than a second. To this end, the water drop test and digital video recordings have become useful techniques in studies at NASA (Smialek, Zhu, Cuy), DECHMA (Rudolphi, Renusch, Schuetze), and CNRS Toulouse/SNECMA (Deneux, Cadoret, Hervier, Monceau). In the present study the results for a commercial turbine blade, with a standard EB-PVD 7YSZ TBC top coat and Pt-aluminide diffusion bond monitored by weight change and visual appearance. Failures were distributed widely over a 5-100 hr time range, depending on temperature. At some opportune times, failure was captured by video recording, documenting the appearance and speed of the moisture-induced spallation process. Failure interfaces exhibited alumina scale grains, decorated with Ta-rich oxide particles, and alumina inclusions as islands and streamers. The phenomenon is thus rooted in moisture-induced delayed spallation (MIDS) of the alumina scale formed on the bond coat. In that regard, many studies show the susceptibility of alumina scales to moisture, as long as high strain energy and a partially exposed interface exist. The latter conditions result from severe cyclic oxidation conditions, which produce a highly stressed and partially damaged scale. In one model, it has been proposed that moisture reacts with aluminum in the bond coat to release hydrogen atoms that 'embrittle' the interface. A negative synergistic effect with interfacial sulfur is also invoked.

  1. Operation of high power converters in parallel

    NASA Technical Reports Server (NTRS)

    Decker, D. K.; Inouye, L. Y.

    1993-01-01

    High power converters that are used in space power subsystems are limited in power handling capability due to component and thermal limitations. For applications, such as Space Station Freedom, where multi-kilowatts of power must be delivered to user loads, parallel operation of converters becomes an attractive option when considering overall power subsystem topologies. TRW developed three different unequal power sharing approaches for parallel operation of converters. These approaches, known as droop, master-slave, and proportional adjustment, are discussed and test results are presented.

  2. An explosively driven high-power microwave pulsed power system

    NASA Astrophysics Data System (ADS)

    Elsayed, M. A.; Neuber, A. A.; Dickens, J. C.; Walter, J. W.; Kristiansen, M.; Altgilbers, L. L.

    2012-02-01

    The increased popularity of high power microwave systems and the various sources to drive them is the motivation behind the work to be presented. A stand-alone, self-contained explosively driven high power microwave pulsed power system has been designed, built, and tested at Texas Tech University's Center for Pulsed Power and Power Electronics. The system integrates four different sub-units that are composed of a battery driven prime power source utilizing capacitive energy storage, a dual stage helical flux compression generator as the main energy amplification device, an integrated power conditioning system with inductive energy storage including a fast opening electro-explosive switch, and a triode reflex geometry virtual cathode oscillator as the microwave radiating source. This system has displayed a measured electrical source power level of over 5 GW and peak radiated microwaves of about 200 MW. It is contained within a 15 cm diameter housing and measures 2 m in length, giving a housing volume of slightly less than 39 l. The system and its sub-components have been extensively studied, both as integrated and individual units, to further expand on components behavior and operation physics. This report will serve as a detailed design overview of each of the four subcomponents and provide detailed analysis of the overall system performance and benchmarks.

  3. A High Power Frequency Doubled Fiber Laser

    NASA Technical Reports Server (NTRS)

    Thompson, Robert J.; Tu, Meirong; Aveline, Dave; Lundblad, Nathan; Maleki, Lute

    2003-01-01

    This viewgraph presentation reports on the development of a high power 780 nm laser suitable for space applications of laser cooling. A possible solution is to use frequency doubling of high power 1560 nm telecom lasers. The presentation shows a diagram of the frequency conversion, and a graph of the second harmonic generation in one crystal, and the use of the cascading crystals. Graphs show the second harmonic power as a function of distance between crystals, second harmonic power vs. pump power, tunability of laser systems.

  4. The Spallation Neutron Source Beam Commissioning and Initial Operations

    SciTech Connect

    Henderson, Stuart; Aleksandrov, Alexander V.; Allen, Christopher K.; Assadi, Saeed; Bartoski, Dirk; Blokland, Willem; Casagrande, F.; Campisi, I.; Chu, C.; Cousineau, Sarah M.; Crofford, Mark T.; Danilov, Viatcheslav; Deibele, Craig E.; Dodson, George W.; Feshenko, A.; Galambos, John D.; Han, Baoxi; Hardek, T.; Holmes, Jeffrey A.; Holtkamp, N.; Howell, Matthew P.; Jeon, D.; Kang, Yoon W.; Kasemir, Kay; Kim, Sang-Ho; Kravchuk, L.; Long, Cary D.; McManamy, T.; Pelaia, II, Tom; Piller, Chip; Plum, Michael A.; Pogge, James R.; Purcell, John David; Shea, T.; Shishlo, Andrei P; Sibley, C.; Stockli, Martin P.; Stout, D.; Tanke, E.; Welton, Robert F; Zhang, Y.; Zhukov, Alexander P

    2015-09-01

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

  5. High Density Power Converters for Photovoltaic Power Management

    NASA Astrophysics Data System (ADS)

    Sangwan, Rahul

    In typical photovoltaic systems, PV cells are connected in series to achieve high output voltages, which decreases conduction losses and helps the downstream power electronics operate at higher efficiencies. A series connection means that the current through the string is limited by the worst case cell, substring, or module, which can result in suboptimal operation of the rest of the string. Given how even small shading can have a large effect on performance, there has been growing interest in the use of distributed power management architectures to mitigate losses from variation in PV systems. In particular, partial power processing converters have gained traction as a means to improve the performance of PV arrays with small, distributed converters that configure in parallel with PV cells. These converters can use low voltage components, only process a fraction of the total power allowing them to achieve higher efficiencies and power density and also have higher reliability. This work details the design and operation of a partial power processing converter implemented as a Resonant Switched Capacitor (ReSC) converter. An integrated circuit (IC) is designed in 0.18 mum CMOS process. Operation at high frequencies (20-50 MHz) allows high levels of integration with air core inductors directly attached to the die through a gold bump, solder reflow process. Test results for the IC are presented with power density and efficiency metrics. The IC is then used as a partial power processing converter to implement equalization with a specially constructed PV panel. The converter is shown to mitigate power loss due to mismatch.

  6. Test facilities for high power electric propulsion

    NASA Technical Reports Server (NTRS)

    Sovey, James S.; Vetrone, Robert H.; Grisnik, Stanley P.; Myers, Roger M.; Parkes, James E.

    1991-01-01

    Electric propulsion has applications for orbit raising, maneuvering of large space systems, and interplanetary missions. These missions involve propulsion power levels from tenths to tens of megawatts, depending upon the application. General facility requirements for testing high power electric propulsion at the component and thrust systems level are defined. The characteristics and pumping capabilities of many large vacuum chambers in the United States are reviewed and compared with the requirements for high power electric propulsion testing.

  7. High Power Josephson Effect Sources

    DTIC Science & Technology

    1994-09-01

    large spacing was nsed ,along with cooling water, os Iao a d$ to ensure the substrate temperature did not rise durn theCox flow Osiltr.adsaljnto ry~ h m...Here two arra’s. a 400 s.m Josephson effect detector and an SIS mixer are "I integrated on a single silicon substrate . One array func- tions as the...junction’s shunt resistor, on array’s output power and detector’s current- voltage characteristics are also discussed. I. INTRODUCTION - U Phb &z locked

  8. Control system for the Spallation Neutron Source H{sup -} source test facility Allison scanner

    SciTech Connect

    Long, C. D.; Stockli, M. P.; Gorlov, T. V.; Han, B.; Murray, S. N.; Pennisi, T. R.

    2010-02-15

    Spallation Neutron Source is currently in progress of a multiyear plan to ramp ion beam power to the initial design power of 1.4 MW. Key to reaching this goal is understanding and improving the operation of the H{sup -} ion source. An Allison scanner was installed on the ion source in the test facility to support this improvement. This paper will discuss the hardware and the software control system of the installed Allison scanner. The hardware for the system consists of several parts. The heart of the system is the scanner head, complete with associated bias plates, slits, and signal detector. There are two analog controlled high voltage power supplies to bias the plates in the head, and a motor with associated controller to position the head in the beam. A multifunction data acquisition card reads the signals from the signal detector, as well as supplies the analog voltage control for the power supplies. To synchronize data acquisition with the source, the same timing signal that is used to trigger the source itself is used to trigger data acquisition. Finally, there is an industrial personal computer to control the rest of the hardware. Control software was developed using National Instruments LABVIEW, and consists of two parts: a data acquisition program to control the hardware and a stand alone application for offline user data analysis.

  9. High power laser perforating tools and systems

    SciTech Connect

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2014-04-22

    ystems devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser perforation of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to perforate such boreholes.

  10. Very High Power THz Radiation Sources.

    PubMed

    Carr, G L; Martin, M C; McKinney, W R; Jordan, K; Neil, G R; Williams, G P

    2003-06-01

    We report the production of high power (20watts average, ∼ 1 Megawatt peak) broadbandTHz light based on coherent emission fromrelativistic electrons. Such sources areideal for imaging, for high power damagestudies and for studies of non-linearphenomena in this spectral range. Wedescribe the source, presenting theoreticalcalculations and their experimentalverification. For clarity we compare thissource with one based on ultrafast lasertechniques.

  11. Photoconductive switching for high power microwave generation

    SciTech Connect

    Pocha, M.D.; Hofer, W.W.

    1990-10-01

    Photoconductive switching is a technology that is being increasingly applied to generation of high power microwaves. Two primary semiconductors used for these devices are silicon and gallium arsenide. Diamond is a promising future candidate material. This paper discusses the important material parameters and switching modes, critical issues for microwave generation, and future directions for this high power, photoconductive switching technology.

  12. High efficiency solar photovoltaic power module concept

    NASA Technical Reports Server (NTRS)

    Bekey, I.

    1978-01-01

    The investigation of a preliminary concept for high efficiency solar power generation in space is presented. The concept was a synergistic combination of spectral splitting, tailored bandgap cells, high concentration ratios, and cool cell areas.

  13. High temperature power electronics for space

    NASA Technical Reports Server (NTRS)

    Hammoud, Ahmad N.; Baumann, Eric D.; Myers, Ira T.; Overton, Eric

    1991-01-01

    A high temperature electronics program at NASA Lewis Research Center focuses on dielectric and insulating materials research, development and testing of high temperature power components, and integration of the developed components and devices into a demonstrable 200 C power system, such as inverter. An overview of the program and a description of the in-house high temperature facilities along with experimental data obtained on high temperature materials are presented.

  14. High Power Klystrons for Efficient Reliable High Power Amplifiers.

    DTIC Science & Technology

    1980-11-01

    components of the space charge waves in the electron beam of a microwave tube are combined to produce more highly concentrated electron bunches raising the...the drift lengths to enhance the 2nd harmonic component in the space charge waves . The latter method was utilized in the VKC-7790. Computer...photographs, operating/ maintanance instructions, layout drawings/schematics and the purchase specification are included, in the above order, in

  15. High power plasma spraying of oxide ceramics

    SciTech Connect

    Lugscheider, E.; Jungklaus, H.; Schwier, G.; Mathesius, H.; Heinrich, P.

    1995-12-31

    New developed high power plasma spray (HPPS) systems offer opportunities for generating both high thermal as well as high kinetic energy transfer to the powder particles. The operation level can be elevated up to 250 kW for continuous processing. PLCs and mass flow controls support high power processing under production conditions. The process is designed for applying large quantities even of high melt materials, such as oxide ceramics. High power plasma processing may result in enhanced coating characteristics. The work in this paper shows first conclusions for processing commercial powders such as alumina, alumina-titania, chromia and a recently developed multicomponent oxide with a HPPS system. Particle velocities were measured after optimizing spraying parameters. Coatings were evaluated by optical microscopy (microstructure and porosity), microhardness and pin-on-disc abrasive wear tests. Powder types and sizes as well as the systems configuration are considered for a general discussion of the capability and limitation in high power plasma spraying.

  16. Initial tests of the Spallation Neutron Source H{sup -} ion source with an external antenna

    SciTech Connect

    Welton, R.F.; Stockli, M.P.; Murray, S.N.; Kang, Y.; Peters, J.

    2006-03-15

    The ion source for the Spallation Neutron Source (SNS) is a radio-frequency (rf) multicusp source designed to deliver H{sup -} beam pulses of 40 mA to the SNS accelerator with a normalized root-mean-square emittance of less than 0.2{pi} mm mrad, with a pulse length of 1 ms and a repetition rate of 60 Hz. In order to achieve this performance the source must operate with both high-pulse rf power, {approx}50 kW, and high average rf power, {approx}3.5 kW, over a continuous operational period of 3 weeks. During operation at these power levels the plasma-immersed, porcelain-coated rf antenna is susceptible to damage, limiting source lifetime. We are therefore developing an ion source where the plasma is separated from the Cu antenna by an Al{sub 2}O{sub 3} discharge chamber. This article describes the ion source, presents initial beam extraction measurements, and details our ongoing effort to develop this concept into a suitable ion source for the SNS.

  17. COHERENT at the Spallation Neutron Source

    NASA Astrophysics Data System (ADS)

    Scholberg, Kate; Coherent Collaboration

    2016-03-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, Tennessee, provides an intense isotropic flux of neutrinos in the few tens-of-MeV range, with a sharply-pulsed timing structure which is beneficial for background rejection. This talk will describe aspects of COHERENT, the experimental program underway to measure CEvNS (Coherent Elastic Neutrino-Nucleus Scattering) using low-energy nuclear recoil detectors.

  18. High power diode lasers reliability experiment

    NASA Astrophysics Data System (ADS)

    Lu, Guoguang; Xie, Shaofeng; Hao, Mingming; Huang, Yun; En, Yunfei

    2013-12-01

    In order to evaluate and obtain the actual lifetime data of high power laser diodes, an automated high power laser diodes reliability experiment was developed and reported in this paper. This computer controlled setup operates the laser diodes 24 hours a day, the parameters such as output power, wavelength were test once in one hour. The experiment has 60 work stations, the temperature control range is from 25°C to 70°C, and the output power of the aging device is beyond 20W.

  19. High-Temperature Passive Power Electronics

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In many future NASA missions - such as deep-space exploration, the National AeroSpace Plane, minisatellites, integrated engine electronics, and ion or arcjet thrusters - high-power electrical components and systems must operate reliably and efficiently in high-temperature environments. The high-temperature power electronics program at the NASA Lewis Research Center focuses on dielectric and insulating material research, the development and characterization of high-temperature components, and the integration of the developed components into a demonstrable 200 C power system - such as an inverter. NASA Lewis has developed high-temperature power components through collaborative efforts with the Air Force Wright Laboratory, Northrop Grumman, and the University of Wisconsin. Ceramic and film capacitors, molypermalloy powder inductors, and a coaxially wound transformer were designed, developed, and evaluated for high-temperature operation.

  20. Impact spallation processes on the Moon: A case study from the size and shape analysis of ejecta boulders and secondary craters of Censorinus crater

    NASA Astrophysics Data System (ADS)

    Krishna, N.; Kumar, P. Senthil

    2016-01-01

    Impact spallation is a fundamental process responsible for formation of ejecta boulders from impact craters. Although theoretical spallation models were developed about three decades ago, only limited geological observations have been made so far to test these models. The 3.8 km Censorinus crater on the Moon provides an excellent opportunity for studying the impact spallation processes associated with a fresh simple crater formed by oblique impact. Using the Lunar Reconnaissance Orbiter Narrow Angle Camera images, we prepared the ejecta boulder distribution map of Censorinus crater and measured the boulder sizes and shapes. Mapping of about 242,000 ejecta boulders enabled us to document the size distribution of boulders both radial and concentric to the impact crater. Larger size boulders dominate the crater rim areas, while they become smaller away from the crater. The boulder distribution exhibits a radial asymmetry suggesting Censorinus is a oblique impact, in which the uprange ejecta have smaller ranges with larger concentration of boulders near the southwestern crater rim, while the downrange ejecta are in general characterized by smaller boulders with high spatial dispersion. The cumulative size-frequency distribution (CSFD) of boulders shows a highly variable fragmentation history in which the uprange boulders suffered more complex fragmentation. The ejecta boulders also exhibit a variety of shapes that are gleaned from their axial ratios and edge angle characteristics. There is a general decrease of axial ratios away from the crater rim. Rectangular boulders dominate the crater rim and they become more equant away from the crater. In addition to the boulder sizes, the boulder shape distribution also exhibits a mild asymmetry in response to the oblique impact. Small size fresh impact craters (84,000 craters) are abundant on the Censorinus ejecta and post-date Censorinus. These craters are found in two morphologic types in which a large majority of craters

  1. High power solid state switches

    NASA Astrophysics Data System (ADS)

    Gundersen, Martin

    1991-11-01

    We have successfully produced an optically triggered thyristor based in Gallium Arsenide, developed a model for breakdown, and are developing two related devices, including a Gallium Arsenide based static inductor thyristor. We are getting at the basic limitations of Gallium Arsenide for these applications, and are developing models for the physical processes that will determine device limitations. The previously supported gas phase work - resulting in the back-lighted thyratron (BLT) - has actually resulted in a very changed view of how switching can be accomplished, and this is impacting the design of important machines. The BLT is being studied internationally: in Japan for laser fusion and laser isotope separation. ITT has built a BLT that has switched 30 kA at 60 kV in testing at NSWC Dahlgren and the device is being commercialized by another American company. Versions of the switch are now being tested for excimer laser and other applications. Basically, the switch, which arose from pulse power physics studies at USC, can switch more current faster (higher di/dt), with less housekeeping, and with other advantageous properties. There are a large number of other new applications, include kinetic energy weapons, pulsed microwave sources and R.F. accelerators.

  2. Spallation target cryogenic cooling design challenges at the European Spallation Source

    NASA Astrophysics Data System (ADS)

    Jurns, J.; Ringnér, J.; Quack, H.; Arnold, P.; Weisend, J. G., II; Lyngh, D.

    2015-12-01

    The European Spallation Source (ESS) project is a neutron spallation source research facility currently being designed and built outside of Lund, Sweden. A linear accelerator delivers a 5 MW, 2.0 GeV, 62.5 mA proton beam to a spallation target to generate fast neutrons. Supercritical hydrogen circulates through two moderators surrounding the target, and transforms the fast neutrons emitted into slow neutrons, which are the final form of useful radiation. The supercritical hydrogen is in turn cooled from a helium cryogenic plant operating at 15-20 K. The supercritical cryogenic hydrogen circuit is a dynamic system, subject to significant changes in heat load. Proper pressure control of this system is critical to assure safe operation. The interaction between the hydrogen system and helium cryoplant poses unique challenges. This paper investigates the impact of the hydrogen system constraints on operation and control of the helium cryoplant, and suggests design options for the helium circuit.

  3. High power ultrashort pulse lasers

    SciTech Connect

    Perry, M.D.

    1994-10-07

    Small scale terawatt and soon even petawatt (1000 terawatt) class laser systems are made possible by application of the chirped-pulse amplification technique to solid-state lasers combined with the availability of broad bandwidth materials. These lasers make possible a new class of high gradient accelerators based on the large electric fields associated with intense laser-plasma interactions or from the intense laser field directly. Here, we concentrate on the laser technology to produce these intense pulses. Application of the smallest of these systems to the production of high brightness electron sources is also introduced.

  4. HIGH AVERAGE POWER OPTICAL FEL AMPLIFIERS.

    SciTech Connect

    BEN-ZVI, ILAN, DAYRAN, D.; LITVINENKO, V.

    2005-08-21

    Historically, the first demonstration of the optical FEL was in an amplifier configuration at Stanford University [l]. There were other notable instances of amplifying a seed laser, such as the LLNL PALADIN amplifier [2] and the BNL ATF High-Gain Harmonic Generation FEL [3]. However, for the most part FELs are operated as oscillators or self amplified spontaneous emission devices. Yet, in wavelength regimes where a conventional laser seed can be used, the FEL can be used as an amplifier. One promising application is for very high average power generation, for instance FEL's with average power of 100 kW or more. The high electron beam power, high brightness and high efficiency that can be achieved with photoinjectors and superconducting Energy Recovery Linacs (ERL) combine well with the high-gain FEL amplifier to produce unprecedented average power FELs. This combination has a number of advantages. In particular, we show that for a given FEL power, an FEL amplifier can introduce lower energy spread in the beam as compared to a traditional oscillator. This properly gives the ERL based FEL amplifier a great wall-plug to optical power efficiency advantage. The optics for an amplifier is simple and compact. In addition to the general features of the high average power FEL amplifier, we will look at a 100 kW class FEL amplifier is being designed to operate on the 0.5 ampere Energy Recovery Linac which is under construction at Brookhaven National Laboratory's Collider-Accelerator Department.

  5. High-power picosecond laser pulse recirculation.

    PubMed

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P J

    2010-07-01

    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high-power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering-based light sources. We demonstrate up to 40x average power enhancement of frequency-doubled submillijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

  6. High Power Picosecond Laser Pulse Recirculation

    SciTech Connect

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P

    2010-04-12

    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering based light sources. We demonstrate up to 36x average power enhancement of frequency doubled sub-millijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

  7. High-efficiency solid state power amplifier

    NASA Technical Reports Server (NTRS)

    Wallis, Robert E. (Inventor); Cheng, Sheng (Inventor)

    2005-01-01

    A high-efficiency solid state power amplifier (SSPA) for specific use in a spacecraft is provided. The SSPA has a mass of less than 850 g and includes two different X-band power amplifier sections, i.e., a lumped power amplifier with a single 11-W output and a distributed power amplifier with eight 2.75-W outputs. These two amplifier sections provide output power that is scalable from 11 to 15 watts without major design changes. Five different hybrid microcircuits, including high-efficiency Heterostructure Field Effect Transistor (HFET) amplifiers and Monolithic Microwave Integrated Circuit (MMIC) phase shifters have been developed for use within the SSPA. A highly efficient packaging approach enables the integration of a large number of hybrid circuits into the SSPA.

  8. High Power Co-Axial Coupler

    SciTech Connect

    Neubauer, M.; Dudas, A.; Rimmer, Robert A.; Guo, Jiquan; Williams, R. Scott

    2013-12-01

    A very high power Coax RF Coupler (MW-Level) is very desirable for a number of accelerator and commercial applications. For example, the development of such a coupler operating at 1.5 GHz may permit the construction of a higher-luminosity version of the Electron-Ion Collider (EIC) being planned at JLab. Muons, Inc. is currently funded by a DOE STTR grant to develop a 1.5-GHz high-power doublewindowcoax coupler with JLab (about 150 kW). Excellent progress has been made on this R&D project, so we propose an extension of this development to build a very high power coax coupler (MW level peak power and a max duty factor of about 4%). The dimensions of the current coax coupler will be scaled up to provide higher power capability.

  9. THE SPALLATION NEUTRON SOURCE CRYOMODULE TEST STAND RF SYSTEM

    SciTech Connect

    Crofford, Mark T; Ball, Jeffrey Allen; Davidson Jr, Taylor L; Hardek, Thomas W; Heidenreich, Dale A; Kasemir, Kay; Kim, Sang-Ho; Kang, Yoon

    2008-01-01

    The Spallation Neutron Source (SNS) has recently commissioned a cryomodule test facility for the repair and testing of the super-conducting radio-frequency (SRF) cavities. This facility utilizes the original 402.5/805 MHz Radio Frequency (RF) Klystron Test Stand as its power source along with dual Low Level RF (LLRF) control systems. One control system is based on the standard SNS Linac LLRF controls with a second system for open-loop only control. The system is designed to allow simultaneous testing of devices in the test cave and other devices which can be tested outside of the enclosure. Initial tests have shown good results; some improvements are yet to be implemented.

  10. 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

  11. Electron Cloud Mitigation in the Spallation Neutron Source Ring

    SciTech Connect

    Wei, J.; Blaskiewicz, Michael; Brodowski, J.; Cameron, P.; Davino, Daniele; Fedotov, A.; He, P.; Hseuh, H.; Lee, Y.Y.; Ludewig, H.; Meng, W.; Raparia, D.; Tuozzolo, J.; Zhang, S.Y.; Catalan-Lasheras, N.; Macek, R.J.; Furman, Miguel A.; Aleksandrov, A.; Cousineau, S.; Danilov, V.; Henderson, S.; /Brookhaven /CERN /LANL, Ctr. for Nonlinear Studies /LBL, Berkeley /Oak Ridge /SLAC

    2008-03-17

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

  12. Electron-cloud mitigation in the spallation neutron source ring

    SciTech Connect

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

    2003-05-01

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

  13. High voltage photovoltaic power converter

    DOEpatents

    Haigh, Ronald E.; Wojtczuk, Steve; Jacobson, Gerard F.; Hagans, Karla G.

    2001-01-01

    An array of independently connected photovoltaic cells on a semi-insulating substrate contains reflective coatings between the cells to enhance efficiency. A uniform, flat top laser beam profile is illuminated upon the array to produce electrical current having high voltage. An essentially wireless system includes a laser energy source being fed through optic fiber and cast upon the photovoltaic cell array to prevent stray electrical signals prior to use of the current from the array. Direct bandgap, single crystal semiconductor materials, such as GaAs, are commonly used in the array. Useful applications of the system include locations where high voltages are provided to confined spaces such as in explosive detonation, accelerators, photo cathodes and medical appliances.

  14. Materials considerations for the National Spallation Neutron Source target

    SciTech Connect

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

    1997-08-01

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

  15. Ceramics for High Power Lasers

    DTIC Science & Technology

    2011-12-01

    stoichiometry, determined by either atomistic simulation or XRD. The simulation results correspond to various defect reactions identified in this work...spatially resolved. The data obtained with this set-up have been calibrated against high-quality fused silica and sapphire absorption standards having...Coefficient (ppm/cm) YAG, Z-713 750 Nd:YAG, Z-714 1050 Gd:YAG, Z-715 1100 Single-crystal Sc1 1000 Kono1 135 Fused silica standard 10 Sapphire

  16. High-power red VCSEL arrays

    NASA Astrophysics Data System (ADS)

    Seurin, Jean-Francois; Khalfin, Viktor; Xu, Guoyang; Miglo, Alexander; Li, Daizong; Zhou, Delai; Sundaresh, Mukta; Zou, Wei-Xiong; Lu, Chien-Yao; Wynn, James D.; Ghosh, Chuni

    2013-03-01

    High-power red laser sources are used in many applications such as cosmetics, cancer photodynamic therapy, and DNA sequencing in the medical field, laser-based RGB projection display, and bar-code scanning to name a few. Verticalcavity surface-emitting lasers (VCSELs) can be used as high-power laser sources, as efficient single devices can be configured into high-power two-dimensional arrays and scaled into modules of arrays. VCSELs emit in a circular, uniform beam which can greatly reduce the complexity and cost of optics. Other advantages include a narrow and stable emission spectrum, low speckle of the far-field emission, and good reliability. However, developing efficient red VCSEL sources presents some challenges because of the reduced quantum-well carrier confinement and the increased Aluminum content (to avoid absorption) which increases thermal impedance, and also decreases the DBR index contrast resulting in increased penetration length and cavity losses. We have recently developed VCSEL devices lasing in the visible 6xx nm wavelength band, and reaching 30% power conversion efficiency. We fabricated high-power 2D arrays by removing the GaAs substrate entirely and soldered the chips on high thermal conductivity submounts. Such arrays have demonstrated several Watts of output power at room temperature, in continuous-wave (CW) operation. Several tens of Watts are obtained in QCW operation. Results and challenges of these high-power visible VCSEL arrays will be discussed.

  17. High Power Amplifier Harmonic Output Level Measurement

    NASA Technical Reports Server (NTRS)

    Perez, R. M.; Hoppe, D. J.; Khan, A. R.

    1995-01-01

    A method is presented for the measurement of the harmonic output power of high power klystron amplifiers, involving coherent hemispherical radiation pattern measurements of the radiated klystron output. Results are discussed for the operation in saturated and unsaturated conditions, and with a waveguide harmonic filter included.

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

    SciTech Connect

    Greene, G.L.

    1995-12-31

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

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

    PubMed

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

    2011-02-14

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

  20. Optical power splitter for splitting high power light

    DOEpatents

    English, R.E. Jr.; Christensen, J.J.

    1995-04-18

    An optical power splitter for the distribution of high-power light energy has a plurality of prisms arranged about a central axis to form a central channel. The input faces of the prisms are in a common plane which is substantially perpendicular to the central axis. A beam of light which is substantially coaxial to the central axis is incident on the prisms and at least partially strikes a surface area of each prism input face. The incident beam also partially passes through the central channel. 5 figs.

  1. Optical power splitter for splitting high power light

    DOEpatents

    English, Jr., Ronald E.; Christensen, John J.

    1995-01-01

    An optical power splitter for the distribution of high-power light energy has a plurality of prisms arranged about a central axis to form a central channel. The input faces of the prisms are in a common plane which is substantially perpendicular to the central axis. A beam of light which is substantially coaxial to the central axis is incident on the prisms and at least partially strikes a surface area of each prism input face. The incident beam also partially passes through the central channel.

  2. High power density carbonate fuel cell

    SciTech Connect

    Yuh, C.; Johnsen, R.; Doyon, J.; Allen, J.

    1996-12-31

    Carbonate fuel cell is a highly efficient and environmentally clean source of power generation. Many organizations worldwide are actively pursuing the development of the technology. Field demonstration of multi-MW size power plant has been initiated in 1996, a step toward commercialization before the turn of the century, Energy Research Corporation (ERC) is planning to introduce a 2.85MW commercial fuel cell power plant with an efficiency of 58%, which is quite attractive for distributed power generation. However, to further expand competitive edge over alternative systems and to achieve wider market penetration, ERC is exploring advanced carbonate fuel cells having significantly higher power densities. A more compact power plant would also stimulate interest in new markets such as ships and submarines where space limitations exist. The activities focused on reducing cell polarization and internal resistance as well as on advanced thin cell components.

  3. Coupling output of multichannel high power microwaves

    SciTech Connect

    Li Guolin; Shu Ting; Yuan Chengwei; Zhang Jun; Yang Jianhua; Jin Zhenxing; Yin Yi; Wu Dapeng; Zhu Jun; Ren Heming; Yang Jie

    2010-12-15

    The coupling output of multichannel high power microwaves is a promising technique for the development of high power microwave technologies, as it can enhance the output capacities of presently studied devices. According to the investigations on the spatial filtering method and waveguide filtering method, the hybrid filtering method is proposed for the coupling output of multichannel high power microwaves. As an example, a specific structure is designed for the coupling output of S/X/X band three-channel high power microwaves and investigated with the hybrid filtering method. In the experiments, a pulse of 4 GW X band beat waves and a pulse of 1.8 GW S band microwave are obtained.

  4. High power millimeter wave source development program

    NASA Technical Reports Server (NTRS)

    George, T. V.

    1989-01-01

    High power millimeter wave sources for fusion program; ECH source development program strategy; and 1 MW, 140 GHz gyrotron experiment design philosophy are briefly outlined. This presentation is represented by viewgraphs only.

  5. High Voltage Power Transmission for Wind Energy

    NASA Astrophysics Data System (ADS)

    Kim, Young il

    The high wind speeds and wide available area at sea have recently increased the interests on offshore wind farms in the U.S.A. As offshore wind farms become larger and are placed further from the shore, the power transmission to the onshore grid becomes a key feature. Power transmission of the offshore wind farm, in which good wind conditions and a larger installation area than an onshore site are available, requires the use of submarine cable systems. Therefore, an underground power cable system requires unique design and installation challenges not found in the overhead power cable environment. This paper presents analysis about the benefit and drawbacks of three different transmission solutions: HVAC, LCC/VSC HVDC in the grid connecting offshore wind farms and also analyzed the electrical characteristics of underground cables. In particular, loss of HV (High Voltage) subsea power of the transmission cables was evaluated by the Brakelmann's theory, taking into account the distributions of current and temperature.

  6. High power regenerative laser amplifier

    DOEpatents

    Miller, J.L.; Hackel, L.A.; Dane, C.B.; Zapata, L.E.

    1994-02-08

    A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse. 7 figures.

  7. High power regenerative laser amplifier

    DOEpatents

    Miller, John L.; Hackel, Lloyd A.; Dane, Clifford B.; Zapata, Luis E.

    1994-01-01

    A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse.

  8. Very high power THz radiation sources

    SciTech Connect

    Carr, G.L.; Martin, Michael C.; McKinney, Wayne R.; Jordan, K.; Neil, George R.; Williams, G.P.

    2002-10-31

    We report the production of high power (20 watts average, {approx} 1 Megawatt peak) broadband THz light based on coherent emission from relativistic electrons. Such sources are ideal for imaging, for high power damage studies and for studies of non-linear phenomena in this spectral range. We describe the source, presenting theoretical calculations and their experimental verification. For clarity we compare this source to one based on ultrafast laser techniques.

  9. Very High Power THz Radiation Sources

    SciTech Connect

    G.L. Carr; Michael C. Martin; Wayne R. McKinney; Kevin Jordan; George R. Neil; Gwyn P. Williams

    2002-10-01

    We report the production of high power (20 watts average, {approx}1 Megawatt peak) broadband THz light based on coherent emission from relativistic electrons. Such sources are ideal for imaging, for high power damage studies and for studies of non-linear phenomena in this spectral range. We describe the source, presenting theoretical calculations and their experimental verification. For clarity, we compare this sources with one based on ultrafast laser techniques.

  10. Spacecraft high-voltage power supply construction

    NASA Technical Reports Server (NTRS)

    Sutton, J. F.; Stern, J. E.

    1975-01-01

    The design techniques, circuit components, fabrication techniques, and past experience used in successful high-voltage power supplies for spacecraft flight systems are described. A discussion of the basic physics of electrical discharges in gases is included and a design rationale for the prevention of electrical discharges is provided. Also included are typical examples of proven spacecraft high-voltage power supplies with typical specifications for design, fabrication, and testing.

  11. High Power Short Wavelength Laser Development

    DTIC Science & Technology

    1977-11-01

    Unlimited güä^äsjäsiiiüüü X NRTC-77-43R P I High Power Short Wavelength Laser Development November 1977 D. B. Cohn and W. B. Lacina...NO NRTC-77-43R, «. TITLE fana »uetjjitj BEFORE COMPLETING FORM CIPIENT’S CATALOO NUMBER KIGH.POWER SHORT WAVELENGTH LASER DEVELOPMENT , 7...fWhtn Data Enterte NRTC-77-43R HIGH POWER SHORT WAVELENGTH LASER DEVELOPMENT ARPA Order Number: Program Code Number: Contract Number: Principal

  12. Inverter design for high frequency power distribution

    NASA Technical Reports Server (NTRS)

    King, R. J.

    1985-01-01

    A class of simple resonantly commutated inverters are investigated for use in a high power (100 KW - 1000 KW) high frequency (10 KHz - 20 KHz) AC power distribution system. The Mapham inverter is found to provide a unique combination of large thyristor turn-off angle and good utilization factor, much better than an alternate 'current-fed' inverter. The effects of loading the Mapham inverter entirely with rectifier loads are investigated by simulation and with an experimental 3 KW 20 KHz inverter. This inverter is found to be well suited to a power system with heavy rectifier loading.

  13. High-Speed, high-power, switching transistor

    NASA Technical Reports Server (NTRS)

    Carnahan, D.; Ohu, C. K.; Hower, P. L.

    1979-01-01

    Silicon transistor rate for 200 angstroms at 400 to 600 volts combines switching speed of transistors with ruggedness, power capacity of thyristor. Transistor introduces unique combination of increased power-handling capability, unusally low saturation and switching losses, and submicrosecond switching speeds. Potential applications include high power switching regulators, linear amplifiers, chopper controls for high frequency electrical vehicle drives, VLF transmitters, RF induction heaters, kitchen cooking ranges, and electronic scalpels for medical surgery.

  14. Dissertation: Precompound Emission of Energetic Light Fragments in Spallation Reactions

    SciTech Connect

    Kerby, Leslie Marie

    2015-08-04

    Emission of light fragments (LF) from nuclear reactions is an open question. Different reaction mechanisms contribute to their production; the relative roles of each, and how they change with incident energy, mass number of the target, and the type and emission energy of the fragments is not completely understood. None of the available models are able to accurately predict emission of LF from arbitrary reactions. However, the ability to describe production of LF (especially at energies ≳ 30 MeV) from many reactions is important for different applications, such as cosmic-ray-induced Single Event Upsets (SEUs), radiation protection, and cancer therapy with proton and heavy-ion beams, to name just a few. The Cascade-Exciton Model (CEM) version 03.03 and the Los Alamos version of the Quark-Gluon String Model (LAQGSM) version 03.03 event generators in Monte Carlo N-Particle Transport Code version 6 (MCNP6) describe quite well the spectra of fragments with sizes up to ⁴He across a broad range of target masses and incident energies (up to ~ 5 GeV for CEM and up to ~ 1 TeV/A for LAQGSM). However, they do not predict the high energy tails of LF spectra heavier than ⁴He well. Most LF with energies above several tens of MeV are emitted during the precompound stage of a reaction. The current versions of the CEM and LAQGSM event generators do not account for precompound emission of LF larger than ⁴He. The aim of our work is to extend the precompound model in them to include such processes, leading to an increase of predictive power of LF-production in MCNP6. This entails upgrading the Modified Exciton Model currently used at the preequilibrium stage in CEM and LAQGSM. It also includes expansion and examination of the coalescence and Fermi break-up models used in the precompound stages of spallation reactions within CEM and LAQGSM. Extending our models to include emission of fragments heavier than ⁴He at the precompound stage has indeed provided results that have much

  15. Thermal-hydraulic analysis of the liquid mercury target for the national spallation neutron source

    SciTech Connect

    Siman-Tov, M.; Wendel, M.W.; Haines, J.R.; Rogers, M.

    1997-04-01

    The National Spallation Neutron Source (NSNS) is a high-energy, accelerator-based spallation neutron source being designed by a multi-laboratory team led by Oak Ridge National Laboratory (ORNL) to achieve very high fluxes of neutrons for scientific experiments. The NSNS is proposed to have a 1 MW beam of high-energy ({approximately}1 GeV) protons upgradable to 5 MW and operating at 60 Hz with a pulse duration of 0.5 {mu}s. Peak steady-state power density in the target is about 640 MW/m{sup 3} for 1 MW, whereas the pulse instantaneous peak power density is as high as 22,000 GW/m{sup 3}. The local peak temperature rise for a single pulse over it`s time-averaged value is only 6{degrees}C, but the rate of this temperature rise during the pulse is extremely fast ({approximately}12 million {degrees}C/s). In addition to the resulting thermal shock and materials compatibility concerns, key feasibility issues for the target are related to its thermal-hydraulic performance. These include proper flow distribution, flow reversals and stagnation zones, possible {open_quotes}hot spots{close_quotes}, cooling of the beam {open_quotes}window{close_quotes}, and the challenge of mitigating the effects of thermal shock through possible injection of helium bubbles. An analytic approach was used on the PC spreadsheet EXCEL to evaluate target design options and to determine the global T/H parameters in the current concept. The general computational fluid dynamics (CFD) code CFX was used to simulate the detailed time-averaged two-dimensional thermal and flow distributions in the liquid mercury. In this paper, an overview of the project and the results of this preliminary work are presented. Heat transfer characteristics of liquid mercury under wetting and non-wetting conditions are discussed, and future directions of the program in T/H analysis and R&D are outlined.

  16. The NASA CSTI high capacity power project

    NASA Technical Reports Server (NTRS)

    Winter, J.; Dudenhoefer, J.; Juhasz, A.; Schwarze, G.; Patterson, R.; Ferguson, D.; Titran, R.; Schmitz, P.; Vandersande, J.

    1992-01-01

    The SP-100 Space Nuclear Power Program was established in 1983 by DOD, DOE, and NASA as a joint program to develop technology for military and civil applications. Starting in 1986, NASA has funded a technology program to maintain the momentum of promising aerospace technology advancement started during Phase 1 of SP-100 and to strengthen, in key areas, the chances for successful development and growth capability of space nuclear reactor power systems for a wide range of future space applications. The elements of the Civilian Space Technology Initiative (CSTI) High Capacity Power Project include Systems Analysis, Stirling Power Conversion, Thermoelectric Power Conversion, Thermal Management, Power Management, Systems Diagnostics, Environmental Interactions, and Material/Structural Development. Technology advancement in all elements is required to provide the growth capability, high reliability and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall project will develop and demonstrate the technology base required to provide a wide range of modular power systems compatible with the SP-100 reactor which facilitates operation during lunar and planetary day/night cycles as well as allowing spacecraft operation at any attitude or distance from the sun. Significant accomplishments in all of the project elements will be presented, along with revised goals and project timelines recently developed.

  17. The NASA CSTI High Capacity Power Project

    SciTech Connect

    Winter, J.; Dudenhoefer, J.; Juhasz, A.; Schwarze, G.; Patterson, R.; Ferguson, D.; Titran, R.; Schmitz, P.; Vandersande, J.

    1994-09-01

    The SP-100 Space Nuclear Power Program was established in 1983 by DOD, DOE, and NASA as a joint program to develop technology for military and civil applications. Starting in 1986, NASA has funded a technology program to maintain the momentum of promising aerospace technology advancement started during Phase I of SP-100 and to strengthen, in key areas, the changes for successful development and growth capability of space nuclear reactor power systems for a wide range of future space applications. The elements of the CSTI High Capacity Power Project include Systems Analysis, Stirling Power Conversion, Thermoelectric Power Conversion, Thermal Management, Power Management, Systems Diagnostics, Environmental Interactions, and Material/Structural Development. Technology advancement in all elements is required to provide the growth capability, high reliability and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall project with develop and demonstrate the technology base required to provide a wide range of modular power systems compatible with the SP-100 reactor which facilitates operation during lunar and planetary day/night cycles as well as allowing spacecraft operation at any attitude or distance from the sun. Significant accomplishments in all of the project elements will be presented, along with revised goals and project timelines recently developed.

  18. Core Vessel Insert Handling Robot for the Spallation Neutron Source

    SciTech Connect

    Graves, Van B; Dayton, Michael J

    2011-01-01

    The Spallation Neutron Source provides the world's most intense pulsed neutron beams for scientific research and industrial development. Its eighteen neutron beam lines will eventually support up to twenty-four simultaneous experiments. Each beam line consists of various optical components which guide the neutrons to a particular instrument. The optical components nearest the neutron moderators are the core vessel inserts. Located approximately 9 m below the high bay floor, these inserts are bolted to the core vessel chamber and are part of the vacuum boundary. They are in a highly radioactive environment and must periodically be replaced. During initial SNS construction, four of the beam lines received Core Vessel Insert plugs rather than functional inserts. Remote replacement of the first Core Vessel Insert plug was recently completed using several pieces of custom-designed tooling, including a highly complicated Core Vessel Insert Robot. The design of this tool are discussed.

  19. Advances in high power semiconductor diode lasers

    NASA Astrophysics Data System (ADS)

    Ma, Xiaoyu; Zhong, Li

    2008-03-01

    High power semiconductor lasers have broad applications in the fields of military and industry. Recent advances in high power semiconductor lasers are reviewed mainly in two aspects: improvements of diode lasers performance and optimization of packaging architectures of diode laser bars. Factors which determine the performance of diode lasers, such as power conversion efficiency, temperature of operation, reliability, wavelength stabilization etc., result from a combination of new semiconductor materials, new diode structures, careful material processing of bars. The latest progress of today's high-power diode lasers at home and abroad is briefly discussed and typical data are presented. The packaging process is of decisive importance for the applicability of high-power diode laser bars, not only technically but also economically. The packaging techniques include the material choosing and the structure optimizing of heat-sinks, the bonding between the array and the heat-sink, the cooling and the fiber coupling, etc. The status of packaging techniques is stressed. There are basically three different diode package architectural options according to the integration grade. Since the package design is dominated by the cooling aspect, different effective cooling techniques are promoted by different package architectures and specific demands. The benefit and utility of each package are strongly dependent upon the fundamental optoelectronic properties of the individual diode laser bars. Factors which influence these properties are outlined and comparisons of packaging approaches for these materials are made. Modularity of package for special application requirements is an important developing tendency for high power diode lasers.

  20. High power impulse magnetron sputtering discharge

    SciTech Connect

    Gudmundsson, J. T.; Brenning, N.; Lundin, D.; Helmersson, U.

    2012-05-15

    The high power impulse magnetron sputtering (HiPIMS) discharge is a recent addition to plasma based sputtering technology. In HiPIMS, high power is applied to the magnetron target in unipolar pulses at low duty cycle and low repetition frequency while keeping the average power about 2 orders of magnitude lower than the peak power. This results in a high plasma density, and high ionization fraction of the sputtered vapor, which allows better control of the film growth by controlling the energy and direction of the deposition species. This is a significant advantage over conventional dc magnetron sputtering where the sputtered vapor consists mainly of neutral species. The HiPIMS discharge is now an established ionized physical vapor deposition technique, which is easily scalable and has been successfully introduced into various industrial applications. The authors give an overview of the development of the HiPIMS discharge, and the underlying mechanisms that dictate the discharge properties. First, an introduction to the magnetron sputtering discharge and its various configurations and modifications is given. Then the development and properties of the high power pulsed power supply are discussed, followed by an overview of the measured plasma parameters in the HiPIMS discharge, the electron energy and density, the ion energy, ion flux and plasma composition, and a discussion on the deposition rate. Finally, some of the models that have been developed to gain understanding of the discharge processes are reviewed, including the phenomenological material pathway model, and the ionization region model.

  1. Small high cooling power space cooler

    SciTech Connect

    Nguyen, T. V.; Raab, J.; Durand, D.; Tward, E.

    2014-01-29

    The small High Efficiency pulse tube Cooler (HEC) cooler, that has been produced and flown on a number of space infrared instruments, was originally designed to provide cooling of 10 W @ 95 K. It achieved its goal with >50% margin when limited by the 180 W output ac power of its flight electronics. It has also been produced in 2 stage configurations, typically for simultaneously cooling of focal planes to temperatures as low as 35 K and optics at higher temperatures. The need for even higher cooling power in such a low mass cryocooler is motivated by the advent of large focal plane arrays. With the current availability at NGAS of much larger power cryocooler flight electronics, reliable long term operation in space with much larger cooling powers is now possible with the flight proven 4 kg HEC mechanical cooler. Even though the single stage cooler design can be re-qualified for those larger input powers without design change, we redesigned both the linear and coaxial version passive pulse tube cold heads to re-optimize them for high power cooling at temperatures above 130 K while rejecting heat to 300 K. Small changes to the regenerator packing, the re-optimization of the tuned inertance and no change to the compressor resulted in the increased performance at 150 K. The cooler operating at 290 W input power achieves 35 W@ 150 K corresponding to a specific cooling power at 150 K of 8.25 W/W and a very high specific power of 72.5 W/Kg. At these powers the cooler still maintains large stroke, thermal and current margins. In this paper we will present the measured data and the changes to this flight proven cooler that were made to achieve this increased performance.

  2. Silver based batteries for high power applications

    NASA Astrophysics Data System (ADS)

    Karpinski, A. P.; Russell, S. J.; Serenyi, J. R.; Murphy, J. P.

    The present status of silver oxide-zinc technology and applications has been described by Karpinski et al. [A.P. Karpinski, B. Makovetski, S.J. Russell, J.R. Serenyi, D.C. Williams, Silver-Zinc: status of technology and applications, Journal of Power Sources, 80 (1999) 53-60], where the silver-zinc couple is still the preferred choice where high specific energy/energy density, coupled with high specific power/power density are important for high-rate, weight or size/configuration sensitive applications. Perhaps the silver oxide cathode can be considered one of the most versatile electrode materials. When coupled with other anodes and corresponding electrolyte management system, the silver electrode provides for a wide array of electrochemical systems that can be tailored to meet the most demanding, high power requirements. Besides zinc, the most notable include cadmium, iron, metal hydride, and hydrogen electrode for secondary systems, while primary systems include lithium and aluminum. Alloys including silver are also available, such as silver chloride, which when coupled with magnesium or aluminum are primarily used in many seawater applications. The selection and use of these couples is normally the result of a trade-off of many factors. These include performance, safety, risk, reliability, and cost. When high power is required, silver oxide-zinc, silver oxide-aluminum, and silver oxide-lithium are the most energetic. For moderate performance (i.e., lower power), silver oxide-zinc or silver-cadmium would be the system of choice. This paper summarizes the suitability of the silver-based couples, with an emphasis on the silver-zinc system, as primary or rechargeable power sources for high energy/power applications.

  3. Power spectral density specifications for high-power laser systems

    SciTech Connect

    Lawson, J.K.; Aikens, D.A.; English, R.E. Jr.; Wolfe, C.R.

    1996-04-22

    This paper describes the use of Fourier techniques to characterize the transmitted and reflected wavefront of optical components. Specifically, a power spectral density, (PSD), approach is used. High power solid-state lasers exhibit non-linear amplification of specific spatial frequencies. Thus, specifications that limit the amplitude of these spatial frequencies are necessary in the design of these systems. Further, NIF optical components have square, rectangular or irregularly shaped apertures with major dimensions up-to 800 mm. Components with non-circular apertures can not be analyzed correctly with Zernicke polynomials since these functions are an orthogonal set for circular apertures only. A more complete and powerful representation of the optical wavefront can be obtained by Fourier analysis in 1 or 2 dimensions. The PSD is obtained from the amplitude of frequency components present in the Fourier spectrum. The shape of a resultant wavefront or the focal spot of a complex multicomponent laser system can be calculated and optimized using PSDs of the individual optical components which comprise the system. Surface roughness can be calculated over a range of spatial scale-lengths by integrating the PSD. Finally, since the optical transfer function (OTF) of the instruments used to measure the wavefront degrades at high spatial frequencies, the PSD of an optical component is underestimated. We can correct for this error by modifying the PSD function to restore high spatial frequency information. The strengths of PSD analysis are leading us to develop optical specifications incorporating this function for the planned National Ignition Facility (NIF).

  4. Numerical and experimental analysis of spallation phenomena

    NASA Astrophysics Data System (ADS)

    Martin, Alexandre; Bailey, Sean C. C.; Panerai, Francesco; Davuluri, Raghava S. C.; Zhang, Huaibao; Vazsonyi, Alexander R.; Lippay, Zachary S.; Mansour, Nagi N.; Inman, Jennifer A.; Bathel, Brett F.; Splinter, Scott C.; Danehy, Paul M.

    2016-12-01

    The spallation phenomenon was studied through numerical analysis using a coupled Lagrangian particle tracking code and a hypersonic aerothermodynamics computational fluid dynamics solver. The results show that carbon emission from spalled particles results in a significant modification of the gas composition of the post-shock layer. Results from a test campaign at the NASA Langley HYMETS facility are presented. Using an automated image processing of short exposure images, two-dimensional velocity vectors of the spalled particles were calculated. In a 30-s test at 100 W/cm2 of cold-wall heat flux, more than 722 particles were detected, with an average velocity of 110 m/s.

  5. Muon-induced spallation backgrounds in DUNE

    NASA Astrophysics Data System (ADS)

    Zhu, Guanying; Li, Shirley; Beacom, John

    2017-01-01

    Galactic supernovae are rare, just a few per century, so it is important to be prepared. If we are, then the long-baseline detector DUNE could detect thousands of events, compared to the tens from SN 1987A. An important question is backgrounds from muon-induced spallation reactions. We simulate particle energy-loss processes in liquid argon, and compare relevant isotope yields with those in the water-Cherenkov detector SuperK. Our approach will help optimize the design of DUNE and further benefit the study of supernova neutrinos. GZ, SWL, and JFB are supported by NSF Grant PHY-1404311.

  6. Surface modification to prevent oxide scale spallation

    DOEpatents

    Stephens, Elizabeth V; Sun, Xin; Liu, Wenning; Stevenson, Jeffry W; Surdoval, Wayne; Khaleel, Mohammad A

    2013-07-16

    A surface modification to prevent oxide scale spallation is disclosed. The surface modification includes a ferritic stainless steel substrate having a modified surface. A cross-section of the modified surface exhibits a periodic morphology. The periodic morphology does not exceed a critical buckling length, which is equivalent to the length of a wave attribute observed in the cross section periodic morphology. The modified surface can be created using at least one of the following processes: shot peening, surface blasting and surface grinding. A coating can be applied to the modified surface.

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

    SciTech Connect

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

    1994-10-01

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

  8. Moisture-Induced Spallation and Interfacial Hydrogen Embrittlement of Alumina Scales

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2005-01-01

    Thermal expansion mismatch stresses and interfacial sulfur activity are the major factors producing primary Al2O3 scale spallation on high temperature alloys. However, moisture-induced delayed spallation appears as a secondary, but often dramatic, illustration of an additional mechanistic detail. A historical review of delayed failure of alumina scales and TBC s on superalloys is presented herein. Similarities with metallic phenomena suggest that hydrogen embrittlement from ambient humidity, resulting from the reaction Al+3H2O=Al(OH)3+3H(+)+3e(-), is the operative mechanism. This proposal was tested by standard cathodic hydrogen charging in 1N H2SO4, applied to Rene N5 pre-oxidized at 1150 C for 1000 1-hr cycles, and monitored by weight change, induced current, and microstructure. Here cathodic polarization at -2.0 V abruptly stripped mature Al2O3 scales at the oxide-metal interface. Anodic polarization at +2.0 V, however, produced alloy dissolution. Finally, with no applied voltage, the electrolyte alone produced neither scale spallation nor alloy dissolution. These experiments thus highlight the detrimental effects of hydrogen charging on alumina scale adhesion. It is proposed that interfacial hydrogen embrittlement is produced by moist air and is the root cause of both moisture-induced, delayed scale spallation and desktop TBC failures.

  9. Target Systems Overview for the Spallation Neutron Source

    SciTech Connect

    Gabriel, Tony A.; Barnes, John M.; Charlton, Lowell A.; Di Stefano, James; Farrell, Ken; Haines, John; Johnson, Jeffrey O.; Mansur, Louis K.; Pawel, Steve J.; Siman-Tov, Moshe; Taleyarkhan, Rusi; Wendel, Mark W.; McManamy, Thomas J.; Rennich, Mark J.

    2000-10-15

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

  10. The national spallation neutron source target station: A general overview

    SciTech Connect

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

    1997-06-01

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

  11. High-Power, High-Temperature Superconductor Technology Development

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul B.

    2005-01-01

    Since the first discovery of high-temperature superconductors (HTS) 10 years ago, the most promising areas for their applications in microwave systems have been as passive components for communication systems. Soon after the discovery, experiments showed that passive microwave circuits made from HTS material exceeded the performance of conventional devices for low-power applications and could be 10 times as small or smaller. However, for superconducting microwave components, high-power microwave applications have remained elusive until now. In 1996, DuPont and Com Dev Ltd. developed high-power superconducting materials and components for communication applications under a NASA Lewis Research Center cooperative agreement, NCC3-344 "High Power High Temperature Superconductor (HTS) Technology Development." The agreement was cost shared between the Defense Advanced Research Projects Agency's (DARPA) Technology Reinvestment Program Office and the two industrial partners. It has the following objectives: 1) Material development and characterization for high-power HTS applications; 2) Development and validation of generic high-power microwave components; 3) Development of a proof-of-concept model for a high-power six-channel HTS output multiplexer.

  12. Shielding Design of the Spallation Neutron Source (SNS)

    SciTech Connect

    Johnson, J.O.

    1998-09-17

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

  13. High power diode laser Master Oscillator-Power Amplifier (MOPA)

    NASA Technical Reports Server (NTRS)

    Andrews, John R.; Mouroulis, P.; Wicks, G.

    1994-01-01

    High power multiple quantum well AlGaAs diode laser master oscillator - power amplifier (MOPA) systems were examined both experimentally and theoretically. For two pass operation, it was found that powers in excess of 0.3 W per 100 micrometers of facet length were achievable while maintaining diffraction-limited beam quality. Internal electrical-to-optical conversion efficiencies as high as 25 percent were observed at an internal amplifier gain of 9 dB. Theoretical modeling of multiple quantum well amplifiers was done using appropriate rate equations and a heuristic model of the carrier density dependent gain. The model gave a qualitative agreement with the experimental results. In addition, the model allowed exploration of a wider design space for the amplifiers. The model predicted that internal electrical-to-optical conversion efficiencies in excess of 50 percent should be achievable with careful system design. The model predicted that no global optimum design exists, but gain, efficiency, and optical confinement (coupling efficiency) can be mutually adjusted to meet a specific system requirement. A three quantum well, low optical confinement amplifier was fabricated using molecular beam epitaxial growth. Coherent beam combining of two high power amplifiers injected from a common master oscillator was also examined. Coherent beam combining with an efficiency of 93 percent resulted in a single beam having diffraction-limited characteristics. This beam combining efficiency is a world record result for such a system. Interferometric observations of the output of the amplifier indicated that spatial mode matching was a significant factor in the less than perfect beam combining. Finally, the system issues of arrays of amplifiers in a coherent beam combining system were investigated. Based upon experimentally observed parameters coherent beam combining could result in a megawatt-scale coherent beam with a 10 percent electrical-to-optical conversion efficiency.

  14. CLIC RF High Power Production Testing Program

    SciTech Connect

    Syratchev, I.; Riddone, G.; Tantawi, S.G.; /SLAC

    2011-11-02

    The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the impedance of the periodically loaded waveguide and generate RF power for the main linac accelerating structure. The demands on the high power production ({approx} 150 MW) and the needs to transport the 100 A drive beam for about 1 km without losses, makes the PETS design rather unique and the operation very challenging. In the coming year, an intense PETS testing program will be implemented. The target is to demonstrate the full performance of the PETS operation. The testing program overview and test results available to date are presented.

  15. High-frequency-link based power electronics in power systems

    NASA Astrophysics Data System (ADS)

    Sree, Hari

    Power quality has become a serious concern to many utility customers in recent times. Among the many power quality problems, voltage sags are one of the most common and most mischievous, affecting industrial and commercial customers. They are primarily caused by power system faults at the transmission and distribution level, and thus, are mostly unavoidable. Their effect depends on the equipment sensitivities to the magnitude and duration of these sags and each can cost an industry up to few million dollars. To counter these limitations, many solutions at the customer end have been proposed which include Constant Voltage Transformers (CVT's), UPS and line frequency transformer based Dynamic Voltage Restorer (DVR). These approaches have their respective limitations with regard to capabilities, size and cost. This research proposes a new approach to mitigating these voltage sags involving the use of high frequency transformer link. Suitable switching logic and control strategies have been implemented. The proposed approach in a one-phase application is verified with computer simulations and by a hardware proof-of-concept prototype. Application to three-phase system is verified through simulations. Application of high frequency transformers in other utility applications such as active filters and static compensators is also looked at.

  16. High power infrared QCLs: advances and applications

    NASA Astrophysics Data System (ADS)

    Patel, C. Kumar N.

    2012-01-01

    QCLs are becoming the most important sources of laser radiation in the midwave infrared (MWIR) and longwave infrared (LWIR) regions because of their size, weight, power and reliability advantages over other laser sources in the same spectral regions. The availability of multiwatt RT operation QCLs from 3.5 μm to >16 μm with wall plug efficiency of 10% or higher is hastening the replacement of traditional sources such as OPOs and OPSELs in many applications. QCLs can replace CO2 lasers in many low power applications. Of the two leading groups in improvements in QCL performance, Pranalytica is the commercial organization that has been supplying the highest performance QCLs to various customers for over four year. Using a new QCL design concept, the non-resonant extraction [1], we have achieved CW/RT power of >4.7 W and WPE of >17% in the 4.4 μm - 5.0 μm region. In the LWIR region, we have recently demonstrated QCLs with CW/RT power exceeding 1 W with WPE of nearly 10 % in the 7.0 μm-10.0 μm region. In general, the high power CW/RT operation requires use of TECs to maintain QCLs at appropriate operating temperatures. However, TECs consume additional electrical power, which is not desirable for handheld, battery-operated applications, where system power conversion efficiency is more important than just the QCL chip level power conversion efficiency. In high duty cycle pulsed (quasi-CW) mode, the QCLs can be operated without TECs and have produced nearly the same average power as that available in CW mode with TECs. Multiwatt average powers are obtained even in ambient T>70°C, with true efficiency of electrical power-to-optical power conversion being above 10%. Because of the availability of QCLs with multiwatt power outputs and wavelength range covering a spectral region from ~3.5 μm to >16 μm, the QCLs have found instantaneous acceptance for insertion into multitude of defense and homeland security applications, including laser sources for infrared

  17. The Jefferson Lab High Power Light Source

    SciTech Connect

    James R. Boyce

    2006-01-01

    Jefferson Lab has designed, built and operated two high average power free-electron lasers (FEL) using superconducting RF (SRF) technology and energy recovery techniques. Between 1999-2001 Jefferson Lab operated the IR Demo FEL. This device produced over 2 kW in the mid-infrared, in addition to producing world record average powers in the visible (50 W), ultraviolet (10 W) and terahertz range (50 W) for tunable, short-pulse (< ps) light. This FEL was the first high power demonstration of an accelerator configuration that is being exploited for a number of new accelerator-driven light source facilities that are currently under design or construction. The driver accelerator for the IR Demo FEL uses an Energy Recovered Linac (ERL) configuration that improves the energy efficiency and lowers both the capital and operating cost of such devices by recovering most of the power in the spent electron beam after optical power is extracted from the beam. The IR Demo FEL was de-commissioned in late 2001 for an upgraded FEL for extending the IR power to over 10 kW and the ultraviolet power to over 1 kW. The FEL Upgrade achieved 10 kW of average power in the mid-IR (6 microns) in July of 2004, and its IR operation currently is being extended down to 1 micron. In addition, we have demonstrated the capability of on/off cycling and recovering over a megawatt of electron beam power without diminishing machine performance. A complementary UV FEL will come on-line within the next year. This paper presents a summary of the FEL characteristics, user community accomplishments with the IR Demo, and planned user experiments.

  18. The NASA CSTI High Capacity Power Program

    NASA Technical Reports Server (NTRS)

    Winter, Jerry M.

    1991-01-01

    The SP-100 program was established in 1983 by DOD, DOE, and NASA as a joint program to develop the technology necessary for space nuclear power systems for military and civil applications. During 1986 and 1987, the NASA Advanced Technology Program was responsible for maintaining the momentum of promising technology advancement efforts started during Phase 1 of SP-100 and to strengthen, in key areas, the chances for successful development and growth capability of space nuclear reactor power systems for future space applications. In 1988, the NASA Advanced Technology Program was incorporated into NASA's new Civil Space Technology Initiative (CSTI). The CSTI program was established to provide the foundation for technology development in automation and robotics, information, propulsion, and power. The CSTI High Capacity Power Program builds on the technology efforts of the SP-100 program, incorporates the previous NASA advanced technology project, and provides a bridge to the NASA exploration technology programs. The elements of CSTI high capacity power development include conversion systems: Stirling and thermoelectric, thermal management, power management, system diagnostics, and environmental interactions. Technology advancement in all areas, including materials, is required to provide the growth capability, high reliability, and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall program will develop and demonstrate the technology base required to provide a wide range of modular power systems while minimizing the impact of day/night operations as well as attitudes and distance from the Sun. Significant accomplishments in all of the program elements will be discussed, along with revised goals and project timelines recently developed.

  19. The NASA CSTI High Capacity Power Program

    SciTech Connect

    Winter, J.M.

    1994-09-01

    The SP-100 program was established in 1983 by DOD, DOE, and NASA as a joint program to develop the technology necessary for space nuclear power systems for military and civil applications. During 1986 and 1987, the NASA Advanced Technology Program was responsible for maintaining the momentum of promising technology advancement efforts started during Phase I of SP-100 and to strengthen, in key areas, the chances for successful development and growth capability of space nuclear reactor power systems for future space applications. In 1988, the NASA Advanced Technology Program was incorporated into NASA`s new Civil Space Technology Initiative (CSTI). The CSTI program was established to provide the foundation for technology development in automation and robotics, information, propulsion, and power. The CSTI High Capacity Power Program builds on the technology efforts of the SP-100 program, incorporates the previous NASA advanced technology project, and provides a bridge to the NASA exploration technology programs. The elements of CSTI high capacity power development include conversion systems - Stirling and thermoelectric, thermal management, power management, system diagnostics, and environmental interactions. Technology advancement in all areas, including materials, is required to provide the growth capability, high reliability and 7 to 10 years lifetime demanded for future space nuclear power systems. The overall program will develop and demonstrate the technology base required to provide a wide range of modular power systems while minimizing the impact of day/night operation as well as attitudes and distance from the Sun. Significant accomplishments in all of the program elements will be discussed, along with revised goals and project timelines recently developed.

  20. Management of tritium European Spallation Source

    SciTech Connect

    Ene, D.; Andersson, K.; Jensen, M.; Nielsen, S.; Severin, G.

    2015-03-15

    The European Spallation Source (ESS) will produce tritium via spallation and activation processes during operational activities. Within the location of ESS facility in Lund, Sweden site it is mandatory to demonstrate that the management strategy of the produced tritium ensures the compliance with the country regulation criteria. The aim of this paper is to give an overview of the different aspects of the tritium management in ESS facility. Besides the design parameter study of the helium coolant purification system of the target the consequences of the tritium releasing into the environment were also analyzed. Calculations show that the annual release of tritium during the normal operations represents a small fraction from the estimated total dose. However, more refined calculations of migration of activated-groundwater should be performed for higher hydraulic conductivities, with the availability of the results on soil examinations. With the assumption of 100% release of tritium to the atmosphere during the occurring of the extreme accidents, it was found as well that the total dose complies with the constraint. (authors)

  1. NASA GRC High Power Electromagnetic Thruster Program

    NASA Astrophysics Data System (ADS)

    Lapointe, Michael R.; Pencil, Eric J.

    2004-02-01

    Interest in high power electromagnetic propulsion has been revived to support a variety of future space missions, such as platform maneuvering in low earth orbit, cost-effective cargo transport to lunar and Mars bases, asteroid and outer planet sample return, deep space robotic exploration, and piloted missions to Mars and the outer planets. Magnetoplasmadynamic (MPD) thrusters have demonstrated, at the laboratory level, the capacity to process megawatts of electrical power while providing higher thrust densities than current electric propulsion systems. The ability to generate higher thrust densities permits a reduction in the number of thrusters required to perform a given mission and alleviates the system complexity associated with multiple thruster arrays. The specific impulse of an MPD thruster can be optimized to meet given mission requirements, from a few thousand seconds with heavier gas propellants up to 10,000 seconds with hydrogen propellant. In support of NASA space science and human exploration strategic initiatives, Glenn Research Center is developing and testing pulsed, MW-class MPD thrusters as a prelude to long-duration high power thruster tests. The research effort includes numerical modeling of self-field and applied-field MPD thrusters and experimental testing of quasi-steady MW-class MPD thrusters in a high power pulsed thruster facility. This paper provides an overview of the GRC high power electromagnetic thruster program and the pulsed thruster test facility.

  2. Initial observations of cavitation-induced erosion of liquid metal spallation target vessels at the Spallation Neutron Source

    SciTech Connect

    McClintock, David A; Riemer, Bernie; Ferguson, Phillip D; Carroll, Adam J; Dayton, Michael J

    2012-01-01

    During operation of the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory the mechanical properties of the AISI 316L target module are altered by high-energy neutron and proton radiation. The interior surfaces of the target vessel are also damaged by cavitation-induced erosion, which results from repetitive rapid heating of the liquid mercury by high-energy proton beam pulses. Until recently no observations of cavitation-induced erosion were possible for conditions prototypical to the SNS. Post irradiation examination (PIE) of the first and second operational SNS targets was performed to gain insight into the radiation-induced changes in mechanical properties of the 316L target material and the extent of cavitation-induced erosion to the target vessel inner surfaces. Observations of cavitation-induced erosion of the first and second operational SNS target modules are presented here, including images of the target vessel interiors and specimens removed from the target beam-entrance regions.

  3. Technology development for high power induction accelerators

    SciTech Connect

    Birx, D.L.; Reginato, L.L.

    1985-06-11

    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.

  4. High voltage solar cell power generating system

    NASA Technical Reports Server (NTRS)

    Levy, E., Jr.; Opjorden, R. W.; Hoffman, A. C.

    1974-01-01

    A laboratory solar power system regulated by on-panel switches has been delivered for operating high power (3 kW), high voltage (15,000 volt) loads (communication tubes, ion thrusters). The modular system consists of 26 solar arrays, each with an integral light source and cooling system. A typical array contains 2,560 series-connected cells. Each light source consists of twenty 500-watt tungsten iodide lamps providing plus or minus 5 percent uniformity at one solar constant. An array temperature of less than 40 C is achieved using an infrared filter, a water-cooled plate, a vacuum hold-down system, and air flushing.

  5. Prototype Spallation Neutron Source Rotating Target Assembly Final Test Report

    SciTech Connect

    McManamy, Thomas J; Graves, Van; Garmendia, Amaia Zarraoa; Sorda, Fernando; Etxeita, Borja; Rennich, Mark J

    2011-01-01

    A full-scale prototype of an extended vertical shaft, rotating target assembly based on a conceptual target design for a 1 to 3-MW spallation facility was built and tested. Key elements of the drive/coupling assembly implemented in the prototype include high integrity dynamic face seals, commercially available bearings, realistic manufacturing tolerances, effective monitoring and controls, and fail-safe shutdown features. A representative target disk suspended on a 3.5 meter prototypical shaft was coupled with the drive to complete the mechanical tests. Successful operation for 5400 hours confirmed the overall mechanical feasibility of the extended vertical shaft rotating target concept. The prototype system showed no indications of performance deterioration and the equipment did not require maintenance or relubrication.

  6. Preliminary Numerical and Experimental Analysis of the Spallation Phenomenon

    NASA Technical Reports Server (NTRS)

    Martin, Alexandre; Bailey, Sean C. C.; Panerai, Francesco; Davuluri, Raghava S. C.; Vazsonyi, Alexander R.; Zhang, Huaibao; Lippay, Zachary S.; Mansour, Nagi N.; Inman, Jennifer A.; Bathel, Brett F.; Splinter, Scott C.; Danehy, Paul M.

    2015-01-01

    The spallation phenomenon was studied through numerical analysis using a coupled Lagrangian particle tracking code and a hypersonic aerothermodynamics computational fluid dynamics solver. The results show that carbon emission from spalled particles results in a significant modification of the gas composition of the post shock layer. Preliminary results from a test-campaign at the NASA Langley HYMETS facility are presented. Using an automated image processing of high-speed images, two-dimensional velocity vectors of the spalled particles were calculated. In a 30 second test at 100 W/cm2 of cold-wall heat-flux, more than 1300 particles were detected, with an average velocity of 102 m/s, and most frequent observed velocity of 60 m/s.

  7. Industrial high-power diode lasers: reliability, power, and brightness

    NASA Astrophysics Data System (ADS)

    Strohmaier, Stephan; An, Haiyan; Vethake, Thilo

    2012-03-01

    High power semiconductor lasers, single emitters and bars are developing fast. During the last decade key parameters of diode lasers, such as beam quality, power, spatial and spectral brightness, efficiency as well as reliability have been greatly improved. However, often only individual parameters have been optimized, accepting an adverse effect in the other key parameters. For demanding industrial applications in most cases it is not sufficient to achieve a record value in one of the parameters, on the contrary it is necessary to optimize all the mentioned parameters simultaneously. To be able to achieve this objective it is highly advantageous to have insight in the whole process chain, from epitaxial device structure design and growth, wafer processing, mounting, heat sink design, product development and finally the customer needs your final product has to fulfill. In this publication an overview of recent advances in industrial diode lasers at TRUMPF will be highlighted enabling advanced applications for both high end pump sources as well as highest brightness direct diode.

  8. High to ultra-high power electrical energy storage.

    PubMed

    Sherrill, Stefanie A; Banerjee, Parag; Rubloff, Gary W; Lee, Sang Bok

    2011-12-14

    High power electrical energy storage systems are becoming critical devices for advanced energy storage technology. This is true in part due to their high rate capabilities and moderate energy densities which allow them to capture power efficiently from evanescent, renewable energy sources. High power systems include both electrochemical capacitors and electrostatic capacitors. These devices have fast charging and discharging rates, supplying energy within seconds or less. Recent research has focused on increasing power and energy density of the devices using advanced materials and novel architectural design. An increase in understanding of structure-property relationships in nanomaterials and interfaces and the ability to control nanostructures precisely has led to an immense improvement in the performance characteristics of these devices. In this review, we discuss the recent advances for both electrochemical and electrostatic capacitors as high power electrical energy storage systems, and propose directions and challenges for the future. We asses the opportunities in nanostructure-based high power electrical energy storage devices and include electrochemical and electrostatic capacitors for their potential to open the door to a new regime of power energy.

  9. High power electronic devices cooling at minimum ventilation power

    NASA Astrophysics Data System (ADS)

    Fabbri, Giampietro

    2008-01-01

    In the present work, the cooling of a high power electronic device is studied. The device is in contact with a heat dissipator crossed by air. The air motion through the dissipator is forced by a fan whose supplied power is to be minimized. A finite element dynamic model of the dissipator is firstly created, taking geometrical and physical properties into account as well as steady state experimental data. A simplified model is then obtained, which reproduces the time pattern of the maximum dissipator temperature as a response of the thermal flux removed from the electronic device and the mass flow rate of the air. Afterwards, the simplified model is utilized to build a control system which allows the electronic device to be correctly cooled at minimum air ventilation power during transition to steady states. Genetic algorithms are used to find the parameters of the finite element model and of the control system. Some functioning conditions of the electronic device are lastly considered and discussed.

  10. High-power microwave development in Russia

    NASA Astrophysics Data System (ADS)

    Gauthier, Sylvain

    1995-03-01

    This is a survey of Russian research and development in high-power microwave (HPM) sources. It emphasizes those sources of nanoseconds pulse duration time which have potential weapon as well as radar applications. It does not cover the whole range of Russian HPM research and development but concentrates on those aspects which may lead to military applications. Russian investigators have achieved many world firsts in HPM generation; for example, a multiwave Cerenkov generator with a peak output power of 15 gigawatts. Their successes are based on their impressive capability in pulsed power technology which has yielded high-current generators of terawatt peak power. They have transformed the energy of these currents into microwave radiation using tubes of both conventional and novel designs exploiting relativistic electron beams. Recently, the development of high-current mini-accelerators has moved relativistic electron-beam (REB) HPM generation out of the laboratory and enabled the development of deployable military systems with peak powers in the gigawatt range. As a result, they now see development of a REB-based radar systems as one of the most promising directions in radar systems. Details of such a system are described and the implications for HPM weapons are considered.

  11. rf improvements for Spallation Neutron Source H- ion source.

    PubMed

    Kang, Y W; Fuja, R; Goulding, R H; Hardek, T; Lee, S-W; McCarthy, M P; Piller, M C; Shin, K; Stockli, M P; Welton, R F

    2010-02-01

    The Spallation Neutron Source at Oak Ridge National Laboratory is ramping up the accelerated proton beam power to 1.4 MW and just reached 1 MW. The rf-driven multicusp ion source that originates from the Lawrence Berkeley National Laboratory has been delivering approximately 38 mA H(-) beam in the linac at 60 Hz, 0.9 ms. To improve availability, a rf-driven external antenna multicusp ion source with a water-cooled ceramic aluminum nitride (AlN) plasma chamber is developed. Computer modeling and simulations have been made to analyze and optimize the rf performance of the new ion source. Operational statistics and test runs with up to 56 mA medium energy beam transport beam current identify the 2 MHz rf system as a limiting factor in the system availability and beam production. Plasma ignition system is under development by using a separate 13 MHz system. To improve the availability of the rf power system with easier maintenance, we tested a 70 kV isolation transformer for the 80 kW, 6% duty cycle 2 MHz amplifier to power the ion source from a grounded solid-state amplifier.

  12. Ultra high vacuum broad band high power microwave window

    DOEpatents

    Nguyen-Tuong, V.; Dylla, H.F. III

    1997-11-04

    An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost. 5 figs.

  13. Ultra high vacuum broad band high power microwave window

    DOEpatents

    Nguyen-Tuong, Viet; Dylla, III, Henry Frederick

    1997-01-01

    An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost.

  14. Operation of Power Grids with High Penetration of Wind Power

    NASA Astrophysics Data System (ADS)

    Al-Awami, Ali Taleb

    The integration of wind power into the power grid poses many challenges due to its highly uncertain nature. This dissertation involves two main components related to the operation of power grids with high penetration of wind energy: wind-thermal stochastic dispatch and wind-thermal coordinated bidding in short-term electricity markets. In the first part, a stochastic dispatch (SD) algorithm is proposed that takes into account the stochastic nature of the wind power output. The uncertainty associated with wind power output given the forecast is characterized using conditional probability density functions (CPDF). Several functions are examined to characterize wind uncertainty including Beta, Weibull, Extreme Value, Generalized Extreme Value, and Mixed Gaussian distributions. The unique characteristics of the Mixed Gaussian distribution are then utilized to facilitate the speed of convergence of the SD algorithm. A case study is carried out to evaluate the effectiveness of the proposed algorithm. Then, the SD algorithm is extended to simultaneously optimize the system operating costs and emissions. A modified multi-objective particle swarm optimization algorithm is suggested to identify the Pareto-optimal solutions defined by the two conflicting objectives. A sensitivity analysis is carried out to study the effect of changing load level and imbalance cost factors on the Pareto front. In the second part of this dissertation, coordinated trading of wind and thermal energy is proposed to mitigate risks due to those uncertainties. The problem of wind-thermal coordinated trading is formulated as a mixed-integer stochastic linear program. The objective is to obtain the optimal tradeoff bidding strategy that maximizes the total expected profits while controlling trading risks. For risk control, a weighted term of the conditional value at risk (CVaR) is included in the objective function. The CVaR aims to maximize the expected profits of the least profitable scenarios, thus

  15. Power Budget Analysis for High Altitude Airships

    NASA Technical Reports Server (NTRS)

    Choi, Sang H.; Elliott, James R.; King, Glen C.

    2006-01-01

    The High Altitude Airship (HAA) has various potential applications and mission scenarios that require onboard energy harvesting and power distribution systems. The energy source considered for the HAA s power budget is solar photon energy that allows the use of either photovoltaic (PV) cells or advanced thermoelectric (ATE) converters. Both PV cells and an ATE system utilizing high performance thermoelectric materials were briefly compared to identify the advantages of ATE for HAA applications in this study. The ATE can generate a higher quantity of harvested energy than PV cells by utilizing the cascaded efficiency of a three-staged ATE in a tandem mode configuration. Assuming that each stage of ATE material has the figure of merit of 5, the cascaded efficiency of a three-staged ATE system approaches the overall conversion efficiency greater than 60%. Based on this estimated efficiency, the configuration of a HAA and the power utility modules are defined.

  16. Ionospheric Stimulation By High Power Radio Waves

    NASA Astrophysics Data System (ADS)

    Minami, S.; Nishino, M.; Suzuki, Y.; Sato, S.; Tanikawa, T.; Nakamura, Y.; Wong, A. Y.

    1999-01-01

    We have performed an experiment to artificially stimulate the ionosphere using higher power radio waves at the HIPAS (High Power Auroral Stimulation) facility in Alaska. A radio transmission of 2.85 MHz was made at 80 MW (ERP). Diagnostics were made at the other site located 35 km from the transmission site. The results of cross-correlating the excited HF wave and observed with an 8 channel, 30 MHz scanning cosmic radio noise absorption records revealed the excited height of 90 km. Also atmospheric pressure waves observed on the ground show evident propagation of pressure waves which are generated in the ionosphere by the high-power HF wave. The results determine the excitation height of 90 km in the ionosphere and show evidence of the pressure wave coupling between the ionosphere and the lower atmosphere for periods of 10 min

  17. High Average Power, High Energy Short Pulse Fiber Laser System

    SciTech Connect

    Messerly, M J

    2007-11-13

    Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many applications because they offer the promise of high efficiency, compact, robust systems that are turn key. Applications such as cutting, drilling and materials processing, front end systems for high energy pulsed lasers (such as petawatts) and laser based sources of high spatial coherence, high flux x-rays all require high energy short pulses and two of the three of these applications also require high average power. The challenge in creating a high energy chirped pulse fiber laser system is to find a way to scale the output energy while avoiding nonlinear effects and maintaining good beam quality in the amplifier fiber. To this end, our 3-year LDRD program sought to demonstrate a high energy, high average power fiber laser system. This work included exploring designs of large mode area optical fiber amplifiers for high energy systems as well as understanding the issues associated chirped pulse amplification in optical fiber amplifier systems.

  18. Continuous high-power gas lasers

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.

    1979-01-01

    High power gas laser concepts are discussed with emphasis on the role that fluid mechanics has played in their development. Consideration is given to three types of systems: gasdynamic lasers, HF supersonic diffusion lasers, and electric discharge lasers. Flow effects and aerodynamic windows in such lasers are briefly described. Future directions of research are outlined.

  19. CHALLENGES FACING HIGH POWER PROTON ACCELERATORS

    SciTech Connect

    Plum, Michael A

    2013-01-01

    This presentation will provide an overview of the challenges of high power proton accelerators such as SNS, J-PARC, etc., and what we have learned from recent experiences. Beam loss mechanisms and methods to mitigate beam loss will also be discussed.

  20. BEAM INSTRUMENTATION FOR HIGH POWER HADRON BEAMS

    SciTech Connect

    Aleksandrov, Alexander V

    2013-01-01

    This presentation will describe developments in the beam diagnostics which support the understanding and operation of high power hadron accelerators. These include the measurement of large dynamic range transverse and longitudinal beam profiles, beam loss detection, and non-interceptive diagnostics.

  1. Targets for high power neutral beams

    SciTech Connect

    Kim, J.

    1980-01-01

    Stopping high-power, long-pulse beams is fast becoming an engineering challenge, particularly in neutral beam injectors for heating magnetically confined plasmas. A brief review of neutral beam target technology is presented along with heat transfer calculations for some selected target designs.

  2. Mercury target R&D for the Oak Ridge spallation neutron source

    SciTech Connect

    Haines, J.R.; DiStefano, J.; Farrell, K.; Gabriel, T.A.

    1996-06-01

    The conceptual design for the Oak Ridge Spallation Neutron Source (ORSNS) incorporates liquid mercury as its reference target material. A flowing liquid target was selected mainly because of the increased power handling capability possible with the convective transport process. The major reasons for choosing mercury as the liquid target material are because it: (1) is a liquid at room temperature, (2) has good heat transport properties, and (3) has a high atomic number and mass density resulting in high neutron yield and source brightness. Since liquid targets are not widely utilized in presently operating accelerator targets and because of the challenges posed by the intense, pulsed thermal energy deposition ({approximately}20-100 kJ deposited during each 1-10 {mu}s pulse), considerable R&D is planned for the mercury target concept. The key feasibility issue that will be addressed in early R&D efforts are the effects of the thermal shock environment, which will include development and testing of approaches to mitigate these effects. Materials compatiblity and ES&H issues associated with the use of liquid mercury are also of major importance in early R&D efforts. A brief description of the mercury target design concept, results of initial evaluations of its performance characteristics, identification of its critical issues, and an outline of the R&D program aimed at addressing these issues will be presented.

  3. Design and Testing of a Prototype Spallation Neutron Source Rotating Target Assembly

    SciTech Connect

    Rennich, Mark J; McManamy, Thomas J; Graves, Van; Garmendia, Amaia Zarraoa; Sorda, Fernando

    2010-01-01

    The mechanical aspects of an extended vertical shaft rotating target have been evaluated in a full-scale mockup test. A prototype assembly based on a conceptual target design for a 1 to 3-MW spallation facility was built and tested. Key elements of the drive/coupling assembly implemented in the prototype include high integrity dynamic face seals, commercially available bearings, realistic manufacturing tolerances, effective monitoring and controls, and fail-safe shutdown features. A representative target disk suspended on a 3.5 meter prototypical shaft was coupled with the drive to complete the mechanical tests. After1800 hours of operation the test program has confirmed the overall mechanical feasibility of the extended vertical shaft rotating target concept. Precision alignment of the suspended target disk; successful containment of the water and verification of operational stability over the full speed range of 30 to 60 rpm were primary indications the proposed mechanical design is valid for use in a high power target station.

  4. Nuclear Simulation and Radiation Physics Investigations of the Target Station of the European Spallation Neutron Source

    SciTech Connect

    Filges, Detlef; Neef, Ralf-Dieter; Schaal, Hartwig

    2000-10-15

    The European Spallation Neutron Source (ESS) delivers high-intensity pulsed particle beams with 5-MW average beam power at 1.3-GeV incident proton energy. This causes sophisticated demands on material and geometry choices and a very careful optimization of the whole target system. Therefore, complex and detailed particle transport models and computer code systems have been developed and used to study the nuclear assessment of the ESS target system. The purpose here is to describe the methods of calculation mainly based on the Monte Carlo code to show the performance of the ESS target station. The interesting results of the simulations of the mercury target system are as follows: time-dependent neutron flux densities, energy deposition and heating, radioactivity and afterheat, materials damage by radiation, and high-energy source shielding. The results are discussed in great detail. The validity of codes and models, further requirements to improve the methods of calculation, and the status of running and planned experiments are given also.

  5. Preliminary waste management plan of European spallation

    SciTech Connect

    Ene, Daniela

    2013-07-01

    The European Spallation Source (ESS) is the European common effort in designing and building a next generation large-scale user facility for studies of the structure and dynamics of materials. The proposed schematic layout of the ESS facility is based on a linear driver (linac) directing the proton beam (5 MW of 2.5 GeV) of 2.8 ms long pulses with a 20 Hz on a tungsten target where neutrons are produced via spallation reactions. Further the neutrons will be moderated to thermal and sub-thermal energies in a couple of moderators placed around the target. The moderators feed 22 beamlines guiding the neutrons to the scattering instruments, mainly for neutron scattering research, as has been previously mentioned. The objective of this work is to develop a waste management plan for ESS facility. In this respect two important aspects are analyzed. First the present status of the problem is outlined as follow. Estimate types and quantities of waste that the ESS project will generate at different stages: commission, operation, decommissioning were derived using: i) precise Monte Carlo calculations ii) scaling the activity from the operation experience of the existing spallation source installations for waste such it is difficult to predict level of activation or for components of the facility in stage of the preconceptual model. Associated waste treatment/conditioning options and final disposal route were further analyzed in order to define the waste type and packet descriptions in agreement with Swedish regulations and policy. It was found that the compilation of completely new waste type descriptions for qualification of the ESS waste for disposal will be necessary. Particular attention was devoted to 'problematic waste' as Beryllium reflector, C-14 from graphite used as core zone of the beam-dump and collimators or waste arising from the purification systems of both Helium and water cooling circuits. Management of waste on ESS site: collection/segregation systems

  6. High power diode pumped alkali vapor lasers

    NASA Astrophysics Data System (ADS)

    Zweiback, J.; Krupke, B.

    2008-05-01

    Diode pumped alkali lasers have developed rapidly since their first demonstration. These lasers offer a path to convert highly efficient, but relatively low brightness, laser diodes into a single high power, high brightness beam. General Atomics has been engaged in the development of DPALs with scalable architectures. We have examined different species and pump characteristics. We show that high absorption can be achieved even when the pump source bandwidth is several times the absorption bandwidth. In addition, we present experimental results for both potassium and rubidium systems pumped with a 0.2 nm bandwidth alexandrite laser. These data show slope efficiencies of 67% and 72% respectively.

  7. High Average Power Diode Pumped Solid State Lasers: Power Scaling With High Spectral and Spatial Coherence

    DTIC Science & Technology

    2009-03-30

    thulium upper laser level through cross-relaxation [5, 6]. Phosphate glass is also an attractive host for high-power single-frequency 2-µm Tm3+- doped...12, (8), p. 512 (1976) [4] D. G. Lancaster, A. Sabella, A. Hemming, S. Bennetts, S.D. Jackson, “Power-scalable thulium and holmium fibre lasers...efficient high-power thulium -doped germanate glass fiber laser,” Optics Letters, 32, (6), p. 638 (2007) [6] S. Jackson, “Power scaling method for 2-μm

  8. High-power Ka-band amplifier

    NASA Technical Reports Server (NTRS)

    Cormier, R.

    1993-01-01

    Development of a high-power tube suitable to power a Ka-band (34.5-GHz) antenna transmitter located at the Goldstone, California, tracking station is continuing. The University of Maryland Laboratory for Plasma Research and JPL are conducting a joint effort to test the feasibility of phase locking a second-harmonic gyrotron both by direct injection at the output cavity and by using a priming cavity to bunch the electrons in the beam. This article describes several design options and the results of computer simulation testing.

  9. Scaling blackbody laser to high powers

    NASA Technical Reports Server (NTRS)

    Deyoung, R. J.

    1985-01-01

    Lasers pumped by solar heated blackbody cavities have potential for multimegawatt power beaming in space. There are two basic types of blackbody lasers; cavity pumped and transfer system. The transfer system is judged to be more readily scalable to high power. In this system, either N2 or CO is heated by the blackbody cavity then transferred into the laser cavity where CO2 is injected. The N2-CO2 system was demonstrated, but probably has lower efficiency than the CO-CO system. The characteristics of potential transfer laser systems are outlined.

  10. MI high power operation and future plans

    SciTech Connect

    Kourbanis, Ioanis; /Fermilab

    2008-09-01

    Fermilab's Main Injector on acceleration cycles to 120 GeV has been running a mixed mode operation delivering beam to both the antiproton source for pbar production and to the NuMI[1] target for neutrino production since 2005. On January 2008 the slip stacking process used to increase the beam to the pbar target was expanded to include the beam to the NuMI target increasing both the beam intensity and power. The current high power MI operation will be described along with the near future plans.

  11. High Efficiency Microwave Power Amplifier (HEMPA) Design

    NASA Technical Reports Server (NTRS)

    Sims, W. Herbert

    2004-01-01

    This paper will focus on developing an exotic switching technique that enhances the DC-to-RF conversion efficiency of microwave power amplifiers. For years, switching techniques implemented in the 10 kHz to 30 MHz region have resulted in DC-to-RF conversion efficiencies of 90-95-percent. Currently amplifier conversion efficiency, in the 2-3 GHz region approaches, 10-20-percent. Using a combination of analytical modeling and hardware testing, a High Efficiency Microwave Power Amplifier was built that demonstrated conversion efficiencies four to five times higher than current state of the art.

  12. High power bipolar lead-acid batteries

    NASA Technical Reports Server (NTRS)

    Halpert, Gerald; Attia, Alan

    1991-01-01

    The Jet Propulsion Laboratory (JPL), with interest in advanced energy storage systems, is involved in the development of a unique lead acid battery design. This battery utilizes the same combination of lead and lead dioxide active materials present in the automobile starting battery. However, it can provide 2 to 10 times the power while minimizing volume and weight. The typical starting battery is described as a monopolar type using one current collector for both the positive and negative plate of adjacent cells. Specific power as high as 2.5 kW/kg was projected for 30 second periods with as many as 2000 recharge cycles.

  13. Sulfur and Moisture Effects on Alumina Scale and TBC Spallation

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2007-01-01

    cause is related to a hydrogen embrittlement reaction: Al alloy + 3 H2O = Al(OH)3 + 3H(+) + 3e(-). This mechanism is derived from an analogous moisture-induced hydrogen embrittlement mechanism originally shown for Ni3Al and FeAl intermetallics. Consequently, a cathodic hydrogen charging technique was used to demonstrate that electrolytic de-scaling occurs for these otherwise adherent alumina scales formed on Y-doped Rene'N5, in support of hydrogen effects. Finally, some TBC observations are discussed in light of all of the above. Plasma sprayed 8YSZ coatings, produced on PWA1484 without a bond coat, were found to survive more than 1000 1-hr cycles at 1100 C when desulfurized to below 0.1 ppmw. At higher sulfur (1.2 ppmw) levels, moisture sensitivity and delayed TBC failure, referred to as Desk Top Spallation, occurred at just 200 hr. Despite a large degree of scatter, a factor of 5 in life improvement is indicated for desulfurized samples in cyclic furnace tests, confirming the beneficial effect of low sulfur alloys on model TBC systems. (DTS and moisture effects are also observed on commercially applied PVD 7YSZ coatings on Rene'N5+Y with Pt-aluminide bond coats). These types of catastrophic failure were subverted on the model system by segmenting the substrate into a network of 0.010 high ribs, spaced in. apart, prior to plasma spraying. No failures occurred after 1000 cycles at 1150 C or after 2000 cycles at 1100 C, even after water immersion. The benefit is described in terms of elasticity models and a critical buckling stress.

  14. High Power Experiments in VX-10

    NASA Astrophysics Data System (ADS)

    Squire, Jared; Chang-Diaz, Franklin; Araya-Chacon, Gonzalo; Jacobson, Verlin; Glover, Tim; McCaskill, Greg; Vera, Jerry; Baity, Wally; Carter, Mark; Goulding, Rick

    2004-11-01

    In the Advanced Space Propulsion Laboratory VASIMR experiment (VX-10) we have measured a plasma flux to input gas rate ratio near 100power levels up to 10 kW. The plasma source is being developed to supply a dense target with a high degree of ionization for ICRF acceleration of the flow in an expanding magnetic field. An upgrade to 20 kW helicon operations is underway. Recent results at Oak Ridge National Laboratory show enhanced efficiency operation with a high power density, over 5 kW in a 5 cm diameter tube. Our helicon is presently 9 cm in diameter, so comparable power densities will be achieved in VX-10. We have operated with a Boswell double-saddle antenna design with a magnetic cusp just upstream of the antenna. Recently we have converted to a double-helix half-turn antenna. ICRF experiments have been performed as 1.5 kW that show significant plasma flow acceleration, doubling the flow velocity. A 10 kW ICRF upgrade is underway. Results from high total power ( ˜ 30 kW) experiments with this new helicon antenna and ICRF acceleration are presented.

  15. High Power MPD Thruster Performance Measurements

    NASA Technical Reports Server (NTRS)

    LaPointe, Michael R.; Strzempkowski, Eugene; Pencil, Eric

    2004-01-01

    High power magnetoplasmadynamic (MPD) thrusters are being developed as cost effective propulsion systems for cargo transport to lunar and Mars bases, crewed missions to Mars and the outer planets, and robotic deep space exploration missions. Electromagnetic MPD thrusters have demonstrated, at the laboratory level, the ability to process megawatts of electrical power while providing significantly higher thrust densities than electrostatic electric propulsion systems. The ability to generate higher thrust densities permits a reduction in the number of thrusters required to perform a given mission, and alleviates the system complexity associated with multiple thruster arrays. The specific impulse of an MPD thruster can be optimized to meet given mission requirements, from a few thousand seconds with heavier gas propellants up to 10,000 seconds with hydrogen propellant. In support of programs envisioned by the NASA Office of Exploration Systems, Glenn Research Center is developing and testing quasi-steady MW-class MPD thrusters as a prelude to steady state high power thruster tests. This paper provides an overview of the GRC high power pulsed thruster test facility, and presents preliminary performance data for a quasi-steady baseline MPD thruster geometry.

  16. Determination of spallation neutron flux through spectral adjustment techniques

    SciTech Connect

    Mosby, Michelle A.; Engle, Jonathan Ward; Jackman, Kevin Richard; Nortier, Francois Meiring; Birnbaum, Eva R.

    2016-05-30

    The Los Alamos Isotope Production Facility (IPF) creates medical isotopes using a proton beam impinged on a target stack. Spallation neutrons are created in the interaction of the beam with target. The use of these spallation neutrons to produce additional radionuclides has been proposed in this paper. However, the energy distribution and magnitude of the flux is not well understood. Finally, a modified SAND-II spectral adjustment routine has been used with radioactivation foils to determine the differential neutron fluence for these spallation neutrons during a standard IPF production run.

  17. SPALLATION STUDIES ON SHOCK LOADED U-6 WT PCT NB.

    SciTech Connect

    D. TONKS; ET AL

    2001-01-10

    Several spallation experiments have been performed on the 6 wt pct alloy of uranium using gas gun driven normal plate impacts with VISAR instrumentation and soft recovery. The nominal shock pressures achieved were 28, 34, 42, 50, 55, and 82 kbar. This paper will focus on spallation modeling, e.g. using the 1 D characteristics code CHARADE to simulate the free surface particle velocity. The spallation model involves the ductile growth and coalescence of voids. Metallographical examination of recovered samples and details of the experimental apparatus are discussed in a separate paper.

  18. Determination of spallation neutron flux through spectral adjustment techniques

    NASA Astrophysics Data System (ADS)

    Mosby, M. A.; Engle, J. W.; Jackman, K. R.; Nortier, F. M.; Birnbaum, E. R.

    2016-08-01

    The Los Alamos Isotope Production Facility (IPF) creates medical isotopes using a proton beam impinged on a target stack. Spallation neutrons are created in the interaction of the beam with target. The use of these spallation neutrons to produce additional radionuclides has been proposed. However, the energy distribution and magnitude of the flux is not well understood. A modified SAND-II spectral adjustment routine has been used with radioactivation foils to determine the differential neutron fluence for these spallation neutrons during a standard IPF production run.

  19. Lifetime Estimation of High Power White LEDs

    NASA Astrophysics Data System (ADS)

    Ishizaki, Shinya; Kimura, Hideyoshi; Sugimoto, Masaru

    We have developed a high power and long lifetime white LED module which can be used in general lighting applications. Since the materials in the package are very robust at high temperatures, the device can be operated at junction temperatures (Tj) over 250°C. Moreover, the thermal resistance of the package is less than 20°C/W. Therefore the device can be operated at input power as high as 2.4 W, making it possible to shorten the duration of accelerated lifetime tests. An acceleration ratio greater than 100 has been achieved. Assuming a thermally activated degradation process and applying the Arrhenius model, the LED chip lifetime (defined as a 50% reduction in luminous flux) is determined to be 40,000 hours for a Tj of 130°C. The activation energy of the degradation process was determined to be 1.55 eV.

  20. High power DUV lasers for material processing

    NASA Astrophysics Data System (ADS)

    Mimura, Toshio; Kakizaki, Kouji; Oizumi, Hiroaki; Kobayashi, Masakazu; Fujimoto, Junichi; Matsunaga, Takashi; Mizoguchi, Hakaru

    2016-11-01

    A frontier in laser machining has been required by material processing in DUV region because it is hard to get high power solid-state lasers in this spectral region. DUV excimer lasers are the only solution, and now the time has come to examine the new applications of material processing with DUV excimer lasers. The excimer lasers at 193nm and 248nm have been used in the semiconductor manufacturing for long years, and have field-proven stability and reliability. The high photon energy of 6.4 eV at 193nm is expected to interact directly with the chemical bond of hard-machining materials, such as CFRP, diamond and tempered glasses. We report the latest results of material processing by 193nm high power DUV laser.

  1. High power density solid oxide fuel cells

    DOEpatents

    Pham, Ai Quoc; Glass, Robert S.

    2004-10-12

    A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O (LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

  2. High average power linear induction accelerator development

    SciTech Connect

    Bayless, J.R.; Adler, R.J.

    1987-07-01

    There is increasing interest in linear induction accelerators (LIAs) for applications including free electron lasers, high power microwave generators and other types of radiation sources. Lawrence Livermore National Laboratory has developed LIA technology in combination with magnetic pulse compression techniques to achieve very impressive performance levels. In this paper we will briefly discuss the LIA concept and describe our development program. Our goals are to improve the reliability and reduce the cost of LIA systems. An accelerator is presently under construction to demonstrate these improvements at an energy of 1.6 MeV in 2 kA, 65 ns beam pulses at an average beam power of approximately 30 kW. The unique features of this system are a low cost accelerator design and an SCR-switched, magnetically compressed, pulse power system. 4 refs., 7 figs.

  3. High-Power, High-Thrust Ion Thruster (HPHTion)

    NASA Technical Reports Server (NTRS)

    Peterson, Peter Y.

    2015-01-01

    Advances in high-power photovoltaic technology have enabled the possibility of reasonably sized, high-specific power solar arrays. At high specific powers, power levels ranging from 50 to several hundred kilowatts are feasible. Ion thrusters offer long life and overall high efficiency (typically greater than 70 percent efficiency). In Phase I, the team at ElectroDynamic Applications, Inc., built a 25-kW, 50-cm ion thruster discharge chamber and fabricated a laboratory model. This was in response to the need for a single, high-powered engine to fill the gulf between the 7-kW NASA's Evolutionary Xenon Thruster (NEXT) system and a notional 25-kW engine. The Phase II project matured the laboratory model into a protoengineering model ion thruster. This involved the evolution of the discharge chamber to a high-performance thruster by performance testing and characterization via simulated and full beam extraction testing. Through such testing, the team optimized the design and built a protoengineering model thruster. Coupled with gridded ion thruster technology, this technology can enable a wide range of missions, including ambitious near-Earth NASA missions, Department of Defense missions, and commercial satellite activities.

  4. The cryomodule test stand at the European Spallation Source

    SciTech Connect

    Hees, W.; Weisend II, J. G.; Wang, X. L.; Köttig, T.

    2014-01-29

    The European Spallation Source (ESS) is an intergovernmental project building a multidisciplinary research laboratory based upon the world's most powerful neutron source to be built in Lund, Sweden. The ESS will use a linear accelerator which will deliver protons with 5 MW of power to the target at 2.5 GeV with a nominal current of 50 mA. The superconducting part of the linac consists of over 150 niobium cavities cooled with superfluid helium at 2 K. A dedicated cryoplant will supply the cryomodules with single phase helium through an external cryogenic transfer line. The elliptical cavity cryomodules will undergo their site acceptance tests at the ESS cryomodule test stand in Lund. This test stand will use a 4.5 K cryoplant and warm sub-atmospheric compression to supply the 2 K helium. We will show the requirements for the test stand, a layout proposal and discuss the factors determining the required cryogenic capacity, test sequence and schedule.

  5. High-power, high-intensity laser propagation and interactions

    SciTech Connect

    Sprangle, Phillip; Hafizi, Bahman

    2014-05-15

    This paper presents overviews of a number of processes and applications associated with high-power, high-intensity lasers, and their interactions. These processes and applications include: free electron lasers, backward Raman amplification, atmospheric propagation of laser pulses, laser driven acceleration, atmospheric lasing, and remote detection of radioactivity. The interrelated physical mechanisms in the various processes are discussed.

  6. MULTIPULSE - high resolution and high power in one TDEM system

    NASA Astrophysics Data System (ADS)

    Chen, Tianyou; Hodges, Greg; Miles, Philip

    2015-09-01

    An airborne time domain electromagnetic (TEM) system with high resolution and great depth of exploration is desired for geological mapping as well as for mineral exploration. The MULTIPULSE technology enables an airborne TEM system to transmit a high power pulse (a half-sine, for instance) and one or multiple low power pulse(s) (trapezoid or square) within a half-cycle. The high power pulse ensures good depth of exploration and the low power pulse allows a fast transmitter current turn off and earlier off-time measurement thus providing higher frequency signals, which allows higher near-surface resolution and better sensitivity to weak conductors. The power spectrum of the MULTIPULSE waveform comprising a half-sine and a trapezoid pulse clearly shows increased power in the higher frequency range (> ~2.3 kHz) compared to that of a single half-sine waveform. The addition of the low power trapezoid pulse extends the range of the sensitivity 10-fold towards the weak conductors, expanding the geological conductivity range of a system and increasing the scope of its applications. The MULTIPULSE technology can be applied to standard single-pulse airborne TEM systems on both helicopter and fixed-wing. We field tested the HELITEM MULTIPULSE system over a wire-loop in Iroquois Falls, demonstrating the different sensitivity of the high and low power pulses to the overburden and the wire-loop. We also tested both HELITEM and GEOTEM MULTIPULSE systems over a layered oil sand geologic setting in Fort McMurray, Alberta, Canada. The results show comparable shallow geologic resolution of the MULTIPULSE to that of the RESOLVE system while maintaining superior depth of exploration, confirming the increased geological conductivity range of a system employing MULTIPULSE compared to the standard single-pulse systems.

  7. High power induction free electron laser

    NASA Astrophysics Data System (ADS)

    Miller, John L.

    1988-12-01

    Free electron laser (FEL) amplifiers driven by linear induction accelerators have considerable potential for scaling to high average powers. The high electron beam current produces large single pass gain and extraction efficiency, resulting in high peak power. The pulse repetition frequency scaling is limited primarily by accelerator and pulsed power technology. Two FEL experiments have been performed by the Beam Research Program at the Lawrence Livermore National Laboratory (LLNL): The ELF experiment used the 3.5-MeV beam from the Experimental Test Accelerator (ETA) and operated at a wavelength of 8.6 mm. This device achieved an overall single-pass gain of 45 dB, an output power of 1.5 GW, and an extraction efficiency of 35 percent. The microwave beam was confined in a waveguide in the 4-m-long wiggler. The PALADIN experiment uses the 45-MeV beam from the Advanced Test Accelerator and operates at a wavelength of 10.6 micrometers. Using a 15-m long wiggler a single pass gain of 27 dB was produced. Gain guiding was observed to confine the amplified beam within a beam tube that had a Fresnel number less than 1. The results of these experiments have been successfully modeled using a three dimensional particle simulation code. The Program also has ongoing efforts to develop wiggler, pulsed power and induction linac technology. A focus of much of this work is the ETA-II accelerator, which incorporates magnetic pulse compression drivers. One application of ETA-II will be to drive a 1 mm wavelength FEL. The microwave output will be used for a plasma heating experiment.

  8. High Power Induction Free Electron Laser

    NASA Astrophysics Data System (ADS)

    Miller, John L.

    1989-07-01

    Free electron laser (FEL) amplifiers driven by linear induction accelerators have considerable potential for scaling to high average powers. The high electron beam current produces large single pass gain and extraction efficiency, resulting in high peak power. The pulse repetition frequency scaling is limited primarily by accelerator and pulsed power technology. Two FEL experiments have been performed by the Beam Research Program at the Lawrence Livermore National Laboratory (LLNL): The ELF experiment used the 3.5-MeV beam from the Experimental Test Accelerator (ETA) and operated at a wavelength of 8.6 mm. This device achieved an overall single-pass gain of 45 dB, an output power of 1.5 GW, and an extraction efficiency of 35%. The microwave beam was confined in a waveguide in the 4-m-long wiggler. The PALADIN experiment uses the 45-MeV beam from the Advanced Test Accelerator and operates at a wavelength of 10.6 IA. Using a 15-m long wiggler a single pass gain of 27 dB was produced. Gain guiding was observed to confine the amplified beam within a beam tube that had a Fresnel number less than 1. The results of these expriments have been successfully modeled using a three dimensional particle simulation code. The Program also has ongoing efforts to develop wiggler, pulsed power and induction linac technology. A focus of much of this work is the ETA-II accelerator, which incorporates magnetic pulse compression drivers. One application of ETA-II will be to drive a 1 mm wavelength FEL. The microwave output will be used for a plasma heating experiment.

  9. High power THz sources for nonlinear imaging

    SciTech Connect

    Tekavec, Patrick F.; Kozlov, Vladimir G.

    2014-02-18

    Many biological and chemical compounds have unique absorption features in the THz (0.1 - 10 THz) region, making the use of THz waves attractive for imaging in defense, security, biomedical imaging, and monitoring of industrial processes. Unlike optical radiation, THz frequencies can pass through many substances such as paper, clothing, ceramic, etc. with little attenuation. The use of currently available THz systems is limited by lack of highpower, sources as well as sensitive detectors and detector arrays operating at room temperature. Here we present a novel, high power THz source based on intracavity downconverison of optical pulses. The source delivers 6 ps pulses at 1.5 THz, with an average power of >300 μW and peak powers >450 mW. We propose an imaging method based on frequency upconverison that is ideally suited to use the narrow bandwidth and high peak powers produced by the source. By upconverting the THz image to the infrared, commercially available detectors can be used for real time imaging.

  10. High Power UV LED Industrial Curing Systems

    SciTech Connect

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  11. Spallation Neutrons and Pressure SNAP DE-FG02-03ER46085 CLOSE-OUT MAY 2009

    SciTech Connect

    Parise, John B

    2009-05-22

    The purpose of the grant was to build a community of scientist and to draw upon their expertise to design and build the world's first dedicated high pressure beamline at a spallation source - the so called Spallation Neutron And Pressure (SNAP) beamline at the Spallation Neutron Source (SNS) at OAk Ridge NAtional LAboratory. . Key to this endeavor was an annual meeting attended by the instrument design team and the executive committee. The discussions at those meeting set an ambitious agenda for beamline design and construction and highlighted key science areas of interest for the community. This report documents in 4 appendices the deliberations at the annual SNAP meetings and the evolution of the beamline optics from concept to construction. The appendices also contain key science opportunities for extreme conditions research.

  12. Design and development of a prototype 25 kV, 10 A long pulse Marx modulator for high power klystron

    NASA Astrophysics Data System (ADS)

    Acharya, Mahesh; Shrivastava, Purushottam

    2016-02-01

    Research, design, and development of high average power modulators for the proposed Indian Spallation Neutron Source are in progress at Raja Ramanna Centre for Advanced Technology. With this objective, a prototype of 25 kV, 10 A, 1 ms Marx modulator at repetition rate of 1 Hz has been designed and developed which serves as a proof of principle and technology assessment stage for further development of high repetition rate high voltage high average power modulators. Insulated Gate Bipolar Transistor (IGBT) based modules of 2.8 kV switching capability have been used as main modules. The modulator had 8.2% droop in output voltage pulse without any droop compensation circuit. A droop compensation involving 15 corrector modules has been used to reduce the droop up to 1%. We have used IGBT based 250 V switches to realize the corrector module. A microcontroller based control unit was designed and developed for triggering the main and corrector modules. With this control unit, programmable output pulse has been achieved. Electrical isolation between high voltage circuits and control circuit has been achieved by the use of fiber optic based control signal transmission. Output pulses of 1 ms pulse width, 800 ns rise time, and 5 μs fall time have been achieved. The modulator has advantages of modular design, adjustable pulse width, adjustable rise time, and fall time.

  13. Design and development of a prototype 25 kV, 10 A long pulse Marx modulator for high power klystron.

    PubMed

    Acharya, Mahesh; Shrivastava, Purushottam

    2016-02-01

    Research, design, and development of high average power modulators for the proposed Indian Spallation Neutron Source are in progress at Raja Ramanna Centre for Advanced Technology. With this objective, a prototype of 25 kV, 10 A, 1 ms Marx modulator at repetition rate of 1 Hz has been designed and developed which serves as a proof of principle and technology assessment stage for further development of high repetition rate high voltage high average power modulators. Insulated Gate Bipolar Transistor (IGBT) based modules of 2.8 kV switching capability have been used as main modules. The modulator had 8.2% droop in output voltage pulse without any droop compensation circuit. A droop compensation involving 15 corrector modules has been used to reduce the droop up to 1%. We have used IGBT based 250 V switches to realize the corrector module. A microcontroller based control unit was designed and developed for triggering the main and corrector modules. With this control unit, programmable output pulse has been achieved. Electrical isolation between high voltage circuits and control circuit has been achieved by the use of fiber optic based control signal transmission. Output pulses of 1 ms pulse width, 800 ns rise time, and 5 μs fall time have been achieved. The modulator has advantages of modular design, adjustable pulse width, adjustable rise time, and fall time.

  14. Feedthrough terminal for high-power cell

    DOEpatents

    Kaun, T.D.

    1982-05-28

    A feedthrough terminal for a high power electrochemical storage cell providing low resistance coupling to the conductive elements therein while isolating the terminal electrode from the highly corrosive environment within the cell is disclosed. A large diameter, cylindrical copper electrode is enclosed in a stainless steel tube with a BN powder feedthrough seal maintained around the stainless steel tube by means of facing insulative bushings and an outer sleeve. One end of the copper conductor is silver-brazed directly to a flat, butterfly bus bar within the cell, with the adjacent end of the surrounding outer feedthrough sleeve welded to the bus bar. A threaded seal is fixedly positioned on a distal portion of the stainless steel tube immediately adjacent the distal insulative bushing so as to compress the feedthrough seal in tight fitting relation around the stainless steel tube in providing a rugged, leak-proof electrical feedthrough terminal for the power cell.

  15. Lifetime estimation of high power lasers

    NASA Astrophysics Data System (ADS)

    Lu, Guoguang; Huang, Yun; En, Yunfei

    2010-11-01

    We have set up a computer automated controlled diode array reliability experiment which can take up 10 to 20 high power cm-bars. Subsequent 25°C and 50°C lifetime tests were completed. According to the method of least squares, the degradation model of cm-bars is obtained. Using the model and weibull++7 software, the extrapolated lifetime of cmbars at 25°C is 7950 hours (2.86×109 shots). We also obtain an acceleration factor 1.88 of resulting in a thermal activation energy of Ea=0.21eV using Arrhenius function. Finally, failure analysis was carried on the gradually degraded devices, the results show that it is the facet degradation which made high power cm-bars degrade during the long time lifetime test.

  16. Industrial Applications of High Power Ultrasonics

    NASA Astrophysics Data System (ADS)

    Patist, Alex; Bates, Darren

    Since the change of the millennium, high-power ultrasound has become an alternative food processing technology applicable to large-scale commercial applications such as emulsification, homogenization, extraction, crystallization, dewatering, low-temperature pasteurization, degassing, defoaming, activation and inactivation of enzymes, particle size reduction, extrusion, and viscosity alteration. This new focus can be attributed to significant improvements in equipment design and efficiency during the late 1990 s. Like most innovative food processing technologies, high-power ultrasonics is not an off-the-shelf technology, and thus requires careful development and scale-up for each and every application. The objective of this chapter is to present examples of ultrasonic applications that have been successful at the commercialization stage, advantages, and limitations, as well as key learnings from scaling up an innovative food technology in general.

  17. Power Supplies for High Energy Particle Accelerators

    NASA Astrophysics Data System (ADS)

    Dey, Pranab Kumar

    2016-06-01

    The on-going research and the development projects with Large Hadron Collider at CERN, Geneva, Switzerland has generated enormous enthusiasm and interest amongst all to know about the ultimate findings on `God's Particle'. This paper has made an attempt to unfold the power supply requirements and the methodology adopted to provide the stringent demand of such high energy particle accelerators during the initial stages of the search for the ultimate particles. An attempt has also been made to highlight the present status on the requirement of power supplies in some high energy accelerators with a view that, precautionary measures can be drawn during design and development from earlier experience which will be of help for the proposed third generation synchrotron to be installed in India at a huge cost.

  18. High power/large area PV systems

    NASA Technical Reports Server (NTRS)

    Wise, Joseph; Baraona, Cosmo

    1987-01-01

    The major photovoltaic power system technology drivers for a wide variety of mission types were ranked. Each technology driver was ranked on a scale of high, medium, or low in terms of importance to each particular mission type. The rankings were then compiled to determine the overall importance of each driver over the entire range of space missions. In each case cost was ranked the highest.

  19. Low Cost, Low Power, High Sensitivity Magnetometer

    DTIC Science & Technology

    2008-12-01

    Guedes , A.; et al., 2008: Hybrid - LOW COST, LOW POWER, HIGH SENSITIVITY MAGNETOMETER A.S. Edelstein*, James E. Burnette, Greg A. Fischer, M.G...Edelstein, 2004; Burnette, 2008), we suggested a method for mitigating the problem of 1/f noise. We and others ( Guedes , 2008) have been utilizing...6. Guedes , A.; et al., 2008: Hybrid - 3magnetoresistive/microelectromechanical devices for static field modulation and sensor 1/f noise

  20. High-Power Amplifier Free Electron Lasers

    DTIC Science & Technology

    2006-06-01

    society, including laser pointers , printers, compact-disc players, DVD players, product scanners and even as instruments in medical procedures. With...FREE ELECTRON LASERS by Tyrone Y. Voughs June 2006 Thesis Advisor: William B. Colson Co-Advisor: Robert L. Armstead...2006 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE High-Power Amplifier Free Electron Lasers 6. AUTHOR(S) LT Tyrone Y

  1. Improved high-power TSP bits

    SciTech Connect

    Cohen, J.H.; Maurer, W.C.; Westcott, P.A.

    1994-12-31

    Four 3-in. (76.2-mm) diameter experimental bits utilizing large TSP cutters were manufactured in an attempt to develop improved hard rock drill bits. The bits were tested on a 2 3/8-in. (60.3-mm) downhole motor that operated at speeds up to 2,700 rpm and delivered up to 48 hp (36 kW). The TSP bits drilled Batesville marble at rates up to 550 ft/hr (168 m/hr) compared to 50 to 100 ft/hr (15 to 30 m/hr) for conventional roller cone bit drilling in this type of rock. The high penetration rates were achieved because the large cutters cut deep grooves in the rock and there was good clearance beneath the bits due to the large bit/rock standoff distance. None of the large cutters broke during the tests despite the severe drilling conditions and high power levels delivered to the bits, thus overcoming cutter breakage problems experienced with smaller TSP bits on earlier tests. The large cutter TSP bits were capable of operating at much higher power levels than the 48 hp (36 kW) delivered by the drilling motor, showing the need for improved high-power motors for use with these improved TSP bits.

  2. Proceedings of the international workshop on spallation materials technology

    SciTech Connect

    Mansur, L.K.; Ullmaier, H.

    1996-10-01

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

  3. Benchmarking Geant4 for spallation neutron source calculations

    NASA Astrophysics Data System (ADS)

    DiJulio, Douglas D.; Batkov, Konstantin; Stenander, John; Cherkashyna, Nataliia; Bentley, Phillip M.

    2016-09-01

    Geant4 is becoming increasingly used for radiation transport simulations of spallation neutron sources and related components. Historically, the code has seen little usage in this field and it is of general interest to investigate the suitability of Geant4 for such applications. For this purpose, we carried out Geant4 calculations based on simple spallation source geometries and also with the the European Spallation Source Technical Design Report target and moderator configuration. The results are compared to calculations performed with the Monte Carlo N- Particle extended code. The comparisons are carried out over the full spallation neutron source energy spectrum, from sub-eV energies up to thousands of MeV. Our preliminary results reveal that there is generally good agreement between the simulations using both codes. Additionally, we have also implemented a general weight-window generator for Geant4 based applications and present some results of the method applied to the ESS target model.

  4. The future of high power laser techniques

    NASA Astrophysics Data System (ADS)

    Poprawe, Reinhart; Loosen, Peter; Hoffmann, Hans-Dieter

    2007-05-01

    High Power Lasers have been used for years in corresponding applications. Constantly new areas and new processes have been demonstrated, developed and transferred to fruitful use in industry. With the advent of diode pumped solid state lasers in the multi-kW-power regime at beam qualities not far away from the diffraction limit, a new area of applicability has opened. In welding applications speeds could be increased and systems could be developed with higher efficiently leading also to new perspectives for increased productivity, e.g. in combined processing. Quality control is increasingly demanded by the applying industries, however applications still are rare. Higher resolution of coaxial process control systems in time and space combined with new strategies in signal processing could give rise to new applications. The general approach described in this paper emphasizes the fact, that laser applications can be developed more efficiently, more precisely and with higher quality, if the laser radiation is tailored properly to the corresponding application. In applying laser sources, the parameter ranges applicable are by far wider and more flexible compared to heat, mechanical or even electrical energy. The time frame ranges from several fs to continuous wave and this spans approximately 15 orders of magnitude. Spacewise, the foci range from several µm to cm and the resulting intensities suitable for materials processing span eight orders of magnitude from 10 3 to 10 11 W/cm2. In addition to space (power, intensity) and time (pulse) the wavelength can be chosen as a further parameter of optimization. As a consequence, the resulting new applications are vast and can be utilized in almost every market segment of our global economy (Fig. 1). In the past and only partly today, however, this flexibility of laser technology is not exploited in full in materials processing, basically because in the high power regime the lasers with tailored beam properties are not

  5. Production of high power femtosecond terahertz radiation

    SciTech Connect

    Neil, George R.; Carr, G.L.; Gubeli III, Joseph F.; Jordan, K.; Martin, Michael C.; McKinney, Wayne R.; Shinn, Michelle; Tani, Masahiko; Williams, G.P.; Zhang, X.-C.

    2003-07-11

    The terahertz (THz) region of the electromagnetic spectrum is attracting interest for a broad range of applications ranging from diagnosing electron beams to biological imaging. Most sources of short pulse THz radiation utilize excitation of biased semiconductors or electro-optic crystals by high peak power lasers. For example, this was done by using an un-doped InAs wafer irradiated by a femtosecond free-electron laser (FEL) at the Thomas Jefferson National Accelerator Facility. Microwatt levels of THz radiation were detected when excited with FEL pulses at 1.06 mm wavelength and 10W average power. Recently substantially higher powers of femtosecond THz pulses produced by synchrotron emission were extracted from the electron beamline. Calculations and measurements confirm the production of coherent broadband THz radiation from relativistic electrons with an average power of nearly 20W, a world record in this wavelength range by a factor of 10,000. We describe the source, presenting theoretical calculations and their experimental verification. Potential applications of this exciting new source include driving new non-linear phenomena, performing pump-probe studies of dynamical properties of novel materials, and studying molecular vibrations and rotations, low frequency protein motions, phonons, superconductor band gaps, electronic scattering, collective electronic excitations (e.g., charge density waves), and spintronics.

  6. Overview of target systems for the Spallation Neutron Source

    SciTech Connect

    Gabriel, Tony A.; Barnes, John M.; Charlton, Lowell A.; DiStefano, James; Farrell, Ken; Haines, John; Johnson, Jeffrey O.; Mansur, Louis K.; Pawel, Steve J.; Siman-Tov, Moshe; Taleyarkhan, Rusi; Wendel, Mark W.; McManamy, Thomas J.; Rennich, Mark J.

    1997-01-01

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

  7. 9xx high power pump modules

    NASA Astrophysics Data System (ADS)

    Pawlik, Susanne; Sverdlov, Boris; Bättig, Rainer; Schmidt, Berthold; Pfeiffer, Hans-Ulrich; Arlt, Sebastian; Lichtenstein, Norbert; Müller, Jürgen; Troger, Jörg; Valk, Bernd; Harder, Christoph

    2006-02-01

    In this communication we present the characteristics of Bookham's MU7-9xx-01 laser module with multimode fiber output. This latest generation of our multimode modules is designed for light output power of up to 7 W in uncooled operation in the wavelength range between 915 nm and 975 nm. The key element of the module is our new SES8-9xx-01 broad area single emitter. These high power lasers in the 9xx nm wavelength range show a high slope efficiency of up to 1.2 W/A in CW room temperature operation. High efficiency combined with low threshold current and low operation voltage result in a maximum wall plug efficiency of above 65%. Almost 4000 h lifetest data at accelerated conditions are available for the laser diodes. The data give estimated reliability values of below 5 kFIT at operating conditions (between 8 A and 8.5 A injection current at up to 35°C heat sink temperature). The robustness of the new lasers is also illustrated by the fact that no catastrophic mirror damage was observed up to 22.5 W of light output power. The low divergence of the laser beam allows coupling into multimode fiber with 0.15 or 0.22 numerical aperture (NA) with a coupling efficiency above 90% at operation condition. Maximum ex-fiber light output powers of 11.5 W are shown. On module level around 2000 h lifetest data are accumulated without any failure or sign of degradation.

  8. High-Efficiency Microwave Power Amplifier

    NASA Technical Reports Server (NTRS)

    Sims, Williams H.

    2005-01-01

    A high-efficiency power amplifier that operates in the S band (frequencies of the order of a few gigahertz) utilizes transistors operating under class-D bias and excitation conditions. Class-D operation has been utilized at lower frequencies, but, until now, has not been exploited in the S band. Nominally, in class D operation, a transistor is switched rapidly between "on" and "off" states so that at any given instant, it sustains either high current or high voltage, but not both at the same time. In the ideal case of zero "on" resistance, infinite "off" resistance, zero inductance and capacitance, and perfect switching, the output signal would be a perfect square wave. Relative to the traditional classes A, B, and C of amplifier operation, class D offers the potential to achieve greater power efficiency. In addition, relative to class-A amplifiers, class-D amplifiers are less likely to go into oscillation. In order to design this amplifier, it was necessary to derive mathematical models of microwave power transistors for incorporation into a larger mathematical model for computational simulation of the operation of a class-D microwave amplifier. The design incorporates state-of-the-art switching techniques applicable only in the microwave frequency range. Another major novel feature is a transmission-line power splitter/combiner designed with the help of phasing techniques to enable an approximation of a square-wave signal (which is inherently a wideband signal) to propagate through what would, if designed in a more traditional manner, behave as a more severely band-limited device (see figure). The amplifier includes an input, a driver, and a final stage. Each stage contains a pair of GaAs-based field-effect transistors biased in class D. The input signal can range from -10 to +10 dBm into a 50-ohm load. The table summarizes the performances of the three stages

  9. Piezoelectric transformer and modular connections for high power and high voltage power supplies

    NASA Technical Reports Server (NTRS)

    Vazquez Carazo, Alfredo (Inventor)

    2006-01-01

    A modular design for combining piezoelectric transformers is provided for high voltage and high power conversion applications. The input portions of individual piezoelectric transformers are driven for a single power supply. This created the vibration and the conversion of electrical to electrical energy from the input to the output of the transformers. The output portions of the single piezoelectric transformers are combining in series and/or parallel to provide multiple outputs having different rating of voltage and current.

  10. Gate Drive For High Speed, High Power IGBTs

    SciTech Connect

    Nguyen, M.N.; Cassel, R.L.; de Lamare, J.E.; Pappas, G.C.; /SLAC

    2007-06-18

    A new gate drive for high-voltage, high-power IGBTs has been developed for the SLAC NLC (Next Linear Collider) Solid State Induction Modulator. This paper describes the design and implementation of a driver that allows an IGBT module rated at 800A/3300V to switch up to 3000A at 2200V in 3{micro}S with a rate of current rise of more than 10000A/{micro}S, while still being short circuit protected. Issues regarding fast turn on, high de-saturation voltage detection, and low short circuit peak current will be presented. A novel approach is also used to counter the effect of unequal current sharing between parallel chips inside most high-power IGBT modules. It effectively reduces the collector-emitter peak current, and thus protects the IGBT from being destroyed during soft short circuit conditions at high di/dt.

  11. High peak power diode stacks for high energy lasers

    NASA Astrophysics Data System (ADS)

    Negoita, Viorel C.; Vethake, Thilo; Jiang, John; Roff, Robert; Shih, Ming; Duck, Richard; Bauer, Marc; Mite, Roberto; Boucke, Konstantin; Treusch, Georg

    2015-02-01

    High energy solid state lasers are being developed for fusion experiments and other research applications where high energy per pulse is required but the repetition rate is rather low, around 10Hz. We report our results on high peak power diode laser stacks used as optical pumps for these lasers. The stacks are based on 10 mm bars with 4 mm cavity length and 55% fill factor, with peak power exceeding 500 W per bar. These bars are stacked and mounted on a cooler which provides backside cooling and electrical insulation. Currently we mount 25 bars per cooler for a nominal peak power of 12.5 kW, but in principle the mounting scheme can be scaled to a different number of devices depending on the application. Pretesting of these bars before soldering on the cooler enables us to select devices with similar wavelength and thus we maintain tight control of the spectral width (FWHM less than 6 nm). Fine adjustments of the centroid wavelength can be done by means of temperature of the cooling fluid or bias current. The available wavelength range spans from 880 nm to 1000 nm, and the wavelength of the entire assembly of stacks can be controlled to within 0.5 nm of the target value, which makes these stacks suitable for pumping a variety of gain media. The devices are fast axis collimated, with over 95% power being collimated in 6 mrad (full angle). The slow axis divergence is 9° (full angle) for 95% power content.

  12. High-power LEDs for plant cultivation

    NASA Astrophysics Data System (ADS)

    Tamulaitis, Gintautas; Duchovskis, Pavelas; Bliznikas, Zenius; Breive, Kestutis; Ulinskaite, Raimonda; Brazaityte, Ausra; Novickovas, Algirdas; Zukauskas, Arturas; Shur, Michael S.

    2004-10-01

    We report on high-power solid-state lighting facility for cultivation of greenhouse vegetables and on the results of the study of control of photosynthetic activity and growth morphology of radish and lettuce imposed by variation of the spectral composition of illumination. Experimental lighting modules (useful area of 0.22 m2) were designed based on 4 types of high-power light-emitting diodes (LEDs) with emission peaked in red at the wavelengths of 660 nm and 640 nm (predominantly absorbed by chlorophyll a and b for photosynthesis, respectively), in blue at 455 nm (phototropic function), and in far-red at 735 nm (important for photomorphology). Morphological characteristics, chlorophyll and phytohormone concentrations in radish and lettuce grown in phytotron chambers under lighting with different spectral composition of the LED-based illuminator and under illumination by high pressure sodium lamps with an equivalent photosynthetic photon flux density were compared. A well-balanced solid-state lighting was found to enhance production of green mass and to ensure healthy morphogenesis of plants compared to those grown using conventional lighting. We observed that the plant morphology and concentrations of morphologically active phytohormones is strongly affected by the spectral composition of light in the red region. Commercial application of the LED-based illumination for large-scale plant cultivation is discussed. This technology is favorable from the point of view of energy consumption, controllable growth, and food safety but is hindered by high cost of the LEDs. Large scale manufacturing of high-power red AlInGaP-based LEDs emitting at 650 nm and a further decrease of the photon price for the LEDs emitting in the vicinity of the absorption peak of chlorophylls have to be achieved to promote horticulture applications.

  13. Coherently coupled high-power fiber arrays

    NASA Astrophysics Data System (ADS)

    Anderegg, Jesse; Brosnan, Stephen; Cheung, Eric; Epp, Paul; Hammons, Dennis; Komine, Hiroshi; Weber, Mark; Wickham, Michael

    2006-02-01

    A four-element fiber array has demonstrated 470 watts of coherently phased, linearly polarized light energy in a single far-field spot. Each element consists of a single-mode fiber-amplifier chain. Phase control of each element is achieved with a Lithium-Niobate phase modulator. A master laser provides a linearly polarized, narrow linewidth signal that is split into five channels. Four channels are individually amplified using polarization maintaining fiber power amplifiers. The fifth channel is used as a reference arm. It is frequency shifted and then combined interferometrically with a portion of each channel's signal. Detectors sense the heterodyne modulation signal, and an electronics circuit measures the relative phase for each channel. Compensating adjustments are then made to each channel's phase modulator. This effort represents the results of a multi-year effort to achieve high power from a single element fiber amplifier and to understand the important issues involved in coherently combining many individual elements to obtain sufficient optical power for directed energy weapons. Northrop Grumman Corporation and the High Energy Laser Joint Technology Office jointly sponsored this work.

  14. High-power LED package requirements

    NASA Astrophysics Data System (ADS)

    Wall, Frank; Martin, Paul S.; Harbers, Gerard

    2004-01-01

    Power LEDs have evolved from simple indicators into illumination devices. For general lighting applications, where the objective is to light up an area, white LED arrays have been utilized to serve that function. Cost constraints will soon drive the industry to provide a discrete lighting solution. Early on, that will mean increasing the power densities while quantum efficiencies are addressed. For applications such as automotive headlamps & projection, where light needs to be tightly collimated, or controlled, arrays of die or LEDs will not be able to satisfy the requirements & limitations defined by etendue. Ultimately, whether a luminaire requires a small source with high luminance, or light spread over a general area, economics will force the evolution of the illumination LED into a compact discrete high power package. How the customer interfaces with this new package should be an important element considered early on in the design cycle. If an LED footprint of adequate size is not provided, it may prove impossible for the customer, or end user, to get rid of the heat in a manner sufficient to prevent premature LED light output degradation. Therefore it is critical, for maintaining expected LED lifetime & light output, that thermal performance parameters be defined, by design, at the system level, which includes heat sinking methods & interface materials or methdology.

  15. High power ICRF experiments on TFTR

    SciTech Connect

    Wilson, J.R.; Hosea, J.C.; Majeski, R.; Phillips, C.K.; Rogers, J.H.; Schilling, G.; Stevens, J.; Taylor, G. ); Murakami, M.; Rasmussen, D.A. ); TFTR Group

    1994-10-15

    ICRF heating experiments have been conducted in a variety of conditions on the TFTR tokamak. Power levels up to 11.4 MW have been applied. During NBI driven supershot discharges the central electron temperature has been increased from 9 kev to 13 kev via [sup 3]He minority heating with 6 MW of RF power. This temperature increase leads to a 70% increase in the projected alpha energy slowing down time. In gas fueled L-mode discharges the energetic hydrogen minority tail is observed to strongly influence the MHD stability of the discharges. Besides the stabilization of the sawtooth instability previously reported, the destabilization of both the m=1 fishbone and the TAE (toroidal Alfven eigenmode) instabilities have been observed. The TAE instability is accompanied with significant ([similar to]10%) loss of high energy ions and degradation in global confinement time.

  16. The JLab high power ERL light source

    SciTech Connect

    G.R. Neil; C. Behre; S.V. Benson; M. Bevins; G. Biallas; J. Boyce; J. Coleman; L.A. Dillon-Townes; D. Douglas; H.F. Dylla; R. Evans; A. Grippo; D. Gruber; J. Gubeli; D. Hardy; C. Hernandez-Garcia; K. Jordan; M.J. Kelley; L. Merminga; J. Mammosser; W. Moore; N. Nishimori; E. Pozdeyev; J. Preble; R. Rimmer; Michelle D. Shinn; T. Siggins; C. Tennant; R. Walker; G.P. Williams and S. Zhang

    2005-03-19

    A new THz/IR/UV photon source at Jefferson Lab is the first of a new generation of light sources based on an Energy-Recovered, (superconducting) Linac (ERL). The machine has a 160 MeV electron beam and an average current of 10 mA in 75 MHz repetition rate hundred femtosecond bunches. These electron bunches pass through a magnetic chicane and therefore emit synchrotron radiation. For wavelengths longer than the electron bunch the electrons radiate coherently a broadband THz {approx} half cycle pulse whose average brightness is > 5 orders of magnitude higher than synchrotron IR sources. Previous measurements showed 20 W of average power extracted[1]. The new facility offers simultaneous synchrotron light from the visible through the FIR along with broadband THz production of 100 fs pulses with >200 W of average power. The FELs also provide record-breaking laser power [2]: up to 10 kW of average power in the IR from 1 to 14 microns in 400 fs pulses at up to 74.85 MHz repetition rates and soon will produce similar pulses of 300-1000 nm light at up to 3 kW of average power from the UV FEL. These ultrashort pulses are ideal for maximizing the interaction with material surfaces. The optical beams are Gaussian with nearly perfect beam quality. See www.jlab.org/FEL for details of the operating characteristics; a wide variety of pulse train configurations are feasible from 10 microseconds long at high repetition rates to continuous operation. The THz and IR system has been commissioned. The UV system is to follow in 2005. The light is transported to user laboratories for basic and applied research. Additional lasers synchronized to the FEL are also available. Past activities have included production of carbon nanotubes, studies of vibrational relaxation of interstitial hydrogen in silicon, pulsed laser deposition and ablation, nitriding of metals, and energy flow in proteins. This paper will present the status of the system and discuss some of the discoveries we have made

  17. The JLab high power ERL light source

    NASA Astrophysics Data System (ADS)

    Neil, G. R.; Behre, C.; Benson, S. V.; Bevins, M.; Biallas, G.; Boyce, J.; Coleman, J.; Dillon-Townes, L. A.; Douglas, D.; Dylla, H. F.; Evans, R.; Grippo, A.; Gruber, D.; Gubeli, J.; Hardy, D.; Hernandez-Garcia, C.; Jordan, K.; Kelley, M. J.; Merminga, L.; Mammosser, J.; Moore, W.; Nishimori, N.; Pozdeyev, E.; Preble, J.; Rimmer, R.; Shinn, M.; Siggins, T.; Tennant, C.; Walker, R.; Williams, G. P.; Zhang, S.

    2006-02-01

    A new THz/IR/UV photon source at Jefferson Lab is the first of a new generation of light sources based on an Energy-Recovered, (superconducting) Linac (ERL). The machine has a 160 MeV electron beam and an average current of 10 mA in 75 MHz repetition rate hundred femtosecond bunches. These electron bunches pass through a magnetic chicane and therefore emit synchrotron radiation. For wavelengths longer than the electron bunch the electrons radiate coherently a broadband THz ˜ half cycle pulse whose average brightness is >5 orders of magnitude higher than synchrotron IR sources. Previous measurements showed 20 W of average power extracted [Carr, et al., Nature 420 (2002) 153]. The new facility offers simultaneous synchrotron light from the visible through the FIR along with broadband THz production of 100 fs pulses with >200 W of average power. The FELs also provide record-breaking laser power [Neil, et al., Phys. Rev. Lett. 84 (2000) 662]: up to 10 kW of average power in the IR from 1 to 14 μm in 400 fs pulses at up to 74.85 MHz repetition rates and soon will produce similar pulses of 300-1000 nm light at up to 3 kW of average power from the UV FEL. These ultrashort pulses are ideal for maximizing the interaction with material surfaces. The optical beams are Gaussian with nearly perfect beam quality. See www.jlab.org/FEL for details of the operating characteristics; a wide variety of pulse train configurations are feasible from 10 ms long at high repetition rates to continuous operation. The THz and IR system has been commissioned. The UV system is to follow in 2005. The light is transported to user laboratories for basic and applied research. Additional lasers synchronized to the FEL are also available. Past activities have included production of carbon nanotubes, studies of vibrational relaxation of interstitial hydrogen in silicon, pulsed laser deposition and ablation, nitriding of metals, and energy flow in proteins. This paper will present the status of the

  18. Digitally Controlled High Availability Power Supply

    SciTech Connect

    MacNair, David; /SLAC

    2008-09-25

    This paper reports the design and test results on novel topology, high-efficiency, and low operating temperature, 1,320-watt power modules for high availability power supplies. The modules permit parallel operation for N+1 redundancy with hot swap capability. An embedded DSP provides intelligent start-up and shutdown, output regulation, general control and fault detection. PWM modules in the DSP drive the FET switches at 20 to 100 kHz. The DSP also ensures current sharing between modules, synchronized switching, and soft start up for hot swapping. The module voltage and current have dedicated ADCs (>200 kS/sec) to provide pulse-by-pulse output control. A Dual CAN bus interface provides for low cost redundant control paths. Over-rated module components provide high reliability and high efficiency at full load. Low on-resistance FETs replace conventional diodes in the buck regulator. Saturable inductors limit the FET reverse diode current during switching. The modules operate in a two-quadrant mode, allowing bipolar output from complimentary module groups. Controllable, low resistance FETs at the input and output provide fault isolation and allow module hot swapping.

  19. High-power high-brightness semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Botez, D.

    2005-01-01

    Broad-stripe (greater than or equal to 100 microns) diode lasers have achieved CW powers as high as 15W, and wallplug efficiencies as high as 70%. For high coherent power photonic-crystal structures with modulated gain, that is active photonic crystals (APCs), of large index steps have been used, as early as 1988, for effective lateral-mode control range in large-aperture (100-200 microns) devices. Photonic-bandpass (PBP) structures relying on long-range resonant leaky-wave coupling, so called ROW arrays, have allowed stable, near-diffraction-limited beam operation to powers as high as 1.6W CW and 10W peak pulsed. Photonic-bandgap (PBG) structures with a built-in lattice defect, so called ARROW lasers, have provided up to 0.5W CW stable, single-mode power and hold the potential for 1W CW highly reliable single-mode operation. The solution for high-efficiency surface emission, from 2nd-order DFB/DBR lasers, in a single-lobe beam pattern was found in 2000. Single-lobe and single-mode operation in a diffraction-limited beam orthonormal to the chip surface was demonstrated, which opens the way for the realization of 2-D surface-emitting, 2nd-order APCs for the stable generation of watts of CW single-lobe, single-mode power from large 2-D apertures, as well as scalability of such devices at the wafer level.

  20. High Energy Density Sciences with High Power Lasers at SACLA

    NASA Astrophysics Data System (ADS)

    Kodama, Ryosuke

    2013-10-01

    One of the interesting topics on high energy density sciences with high power lasers is creation of extremely high pressures in material. The pressures of more than 0.1 TPa are the energy density corresponding to the chemical bonding energy, resulting in expectation of dramatic changes in the chemical reactions. At pressures of more than TPa, most of material would be melted on the shock Hugoniot curve. However, if the temperature is less than 1eV or lower than a melting point at pressures of more than TPa, novel solid states of matter must be created through a pressured phase transition. One of the interesting materials must be carbon. At pressures of more than TPa, the diamond structure changes to BC and cubic at more than 3TPa. To create such novel states of matter, several kinds of isentropic-like compression techniques are being developed with high power lasers. To explore the ``Tera-Pascal Science,'' now we have a new tool which is an x-ray free electron laser as well as high power lasers. The XFEL will clear the details of the HED states and also efficiently create hot dense matter. We have started a new project on high energy density sciences using an XFEL (SACLA) in Japan, which is a HERMES (High Energy density Revolution of Matter in Extreme States) project.

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

    SciTech Connect

    Gallimore, S.; Nilsson, P.; Sabbagh, P.; Takibayev, A.; Weisend II, J. G.; Beßler, Y.; Klaus, M.

    2014-01-29

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

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

    NASA Astrophysics Data System (ADS)

    Gallimore, S.; Nilsson, P.; Sabbagh, P.; Takibayev, A.; Weisend, J. G., II; Beßler, Y.; Klaus, M.

    2014-01-01

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

  3. Transportable high-energy high-power generator.

    PubMed

    Novac, B M; Smith, I R; Senior, P; Parker, M; Louverdis, G

    2010-05-01

    High-power applications sometimes require a transportable, simple, and robust gigawatt pulsed power generator, and an analysis of various possible approaches shows that one based on a twin exploding wire array is extremely advantageous. A generator based on this technology and used with a high-energy capacitor bank has recently been developed at Loughborough University. An H-configuration circuit is used, with one pair of diagonally opposite arms each comprising a high-voltage ballast inductor and the other pair exploding wire arrays capable of generating voltages up to 300 kV. The two center points of the H configuration provide the output to the load, which is coupled through a high-voltage self-breakdown spark gap, with the entire autonomous source being housed in a metallic container. Experimentally, a load resistance of a few tens of Ohms is provided with an impulse of more than 300 kV, having a rise time of about 140 ns and a peak power of over 1.7 GW. Details of the experimental arrangement and typical results are presented and diagnostic measurements of the current and voltage output are shown to compare well with theoretical predictions based on detailed numerical modeling. Finally, the next stage toward developing a more powerful and energetic transportable source is outlined.

  4. Spallation Neutron Source Accident Terms for Environmental Impact Statement Input

    SciTech Connect

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

    1998-08-01

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

  5. Earthquake Triggering by High Power Electric Pulses

    NASA Astrophysics Data System (ADS)

    Novikov, Victor; Konev, Yuri; Zeigarnik, Vladimir

    2010-05-01

    The study carried out by the Joint Institute for High Temperatures in cooperation with the Institute of Physics of the Earth and the Research Station in Bishkek of Russian Academy of Sciences in 1999-2008 showed a response of weak seismicity at field experiments with electric pulsed power systems, as well as acoustic emission of rock specimens under laboratory conditions on high-power electric current pulses applied to the rocks. It was suggested that the phenomenon discovered may be used in practice for partial release of tectonic stresses in the Earth crust for earthquake hazard mitigation. Nevertheless, the mechanism of the influence of man-made electromagnetic field on the regional seismicity is not clear yet. One of possible cause of the phenomenon may be pore fluid pressure increase in the rocks under stressed conditions due to Joule heat generation by electric current injected into the Earth crust. It is known that increase of pore fluid pressure in the fault zone over a critical pressure of about 0.05 MPa is sufficient to trigger an earthquake if the fault is near the critical state due to accumulated tectonic deformations. Detailed 3D-calculaton of electric current density in the Earth crust of the Northern Tien Shan provided by pulsed electric high-power system connected to grounded electric dipole showed that at the depth of earthquake epicenters (over 5 km) the electric current density is lower than 10-7 A/m2 that is not sufficient for increase of pressure in the fluid-saturated porous geological medium due to Joule heat generation, which may provide formation of cracks resulting in the fault propagation and release of tectonic stresses in the Earth crust. Nevertheless, under certain conditions, when electric current will be injected into the fault through the casing pipes of two deep wells with preliminary injection of conductive fluid into the fault, the current density may be high enough for significant increase of mechanic pressure in the porous two

  6. Power plant of high safety for underground nuclear power station

    SciTech Connect

    Dolgov, V.N.

    1993-12-31

    An ecologically pure, reliable, and economic nuclear power station is based on the use of nuclear power plants with the liquid-metal coolant. This plant with the inherent safety is protected from external influences due to the underground accommodations in geologically stable formations such as granites, cambrian clays, and salt deposits. The design features of this underground plant are described.

  7. Materials irradiation facilities at the high-power Swiss proton accelerator complex

    NASA Astrophysics Data System (ADS)

    Wagner, Werner; Dai, Yong; Glasbrenner, Heike; Aebersold, Hans-Ulrich

    2007-04-01

    Within the Swiss proton accelerator complex at the Paul-Scherrer-Institute (PSI), several irradiation facilities are operated for investigation of materials behavior under high-dose irradiation conditions as well as for neutron activation analysis and isotope production. In LiSoR (liquid solid reaction), a liquid metal loop connected to the 72 MeV proton accelerator Injector 1, steel samples are irradiated while being in contact with flowing lead-bismuth-eutectic (LBE) at elevated temperatures and under tensile stress. In the spallation neutron source SINQ, the STIP program (SINQ Target Irradiation Program) allows materials irradiation under realistic spallation conditions, i.e. in a mixed spectrum of 570 MeV protons and spallation neutrons. Hundreds of samples, mainly austenitic and ferritic-martensitic steels such as 316L, T91 or F82H, were irradiated to doses up to 20 dpa as part of STIP. These also included steel samples in contact with liquid Hg and liquid LBE. MEGAPIE (MEGAwatt PIlot Experiment), a liquid metal target employing LBE, operated in SINQ during the second half of 2006, can be taken as a materials irradiation facility on its own. Adjacent to the target position, SINQ houses a neutron irradiation rabbit system serving activation analysis and isotope production.

  8. Hybrid high power femtosecond laser system

    NASA Astrophysics Data System (ADS)

    Trunov, V. I.; Petrov, V. V.; Pestryakov, E. V.; Kirpichnikov, A. V.

    2006-01-01

    Design of a high-power femtosecond laser system based on hybrid chirped pulse amplification (CPA) technique developed by us is presented. The goal of the hybrid principle is the use of the parametric and laser amplification methods in chirped pulse amplifiers. It makes it possible to amplify the low-cycle pulses with a duration of <= fs to terawatt power with a high contrast and high conversion efficiency of the pump radiation. In a created system the Ti:Sapphire laser with 10 fs pulses at 810 nm and output energy about 1-3 nJ will be used like seed source. The oscillator pulses were stretched to duration of about 500 ps by an all-reflective grating stretcher. Then the stretched pulses are injected into a nondegenerate noncollinear optical parametric amplifier (NOPA) on the two BBO crystals. After amplification in NOPA the residual pump was used in a bow-tie four pass amplifier with hybrid active medium (based on Al II0 3:Ti 3+ and BeAl IIO 4:Ti 3+ crystals). The final stage of the amplification system consists of two channels, namely NIR (820 nm) and short-VIS (410 nm). Numerical simulation has shown that the terawatt level of output power can be achieved also in a short-VIS channel at the pumping of the double-crystal BBO NOPA by the radiation of the fourth harmonic of the Nd:YAG laser at 266 nm. Experimentally parametric amplification in BBO crystals of 30-50 fs pulses were investigated and optimized using SPIDER technique and single-shot autocomelator for the realization of shortest duration 40 fs.

  9. High frequency inductive lamp and power oscillator

    DOEpatents

    MacLennan, Donald A.; Dymond, Jr., Lauren E.; Gitsevich, Aleksandr; Grimm, William G.; Kipling, Kent; Kirkpatrick, Douglas A.; Ola, Samuel A.; Simpson, James E.; Trimble, William C.; Tsai, Peter; Turner, Brian P.

    2001-01-01

    A high frequency inductively coupled electrodeless lamp includes an excitation coil with an effective electrical length which is less than one half wavelength of a driving frequency applied thereto, preferably much less. The driving frequency may be greater than 100 MHz and is preferably as high as 915 MHz. Preferably, the excitation coil is configured as a non-helical, semi-cylindrical conductive surface having less than one turn, in the general shape of a wedding ring. At high frequencies, the current in the coil forms two loops which are spaced apart and parallel to each other. Configured appropriately, the coil approximates a Helmholtz configuration. The lamp preferably utilizes an bulb encased in a reflective ceramic cup with a pre-formed aperture defined therethrough. The ceramic cup may include structural features to aid in alignment and I or a flanged face to aid in thermal management. The lamp head is preferably an integrated lamp head comprising a metal matrix composite surrounding an insulating ceramic with the excitation integrally formed on the ceramic. A novel solid-state oscillator preferably provides RF power to the lamp. The oscillator is a single active element device capable of providing over 70 watts of power at over 70% efficiency. Various control circuits may be employed to adjust the driving frequency of the oscillator.

  10. High power microwave hazard facing smart ammunitions

    NASA Astrophysics Data System (ADS)

    Bohl, J.

    1995-03-01

    The battle field of the present and even more the one in future will be characterized by the use of weapon systems with a high degree of electronics, computers, and sensors, designed and built to keep not only the man out of the loop. But the higher the technology used for smart weapon systems, the more these systems are endangered by numerous sources of hazard. One of those sources is the threat caused by induced or natural electromagnetic fields. These threat factors can be generated by natural, civil and military environment. In principle there are two main applications which must be considered in military applications: Firstly, weapon systems, that is, high power microwave sources as well as intelligent electromagnetic radiation systems to defeat ammunition on the battle field and secondly, the hardening of the own smart ammunition systems and missiles against the interference sources created by the different types of electromagnetic fields. This report will discuss the possible electromagnetic coupling effects on smart ammunition and missiles and their typical interference caused on the electronics and sensor level. Real time 6-DOF simulations show the flight mission which may be compromised depending on the coupled electromagnetic fields. The German MOD has established a research program where smart ammunitions with different seeker systems are investigated in respect of the coupling effects on smart ammunition caused by high power microwaves. This program considers all available resources and know how in Germany. The systems are investigated by analytical, numerical, and experimental methods with passive and activated missiles.

  11. High frequency inductive lamp and power oscillator

    DOEpatents

    MacLennan, Donald A.; Turner, Brian P.; Dolan, James T.; Kirkpatrick, Douglas A.; Leng, Yongzhang

    2000-01-01

    A high frequency inductively coupled electrodeless lamp includes an excitation coil with an effective electrical length which is less than one half wavelength of a driving frequency applied thereto, preferably much less. The driving frequency may be greater than 100 MHz and is preferably as high as 915 MHz. Preferably, the excitation coil is configured as a non-helical, semi-cylindrical conductive surface having less than one turn, in the general shape of a wedding ring. At high frequencies, the current in the coil forms two loops which are spaced apart and parallel to each other. Configured appropriately, the coil approximates a Helmholtz configuration. The lamp preferably utilizes an bulb encased in a reflective ceramic cup with a pre-formed aperture defined therethrough. The ceramic cup may include structural features to aid in alignment and/or a flanged face to aid in thermal management. The lamp head is preferably an integrated lamp head comprising a metal matrix composite surrounding an insulating ceramic with the excitation integrally formed on the ceramic. A novel solid-state oscillator preferably provides RF power to the lamp. The oscillator is a single active element device capable of providing over 70 watts of power at over 70% efficiency. Various control circuits may be employed to match the driving frequency of the oscillator to a plurality of tuning states of the lamp.

  12. High Power Helicon In-Space Thruster

    NASA Astrophysics Data System (ADS)

    Ziemba, Timothy; Slough, John; Winglee, Robert

    2004-11-01

    The High Power Helicon (HPH) under development at the University of Washington has direct application as an electrode-less in-space thruster. Axial and radial plasma probe characteristics show that the plasma is created in and near the helicon coil and is then accelerated in the axial direction downstream away from the HPH. The bulk acceleration of the plasma is believed to be due to a coupling of the plasma electrons to the helicon field, which in turn transfers energy to the ions via an ambipolar electric field with downstream electric potentials of greater than 150 volts having been measured. Time of flight measurements of the plasma transiting downstream show specific impulses near 2000 seconds for Argon with calculated thrust levels near 1 Newton for input powers to the plasma in the tens of kilowatts. Nitrogen and hydrogen propellants have Isp levels of 3000 and 5000 seconds respectfully giving some variability in Isp and thrust level by the choice of propellants. Current work focuses on the determination of the various loss channels and optimization of the system efficiencies at increased output power levels.

  13. Recent progress in high power ultrafast MIXSELs

    NASA Astrophysics Data System (ADS)

    Alfieri, C. G. E.; Waldburger, D.; Link, S. M.; Gini, E.; Golling, M.; Tilma, B. W.; Mangold, M.; Keller, U.

    2016-03-01

    The modelocked integrated external-cavity surface emitting laser (MIXSEL) is the most compact technology of ultrafast semiconductor disk laser, combining in the same epitaxial structure an active region and a saturable absorber for stable and self-starting passive modelocking in a linear straight cavity. Here we present the first MIXSEL structure able to produce sub-300-fs pulses at an average output power of 235 mW and 3.35 GHz pulse repetition rate, resulting in a record-high peak power of 240 W. At 10 GHz repetition rate the same MIXSEL generated 279-fs pulses with 310 mW of average output power. An optimized antireflection coating for dispersion minimization together with a reduced field enhancement inside the structure enabled the sensible improvement and the record performances of this novel MIXSEL. Furthermore, thanks to the development of suitable saturable absorbers with fast recovery dynamics and low saturation fluence, we demonstrate the first entirely MOVPE-grown MIXSEL.

  14. Photovoltaics for high capacity space power systems

    NASA Technical Reports Server (NTRS)

    Flood, Dennis J.

    1988-01-01

    The anticipated energy requirements of future space missions will grow by factors approaching 100 or more, particularly as a permanent manned presence is established in space. The advances that can be expected in solar array performance and lifetime, when coupled with advanced, high energy density storage batteries and/or fuel cells, will continue to make photovoltaic energy conversion a viable power generating option for the large systems of the future. The specific technologies required to satisfy any particular set of power requirements will vary from mission to mission. Nonetheless, in almost all cases the technology push will be toward lighter weight and higher efficiency, whether of solar arrays or storage devices. This paper will describe the content and direction of the current NASA program in space photovoltaic technology. The paper will also discuss projected system level capabilities of photovoltaic power systems in the context of some of the new mission opportunities under study by NASA, such as a manned lunar base, and a manned visit to Mars.

  15. Photovoltaics for high capacity space power systems

    NASA Technical Reports Server (NTRS)

    Flood, Dennis J.

    1988-01-01

    The anticipated energy requirements of future space missions will grow by factors approaching 100 or more, particularly as a permanent manned presence is established in space. The advances that can be expected in solar array performance and lifetime, when coupled with advanced, high energy density storage batteries and/or fuel cells, will continue to make photovoltaic energy conversion a viable power generating option for the large systems of the future. The specific technologies required to satisfy any particular set of power requirements will vary from mission to mission. Nonetheless, in almost all cases the technology push will be toward lighter weight and higher efficiency, whether of solar arrays of storage devices. This paper will describe the content and direction of the current NASA program in space photovoltaic technology. The paper will also discuss projected system level capabilities of photovoltaic power systems in the context of some of the new mission opportunities under study by NASA, such as a manned lunar base, and a manned visit to Mars.

  16. Low power, scalable multichannel high voltage controller

    DOEpatents

    Stamps, James Frederick; Crocker, Robert Ward; Yee, Daniel Dadwa; Dils, David Wright

    2008-03-25

    A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

  17. Low power, scalable multichannel high voltage controller

    DOEpatents

    Stamps, James Frederick; Crocker, Robert Ward; Yee, Daniel Dadwa; Dils, David Wright

    2006-03-14

    A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

  18. High power radio frequency attenuation device

    DOEpatents

    Kerns, Quentin A.; Miller, Harold W.

    1984-01-01

    A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.

  19. High power local ECH in CHS

    SciTech Connect

    Kubo, S.; Idei, H.; Iwase, M.; Ohkubo, K.; Minami, T.; Yamada, I.; Narihara, K.; Tanaka, K.; Wilgen, J.B.; Murakami, M.; Rasumussen, D.A.; Nishimura, K.; Okamura, S.; Matsuoka, K.

    1996-02-01

    Electron cyclotron heating (ECH) experiments with 200 kW and 400 kW gyrotrons at the frequency of 53.2 GHz have been performed in Compact Helical System (CHS). Microwave power from both gyrotrons is transmitted with quasi-optical transmission line and highly focused on the mid-plane of CHS. The main purpose of these experiments is to understand the heating and energy transport mechanisms in CHS at the low collisional regime. The combination of the magnetic field, focal position and polarization enables the investigation of the on/off axis local heating effect with fundamental and second harmonic ECH. {copyright} {ital 1996 American Institute of Physics.}

  20. High power singlemode edge-emitting master oscillator power amplifier

    NASA Technical Reports Server (NTRS)

    O'Brien, S.; Parke, R.; Welch, D. F.; Mehuys, D.; Scifres, D.

    1992-01-01

    An edge-emitting monolithically integrated master oscillator power amplifier (M-MOPA) has been fabricated by integrating a distributed Bragg reflector laser with a 500 microns long single mode amplifier. The M-MOPA contains a strained InGaAs quantum well in the active region and operates at about 981.5 nm in an edge-emitting fashion with maximum powers in excess of 175 mW. Single longitudinal and transverse mode operation is maintained to powers in excess of 110 mW CW.

  1. Cryogenics at the European Spallation Source

    NASA Astrophysics Data System (ADS)

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

    Cryogenics plays an important role at the European Spallation Source, a world class neutron science center, currently under construction in Lund, Sweden. Three principal applications of cryogenics are found at ESS. The SRF cryomodules of the ESS proton linac require cooling at 2 K, 4.5 K and 40 K; the hydrogenmoderator surrounding the target that produces neutrons, requires cooling via 16.5 K helium and LHe is required for many of the scientific instruments. These needs will be met by a set of three cryogenic refrigeration/liquefaction plants and an extensive cryogenic distribution system. Significant progress has been made on the ESS cryogenic system in preparation for the expected first beam on target in 2019. This work includes: funding of industry studies for the accelerator cryoplant, preliminary design of the cryogenic distribution system, investigation of possible in kind contributors and release of the invitation to tender for the accelerator cryoplant.This paper describes the requirements, design solutions and current status of the ESS cryogenic system. The planned recovery of waste heat from the cryogenic plants, a unique aspect of ESS, is described. The procurement of the cryogenic system, expected to be done via a combination of purchase via competitive bids and in kind contributions is also discussed.

  2. Improved cooling design for high power waveguide system

    NASA Astrophysics Data System (ADS)

    Chen, W. C. J.; Hartop, R.

    1981-06-01

    Testing of X band high power components in a traveling wave resonator indicates that this improved cooling design reduces temperature in the waveguide and flange. The waveguide power handling capability and power transmission reliability is increased substantially.

  3. Improved cooling design for high power waveguide system

    NASA Technical Reports Server (NTRS)

    Chen, W. C. J.; Hartop, R.

    1981-01-01

    Testing of X band high power components in a traveling wave resonator indicates that this improved cooling design reduces temperature in the waveguide and flange. The waveguide power handling capability and power transmission reliability is increased substantially.

  4. High power parallel ultrashort pulse laser processing

    NASA Astrophysics Data System (ADS)

    Gillner, Arnold; Gretzki, Patrick; Büsing, Lasse

    2016-03-01

    The class of ultra-short-pulse (USP) laser sources are used, whenever high precession and high quality material processing is demanded. These laser sources deliver pulse duration in the range of ps to fs and are characterized with high peak intensities leading to a direct vaporization of the material with a minimum thermal damage. With the availability of industrial laser source with an average power of up to 1000W, the main challenge consist of the effective energy distribution and disposition. Using lasers with high repetition rates in the MHz region can cause thermal issues like overheating, melt production and low ablation quality. In this paper, we will discuss different approaches for multibeam processing for utilization of high pulse energies. The combination of diffractive optics and conventional galvometer scanner can be used for high throughput laser ablation, but are limited in the optical qualities. We will show which applications can benefit from this hybrid optic and which improvements in productivity are expected. In addition, the optical limitations of the system will be compiled, in order to evaluate the suitability of this approach for any given application.

  5. High average power, high current pulsed accelerator technology

    SciTech Connect

    Neau, E.L.

    1995-05-01

    Which current pulsed accelerator technology was developed during the late 60`s through the late 80`s to satisfy the needs of various military related applications such as effects simulators, particle beam devices, free electron lasers, and as drivers for Inertial Confinement Fusion devices. The emphasis in these devices is to achieve very high peak power levels, with pulse lengths on the order of a few 10`s of nanoseconds, peak currents of up to 10`s of MA, and accelerating potentials of up to 10`s of MV. New which average power systems, incorporating thermal management techniques, are enabling the potential use of high peak power technology in a number of diverse industrial application areas such as materials processing, food processing, stack gas cleanup, and the destruction of organic contaminants. These systems employ semiconductor and saturable magnetic switches to achieve short pulse durations that can then be added to efficiently give MV accelerating, potentials while delivering average power levels of a few 100`s of kilowatts to perhaps many megawatts. The Repetitive High Energy Puled Power project is developing short-pulse, high current accelerator technology capable of generating beams with kJ`s of energy per pulse delivered to areas of 1000 cm{sup 2} or more using ions, electrons, or x-rays. Modular technology is employed to meet the needs of a variety of applications requiring from 100`s of kV to MV`s and from 10`s to 100`s of kA. Modest repetition rates, up to a few 100`s of pulses per second (PPS), allow these machines to deliver average currents on the order of a few 100`s of mA. The design and operation of the second generation 300 kW RHEPP-II machine, now being brought on-line to operate at 2.5 MV, 25 kA, and 100 PPS will be described in detail as one example of the new high average power, high current pulsed accelerator technology.

  6. Early history of high-power lasers

    NASA Astrophysics Data System (ADS)

    Sutton, George W.

    2002-02-01

    This paper gives the history of the invention and development of early high power lasers, to which the author contributed and had personal knowledge. The earliest hint that a high power laser could be built came from the electric CO2-N2-He laser of Javan. It happened that the director of the Avco-Everett Research Laboratory had written his Ph.D. dissertation on the deactivation of the vibrational excitation of N2 in an expanding flow under Edward Teller, then at Columbia Univ. The director then started an in-house project to determine if gain could be achieved in a mixture similar to Javan's by means of a shock tunnel where a shock heated mixture of N2, CO2, and He gas was expanded through a supersonic nozzle into a cavity. This concept was named by the author as the gasdynamic laser (GDL). The paper traces the history of the initial gain measurements, the Mark II laser, the RASTA laser, the Tri-Service laser, its troubles and solutions, the United Technology's XLD gasdynamic laser, and their ALL laser. The history of the coastal Crusader will also be mentioned. Also discussed are the early experiments on a combustion-driven chemical laser, and its subsequent rejection by the director.

  7. High power, electrically tunable quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Slivken, Steven; Razeghi, Manijeh

    2016-02-01

    Mid-infrared laser sources (3-14 μm wavelengths) which have wide spectral coverage and high output power are attractive for many applications. This spectral range contains unique absorption fingerprints of most molecules, including toxins, explosives, and nerve agents. Infrared spectroscopy can also be used to detect important biomarkers, which can be used for medical diagnostics by means of breath analysis. The challenge is to produce a broadband midinfrared source which is small, lightweight, robust, and inexpensive. We are currently investigating monolithic solutions using quantum cascade lasers. A wide gain bandwidth is not sufficient to make an ideal spectroscopy source. Single mode output with rapid tuning is desirable. For dynamic wavelength selection, our group is developing multi-section laser geometries with wide electrical tuning (hundreds of cm-1). These devices are roughly the same size as a traditional quantum cascade lasers, but tuning is accomplished without any external optical components. When combined with suitable amplifiers, these lasers are capable of multi-Watt single mode output powers. This manuscript will describe our current research efforts and the potential for high performance, broadband electrical tuning with the quantum cascade laser.

  8. High-Power Ion Thruster Technology

    NASA Technical Reports Server (NTRS)

    Beattie, J. R.; Matossian, J. N.

    1996-01-01

    Performance data are presented for the NASA/Hughes 30-cm-diam 'common' thruster operated over the power range from 600 W to 4.6 kW. At the 4.6-kW power level, the thruster produces 172 mN of thrust at a specific impulse of just under 4000 s. Xenon pressure and temperature measurements are presented for a 6.4-mm-diam hollow cathode operated at emission currents ranging from 5 to 30 A and flow rates of 4 sccm and 8 sccm. Highly reproducible results show that the cathode temperature is a linear function of emission current, ranging from approx. 1000 C to 1150 C over this same current range. Laser-induced fluorescence (LIF) measurements obtained from a 30-cm-diam thruster are presented, suggesting that LIF could be a valuable diagnostic for real-time assessment of accelerator-arid erosion. Calibration results of laminar-thin-film (LTF) erosion badges with bulk molybdenum are presented for 300-eV xenon, krypton, and argon sputtering ions. Facility-pressure effects on the charge-exchange ion current collected by 8-cm-diam and 30-cm-diam thrusters operated on xenon propellant are presented to show that accel current is nearly independent of facility pressure at low pressures, but increases rapidly under high-background-pressure conditions.

  9. Digitally Controlled High Availability Power Supply

    SciTech Connect

    MacNair, David; /SLAC

    2009-05-07

    This paper will report on the test results of a prototype 1320 watt power module for a high availability power supply. The module will allow parallel operation for N+1 redundancy with hot swap capability. The two quadrant output of each module allows pairs of modules to provide a 4 quadrant (bipolar) operation. Each module employs a novel 4 FET buck regulator arranged in a bridge configuration. Each side of the bridge alternately conducts through a small saturable ferrite that limits the reverse current in the FET body diode during turn off. This allows hard switching of the FETs with low switching losses. The module is designed with over-rated components to provide high reliability and better then 97% efficiency at full load. The modules use a Microchip DSP for control, monitoring, and fault detection. The switching FETS are driven by PWM modules in the DSP at 60 KHz. A Dual CAN bus interface provides for low cost redundant control paths. The DSP will also provide current sharing between modules, synchronized switching, and soft start up for hot swapping. The input and output of each module have low resistance FETs to allow hot swapping and isolation of faulted units.

  10. Fibrous zinc anodes for high power batteries

    NASA Astrophysics Data System (ADS)

    Zhang, X. Gregory

    This paper introduces newly developed solid zinc anodes using fibrous material for high power applications in alkaline and large size zinc-air battery systems. The improved performance of the anodes in these two battery systems is demonstrated. The possibilities for control of electrode porosity and for anode/battery design using fibrous materials are discussed in light of experimental data. Because of its mechanical integrity and connectivity, the fibrous solid anode has good electrical conductivity, mechanical stability, and design flexibility for controlling mass distribution, porosity and effective surface area. Experimental data indicated that alkaline cells made of such anodes can have a larger capacity at high discharging currents than commercially available cells. It showed even greater improvement over commercial cells with a non-conventional cell design. Large capacity anodes for a zinc-air battery have also been made and have shown excellent material utilization at various discharge rates. The zinc-air battery was used to power an electric bicycle and demonstrated good results.

  11. High Power ECR Ion Thruster Discharge Characterization

    NASA Technical Reports Server (NTRS)

    Foster, John E.; Kamhawi, Hani; Haag, Thomas; Carpenter, Christian; Williams, George W.

    2006-01-01

    Electron cyclotron resonance (ECR) based ion thrusters with carbon based ion optics can potentially satisfy lifetime requirements for long duration missions (approximately 10 years) because grid erosion and cathode insert depletion issues are virtually eliminated. Though the ECR plasma discharge has been found to typically operate at slightly higher discharge losses than conventional DC ion thrusters (for high total thruster power applications), the discharge power fraction is small (less than 1 percent at 25 kW). In this regard, the benefits of increased life, low discharge plasma potentials, and reduced complexity are welcome tradeoffs for the associated discharge efficiency decrease. Presented here are results from discharge characterization of a large area ECR plasma source for gridded ion thruster applications. These measurements included load matching efficacy, bulk plasma properties via Langmuir probe, and plasma uniformity as measured using current probes distributed at the exit plane. A high degree of plasma uniformity was observed (flatness greater than 0.9). Additionally, charge state composition was qualitatively evaluated using emission spectroscopy. Plasma induced emission was dominated by xenon ion lines. No doubly charged xenon ions were detected.

  12. Material considerations for high frequency, high power capacitors

    NASA Technical Reports Server (NTRS)

    White, W.; Galperin, I.

    1983-01-01

    Dielectric materials chosen for use in this high frequency, high power capacitor must endure hard vacuum conditions, high currents (up to 125 A rms), and frequencies up to 40 kHz. Temperature requirements for this type of capacitor are that capacitor operation must be efficient up to 125 C. A more stringent requirement for the sold dielectric is that the temperature coefficient of dissipation factor should indicate self stabilization well below 125 C. In addition, the dielectric temperature coefficient of capacitance should be negative.

  13. Material considerations for high frequency, high power capacitors

    NASA Astrophysics Data System (ADS)

    White, W.; Galperin, I.

    1983-10-01

    Dielectric materials chosen for use in this high frequency, high power capacitor must endure hard vacuum conditions, high currents (up to 125 A rms), and frequencies up to 40 kHz. Temperature requirements for this type of capacitor are that capacitor operation must be efficient up to 125 C. A more stringent requirement for the sold dielectric is that the temperature coefficient of dissipation factor should indicate self stabilization well below 125 C. In addition, the dielectric temperature coefficient of capacitance should be negative.

  14. 14 CFR 101.25 - Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Power Rockets and Class 3-Advanced High Power Rockets. 101.25 Section 101.25 Aeronautics and Space... OPERATING RULES MOORED BALLOONS, KITES, AMATEUR ROCKETS AND UNMANNED FREE BALLOONS Amateur Rockets § 101.25 Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets. When...

  15. 14 CFR 101.25 - Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Power Rockets and Class 3-Advanced High Power Rockets. 101.25 Section 101.25 Aeronautics and Space... OPERATING RULES MOORED BALLOONS, KITES, AMATEUR ROCKETS AND UNMANNED FREE BALLOONS Amateur Rockets § 101.25 Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets. When...

  16. 14 CFR 101.25 - Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Power Rockets and Class 3-Advanced High Power Rockets. 101.25 Section 101.25 Aeronautics and Space... OPERATING RULES MOORED BALLOONS, KITES, AMATEUR ROCKETS AND UNMANNED FREE BALLOONS Amateur Rockets § 101.25 Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets. When...

  17. 14 CFR 101.25 - Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Power Rockets and Class 3-Advanced High Power Rockets. 101.25 Section 101.25 Aeronautics and Space... OPERATING RULES MOORED BALLOONS, KITES, AMATEUR ROCKETS AND UNMANNED FREE BALLOONS Amateur Rockets § 101.25 Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets. When...

  18. 14 CFR 101.25 - Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Power Rockets and Class 3-Advanced High Power Rockets. 101.25 Section 101.25 Aeronautics and Space... OPERATING RULES MOORED BALLOONS, KITES, AMATEUR ROCKETS AND UNMANNED FREE BALLOONS Amateur Rockets § 101.25 Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets. When...

  19. High Pressure Microwave Powered UV Light Sources

    NASA Astrophysics Data System (ADS)

    Cekic, M.; Frank, J. D.; Popovic, S.; Wood, C. H.

    1997-10-01

    Industrial microwave powered (*electrodeless*) light sources have been limited to quiescent pressures of 300 Torr of buffer gas and metal- halide fills. Recently developed multi-atmospheric electronegative bu lb fills (noble gas-halide excimers, metal halide) require electric field s for ionization that are often large multiples of the breakdown voltage for air. For these fills an auxiliary ignition system is necessary. The most successful scheme utilizes a high voltage pulse power supply and a novel field emission source. Acting together they create localized condition of pressure reduction and high free electron density. This allows the normal microwave fields to drive this small region into avalanche, ignite the bulb, and heat the plasma to it's operating poin t Standard diagnostic techniques of high density discharges are inapplicable to the excimer bulbs, because of the ionic molecular exci ted state structure and absence of self-absorption. The method for temperature determination is based on the equilibrium population of certain vibrational levels of excimer ionic excited states. Electron d ensity was determined from the measurements of Stark profiles of H_β radiation from a small amount of hydrogen mixed with noble gas and halogens. At the present time, high pressure (Te 0.5eV, ne 3 x 10^17 cm-3) production bulbs produce over 900W of radiation in a 30nm band, centered at 30nm. Similarly, these prototypes when loaded with metal-halide bulb fills produce 1 kW of radiation in 30nm wide bands, centered about the wavelength of interest.

  20. Breakdown phenomena in high power klystrons

    SciTech Connect

    Vlieks, A.E.; Allen, M.A.; Callin, R.S.; Fowkes, W.R.; Hoyt, E.W.; Lebacqz, J.V.; Lee, T.G.

    1988-03-01

    In the course of developing new high peak power klystrons at SLAC, high electric fields in several regions of these devices have become an important source of vacuum breakdown phenomena. In addition, a renewed interest in breakdown phenomena for nanosecond pulse, multi-megavolt per centimeter fields has been sparked by recent R and D work in the area of gigawatt RF sources. The most important regions of electrical breakdown are in the output cavity gap area, the RF ceramic windows, and the gun ceramic insulator. The details of the observed breakdown in these regions, experiments performed to understand the phenomena and solutions found to alleviate the problems will be discussed. Recently experiments have been performed on a new prototype R and D klystron. Peak electric fields across the output cavity gaps of this klystron exceed 2 MV/cm. The effect of peak field duration (i.e. pulse width) on the onset of breakdown have been measured. The pulse widths varied from tens of nanoseconds to microseconds. Results from these experiments will be presented. The failure of ceramic RF windows due to multipactor and puncturing was an important problem to overcome in order that our high power klystrons would have a useful life expectancy. Consequently many studies and tests were made to understand and alleviate window breakdown phenomena. Some of the results in this area, especially the effects of surface coatings, window materials and processing techniques and their effects on breakdown will be discussed. Another important source of klystron failure in the recent past at SLAC has been the puncturing of the high voltage ceramic insulator in the gun region. A way of alleviating this problem has been found although the actual cause of the puncturing is not yet clear. The ''practical'' solution to this breakdown process will be described and a possible mechanism for the puncturing will be presented. 9 refs., 5 figs., 3 tabs.

  1. NON-DESTRUCTIVE THERMAL BARRIER COATING SPALLATION PREDICTION BY A LOADBASED MICRO-INDENTATION TECHNIQUE

    SciTech Connect

    J. M. Tannenbaum; K. Lee; B. S.-J. Kang; M.A. Alvin

    2010-11-18

    Currently, the durability and life cycle of thermal barrier coatings (TBC) applied to gas turbine blades and combustor components are limiting the maximum temperature and subsequent efficiency at which gas turbine engines operate. The development of new materials, coating technologies and evaluation techniques is required if enhanced efficiency is to be achieved. Of the current ceramic coating materials used in gas turbine engines, yttria stabilized zirconia (YSZ) is most prevalent, its low thermal conductivity, high thermal expansion coefficient and outstanding mechanical strength make it ideal for use in TBC systems. However, residual stresses caused by coefficients of thermal expansion mismatches within the TBC system and unstable thermally grown oxides are considered the primary causes for its premature and erratic spallation failure. Through finite element simulations, it is shown that the residual stresses generated within the thermally grown oxide (TGO), bond coat (BC), YSZ and their interfaces create slight variations in indentation unloading surface stiffness response prior to spallation failure. In this research, seven air plasma sprayed and one electron beam physical vapor deposition yttria partially stabilized zirconia TBCs were subjected to isothermal and cyclic loadings at 1100°C. The associated coating degradation was evaluated using a non-destructive multiple partial unloading micro-indentation procedure. The results show that the proposed non-destructive micro-indentation evaluation technique can be an effective and specimenindependent TBC failure prediction tool capable of determining the location of initial spallation failure prior to its actual occurrence.

  2. High-Voltage, High-Power Gaseous Electronics Switch For Electric Grid Power Conversion

    NASA Astrophysics Data System (ADS)

    Sommerer, Timothy J.

    2014-05-01

    We are developing a high-voltage, high-power gas switch for use in low-cost power conversion terminals on the electric power grid. Direct-current (dc) power transmission has many advantages over alternating current (ac) transmission, but at present the high cost of ac-dc power interconversion limits the use of dc. The gas switch we are developing conducts current through a magnetized cold cathode plasma in hydrogen or helium to reach practical current densities > 1 A/cm2. Thermal and sputter damage of the cathode by the incident ion flux is a major technical risk, and is being addressed through use of a ``self-healing'' liquid metal cathode (eg, gallium). Plasma conditions and cathode sputtering loss are estimated by analyzing plasma spectral emission. A particle-in-cell plasma model is used to understand various aspects of switch operation, including the conduction phase (where plasma densities can exceed 1013 cm-3), the switch-open phase (where the high-voltage must be held against gas breakdown on the left side of Paschen's curve), and the switching transitions (especially the opening process, which is initiated by forming an ion-matrix sheath adjacent to a control grid). The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000298.

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

    SciTech Connect

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

    2012-02-15

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

  4. Sexual aggression when power is new: Effects of acute high power on chronically low-power individuals.

    PubMed

    Williams, Melissa J; Gruenfeld, Deborah H; Guillory, Lucia E

    2017-02-01

    Previous theorists have characterized sexually aggressive behavior as an expression of power, yet evidence that power causes sexual aggression is mixed. We hypothesize that power can indeed create opportunities for sexual aggression-but that it is those who chronically experience low power who will choose to exploit such opportunities. Here, low-power men placed in a high-power role showed the most hostility in response to a denied opportunity with an attractive woman (Studies 1 and 2). Chronically low-power men and women given acute power were the most likely to say they would inappropriately pursue an unrequited workplace attraction (Studies 3 and 4). Finally, having power over an attractive woman increased harassment behavior among men with chronic low, but not high, power (Study 5). People who see themselves as chronically denied power appear to have a stronger desire to feel powerful and are more likely to use sexual aggression toward that end. (PsycINFO Database Record

  5. High Energy High Power Battery Exceeding PHEV40 Requirements

    SciTech Connect

    Rempel, Jane

    2016-03-31

    TIAX has developed long-life lithium-ion cells that can meet and exceed the energy and power targets (200Wh/kg and 800W/kg pulse power) set out by DOE for PHEV40 batteries. To achieve these targets, we selected and scaled-up a high capacity version of our proprietary high energy and high power CAM-7® cathode material. We paired the cathode with a blended anode containing Si-based anode material capable of delivering high capacity and long life. Furthermore, we optimized the anode blend composition, cathode and anode electrode design, and selected binder and electrolyte compositions to achieve not only the best performance, but also long life. By implementing CAM-7 with a Si-based blended anode, we built and tested prototype 18650 cells that delivered measured specific energy of 198Wh/kg total energy and 845W/kg at 10% SOC (projected to 220Wh/kg in state-of-the-art 18650 cell hardware and 250Wh/kg in 15Ah pouch cells). These program demonstration cells achieved 90% capacity retention after 500 cycles in on-going cycle life testing. Moreover, we also tested the baseline CAM-7/graphite system in 18650 cells showing that 70% capacity retention can be achieved after ~4000 cycles (20 months of on-going testing). Ultimately, by simultaneously meeting the PHEV40 power and energy targets and providing long life, we have developed a Li-ion battery system that is smaller, lighter, and less expensive than current state-of-the-art Li-ion batteries.

  6. High-power, widely-tunable Cr(2+):ZnSemaster oscillator power amplifier systems.

    PubMed

    Berry, P A; Schepler, K L

    2010-07-05

    We demonstrate high-power Cr(2+):ZnSe master oscillator power amplifier (MOPA) pure continuous wave (CW) laser systems with output power of 14 W and amplifier gain greater than 2X. In addition, we develop a theoretical model for this type of amplification and show single-knob tunability at high powers over 400 nm.

  7. Device for Writing the Time Tail from Spallation Neutron Pulses

    SciTech Connect

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

    2001-01-01

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

  8. Temperature measurements of high power LEDs

    NASA Astrophysics Data System (ADS)

    Badalan (Draghici), Niculina; Svasta, Paul; Drumea, Andrei

    2016-12-01

    Measurement of a LED junction temperature is very important in designing a LED lighting system. Depending on the junction temperature we will be able to determine the type of cooling system and the size of the lighting system. There are several indirect methods for junction temperature measurement. The method used in this paper is based on the thermal resistance model. The aim of this study is to identify the best device that would allow measuring the solder point temperature and the temperature on the lens of power LEDs. For this purpose four devices for measuring temperature on a high-power LED are presented and compared according to the acquired measurements: an infrared thermal camera from FLIR Systems, a multimeter with K type thermocouple (Velleman DVM4200), an infrared-spot based noncontact thermometer (Raynger ST) and a measurement system based on a digital temperature sensor (DS1821 type) connected to a PC. The measurements were conducted on an 18W COB (chip-on-board) LED. The measurement points are the supply terminals and the lens of the LED.

  9. Improved Collectors for High Power Gyrotrons

    SciTech Connect

    Ives, R. Lawrence; Singh, Amarjit; Read, Michael; Borchard, Phillipp; Neilson, Jeff

    2009-05-20

    High power gyrotrons are used for electron cyclotron heating, current drive and parasitic mode suppression in tokamaks for fusion energy research. These devices are crucial for successful operation of many research programs around the world, including the ITER program currently being constructed in France. Recent gyrotron failures resulted from cyclic fatigue of the copper material used to fabricated the collectors. The techniques used to collect the spent beam power is common in many gyrotrons produced around the world. There is serious concern that these tubes may also be at risk from cyclic fatigue. This program addresses the cause of the collector failure. The Phase I program successfully demonstrated feasibility of a mode of operation that eliminates the cyclic operation that caused the failure. It also demonstrated that new material can provide increased lifetime under cyclic operation that could increase the lifetime by more than on order of magnitude. The Phase II program will complete that research and develop a collector that eliminates the fatigue failures. Such a design would find application around the world.

  10. K-band high power latching switch

    NASA Astrophysics Data System (ADS)

    Mlinar, M. J.; Piotrowski, W. S.; Raue, J. E.

    1980-12-01

    A 19 GHz waveguide latching switch with a bandwidth of 1400 MHz and an exceptionally low insertion loss of 0.25 dB was demonstrated. The RF and driver ferrites are separate structures and can be optimized individually. This analysis for each structure is separately detailed. Basically, the RF section features a dual turnstile junction. The circulator consists of a dielectric tube which contains two ferrite rods, and a dielectric spacer separating the ferrite parts along the center of symmetry of the waveguide to form two turnstiles. This subassembly is indexed and locked in the center of symmetry of a uniform junction of three waveguides by the metallic transformers installed in the top and bottom walls of the housing. The switching junction and its actuating circuitry met all RF performance objectives and all shock and vibration requirements with no physical damage or performance degradation. It exceeds thermal requirements by operating over a 100 C temperature range (-44 C to +56 C) and has a high power handling capability allowing up to 100 W of CW input power.

  11. Tagging spallation backgrounds with showers in water Cherenkov detectors

    NASA Astrophysics Data System (ADS)

    Li, Shirley Weishi; Beacom, John F.

    2015-11-01

    Cosmic-ray muons and especially their secondaries break apart nuclei ("spallation") and produce fast neutrons and beta-decay isotopes, which are backgrounds for low-energy experiments. In Super-Kamiokande, these beta decays are the dominant background in 6-18 MeV, relevant for solar neutrinos and the diffuse supernova neutrino background. In a previous paper, we showed that these spallation isotopes are produced primarily in showers, instead of in isolation. This explains an empirical spatial correlation between a peak in the muon Cherenkov light profile and the spallation decay, which Super-Kamiokande used to develop a new spallation cut. However, the muon light profiles that Super-Kamiokande measured are grossly inconsistent with shower physics. We show how to resolve this discrepancy and how to reconstruct accurate profiles of muons and their showers from their Cherenkov light. We propose a new spallation cut based on these improved profiles and quantify its effects. Our results can significantly benefit low-energy studies in Super-Kamiokande, and will be especially important for detectors at shallower depths, like the proposed Hyper-Kamiokande.

  12. High Power Flex-Propellant Arcjet Performance

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.

    2011-01-01

    implied nearly frozen flow in the nozzle and yielded performance ranges of 800-1100 sec for hydrogen and 400-600 sec for ammonia. Inferred thrust-to-power ratios were in the range of 30-10 lbf/MWe for hydrogen and 60-20 lbf/MWe for ammonia. Successful completion of this test series represents a fundamental milestone in the progression of high power arcjet technology, and it is hoped that the results may serve as a reliable touchstone for the future development of MW-class regeneratively-cooled flex-propellant plasma rockets.

  13. High-temperature alloys for high-power thermionic systems

    SciTech Connect

    Shin, Kwang S.; Jacobson, D.L.; D'cruz, L.; Luo, Anhua; Chen, Bor-Ling.

    1990-08-01

    The need for structural materials with useful strength above 1600 k has stimulated interest in refractory-metal alloys. Tungsten possesses an extreme high modulus of elasticity as well as the highest melting temperature among metals, and hence is being considered as one of the most promising candidate materials for high temperature structural applications such as space nuclear power systems. This report is divided into three chapters covering the following: (1) the processing of tungsten base alloys; (2) the tensile properties of tungsten base alloys; and (3) creep behavior of tungsten base alloys. Separate abstracts were prepared for each chapter. (SC)

  14. Development of a 33 kV, 20 A long pulse converter modulator for high average power klystron

    NASA Astrophysics Data System (ADS)

    Reghu, T.; Mandloi, V.; Shrivastava, Purushottam

    2014-05-01

    Research, design, and development of high average power, long pulse modulators for the proposed Indian Spallation Neutron Source are underway at Raja Ramanna Centre for Advanced Technology. With this objective, a prototype of long pulse modulator capable of delivering 33 kV, 20 A at 5 Hz repetition rate has been designed and developed. Three Insulated Gate Bipolar Transistors (IGBT) based switching modules driving high frequency, high voltage transformers have been used to generate high voltage output. The IGBT based switching modules are shifted in phase by 120° with respect to each other. The switching frequency is 25 kHz. Pulses of 1.6 ms pulse width, 80 μs rise time, and 70 μs fall time have been achieved at the modulator output. A droop of ±0.6% is achieved using a simple segmented digital droop correction technique. The total fault energy transferred to the load during fault has been measured by conducting wire burn tests and is found to be within 3.5 J.

  15. Development of a 33 kV, 20 A long pulse converter modulator for high average power klystron.

    PubMed

    Reghu, T; Mandloi, V; Shrivastava, Purushottam

    2014-05-01

    Research, design, and development of high average power, long pulse modulators for the proposed Indian Spallation Neutron Source are underway at Raja Ramanna Centre for Advanced Technology. With this objective, a prototype of long pulse modulator capable of delivering 33 kV, 20 A at 5 Hz repetition rate has been designed and developed. Three Insulated Gate Bipolar Transistors (IGBT) based switching modules driving high frequency, high voltage transformers have been used to generate high voltage output. The IGBT based switching modules are shifted in phase by 120° with respect to each other. The switching frequency is 25 kHz. Pulses of 1.6 ms pulse width, 80 μs rise time, and 70 μs fall time have been achieved at the modulator output. A droop of ±0.6% is achieved using a simple segmented digital droop correction technique. The total fault energy transferred to the load during fault has been measured by conducting wire burn tests and is found to be within 3.5 J.

  16. Development of a 33 kV, 20 A long pulse converter modulator for high average power klystron

    SciTech Connect

    Reghu, T.; Mandloi, V.; Shrivastava, Purushottam

    2014-05-15

    Research, design, and development of high average power, long pulse modulators for the proposed Indian Spallation Neutron Source are underway at Raja Ramanna Centre for Advanced Technology. With this objective, a prototype of long pulse modulator capable of delivering 33 kV, 20 A at 5 Hz repetition rate has been designed and developed. Three Insulated Gate Bipolar Transistors (IGBT) based switching modules driving high frequency, high voltage transformers have been used to generate high voltage output. The IGBT based switching modules are shifted in phase by 120° with respect to each other. The switching frequency is 25 kHz. Pulses of 1.6 ms pulse width, 80 μs rise time, and 70 μs fall time have been achieved at the modulator output. A droop of ±0.6% is achieved using a simple segmented digital droop correction technique. The total fault energy transferred to the load during fault has been measured by conducting wire burn tests and is found to be within 3.5 J.

  17. High power solid state laser modulator

    DOEpatents

    Birx, Daniel L.; Ball, Don G.; Cook, Edward G.

    2004-04-27

    A multi-stage magnetic modulator provides a pulse train of .+-.40 kV electrical pulses at a 5-7 kHz repetition rate to a metal vapor laser. A fractional turn transformer steps up the voltage by a factor of 80 to 1 and magnetic pulse compression is used to reduce the pulse width of the pulse train. The transformer is fabricated utilizing a rod and plate stack type of construction to achieve a high packing factor. The pulses are controlled by an SCR stack where a plurality of SCRs are electrically connected in parallel, each SCR electrically connected to a saturable inductor, all saturable inductors being wound on the same core of magnetic material for enhanced power handling characteristics.

  18. Modulation instability in high power laser amplifiers.

    PubMed

    Rubenchik, Alexander M; Turitsyn, Sergey K; Fedoruk, Michail P

    2010-01-18

    The modulation instability (MI) is one of the main factors responsible for the degradation of beam quality in high-power laser systems. The so-called B-integral restriction is commonly used as the criteria for MI control in passive optics devices. For amplifiers the adiabatic model, assuming locally the Bespalov-Talanov expression for MI growth, is commonly used to estimate the destructive impact of the instability. We present here the exact solution of MI development in amplifiers. We determine the parameters which control the effect of MI in amplifiers and calculate the MI growth rate as a function of those parameters. The safety range of operational parameters is presented. The results of the exact calculations are compared with the adiabatic model, and the range of validity of the latest is determined. We demonstrate that for practical situations the adiabatic approximation noticeably overestimates MI. The additional margin of laser system design is quantified.

  19. Frequency stable high power lasers in space

    NASA Technical Reports Server (NTRS)

    Byer, Robert L.

    1989-01-01

    The concept of a laser heterodyne gravity wave antenna that would operate in solar orbit with a one million kilometer path length is discussed. Laser technology that would be appropriate for operation of this space-based gravity wave detector is also discussed. The rapid progress in diode laser coupled with the energy storage and potentially sub-Hertz linewidths of solid state lasers, and the possibility of efficient frequency conversion by nonlinear optical techniques defines a technology that is appropriate for laser interferometry in space. The present status of diode-laser-pumped, solid state lasers is summarized and future progress is projected in areas of linewidth control, high average power, operating efficiency, and operational lifetimes that are essential for space-based applications.

  20. High power coherent polarization locked laser diode.

    PubMed

    Purnawirman; Phua, P B

    2011-03-14

    We have coherently combined a broad area laser diode array to obtain high power single-lobed output by using coherent polarization locking. The single-lobed coherent beam is achieved by spatially combining four diode emitters using walk-off crystals and waveplates while their phases are passively locked via polarization discrimination. While our previous work focused on coherent polarization locking of diode in Gaussian beams, we demonstrate in this paper, the feasibility of the same polarization discrimination for locking multimode beams from broad area diode lasers. The resonator is designed to mitigate the loss from smile effect by using retro-reflection feedback in the cavity. In a 980 nm diode array, we produced 7.2 W coherent output with M2 of 1.5x11.5. The brightness of the diode is improved by more than an order of magnitude.

  1. Highly symmetric POVMs and their informational power

    NASA Astrophysics Data System (ADS)

    Słomczyński, Wojciech; Szymusiak, Anna

    2016-01-01

    We discuss the dependence of the Shannon entropy of normalized finite rank-1 POVMs on the choice of the input state, looking for the states that minimize this quantity. To distinguish the class of measurements where the problem can be solved analytically, we introduce the notion of highly symmetric POVMs and classify them in dimension 2 (for qubits). In this case, we prove that the entropy is minimal, and hence, the relative entropy (informational power) is maximal, if and only if the input state is orthogonal to one of the states constituting a POVM. The method used in the proof, employing the Michel theory of critical points for group action, the Hermite interpolation, and the structure of invariant polynomials for unitary-antiunitary groups, can also be applied in higher dimensions and for other entropy-like functions. The links between entropy minimization and entropic uncertainty relations, the Wehrl entropy, and the quantum dynamical entropy are described.

  2. Facet engineering of high power single emitters

    NASA Astrophysics Data System (ADS)

    Yanson, Dan; Levi, Moshe; Shamay, Moshe; Tesler, Renana; Rappaport, Noam; Don, Yaroslav; Karni, Yoram; Schnitzer, Itzhak; Sicron, Noam; Shusterman, Sergey

    2011-03-01

    The ever increasing demand for high-power, high-reliability operation of single emitters at 9xx nm wavelengths requires the development of laser diodes with improved facet regions immune to both catastrophic and wear-out failure modes. In our study, we have evaluated several laser facet definition technologies in application to 90 micron aperture single emitters in asymmetric design (In)GaAs/AlGaAs based material emitting at 915, 925 and 980nm. A common epitaxy and emitter design makes for a straightforward comparison of the facet technologies investigated. Our study corroborates a clear trend of increasing difficulty in obtaining reliable laser operation from 980nm down to 915nm. At 980nm, one can employ dielectric facet passivation with a pre-clean cycle delivering a device lifetime in excess of 3,000 hours at increasing current steps. At 925nm, quantum-well intermixing can be used to define non-absorbing mirrors giving good device reliability, albeit with a large efficiency penalty. Vacuum cleaved emitters have delivered excellent reliability at 915nm, and can be expected to perform just as well at 925 and 980nm. Epitaxial regrowth of laser facets is under development and has yet to demonstrate an appreciable reliability improvement. Only a weak correlation between start-of-life catastrophic optical mirror damage (COMD) levels and reliability was established. The optimized facet design has delivered maximum powers in excess of 19 MW/sq.cm (rollover limited) and product-grade 980nm single emitters with a slope efficiency of >1 W/A and a peak efficiency of >60%. The devices have accumulated over 1,500 hours of CW operation at 11W. A fiber-coupled device emits 10W ex-fiber with 47% efficiency.

  3. Design Considerations for High Temperature Power Inductors

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    2005-01-01

    A uniform B-field approximation model is used to develop design formulas for single-layer wound, toroidal core, ac power inductors that must handle a specified current. Such a geometry is well suited for high temperature, high frequency inductors, where removal of heat from the core becomes critical. Explicit expressions are derived for core radii, core and winding volumes, winding turns and core permeability as functions of a dimensional scaling ratio (S). A limit on the maximum allowed core B-field leads to the result that the minimum core volume is proportional to the permeability, which has a lower bound. Plots versus S are provided for a specific case, to show that good designs can be picked in the overlap regions around the minima in mass and overall size, where the mass and size are relatively flat. Data to 250 C are presented for an MPP core based inductor to show that a quasi-linear, high temperature inductor can be constructed with available materials. A similar development is applied to a toroidal air-core geometry, showing that for the same ratings, such an inductor is considerably bigger and more massive, at least in the single-layer version.

  4. High Power High Efficiency Ka-Band Power Combiners for Solid-State Devices

    NASA Technical Reports Server (NTRS)

    Freeman, Jon C.; Wintucky, Edwin G.; Chevalier, Christine T.

    2006-01-01

    Wide-band power combining units for Ka-band are simulated for use as MMIC amplifier applications. Short-slot couplers as well as magic-tees are the basic elements for the combiners. Wide bandwidth (5 GHz) and low insertion (approx.0.2 dB) and high combining efficiencies (approx.90 percent) are obtained.

  5. Compact, high-pulse-energy, high-power, picosecond master oscillator power amplifier.

    PubMed

    Chan, Ho-Yin; Alam, Shaif-Ul; Xu, Lin; Bateman, James; Richardson, David J; Shepherd, David P

    2014-09-08

    We report a compact, stable, gain-switched-diode-seeded master oscillator power amplifier (MOPA), employing direct amplification via conventional Yb(3+)-doped fibers, to generate picosecond pulses with energy of 17.7 μJ and 97-W average output power (excluding amplified spontaneous emission) at 5.47-MHz repetition frequency in a diffraction-limited and single-polarization beam. A maximum peak power of 197 kW is demonstrated. Such a high-energy, high-power, MHz, picosecond MOPA is of great interest for high-throughput material processing. With 13.8-μJ pulse energy confined in the 0.87-nm 3-dB spectral bandwidth, this MOPA is also a promising source for nonlinear frequency conversion to generate high-energy pulses in other spectral regions. We have explored the pulse energy scaling until the stimulated Raman Scattering (SRS) becomes significant (i.e. spectral peak intensity exceeds 1% of that of the signal).

  6. High Pulsed Power, Self Excited Magnetohydrodynamic Power Generation Systems

    DTIC Science & Technology

    1985-12-27

    Degree of Ionization of Cesium on Performance 72 3.5.7. Effect of Channel Area Ratio on Performance 73 3.5.8. Comparison of Helium vs Argon Generator...EXPLOSIVE PULSED SYSTEM WEIGHTS,REF.2 32 TABLE 5: POWER DENSITY & ENTHALPY EXTRACTION OF CLOSED CYCLE GENERATORS 35 TABLE 6: ENTHALPY EXTRACTION VS PRESSURE...OF ALUMINUM PARTICLES 50 TABLE 11. ALUMINUM PARTICLE BURNING TIMES vs OPERATING CONDITIONS 52 TABLE 12. TOTAL COMBUSTION TIME OF Al. PARTICLES vs

  7. Method and apparatus for improved high power impulse magnetron sputtering

    DOEpatents

    Anders, Andre

    2013-11-05

    A high power impulse magnetron sputtering apparatus and method using a vacuum chamber with a magnetron target and a substrate positioned in the vacuum chamber. A field coil being positioned between the magnetron target and substrate, and a pulsed power supply and/or a coil bias power supply connected to the field coil. The pulsed power supply connected to the field coil, and the pulsed power supply outputting power pulse widths of greater that 100 .mu.s.

  8. Neutron diffractometers for structural biology at spallation neutron sources

    SciTech Connect

    Schoenborn, B.P.; Pitcher, E.

    1994-12-31

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

  9. Ductile-to-brittle transition in spallation of metallic glasses

    SciTech Connect

    Huang, X.; Ling, Z.; Dai, L. H.

    2014-10-14

    In this paper, the spallation behavior of a binary metallic glass Cu{sub 50}Zr{sub 50} is investigated with molecular dynamics simulations. With increasing the impact velocity, micro-voids induced by tensile pulses become smaller and more concentrated. The phenomenon suggests a ductile-to-brittle transition during the spallation process. Further investigation indicates that the transition is controlled by the interaction between void nucleation and growth, which can be regarded as a competition between tension transformation zones (TTZs) and shear transformation zones (STZs) at atomic scale. As impact velocities become higher, the stress amplitude and temperature rise in the spall region increase and micro-structures of the material become more unstable. Therefore, TTZs are prone to activation in metallic glasses, leading to a brittle behavior during the spallation process.

  10. Characterization of the radiation background at the Spallation Neutron Source

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  11. Monte Carlo modeling of spallation targets containing uranium and americium

    NASA Astrophysics Data System (ADS)

    Malyshkin, Yury; Pshenichnov, Igor; Mishustin, Igor; Greiner, Walter

    2014-09-01

    Neutron production and transport in spallation targets made of uranium and americium are studied with a Geant4-based code MCADS (Monte Carlo model for Accelerator Driven Systems). A good agreement of MCADS results with experimental data on neutron- and proton-induced reactions on 241Am and 243Am nuclei allows to use this model for simulations with extended Am targets. It was demonstrated that MCADS model can be used for calculating the values of critical mass for 233,235U, 237Np, 239Pu and 241Am. Several geometry options and material compositions (U, U + Am, Am, Am2O3) are considered for spallation targets to be used in Accelerator Driven Systems. All considered options operate as deep subcritical targets having neutron multiplication factor of k∼0.5. It is found that more than 4 kg of Am can be burned in one spallation target during the first year of operation.

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

    NASA Astrophysics Data System (ADS)

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

    2010-07-01

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

  13. High power linear pulsed beam annealer

    DOEpatents

    Strathman, Michael D.; Sadana, Devendra K.; True, Richard B.

    1983-01-01

    A high power pulsed electron beam is produced in a system comprised of an electron gun having a heated cathode, control grid, focus ring, and a curved drift tube. The drift tube is maintained at a high positive voltage with respect to the cathode to accelerate electrons passing through the focus ring and to thereby eliminate space charge. A coil surrounding the curved drift tube provides a magnetic field which maintains the electron beam focused about the axis of the tube and imparts motion on electrons in a spiral path for shallow penetration of the electrons into a target. The curvature of the tube is selected so there is no line of sight between the cathode and a target holder positioned within a second drift tube spaced coaxially from the curved tube. The second tube and the target holder are maintained at a reference voltage that decelerates the electrons. A second coil surrounding the second drift tube maintains the electron beam focused about the axis of the second drift tube and compresses the electron beam to the area of the target. The target holder can be adjusted to position the target where the cross section of the beam matches the area of the target.

  14. Reactive high power impulse magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Gudmundsson, J. T.; Magnus, F.; Tryggvason, T. K.; Sveinsson, O. B.; Olafsson, S.

    2012-10-01

    Here we discuss reactive high power impulse magnetron sputtering sputtering (HiPIMS) [1] of Ti target in an Ar/N2 and Ar/O2 atmosphere. The discharge current waveform is highly dependent on both the pulse repetition frequency and discharge voltage. The discharge current increases with decreasing frequency or voltage. This we attribute to an increase in the secondary electron emission yield during the self-sputtering phase of the pulse, as nitride [2] or oxide [3] forms on the target. We also discuss the growth of TiN films on SiO2 at temperatures of 22-600 ^oC. The HiPIMS process produces denser films at lower growth temperature and the surface is much smoother and have a significantly lower resistivity than dc magnetron sputtered films on SiO2 at all growth temperatures due to reduced grain boundary scattering [4].[4pt] [1] J. T. Gudmundsson, N. Brenning, D. Lundin and U. Helmersson, J. Vac. Sci. Technol. A, 30 030801 (2012)[0pt] [2] F. Magnus, O. B. Sveinsson, S. Olafsson and J. T. Gudmundsson, J. Appl. Phys., 110 083306 (2011)[0pt] [3] F. Magnus, T. K. Tryggvason, S. Olafsson and J. T. Gudmundsson, J. Vac. Sci. Technol., submitted 2012[0pt] [4] F. Magnus, A. S. Ingason, S. Olafsson and J. T. Gudmundsson, IEEE Elec. Dev. Lett., accepted 2012

  15. Detection of supernova neutrinos at spallation neutron sources

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  16. Powerful Quasar Outflows at High Redshifts

    NASA Astrophysics Data System (ADS)

    Aljanahi, Sara; Robert Scott Barrows

    2017-01-01

    Powerful quasar outflows can be driven by radiation pressure or radio jets, and they are capable of effecting the evolution of their host galaxies, particularly at high-redshifts (z~2)) when the quasar density peaks. We present a multi-wavelength analysis of 131 quasar outflows at high-redshifts (0.8high-redshift nature of this sample has pushed the systematic study of quasar outflows closer to the epoch in which quasar feedback is likely to have been important in galaxy evolution.

  17. Complete low power controller for high voltage power systems

    SciTech Connect

    Sumner, R.; Blanar, G.

    1997-12-31

    The MHV100 is a custom CMOS integrated circuit, developed for the AMS experiment. It provides complete control for a single channel high voltage (HV) generator and integrates all the required digital communications, D to A and A to D converters, the analog feedback loop and output drivers. This chip has been designed for use in both distributed high voltage systems or for low cost single channel high voltage systems. The output voltage and current range is determined by the external components.

  18. The effects of shockwave profile shape and shock obliquity on spallation in Cu and Ta: kinetic and stress-state effects on damage evolution(u)

    SciTech Connect

    Gray, George T

    2010-12-14

    Widespread research over the past five decades has provided a wealth of experimental data and insight concerning shock hardening and the spallation response of materials subjected to square-topped shock-wave loading profiles. Less quantitative data have been gathered on the effect of direct, in-contact, high explosive (HE)-driven Taylor wave (or triangular-wave) loading profile shock loading on the shock hardening, damage evolution, or spallation response of materials. Explosive loading induces an impulse dubbed a 'Taylor Wave'. This is a significantly different loading history than that achieved by a square-topped impulse in terms of both the pulse duration at a fixed peak pressure, and a different unloading strain rate from the peak Hugoniot state achieved. The goal of this research is to quantify the influence of shockwave obliquity on the spallation response of copper and tantalum by subjecting plates of each material to HE-driven sweeping detonation-wave loading and quantify both the wave propagation and the post-mortem damage evolution. This talk will summarize our current understanding of damage evolution during sweeping detonation-wave spallation loading in Cu and Ta and show comparisons to modeling simulations. The spallation responses of Cu and Ta are both shown to be critically dependent on the shockwave profile and the stress-state of the shock. Based on variations in the specifics of the shock drive (pulse shape, peak stress, shock obliquity) and sample geometry in Cu and Ta, 'spall strength' varies by over a factor of two and the details of the mechanisms of the damage evolution is seen to vary. Simplistic models of spallation, such as P{sub min} based on 1-D square-top shock data lack the physics to capture the influence of kinetics on damage evolution such as that operative during sweeping detonation loading. Such considerations are important for the development of predictive models of damage evolution and spallation in metals and alloys.

  19. Concept of electric propulsion realization for high power space tug

    NASA Astrophysics Data System (ADS)

    Zakharenkov, L. E.; Semenkin, A. V.; Solodukhin, A. E.

    2016-07-01

    Popular at the beginning of the Space Age, ambitious projects aimed at Moon, Mars, and other space objects exploration, have returned with new technology and design level. High power space tug with electric propulsion system (EPS) is mainly considered as a transport vehicle for such missions. Modern high power space tugs projects as well as their spacecraft (SC) power and propulsion systems are reviewed in the paper. The main technologies and design solutions needed for high-power EPS realization are considered.

  20. The SPES High Power ISOL production target

    NASA Astrophysics Data System (ADS)

    Andrighetto, A.; Corradetti, S.; Ballan, M.; Borgna, F.; Manzolaro, M.; Scarpa, D.; Monetti, A.; Rossignoli, M.; Silingardi, R.; Mozzi, A.; Vivian, G.; Boratto, E.; De Ruvo, L.; Sattin, N.; Meneghetti, G.; Oboe, R.; Guerzoni, M.; Margotti, A.; Ferrari, M.; Zenoni, A.; Prete, G.

    2016-11-01

    SPES (Selective Production of Exotic Species) is a facility under construction at INFN-LNL (Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali di Legnaro), aimed to produce intense neutron-rich radioactive ion beams (RIBs). These will be obtained using the ISOL (Isotope Separation On-Line) method, bombarding a uranium carbide target with a proton beam of 40MeV energy and currents up to 200μA. The target configuration was designed to obtain a high number of fissions, up to 1013 per second, low power deposition and fast release of the produced isotopes. The exotic isotopes generated in the target are ionized, mass separated and re-accelerated by the ALPI superconducting LINAC at energies of 10AMeV and higher, for masses in the region of A = 130 amu , with an expected rate on the secondary target up to 109 particles per second. In this work, recent results on the R&D activities regarding the SPES RIB production target-ion source system are reported.

  1. Radiation of long and high power arcs

    NASA Astrophysics Data System (ADS)

    Cressault, Y.; Bauchire, J. M.; Hong, D.; Rabat, H.; Riquel, G.; Sanchez, F.; Gleizes, A.

    2015-10-01

    The operators working on electrical installations of low, medium and high voltages can be accidentally exposed to short-circuit arcs ranging from a few kA to several tens of kA. To protect them from radiation, according to the exposure limits, we need to characterize the radiation emitted by the powerful arc. Therefore, we have developed a general experimental and numerical study in order to estimate the spectral irradiance received at a given distance from the arc. The experimental part was based on a very long arc (up to 2 m) with high ac current (between 4 and 40 kA rms, duration 100 ms) using 3 kinds of metallic contacts (copper, steel and aluminium). We measured the irradiance received 10m from the axis of the arc, and integrated on 4 spectral intervals corresponding to the UV, visible, IRA  +  B and IRC. The theoretical part consisted of calculating the radiance of isothermal plasmas in mixtures of air and metal vapour, integrated over the same spectral intervals as defined in the experiments. The comparison between the theoretical and experimental results has allowed the defining of three isothermal radiation sources whose combination leads to a spectral irradiation equivalent to the experimental one. Then the calculation allowed the deduction of the spectral description of the irradiance over all the wavelength range, between 200 nm and 20 μm. The final results indicate that the influence of metal is important in the visible and UVA ranges whereas the IR radiation is due to the air plasma and surrounding hot gas and fumes.

  2. Waste heat recovery from the European Spallation Source cryogenic helium plants - implications for system design

    SciTech Connect

    Jurns, John M.; Bäck, Harald; Gierow, Martin

    2014-01-29

    The European Spallation Source (ESS) neutron spallation project currently being designed will be built outside of Lund, Sweden. The ESS design includes three helium cryoplants, providing cryogenic cooling for the proton accelerator superconducting cavities, the target neutron source, and for the ESS instrument suite. In total, the cryoplants consume approximately 7 MW of electrical power, and will produce approximately 36 kW of refrigeration at temperatures ranging from 2-16 K. Most of the power consumed by the cryoplants ends up as waste heat, which must be rejected. One hallmark of the ESS design is the goal to recycle waste heat from ESS to the city of Lund district heating system. The design of the cooling system must optimize the delivery of waste heat from ESS to the district heating system and also assure the efficient operation of ESS systems. This report outlines the cooling scheme for the ESS cryoplants, and examines the effect of the cooling system design on cryoplant design, availability and operation.

  3. RESULTS FROM CAVITATION DAMAGE EXPERIMENTS WITH MERCURY SPALLATION TARGETS AT THE LANSCE WNR IN 2008

    SciTech Connect

    Riemer, Bernie; Abdou, Ashraf A; Felde, David K; Sangrey, Robert L; Wendel, Mark W

    2010-01-01

    Damage assessment from proton beam induced cavitation experiments on mercury spallation targets done at the LANSCE WNR facility has been completed. The experiments investigated two key questions for the Spallation Neutron Source target, namely, how damage is affected by flow velocity in the SNS coolant channel geometry, and how damage scales with proton beam intensity at a given constant charge per pulse. With regard to the former question, prior in-beam experiments indicated that the coolant channel geometry with stagnant mercury was especially vulnerable to damage which might warrant a design change. Yet other results indicated a reduction in damage with the introduction of flow. Using more prototypic to the SNS, the 2008 experiment damage results show the channel is less vulnerable than the bulk mercury side of the vessel wall. They also show no benefit from increasing channel flow velocity beyond nominal SNS speeds. The second question probed a consensus belief that damage scales with beam intensity (protons per unit area) by a power law dependence with exponent of around 4. Results from a 2005 experiment did not support this power law dependence but some observations were inconsistent and unexplained. These latest results show weaker damage dependence.

  4. Laboratory Astrophysics on High Power Lasers and Pulsed Power Facilities

    SciTech Connect

    Remington, B A

    2002-02-05

    Over the past decade a new genre of laboratory astrophysics has emerged, made possible by the new high energy density (HED) experimental facilities, such as large lasers, z-pinch generators, and high current particle accelerators. (Remington, 1999; 2000; Drake, 1998; Takabe, 2001) On these facilities, macroscopic collections of matter can be created in astrophysically relevant conditions, and its collective properties measured. Examples of processes and issues that can be experimentally addressed include compressible hydrodynamic mixing, strong shock phenomena, radiative shocks, radiation flow, high Mach-number jets, complex opacities, photoionized plasmas, equations of state of highly compressed matter, and relativistic plasmas. These processes are relevant to a wide range of astrophysical phenomena, such as supernovae and supernova remnants, astrophysical jets, radiatively driven molecular clouds, accreting black holes, planetary interiors, and gamma-ray bursts. These phenomena will be discussed in the context of laboratory astrophysics experiments possible on existing and future HED facilities.

  5. 30 GHz High Power Production for CLIC

    SciTech Connect

    Syratchev, I.

    2006-01-03

    The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the impedance of the periodically loaded waveguide and excite preferentially the synchronous TM01 mode at 30 GHz. The RF power produced (several hundred MW) is collected at the downstream end of the structure by means of the Power Extractor and conveyed to the main linac structure. The PETS geometry is a result of multiple compromises between beam stability along single decelerator (600 m) and active length of the structure given by main linac RF power needs and layout. Surface electric and magnetic fields, power extraction method, HOM damping, ON/OFF capability and fabrication technology were all evaluated to provide reliable design.

  6. A 10-GeV, 5-MW proton source for a pulsed spallation source

    SciTech Connect

    Cho, Y.; Chae, Y.C.; Crosbie, E.

    1995-12-31

    A feasibility study for a pulsed spallation source based on a 5-MW, 10-GeV rapid proton synchrotron (RCS) is in progress. The integrated concept and performance parameters of the facility are discussed. The 10-GeV synchrotron uses as its injector the 2-GeV accelerator system of a 1-MW source described elsewhere. The 1-MW source accelerator system consists of a 400-MeV H{sup {minus}} linac with 2.5 MeV energy spread in the 75% chopped (25% removed) beam and a 30-Hz RCS that accelerates the 400-MeV beam to 2 GeV. The time averaged current of the accelerator system is 0.5 mA, equivalent to 1.04 {times} 10{sup 14} protons per pulse. The 10-GeV RCS accepts the 2 GeV beam and accelerates it to 10 GeV. Beam transfer from the 2-GeV synchrotron to the 10-GeV machine u highly efficient bunch-to-bucket injection, so that the transfer can be made without beam loss. The synchrotron lattice uses FODO cells of 90{degrees} phase advance. Dispersion-free straight sections are obtained using a missing magnet scheme. The synchrotron magnets are powered by dual-frequency resonant circuits. The magnets are excited at a 20-Hz rate and de-excited at 60-Hz. resulting in an effective 30-Hz rate. A key feature of the design of this accelerator system is that beam losses are minimized from injection to extraction, reducing activation to levels consistent with hands-on maintenance. Details of the study are presented.

  7. High-power converters for space applications

    NASA Technical Reports Server (NTRS)

    Park, J. N.; Cooper, Randy

    1991-01-01

    Phase 1 was a concept definition effort to extend space-type dc/dc converter technology to the megawatt level with a weight of less than 0.1 kg/kW (220 lb./MW). Two system designs were evaluated in Phase 1. Each design operates from a 5 kV stacked fuel cell source and provides a voltage step-up to 100 kV at 10 A for charging capacitors (100 pps at a duty cycle of 17 min on, 17 min off). Both designs use an MCT-based, full-bridge inverter, gaseous hydrogen cooling, and crowbar fault protection. The GE-CRD system uses an advanced high-voltage transformer/rectifier filter is series with a resonant tank circuit, driven by an inverter operating at 20 to 50 kHz. Output voltage is controlled through frequency and phase shift control. Fast transient response and stability is ensured via optimal control. Super-resonant operation employing MCTs provides the advantages of lossless snubbing, no turn-on switching loss, use of medium-speed diodes, and intrinsic current limiting under load-fault conditions. Estimated weight of the GE-CRD system is 88 kg (1.5 cu ft.). Efficiency of 94.4 percent and total system loss is 55.711 kW operating at 1 MW load power. The Maxwell system is based on a resonance transformer approach using a cascade of five LC resonant sections at 100 kHz. The 5 kV bus is converted to a square wave, stepped-up to a 100 kV sine wave by the LC sections, rectified, and filtered. Output voltage is controlled with a special series regulator circuit. Estimated weight of the Maxwell system is 83.8 kg (4.0 cu ft.). Efficiency is 87.2 percent and total system loss is 146.411 kW operating at 1 MW load power.

  8. Thermoelectric Powered High Temperature Wireless Sensing

    NASA Astrophysics Data System (ADS)

    Kucukkomurler, Ahmet

    This study describes use of a thermoelectric power converter to transform waste heat into electrical energy to power an RF receiver and transmitter, for use in harsh environment wireless temperature sensing and telemetry. The sensing and transmitting module employs a DS-1820 low power digital temperature sensor to perform temperature to voltage conversion, an ATX-34 RF transmitter, an ARX-34 RF receiver module, and a PIC16f84A microcontroller to synchronize data communication between them. The unit has been tested in a laboratory environment, and promising results have been obtained for an actual automotive wireless under hood temperature sensing and telemetry implementation.

  9. High-power microwaves for defense and accelerator applications

    SciTech Connect

    Manheimer, W. )

    1992-03-11

    This paper discusses high-power microwaves for application to the Defense Department and to the powering of large accelerators. The microwave sources discussed are the SLAC klystron, the relativistic klystron, the magnetron and the vircator.

  10. Opportunities for Neutrino Physics at the Spallation Neutron Source (SNS)

    SciTech Connect

    Efremenko, Yuri; Hix, William Raphael

    2009-01-01

    In this paper we discuss opportunities for a neutrino program at the Spallation Neutrons Source (SNS) being commissioning at ORNL. Possible investigations can include study of neutrino-nuclear cross sections in the energy rage important for supernova dynamics and neutrino nucleosynthesis, search for neutrino-nucleus coherent scattering, and various tests of the standard model of electro-weak interactions.

  11. Muon Induced Spallation Neutrons in the Sudbury Neutrino Observatory

    NASA Astrophysics Data System (ADS)

    Orrell, J. L.; Ahmad, Q. R.; Hazama, R.; Wilkerson, J. F.

    2001-05-01

    Neutrons produced as spallation products from muon passage through the Sudbury Neutrino Observatory (SNO) are studied. Muons can produce spallation neutrons through inelastic scattering on nuclei. Thermalized neutrons capture on the deuterium in SNO's heavy water detector volume via d(n,γ)t. The γ-ray has an energy of 6.25-MeV and produces a detectable signal in the SNO detector. We show it is possible to extract a nearly pure sample of thermalized neutrons. The observed capture time and energy are used to confirm the events' identity as neutrons. The total detection efficiency for muon induced spallation of neutrons is estimated and used to calculate the total muon induced spallation rate of neutrons in the SNO detector. This rate will impact the analysis of the Neutral Current Detectors (NCDs). The NCDs are ^3He proportional counters which will be inserted into SNO and used to measure the neutral current reaction of neutrinos, d(ν_x,n)p, in SNO's heavy water.

  12. Neutron science opportunities at pulsed spallation neutron sources

    SciTech Connect

    Carpenter, J.M.

    1996-12-31

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

  13. Gamma ray line production from cosmic ray spallation reactions

    NASA Technical Reports Server (NTRS)

    Silberberg, R.; Tsao, C. H.; Letaw, J. R.

    1985-01-01

    The gamma ray line intensities due to cosmic ray spallation reactions in clouds, the galactic disk and accreting binary pulsars are calculated. With the most favorable plausible assumptions, only a few lines may be detectable to the level of 0.0000001 per sq. cm per sec. The intensities are compared with those generated in nuclear excitation reactions.

  14. Overview of the Target Systems for the Spallation Neutron Source

    SciTech Connect

    Gabriel, T.A.; Haines, J.R.; McManamy, T.J.

    1998-10-15

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

  15. A High Power Frequency Doubled Fiber Laser

    NASA Technical Reports Server (NTRS)

    Thompson, Rob; Tu, Meirong; Aveline, Dave; Lundblad, Nathan; Maleki, Lute

    2003-01-01

    This slide presentation reviews the power frequencies for the doubled fiber laser. It includes information on the 780 nm laser, second harmonic generation in one crystal, cascading crystals, the tenability of laser systems, laser cooling, and directions for future work.

  16. HIGH POWER MICROWAVE FERRITES AND DEVICES

    DTIC Science & Technology

    FERROMAGNETIC MATERIALS, * MICROWAVE EQUIPMENT, ALUMINUM, DELAY LINES, ELECTRODES, FERRITES , GADOLINIUM , GARNET, IONS, IRON, MAGNESIUM ALLOYS...MAGNETIC FIELDS, MAGNETIC MATERIALS, MAGNETIC MOMENTS, MANGANESE ALLOYS, MICROWAVE SPECTROSCOPY, NICKEL ALLOYS, RADIOFREQUENCY POWER, RARE EARTH COMPOUNDS, SINGLE CRYSTALS, WAVEFORM GENERATORS, YTTRIUM.

  17. LIGHTWEIGHT HIGH-POWER THERMOELECTRIC MODULE DEVELOPMENT.

    DTIC Science & Technology

    ELECTRIC POWER PRODUCTION), *GENERATORS), (*THERMOCOUPLES, (*MODULES(ELECTRONICS), THERMOCOUPLES), (*THERMOELECTRICITY, HEAT, ENERGY CONVERSION, SEEBECK EFFECT , BONDED JOINTS, SILICON ALLOYS, GERMANIUM ALLOYS, LEAD ALLOYS, TELLURIUM ALLOYS, METALLOGRAPHY, SPACECRAFT COMPONENTS, MANUFACTURING.

  18. Modeling astatine production in liquid lead-bismuth spallation targets

    NASA Astrophysics Data System (ADS)

    David, J. C.; Boudard, A.; Cugnon, J.; Ghali, S.; Leray, S.; Mancusi, D.; Zanini, L.

    2013-03-01

    Astatine isotopes can be produced in liquid lead-bismuth eutectic targets through proton-induced double charge exchange reactions on bismuth or in secondary helium-induced interactions. Models implemented into the most common high-energy transport codes generally have difficulties to correctly estimate their production yields as was shown recently by the ISOLDE Collaboration, which measured release rates from a lead-bismuth target irradiated by 1.4 and 1 GeV protons. In this paper, we first study the capability of the new version of the Liège intranuclear cascade model, INCL4.6, coupled to the deexcitation code ABLA07 to predict the different elementary reactions involved in the production of such isotopes through a detailed comparison of the model with the available experimental data from the literature. Although a few remaining deficiencies are identified, very satisfactory results are found, thanks in particular to improvements brought recently on the treatment of low-energy helium-induced reactions. The implementation of the models into MCNPX allows identifying the respective contributions of the different possible reaction channels in the ISOLDE case. Finally, the full simulation of the ISOLDE experiment is performed, taking into account the likely rather long diffusion time from the target, and compared with the measured diffusion rates for the different astatine isotopes, at the two studied energies, 1.4 and 1 GeV. The shape of the isotopic distribution is perfectly reproduced as well as the absolute release rates, assuming in the calculation a diffusion time between 5 and 10hours. This work finally shows that our model, thanks to the attention paid to the emission of high-energy clusters and to low-energy cluster induced reactions, can be safely used within MCNPX to predict isotopes with a charge larger than that of the target by two units in spallation targets, and, probably, more generally to isotopes created in secondary reactions induced by composite

  19. Test Results From a High Power Linear Alternator Test Rig

    NASA Technical Reports Server (NTRS)

    Birchenough, Arthur G.; Hervol, David S.; Gardner, Brent G.

    2010-01-01

    Stirling cycle power conversion is an enabling technology that provides high thermodynamic efficiency but also presents unique challenges with regard to electrical power generation, management, and distribution. The High Power Linear Alternator Test Rig (HPLATR) located at the NASA Glenn Research Center (GRC) in Cleveland, Ohio is a demonstration test bed that simulates electrical power generation from a Stirling engine driven alternator. It implements the high power electronics necessary to provide a well regulated DC user load bus. These power electronics use a novel design solution that includes active rectification and power factor control, active ripple suppression, along with a unique building block approach that permits the use of high voltage or high current alternator designs. This report describes the HPLATR, the test program, and the operational results.

  20. Mechanical characterization of thin film structures using a laser spallation technique

    NASA Astrophysics Data System (ADS)

    Wu, Jianxin

    in using the microlithography technique to generate microcracks with controlled geometries between a thin film and its underlying substrate. The sample was mechanically loaded by using a laser generated stress pulse as discussed above. The crack propagation was monitored via a fast response circuit involving micro-wires on top of the cracked sample. The interface crack was observed to propagate at a speed close to the higher Rayleigh wave speed. Thus, all the necessary quantification techniques have been developed for the laser spallation technique. The application to the measurement of interface strength and dynamic fracture in thin film structures showed that this is a reliable, powerful, and unique technique that has opened up new fields for experimental and theoretical research.

  1. High-voltage, high-power, solid-state remote power controllers for aerospace applications

    NASA Technical Reports Server (NTRS)

    Sturman, J. C.

    1985-01-01

    Two general types of remote power controller (RPC) that combine the functions of a circuit breaker and a switch were developed for use in direct-current (dc) aerospace systems. Power-switching devices used in these designs are the relatively new gate-turnoff thyristor (GTO) and poweer metal-oxide-semiconductor field-effect transistors (MOSFET). The various RPC's can switch dc voltages to 1200 V and currents to 100 A. Seven different units were constructed and subjected to comprehensive laboratory and thermal vacuum testing. Two of these were dual units that switch both positive and negative voltages simultaneously. The RPC's using MOSFET's have slow turnon and turnoff times to limit voltage spiking from high di/dt. The GTO's have much faster transition times. All RPC's have programmable overload tripout and microsecond tripout for large overloads. The basic circuits developed can be used to build switchgear limited only by the ratings of the switching device used.

  2. High Efficiency Microwave Power Amplifier: From the Lab to Industry

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III; Bell, Joseph L. (Technical Monitor)

    2001-01-01

    Since the beginnings of space travel, various microwave power amplifier designs have been employed. These included Class-A, -B, and -C bias arrangements. However, shared limitation of these topologies is the inherent high total consumption of input power associated with the generation of radio frequency (RF)/microwave power. The power amplifier has always been the largest drain for the limited available power on the spacecraft. Typically, the conversion efficiency of a microwave power amplifier is 10 to 20%. For a typical microwave power amplifier of 20 watts, input DC power of at least 100 watts is required. Such a large demand for input power suggests that a better method of RF/microwave power generation is required. The price paid for using a linear amplifier where high linearity is unnecessary includes higher initial and operating costs, lower DC-to-RF conversion efficiency, high power consumption, higher power dissipation and the accompanying need for higher capacity heat removal means, and an amplifier that is more prone to parasitic oscillation. The first use of a higher efficiency mode of power generation was described by Baxandall in 1959. This higher efficiency mode, Class-D, is achieved through distinct switching techniques to reduce the power losses associated with switching, conduction, and gate drive losses of a given transistor.

  3. Scaling brilliance of high power laser diodes

    NASA Astrophysics Data System (ADS)

    König, Harald; Grönninger, Guenther; Lauer, Christian; Reill, Wolfgang; Arzberger, Markus; Strauß, Uwe; Kissel, Heiko; Biesenbach, Jens; Kösters, Arnd; Malchus, Joerg; Krause, Volker K.

    2010-02-01

    New direct diode laser systems and fiber lasers require brilliant fiber coupled laser diodes for efficient operation. In the German funded project HEMILAS different laser bar designs are investigated with tailored beam parameter products adapted for efficient fiber coupling. In this paper we demonstrate results on 9xx and 1020nm bars suitable for coupling into 200μm fibers. With special facet technology and optimised epitaxial structure COD-free laser bars were fabricated with maximum efficiency above 66%. For short bars consisting of five 100μm wide emitters 75W CW maximum output power was reached. In QCW-mode up to 140W are demonstrated. The 10% fill factor bars with 4mm cavity are mounted with hard solder. Lifetime tests in long pulse mode with 35W output power exceed 5000 hours of testing without degradation or spontaneous failures. Slow axis divergence stays below 7° up to power levels of 40W and is suitable for simple fiber coupling into 200μm NA 0.22 fibers with SAC and FAC lenses. For fiber coupling based on beam rearrangement with step mirrors, bars with higher fill factor of 50% were fabricated and tested. The 4mm cavity short bars reach efficiencies above 60%. Lifetime tests at accelerated powers were performed. Finally fiber coupling results with output powers of up to 2.4 kW and beam quality of 30 mm mrad are demonstrated.

  4. 157 W all-fiber high-power picosecond laser.

    PubMed

    Song, Rui; Hou, Jing; Chen, Shengping; Yang, Weiqiang; Lu, Qisheng

    2012-05-01

    An all-fiber high-power picosecond laser is constructed in a master oscillator power amplifier configuration. The self-constructed fiber laser seed is passively mode locked by a semiconductor saturable absorber mirror. Average output power of 157 W is obtained after three stages of amplification at a fundamental repetition rate of 60 MHz. A short length of ytterbium double-clad fiber with a high doping level is used to suppress nonlinear effects. However, a stimulated Raman scattering (SRS) effect occurs owing to the 78 kW high peak power. A self-made all-fiber repetition rate increasing system is used to octuple the repetition rate and decrease the high peak power. Average output power of 156.6 W is obtained without SRS under the same pump power at a 480 MHz repetition rate with 0.6 nm line width.

  5. Measurement of interface strength by a laser spallation technique

    NASA Astrophysics Data System (ADS)

    Gupta, V.; Argon, A. S.; Parks, D. M.; Cornie, J. A.

    A LASER spallation experiment has been developed to measure the strength of planar interfaces between a substrate and a thin coating (in the thickness range of 0.3-3 μm). In this technique a laser pulse of a high enough energy and a pre-determined duration is converted into a pressure pulse of a critical amplitude and width that is sent through the substrate toward the free surface with the coating. The reflected tensile wave from the free surface of the coating pries-off the coating. The critical stress amplitude that accomplishes the removal of the coating is determined from a computer simulation of the process. The simulation itself is verified by means of a piezo-electric crystal probe that is capable of mapping out the profile of the stress pulse generated by the laser pulse. Interface strength values ranging from 3.7 to 10.5 GPa were determined for the Si/SiC system. For the interfaces between pyrolytic graphite and SiC coatings an average strength of 7.2 GPA was measured, while the corresponding interface strength between a Pitch-55 type ribbon with a fiber-like morphology and SiC coatings was found to be 0.23 GPa. Intrinsic strengths of SiC coatings and Si crystal were also determined using this technique. These were, on the average, 8.6 GPa for Si crystals and 11.9 GPa for a SiC coating. Furthermore, the potential of the laser technique to determine the interface toughness was also demonstrated, provided well-characterizable flaws can be planted on the interface.

  6. The COHERENT Experiment at the Spallation Neutron Source

    SciTech Connect

    Elliott, Steven Ray

    2015-09-30

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

  7. Atmospheric Propagation and Combining of High-Power Lasers

    DTIC Science & Technology

    2015-09-08

    Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6703--15-9646 Atmospheric Propagation and Combining of High - Power Lasers W. NelsoN...ABSTRACT c. THIS PAGE 18. NUMBER OF PAGES 17. LIMITATION OF ABSTRACT Atmospheric Propagation and Combining of High - Power Lasers W. Nelson,* P. Sprangle...Turbulence Beam combining In this paper we analyze the beam combining and atmospheric propagation of high - power lasers for directed-energy (DE

  8. High Temperature Power Converters for Military Hybrid Electric Vehicles

    DTIC Science & Technology

    2011-08-09

    M) MINI-SYMPOSIUM AUGUST 9-11 DEARBORN, MICHIGAN HIGH TEMPERATURE POWER CONVERTERS FOR MILITARY HYBRID ELECTRIC VEHICLES ABSTRACT...SUBTITLE High Temperature Power Converters for Military Hybrid Electric Vehicles 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...public release High Temperature Power Converters for Military Hybrid Electric Vehicles Page 2 of 8 I. INTRODUCTION Today, wide bandgap devices

  9. Gallium Nitride (GaN) High Power Electronics (FY11)

    DTIC Science & Technology

    2012-01-01

    Gallium Nitride (GaN) High Power Electronics (FY11) by Kenneth A. Jones, Randy P. Tompkins, Michael A. Derenge, Kevin W. Kirchner, Iskander...Army Research Laboratory Adelphi, MD 20783-1197 ARL-TR-5903 January 2012 Gallium Nitride (GaN) High Power Electronics (FY11) Kenneth A...DSI 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Gallium Nitride (GaN) High Power Electronics (FY11) 5a. CONTRACT NUMBER 5b. GRANT

  10. Power affects performance when the pressure is on: evidence for low-power threat and high-power lift.

    PubMed

    Kang, Sonia K; Galinsky, Adam D; Kray, Laura J; Shirako, Aiwa

    2015-05-01

    The current research examines how power affects performance in pressure-filled contexts. We present low-power-threat and high-power-lift effects, whereby performance in high-stakes situations suffers or is enhanced depending on one's power; that is, the power inherent to a situational role can produce effects similar to stereotype threat and lift. Three negotiations experiments demonstrate that role-based power affects outcomes but only when the negotiation is diagnostic of ability and, therefore, pressure-filled. We link these outcomes conceptually to threat and lift effects by showing that (a) role power affects performance more strongly when the negotiation is diagnostic of ability and (b) underperformance disappears when the low-power negotiator has an opportunity to self-affirm. These results suggest that stereotype threat and lift effects may represent a more general phenomenon: When the stakes are raised high, relative power can act as either a toxic brew (stereotype/low-power threat) or a beneficial elixir (stereotype/high-power lift) for performance.

  11. Effects of surface deposition, hole blockage, and thermal barrier coating spallation on vane endwall film cooling

    SciTech Connect

    Sundaram, N.; Thole, K.A.

    2007-07-15

    With the increase in usage of gas turbines for power generation and given that natural gas resources continue to be depleted, it has become increasingly important to search for alternate fuels. One source of alternate fuels is coal derived synthetic fuels. Coal derived fuels, however, contain traces of ash and other contaminants that can deposit on vane and turbine surfaces affecting their heat transfer through reduced film cooling. The endwall of a first stage vane is one such region that can be susceptible to depositions from these contaminants. This study uses a large-scale turbine vane cascade in which the following effects on film cooling adiabatic effectiveness were investigated in the endwall region: the effect of near-hole deposition, the effect of partial film cooling hole blockage, and the effect of spallation of a thermal barrier coating. The results indicated that deposits near the hole exit can sometimes improve the cooling effectiveness at the leading edge, but with increased deposition heights the cooling deteriorates. Partial hole blockage studies revealed that the cooling effectiveness deteriorates with increases in the number of blocked holes. Spallation studies showed that for a spalled endwall surface downstream of the leading edge cooling row, cooling effectiveness worsened with an increase in blowing ratio.

  12. Radio Sounding Science at High Powers

    NASA Technical Reports Server (NTRS)

    Green, J. L.; Reinisch, B. W.; Song, P.; Fung, S. F.; Benson, R. F.; Taylor, W. W. L.; Cooper, J. F.; Garcia, L.; Markus, T.; Gallagher, D. L.

    2004-01-01

    Future space missions like the Jupiter Icy Moons Orbiter (JIMO) planned to orbit Callisto, Ganymede, and Europa can fully utilize a variable power radio sounder instrument. Radio sounding at 1 kHz to 10 MHz at medium power levels (10 W to kW) will provide long-range magnetospheric sounding (several Jovian radii) like those first pioneered by the radio plasma imager instrument on IMAGE at low power (less than l0 W) and much shorter distances (less than 5 R(sub E)). A radio sounder orbiting a Jovian icy moon would be able to globally measure time-variable electron densities in the moon ionosphere and the local magnetospheric environment. Near-spacecraft resonance and guided echoes respectively allow measurements of local field magnitude and local field line geometry, perturbed both by direct magnetospheric interactions and by induced components from subsurface oceans. JIMO would allow radio sounding transmissions at much higher powers (approx. 10 kW) making subsurface sounding of the Jovian icy moons possible at frequencies above the ionosphere peak plasma frequency. Subsurface variations in dielectric properties, can be probed for detection of dense and solid-liquid phase boundaries associated with oceans and related structures in overlying ice crusts.

  13. Simulation of High Power Lasers (Preprint)

    DTIC Science & Technology

    2010-06-01

    product of laser power. 5. References 1 Wilcox, D. C, Turbulence Modeling for CFD, DCW Industries, Inc. pp. 185-193, July 1998. 2 Menter, F. L...Modeling for CFD, DCW Industries, Inc. pp. 294-296, July 1998. 4 Perram, G. P, .Int. J. Chem. Kinet. 27, 817-28 (1995). 5 Madden, T. J. and Solomon

  14. High power transportable VLF transmitter facility

    NASA Astrophysics Data System (ADS)

    Dazey, M. H.; Koons, H. C.

    1982-05-01

    A 100-kW, transportable, very-low-frequency (TVLF) transmitter facility has been used for magnetospheric wave-injection experiments from sites in Alaska, New Zealand and Norway. A unique feature of the TVLF facility is the antenna which is a conducting cable lofted to an altitude of 1000 m by a 1000 cu m3 helium balloon. The antenna is driven at its base as a monopole above a ground plane. The antenna cable also serves as the balloon tether. The lowest operating frequency in this configuration is 6.6 kHz at which the radiated power is 100 W. At the highest operating frequency used in the experiments, 21 kHz, the radiated power is 10 kW. In Norway power lines were used as antennas. The minimum operating frequency was then 1 kHz and the radiated power is estimated to be about 0.5 W. In this report we describe the components and performance of the TVLF as used for these magnetospheric experiments.

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

    SciTech Connect

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

    2002-12-30

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

  16. Preparation and testing of corrosion and spallation-resistant coatings

    SciTech Connect

    Hurley, John P.; Cavalli, Matthew N.

    2016-06-30

    The goal of this project was to take a recently developed method of bonding oxide dispersion-strengthened (ODS) FeCrAl plating to nickel superalloys closer to commercial use in syngas-fired turbines. The project was designed to better understand and develop the bonding process and to determine if plating APMT®, a specific highly oxidation-resistant ODS FeCrAl alloy made by Kanthal, onto nickel-based superalloy turbine parts is a viable method for substantially improving the lifetimes and maximum use temperatures of the parts. The superalloys investigated for protection were CM247LC and Rene® 80, both alumina scale-forming alloys. The method for bonding the APMT plate to the superalloys is called evaporative metal bonding, which involves placing a thin foil of zinc between the plate and the superalloy, clamping them together, and heating in an atmosphere-controlled furnace. Upon heating, the zinc melts and dissolves the oxide skins of the alloys at the bond line, allowing the two alloys to diffuse into each other. The zinc then diffuses through the alloys and evaporates from their surfaces, creating a bond between the APMT and the superalloy that is stronger than the APMT itself. Testing showed that the diffusivity of zinc in both APMT and CM247LC is quite similar at 700°C but 15 times higher in the APMT at 1214°C. Coefficients of thermal expansion were determined for each of the alloys as a function of temperature. This information was entered into a finite-element model using ANSYS, which was used to design a clamping jig for pressing the APMT to the superalloys at the bonding temperature. Scanning electron microscopy analyses of representative joints showed that no zinc remained in the alloys after bonding Unfortunately, the analyses also showed some small pieces of broken aluminum oxide scale near the bond lines, indicating that its scale was not sufficiently removed during prebonding cleaning. Samples from each of the bonded blocks were sent to Siemens for

  17. Optimized concept design of the target station of Chinese spallation neutron source

    NASA Astrophysics Data System (ADS)

    Yan, Q. W.; Yin, W.; Yu, B. L.

    2005-08-01

    CSNS (Chinese spallation neutron source) target station, with proton beam power of 100 kW, consists of Tungsten rectangular target surrounded by a beryllium/steel reflector, three wing-moderators and the shield having 18 beam tubes. The leakage neutron intensity from the target (with reflector) and heat deposition on the target, reflector and shield were calculated using Monte Carlo code NMTC/JAM respectively. It is reported that the target having rectangular section will produce more leakage neutron intensity than a square one for the same proton power. The temperature and thermal stress distribution in the target disks were calculated by the finite element method. The performances of moderators were calculated using MCNP-4A code.

  18. High Performance Power Module for Hall Effect Thrusters

    NASA Technical Reports Server (NTRS)

    Pinero, Luis R.; Peterson, Peter Y.; Bowers, Glen E.

    2002-01-01

    Previous efforts to develop power electronics for Hall thruster systems have targeted the 1 to 5 kW power range and an output voltage of approximately 300 V. New Hall thrusters are being developed for higher power, higher specific impulse, and multi-mode operation. These thrusters require up to 50 kW of power and a discharge voltage in excess of 600 V. Modular power supplies can process more power with higher efficiency at the expense of complexity. A 1 kW discharge power module was designed, built and integrated with a Hall thruster. The breadboard module has a power conversion efficiency in excess of 96 percent and weighs only 0.765 kg. This module will be used to develop a kW, multi-kW, and high voltage power processors.

  19. Design and Construction of Low Cost High Voltage dc Power Supply for Constant Power Operation

    NASA Astrophysics Data System (ADS)

    Kumar, N. S.; Jayasankar, V.

    2013-06-01

    Pulsed load applications like laser based systems need high voltage dc power supplies with better regulation characteristics. This paper presents the design, construction and testing of dc power supply with 1 kV output at 300 W power level. The designed converter has half bridge switched mode power supply (SMPS) configuration with 20 kHz switching. The paper covers the design of half bridge inverter, closed loop control, High frequency transformer and other related electronics. The designed power supply incorporates a low cost OPAMP based feedback controller which is designed using small signal modelling of the converter. The designed converter was constructed and found to work satisfactorily as per the specifications.

  20. High power gas laser - Applications and future developments

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.

    1977-01-01

    Fast flow can be used to create the population inversion required for lasing action, or can be used to improve laser operation, for example by the removal of waste heat. It is pointed out that at the present time all lasers which are capable of continuous high-average power employ flow as an indispensable aspect of operation. High power laser systems are discussed, taking into account the gasdynamic laser, the HF supersonic diffusion laser, and electric discharge lasers. Aerodynamics and high power lasers are considered, giving attention to flow effects in high-power gas lasers, aerodynamic windows and beam manipulation, and the Venus machine. Applications of high-power laser technology reported are related to laser material working, the employment of the laser in controlled fusion machines, laser isotope separation and photochemistry, and laser power transmission.

  1. Review of high-power microwave source research

    NASA Astrophysics Data System (ADS)

    Gold, Steven H.; Nusinovich, Gregory S.

    1997-11-01

    This article reviews the state-of-the-art in high-power microwave source research. It begins with a discussion of the concepts involved in coherent microwave generation. The main varieties of microwave tubes are classified into three groups, according to the fundamental radiation mechanism involved: Cherenkov, transition, or bremsstrahlung radiation. This is followed by a brief discussion of some of the technical fundamentals of high-power microwave sources, including power supplies and electron guns. Finally, the history and recent developments of both high-peak power and high-average power sources are reviewed in the context of four main areas of application: (1) plasma resonance heating and current drive; (2) rf acceleration of charged particles; (3) radar and communications systems; and (4) high-peak power sources for weapons-effect simulation and exploratory development.

  2. Lifetest on a high-power laser diode array transmitter

    NASA Astrophysics Data System (ADS)

    Greulich, P.; Hespeler, B.; Spatscheck, Th.

    1991-05-01

    The optical transmiter component of a free space optical communication system is critical, in that it impacts on the mechanical configuration, power requirements, mass, reliability, and transmission bit-rate of the entire system. Attention is presently given to the transmitter output power and beam quality, as well as its electrical-to-optical power conversion efficiency, in view of state-of-the-art high power transmitters for intensity modulation/direct detection and semiconductor laser transmitter systems.

  3. High Efficiency Thermoelectric Radioisotope Power Systems

    NASA Technical Reports Server (NTRS)

    El-Genk, Mohamed; Saber, Hamed; Caillat, Thierry

    2004-01-01

    The work performed and whose results presented in this report is a joint effort between the University of New Mexico s Institute for Space and Nuclear Power Studies (ISNPS) and the Jet Propulsion Laboratory (JPL), California Institute of Technology. In addition to the development, design, and fabrication of skutterudites and skutterudites-based segmented unicouples this effort included conducting performance tests of these unicouples for hundreds of hours to verify theoretical predictions of the conversion efficiency. The performance predictions of these unicouples are obtained using 1-D and 3-D models developed for that purpose and for estimating the actual performance and side heat losses in the tests conducted at ISNPS. In addition to the performance tests, the development of the 1-D and 3-D models and the development of Advanced Radioisotope Power systems for Beginning-Of-Life (BOM) power of 108 We are carried out at ISNPS. The materials synthesis and fabrication of the unicouples are carried out at JPL. The research conducted at ISNPS is documented in chapters 2-5 and that conducted at JP, in documented in chapter 5. An important consideration in the design and optimization of segmented thermoelectric unicouples (STUs) is determining the relative lengths, cross-section areas, and the interfacial temperatures of the segments of the different materials in the n- and p-legs. These variables are determined using a genetic algorithm (GA) in conjunction with one-dimensional analytical model of STUs that is developed in chapter 2. Results indicated that when optimized for maximum conversion efficiency, the interfacial temperatures between various segments in a STU are close to those at the intersections of the Figure-Of-Merit (FOM), ZT, curves of the thermoelectric materials of the adjacent segments. When optimizing the STUs for maximum electrical power density, however, the interfacial temperatures are different from those at the intersections of the ZT curves, but

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

  5. E-beam high voltage switching power supply

    DOEpatents

    Shimer, D.W.; Lange, A.C.

    1996-10-15

    A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 figs.

  6. E-beam high voltage switching power supply

    DOEpatents

    Shimer, Daniel W.; Lange, Arnold C.

    1996-01-01

    A high-power power supply produces a controllable, constant high voltage put under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

  7. High-power microwave attenuator employing slow wave structure

    NASA Astrophysics Data System (ADS)

    Yoshida, Mitsuhiro; Matsumoto, Hiroshi; Shintake, Tsumoru; Nishiyama, Koji; Miura, Sadao

    2012-11-01

    Using present pulsed microwave amplifier, we can obtain RF peak power beyond one hundred MW. However, it is not easy to test such a high-power RF. To overcome this difficulty we developed a high-power microwave attenuator employing a slow wave structure. For example, the output power of RF pulse compressor for present electron linear accelerator reaches a few hundreds MW RF power, but the existing dummy loads can absorb only a few tens MW of RF power. The attenuator we developed has a kind of periodic structure and is made of metal only. We operated this attenuator using a high-power RF source, and found that it could be operated fewer than 50 pps RF output at 40 MW, 2.5 μs or 100 MW, 0.5 μs.

  8. High-power hydrogen arcjet performance

    NASA Technical Reports Server (NTRS)

    Haag, Thomas W.; Curran, Francis M.

    1991-01-01

    A hydrogen arcjet was operated at power levels ranging from 5 to 30 kW with three different nozzle geometries. Test results using all three nozzle geometries are reported and include variations of specific impulse with flow rate, and thrust with power. Geometric variables investigated included constrictor diameter, length, and diverging exit angle. The nozzle with a constrictor diameter of 1.78 mm and divergence angle of 20 deg was found to give the highest performance. A specific impulse of 1460 s was attained with this nozzle at a thrust efficiency of 29.8 percent. The best efficiency measured was 34.4 percent at a specific impulse of 1045 s. Post test examination of the cathode showed erosion after 28 hours of operation to be small, and limited to the conical tip where steady state arc attachment occurred. Each nozzle was tested to destruction.

  9. High-power hydrogen arcjet performance

    NASA Technical Reports Server (NTRS)

    Haag, Thomas W.; Curran, Francis M.

    1991-01-01

    A hydrogen arcjet was operated at power levels ranging from 5 to 30 kW with three different nozzle geometries. Test results using all three nozzle geometries are reported and include variations of specific impulse with flow rate, and thrust with power. Geometric variables investigated included constrictor diameter, length, and diverging exit angle. The nozzle with a constrictor diameter of 1.78 mm and divergence angle of 20 degrees was found to give the highest performance. A specific impulse of 1460 s was attained with this nozzle at a thrust efficiency of 29.8 percent. The best efficiency measured was 34.4 percent at a specific impulse of 1045 s. Post test examination of the cathode showed erosion after 28 hours of operation to be small, and limited to the conical tip where steady state arc attachment occurred. Each nozzle was tested to destruction.

  10. Plasma-Based Tunable High Frequency Power Limiter

    NASA Astrophysics Data System (ADS)

    Semnani, Abbas; Macheret, Sergey; Peroulis, Dimitrios

    2016-09-01

    Power limiters are often employed to protect sensitive receivers from being damaged or saturated by high-power incoming waves. Although wideband low-power limiters based on semiconductor technology are widely available, the options for high-power frequency-selective ones are very few. In this work, we study the application of a gas discharge tube (GDT) integrated in an evanescent-mode (EVA) cavity resonator as a plasma-based power limiter. Plasmas can inherently handle higher power in comparison with semiconductor diodes. Also, using a resonant structure provides the ability of having both lower threshold power and frequency-selective limiting, which are important if only a narrowband high-power signal is targeted. Higher input RF power results in stronger discharge in the GDT and consequently higher electron density which results in larger reflection. It is also possible to tune the threshold power by pre-ionizing the GDT with a DC bias voltage. As a proof of concept, a 2-GHz EVA resonator loaded by a 90-V GDT was fabricated and measured. With reasonable amount of insertion loss, the limiting threshold power was successfully tuned from 8.3 W to 590 mW when the external DC bias was varied from 0 to 80 V. The limiter performed well up to 100 W of maximum available input power.

  11. High Power Co-Axial Coupler

    SciTech Connect

    Johnson, Rolland; Neubauer, Michael

    2013-08-14

    A superconducting RF (SRF) power coupler capable of handling 500 kW CW RF power at 750 MHz is required for present and future storage rings and linacs. There are over 35 coupler designs for SRF cavities ranging in frequency from 325 to 1500 MHz. Coupler windows vary from cylinders to cones to disks and RF power couplers will always be limited by the ability of ceramic windows and their matching systems to withstand the stresses due to non-uniform heating from dielectric and wall losses, multipactor, and mechanical flexure. In the Phase II project, we built a double window coaxial system with materials that would not otherwise be useable due to individual VSWRs. Double window systems can be operated such that one is cold (LN2) and one is warm. They can have different materials and still have a good match without using matching elements that create problematic multipactor bands. The match of the two windows will always result from the cancellation of the two window’s reflections when they are located approximately a quarter wavelength apart or multiples of a quarter wavelength. The window assemblies were carefully constructed to put the window material and its braze joint in compression at all times. This was done using explosion bonding techniques which allow for inexpensive fabrication of the vacuum / compression ring out of stainless steel with copper plating applied to the inner surface. The EIA 3-1/8” double window assembly was then successfully baked out and tested to 12 kW in a 3-1/8” co-axial system. The thermal gradient across the window was measured to be 90 C which represents about 15 ksi tensile stress in an uncompressed window. In our design the compression was calculated to be about 25 ksi, so the net compressive force was 5 ksi at full power.

  12. High-power MUTC photodetectors for RF photonic links

    NASA Astrophysics Data System (ADS)

    Estrella, Steven; Johansson, Leif A.; Mashanovitch, Milan L.; Beling, Andreas

    2016-02-01

    High power photodiodes are needed for a range of applications. The high available power conversion efficiency makes these ideal for antenna remoting applications, including high power, low duty-cycle RF pulse generation. The compact footprint and fiber optic input allow densely packed RF aperture arrays with low cross-talk for phased high directionality emitters. Other applications include linear RF photonic links and other high dynamic range optical systems. Freedom Photonics has developed packaged modified uni-traveling carrier (MUTC) photodetectors for high-power applications. Both single and balanced photodetector pairs are mounted on a ceramic carrier, and packaged in a compact module optimized for high power operation. Representative results include greater than 100 mA photocurrent, >100m W generated RF power and >20 GHz bandwidth. In this paper, we evaluate the saturation and bandwidth of these single ended and balanced photodetectors for detector diameter in the 16 μm to 34 μm range. Packaged performance is compared to chip performance. Further new development towards the realization of <100GHz packaged photodetector modules with optimized high power performance is described. Finally, incorporation of these photodetector structures in novel photonic integrated circuits (PICs) for high optical power application areas is outlined.

  13. High Input Voltage, Silicon Carbide Power Processing Unit Performance Demonstration

    NASA Technical Reports Server (NTRS)

    Bozak, Karin E.; Pinero, Luis R.; Scheidegger, Robert J.; Aulisio, Michael V.; Gonzalez, Marcelo C.; Birchenough, Arthur G.

    2015-01-01

    A silicon carbide brassboard power processing unit has been developed by the NASA Glenn Research Center in Cleveland, Ohio. The power processing unit operates from two sources - a nominal 300-Volt high voltage input bus and a nominal 28-Volt low voltage input bus. The design of the power processing unit includes four low voltage, low power supplies that provide power to the thruster auxiliary supplies, and two parallel 7.5 kilowatt power supplies that are capable of providing up to 15 kilowatts of total power at 300-Volts to 500-Volts to the thruster discharge supply. Additionally, the unit contains a housekeeping supply, high voltage input filter, low voltage input filter, and master control board, such that the complete brassboard unit is capable of operating a 12.5 kilowatt Hall Effect Thruster. The performance of unit was characterized under both ambient and thermal vacuum test conditions, and the results demonstrate the exceptional performance with full power efficiencies exceeding 97. With a space-qualified silicon carbide or similar high voltage, high efficiency power device, this design could evolve into a flight design for future missions that require high power electric propulsion systems.

  14. High-power semiconductor lasers at eye-safe wavelengths

    NASA Astrophysics Data System (ADS)

    Osowski, Mark L.; Gewirtz, Yossi; Lammert, Robert M.; Oh, Se W.; Panja, Chameli; Elarde, Victor C.; Vaissie, Laurent; Patel, Falgun D.; Ungar, Jeffrey E.

    2009-05-01

    InP based diode lasers are required to realize the next generation of eyesafe applications, including direct rangefinding and HEL weapons systems. We report on the progress of high power eyesafe single spatial and longitudinal mode 1550nm MOPA devices, where we have achieved peak powers in excess of 10W with 50ns pulse widths. A conceptual model based on our recent MOPA results show the path towards scaling to high powers based on spatial beam combination with operating conditions suitable for direct rangefinding applications. We also report on the progress towards high power 14xx and 15xx nm pump lasers for eyesafe HEL systems.

  15. Assessment of the neutron cross section database for mercury for the ORNL spallation source

    SciTech Connect

    Leal, L.C.; Spencer, R.R.; Ingersoll, D.T.; Gabriel, T.A.

    1996-06-01

    Neutron source generation based on a high energy particle accelerator has been considered as an alternative to the canceled Advanced Neutron Source project at Oak Ridge National Laboratory. The proposed technique consists of a spallation neutron source in which neutrons are produced via the interaction of high-energy charged particles in a heavy metal target. Preliminary studies indicate that liquid mercury bombarded with GeV protons provides an excellent neutron source. Accordingly, a survey has been made of the available neutron cross-section data. Since it is expected that spectral modifiers, specifically moderators, will also be incorporated into the source design, the survey included thermal energy, resonance region, and high energy data. It was found that data of individual isotopes were almost non-existent and that the only evaluation found for the natural element had regions of missing data or discrepant data. Therefore, it appears that to achieve the desired degree of accuracy in the spallation source design it is necessary to re-evaluate the mercury database including making new measurements. During the presentation the currently available data will be presented and experiments proposed which can lead to design quality cross sections.

  16. High average power diamond Raman laser.

    PubMed

    Feve, Jean-Philippe M; Shortoff, Kevin E; Bohn, Matthew J; Brasseur, Jason K

    2011-01-17

    We report a pulsed Raman laser at 1193 nm based on synthetic diamond crystals with a record output power of 24.5 W and a slope efficiency of 57%. We compared the performance of an anti-reflection coated crystal at normal incidence with a Brewster cut sample. Raman oscillation was achieved at both room temperature and under cryogenic operation at 77 K. Modeling of these experiments allowed us to confirm the value of Raman gain coefficient of diamond, which was found to be 13.5 ± 2.0 cm/GW for a pump wavelength of 1030 nm.

  17. Wireless power transfer and fault diagnosis of high-voltage power line via robotic bird

    NASA Astrophysics Data System (ADS)

    Liu, Chunhua; Chau, K. T.; Zhang, Zhen; Qiu, Chun; Li, Wenlong; Ching, T. W.

    2015-05-01

    This paper presents a new idea of wireless power transfer (WPT) and fault diagnosis (FD) of high-voltage power line via robotic bird. The key is to present the conceptual robotic bird with WPT coupling coil for detecting and capturing the energy from the high-voltage power line. If the power line works in normal condition, the robotic bird is able to stand on the power line and extract energy from it. If fault occurs on the power line, the corresponding magnetic field distribution will become different from that in the normal situation. By analyzing the magnetic field distribution of the power line, the WPT to the robotic bird and the FD by the robotic bird are performed and verified.

  18. High density operation for reactor-relevant power exhaust

    NASA Astrophysics Data System (ADS)

    Wischmeier, M.

    2015-08-01

    With increasing size of a tokamak device and associated fusion power gain an increasing power flux density towards the divertor needs to be handled. A solution for handling this power flux is crucial for a safe and economic operation. Using purely geometric arguments in an ITER-like divertor this power flux can be reduced by approximately a factor 100. Based on a conservative extrapolation of current technology for an integrated engineering approach to remove power deposited on plasma facing components a further reduction of the power flux density via volumetric processes in the plasma by up to a factor of 50 is required. Our current ability to interpret existing power exhaust scenarios using numerical transport codes is analyzed and an operational scenario as a potential solution for ITER like divertors under high density and highly radiating reactor-relevant conditions is presented. Alternative concepts for risk mitigation as well as strategies for moving forward are outlined.

  19. Pulse wireless photonic power transfer at high irradiance

    NASA Astrophysics Data System (ADS)

    Dhadwal, Harbans S.; Rastegar, Jahangir; Kwok, Philip

    2014-06-01

    Photonic power conversion combined with a high power laser diode, is a high efficiency solution for rapid, wireless transfer of power to dormant sensors, which have sporadic need for electrical power. In particular, these devices replace, thermal/inductive power sources inside a munition shell, leading to a safe non-radiating environment. Experimental results with a 25 F double-layer, super-capacitor, indicate that the surface irradiance and laser power both determine the minimum energy transfer time. At a power level of 4 W, the energy transfer rate reduces from a 1 J/s to 0.35 J/s as the irradiance level changes from 1125 suns to 63 suns.

  20. Atmospheric propagation and combining of high power lasers: comment.

    PubMed

    Goodno, Gregory D; Rothenberg, Joshua E

    2016-10-10

    Nelson et al. [Appl. Opt.55, 1757 (2016)APOPAI0003-693510.1364/AO.55.001757] recently concluded that coherent beam combining and remote phase locking of high-power lasers are fundamentally limited by the laser source linewidth. These conclusions are incorrect and not relevant to practical high-power coherently combined laser architectures.

  1. From the electromagnetic pulse to high-power electromagnetics

    NASA Astrophysics Data System (ADS)

    Baum, Carl E.

    1992-06-01

    This paper updates the published literature of the late 1970's concerning the development of requisite technology for the nuclear EMP. EMP has impacted a set of related areas that can be collectively referred to as high-power electromagnetics. This includes high-power microwaves, direct-strike lightning, and some aspects of transient radar.

  2. Novel Polymers for High Efficiency Renewable and Portable Power Applications

    DTIC Science & Technology

    2015-07-30

    force between the polymer and dye would result in weaker PL quenching and optoelectronic device power conversion efficiency, this experimentally...model. The results could be very useful for materials design for developing high efficiency organic and polymer based optoelectronic devices; 2) Optimum...Apr-2015 Approved for Public Release; Distribution Unlimited Final Report: Novel Polymers for High Efficiency Renewable and Portable Power

  3. DEVELOPMENT OF HIGH-POWER BROADBAND TUBES AND RELATED STUDIES

    DTIC Science & Technology

    Performance characteristics of a centipede high-power TWT are presented. The design of components for the 10 Mw cloverleaf TWT is described and a...be made relatively easily and cheaply. Performance characteristics of a centipede high-power TWT are presented. The design of components for the 10

  4. 3-D Printed High Power Microwave Magnetrons

    NASA Astrophysics Data System (ADS)

    Jordan, Nicholas; Greening, Geoffrey; Exelby, Steven; Gilgenbach, Ronald; Lau, Y. Y.; Hoff, Brad

    2015-11-01

    The size, weight, and power requirements of HPM systems are critical constraints on their viability, and can potentially be improved through the use of additive manufacturing techniques, which are rapidly increasing in capability and affordability. Recent experiments on the UM Recirculating Planar Magnetron (RPM), have explored the use of 3-D printed components in a HPM system. The system was driven by MELBA-C, a Marx-Abramyan system which delivers a -300 kV voltage pulse for 0.3-1.0 us, with a 0.15-0.3 T axial magnetic field applied by a pair of electromagnets. Anode blocks were printed from Water Shed XC 11122 photopolymer using a stereolithography process, and prepared with either a spray-coated or electroplated finish. Both manufacturing processes were compared against baseline data for a machined aluminum anode, noting any differences in power output, oscillation frequency, and mode stability. Evolution and durability of the 3-D printed structures were noted both visually and by tracking vacuum inventories via a residual gas analyzer. Research supported by AFOSR (grant #FA9550-15-1-0097) and AFRL.

  5. Low reflectance high power RF load

    DOEpatents

    Ives, R. Lawrence; Mizuhara, Yosuke M.

    2016-02-02

    A load for traveling microwave energy has an absorptive volume defined by cylindrical body enclosed by a first end cap and a second end cap. The first end cap has an aperture for the passage of an input waveguide with a rotating part that is coupled to a reflective mirror. The inner surfaces of the absorptive volume consist of a resistive material or are coated with a coating which absorbs a fraction of incident RF energy, and the remainder of the RF energy reflects. The angle of the reflector and end caps is selected such that reflected RF energy dissipates an increasing percentage of the remaining RF energy at each reflection, and the reflected RF energy which returns to the rotating mirror is directed to the back surface of the rotating reflector, and is not coupled to the input waveguide. Additionally, the reflector may have a surface which generates a more uniform power distribution function axially and laterally, to increase the power handling capability of the RF load. The input waveguide may be corrugated for HE11 mode input energy.

  6. Studies of basic mechanisms in high pressure gases: Applications to high efficiency high power lasers

    NASA Technical Reports Server (NTRS)

    Verdeyen, J. T.; Cherrington, B. E.; Leslie, S. G.; Millar, W. S.; Edwards, B. E.

    1976-01-01

    A high power pulsed dye laser was used to optically excite high pressure cesium-xenon mixtures and the resulting measurements are presented. A microwave discharge in rubidium at relatively high xenon pressure was achieved. Preliminary studies of cadium-rare gas mixtures are discussed and a detailed description of the entire experimental apparatus is given.

  7. LATIS modeling of laser induced midplane and backplane spallation

    SciTech Connect

    Glinksky, M.E.; Bailey, D.S.; London, R.A.

    1997-03-05

    The computer code LATIS is used to simulate midplane and backplane spallation resulting from short pulsed laser absorption. A 1-D planar geometry is simulated with an exponential laser absorption profile. The laser pulse length is assumed to be much shorter than the sound transit time across the laser absorption length. The boundary conditions are a fixed front plane and free backplane (backplane spall) and a free front plane and a fixed midplane (midplane spall). The NBS/NRC equation of state for water is used with a self- consistent yet empirical material strength and failure model. The failure model includes the effects of void nucleation, growth and coalescence. Definite signatures of the nucleation and coalescence thresholds are found in the back surface motion for backplane spallation.

  8. Development of high coherence high power 193nm laser

    NASA Astrophysics Data System (ADS)

    Tanaka, Satoshi; Arakawa, Masaki; Fuchimukai, Atsushi; Sasaki, Yoichi; Onose, Takashi; Kamba, Yasuhiro; Igarashi, Hironori; Qu, Chen; Tamiya, Mitsuru; Oizumi, Hiroaki; Ito, Shinji; Kakizaki, Koji; Xuan, Hongwen; Zhao, Zhigang; Kobayashi, Yohei; Mizoguchi, Hakaru

    2016-03-01

    We have been developing a hybrid 193 nm ArF laser system that consists of a solid state seeding laser and an ArF excimer laser amplifier for power-boosting. The solid state laser consists of an Yb-fiber-solid hybrid laser system and an Er-fiber laser system as fundamentals, and one LBO and three CLBO crystals for frequency conversion. In an ArF power amplifier, the seed laser passes through the ArF gain media three times, and an average power of 110 W is obtained. As a demonstration of the potential applications of the laser, an interference exposure test is performed.

  9. Low power, high voltage power supply with fast rise/fall time

    NASA Technical Reports Server (NTRS)

    Bearden, Douglas B. (Inventor)

    2007-01-01

    A low power, high voltage power supply system includes a high voltage power supply stage and a preregulator for programming the power supply stage so as to produce an output voltage which is a predetermined fraction of a desired voltage level. The power supply stage includes a high voltage, voltage doubler stage connected to receive the output voltage from the preregulator and for, when activated, providing amplification of the output voltage to the desired voltage level. A first feedback loop is connected between the output of the preregulator and an input of the preregulator while a second feedback loop is connected between the output of the power supply stage and the input of the preregulator.

  10. Low Power, High Voltage Power Supply with Fast Rise/Fall Time

    NASA Technical Reports Server (NTRS)

    Bearden, Douglas B. (Inventor)

    2007-01-01

    A low power, high voltage power supply system includes a high voltage power supply stage and a preregulator for programming the power supply stage so as to produce an output voltage which is a predetermined fraction of a desired voltage level. The power supply stage includes a high voltage, voltage doubler stage connected to receive the output voltage from the preregulator and for, when activated, providing amplification of the output voltage to the desired voltage level. A first feedback loop is connected between the output of the preregulator and an input of the preregulator while a second feedback loop is connected between the output of the power supply stage and the input of the preregulator.

  11. Titanium-Alloy Power Capacitor: High-Power Titanate Capacitor for Power Electronics

    SciTech Connect

    2010-09-01

    ADEPT Project: There is a constant demand for better performing, more compact, lighter weight, and lower cost electronic devices. Unfortunately, the materials traditionally used to make components for electronic devices have reached their limits. Case Western is developing capacitors made of new materials that could be used to produce the next generation of compact and efficient high-powered consumer electronics and electronic vehicles. A capacitor is an important component of an electronic device. It stores an electric charge and then discharges it into an electrical circuit in the device. Case Western is creating its capacitors from titanium, an abundant material extracted from ore which can be found in the U.S. Case Western's capacitors store electric charges on the surfaces of films, which are grown on a titanium alloy electrode that is formed as a spinal column with attached branches. The new material and spine design make the capacitor smaller and lighter than traditional capacitors, and they enable the component to store 300% more energy than capacitors of the same weight made of tantalum, the current industry standard. Case Western's titanium-alloy capacitors also spontaneously self-repair, which prolongs their life.

  12. High efficiency fuel cell/advanced turbine power cycles

    SciTech Connect

    Morehead, H.

    1995-10-19

    An outline of the Westinghouse high-efficiency fuel cell/advanced turbine power cycle is presented. The following topics are discussed: The Westinghouse SOFC pilot manufacturing facility, cell scale-up plan, pressure effects on SOFC power and efficiency, sureCell versus conventional gas turbine plants, sureCell product line for distributed power applications, 20 MW pressurized-SOFC/gas turbine power plant, 10 MW SOFC/CT power plant, sureCell plant concept design requirements, and Westinghouse SOFC market entry.

  13. Cascade: a high-efficiency ICF power reactor

    SciTech Connect

    Pitts, J.H.

    1985-10-31

    Cascade attains a net power-plant efficiency of 49% and its cost is competitive with high-temperature gas-cooled reactor, pressurized-water reactor, and coal-fired power plants. The Cascade reactor and blanket are made of ceramic materials and activation is 6 times less than that of the MARS Tandem Mirror Reactor operating at comparable power. Hands-on maintenance of the heat exchangers is possible one day after shutdown. Essentially all tritium is recovered in the vacuum system, with the remainder recovered from the helium power conversion loop. Tritium leakage external to the vacuum system and power conversion loop is only 0.03 Ci/d.

  14. Decommissioning and PIE of the MEGAPIE spallation target

    SciTech Connect

    Latge, C.; Henry, J.; Wohlmuther, M.; Dai, Y.; Gavillet, D.; Hammer, B.; Heinitz, S.; Neuhausen, J.; Schumann, D.; Thomsen, K.; Tuerler, A.; Wagner, W.; Gessi, A.; Guertin, A.; Konstantinovic, M.; Lindau, R.; Maloy, S.; Saito, S.

    2013-07-01

    A key experiment in the Accelerated Driven Systems roadmap, the MEGAwatt PIlot Experiment (MEGAPIE) (1 MW) was initiated in 1999 in order to design and build a liquid lead-bismuth spallation target, then to operate it into the Swiss spallation neutron facility SINQ at Paul Scherrer Institute. The target has been designed, manufactured, and tested during integral tests, before irradiation carried out end of 2006. During irradiation, neutron and thermo hydraulic measurements were performed allowing deep interpretation of the experiment and validation of the models used during design phase. The decommissioning, Post Irradiation Examinations and waste management phases were defined properly. The phases dedicated to cutting, sampling, cleaning, waste management, samples preparation and shipping to various laboratories were performed by PSI teams: all these phases constitute a huge work, which allows now to perform post-irradiation examination (PIE) of structural material, irradiated in relevant conditions. Preliminary results are presented in the paper, they concern chemical characterization. The following radio-nuclides have been identified by γ-spectrometry: {sup 60}Co, {sup 101}Rh, {sup 102}Rh, {sup 108m}Ag, {sup 110m}Ag, {sup 133}Ba, {sup 172}Hf/Lu, {sup 173}Lu, {sup 194}Hg/Au, {sup 195}Au, {sup 207}Bi. For some of these nuclides the activities can be easily evaluated from γ-spectrometry results ({sup 207}Bi, {sup 194}Hg/Au), while other nuclides can only be determined after chemical separations ({sup 108m}Ag, {sup 110m}Ag, {sup 195}Au, {sup 129}I, {sup 36}Cl and α-emitting {sup 208-210}Po). The concentration of {sup 129}I is lower than expected. The chemical analysis already performed on spallation and corrosion products in the lead-bismuth eutectic (LBE) are very relevant for further applications of LBE as a spallation media and more generally as a coolant.

  15. The BLAIRR Irradiation Facility Hybrid Spallation Target Optimization

    SciTech Connect

    Simos N.; Hanson A.; Brown, D.; Elbakhshawn, M.

    2016-04-11

    BLAIRR STUDY STATUS OVERVIEW Beamline Complex Evaluation/Assessment and Adaptation to the Goals Facility Radiological Constraints ? Large scale analyses of conventional facility and integrated shield (concrete, soil)Target Optimization and Design: Beam-target interaction optimization Hadronic interaction and energy deposition limitations Single phase and Hybrid target concepts Irradiation Damage Thermo-mechanical considerations Spallation neutron fluence optimization for (a) fast neutron irradiation damage (b) moderator/reflector studies, (c) NTOF potential and optimization (d) mono-energetic neutron beam

  16. Moisture-Induced Alumina Scale Spallation: The Hydrogen Factor

    NASA Technical Reports Server (NTRS)

    Smialek, James L.

    2010-01-01

    For some time the oxidation community has been concerned with interfacial spallation of protective alumina scales, not just upon immediate cool down, but as a time-delayed phenomenon. Moisture-induced delayed spallation (MIDS) and desktop spallation (DTS) of thermal barrier coatings (TBCs) refer to this process. It is most apparent for relatively adherent alumina scales that have survived initial cool down in a dry environment, have built up considerable thickness and strain energy, and have been somewhat damaged, such as by cyclic oxidation cracking. Indeed, a "sensitive zone" can be described that maximizes the observed effect as a function of all the relevant factors. Moisture has been postulated to serve as a source of interfacial hydrogen embrittlement. Hydrogen is derived from reaction with aluminum in the alloy at an exposed interface. The purpose of this monograph is to trace the close analogy of this phenomenon to other hydrogen-induced effects, such as embrittlement of aluminides and blistering of alloys and anodic alumina films. A formalized, top-down, logic-tree structure is presented as a guide to this discussion. A theoretical basis for interfacial weakening by hydrogen is first cited, as are demonstrations of hydrogen detection as a reaction product or interfacial species. Further support is provided by critical experiments that recreate the moisture effect, but by isolating hydrogen from other potential causative factors. These experiments include tests in H 2-containing atmospheres or cathodic hydrogen charging. Accordingly, they strongly indicate that interfacial hydrogen, derived from moisture, is the key chemical species accounting for delayed alumina scale spallation.

  17. Titanium spallation cross sections between 30 and 584 MeV and Ar-39 activities on the moon

    NASA Technical Reports Server (NTRS)

    Steinburnn, F.; Fireman, E. L.

    1974-01-01

    The production cross sections of Ar39 for Ti spallation at 45-, 319-, 433-, and 584-MeV proton energies were measured to be 0.37 + or - 0.09, 12.4 + or - 3.7, 9.1 + or - 2.7, and 17.8 + or - 6.2 mb, respectively. Normalized Ar39 production rates and activities are also derived for protons above 40 MeV and for three differential proton spectra of the type approximately E(- alpha). It is concluded that, even for samples of high-Ti content, Ti spallation by solar protons below 200-MeV energy does not contribute significantly to their Ar39 radioactivity.

  18. High Input Voltage, Silicon Carbide Power Processing Unit Performance Demonstration

    NASA Technical Reports Server (NTRS)

    Bozak, Karin E.; Pinero, Luis R.; Scheidegger, Robert J.; Aulisio, Michael V.; Gonzalez, Marcelo C.; Birchenough, Arthur G.

    2015-01-01

    A silicon carbide brassboard power processing unit has been developed by the NASA Glenn Research Center in Cleveland, Ohio. The power processing unit operates from two sources: a nominal 300 Volt high voltage input bus and a nominal 28 Volt low voltage input bus. The design of the power processing unit includes four low voltage, low power auxiliary supplies, and two parallel 7.5 kilowatt (kW) discharge power supplies that are capable of providing up to 15 kilowatts of total power at 300 to 500 Volts (V) to the thruster. Additionally, the unit contains a housekeeping supply, high voltage input filter, low voltage input filter, and master control board, such that the complete brassboard unit is capable of operating a 12.5 kilowatt Hall effect thruster. The performance of the unit was characterized under both ambient and thermal vacuum test conditions, and the results demonstrate exceptional performance with full power efficiencies exceeding 97%. The unit was also tested with a 12.5kW Hall effect thruster to verify compatibility and output filter specifications. With space-qualified silicon carbide or similar high voltage, high efficiency power devices, this would provide a design solution to address the need for high power electric propulsion systems.

  19. Coupled Ablation, Heat Conduction, Pyrolysis, Shape Change and Spallation of the Galileo Probe

    NASA Technical Reports Server (NTRS)

    Milos, Frank S.; Chen, Y.-K.; Rasky, Daniel J. (Technical Monitor)

    1995-01-01

    The Galileo probe enters the atmosphere of Jupiter in December 1995. This paper presents numerical methodology and detailed results of our final pre-impact calculations for the heat shield response. The calculations are performed using a highly modified version of a viscous shock layer code with massive radiation coupled with a surface thermochemical ablation and spallation model and with the transient in-depth thermal response of the charring and ablating heat shield. The flowfield is quasi-steady along the trajectory, but the heat shield thermal response is dynamic. Each surface node of the VSL grid is coupled with a one-dimensional thermal response calculation. The thermal solver includes heat conduction, pyrolysis, and grid movement owing to surface recession. Initial conditions for the heat shield temperature and density were obtained from the high altitude rarefied-flow calculations of Haas and Milos. Galileo probe surface temperature, shape, mass flux, and element flux are all determined as functions of time along the trajectory with spallation varied parametrically. The calculations also estimate the in-depth density and temperature profiles for the heat shield. All this information is required to determine the time-dependent vehicle mass and drag coefficient which are necessary inputs for the atmospheric reconstruction experiment on board the probe.

  20. High-Power-Density Organic Radical Batteries.

    PubMed

    Friebe, Christian; Schubert, Ulrich S

    2017-02-01

    Batteries that are based on organic radical compounds possess superior charging times and discharging power capability in comparison to established electrochemical energy-storage technologies. They do not rely on metals and, hence, feature a favorable environmental impact. They furthermore offer the possibility of roll-to-roll processing through the use of different printing techniques, which enables the cost-efficient fabrication of mechanically flexible devices. In this review, organic radical batteries are presented with the focus on the hitherto developed materials and the key properties thereof, e.g., voltage, capacity, and cycle life. Furthermore, basic information, such as significant characteristics, housing approaches, and applied additives, are presented and discussed in the context of organic radical batteries.