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Sample records for accelerator laboratory slac

  1. Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory

    SciTech Connect

    Weathersby, S. P.; Brown, G.; Centurion, M.; Chase, T. F.; Coffee, R.; Corbett, J.; Eichner, J. P.; Frisch, J. C.; Fry, A. R.; Gühr, M.; Hartmann, N.; Hast, C.; Hettel, R.; Jobe, R. K.; Jongewaard, E. N.; Lewandowski, J. R.; Li, R. K.; Lindenberg, A. M.; Makasyuk, I.; May, J. E.; McCormick, D.; Nguyen, M. N.; Reid, A. H.; Shen, X.; Sokolowski-Tinten, K.; Vecchione, T.; Vetter, S. L.; Wu, J.; Yang, J.; Dürr, H. A.; Wang, X. J.

    2015-07-01

    Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

  2. Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory.

    PubMed

    Weathersby, S P; Brown, G; Centurion, M; Chase, T F; Coffee, R; Corbett, J; Eichner, J P; Frisch, J C; Fry, A R; Gühr, M; Hartmann, N; Hast, C; Hettel, R; Jobe, R K; Jongewaard, E N; Lewandowski, J R; Li, R K; Lindenberg, A M; Makasyuk, I; May, J E; McCormick, D; Nguyen, M N; Reid, A H; Shen, X; Sokolowski-Tinten, K; Vecchione, T; Vetter, S L; Wu, J; Yang, J; Dürr, H A; Wang, X J

    2015-07-01

    Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability. PMID:26233391

  3. Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory

    SciTech Connect

    Weathersby, S. P.; Brown, G.; Chase, T. F.; Coffee, R.; Corbett, J.; Eichner, J. P.; Frisch, J. C.; Fry, A. R.; Gühr, M.; Hartmann, N.; Hast, C.; Hettel, R.; Jobe, R. K.; Jongewaard, E. N.; Lewandowski, J. R.; Li, R. K. Lindenberg, A. M.; Makasyuk, I.; May, J. E.; McCormick, D.; and others

    2015-07-15

    Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

  4. Advocacy for the Archives and History Office of the SLAC National Accelerator Laboratory: Stages and Methods

    SciTech Connect

    Deken, Jean Marie; /SLAC

    2009-06-19

    Advocating for the good of the SLAC Archives and History Office (AHO) has not been a one-time affair, nor has it been a one-method procedure. It has required taking time to ascertain the current and perhaps predict the future climate of the Laboratory, and it has required developing and implementing a portfolio of approaches to the goal of building a stronger archive program by strengthening and appropriately expanding its resources. Among the successful tools in the AHO advocacy portfolio, the Archives Program Review Committee has been the most visible. The Committee and the role it serves as well as other formal and informal advocacy efforts are the focus of this case study My remarks today will begin with a brief introduction to advocacy and outreach as I understand them, and with a description of the Archives and History Office's efforts to understand and work within the corporate culture of the SLAC National Accelerator Laboratory. I will then share with you some of the tools we have employed to advocate for the Archives and History Office programs and activities; and finally, I will talk about how well - or badly - those tools have served us over the past decade.

  5. SLAC accelerator operations report: 1992-1995

    SciTech Connect

    Erickson, R.; Allen, C.W.; Inman, T.K.; Linebarger, W.; Stanek, M.

    1995-05-01

    Operational statistics for the linear accelerator programs at SLAC are presented, including run-time records for the SLC, FFTB, and fixed target programs. Also included are summaries of reliability and maintenance-related statistics and a discussion of the analysis tools used to study error messages generated by the control system.

  6. A New Control Room for SLAC Accelerators

    SciTech Connect

    Erickson, Roger; Guerra, E.; Stanek, M.; Hoover, Z.Van; Warren, J.; /SLAC

    2012-06-04

    We are planning to construct a new control room at SLAC to unify and improve the operation of the LCLS, SPEAR3, and FACET accelerator facilities, and to provide the space and flexibility needed to support the LCLS-II and proposed new test beam facilities. The existing control rooms for the linac and SPEAR3 have been upgraded in various ways over the last decade, but their basic features have remained unchanged. We propose to build a larger modern Accelerator Control Room (ACR) in the new Research Support Building (RSB) which is currently under construction at SLAC. Shifting the center of control for the accelerator facilities entails both technical and administrative challenges. In this paper, we describe the history, concept, and status of this project.

  7. Radiation Protection in the NLC Test Accelerator at SLAC

    NASA Astrophysics Data System (ADS)

    Lavine, Theodore L.; Vylet, Vaclav

    1997-05-01

    This paper describes the elements of the design of the NLC Test Accelerator pertaining to ionizing radiation protection and safety. The NLC Test Accelerator is an accelerator physics research facility at SLAC designed to validate 2.6-cm microwave linear accelerator technology for a future high-energy linear collider (the "Next Linear Collider"). The NLC Test Accelerator is designed for average beam power levels up to 1.5 kW, at energies up to 1 GeV (roughly equivalent to 1/500 of an NLC linac). The design for radiation protection incorporates shielding, configuration controls, safety interlock systems for personnel protection and beam containment, and operations procedures. The design was guided by the DOE Accelerator Safety Order, internal Laboratory policy, and the general principle of keeping radiation doses as low as reasonably achievable.

  8. R&D of Accelerator Structures at SLAC

    SciTech Connect

    Wang, J.W.; /SLAC

    2007-01-17

    The research activities for accelerator structures at SLAC are reviewed including the achievement via the main linac design for the Next Linear Collider (NLC), the program adjustment after the decision of the International Linear Collider (ILC) to be based on superconducting technology, and the work progress for the ILC, photon science at SLAC and basic accelerator structure studies.

  9. Accelerator physics: Surf's up at SLAC

    NASA Astrophysics Data System (ADS)

    Downer, Mike; Zgadzaj, Rafal

    2014-11-01

    A 'plasma afterburner' just 30 centimetres long accelerates electrons hundreds of times faster than giant conventional accelerators. The result may ultimately open up a low-cost technology for particle colliders. See Letter p.92

  10. SLAC site design aesthetics

    SciTech Connect

    Hall, F.F.

    1985-10-01

    Stanford Linear Accelerator Center (SLAC) is a single mission laboratory dedicated to basic research in high energy particle physics. SLAC site also houses Stanford Synchrotron Radiation Laboratory (SSRL) which is a multi-mission laboratory for research using beams of ultraviolet light and low energy photons as emitted tangentially from SLAC colliding beam facilities. This paper discusses various aspects of SLAC site design aesthetics under the following headings: (1) imposed footprint of SLAC, (2) description of selected site, (3) use of earth cover for radiation and sight screens, (4) use of landscaping for cosmetic purposes, (5) use of exterior paint colors to soften SLAC impact on neighbors, (6) relocation of SLAC main entrance, (7) relocation of SLAC collider arcs and experimental hall, (8) parking lots and storage yards, and (9) land use zoning at SLAC.

  11. ORION: An Advanced Accelerator Facility at SLAC

    SciTech Connect

    Palmer, Dennis

    2002-08-20

    Extending the center-of-mass energy frontier for high-energy physics depends on the research and development that is conducted now in the area of advanced accelerator physics and technology. In this article, we present the design and beam dynamics simulations for the emittance-compensated, RF photoinjector of the ORION Facility.

  12. SLC status and SLAC (Stanford Linear Accelerator Center) future plans

    SciTech Connect

    Richter, B.

    1989-08-01

    In this presentation, I shall discuss the linear collider program at the Stanford Linear Accelerator Center as it is now, and as we hope to see it evolve over the next few years. Of greatest interest to the high energy accelerator physics community gathered here is the development of the linear collider concept, and so I shall concentrate most of this paper on a discussion of the present status and future evolution of the SLC. I will also briefly discuss the research and development program that we are carrying out aimed at the realization of the next generation of high-energy linear colliders. SLAC had a major colliding-beam storage-ring program as well, including present rings and design studies on future high-luminosity projects, but time constraints preclude a discussion of them. 8 figs., 3 tabs.

  13. Acceleration of high charge density electron beams in the SLAC linac

    SciTech Connect

    Sheppard, J.C.; Clendenin, J.E.; Jobe, R.K.; Lueth, V.G.; Millich, A.; Ross, M.C.; Seeman, J.T.; Stiening, R.F.

    1984-01-01

    The SLAC Linear Collider (SLC) will require both electron and positron beams of very high charge density and low emittance to be accelerated to about 50 GeV in the SLAC 3-km linac. The linac is in the process of being improved to meet this requirement. The program to accelerate an electron beam of high charge density through the first third of the SLC linac is described and the experimental results are discussed. 7 references, 5 figures.

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

    SciTech Connect

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

    2007-04-09

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

  15. Summary of SLAC's SEY Measurement On Flat Accelerator Wall Materials

    SciTech Connect

    Le Pimpec, F.; /PSI, Villigen /SLAC

    2007-06-08

    The electron cloud effect (ECE) causes beam instabilities in accelerator structures with intense positively charged bunched beams. Reduction of the secondary electron yield (SEY) of the beam pipe inner wall is effective in controlling cloud formation. We summarize SEY results obtained from flat TiN, TiZrV and Al surfaces carried out in a laboratory environment. SEY was measured after thermal conditioning, as well as after low energy, less than 300 eV, particle exposure.

  16. Using The SLAC Two-Mile Accelerator for Powering an FEL

    SciTech Connect

    Barletta, W.A.; Sessler, A.M.; Yu, L.H.; /Brookhaven

    2012-06-29

    A parameter survey is made, employing the recently developed 2D formalism for an FEL, of the characteristics of an FEL using the SLAC accelerator. Attention is focused upon a wavelength of 40 {angstrom} (the water window) and 1 {angstrom} case is also presented. They consider employing the SLAC linac with its present operating parameters and with improved parameters such as would be supplied by a new photo-cathode injector. They find that improved parameters are necessary, but that the parameters presently achieved with present-day photo-cathode guns are adequate to reach the water window.

  17. High Frequency, High Gradient Dielectric Wakefield Acceleration Experiments at SLAC and BNL

    NASA Astrophysics Data System (ADS)

    Rosenzweig, J. B.; Andonian, G.; Muggli, P.; Niknejadi, P.; Travish, G.; Williams, O.; Xuan, K.; Yakimenko, V.

    2010-11-01

    Given the recent success of >GV/m dielectric wakefield accelerator (DWA) breakdown experiments at SLAC, and follow-on coherent Cerenkov radiation (CCR) production at the UCLA Neptune, a UCLA-USC-SLAC collaboration is now implementing a new set of experiments that explore various DWA scenarios. These experiments are motivated by the opportunities presented by the approval of the FACET facility at SLAC, as well as unique pulse-train wakefield drivers at BNL. The SLAC experiments permit further exploration of the multi-GeV/m envelope in DWAs, and will entail investigations of novel materials (e.g. CVD diamond) and geometries (Bragg cylindrical structures, slab-symmetric DWAs), and have an over-riding goal of demonstrating >GeV acceleration in ˜33 cm DWA tubes. In the nearer term before FACET's commissioning, we are performing measurements at the BNL ATF, in which we drive ˜50-200 MV/m fields with single pulses or pulse trains, and observe resonantly driven CCR as well as deflection modes. These experiments are of high relevance to enhancing linear collider DWA designs, as they will demonstrate potential for high efficiency operation with pulse trains, and explore transverse modes for the first time.

  18. High Frequency, High Gradient Dielectric Wakefield Acceleration Experiments at SLAC and BNL

    SciTech Connect

    Rosenzweig, J. B.; Andonian, G.; Niknejadi, P.; Travish, G.; Williams, O.; Xuan, K.; Muggli, P.; Yakimenko, V.

    2010-11-04

    Given the recent success of >GV/m dielectric wakefield accelerator (DWA) breakdown experiments at SLAC, and follow-on coherent Cerenkov radiation (CCR) production at the UCLA Neptune, a UCLA-USC-SLAC collaboration is now implementing a new set of experiments that explore various DWA scenarios. These experiments are motivated by the opportunities presented by the approval of the FACET facility at SLAC, as well as unique pulse-train wakefield drivers at BNL. The SLAC experiments permit further exploration of the multi-GeV/m envelope in DWAs, and will entail investigations of novel materials (e.g. CVD diamond) and geometries (Bragg cylindrical structures, slab-symmetric DWAs), and have an over-riding goal of demonstrating >GeV acceleration in {approx}33 cm DWA tubes. In the nearer term before FACET's commissioning, we are performing measurements at the BNL ATF, in which we drive {approx}50-200 MV/m fields with single pulses or pulse trains, and observe resonantly driven CCR as well as deflection modes. These experiments are of high relevance to enhancing linear collider DWA designs, as they will demonstrate potential for high efficiency operation with pulse trains, and explore transverse modes for the first time.

  19. High Frequency, High Gradient Dielectric Wakefield Acceleration Experiments at SLAC and BNL

    SciTech Connect

    Rosenzweig, James; Travish, Gil; Hogan, Mark; Muggli, Patric; /Southern California U.

    2012-07-05

    Given the recent success of >GV/m dielectric wakefield accelerator (DWA) breakdown experiments at SLAC, and follow-on coherent Cerenkov radiation production at the UCLA Neptune, a UCLA-USC-SLAC collaboration is now implementing a new set of experiments that explore various DWA scenarios. These experiments are motivated by the opportunities presented by the approval of FACET facility at SLAC, as well as unique pulse-train wakefield drivers at BNL. The SLAC experiments permit further exploration of the multi-GeV/m envelope in DWAs, and will entail investigations of novel materials (e.g. CVD diamond) and geometries (Bragg cylindrical structures, slab-symmetric DWAs), and have an over-riding goal of demonstrating >GeV acceleration in {approx}33 cm DWA tubes. In the nearer term before FACET's commissioning, we are planning measurements at the BNL ATF, in which we drive {approx}50-200 MV/m fields with single pulses or pulse trains. These experiments are of high relevance to enhancing linear collider DWA designs, as they will demonstrate potential for efficient operation with pulse trains.

  20. Wakefield Simulations for the Laser Acceleration Experiment at SLAC

    SciTech Connect

    Ng, Johnny

    2012-04-18

    Laser-driven acceleration in dielectric photonic band gap structures can provide gradients on the order of GeV/m. The small transverse dimension of the structure, on the order of the laser wavelength, presents interesting wakefield-related issues. Higher order modes can seriously degrade beam quality, and a detailed understanding is needed to mitigate such effects. On the other hand, wakefields also provide a direct way to probe the interaction of a relativistic bunch with the synchronous modes supported by the structure. Simulation studies have been carried out as part of the effort to understand the impact on beam dynamics, and to compare with data from beam experiments designed to characterize candidate structures. In this paper, we present simulation results of wakefields excited by a sub-wavelength bunch in optical photonic band gap structures.

  1. The UCLA/SLAC Ultra-High Gradient Cerenkov Wakefield Accelerator Experiment

    SciTech Connect

    Thompson, M.C.; Badakov, H.; Rosenzweig, J.B.; Travish, G.; Hogan, M.; Ischebec, R.; Siemann, R.; Walz, D.; Scott, A.; Yoder, R.; /Manhattan Coll., Riverdale

    2006-01-25

    An experiment is planned to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range. This new UCLA/SLAC/USC collaboration will take advantage of the unique SLAC FFTB electron beam and its demonstrated ultra-short pulse lengths and high currents (e.g., {delta}{sub z} = 20 {micro}m at Q = 3 nC). The electron beam will be focused down and sent through varying lengths of fused silica capillary tubing with two different sizes: ID = 200 {micro}m/OD = 325 {micro}m and ID = 100 {micro}m/OD = 325 {micro}m. The pulse length of the electron beam will be varied in order to alter the accelerating gradient and probe the breakdown threshold of the dielectric structures. In addition to breakdown studies, we plan to collect and measure coherent Cerenkov radiation emitted from the capillary tube to gain information about the strength of the accelerating fields.

  2. Facility for Advanced Accelerator Experimental Tests (FACET) at SLAC and its Radiological Considerations

    SciTech Connect

    Mao, X.S.; Leitner, M.Santana; Vollaire, J.

    2011-08-22

    Facility for Advanced Accelerator Experimental Tests (FACET) in SLAC will be used to study plasma wakefield acceleration. FLUKA Monte Carlo code was used to design a maze wall to separate FACET project and LCLS project to allow persons working in FACET side during LCLS operation. Also FLUKA Monte Carlo code was used to design the shielding for FACET dump to get optimum design for shielding both prompt and residual doses, as well as reducing environmental impact. FACET will be an experimental facility that provides short, intense pulses of electrons and positrons to excite plasma wakefields and study a variety of critical issues associated with plasma wakefield acceleration [1]. This paper describes the FACET beam parameters, the lay-out and its radiological issues.

  3. Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC

    ScienceCinema

    Andrei Seryi

    2010-01-08

    Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators.  FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.  

  4. Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC

    SciTech Connect

    Andrei Seryi

    2009-09-09

    Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators.  FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.  

  5. 600 kV modulator design for the SLAC Next Linear Collider Test Accelerator

    SciTech Connect

    Harris, K.; de Lamare, J.; Nesterov, V.; Cassel, R.

    1992-07-01

    Preliminary design for the SLAC Next Linear Collider Test Accelerator (NLCTA) requires a pulse power source to produce a 600 kV, 600 A, 1.4 {mu}s, 0.1% flat top pulse with rise and fall times of approximately 100 ns to power an X-Band klystron with a microperveance of 1.25 at {approx} 100 MW peak RF power. The design goals for the modulator, including those previously listed, are peak modulator pulse power of 340 MW operating at 120 Hz. A three-stage darlington pulse-forming network, which produces a >100 kV, 1.4 {mu}s pulse, is coupled to the klystron load through a 6:1 pulse transformer. Careful consideration of the transformer leakage inductance, klystron capacitance, system layout, and component choice is necessary to produce the very fast rise and fall times at 600 kV operating continuously at 120 Hz.

  6. An Ultra-High Gradient Cherenkov Wakefield Acceleration Experiment at SLAC FFTB

    SciTech Connect

    Rosenzweig, J.B.; Hoover, S.; Hogan, M.J.; Muggli, P.; Thompson, M.; Travish, G.; Yoder, R.; /UCLA /SLAC /Southern California U.

    2005-08-02

    The creation of ultra-high current, ultra-short pulse beams Q=3 nC, {sigma}{sub z} = 20{micro}m at the SLAC FFTB has opened the way for very high gradient plasma wakefield acceleration experiments. We study here the use of these beams in a proposed Cherenkov wakefield experiment, where one may excite electromagnetic wakes in a simple dielectric tube with inner diameter of few 100 microns that exceed the GV/m level. We discuss the scaling of the fields with design geometric design parameters, and choice of dielectric. We also examine measurable aspects of the experiment, such as the total coherent Cerenkov radiation energy one may collect, and the expected aspects of dielectric breakdown at high fields.

  7. Facility for Advanced Accelerator Experimental Tests at SLAC (FACET) Conceptual Design Report

    SciTech Connect

    Amann, J.; Bane, K.; /SLAC

    2009-10-30

    This Conceptual Design Report (CDR) describes the design of FACET. It will be updated to stay current with the developing design of the facility. This CDR begins as the baseline conceptual design and will evolve into an 'as-built' manual for the completed facility. The Executive Summary, Chapter 1, gives an introduction to the FACET project and describes the salient features of its design. Chapter 2 gives an overview of FACET. It describes the general parameters of the machine and the basic approaches to implementation. The FACET project does not include the implementation of specific scientific experiments either for plasma wake-field acceleration for other applications. Nonetheless, enough work has been done to define potential experiments to assure that the facility can meet the requirements of the experimental community. Chapter 3, Scientific Case, describes the planned plasma wakefield and other experiments. Chapter 4, Technical Description of FACET, describes the parameters and design of all technical systems of FACET. FACET uses the first two thirds of the existing SLAC linac to accelerate the beam to about 20GeV, and compress it with the aid of two chicanes, located in Sector 10 and Sector 20. The Sector 20 area will include a focusing system, the generic experimental area and the beam dump. Chapter 5, Management of Scientific Program, describes the management of the scientific program at FACET. Chapter 6, Environment, Safety and Health and Quality Assurance, describes the existing programs at SLAC and their application to the FACET project. It includes a preliminary analysis of safety hazards and the planned mitigation. Chapter 7, Work Breakdown Structure, describes the structure used for developing the cost estimates, which will also be used to manage the project. The chapter defines the scope of work of each element down to level 3.

  8. Preliminary Results from the UCLA/SLAC Ultra-High Gradient CerenkovWakefield Accelerator Experiment

    SciTech Connect

    Thompson, M.C.; Badakov, H.; Rosenzweig, J.B.; Travish, G.; Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; Muggli, P.; Scott, A.; Yoder, R.; /Manhattan Coll., Riverdale

    2008-02-06

    The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. This experiment takes advantage of the unique SLAC FFTB electron beam and its demonstrated ultra-short pulse lengths and high currents (e.g., {sigma}{sub z} = 20 {micro}m at Q = 3 nC). The FFTB electron beam has been successfully focused down and sent through varying lengths of fused silica capillary tubing with two different sizes: ID = 200 {micro}m/OD = 325 {micro}m and ID = 100 {micro}m/OD = 325 {micro}m. The pulse length of the electron beam was varied in the range 20 {micro}m < {sigma}{sub z} < 100 {micro}m which produced a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments we plan to collect and measure coherent Cerenkov radiation emitted from the capillary tube to gain more information about the strength of the accelerating fields.

  9. FACET: SLAC___s New User Facility

    SciTech Connect

    Clarke, C.I.; Decker, F.-J.; England, R.J.; Erickson, R.A.; Hast, C.; Hogan, M.J.; Li, S.Z.; Litos, M.D.; Nosochkov, Y.; Seeman, J.T.; Sheppard, J.; Wienands, U.; Woodley, M.; Yocky, G.; /SLAC

    2012-05-16

    FACET (Facility for Advanced Accelerator Experimental Tests) is a new User Facility at SLAC National Accelerator Laboratory. The first User Run started in spring 2012 with 20 GeV, 3 nC electron beams. The facility is designed to provide short (20 {micro}m) bunches and small (20 {micro}m wide) spot sizes, producing uniquely high power beams. FACET supports studies from many fields but in particular those of Plasma Wakefield Acceleration and Dielectric Wakefield Acceleration. The creation of drive and witness bunches and shaped bunch profiles is possible with 'Notch' Collimation. FACET is also a source of THz radiation for material studies. Positrons will be available at FACET in future user runs. We present the User Facility and the available tools and opportunities for future experiments.

  10. SLAC All Access: FACET

    ScienceCinema

    Hogan, Mark

    2014-09-15

    SLAC's Facility for Advanced Accelerator Experimental Tests, or FACET, is a test-bed where researchers are developing the technologies required for particle accelerators of the future. Scientists from all over the world come to explore ways of improving the power and efficiency of the particle accelerators used in basic research, medicine, industry and other areas important to society. In this video, Mark Hogan, head of SLAC's Advanced Accelerator Research Department, offers a glimpse into FACET, which uses part of SLAC's historic two-mile-long linear accelerator.

  11. SLAC All Access: FACET

    SciTech Connect

    Hogan, Mark

    2012-07-05

    SLAC's Facility for Advanced Accelerator Experimental Tests, or FACET, is a test-bed where researchers are developing the technologies required for particle accelerators of the future. Scientists from all over the world come to explore ways of improving the power and efficiency of the particle accelerators used in basic research, medicine, industry and other areas important to society. In this video, Mark Hogan, head of SLAC's Advanced Accelerator Research Department, offers a glimpse into FACET, which uses part of SLAC's historic two-mile-long linear accelerator.

  12. Observation and Characterization of Coherent Optical Radiation and Microbunching Instability in the SLAC Next Linear Collider Test Accelerator

    SciTech Connect

    Weathersby, S.; Dunning, M.; Hast, C.; Jobe, K.; McCormick, D.; Nelson, J.; Xiang, D.; /SLAC

    2011-06-02

    The NLC Test Accelerator (NLCTA) at SLAC is currently configured for a proof-of-principle echo-enabled harmonic generation (EEHG) experiment using an 120 MeV beam. During commissioning, unexpected coherent optical undulator radiation (CUR) and coherent optical transition radiation (COTR) was observed when beam is accelerated off-crest and compressed after the chicanes. The CUR and COTR is likely due to a microbunching instability where the initial small ripples in cathode drive laser is compressed and amplified. In this paper we present the observation and characterization of the CUR, COTR and microbunching instability at NLCTA.

  13. ATLAS accelerator laboratory report

    SciTech Connect

    Den Hartog, P.

    1986-01-01

    The operation of the ATLAS Accelerator is reported. Modifications are reported, including the installation of conductive tires for the Pelletron chain pulleys, installation of a new high frequency sweeper system at the entrance to the linac, and improvements to the rf drive ports of eight resonators to correct failures in the thermally conductive ceramic insulators. Progress is reported on the positive-ion injector upgrade for ATLAS. Also reported are building modifications and possible new uses for the tandem injector. (LEW)

  14. Introduction to high-energy physics and the Stanford Linear Accelerator Center (SLAC)

    SciTech Connect

    Clearwater, S.

    1983-03-01

    The type of research done at SLAC is called High Energy Physics, or Particle Physics. This is basic research in the study of fundamental particles and their interactions. Basic research is research for the sake of learning something. Any practical application cannot be predicted, the understanding is the end in itself. Interactions are how particles behave toward one another, for example some particles attract one another while others repel and still others ignore each other. Interactions of elementary particles are studied to reveal the underlying structure of the universe.

  15. GPS Activities at SLAC

    SciTech Connect

    Behrend, Dirk

    2002-11-19

    The Alignment Engineering Group of the Stanford Linear Accelerator Center (SLAC) started to use RTK (real-time kinematic) GPS equipment in order to perform structure mapping and GIS-related tasks on the SLAC campus. In a first step a continuously observing GPS station (SLAC M40) was set up. This station serves as master control station for all differential GPS activities on site and its coordinates have been determined in the well-defined global geodetic datum ITRF2000 at a given reference epoch. Some trials have been performed to test the RTK method. The tests have proven RTK to be very fast and efficient.

  16. SLAC linear collider

    SciTech Connect

    Richter, B.; Bell, R.A.; Brown, K.L.

    1980-06-01

    The SLAC LINEAR COLLIDER is designed to achieve an energy of 100 GeV in the electron-positron center-of-mass system by accelerating intense bunches of particles in the SLAC linac and transporting the electron and positron bunches in a special magnet system to a point where they are focused to a radius of about 2 microns and made to collide head on. The rationale for this new type of colliding beam system is discussed, the project is described, some of the novel accelerator physics issues involved are discussed, and some of the critical technical components are described.

  17. The SLAC P2 Marx

    SciTech Connect

    Kemp, Mark; Benwell, Andrew; Burkhart, Craig; MacNair, David; Nguyen1, Minh; /SLAC

    2012-07-05

    A proposed high energy physics accelerator, the International Linear Collider, will require greater than five hundred rf stations. Each station is composed of a klystron driven by a modulator. Recently, the SLAC P2 Marx was designated the baseline modulator for the ILC. This paper describes some key features of this modulator and presents recent experimental results. The P2 Marx is presently being transported to another facility for lifetime testing. Here, we will gain understanding of how the Marx performs into a klystron load and gain experience operating the Marx for longer periods. Long term plans include the possibility of using this rf station for L-band technology demonstration at SLAC. While the Marx was designed with the ILC in mind, the topology can be readily applied to several different applications. We are currently evaluating the use of the topology for ESS, CLIC, and upgrades for systems at Fermi National Accelerator Laboratory. Because of the modular nature of the cell and the robustness of the control system, many different combinations of series and parallel operation are possible along with different load currents and pulse shapes.

  18. A summary of ground motion effects at SLAC (Stanford Linear Accelerator Center) resulting from the Oct 17th 1989 earthquake

    SciTech Connect

    Ruland, R.E.

    1990-08-01

    Ground motions resulting from the October 17th 1989 (Loma Prieta) earthquake are described and can be correlated with some geologic features of the SLAC site. Recent deformations of the linac are also related to slow motions observed over the past 20 years. Measured characteristics of the earthquake are listed. Some effects on machine components and detectors are noted. 18 refs., 16 figs.

  19. Vehicle Systems Integration Laboratory Accelerates Powertrain Development

    SciTech Connect

    2014-04-15

    ORNL's Vehicle Systems Integration (VSI) Laboratory accelerates the pace of powertrain development by performing prototype research and characterization of advanced systems and hardware components. The VSI Lab is capable of accommodating a range of platforms from advanced light-duty vehicles to hybridized Class 8 powertrains with the goals of improving overall system efficiency and reducing emissions.

  20. Vehicle Systems Integration Laboratory Accelerates Powertrain Development

    ScienceCinema

    None

    2014-06-25

    ORNL's Vehicle Systems Integration (VSI) Laboratory accelerates the pace of powertrain development by performing prototype research and characterization of advanced systems and hardware components. The VSI Lab is capable of accommodating a range of platforms from advanced light-duty vehicles to hybridized Class 8 powertrains with the goals of improving overall system efficiency and reducing emissions.

  1. X-ray Astronomy at SLAC

    SciTech Connect

    Saz Parkinson, P

    2005-04-06

    The USA (Unconventional Stellar Aspect) experiment was launched in February of 1999 and operated for approximately 18 months. Group K at SLAC (Stanford Linear Accelerator Center) participated in this experiment along with the Naval Research Laboratory (NRL). The author discusses the USA experiment and the data accumulated, along with some of the results obtained from the observations of such objects as the extragalactic BL Lac object 1ES1959+65, the Black Hole Candidate (BHC) XTE J1118+480, and the eccentric X-ray binary system Circinus X-1.

  2. Accelerated laboratory weathering of acrylic lens materials

    NASA Astrophysics Data System (ADS)

    Arndt, Thomas; Richter, Steffen; Kogler, René; Pasierb, Mike; Walby, Christopher

    2015-09-01

    Flat samples from various poly(methyl methacrylate) (PMMA) formulations were subjected to outdoor weathering in Arizona and Florida, EMMAQUA® accelerated outdoor weathering, and two accelerated laboratory weathering procedures at 3 Sun irradiance which, imitate dry (Arizona) and wet (Florida) conditions. The main mode of degradation is yellowing and not the generation of haze for any weathering procedure within the investigated radiant exposure. Higher UV absorber concentrations lead to smaller changes in optical properties and in the resulting relative concentrator photovoltaic (CPV) module efficiencies. Comparison of sample properties after various weathering procedures reveals that the influence of weathering factors other than radiant exposure depends on the sample as well.

  3. Numerical and laboratory simulations of auroral acceleration

    SciTech Connect

    Gunell, H.; De Keyser, J.; Mann, I.

    2013-10-15

    The existence of parallel electric fields is an essential ingredient of auroral physics, leading to the acceleration of particles that give rise to the auroral displays. An auroral flux tube is modelled using electrostatic Vlasov simulations, and the results are compared to simulations of a proposed laboratory device that is meant for studies of the plasma physical processes that occur on auroral field lines. The hot magnetospheric plasma is represented by a gas discharge plasma source in the laboratory device, and the cold plasma mimicking the ionospheric plasma is generated by a Q-machine source. In both systems, double layers form with plasma density gradients concentrated on their high potential sides. The systems differ regarding the properties of ion acoustic waves that are heavily damped in the magnetosphere, where the ion population is hot, but weakly damped in the laboratory, where the discharge ions are cold. Ion waves are excited by the ion beam that is created by acceleration in the double layer in both systems. The efficiency of this beam-plasma interaction depends on the acceleration voltage. For voltages where the interaction is less efficient, the laboratory experiment is more space-like.

  4. Laboratory Reconnection Experiments - heating and particle acceleration

    NASA Astrophysics Data System (ADS)

    Ono, Yasushi

    Recent laboratory merging/ reconnection experiments have solved a number of key physics of magnetic reconnection: 1) reconnection heating/ acceleration, 2) fast reconnection mechanisms, 3) plasmoid reconnection, 4) non-steady reconnection and 5) non-thermal particle acceleration using new kinetic interpretations. Especially, significant ion temperatures 1.2keV were documented in the world-largest tokamak merging experiment: MAST after detailed 2D elucidation of ion and electron heating characteristics in TS-3 and 4 merging experiments. The measured 2D contours of ion and electron temperatures in TS-3, 4 and MAST reveal ion heating in the downstream by reconnection outflow and electron heating around the X-point by ohmic heating of current sheet. Their detailed heating mechanisms were further investigated by comparing those results with particle simulations developed by NIFS. The ion acceleration mechanism is mostly parallel acceleration by reconnection electric field and partly perpendicular acceleration by electrostatic potential. The fast shock and ion viscosity are the major dumping (heating) mechanisms for the accelerated ions. We successfully applied the reconnection heating - typically 10-50MW to the high-beta spherical tokamak formation and heating. This paper will review major progresses in those international and interdisciplinary merging tokamak experiments.

  5. SLAC All Access: Laser Labs

    ScienceCinema

    Minitti, Mike; Woods Mike

    2014-06-03

    From supermarket checkouts to video game consoles, lasers are ubiquitous in our lives. Here at SLAC, high-power lasers are critical to the cutting-edge research conducted at the laboratory. But, despite what you might imagine, SLAC's research lasers bear little resemblance to the blasters and phasers of science fiction. In this edition of All Access we put on our safety goggles for a peek at what goes on inside some of SLAC's many laser labs. LCLS staff scientist Mike Minitti and SLAC laser safety officer Mike Woods detail how these lasers are used to study the behavior of subatomic particles, broaden our understanding of cosmic rays and even unlock the mysteries of photosynthesis.

  6. SLAC All Access: Laser Labs

    SciTech Connect

    Minitti, Mike; Woods Mike

    2013-03-01

    From supermarket checkouts to video game consoles, lasers are ubiquitous in our lives. Here at SLAC, high-power lasers are critical to the cutting-edge research conducted at the laboratory. But, despite what you might imagine, SLAC's research lasers bear little resemblance to the blasters and phasers of science fiction. In this edition of All Access we put on our safety goggles for a peek at what goes on inside some of SLAC's many laser labs. LCLS staff scientist Mike Minitti and SLAC laser safety officer Mike Woods detail how these lasers are used to study the behavior of subatomic particles, broaden our understanding of cosmic rays and even unlock the mysteries of photosynthesis.

  7. Beam dynamics enhancement due to accelerating field symmetrization in the BNL/SLAC/UCLA 1.6 cell S-band photocathode RF gun

    SciTech Connect

    Palmer, D.T.; Miller, R.H.; Wang, X.J.; Ben-Zvi, I.

    1997-07-01

    A 1.6 cell photocathode S-Band gun developed by the BNL/SLAC/UCLA collaboration is now in operation at the Brookhaven Accelerator Test Facility (ATF). One of the main features of this RF gun is the symmetrization of the RF coupling iris with an identical vacuum pumping port located in the full cell. The effects of the asymmetry caused by the RF coupling iris were experimentally investigated by positioning a metallic plunger at the back wall of the vacuum port iris. The higher order modes produced were studied using electron beamlets with 8-fold symmetry. The 8-fold beamlets were produced by masking the laser beam. These experimental results indicate that the integrated electrical center and the geometrical center of the gun are within 175 {micro}m. Which is within the laser alignment tolerance of 250 {micro}m.

  8. FACET: The New User Facility at SLAC

    SciTech Connect

    Clarke, C.I.; Decker, F.J.; Erikson, R.; Hast, C.; Hogan, M.J.; Iverson, R.; Li, S.Z.; Nosochkov, Y.; Phinney, N.; Sheppard, J.; Wienands, U.; Woodley, M.; Yocky, G.; Seryi, A.; Wittmer, W.; /Michigan State U.

    2011-12-13

    FACET (Facility for Advanced Accelerator and Experimental Tests) is a new User Facility at SLAC National Accelerator Laboratory. Its high power electron and positron beams make it a unique facility, ideal for beam-driven Plasma Wakefield Acceleration studies. The first 2 km of the SLAC linac produce 23 GeV, 3.2 nC electron and positron beams with short bunch lengths of 20 {mu}m. A final focusing system can produce beam spots 10 {mu}m wide. User-aided Commissioning took place in summer 2011 and FACET will formally come online in early 2012. We present the User Facility, the current features, planned upgrades and the opportunities for further experiments. Accelerators are our primary tool for discovering the fundamental laws to the universe. Each new frontier we probe requires a new, more powerful method. Accelerators are therefore increasing in size and cost. The future of this field requires new accelerating techniques that can reach the high energies required over shorter distances. New concepts for high gradient acceleration include utilizing the wakes in plasma and dielectric and metallic structures. FACET was built to provide a test bed for novel accelerating concepts with its high charge and highly compressed beams. As a test facility unlike any other, it has also attracted groups interested in beam diagnostic techniques and terahertz studies. The first phase of the construction was completed in May 2011. Beam commissioning began in June and was interleaved with the installation of five experiments. Users were invited to aid with the commissioning for the month of August during which time experimental hardware and software were checked out and some first measurements were taken. FACET is currently in the process of becoming a Department of Energy User Facility for High Energy Physics.

  9. Observation of particle acceleration in laboratory magnetosphere

    SciTech Connect

    Kawazura, Y.; Yoshida, Z.; Nishiura, M.; Saitoh, H.; Yano, Y.; Nogami, T.; Sato, N.; Yamasaki, M.; Kashyap, A.; Mushiake, T.

    2015-11-15

    The self-organization of magnetospheric plasma is brought about by inward diffusion of magnetized particles. Not only creating a density gradient toward the center of a dipole magnetic field, the inward diffusion also accelerates particles and provides a planetary radiation belt with high energy particles. Here, we report the first experimental observation of a “laboratory radiation belt” created in the ring trap 1 device. By spectroscopic measurement, we found an appreciable anisotropy in the ion temperature, proving the betatron acceleration mechanism which heats particles in the perpendicular direction with respect to the magnetic field when particles move inward. The energy balance model, including the heating mechanism, explains the observed ion temperature profile.

  10. Future Proof for Physics: Preserving the Record of SLAC

    ERIC Educational Resources Information Center

    Deken, Jean Marie

    2005-01-01

    This article provides a brief introduction to the Stanford Linear Accelerator Center (SLAC), discusses the origins of the SLAC Archives and History Office, its present-day operations, and the present and future challenges it faces in attempting to preserve an accurate historical record of SLAC's activities. (Contains 21 notes.)

  11. Accelerated laboratory weathering of acrylic lens materials

    NASA Astrophysics Data System (ADS)

    Arndt, Thomas; Richter, Steffen; Kogler, René; Pasierb, Mike; Walby, Christopher

    2014-09-01

    Flat samples from various PMMA formulations subjected to accelerated laboratory weathering in an "Atlas Xenotest Alpha +" weathering device operating at 3 Sun irradiance remain transparent after 6.48GJ/m2 radiant exposure (300 - 400nm). Transmittance is reduced and yellowness index increases. However, the amount of change depends largely on the PMMA formulation. Higher UV absorber concentrations lead to smaller changes in optical properties. Based on a model of CPV efficiency for a particular power train, relative losses of efficiency are between 1 and 28%. Performance regarding these properties can be linked to the UV absorber type and concentrations used.

  12. SLAC All Access: Vacuum Microwave Device Department

    SciTech Connect

    Haase, Andy

    2012-10-09

    The Vacuum Microwave Device Department (VMDD) builds the devices that make SLAC's particle accelerators go. These devices, called klystrons, generate intense waves of microwave energy that rocket subatomic particles up to nearly the speed of light.

  13. SLAC All Access: Vacuum Microwave Device Department

    ScienceCinema

    Haase, Andy

    2014-06-13

    The Vacuum Microwave Device Department (VMDD) builds the devices that make SLAC's particle accelerators go. These devices, called klystrons, generate intense waves of microwave energy that rocket subatomic particles up to nearly the speed of light.

  14. SLAC Linac Preparations for FACET

    SciTech Connect

    Erickson, R.; Bentson, L.; Kharakh, D.; Owens, A.; Schuh, P.; Seeman, J.; Sheppard, J.C.; Stanek, M.; Wittmer, W.; Yocky, G.; Wienands, U.; /SLAC

    2011-02-07

    The SLAC 3km linear electron accelerator has been cut at the two-thirds point to provide beams to two independent programs. The last third provides the electron beam for the Linac Coherent Light Source (LCLS), leaving the first two-thirds available for FACET, the new experimental facility for accelerator science and test beams. In this paper, we describe this separation and projects to prepare the linac for the FACET experimental program.

  15. Accelerator Mass Spectrometry in Laboratory Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Nusair, O.; Bauder, W.; Gyürky, G.; Paul, M.; Collon, P.; Fülöp, Zs; Greene, J.; Kinoshita, N.; Palchan, T.; Pardo, R.; Rehm, K. E.; Scott, R.; Vondrasek, R.

    2016-01-01

    The extreme sensitivity and discrimination power of accelerator mass spectrometry (AMS) allows for the search and the detection of rare nuclides either in natural samples or produced in the laboratory. At Argonne National Laboratory, we are developing an AMS setup aimed in particular at the detection of medium and heavy nuclides, relying on the high ion energy achievable with the ATLAS superconducting linear accelerator and on gas-filled magnet isobaric separation. The setup was recently used for the detection of the 146Sm p-process nuclide and for a new determination of the 146Sm half-life (68.7 My). AMS plays an important role in the measurement of stellar nuclear reaction cross sections by the activation method, extending thus the technique to the study of production of long-lived radionuclides. Preliminary measurements of the 147Sm(γ,n)146Sm are described. A measurement of the 142Nd(α,γ)146Sm and 142Nd(α,n)145Sm reactions is in preparation. A new laser-ablation method for the feeding of the Electron Cyclotron Resonance (ECR) ion source is described.

  16. SLC Energy Upgrade Program at SLAC

    SciTech Connect

    Loew, G.A.; Allen, M.A.; Cassel, R.L.; Dean, N.R.; Konrad, G.T.; Koontz, R.F.; Lebacqz, J.V.

    1985-03-01

    The SLAC Linear Collider (SLC) must reach a nominal center-of-mass energy of 100 GeV to fulfill its high energy physics goals. This paper describes the energy upgrade program that is being implemented on the SLAC linear accelerator to meet these goals. It includes a discussion of the design requirements and available technical options, the rationale for the adopted solution, and the technical problems involved in the engineering and production of klystrons and modulators.

  17. Operational experience on the Brookhaven National Laboratory Accelerator Test Facility

    SciTech Connect

    Batchelor, K.; Babzien, M.; Ben-Zvi, I.

    1994-09-01

    Brookhaven National Laboratory Accelerator Test Facility is a laser-electron linear accelerator complex designed to provide high brightness beams for testing of advanced acceleration concepts and high power pulsed photon sources. Results of electron beam parameters attained during the commissioning of the nominally 45 MeV energy machine are presented.

  18. Computer control of rf at SLAC

    SciTech Connect

    Schwarz, H.D.

    1985-03-01

    The Stanford Linear Accelerator is presently upgraded for the SLAC Linear Collider project. The energy is to be increased from approximately 31 GeV to 50 GeV. Two electron beams and one positron beam are to be accelerated with high demands on the quality of the beams. The beam specifications are shown. To meet these specifications, all parameters influencing the beams have to be under tight control and continuous surveillance. This task is accomplished by a new computer system implemented at SLAC which has, among many other functions, control over rf accelerating fields. 13 refs., 8 figs., 2 tabs.

  19. Resonant Kicker System Development at SLAC

    SciTech Connect

    Beukers, Tony; Krzaszczak, John; Larrus, Marc; Lira, Antonio de; /SLAC

    2009-04-27

    The design and installation of the Linear Coherent Light Source [1] at SLAC National Accelerator Laboratory has included the development of a kicker system for selective beam bunch dumping. The kicker is based on an LC resonant topology formed by the 50 uF energy storage capacitor and the 64 uH air core magnet load which has a sinusoidal pulse period of 400us. The maximum magnet current is 500 A. The circuit is weakly damped, allowing most of the magnet energy to be recovered in the energy storage capacitor. The kicker runs at a repetition rate of 120Hz. A PLC-based control system provides remote control and monitoring of the kicker via EPICS protocol. Fast timing and interlock signals are converted by discrete peak-detect and sample-hold circuits into DC signals that can be processed by the PLC. The design and experimental characterization of the system are presented.

  20. RF breakdown experiments at SLAC

    SciTech Connect

    Laurent, L.; Vlieks, A.; Pearson, C.; Caryotakis, G.; Luhmann, N.C.

    1999-05-01

    RF breakdown is a critical issue in the conditioning of klystrons, accelerator sections, and rf components for the next linear collider (NLC), as well as other high gradient accelerators and high power microwave sources. SLAC is conducting a series of experiments using an X-band traveling wave ring to characterize the processes and trigger mechanisms associated with rf breakdown. The goal of the research is to identify materials, processes, and manufacturing methods that will increase the breakdown threshold and minimize the time required for conditioning. {copyright} {ital 1999 American Institute of Physics.}

  1. Linear collider development at SLAC

    SciTech Connect

    Irwin, J.

    1993-08-01

    Linear collider R&D at SLAC comprises work on the present Stanford Linear Collider (SLC) and work toward the next linear collider (NLC). Recent SLC developments are summarized. NLC studies are divided into hardware-based and theoretical. We report on the status of the NLC Test Accelerator (NLCTA) and the final focus test beam (FFTB), describe plans for ASSET, an installation to measure accelerator structure wakefields, and mention IR design developments. Finally we review recent NLC theoretical studies, ending with the author`s view of next linear collider parameter sets.

  2. Recent Upgrade of the Klystron Modulator at SLAC

    SciTech Connect

    Nguyen, M.N.; Burkhart, C.P.; Lam, B.K.; Morris, B.; /SLAC

    2011-11-04

    The SLAC National Accelerator Laboratory employs 244 klystron modulators on its two-mile-long linear accelerator that has been operational since the early days of the SLAC establishment in the sixties. Each of these original modulators was designed to provide 250 kV, 262 A and 3.5 {mu}S at up to 360 pps using an inductance-capacitance resonant charging system, a modified type-E pulse-forming network (PFN), and a pulse transformer. The modulator internal control comprised of large step-start resistor-contactors, vacuum-tube amplifiers, and 120 Vac relays for logical signals. A major, power-component-only upgrade, which began in 1983 to accommodate the required beam energy of the SLAC Linear Collider (SLC) project, raised the modulator peak output capacity to 360 kV, 420 A and 5.0 {mu}S at a reduced pulse repetition rate of 120 pps. In an effort to improve safety, performance, reliability and maintainability of the modulator, this recent upgrade focuses on the remaining three-phase AC power input and modulator controls. The upgrade includes the utilization of primary SCR phase control rectifiers, integrated fault protection and voltage regulation circuitries, and programmable logic controllers (PLC) -- with an emphasis on component physical layouts for safety and maintainability concerns. In this paper, we will describe the design and implementation of each upgraded component in the modulator control system. We will also report the testing and present status of the modified modulators.

  3. Plasma wakefield acceleration at CLARA facility in Daresbury Laboratory

    NASA Astrophysics Data System (ADS)

    Xia, G.; Nie, Y.; Mete, O.; Hanahoe, K.; Dover, M.; Wigram, M.; Wright, J.; Zhang, J.; Smith, J.; Pacey, T.; Li, Y.; Wei, Y.; Welsch, C.

    2016-09-01

    A plasma accelerator research station (PARS) has been proposed to study the key issues in electron driven plasma wakefield acceleration at CLARA facility in Daresbury Laboratory. In this paper, the quasi-nonlinear regime of beam driven plasma wakefield acceleration is analysed. The wakefield excited by various CLARA beam settings are simulated by using a 2D particle-in-cell (PIC) code. For a single drive beam, an accelerating gradient up to 3 GV/m can be achieved. For a two bunch acceleration scenario, simulation shows that a witness bunch can achieve a significant energy gain in a 10-50 cm long plasma cell.

  4. Physics results with polarized electrons at SLAC

    SciTech Connect

    Prescott, C.Y.

    1996-03-01

    Polarized electron beams can play an important role in the dynamics of interactions at high energies. Polarized electron beams at SLAC have been an important part of the physics program since 1970, when they were first proposed for use in testing the spin structure of the proton. Since 1992, the SLAC linear accelerator and the SLC have operated solely with polarized electrons, providing data for tests of QCD in studies of the spin structure of the nucleon and tests of the electroweak sector of the Standard Model. In the following sections, the performance of the source is summarized, and some of the recent results using the polarized beams are discussed.

  5. Polarization at SLAC

    SciTech Connect

    Woods, M.

    1995-01-01

    A highly polarized electron beam is a key feature. for the Current physics program at SLAC. An electron beam polarization of 80% can now be routinely achieved for typically 5000 hours of machine operation per year. Two main Physics programs utilize the polarized beam. Fixed target experiments in End Station A study the collision of polarized electrons with polarized nuclear targets to elucidate the spin structure of the nucleon and to provide an important test of QCD. Using the SLAC Linear Collider, collisions of polarized electrons with unpolarized positrons allow precise measurements of parity violation in the Z-fermion couplings and provide a very precise measurement of tile weak mixing angle. This paper discusses polarized beam operation at SLAC, and gives an overview of the polarized physics program.

  6. The target laboratory of the Pelletron Accelerator's facilities

    SciTech Connect

    Ueta, Nobuko; Pereira Engel, Wanda Gabriel

    2013-05-06

    A short report on the activities developed in the Target Laboratory, since 1970, will be presented. Basic target laboratory facilities were provided to produce the necessary nuclear targets as well as the ion beam stripper foils. Vacuum evaporation units, a roller, a press and an analytical balance were installed in the Oscar Sala building. A brief historical report will be presented in commemoration of the 40{sup th} year of the Pelletron Accelerator.

  7. The target laboratory of the Pelletron Accelerator's facilities

    NASA Astrophysics Data System (ADS)

    Ueta, Nobuko; Pereira Engel, Wanda Gabriel

    2013-05-01

    A short report on the activities developed in the Target Laboratory, since 1970, will be presented. Basic target laboratory facilities were provided to produce the necessary nuclear targets as well as the ion beam stripper foils. Vacuum evaporation units, a roller, a press and an analytical balance were installed in the Oscar Sala building. A brief historical report will be presented in commemoration of the 40th year of the Pelletron Accelerator.

  8. Magnetic septa for the Saskatchewan Accelerator Laboratory (SAL)

    SciTech Connect

    Figley, C.B. )

    1990-12-01

    A design was investigated for two magnets now in permanent use at the Saskatchewan Accelerator Laboratory (SAL). The compact septa incorporated a novel cooling technique for the thin aluminum sheets forming the coils. These magnets have operated successfully for several years. Concepts for improving the duty factor and peak field of the septa by using power modulators are considered.

  9. Short wavelength FELs using the SLAC linac

    NASA Astrophysics Data System (ADS)

    Winick, H.; Bane, K.; Boyce, R.; Cobb, J.; Loew, G.; Morton, P.; Nuhn, H.-D.; Paterson, J.; Pianetta, P.; Raubenheimer, T.; Seeman, J.; Tatchyn, R.; Vylet, V.; Pellegrini, C.; Rosenzweig, J.; Travish, G.; Prosnitz, D.; Scharlemann, E. T.; Halbach, K.; Kim, K.-J.; Schlueter, R.; Xie, M.; Bonifacio, R.; De Salvo, L.; Pierini, P.

    1994-08-01

    Recent technological developments have opened the possibility to construct a device which we call a linac coherent light source (LCLS) (C. Pellegrini et al., Nucl. Instr. and Meth. A 331 (1993) 223; H. Winick et al., Proc. IEEE 1993 Particle Accelerator Conf., Washington, DC, May 1993; C. Pellegrini, Nucl. Instr. and Meth. A 341 (1994) 326; J. Seeman, SPIE Meet. on Electron Beam Sources of High Brightness Radiation, San Diego, CA, July 1993 [1-4]); it would be a fourth-generation light source, with brightness, coherence, and peak power far exceeding other sources. Operating on the principle of the free electron laser (FEL), the LCLS would extend the range of FEL operation to much shorter wavelength than the 240 nm that has so far been reached. We report the results of studies of the use of the SLAC linac to drive an LCLS at wavelengths from about 3 to 100 nm initially and possibly even shorter wavelengths in the future. Lasing would be achieved in a single pass of a low emittance, high peak current, high-energy electron beam through a long undulator. Most present FELs use an optical cavity to build up the intensity of the light to achieve lasing action in a low-gain oscillator configuration. By eliminating the optical cavity, which is difficult to make at short wavelengths, laser action can be extended to shorter wavelengths by self-amplified-spontaneous-emission (SASE), or by harmonic generation from a longer wavelength seed laser. Short wavelength, single pass lasers have been extensively studied at several laboratories and at recent workshops (M. Cornacchia and H. Winick (eds.), SLAC Report 92/02; I. Ben-Zvi and H. Winick (eds.), BNL report 49651 [5,6]). The required low-emittance electron beam can be achieved with recently-developed rf photocathode electron guns (B.E. Carlsten, Nucl. Instr. and Meth. A 285 (1989) 313; J. Rosenzweig and L. Serafini, Proc. IEEE 1993 Particle Accelerator Conf., Washington, DC, 1993 [7,8]). The peak current is increased by about an

  10. Wakefields in SLAC linac collimators

    NASA Astrophysics Data System (ADS)

    Novokhatski, A.; Decker, F.-J.; Smith, H.; Sullivan, M.

    2014-12-01

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

  11. Reproduction of natural corrosion by accelerated laboratory testing methods

    SciTech Connect

    Luo, J.S.; Wronkiewicz, D.J.; Mazer, J.J.; Bates, J.K.

    1996-05-01

    Various laboratory corrosion tests have been developed to study the behavior of glass waste forms under conditions similar to those expected in an engineered repository. The data generated by laboratory experiments are useful for understanding corrosion mechanisms and for developing chemical models to predict the long-term behavior of glass. However, it is challenging to demonstrate that these test methods produce results that can be directly related to projecting the behavior of glass waste forms over time periods of thousands of years. One method to build confidence in the applicability of the test methods is to study the natural processes that have been taking place over very long periods in environments similar to those of the repository. In this paper, we discuss whether accelerated testing methods alter the fundamental mechanisms of glass corrosion by comparing the alteration patterns that occur in naturally altered glasses with those that occur in accelerated laboratory environments. This comparison is done by (1) describing the alteration of glasses reacted in nature over long periods of time and in accelerated laboratory environments and (2) establishing the reaction kinetics of naturally altered glass and laboratory reacted glass waste forms.

  12. SLAC Linear Collider

    SciTech Connect

    Richter, B.

    1985-12-01

    A report is given on the goals and progress of the SLAC Linear Collider. The status of the machine and the detectors are discussed and an overview is given of the physics which can be done at this new facility. Some ideas on how (and why) large linear colliders of the future should be built are given.

  13. The Brookhaven National Laboratory (BNL) Accelerator Test Facility

    SciTech Connect

    Batchelor, K.

    1990-01-01

    The design of the Brookhaven National Laboratory Accelerator Test Facility is presented including the design goals and computational results. The heart of the system is a radiofrequency electron gun utilizing a photo-excited metal cathode followed by a conventional electron linac. The Nd:YAG laser used to drive the cathode with 6 ps long pulses can be synchronized to a high peak power CO{sub 2} laser in order to study laser acceleration of electrons. Current operational status of the project will be presented along with early beam tests.

  14. Modeling laser-plasma acceleration in the laboratory frame

    SciTech Connect

    2011-01-01

    A simulation of laser-plasma acceleration in the laboratory frame. Both the laser and the wakefield buckets must be resolved over the entire domain of the plasma, requiring many cells and many time steps. While researchers often use a simulation window that moves with the pulse, this reduces only the multitude of cells, not the multitude of time steps. For an artistic impression of how to solve the simulation by using the boosted-frame method, watch the video "Modeling laser-plasma acceleration in the wakefield frame."

  15. Accelerator on a Chip

    SciTech Connect

    England, Joel

    2014-06-30

    SLAC's Joel England explains how the same fabrication techniques used for silicon computer microchips allowed their team to create the new laser-driven particle accelerator chips. (SLAC Multimedia Communications)

  16. Accelerator on a Chip

    ScienceCinema

    England, Joel

    2014-07-16

    SLAC's Joel England explains how the same fabrication techniques used for silicon computer microchips allowed their team to create the new laser-driven particle accelerator chips. (SLAC Multimedia Communications)

  17. Sleepless at SLAC

    SciTech Connect

    Dement, William

    2006-01-23

    Feeling tired? More than 30 million Americans suffer from sleep disorders. Nevertheless, as a society we remain largely ignorant of the significance of sleep in determining the quality of our waking lives. Dr. William Dement, Stanford Professor and one of the world's foremost experts on sleep and sleep deprivation, joins SLAC's Colloquium Series to present exciting new findings in the field of sleep research. You'll never sleep the same again!

  18. SLAC B Factory computing

    SciTech Connect

    Kunz, P.F.

    1992-02-01

    As part of the research and development program in preparation for a possible B Factory at SLAC, a group has been studying various aspects of HEP computing. In particular, the group is investigating the use of UNIX for all computing, from data acquisition, through analysis, and word processing. A summary of some of the results of this study will be given, along with some personal opinions on these topics.

  19. Felsenkeller shallow-underground accelerator laboratory for nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Bemmerer, D.; Cowan, T. E.; Gohl, S.; Ilgner, C.; Junghans, A. R.; Reinhardt, T. P.; Rimarzig, B.; Reinicke, S.; Röder, M.; Schmidt, K.; Schwengner, R.; Stöckel, K.; Szücs, T.; Takács, M.; Wagner, A.; Wagner, L.; Zuber, K.

    2015-05-01

    Favored by the low background in underground laboratories, low-background accelerator-based experiments are an important tool to study nuclear reactions involving stable charged particles. This technique has been used for many years with great success at the 0.4 MV LUNA accelerator in the Gran Sasso laboratory in Italy, proteced from cosmic rays by 1400 m of rock. However, the nuclear reactions of helium and carbon burning and the neutron source reactions for the astrophysical s-process require higher beam energies than those available at LUNA. Also the study of solar fusion reactions necessitates new data at higher energies. As a result, in the present NuPECC long range plan for nuclear physics in Europe, the installation of one or more higher-energy underground accelerators is strongly recommended. An intercomparison exercise has been carried out using the same HPGe detector in a typical nuclear astrophysics setup at several sites, including the Dresden Felsenkeller underground laboratory. It was found that its rock overburden of 45m rock, together with an active veto against the remaining muon flux, reduces the background to a level that is similar to the deep underground scenario. Based on this finding, a used 5 MV pelletron tandem with 250 μA upcharge current and external sputter ion source has been obtained and transported to Dresden. Work on an additional radio-frequency ion source on the high voltage terminal is underway. The project is now fully funded. The installation of the accelerator in the Felsenkeller is expected for the near future. The status of the project and the planned access possibilities for external users will be reported.

  20. Post-accelerator issues at the IsoSpin Laboratory

    SciTech Connect

    Chattopadhyay, S.; Nitschke, J.M.

    1994-05-01

    The workshop on ``Post-Accelerator Issues at the Isospin Laboratory`` was held at the Lawrence Berkeley Laboratory from October 27--29, 1993. It was sponsored by the Center for Beam Physics in the Accelerator and Fusion Research Division and the ISL Studies Group in the Nuclear Science Division. About forty scientists from around the world participated vigorously in this two and a half day workshop, (c.f. Agenda, Appendix D). Following various invited review talks from leading practitioners in the field on the first day, the workshop focussed around two working groups: (1) the Ion Source and Separators working group and (2) the Radio Frequency Quadrupoles and Linacs working group. The workshop closed with the two working groups summarizing and outlining the tasks for the future. This report documents the proceedings of the workshop and includes the invited review talks, the two summary talks from the working groups and individual contributions from the participants. It is a complete assemblage of state-of-the-art thinking on ion sources, low-{beta}, low(q/A) accelerating structures, e.g. linacs and RFQS, isobar separators, phase-space matching, cyclotrons, etc., as relevant to radioactive beam facilities and the IsoSpin Laboratory. We regret to say that while the fascinating topic of superconducting low-velocity accelerator structure was covered by Dr. K. Shepard during the workshop, we can only reproduce the copies of the transparencies of his talk in the Appendix, since no written manuscript was available at the time of publication of this report. The individual report have been catologed separately elsewhere.

  1. Radiation Dose Measurement for High-Intensity Laser Interactions with Solid Targets at SLAC

    SciTech Connect

    Liang, Taiee

    2015-09-25

    A systematic study of photon and neutron radiation doses generated in high-intensity laser-solid interactions is underway at SLAC National Accelerator Laboratory. We found that these laser-solid experiments are being performed using a 25 TW (up to 1 J in 40 fs) femtosecond pulsed Ti:sapphire laser at the Linac Coherent Light Source’s (LCLS) Matter in Extreme Conditions (MEC) facility. Additionally, radiation measurements were performed with passive and active detectors deployed at various locations inside and outside the target chamber. Results from radiation dose measurements for laser-solid experiments at SLAC MEC in 2014 with peak intensity between 1018 to 7.1x1019 W/cm2 are presented.

  2. An overview of the SLAC results

    SciTech Connect

    Prescott, C.Y.

    1996-03-01

    The history of nucleon spin-structure measurements goes back to the early days of inelastic electron scattering at SLAC, when Vernon Hughes came with a proposal to accelerate polarized electrons to high energy and to study inelastic scattering from a polarized proton target. The quark model of the proton was new at the time, and the spin-dependent structure functions were an excellent testing ground for that model. The proposal developed into an experiment which became SLAC experiment E80. Subsequent experiments followed those early studies, leading to E130 at SLAC, then EMC at CERN, and a host of later experiments. In 1988 the EMC Collaboration published the first data to reach low x. The asymmetries EMC observed fell below quark model expectations, and the experimentally measured proton sum rule indicated that the spin of the quarks contributed little to the proton spin. The subject of nucleon spin-dependent structure functions was stimulated by this surprising result from EMC. The continuation of the spin-structure studies at SLAC, which have been very active in recent years, was stimulated by the successful development of high-intensity beams of polarized electrons. Table 1 lists the past, present, and planned programs and experiments that grew out of the early work. The rest of the report is divided into the following topics: polarized electrons; polarimetry; the SLAC spectrometers; radiative corrections; the proton measurements; neutron targets; the deuterium and {sup 3}He data; the g{sub 2} structure function; and the 50 GeV upgrade of the SLC.

  3. Luminosity enhancements at SLAC

    SciTech Connect

    Coward, D.H.

    1984-04-01

    Several ideas are discussed that have been proposed to improve the luminosity at the SPEAR and PEP electron-positron storage rings and to insure good luminosity at the SLAC Linear Collider. There have been two proposals studied recently for SPEAR: a Microbeta insertion using Samarium Cobalt permanent magnets, and a Minibeta insertion using conventional quadrupole magnets. The notations Microbeta and minibeta used here are somewhat arbitrary since the front faces of the first quadrupole magnets for both insertions are at nearly the same distance from the interaction point.

  4. The SLAC Damped Detuned Structure: Concept and design

    SciTech Connect

    Kroll, N.M. |

    1997-05-01

    The SLAC Damped Detuned Structure (DDS) is an accelerator structure designed to suppress the long range transverse wakefields which limit the performance of high current multibunch accelerators. We discuss the conceptual considerations which have led to its development and discuss the steps involved in arriving at a design.

  5. A Look Inside SLAC's Battery Lab

    ScienceCinema

    Wei Seh, Zhi

    2014-07-21

    In this video, Stanford materials science and engineering graduate student Zhi Wei Seh shows how he prepares battery materials in SLAC's energy storage laboratory, assembles dime-sized prototype "coin cells" and then tests them to see how many charge-discharge cycles they can endure without losing their ability to hold a charge. Results to date have already set records: After 1,000 cycles, they retain 70 percent of their original charge.

  6. A Look Inside SLAC's Battery Lab

    SciTech Connect

    Wei Seh, Zhi

    2014-07-17

    In this video, Stanford materials science and engineering graduate student Zhi Wei Seh shows how he prepares battery materials in SLAC's energy storage laboratory, assembles dime-sized prototype "coin cells" and then tests them to see how many charge-discharge cycles they can endure without losing their ability to hold a charge. Results to date have already set records: After 1,000 cycles, they retain 70 percent of their original charge.

  7. The cyclotron laboratory and the RFQ accelerator in Bern

    SciTech Connect

    Braccini, S.; Ereditato, A.; Kreslo, I.; Nirkko, M.; Weber, M.; Scampoli, P.; Bremen, K. von

    2013-07-18

    Two proton accelerators have been recently put in operation in Bern: an 18 MeV cyclotron and a 2 MeV RFQ linac. The commercial IBA 18/18 cyclotron, equipped with a specifically conceived 6 m long external beam line ending in a separate bunker, will provide beams for routine 18-F and other PET radioisotope production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building hosting two physics laboratories and four Good Manufacturing Practice (GMP) laboratories. This project is the result of a successful collaboration between the Inselspital, the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. The cyclotron is complemented by the RFQ with the primary goals of elemental analysis via Particle Induced Gamma Emission (PIGE), and the detection of potentially dangerous materials with high nitrogen content using the Gamma-Resonant Nuclear Absorption (GRNA) technique. In this context, beam instrumentation devices have been developed, in particular an innovative beam profile monitor based on doped silica fibres and a setup for emittance measurements using the pepper-pot technique. On this basis, the establishment of a proton therapy centre on the campus of the Inselspital is in the phase of advanced study.

  8. The cyclotron laboratory and the RFQ accelerator in Bern

    NASA Astrophysics Data System (ADS)

    Braccini, S.; Ereditato, A.; Kreslo, I.; Nirkko, M.; Scampoli, P.; von Bremen, K.; Weber, M.

    2013-07-01

    Two proton accelerators have been recently put in operation in Bern: an 18 MeV cyclotron and a 2 MeV RFQ linac. The commercial IBA 18/18 cyclotron, equipped with a specifically conceived 6 m long external beam line ending in a separate bunker, will provide beams for routine 18-F and other PET radioisotope production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building hosting two physics laboratories and four Good Manufacturing Practice (GMP) laboratories. This project is the result of a successful collaboration between the Inselspital, the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. The cyclotron is complemented by the RFQ with the primary goals of elemental analysis via Particle Induced Gamma Emission (PIGE), and the detection of potentially dangerous materials with high nitrogen content using the Gamma-Resonant Nuclear Absorption (GRNA) technique. In this context, beam instrumentation devices have been developed, in particular an innovative beam profile monitor based on doped silica fibres and a setup for emittance measurements using the pepper-pot technique. On this basis, the establishment of a proton therapy centre on the campus of the Inselspital is in the phase of advanced study.

  9. PREFACE: Acceleration and radiation generation in space and laboratory plasmas

    NASA Astrophysics Data System (ADS)

    Bingham, R.; Katsouleas, T.; Dawson, J. M.; Stenflo, L.

    1994-01-01

    Sixty-six leading researchers from ten nations gathered in the Homeric village of Kardamyli, on the southern coast of mainland Greece, from August 29-September 4, 1993 for the International Workshop on Acceleration and Radiation Generation in Space and Laboratory Plasmas. This Special Issue represents a cross-section of the presentations made at and the research stimulated by that meeting. According to the Iliad, King Agamemnon used Kardamyli as a dowry offering in order to draw a sulking Achilles into the Trojan War. 3000 years later, Kardamyli is no less seductive. Its remoteness and tranquility made it an ideal venue for promoting the free exchange of ideas between various disciplines that do not normally interact. Through invited presen tations, informal poster discussions and working group sessions, the Workshop brought together leaders from the laboratory and space/astrophysics communities working on common problems of acceleration and radiation generation in plasmas. It was clear from the presentation and discussion sessions that there is a great deal of common ground between these disciplines which is not at first obvious due to the differing terminologies and types of observations available to each community. All of the papers in this Special Issue highlight the role collective plasma processes play in accelerating particles or generating radiation. Some are state-of-the-art presentations of the latest research in a single discipline, while others investi gate the applicability of known laboratory mechanisms to explain observations in natural plasmas. Notable among the latter are the papers by Marshall et al. on kHz radiation in the magnetosphere ; Barletta et al. on collective acceleration in solar flares; and by Dendy et al. on ion cyclotron emission. The papers in this Issue are organized as follows: In Section 1 are four general papers by Dawson, Galeev, Bingham et al. and Mon which serves as an introduction to the physical mechanisms of acceleration

  10. Laser Safety for the Experimental Halls at SLAC_s Linac Coherent Light Source (LCLS)

    SciTech Connect

    Woods, Michael; Anthony, Perry; Barat, Ken; Gilevich, Sasha; Hays, Greg; White, William E.; /SLAC

    2009-01-15

    The LCLS at the SLAC National Accelerator Laboratory will be the world's first source of an intense hard x-ray laser beam, generating x-rays with wavelengths of 1nm and pulse durations less than 100fs. The ultrafast x-ray pulses will be used in pump-probe experiments to take stop-motion pictures of atoms and molecules in motion, with pulses powerful enough to take diffraction images of single molecules, enabling scientists to elucidate fundamental processes of chemistry and biology. Ultrafast conventional lasers will be used as the pump. In 2009, LCLS will deliver beam to the Atomic Molecular and Optical (AMO) Experiment, located in one of 3 x-ray Hutches in the Near Experimental Hall (NEH). The NEH includes a centralized Laser Hall, containing up to three Class 4 laser systems, three x-ray Hutches for experiments and vacuum transport tubes for delivering laser beams to the Hutches. The main components of the NEH laser systems are a Ti:sapphire oscillator, a regen amplifier, green pump lasers for the oscillator and regen, a pulse compressor and a harmonics conversion unit. Laser safety considerations and controls for the ultrafast laser beams, multiple laser controlled areas, and user facility issues are discussed.

  11. Environmental Survey preliminary report, Fermi National Accelerator Laboratory, Batavia, Illinois

    SciTech Connect

    Not Available

    1988-10-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the US Department of Energy (DOE) Fermi National Accelerator Laboratory (Fermilab), conducted September 14 through 25, 1987. The Survey is being conducted by an interdisciplinary team of environmental specialists led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual participants for the Survey team are being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with Fermilab. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations performed at Fermilab, and interviews with site personnel. 110 refs., 26 figs., 41 tabs.

  12. Los Alamos National Laboratory accelerated tru waste workoff strategies

    SciTech Connect

    Kosiewicz, S.T.; Triay, I.R.; Rogers, P.Z.; Christensen, D.V.

    1997-03-01

    During 1996, the Los Alamos National Laboratory (LANL) developed two transuranic (TRU) waste workoff strategies that were estimated to save $270 - 340M through accelerated waste workoff and the elimination of a facility. The planning effort included a strategy to assure that LANL would have a significant quantity (3000+ drums) of TRU waste certified for shipment to the Waste Isolation Pilot Plant (WIPP) beginning in April of 1998, when WIPP was projected to open. One of the accelerated strategies can be completed in less than ten years through a Total Optimization of Parameters Scenario ({open_quotes}TOPS{close_quotes}). {open_quotes}TOPS{close_quotes} fully utilizes existing LANL facilities and capabilities. For this scenario, funding was estimated to be unconstrained at $23M annually to certify and ship the legacy inventory of TRU waste at LANL. With {open_quotes}TOPS{close_quotes} the inventory is worked off in about 8.5 years while shipping 5,000 drums per year at a total cost of $196M. This workoff includes retrieval from earthen cover and interim storage costs. The other scenario envisioned funding at the current level with some increase for TRUPACT II loading costs, which total $16M annually. At this funding level, LANL estimates it will require about 17 years to work off the LANL TRU legacy waste while shipping 2,500 drums per year to WIPP. The total cost will be $277M. This latter scenario decreases the time for workoff by about 19 years from previous estimates and saves an estimated $190M. In addition, the planning showed that a $70M facility for TRU waste characterization was not needed. After the first draft of the LANL strategies was written, Congress amended the WIPP Land Withdrawal Act (LWA) to accelerate the opening of WIPP to November 1997. Further, the No Migration Variance requirement for the WIPP was removed. This paper discusses the LANL strategies as they were originally developed. 1 ref., 3 figs., 2 tabs.

  13. Tiger Team Assessment of the Fermi National Accelerator Laboratory

    SciTech Connect

    Not Available

    1992-06-01

    This draft report documents the Tiger Team Assessment of the Fermi National Accelerator Laboratory (Fermilab) located in Batavia, Illinois. Fermilab is a program-dedicated national laboratory managed by the Universities Research Association, Inc. (URA) for the US Department of Energy (DOE). The Tiger Team Assessment was conducted from May 11 to June 8, 1992, under the auspices of DOE's Office of Special Projects (OSP) under the Office of the Assistant Secretary for Environment, Safety and Health (EH). The assessment was comprehensive, encompassing environmental, safety and health (ES H), and quality assurance (QA) disciplines; site remediation; facilities management; and waste management operations. Compliance with applicable Federal , State of Illinois, and local regulations; applicable DOE Orders; best management practices; and internal Fermilab requirements was addressed. In addition, an evaluation of the effectiveness of DOE and Fermilab management of the ES H/QA and self-assessment programs was conducted. The Fermilab Tiger Team Assessment is part a larger, comprehensive DOE Tiger Team Independent Assessment Program planned for DOE facilities. The objective of the initiative is to provide the Secretary of Energy with information on the compliance status of DOE facilities with regard to ES H requirements, root causes for noncompliance, adequacy of DOE and contractor ES H management programs, response actions to address the identified problem areas, and DOE-wide ES H compliance trends and root causes.

  14. Tiger Team Assessment of the Fermi National Accelerator Laboratory

    SciTech Connect

    Not Available

    1992-06-01

    This draft report documents the Tiger Team Assessment of the Fermi National Accelerator Laboratory (Fermilab) located in Batavia, Illinois. Fermilab is a program-dedicated national laboratory managed by the Universities Research Association, Inc. (URA) for the US Department of Energy (DOE). The Tiger Team Assessment was conducted from May 11 to June 8, 1992, under the auspices of DOE`s Office of Special Projects (OSP) under the Office of the Assistant Secretary for Environment, Safety and Health (EH). The assessment was comprehensive, encompassing environmental, safety and health (ES&H), and quality assurance (QA) disciplines; site remediation; facilities management; and waste management operations. Compliance with applicable Federal , State of Illinois, and local regulations; applicable DOE Orders; best management practices; and internal Fermilab requirements was addressed. In addition, an evaluation of the effectiveness of DOE and Fermilab management of the ES&H/QA and self-assessment programs was conducted. The Fermilab Tiger Team Assessment is part a larger, comprehensive DOE Tiger Team Independent Assessment Program planned for DOE facilities. The objective of the initiative is to provide the Secretary of Energy with information on the compliance status of DOE facilities with regard to ES&H requirements, root causes for noncompliance, adequacy of DOE and contractor ES&H management programs, response actions to address the identified problem areas, and DOE-wide ES&H compliance trends and root causes.

  15. Tiger Team Assessment of the Stanford Linear Accelerator Center

    SciTech Connect

    Not Available

    1991-11-01

    This report documents the Tiger Team Assessment of the buildings, facilities, and activities at the Stanford Linear Accelerator Center (SLAC) and the Stanford Synchrotron Radiation Laboratory (SSRL) near San Francisco, California. SLAC/SSRL is the twenty-eighth DOE site to be assessed by a Tiger Team. SLAC and SSRL are single-purpose laboratories. SLAC is dedicated to experimental and theoretical research in elementary particle physics and to the development of new techniques in high-energy accelerators and elementary particle detectors. SSRL is dedicated to research in atomic and solid-state physics, chemistry, biology, and medicine. The purpose of the SLAC/SSRL Tiger Team Assessment is to provide the Secretary of Energy with concise information on the following: current ES H compliance status at the site and the vulnerabilities associated with that compliance status; root causes for noncompliance; adequacy of DOE and SLAC/SSRL ES H management programs; response actions to address identified problem areas; and effectiveness of self-assessment.

  16. Tiger Team Assessment of the Stanford Linear Accelerator Center

    SciTech Connect

    Not Available

    1991-11-01

    This report documents the Tiger Team Assessment of the buildings, facilities, and activities at the Stanford Linear Accelerator Center (SLAC) and the Stanford Synchrotron Radiation Laboratory (SSRL) near San Francisco, California. SLAC/SSRL is the twenty-eighth DOE site to be assessed by a Tiger Team. SLAC and SSRL are single-purpose laboratories. SLAC is dedicated to experimental and theoretical research in elementary particle physics and to the development of new techniques in high-energy accelerators and elementary particle detectors. SSRL is dedicated to research in atomic and solid-state physics, chemistry, biology, and medicine. The purpose of the SLAC/SSRL Tiger Team Assessment is to provide the Secretary of Energy with concise information on the following: current ES&H compliance status at the site and the vulnerabilities associated with that compliance status; root causes for noncompliance; adequacy of DOE and SLAC/SSRL ES&H management programs; response actions to address identified problem areas; and effectiveness of self-assessment.

  17. Laboratory Simulation of Ion Acceleration Mechanisms in the Suprauroral Region.

    NASA Astrophysics Data System (ADS)

    Koslover, Robert Avner

    1987-09-01

    We report the results of a series of laboratory experiments intended to simulate particular aspects of ion acceleration processes that have been observed or are believed to occur in the suprauroral region of the Earth's magnetosphere. Beam-generated lower hybrid waves (LHW) and current-driven electrostatic ion cyclotron waves (EICW) have both been proposed as responsible for low-altitude perpendicular ion acceleration, leading to the formation of ion conics at higher altitudes (after mirroring in the geomagnetic field). We model, by experiments in the laboratory, the mechanisms generating the ion velocity distributions and radio frequency waves observed in the suprauroral region. Experiments were performed in two linear plasma devices: the UCI Q -machine and UCI Magnetic Mirror. RF waves were launched by antennas or excited by electron currents or beams. Laser induced fluorescence (LIF) provided a sensitive non-perturbing diagnostic for ion velocity distributions. RF and Langmuir probes were used for electrical measurements. Antenna launched LHW produced considerable perpendicular ion heating, generating 'tail' formation followed by a bulk 'maxwellian' heating. Both broadband and narrowband LHW produced similar effects. Frequency spectra displayed multiple harmonics of the input antenna signal and also signals of lower frequency, the latter identified as due to parametric decay. Operating the UCI Magnetic Mirror as a double plasma device, a low energy, low density electron beam was shown to generate very broadband noise above the LH resonance frequency. Two-probe correlation studies indicated the existence of a wide band of k values as well. The noise has been tentatively identified as beam-generated LHW. In order to study the formation of ion conics, a new diagnostic method making use of LIF and computed tomography was developed. A description is given of this new technique, which we call optical tomography. Using this approach, we successfully observed the

  18. Laboratory test of Newton's second law for small accelerations.

    PubMed

    Gundlach, J H; Schlamminger, S; Spitzer, C D; Choi, K-Y; Woodahl, B A; Coy, J J; Fischbach, E

    2007-04-13

    We have tested the proportionality of force and acceleration in Newton's second law, F=ma, in the limit of small forces and accelerations. Our tests reach well below the acceleration scales relevant to understanding several current astrophysical puzzles such as the flatness of galactic rotation curves, the Pioneer anomaly, and the Hubble acceleration. We find good agreement with Newton's second law at accelerations as small as 5 x 10(-14) m/s(2). PMID:17501332

  19. Laboratory Test of Newton's Second Law for Small Accelerations

    SciTech Connect

    Gundlach, J. H.; Schlamminger, S.; Spitzer, C. D.; Choi, K.-Y.; Woodahl, B. A.; Coy, J. J.; Fischbach, E.

    2007-04-13

    We have tested the proportionality of force and acceleration in Newton's second law, F=ma, in the limit of small forces and accelerations. Our tests reach well below the acceleration scales relevant to understanding several current astrophysical puzzles such as the flatness of galactic rotation curves, the Pioneer anomaly, and the Hubble acceleration. We find good agreement with Newton's second law at accelerations as small as 5x10{sup -14} m/s{sup 2}.

  20. SLAC linear collider: the machine, the physics, and the future

    SciTech Connect

    Richter, B.

    1981-11-01

    The SLAC linear collider, in which beams of electrons and positrons are accelerated simultaneously, is described. Specifications of the proposed system are given, with calculated preditions of performance. New areas of research made possible by energies in the TeV range are discussed. (GHT)

  1. SLAC pulsed x-ray facility

    SciTech Connect

    Ipe, N.E.; McCall, R.C.; Baker, E.D.

    1986-05-01

    The Stanford Linear Accelerator Center (SLAC) operates a high energy (up to 33 GeV) linear accelerator delivering pulses up to a few microseconds wide. The pulsed nature of the electron beam creates problems in the detection and measurement of radiation both from the accelerator beam and the klystrons that provide the rf power for the accelerator. Hence, a pulsed x-ray facility has been built at SLAC mainly for the purpose of testing the response of different radiation detection instruments to pulsed radiation fields. The x-ray tube consists of an electron gun with a control grid. This provides a stream of pulsed electrons that can be accelerated towards a confined target-window. The window is made up of aluminium 0.051 cm (20 mils) thick, plated on the vacuum side with a layer of gold 0.0006 cm (1/4 mil) thick. The frequency of electron pulses can be varied by an internal pulser from 60 to 360 pulses per second with pulse widths of 360 ns to 5 ..mu..s. The pulse amplitude can be varied over a wide range of currents. An external pulser can be used to obtain other frequencies or special pulse shapes. The voltage across the gun can be varied from 0 to 100 kV. The major part of the x-ray tube is enclosed in a large walk-in-cabinet made of 1.9 cm (3/4 in) plywood and lined with 0.32 cm (1/8 in) lead to make a very versatile facility. 3 refs., 5 figs.

  2. SLAC pulsed X-ray facility

    NASA Astrophysics Data System (ADS)

    Ipe, N. E.; McCall, R. C.; Baker, E. D.

    1986-05-01

    The Stanford Linear Accelerator Center (SLAC) operates a high energy (up to 33 GeV) linear accelerator delivering pulses up to a few microseconds wide. The pulsed nature of the electron beam creates problems in the detection and measurement of radiation both from the accelerator beam and the klystrons that provide the RF power for the accelerator. Hence, a pulsed X-ray facility has been built at SLAC mainly for the purpose of testing the response of different radiation detection instruments to pulsed radiation fields. The X-ray tube consists of an electron gun with a control grid. This provides a stream of pulsed electrons that can be accelerated towards a confined target-window. The window is made up of aluminum 0.051 cm (20 mils) thick, plated on the vacuum side with a layer of gold 0.0006 cm (1/4 mil) thick. The frequency of electron pulses can be varied by an internal pulser from 60 to 360 pulses per second with pulse widths of 360 ns to 5 ms. The pulse amplitude can be varied over a wide range of currents. An external pulser can be used to obtain other frequencies or special pulse shapes. The voltage across the gun can be varied from 0 to 100 kV. The major part of the X-ray tube is enclosed in a large walk-in-cabinet made of 1.9 cm (3/4 in) plywood and lined with 0.32 cm (1/8 in) lead to make a very versatile facility.

  3. A Solid State Modulator for Driving SLAC 5045 Klystrons

    SciTech Connect

    Lamare, Jeffrey E

    2002-09-19

    A test is ongoing at the Stanford Linear Accelerator Center (SLAC) where a solid state induction modulator is driving a SLAC 5045 klystron. The modulator generates 22 kV, 6 kA pulses that are stepped up by a 15.1 transformer that is a part of the klystron's pulse tank. The modulator's pulse duration is adjustable up to the volt-second limit of its cores, and it is capable of a pulse repetition frequency up to 120 Hz. The modulator's design, construction, and experimental results are the focus of this paper.

  4. Dust accelerator tests of the LDEX laboratory model

    NASA Astrophysics Data System (ADS)

    Li, Y. W.; Bugiel, S.; Hofmann, B.; Horanyi, M.; Sternovsky, Z.; Srama, R.

    2015-10-01

    The LDEX (Lunar Dust EXperiment) sensor onboard lunar orbiter LADEE (Lunar Atmosphere and Dust Environment Explorer) was designed to characterize the size and spatial distributions of micron and sub-micron sized dust grains. Recent results of the data analysis showed strong evidence for the existence of a dust cloud around the moon. LDEX performs in situ measurements of dust impacts along the LADEE or-bit. The impact speed of the observed dust grains is close to 1.7 km/s (the speed of the spacecraft), since the dust grains are considered on bound orbits close to the maximum height of their ballistic motion. LDEX is an impact ionization dust detector for in situ measurements. The detection of a dust grains is based on measuring the charge generated by high speed impacts (>1km/s) on a rhodium coated target. The impact charge Q is a function of both the speed v and the mass m of the impacting dust particle. The characteristic values are dependent on the instrument geometry, the impact surface properties (material), the impact geometry (impact angle) and the particle properties (material, density, speed, mass, shape). In our tests we used PPy-coated olivine and PPy-coated ortho-pyroxene with impact speeds around 1.7 km/s. A LDEX laboratory model was designed and manufactured by the University of Stuttgart. The model is used to support calibration activities of the Univ. of Colorado and to perform special tests (impact angle and impact location variations) at the dust accelerator facility at MPI-K (Heidelberg) which is operated by the IRS of the University of Stuttgart.

  5. SLAC Cosmic Ray Telescope Facility

    SciTech Connect

    Va'vra, J.

    2010-02-15

    SLAC does not have a test beam for the HEP detector development at present. We have therefore created a cosmic ray telescope (CRT) facility, which is presently being used to test the FDIRC prototype. We have used it in the past to debug this prototype with the original SLAC electronics before going to the ESA test beam. Presently, it is used to test a new waveform digitizing electronics developed by the University of Hawaii, and we are also planning to incorporate the new Orsay TDC/ADC electronics. As a next step, we plan to put in a full size DIRC bar box with a new focusing optics, and test it together with a final SuberB electronics. The CRT is located in building 121 at SLAC. We anticipate more users to join in the future. This purpose of this note is to provide an introductory manual for newcomers.

  6. Vacuum Systems Consensus Guideline for Department of Energy Accelerator Laboratories

    SciTech Connect

    Casey,R.; Haas, E.; Hseuh, H-C.; Kane, S.; Lessard, E.; Sharma, S.; Collins, J.; Toter, W. F.; Olis, D. R.; Pushka, D. R.; Ladd, P.; Jobe, R. K.

    2008-09-09

    inspections of materials, in-process fabrications, non-destructive tests, and acceptance test. (3) Documentation, traceability, and accountability must be maintained for each unique pressure vessel or system, including descriptions of design, pressure conditions, testing, inspection, operation, repair, and maintenance. The purpose of this guideline is to establish a set of expectations and recommendations which will satisfy the requirements for vacuum vessels in general and particularly when an equivalent level of safety as required by 10 CFR 851 must be provided. It should be noted that these guidelines are not binding on DOE Accelerator Laboratories and that other approaches may be equally acceptable in addressing the Part 851 requirements.

  7. Status of the SLAC Linear Collider Project

    SciTech Connect

    Stiening, R.

    1983-01-01

    The SLAC Linear Collider Project has two principal goals. The first is to serve as a prototype for a future very high energy linear electron-positron collider. The second is to quickly, at low cost, achieve sufficient luminosity at 100 GeV center-of-mass energy to explore the physics of the Z/sup 0/. The first goal is important to the future of electron-positron physics because the rapid increase of synchrotron radiation with energy causes the cost of circular storage ring colliders to whereas the cost of linear colliders increases only in proportion to the center-of-mass energy. The second is important because the existance at SLAC of a linear accelerator which can be converted at low cost to collider operation makes possible a unique opportunity to quickly achieve 100 GeV center-of-mass collisions. At the design luminosity of 6.0 x 10/sup 30/ many thousands of Z/sup 0/ decays should be observed in each day of operation.

  8. Network resource and applications management at SLAC

    SciTech Connect

    Logg, C.A.; Cottrell, R.L.A.

    1996-02-01

    The Stanford Linear Accelerator Center (SLAC) has a heterogeneous networked computing environment with a variety of transmission media, protocols, equipment from multiple vendors, Local Areas Network (LAN) and Wide Area Network (WAN) connections, workstations, servers, legacy mainframes, operating systems, network services and applications, and users of various skill levels. New technologies are continually being deployed as they become available. All of these components work together (most of the time) but result in a complex distributed computing environment (henceforth referred to as the system) which requires automated monitoring and management for the maintenance of high quality performance with limited personnel and budgets. There is no Network Management Station (NMS) product which comes close to doing the job of monitoring and managing the LAN and WAN for SLAC. However, by making use of Ping, Simple Network Management Protocol (SNMP) and its Management Information Bases (MIBs), as well as network applications (trace-route, File Transfer Protocol (FTP), Remote Procedure Calls (RPCs), Remote Shell (rsh), et.al.), an NMS (Netview for AIX), and the accounting and monitoring facilities provided by the server operating systems, the challenge is surmountable.

  9. Binary rf pulse compression experiment at SLAC

    SciTech Connect

    Lavine, T.L.; Spalek, G.; Farkas, Z.D.; Menegat, A.; Miller, R.H.; Nantista, C.; Wilson, P.B.

    1990-06-01

    Using rf pulse compression it will be possible to boost the 50- to 100-MW output expected from high-power microwave tubes operating in the 10- to 20-GHz frequency range, to the 300- to 1000-MW level required by the next generation of high-gradient linacs for linear for linear colliders. A high-power X-band three-stage binary rf pulse compressor has been implemented and operated at the Stanford Linear Accelerator Center (SLAC). In each of three successive stages, the rf pulse-length is compressed by half, and the peak power is approximately doubled. The experimental results presented here have been obtained at low-power (1-kW) and high-power (15-MW) input levels in initial testing with a TWT and a klystron. Rf pulses initially 770 nsec long have been compressed to 60 nsec. Peak power gains of 1.8 per stage, and 5.5 for three stages, have been measured. This corresponds to a peak power compression efficiency of about 90% per stage, or about 70% for three stages, consistent with the individual component losses. The principle of operation of a binary pulse compressor (BPC) is described in detail elsewhere. We recently have implemented and operated at SLAC a high-power (high-vacuum) three-stage X-band BPC. First results from the high-power three-stage BPC experiment are reported here.

  10. Wake fields in SLAC Linac Collimators

    SciTech Connect

    Novokhatski, Alexander; Decker, F. -J.; Smith, H.; Sullivan, M.

    2014-12-02

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

  11. Accelerating Particles with Plasma

    SciTech Connect

    Litos, Michael; Hogan, Mark

    2014-11-05

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  12. Pulsed rf superconductivity program at SLAC

    SciTech Connect

    Campisi, I.E.; Farkas, Z.D.

    1984-08-01

    Recent tests performed at SLAC on superconducting TM/sub 010/ caavities using short rf pulses (less than or equal to 2.5 ..mu..s) have established that at the cavity surface magnetic fields can be reached in the vicinity of the theoretical critical fields without an appreciable increase in average losses. Tests on niobium and lead cavities are reported. The pulse method seems to be best suited to study peak field properties of superconductors in the microwave band, without the limitations imposed by defects. The short pulses also seem to be more effective in decreasing the causes of field emission by rf processing. Applications of the pulsed rf superconductivity to high-gradient linear accelerators are also possible.

  13. Numerical Investigation and Experimental Reproduction of Fermi Acceleration in Laboratory Scale

    NASA Astrophysics Data System (ADS)

    Zhou, M.; Zhai, C.

    2015-12-01

    Fermi acceleration is widely accepted as the mechanism to explain power law of cosmic ray spectrum. Now this mechanism has been developed to first order Fermi acceleration and second order Fermi acceleration. In first order Fermi acceleration, also known as diffusive shock acceleration, particles are confined around the shock through scattering and accelerated by repeatedly crossing shock front. In second order Fermi acceleration, particles gain energy through statistical collisions with interstellar clouds. In this proposed work, we plan to carefully study these two kinds of acceleration numerically and experimentally. We first consider a single relativistic particle and investigate how it gains energy in Fermi-Ulam model and shock wave acceleration model respectively. We investigate collective behavior of particles with different kinds of wall-oscillation functions and try to find an optimal one in terms of efficiency of acceleration. Then, we plan to go further and consider a group of particles statistically, during which we borrow the correct generalization of Maxwell's velocity distribution in special relativity and compare the results with those in cases where we simply use Maxwell-Boltzmann distribution. To this end, we try to provide a scheme to build an accelerator applying both laser technology and mirror effect in Laboratory to reproduce Fermi acceleration, which might be a promising source to obtain high energy particles and further study the mechanism of cosmic rays acceleration.

  14. Documenting the Physical Universe:Preserving the Record of SLAC from 1962 to 2005

    SciTech Connect

    Deken, Jean Marie; /SLAC

    2006-03-10

    Since 1905, Albert Einstein's ''miraculous year'', modern physics has advanced explosively. In 2005, the World Year of Physics, a session at the SAA Annual meeting discusses three institutional initiatives--Einstein's collected papers, an international geophysical program, and a research laboratory--to examine how physics and physicists are documented and how that documentation is being collected, preserved, and used. This paper provides a brief introduction to the research laboratory (SLAC), discusses the origins of the SLAC Archives and History Office, its present-day operations, and the present and future challenges it faces in attempting to preserve an accurate historical record of SLAC's activities.

  15. GLAST beam test at SLAC

    SciTech Connect

    Engovatov, D.; Anthony, P.; Atwood, W.

    1996-10-01

    In May and June, a beam test for GLAST calorimeter technologies was conducted. A parasitic low intensity electron/tagged photon beam line into the End Station A at SLAC was commissioned and used. The preliminary stage of the test was devoted to measuring the performance of the parasitic beam. In the main test we studied the response of GLAST prototype CsI and scintillating fiber calorimeters to the electrons and photons. Results of this work are discussed.

  16. Recent GPS Results at SLAC

    SciTech Connect

    Behrend, Dirk; Imfeld, Hans L.; /SLAC

    2005-08-17

    The Alignment Engineering Group (AEG) makes use of GPS technology for fulfilling part of its above ground surveying tasks at SLAC since early 2002. A base station (SLAC M40) has been set up at a central location of the SLAC campus serving both as master station for real-time kinematic (RTK) operations and as datum point for local GPS campaigns. The Leica RS500 system is running continuously and the GPS data are collected both externally (logging PC) and internally (receiver flashcard). The external logging is facilitated by a serial to Ethernet converter and an Ethernet connection at the station. Internal logging (ring buffer) is done for data security purposes. The weatherproof boxes for the instrumentation are excellent shelters against rain and wind, but do heat up considerably in sun light. Whereas the GPS receiver showed no problems, the Pacific Crest PDL 35 radio shut down several times due to overheating disrupting the RTK operations. In order to prevent heat-induced shutdowns, a protection against direct sun exposure (shading) and a constant air circulation system (ventilation) were installed. As no further shutdowns have occurred so far, it appears that the two measures successfully mended the heat problem.

  17. Preliminary results of the echo-seeding experiment at SLAC

    SciTech Connect

    Xiang, D.; Colby, E.; Ding, Y.; Dunning, M.; Frederico, J.; Gilevich, S.; Hast, C.; Jobe, K.; McCormick, D.; Nelson, J.; Raubenheimer, T.O.; Soong, K.; Stupakov, G.; Szalata, Z.; Walz, D.; Weathersby, S.; Woodley, M.; Corlett, J.; Qiang, J.; Penn, G.; Prestemon, S.; Schlueter, R.; Venturini, M.; Wan, W.; Pernet, P-L.

    2010-05-23

    ECHO-7 is a proof-of-principle echo-enabled harmonic generation FEL experiment in the Next Linear Collider Test Accelerator (NLCTA) at SLAC. The experiment aims to generate coherent radiation at 318 nm and 227 nm, which are the 5th and 7th harmonic of the infrared seed laser. In this paper we present the preliminary results from the commissioning run of the completed experimental setup which started in April 2010.

  18. Review of trigger and on-line processors at SLAC

    SciTech Connect

    Lankford, A.J.

    1984-07-01

    The role of trigger and on-line processors in reducing data rates to manageable proportions in e/sup +/e/sup -/ physics experiments is defined not by high physics or background rates, but by the large event sizes of the general-purpose detectors employed. The rate of e/sup +/e/sup -/ annihilation is low, and backgrounds are not high; yet the number of physics processes which can be studied is vast and varied. This paper begins by briefly describing the role of trigger processors in the e/sup +/e/sup -/ context. The usual flow of the trigger decision process is illustrated with selected examples of SLAC trigger processing. The features are mentioned of triggering at the SLC and the trigger processing plans of the two SLC detectors: The Mark II and the SLD. The most common on-line processors at SLAC, the BADC, the SLAC Scanner Processor, the SLAC FASTBUS Controller, and the VAX CAMAC Channel, are discussed. Uses of the 168/E, 3081/E, and FASTBUS VAX processors are mentioned. The manner in which these processors are interfaced and the function they serve on line is described. Finally, the accelerator control system for the SLC is outlined. This paper is a survey in nature, and hence, relies heavily upon references to previous publications for detailed description of work mentioned here. 27 references, 9 figures, 1 table.

  19. Implementation of the beamline controls at the Florence accelerator laboratory

    NASA Astrophysics Data System (ADS)

    Carraresi, L.; Mirto, F. A.

    2008-05-01

    The new Tandetron accelerator in Florence, with many different beamlines, has required a new organization of all the control signals of the used equipment (slow control). We present our solution, which allows us the control of all the employed instruments simultaneously from a number of different workplaces. All of our equipment has been designed to be Ethernet based and this is the key to accomplish two very important requirements: simultaneous remote control from many computers and electrical isolation to achieve a lower noise level. The control of the instruments requires only one Ethernet network and no particular interfaces or drivers on the computers.

  20. Fermi National Accelerator Laboratory Annual Program Review 1991

    SciTech Connect

    Appel, Jeffrey A.; Jovanovic, Drasko; Pordes, Stephen

    1991-01-01

    This book is submitted as a written adjunct to the Annual DOE High Energy Physics Program Review of Fermilab, scheduled this year for April 10-12, 1991. In it are described the functions and activities of the various Laboratory areas plus statements of plans and goals for the coming year.

  1. Fermi National Accelerator Laboratory Annual Program Review 1993

    SciTech Connect

    1993-01-01

    This book is submitted as a written adjunct to the 1993 Annual DOE High Energy Physics Program Review of Fermilab, scheduled for March 31-April 3. In it are described the functions and activities of the various Laboratory Divisions and Sections plus statements of plans and goals for the coming year. The Review Committee, as this goes to press, consists of·

  2. Fermi National Accelerator Laboratory Annual Program Review 2000

    SciTech Connect

    2000-03-01

    This book is submitted as one written part of the 2000 Annual DOE High Energy Physics Program Review of Fermilab, scheduled March 22-24, 2000. In it are Director's Overview, some experimental highlights, discussions of several projects, and descriptions of the functions and activities of the four laboratory divisions. This book should be read in conjunction with the 2000 Fermilab Workbook and the review presentations (both in formal sessions and at the poster session).

  3. Chemical depth profiling of photovoltaic backsheets after accelerated laboratory weathering

    NASA Astrophysics Data System (ADS)

    Lin, Chiao-Chi; Krommenhoek, Peter J.; Watson, Stephanie S.; Gu, Xiaohong

    2014-10-01

    Polymeric multilayer backsheets provide protection for the backside of photovoltaic (PV) module from the damage of moisture and ultraviolet (UV). Due to the nature of multilayer films, certain material property characterization of a backsheet could only be studied by examining its cross-section parallel to the thickness direction of the film. In this study, commercial PPE (polyethylene terephthalate (PET)/PET/ethylene vinyl acetate (EVA)) backsheet films were aged on the NIST (National Institute of Standards and Technology) SPHERE (Simulated Photodegradation via High Energy Radiant Exposure) with UV irradiance at 170 W/m2 (300 nm to 400 nm) under accelerated weathering conditions of 85°C and two relative humidity (R.H.) levels of 5% (low) and 60% (high). Cryo-microtomy was used to obtain cross-sectional PPE samples with a flat surface parallel to the thickness direction, and chemical depth profiling of multilayers was conducted by Raman microscopic mapping. Atomic force microscopy with peak force tapping mode was used complementarily for cross-sectional imaging. The results revealed that the PPE backsheet films were comprised of five main layers, including pigmented-PET, core PET, inner EVA, pigmented-EVA and outer EVA, along with their interfacial regions and two adhesive layers. UV and moisture degradation on the outer pigmented PET layer was clearly observed; while the damage on the core PET layer was less significance, indicating that the outer pigmented PET layer effectively reduced the damage from UV. In high R.H. exposure, both adhesive layers were severely deteriorated. It was found that the EVA layers were susceptible to moisture at elevated temperature, especially for the pigmented-EVA. Based on the results of accelerated weathering, this depth profiling study brings new understanding to the mechanisms of failure observed in polymeric multilayer backsheets during field exposure.

  4. The SLAC polarized electron source

    SciTech Connect

    Tang, H.; Alley, R.; Frisch, J.

    1995-06-01

    The SLAC polarized electron source employs a photocathode DC high voltage gun with a loadlock and a YAG pumped Ti:sapphire laser system for colliding beam experiments or a flash lamp pumped Ti:sapphire laser for fixed target experiments. It uses a thin, strained GaAs(100) photocathode, and is capable of producing a pulsed beam with a polarization of {ge}80% and a peak current exceeding 10 A. Its operating efficiency has reached 99%. The physics and technology of producing high polarization electron beams from a GaAs photocathode will be reviewed. The prospects of realizing a polarized electron source for future linear colliders will also be discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  6. Early operating experience with the Brookhaven National Laboratory radio frequency quadrupole accelerator

    SciTech Connect

    Brown, H.; Clifford, T.; Giordano, S.; Khiari, F.; McKenzie-Wilson, R.; Puglisi, M.; Warner, P.

    1984-05-01

    The Brookhaven National Laboratory polarized H/sup -/ injection program for the AGS utilizes a Radio Frequency Quadrupole (RFQ) for acceleration between the polarized H/sup -/ source and the Alvarez Linac. The RFQ accelerator is now in operation with low beam currents. The results of low and high power rf testing will be reported together with initial results of operation in the polarized H/sup -/ beam line.

  7. Observation of Ion Acceleration and Heating during Collisionless Magnetic Reconnection in a Laboratory Plasma

    SciTech Connect

    Yoo, Jongsoo; Yamada, Masaaki; Ji, Hantao; Myers, Clayton E.

    2012-12-10

    The ion dynamics in a collisionless magnetic reconnection layer are studied in a laboratory plasma. The measured in-plane plasma potential profile, which is established by electrons accelerated around the electron diffusion region, shows a saddle-shaped structure that is wider and deeper towards the outflow direction. This potential structure ballistically accelerates ions near the separatrices toward the outflow direction. Ions are heated as they travel into the high pressure downstream region.

  8. System tests with electric thruster beam and accelerator directly powered from laboratory solar arrays

    NASA Technical Reports Server (NTRS)

    Stover, J. B.

    1976-01-01

    Laboratory high voltage solar arrays were operated directly connected to power the beam and accelerator loads of an 8-centimeter ion thruster. The beam array comprised conventional 2 by 2 centimeter solar cells; the accelerator array comprised multiple junction edge-illuminated solar cells. Conventional laboratory power supplies powered the thruster's other loads. Tests were made to evaluate thruster performance and to investigate possible electrical interactions between the solar arrays and the thruster. Thruster performance was the same as with conventional laboratory beam and accelerator power supplies. Most of the thruster beam short circuits that occurred during solar array operation were cleared spontaneously without automatic or manual intervention. No spontaneous clearing occurred during conventional power supply operation.

  9. SLAC E144 Plots, Simulation Results, and Data

    DOE Data Explorer

    The 1997 E144 experiments at the Stanford Linear Accelerator Center (SLAC) utilitized extremely high laser intensities and collided huge groups of photons together so violently that positron-electron pairs were briefly created, actual particles of matter and antimatter. Instead of matter exploding into heat and light, light actually become matter. That accomplishment opened a new path into the exploration of the interactions of electrons and photons or quantum electrodynamics (QED). The E144 information at this website includes Feynmann Diagrams, simulation results, and data files. See also aseries of frames showing the E144 laser colliding with a beam electron and producing an electron-positron pair at http://www.slac.stanford.edu/exp/e144/focpic/focpic.html and lists of collaborators' papers, theses, and a page of press articles.

  10. SLAC Next-Generation High Availability Power Supply

    SciTech Connect

    Bellomo, P.; MacNair, D.; ,

    2010-06-11

    SLAC recently commissioned forty high availability (HA) magnet power supplies for Japan's ATF2 project. SLAC is now developing a next-generation N+1 modular power supply with even better availability and versatility. The goal is to have unipolar and bipolar output capability. It has novel topology and components to achieve very low output voltage to drive superconducting magnets. A redundant, embedded, digital controller in each module provides increased bandwidth for use in beam-based alignment, and orbit correction systems. The controllers have independent inputs for connection to two external control nodes. Under fault conditions, they sense failures and isolate the modules. Power supply speed mitigates the effects of fault transients and obviates subsequent magnet standardization. Hot swap capability promises higher availability and other exciting benefits for future, more complex, accelerators, and eventually the International Linear Collider project.

  11. An X-Band Gun Test Area at SLAC

    SciTech Connect

    Limborg-Deprey, C.; Adolphsen, C.; Chu, T.S.; Dunning, M.P.; Jobe, R.K.; Jongewaard, E.N.; Hast, C.; Vlieks, A.E.; Wang, F.; Walz, D.R.; Marsh, R.A.; Anderson, S.G.; Hartemann, F.V.; Houck, T.L.; /LLNL, Livermore

    2012-09-07

    The X-Band Test Area (XTA) is being assembled in the NLCTA tunnel at SLAC to serve as a test facility for new RF guns. The first gun to be tested will be an upgraded version of the 5.6 cell, 200 MV/m peak field X-band gun designed at SLAC in 2003 for the Compton Scattering experiment run in ASTA. This new version includes some features implemented in 2006 on the LCLS gun such as racetrack couplers, increased mode separation and elliptical irises. These upgrades were developed in collaboration with LLNL since the same gun will be used in an injector for a LLNL Gamma-ray Source. Our beamline includes an X-band acceleration section which takes the electron beam up to 100 MeV and an electron beam measurement station. Other X-Band guns such as the UCLA Hybrid gun will be characterized at our facility.

  12. AmeriFlux US-IB1 Fermi National Accelerator Laboratory- Batavia (Agricultural site)

    SciTech Connect

    Matamala, Roser

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-IB1 Fermi National Accelerator Laboratory- Batavia (Agricultural site). Site Description - Two eddy correlation systems are installed at Fermi National Accelerator Laboratory: one on a restored prairie (established October 2004) and one on a corn/soybean rotation agricultural field (established in July 2005). The prairie site had been farmed for more than 100 years, but was converted to prairie in 1989. The agricultural site has likely been farmed for more than 100 years, but the first documented instance of agricultural activity dates back to a picture taken in 1952.

  13. AmeriFlux US-IB2 Fermi National Accelerator Laboratory- Batavia (Prairie site)

    SciTech Connect

    Matamala, Roser

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-IB2 Fermi National Accelerator Laboratory- Batavia (Prairie site). Site Description - Two eddy correlation systems are installed at Fermi National Accelerator Laboratory: one on a restored prairie (established October 2004) and one on a corn/soybean rotation agricultural field (established in July 2005). The prairie site had been farmed for more than 100 years, but was converted to prairie in 1989. April annual to bi-annual prescribed burns have taken place from 1994 - 2007.

  14. ACCELERATION OF LOS ALAMOS NATIONAL LABORATORY TRANSURANIC WASTE DISPOSITION

    SciTech Connect

    O'LEARY, GERALD A.

    2007-01-04

    One of Los Alamos National Laboratory's (LANL's) most significant risks is the site's inventory of transuranic waste retrievably stored above and below-ground in Technical Area (TA) 54 Area G, particularly the dispersible high-activity waste stored above-ground in deteriorating facilities. The high activity waste represents approximately 50% (by activity) of the total 292,000 PE-Ci inventory remaining to be disposed. The transuramic waste inventory includes contact-handled and remote-handled waste packaged in drums, boxes, and oversized containers which are retrievably stored both above and below-ground. Although currently managed as transuranic waste, some of the inventory is low-level waste that can be disposed onsite or at approved offsite facilities. Dispositioning the transuranic waste inventory requires retrieval of the containers from above and below-ground storage, examination and repackaging or remediation as necessary, characterization, certification and loading for shipment to the Waste Isolation Pilot Plant in Carlsbad New Mexico, all in accordance with well-defined requirements and controls. Although operations are established to process and characterize the lower-activity contact-handled transuranic waste containers, LAN L does not currently have the capability to repack high activity contact-handled transuranic waste containers (> 56 PE-Ci) or to process oversized containers with activity levels over 0.52 PE-Ci. Operational issues and compliance requirements have resulted in less than optimal processing capabilities for lower activity contact-handled transuranic waste containers, limiting preparation and reducing dependability of shipments to the Waste Isolation Pilot Plant. Since becoming the Los Alamos National Laboratory contract in June 2006, Los Alamos National Security (LANS) L.L.C. has developed a comprehensive, integrated plan to effectively and efficiently disposition the transuranic waste inventory, working in concert with the Department of

  15. RF Gun Photocathode Research at SLAC

    SciTech Connect

    Jongewaard, E.; Akre, R.; Brachmann, A.; Corbett, J.; Gilevich, S.; Grouev, K.; Hering, P.; P.Krejcik,; Lewandowski, J.; Loos, H.; Montagne, T.; Sheppard, J.C.; Stefan, P.; Vlieks, A.; Weathersby, S.; Zhou, F.; /SLAC

    2012-05-16

    LCLS is presently operating with a third copper photocathode in the original rf gun, with a quantum efficiency (QE) of {approx}1 x 10{sup -4} and projected emittance {gamma}{var_epsilon}{sub x,y} = 0.45 {micro}m at 250 pC bunch charge. The spare LCLS gun is installed in the SLAC Accelerator Structure Test Area (ASTA), fully processed to high rf power. As part of a wider photocathode R and D program, a UV laser system and additional gun diagnostics are being installed at ASTA to measure QE, QE lifetime, and electron beam emittance under a variety of operating conditions. The near-term goals are to test and verify the spare photocathode production/installation sequence, including transfer from the final holding chamber to the rf gun. Mid- and longer-term goals include development of a rigorous understanding of plasma and laser-assisted surface conditioning and investigation of new, high-QE photocathode materials. In parallel, an x-ray photoemission spectroscopy station is nearing completion, to analyze Cu photocathode surface chemistry. In this paper we review the status and anticipated operating parameters of ASTA and the spectroscopy test chamber.

  16. The SLAC Vertical Comparator for the Calibration of Digital Levels

    SciTech Connect

    Woschitz, Helmut; Gassner, Georg; Ruland, Robert; /SLAC

    2006-12-06

    Digital levels replaced spirit levels in most fields of precise height measurements because of the automation of the height readings. Three manufacturers offer digital levels with a single reading resolution of 10 {micro}m, and for all of them systematic effects are known. In Europe several facilities for system calibration of digital levels using vertical comparators were established within the last decade. However, there still was no system calibration facility in North America. In order to guarantee the accuracy required for the alignment of experiments at the Stanford Linear Accelerator Center (SLAC) a calibration facility for the system calibration of digital levels was built. In this paper the setup of the SLAC vertical comparator is described in detail and its standard uncertainty is derived. In order to perform traditional rod calibration of conventional line-scaled rods, a CCD camera was integrated into the SLAC comparator. The CCD camera setup is also briefly described. To demonstrate the capabilities of the comparator, results of system and rod calibration are shown.

  17. Latest Results in SLAC 75-MW PPM Klystrons

    SciTech Connect

    Sprehn, D.; Caryotakis, G.; Haase, A.; Jongewaard, E.; Laurent, L.; Pearson, C.; Phillips, R.; /SLAC

    2006-03-06

    75 MW X-band klystrons utilizing Periodic Permanent Magnet (PPM) focusing have been undergoing design, fabrication and testing at the Stanford Linear Accelerator Center (SLAC) for almost nine years. The klystron development has been geared toward realizing the necessary components for the construction of the Next Linear Collider (NLC). The PPM devices built to date which fit this class of operation consist of a variety of 50 MW and 75 MW devices constructed by SLAC, KEK (Tsukuba, Japan) and industry. All these tubes follow from the successful SLAC design of a 50 MW PPM klystron in 1996. In 2004 the latest two klystrons were constructed and tested with preliminary results reported at EPAC2004. The first of these two devices was tested to the full NLC specifications of 75 MW, 1.6 microseconds pulse length, and 120 Hz. This 14.4 kW average power operation came with a tube efficiency >50%. The most recent testing of these last two devices will be presented here. Design and manufacturing issues of the latest klystron, due to be tested by the Fall of 2005, are also discussed.

  18. Environmental Survey preliminary report, Stanford Linear Accelerator Center, Stanford, California

    SciTech Connect

    Not Available

    1988-07-01

    This report presents the preliminary findings from the first phase of the Survey of the US Department of Energy (DOE) Stanford Linear Accelerator Center (SLAC) at Stanford, California, conducted February 29 through March 4, 1988. The Survey is being conducted by an interdisciplinary team of environmental specialists, led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual team components are being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with the SLAC. The Survey covers all environmental media and all areas of environmental regulation and is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations at the SLAC, and interviews with site personnel. The Survey team is developing a Sampling and Analysis Plan to assist in further assessing certain of the environmental problems identified during its on-site activities. The Sampling and Analysis Plan will be executed by a DOE National Laboratory or a support contractor. When completed, the results will be incorporated into the Environmental Survey Interim Report for the SLAC facility. The Interim Report will reflect the final determinations of the SLAC Survey. 95 refs., 25 figs., 25 tabs.

  19. 2011 Dielectric Laser Acceleration Workshop (DLA2011)

    SciTech Connect

    Bermel, Peter; Byer, Robert L.; Colby, Eric R.; Cowan, Benjamin M.; Dawson, Jay; England, R.Joel; Noble, Robert J.; Qi, Ming-Hao; Yoder, Rodney B.; /Manhattanville Coll., Purchase

    2012-04-17

    The first ICFA Mini-workshop on Dielectric Laser Accelerators was held on September 15-16, 2011 at SLAC National Accelerator Laboratory. We present the results of the Workshop, and discuss the main conclusions of the Accelerator Applications, Photonics, and Laser Technologies working groups. Over 50 participants from 4 countries participated, discussing the state of the art in photonic structures, laser science, and nanofabrication as it pertains to laser-driven particle acceleration in dielectric structures. Applications of this new and promising acceleration concept to discovery science and industrial, medical, and basic energy sciences were explored. The DLA community is presently focused on making demonstrations of high gradient acceleration and a compatible attosecond injector source - two critical steps towards realizing the potential of this technology.

  20. Reliability of Operation at SLAC in the LCLS Era

    SciTech Connect

    Wienands, U.; Allen, W.B.; Colocho, W.; Erickson, R.; Stanek, M.; /SLAC

    2009-06-19

    LCLS hardware availability has been above 90% for the first two commissioning runs of the accelerator. In this paper we compare the reliability data for LCLS (availability, MTBF and MTTR) to those of PEP-II, the e{sup +}e{sup -} collider operating previously at SLAC. It may be seen that the linac availability is not significantly different now than it was before, while the availability of the whole LCLS facility is significantly higher than that of the PEP-II facility as a whole (which was about 87%). Most of the improvement is in the MTTR. Ways to improve availability towards the goal of 95% are discussed.

  1. Commissioning the Echo-Seeding Experiment Echo-7 at SLAC

    SciTech Connect

    Weathersby, S.a E.Colby; Dunning, M.; Gilevich, S.; Hast, C.; Jobe, K.; McCormick, D.; Nelson, J.; Raubenheimer, T.O.; Soong, K.; Stupakov, G.; Szalata, Z.; Walz, D.; Woodley, M.; Xiang, D.; Pernet, P-L.; /Ecole Polytechnique, Lausanne

    2011-06-02

    ECHO-7 is a proof-of-principle echo-enabled harmonic generation (EEHG) FEL experiment in the Next Linear Collider Test Accelerator (NLCTA) at SLAC. The experiment is intended to test the EEHG principle at low electron beam energy, 120 MeV, and determine the sensitivities and limitations to understand the expected performance at the higher energy scales and harmonic numbers required for x-ray FELs. In this paper we present the experimental results from the commissioning run of the completed experimental setup which started in April 2010.

  2. Short wavelength FELs using the SLAC linac

    SciTech Connect

    Winick, H.; Bane, K.; Boyce, R.

    1993-08-01

    Recent technological developments have opened the possibility to construct a device which we call a Linac Coherent Light Source (LCLS); a fourth generation light source, with brightness, coherence, and peak power far exceeding other sources. Operating on the principle of the free electron laser (FEL), the LCLS would extend the range of FEL operation to much aborter wavelength than the 240 mn that has so far been reached. We report the results of studies of the use of the SLAC linac to drive an LCLS at wavelengths from about 3-100 nm initially and possibly even shorter wavelengths in the future. Lasing would be achieved in a single pass of a low emittance, high peak current, high energy electron beam through a long undulator. Most present FELs use an optical cavity to build up the intensity of the light to achieve lasing action in a low gain oscillator configuration. By eliminating the optical cavity, which is difficult to make at short wavelengths, laser action can be extended to shorter wavelengths by Self-Amplified-Spontaneous-Emission (SASE), or by harmonic generation from a longer wavelength seed laser. Short wavelength, single pass lasers have been extensively studied at several laboratories and at recent workshops.

  3. High transformer ratio drive beams for wakefield accelerator studies

    SciTech Connect

    England, R. J.; Ng, C.-K.; Frederico, J.; Hogan, M. J.; Litos, M.; Muggli, P.; Joshi, C.; An, W.; Andonian, G.; Mori, W.; Lu, W.

    2012-12-21

    For wakefield based acceleration schemes, use of an asymmetric (or linearly ramped) drive bunch current profile has been predicted to enhance the transformer ratio and generate large accelerating wakes. We discuss plans and initial results for producing such bunches using the 20 to 23 GeV electron beam at the FACET facility at SLAC National Accelerator Laboratory and sending them through plasmas and dielectric tubes to generate transformer ratios greater than 2 (the limit for symmetric bunches). The scheme proposed utilizes the final FACET chicane compressor and transverse collimation to shape the longitudinal phase space of the beam.

  4. X-BAND KLYSTRON DEVELOPMENT AT SLAC

    SciTech Connect

    Vlieks, Arnold E.; /SLAC

    2009-08-03

    The development of X-band klystrons at SLAC originated with the idea of building an X-band Linear Collider in the late 1980's. Since then much effort has been expended in developing a reliable X-band Power source capable of delivering >50 MW RF power in pulse widths >1.5 {micro}s. I will report on some of the technical issues and design strategies which have led to the current SLAC klystron designs.

  5. The development of seismic guidelines for the Stanford Linear Accelerator Center

    SciTech Connect

    Huggins, R.

    1996-08-01

    This paper describes the development of Seismic Guidelines for the Stanford Linear Accelerator Center (SLAC). Although structures have always been built conservatively, SLAC management decided to review and update their seismic guidelines. SLAC is about mid-way between the epicenters of the 8.3 Richter magnitude 1906 San Francisco and the 7.2 Loma Prieta Earthquakes. The west end of the two mile long electron/positron particle accelerator lies a half mile from the large San Andreas Fault. Suggestions for seismic planning processes were solicited from local computer manufacturing firms, universities, and federal laboratories. A Committee of the various stakeholders in SLAC`s seismic planning retained an internationally known Seismic Planning Consultant and reviewed relevant standards and drafted Guidelines. A panel of seismic experts was convened to help define the hazard, site response spectra, probabilistic analysis of shaking, and near field effects. The Facility`s structures were assigned to seismic classes of importance, and an initial assessment of a sample of a dozen buildings conducted. This assessment resulted in emergency repairs to one structure, and provided a {open_quotes}reality basis{close_quotes} for establishing the final Guidelines and Administrative Procedures, and a program to evaluate remaining buildings, shielding walls, tunnels, and other special structures.

  6. SLAC 5045 klystron technical specification SC-700-866-45-R3 (Engineering Materials)

    SciTech Connect

    Not Available

    1984-05-09

    The purpose of this specification is to define the performance characteristics of improved klystrons for operation at the Stanford Linear Accelerator Center. Each klystron shall be capable of supplying 50 megawatts peak, 45 kilowatts average rf power at 2856 Megahertz. It is expected that over the next few years, existing SLAC klystrons will be replaced by the improved klystrons covered by this specification. It is desirable that the klystrons covered by this specification be usable with magnets designed by SLAC under specification No. SC-700-866-46. Recently SLAC has been able to achieve a klystron efficiency in excess of 45% and design information of tubes which have exhibited this efficiency is available. It must be emphasized that one of the most important features of tubes designed to operate to these specifications must be long life. The overall economy of the SLAC linear accelerator program is strongly influenced by klystron life and it is expected that the design of this tube can lead to a minimum operating life equal to that experienced with the older klystrons. In order to increase the probability of long life, SLAC expects to operate the tubes conservatively at 315 kV beam voltage which is approximately 5 kV below the maximum allowed by the specifications. However, it is expected that from time to time, as required by physics experiments, the tubes will be operated at the maximum power allowed.

  7. The X-band klystron program at SLAC

    SciTech Connect

    Caryotakis, G.

    1996-04-01

    The X-band rf source development at SLAC can be considered a qualified success. A total of twelve klystrons were built. Six of them are still in use. The latest tube, XL4, produced 75 MW at an efficiency of 47.5 percent. However, victory cannot be declared as yet, since an NLC prototype has not been fully designed and the decision between permanent magnet focusing and a super-conducting solenoid has not been formally made. Daryl Sprehn`s paper will present the status of the PPM klystron development. The authors believe that a PPM X-band source will work, at 50 as well as at 75 megawatts. But they are prepared to adapt the XL4 design to a super-conducting solenoid, should the PPM klystron develop unexpected problems. The SLAC program is now in its seventh year. It may well be the longest and most expensive microwave tube development on record, in a government laboratory or in industry. Direct and related costs for the total effort are probably of the order of $10 million. In these circumstances it is perhaps not surprising that it has been possible to produce a klystron with the performance of XL4. At the same time, it must be said that the necessary leap in technology from the SLAC 60-megawatt S-band production klystrons to a klystron of comparable performance at four times the frequency could not be realized without some very careful experimentation and, most importantly, without the infrastructure for tube fabrication and testing available at SLAC. The design of an 11.4 GHz 50--100 MW klystron, with microsecond pulses and a pulse repetition frequency of 180 Hz presents a number of technical challenges which are listed here.

  8. Collisionless shocks and particle acceleration in laser-driven laboratory plasmas

    NASA Astrophysics Data System (ADS)

    Fiuza, Frederico

    2012-10-01

    Collisionless shocks are pervasive in space and astrophysical plasmas, from the Earth's bow shock to Gamma Ray Bursters; however, the microphysics underlying shock formation and particle acceleration in these distant sites is not yet fully understood. Mimicking these extreme conditions in laboratory is a grand challenge that would allow for a better understanding of the physical processes involved. Using ab initio multi-dimensional particle-in-cell simulations, shock formation and particle acceleration are investigated for realistic laboratory conditions associated with the interaction of intense lasers with high-energy-density plasmas. Weibel-instability-mediated shocks are shown to be driven by the interaction of an ultraintense laser with overcritical plasmas. In this piston regime, the laser generates a relativistic flow that is Weibel unstable. The strong Weibel magnetic fields deflect the incoming flow, compressing it, and forming a shock. The resulting shock structure is consistent with previous simulations of relativistic astrophysical shocks, demonstrating for the first time the possibility of recreating these structures in laboratory. As the laser intensity is decreased and near-critical density plasmas are used, electron heating dominates over radiation pressure and electrostatic shocks can be formed. The electric field associated with the shock front can reflect ions from the background accelerating them to high energies. It is shown that high quality 200 MeV proton beams, required for tumor therapy, can be generated by using an exponentially decaying plasma profile to control competing accelerating fields. These results pave the way for the experimental exploration of space and astrophysical relevant shocks and particle acceleration with current laser systems.

  9. Big Machines and Big Science: 80 Years of Accelerators at Stanford

    SciTech Connect

    Loew, Gregory

    2008-12-16

    Longtime SLAC physicist Greg Loew will present a trip through SLAC's origins, highlighting its scientific achievements, and provide a glimpse of the lab's future in 'Big Machines and Big Science: 80 Years of Accelerators at Stanford.'

  10. ESTB: A New Beam Test Facility at SLAC

    SciTech Connect

    Pivi, M.; Fieguth, T.; Hast, C.; Iverson, R.; Jaros, J.; Jobe, K.; Keller, L.; Walz, D.; Weathersby, S.; Woods, M.; /SLAC

    2011-04-05

    End Station A Test Beam (ESTB) is a beam line at SLAC using a small fraction of the bunches of the 13.6 GeV electron beam from the Linac Coherent Light Source (LCLS), restoring test beam capabilities in the large End Station A (ESA) experimental hall. ESTB will provide one of a kind test beam essential for developing accelerator instrumentation and accelerator R&D, performing particle and particle astrophysics detector research, linear collider machine and detector interface (MDI) R&D studies, development of radiation-hard detectors, and material damage studies with several distinctive features. In the past, 18 institutions participated in the ESA program at SLAC. In stage I, 4 new kicker magnets will be added to divert 5 Hz of the LCLS beam to the A-line. A new beam dump will be installed and a new Personnel Protection System (PPS) is being built in ESA. In stage II, a secondary hadron target will be installed, able to produce pions up to about 12 GeV/c at 1 particle/pulse.

  11. Prospects of High Energy Laboratory Astrophysics

    SciTech Connect

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

    2006-09-21

    Ultra high energy cosmic rays (UHECR) have been observed but their sources and production mechanisms are yet to be understood. We envision a laboratory astrophysics program that will contribute to the understanding of cosmic accelerators with efforts to: (1) test and calibrate UHECR observational techniques, and (2) elucidate the underlying physics of cosmic acceleration through laboratory experiments and computer simulations. Innovative experiments belonging to the first category have already been done at the SLAC FFTB. Results on air fluorescence yields from the FLASH experiment are reviewed. Proposed future accelerator facilities can provided unprecedented high-energy-densities in a regime relevant to cosmic acceleration studies and accessible in a terrestrial environment for the first time. We review recent simulation studies of nonlinear plasma dynamics that could give rise to cosmic acceleration, and discuss prospects for experimental investigation of the underlying mechanisms.

  12. Application of the EXPERT consultation system to accelerated laboratory testing and interpretation.

    PubMed

    Van Lente, F; Castellani, W; Chou, D; Matzen, R N; Galen, R S

    1986-09-01

    The EXPERT consultation system-building tool, a knowledge-based artificial intelligence program developed at Rutgers University, has been applied to the development of a laboratory consultation system facilitating sequential laboratory testing and interpretation. Depending on the results of a basic panel of laboratory tests, the system requests that specific secondary tests be performed. Input of these secondary findings can result in requests for tertiary testing, to complete the database necessary for interpretation. Interpretation of all results is based upon final inferences from the collected findings through a series of rules, a hierarchical network that yields an efficient production system not easily obtained through conventional programming. The rules included in this model are based upon initial results for total protein, calcium, glucose, total bilirubin, alkaline phosphatase, lactate dehydrogenase, aspartate aminotransferase, thyroxin, hemoglobin, mean corpuscular volume, and the concentrations of four drugs. Pertinent clinical history items included are jaundice, diabetes, thyroid disease, medications, and ethanol. Implementing this system in a laboratory-based accelerated testing program involving outpatients maximized the effective use of laboratory resources, eliminated useless testing, and provided the patient with low-cost laboratory information. PMID:3527478

  13. Studies of Multipactor in Dielectric-Loaded Accelerator Structures: Comparison of Simulation Results with Experimental Data

    SciTech Connect

    Sinitsyn, Oleksandr; Nusinovich, Gregory; Antonsen, Thomas Jr.

    2010-11-04

    In this paper new results of numerical studies of multipactor in dielectric-loaded accelerator structures are presented. The results are compared with experimental data obtained during recent studies of such structures performed by Argonne National Laboratory, the Naval Research Laboratory, SLAC National Accelerator Laboratory and Euclid TechLabs, LLC. Good agreement between the theory and experiment was observed for the structures with larger inner diameter, however the structures with smaller inner diameter demonstrated a discrepancy between the two. Possible reasons for such discrepancy are discussed.

  14. The SLAC linac as used in the SLC collider

    SciTech Connect

    Seeman, J.T.; Abrams, G.; Adolphsen, C.; Atwood, W.; Bane, K.L.F.; Iverson, R.; Jacobsen, R.; Himel, T.M.; Jobe, R.K.; Lavine, T.L.

    1989-06-01

    The linac of the SLAC Linear Collider (SLC) must accelerate three high intensity bunches on each linac pulse from 1.2 GeV to 50 GeV with minimal increase of the small transverse emittance. The procedures and adjustments used to obtain this goal are outlined. Some of the accelerator parameters and components which interact are the beam energy, transverse position, component alignment, RF manipulation, feedback systems, quadrupole lattice, BNS damping, energy spectra, phase space matching, collimation, instrumentation and modelling. The method to bring these interdependent parameters collectively into specification has evolved over several years. This review is ordered in the sequence which is used to turn on the linac from a cold start and produce acceptable beams for the final focus and collisions. Approximate time estimates for the various activities are given. 21 refs.

  15. High voltage pulse cable and connector experience in the kicker systems at SLAC

    SciTech Connect

    Harris, K.; Artusy, M.; Donaldson, A.; Mattison, T.

    1991-05-01

    The SLAC 2-mile linear accelerator uses a wide variety of pulse kicker systems that require high voltage cable and connectors to deliver pulses from the drivers to the magnet loads. Many of the drivers in the SLAC kicker systems use cable lengths up to 80 feet and are required to deliver pulses up to 40 kV, with rise and fall time on the order of 20 ns. Significant pulse degradation from the cable and connector assembly cannot be tolerated. Other drivers are required to deliver up to 80 kV, 20 {mu}s pulses over cables 20 feet long. Several combinations of an applicable high voltage cable and matching connector have been used at SLAC to determine the optimum assembly that meets the necessary specifications and is reliable. 14 refs., 3 figs., 1 tab.

  16. SLAC modulator operation and reliability in the SLC Era

    SciTech Connect

    Donaldson, A.R.; Ashton, J.R.

    1992-06-01

    A discussion of the operation and reliability of the 244 modulators in the SLAC linac with an emphasis on the past three years of operation. The linac modulators were designed and built in the 60's, upgraded for the SLAC Linear Collider (SLC) in the mid 80s, and despite their age are still reliable accelerator components. The 60s modulator operated at 65 MW peak and 83 kW average power. The upgrade resulted in 150 MW peak output at an average power of 87 kW, a modest increase since the repetition rate was dropped from 360 to 120 Hz. In the present accelerator configuration, the Linac operates as a source of electrons and positrons to a single pass coillider. The classic collider is a storage ring filled with oppositely charged, counter-rotating particles which are allowed to collide until an accelerator fault occurs and the stored beams are aborted. A reasonable storage ring can store and collide particles for as long as eight hours with a 10 or 20 minute filling time. A single pass collider, + on the other hand, can only produce e{sup {minus}} and e{sup +} collisions at whatever rate the source operates. To be effective the SLC must operate at 120 Hz with a very high degree of reliability and on a continuous basis. Fortunately, the linac has a modest excess of modulator/klystron systems which allows some measure of redundancy and hence some freedom from the constraint that all 244 modulator/klystrons operate simultaneously. Nonetheless, high importance is placed on modulator MTBF and MTRR or, in the parlance of reliability experts and accelerator physicists, availability. This is especially true of the modulators associated with the fundamental requirements of a collider such as injection, compression and positron production.

  17. SLAC modulator operation and reliability in the SLC Era

    SciTech Connect

    Donaldson, A.R.; Ashton, J.R.

    1992-06-01

    A discussion of the operation and reliability of the 244 modulators in the SLAC linac with an emphasis on the past three years of operation. The linac modulators were designed and built in the 60`s, upgraded for the SLAC Linear Collider (SLC) in the mid 80s, and despite their age are still reliable accelerator components. The 60s modulator operated at 65 MW peak and 83 kW average power. The upgrade resulted in 150 MW peak output at an average power of 87 kW, a modest increase since the repetition rate was dropped from 360 to 120 Hz. In the present accelerator configuration, the Linac operates as a source of electrons and positrons to a single pass coillider. The classic collider is a storage ring filled with oppositely charged, counter-rotating particles which are allowed to collide until an accelerator fault occurs and the stored beams are aborted. A reasonable storage ring can store and collide particles for as long as eight hours with a 10 or 20 minute filling time. A single pass collider, + on the other hand, can only produce e{sup {minus}} and e{sup +} collisions at whatever rate the source operates. To be effective the SLC must operate at 120 Hz with a very high degree of reliability and on a continuous basis. Fortunately, the linac has a modest excess of modulator/klystron systems which allows some measure of redundancy and hence some freedom from the constraint that all 244 modulator/klystrons operate simultaneously. Nonetheless, high importance is placed on modulator MTBF and MTRR or, in the parlance of reliability experts and accelerator physicists, availability. This is especially true of the modulators associated with the fundamental requirements of a collider such as injection, compression and positron production.

  18. An improved 8 GeV beam transport system for the Fermi National Accelerator Laboratory

    SciTech Connect

    Syphers, M.J.

    1987-06-01

    A new 8 GeV beam transport system between the Booster and Main Ring synchrotrons at the Fermi National Accelerator Laboratory is presented. The system was developed in an effort to improve the transverse phase space area occupied by the proton beam upon injection into the Main Ring accelerator. Problems with the original system are described and general methods of beamline design are formulated. Errors in the transverse properties of a beamline at the injection point of the second synchrotron and their effects on the region in transverse phase space occupied by a beam of particles are discussed. Results from the commissioning phase of the project are presented as well as measurements of the degree of phase space dilution generated by the transfer of 8 GeV protons from the Booster synchrotron to the Main Ring synchrotron.

  19. Installation of a cw radiofrequency quadrupole accelerator at Los Alamos National Laboratory

    SciTech Connect

    Schneider, J.D.; Bolme, J.; Brown, V.

    1994-09-01

    Chalk River Laboratories (CRL) has had a long history of cw proton beam development for production of intense neutron sources and fissile fuel breeders. In 1986 CRL and Los Alamos National Laboratory (LANL) entered into a collaborative effort to establish a base technologies program for the development of a cw radiofrequency quadrupole (RFQ). The initial cw RFQ design had 50-keV proton injection energy with 600-keV output energy. The 75-mA design current at 600-keV beam energy was obtained in 1990. Subsequently, the RFQ output energy was increased to 1250 keV by replacing the RFQ vanes, still maintaining the 75-m A design current. A new 250-kW cw klystrode rf power source at 267-MHz was installed at CRL. By April of 1993, 55-mA proton beams had been accelerated to 1250 keV. Concurrent developments were taking place on proton source development and on 50-keV low-energy beam transport (LEBT) systems. Development of a dc, high-proton fraction ({ge} 70%) microwave ion source led to utilization of a single-solenoid RFQ direct injection scheme. It was decided to continue this cw RFQ demonstration project at Los Alamos when the CRL project was terminated in April 1993. The LANL goals are to find the current limit of the 1250-keV RFQ, better understand the beam transport properties through the single-solenoid focusing LEBT, continue the application of the cw klystrode tube technology to accelerators, and develop a two-solenoid LEBT which could be the front end of an Accelerator-Driven Transmutation Technologies (ADTT) linear accelerator.

  20. S-Band Loads for SLAC Linac

    SciTech Connect

    Krasnykh, A.; Decker, F.-J.; LeClair, R.; /INTA Technologies, Santa Clara

    2012-08-28

    The S-Band loads on the current SLAC linac RF system were designed, in some cases, 40+ years ago to terminate 2-3 MW peak power into a thin layer of coated Kanthal material as the high power absorber [1]. The technology of the load design was based on a flame-sprayed Kanthal wire method onto a base material. During SLAC linac upgrades, the 24 MW peak klystrons were replaced by 5045 klystrons with 65+ MW peak output power. Additionally, SLED cavities were introduced and as a result, the peak power in the current RF setup has increased up to 240 MW peak. The problem of reliable RF peak power termination and RF load lifetime required a careful study and adequate solution. Results of our studies and three designs of S-Band RF load for the present SLAC RF linac system is discussed. These designs are based on the use of low conductivity materials.

  1. Hazards analysis for the E.O. Lawrence Berkeley National Laboratory x-ray absorption experiments to be performed at Stanford Synchrotron Radiation Laboratory

    SciTech Connect

    Edelstein, N.M.; Shuh, D.K.; Bucher, J.B.

    1995-04-01

    The objective of this experiment is to determine the oxidation state(s) of neptunium (Np) in mouse skeleton and in soft tissue by X-ray Absorption Near Edge Structure (XANES). If Np is present in sufficient concentration, X-ray Absorption Fine Structure (XAFS) data will be obtained in order to further identify the Np species present. These data will be crucial in understanding the metabolic pathway of Np in mammals which will help in the design of reagents which can eliminate Np from mammals in the event of accidental exposure. It is proposed to run these experiments at the Standard Synchrotron Radiation Laboratory (SSRL). This laboratory is a DOE national user facility located at the Stanford Linear Accelerator Center (SLAC). The {sup 237}Np nucleus decays by the emission of an alpha particle and this particle emission is the principal hazard in handling Np samples. This hazard is mitigated by physical containment of the sample which stops the alpha particles within the containment. The total amount of Np material that will be shipped to and be at SSRL at any one time will be less than 1 gram. This limit on the amount of Np will ensure that SLAC remains a low hazard, non-nuclear facility. The Np samples will be solids or Np ions in aqueous solution. The Np samples will be shipped to SSRL/SLAC OHP. SLAC OHP will inventory the samples and swipe the containers holding the triply contained samples, and then bring them to the SSRL Actinide trailer located outside building 131. The QA counting records from the samples, as measured at LBNL, will be provided to SSRL and SLAC OHP prior to the arrival of the samples at SLAC OHP. In addition, strict monitoring of the storage and experimental areas will be performed in accordance with SLAC/OHP radiation protection procedures to ensure against the release of contamination.

  2. Plasma Wakefield Acceleration of Positrons

    NASA Astrophysics Data System (ADS)

    Gessner, Spencer

    2016-03-01

    Recent particle beam and laser-driven plasma wakefield experiments have produced high-quality electron beams accelerated by a GeV or more in less than a meter. Efforts are underway to put these beams to work as sources for free-electron lasers. By contrast, little work has been done to demonstrate the tractability of plasma wakefield acceleration (PWFA) of positrons beams. The reasons for this are threefold: 1) positron beams are only useful for high-energy physics experiments, whereas electron beams are also useful as light sources, 2) there is a dearth of positron sources for PWFA experiments, and 3) the dynamics of accelerating positron beams in plasma is fundamentally different than that of electron beams. This talk will focus on the physics of accelerating positrons in plasma and contrast the dynamics of electron and positron beam-driven nonlinear plasma wakes. We describe recent experiments at the FACET test facility at SLAC National Accelerator Laboratory that for the first time demonstrate high-gradient acceleration of a positron beams in plasma. We also discuss an alternative acceleration technique called hollow channel acceleration that aims to symmetrize the dynamics of electron and positron beam-driven wakes.

  3. Development of a 20-MeV Dielectric-Loaded Accelerator Test Facility

    SciTech Connect

    Gold, S.H.; Kinkead, A.K.; Gai, W.; Power, J.G.; Konecny, R.; Jing, C.G.; Tantawi, S.G.; Nantista, C.D.; Hu, Y.; Chen, H.; Tang, C.; Lin, Y.; Bruce, R.W.; Bruce, R.L.; Fliflet, A.W.; Lewis, D.; /Naval Research Lab, Wash., D.C. /LET Corp., Washington /Argonne /SLAC /Tsinghua U., Beijing

    2005-06-22

    This paper describes a joint project by the Naval Research Laboratory (NRL) and Argonne National Laboratory (ANL), in collaboration with the Stanford Linear Accelerator Center (SLAC), to develop a dielectric-loaded accelerator (DLA) test facility powered by a high-power 11.424-GHz magnicon amplifier. The magnicon can presently produce 25 MW of output power in a 250-ns pulse at 10 Hz, and efforts are in progress to increase this to 50 MW. The facility will include a 5 MeV electron inector being developed by the Accelerator Laboratory of Tsinghua University in Beijing, China. The DLA test structures are being developed by ANL, and some have undergone testing at NRL at gradients up to {approx} 8 MV/m. SLAC is developing a means to combine the two magnicon output arms, and to drive an injector and accelerator with separate control of the power ratio and relative phase. RWBruce Associates, Inc., working with NRl, is developing a means to join short ceramic sections into a continuous accelerator tube by ceramic brazing using an intense millimeter-wave beam. The installation and testing of the first dielectric-loaded test accelerator, including injector, DLA structure, and spectrometer, should take place within the next year. The facility will be used for testing DLA structures using a variety of materials and configurations, and also for testing other X-band accelerator concepts. The initial goal is to produce a compact 20 MeV dielectric-loaded test accelerator.

  4. Recording PEP2 Ring Beam Losses at SLAC

    SciTech Connect

    Zelazny, M.; Gromme, T.; Himel, T.; Hendrickson, L.; Krauter, K.; /SLAC

    2005-09-30

    The PEP2 (e+)(e-) storage rings contain many complex interrelated systems. When the beam aborts, examining a record of the orbit from the time just before the abort can help identify the root cause. At the Stanford Linear Accelerator Center (SLAC) a system has been developed to continuously record beam orbits from Beam Position Monitors (BPMS) into a circular buffer. When the beam is aborted the buffers are frozen and their contents are stored for later analysis. BPM orbits are saved on a turn by turn basis for 2800 turns in both the high energy ring (HER) and the low energy ring (LER). Each BPM Processor (BPMP) can either monitor the HER or the LER, but not both as the readout of the two rings is multiplexed into a single readout channel. Tools exist as part of the SLAC Control Program (SCP) to collect, display, and save the data. A physicist or operator can choose a few BPMS in which to view all 2800 turns to identify the turn in which the beam went awry; then ask for that specific orbit from all of the BPMS in the storage ring to determine the root cause of the abort.

  5. The UNAM sets up the first Laboratory on Accelerator Mass Spectrometry (LEMA) in Mexico

    NASA Astrophysics Data System (ADS)

    Solís, C.; Chávez, E.; Ortíz, M. E.; Andrade, E.

    2013-05-01

    A new Accelerator Mass Spectrometry system is being installed at the Institute of Physics of the National Autonomous University of Mexico (IFUNAM) with support of CONACYT and UNAM. The AMS system is based on a tandetron accelerator of 1MV purchased from the High Voltage Engineering Europe B.V., Amersfoort, the Netherlands. Mass spectrometry experiments will be conducted at the AMS laboratory (LEMA), for analysis of 14 C and other isotopes as the 10Be, 26Al, 129I and Pu. This is a highly sensitive technique that allows to measure concentrations up to one part in 1015 from different nuclei. LEMA is the first laboratory in Mexico of its kind and the second in Latin America, after Brazil. The first research line of LEMA is to apply AMS for dating with 14C. Once the dating methodologies will be implemented, we will incorporate the analysis of other radioisotopes in research projects in different areas such as the Geophysical and Environmental sciences. In this presentation, the AMS system as well as details on the sample preparation will be described. Also, results from installation and acceptance tests will be presented.

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  7. Recent Ground Motion Studies at SLAC

    SciTech Connect

    Seryi, Andrei

    2000-06-28

    Studies of slow ground motion have recently been performed at SLAC using the linac laser alignment system over a period of one month. Two significant effects responsible for the observed motion have been identified, namely tidal forces and variation of external atmospheric pressure. The latter is of particular interest as it may result in misalignments with rather short wavelength.

  8. SLAC All Access: X-ray Microscope

    SciTech Connect

    Nelson, Johanna; Liu, Yijin

    2012-08-14

    SLAC physicists Johanna Nelson and Yijin Liu give a brief overview of the X-ray microscope at the Stanford Synchrotron Radiation Lightsource (SSRL) that is helping improve rechargeable-battery technology by letting researchers peek into the inner workings of batteries as they operate.

  9. SLAC All Access: X-ray Microscope

    ScienceCinema

    Nelson, Johanna; Liu, Yijin

    2014-06-13

    SLAC physicists Johanna Nelson and Yijin Liu give a brief overview of the X-ray microscope at the Stanford Synchrotron Radiation Lightsource (SSRL) that is helping improve rechargeable-battery technology by letting researchers peek into the inner workings of batteries as they operate.

  10. Archimedes: Accelerator Reveals Ancient Text

    SciTech Connect

    Bergmann, Uwe

    2004-02-24

    Archimedes (287-212 BC), who is famous for shouting 'Eureka' (I found it) is considered one of the most brilliant thinkers of all times. The 10th-century parchment document known as the 'Archimedes Palimpsest' is the unique source for two of the great Greek's treatises. Some of the writings, hidden under gold forgeries, have recently been revealed at the Stanford Synchrotron Radiation Laboratory at SLAC. An intense x-ray beam produced in a particle accelerator causes the iron in original ink, which has been partly erased and covered, to send out a fluorescence glow. A detector records the signal and a digital image showing the ancient writings is produced. Please join us in this fascinating journey of a 1,000-year-old parchment from its origin in the Mediterranean city of Constantinople to a particle accelerator in Menlo Park.

  11. PEP-II Large Power Supplies Rebuild Program at SLAC

    SciTech Connect

    Bellomo, P.; Lipari, J.J.; de Lira, A.C.; Rafael, F.S.; /SLAC

    2005-05-17

    Seven large power supplies (LGPS) with output ratings from 72kW to 270kW power PEP-II quad magnets in the electron-positron collider region. These supplies have posed serious maintenance and reliability problems since they were installed in 1997, resulting in loss of accelerator availability. A redesign/rebuild program was undertaken by the SLAC Power Conversion Department. During the 2004 summer shutdown all the control circuits in these supplies were redesigned and replaced. A new PWM control board, programmable logic controller, and touch panel have been installed to improve LGPS reliability, and to make troubleshooting easier. In this paper we present the details of this rebuilding program and results.

  12. Electron Bunch Length Measurement for LCLS at SLAC

    SciTech Connect

    Zelazny, M.; Allison, S.; Chevtsov, Sergei; Emma, P.; Kotturi, K.d.; Loos, H.; Peng, S.; Rogind, D.; Straumann, T.; /SLAC

    2007-10-04

    At Stanford Linear Accelerator Center (SLAC) a Bunch Length Measurement system has been developed to measure the length of the electron bunch for its new Linac Coherent Light Source (LCLS). This destructive measurement uses a transverse-mounted RF deflector (TCAV) to vertically streak the electron beam and an image taken with an insertable screen and a camera. The device control software was implemented with the Experimental Physics and Industrial Control System (EPICS) toolkit. The analysis software was implemented in Matlab{trademark} using the EPICS/Channel Access Interface for Scilab{trademark} and Matlab{trademark} (labCA). This architecture allowed engineers and physicists to develop and integrate their control and analysis without duplication of effort.

  13. The development of the Next Linear Collider at SLAC

    SciTech Connect

    Ruth, R.D.

    1992-02-01

    At SLAC, we are pursuing the design of a Next Linear Collider (NLC) which would begin with a center-of-mass energy of 0.5 TeV and be upgradable to at least 1.0 TeV, and possibly 1.5 TeV. The luminosity is designed to be 10{sup 33} cm{sup {minus}2}s{sup {minus}1} at the lower energy and 10{sup 34} cm{sup {minus}2}s{sup {minus}1} at the top energy. In this paper, we discuss the accelerator physics issues which are important in our approach, and also the present state of the technology development. We also review the impact that the SLC has had in the evolution of our basic approach.

  14. The ILC Marx Modulator Development Program at SLAC

    SciTech Connect

    Leyh, G.E.; /SLAC

    2005-06-07

    The International Linear Collider [ILC] baseline design requires 576 L-band klystron stations, each supplying 10MW peak RF power to the accelerating structures. Each klystron requires a modulator capable of delivering 120kV, 140A 1.6ms pulses, at 5Hz. Solid-state Marx modulator topologies are rapidly becoming feasible with the advent of PC-board-level 4500V IGBTs, fast single junction HV diodes, high density capacitors, and sophisticated modeling software. Making full use of recent technology advances, the ILC Marx Modulator program at SLAC plans to pursue a 120kV solid-state Marx design, which appears to offer significantly higher efficiency, availability, and cost savings than existing modulator options.

  15. Laboratory Measurements of Linear Electron Acceleration by Inertial Alfvén Waves

    NASA Astrophysics Data System (ADS)

    Schroeder, J. W. R.

    2015-11-01

    Alfvén waves occur in conjunction with a significant fraction of auroral electron acceleration. Inertial mode Alfvén waves (vA >vte) in the auroral magnetosphere (2 - 4RE) with perpendicular scales on the order of the electron skin depth (c /ωpe) have a parallel electric field that, according to theory, is capable of nonlinearly accelerating suprathermal electrons to auroral energies. Unfortunately, due to space-time ambiguities of rocket and satellite measurements, it has not yet been possible to fully verify how Alfvén waves contribute to the production of accelerated electrons. To overcome the limitations of in situ spacecraft data, laboratory experiments have been carried out using the Large Plasma Device (LaPD), an NSF/DOE user facility at UCLA. An Electron Cyclotron Absorption (ECA) diagnostic has been developed to record the suprathermal parallel electron distribution function with 0.1% precision. The diagnostic records the electron distribution while inertial Alfvén waves simultaneously propagate through the plasma. Recent measurements have isolated oscillations of suprathermal electrons at the Alfvén wave frequency. Despite complications from boundary effects and the finite size of the experiment, a linear kinetic model has been produced that describes the experimental results. To our knowledge this is the first quantitative agreement between the measured and modeled linear response of suprathermal electrons to an inertial Alfvén wave. This verification of the linear physics is a necessary step before the nonlinear acceleration process can be isolated in future experiments. Presently, nonlinear effects cannot be detected because of limited Alfvén wave amplitudes. Ongoing work is focused on designing a higher-power antenna capable of efficiently launching larger-amplitude Alfvén waves with tunable perpendicular wavenumber and developing a theoretical understanding of the nonlinear acceleration process in LaPD plasma conditions. This material is

  16. On the effect of accelerated winds on the wave growth through detailed laboratory measurements.

    NASA Astrophysics Data System (ADS)

    Ocampo-Torres, Francisco J.; Branger, Hubert; Osuna, Pedro; Hernández, Aldo

    2013-04-01

    The possible influence of accelerated winds on air-water momentum fluxes is being studied through detailed laboratory measurements in a large wind-wave flume. Wind stress over the water surface, waves and surface drift are measured in the 40m long wind-wave tank at IRPHE, Marseille. While momentum fluxes are estimated directly through the eddy correlation method in a station about the middle of the tank, they provide information corresponding to rather short non-dimensional fetch not previously reported. Wave evolution along the tank is determined through a series of wave gauges, and the wind-induced surface drift is obtained at one of the first measuring stations at the beginning of the tank. At each experimental run very low wind was on (about 1m/s) for a certain period and suddenly it was constantly accelerated to reach about 13 m/s (as well as 8 and 5 m/s during different runs) in about 15 sec to as long as 600 sec. The wind was kept constant at that high speed for 2 to 10 min, and then suddenly and constantly decelerate to 0. Data from the constant high winds provided us with reference equilibrium conditions for at least 3 different wind speed. We, nevertheless, focus in the recordings while wind was being constantly accelerated expecting some contribution to the understanding of gustiness, the implied wind wave growth and the onset of surface drift. Wind-wave growth is observed to lag behind the wind stress signal, and furthermore, a two regime wind stress is noticed, apparently well correlated with a) the incipient growth and appearance of the first waves and b) the arrival of waves from the up-wind section of the tank. Results of non-dimensional wave energy as a function of non-dimensional fetch represent an extension of at least 2 decades shorter non-dimensional fetch to the wave growth curves typically found in the literature. The linear tendency of wave growth compares very well only when wind is reaching its maximum, while during the accelerated wind

  17. Proposed low-level radioactive waste handling building at Fermi National Accelerator Laboratory, Batavia, Illinois

    SciTech Connect

    1995-06-01

    The US Department of Energy (DOE) has prepared an Environmental Assessment (EA), evaluating the impacts associated with the proposed Low-Level Radioactive Waste Building at the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois. As a result of the high energy physics program at Fermilab, small quantities of low-level radioactive wastes are generated. These wastes are collected, sorted and packaged for shipment to an off-site disposal facility in Hanford, Washington. The proposed project includes the construction of a new building to house, all low-level radioactive waste handling operations. The building would provide workspace for five full-time workers. The proposed project would improve the efficiency and safety of the low-level radioactive waste handling at Fermilab by upgrading equipment and consolidating operations into one facility.

  18. Proposed Casey`s Pond Improvement Project, Fermi National Accelerator Laboratory

    SciTech Connect

    1995-05-01

    The U.S. Department of Energy (DOE) has prepared an Environmental Assessment (EA), evaluating the impacts associated with the proposed Casey`s Pond Improvement Project at the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois. The improvement project would maximize the efficiency of the Fermilab Industrial Cooling Water (ICW) distribution system, which removes (via evaporation) the thermal load from experimental and other support equipment supporting the high energy physics program at Fermilab. The project would eliminate the risk of overheating during fixed target experiments, ensure that the Illinois Water Quality Standards are consistently achieved and provide needed additional water storage for fire protection. Based on the analysis in the EA, the DOE has determined that the proposed action does not constitute a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an Environmental Impact Statement is not required.

  19. Availability Performance and Considerations for LCLS X-Ray FEL at SLAC

    SciTech Connect

    Allen, W.B.; Brachmann, A.; Colocho, W.; Stanek, M.; Warren, J.; /SLAC

    2011-08-16

    The Linac Coherent Light Source (LCLS) is an X-ray Free Electron Laser (FEL) facility located at the SLAC National Accelerator Laboratory. LCLS has been in operation since spring 2009, and it has completed its 3rd user run. LCLS is the first in its class of X-ray FEL user facilities, and presents different availability challenges compared to storage ring light sources. This paper presents recent availability performance of the FEL as well as factors to consider when defining the operational availability figure of merit for user runs. During LCLS [1] user runs, an availability of 95% has been set as a goal. In run III, LCLS photon and electron beam systems achieved availabilities of 94.8% and 96.7%, respectively. The total availability goal can be distributed among subsystems to track performance and identify areas that need attention in order to maintain and improve hardware reliability and operational availability. Careful beam time accounting is needed to understand the distribution of down time. The LCLS complex includes multiple experimental hutches for X-ray science, and each user program has different requirements of a set of parameters that the FEL can be configured to deliver. Since each user may have different criteria for what is considered 'acceptable beam', the quality of the beam must be considered to determine the X-ray beam availability.

  20. Laboratory studies of magnetized collisionless flows and shocks using accelerated plasmoids

    NASA Astrophysics Data System (ADS)

    Weber, T. E.; Smith, R. J.; Hsu, S. C.

    2015-11-01

    Magnetized collisionless shocks are thought to play a dominant role in the overall partition of energy throughout the universe, but have historically proven difficult to create in the laboratory. The Magnetized Shock Experiment (MSX) at LANL creates conditions similar to those found in both space and astrophysical shocks by accelerating hot (100s of eV during translation) dense (1022 - 1023 m-3) Field Reversed Configuration (FRC) plasmoids to high velocities (100s of km/s); resulting in β ~ 1, collisionless plasma flows with sonic and Alfvén Mach numbers of ~10. The FRC subsequently impacts a static target such as a strong parallel or anti-parallel (reconnection-wise) magnetic mirror, a solid obstacle, or neutral gas cloud to create shocks with characteristic length and time scales that are both large enough to observe yet small enough to fit within the experiment. This enables study of the complex interplay of kinetic and fluid processes that mediate cosmic shocks and can generate non-thermal distributions, produce density and magnetic field enhancements much greater than predicted by fluid theory, and accelerate particles. An overview of the experimental capabilities of MSX will be presented, including diagnostics, selected recent results, and future directions. Supported by the DOE Office of Fusion Energy Sciences under contract DE-AC52-06NA25369.

  1. A strategy for residual acceleration data reduction and dissemination. [from orbiting space laboratories

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.; Alexander, J. I. D.

    1991-01-01

    A data reduction plan is being developed to efficiently process residual acceleration data from orbiting space laboratories. Implementation of the reduction plan will result in a useful, manageable accelerometer data base which can be readily employed by principal investigators during post-flight analysis of experimental results. The data reduction plan will also assist in the characterization of the acceleration environment of orbiters, which is important for the planning of future experimental missions. Prototype versions of the reduction plan are being tested using accelerometer data recorded during the Spacelab 3 (SL3) mission. Transient disturbances caused by shuttle and experiment operations and crew activities are being cataloged. The magnitudes of such disturbances can be as much as 0.01 g, but are rarely sustained for more than a fraction of a second and tend to vary greatly in orientation. It is found that the recorded frequency components of the SL3 disturbances do not exceed tolerance limits determined from modeling for a selected experiment set.

  2. The Continuous Electron Beam Accelerator Facility: CEBAF at the Jefferson Laboratory

    SciTech Connect

    Leemann, Chrisoph; Douglas, David R; Krafft, Geoffrey A

    2001-08-01

    The Jefferson Laboratory's superconducting radiofrequency (srf) Continuous Electron Beam Accelerator Facility (CEBAF) provides multi-GeV continuous-wave (cw) beams for experiments at the nuclear and particle physics interface. CEBAF comprises two antiparallel linacs linked by nine recirculation beam lines for up to five passes. By the early 1990s, accelerator installation was proceeding in parallel with commissioning. By the mid-1990s, CEBAF was providing simultaneous beams at different but correlated energies up to 4 GeV to three experimental halls. By 2000, with srf development having raised the average cavity gradient up to 7.5 MV/m, energies up to nearly 6 GeV were routine, at 1-150 muA for two halls and 1-100 nA for the other. Also routine are beams of >75% polarization. Physics results have led to new questions about the quark structure of nuclei, and therefore to user demand for a planned 12 GeV upgrade. CEBAF's enabling srf technology is also being applied in other projects.

  3. LLRF System Upgrade for the SLAC Linac

    SciTech Connect

    Hong, Bo; Akre, Ron; Pacak, Vojtech; /SLAC

    2012-07-06

    The Linac Coherent Light Source (LCLS) at SLAC is in full user operation and has met the stability goals for stable lasing. The 250pC bunch can be compressed to below 100fS before passing through an undulator. In a new mode of operation a 20pC bunch is compressed to about 10fS. Experimenters are regularly using this shorter X-ray pulse and getting pristine data. The 10fS bunch has timing jitter on the order of 100fS. Physicists are requesting that the RF system achieve better stability to reduce timing jitter. Drifts in the RF system require longitudinal feedbacks to work over large ranges and errors result in reduced performance of the LCLS. A new RF system is being designed to help diagnose and reduce jitter and drift in the SLAC linac.

  4. LCLS LLRF Upgrades to the SLAC Linac

    SciTech Connect

    Akre, R.; Dowell, D.; Emma, P.; Frisch, J.; Hong, B.; Kotturi, K.; Krejcik, P.; Wu, J.; Byrd, J.; /LBL, Berkeley

    2007-10-04

    The Linac Coherent Light Source (LCLS) at SLAC will be the brightest X-ray laser in the world when it comes on line. In order to achieve the brightness a 200fS length electron bunch is passed through an undulator. To create the 200fS, 3kA bunch, a 10pS electron bunch, created from a photo cathode in an RF gun, is run off crest on the RF to set up a position to energy correlation. The bunch is then compressed by chicanes. The stability of the RF system is critical in setting up the position to energy correlation. Specifications derived from simulations require the RF system to be stable to below 200fS in several critical injector stations and the last kilometer of linac. The SLAC linac RF system is being upgraded to meet these requirements.

  5. Liquid Hydrogen Target Experience at SLAC

    SciTech Connect

    Weisend, J.G.; Boyce, R.; Candia, A.; Kaminskas, W.; Mark, J.; Racine, M.; St. Lorant, S.; Weber, T.; Arnold, R.; Bosted, P.; Carr, R.; Gao, J.; Jones, C.E.; McKeown, R.; /Caltech

    2005-08-29

    Liquid hydrogen targets have played a vital role in the physics program at SLAC for the past 40 years. These targets have ranged from small ''beer can'' targets to the 1.5 m long E158 target that was capable of absorbing up to 800 W without any significant density changes. Successful use of these targets has required the development of thin wall designs, liquid hydrogen pumps, remote positioning and alignment systems, safety systems, control and data acquisition systems, cryogenic cooling circuits and heat exchangers. Detailed operating procedures have been created to ensure safety and operational reliability. This paper surveys the evolution of liquid hydrogen targets at SLAC and discusses advances in several of the enabling technologies that made these targets possible.

  6. Progress report on the SLAC Linear Collider

    SciTech Connect

    Rees, J.

    1986-06-01

    The SLAC Linear Collider project (SLC) is reported as being near completion. The performance specifications are tabulated both for the initial form and for eventual goals. Various parts of the SLC are described and the status of their construction is reported, including the front end electron gun and booster, the linac, damping ring, positron source, SLC arcs, and conventional facilities. 5 refs., 12 figs. (LEW)

  7. Development of a Dielectric-Loaded Accelerator Test Facility Based on an X-Band Magnicon Amplifier

    SciTech Connect

    Gold, S. H.; Fliflet, A. W.; Kinkead, A. K.; Gai, W.; Power, J. G.; Konecny, R.; Jing, C.; Tantawi, S. G.; Nantista, C. D.; Hu, Y.; Du, X.; Tang, C.; Lin, Y.; Bruce, R. W.; Bruce, R. L.; Lewis, D. III

    2006-01-03

    The Naval Research Laboratory (NRL) and Argonne National Laboratory (ANL), in collaboration with the Stanford Linear Accelerator Center (SLAC), are developing a dielectric-loaded accelerator (DLA) test facility powered by the 11.424-GHz magnicon amplifier that was developed jointly by NRL and Omega-P, Inc. Thus far, DLA structures developed by ANL have been tested at the NRL Magnicon Facility without injected electrons, including tests of alumina and magnesium calcium titanate structures at gradients up to {approx}8 MV/m. The next step is to inject electrons in order to build a compact DLA test accelerator. The Accelerator Laboratory of Tsinghua University in Beijing, China has developed a 5-MeV electron injector for the accelerator, and SLAC is developing a means to combine the two magnicon output arms, and to drive the injector and an accelerator section with separate control of the power ratio and relative phase. Also, RWBruce Associates, working with NRL, is developing a means to join ceramic tubes to produce long accelerating sections using a microwave brazing process. The installation and commissioning of the first dielectric-loaded test accelerator, including injector, DLA structure, and spectrometer, should take place within the next year.

  8. Preliminary Results of the Echo-Seeding Experiment ECHO-7 at SLAC

    SciTech Connect

    Xiang, D.; Colby, E.; Ding, Y.; Dunning, M.; Frederico, J.; Gilevich, S.; Hast, C.; Jobe, K.; McCormick, D.; Nelson, J.; Raubenheimer, T.O.; Soong, K.; Stupakov, G.; Szalata, Z.; Walz, D.; Weathersby, S.; Woodley, M.; Corlett, J.; Qiang, J.; Penn, G.; Prestemon, S.; /LBL, Berkeley /LPHE, Lausanne

    2010-06-15

    ECHO-7 is a proof-of-principle echo-enabled harmonic generation FEL experiment in the Next Linear Collider Test Accelerator (NLCTA) at SLAC. The experiment aims to generate coherent radiation at 318 nm and 227 nm, which are the 5th and 7th harmonic of the infrared seed laser. In this paper we present the preliminary results from the commissioning run of the completed experimental setup which started in April 2010.

  9. Mathematical models for the control program of the SLAC linear collider

    SciTech Connect

    Lee, M.J.; Blocker, C.; Chao, A.W.

    1981-02-01

    The operation of the SLAC two-mile linear accelerator in the single pass collider mode will be computer controlled. Mathematical models will be used in the control program to set up and restore the beam optics and to correct orbits. Some of the requirements imposed upon the on-line model calculations and the ways to satisfy these requirements will be described in this paper.

  10. Application of the National Ignition Facility distinguishable-from-background program to accelerator facilities at Lawrence Livermore National Laboratory.

    PubMed

    Packard, Eric D; Mac Kenzie, Carolyn

    2013-06-01

    Lawrence Livermore National Laboratory must control potentially activated materials and equipment in accordance with U.S. Department of Energy (DOE) Order 458.1, Radiation Protection of the Public and the Environment, which requires DOE approval of the process used to release volumetrically contaminated personal property and establishes a dose constraint of 10 µSv y(-1) (1 mrem y(-1)) for clearance of such property. The National Ignition Facility at Lawrence Livermore National Laboratory developed a technical basis document and protocol for determining the radiological status of property that is potentially activated from exposure to neutron radiation produced via fusion of tritium and deuterium. The technical basis included assessment of the neutron energy, the type of materials potentially exposed and the likely activation products, and the sensitivity of radiation detectors used to survey the property. This paper evaluates the National Ignition Facility technical basis document for applicability to the release of property from Lawrence Livermore National Laboratory's various accelerator facilities considering the different types of particles accelerated, radiations produced, and resultant activation products. Extensive process knowledge regarding the accelerators' operations, accompanied by years of routine surveys, provides an excellent characterization of these facilities. Activation studies conducted at the Stanford Linear Accelerator and the High Energy Accelerator Research Organization in Japan corroborate that the long-lived radionuclides produced at accelerator facilities are of the same variety produced at the National Ignition Facility. Consequently, Lawrence Livermore National Laboratory concludes that the release protocol developed for the National Ignition Facility can be used appropriately at all its accelerator facilities. PMID:23629069

  11. SLAC collider injector, RF-drive synchronization and trigger electronics, and 15-AMP thermionic-gun development

    SciTech Connect

    Koontz, R.; Miller, R.; McKinney, T.; Wilmunder, A.

    1981-02-01

    The rf drive system for the Collider Injector Development (EL CID) including laser timing, subharmonic buncher drive and phasing, and accelerator rf drive is described. The rf synchronized master trigger generation scheme for the collider is outlined. Also, a 15 amp peak, 200 kV short pulse gun being developed at SLAC as a backup to the Sinclair laser gun is described.

  12. Physico-Mechanical Characteristics of Freeze-Thaw Weathered Gneiss based on Accelerated Laboratory Experiments

    NASA Astrophysics Data System (ADS)

    Um, J. G.

    2014-12-01

    An experimental study of physical weathering was performed on fresh and slightly weathered gneiss samples from the Wonju area of South Korea. The study investigated changes in the physico-mechanical properties of these samples during accelerated laboratory-based weathering, including analyses of microfracture formation. The deteriorated samples used in the study were subjected to 100-150 freeze-thaw cycles, with index properties and microfracture geometries measured between each cycle. Each complete freeze-thaw cycle lasted 24 hours, and consisted of 2 hours of saturation in a vacuum chamber, 8 hours of freezing at -21°C ±1°C, and 14 hours of thawing at room temperature. Specific gravity and seismic velocity values were negatively correlated with the number of freeze-thaw cycles, whereas absorption values tended to increase. The amount of deterioration of the rock samples was dependent on the degree of weathering of the rock prior to the start of the analysis. Absorption, specific gravity, and seismic velocity values can be used to infer the amount of physical weathering experienced by a gneiss in the study area. The sizes and density of microfracture in the rock specimens varied with the number of freeze-thaw cycles. It was found that box fractal dimensions can be used to quantify the formation and propagation of microfracture in the samples. In addition, these box fractal dimensions can be used as a weathering index for the mid- and long-term prediction of rock weathering. The present results indicate that accelerated-weathering analysis can provide a detailed overview of the weathering characteristics of deteriorated rocks.

  13. Development of a 20 MeV Dielectric-Loaded Test Accelerator

    SciTech Connect

    Gold, S.H.; Kinkead, A.K.; Gai, W.; Power, J.G.; Konecny, R.; Jing, C.; Long, J.; Tantawi, S.G.; Nantista, C.D.; Fliflet, A.W.; Lombardi, M.; Lewis, D.; Bruce, R.W.; /Unlisted

    2007-04-13

    This paper presents a progress report on a joint project by the Naval Research Laboratory (NRL) and Argonne National Laboratory (ANL), in collaboration with the Stanford Linear Accelerator Center (SLAC), to develop a dielectric-loaded test accelerator in the magnicon facility at NRL. The accelerator will be powered by an experimental 11.424-GHz magnicon amplifier that presently produces 25 MW of output power in a {approx}250-ns pulse at up to 10 Hz. The accelerator will include a 5-MeV electron injector originally developed at the Tsinghua University in Beijing, China, and can incorporate DLA structures up to 0.5 m in length. The DLA structures are being developed by ANL, and shorter test structures fabricated from a variety of dielectric materials have undergone testing at NRL at gradients up to {approx}8 MV/m. SLAC has developed components to distribute the power from the two magnicon output arms to the injector and to the DLA accelerating structure with separate control of the power ratio and relative phase. RWBruce Associates, Inc., working with NRL, has investigated means to join short ceramic sections into a continuous accelerator tube by a brazing process using an intense 83-GHz beam. The installation and testing of the first dielectric-loaded test accelerator, including injector, DLA test structure, and spectrometer, should take place within the next year.

  14. Development of a 20 MeV Dielectric-Loaded Test Accelerator

    SciTech Connect

    Gold, Steven H.; Fliflet, Arne W.; Lombardi, Marcie; Kinkead, Allen K.; Gai, Wei; Power, John G.; Konecny, Richard; Long, Jidong; Jing, Chunguang; Tantawi, Sami G.; Nantista, Christopher D.; Bruce, Ralph W.; Lewis, David III

    2006-11-27

    This paper presents a progress report on a joint project by the Naval Research Laboratory (NRL) and Argonne National Laboratory (ANL), in collaboration with the Stanford Linear Accelerator Center (SLAC), to develop a dielectric-loaded test accelerator in the magnicon facility at NRL. The accelerator will be powered by an experimental 11.424-GHz magnicon amplifier that presently produces 25 MW of output power in a {approx}250-ns pulse at up to 10 Hz. The accelerator will include a 5-MeV electron injector originally developed at the Tsinghua University in Beijing, China, and can incorporate DLA structures up to 0.5 m in length. The DLA structures are being developed by ANL, and shorter test structures fabricated from a variety of dielectric materials have undergone testing at NRL at gradients up to {approx}8 MV/m. SLAC has developed components to distribute the power from the two magnicon output arms to the injector and to the DLA accelerating structure with separate control of the power ratio and relative phase. RWBruce Associates, Inc., working with NRL, has investigated means to join short ceramic sections into a continuous accelerator tube by a brazing process using an intense 83-GHz beam. The installation and testing of the first dielectric-loaded test accelerator, including injector, DLA test structure, and spectrometer, should take place within the next year.

  15. Linear induction accelerators at the Los Alamos National Laboratory DARHT facility

    SciTech Connect

    Nath, Subrata

    2010-09-07

    The Dual-Axis Radiographic Hydrodynamic Test Facility (DARHT) at Los Alamos National Laboratory consists of two linear induction accelerators at right angles to each other. The First Axis, operating since 1999, produces a nominal 20-MeV, 2-kA single beam-pulse with 60-nsec width. In contrast, the DARHT Second Axis, operating since 2008, produces up to four pulses in a variable pulse format by slicing micro-pulses out of a longer {approx}1.6-microseconds (flat-top) pulse of nominal beam-energy and -current of 17 MeV and 2 kA respectively. Bremsstrahlung x-rays, shining on a hydro-dynamical experimental device, are produced by focusing the electron beam-pulses onto a high-Z target. Variable pulse-formats allow for adjustment of the pulse-to-pulse doses to record a time sequence of x-ray images of the explosively driven imploding mock device. Herein, we present a sampling of the numerous physics and engineering aspects along with the current status of the fully operational dual axes capability. First successful simultaneous use of both the axes for a hydrodynamic experiment was achieved in 2009.

  16. UCLA accelerator research & development. Progress report

    SciTech Connect

    1997-09-01

    This report discusses work on advanced accelerators and beam dynamics at ANL, BNL, SLAC, UCLA and Pulse Sciences Incorporated. Discussed in this report are the following concepts: Wakefield acceleration studies; plasma lens research; high gradient rf cavities and beam dynamics studies at the Brookhaven accelerator test facility; rf pulse compression development; and buncher systems for high gradient accelerator and relativistic klystron applications.

  17. The SLAC Comparator for the Calibration of Digital Leveling Equipment

    SciTech Connect

    Gassner, G.L.; Ruland, R.E.; /SLAC

    2006-11-07

    At SLAC digital levels are used for precise leveling, both for setting out and monitoring. A very high precision of 30 {micro}m is required, which can only be achieved by regularly calibrating the leveling equipment. The calibration facility is also used for detailed investigations to refine the SLAC leveling procedure. In this paper the setup of the SLAC vertical comparator is described. In order to also perform traditional staff calibration a CCD camera was integrated into the SLAC comparator. Finally an overview of further investigations of our leveling equipment is presented.

  18. Survey and Alignment of SLAC's B Factory

    SciTech Connect

    Pietryka, Matthew J.; Gaydosh, Michael L.; /SLAC

    2011-09-08

    The survey and alignment of SLAC's B-factory injector and high energy ring will be complete in March 1997. Modern digital electronic surveying tools are contributing to new, efficient alignment procedures. A laser tracker was used to fiducialize almost 300 quadrupole magnets. Digital levels were used to pre-set base plate elevations. Theodolites with very accurate co-axial distance meters were used for everything from layout to 3D magnet positioning to network surveys, all in free stationing mode. A number of procedures and measurement results are outlined.

  19. Intensity Effects of the FACET Beam in the SLAC Linac

    SciTech Connect

    Decker, F.-J.; Lipkowitz, N.; Sheppard, J.; White, G.R.; Wienands, U.; Woodley, M.; Yocky, G.; /SLAC

    2012-07-03

    The beam for FACET (Facility for Advanced aCcelerator Experimental Tests) at SLAC requires an energy-time correlation ('chirp') along the linac, so it can be compressed in two chicanes, one at the midpoint in sector 10 and one W-shaped chicane just before the FACET experimental area. The induced correlation has the opposite sign to the typical used for BNS damping, and therefore any orbit variations away from the center kick the tail of the beam more than the head, causing a shear in the beam and emittance growth. Any dispersion created along the linac has similar effects due to the high (>1.2% rms) energy spread necessary for compression. The initial huge emittances could be reduced by a factor of 10, but were still bigger than expected by a factor of 2-3. Normalized emittance of 3 {micro}m-rad in Sector 2 blew up to 150 {micro}m-rad in Sector 11 but could be reduced to about 6-12 {micro}m-rad, for the vertical plane although the results were not very stable. Investigating possible root causes for this, we found locations where up to 10 mm dispersion was created along the linac, which were finally verified with strong steering and up to 7 mm settling of the linac accelerator at these locations.

  20. Laboratory laser acceleration and high energy astrophysics: {gamma}-ray bursts and cosmic rays

    SciTech Connect

    Tajima, T.; Takahashi, Y.

    1998-08-20

    Recent experimental progress in laser acceleration of charged particles (electrons) and its associated processes has shown that intense electromagnetic pulses can promptly accelerate charged particles to high energies and that their energy spectrum is quite hard. On the other hand some of the high energy astrophysical phenomena such as extremely high energy cosmic rays and energetic components of {gamma}-ray bursts cry for new physical mechanisms for promptly accelerating particles to high energies. The authors suggest that the basic physics involved in laser acceleration experiments sheds light on some of the underlying mechanisms and their energy spectral characteristics of the promptly accelerated particles in these high energy astrophysical phenomena.

  1. Earthquake Dynamics in Laboratory Model and Simulation - Accelerated Creep as Precursor of Instabilities

    NASA Astrophysics Data System (ADS)

    Grzemba, B.; Popov, V. L.; Starcevic, J.; Popov, M.

    2012-04-01

    Shallow earthquakes can be considered as a result of tribological instabilities, so called stick-slip behaviour [1,2], meaning that sudden slip occurs at already existing rupture zones. From a contact mechanics point of view it is clear, that no motion can arise completely sudden, the material will always creep in an existing contact in the load direction before breaking loose. If there is a measureable creep before the instability, this could serve as a precursor. To examine this theory in detail, we built up an elementary laboratory model with pronounced stick-slip behaviour. Different material pairings, such as steel-steel, steel-glass and marble-granite, were analysed at different driving force rates. The displacement was measured with a resolution of 8 nm. We were able to show that a measureable accelerated creep precedes the instability. Near the instability, this creep is sufficiently regular to serve as a basis for a highly accurate prediction of the onset of macroscopic slip [3]. In our model a prediction is possible within the last few percents of the preceding stick time. We are hopeful to extend this period. Furthermore, we showed that the slow creep as well as the fast slip can be described very well by the Dieterich-Ruina-friction law, if we include the contribution of local contact rigidity. The simulation meets the experimental curves over five orders of magnitude. This friction law was originally formulated for rocks [4,5] and takes into account the dependency of the coefficient of friction on the sliding velocity and on the contact history. The simulations using the Dieterich-Ruina-friction law back up the observation of a universal behaviour of the creep's acceleration. We are working on several extensions of our model to more dimensions in order to move closer towards representing a full three-dimensional continuum. The first step will be an extension to two degrees of freedom to analyse the interdependencies of the instabilities. We also plan

  2. Laboratory and accelerator test of the charge particle detectors for a satellite instrument "STEP-F"

    NASA Astrophysics Data System (ADS)

    Dudnik, O. V.; Goka, T.; Matsumoto, H.; Fujii, M.; Golovash, O. S.; Malykhina, T. V.

    2003-04-01

    The spectrometer-telescope "STEP-F" is aimed for the registration of high-energy charged particle fluxes in the near Earth space. It is planned to install the instrument on board of Russian spacecraft "Coronas-Photon" to study solar cosmic rays and dynamics of the Earth' radiation belts. Its detector system consists of two position-sensitive silicon matrices to determine the direction of the primary particles and two layers of the scintillation detectors that serve for the energy determining of these particles. First laboratory tests of detectors were made with the help of various radioactive sources and imitating signals. Radiophysical characteristics as well as temperature dependence of the energy resolution for silicon matrix element and CsI(Tl) scintillation detector are presented. In order to check the reaction extent of the detectors in high energy range the tests was carried out on the ion cyclotron accelerator of the Institute of Physical and Chemical Research (RIKEN, Japan). We have used a-particle and hydrogen ion H2 beams to determine the response level and real energy range of particles registered by each layer of detectors. Simultaneously a computer simulation of deposited energies and stopping ranges for electrons, protons and alpha-particles has been done. The simulation by Monte Carlo method is made using the Cern GEANT4.2 Code under OS LINUX6.2. The experimental data obtained is in well agreement with results of Monte-Carlo simulation. It has been found, both experimentally and by simulation, that the signals coming from neighboring elements of the position-sensitive silicon matrix are not affected by secondary particles. In particular, the number of albedo secondary particles generated in the scintillator is rather small as compared to the primary particles, so that secondaries do not significantly contribute to the total intensity of recorded primary particles.

  3. SLAC three-body partial wave analysis system

    SciTech Connect

    Aston, D.; Lasinski, T.A.; Sinervo, P.K.

    1985-10-01

    We present a heuristic description of the SLAC-LBL three-meson partial wave model, and describe how we have implemented it at SLAC. The discussion details the assumptions of the model and the analysis, and emphasizes the methods we have used to prepare and fit the data. 28 refs., 12 figs., 1 tab.

  4. Radiation Safety System for Stanford Synchrotron Radiation Laboratory

    SciTech Connect

    Liu, J

    2004-03-12

    Radiation Safety System (RSS) at the Stanford Synchrotron Radiation Laboratory is summarized and reviewed. The RSS, which is designed to protect people from prompt radiation hazards from accelerator operation, consists of the Access Control System (ACS) and the Beam Containment System (BCS). The ACS prevents people from being exposed to the lethal radiation level inside the shielding housing (called a PPS area at SLAC). The ACS for a PPS area consists of the shielding housing, beam inhibiting devices, and a standard entry module at each entrance. The BCS protects people from the prompt radiation hazards outside a PPS area under both normal and abnormal beam loss situations. The BCS consists of the active power (current/energy) limiting devices, beam stoppers, shielding, and an active radiation monitor system. The policies and practices in setting up the RSS at SLAC are illustrated.

  5. Linac Coherent Light Source (LCLS) at 2--4 nm using the SLAC linac

    SciTech Connect

    Seeman, J.T.; Bane, K.; Boyce, R.; Loew, G.; Morton, P.; Nuhn, H.D.; Paterson, J.; Pianetta, P.; Raubenheimer, T.; Tatchyn, R.; Vylet, V.; Winick, H.; Pellegrini, C.; Rosenzweig, J.; Travish, G.; Prosnitz, D.; Scharlemann, E.T.; Halbach, K.; Kim, K.J.; Xie, M.

    1993-08-01

    The authors describe the possible use of the SLAC linac to drive a unique, powerful, short wavelength Linac Coherent Light Source (LCLS). Using the FEL principle, lasing is achieved in a single pass of a high peak current electron beam through a long undulator by self-amplified-spontaneous-emission (SASE). The main components are a high-brightness electron RF gun with a photocathode, two electron bunch length compressors, the existing SLAC linac, beam diagnostics, and a long undulator combined with a FODO quadrupole focusing system. The RF gun, to be installed about 1 km from the end of the SLAC linac, would produce a single bunch of 6 x 10{sup 9} electrons with an invariant emittance of about 3 mm-mrad and a bunch length of about 500 {mu}m. That bunch is then accelerated to 100 MeV and compressed to a length of about 200 {mu}m. The main SLAC linac accelerates the bunch to 2 GeV were a second bunch compressor reduces the length to 30--40 {mu}m and produces a peak current of 2--3 kA. The bunch is then accelerated to 7--8 GeV and transported to a 50--70 m long undulator. Using electrons below 8 GeV, the undulator could operate at wavelengths down to 2 nm, producing about 10 GW peak power in sub-ps light pulses. At a linac repetition rate of 120 Hz, the average power is about 1 W. Linac operation at lower beam energies provides longer wavelength radiation. After the undulator, the beam is deposited in a dump. The LCLS light pulses are then distributed to multiple user stations using grazing incident mirrors. Length compression, emittance control, phase stability, FEL design criteria, and parameter tolerances are discussed. A demonstration experiment is also described which uses the SLAC linac and (possibly) the PALADIN undulator to study SASE to power saturation at wavelengths of 40--360 nm.

  6. LLNL/UC (Lawrence Livermore National Laboratory)/(University of California) AMS (accelerator mass spectrometry) facility and research program

    SciTech Connect

    Davis, J.C.; Proctor, I.D.; Southon, J.R.; Caffee, M.W.; Heikkinen, D.W.; Roberts, M.L.; Moore, T.L.; Turteltaub, K.W.; Nelson, D.E.; Loyd, D.H.; Vogel, J.S.

    1990-04-18

    The Lawrence Livermore National Laboratory (LLNL) and the University of California (UC) now have in operation a large AMS spectrometer built as part of a new multiuser laboratory centered on an FN tandem. AMS measurements are expected to use half of the beam time of the accelerator. LLNL use of AMS is in research on consequences of energy usage. Examples include global warming, geophysical site characterization, radiation biology and dosimetry, and study of mutagenic and carcinogenic processes. UC research activities are in clinical applications, archaeology and anthropology, oceanography, and geophysical and geochemical research. Access is also possible for researchers outside the UC system. The technological focus of the laboratory is on achieving high rates of sample through-put, unattended operation, and advances in sample preparation methods. Because of the expected growth in the research programs and the other obligations of the present accelerator, we are designing a follow-on dedicated facility for only AMS and microprobe analysis that will contain at least two accelerators with multiple spectrometers. 10 refs., 1 fig.

  7. ILC Linac R&D at SLAC

    SciTech Connect

    Adolphsen, C.; /SLAC

    2006-08-09

    Since the ITRP recommendation in August 2004 to use superconducting rf technology for a next generation linear collider, the former NLC Group at SLAC has been actively pursuing a broad range of R&D for this collider (the ILC). In this paper, the programs concerning linac technology are reviewed. Current activities include the development of a Marx-style modulator and a 10 MW sheet-beam klystron, operation of an L-band (1.3 GHz) rf source using an SNS HVCM modulator and commercial klystrons, design of a more efficient and less costly rf distribution system, construction of a coupler component test stand, fabrication of a prototype positron capture cavity, beam tests of prototype S-band linac beam position monitors and preparations for magnetic center stability measurements of a prototype SC linac quad.

  8. Cerenkov ring imaging detector development at SLAC

    SciTech Connect

    Williams, S.H.

    1984-06-01

    The imaging of Cerenkov light on to photosensitive detectors promises to be a powerful technique for identifying particles in colliding beam spectrometers. Toward this end two and three dimensional imaging photon detectors are being developed at SLAC. The present techniques involve photon conversion using easily ionized exotic chemicals like tetrakisdimethyl-amino-ethylene (TMAE) in a drift and amplifying gas mixture of methane and isobutane. Single photoelectrons from Cerenkov light are currently being drifted 20 cm and a new device under study will be used to study drifting up to 80 cm along a magnetic field. A short description of a large device currently being designed for the SLD spectrometer at the Stanford Linear Collider will be given.

  9. Lattice Design for ERL Options at SLAC

    SciTech Connect

    Nosochkov, Yuri; Cai, Yunhai; Huang, Xiaobiao; Wang, Min-Huey; /SLAC

    2011-06-02

    SLAC is investigating long-range options for building a high performance light source machine while reusing the existing linac and PEP-II tunnels. One previously studied option is the PEP-X low emittance storage ring. The alternative option is based on a superconducting Energy Recovery Linac (ERL) and the PEP-X design. The ERL advantages are the low beam emittance, short bunch length and small energy spread leading to better qualities of the X-ray beams. Two ERL configurations differed by the location of the linac have been studied. Details of the lattice design and the results of beam transport simulations with the coherent synchrotron radiation effects are presented.

  10. Microprocessors in physics experiments at SLAC

    SciTech Connect

    Rochester, L.S.

    1981-04-01

    The increasing size and complexity of high energy physics experiments is changing the way data are collected. To implement a trigger or event filter requires complex logic which may have to be modified as the experiment proceeds. Simply to monitor a detector, large amounts of data must be processed on line. The use of microprocessors or other programmable devices can help to achieve these ends flexibly and economically. At SLAC, a number of microprocessor-based systems have been built and are in use in experimental setups, and others are now being developed. This talk is a review of existing systems and their use in experiments, and of developments in progress and future plans.

  11. 100 MW klystron development at SLAC

    SciTech Connect

    Vlieks, A.E.; Callin, R.S.; Caryotakis, G.; Fant, K.S.; Fowkes, W.R.; Lee, T.G.; Wright, E.L.

    1991-05-01

    A klystron designed to operate at 11.4 GHz and 440 kV is presently SLAC's strongest rf power source candidate for the Next Linear Collider. It is expected to provide 100 MW of rf power with a pulse width of 1 microsecond. Many of the conventional tube technologies are being pushed to their limits. High electron beam power densities, rf electric gradients in cavity gaps and stresses on the ceramic rf output windows are among the most severe problems to be dealt with. This paper describes progress in the development of this device including results from single and double gap output cavities and various styles of rf output windows. 6 refs., 3 figs., 1 tab.

  12. A portable accelerator control toolkit

    SciTech Connect

    Watson, W.A. III

    1997-06-01

    In recent years, the expense of creating good control software has led to a number of collaborative efforts among laboratories to share this cost. The EPICS collaboration is a particularly successful example of this trend. More recently another collaborative effort has addressed the need for sophisticated high level software, including model driven accelerator controls. This work builds upon the CDEV (Common DEVice) software framework, which provides a generic abstraction of a control system, and maps that abstraction onto a number of site-specific control systems including EPICS, the SLAC control system, CERN/PS and others. In principle, it is now possible to create portable accelerator control applications which have no knowledge of the underlying and site-specific control system. Applications based on CDEV now provide a growing suite of tools for accelerator operations, including general purpose displays, an on-line accelerator model, beamline steering, machine status displays incorporating both hardware and model information (such as beam positions overlaid with beta functions) and more. A survey of CDEV compatible portable applications will be presented, as well as plans for future development.

  13. Ground motions and its effects in accelerator design

    SciTech Connect

    Fischer, G.E.

    1984-07-01

    This lecture includes a discussion of types of motion, frequencies of interest, measurements at SLAC, some general comments regarding local sources of ground motion at SLAC, and steps that can be taken to minimize the effects of ground motion on accelerators. (GHT)

  14. A Massively Parallel Solver for the Mechanical Harmonic Analysis of Accelerator Cavities

    SciTech Connect

    O. Kononenko

    2015-02-17

    ACE3P is a 3D massively parallel simulation suite that developed at SLAC National Accelerator Laboratory that can perform coupled electromagnetic, thermal and mechanical study. Effectively utilizing supercomputer resources, ACE3P has become a key simulation tool for particle accelerator R and D. A new frequency domain solver to perform mechanical harmonic response analysis of accelerator components is developed within the existing parallel framework. This solver is designed to determine the frequency response of the mechanical system to external harmonic excitations for time-efficient accurate analysis of the large-scale problems. Coupled with the ACE3P electromagnetic modules, this capability complements a set of multi-physics tools for a comprehensive study of microphonics in superconducting accelerating cavities in order to understand the RF response and feedback requirements for the operational reliability of a particle accelerator. (auth)

  15. Microwave measurements of azimuthal asymmetries in accelerating fields of disk-loaded waveguides

    SciTech Connect

    Loew, G.A.; Deruyter, H.; Defa, W.

    1983-03-01

    This paper presents microwave measurements of azimuthal asymmetries in the accelerating fields of the SLAC disk-loaded waveguide. These field asymmetries lead to rf phase-dependent beam steering which can be detrimental to operation of linear accelerators in general and of the SLAC Linear Collider in particular.

  16. COAXIAL TWO-CHANNEL DIELECTRIC WAKE FIELD ACCELERATOR

    SciTech Connect

    Hirshfield, Jay L.

    2013-04-30

    Theory, computations, and experimental apparatus are presented that describe and are intended to confirm novel properties of a coaxial two-channel dielectric wake field accelerator. In this configuration, an annular drive beam in the outer coaxial channel excites multimode wakefields which, in the inner channel, can accelerate a test beam to an energy much higher than the energy of the drive beam. This high transformer ratio is the result of judicious choice of the dielectric structure parameters, and of the phase separation between drive bunches and test bunches. A structure with cm-scale wakefields has been build for tests at the Argonne Wakefield Accelerator Laboratory, and a structure with mm-scale wakefields has been built for tests at the SLAC FACET facility. Both tests await scheduling by the respective facilities.

  17. Do sediment type and test durations affect results of laboratory-based, accelerated testing studies of permeable pavement clogging?

    PubMed

    Nichols, Peter W B; White, Richard; Lucke, Terry

    2015-04-01

    Previous studies have attempted to quantify the clogging processes of Permeable Interlocking Concrete Pavers (PICPs) using accelerated testing methods. However, the results have been variable. This study investigated the effects that three different sediment types (natural and silica), and different simulated rainfall intensities, and testing durations had on the observed clogging processes (and measured surface infiltration rates) of laboratory-based, accelerated PICP testing studies. Results showed that accelerated simulated laboratory testing results are highly dependent on the type, and size of sediment used in the experiments. For example, when using real stormwater sediment up to 1.18 mm in size, the results showed that neither testing duration, nor stormwater application rate had any significant effect on PICP clogging. However, the study clearly showed that shorter testing durations generally increased clogging and reduced the surface infiltration rates of the models when artificial silica sediment was used. Longer testing durations also generally increased clogging of the models when using fine sediment (<300 μm). Results from this study will help researchers and designers better anticipate when and why PICPs are susceptible to clogging, reduce maintenance and extend the useful life of these increasingly common stormwater best management practices. PMID:25618819

  18. The Role of Research Universities in Helping Solve our Energy Challenges: A Case Study at Stanford and SLAC (2011 EFRC Summit)

    ScienceCinema

    Hennessey, John (President, Stanford University)

    2012-03-14

    The first speaker in the 2011 EFRC Summit session titled "Leading Perspectives in Energy Research" was John Hennessey, President of Stanford University. He discussed the important role that the academic world plays as a partner in innovative energy research by presenting a case study involving Stanford and SLAC. The 2011 EFRC Summit and Forum brought together the EFRC community and science and policy leaders from universities, national laboratories, industry and government to discuss "Science for our Nation's Energy Future." In August 2009, the Office of Science established 46 Energy Frontier Research Centers. The EFRCs are collaborative research efforts intended to accelerate high-risk, high-reward fundamental research, the scientific basis for transformative energy technologies of the future. These Centers involve universities, national laboratories, nonprofit organizations, and for-profit firms, singly or in partnerships, selected by scientific peer review. They are funded at $2 to $5 million per year for a total planned DOE commitment of $777 million over the initial five-year award period, pending Congressional appropriations. These integrated, multi-investigator Centers are conducting fundamental research focusing on one or more of several ?grand challenges? and use-inspired ?basic research needs? recently identified in major strategic planning efforts by the scientific community. The purpose of the EFRCs is to integrate the talents and expertise of leading scientists in a setting designed to accelerate research that transforms the future of energy and the environment.

  19. The MIT Accelerator Laboratory for Diagnostic Development for OMEGA, Z and the NIF

    NASA Astrophysics Data System (ADS)

    Petrasso, R.; Gatu Johnson, M.; Armstrong, E.; Orozco, D.; Rinderknecht, H. G.; Rojas Herrera, J.; Rosenberg, M.; Sio, H.; Zylstra, A.; Frenje, J.; Li, C. K.; Seguin, F. H.; Hahn, K.; Jones, B.; Ruiz, C. L.; Sangster, T. C.

    2014-10-01

    The MIT Linear Electrostatic Ion Accelerator generates D-D and D-3He fusion products, which are used for development of nuclear diagnostics for OMEGA, Z, and the NIF. Fusion reaction rates around 106 s-1 are routinely achieved with this accelerator, and fluence and energy of the fusion products are accurately characterized. Diagnostics developed and calibrated at this facility include CR-39 based charged-particle spectrometers, neutron detectors, and the particle Time-Of-Flight (pTOF) CVD-diamond-based bang time detector. The accelerator is also a vital tool in the education of graduate and undergraduate students at MIT. This work was supported in part by SNL, DOE, LLE and LLNL.

  20. Design of an Optical Diffraction Radiation Beam Size Monitor at SLAC FETB

    SciTech Connect

    Fukui, Yasuo; Cline, D.; Zhou, F.; Tobiyama, M.; Urakawa, J.; Bolton, P.R.; Ross, M.C.; Hamatsu, R.; Karataev, P.V.; Muto, T.; Aryshev, A.S.; Naumenko, G.A.; Potylitsyn, A.P.; /UCLA /KEK, Tsukuba /SLAC /Tokyo Metropolitan U., Math. Dept. /Tomsk Polytechnic U.

    2008-03-17

    We design a single bunch transverse beam size monitor which will be tested to measure the 28.5 GeV electron/positron beam at the SLAC FFTB beam line. The beam size monitor uses the CCD images of the interference pattern of the optical diffraction radiation from two slit edges which are placed close to the beam path. In this method, destruction of the accelerated electron/positron beam bunches due to the beam size monitoring is negligible, which is vital to the operation of the Linear Collider project.

  1. Progress in L-Band Power Distribution System R&D at SLAC

    SciTech Connect

    Nantista, Christopher; Adolphsen, Chris; Wang, Faya; /SLAC

    2008-10-20

    We report on the L-band RF power distribution system (PDS) developed at SLAC for Fermilab's NML superconducting test accelerator facility. The makeup of the system, which allows tailoring of the power distribution to cavities by pairs, is briefly described. Cold test measurements of the system and the results of high power processing are presented. We also investigate the feasibility of eliminating the expensive, lossy circulators from the PDS by pair-feeding cavities through custom 3-dB hybrids. A computational model is used to simulate the impact on cavity field stability due to the reduced cavity-to-cavity isolation.

  2. Upgrade of the SLAC SLED II Pulse Compression System Based on Recent High Power Tests

    SciTech Connect

    Vlieks, A.E.; Fowkes, W.R.; Loewen, R.J.; Tantawi, S.G.; /SLAC

    2011-09-06

    In the Next Linear Collider (NLC) it is expected that the high power rf components be able to handle peak power levels in excess of 400 MW. We present recent results of high power tests designed to investigate the RF breakdown limits of the X-band pulse compression system used at SLAC. (SLED-II). Results of these tests show that both the TE{sub 01}-TE{sub 10} mode converter and the 4-port hybrid have a maximum useful power limit of 220-250 MW. Based on these tests, modifications of these components have been undertaken to improve their peak field handling capability. Results of these modifications will be presented. As part of an international effort to develop a new 0.5-1.5 TeV electron-positron linear collider for the 21st century, SLAC has been working towards a design, referred to as 'The Next Linear Collider' (NLC), which will operate at 11.424 GHz and utilize 50-75 MW klystrons as rf power sources. One of the major challenges in this design, or any other design, is how to generate and efficiently transport extremely high rf power from a source to an accelerator structure. SLAC has been investigating various methods of 'pulse compressing' a relatively wide rf pulse ({ge} 1 {mu}s) from a klystron into a narrower, but more intense, pulse. Currently a SLED-II pulse compression scheme is being used at SLAC in the NLC Test Accelerator (NLCTA) and in the Accelerator Structures Test Area (ASTA) to provide high rf power for accelerator and component testing. In ASTA, a 1.05 {mu}s pulse from a 50 MW klystron was successfully pulse compressed to 205 MW with a pulse width of 150 ns. Since operation in NLC will require generating and transporting rf power in excess of 400 MW it was decided to test the breakdown limits of the SLED-II rf components in ASTA with rf power up to the maximum available of 400 MW. This required the combining of power from two 50 MW klystrons and feeding the summed power into the SLED-II pulse compressor. Results from this experiment demonstrated

  3. Relativistic klystron research at SLAC and LLNL

    SciTech Connect

    Allen, M.A.; Callin, R.S.; Deruyter, H.; Eppley, K.R.; Fowkes, W.R.; Herrmannsfeldt, W.B.; Higo, T.; Hoag, H.A.; Lavine, T.L.; Lee, T.G.; Loew, G.A.; Miller, R.H.; Morton, P.L.; Palmer, R.B.; Paterson, J.M.; Ruth, R.D.; Schwarz, H.D.; Takeuchi, Y.; Vlieks, A.E.; Wang, J.W.; Wilson, P.B.; Hopkins, D.B.; Sessler, A.M.; Barletta, W.A.; Birx, D.L.; Boyd, J.K.; Houck, T.; Westenskow, G.A.; Yu, S.S.

    1988-06-01

    We are developing relativistic klystrons as a power source for high gradient accelerator applications such as large linear electron-positron colliders and compact accelerators. We have attained 200 MW peak power at 11.4 GHz from a relativistic klystron, and 140 MV/m longitudinal gradient in a short 11.4 GHz accelerator section. We report here briefly on our experiments so far. 5 refs., 1 fig., 1 tab.

  4. Emittance Studies of the BNL/SLAC/UCLA 1.6 Cell Photocathode RF Gun

    SciTech Connect

    Palmer, D.T.; Wang, X.J.; Miller, R.H.; Babzien, M.; Ben-Zvi, I.; Pellegrini, C.; Sheehan, J.; Skaritka, J.; Winick, H.; Woodle, M.; Yakimenko, V.; /Brookhaven

    2011-09-09

    The symmetrized 1.6 cell S-band photocathode gun developed by the BNL/SLAC/UCLA collaboration is in operation at the Brookhaven Accelerator Test Facility (ATF). A novel emittance compensation solenoid magnet has also been designed, built and is in operation at the ATF. These two subsystems form an emittance compensated photoinjector used for beam dynamics, advanced acceleration and free electron laser experiments at the ATF. The highest acceleration field achieved on the copper cathode is 150 MV/m, and the guns normal operating field is 130 MV/m. The maximum rf pulse length is 3 {mu}s. The transverse emittance of the photoelectron beam were measured for various injection parameters. The 1 nC emittance results are presented along with electron bunch length measurements that indicated that at above the 400 pC, space charge bunch lengthening is occurring. The thermal emittance, {epsilon}{sub o}, of the copper cathode has been measured.

  5. Future Development Of The Flerov Laboratory Accelerator Complex (Project DRIBs-III)

    NASA Astrophysics Data System (ADS)

    Gulbekian, G. G.; Dmitriev, S. N.; Itkis, M. G.; Oganessian, Yu. Ts.; Popeko, A. G.

    2010-04-01

    Future development of the FLNR accelerator complex (project DRIBs-III) includes modernization of existing cyclotrons, construction of a new experimental hall, creation of a new high current cyclotron and of next generation experimental set-ups. Realization of the project is planned for 2010-2016.

  6. Search milli-charged particles at SLAC

    SciTech Connect

    Langeveld, W.G.J.

    1997-01-01

    Particles with electric charge q {triple_bond} Qe {le} 10{sup -3} e and masses in the range 1-1000 MeV/c{sup 2} are not excluded by present experiments or by astrophysical or cosmological arguments. A beam dump experiment uniquely suited to the detection of such {open_quotes}milli-charged{close_quotes} particles has been carried out at SLAC, utilizing the short-duration pulses of the SLC electron beam to establish a tight coincidence window for the signal. The detector, a large scintillation counter sensitive to very small energy depositions, provided much greater sensitivity than previous searches. Analysis of the data leads to the exclusion of a substantial portion of the charge-mass plane. In this report, a preliminary mass-dependent upper limit is presented for the charge of milli-charged particles, ranging from Q = 1.7 x 10{sup -5} at milli-charged particle mass 0.1 MeV/c{sup 2} to Q = 9.5 x 10{sup -4} at 100 MeV/c{sup 2}.

  7. Bulk ion acceleration and particle heating during magnetic reconnection in a laboratory plasma

    SciTech Connect

    Yoo, Jongsoo; Yamada, Masaaki; Ji, Hantao; Jara-Almonte, Jonathan; Myers, Clayton E.

    2014-05-15

    Bulk ion acceleration and particle heating during magnetic reconnection are studied in the collisionless plasma of the Magnetic Reconnection Experiment (MRX). The plasma is in the two-fluid regime, where the motion of the ions is decoupled from that of the electrons within the ion diffusion region. The reconnection process studied here is quasi-symmetric since plasma parameters such as the magnitude of the reconnecting magnetic field, the plasma density, and temperature are compatible on each side of the current sheet. Our experimental data show that the in-plane (Hall) electric field plays a key role in ion heating and acceleration. The electrostatic potential that produces the in-plane electric field is established by electrons that are accelerated near the electron diffusion region. The in-plane profile of this electrostatic potential shows a “well” structure along the direction normal to the reconnection current sheet. This well becomes deeper and wider downstream as its boundary expands along the separatrices where the in-plane electric field is strongest. Since the in-plane electric field is 3–4 times larger than the out-of-plane reconnection electric field, it is the primary source of energy for the unmagnetized ions. With regard to ion acceleration, the Hall electric field causes ions near separatrices to be ballistically accelerated toward the outflow direction. Ion heating occurs as the accelerated ions travel into the high pressure downstream region. This downstream ion heating cannot be explained by classical, unmagnetized transport theory; instead, we conclude that ions are heated by re-magnetization of ions in the reconnection exhaust and collisions. Two-dimensional (2-D) simulations with the global geometry similar to MRX demonstrate downstream ion thermalization by the above mechanisms. Electrons are also significantly heated during reconnection. The electron temperature sharply increases across the separatrices and peaks just outside of the

  8. Rapid acceleration leads to rapid weakening in earthquake-like laboratory experiments

    NASA Astrophysics Data System (ADS)

    Chang, J. C.; Lockner, D. A.; Reches, Z.

    2012-12-01

    We simulated the slip of a fault-patch during a large earthquake by rapidly loading an experimental, ring-shaped fault with energy stored in a spinning flywheel. The flywheel abruptly delivers a finite amount of energy by spinning the fault-patch that spontaneously dissipates the energy without operator intervention. We conducted 42 experiments on Sierra White granite (SWG) samples, and 24 experiments on Kasota dolomite (KD) samples. Each experiment starts by spinning a 225 kg disk-shaped flywheel to a prescribed angular velocity. We refer to this experiment as an "earthquake-like slip-event" (ELSE). The strength-evolution in ELSE experiments is similar to the strength-evolution proposed for earthquake models and observed in stick-slip experiments. Further, we found that ELSE experiments are similar to earthquakes in at least three ways: (1) slip driven by the release of a finite amount of stored energy; (2) pattern of fault strength evolution; and (3) seismically observed values, such as average slip, peak-velocity and rise-time. By assuming that the measured slip, D, in ELSE experiments is equivalent to the average slip during an earthquake, we found that ELSE experiments (D = 0.003-4.6 m) correspond to earthquakes in moment-magnitude range of Mw = 4-8. In ELSE experiments, the critical-slip-distance, dc, has mean values of 2.7 cm and 1.2 cm for SWG and KD, that are much shorter than the 1-10 m in steady-state classical experiments in rotary shear systems. We attribute these dc values, to ELSE loading in which the fault-patch is abruptly loaded by impact with a spinning flywheel. Under this loading, the friction-velocity relations are strikingly different from those under steady-state loading on the same rock samples with the same shear system (Reches and Lockner, Nature, 2010). We further note that the slip acceleration in ELSE evolves systematically with fault strength and wear-rate, and that the dynamic weakening is restricted to the period of intense

  9. Rapid acceleration leads to rapid weakening in earthquake-like laboratory experiments

    USGS Publications Warehouse

    Chang, Jefferson C.; Lockner, David A.; Reches, Z.

    2012-01-01

    After nucleation, a large earthquake propagates as an expanding rupture front along a fault. This front activates countless fault patches that slip by consuming energy stored in Earth’s crust. We simulated the slip of a fault patch by rapidly loading an experimental fault with energy stored in a spinning flywheel. The spontaneous evolution of strength, acceleration, and velocity indicates that our experiments are proxies of fault-patch behavior during earthquakes of moment magnitude (Mw) = 4 to 8. We show that seismically determined earthquake parameters (e.g., displacement, velocity, magnitude, or fracture energy) can be used to estimate the intensity of the energy release during an earthquake. Our experiments further indicate that high acceleration imposed by the earthquake’s rupture front quickens dynamic weakening by intense wear of the fault zone.

  10. Recent Developments on ALICE (Accelerators and Lasers In Combined Experiments) at Daresbury Laboratory

    SciTech Connect

    Saveliev, Y M; Buckley, R K; Buckley, S R; Clarke, J A; Corlett, P A; Dunning, D J; Goulden, A R; Hill, S F; Jackson, F; Jamison, S P; Jones, J K; Jones, L B; Leonard, S; McIntosh, P A; McKenzie, J W; Middleman, K J; Militsyn, B L; Moss, A J; Muratori, B D; Orrett, J F; Pattalwar, S M; Phillips, P J; Scott, D J; Seddon, E A; Shepherd, B.J.A.; Smith, S L; Thompson, N; Wheelhouse, A E; Williams, P H; Harrison, P; Holder, D J; Holder, G M; Schofield, A L; Weightman, P; Williams, R L; Laundry, D; Powers, T; Priebe, G; Surman, M

    2010-05-01

    Progress made in ALICE (Accelerators and Lasers In Combined Experiments) commissioning and a summary of the latest experimental results are presented in this paper. After an extensive work on beam loading effects in SC RF linac (booster) and linac cavities conditioning, ALICE can now operate in full energy recovery mode at the bunch charge of 40pC, the beam energy of 30MeV and train lengths of up to 100us. This improved operation of the machine resulted in generation of coherently enhanced broadband THz radiation with the energy of several tens of uJ per pulse and in successful demonstration of the Compton Backscattering x-ray source experiment. The next steps in the ALICE scientific programme are commissioning of the IR FEL and start of the research on the first non-scaling FFAG accelerator EMMA. Results from both projects will be also reported.

  11. Laboratory simulation of ion acceleration in the presence of lower hybrid waves

    NASA Astrophysics Data System (ADS)

    McWilliams, R.; Koslover, R.; Boehmer, H.; Rynn, N.

    Ion acceleration perpendicular to the geomagnetic field has been observed by satellites and rockets in the suprauroral region. Also found are broadband lower-hybrid waves, and, at higher altitudes, conical upward-flowing ion distributions. The UCI Q-machine has been used to simulate the effect of lower hybrid waves on ion acceleration. Laser induced fluorescence was used for high resolution, non-perturbing measurements of the ion velocity distribution function. The plasma consisted of a 1 m long, 5 cm diameter barium plasma of densities on the order of 1010 per cm3 contained by a 3 kG magnetic field. Substantial changes in the perpendicular ion distribution were found. Main-body ion heating occurred along with non-maxwellian tail production. Over a 10 dB change in input wave power we observed up to a factor of 3 enhancement in main-body ion temperature.

  12. Rapid Acceleration Leads to Rapid Weakening in Earthquake-Like Laboratory Experiments

    NASA Astrophysics Data System (ADS)

    Chang, J. C.; Lockner, D. A.; Reches, Z.

    2012-10-01

    After nucleation, a large earthquake propagates as an expanding rupture front along a fault. This front activates countless fault patches that slip by consuming energy stored in Earth’s crust. We simulated the slip of a fault patch by rapidly loading an experimental fault with energy stored in a spinning flywheel. The spontaneous evolution of strength, acceleration, and velocity indicates that our experiments are proxies of fault-patch behavior during earthquakes of moment magnitude (Mw) = 4 to 8. We show that seismically determined earthquake parameters (e.g., displacement, velocity, magnitude, or fracture energy) can be used to estimate the intensity of the energy release during an earthquake. Our experiments further indicate that high acceleration imposed by the earthquake’s rupture front quickens dynamic weakening by intense wear of the fault zone.

  13. Performance of the accelerator driver of Jefferson Laboratory's Free-Electron Laser

    SciTech Connect

    Bohn, C L

    1998-09-01

    The driver for Jefferson Lab's infrared free-electron laser is a superconducting, recirculating accelerator that recovers about 75% of the electron-beam energy and converts it to radiofrequency power. It is designed to lase continuous-wave at 3--6 {mu}m at kW-level power. In achieving first light, the accelerator operated straight ahead to deliver 38 MeV, 1.1 mA cw current through the wiggler for lasing at wavelengths in the vicinity of 5 {mu}m. The waste beam was then sent directly to a dump, bypassing the recirculation loop. Stable operation at power levels up to 311 W cw have thus far been achieved in this mode. The accelerator has recently recirculated up to 0.6 mA cw current with energy recovery. In this mode it has lased pulsed and cw at low-power. It remains to clean up the transport for high-power cw lasing.

  14. Particle optics and accelerator modeling software for industrial and laboratory beamline design

    NASA Astrophysics Data System (ADS)

    Gillespie, George H.; Hill, Barrey W.

    1998-04-01

    The expanding variety of accelerator applications in research and industry places increased demands upon scientists and engineers involved in developing new accelerator and beamline designs. Computer codes for particle optics simulation have always played an important role in the design process and enhanced software tools offer the promise of improved productivity for beamline designers. This paper summarizes recent work on the development of advanced graphic user interface (GUI) software components, that can be linked directly to many of the standard particle optics programs used in the accelerator community, and which are aimed at turning that promise of improved productivity into a reality. An object oriented programming (OOP) approach has been adopted and a number of GUI components have been developed that run on several different operating systems. The emphasis is on assisting users in the setup and running of the optics programs without requiring any knowledge of the format, syntax, or similar requirements of the input. The components are being linked with several popular optics programs, including TRANSPORT, TURTLE, TRACE 3-D and PARMILA, to form integrated easy-to-use applications. Several advanced applications linking the GUI components with Lie algebra and other high-order simulation codes, as well as system level and facility modeling codes, are also under development. An overview of the work completed to date is presented, and examples of the new tools running on the Windows 95 operating system are illustrated.

  15. Essay: Bob Siemann-SLC Days at SLAC

    SciTech Connect

    Raubenheimer, Tor O.; /SLAC

    2011-11-14

    Bob Siemann was a great experimentalist and an excellent teacher.We will greatly miss him. Bob came to SLAC in early 1991 to work on the Stanford Linear Collider (SLC). The SLC was a challenging accelerator which began operating in the late 1980's but still had numerous obstacles to be overcome years into operation. One of the compounding difficulties was making reproducible measurements, since the stability of the collider was poor and the diagnostics were insufficient. Bob dove into this challenge and helped design experiments and diagnostics that provided further clarity. I first got to know Bob while I was still a graduate student, trying to finish my thesis and performing some experimental studies on the SLC, which, at the time, was proving to be very difficult. Most of my expertise had been in beam theory and simulation. Dealing with the real issues of the accelerator was challenging. Bob helped me understand the difference between systematic and statistical errors, and separate operational issues from the fundamental physics. His way of teaching was not to provide an explanation but to ask enough questions so that I could find the answer on my own - this was the best way to learn. I later asked Bob to be a reader on my thesis. As in all things, he took this role extremely seriously. He read through the draft and marked every page to the point where I was regretting my decision. However, his questions again helped me understand my own work better and greatly improved my thesis. Bob was also the de facto leader of an effort focused on the damping rings and the bunch compressors. He was great to work with. He made people think for themselves and refused to simply provide answers. He also worked hard himself, expressing real interest and curiosity. After the studies of the SLC damping rings identified a sawtooth instability due to the vacuum chamber impedance as a source of many downstream fluctuations, Bob took charge of upgrading the rings. As part of this

  16. 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.

  17. Cosmetic corrosion of painted aluminum and steel automotive body sheet: Results from outdoor and accelerated laboratory test methods

    SciTech Connect

    Moran, J.P.; Ziman, P.R.; Egbert, M.W.

    1995-11-01

    In recent years, increasing attention has been given to the need to develop an accelerated laboratory test method(s) for cosmetic corrosion of painted panels that realistically simulate in-service exposure. Much of that work has focused on steel substrates. The purpose of this research is to compare the corrosion performance of painted aluminum and steel sheet as determined om various laboratory methods and in-service exposure, and to develop a realistic accelerated test method for evaluation of the cosmetic corrosion of painted aluminum. Several aluminum sheet products from the 2xxx, 5xxx, and 6xxx alloy series have been tested. The steel substrates are similar to those used in other programs. The test methods chosen represent a cross-section of methods common to the automotive and aluminum industries for evaluation of painted sheet metal products. The results indicate that there is considerable difference in the relative correlation of various test methods to in-service exposure. In addition, there is considerable difference in the relative magnitudes and morphologies of corrosion, and occasionally in the relative rankings, as a function of test method. The influence of alloy composition and zinc phosphate coating weight are also discussed.

  18. Can Accelerators Accelerate Learning?

    NASA Astrophysics Data System (ADS)

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-01

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ) [1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  19. Final Design of the SLAC P2 Marx Klystron Modulator

    SciTech Connect

    Kemp, M.A.; Benwell, A.; Burkhart, C.; Larsen, R.; MacNair, D.; Nguyen, M.; Olsen, J.; /SLAC

    2011-11-08

    The SLAC P2 Marx has been under development for two years, and follows on the P1 Marx as an alternative to the baseline klystron modulator for the International Linear Collider. The P2 Marx utilizes a redundant architecture, air-insulation, a control system with abundant diagnostic access, and a novel nested droop correction scheme. This paper is an overview of the design of this modulator. There are several points of emphasis for the P2 Marx design. First, the modulator must be compatible with the ILC two-tunnel design. In this scheme, the modulator and klystron are located within a service tunnel with limited access and available footprint for a modulator. Access to the modulator is only practical from one side. Second, the modulator must have high availability. Robust components are not sufficient alone to achieve availability much higher than 99%. Therefore, redundant architectures are necessary. Third, the modulator must be relatively low cost. Because of the large number of stations in the ILC, the investment needed for the modulator components is significant. High-volume construction techniques which take advantage of an economy of scale must be utilized. Fourth, the modulator must be simple and efficient to maintain. If a modulator does become inoperable, the MTTR must be small. Fifth, even though the present application for the modulator is for the ILC, future accelerators can also take advantage of this development effort. The hardware, software, and concepts developed in this project should be designed such that further development time necessary for other applications is minimal.

  20. Laboratory simulation of ion acceleration in the presence of lower hybrid waves

    NASA Astrophysics Data System (ADS)

    McWilliams, R.; Koslover, R.; Boehmer, H.; Rynn, N.

    The UCI Q-machine has been used to simulate the effect of lower hybrid waves on ion acceleration. Laser induced fluorescence was used for high resolution, nonperturbing measurements of the ion velocity distribution function. The plasma consisted of a 1 m long, 5 cm diameter barium plasma of densities on the order of 10 to the 10th per cu cm contained by a 3 kG magnetic field. Substantial changes in the perpendicular ion distribution were found. Main-body ion heating occurred along with non-Maxwellian tail production.

  1. A 2 MeV, 100 mA electron accelerator for a small laboratory environment

    NASA Astrophysics Data System (ADS)

    Clayton, C. E.; Marsh, K. A.

    1993-03-01

    A small, high performance electron linear accelerator is described. It is a modified version of a commercially available portable x-ray source. The 9.3 GHz rf linac and beamline deliver a 3 ns train of approximately 15 ps pulses with a peak current, limited by beam loading of the rf structure, of more than 100 mA and a beam energy of around 2 MeV with a 5% full width at half maximum energy spread. The beam emittance is 6π mm mrad and the final spot size is 250 μm diam for f/10 focusing.

  2. Laboratory Experiments with the Concordia College High-Speed Dust Particle Accelerator

    NASA Astrophysics Data System (ADS)

    Manning, H. L.

    2011-12-01

    During the Apollo Era, NASA's Goddard Space Flight Center built a 2MeV high-speed, dust particle accelerator. This facility was used to test and calibrate the LEAM instrument which was flown to the lunar surface by Apollo 17. As the Apollo project wound down, NASA no longer had need of the dust particle accelerator, and in 1975, it was move to Concordia College in Moorhead, MN. Through the years, it has been maintained and some modifications and improvements have been made to it. In the past decade, the facility has been revived and used by several collaborating institutions to study dust detector instrumentation as well as the effects of dust impacts on various materials. We have tested a prototype, space-flight dust particle detector. Also, piezoelectric pins which can be used as dust detectors were studied to learn the pin's response to single particle impacts of different energies and momenta, and then those measured responses were compared with theoretical models. The effects of high speed impacts on ultra-high temperature ceramics, aerogel, and several different thin films have also been studied at our facility. The results of these experiments will be presented.

  3. Rapid estimation of lives of deficient superpave mixes and laboratory-based accelerated mix testing models

    NASA Astrophysics Data System (ADS)

    Manandhar, Chandra Bahadur

    The engineers from the Kansas Department of Transportation (KDOT) often have to decide whether or not to accept non-conforming Superpave mixtures during construction. The first part of this study focused on estimating lives of deficient Superpave pavements incorporating nonconforming Superpave mixtures. These criteria were based on the Hamburg Wheel-Tracking Device (HWTD) test results and analysis. The second part of this study focused on developing accelerated mix testing models to considerably reduce test duration. To accomplish the first objective, nine fine-graded Superpave mixes of 12.5-mm nominal maximum aggregate size (NMAS) with asphalt grade PG 64-22 from six administrative districts of KDOT were selected. Specimens were prepared at three different target air void levels Ndesign gyrations and four target simulated in-place density levels with the Superpave gyratory compactor. Average number of wheel passes to 20-mm rut depth, creep slope, stripping slope, and stripping inflection point in HWTD tests were recorded and then used in the statistical analysis. Results showed that, in general, higher simulated in-place density up to a certain limit of 91% to 93%, results in a higher number of wheel passes until 20-mm rut depth in HWTD tests. A Superpave mixture with very low air voids Ndesign (2%) level performed very poorly in the HWTD test. HWTD tests were also performed on six 12.5-mm NMAS mixtures with air voids Ndesign of 4% for six projects, simulated in-place density of 93%, two temperature levels and five load levels with binder grades of PG 64-22, PG 64-28, and PG 70-22. Field cores of 150-mm in diameter from three projects in three KDOT districts with 12.5-mm NMAS and asphalt grade of PG 64-22 were also obtained and tested in HWTD for model evaluation. HWTD test results indicated as expected. Statistical analysis was performed and accelerated mix testing models were developed to determine the effect of increased temperature and load on the duration of

  4. Future directions in controlling the LAMPF-PSR Accelerator Complex at Los Alamos National Laboratory

    SciTech Connect

    Stuewe, R.; Schaller, S.; Bjorklund, E.; Burns, M.; Callaway, T.; Carr, G.; Cohen, S.; Kubicek, D.; Harrington, M.; Poore, R.; Schultz, D.

    1991-01-01

    Four interrelated projects are underway whose purpose is to migrate the LAMPF-PSR Accelerator Complex control systems to a system with a common set of hardware and software components. Project goals address problems in performance, maintenance and growth potential. Front-end hardware, operator interface hardware and software, computer systems, network systems and data system software are being simultaneously upgraded as part of these efforts. The efforts are being coordinated to provide for a smooth and timely migration to a client-sever model-based data acquisition and control system. An increased use of the distributed intelligence at both the front-end and operator interface is a key element of the projects. 2 refs., 2 figs.

  5. Stunt Barbie - A Laboratory Practicum Combining Constant Velocity and Constant Acceleration

    NASA Astrophysics Data System (ADS)

    Hertting, Scott

    2011-04-01

    In preparing to teach the advanced physics course at my high school, I found it useful to work through the end-of-chapter problems in the book used by the advanced class. A problem on motion in one dimension involved a stunt woman in free fall from a tree limb onto a horse running beneath her.2 The problem presents a connected learning opportunity for students because it requires the use of the constant velocity model xf = v*t + xi and the constant acceleration model yf = ½* g* t2 + vyi* t + yi (where g = 9.8 m/s/s) to solve it. I named the stunt woman Barbie and created an activity titled "Stunt Barbie."

  6. Characteristics of a veteran acrylic lens relative to acrylic lens materials after accelerated laboratory weathering

    NASA Astrophysics Data System (ADS)

    Miller, David C.; Arndt, Thomas; Kogler, René

    2015-09-01

    The durability of poly(methyl methacrylate) is examined using veteran lenses obtained from CPV modules fielded for 27 years in Phoenix. The lens facets were milled from the lens interior, followed by depth-specific toming to characterize variation at four depths through the thickness. Optical transmittance was measured using a spectrophotometer, both with and without an integrating sphere. Diffuse transmittance (the optical haze) and yellowness index were determined from the transmittance. Molecular weight was characterized using size exclusion chromatography, also in conjunction with the toming. The veteran lens material is compared to contemporary PMMA formulations, aged in an indoor chamber. The modest reductions in transmittance and molecular weight for the lenses were generally similar to those of the contemporary materials, suggesting an indoor accelerated aging test might be used; additional tests must, however, be applied to invoke the haze, uniquely observed for the lens specimen.

  7. Radiation aspects of the B-Factory at SLAC

    SciTech Connect

    Liu, J.C.; Nelson, W.R.; Mao, X.S.

    1996-11-01

    The B-Factor is a high-energy physics project at SLAC that studies the phenomenon of CP violation from collisions between two stored beams; high energy electrons (HER, maximum 12-GeV) and low energy positrons (LER, maximum 4-GeV). Both the HER and LER are located in an underground tunnel of 2,200-m-long circumference with a maximum stored current of 3 A. The injector consists of the existing SLAC 2-mile-long LINAC with two extraction and transport lines for both rings. Radiation aspects of the machine are addressed in the context of machine protection and personnel protection. Specific illustrations (e.g., the estimations of neutron, photon and synchrotron radiation environment in the ring tunnel and the radiation levels outside a typical Interaction Region, etc.) are given to show a few natures of the radiation issues for the B-Factory and to reflect the appropriate SLAC policies on radiation safety.

  8. ACCELERATED SITE TECHNOLOGY DEPLOYMENT COST AND PERFORMANCE REPORT COMPARABILITY OF ISOCS INSTRUMENT IN RADIONUCLIDE CHARACTERICATION AT BROOKHAVEN NATIONAL LABORATORY

    SciTech Connect

    KALB,P.; LUCKETT,L.; MILLER,K.; GOGOLAK,C.; MILIAN,L.

    2001-03-01

    This report describes a DOE Accelerated Site Technology Deployment project being conducted at Brookhaven National Laboratory to deploy innovative, radiological, in situ analytical techniques. The technologies are being deployed in support of efforts to characterize the Brookhaven Graphite Research Reactor (BGRR) facility, which is currently undergoing decontamination and decommissioning. This report focuses on the deployment of the Canberra Industries In Situ Object Counting System (ISOCS) and assesses its data comparability to baseline methods of sampling and laboratory analysis. The battery-operated, field deployable gamma spectrometer provides traditional spectra of counts as a function of gamma energy. The spectra are then converted to radionuclide concentration by applying innovative efficiency calculations using monte carlo statistical methods and pre-defined geometry templates in the analysis software. Measurement of gamma emitting radionuclides has been accomplished during characterization of several BGRR components including the Pile Fan Sump, Above Ground Ducts, contaminated cooling fans, and graphite pile internals. Cs-137 is the predominant gamma-emitting radionuclide identified, with smaller quantities of Co-60 and Am-241 detected. The Project used the Multi-Agency Radiation Survey and Site Investigation Manual guidance and the Data Quality Objectives process to provide direction for survey planning and data quality assessment. Analytical results have been used to calculate data quality indicators (DQI) for the ISOCS measurements. Among the DQIs assessed in the report are sensitivity, accuracy, precision, bias, and minimum detectable concentration. The assessment of the in situ data quality using the DQIs demonstrates that the ISOCS data quality can be comparable to definitive level laboratory analysis when the field instrument is supported by an appropriate Quality Assurance Project Plan. A discussion of the results obtained by ISOCS analysis of

  9. Prediction and accelerated laboratory discovery of previously unknown 18-electron ABX compounds

    NASA Astrophysics Data System (ADS)

    Gautier, Romain; Zhang, Xiuwen; Hu, Linhua; Yu, Liping; Lin, Yuyuan; Sunde, Tor O. L.; Chon, Danbee; Poeppelmeier, Kenneth R.; Zunger, Alex

    2015-04-01

    Chemists and material scientists have often focused on the properties of previously reported compounds, but neglect numerous unreported but chemically plausible compounds that could have interesting properties. For example, the 18-valence electron ABX family of compounds features examples of topological insulators, thermoelectrics and piezoelectrics, but only 83 out of 483 of these possible compounds have been made. Using first-principles thermodynamics we examined the theoretical stability of the 400 unreported members and predict that 54 should be stable. Of those previously unreported ‘missing’ materials now predicted to be stable, 15 were grown in this study; X-ray studies agreed with the predicted crystal structure in all 15 cases. Among the predicted and characterized properties of the missing compounds are potential transparent conductors, thermoelectric materials and topological semimetals. This integrated process—prediction of functionality in unreported compounds followed by laboratory synthesis and characterization—could be a route to the systematic discovery of hitherto missing, realizable functional materials.

  10. PEP 2: SLAC-based Asymmetric B Factory

    SciTech Connect

    Fieguth, T.

    1992-09-01

    The proposal for upgrading the existing PEP collider at SLAC to enable the copious production of boosted B mesons is the result of several years of collaborative study by groups representing LBL, LLNL and SLAC. The PEP II design has evolved in a considered fashion from its initial conceptualization to a very advanced level of understanding, well-substantiated by R&D results on the key design issues. We describe the proposed upgrade, review the early conceptual decisions, outline the significant remaining questions, and briefly describe current results from the ongoing R&D effort which have shown these questions to be tractable and the initial concepts to be sound.

  11. PEP 2: SLAC-based Asymmetric B Factory

    SciTech Connect

    Fieguth, T.

    1992-09-01

    The proposal for upgrading the existing PEP collider at SLAC to enable the copious production of boosted B mesons is the result of several years of collaborative study by groups representing LBL, LLNL and SLAC. The PEP II design has evolved in a considered fashion from its initial conceptualization to a very advanced level of understanding, well-substantiated by R D results on the key design issues. We describe the proposed upgrade, review the early conceptual decisions, outline the significant remaining questions, and briefly describe current results from the ongoing R D effort which have shown these questions to be tractable and the initial concepts to be sound.

  12. Cracking and delamination behaviors of photovoltaic backsheet after accelerated laboratory weathering

    NASA Astrophysics Data System (ADS)

    Lin, Chiao-Chi; Lyu, Yadong; Hunston, Donald L.; Kim, Jae Hyun; Wan, Kai-Tak; Stanley, Deborah L.; Gu, Xiaohong

    2015-09-01

    The channel crack and delamination phenomena that occurred during tensile tests were utilized to study surface cracking and delamination properties of a multilayered backsheet. A model sample of commercial PPE (polyethylene terephthalate (PET)/PET/ethylene vinyl acetate (EVA)) backsheet was studied. Fragmentation testing was performed after accelerated aging with and without ultraviolet (UV) irradiation in two relative humidity (RH) levels (5 % RH and 60 % RH) at elevated temperature (85 °C) conditions for 11 days and 22 days. Results suggest that the embrittled surface layer resulting from the UV photo-degradation is responsible for surface cracking when the strain applied on the sample is far below the yielding strain (2.2 %) of the PPE sample. There was no surface cracking observed on the un-aged sample and samples aged without UV irradiation. According to the fragmentation testing results, the calculated fracture toughness (KIC) values of the embrittled surface layer are as low as 0.027 MPa·m1/2 to 0.104 MPa·m1/2, depending on the humidity levels and aging times. Surface analysis using attenuated total reflectance Fourier transform infrared and atomic force microscopy shows the degradation mechanism of the embrittled surface layer is a combination of the photodegradation within a certain degradation depth and the moisture erosion effect depending on the moisture levels. Specifically, UV irradiation provides a chemical degradation effect while moisture plays a synergistic effect on surface erosion, which influences surface roughness after aging. Finally, there was no delamination observed during tensile testing in this study, suggesting the surface cracking problem is more significant than the delamination for the PPE backsheet material and conditions tested here.

  13. The André E. Lalonde AMS Laboratory - The new accelerator mass spectrometry facility at the University of Ottawa

    NASA Astrophysics Data System (ADS)

    Kieser, W. E.; Zhao, X.-L.; Clark, I. D.; Cornett, R. J.; Litherland, A. E.; Klein, M.; Mous, D. J. W.; Alary, J.-F.

    2015-10-01

    The University of Ottawa, Canada, has installed a multi-element, 3 MV tandem AMS system as the cornerstone of their new Advanced Research Complex and the principal analytical instrument of the André E. Lalonde Accelerator Mass Spectrometry Laboratory. Manufactured by High Voltage Engineering Europa B.V., the Netherlands, it is equipped with a 200 sample ion source, a high resolution, 120° injection magnet, a 90° high energy analysis magnet (mass-energy product 350 MeV-AMU), a 65°, 1.7 m radius electric analyzer and a 2 channel gas ionization detector. It is designed to analyze isotopes ranging from tritium to the actinides and to accommodate the use of fluoride target materials. This system is being extended with a second injection line, consisting of selected components from the IsoTrace Laboratory, University of Toronto. This line will contain a pre-commercial version of the Isobar Separator for Anions, manufactured by Isobarex Corp., Bolton, Ontario, Canada. This instrument uses selective ion-gas reactions in a radio-frequency quadrupole cell to attenuate both atomic and molecular isobars. This paper discusses the specifications of the new AMS equipment, reports on the acceptance test results for 10Be, 14C, 26Al and 127I and presents typical spectra for 10Be and actinide analyses.

  14. Coupled Mechanical-Electrochemical-Thermal Modeling for Accelerated Design of EV Batteries; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Pesaran, Ahmad; Zhang, Chao; Kim, Gi-heon; Santhanagopalan, Shriram

    2015-06-10

    The physical and chemical phenomena occurring in a battery are many and complex and in many different scales. Without a better knowledge of the interplay among the multi-physics occurring across the varied scales, it is very challenging and time consuming to design long-lasting, high-performing, safe, affordable large battery systems, enabling electrification of the vehicles and modernization of the grid. The National Renewable Energy Laboratory, a U.S. Department of Energy laboratory, has been developing thermal and electrochemical models for cells and battery packs. Working with software producers, carmakers, and battery developers, computer-aided engineering tools have been developed that can accelerate the electrochemical and thermal design of batteries, reducing time to develop and optimize them and thus reducing the cost of the system. In the past couple of years, we initiated a project to model the mechanical response of batteries to stress, strain, fracture, deformation, puncture, and crush and then link them to electrochemical and thermal models to predict the response of a battery. This modeling is particularly important for understanding the physics and processes that happen in a battery during a crush-inducing vehicle crash. In this paper, we provide an overview of electrochemical-thermal-mechanical models for battery system understanding and designing.

  15. Accelerator development for the NRL (Naval Research Laboratory) free-electron-laser program. Final report, July 1981-April 1986

    SciTech Connect

    Lucey, R.; Putnam, S.

    1988-06-01

    Included in the report are descriptions of the final assembly and operation of the Linear Induction Accelerator(LIA), installation and testing of a new accelerating gap in the five-core stage of the accelerator to operate at 150 kV, and the moving of and modifications of the charging and firing controls for remote operation of the accelerator.

  16. Production of high intensity electron bunches for the SLAC Linear Collider

    SciTech Connect

    James, M.B.

    1987-08-01

    This thesis describes the design and performance of a high intensity electron injecfor for the SLAC Linear Collider. Motivation for the collider and the specifications for the injector are discussed. An analytic theory of the bunching and capture of electrons by rf fields is discussed in the limit of low space charge and small signal. The design and performance of SLAC's main injector are described to illustrate a successful application of this theory. The bunching and capture of electrons by rf fields are then discussed in the limit of high space charge and large signal, and a description of the design of the collider injector follows. In the limit of high space charge forces and large rf signals, the beam dynamics are considerably more complex and numerical simulations are required to predict particle motion. A computer code which models the longitudinal dynamics of electrons in the presence of space charge and rf fields is described. The results of the simulations, the resulting collider injector design and the various components which make up the collider injector are described. These include the gun, subharmonic bunchers, traveling-wave buncher and velocity-of-light accelerator section. Finally, the performance of the injector is described including the beam intensity, bunch length, transverse emittance and energy spectrum. While the final operating conditions differ somewaht from the design, the performance of the collider injector is in good agreement with the numerical simulations and meets all of the collider specifications. 28 refs.

  17. SLAC modulator system improvements and reliability results

    SciTech Connect

    Donaldson, A.R.

    1998-06-01

    In 1995, an improvement project was completed on the 244 klystron modulators in the linear accelerator. The modulator system has been previously described. This article offers project details and their resulting effect on modulator and component reliability. Prior to the project, the authors had collected four operating cycles (1991 through 1995) of MTTF data. In this discussion, the '91 data will be excluded since the modulators operated at 60 Hz. The five periods following the '91 run were reviewed due to the common repetition rate at 120 Hz.

  18. SLAC linear collider conceptual design report

    SciTech Connect

    Not Available

    1980-06-01

    The linear collider system is described in detail, including the transport system, the collider lattice, final focusing system, positron production, beam damping and compression, high current electron source, instrumentation and control, and the beam luminosity. The experimental facilities and the experimental uses are discussed along with the construction schedule and estimated costs. Appendices include a discussion of space charge effects in the linear accelerator, emittance growth in the collider, the final focus system, beam-beam instabilities and pinch effects, and detector backgrounds. (GHT)

  19. Electron transport of a Linac Coherent Light Source (LCLS) using the SLAC linac

    SciTech Connect

    Bane, K.L.; Raubenheimer, T.O.; Seeman, J.T.

    1993-05-01

    A linac configuration providing a low emittance high peak current electron beam is under study for a potential Linac Coherent Light Source (LCLS) based on the SLAC accelerator. The parameters of the final electron bunch are nearing the technological limits of present accelerators in both transverse and longitudinal phase space. In this note we describe a layout of the RF gun, linac, and bunch compressors to deliver the required bunch properties. We consider a bunch that is generated by an rf gun and accelerated to 7 GeV in 900 m of SLAC linac structure before it enters the wiggler. We assume that the rf gun generates a gaussian beam with an energy of 10 MeV, a population N = 6 {times} 10{sup 9}e{sup {minus}}, an rms length {sigma}{sub z} = 0.5 mm, an rms energy spread {sigma}{sub {delta}} = 0.2%, and normalized rms emittances {gamma}{epsilon}{sub x,y} = 3 mm-mrad. At the end of the linac, we require that the peak current {cflx I} {approx_gt} 2.5 kA and the peak-to-peak energy spread {Delta}{delta} {approx_lt} 0.2%. To obtain the required high peak current, we need to compress the bunch length by a factor greater than 10. In deciding at what position in the linac to compress we need to consider three issues: the longitudinal wakefield in the linac, this increases the beam`s energy spread and is harder to compensate with short bunches, the transverse wakefield and rf deflections in the linac, these increase the transverse emittance of the beam and are more severe for long bunches, and the effects of phase and current jitter which will change the bunch length and therefore the peak current of the beam. In this paper, we will describe how we compress the bunch to meet these three criteria. Then, we will briefly describe the bunch compressor optics and finally we will mention some details specific to the SLAC site.

  20. SLAC Users Bulletin No. 102, November 1985-April 1986

    SciTech Connect

    Keller, L. P.; Edminster, D.

    1986-01-01

    The status experimental activities at SLAC is reported, including the long-range schedule and a list of approved high-energy experiments. Work on PEP, SPEAR, and the SLC is included, as well as computing. Such operational data as operating hours and experimental hours are given. (LEW)

  1. SLAC: A Tool for Addressing Chaos in the Ecology Classroom

    ERIC Educational Resources Information Center

    Hamilton, A. J.

    2005-01-01

    Until the early 1970s, ecologists generally assumed that erratic fluctuations observed in natural populations were a product of stochastic noise. It is now known that extremely complex dynamics can arise from basic deterministic processes. This field of study is generally called chaos theory. Here, a computer program, SLAC (Stability, Limits, And…

  2. Recent Advances in Plasma Acceleration

    SciTech Connect

    Hogan, Mark

    2007-03-19

    The costs and the time scales of colliders intended to reach the energy frontier are such that it is important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators a drive beam, either laser or particle, produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultra-high accelerating fields over a substantial length to achieve a significant energy gain. More than 42 GeV energy gain was achieved in an 85 cm long plasma wakefield accelerator driven by a 42 GeV electron drive beam in the Final Focus Test Beam (FFTB) Facility at SLAC. Most of the beam electrons lose energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of {approx}52 GV/m. This effectively doubles their energy, producing the energy gain of the 3 km long SLAC accelerator in less than a meter for a small fraction of the electrons in the injected bunch. Prospects for a drive-witness bunch configuration and high-gradient positron acceleration experiments planned for the SABER facility will be discussed.

  3. The Turn-on of LCLS: the X-Ray Free Electron Laser at SLAC ( Keynote - 2011 JGI User Meeting)

    ScienceCinema

    Drell, Persis [SLAC Director

    2011-06-08

    The U.S. Department of Energy Joint Genome Institute (JGI) invited scientists interested in the application of genomics to bioenergy and environmental issues, as well as all current and prospective users and collaborators, to attend the annual DOE JGI Genomics of Energy & Environment Meeting held March 22-24, 2011 in Walnut Creek, Calif. The emphasis of this meeting was on the genomics of renewable energy strategies, carbon cycling, environmental gene discovery, and engineering of fuel-producing organisms. The meeting features presentations by leading scientists advancing these topics. SLAC National Laboratory Director Persis Drell gives a keynote talk on "The Turn-on of LCLS: the X-Ray Free-Electron Laser at SLAC" at the 6th Genomics of Energy & Environment Meeting on March 22, 2011

  4. The Turn-on of LCLS: the X-Ray Free Electron Laser at SLAC ( Keynote - 2011 JGI User Meeting)

    SciTech Connect

    Drell, Persis

    2011-03-22

    The U.S. Department of Energy Joint Genome Institute (JGI) invited scientists interested in the application of genomics to bioenergy and environmental issues, as well as all current and prospective users and collaborators, to attend the annual DOE JGI Genomics of Energy & Environment Meeting held March 22-24, 2011 in Walnut Creek, Calif. The emphasis of this meeting was on the genomics of renewable energy strategies, carbon cycling, environmental gene discovery, and engineering of fuel-producing organisms. The meeting features presentations by leading scientists advancing these topics. SLAC National Laboratory Director Persis Drell gives a keynote talk on "The Turn-on of LCLS: the X-Ray Free-Electron Laser at SLAC" at the 6th Genomics of Energy & Environment Meeting on March 22, 2011

  5. Representing Value as Digital Object: A Discussion of Transferability and Anonymity; Digital Library Initiatives of the Deutsche Forschungsgemeinschaft; CrossRef Turns One; Fermi National Accelerator Laboratory (Fermilab).

    ERIC Educational Resources Information Center

    Kahn, Robert E.; Lyons, Patrice A.; Brahms, Ewald; Brand, Amy; van den Bergen, Mieke

    2001-01-01

    Includes four articles that discuss the use of digital objects to represent value in a network environment; digital library initiatives at the central public funding organization for academic research in Germany; an application of the Digital Object Identifier System; and the Web site of the Fermi National Accelerator Laboratory. (LRW)

  6. Transverse wakefield control and feedback in the SLC (SLAC Linear Collider) linear

    SciTech Connect

    Seeman, J.T.; Campisi, I.E.; Herrmannsfeldt, W.; Lee, M.; Petersen, A.; Phinney, N.; Ross, M.; Abrams, G.S.; Adolphsen, C.; Soderstrom, E.

    1987-01-01

    Transverse wakefields in the linac of the SLAC Linear Collider (SLC) have been observed to enlarge the effective emittance of beams which are not properly centered in the accelerating structure. A fast feedback system has been constructed to minimize the enlargement under changing conditions by controlling the beam launching parameters. Theoretical aspects of this transverse feedback system are reviewed as well as the design of the beam sensors, launch controllers, communication equipment and data processing micro-computer. A variety of beam observations have been made. They show that dispersion as well as wakefield effects are important. In the near future the fast transverse feedback system will be beam tested, and algorithms tailored to the noise environment of the SLC will be tried.

  7. Optics Design for a Soft X-ray FEL at the SLAC A-Line

    SciTech Connect

    Geng, H; Ding, Y.; Emma, P.; Huang, Z.; Nosochkov, Y.; Woodley, M.; /SLAC

    2009-05-15

    LCLS capabilities can be significantly extended with a second undulator aiming at the soft x-ray spectrum (1-5 nm). To allow for simultaneous hard and soft x-ray operations, 14 GeV beams at the end of the LCLS accelerator can be intermittently switched into the SLAC A-line (the beam transport line to End Station A) where the second undulator may be located. In this paper, we discuss the A-line optics design for transporting the high-brightness LCLS beams using the existing tunnel. To preserve the high brightness of the LCLS beams, special attention is paid to effects of incoherent and coherent synchrotron radiation. Start-to-end simulations using realistic LCLS beam distributions are carried out.

  8. Results of the SLAC LCLS Gun High-Power RF Tests

    SciTech Connect

    Dowell, D.H.; Jongewaard, E.; Limborg-Deprey, C.; Schmerge, J.F.; Li, Z.; Xiao, L.; Wang, J.; Lewandowski, J.; Vlieks, A.; /SLAC

    2007-11-02

    The beam quality and operational requirements for the Linac Coherent Light Source (LCLS) currently being constructed at SLAC are exceptional, requiring the design of a new RF photocathode gun for the electron source. Based on operational experience at SLAC's GTF and SDL and ATF at BNL as well as other laboratories, the 1.6cell s-band (2856MHz) gun was chosen to be the best electron source for the LCLS, however a significant redesign was necessary to achieve the challenging parameters. Detailed 3-D analysis and design was used to produce near-perfect rotationally symmetric rf fields to achieve the emittance requirement. In addition, the thermo-mechanical design allows the gun to operate at 120Hz and a 140MV/m cathode field, or to an average power dissipation of 4kW. Both average and pulsed heating issues are addressed in the LCLS gun design. The first LCLS gun is now fabricated and has been operated with high-power RF. The results of these high-power tests are presented and discussed.

  9. Do you want to build such a machine? : Designing a high energy proton accelerator for Argonne National Laboratory.

    SciTech Connect

    Paris, E.

    2004-04-05

    Argonne National Laboratory's efforts toward researching, proposing and then building a high-energy proton accelerator have been discussed in a handful of studies. In the main, these have concentrated on the intense maneuvering amongst politicians, universities, government agencies, outside corporations, and laboratory officials to obtain (or block) approval and/or funds or to establish who would have control over budgets and research programs. These ''top-down'' studies are very important but they can also serve to divorce such proceedings from the individuals actually involved in the ground-level research which physically served to create theories, designs, machines, and experiments. This can lead to a skewed picture, on the one hand, of a lack of effect that so-called scientific and technological factors exert and, on the other hand, of the apparent separation of the so-called social or political from the concrete practice of doing physics. An exception to this approach can be found in the proceedings of a conference on ''History of the ZGS'' held at Argonne at the time of the Zero Gradient Synchrotron's decommissioning in 1979. These accounts insert the individuals quite literally as they are, for the most part, personal reminiscences of those who took part in these efforts on the ground level. As such, they are invaluable raw material for historical inquiry but generally lack the rigor and perspective expected in a finished historical work. The session on ''Constructing Cold War Physics'' at the 2002 annual History of Science Society Meeting served to highlight new approaches circulating towards history of science and technology in the post-WWII period, especially in the 1950s. There is new attention towards the effects of training large numbers of scientists and engineers as well as the caution not to equate ''national security'' with military preparedness, but rather more broadly--at certain points--with the explicit ''struggle for the hearts and minds of

  10. Organizational cultural survey of the Stanford Linear Accelerator Center

    SciTech Connect

    Not Available

    1991-11-01

    At the request of the Department of Energy, an Organizational Survey (OS) was administered at the Stanford Accelerator Center (SLAC). The OS measured employees' opinions on subjects such as organizational culture, communication, commitment, group cohesion, coordination, safety, environmental issues, and job satisfaction. The result of this work was a quantitative measure of the notion of culture at the SLAC site. This report presents these results and discusses their interpretation.

  11. An organizational survey of the Stanford Linear Accelerator Center

    SciTech Connect

    Shurberg, D.A.; Haber, S.B.

    1991-11-01

    At the request of the Department of Energy, an Organizational Survey (OS) was administered at the Stanford Accelerator Center (SLAC). The OS measured employees` opinions on subjects such as organizational culture, communication, commitment, group cohesion, coordination, safety, environmental issues, and job satisfaction. The result of this work was a quantitative measure of the notion of culture at the SLAC site. This report presents these results and discusses their interpretation.

  12. Organizational cultural survey of the Stanford Linear Accelerator Center

    SciTech Connect

    Not Available

    1991-11-01

    At the request of the Department of Energy, an Organizational Survey (OS) was administered at the Stanford Linear Accelerator Center (SLAC). The OS measured employees' opinions on subjects such as organizational culture, communication, commitment, group cohesion, coordination, safety, environmental issues, and job satisfaction. The result of this work was a quantitative measure of the notion of culture at the SLAC site. This report presents these results and discusses their interpretation.

  13. An organizational survey of the Stanford Linear Accelerator Center

    SciTech Connect

    Shurberg, D.A.; Haber, S.B.

    1991-11-01

    At the request of the Department of Energy, an Organizational Survey (OS) was administered at the Stanford Accelerator Center (SLAC). The OS measured employees' opinions on subjects such as organizational culture, communication, commitment, group cohesion, coordination, safety, environmental issues, and job satisfaction. The result of this work was a quantitative measure of the notion of culture at the SLAC site. This report presents these results and discusses their interpretation.

  14. Scaphoidectomy and Capsulodesis for SNAC or SLAC Stage II

    PubMed Central

    Trumble, Thomas E.; Rafijah, Gregory; Alexander, Hayley; Waitayawinyu, Thanapong

    2012-01-01

    Two common types of wrist arthritis are scapholunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC). In stage II SLAC or SNAC, there is arthritis between the scaphoid and the radius, sparing the cartilage between the capitate and the lunate and between the lunate and the radius. When nonsurgical treatment failed, scaphoidectomy plus capsulorrhaphy was used in 8 patients to provide pain relief without requiring an arthrodesis or compromising the radiolunate articulation. After surgery the pain scores improved from 8.5 preoperatively to 2.4 postoperatively. The Disabilities of the Arm, Shoulder, and Hand (DASH) score averaged 21, and the grip strength improved from 18 to 28 kg (81% of the contralateral side). PMID:24179716

  15. Compliance of SLAC_s Laser Safety Program with OSHA Requirements for the Control of Hazardous Energy

    SciTech Connect

    Woods, Michael; /SLAC

    2009-01-15

    SLAC's COHE program requires compliance with OSHA Regulation 29CFR1910.147, 'The control of hazardous energy (lockout/tagout)'. This regulation specifies lockout/tagout requirements during service and maintenance of equipment in which the unexpected energization or start up of the equipment, or release of stored energy, could cause injury to workers. Class 3B and Class 4 laser radiation must be considered as hazardous energy (as well as electrical energy in associated equipment, and other non-beam energy hazards) in laser facilities, and therefore requires careful COHE consideration. This paper describes how COHE is achieved at SLAC to protect workers against unexpected Class 3B or Class 4 laser radiation, independent of whether the mode of operation is normal, service, or maintenance.

  16. Arthroscopic Resection Arthroplasty of the Radial Column for SLAC Wrist

    PubMed Central

    Cobb, Tyson K.; Walden, Anna L.; Wilt, Jessica M.

    2014-01-01

    Background Symptomatic advanced scapholunate advanced collapse (SLAC) wrists are typically treated with extensive open procedures, including but not limited to scaphoidectomy plus four-corner fusion (4CF) and proximal row carpectomy (PRC). Although a minimally invasive arthroscopic option would be desirable, no convincing reports exist in the literature. The purpose of this paper is to describe a new surgical technique and outcomes on 14 patients who underwent arthroscopic resection arthroplasty of the radial column (ARARC) for arthroscopic stage II through stage IIIB SLAC wrists and to describe an arthroscopic staging classification of the radiocarpal joint for patients with SLAC wrist. Patients and Methods Data were collected prospectively on 17 patients presenting with radiographic stage I through III SLAC wrist who underwent ARARC in lieu of scaphoidectomy and 4CF or PRC. Fourteen patients (12 men and 2 women) subject to 1-year follow-up were included. The average age was 57 years (range 41 to 78). The mean follow-up was 24 months (range 12 to 61). Arthroscopic resection arthroplasty of the radial column is described for varying stages of arthritic changes of the radioscaphoid joint. Midcarpal resection was not performed. Results The mean Disabilities of the Arm, Shoulder, and Hand (DASH) score was 66 preoperatively and 28 at final follow-up. The mean satisfaction (0 = not satisfied, 5 = completely satisfied) at final follow-up was 4.5 (range 3 to 5). The pain level (on 0–10 scale) improved from 6.6 to 1.3. The total arc of motion changed from 124° preoperatively to 142° postoperatively following an ARARC. Grip was 16 kg preoperatively and 18 kg postoperatively. Radiographic stages typically underestimated arthroscopic staging. Although four of our patients appeared to be radiographic stage I, all were found to have arthritis involving some or all of the radioscaphoid articulation at the time of arthroscopy. Clinical Relevance

  17. High Power Beam Test and Measurement of Emittance Evolution of a 1.6-Cell Photocathode RF Gun at Pohang Accelerator Laboratory

    NASA Astrophysics Data System (ADS)

    Park, Jang-Ho; Park, Sung-Ju; Kim, Changbum; Parc, Yong-Woon; Hong, Ju-Ho; Huang, Jung-Yun; Xiang, Dao; Wang, Xijie; Ko, In Soo

    2007-04-01

    A Brookhaven National Laboratory (BNL) GUN-IV type photocathode rf gun has been fabricated to use in femtosecond electron diffraction (FED), femtosecond far infrared radiation (fs-FIR) facility, and X-ray free electron laser (XFEL) facilities at the Pohang Accelerator Laboratory (PAL). The gun consists of a 1.6-cell cavity with a copper cathode, a solenoid magnet, beam diagnostic components and auxiliary systems. We report here the measurement of the basic beam parameters which confirm a successful fabrication of the photocathode RF gun system. The emittance evolution is measured by an emittance meter and compared with the PARMELA simulation, which shows a good agreement.

  18. Progress on plasma accelerators

    SciTech Connect

    Chen, P.

    1986-05-01

    Several plasma accelerator concepts are reviewed, with emphasis on the Plasma Beat Wave Accelerator (PBWA) and the Plasma Wake Field Accelerator (PWFA). Various accelerator physics issues regarding these schemes are discussed, and numerical examples on laboratory scale experiments are given. The efficiency of plasma accelerators is then revealed with suggestions on improvements. Sources that cause emittance growth are discussed briefly.

  19. SuperB Progress Report for Accelerator

    SciTech Connect

    Biagini, M.E.; Boni, R.; Boscolo, M.; Buonomo, B.; Demma, T.; Drago, A.; Esposito, M.; Guiducci, S.; Mazzitelli, G.; Pellegrino, L.; Preger, M.A.; Raimondi, P.; Ricci, R.; Rotundo, U.; Sanelli, C.; Serio, M.; Stella, A.; Tomassini, S.; Zobov, M.; Bertsche, K.; Brachman, A.; /SLAC /Novosibirsk, IYF /INFN, Pisa /Pisa U. /Orsay, LAL /Annecy, LAPP /LPSC, Grenoble /IRFU, SPP, Saclay /DESY /Cockroft Inst. Accel. Sci. Tech. /U. Liverpool /CERN

    2012-02-14

    This report details the progress made in by the SuperB Project in the area of the Collider since the publication of the SuperB Conceptual Design Report in 2007 and the Proceedings of SuperB Workshop VI in Valencia in 2008. With this document we propose a new electron positron colliding beam accelerator to be built in Italy to study flavor physics in the B-meson system at an energy of 10 GeV in the center-of-mass. This facility is called a high luminosity B-factory with a project name 'SuperB'. This project builds on a long history of successful e+e- colliders built around the world, as illustrated in Figure 1.1. The key advances in the design of this accelerator come from recent successes at the DAFNE collider at INFN in Frascati, Italy, at PEP-II at SLAC in California, USA, and at KEKB at KEK in Tsukuba Japan, and from new concepts in beam manipulation at the interaction region (IP) called 'crab waist'. This new collider comprises of two colliding beam rings, one at 4.2 GeV and one at 6.7 GeV, a common interaction region, a new injection system at full beam energies, and one of the two beams longitudinally polarized at the IP. Most of the new accelerator techniques needed for this collider have been achieved at other recently completed accelerators including the new PETRA-3 light source at DESY in Hamburg (Germany) and the upgraded DAFNE collider at the INFN laboratory at Frascati (Italy), or during design studies of CLIC or the International Linear Collider (ILC). The project is to be designed and constructed by a worldwide collaboration of accelerator and engineering staff along with ties to industry. To save significant construction costs, many components from the PEP-II collider at SLAC will be recycled and used in this new accelerator. The interaction region will be designed in collaboration with the particle physics detector to guarantee successful mutual use. The accelerator collaboration will consist of several groups at present universities and national

  20. A Proof-Of-Principle Echo-Enabled Harmonic Generation Experiment at SLAC

    SciTech Connect

    Dunning, Michael; Colby, Eric; Ding, Yuantao; Frederico, Joel; Gilevich, Sasha; Hast, Carsten; Jobe, R.; McCormick, Douglas; Nelson, Janice; Raubenheimer, Tor; Soong, Ken; Stupakov, Gennady; Szalata, Zenon; Walz, Dieter; Weathersby, Stephen; Woodley, Mark; Xiang, Dao; Corlett, John; Penn, Gregory; Prestemon, Soren; Qiang, Ji; /LBL, Berkeley /LBL, Berkeley /LBL, Berkeley /LBL, Berkeley /LPHE, Lausanne

    2011-05-20

    In this paper we describe the technical design of an ongoing proof-of-principle echo-enabled harmonic generation (EEHG) experiment at the Next Linear Collider Test Accelerator (NLCTA) at SLAC.We present the design considerations and the technical details of the experiment. Recently a new method, entitled echo-enabled harmonic generation, was proposed for generation of high harmonics using the beam echo effect. In an EEHG free electron laser (FEL), an electron beam is energy modulated in a modulator and then sent through a dispersive section with a high dispersion strength. After this first stage, the modulation obtained in the modulator is macroscopically washed out, while simultaneously introducing complicated fine structure (separated energy bands) into the phase space of the beam. A second laser is used to further modulate the beam energy in a second modulator. After passing through a second dispersive section, the separated energy bands will be converted into current modulation and the echo signal then occurs as a recoherence effect caused by the mixing of the correlations between the modulation in the second modulator and the fine structures in the beam. The EEHG scheme has a remarkable up-frequency conversion efficiency; it has been shown that the EEHG FEL scheme may allow generation of soft x-rays directly from a UV seed laser in a single stage. In order to confirm the physics behind the EEHG technique and benchmark the theory, a proof-of-principleEEHG experimentwas planned at SLAC. The experiment is now in a commissioning stage and the preliminary results are reported in a separate paper of these proceedings. In this paper we present the design considerations and the details of the experiment setup.

  1. Experiments with very-high-power RF pulses at SLAC

    SciTech Connect

    Hogg, H.A.; Loew, G.A.; Price, V.G.

    1983-03-01

    Experiments in which the powers of two SLAC klystrons were combined and fed into a resonant cavity pulse-compression system (SLED) are described. Pulse powers up to 65 MW into SLED were reached. The corresponding instantaneous peak power out of SLED was 390 MW. After normal initial aging, no persistent RF breakdown problems were encountered. X-radiation at the SLED cavities was generally less than 400 mR/h after aging. The theoretical relationship between x-radiation intensity and RF electric field strength is discussed.

  2. Superconducting final focus for the SLAC Linear Collider

    SciTech Connect

    Ash, W.W.; Barrera, F.; Burgess, W.; Cook, K.; Cutler, H.; Ferrie, J.; Petersen, H.; Sawyer, D.; Rinta, R.

    1992-05-01

    Triplets composed of superconducting quadrupoles have been built and installed as the final focusing element for the high-energy positron and electron beams of the SLAC Linear Collider. Special features include independent alignment to 100-micron tolerance inside a common cryostat; non-magnetic materials to allow operation inside the detector`s solenoid field; a continuous-flow helium-only system using 50-meter-long flexible transfer lines; and complete operation of the system before installation. The mechanical design and cryogenic operation experience are presented.

  3. Superconducting final focus for the SLAC Linear Collider

    SciTech Connect

    Ash, W.W.; Barrera, F.; Burgess, W.; Cook, K.; Cutler, H.; Ferrie, J.; Petersen, H.; Sawyer, D.; Rinta, R.

    1992-05-01

    Triplets composed of superconducting quadrupoles have been built and installed as the final focusing element for the high-energy positron and electron beams of the SLAC Linear Collider. Special features include independent alignment to 100-micron tolerance inside a common cryostat; non-magnetic materials to allow operation inside the detector's solenoid field; a continuous-flow helium-only system using 50-meter-long flexible transfer lines; and complete operation of the system before installation. The mechanical design and cryogenic operation experience are presented.

  4. Laser Development for Future Photocathode Research at SLAC

    NASA Astrophysics Data System (ADS)

    Brachmann, A.; Cone, K.; Clendenin, J. E.; Garwin, E. L.; Kirby, R. E.; Luh, D.; Maruyama, T.; Prepost, R.; Prescott, C. Y.

    2005-08-01

    This report summarizes results of recent upgrades to SLAC's polarized source drive laser system. A Q-switching system has been incorporated into the flashlamp-pumped Ti:Sapphire laser system. The Q-switched laser provides energies up to 5 mJ for a 200 ns long pulse. Slow Q-switching provides control over length and shape of the laser pulse. A peak current of > 5.5 A has been demonstrated using a GaAs photocathode illuminated by this laser system.

  5. Using the SLAC VHF and UHF radio systems

    SciTech Connect

    Struven, W.

    1987-02-01

    The use of the SLAC VHF and UHF Radio Systems and the Tunnel Antenna Systems as they are presently configured is described. The original radio system was built in 1966 and has grown in scope over the years. The Tunnel Antenna Systems were developed for, and first installed in, the PEP ring, and later added to other tunnels and redesigned to cover the UHF range, as well as VHF. The UHF radio system was designed and built for SLC use, and was first used in the SLC Arcs. The three radio systems will be described and the capabilities of each system will be defined.

  6. Dielectric Wakefield Accelerating Structure as a Source of Terahertz Coherent Cerenkov Radiation

    SciTech Connect

    Cook, A. M.; Rosenzweig, J. B.; Badakov, H.; Travish, G.; Tikhoplav, R.; Williams, O. B.; England, R. J.; Thompson, M. C.

    2006-11-27

    We discuss future experimental work proposed to study the performance of a cylindrical dielectric wakefield accelerating structure as a coherent Cerenkov radiation source at the Neptune laboratory at UCLA. The Cerenkov wakefield acceleration experiment carried out recently by UCLA/SLAC/USC, using the ultrashort and high charge beam (Q = 3 nC, {sigma}z = 20 micron) at the SLAC FFTB, demonstrated electromagnetic wakes at the few GV/m level. The motivation of our prospective experiment is to investigate the operation of a similar scenario using the comparatively long pulse, low charge beam (Q = 0.5 nC, {sigma}z = 200 micron) at UCLA Neptune. The field amplitude produced in this setup would be one to two orders of magnitude lower, at the few tens to few 100 MV/m level. Such a decelerating field would extract a significant amount of energy from a low-energy beam in a distance on the order of a few centimeters, allowing the use of short dielectric structures. We discuss details of the geometry and composition of the structures to be used in the experiment. We also examine the possibility of a future dedicated facility at UCLA Neptune based on a hybrid photoinjector currently in development. The intrinsic bunch compression capabilities and improved beam parameters ({sigma}z = 100 micron, Q = 1 nC) of the photoinjector would allow the creation of a high power radiation source in the terahertz regime.

  7. High-power rf pulse compression with SLED-II at SLAC

    SciTech Connect

    Nantista, C.; Kroll, N.M.; Farkas, Z.D.; Lavine, T.L.; Menegat, A.; Ruth, R.D.; Tantawi, S.G.; Vlieks, A.E.; Wilson, P.B.

    1993-04-01

    Increasing the peak rf power available from X-band microwave tubes by means of rf pulse compression is envisioned as a way of achieving the few-hundred-megawatt power levels needed to drive a next-generation linear collider with 50--100 MW klystrons. SLED-II is a method of pulse compression similar in principal to the SLED method currently in use on the SLC and the LEP injector linac. It utilizes low-los resonant delay lines in place of the storage cavities of the latter. This produces the added benefit of a flat-topped output pulse. At SLAC, we have designed and constructed a prototype SLED-II pulse-compression system which operates in the circular TE{sub 01} mode. It includes a circular-guide 3-dB coupler and other novel components. Low-power and initial high-power tests have been made, yielding a peak power multiplication of 4.8 at an efficiency of 40%. The system will be used in providing power for structure tests in the ASTA (Accelerator Structures Test Area) bunker. An upgraded second prototype will have improved efficiency and will serve as a model for the pulse compression system of the NLCTA (Next Linear Collider Test Accelerator).

  8. Enabling Technologies for Petascale Electromagnetic Accelerator Simulation

    SciTech Connect

    Lee, Lie-Quan; Akcelik, Volkan; Chen, Sheng; Ge, Li-Xin; Prudencio, Ernesto; Schussman, Greg; Uplenchwar, Ravi; Ng, Cho; Ko, Kwok; Luo, Xiaojun; Shephard, Mark; /Rensselaer Poly.

    2007-11-09

    The SciDAC2 accelerator project at SLAC aims to simulate an entire three-cryomodule radio frequency (RF) unit of the International Linear Collider (ILC) main Linac. Petascale computing resources supported by advances in Applied Mathematics (AM) and Computer Science (CS) and INCITE Program are essential to enable such very large-scale electromagnetic accelerator simulations required by the ILC Global Design Effort. This poster presents the recent advances and achievements in the areas of CS/AM through collaborations.

  9. Development of X-band klystron technology at SLAC

    SciTech Connect

    Caryotakis, G.

    1997-05-01

    The SLAC design for a 1-TeV collider (NLC) requires klystrons with a performance which is well beyond the state-of-the-art for microwave tubes in the United States or abroad. The electrical specifications for the NLC klystrons are not fully established, but they are approximately as follows: Frequency, 11.4 GHz; Peak Power, 75 MW; Pulse Length, 1.5 {mu}s; Repetition Rate, 180 Hz; Gain, 50 dB; Efficiency, (including beam focusing) 50%. SLAC is in the seventh year of a program to develop these klystrons. The choice of X-band as the operating frequency, along with the sheer size of the NLC, have resulted in some new, most demanding standards for the klystrons which may power this future machine. These are related to the overall efficiency required, to the high rf gradients that must be supported at the output circuit without vacuum breakdown, and to the manufacturing cost of the 5,000-10,000 klystrons needed for the collider.

  10. Production and isolation of homologs of flerovium and element 115 at the Lawrence Livermore National Laboratory Center for Accelerator Mass Spectrometry

    DOE PAGESBeta

    Despotopulos, John D.; Kmak, Kelly N.; Gharibyan, Narek; Brown, Thomas A.; Grant, Patrick M.; Henderson, Roger A.; Moody, Kent J.; Tumey, Scott J.; Shaughnessy, Dawn A.; Sudowe, Ralf

    2015-10-01

    Here, new procedures have been developed to isolate no-carrier-added (NCA) radionuclides of the homologs and pseudo-homologs of flerovium (Hg, Sn) and element 115 (Sb), produced by 12–15 MeV proton irradiation of foil stacks with the tandem Van-de-Graaff accelerator at the Lawrence Livermore National Laboratory Center for Accelerator Mass Spectrometry (CAMS) facility. The separation of 113Sn from natIn foil was performed with anion-exchange chromatography from hydrochloric and nitric acid matrices. A cation-exchange chromatography method based on hydrochloric and mixed hydrochloric/hydroiodic acids was used to separate 124Sb from natSn foil. A procedure using Eichrom TEVA resin was developed to separate 197Hg frommore » Au foil. These results demonstrate the suitability of using the CAMS facility to produce NCA radioisotopes for studies of transactinide homologs.« less

  11. Production and isolation of homologs of flerovium and element 115 at the Lawrence Livermore National Laboratory Center for Accelerator Mass Spectrometry

    SciTech Connect

    Despotopulos, John D.; Kmak, Kelly N.; Gharibyan, Narek; Brown, Thomas A.; Grant, Patrick M.; Henderson, Roger A.; Moody, Kent J.; Tumey, Scott J.; Shaughnessy, Dawn A.; Sudowe, Ralf

    2015-10-01

    Here, new procedures have been developed to isolate no-carrier-added (NCA) radionuclides of the homologs and pseudo-homologs of flerovium (Hg, Sn) and element 115 (Sb), produced by 12–15 MeV proton irradiation of foil stacks with the tandem Van-de-Graaff accelerator at the Lawrence Livermore National Laboratory Center for Accelerator Mass Spectrometry (CAMS) facility. The separation of 113Sn from natIn foil was performed with anion-exchange chromatography from hydrochloric and nitric acid matrices. A cation-exchange chromatography method based on hydrochloric and mixed hydrochloric/hydroiodic acids was used to separate 124Sb from natSn foil. A procedure using Eichrom TEVA resin was developed to separate 197Hg from Au foil. These results demonstrate the suitability of using the CAMS facility to produce NCA radioisotopes for studies of transactinide homologs.

  12. World Pendulum--A Distributed Remotely Controlled Laboratory (RCL) to Measure the Earth's Gravitational Acceleration Depending on Geographical Latitude

    ERIC Educational Resources Information Center

    Grober, S.; Vetter, M.; Eckert, B.; Jodl, H.-J.

    2007-01-01

    We suggest that different string pendulums are positioned at different locations on Earth and measure at each place the gravitational acceleration (accuracy [delta]g is approximately equal to 0.01 m s[superscript -2]). Each pendulum can be remotely controlled via the internet by a computer located somewhere on Earth. The theoretical part describes…

  13. Elementary principles of linear accelerators

    NASA Astrophysics Data System (ADS)

    Loew, G. A.; Talman, R.

    1983-09-01

    A short chronology of important milestones in the field of linear accelerators is presented. Proton linacs are first discussed and elementary concepts such as transit time, shunt impedance, and Q are introduced. Critical issues such as phase stability and transverse forces are addressed. An elementary discussion of waveguide acclerating structures is also provided. Finally, electron accelerators addressed. Taking SLAC as an exmple, various topics are discussed such as structure design, choice of parameters, frequency optmization, beam current, emittance, bunch length and beam loading. Recent developments and future challenges are mentioned briefly.

  14. Centralized digital control of accelerators

    SciTech Connect

    Melen, R.E.

    1983-09-01

    In contrasting the title of this paper with a second paper to be presented at this conference entitled Distributed Digital Control of Accelerators, a potential reader might be led to believe that this paper will focus on systems whose computing intelligence is centered in one or more computers in a centralized location. Instead, this paper will describe the architectural evolution of SLAC's computer based accelerator control systems with respect to the distribution of their intelligence. However, the use of the word centralized in the title is appropriate because these systems are based on the use of centralized large and computationally powerful processors that are typically supported by networks of smaller distributed processors.

  15. Alteration of Arabidopsis SLAC1 promoter and its association with natural variation in drought tolerance.

    PubMed

    Imai, Hiroe; Noda, Yusaku; Tamaoki, Masanori

    2015-01-01

    Natural variation for drought tolerance is a major issue in adaptation and geographic distribution of terrestrial plants. Despite the importance, little is known about the genes and molecular mechanisms that determine its naturally occurring diversity. We analyzed the intraspecific drought tolerance variation between 2 accessions of Arabidopsis thaliana, Columbia (Col)-0 and Wassilewskija (Ws)-2. Measurement of weight loss in detached seedlings demonstrated a clear difference between drought-tolerant Col-0 and drought-sensitive Ws-2. They also differed in their stomatal response under drought condition. Using a quantitative genetic approach, we found a significant quantitative locus on chromosome 1. Surveying in the locus, we extrapolated that the SLAC1 gene, which is associated with stomatal closure, was likely responsible for the difference of drought tolerance. Comparison of their nucleotide and amino acid sequences revealed that there were few differences in regions encoding SLAC1 protein but was a large deletion in SLAC1 promoter of Ws-2. Histochemical GUS staining showed that the SLAC1 expressed dominantly in guard cells of Col-0, but did less in guard cells of Ws-2. Quantitative PCR analysis also showed that transcript level of SLAC1 in guard cells was higher in Col-0 than in Ws-2. The SLAC1 transcription analyses indicate low accumulation of SLAC1 in guard cells of Ws-2. When taken together, our results suggest that the low drought tolerance of Ws-2 was associated with the deletion of the promoter region of Ws-2 SLAC1. PMID:25695335

  16. 17 GHz High Gradient Accelerator Research

    SciTech Connect

    Temkin, Richard J.; Shapiro, Michael A.

    2013-07-10

    This is a report on the MIT High Gradient Accelerator Research program which has included: Operation of the 17 GHz, 25 MeV MIT/Haimson Research Corp. electron accelerator at MIT, the highest frequency, stand-alone accelerator in the world; collaboration with members of the US High Gradient Collaboration, including the design and test of novel structures at SLAC at 11.4 GHz; the design, construction and testing of photonic bandgap structures, including metallic and dielectric structures; the investigation of the wakefields in novel structures; and the training of the next generation of graduate students and postdoctoral associates in accelerator physics.

  17. Critical Issues in Plasma Accelerator

    NASA Astrophysics Data System (ADS)

    Uesaka, M.; Hosokai, T.

    2004-10-01

    Updated achievements and critical issues in plasma accelerators are summarized. As to laser plasma accelerators, we cover the results of plasma cathodes by U.Michigan, LBNL, LOA and U.Tokyo. Although many new results of accelerated electrons have been reported, the electrons do not yet form a bunch with narrow energy spread. Several injection schemes and measurements to verify ultrashort bunch (tens fs) with narrow energy spread, low emittance and many charges are planned. E-162 experiments by UCLA / USC / SLAC and a newly proposed experiment on density transition trapping are introduced for electron beam driven plasma accelerators. Their main purpose is realization of GeV plasma accelerator, but application to pump-and-probe analysis for investigation of ultrafast quantum phenomena is also promising.

  18. Accelerating technology transfer from federal laboratories to the private sector by industrial R and D collaborations - A new business model

    SciTech Connect

    LOMBANA,CESAR A.; ROMIG JR.,ALTON D.; LINTON,JONATHAN D.; MARTINEZ,J. LEONARD

    2000-04-13

    Many important products and technologies were developed in federal laboratories and were driven initially by national needs and for federal applications. For example, the clean room technology that enhanced the growth of the semiconductor industry was developed at Sandia National Laboratories (SNL) decades ago. Similarly, advances in micro-electro-mechanical-systems (MEMS)--an important set of process technologies vital for product miniaturization--are occurring at SNL. Each of the more than 500 federal laboratories in the US, are sources of R and D that contributes to America's economic vitality, productivity growth and, technological innovation. However, only a fraction of the science and technology available at the federal laboratories is being utilized by industry. Also, federal laboratories have not been applying all the business development processes necessary to work effectively with industry in technology commercialization. This paper addresses important factors that federal laboratories, federal agencies, and industry must address to translate these under utilized technologies into profitable products in the industrial sector.

  19. Research and Development Toward a 4.5-1.5 {Angstrom} Linac Coherent Light Source (LCLS) at SLAC

    SciTech Connect

    Tatchyn, R.; Arthur, J.; Baltay, M.

    1995-08-01

    In recent years significant studies have been initiated on the feasibility of utilizing a portion of the 3km S-band accelerator at SLAC to drive a short wavelength (4.5-1.5 A) Linac Coherent Light Source (LCLS), a Free Electron Laser (FEL) operating in the Self- Amplified Spontaneous Emission (SASE) regime. Electron beam requirements for single-pass saturation in a minimal time include: (1) a peak current in the 7 kA range, (2) a relative energy spread of {lt}0.05%, and (3) a transverse emittance, {epsilon}[r-m], approximating the diffraction limit condition {epsilon} = {lambda} / 4{pi}, where lambda(m) is the output wavelength. Requirements on the insertion device include field error levels of 0.02% for keeping the electron bunch centered on and in phase with the amplified photons, and a focusing beta of 8 m/rad for inhibiting the dilution of its transverse density. Although much progress has been made in developing individual components and beam processing techniques necessary for LCLS operation down to approx. 20 A, a substantial amount of research and development is still required in a number of theoretical and experimental areas leading to the construction and operation of a 4.5-1.5 A LCLS. In this paper we report on a research and development program underway and in planning at SLAC for addressing critical questions in these areas.

  20. SLAC All Access: Atomic, Molecular and Optical Science Instrument

    SciTech Connect

    Bozek, John

    2013-11-05

    John Bozek, a staff scientist at SLAC's Linac Coherent Light Source (LCLS) X-ray laser who manages the LCLS Soft X-ray Department, takes us behind the scenes at the Atomic, Molecular and Optical Science (AMO) instrument, the first of six experimental stations now operating at LCLS. Samples used in AMO experiments include atoms, molecules, clusters, and nanoscale objects such as protein crystals or viruses. Science performed at AMO includes fundamental studies of light-matter interactions in the extreme X-ray intensity of the LCLS pules, time-resolved studies of increasingly charged states of atoms and molecules, X-ray diffraction imaging of nanocrystals, and single-shot imaging of a variety of objects.

  1. SLAC All Access: Atomic, Molecular and Optical Science Instrument

    ScienceCinema

    Bozek, John

    2014-06-03

    John Bozek, a staff scientist at SLAC's Linac Coherent Light Source (LCLS) X-ray laser who manages the LCLS Soft X-ray Department, takes us behind the scenes at the Atomic, Molecular and Optical Science (AMO) instrument, the first of six experimental stations now operating at LCLS. Samples used in AMO experiments include atoms, molecules, clusters, and nanoscale objects such as protein crystals or viruses. Science performed at AMO includes fundamental studies of light-matter interactions in the extreme X-ray intensity of the LCLS pules, time-resolved studies of increasingly charged states of atoms and molecules, X-ray diffraction imaging of nanocrystals, and single-shot imaging of a variety of objects.

  2. Physics prospects for the SLAC B-Factory

    SciTech Connect

    Coward, D.H.

    1996-11-01

    CP violation has been an enigma since its discovery in the decays of neutral kaons in 1964. The present version of the Standard Model can accommodate CP violation by means of a non-zero phase in the Cabibbo-Kobayashi-Maskawa (CKM) matrix. However, CP violation in the kaon system occurs at the part per mille level and the Standard Model`s predictions for CP violation have not been conclusively tested. In contrast to the kaon system, B-mesons decay into a variety of final states, many of which could exhibit CP violation and therefore offer multiple tests of the Standard Model. Several large efforts currently are in progress to create dedicated experiments or factories which will provide large quantities of B-mesons which, in turn, should give large numbers of CP-violating decays. Here, a very brief presentation of the physics prospects for the SLAC B-Factory, now under construction, is presented.

  3. A damping ring design for the SLAC Next Linear Collider

    SciTech Connect

    Raubenheimer, T.O.; Byrd, J.; Corlett, J.

    1995-05-01

    In this paper, we describe the design of the main damping rings and the positron pre-damping ring for the SLAC Next Linear Collider, a future linear collider with a center-of-mass energy of 0.5 to 1.5 TeV. The rings will operate at an energy of 2 GeV with a maximum repetition rate of 180 Hz. The normalized extracted beam emittances are {gamma}{epsilon}{sub x} = 3 mm-mrad and {gamma}{epsilon}{sub y} = 0.03 mm-mrad. To provide the necessary damping, the rings must damp multiple trains of bunches. Thus, the beam current is large, roughly 1 A. We will present the optical layout, magnet designs, and RF systems, along with the dynamic aperture and required alignment tolerances; collective effects will be discussed in another paper.

  4. Compact x-ray lasers in the laboratory

    SciTech Connect

    Barletta, W.A.

    1988-10-03

    Compact x-ray lasers in the laboratory can be produced with ultrahigh gradient rf linacs based on recent advances in linac technology by an SLAC-LLNL-LBL collaboration and on the development of bright, high current electron sources by BNL and LANL. The GeV electron beams generated with such accelerators can be converted to soft x rays in the range of 2--10 nm by passage through short period, high field strength wigglers. Alternatively, the beam can pump a low density dielectric to produce x rays via recombination. Such linear light sources can produce trains of picosecond (or shorter) pulses of extremely high spectral brilliance suitable for flash holography of biological specimens in vivo and for studies of fast chemical reactions. 15 refs., 7 figs., 3 tabs.

  5. Accelerating Ocean Energy to the Marketplace – Environmental Research at the U.S. Department of Energy National Laboratories

    SciTech Connect

    Copping, Andrea E.; Cada, G. F.; Roberts, Jesse; Bevelhimer, Mark

    2010-10-06

    The U.S. Department of Energy (US DOE) has mobilized its National Laboratories to address the broad range of environmental effects of ocean and river energy development. The National Laboratories are using a risk-based approach to set priorities among environmental effects, and to direct research activities. Case studies will be constructed to determine the most significant environmental effects of ocean energy harvest for tidal systems in temperate estuaries, for wave energy installations in temperate coastal areas, wave installations in sub-tropical waters, and riverine energy installations in large rivers. In addition, the National Laboratories are investigating the effects of energy removal from waves, tides and river currents using numerical modeling studies. Laboratory and field research is also underway to understand the effects of electromagnetic fields (EMF), acoustic noise, toxicity from anti-biofouling coatings, effects on benthic habitats, and physical interactions with tidal and wave devices on marine and freshwater organisms and ecosystems. Outreach and interactions with stakeholders allow the National Laboratories to understand and mitigate for use conflicts and to provide useful information for marine spatial planning at the national and regional level.

  6. SLAC users Bulletin No. 96, August-December 1983

    SciTech Connect

    Keller, L. P.; Edminster, D.

    1983-01-01

    Operational activities for the months of August through December 1983, are reported in the areas of accelerator and research operations, research area and experiment status, accelerator improvements, research division developments, PEP division developments, and publications for the month. (GHT)

  7. Loss-of-function mutation of rice SLAC7 decreases chloroplast stability and induces a photoprotection mechanism in rice.

    PubMed

    Fan, Xiaolei; Wu, Jiemin; Chen, Taiyu; Tie, Weiwei; Chen, Hao; Zhou, Fei; Lin, Yongjun

    2015-12-01

    Plants absorb sunlight to power the photochemical reactions of photosynthesis, which can potentially damage the photosynthetic machinery. However, the mechanism that protects chloroplasts from the damage remains unclear. In this work, we demonstrated that rice (Oryza sativa L.) SLAC7 is a generally expressed membrane protein. Loss-of-function of SLAC7 caused continuous damage to the chloroplasts of mutant leaves under normal light conditions. Ion leakage indicators related to leaf damage such as H2 O2 and abscisic acid levels were significantly higher in slac7-1 than in the wild type. Consistently, the photosynthesis efficiency and Fv/Fm ratio of slac7-1 were significantly decreased (similar to photoinhibition). In response to chloroplast damage, slac7-1 altered its leaf morphology (curled or fused leaf) by the synergy between plant hormones and transcriptional factors to decrease the absorption of light, suggesting that a photoprotection mechanism for chloroplast damage was activated in slac7-1. When grown in dark conditions, slac7-1 displayed a normal phenotype. SLAC7 under the control of the AtSLAC1 promoter could partially complement the phenotypes of Arabidopsis slac1 mutants, indicating a partial conservation of SLAC protein functions. These results suggest that SLAC7 is essential for maintaining the chloroplast stability in rice. PMID:25739330

  8. Collaborative Visualization for Large-Scale Accelerator Electromagnetic Modeling (Final Report)

    SciTech Connect

    William J. Schroeder

    2011-11-13

    This report contains the comprehensive summary of the work performed on the SBIR Phase II, Collaborative Visualization for Large-Scale Accelerator Electromagnetic Modeling at Kitware Inc. in collaboration with Stanford Linear Accelerator Center (SLAC). The goal of the work was to develop collaborative visualization tools for large-scale data as illustrated in the figure below. The solutions we proposed address the typical problems faced by geographicallyand organizationally-separated research and engineering teams, who produce large data (either through simulation or experimental measurement) and wish to work together to analyze and understand their data. Because the data is large, we expect that it cannot be easily transported to each team member's work site, and that the visualization server must reside near the data. Further, we also expect that each work site has heterogeneous resources: some with large computing clients, tiled (or large) displays and high bandwidth; others sites as simple as a team member on a laptop computer. Our solution is based on the open-source, widely used ParaView large-data visualization application. We extended this tool to support multiple collaborative clients who may locally visualize data, and then periodically rejoin and synchronize with the group to discuss their findings. Options for managing session control, adding annotation, and defining the visualization pipeline, among others, were incorporated. We also developed and deployed a Web visualization framework based on ParaView that enables the Web browser to act as a participating client in a collaborative session. The ParaView Web Visualization framework leverages various Web technologies including WebGL, JavaScript, Java and Flash to enable interactive 3D visualization over the web using ParaView as the visualization server. We steered the development of this technology by teaming with the SLAC National Accelerator Laboratory. SLAC has a computationally-intensive problem

  9. Relativistic electron acceleration by compressional-mode ULF waves: Evidence from correlated Cluster, Los Alamos National Laboratory spacecraft, and ground-based magnetometer measurements

    NASA Astrophysics Data System (ADS)

    Tan, Lun C.; Shao, X.; Sharma, A. S.; Fung, Shing F.

    2011-07-01

    Simultaneous observations by Cluster and Los Alamos National Laboratory (LANL) spacecraft and Canadian Array for Real-Time Investigations of Magnetic Activity and International Monitor for Auroral Geomagnetic Effects magnetometer arrays during a sudden storm commencement on 25 September 2001 show evidence of relativistic electron acceleration by compressional-mode ULF waves. The waves are driven by the quasiperiodic solar wind dynamical pressure fluctuations that continuously buffet the magnetosphere for ˜3 h. The compressional-mode ULF waves are identified by comparing the power of magnetic field magnitude fluctuations with the total magnetic field power. The radial distribution and azimuthal propagation of both toroidal and poloidal-mode ULF waves are derived from ground-based magnetometer data. The energetic electron fluxes measured by LANL show modulation of low-energy electrons and acceleration of high-energy electrons by the compressional poloidal-mode electric field oscillations. The energy threshold of accelerated electrons at the geosynchronous orbit is ˜0.4 MeV, which is roughly consistent with drift-resonant interaction of magnetospheric electrons with compressional-mode ULF waves.

  10. Statistical correlation of the soil incubation and the accelerated laboratory extraction methods to estimate nitrogen release rates of slow- and controlled-release fertilizers.

    PubMed

    Medina, L Carolina; Sartain, Jerry; Obreza, Thomas; Hall, William L; Thiex, Nancy J

    2014-01-01

    Several technologies have been proposed to characterize the nutrient release patterns of enhanced-efficiency fertilizers (EEFs) during the last few decades. These technologies have been developed mainly by manufacturers and are product-specific based on the regulation and analysis of each EEF product. Despite previous efforts to characterize nutrient release of slow-release fertilizer (SRF) and controlled-release fertilizer (CRF) materials, no official method exists to assess their nutrient release patterns. However, the increased production and distribution of EEFs in specialty and nonspecialty markets requires an appropriate method to verify nutrient claims and material performance. Nonlinear regression was used to establish a correlation between the data generated from a 180-day soil incubation-column leaching procedure and 74 h accelerated lab extraction method, and to develop a model that can predict the 180-day nitrogen (N) release curve for a specific SRF and CRF product based on the data from the accelerated laboratory extraction method. Based on the R2 > 0.90 obtained for most materials, results indicated that the data generated from the 74 h accelerated lab extraction method could be used to predict N release from the selected materials during 180 days, including those fertilizers that require biological activity for N release. PMID:25051612

  11. Recent Measurements And Plans for the SLAC Compton X-Ray Source

    SciTech Connect

    Vlieks, A.E.; Akre, R.; Caryotakis, G.; DeStefano, C.; Frederick, W.J.; Heritage, J.P.; Luhmann, N.C.; Martin, D.; Pellegrini, C.; /SLAC /UC, Davis /UCLA

    2006-02-14

    A compact source of monoenergetic X-rays, generated via Compton backscattering, has been developed in a collaboration between U.C Davis and SLAC. The source consists of a 5.5 cell X-band photoinjector, a 1.05 m long high gradient accelerator structure and an interaction chamber where a high power (TW), short pulse (sub-ps) infrared laser beam is brought into a nearly head-on collision with a high quality focused electron beam. Successful completion of this project will result in the capability of generating a monoenergetic X-ray beam, continuously tunable from 20 - 85 keV. We have completed a series of measurements leading up to the generation of monoenergetic X-rays. Measurements of essential electron beam parameters and the techniques used in establishing electron/photon collisions will be presented. We discuss the design of an improved interaction chamber, future electro-optic experiments using this chamber and plans for expanding the overall program to the generation of Terahertz radiation.

  12. Recent Measurements and Plans for the SLAC Compton X- Ray Source

    SciTech Connect

    Vlieks, A. E.; Akre, R.; Caryotakis, G.; Martin, D.; DeStefano, C.; Frederick, W. J.; Heritage, J. P.; Luhmann, N. C. Jr.; Pellegrini, C.

    2006-01-03

    A compact source of monoenergetic x-rays, generated via Compton backscattering, has been developed in a collaboration between UC Davis and SLAC. The source consists of a 5.5 cell X-band photoinjector, a 1.05 m long high gradient accelerator structure and an interaction chamber where a high power (TW), short pulse (sub-ps) infrared laser beam is brought into a nearly head-on collision with a high quality focused electron beam. Successful completion of this project will result in the capability of generating a monoenergetic x-ray beam, continuously tunable from 20 - 85 keV.We have completed a series of measurements leading up to the generation of monoenergetic X-rays. Measurements of essential electron beam parameters and the techniques used in establishing electron/photon collisions will be presented.We discuss the design of an improved interaction chamber, future electro-optic experiments using this chamber and plans for expanding the overall program to the generation of Terahertz radiation.

  13. Performance of the PEP-II B-Factory Collider at SLAC

    SciTech Connect

    Seeman, J.; Browne, M.; Cai, Y.; Colocho, W.; Decker, F.J.; Donald, M.H.; Ecklund, S.; Erickson, R.A.; Fisher, A.S.; Fox, J.D.; Heifets, S.A.; Iverson, R.H.; Kulikov, A.; Li, N.; Novokhatski, A.; Ross, M.C.; Schuh, P.; Smith, T.J.; Sonnad, K.G.; Stanek, M.; Sullivan, M.K.; /SLAC /Frascati /DSM, DAPNIA, Saclay /LBL, Berkeley /Orsay, IPN

    2006-03-03

    PEP-II is an e{sup +}e{sup -} asymmetric B-Factory Collider located at SLAC operating at the Upsilon 4S resonance (3.1 GeV x 9 GeV). It has reached a luminosity of 9.21 x 10{sup 33}/cm{sup 2}/s and has delivered an integrated luminosity of 710 pb{sup -1} in one day. PEP-II has delivered, over the past six years, an integrated luminosity to the BaBar detector of over 262 fb{sup -1}. PEP-II operates in continuous injection mode for both beams boosting the integrated luminosity. The peak positron current has reached 2.45 A in 1588 bunches. Steady progress is being made in reaching higher luminosity. The goal over the next several years is to reach a luminosity of 2.1 x 10{sup 34}/cm{sup 2}/s. The accelerator physics issues being addressed in PEP-II to reach this goal include the electron cloud instability, beam-beam effects, parasitic beam-beam effects, high RF beam loading, shorter bunches, lower {beta}*{sub y} interaction region operation, and coupling control. Figure 1 shows the PEP-II tunnel.

  14. Accelerators for America's Future

    NASA Astrophysics Data System (ADS)

    Bai, Mei

    2016-03-01

    Particle accelerator, a powerful tool to energize beams of charged particles to a desired speed and energy, has been the working horse for investigating the fundamental structure of matter and fundermental laws of nature. Most known examples are the 2-mile long Stanford Linear Accelerator at SLAC, the high energy proton and anti-proton collider Tevatron at FermiLab, and Large Hadron Collider that is currently under operation at CERN. During the less than a century development of accelerator science and technology that led to a dazzling list of discoveries, particle accelerators have also found various applications beyond particle and nuclear physics research, and become an indispensible part of the economy. Today, one can find a particle accelerator at almost every corner of our lives, ranging from the x-ray machine at the airport security to radiation diagnostic and therapy in hospitals. This presentation will give a brief introduction of the applications of this powerful tool in fundermental research as well as in industry. Challenges in accelerator science and technology will also be briefly presented

  15. The erosion of the beaches on the coast of Alicante: Study of the mechanisms of weathering by accelerated laboratory tests.

    PubMed

    López, I; López, M; Aragonés, L; García-Barba, J; López, M P; Sánchez, I

    2016-10-01

    One of the main problems that coasts around the world present, is the regression and erosion of beaches. However, the factors involved in these processes are unclear. In this study, the influence of sediment erosion on beach regression has been analysed. In order to do that, a three-step investigation has been carried out. Firstly, coastline variations of four Spanish beaches have been analysed. Secondly, a study on sediment position along the beach profile has been developed. Finally, the process that beach sediments undergo along the surf zone when they are hit by the incident waves has been simulated by an accelerated particle weathering test. Samples of sand and shells were subjected to this accelerated particle weathering test. Results were supplemented with those from carbonate content test, XRD, SEM and granulometric analysis. Results shows a cross-shore classification of sediments along the beach profile in which finer particles move beyond offshore limit. Besides, it was observed that sediment erosion process is divided into three sages: i) particles wear due to crashes ii) dissolution of the carbonate fraction, and iii) breakage and separation of mineral and carbonate parts of particles. All these processes lead to a reduction of particle size. The mechanism responsible of beach erosion would consist of multiples and continuous particle location exchanges along the beach profile as a consequence of grain-size decrease due to erosion. PMID:27220096

  16. EDITORIAL: Laser and plasma accelerators Laser and plasma accelerators

    NASA Astrophysics Data System (ADS)

    Bingham, Robert

    2009-02-01

    This special issue on laser and plasma accelerators illustrates the rapid advancement and diverse applications of laser and plasma accelerators. Plasma is an attractive medium for particle acceleration because of the high electric field it can sustain, with studies of acceleration processes remaining one of the most important areas of research in both laboratory and astrophysical plasmas. The rapid advance in laser and accelerator technology has led to the development of terawatt and petawatt laser systems with ultra-high intensities and short sub-picosecond pulses, which are used to generate wakefields in plasma. Recent successes include the demonstration by several groups in 2004 of quasi-monoenergetic electron beams by wakefields in the bubble regime with the GeV energy barrier being reached in 2006, and the energy doubling of the SLAC high-energy electron beam from 42 to 85 GeV. The electron beams generated by the laser plasma driven wakefields have good spatial quality with energies ranging from MeV to GeV. A unique feature is that they are ultra-short bunches with simulations showing that they can be as short as a few femtoseconds with low-energy spread, making these beams ideal for a variety of applications ranging from novel high-brightness radiation sources for medicine, material science and ultrafast time-resolved radiobiology or chemistry. Laser driven ion acceleration experiments have also made significant advances over the last few years with applications in laser fusion, nuclear physics and medicine. Attention is focused on the possibility of producing quasi-mono-energetic ions with energies ranging from hundreds of MeV to GeV per nucleon. New acceleration mechanisms are being studied, including ion acceleration from ultra-thin foils and direct laser acceleration. The application of wakefields or beat waves in other areas of science such as astrophysics and particle physics is beginning to take off, such as the study of cosmic accelerators considered

  17. Accelerator structure work for NLC

    SciTech Connect

    Miller, R.H.; Adolphsen, C.; Bane, K.L.F.; Deruyter, H.; Farkas, Z.D.; Hoag, H.A.; Holtkamp, N.; Lavine, T.; Loew, G.A.; Nelson, E.M.; Palmer, R.B.; Paterson, J.M.; Ruth, R.D.; Thompson, K.A.; Vlieks, A.; Wang, J.W.; Wilson, P.B. ); Gluckstern, R. ); Ko, K.; Kroll, N. (Stanford Linear Accelerator Ce

    1992-07-01

    The NLC design achieves high luminosity with multiple bunches in each RF pulse. Acceleration of a train of bunches without emittance growth requires control of long range dipole wakefields. SLAC is pursuing a structure design which suppresses the effect of wakefields by varying the physical dimensions of successive cells of the disk-loaded traveling wave structure in a manner which spreads the frequencies of the higher mode while retaining the synchronism between the electrons and the accelerating mode. The wakefields of structures incorporating higher mode detuning have been measured at the Accelerator Test Facility at Argonne. Mechanical design and brazing techniques which avoid getting brazing alloy into the interior of the accelerator are being studied. A test facility for high-power testing of these structures is complete and high power testing has begun.

  18. Research and development toward a 4.5-1.5{angstrom} linac coherent light source (LCLS) at SLAC

    SciTech Connect

    Tatchyn, R.; Arthur, J.; Baltay, M.

    1995-12-31

    In recent years significant studies have been initiated on the theoretical and technical feasibility of utilizing a portion of the 3km S-band accelerator at the Stanford Linear Accelerator Center (SLAC) to drive a short wavelength (4.5-1.5 {Angstrom}) Linac Coherent Light Source (LCLS), a Free-Electron Laser (FEL) operating in the Self-Amplified Spontaneous Emission (SASE) regime. Electron beam requirements for single-pass saturation include: (1) a peak current in the 3-7 kA range, (2) a relative energy spread of <0.05%, ad (3) a transverse emittance, {epsilon}{le}{lambda}/4{pi}, where {lambda}[m] is the output wavelength. Requirements on the insertion device include field error levels of 0.1-0.2% for keeping the electron bunch centered on and in phase with the amplified photons, and a focusing beta of 4-8 m for inhibiting the dilution of its transverse density. Although much progress techniques necessary for LCLS operation down to {approximately}20 {angstrom}, a substantial amount of research and development is still required in a number of theoretical and experimental areas leading to the construction and operation of a 4.5-1.5 {angstrom} LCLS. In this paper we report on a research and development program underway and in planning at SLAC for addressing critical questions in these areas. These include the construction and operation of a linac test stand for developing laser-driven photocathode rf guns with normalized emittances approaching 1 mm-mr; development of advanced beam compression, stability, an emittance control techniques at multi-GeV energies; the construction and operation of a FEL Amplifier Test Experiment (FATE) for theoretical and experimental studies of SASE at IR wavelengths; an undulator development program to investigate superconducting, hybrid/permanent magnet (hybrid/PM), and pulsed-Cu technologies; theoretical and computational studies of high-gain FEL physics and LCLS component designs.

  19. Accelerator mass spectrometry of 63Ni using a gas-filled magnet at the Munich Tandem Laboratory

    NASA Astrophysics Data System (ADS)

    Rugel, G.; Faestermann, T.; Knie, K.; Korschinek, G.; Marchetti, A. A.; McAninch, J. E.; Rühm, W.; Straume, T.; Wallner, C.

    2000-10-01

    The detection of 63Ni ( T1/2=100.1 yr) by means of accelerator mass spectrometry (AMS) using a gas-filled magnet (GFM) is described. The experimental setup includes a dedicated ion source, a 14 MV MP tandem, a GFM and a multi-anode ionization chamber. First results indicate a background level of 63Ni/Ni ratios as low as 2×10 -14. This sensitivity will allow - for the first time ever - to detect 63Ni induced by fast neutrons in copper samples from Hiroshima and Nagasaki, even for distances beyond 1500 m from the hypocenters. Thus, it will be possible to reconstruct experimentally the neutron doses of the A-bomb survivors from Hiroshima and Nagasaki.

  20. Next linear collider test accelerator injector upgrade

    SciTech Connect

    Yeremian, A.D.; Miller, R.H.

    1995-12-31

    The Next Linear Collider Test Accelerator (NLCTA) is being constructed at SLAC to demonstrate multibunch beam loading compensation, suppression of higher order deflecting modes and measure transverse components of the accelerating fields in X-band accelerating structures. Currently a simple injector which provides the average current necessary for the beam loading compensations studies is under construction. An injector upgrade is planned to produce bunch trains similar to that of the NLC with microbunch intensity, separation and energy spread, identical to that of NLC. We discuss the design of the NLCTA injector upgrade.

  1. Homologue Structure of the SLAC1 Anion Channel for Closing Stomata in Leaves

    SciTech Connect

    Y Chen; L Hu; M Punta; R Bruni; B Hillerich; B Kloss; B Rost; J Love; S Siegelbaum; W Hendrickson

    2011-12-31

    The plant SLAC1 anion channel controls turgor pressure in the aperture-defining guard cells of plant stomata, thereby regulating the exchange of water vapour and photosynthetic gases in response to environmental signals such as drought or high levels of carbon dioxide. Here we determine the crystal structure of a bacterial homologue (Haemophilus influenzae) of SLAC1 at 1.20 {angstrom} resolution, and use structure-inspired mutagenesis to analyse the conductance properties of SLAC1 channels. SLAC1 is a symmetrical trimer composed from quasi-symmetrical subunits, each having ten transmembrane helices arranged from helical hairpin pairs to form a central five-helix transmembrane pore that is gated by an extremely conserved phenylalanine residue. Conformational features indicate a mechanism for control of gating by kinase activation, and electrostatic features of the pore coupled with electrophysiological characteristics indicate that selectivity among different anions is largely a function of the energetic cost of ion dehydration.

  2. Support and utilization of the LSI-11 processor family at SLAC

    SciTech Connect

    Kieffer, J.; Logg, C.A.; Farwell, D.E.

    1981-01-01

    Microcomputer systems based on the DEC LSI-11 processor family have been in use at SLAC for five years. They are used for a wide variety of applications. The support of these systems is divided into three general areas: engineering, maintenance, and software. Engineering specifies the system to match user requirements. SLAC has been able to design one general purpose system which can be tailored to fit many specific requirements. Maintenance provides system and component diagnostic services and repair. Software support includes software consulting services, assistance in systems design, and the development and support of special purpose operating systems and programs. These support functions are handled as subtasks by three teams in the SLAC Electronics Instrumentation Group. Each of these teams utilizes several LSI-11 systems in the performance of its primary tasks. They work closely together to jointly provide overall support for the larger SLAC community.

  3. Design of a hard X-ray beamline and end-station for pump and probe experiments at Pohang Accelerator Laboratory X-ray Free Electron Laser facility

    NASA Astrophysics Data System (ADS)

    Park, Jaeku; Eom, Intae; Kang, Tai-Hee; Rah, Seungyu; Nam, Ki Hyun; Park, Jaehyun; Kim, Sangsoo; Kwon, Soonam; Park, Sang Han; Kim, Kyung Sook; Hyun, Hyojung; Kim, Seung Nam; Lee, Eun Hee; Shin, Hocheol; Kim, Seonghan; Kim, Myong-jin; Shin, Hyun-Joon; Ahn, Docheon; Lim, Jun; Yu, Chung-Jong; Song, Changyong; Kim, Hyunjung; Noh, Do Young; Kang, Heung Sik; Kim, Bongsoo; Kim, Kwang-Woo; Ko, In Soo; Cho, Moo-Hyun; Kim, Sunam

    2016-02-01

    The Pohang Accelerator Laboratory X-ray Free Electron Laser project, a new worldwide-user facility to deliver ultrashort, laser-like x-ray photon pulses, will begin user operation in 2017 after one year of commissioning. Initially, it will provide two beamlines for hard and soft x-rays, respectively, and two experimental end-stations for the hard x-ray beamline will be constructed by the end of 2015. This article introduces one of the two hard x-ray end-stations, which is for hard x-ray pump-probe experiments, and primarily outlines the overall design of this end-station and its critical components. The content of this article will provide useful guidelines for the planning of experiments conducted at the new facility.

  4. Evaluation of a commercial system for CAMAC-based control of the Chalk River Laboratories tandem-accelerator-superconducting-cyclotron complexcomplex

    SciTech Connect

    Greiner, B.F.; Caswell, D.J.; Slater, W.R. )

    1992-04-01

    This paper discusses the control system of the Tandem Accelerator Superconducting Cyclotron (TASCC) of AECL Research at its Chalk River Laboratories which is presently based on a PDP-11 computer and the IAS operating system. The estimated expense of a custom conversion of the system to a current, equivalent operating system is prohibitive. The authors have evaluated a commercial control package from VISTA Control Systems based on VAX microcomputers and the VMS operating system. Vsystem offers a modern, graphical operator interface, an extensive software toolkit for configuration of the system and a multi-feature data-logging capability, all of which far surpass the functionality of the present control system. However, the implementation of some familiar, practical features that TASCC operators find to be essential has proven to be challenging. The assessment of Vsystem, which is described in terms of presently perceived strengths and weaknesses, is, on balance, very positive.

  5. Beam Profile Monitor Tests at the SLAC FFTB^1

    NASA Astrophysics Data System (ADS)

    Norem, J.; Dawson, J.; Haberichter, W.; Reed, L.; Yang, X.-F.; Spencer, J.; Saleski, M.

    1996-05-01

    The next generation linear colliders require beam sizes as small as 5 nm for efficient collisions between electron and positron beams. The difficulty of producing and maintaining such beams in stable collision means that bunch-to-bunch measurements need to be made quickly and precisely. We are developing a new technique using non-imaging gamma optics having good time resolution and sensitivity to correlations when the expected resolution is a few nm. Apparatus has been set up and made operational in the Final Focus Test Beam at SLAC and we have begun to tune and test components. We will describe this setup and our initial measurements together with Monte Carlo simulations based on using foils and wires (bremsstrahlung) and laser backscattering (Compton) as gamma sources to measure the beam size at IP1 of experiment E144. For the NLC we could also use beamsstrahlung generated by the strong beam-beam interaction at the IP to provide a comparable nonintercepting monitor. \\overline ^1Funded by the US Department of Energy under contracts W-31-109-ENG-38 and DE-AC03-76SF00515.

  6. Measurements of the neutron polarized structure function at SLAC

    SciTech Connect

    Young, C.C.; E-142 Collaboration

    1995-08-01

    Detailed measurements of unpolarized or spin-averaged nucleon structure functions over the past two decades have led to detailed knowledge of the nucleon`s internal momentum distribution. Polarized nucleon structure function measurements, which probe the nucleon`s internal spin distribution, started at SLAC in 1976. E-142 has recently measured the neutron polarized structure function g{sub 1}{sup n}(x) over the range 0.03 {le} {times} {le} 0.6 at an average Q{sup 2} of 2 GeV{sup 2} and found the integral I{sup n} = {integral}{sub 0}{sup 1}g{sub 1}{sup n}(x)dx={minus}0.022{plus_minus}0.011. E-143, which took data recently, has measured g{sub 1}{sup p} and g{sub 1}{sup 4}. Two more experiments (E-154 and E-155) will extend these measurements to lower x and higher Q{sup 2}.

  7. A hybrid anode reactor for the SLAC modulator

    SciTech Connect

    Donaldson, A.R.

    1994-06-01

    The SLAC modulators operate at 150 MW ak outputs at 120 pps with an average power of 87 kW. In an effect to improve modulator performance and reliability, we describe the design of a hybrid anode reactor using ferrite to decrease the ringing of the output pulse, and incidentally reduce thyratron commutation loss. The design uses MnZn ferrite as a saturable lossy element to decrease the ringing in combination with NiZn ferrite as a saturable reactor for reducing the switching loss. The output ringing is product of the PFN stray capacitance and the leakage inductance of the pulse transformer, and if not suppressed causes premature failures of the output cable. The saturable switch aspect then offers the necessary rise time and pulse width recovery. While these two goals seem contrary, our initial performance objectives were met Ringing on the output pulse is decreased by 50%. Switching loss reduction is measured by a thyratron temperature decrease of 15% as measured on the anode with a cathode reference temperature. The reactor packaging is very simple, and it is separated from the thyratron space so not to complicate thyratron replacement or modulator repairs and maintenance.

  8. SLAC P2 Marx Control System and Regulation Scheme

    SciTech Connect

    MacNair, David; Kemp, Mark A.; Macken, Koen; Nguyen, Minh N.; Olsen, Jeff; /SLAC

    2011-05-20

    The SLAC P2 MARX Modulator consists of 32 cells charged in parallel by a -4 kV supply and discharged in series to provide a -120 kV 140 amp 1.7 millisecond pulse. Each cell has a 350 uF main storage capacitor. The voltage on the capacitor will droop approximately 640 volts during each pulse. Each cell will have a boost supply that can add up to 700 V to the cell output. This allows the output voltage of the cell to remain constant within 0.1% during the pulse. The modulator output voltage control is determined by the -4 kV charging voltage. A voltage divider will measure the modulator voltage on each pulse. The charging voltage will be adjusted by the data from previous pulses to provide the desired output. The boost supply in each cell consists of a 700 V buck regulator in series with the main capacitor. The supply uses a lookup table for PWM control. The lookup table is calculated from previous pulse data to provide a constant cell output. The paper will describe the modulator and cell regulation used by the MARX modulator. Measured data from a single cell and three cell string will be included.

  9. The new external microbeam facility at the 5 MV Tandetron accelerator laboratory in Madrid: beam characterisation and first results

    NASA Astrophysics Data System (ADS)

    Enguita, Olga; Fernández-Jiménez, M. T.; García, G.; Climent-Font, A.; Calderón, T.; Grime, G. W.

    2004-06-01

    This paper describes the new external microbeam on the 15° beamline of the 5 MV Tandetron accelerator recently installed at the CMAM in Madrid. The focusing and beam extraction system was supplied by Oxford Microbeams Ltd. and consists of a high precision quadrupole doublet with an interchangeable Kapton window exit nozzle and front-viewing video microscope. The sample is positioned in the beam using a stepper motor stage. The beam current and beam profile have been determined under different experimental conditions. A simple method based on the signal processing of ion-induced luminescence from quartz targets has been used to determine the beam profile in two dimensions simultaneously, without scanning. This is the first step in the development of a real time beam profile monitoring system, which could be used as part of an automated beam focusing procedure. The beam line will be primarily devoted to archaeometry and cultural heritage studies. As an example we report the characterisation of two Tang appearance antique porcelains.

  10. A Possible CO2 Conducting and Concentrating Mechanism in Plant Stomata SLAC1 Channel

    PubMed Central

    Du, Qi-Shi; Fan, Xina-Wei; Wang, Cheng-Hua; Huang, Ri-Bo

    2011-01-01

    Background The plant SLAC1 is a slow anion channel in the membrane of stomatal guard cells, which controls the turgor pressure in the aperture-defining guard cells, thereby regulating the exchange of water vapour and photosynthetic gases in response to environmental signals such as drought, high levels of carbon dioxide, and bacterial invasion. Recent study demonstrated that bicarbonate is a small-molecule activator of SLAC1. Higher CO2 and HCO3– concentration activates S-type anion channel currents in wild-type Arabidopsis guard cells. Based on the SLAC1 structure a theoretical model is derived to illustrate the activation of bicarbonate to SLAC1 channel. Meanwhile a possible CO2 conducting and concentrating mechanism of the SLAC1 is proposed. Methodology The homology structure of Arabidopsis thaliana SLAC1 (AtSLAC1) provides the structural basis for study of the conducting and concentrating mechanism of carbon dioxide in SLAC1 channels. The pKa values of ionizable amino acid side chains in AtSLAC1 are calculated using software PROPKA3.0, and the concentration of CO2 and anion HCO3– are computed based on the chemical equilibrium theory. Conclusions The AtSLAC1 is modeled as a five-region channel with different pH values. The top and bottom layers of channel are the alkaline residue-dominated regions, and in the middle of channel there is the acidic region surrounding acidic residues His332. The CO2 concentration is enhanced around 104 times by the pH difference between these regions, and CO2 is stored in the hydrophobic region, which is a CO2 pool. The pH driven CO2 conduction from outside to inside balances the back electromotive force and maintain the influx of anions (e.g. Cl– and NO3–) from inside to outside. SLAC1 may be a pathway providing CO2 for photosynthesis in the guard cells. PMID:21931667

  11. Some initial results from the new SLAC (Stanford Linear Accelerator Center) permeameter

    SciTech Connect

    Cobb, J.K.; Early, R.A.

    1990-01-01

    A new permeameter has been built and is now available for testing samples of steel and other ferromagnetic materials for their magnetic characteristics such as permeability, remanent induction, coercive force and saturation induction. The present range of operation for the permeameter is from 0.5 Oe to 1250 Oe. Results are presented for two samples of low-carbon steel as well as some preliminary results for Vanadium Permendur. 4 refs., 8 figs.

  12. Design of a semi-custom integrated circuit for the SLAC SLC timing control system

    SciTech Connect

    Linstadt, E.

    1984-10-01

    A semi-custom (gate array) integrated circuit has been designed for use in the SLAC Linear Collider timing and control system. The design process and SLAC's experiences during the phases of the design cycle are described. Issues concerning the partitioning of the design into semi-custom and standard components are discussed. Functional descriptions of the semi-custom integrated circuit and the timing module in which it is used are given.

  13. Experimental Tests of the GDH and Other Sum Rules at SLAC

    SciTech Connect

    Bosted, P.E.; /Massachusetts U., Amherst

    2005-06-14

    Recent measurements from SLAC of the polarized nucleon structure functions g{sub 1} and g{sub 2} have been used to experimentally test the Bjorken, Ellis-Jaffe, Burkhardt-Cottingham, and Efremov-Leader-Teryaev sum rules. In the future, the SLAC E159 experiment will extend structure function measurements using real photons to 40 GeV, enabling a definitive test of the high energy convergence of the GDH sum rule for both proton and deuteron targets.

  14. Tests of an environmental and personnel safe cleaning process for Brookhaven National Laboratory accelerator and storage ring components

    SciTech Connect

    Foerster, C.L.; Lanni, C.; Lee, R.; Mitchell, G.; Quade, W.

    1997-05-01

    A large measure of the successful operation of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (BNL) for over a decade can be attributed to the cleaning of its ultrahigh vacuum (UHV) components during and after construction. A new UHV cleaning process, which has to be environmentally and personnel safe, is needed to replace the harsh, unfriendly process which is still in use. Dow Advanced Cleaning Systems was contracted to develop a replacement process without the use of harsh chemicals and which must clean vacuum surfaces as well as the existing process. Acceptance of the replacement process was primarily based on photon stimulated desorption (PSD) measurements of beam tube samples run on NSLS beam line U10B. One meter long beam tube samples were fabricated from aluminum, 304 stainless steel, and oxygen-free copper. Initially, coupon samples were cleaned and passed preliminary testing for the proposed process. Next, beam tube samples of each material were cleaned, and the PSD measured on beam line U10B using white light with a critical energy of 487 eV. Prior to cleaning, the samples were contaminated with a mixture of cutting oils, lubricants, vacuum oils, and vacuum grease. The contaminated samples were then baked. Samples of each material were also cleaned with the existing process after the same preparation. Beam tube samples were exposed to between 10{sup 22} and 10{sup 23} photons per meter for a PSD measurement. Desorption yields for H{sub 2}, CO, CO{sub 2}, CH{sub 4}, and H{sub 2}O are reported for both the existing cleaning and for the replacement cleaning process. Preliminary data, residual gas scans, and PSD results are given and discussed. The new process is also compared with new cleaning methods developed in other laboratories. After modification, the new UHV cleaning process was accepted by BNL.

  15. Investigation of the effects of acid rain on the deterioration of cement concrete using accelerated tests established in laboratory

    NASA Astrophysics Data System (ADS)

    Xie, Shaodong; Qi, Li; Zhou, Ding

    Deterioration of cement concrete specimens caused by simulated acid rain was investigated by laboratory tests. Before and after cement concrete specimens were exposed to simulated acid rain, the neutralized depth, the compressive strength and the chemical compositions in the hardened cement paste were measured. The mineralogical composition of the concrete specimens was analyzed with XRD. The results lead to the following conclusions: the neutralized depth of the concrete specimens of all experiments can be described as a power function of exposure duration, CaO loss and the reduction rate of strength increased with H + and decreased with SO 42- concentration in simulated acid rain. The original mineral compounds such as [Na K]AlSi 3O 8 and [Ca Na][SiAl] 4O 8 in the hardened cement paste are converted to CaSO 4·2H 2O, CaAl 2Si 2O 8 and Ca 3Al 6O 12·CaSO 4. And these are larger in volume so that the reaction with SO 42- ions result in volume expansion and strength decrease. The reduction rate of strength has a binary linear relation to the CaO loss rate and the ratio of SO 3 content to CaO content in the hardened cement paste. So the deterioration of acid rain on the concrete specimen is caused by both H + dissolution and SO 42- expansion.

  16. Engineered and Administrative Safety Systems for the Control of Prompt Radiation Hazards at Accelerator Facilities

    SciTech Connect

    Liu, James C.; Vylet, Vashek; Walker, Lawrence S.; /SLAC

    2007-12-17

    The ANSI N43.1 Standard, currently in revision (ANSI 2007), sets forth the requirements for accelerator facilities to provide adequate protection for the workers, the public and the environment from the hazards of ionizing radiation produced during and from accelerator operations. The Standard also recommends good practices that, when followed, provide a level of radiation protection consistent with those established for the accelerator communities. The N43.1 Standard is suitable for all accelerator facilities (using electron, positron, proton, or ion particle beams) capable of producing radiation, subject to federal or state regulations. The requirements (see word 'shall') and recommended practices (see word 'should') are prescribed in a graded approach that are commensurate with the complexity and hazard levels of the accelerator facility. Chapters 4, 5 and 6 of the N43.1 Standard address specially the Radiation Safety System (RSS), both engineered and administrative systems, to mitigate and control the prompt radiation hazards from accelerator operations. The RSS includes the Access Control System (ACS) and Radiation Control System (RCS). The main requirements and recommendations of the N43.1 Standard regarding the management, technical and operational aspects of the RSS are described and condensed in this report. Clearly some aspects of the RSS policies and practices at different facilities may differ in order to meet the practical needs for field implementation. A previous report (Liu et al. 2001a), which reviews and summarizes the RSS at five North American high-energy accelerator facilities, as well as the RSS references for the 5 labs (Drozdoff 2001; Gallegos 1996; Ipe and Liu 1992; Liu 1999; Liu 2001b; Rokni 1996; TJNAF 1994; Yotam et al. 1991), can be consulted for the actual RSS implementation at various laboratories. A comprehensive report describing the RSS at the Stanford Linear Accelerator Center (SLAC 2006) can also serve as a reference.

  17. High Gradient Accelerator Cavities Using Atomic Layer Deposition

    SciTech Connect

    Ives, Robert Lawrence; Parsons, Gregory; Williams, Philip; Oldham, Christopher; Mundy, Zach; Dolgashev, Valery

    2014-12-09

    In the Phase I program, Calabazas Creek Research, Inc. (CCR), in collaboration with North Carolina State University (NCSU), fabricated copper accelerator cavities and used Atomic Layer Deposition (ALD) to apply thin metal coatings of tungsten and platinum. It was hypothesized that a tungsten coating would provide a robust surface more resistant to arcing and arc damage. The platinum coating was predicted to reduce processing time by inhibiting oxides that form on copper surfaces soon after machining. Two sets of cavity parts were fabricated. One was coated with 35 nm of tungsten, and the other with approximately 10 nm of platinum. Only the platinum cavity parts could be high power tested during the Phase I program due to schedule and funding constraints. The platinum coated cavity exhibit poor performance when compared with pure copper cavities. Not only did arcing occur at lower power levels, but the processing time was actually longer. There were several issues that contributed to the poor performance. First, machining of the base copper cavity parts failed to achieve the quality and cleanliness standards specified to SLAC National Accelerator Center. Secondly, the ALD facilities were not configured to provide the high levels of cleanliness required. Finally, the nanometer coating applied was likely far too thin to provide the performance required. The coating was ablated or peeled from the surface in regions of high fields. It was concluded that the current ALD process could not provide improved performance over cavities produced at national laboratories using dedicated facilities.

  18. Functional analysis of Slac2-c/MyRIP as a linker protein between melanosomes and myosin VIIa.

    PubMed

    Kuroda, Taruho S; Fukuda, Mitsunori

    2005-07-29

    Slac2-c/MyRIP, an in vitro Rab27A- and myosin Va/VIIa-binding protein, has recently been proposed to regulate retinal melanosome transport in retinal pigment epithelium cells by directly linking melanosome-bound Rab27A and myosin VIIa; however, the exact function of Slac2-c in melanosome transport has never been clarified. In this study, we used melanosome transport in skin melanocytes as a model for retinal melanosome transport and analyzed the in vivo function of Slac2-c in melanosome transport by the ectopic expression of Slac2-c, together with myosin VIIa, in Slac2-a-depleted melanocytes. In vitro binding experiments revealed that myosin VIIa had a greater affinity for Slac2-c, compared with the binding affinity of myosin Va, and that the myosin VIIa-binding domain of Slac2-c is different from the previously characterized myosin Va-binding domain that is conserved between Slac2-a/melanophilin and Slac2-c. Consistent with this result, cyan fluorescent protein-tagged Slac2-c expressed in melanocytes was localized on melanosomes via the specific interaction with Rab27A and recruited co-expressed yellow fluorescent protein-tagged myosin VIIa to the melanosomes without interfering with the normal peripheral melanosome distribution, whereas when myosin VIIa alone was expressed in melanocytes, it was not localized on the melanosomes. Moreover, Slac2-c ectopically expressed in melanocytes did not rescue the perinuclear aggregation phenotype induced by the knockdown of endogenous Slac2-a with a specific small interfering RNA, whereas the expression of the Slac2-c x myosin VIIa complex supported the normal melanosome distribution in Slac2-a-depleted melanocytes, indicating that Slac2-c functions as a myosin VIIa receptor rather than a myosin Va receptor in melanosome transport. Based on these findings, we propose that Slac2-c acts as a functional myosin VIIa receptor and that the Rab27A.Slac2-c x myosin VIIa tripartite protein complex regulates the transport of retinal

  19. 2D and 3D multipactor modeling in dielectric-loaded accelerator structures

    NASA Astrophysics Data System (ADS)

    Sinitsyn, Oleksandr; Nusinovich, Gregory; Antonsen, Thomas

    2010-11-01

    Multipactor (MP) is known as the avalanche growth of the number of secondary electrons emitted from a solid surface exposed to an RF electric field under vacuum conditions. MP is a severe problem in modern rf systems and, therefore, theoretical and experimental studies of MP are of great interest to the researchers working in various areas of physics and engineering. In this work we present results of MP studies in dielectric-loaded accelerator (DLA) structures. First, we show simulation results obtained with the use of the 2D self-consistent MP model (O. V. Sinitsyn, et. al., Phys. Plasmas, vol. 16, 073102 (2009)) and compare those to experimental ones obtained during recent extensive studies of DLA structures performed by Argonne National Laboratory, Naval Research Laboratory, SLAC National Accelerator Laboratory and Euclid TechLabs (C. Jing, et al., IEEE Trans. Plasma Sci., vol. 38, pp. 1354-1360 (2010)). Then we present some new results of 3D analysis of MP which include studies of particle trajectories and studies of MP development at the early stage.

  20. Accelerating the Whiteshell Laboratories Decommissioning Through the Implementation of a Projectized and Delivery-Focused Organization - 13074

    SciTech Connect

    Wilcox, Brian; Mellor, Russ; Michaluk, Craig

    2013-07-01

    Whiteshell Laboratories (WL) is a nuclear research site in Canada that was commissioned in 1964 by Atomic Energy of Canada Limited. It covers a total area of approximately 4,375 hectares (10,800 acres) and includes the main campus site, the Waste Management Area (WMA) and outer areas of land identified as not used for or impacted by nuclear development or operations. The WL site employed up to 1100 staff. Site activities included the successful operation of a 60 MW organic liquid-cooled research reactor from 1965 to 1985, and various research programs including reactor safety research, small reactor development, fuel development, biophysics and radiation applications, as well as work under the Canadian Nuclear Fuel Waste Management Program. In 1997, AECL made a business decision to discontinue research programs and operations at WL, and obtained government concurrence in 1998. The Nuclear Legacy Liabilities Program (NLLP) was established in 2006 by the Canadian Government to remediate nuclear legacy liabilities in a safe and cost effective manner, including the WL site. The NLLP is being implemented by AECL under the governance of a Natural Resources Canada (NRCan)/AECL Joint Oversight Committee (JOC). Significant progress has since been made, and the WL site currently holds the only Canadian Nuclear Safety Commission (CNSC) nuclear research site decommissioning license in Canada. The current decommissioning license is in place until the end of 2018. The present schedule planned for main campus decommissioning is 30 years (to 2037), followed by institutional control of the WMA until a National plan is implemented for the long-term management of nuclear waste. There is an impetus to advance work and complete decommissioning sooner. To accomplish this, AECL has added significant resources, reorganized and moved to a projectized environment. This presentation outlines changes made to the organization, the tools implemented to foster projectization, and the benefits

  1. The Stanford Synchrotron Radiation Laboratory, 20 years of synchrotron light

    SciTech Connect

    Cantwell, K.

    1993-08-01

    The Stanford Synchrotron Radiation Laboratory (SSRL) is now operating as a fully dedicated light source with low emittance electron optics, delivering high brightness photon beams to 25 experimental stations six to seven months per year. On October 1, 1993 SSRL became a Division of the Stanford Linear Accelerator Center, rather than an Independent Laboratory of Stanford University, so that high energy physics and synchrotron radiation now function under a single DOE contract. The SSRL division of SLAC has responsibility for operating, maintaining and improving the SPEAR accelerator complex, which includes the storage ring and a 3 GeV injector. SSRL has thirteen x-ray stations and twelve VUV/Soft x-ray stations serving its 600 users. Recently opened to users is a new spherical grating monochromator (SGM) and a multiundulator beam line. Circularly polarized capabilities are being exploited on a second SGM line. New YB{sub 66} crystals installed in a vacuum double-crystal monochromator line have sparked new interest for Al and Mg edge studies. One of the most heavily subscribed stations is the rotation camera, which has been recently enhanced with a MAR imaging plate detector system for protein crystallography on a multipole wiggler. Under construction is a new wiggler-based structural molecular biology beam line with experimental stations for crystallography, small angle scattering and x-ray absorption spectroscopy. Plans for new developments include wiggler beam lines and associated facilities specialized for environmental research and materials processing.

  2. Calculation of Transactinide Homolog Isotope Production Reactions Possible with the Center for Accelerator Mass Spectrometry (CAMS) at Lawrence Livermore National Laboratory

    SciTech Connect

    Moody, K J; Shaughnessy, D A; Gostic, J M

    2011-11-29

    The LLNL heavy element group has been investigating the chemical properties of the heaviest elements over the past several years. The properties of the transactinides (elements with Z > 103) are often unknown due to their low production rates and short half-lives, which require lengthy cyclotron irradiations in order to make enough atoms for statistically significant evaluations of their chemistry. In addition, automated chemical methods are often required to perform consistent and rapid chemical separations on the order of minutes for the duration of the experiment, which can last from weeks to months. Separation methods can include extraction chromatography, liquid-liquid extraction, or gas-phase chromatography. Before a lengthy transactinide experiment can be performed at an accelerator, a large amount of preparatory work must be done both to ensure the successful application of the chosen chemical system to the transactinide chemistry problem being addressed, and to evaluate the behavior of the lighter elemental homologs in the same chemical system. Since transactinide chemistry is literally performed on one single atom, its chemical properties cannot be determined from bulk chemical matrices, but instead must be inferred from the behavior of the lighter elements that occur in its chemical group and in those of its neighboring elements. By first studying the lighter group homologs in a particular chemical system, when the same system is applied to the transactinide element under investigation, its decay properties can be directly compared to those of the homologues, thereby allowing an inference of its own chemistry. The Center for Accelerator Mass Spectrometry (CAMS) at Lawrence Livermore National Laboratory (LLNL) includes a 1 MV Tandem accelerator, capable of accelerating light ions such as protons to energies of roughly 15 MeV. By using the CAMS beamline, tracers of transactinide homolog elements can be produced both for development of chemical systems and

  3. Accelerator mass spectrometry of 63Ni at the Munich Tandem Laboratory for estimating fast neutron fluences from the Hiroshima atomic bomb.

    PubMed

    Rühm, W; Knie, K; Rugel, G; Marchetti, A A; Faestermann, T; Wallner, C; McAninch, J E; Straume, T; Korschinek, G

    2000-10-01

    After the release of the present dosimetry system DS86 in 1987, measurements have shown that DS86 may substantially underestimate thermal neutron fluences at large distances (>1,000 m) from the hypocenter in Hiroshima. This discrepancy casts doubts on the DS86 neutron source term and, consequently, the survivors' estimated neutron doses. However, the doses were caused mainly by fast neutrons. To determine retrospectively fast neutron fluences in Hiroshima, the reaction 63Cu(n, p)63Ni can be used, if adequate copper samples can be found. Measuring 63Ni (half life 100 y) in Hiroshima samples requires a very sensitive technique, such as accelerator mass spectrometry (AMS), because of the relatively small amounts of 63Ni expected (approximately 10(5)-10(6) atoms per gram of copper). Experiments performed at Lawrence Livermore National Laboratory have demonstrated in 1996 that AMS can be used to measure 63Ni in Hiroshima copper samples. Subsequently, a collaboration was established with the Technical University of Munich in view of its potential to perform more sensitive measurements of 63Ni than the Livermore facility and in the interest of interlaboratory validation. This paper presents the progress made at the Munich facility in the measurement of 63Ni by AMS. The Munich accelerator mass spectrometry facility is a combination of a high energy tandem accelerator and a detection system featuring a gas-filled magnet. It is designed for high sensitivity measurements of long-lived radioisotopes. Optimization of the ion source setup has further improved the sensitivity for 63Ni by reducing the background level of the 63Cu isobar interference by about two orders of magnitude. Current background levels correspond to a ratio of 63Ni/Ni<2x10(-14) and suggest that, with adequate copper samples, the assessment of fast neutron fluences in Hiroshima and Nagasaki is possible for ground distances of up to 1500 m, and--under favorable conditions--even beyond. To demonstrate this

  4. SLAC modulator availability and impact on SLC operation

    SciTech Connect

    Donaldson, A.R.; Ashton, J.R.

    1995-05-01

    In 1991, the Stanford Linear Collider (SLC) operated, with diverse accelerator systems, at 60% availability. In the more auspicious 1992 and 1993 runs availability improved to over 80%. For the 94/95 run, the availability was also about 80%. Ignoring the eclectic-accelerator, this discussion will assess the dependence of the SLC on the reliability and hence, availability, of 244 klystron modulator systems that provide power to the machine`s bunched-particle beams. Klystron modulator availability must be 99% for the accelerator to function at the 75% level. Fortunately, an excess of modulator/klystrons provides some redundancy and, therefore, allows some freedom from the requirement that all 244 systems perform simultaneously. There are, however, 15 specific exceptions. They populate strategic positions at the injector, damping rings, and positron production area of the accelerator complex. These, systems-without-spares, directly influence overall accelerator availability. Their calculated availability as an ensemble is 90%, but by chance they have operated at up to 99%. Individually, a malfunction can bring an experimental program to a halt. The discussion includes a description of several improvements to increase future availability for the modulator system.

  5. Mass decomposition of SLACS lens galaxies in Weyl conformal gravity

    NASA Astrophysics Data System (ADS)

    Potapov, Alexander A.; Izmailov, Ramil N.; Nandi, Kamal K.

    2016-06-01

    We study here, using the Mannheim-Kazanas solution of Weyl conformal theory, the mass decomposition in the representative subsample of 57 early-type elliptical lens galaxies of the Sloan Lens Advanced Camera for Surveys (SLACS) on board the Hubble Space Telescope. We begin by showing that the solution need not be an exclusive solution of conformal gravity but can also be viewed as a solution of a class of f (R ) gravity theories coupled to nonlinear electrodynamics thereby rendering the ensuing results more universal. Since lensing involves light bending, we shall first show that the solution adds to Schwarzschild light bending caused by the luminous mass (M*) a positive contribution +γ R contrary to the previous results in the literature, thereby resolving a long-standing problem. The cause of the error is critically examined. Next, applying the expressions for light bending together with an input equating Einstein and Weyl angles, we develop a novel algorithm for separating the luminous component from the total lens mass (luminous+dark ) within the Einstein radius. Our results indicate that the luminous mass estimates differ from the observed total lens masses by a linear proportionality factor across the subsample, which qualitatively agrees with the common conclusion from a number of different simulations in the literature. In quantitative detail, we observe that the ratios of luminous over total lens mass (f*) within the Einstein radius of individual galaxies take on values near unity, many of which remarkably fall inside or just marginally outside the specified error bars obtained from a simulation based on the Bruzual-Charlot stellar population synthesis model together with the Salpeter initial mass function favored on the ground of metallicity [Grillo et al., Astron. Astrophys. 501, 461 (2009)]. We shall also calculate the average dark matter density ⟨ρ⟩ av of individual galaxies within their respective Einstein spheres. To our knowledge, the present

  6. Basic concepts in plasma accelerators.

    PubMed

    Bingham, Robert

    2006-03-15

    In this article, we present the underlying physics and the present status of high gradient and high-energy plasma accelerators. With the development of compact short pulse high-brightness lasers and electron and positron beams, new areas of studies for laser/particle beam-matter interactions is opening up. A number of methods are being pursued vigorously to achieve ultra-high-acceleration gradients. These include the plasma beat wave accelerator (PBWA) mechanism which uses conventional long pulse ( approximately 100 ps) modest intensity lasers (I approximately 10(14)-10(16) W cm(-2)), the laser wakefield accelerator (LWFA) which uses the new breed of compact high-brightness lasers (<1 ps) and intensities >10(18) W cm(-2), self-modulated laser wakefield accelerator (SMLWFA) concept which combines elements of stimulated Raman forward scattering (SRFS) and electron acceleration by nonlinear plasma waves excited by relativistic electron and positron bunches the plasma wakefield accelerator. In the ultra-high intensity regime, laser/particle beam-plasma interactions are highly nonlinear and relativistic, leading to new phenomenon such as the plasma wakefield excitation for particle acceleration, relativistic self-focusing and guiding of laser beams, high-harmonic generation, acceleration of electrons, positrons, protons and photons. Fields greater than 1 GV cm(-1) have been generated with monoenergetic particle beams accelerated to about 100 MeV in millimetre distances recorded. Plasma wakefields driven by both electron and positron beams at the Stanford linear accelerator centre (SLAC) facility have accelerated the tail of the beams. PMID:16483948

  7. Design study for a hard X-ray source with a femto-second length by using Compton scattering at the Pohang Accelerator Laboratory

    NASA Astrophysics Data System (ADS)

    Kim, Eun-San; Kim, KyungRyul

    2016-02-01

    X-ray generation based on laser-electron Compton scattering is a method to generate a compact high-flux X-ray source. At the Pohang Accelerator Laboratory's (PAL's) fs-THz facility, 3-THz radiation has been achieved using an electron beam of 150 fs rms. To further enhance the radiation bandwidth, we present design results on X-ray generation by using Compton scattering at the facility. We show the design performance for the Compton source by using a 75-MeV electron linac with a 800-nm laser system. The Compton scattering X-ray source will be a compact facility that produces 3.1 × 107 photons in a single shot and a maximum photon energy of 130 keV. In this paper, we show the system layout and the design parameters that offers an ultra-short, high-flux hard X-ray source. We present the simulation studies to optimize the parameters of the electron beam and the X-ray pulse that was given by code CAIN.

  8. Initial Testing of the Mark-0 X-Band RF Gun at SLAC

    SciTech Connect

    Vlieks, Arnold; Adolphsen, C.; Dolgashev, V.; Lewandowski, J.; Limborg, Cecile; Weathersby, S.; /SLAC

    2012-06-06

    A new X-band RF gun (Mark-0) has been assembled, tuned and was tested in the ASTA facility at SLAC. This gun has been improved from an earlier gun used in Compton-scattering experiments at SLAC by the introduction of a racetrack dual-input coupler to reduce quadrupole fields. Waveguide-to-coupler irises were also redesigned to reduce surface magnetic fields and therefore peak pulse surface heating. Tests of this photocathode gun will allow us to gain early operational experience for beam tests of a new gun with further improvements (Mark-1) being prepared for SLAC's X-Band Test Area (XTA) program and the LLNL MEGa-ray program. Results of current testing up to {approx} 200 MV/m peak surface Electric fields are presented.

  9. Laser-and Beam-Driven Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Joshi, Chandrashekhar

    2006-10-01

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

  10. Electroweak Radiative Corrections to the Parity-violating Asymmetry for SLAC Experiment E158

    SciTech Connect

    Zykunov, Vladimir A.; /Gomel State Tech. U.

    2012-04-04

    Electroweak radiative corrections to observable quantities of Moeller scattering of polarized particles are calculated. We emphasize the contribution induced by infrared divergent parts of cross section. The covariant method is used to remove infrared divergences, so that our results do not involve any unphysical parameters. When applied to the kinematics of SLAC E158 experiment, these corrections reduce the parity violating asymmetry by about -6.5% at E = 48 GeV and y = 0.5, and kinematically weighted 'hard' bremsstrahlung effect for SLAC E158 is {approx} 1%.

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

    SciTech Connect

    Byer, Robert L.

    2013-11-07

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

  12. Ion Acceleration by Laser Plasma Interaction from Cryogenic Micro Jets - Oral Presentation

    SciTech Connect

    Propp, Adrienne

    2015-08-25

    Processes that occur in extreme conditions, such as in the center of stars and large planets, can be simulated in the laboratory using facilities such as SLAC National Accelerator Laboratory and the Jupiter Laser Facility (JLF) at Lawrence Livermore National Laboratory (LLNL). These facilities allow scientists to investigate the properties of matter by observing their interactions with high power lasers. Ion acceleration from laser plasma interaction is gaining greater attention today due to its widespread potential applications, including proton beam cancer therapy and fast ignition for energy production. Typically, ion acceleration is achieved by focusing a high power laser on thin foil targets through a mechanism called Target Normal Sheath Acceleration. Based on research and recent experiments, we hypothesized that a pure liquid cryogenic jet would be an ideal target for this type of interaction, capable of producing the highest proton energies possible with today’s laser technologies. Furthermore, it would provide a continuous, pure target, unlike metal foils which are consumed in the interaction and easily contaminated. In an effort to test this hypothesis and investigate new, potentially more efficient mechanisms of ion acceleration, we used the 527 nm split beam, frequency-doubled TITAN laser at JLF. Data from the cryogenic jets was limited due to the flow of current up the jet into the nozzle during the interaction, heating the jet and damaging the orifice. However, we acheived a pure proton beam with an indiciation of a monoenergetic feature. Furthermore, data from gold and carbon wires showed surprising and interesting results. Preliminary analysis of data from two ion emission diagnostics, Thomson parabola spectrometers (TPs) and radio chromic films (RCFs), suggests that shockwave acceleration occurred rather than target normal sheath acceleration, the standard mechanism of ion acceleration. Upon completion of the experiment at TITAN, I researched the

  13. Elementary principles of linear accelerators

    SciTech Connect

    Loew, G.A.; Talman, R.

    1983-09-01

    These lectures come in five sections. The first is this introduction. The second is a short chronology of what are viewed as important milestones in the field. The third covers proton linacs. It introduces elementary concepts such as transit time, shunt impedance, and Q. Critical issues such as phase stability and transverse forces are discussed. The fourth section contains an elementary discussion of waveguide accelerating structures. It can be regarded as an introduction to some of the more advanced treatments of the subject. The final section is devoted to electron accelerators. Taking SLAC as an example, various topics are discussed such as structure design, choice of parameters, frequency optimization, beam current, emittance, bunch length and beam loading. Recent developments and future challenges are mentioned briefly. 41 figures, 4 tables.

  14. Optimization and validation of an accelerated laboratory extraction method to estimate nitrogen release patterns of slow- and controlled-release fertilizers.

    PubMed

    Medina, L Carolina; Sartain, Jerry B; Obreza, Thomas A; Hall, William L; Thiex, Nancy J

    2014-01-01

    Several technologies have been proposed to characterize the nutrient release and availability patterns of enhanced-efficiency fertilizers (EEFs), especially slow-release fertilizers (SRFs) and controlled-release fertilizers (CRFs) during the last few decades. These technologies have been developed mainly by manufacturers and are product-specific based on the regulation and analysis of each EEF product. Despite previous efforts to characterize EEF materials, no validated method exists to assess their nutrient release patterns. However, the increased use of EEFs in specialty and nonspecialty markets requires an appropriate method to verify nutrient claims and material performance. A series of experiments were conducted to evaluate the effect of temperature, fertilizer test portion size, and extraction time on the performance of a 74 h accelerated laboratory extraction method to measure SRF and CRF nutrient release profiles. Temperature was the only factor that influenced nutrient release rate, with a highly marked effect for phosphorus and to a lesser extent for nitrogen (N) and potassium. Based on the results, the optimal extraction temperature set was: Extraction No. 1-2:00 h at 25 degrees C; Extraction No. 2-2:00 h at 50 degrees C; Extraction No. 3-20:00 h at 55 degrees C; and Extraction No. 4-50:00 h at 60 degrees C. Ruggedness of the method was tested by evaluating the effect of small changes in seven selected factors on method behavior using a fractional multifactorial design. Overall, the method showed ruggedness for measuring N release rates of coated CRFs. PMID:25051611

  15. US Particle Accelerators at Age 50.

    ERIC Educational Resources Information Center

    Wilson, R. R.

    1981-01-01

    Reviews the development of accelerators over the past 50 years. Topics include: types of accelerators, including cyclotrons; sociology of accelerators (motivation, financing, construction, and use); impact of war; national laboratories; funding; applications; future projects; foreign projects; and international collaborations. (JN)

  16. dE/dx electronics for MARK II experiment at SLAC

    SciTech Connect

    Bernstein, D.; Boyarski, A.; Coupal, D.; Feldman, G.; Paffrath, L.

    1985-10-01

    This paper describes a 100 MHz pulse digitizer for dE/dx measurements on the MARK II drift chamber at SLAC. The electronics provides the read-out of the detector's 5832 sense based on a 16-channel FASTBUS module. The basic element of the module is the TRW 6-bit Flash-ADC.

  17. Coil-winding fixture for SLAC's Mark III detector (Engineering Materials)

    SciTech Connect

    Not Available

    1980-01-01

    The two drawings listed provide the construction information for the modification to a previously-used coil form. The second drawing provides the information for construction of the form's drive sprocket. This basic form and drive mechanism with appropriate modifications was used to wind coils for the Mark II, Mark III and TPC experiment magnets as used at SLAC.

  18. A user's guide to particle physics computer-searchable databases on the SLAC-SPIRES system

    SciTech Connect

    Rittenberg, A.; Armstrong, F.E.; Levine, B.S.; Trippe, T.G.; Wohl, C.G.; Yost, G.P.; Whalley, M.R.; Addis, L.

    1986-09-01

    This report discusses five computer-searchable databases located at SLAC which are of interest to particle physicists. These databases assist the user in literature-searching, provide numerical data extracted from papers, and contain information about experiments. We describe the databases briefly, tell how to use the SPIRES database management system to access them interactively, and give several examples of their use.

  19. Final report for the 1996 DOE grant supporting research at the SLAC/LBNL/LLNL B factory

    SciTech Connect

    Judd, D.; Wright, D.

    1997-08-08

    This final report discusses Department of Energy-supported research funded through Lawrence Livermore National Laboratory (LLNL) which was performed as part of a collaboration between LLNL and Prairie View A and M University to develop part of the BaBar detector at the SLAC B Factory. This work focuses on the Instrumented Flux Return (IFR) subsystem of BaBar and involves a full range of detector development activities: computer simulations of detector performance, creation of reconstruction algorithms, and detector hardware R and D. Lawrence Livermore National Laboratory has a leading role in the IFR subsystem and has established on-site computing and detector facilities to conduct this research. By establishing ties with the existing LLNL Research Collaboration Program and leveraging LLNL resources, the experienced Prairie View group was able to quickly achieve a more prominent role within the BaBar collaboration and make significant contributions to the detector design. In addition, this work provided the first entry point for Historically Black Colleges and Universities into the B Factory collaboration, and created an opportunity to train a new generation of minority students at the premier electron-positron high energy physics facility in the US.

  20. Design of the detuned accelerator structure

    SciTech Connect

    Wang, J.W.; Nelson, E.M.

    1993-05-01

    This is a summary of the design procedure for the detuned accelerator structure for SLAC`s Next Linear Collider (NLC) program. The 11.424 GHz accelerating mode of each cavity must be synchronous with the beam. The distribution of the disk thicknesses and lowest synchronous dipole mode frequencies of the cavities in the structure is Gaussian in order to reduce the effect of wake fields. The finite element field solver YAP calculated the accelerating mode frequency and the lowest synchronous dipole mode frequency for various cavity diameters, aperture diameters and disk thicknesses. Polynomial 3-parameter fits are used to calculate the dimensions for a 1.8 m detuned structure. The program SUPERFISH was used to calculate the shunt impedances, quality factors and group velocities. The RF parameters of the section like filling time, attenuation factor, accelerating gradient and maximum surface field along the section are evaluated. Error estimates will be discussed and comparisons with conventional constant gradient and constant impedance structures will be presented.

  1. Molecular Evolution of Slow and Quick Anion Channels (SLACs and QUACs/ALMTs)

    PubMed Central

    Dreyer, Ingo; Gomez-Porras, Judith Lucia; Riaño-Pachón, Diego Mauricio; Hedrich, Rainer; Geiger, Dietmar

    2012-01-01

    Electrophysiological analyses conducted about 25 years ago detected two types of anion channels in the plasma membrane of guard cells. One type of channel responds slowly to changes in membrane voltage while the other responds quickly. Consequently, they were named SLAC, for SLow Anion Channel, and QUAC, for QUick Anion Channel. Recently, genes SLAC1 and QUAC1/ALMT12, underlying the two different anion current components, could be identified in the model plant Arabidopsis thaliana. Expression of the gene products in Xenopus oocytes confirmed the quick and slow current kinetics. In this study we provide an overview on our current knowledge on slow and quick anion channels in plants and analyze the molecular evolution of ALMT/QUAC-like and SLAC-like channels. We discovered fingerprints that allow screening databases for these channel types and were able to identify 192 (177 non-redundant) SLAC-like and 422 (402 non-redundant) ALMT/QUAC-like proteins in the fully sequenced genomes of 32 plant species. Phylogenetic analyses provided new insights into the molecular evolution of these channel types. We also combined sequence alignment and clustering with predictions of protein features, leading to the identification of known conserved phosphorylation sites in SLAC1-like channels along with potential sites that have not been yet experimentally confirmed. Using a similar strategy to analyze the hydropathicity of ALMT/QUAC-like channels, we propose a modified topology with additional transmembrane regions that integrates structure and function of these membrane proteins. Our results suggest that cross-referencing phylogenetic analyses with position-specific protein properties and functional data could be a very powerful tool for genome research approaches in general. PMID:23226151

  2. Plasma Dark Current in Self-Ionized Plasma Wakefield Accelerators

    SciTech Connect

    Oz, E.; Deng, S.; Katsouleas, T.; Muggli, P.; Iverson, R.; Johnson, D.K.; Krejcik, P.; O'Connell, C.; Siemann, R.H.; Walz, D.; Clayton, C.E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; /UCLA

    2006-01-30

    Evidence of particle trapping has been observed in a beam driven Plasma Wake Field Accelerator (PWFA) experiment, E164X, conducted at the Stanford Linear Accelerator Center by a collaboration which includes USC, UCLA and SLAC. Such trapping produces plasma dark current when the wakefield amplitude is above a threshold value and may place a limit on the maximum acceleration gradient in a PWFA. Trapping and dark current are enhanced when in an ionizing plasma, that is self-ionized by the beam. Here we present experimental results.

  3. Linear Accelerators

    NASA Astrophysics Data System (ADS)

    Sidorin, Anatoly

    2010-01-01

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  4. Linear Accelerators

    SciTech Connect

    Sidorin, Anatoly

    2010-01-05

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  5. Measurement of the Decelerating Wake in a Plasma Wakefield Accelerator

    SciTech Connect

    Blumenfeld, I.; Decker, F. J.; Hogan, M. J.; Ischebeck, R.; Iverson, R. H.; Kirby, N.; Siemann, R. H.; Walz, D. R.; Clayton, C. E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K. A.; Mori, W. B.; Zhou, M.; Katsouleas, T.; Muggli, P.; Oz, E.

    2009-01-22

    Recent experiments at SLAC have shown that high gradient acceleration of electrons is achievable in meter scale plasmas. Results from these experiments show that the wakefield is sensitive to parameters in the electron beam which drives it. In the experiment the bunch lengths were varied systematically at constant charge. The effort to extract a measurement of the decelerating wake from the maximum energy loss of the electron beam is discussed.

  6. Energy Measurements of Trapped Electrons from a Plasma Wakefield Accelerator

    SciTech Connect

    Kirby, Neal; Auerbach, David; Berry, Melissa; Blumenfeld, Ian; Clayton, Christopher E.; Decer, Franz-Josef; Hogan, Mark J.; Huang, Chengkun; Ischebeck, Rasmus; Iverson, Richard; Johnson, Devon; Joshi, Chadrashekhar; Katsouleas, Thomas; Lu, Wei; Marsh, Kenneth A.; Mori, Warren B.; Muggli, Patric; Oz, Erdem; Siemann, Robert H.; Walz, Dieter; Zhou, Miaomiao; /SLAC /UCLA /Southern California U.

    2007-01-03

    Recent electron beam driven plasma wakefield accelerator experiments carried out at SLAC indicate trapping of plasma electrons. More charge came out of than went into the plasma. Most of this extra charge had energies at or below the 10 MeV level. In addition, there were trapped electron streaks that extended from a few GeV to tens of GeV, and there were mono-energetic trapped electron bunches with tens of GeV in energy.

  7. Experimental Results from a Resonant Dielectric Laser Accelerator

    NASA Astrophysics Data System (ADS)

    Yoder, Rodney; McNeur, Joshua; Sozer, Esin; Travish, Gil; Hazra, Kiran Shankar; Matthews, Brian; England, Joel; Peralta, Edgar; Wu, Ziran

    2015-04-01

    Laser-powered accelerators have the potential to operate with very large accelerating gradients (~ GV/m) and represent a path toward extremely compact colliders and accelerator technology. Optical-scale laser-powered devices based on field-shaping structures (known as dielectric laser accelerators, or DLAs) have been described and demonstrated recently. Here we report on the first experimental results from the Micro-Accelerator Platform (MAP), a DLA based on a slab-symmetric resonant optical-scale structure. As a resonant (rather than near-field) device, the MAP is distinct from other DLAs. Its cavity resonance enhances its accelerating field relative to the incoming laser fields, which are coupled efficiently through a diffractive optic on the upper face of the device. The MAP demonstrated modest accelerating gradients in recent experiments, in which it was powered by a Ti:Sapphire laser well below its breakdown limit. More detailed results and some implications for future developments will be discussed. Supported in part by the U.S. Defense Threat Reduction Agency (UCLA); U.S. Dept of Energy (SLAC); and DARPA (SLAC).

  8. PARTICLE ACCELERATOR

    DOEpatents

    Teng, L.C.

    1960-01-19

    ABS>A combination of two accelerators, a cyclotron and a ring-shaped accelerator which has a portion disposed tangentially to the cyclotron, is described. Means are provided to transfer particles from the cyclotron to the ring accelerator including a magnetic deflector within the cyclotron, a magnetic shield between the ring accelerator and the cyclotron, and a magnetic inflector within the ring accelerator.

  9. Direct measurements of Ab and Ac using vertex and kaon charge tags at the SLAC detector.

    PubMed

    Abe, Koya; Abe, Kenji; Abe, T; Adam, I; Akimoto, H; Aston, D; Baird, K G; Baltay, C; Band, H R; Barklow, T L; Bauer, J M; Bellodi, G; Berger, R; Blaylock, G; Bogart, J R; Bower, G R; Brau, J E; Breidenbach, M; Bugg, W M; Burke, D; Burnett, T H; Burrows, P N; Calcaterra, A; Cassell, R; Chou, A; Cohn, H O; Coller, J A; Convery, M R; Cook, V; Cowan, R F; Crawford, G; Damerell, C J S; Daoudi, M; Dasu, S; de Groot, N; de Sangro, R; Dong, D N; Doser, M; Dubois, R; Erofeeva, I; Eschenburg, V; Etzion, E; Fahey, S; Falciai, D; Fernandez, J P; Flood, K; Frey, R; Hart, E L; Hasuko, K; Hertzbach, S S; Huffer, M E; Huynh, X; Iwasaki, M; Jackson, D J; Jacques, P; Jaros, J A; Jiang, Z Y; Johnson, A S; Johnson, J R; Kajikawa, R; Kalelkar, M; Kang, H J; Kofler, R R; Kroeger, R S; Langston, M; Leith, D W G; Lia, V; Lin, C; Mancinelli, G; Manly, S; Mantovani, G; Markiewicz, T W; Maruyama, T; McKemey, A K; Messner, R; Moffeit, K C; Moore, T B; Morii, M; Muller, D; Murzin, V; Narita, S; Nauenberg, U; Neal, H; Nesom, G; Oishi, N; Onoprienko, D; Osborne, L S; Panvini, R S; Park, C H; Peruzzi, I; Piccolo, M; Piemontese, L; Plano, R J; Prepost, R; Prescott, C Y; Ratcliff, B N; Reidy, J; Reinertsen, P L; Rochester, L S; Rowson, P C; Russell, J J; Saxton, O H; Schalk, T; Schumm, B A; Schwiening, J; Serbo, V V; Shapiro, G; Sinev, N B; Snyder, J A; Staengle, H; Stahl, A; Stamer, P; Steiner, H; Su, D; Suekane, F; Sugiyama, A; Suzuki, A; Swartz, M; Taylor, F E; Thom, J; Torrence, E; Usher, T; Va'vra, J; Verdier, R; Wagner, D L; Waite, A P; Walston, S; Weidemann, A W; Weiss, E R; Whitaker, J S; Williams, S H; Willocq, S; Wilson, R J; Wisniewski, W J; Wittlin, J L; Woods, M; Wright, T R; Yamamoto, R K; Yashima, J; Yellin, S J; Young, C C; Yuta, H

    2005-03-11

    Exploiting the manipulation of the SLAC Linear Collider electron-beam polarization, we present precise direct measurements of the parity-violation parameters A(c) and A(b) in the Z-boson-c-quark and Z-boson-b-quark coupling. Quark-antiquark discrimination is accomplished via a unique algorithm that takes advantage of the precise SLAC Large Detector charge coupled device vertex detector, employing the net charge of displaced vertices as well as the charge of kaons that emanate from those vertices. From the 1996-1998 sample of 400 000 Z decays, produced with an average beam polarization of 73.4%, we find A(c)=0.673+/-0.029(stat)+/-0.023(syst) and A(b)=0.919+/-0.018(stat)+/-0.017(syst). PMID:15783953

  10. Longitudinal Wakefield Study in SLAC Rotatable Collimator Design for the LHC Phase II Upgrade

    SciTech Connect

    Xiao, Liling; Lundgren, Steven; Markiewicz, Thomas; Ng, Cho-Kuen; Smith, Jeffrey; /SLAC

    2010-08-25

    SLAC proposed a rotatable collimator design for the LHC Phase II collimation upgrade. There are 20 facet faces on each cylindrical jaw surface and two jaws are rotatable in order to introduce a clean surface in case of a beam hitting a jaw during operation. When the beam crosses the collimator, it will excite broad-band and narrow-band modes. The longitudinal modes can contribute to beam energy loss and power dissipation on the vacuum chamber wall. In this paper, the parallel finite element eigensolver Omega3P is used to search for all the longitudinal trapped modes in the SLAC collimator design. The power dissipation generated by the beam in collimators with different vacuum chamber and RF contact designs is discussed. It is found that a wider RF foil connecting the jaw and the vacuum flange can reduce efficiently the beam heating caused by the longitudinal modes.

  11. Final Report: BaBar Detector and Experimental at SLAC, September 30, 1998 - September 29, 1999

    SciTech Connect

    Judd, Dennis J.

    2000-01-20

    The Prairie View A&M University High Energy Physics Group with its contingent of three undergraduates physics majors, joined the BaBar Collaboration at SLAC in September 1994. BaBar is the experiment and detector running in the PEP-II ring at SLAC as part of the Asymmetric B Factory project there to study CP violation and heavy flavor physics. The focus of our effort before this year was with the Muon/Neutral Hadron Detector/Instrumented Flux Return (IFD) subgroup within the BaBar collaboration, and particularly with the GEANT simulation of the IFR. With the GEANT3 simulation essentially frozen, and the GEANT4 full simulation of the IFR done, we have decided to redirect our efforts toward other areas.

  12. Lattice design and optimization for the PEP-X ultra low emittance storage ring at SLAC

    SciTech Connect

    Wang, Min-Huey; Nosochkov, Yuri; Bane, Karl; Cai, Yunhai; Hettel, Robert; Huang, Xiaobiao; /SLAC

    2011-08-12

    SLAC is developing a long-range plan to transfer the evolving scientific programs at SSRL from the SPEAR3 light source to a much higher performing photon source. One of the possibilities is a new PEP-X 4.5 GeV storage ring that would be housed in the 2.2 km PEP-II tunnel. The PEP-X is designed to produce photon beams having brightness near 10{sup 22} (ph/s/mm{sup 2}/mrad{sup 2}/0.1% BW) at 10 keV with 3.5 m undulator at beam current of 1.5 A. This report presents an overview of the PEP-X baseline lattice design and describes the lattice optimization procedures in order to maximize the beam dynamic aperture. The complete report of PEP-X baseline design is published in SLAC report.

  13. High-brightness, high-energy radiation generation from non-linear Thomson scattering of laser wakefield accelerated electrons

    NASA Astrophysics Data System (ADS)

    Schumaker, W.; Zhao, Z.; Thomas, A. G. R.; Krushelnick, K.; Sarri, G.; Corvan, D.; Zepf, M.; Cole, J.; Mangles, S. P. D.; Najmudin, Z.

    2014-10-01

    To date, all-optical sources of high-energy (>MeV) photons have only been reported in the linear (a0 < 1) regime of Thomson scattering using laser wakefield acceleration (LWFA). We present novel results of high-brightness, high-energy photons generated via non-linear Thomson scattering using the two-beam Astra-Gemini laser facility. With one 300 TW beam, electrons were first accelerated to 500 MeV energies inside gas cells through the process of LWFA. A second 300 TW laser pulse focused to a0 = 2 was subsequently scattered off these electrons, resulting in a highly directional, small source size, and short pulse beam of photons with >10 MeV energies. The photon beam was propagated through a low- Z converter and produced Compton-scattered electrons that were spectrally measured by magnetic deflection and correlated with the incident photons. The measured photon yield at 15 MeV was 2 ×106 photons/MeV and, when coupled with the small source size, divergence, and pulse duration, results in a record peak brightness of 2 ×1019 photons/s/mm2/mrad2/0.1%bandwidth at 15 MeV photon energy. Current Affiliation: Stanford University/SLAC National Accelerator Laboratory.

  14. Nucleon resonance electroproduction at high momentum transers: Results from SLAC and suggestions for CEBAF

    SciTech Connect

    Keppel, C.

    1994-04-01

    Nucleon resonance electroproduction results from SLAC Experiment E14OX are presented. A CEBAF facility with doubled energy would enable similar high momentum transfer measurements to be made with greater accuracy. Of particular interest are the Delta P{sub 33}(1232) resonance form factor and R = {sigma}{sub L}/{sigma}{sub T}, the ratio of the longitudinal and transverse components of the cross section. A suggestion is made to study these quantities in conjunction with Bloom-Gilman duality.

  15. Relativistic klystrons for high-gradient accelerators

    SciTech Connect

    Westenskow, G.A.; Aalberts, D.P.; Boyd, J.K.; Deis, G.A.; Houck, T.L.; Orzechowski, T.J.; Ryne, R.D.; Yu, S.S. ); Allen, M.A.; Callin, R.S.; Deruyter, H.; Eppley, K.R.; Fant, K.S.; Fowkes, W.R.; Hoag, H.A.; Koontz, R.F.; Lavine, T.L.; Loew, G.A.; Miller, R.H.; Ruth, R.D.; Vlieks, A.E.; Wang, J.W. ); Haimson, J.; Mecklen

    1990-09-05

    Experimental work is being performed by collaborators at LLNL, SLAC, and LBL to investigate relativistic klystrons as a possible rf power source for future high-gradient accelerators. We have learned how to overcome or previously reported problem of high power rf pulse shortening and have achieved peak rf power levels of 330 MW using an 11.4-GHz high-gain tube with multiple output structures. In these experiments the rf pulse is of the same duration as the beam current pulse. In addition, experiments have been performed on two short sections of a high-gradient accelerator using the rf power from a relativistic klystron. An average accelerating gradient of 84 MV/m has been achieved with 80-MW of rf power.

  16. Anomalous electron loading in SLAC 5045 klystron and relativistic klystron input cavities

    SciTech Connect

    Koontz, R.F.; Fowkes, R.W.; Lavine, T.L.; Miller, R.H.; Vlieks, A.E.

    1989-03-01

    Recent studies of RF breakup and instability in the SLAC 5045 klystrons have revealed that many production klystrons show loading of the input cavity by low energy electrons even under cold cathode no beam conditions. Sometime after the onset of the RF drive pulse, the input cavity absorbs a portion of the incident RF drive that would otherwise be reflected from the not-beam-loaded cavity. This power absorption is a function of drive level, and of axial magnetic field surrounding the cavity. No power absorption is present when the axial magnetic field is zero. This same phenomenon has been observed in the input cavity of relativistic klystron experiments being conducted as part of the SLAC-LBL-LLNL development program. The phenomenon may be associated with RF breakup and RF instability in SLAC 5045 klystrons, and with unstable pulse shortening in the relativistic klystron experiments. This paper outlines some old and new observations of microwave beam device malfunctions that probably are associated with low energy electron fluxes in the vacuum environments of microwave power devices. 2 refs., 5 figs.

  17. Technological Issues and High Gradient Test Results on X-Band Molybdenum Accelerating Structures

    SciTech Connect

    Spataro, B.; Alesini, D.; Chimenti, V.; Dolgashev, V.; Haase, A.; Tantawi, S.G.; Higashi, Y.; Marrelli, C.; Mostacci, A.; Parodi, R.; Yeremian, A.D.; /SLAC

    2012-04-24

    Two 11.424 GHz single cell standing wave accelerating structures have been fabricated for high gradient RF breakdown studies. Both are brazed structures: one made from copper and the other from sintered molybdenum bulk. The tests results are presented and compared to those of similar devices constructed at SLAC (Stanford Linear Accelerator Center) and KEK (Ko Enerugi Kasokuki Kenkyu Kiko). The technological issues to build both sections are discussed.

  18. RF properties of periodic accelerating structures for linear colliders

    SciTech Connect

    Wang, J.W.

    1989-07-01

    With the advent of the SLAC electron-positron linear collider (SLC) in the 100 GeV center-of-mass energy range, research and development work on even higher energy machines of this type has started in several laboratories in the United States, Europe, the Soviet Union and Japan. These linear colliders appear to provide the only promising approach to studying e/sup /plus//e/sup /minus// physics at center-of-mass energies approaching 1 TeV. This thesis concerns itself with the study of radio frequency properties of periodic accelerating structures for linear colliders and their interaction with bunched beams. The topics that have been investigated are: experimental measurements of the energy loss of single bunches to longitudinal modes in two types of structures, using an equivalent signal on a coaxial wire to simulate the beam; a method of canceling the energy spread created within a single bunch by longitudinal wakefields, through appropriate shaping of the longitudinal charge distribution of the bunch; derivation of the complete transient beam-loading equation for a train of bunches passing through a constant-gradient accelerator section, with application to the calculation and minimization of multi-bunch energy spread; detailed study of field emission and radio frequency breakdown in disk-loaded structures at S-, C- and X-band frequencies under extremely high-gradient conditions, with special attention to thermal effects, radiation, sparking, emission of gases, surface damage through explosive emission and its possible control through RF-gas processing. 53 refs., 49 figs., 9 tabs.

  19. Acceleration in astrophysics

    SciTech Connect

    Colgate, S.A.

    1993-12-31

    The origin of cosmic rays and applicable laboratory experiments are discussed. Some of the problems of shock acceleration for the production of cosmic rays are discussed in the context of astrophysical conditions. These are: The presumed unique explanation of the power law spectrum is shown instead to be a universal property of all lossy accelerators; the extraordinary isotropy of cosmic rays and the limited diffusion distances implied by supernova induced shock acceleration requires a more frequent and space-filling source than supernovae; the near perfect adiabaticity of strong hydromagnetic turbulence necessary for reflecting the accelerated particles each doubling in energy roughly 10{sup 5} to {sup 6} scatterings with negligible energy loss seems most unlikely; the evidence for acceleration due to quasi-parallel heliosphere shocks is weak. There is small evidence for the expected strong hydromagnetic turbulence, and instead, only a small number of particles accelerate after only a few shock traversals; the acceleration of electrons in the same collisionless shock that accelerates ions is difficult to reconcile with the theoretical picture of strong hydromagnetic turbulence that reflects the ions. The hydromagnetic turbulence will appear adiabatic to the electrons at their much higher Larmor frequency and so the electrons should not be scattered incoherently as they must be for acceleration. Therefore the electrons must be accelerated by a different mechanism. This is unsatisfactory, because wherever electrons are accelerated these sites, observed in radio emission, may accelerate ions more favorably. The acceleration is coherent provided the reconnection is coherent, in which case the total flux, as for example of collimated radio sources, predicts single charge accelerated energies much greater than observed.

  20. Overview of accelerators in medicine

    SciTech Connect

    Lennox, A.J. |

    1993-06-01

    Accelerators used for medicine include synchrotrons, cyclotrons, betatrons, microtrons, and electron, proton, and light ion linacs. Some accelerators which were formerly found only at physics laboratories are now being considered for use in hospital-based treatment and diagnostic facilities. This paper presents typical operating parameters for medical accelerators and gives specific examples of clinical applications for each type of accelerator, with emphasis on recent developments in the field.

  1. Breakthrough: Fermilab Accelerator Technology

    ScienceCinema

    None

    2014-08-12

    There are more than 30,000 particle accelerators in operation around the world. At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Experimenting with unique polishing materials, a Fermilab team has now developed an efficient and environmentally friendly way of creating cavities that can propel particles with more than 30 million volts per meter.

  2. Breakthrough: Fermilab Accelerator Technology

    SciTech Connect

    2012-04-23

    There are more than 30,000 particle accelerators in operation around the world. At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Experimenting with unique polishing materials, a Fermilab team has now developed an efficient and environmentally friendly way of creating cavities that can propel particles with more than 30 million volts per meter.

  3. Germline Mutation in EXPH5 Implicates the Rab27B Effector Protein Slac2-b in Inherited Skin Fragility

    PubMed Central

    McGrath, John A.; Stone, Kristina L.; Begum, Rumena; Simpson, Michael A.; Dopping-Hepenstal, Patricia J.; Liu, Lu; McMillan, James R.; South, Andrew P.; Pourreyron, Celine; McLean, W.H. Irwin; Martinez, Anna E.; Mellerio, Jemima E.; Parsons, Maddy

    2012-01-01

    The Rab GTPase Rab27B and one of its effector proteins, Slac2-b (also known as EXPH5, exophilin-5), have putative roles in intracellular vesicle trafficking but their relevance to human disease is not known. By using whole-exome sequencing, we identified a homozygous frameshift mutation in EXPH5 in three siblings with inherited skin fragility born to consanguineous Iraqi parents. All three individuals harbor the mutation c.5786delC (p.Pro1929Leufs∗8) in EXPH5, which truncates the 1,989 amino acid Slac2-b protein by 52 residues. The clinical features comprised generalized scale-crusts and occasional blisters, mostly induced by trauma, as well as mild diffuse pigmentary mottling on the trunk and proximal limbs. There was no increased bleeding tendency, no neurologic abnormalities, and no increased incidence of infection. Analysis of an affected person's skin showed loss of Slac2-b immunostaining (C-terminal antibody), disruption of keratinocyte adhesion within the lower epidermis, and an increased number of perinuclear vesicles. A role for Slac2-b in keratinocyte biology was supported by findings of cytoskeletal disruption (mainly keratin intermediate filaments) and decreased keratinocyte adhesion in both keratinocytes from an affected subject and after shRNA knockdown of Slac2-b in normal keratinocytes. Slac2-b was also shown to colocalize with Rab27B and β4 integrin to early adhesion initiation sites in spreading normal keratinocytes. Collectively, our findings identify an unexpected role for Slac2-b in inherited skin fragility and expand the clinical spectrum of human disorders of GTPase effector proteins. PMID:23176819

  4. Plasma accelerators

    SciTech Connect

    Ruth, R.D.; Chen, P.

    1986-03-01

    In this paper we discuss plasma accelerators which might provide high gradient accelerating fields suitable for TeV linear colliders. In particular we discuss two types of plasma accelerators which have been proposed, the Plasma Beat Wave Accelerator and the Plasma Wake Field Accelerator. We show that the electric fields in the plasma for both schemes are very similar, and thus the dynamics of the driven beams are very similar. The differences appear in the parameters associated with the driving beams. In particular to obtain a given accelerating gradient, the Plasma Wake Field Accelerator has a higher efficiency and a lower total energy for the driving beam. Finally, we show for the Plasma Wake Field Accelerator that one can accelerate high quality low emittance beams and, in principle, obtain efficiencies and energy spreads comparable to those obtained with conventional techniques.

  5. Search for neutral, penetrating, metastable particles produced in the SLAC beam dump

    SciTech Connect

    Bjorken, J.

    1984-03-01

    A search was made for neutral objects which might be produced by 20 GeV electrons incident on the SLAC beam dump, penetrate the downstream natural shielding, and decay upstream of an electromagnetic shower calorimeter. With about 30 coulombs of electrons dumped, no candidate events were found above an energy of approx. 2 GeV. Preliminary analysis implies the 95% confidence level limit on the product of mass and lifetime of light axion-like bosons decaying primarily into two photons to be greater than 0.8 keV-sec. Preliminary limits on photino parameters are also given.

  6. Requirements for use of nonmedical x-ray generators at SLAC

    SciTech Connect

    Busick, D.D.

    1984-09-01

    The risks associated with use of x-ray equipment have long been recognized. While the relative frequency of x-ray damage is small, machine produced x-rays and large radiography sources continue to account for a large percentage of preventable radiation injuries reported worldwide. The intent of this report is to formalize SLAC's radiation safety program as it applies to radiation producing equipment (diffraction, fluorescence analysis and nondestructive testing). It does not apply to the two-mile linac, experimental areas or other x-ray producing equipment directly related to the high energy physics program. 4 refs., 3 figs., 1 tab.

  7. A 4 to 0.1 nm FEL Based on the SLAC Linac

    SciTech Connect

    Pellegrini, C.; /UCLA

    2012-06-05

    The author show that using existing electron gun technology and a high energy linac like the one at SLAC, it is possible to build a Free Electron Laser operating around the 4 nm water window. A modest improvement in the gun performance would further allow to extend the FEL to the 0.1 nm region. Such a system would produce radiation with a brightness many order of magnitude above that of any synchrotron radiation source, existing or under construction, with laser power in the multigawatt region and subpicosecond pulse length.

  8. Biology of the Mi-2/NuRD Complex in SLAC (Stemness, Longevity/Ageing, and Cancer)

    PubMed Central

    Zhang, Yue

    2011-01-01

    The dynamic chromatin activities of Mi-2/Nucleosome Remodeling and Histone deacetylation (Mi-2/NuRD) complexes in mammals are at the basis of current research on stemness, longevity/ageing, and cancer (4-2-1/SLAC), and have been widely studied over the past decade in mammals and the elegant model organism, Caenorhabditis elegans. Interestingly, a common emergent theme from these studies is that of distinct coregulator-recruited Mi-2/NuRD complexes largely orchestrating the 4-2-1/SLAC within a unique paradigm by maintaining genome stability via DNA repair and controlling three types of transcriptional programs in concert in a number of cellular, tissue, and organism contexts. Thus, the core Mi-2/NuRD complex plays a central role in 4-2-1/SLAC. The plasticity and robustness of 4-2-1/SLAC can be interpreted as modulation of specific coregulator(s) within cell-specific, tissue-specific, stage-specific, or organism-specific niches during stress induction, ie, a functional module and its networking, thereby conferring differential responses to different environmental cues. According to “Occam’s razor”, a simple theory is preferable to a complex one, so this simplified notion might be useful for exploring 4-2-1/SLAC with a holistic view. This thought could also be valuable in forming strategies for future research, and could open up avenues for cancer prevention and antiageing strategies. PMID:21523247

  9. [Experiment studies of electron-positron interactions at the Stanford Linear Accelerator Center]. Progress report, calendar year 1993

    SciTech Connect

    Hertzbach, S.S.; Kofler, R.R.

    1993-12-31

    The High Energy Physics group at the University of Massachusetts has continued its` program of experimental studies of electron-positron interactions at the Stanford Linear Accelerator Center (SLAC). The group activities have included: analysis of data taken between 1982 and 1990 with the TPC detector at the PEP facility, continuing data collection and data analysis using the SLC/SLD facility, planning for the newly approved B-factory at SLAC, and participation in design studies for future high energy linear colliders. This report will briefly summarize these activities.

  10. Diagnostics for induction accelerators

    SciTech Connect

    Fessenden, T.J.

    1996-04-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960`s to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore`s Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail.

  11. Guard cell SLAC1-type anion channels mediate flagellin-induced stomatal closure.

    PubMed

    Guzel Deger, Aysin; Scherzer, Sönke; Nuhkat, Maris; Kedzierska, Justyna; Kollist, Hannes; Brosché, Mikael; Unyayar, Serpil; Boudsocq, Marie; Hedrich, Rainer; Roelfsema, M Rob G

    2015-10-01

    During infection plants recognize microbe-associated molecular patterns (MAMPs), and this leads to stomatal closure. This study analyzes the molecular mechanisms underlying this MAMP response and its interrelation with ABA signaling. Stomata in intact Arabidopsis thaliana plants were stimulated with the bacterial MAMP flg22, or the stress hormone ABA, by using the noninvasive nanoinfusion technique. Intracellular double-barreled microelectrodes were applied to measure the activity of plasma membrane ion channels. Flg22 induced rapid stomatal closure and stimulated the SLAC1 and SLAH3 anion channels in guard cells. Loss of both channels resulted in cells that lacked flg22-induced anion channel activity and stomata that did not close in response to flg22 or ABA. Rapid flg22-dependent stomatal closure was impaired in plants that were flagellin receptor (FLS2)-deficient, as well as in the ost1-2 (Open Stomata 1) mutant, which lacks a key ABA-signaling protein kinase. By contrast, stomata of the ABA protein phosphatase mutant abi1-1 (ABscisic acid Insensitive 1) remained flg22-responsive. These data suggest that the initial steps in flg22 and ABA signaling are different, but that the pathways merge at the level of OST1 and lead to activation of SLAC1 and SLAH3 anion channels. PMID:25932909

  12. Personnel dose equivalent monitoring at SLAC using lithium-fluoride TLD's (thermoluminescent dosimeters)

    SciTech Connect

    Jenkins, T.M.; Busick, D.D.

    1987-03-01

    TLD's replaced film badges in the early 1970's for all dose equivalent monitoring, both neutron and photon, and for all locations at SLAC. The photon TLD's, composed of Li-7 loaded teflon discs, are calibrated using conventional gamma-ray sources; i.e., Co-60, Cs-137, etc. For these TLD's a nominal value of 1 nC/mrem is used, and is independent of source energy for 100 keV to 3 MeV. Since measured dose equivalents at SLAC are only a small fraction of the allowable levels, it was not deemed necessary to develop neutron dosimeters which would measure dose equivalent accurately for all possible neutron spectra. Today, wallet TLD's, composed of pairs of Li-7 and Li-6 discs, are used, with the Li-6 measuring only thermal neutrons; i.e., they aren't moderated in any way to make them sensitive to neutrons with energies greater than thermal. The assumption is made that there is a correlation between thermal neutron fluences and fast neutron fluences around the research area where almost all neutron doses (exclusive of sealed sources) are received. The calibration factor for these Li-6 TLD's is 1 nC/mrem of fast neutrons. The method of determining the validity of this calibration is the subject of this note. 4 refs., 9 figs., 1 tab.

  13. Parameters for the PEP-II B-Factory at SLAC in 2008

    SciTech Connect

    Seeman, J.; Akre, R.; Bellomo, P.; Bertsche, Kirk J.; Chai, Y.; Chestnut, R.; Clendenin, J.; DeBarger, S.; Decker, F.J.; Dorfan, J.; Ecklund, S.; Erickson, R.; Fisher, A.; Fox, J.; Heifets, S.; Himel, T.; Iverson, R.; Humphrey, R.; Irwin, J.; Klaisner, L.; Kharakh, D.; /SLAC /LBL, Berkeley /Frascati

    2011-11-22

    The PEP-II B-Factory at SLAC (3.1 GeV e{sup +} x 9.0 GeV e{sup -}) operated from 1999 to 2008, delivering luminosity to the BaBar experiment. The design luminosity was reached after one and a half years of operation. In the end PEP-II surpassed, by four times, its design luminosity reaching 1.21 x 10{sup 34} cm{sup -2}s{sup -1}. It also set world stored beam current records of 2.1 A e{sup -} and 3.2 A e{sup +}. Continuous injection was implemented with BaBar successfully taking data. The total delivered luminosity to the BaBar detector was 557.4 fb{sup -1} spanning five upsilon resonances. PEP-II was constructed by SLAC, LBNL, and LLNL with help from BINP, IHEP, the BaBar collaboration, and the US DOE OHEP.

  14. Biomedical accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    Freeman, Stewart P. H. T.; Vogel, John S.

    1995-05-01

    Ultrasensitive SIMS with accelerator based spectrometers has recently begun to be applied to biomedical problems. Certain very long-lived radioisotopes of very low natural abundances can be used to trace metabolism at environmental dose levels ( [greater-or-equal, slanted] z mol in mg samples). 14C in particular can be employed to label a myriad of compounds. Competing technologies typically require super environmental doses that can perturb the system under investigation, followed by uncertain extrapolation to the low dose regime. 41Ca and 26Al are also used as elemental tracers. Given the sensitivity of the accelerator method, care must be taken to avoid contamination of the mass spectrometer and the apparatus employed in prior sample handling including chemical separation. This infant field comprises the efforts of a dozen accelerator laboratories. The Center for Accelerator Mass Spectrometry has been particularly active. In addition to collaborating with groups further afield, we are researching the kinematics and binding of genotoxins in-house, and we support innovative uses of our capability in the disciplines of chemistry, pharmacology, nutrition and physiology within the University of California. The field can be expected to grow further given the numerous potential applications and the efforts of several groups and companies to integrate more the accelerator technology into biomedical research programs; the development of miniaturized accelerator systems and ion sources capable of interfacing to conventional HPLC and GMC, etc. apparatus for complementary chemical analysis is anticipated for biomedical laboratories.

  15. SLAC1 is required for plant guard cell S-type anion channel function in stomatal signalling

    PubMed Central

    Vahisalu, Triin; Kollist, Hannes; Wang, Yong-Fei; Nishimura, Noriyuki; Chan, Wai-Yin; Valerio, Gabriel; Lamminmäki, Airi; Brosché, Mikael; Moldau, Heino; Desikan, Radhika; Schroeder, Julian I.; Kangasjärvi, Jaakko

    2010-01-01

    Stomatal pores, formed by two surrounding guard cells in the epidermis of plant leaves, allow influx of atmospheric carbon dioxide in exchange for transpirational water loss. Stomata also restrict the entry of ozone—an important air pollutant that has an increasingly negative impact on crop yields, and thus global carbon fixation1 and climate change2. The aperture of stomatal pores is regulated by the transport of osmotically active ions and metabolites across guard cell membranes3,4. Despite the vital role of guard cells in controlling plant water loss3,4, ozone sensitivity1,2 and CO2 supply2,5–7, the genes encoding some of the main regulators of stomatal movements remain unknown. It has been proposed that guard cell anion channels function as important regulators of stomatal closure and are essential in mediating stomatal responses to physiological and stress stimuli3,4,8. However, the genes encoding membrane proteins that mediate guard cell anion efflux have not yet been identified. Here we report the mapping and characterization of an ozone-sensitive Arabidopsis thaliana mutant, slac1. We show that SLAC1 (SLOW ANION CHANNEL-ASSOCIATED 1) is preferentially expressed in guard cells and encodes a distant homologue of fungal and bacterial dicarboxylate/malic acid transport proteins. The plasma membrane protein SLAC1 is essential for stomatal closure in response to CO2, abscisic acid, ozone, light/dark transitions, humidity change, calcium ions, hydrogen peroxide and nitric oxide. Mutations in SLAC1 impair slow (S-type) anion channel currents that are activated by cytosolic Ca2+ and abscisic acid, but do not affect rapid (R-type) anion channel currents or Ca2+ channel function. A low homology of SLAC1 to bacterial and fungal organic acid transport proteins, and the permeability of S-type anion channels to malate9 suggest a vital role for SLAC1 in the function of S-type anion channels. PMID:18305484

  16. Tethered gravity laboratories study

    NASA Technical Reports Server (NTRS)

    Lucchetti, F.

    1989-01-01

    Variable Gravity Laboratory studies are discussed. The following subject areas are covered: (1) conceptual design and engineering analysis; (2) control strategies (fast crawling maneuvers, main perturbations and their effect upon the acceleration level); and (3) technology requirements.

  17. Inverse free electron laser accelerator

    SciTech Connect

    Fisher, A.; Gallardo, J.; Sandweiss, J.; van Steenbergen, A. )

    1992-07-01

    The study of the INVERSE FREE ELECTRON LASER, as a potential mode of electron acceleration, is being pursued at Brookhaven National Laboratory. Recent studies have focussed on the development of a low energy, high gradient, multi stage linear accelerator. The elementary ingredients for the IFEL interaction are the 50 MeV Linac e[sup [minus

  18. Inverse Free Electron Laser accelerator

    SciTech Connect

    Fisher, A.; Gallardo, J.; van Steenbergen, A. ); Sandweiss, J. )

    1992-09-01

    The study of the INVERSE FREE ELECTRON LASER, as a potential mode of electron acceleration, is being pursued at Brookhaven National Laboratory. Recent studies have focussed on the development of a low energy, high gradient, multi stage linear accelerator. The elementary ingredients for the IFEL interaction are the 50 MeV Linac e[sup [minus

  19. The Super-B Project Accelerator Status

    SciTech Connect

    Biagini, M.E.; Alesini, D.; Boni, R.; Boscolo, M.; Demma, T.; Drago, A.; Esposito, M.; Guiducci, S.; Marcellini, F.; Mazzitelli, G.; Preger, M.; Raimondi, P.; Sanelli, C.; Serio, M.; Stecchi, A.; Stella, A.; Tomassini, S.; Zobov, M.; Bertsche, K.; Brachmann, A.; Cai, Y.; /SLAC /Novosibirsk, IYF /Annecy, LAPP /LPSC, Grenoble /Orsay, LAL /Saclay /Pisa U. /CERN

    2011-08-17

    The SuperB project is an international effort aiming at building in Italy a very high luminosity e{sup +}e{sup -} (10{sup 36} cm{sup -2} sec{sup -1}) asymmetric collider at the Y(4S) energy in the CM. The accelerator design has been extensively studied and changed during the past year. The present design, based on the new collision scheme, with large Piwinski angle and the use of 'crab waist' sextupoles already successfully tested at the DA{Phi}NE {Phi}-Factory at LNF Frascati, provides larger flexibility, better dynamic aperture and spin manipulation sections in the Low Energy Ring (LER) for longitudinal polarization of the electron beam at the Interaction Point (IP). The Interaction Region (IR) has been further optimized in terms of apertures and reduced backgrounds in the detector. The injector complex design has been also updated. A summary of the project status will be presented in this paper. The SuperB collider can reach a peak luminosity of 10{sup 36} cm{sup -2} sec{sup -1} with beam currents and bunch lengths similar to those of the past and present e{sup +}e{sup -} Factories, through the use of smaller emittances and new scheme of crossing angle collision. The beams are stored in two rings at 6.7 GeV (HER) and 4.2 GeV (LER). Unique features of the project are the polarization of the electron beam in the LER and the possibility to decrease the energies for running at the {tau}/charm threshold. The option to reuse the PEP-II B-Factory (SLAC) hardware will allow reducing costs. The SuperB facility will require a big complex of civil infrastructure. The main construction, which will house the final part of the LINAC, the injection lines, the damping rings, and the storage rings, will be mainly underground. Two sites have been considered: the campus of Tor Vergata University near Frascati, and the INFN Frascati Laboratory. No decision has been made yet. A footprint of the possible SuperB layout on the LNF area is shown in Fig. 1.

  20. Dielectric Wakefield Accelerator Experiments at the SABER Facility

    SciTech Connect

    Kanareykin, A.; Thompson, M.C.; Berry, M.K.; Blumenfeld, I.; Decker, F.J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.H.; Kirby, N.A.; Siemann, Robert H.; Walz, D.R.; Badakov, H.; Cook, A.M.; Rosenzweig, J.B.; Tikhoplav, R.; Travish, G.; Muggli, P.; /Southern California U.

    2008-01-28

    Electron bunches with the unparalleled combination of high charge, low emittances, and short time duration, as first produced at the SLAC Final Focus Test Beam (FFTB), are foreseen to be produced at the SABER facility. These types of bunches have enabled wakefield driven accelerating schemes of multi-GV/m in plasmas. In the context of the Dielectric Wakefield Accelerators (DWA) such beams, having rms bunch length as short as 20 um, have been used to drive 100 um and 200 um ID hollow tubes above 20 GV/m surface fields. These FFTB tests enabled the measurement of a breakdown threshold in fused silica (with full data analysis still ongoing) [1]. With the construction and commissioning of the SABER facility at SLAC, new experiments would be made possible to test further aspects of DWAs including materials, tube geometrical variations, direct measurements of the Cerenkov fields, and proof of acceleration in tubes >10 cm in length. This collaboration will investigate breakdown thresholds and accelerating fields in new materials including CVD diamond. Here we describe the experimental plans, beam parameters, simulations, and progress to date as well as future prospects for machines based of DWA structures.

  1. First charge breeding of a rare-isotope beam with the electron-beam ion trap of the ReA post-accelerator at the National Superconducting Cyclotron Laboratory

    NASA Astrophysics Data System (ADS)

    Lapierre, A.; Schwarz, S.; Baumann, T. M.; Cooper, K.; Kittimanapun, K.; Rodriguez, A. J.; Sumithrarachchi, C.; Williams, S. J.; Wittmer, W.; Leitner, D.; Bollen, G.

    2014-02-01

    An electron-beam ion trap (EBIT) charge breeder is being brought into operation at the National Superconducting Cyclotron Laboratory at Michigan State University. The EBIT is part of the ReA post-accelerator for reacceleration of rare isotopes, which are thermalized in a gas "stopping" cell after being produced at high energy by projectile fragmentation. The ReA EBIT has a distinctive design; it is characterized by a high-current electron gun and a two-field superconducting magnet to optimize the capture and charge-breeding efficiency of continuously injected singly charged ion beams. Following a brief overview of the reaccelerator system and the ReA EBIT, this paper presents the latest commissioning results, particularly, charge breeding and reacceleration of the highly charged rare isotopes, 76Ga24 +, 25 +.

  2. Review of Activities using the Pulsed Neutron Facility and 2.5-GeV Electron Linac at Pohang Accelerator Laboratory

    SciTech Connect

    Kim, Guinyun; Lee, Manwoo; Kim, Kyung Sook; Yang, Sungchul; Kim, Eunae; Shvetshov, Valery; Cho, Moo-Hyun; Naik, Haladhara

    2011-12-13

    We report on activities using a pulsed neutron facility consisting of an electron linear accelerator, a water-cooled Ta target with a water moderator, and a 12 m time-of-flight path. It is possible to measure neutron total cross sections in the neutron energy range from 0.01 eV to a few hundred eV by using the neutron time-of-flight method; photo-neutron cross sections can also measure by using the bremsstrahlung from the electron linac. A {sup 6}LiZnS(Ag) glass scintillator was used as a neutron detector. The neutron flight path from the water-cooled Ta target to the neutron detector was 12.1 m. In this paper, we report total cross sections of Nb and also resonance parameters obtained using the SAMMY fitting program. The present results are compared with the previous experimental results and the evaluated data in ENDF/B-VII. We also report on the mass-yield distribution of fission products in the 2.5-GeV bremsstrahlung-induced fission of {sup nat}Pb and {sup 209}Bi measured at the 2.5-GeV electron linac using a recoil catcher and an off-line {gamma}-ray spectrometric technique.

  3. A 12 GHZ 50 MW Klystron for Support of Accelerator Research

    SciTech Connect

    Sprehn, Daryl; Haase, Andrew; Jensen, Aaron; Jongewaard, Erik; Nantista, Christopher; Vlieks, Arnold; /SLAC

    2011-05-31

    A 12 GHz 50MW X-band klystron is under development at the SLAC National Accelerator Laboratory Klystron Department. The klystron will be fabricated to support programs currently underway at three European Labs; CERN, PSI, and INFN Trieste. The choice of frequency selection was due to the CLIC RF frequency changing from 30 GHz to the European X-band frequency of 11.99 GHz in 2008. Since the Klystron Department currently builds 50MW klystrons at 11.424 GHz known collectively as the XL4 klystrons, it was deemed cost-effective to utilize many XL4 components by leaving the gun, electron beam transport, solenoid magnet and collector unchanged. To realize the rf parameters required, the rf cavities and rf output hardware were necessarily altered. Some improvements to the rf design have been made to reduce operating gradients and increase reliability. Changes in the multi-cell output structure, waveguide components, and the window will be discussed along with testing of the devices. Five klystrons known as XL5 klystrons are scheduled for production over the next two years.

  4. Theory of factors limiting high gradient operation of warm accelerating structures

    SciTech Connect

    Nusinovich, Gregory S.

    2014-07-22

    This report consists of two parts. In the first part we describe a study of the heating of microprotrusions on surfaces of accelerating structures. This ;process is believed to lead to breakdown in these structures. Our study revealed that for current accelerator parameters melting should not occur due to space charge limitations of the current emitted by a protrusion. The second part describes a novel concept to develop THz range sources based on harmonic cyclotron masers for driving future colliders. This work was stimulated by a recent request of SLAC to develop high power, high-efficiency sources of sub-THz radiation for future high-gradient accelerators.

  5. Laboratory Astrophysics Using High Intensity Particle and Photon Beams

    SciTech Connect

    Chen, Pisin

    2001-12-12

    History has shown that the symbiosis between direct observations and laboratory studies is instrumental in the progress of astrophysics. Recent years have seen growing interests in the laboratory investigation of astrophysical phenomena that can be addressed by high densities and advancement of technologies in lasers as well as high-energy particle beams. We will give examples on how frontier phenomena such as black holes, supernovae, gamma ray bursts, ultra high-energy cosmic rays, etc., can be investigated in the laboratory setting. Finally, we describe a possible laboratory astrophysics facility to be developed at SLAC.

  6. Laboratory Astrophysics Using High Intensity Particle and Photon Beams

    SciTech Connect

    Chen, Pisin

    2009-12-12

    History has shown that the symbiosis between direct observations and laboratory studies is instrumental in the progress of astrophysics. Recent years have seen growing interests in the laboratory investigation of astrophysical phenomena that can be addressed by high densities and advancement of technologies in lasers as well as high-energy particle beams. We will give examples on how frontier phenomena such as black holes, supernovae, gamma ray bursts, ultra high-energy cosmic rays, etc., can be investigated in the laboratory setting. Finally, we describe a possible laboratory astrophysics facility to be developed at SLAC.

  7. Integrating Newer Technology Software Systems into the SLAC Legacy Control System - Two Case Histories and New CMLOG Developments

    SciTech Connect

    MacKenzie, Ronald R.

    2001-12-11

    It has been the goal of SLAC Controls Software to offload processing from the aging Alpha/VMS based control system onto machines that are more widely accepted and used. An additional goal has been to provide more modern software tools to our user community. This paper presents two software products which satisfy those goals.

  8. Test of QED using a laser at the SLAC final focus test beam

    SciTech Connect

    Spencer, J.E.

    1992-04-01

    Experiment {number sign}144 at SLAC has three parts: the search for low-mass states excited in {gamma}{gamma} collisions and observed in pair decay, the study of nonlinear, nonperturbative QED in {gamma}e and {gamma}{gamma} collisions, and its possible applications to general purpose linear colliders. Such colliders could produce the full range of J{sub q{center dot}{center dot}{bar q}}/{sup PC} states, leptoquarks J{sub l{center dot}{center dot}{bar q}}/{sup PC}, the particles of supersymmetry, the top quark or Higgs. However, to realize them a number of technical problems need resolution that are addressed in E144 together with interesting possibilities for highly polarized, high brightness {gamma}/{sup {yields}} e{sup {yields}{plus minus}} beams that are needed for electroweak studies.

  9. Test of QED using a laser at the SLAC final focus test beam

    SciTech Connect

    Spencer, J.E.

    1992-04-01

    Experiment {number_sign}144 at SLAC has three parts: the search for low-mass states excited in {gamma}{gamma} collisions and observed in pair decay, the study of nonlinear, nonperturbative QED in {gamma}e and {gamma}{gamma} collisions, and its possible applications to general purpose linear colliders. Such colliders could produce the full range of J{sub q{center_dot}{center_dot}{bar q}}/{sup PC} states, leptoquarks J{sub l{center_dot}{center_dot}{bar q}}/{sup PC}, the particles of supersymmetry, the top quark or Higgs. However, to realize them a number of technical problems need resolution that are addressed in E144 together with interesting possibilities for highly polarized, high brightness {gamma}/{sup {yields}} e{sup {yields}{plus_minus}} beams that are needed for electroweak studies.

  10. Lattice design for the high energy ring of the SLAC B-Factory (PEP-II)

    SciTech Connect

    Donald, M.H.R.; Cai, Y.; Irwin, J.

    1995-04-01

    The design of the lattice for the High Energy Ring (HER) of the SLAC B-Factory has several special features, notably provision for octupole compensation of amplitude dependent tune shift effects and a beta-beat scheme for semi-local chromaticity correction. In the arcs adjacent to the interaction point (IP) the beta functions are enhanced to allow the use of non-interlaced sextupoles to compensate the chromaticity of the interaction region. A closed bump of beta {open_quotes}mismatch{close_quotes} is generated by two vertically focusing quadrupoles spaced 2 betatron wavelengths apart. The beta-beat has two advantages: it enhances the ratio between the horizontal and vertical beta functions at the sextupoles and, because of the locally higher beta function, allows weaker sextupoles to be used. The standard design uses a 60 degree/cell lattice but a 90 degree/cell lattice may also be used if lower emittances and momentum compaction factor are desired.

  11. The Linac Coherent Light Source at SLAC. Radiological Considerations and Shielding calculations

    SciTech Connect

    Mao, X.S.; Fasso, A.; Nakao, N.; Rokni, S.H.; Vincke, H.; /SLAC

    2005-12-02

    The Linac Coherent Light Source (LCLS) at SLAC will be the world's first X-ray free electron laser when it becomes operational in 2009. Pulses of X-ray laser light from LCLS will be many orders of magnitude brighter and several orders of magnitude shorter than what can be produced by other X-ray sources available in the world. These characteristics will enable frontier new science in many areas. This paper describes the LCLS beam parameters and its lay-out. Results of the Monte Carlo calculations for the shielding design of the electron dump line, radiation damage to undulator, the residual radiation and the soil activation around the electron dump are presented.

  12. Analysis of the Wakefield Effects in the PEP-II SLAC B-FACTORY

    SciTech Connect

    Novokhatski, A; Seeman, J.; Sullivan, M.; Wienands, U.; /SLAC

    2009-07-06

    We present the history and analysis of different wake field effects throughout the operational life of the PEP-II SLAC B-factory. Although the impedance of the high and low energy rings is small, the intense high current beams generated a lot of power. The effects from these wake fields are: heating and damage of vacuum beam chamber elements like RF seals, vacuum valves , shielded bellows, BPM buttons and ceramic tiles; vacuum spikes, vacuum instabilities and high detector background; beam longitudinal and transverse instabilities. We also discuss the methods used to eliminate these effects. Results of this analysis and the PEP-II experience may be very useful in the design of new storage rings and light sources.

  13. 3D Modeling Activity for Novel High Power Electron Guns at SLAC

    SciTech Connect

    Krasnykh, Anatoly

    2003-07-29

    The next generation of powerful electronic devices requires new approaches to overcome the known limitations of existing tube technology. Multi-beam and sheet beam approaches are novel concepts for the high power microwave devices. Direct and indirect modeling methods are being developed at SLAC to meet the new requirements in the 3D modeling. The direct method of solving of Poisson's equations for the multi-beam and sheet beam guns is employed in the TOPAZ 3D tool. The combination of TOPAZ 2D and EGUN (in the beginning) with MAFIA 3D and MAGIC 3D (at the end) is used in an indirect method to model the high power electron guns. Both methods complement each other to get reliable representation of the beam trajectories. Several gun ideas are under consideration at the present time. The collected results of these simulations are discussed.

  14. Computer modelling of bunch-by-bunch feedback for the SLAC B-factory design

    SciTech Connect

    Briggs, D.; Fox, J.D.; Hosseini, W.; Klaisner, L.; Morton, P.; Pellegrin, J.L.; Thompson, K.A. ); Lambertson, G. )

    1991-05-01

    The SLAC B-factory design, with over 1600 high current bunches circulating in each ring, will require a feedback system to avoid coupled-bunch instabilities. A computer model of the storage ring, including the RF system, wave fields, synchrotron radiation loss, and the bunch-by-bunch feedback system is presented. The feedback system model represents the performance of a fast phase detector front end (including system noise and imperfections), a digital filter used to generate a correction voltage, and a power amplifier and beam kicker system. The combined ring-feedback system model is used to study the feedback system performance required to suppress instabilities and to quantify the dynamics of the system. Results are presented which show the time development of coupled bunch instabilities and the damping action of the feedback system. 3 refs., 5 figs., 2 tabs.

  15. Accelerator and electrodynamics capability review

    SciTech Connect

    Jones, Kevin W

    2010-01-01

    Los Alamos National Laboratory (LANL) uses capability reviews to assess the science, technology and engineering (STE) quality and institutional integration and to advise Laboratory Management on the current and future health of the STE. Capability reviews address the STE integration that LANL uses to meet mission requirements. The Capability Review Committees serve a dual role of providing assessment of the Laboratory's technical contributions and integration towards its missions and providing advice to Laboratory Management. The assessments and advice are documented in reports prepared by the Capability Review Committees that are delivered to the Director and to the Principal Associate Director for Science, Technology and Engineering (PADSTE). Laboratory Management will use this report for STE assessment and planning. LANL has defined fifteen STE capabilities. Electrodynamics and Accelerators is one of the seven STE capabilities that LANL Management (Director, PADSTE, technical Associate Directors) has identified for review in Fiscal Year (FY) 2010. Accelerators and electrodynamics at LANL comprise a blend of large-scale facilities and innovative small-scale research with a growing focus on national security applications. This review is organized into five topical areas: (1) Free Electron Lasers; (2) Linear Accelerator Science and Technology; (3) Advanced Electromagnetics; (4) Next Generation Accelerator Concepts; and (5) National Security Accelerator Applications. The focus is on innovative technology with an emphasis on applications relevant to Laboratory mission. The role of Laboratory Directed Research and Development (LDRD) in support of accelerators/electrodynamics will be discussed. The review provides an opportunity for interaction with early career staff. Program sponsors and customers will provide their input on the value of the accelerator and electrodynamics capability to the Laboratory mission.

  16. SLAC E155 and E155x Numeric Data Results and Data Plots: Nucleon Spin Structure Functions

    DOE Data Explorer

    The nucleon spin structure functions g1 and g2 are important tools for testing models of nucleon structure and QCD. Experiments at CERN, DESY, and SLAC have measured g1 and g2 using deep inelastic scattering of polarized leptons on polarized nucleon targets. The results of these experiments have established that the quark component of the nucleon helicity is much smaller than naive quark-parton model predictions. The Bjorken sum rule has been confirmed within the uncertainties of experiment and theory. The experiment E155 at SLAC collected data in March and April of 1997. Approximately 170 million scattered electron events were recorded to tape. (Along with several billion inclusive hadron events.) The data were collected using three independent fixed-angle magnetic spectrometers, at approximately 2.75, 5.5, and 10.5 degrees. The momentum acceptance of the 2.75 and 5.5 degree spectrometers ranged from 10 to 40 GeV, with momentum resolution of 2-4%. The 10.5 degree spectrometer, new for E155, accepted events of 7 GeV to 20 GeV. Each spectrometer used threshold gas Cerenkov counters (for particle ID), a segmented lead-glass calorimeter (for energy measurement and particle ID), and plastic scintillator hodoscopes (for tracking and momentum measurement). The polarized targets used for E155 were 15NH3 and 6LiD, as targets for measuring the proton and deuteron spin structure functions respectively. Experiment E155x recently concluded a successful two-month run at SLAC. The experiment was designed to measure the transverse spin structure functions of the proton and deuteron. The E155 target was also recently in use at TJNAF's Hall C (E93-026) and was returned to SLAC for E155x. E155x hopes to reduce the world data set errors on g2 by a factor of three. [Copied from http://www.slac.stanford.edu/exp/e155/e155_nickeltour.html, an information summary linked off the E155 home page at http://www.slac.stanford.edu/exp/e155/e155_home.html. The extension run, E155x, also makes

  17. HIGH GRADIENT INDUCTION ACCELERATOR

    SciTech Connect

    Caporaso, G J; Sampayan, S; Chen, Y; Blackfield, D; Harris, J; Hawkins, S; Holmes, C; Krogh, M; Nelson, S; Nunnally, W; Paul, A; Poole, B; Rhodes, M; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J

    2007-06-21

    A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase the average accelerating gradient by at least an order of magnitude over that of existing induction machines. The machine is based on the use of high gradient vacuum insulators, advanced dielectric materials and switches and is stimulated by the desire for compact flash x-ray radiography sources. Research describing an extreme variant of this technology aimed at proton therapy for cancer will be described. Progress in applying this technology to several applications will be reviewed.

  18. Accelerated Reader.

    ERIC Educational Resources Information Center

    Education Commission of the States, Denver, CO.

    This paper provides an overview of Accelerated Reader, a system of computerized testing and record-keeping that supplements the regular classroom reading program. Accelerated Reader's primary goal is to increase literature-based reading practice. The program offers a computer-aided reading comprehension and management program intended to motivate…

  19. Detecting Energy Modulation in a Dielectric Laser Accelerator

    SciTech Connect

    Lukaczyk, Louis

    2015-08-21

    The Dielectric Laser Acceleration group at SLAC uses micro-fabricated dielectric grating structures and conventional infrared lasers to accelerator electrons. These structures have been estimated to produce an accelerating gradient up to 2 orders of magnitude greater than that produced by conventional RF accelerators. The success of the experiment depends on both the laser damage threshold of the structure and the timing overlap of femtosecond duration laser pulses with the electron bunch. In recent dielectric laser acceleration experiments, the laser pulse was shorter both temporally and spatially than the electron bunch. As a result, the laser is theorized to have interacted with only a small portion of the electron bunch. The detection of this phenomenon, referred to as partial population modulation, required a new approach to the data analysis of the electron energy spectra. A fitting function was designed to separate the accelerated electron population from the un-accelerated electron population. The approach was unsuccessful in detecting acceleration in the partial population modulation data. However, the fitting functions provide an excellent figure of merit for previous data known to contain signatures of acceleration.

  20. Rail accelerator research at Lewis Research Center

    NASA Technical Reports Server (NTRS)

    Kerslake, W. R.; Cybyk, B. Z.

    1982-01-01

    A rail accelerator was chosen for study as an electromagnetic space propulsion device because of its simplicity and existing technology base. The results of a mission feasibility study using a large rail accelerator for direct launch of ton-size payloads from the Earth's surface to space, and the results of initial tests with a small, laboratory rail accelerator are presented. The laboratory rail accelerator has a bore of 3 by 3 mm and has accelerated 60 mg projectiles to velocities of 300 to 1000 m/s. Rail materials of Cu, W, and Mo were tested for efficiency and erosion rate.

  1. Ultra-High Gradient Dielectric Wakefield Accelerator Experiments

    SciTech Connect

    Thompson, M. C.; Badakov, H.; Rosenzweig, J. B.; Travis, G.; Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; Muggli, P.; Scott, A.; Yoder, R.

    2006-11-27

    Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., {sigma}z = 20 {mu}m at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 {mu}m / OD = 325 {mu}m). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.

  2. Ultra-High Gradient Dielectric Wakefield Accelerator Experiments

    NASA Astrophysics Data System (ADS)

    Thompson, M. C.; Badakov, H.; Rosenzweig, J. B.; Travis, G.; Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; Muggli, P.; Scott, A.; Yoder, R.

    2006-11-01

    Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., σz = 20 μm at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 μm / OD = 325 μm). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.

  3. Ultra-High Gradient Dielectric Wakefield Accelerator Experiments

    SciTech Connect

    Thompson, M.C.; Badakov, H.; Rosenzweig, J.B.; Travish, G.; Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; Muggli, P.; Scott, A.; Yoder, R.; /LLNL, Livermore /UCLA /SLAC /Southern California U. /UC, Santa Barbara /Manhattan Coll., Riverdale

    2007-03-27

    Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., {sigma}{sub z} = 20 {micro}m at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 {micro}m/OD = 325 {micro}m). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.

  4. Ultra-High Gradient Dielectric Wakefield Accelerator Experiments

    SciTech Connect

    Thompson, M C; Badakov, H; Rosenzweig, J B; Travish, G; Hogan, M; Ischebeck, R; Kirby, N; Siemann, R; Walz, D; Muggli, P; Scott, A; Yoder, R

    2006-08-04

    Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., {sigma}{sub z} = 20 {micro}m at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 {micro}m/OD = 325 {micro}m). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.

  5. Microwave inverse Cerenkov accelerator

    SciTech Connect

    Zhang, T.B.; Marshall, T.C.; LaPointe, M.A.; Hirshfield, J.L.

    1997-03-01

    A Microwave Inverse Cerenkov Accelerator (MICA) is currently under construction at the Yale Beam Physics Laboratory. The accelerating structure in MICA consists of an axisymmetric dielectrically lined waveguide. For the injection of 6 MeV microbunches from a 2.856 GHz RF gun, and subsequent acceleration by the TM{sub 01} fields, particle simulation studies predict that an acceleration gradient of 6.3 MV/m can be achieved with a traveling-wave power of 15 MW applied to the structure. Synchronous injection into a narrow phase window is shown to allow trapping of all injected particles. The RF fields of the accelerating structure are shown to provide radial focusing, so that longitudinal and transverse emittance growth during acceleration is small, and that no external magnetic fields are required for focusing. For 0.16 nC, 5 psec microbunches, the normalized emittance of the accelerated beam is predicted to be less than 5{pi}mm-mrad. Experiments on sample alumina tubes have been conducted that verify the theoretical dispersion relation for the TM{sub 01} mode over a two-to-one range in frequency. No excitation of axisymmetric or non-axisymmetric competing waveguide modes was observed. High power tests showed that tangential electric fields at the inner surface of an uncoated sample of alumina pipe could be sustained up to at least 8.4 MV/m without breakdown. These considerations suggest that a MICA test accelerator can be built to examine these predictions using an available RF power source, 6 MeV RF gun and associated beam line. {copyright} {ital 1997 American Institute of Physics.}

  6. Site- and kinase-specific phosphorylation-mediated activation of SLAC1, a guard cell anion channel stimulated by abscisic acid.

    PubMed

    Maierhofer, Tobias; Diekmann, Marion; Offenborn, Jan Niklas; Lind, Christof; Bauer, Hubert; Hashimoto, Kenji; S Al-Rasheid, Khaled A; Luan, Sheng; Kudla, Jörg; Geiger, Dietmar; Hedrich, Rainer

    2014-09-01

    Under drought stress, abscisic acid (ABA) triggers closure of leaf cell pores called stomata, which are formed by two specialized cells called guard cells in plant epidermis. Two pathways downstream of ABA stimulate phosphorylation of the S-type anion channels SLAC1 (slow anion channel associated 1) and SLAH3 (SLAC1 homolog 3), which causes these channels to open, reducing guard cell volume and triggering stomatal closure. One branch involves OST1 (open stomata 1), a calcium-independent SnRK2-type kinase, and the other branch involves calcium-dependent protein kinases of the CPK (calcium-dependent protein kinase) family. We used coexpression analyses in Xenopus oocytes to show that the calcineurin B-like (CBL) calcium sensors CBL1 and CBL9 and their interacting protein kinase CIPK23 also triggered SLAC1 and SLAH3 opening. We analyzed whether regulation of SLAC1 opening by these different families of kinases involved the same or different sites on SLAC1 by measuring channel conductance of SLAC1 with mutations in the putative phosphorylation sites in the amino or carboxyl termini coexpressed with specific kinases in Xenopus oocytes. SLAC1 mutants lacking the OST1-phosphorylated site were still activated by CPK or by CBL/CIPK complexes. Phosphorylation and activation of SLAC1 by any of the kinases were inhibited by the phosphatase ABI1 (ABA insensitive 1), which is inactivated in response to ABA signaling. These findings identified CBL/CIPK complexes as potential regulators of stomatal aperture through S-type anion channels and indicated that phosphorylation at distinct sites enables SLAC1 activation by both calcium-dependent and calcium-independent pathways downstream of ABA. PMID:25205850

  7. Accelerator simulation of astrophysical processes

    NASA Technical Reports Server (NTRS)

    Tombrello, T. A.

    1983-01-01

    Phenomena that involve accelerated ions in stellar processes that can be simulated with laboratory accelerators are described. Stellar evolutionary phases, such as the CNO cycle, have been partially explored with accelerators, up to the consumption of He by alpha particle radiative capture reactions. Further experimentation is indicated on reactions featuring N-13(p,gamma)O-14, O-15(alpha, gamma)Ne-19, and O-14(alpha,p)F-17. Accelerated beams interacting with thin foils produce reaction products that permit a determination of possible elemental abundances in stellar objects. Additionally, isotopic ratios observed in chondrites can be duplicated with accelerator beam interactions and thus constraints can be set on the conditions producing the meteorites. Data from isotopic fractionation from sputtering, i.e., blasting surface atoms from a material using a low energy ion beam, leads to possible models for processes occurring in supernova explosions. Finally, molecules can be synthesized with accelerators and compared with spectroscopic observations of stellar winds.

  8. Design of the detuned accelerator structure

    SciTech Connect

    Wang, J.W.; Nelson, E.M.

    1993-05-01

    This is a summary of the design procedure for the detuned accelerator structure for SLAC's Next Linear Collider (NLC) program. The 11.424 GHz accelerating mode of each cavity must be synchronous with the beam. The distribution of the disk thicknesses and lowest synchronous dipole mode frequencies of the cavities in the structure is Gaussian in order to reduce the effect of wake fields. The finite element field solver YAP calculated the accelerating mode frequency and the lowest synchronous dipole mode frequency for various cavity diameters, aperture diameters and disk thicknesses. Polynomial 3-parameter fits are used to calculate the dimensions for a 1.8 m detuned structure. The program SUPERFISH was used to calculate the shunt impedances, quality factors and group velocities. The RF parameters of the section like filling time, attenuation factor, accelerating gradient and maximum surface field along the section are evaluated. Error estimates will be discussed and comparisons with conventional constant gradient and constant impedance structures will be presented.

  9. LINEAR ACCELERATOR

    DOEpatents

    Colgate, S.A.

    1958-05-27

    An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.

  10. Performance Limiting Effects in X-Band Accelerators

    SciTech Connect

    Wang Faya; Adolphsen, Chris; Nantista, Christopher

    2010-11-04

    Acceleration gradient is a critical parameter for the design of future TeV-scale linear colliders. The major obstacle to higher gradient in room-temperature accelerators is rf breakdown, which is still a very mysterious phenomenon that depends on the geometry and material of the accelerator as well as the input power and operating frequency. Pulsed heating has been associated with breakdown for many years however there have been no experiments that clearly separate field and heating effects on the breakdown rate. Recently, such experiments have been performed at SLAC with both standing-wave and travelling-wave structures. These experiments have demonstrated that pulsed heating is limiting the gradient. Also, a dual-moded cavity has been designed to better distinguish the electric field, magnetic field and pulsed heating effects on breakdown.

  11. SIMULATING ACCELERATOR STRUCTURE OPERATION AT HIGH POWER

    SciTech Connect

    Ivanov, V

    2004-09-15

    The important limiting factors in high-gradient accelerator structure operation are dark current capture, RF breakdown and electron multipacting. These processes involve both primary and secondary electron field emission and produce plasma and X-rays. To better understand these phenomena, they have simulated dark current generation and transport in a linac structure and a square-bend waveguide, both high power tested at SLAC. For these simulations, they use the parallel, time-domain, unstructured-grid code Tau3P and the particle tracking module Track3P. In this paper, they present numerical results and their comparison with measurements on energy spectrum of electrons transmitted in a 30-cell structure and of X-rays emitted from the square-bend waveguide.

  12. The Linac Cooherent Light Source (LCLS) Accelerator

    SciTech Connect

    Wu, Juhao; Emma, P.; /SLAC

    2007-03-21

    The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) based on the final kilometer of the Stanford Linear Accelerator. Such an FEL requires a high energy, high brightness electron beam to drive the FEL instability to saturation. When fed by an RF-photocathode gun, and modified to include two bunch compressor chicanes, the SLAC linac will provide such a high quality beam at 14 GeV and 1-{micro}m normalized emittance. In this paper, we report on recent linac studies, including beam stability and tolerances, longitudinal and transverse feedback systems, conventional and time-resolved diagnostics, and beam collimation systems. Construction and installation of the injector through first bunch compressor will be completed by December 2006, and electron commissioning is scheduled to begin in January of 2007.

  13. Acceleration switch

    DOEpatents

    Abbin, J.P. Jr.; Devaney, H.F.; Hake, L.W.

    1979-08-29

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  14. Acceleration switch

    DOEpatents

    Abbin, Jr., Joseph P.; Devaney, Howard F.; Hake, Lewis W.

    1982-08-17

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  15. ION ACCELERATOR

    DOEpatents

    Bell, J.S.

    1959-09-15

    An arrangement for the drift tubes in a linear accelerator is described whereby each drift tube acts to shield the particles from the influence of the accelerating field and focuses the particles passing through the tube. In one embodiment the drift tube is splii longitudinally into quadrants supported along the axis of the accelerator by webs from a yoke, the quadrants. webs, and yoke being of magnetic material. A magnetic focusing action is produced by energizing a winding on each web to set up a magnetic field between adjacent quadrants. In the other embodiment the quadrants are electrically insulated from each other and have opposite polarity voltages on adjacent quadrants to provide an electric focusing fleld for the particles, with the quadrants spaced sufficienily close enough to shield the particles within the tube from the accelerating electric field.

  16. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  17. Energy Doubling of 42 GeV Electrons in a Meter-scale Plasma Wakefield Accelerator

    SciTech Connect

    Blumenfeld, Ian; Clayton, Christopher E.; Decker, Franz-Josef; Hogan, Mark J.; Huang, Chengkun; Ischebeck, Rasmus; Iverson, Richard; Joshi, Chandrashekhar; Katsouleas, Thomas; Kirby, Neil; Lu, Wei; Marsh, Kenneth A.; Mori, Warren B.; Muggli, Patric; Oz, Erdem; Siemann, Robert H.; Walz, Dieter; Zhou, Miaomiao; /SLAC /UCLA /Southern California U.

    2007-03-14

    The energy frontier of particle physics is several trillion electron volts, but colliders capable of reaching this regime (such as the Large Hadron Collider and the International Linear Collider) are costly and time-consuming to build; it is therefore important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators, a drive beam (either laser or particle) produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultrahigh accelerating fields over a substantial length to achieve a significant energy gain. Here we show that an energy gain of more than 42 GeV is achieved in a plasma wakefield accelerator of 85 cm length, driven by a 42 GeV electron beam at the Stanford Linear Accelerator Center (SLAC). The results are in excellent agreement with the predictions of three-dimensional particle-in-cell simulations. Most of the beam electrons lose energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of {approx} 52GV m{sup -1}. This effectively doubles their energy, producing the energy gain of the 3-km-long SLAC accelerator in less than a meter for a small fraction of the electrons in the injected bunch. This is an important step towards demonstrating the viability of plasma accelerators for high-energy physics applications.

  18. Technical Challenges and Scientific Payoffs of Muon BeamAccelerators for Particle Physics

    SciTech Connect

    Zisman, Michael S.

    2007-09-25

    Historically, progress in particle physics has largely beendetermined by development of more capable particle accelerators. Thistrend continues today with the recent advent of high-luminosityelectron-positron colliders at KEK and SLAC operating as "B factories,"the imminent commissioning of the Large Hadron Collider at CERN, and theworldwide development effort toward the International Linear Collider.Looking to the future, one of the most promising approaches is thedevelopment of muon-beam accelerators. Such machines have very highscientific potential, and would substantially advance thestate-of-the-art in accelerator design. A 20-50 GeV muon storage ringcould serve as a copious source of well-characterized electron neutrinosor antineutrinos (a Neutrino Factory), providing beams aimed at detectorslocated 3000-7500 km from the ring. Such long baseline experiments areexpected to be able to observe and characterize the phenomenon ofcharge-conjugation-parity (CP) violation in the lepton sector, and thusprovide an answer to one of the most fundamental questions in science,namely, why the matter-dominated universe in which we reside exists atall. By accelerating muons to even higher energies of several TeV, we canenvision a Muon Collider. In contrast with composite particles likeprotons, muons are point particles. This means that the full collisionenergy is available to create new particles. A Muon Collider has roughlyten times the energy reach of a proton collider at the same collisionenergy, and has a much smaller footprint. Indeed, an energy frontier MuonCollider could fit on the site of an existing laboratory, such asFermilab or BNL. The challenges of muon-beam accelerators are related tothe facts that i) muons are produced as a tertiary beam, with very large6D phase space, and ii) muons are unstable, with a lifetime at rest ofonly 2 microseconds. How these challenges are accommodated in theaccelerator design will be described. Both a Neutrino Factory and a Muon

  19. LINAC for ADS application - accelerator technologies

    SciTech Connect

    Garnett, Robert W; Sheffreld, Richard L

    2009-01-01

    Sifnificant high-current, high-intensity accelerator research and development have been done in the recent past in the US, centered primarily at Los Alamos National Laboratory. These efforts have included designs for the Accelerator Production of Tritium Project, Accelerator Transmutation of Waste, and Accelerator Driven Systems, as well as many others. This past work and some specific design principles that were developed to optimie linac designs for ADS and other high-intensity applications will be discussed briefly.

  20. Development of Modulator Pulse Stability Measurement Device and Test Results at SLAC

    SciTech Connect

    Huang, C.; Burkhart, C.; Kemp, M.; Morris, B.; Beukers, T.; Ciprian, R.; Nguyen, M.; /SLAC

    2011-08-19

    In this paper, the development of a pulse stability measurement device is presented. The measurement accuracy is better than 250uV, about 4.2ppm of a typical 60V input pulse. Pulse signals up to +/- 80V peak can be measured. The device works together with an oscilloscope. The primary function of the measurement device is to provide a precision offset, such that variations in the flattop of the modulator voltage pulse can be accurately resolved. The oscilloscope records the difference between the pulse flattop and the reference for a series of waveforms. The scope math functions are utilized to calculate the rms variations over the series. The frequency response of the device is characterized by the measured cutoff frequency of about 6.5MHz. In addition to detailing the design and calibration of the precision pulse stability device, measurements of SLAC line-type linac modulators and recently developed induction modulators will be presented. Factors affecting pulse stability will be discussed.

  1. A Proof-of-Principle Echo-enabled Harmonic Generation Free Electron Laser Experiment at SLAC

    SciTech Connect

    Pernet, Pierre-Louis

    2010-06-24

    With the advent of X-ray Free Electron Lasers (FELs), new methods have been developed to extend capabilities at short wavelengths beyond Self-Amplified Spontaneous Emission (SASE). In particular, seeding of a FEL allows for temporal control of the radiation pulse and increases the peak brightness by orders of magnitude. Most recently, Gennady Stupakov and colleagues at SLAC proposed a new technique: Echo-Enabled Harmonic Generation (EEHG). Here a laser microbunches the beam in an undulator and the beam is sheared in a chicane. This process is repeated with a second laser, undulator and chicane. The interplay between these allows a seeding of the X-ray laser up to the 100th harmonic of the first laser. After introducing the physics of FELs and the EEHG seeding technique, we describe contributions to the experimental effort. We will present detailed studies of the experiment including the choice of parameters and their optimization, the emittance effect, spontaneous emission in the undulators, the second laser phase effect, and measurements of the jitter between RF stations. Finally, the status and preliminary results of the Echo-7 experiment will be outlined.

  2. Two-body photodisintegration of the deutron at high energy: Experiment NE17 at SLAC

    SciTech Connect

    Geesaman, D.F.; Jackson, H.E.; Hansen, J.O.

    1995-08-01

    Experiment NE17 was granted three days of beam time during the last NPAS run at SLAC. During that time, the cross section data for the {gamma}d {yields} pn reaction were extended up to 2.8 GeV at {theta}{sub cm} = 90{degrees} and up to 4.2 GeV at {theta}{sub cm} = 37{degrees}. Data were also taken at {theta}{sub cm} = 37{degrees} 53{degrees}, and 90{degrees} at E{gamma} = 1.6 GeV so that a complete angular distribution would be available at this energy where an Enhancement at a large angle (143{degrees}) was found during experiment NE8. The results indicate the surprising feature that the cross sections at 90{degrees} and 53{degrees} follow the quark counting rule prediction, while those at 37{degrees} do not. Perhaps this indicates that p{sub T}{sup 2} is a controlling variable in the approach to asymptotic scaling. A manuscript was accepted for publication.

  3. The physics program of a high-luminosity asymmetric B Factory at SLAC

    SciTech Connect

    Not Available

    1989-10-01

    A high-luminosity asymmetric energy B Factory, proposed as an upgrade to the PEP storage ring at SLAC, provides the best opportunity to study CP violation as a means of testing the consistency of the Standard Model. If the phenomenon of CP violation is explained by the Standard Model simply through the non-zero angles and phase of the Kobayashi-Maskawa matrix, then there are precise relations between the K-M parameters and the various measurable CP-violating asymmetries in B meson decay. Should these consistency relations fail, the origin of CP violation must lie outside the Standard Model framework. Our measurements would then lead to the first experiment-driven extensions of the Standard Model. The B Factory will also carry out a varied, high-quality program of studies of other aspects of the physics of b quarks, as well as high-precision measurements in {tau} and charm physics. We describe a detailed series of measurements to be carried out in the first few years at a peak luminosity of 3 {times} 10{sup 33} cm{sup -2}sec{sup -1}, the initial luminosity goal of the B Factory, as well as the program accessible to a larger data sample.

  4. The Physics Program of a High-Luminosity Asymmetric B Factory at SLAC

    SciTech Connect

    Eisner, A.; Mandelkern, M.; Morrison, R.; Witherell, M.; Burchat, P.; Kent, J.; Erbacher, R.; Vernon, W.; Eigen, G.; Hitlin, D.; Porter, F.; Weinstein, A.; Wisniewski, W.; Wagner, S.; Franzini, P.; Tuts, M.; Averill, D.; Snyder, A.; Goldhaber, G.; Oddone, P.; Roe, N.; Ronan, M.; Spahn, M.; MacFarlane, D.; Bartelt, J.; Bloom, E.; Bulos, F.; Cords, D.; Dib, C.; Dorfan, J.; Dunietz, I.; Gilman, F.; Godfrey, G.; Hyer, T.; Jensen, G.; Leith, D.; Marsiske, H.; Nir, Y.; Lee-Franzini, J.

    1989-10-01

    A high-luminosity asymmetric energy B Factory, proposed as an upgrade to the PEP storage ring at SLAC, provides the best opportunity to study CP violation as a means of testing the consistency of the Standard Model. If the phenomenon of CP violation is xplained by the Standard Model simply through the non-zero angles and phase of the Kobayashi-Maskawa matrix, then there are precise relations between the K-M parameters and the various measurable CP-violating asymmetries in B meson decay. Should these onsistency relations fail, the origin of CP violation must lie outside the Standard Model framework. Our measurements would then lead to the first experiment-driven extensions of the Standard Model. The B Factory will also carry out a varied, high-quality program of studies f other aspects of the physics of b quarks, as well as high-precision measurements in r and charm physics. We describe a detailed series of measurements to be carried out in the first few years at a peak luminosity of 3 x 10{sup 33} cm{sup -2}sec{sup -1}, the initial luminosity goal of the B Factory, as well as the program accessible to a larger data sample.

  5. Beam Stabilization in the SLAC A-line Using a Skew Quadrupole

    SciTech Connect

    Woodley, Mark D

    2002-09-27

    The E158 experiment at SLAC is a precision measurement of the left-right asymmetry in Moeller scattering at low Q{sup 2} utilizing a high-current long-pulse polarized electron beam scattering off unpolarized electrons in a liquid hydrogen target [1]. Tolerances on beam size and position/angle stability for E158 are extremely tight, but the electron beam is subject to intensity jitter, dispersion, and wakefield effects in the linac which tend to make it unstable. Horizontal emittance growth due to synchrotron radiation in the transport line from the linac to the target (''A-line'') reduces the sensitivity of the horizontal beam parameters at the target to incoming changes, but instability in the vertical plane was observed during the E158 pilot run. A skew quadrupole recently installed in the A-line 90 m upstream of the target has been used to couple the projected transverse emittances, increasing the vertical emittance of the beam and thereby reducing its sensitivity to incoming changes. Simulations of the performance of this skew quadrupole, along with measured beam data with and without the skew quadrupole, will be presented.

  6. Performance of the beam position monitor system for the SLAC PEP-II B factory

    SciTech Connect

    Johnson, Ronald G.; Smith, Stephen R.; Aiello, G. Roberto

    1998-12-10

    The beam position monitor (BPM) system for the SLAC PEP-II B Factory was designed to measure the positions of single-bunch single-turn to multibunch multi-turn beams in both rings of the facility. Each BPM is based on four button-style pickups. At most locations the buttons are connected to provide single-axis information (x only or y only). Operating at a harmonic (952 MHz) of the bunch spacing, the BPM system combines broadband and narrowband capabilities and provides data at a high rate. The active electronics system is multiplexed for signals from the high-energy ring (HER) and low-energy ring (LER). The system will be briefly described; however, the main purpose of the present paper is to present operational results. The BPM system operated successfully during commissioning of the HER (primarily) and the LER over the past year. Results to be presented include on-line calibration, single-bunch single-turn resolution (<100 {mu}m), and multibunch multi-turn resolution (<3 {mu}m), multiplexing, and absolute calibration. Thus far, the system has met or exceeded all the requirements that have been tested. The remaining requirements will be tested when both rings are completed and commissioned this summer. In addition, typical results of beam physics studies relying on the BPM system will be presented.

  7. Performance of the beam position monitor system for the SLAC PEP-II {ital B} factory

    SciTech Connect

    Johnson, R.G.; Smith, S.R.; Aiello, G.R.

    1998-12-01

    The beam position monitor (BPM) system for the SLAC PEP-II {ital B} Factory was designed to measure the positions of single-bunch single-turn to multibunch multi-turn beams in both rings of the facility. Each BPM is based on four button-style pickups. At most locations the buttons are connected to provide single-axis information ({ital x} only or {ital y} only). Operating at a harmonic (952 MHz) of the bunch spacing, the BPM system combines broadband and narrowband capabilities and provides data at a high rate. The active electronics system is multiplexed for signals from the high-energy ring (HER) and low-energy ring (LER). The system will be briefly described; however, the main purpose of the present paper is to present operational results. The BPM system operated successfully during commissioning of the HER (primarily) and the LER over the past year. Results to be presented include on-line calibration, single-bunch single-turn resolution ({lt}100 {mu}m), and multibunch multi-turn resolution ({lt}3 {mu}m), multiplexing, and absolute calibration. Thus far, the system has met or exceeded all the requirements that have been tested. The remaining requirements will be tested when both rings are completed and commissioned this summer. In addition, typical results of beam physics studies relying on the BPM system will be presented. {copyright} {ital 1998 American Institute of Physics.}

  8. Lattice Design of PEP-X as a Light Source Machine at SLAC

    SciTech Connect

    Wang, Min-Huey; Cai, Yunhai; Hettel, Robert; Nosochkov, Yuri; /SLAC

    2008-07-03

    SLAC is studying an option of building a high brightness synchrotron light source machine, PEP-X, in the existing PEP-II tunnel [1]. The new machine will replace the PEPII High Energy Ring (HER) with the goal of achieving an ultra low emittance of {approx} 0.1 nm-rad at 4.5 GeV. The PEPX will utilize the same layout as in the PEP-II with 6 arcs and 6 long straight sections. The existing RF and injection systems will be re-used. The two HER FODO arcs will be replaced with the DBA arcs providing 30 dispersion free 4.26 m sections for magnetic undulators. The other four arcs will be replaced with the TME lattice for attaining the low emittance. Finally, a 89.3 m long damping wiggler with 10 cm period and 1.5 T maximum magnetic field will be installed in a long straight section to reduce the natural emittance to 0.094 nm-rad. The PEP-X dynamic aperture was studied and found sufficient for a vertical injection.

  9. A combined analysis of SLAC experiments on deep inelastic e-p and e-d scattering

    SciTech Connect

    Whitlow, L.W.; Bodek, A.; deBarbaro, P.; Dasu, S.; Harada, H.; Krasny, M.W.; Lang, K.; Riordan, E.M.; Rock, S.; Arnold, R.; Benton, D.; Bosted, P.; Button-Shafer, J.; deChambrier, G.; Clogher, L.; Lung, A.; Szalata, Z.M.; Alster, J.; Debebe, B.; Hicks, R.; Dietrich, F.; Van Bibber, K.; Filippone, B.; Jourdan, J.; Milner, R.; McKeown, R.; Potterveld, D.; Walker, R.C.; Gearhart, R.; Para, A.

    1989-08-01

    We report recent work on the extraction of R = {sigma}{sub L}/{sigma}{sub T} and the structure function F{sub 2} over a large kinematic range, which is based on a reanalysis of deep inelastic {var_epsilon} {minus} p and {var_epsilon} {minus} d scattering cross sections measured at SLAC between 1970 and 1985. All these data were corrected for radiative effects using improved versions of external and internal radiative correction procedures. The data from seven individual experiments were normalized to those from the recent high-precision SLAC experiment E140. We find that R{sub p} = R{sub d}, as expected in QCD. The value of R is higher than predicted by QCD even when target-mass effects are included. This difference indicates that additional dynamical higher-twist effects may be present. The structure functions F{sub 2}p and F{sub 2}d were also extracted from the full data sets of normalized cross sections using an empirical fit to R. These structure functions were then compared with data from the CERN muon scattering experiments BCDMS and EMC. We find that our data are consistent with the EMC data, if the latter are multiplied by a normalization factor of 1.07. No single, uniform normalization factor can be applied to the BCDMS data that will bring them into agreement with the SLAC data in the region of overlap.

  10. A combined analysis of SLAC experiments on deep inelastic e-p and e-d scattering

    SciTech Connect

    Whitlow, L.W. ); Bodek, A.; deBarbaro, P.; Dasu, S.; Harada, H.; Krasny, M.W.; Lang, K.; Riordan, E.M. ); Rock, S.; Arnold, R.; Benton, D.; Bosted, P.; Button-Shafer, J.; deChambrier, G.; Clogher, L.; Lung, A.; Szalata, Z.M. ); Alster, J. ); Debebe, B.; Hicks, R. (Massach

    1989-08-01

    We report recent work on the extraction of R = {sigma}{sub L}/{sigma}{sub T} and the structure function F{sub 2} over a large kinematic range, which is based on a reanalysis of deep inelastic {var epsilon} {minus} p and {var epsilon} {minus} d scattering cross sections measured at SLAC between 1970 and 1985. All these data were corrected for radiative effects using improved versions of external and internal radiative correction procedures. The data from seven individual experiments were normalized to those from the recent high-precision SLAC experiment E140. We find that R{sub p} = R{sub d}, as expected in QCD. The value of R is higher than predicted by QCD even when target-mass effects are included. This difference indicates that additional dynamical higher-twist effects may be present. The structure functions F{sub 2}p and F{sub 2}d were also extracted from the full data sets of normalized cross sections using an empirical fit to R. These structure functions were then compared with data from the CERN muon scattering experiments BCDMS and EMC. We find that our data are consistent with the EMC data, if the latter are multiplied by a normalization factor of 1.07. No single, uniform normalization factor can be applied to the BCDMS data that will bring them into agreement with the SLAC data in the region of overlap.

  11. SPEAR3 Accelerator Physics Update

    SciTech Connect

    Safranek, James A.; Corbett, W.Jeff; Gierman, S.; Hettel, R.O.; Huang, X.; Nosochkov, Yuri; Sebek, Jim; Terebilo, Andrei; /SLAC

    2007-11-02

    The SPEAR3 storage ring at Stanford Synchrotron Radiation Laboratory has been delivering photon beams for three years. We will give an overview of recent and ongoing accelerator physics activities, including 500 mA fills, work toward top-off injection, long-term orbit stability characterization and improvement, fast orbit feedback, new chicane optics, low alpha optics & short bunches, low emittance optics, and MATLAB software. The accelerator physics group has a strong program to characterize and improve SPEAR3 performance

  12. Acceleration Studies

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.

    1993-01-01

    Work to support the NASA MSFC Acceleration Characterization and Analysis Project (ACAP) was performed. Four tasks (analysis development, analysis research, analysis documentation, and acceleration analysis) were addressed by parallel projects. Work concentrated on preparation for and implementation of near real-time SAMS data analysis during the USMP-1 mission. User support documents and case specific software documentation and tutorials were developed. Information and results were presented to microgravity users. ACAP computer facilities need to be fully implemented and networked, data resources must be cataloged and accessible, future microgravity missions must be coordinated, and continued Orbiter characterization is necessary.

  13. The Transmembrane Region of Guard Cell SLAC1 Channels Perceives CO2 Signals via an ABA-Independent Pathway in Arabidopsis.

    PubMed

    Yamamoto, Yoshiko; Negi, Juntaro; Wang, Cun; Isogai, Yasuhiro; Schroeder, Julian I; Iba, Koh

    2016-02-01

    The guard cell S-type anion channel, SLOW ANION CHANNEL1 (SLAC1), a key component in the control of stomatal movements, is activated in response to CO2 and abscisic acid (ABA). Several amino acids existing in the N-terminal region of SLAC1 are involved in regulating its activity via phosphorylation in the ABA response. However, little is known about sites involved in CO2 signal perception. To dissect sites that are necessary for the stomatal CO2 response, we performed slac1 complementation experiments using transgenic plants expressing truncated SLAC1 proteins. Measurements of gas exchange and stomatal apertures in the truncated transgenic lines in response to CO2 and ABA revealed that sites involved in the stomatal CO2 response exist in the transmembrane region and do not require the SLAC1 N and C termini. CO2 and ABA regulation of S-type anion channel activity in guard cells of the transgenic lines confirmed these results. In vivo site-directed mutagenesis experiments targeted to amino acids within the transmembrane region of SLAC1 raise the possibility that two tyrosine residues exposed on the membrane are involved in the stomatal CO2 response. PMID:26764376

  14. The Stanford Linear Accelerator Center pulsed x-ray facility.

    PubMed

    Ipe, N E; McCall, R C; Baker, E D

    1987-04-01

    The Stanford Linear Accelerator Center (SLAC) operates a high-energy (up to 33 GeV) linear accelerator delivering pulses up to a few microseconds wide. The pulsed nature of the electron beam creates problems in the detection and measurement of radiation both from the accelerator beam and the klystrons that provide the radio-frequency power for the accelerator. Hence, a pulsed x-ray facility has been built at SLAC mainly for testing the response of different radiation detection instruments to pulsed radiation fields. The x-ray tube consists of an electron gun with a control grid. This provides a stream of pulsed electrons that can be accelerated towards a confined target window. The window consists of Al 0.051 cm (20 mils) thick, plated on the vacuum side with a layer of Au 0.0006 cm (1/4 mil) thick. The frequency of electron pulses can be varied by an internal pulser from 60 to 360 pulses per second with pulse widths of 360 ns to 5 microseconds. The pulse amplitude can be varied over a wide range of currents. An external pulser can be used to obtain other frequencies or special pulse shapes. The voltage across the gun can be varied from 0 to 100 kV. The maximum absorbed dose rate obtained at 6.35 cm below the target window as measured by an ionization chamber is 258 Gy/h. The major part of the x-ray tube is enclosed in a large walk-in cabinet made of 1.9-cm-thick (3/4-inch-thick) plywood and lined with 0.32-cm-thick (1/8-inch-thick) Pb to make a very versatile facility. PMID:3570789

  15. Imaging using accelerated heavy ions

    SciTech Connect

    Chu, W.T.

    1982-05-01

    Several methods for imaging using accelerated heavy ion beams are being investigated at Lawrence Berkeley Laboratory. Using the HILAC (Heavy-Ion Linear Accelerator) as an injector, the Bevalac can accelerate fully stripped atomic nuclei from carbon (Z = 6) to krypton (Z = 34), and partly stripped ions up to uranium (Z = 92). Radiographic studies to date have been conducted with helium (from 184-inch cyclotron), carbon, oxygen, and neon beams. Useful ranges in tissue of 40 cm or more are available. To investigate the potential of heavy-ion projection radiography and computed tomography (CT), several methods and instrumentation have been studied.

  16. Plasma accelerator

    DOEpatents

    Wang, Zhehui; Barnes, Cris W.

    2002-01-01

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  17. Accelerated Achievement

    ERIC Educational Resources Information Center

    Ford, William J.

    2010-01-01

    This article focuses on the accelerated associate degree program at Ivy Tech Community College (Indiana) in which low-income students will receive an associate degree in one year. The three-year pilot program is funded by a $2.3 million grant from the Lumina Foundation for Education in Indianapolis and a $270,000 grant from the Indiana Commission…

  18. ACCELERATION INTEGRATOR

    DOEpatents

    Pope, K.E.

    1958-01-01

    This patent relates to an improved acceleration integrator and more particularly to apparatus of this nature which is gyrostabilized. The device may be used to sense the attainment by an airborne vehicle of a predetermined velocitv or distance along a given vector path. In its broad aspects, the acceleration integrator utilizes a magnetized element rotatable driven by a synchronous motor and having a cylin drical flux gap and a restrained eddy- current drag cap deposed to move into the gap. The angular velocity imparted to the rotatable cap shaft is transmitted in a positive manner to the magnetized element through a servo feedback loop. The resultant angular velocity of tae cap is proportional to the acceleration of the housing in this manner and means may be used to measure the velocity and operate switches at a pre-set magnitude. To make the above-described dcvice sensitive to acceleration in only one direction the magnetized element forms the spinning inertia element of a free gyroscope, and the outer housing functions as a gimbal of a gyroscope.

  19. Particle acceleration

    NASA Technical Reports Server (NTRS)

    Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.

    1986-01-01

    Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.

  20. UCLA Neptune Facility for Advanced Accelerator Studies

    SciTech Connect

    Tochitsky, Sergei Ya.; Clayton, Christopher E.; Marsh, Kenneth A.; Joshi, Chandrashekhar; Rosenzweig, James B.; Pellegrini, Claudio

    2004-12-07

    The Neptune Laboratory at UCLA is being used for exploring concepts useful for advanced accelerators. This facility hosts a TW-class CO2 laser system and a high-brightness photoinjector producing a 14 MeV electron beam. The goal for the laboratory is to carry out experiments on high-gradient acceleration of externally injected electrons in both laser-driven relativistic plasma waves and EM laser field in vacuum. Experiments on plasma beat-wave acceleration using a prebunched electron beam, a high-energy gain 10-{mu}m inverse free electron laser accelerator, longitudinal electron beam shaping and laser based light-sources are planned.

  1. Design of the SLAC RCE Platform: A General Purpose ATCA Based Data Acquisition System

    SciTech Connect

    Herbst, R.; Claus, R.; Freytag, M.; Haller, G.; Huffer, M.; Maldonado, S.; Nishimura, K.; O'Grady, C.; Panetta, J.; Perazzo, A.; Reese, B.; Ruckman, L.; Thayer, J. G.; Weaver, M.

    2015-01-23

    The SLAC RCE platform is a general purpose clustered data acquisition system implemented on a custom ATCA compliant blade, called the Cluster On Board (COB). The core of the system is the Reconfigurable Cluster Element (RCE), which is a system-on-chip design based upon the Xilinx Zynq family of FPGAs, mounted on custom COB daughter-boards. The Zynq architecture couples a dual core ARM Cortex A9 based processor with a high performance 28nm FPGA. The RCE has 12 external general purpose bi-directional high speed links, each supporting serial rates of up to 12Gbps. 8 RCE nodes are included on a COB, each with a 10Gbps connection to an on-board 24-port Ethernet switch integrated circuit. The COB is designed to be used with a standard full-mesh ATCA backplane allowing multiple RCE nodes to be tightly interconnected with minimal interconnect latency. Multiple shelves can be clustered using the front panel 10-gbps connections. The COB also supports local and inter-blade timing and trigger distribution. An experiment specific Rear Transition Module adapts the 96 high speed serial links to specific experiments and allows an experiment-specific timing and busy feedback connection. This coupling of processors with a high performance FPGA fabric in a low latency, multiple node cluster allows high speed data processing that can be easily adapted to any physics experiment. RTEMS and Linux are both ported to the module. The RCE has been used or is the baseline for several current and proposed experiments (LCLS, HPS, LSST, ATLAS-CSC, LBNE, DarkSide, ILC-SiD, etc).

  2. Hybrid Paper/Electronic Archival Collecting, Processing, and Reference: A View from SLAC

    SciTech Connect

    Deken, Jean M.; /SLAC

    2008-05-23

    Real-time archiving of mixed paper and digital collections presents challenges not encountered in the primarily paper environment. A few recent examples from the archives of the Stanford Linear Accelerator Center highlight obstacles encountered, and attempted and contemplated solutions.

  3. Acceleration Environment of the International Space Station

    NASA Technical Reports Server (NTRS)

    McPherson, Kevin; Kelly, Eric; Keller, Jennifer

    2009-01-01

    Measurement of the microgravity acceleration environment on the International Space Station has been accomplished by two accelerometer systems since 2001. The Microgravity Acceleration Measurement System records the quasi-steady microgravity environment, including the influences of aerodynamic drag, vehicle rotation, and venting effects. Measurement of the vibratory/transient regime, comprised of vehicle, crew, and equipment disturbances, has been accomplished by the Space Acceleration Measurement System-II. Until the arrival of the Columbus Orbital Facility and the Japanese Experiment Module, the location of these sensors, and therefore, the measurement of the microgravity acceleration environment, has been limited to within the United States Laboratory. Japanese Aerospace Exploration Agency has developed a vibratory acceleration measurement system called the Microgravity Measurement Apparatus which will be deployed within the Japanese Experiment Module to make distributed measurements of the Japanese Experiment Module's vibratory acceleration environment. Two Space Acceleration Measurement System sensors from the United States Laboratory will be re-deployed to support vibratory acceleration data measurement within the Columbus Orbital Facility. The additional measurement opportunities resulting from the arrival of these new laboratories allows Principal Investigators with facilities located in these International Space Station research laboratories to obtain microgravity acceleration data in support of their sensitive experiments. The Principal Investigator Microgravity Services project, at NASA Glenn Research Center, in Cleveland, Ohio, has supported acceleration measurement systems and the microgravity scientific community through the processing, characterization, distribution, and archival of the microgravity acceleration data obtained from the International Space Station acceleration measurement systems. This paper summarizes the PIMS capabilities available

  4. Finite element analyses of a linear-accelerator electron gun

    SciTech Connect

    Iqbal, M. E-mail: muniqbal@ihep.ac.cn; Wasy, A.; Islam, G. U.; Zhou, Z.

    2014-02-15

    Thermo-structural analyses of the Beijing Electron-Positron Collider (BEPCII) linear-accelerator, electron gun, were performed for the gun operating with the cathode at 1000 °C. The gun was modeled in computer aided three-dimensional interactive application for finite element analyses through ANSYS workbench. This was followed by simulations using the SLAC electron beam trajectory program EGUN for beam optics analyses. The simulations were compared with experimental results of the assembly to verify its beam parameters under the same boundary conditions. Simulation and test results were found to be in good agreement and hence confirmed the design parameters under the defined operating temperature. The gun is operating continuously since commissioning without any thermal induced failures for the BEPCII linear accelerator.

  5. Advances in Parallel Electromagnetic Codes for Accelerator Science and Development

    SciTech Connect

    Ko, Kwok; Candel, Arno; Ge, Lixin; Kabel, Andreas; Lee, Rich; Li, Zenghai; Ng, Cho; Rawat, Vineet; Schussman, Greg; Xiao, Liling; /SLAC

    2011-02-07

    Over a decade of concerted effort in code development for accelerator applications has resulted in a new set of electromagnetic codes which are based on higher-order finite elements for superior geometry fidelity and better solution accuracy. SLAC's ACE3P code suite is designed to harness the power of massively parallel computers to tackle large complex problems with the increased memory and solve them at greater speed. The US DOE supports the computational science R&D under the SciDAC project to improve the scalability of ACE3P, and provides the high performance computing resources needed for the applications. This paper summarizes the advances in the ACE3P set of codes, explains the capabilities of the modules, and presents results from selected applications covering a range of problems in accelerator science and development important to the Office of Science.

  6. Compact accelerator

    DOEpatents

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    2007-02-06

    A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

  7. BICEP's acceleration

    SciTech Connect

    Contaldi, Carlo R.

    2014-10-01

    The recent Bicep2 [1] detection of, what is claimed to be primordial B-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential V(φ) for the first time — if a single, scalar inflaton is assumed to be driving the acceleration. We carry out a Monte Carlo exploration of inflationary trajectories given the current data. Using this method we obtain a posterior distribution of possible acceleration profiles ε(N) as a function of e-fold N and derived posterior distributions of the primordial power spectrum P(k) and potential V(φ). We find that the Bicep2 result, in combination with Planck measurements of total intensity Cosmic Microwave Background (CMB) anisotropies, induces a significant feature in the scalar primordial spectrum at scales k∼ 10{sup -3} Mpc {sup -1}. This is in agreement with a previous detection of a suppression in the scalar power [2].

  8. Reconstitution of CO2 Regulation of SLAC1 Anion Channel and Function of CO2-Permeable PIP2;1 Aquaporin as CARBONIC ANHYDRASE4 Interactor.

    PubMed

    Wang, Cun; Hu, Honghong; Qin, Xue; Zeise, Brian; Xu, Danyun; Rappel, Wouter-Jan; Boron, Walter F; Schroeder, Julian I

    2016-02-01

    Dark respiration causes an increase in leaf CO2 concentration (Ci), and the continuing increases in atmospheric [CO2] further increases Ci. Elevated leaf CO2 concentration causes stomatal pores to close. Here, we demonstrate that high intracellular CO2/HCO3 (-) enhances currents mediated by the Arabidopsis thaliana guard cell S-type anion channel SLAC1 upon coexpression of any one of the Arabidopsis protein kinases OST1, CPK6, or CPK23 in Xenopus laevis oocytes. Split-ubiquitin screening identified the PIP2;1 aquaporin as an interactor of the βCA4 carbonic anhydrase, which was confirmed in split luciferase, bimolecular fluorescence complementation, and coimmunoprecipitation experiments. PIP2;1 exhibited CO2 permeability. Mutation of PIP2;1 in planta alone was insufficient to impair CO2- and abscisic acid-induced stomatal closing, likely due to redundancy. Interestingly, coexpression of βCA4 and PIP2;1 with OST1-SLAC1 or CPK6/23-SLAC1 in oocytes enabled extracellular CO2 enhancement of SLAC1 anion channel activity. An inactive PIP2;1 point mutation was identified that abrogated water and CO2 permeability and extracellular CO2 regulation of SLAC1 activity. These findings identify the CO2-permeable PIP2;1 as key interactor of βCA4 and demonstrate functional reconstitution of extracellular CO2 signaling to ion channel regulation upon coexpression of PIP2;1, βCA4, SLAC1, and protein kinases. These data further implicate SLAC1 as a bicarbonate-responsive protein contributing to CO2 regulation of S-type anion channels. PMID:26764375

  9. Advanced concepts for acceleration

    SciTech Connect

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations. (LEW)

  10. Strategies for mitigating the ionization-induced beam head erosion problem in an electron-beam-driven plasma wakefield accelerator

    NASA Astrophysics Data System (ADS)

    An, W.; Zhou, M.; Vafaei-Najafabadi, N.; Marsh, K. A.; Clayton, C. E.; Joshi, C.; Mori, W. B.; Lu, W.; Adli, E.; Corde, S.; Litos, M.; Li, S.; Gessner, S.; Frederico, J.; Hogan, M. J.; Walz, D.; England, J.; Delahaye, J. P.; Muggli, P.

    2013-10-01

    Strategies for mitigating ionization-induced beam head erosion in an electron-beam-driven plasma wakefield accelerator (PWFA) are explored when the plasma and the wake are both formed by the transverse electric field of the beam itself. Beam head erosion can occur in a preformed plasma because of a lack of focusing force from the wake at the rising edge (head) of the beam due to the finite inertia of the electrons. When the plasma is produced by field ionization from the space charge field of the beam, the head erosion is significantly exacerbated due to the gradual recession (in the beam frame) of the 100% ionization contour. Beam particles in front of the ionization front cannot be focused (guided) causing them to expand as in vacuum. When they expand, the location of the ionization front recedes such that even more beam particles are completely unguided. Eventually this process terminates the wake formation prematurely, i.e., well before the beam is depleted of its energy. Ionization-induced head erosion can be mitigated by controlling the beam parameters (emittance, charge, and energy) and/or the plasma conditions. In this paper we explore how the latter can be optimized so as to extend the beam propagation distance and thereby increase the energy gain. In particular we show that, by using a combination of the alkali atoms of the lowest practical ionization potential (Cs) for plasma formation and a precursor laser pulse to generate a narrow plasma filament in front of the beam, the head erosion rate can be dramatically reduced. Simulation results show that in the upcoming “two-bunch PWFA experiments” on the FACET facility at SLAC national accelerator laboratory the energy gain of the trailing beam can be up to 10 times larger for the given parameters when employing these techniques. Comparison of the effect of beam head erosion in preformed and ionization produced plasmas is also presented.

  11. Accelerators and the Accelerator Community

    SciTech Connect

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  12. Independent Study Unit on Accelerated Reference Frames

    ERIC Educational Resources Information Center

    Poultney, S. K.

    1973-01-01

    Presents a list of topics, research areas, references, and laboratory equipment which is prepared to facilitate general-science students' understanding of physics aspects in accelerated reference frames after their study of circular motion and Galilean relativity in mechanics. (CC)

  13. The Echo Sounding Rocket Payloads as a Laboratory in Space to Study the Dynamics of the Natural Aurora Acceleration Mechanism and Other Important Contributions John Winckler has Made to the Field

    NASA Astrophysics Data System (ADS)

    Arnoldy, R. L.

    2001-12-01

    It is with great honor that I have the opportunity to talk about some of the contributions Prof. John Winckler has made to space science and auroral physics in particular. John's interest in the aurora began on the first day of the IGY during a balloon flight designed to be the start of a campaign to do a latitudinal survey of the cosmic ray cut-off during the IGY. The detectors of this flight unexpectedly measured 50-100 keV x-rays produced by auroral electrons bombarding the top of the atmosphere. After retiring from teaching, John's interest in the dynamics of low-latitude aurora came full circle from its starting point during that first day of the IGY almost thirty years earlier. With ground photometers, cameras and stereoscopic TV, he made extensive observations of the pulsation phase of auroras during the peak of solar cycle 22. Although pulsating aurora had been studied for decades at auroral zone latitudes, John's work at sub-auroral latitudes discovered new phenomena and made observations of known phenomena in greater detail. The intent of this talk is primarily to consider Winckler's pioneering work with electron beam injections into the magnetosphere from sounding rockets. The motivation for this work initially was to map auroral field lines and to study large scale magnetospheric electric fields. The aspect of the work that I was most intimately involved in was the mechanism of neutralizing the rocket after it had injected nearly a coulomb of negative charge into space. It was initially argued that the beams would become unstable and therefore be destroyed and useless as probes of the magnetosphere. This was not the case, hence the neutralization mechanism became a significant study of the program. Although not realized at the time, it turns out that the beam injections at rocket altitude in essence became a laboratory in space in which many of the features of the aurora itself were reproduced. It is accepted that the electrons of a discrete aurora are

  14. Increased leaf photosynthesis caused by elevated stomatal conductance in a rice mutant deficient in SLAC1, a guard cell anion channel protein

    PubMed Central

    Kusumi, Kensuke

    2012-01-01

    In rice (Oryza sativa L.), leaf photosynthesis is known to be highly correlated with stomatal conductance; however, it remains unclear whether stomatal conductance dominantly limits the photosynthetic rate. SLAC1 is a stomatal anion channel protein controlling stomatal closure in response to environmental [CO2]. In order to examine stomatal limitations to photosynthesis, a SLAC1-deficient mutant of rice was isolated and characterized. A TILLING screen of N-methyl-N-nitrosourea-derived mutant lines was conducted for the rice SLAC1 orthologue gene Os04g0674700, and four mutant lines containing mutations within the open reading frame were obtained. A second screen using an infrared thermography camera revealed that one of the mutants, named slac1, had a constitutive low leaf temperature phenotype. Measurement of leaf gas exchange showed that slac1 plants grown in the greenhouse had significantly higher stomatal conductance (g s), rates of photosynthesis (A), and ratios of internal [CO2] to ambient [CO2] (C i/C a) compared with wild-type plants, whereas there was no significant difference in the response of photosynthesis to internal [CO2] (A/C i curves). These observations demonstrate that in well-watered conditions, stomatal conductance is a major determinant of photosynthetic rate in rice. PMID:22915747

  15. Linear accelerator for tritium production

    SciTech Connect

    Garnett, R.W.; Billen, J.H.; Chan, K.C.; Genzlinger, R.; Gray, E.R.; Nath, S.; Rusnak, B.; Schrage, D.L.; Stovall, J.E.; Takeda, H.; Wood, R.; Wangler, T.P.; Young, L.M.

    1996-06-01

    For many years now, Los Alamos National Laboratory has been working to develop a conceptual design of a facility for accelerator production of tritium (APT). The APT accelerator will produce high energy protons which will bombard a heavy metal target, resulting in the production of large numbers of spallation neutrons. These neutrons will be captured by a low-{ital Z} target to produce tritium. This paper describes the latest design of a room-temperature, 1.0 GeV, 100 mA, cw proton accelerator for tritium production. The potential advantages of using superconducting cavities in the high-energy section of the linac are also discussed and a comparison is made with the baseline room-temperature accelerator. {copyright} {ital 1996 American Institute of Physics.}

  16. Measurement of Coriolis Acceleration with a Smartphone

    ERIC Educational Resources Information Center

    Shaku, Asif; Kraft, Jakob

    2016-01-01

    Undergraduate physics laboratories seldom have experiments that measure the Coriolis acceleration. This has traditionally been the case owing to the inherent complexities of making such measurements. Articles on the experimental determination of the Coriolis acceleration are few and far between in the physics literature. However, because modern…

  17. Accelerator mass spectrometry with heavy ions

    NASA Astrophysics Data System (ADS)

    Haberstock, Günther; Heinzl, Johann; Korschinek, Gunther; Morinaga, Haruhiko; Nolte, Eckehart; Ratzinger, Ulrich; Kato, Kazuo; Wolf, Manfred

    1986-11-01

    Accelerator mass spectrometry measurements with fully stripped 36Cl ions have been performed at the Munich accelerator laboratory in order to date groundwaters and palaeontological samples, to study anthropogenic 36Cl produced through nuclear tests and to determine the fast neutron flux of the Hiroshima A-bomb.

  18. 25 MV tandem accelerator at Oak Ridge

    SciTech Connect

    Jones, C.M.

    1980-01-01

    A new heavy-ion accelerator facility is under construction at the Oak Ridge National Laboratory. A brief description of the scope and status of this project is presented with emphasis on the first operational experience with the 25 MV tandem accelerator.

  19. Numerical Verification of the Power Transfer and Wakefield Coupling in the Clic Two-Beam Accelerator

    SciTech Connect

    Candel, Arno; Li, Z.; Ng, C.; Rawat, V.; Schussman, G.; Ko, K.; Syratchev, I.; Grudiev, A.; Wuensch, W.; /CERN

    2011-08-19

    The Compact Linear Collider (CLIC) provides a path to a multi-TeV accelerator to explore the energy frontier of High Energy Physics. Its two-beam accelerator (TBA) concept envisions complex 3D structures, which must be modeled to high accuracy so that simulation results can be directly used to prepare CAD drawings for machining. The required simulations include not only the fundamental mode properties of the accelerating structures but also the Power Extraction and Transfer Structure (PETS), as well as the coupling between the two systems. Time-domain simulations will be performed to understand pulse formation, wakefield damping, fundamental power transfer and wakefield coupling in these structures. Applying SLAC's parallel finite element code suite, these large-scale problems will be solved on some of the largest supercomputers available. The results will help to identify potential issues and provide new insights on the design, leading to further improvements on the novel two-beam accelerator scheme.

  20. Inverse Free Electron Laser accelerator

    NASA Astrophysics Data System (ADS)

    Fisher, A.; Gallardo, J.; Vansteenbergen, A.; Sandweiss, J.

    1992-09-01

    The study of the INVERSE FREE ELECTRON LASER, as a potential mode of electron acceleration, is being pursued at Brookhaven National Laboratory. Recent studies have focussed on the development of a low energy, high gradient, multi stage linear accelerator. The elementary ingredients for the IFEL interaction are the 50 MeV Linac e(-) beam and the 10(exp 11) Watt CO2 laser beam of BNL's Accelerator Test Facility (ATF), Center for Accelerator Physics (CAP) and a wiggler. The latter element is designed as a fast excitation unit making use of alternating stacks of Vanadium Permendur (VaP) ferromagnetic laminations, periodically interspersed with conductive, nonmagnetic laminations, which act as eddy current induced field reflectors. Wiggler parameters and field distribution data will be presented for a prototype wiggler in a constant period and in a approximately 1.5 percent/cm tapered period configuration. The CO2 laser beam will be transported through the IFEL interaction region by means of a low loss, dielectric coated, rectangular waveguide. Short waveguide test sections have been constructed and have been tested using a low power CW CO2 laser. Preliminary results of guide attenuation and mode selectivity will be given, together with a discussion of the optical issues for the IFEL accelerator. The IFEL design is supported by the development and use of 1D and 3D simulation programs. The results of simulation computations, including also wiggler errors, for a single module accelerator and for a multi-module accelerator will be presented.

  1. Inverse free electron laser accelerator

    NASA Astrophysics Data System (ADS)

    Fisher, A.; Gallardo, J.; Sandweiss, J.; van Steenbergen, A.

    1992-07-01

    The study of the INVERSE FREE ELECTRON LASER, as a potential mode of electron acceleration, is being pursued at Brookhaven National Laboratory. Recent studies have focussed on the development of a low energy, high gradient, multi stage linear accelerator. The elementary ingredients for the IFEL interaction are the 50 MeV Linac e- beam and the 1011 Watt CO2 laser beam of BNL's Accelerator Test Facility (ATF), Center for Accelerator Physics (CAP), and a wiggler. The latter element is designed as a fast excitation unit making use of alternating stacks of Vanadium Permendur (VaP) ferromagnetic laminations, periodically interspersed with conductive, nonmagnetic laminations, which act as eddy current induced field reflectors. Wiggler parameters and field distribution data will be presented for a prototype wiggler in a constant period and in a ≊1.5%/cm tapered period configuration. The CO2 laser beam will be transported through the IFEL interaction region by means of a low loss, dielectric coated, rectangular waveguide. Short waveguide test sections have been constructed and have been tested using a low power cw CO2 laser. Preliminary results of guide attenuation and mode selectivity will be given, together with a discussion of the optical issues for the IFEL accelerator. The IFEL design is supported by the development and use of 1D and 3D simulation programs. The results of simulation computations, including also wiggler errors, for a single module accelerator and for a multi-module accelerator will be presented.

  2. TRACKING ACCELERATOR SETTINGS.

    SciTech Connect

    D OTTAVIO,T.; FU, W.; OTTAVIO, D.P.

    2007-10-15

    Recording setting changes within an accelerator facility provides information that can be used to answer questions about when, why, and how changes were made to some accelerator system. This can be very useful during normal operations, but can also aid with security concerns and in detecting unusual software behavior. The Set History System (SHS) is a new client-server system developed at the Collider-Accelerator Department of Brookhaven National Laboratory to provide these capabilities. The SHS has been operational for over two years and currently stores about IOOK settings per day into a commercial database management system. The SHS system consists of a server written in Java, client tools written in both Java and C++, and a web interface for querying the database of setting changes. The design of the SHS focuses on performance, portability, and a minimal impact on database resources. In this paper, we present an overview of the system design along with benchmark results showing the performance and reliability of the SHS over the last year.

  3. Femtosecond laser clocked compact X-band high gradient photoinjector and accelerator for Compton scattering

    NASA Astrophysics Data System (ADS)

    Destefano, Christopher A.

    High brightness and low emittance electron beams have found application throughout a variety of scientific research. The ability to produce such beams in the MeV range has previously been restricted to National Laboratory size facilities. While these sources have been successful, the reduction in size could provide valuable access for further scientific endeavors. One such application is the production of monochromatic x-rays through Compton scattering with a high intensity laser pulse. These x-rays would be tunable from 10 keV to more than 100 keV. A compact source of synchrotron type radiation capable of installation in medical institutions would be desirable for further investigation. A combination of X-band microwave and vacuum technologies developed at the Stanford Linear Accelerator Center (SLAC) was assembled. The system uses a pair of X-band klystrons. The first provides the microwave drive power for a 5.5 cell RF gun capable of operating with an accelerating gradient of 200 MV/m. Following the RF gun is a 1.05 m linac capable of accelerating the electron bunches to over 60 MeV with an energy spread of less than 1%. Using a novel frequency selection scheme a Titantium:Sapphire femtosecond laser oscillator serves as both the master clock for the microwave components and optical seed for the following amplifiers. This insures the tabletop laser amplifiers are inherently synchronized to the RF sources. A regenerative amplifier provides the first boost in energy. Half of the output is used for producing UV light for photo injection of the RF gun. The other half is sent to a multi-pass amplifier capable of producing 100 mJ pulses compressed to 50 fs for the Compton scattering. This interaction laser is then focused inside the electron beam vacuum system. The final timing between the optical pulses and the electron beam is achieved with a physical delay line placed after the final amplifier compressor. Background Bremsstrahlung radiation due to interception of

  4. Electron Acceleration by Transient Ion Foreshock Phenomena

    NASA Astrophysics Data System (ADS)

    Wilson, L. B., III; Turner, D. L.

    2015-12-01

    Particle acceleration is a topic of considerable interest in space, laboratory, and astrophysical plasmas as it is a fundamental physical process to all areas of physics. Recent THEMIS [e.g., Turner et al., 2014] and Wind [e.g., Wilson et al., 2013] observations have found evidence for strong particle acceleration at macro- and meso-scale structures and/or pulsations called transient ion foreshock phenomena (TIFP). Ion acceleration has been extensively studied, but electron acceleration has received less attention. Electron acceleration can arise from fundamentally different processes than those affecting ions due to differences in their gyroradii. Electron acceleration is ubiquitous, occurring in the solar corona (e.g., solar flares), magnetic reconnection, at shocks, astrophysical plasmas, etc. We present new results analyzing the dependencies of electron acceleration on the properties of TIFP observed by the THEMIS spacecraft.

  5. VLHC accelerator physics

    SciTech Connect

    Michael Blaskiewicz et al.

    2001-11-01

    A six-month design study for a future high energy hadron collider was initiated by the Fermilab director in October 2000. The request was to study a staged approach where a large circumference tunnel is built that initially would house a low field ({approx}2 T) collider with center-of-mass energy greater than 30 TeV and a peak (initial) luminosity of 10{sup 34} cm{sup -2}s{sup -1}. The tunnel was to be scoped, however, to support a future upgrade to a center-of-mass energy greater than 150 TeV with a peak luminosity of 2 x 10{sup 34} cm{sup -2} sec{sup -1} using high field ({approx} 10 T) superconducting magnet technology. In a collaboration with Brookhaven National Laboratory and Lawrence Berkeley National Laboratory, a report of the Design Study was produced by Fermilab in June 2001. 1 The Design Study focused on a Stage 1, 20 x 20 TeV collider using a 2-in-1 transmission line magnet and leads to a Stage 2, 87.5 x 87.5 TeV collider using 10 T Nb{sub 3}Sn magnet technology. The article that follows is a compilation of accelerator physics designs and computational results which contributed to the Design Study. Many of the parameters found in this report evolved during the study, and thus slight differences between this text and the Design Study report can be found. The present text, however, presents the major accelerator physics issues of the Very Large Hadron Collider as examined by the Design Study collaboration and provides a basis for discussion and further studies of VLHC accelerator parameters and design philosophies.

  6. Picosecond Bunch length and Energy-z correlation measurements at SLAC's A-Line and End Station A

    SciTech Connect

    Molloy, Stephen; Emma, P.; Frisch, J.C.; Iverson, R.H.; Ross, M.; McCormick, D.J.; Ross, Marc C.; Walston, S.; Blackmore, V.; /Oxford U.

    2007-06-27

    We report on measurements of picosecond bunch lengths and the energy-z correlation of the bunch with a high energy electron test beam to the A-line and End Station A (ESA) facilities at SLAC. The bunch length and the energy-z correlation of the bunch are measured at the end of the linac using a synchrotron light monitor diagnostic at a high dispersion point in the A-line and a transverse RF deflecting cavity at the end of the linac. Measurements of the bunch length in ESA were made using high frequency diodes (up to 100 GHz) and pyroelectric detectors at a ceramic gap in the beamline. Modeling of the beam's longitudinal phase space through the linac and A-line to ESA is done using the 2-dimensional tracking program LiTrack, and LiTrack simulation results are compared with data. High frequency diode and pyroelectric detectors are planned to be used as part of a bunch length feedback system for the LCLS FEL at SLAC. The LCLS also plans precise bunch length and energy-z correlation measurements using transverse RF deflecting cavities.

  7. SLAC's polarized electron source laser system and minimization of electron beam helicity correlations for the E-158 parity violation experiment

    NASA Astrophysics Data System (ADS)

    Humensky, T. B.; Alley, R.; Brachmann, A.; Browne, M. J.; Cates, G. D.; Clendenin, J.; deLamare, J.; Frisch, J.; Galetto, T.; Hughes, E. W.; Kumar, K. S.; Mastromarino, P.; Sodja, J.; Souder, P. A.; Turner, J.; Woods, M.

    2004-04-01

    SLAC E-158 is an experiment designed to make the first measurement of parity violation in M øller scattering. E-158 will measure the right-left cross-section asymmetry, ALRM øller , in the elastic scattering of a 45-GeV polarized electron beam from unpolarized electrons in a liquid hydrogen target. E-158 plans to measure the expected Standard Model asymmetry of ˜10 -7 to an accuracy of better than 10 -8. To make this measurement, the photoemission-based polarized electron source requires an intense circularly polarized laser beam and the ability to quickly switch between right- and left-helicity polarization states with minimal right-left helicity-correlated asymmetries in the resulting beam parameters (intensity, position, angle, spot size, and energy), beamALR's. This laser beam is produced by a unique SLAC-designed flashlamp-pumped Ti:Sapphire laser and is directed through a carefully designed set of polarization optics. We analyze the transport of nearly circularly polarized light through the optical system and identify several mechanisms that generate beamALR's. We show that the dominant effects depend linearly on particular polarization phase shifts in the optical system. We present the laser system design and a discussion of the suppression and control of beamALR's. We also present results on beam performance from engineering and physics runs for E-158.

  8. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  9. Attention's Accelerator.

    PubMed

    Reinhart, Robert M G; McClenahan, Laura J; Woodman, Geoffrey F

    2016-06-01

    How do people get attention to operate at peak efficiency in high-pressure situations? We tested the hypothesis that the general mechanism that allows this is the maintenance of multiple target representations in working and long-term memory. We recorded subjects' event-related potentials (ERPs) indexing the working memory and long-term memory representations used to control attention while performing visual search. We found that subjects used both types of memories to control attention when they performed the visual search task with a large reward at stake, or when they were cued to respond as fast as possible. However, under normal circumstances, one type of target memory was sufficient for slower task performance. The use of multiple types of memory representations appears to provide converging top-down control of attention, allowing people to step on the attentional accelerator in a variety of high-pressure situations. PMID:27056975

  10. Technology of magnetically driven accelerators

    SciTech Connect

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

    1985-03-26

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

  11. Technology of magnetically driven accelerators

    SciTech Connect

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

    1985-10-01

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

  12. Pulse Power Supply for Plasma Dynamic Accelerator

    NASA Astrophysics Data System (ADS)

    Yang, Xuanzong; Liu, Jian; Feng, Chunhua; Wang, Long

    2008-06-01

    A new concept of a coaxial plasma dynamic accelerator with a self-energized magnetic compressor coil to simulate the effects of space debris impact is demonstrated. A brief description is presented about the pulse power supply system including the charging circuit, start switch and current transfer system along with some of the key techniques for this kind of accelerator. Using this accelerator configuration, ceramic beads of 100 fim in diameter were accelerated to a speed as high as 18 km/sec. The facility can be used in a laboratory setting to study impact phenomena on solar array materials, potential structural materials for use in space.

  13. STATUS OF THE DIELECTRIC WALL ACCELERATOR

    SciTech Connect

    Caporaso, G J; Chen, Y; Sampayan, S; Akana, G; Anaya, R; Blackfield, D; Carroll, J; Cook, E; Falabella, S; Guethlein, G; Harris, J; Hawkins, S; Hickman, B; Holmes, C; Horner, A; Nelson, S; Paul, A; Pearson, D; Poole, B; Richardson, R; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J; Weir, J

    2009-04-22

    The dielectric wall accelerator (DWA) system being developed at the Lawrence Livermore National Laboratory (LLNL) uses fast switched high voltage transmission lines to generate pulsed electric fields on the inside of a high gradient insulating (HGI) acceleration tube. High electric field gradients are achieved by the use of alternating insulators and conductors and short pulse times. The system is capable of accelerating any charge to mass ratio particle. Applications of high gradient proton and electron versions of this accelerator will be discussed. The status of the developmental new technologies that make the compact system possible will be reviewed. These include, high gradient vacuum insulators, solid dielectric materials, photoconductive switches and compact proton sources.

  14. Argonne plasma wake-field acceleration experiments

    SciTech Connect

    Rosenzweig, J.B.; Cole, B.; Gai, W.; Konecny, R.; Norem, J.; Schoessow, P.; Simpson, J.

    1989-03-14

    Four years after the initial proposal of the Plasma Wake-field Accelerator (PWFA), it continues to be the object of much investigation, due to the promise of the ultra-high accelerating gradients that can exist in relativistic plasma waves driven in the wake of charged particle beams. These wake-fields are of interest both in the laboratory, for acceleration and focusing of electrons and positrons in future linear colliders, and in nature as a possible cosmic ray acceleration mechanism. The purpose of the present work is to review the recent experimental advances made in PWFA research at Argonne National Laboratory. Some of the topics discussed are: the Argonne Advanced Accelerator Test Facility; linear plasma wake-field theory; measurement of linear plasma wake-fields; review of nonlinear plasma wave theory; and experimental measurement of nonlinear plasma wake-fields. 25 refs., 11 figs.

  15. Acceleration modules in linear induction accelerators

    NASA Astrophysics Data System (ADS)

    Wang, Shao-Heng; Deng, Jian-Jun

    2014-05-01

    The Linear Induction Accelerator (LIA) is a unique type of accelerator that is capable of accelerating kilo-Ampere charged particle current to tens of MeV energy. The present development of LIA in MHz bursting mode and the successful application into a synchrotron have broadened LIA's usage scope. Although the transformer model is widely used to explain the acceleration mechanism of LIAs, it is not appropriate to consider the induction electric field as the field which accelerates charged particles for many modern LIAs. We have examined the transition of the magnetic cores' functions during the LIA acceleration modules' evolution, distinguished transformer type and transmission line type LIA acceleration modules, and re-considered several related issues based on transmission line type LIA acceleration module. This clarified understanding should help in the further development and design of LIA acceleration modules.

  16. Acceleration schedules for a recirculating heavy-ion accelerator

    SciTech Connect

    Sharp, W.M.; Grote, D.P.

    2002-05-01

    Recent advances in solid-state switches have made it feasible to design programmable, high-repetition-rate pulsers for induction accelerators. These switches could lower the cost of recirculating induction accelerators, such as the ''small recirculator'' at Lawrence Livermore National Laboratory (LLNL), by substantially reducing the number of induction modules. Numerical work is reported here to determine what effects the use of fewer pulsers at higher voltage would have on the beam quality of the LLNL small recirculator. Lattices with different numbers of pulsers are examined using the fluid/envelope code CIRCE, and several schedules for acceleration and compression are compared for each configuration. For selected schedules, the phase-space dynamics is also studied using the particle-in-cell code WARP3d.

  17. High Power Klystrons: Theory and Practice at the Stanford Linear Accelerator CenterPart I

    SciTech Connect

    Caryotakis, G.

    2004-12-15

    This is Part I of a two-part report on design and manufacturing methods used at SLAC to produce accelerator klystrons. Chapter 1 begins with the history and applications for klystrons, in both of which Stanford University was extensively involved. The remaining chapters review the theory of klystron operation, derive the principal formulae used in their design, and discuss the assumptions that they involve. These formulae are subsequently used in small-signal calculations of the frequency response of a particular klystron, whose performance is also simulated by two different computer codes. The results of calculations and simulations are compared to the actual performance of the klystron.

  18. Recent performance, lifetime, and failure modes of the 5045 klystron population at SLAC

    SciTech Connect

    Koontz, R.F.; Lee, T.G.; Pearson, C.; Vlieks, A.E.

    1992-08-01

    The 65 MW S-Band klystrons (5045) used to power SLC have been in service for over seven years. Currently, 244 of these tubes are in place on the accelerator, operating full power at 120 pulses per second. Enough tubes have now reached end of life, or experienced other failures to allow a good analysis of failure modes, and to project average lifetime for this type of tube. This paper describes the various modes of failure seen in klystrons rammed from SLC service, and provides data on expected lifetime from current production based on accumulated SLC operating experience.

  19. ICFA Instrumentation Bulletin, Volume 22, Spring 2001 Issue (SLAC-J-ICFA-022)

    SciTech Connect

    Va'Vra, J.

    2003-10-21

    The publication of the ICFA Instrumentation Bulletin is an activity of the Panel on Future Innovation and Development of ICFA (International Committee for Future Accelerators). The Bulletin reports on research and progress in the field of instrumentation with emphasis on application in the field of high-energy physics. It encourages issues of generic instrumentation. This volume contains the following articles: (1) ''Gaseous Micropattern Detectors: High-Energy Physics and Beyond''; (2) ''DIRC Dreams Redux: Research Directions for the Next Generation of Internally Reflected Imaging Counters''; and (3) ''Corrosion of Glass Windows in DIRC PMTs''.

  20. Properties of Trapped Electron Bunches in a Plasma Wakefield Accelerator

    SciTech Connect

    Kirby, Neil; /SLAC

    2009-10-30

    Plasma-based accelerators use the propagation of a drive bunch through plasma to create large electric fields. Recent plasma wakefield accelerator (PWFA) experiments, carried out at the Stanford Linear Accelerator Center (SLAC), successfully doubled the energy for some of the 42 GeV drive bunch electrons in less than a meter; this feat would have required 3 km in the SLAC linac. This dissertation covers one phenomenon associated with the PWFA, electron trapping. Recently it was shown that PWFAs, operated in the nonlinear bubble regime, can trap electrons that are released by ionization inside the plasma wake and accelerate them to high energies. These trapped electrons occupy and can degrade the accelerating portion of the plasma wake, so it is important to understand their origins and how to remove them. Here, the onset of electron trapping is connected to the drive bunch properties. Additionally, the trapped electron bunches are observed with normalized transverse emittance divided by peak current, {epsilon}{sub N,x}/I{sub t}, below the level of 0.2 {micro}m/kA. A theoretical model of the trapped electron emittance, developed here, indicates that the emittance scales inversely with the square root of the plasma density in the non-linear 'bubble' regime of the PWFA. This model and simulations indicate that the observed values of {epsilon}{sub N,x}/I{sub t} result from multi-GeV trapped electron bunches with emittances of a few {micro}m and multi-kA peak currents. These properties make the trapped electrons a possible particle source for next generation light sources. This dissertation is organized as follows. The first chapter is an overview of the PWFA, which includes a review of the accelerating and focusing fields and a survey of the remaining issues for a plasma-based particle collider. Then, the second chapter examines the physics of electron trapping in the PWFA. The third chapter uses theory and simulations to analyze the properties of the trapped electron