Sample records for impact linac coherent

  1. Linac Coherent Light Source Overview

    Broader source: Energy.gov [DOE]

    Take an animated tour of the Linac Coherent Light Source (LCLS). Follow the laser pulse from the injector gun all the way through to the Far Experimental Hall.

  2. Linac Coherent Light Source Overview

    SciTech Connect (OSTI)

    None

    2010-01-01T23:59:59.000Z

    Take an animated tour of the Linac Coherent Light Source (LCLS). Follow the laser pulse from the injector gun all the way through to the Far Experimental Hall.

  3. Linac Coherent Light Source Overview

    ScienceCinema (OSTI)

    None

    2013-05-29T23:59:59.000Z

    Take an animated tour of the Linac Coherent Light Source (LCLS). Follow the laser pulse from the injector gun all the way through to the Far Experimental Hall.

  4. Enhancements to the Linac Coherent Light Source

    E-Print Network [OSTI]

    Wechsler, Risa H.

    1 Enhancements to the Linac Coherent Light Source #12;2 LCLS Strategic PlanLCLS Strategic Plan Near term - 2 years "LCLS-I" Increase user capacity flexible beam delivery through optics, linac energy and pulse length changes fixed gap afterburner at second harmonic 16 keV Intermediate term ­ 5 years "LCLS

  5. Status of the Linac Coherent Light Source

    SciTech Connect (OSTI)

    Galayda, John N.; /SLAC

    2011-11-04T23:59:59.000Z

    The Linac Coherent Light Source (LCLS) is a free electron laser facility in construction at Stanford Linear Accelerator Center. It is designed to operate in the wavelength range 0.15-1.5 nanometers. At the time of this conference, civil construction of new tunnels and buildings is complete, the necessary modifications to the SLAC linac are complete, and the undulator system and x-ray optics/diagnostics are being installed. The electron gun, 135 MeV injector linac and 250 MeV bunch compressor were commissioned in 2007. Accelerator commissioning activities are presently devoted to the achievement of performance goals for the completed 14 GeV linac.

  6. SLAC Linac Coherent Light Source User Site

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  7. Linac Coherent Light SourCe

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

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  8. Measurement and simulation of the impact of coherent synchrotron radiation on the Jefferson Laboratory energy recovery linac electron beam

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hall, C C.; Biedron, S G.; Edelen, A L.; Milton, S V.; Benson, S; Douglas, D; Li, R; Tennant, C D.; Carlsten, B E.

    2015-03-01T23:59:59.000Z

    In an experiment conducted on the Jefferson Laboratory IR free-electron laser driver, the effects of coherent synchrotron radiation (CSR) on beam quality were studied. The primary goal of this work was to explore CSR output and effect on the beam with variation of the bunch compression in the IR recirculator. Here we examine the impact of CSR on the average energy loss as a function of bunch compression as well as the impact of CSR on the energy spectrum of the bunch. Simulation of beam dynamics in the machine, including the one-dimensional CSR model, shows very good agreement with themore »measured effect of CSR on the average energy loss as a function of compression. Finally, a well-defined structure is observed in the energy spectrum with a feature in the spectrum that varies as a function of the compression. This effect is examined in simulations, as well, and a simple explanation for the variation is proposed.« less

  9. EA-1904: Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, California

    Broader source: Energy.gov [DOE]

    This EA evaluates the environmental impacts of the proposed construction of the Linac Coherent Light Source at SLAC National Accelerator Laboratory, Menlo Park, California. None available at this time. For more information, contact: Mr. Dave Osugi DOE SLAC Site Office 2575 Sand Hill Road, MS8A Menlo Park, CA 94025 E-mail: dave.osugi@sso.science.doe.gov

  10. EA-1975: LINAC Coherent Light Source-Il, SLAC National Accelerator Laboratory, Menlo Park, California

    Broader source: Energy.gov [DOE]

    DOE prepared an EA on the potential environmental impacts of a proposal to upgrade the existing LINAC Coherent Light Source (LCLS) at the SLAC National Accelerator Laboratory. The proposed LCLS-II would extend the photon energy range, increase control over photon pulses, and enable two-color pump-probe experiments. The X-ray laser beams generated by LCLS-II would enable a new class of experiments: the simultaneous investigation of a material’s electronic and structural properties.

  11. The Development of the Linac Coherent Light Source RF Gun

    E-Print Network [OSTI]

    Dowell, David H; Lewandowski, James; Limborg-Deprey, Cecile; Li, Zenghai; Schmerge, John; Vlieks, Arnold; Wang, Juwen; Xiao, Liling

    2015-01-01T23:59:59.000Z

    The Linac Coherent Light Source (LCLS) is the first x-ray laser user facility based upon a free electron laser (FEL). In addition to many other stringent requirements, the LCLS XFEL requires extraordinary beam quality to saturate at 1.5 angstroms within a 100 meter undulator.[1] This new light source is using the last kilometer of the three kilometer linac at SLAC to accelerate the beam to an energy as high as 13.6 GeV and required a new electron gun and injector to produce a very bright beam for acceleration. At the outset of the project it was recognized that existing RF guns had the potential to produce the desired beam but none had demonstrated it. This paper describes the analysis and design improvements of the BNL/SLAC/UCLA s-band gun leading to achievement of the LCLS performance goals.

  12. The linac coherent light source single particle imaging road map

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aquila, A.; Barty, A.; Bostedt, C.; Boutet, S.; Carini, G.; dePonte, D.; Drell, P.; Doniach, S.; Downing, K. H.; Earnest, T.; et al

    2015-07-01T23:59:59.000Z

    Intense femtosecond x-ray pulses from free-electron laser sources allow the imaging of individual particles in a single shot. Early experiments at the Linac Coherent Light Source (LCLS) have led to rapid progress in the field and, so far, coherent diffractive images have been recorded from biological specimens, aerosols, and quantum systems with a few-tens-of-nanometers resolution. In March 2014, LCLS held a workshop to discuss the scientific and technical challenges for reaching the ultimate goal of atomic resolution with single-shot coherent diffractive imaging. This paper summarizes the workshop findings and presents the roadmap toward reaching atomic resolution, 3D imaging at free-electronmore »laser sources.« less

  13. Optical laser systems at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Minitti, Michael P.; Robinson, Joseph S.; Coffee, Ryan N.; Edstrom, Steve; Gilevich, Sasha; Glownia, James M.; Granados, Eduardo; Hering, Philippe; Hoffmann, Matthias C.; Miahnahri, Alan; et al

    2015-05-01T23:59:59.000Z

    Ultrafast optical lasers play an essential role in exploiting the unique capabilities of recently commissioned X-ray free-electron laser facilities such as the Linac Coherent Light Source (LCLS). Pump–probe experimental techniques reveal ultrafast dynamics in atomic and molecular processes and reveal new insights in chemistry, biology, material science and high-energy-density physics. This manuscript describes the laser systems and experimental methods that enable cutting-edge optical laser/X-ray pump–probe experiments to be performed at LCLS.

  14. Beam-based Feedback for the Linac Coherent Light Source

    SciTech Connect (OSTI)

    Fairley, D.; Allison, S.; Chevtsov, S.; Chu, P.; Decker, F.J.; Emma, P.; Frisch, J.; Himel, T.; Kim, K.; Krejcik, P.; Loos, H.; Lahey, T.; Natampalli, P.; Peng, S.; Rogind, D.; Shoaee, H.; Straumann, T.; Williams, E.; White, G.; Wu, J.; Zelazney, M.; /SLAC

    2010-02-11T23:59:59.000Z

    Beam-based feedback control loops are required by the Linac Coherent Light Source (LCLS) program in order to provide fast, single-pulse stabilization of beam parameters. Eight transverse feedback loops, a 6 x 6 longitudinal feedback loop, and a loop to maintain the electron bunch charge were successfully prototyped in MATLAB for the LCLS, and have been maintaining stability of the LCLS electron beam at beam rates up to 30Hz. In the final commissioning phase of LCLS the beam will be operating at up to 120Hz. In order to run the feedback loops at beam rate, the feedback loops will be implemented in EPICS IOCs with a dedicated ethernet multi-cast network. This paper will discuss the design of the beam-based Fast Feedback System for LCLS. Topics include MATLAB feedback prototyping, algorithm for 120Hz feedback, network design for fast data transport, actuator and sensor design for single-pulse control and sensor readback, and feedback configuration and runtime control.

  15. The Coherent X-ray Imaging (CXI) Instrument at the Linac Coherent Light Source (LCLS)

    SciTech Connect (OSTI)

    Boutet, Sebastien; Williams, Garth J.; /SLAC; ,

    2011-08-16T23:59:59.000Z

    The Linac Coherent Light Source (LCLS) has become the first ever operational hard X-ray Free Electron Laser in 2009. It will operate as a user facility capable of delivering unique research opportunities in multiple fields of science. The LCLS and the LCLS Ultrafast Science Instruments (LUSI) construction projects are developing instruments designed to make full use of the capabilities afforded by the LCLS beam. One such instrument is being designed to utilize the LCLS coherent beam to image with high resolution any sub-micron object. This instrument is called the Coherent X-ray Imaging (CXI) instrument. This instrument will provide a flexible optical system capable of tailoring key beam parameters for the users. A suite of shot-to-shot diagnostics will also be provided to characterize the beam on every pulse. The provided instrumentation will include multi-purpose sample environments, sample delivery and a custom detector capable of collecting 2D data at 120 Hz. In this article, the LCLS will be briefly introduced along with the technique of Coherent X-ray Diffractive Imaging (CXDI). A few examples of scientific opportunities using the CXI instrument will be described. Finally, the conceptual layout of the instrument will be presented along with a description of the key requirements for the overall system and specific devices required.

  16. at the Stanford Linear Accelerator Center The Linac Coherent Light Source (LCLS) is transforming the face of

    E-Print Network [OSTI]

    Wechsler, Risa H.

    at the Stanford Linear Accelerator Center LCLS #12;LCLS The Linac Coherent Light Source (LCLS. A New Kind of Tool The Linac Coherent Light Source (LCLS) will produce ultra-fast pulses of X, and imaging biological materials that resist crystallization. The LCLS will create X-rays that can "see" atoms

  17. Commissioning of the Electron Line of the Linac Coherent Light Source. Dose Rate Measurements and Simulations

    SciTech Connect (OSTI)

    Santana Leitner, M; Bauer, J.M.; Fasso, A.; Liu, J.C.; Mao, X.S.; Prinz, A.; Rokni, H.; /SLAC; Sanami, T.; /SLAC /KEK, Tsukuba; Vollaire, J.; /SLAC

    2009-05-20T23:59:59.000Z

    The Linac Coherent Light Source at the SLAC National Accelerator Laboratory (operated by Stanford University for the US Department of Energy) is the world's first hard X-ray Free Electron Laser machine. It uses high energy electrons delivered by a linac to create ultrafast and brilliant X-ray pulses that can be used as a 'high-speed' camera to obtain images of atoms and molecules. LCLS is a pioneer machine and, as such, its design has encountered unprecedented challenges, the solutions to which will benefit future facilities of its kind across the globe. This article describes the radiation protection aspects of LCLS electron beamlines. Special emphasis is put on the successful commissioning of the LCLS electron line, where, for all examined loss sources, the measured prompt and residual dose rates are in agreement with or below the values predicted through detailed Monte Carlo simulations, used earlier to design the shielding.

  18. High Energy Density Science at the Linac Coherent Light Source

    SciTech Connect (OSTI)

    Lee, R W

    2007-10-19T23:59:59.000Z

    High energy density science (HEDS), as a discipline that has developed in the United States from National Nuclear Security Agency (NNSA)-sponsored laboratory research programs, is, and will remain, a major component of the NNSA science and technology strategy. Its scientific borders are not restricted to NNSA. 'Frontiers in High Energy Density Physics: The X-Games of Contemporary Science' identified numerous exciting scientific opportunities in this field, while pointing to the need for a overarching interagency plan for its evolution. Meanwhile, construction of the first x-ray free-electron laser, the Office-of-Science-funded Linear Coherent Light Source-LCLS: the world's first free electron x-ray laser, with 100-fsec time resolution, tunable x-ray energies, a high rep rate, and a 10 order-of-magnitude increase in brightness over any other x-ray source--led to the realization that the scientific needs of NNSA and the broader scientific community could be well served by an LCLS HEDS endstation employing both short-pulse and high-energy optical lasers. Development of this concept has been well received in the community. NNSA requested a workshop on the applicability of LCLS to its needs. 'High Energy Density Science at the LCLS: NNSA Defense Programs Mission Need' was held in December 2006. The workshop provided strong support for the relevance of the endstation to NNSA strategic requirements. The range of science that was addressed covered a wide swath of the vast HEDS phase space. The unique possibilities provided by the LCLS in areas of intense interest to NNSA Defense Programs were discussed. The areas of focus included warm dense matter and equations of state, hot dense matter, and behavior of high-pressure materials under conditions of high strain-rate and extreme dynamic loading. Development of new and advanced diagnostic techniques was also addressed. This report lays out the relevant science, as brief summaries (Ch. II), expanded descriptions (Ch. V), and a more detailed plans for experiments (Ch. VI), highlighting the uniqueness the HEDS endstation will play in providing mission-relevant HED data and in the development of the field. One of the more exciting aspects of NNSA-relevant experiments on LCLS is that, given the extraordinary investment and consequent advances in accurate atomic-scale simulations of matter (to a large extent via the Accelerated Scientific Computing program sponsored by NNSA), the facility will provide a platform that, for the first time, will permit experiments in the regimes of interest at the time and spatial scales of the simulations. In Chapter III, the report places the potential of LCLS with an HED science endstation in the context of science required by NNSA, as well as explicating the relationship of NNSA and HED science in general. Chapter IV discusses 4th-generation light sources, like LCLS, in the context of other laboratory technologies presently utilized by NNSA. The report concludes, noting that an HED endstation on LCLS can provide access to data in regimes that are relevant to NNSA needs but no mechanism exists for providing such data. The endstation will also serve to build a broad-based community in the 'X-Games' of physics. The science generated by the facility will be a collaboration of NNSA-based laboratory scientists and university-based researchers. The LCLS endstation fulfills the need for an intermediate-scale facility capable of delivering fundamental advances and mission-relevant research in high energy density science.

  19. Demonstration of simultaneous experiments using thin crystal multiplexing at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Feng, Y.; Alonso-Mori, R.; Barends, T. R. M.; Blank, V. D.; Botha, S.; Chollet, M.; Damiani, D. S.; Doak, R. B.; Glownia, J. M.; Koglin, J. M.; et al

    2015-05-01T23:59:59.000Z

    Multiplexing of the Linac Coherent Light Source beam was demonstrated for hard X-rays by spectral division using a near-perfect diamond thin-crystal monochromator operating in the Bragg geometry. The wavefront and coherence properties of both the reflected and transmitted beams were well preserved, thus allowing simultaneous measurements at two separate instruments. In this report, the structure determination of a prototypical protein was performed using serial femtosecond crystallography simultaneously with a femtosecond time-resolved XANES studies of photoexcited spin transition dynamics in an iron spin-crossover system. The results of both experiments using the multiplexed beams are similar to those obtained separately, using amore »dedicated beam, with no significant differences in quality.« less

  20. Electron Beam Energy Chirp Control with a Rectangular Corrugated Structure at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Zhen; Bane, Karl; Ding, Yantao; Huang, Zhirong; Iverson, Richard; Maxwell, Timothy; Stupakov, Gennady; Wang, Lanfa

    2015-01-30T23:59:59.000Z

    Electron beam energy chirp is an important parameter that affects the bandwidth and performance of a linac-based, free-electron laser. In this paper we study the wakefields generated by a beam passing between at metallic plates with small corrugations, and then apply such a device as a passive dechirper for the Linac Coherent Light Source (LCLS) energy chirp control with a multi-GeV and femtosecond electron beam. Similar devices have been tested in several places at relatively low energies (#24;100 MeV) and with relatively long bunches (> 1ps). In the parameter regime of the LCLS dechirper, with the corrugation size similar to the gap between the plates, the analytical solutions of the wakefields are no longer applicable, and we resort to a #12;field matching program to obtain the wakes. Based on the numerical calculations, we #12;fit the short-range, longitudinal wakes to simple formulas, valid over a large, useful parameter range. Finally, since the transverse wakefields - both dipole and quadrupole-are strong, we compute and include them in beam dynamics simulations to investigate the error tolerances when this device is introduced in the LCLS.

  1. Electron Beam Energy Chirp Control with a Rectangular Corrugated Structure at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Zhen; Bane, Karl; Ding, Yantao; Huang, Zhirong; Iverson, Richard; Maxwell, Timothy; Stupakov, Gennady; Wang, Lanfa

    2015-01-30T23:59:59.000Z

    Electron beam energy chirp is an important parameter that affects the bandwidth and performance of a linac-based, free-electron laser. In this paper we study the wakefields generated by a beam passing between at metallic plates with small corrugations, and then apply such a device as a passive dechirper for the Linac Coherent Light Source (LCLS) energy chirp control with a multi-GeV and femtosecond electron beam. Similar devices have been tested in several places at relatively low energies (#24;100 MeV) and with relatively long bunches (> 1ps). In the parameter regime of the LCLS dechirper, with the corrugation size similar tomore »the gap between the plates, the analytical solutions of the wakefields are no longer applicable, and we resort to a #12;field matching program to obtain the wakes. Based on the numerical calculations, we #12;fit the short-range, longitudinal wakes to simple formulas, valid over a large, useful parameter range. Finally, since the transverse wakefields - both dipole and quadrupole-are strong, we compute and include them in beam dynamics simulations to investigate the error tolerances when this device is introduced in the LCLS.« less

  2. Robust CsBr/Cu Photocathodes for the Linac Coherent Light Source

    SciTech Connect (OSTI)

    Maldonado, Juan R.; /Stanford U., Phys. Dept.; Liu, Zhi; Dowell, D.H.; Kirby, Robert E.; Sun, Yun; Pianetta, Piero; /SLAC; Pease, Fabian; /Stanford U., Phys. Dept.

    2011-06-21T23:59:59.000Z

    The linac coherent light source (LCLS), an x-ray free-electron laser project presently under construction at SLAC, uses a 2.856 GHz rf photocathode gun with a copper cathode for its electron source. While the copper cathode is performing well for the LCLS project, a cathode material with higher quantum efficiency would reduce the drive laser requirements and allow a greater range of operating conditions. Therefore a robust CsBr/Cu photocathode with greater than 50 times the quantum yield at 257 nm relative to the present LCLS copper cathode has been investigated. Preliminary experiments using a dedicated electron source development test stand at SLAC/SSRL are encouraging and are presented in this paper.

  3. Second user workshop on high-power lasers at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Heimann, Phil; Glenzer, Siegfried

    2015-05-04T23:59:59.000Z

    The second international workshop on the physics enabled by the unique combination of high-power lasers with the world-class Linac Coherent Light Source (LCLS) free-electron X-ray laser beam was held in Stanford, CA, on October 7–8, 2014. The workshop was co-organized by UC Berkeley, Lawrence Berkeley, Lawrence Livermore, and SLAC National Accelerator Laboratories. More than 120 scientists, including 40 students and postdoctoral scientists who are working in high-intensity laser-matter interactions, fusion research, and dynamic high-pressure science came together from North America, Europe, and Asia. The focus of the second workshop was on scientific highlights and the lessons learned from 16 newmore »experiments that were performed on the Matter in Extreme Conditions (MEC) instrument since the first workshop was held one year ago.« less

  4. The Coherent X-ray Imaging instrument at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Liang, Mengning; Williams, Garth J.; Messerschmidt, Marc; Seibert, M. Marvin; Montanez, Paul A.; Hayes, Matt; Milathianaki, Despina; Aquila, Andrew; Hunter, Mark S.; Koglin, Jason E.; et al

    2015-05-01T23:59:59.000Z

    The Coherent X-ray Imaging (CXI) instrument specializes in hard X-ray, in-vacuum, high power density experiments in all areas of science. Two main sample chambers, one containing a 100 nm focus and one a 1 µm focus, are available, each with multiple diagnostics, sample injection, pump–probe and detector capabilities. The flexibility of CXI has enabled it to host a diverse range of experiments, from biological to extreme matter.

  5. Single shot spatial and temporal coherence properties of the SLAC linac coherent light source in the hard x-ray regime

    SciTech Connect (OSTI)

    Gutt, C.; Wochner, P.; Fischer, B.; Conrad, H.; Castro-Colin, M.; Lee, S.; Lehmkuhler, F.; Steinke, I.; Sprung, M.; Roseker, W.; Zhu, D.; Lemke, H.; Bogle, S.; Fuoss, P. H.; Stephenson, G. B.; Cammarata, M.; Fritz, D. M.; Robert, A.; Grubel, G. (Materials Science Division); (Deutsches Elektronen-Synchrotron); (Max-Planck-Institut fur Intelligene Systeme); (LCLS, SLAC Nat. Accelerator Lab.)

    2012-01-01T23:59:59.000Z

    We measured the transverse and longitudinal coherence properties of the Linac Coherent Light Source (LCLS) at SLAC in the hard x-ray regime at 9 keV photon energy on a single shot basis. Speckle patterns recorded in the forward direction from colloidal nanoparticles yielded the transverse coherence properties of the focused LCLS beam. Speckle patterns from a gold nanopowder recorded with atomic resolution allowed us to measure the shot-to-shot variations of the spectral properties of the x-ray beam. The focused beam is in the transverse direction fully coherent with a mode number close to 1. The average number of longitudinal modes behind the Si(111) monochromator is about 14.5 and the average coherence time {tau}{sub c} = (2.0 {+-} 1.0) fs. The data suggest a mean x-ray pulse duration of (29 {+-} 14) fs behind the monochromator for (100 {+-} 14) fs long electron pulses.

  6. Absolute pulse energy measurements of soft x-rays at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tiedtke, K.; Sorokin, A. A.; Jastrow, U.; Jurani?, P.; Kreis, S.; Gerken, N.; Richter, M.; Arp, U.; Feng, Y.; Nordlund, D.; et al

    2014-01-01T23:59:59.000Z

    This paper reports novel measurements of x-ray optical radiation on an absolute scale from the intense and ultra-short radiation generated in the soft x-ray regime of a free electron laser. We give a brief description of the detection principle for radiation measurements which was specifically adapted for this photon energy range. We present data characterizing the soft x-ray instrument at the Linac Coherent Light Source (LCLS) with respect to the radiant power output and transmission by using an absolute detector temporarily placed at the downstream end of the instrument. This provides an estimation of the reflectivity of all x-ray opticalmore »elements in the beamline and provides the absolute photon number per bandwidth per pulse. This parameter is important for many experiments that need to understand the trade-offs between high energy resolution and high flux, such as experiments focused on studying materials via resonant processes. Furthermore, the results are compared with the LCLS diagnostic gas detectors to test the limits of linearity, and observations are reported on radiation contamination from spontaneous undulator radiation and higher harmonic content.« less

  7. Soft X-ray Mirrors for the Linac Coherent Light Source

    SciTech Connect (OSTI)

    Pivovaroff, M J; Bionta, R M; Mccarville, T J; Soufli, R; Stefan, P M

    2007-08-13T23:59:59.000Z

    The Linac Coherent Light Source (LCLS) is a 0.15-1.5 nm wavelength free-electron laser (FEL) being constructed at the Stanford Linear Accelerator Center (SLAC) by a multi-institution consortium, including Lawrence Livermore National Laboratory (LLNL). One of LLNL's responsibilities involves the design and construction of two grazing-incidence mirror systems whose primary intent is to reduce radiation levels in the experimental halls by separating the FEL beam from unwanted high-energy photons. This paper discusses one of these systems, the Soft X-ray Offset Mirror System (SOMS) that will operate in the wavelength range 0.62-1.5 nm (0.827-2.00 keV). The unusual properties of the FEL beam translate to stringent specifications in terms of stability, material choice and mirror properties. It also precludes using approaches previously developed for synchrotron light sources. This situation has led us to a unique mirror design, consisting of a reflective boron carbide layer deposited on a silicon substrate. In the first part of this paper, we discuss the basic system requirements for the SOMS and motivate the need for these novel reflective elements. In the second part of this paper, we discuss the development work we have performed, including simulation and experimental verification of the boron carbide coating properties, and the expected performance of the final system.

  8. The LINAC Coherent Light Source and Radiological Issues During the Commissioning

    SciTech Connect (OSTI)

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

    2010-08-26T23:59:59.000Z

    The Linac Coherent Light Source (LCLS) at SLAC National Accelerator Laboratory is the world's first X-ray free electron laser (XFEL). 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 lay-out. The general radiological issues during commissioning are presented, such as radiation dose rates and integrated doses outside the enclosure. Also, specific radiological issues related to X-ray free electron lasers are discussed. XFEL with high peak power will burn through high-Z materials. The X-ray beam needs to be blocked by stoppers when the downstream areas are occupied. LCLS stoppers feature a piece of boron carbide (B{sub 4}C), 10 mm thick. B{sub 4}C is one of the best materials since it has a low absorption coefficient for X-rays and a high melting temperature. Theoretical calculations indicate that the unfocused fluence of the LCLS XFEL beam should be about one order of magnitude below the damage threshold for bulk B{sub 4}C, for 830 eV FEL radiation. However, these calculations have not been tested experimentally and cannot be validated until LCLS begins providing 830 eV XFEL pulses. This paper describes the test plan for using the initial LCLS radiation to evaluate the survivability of B{sub 4}C and reports the preliminary results. Another major issue for LCLS is the potential radiation damage to the LCLS undulator magnets during operation. TLD dosimeters were installed along the LCLS undulators for each period of two or three weeks. This paper reports the integrated doses along the undulators with and without XFEL generation.

  9. FINDING OF NO SIGNIFICANT IMPACT FOR THE LINAC COHERENT LIGHT

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 1112011AT&T,OfficeEnd of Year 2010SaltInstrumentation andFEFACILITY1 - In the6FINDING

  10. Combining THz laser excitation with resonant soft X-ray scattering at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Turner, Joshua J.; Dakovski, Georgi L.; Hoffmann, Matthias C.; Hwang, Harold Y.; Zarem, Alex; Schlotter, William F.; Moeller, Stefan; Minitti, Michael P.; Staub, Urs; Johnson, Steven; et al

    2015-05-01T23:59:59.000Z

    This paper describes the development of new instrumentation at the Linac Coherent Light Source for conducting THz excitation experiments in an ultra high vacuum environment probed by soft X-ray diffraction. This consists of a cantilevered, fully motorized mirror system which can provide 600 kV cm?¹ electric field strengths across the sample and an X-ray detector that can span the full Ewald sphere with in-vacuum motion. The scientific applications motivated by this development, the details of the instrument, and spectra demonstrating the field strengths achieved using this newly developed system are discussed.

  11. Creating an EPICS Based Test Stand Development System for a BPM Digitizer of the Linac Coherent Light Source

    SciTech Connect (OSTI)

    Not Available

    2011-06-22T23:59:59.000Z

    The Linac Coherent Light Source (LCLS) is required to deliver a high quality electron beam for producing coherent X-rays. As a result, high resolution beam position monitoring is required. The Beam Position Monitor (BPM) digitizer acquires analog signals from the beam line and digitizes them to obtain beam position data. Although Matlab is currently being used to test the BPM digitizer?s functions and capability, the Controls Department at SLAC prefers to use Experimental Physics and Industrial Control Systems (EPICS). This paper discusses the transition of providing similar as well as enhanced functionalities, than those offered by Matlab, to test the digitizer. Altogether, the improved test stand development system can perform mathematical and statistical calculations with the waveform signals acquired from the digitizer and compute the fast Fourier transform (FFT) of the signals. Finally, logging of meaningful data into files has been added.

  12. Optical Design of a Broadband Infrared Spectrometer for Bunch Length Measurement at the Linac Coherent Light Source

    SciTech Connect (OSTI)

    Williams, Kiel; /SLAC

    2012-09-07T23:59:59.000Z

    The electron pulses generated by the Linac Coherent Light Source at the SLAC National Accelerator Laboratory occur on the order of tens of femtoseconds and cannot be directly measured by conventional means. The length of the pulses can instead be reconstructed by measuring the spectrum of optical transition radiation emitted by the electrons as they move toward a conducting foil. Because the emitted radiation occurs in the mid-infrared from 0.6 to 30 microns a novel optical layout is required. Using a helium-neon laser with wavelength 633 nm, a series of gold-coated off-axis parabolic mirrors were positioned to direct a beam through a zinc selenide prism and to a focus at a CCD camera for imaging. Constructing this layout revealed a number of novel techniques for reducing the aberrations introduced into the system by the off-axis parabolic mirrors. The beam had a recorded radius of less than a millimeter at its final focus on the CCD imager. This preliminary setup serves as a model for the spectrometer that will ultimately measure the LCLS electron pulse duration.

  13. Time-Resolved Imaging of the Microbunching Instability and Energy Spread at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ratner, D.; Behrens, C.; Deutsches Elektronen-Synchrotron DESY, Hamburg; Ding, Y.; Huang, Z.; Marinelli, A.; Maxwell, T.; Zhou, F.

    2015-03-01T23:59:59.000Z

    The microbunching instability (MBI) is a well known problem for high brightness electron beams and has been observed at accelerator facilities around the world. Free-electron lasers (FELs) are particularly susceptible to MBI, which can distort the longitudinal phase space and increase the beam’s slice energy spread (SES). Past studies of MBI at the Linac Coherent Light Source (LCLS) relied on optical transition radiation to infer the existence of microbunching. With the development of the x-band transverse deflecting cavity (XTCAV), we can for the first time directly image the longitudinal phase space at the end of the accelerator and complete amore »comprehensive study of MBI, revealing both detailed MBI behavior as well as insights into mitigation schemes. The fine time resolution of the XTCAV also provides the first LCLS measurements of the final SES, a critical parameter for many advanced FEL schemes. Detailed MBI and SES measurements can aid in understanding MBI mechanisms, benchmarking simulation codes, and designing future high- brightness accelerators.« less

  14. Time-Resolved Imaging of the Microbunching Instability and Energy Spread at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ratner, D. [SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Behrens, C. [SLAC National Accelerator Laboratory SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Ding, Y. [SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Huang, Z. [SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Marinelli, A. [SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Maxwell, T. [SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Zhou, F. [SLAC National Accelerator Laboratory, Menlo Park, CA (United States)

    2015-03-01T23:59:59.000Z

    The microbunching instability (MBI) is a well known problem for high brightness electron beams and has been observed at accelerator facilities around the world. Free-electron lasers (FELs) are particularly susceptible to MBI, which can distort the longitudinal phase space and increase the beam’s slice energy spread (SES). Past studies of MBI at the Linac Coherent Light Source (LCLS) relied on optical transition radiation to infer the existence of microbunching. With the development of the x-band transverse deflecting cavity (XTCAV), we can for the first time directly image the longitudinal phase space at the end of the accelerator and complete a comprehensive study of MBI, revealing both detailed MBI behavior as well as insights into mitigation schemes. The fine time resolution of the XTCAV also provides the first LCLS measurements of the final SES, a critical parameter for many advanced FEL schemes. Detailed MBI and SES measurements can aid in understanding MBI mechanisms, benchmarking simulation codes, and designing future high- brightness accelerators.

  15. Linac Coherent Light Source II (LCLS-II) Conceptual Design Report

    SciTech Connect (OSTI)

    Stohr, J

    2011-11-16T23:59:59.000Z

    The LCLS-II Project is designed to support the DOE Office of Science mission, as described in the 22 April 2010 Mission Need Statement. The scope of the Project was chosen to provide an increase in capabilities and capacity for the facility both at project completion in 2017 and in the subsequent decade. The Project is designed to address all points of the Mission Need Statement (MNS): (1) Expanded spectral reach; (2) Capability to provide x-ray beams with controllable polarization; (3) Capability to provide 'pump' pulses over a vastly extended range of photon energies to a sample, synchronized to LCLS-II x-ray probe pulses with controllable inter-pulse time delay; and (4) Increase of user access through parallel rather than serial x-ray beam use within the constraint of a $300M-$400M Total Project Cost (TPC) range. The LCLS-II Project will construct: (1) A hard x-ray undulator source (2-13 keV); (2) A soft x-ray undulator source (250-2,000 eV); (3) A dedicated, independent electron source for these new undulators, using sectors 10-20 of the SLAC linac; (4) Modifications to existing SLAC facilities for the injector and new shielded enclosures for the undulator sources, beam dumps and x-ray front ends; (5) A new experiment hall capable of accommodating four experiment stations; and (6) Relocation of the two soft x-ray instruments in the existing Near Experiment Hall (NEH) to the new experiment hall (Experiment Hall-II). A key objective of LCLS-II is to maintain near-term international leadership in the study of matter on the fundamental atomic length scale and the associated ultrafast time scales of atomic motion and electronic transformation. Clearly, such studies promise scientific breakthroughs in key areas of societal needs like energy, environment, health and technology, and they are uniquely enabled by forefront X-ray Free Electron Laser (X-FEL) facilities. While the implementation of LCLS-II extends to about 2017, it is important to realize that LCLS-II only constitutes a stepping stone to what we believe is needed over a longer time scale. At present, a practical time horizon for planning is about 15 years into the future, matching that of worldwide planning activities for competitive X-FEL facilities in Europe and Asia. We therefore envision LCLS-II as an important stage in development to what is required by about 2025, tentatively called LCLS-2025, for continued US leadership even as new facilities around the world are being completed. We envision LCLS primarily as a hard x-ray FEL facility with some soft x-ray capabilities. A survey of planned X-FEL facilities around the world suggests that US planning to 2025 needs to include an internationally competitive soft x-ray FEL facility which complements the LCLS plans outlined in this document.

  16. The soft x-ray instrument for materials studies at the linac coherent light source x-ray free-electron laser

    SciTech Connect (OSTI)

    Schlotter, W. F.; Turner, J. J.; Rowen, M.; Holmes, M.; Messerschmidt, M.; Moeller, S.; Krzywinski, J.; Lee, S.; Coffee, R.; Hays, G. [LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025 (United States); Heimann, P. [LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025 (United States); Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Krupin, O. [LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025 (United States); European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg (Germany); Soufli, R.; Fernandez-Perea, M.; Hau-Riege, S. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States); Kelez, N. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Beye, M.; Gerken, N.; Sorgenfrei, F.; Wurth, W. [Institute for Experimental Physics and CFEL, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); and others

    2012-04-15T23:59:59.000Z

    The soft x-ray materials science instrument is the second operational beamline at the linac coherent light source x-ray free electron laser. The instrument operates with a photon energy range of 480-2000 eV and features a grating monochromator as well as bendable refocusing mirrors. A broad range of experimental stations may be installed to study diverse scientific topics such as: ultrafast chemistry, surface science, highly correlated electron systems, matter under extreme conditions, and laboratory astrophysics. Preliminary commissioning results are presented including the first soft x-ray single-shot energy spectrum from a free electron laser.

  17. Exploring Mbar shock conditions and isochorically heated aluminum at the Matter in Extreme Conditions end station of the Linac Coherent Light Source (invited)

    SciTech Connect (OSTI)

    Fletcher, L. B. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Physics Department, University of California Berkeley, Berkeley, California 94709 (United States); Lee, H. J.; Gauthier, M.; Galtier, E.; Nagler, B.; Heimann, P.; Hastings, J. B.; Glenzer, S. H. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Barbrel, B.; Falcone, R. W. [Physics Department, University of California Berkeley, Berkeley, California 94709 (United States); Döppner, T.; LePape, S.; Ma, T.; Pak, A.; Turnbull, D. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); White, T.; Gregori, G. [Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Wei, M. [General Atomics, San Diego, California 87544 (United States); Zastrau, U. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Institute for Optics and Quantum Electronics, Friedrich-Schiller-University, 07743 Jena (Germany)

    2014-11-15T23:59:59.000Z

    Recent experiments performed at the Matter in Extreme Conditions end station of the Linac Coherent Light Source (LCLS) have demonstrated the first spectrally resolved measurements of plasmons from isochorically heated aluminum. The experiments have been performed using a seeded 8-keV x-ray laser beam as a pump and probe to both volumetrically heat and scatter x-rays from aluminum. Collective x-ray Thomson scattering spectra show a well-resolved plasmon feature that is down-shifted in energy by 19 eV. In addition, Mbar shock pressures from laser-compressed aluminum foils using velocity interferometer system for any reflector have been measured. The combination of experiments fully demonstrates the possibility to perform warm dense matter studies at the LCLS with unprecedented accuracy and precision.

  18. X-ray-optical cross-correlator for gas-phase experiments at the Linac Coherent Light Source free-electron laser

    SciTech Connect (OSTI)

    Schorb, S.; Cryan, J. P.; Glownia, J. M.; Bionta, M. R.; Coffee, R. N.; Swiggers, M.; Carron, S.; Castagna, J.-C.; Bozek, J. D.; Messerschmidt, M.; Schlotter, W. F.; Bostedt, C. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, P.O. Box 20450, Stanford, California 94309 (United States); Gorkhover, T. [Institut fuer Optik und Atomare Physik, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Erk, B.; Boll, R.; Schmidt, C.; Rudenko, A. [Max-Planck Advanced-Study-Group at CFEL, Notkestr. 85, 22607 Hamburg (Germany); Max-Planck-Institut f. Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Rolles, D. [Max-Planck Advanced-Study-Group at CFEL, Notkestr. 85, 22607 Hamburg (Germany); Max-Planck-Institut f. med. Forschung, Jahnstr. 29, 69120 Heidelberg (Germany); Rouzee, A. [Max-Born-Institut, Max-Born-Str. 2, 12489 Berlin (Germany)

    2012-03-19T23:59:59.000Z

    X-ray-optical pump-probe experiments at the Linac Coherent Light Source (LCLS) have so far been limited to a time resolution of 280 fs fwhm due to timing jitter between the accelerator-based free-electron laser (FEL) and optical lasers. We have implemented a single-shot cross-correlator for femtosecond x-ray and infrared pulses. A reference experiment relying only on the pulse arrival time information from the cross-correlator shows a time resolution better than 50 fs fwhm (22 fs rms) and also yields a direct measurement of the maximal x-ray pulse length. The improved time resolution enables ultrafast pump-probe experiments with x-ray pulses from LCLS and other FEL sources.

  19. Linac Energy Management for LCLS

    SciTech Connect (OSTI)

    Chu, Chungming; /SLAC; Iverson, Richard; /SLAC; Krejcik, Patrick; /SLAC; Rogind, Deborah; /SLAC; White, Greg; /SLAC; Woodley, Mark; /SLAC

    2012-07-05T23:59:59.000Z

    Linac Energy Management (LEM) is a control system program that scales magnet field set-point settings following a change in beam energy. LEM is necessary because changes in the number, phase, and amplitude of the active klystrons change the beam's rigidity, and therefore, to maintain constant optics, one has to change focusing gradients and bend fields accordingly. This paper describes the basic process, the control system application programs we developed for LEM, and some of the implementation lessons learned at the Linac Coherent Light Source (LCLS).

  20. Welcome to Linac Coherent Light Source | Linac Coherent Light Source

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  1. Safety | Linac Coherent Light Source

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    Safety Overview Each person who works at LCLS is required to be familiar with and identify in advance the hazards associated with hisher work, the hazards associated with work...

  2. Safety | Linac Coherent Light Source

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  3. SAC - Linac Coherent Light Source

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  4. SLAC Linac Coherent Light Source

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  5. Instability issues for the ESS linac and rings

    SciTech Connect (OSTI)

    Rees, G. H. [Rutherford Appleton Laboratory, CLRC (United Kingdom)

    1999-12-03T23:59:59.000Z

    Comments are made on beam instability issues in the ESS linac and rings. The topics of interest in the linac are halo generation in the absence and presence of machine imperfections, and also the stability of the momentum ramping of the output beam. In the case of the rings, the main concern is for fast coherent transverse instabilities due to the combined effect of coupled electron-proton oscillations and interaction with the wall impedances.

  6. CSNS LINAC DESIGN

    SciTech Connect (OSTI)

    FU, S.; FANG, S.; WEI, J.

    2006-08-21T23:59:59.000Z

    China Spallation Neutron Source has been approved in principle by the Chinese government. CSNS can provide a beam power of 100kW on the target in the first phase, and then 200kW in the second phase. The accelerator complex of CSNS consists of an H- linac of 81MeV and a rapid cycling synchrotron of 1.6GeV at 25Hz repetition rate. In the second phase, the linac energy will be upgraded to 132MeV and the average current will be doubled. The linac has been designed, and some R&D studies have started under the support from Chinese Academy of Sciences. The linac comprises a H- ion source, an RFQ and a conventional DTL with EMQs. This paper will present our major design results and some progresses in the R&D of the linac.

  7. LLRF System Upgrade for the SLAC Linac

    SciTech Connect (OSTI)

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

    2012-07-06T23:59:59.000Z

    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.

  8. High Brightness Beam Applications: Energy Recovered Linacs

    SciTech Connect (OSTI)

    Geoffrey A. Krafft

    2005-09-01T23:59:59.000Z

    In the first part of the paper some general statements are made regarding applications suitable for utilizing energy recovered linacs (ERLs) by contrasting their potential performance to that of single pass linacs and storage rings. As a result of their potential for extremely good beam quality in combination with high average beam current, ERLs have been used and considered as drivers of both free electron laser and partially coherent photon sources, from THz through X-rays; as a suitable technology for high energy electron cooling; and as a continuous or semi-continuous electron beam source for high energy colliders. At present, beam requirements tend to be highly matched to end use requirements. By reviewing some of the many examples which have either been reduced to practice, or are being explored presently, one can develop an appreciation for the wide range of parameters being considered in ERL applications.

  9. SLAC Linac Coherent Light Source User Site

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Proposal Review | PCS Proposal Review | MEC Optical-Laser-Only Proposal Review | Other LCLS Policies SUBMIT NEW PROPOSALS BY 4 pm PACIFIC on February 3, 2015. View the latest long...

  10. SLAC Linac Coherent Light Source User Site

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    User Support Contact information for LCLS scientific, operations and user support staff. User Support For information about user research administration at LCLS or SSRL. Cathy...

  11. SLAC Linac Coherent Light Source User Site

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    | Publications and Press | Proposal Preparation | Proposal Review| Beam Time Allocation LCLS Access Policy Overview LCLS aims to attract diverse users and to enable a broad set of...

  12. SLAC Linac Coherent Light Source User Site

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Publications Proposal Submission and Scheduling Step-By-Step Instructions to Working at LCLS Review LCLS Policies Review Machine FAQ & Parameters Register and Submit Proposals...

  13. Spokesperson Checklist | Linac Coherent Light Source

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  14. User Agreements | Linac Coherent Light Source

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  15. User Financial Accounts | Linac Coherent Light Source

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  16. User Shipments | Linac Coherent Light Source

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  17. LCLS Parameters Update | Linac Coherent Light Source

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  18. LCLS Policies | Linac Coherent Light Source

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  19. Collaborator Checklist | Linac Coherent Light Source

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  20. Committees & Contacts | Linac Coherent Light Source

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  1. Contact Us | Linac Coherent Light Source

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  2. SLAC Linac Coherent Light Source User Site

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  3. SLAC Linac Coherent Light Source User Site

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  4. SLAC Linac Coherent Light Source User Site

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  5. Becoming a User | Linac Coherent Light Source

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  6. Bioimaging Workshop - Linac Coherent Light Source

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  7. Working at SLAC | Linac Coherent Light Source

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  8. The Linac Coherent Light Source is

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  9. After Beamtime | Linac Coherent Light Source

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  10. Food Options | Linac Coherent Light Source

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  11. Proposal Submission | Linac Coherent Light Source

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  12. Progress in Induction Linacs

    SciTech Connect (OSTI)

    Caporaso, G J

    2000-09-27T23:59:59.000Z

    This presentation will be a broad survey of progress in induction technology over the past four years. Much work has been done on accelerators for hydrodynamic test radiography and other applications. Solid-state pulsers have been developed which can provide unprecedented flexibility and precision in pulse format and accelerating voltage for both ion and electron induction machines. Induction linacs can now be built which can operate with MHz repetition rates. Solid-state technology has also made possible the development of fast kickers for precision control of high current beams. New insulator technology has been developed which will improve conventional induction linacs in addition to enabling a new class of high gradient induction linacs.

  13. The Fermilab Linac Upgrade

    SciTech Connect (OSTI)

    Noble, R.J.

    1991-02-01T23:59:59.000Z

    The Fermilab Linac Upgrade is planned to increase the energy of the H- linac from 200 to 400 MeV. This is intended to reduce the incoherent space-charge tuneshift at injection into the 8 GeV Booster which can limit either the brightness or the total intensity of the beam. The Linac Upgrade will be achieved by replacing the last four 201.25 MHz drift-tube tanks which accelerate the beam from 116 to 200 MeV, with seven 805 MHz side-coupled cavity modules operating at an average axial field of abut 7.5 MV/m. This will allow acceleration to 400 MeV in the existing Linac enclosure. Each accelerator module will be driven with a klystron-based rf power supply. A prototype rf modulator has been built and tested at Fermilab, and a prototype 12 MW klystron is being fabricated by Litton Electron Devices. Fabrication of production accelerator modules is in progress. 8 figs., 4 tabs.

  14. Identifying Longitudinal Jitter Sources in the LCLS Linac

    SciTech Connect (OSTI)

    Decker, Franz-Josef; /SLAC; Akre, Ron; /SLAC; Brachmann, Axel; /SLAC; Craft, Jim; /SLAC; Ding, Yuantao; /SLAC; Dowell, David; /SLAC; Emma, Paul; /SLAC; Frisch, Josef; /SLAC; Huang, Zhirong; /SLAC; Iverson, Richard; /SLAC; Krasnykh, Anatoly; /SLAC; Loos, Henrik; /SLAC; Nuhn, Heinz-Dieter; /SLAC; Ratner, Daniel; /SLAC; Smith, Tonee; /SLAC; Turner, James; /SLAC; Welch, James; /SLAC; White, William; /SLAC; Wu, Juhao; /SLAC

    2012-07-06T23:59:59.000Z

    The Linac Coherent Light Source (LCLS) at SLAC is an x-ray Free Electron Laser (FEL) with wavelengths of 0.15 nm to 1.5 nm. The electron beam stability is important for good lasing. While the transverse jitter of the beam is about 10-20% of the rms beam sizes, the jitter in the longitudinal phase space is a multiple of the energy spread and bunch length. At the lower energy of 4.3 GeV (corresponding to the longest wavelength of 1.5 nm) the relative energy jitter can be 0.125%, while the rms energy spread is with 0.025% five times smaller. An even bigger ratio exists for the arrival time jitter of 50 fs and the bunch duration of about 5 fs (rms) in the low charge (20 pC) operating mode. Although the impact to the experiments is reduced by providing pulse-by-pulse data of the measured energy and arrival time, it would be nice to understand and mitigate the root causes of this jitter. The thyratron of the high power supply of the RF klystrons is one of the main contributors. Another suspect is the multi-pacting in the RF loads. Phase measurements down to 0.01 degree (equals 10 fs) along the RF pulse were achieved, giving hints to the impact of the different sources.

  15. LINAC COHERENT LIGHT SOURCE The Linac Coherent Light Source at SLAC National Accelerator Laboratory is

    E-Print Network [OSTI]

    Wechsler, Risa H.

    is the world's most powerful X-ray laser. The LCLS's highly focused beam, which arrives in staccato bursts one-rays are scientists' best tool for probing matter on the atomic scale, and the LCLS is an x-ray source unlike any before. Shining a billion times brighter than previous X-ray sources, the LCLS probes matter in new ways

  16. Construction Status of Linac4

    E-Print Network [OSTI]

    Gerigk, F; Garoby, R; Hanke, K; Lombardi, A M; MacCaferri, R; Maury, S; Rossi, C; Vretenar, M

    2010-01-01T23:59:59.000Z

    The civil engineering works of the Linac4 linear accelerator at CERN started in October 2008 and regular machine operation is foreseen for 2013. Linac4 will accelerate H?ions to an energy of 160 MeV for injection into the PS Booster (PSB). It will thus replace the ageing Linac2, which presently injects at 50 MeV into the PSB, and it will also represents the first step in the injector upgrade for the LHC aiming at increasing its luminosity. This paper reports on the status of the design and construction of the main machine elements, which will be installed in the linac tunnel from the beginning of 2012 onwards, on the progress of the civil engineering and on the ongoing activities at the Linac4 test stand.

  17. Linac4 Technical Design Report

    E-Print Network [OSTI]

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

    2006-01-01T23:59:59.000Z

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

  18. Optimization of SRF Linacs

    SciTech Connect (OSTI)

    Powers, Tom [JLAB

    2013-09-01T23:59:59.000Z

    This work describes preliminary results of a new software tool that allows one to vary parameters and understand the effects on the optimized costs of construction plus 10 year operations of an SRF linac, the associated cryogenic facility, and controls, where operations includes the cost of the electrical utilities but not the labor or other costs. It derives from collaborative work done with staff from Accelerator Science and Technology Centre, Daresbury, UK several years ago while they were in the process of developing a conceptual design for the New Light Source project.[1] The initial goal was to convert a spread sheet format to a graphical interface to allow the ability to sweep different parameter sets. The tools also allow one to compare the cost of the different facets of the machine design and operations so as to better understand the tradeoffs. The work was first published in an ICFA Beam Dynamics News Letter.[2] More recent additions to the software include the ability to save and restore input parameters as well as to adjust the Qo versus E parameters in order to explore the potential costs savings associated with doing so. Additionally, program changes now allow one to model the costs associated with a linac that makes use of energy recovery mode of operation.

  19. Induction Linac Pulsers

    SciTech Connect (OSTI)

    Faltens, Andris

    2011-01-07T23:59:59.000Z

    The pulsers used in most of the induction linacs evolved from the very large body of work that was done in the U.S. and Great Britain during the development of the pulsed magnetron for radar. The radar modulators started at {approx}100 kW and reached >10 MW by 1945. A typical pulse length was 1 {mu}s at a repetition rate of 1,000 pps. A very comprehensive account of the modulator development is Pulse Generators by Lebacqz and Glasoe, one of the Radiation Laboratory Series. There are many permutations of possible modulators, two of the choices being tube type and line type. In earlier notes I wrote that technically the vacuum tube pulser met all of our induction linac needs, in the sense that a number of tubes, in series and parallel if required, could produce our pulses, regulate their voltage, be useable in feed-forward correctors, and provide a low source impedance. At a lower speed, an FET array is similar, and we have obtained and tested a large array capable of >10 MW switching. A modulator with an electronically controlled output only needs a capacitor for energy storage and in a switched mode can transfer the energy from the capacitor to the load at high efficiency. Driving a full size Astron induction core and a simulated resistive 'beam load' we achieved >50% efficiency. These electronically controlled output pulses can produce the pulses we desire but are not used because of their high cost. The second choice, the line type pulser, visually comprises a closing switch and a distributed or a lumped element transmission line. The typical switch cannot open or stop conducting after the desired pulse has been produced, and consequently all of the initially stored energy is dissipated. This approximately halves the efficiency, and the original cost estimating program LIACEP used this factor of two, even though our circuits are usually worse, and even though our inveterate optimists often omit it. The 'missing' energy is that which is reflected back into the line from mismatches, the energy left in the accelerator module's capacitance, the energy lost in the switch during switching and during the pulse, and the energy lost in the pulse line charging circuit. For example, a simple resistor-limited power supply dissipates as much energy as it delivers to the pulse forming line, giving a factor if two by itself, therefore efficiency requires a more complicated charging system.

  20. Source of coherent short wavelength radiation

    DOE Patents [OSTI]

    Villa, Francesco (Alameda, CA)

    1990-01-01T23:59:59.000Z

    An apparatus for producing coherent radiation ranging from X-rays to the far ultraviolet (i.e., 1 Kev to 10 eV) utilizing the Compton scattering effect. A photon beam from a laser is scattered on a high energy electron bunch from a pulse power linac. The short wavelength radiation produced by such scattering has sufficient intensity and spatial coherence for use in high resolution applications such as microscopy.

  1. PROGRESS IN DESIGN OF THE SNS LINAC

    SciTech Connect (OSTI)

    R. HARDEKOPF

    2000-11-01T23:59:59.000Z

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

  2. Photons with a Twist: Coherent Optical Vortices From Relativistic Electron Beams

    E-Print Network [OSTI]

    Knyazik, Andrey

    2013-01-01T23:59:59.000Z

    Linac Coherent Light Source (LCLS) FEL at SLAC operating atBW [5] with plans of upgrading LCLS, and mak- ing x-ray FELsingle pass sources like LCLS is that techniques described

  3. LFSC - Linac Feedback Simulation Code

    SciTech Connect (OSTI)

    Ivanov, Valentin; /Fermilab

    2008-05-01T23:59:59.000Z

    The computer program LFSC (<Linac Feedback Simulation Code>) is a numerical tool for simulation beam based feedback in high performance linacs. The code LFSC is based on the earlier version developed by a collective of authors at SLAC (L.Hendrickson, R. McEwen, T. Himel, H. Shoaee, S. Shah, P. Emma, P. Schultz) during 1990-2005. That code was successively used in simulation of SLC, TESLA, CLIC and NLC projects. It can simulate as pulse-to-pulse feedback on timescale corresponding to 5-100 Hz, as slower feedbacks, operating in the 0.1-1 Hz range in the Main Linac and Beam Delivery System. The code LFSC is running under Matlab for MS Windows operating system. It contains about 30,000 lines of source code in more than 260 subroutines. The code uses the LIAR ('Linear Accelerator Research code') for particle tracking under ground motion and technical noise perturbations. It uses the Guinea Pig code to simulate the luminosity performance. A set of input files includes the lattice description (XSIF format), and plane text files with numerical parameters, wake fields, ground motion data etc. The Matlab environment provides a flexible system for graphical output.

  4. Heavy ion, recirculating linac, design optimization

    SciTech Connect (OSTI)

    Hewett, D.W. (Lawrence Livermore National Lab., CA (United States)); Godlove, T.F. (FM Technologies, Inc., Fairfax Station, VA (United States))

    1991-06-04T23:59:59.000Z

    Cost optimization is important to the development of high-current, heavy-ion accelerators for power production based on inertial confinement fusion. Two heavy-ion, recirculating linac configurations are examined that eliminate the necessity to provide reset pulses for the cores used in the linac induction accelerating modules. 3 refs., 2 figs.

  5. STANFORD SYNCHROTRON RADIATION LIGHTSOURCE LINAC COHERENT LIGHT SOURCE

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  6. LCLS Experimental Run Schedules | Linac Coherent Light Source

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  7. User Research Administration & Support | Linac Coherent Light Source

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  8. LCLS User Check-In Procedures | Linac Coherent Light Source

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  9. LCLS Users' Organization Executive Committee | Linac Coherent Light Source

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  10. Before Arriving at SLAC | Linac Coherent Light Source

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  11. Science and Instrumentation for the Linac Coherent Light Source Workshop

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  12. Beam Dynamics Study of X-Band Linac Driven X-Ray FELS

    SciTech Connect (OSTI)

    Adolphsen, C.; Limborg-Deprey, C.; Raubenheimer, T.O.; Wu, J.; /SLAC; Sun, Y.; /SLAC

    2011-12-13T23:59:59.000Z

    Several linac driven X-ray Free Electron Lasers (XFELs) are being developed to provide high brightness photon beams with very short, tunable wavelengths. In this paper, three XFEL configurations are proposed that achieve LCLS-like performance using X-band linac drivers. These linacs are more versatile, efficient and compact than ones using S-band or C-band rf technology. For each of the designs, the overall accelerator layout and the shaping of the bunch longitudinal phase space are described briefly. During the last 40 years, the photon wavelengths from linac driven FELs have been pushed shorter by increasing the electron beam energy and adopting shorter period undulators. Recently, the wavelengths have reached the X-ray range, with FLASH (Free-Electron Laser in Hamburg) and LCLS (Linac Coherent Light Source) successfully providing users with soft and hard X-rays, respectively. FLASH uses a 1.2 GeV L-band (1.3 GHz) superconducting linac driver and can deliver 10-70 fs FWHM long photon pulses in a wavelength range of 44 nm to 4.1 nm. LCLS uses the last third of the SLAC 3 km S-band (2.856 GHz) normal-conducting linac to produce 3.5 GeV to 15 GeV bunches to generate soft and hard X-rays with good spatial coherence at wavelengths from 2.2 nm to 0.12 nm. Newer XFELs (at Spring8 and PSI) use C-band (5.7 GHz) normal-conducting linac drivers, which can sustain higher acceleration gradients, and hence shorten the linac length, and are more efficient at converting rf energy to bunch energy. The X-band (11.4 GHz) rf technology developed for NLC/GLC offers even higher gradients and efficiencies, and the shorter rf wavelength allows more versatility in longitudinal bunch phase space compression and manipulation. In the following sections, three different configurations of X-band linac driven XFELs are described that operate from 6 to 14 GeV. The first (LOW CHARGE DESIGN) has an electron bunch charge of only 10 pC; the second (OPTICS LINEARIZATION DESIGN) is based on optics linearization of the longitudinal phase space in the first stage bunch compressor and can operate with either a high (250 pC) or low (20 pC) bunch charge; and the third (LCLS INJECTOR DESIGN) is similar to LCLS but uses an X-band linac after the first stage bunch compressor at 250 MeV to achieve a final beam energy up to 14 GeV. Compared with LCLS, these X-band linacs are at least a factor of three shorter.

  13. REVIEW OF SCIENTIFIC INSTRUMENTS 84, 022701 (2013) Intense terahertz pulses from SLAC electron beams using coherent

    E-Print Network [OSTI]

    2013-01-01T23:59:59.000Z

    February 2013) SLAC has two electron accelerators, the Linac Coherent Light Source (LCLS) and the Facility via coherent transition radiation. For LCLS and FACET respectively, the THz pulse duration field at a THz focus has reached 4.4 GV/m (0.44 V/Å) at LCLS. This paper presents measurements

  14. Benchmark of the IMPACT Code for High Intensity Beam DynamicsSimulation

    SciTech Connect (OSTI)

    Qiang, J.; Ryne, R.D.

    2006-11-16T23:59:59.000Z

    The IMPACT (Integrated Map and Particle Accelerator Tracking) code was first developed under Computational Grand Challenge project in the mid 1990s [1]. It started as a three-dimensional (3D) data parallel particle-in-cell (PIC) code written in High Performance Fortran. The code used a split-operator based method to solve the Hamiltonian equations of motion. It contained linear transfer maps for drifts, quadrupole magnets and rf cavities. The space-charge forces were calculated using an FFT-based method with 3D open boundary conditions and longitudinal periodic boundary conditions. This code was completely rewritten in the late 1990s based on a message passing parallel programming paradigm using Fortran 90 and MPI following an object-oriented software design. This improved the code's scalability on large parallel computer systems and also gave the code better software maintainability and extensibility [2]. In the following years, under the SciDAC-1 accelerator project, the code was extended to include more accelerating and focusing elements such as DTL, CCL, superconducting linac, solenoid, dipole, multipoles, and others. Besides the original split-operator based integrator, a direct integration of Lorentz equations of motion using a leap-frog algorithm was also added to the IMPACT code to handle arbitrary external nonlinear fields. This integrator can read in 3D electromagnetic fields in a Cartesian grid or in a cylindrical coordinate system. Using the Lorentz integrator, we also extended the original code to handle multiple charge-state beams. The space-charge solvers were also extended to include conducting wall effects for round and rectangular pipes with longitudinal open and periodic boundary conditions. Recently, it has also been extended to handle short-range wake fields (longitudinal monopole and transverse dipole) and longitudinal coherent synchrotron radiation wake fields. Besides the parallel macroparticle tracking code, an rf linac lattice design code, an envelope matching and analysis code, and a number of pre- and post-processing codes were also developed to form the IMPACT code suite. The IMPACT code suite has been used to study beam dynamics in the SNS linac, the J-PARC linac commissioning, the CERN superconducting linac design, the Los Alamos Low Energy Demonstration Accelerator (LEDA) halo experiment, the Rare Isotope Accelerator (RIA) driver linac design, and the FERMI{at}Elettra FEL linac design [3-8]. It has also been used to study space-charge resonance in anisotropic beams [9-11].

  15. The LINAC4 Project at CERN

    E-Print Network [OSTI]

    Arnaudon, L; Bertone, C; Body, Y; Broere, J; Brunner, O; Buzio, M; Carli, C; Caspers, F; Corso, JP; Coupard, J; Dallocchio, A; Dos Santos, N; Garoby, R; Gerigk, F; Hammouti, L; Hanke, K; Jones, M; Kozsar, I; Lettry, J; Lallement, JB; Lombardi, A; Lopez-Hernandez, LA; Maglioni, C; Mathot, S; Maury, S; Mikulec, B; Nisbet, D; Noels, C; Paoluzzi, M; Puccio, B; Raich, U; Ramberger, S; Rossi, C; Schwerg, N; Scrivens, R; Vandoni, G; Weisz, S; Vollaire, J; Vretenar, M; Zickler, T

    2011-01-01T23:59:59.000Z

    As the first step of a long-term programme aiming at an increase in the LHC luminosity, CERN is building a new 160 MeV H¯ linear accelerator, Linac4, to replace the ageing 50 MeV Linac2 as injector to the PS Booster (PSB). Linac4 is an 86-m long normal-conducting linac made of an H¯ source, a Radio Frequency Quadrupole (RFQ), a chopping line and a sequence of three accelerating structures: a Drift-Tube Linac (DTL), a Cell-Coupled DTL (CCDTL) and a Pi-Mode Structure (PIMS). The civil engineering has been recently completed, and construction of the main accelerator components has started with the support of a network of international collaborations. The low-energy section up to 3 MeV including a 3-m long 352 MHz RFQ entirely built at CERN is in the final construction phase and is being installed on a dedicated test stand. The present schedule foresees beam commissioning of the accelerator in the new tunnel in 2013/14; the moment of connection of the new linac to the CERN accelerator chain will depend on the L...

  16. Status of the LINAC4 Project at CERN

    E-Print Network [OSTI]

    Hanke, K; Garoby, R; Gerigk, F; Lombardi, A; Maury, S; Rossi, C; Vretenar, M

    2010-01-01T23:59:59.000Z

    The construction of Linac4, a 160 MeV H- Linac, is the first step in upgrading the LHC injector chain. Unlike CERN’s present injector linac, Linac4 will inject into the subsequent synchrotron via charge exchange injection. In a first stage, it will inject into the existing CERN PS Booster. At a later stage, Linac4 has the option to be extended by a superconducting linac (SPL) which could then inject into a new synchrotron (PS2). Construction of Linac4 has started in 2008, and beam operation is presently planned for 2015. An overview of the Linac4 main parameters and design choices is given, and the status of the construction reported.

  17. The calculation of differential cross sections, polarization factions, electron-impact coherence parameters and fine-structure-effect spin-polarization functions for the electron-impact excitation of neon

    SciTech Connect (OSTI)

    Cartwright, D.C.; Csanak, G.; Machado, L.E.; Meneses, G.D. [Los Alamos National Laboratory, NM (United States)

    1993-05-01T23:59:59.000Z

    First-order many-body theory (FOMBT) has been used for the calculation of cross sections (DCSs), polarization fractions, a complete set of electron-impact coherence parameters, and fine-structure-effect spin-polarizations for the 1S{sub 0}-3P{sub 0,1,2} excitation of Ne. Results will be reported for E = 20, 25, 30, 50, 80, 100 and 120 eV incident electron energies and will be compared with available experimental data.

  18. ILC Linac R&D at SLAC

    SciTech Connect (OSTI)

    Adolphsen, C.; /SLAC

    2006-08-09T23:59:59.000Z

    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.

  19. Progress of APT superconducting linac engineering development

    SciTech Connect (OSTI)

    Chan, K.C.D.; Campbell, B.M.; Gentzlinger, R.C.; Balleyguier, P.; Waynert, J.A.; Haynes, W.B.; Kelley, J.P.; Rusnak, B.; Safa, H.

    1998-12-31T23:59:59.000Z

    The authors initiated a program to develop superconducting (SC) RF for high-power proton linacs. These linacs are useful in accelerator-driven transmutation technologies and the Accelerator Production of Tritium (APT) Project. They are developing multicell niobium cavities with elliptical-cell shapes at 700 MHz. These cavities, unlike most elliptical cavities for electron accelerators, are designed to accelerate protons at {beta}<1. Coaxial power couplers are being developed to transmit high (250 kW) CW RF power to the cavities. The couplers will be tested both at ambient temperature and at cryogenic temperature (2K). Their power handling and thermal properties will be measured. The cavities and power couplers will be integrated into a prototype cryomodule. The cryomodule will be tested and characterized with RF under cryogenic conditions required for a high-power proton linac. This paper describes the status of this program.

  20. Coupled-cavity drift-tube linac

    DOE Patents [OSTI]

    Billen, J.H.

    1996-11-26T23:59:59.000Z

    A coupled-cavity drift-tube linac (CCDTL) combines features of the Alvarez drift-tube linac (DTL) and the {pi}-mode coupled-cavity linac (CCL). In one embodiment, each accelerating cavity is a two-cell, 0-mode DTL. The center-to-center distance between accelerating gaps is {beta}{lambda}, where {lambda} is the free-space wavelength of the resonant mode. Adjacent accelerating cavities have oppositely directed electric fields, alternating in phase by 180 degrees. The chain of cavities operates in a {pi}/2 structure mode so the coupling cavities are nominally unexcited. The CCDTL configuration provides an rf structure with high shunt impedance for intermediate velocity charged particles, i.e., particles with energies in the 20-200 MeV range. 5 figs.

  1. LT-C-ESH-LCASE-001, Ver. 3 Linac Commissioning

    E-Print Network [OSTI]

    Ohta, Shigemi

    the commissioning with electron beam of the National Synchrotron Light Source II (NSLS-II) Linac system, which in the NSLS-II Linac Commissioning Safety Assessment Document (LCSAD). NSLS-II considers failure to meetLT-C-ESH-LCASE-001, Ver. 3 Linac Commissioning Accelerator Safety Envelope For the National

  2. Superconducting spoke LINAC design as an alternative option for the CERN LINAC4 high energy part

    E-Print Network [OSTI]

    Sargsyan, E; CERN. Geneva. AB Department

    2006-01-01T23:59:59.000Z

    A standard normal-conducting Side Coupled Linac (SCL) has been chosen as a mainline solution for the CERN LINAC4/SPL to accelerate the beam from 90-160/180 MeV. This type of structure is well known and operates at twice the basic frequency (704.4 MHz). Two alternative superconducting solutions with elliptical and triple-spoke cavities have been studied for this energy range. The present note summarizes the beam dynamics calculations in the superconducting triple-spoke linac section analyzing advantages/disadvantages.

  3. Coherent diffraction of a single virus particle: The impact of a water layer on the available orientational information

    SciTech Connect (OSTI)

    Wang, F.; Weckert, E.; Ziaja, B.; Larsson, D. S. D.; Spoel, D. van der [HASYLAB, Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22607 Hamburg (Germany); Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22607 Hamburg (Germany); Department of Cell and Molecular Biology, Uppsala University, Box 596, S-75124 Uppsala (Sweden)

    2011-03-15T23:59:59.000Z

    Coherent diffractive imaging using x-ray free-electron lasers (XFELs) may provide a unique opportunity for high-resolution structural analysis of single particles sprayed from an aqueous solution into the laser beam. As a result, diffraction images are measured from randomly oriented objects covered by a water layer. We analyze theoretically how the thickness of the covering water layer influences the structural and orientational information contained in the recorded diffraction images. This study has implications for planned experiments on single-particle imaging with XFELs.

  4. A Stability of LCLS Linac Modulators

    SciTech Connect (OSTI)

    Decker, F.-J.; Krasnykh, A.; Morris, B.; Nguyen, M.; /SLAC

    2012-06-13T23:59:59.000Z

    Information concerning to a stability of LCLS RF linac modulators is allocated in this paper. In general a 'pulse-to-pulse' modulator stability (and RF phase as well) is acceptable for the LCLS commission and FEL programs. Further modulator stability improvements are possible and approaches are discussed based on our experimental results.

  5. Finding of No Significant Impact for the Construction and Operation of the Linac Coherent Light Source (LCLS) at the Stanford Linear Accelerator Center (SLAC), California (DOE/EA-1426) (2/28/03)

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directed offOCHCO2: FinalOffers New Training on Energy6 FederalofE:FinancingFinding a Career in Energy OF

  6. Transverse-coherence properties of the FEL at the LCLS

    SciTech Connect (OSTI)

    Ding, Yuantao

    2010-09-02T23:59:59.000Z

    The recently commissioned Linac Coherent Light Source is an x-ray free-electron laser at the SLAC National Accelerator Laboratory, which is now operating at x-ray wavelengths of 20-1.2 Angstrom with peak brightness nearly ten orders of magnitude beyond conventional synchrotron sources. Understanding of coherence properties of the radiation from SASE FELs at LCLS is of great practical importance for some user experiments. We present the numerical analysis of the coherence properties at different wavelengths based on a fast algorithmusing ideal and start-end simulated FEL fields. The sucessful commissioning and operation of the linac coherent light source (LCLS) [1] has demonstrated that the x-ray free-electron laser (FEL) has come of age; these types of x-ray sources are poised to revolutionize the ultra-fast x-ray sciences. The LCLS and other hard x-ray FELs under construction are based on the principle of self-amplified spontaneous emission (SASE) [2, 3], where the amplification process starts from the shot noise in the electron beam. A large number of transverse radiation modes are also excited when the electron beam enters the undulator. The FEL collective instability in the electron beam causes the modulation of the electron density to increase exponentially, and after sufficient undulator distances, a single transverse mode starts to dominate. As a result, SASE FEL is almost fully coherent in the transverse dimension. Understanding of transverse coherence properties of the radiation from SASE FELs is of great practical importance. The longitudinal coherence properties of SASE FELs have been studied before [4]. Some studies on the transverse coherence can be found in previous papers, for example, in ref. [5, 6, 7, 8, 9]. In this paper, we first discuss a new numerical algorithm based on Markov chain Monte Carlo techniques to calculate the FEL transverse coherence. Then we focus on the numerical analysis of the LCLS FEL transverse coherence.

  7. Induction linacs for heavy ion fusion research

    SciTech Connect (OSTI)

    Fessenden, T.J.

    1984-05-01T23:59:59.000Z

    The new features of employing an induction linac as a driver for inertial fusion involve (1) transport of high-current low-emittance heavy ion beams, (2) multiple independently-focussed beams threading the same accelerator structure, and (3) synthesis of voltage waveforms to accomplish beam current amplification. A research program is underway at LBL to develop accelerators that test all these features with the final goal of producing an ion beam capable of heating matter to approx. 70 eV. This paper presents a discussion of some properties of induction linacs and how they may be used for HIF research. Physics designs of the High Temperature Experiment (HTE) and the Multiple Beam Experiment (MBE) accelerators are presented along with initial concepts of the MBE induction units.

  8. Catalytic Coherence

    E-Print Network [OSTI]

    Johan Aberg

    2014-10-20T23:59:59.000Z

    Due to conservation of energy we cannot directly turn a quantum system with a definite energy into a superposition of different energies. However, if we have access to an additional resource in terms of a system with a high degree of coherence, as for standard models of laser light, we can overcome this limitation. The question is to what extent coherence gets degraded when utilized. Here it is shown that coherence can be turned into a catalyst, meaning that we can use it repeatedly without ever diminishing its power to enable coherent operations. This finding stands in contrast to the degradation of other quantum resources, and has direct consequences for quantum thermodynamics, as it shows that latent energy that may be locked into superpositions of energy eigenstates can be released catalytically.

  9. LINAC-based transuranic waste characterization system

    SciTech Connect (OSTI)

    Schultz, F.J.; Womble, P.C. [Oak Ridge National Lab., TN (United States); Vourvopoulos, G. [Western Kentucky Univ., Bowling Green, KY (United States); Roberts, M.L. [Lawrence Livermore National Lab., CA (United States)

    1994-12-31T23:59:59.000Z

    Remote-handled transuranic nuclear waste poses a particular challenge for assaying due to the high neutron and gamma ray background that emanates from the non-fissile, but highly radioactive material, contained with the waste. The utilization of a RFQ linac with a neutron flux has shown that, in principle, the differential die-away technique can reliably assay this special class of nuclear waste.

  10. Retroactive Coherence

    E-Print Network [OSTI]

    J. B. Peterson

    2002-03-15T23:59:59.000Z

    In gravitational microlensing, interference visibility is established when the spectral resolution of the observation is less than the reciprocal of the time delay difference. Using high resolutionspectroscopy fringes will be visible at large path differences, even when the source emission is incoherent. This is possible because coherence can be established after interference has already occurred. Results of a laboratory test are presented which demonstrate this retroactive establishment of coherence.

  11. Advanced RF power sources for linacs

    SciTech Connect (OSTI)

    Wilson, P.B.

    1996-10-01T23:59:59.000Z

    In order to maintain a reasonable over-all length at high center-of-mass energy, the main linac of an electron-positron linear collider must operate at a high accelerating gradient. For copper (non-superconducting) accelerator structures, this implies a high peak power per unit length and a high peak power per RF source, assuming a limited number of discrete sources are used. To provide this power, a number of devices are currently under active development or conceptual consideration: conventional klystrons with multi-cavity output structures, gyroklystrons, magnicons, sheet-beam klystrons, multiple-beam klystrons and amplifiers based on the FEL principle. To enhance the peak power produced by an rf source, the SLED rf pulse compression scheme is currently in use on existing linacs, and new compression methods that produce a flatter output pulse are being considered for future linear colliders. This paper covers the present status and future outlook for the more important rf power sources and pulse compression systems. It should be noted that high gradient electron linacs have applications in addition to high-energy linear colliders; they can, for example, serve as compact injectors for FEL`s and storage rings.

  12. Evaluation of photoneutron production at high energy LINACS

    SciTech Connect (OSTI)

    Bell, Z.W.

    1995-04-24T23:59:59.000Z

    This report describes an estimate of neutron production at a 9 MeV LINAC, and the potential for photoactivation of materials present at the LINAC facility. It was found that only isotopes of U, W, Ta, and Pb had daughters whose activities might be measurable. The LINAC was found to be capable of producing in the neighborhood of 10{sup 10} neutrons/second from these heavy metals, and that subsequent neutron activation might be more of a concern. Monte Carlo simulation of neutron transport and capture in the concrete and steel found in the LINAC vault indicates that {sup 55}Fe may be produced in measurable quantities.

  13. Suppression of microbunching instability using bending magnets in FEL linacs

    E-Print Network [OSTI]

    Qiang, Ji

    2014-01-01T23:59:59.000Z

    using bending magnets in FEL linacs Ji Qiang, Chad E.for free electron laser (FEL) radiation. In this letter, weaccelerators for next generation FEL light sources. Instead

  14. SIMULATIONS OF A MUON LINAC FOR A NEUTRINO FACTORY

    SciTech Connect (OSTI)

    Kevin Beard, Alex Bogacz ,Slawomir Bogacz, Vasiliy Morozov, Yves Roblin

    2011-04-01T23:59:59.000Z

    The Neutrino Factory baseline design involves a complex chain of accelerators including a single-pass linac, two recirculating linacs and an FFAG. The first linac follows the capture and bunching section and accelerates the muons from about 244 to 900 MeV. It must accept a high emittance beam about 30 cm wide with a 10% energy spread. This linac uses counterwound, shielded superconducting solenoids and 201 MHz superconducting cavities. Simulations have been carried out using several codes including Zgoubi, OptiM, GPT, Elegant and G4beamline, both to determine the optics and to estimate the radiation loads on the elements due to beam loss and muon decay.

  15. Optical emission spectroscopy of the Linac4 and superconducting proton Linac plasma generators

    SciTech Connect (OSTI)

    Lettry, J.; Kronberger, M.; Mahner, E.; Schmitzer, C.; Sanchez, J.; Scrivens, R.; Midttun, O.; O'Neil, M.; Pereira, H.; Paoluzzi, M. [European Organization for Nuclear Research, CERN, 1211 Geneva 23 (Switzerland); Fantz, U.; Wuenderlich, D. [Max-Planck-Institut fuer Plasmaphysik, IPP, 85748 Garching (Germany); Kalvas, T.; Koivisto, H.; Komppula, J.; Myllyperkioe, P.; Tarvainen, O. [Department of Physics, University of Jyvaeskylae, 40500 Jyvaeskylae (Finland)

    2012-02-15T23:59:59.000Z

    CERN's superconducting proton Linac (SPL) study investigates a 50 Hz high-energy, high-power Linac for H{sup -} ions. The SPL plasma generator is an evolution of the DESY ion source plasma generator currently operated at CERN's Linac4 test stand. The plasma generator is a step towards a particle source for the SPL, it is designed to handle 100 kW peak RF-power at a 6% duty factor. While the acquisition of an integrated hydrogen plasma optical spectrum is straightforward, the measurement of a time-resolved spectrum requires dedicated amplification schemes. The experimental setup for visible light based on photomultipliers and narrow bandwidth filters and the UV spectrometer setup are described. The H{sub {alpha}}, H{sub {beta}}, and H{sub {gamma}} Balmer line intensities, the Lyman band and alpha transition were measured. A parametric study of the optical emission from the Linac4 ion source and the SPL plasma generator as a function of RF-power and gas pressure is presented. The potential of optical emission spectrometry coupled to RF-power coupling measurements for on-line monitoring of short RF heated hydrogen plasma pulses is discussed.

  16. LT-C-ESH-LCSAD-001, Ver. 2 Linac Commissioning

    E-Print Network [OSTI]

    Ohta, Shigemi

    Source II (NSLS-II) LINAC COMMISSIONING SAFETY ASSESSMENT DOCUMENT Version 2 Submitted as partialLT-C-ESH-LCSAD-001, Ver. 2 Linac Commissioning Safety Assessment Document for the National Synchrotron Light Source II Photon Sciences Directorate Version 2 May 11, 2011 Prepared by Brookhaven National

  17. Calibration of Super-Kamiokande Using an Electron Linac

    E-Print Network [OSTI]

    The Super-Kamiokande Collaboration

    1998-07-28T23:59:59.000Z

    In order to calibrate the Super-Kamiokande experiment for solar neutrino measurements, a linear accelerator (LINAC) for electrons was installed at the detector. LINAC data were taken at various positions in the detector volume, tracking the detector response in the variables relevant to solar neutrino analysis. In particular, the absolute energy scale is now known with less than 1 percent uncertainty.

  18. Conceptual design of a superconducting high-intensity proton linac

    SciTech Connect (OSTI)

    Dominic Chan, K.C.

    1996-09-01T23:59:59.000Z

    A SCRF (superconducting RF linac) has been developed for a high-intensity proton linac which will be used as the driver for neutron sources. This design is conservative, using current SCRF technologies. As well as lowering operating cost, the design offers performance advantages in availability, beam loss, and upgradability, which are important for the application as a neutron source.

  19. Physics design of front ends for superconducting ion linacs

    SciTech Connect (OSTI)

    Ostroumov, P.N.; /Argonne; Carneiro, J.P.; /Fermilab

    2009-01-01T23:59:59.000Z

    Superconducting (SC) technology is the only option for CW linacs and is also an attractive option for pulsed linacs. SC cavities are routinely used for proton and H{sup -} beam acceleration above 185 MeV. Successful development of SC cavities covering the lower velocity range (down to 0.03c) is a very strong basis for the application of SC structures in the front ends of high energy linacs. Lattice design and related high-intensity beam physics issues in a {approx}400 MeV linac that uses SC cavities will be presented in this talk. In particular, axially-symmetric focusing by SC solenoids provides strong control of beam space-charge and a compact focusing lattice. As an example, we discuss the SC front-end of the H{sup -} linac for the FNAL Proton Driver.

  20. Physics design of front ends for superconducting ion linacs

    SciTech Connect (OSTI)

    Ostroumov, P.N.; /Argonne; Carneiro, J.-P.; /Fermilab

    2008-09-01T23:59:59.000Z

    Superconducting (SC) technology is the only option for CW linacs and is also an attractive option for pulsed linacs. SC cavities are routinely used for proton and H{sup -} beam acceleration above 185 MeV. Successful development of SC cavities covering the lower velocity range (down to 0.03c) is a very strong basis for the application of SC structures in the front ends of high energy linacs. Lattice design and related high-intensity beam physics issues in a {approx}400 MeV linac that uses SC cavities will be presented in this talk. In particular, axially-symmetric focusing by SC solenoids provides strong control of beam space charge and a compact focusing lattice. As an example, we discuss the SC front end of the H{sup -} linac for the FNAL Proton Driver.

  1. Design of the Prototypical Cryomodule for the EUROTRANS Superconducting Linac for Nuclear Waste Transmutation

    E-Print Network [OSTI]

    Barbanotti, S; Blache, P; Commeaux, C; Duthil, P; Panzeri, N; Pierini, P; Rampnoux, E; Souli, M

    2008-01-01T23:59:59.000Z

    Design of the Prototypical Cryomodule for the EUROTRANS Superconducting Linac for Nuclear Waste Transmutation

  2. PERFORMANCE OF THE DIAGNOSTICS FOR NSLS-II LINAC COMMISSIONING

    SciTech Connect (OSTI)

    Fliller III, R.; Padrazo, D.; Wang, G.M.; Heese, R.; Hseuh H.-C.; Johanson, M.; Kosciuk, B.N.; Pinayev, I.; Rose, J.; Shaftan, T.; Singh, O.

    2011-03-28T23:59:59.000Z

    The National Synchrotron Light Source II (NSLS-II) is a state of the art 3-GeV third generation light source currently under construction at Brookhaven National Laboratory. The NSLS-II injection system consists of a 200 MeV linac, a 3-GeV booster synchrotron and associated transfer lines. The transfer lines not only provide a means to deliver the beam from one machine to another, they also provide a suite of diagnostics and utilities to measure the properties of the beam to be delivered. In this paper we discuss the suite of diagnostics that will be used to commission the NSLS-II linac and measure the beam properties. The linac to booster transfer line can measure the linac emittance with a three screens measurement or a quadrupole scan. Energy and energy spread are measured in a dispersive section. Total charge and charge uniformity are measured with wall current monitors in the linac and transformers in the transfer line. We show that the performance of the diagnostics in the transfer line will be sufficient to ensure the linac meets its specifications and provides a means of trouble shooting and studying the linac in future operation.

  3. High-Performance Beam Simulator for the LANSCE Linac

    SciTech Connect (OSTI)

    Pang, Xiaoying [Los Alamos National Laboratory; Rybarcyk, Lawrence J. [Los Alamos National Laboratory; Baily, Scott A. [Los Alamos National Laboratory

    2012-05-14T23:59:59.000Z

    A high performance multiparticle tracking simulator is currently under development at Los Alamos. The heart of the simulator is based upon the beam dynamics simulation algorithms of the PARMILA code, but implemented in C++ on Graphics Processing Unit (GPU) hardware using NVIDIA's CUDA platform. Linac operating set points are provided to the simulator via the EPICS control system so that changes of the real time linac parameters are tracked and the simulation results updated automatically. This simulator will provide valuable insight into the beam dynamics along a linac in pseudo real-time, especially where direct measurements of the beam properties do not exist. Details regarding the approach, benefits and performance are presented.

  4. Development of RF linac for high-current applications

    SciTech Connect (OSTI)

    Chan, K.C.D.; Lawrence, G.P.; Schneider, J.D.

    1997-12-31T23:59:59.000Z

    High-current proton linacs are promising sources of neutrons for material processing and research applications. Recently, a linac design that makes use of a combination of normal-conducting (NC) and superconducting (SC) linac technologies has been proposed for the US Accelerator Production of Tritium Project. As a result, a multi-year engineering development and demonstration (ED and D) program is underway. In this paper, the authors will describe the design and merits of the NC/SC hybrid approach. The scope, technology issues, and present status of the ED and D Program, and the participation of industry will also be described.

  5. Energy Recovery Linacs for Light Source Applications

    SciTech Connect (OSTI)

    George Neil

    2011-04-01T23:59:59.000Z

    Energy Recovery Linacs are being considered for applications in present and future light sources. ERLs take advantage of the continuous operation of superconducting rf cavities to accelerate high average current beams with low losses. The electrons can be directed through bends, undulators, and wigglers for high brightness x ray production. They are then decelerated to low energy, recovering power so as to minimize the required rf drive and electrical draw. When this approach is coupled with advanced continuous wave injectors, very high power, ultra-short electron pulse trains of very high brightness can be achieved. This paper will review the status of worldwide programs and discuss the technology challenges to provide such beams for photon production.

  6. A Program for Optimizing SRF Linac Costs

    SciTech Connect (OSTI)

    Powers, Thomas J. [JLAB

    2013-04-01T23:59:59.000Z

    Every well-designed machine goes through the process of cost optimization several times during its design, production and operation. The initial optimizations are done during the early proposal stage of the project when none of the systems have been engineered. When a superconducting radio frequency (SRF) linac is implemented as part of the design, it is often a difficult decision as to the frequency and gradient that will be used. Frequently, such choices are made based on existing designs, which invariably necessitate moderate to substantial modifications so that they can be used in the new accelerator. Thus the fallacy of using existing designs is that they will frequently provide a higher cost machine or a machine with sub-optimal beam physics parameters. This paper describes preliminary results of a new software tool that allows one to vary parameters and understand the effects on the optimized costs of construction plus 10 year operations of an SRF linac, the associated cryogenic facility, and controls, where operations includes the cost of the electrical utilities but not the labor or other costs. It derives from collaborative work done with staff from Accelerator Science and Technology Centre, Daresbury, UK [1] several years ago while they were in the process of developing a conceptual design for the New Light Source project. The initial goal was to convert a spread sheet format to a graphical interface to allow the ability to sweep different parameter sets. The tools also allow one to compare the cost of the different facets of the machine design and operations so as to better understand the tradeoffs.

  7. Comparison of particle simulation with j-parc linac mebt beam test results

    SciTech Connect (OSTI)

    Ikegami, M.; Kato, T., Igarashi, Z.; Ueno, A.; Kondo, Y.; Ryne, R.; Qiang, J.

    2003-12-16T23:59:59.000Z

    The construction of the initial part of the J-PARC linac has been started at KEK for beam tests before moving to the JAERI Tokai campus, where J-PARC facility is finally to be constructed. The RFQ and MEBT (Medium Energy Beam Transport) has already been installed at KEK, and the beam test has been performed successfully. In this paper, the experimental results of the beam test are compared with simulation results with a 3D PIC (Particle-In-Cell) code, IMPACT.

  8. OPTICS FOR A PHOTOINJECTED ENERGY RECOVERY LINAC AT THE NSLS

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    OPTICS FOR A PHOTOINJECTED ENERGY RECOVERY LINAC AT THE NSLS * V. Yakimenko , I. Ben-Zvi, J.B. Murphy, S. Pjerov, J.H. Wu, BNL, Upton, NY 11973 USA Abstract The Photoinjected...

  9. End to End Beam Dynamics of the ESS Linac

    E-Print Network [OSTI]

    Eshraqi, M; Celona, L; Comunian, M; Danared, H; Holm, A S; Møller, S P; Ponton, A; Stovall, J; Thomsen, H D

    2012-01-01T23:59:59.000Z

    The European Spallation Source, ESS, uses a linear accelerator to deliver the high intensity proton beam to the target station. The nominal beam power is 5 MW at an energy of 2.5 GeV. The individual accelerating structures in the linac and the transport lines are brie?y described, and the beam is tracked from the source throughout the linac to the target. This paper will present a review of the beam dynamics from the source to the target.

  10. The 400 MeV Linac Upgrade at Fermilab

    SciTech Connect (OSTI)

    Noble, R.J.

    1992-12-01T23:59:59.000Z

    The Fermilab Linac Upgrade in planned to increase the energy of the H{sup {minus}} linac from 200 to 400 MeV. This is intended to reduce the incoherent space-charge tuneshift at injection into the 8 GeV Booster which limit either the brightness or the total intensity of the beam. The Linac Upgrade will be achieved by replacing the last four 201.25 MHs drift-tube linac (DTL) tanks which accelerate the beam from 116 to 200 MeV, with seven 805 MRs side-coupled cavity modules operating at an average axial field of about 7.5 MV/meter. This will allow acceleration to 400 MeV in the existing Linac enclosure. Each accelerator module will be driven with a 12 MW klystron-based rf power supply. Three of seven accelerator modules have been fabricated, power tested and installed in their temporary location adjacent to the existing DTL. All seven RF Modulators have been completed and klystron installation has begun. Waveguide runs have completed from the power supply gallery to the accelerator modules. The new linac will be powered in the temporary position without beam in order to verify overall system reliability until the laboratory operating schedule permits final conversion to 400 MeV operation.

  11. A novel electron gun for inline MRI-linac configurations

    SciTech Connect (OSTI)

    Constantin, Drago? E., E-mail: dragos.constantin@varian.com; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States)] [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Holloway, Lois [Liverpool and Macarthur Cancer Therapy Centres, The University of Sydney, NSW 2006 (Australia)] [Liverpool and Macarthur Cancer Therapy Centres, The University of Sydney, NSW 2006 (Australia); Keall, Paul J. [Radiation Physics Laboratory, The University of Sydney, NSW 2006 (Australia)] [Radiation Physics Laboratory, The University of Sydney, NSW 2006 (Australia)

    2014-02-15T23:59:59.000Z

    Purpose: This work introduces a new electron gun geometry capable of robust functioning in the presence of a high strength external magnetic field for axisymmetric magnetic resonance imaging (MRI)-linac configurations. This allows an inline MRI-linac to operate without the need to isolate the linear accelerator (linac) using a magnetic shield. This MRI-linac integration approach not only leaves the magnet homogeneity unchanged but also provides the linac flexibility to move along the magnet axis of symmetry if the source to target distance needs to be adjusted. Methods: Simple electron gun geometry modifications of a Varian 600C electron gun are considered and solved in the presence of an external magnetic field in order to determine a set of design principles for the new geometry. Based on these results, a new gun geometry is proposed and optimized in the fringe field of a 0.5 T open bore MRI magnet (GE Signa SP). A computer model for the 6 MeV Varian 600C linac is used to determine the capture efficiency of the new electron gun-linac system in the presence of the fringe field of the same MRI scanner. The behavior of the new electron gun plus the linac system is also studied in the fringe fields of two other magnets, a 1.0 T prototype open bore magnet and a 1.5 T GE Conquest scanner. Results: Simple geometrical modifications of the original electron gun geometry do not provide feasible solutions. However, these tests show that a smaller transverse cathode diameter with a flat surface and a slightly larger anode diameter could alleviate the current loss due to beam interactions with the anode in the presence of magnetic fields. Based on these findings, an initial geometry resembling a parallel plate capacitor with a hole in the anode is proposed. The optimization procedure finds a cathode-anode distance of 5 mm, a focusing electrode angle of 5°, and an anode drift tube length of 17.1 mm. Also, the linac can be displaced with ±15 cm along the axis of the 0.5 T magnet without capture efficiency reduction below the experimental value in zero field. In this range of linac displacements, the electron beam generated by the new gun geometry is more effectively injected into the linac in the presence of an external magnetic field, resulting in approximately 20% increase of the target current compared to the original gun geometry behavior at zero field. The new gun geometry can generate and accelerate electron beams in external magnetic fields without current loss for fields higher than 0.11 T. The new electron-gun geometry is robust enough to function in the fringe fields of the other two magnets with a target current loss of no more than 16% with respect to the current obtained with no external magnetic fields. Conclusions: In this work, a specially designed electron gun was presented which can operate in the presence of axisymmetric strong magnetic fringe fields of MRI magnets. Computer simulations show that the electron gun can produce high quality beams which can be injected into a straight through linac such as Varian 600C and accelerated with more efficiency in the presence of the external magnetic fields. Also, the new configuration allows linac displacements along the magnet axis in a range equal to the diameter of the imaging spherical volume of the magnet under consideration. The new electron gun-linac system can function in the fringe field of a MRI magnet if the field strength at the cathode position is higher than 0.11 T. The capture efficiency of the linac depends on the magnetic field strength and the field gradient. The higher the gradient the better the capture efficiency. The capture efficiency does not degrade more than 16%.

  12. Study of space charge-dominated beam bunching and some aspects of SSF linac designs

    SciTech Connect (OSTI)

    NONE

    1995-12-31T23:59:59.000Z

    This report is made up from works under the Agreement 1083P0015-35 between Los Alamos National Laboratory and Moscow Radiotechnical Institute. There are five report parts. In the 1-st, 2-nd, and 3-d parts works on SCD-beam dynamics understanding were continued. In the 4-th and 5-th parts two conceptual linac designs were considered: for deutron linac with energy of 40 MeV and for proton linac with energy 1 GeV. The both linacs have focusing by superconducting solenoids (SSF linacs). The 1 GeV proton CW linac design is an extension of the design from.

  13. Studies Of Coherent Synchrotron Radiation And Longitudinal Space Charge In The Jefferson Lab FEL Driver

    SciTech Connect (OSTI)

    Tennant, Christopher D. [JLAB; Douglas, David R. [JLAB; Li, Rui [JLAB; Tsai, C.-Y. [Virginia Polytechnic University

    2014-12-01T23:59:59.000Z

    The Jefferson Laboratory IR FEL Driver provides an ideal test bed for studying a variety of beam dynamical effects. Recent studies focused on characterizing the impact of coherent synchrotron radiation (CSR) with the goal of benchmarking measurements with simulation. Following measurements to characterize the beam, we quantitatively characterized energy extraction via CSR by measuring beam position at a dispersed location as a function of bunch compression. In addition to operating with the beam on the rising part of the linac RF waveform, measurements were also made while accelerating on the falling part. For each, the full compression point was moved along the backleg of the machine and the response of the beam (distribution, extracted energy) measured. Initial results of start-to-end simulations using a 1D CSR algorithm show remarkably good agreement with measurements. A subsequent experiment established lasing with the beam accelerated on the falling side of the RF waveform in conjunction with positive momentum compaction (R56) to compress the bunch. The success of this experiment motivated the design of a modified CEBAF-style arc with control of CSR and microbunching effects.

  14. Fermilab 200 MeV linac control system hardware

    SciTech Connect (OSTI)

    Shea, M.F.

    1984-01-01T23:59:59.000Z

    This report is a description of the present Linac distributed control system that replaces the original Xerox computer and interface electronics with a network of 68000-based stations. In addition to replacing the obsolete Xerox equipment, goals set for the new system were to retain the fast response and interactive nature of the original system, to improve reliability, to ease maintenance, and to provide 15 Hz monitoring of all Linac parameters. Our previous experience with microcomputer installations showed that small, stand-alone control systems are rather straightforward to implement and have been proven to be reliable in operation, even in the severe environment of the 750-keV preaccelerator. The overall design of the Linac system incorporates the concept of many relatively small, stand-alone control systems networked together using an intercomputer communication network. Each station retains its local control system character but takes advantage of the network to allow an operator to interact with the entire Linac from any local console. At the same time, a link to the central computer system allows Host computers to also access parameters in the Linac.

  15. Frequency and amplitude control for an experimental linac rf drive

    E-Print Network [OSTI]

    Atre, Mahesh Purushottam

    1992-01-01T23:59:59.000Z

    uses a RFQ accelerator/buncher to accelerate a beam of II ions. The 500 keV, 10 mA beam will require approximately 100 kW (peak) rf power at 473 MHz [2]. The basic layout of the linac system is illustrated in Fig. 1. The rf power source uses...-rod structure resonant at 473 MHz. ION SOURCE RF QUADRUPOLE BEAM HIGH POWER RF AMP AMPL CONTROL LOW POWER RF AMP OSC FREQ CONTROL SYSTEM Figure 1. The Experimental Linac System The oscillator uses a phase-locked loop for frequency control...

  16. BEAM SIMULATIONS USING VIRTUAL DIAGNOSTICS FOR THE DRIVER LINAC

    SciTech Connect (OSTI)

    R. C. York; X. Wu; Q. Zhao

    2011-12-21T23:59:59.000Z

    End-to-end beam simulations for the driver linac have shown that the design meets the necessary performance requirements including having adequate transverse and longitudinal acceptances. However, to achieve reliable operational performance, the development of appropriate beam diagnostic systems and control room procedures are crucial. With limited R&D funding, beam simulations provide a cost effective tool to evaluate candidate beam diagnostic systems and to provide a critical basis for developing early commissioning and later operational activities. We propose to perform beam dynamic studies and engineering analyses to define the requisite diagnostic systems of the driver linac and through simulation to develop and test commissioning and operational procedures.

  17. SRF cavities for CW option of Project X Linac

    SciTech Connect (OSTI)

    Solyak, N.; Gonin, I.; Khabiboulline, T.; Lunin, A.; Perunov, N.; Yakovlev, V.; /Fermilab

    2009-09-01T23:59:59.000Z

    Alternative option of Project X is based on the CW SC 2GeV Linac with the average current 1mA. Possible option of the CW Linac considered in the paper includes low energy part consisted of a few families SC Spoke cavities (from 2.5 MeV to 466 MeV) and high energy part consisted of 2 types of elliptical cavities (v/c=0.81 and v/c=1). Requirements and designed parameters of cavities are considered.

  18. New results on (LAMPF II) superconducting linac cost

    SciTech Connect (OSTI)

    Schaffer, G.

    1989-01-01T23:59:59.000Z

    A consolidated cost estimate for a superconducting 800 MeV extension of the LAMPF I linac is presented in this note. Based on recent CERN-LEP tender results for 20 superconducting cavities, the cost of a superconducting linac structure (402.5 MHz) can be projected with much better accuracy than so far. The total construction cost for an 800 MeV extension amounts to 99.5 M$, buildings, cryoplant etc. included. The corresponding figure for a normal conducting structure (1207.5 MHz, on axis coupled) is 104.6 M$.

  19. Electron contamination modeling and reduction in a 1 T open bore inline MRI-linac system

    SciTech Connect (OSTI)

    Oborn, B. M. [Illawarra Cancer Care Centre (ICCC), Wollongong, NSW 2500, Australia and Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, NSW 2500 (Australia)] [Illawarra Cancer Care Centre (ICCC), Wollongong, NSW 2500, Australia and Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, NSW 2500 (Australia); Kolling, S. [Sydney Medical School, University of Sydney, NSW 2006 (Australia)] [Sydney Medical School, University of Sydney, NSW 2006 (Australia); Metcalfe, P. E. [Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, NSW 2500, Australia and Ingham Institute for Applied Medical Research, Liverpool, NSW 2170 (Australia)] [Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, NSW 2500, Australia and Ingham Institute for Applied Medical Research, Liverpool, NSW 2170 (Australia); Crozier, S. [School of Information Technology and Electric Engineering, University of Queensland, QLD 4072 (Australia)] [School of Information Technology and Electric Engineering, University of Queensland, QLD 4072 (Australia); Litzenberg, D. W. [Department of Radiation Oncology, University of Michigan Hospital and Health Systems, Ann Arbor, Michigan 48109 (United States)] [Department of Radiation Oncology, University of Michigan Hospital and Health Systems, Ann Arbor, Michigan 48109 (United States); Keall, P. J. [Sydney Medical School, University of Sydney, NSW 2006, Australia and Ingham Institute for Applied Medical Research, Liverpool, NSW 2170 (Australia)] [Sydney Medical School, University of Sydney, NSW 2006, Australia and Ingham Institute for Applied Medical Research, Liverpool, NSW 2170 (Australia)

    2014-05-15T23:59:59.000Z

    Purpose: A potential side effect of inline MRI-linac systems is electron contamination focusing causing a high skin dose. In this work, the authors reexamine this prediction for an open bore 1 T MRI system being constructed for the Australian MRI-Linac Program. The efficiency of an electron contamination deflector (ECD) in purging electron contamination from the linac head is modeled, as well as the impact of a helium gas region between the deflector and phantom surface for lowering the amount of air-generated contamination. Methods: Magnetic modeling of the 1 T MRI was used to generate 3D magnetic field maps both with and without the presence of an ECD located immediately below the MLC’s. Forty-seven different ECD designs were modeled and for each the magnetic field map was imported into Geant4 Monte Carlo simulations including the linac head, ECD, and a 30 × 30 × 30 cm{sup 3} water phantom located at isocenter. For the first generation system, the x-ray source to isocenter distance (SID) will be 160 cm, resulting in an 81.2 cm long air gap from the base of the ECD to the phantom surface. The first 71.2 cm was modeled as air or helium gas, with the latter encased between two windows of 50 ?m thick high density polyethlyene. 2D skin doses (at 70 ?m depth) were calculated across the phantom surface at 1 × 1 mm{sup 2} resolution for 6 MV beams of field size of 5 × 5, 10 × 10, and 20 × 20 cm{sup 2}. Results: The skin dose was predicted to be of similar magnitude as the generic systems modeled in previous work, 230% to 1400% ofD {sub max} for 5 × 5 to 20 × 20 cm{sup 2}, respectively. Inclusion of the ECD introduced a nonuniformity to the MRI imaging field that ranged from ?20 to ?140 ppm while the net force acting on the ECD ranged from ?151 N to ?1773 N. Various ECD designs were 100% efficient at purging the electron contamination into the ECD magnet banks; however, a small percentage were scattered back into the beam and continued to the phantom surface. Replacing a large portion of the extended air-column between the ECD and phantom surface with helium gas is a key element as it significantly minimized the air-generated contamination. When using an optimal ECD and helium gas region, the 70 ?m skin dose is predicted to increase moderately inside a small hot spot over that of the case with no magnetic field present for the jaw defined square beams examined here. These increases include from 12% to 40% of D {sub max} for 5 × 5 cm{sup 2}, 18% to 55% of D {sub max} for 10 × 10 cm{sup 2}, and from 23% to 65% of D {sub max} for 20 × 20 cm{sup 2}. Conclusions: Coupling an efficient ECD and helium gas region below the MLCs in the 160 cm isocenter MRI-linac system is predicted to ameliorate the impact electron contamination focusing has on skin dose increases. An ECD is practical as its impact on the MRI imaging distortion is correctable, and the mechanical forces acting on it manageable from an engineering point of view.

  20. Linac Coherent Light Source (LCLS) | U.S. DOE Office of Science...

    Office of Science (SC) Website

    Syncrotron Light Source (NSLS-II) Stanford Synchrotron Radiation Light Source (SSRL) Neutron Scattering Facilities Nanoscale Science Research Centers (NSRCs) Projects...

  1. The Soft X-ray research instrument at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dakovski, Georgi L.; Heimann, Philip; Holmes, Michael; Krupin, Oleg; Minitti, Michael P.; Mitra, Ankush; Moeller, Stefan; Rowen, Michael; Schlotter, William F.; Turner, Joshua J.

    2015-05-01T23:59:59.000Z

    The Soft X-ray Research instrument provides intense ultrashort X-ray pulses in the energy range 280–2000 eV. A diverse set of experimental stations may be installed to investigate a broad range of scientific topics such as ultrafast chemistry, highly correlated materials, magnetism, surface science, and matter under extreme conditions. A brief description of the main instrument components will be given, followed by some selected scientific highlights.

  2. The matter in extreme conditions instrument at the Linac Coherent Light Source

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Nagler, Bob; Arnold, Brice; Bouchard, Gary; Boyce, Richard F.; Boyce, Richard M.; Callen, Alice; Campell, Marc; Curiel, Ruben; Galtier, Eric; Garofoli, Justin; et al

    2015-05-01T23:59:59.000Z

    The LCLS beam provides revolutionary capabilities for studying the transient behavior of matter in extreme conditions. The particular strength of the Matter in Extreme Conditions instrument is that it combines the unique LCLS beam with high-power optical laser beams, and a suite of dedicated diagnostics tailored for this field of science. In this paper an overview of the beamline, the capabilities of the instrumentation, and selected highlights of experiments and commissioning results are presented.

  3. The Physics of the Gas Attenuator for the Linac Coherent Light Source (LCLS)

    SciTech Connect (OSTI)

    Ryutov, D.D.; Bionta, R.M.; Hau-Riege, S.P.; Kishiyama, K.I.; McMahon, D.; Roeben, M.D.; Shen, S.; /LLNL, Livermore; Stefan, P.M.; /SLAC; ,

    2011-02-07T23:59:59.000Z

    A systematic assessment of a variety of physics issues affecting the performance of the LCLS X-ray beam attenuator is presented. Detailed analysis of the gas flow in the gas attenuator and in the apertures is performed. A lot of attention is directed towards the gas ionization and heating by intense X-ray pulses. The role of these phenomena in possible deviations of the attenuation coefficient from its 'dialed in' value is evaluated and found small in most cases. Other sources of systematic and statistical errors are also discussed. The regimes where the errors may reach a few percent correspond to the lower X-ray energies (less than 2 keV) and highest beam intensities. Other effects discussed include chemical interaction of the gas with apertures, shock formation in the transonic flow in the apertures of the attenuator, generation of electromagnetic wakes in the gas, and head-to-tail variation of the attenuation caused by the ionization of gas or solid. Possible experimental tests of the consistency of the physics assumptions used in the concept of the gas attenuator are discussed. Interaction of X-rays with the solid attenuator (that will be used at higher X-ray energies, from 2.5 to 8 keV) is considered and thermo-mechanical effects caused by the beam heating are evaluated. Wave-front distortions induced by non-uniform heating of both the solid and the gas are found to be small. An overall conclusion drawn from the analysis presented is that the attenuator will be a reliable and highly versatile device, provided that some caution is exercised in its use for highest beam intensities at lowest X-ray energies.

  4. EA-1975: LINAC Coherent Light Source-Il, SLAC National Accelerator...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    the photon energy range, increase control over photon pulses, and enable two-color pump-probe experiments. The X-ray laser beams generated by LCLS-II would enable a new class...

  5. User 'To Do' List after Beam Time is Assigned | Linac Coherent Light Source

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrinceton PlasmaAfternoon4. UraniumUsed FuelFAQ » Useful Links'To

  6. Linac Coherent Light Source (LCLS) | U.S. DOE Office of Science (SC)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5Let us countLighting SignLiisaLin Wang Lin

  7. Generation of Coherent X-Ray Radiation Through Modulation Compression

    E-Print Network [OSTI]

    Qiang, Ji

    2010-01-01T23:59:59.000Z

    In this letter, we propose a scheme to generate tunable coherent X-ray radiation for future light source applications. This scheme uses an energy chirped electron beam, a laser modulators, a laser chirper and two bunch compressors to generate a prebunched kilo-Ampere current electron beam from a few tens Ampere electron beam out of a linac. The initial modulation energy wavelength can be compressed by a factor of $1+h_b R_{56}^a$ in phase space, where $h_b$ is the energy bunch length chirp introduced by the laser chirper, $R_{56}^a$ is the momentum compaction factor of the first bunch compressor. As an illustration, we present an example to generate more than $400$ MW, $170$ atto-seconds pulse, $1$ nm coherent X-ray radiation using a $60$ Ampere electron beam out of the linac and $200$ nm laser seed. Both the final wavelength and the radiation pulse length in the proposed scheme are tunable by adjusting the compression factor and the laser parameters.

  8. Generation of Coherent X-Ray Radiation Through Modulation Compression

    SciTech Connect (OSTI)

    Qiang, Ji; Wu, Juhao

    2010-12-14T23:59:59.000Z

    In this letter, we propose a scheme to generate tunable coherent X-ray radiation for future light source applications. This scheme uses an energy chirped electron beam, a laser modulators, a laser chirper and two bunch compressors to generate a prebunched kilo-Ampere current electron beam from a few tens Ampere electron beam out of a linac. The initial modulation energy wavelength can be compressed by a factor of 1 + h{sub b}R{sub 56}{sup a} phase space, where h{sub b} is the energy bunch length chirp introduced by the laser chirper, R{sub 56}{sup a} is the momentum compaction factor of the first bunch compressor. As an illustration, we present an example to generate more than 400 MW, 170 atto-seconds pulse, 1 nm coherent X-ray radiation using a 60 Ampere electron beam out. of the linac and 200 nm laser seed. Both the final wavelength and the radiation pulse length in the proposed scheme are tunable by adjusting the compression factor and the laser parameters.

  9. Challenges to the Fermilab linac and booster accelerators

    SciTech Connect (OSTI)

    Robert C. Webber

    2001-07-12T23:59:59.000Z

    A report on the challenges confronting the Fermilab Linac and Booster accelerators is presented. Plans to face those challenges are discussed. Historically, the Linac/Booster system has served only as an injector for the relatively low repetition rate Main Ring synchrotron. With construction of an 8 GeV target station for the 5 Hz MiniBooNE neutrino beam and requirements for rapid multi-batch injection into the Main Injector for the NUMI/MINOS experiment, the demand for 8 GeV protons will increase more than an order of magnitude above recent high levels. To meet this challenge, enhanced ion source performance, better Booster orbit control, a beam loss collimation/localization system, and improved diagnostics are among the items being pursued. Booster beam loss reduction and control are key to the entire near future Fermilab high energy physics program.

  10. Linac4 low energy beam measurements with negative hydrogen ions

    SciTech Connect (OSTI)

    Scrivens, R., E-mail: richard.scrivens@cern.ch; Bellodi, G.; Crettiez, O.; Dimov, V.; Gerard, D.; Granemann Souza, E.; Guida, R.; Hansen, J.; Lallement, J.-B.; Lettry, J.; Lombardi, A.; Midttun, Ø.; Pasquino, C.; Raich, U.; Riffaud, B.; Roncarolo, F.; Valerio-Lizarraga, C. A.; Wallner, J.; Yarmohammadi Satri, M.; Zickler, T. [CERN, 1211 Geneva 23 (Switzerland)] [CERN, 1211 Geneva 23 (Switzerland)

    2014-02-15T23:59:59.000Z

    Linac4, a 160 MeV normal-conducting H{sup ?} linear accelerator, is the first step in the upgrade of the beam intensity available from the LHC proton injectors at CERN. The Linac4 Low Energy Beam Transport (LEBT) line from the pulsed 2 MHz RF driven ion source, to the 352 MHz RFQ (Radiofrequency Quadrupole) has been built and installed at a test stand, and has been used to transport and match to the RFQ a pulsed 14 mA H{sup ?} beam at 45 keV. A temporary slit-and-grid emittance measurement system has been put in place to characterize the beam delivered to the RFQ. In this paper a description of the LEBT and its beam diagnostics is given, and the results of beam emittance measurements and beam transmission measurements through the RFQ are compared with the expectation from simulations.

  11. Linac4 Low Energy Beam Measurements with Negative Hydrogen

    E-Print Network [OSTI]

    Scrivens, R; Crettiez, O; Dimov, V; Gerard, D; Granemann Souza, E; Guida, R; Hansen, J; Lallement, J B; Lettry, J; Lombardi, A; Midttun, O; Pasquino, C; Raich, U; Riffaud, B; Roncarolo, F; Valerio-Lizarraga, C A; Wallner, J; Yarmohammadi Satri, M; Zickler, T

    2013-01-01T23:59:59.000Z

    Linac4, a 160 MeV normal-conducting H- linear accelerator, is the first step in the upgrade of the beam intensity available from the LHC proton injectors at CERN. The Linac4 Low Energy Beam Transport (LEBT) line from the pulsed 2 MHz RF driven ion source, to the 352 MHz RFQ has been built and installed at a test stand, and has been used to transport and match to the RFQ a pulsed 14 mA H- beam at 45 keV. A temporary slit-and-grid emittance measurement system has been put in place to characterize the beam delivered to the RFQ. In this paper a description of the LEBT and its beam diagnostics is given, and the results of beam emittance measurements and beam transmission measurements through the RFQ are compared with the expectation from simulations.

  12. Linac-Based Proton Driver for a Neutrino Factory

    E-Print Network [OSTI]

    Garoby, R; Aiba, M; Meddahi, M

    2009-01-01T23:59:59.000Z

    A Neutrino Factory Proton Driver based on a superconducting proton linac has been designed in the CERN context. The 5 GeV/4 MW H- beam from the linac is accumulated using charge exchange injection in a fixed-energy synchrotron and afterwards transferred to a compressor ring, where bunch rotation takes place. The lattices of the accumulator and compressor are described, as well as magnet technology and RF manipulations. Critical issues related to charge-exchange injection, space-charge effects in the compressor and beam stability in the accumulator, are addressed. The analysis is focused on the baseline scenario, which provides 6 bunches on the target. Results of preliminary analysis of options with less bunches (three and one) are also presented.

  13. Design of a Marx-Topology Modulator for FNAL Linac

    E-Print Network [OSTI]

    Butler, T A; Kufer, M R; Pfeffer, H; Wolff, D

    2015-01-01T23:59:59.000Z

    The Fermilab Proton Improvement Plan (PIP) was formed in late 2011 to address important and necessary upgrades to the Proton Source machines (Injector line, Linac and Booster). The goal is to increase the proton flux by doubling the Booster beam cycle rate while maintaining the same intensity per cycle, the same uptime, and the same residual activation in the enclosure. For the Linac, the main focus within PIP is to address reliability. One of the main tasks is to replace the present hard-tube modulator used on the 200 MHz RF system. Plans to replace this high power system with a Marx-topology modulator, capable of providing the required waveform shaping to stabilize the accelerating gradient and compensate for beam loading, will be presented, along with development data from the prototype unit.

  14. Three-dimensional simulation of coherent inverse Compton scattering

    E-Print Network [OSTI]

    Resta, Giacomo Rosario

    2014-01-01T23:59:59.000Z

    Novel compact X-ray sources using coherent ICS have the potential to positively impact a wide range of sectors by making hard x-ray techniques more accessible. However, the analysis of such novel sources requires improvements ...

  15. HIGH DYNAMIC-RANGE HIGH SPEED LINAC CURRENT MEASUREMENTS

    SciTech Connect (OSTI)

    Deibele, Craig Edmond [ORNL] [ORNL; Curry, Douglas E [ORNL] [ORNL; Dickson, Richard W [ORNL] [ORNL

    2012-01-01T23:59:59.000Z

    It is desired to measure the linac current of a charged particle beam with a consistent accuracy over a dynamic range of over 120 dB. Conventional current transformers suffer from droop, can be susceptible to electromagnetic interference (EMI), and can be bandwidth limited. A novel detector and electronics were designed to maximize dynamic range of about 120 dB and measure rise-times on the order of 10 nanoseconds.

  16. Status and operation of the Linac4 ion source prototypes

    SciTech Connect (OSTI)

    Lettry, J., E-mail: Jacques.lettry@cern.ch; Aguglia, D.; Andersson, P.; Bertolo, S.; Butterworth, A.; Coutron, Y.; Dallocchio, A.; Chaudet, E.; Gil-Flores, J.; Guida, R.; Hansen, J.; Koszar, I.; Mahner, E.; Mastrostefano, C.; Mathot, S.; Mattei, S.; Midttun, Ø.; Moyret, P.; Nisbet, D.; O’Neil, M. [CERN, 1211 Geneva 23 (Switzerland)] [CERN, 1211 Geneva 23 (Switzerland); and others

    2014-02-15T23:59:59.000Z

    CERN's Linac4 45 kV H{sup ?} ion sources prototypes are installed at a dedicated ion source test stand and in the Linac4 tunnel. The operation of the pulsed hydrogen injection, RF sustained plasma, and pulsed high voltages are described. The first experimental results of two prototypes relying on 2 MHz RF-plasma heating are presented. The plasma is ignited via capacitive coupling, and sustained by inductive coupling. The light emitted from the plasma is collected by viewports pointing to the plasma chamber wall in the middle of the RF solenoid and to the plasma chamber axis. Preliminary measurements of optical emission spectroscopy and photometry of the plasma have been performed. The design of a cesiated ion source is presented. The volume source has produced a 45 keV H{sup ?} beam of 16–22 mA which has successfully been used for the commissioning of the Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ) accelerator, and chopper of Linac4.

  17. High-brightness beam diagnostics for the APS linac.

    SciTech Connect (OSTI)

    Lumpkin, A. H.

    1999-04-20T23:59:59.000Z

    The Advanced Photon Source (APS) injector includes an S-band linac with the capability to accelerate beams to 650 MeV. The linac has recently been upgraded with the installation of an rf thermionic gun in addition to the standard DC thermionic gun. The rf gun is predicted to have lower emittance (5{pi}mm mrad) and may be used to support the APS self-amplified spontaneous emission (SASE) experiments. The critical characterization of this gun's beam has begun with a beam diagnostics station at the end of the linac that can address beam transverse size, emittance, and bunch length (peak current). This station uses both an optical transition radiation (OTR) screen at 45{degree} to the beam direction and a Ce-doped YAG single crystal normal to the beam with a 45{degree} mirror behind it. The visible light images are detected by a Vicon CCD camera and a Hamamatsu C5680 synchroscan streak camera. Spatial resolution of about 30 {micro}m ({sigma}) and temporal resolution of 1 ps ({sigma}) have been demonstrated. Examples of rf gun beam characterization at 220 MeV are reported.

  18. Recent improvements to software used for optimization of SRF linacs

    SciTech Connect (OSTI)

    Powers, Tom J. [JLAB

    2014-12-01T23:59:59.000Z

    This work describes a software tool that allows one to vary parameters and understand the effects on the optimized costs of construction plus 10 year operations of an SRF linac, where operation costs includes the cost of the electrical utilities but not the labor or other costs. The program includes estimates for the associated cryogenic facility, and controls hardware. The software interface provides the ability to vary the cost of the different aspects of the machine as well as to change the cryomodule and cavity types. Additionally, this work will describe the recent improvements to the software that allow one to estimate the costs of energy-recovery based linacs and to enter arbitrary values of the low field Q0 and Q0 slope. The initial goal when developing the software was to convert a spreadsheet format to a graphical interface and to allow the ability to sweep different parameter sets. The tools also allow one to compare the cost of the different facets of the machine design and operations so as to better understand tradeoffs. An example of how it was used to independently investigate cost optimization tradeoffs for the LCLS-II linac will also be presented.

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

    SciTech Connect (OSTI)

    Carneiro, J.-P.; /Fermilab; Mustapha, B.; Ostroumov, P.N.; /Argonne

    2008-12-01T23:59:59.000Z

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

  20. Coherent Synchrotron Radiation Analysis

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Upton, NY 11973, USA Abstract Coherent Synchrotron Radiation (CSR) effects in bunch compressors are analyzed. Schemes for reducing the CSR effects are presented. 1 INTRODUCTION...

  1. Single-cycle terahertz pulses with >0.2 V/A field amplitudes via coherent transition radiation

    SciTech Connect (OSTI)

    Daranciang, Dan [Department of Chemistry, Stanford University, Stanford, California 94305 (United States); PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Goodfellow, John [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Fuchs, Matthias; Ghimire, Shambhu [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Wen, Haidan [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Reis, David A. [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Loos, Henrik; Fisher, Alan S. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Lindenberg, Aaron M. [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

    2011-10-03T23:59:59.000Z

    We demonstrate terahertz pulses with field amplitudes exceeding 0.2 V/A generated by coherent transition radiation. Femtosecond, relativistic electron bunches generated at the Linac Coherent Light Source are passed through a beryllium foil, and the emitted radiation is characterized as a function of the bunch duration and charge. Broadband pulses centered at a frequency of 10 THz with energies of 140 {mu}J are measured. These far-below-bandgap pulses drive a nonlinear optical response in a silicon photodiode, with which we perform nonlinear autocorrelations that yield information regarding the terahertz temporal profile. Simulations of the spatiotemporal profile agree well with experimental results.

  2. Focus characterization at an X-ray free-electron laser by coherent scattering and speckle analysis

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sikorski, Marcin; Song, Sanghoon; Schropp, Andreas; Seiboth, Frank; Feng, Yiping; Alonso-Mori, Roberto; Chollet, Matthieu; Lemke, Henrik T.; Sokaras, Dimosthenis; Weng, Tsu-Chien; et al

    2015-05-01T23:59:59.000Z

    X-ray focus optimization and characterization based on coherent scattering and quantitative speckle size measurements was demonstrated at the Linac Coherent Light Source. Its performance as a single-pulse free-electron laser beam diagnostic was tested for two typical focusing configurations. The results derived from the speckle size/shape analysis show the effectiveness of this technique in finding the focus' location, size and shape. In addition, its single-pulse compatibility enables users to capture pulse-to-pulse fluctuations in focus properties compared with other techniques that require scanning and averaging.

  3. High Current Energy Recovery Linac at BNL | U.S. DOE Office of...

    Office of Science (SC) Website

    High Current Energy Recovery Linac at BNL Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Applications of Nuclear Science Applications of...

  4. Energy Recovery Linac cavity at BNL | U.S. DOE Office of Science...

    Office of Science (SC) Website

    Energy Recovery Linac cavity at BNL Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Applications of Nuclear Science Applications of Nuclear...

  5. Instrumentation and Diagnostics for High Repetition Rate LINAC-Driven FEL

    E-Print Network [OSTI]

    De Santis, S

    2014-01-01T23:59:59.000Z

    Evtushenko, “Electron Beam Diagnostics For High Current FELDrivers”, FEL 2011, Shanghai (2011). [5] F. Sannibale, etREPETITION RATE LINAC-DRIVEN FEL S. De Santis # , J. Byrd,

  6. SU-E-J-239: IMRT Planning of Prostate Cancer for a MRI-Linac Based On MRI Only

    SciTech Connect (OSTI)

    Chen, X; Prior, P; Paulson, E; Lawton, C; Li, X [Medical College of Wisconsin, Milwaukee, WI (United States)

    2014-06-01T23:59:59.000Z

    Purpose: : To investigate dosimetric differences between MRI- and CT-based IMRT planning for prostate cancer, the impact of a magnetic field in a MRI-Linac, and to explore the feasibility of IMRT planning based on MRI alone. Methods: IMRT plans were generated based on CT and MRI images acquired on two representative prostate-cancer patients using clinical dose volume constraints. A research planning system (Monaco, Elekta), which employs a Monte Carlo dose engine and includes a perpendicular magnetic field of 1.5T from an MRI-Linac, was used. Bulk electron density assignments based on organ-specific values from ICRU 46 were used to convert MRI (T2) to pseudo CT. With the same beam configuration as in the original CT plan, 5 additional plans were generated based on CT or MRI, with or without optimization (i.e., just recalculation) and with or without the magnetic field. The plan quality in terms of commonly used dose volume (DV) parameters for all plans was compared. The statistical uncertainty on dose was < 1%. Results: For plans with the same contour set but without re-optimization, the DV parameters were different from those for the original CT plan, mostly less than 5% with a few exceptions. These differences were reduced to mostly less than 3% when the plans were re-optimized. For plans with contours from MRI, the differences in the DV parameters varied depending on the difference in the contours as compared to CT. For the optimized plans with contours from MR, the differences for PTV were less than 3%. Conclusion: The prostate IMRT plans based on MRI-only for a MR-Linac were practically similar as compared to the CT plan under the same beam and optimization configuration if the difference on the structure delineation is excluded, indicating the feasibility of using MRI-only for prostate IMRT.

  7. SC Beta Graded Cavity Design for a Proposed 350 MHZ Linac for Waste Transmutation and Energy Production

    E-Print Network [OSTI]

    Barni, D; Pagani, C; Pierini, P; Visona, S; Gemme, G; Parodi, R

    1998-01-01T23:59:59.000Z

    SC Beta Graded Cavity Design for a Proposed 350 MHZ Linac for Waste Transmutation and Energy Production

  8. Positron-production Experiment In Tungsten Crystal Using 4 And 8-gev Channeling Electrons At The Kekb Injector Linac

    E-Print Network [OSTI]

    Suwada, T; Chehab, R; Enomoto, A; Furukawa, K; Kakihara, K; Kamitani, T; Ogawa, Y; Ohsawa, S; Okuno, H; Oogoe, T; Fujita, T; Umemori, K; Yoshida, K; Ababiy, V; Potylitsin, A P; Vnukov, I E; Hamatsu, R; Sasahara, K

    2002-01-01T23:59:59.000Z

    Positron-production Experiment In Tungsten Crystal Using 4 And 8-gev Channeling Electrons At The Kekb Injector Linac

  9. Positron-production Experiment By 8-gev Channeling Electrons In Crystal Tungsten At The Kekb Injector Linac

    E-Print Network [OSTI]

    Suwada, T

    2001-01-01T23:59:59.000Z

    Positron-production Experiment By 8-gev Channeling Electrons In Crystal Tungsten At The Kekb Injector Linac

  10. Status of the TESLA Test Facility Linac H. Weise, for the TESLA Collaboration

    E-Print Network [OSTI]

    Status of the TESLA Test Facility Linac H. Weise, for the TESLA Collaboration Deutsches Elektronen-Synchrotron DESY D-22603 Hamburg, Germany Abstract The TTF linac, a major effort of the TESLA Test Facility, is now GeV collider is the usage of superconducting (s.c.) accelerating structures. The international TESLA

  11. PERFORMANCE STATUS OF THE RF-GUN BASED INJECTOR OF THE TESLA TEST FACILITY LINAC

    E-Print Network [OSTI]

    PERFORMANCE STATUS OF THE RF-GUN BASED INJECTOR OF THE TESLA TEST FACILITY LINAC S. Schreiber£ for the TESLA Collaboration, DESY, 22603 Hamburg, Germany Abstract The TESLA Test Facility Linac (TTFL) at DESY uses two modules with 8 TESLA superconducting accelerat- ing structures each to accelerate an electron

  12. PERFORMANCE OF THE TESLA TEST FACILITY LINAC for the TESLA Collaboration

    E-Print Network [OSTI]

    PERFORMANCE OF THE TESLA TEST FACILITY LINAC P. Castro for the TESLA Collaboration Abstract In order to test the performance of a superconducting linac, the TESLA Collaboration has built and operated for the TESLA design. Results of recent running periods will be summarized in this paper. 1 INTRODUCTION

  13. FIRST EXPERIMENTS WITH THE RF GUN BASED INJECTOR FOR THE TESLA TEST FACILITY LINAC

    E-Print Network [OSTI]

    FIRST EXPERIMENTS WITH THE RF GUN BASED INJECTOR FOR THE TESLA TEST FACILITY LINAC S. Schreiber for the TESLA Collaboration, DESY, 22603 Hamburg, Germany Abstract During 1997 and 1998 a first accelerator module was tested successfully at the TESLA Test Facility Linac (TTFL) at DESY. Eight superconducting

  14. File system, SaveRestore and Sequencer for LINAC2, DESY2, PETRA3 and FLASH,

    E-Print Network [OSTI]

    File system, SaveRestore and Sequencer for LINAC2, DESY2, PETRA3 and FLASH, a status report Jürgen 4 #12;Basic principle of "Machine file system" disk save rings linacs · `set points' · `read-back' values · position Quads · position Beam · etc. machine file restore More features: ·compare: between file

  15. 1Mechanical, Aerospace and Nuclear Engineering nacThe Gaerttner Laboratory RPI LINAC Facility

    E-Print Network [OSTI]

    Danon, Yaron

    Nuclear Criticality Safety Program Conference April 27, 2011 #12;2Mechanical, Aerospace and Nuclear, Aerospace and Nuclear Engineering nacThe Gaerttner Laboratory RPI LINAC Facility Nuclear Criticality Safety1Mechanical, Aerospace and Nuclear Engineering nacThe Gaerttner Laboratory RPI LINAC Facility

  16. TESLA-FEL Report 2004-08 LINAC BASED FREE-ELECTRON LASER

    E-Print Network [OSTI]

    TESLA-FEL Report 2004-08 1 LINAC BASED FREE-ELECTRON LASER J. Rossbach Universität Hamburg, Hamburg, Germany Abstract A basic treatment of the principle of the linac-driven free-electron laser (FEL) is given. The first part of the paper describes the FEL in low-gain approximation, and in the second part the high

  17. HIGH INTENSITY LINAC DRIVER FOR THE SPIRAL-2 PROJECT : DESIGN OF SUPERCONDUCTING 88 MHZ QUARTER WAVE

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    . For the high-energy section of the linac, a superconducting 88 MHz Quarter Wave Resonator (beta 0.12) has been WAVE RESONATORS (BETA 0.12), POWER COUPLERS AND CRYOMODULES T. Junquera, G. Olry, H. Saugnac, J Abstract A superconducting linac driver, delivering deuterons with an energy up to 40 MeV (5 mA) and heavy

  18. Large dynamic range diagnostics for high current electron LINACs

    SciTech Connect (OSTI)

    Evtushenko, P., E-mail: Pavel.Evtushenko@jlab.org [Thomas Jefferson National Accelerator Facility 12000 Jefferson Avenue, Newport News, VA 23606 (United States)

    2013-11-07T23:59:59.000Z

    The Jefferson Lab FEL driver accelerator - Energy Recovery Linac has provided a beam with average current of up to 9 mA and beam energy of 135 MeV. The high power beam operations have allowed developing and testing methods and approaches required to set up and tune such a facility simultaneously for the high beam power and high beam quality required for high performance FEL operations. In this contribution we briefly review this experience and outline problems that are specific to high current - high power non-equilibrium linac beams. While the original strategy for beam diagnostics and tuning have proven to be quite successful, some shortcomings and unresolved issues were also observed. The most important issues are the non-equilibrium (non-Gaussian) nature of the linac beam and the presence of small intensity - large amplitude fraction of the beam a.k.a. beam halo. Thus we also present a list of the possible beam halo sources and discuss possible mitigations means. We argue that for proper understanding and management of the beam halo large dynamic range (>10{sup 6}) transverse and longitudinal beam diagnostics can be used. We also present results of transverse beam profile measurements with the dynamic range approaching 10{sup 5} and demonstrate the effect the increased dynamic range has on the beam characterization, i.e., emittance and Twiss parameters measurements. We also discuss near future work planned in this field and where the JLab FEL facility will be used for beam tests of the developed of new diagnostics.

  19. Much Ado about Microbunching: Coherent Bunching in High Brightness Electron Beams

    SciTech Connect (OSTI)

    Ratner, Daniel; /Stanford U. /SLAC

    2012-05-25T23:59:59.000Z

    The push to provide ever brighter coherent radiation sources has led to the creation of correspondingly bright electron beams. With billions of electrons packed into normalized emittances (phase space) below one micron, collective effects may dominate both the preservation and use of such ultra-bright beams. An important class of collective effects is due to density modulations within the bunch, or microbunching. Microbunching may be deleterious, as in the case of the Microbunching Instability (MBI), or it may drive radiation sources of unprecedented intensity, as in the case of Free Electron Lasers (FELs). In this work we begin by describing models of microbunching due to inherent beam shot noise, which sparks both the MBI as well as SLAC's Linac Coherent Light Source, the world's first hard X-ray laser. We first use this model to propose a mechanism for reducing the inherent beam shot noise as well as for predicting MBI effects. We then describe experimental measurements of the resulting microbunching at LCLS, including optical radiation from the MBI, as well as the first gain length and harmonic measurements from a hard X-ray FEL. In the final chapters, we describe schemes that use external laser modulations to microbunch light sources of the future. In these sections we describe coherent light source schemes for both both linacs and storage rings.

  20. Compensating effect of the coherent synchrotron radiation in bunch compressors

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jing, Yichao; Hao, Yue; Litvinenko, Vladimir N.

    2013-06-01T23:59:59.000Z

    Typical bunch compression for a high-gain free-electron laser (FEL) requires a large compression ratio. Frequently, this compression is distributed in multiple stages along the beam transport line. However, for a high-gain FEL driven by an energy recovery linac (ERL), compression must be accomplished in a single strong compressor located at the beam line’s end; otherwise the electron beam would be affected severely by coherent synchrotron radiation (CSR) in the ERL’s arcs. In such a scheme, the CSR originating from the strong compressors could greatly degrade the quality of the electron beam. In this paper, we present our design for a bunch compressor that will limit the effect of CSR on the e-beam’s quality. We discuss our findings from a study of such a compressor, and detail its potential for an FEL driven by a multipass ERL developed for the electron-Relativistic Heavy Ion Collider.

  1. Linac cryogenic distribution system maintenance and upgrades at JLab

    SciTech Connect (OSTI)

    Dixon, K.; Wright, M.; Ganni, V. [Thomas Jefferson National Accelerator Facility (JLab), Newport News, VA 23606 (United States)

    2014-01-29T23:59:59.000Z

    The Central Helium Liquefier (CHL) distribution system to the CEBAF and FEL linacs at Jefferson Lab (JLab) experienced a planned warm up during the late summer and fall of 2012 for the first time after its commissioning in 1991. Various maintenance and modifications were performed to support high beam availability to the experimental users, meet 10 CFR 851 requirements for pressure systems, address operational issues, and prepare the cryogenic interfaces for the high-gradient cryomodules needed for the 12 GeV upgrade. Cryogenic maintenance and installation work had to be coordinated with other activities in the linacs and compete for manpower from other department installation activities. With less than a quarter of the gas storage capacity available to handle the boil-off from the more than 40 cryomodules, 35,000 Nm{sup 3} of helium was re-liquefied and shipped to a vendor via a liquid tanker trailer. Nearly 200 u-tubes had to be removed and stored while seals were replaced on related equipment such as vacuum pump outs, bayonet isolation and process valves.

  2. Linac cryogenic distribution system maintenance and upgrades at Jlab

    SciTech Connect (OSTI)

    Dixon, Kelly D. [JLAB; Wright, Mathew C. [JLAB; Ganni, Venkatarao [JLAB

    2014-01-01T23:59:59.000Z

    The Central Helium Liquefier (CHL) distribution system to the CEBAF and FEL linacs at Jefferson Lab (JLab) experienced a planned warm up during the late summer and fall of 2012 for the first time after its commissioning in 1991. Various maintenance and modifications were performed to support high beam availability to the experimental users, meet 10 CFR 851 requirements for pressure systems, address operational issues, and prepare the cryogenic interfaces for the high-gradient cryomodules needed for the 12 GeV upgrade. Cryogenic maintenance and installation work had to be coordinated with other activities in the linacs and compete for manpower from other department installation activities. With less than a quarter of the gas storage capacity available to handle the boil-off from the more than 40 cryomodules, 35,000 Nm{sup 3} of helium was re-liquefied and shipped to a vendor via a liquid tanker trailer. Nearly 200 u-tubes had to be removed and stored while seals were replaced on related equipment such as vacuum pump outs, bayonet isolation and process valves.

  3. SRF photoinjector for proof-of-principle experiment of coherent electron cooling at RHIC

    SciTech Connect (OSTI)

    Kayran D.; Belomestnykh, S.; Ben-Zvi, I.; Brutus, J.C.; et al

    2012-05-20T23:59:59.000Z

    Coherent Electron Cooling (CEC) based on Free Electron Laser (FEL) amplifier promises to be a very good way to cool protons and ions at high energies. A proof of principle experiment to demonstrate cooling at 40 GeV/u is under construction at BNL. One of possible sources to provide sufficient quality electron beam for this experiment is a SRF photoinjector. In this paper we discuss design and simulated performance of the photoinjector based on existing 112 MHz SRF gun and newly designed single-cavity SRF linac operating at 704 MHz.

  4. Nuclear Data Measurements at the RPI LINAC Y. Danon, R.C. Block, R. Bahran, M. Rapp, F. Saglime, C. Romano, J. Thompson

    E-Print Network [OSTI]

    Danon, Yaron

    . Romano, J. Thompson Gaerttner LINAC Laboratory, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA D

  5. SAR image effects on coherence and coherence estimation.

    SciTech Connect (OSTI)

    Bickel, Douglas Lloyd

    2014-01-01T23:59:59.000Z

    Radar coherence is an important concept for imaging radar systems such as synthetic aperture radar (SAR). This document quantifies some of the effects in SAR which modify the coherence. Although these effects can disrupt the coherence within a single SAR image, this report will focus on the coherence between separate images, such as for coherent change detection (CCD) processing. There have been other presentations on aspects of this material in the past. The intent of this report is to bring various issues that affect the coherence together in a single report to support radar engineers in making decisions about these matters.

  6. PULSED-FOCUSING RECIRCULATING LINACS FOR MUON ACCELERATION

    SciTech Connect (OSTI)

    Johnson, Rolland PAUL

    2014-12-31T23:59:59.000Z

    Since the muon has a short lifetime, fast acceleration is essential for high-energy applications such as muon colliders, Higgs factories, or neutrino factories. The best one can do is to make a linear accelerator with the highest possible accelerating gradient to make the accelerating time as short as possible. However, the cost of such a single linear accelerator is prohibitively large due to expensive power sources, cavities, tunnels, and related infrastructure. As was demonstrated in the Thomas Jefferson Accelerator Facility (Jefferson Lab) Continuous Electron Beam Accelerator Facility (CEBAF), an elegant solution to reduce cost is to use magnetic return arcs to recirculate the beam through the accelerating RF cavities many times, where they gain energy on each pass. In such a Recirculating Linear Accelerator (RLA), the magnetic focusing strength diminishes as the beam energy increases in a conventional linac that has constant strength quadrupoles. After some number of passes the focusing strength is insufficient to keep the beam from going unstable and being lost. In this project, the use of fast pulsed quadrupoles in the linac sections was considered for stronger focusing as a function of time to allow more successive passes of a muon beam in a recirculating linear accelerator. In one simulation, it was shown that the number of passes could be increased from 8 to 12 using pulsed magnet designs that have been developed and tested. This could reduce the cost of linac sections of a muon RLA by 8/12, where more improvement is still possible. The expense of a greater number of passes and corresponding number of return arcs was also addressed in this project by exploring the use of ramped or FFAG-style magnets in the return arcs. A better solution, invented in this project, is to use combined-function dipole-quadrupole magnets to simultaneously transport two beams of different energies through one magnet string to reduce costs of return arcs by almost a factor of two. A patent application was filed for this invention and a detailed report published in Physical Review Special Topics. A scaled model using an electron beam was developed and proposed to test the concept of a dog bone RLA with combined-function return arcs. The efforts supported by this grant were reported in a series of contributions to particle accelerator conferences that are reproduced in the appendices and summarized in the body of this report.

  7. STATUS OF R AND D ENERGY RECOVERY LINAC AT BROOKHAVEN NATIONAL LABORATORY.

    SciTech Connect (OSTI)

    LITVINENKO,V.; BEN-ZVI, I.; ALDUINO, J.M.; BARTON, D.S.; BEAVIS, D.; BLASKIEWICZ, M.; ET AL.

    2007-06-25T23:59:59.000Z

    In this paper we present status and plans for the 20-MeV R&D energy recovery linac (ERL), which is under construction at Collider Accelerator Department at BNL. The facility is based on high current (up to 0.5 A of average current) super-conducting 2.5 MeV RF gun, single-mode super-conducting 5-cell RF linac and about 20-m long return loop with very flexible lattice. The R&D ERL, which is planned for commissioning in early 2009, aims to address many outstanding questions relevant for high current, high brightness energy recovery linacs.

  8. Single Spoke Cavities for Low-energy Part of CW Linac of Project X.

    SciTech Connect (OSTI)

    Gonin, Ivan; Champion, Mark; Khabiboulline, Timergali; Lunin, Andrei; Perunov, Nikolay; Solyak, Nikolay; Yakovlev, Vyacheslav; /Fermilab

    2010-05-01T23:59:59.000Z

    In the low-energy part of the Project X H-linac three families of 325 MHz SC single spoke cavities will be used, having {beta} = 0.11, 0.21 and 0.4. Single spoke cavity was selected for the linac because of higher r/Q. Results of optimization of all cavities are presented. Results of the beam dynamics optimization for initial stage of the linac with beta=0.11 single spoke cavity are presented at poster MOPEC082 (this conference).

  9. Integrating externally developed systems for SNS Linac cooling and vacuum.

    SciTech Connect (OSTI)

    Marroquin, P. S. (Pilar S.)

    2001-01-01T23:59:59.000Z

    External contractors are developing the local cooling and vacuum control systems for the Spallation Neutron Source (SNS) linac. Soon these systems will be integrated into the facility-wide controls system. Allen-Bradley Logix5000 series programmable controllers, populated with appropriate input/output modules, were selected as the local controllers. These controllers will be interfaced to the facility-wide control system via VME systems with PowerPC processors running the Wind River VxWorks operating system and Experimental Physics and Industrial Control System (EPICS) front-end controller software. This paper describes the interface and integration issues driven by project, cooling system and vacuum system requirements and hardware selections.

  10. Wakefield measurements of SLAC linac structures at the Argonne AATF

    SciTech Connect (OSTI)

    Wang, J.W.; Loew, G.A. (Stanford Linear Accelerator Center, Menlo Park, CA (USA)); Simpson, J.; Chojnacki, E.; Gai, W.; Konecny, R.; Schoessow, P. (Argonne National Lab., IL (USA))

    1991-05-01T23:59:59.000Z

    Damped and detuned linac structures designed to minimize the effects of wakefields excited by e{sup {plus minus}} bunch trains in future linear colliders are presently under investigation at SLAC. This paper describes the results of measurements of both longitudinal and transverse wakefields performed at the ANL Advanced Accelerator Test Facility with two SLAC-built X-Band disk-loaded waveguides: a conventional 30-cavity long constant-impedance structure and a non-conventional 50-cavity long structure along which the iris and spacer diameters have been varied so as to stagger-tune the HEM{sub 11} mode frequency by 37%. The results are shown to be in excellent agreement with computations made by KN7C, TRANSVRS, TBCI, and LINACBBU. 8 refs., 5 figs.

  11. Coherent Nuclear Radiation

    E-Print Network [OSTI]

    V. I. Yukalov; E. P. Yukalova

    2004-06-22T23:59:59.000Z

    The main part of this review is devoted to the comprehensive description of coherent radiation by nuclear spins. The theory of nuclear spin superradiance is developed and the experimental observations of this phenomenon are considered. The intriguing problem of how coherence develops from initially incoherent quantum fluctuations is analysed. All main types of coherent radiation by nuclear spins are discussed, which are: free nuclear induction, collective induction, maser generation, pure superradiance, triggered superradiance, pulsing superradiance, punctuated superradiance, and induced emission. The influence of electron-nuclear hyperfine interactions and the role of magnetic anisotropy are studied. Conditions for realizing spin superradiance by magnetic molecules are investigated. The possibility of nuclear matter lasing, accompanied by pion or dibaryon radiation, is briefly touched.

  12. Bidirectional coherent classical communication

    E-Print Network [OSTI]

    Aram W. Harrow; Debbie W. Leung

    2005-05-12T23:59:59.000Z

    A unitary interaction coupling two parties enables quantum communication in both the forward and backward directions. Each communication capacity can be thought of as a tradeoff between the achievable rates of specific types of forward and backward communication. Our first result shows that for any bipartite unitary gate, coherent classical communication is no more difficult than classical communication -- they have the same achievable rate regions. Previously this result was known only for the unidirectional capacities (i.e., the boundaries of the tradeoff). We then relate the tradeoff curve for two-way coherent communication to the tradeoff for two-way quantum communication and the tradeoff for coherent communiation in one direction and quantum communication in the other.

  13. Intense terahertz pulses from SLAC electron beams using coherent transition radiation

    SciTech Connect (OSTI)

    Wu Ziran; Fisher, Alan S.; Hogan, Mark; Loos, Henrik [Accelerator Directorate, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Goodfellow, John [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Fuchs, Matthias [Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Daranciang, Dan [Department of Chemistry, Stanford University, Stanford, California 94305 (United States); Lindenberg, Aaron [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

    2013-02-15T23:59:59.000Z

    SLAC has two electron accelerators, the Linac Coherent Light Source (LCLS) and the Facility for Advanced Accelerator Experimental Tests (FACET), providing high-charge, high-peak-current, femtosecond electron bunches. These characteristics are ideal for generating intense broadband terahertz (THz) pulses via coherent transition radiation. For LCLS and FACET respectively, the THz pulse duration is typically 20 and 80 fs RMS and can be tuned via the electron bunch duration; emission spectra span 3-30 THz and 0.5 THz-5 THz; and the energy in a quasi-half-cycle THz pulse is 0.2 and 0.6 mJ. The peak electric field at a THz focus has reached 4.4 GV/m (0.44 V/A) at LCLS. This paper presents measurements of the terahertz pulses and preliminary observations of nonlinear materials response.

  14. Coherent soliton communication lines

    SciTech Connect (OSTI)

    Yushko, O. V., E-mail: olesya.yushko@gmail.com; Redyuk, A. A.; Fedoruk, M. P.; Turitsyn, S. K. [Novosibirsk State University (Russian Federation)

    2014-11-15T23:59:59.000Z

    The data transmission in coherent fiber-optical communication lines using solitons with a variable phase is studied. It is shown that nonlinear coherent structures (solitons) can be applied for effective signal transmission over a long distance using amplitude and optical-phase keying of information. The optimum ratio of the pulse width to the bit slot at which the spectral efficiency (transmitted bits per second and hertz) is maximal is determined. It is shown that soliton fiber-optical communication lines can ensure data transmission at a higher spectral efficiency as compared to traditional communication lines and at a high signal-to-noise ratio.

  15. Coherence-induced entanglement

    E-Print Network [OSTI]

    Li, F. L.; Xiong, H.; Zubairy, M. Suhail

    2005-01-01T23:59:59.000Z

    . These include correlated spontaneous emission laser #3;2#4;, lasing without in- version #3;3#4;, electromagnetically induced transparence #3;4#4; and spontaneous emission cancellation #3;5#4;. Atomic coherence has recently been shown to play a key role...;9#4;. In this paper we discuss an important application where atomic coherence plays a crucial role in creating entangle- ment between two modes of the electromagnetic field inside a doubly resonant cavity at temperature T, which are coupled to two transitions...

  16. DESIGN/COST STUDY OF AN INDUCTION LINAC FOR HEAVY IONS FOR PELLET-FUSION

    E-Print Network [OSTI]

    Faltens, A.

    2010-01-01T23:59:59.000Z

    LINAC FOR HEAVY IONS FOR PELLET-FUSION* Andris Faltens. EgonContract The physics of the pellet implosion sets strin-deposition in the pellet > 20 MJ/g. Thus, considerable

  17. DESIGN OF THE PROTOTYPICAL CRYOMODULE FOR THE EUROTRANS SUPERCONDUCTING LINAC FOR NUCLEAR WASTE

    E-Print Network [OSTI]

    Boyer, Edmond

    DESIGN OF THE PROTOTYPICAL CRYOMODULE FOR THE EUROTRANS SUPERCONDUCTING LINAC FOR NUCLEAR WASTE of the accelerator workpackage of the EUROTRANS program for the design of a nuclear waste transmutation system

  18. Overview of the High Intensity Neutrino Source Linac R&D program at Fermilab

    SciTech Connect (OSTI)

    Webber, R.C.; Appollinari, G.; Carneiro, J.P.; Gonin, I.; Hanna, B.; Hays, S.; Khabiboulline, T.; Lanfranco, G.; Madrak, R.L.; Moretti, A.; Nicol, T.; /Fermilab /Argonne

    2008-09-01T23:59:59.000Z

    The Fermilab High Intensity Neutrino Source (HINS) Linac R&D program is building a first-of-a-kind 60 MeV superconducting H- linac. The HINS Linac incorporates superconducting solenoids for transverse focusing, high power RF vector modulators for independent control of multiple cavities powered from a single klystron, and superconducting spoke-type accelerating cavities starting at 10 MeV. This will be the first application and demonstration of any of these technologies in a low-energy, high-intensity proton/H- linear accelerator. The HINS effort is relevant to a high intensity, superconducting H- linac that might serve the next generation of neutrino physics and muon storage ring/collider experiments. An overview of the HINS program, machine design, status, and outlook is presented.

  19. Summary of sessions B and F: High intensity linacs and frontend & proton drivers

    SciTech Connect (OSTI)

    Ferdinand, R.; /Saclay; Chou, W.; /Fermilab; Galambos, J.; /Oak Ridge

    2005-01-01T23:59:59.000Z

    This paper summarizes the sessions B&F of the 33rd ICFA Advanced Beam Dynamics Workshop on High Intensity & High Brightness Hadron Beams held in Bensheim, Germany. It covers high intensity linacs, front ends and proton driver topics.

  20. Formation of electron bunches with tailored current profiles using multi-frequency linacs

    SciTech Connect (OSTI)

    Piot, P.; Behrens, C.; Gerth, C.; Lemery, F.; Mihalcea, D.; Stoltz, P. [Northern Illinois Center for Accelerator and Detector Development and Department of Physics, Northern Illinois University, DeKalb, IL 60115 (United States) and Accelerator Physics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85 D-22607 Hamburg (Germany); Northern Illinois Center for Accelerator and Detector Development and Department of Physics, Northern Illinois University, DeKalb, IL 60115 (United States); Tech-X Corporation, Boulder, CO 80303 (United States)

    2012-12-21T23:59:59.000Z

    Tailoring an electron bunch with specific current profile can provide substantial enhancement of the transformer ratio in beam-driven acceleration methods. We present a method relying on the use of a linac with accelerating sections operating at different frequencies followed by a magnetic bunch compressor. The experimental verfification of the technique in a two-frequency linac is presented. The compatibility of the proposed technique with the formation and acceleration of a drive and witness bunches is numerically demonstrated.

  1. Some effects of the transverse-stability requirement on the design of a grating linac

    SciTech Connect (OSTI)

    Kim, K.J.; Kroll, N.M.

    1982-04-01T23:59:59.000Z

    The transverse stability of the grating linac proposed by Palmer is analyzed. It is shown that an open structure such as a grating is always unstable transversely as long as it is uniform. The structure can be made stable by utilizing the strong focusing principle. This is achieved by periodically interrupting the grating shape. We analyze the strong focusing grating linac, and find that the stability requirement places a non-trivial constraint on the phase acceptance of the system.

  2. Radiation Protection Study for the Shielding Design of the LINAC4 Beam Dump at CERN

    E-Print Network [OSTI]

    Blaha, Jan

    2013-01-01T23:59:59.000Z

    The aim of this study is to determine an optimal shielding of the LINAC4 beam dump fulfilling the radiation protection requirements. Therefore a detailed Monte-Carlo calculation using FLUKA particle transport and interaction code has been performed and the relevant physics quantities, such as particle fluences, neutron energy spectra, residual and prompt dose rates, air and water activation have been evaluated for different LINAC4 operation phases.

  3. MEDIUM POWER 352 MHZ SOLID STATE PULSED RF AMPLIFIERS FOR THE CERN LINAC4 PROJECT

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    MEDIUM POWER 352 MHZ SOLID STATE PULSED RF AMPLIFIERS FOR THE CERN LINAC4 PROJECT J. Broere, J in the CERN Linac4. The amplifiers are water-cooled and can provide up to 33 kW pulsed RF Power, 1.5 ms pulse RF Power for the debuncher cavity. The concept is based on 1.2 kW RF power modules using the latest 6

  4. Quantum Coherence Engines

    E-Print Network [OSTI]

    Elias P. Gyftopoulos

    2007-06-20T23:59:59.000Z

    In a report published in Science, Scully et al propose to generate "phaseonium", and "extract work from a single heat bath via vanishing coherence" [1]. On the basis of the laws of physics, such a proposal is futile for at least two reasons.

  5. Coherent hybrid electromagnetic field imaging

    DOE Patents [OSTI]

    Cooke, Bradly J. (Jemez Springs, NM); Guenther, David C. (Los Alamos, NM)

    2008-08-26T23:59:59.000Z

    An apparatus and corresponding method for coherent hybrid electromagnetic field imaging of a target, where an energy source is used to generate a propagating electromagnetic beam, an electromagnetic beam splitting means to split the beam into two or more coherently matched beams of about equal amplitude, and where the spatial and temporal self-coherence between each two or more coherently matched beams is preserved. Two or more differential modulation means are employed to modulate each two or more coherently matched beams with a time-varying polarization, frequency, phase, and amplitude signal. An electromagnetic beam combining means is used to coherently combine said two or more coherently matched beams into a coherent electromagnetic beam. One or more electromagnetic beam controlling means are used for collimating, guiding, or focusing the coherent electromagnetic beam. One or more apertures are used for transmitting and receiving the coherent electromagnetic beam to and from the target. A receiver is used that is capable of square-law detection of the coherent electromagnetic beam. A waveform generator is used that is capable of generation and control of time-varying polarization, frequency, phase, or amplitude modulation waveforms and sequences. A means of synchronizing time varying waveform is used between the energy source and the receiver. Finally, a means of displaying the images created by the interaction of the coherent electromagnetic beam with target is employed.

  6. Maximally coherent mixed states: Complementarity between maximal coherence and mixedness

    E-Print Network [OSTI]

    Uttam Singh; Manabendra Nath Bera; Himadri Shekhar Dhar; Arun Kumar Pati

    2015-03-21T23:59:59.000Z

    Quantum coherence is a key component of topical research on quantum resource theories and a primary facilitator for design and implementation of quantum technologies. However, the resourcefulness of quantum coherence is severely restricted by environmental noise, which is indicated by the loss of information in a quantum system, measured in terms of its purity. In this work, we derive the limits imposed by the mixedness of a quantum system on the amount of quantum coherence that it can possess. We obtain an analytical trade-off between the two quantities that upperbounds the maximum quantum coherence for fixed mixedness in a system. This gives rise to a class of quantum states, "maximally coherent mixed states", whose coherence cannot be increased further under any purity-preserving operation. For the above class of states, quantum coherence and mixedness satisfy a complementarity relation, which is crucial to understand the interplay between a resource and noise in open quantum systems.

  7. Conceptual Design for Replacement of the DTL and CCL with Superconducting RF Cavities in the Spallation Neutron Source Linac

    SciTech Connect (OSTI)

    Champion, Mark S [ORNL] [ORNL; Doleans, Marc [ORNL] [ORNL; Kim, Sang-Ho [ORNL] [ORNL

    2013-01-01T23:59:59.000Z

    The Spallation Neutron Source Linac utilizes normal conducting RF cavities in the low energy section from 2.5 MeV to 186 MeV. Six Drift Tube Linac (DTL) structures accelerate the beam to 87 MeV, and four Coupled Cavity Linac (CCL) structures provide further acceleration to 186 MeV. The remainder of the Linac is comprised of 81 superconducting cavities packaged in 23 cryomodules to provide final beam energy of approximately 1 GeV. The superconducting Linac has proven to be substantially more reliable than the normal conducting Linac despite the greater number of stations and the complexity associated with the cryogenic plant and distribution. A conceptual design has been initiated on a replacement of the DTL and CCL with superconducting RF cavities. The motivation, constraints, and conceptual design are presented.

  8. Attempted RIAPMTQ Benchmarking Study of the ANL RIA Low-Beta LinacDesign

    SciTech Connect (OSTI)

    Billen, J.; Qiang, J.; Wangler, T.

    2007-01-01T23:59:59.000Z

    The objective of this work is to compare the simulation results of the RIAPMTQ code with those of the ANL simulation code for the low-beta section of an ANL RIA Driver Linac design. However, the approach taken is not precisely that of a direct comparison of the two simulations of the same linac section, which is what one would normally expect to do. The reason is that the RFQ design approach used by the ANL codes and the LANL codes are approximately but not exactly the same, particularly at the ends of the RFQ, and it did not appear to be easy to make the two RFQ designs exactly identical. The effects on the beam of the different RFQ design approaches are not expected to be large, as long as the beam is properly matched at the transitions. What was done in the RIAPMTQ input file to compensate for the RFQ design difference was to use TRACE3D to adjust the four solenoid strengths and the two matching rf cavities in the MEBT (the beam transport system between the end of the RFQ and the beginning of the superconducting linac) to obtain the same match (Courant-Snyder parameters) into the superconducting linac as was obtained from the ANL code. We also matched the beam into the RFQ. The result is that we generate a RIAPMTQ input file for the low-beta section of the linac, which is not exactly identical to, but should be near to that of the ANL design. Then, what we wish to compare from the two codes are the rms emittances at the beginning of the superconducting linac, and the beam losses in the first or prestripper section of the superconducting (SC) linac. In this report, we describe the procedure and present the results. Section 2 gives the procedures and results, and Section 3 gives the summary.

  9. LANSCE Drift Tube Linac Water Control System Refurbishment

    SciTech Connect (OSTI)

    Marroquin, Pilar S. [Los Alamos National Laboratory

    2011-01-01T23:59:59.000Z

    There are several refurbishment projects underway at the Los Alamos National Laboratory LANSCE linear accelerator. Systems involved are: RF, water cooling, networks, diagnostics, timing, controls, etc. The Drift Tube Linac (DTL) portion of the accelerator consists of four DTL tanks, each with three independent water control systems. The systems are about 40 years old, use outdated and non-replaceable equipment and NIM bin control modules, are beyond their design life and provide unstable temperature control. Insufficient instrumentation and documentation further complicate efforts at maintaining system performance. Detailed design of the replacement cooling systems is currently in progress. Previous design experience on the SNS accelerator water cooling systems will be leveraged, see the SNS DTL FDR. Plans call for replacement of water piping, manifolds, pumps, valves, mix tanks, instrumentation (flow, pressure and temperature) and control system hardware and software. This presentation will focus on the control system design with specific attention on planned use of the National Instruments Compact RIO platform with the Experimental Physics and Industrial Control system (EPICS) software toolkit.

  10. Field stability in two-stem drift-tube linacs

    SciTech Connect (OSTI)

    Billen, J.H.; Spalek, G.; Shapiro, A.H.

    1988-01-01T23:59:59.000Z

    Drift tubes supported by two stems have been considered for cryogenic drift-tube linacs (DTLs) to reduce vibrations and to minimize drift-tube deflections upon cool down. We investigated rf properties of two-stem DTL structures at room temperature and low power. Even apart is inherently more stable against tuning errors than a similar structure with single stems. The increased stability is higher for DTLs with shorter drift tubes. Ordinary quarter-wavelength-long post couplers actually destabilize the two-stem DTL fields; the extra stem raises the post coupler frequency compared to the frequency of the same post coupler extended beyond the tank wall into coaxial stub tuners. Adjustment of the stub lengths tunes the post-coupler frequencies, but post-coupler lengths in the tank have no effect, which suggests a field pattern different from traditional post couplers. The stabilized DTL resembles multiple-stem DTLs in which the angle between stems is varied to achieve stabilization. Adjusting the coaxial stub length is mechanically simpler than changing the stem azimuth angle. 5 refs., 6 figs., 1 tab.

  11. Higher Order Mode Heating Analysis for the ILC Superconducting Linacs

    SciTech Connect (OSTI)

    Bane, K.L.F.; Nantista, C.; Adolphsen, C.; /SLAC; ,

    2010-10-27T23:59:59.000Z

    The superconducting cavities and interconnects in the 11 km long linacs of the International Linear Collider (ILC) are designed to operate at 2K, where cooling costs are very expensive. It is thus important to minimize cryogenic heat loads. In addition to an unavoidable static load and the dynamic load of the fundamental 1.3 GHz accelerating rf, a further heat source is presented by the higher order mode (HOM) power deposited by the beam. Such modes will be damped by specially designed HOM couplers attached to the cavities (for trapped modes), and by ceramic dampers at 70K that are located between the eight or nine cavity cryomodules (for propagating modes). Brute force calculation of the higher frequency modes excited in a string of cryomodules is limited by computing capacity (see, e.g. [1]). M. Liepe has calculated {approx} 400 longitudinal TM modes in 3 superconducting cavities plus absorbers, up to 8 GHz [2]. Joestingmeier, et al., have used a ray tracing calculation to find the effect at higher frequencies, specifically in the range of tens of GHz and above [3]. In this report we present a scattering matrix approach, which we apply to an rf unit comprising 26 cavities and 3 absorbers. We perform calculations at sample frequencies (up to 20 GHz) to predict the effectiveness of the ceramic dampers in limiting HOM heat deposition at 2K.

  12. Progress update on cryogenic system for ARIEL E-linac at TRIUMF

    SciTech Connect (OSTI)

    Koveshnikov, A.; Bylinskii, I.; Hodgson, G.; Yosifov, D. [TRIUMF, Vancouver, BC, V6T 2A3 (Canada)

    2014-01-29T23:59:59.000Z

    TRIUMF is involved in a major upgrade. The Advanced Rare IsotopeE Laboratory (ARIEL) has become a fully funded project in July 2010. A 10 mA 50 MeV SRF electron linac (e-linac) operating CW at 1.3 GHz is the key component of this initiative. This machine will serve as a second independent photo-fission driver for Rare Isotope Beams (RIB) production at TRIUMF's Isotope Separator and Accelerator (ISAC) facility. The cryogens delivery system requirements are driven by the electron accelerator cryomodule design [1, 2]. Since commencement of the project in 2010 the cryogenic system of e-linac has moved from the conceptual design phase into engineering design and procurement stage. The present document summarizes the progress in cryogenic system development and construction. Current status of e-linac cryogenic system including details of LN{sub 2} storage and delivery systems, and helium subatmospheric (SA) system is presented. The first phase of e-linac consisting of two cryomodules, cryogens storage, delivery, and distribution systems, and a 600 W class liquid helium cryoplant is scheduled for installation and commissioning by year 2014.

  13. Measurements of the LCLS Laser Heater and its impact on the x-ray FEL Performance

    SciTech Connect (OSTI)

    Huang, Zhirong; Brachmann, A.; Decker, F.-J.; Ding, Y.; Dowell, D.; Emma, P.; Frisch, J.; Gilevich, S.; Hays, G.; Hering, Ph.; Iverson, R.; Loos, H.; Miahnahri, A.; Nuhn, H.-D.; Ratner, D.; Stupakov, G.; Turner, J.; Welch, J.; White, W.; Wu, J.; Xiang, D.

    2009-12-17T23:59:59.000Z

    The very bright electron beam required for an x-ray free-electron laser (FEL), such as the Linac Coherent Light Source (LCLS), is susceptible to a microbunching instability in the magnetic bunch compressors, prior to the FEL undulator. The uncorrelated electron energy spread in the LCLS can be increased by an order of magnitude to provide strong Landau damping against the instability without degrading the FEL performance. To this end, a 'laser-heater' system has been installed in the LCLS injector, which modulates the energy of a 135-MeV electron bunch with an IR laser beam in a short undulator, enclosed within a four-dipole chicane. In this paper, we report detailed measurements of laser heater-induced energy spread, including the unexpected self-heating phenomenon when the laser energy is very low. We discuss the suppression of the microbunching instability with the laser heater and its impact on the x-ray FEL performance. We also present the analysis of these experimental results and develop a three-dimensional longitudinal space charge model to explain the self-heating effect.

  14. Stanford University Faculty Positions in Science related to use of the Linac Coherent Light Source (LCLS) at the

    E-Print Network [OSTI]

    Wechsler, Risa H.

    (LCLS) at the SLAC National Accelerator Laboratory We invite applications for faculty positions Light Source (LCLS). Applicants should at minimum hold an earned doctorate in a core science-ray capabilities of the LCLS. For example, this unique experimental facility provides new opportunities

  15. 7 Å Resolution in Protein 2-Dimentional-Crystal X-Ray Diffraction at Linac Coherent Light Source

    SciTech Connect (OSTI)

    Pedrini, Bill; Tsai, Ching-Ju; Capitani, Guido; Padeste, Celestino; Hunter, Mark; Zatsepin, Nadia A.; Barty, Anton; Benner, Henry; Boutet, Sebastien; Feld, Geoffrey K.; Hau-Riege, Stefan; Kirian, Rick; Kupitz, Christopher; Messerschmidt, Marc; Ogren, John I.; Pardini, Tommaso; Segelke, Brent; Williams, Garth J.; Spence , John C.; Abela, Rafael; Coleman, Matthew A.; Evans, James E.; Schertler, Gebhard; Frank, Matthias; Li, Xiao-Dan

    2014-06-09T23:59:59.000Z

    Membrane proteins arranged as two-dimensional (2D) crystals in the lipid en- vironment provide close-to-physiological structural information, which is essential for understanding the molecular mechanisms of protein function. X-ray diffraction from individual 2D crystals did not represent a suitable investigation tool because of radiation damage. The recent availability of ultrashort pulses from X-ray Free Electron Lasers (X-FELs) has now provided a mean to outrun the damage. Here we report on measurements performed at the LCLS X-FEL on bacteriorhodopsin 2D crystals mounted on a solid support and kept at room temperature. By merg- ing data from about a dozen of single crystal diffraction images, we unambiguously identified the diffraction peaks to a resolution of 7 °A, thus improving the observable resolution with respect to that achievable from a single pattern alone. This indicates that a larger dataset will allow for reliable quantification of peak intensities, and in turn a corresponding increase of resolution. The presented results pave the way to further X-FEL studies on 2D crystals, which may include pump-probe experiments at subpicosecond time resolution.

  16. Coherent states on the circle

    E-Print Network [OSTI]

    Chadzitaskos, G; Tolar, J

    2011-01-01T23:59:59.000Z

    We present a possible construction of coherent states on the unit circle as configuration space. In our approach the phase space is the product Z x S^1. Because of the duality of canonical coordinates and momenta, i.e. the angular variable and the integers, this formulation can also be interpreted as coherent states over an infinite periodic chain. For the construction we use the analogy with our quantization over a finite periodic chain where the phase space was Z_M x Z_M. Properties of the coherent states constructed in this way are studied and the coherent states are shown to satisfy the resolution of unity.

  17. Resonance Excitation of Longitudinal High Order Modes in Project X Linac

    SciTech Connect (OSTI)

    Khabiboulline, T.N.; Sukhanov, A.AUTHOR = Awida, M.; Gonin, I.; Lunin, A.AUTHOR = Solyak, N.; Yakovlev, V.; /Fermilab

    2012-05-01T23:59:59.000Z

    Results of simulation of power loss due to excitation of longitudinal high order modes (HOMs) in the accelerating superconducting RF system of CW linac of Project X are presented. Beam structures corresponding to the various modes of Project X operation are considered: CW regime for 3 GeV physics program; pulsed mode for neutrino experiments; and pulsed regime, when Project X linac operates as a driver for Neutrino Factory/Muon Collider. Power loss and associated heat load due to resonance excitation of longitudinal HOMs are shown to be small in all modes of operation. Conclusion is made that HOM couplers can be removed from the design of superconducting RF cavities of Project X linac.

  18. Analysis of the microbunching instability in a mid-energy electron linac

    E-Print Network [OSTI]

    Huang, Dazhang; Wang, Zhen; Zhang, Meng; Ng, King Yuen

    2014-01-01T23:59:59.000Z

    Microbunching instability usually exists in the linear accelerator (linac) of a free electron laser (FEL) facility. If it is not controlled effectively, the beam quality will be damaged seriously and the machine will not operate properly. In the electron linac of a soft X-Ray FEL device, because the electron energy is not very high, the problem can become even more serious. As a typical example, the microbunching instability in the linac of the proposed Shanghai Soft X-ray Free Electron Laser facility (SXFEL) is investigated in detail by means of both analytical formulae and simulation tools. In the study, a new mechanism of introducing random noise into the beam current profile as the beam passes through a chicane-type bunch compressor is proposed. The higher-order modes that appear in the simulations suggest that further improvement of the current theoretical model of the instability is needed.

  19. An electron front end for the Fermilab multi-species 8 GeV SCRF linac

    SciTech Connect (OSTI)

    Philippe R.-G. Piot; G W Foster

    2004-07-08T23:59:59.000Z

    Fermilab is considering a 8 GeV superconducting linac whose primary mission is to serve as an intense H{sup -} injector for the main injector. This accelerator is also planned to be used for accelerating various other species (e.g. electrons, protons and muons). In the present paper we investigate the possibility of such a linac to accelerate high-brightness electron beam up to {approx} 7 GeV. We propose a design for the electron front end based on a photoinjector and consider the electron beam dynamics along the linac. Start-to-end simulations of the full accelerator for electrons are presented. Finally the potential applications of such an electron beam are outlined.

  20. Commissioning of the CERN LINAC4 BPM System with 50 Mev Proton Beamns

    E-Print Network [OSTI]

    Tan, J; Søby, L; Sordet, M; Wendt, M

    2013-01-01T23:59:59.000Z

    The new Linac4 at CERN will provide a 160 MeV H- ion beam for charge-exchange injection into the existing CERN accelerator complex. Shorted stripline pick-ups placed in the Linac intertank regions and the transfer lines will measure beam orbit, relative beam current, beam phase, and average beam energy via the time-of-flight between two pickups. A prototype Beam Position Monitor (BPM) system has been installed in the transfer line between the existing Linac2 and the Proton Synchrotron Booster (PSB) in order to study and review the complete acquisition chain. This paper presents measurements and performance of this BPM system operating with 50 MeV proton beams, and compares the results with laboratory measurements and electromagnetic simulations.

  1. Transverse Beam Emittance Measurements of a 16 MeV Linac at the Idaho Accelerator Center

    SciTech Connect (OSTI)

    S. Setiniyaz, T.A. Forest, K. Chouffani, Y. Kim, A. Freyberger

    2012-07-01T23:59:59.000Z

    A beam emittance measurement of the 16 MeV S-band High Repetition Rate Linac (HRRL) was performed at Idaho State University's Idaho Accelerator Center (IAC). The HRRL linac structure was upgraded beyond the capabilities of a typical medical linac so it can achieve a repetition rate of 1 kHz. Measurements of the HRRL transverse beam emittance are underway that will be used to optimize the production of positrons using HRRL's intense electron beam on a tungsten converter. In this paper, we describe a beam imaging system using on an OTR screen and a digital CCD camera, a MATLAB tool to extract beamsize and emittance, detailed measurement procedures, and the measured transverse emittances for an arbitrary beam energy of 15 MeV.

  2. PHOTOINJECTED ENERGY RECOVERY LINAC UPGRADE FOR THE NATIONAL SYNCHROTRON LIGHT SOURCE.

    SciTech Connect (OSTI)

    BEN-ZVI,I.; BABZIEN,M.; BLUM,E.; CASEY,W.; CHANG,X.; GRAVES,W.; HASTINGS,J.; HULBERT,S.; JOHNSON,E.; KAO,C.C.; KRAMER,S.; KRINSKY,S.; MORTAZAVI,P.; MURPHY,J.; OZAKI,S.; PJEROV,S.; PODOBEDOV,B.; RAKOWSKY,G.; ROSE,J.; SHAFTAN,T.; SHEEHY,B.; SIDDONS,D.; SMEDLEY,J.; SRINIVASAN-RAO,T.; TOWNE,N.; WANG,J.M.; WANG,X.; WU,J.; YAKIMENKO,V.; YU,L.H.

    2001-06-18T23:59:59.000Z

    We describe a major paradigm shift in the approach to the production of synchrotron radiation This change will considerably improve the scientific capabilities of synchrotron light sources. We introduce plans for an upgrade of the National Synchrotron Light Source (NSLS). This upgrade will be based on the Photoinjected Energy Recovering Linac (PERL). This machine emerges from the union of two technologies, the laser-photocathode RF gun (photoinjector) and superconducting linear accelerators with beam energy recovery (Energy Recovering Linac). The upgrade will bring the NSLS users many new insertion device beam lines, brightness greater than 3rd generation lightsource's and ultra-short pulse capabilities, not possible with storage ring light sources.

  3. Space Charge Compensation in the Linac4 Low Energy Beam Transport Line with Negative Hydrogen Ions

    E-Print Network [OSTI]

    Valerio-Lizarraga, C; Leon-Monzon, I; Lettry, J; Midttun, O; Scrivens, R

    2013-01-01T23:59:59.000Z

    The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Tranport (LEBT) using the package IBSimu1, which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H- beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

  4. INCREASED UNDERSTANDING OF BEAM LOSSES FROM THE SNS LINAC PROTON EXPERIMENT

    SciTech Connect (OSTI)

    Aleksandrov, Alexander V [ORNL] [ORNL; Shishlo, Andrei P [ORNL] [ORNL; Plum, Michael A [ORNL] [ORNL; Lebedev, Valerie [FNAL] [FNAL; Laface, Emanuele [ESS] [ESS; Galambos, John D [ORNL] [ORNL

    2013-01-01T23:59:59.000Z

    Beam loss is a major concern for high power hadron accelerators such as the Spallation Neutron Source (SNS). An unexpected beam loss in the SNS superconducting linac (SCL) was observed during the power ramp up and early operation. Intra-beam-stripping (IBS) loss, in which interactions between H- particles within the accelerated bunch strip the outermost electron, was recently identified as a possible cause of the beam loss. A set of experiments using proton beam acceleration in the SNS linac was conducted, which supports IBS as the primary beam loss mechanism in the SNS SCL.

  5. Engineering development of superconducting RF linac for high-power applications

    SciTech Connect (OSTI)

    Dominic Chan, K.C.; Rusnak, B.; Gentzlinger, R.C.; Campbell, B.M.; Kelley, J.P. [Los Alamos National Lab., NM (United States); Safa, H. [CEA Saclay (France)

    1998-12-31T23:59:59.000Z

    High-power proton linacs are a promising source of neutrons for material processing and research applications. Superconducting radiofrequency (SCRF) Rf linac technology is preferred for such applications because of power efficiency. A multi-year engineering development program is underway at Los Alamos National Laboratory to demonstrate the required SCRF technology. The program consists of development of SC cavities, power couplers, and cryomodule integration. Prototypes will be built and operated to obtain performance and integration information, and for design improvement. This paper describes the scope and present status of the development program.

  6. Polaron Coherence Condensation in Layered Colossal Resistive...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    are a generic controlling factor for novel quantum phenomena in doped transition-metal oxides. Coherence Rules the Day When physicists speak of coherence, they are...

  7. Large-acceptance linac for accelerating l9w-energy muons

    SciTech Connect (OSTI)

    Kurennoy, Sergey S [Los Alamos National Laboratory; Jason, Andrew J [Los Alamos National Laboratory; Miyadera, Haruo [Los Alamos National Laboratory

    2010-01-01T23:59:59.000Z

    We propose a high-gradient linear accelerator for accelerating low-energy muons and pions in a strong solenoidal magnetic field. The acceleration starts immediately after collection of pions from a target by solenoidal magnets and brings muons to a kinetic energy of about 200 MeV over a distance of the order of 10 m. At this energy, both an ionization cooling of the muon beam and its further acceleration in a superconducting linac become feasible. The project presents unique challenges - a very large energy spread in a highly divergent beam, as well as pion and muon decays - requiring large longitudinal and transverse acceptances. One potential solution incorporates a normal-conducting linac consisting of independently fed O-mode RF cavities with wide apertures closed by thin metal windows or grids. The guiding magnetic field is provided by external superconducting solenoids. The cavity choice, overall linac design considerations, and simulation results of muon acceleration are presented. While the primary applications of such a linac are for homeland defense and industry, it can provide muon fluxes high enough to be of interest for physics experiments.

  8. ECOS-LINCE: A HIGH INTENSITY MULTI-ION SUPERCONDUCTING LINAC FOR NUCLEAR STRUCTURE AND REACTIONS

    E-Print Network [OSTI]

    Boyer, Edmond

    ECOS-LINCE: A HIGH INTENSITY MULTI-ION SUPERCONDUCTING LINAC FOR NUCLEAR STRUCTURE AND REACTIONS I as part of the Long-Range Plan of the Nuclear-Physics community. LINCE will be a multi-user facility dedicated to ECOS science: fundamental physics, astrophysics, nuclear structure and reaction dynamics

  9. On-Line Measurement and Tuning of Multi-Pass Recirculation Time in the CEBAF Linacs

    E-Print Network [OSTI]

    On-Line Measurement and Tuning of Multi-Pass Recirculation Time in the CEBAF Linacs Michael, USA Abstract CEBAF is a CW, recirculating electron accelerator, us- ing on-crest RF acceleration the beam to drift off-crest with respect to the accelerating fields. Figure 1: Layout of CEBAF Accelerator

  10. A NEW HIGH ENERGY RESOLUTION NEUTRON TRANSMISSION DETECTOR SYSTEM AT THE GAERTTNER LINAC LABORATORY

    E-Print Network [OSTI]

    Danon, Yaron

    Laboratory P.O. Box 1072, Schenectady, New York 12301-1072 A new high energy resolution modular neutronA NEW HIGH ENERGY RESOLUTION NEUTRON TRANSMISSION DETECTOR SYSTEM AT THE GAERTTNER LINAC LABORATORY capabilities at the Laboratory in and above the resolved resonance energy region from 1 keV to 600 ke

  11. DEVELOPMENT OF NIOBIUM SPOKE CAVITIES FOR A SUPERCONDUCTING LIGHT-ION LINAC

    E-Print Network [OSTI]

    DEVELOPMENT OF NIOBIUM SPOKE CAVITIES FOR A SUPERCONDUCTING LIGHT-ION LINAC K. W. Shepard and M the development of 350 MHz niobium superconducting cavities for the velocity range 0.2 geometries are presented. The design and construction status of prototype niobium cavities is discussed. 1

  12. R & D on Very-High-Current Superconducting Proton Linac, Final Report

    SciTech Connect (OSTI)

    Ben-Zvi, Ilan

    2013-03-31T23:59:59.000Z

    The aim of this R&D project was to develop a superconducting cavity for a very-­? high-­?current proton accelerator. The particular application motivating the proposal was a LHC upgrade called the Superconducting Proton Linac, or SPL. Under the grant awarded to Stony Brook University the cavity was designed, a prototype copper cavity, followed by the niobium cavity, were built. A new set of HOM dampers was developed. The cavity has outstanding RF performance parameters – low surface fields, low power loss and all HOMs are fully damped. In fact, it is a “universal cavity” in the sense that it is suited for the acceleration of high-­?current protons and well as high current electrons. Its damping of HOM modes is so good that it can see service in a multi-­?pass linac or an Energy Recovery Linac in addition to the easier service in a single-­?pass linac. Extensive measurements were made on the cavities and couplers, with the exception of the cold test of the niobium cavity. At the time of this report the cavity has been chemically processed and is ready for vertical testing which will be carried out shortly.

  13. Novel linac structures for low-beta ions and for muons

    SciTech Connect (OSTI)

    Kurennoy, Sergey S [Los Alamos National Laboratory

    2010-01-01T23:59:59.000Z

    Development of two innovative linacs is discussed. (1) High-efficiency normal-conducting accelerating structures for ions with beam velocities in the range of a few percent of the speed of light. Two existing accelerator technologies - the H-mode resonator cavities and transverse beam focusing by permanent-magnet quadrupoles (PMQ) - are merged to create efficient structures for light-ion beams of considerable currents. The inter-digital H-mode accelerator with PMQ focusing (IH-PMQ) has the shunt impedance 10-20 times higher than the standard drift-tube linac. Results of the combined 3-D modeling for an IH-PMQ accelerator tank - electromagnetic computations, beam-dynamics simulations, and thermal-stress analysis - are presented. H-PMQ structures following a short RFQ accelerator can be used in the front end of ion linacs or in stand-alone applications like a compact mobile deuteron-beam accelerator up to a few MeV. (2) A large-acceptance high-gradient linac for accelerating low-energy muons in a strong solenoidal magnetic field. When a proton beam hits a target, many low-energy pions are produced almost isotropically, in addition to a small number of high-energy pions in the forward direction. We propose to collect and accelerate copious muons created as the low-energy pions decay. The acceleration should bring muons to a kinetic energy of {approx}200 MeV in about 10 m, where both an ionization cooling of the muon beam and its further acceleration in a superconducting linac become feasible. One potential solution is a normal-conducting linac consisting of independently fed O-mode RF cavities with wide apertures closed by thin metal windows or grids. The guiding magnetic field is provided by external superconducting solenoids. The cavity choice, overall linac design considerations, and simulation results of muon acceleration are presented. Potential applications range from basic research to homeland defense to industry and medicine.

  14. Electron Bunch Profile Reconstruction in the Few fs Regime using Coherent Smith-Purcell Radiation

    SciTech Connect (OSTI)

    Bartolini, R.; /Oxford U., JAI /Diamond Light Source /SLAC; Clarke, C.; /SLAC; Delerue, N; /Oxford U., JAI /Diamond Light Source /SLAC; Doucas, G; Reichold, A; /Oxford U., JAI

    2012-06-20T23:59:59.000Z

    Advanced accelerators for fourth generation light sources based on high brightness linacs or laser-driven wakefield accelerators will operate with intense, highly relativistic electron bunches that are only a few fs long. Diagnostic techniques for the determination of temporal profile of such bunches are required to be non invasive, single shot, economic and with the required resolution in the fs regime. The use of a radiative process such as coherent Smith-Purcell radiation (SPR), is particularly promising with this respect. In this technique the beam is made to radiate a small amount of electromagnetic radiation and the temporal profile is reconstructed from the measured spectral distribution of the radiation. We summarise the advantages of SPR and present the design parameters and preliminary results of the experiments at the FACET facility at SLAC. We also discuss a new approach to the problem of the recovery of the 'missing phase', which is essential for the accurate reconstruction of the temporal bunch profile.

  15. Coherent control of plasma dynamics

    E-Print Network [OSTI]

    He, Z -H; Lebailly, V; Nees, J A; Krushelnick, K; Thomas, A G R

    2015-01-01T23:59:59.000Z

    Coherent control of a system involves steering an interaction to a final coherent state by controlling the phase of an applied field. Plasmas support coherent wave structures that can be generated by intense laser fields. Here, we demonstrate the coherent control of plasma dynamics in a laser wakefield electron acceleration experiment. A genetic algorithm is implemented using a deformable mirror with the electron beam signal as feedback, which allows a heuristic search for the optimal wavefront under laser-plasma conditions that is not known a priori. We are able to improve both the electron beam charge and angular distribution by an order of magnitude. These improvements do not simply correlate with having the `best' focal spot, since the highest quality vacuum focal spot produces a greatly inferior electron beam, but instead correspond to the particular laser phase that steers the plasma wave to a final state with optimal accelerating fields.

  16. Coherent control of neutron interferometry

    E-Print Network [OSTI]

    Pushin, Dmitry A

    2007-01-01T23:59:59.000Z

    In this thesis, several novel techniques are proposed and demonstrated for measuring the coherent properties of materials and testing aspects of quantum information processing using a single crystal neutron interferometer. ...

  17. Highly Efficient Coherent Raman Generation

    E-Print Network [OSTI]

    Hua, Xia

    2014-08-04T23:59:59.000Z

    , and to my daughter Christina Tzu-Hsin Hua for the happiness she brings to me. vii NOMENCLATURE SpRS spontaneous Raman scattering SRS stimulated Raman scattering CARS coherent anti-Stokes Raman scattering CSRS coherent Stokes Raman scattering... wavelength at 672 nm. ................................................................................... 75 Figure 41 The electric field spectral amplitudes of the incident pump (green), Stokes (orange), and probe (red) laser pulses with normalized...

  18. Quantum coherence and correlations in quantum system

    E-Print Network [OSTI]

    Zhengjun Xi; Yongming Li; Heng Fan

    2014-12-24T23:59:59.000Z

    Criteria of measure quantifying quantum coherence, a unique property of quantum system, are proposed recently. In this paper, we firstly give an uncertainty-like expression relating the coherence and the entropy of quantum system. Then, we obtain three trade-offs among the coherence, the discord and the deficit in the bipartite quantum system.As a consequence, we obtain that the relative entropy of coherence satisfies the super-additivity. Finally, we discuss the relations between the entanglement and the coherence.

  19. EA-1904: Finding of No Significant Impact | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy China U.S.ContaminationJuly 2011DDelphi AutomotiveLinac Coherent Light Source-IILinac

  20. EA-1905: Finding of No Significant Impact | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy China U.S.ContaminationJuly 2011DDelphi AutomotiveLinac Coherent LightThe DOE CBFO

  1. EA-1906: Finding of No Significant Impact | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy China U.S.ContaminationJuly 2011DDelphi AutomotiveLinac Coherent LightThe DOE

  2. EA-1907: Finding of No Significant Impact | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy China U.S.ContaminationJuly 2011DDelphi AutomotiveLinac Coherent LightThe

  3. EA-1909: Finding of No Significant Impact | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy China U.S.ContaminationJuly 2011DDelphi AutomotiveLinac Coherent LightTheProject,Based on

  4. EA-1912: Finding of No Significant Impact | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy China U.S.ContaminationJuly 2011DDelphi AutomotiveLinac Coherent

  5. EA-1913: Finding of No Significant Impact | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy China U.S.ContaminationJuly 2011DDelphi AutomotiveLinac CoherentBenton County, WA

  6. EA-1914: Finding of No Significant Impact | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy China U.S.ContaminationJuly 2011DDelphi AutomotiveLinac CoherentBentonNational

  7. Atmospheric rivers as Lagrangian coherent structures

    E-Print Network [OSTI]

    Garaboa, Daniel; Huhn, Florian; Perez-Muñuzuri, Vicente

    2015-01-01T23:59:59.000Z

    We show that filamentous Atmospheric Rivers (ARs) over the Northern Atlantic Ocean are closely linked to attracting Lagrangian Coherent Structures (LCSs) in the large scale wind field. LCSs represent lines of attraction in the evolving flow with a significant impact on all passive tracers. Using Finite-Time Lyapunov Exponents (FTLE), we extract LCSs from a two-dimensional flow derived from water vapor flux of atmospheric reanalysis data and compare them to the three-dimensional LCS obtained from the wind flow. We correlate the typical filamentous water vapor patterns of ARs with LCSs and find that LCSs bound the filaments on the back side. Passive advective transport of water vapor from tropical latitudes is potentially possible.

  8. Optimal focusing for a linac-based hard x-ray source

    SciTech Connect (OSTI)

    Liu, C.; Krafft, G.; Talman, R.

    2011-03-28T23:59:59.000Z

    In spite of having a small average beam current limit, a linac can have features that make it attractive as an x-ray source: high energy, ultralow emittance and energy spread, and flexible beamline optics. Unlike a storage ring, in which an (undulator) radiation source is necessarily short and positioned at an electron beam waist, in a linac the undulator can be long and the electron beam can be adjusted to have a (virtual) waist far downstream toward the x-ray target. Using a planned CEBAF beamline as an example, this paper shows that a factor of 2000 in beam current can be overcome to produce a monochromatic hard x-ray source comparable with, or even exceeding, the performance of an x-ray line at a third generation storage ring. Optimal electron beam focusing conditions for x-ray flux density and brilliance are derived, and are verified by simulations using the SRW code.

  9. Induction linac-driven free-electron lasers: Status and future prospects

    SciTech Connect (OSTI)

    Prosnitz, D.

    1987-01-11T23:59:59.000Z

    The high repetition rate and low single-pass gain inherent in an rf-driven Free Electron Laser (FEL) dictate that the laser system be configured as an oscillator. This allows the laser's electric field to build up over many passes around a high Q cavity. By way of contrast, the high-current capability of the Induction Linac (IL) system permits high single-pass optical gain, but the relatively low duty factor precludes oscillator operation; the pulses are neither long enough nor often enough to permit a field to accumulate in a cavity. The IL is thus configured as a MOPA (master oscillator/power amplifier) with a conventional laser serving as the MO. This report concentrates on the status of IL-driven FEL research at LLNL and gives a description of several applications for the high-peak-power radiation produced by an induction linac FEL.

  10. Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions

    SciTech Connect (OSTI)

    Valerio-Lizarraga, Cristhian A., E-mail: cristhian.alfonso.valerio.lizarraga@cern.ch [CERN, Geneva (Switzerland); Departamento de Investigación en Física, Universidad de Sonora, Hermosillo (Mexico); Lallement, Jean-Baptiste; Lettry, Jacques; Scrivens, Richard [CERN, Geneva (Switzerland)] [CERN, Geneva (Switzerland); Leon-Monzon, Ildefonso [Facultad de Ciencias Fisico-Matematicas, Universidad Autónoma de Sinaloa, Culiacan (Mexico)] [Facultad de Ciencias Fisico-Matematicas, Universidad Autónoma de Sinaloa, Culiacan (Mexico); Midttun, Øystein [CERN, Geneva (Switzerland) [CERN, Geneva (Switzerland); University of Oslo, Oslo (Norway)

    2014-02-15T23:59:59.000Z

    The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Transport using the package IBSimu [T. Kalvas et al., Rev. Sci. Instrum. 81, 02B703 (2010)], which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H{sup ?} beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

  11. Error and jitter effect studies on the SLED for BEPCII-linac

    E-Print Network [OSTI]

    Shi-Lun, Pei; Ou-Zheng, Xiao

    2011-01-01T23:59:59.000Z

    RF pulse compressor is a device to convert a long RF pulse to a short one with much higher peak RF magnitude. SLED can be regarded as the earliest RF pulse compressor used in large scale linear accelerators. It is widely studied around the world and applied in the BEPC and BEPCII linac for many years. During the routine operation, the error and jitter effects will deteriorate the SLED performance either on the output electromagnetic wave amplitude or phase. The error effects mainly include the frequency drift induced by cooling water temperature variation and the frequency/Q0/{\\beta} unbalances between the two energy storage cavities caused by mechanical fabrication or microwave tuning. The jitter effects refer to the PSK switching phase and time jitters. In this paper, we re-derived the generalized formulae for the conventional SLED used in the BEPCII linac. At last, the error and jitter effects on the SLED performance are investigated.

  12. A Dynamic Feedback Model for High Repetition Rate LINAC-Driven FELS

    SciTech Connect (OSTI)

    Mellado Munoz, M.; Doolittle, L.; Emma, P.; Huang, G.; Ratti, A.; Serrano, C.; Byrd, J. M.

    2012-05-20T23:59:59.000Z

    One of the concepts for the next generation of linacdriven FELs is a CW superconducting linac driving an electron beam with MHz repetition rates. One of the challenges for next generation FELs is improve the stability of the xray pulses by improving the shot-to-shot stability of the energy, charge, peak current, and timing jitter of the electron beam. A high repetition rate FEL with a CW linac presents an opportunity to use a variety of broadband feedbacks to stabilize the beam parameters. To understand the performance of such a feedback system, we are developing a dynamic model of the machine with a focus on the longitudinal beam properties. The model is being developed as an extension of the LITrack code and includes the dynamics of the beam-cavity interaction, RF feedback, beam-based feedback, and multibunch effects. In this paper, we present a detailed description of this model.

  13. Emittance Reduction between EBIS LINAC and Booster by Electron Beam Cooling; Is Single Pass Cooling Possible?

    SciTech Connect (OSTI)

    Hershcovitch,A.

    2008-04-01T23:59:59.000Z

    Electron beam cooling is examined as an option to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster. Electron beam parameters are based on experimental data (obtained at BNL) of electron beams extracted from a plasma cathode. Preliminary calculations indicate that single pass cooling is feasible; momentum spread can be reduced by more than an order of magnitude in less than one meter.

  14. Testing and Operation of the WR340 Waveguide Window in the APS Linac

    SciTech Connect (OSTI)

    Haase, Andrew

    2003-08-11T23:59:59.000Z

    The Advanced Photon Source (APS) linac high-power switching system makes extensive use of SF6 pressurized, WR340-size waveguide, incorporating waveguide switches. A tunable, extra low return loss waveguide window has been developed to support interfacing the pressurized waveguide with the original waveguide, which is under vacuum. The tunable approach is able to consistently achieve a return loss of at least 40 dB. Test and alignment methods, performance, and initial operating experience are described.

  15. Testing and operation of the WR340 waveguide window in the APS linac.

    SciTech Connect (OSTI)

    Gerlick, A. E.; Berg, S.; Goeppner, G. A.; Nassiri, A.; Pile, G.; Smith, T. L.

    2002-08-29T23:59:59.000Z

    The Advanced Photon Source (APS) linac high-power switching system makes extensive use of SF6 pressurized, WR340-size waveguide, incorporating waveguide switches. A tunable, extra low return loss waveguide window has been developed to support interfacing the pressurized waveguide with the original waveguide, which is under vacuum. The tunable approach is able to consistently achieve a return loss of at least 40 dB. Test and alignment methods, performance, and initial operating experience are described.

  16. Low-Z linac targets for low-MV gold nanoparticle radiation therapy

    SciTech Connect (OSTI)

    Tsiamas, P.; Mishra, P.; Berbeco, R. I.; Marcus, K.; Zygmanski, P., E-mail: pzygmanski@lroc.harvard.edu, E-mail: Erno-Sajo@uml.edu [Department of Radiation Oncology, Brigham and Women's Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts 02215 (United States); Cifter, F.; Sajo, E., E-mail: pzygmanski@lroc.harvard.edu, E-mail: Erno-Sajo@uml.edu [Medical Physics Program, Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, Massachusetts 01854 (United States)

    2014-02-15T23:59:59.000Z

    Purpose: To investigate the potential of low-Z/low-MV (low-Z) linac targets for gold nanoparticle radiotherapy (GNPT) and to determine the microscopic dose enhancement ratio (DER) due to GNP for the alternative beamlines. In addition, to evaluate the degradation of dose enhancement arising from the increased attenuation of x rays and larger skin dose in water for the low-MV beams compared to the standard linac. Methods: Monte Carlo simulations were used to compute dose and DER for various flattening-filter-free beams (2.5, 4, 6.5 MV). Target materials were beryllium, diamond, and tungsten-copper high-Z target. Target thicknesses were selected based on 20%, 60%, 70%, and 80% of the continuous slowing down approximation electron ranges for a given target material and energy. Evaluation of the microscopic DER was carried out for 100 nm GNP including the degradation factors due to beam attenuation. Results: The greatest increase in DER compared to the standard 6.5 MV linac was for a 2.5 MV Be-target (factor of ?2). Skin dose ranged from ?10% (Be, 6.5 MV-80%) to ?85% (Be, 2.5 MV-20%) depending on the target case. Attenuation of 2.5 MV beams at 22 cm was higher by ?75% compared with the standard beam. Taking into account the attenuation at 22 cm depth, the effective dose enhancement was up to ?60% above the DER of the high-Z target. For these cases the effective DER ranged between ?1.6 and 6 compared with the standard linac. Conclusions: Low-Z (2.5 MV) GNPT is possible even after accounting for greater beam attenuation for deep-seated tumors (22 cm) and the increased skin dose. Further, it can lead to significant sparing of normal tissue while simultaneously escalating the dose in the tumor cells.

  17. Review of a Spoke-Cavity Design Option for the RIA Driver Linac

    SciTech Connect (OSTI)

    Petr Ostroumov; Kenneth Shepard; Jean Delayen

    2005-05-16T23:59:59.000Z

    A design option for the 1.4 GV, multiple-charge-state driver linac required for the U. S. Rare Isotope Accelerator Project based on 345 MHz, 3-cell spoke-loaded cavities has been previously discussed [1]. This paper updates consideration of design options for the RIA driver, including recent results from numerically-modeling the multi-charge-state beam dynamics and also cold test results for prototype superconducting niobium 3-cell spoke-loaded cavities.

  18. Studies of a Linac Driver for a High Repetition Rate X-Ray FEL

    SciTech Connect (OSTI)

    Venturini, M.; Corlett, J.; Doolittle, L.; Filippetto, D.; Papadopoulos, C.; Penn, G.; Prosnitz, D.; Qiang, J.; Reinsch, M.; Ryne, R.; Sannibale, F.; Staples, J.; Wells, R.; Wurtele, J.; Zolotorev, M.; Zholents, A.

    2011-06-01T23:59:59.000Z

    We report on on-going studies of a superconducting CW linac driver intended to support a high repetition rate FEL operating in the soft x-rays spectrum. We present a pointdesign for a 1.8 GeV machine tuned for 300 pC bunches and delivering low-emittance, low-energy spread beams as needed for the SASE and seeded beamlines.

  19. Upgrading the Data Acquisition and Control System of the LANSCE LINAC

    SciTech Connect (OSTI)

    Baros, Dolores [Los Alamos National Laboratory

    2011-01-01T23:59:59.000Z

    Los Alamos National Laboratory LANL is in the process of upgrading the control system for the Los Alamos Neutron Science Center (LANSCE) linear accelerator. The 38 year-old data acquisition and control equipment is being replaced with COTS hardware. An overview of the current system requirements and how the National Instruments cRIO system meets these requirements will be given, as well as an update on the installation and operation of a prototype system in the LANSCE LINAC.

  20. Upgrade of the Drive LINAC for the AWA Facility Dielectric Two-Beam Accelerator

    SciTech Connect (OSTI)

    Power, John; /Argonne; Conde, Manoel; /Argonne; Gai, Wei; /Argonne; Li, Zenghai; /SLAC; Mihalcea, Daniel; /Northern Illinois U.

    2012-07-02T23:59:59.000Z

    We report on the design of a seven-cell, standing-wave, 1.3-GHz rf cavity and the associated beam dynamics studies for the upgrade of the drive beamline LINAC at the Argonne Wakefield Accelerator (AWA) facility. The LINAC design is a compromise between single-bunch operation (100 nC {at} 75 MeV) and minimization of the energy droop along the bunch train during bunch-train operation. The 1.3-GHz drive bunch-train target parameters are 75 MeV, 10-20-ns macropulse duration, and 16 x 60 nC microbunches; this is equivalent to a macropulse current and beam power of 80 A and 6 GW, respectively. Each LINAC structure accelerates approximately 1000 nC in 10 ns by a voltage of 11 MV at an rf power of 10 MW. Due to the short bunch-train duration desired ({approx}10 ns) and the existing frequency (1.3 GHz), compensation of the energy droop along the bunch train is difficult to accomplish by means of the two standard techniques: time-domain or frequency-domain beam loading compensation. Therefore, to minimize the energy droop, our design is based on a large stored energy rf cavity. In this paper, we present our rf cavity optimization method, detailed rf cavity design, and beam dynamics studies of the drive beamline.

  1. Practical Witness for Electronic Coherences

    E-Print Network [OSTI]

    Allan S. Johnson; Joel Yuen-Zhou; Alán Aspuru-Guzik; Jacob J. Krich

    2014-08-13T23:59:59.000Z

    The origin of the coherences in two-dimensional spectroscopy of photosynthetic complexes remains disputed. Recently it has been shown that in the ultrashort-pulse limit, oscillations in a frequency-integrated pump-probe signal correspond exclusively to electronic coherences, and thus such experiments can be used to form a test for electronic vs. vibrational oscillations in such systems. Here we demonstrate a method for practically implementing such a test, whereby pump-probe signals are taken at several different pulse durations and used to extrapolate to the ultrashort-pulse limit. We present analytic and numerical results determining requirements for pulse durations and the optimal choice of pulse central frequency, which can be determined from an absorption spectrum. Our results suggest that for numerous systems the required experiment could be implemented by many ultrafast spectroscopy laboratories using pulses of tens of femtoseconds in duration. Such experiments could resolve the standing debate over the nature of coherences in photosynthetic complexes.

  2. Superposed Coherent and Squeezed Light

    E-Print Network [OSTI]

    Fesseha Kassahun

    2012-01-18T23:59:59.000Z

    We first calculate the mean photon number and quadrature variance of superposed coherent and squeezed light, following a procedure of analysis based on combining the Hamiltonians and using the usual definition for the quadrature variance of superposed light beams. This procedure of analysis leads to physically unjustifiable mean photon number of the coherent light and quadrature variance of the superposed light. We then determine both of these properties employing a procedure of analysis based on superposing the Q functions and applying a slightly modified definition for the quadrature variance of a pair of superposed light beams. We find the expected mean photon number of the coherent light and the quadrature variance of the superposed light. Moreover, the quadrature squeezing of the superposed output light turns out to be equal to that of the superposed cavity light.

  3. A Compact X-Band Linac for an X-Ray FEL

    SciTech Connect (OSTI)

    Adolphsen, Chris; Huang, Zhirong; Bane, Karl L.F.; Li, Zenghai; Zhou, Feng; Wang, Faya; Nantista, Christopher D.; /SLAC

    2011-09-12T23:59:59.000Z

    With the growing demand for FEL light sources, cost issues are being reevaluated. To make the machines more compact, higher frequency room temperature linacs are being considered, specifically ones using C-band (5.7 GHz) rf technology, for which 40 MV/m gradients are achievable. In this paper, we show that an X-band (11.4 GHz) linac using the technology developed for NLC/GLC can provide an even lower cost solution. In particular, stable operation is possible at gradients of 100 MV/m for single bunch operation and 70 MV/m for multibunch operation. The concern, of course, is whether the stronger wakefields will lead to unacceptable emittance dilution. However, we show that the small emittances produced in a 250 MeV, low bunch charge, LCLS-like S-band injector and bunch compressor can be preserved in a multi-GeV X-band linac with reasonable alignment tolerances. The successful lasing and operation of the LCLS [1] has generated world-wide interest in X-ray FELs. The demand for access to such a light source by researchers eager to harness the capabilities of this new tool far exceeds the numbers that can be accommodated, spurring plans for additional facilities. Along with cost, spatial considerations become increasingly important for a hard X-ray machine driven by a multi-GeV linac. The consequent need for high acceleration gradient focuses attention on higher frequency normal conducting accelerator technology, rather than the superconducting technology of a soft X-ray facility like FLASH. C-band technology, such as used by Spring-8, is a popular option, capable of providing 40 MV/m. However, more than a decade of R&D toward an X-band linear collider, centered at SLAC and KEK, has demonstrated that this frequency option can extend the gradient reach to the 70-100 MV/m range. The following design and beam dynamics calculations show an X-band linac to be an attractive choice on which to base an X-ray FEL.

  4. Coherent scattering from a free gas

    E-Print Network [OSTI]

    Sanders, Scott N.

    We investigate decoherence in atom interferometry due to scattering from a background gas and show that the supposition that residual coherence is due to near-forward scattering is incorrect. In fact, the coherent part is ...

  5. Hanbury Brown-Twiss Experiment with Coherent

    E-Print Network [OSTI]

    39 Chapter 2 Hanbury Brown-Twiss Experiment with Coherent Light This chapter was previously a theory that allows us #12;40 Hanbury Brown-Twiss Experiment with Coherent Light to construct processes

  6. Radiation trapping in coherent media

    E-Print Network [OSTI]

    A. B. Matsko; I. Novikova; M. O. Scully; G. R. Welch

    2001-01-31T23:59:59.000Z

    We show that the effective decay rate of Zeeman coherence, generated in a Rb87 vapor by linearly polarized laser light, increases significantly with the atomic density. We explain this phenomenon as the result of radiation trapping. Our study shows that radiation trapping must be taken into account to fully understand many electromagnetically induced transparency experiments with optically thick media.

  7. Constructing matrices with optimal block coherence

    E-Print Network [OSTI]

    Thompson, Andrew

    Constructing matrices with optimal block coherence Andrew Thompson (Duke University) Joint work · Background: · The subspace packing problem · An equivalent notion: block coherence · Who is interested in this? #12;Outline · Background: · The subspace packing problem · An equivalent notion: block coherence

  8. SU-D-19A-04: Parameter Characterization of Electron Beam Monte Carlo Phase Space of TrueBeam Linacs

    SciTech Connect (OSTI)

    Rodrigues, A; Yin, F; Wu, Q [Duke University Medical Center, Durham, NC (United States); Medical Physics Graduate Program, Duke University Medical Center, Durham, NC (United States); Sawkey, D [Varian Medical Systems, Palo Alto, CA (United States)

    2014-06-01T23:59:59.000Z

    Purpose: For TrueBeam Monte Carlo simulations, Varian does not distribute linac head geometry and material compositions, instead providing a phase space file (PSF) for the users. The PSF has a finite number of particle histories and can have very large file size, yet still contains inherent statistical noises. The purpose of this study is to characterize the electron beam PSF with parameters. Methods: The PSF is a snapshot of all particles' information at a given plane above jaws including type, energy, position, and directions. This study utilized a preliminary TrueBeam PSF, of which validation against measurement is presented in another study. To characterize the PSF, distributions of energy, position, and direction of all particles are analyzed as piece-wise parameterized functions of radius and polar angle. Subsequently, a pseudo PSF was generated based on this characterization. Validation was assessed by directly comparing the true and pseudo PSFs, and by using both PSFs in the down-stream MC simulations (BEAMnrc/DOSXYZnrc) and comparing dose distributions for 3 applicators at 15 MeV. Statistical uncertainty of 4% was limited by the number of histories in the original PSF. Percent depth dose (PDD) and orthogonal (PRF) profiles at various depths were evaluated. Results: Preliminary results showed that this PSF parameterization was accurate, with no visible differences between original and pseudo PSFs except at the edge (6 cm off axis), which did not impact dose distributions in phantom. PDD differences were within 1 mm for R{sub 7} {sub 0}, R{sub 5} {sub 0}, R{sub 3} {sub 0}, and R{sub 1} {sub 0}, and PRF field size and penumbras were within 2 mm. Conclusion: A PSF can be successfully characterized by distributions for energy, position, and direction as parameterized functions of radius and polar angles; this facilitates generating sufficient particles at any statistical precision. Analyses for all other electron energies are under way and results will be included in the presentation.

  9. Control of coherent backscattering by breaking optical reciprocity

    E-Print Network [OSTI]

    Bromberg, Y; Popoff, S M; Cao, H

    2015-01-01T23:59:59.000Z

    Reciprocity is a universal principle that has a profound impact on many areas of physics. A fundamental phenomenon in condensed-matter physics, optical physics and acoustics, arising from reciprocity, is the constructive interference of quantum or classical waves which propagate along time-reversed paths in disordered media, leading to, for example, weak localization and metal-insulator transition. Previous studies have shown that such coherent effects are suppressed when reciprocity is broken. Here we show that by breaking reciprocity in a controlled manner, we can tune, rather than simply suppress, these phenomena. In particular, we manipulate coherent backscattering of light, also known as weak localization. By utilizing a non-reciprocal magneto-optical effect, we control the interference between time-reversed paths inside a multimode fiber with strong mode mixing, and realize a continuous transition from the well-known peak to a dip in the backscattered intensity. Our results may open new possibilities fo...

  10. Quantizations on the circle and coherent states

    E-Print Network [OSTI]

    Chadzitaskos, G; Tolar, J

    2012-01-01T23:59:59.000Z

    We present a possible construction of coherent states on the unit circle as configuration space. Our approach is based on Borel quantizations on S^1 including the Aharonov-Bohm type quantum description. The coherent states are constructed by Perelomov's method as group related coherent states generated by Weyl operators on the quantum phase space Z x S^1. Because of the duality of canonical coordinates and momenta, i.e. the angular variable and the integers, this formulation can also be interpreted as coherent states over an infinite periodic chain. For the construction we use the analogy with our quantization and coherent states over a finite periodic chain where the quantum phase space was Z_M x Z_M. The coherent states constructed in this work are shown to satisfy the resolution of unity. To compare them with canonical coherent states, also some of their further properties are studied demonstrating similarities as well as substantial differences.

  11. Temperature control feedback loops for the linac upgrade side coupled cavities at Fermilab

    SciTech Connect (OSTI)

    Crisp, J.

    1990-10-25T23:59:59.000Z

    The linac upgrade project at Fermilab will replace the last 4 drift-tube linac tanks with seven side coupled cavity strings. This will increase the beam energy from 200 to 400 MeV at injection into the Booster accelerator. The main objective of the temperature loop is to control the resonant frequency of the cavity strings. A cavity string will constant of 4 sections connected with bridge couplers driven with a 12 MW klystron at 805 MHz. Each section is a side coupled cavity chain consisting of 16 accelerating cells and 15 side coupling cells. For the linac upgrade, 7 full cavity strings will be used. A separate temperature control system is planned for each of the 28 accelerating sections, the two transition sections, and the debuncher section. The cavity strings will be tuned to resonance for full power beam loaded conditions. A separate frequency loop is planned that will sample the phase difference between a monitor placed in the end cell of each section and the rf drive. The frequency loop will control the set point for the temperature loop which will be able to maintain the resonant frequency through periods within beam or rf power. The frequency loop will need the intelligence required to determine under what conditions the phase error information is valid and the temperature set point should be adjusted. This paper will discuss some of the reason for temperature control, the implementation, and some of the problems encountered. An appendix contains some useful constants and descriptions of some of the sensor and control elements used. 13 figs.

  12. Evaluation of radiosurgery techniques–Cone-based linac radiosurgery vs tomotherapy-based radiosurgery

    SciTech Connect (OSTI)

    Yip, Ho Yin, E-mail: hoyinyip@yahoo.com.hk [Department of Radiotherapy, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong (China); Mui, Wing Lun A.; Lee, Joseph W.Y.; Fung, Winky Wing Ki; Chan, Jocelyn M.T.; Chiu, G. [Department of Radiotherapy, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong (China); Law, Maria Y.Y. [Medical Physics and Research Department, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong (China)

    2013-07-01T23:59:59.000Z

    Performances of radiosurgery of intracranial lesions between cone-based Linac system and Tomotherapy-based system were compared in terms of dosimetry and time. Twelve patients with single intracranial lesion treated with cone-based Linac radiosurgery system from 2005 to 2009 were replanned for Tomotherapy-based radiosurgery treatment. The conformity index, homogeneity index (HI), and gradient score index (GSI) of each case was calculated. The Wilcoxon matched-pair test was used to compare the 3 indices between both systems. The cases with regular target (n = 6) and those with irregular target (n = 6) were further analyzed separately. The estimated treatment time between both systems was also compared. Significant differences were found in HI (p = 0.05) and in GSI (p = 0.03) for the whole group. Cone-based radiosurgery was better in GSI whereas Tomotherapy-based radiosurgery was better in HI. Cone-based radiosurgery was better in conformity index (p = 0.03) and GSI (p = 0.03) for regular targets, whereas Tomotherapy-based radiosurgery system performed significantly better in HI (p = 0.03) for irregular targets. The estimated total treatment time for Tomotherapy-based radiosurgery ranged from 24 minutes to 35 minutes, including 15 minutes of pretreatment megavoltage computed tomography (MVCT) and image registration, whereas that for cone-based radiosurgery ranged from 15 minutes for 1 isocenter to 75 minutes for 5 isocenters. As a rule of thumb, Tomotherapy-based radiosurgery system should be the first-line treatment for irregular lesions because of better dose homogeneity and shorter treatment time. Cone-based Linac radiosurgery system should be the treatment of choice for regular targets because of the better dose conformity, rapid dose fall-off, and reasonable treatment time.

  13. Energy Recovery Linac cavity at BNL | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurTheBrookhaven NationalRegionalsResearch » Climate andEnergy Recovery Linac

  14. Quantum learning of coherent states

    E-Print Network [OSTI]

    Gael Sentís; Madalin Guta; Gerardo Adesso

    2014-10-31T23:59:59.000Z

    We develop a quantum learning scheme for binary discrimination of coherent states of light. This is a problem of technological relevance for the reading of information stored in a digital memory. In our setting, a coherent light source is used to illuminate a memory cell and retrieve its encoded bit by determining the quantum state of the reflected signal. We consider a situation where the amplitude of the states produced by the source is not fully known, but instead this information is encoded in a large training set comprising many copies of the same coherent state. We show that an optimal global measurement, performed jointly over the signal and the training set, provides higher successful identification rates than any learning strategy based on first estimating the unknown amplitude by means of Gaussian measurements on the training set, followed by an adaptive discrimination procedure on the signal. By considering a simplified variant of the problem, we argue that this is the case even for non-Gaussian estimation measurements. Our results show that, even in absence of entanglement, collective quantum measurements yield an enhancement in the readout of classical information, which is particularly relevant in the operating regime of low-energy signals.

  15. H- Beam Loss and Evidence for Intrabeam Stripping in the LANSCE Linac

    SciTech Connect (OSTI)

    Rybarcyk, Lawrence J. [Los Alamos National Laboratory; Kelsey, Charles T. IV [Los Alamos National Laboratory; McCrady, Rodney C. [Los Alamos National Laboratory; Pang, Xiaoying [Los Alamos National Laboratory

    2012-05-15T23:59:59.000Z

    The LANSCE accelerator complex is a multi-beam, multi-user facility that provides high-intensity H{sup +} and H{sup -} particle beams for a variety of user programs. At the heart of the facility is a room temperature linac that is comprised of 100-MeV drift tube and 800-MeV coupled cavity linac (CCL) structures. Although both beams are similar in intensity and emittance at 100 MeV, the beam-loss monitors along the CCL show a trend of increased loss for H{sup -} that is not present for H{sup +}. This difference is attributed to stripping mechanisms that affect H{sup -} and not H{sup +}. We present the results of an analysis of H{sup -} beam loss along the CCL that incorporates beam spill measurements, beam dynamics simulations, analytical models and radiation transport estimates using the MCNPX code. The results indicate a significant fraction of these additional losses result from intrabeam stripping.

  16. Apparatus for generating partially coherent radiation

    DOE Patents [OSTI]

    Naulleau, Patrick P.

    2004-09-28T23:59:59.000Z

    The effective coherence of an undulator beamline can be tailored to projection lithography requirements by using a simple single moving element and a simple stationary low-cost spherical mirror. The invention is particularly suited for use in an illuminator device for an optical image processing system requiring partially coherent illumination. The illuminator includes: (i) source of coherent or partially coherent radiation which has an intrinsic coherence that is higher than the desired coherence; (ii) a reflective surface that receives incident radiation from said source; (iii) means for moving the reflective surface through a desired range of angles in two dimensions wherein the rate of the motion is fast relative to integration time of said image processing system; and (iv) a condenser optic that re-images the moving reflective surface to the entrance plane of said image processing system, thereby, making the illumination spot in said entrance plane essentially stationary.

  17. Does coherence enhance transport in photosynthesis?

    E-Print Network [OSTI]

    Ivan Kassal; Joel Yuen-Zhou; Saleh Rahimi-Keshari

    2012-10-18T23:59:59.000Z

    Recent observations of coherence in photosynthetic complexes have led to the question of whether quantum effects can occur in vivo, not under femtosecond laser pulses but in incoherent sunlight and at steady state, and, if so, whether the coherence explains the high exciton transfer efficiency. We distinguish several types of coherence and show that although some photosynthetic pathways are partially coherent processes, photosynthesis in nature proceeds through stationary states. This distinction allows us to rule out several mechanisms of transport enhancement in sunlight. In particular, although they are crucial for understanding exciton transport, neither wavelike motion nor microscopic coherence, on their own, enhance the efficiency. By contrast, two partially coherent mechanisms---ENAQT and supertransfer---can enhance transport even in sunlight and thus constitute motifs for the optimisation of artificial sunlight harvesting. Finally, we clarify the importance of ultrafast spectroscopy in understanding incoherent processes.

  18. Does coherence enhance transport in photosynthesis?

    E-Print Network [OSTI]

    Kassal, Ivan; Rahimi-Keshari, Saleh

    2012-01-01T23:59:59.000Z

    Recent observations of coherence in photosynthetic complexes have led to the question of whether quantum effects can occur in vivo, not under femtosecond laser pulses but in incoherent sunlight and at steady state, and, if so, whether the coherence explains the high exciton transfer efficiency. We distinguish several types of coherence and show that although some photosynthetic pathways are partially coherent processes, photosynthesis in nature proceeds through stationary states. This distinction allows us to rule out several mechanisms of transport enhancement in sunlight. In particular, although they are crucial for understanding exciton transport, neither wavelike motion nor microscopic coherence, on their own, enhance the efficiency. By contrast, two partially coherent mechanisms---ENAQT and supertransfer---can enhance transport even in sunlight and thus constitute motifs for the optimisation of artificial sunlight harvesting. Finally, we clarify the importance of ultrafast spectroscopy in understanding i...

  19. Decoherence of multimode thermal squeezed coherent states

    SciTech Connect (OSTI)

    Yeh, L.

    1992-08-14T23:59:59.000Z

    It is well known that any multimode positive definite quadratic Hamiltonian can be transformed into a hamiltonian of uncoupled harmonic oscillators. Based on this theorem, the multimode thermal squeezed coherent states are constructed in terms of density operators. Decoherence of multimode thermal squeezed coherent states in investigated via the characteristic function and it is shown that the decohered (reduced) states are still thermal squeezed coherent states in general.

  20. Coherent states for the nonlinear harmonic oscillator

    SciTech Connect (OSTI)

    Ghosh, Subir [Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 B. T. Road, Kolkata 700108 (India)

    2012-06-15T23:59:59.000Z

    Wave packets for the quantum nonlinear oscillator are considered in the generalized coherent state framework. To first order in the nonlinearity parameter the coherent state behaves very similar to its classical counterpart. The position expectation value oscillates in a simple harmonic manner. The energy-momentum uncertainty relation is time independent as in a harmonic oscillator. Various features (such as the squeezed state nature) of the coherent state have been discussed.

  1. Coherent Radio Pulses From GEANT Generated Electromagnetic Showers In Ice

    E-Print Network [OSTI]

    Soebur Razzaque; Surujhdeo Seunarine; David Z. Besson; Douglas W. McKay; John P. Ralston; David Seckel

    2002-02-25T23:59:59.000Z

    Radio Cherenkov radiation is arguably the most efficient mechanism for detecting showers from ultra-high energy particles of 1 PeV and above. Showers occuring in Antarctic ice should be detectable at distances up to 1 km. We report on electromagnetic shower development in ice using a GEANT Monte Carlo simulation. We have studied energy deposition by shower particles and determined shower parameters for several different media, finding agreement with published results where available. We also report on radio pulse emission from the charged particles in the shower, focusing on coherent emission at the Cherenkov angle. Previous work has focused on frequencies in the 100 MHz to 1 GHz range. Surprisingly, we find that the coherence regime extends up to tens of Ghz. This may have substantial impact on future radio-based neutrino detection experiments as well as any test beam experiment which seeks to measure coherent Cherenkov radiation from an electromagnetic shower. Our study is particularly important for the RICE experiment at the South Pole.

  2. Optimization Online - On the Coherent Risk Measure ...

    E-Print Network [OSTI]

    KEREM UGURLU

    2014-11-25T23:59:59.000Z

    Nov 25, 2014 ... Abstract: We give a complete characterization of both comonotone and not comonotone coherent risk measures in the discrete finite probability ...

  3. Influence of coherent Raman scattering on coherent population trapping in atomic sodium vapor

    SciTech Connect (OSTI)

    Wong, Vincent; Bennink, Ryan S.; Marino, Alberto M.; Boyd, Robert W.; Stroud, C.R. Jr.; Narducci, F.A. [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); EO Sensors Division, Naval Air Systems Command, Patuxent River, Maryland 20670 (United States)

    2004-11-01T23:59:59.000Z

    We study how coherent Stokes and anti-Stokes Raman scattering influence coherent population trapping. In an experiment using an atomic sodium vapor cell we observe induced transparency, induced absorption, and gain features, all of subnatural linewidth. The electromagnetically induced resonance is a peak or a dip depending on which side of the optical transition the fields are tuned to, and thus whether coherent anti-Stokes Raman scattering or coherent Stokes Raman scattering is the dominant process.

  4. Coherent Control of Quantum Matter

    SciTech Connect (OSTI)

    Cavalleri, Andrea (Max Planck Institute) [Max Planck Institute

    2011-10-05T23:59:59.000Z

    This talk addresses some recent work aimed at controlling the low-lying electrodynamics of quantum solids using strong field transients. The excitation of selected vibrational resonances to manipulate the many-body physics of one dimensional Mott Hubbard Insulators and to perturb competing orders in High-Tc superconductors is also covered. Finally, the speaker shows how the electrodynamics of layered superconductors can be driven through the orderparameter phase gradient, demonstrating ultrafast transistor action in a layered superconductor. Advances in the use of coherent optics, from tabletop sources to THz and x-ray free-electron lasers are also discussed.

  5. Coherent instabilities in random lasers

    SciTech Connect (OSTI)

    Andreasen, Jonathan; Sebbah, Patrick; Vanneste, Christian [Laboratoire de Physique de la Matiere Condensee, CNRS UMR 6622, Universite de Nice-Sophia Antipolis, Parc Valrose, F-06108, Nice Cedex 02 (France)

    2011-08-15T23:59:59.000Z

    A numerical study is presented of random lasers as a function of the pumping rate above the threshold for lasing. Depending on the leakiness of the system resonances, which is typically larger in random lasers compared to conventional lasers, we observe that the stationary lasing regime becomes unstable above a second threshold. Coherent instabilities are observed as self pulsation at a single frequency of the output intensity, population inversion, as well as the atomic polarization. We find these Rabi oscillations have the same frequency everywhere in the random laser despite the fact that the field intensity strongly depends on the spatial location.

  6. Coherent Inc | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand JumpConceptual Model, clickInformationNew York: EnergyCoeur d Alene Fiber FuelsCoherent Inc Jump

  7. Optical coherence domain reflectometry guidewire

    DOE Patents [OSTI]

    Colston, Billy W. (Livermore, CA); Everett, Matthew (Pleasanton, CA); Da Silva, Luiz B. (Danville, CA); Matthews, Dennis (Moss Beach, CA)

    2001-01-01T23:59:59.000Z

    A guidewire with optical sensing capabilities is based on a multiplexed optical coherence domain reflectometer (OCDR), which allows it to sense location, thickness, and structure of the arterial walls or other intra-cavity regions as it travels through the body during minimally invasive medical procedures. This information will be used both to direct the guidewire through the body by detecting vascular junctions and to evaluate the nearby tissue. The guidewire contains multiple optical fibers which couple light from the proximal to distal end. Light from the fibers at the distal end of the guidewire is directed onto interior cavity walls via small diameter optics such as gradient index lenses and mirrored corner cubes. Both forward viewing and side viewing fibers can be included. The light reflected or scattered from the cavity walls is then collected by the fibers, which are multiplexed at the proximal end to the sample arm of an optical low coherence reflectometer. The guidewire can also be used in nonmedical applications.

  8. Automated x-ray/light field congruence using the LINAC EPID panel

    SciTech Connect (OSTI)

    Polak, Wojciech [Department of Medical Physics, Royal Surrey County Hospital, Guildford GU2 7XX (United Kingdom); Department of Medical Physics, Radiotherapy Section, Queen Alexandra Hospital NHS Trust, Portsmouth PO6 3LY (United Kingdom); O'Doherty, Jim [Division of Imaging Sciences and Biomedical Engineering, King's College London, London SE1 7EH, United Kingdom and Department of Medical Physics, Royal Surrey County Hospital, Guildford GU2 7XX (United Kingdom); Jones, Matt [Department of Medical Physics, Royal Surrey County Hospital, Guildford GU2 7XX (United Kingdom)

    2013-03-15T23:59:59.000Z

    Purpose: X-ray/light field alignment is a test described in many guidelines for the routine quality control of clinical linear accelerators (LINAC). Currently, the gold standard method for measuring alignment is through utilization of radiographic film. However, many modern LINACs are equipped with an electronic portal imaging device (EPID) that may be used to perform this test and thus subsequently reducing overall cost, processing, and analysis time, removing operator dependency and the requirement to sustain the departmental film processor. Methods: This work describes a novel method of utilizing the EPID together with a custom inhouse designed jig and automatic image processing software allowing measurement of the light field size, x-ray field size, and congruence between them. The authors present results of testing the method for aS1000 and aS500 Varian EPID detectors for six LINACs at a range of energies (6, 10, and 15 MV) in comparison with the results obtained from the use of radiographic film. Results: Reproducibility of the software in fully automatic operation under a range of operating conditions for a single image showed a congruence of 0.01 cm with a coefficient of variation of 0. Slight variation in congruence repeatability was noted through semiautomatic processing by four independent operators due to manual marking of positions on the jig. Testing of the methodology using the automatic method shows a high precision of 0.02 mm compared to a maximum of 0.06 mm determined by film processing. Intraindividual examination of operator measurements of congruence was shown to vary as much as 0.75 mm. Similar congruence measurements of 0.02 mm were also determined for a lower resolution EPID (aS500 model), after rescaling of the image to the aS1000 image size. Conclusions: The designed methodology was proven to be time efficient, cost effective, and at least as accurate as using the gold standard radiographic film. Additionally, congruence testing can be easily performed for all four cardinal gantry angles which can be difficult when using radiographic film. Therefore, the authors propose it can be used as an alternative to the radiographic film method allowing decommissioning of the film processor.

  9. Coherence in natural language : data structures and applications

    E-Print Network [OSTI]

    Wolf, Florian, 1975-

    2005-01-01T23:59:59.000Z

    (cont.) baseline, and that some coherence-based approaches best predict the human data. However, coherence-based algorithms that operate on trees did not perform as well as coherence-based algorithms that operate on more ...

  10. Coherent Manipulation of Coupled Electron Spins in

    E-Print Network [OSTI]

    Petta, Jason

    to control quantum systems in the solid state is a major challenge of modern condensed-matter physics (5, 6. Gossard3 We demonstrated coherent control of a quantum two-level system based on two-electron spin states) based on two-electron spin states (14) and demonstrate coherent control of this system through the use

  11. Can Natural Sunlight Induce Coherent Exciton Dynamics?

    E-Print Network [OSTI]

    Jan Olšina; Arend G. Dijkstra; Chen Wang; Jianshu Cao

    2014-08-21T23:59:59.000Z

    Excitation of a model photosynthetic molecular aggregate by incoherent sunlight is systematically examined. For a closed system, the excited state coherence induced by the sunlight oscillates with an average amplitude that is inversely proportional to the excitonic gap, and reaches a stationary amplitude that depends on the temperature and coherence time of the radiation field. For an open system, the light-induced dynamical coherence relaxes to a static coherence determined by the non-canonical thermal distribution resulting from the entanglement with the phonon bath. The decay of the excited state population to the common ground state establishes a non-equilibrium steady-state flux driven by the sunlight, and it defines a time window to observe the transition from dynamical to static coherence. For the parameters relevant to photosynthetic systems, the exciton dynamics initiated by the sunlight exhibits a non-negligible amount of dynamical coherence (quantum beats) on the sub-picosecond timescale; however, this sub-picosecond time-scale is long enough for light-harvesting systems to establish static coherence, which plays a crucial role in efficient energy transfer. Further, a relationship is established between the non-equilibrium steady-state induced by the sunlight and the coherent dynamics initiated from the ground state by a laser $\\delta$-pulse, thereby making a direct connection between incoherent sunlight excitation and ultrafast spectroscopy.

  12. Coherent state quantization of paragrassmann algebras

    E-Print Network [OSTI]

    M. El Baz; R. Fresneda; J. P. Gazeau; Y. Hassouni

    2011-12-30T23:59:59.000Z

    By using a coherent state quantization of paragrassmann variables, operators are constructed in finite Hilbert spaces. We thus obtain in a straightforward way a matrix representation of the paragrassmann algebra. This algebra of finite matrices realizes a deformed Weyl-Heisenberg algebra. The study of mean values in coherent states of some of these operators lead to interesting conclusions.

  13. The Fidelity and Trace Norm Distances for Quantifying Coherence

    E-Print Network [OSTI]

    Lian-He Shao; Zhengjun Xi; Heng Fan; Yongming Li

    2014-10-30T23:59:59.000Z

    We investigate the coherence measures induced by fidelity and trace norm, based on the recent proposed coherence quantification in [Phys. Rev. Lett. 113, 140401, 2014]. We show that the fidelity of coherence does not in general satisfy the monotonicity requirement as a measure of coherence under the subselection of measurements condition. We find that the trace norm of coherence can act as a measure of coherence for qubit case and some special class of qutrits.

  14. Plasma ignition and steady state simulations of the Linac4 H$^{-}$ ion source

    E-Print Network [OSTI]

    Mattei, S; Yasumoto, M; Hatayama, A; Lettry, J; Grudiev, A

    2013-01-01T23:59:59.000Z

    The RF heating of the plasma in the Linac4 H- ion source has been simulated using an Particle-in-Cell Monte Carlo Collision method (PIC-MCC). This model is applied to investigate the plasma formation starting from an initial low electron density of 1012 m-3 and its stabilization at 1018 m-3. The plasma discharge at low electron density is driven by the capacitive coupling with the electric field generated by the antenna, and as the electron density increases the capacitive electric field is shielded by the plasma and induction drives the plasma heating process. Plasma properties such as e-/ion densities and energies, sheath formation and shielding effect are presented and provide insight to the plasma properties of the hydrogen plasma.

  15. Longitudinal Dynamics of Twin Electron Bunches in a High-energy Linac

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Zhen; Ding, Yuantao; Marinelli, Agostino; Huang, Zhirong

    2015-03-01T23:59:59.000Z

    The recent development of two-color x-ray free-electron lasers, as well as the successful demonstration of high-gradient witness bunch acceleration in a plasma, have generated strong interest in electron bunch trains, where two or more electron bunches are generated, accelerated and compressed in the same accelerating bucket. In this paper we give a detailed analysis of a twin-bunch technique in a high-energy linac. This method allows the generation of two electron bunches with high peak current and independent control of time delay and energy separation. We #12;find that the wake#12;fields in the accelerator structures play an important role in the twin-bunch compression, and through analysis show that they can be used to extend the available time delay range. Based on the theoretical model and simulations we propose several methods to achieve larger time delay.

  16. Comparative Wakefield Analysis of a First Prototype of a DDS Structure for CLIC Main Linac

    E-Print Network [OSTI]

    D'Elia, A; Khan, V F; Grudiev, A; Wuensch, W

    2011-01-01T23:59:59.000Z

    A Damped Detuned Structure (DDS) for CLIC main linac has been proposed as an alternative to the present baseline design which is based on heavy damping. A first prototype, CLIC_DDS_A, for high power tests has been already designed and is under construction. It is also foreseen to design a further prototype, CLIC_DDS_B, to test both the wakefield suppression and high power performances. Wakefield calculations for DDS are, in the early design stage, based on single infinitely periodic cells. Though cell-to-cell interaction is taken into account to calculate the wakefields, it is important to study full structure properties using computational tools. In particular this is fundamental for defining the input parameters for the HOM coupler that is crucial for the performances of DDS. In the following a full analysis of wakefields and impedances based on simulations conducted with finite difference based electromagnetic computer code GdfidL will be presented.

  17. GEANT4 Application for the Simulation of the Head of a Siemens Primus Linac

    SciTech Connect (OSTI)

    Cortes-Giraldo, M. A.; Quesada, J. M.; Gallardo, M. I. [Dep. Fisica Atomica, Molecular y Nuclear, University of Sevilla. Apdo. 1065 E-41080 Sevilla (Spain)

    2010-04-26T23:59:59.000Z

    The Monte Carlo simulation of the head of a Siemens Primus Linac used at Virgen Macarena Hospital (Sevilla, Spain) has been performed using the code GEANT4, version 9.2. In this work, the main features of the application built by our group are presented. They are mainly focused in the optimization of the performance of the simulation. The geometry, including the water phantom, has been entirely wrapped by a shielding volume which discards all the particles escaping far away through its walls. With this, a factor of four in the time spent by the simulation can be saved. An interface to read and write phase-space files in IAEA format has been also developed to save CPU time in our simulations. Finally, some calculations of the dose absorption in the water phantom have been done and compared with the results given by EGSnrc and with experimental data obtained for the calibration of the machine.

  18. Industrial Fabrication of Medium-Beta SCRF Cavities for a High-Intensity Proton Linac

    E-Print Network [OSTI]

    Kuzminski, J; Gentzlinger, R C; Maccioni, P

    2000-01-01T23:59:59.000Z

    During 1999, four 700-MHz, medium-beta (b = 0.64), superconducting radio frequency (SCRF) cavities for a high-intensity proton linac project at Los Alamos National Laboratory (LANL) were manufactured by industry. The SCRF cavities were designed by a LANL team in Los Alamos, New Mexico, USA, and manufactured at a CERCA plant in Romans, France. The cavities were made of 4-mm-thick, solid niobium sheets with a residual resistivity ratio (RRR) greater than 250. These niobium sheets were supplied by Wah Chang (USA), Heraeus AG (Germany), and Tokyo Denkai (Japan). The SCRF cavities were shipped to LANL for performance testing. This paper describes the experience gained during the manufacturing process at CERCA.

  19. PROCEEDING OF WORKSHOP ON PHOTO-INJECTOR FOR ENERGY RECOVERY LINAC.

    SciTech Connect (OSTI)

    WANG,X.J.

    2001-01-22T23:59:59.000Z

    Workshop on Photo-injectors for Energy Recovery Linac was held at National Synchrotron Light Source (NSLS) of Brookhaven National Laboratory (BNL) on January 22 and 23, 2001. Fifty people attended the workshop; they came from three countries, representing universities, industries and national laboratories. This is the first workshop ever held on photo-injectors for CW operation, and for the first time, both DC and RF photo-injectors were discussed at the workshop. Workshop covered almost all major issues of photo-injectors, photocathode, laser system, vacuum, DC, 433 MHz/B-factory cavities based RF gun, 1.3 GHz RF gun and beam instrumentation. High quantum efficiency and long live time photocathode is the issue discussed during the workshop. Four working group leaders have done great jobs summarizing the workshop discussion, and identifying the major issues for future R and D.

  20. A wire scanner system for characterizing the BNL energy recovery LINAC beam position monitor system

    SciTech Connect (OSTI)

    Michnoff R.; Biscardi, C.; Cerniglia, P.; Degen, C.; Gassner, D.; Hoff, L.; Hulsart, R.

    2012-04-15T23:59:59.000Z

    A stepper motor controlled wire scanner system has recently been modified to support testing of the Brookhaven National Laboratory (BNL) Collider-Accelerator department's Energy Recovery Linac (ERL) beam position monitor (BPM) system. The ERL BPM consists of four 9.33 mm diameter buttons mounted at 90 degree spacing in a cube with 1.875 inch inside diameter. The buttons were designed by BNL and fabricated by Times Microwave Systems. Libera brilliance single pass BPM electronic modules with 700 MHz bandpass filter, manufactured by Instrumentation Technologies, will be used to measure the transverse beam positions at 14 locations around the ERL. The wire scanner assembly provides the ability to measure the BPM button response to a pulsed wire, and evaluate and calibrate the Libera position measurement electronics. A description of the wire scanner system and test result data will be presented.

  1. An 800-MeV superconducting LINAC to support megawatt proton operations at Fermilab

    E-Print Network [OSTI]

    Derwent, Paul; Lebedev, Valeri

    2015-01-01T23:59:59.000Z

    Active discussion on the high energy physics priorities in the US carried out since summer of 2013 resulted in changes in Fermilab plans for future development of the existing accelerator complex. In particular, the scope of Project X was reduced to the support of the Long Base Neutrino Facility (LBNF) at the project first stage. The name of the facility was changed to the PIP-II (Proton Improvement Plan). This new facility is a logical extension of the existing Proton Improvement Plan aimed at doubling average power of the Fermilab's Booster and Main Injector (MI). Its design and required R&D are closely related to the Project X. The paper discusses the goals of this new facility and changes to the Project X linac introduced to support the goals.

  2. The machine protection system for the R&D energy recovery LINAC

    SciTech Connect (OSTI)

    Altinbas, Z.; Kayran, D.; Jamilkowski, J.; Lee, R.C.; Oerter, B.

    2011-03-28T23:59:59.000Z

    The Machine Protection System (MPS) is a device-safety system that is designed to prevent damage to hardware by generating interlocks, based upon the state of input signals generated by selected sub-systems. It protects all the key machinery in the R&D Project called the Energy Recovery LINAC (ERL) against the high beam current. The MPS is capable of responding to a fault with an interlock signal within several microseconds. The ERL MPS is based on a National Instruments CompactRIO platform, and is programmed by utilizing National Instruments' development environment for a visual programming language. The system also transfers data (interlock status, time of fault, etc.) to the main server. Transferred data is integrated into the pre-existing software architecture which is accessible by the operators. This paper will provide an overview of the hardware used, its configuration and operation, as well as the software written both on the device and the server side.

  3. Longitudinal Dynamics of Twin Electron Bunches in a High-energy Linac

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Zhen; Tsinghua University, Beijing; Ding, Yuantao; Marinelli, Agostino; Huang, Zhirong

    2015-03-01T23:59:59.000Z

    The recent development of two-color x-ray free-electron lasers, as well as the successful demonstration of high-gradient witness bunch acceleration in a plasma, have generated strong interest in electron bunch trains, where two or more electron bunches are generated, accelerated and compressed in the same accelerating bucket. In this paper we give a detailed analysis of a twin-bunch technique in a high-energy linac. This method allows the generation of two electron bunches with high peak current and independent control of time delay and energy separation. We #12;find that the wake#12;fields in the accelerator structures play an important role in the twin-bunchmore »compression, and through analysis show that they can be used to extend the available time delay range. Based on the theoretical model and simulations we propose several methods to achieve larger time delay.« less

  4. Coherent Quantum Dynamics: What Fluctuations Can Tell

    E-Print Network [OSTI]

    Schliemann, John

    2015-01-01T23:59:59.000Z

    Coherent states provide a natural connection of quantum systems to their classical limit and are employed in various fields of physics. Here we derive general systematic expansions, with respect to quantum parameters, of expectation values of products of arbitrary operators within both oscillator coherent states and SU(2) coherent states. In particular, we generally prove that the energy fluctuations of an arbitrary Hamiltonian are in leading order entirely due to the time dependence of the classical variables. These results add to the list of wellknown properties of coherent states and are applied here to the Lipkin-Meshkov-Glick model, the Dicke model, and to coherent intertwiners in spin networks as considered in Loop Quantum Gravity.

  5. aligning coherent bremsstrahlung: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    internal state of the plant. Importantly, coherent observers avoid measurements of the plant outputs. We compare our coherent observers with a classical (measurement-based)...

  6. CIRCE: A dedicated storage ring for coherent THz synchrotron radiation

    E-Print Network [OSTI]

    2003-01-01T23:59:59.000Z

    High-power terahertz radiation from relativistic electrons",coherent THz synchrotron radiation: Measuring the Josephsonof coherent synchrotron radiation from the NSLS VUV ring",

  7. Quantum Coherence Arguments for Cosmological Scale

    SciTech Connect (OSTI)

    Lindesay, James; /SLAC

    2005-05-27T23:59:59.000Z

    Homogeneity and correlations in the observed CMB are indicative of some form of cosmological coherence in early times. Quantum coherence in the early universe would be expected to give space-like phase coherence to any effects sourced to those times. If dark energy de-coherence is assumed to occur when the rate of expansion of the relevant cosmological scale parameter in the Friedmann-Lemaitre equations is no longer supra-luminal, a critical energy density is immediately defined. It is shown that the general class of dynamical models so defined necessarily requires a spatially flat cosmology in order to be consistent with observed structure formation. The basic assumption is that the dark energy density which is fixed during de-coherence is to be identified with the cosmological constant. It is shown for the entire class of models that the expected amplitude of fluctuations driven by the dark energy de-coherence process is of the order needed to evolve into the fluctuations observed in cosmic microwave background radiation and galactic clustering. The densities involved during de-coherence which correspond to the measured dark energy density turn out to be of the electroweak symmetry restoration scale. In an inflationary cosmology, this choice of the scale parameter in the FL equations directly relates the scale of dark energy decoherence to the De Sitter scales (associated with the positive cosmological constants) at both early and late times.

  8. Lorentz Coherence and the Proton Form Factor

    E-Print Network [OSTI]

    Kim, Young S

    2015-01-01T23:59:59.000Z

    The dipole cutoff behavior for the proton form factor has been and still is one of the major issues in high-energy physics. It is shown that this dipole behavior comes from the coherence between the Lorentz contraction of the proton size and the decreasing wavelength of the incoming photon signal. The contraction rates are the same for both cases. This form of coherence is studied also in the momentum-energy space. The coherence effect in this space can be explained in terms of two overlapping wave functions.

  9. Lorentz Coherence and the Proton Form Factor

    E-Print Network [OSTI]

    Young S. Kim

    2015-02-28T23:59:59.000Z

    The dipole cutoff behavior for the proton form factor has been and still is one of the major issues in high-energy physics. It is shown that this dipole behavior comes from the coherence between the Lorentz contraction of the proton size and the decreasing wavelength of the incoming photon signal. The contraction rates are the same for both cases. This form of coherence is studied also in the momentum-energy space. The coherence effect in this space can be explained in terms of two overlapping wave functions.

  10. Asymmetric Cache Coherency: Policy Modifications to Improve Multicore Performance

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    coherency policy, generated a 60% coherency cost reduction (reduction of latencies due to coherency messages-Sud Guy Gogniat, Lab-STICC, Universit´e de Bretagne-Sud Asymmetric coherency is a new optimisation method page or initial screen of a display along with the full citation. Copyrights for components

  11. Issues concerning high current lower energy electron beams required for ion cooling between EBIS LINAC and booster

    SciTech Connect (OSTI)

    Hershcovitch,A.

    2009-03-01T23:59:59.000Z

    Some issues, regarding a low energy high current electron beam that will be needed for electron beam cooling to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster, are examined. Options for propagating such an electron beam, as well as the effect of neutralizing background plasma on electron and ion beam parameters are calculated. Computations and some experimental data indicate that none of these issues is a show stopper.

  12. Production and application of a novel energy-tunable X-ray source at the RPI LINAC

    E-Print Network [OSTI]

    Danon, Yaron

    Production and application of a novel energy-tunable X-ray source at the RPI LINAC Bryndol Sones energy linewidth for example, Si(400) FWHM of 134 eV at 9.0 keV (2%). Per electron, the photon production 17­20 keV. Low Z materials like graphite and LiF were most suitable for PXR production because

  13. CALIBRATION, COHERENCE, AND SCORING RULES* TEDDY SEIDENFELDt

    E-Print Network [OSTI]

    Fitelson, Branden

    CALIBRATION, COHERENCE, AND SCORING RULES* TEDDY SEIDENFELDt Department of Philosophy Washington, I focus on one such aspirant: calibration. Cal- ibration requires an alignment of announced: (i) Surveys designed to display calibration curves, from which a recalibration is to be calculated

  14. Coherent regulation in yeast cell cycle network

    E-Print Network [OSTI]

    Nese Aral; Alkan Kabakcioglu

    2014-12-14T23:59:59.000Z

    We define a measure of coherent activity for gene regulatory networks, a property that reflects the unity of purpose between the regulatory agents with a common target. We propose that such harmonious regulatory action is desirable under a demand for energy efficiency and may be selected for under evolutionary pressures. We consider two recent models of the cell-cycle regulatory network of the budding yeast, Saccharomyces cerevisiae, as a case study and calculate their degree of coherence. A comparison with random networks of similar size and composition reveals that the yeast's cell-cycle regulation is wired to yield and exceptionally high level of coherent regulatory activity. We also investigate the mean degree of coherence as a function of the network size, connectivity and the fraction of repressory/activatory interactions.

  15. Coherent Control of Photoelectron Wavepacket Angular Interferograms

    E-Print Network [OSTI]

    Hockett, Paul; Baumert, Thomas

    2015-01-01T23:59:59.000Z

    Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the coherent control over the resultant photoelectron interferogram is thus explored in detail. Based on this understanding, the use of coherent control with polarization-shaped pulses as a methodology for a highly multiplexed coherent quantum metrology is also investigated, and defined in terms of the information content of the observable.

  16. Coherence properties of the radiation from FLASH

    E-Print Network [OSTI]

    Schneidmiller, E A

    2015-01-01T23:59:59.000Z

    FLASH is the first free electron laser user facility operating in the vacuum ultraviolet and soft x-ray wavelength range. Many user experiments require knowledge of the spatial and temporal coherence properties of the radiation. In this paper we present an analysis of the coherence properties of the radiation for the fundamental and for the higher odd frequency harmonics. We show that temporal and spatial coherence reach maximum close to the FEL saturation but may degrade significantly in the post-saturation regime. We also find that the pointing stability of short FEL pulses is limited due to the fact that non-azimuthal FEL eigenmodes are not sufficiently suppressed. We discuss possible ways for improving the degree of transverse coherence and the pointing stability.

  17. The extraction of work from quantum coherence

    E-Print Network [OSTI]

    Kamil Korzekwa; Matteo Lostaglio; Jonathan Oppenheim; David Jennings

    2015-06-25T23:59:59.000Z

    We critically assess the problem of extracting work from a coherent superposition of energy eigenstates of an individual qubit system. By carefully taking into account all the resources involved in the thermodynamic transformations in a fully quantum-mechanical treatment, we show that there exists a thermal machine that can come arbitrarily close to extracting all the coherence as work. The machine only needs to act on individual copies of a state and can be reused. On the other hand, we show that for any thermal machine with finite resources not all the coherence of a state can be extracted as work. We provide explicit protocols extracting work from coherence when the resources of a thermal machine are bounded, a scenario potentially relevant for the thermodynamics at the nanoscale.

  18. Coherent neutrino scattering in dark matter detectors

    E-Print Network [OSTI]

    Anderson, Alexander John

    Coherent elastic neutrino-nucleus and weakly interacting massive particle-nucleus interaction signatures are expected to be quite similar. This paper discusses how a next-generation ton-scale dark matter detector could ...

  19. Managing coherence via put/get windows

    DOE Patents [OSTI]

    Blumrich, Matthias A. (Ridgefield, CT); Chen, Dong (Croton on Hudson, NY); Coteus, Paul W. (Yorktown Heights, NY); Gara, Alan G. (Mount Kisco, NY); Giampapa, Mark E. (Irvington, NY); Heidelberger, Philip (Cortlandt Manor, NY); Hoenicke, Dirk (Ossining, NY); Ohmacht, Martin (Yorktown Heights, NY)

    2011-01-11T23:59:59.000Z

    A method and apparatus for managing coherence between two processors of a two processor node of a multi-processor computer system. Generally the present invention relates to a software algorithm that simplifies and significantly speeds the management of cache coherence in a message passing parallel computer, and to hardware apparatus that assists this cache coherence algorithm. The software algorithm uses the opening and closing of put/get windows to coordinate the activated required to achieve cache coherence. The hardware apparatus may be an extension to the hardware address decode, that creates, in the physical memory address space of the node, an area of virtual memory that (a) does not actually exist, and (b) is therefore able to respond instantly to read and write requests from the processing elements.

  20. Managing coherence via put/get windows

    DOE Patents [OSTI]

    Blumrich, Matthias A. (Ridgefield, CT); Chen, Dong (Croton on Hudson, NY); Coteus, Paul W. (Yorktown Heights, NY); Gara, Alan G. (Mount Kisco, NY); Giampapa, Mark E. (Irvington, NY); Heidelberger, Philip (Cortlandt Manor, NY); Hoenicke, Dirk (Ossining, NY); Ohmacht, Martin (Yorktown Heights, NY)

    2012-02-21T23:59:59.000Z

    A method and apparatus for managing coherence between two processors of a two processor node of a multi-processor computer system. Generally the present invention relates to a software algorithm that simplifies and significantly speeds the management of cache coherence in a message passing parallel computer, and to hardware apparatus that assists this cache coherence algorithm. The software algorithm uses the opening and closing of put/get windows to coordinate the activated required to achieve cache coherence. The hardware apparatus may be an extension to the hardware address decode, that creates, in the physical memory address space of the node, an area of virtual memory that (a) does not actually exist, and (b) is therefore able to respond instantly to read and write requests from the processing elements.

  1. Insertion of coherence requests for debugging a multiprocessor

    DOE Patents [OSTI]

    Blumrich, Matthias A. (Ridgefield, CT); Salapura, Valentina (Chappaqua, NY)

    2010-02-23T23:59:59.000Z

    A method and system are disclosed to insert coherence events in a multiprocessor computer system, and to present those coherence events to the processors of the multiprocessor computer system for analysis and debugging purposes. The coherence events are inserted in the computer system by adding one or more special insert registers. By writing into the insert registers, coherence events are inserted in the multiprocessor system as if they were generated by the normal coherence protocol. Once these coherence events are processed, the processing of coherence events can continue in the normal operation mode.

  2. Extended Coherence Time with Atom-Number Squeezed Sources

    E-Print Network [OSTI]

    Wei Li; Ari K. Tuchman; Hui-Chun Chien; Mark A. Kasevich

    2006-09-02T23:59:59.000Z

    Coherence properties of Bose-Einstein condensates offer the potential for improved interferometric phase contrast. However, decoherence effects due to the mean-field interaction shorten the coherence time, thus limiting potential sensitivity. In this work, we demonstrate increased coherence times with number squeezed states in an optical lattice using the decay of Bloch oscillations to probe the coherence time. We extend coherence times by a factor of 2 over those expected with coherent state BEC interferometry. We observe quantitative agreement with theory both for the degree of initial number squeezing as well as for prolonged coherence times.

  3. Nonlinear properties of dense coherent media

    E-Print Network [OSTI]

    Mikhailov, Eugeniy Eugenievich

    2004-09-30T23:59:59.000Z

    as to style and content by: George R. Welch (Chair of Committee) Edward S. Fry (Member) M. Suhail Zubairy (Member) Paul S. Cremer (Member) Edward S. Fry (Head of Department) August 2003 Major Subject: Physics iii ABSTRACT Nonlinear Properties of Dense Coherent... Media. (August 2003) Eugeniy Eugenievich Mikhailov, B.S., Moscow State Engineering Physics Institute Chair of Advisory Committee: Dr. George R. Welch Properties of coherent media in the regime of electromagnetically induced trans- parency (EIT...

  4. A laser-wire beam-energy and beam-profile monitor at the BNL linac

    SciTech Connect (OSTI)

    Connolly, R.; Degen, C.; DeSanto, L.; Meng, W.; Michnoff, R.; Minty, M.; Nayak, S.

    2011-03-28T23:59:59.000Z

    In 2009 a beam-energy monitor was installed in the high energy beam transport (HEBT) line at the Brookhaven National Lab linac. This device measures the energies of electrons stripped from the 40mA H{sup -} beam by background gas. Electrons are stripped by the 2.0x10{sup -7}torr residual gas at a rate of {approx}1.5x10{sup -8}/cm. Since beam electrons have the same velocities as beam protons, the beam proton energy is deduced by multiplying the electron energy by m{sub p}/m{sub e}=1836. A 183.6MeV H{sup -} beam produces 100keV electrons. In 2010 we installed an optics plates containing a laser and scanning optics to add beam-profile measurement capability via photodetachment. Our 100mJ/pulse, Q-switched laser neutralizes 70% of the beam during its 10ns pulse. This paper describes the upgrades to the detector and gives profile and energy measurements.

  5. Beam dynamics studies of the 8 GeV Linac at FNAL

    SciTech Connect (OSTI)

    Ostroumov, P.N.; Mustapha, B.; /Argonne; Carneiro, J.-P.; /Fermilab

    2008-11-01T23:59:59.000Z

    The proposed 8-GeV proton driver (PD) linac at FNAL includes a front end up to {approx}420 MeV operating at 325 MHz and a high energy section at 1300 MHz. A normal conducting RFQ and short CH type resonators are being developed for the initial acceleration of the H-minus or proton beam up to 10 MeV. From 10 MeV to {approx}420 MeV, the voltage gain is provided by superconducting (SC) spoke-loaded cavities. In the high-energy section, the acceleration will be provided by the International Linear Collider (ILC)-style SC elliptical cell cavities. To employ existing, readily available klystrons, an RF power fan out from high-power klystrons to multiple cavities is being developed. The beam dynamics simulation code TRACK, available in both serial and parallel versions, has been updated to include all known H-minus stripping mechanisms to predict the exact location of beam losses. An iterative simulation procedure is being developed to interact with a transient beam loading model taking into account RF feedback and feedforward systems.

  6. Control of coherence resonance in semiconductor superlattices

    E-Print Network [OSTI]

    Johanne Hizanidis; Eckehard Schoell

    2008-09-01T23:59:59.000Z

    We study the effect of time-delayed feedback control and Gaussian white noise on the spatio-temporal charge dynamics in a semiconductor superlattice. The system is prepared in a regime where the deterministic dynamics is close to a global bifurcation, namely a saddle-node bifurcation on a limit cycle ({\\it SNIPER}). In the absence of control, noise can induce electron charge front motion through the entire device, and coherence resonance is observed. We show that with appropriate selection of the time-delayed feedback parameters the effect of coherence resonance can either be enhanced or destroyed, and the coherence of stochastic domain motion at low noise intensity is dramatically increased. Additionally, the purely delay-induced dynamics in the system is investigated, and a homoclinic bifurcation of a limit cycle is found.

  7. Color coherence in W + jet events

    SciTech Connect (OSTI)

    Abbott, B.; D0 Collaboration

    1997-11-01T23:59:59.000Z

    We report on preliminary studies of color coherence effects in p{anti p} collisions, based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron collider, at a center of mass energy {radical}s = 1.8 TeV. Color interference effects are studied by examining particle distribution patterns in W + Jet events. The data are compared to Monte Carlo simulations with different color coherence implementations and to a recent analytic Modified-Leading-Log perturbative calculation based on the Local Parton-Hadron Duality hypothesis. Soft particle radiation is enhanced in the event plane relative to the transverse plane, in agreement with calculations in which the effects of color coherence are fully included.

  8. Store-operate-coherence-on-value

    DOE Patents [OSTI]

    Chen, Dong; Heidelberger, Philip; Kumar, Sameer; Ohmacht, Martin; Steinmacher-Burow, Burkhard

    2014-11-18T23:59:59.000Z

    A system, method and computer program product for performing various store-operate instructions in a parallel computing environment that includes a plurality of processors and at least one cache memory device. A queue in the system receives, from a processor, a store-operate instruction that specifies under which condition a cache coherence operation is to be invoked. A hardware unit in the system runs the received store-operate instruction. The hardware unit evaluates whether a result of the running the received store-operate instruction satisfies the condition. The hardware unit invokes a cache coherence operation on a cache memory address associated with the received store-operate instruction if the result satisfies the condition. Otherwise, the hardware unit does not invoke the cache coherence operation on the cache memory device.

  9. Quantum Coherence and Closed Timelike Curves

    E-Print Network [OSTI]

    S. W. Hawking

    1995-02-08T23:59:59.000Z

    Various calculations of the $S$ matrix have shown that it seems to be non unitary for interacting fields when there are closed timelike curves. It is argued that this is because there is loss of quantum coherence caused by the fact that part of the quantum state circulates on the closed timelike curves and is not measured at infinity. A prescription is given for calculating the superscattering matrix $\\$ $ on space times whose parameters can be analytically continued to obtain a Euclidean metric. It is illustrated by a discussion of a spacetime in with two disks in flat space are identified. If the disks have an imaginary time separation, this corresponds to a heat bath. An external field interacting with the heat bath will lose quantum coherence. One can then analytically continue to an almost real separation of the disks. This will give closed timelike curves but one will still get loss of quantum coherence.

  10. Global coherence of dust density waves

    SciTech Connect (OSTI)

    Killer, Carsten; Melzer, André [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)

    2014-06-15T23:59:59.000Z

    The coherence of self-excited three-dimensional dust density waves has been experimentally investigated by comparing global and local wave properties. For that purpose, three-dimensional dust clouds have been confined in a radio frequency plasma with thermophoretic levitation. Global wave properties have been measured from the line-of-sight integrated dust density obtained from homogenous light extinction measurements. Local wave properties have been obtained from thin, two-dimensional illuminated laser slices of the cloud. By correlating the simultaneous global and local wave properties, the spatial coherence of the waves has been determined. We find that linear waves with small amplitudes tend to be fragmented, featuring an incoherent wave field. Strongly non-linear waves with large amplitudes, however, feature a strong spatial coherence throughout the dust cloud, indicating a high level of synchronization.

  11. Exciton coherence lifetimes from electronic structure

    E-Print Network [OSTI]

    Parkhill, John; Aspuru-Guzik, Alan

    2011-01-01T23:59:59.000Z

    We model the coherent energy transfer of an electronic excitation within covalently linked aromatic homodimers from first-principles, to answer whether the usual models of the bath calculated via detailed electronic structure calculations can reproduce the key dynamics. For these systems the timescales of coherent transport are experimentally known from time-dependent polarization anisotropy measurements, and so we can directly assess the whether current techniques might be predictive for this phenomenon. Two choices of electronic basis states are investigated, and their relative merits discussed regarding the predictions of the perturbative model. The coupling of the electronic degrees of freedom to the nuclear degrees of freedom is calculated rather than assumed, and the fluorescence anisotropy decay is directly reproduced. Surprisingly we find that although TDDFT absolute energies are routinely in error by orders of magnitude more than the coupling energy, the coherent transport properties of these dimers ...

  12. SU-E-T-48: Automated Quality Assurance for XML Controlled Linacs

    SciTech Connect (OSTI)

    Valdes, G; Morin, O; Pouliot, J; Chuang, C [UC San Francisco, San Francisco, CA (United States)

    2014-06-01T23:59:59.000Z

    Purpose: To automate routine imaging QA procedures so that complying with TG 142 and TG 179 can be efficient and reliable. Methods: Two QA tests for a True Beam Linac were automatized. A Winston Lutz test as described by Lutz et al{sup 1} using the Winston Lutz test kit from BrainLab, Germany and a CBCT Image Quality test as described in TG 179 using the EMMA phantom, Siemens Medical Physics, Germany were performed in our True Beam. For each QA procedure tested, a 3 step paradigm was used. First, the data was automatically acquired using True Beam Developer Mode and XML scripting. Second, the data acquired in the first step was automatically processed using in-home grown Matlab GUIs. Third, Machine Learning algorithms were used to automatically classify the processed data and reports generated. Results: The Winston Luzt test could be performed by an experienced medical physicist in 29.0 ± 8.0 min. The same test, if automated using our paradigm, could be performed in 3.0 ± 0.1 min. In the same lieu, time could be substantially saved for image quality tests. In this case, the amount of time saved will depend on the phantoms used and the initial localization method. Additionally, machine learning algorithms could automatically identify the roots of the problems if any and possibly help reduce machine down time. Conclusion: Modern linear accelerators are equipped with advanced 2D and 3D imaging that are used for patient alignment substantially improving IGRT protocols. However, this extra complexity exponentially increases the number of QA tests needed. Using the new paradigm described above, not only bare minimum but best practice QA programs could be implemented with the same manpower. This work is supported by Varian, Palo Alto, CA.

  13. Cryogenic system for the Energy Recovery Linac and vertical test facility at BNL

    SciTech Connect (OSTI)

    Than, R.; Soria, V.; Lederle, D.; Orfin, P.; Porqueddu, R.; Talty, P.; Zhang, Y.; Tallerico, T.; Masi, L.

    2011-03-28T23:59:59.000Z

    A small cryogenic system and warm helium vacuum pumping system provides cooling to either the Energy Recovery Linac's (ERL) cryomodules that consist of a 5-cell cavity and an SRF gun or a large Vertical Test Dewar (VTD) at any given time. The cryogenic system consists of a model 1660S PSI piston plant, a 3800 liter storage dewar, subcooler, a wet expander, a 50 g/s main helium compressor, and a 170 m{sup 3} storage tank. A system description and operating plan of the cryogenic plant and cryomodules is given. The cryogenic system for ERL and the Vertical Test Dewar has a plant that can produce the equivalent of 300W at 4.5K with the addition of a wet expander 350 W at 4.5K. Along with this system, a sub-atmospheric, warm compression system provides pumping to produce 2K at the ERL cryomodules or the Vertical Test Dewar. The cryogenic system for ERL and the Vertical Test Dewar makes use of existing equipment for putting a system together. It can supply either the ERL side or the Vertical Test Dewar side, but not both at the same time. Double valve isolation on the liquid helium supply line allows one side to be warmed to room temperature and worked on while the other side is being held at operating temperature. The cryogenic system maintain the end loads from 4.4K to 2K or colder depending on capacity. Liquid helium storage dewar capacity allows ERL or the VTD to operate above the plant's capacity when required and ERL cryomodules ballast reservoirs and VTD reservoir allows the end loads to operate on full vacuum pump capacity when required.

  14. Coherent coupling of optical gain elements

    SciTech Connect (OSTI)

    Ury, I.; Yariv, A

    1989-05-23T23:59:59.000Z

    A coherent light source is described comprising: a non-linear photorefractive medium; a laser for illuminating the photorefractive medium; a mirror on the opposite side of the photorefractive medium from the laser and aligned for retroreflecting light back toward the laser; and optical gain elements. Each optical gain element has its optical axis aligned with the photo-refractive medium, each optical gain element having a reflective end remote from the photorefractive medium, the laser and optical gain elements being sufficiently aligned that laser light scattered from the photorefractive medium illuminates all of the optical gain elements for amplification and producing a coherent output beam.

  15. Low-temperature thermodynamics with quantum coherence

    E-Print Network [OSTI]

    Varun Narasimhachar; Gilad Gour

    2014-10-02T23:59:59.000Z

    We find a new characterization of low-temperature processes, which we call "cooling processes", incorporating quantum coherence in the model of thermodynamics for the first time. We derive necessary and sufficient conditions for the feasibility of state transitions under cooling processes. We also rigorously confirm the intuitive robustness of coherence against low-temperature thermal noise. Additionally, we develop the low-temperature "Gibbs-preserving" model, and by comparing our results on the two models, we argue that the latter is a poor approximation to physical processes.

  16. Use of off-axis injection as an alternative to geometrically merging beams in an energy-recovering linac

    DOE Patents [OSTI]

    Douglas, David R. (York County, VA)

    2012-01-10T23:59:59.000Z

    A method of using off-axis particle beam injection in energy-recovering linear accelerators that increases operational efficiency while eliminating the need to merge the high energy re-circulating beam with an injected low energy beam. In this arrangement, the high energy re-circulating beam and the low energy beam are manipulated such that they are within a predetermined distance from one another and then the two immerged beams are injected into the linac and propagated through the system. The configuration permits injection without geometric beam merging as well as decelerated beam extraction without the use of typical beamline elements.

  17. Spatial coherence resonance on diffusive and small-world networks of Hodgkin-Huxley neurons

    E-Print Network [OSTI]

    Xiaojuan Sun; Matjaz Perc; Qishao Lu; Jürgen Kurths

    2008-03-01T23:59:59.000Z

    Spatial coherence resonance in a spatially extended system that is locally modeled by Hodgkin-Huxley (HH) neurons is studied in this paper. We focus on the ability of additive temporally and spatially uncorrelated Gaussian noise to extract a particular spatial frequency of excitatory waves in the medium, whereby examining also the impact of diffusive and small-world network topology determining the interactions amongst coupled HH neurons. We show that there exists an intermediate noise intensity that is able to extract a characteristic spatial frequency of the system in a resonant manner provided the latter is diffusively coupled, thus indicating the existence of spatial coherence resonance. However, as the diffusive topology of the medium is relaxed via the introduction of shortcut links introducing small-world properties amongst coupled HH neurons, the ability of additive Gaussian noise to evoke ordered excitatory waves deteriorates rather spectacularly, leading to the decoherence of the spatial dynamics and with it related absence of spatial coherence resonance. In particular, already a minute fraction of shortcut links suffices to substantially disrupt coherent pattern formation in the examined system.

  18. Quasi Light Fields: A Model of Coherent Image Formation

    E-Print Network [OSTI]

    Accardi, Anthony J.

    We develop a model of coherent image formation that strikes a balance between the simplicity of the light field and the comprehensive predictive power of Maxwell's equations, by extending the light field to coherent radiation.

  19. CIRCE: A dedicated storage ring for coherent THz synchrotron radiation

    E-Print Network [OSTI]

    2003-01-01T23:59:59.000Z

    coherent synchrotron radiation detected at BESSY II",BESSY[14]. Therefore the model is quite robust to different synchrotrons

  20. Coherent Radiation Effects in the LCLS Undulator

    SciTech Connect (OSTI)

    Reiche, S.; /UCLA; Huang, Z.; /SLAC

    2010-12-14T23:59:59.000Z

    For X-ray Free-Electron Lasers such as LCLS and TESLA FEL, a change in the electron energy while amplifying the FEL radiation can shift the resonance condition out of the bandwidth of the FEL. The largest sources of energy loss is the emission of incoherent undulator radiation. Because the loss per electron depends only on the undulator parameters and the beam energy, which are fixed for a given resonant wavelength, the average energy loss can be compensated for by a fixed taper of the undulator. Coherent radiation has a strong enhancement proportional to the number of electrons in the bunch for frequencies comparable to or longer than the bunch dimension. If the emitted coherent energy becomes comparable to that of the incoherent emission, it has to be included in the taper as well. However, the coherent loss depends on the bunch charge and the applied compression scheme and a change of these parameters would require a change of the taper. This imposes a limitation on the practical operation of Free-Electron Lasers, where the taper can only be adjusted manually. In this presentation we analyze the coherent emission of undulator radiation and transition undulator radiation for LCLS, and estimate whether the resulting energy losses are significant for the operation of LCLS.

  1. Coherent multilayer crystals and method of making

    DOE Patents [OSTI]

    Schuller, I.K.; Falco, C.M.

    1980-10-30T23:59:59.000Z

    A new material is described consisting of a coherent multilayer crystal of two or more elements where each layer is composed of a single element. Each layer may vary in thickness from about 2 A to 2500 A. The multilayer crystals are prepared by sputter deposition under conditions which slow the sputtered atoms to near substrate temperatures before they contact the substrate.

  2. Exciton coherence lifetimes from electronic structure

    E-Print Network [OSTI]

    John Parkhill; David Tempel; Alan Aspuru-Guzik

    2011-12-13T23:59:59.000Z

    We model the coherent energy transfer of an electronic excitation within covalently linked aromatic homodimers from first-principles, to answer whether the usual models of the bath calculated via detailed electronic structure calculations can reproduce the key dynamics. For these systems the timescales of coherent transport are experimentally known from time-dependent polarization anisotropy measurements, and so we can directly assess the whether current techniques might be predictive for this phenomenon. Two choices of electronic basis states are investigated, and their relative merits discussed regarding the predictions of the perturbative model. The coupling of the electronic degrees of freedom to the nuclear degrees of freedom is calculated rather than assumed, and the fluorescence anisotropy decay is directly reproduced. Surprisingly we find that although TDDFT absolute energies are routinely in error by orders of magnitude more than the coupling energy, the coherent transport properties of these dimers can be semi-quantitatively reproduced from first-principles. The directions which must be pursued to yield predictive and reliable prediction of coherent transport are suggested.

  3. PHASE COHERENCE PHENOMENA IN DISORDERED SUPERCONDUCTORS

    E-Print Network [OSTI]

    Simons, Ben

    PHASE COHERENCE PHENOMENA IN DISORDERED SUPERCONDUCTORS A. LAMACRAFT AND B. D. SIMONS Cavendish on the quasi­particle properties of disordered superconductors. Again, attempts to develop a consistent theory has been formulated. Yet, a complete description of the phenomenology of the disordered superconductor

  4. Coherent states in the fermionic Fock space

    E-Print Network [OSTI]

    Robert Oeckl

    2015-01-09T23:59:59.000Z

    We construct the coherent states in the sense of Gilmore and Perelomov for the fermionic Fock space. Our treatment is from the outset adapted to the infinite-dimensional case. The fermionic Fock space becomes in this way a reproducing kernel Hilbert space of continuous holomorphic functions.

  5. Transverse Coherence of a VUV Free Electron Laser

    E-Print Network [OSTI]

    Transverse Coherence of a VUV Free Electron Laser Dissertation zur Erlangung des Doktorgrades des The transverse coherence is of paramount importance for many applications of a free electron laser (FEL). In this thesis, the first direct measurement of the transverse coherence of a free electron laser at vacuum

  6. Quasi light fields: extending the light field to coherent radiation

    E-Print Network [OSTI]

    Wornell, Gregory W.

    Quasi light fields: extending the light field to coherent radiation Anthony Accardi1,2 and Gregory light field, and for coherent radiation using electromagnetic field theory. We present a model of coherent image formation that strikes a balance between the utility of the light field

  7. Quantum coherence in semiconductor nanostructures for improved lasers and detectors.

    SciTech Connect (OSTI)

    Chow, Weng Wah Dr. (; .); Lyo, Sungkwun Kenneth; Cederberg, Jeffrey George; Modine, Normand Arthur; Biefeld, Robert Malcolm

    2006-02-01T23:59:59.000Z

    The potential for implementing quantum coherence in semiconductor self-assembled quantum dots has been investigated theoretically and experimentally. Theoretical modeling suggests that coherent dynamics should be possible in self-assembled quantum dots. Our experimental efforts have optimized InGaAs and InAs self-assembled quantum dots on GaAs for demonstrating coherent phenomena. Optical investigations have indicated the appropriate geometries for observing quantum coherence and the type of experiments for observing quantum coherence have been outlined. The optical investigation targeted electromagnetically induced transparency (EIT) in order to demonstrate an all optical delay line.

  8. Tabletop Nanometer Extreme Ultraviolet Imaging in an Extended Reflection Mode using Coherent Fresnel Ptychography

    E-Print Network [OSTI]

    Seaberg, Matthew D; Gardner, Dennis F; Shanblatt, Elisabeth R; Murnane, Margaret M; Kapteyn, Henry C; Adams, Daniel E

    2013-01-01T23:59:59.000Z

    We demonstrate high resolution extreme ultraviolet (EUV) coherent diffractive imaging in the most general reflection geometry by combining ptychography with tilted plane correction. This method makes it possible to image extended surfaces at any angle of incidence. Refocused light from a tabletop coherent high harmonic light source at 29 nm illuminates a nanopatterned surface at 45 degree angle of incidence. The reconstructed image contains quantitative amplitude and phase (in this case pattern height) information, comparing favorably with both scanning electron microscope and atomic force microscopy images. In the future, this approach will enable imaging of complex surfaces and nanostructures with sub-10 nm-spatial resolution and fs-temporal resolution, which will impact a broad range of nanoscience and nanotechnology including for direct application in actinic inspection in support of EUV lithography.

  9. in2p3-00356643,version1-28Jan2009 Author manuscript, published in "XXIV Linear Accelerator Conference "LINAC'08", Victoria : Canada (2008)"

    E-Print Network [OSTI]

    Boyer, Edmond

    2008-01-01T23:59:59.000Z

    Conference "LINAC'08", Victoria : Canada (2008)" #12;LAL/RT 08-22 October 2008 BEAM DYNAMICS SIMULATIONS dynamic simulations using the PARMELA code to study the performances of the alphaX photo, the surface electrical field is reduced by a factor 2 with respect to the more usual cylindrical shape. So one

  10. BEAM DYNAMICS STUDIES IN SPIRAL 2 LINAC R. Duperrier, D. Uriot, CEA Saclay, 91191 Gif sur Yvette; N. Pichoff , CEA Bruyres le Chtel, BP

    E-Print Network [OSTI]

    Boyer, Edmond

    of an injector (two ECR sources + a Radio Frequency Quadrupole) followed by a superconducting section based) and a superconducting linac with independent resonators (QWRs and/or HWRs). The accelerating optimisation has to be performed for ions with q/A=1/3 (optimum for the superconducting part). The input energy is 20 A

  11. Coherent water transport across the South Atlantic

    E-Print Network [OSTI]

    Wang, Y; Beron-Vera, F J

    2015-01-01T23:59:59.000Z

    The role of mesoscale eddies in transporting Agulhas leakage is investigated using a recent technique from nonlinear dynamical systems theory applied on geostrophic currents inferred from the over two-decade-long satellite altimetry record. Eddies are found to acquire material coherence away from the Agulhas retroflection, near the Walvis Ridge in the South Atlantic. Yearly, 1 to 4 coherent material eddies are detected with diameters ranging from 40 to 280 km. A total of 23 eddy cores of about 50 km in diameter and with at least 30% of their contents traceable into the Indian Ocean were found to travel across the subtropical gyre with minor filamentation. No more than 5\\% of such cores pour their contents on the North Brazil Current. While ability of eddies to carry Agulhas leakage northwestward across the South Atlantic is supported by our analysis, this is more restricted than suggested by earlier ring transport assessments.

  12. COHERENT LASER VISION SYSTEM (CLVS) OPTION PHASE

    SciTech Connect (OSTI)

    Robert Clark

    1999-11-18T23:59:59.000Z

    The purpose of this research project was to develop a prototype fiber-optic based Coherent Laser Vision System (CLVS) suitable for DOE's EM Robotic program. The system provides three-dimensional (3D) vision for monitoring situations in which it is necessary to update the dimensional spatial data on the order of once per second. The system has total immunity to ambient lighting conditions.

  13. Coherent states in the quantum multiverse

    E-Print Network [OSTI]

    S. Robles-Perez; Y. Hassouni; P. F. Gonzalez-Diaz

    2009-11-24T23:59:59.000Z

    In this paper, we study the role of coherent states in the realm of quantum cosmology, both in a second-quantized single universe and in a third-quantized quantum multiverse. In particular, most emphasis will be paid to the quantum description of multiverses made up of accelerated universes. We have shown that the quantum states involved at a quantum mechanical multiverse whose single universes are accelerated are given by squeezed states having no classical analogs.

  14. Geometric phases for generalized squeezed coherent states

    E-Print Network [OSTI]

    S. Seshadri; S. Lakshmibala; V. Balakrishnan

    1999-05-31T23:59:59.000Z

    A simple technique is used to obtain a general formula for the Berry phase (and the corresponding Hannay angle) for an arbitrary Hamiltonian with an equally-spaced spectrum and appropriate ladder operators connecting the eigenstates. The formalism is first applied to a general deformation of the oscillator involving both squeezing and displacement. Earlier results are shown to emerge as special cases. The analysis is then extended to multiphoton squeezed coherent states and the corresponding anholonomies deduced.

  15. Emergence of non-zonal coherent structures

    E-Print Network [OSTI]

    Bakas, Nikolaos A

    2015-01-01T23:59:59.000Z

    Planetary turbulence is observed to self-organize into large-scale structures such as zonal jets and coherent vortices. One of the simplest models that retains the relevant dynamics of turbulent self-organization is a barotropic flow in a beta-plane channel with turbulence sustained by random stirring. Non-linear integrations of this model show that as the energy input rate of the forcing is increased, the homogeneity of the flow is first broken by the emergence of non-zonal, coherent, westward propagating structures and at larger energy input rates by the emergence of zonal jets. The emergence of both non-zonal coherent structures and zonal jets is studied using a statistical theory, Stochastic Structural Stability Theory (S3T). S3T directly models a second-order approximation to the statistical mean turbulent state and allows the identification of statistical turbulent equilibria and study of their stability. Using S3T, the bifurcation properties of the homogeneous state in barotropic beta-plane turbulence ...

  16. D-dimensional Smorodinsky-Winternitz potential: Coherent state approach

    SciTech Connect (OSTI)

    Uenal, Nuri, E-mail: nuriunal@akdeniz.edu.tr [Akdeniz University, Department of Physics (Turkey)] [Akdeniz University, Department of Physics (Turkey)

    2013-10-15T23:59:59.000Z

    In this study, we construct the coherent states for a particle in the D-dimensional maximally superintegrable Smorodinsky-Winternitz potential. We, first, map the system into 2D harmonic oscillators, second, construct the coherent states of them by evaluating the transition amplitudes. Third, in the Cartesian and the hyperspherical coordinates, we find the coherent states and the stationary states of the original sytem by reduction.

  17. Coherent Vibrational Dynamics and High-Resolution Nonlinear Spectrosco...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Vibrational Dynamics and High-Resolution Nonlinear Spectroscopy: A Comparison with the AirDMSO Liquid Interface. Coherent Vibrational Dynamics and High-Resolution Nonlinear...

  18. Coherent Electron Cooling: JLab Effort Helps to Cool Particle...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    labmanager.com?articles.viewarticleNo7392titleCoherent-Electron-Cooling--Combining-Methods-to-Cool-Parti... Submitted: Friday, April 13...

  19. The role of pump coherence in two-photon interferometry

    E-Print Network [OSTI]

    J. Liang; S. M. Hendrickson; T. B. Pittman

    2010-12-20T23:59:59.000Z

    We use a parametric down-conversion source pumped by a short coherence-length continuous-wave (CW) diode laser to perform two-photon interferometry in an intermediate regime between the more familiar Franson-type experiments with a long coherence-length pump laser, and the short pulsed pump "time-bin" experiments pioneered by Gisin's group. The use of a time-bin-like Mach-Zehnder interferometer in the CW pumping beam induces coherence between certain two-photon amplitudes, while the CW nature of the experiment prevents the elimination of remaining incoherent ones. The experimental results highlight the role of pump coherence in two-photon interferometry.

  20. Minimally invasive diagnostic imaging using high resolution Optical Coherence Tomography

    E-Print Network [OSTI]

    Herz, Paul Richard, 1972-

    2004-01-01T23:59:59.000Z

    Advances in medical imaging have given researchers unprecedented capabilities to visualize, characterize and understand biological systems. Optical Coherence Tomography (OCT) is a high speed, high resolution imaging technique ...

  1. Coherent Carbon Cryogel-Ammonia Borane Nanocomposites for Improved...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Carbon Cryogel-Ammonia Borane Nanocomposites for Improved Hydrogen Storage. Coherent Carbon Cryogel-Ammonia Borane Nanocomposites for Improved Hydrogen Storage. Abstract: Ammonia...

  2. Generation of Coherent X-Ray Radiation Through Modulation Compression

    E-Print Network [OSTI]

    Qiang, Ji

    2011-01-01T23:59:59.000Z

    ultra-short coherent X-ray radiation by controlling the fraction of the beam that can be properly unchirped using a few-cycle laser

  3. Ultrabroadband coherence-domain imaging using parametric downconversion and

    E-Print Network [OSTI]

    Teich, Malvin C.

    Ultrabroadband coherence-domain imaging using parametric downconversion and superconducting single lithium tantalate (chirped-PPSLT) structure, in conjunction with a niobium nitride superconducting single

  4. On solving multistage stochastic programs with coherent risk ...

    E-Print Network [OSTI]

    A. B. Philpott

    2012-08-13T23:59:59.000Z

    Aug 13, 2012 ... Abstract: We consider a class of multistage stochastic linear programs in which at each stage a coherent risk measure of future costs is to be ...

  5. The coordinate coherent states approach revisited

    SciTech Connect (OSTI)

    Miao, Yan-Gang, E-mail: miaoyg@nankai.edu.cn; Zhang, Shao-Jun, E-mail: sjzhang@mail.nankai.edu.cn

    2013-02-15T23:59:59.000Z

    We revisit the coordinate coherent states approach through two different quantization procedures in the quantum field theory on the noncommutative Minkowski plane. The first procedure, which is based on the normal commutation relation between an annihilation and creation operators, deduces that a point mass can be described by a Gaussian function instead of the usual Dirac delta function. However, we argue this specific quantization by adopting the canonical one (based on the canonical commutation relation between a field and its conjugate momentum) and show that a point mass should still be described by the Dirac delta function, which implies that the concept of point particles is still valid when we deal with the noncommutativity by following the coordinate coherent states approach. In order to investigate the dependence on quantization procedures, we apply the two quantization procedures to the Unruh effect and Hawking radiation and find that they give rise to significantly different results. Under the first quantization procedure, the Unruh temperature and Unruh spectrum are not deformed by noncommutativity, but the Hawking temperature is deformed by noncommutativity while the radiation specturm is untack. However, under the second quantization procedure, the Unruh temperature and Hawking temperature are untack but the both spectra are modified by an effective greybody (deformed) factor. - Highlights: Black-Right-Pointing-Pointer Suggest a canonical quantization in the coordinate coherent states approach. Black-Right-Pointing-Pointer Prove the validity of the concept of point particles. Black-Right-Pointing-Pointer Apply the canonical quantization to the Unruh effect and Hawking radiation. Black-Right-Pointing-Pointer Find no deformations in the Unruh temperature and Hawking temperature. Black-Right-Pointing-Pointer Provide the modified spectra of the Unruh effect and Hawking radiation.

  6. Impact of Pump Quality on the Performances of Fibre Optical Parametric Amplifiers

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Impact of Pump Quality on the Performances of Fibre Optical Parametric Amplifiers Thibaut to the pump wave characteristics ranging from the monochromatic coherent case to the incoherent one. I- stood. In particular, the impact of pump incoherence, or, more precisely, of the field amplitude

  7. Coherent Transition Radiation in Askaryan radio detectors

    E-Print Network [OSTI]

    de Vries, Krijn D; van Eijndhoven, Nick; Meures, Thomas; O'Murchadha, Aongus; Scholten, Olaf

    2015-01-01T23:59:59.000Z

    We discuss the coherent transition radiation emitted by a macroscopic bunch of particles with a net charge traversing the boundary of two different media. The obtained expression is compared to the emission from a relativistically moving steady charge, as well the emission from a time-varying charge or current. As a first application, we discuss the transition radiation from high-energy cosmic-ray induced air showers hitting Earth's surface before the cascade has died out in the atmosphere. The induced emission gives rise to a radio signal which should be detectable in the currently operating Askaryan radio detectors built to search for the GZK neutrino flux.

  8. Optical coherence tomography guided dental drill

    DOE Patents [OSTI]

    DaSilva, Luiz B. (Danville, CA); Colston, Jr., Bill W. (Livermore, CA); James, Dale L. (Tracy, CA)

    2002-01-01T23:59:59.000Z

    A dental drill that has one or multiple single mode fibers that can be used to image in the vicinity of the drill tip. It is valuable to image below the surface being drilled to minimize damage to vital or normal tissue. Identifying the boundary between decayed and normal enamel (or dentine) would reduce the removal of viable tissue, and identifying the nerve before getting too close with the drill could prevent nerve damage. By surrounding a drill with several optical fibers that can be used by an optical coherence domain reflectometry (OCDR) to image several millimeters ahead of the ablation surface will lead to a new and improved dental treatment device.

  9. Improved superconducting qubit coherence using titanium nitride

    E-Print Network [OSTI]

    J. Chang; M. R. Vissers; A. D. Corcoles; M. Sandberg; J. Gao; David W. Abraham; Jerry M. Chow; Jay M. Gambetta; M. B. Rothwell; G. A. Keefe; Matthias Steffen; D. P. Pappas

    2013-03-17T23:59:59.000Z

    We demonstrate enhanced relaxation and dephasing times of transmon qubits, up to ~ 60 \\mu s by fabricating the interdigitated shunting capacitors using titanium nitride (TiN). Compared to lift-off aluminum deposited simultaneously with the Josephson junction, this represents as much as a six-fold improvement and provides evidence that previous planar transmon coherence times are limited by surface losses from two-level system (TLS) defects residing at or near interfaces. Concurrently, we observe an anomalous temperature dependent frequency shift of TiN resonators which is inconsistent with the predicted TLS model.

  10. COHERENT STRUCTURES IN PLASMA TURBULENCE: PERSISTENCE, INTERMITTENCY,

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i t z C o . C l a r k CCLEAN9AugustCNSSPracticesCOHERENT

  11. NDCX-II, an Induction Linac for HEDP and IFE Research

    SciTech Connect (OSTI)

    Kwan, J.W.; Arbelaez, D.; Bieniosek, F.M.; Faltens, A.; Friedman, A.; Galvin, J.; Greenway, W.; Gilson, E. P.; Grote, D. P.; Jung, J.Y.; Lee, E.P.; Leitner, M.; Lidia, S.M.; Logan, B.G.; Lund, S. M.; Reginato, L.L.; Roy, P.K.; Seidl, P.A.; Sharp, W. M.; Takakuwa, J.; Waldron, W.L.

    2011-04-20T23:59:59.000Z

    The Heavy Ion Fusion Science Virtual National Laboratory in the USA is constructing a new Neutralized Drift Compression eXperiment (NDCX-II) at LBNL. This facility is being developed for high energy density physics and inertial fusion energy research. The 12 m long induction linac in NDCX-II will produce a Li{sup +} beam pulse, at energies of 1.2-3 MeV, to heat target material to the warm dense matter regime ({approx} 1 eV). By making use of special acceleration voltage waveforms, 2.5T solenoid focusing, and neutralized drift compression, 20 - 50 nC of beam charge from the ion source will be compressed longitudinally and radially to achieve a subnanosecond pulse length and mm-scale target spot size. The original Neutralized Drift Compression Experiment (NDCX-I) has successfully demonstrated simultaneous radial and longitudinal compression by imparting a velocity ramp to the ion beam, which then drifts in a neutralizing plasma to and through the final focussing solenoid and onto the target. At higher kinetic energy and current, NDCX-II will offer more than 100 times the peak energy fluence on target of NDCX-I. NDCX-II makes use of many parts from the decommissioned Advanced Test Accelerator (ATA) at LLNL. It includes 27 lattice periods between the injector and the neutralized drift compression section (Figure 1). There are 12 energized induction cells, 9 inactive cells which provide drift space, and 6 diagnostic cells which provide beam diagnostics and pumping. Custom pulsed power systems generate ramped waveforms for the first 7 induction cells, so as to quickly compress the beam from 600 ns at the injector down to 70 ns. After this compression, the high voltages of the ATA Blumleins are then used to rapidly add energy to the beam. The Blumleins were designed to match the ferrite core volt-seconds with pulses up to 250 kV and a fixed FWHM of 70 ns. The machine is limited to a pulse repetition rate of once every 20 seconds due to cooling requirements. The NDCX-II beam is highly space-charge dominated. The 1-D ASP code was used to synthesize high voltage waveform for acceleration, while the 3-D Warp particle-in-cell code was used for detailed design of the lattice. The Li{sup +} ion was chosen because its Bragg Peak energy (at {approx} 2 MeV) coincides with the NDCX-II beam energy. The 130 keV injector will have a 10.9 cm diameter ion source. Testing of small (0.64 cm diameter) lithium doped alumino-silicate ion sources has demonstrated the current density ({approx} 1 mA/cm{sup 2}) used in the design, with acceptable lifetime. A 7.6 cm diameter source has been successfully produced to verify that the coating method can be applied to such a large emitting area. The ion source will operate at {approx} 1275 C; thus a significant effort was made in the design to manage the 4 kW heating power and the associated cooling requirements. In modifying the ATA induction cells for NDCX-II, the low-field DC solenoids were replaced with 2.5 T pulsed solenoids. The beam pipe diameter was decreased in order to reduce the axial extent of the solenoid fringe fields and to make room for water cooling. In addition, an outer copper cylinder (water-cooled) was used to exclude the solenoid magnetic flux from the ferrite cores. Precise alignment is essential because the beam has a large energy spread due to the rapid pulse compression, such that misalignments lead to corkscrew deformation of the beam and reduced intensity at focus. A novel pulsed-wire measurement method is used to align the pulsed solenoid magnets. Alignment accuracy has been demonstrated to within 100 {micro}m of the induction cell axis. The neutralized drift compression region after the last induction cell is approximately 1.2 m long and includes ferroelectric plasma sources (FEPS) fabricated by PPPL similar to those successfully operating in NDCX-I. The 8-T final focus pulsed solenoid, filtered cathodic arc plasma sources (FCAPS), and target chamber from NDCX-I are to be relocated to NDCX-II. The NDCX-II project started in July 2009 and is expected to complete in fall of 2011.

  12. Catheter guided by optical coherence domain reflectometry

    DOE Patents [OSTI]

    Everett, Matthew (Pleasanton, CA); Colston, Billy W. (Livermore, CA); Da Silva, Luiz B. (Danville, CA); Matthews, Dennis (Moss Beach, CA)

    2002-01-01T23:59:59.000Z

    A guidance and viewing system based on multiplexed optical coherence domain reflectometry is incorporated into a catheter, endoscope, or other medical device to measure the location, thickness, and structure of the arterial walls or other intra-cavity regions at discrete points on the medical device during minimally invasive medical procedures. The information will be used both to guide the device through the body and to evaluate the tissue through which the device is being passed. Multiple optical fibers are situated along the circumference of the device. Light from the distal end of each fiber is directed onto the interior cavity walls via small diameter optics (such as gradient index lenses and mirrored corner cubes). Both forward viewing and side viewing fibers can be included. The light reflected or scattered from the cavity walls is then collected by the fibers and multiplexed at the proximal end to the sample arm of an optical low coherence reflectometer. The system may also be implemented in a nonmedical inspection device.

  13. Quantum process tomography with coherent states

    E-Print Network [OSTI]

    Saleh Rahimi-Keshari; Artur Scherer; Ady Mann; Ali T. Rezakhani; A. I. Lvovsky; Barry C. Sanders

    2010-09-17T23:59:59.000Z

    We develop an enhanced technique for characterizing quantum optical processes based on probing unknown quantum processes only with coherent states. Our method substantially improves the original proposal [M. Lobino et al., Science 322, 563 (2008)], which uses a filtered Glauber-Sudarshan decomposition to determine the effect of the process on an arbitrary state. We introduce a new relation between the action of a general quantum process on coherent state inputs and its action on an arbitrary quantum state. This relation eliminates the need to invoke the Glauber-Sudarshan representation for states; hence it dramatically simplifies the task of process identification and removes a potential source of error. The new relation also enables straightforward extensions of the method to multi-mode and non-trace-preserving processes. We illustrate our formalism with several examples, in which we derive analytic representations of several fundamental quantum optical processes in the Fock basis. In particular, we introduce photon-number cutoff as a reasonable physical resource limitation and address resource vs accuracy trade-off in practical applications. We show that the accuracy of process estimation scales inversely with the square root of photon-number cutoff.

  14. Robust time-varying multivariate coherence estimation: Application to electroencephalogram recordings during general anesthesia

    E-Print Network [OSTI]

    Brown, Emery N.

    Coherence analysis characterizes frequency-dependent covariance between signals, and is useful for multivariate oscillatory data often encountered in neuroscience. The global coherence provides a summary of coherent behavior ...

  15. Progress on the Construction of the 100 MeV / 100 kW Electron Linac for the NSC KIPT Neutron Source

    E-Print Network [OSTI]

    Yun-Long, Chi; Guo-Xi, Pei; Shu-Hong, Wang; Jian-She, Cao; Mi, Hou; Wei-Bin, Liu; Zu-Sheng, Zhou; Feng-Li, Zhao; Rong, Liu; Xiang-Cheng, Kong; Jing-Xia, Zhao; Chang-Dong, Deng; Hong, Song; Jin-Tong, Liu; Xu-Wen, Dai; Jun-Hui, Yue; Qi, Yang; Da-Yong, He; Xiang, He; Qi, Le; Xiao-Ping, Li; Lin, Wang; Xiang-Jian, Wang; Hui-Zhou, Ma; Xiao-Yan, Zhao; Yan-Feng, Sui; Hai-Sheng, Guo; Chuang-Xin, Ma; Jian-Bing, Zhao; Peng, Chen

    2013-01-01T23:59:59.000Z

    IHEP, China is constructing a 100 MeV / 100 kW electron Linac for NSC KIPT, Ukraine. This linac will be used as the driver of a neutron source based on a subcritical assembly. In 2012, the injector part of the accelerator was pre-installed as a testing facility in the experimental hall #2 of IHEP. The injector beam and key hardware testing results were met the design goal. Recently, the injector testing facility was disassembled and all of the components for the whole accelerator have been shipped to Ukraine from China by ocean shipping. The installation of the whole machine in KIPT will be started in June, 2013. The construction progress, the design and testing results of the injector beam and key hardware are presented.

  16. Learning Scene Entries and Exits using Coherent Motion Regions

    E-Print Network [OSTI]

    Davis, James W.

    Learning Scene Entries and Exits using Coherent Motion Regions Matthew Nedrich and James W. Davis,jwdavis}@cse.ohio-state.edu Abstract. We present a novel framework to reliably learn scene entry and exit locations using coherent. Resultant entity entry and exit observations of the paths are then clustered and a reliability metric

  17. Unsupervised extraction of coherent regions for image based rendering

    E-Print Network [OSTI]

    Dragotti, Pier Luigi

    Unsupervised extraction of coherent regions for image based rendering Jesse Berent and Pier Luigi, UK {jesse.berent, p.dragotti}@imperial.ac.uk Abstract Image based rendering using undersampled light information. In pop-up light field rendering [18], the scene is segmented into coherent layers, usually

  18. Optical quantum swapping in a coherent atomic medium

    E-Print Network [OSTI]

    Aurelien Dantan

    2011-10-03T23:59:59.000Z

    We propose to realize a passive optical quantum swapping device which allows for the exchange of the quantum fluctuations of two bright optical fields interacting with a coherent atomic medium in an optical cavity. The device is based on a quantum interference process between the fields within the cavity bandwidth arising from coherent population trapping in the atomic medium.

  19. Fiber-based combined optical coherence and multiphoton endomicroscopy

    E-Print Network [OSTI]

    Chen, Zhongping

    Fiber-based combined optical coherence and multiphoton endomicroscopy Gangjun Liu Zhongping Chen #12;Journal of Biomedical Optics 16(3), 036010 (March 2011) Fiber-based combined optical coherence. The efficiency can be further increased by fusing more multimode fibers with the DCF. Simultaneous optical

  20. Mode coherence at megameter ranges in the North Pacific Ocean

    E-Print Network [OSTI]

    Wage, Kathleen

    Mode coherence at megameter ranges in the North Pacific Ocean Kathleen E. Wage, Matthew A and the Acoustical Society of America. #12;Mode coherence at megameter ranges in the North Pacific Ocean Kathleen E Thermometry of Ocean Climate ATOC and Alternate Source Test AST experiments. Vertical line arrays at Hawaii

  1. Coherence Progress: A Measure of Interestingness Based on Fixed Compressors

    E-Print Network [OSTI]

    Schmidhuber, Juergen

    Coherence Progress: A Measure of Interestingness Based on Fixed Compressors Tom Schaul, Leo Pape in observations to store them in a compact form, called a compressor. The search for interesting patterns can and the ability of the compressor to learn from observations. Coherence progress considers the increase

  2. Modular Quantum Memories Using Passive Linear Optics and Coherent Feedback

    E-Print Network [OSTI]

    Modular Quantum Memories Using Passive Linear Optics and Coherent Feedback Hendra I. Nurdin photon pulsed optical field has a conceptually simple modular realization using only passive linear optics and coherent feedback. We exploit the idea that two decaying optical cavities can be coupled

  3. Coherent beam-beam mode in the LHC

    E-Print Network [OSTI]

    Buffat, X; Giachino, R; Herr, W; Papotti, G; Pieloni, T; White, S

    2014-01-01T23:59:59.000Z

    Observations of single bunch beam-beam coherent modes during dedicated experiments in the LHC are presented. Their role in standard operation for physics is discussed and, in particular, candidates of beam-beam coherent mode driven unstable by the machine impedance are presented.

  4. The Quasi-Coherent Oscillations of SS Cygni

    E-Print Network [OSTI]

    Christopher W. Mauche

    1996-08-22T23:59:59.000Z

    Properties of the quasi-coherent oscillations in the extreme ultraviolet (EUV) flux of the dwarf nova SS Cygni are described, with emphasis on (1) the scaling between the period of the oscillation and the EUV flux and (2) the mean power spectra and waveforms. In addition, a quasi-coherent oscillation at \

  5. Quasi Light Fields: A Model of Coherent Image Formation

    E-Print Network [OSTI]

    Wornell, Gregory W.

    Quasi Light Fields: A Model of Coherent Image Formation Anthony Accardi and Gregory Wornell formation that strikes a balance between the simplicity of the light field and the comprehensive predictive power of Maxwell's equations, by extending the light field to coherent radiation. © 2009 Optical Society

  6. Coherent spinor dynamics in a spin-1 Bose condensate

    E-Print Network [OSTI]

    Loss, Daniel

    , for example, a Bose­Einstein condensate or a degenerate Fermi gas, the phase space accessible to low of coherent spin-changing collisions in a gas of spin-1 bosons. Starting with condensates occupying two spin of the gas, although it does not change the nature of the coherence of the condensate--indeed it has been

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

    E-Print Network [OSTI]

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

    2013-02-09T23:59:59.000Z

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

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

    E-Print Network [OSTI]

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

    2012-01-01T23:59:59.000Z

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

  9. Quantum coherence, time-translation symmetry and thermodynamics

    E-Print Network [OSTI]

    Matteo Lostaglio; Kamil Korzekwa; David Jennings; Terry Rudolph

    2015-04-13T23:59:59.000Z

    The first law of thermodynamics imposes not just a constraint on the energy-content of systems in extreme quantum regimes, but also symmetry-constraints related to the thermodynamic processing of quantum coherence. We show that this thermodynamic symmetry decomposes any quantum state into mode operators that quantify the coherence present in the state. We then establish general upper and lower bounds for the evolution of quantum coherence under arbitrary thermal operations, valid for any temperature. We identify primitive coherence manipulations and show that the transfer of coherence between energy levels manifests irreversibility not captured by free energy. Moreover, the recently developed thermo-majorization relations on block-diagonal quantum states are observed to be special cases of this symmetry analysis.

  10. Initial scientific uses of coherent synchrotron radiation in electron storage rings

    E-Print Network [OSTI]

    2004-01-01T23:59:59.000Z

    The coherent synchrotron radiation at BESSY was used to1 using the coherent synchrotron radiation at BESSY show thecoherent synchrotron radiation source at BESSY. The results

  11. Swept source optical coherence microscopy for pathological assessment of cancerous tissues

    E-Print Network [OSTI]

    Ahsen, Osman Oguz

    2013-01-01T23:59:59.000Z

    Optical coherence microscopy (OCM) combines optical coherence tomography (OCT) with confocal microscopy and enables depth resolved visualization of biological specimens with cellular resolution. OCM offers a suitable ...

  12. Coherent Research Plan for the 3rd Generation Advanced high Strength...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Coherent Research Plan for the 3rd Generation Advanced high Strength Steels for Automotive Applications Coherent Research Plan for the 3rd Generation Advanced high Strength Steels...

  13. Surface plasmon polariton induced strong coherent superposition

    E-Print Network [OSTI]

    Sintayehu Tesfa; Ali A. Kamli

    2013-03-30T23:59:59.000Z

    A strong coherent superposition is shown to be induced between the energy states of a two-level emitter immersed in a surface plasmon polariton evanescently confined to a small metallic ring. It turns out that there is nearly equal chance for the two-level emitter to be found either in the upper or lower energy level at steady state even for a weaker surface plasmon driving strength. This indicates that it is possible to create a qubit that is robust against emitter spontaneous damping rate, which can be applicable in designing a device that can perform certain quantum information processing tasks. In support of this proposal, the photon statistics of the emitted radiation is found to exhibit significant nonclassical features.

  14. Birefringence insensitive optical coherence domain reflectometry system

    DOE Patents [OSTI]

    Everett, Matthew J. (Livermore, CA); Davis, Joseph G. (Lafayette, CA)

    2002-01-01T23:59:59.000Z

    A birefringence insensitive fiber optic optical coherence domain reflectometry (OCDR) system is provided containing non-polarization maintaining (non-PM) fiber in the sample arm and the reference arm without suffering from signal degradation caused by birefringence. The use of non-PM fiber significantly reduces the cost of the OCDR system and provides a disposable or multiplexed section of the sample arm. The dispersion in the reference arm and sample arm of the OCDR system are matched to achieve high resolution imaging. This system is useful in medical applications or for non-medical in situ probes. The disposable section of non-PM fiber in the sample arm can be conveniently replaced when contaminated by a sample or a patient.

  15. Communication via entangled coherent quantum network

    E-Print Network [OSTI]

    A. El Allati; Y. Hassouni; N. Metwally

    2010-11-17T23:59:59.000Z

    A quantum network is constructed via maximum entangled coherent states. The possibility of using this network to achieve communication between multi-participants is investigated. We showed that the probability of teleported unknown state successfully, depends on the size the used network. As the numbers of participants increases, the successful probability does not depend on the intensity of the field. The problem of implementing quantum teleportation protocol via a noise quantum network is discussed. We show one can send information perfectly with small values of the field intensity and larger values of the noise strength. The successful probability of this suggested protocol increases abruptly for larger values of the noise strength and gradually for small values. We show that for small size of the used quantum network, the fidelity of the teleported state decreases smoothly, while it decreases abruptly for larger size of network.

  16. Generating coherent states of entangled spins

    SciTech Connect (OSTI)

    Yu Hongyi; Luo Yu; Yao Wang [Department of Physics and Center of Theoretical and Computational Physics, University of Hong Kong (Hong Kong)

    2011-09-15T23:59:59.000Z

    A coherent state of many spins contains quantum entanglement, which increases with a decrease in the collective spin value. We present a scheme to engineer this class of pure state based on incoherent spin pumping with a few collective raising or lowering operators. In a pumping scenario aimed for maximum entanglement, the steady state of N-pumped spin qubits realizes the ideal resource for the 1{yields}(N/2) quantum telecloning. We show how the scheme can be implemented in a realistic system of atomic spin qubits in an optical lattice. Error analysis shows that high-fidelity state engineering is possible for N{approx}O(100) spins in the presence of decoherence. The scheme can also prepare a resource state for the secret sharing protocol and for the construction of the large-scale Affleck-Kennedy-Lieb-Tasaki state.

  17. Fabrication, Tuning, Treatment and Testing of Two 3.5 Cell Photo-Injektor Cavities for the ELBE Linac

    E-Print Network [OSTI]

    Arnold, A; Teichert, J; Xiang, R; Eremeev, G V; Kneisel, P; Stirbet, M; Turlington, L

    2011-01-01T23:59:59.000Z

    As part of a CRADA (Cooperative Research and Development Agreement) between Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and Thomas Jefferson Lab National Accelerator Facility (TJNAF) we have fabricated and tested two 1.3 GHz 3.5 cell photo-injector cavities from polycrystalline RRR niobium and large grain RRR niobium, respectively. The cavity with the better performance will replace the presently used injector cavity in the ELBE linac [1]. The cavities have been fabricated and pre-tuned at TJNAF, while the more sophisticated final field tuning; the adjustment of the external couplings and the field profile measurement of transverse electric modes for RF focusing [2] was done at HZDR. The following standard surface treatment and the vertical test were carried out at TJNAF’s production facilities. A major challenge turned out to be the rinsing of the cathode cell, which has small opening (Ø10 mm) to receive the cathode stalk. Another unexpected problem encountered after etching, since large visible defects a...

  18. Unambiguous coherent state identification: Searching a quantum database

    E-Print Network [OSTI]

    Michal Sedlak; Mario Ziman; Ondrej Pribyla; Vladimir Buzek; Mark Hillery

    2007-07-23T23:59:59.000Z

    We consider an unambiguous identification of an unknown coherent state with one of two unknown coherent reference states. Specifically, we consider two modes of an electromagnetic field prepared in unknown coherent states alpha_1 and alpha_2, respectively. The third mode is prepared either in the state alpha_1 or in the state alpha_2. The task is to identify (unambiguously) which of the two modes are in the same state. We present a scheme consisting of three beamsplitters capable to perform this task. Although we don't prove the optimality, we show that the performance of the proposed setup is better than the generalization of the optimal measurement known for a finite-dimensional case. We show that a single beamsplitter is capable to perform an unambiguous quantum state comparison for coherent states optimally. Finally we propose an experimental setup consisting of 2N-1 beamsplitters for unambiguous identification among N unknown coherent states. This setup can be considered as a search in a quantum database. The elements of the database are unknown coherent states encoded in different modes of an electromagnetic field. The task is to specify the two modes that are excited in the same, though unknown, coherent state.

  19. Gluon Radiation and Coherent States in Ultrarelativistic Nuclear Collisions

    E-Print Network [OSTI]

    Sergei G. Matinyan; Berndt Mueller; Dirk H. Rischke

    1997-05-14T23:59:59.000Z

    We explore the correspondence between classical gluon radiation and quantum radiation in a coherent state for gluons produced in ultrarelativistic nuclear collisions. The expectation value of the invariant momentum distribution of gluons in the coherent state is found to agree with the gluon number distribution obtained classically from the solution of the Yang-Mills equations. A criterion for the applicability of the coherent state formalism to the problem of radiation in ultrarelativistic nucleus-nucleus collisions is discussed. This criterion is found to be fulfilled for midrapidity gluons with perturbative transverse momenta larger than about 1-2 GeV and produced in collisions between valence partons.

  20. Coherent structures in compressible free-shear-layer flows

    SciTech Connect (OSTI)

    Aeschliman, D.P.; Baty, R.S. [Sandia National Labs., Albuquerque, NM (United States). Engineering Sciences Center; Kennedy, C.A.; Chen, J.H. [Sandia National Labs., Livermore, CA (United States). Combustion and Physical Sciences Center

    1997-08-01T23:59:59.000Z

    Large scale coherent structures are intrinsic fluid mechanical characteristics of all free-shear flows, from incompressible to compressible, and laminar to fully turbulent. These quasi-periodic fluid structures, eddies of size comparable to the thickness of the shear layer, dominate the mixing process at the free-shear interface. As a result, large scale coherent structures greatly influence the operation and efficiency of many important commercial and defense technologies. Large scale coherent structures have been studied here in a research program that combines a synergistic blend of experiment, direct numerical simulation, and analysis. This report summarizes the work completed for this Sandia Laboratory-Directed Research and Development (LDRD) project.

  1. Coherent state of a weakly interacting ultracold Fermi gas

    E-Print Network [OSTI]

    Arnab Ghosh; Sudarson Sekhar Sinha; Deb Shankar Ray

    2013-04-04T23:59:59.000Z

    We examine the weakly interacting atoms in an ultracold Fermi gas leading to a state of macroscopic coherence, from a theoretical perspective. It has been shown that this state can be described as a fermionic coherent state. These coherent states are the eigenstates of fermionic annihilation operators, the eigenvalues being anti-commuting numbers or Grassmann numbers. By exploiting the simple rules of Grassmann algebra and a close kinship between relations evaluated for more familiar bosonic fields and those for fermionic fields, we derive the thermodynamic limit, the spontaneous symmetry breaking and the quasi-particle spectrum of the fermionic system.

  2. Impact of the spatial laser distribution on photocathode gun operation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhou, Feng; Brachmann, Axel; Emma, Paul; Gilevich, Sasha; Huang, Zhirong

    2012-09-01T23:59:59.000Z

    It is widely believed that a drive laser with uniform temporal and spatial laser profiles is required to generate the lowest emittance beam at the photoinjector. However, for a given 3 ps smooth-Gaussian laser temporal profile, our recent simulations indicate that a truncated-Gaussian laser spatial profile produces an electron beam with smaller emittance. The simulation results are qualitatively confirmed by later analytical calculation, and also confirmed by measurements: emittance reduction of ?25% was observed at the linac coherent light source (LCLS) injector with a truncated-Gaussian laser spatial profile at the nominal operating bunch charge of 150 pC. There was a significant secondary benefit—laser transmission through the iris for the truncated-Gaussian profile was about twice that compared to the nearly uniform distribution, which significantly loosens the laser power and quantum efficiency requirements for drive laser system and photocathode. Since February 9, 2012, the drive laser with the truncated-Gaussian spatial distribution has been used for LCLS routine user operations and the corresponding free electron laser power is at least the same as the one when using the nearly uniform spatial profile.

  3. Principles of longitudinal beam diagnostics with coherent radiation

    E-Print Network [OSTI]

    problems and experiments are listed. After a brief introduction in Sect. 1, the radiation spectrum emitted bunch compressor. The form factors are computed according to Eq. (5). The coherence effect

  4. Coherent feedback that beats all measurement-based feedback protocols

    E-Print Network [OSTI]

    Jacobs, Kurt

    We show that when the speed of control is bounded, there is a widely applicable minimal-time control problem for which a coherent feedback protocol is optimal, and is faster than all measurement-based feedback protocols, ...

  5. Finite blocklength analysis of the MISO Coherent Block Fading Channel

    E-Print Network [OSTI]

    Collins, Austin Daniel

    2014-01-01T23:59:59.000Z

    The Coherent MISO Block Fading Channel is a wireless communication channel model in which the transmitter has access to multiple antennas while the receiver has access to one. This model is becoming increasingly important ...

  6. Optimizing directory-based cache coherence on the RAW architecture

    E-Print Network [OSTI]

    Ramaswamy, Satish

    2005-01-01T23:59:59.000Z

    Caches help reduce the effect of long-latency memory requests, by providing a high speed data-path to local memory. However, in multi-processor systems utilizing shared memory, cache coherence protocols are necessary to ...

  7. Shifted-elementary-mode representation for partially coherent vectorial fields

    E-Print Network [OSTI]

    Tervo, Jani; Vahimaa, Pasi; Wyrowski, Frank

    2010-01-01T23:59:59.000Z

    A representation of partially spatially coherent and partially polarized stationary electromagnetic fields is given in terms of mutually uncorrelated, transversely shifted, fully coherent and polarized elementary electric-field modes. This representation allows one to propagate non-paraxial partially coherent vector fields using techniques for spatially fully coherent fields, which are numerically far more efficient than methods for propagating correlation functions. A procedure is given to determine the elementary modes from the radiant intensity and the far-zone polarization properties of the entire field. The method is applied to quasihomogeneous fields with rotationally symmetric cosine-modulated radiant intensity distributions. This is an adequate model for fields emitted by, e.g., many light-emitting diodes.

  8. Ecological coherence of Natura2000 protected areas in Scotland 

    E-Print Network [OSTI]

    Winstrup, Mie

    2012-11-29T23:59:59.000Z

    important for ecological coherence (representivity, replication, patch sizes and shapes, and connectivity). In this study, a method is presented that addresses all of the above criteria for three main Annex I habitats in Scotland (Caledonian woodland, Tilio...

  9. Coherent radar ice thickness measurements over the Greenland ice sheet

    E-Print Network [OSTI]

    Gogineni, S. Prasad; Tammana, Dilip; Braaten, David A.; Leuschen, C.; Legarsky, J.; Kanagaratnam, P.; Stiles, J.; Allen, C.; Jezek, K.; Akins, T.

    2001-12-27T23:59:59.000Z

    We developed two 150-MHz coherent radar depth sounders for ice thickness measurements over the Greenland ice sheet. We developed one of these using connectorized components and the other using radio frequency integrated circuits (RFICs). Both...

  10. anatomical optical coherence: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ivan; Wang, Yimin; Chen, Zhongping 2004-01-01 3 Coherent Communication with Linear Optics Quantum Physics (arXiv) Summary: We show how to implement several continuous-variable...

  11. Studying coherence in ultra-cold atomic gases

    E-Print Network [OSTI]

    Miller, Daniel E. (Daniel Edward)

    2007-01-01T23:59:59.000Z

    This thesis will discuss the study of coherence properties of ultra-cold atomic gases. The atomic systems investigated include a thermal cloud of atoms, a Bose-Einstein condensate and a fermion pair condensate. In each ...

  12. Observation of Coherent Beam-beam Effects in the LHC

    E-Print Network [OSTI]

    Buffat, X; Giachino, R; Herr, W; Papotti, G; Pieloni, T; Calaga, R; White, S M

    2011-01-01T23:59:59.000Z

    Early collisions in the LHC with a very limited number of bunches with high intensities indicated the presence of coherent beam-beam driven oscillations. Here we discuss the experimental results and compare with the expectations.

  13. Quantum coherence, time-translation symmetry and thermodynamics

    E-Print Network [OSTI]

    Matteo Lostaglio; Kamil Korzekwa; David Jennings; Terry Rudolph

    2014-10-16T23:59:59.000Z

    The first law of thermodynamics imposes not just a constraint on the energy-content of systems in extreme quantum regimes, but also symmetry-constraints related to the thermodynamic processing of quantum coherence. Harmonic analysis allows any density operator to be decomposed in terms of mode operators which quantify the coherence present in a state in a natural way. We establish upper and lower bounds for the evolution of such modes under arbitrary thermal operations, and analyse primitive coherence manipulations. Well-studied thermo-majorization relations on block-diagonal quantum states correspond to constraints only on the zero-mode of a state, governing energy transfers. A complete set of constraints for non-zero modes, governing coherence transfers, is at present unknown, but these modes are found to display similar irreversibility, which demands greater study.

  14. Ultrahigh speed optical coherence tomography for ophthalmic imaging applications

    E-Print Network [OSTI]

    Liu, Jonathan Jaoshin

    2014-01-01T23:59:59.000Z

    Optical coherence tomography (OCT) is a non-contact, non-invasive, micron-scale optical imaging technology that has become a standard clinical tool in ophthalmology. Fourier domain OCT detection methods have enabled higher ...

  15. Development of Molecular Contrast in Coherence Domain Optical Imaging

    E-Print Network [OSTI]

    Wan, Qiujie

    2012-02-14T23:59:59.000Z

    . This technique could be used potentially as a clinical tool for diagnosing different progression stages of melanoma. This technique could also be applied to differentiate other mixed chromophores. Second harmonic optical coherence tomography (SHOCT) is non...

  16. Doppler optical coherence microscopy for studies of cochlear mechanics

    E-Print Network [OSTI]

    Hong, Stanley S.

    The possibility of measuring subnanometer motions with micron scale spatial resolution in the intact mammalian cochlea using Doppler optical coherence microscopy (DOCM) is demonstrated. A novel DOCM system is described ...

  17. Coherent instabilities in a semiconductor laser with fast gain recovery

    E-Print Network [OSTI]

    Wang, Christine Y.; Diehl, L.; Gordon, A.; Jirauschek, C.; Kartner, F. X.; Belyanin, Alexey; Bour, D.; Corzine, S.; Hofler, G.; Troccoli, M.; Faist, J.; Capasso, Federico

    2007-01-01T23:59:59.000Z

    We report the observation of a coherent multimode instability in quantum cascade lasers (QCLs), which is driven by the same fundamental mechanism of Rabi oscillations as the elusive Risken-Nummedal-Graham-Haken (RNGH) instability predicted 40 years...

  18. Quasi light fields: Extending the light field to coherent radiation

    E-Print Network [OSTI]

    Accardi, Anthony J.

    Imaging technologies such as dynamic viewpoint generation are engineered for incoherent radiation using the traditional light field, and for coherent radiation using electromagnetic field theory. We present a model of ...

  19. Robust Decoupling Techniques to Extend Quantum Coherence in Diamond

    E-Print Network [OSTI]

    Ryan, Colm A.

    We experimentally demonstrate over 2 orders of magnitude increase in the room-temperature coherence time of nitrogen-vacancy centers in diamond by implementing decoupling techniques. We show that equal pulse spacing ...

  20. Coherence characterization with a superconducting flux qubit through NMR approaches

    E-Print Network [OSTI]

    Yan, Fei, Ph. D. Massachusetts Institute of Technology

    2013-01-01T23:59:59.000Z

    This thesis discusses a series of experimental studies that investigate the coherence properties of a superconducting persistent-current or flux qubit, a promising candidate for developing a scalable quantum processor. A ...

  1. Low-coherent WDM reflectometry for accurate fiber length monitoring

    E-Print Network [OSTI]

    Hui, Rongqing; Thomas, J.; Allen, Christopher Thomas; Fu, B.; Gao, S.

    2003-01-01T23:59:59.000Z

    A fiber-optic low-coherent reflectometer was developed to accurately monitor fiber length variation. A large length-coverage range was obtained by using a fiber Bragg grating array in a wavelength-division-multiplexing ...

  2. Magnetism studies using resonant, coherent, x-ray scattering...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magnetism studies using resonant, coherent, x-ray scattering Monday, September 10, 2012 - 10:00am SLAC, Bldg. 137, Room 226 Keoki Seu Seminar: With the advent of free electron...

  3. Femtosecond time-resolved spectroscopy of coherent oscillations in nanomaterials 

    E-Print Network [OSTI]

    Jerebtsov, Serguei Nikolaevich

    2009-05-15T23:59:59.000Z

    pump-probe technique was applied for studies of acoustic vibrations in nanoparticles and nanowires, and coherent optical phonons in thin films. The elastic properties of spherical Ag nanoparticles and Ag and Bi nanowires were studied in a dual...

  4. Top marine predators track Lagrangian coherent structures

    E-Print Network [OSTI]

    E. Tew Kai; V. Rossi; J. Sudre; H. Weimerskirch; C. Lopez; E. Hernandez-Garcia; F. Marsac; V. Garcon

    2009-04-13T23:59:59.000Z

    Meso- and submesoscales (fronts, eddies, filaments) in surface ocean flow have a crucial influence on marine ecosystems. Their dynamics partly control the foraging behaviour and the displacement of marine top predators (tuna, birds, turtles, and cetaceans). In this work we focus on the role of submesoscale structures in the Mozambique Channel on the distribution of a marine predator, the Great Frigatebird. Using a newly developed dynamical concept, namely the Finite-Size Lyapunov Exponent (FSLE), we have identified Lagrangian coherent structures (LCSs) present in the surface flow in the Channel over a 2-month observation period (August and September 2003). By comparing seabirds' satellite positions with LCSs locations, we demonstrate that frigatebirds track precisely these structures in the Mozambique Channel, providing the first evidence that a top predator is able to track these FSLE ridges to locate food patches. After comparing bird positions during long and short trips, and different parts of these trips, we propose several hypotheses to understand how frigatebirds can follow these LCSs. The birds might use visual and/or olfactory cues and/or atmospheric current changes over the structures to move along these biological corridors. The birds being often associated to tuna schools around foraging areas, a thorough comprehension of their foraging behaviour and movement during the breeding season is crucial not only to seabirds' ecology but also to an appropriate ecosystemic approach of fisheries in the Channel.

  5. Coherent feedback that beats all measurement-based feedback protocols

    E-Print Network [OSTI]

    Kurt Jacobs; Xiaoting Wang; Howard M. Wiseman

    2014-07-21T23:59:59.000Z

    We show that when the speed of control is bounded, there is a widely applicable minimal-time control problem for which a coherent feedback protocol is optimal, and is faster than all measurement-based feedback protocols, where the latter are defined in a strict sense. The superiority of the coherent protocol is due to the fact that it can exploit a geodesic path in Hilbert space, a path that measurement-based protocols cannot follow.

  6. A Coherent Perceptron for All-Optical Learning

    E-Print Network [OSTI]

    Nikolas Tezak; Hideo Mabuchi

    2015-03-28T23:59:59.000Z

    We present nonlinear photonic circuit models for constructing programmable linear transformations and use these to realize a coherent Perceptron, i.e., an all-optical linear classifier capable of learning the classification boundary iteratively from training data through a coherent feedback rule. Through extensive semi-classical stochastic simulations we demonstrate that the device nearly attains the theoretical error bound for a model classification problem.

  7. A Coherent Perceptron for All-Optical Learning

    E-Print Network [OSTI]

    Tezak, Nikolas

    2015-01-01T23:59:59.000Z

    We present nonlinear photonic circuit models for constructing programmable linear transformations and use these to realize a coherent Perceptron, i.e., an all-optical linear classifier capable of learning the classification boundary iteratively from training data through a coherent feedback rule. Through extensive semi-classical stochastic simulations we demonstrate that the device nearly attains the theoretical error bound for a model classification problem.

  8. Quantum coherence phenomena in x-ray optics

    E-Print Network [OSTI]

    Anisimov, Petr Mikhailovich

    2009-05-15T23:59:59.000Z

    QUANTUM COHERENCE PHENOMENA IN X-RAY OPTICS A Dissertation by PETR MIKHAILOVICH ANISIMOV Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY December... 2008 Major Subject: Physics QUANTUM COHERENCE PHENOMENA IN X-RAY OPTICS A Dissertation by PETR MIKHAILOVICH ANISIMOV Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR...

  9. Transfer information remotely via noise entangled coherent channels

    E-Print Network [OSTI]

    A. El Allati; N. Metwally; Y. Hassouni

    2010-02-11T23:59:59.000Z

    In this contribution, a generalized protocol of quantum teleportation is suggested to investigate the possibility of remotely transfer unknown multiparities entangled coherent state. A theoretical technique is introduced to generate maximum entangled coherent states which are used as quantum channels. We show that the mean photon number plays a central role on the fidelity of the transferred information. The noise parameter can be considered as a control parameter only for small values of the mean photon number.

  10. Coherent flash of light emitted by a cold atomic cloud

    SciTech Connect (OSTI)

    Chalony, M. [Institut Non Lineaire de Nice, Universite de Nice Sophia-Antipolis, CNRS, F-06560 Valbonne (France); Pierrat, R. [Institut Langevin, ESPCI ParisTech, CNRS UMR 7587, 10 rue Vauquelin, F-75005 Paris (France); Delande, D. [Laboratoire Kastler Brossel, UPMC-Paris 6, ENS, CNRS, 4 Place Jussieu, F-75005 Paris (France); Wilkowski, D. [Institut Non Lineaire de Nice, Universite de Nice Sophia-Antipolis, CNRS, F-06560 Valbonne (France); Centre for Quantum Technologies, National University of Singapore, 117543 Singapore (Singapore)

    2011-07-15T23:59:59.000Z

    When a resonant laser sent on an optically thick cold atomic cloud is abruptly switched off, a coherent flash of light is emitted in the forward direction. This transient phenomenon is observed due to the highly resonant character of the atomic scatterers. We analyze quantitatively its temporal properties and show very good agreement with theoretical predictions. Based on complementary experiments, the phase of the coherent field is reconstructed without interferometric tools.

  11. Improvement of dose distribution in breast radiotherapy using a reversible transverse magnetic field Linac-MR unit

    SciTech Connect (OSTI)

    Esmaeeli, A. D., E-mail: ali-esmaeeli-d@yahoo.com [Department of Physics, Rasht Branch, Islamic Azad University, Rasht, 41476-54919 (Iran, Islamic Republic of); Mahdavi, S. R. [Department of Medical Physics, Tehran University of Medical Sciences, Tehran, 14174 (Iran, Islamic Republic of)] [Department of Medical Physics, Tehran University of Medical Sciences, Tehran, 14174 (Iran, Islamic Republic of); Pouladian, M.; Bagheri, S. [Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, 14778-93855 (Iran, Islamic Republic of)] [Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, 14778-93855 (Iran, Islamic Republic of); Monfared, A. S. [Department of Medical Physics, Babol University of Medical Sciences, Babol, 47148-71167 (Iran, Islamic Republic of)] [Department of Medical Physics, Babol University of Medical Sciences, Babol, 47148-71167 (Iran, Islamic Republic of)

    2014-01-15T23:59:59.000Z

    Purpose: To investigate the improvement in dose distribution in tangential breast radiotherapy using a reversible transverse magnetic field that maintains the same direction of Lorentz force between two fields. The investigation has a potential application in future Linac-MR units. Methods: Computed tomography images of four patients and magnetic fields of 0.25–1.5 Tesla (T) were used for Monte Carlo simulation. Two patients had intact breast while the other two had mastectomy. Simulations of planning and chest wall irradiation were similar to the actual clinical process. The direction of superior-inferior magnetic field for the medial treatment beam was reversed for the lateral beam. Results: For the ipsilateral lung and heart mean doses were reduced by a mean (range) of 45.8% (27.6%–58.6%) and 26.0% (20.2%–38.9%), respectively, depending on various treatment plan setups. The mean V{sub 20} for ipsilateral lung was reduced by 55.0% (43.6%–77.3%). In addition acceptable results were shown after simulation of 0.25 T magnetic field demonstrated in dose-volume reductions of the heart, ipsilateral lung, and noninvolved skin. Conclusions: Applying a reversible magnetic field during breast radiotherapy, not only reduces the dose to the lung and heart but also produces a sharp drop dose volume histogram for planning target volume, because of bending of the path of secondary charged particles toward the chest wall by the Lorentz force. The simulations have shown that use of the magnetic field at 1.5 T is not feasible for clinical applications due to the increase of ipsilateral chest wall skin dose in comparison to the conventional planning while 0.25 T is suitable for all patients due to dose reduction to the chest wall skin.

  12. HOM damping properties of fundamental power couplers in the superconducting electron gun of the energy recovery LINAC at Brookhaven National Laboratory

    SciTech Connect (OSTI)

    Hammons, L.; Hahn, H.

    2011-03-28T23:59:59.000Z

    Among the accelerator projects under construction at the Relativistic Heavy Ion Collider (RHIC) is an R and D energy recovery LINAC (ERL) test facility. The ERL includes both a five-cell superconducting cavity as well as a superconducting, photoinjector electron gun. Because of the high-charge and high-current demands, effective higher-order mode (HOM) damping is essential, and several strategies are being pursued. Among these is the use of the fundamental power couplers as a means for damping some HOMs. Simulation studies have shown that the power couplers can play a substantial role in damping certain HOMs, and this presentation discusses these studies along with measurements.

  13. Center for Beam Physics

    E-Print Network [OSTI]

    Chattopadhyay, S.

    2010-01-01T23:59:59.000Z

    Brookhaven). We have joined the LCLS (Linac Coherent LightCoherent Light Source (LCLS) project. A major new activityplaya leading role in the LCLS collaboration in the theory/

  14. Prudence in estimating coherence between planetary, solar and climate oscillations

    E-Print Network [OSTI]

    Holm, Sverre

    2015-01-01T23:59:59.000Z

    There are claims that there is correlation between the speed of center of mass of the solar system and the global temperature anomaly. This is partly grounded in data analysis and partly in a priori expectations. The magnitude squared coherence function is the proper measure for testing such claims. It is not hard to produce high coherence estimates at periods around 15--22 and 50--60 years between these data sets. This is done in two independent ways, by wavelets and by a periodogram method. But does a coherence of high value mean that there is coherence of high significance? In order to investigate that, four different measures for significance are studied. Due to the periodic nature of the data, only Monte Carlo simulation based on a non-parametric random phase method is appropriate. None of the high values of coherence then turn out to be significant. Coupled with a lack of a physical mechanism that can connect these phenomena, the planetary hypothesis is therefore dismissed.

  15. Dynamics of disentanglement, density matrix, and coherence in neutrino oscillations

    SciTech Connect (OSTI)

    Wu Jun; Boyanovsky, Daniel [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Hutasoit, Jimmy A.; Holman, Richard [Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

    2010-07-01T23:59:59.000Z

    In charged current weak interaction processes, neutrinos are produced in an entangled state with the charged lepton. This correlated state is disentangled by the measurement of the charged lepton in a detector at the production site. We study the dynamical aspects of disentanglement, propagation, and detection, in particular, the conditions under which the disentangled state is a coherent superposition of mass eigenstates. The appearance and disappearance far-detection processes are described from the time evolution of this disentangled 'collapsed' state. The familiar quantum mechanical interpretation and factorization of the detection rate emerges when the quantum state is disentangled on time scales much shorter than the inverse oscillation frequency, in which case the final detection rate factorizes in terms of the usual quantum mechanical transition probability provided the final density of states is insensitive to the neutrino energy difference. We suggest possible corrections for short-baseline experiments. If the charged lepton is unobserved, neutrino oscillations and coherence are described in terms of a reduced density matrix obtained by tracing out an unobserved charged lepton. The diagonal elements in the mass basis describe the production of mass eigenstates whereas the off-diagonal ones provide a measure of coherence. It is shown that coherences are of the same order of the diagonal terms on time scales up to the inverse oscillation frequency, beyond which the coherences oscillate as a result of the interference between mass eigenstates.

  16. On The Power Of Coherently Controlled Quantum Adiabatic Evolutions

    E-Print Network [OSTI]

    Maria Kieferova; Nathan Wiebe

    2014-03-26T23:59:59.000Z

    A major challenge facing adiabatic quantum computing is that algorithm design and error correction can be difficult for adiabatic quantum computing. Recent work has considered addressing his challenge by using coherently controlled adiabatic evolutions in the place of classically controlled evolution. An important question remains: what is the relative power of controlled adiabatic evolution to traditional adiabatic evolutions? We address this by showing that coherent control and measurement provides a way to average different adiabatic evolutions in ways that cause their diabatic errors to cancel, allowing for adiabatic evolutions to combine the best characteristics of existing adiabatic optimizations strategies that are mutually exclusive in conventional adiabatic QIP. This result shows that coherent control and measurement can provide advantages for adiabatic state preparation. We also provide upper bounds on the complexity of simulating such evolutions on a circuit based quantum computer and provide sufficiency conditions for the equivalence of controlled adiabatic evolutions to adiabatic quantum computing.

  17. Design of coherent quantum observers for linear quantum systems

    E-Print Network [OSTI]

    Shanon L. Vuglar; Hadis Amini

    2015-01-27T23:59:59.000Z

    Quantum versions of control problems are often more difficult than their classical counterparts because of the additional constraints imposed by quantum dynamics. For example, the quantum LQG and quantum H infinity optimal control problems remain open. To make further progress, new, systematic and tractable methods need to be developed. This paper gives three algorithms for designing coherent observers, i.e., quantum systems that are connected to a quantum plant and their outputs provide information about the internal state of the plant. Importantly, coherent observers avoid measurements of the plant outputs. We compare our coherent observers with a classical (measurement-based) observer by way of an example involving an optical cavity with thermal and vacuum noises as inputs.

  18. Transverse Coherence of the LCLS X-Ray Beam

    SciTech Connect (OSTI)

    Not Available

    2010-12-01T23:59:59.000Z

    Self-amplifying spontaneous radiation free-electron lasers, such as the LCLS or the European X-FEL, rely on the incoherent, spontaneous radiation as the seed for the amplifying process. Though this method overcomes the need for an external seed source one drawback is the incoherence of the effective seed signal. The FEL process allows for a natural growth of the coherence because the radiation phase information is spread out within the bunch due to slippage and diffraction of the radiation field. However, at short wavelengths this spreading is not sufficient to achieve complete coherence. In this presentation we report on the results of numerical simulations of the LCLS X-ray FEL. From the obtained radiation field distribution the coherence properties are extracted to help to characterize the FEL as a light source.

  19. Coherent multiple-foil x-ray transition radiation

    SciTech Connect (OSTI)

    Moran, M.J.; Chang, B.; Schneider, M.B.

    1993-08-25T23:59:59.000Z

    Intense x-ray transition radiation can be generated when relativistic electrons pass through a multiple-foil target. When the foil spacing is periodic, the transition radiation can be spatially coherent with respect to the target period. The spatial coherence can be evident in the spectra and angular distributions of transition radiation from such targets. A series of experiments has measured coherent transition radiation distributions from multiple-foil targets (up to six foils) with spacings of 50 {mu}m and 100 {mu}m. The electron energy was about 75 MeV and the photon energies were about 200 eV. Agreement between calculation and experimental data is excellent.

  20. Coherent Quantum Filtering for Physically Realizable Linear Quantum Plants

    E-Print Network [OSTI]

    Igor G. Vladimirov; Ian R. Petersen

    2013-01-14T23:59:59.000Z

    The paper is concerned with a problem of coherent (measurement-free) filtering for physically realizable (PR) linear quantum plants. The state variables of such systems satisfy canonical commutation relations and are governed by linear quantum stochastic differential equations, dynamically equivalent to those of an open quantum harmonic oscillator. The problem is to design another PR quantum system, connected unilaterally to the output of the plant and playing the role of a quantum filter, so as to minimize a mean square discrepancy between the dynamic variables of the plant and the output of the filter. This coherent quantum filtering (CQF) formulation is a simplified feedback-free version of the coherent quantum LQG control problem which remains open despite recent studies. The CQF problem is transformed into a constrained covariance control problem which is treated by using the Frechet differentiation of an appropriate Lagrange function with respect to the matrices of the filter.

  1. Transition from spatial coherence to incoherence in coupled chaotic systems

    E-Print Network [OSTI]

    Iryna Omelchenko; Bruno Riemenschneider; Philipp Hövel; Yuri Maistrenko; Eckehard Schöll

    2012-01-18T23:59:59.000Z

    We investigate the spatio-temporal dynamics of coupled chaotic systems with nonlocal interactions, where each element is coupled to its nearest neighbors within a finite range. Depending upon the coupling strength and coupling radius, we find characteristic spatial patterns such as wave-like profiles and study the transition from coherence to incoherence leading to spatial chaos. We analyze the origin of this transition based on numerical simulations and support the results by theoretical derivations identifying a critical coupling strength and a scaling relation of the coherent profiles. To demonstrate the universality of our findings we consider time-discrete as well as time-continuous chaotic models realized as logistic map and R\\"ossler or Lorenz system, respectively. Thereby we establish the coherence-incoherence transition in networks of coupled identical oscillators.

  2. Coherent Atom Optics with fast metastable rare gas atoms

    SciTech Connect (OSTI)

    Grucker, J.; Baudon, J.; Karam, J.-C.; Perales, F.; Vassilev, G.; Ducloy, M. [Laboratoire de Physique des Lasers, Universite Paris 13, Avenue J.B. Clement, 93430-Villetaneuse (France); Bocvarski, V. [Institute of Physics, Pregrevica 118, 11080 - Belgrade-Zemun (Serbia and Montenegro)

    2006-12-01T23:59:59.000Z

    Coherent atom optics experiments making use of an ultra-narrow beam of fast metastable atoms generated by metastability exchange are reported. The transverse coherence of the beam (coherence radius of 1.7 {mu}m for He*, 1.2 {mu}m for Ne*, 0.87 {mu}m for Ar*) is demonstrated via the atomic diffraction by a non-magnetic 2{mu}m-period reflection grating. The combination of the non-scalar van der Waals (vdW) interaction with the Zeeman interaction generated by a static magnetic field gives rise to ''vdW-Zeeman'' transitions among Zeeman sub-levels. Exo-energetic transitions of this type are observed with Ne*(3P2) atoms traversing a copper micro-slit grating. They can be used as a tunable beam splitter in an inelastic Fresnel bi-prism atom interferometer.

  3. Method and apparatus for coherent imaging of infrared energy

    DOE Patents [OSTI]

    Hutchinson, D.P.

    1998-05-12T23:59:59.000Z

    A coherent camera system performs ranging, spectroscopy, and thermal imaging. Local oscillator radiation is combined with target scene radiation to enable heterodyne detection by the coherent camera`s two-dimensional photodetector array. Versatility enables deployment of the system in either a passive mode (where no laser energy is actively transmitted toward the target scene) or an active mode (where a transmitting laser is used to actively illuminate the target scene). The two-dimensional photodetector array eliminates the need to mechanically scan the detector. Each element of the photodetector array produces an intermediate frequency signal that is amplified, filtered, and rectified by the coherent camera`s integrated circuitry. By spectroscopic examination of the frequency components of each pixel of the detector array, a high-resolution, three-dimensional or holographic image of the target scene is produced for applications such as air pollution studies, atmospheric disturbance monitoring, and military weapons targeting. 8 figs.

  4. Method and apparatus for coherent imaging of infrared energy

    DOE Patents [OSTI]

    Hutchinson, Donald P. (Knoxville, TN)

    1998-01-01T23:59:59.000Z

    A coherent camera system performs ranging, spectroscopy, and thermal imaging. Local oscillator radiation is combined with target scene radiation to enable heterodyne detection by the coherent camera's two-dimensional photodetector array. Versatility enables deployment of the system in either a passive mode (where no laser energy is actively transmitted toward the target scene) or an active mode (where a transmitting laser is used to actively illuminate the target scene). The two-dimensional photodetector array eliminates the need to mechanically scan the detector. Each element of the photodetector array produces an intermediate frequency signal that is amplified, filtered, and rectified by the coherent camera's integrated circuitry. By spectroscopic examination of the frequency components of each pixel of the detector array, a high-resolution, three-dimensional or holographic image of the target scene is produced for applications such as air pollution studies, atmospheric disturbance monitoring, and military weapons targeting.

  5. A Scalable Architecture for Coherence-Preserving Qubits

    E-Print Network [OSTI]

    Yaakov S. Weinstein; C. Stephen Hellberg

    2006-06-19T23:59:59.000Z

    We propose scalable architectures for the coherence-preserving qubits introduced by Bacon, Brown, and Whaley [Phys. Rev. Lett. {\\bf 87}, 247902 (2001)]. These architectures employ extra qubits providing additional degrees of freedom to the system. We show that these extra degrees of freedom can be used to counter errors in coupling strength within the coherence-preserving qubit and to combat interactions with environmental qubits. The presented architectures incorporate experimentally viable methods for inter-logical-qubit coupling and can implement a controlled phase gate via three simultaneous Heisenberg exchange operations. The extra qubits also provide flexibility in the arrangement of the physical qubits. Specifically, all physical qubits of a coherent-preserving qubit lattice can be placed in two spatial dimensions. Such an arrangement allows for universal cluster state computation.

  6. Cumulants, coherence, and contamination in multiparticle Bose-Einstein interferometry

    SciTech Connect (OSTI)

    Cramer, J.G.; Kadija, K. [Max-Planck-Institut fuer Physik, Muenchen, Germany Department of Physics FM--15, University of Washington, Seattle, Washington 98195 (United States)] [Max-Planck-Institut fuer Physik, Muenchen, Germany Department of Physics FM--15, University of Washington, Seattle, Washington 98195 (United States)

    1996-02-01T23:59:59.000Z

    We examine the formalism of multiparticle correlations used in Bose-Einstein interferometry with pions produced in ultrarelativistic heavy ion collisions. We include incoherent and quantum optics coherent contributions as well as the effect of contamination from particles included in the correlation that are not pions. We give expressions for the correlation functions and normalized cumulants for orders 2{endash}5 in the presence of these effects. We show that in the presence of coherence the normalized cumulants include an additional contribution besides that usually called the {open_quote}{open_quote}true{close_quote}{close_quote} multiparticle correlation. We also consider the {ital Q}=0 intercepts of the correlation functions and normalized cumulants in the presence of coherence and of contamination and show that values of the intercept of the normalized cumulant as a function of order can distinguish these two effects. {copyright} {ital 1996 The American Physical Society.}

  7. Chaos induced coherence in two independent food chains

    E-Print Network [OSTI]

    Adriana Auyuanet; Arturo C. Marti; Raul Montagne

    2005-07-20T23:59:59.000Z

    Coherence evolution of two food web models can be obtained under the stirring effect of chaotic advection. Each food web model sustains a three--level trophic system composed of interacting predators, consumers and vegetation. These populations compete for a common limiting resource in open flows with chaotic advection dynamics. Here we show that two species (the top--predators) of different colonies chaotically advected by a jet--like flow can synchronize their evolution even without migration interaction. The evolution is charaterized as a phase synchronization. The phase differences (determined through the Hilbert transform) of the variables representing those species show a coherent evolution.

  8. Coherent-feedback quantum control with a dynamic compensator

    E-Print Network [OSTI]

    Hideo Mabuchi

    2008-03-13T23:59:59.000Z

    I present an experimental realization of a coherent-feedback control system that was recently proposed for testing basic principles of linear quantum stochastic control theory [M. R. James, H. I. Nurdin and I. R. Petersen, to appear in IEEE Transactions on Automatic Control (2008), arXiv:quant-ph/0703150v2]. For a dynamical plant consisting of an optical ring-resonator, I demonstrate ~ 7 dB broadband disturbance rejection of injected laser signals via all-optical feedback with a tailored dynamic compensator. Comparison of the results with a transfer function model pinpoints critical parameters that determine the coherent-feedback control system's performance.

  9. Bremsstrahlung Radiation as Coherent State in Thermal QED

    E-Print Network [OSTI]

    Enke Wang; Jun Xiao; Hanzhong Zhang

    2001-10-23T23:59:59.000Z

    Based on fully finite temperature field theory we investigate the radiation probability in the bremsstrahlung process in thermal QED. It turns out that the infrared divergences resulting from the emission and absorption of the real photons are canceled by the virtual photon exchange processes at finite temperature. The full quantum calculation results for soft photons radiation coincide completely with that obtained in the semi-classical approximation. In the framework of Thermofield Dynamics it is shown that the bremsstrahlung radiation in thermal QED is a coherent state, the quasiclassical behavior of the coherent state leads to above coincidence.

  10. On the coherent behavior of pancreatic beta cell clusters

    E-Print Network [OSTI]

    Alessandro Loppini; Antonio Capolupo; Christian Cherubini; Alessio Gizzi; Marta Bertolaso; Simonetta Filippi; Giuseppe Vitiello

    2014-07-29T23:59:59.000Z

    Beta cells in pancreas represent an example of coupled biological oscillators which via communication pathways, are able to synchronize their electrical activity, giving rise to pulsatile insulin release. In this work we numerically analyze scale free self-similarity features of membrane voltage signal power density spectrum, through a stochastic dynamical model for beta cells in the islets of Langerhans fine tuned on mouse experimental data. Adopting the algebraic approach of coherent state formalism, we show how coherent molecular domains can arise from proper functional conditions leading to a parallelism with "phase transition" phenomena of field theory.

  11. Quatum Thermodynamics and the coherence in Ion channels

    E-Print Network [OSTI]

    Samyadeb Bhattacharya; Sisir Roy

    2013-05-02T23:59:59.000Z

    We showed that quantum mechanical superposition can sustain in the process of ion transfer in protein membrane for a substantial period, in spite of the presence of the interactions with environmental modes of molecular vibration. The spectral temperature, as defined in quantum thermodynamical framework plays a significant role in maintaining the coherence. The ratio of decoherence time and dwell time has been calculated, which can be directly related to the degree of coherence. The results shead new light to build quantum information system of entangled ionic states in the voltage gated biological channels.

  12. New Phase-coherent Measurements of Pulsar Braking Indices

    E-Print Network [OSTI]

    Margaret A. Livingstone; Victoria M. Kaspi; Fotis P. Gavriil; Richard N. Manchester; E. V. Gotthelf; Lucien Kuiper

    2007-02-07T23:59:59.000Z

    Pulsar braking indices offer insight into the physics that underlies pulsar spin-down. Only five braking indices have been measured via phase-coherent timing; all measured values are less than 3, the value expected from magnetic dipole radiation. Here we present new measurements for three of the five pulsar braking indices, obtained with phase-coherent timing for PSRs J1846-0258 (n=2.65+/-0.01), B1509-58 (n=2.839+/-0.001) and B0540-69 (n=2.140+/-0.009). We discuss the implications of these results and possible physical explanations for them.

  13. Quantum Coherence Conservation by Growth in Environmental Dissipation Rate

    E-Print Network [OSTI]

    SaiToh, Akira; Nakahara, Mikio

    2007-01-01T23:59:59.000Z

    Quantum coherence conservation is shown to be achieved by a very high rate of dissipation of an environmental system coupled with a principal system. This effect is not in the list of previously-known effects of noise suppression, such as Zeno effect, dynamical decoupling, quantum error correction code, and decoherence free subspace. An analytical solution is found for a simplified model of a single qubit coupled with an environmental single qubit dissipating rapidly. We also show examples of coherence conservation in a spin-boson linear coupling model with a numerical evaluation.

  14. Quantum Coherence Conservation by Growth in Environmental Dissipation Rate

    E-Print Network [OSTI]

    Akira SaiToh; Robabeh Rahimi; Mikio Nakahara

    2007-10-23T23:59:59.000Z

    Quantum coherence conservation is shown to be achieved by a very high rate of dissipation of an environmental system coupled with a principal system. This effect is not in the list of previously-known strategies of noise suppression, such as Zeno effect, dynamical decoupling, quantum error correction code, and decoherence free subspace. An analytical solution is found for a simplified model of a single qubit coupled with an environmental single qubit dissipating rapidly. We also show examples of coherence conservation in a spin-boson linear coupling model with a numerical evaluation.

  15. Dihedral symmetry of periodic chain: quantization and coherent states

    E-Print Network [OSTI]

    Luft, P; Tolar, J

    2007-01-01T23:59:59.000Z

    Our previous work on quantum kinematics and coherent states over finite configuration spaces is extended: the configuration space is, as before, the cyclic group $Z_{n}$ of arbitrary order n=2,3,..., but as its symmetry group a larger group -- the non-Abelian dihedral group $D_{n}$ -- is taken. The corresponding group related coherent states are constructed and their overcompleteness proved. Our approach based on geometric symmetry can be used as a kinematic framework for matrix methods in quantum chemistry of ring molecules.

  16. Coherent light transport in a cold Strontium cloud

    E-Print Network [OSTI]

    Y. Bibel; B. Klappauf; J. C. Bernard; D. Delande; G. Labeyrie; C. Miniatura; D. Wilkowski; R. Kaiser

    2002-02-05T23:59:59.000Z

    We study light coherent transport in the weak localization regime using magneto-optically cooled strontium atoms. The coherent backscattering cone is measured in the four polarization channels using light resonant with a J=0 to J=1 transition of the Strontium atom. We find an enhancement factor close to 2 in the helicity preserving channel, in agreement with theoretical predictions. This observation confirms the effect of internal structure as the key mechanism for the contrast reduction observed with an Rubidium cold cloud (see: Labeyrie et al., PRL 83, 5266 (1999)). Experimental results are in good agreement with Monte-Carlo simulations taking into account geometry effects.

  17. Do Finite-Size Lyapunov Exponents detect coherent structures?

    SciTech Connect (OSTI)

    Karrasch, Daniel; Haller, George, E-mail: georgehaller@ethz.ch [Institute of Mechanical Systems, ETH Zurich, Tannenstrasse 3, 8092 Zurich (Switzerland)] [Institute of Mechanical Systems, ETH Zurich, Tannenstrasse 3, 8092 Zurich (Switzerland)

    2013-12-15T23:59:59.000Z

    Ridges of the Finite-Size Lyapunov Exponent (FSLE) field have been used as indicators of hyperbolic Lagrangian Coherent Structures (LCSs). A rigorous mathematical link between the FSLE and LCSs, however, has been missing. Here, we prove that an FSLE ridge satisfying certain conditions does signal a nearby ridge of some Finite-Time Lyapunov Exponent (FTLE) field, which in turn indicates a hyperbolic LCS under further conditions. Other FSLE ridges violating our conditions, however, are seen to be false positives for LCSs. We also find further limitations of the FSLE in Lagrangian coherence detection, including ill-posedness, artificial jump-discontinuities, and sensitivity with respect to the computational time step.

  18. Evidence for color fluctuations in hadrons from coherent nuclear diffraction

    SciTech Connect (OSTI)

    Frankfurt, L. (Tel Aviv University, Ramat Aviv (Israel)); Miller, G.A. (Department of Physcis, FM-15, University of Washington, Seattle, Washington 98195 (United States)); Strikman, M. (Department of Physcis, Pennsylvania State University, University Park, Pennsylvania 16801 (United States))

    1993-11-01T23:59:59.000Z

    A QCD-based treatment of projectile size fluctuations is used to compute inelastic diffractive cross sections [sigma][sub diff] for coherent hadron-nuclear processes. We find that fluctuations near the average size give the major contribution to the cross section with [lt] few % contribution from small size configurations. The computed values of [sigma][sub diff] are consistent with the limited available data. The importance of coherent diffraction studies for a wide range of projectiles for high energy Fermilab fixed target experiments is emphasized. The implications of these significant color fluctuations for relativistic heavy ion collisions are discussed.

  19. EA-1087: Proposed Induction Linac System Experiments in Building 51B at Lawrence Berkeley National Laboratory, Berkeley, California

    Broader source: Energy.gov [DOE]

    This EA evaluates the environmental impacts of a proposal to modify existing Building 51B at the U.S. Department of Energy's Lawrence Berkeley National Laboratory to install and conduct experiments...

  20. Nuclear Data for Criticality Safety and Reactor Applications at the Gaerttner LINAC Center Y. Danon, R.M. Bahran, E.J. Blain, A.M. Daskalakis, B.J. McDermott, D.G. Williams

    E-Print Network [OSTI]

    Danon, Yaron

    Nuclear Data for Criticality Safety and Reactor Applications at the Gaerttner LINAC Center Y. Danon used in reactor and nuclear criticality safety applications. The goal of this program is to provide to nuclear criticality, neutron shielding applications, nuclear reactor design, and to better understand

  1. Neutron Transmission, Capture, and Scattering Measurements at the Gaerttner LINAC Center Y. Danon, L. Liu, E.J. Blain, A.M. Daskalakis, B.J. McDermott, K. Ramic, C.R. Wendorff

    E-Print Network [OSTI]

    Danon, Yaron

    Neutron Transmission, Capture, and Scattering Measurements at the Gaerttner LINAC Center Y. Danon . As the energy of the neutrons increases to the keV region neutron resonance scattering becomes dominant compared to capture, and scattered neutrons can penetrate the 10 B4C liner of the NaI capture detector and get

  2. Endoscopic optical coherence tomography for clinical studies in the gastrointestinal tract

    E-Print Network [OSTI]

    Tsai, Tsung-Han, Ph. D. Massachusetts Institute of Technology

    2013-01-01T23:59:59.000Z

    Optical coherence tomography (OCT) performs micrometer-scale, cross-sectional and three dimensional imaging by measuring the echo time delay of backscattered light. OCT imaging is performed using low-coherence interferometry. ...

  3. Coherent anti-Stokes Raman scattering (CARS) optimized by exploiting optical interference

    E-Print Network [OSTI]

    Wang, Xi

    2012-07-16T23:59:59.000Z

    The purpose of this work is to study the interference between the coherent nonresonant four-wave-mixing (FWM) background and the Raman-resonant signal in the coherent anti-Stokes Raman spectroscopy (CARS). The nonresonant background is usually...

  4. Optical measurement of neural action potentials using low coherence heterodyne interferometry

    E-Print Network [OSTI]

    Chu, Mark Changhao, 1978-

    2004-01-01T23:59:59.000Z

    We present a novel non-invasive optical method for detection of neural action potentials using low coherence interferometry. The dual beam heterodyne interferometer (DBHI) is a modified Michelson with a low coherence source ...

  5. Coherence Optimization of Vertical Cavity Semiconductor Optical Michael Snchez*a

    E-Print Network [OSTI]

    Esener, Sadik C.

    Coherence Optimization of Vertical Cavity Semiconductor Optical Amplifiers Michael Sánchez Dept., University of California - San Diego ABSTRACT Vertical cavity semiconductor optical amplifiers (VCSOAs) are attractive devices for use in coherent optical amplification, especially where 2-D amplifier

  6. Cellular resolution ex vivo imaging of gastrointestinal tissues with coherence microscopy

    E-Print Network [OSTI]

    Fujimoto, James G.

    Optical coherence microscopy (OCM) combines confocal microscopy and optical coherence tomography (OCT) to improve imaging depth and contrast, enabling cellular imaging in human tissues. We aim to investigate OCM for ex ...

  7. Spectral/ Fourier domain Doppler Optical Coherence Tomography in the rodent retina

    E-Print Network [OSTI]

    Liu, Jonathan Jaoshin

    2008-01-01T23:59:59.000Z

    Optical Coherence Tomography (OCT) is an emerging imaging technique based on low-coherence interferometry for noninvasive, high- resolution, cross-sectional imaging in a variety of biomedical fields. In ophthalmology, OCT ...

  8. Theory of femtosecond coherent anti-Stokes Raman backscattering enhanced by quantum coherence for standoff detection of bacterial spores

    E-Print Network [OSTI]

    Ooi, C. H. Raymond; Beadie, G.; Kattawar, George W.; Reintjes, J. F.; Rostovtsev, Y.; Zubairy, M. Suhail; Scully, Marlan O.

    2005-01-01T23:59:59.000Z

    .25.Fx I. INTRODUCTION Coherent Anti-Stokes Raman Spectroscopy #1;CARS#2; has been widely used in molecular spectroscopy #3;1#4;. The avail- ability of femtosecond lasers opens up new avenues for studying subpicosecond molecular dynamics #3...;2#4; and time re- solved CARS spectroscopy #3;3#4;. On the other hand, it has been shown that quantum coherence can dramatically in- crease the nonlinear response in atomic, molecular, or solid state media without significant absorption #3;4#4;. The subject...

  9. Klystron-linac combination

    DOE Patents [OSTI]

    Stein, W.E.

    1980-04-24T23:59:59.000Z

    A combination klystron-linear accelerator which utilizes anti-bunch electrons generated in the klystron section as a source of electrons to be accelerated in the accelerator section. Electron beam current is controlled by second harmonic bunching, constrictor aperture size and magnetic focusing. Rf coupling is achieved by internal and external coupling.

  10. Pulse power linac

    DOE Patents [OSTI]

    Villa, Francesco (Alameda, CA)

    1990-01-01T23:59:59.000Z

    A linear acceleration for charged particles is constructed of a plurality of transmission line sections that extend between a power injection region and an accelerating region. Each line section is constructed of spaced plate-like conductors and is coupled to an accelerating gap located at the accelerating region. Each gap is formed between a pair of apertured electrodes, with all of the electrode apertures being aligned along a particle accelerating path. The accelerating gaps are arranged in series, and at the injection region the line sections are connected in parallel. At the injection region a power pulse is applied simultaneously to all line sections. The line sections are graduated in length so that the pulse reaches the gaps in a coordinated sequence whereby pulse energy is applied to particles as they reach each of the gaps along the accelerating path.

  11. Alternating phase focused linacs

    DOE Patents [OSTI]

    Swenson, Donald A. (Los Alamos, NM)

    1980-01-01T23:59:59.000Z

    A heavy particle linear accelerator employing rf fields for transverse and ongitudinal focusing as well as acceleration. Drift tube length and gap positions in a standing wave drift tube loaded structure are arranged so that particles are subject to acceleration and succession of focusing and defocusing forces which contain the beam without additional magnetic or electric focusing fields.

  12. Final report: high resolution lensless 3D imaging of nanostructures with coherent x-rays

    SciTech Connect (OSTI)

    Jacobsen, Chris

    2014-12-07T23:59:59.000Z

    Final report on the project "High resolution lensless 3D imaging of nanostructures with coherent x-rays"

  13. ccsd00002004, Di usivity induced by vortex-like coherent

    E-Print Network [OSTI]

    in Reversed Field Pinch plasmas M. Spolaore x, V. Antoni, E. Spada, R. Cavazzana, E. Martines, G. Regnoli z, G Laboratory, Royal Institute of Technology, SE10044, Stockholm, Sweden Abstract. Coherent structures emerging of two Reversed Field Pinch experiments, RFX (Padua) and Extrap-T2R (Stockholm). Measurements have been

  14. Freie Universitt Berlin Transient reflectivity and coherent phonon

    E-Print Network [OSTI]

    Wolf, Martin

    Freie Universität Berlin Transient reflectivity and coherent phonon excitation: An ultrafast probe-Hubbard? . . . . . . 35 1.3.3 The photoinduced phase transition . . . . . . . . . . . . . . . . . . . 36 I #12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2.1.1 Generation of ultrashort laser pulses: the mode-locked Ti:Sapphire oscillator

  15. Quantum coherence phenomena in x-ray optics 

    E-Print Network [OSTI]

    Anisimov, Petr Mikhailovich

    2009-05-15T23:59:59.000Z

    effects in a three-level coherently driven system. Second, we show that the interference effects may appear in X-ray radiation at the nuclear transitions under the condition of the nuclear level anti-crossing. This effects are similar...

  16. Hanbury BrownTwiss effect with partially coherent electromagnetic beams

    E-Print Network [OSTI]

    Visser, Taco D.

    Hanbury Brown­Twiss effect with partially coherent electromagnetic beams Gaofeng Wu1,2 and Taco D fluctuations (the Hanbury Brown­Twiss effect) at two points in the same cross section of a random electro; (260.5430) Polarization. http://dx.doi.org/10.1364/OL.39.002561 Ever since Hanbury Brown­Twiss (HBT

  17. Calculating coherent pair production with Monte Carlo methods

    SciTech Connect (OSTI)

    Bottcher, C.; Strayer, M.R.

    1989-01-01T23:59:59.000Z

    We discuss calculations of the coherent electromagnetic pair production in ultra-relativistic hadron collisions. This type of production, in lowest order, is obtained from three diagrams which contain two virtual photons. We discuss simple Monte Carlo methods for evaluating these classes of diagrams without recourse to involved algebraic reduction schemes. 19 refs., 11 figs.

  18. Image analysis for the identification of coherent structures in plasma

    E-Print Network [OSTI]

    Kamath, Chandrika

    -based - and empirically evaluate their performance on four sample sequences. Our preliminary results indicate that while., Livermore, USA ABSTRACT Turbulence at the edge of the plasma in a nuclear fusion reactor can cause loss in experimental reactors. These images have indicated the presence of "coherent" structures which "retain

  19. Phased laser array with tailored spectral and coherence properties

    DOE Patents [OSTI]

    Messerly, Michael J; Dawson, Jay W; Beach, Raymond J

    2014-05-20T23:59:59.000Z

    Architectures for coherently combining an array of fiber-based lasers are provided. By matching their lengths to within a few integer multiples of a wavelength, the spatial and temporal properties of a single large laser are replicated, while extending the average or peak pulsed power limit.

  20. Quantum coherent switch utilizing commensurate nanoelectrode and charge density periodicities

    DOE Patents [OSTI]

    Harrison; Neil (Santa Fe, NM), Singleton; John (Los Alamos, NM), Migliori; Albert (Santa Fe, NM)

    2008-08-05T23:59:59.000Z

    A quantum coherent switch having a substrate formed from a density wave (DW) material capable of having a periodic electron density modulation or spin density modulation, a dielectric layer formed onto a surface of the substrate that is orthogonal to an intrinsic wave vector of the DW material; and structure for applying an external spatially periodic electrostatic potential over the dielectric layer.

  1. Adaptive optics enhanced simultaneous en-face optical coherence tomography

    E-Print Network [OSTI]

    Dainty, Chris

    Adaptive optics enhanced simultaneous en-face optical coherence tomography and scanning laser ophthalmoscopy David Merino and Chris Dainty Applied Optics Group, Department of Experimental Physics, National and Adrian Gh. Podoleanu Applied Optics Group, School of Physical Sciences, University of Kent at Canterbury

  2. Coherent coupling of diode lasers by phase conjugation

    SciTech Connect (OSTI)

    Cronin-Golomb, M.; Yariv, A.; Ury, I.

    1986-05-12T23:59:59.000Z

    We report experimental demonstrations of the use of a photorefractive barium titanate ring passive phase conjugate mirror in the coherent coupling of two GaAlAs diode lasers. By cooling the crystal towards its tetragonal to orthorhombic phase transition, we were also able to achieve infrared photorefractive phase conjugation with gain.

  3. Coherent coupling of diode lasers by phase conjugation

    SciTech Connect (OSTI)

    Cronin-Golomb; Yariv; Ury

    1986-05-12T23:59:59.000Z

    Experimental demonstrations are made of the use of a photorefractive barium titanate ring passive phase conjugate mirror in the coherent coupling of two GaAlAs diode lasers. By cooling the crystal towards its tetragonal to orthorhombic phase transition, one is able to achieve infrared photorefractive phase conjugation with gain.

  4. Femtosecond time-resolved spectroscopy of coherent oscillations in nanomaterials

    E-Print Network [OSTI]

    Jerebtsov, Serguei Nikolaevich

    2009-05-15T23:59:59.000Z

    . . . . . . . . . . . . . . . . . . 16 2. Regenerative amplifier . . . . . . . . . . . . . . . . . . 17 C. Transient Transmission Part . . . . . . . . . . . . . . . . . 19 III COHERENT ACOUSTIC VIBRATIONS IN NANOPARTI- CLES AND NANOWIRES ..................... 22 A. Optical Properties.... ................... 7 3 Kerr-lensing effect. ............................ 9 4 Principle of a CPA process. ....................... 10 5 Schematic of the grating stretcher a) and compressor b). ....... 11 6 Regenerative cavity. ........................... 12 7 Schematic...

  5. Optical Coherence Tomography for Neurosurgical Imaging of Human Intracortical Melanoma

    E-Print Network [OSTI]

    Boppart, Stephen

    Optical Coherence Tomography for Neurosurgical Imaging of Human Intracortical Melanoma Stephen A an intracortical melanoma. INSTRUMENTATION: OCT is a new, noncontact, high-speed imaging technology capable for imaging within the surgical field. Cadaveric human cortex with metastatic melanoma was harvested

  6. USING OPTICAL COHERENCE TOMOGRAPHY TO EXAMINE THE SUBSURFACE MORPHOLOGY OF

    E-Print Network [OSTI]

    Barton, Jennifer K.

    : (1) a homogeneous glassy phase; (2) a liquid­liquid phase separated state; and (3) a crystallizedUSING OPTICAL COHERENCE TOMOGRAPHY TO EXAMINE THE SUBSURFACE MORPHOLOGY OF CHINESE GLAZES M of their glazes. The images revealed unique phase assemblage modes in different samples. The results suggest

  7. COUPLING AND COHERENCE ESTIMATES FROM SINGLE-FIRED CYLINDRICAL EXPLOSIONS

    E-Print Network [OSTI]

    Stump, Brian W.

    COUPLING AND COHERENCE ESTIMATES FROM SINGLE-FIRED CYLINDRICAL EXPLOSIONS Implications for Using 4 5 6 7 8 test bench pit charge depth burden charge length explosive stemming #12;Single shot) Modeling - Source a) Explosion Source Mueller-Murphy model b) Vertical Spall Opening of horizontal crack

  8. Locally stationary wavelet coherence with application to neuroscience

    E-Print Network [OSTI]

    Fryzlewicz, Piotr

    Locally stationary wavelet coherence with application to neuroscience Jean Sanderson1 and Piotr extensively in neuroscience in order to study the interdependence between two simultaneously recorded signals (Pereda et al. (2005)). Neurophysiological time series are inherently non-stationary, and the detection

  9. Optimal energy-preserving conversions of quantum coherence

    E-Print Network [OSTI]

    Yuxiang Yang; Giulio Chiribella

    2015-03-05T23:59:59.000Z

    Quantum mechanics owes its name to the fact that certain physical quantities, like the energy of a hydrogen atom or the spin of an electron, are discrete. But even more distinctive is the existence of coherent superpositions, which provide an invaluable resource for quantum information processing and quantum technologies. The characterization, quantification, and manipulation of this resource are currently the object of intense research and are expected to contribute to the design of new high-performance quantum devices. In this paper we address the search for the best evolution that converts a given quantum superposition of energy eigenstates into another without exchang- ing energy with the surrounding environment. We consider both deterministic and probabilistic evolutions, obtained by measuring the environment and postselecting a subset of the outcomes. In both cases, we characterize the process that maximizes the fidelity with the target superposition. This characterization is used to design a branching sequence of probabilistic filters that increase the probability of success while reaching maximum fidelity at each iteration. We then show that a coherent superposition of different histories generated by such branching allows one to construct efficient approximations of the optimal fidelity-probability tradeoff, via a technique dubbed coherent coarse-graining. The benefits of our construction are illustrated in a number of applications to phase estimation, quantum cloning, coherent state amplification, and ancilla-driven computation.

  10. Orthogonality effects in the coherent nuclear production of jets

    SciTech Connect (OSTI)

    Jennings, B.K. (TRIUMF, Vancouver, British Columbia, V6T 2A3 (Canada)); Miller, G.A. (Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States))

    1994-12-01T23:59:59.000Z

    Previous calculations of coherent jet production in pion nucleus scattering use a plane wave approximation that violates the orthogonality of the initial and final state wave functions. We argue that such plane wave approximations give the correct [ital A] and transverse momentum dependence, but overestimate the magnitude of the cross section.

  11. On blind searches for noise dominated signals: a loosely coherent approach

    E-Print Network [OSTI]

    Vladimir Dergachev

    2010-08-23T23:59:59.000Z

    We introduce a "loosely coherent" method for detection of continuous gravitational waves that bridges the gap between semi-coherent and purely coherent methods. Explicit control over accepted families of signals is used to increase sensitivity of power-based statistic while avoiding the high computational costs of conventional matched filters. Several examples as well as a prototype implementation are discussed.

  12. PHYSICAL REVIEW E 87, 062704 (2013) Quantum coherence and entanglement in the avian compass

    E-Print Network [OSTI]

    Kais, Sabre

    2013-01-01T23:59:59.000Z

    PHYSICAL REVIEW E 87, 062704 (2013) Quantum coherence and entanglement in the avian compass James A of compass sensitivity. However, even if the initial spin state is neither entangled nor coherent, coherences in the radical- pair mechanism for the chemical compass, we can connect the chemical compass model with quantum

  13. Coherent-control of linear signals: Frequency-domain analysis Shaul Mukamel

    E-Print Network [OSTI]

    Mukamel, Shaul

    Coherent-control of linear signals: Frequency-domain analysis Shaul Mukamel Citation: The Journal, 164113 (2013) Coherent-control of linear signals: Frequency-domain analysis Shaul Mukamela) Department al.1 had demonstrated the coherent control of the photoisomerization of Rhodophin to linear order

  14. Coherent Instabilities of ILC Damping Ring

    SciTech Connect (OSTI)

    Heifets, S.; Stupakov, G.; Bane, K.; /SLAC

    2006-09-27T23:59:59.000Z

    The paper presents the first attempt to estimates the ILC damping ring impedance and compare thresholds of the classical instabilities for several designs initially proposed for the DR. The work was carried out in the spring of 2006. Since then the choice of the DR is narrowed. Nevertheless, the analysis described may be useful for the next iterations of the beam stability. Overall, the conventional instabilities will have little impact on the ring performance provided the careful design of the ring minimizes the impedance below acceptable level indicated above. The only exception is the transverse CB instability. The longitudinal CB is less demanding. However, even the transverse CB instability would have threshold current above nominal provided the aperture in the wigglers is increased from 8 mm to 16 mm. The microwave instability needs more studies. Nevertheless, we should remember that the ILC DR is different from existing high-current machines at least in two respects: absence of the beam-beam tune spread stabilizing beams in colliders, and unusual strict requirements for low emittance. That may cause new problems such as bunch emittance dilution due to high-frequency wakes (BPMs, grooves), etc. Even if such a possibility exists, it probably universal for all machines and ought be addressed in the design of vacuum components rather than have effect on the choice of the machine design.

  15. Treatment plan comparison of Linac step and shoot,Tomotherapy, RapidArc, and Proton therapy for prostate cancer using dosimetrical and biological index

    E-Print Network [OSTI]

    Lee, Suk; Chang, Kyung Hwan; Shim, Jang Bo; Kim, Kwang Hyeon; Lee, Nam Kwon; Park, Young Je; Kim, Chul Yong; Cho, Sam Ju; Lee, Sang Hoon; Min, Chul Kee; Kim, Woo Chul; Cho, Kwang Hwan; Huh, Hyun Do; Lim, Sangwook; Shin, Dongho

    2015-01-01T23:59:59.000Z

    The purpose of this study was to use various dosimetrical indices to determine the best IMRT modality technique for treating patients with prostate cancer. Ten patients with prostate cancer were included in this study. Intensity modulated radiation therapy plans were designed to include different modalities, including the linac step and shoot, Tomotherapy, RapidArc, and Proton systems. Various dosimetrical indices, like the prescription isodose to target volume (PITV) ratio, conformity index (CI), homogeneity index (HI), target coverage index (TCI), modified dose homogeneity index (MHI), conformation number (CN), critical organ scoring index (COSI), and quality factor (QF) were determined to compare the different treatment plans. Biological indices such as the generalized equivalent uniform dose (gEUD), based tumor control probability (TCP), and normal tissue complication probability (NTCP) were also calculated and used to compare the treatment plans. The RapidArc plan attained better PTV coverage, as evidenc...

  16. High-Temperature Quantum Coherence from Dissipative Environments

    E-Print Network [OSTI]

    George E. Cragg

    2014-11-14T23:59:59.000Z

    The Feynman-Vernon path integral formalism is used to derive the density matrix of a quantum oscillator that is linearly coupled to an environmental reservoir. Although low-temperature reservoirs thermalize the oscillator to the usual Boltzmann distribution, reservoirs at intermediate temperatures reduce this distribution to a single, coherent ground state. Associated with this state is an imaginary frequency indicating an environment which absorbs energy from the oscillator through the suppression of all excited modes. Further increase of the environmental temperature results again in the thermalization of the quantum oscillator to the expected Boltzmann distribution. Qualitatively, this result could account for high-temperature quantum effects including the superconducting properties of graphite grains as well as the quantum coherence observed in photosynthetic systems.

  17. Coherent data transmission with microresonator Kerr frequency combs

    E-Print Network [OSTI]

    Pfeifle, Joerg; Wegner, Daniel; Brasch, Victor; Herr, Tobias; Hartinger, Klaus; Li, Jingshi; Hillerkuss, David; Schmogrow, Rene; Holzwarth, Ronald; Freude, Wolfgang; Leuthold, Juerg; Kippenberg, Tobias J; Koos, Christian

    2013-01-01T23:59:59.000Z

    Optical frequency combs enable coherent data transmission on hundreds of wavelength channels and have the potential to revolutionize terabit communications. Generation of Kerr combs in nonlinear integrated microcavities represents a particularly promising option enabling line spacings of tens of GHz, compliant with wavelength-division multiplexing (WDM) grids. However, Kerr combs may exhibit strong phase noise and multiplet spectral lines, and this has made high-speed data transmission impossible up to now. Recent work has shown that systematic adjustment of pump conditions allows generating low phase-noise Kerr combs with singlet spectral lines. Here, by employing an integrated Si3N4 microresonator, we demonstrate that Kerr combs are suited for coherent data transmission with advanced modulation formats that pose stringent requirements on the spectral purity of the optical source. In our experiment, we encode a data stream of 392 Gbit/s on subsequent lines of a Kerr comb using quadrature phase shift keying (...

  18. Apparatus for generating coherent infrared energy of selected wavelength

    DOE Patents [OSTI]

    Stevens, Charles G. (Danville, CA)

    1985-01-01T23:59:59.000Z

    A tunable source (11) of coherent infrared energy includes a heat pipe (12) having an intermediate region (24) at which cesium (22) is heated to vaporizing temperature and end regions (27, 28) at which the vapor is condensed and returned to the intermediate region (24) for reheating and recirculation. Optical pumping light (43) is directed along the axis of the heat pipe (12) through a first end window (17) to stimulate emission of coherent infrared energy which is transmitted out through an opposite end window (18). A porous walled tubulation (44) extends along the axis of the heat pipe (12) and defines a region (46) in which cesium vapor is further heated to a temperature sufficient to dissociate cesium dimers which would decrease efficiency by absorbing pump light (43). Efficient generation of any desired infrared wavelength is realized by varying the wavelength of the pump light (43).

  19. Folded Compact Range Development and Coherent Change Detection Measurement Project

    SciTech Connect (OSTI)

    Sorensen, K.W.

    1995-03-01T23:59:59.000Z

    A novel, folded compact range configuration has been developed at the Sandia National Laboratories compact range antenna and radar cross section measurement facility, operated by the Radar/Antenna Department 2343, as a means of performing indoor, environmentally-controlled, far-field simulations of synthetic aperture radar (SAR) coherent change detection (CCD) measurements. This report describes the development of the folded compact range configuration, as well as the initial set of coherent change detection measurements made with the system. These measurements have been highly successful, and have demonstrated the viability of the folded compact range concept in simulating SAR CCD measurements. It is felt that follow-on measurements have the potential of contributing significantly to the body of knowledge available to the scientific community involved in CCD image generation and processing, and that this tool will be a significant aid in the research and development of change detection methodologies.

  20. Observation of detection-dependent multi-photon coherence times

    E-Print Network [OSTI]

    Young-Sik Ra; Malte C. Tichy; Hyang-Tag Lim; Osung Kwon; Florian Mintert; Andreas Buchleitner; Yoon-Ho Kim

    2015-01-12T23:59:59.000Z

    The coherence time constitutes one of the most critical parameters that determines whether or not interference is observed in an experiment. For photons, it is traditionally determined by the effective spectral bandwidth of the photon. Here we report on multi-photon interference experiments in which the multi-photon coherence time, defined by the width of the interference signal, depends on the number of interfering photons and on the measurement scheme chosen to detect the particles. A theoretical analysis reveals that all multi-photon interference with more than two particles features this dependence, which can be attributed to higher-order effects in the mutual indistinguishability of the particles. As a striking consequence, a single, well-defined many-particle quantum state can exhibit qualitatively different degrees of interference, depending on the chosen observable. Therefore, optimal sensitivity in many-particle quantum interferometry can only be achieved by choosing a suitable detection scheme.