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Sample records for impact linac coherent

  1. Linac Coherent Light Source Overview

    Office of Energy Efficiency and Renewable Energy (EERE)

    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

    ScienceCinema (OSTI)

    None

    2013-05-29

    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. The Linac Coherent Light Source

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

    White, William E.; Robert, Aymeric; Dunne, Mike

    2015-05-01

    The Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Laboratory was the first hard X-ray free-electron laser (FEL) to operate as a user facility. After five years of operation, LCLS is now a mature FEL user facility. Our personal views about opportunities and challenges inherent to these unique light sources are discussed.

  4. Linac Coherent Light SourCe

    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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousMathematicsEnergyInterested Parties - WAPA PublicLED ADOPTIONtoLighting SystemLinac Coherent Light SourCe

  5. 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.

    2015-03-09

    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

  6. 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

  7. SLAC Linac Coherent Light Source User Site

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

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  8. 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.

  9. Linac Coherent Light Source (LCLS) Bunch-Length Monitor using Coherent Radiation

    SciTech Connect (OSTI)

    Wu, Juhao; Emma, P.; /SLAC

    2007-03-21

    The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) based on the final kilometer of the Stanford Linear Accelerator. One of the most critical diagnostic devices is the bunch length monitor (BLM), which is to be installed right after each compressor utilizing coherent radiation from the last bending magnet. We describe the components and the optical layout of such a BLM. Based on the setup geometry, we discuss some issues about the coherent radiation signal.

  10. 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

    2015-01-01

    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.

  11. 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

    2015-07-01

    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

  12. 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

    2015-04-22

    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.

  13. X-ray detectors at the Linac Coherent Light Source

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

    Blaj, Gabriel; Caragiulo, Pietro; Carini, Gabriella; Carron, Sebastian; Dragone, Angelo; Freytag, Dietrich; Haller, Gunther; Hart, Philip; Hasi, Jasmine; Herbst, Ryan; et al

    2015-04-21

    Free-electron lasers (FELs) present new challenges for camera development compared with conventional light sources. At SLAC a variety of technologies are being used to match the demands of the Linac Coherent Light Source (LCLS) and to support a wide range of scientific applications. In this paper an overview of X-ray detector design requirements at FELs is presented and the various cameras in use at SLAC are described for the benefit of users planning experiments or analysts looking at data. Features and operation of the CSPAD camera, which is currently deployed at LCLS, are discussed, and the ePix family, a newmore »generation of cameras under development at SLAC, is introduced.« less

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

    SciTech Connect (OSTI)

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

    2008-09-24

    The Linac Coherent Light Source (LCLS) is the first x-ray laser user facility based upon a free electron laser (FEL) requiring extraordinary beam quality to saturate at 1.5 angstroms within a 100 meter undulator.[1] This new type of 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. Therefore a new RF gun or at least the modification of an existing gun was necessary. The parameters listed in Table 1 illustrate the unique characteristics of LCLS which drive the requirements for the electron gun as given in Table 2. The gun beam quality needs to accommodate emittance growth as the beam is travels through approximately one kilometer of linac and two bunch compressors before reaching the undulator. These beam requirements were demonstrated during the recent commissioning runs of the LCLS injector and linac [2] due to the successful design, fabrication, testing and operation of the LCLS gun. The goal of this paper is to relate the technical background of how the gun was able to achieve and in some cases exceed these requirements by understanding and correcting the deficiencies of the prototype s-band RF photocathode gun, the BNL/SLAC/UCLA Gun III. This paper begins with a brief history and technical description of Gun III and the Gun Test Facility (GTF) at SLAC, and studies of the gun's RF and emittance compensation solenoid. The work at the GTF identified the gun and solenoid deficiencies, and helped to define the specifications for the LCLS gun. Section 1.1.5 describes the modeling used to compute and correct the gun RF fields and Section 1.1.6 describes the use of these fields in the electron beam simulations. The magnetic design and measurements of the emittance compensation solenoid are discussed in Section 1.1.7. The novel feature of the LCLS solenoid is the embedded quadrupole correctors. The thermo-mechanical engineering of the LCLS gun is discussed in Section 1.1.8, and the cold and hot RF tests are described in Section 1.1.9. The results of this work are summarized and concluding remarks are given in Section 1.1.10.

  15. The X-ray correlation spectroscopy instrument at the Linac Coherent Light Source

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

    Alonso-Mori, Roberto; Caronna, Chiara; Chollet, Matthieu; Curtis, Robin; Damiani, Daniel S.; Defever, Jim; Feng, Yiping; Flath, Daniel L.; Glownia, James M.; Lee, Sooheyong; et al

    2015-03-03

    The X-ray Correlation Spectroscopy instrument is dedicated to the study of dynamics in condensed matter systems using the unique coherence properties of free-electron lasers. It covers a photon energy range of 4–25 keV. The intrinsic temporal characteristics of the Linac Coherent Light Source, in particular the 120 Hz repetition rate, allow for the investigation of slow dynamics (milliseconds) by means of X-ray photon correlation spectroscopy. Double-pulse schemes could probe dynamics on the picosecond timescale. In addition, a description of the instrument capabilities and recent achievements is presented.

  16. The Atomic, Molecular and Optical Science instrument at the Linac Coherent Light Source

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

    Ferguson, Ken R.; Bucher, Maximilian; Bozek, John D.; Carron, Sebastian; Castagna, Jean-Charles; Coffee, Ryan; Curiel, G. Ivan; Holmes, Michael; Krzywinski, Jacek; Messerschmidt, Marc; et al

    2015-05-01

    The Atomic, Molecular and Optical Science (AMO) instrument at the Linac Coherent Light Source (LCLS) provides a tight soft X-ray focus into one of three experimental endstations. The flexible instrument design is optimized for studying a wide variety of phenomena requiring peak intensity. There is a suite of spectrometers and two photon area detectors available. An optional mirror-based split-and-delay unit can be used for X-ray pump–probe experiments. Recent scientific highlights illustrate the imaging, time-resolved spectroscopy and high-power density capabilities of the AMO instrument.

  17. 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)

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  18. 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

    2015-04-10

    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

  19. 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

    2015-01-30

    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.

  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

    2015-01-30

    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

  1. Performance of a beam-multiplexing diamond crystal monochromator at the Linac Coherent Light Source

    SciTech Connect (OSTI)

    Zhu, Diling, E-mail: dlzhu@slac.stanford.edu; Feng, Yiping; Lemke, Henrik T.; Fritz, David M.; Chollet, Matthieu; Glownia, J. M.; Alonso-Mori, Roberto; Sikorski, Marcin; Song, Sanghoon; Williams, Garth J.; Messerschmidt, Marc; Boutet, Sébastien; Robert, Aymeric [Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stoupin, Stanislav; Shvyd'ko, Yuri V. [Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Terentyev, Sergey A.; Blank, Vladimir D. [Technological Institute of Superhard and Novel Carbon Materials, Tsentralnaya str. 7a, Troitsk, Moscow 142190 (Russian Federation); Driel, Tim B. van [Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Center for Molecular Movies, Department of Physics, Technical University of Denmark, DK-2800 Lyngby (Denmark)

    2014-06-15

    A double-crystal diamond monochromator was recently implemented at the Linac Coherent Light Source. It enables splitting pulses generated by the free electron laser in the hard x-ray regime and thus allows the simultaneous operations of two instruments. Both monochromator crystals are High-Pressure High-Temperature grown type-IIa diamond crystal plates with the (111) orientation. The first crystal has a thickness of ?100 ?m to allow high reflectivity within the Bragg bandwidth and good transmission for the other wavelengths for downstream use. The second crystal is about 300 ?m thick and makes the exit beam of the monochromator parallel to the incoming beam with an offset of 600 mm. Here we present details on the monochromator design and its performance.

  2. 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

    2015-05-28

    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

  3. 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

    2015-04-15

    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.

  4. Photon-in photon-out hard X-ray spectroscopy at the Linac Coherent Light Source

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

    Alonso-Mori, Roberto; Sokaras, Dimosthenis; Zhu, Diling; Kroll, Thomas; Chollet, Mathieu; Feng, Yiping; Glownia, James M.; Kern, Jan; Lemke, Henrik T.; Nordlund, Dennis; et al

    2015-04-15

    X-ray free-electron lasers (FELs) have opened unprecedented possibilities to study the structure and dynamics of matter at an atomic level and ultra-fast timescale. Many of the techniques routinely used at storage ring facilities are being adapted for experiments conducted at FELs. In order to take full advantage of these new sources several challenges have to be overcome. They are related to the very different source characteristics and its resulting impact on sample delivery, X-ray optics, X-ray detection and data acquisition. Here it is described how photon-in photon-out hard X-ray spectroscopy techniques can be applied to study the electronic structure andmore »its dynamics of transition metal systems with ultra-bright and ultra-short FEL X-ray pulses. In particular, some of the experimental details that are different compared with synchrotron-based setups are discussed and illustrated by recent measurements performed at the Linac Coherent Light Source.« less

  5. 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

    2014-01-01

    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

  6. 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

    2015-04-11

    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.

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

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

    as a whole. Thus, there would be no disproportionate effects on minority or low-income populations. S During operations, the Proposed Action would increase the number of...

  8. 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.

    2015-03-01

    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

  9. 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)

    2015-03-01

    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.

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

    SciTech Connect (OSTI)

    Stohr, J

    2011-11-16

    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.

  11. Impact of the MLC on the MRI field distortion of a prototype MRI-linac

    SciTech Connect (OSTI)

    Kolling, Stefan; Keall, Paul; Oborn, Brad

    2013-12-15

    Purpose: To cope with intrafraction tumor motion, integrated MRI-linac systems for real-time image guidance are currently under development. The multileaf collimator (MLC) is a key component in every state-of-the-art radiotherapy treatment system, allowing for accurate field shaping and tumor tracking. This work quantifies the magnetic impact of a widely used MLC on the MRI field homogeneity for such a modality.Methods: The finite element method was employed to model a MRI-linac assembly comprised of a 1.0?T split-bore MRI magnet and the key ferromagnetic components of a Varian Millennium 120 MLC, namely, the leaves and motors. Full 3D magnetic field maps of the system were generated. From these field maps, the peak-to-peak distortion within the MRI imaging volume was evaluated over a 30?cm diameter sphere volume (DSV) around the isocenter and compared to a maximum preshim inhomogeneity of 300??T. Five parametric studies were performed: (1) The source-to-isocenter distance (SID) was varied from 100 to 200?cm, to span the range of a compact system to that with lower magnetic coupling. (2) The MLC model was changed from leaves only to leaves with motors, to determine the contribution to the total distortion caused by MLC leaves and motors separately. (3) The system was configured in the inline or perpendicular orientation, i.e., the linac treatment beam was oriented parallel or perpendicular to the magnetic field direction. (4) The treatment field size was varied from 0 × 0 to 20×20?cm{sup 2}, to span the range of clinical treatment fields. (5) The coil currents were scaled linearly to produce magnetic field strengths B{sub 0} of 0.5, 1.0, and 1.5?T, to estimate how the MLC impact changes with B{sub 0}.Results: (1) The MLC-induced MRI field distortion fell continuously with increasing SID. (2) MLC leaves and motors were found to contribute to the distortion in approximately equal measure. (3) Due to faster falloff of the fringe field, the field distortion was generally smaller in the perpendicular beam orientation. The peak-to-peak DSV distortion was below 300??T at SID?130?cm (perpendicular) and SID?140?cm (inline) for the 1.0?T design. (4) The simulation of different treatment fields was identified to cause dynamic changes in the field distribution. However, the estimated residual distortion was below 1.2?mm geometric distortion at SID?120?cm (perpendicular) and SID?130?cm (inline) for a 10?mT/m frequency-encoding gradient. (5) Due to magnetic saturation of the MLC materials, the field distortion remained constant at B{sub 0}>1.0?T.Conclusions: This work shows that the MRI field distortions caused by the MLC cannot be ignored and must be thoroughly investigated for any MRI-linac system. The numeric distortion values obtained for our 1.0?T magnet may vary for other magnet designs with substantially different fringe fields, however the concept of modest increases in the SID to reduce the distortion to a shimmable level is generally applicable.

  12. 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)

    2012-03-19

    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.

  13. 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

    2012-07-05

    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).

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

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  15. SAC - Linac Coherent Light Source

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  16. SLAC Linac Coherent Light Source

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  17. Safety | Linac Coherent Light Source

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  18. High Resolution Simulation of Beam Dynamics in Electron Linacs for Free Electron Lasers

    SciTech Connect (OSTI)

    Ryne, R.D.; Venturini, M.; Zholents, A.A.; Qiang, J.

    2009-01-05

    In this paper we report on large scale multi-physics simulation of beam dynamics in electron linacs for next generation free electron lasers (FELs). We describe key features of a parallel macroparticle simulation code including three-dimensional (3D) space-charge effects, short-range structure wake fields, longitudinal coherent synchrotron radiation (CSR) wake fields, and treatment of radiofrequency (RF) accelerating cavities using maps obtained from axial field profiles. A macroparticle up-sampling scheme is described that reduces the shot noise from an initial distribution with a smaller number of macroparticles while maintaining the global properties of the original distribution. We present a study of the microbunching instability which is a critical issue for future FELs due to its impact on beam quality at the end of the linac. Using parameters of a planned FEL linac at Lawrence Berkeley National Laboratory (LBNL), we show that a large number of macroparticles (beyond 100 million) is needed to control numerical shot noise that drives the microbunching instability. We also explore the effect of the longitudinal grid on simulation results. We show that acceptable results are obtained with around 2048 longitudinal grid points, and we discuss this in view of the spectral growth rate predicted from linear theory. As an application, we present results from simulations using one billion macroparticles of the FEL linac under design at LBNL. We show that the final uncorrelated energy spread of the beam depends not only on the initial uncorrelated energy spread but also depends strongly on the shape of the initial current profile. By using a parabolic initial current profile, 5 keV initial uncorrelated energy spread at 40 MeV injection energy, and improved linac design, those simulations demonstrate that a reasonable beam quality can be achieved at the end of the linac, with the final distribution having about 100 keV energy spread, 2.4 GeV energy, and 1.2 kA peak current.

  19. Impact of Coherent Turbulence on Wind Turbine Aeroelastic Response and Its Simulation: Preprint

    SciTech Connect (OSTI)

    Kelley, N. D.; Jonkman, B. J.; Scott, G. N.; Bialasiewicz, J. T.; Redmond, L. S.

    2005-08-01

    In this paper, we present a brief overview of our recent research results regarding the impact of organized or coherent inflow turbulence on the dynamic response of operating wind turbines. Previous field experimentation has demonstrated that the greatest structural fatigue damage tends to occur during the nighttime hours from coherent turbulence that develops in the stable, nocturnal atmospheric boundary layer. We have found that under such conditions, intense vertical wind shear and temperature gradients create resonant flow fields that are capable of imparting short-period loading and vibrational energy as wind turbine rotor blades pass through regions of organized or coherent turbulence. This energy is subsequently propagated throughout the remainder of the structure, where it is often locally dissipated. We also briefly discuss our recent progress in developing a numerical simulation that includes such coherent inflow conditions that can be used to excite wind turbine design codes.

  20. Asymmetric Dual Axis Energy Recovery Linac for Ultra-High Flux sources of coherent X-ray/THz radiation: Investigations Towards its Ultimate Performance

    E-Print Network [OSTI]

    Ainsworth, R; Konoplev, I V; Seryi, A

    2015-01-01

    Truly compact and high current, efficient particle accelerators are required for sources of coherent high brightness and intensity THz and X-Ray radiation to be accepted by university or industrial R&D laboratories. The demand for compactness and efficiency can be satisfied by superconducting RF energy recovery linear accelerators (SRF ERL) allowing effectively minimising the footprint and maximising the efficiency of the system. However such set-ups are affected by regenerative beam-break up (BBU) instabilities which limit the beam current and may terminate the beam transport as well as energy recuperation. In this paper we suggest and discuss a SRF ERL with asymmetric configuration of accelerating and decelerating cavities resonantly coupled. In this model of SRF ERL we propose an electron bunch passing through accelerating and decelerating cavities each once and we show that in this case the regenerative BBU instability can be minimised allowing high currents to be achieved. We study the BBU start curr...

  1. LLRF System Upgrade for the SLAC Linac

    SciTech Connect (OSTI)

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

    2012-07-06

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

  2. After Beamtime | Linac Coherent Light Source

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  3. Collaborator Checklist | Linac Coherent Light Source

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  4. Committees & Contacts | Linac Coherent Light Source

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  5. Contact Us | Linac Coherent Light Source

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  6. Becoming a User | Linac Coherent Light Source

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  7. Bioimaging Workshop - Linac Coherent Light Source

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  8. LINAC Coherent Light Source | Department of Energy

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  9. Spokesperson Checklist | Linac Coherent Light Source

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  10. SLAC Linac Coherent Light Source User Site

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  11. SLAC Linac Coherent Light Source User Site

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  12. Proposal Submission | Linac Coherent Light Source

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  13. The Linac Coherent Light Source is

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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. Working at SLAC | Linac Coherent Light Source

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  18. LCLS Parameters Update | Linac Coherent Light Source

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  19. LCLS Policies | Linac Coherent Light Source

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  20. Food Options | Linac Coherent Light Source

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  1. 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

    2012-07-06

    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.

  2. R and D energy recovery LINAC at Brookhaven National Laboratory

    SciTech Connect (OSTI)

    Litvinenko,V.N.; Beavis, D.; Ben-Zvi, I.; Blaskiewicz, M.; Burrill, A.; Calaga, R.; Cameron, P.; Chang, X.; Drees, A.; Ganetis, G.; Gassner, D.; Hahn, H.; Hammons, L.; Hershcovitch, A.; Hseuh, H-C.; Jain, A.; Kayran, D.; Kewisch, J.; Lambiase, R.; Lederle, D.; Mahler, G.; McIntyre, G.; Meng, W.; Nehring, T.; Oerter, B.; Pai, C.; Pate, D.; Phillips, D.; Pozdeyev, E.; Rao, T.; Reich, J.; Roser, T.; Russo, T.; Smith, K.; Tuozzolo, J.; Weiss, D.; Williams, N.; Yip, K.; Zaltsman, A.; Favale, A.; Bluem, H.; Cole, M.; Holmes, D.; Rathke, J.; Schultheiss, T.; Todd, A.; Delayen, J.; Funk, L.; Phillips, L.; Preble, J.

    2008-06-23

    Collider Accelerator Department at BNL is in the final stages of developing the 20-MeV R and D energy recovery linac with super-conducting 2.5 MeV RF gun and single-mode super-conducting 5-cell RF linac. This unique facility aims to address many outstanding questions relevant for high current (up to 0.5 A of average current), high brightness energy-recovery linacs with novel ZigZag-type merger. Recent development in the R and D ERL plans include gun and 5-cell cavity (G5) test and possibility of using R and D ERL for proof-of-principle test of Coherent Electron Cooling at RHIC.

  3. Optimization of SRF Linacs

    SciTech Connect (OSTI)

    Powers, Tom [JLAB

    2013-09-01

    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.

  4. Linac Envelope Optics

    E-Print Network [OSTI]

    Baartman, Rick

    2015-01-01

    I develop the formalism that allows calculation of beam envelopes through a linear accelerator given its on-axis electric field. Space charge can naturally be added using Sacherer formalism. A complicating feature is that the reference particle's energy-time coordinates are not known a priori. Since first order matrix formalism applies to deviations from the reference particle, this means the reference particle's time and energy must be calculated simultaneously with the beam envelope and transfer matrix. The code TRANSOPTR is used to track envelopes for general elements whose infinitesimal transfer matrices are known, and in the presence of space charge. Incorporation of the linac algorithm into TRANSOPTR is described, and some examples given.

  5. Linear Vlasov solver for microbunching gain estimation with inclusion of CSR, LSC and linac geometric impedances

    E-Print Network [OSTI]

    Tsai, Cheng-Ying; Li, Rui; Tennant, Chris

    2015-01-01

    As is known, microbunching instability (MBI) has been one of the most challenging issues in designs of magnetic chicanes for short-wavelength free-electron lasers or linear colliders, as well as those of transport lines for recirculating or energy recovery linac machines. To more accurately quantify MBI in a single-pass system and for more complete analyses, we further extend and continue to increase the capabilities of our previously developed linear Vlasov solver [1] to incorporate more relevant impedance models into the code, including transient and steady-state free-space and/or shielding coherent synchrotron radiation (CSR) impedances, the longitudinal space charge (LSC) impedances, and the linac geometric impedances with extension of the existing formulation to include beam acceleration [2]. Then, we directly solve the linearized Vlasov equation numerically for microbunching gain amplification factor. In this study we apply this code to a beamline lattice of transport arc [3] following an upstream linac...

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

    E-Print Network [OSTI]

    Knyazik, Andrey

    2013-01-01

    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

  7. LFSC - Linac Feedback Simulation Code

    SciTech Connect (OSTI)

    Ivanov, Valentin; /Fermilab

    2008-05-01

    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.

  8. Commissioning of the 112 MHz SRF Gun and 500 MHz bunching cavities for the CeC PoP Linac

    SciTech Connect (OSTI)

    Belomestnykh, S.; Ben-Zvi, I.; Brutus, J. C.; Litvinenko, V.; McIntosh, P.; Moss, A.; Narayan, G.; Orfin, P.; Pinayev, I.; Rao, T.; Skaritka, J.; Smith, K.; Than, R.; Tuozzolo, J.; Wang, E.; Wheelhouse, A.; Wu, Q.; Xiao, B.; Xin, T.; Xu, W.; Zaltsman, A.

    2015-05-03

    The Coherent electron Cooling Proof-of-Principle (CeC PoP) experiment at BNL includes a short electron linac. During Phase 1, a 112 MHz superconducting RF photo-emission gun and two 500 MHz normal conducting bunching cavities were installed and are under commissioning. The paper describes the Phase1 linac layout and presents commissioning results for the cavities and associated RF, cryogenic and other sub-systems

  9. 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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  10. User Research Administration & Support | Linac Coherent Light Source

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

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  13. High Wavevector Temporal Speckle Correlations at the Linac Coherent Light

    Office of Scientific and Technical Information (OSTI)

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  14. 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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  15. 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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  16. 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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  17. 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

    2011-12-13

    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.

  18. Coherent electron cooling

    SciTech Connect (OSTI)

    Litvinenko,V.

    2009-05-04

    Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.

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

    E-Print Network [OSTI]

    2013-01-01

    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

  20. A Single-Shot Method for Measuring Femtosecond Bunch Length in Linac-Based Free-Electron Lasers

    SciTech Connect (OSTI)

    Huang, Z.; Bane, K.; Ding, Y.; Emma, P.; /SLAC

    2010-08-26

    There is growing interest in the generation and characterization of femtosecond and subfemtosecond pulses from linac-based free-electron lasers (FELs). In this report, following the method of Ricci and Smith [Phys. Rev. ST Accel. Beams 3, 032801 (2000)], we investigate the measurement of the longitudinal bunch profile of an ultrashort electron bunch produced by these FELs. We show that this method can be applied in a straightforward manner at x-ray FEL facilities such as the Linac Coherent Light Source by slightly adjusting the second bunch compressor followed by running the bunch on an rf zero-crossing phase of the final linac. We find that the linac wakefield strongly perturbs the measurement, and through analysis show that it can be compensated in a simple way. We demonstrate the effectiveness of this method and wakefield compensation through numerical simulations, including effects of coherent synchrotron radiation and longitudinal space charge. When used in conjunction with a high-resolution electron spectrometer, this method potentially reveals the temporal profile of the electron beam down to the femtosecond and subfemotsecond scale.

  1. Waveguide detuning caused by transverse magnetic fields on a simulated in-line 6 MV linac

    SciTech Connect (OSTI)

    St Aubin, J.; Steciw, S.; Fallone, B. G. [Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

    2010-09-15

    Purpose: Due to the close proximity of the linear accelerator (linac) to the magnetic resonance (MR) imager in linac-MR systems, it will be subjected to magnet fringe fields larger than the Earth's magnetic field of 5x10{sup -5} T. Even with passive or active shielding designed to reduce these fields, some magnitude of the magnetic field is still expected to intersect the linac, causing electron deflection and beam loss. This beam loss, resulting from magnetic fields that cannot be eliminated with shielding, can cause a detuning of the waveguide due to excessive heating. The detuning, if significant, could lead to an even further decrease in output above what would be expected strictly from electron deflections caused by an external magnetic field. Thus an investigation of detuning was performed through various simulations. Methods: According to the Lorentz force, the electrons will be deflected away from their straight course to the target, depositing energy as they impact the linac copper waveguide. The deposited energy would lead to a heating and deformation of the copper structure resulting in resonant frequency changes. PARMELA was used to determine the mean energy and fraction of total beam lost in each linac cavity. The energy deposited into the copper waveguide from the beam losses caused by transverse magnetic fields was calculated using the Monte Carlo program DOSRZnrc. From the total energy deposited, the rise in temperature and ultimately the deformation of the structure was estimated. The deformed structure was modeled using the finite element method program COMSOL MULTIPHYSICS to determine the change in cavity resonant frequency. Results: The largest changes in resonant frequency were found in the first two accelerating cavities for each field strength investigated. This was caused by a high electron fluence impacting the waveguide inner structures coupled with their low kinetic energies. At each field strength investigated, the total change in accelerator frequency was less than a manufacturing tolerance of 10 kHz and is thus not expected to have a noticeable effect on accelerator performance. Conclusions: The amount of beam loss caused by magnetic fringe fields for a linac in a linac-MR system depends on the effectiveness of its magnetic shielding. Despite the best efforts to shield the linac from the magnetic fringe fields, some persistent magnetic field is expected which would result in electron beam loss. This investigation showed that the detuning of the waveguide caused by additional electron beam loss in persistent magnetic fields is not a concern.

  2. S-Band Loads for SLAC Linac

    SciTech Connect (OSTI)

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

    2012-08-28

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

  3. 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

    2006-01-01

    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.

  4. A Stability of LCLS Linac Modulators

    SciTech Connect (OSTI)

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

    2012-06-13

    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. RF Power Generation in LINAC4

    E-Print Network [OSTI]

    Brunner, O; Schwerg, J N

    2010-01-01

    Linac4 is a lin­ear ac­cel­er­a­tor for neg­a­tive Hy­dro­gen ions (H-) which will re­place the old Linac2 as lin­ear in­jec­tor for the CERN ac­cel­er­a­tors. Its high­er en­er­gy of 160 MeV will give in­creased beam in­ten­si­ty in the down­stream ma­chines. Linac4 is about 100 m long, nor­mal-con­duct­ing, and will be housed in a tun­nel about 12 m below ground. The Linac4 tun­nel will be con­nect­ed to the ex­ist­ing chain of ac­cel­er­a­tors and can be ex­tend­ed to the new in­jec­tion chain. The high RF power for the Linac4 ac­cel­er­at­ing struc­tures will be gen­er­at­ed by thir­teen 1.3 MW klystrons, pre­vi­ous­ly used for the CERN LEP ac­cel­er­a­tor, and six new 2.8 MW klystrons of all op­er­at­ing at a fre­quen­cy of 352.2 MHz. The in­te­gra­tion of the RF power sys­tem in the build­ing is pre­sent­ed. The tech­ni­cal spec­i­fi­ca­tions and the per­for­mance of the var­i­ous high-pow­er el­e­ments are dis­cussed, ...

  6. Impact of Coherent Neutrino Nucleus Scattering on Direct Dark Matter Searches based on CaWO$_4$ Crystals

    E-Print Network [OSTI]

    A. Gütlein; G. Angloher; A. Bento; C. Bucci; L. Canonica; A. Erb; F. v. Feilitzsch; N. Ferreiro Iachellini; P. Gorla; D. Hauff; J. Jochum; M. Kiefer; H. Kluck; H. Kraus; J. -C. Lanfranchi; J. Loebell; A. Münster; F. Petricca; W. Potzel; F. Pröbst; F. Reindl; S. Roth; K. Rottler; C. Sailer; K. Schäffner; J. Schieck; S. Schönert; W. Seidel; M. v. Sivers; L. Stodolsky; C. Strandhagen; R. Strauss; A. Tanzke; M. Uffinger; A. Ulrich; I. Usherov; S. Wawoczny; M. Willers; M. Wüstrich; A. Zöller

    2015-03-17

    Atmospheric and solar neutrinos scattering coherently off target nuclei will be an important background source for the next generation of direct dark matter searches. In this work we focus on calcium tungstate as target material. For comparison with existing works we calculate the neutrino floor indicating which sensitivities can be reached before the neutrino background appears. In addition, we investigate the sensitivities of future direct dark matter searches using CRESST-II like detectors. Extending previous works we take into account achievable energy resolutions and thresholds as well as beta and gamma backgrounds for this investigation. We show that an exploration of WIMP-nucleon cross sections below the neutrino floor is possible for exposures of $\\gtrsim10$ kg-years or higher. In the third part we show that a first detection of coherent neutrino nucleus scattering of atmospheric and solar neutrinos using the same detectors and the backgrounds is feasible for exposures of $\\gtrsim50$ kg-years.

  7. Induction linacs for heavy ion fusion research

    SciTech Connect (OSTI)

    Fessenden, T.J.

    1984-05-01

    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. HIGH CURRENT ENERGY RECOVERY LINAC AT BNL.

    SciTech Connect (OSTI)

    LITVINENKO,V.N.; BEN-ZVI,I.; BARTON,D.S.; ET AL.

    2005-05-16

    We present the design and parameters of an energy recovery linac (ERL) facility, which is under construction in the Collider-Accelerator Department at BNL. This R&D facility has the goal of demonstrating CW operation of an ERL with an average beam current in the range of 0.1-1 ampere and with very high efficiency of energy recovery. The possibility of a future upgrade to a two-pass ERL is also being considered. The heart of the facility is a 5-cell 703.75 MHz super-conducting RF linac with strong Higher Order Mode (HOM) damping. The flexible lattice of the ERL provides a test-bed for exploring issues of transverse and longitudinal instabilities and diagnostics of intense CW electron beams. This ERL is also perfectly suited for a far-IR FEL. We present the status and plans for construction and commissioning of this facility.

  9. High Current Energy Recovery Linac at BNL

    SciTech Connect (OSTI)

    Vladimir N. Litvinenko; Donald Barton; D. Beavis; Ilan Ben-Zvi; Michael Blaskiewicz; J.M. Brennan; A. Burrill; R. Calaga; P. Cameron; X. Chang; Roger Connolly; D. Gassner; H. Hahn; A. Hershcovitch; H.C. Hseuh; P. Johnson; D. Kayran; J. Kewisch; R. Lambiase; G. McIntyre; W. Meng; T. C. Nehring; A. Nicoletti; D. Pate; J. Rank; T. Roser; T. Russo; J. Scaduto; K. Smith; T. Srinivasan-Rao; N. Williams; K.-C. Wu; Vitaly Yakimenko; K. Yip; A. Zaltsman; Y. Zhao; H. Bluem; A. Burger; Mike Cole; A. Favale; D. Holmes; John Rathke; Tom Schultheiss; A. Todd; J. Delayen; W. Funk; L. Phillips; Joe Preble

    2004-08-01

    We present the design, the parameters of a small test Energy Recovery Linac (ERL) facility, which is under construction at Collider-Accelerator Department, BNL. This R&D facility has goals to demonstrate CW operation of ERL with average beam current in the range of 0.1 - 1 ampere, combined with very high efficiency of energy recovery. A possibility for future up-grade to a two-pass ERL is considered. The heart of the facility is a 5-cell 700 MHz super-conducting RF linac with HOM damping. Flexible lattice of ERL provides a test-bed for testing issues of transverse and longitudinal instabilities and diagnostics of intense CW e-beam. ERL is also perfectly suited for a far-IR FEL. We present the status and our plans for construction and commissioning of this facility.

  10. Simulations for CLIC Drive Beam Linac

    E-Print Network [OSTI]

    Avni Aksoy

    2012-02-25

    The Drive Beam Linac of the Compact Linear Collider (CLIC) has to accelerate an electron beam with 4.2 A up to 2.4 GeV in almost fully-loaded structures. The pulse contains about 70000 bunches, one in every second rf bucket, and has a length of 140 $\\mu$s. The beam stability along the beamline is of concern for such a high current and pulse length. We present different options for the lattice of the linac based on FODO, triplet and doublet cells and compare the transverse instability for each lattice including the effects of beam jitter, alignment and beam-based correction. Additionally longitudinal stability is discussed for different bunch compressors using FODO type of lattice.

  11. Analysis on linac quadrupole misalignment in FACET commissioning 2012

    SciTech Connect (OSTI)

    Sun, Yipeng; /SLAC

    2012-07-05

    In this note, the analysis on linac quadrupole misalignment is presented for the FACET linac section LI05-09 plus LI11-19. The effectiveness of the beam-based alignment technique is preliminarily confirmed by the measurement. Beam-based alignment technique was adopted at SLAC linac since SLC time. Here the beam-based alignment algorithms are further developed and applied in the FACET commissioning during 2012 run.

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

    E-Print Network [OSTI]

    Qiang, Ji

    2014-01-01

    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

  13. High Power Superconducting Continuous Wave Linacs for Protons...

    Office of Science (SC) Website

    Power Superconducting Continuous Wave Linacs for Protons and Heavy-Ions Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Applications of...

  14. Catalytic Coherence

    E-Print Network [OSTI]

    Johan Aberg

    2014-10-20

    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.

  15. SNS LINAC MODULATOR OPERATIONAL HISTORY AND PERFOMANCE

    SciTech Connect (OSTI)

    Peplov, Vladimir V [ORNL; Anderson, David E [ORNL; Cutler, Roy I [ORNL; Hicks, Jim [ORNL; Saethre, Robert B [ORNL; Wezensky, Mark W [ORNL

    2011-01-01

    Fourteen High Voltage Converter Modulators (HVCM) were initially installed at the Spallation Neutron Source Linear Accelerator (SNS Linac) at the Oak Ridge National Laboratory in 2005. A fifteenth HVCM was added in 2009. Each modulator provides a pulse of up to 140 kV at a maximum width of 1.35 msec. Peak power level is 11 MW with an 8% duty factor. The HVCM system must be available for neutron production (NP) 24/7 with the exception being two, 6-week maintenance periods per year. HVCM reliability is one of the most important factors to maximize Linac availability and achieve SNS performance goals. During the last few years several modifications have been implemented to improve the overall system reliability. This paper presents operational history of the HVCM systems and examines failure mode statistical data since the modulators began operating at 60 Hz. System enhancements and upgrades aimed at providing long term reliable operation with minimal down time are also discussed in the paper.

  16. 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

    2008-01-01

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

  17. Space charge compensation on the low energy beam transport of Linac4

    E-Print Network [OSTI]

    AUTHOR|(SzGeCERN)733270; Scrivens, Richard; Jesus Castillo, Santos

    Part of the upgrade program in the injector chains of the CERN accelerator complex is the replacement of the the proton accelerator Linac2 for the brand new Linac4 which will accelerate H$^-$ and its main goal is to increase the beam intensity in the next sections of the LHC accelerator chain. The Linac4 is now under commissioning and will use several ion sources to produce high intensity unbunched H$^-$ beams with different properties, and the low energy beam transport (LEBT) is the system in charge of match all these different beams to the Radio frequency quadrupole (RFQ). The space charge forces that spread the beam ions apart of each other and cause emittance growth limits the maximum intensity that can be transported in the LEBT, but the space charge of intense unbunched ion beams can be compensated by the generated ions by the impact ionization of the residual gas, which creates a source of secondary particles inside the beam pipe. For negative ion beams, the effect of the beam electric field is to ex...

  18. R&D Energy Recovery Linac at Brookhaven National Laboratory

    SciTech Connect (OSTI)

    Litvinenko, Vladimir; Beavis, D.; Ben-Zvi, Ilan; Blaskiewicz, Michael; Burrill, Andrew; Calaga, Rama; Cameron, Peter; Chang, Xiangyun; Drees, K.A.; Ganetis, G.; Gamble, Michael; Hahn, H.; Hammons, L.R.; Hershcovitch, A.; Hseuh, H.C.; Jain, A.K.; Kayran, A.; Kewisch, Jorg; Lambiase, R.F.; Lederle, D.L.; Mahler, G.J.; McIntyre, G.; Meng, W.; Nehring, T.C.; Oerter, B.; Pai, C.; Pate, D.; Phillips, Daniel; Pozdeyev, Eduard; Rao, Triveni; Reich, J.; Roser, Thomas; Russo, T.; Smith, K.; Tuozzolo, Joseph; Weiss, D.; Williams, N.W.W.; Yip, Kin; Zaltsman, A.; Bluem, Hans; Cole, Michael; Favale, Anthony; Holmes, D.; Rathke, John; Schultheiss, Tom; Delayen, Jean; Funk, L.; Phillips, H.; Preble, Joseph

    2008-07-01

    Collider Accelerator Department at BNL is in the final stages of developing the 20-MeV R&D energy recovery linac with super-conducting 2.5 MeV RF gun and single-mode super-conducting 5-cell RF linac. This unique facility aims to address many outstanding questions relevant for high current (up to 0.5 A of average current), high brightness energy-recovery linacs with novel Zigzag-type merger. We present the performance of the R&D ERL elements and detailed commissioning plan.

  19. Coherent measures of the impact of co-authors in peer review journals and in proceedings publications

    E-Print Network [OSTI]

    Ausloos, Marcel

    2015-01-01

    This paper focuses on the coauthor effect in different types of publications, usually not equally respected in measuring research impact. {\\it A priori} unexpected relationships are found between the total coauthor core value, $m_a$, of a leading investigator (LI), and the related values for their publications in either peer review journals ($j$) or in proceedings ($p$). A surprisingly linear relationship is found: $ m_a^{(j)} + 0.4\\;m_a^{(p)} = m_a^{(jp)} $. Furthermore, another relationship is found concerning the measure of the total number of citations, $A_a$, i.e. the surface of the citation size-rank histogram up to $m_a$. Another linear relationship exists : $A_a^{(j)} + 1.36\\; A_a^{(p)} = A_a^{(jp)} $. These empirical findings coefficients (0.4 and 1.36) are supported by considerations based on an empirical power law found between the number of joint publications of an author and the rank of a coauthor. Moreover, a simple power law relationship is found between $m_a$ and the number ($r_M$) of coauthor...

  20. Simulation studies on laser pulse stability for Dalian Coherent Light Source

    E-Print Network [OSTI]

    Deng, Haixiao; Gu, Duan; Liu, Bo; Gu, Qiang; Wang, Dong

    2013-01-01

    Dalian Coherent Light Source will use a 300MeV LINAC to produce fully coherent photon pulses in the wavelength range between 150-50nm by high gain harmonic generation free electron laser (FEL) scheme. To generate stable FEL pulses, stringent tolerance budget is required for the LINAC output parameters, such as the mean beam energy stability, electron bunch arrival time jitter, peak current variation and the transverse beam position offset. In order to provide guidance for the design of the Dalian Coherent Light Source, in this paper, the sensitivity of FEL pulse energy fluctuation to various error sources of the electron bunch was performed using intensive start-to-end FEL simulations.

  1. Overview of High Intensity Linac Programs in Europe

    E-Print Network [OSTI]

    Garoby, R

    2004-01-01

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

  2. A drift-tube linac incorporating a ramped accelerating field

    SciTech Connect (OSTI)

    Liska, D.J.; Dauelsberg, L.B.

    1987-01-01

    A short, high-power linac structure has been designed and is being built; it incorporates a ramped accelerating field for matching a radio-frequency quadrupole (RFQ) to a high-gradient drift-tube linac (DTL). The tank is made of aluminum and can operate at high duty factor. The drift tubes are copper and use new neodymium-iron-boron quadrupoles. The linac is tuned using conical-sweep post couplers and is driven by multiple rf loops. Rapid acceleration of the beam occurs from low to high gradients in a short, compact, and lightweight structure. Because this linac will also be used to test open drift tubes, test results are included on vacuum measurements of high-grade epoxies and plastics that might be used in a drift-tube body.

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

    E-Print Network [OSTI]

    Atre, Mahesh Purushottam

    1992-01-01

    FREQUENCY AND AMPLITUDE CONTROL FOR AN EXPERIMENTAL LINAC RF DRIVE A Thesis by MAHESH PURUSHOTTAM ATRE Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE May 1992 Major Subject: Electrical Engineering FREQUENCY AND AMPLITUDE CONTROL FOR AN EXPERIMENTAL LINAC RF DRIVE A Thesis by MAHESH PURUSHOTTAM ATRE Approved as to style and content by: S. P. Bhattachary (Chair of Committee) arng Huang...

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

    SciTech Connect (OSTI)

    Constantin, Drago? E. Fahrig, Rebecca; Holloway, Lois; Keall, Paul J.

    2014-02-15

    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%.

  5. Coherence Properties of Individual Femtosecond Pulses of an X-ray Free-Electron Laser

    SciTech Connect (OSTI)

    Vartanyants, I.A.; /DESY /Moscow Phys. Eng. Inst.; Singer, A.; Mancuso, A.P.; Yefanov, O.M.; /DESY; Sakdinawat, A.; Liu, Y.; Bang, E.; /UC, Berkeley; Williams, G.J.; /SLAC; Cadenazzi, G.; Abbey, B.; /Melbourne U.; Sinn, H.; /European XFEL, Hamburg; Attwood, D.; /UC, Berkeley; Nugent, K.A.; /Melbourne U.; Weckert, E.; /DESY; Wang, T.; Zhu, D.; Wu, B.; Graves, C.; Scherz, A.; Turner, J.J.; Schlotter, W.F.; /SLAC /LERMA, Ivry /Zurich, ETH /LBL, Berkeley /ANL, APS /Argonne /SLAC /LLNL, Livermore /Latrobe U. /SLAC /SLAC /European XFEL, Hamburg /SLAC /Hamburg U.

    2012-06-06

    Measurements of the spatial and temporal coherence of single, femtosecond x-ray pulses generated by the first hard x-ray free-electron laser, the Linac Coherent Light Source, are presented. Single-shot measurements were performed at 780 eV x-ray photon energy using apertures containing double pinholes in 'diffract-and-destroy' mode. We determined a coherence length of 17 {micro}m in the vertical direction, which is approximately the size of the focused Linac Coherent Light Source beam in the same direction. The analysis of the diffraction patterns produced by the pinholes with the largest separation yields an estimate of the temporal coherence time of 0.55 fs. We find that the total degree of transverse coherence is 56% and that the x-ray pulses are adequately described by two transverse coherent modes in each direction. This leads us to the conclusion that 78% of the total power is contained in the dominant mode.

  6. A hot-spare injector for the APS linac.

    SciTech Connect (OSTI)

    Lewellen, J. W.

    1999-04-13

    Last year a second-generation SSRL-type thermionic cathode rf gun was installed in the Advanced Photon Source (APS) linac. This gun (referred to as ''gun2'') has been successfully commissioned and now serves as the main injector for the APS linac, essentially replacing the Koontz-type DC gun. To help ensure injector availability, particularly with the advent of top-up mode operation at the APS, a second thermionic-cathode rf gun will be installed in the APS linac to act as a hot-spare beam source. The hot-spare installation includes several unique design features, including a deep-orbit Panofsky-style alpha magnet. Details of the hot-spare beamline design and projected performance are presented, along with some plans for future performance upgrades.

  7. Coherent electron cooling demonstration experiment

    SciTech Connect (OSTI)

    Litvinenko, V.N.; Belomestnykh, S.; Ben-Zvi, I.; Brutus, J.C.; Fedotov, A.; Hao, Y.; Kayran, D.; Mahler, G.; Marusic, A.; Meng, W.; McIntyre, G.; Minty, M.; Ptitsyn, V.; Pinayev, I.; Rao, T.; Roser, T.; Sheehy, B.; Tepikian, S.; Than, R.; Trbojevic, D.; Tuozzolo, J.; Wang, G.; Yakimenko, V.; Hutton, A.; Krafft, G.; Poelker, M.; Rimmer, R.; Bruhwiler, D.; Abell, D.T.; Nieter, C.; Ranjbar, V.; Schwartz, B.; Kholopov M.; Shevchenko, O.; McIntosh, P.; Wheelhouse, A.

    2011-09-04

    Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron-hadron and electron-hadron colliders. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using SRF linac. In this paper, we describe the setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC. We plan to complete the program in five years. During first two years we will build coherent electron cooler in IP2 of RHIC. In parallel we will develop complete package of computer simulation tools for the start-to-end simulation predicting exact performance of a CeC. The later activity will be the core of Tech X involvement into the project. We will use these tools to predict the performance of our CeC device. The experimental demonstration of the CeC will be undertaken in years three to five of the project. The goal of this experiment is to demonstrate the cooling of ion beam and to compare its measured performance with predictions made by us prior to the experiments.

  8. Coherent Averaging

    E-Print Network [OSTI]

    Julien M. E. Fraïsse; Daniel Braun

    2015-04-13

    We investigate in detail a recently introduced "coherent averaging scheme" in terms of its usefulness for achieving Heisenberg limited sensitivity in the measurement of different parameters. In the scheme, $N$ quantum probes in a product state interact with a quantum bus. Instead of measuring the probes directly and then averaging as in classical averaging, one measures the quantum bus or the entire system and tries to estimate the parameters from these measurement results. Combining analytical results from perturbation theory and an exactly solvable dephasing model with numerical simulations, we draw a detailed picture of the scaling of the best achievable sensitivity with $N$, the dependence on the initial state, the interaction strength, the part of the system measured, and the parameter under investigation.

  9. 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

    2009-09-01

    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.

  10. Longitudinal emittance oscillation in a superconducting drift tube linac

    SciTech Connect (OSTI)

    Kim, J.W.; Shepard, K.W.

    1995-07-01

    In drift tube linacs a beam energy spread results form the finite beam size. Radial variation of the axial accelerating field induces a beam energy spread, which, in general, will accumulate as the beam passes through successive drift tubes. This paper shows that under some conditions of periodic transverse focusing and longitudinal phase focusing, the correlation between the longitudinal and transverse motion can be used to correct the energy spread. The process of achieving such a correction is first described in a simplified situation, and then demonstrated for a particular tuning using a ray-tracing program which models a low velocity and low charge state linac designed for radioactive ion beams.

  11. Coherence recycling, collective operation, and coherence induced reversibility in quantum heat engines

    E-Print Network [OSTI]

    Raam Uzdin

    2015-09-21

    Abstract When quantum heat engines or refrigerators operate in the over-thermalization regime, quantum effects are not expected as the thermal baths eliminates all coherences. In this work we show that even in this seemingly non-quantum regime, it is possible to harvest coherence before it is erased, and obtain non classical effects. While the engine is not affected by the coherence harvesting, the extracted coherence can be used to cool external particles and reduce their entropy (the energy of the auxiliary particles is not modified). On top of cooling the extracted coherence can activate passive states. Coherence extraction also has an impact on the basic theory of heat machines. With coherence extraction, the standard expression for the total entropy production -Qc/Tc-Qh/Th is replaced by a simple relative entropy expression, that is orders of magnitude smaller in the regime of interest. Consequently, coherence extraction enables reversibility that is otherwise impossible. In addition, we present a collective engine operation scheme where coherence is recycled and shared between engines. This leads to an interesting performance boost where the total power scales quadratically with the number of engines, rather than linearly. Finally, a scheme for resource accounting is presented. It is demonstrated that coherence extraction and coherence injection extend the scope of known quantum thermal machines and add new modes of operation.

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

    SciTech Connect (OSTI)

    Tennant, Christopher D.; Douglas, David R.; Li, Rui; Tsai, C.-Y.

    2014-12-01

    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.

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

    SciTech Connect (OSTI)

    Oborn, B. M.; Kolling, S.; Metcalfe, P. E.; Crozier, S.; Litzenberg, D. W.; Keall, P. J.

    2014-05-15

    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.

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

    SciTech Connect (OSTI)

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

    2012-07-03

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

  15. Design and operation of the LBL heavy ion RFQ linac

    SciTech Connect (OSTI)

    Gouch, R.A.

    1984-05-01

    LBL has designed and tested a heavy ion RFQ linac for ions in the mass range of 1 to 40. Designed as part of a preinjector package for synchrotron applications, it is a low duty factor device, operating at 200 MHz with maximum surface fields as high as 28 MV/meter. It is a loop-driven, four vane structure employing several innovative design concepts. These include an exit matcher section, to ensure efficient capture by a following Alvarez linac; advanced mechanical design features, to ensure accurate positioning of the vane pole-tips; and vane coupling rings, to ensure field stabilization and balance. This RFQ has been used on a test bench to accelerate a variety of ions as heavy as silicon, with charge to mass ratios as low as 1/7. Results of the initial operation show that the structure meets all of the design performance criteria, and that it holds promise for a long lifetime of simple and reliable service. This RFQ linac will soon be incorporated into the Bevatron operations program as part of th 200 MHz injector upgrade. A further application of this same RFQ design is in the dedicated Heavy Ion Medical Accelerator presently under study at LBL. Details of the design, construction and testing of the RFQ linac are given.

  16. 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

    2015-04-21

    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.

  17. 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; European XFEL, Hamburg; Minitti, Michael P.; Mitra, Ankush; Moeller, Stefan; Rowen, Michael; Schlotter, William F.; et al

    2015-04-02

    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.

  18. The X-ray Pump–Probe instrument at the Linac Coherent Light Source

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

    Chollet, Matthieu; Alonso-Mori, Roberto; Cammarata, Marco; Damiani, Daniel; Defever, Jim; Delor, James T.; Feng, Yiping; Glownia, James M.; Langton, J. Brian; Nelson, Silke; et al

    2015-04-21

    The X-ray Pump–Probe instrument achieves femtosecond time-resolution with hard X-ray methods using a free-electron laser source. It covers a photon energy range of 4–24 keV. A femtosecond optical laser system is available across a broad spectrum of wavelengths for generating transient states of matter. The instrument is designed to emphasize versatility and the scientific goals encompass ultrafast physical, chemical and biological processes involved in the transformation of matter and transfer of energy at the atomic scale.

  19. Longitudinal dynamics of twin electron bunches in the Linac Coherent Light

    Office of Scientific and Technical Information (OSTI)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journalspectroscopy ofArticle) | SciTechPrinciplesstromal/stem cells

  20. Photon-in photon-out hard X-ray spectroscopy at the Linac Coherent Light

    Office of Scientific and Technical Information (OSTI)

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  1. Photon-in photon-out hard X-ray spectroscopy at the Linac Coherent Light

    Office of Scientific and Technical Information (OSTI)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeeding accessusers' guide. V1.0.0.Report) |Article) |kineticsSource

  2. The Linac Coherent Light Source (Journal Article) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

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  3. The Linac Coherent Light Source (Journal Article) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

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

    Office of Scientific and Technical Information (OSTI)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)FeedbackProperties ofThe MaximumReport) |SciTechSample from the

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

    Office of Scientific and Technical Information (OSTI)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)FeedbackProperties ofThe MaximumReport) |SciTechSample from the(Journal

  6. The X-ray correlation spectroscopy instrument at the Linac Coherent Light

    Office of Scientific and Technical Information (OSTI)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)FeedbackProperties ofThe MaximumReport)elastase-2;SciTechSource (Journal

  7. The X-ray correlation spectroscopy instrument at the Linac Coherent Light

    Office of Scientific and Technical Information (OSTI)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)FeedbackProperties ofThe MaximumReport)elastase-2;SciTechSource

  8. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPPfinalUnexpectedofWyko NT33004.DepartmentUsed

  9. Assessment of Alternative RF Linac Structures for APT

    SciTech Connect (OSTI)

    1997-03-26

    The APT program has been examining both normal and superconducting variants of the APT linac for the past two years. A decision on which of the two will be the selected technology will depend upon several considerations including the results of ongoing feasibility experiments, the performance and overall attractiveness of each of the design concepts, and an assessment of the system-level features of both alternatives. The primary objective of the Assessment of Alternative RF Linac Structures for APT study reported herein was to assess and compare, at the system-level, the performance, capital and life cycle costs, reliability/availability/maintainability (RAM) and manufacturing schedules of APT RF linear accelerators based upon both superconducting and normal conducting technologies. A secondary objective was to perform trade studies to explore opportunities for system optimization, technology substitution and alternative growth pathways and to identify sensitivities to design uncertainties.

  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)

    2014-02-15

    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. BEAM POSITION AND PHASE MONITORS FOR THE LANSCE LINAC

    SciTech Connect (OSTI)

    McCrady, Rodney C.; Gilpatrick, John D.; Power, John F.

    2011-01-01

    New beam-position and phase monitors are under development for the linac at the Los Alamos Neutron Science Center (LANSCE). Transducers have been designed and are being fabricated. We are considering many options for the electronic instrumentation to process the signals and provide position and phase data with the necessary precision and flexibility to serve the various required functions. We'll present the various options under consideration for instrumentation along with the advantages and shortcomings of these options.

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

    SciTech Connect (OSTI)

    Powers, Tom J.

    2014-12-01

    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.

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

    SciTech Connect (OSTI)

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

    2008-12-01

    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.

  14. 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...

  15. 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...

  16. Big Data Analaysis and Visualization: What Do LINACS and Tropical Storms Have In Common?

    E-Print Network [OSTI]

    Bethel, E. Wes

    2013-01-01

    Big Data Analaysis and Visualization: What Do LINACS andof California. BIG DATA ANALYSIS AND VISUALIZATION: WHAT DOproblems. INTRODUCTION Big data and its attendant

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

    E-Print Network [OSTI]

    De Santis, S

    2014-01-01

    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,

  18. 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; Deutsches Elektronen-Synchrotron, Hamburg; Seiboth, Frank; Feng, Yiping; Alonso-Mori, Roberto; Chollet, Matthieu; Lemke, Henrik T.; Sokaras, Dimosthenis; et al

    2015-04-14

    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.

  19. 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

    2014-06-01

    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.

  20. Novel LINAC II electrode geometry to create an axial field in a multipole ion guide.

    E-Print Network [OSTI]

    Ens, Werner

    and determines the upper m/z transmission limit. A conventional LINAC has a quadrupolar DC field distortion while like the LINAC(SCIEX) suffer from a reduced mass transmission window. A wide transmission window. The axial field is created by applying the same DC potential UL to all four T-shaped electrodes

  1. 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

  2. WE-D-BRD-01: Innovation in Radiation Therapy Delivery: Advanced Digital Linac Features

    SciTech Connect (OSTI)

    Xing, L; Wong, J; Li, R

    2014-06-15

    Last few years has witnessed significant advances in linac technology and therapeutic dose delivery method. Digital linacs equipped with high dose rate FFF beams have been clinically implemented in a number of hospitals. Gated VMAT is becoming increasingly popular in treating tumors affected by respiratory motion. This session is devoted to update the audience with these technical advances and to present our experience in clinically implementing the new linacs and dose delivery methods. Topics to be covered include, technical features of new generation of linacs from different vendors, dosimetric characteristics and clinical need for FFF-beam based IMRT and VMAT, respiration-gated VMAT, the concept and implementation of station parameter optimized radiation therapy (SPORT), beam level imaging and onboard image guidance tools. Emphasis will be on providing fundamental understanding of the new treatment delivery and image guidance strategies, control systems, and the associated dosimetric characteristics. Commissioning and acceptance experience on these new treatment delivery technologies will be reported. Clinical experience and challenges encountered during the process of implementation of the new treatment techniques and future applications of the systems will also be highlighted. Learning Objectives: Present background knowledge of emerging digital linacs and summarize their key geometric and dosimetric features. SPORT as an emerging radiation therapy modality specifically designed to take advantage of digital linacs. Discuss issues related to the acceptance and commissioning of the digital linacs and FFF beams. Describe clinical utility of the new generation of digital linacs and their future applications.

  3. 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

  4. Large dynamic range diagnostics for high current electron LINACs

    SciTech Connect (OSTI)

    Evtushenko, Pavel [JLAB

    2013-11-01

    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.

  5. 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)

    2013-11-07

    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.

  6. DIPOLE MODE DETUNING IN THE INJECTOR LINACS OF THE NLC.

    SciTech Connect (OSTI)

    Bane, K

    2004-09-29

    The injector linacs of the JLC/NLC project include the prelinac, the e{sup +} drive linac, the e{sup -} booster, and the e{sup +} booster. The first three will be S-band machines, the last one, an L-band machine. We have demonstrated that by using detuning alone in the accelerator structure design of these linacs we will have acceptable tolerances for emittance growth due to both injection jitter and structure misalignments, for both the nominal (2.8 ns) and alternate (1.4 ns) bunch spacings. For the L-band structure (a structure with 2{pi}/3 phase advance) we take a uniform distribution in synchronous dipole mode frequencies, with central frequency {bar f} = 2.05 GHz and width {Delta}{sub {delta}f} = 3%. For the S-band case our optimized structure (a 3{pi}/4 structure) has a trapezoidal dipole frequency distribution with f = 3.92 GHz, {Delta}{sub {delta}f} = 5.8%, and tilt parameter {alpha} = -.2. The central frequency and phase advance were chosen to put bunches early in the train on the zero crossing of the wake and, at the same time, keep the gradient optimized. We have shown that for random manufacturing errors with rms 5 {micro}m, (equivalent to 10{sup -4} error in synchronous frequency), the injection jitter tolerances are still acceptable. We have also shown that the structure alignment tolerances are loose, and that the cell-to-cell misalignment tolerance is {approx}> 40 {micro}m. Note that in this report we have considered only the effects of modes in the first dipole passband.

  7. Overview and Status Update of the Fermilab HINS Linac R&D Program

    SciTech Connect (OSTI)

    Webber, R.C.; Apollinari, G.; /Fermilab

    2009-05-01

    The Fermilab High Intensity Neutrino Source (HINS) Linac R&D program is continuing efforts to construct a first-of-a-kind superconducting H{sup -} linac. The goal of the HINS linac is to demonstrate, for the first time, acceleration of high intensity beam with superconducting spoke cavities, control of beam halo growth by use of solenoidal focusing optics throughout, and operation of many cavities from a single high-power RF source for acceleration of non-relativistic particles. The HINS effort is relevant to any future high brightness, high intensity linac and, in particular, to the linac proposed as part of Fermilab Project X to serve the next generation of neutrino physics and future muon storage ring/collider experiments. This paper updates the technical status of the various components being developed, built, and commissioned as a part of HINS and presents the outlook for the HINS program.

  8. Linac Alignment Algorithm: Analysis on 1-to-1 Steering

    SciTech Connect (OSTI)

    Sun, Yipeng; Adolphsen, Chris; /SLAC

    2011-08-19

    In a linear accelerator, it is important to achieve a good alignment between all of its components (such as quadrupoles, RF cavities, beam position monitors et al.), in order to better preserve the beam quality during acceleration. After the survey of the main linac components, there are several beam-based alignment (BBA) techniques to be applied, to further optimize the beam trajectory and calculate the corresponding steering magnets strength. Among these techniques the most simple and straightforward one is the one-to-one (1-to-1) steering technique, which steers the beam from quad center to center, and removes the betatron oscillation from quad focusing. For a future linear collider such as the International Linear Collider (ILC), the initial beam emittance is very small in the vertical plane (flat beam with {gamma}{epsilon}{sub y} = 20-40nm), which means the alignment requirement is very tight. In this note, we evaluate the emittance growth with one-to-one correction algorithm employed, both analytically and numerically. Then the ILC main linac accelerator is taken as an example to compare the vertical emittance growth after 1-to-1 steering, both from analytical formulae and multi-particle tracking simulation. It is demonstrated that the estimated emittance growth from the derived formulae agrees well with the results from numerical simulation, with and without acceleration, respectively.

  9. Study of beam loading and its compensation in the Compact Ultrafast Terahertz Free-Electron Laser injector linac

    SciTech Connect (OSTI)

    Lal, Shankar Pant, K. K.

    2014-12-15

    The RF properties of an accelerating structure, and the pulse structure and charge per bunch in the electron beam propagating through it are important parameters that determine the impact of beam loading in the structure. The injector linac of the Compact Ultrafast Terahertz Free-Electron Laser (CUTE-FEL) has been operated with two different pulse structures during initial commissioning experiments and the effect of beam loading on the accelerated electron beam parameters has been studied analytically for these two pulse structures. This paper discusses the analytical study of beam loading in a Standing Wave, Plane Wave Transformer linac employed in the CUTE-FEL setup, and a possible technique for its compensation for the electron beam parameters of the CUTE-FEL. A parametric study has been performed to study beam loading for different beam currents and to optimize injection time of the electron beam to compensate beam loading. Results from the parametric study have also been used to explain previously observed results from acceleration experiments in the CUTE-FEL setup.

  10. Coherence-induced entanglement 

    E-Print Network [OSTI]

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

    2005-01-01

    We show how atomic coherence can lead to entanglement between two thermal fields at a temperature T. We first show that the passage of a three-level atom in V configuration without coherence cannot create entanglement. However, if the excited states...

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

    SciTech Connect (OSTI)

    Ratner, Daniel; /Stanford U. /SLAC

    2012-05-25

    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.

  12. Ultrafast X-Ray Coherent Control

    SciTech Connect (OSTI)

    Reis, David

    2009-05-01

    This main purpose of this grant was to develop the nascent #12;eld of ultrafast x-ray science using accelerator-based sources, and originally developed from an idea that a laser could modulate the di#11;racting properties of a x-ray di#11;racting crystal on a fast enough time scale to switch out in time a shorter slice from the already short x-ray pulses from a synchrotron. The research was carried out primarily at the Advanced Photon Source (APS) sector 7 at Argonne National Laboratory and the Sub-Picosecond Pulse Source (SPPS) at SLAC; in anticipation of the Linac Coherent Light Source (LCLS) x-ray free electron laser that became operational in 2009 at SLAC (all National User Facilities operated by BES). The research centered on the generation, control and measurement of atomic-scale dynamics in atomic, molecular optical and condensed matter systems with temporal and spatial resolution . It helped develop the ultrafast physics, techniques and scienti#12;c case for using the unprecedented characteristics of the LCLS. The project has been very successful with results have been disseminated widely and in top journals, have been well cited in the #12;eld, and have laid the foundation for many experiments being performed on the LCLS, the world's #12;rst hard x-ray free electron laser.

  13. PULSED-FOCUSING RECIRCULATING LINACS FOR MUON ACCELERATION

    SciTech Connect (OSTI)

    Johnson, Rolland PAUL

    2014-12-31

    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.

  14. 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.

    2007-06-25

    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.

  15. TAC Proposal for Fundamental and Applied Research: Linac-Ring Type Phi-Factory

    E-Print Network [OSTI]

    O. Yavas; A. K. Ciftci; S. Sultansoy

    2000-05-24

    Main parameters of linac-ring type $phi$-factory proposed as the part of the Turkic Accelerator Complex (TAC) in the framework of ATAM Science Sity Project are discussed. Two sets of parameters, corresponding to E=130(260) MeV for electron linac and E=2000(1000) MeV positron ring, are considered. It is swoun that, in principle, L=10^(34)cm^(-2)s^(-1) can be achieved, which is more than an order exceeds the design luminosity of the DA$Phi$NE. Parameters of the FEL based on electron linac and synchrotron radiation sources based on the positron ring are estimated.

  16. THE SNS VACUUM CONTROL SYSTEM UPGRADE FOR THE SUPERCONDUCTING LINAC

    SciTech Connect (OSTI)

    Williams, Derrick C [ORNL] [ORNL

    2009-01-01

    The superconducting linac of the Spallation Neutron Source (SNS) has 23 cryomodules whose vacuum system is monitored and controlled by custom built hardware. The original control hardware was provided by Thomas Jefferson National Accelerator Facility (JLab) and contained a variety of custom boards utilizing integrated circuits to perform logic. The need for control logic changes, a desire to increase maintainability, and a desire to increase flexibility to adapt for the future has led to a Programmable Logic Controller (PLC) based upgrade. This paper provides an overview of the commercial off-the-shelf (COTS) hardware being used in the superconducting vacuum control system. Details of the design and challenges to convert a control system during small windows of maintenance periods without disrupting beam operation will be covered in this paper.

  17. Coherence-induced entanglement 

    E-Print Network [OSTI]

    Xiong, Han

    2006-08-16

    Coherence and entanglement are the two key concepts that distinguish quantum mechanics from classical mechanics. Many novel phenomena occuring in the quantum world are due to these two Â?physical quantitiesÂ?. They also play essential roles...

  18. Beam energy spread in FERMI@elettra gun and linac induced by intrabeam scattering

    E-Print Network [OSTI]

    Zholents, Alexander A

    2008-01-01

    spread in FERMI@elettra gun and linac induced by intrabeamcathode area in the electron guns know in the literature asmost visible within the electron gun where the electron beam

  19. Beam Dynamics Studies for the First Muon Linac of the Neutrino Factory

    SciTech Connect (OSTI)

    C. Bontoiu,M. Aslaninejad,J. Pozimski,Alex Bogacz

    2010-05-01

    Within the Neutrino Factory Project the muon acceleration process involves a complex chain of accelerators including a (single-pass) linac, two recirculating linacs and an FFAG. The linac consists of RF cavities and iron shielded solenoids for transverse focusing and has been previously designed relying on idealized field models. However, to predict accurately the transport and acceleration of a high emittance 30 cm wide beam with 10 % energy spread requires detailed knowledge of fringe field distributions. This article presents results of the front-to-end tracking of the muon beam through numerically simulated realistic field distributions for the shielded solenoids and the RF fields. Real and phase space evolution of the beam has been studied along the linac and the results are presented and discussed.

  20. The Potential of the Linac-Ring Type Colliders for Particle and Nuclear Physics

    E-Print Network [OSTI]

    A. K. Ciftci; E. Recepoglu; S. Sultansoy; O. Yavas; M. Yilmaz

    2003-10-02

    Linac-ring type colliders will open new windows for both energy frontier and particle factories. Concerning the first direction, these machines seem to be a sole way to TeV scale in lepton-hadron collisison at constituent level. An essential advantage of the linac-ring type lepton-hadron colliders is the possibility of the construction of gamma-p, gamma-A and FELgamma-A colliders based on them. Today, eRHIC, THERA (TESLA on HERA)and Linac*LHC can be considered as realistic candidates for future lepton-hadron and photon hadron colliders. When it comes to factories, one can reach essentially higher luminosities comparing to standard ring-ring type machines. For example, L=10^34 cm^-2 s^-1 can be achieved for phi and charm-tau factories. In this presentation we briefly discuss the parameters and physics search potential of the linac-ring type machines.

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

    E-Print Network [OSTI]

    Faltens, A.

    2010-01-01

    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

  2. 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.

    2012-12-21

    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.

  3. SAR image effects on coherence and coherence estimation.

    SciTech Connect (OSTI)

    Bickel, Douglas Lloyd

    2014-01-01

    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.

  4. 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; Doleans, Marc; Kim, Sang-Ho

    2013-01-01

    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.

  5. Sandia Energy - Spontaneous Coherence and Spin Texture

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

    Spontaneous Coherence and Spin Texture Home Energy Research EFRCs Solid-State Lighting Science EFRC Spontaneous Coherence and Spin Texture Spontaneous Coherence and Spin...

  6. First MR images obtained during megavoltage photon irradiation from a prototype integrated linac-MR system

    SciTech Connect (OSTI)

    Fallone, B. G.; Murray, B.; Rathee, S.; Stanescu, T.; Steciw, S.; Vidakovic, S.; Blosser, E.; Tymofichuk, D. [Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

    2009-06-15

    The authors report the first magnetic resonance (MR) images produced by their prototype MR system integrated with a radiation therapy source. The prototype consists of a 6 MV linac mounted onto the open end of a biplanar 0.2 T permanent MR system which has 27.9 cm pole-to-pole opening with flat gradients (40 mT/m) running under a TMX NRC console. The distance from the magnet isocenter to the linac target is 80 cm. The authors' design has resolved the mutual interferences between the two devices such that the MR magnetic field does not interfere with the trajectory of the electron in the linac waveguide, and the radiofrequency (RF) signals from each system do not interfere with the operation of the other system. Magnetic and RF shielding calculations were performed and confirmed with appropriate measurements. The prototype is currently on a fixed gantry; however, in the very near future, the linac and MR magnet will rotate in unison such that the linac is always aimed through the opening in the biplanar magnet. MR imaging was found to be fully operational during linac irradiation and proven by imaging a phantom with conventional gradient echo sequences. Except for small changes in SNR, MR images produced during irradiation were visually and quantitatively very similar to those taken with the linac turned off. This prototype system provides proof of concept that the design has decreased the mutual interferences sufficiently to allow the development of real-time MR-guided radiotherapy. Low field-strength systems (0.2-0.5 T) have been used clinically as diagnostic tools. The task of the linac-MR system is, however, to provide MR guidance to the radiotherapy beam. Therefore, the 0.2 T field strength would provide adequate image quality for this purpose and, with the addition of fast imaging techniques, has the potential to provide 4D soft-tissue visualization not presently available in image-guided radiotherapy systems. The authors' initial design incorporates a permanent magnet; however, other types of magnets and field strengths could also be incorporated. Usable MR images were obtained during linac irradiation from the linac-MR prototype. The authors' prototype design can be used as the functional starting point in developing real-time MR guidance offering soft-tissue contrast that can be coupled with tumor tracking for real-time adaptive radiotherapy.

  7. Painlevé IV Coherent States

    E-Print Network [OSTI]

    David Bermudez; Alonso Contreras-Astorga; David J. Fernández C

    2014-02-24

    A simple way to find solutions of the Painlev\\'e IV equation is by identifying Hamiltonian systems with third-order differential ladder operators. Some of these systems can be obtained by applying supersymmetric quantum mechanics (SUSY QM) to the harmonic oscillator. In this work, we will construct families of coherent states for such subset of SUSY partner Hamiltonians which are connected with the Painlev\\'e IV equation. First, these coherent states are built up as eigenstates of the annihilation operator, then as displaced versions of the extremal states, both involving the third-order ladder operators, and finally as extremal states which are also displaced but now using the so called linearized ladder operators. To each SUSY partner Hamiltonian corresponds two families of coherent states: one inside the infinite subspace associated with the isospectral part of the spectrum and another one in the finite subspace generated by the states created through the SUSY technique.

  8. Coherent soliton communication lines

    SciTech Connect (OSTI)

    Yushko, O. V. Redyuk, A. A.; Fedoruk, M. P.; Turitsyn, S. K.

    2014-11-15

    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.

  9. Design of the beryllium window for Brookhaven Linac Isotope Producer

    SciTech Connect (OSTI)

    Nayak, S.; Mapes, M.; Raparia, D.

    2015-11-01

    In the Brookhaven Linac Isotope Producer (BLIP) beam line, there were two Beryllium (Be) windows with an air gap to separate the high vacuum upstream side from low vacuum downstream side. There had been frequent window failures in the past which affected the machine productivity and increased the radiation dose received by worker due to unplanned maintenance. To improve the window life, design of Be window is reexamined. Detailed structural and thermal simulations are carried out on Be window for different design parameters and loading conditions to come up with better design to improve the window life. The new design removed the air gap and connect the both beam lines with a Be window in-between. The new design has multiple advantages such as 1) reduces the beam energy loss (because of one window with no air gap), 2) reduces air activation due to nuclear radiation and 3) increased the machine reliability as there is no direct pressure load during operation. For quick replacement of this window, an aluminum bellow coupled with load binder was designed. There hasn’t been a single window failure since the new design was implemented in 2012.

  10. Coherent states in quantum mechanics

    E-Print Network [OSTI]

    Rodrigues, R D L; Fernandes, D

    2001-01-01

    We present a review work on the coherent states is non-relativistic quantum mechanics analysing the quantum oscillators in the coherent states. The coherent states obtained via a displacement operator that act on the wave function of ground state of the oscillator and the connection with Quantum Optics which were implemented by Glauber have also been considered. A possible generalization to the construction of new coherent states it is point out.

  11. Quantum Coherence Engines

    E-Print Network [OSTI]

    Elias P. Gyftopoulos

    2007-06-20

    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.

  12. Coherent hybrid electromagnetic field imaging

    DOE Patents [OSTI]

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

    2008-08-26

    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.

  13. 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

    2015-05-28

    Quantum coherence is a key element in 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 upperbound 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.

  14. IRIDE White Book, An Interdisciplinary Research Infrastructure based on Dual Electron linacs&lasers

    E-Print Network [OSTI]

    D. Alesini; M. Alessandroni; M. P. Anania; S. Andreas; M. Angelone; A. Arcovito; F. Arnesano; M. Artioli; L. Avaldi; D. Babusci; A. Bacci; A. Balerna; S. Bartalucci; R. Bedogni; M. Bellaveglia; F. Bencivenga; M. Benfatto; S. Biedron; V. Bocci; M. Bolognesi; P. Bolognesi; R. Boni; R. Bonifacio; M. Boscolo; F. Boscherini; F. Bossi; F. Broggi; B. Buonomo; V. Calo'; D. Catone; M. Capogni; M. Capone; M. Castellano; A. Castoldi; L. Catani; G. Cavoto; N. Cherubini; G. Chirico; M. Cestelli-Guidi; E. Chiadroni; V. Chiarella; A. Cianchi; M. Cianci; R. Cimino; F. Ciocci; A. Clozza; M. Collini; G. Colo'; A. Compagno; G. Contini; M. Coreno; R. Cucini; C. Curceanu; S. Dabagov; E. Dainese; I. Davoli; G. Dattoli; L. De Caro; P. De Felice; S. Della Longa; G. Delle Monache; M. De Spirito; A. Di Cicco; C. Di Donato; D. Di Gioacchino; D. Di Giovenale; E. Di Palma; G. Di Pirro; A. Dodaro; A. Doria; U. Dosselli; A. Drago; R. Escribano; A. Esposito; R. Faccini; A. Ferrari; M. Ferrario; A. Filabozzi; D. Filippetto; F. Fiori; O. Frasciello; L. Fulgentini; G. P. Gallerano; A. Gallo; M. Gambaccini; C. Gatti; G. Gatti; P. Gauzzi; A. Ghigo; G. Ghiringhelli; L. Giannessi; G. Giardina; C. Giannini; F. Giorgianni; E. Giovenale; L. Gizzi; C. Guaraldo; C. Guazzoni; R. Gunnella; K. Hatada; S. Ivashyn; F. Jegerlehner; P. O. Keeffe; W. Kluge; A. Kupsc; M. Iannone; L. Labate; P. Levi Sandri; V. Lombardi; P. Londrillo; S. Loreti; M. Losacco; S. Lupi; A. Macchi; S. Magazu'; G. Mandaglio; A. Marcelli; G. Margutti; C. Mariani; P. Mariani; G. Marzo; C. Masciovecchio; P. Masjuan; M. Mattioli; G. Mazzitelli; N. P. Merenkov; P. Michelato; F. Migliardo; M. Migliorati; C. Milardi; E. Milotti; S. Milton; V. Minicozzi; S. Mobilio; S. Morante; D. Moricciani; A. Mostacci; V. Muccifora; F. Murtas; P. Musumeci; F. Nguyen; A. Orecchini; G. Organtini; P. L. Ottaviani; E. Pace; M. Paci; C. Pagani; S. Pagnutti; V. Palmieri; L. Palumbo; G. C. Panaccione; C. F. Papadopoulos; M. Papi; M. Passera; L. Pasquini; M. Pedio; A. Perrone; A. Petralia; C. Petrillo; V. Petrillo; M. Pillon; P. Pierini; A. Pietropaolo; A. D. Polosa; R. Pompili; J. Portoles; T. Prosperi; C. Quaresima; L. Quintieri; J. V. Rau; M. Reconditi; A. Ricci; R. Ricci; G. Ricciardi; E. Ripiccini; S. Romeo; C. Ronsivalle; N. Rosato; J. B. Rosenzweig; G. Rossi; A. A. Rossi; A. R. Rossi; F. Rossi; D. Russo; A. Sabatucci; E. Sabia; F. Sacchetti; S. Salducco; F. Sannibale; G. Sarri; T. Scopigno; L. Serafini; D. Sertore; O. Shekhovtsova; I. Spassovsky; T. Spadaro; B. Spataro; F. Spinozzi; A. Stecchi; F. Stellato; V. Surrenti; A. Tenore; A. Torre; L. Trentadue; S. Turchini; C. Vaccarezza; A. Vacchi; P. Valente; G. Venanzoni; S. Vescovi; F. Villa; G. Zanotti; N. Zema; M. Zobov

    2013-07-30

    This report describes the scientific aims and potentials as well as the preliminary technical design of IRIDE, an innovative tool for multi-disciplinary investigations in a wide field of scientific, technological and industrial applications. IRIDE will be a high intensity 'particle factory', based on a combination of a high duty cycle radio-frequency superconducting electron linac and of high energy lasers. Conceived to provide unique research possibilities for particle physics, for condensed matter physics, chemistry and material science, for structural biology and industrial applications, IRIDE will open completely new research possibilities and advance our knowledge in many branches of science and technology. IRIDE will contribute to open new avenues of discoveries and to address most important riddles: What does matter consist of? What is the structure of proteins that have a fundamental role in life processes? What can we learn from protein structure to improve the treatment of diseases and to design more efficient drugs? But also how does an electronic chip behave under the effect of radiations? How can the heat flow in a large heat exchanger be optimized? The scientific potential of IRIDE is far reaching and justifies the construction of such a large facility in Italy in synergy with the national research institutes and companies and in the framework of the European and international research. It will impact also on R&D work for ILC, FEL, and will be complementarity to other large scale accelerator projects. IRIDE is also intended to be realized in subsequent stages of development depending on the assigned priorities.

  15. Present and Future Optics Challenges at CHESS and for Proposed Energy Recovery Linac Source of Synchrotron Radiation

    E-Print Network [OSTI]

    Shen, Qun

    Present and Future Optics Challenges at CHESS and for Proposed Energy Recovery Linac Source-ray optics, energy-recovery linac, high brilliance 1. INTRODUCTION As one of the pioneer synchrotron in the area of high heat load and high x-ray flux optics [1-5] since the high critical-energy wigglers

  16. 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

    2012-07-01

    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.

  17. Conceptual study of high power proton linac for accelerator driven subcritical nuclear power system

    E-Print Network [OSTI]

    Yu Qi; Ouyang Hua Fu; Xu Tao Guang

    2001-01-01

    As a prior option of the next generation of energy source, the accelerator driven subcritical nuclear power system (ADS) can use efficiently the uranium and thorium resource, transmute the high-level long-lived radioactive wastes and raise nuclear safety. The ADS accelerator should provide the proton beam with tens megawatts. The superconducting linac is a good selection of ADS accelerator because of its high efficiency and low beam loss rate. The ADS accelerator presented by the consists of a 5 MeV radio-frequency quadrupole, a 100 MeV independently phased superconducting cavity linac and a 1 GeV elliptical superconducting cavity linac. The accelerating structures and main parameters are determined and the research and development plan is considered

  18. Beam loading compensation of traveling wave linacs through the time dependence of the rf drive

    SciTech Connect (OSTI)

    Towne N.; Rose J.

    2011-09-30

    Beam loading in traveling-wave linear accelerating structures leads to unacceptable spread of particle energies across an extended train of bunched particles due to beam-induced field and dispersion. Methods for modulating the rf power driving linacs are effective at reducing energy spread, but for general linacs do not have a clear analytic foundation. We report here methods for calculating how to modulate the rf drive in arbitrarily nonuniform traveling-wave linacs within the convective-transport (power-diffusion) model that results in no additional energy spread due to beam loading (but not dispersion). Varying group velocity, loss factor, and cell quality factor within a structure, and nonzero particle velocity, are handled.

  19. A Linac Simulation Code for Macro-Particles Tracking and Steering Algorithm Implementation

    SciTech Connect (OSTI)

    sun, yipeng

    2012-05-03

    In this paper, a linac simulation code written in Fortran90 is presented and several simulation examples are given. This code is optimized to implement linac alignment and steering algorithms, and evaluate the accelerator errors such as RF phase and acceleration gradient, quadrupole and BPM misalignment. It can track a single particle or a bunch of particles through normal linear accelerator elements such as quadrupole, RF cavity, dipole corrector and drift space. One-to-one steering algorithm and a global alignment (steering) algorithm are implemented in this code.

  20. Assisted distillation of quantum coherence

    E-Print Network [OSTI]

    Chitambar, E; Rana, S; Bera, M N; Adesso, G; Lewenstein, M

    2015-01-01

    We introduce and study the task of assisted coherence distillation. This task arises naturally in bipartite systems where both parties work together to generate the maximal possible coherence on one of the subsystems. Only incoherent operations are allowed on the target system while general local quantum operations are permitted on the other, an operational paradigm that we call local quantum-incoherent operations and classical communication (LQICC). We show that the asymptotic rate of assisted coherence distillation for pure states is equal to the coherence of assistance, a direct analog of the entanglement of assistance, whose properties we characterize. Our findings imply a novel interpretation of the von Neumann entropy: it quantifies the maximum amount of extra quantum coherence a system can gain when receiving assistance from a collaborative party. Our results are generalized to coherence localization in a multipartite setting and possible applications are discussed.

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

    E-Print Network [OSTI]

    Danon, Yaron

    1Mechanical, Aerospace and Nuclear Engineering nacThe Gaerttner Laboratory RPI LINAC Facility Nuclear Criticality Safety Program Conference April 27, 2011 #12;2Mechanical, Aerospace and Nuclear · Refurbishment/Upgrade Projects (Recent Future) · Resources at the Facility #12;3Mechanical, Aerospace

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

    SciTech Connect (OSTI)

    Ben-Zvi, Ilan

    2013-03-31

    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.

  3. 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

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

    E-Print Network [OSTI]

    Boyer, Edmond

    is dedicated to the engineering and realization of a prototype cryomodule of the high energy section cryomodule of the high energy section of the superconducting proton linac. A cryomodule is the basic building. The test cryomodule will be a prototypical module of the beta 0.5 section containing one single elliptical

  5. Quantum Coherence and Its Distribution

    E-Print Network [OSTI]

    Asutosh Kumar

    2015-08-04

    Quantum coherence is the yield of the superposition principle. Recently, it has been theorized as a quantum resource, and is the premise of quantum correlations in multipartite systems. However, coherence is degraded by environmental interactions. It is therefore natural to study the coherence content and its distribution in a multipartite quantum system. In this work, we show analytically as well as numerically the reciprocity between coherence and mixedness of a quantum state. It appears that this trade-off is a general feature rather being exotic. We also study the distribution of coherence in multipartite systems and prove several interesting results. Numerical investigation unravels the fact that the percent of quantum states satisfying the additivity relation of coherence increases with increasing number of parties, the rank of quantum state and raising the power of coherence measure under investigation. We also study distribution of coherence in X states. We further show that for Dicke states, while the normalized measures of coherence violate the additivity relation, the unnormalized ones do satisfy the same.

  6. Measuring Quantum Coherence with Entanglement

    E-Print Network [OSTI]

    Alexander Streltsov; Uttam Singh; Himadri Shekhar Dhar; Manabendra Nath Bera; Gerardo Adesso

    2015-06-18

    Quantum coherence is an essential ingredient in quantum information processing and plays a central role in emergent fields such as nanoscale thermodynamics and quantum biology. However, our understanding and quantitative characterization of coherence as an operational resource are still very limited. Here we show that any degree of coherence with respect to some reference basis can be converted to entanglement via incoherent operations. This finding allows us to define a novel general class of measures of coherence for a quantum system of arbitrary dimension, in terms of the maximum bipartite entanglement that can be generated via incoherent operations applied to the system and an incoherent ancilla. The resulting measures are proven to be valid coherence monotones satisfying all the requirements dictated by the resource theory of quantum coherence. We demonstrate the usefulness of our approach by proving that the fidelity-based geometric measure of coherence is a full convex coherence monotone, and deriving a closed formula for it on arbitrary single-qubit states. Our work provides a clear quantitative and operational connection between coherence and entanglement, two landmark manifestations of quantum theory and both key enablers for quantum technologies.

  7. Coherent bremsstrahlung in a bent crystal

    E-Print Network [OSTI]

    Bondarenco, M V

    2009-01-01

    At passage of an ultra-high-energy particle through a bent crystal coherent bremsstrahlung is emitted but with characteristic frequencies distributed continuously, in relation with the crystal bend profile. For practical crystals, such radiation can be calculated by the stationary phase approximation technique. The radiation spectrum averaged over the impact parameters is evaluated. Its characteristic feature is the presence of sharp breaks (or of the spectrum end-point) at photon energies proportional to frequencies of crystalline plane crossing at the edges of the crystal, but those features will smear out if the angular divergence of the beam is comparable to half the crystal bending angle.

  8. Effect of longitudinal magnetic fields on a simulated in-line 6 MV linac

    SciTech Connect (OSTI)

    St Aubin, J.; Santos, D. M.; Steciw, S.; Fallone, B. G. [Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

    2010-09-15

    Purpose: Linac-magnetic resonance (MR) systems have been proposed in order to achieve real-time image guided radiotherapy. The design of a new linac-MR system with the in-line 6 MV linac generating x-rays along the symmetry axis of an open MR imager is outlined. This new design allows for a greater MR field strength to achieve better quality images while reducing hot and cold spots in treatment planning. An investigation of linac's performance in the longitudinal fringe magnetic fields of the MR imager is given. Methods: The open MR imager fringe magnetic field was modeled using the analytic solution of the magnetic field generated from current carrying loops. The derived solution was matched to the magnetic fringe field isolines provided for a 0.5 T open MR imager through Monte Carlo optimization. The optimized field solution was then added to the previously validated 6 MV linac simulation to quantify linac's performance in the fringe magnetic field of a 0.5 T MR imager. To further the investigation, linac's performance in large fringe fields expected from other imagers was investigated through the addition of homogeneous longitudinal fields. Results: The Monte Carlo optimization of the analytic current loop solution provided good agreement with the magnetic fringe field isolines supplied by the manufacturer. The range of magnetic fields the linac is expected to experience when coupled to the 0.5 T MR imager was determined to be from 0.0022 to 0.011 T (as calculated at the electron gun cathode). The effect of the longitudinal magnetic field on the electron beam was observed to be only in the electron gun. The longitudinal field changed the electron gun optics, affecting beam characteristics, such as a slight increase in the injection current and beam diameter, and an increasingly nonlaminar transverse phase space. Although the target phase space showed little change in its energy spectrum from the altered injection phase space, a reduction in the target current and spatial distribution peak intensity was observed. Despite these changes, the target phase space had little effect on the depth dose curves or dose profiles calculated for a 40x40 cm{sup 2} field at 1.5 cm depth. At longitudinal fields larger than 0.012 T, a drastic reduction in the injection current from the electron gun was observed due to a large fraction of electrons striking the anode. This further reduced the target current, which reached a minimum of 28{+-}2 mA at 0.06 T. A slow increase in the injection and target currents was observed at fields larger than 0.06 T due to greater beam collimation in the anode beam tube. Conclusions: In an effort to achieve higher quality images and a reduction in hot and cold spots in the treatment plan, a parallel configuration linac-MR system is presented. The longitudinal magnetic fields of the MR imager caused large beam losses within the electron gun. These losses may be eliminated through a redesign of the electron gun optics incorporating a longitudinal magnetic field, or through magnetic shielding, which has already been proven successful for the transverse configuration.

  9. SU-E-T-119: Dosimetric and Mechanical Characteristics of Elekta Infinity LINAC with Agility MLC

    SciTech Connect (OSTI)

    Park, J; Xu, Q; Xue, J; Zhai, Y; An, L; Chen, Y [MD Anderson Cancer Center at Cooper, Camden, NJ (United States)

    2014-06-01

    Purpose: Elekta Infinity is the one of the latest generation LINAC with unique features. Two Infinity LINACs are recently commissioned at our institution. The dosimetric and mechanical characteristics of the machines are presented. Methods: Both Infinity LINACs with Agility MLC (160 leaves with 0.5 cm leaf width) are configured with five electron energies (6, 9, 12, 15, and 18 MeV) and two photon energies (6 and 15 MV). One machine has additional photon energy (10 MV). The commissioning was performed by following the manufacturer's specifications and AAPM TG recommendations. Beam data of both electron and photon beams are measured with scanning ion chambers and linear diode array. Machines are adjusted to have the dosimetrically equivalent characteristics. Results: The commissioning of mechanical and imaging system meets the tolerances by TG recommendations. The PDD{sub 10} of various field sizes for 6 and 15 MV shows < 0.5% difference between two machines. For each electron beams, R{sub 80} matches with < 0.4 mm difference. The symmetry and flatness agree within 0.8% and 0.9% differences for photon beams, respectively. For electron beams, the differences of the symmetry and flatness are within 1.2% and 0.8%, respectively. The mean inline penumbras for 6, 10, and 15 MV are respectively 5.1±0.24, 5.6±0.07, and 5.9±0.10 mm for 10x10 cm at 10 cm depth. The crossline penumbras are larger than inline penumbras by 2.2, 1.4, and 1.0 mm, respectively. The MLC transmission factor with interleaf leakage is 0.5 % for all photon energies. Conclusion: The dosimetric and mechanical characteristics of two Infinity LINACs show good agreements between them. Although the Elekta Infinity has been used in many institutions, the detailed characteristics of the machine have not been reported. This study provides invaluable information to understand the Infinity LINAC and to compare the quality of commissioning data for other LINACs.

  10. A photocathode rf gun design for a mm-wave linac-based FEL

    SciTech Connect (OSTI)

    Nassiri, A.; Berenc, T,; Foster, J.; Waldschmidt, G.; Zhou, J.

    1995-07-01

    In recent years, advances in the rf gun technology have made it possible to produce small beam emittances suitable for short period microundulators which take advantage of the low emittance beam to reduce the wavelength of FELs. At the Advanced Photon Source, we are studying the design of a compact 50-MeV superconducting mm-wave linac-based FEL for the production of short wavelengths ({approximately}300 nm) to carry out FEL demonstration experiments. The electron source considered for the linac is a 30- GHz, 3 1/2-cell {pi}-mode photocathode rf gun. For cold model rf measurements a 15-GHz prototype structure was fabricated. Here we report on the design, numerical modelling and the initial cold-model rf measurement results on the 15-GHz prototype structure.

  11. Demonstration of a laserwire emittance scanner for the CERN LINAC4 H- Beam

    E-Print Network [OSTI]

    Hofmann, T; Bosco, A; Gibson, S M; Roncarolo, F; Boorman, G; Raich, U; Bravin, E; Pozimski, J K; Letchford, A; Gabor, C

    2015-01-01

    A non-invasive, compact laserwire system has been developed to measure the transverse emittance of an H- beam and has been demonstrated at the new LINAC4 injector for the LHC at CERN. Light from a low power, pulsed laser source is conveyed via fibre to collide with the H- beam, a fraction of which is neutralized and then intercepted by a downstream diamond detector. Scanning the focused laser across the H- beam and measuring the distribution of the photo-neutralized particles enables the transverse emittance to be reconstructed. The vertical phase-space distribution of a 3 MeV beam during LINAC4 commissioning has been measured by the laserwire and verified with a conventional slit and grid method.

  12. Transient quantum coherent response to a partially coherent radiation field

    SciTech Connect (OSTI)

    Sadeq, Zaheen S.; Brumer, Paul

    2014-02-21

    The response of an arbitrary closed quantum system to a partially coherent electric field is investigated, with a focus on the transient coherences in the system. As a model we examine, both perturbatively and numerically, the coherences induced in a three level V system. Both rapid turn-on and pulsed turn-on effects are investigated. The effect of a long and incoherent pulse is also considered, demonstrating that during the pulse the system shows a coherent response which reduces after the pulse is over. Both the pulsed scenario and the thermally broadened CW case approach a mixed state in the long time limit, with rates dictated by the adjacent level spacings and the coherence time of the light, and via a mechanism that is distinctly different from traditional decoherence. These two excitation scenarios are also explored for a minimal “toy” model of the electronic levels in pigment protein complex PC645 by both a collisionally broadened CW laser and by a noisy pulse, where unexpectedly long transient coherence times are observed and explained. The significance of environmentally induced decoherence is noted.

  13. 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: Erno-Sajo@uml.edu; Cifter, F.; Sajo, E. E-mail: Erno-Sajo@uml.edu

    2014-02-15

    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.

  14. Mu2e Experiment at Fermilab: Calibration with Linac and Collimation System Grace Bluhma,c

    E-Print Network [OSTI]

    Gollin, George

    MeV electrons. Figure 2. Linac and collimation overview. II. Method MATLAB3 is used to simulate with a circular hole 1 m in 3 D. Hanselman, et al., Mastering MATLAB 7, 2005. See also R. Pratap, Getting Started with MATLAB 7, 2006 4 A0 photoinjector parameters, http://www-ap.fnal.gov/A0PI/INJII_info.html #12;3 mittance

  15. Analysis of Lifetime Data for the Linac 201 MHz Power Amplifiers

    SciTech Connect (OSTI)

    Elliot McCrory and Robert C. Webber

    2002-07-09

    This document analyzes data on the lifetime of the 201-MHz triode power amplifier (PA) vacuum tube, model number 7835, used in the low-energy half of the Linac. We observe that a 7835 power amplifier vacuum tube has historically provided about one and one-third years service in the Linac. The lifetime of recently re-manufactured tubes is somewhat less, but it is not clear if this is because the manufacturer is ''loosing their touch,'' or because tubes cannot be effectively rebuilt after a certain number of times. Taking into account the expected tube lifetimes, the statistical fluctuations on this number, and the amount of time it takes for the manufacturer to make good tubes, we require about 14 tubes either operating, ready as good spares or being manufactured, in order to have sufficient spares to run the Linac. As a hedge against supplier drop out, we need to increase our inventory of good spare tubes by about three tubes per year for the next few years.

  16. Solid state power amplifier as 805 MHz master source for the LANSCE coupled-cavity linac

    SciTech Connect (OSTI)

    Lyles, J.; Davis, J.

    1998-12-31

    From 100 to 800 MeV, the Los Alamos Neutron Science Center (LANSCE) proton linac receives RF power from forty-four 1.25 MW klystrons at 805 Megahertz (MHz). A single master RF source provides a continuous high level phase reference signal which drives the klystrons along the 731 meter-long linac through a coaxial transmission line. A single point failure of this system can deenergize the entire coupled-cavity linac (CCL) RF plant. The authors replaced a physically large air-cooled tetrode amplifier with a compact water-cooled unit based on modular amplifier pallets developed at LANSCE. Each 600 Watt pallet utilizes eight push-pull bipolar power transistor pairs operated in class AB. Four of these can easily provide the 2000 watt reference carrier from the stable master RF source. A radial splitter and combiner parallels the modules. This amplifier has proven to be completely reliable after two years of operation without failure. A second unit was constructed and installed for redundancy, and the old tetrode system was removed in 1998. The compact packaging for cooling, DC power, impedance matching, RF interconnection, and power combining met the electrical and mechanical requirements. CRT display of individual collector currents and RF levels is made possible with built-in samplers and a VXI data acquisition unit.

  17. Coherent control of neutron interferometry

    E-Print Network [OSTI]

    Pushin, Dmitry A

    2007-01-01

    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. ...

  18. Atmospheric rivers as Lagrangian coherent structures

    E-Print Network [OSTI]

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

    2015-01-01

    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.

  19. EA-1087: Finding of No Significant Impact

    Broader source: Energy.gov [DOE]

    Proposed Induction Linac System Experiments in Building 51B at Lawrence Berkeley National Laboratory, Berkeley, California

  20. 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

    neutron transmission and scattering measurements in the energy range from 0.4 to 20 MeV. Filtered neutron, a multiplicity capture gamma detector, a neutron scattering array of liquid scintillator detectors and a large The Gaerttner LINAC Laboratory at RPI uses a 60 MeV electron LINAC as a pulsed neutron source. The neutrons

  1. PHASE I ENERGY RECOVERY LINAC AT CORNELL UNIVERSITY* I. Bazarov, S. Belomestnykh, D. Bilderback, S. Gray, S. Gruner, Y. Li, M. Liepe, H. Padamsee, V.

    E-Print Network [OSTI]

    Gruner, Sol M.

    components, heat losses in the cryogenic system, and energy recovery efficiency. Study of halo formationPHASE I ENERGY RECOVERY LINAC AT CORNELL UNIVERSITY* I. Bazarov, S. Belomestnykh, D. Bilderback, S on the energy recovery linac (ERL) concept [1, 2]. Such a source will exceed the brightness of third generation

  2. Completeness of coherent state subsystems

    E-Print Network [OSTI]

    Karlheinz Gröchenig; Antti Haimi; José Luis Romero

    2015-07-12

    We investigate the completeness of coherent states subsystems with respect to several classes of states on rational lattices. Our main results show that the phase-space shifts of every finite linear combination of Hermite functions with respect to a rational lattice are complete in L^2(R), thus generalizing a remark of von Neumann (and proved by Bargmann, Perelomov et al.). An analogous result is proven for windows that factor into certain rational functions and the Gaussian. The results are also interesting from a conceptual point of view since they show a vast difference between the completeness and the frame property of a discrete set of coherent states.

  3. Coherent states for quadratic Hamiltonians

    E-Print Network [OSTI]

    Alonso Contreras-Astorga; David J Fernandez C; Mercedes Velazquez

    2010-12-01

    The coherent states for a set of quadratic Hamiltonians in the trap regime are constructed. A matrix technique which allows to identify directly the creation and annihilation operators will be presented. Then, the coherent states as simultaneous eigenstates of the annihilation operators will be derived, and they are going to be compared with those attained through the displacement operator method. The corresponding wave function will be found, and a general procedure for obtaining several expected values involving the canonical operators in these states will be described. The results will be illustrated through the asymmetric Penning trap.

  4. Dipole Mode Deturning in the NLC Injector Linacs(LCC-0043)

    SciTech Connect (OSTI)

    Bane, K

    2004-04-13

    The injector linacs of the JLC/NLC project include the prelinac, the e{sup +} drive linac, the e{sup -} booster, and the e{sup +} booster. The first three will be S-band machines, the last one, an L-band machine. We have demonstrated that by using detuning alone in the accelerator structure design of these linacs we will have acceptable tolerances for emittance growth due to both injection jitter and structure misalignments, for both the nominal (2.8 ns) and alternate (1.4 ns) bunch spacings. For the L-band structure (a structure with 2{pi}/3 phase advance) we take a uniform distribution in synchronous dipole mode frequencies, with central frequency {bar {line_integral}} = 2.05 GHz and width {Delta}{sub {delta}{line_integral}} = 3%. For the S-band case our optimized structure ( a 3{pi}/4 structure) has a trapezoidal dipole frequency distribution with {bar {line_integral}} = 3.92 GHz, {Delta}{sub {delta}{line_integral}} = 5.8%, and tilt parameter {alpha} = -.2. The central frequency and phase advance were chosen to put bunches early in the train on the zero crossing of the wake and, at the same time, keep the gradient optimized. We have shown that for random manufacturing errors with rms 5 {micro}m, (equivalent to 10{sup -4} error in synchronous frequency), the injection jitter tolerances are still acceptable. We have also shown that the structure alignment tolerances are loose, and that the cell-to-cell misalignment tolerance is {approx}> 40 {micro}m. Note that in this report we have considered only the effects of modes in the first dipole passband.

  5. A 4 to 0.1 nm FEL Based on the SLAC Linac

    SciTech Connect (OSTI)

    Pellegrini, C.; /UCLA

    2012-06-05

    The author show that using existing electron gun technology and a high energy linac like the one at SLAC, it is possible to build a Free Electron Laser operating around the 4 nm water window. A modest improvement in the gun performance would further allow to extend the FEL to the 0.1 nm region. Such a system would produce radiation with a brightness many order of magnitude above that of any synchrotron radiation source, existing or under construction, with laser power in the multigawatt region and subpicosecond pulse length.

  6. Developments and Tests of a 700 MHz Cryomodule for the Superconducting Linac of MYRRHA

    E-Print Network [OSTI]

    Bouly, F; Bosotti, A; Pierini, P; El Yakoubi, M; Berthelot, S; Biarrotte, J-L; Joly, C; Lesrel, J; Rampnoux, E

    2013-01-01

    The MYRRHA projects aims at the construction of an Accelerator Driven System demonstrator. The criticality will be sustained by an external spallation neutron flux; produced thanks to a 600 MeV high intensity proton beam. This beam will be delivered by a superconducting linac which must fulfil very stringent reliability requirements. To carry out “real scale” reliability-oriented experiments a 700 MHz Cryomodule was developed. Several tests were performed to commission the experimental set-up. We review here the obtained results and the lessons learnt by operating this module, as well as the on-going developments.

  7. Design of the MYRRHA 17-600 MeV Superconducting Linac

    E-Print Network [OSTI]

    Biarrotte, J-L; Bouly, F; Carneiro, J-P; Vandeplassche, D

    2013-01-01

    The goal of the MYRRHA project is to demonstrate the technical feasibility of transmutation in a 100MWth Accelerator Driven System (ADS) by building a new flexible irradiation complex in Mol (Belgium). The MYRRHA facility requires a 600 MeV accelerator delivering a maximum proton flux of 4 mA in continuous operation, with an additional requirement for exceptional reliability. This paper will briefly describe the beam dynamics design of the main superconducting linac section which covers the 17 to 600 MeV energy range and requires enhanced fault-tolerance capabilities.

  8. Study on design of superconducting proton linac for accelerator driven subcritical nuclear power system

    E-Print Network [OSTI]

    Yu Qi; Xu Tao Guang

    2002-01-01

    As a prior option of the next generation of energy source, the accelerator driven subcritical nuclear power system (ADS) can use efficiently the uranium and thorium resource, transmute the high-level long-lived radioactive wastes and raise nuclear safety. The ADS accelerator should provide the proton beam with tens megawatts. The superconducting linac (SCL) is a good selection of ADS accelerator because of its high efficiency and low beam loss rate. It is constitute by a series of the superconducting accelerating cavities. The cavity geometry is determined by means of the electromagnetic field computation. The SCL main parameters are determined by the particle dynamics computation

  9. Lung dosimetry in a linac-MRI radiotherapy unit with a longitudinal magnetic field

    SciTech Connect (OSTI)

    Kirkby, C.; Murray, B.; Rathee, S.; Fallone, B. G. [Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, Department of Oncology, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, Department of Oncology and Department of Physics, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

    2010-09-15

    Purpose: There is interest in developing linac-MR systems for MRI-guided radiation therapy. To date, the designs for such linac-MR devices have been restricted to a transverse geometry where the static magnetic field is oriented perpendicular to the direction of the incident photon beam. This work extends possibilities in this field by proposing and examining by Monte Carlo simulations, a probable longitudinal configuration where the magnetic field is oriented in the same direction as the photon beam. Methods: The EGSnrc Monte Carlo (MC) radiation transport codes with algorithms implemented to account for the magnetic field deflection of charged particles were used to compare dose distributions for linac-MR systems in transverse and longitudinal geometries. Specifically, the responses to a 6 MV pencil photon beam incident on water and lung slabs were investigated for 1.5 and 3.0 T magnetic fields. Further a five field lung plan was simulated in the longitudinal and transverse geometries across a range of magnetic field strengths from 0.2 through 3.0 T. Results: In a longitudinal geometry, the magnetic field is shown to restrict the radial spread of secondary electrons to a small degree in water, but significantly in low density tissues such as lung in contrast to the lateral shift in dose distribution seen in the transverse geometry. These effects extend to the patient case, where the longitudinal configuration demonstrated dose distributions more tightly confined to the primary photon fields, which increased dose to the planning target volume (PTV), bettered dose homogeneity within a heterogeneous (in density) PTV, and reduced the tissue interface effects associated with the transverse geometry. Conclusions: Dosimetry issues observed in a transverse linac-MR geometry such as changes to the depth dose distribution and tissue interface effects were significantly reduced or eliminated in a longitudinal geometry on a representative lung plan. Further, an increase in dose to the PTV, resulting from the magnetic field confining electrons to the forward direction, shows potential for a reduction in dose to the surrounding tissues.

  10. Designs for a Linac-Ring LHeC (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing BacteriaConnectlaser-solid interactionCrystalDesigning aDesigns for a Linac-Ring

  11. 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 ...

  12. 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

  13. Grothendieck operations and coherence in categories

    E-Print Network [OSTI]

    2011-05-17

    Feb 27, 2009 ... applications to artificial intelligence. Joseph Lipman (Purdue University). Grothendieck ops, coherence in categories. February 27, 2009.

  14. Quantum Coherence of Steered states

    E-Print Network [OSTI]

    Xueyuan Hu; Antony Milne; Boyang Zhang; Heng Fan

    2015-08-07

    We introduce the maximal steered coherence for bipartite quantum systems. This is a measure that describes the extent to which quantum steering can remotely create coherence. When Alice and Bob share a composite quantum state $\\rho$, a local measurement by Alice can steer Bob's state; our proposed measure, $\\mathcal C(\\rho)$, is defined as the maximal coherence of Bob's steered state in the eigenbasis of the original reduced state $\\rho_B$, where the maximization is taken over all possible positive-operator valued measurements for Alice. We prove that $\\mathcal C$ vanishes only for states that are zero quantum discord for Bob ("classical" states). Although $\\mathcal C$ is invariant under local unitary operations, a trace-preserving channel performed by Bob can increase $\\mathcal C$ when applied to either classical or entangled states. For a two-qubit state, we find that Bob's channel can increase $\\mathcal C$ if and only if it is neither unital nor semi-classical, which coincides with the condition for increasing quantum discord. On the one hand, this result relates the increase of discord-like correlations to the power of quantum steering for coherence generation. On the other hand, the proposed quantity $\\mathcal C$ is distinct from discord and other existing measures of quantum correlation.

  15. Coherent state Quantization of quaternions

    E-Print Network [OSTI]

    B. Muraleetharan; K. Thirulogasanthar

    2015-10-07

    Parallel to the quantization of the complex plane, using the canonical coherent states of a right quaternionic Hilbert space, quaternion field of quaternionic quantum mechanics is quantized. Associated upper symbols, lower symbols and related quantities are analysed. Quaternionic version of the harmonic oscillator and Weyl-Heisenberg algebra are also obtained.

  16. The Structure of Partially Coherent Fields

    E-Print Network [OSTI]

    Visser, Taco D.

    and polarization" refers to a new formulation of the electromagnetic theory of optical coherence that has been used of electromagnetic fields on propagation; the fundamental results are reviewed by Wolf (2007b). The topi. Numerical Simulation of Partially Coherent Fields 324 10. Direct Applications of Coherence Theory 326

  17. Quantum coherent states in cosmology

    E-Print Network [OSTI]

    Houri Ziaeepour

    2015-02-15

    Coherent states consist of superposition of infinite number of particles and do not have a classical analogue. We study their evolution in a FLRW cosmology and show that only when full quantum corrections are considered, they may survive the expansion of the Universe and form a global condensate. This state of matter can be the origin of accelerating expansion of the Universe, generally called dark energy, and inflation in the early universe. Additionally, such a quantum pool may be the ultimate environment for decoherence at shorter distances. If dark energy is a quantum coherent state, its dominant contribution to the total energy of the Universe at present provides a low entropy state which may be necessary as an initial condition for a new Big Bang in the framework of bouncing cosmology models.

  18. Quantum learning of coherent states

    E-Print Network [OSTI]

    Gael Sentís; Madalin Guta; Gerardo Adesso

    2014-10-31

    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.

  19. WE-G-17A-09: Novel Magnetic Shielding Design for Inline and Perpendicular Integrated 6 MV Linac and 1.0 T MRI Systems

    SciTech Connect (OSTI)

    Li, X; Ma, B; Kuang, Y; Diao, X

    2014-06-15

    Purpose: The influence of fringe magnetic fields delivered by magnetic resonance imaging (MRI) on the beam generation and transportation in Linac is still a major challenge for the integration of linear accelerator and MRI (Linac-MRI). In this study, we investigated an optimal magnetic shielding design for Linac-MRI and further characterized the beam trajectory in electron gun. Methods: Both inline and perpendicular configurations were analyzed in this study. The configurations, comprising a Linac-MRI with a 100cm SAD and an open 1.0 T superconductive magnet, were simulated by the 3D finite element method (FEM). The steel shielding around the Linac was included in the 3D model, the thickness of which was varied from 1mm to 20mm, and magnetic field maps were acquired with and without additional shielding. The treatment beam trajectory in electron gun was evaluated using OPERA 3d SCALA with and without shielding cases. Results: When Linac was not shielded, the uniformity of diameter sphere volume (DSV) (30cm) was about 5 parts per million (ppm) and the fringe magnetic fields in electron gun were more than 0.3 T. With shielding, the magnetic fields in electron gun were reduced to less than 0.01 T. For the inline configuration, the radial magnetic fields in the Linac were about 0.02T. A cylinder steel shield used (5mm thick) altered the uniformity of DSV to 1000 ppm. For the perpendicular configuration, the Linac transverse magnetic fields were more than 0.3T, which altered the beam trajectory significantly. A 8mm-thick cylinder steel shield surrounding the Linac was used to compensate the output losses of Linac, which shifted the magnetic fields' uniformity of DSV to 400 ppm. Conclusion: For both configurations, the Linac shielding was used to ensure normal operation of the Linac. The effect of magnetic fields on the uniformity of DSV could be modulated by the shimming technique of the MRI magnet. NIH/NIGMS grant U54 GM104944, Lincy Endowed Assistant Professorship.

  20. Collective Dynamics and Coherent Diagnostics of Microbunched Relativistic Electron Beams

    E-Print Network [OSTI]

    Marinelli, Agostino

    2012-01-01

    x-ray diffraction pat- tern at the LCLS [1] (left image) andtransition radiation in the lcls linac. Proceedings of the1.1). Recent experiments at the LCLS include the imaging of

  1. Commissioning of the first drift tube linac module in the Ground Test Accelerator

    SciTech Connect (OSTI)

    Johnson, K.F.; Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Bowling, S.; Cole, R.; Connolly, R.; Denney, P.; Erickson, J.; Gilpatrick, J.D.; Ingalls, W.B.; Kersteins, D.; Kraus, R.; Lysenko, W.P.; McMurry, D.; Mottershead, C.T.; Power, J.; Rose, C.; Rusthoi, D.P.; Sandoval, D.P.; Schneider, J.D.; Smith, M.; Vaughn, G.; Wadlinger, E.A.; Weiss, R.; Yuan, V.

    1993-06-01

    The Ground Test Accelerator (GTA) has the objective of verifying much of the technology required for producing high-brightness, high-current H{sup {minus}} beams. GTA commissioning is staged to verify the beam-dynamics design of each major accelerator component as it is brought on-line. The major components are the 35-keV H{sup {minus}} injector, the 2.5-MeV radio-frequency quadrupole (RFQ), the intertank matching section (IMS), the 3.2 MeV first 2{beta}{lambda} drift tube linac (DTL-1) module, and the 24-MeV GTA with 10 DTL modules. Results from the DTL-1 beam experiments will be presented.

  2. Note: Electronic damping of microphonics in superconducting resonators of a continuous wave linac

    SciTech Connect (OSTI)

    Joshi, Gopal; Sahu, Bhuban Kumar; Agarwal, Vivek; Kumar, Girish

    2014-02-15

    The paper presents an implementation technique to damp the microphonics in superconducting resonators utilizing the coupling between the electromagnetic and the mechanical modes of a resonator. In the technique used the resonant frequency variations are fed back to modulate the field amplitude through a suitable transfer function. Of the two transfer functions used in the experiments, one emulates a derivative action and is placed in a negative feedback configuration. The other transfer function is essentially a parallel combination of second order low pass filters and is used in a positive feedback configuration. Experiments with the Quarter Wave resonators of IUAC, New Delhi linac demonstrate that the damping of some of the modes increases significantly with the introduction of this feedback leading to a reduction in power required for field stabilization and quieter operation of the RF control system.

  3. Medium Power 352 MHZ solid state pulsed RF amplifiers for the CERN LINAC4 Project

    E-Print Network [OSTI]

    Broere, J; Gómez Martínez, Y; Rossi, M

    2011-01-01

    Economic, modular and highly linear pulsed RF amplifiers have recently been developed to be used for the three buncher cavities in the CERN Linac4. The amplifiers are water-cooled and can provide up to 33 kW pulsed RF Power, 1.5 ms pulse length and 50 Hz repetition rate. Furthermore a 60 kW unit is under construction to provide the required RF Power for the debuncher cavity. The concept is based on 1.2 kW RF power modules using the latest 6th generation LDMOS technology. For integration into the CERN control environment the amplifiers have an internal industrial controller, which will provide easy control and extended diagnostic functions. This paper describes the construction, performance, including linearity, phase stability and EMC compliance tests

  4. Beam Based HOM Analysis of Accelerating Structures at the TESLA Test Facility Linac

    SciTech Connect (OSTI)

    Wendt, M.; Schreiber, S.; Castro, P.; Gossel, A.; /DESY; Huning, M.; /Fermilab; Devanz, G.; Jablonka, M.; Magne, C.; Napoly, O.; /Saclay; Baboi, N.; /SLAC

    2005-08-09

    The beam emittance in future linear accelerators for high energy physics and SASE-FEL applications depends highly on the field performance in the accelerating structures, i.e. the damping of higher order modes (HOM). Besides theoretical and laboratory analysis, a beam based analysis technique was established [1] at the TESLA Test Facility (TTF) linac. It uses a charge modulated beam of variable modulation frequency to excite dipole modes. This causes a modulation of the transverse beam displacement, which is observed at a downstream BPM and associated with a direct analysis of the modes at the HOM-couplers. A brief introduction of eigenmodes of a resonator and the concept of the wake potential is given. Emphasis is put on beam instrumentation and signal analysis aspects, required for this beam based HOM measurement technique.

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

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

    Zhang, Zhen [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Tsinghua University, Beijing (China); Ding, Yuantao [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Marinelli, Agostino [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Huang, Zhirong [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)

    2015-03-01

    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.

  6. 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

    2015-03-01

    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

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

    SciTech Connect (OSTI)

    WANG,X.J.

    2001-01-22

    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.

  8. 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.

    2012-04-15

    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.

  9. Breast dosimetry in transverse and longitudinal field MRI-Linac radiotherapy systems

    SciTech Connect (OSTI)

    Mahdavi, S. R.; Esmaeeli, A. D.; Pouladian, M.; Sardari, D.; Bagheri, S.; Monfared, A. S.

    2015-02-15

    Purpose: In the framework of developing the integration of a MRI-Linac system, configurations of MRI-Linac units were simulated in order to improve the dose distribution in tangential breast radiotherapy using transverse and longitudinal magnetic field geometries of Lorentz force for both medial and lateral tangential fields. Methods: In this work, the GEANT4 Monte Carlo (MC) code was utilized to compare dose distributions in breast radiotherapy for Linac-MR systems in the transverse and longitudinal geometries within humanoid phantoms across a range of magnetic field strengths of 0.5 and 1.5 T. The dose increment due to scattering from the coils was investigated for both geometries as well. Computed tomography images of two patients were used for MC simulations. One patient had intact breast while the other was mastectomized. In the simulations, planning and methods of chest wall irradiation were similar to the actual clinical planning. Results: In a longitudinal geometry, the magnetic field is shown to restrict the lateral spread of secondary electrons to the lung, heart, and contralateral organs, which reduced the mean dose of the ipsilateral lung and heart by means of 17.2% and 6% at 1.5 T, respectively. The transverse configuration exhibits a significant increase in tissue interface effects, which increased dose buildup in the entrance regions of the lateral and medial tangent beams to the planning target volume (PTV) and improved dose homogeneity within the PTV. The improved relative average homogeneity index for two patients to the PTV at magnetic field strength of 1.5 T with respect to no magnetic field case evaluated was 11.79% and 34.45% in the LRBP and TRBP geometries, respectively. In both geometries, the simulations show significant mean dose reductions in the contralateral breast and chest wall skin, respectively, by a mean of 16.6% and 24.9% at 0.5 T and 17.2% and 28.1% at 1.5 T in the transverse geometry, and 10.56% and 14.6% at 0.5 T and 11.3% and 16.3% at 1.5 T in the longitudinal geometry. Considering the scattered photons which reflected from the coils, the average relative dose of each voxel is slightly increased by 0.53% and 0.32% in the LRBP and TRBP geometries, respectively. Conclusions: Orienting the B0 magnetic field parallel to the photon beam axis, LRBP geometry, tends to restrict the radial spread of secondary electrons which resulted in dose reduction to the lung. Dosimetry issues observed in both Linac-MR geometries, such as changes to the lateral dose distribution, significantly exhibited dose reduction in the contralateral organs on a representative breast plan. Further, the results show sharper edge dose volume histogram curves at 1.5 T for both geometries, especially in the LRBP configuration.

  10. Progress in cavity and cryomodule design for the Project X linac

    SciTech Connect (OSTI)

    Champion, M.; Barbanotti, S.; Foley, M.; Ginsburg, S.; Gonin, I; Grimm, C.; Kerby, J.; Nagaitsev, S.; Nicol, T.; Peterson, T.; Ristori, L.; /Fermilab

    2011-03-01

    The continuous wave 3 GeV Project X Linac requires the development of two families of cavities and cryomodules at 325 and 650 MHz. The baseline design calls for three types of superconducting single-spoke resonators at 325 MHz having betas of 0.11, 0.22, and 0.42 and two types of superconducting five-cell elliptical cavities having betas of 0.61 and 0.9. These cavities shall accelerate a 1 mA H- beam initially and must support eventual operation at 4 mA. The electromagnetic and mechanical designs of the cavities are in progress and acquisition of prototypes is planned. The heat load to the cryogenic system is up to 25 W per cavity in the 650 MHz section, thus segmentation of the cryogenic system is a major issue in the cryomodule design. Designs for the two families of cryomodules are underway.

  11. Precision X-Band Linac Technologies for Nuclear Photonics Gamma-Ray Sources

    SciTech Connect (OSTI)

    Hartemann, F V; Albert, F; Anderson, S G; Bayramian, A J; Cross, R R; Ebbers, C A; Gibson, D J; Houck, T L; Marsh, R A; Messerly, M J; Siders, C W; McNabb, D P; Barty, C J; Adolphsen, C E; Chu, T S; Jongewaard, E N; Tantawi, S G; Vlieks, A E; Wang, F; Wang, J W; Raubenheimer, T O; Ighigeanu, D; Toma, M; Cutoiu, D

    2011-08-31

    Nuclear photonics is an emerging field of research requiring new tools, including high spectral brightness, tunable gamma-ray sources; high photon energy, ultrahigh-resolution crystal spectrometers; and novel detectors. This presentation focuses on the precision linac technology required for Compton scattering gamma-ray light sources, and on the optimization of the laser and electron beam pulse format to achieve unprecedented spectral brightness. Within this context, high-gradient X-band technology will be shown to offer optimal performance in a compact package, when used in conjunction with the appropriate pulse format, and photocathode illumination and interaction laser technologies. The nascent field of nuclear photonics is enabled by the recent maturation of new technologies, including high-gradient X-band electron acceleration, robust fiber laser systems, and hyper-dispersion CPA. Recent work has been performed at LLNL to demonstrate isotope-specific detection of shielded materials via NRF using a tunable, quasi-monochromatic Compton scattering gamma-ray source operating between 0.2 MeV and 0.9 MeV photon energy. This technique is called Fluorescence Imaging in the Nuclear Domain with Energetic Radiation (or FINDER). This work has, among other things, demonstrated the detection of {sup 7}Li shielded by Pb, utilizing gamma rays generated by a linac-driven, laser-based Compton scattering gamma-ray source developed at LLNL. Within this context, a new facility is currently under construction at LLNL, with the goal of generating tunable {gamma}-rays in the 0.5-2.5 MeV photon energy range, at a repetition rate of 120 Hz, and with a peak brightness in the 10{sup 20} photons/(s x mm{sup 2} x mrad{sup 2} x 0.1% bw).

  12. Cohering Power of Unitary Operations and De-cohering of Quantum operations

    E-Print Network [OSTI]

    Zhengjun Xi; Mingliang Hu; Yongming Li; Heng Fan

    2015-10-22

    In this paper, we consider the cohering power of unitary operation, which is defined by the maximum coherence caused by an unitary operation acting on incoherent states. We obtain that the optimizations can be reduced to a simple discrete set that depends only on the fixed reference basis. Then, we investigate that the de-cohering power of quantum channel, which is defined by the maximum decay of coherence caused by quantum channel acting on the maximally coherent states. Based on the relative entropy, we discuss the cohering power of 1-qubit and 2-qubit unitary operations and the de-cohering power of quantum channel on 1-qubit system. Finally, we study the relation between the coherence and the discord via incoherent operation.

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

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

    still a mystery. Now, Mannella et al. have uncovered a parallel behavior in which CMR is driven by coherence involving composite "quasiparticles" known as polarons. The parallels...

  14. Spectral narrowing via quantum coherence 

    E-Print Network [OSTI]

    Mikhailov, Eugeniy E.; Sautenkov, Vladimir A.; Rostovtsev, Yuri V.; Zhang, Aihua; Zubairy, M. Suhail; Scully, Marlan O.; Welch, George R.

    2006-01-01

    narrowing via quantum coherence Eugeniy E. Mikhailov,1 Vladimir A. Sautenkov,1,2 Yuri V. Rostovtsev,1 Aihua Zhang,1 M. Suhail Zubairy,1,3 Marlan O. Scully,1,4 and George R. Welch1 1Department of Physics and Institute of Quantum Studies, Texas A...&M University, College Station, Texas 77843-4242, USA 2P. N. Lebedev Institute of Physics, 119991 Moscow, Russia 3Department of Electronics, Quaid-i-Azam University, Islamabad, Pakistan 4Department of Chemistry, Princeton University, Princeton, New Jersey...

  15. 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTIONRobertsdale, Alabama (Utility Company) JumpIowa: EnergyEnergyCoherent Inc Jump to: navigation,

  16. 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

    2002-02-25

    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.

  17. We propose UNITD, a unified hardware coherence framework that integrates translation coherence into the

    E-Print Network [OSTI]

    Lebeck, Alvin R.

    1 Abstract We propose UNITD, a unified hardware coherence framework that integrates translation. For caches that hold instructions or data, coherence is almost invariably maintained with an all-hardware cache coherence protocol. Hardware controllers at the caches coordinate amongst them- selves

  18. 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)

    2001-01-01

    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.

  19. Design and evaluation of a low-level RF control system analog/digital receiver for the ILC main Linacs

    SciTech Connect (OSTI)

    Mavric, Uros; Vidmar, Matjaz; Chase, Brian; /Fermilab

    2008-06-01

    The proposed RF distribution scheme for the two 15 km long ILC LINACs, uses one klystron to feed 26 superconducting RF cavities operating at 1.3 GHz. For a precise control of the vector sum of the signals coming from the SC cavities, the control system needs a high performance, low cost, reliable and modular multichannel receiver. At Fermilab we developed a 96 channel, 1.3 GHz analog/digital receiver for the ILC LINAC LLRF control system. In the paper we present a balanced design approach to the specifications of each receiver section, the design choices made to fulfill the goals and a description of the prototyped system. The design is tested by measuring standard performance parameters, such as noise figure, linearity and temperature sensitivity. Measurements show that the design meets the specifications and it is comparable to other similar systems developed at other laboratories, in terms of performance.

  20. Noise autocorrelation spectroscopy with coherent Raman scattering

    E-Print Network [OSTI]

    Loss, Daniel

    LETTERS Noise autocorrelation spectroscopy with coherent Raman scattering XIAOJI G. XU, STANISLAV O to noise. Here, we present a new approach to coherent Raman spectroscopy in which high resolution is achieved by means of deliberately introduced noise. The proposed method combines the efficiency

  1. Coherent state quantization of paragrassmann algebras

    E-Print Network [OSTI]

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

    2011-12-30

    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.

  2. 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

  3. Coherent State on SUq(2) Homogeneous Space

    E-Print Network [OSTI]

    N. Aizawa; R. Chakrabarti

    2009-06-30

    The generalized coherent states for quantum groups introduced by Jurco and Stovicek are studied for the simplest example SU_q(2) in full detail. It is shown that the normalized SU_q(2) coherent states enjoy the property of completeness, and allow a resolution of the unity. This feature is expected to play a key role in application of these coherent states in physical models. The homogeneous space of SU_q(2), i.e. the q-sphere of Podles, is reproduced in complex coordinates by using the coherent states. Differential calculus in the complex form on the homogeneous space is developed. High spin limit of the SU_q(2) coherent states is also discussed.

  4. SU-E-T-589: A Comparison of Field Size Dependence of Electron Depth Dose From Different Linacs

    SciTech Connect (OSTI)

    Kim, M; Zhu, T [University of Pennsylvania, Philadelphia, PA (United States)

    2014-06-01

    Purpose: For accurate dose calculation in electron beam therapy, it is important to know the percentage depth dose (PDD) for each beam. This can vary depending on the machine make and model and the field size. Three different linear accelerators were compared in this study. Methods: PDD data was collected for different output beam energies and different field sizes for three different linear accelerators (Siemens Primus, Varian 2300ix, Varian Truebeam). Data was compared for the same energy with the same field size to see if the PDD differed among manufacturers. Furthermore, PDD was compared for different field sizes of the same machine at the same energy. Results: For the same beam energy and the same field size, the PDD curves were comparable for the three linacs with variations within 13%. PDD curves for different field sizes and beam energies were compared to verify this result. At higher beam energies, the disagreement between PDD curves is more pronounced between different field sizes for all three of the linacs compared. Conclusions: For the same energy and field size, the variation between different machines was within 13%. For the same manufacturer (Varian Clinac 2300ix and Truebeam), the agreement is within 3% with a standard deviation of less than 2.5%. PDD curves for different field sizes for the same energy were also investigated for the three linacs.

  5. Laser Seeding Yields High-Power Coherent Terahertz Radiation

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

    Laser Seeding Yields High-Power Coherent Terahertz Radiation Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Wednesday, 25 April 2007 00:00 Researchers at...

  6. Laser Seeding Yields High-Power Coherent Terahertz Radiation

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

    Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Researchers at Berkeley Lab have been exploring the ways coherent synchrotron radiation (CSR) is generated in...

  7. Coherent Structures and Larval Transport in the California Current System

    E-Print Network [OSTI]

    Harrison, Cheryl S.

    2012-01-01

    track Lagrangian coherent structures. Proc. Natl. Acad. Sci.A. Shchepetkin. Equilibrium structure and dynamics of thetracks Lagrangian coherent structures (LCS) calculated from

  8. Coherent THz electromagnetic radiation emission as a shock wave...

    Office of Scientific and Technical Information (OSTI)

    Coherent THz electromagnetic radiation emission as a shock wave diagnostic and probe of ultrafast phase transformations Citation Details In-Document Search Title: Coherent THz...

  9. Scaling Law of Coherent Synchrotron Radiation in a Rectangular...

    Office of Scientific and Technical Information (OSTI)

    Scaling Law of Coherent Synchrotron Radiation in a Rectangular Chamber Citation Details In-Document Search Title: Scaling Law of Coherent Synchrotron Radiation in a Rectangular...

  10. The RF-System of the New Gsi High Current Linac Hsi

    E-Print Network [OSTI]

    Hutter, G; Hartmann, W; Kube, G; Pilz, M; Vinzenz, W

    2000-01-01

    The RF part of the new high current injector-linac HSI consists of five cavities with the new operating frequency of 36 MHz instead of 27 MHz of the removed Wideroe type injector. The calculated power requirements of the cavities including beam load in three structures were between 110 kW for a rebuncher and 1.75 MW pulse-power for the two IH-cavities. The beam load is up to 150 kW for the RFQ and up to 750 kW for the two drift tube tanks. An additional 36 MHz debuncher in the transfer line to the Synchrotron (SIS) will need 120 kW pulse power. We decided to fulfil these demands with amplifiers of only two power classes, namely three amplifiers with 2 MW and six amplifiers with 200 kW pulse output power. The latter ones are also used as drivers for the 2 MW stages. The 200 kW amplifiers were specified in detail by GSI and ordered in the industry. The three 2 MW final amplifiers were designed, constructed and built by GSI. The paper gives an overview of the complete RF system and the operating performance of a...

  11. Lorentz Coherence and the Proton Form Factor

    E-Print Network [OSTI]

    Young S. Kim

    2015-02-28

    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.

  12. Coherent Vector Meson Photoproduction with Nuclear Breakup in Relativistic Heavy Ion Collisions

    E-Print Network [OSTI]

    Anthony J. Baltz; Spencer R. Klein; Joakim Nystrand

    2002-05-10

    Relativistic heavy ions are copious sources of virtual photons. The large photon flux gives rise to a substantial photonuclear interaction probability at impact parameters where no hadronic interactions can occur. Multiple photonuclear interactions in a single collision are possible. In this letter, we use mutual Coulomb excitation of both nuclei as a tag for moderate impact parameter collisions. We calculate the cross section for coherent vector meson production accompanied by mutual excitation, and show that the median impact parameter is much smaller than for untagged production. The vector meson rapidity and transverse momentum distribution are very different from untagged exclusive vector meson production.

  13. 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

  14. Validating a token coherence protocol for scientific Fernandez-Pascual

    E-Print Network [OSTI]

    Acacio, Manuel

    Validating a token coherence protocol for scientific workloads Ricardo Fern´andez-Pascual r.fernandez

  15. The extraction of work from quantum coherence

    E-Print Network [OSTI]

    Kamil Korzekwa; Matteo Lostaglio; Jonathan Oppenheim; David Jennings

    2015-06-25

    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.

  16. GUEST EDITORIAL Coherent Multidimensional Optical Spectroscopy

    E-Print Network [OSTI]

    Mukamel, Shaul

    motions offering dramatically more information. In 1D spectroscopy, the linear electrical polarization to the picosecond, electronically off-resonant, coher- ent anti-Stokes Raman spectroscopy (CARS) measurements of

  17. Coherence properties of the radiation from FLASH

    E-Print Network [OSTI]

    Schneidmiller, E A

    2015-01-01

    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.

  18. Coherent regulation in yeast cell cycle network

    E-Print Network [OSTI]

    Nese Aral; Alkan Kabakcioglu

    2014-12-14

    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.

  19. Directoryless shared memory coherence using execution migration

    E-Print Network [OSTI]

    Lis, Mieszko

    We introduce the concept of deadlock-free migration-based coherent shared memory to the NUCA family of architectures. Migration-based architectures move threads among cores to guarantee sequential semantics in large ...

  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)

    2011-01-11

    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. 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)

    2012-02-21

    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.

  2. Adaptive characterization of coherent states

    E-Print Network [OSTI]

    Markku P. V. Stenberg; Kevin Pack; Frank K. Wilhelm

    2015-08-18

    We present methods for efficient characterization of an optical coherent state $|\\alpha\\rangle$. We choose measurement settings adaptively and stochastically, based on data while it is collected. Our algorithm divides the estimation in two distinct steps: (i) Before the first detection of vacuum state, the probability of choosing a measurement setting is proportional to detecting vacuum with the setting, which makes using too similar measurement settings twice unlikely and (ii) after the first detection of vacuum, we focus measurements in the region where vacuum is most likely to be detected. In step (i) [(ii)] the detection of vacuum (a photon) has a significantly larger effect on the shape of the posterior probability distribution of $\\alpha$. Compared to nonadaptive schemes, our method makes the number of measurement shots required to achieve certain level of accuracy smaller approximately by a factor proportional to the area describing the initial uncertainty of $\\alpha$ in phase space. While this algorithm is not directly robust against readout errors, we make it such by introducing repeated measurements in the step (i).

  3. Coherent Synchrotron Radiation for Laminar Flows

    E-Print Network [OSTI]

    Bjoern S. Schmekel; Richard V. E. Lovelace

    2006-11-16

    We investigate the effect of shear in the flow of charged particle equilibria that are unstable to the Coherent Synchrotron Radiation (CSR) instability. Shear may act to quench this instability because it acts to limit the size of the region with a fixed phase relation between emitters. The results are important for the understanding of astrophysical sources of coherent radiation where shear in the flow is likely.

  4. 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.

    2011-03-28

    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.

  5. The fourth generation, linac-ring type colliders, preons and so on

    E-Print Network [OSTI]

    Saleh Sultansoy

    2012-08-13

    Following a brief review of our contributions to the 2006 European PP Strategy, recent comments on several topics are presented. First of all, it is emphasized that only the simplest version of the fourth chiral generation, namely, minimal SM4 (mSM4) with only one Higgs doublet is in some tension with the recent LHC data on the Higgs boson search. This tension, which follows from the relative strengths of the H --> 4l and Higgs --> {\\gamma}{\\gamma} channels, can be naturally resolved if there is a mechanism to enhance the H-->{\\gamma}{\\gamma} width (although any charged and heavy particle could enhance the H-{\\gamma}-{\\gamma} loop, 2HDM can be given as an example). We then emphasize the possible role of the linac-ring type colliders, especially LHeC (QCD Exploder) and TAC super charm factory. The QCD Explorer will give opportunity to enlighten the origin of the 98.5% portion of the visible universe's mass. Especially the {\\gamma}-nucleus option seems to be very promising for QCD studies. The TAC super charm factory may provide opportunity to investigate the charm physics with statistics well above that of the dedicated runs at Super-B factories. Finally, it is argued that the history of particle physics (and, more generally, the history of the investigation of the fundamental ingredients of the matter), a large number of "fundamental" particles, an inflation of observable free parameters, and, especially, the mixing of "fundamental" fermions favor the idea of a new set of fundamental particles at a deeper level. These new particles can be formulated with the preonic or even pre-preonic models.

  6. Poster — Thur Eve — 57: Evaluation of laryngeal mucosal dose with conventional linac and TomoTherapy

    SciTech Connect (OSTI)

    Nusrat, H; Lekx, K; Eapen, L

    2014-08-15

    The purpose of this study was to examine whether or not underdosing occurs in the mucosal layer during treatment of glottis cancer. A larynx phantom was produced and regions at risk of recurrence due to suspected underdosing were identified and wells drilled into the phantom for flush placement of TLDs. Seven interest points were chosen. CT simulation was completed prior to the wells being drilled, and again afterwards with the TLD locations indicated using BBs. Treatment plans created for this investigation included: 3DCRT using Elekta-XiO (n=9) and VMAT created using Elekta-Monaco (n=9), both delivered on an Elekta linac; standard TomoTherapy plan (n=11) and a directionally blocked TomoTherapy plan to approximate a 3D-conformal approach (n=5). Imaging dose during TomoTherapy deliveries was accounted for. The average TLD result at each interest point was compared to the planned value using a paired t-test. There was no significant difference between the planned and measured 3DCRT dose (268.9 vs. 267.0 cGy, respectively; p>0.05). Similarly, the planned and measured TomoTherapy treatment did not show any significant differences (271.7 vs 269.7 cGy; p>0.05). In the blocked TomoTherapy plan, significant overdosing was seen (274.5 vs 294.9 cGy; p<0.05) and underdosing was not seen in the VMAT treatment (303.5 vs 321.8 cGy; p>0.05). Further investigation is ongoing to ensure appropriate normalization of results and to investigate the overdosing noted with the blocked TomoTherapy plan. Results from this study suggest that significant underdosing does not occur in the conventional treatment of early glottic cancer using 6MV photons.

  7. 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)

    2012-01-10

    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.

  8. 7 Ã… Resolution in Protein 2-Dimentional-Crystal X-Ray Diffraction at Linac

    Office of Scientific and Technical Information (OSTI)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563 LLNL Small-scaleCoherent Light Source (Journal Article) | SciTech

  9. A FOURTH ORDER RESONANCE OF A HIGH INTENSITY LINAC (Conference) | SciTech

    Office of Scientific and Technical Information (OSTI)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563 LLNL Small-scaleCoherent Light SourceAConnect Conference: A

  10. High-Fidelity Lagrangian Coherent Structures Analysis and DNS with Discontinuous-Galerkin Methods

    E-Print Network [OSTI]

    Nelson, Daniel Alan Wendell

    2015-01-01

    vi Lagrangian Coherent Structures with High-OrderCoherent Structures . . . . . . . . . . . . . . 7.3 FutureThree-Dimensional Lagrangian Coher- ent Structures with DG-

  11. Superconducting Resonators Development for the FRIB and ReA Linacs at MSU: Recent Achievements and Future Goals

    SciTech Connect (OSTI)

    Facco, A; Binkowski, J; Compton, C; Crisp, J L; Dubbs, L J; Elliot, K; Harle, L L; Hodek, M; Johnson, M J; Leitner, D; Leitner, M; Malloch, I M; Miller, S J; Oweiss, R; Popielarski, J; Popielarski, L; Saito, K; Wei, J; Wlodarczak, J; Xu, Y; Zhang, Y; Zheng, Z; Burrill, A; Davis, G K; Macha, K

    2012-07-01

    The superconducting driver and post-accelerator linacs of the FRIB project, the large scale radioactive beam facility under construction at MSU, require the construction of about 400 low-{beta} Quarter-wave (QWR) and Half-wave resonators (HWR) with four different optimum velocities. 1st and 2nd generation prototypes of {beta}{sub 0} = 0.041 and 0.085 QWRs and {beta}{sub 0} = 0.53 HWRs have been built and tested, and have more than fulfilled the FRIB and ReA design goals. The present cavity surface preparation at MSU allowed production of low-{beta} cavities nearly free from field emission. The first two cryostats of {beta}{sub 0} = 0.041 QWRs are now in operation in the ReA3 linac. A 3rd generation design of the FRIB resonators allowed to further improve the cavity parameters, reducing the peak magnetic field in operation and increasing the possible operation gradient, with consequent reduction of the number of required resonators. The construction of the cavities for FRIB, which includes three phases for each cavity type (development, pre-production and production runs) has started. Cavity design, construction, treatment and performance will be described and discussed.

  12. Design Concept of a Gamma-gamma Higgs Factory Driven by Thin Laser Targets and Energy Recovery Linacs

    SciTech Connect (OSTI)

    Zhang, Yuhong [JLAB

    2013-06-01

    A gamma-gamma collider has long been considered an option for a Higgs Factory. Such photon colliders usually rely on Compton back-scattering for generating high energy gamma photons and further Higgs bosons through gamma-gamma collisions. The presently existing proposals or design concepts all have chosen a very thick laser target (i.e., high laser photon intensity) for Compton scatterings. In this paper, we present a new design concept of a gamma-gamma collider utilizing a thin laser target (i.e., relatively low photon density), thus leading to a low electron to gamma photon conversion rate. This new concept eliminates most useless and harmful low energy soft gamma photons from multiple Compton scattering so the detector background is improved. It also greatly relaxes the requirement of the high peak power of the laser, a significant technical challenge. A high luminosity for such a gamma-gamma collider can be achieved through an increase of the bunch repetition rate and current of the driven electron beam. Further, multi-pass recirculating linac could greatly reduce the linac cost and energy recovery is required to reduce the needed RF power.

  13. Beam Line Design and Beam Physics Study of Energy Recovery Linac Free Electron Laser at Peking University

    SciTech Connect (OSTI)

    Guimei Wang

    2011-12-31

    Energy recovering linac (ERL) offers an attractive alternative for generating intense beams of charged particles by approaching the operational efficiency of a storage ring while maintaining the superior beam quality typical of a linear accelerator. In ERLs, the decelerated beam cancels the beam loading effects of the accelerated beam with high repetition rate. Therefore, ERLs can, in principle, accelerate very high average currents with only modest amounts of RF power. So the efficiency of RF power to beam is much higher. Furthermore, the energy of beam to dump is lower, so it will reduce dump radiation. With the successful experiments in large maximum-to-injection energy ratio up to 51:1 and high power FEL up to 14kW, the use of ERL, especially combining with superconducting RF technology, provides a potentially powerful new paradigm for generation of the charged particle beams used in MW FEL, synchrotron radiation sources, high-energy electron cooling devices and so on. The 3+1/2 DC-SC photo injector and two 9cell TESLA superconducting cavity for IR SASE FEL in PKU provides a good platform to achieve high average FEL with Energy Recovery. The work of this thesis is on Beam line design and Beam dynamics study of Energy Recovery Linac Free Electron Laser for Peking University. It is the upgrade of PKU facility, which is under construction. With ERL, this facility can work in CW mode, so it can operate high average beam current without RF power constraint in main linac and generate high average FEL power. Moreover, it provides a test facility to study the key technology in ERL. System parameters are optimized for PKU ERL-FEL. The oscillation FEL output power is studied with different bunch charge, transverse emittance, bunch length and energy spread. The theory of optimal RF power and Q{sub ext} with ERL and without ERL is analyzed and applied to PKU injector and linac including microphonic effect. pace charge effect in the injector and merger is studied for beam energy at ~5MeV. Simulation shows that in the 3+1/2 DC- C injector, there is a region the beam could be over focused by RF electromagnetic field and the transverse emittance in the transport line up to linac will increase instantly due to over focusing. In order to eliminate this effect on beam emittance, several solutions are investigated to avoid over focusing. This result is very important for beam loading experiment for low bunch charge operation. Meanwhile, different merger structures are compared in terms of error sensitivity and emittance increase with space charge effect. In recirculation beam line, a new symmetric 180{degree} arc structure is designed. It fulfills the achromatic condition and adjustable bunch compression. These two parameters are controlled by different Quads knob. With this novel structure, the recirculation lattice can achieve path length adjustment, bunch compression and decompression in a large range. With beamline error, the beam central orbit will deviate from the designed trajectory. An orbit correction system is optimized, which balances between cost and performance of orbit after correction at design level. Different methods are used to estimate its robustness. The BBU instability, especially multi-pass BBU imposed a potentially severe limitation to the average current that can be accelerated in an ERL. Simulation gives the harmful HOMs and predicts that the threshold average current in this machine is much higher than the possible operation current. This work is based on the existing facility in PKU, so it provides guidelines for the facility operation and upgrade in the future. The theoretical analysis of ERL requirement and FEL requirement on beam transport line and beam property paves the way for future ERL research.

  14. Store-operate-coherence-on-value

    DOE Patents [OSTI]

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

    2014-11-18

    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.

  15. Exciton coherence lifetimes from electronic structure

    E-Print Network [OSTI]

    Parkhill, John; Aspuru-Guzik, Alan

    2011-01-01

    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 ...

  16. Global coherence of dust density waves

    SciTech Connect (OSTI)

    Killer, Carsten; Melzer, André

    2014-06-15

    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.

  17. Coherent Synchrotron Radiation: Theory and Simulations.

    SciTech Connect (OSTI)

    Novokhatski, Alexander; /SLAC

    2012-03-29

    The physics of coherent synchrotron radiation (CSR) emitted by ultra-relativistic electron bunches, known since the last century, has become increasingly important with the development of high peak current free electron lasers and shorter bunch lengths in storage rings. Coherent radiation can be described as a low frequency part of the familiar synchrotron radiation in bending magnets. As this part is independent of the electron energy, the fields of different electrons of a short bunch can be in phase and the total power of the radiation will be quadratic with the number of electrons. Naturally the frequency spectrum of the longitudinal electron distribution in a bunch is of the same importance as the overall electron bunch length. The interest in the utilization of high power radiation from the terahertz and far infrared region in the field of chemical, physical and biological processes has led synchrotron radiation facilities to pay more attention to the production of coherent radiation. Several laboratories have proposed the construction of a facility wholly dedicated to terahertz production using the coherent radiation in bending magnets initiated by the longitudinal instabilities in the ring. Existing synchrotron radiation facilities also consider such a possibility among their future plans. There is a beautiful introduction to CSR in the 'ICFA Beam Dynamics Newsletter' N 35 (Editor C. Biscari). In this paper we recall the basic properties of CSR from the theory and what new effects, we can get from the precise simulations of the coherent radiation using numerical solutions of Maxwell's equations. In particular, transverse variation of the particle energy loss in a bunch, discovered in these simulations, explains the slice emittance growth in bending magnets of the bunch compressors and transverse de-coherence in undulators. CSR may play same the role as the effect of quantum fluctuations of synchrotron radiation in damping rings. It can limit the minimum achievable emittance in the synchrotron light sources for short bunches.

  18. Coherent bremsstrahlung in a bent crystal

    SciTech Connect (OSTI)

    Bondarenco, M. V.

    2010-05-15

    Coherent radiation spectrum from high energy e{sup {+-}}in a bent crystal with arbitrary curvature distribution along the longitudinal coordinate is evaluated, based on the stationary phase approximation. For a uniformly bent crystal a closed-form expression for the spectrum is derived. The spectrum features include a dip at its beginning and the sharp end, which may split into two breaks depending on the particle incidence angle. Estimates of nondipole radiation and multiple scattering effects are given. The value for the crystal bending angle at which the dipole coherent bremsstrahlung theory holds best appears to be {approx}10{sup -4} rad.

  19. Coherent photonuclear reactions for isotope transmutation

    E-Print Network [OSTI]

    H. Ejiri; S. Date

    2011-02-22

    Coherent photonuclear isotope transmutation (CPIT) produces exclusively radioactive isotopes (RIs) by coherent photonuclear reactions via E1 giant resonances. Photons to be used are medium energy photons produced by laser photons backscattered off GeV electrons. The cross sections are as large as 0.2 - 0.6 b, being independent of individual nuclides. A large fraction of photons is effectively used for the photonuclear reactions, while the scattered GeV electrons remain in the storage ring to be re-used. CPIT with medium energy photons provides specific/desired RIs with the high rate and the high density for nuclear science, molecular biology and for nuclear medicines.

  20. 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

  1. High speed handheld instrument for ophthalmic optical coherence tomography

    E-Print Network [OSTI]

    Lu, Chen David

    2013-01-01

    Optical coherence tomography (OCT) is a non-contact, high resolution biomedical imaging technique that uses low coherence interferometry to generate cross-sectional images of tissue. OCT has become a standard tool in ...

  2. Quantum Coherence Effects in Novel Quantum Optical Systems 

    E-Print Network [OSTI]

    Sete, Eyob Alebachew

    2012-10-19

    Optical response of an active medium can substantially be modified when coherent superpositions of states are excited, that is, when systems display quantum coherence and interference. This has led to fascinating applications in atomic and molecular...

  3. Characterization of coherent power of concatenation of quantum channels

    E-Print Network [OSTI]

    Kaifeng Bu; Lin Zhang; Junde Wu

    2015-10-27

    Quantum coherence, existing in quantum states, is a very important resource for design and implementation of quantum technologies. Quantum channels that can generate coherence is also an interesting topic and less known results about it. In this paper, we focus mainly on the coherent power of quantum channels and give a operational meaning to the coherent power. Then we characterize the coherent power of concatenation of quantum channels via that of individual channels. In addition, we also propose a new proper coherence measures which is subadditive. Thus coherence measure can be superadditive, additive, or subadditive, up to the specific problems investigated. At the end of this paper, we compare two different definitions of the coherent powers of quantum channels and find that they are not equivalent in general.

  4. 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.

  5. Simulation of a cascaded longitudinal space charge amplifier for broadband radiation production using a superconducting linac

    E-Print Network [OSTI]

    Halavanau, A

    2015-01-01

    Longitudinal space charge (LSC) effects are generally considered as harmful in free-electron lasers as they can seed unfavorable energy modulations that can result in density modulations with associated emittance dilution. It was pointed out, however, that such "micro-bunching instabilities'' could be potentially useful to support the generation of broadband coherent radiation. Therefore there has been an increasing interest in devising accelerator beam lines capable of controlling LSC induced density modulations. In the present paper we augment these previous investigations by combining a grid-less space charge algorithm with the popular particle-tracking program {\\sc elegant}. This high-fidelity model of the space charge is used to benchmark conventional LSC models. We finally employ the developed model to optimize the performance of a cascaded longitudinal space charge amplifier using beam parameters comparable to the ones achievable at Fermilab Accelerator Science \\& Technology (FAST) facility current...

  6. 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

    2008-03-01

    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.

  7. Asymmetric Multiclass Traffic Assignment: a coherent formulation

    E-Print Network [OSTI]

    Toint, Philippe

    of the asymmetric multiclass traffic assignment model are brought to light. A new formulation is presented, multiclass cost functions. A numerical calibration exercise for a car and truck class model concludes in the definition of coherent multiple value­of­time class and car­and­truck class models, and in the calibration

  8. Coherent anti-Stokes Raman Scattering (CARS)

    E-Print Network [OSTI]

    Greenaway, Alan

    Coherent anti-Stokes Raman Scattering (CARS) For the study of biofilms Alexander Mc Vey1, Nils.f.mcvey@ed.ac.uk Polystyrene beads of diameter 2µm as imaged by the CARS system at COSMIC, The University of Edinburgh #12;Introduction Outline of CARS CARS set-up Results ­ Pushing the limits Results ­ Imaging E. coli Where do we go

  9. Exciton coherence lifetimes from electronic structure

    E-Print Network [OSTI]

    John Parkhill; David Tempel; Alan Aspuru-Guzik

    2011-12-13

    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.

  10. Coherent multilayer crystals and method of making

    DOE Patents [OSTI]

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

    1980-10-30

    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.

  11. Coherent Radiation Effects in the LCLS Undulator

    SciTech Connect (OSTI)

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

    2010-12-14

    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.

  12. Comment on "Coherence and Uncertainty in Nanostructured Organic Photovoltaics"

    E-Print Network [OSTI]

    Mukamel, Shaul

    Comment on "Coherence and Uncertainty in Nanostructured Organic Photovoltaics" Shaul Mukamel of the eigenfunctions of the Schrodinger equation that describes the nanostructured organic photovoltaic blend. (2 universal "coherence effects" in photovoltaics is misguided. There are two types of coherences in many

  13. 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

  14. Software-Based Cache Coherence with Hardware-Assisted Selective

    E-Print Network [OSTI]

    Cintra, Marcelo

    Software-Based Cache Coherence with Hardware-Assisted Selective Self-Invalidations Using Bloom memory consistency models on top of hardware caches gives rise to the well-known cache coherence problem. The standard solution involves implementing coherence protocols in hardware, an approach with some design

  15. Coherent states of non-Hermitian quantum systems

    E-Print Network [OSTI]

    B. Roy; P. Roy

    2006-06-21

    We use the Gazeau-Klauder formalism to construct coherent states of non-Hermitian quantum systems. In particular we use this formalism to construct coherent state of a PT symmetric system. We also discuss construction of coherent states following Klauder's minimal prescription.

  16. Risk Assessment Coherent Risks: An Axiomatic Approach Relation with Cooperative Game Concluding Remarks Risk, Coherency and Cooperative Game

    E-Print Network [OSTI]

    Li, Haijun

    Risk Assessment Coherent Risks: An Axiomatic Approach Relation with Cooperative Game Concluding 2011 1 / 30 #12;Risk Assessment Coherent Risks: An Axiomatic Approach Relation with Cooperative Game Concluding Remarks Outline 1 Risk Assessment Risk = Volatility? Modern Portfolio Theory (MPT) Risk

  17. 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

    2006-02-01

    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.

  18. Coherence resonance near blowout bifurcation in nonlinear dynamical systems

    E-Print Network [OSTI]

    Bambi Hu; Changsong Zhou

    2000-05-29

    Previous studies have shown that noise can induce coherence resonance in some nonlinear dynamical systems close to a bifurcation of a periodic motion, such as in excitable systems. We demonstrate that coherence resonance can be observed in systems close to a {\\sl blowout bifurcation}. It is shown that for dynamical systems with an invariant subspace in which there is a phase-coherent chaotic attractor, the interplay among the oscillation of local transverse stability, noise and nonlinearity can lead to coherence resonance phenomenon. The mechanism of coherence resonance in this type of system is different from that in previously studied systems.

  19. SU-E-T-506: Dosimetric Verification of Photon MLC Delivered Electron Fields for Implementing MERT On An Artiste Linac

    SciTech Connect (OSTI)

    Jin, L; Eldib, A; Li, J; Wang, L; Ma, C; Fan, J

    2014-06-01

    Purpose: To verify the dose accuracy of photon MLC delivered electron fields for implementing energy-intensity modulated electron radiotherapy (MERT) on an Artiste linac. Methods: It was proposed to deliver MERT on an Artiste linac at a short SSD (60 cm) to reduce beam penumbra caused by electron scatters. An in-house developed Monte Carlo (MC)-based dose calculation/optimization planning code was used for treatment planning. Our previous study showed that the measured dose distribution of a breast plan showed good agreement with the calculations in low-medium dose regions while the differences in high dose regions were outstanding. A continuous work found that the discrepancy is mainly caused by improper modeling in MC for the single focused MLC in the Artiste which was simplified as double focused in the previous MC simulations. With this remodeled MLC in the calculations, an energy-intensity modulated electron plan using 6, 9, 12 and 15 MeV was generated for a breast treatment on a breast phantom at a 60 cm SSD and recalculated regarding a solid water phantom. For a test study, four of MLC segments (each with a different energy) generated in the plan were delivered to the phantom and a film measurement was performed at the depth of 2 cm. The measured 2D dose distribution was then compared with calculations. Results: For composite doses of the four segments, measured 2D dose distributions overall agree well with the calculations (3mm/3%) in most area. The separate measurement for a single MLC segment for each of energies also showed the consistence with the calculations. Conclusion: After remodeling MLC in the MC calculations, the measured dose distribution for a subset of MLC segments from a MERT plan showed good agreement. Further detailed verification for the full plan will be the work in the next step.

  20. Interplay between consensus and coherence in a model of interacting opinions

    E-Print Network [OSTI]

    Battiston, Federico; Nicosia, Vincenzo; Baule, Adrian; Latora, Vito

    2015-01-01

    In real societies individuals are constantly subject to external stimuli, such as peer and media pressure, which often have a substantial impact on the formation of their opinions. Normally, in a social system, each agent interacts with other agents on different topics, such as politics, religion, economy, and is subject to the pressure of exogenous forces, including mass media. As a result, its public profile is a non-trivial combination of its opinions on several different aspects. While often trying to mould its own ideas according to the combined effects of social and media pressure, each agent also identifies meaningful relationships among its opinions on different subjects, and naturally aims at building a coherent cultural profile. Here we propose a simple model in which coherent agents, interacting on several layers representing different topics, tend to spread their own ideas to their neighbourhoods, and are at the same time subject to external fields which play the role of mass media pressure. We sh...

  1. 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

    2013-01-01

    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.

  2. Coherent water transport across the South Atlantic

    E-Print Network [OSTI]

    Wang, Y; Beron-Vera, F J

    2015-01-01

    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.

  3. Mode Selective Excitation Using Coherent Control Spectroscopy

    SciTech Connect (OSTI)

    Singh, Ajay K.; Konradi, Jakow; Materny, Arnulf; Sarkar, Sisir K.

    2008-11-14

    Femtosecond time-resolved coherent anti-Stokes Raman scattering (fs-CARS) gives access to ultrafast molecular dynamics. However, femtosecond laser pulses are spectrally broad and therefore coherently excite several molecular modes. While the temporal resolution is high, usually no mode-selective excitation is possible. This paper demonstrates the feasibility of selectively exciting specific molecular vibrations in solution phase with shaped fs laser excitation using a feedback-controlled optimization technique guided by an evolutionary algorithm. This approach is also used to obtain molecule-specific CARS spectra from a mixture of different substances. The optimized phase structures of the fs pulses are characterized to get insight into the control process. Possible applications of the spectrum control are discussed.

  4. Defining Coherent Vortices Objectively from the Vorticity

    E-Print Network [OSTI]

    Haller, George; Farazmand, Mohammad; Huhn, Florian

    2015-01-01

    Rotationally coherent Lagrangian vortices are formed by tubes of deforming fluid elements that complete equal bulk material rotation relative to the mean rotation of the deforming fluid volume. We show that initial positions of such tubes coincide with tubular level surfaces of the Lagrangian-Averaged Vorticity Deviation (LAVD), the trajectory integral of the normed difference of the vorticity from its spatial mean. LAVD-based vortices are objective, i.e., remain unchanged under time-dependent rotations and translations of the coordinate frame. In the limit of vanishing Rossby numbers in geostrophic flows, cyclonic LAVD vortex centers are precisely the observed attractors for light particles. A similar result holds for heavy particles in anticyclonic LAVD vortices. We also establish a relationship between rotationally coherent Lagrangian vortices and their instantaneous Eulerian counterparts. The latter are formed by tubular surfaces of equal material rotation rate, objectively measured by the Instantaneous V...

  5. Coherent bremsstrahlung in a bent crystal

    E-Print Network [OSTI]

    M. V. Bondarenco

    2010-06-04

    Radiation spectrum from high energy $e^\\pm$ in a bent crystal with arbitrary curvature distribution along the longitudinal coordinate is evaluated, based on the stationary phase approximation. For a uniformly bent crystal a closed-form expression for the spectrum is derived. Features such as sharp end of spectrum and volume reflection turnover at beginning of the spectrum are discussed. The coherence length in a bent crystal appears to depend only on the crystal geometry and not on the electron or photon energies, which is essential for interpretation of the results. Estimates of non-dipole radiation and multiple scattering effects are given. The value for the crystal bending angle at which the dipole coherent bremsstrahlung theory holds best appears to be $\\sim 10^{-4}\\mathrm{rad}$.

  6. Multiplex coherent raman spectroscopy detector and method

    DOE Patents [OSTI]

    Chen, Peter; Joyner, Candace C.; Patrick, Sheena T.; Guyer, Dean R.

    2004-06-08

    A multiplex coherent Raman spectrometer (10) and spectroscopy method rapidly detects and identifies individual components of a chemical mixture separated by a separation technique, such as gas chromatography. The spectrometer (10) and method accurately identify a variety of compounds because they produce the entire gas phase vibrational Raman spectrum of the unknown gas. This is accomplished by tilting a Raman cell (20) to produce a high-intensity, backward-stimulated, coherent Raman beam of 683 nm, which drives a degenerate optical parametric oscillator (28) to produce a broadband beam of 1100-1700 nm covering a range of more than 3000 wavenumber. This broadband beam is combined with a narrowband beam of 532 nm having a bandwidth of 0.003 wavenumbers and focused into a heated windowless cell (38) that receives gases separated by a gas chromatograph (40). The Raman radiation scattered from these gases is filtered and sent to a monochromator (50) with multichannel detection.

  7. Saving the Coherent State Path Integral

    E-Print Network [OSTI]

    Yariv Yanay; Erich J. Mueller

    2013-03-19

    By returning to the underlying discrete time formalism, we relate spurious results in coherent state path integral calculations to the high frequency structure of their propagators. We show how to modify the standard expressions for thermodynamic quantities to yield correct results. These expressions are relevant to a broad range of physical problems, from the thermodynamics of Bose lattice gases to the dynamics of spin systems.

  8. COHERENT LASER VISION SYSTEM (CLVS) OPTION PHASE

    SciTech Connect (OSTI)

    Robert Clark

    1999-11-18

    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.

  9. Method and apparatus for coherent burst ranging

    DOE Patents [OSTI]

    Wachter, E.A.; Fisher, W.G.

    1998-04-28

    A high resolution ranging method is described utilizing a novel modulated waveform, hereafter referred to as coherent burst modulation. In the coherent burst method, high frequency modulation of an acoustic or electromagnetic transmitter, such as a laser, is performed at a modulation frequency. This modulation frequency is transmitted quasi-continuously in the form of interrupted bursts of radiation. Energy from the transmitter is directed onto a target, interacts with the target, and the returning energy is collected. The encoded burst pattern contained in the collected return signal is detected coherently by a receiver that is tuned so as to be principally sensitive to the modulation frequency. The receiver signal is processed to determine target range using both time-of-flight of the burst envelope and phase shift of the high frequency modulation. This approach effectively decouples the maximum unambiguous range and range resolution relationship of earlier methods, thereby allowing high precision ranging to be conducted at arbitrarily long distances using at least one burst of encoded energy. The use of a receiver tuned to the high frequency modulation contained within the coherent burst vastly improves both sensitivity in the detection of the target return signal and rejection of background interferences, such as ambient acoustic or electromagnetic noise. Simultaneous transmission at several energies (or wavelengths) is possible by encoding each energy with a separate modulation frequency or pattern; electronic demodulation at the receiver allows the return pattern for each energy to be monitored independently. Radial velocity of a target can also be determined by monitoring change in phase shift of the return signal as a function of time. 12 figs.

  10. Method and apparatus for coherent burst ranging

    DOE Patents [OSTI]

    Wachter, Eric A. (138 Bay Path Dr., Oak Ridge, TN 37830); Fisher, Walter G. (8514 Carl Valentine, Knoxville, TN 37931)

    1998-01-01

    A high resolution ranging method is described utilizing a novel modulated waveform, hereafter referred to as coherent burst modulation. In the coherent burst method, high frequency modulation of an acoustic or electromagnetic transmitter, such as a laser, is performed at a modulation frequency. This modulation frequency is transmitted quasi-continuously in the form of interrupted bursts of radiation. Energy from the transmitter is directed onto a target, interacts with the target, and the returning energy is collected. The encoded burst pattern contained in the collected return signal is detected coherently by a receiver that is tuned so as to be principally sensitive to the modulation frequency. The receiver signal is processed to determine target range using both time-of-flight of the burst envelope and phase shift of the high frequency modulation. This approach effectively decouples the maximum unambiguous range and range resolution relationship of earlier methods, thereby allowing high precision ranging to be conducted at arbitrarily long distances using at least one burst of encoded energy. The use of a receiver tuned to the high frequency modulation contained within the coherent burst vastly improves both sensitivity in the detection of the target return signal and rejection of background interferences, such as ambient acoustic or electromagnetic noise. Simultaneous transmission at several energies (or wavelengths) is possible by encoding each energy with a separate modulation frequency or pattern; electronic demodulation at the receiver allows the return pattern for each energy to be monitored independently. Radial velocity of a target can also be determined by monitoring change in phase shift of the return signal as a function of time.

  11. SU-E-T-06: A Comparison of IMRT Treatment of Esophageal Carcinoma in Elekta-Precise and Varian23EX Linac

    SciTech Connect (OSTI)

    Bai, W; Fan, X; Qiu, R; Qiao, X; Zhang, R [Hebei Medical University Fourth Hospital, Shijiazhuang, Hebei (China)

    2014-06-01

    Purpose: To compare and analyze the characteristics of static intensity-modulated radiotherapy (IMRT) plans designed on Elekta and Varian Linac in different esophageal cancer(EC), exploring advantages and disadvantages of different vendor Linac, thus can be better serve for clinical. Methods: Twenty-four patients with EC were selected, including 6 cases located in the cervical, upper, middle and the lower thorax, respectively. Two IMRT plans were generated with the Oncentra planning system: in Elekta and Varian Linac, prescription dose of 60Gy in 30 fractions to the PTV. We examined the dose-volume histogram parameters of PTV and the organs at risk (OAR) such as lungs, spinal cord and heart, and additional Monitor units(MU), treatment time, Homogeneity index(HI), Conformity index(CI) and Gamma index comparisons were performed. Results: All plans resulted in abundant dose coverage of PTV for EC of different locations. The doses to PTV, HI and OAR in Elekta plans were not statistically different in comparison with Varian plans, with the following exceptions: in cervical, upper and lower thoracic EC the PTV's CI, and in middle thorax EC PTV's D2, D50, V105 and PTV-average were better in Elekta plans than in Varian plans. In the cervical, upper and the middle thorax EC, treatment time were significantly decreased in Varian plans as against Elekta plans, while in the lower thoracic EC treatment time were no striking difference. MUs and gamma index were similar between the two Linac plans. Conclusion: For the the middle thorax EC Varian plans is better than Elekta plans, not only in treatment time but in the PTV dose; while for the lower thorax EC Elekta plans is the first choice for better CI; for the other part of the EC usually Elekta plans can increase the CI, while Varian plans can reduce treatment time, can be selected according to the actual situation of the patient treatment.

  12. Comparison of electric and magnetic quadrupole focusing for the low energy end of an induction-linac-ICF (Inertial-Confinement-Fusion) driver

    SciTech Connect (OSTI)

    Kim, C.H.

    1987-04-01

    This report compares two physics designs of the low energy end of an induction linac-ICF driver: one using electric quadrupole focusing of many parallel beams followed by transverse combining; the other using magnetic quadrupole focusing of fewer beams without beam combining. Because of larger head-to-tail velocity spread and a consequent rapid current amplification in a magnetic focusing channel, the overall accelerator size of the design using magnetic focusing is comparable to that using electric focusing.

  13. SU-E-T-569: Evaluation of VMAT Plans Generated with HD120 and Millennium 120 MLC Between Two Matched Linacs

    SciTech Connect (OSTI)

    Cui, G; Ballas, L; Chang, E; Chung, E; Chiu, R; Cummings, D; Shiu, A

    2014-06-01

    Purpose: To evaluate VMAT treatment plans generated with HD120 MLC and Millennium 120 MLC between two matched linacs and to determine if one can back up the other. Methods: The 6x photon beams are matched for our Varian TrueBeam STx and Trilogy linacs, which are equipped with HD120 MLC and Millennium 120 MLC, respectively. Three prostate and three brain VMAT plans were used for the evaluation. Five plans (three prostate and two brain plans) were originally generated with the TrueBeam STx and re-computed with the Trilogy. One brain plan was evaluated the other way around. For each plan, the PTV coverage of V95 was made the same between two linacs. The dosimetric differences associated with the plans were compared using: 1) Percentage mean dose differences to the PTV, 2) Homogeneity index, HI = (Dmax ? Dmin)/Dmean for the PTV. For prostate plans, the mean dose differences to the rectum were evaluated. While for brain plans, the percentage max dose differences to the lenses (left and right lens) were evaluated. Results: For three prostate plans, the average of the percentage mean dose differences to the PTV was 0.5 ± 0.1% and the HI was 0.1 ± 0.0%. The average of the percentage mean dose difference to the rectum was 3.5 ± 0.5%. For three brain plans, the average of the percentage mean dose differences to the PTV was 0.2 ± 1.1% and the HI was 0.2 ± 0.1%. The average of the percentage max dose differences to the lenses was 22.9 ± 4.0%. Conclusion: For prostate VMAT plans, changing the treatment from the TrueBeam STx to the Trilogy does not necessarily need re-optimization. But for brain plans, in order to minimize dose to the lenses, it is recommended to re-optimize the plan if changing the treatment between these two linacs.

  14. Robust quantum spatial coherence near a classical environment

    E-Print Network [OSTI]

    Zhou, Shuyu; Keil, Mark; Japha, Yonathan; Folman, Ron

    2015-01-01

    In quantum physics spatial coherence allows a massive object to be present in two locations at the same time. Such spatial coherence is easily lost in the presence of a classical environment, making it unobservable in our day-to-day experience. Here we report the persistence of spatial coherence for ultra-cold atoms held only 5$\\,\\mu$m from a room temperature surface, reducing substantially the distance previously achieved between trapped atoms exhibiting spatial coherence and their classical environment. At this distance, the environment would normally destroy spatial coherence over any length greater than a few micrometers, but we nevertheless observe coherence over a length of 30$\\,\\mu$m. We show that no observable dephasing is taking place, even on a time scale on the order of one second. From a technological point of view, this may enable quantum devices based on atomic circuits.

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

    SciTech Connect (OSTI)

    Uenal, Nuri

    2013-10-15

    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.

  16. A note on coherence power of N-dimensional unitary operators

    E-Print Network [OSTI]

    M. García-Díaz; D. Egloff; M. B. Plenio

    2015-10-22

    The coherence power of a quantum channel, that is, its ability to increase the coherence of input states, is a fundamental concept within the framework of the resource theory of coherence. In this note we discuss various possible definitions of coherence power. Then we prove that the coherence power of a unitary operator acting on a qubit, computed with respect to the $l_1$-coherence measure, can be calculated by maximizing its coherence gain over pure incoherent states. We proceed to show that this result fails for dimensions N>2, that is, the maximal coherence gain is found when acting on a state with non-vanishing coherence.

  17. RF CAVITY PERFORMANCE in the ISAC-II SUPERCONDUCTING HEAVY ION LINAC

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMassR&D100 Winners * Impacts on Global TechnologyProceeding Sign In About227REVIEWOct.

  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. Evaluation of partial coherence correction in X-ray ptychography

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

    Burdet, Nicolas; Shi, Xiaowen; Parks, Daniel; Clark, Jesse N.; Huang, Xiaojing; Kevan, Stephen D.; Robinson, Ian K.

    2015-02-23

    Coherent X-ray Diffraction Imaging (CDI) and X-ray ptychography both heavily rely on the high degree of spatial coherence of the X-ray illumination for sufficient experimental data quality for reconstruction convergence. Nevertheless, the majority of the available synchrotron undulator sources have a limited degree of partial coherence, leading to reduced data quality and a lower speckle contrast in the coherent diffraction patterns. It is still an open question whether experimentalists should compromise the coherence properties of an X-ray source in exchange for a higher flux density at a sample, especially when some materials of scientific interest are relatively weak scatterers. Amore »previous study has suggested that in CDI, the best strategy for the study of strong phase objects is to maintain a high degree of coherence of the illuminating X-rays because of the broadening of solution space resulting from the strong phase structures. In this article, we demonstrate the first systematic analysis of the effectiveness of partial coherence correction in ptychography as a function of the coherence properties, degree of complexity of illumination (degree of phase diversity of the probe) and sample phase complexity. We have also performed analysis of how well ptychographic algorithms refine X-ray probe and complex coherence functions when those variables are unknown at the start of reconstructions, for noise-free simulated data, in the case of both real-valued and highly-complex objects.« less

  20. Part 2: Coherent emission from Free Electron Lasers

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

    beam from conventional accelerators is presented. Both spontaneous and coherent emission of electrons is considered. Introduction The importance of the time-resolved studies...

  1. 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

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

    E-Print Network [OSTI]

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

    2010-12-20

    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.

  3. Detection of coherent acoustic oscillations in a quantum electromechanical resonator

    E-Print Network [OSTI]

    Ludwig-Maximilians-Universität, München

    Detection of coherent acoustic oscillations in a quantum electromechanical resonator Florian W electromechanical QEM systems, such as nano- mechanical resonators, the different eigenstates correspond

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

    E-Print Network [OSTI]

    Herz, Paul Richard, 1972-

    2004-01-01

    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 ...

  5. 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)

    2002-01-01

    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.

  6. Coherent diffractive imaging of single layer microspheres

    SciTech Connect (OSTI)

    Dinh, Khuong Ba Le, Hoang Vu; Van Vuong, Cuong; Hannaford, Peter; Van Dao, Lap; Ong, Adabelle X. P.; Henderson, Clare A.; Smith, Trevor A.

    2015-04-28

    We report the extreme ultraviolet (XUV) coherent diffractive imaging of silica/polymer micro-particle samples illuminated by a table-top high harmonic generation source at the wavelength of 30?nm. We achieve images constructed from diffraction patterns acquired with 13??m × 13??m samples comprising a sparse monolayer of spherical silica and polymer micro-particles. Successful reconstructed image of an aperiodic sample using this HHG source will open the path to the realization of a compact soft x-ray microscope to investigate other complex absorbing samples.

  7. Multi-dimensional trio coherent states

    E-Print Network [OSTI]

    Hyo Seok Yi; Ba An Nguyen; Jaewan Kim

    2004-09-16

    We introduce a novel class of higher-order, three-mode states called K-dimensional trio coherent states. We study their mathematical properties and prove that they form a complete set in a truncated Fock space. We also study their physical content by explicitly showing that they exhibit nonclassical features such as oscillatory number distribution, sub-poissonian statistics, Cauchy-Schwarz inequality violation and phase-space quantum interferences. Finally, we propose an experimental scheme to realize the state with K=2 in the quantized vibronic motion of a trapped ion.

  8. Coherence properties of discrete static kinks

    E-Print Network [OSTI]

    H. Landa

    2010-02-01

    A chain of interacting particles subject also to a nonlinear on-site potential admits stable soliton-like configurations : static kinks. The linear normal-modes around such a kink contain a discrete set of localized, gap-separated modes. Quantization of the Hamiltonian in these modes results in an interacting system of phonons. We investigate numerically the coherence properties of such localized modes at low temperatures using a non-Markovian master equation. We show that low decoherence rates can be achieved in these nonlinear configurations for a surprisingly long time. If realized in the ion trap, kink internal modes may be advantageously used for Quantum Information Processing.

  9. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B LReports from the Cloud ModelingPractices for HybridCOHERENT

  10. 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)

    2002-01-01

    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.

  11. Coherent, Mechanical Control of a Single Electronic Spin Sungkun Hong,,

    E-Print Network [OSTI]

    Yacoby, Amir

    Coherent, Mechanical Control of a Single Electronic Spin Sungkun Hong,, Michael S. Grinolds coherent quantum control of a single spin driven by the motion of a mechanical resonator. The motion of a mechanical resonator is magnetically coupled to the electronic spin of a single nitrogen-vacancy center

  12. Knowledge Media Institute Cognitive Coherence Relations and Hypertext

    E-Print Network [OSTI]

    Knowledge Media Institute Cognitive Coherence Relations and Hypertext: From Cinematic Coherence Relations and Hypertext: From Cinematic Patterns to Scholarly Discourse Clara Mancini and Simon-mail:{C.Mancini,S.Buckingham.Shum}@open.ac.uk ABSTRACT In previous work we argued that cinematic language may provide insights into the construction

  13. Coherence and Confirmation Through Causation Gregory Wheeler and Richard Scheines

    E-Print Network [OSTI]

    Spirtes, Peter

    in the murder of her employer, Dr. Black. Each of their statements alone is damaging to White, yet both the example of Black's murder. The case against White collapses not because of a change in the coherence murder mystery, in the absence of a detailed theory of coherence. In this paper we attempt to follow

  14. EFFICIENT, SNOOPLESS, SYSTEM-ON-CHIP COHERENCE Stefanos Kaxiras(1)

    E-Print Network [OSTI]

    Acacio, Manuel

    bits, invalidations, etc.) in exchange for a clean and uniform shared memory model. As it is typical and costs (power). In essence, we remove all coherence decisions from local caches by simply determining L1, shared cache, and bus energy consumption. I. INTRODUCTION While the benefits of a coherent

  15. Generation of Coherent Institute for Perception Research (IPO)

    E-Print Network [OSTI]

    Theune, Mariët

    Generation of Coherent Monologues Jan Odijk Institute for Perception Research (IPO) P.O.Box 513 for generating coherent texts is de- scribed. In this method only local conditions associated with sentences any form of planning and it concentrates on maximizing the amount of variation of the texts generated

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

    E-Print Network [OSTI]

    Loss, Daniel

    ARTICLES Coherent spinor dynamics in a spin-1 Bose condensate MING-SHIEN CHANG, QISHU QIN, WENXIAN, 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

  17. Coherent transition radiation from a helically microbunched electron beam

    SciTech Connect (OSTI)

    Hemsing, E.; Rosenzweig, J. B. [Department of Physics and Astronomy, Particle Beam Physics Laboratory, University of California Los Angeles, Los Angeles, California 90095 (United States)

    2009-05-01

    The coherent transition radiation emitted from an electron beam with higher-order spatial microbunching is analyzed. The characteristic angular and phase dependence can be used to identify the dominant bunching structure of such beams, which can be generated during the harmonic interaction in optical klystron modulators and free-electron lasers, and used as tunable sources of coherent light with orbital angular momentum.

  18. 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

  19. Analysis of Coherence Properties of 3rd Generation Synchrotron Sources

    E-Print Network [OSTI]

    physics 0907.4009 ########### Analysis of Coherence Properties of 3­rd Generation Synchrotron is used for the analysis of the transverse coherence properties of 3­rd generation synchrotron sources [physics.optics] 23 Jul 2009 #12; 1 Introduction With the construction of 3­rd generation, hard x

  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. Discovering Coherent Biclusters from Gene Expression Data Using

    E-Print Network [OSTI]

    Nardini, Christine

    ,and it is often computationally costly to find biclusters with high levels of coherence. In this work, we propose], [8], [13], [15], [16], [21], [26], [29], [31], [33], [34] is one of the most promising innovations in area B are less interesting because they have a lower level of coherence than those in areas A or C

  2. Coherence area profiling in multi-spatial-mode squeezed states

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

    Lawrie, Benjamin J.; Pooser, Raphael C.; Otterstrom, Nils T.

    2015-09-12

    The presence of multiple bipartite entangled modes in squeezed states generated by four-wave mixing enables ultra-trace sensing, imaging, and metrology applications that are impossible to achieve with single-spatial-mode squeezed states. For Gaussian seed beams, the spatial distribution of these bipartite entangled modes, or coherence areas, across each beam is largely dependent on the spatial modes present in the pump beam, but it has proven difficult to map the distribution of these coherence areas in frequency and space. We demonstrate an accessible method to map the distribution of the coherence areas within these twin beams. We also show that the pumpmore »shape can impart different noise properties to each coherence area, and that it is possible to select and detect coherence areas with optimal squeezing with this approach.« less

  3. Quantum coherence, time-translation symmetry and thermodynamics

    E-Print Network [OSTI]

    Matteo Lostaglio; Kamil Korzekwa; David Jennings; Terry Rudolph

    2015-04-13

    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.

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

    E-Print Network [OSTI]

    Ahsen, Osman Oguz

    2013-01-01

    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 ...

  5. 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...

  6. Effects of phase and coupling between the vibrational modes on selective excitation in coherent anti-Stokes Raman scattering microscopy

    SciTech Connect (OSTI)

    Patel, Vishesha; Malinovsky, Vladimir S.; Malinovskaya, Svetlana

    2010-06-15

    Coherent anti-Stokes Raman scattering (CARS) microscopy has been a major tool of investigation of biological structures as it contains the vibrational signature of molecules. A quantum control method based on chirped pulse adiabatic passage was recently proposed for selective excitation of a predetermined vibrational mode in CARS microscopy [Malinovskaya and Malinovsky, Opt. Lett. 32, 707 (2007)]. The method utilizes the chirp sign variation at the peak pulse amplitude and gives a robust adiabatic excitation of the desired vibrational mode. Using this method, we investigate the impact of coupling between vibrational modes in molecules on controllability of excitation of the CARS signal. We analyze two models of two coupled two-level systems (TLSs) having slightly different transitional frequencies. The first model, featuring degenerate ground states of the TLSs, gives robust adiabatic excitation and maximum coherence in the resonant TLS for positive value of the chirp. In the second model, implying nondegenerate ground states in the TLSs, a population distribution is observed in both TLSs, resulting in a lack of selectivity of excitation and low coherence. It is shown that the relative phase and coupling between the TLSs play an important role in optimizing coherence in the desired vibrational mode and suppressing unwanted transitions in CARS microscopy.

  7. Communication via entangled coherent quantum network

    E-Print Network [OSTI]

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

    2010-11-17

    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.

  8. Lagrangian coherent structures and plasma transport processes

    E-Print Network [OSTI]

    Falessi, M V; Schep, T J

    2015-01-01

    A dynamical system framework is used to describe transport processes in plasmas embedded in a magnetic field. For periodic systems with one degree of freedom the Poincar\\'e map provides a splitting of the phase space into regions where particles have different kinds of motion: periodic, quasi-periodic or chaotic. The boundaries of these regions are transport barriers; i.e., a trajectory cannot cross such boundaries during the whole evolution of the system. Lagrangian Coherent Structure (LCS) generalize this method to systems with the most general time dependence, splitting the phase space into regions with different qualitative behaviours. This leads to the definition of finite-time transport barriers, i.e. trajectories cannot cross the barrier for a finite amount of time. This methodology can be used to identify fast recirculating regions in the dynamical system and to characterize the transport between them.

  9. Birefringence insensitive optical coherence domain reflectometry system

    DOE Patents [OSTI]

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

    2002-01-01

    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.

  10. Improvement of dose distribution in breast radiotherapy using a reversible transverse magnetic field Linac-MR unit

    SciTech Connect (OSTI)

    Esmaeeli, A. D.; Mahdavi, S. R.; Pouladian, M.; Bagheri, S.; Monfared, A. S.

    2014-01-15

    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.

  11. DEPARTMENT OF I Office

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

    SLAC Site Office Enter APS report date here Linac Coherent Light Source-II, Menlo Park, California (EA No. DOEEA-1904) 115,000 The proposed Linac Coherent Light Source...

  12. Unambiguous coherent state identification: Searching a quantum database

    E-Print Network [OSTI]

    Michal Sedlak; Mario Ziman; Ondrej Pribyla; Vladimir Buzek; Mark Hillery

    2007-07-23

    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.

  13. Two photon amplitude of partially coherent partially entangled electromagnetic fields

    E-Print Network [OSTI]

    Miguel Angel Olvera; Sonja Franke-Arnold

    2015-07-30

    The development of efficient protocols for pure and mixed states preparation is challenging task. Most of the theory of quantum information applications has been developed for fully coherent or completely incoherent light. However, in many situations of interest partially coherent light has been proved to be a more robust model of radiation. In this paper the underpinning theory of two photon amplitude functions for down-converted fields with partially coherent pump beams is investigated. By using the generalised Siegert relations and the coherent mode representation of the cross spectral density matrix the two photon amplitude is fully characterised for partially coherent beams. A number of correlation properties from modern coherence theory are demonstrated to be preserved under parametric down-conversion. Based on the generalised Siegert relations and the Cauchy-Schwarz inequality a measure of entanglement for the two photon amplitude is proposed. Upper bounds for this measure are found in terms of the \\emph{golden ratio} for maximally entangled states. Two inequalities are derived for the two photon amplitude for which there exist a transition zone from super-Poisson statistics to sub-Poisson statistics for down-converted partially coherent fields.

  14. Static IMRT and VMAT planning on 6 MV Flattened and Flattening-Filter-Free Beams of a TrueBeam VirtuaLinac System

    E-Print Network [OSTI]

    Yan, Yue; Saenz, Daniel; Paliwal, Bhudatt R

    2015-01-01

    In this manuscript, we investigated the accuracy of the entire chain of phase space files generated by the TrueBeam VirtuaLinac system in clinical treatment plans. Good agreement was obtained between the MC simulation and the clinical golden data for both flattened and FFF beams. The relative magnitude of agreement between MC and golden beam data presented in this research may assist a physicist in terms of the percent dose deviation that one may expect when using MC data for verification purposes.

  15. Coherent structures in compressible free-shear-layer flows

    SciTech Connect (OSTI)

    Aeschliman, D.P.; Baty, R.S.; Kennedy, C.A.; Chen, J.H.

    1997-08-01

    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.

  16. Some features of photolithography image formation in partially coherent light

    SciTech Connect (OSTI)

    Kitsak, M A; Kitsak, A I

    2010-12-09

    The coherent-noise level in projection images of an opaque-screen sharp edge, formed in the model scheme of photolithography system at different degrees of spatial coherence of screen-illuminating light is studied experimentally. The spatial coherence of laser radiation was reduced by applying a specially developed device, used as a separate functional unit in the system model. The smoothing of the spatial fluctuations of radiation intensity caused by the random spatial inhomogeneity of the initial beam intensity in the obtained images is shown to be highly efficient. (imaging and image processing. holography)

  17. FY 2016 Budget Request to Congress for DOE's Office of Science

    E-Print Network [OSTI]

    ), which provides the electron beam for the new Linac Coherent Light Source (LCLS) ­ the world's first hard

  18. High-order temporal coherences of chaotic and laser light

    E-Print Network [OSTI]

    Berggren, Karl K.

    We demonstrate a new approach to measuring high-order temporal coherences that uses a four-element superconducting nanowire single-photon detector. The four independent, interleaved single-photon-sensitive elements parse ...

  19. Observation of Coherence in the Photosystem II Reaction Center

    E-Print Network [OSTI]

    Franklin D. Fuller; Jie Pan; S. Seckin Senlik; Daniel E. Wilcox; Jennifer P. Ogilvie

    2013-10-03

    Photosynthesis powers life on our planet. The basic photosynthetic architecture comprises antenna complexes to harvest solar energy and reaction centers to convert the energy into a stable charge separated state. In oxygenic photosynthesis, the initial charge separation event occurs in the photosystem II reaction center; the only known natural enzyme that uses solar energy to split water. Energy transfer and charge separation in photosynthesis are rapid and have high quantum efficiencies. Recently, nonlinear spectroscopic experiments have suggested that electronic coherence may play a role in energy transfer efficiency in antenna complexes. Here we report the observation of coherence in the photosystem II reaction center by two dimensional electronic spectroscopy. The frequencies of the observed coherences match exciton difference frequencies and/or known vibrational modes of the photosystem II reaction center. These observations raise questions about the possible role of electronic and/or vibrational coherence in the fundamental charge separation process in oxygenic photosynthesis.

  20. Ultrahigh speed optical coherence tomography for ophthalmic imaging applications

    E-Print Network [OSTI]

    Liu, Jonathan Jaoshin

    2014-01-01

    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 ...

  1. Temporal coherence of individual turbulent patterns in atmospheric seeing

    E-Print Network [OSTI]

    Dimotakis, Paul E.

    by turbulent mixing of volumes of air with different indices of refraction. Adaptive optics sys- tems designed, under the conditions described above. In this paper we de- scribe a measurement of this coherence time

  2. COHERENT DISCRETE EMBEDDINGS FOR LAGRANGIAN AND HAMILTONIAN SYSTEMS

    E-Print Network [OSTI]

    COHERENT DISCRETE EMBEDDINGS FOR LAGRANGIAN AND HAMILTONIAN SYSTEMS by J. Cresson, I. Greff & C . . ........................................ 6 Part II. Discrete variational embedding of Lagrangian systems . . ...................... 7 4. -- Lagrangian systems, Hamiltonian systems, variational integrators, discrete embeddings, numerical schemes, FEM

  3. Development of Molecular Contrast in Coherence Domain Optical Imaging 

    E-Print Network [OSTI]

    Wan, Qiujie

    2012-02-14

    : Chair of Committee, Brian E. Applegate Committee Members, Alvin T. Yeh Javier Jo Jim Ji Head of Department, Gerard L. Cote December 2011 Major Subject: Biomedical Engineering iii ABSTRACT Development of Molecular Contrast in Coherence...

  4. Coherence characterization with a superconducting flux qubit through NMR approaches

    E-Print Network [OSTI]

    Yan, Fei, Ph. D. Massachusetts Institute of Technology

    2013-01-01

    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 ...

  5. 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

    2007-01-01

    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...

  6. Quantum-optical coherence tomography with collinear entangled photons

    E-Print Network [OSTI]

    Novotny, Lukas

    Quantum-optical coherence tomography with collinear entangled photons Dorilian Lopez-Mago1 Photonics and Mathematical Optics Group, Tecnológico de Monterrey, Monterrey, Nuevo León 64849, Mexico 3 ETH Zürich, Photonics Laboratory, 8093 Zürich, Switzerland *Corresponding author: novotny

  7. Interlayer Coherence and Superconducting Condensate in the c...

    Office of Scientific and Technical Information (OSTI)

    Interlayer Coherence and Superconducting Condensate in the c-Axis Response of Optimally Doped Ba(Fe1-xCox)2As2 High-Tc Superconductor Using Infrared Spectroscopy Citation Details...

  8. Scalable directoryless shared memory coherence using execution migration

    E-Print Network [OSTI]

    Lis, Mieszko

    2010-11-22

    We introduce the concept of deadlock-free migration-based coherent shared memory to the NUCA family of architectures. Migration-based architectures move threads among cores to guarantee sequential semantics in large ...

  9. Suppressing coherent noise in radar applications with long dwell times

    E-Print Network [OSTI]

    Allen, Christopher Thomas; Mozaffar, S. N.; Akins, T. L.

    2005-07-01

    digitally in the transmit waveform and removed digitally following digitization in the receiver. Experimental demonstration of this concept resulted in an additional noise floor reduction of 15 to 20 dB (compared to the conventional coherent averaging alone...

  10. Studying coherence in ultra-cold atomic gases

    E-Print Network [OSTI]

    Miller, Daniel E. (Daniel Edward)

    2007-01-01

    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 ...

  11. Lagrangian Coherent Structures near a Subtropical Jet Stream

    E-Print Network [OSTI]

    Tang, Wenbo

    Direct Lyapunov exponents and stability results are used to extract and distinguish Lagrangian coherent structures (LCS) from a three-dimensional atmospheric dataset generated from the Weather Research and Forecasting (WRF) ...

  12. Generation of Coherent X-Ray Radiation through Modulation Compression...

    Office of Scientific and Technical Information (OSTI)

    In this paper, 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...

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

    E-Print Network [OSTI]

    2012-08-13

    Aug 13, 2012 ... stage a coherent risk measure of future costs is to be minimized. ... very powerful approach in problems involving long$term planning of ...... for a Japanese insurance company using multistage stochastic programming. Inter#.

  14. A Low Overhead Fault Tolerant Coherence Protocol for CMP Architectures

    E-Print Network [OSTI]

    Acacio, Manuel

    A Low Overhead Fault Tolerant Coherence Protocol for CMP Architectures Ricardo Fern Murcia SPAIN {r.fernandez,jmgarcia,meacacio}@ditec.um.es Jos´e Duato Dpto. Inform´atica de Sistemas y

  15. Exploring large coherent spin systems with solid state NMR

    E-Print Network [OSTI]

    Cho, HyungJoon, Ph. D. Massachusetts Institute of Technology

    2005-01-01

    Solid state Nuclear Magnetic Resonance (NMR) allows us to explore a large coherent spin system and provides an ideal test-bed for studying strongly interacting multiple-spin system in a large Hilbert space. In this thesis, ...

  16. Tunneling under Coherent Control by Sequences of Unitary Pulses

    E-Print Network [OSTI]

    Rajdeep Saha; Victor S. Batista

    2010-09-07

    A general coherent control scenario to suppress, or accelerate, tunneling of quantum states decaying into a continuum, is investigated. The method is based on deterministic, or stochastic, sequences of unitary pulses that affect the underlying interference phenomena responsible for quantum dynamics, without inducing decoherence, or collapsing the coherent evolution of the system. The influence of control sequences on the ensuing quantum dynamics is analyzed by using perturbation theory to first order in the control pulse fields and compared to dynamical decoupling (DD) protocols and sequences of pulses that collapse the coherent evolution and induce quantum Zeno (QZE) or quantum anti-Zeno effects (AZE). The analysis reveals a subtle interplay between coherent and incoherent phenomena and demonstrating that dynamics analogous to evolution due to QZE or AZE can be generated from stochastic sequences of unitary pulses when averaged over all possible realizations.

  17. 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 ...

  18. A Study on the Coherent Atomic Effects and Their Applications 

    E-Print Network [OSTI]

    Sun, Qingqing

    2010-07-14

    Coherent atomic states prepared by laser field can have quantum interference between the different transition amplitudes. Therefore, the medium susceptibility and optical response can be engineered, leading to many interesting ...

  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. Coherent multi-photon interference and compensation of polarization dispersion

    E-Print Network [OSTI]

    Fini, John Michael

    2001-01-01

    This thesis will explore strategies for coherent manipulation of multi-photon packets. Correlated multi-photon states can arise in nonlinear optical devices. A nonlinear quantum interferometer which includes these states ...

  1. Coherence and measurement in quantum thermodynamics

    E-Print Network [OSTI]

    Philipp Kammerlander; Janet Anders

    2015-09-18

    Thermodynamics is a highly successful macroscopic theory widely used across the natural sciences and for the construction of everyday devices, from car engines and fridges to power plants and solar cells. With thermodynamics predating quantum theory, research now aims to uncover the thermodynamic laws that govern finite size systems which may in addition host quantum effects. Here we identify information processing tasks, the so-called "projections", that can only be formulated within the framework of quantum mechanics. We show that the physical realisation of such projections can come with a non-trivial thermodynamic work only for quantum states with coherences. This contrasts with information erasure, first investigated by Landauer, for which a thermodynamic work cost applies for classical and quantum erasure alike. Implications are far-reaching, adding a thermodynamic dimension to measurements performed in quantum thermodynamics experiments, and providing key input for the construction of a future quantum thermodynamic framework. Repercussions are discussed for quantum work fluctuation relations and thermodynamic single-shot approaches.

  2. Generation of coherent structures after cosmic inflation

    SciTech Connect (OSTI)

    Gleiser, Marcelo; Stamatopoulos, Nikitas [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States); Graham, Noah [Department of Physics, Middlebury College, Middlebury, Vermont 05753 (United States)

    2011-05-01

    We investigate the nonlinear dynamics of hybrid inflation models, which are characterized by two real scalar fields interacting quadratically. We start by solving numerically the coupled Klein-Gordon equations in static Minkowski spacetime, searching for possible coherent structures. We find long-lived, localized configurations, which we identify as a new kind of oscillon. We demonstrate that these two-field oscillons allow for ''excited'' states with much longer lifetimes than those found in previous studies of single-field oscillons. We then solve the coupled field equations in an expanding Friedmann-Robertson-Walker spacetime, finding that as the field responsible for inflating the Universe rolls down to oscillate about its minimum, it triggers the formation of long-lived two-field oscillons, which can contribute up to 20% of the total energy density of the Universe. We show that these oscillons emerge for a wide range of parameters consistent with WMAP 7-year data. These objects contain total energy of about 25x10{sup 20} GeV, localized in a region of approximate radius 6x10{sup -26} cm. We argue that these structures could have played a key role during the reheating of the Universe.

  3. 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

    2009-04-13

    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.

  4. Transfer information remotely via noise entangled coherent channels

    E-Print Network [OSTI]

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

    2010-02-11

    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.

  5. 500 MW X-Band RF System of a 0.25 GeV Electron LINAC for Advanced Compton Scattering Source Application

    SciTech Connect (OSTI)

    Chu, Tak Sum; /LLNL, Livermore; Anderson, Scott; /LLNL, Livermore; Barty, Christopher; /LLNL, Livermore; Gibson, David; /LLNL, Livermore; Hartemann, Fred; /LLNL, Livermore; Marsh, Roark; /LLNL, Livermore; Siders, Craig; /LLNL, Livermore; Adolphsen, Chris; /SLAC; Jongewaard, Erik; /SLAC; Raubenheimer, Tor; /SLAC; Tantawi, Sami; /SLAC; Vlieks, Arnold; /SLAC; Wang, Juwen; /SLAC

    2012-07-03

    A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL in collaboration with the SLAC National Accelerator Laboratory. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW, 1.5 msec pulses, will be the main high power RF sources for the system. These klystrons will be powered by state of the art solid-state high voltage modulators. A RF pulse compressor, similar to the SLED II pulse compressor, will compress the klystron output pulse with a power gain factor of five. For compactness consideration, we are looking at a folded waveguide setup. This will give us 500 MW at output of the compressor. The compressed pulse will then be distributed to the RF gun and to six traveling wave accelerator sections. Phase and amplitude control are located at the RF gun input and additional control points along the LINAC to allow for parameter control during operation. This high power RF system is being designed and constructed. In this paper, we will present the design, layout, and status of this RF system.

  6. 500 MW X-BAND RF SYSTEM OF A 0.25 GEV ELECTRON LINAC FOR ADVANCED COMPTON SCATTERING SOURCE APPLICATION

    SciTech Connect (OSTI)

    Chu, T S; Anderson, S G; Gibson, D J; Hartemann, F V; Marsh, R A; Siders, C; Barty, C P; Adolphsen, C; Jongewaard, E; Tantawi, S; Vlieks, A; Wang, J W; Raubenheimer, T

    2010-05-12

    A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL in collaboration with SLAC National Accelerator Laboratory. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW, 1.5 msec pulses, will be the main high power RF sources for the system. These klystrons will be powered by state of the art solid-state high voltage modulators. A RF pulse compressor, similar to the SLED II pulse compressor, will compress the klystron output pulse with a power gain factor of five. For compactness consideration, we are looking at a folded waveguide setup. This will give us 500 MW at output of the compressor. The compressed pulse will then be distributed to the RF gun and to six traveling wave accelerator sections. Phase and amplitude control are located at the RF gun input and additional control points along the LINAC to allow for parameter control during operation. This high power RF system is being designed and constructed. In this paper, we will present the design, layout, and status of this RF system.

  7. Observing a coherent superposition of an atom and a molecule

    SciTech Connect (OSTI)

    Dowling, Mark R. [School of Physical Sciences, University of Queensland, St. Lucia, Queensland 4072 (Australia); Bartlett, Stephen D. [School of Physics, University of Sydney, Sydney, New South Wales 2006 (Australia); Rudolph, Terry [Optics Section, Blackett Laboratory, Imperial College London, London SW7 2BW (United Kingdom); Institute for Mathematical Sciences, Imperial College London, London SW7 2BW (United Kingdom); Spekkens, Robert W. [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA (United Kingdom)

    2006-11-15

    We demonstrate that it is possible, in principle, to perform a Ramsey-type interference experiment to exhibit a coherent superposition of a single atom and a diatomic molecule. This gedanken experiment, based on the techniques of Aharonov and Susskind [Phys. Rev. 155, 1428 (1967)], explicitly violates the commonly accepted superselection rule that forbids coherent superpositions of eigenstates of differing atom number. A Bose-Einstein condensate plays the role of a reference frame that allows for coherent operations analogous to Ramsey pulses. We also investigate an analogous gedanken experiment to exhibit a coherent superposition of a single boson and a fermion, violating the commonly accepted superselection rule forbidding coherent superpositions of states of differing particle statistics. In this case, the reference frame is realized by a multimode state of many fermions. This latter case reproduces all of the relevant features of Ramsey interferometry, including Ramsey fringes over many repetitions of the experiment. However, the apparent inability of this proposed experiment to produce well-defined relative phases between two distinct systems each described by a coherent superposition of a boson and a fermion demonstrates that there are additional, outstanding requirements to fully 'lift' the univalence superselection rule.

  8. Coherence and Decoherence in Biological Systems: Principles of Noise Assisted Transport and the Origin of Long-lived Coherences

    E-Print Network [OSTI]

    A. W. Chin; S. F. Huelga; M. B. Plenio

    2012-03-15

    The quantum dynamics of transport networks in the presence of noisy environments have recently received renewed attention with the discovery of long-lived coherences in different photosynthetic complexes. This experimental evidence has raised two fundamental questions: Firstly, what are the mechanisms supporting long-lived coherences and secondly, how can we assess the possible functional role that the interplay of noise and quantum coherence might play in the seemingly optimal operation of biological systems under natural conditions? Here we review recent results, illuminate them at the hand of two paradigmatic systems, the Fenna-Matthew-Olson (FMO) complex and the light harvesting complex LHII, and present new progress on both questions. In particular we introduce the concept of the phonon antennae and discuss the possible microscopic origin or long-lived electronic coherences.

  9. 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.

    2005-01-01

    Backscattered signal of coherent anti-Stokes Raman spectroscopy can be an extremely useful tool for remote identification of airborne particles, provided the signal is sufficiently large. We formulate a semiclassical theory of nonlinear scattering...

  10. Center for Beam Physics

    E-Print Network [OSTI]

    Chattopadhyay, S.

    2010-01-01

    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/

  11. 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

  12. 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

  13. 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...

  14. Klystron-linac combination

    DOE Patents [OSTI]

    Stein, W.E.

    1980-04-24

    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.

  15. REVIEW OF INDUCTION LINACS

    E-Print Network [OSTI]

    Faltens, A.

    2010-01-01

    generator small-signal impedance can be kept small at low frequencies by regulating the output voltage; at high

  16. Alternating phase focused linacs

    DOE Patents [OSTI]

    Swenson, Donald A. (Los Alamos, NM)

    1980-01-01

    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.

  17. LANSCE | About | LINAC

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you notHeat Pumps HeatTechnologies| BlandineHistory The History ofLinear

  18. Pole placement design for quantum systems via coherent observers

    E-Print Network [OSTI]

    Zibo Miao; Matthew R. James; Valery A. Ugrinovskii

    2015-09-17

    We previously extended Luenberger's approach for observer design to the quantum case, and developed a class of coherent observers which tracks linear quantum stochastic systems in the sense of mean values. In light of the fact that the Luenberger observer is commonly and successfully applied in classical control, it is interesting to investigate the role of coherent observers in quantum feedback. As the first step in exploring observer-based coherent control, in this paper we study pole-placement techniques for quantum systems using coherent observers, and in such a fashion, poles of a closed-loop quantum system can be relocated at any desired locations. In comparison to classical feedback control design incorporating the Luenberger observer, here direct coupling between a quantum plant and the observer-based controller are allowed to enable a greater degree of freedom for the design of controller parameters. A separation principle is presented, and we show how to design the observer and feedback independently to be consistent with the laws of quantum mechanics. The proposed scheme is applicable to coherent feedback control of quantum systems, especially when the transient dynamic response is of interest, and this issue is illustrated in an example.

  19. 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

    2015-01-01

    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...

  20. Coherent Feedback Improved Qubit Initialization in the Dispersive Regime

    E-Print Network [OSTI]

    Luke C. G. Govia; Frank K. Wilhelm

    2015-06-17

    Readout of the state of a superconducting qubit by homodyne detection of the output signal from a dispersively coupled microwave resonator is a common technique in circuit quantum electrodynamics, and is often claimed to be quantum non-demolition (QND) up to the same order of approximation as in the dispersive approximation. However, in this work we show that only in the limit of infinite measurement time is this protocol QND, as the formation of a dressed coherent state in the qubit-cavity system applies an effective rotation to the qubit state. We show how this rotation can be corrected by a coherent operation, leading to improved qubit initialization by measurement and coherent feedback.

  1. Entanglement Generated by the Dispersive Interaction: The Dressed Coherent State

    E-Print Network [OSTI]

    Luke C. G. Govia; Frank K. Wilhelm

    2015-06-16

    In the dispersive regime of qubit-cavity coupling, classical cavity drive populates the cavity, but leaves the qubit state unaffected. However, the dispersive Hamiltonian is derived after both a frame transformation and an approximation. Therefore, to connect to external experimental devices, the inverse frame transformation from the dispersive frame back to the lab frame is necessary. In this work, we show that in the lab frame the system is best described by an entangled state known as the dressed coherent state, and thus even in the dispersive regime, entanglement is generated between the qubit and the cavity. Also, we show that further qubit evolution depends on both the amplitude and phase of the dressed coherent state, and use the dressed coherent state to calculate the measurement contrast of a recently developed dispersive readout protocol.

  2. Observing bulk diamond spin coherence in high-purity nanodiamonds

    E-Print Network [OSTI]

    Helena S. Knowles; Dhiren M. Kara; Mete Atature

    2013-10-03

    Nitrogen-vacancy centres (NVs) in diamond are attractive for research straddling quantum information science and nanoscale magnetometry and thermometry. While ultrapure bulk diamond NVs sustain the longest spin coherence times among optically accessible spins, nanodiamond NVs display persistently poor spin coherence. Here we introduce high-purity nanodiamonds accommodating record-long NV coherence times, >60 us, observed via universal dynamical decoupling. We show that the main contribution to decoherence comes from nearby nitrogen impurities rather than surface states. We protect the NV spin free precession, essential to DC magnetometry, by driving solely these impurities into the motional narrowing regime. This extends the NV free induction decay time from 440 ns, longer than that in type Ib bulk diamond, to 1.27 us, which is comparable to that in type IIa (impurity-free) diamond. These properties allow the simultaneous exploitation of both high sensitivity and nanometre resolution in diamond-based emergent quantum technologies.

  3. Method and apparatus for coherent imaging of infrared energy

    DOE Patents [OSTI]

    Hutchinson, Donald P. (Knoxville, TN)

    1998-01-01

    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.

  4. Method and apparatus for coherent imaging of infrared energy

    DOE Patents [OSTI]

    Hutchinson, D.P.

    1998-05-12

    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.

  5. Phase-sensitive fluorescent imaging with coherent reconstruction

    E-Print Network [OSTI]

    Field, Jeffrey J; Bartels, Randy A

    2015-01-01

    Optical imaging plays a critical role in advancing our understanding of three dimensional dynamics of biological systems. Coherent imaging (CI) methods exploit spatial phase information, encoded through propagation of coherent signal light emerging from a specimen, to extract a three-dimensional representation of the object from a single high-speed measurement. Until now, CI methods could not be applied to incoherent light, severely limiting their ability to image the most powerful biological probes available - fluorescent molecules - with sufficient speed and volume to observe important processes, such as neural processing in live specimens. We introduce a new imaging technique that transfers the spatial propagation phase of coherent illumination light to incoherent fluorescent light emission. The transfer of propagation phase allows CI techniques to be applied to fluorescent light imaging, and leads to large increases in imaging speed and depth of field. With this advance, biological imaging of fluorescent ...

  6. Emergence of coherent motion in aggregates of motile coupled maps

    E-Print Network [OSTI]

    Anselmo Garcia Cantu Ros; Chris Antonopoulos; Vasileios Basios

    2011-05-10

    In this paper we study the emergence of coherence in collective motion described by a system of interacting motiles endowed with an inner, adaptative, steering mechanism. By means of a nonlinear parametric coupling, the system elements are able to swing along the route to chaos. Thereby, each motile can display different types of behavior, i.e. from ordered to fully erratic motion, accordingly with its surrounding conditions. The appearance of patterns of collective motion is shown to be related to the emergence of interparticle synchronization and the degree of coherence of motion is quantified by means of a graph representation. The effects related to the density of particles and to interparticle distances are explored. It is shown that the higher degrees of coherence and group cohesion are attained when the system elements display a combination of ordered and chaotic behaviors, which emerges from a collective self-organization process.

  7. A Scalable Architecture for Coherence-Preserving Qubits

    E-Print Network [OSTI]

    Yaakov S. Weinstein; C. Stephen Hellberg

    2006-06-19

    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.

  8. The COHERENT Experiment at the Spallation Neutron Source

    E-Print Network [OSTI]

    COHERENT Collaboration; D. Akimov; P. An; C. Awe; P. S. Barbeau; P. Barton; B. Becker; V. Below; A. Bolozdynya; A. Burenkov; B. Cabrera-Palmer; J. I. Collar; R. J. Cooper; R. L. Cooper; C. Cuesta; D. Dean; J. Detwiler; Y. Efremenko; S. R. Elliott; N. Fields; W. Fox; A. Galindo-Uribarri; M. Green; M. Heath; S. Hedges; N. Herman; D. Hornback; E. B. Iverson; L. Kaufman; S. R. Klein; A. Khromov; A. Konovalev; A. Kumpan; C. Leadbetter; L. Li; W. Lu; A. Melikyan; D. Markoff; K. Miller; M. Middlebrook; P. Mueller; P. Naumov; J. Newby; D. Parno; S. Penttila; G. Perumpilly; D. Radford; H. Ray; J. Raybern; D. Reyna; G. C. Rich; D. Rimal; D. Rudik; K. Scholberg; B. Scholz; W. M. Snow; A. Sosnovchev; A. Shakirov; S. Suchyta; B. Suh; R. Tayloe; R. T. Thornton; A. Tolstukhin; K. Vetter; C. H. Yu

    2015-09-29

    The COHERENT collaboration's primary objective is to measure coherent elastic neutrino-nucleus scattering (CEvNS) using the unique, high-quality source of tens-of-MeV neutrinos provided by the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). In spite of its large cross section, the CEvNS process has never been observed, due to tiny energies of the resulting nuclear recoils which are out of reach for standard neutrino detectors. The measurement of CEvNS has now become feasible, thanks to the development of ultra-sensitive technology for rare decay and weakly-interacting massive particle (dark matter) searches. The CEvNS cross section is cleanly predicted in the standard model; hence its measurement provides a standard model test. It is relevant for supernova physics and supernova-neutrino detection, and enables validation of dark-matter detector background and detector-response models. In the long term, precision measurement of CEvNS will address questions of nuclear structure. COHERENT will deploy multiple detector technologies in a phased approach: a 14-kg CsI[Na] scintillating crystal, 15 kg of p-type point-contact germanium detectors, and 100 kg of liquid xenon in a two-phase time projection chamber. Following an extensive background measurement campaign, a location in the SNS basement has proven to be neutron-quiet and suitable for deployment of the COHERENT detector suite. The simultaneous deployment of the three COHERENT detector subsystems will test the $N^2$ dependence of the cross section and ensure an unambiguous discovery of CEvNS. This document describes concisely the COHERENT physics motivations, sensitivity and plans for measurements at the SNS to be accomplished on a four-year timescale.

  9. SU-E-T-403: Measurement of the Neutron Ambient Dose Equivalent From the TrueBeam Linac Head and Varian 2100 Clinac

    SciTech Connect (OSTI)

    Harvey, M; Pollard, J; Wen, Z; Gao, S

    2014-06-01

    Purpose: High-energy x-ray therapy produces an undesirable source of stray neutron dose to healthy tissues, and thus, poses a risk for second cancer induction years after the primary treatment. Hence, the purpose of this study was to measure the neutron ambient dose equivalent, H*(10), produced from the TrueBeam and Varian 2100 linac heads, respectively. Of particular note is that there is no measured data available in the literature on H*(10) production from the TrueBeam treatment head. Methods: Both linacs were operated in flattening filter mode using a 15 MV x-ray beam on TrueBeam and an 18 MV x-ray beam for the Varian 2100 Clinac with the jaws and multileaf collimators in the fully closed position. A dose delivery rate of 600 MU/min was delivered on the TrueBeam and the Varian 2100 Clinac, respectively and the H*(10) rate was measured in triplicate using the WENDI-2 detector located at multiple positions including isocenter and longitudinal (gun-target) to the isocenter. Results: For each measurement, the H*(10) rate was relatively constant with increasing distance away from the isocenter with standard deviations on the order of a tenth of a mSv/h or less for the given beam energy. In general, fluctuations in the longitudinal H*(10) rate between the anterior-posterior couch directions were approximately a percent for both beam energies. Conclusion: Our preliminary results suggest an H*(10) rate of about 30 mSv/h (40 mSv/h) or less for TrueBeam (Varian Clinac 2100) for all measurements considered in this study indicating a relatively low contribution of produced secondary neutrons to the primary therapeutic beam.

  10. Role of quantum coherence in chromophoric energy transport

    E-Print Network [OSTI]

    Patrick Rebentrost; Masoud Mohseni; Alán Aspuru-Guzik

    2009-02-04

    The role of quantum coherence and the environment in the dynamics of excitation energy transfer is not fully understood. In this work, we introduce the concept of dynamical contributions of various physical processes to the energy transfer efficiency. We develop two complementary approaches, based on a Green's function method and energy transfer susceptibilities, and quantify the importance of the Hamiltonian evolution, phonon-induced decoherence, and spatial relaxation pathways. We investigate the Fenna-Matthews-Olson protein complex, where we find a contribution of coherent dynamics of about 10% and of relaxation of 80%.

  11. Low-temperature coherence properties of Z_2 quantum memory

    E-Print Network [OSTI]

    Tomoyuki Morimae

    2010-01-08

    We investigate low-temperature coherence properties of the Z_2 quantum memory which is capable of storing the information of a single logical qubit. We show that the memory has superposition of macroscopically distinct states for some values of a control parameter and at sufficiently low temperature, and that the code states of this memory have no instability except for the inevitable one. However, we also see that the coherence power of this memory is limited by space and time. We also briefly discuss the RVB memory, which is an improvement of the Z_2 quantum memory, and the relations of our results to the obscured symmetry breaking in statistical physics.

  12. Quatum Thermodynamics and the coherence in Ion channels

    E-Print Network [OSTI]

    Samyadeb Bhattacharya; Sisir Roy

    2013-05-02

    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.

  13. Generating polarization controllable FELs at Dalian coherent light source

    E-Print Network [OSTI]

    Zhang, T; Wang, D; Zhao, Z T; Zhang, W Q; Wu, G R; Dai, D X; Yang, X M

    2013-01-01

    The property of the FEL polarization is of great importance to the user community. FEL pulses with ultra-high intensity and flexible polarization control ability will absolutely open up new scientific realms. In this paper, several polarization control approaches are presented to investigate the great potential on Dalian coherent light source, which is a government-approved novel FEL user facility with the capability of wavelength continuously tunable in the EUV regime of 50-150 nm. The numerical simulations show that both circularly polarized FELs with highly modulating frequency and 100 microjoule level pulse energy could be generated at Dalian coherent light source.

  14. 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)

    2013-12-15

    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.

  15. 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

    2002-02-05

    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.

  16. Coherent anti-Stokes Raman scattering (CARS) optimized by exploiting optical interference 

    E-Print Network [OSTI]

    Wang, Xi

    2012-07-16

    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...

  17. Detecting and analyzing coherent structures in two-dimensional dynamical systems

    E-Print Network [OSTI]

    Allshouse, Michael R

    2013-01-01

    The identification of coherent structures enhances the understanding of transport by complex flows such as those found at the ocean surface. The rapidly developing approach of Lagrangian Coherent Structures (LCSs) is based ...

  18. Spectral/ Fourier domain Doppler Optical Coherence Tomography in the rodent retina

    E-Print Network [OSTI]

    Liu, Jonathan Jaoshin

    2008-01-01

    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 ...

  19. Endoscopic optical coherence tomography for clinical studies in the gastrointestinal tract

    E-Print Network [OSTI]

    Tsai, Tsung-Han, Ph. D. Massachusetts Institute of Technology

    2013-01-01

    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. ...

  20. A study of coherent nonlinear processes in dense media with continuous and pulsed laser fields 

    E-Print Network [OSTI]

    Zhang, Aihua

    2010-07-14

    Coherent nonlinear effects such as Electromagnetically Induced Transparency (EIT), Coherent Population Trapping (CPT), and Slow light are studied in thermal Rb vapor by both continuous and pulsed laser fields. This work primarily includes three...

  1. Compact laser-driven electron acceleration, bunch compression and coherent nonlinear Thomson scattering

    E-Print Network [OSTI]

    Wong, Liang Jie

    2013-01-01

    Coherent hard x-rays have many medical, commercial and academic research applications. To facilitate the design of a table-top coherent hard x-ray source, this thesis studies the linear acceleration of electrons by optical ...

  2. 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 ...

  3. Enhancement of field generation via maximal atomic coherence prepared by fast adiabatic passage in Rb vapor 

    E-Print Network [OSTI]

    Sautenkov, V. A.; Ye, C. Y.; Rostovtsev, Y. V.; Welch, George R.; Scully, Marlan O.

    2004-01-01

    We have experimentally demonstrated the enhancement of coherent Raman scattering in Rb atomic vapor by exciting maximal atomic coherence with fractional stimulated Raman adiabatic passage. Experimental results are in good agreement with numerical...

  4. Photonic Framework to Handle Physical and Chemical Processes: Quantum Entanglement, Coherence, De-coherence, Re-coherence and the Roles of Multipartite Base States

    E-Print Network [OSTI]

    Orlando Tapia

    2014-07-14

    A quantum framework, according quantum theories of electromagnetic (EM)radiation to matter response, leads to a handy scheme addressed to examine both physical and chemical processes. Fundamental quantum effects such asentanglement, coherence, de-coherence and re-coherence yield a fully quantum physical presentation applicable to chemical processes. A photonic basis-set obtains including all possibilities accessible to a system in abstract space; electronuclear (EN) base states put in resonance by photon fields are the ground where quantum states, q-states, would show time evolution. At laboratory space where energy and angular momentum conservation hold quantum dynamics (i.e. amplitude changes) is to be driven by low frequency EM radiation, e.g. microwaves. Materiality sustaining q-states unchanged.Here, focus on construction and reading of photonic quantum states that underlie a host of physical processes recently submitted to experimental examination. The approach moves away interpretational issues using classical physics language to focus on apprehending quantum states including experimental information.

  5. Final report: high resolution lensless 3D imaging of nanostructures with coherent x-rays

    SciTech Connect (OSTI)

    Jacobsen, Chris

    2014-12-07

    Final report on the project "High resolution lensless 3D imaging of nanostructures with coherent x-rays"

  6. Deep inference proof theory equals categorical proof theory minus coherence

    E-Print Network [OSTI]

    Pratt, Vaughan

    Deep inference proof theory equals categorical proof theory minus coherence DOMINIC J. D. HUGHES Stanford University October 6, 2004 Abstract This paper links deep inference proof theory, as studied by Guglielmi et al., to categorical proof theory in the sense of Lambek et al.. It observes how deep inference

  7. Efficient method for controlling the spatial coherence of a laser

    E-Print Network [OSTI]

    Cao, Hui

    variation in the total output power is presented. It is based on varying the diameter of a spatial filter from 1 to 320,000, with less than a 50% change in the total output power. We show that a degenerate- hibiting very high spatial coherence and thermal sources or light emitting diodes (LEDs) having very low

  8. Heterodyne coherent anti-Stokes Raman scattering (CARS) imaging

    E-Print Network [OSTI]

    Potma, Eric Olaf

    Heterodyne coherent anti-Stokes Raman scattering (CARS) imaging Eric O. Potma,* Conor L. Evans with heterodyne co- herent anti-Stokes Raman scattering (CARS) interferometric microscopy. This technique that is linear in the concentration of vibrational modes. We show that heterodyne CARS microscopy permits

  9. Phased laser array with tailored spectral and coherence properties

    DOE Patents [OSTI]

    Messerly, Michael J; Dawson, Jay W; Beach, Raymond J

    2014-05-20

    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.

  10. Generating Coherent Patterns of Activity from Chaotic Neural Networks

    E-Print Network [OSTI]

    Abbott, Laurence

    Neuron Article Generating Coherent Patterns of Activity from Chaotic Neural Networks David Sussillo be used to alter the chaotic activity of a recurrently connected neural network and generate complex but controlled outputs. Training a neural network is a process through which network parameters (typically

  11. Atomic coherences rephasing by rapid adiabatic passages for quantum storage

    E-Print Network [OSTI]

    Vallette, Bruno

    Atomic coherences rephasing by rapid adiabatic passages for quantum storage M. Bonarota, R Aimé Cotton, Orsay, France #12;Outline Brief introduction to quantum memories Novel quantum storage-earth ions Long T2 Long Tstock Solid matrix Immobility Inhomogeneous Broadband protocols broadening Storage

  12. BARIC STRUCTURES ON TRIANGULATED CATEGORIES AND COHERENT SHEAVES

    E-Print Network [OSTI]

    Achar, Pramod

    BARIC STRUCTURES ON TRIANGULATED CATEGORIES AND COHERENT SHEAVES PRAMOD N. ACHAR AND DAVID TREUMANN Abstract. We introduce the notion of a baric structure on a triangulated category, as an abstraction of S. Morel's weight truncation formalism for mixed -adic sheaves. We study these structures on the derived

  13. Generating coherent broadband continuum soft-x-ray radiation by

    E-Print Network [OSTI]

    Neumark, Daniel M.

    Generating coherent broadband continuum soft-x-ray radiation by attosecond ionization gating Thomas as the driver for high-harmonic generation that has a cosine-like electric field stabilized with respect the generation of broadband and tunable attosecond pulses. Instead of fixing the carrier-envelope phase

  14. 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

  15. 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

  16. Coherent Ray Tracing for Complex Light Transport Effects

    E-Print Network [OSTI]

    Columbia University

    soft shadows from area light sources, large ray packets for real-time Whitted ray tracing, and adaptive lighting, depth of field, motion blur, and diffuse inter-reflections. This is an adaptive Monte CarloCoherent Ray Tracing for Complex Light Transport Effects Ryan S. Overbeck Advised by: Ravi

  17. Lessons of Coherence and Decoherence--From Neutrinos to SQUIDS

    E-Print Network [OSTI]

    L. Stodolsky

    2002-06-21

    We indicate some of the lessons learned from our work on coherence and decoherence in various fields and mention some recent work with sold state devices as elements of the ``quantum computer'', including the realization of simple logic gates controlled by adiabatic processes. We correct a commonly held misconception concerning decoherence for a free particle.

  18. Optimal energy-preserving conversions of quantum coherence

    E-Print Network [OSTI]

    Yuxiang Yang; Giulio Chiribella

    2015-03-05

    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.

  19. 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

  20. Mass exchange in the stable boundary layer by coherent structures

    E-Print Network [OSTI]

    Leclerc, Monique Y.

    ) and a dense array of wind sensors to observe an indirect representation of roll vortices and plumes over the surface appears to pump energy near the surface thereby supporting the development of coherent structures gaseous exchange 1. Introduction Mass and energy exchange in the stable boundary layer remains poorly

  1. USING OPTICAL COHERENCE TOMOGRAPHY TO EXAMINE THE SUBSURFACE MORPHOLOGY OF

    E-Print Network [OSTI]

    Barton, Jennifer K.

    ), a new method for ceramics research, is a non-destructive, three-dimensional tomography system, which;However, optical coherence tomography (OCT) provides a non-destructive, three-dimensional technique and atmosphere controlled, cooling rates modified, additive experimental testing and other parameters measured

  2. Special Section Guest Editorial Coherent Raman Imaging Techniques and Biomedical

    E-Print Network [OSTI]

    Potma, Eric Olaf

    Special Section Guest Editorial Coherent Raman Imaging Techniques and Biomedical Applications. The combination of high resolution and molecular contrast has moved Raman techniques into the biomedical spotlight on biomedical imag- ing. The spontaneous Raman interaction is weak, yielding insufficient photons for fast

  3. 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

  4. OPTICAL COHERENCE TOMOGRAPHY PRINCIPLES, INSTRUMENTATION, AND BIOLOGICAL APPLICATONS

    E-Print Network [OSTI]

    Boppart, Stephen

    OPTICAL COHERENCE TOMOGRAPHY PRINCIPLES, INSTRUMENTATION, AND BIOLOGICAL APPLICATONS E.A. SW ANSON powerful medical diagnostic techniques,they are invasive and can be time consuming and costly. Furthermore. MIT has designed,developed,and fielded a clinical instrument that is now operating at the New England

  5. Phased laser array with tailored spectral and coherence properties

    DOE Patents [OSTI]

    Messerly, Michael J (Danville, CA); Dawson, Jay W (Livermore, CA); Beach, Raymond J (Livermore, CA)

    2011-03-29

    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.

  6. 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)

    2008-08-05

    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.

  7. Stimulated coherent anti-Stokes Raman spectroscopy (CARS) resonances originate from double-slit

    E-Print Network [OSTI]

    Mukamel, Shaul

    Stimulated coherent anti-Stokes Raman spectroscopy (CARS) resonances originate from double January 21, 2010 (received for review September 3, 2009) Coherent anti-Stokes Raman spectroscopy (CARS with re- spect to pulse parameters. CARS microscopy pulse shaping ultrafast spectroscpy Coherent Raman

  8. Asymptotic Analysis of Multivariate Coherent Risks lih@math.wsu.edu

    E-Print Network [OSTI]

    Li, Haijun

    Asymptotic Analysis of Multivariate Coherent Risks Haijun Li lih@math.wsu.edu Washington State Asymptotic Analysis of Multivariate Coherent Risks 7th MDA, 08/10/2010 1 / 22 #12;Outline 1 Coherent Risks Asymptotic Analysis of Tail Conditional Expectations Multivariate Regular Variation Tail Risk of Multivariate

  9. Why Gabor Frames? Two Fundamental Measures of Coherence and Their Role in Model Selection

    E-Print Network [OSTI]

    Bajwa, Waheed U.

    on Information Theory, Austin, TX, June 2010. WUB is with the Program in Applied and Computational Mathematics1 Why Gabor Frames? Two Fundamental Measures of Coherence and Their Role in Model Selection Waheed and introduces two fundamental measures of coherence--termed as the worst-case coherence and the average

  10. Phase-locked laser system for use in atomic coherence experiments Alberto M. Marinoa

    E-Print Network [OSTI]

    Stroud Jr., Carlos R.

    Phase-locked laser system for use in atomic coherence experiments Alberto M. Marinoa and C. R-coherent laser system designed for use in experiments involving coherently prepared atomic media. We implement operating around 795 nm. A low-power laser serves as a frequency reference for two high-power lasers which

  11. Scientific Impact

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDidDevelopment Top Scientific Impact Since its inception over twenty

  12. Momentum dissipation and effective theories of coherent and incoherent transport

    E-Print Network [OSTI]

    Richard A. Davison; Blaise Goutéraux

    2015-01-21

    We study heat transport in two systems without momentum conservation: a hydrodynamic system, and a holographic system with spatially dependent, massless scalar fields. When momentum dissipates slowly, there is a well-defined, coherent collective excitation in the AC heat conductivity, and a crossover between sound-like and diffusive transport at small and large distance scales. When momentum dissipates quickly, there is no such excitation in the incoherent AC heat conductivity, and diffusion dominates at all distance scales. For a critical value of the momentum dissipation rate, we compute exact expressions for the Green's functions of our holographic system due to an emergent gravitational self-duality, similar to electric/magnetic duality, and SL(2,R) symmetries. We extend the coherent/incoherent classification to examples of charge transport in other holographic systems: probe brane theories and neutral theories with non-Maxwell actions.

  13. Development of coherent Raman measurements of temperature in condensed phases

    SciTech Connect (OSTI)

    Mcgrane, Shawn D; Dang, Nhan C; Bolme, Cindy A; Moore, David S

    2010-12-08

    We report theoretical considerations and preliminary data on various forms of coherent Raman spectroscopy that have been considered as candidates for measurement of temperature in condensed phase experiments with picosecond time resolution. Due to the inherent broadness and congestion of vibrational features in condensed phase solids, particularly at high temperatures and pressures, only approaches that rely on the ratio of anti-Stokes to Stokes spectral features are considered. Methods that rely on resolution of vibrational progressions, calibration of frequency shifts with temperature and pressure in reference experiments, or detailed comparison to calculation are inappropriate or impossible for our applications. In particular, we consider femtosecond stimulated Raman spectroscopy (FSRS), femtosecond/picosecond hybrid coherent Raman spectroscopy (multiplex CARS), and optical heterodyne detected femtosecond Raman induced Kerr Effect spectroscopy (OHD-FRIKES). We show that only FSRS has the ability to measure temperature via an anti-Stokes to Stokes ratio of peaks.

  14. High-Temperature Quantum Coherence from Dissipative Environments

    E-Print Network [OSTI]

    George E. Cragg

    2014-11-14

    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.

  15. Coherence properties of nanofiber-trapped cesium atoms

    E-Print Network [OSTI]

    Reitz, D; Mitsch, R; Schneeweiss, P; Rauschenbeutel, A

    2013-01-01

    We experimentally study the ground state coherence properties of cesium atoms in a nanofiber-based two-color dipole trap, localized 200 nm away from the fiber surface. Using microwave radiation to coherently drive the clock transition, we record Ramsey fringes as well as spin echo signals and infer a reversible dephasing time $T_2^\\ast=0.6$ ms and an irreversible dephasing time $T_2^\\prime=3.7$ ms. By theoretically modelling the signals, we find that, for our experimental parameters, $T_2^\\ast$ and $T_2^\\prime$ are limited by the finite initial temperature of the atomic ensemble and the heating rate, respectively. Our results represent a fundamental step towards establishing nanofiber-based traps for cold atoms as a building block in an optical fiber quantum network.

  16. Coherence properties of nanofiber-trapped cesium atoms

    E-Print Network [OSTI]

    D. Reitz; C. Sayrin; R. Mitsch; P. Schneeweiss; A. Rauschenbeutel

    2013-03-28

    We experimentally study the ground state coherence properties of cesium atoms in a nanofiber-based two-color dipole trap, localized 200 nm away from the fiber surface. Using microwave radiation to coherently drive the clock transition, we record Ramsey fringes as well as spin echo signals and infer a reversible dephasing time $T_2^\\ast=0.6$ ms and an irreversible dephasing time $T_2^\\prime=3.7$ ms. By theoretically modelling the signals, we find that, for our experimental parameters, $T_2^\\ast$ and $T_2^\\prime$ are limited by the finite initial temperature of the atomic ensemble and the heating rate, respectively. Our results represent a fundamental step towards establishing nanofiber-based traps for cold atoms as a building block in an optical fiber quantum network.

  17. Coherent control of photocurrent in a disordered photovoltaic system

    E-Print Network [OSTI]

    Liew, Seng Fatt; Sheehan, Stafford W; Goetschy, Arthur; Schmuttenmaer, Charles A; Stone, A Douglas; Cao, Hui

    2015-01-01

    Optical absorption is commonly considered an intrinsic property of a medium, independent of the details of the illumination source. However, for a spatially coherent illumination of a disordered medium, interference effects can modify the spatial distribution of light inside the medium, allowing the global or local absorption to be tuned by adjusting an input beam's spatial characteristics. Here we demonstrate the coherent control of absorption by using the wavefront shaping technique to modulate photocurrent in a dye-sensitized solar cell. The incident wavefront of a laser beam is optimized to concentrate light near the front side of the porous photoanode where the collection efficiency of photo-generated electrons is highest. Destructive interference reduces light leakage through open boundaries, facilitating light absorption and conversion to current. This technique provides a powerful tool for probing and controlling photochemical processes inside nominally opaque media by manipulating the internal spatia...

  18. Quantum Coherence between Two Atoms beyond Q=10{sup 15}

    SciTech Connect (OSTI)

    Chou, C. W.; Hume, D. B.; Thorpe, M. J.; Wineland, D. J.; Rosenband, T. [Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

    2011-04-22

    We place two atoms in quantum superposition states and observe coherent phase evolution for 3.4x10{sup 15} cycles. Correlation signals from the two atoms yield information about their relative phase even after the probe radiation has decohered. This technique allowed a frequency comparison of two {sup 27}Al{sup +} ions with fractional uncertainty 3.7{sub -0.8}{sup +1.0}x10{sup -16}/{radical}({tau}/s). Two measures of the Q factor are reported: The Q factor derived from quantum coherence is 3.4{sub -1.1}{sup +2.4}x10{sup 16}, and the spectroscopic Q factor for a Ramsey time of 3 s is 6.7x10{sup 15}. We demonstrate a method to detect the individual quantum states of two Al{sup +} ions in a Mg{sup +}-Al{sup +}-Al{sup +} linear ion chain without spatially resolving the ions.

  19. Apparatus for generating coherent infrared energy of selected wavelength

    DOE Patents [OSTI]

    Stevens, Charles G. (Danville, CA)

    1985-01-01

    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).

  20. Few-photon coherent nonlinear optics with a single molecule

    E-Print Network [OSTI]

    Maser, Andreas; Utikal, Tobias; Götzinger, Stephan; Sandoghdar, Vahid

    2015-01-01

    The pioneering experiments of linear spectroscopy were performed using flames in the 1800s, but nonlinear optical measurements had to wait until lasers became available in the twentieth century. Because the nonlinear cross section of materials is very small, usually macroscopic bulk samples and pulsed lasers are used. Numerous efforts have explored coherent nonlinear signal generation from individual nanoparticles or small atomic ensembles with millions of atoms. Experiments on a single semiconductor quantum dot have also been reported, albeit with a very small yield. Here, we report on coherent nonlinear spectroscopy of a single molecule under continuous-wave single-pass illumination, where efficient photon-molecule coupling in a tight focus allows switching of a laser beam by less than a handful of pump photons nearly resonant with the sharp molecular transition. Aside from their fundamental importance, our results emphasize the potential of organic molecules for applications such as quantum information pro...

  1. Reduced Generalization in Autism: An Alternative to Weak Central Coherence

    E-Print Network [OSTI]

    Plaisted, Kate C.

    2015-06-24

    Generalization in Autism: An Alternative to Weak Central Coherence Kate C. Plaisted This chapter appeared in: “The development of Autism: Perspectives from Theory and Research” (2001) Eds :Jacob A. Burack, Tony Charman... , Nurit Yirmiya & Philip R. Zelazo Lawrence Erlbaum Associates, Inc, Publishers. (p 149-169) KC Plaisted-Grant 2015 It has long been observed that individuals with autism exhibit peculiar attentional and perceptual abnormalities...

  2. Capacity with energy constraint in coherent state channel

    E-Print Network [OSTI]

    Masahito Hayashi

    2009-04-02

    We consider two kind of energy constraints when the output state is a coherent state. One is a constraint on the total energy during a fixed period; the other is a constraint on the total energy for a single code. The first setting can be easily dealt with by using the conventional capacity formula. The second setting requires the general capacity formula for a classical-quantum channel.

  3. On Quantum Coherence Effects in Photo and Solar Cells

    E-Print Network [OSTI]

    Kimberly Chapin; Konstantin Dorfman; Anatoly Svidzinsky; Marlan Scully

    2011-02-01

    We show that quantum coherence can increase the quantum efficiency of various thermodynamic systems. For example, we can enhance the quantum efficiency for a quantum dot photocell, a laser based solar cell and the photo-Carnot quantum heat engine. Our results are fully consistent with the laws of thermodynamics contrary to comments found in the paper of A.P. Kirk, Phys. Rev. Lett. 106, 048703 (2011).

  4. Environmental Assessment for the proposed Induction Linac System Experiments in Building 51B at Lawrence Berkeley National Laboratory, Berkeley, California

    SciTech Connect (OSTI)

    NONE

    1995-08-01

    The US Department of Energy (DOE) has prepared an Environmental Assessment (EA), (DOE/EA-1087) evaluating the proposed action to modify existing Building 51B at Lawrence Berkeley National Laboratory (LBNL) to install and conduct experiments on a new Induction Linear Accelerator System. LBNL is located in Berkeley, California and operated by the University of California (UC). The project consists of placing a pre-fabricated building inside Building 51B to house a new 10 MeV heavy ion linear accelerator. A control room and other support areas would be provided within and directly adjacent to Building 51B. The accelerator system would be used to conduct tests, at reduced scale and cost, many features of a heavy-ion accelerator driver for the Department of Energy`s inertial fusion energy program. Based upon information and analyses in the EA, the DOE has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act of 1969. Therefore, an Environmental Impact Statement is not required. This report contains the Environmental Assessment, as well as the Finding of No Significant Impact (FONSI).

  5. Energy dissipation in magnetohydrodynamic turbulence: coherent structures or 'nanoflares'?

    SciTech Connect (OSTI)

    Zhdankin, Vladimir; Boldyrev, Stanislav; Perez, Jean Carlos; Tobias, Steven M.

    2014-11-10

    We investigate the intermittency of energy dissipation in magnetohydrodynamic (MHD) turbulence by identifying dissipative structures and measuring their characteristic scales. We find that the probability distribution of energy dissipation rates exhibits a power-law tail with an index very close to the critical value of –2.0, which indicates that structures of all intensities contribute equally to energy dissipation. We find that energy dissipation is uniformly spread among coherent structures with lengths and widths in the inertial range. At the same time, these structures have thicknesses deep within the dissipative regime. As the Reynolds number is increased, structures become thinner and more numerous, while the energy dissipation continues to occur mainly in large-scale coherent structures. This implies that in the limit of high Reynolds number, energy dissipation occurs in thin, tightly packed current sheets which nevertheless span a continuum of scales up to the system size, exhibiting features of both coherent structures and nanoflares previously conjectured as a coronal heating mechanism.

  6. The COHERENT Experiment at the Spallation Neutron Source

    E-Print Network [OSTI]

    Akimov, D; Awe, C; Barbeau, P S; Barton, P; Becker, B; Below, V; Bolozdynya, A; Burenkov, A; Cabrera-Palmer, B; Collar, J I; Cooper, R J; Cooper, R L; Cuesta, C; Dean, D; Detwiler, J; Efremenko, Y; Elliott, S R; Fields, N; Fox, W; Galindo-Uribarri, A; Green, M; Heath, M; Hedges, S; Herman, N; Hornback, D; Iverson, E B; Kaufman, L; Klein, S R; Khromov, A; Konovalev, A; Kumpan, A; Leadbetter, C; Li, L; Lu, W; Melikyan, A; Markoff, D; Miller, K; Middlebrook, M; Mueller, P; Naumov, P; Newby, J; Parno, D; Penttila, S; Perumpilly, G; Radford, D; Ray, H; Raybern, J; Reyna, D; Rich, G C; Rimal, D; Rudik, D; Scholberg, K; Scholz, B; Snow, W M; Sosnovchev, A; Shakirov, A; Suchyta, S; Suh, B; Tayloe, R; Thornton, R T; Tolstukhin, A; Vetter, K; Yu, C H

    2015-01-01

    The COHERENT collaboration's primary objective is to measure coherent elastic neutrino-nucleus scattering (CEvNS) using the unique, high-quality source of tens-of-MeV neutrinos provided by the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). In spite of its large cross section, the CEvNS process has never been observed, due to tiny energies of the resulting nuclear recoils which are out of reach for standard neutrino detectors. The measurement of CEvNS has now become feasible, thanks to the development of ultra-sensitive technology for rare decay and weakly-interacting massive particle (dark matter) searches. The CEvNS cross section is cleanly predicted in the standard model; hence its measurement provides a standard model test. It is relevant for supernova physics and supernova-neutrino detection, and enables validation of dark-matter detector background and detector-response models. In the long term, precision measurement of CEvNS will address questions of nuclear structure. COHERENT...

  7. Emergence of coherence in the charge-density wave state of 2H-NbSe2

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

    Chatterjee, U.; Zhao, J.; Iavarone, M.; Di Capua, R.; Castellan, J. P.; Karapetrov, G.; Malliakas, C. D.; Kanatzidis, M. G.; Claus, H.; Ruff, J. P. C.; et al

    2015-02-17

    A charge-density wave (CDW) state has a broken symmetry described by a complex order parameter with an amplitude and a phase. The conventional view, based on clean, weak-coupling systems, is that a finite amplitude and long-range phase coherence set in simultaneously at the CDW transition temperature Tcdw. Here we investigate, using photoemission, X-ray scattering and scanning tunnelling microscopy, the canonical CDW compound 2H-NbSe2 intercalated with Mn and Co, and show that the conventional view is untenable. We find that, either at high temperature or at large intercalation, CDW order becomes short-ranged with a well-defined amplitude, which has impacts on themore »electronic dispersion, giving rise to an energy gap. The phase transition at Tcdw marks the onset of long-range order with global phase coherence, leading to sharp electronic excitations. Our observations emphasize the importance of phase fluctuations in strongly coupled CDW systems and provide insights into the significance of phase incoherence in ‘pseudogap’ states.« less

  8. Partial angular coherence and the angular Schmidt spectrum of entangled two-photon fields

    SciTech Connect (OSTI)

    Jha, Anand Kumar; Boyd, Robert W. [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Agarwal, Girish S. [Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078 (United States)

    2011-12-15

    We study partially coherent fields that have a coherent-mode representation in the orbital-angular-momentum-mode basis. For such fields, we introduce the concepts of the angular coherence function and the coherence angle. Such fields are naturally produced by the process of parametric down-conversion--a second-order nonlinear optical process in which a pump photon breaks up into two entangled photons, known as the signal and idler photons. We show that the angular coherence functions of the signal and idler fields are directly related to the angular Schmidt (spiral) spectrum of the down-converted two-photon field and thus that the angular Schmidt spectrum can be measured directly by measuring the angular coherence function of either the signal or the idler field, without requiring coincidence detection.

  9. Thermal-Light-Induced Coherent Dynamics in Atoms and Molecules -- an Exact Quantum Mechanical Treatment

    E-Print Network [OSTI]

    David Avisar; Asaf Eilam; A. D. Wilson-Gordon

    2015-05-01

    The question of whether sunlight induces coherent dynamics in biological systems is under debate. Here we show, on the basis of an exact fully quantum mechanical treatment, that thermal light induces excited-state coherences in matter similar to those induced by a coherent state. We demonstrate the phenomenon on a V-type model system and a two-state Born-Oppenheimer molecular system. Remarkably, wavepacket-like dynamics is induced in the excited molecular potential-energy surface.

  10. Glucose concentration measured by the hybrid coherent anti-Stokes Raman-scattering technique 

    E-Print Network [OSTI]

    Wang, Xi; Zhang, Aihua; Zhi, Miaochan; Sokolov, Alexei V.; Welch, George R.

    2010-01-01

    spectroscopy and coherent anti-Stokes Raman-scattering (CARS) spectroscopy find widespread use in medical diagnostics [3,4]. While the probability of spontaneous Raman scattering depends on the molecular concentration linearly, for its coherent counterpart?CARS...?the signal is known to scale quadrat- ically with the concentration of scatterers due to constructive interference of the resultant coherent photons [1,2]. In recent work, Dogariu et al. [5] have measured a clear quadratic dependence of the CARS signal...

  11. Economic Assessment Environmental impact

    E-Print Network [OSTI]

    - ". Economic Assessment Environmental impact Statement NESHAPS for Radionuclides Background Economic Assessment Environmental Impact Statement for NESHAPS Radionuclides VOLUME 3 BACKGROUND Standards for Hazardous Air Pollutants (NESHAPs) for Radionuclides. An Environmental Impact Statement (EIS

  12. Impact Cratering and Post-impact Sedimentation

    E-Print Network [OSTI]

    Torsvik, Trond Helge

    Chapter 5 Impact Cratering and Post-impact Sedimentation Henning Dypvik, Morten Smelror, Atle Mørk; Dypvik and Attrep 1999; Sandbakken 2002) (see Figs. 6.2 and 6.3). In this chapter the Mjølnir core (7329-0316 Oslo, Norway e-mail: henning.dypvik@geo.uio.no 139H. Dypvik et al. (eds.), The Mjølnir Impact

  13. Comment on "Analysis of quantum coherent semiconductor quantum dot p-i-n junction photovoltaic cells"

    E-Print Network [OSTI]

    Scully, Marlan O

    2010-01-01

    This is a comment on PRL paper by A.P. Kirk "Analysis of quantum coherent semiconductor quantum dot p-i-n junction photovoltaic cells"

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

    E-Print Network [OSTI]

    Knyazik, Andrey

    2013-01-01

    Khamitova. Utilization of photon orbital angular momentum inof Coherent Broadband Photon Pulses with a Cascadedfree-electron laser. Nat Photon, 4(9):641647, 2010. [6] L.

  15. Time-Resolved Picosecond Pure-Rotational Coherent anti-Stokes...

    Office of Scientific and Technical Information (OSTI)

    Coherent anti-Stokes Raman Spectroscopy for Thermometry and Species Concentration in Combustion Environments. Citation Details In-Document Search Title: Time-Resolved Picosecond...

  16. Method and apparatus for single-stepping coherence events in a multiprocessor system under software control

    DOE Patents [OSTI]

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

    2010-11-02

    An apparatus and method are disclosed for single-stepping coherence events in a multiprocessor system under software control in order to monitor the behavior of a memory coherence mechanism. Single-stepping coherence events in a multiprocessor system is made possible by adding one or more step registers. By accessing these step registers, one or more coherence requests are processed by the multiprocessor system. The step registers determine if the snoop unit will operate by proceeding in a normal execution mode, or operate in a single-step mode.

  17. Tunable excitation source for coherent Raman spectroscopy based on a single fiber laser

    E-Print Network [OSTI]

    Adany, Peter; Arnett, David C.; Johnson, Carey K.; Hui, Rongqing

    2011-10-01

    We demonstrate a wavelength tunable optical excitation source for coherent Raman scattering (CRS) spectroscopy based on a single femtosecondfiber laser. Electrically controlled wavelength tuning of Stokes optical pulses ...

  18. Measurement of radiation coherence by means of interference visibility in the reflected light

    E-Print Network [OSTI]

    Tikhonov, E A

    2015-01-01

    Proposed, justified and tested measuring of beam spatial coherence, based on the detection of an interference visibility of the equal to intensity of beam replicas emerging under reflection from the rotated plane-parallel plate. The method consists in measuring the interference contrast at the simultaneous change of the longitudinal path difference and transverse shift of named replicas. Accurate measurement of the angle of rotated plate and the amplitude distribution of interferential minimaxes allows to determine the width of the beam spatial coherence. Spatial coherence of some types of multimode lasers has been measured by the method. Keywords: coherence measurements, interference in 2 move apart beam, rotable interferometer

  19. Observed limiting cases of horizontal field coherence and array performance in a

    E-Print Network [OSTI]

    the Shallow-Water 2006 (SW06) field program2 are used here to measure coherence. As part of the experiment

  20. Efficient Energy Transport in Photosynthesis: Roles of Coherence and Entanglement

    E-Print Network [OSTI]

    Apoorva D. Patel

    2011-04-07

    Recently it has been discovered---contrary to expectations of physicists as well as biologists---that the energy transport during photosynthesis, from the chlorophyll pigment that captures the photon to the reaction centre where glucose is synthesised from carbon dioxide and water, is highly coherent even at ambient temperature and in the cellular environment. This process and the key molecular ingredients that it depends on are described. By looking at the process from the computer science view-point, we can study what has been optimised and how. A spatial search algorithmic model based on robust features of wave dynamics is presented.

  1. Coherent heteronuclear spin dynamics in an ultracold spin-1 mixture

    E-Print Network [OSTI]

    Li, Xiaoke; He, Xiaodong; Wang, Fudong; Guo, Mingyang; Xu, Zhi-Fang; Zhang, Shizhong; Wang, Dajun

    2015-01-01

    We report the observation of coherent heteronuclear spin dynamics driven by inter-species spin-spin interaction in an ultracold spinor mixture, which manifests as periodical and well correlated spin oscillations between two atomic species. In particular, we investigate the magnetic field dependence of the oscillations and find a resonance behavior which depends on {\\em both} the linear and quadratic Zeeman effects and the spin-dependent interaction. We also demonstrate a unique knob for controlling the spin dynamics in the spinor mixture with species-dependent vector light shifts. Our finds are in agreement with theoretical simulations without any fitting parameters.

  2. Broadband Coherent Enhancement of Transmission and Absorption in Disordered Media

    E-Print Network [OSTI]

    Hsu, Chia Wei; Bromberg, Yaron; Stone, A Douglas; Cao, Hui

    2015-01-01

    We study the optimal diffusive transmission and absorption of broadband or polychromatic light in a disordered medium. By introducing matrices describing broadband transmission and reflection, we formulate an extremal eigenvalue problem where the optimal input wavefront is given by the corresponding eigenvector. We show analytically that a single wavefront can exhibit strongly enhanced total transmission or total absorption across a bandwidth that is orders of magnitude broader than the spectral correlation width of the medium, due to long-range correlations in coherent diffusion. We find excellent agreement between the analytic theory and numerical simulations.

  3. Coherent electron cooling proof of principle instrumentation design

    SciTech Connect (OSTI)

    Gassner D. M.; Litvinenko, V.; Michnoff, R.; Miller, T.; Minty, M.; Pinayev, I.

    2012-04-15

    The goal of the Coherent Electron Cooling Proof-of-Principle (CeC PoP) experiment being designed at RHIC is to demonstrate longitudinal (energy spread) cooling before the expected CD-2 for eRHIC. The scope of the experiment is to longitudinally cool a single bunch of 40 GeV/u gold ions in RHIC. This paper will describe the instrumentation systems proposed to meet the diagnostics challenges. These include measurements of beam intensity, emittance, energy spread, bunch length, position, orbit stability, and transverse and temporal alignment of electron and ion beams.

  4. Attraction-Based Computation of Hyperbolic Lagrangian Coherent Structures

    E-Print Network [OSTI]

    Daniel Karrasch; Mohammad Farazmand; George Haller

    2014-10-23

    Recent advances enable the simultaneous computation of both attracting and repelling families of Lagrangian Coherent Structures (LCS) at the same initial or final time of interest. Obtaining LCS positions at intermediate times, however, has been problematic, because either the repelling or the attracting family is unstable with respect to numerical advection in a given time direction. Here we develop a new approach to compute arbitrary positions of hyperbolic LCS in a numerically robust fashion. Our approach only involves the advection of attracting material surfaces, thereby providing accurate LCS tracking at low computational cost. We illustrate the advantages of this approach on a simple model and on a turbulent velocity data set.

  5. Influence of pulse width and detuning on coherent phonon generation

    E-Print Network [OSTI]

    Nakamura, Kazutaka G; Kayanuma, Yosuke

    2015-01-01

    We investigated the coherent phonon generation mechanism by irradiation of an ultrashort pulse with a simple two-level model. Our derived formulation shows that both impulsive stimulated Raman scattering (ISRS) and impulsive absorption (IA) simultaneously occur, and phonon wave packets are generated in the electronic ground and excited states by ISRS and IA, respectively. We identify the dominant process from the amplitude of the phonon oscillation. For short pulse widths, ISRS is very small and becomes larger as the pulse width increases. We also show that the initial phase is dependent on the pulse width and the detuning.

  6. Coherent manipulation of a Majorana qubit by a mechanical resonator

    E-Print Network [OSTI]

    P. Zhang; Franco Nori

    2015-08-24

    We propose a hybrid system composed of a Majorana qubit and a nanomechanical resonator, implemented by a spin-orbit-coupled superconducting nanowire, using a set of static and oscillating ferromagnetic gates. The ferromagnetic gates induce Majorana bound states in the nanowire, which hybridize and constitute a Majorana qubit. Due to the oscillation of one of these gates, the Majorana qubit can be coherently rotated. By tuning the gate voltage to modulate the local spin-orbit coupling, it is possible to reach the resonance of the qubit-oscillator system for relatively strong couplings.

  7. Research Program towards Observation of Neutrino-Nucleus Coherent Scattering

    E-Print Network [OSTI]

    Henry T. Wong

    2006-09-15

    The article describes the research program pursued by the TEXONO Collaboration towards an experiment to observe coherent scattering between neutrinos and the nucleus at the power reactor. The motivations of studying this process are surveyed. In particular, a threshold of 100-200 eV has been achieved with an ultra-low-energy germanium detector prototype. This detection capability at low energy can also be adapted to conduct searches of Cold Dark Matter in the low-mass region as well as to enhance the sensitivities in the study of neutrino magnetic moments.

  8. Fiber optic based optical coherence tomography (OCT) for dental applications

    SciTech Connect (OSTI)

    Everett, M. J., LLNL

    1998-06-02

    We have developed a hand-held fiber optic based optical coherence tomography (OCT) system for scanning of the oral cavity We have produced, using this scanning device, in viva cross-sectional images of hard and soft dental tissues in human volunteers Clinically relevant anatomical structures, including the gingival margin, periodontal sulcus, and dento-enamel junction, were visible in all the images The dento-enamel junction and the alveolar bone were identifiable in approximately two thirds of the images These images represent, to our knowledge, the first in viva OCT images of human dental tissue.

  9. Polaron Coherence Condensation in Layered Colossal Resistive Manganites

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access| DepartmentPeerFederalPlatinumtakePolaron Coherence Condensation in

  10. Polaron Coherence Condensation in Layered Colossal Resistive Manganites

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access| DepartmentPeerFederalPlatinumtakePolaron Coherence Condensation

  11. Polaron Coherence Condensation in Layered Colossal Resistive Manganites

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access| DepartmentPeerFederalPlatinumtakePolaron Coherence

  12. Long-range coherent energy transport in Photosystem II

    E-Print Network [OSTI]

    Jan J. J. Roden; Doran I. G. Bennett; K. Birgitta Whaley

    2015-01-27

    We simulate the long-range inter-complex electronic energy transfer in Photosystem II -- from the antenna complex, via a core complex, to the reaction center -- using a non-Markovian (ZOFE) quantum master equation description that allows us to quantify the electronic coherence involved in the energy transfer. We identify the pathways of the energy transfer in the network of coupled chromophores, using a description based on excitation probability currents. We investigate how the energy transfer depends on the initial excitation -- localized, coherent initial excitation versus delocalized, incoherent initial excitation -- and find that the energy transfer is remarkably robust with respect to such strong variations of the initial condition. To explore the importance of vibrationally enhanced transfer and to address the question of optimization in the system parameters, we vary the strength of the coupling between the electronic and the vibrational degrees of freedom. We find that the original parameters lie in a (broad) region that enables optimal transfer efficiency, and that the energy transfer appears to be very robust with respect to variations in the vibronic coupling. Nevertheless, vibrationally enhanced transfer appears to be crucial to obtain a high transfer efficiency. We compare our quantum simulation to a "classical" rate equation based on a modified-Redfield/generalized-F\\"orster description that was previously used to simulate energy transfer dynamics in the entire Photosystem II complex, and find very good agreement between quantum and rate-equation simulation of the overall energy transfer dynamics.

  13. Cavity-based architecture to preserve quantum coherence and entanglement

    E-Print Network [OSTI]

    Zhong-Xiao Man; Yun-Jie Xia; Rosario Lo Franco

    2015-08-07

    Quantum technology relies on the utilization of resources, like quantum coherence and entanglement, which allow quantum information and computation processing. This achievement is however jeopardized by the detrimental effects of the environment surrounding any quantum system, so that finding strategies to protect quantum resources is essential. Non-Markovian and structured environments are useful tools to this aim. Here we show how a simple environmental architecture made of two coupled lossy cavities enables a switch between Markovian and non-Markovian regimes for the dynamics of a qubit embedded in one of the cavity. Furthermore, qubit coherence can be indefinitely preserved if the cavity without qubit is perfect. We then focus on entanglement control of two independent qubits locally subject to such an engineered environment and discuss its feasibility in the framework of circuit quantum electrodynamics. With up-to-date experimental parameters, we show that our architecture allows entanglement lifetimes orders of magnitude longer than the spontaneous lifetime without local cavity couplings. This cavity-based architecture is straightforwardly extendable to many qubits for scalability.

  14. A passive transmitter for quantum key distribution with coherent light

    E-Print Network [OSTI]

    Marcos Curty; Marc Jofre; Valerio Pruneri; Morgan W. Mitchell

    2011-08-03

    Signal state preparation in quantum key distribution schemes can be realized using either an active or a passive source. Passive sources might be valuable in some scenarios; for instance, in those experimental setups operating at high transmission rates, since no externally driven element is required. Typical passive transmitters involve parametric down-conversion. More recently, it has been shown that phase-randomized coherent pulses also allow passive generation of decoy states and Bennett-Brassard 1984 (BB84) polarization signals, though the combination of both setups in a single passive source is cumbersome. In this paper, we present a complete passive transmitter that prepares decoy-state BB84 signals using coherent light. Our method employs sum-frequency generation together with linear optical components and classical photodetectors. In the asymptotic limit of an infinite long experiment, the resulting secret key rate (per pulse) is comparable to the one delivered by an active decoy-state BB84 setup with an infinite number of decoy settings.

  15. High photon flux table-top coherent extreme ultraviolet source

    E-Print Network [OSTI]

    Hädrich, Steffen; Rothhardt, Jan; Krebs, Manuel; Hoffmann, Armin; Pronin, Oleg; Pervak, Vladimir; Limpert, Jens; Tünnermann, Andreas

    2014-01-01

    High harmonic generation (HHG) enables extreme ultraviolet radiation with table-top setups. Its exceptional properties, such as coherence and (sub)-femtosecond pulse durations, have led to a diversity of applications. Some of these require a high photon flux and megahertz repetition rates, e.g. to avoid space charge effects in photoelectron spectroscopy. To date this has only been achieved with enhancement cavities. Here, we establish a novel route towards powerful HHG sources. By achieving phase-matched HHG of a megahertz fibre laser we generate a broad plateau (25 eV - 40 eV) of strong harmonics, each containing more than $10^{12}$ photons/s, which constitutes an increase by more than one order of magnitude in that wavelength range. The strongest harmonic (H25, 30 eV) has an average power of 143 $\\mu$W ($3\\cdot10^{13}$ photons/s). This concept will greatly advance and facilitate applications in photoelectron or coincidence spectroscopy, coherent diffractive imaging or (multidimensional) surface science.

  16. Coherent versus measurement feedback: Linear systems theory for quantum information

    E-Print Network [OSTI]

    Naoki Yamamoto

    2014-10-10

    To control a quantum system via feedback, we generally have two options in choosing control scheme. One is the coherent feedback, which feeds the output field of the system, through a fully quantum device, back to manipulate the system without involving any measurement process. The other one is the measurement-based feedback, which measures the output field and performs a real-time manipulation on the system based on the measurement results. Both schemes have advantages/disadvantages, depending on the system and the control goal, hence their comparison in several situation is important. This paper considers a general open linear quantum system with the following specific control goals; back-action evasion (BAE), generation of a quantum non-demolished (QND) variable, and generation of a decoherence-free subsystem (DFS), all of which have important roles in quantum information science. Then some no-go theorems are proven, clarifying that those goals cannot be achieved by any measurement-based feedback control. On the other hand it is shown that, for each control goal, there exists a coherent feedback controller accomplishing the task. The key idea to obtain all the results is system theoretic characterizations of BAE, QND, and DFS in terms of controllability and observability properties or transfer functions of linear systems, which are consistent with their standard definitions.

  17. Biophotons, coherence and photocount statistics: a critical review

    E-Print Network [OSTI]

    Michal Cifra; Christian Brouder; Michaela Nerudová; Ond?ej Ku?era

    2015-02-25

    Biological samples continuously emit ultra-weak photon emission (UPE, or "biophotons") which stems from electronic excited states generated chemically during oxidative metabolism and stress. Thus, UPE can potentially serve as a method for non-invasive diagnostics of oxidative processes or, if discovered, also of other processes capable of electron excitation. While the fundamental generating mechanisms of UPE are fairly elucidated together with their approximate ranges of intensities and spectra, statistical properties of UPE is still a highly challenging topic. Here we review claims about nontrivial statistical properties of UPE, such as coherence and squeezed states of light. After introduction to the necessary theory, we categorize the experimental works of all authors to those with solid, conventional interpretation and those with unconventional and even speculative interpretation. The conclusion of our review is twofold; while the phenomenon of UPE from biological systems can be considered experimentally well established, no reliable evidence for the coherence or nonclassicality of UPE was actually achieved up to now. Furthermore, we propose perspective avenues in the research of statistical properties of biological UPE.

  18. Coherent-Light Boosted, Super-Sensitive, Quantum Interferometry

    E-Print Network [OSTI]

    William N. Plick; Jonathan P. Dowling; G. S. Agarwal

    2015-06-14

    We present in this letter a scheme for optical interferometry. We utilize coherent-beam-stimulated two-mode squeezed light, which interacts with a phase shifter and is then squeezed again before detection. Our theoretical device has the potential to reach far below the shot noise limit (SNL) in phase sensitivity. This new proposal avoids the pitfalls of other setups, such as difficulty in creating the required resource. Furthermore, our scheme requires no complicated detection protocol, relying instead only on simple intensity measurement. Also, bright, coherent sources "boost" squeezed light, creating a very sensitive device. This hybrid scheme relies on no unknown components and can be constructed with current technology. In the following we present our analysis of this relatively straightforward device, using the operator propagation method. We derive the phase sensitivity and provide a simple numerical example of the power of our new proposal. Sensitivity scales as a shot noise limited Mach-Zehnder Interferometer, multiplied by a sub-Heisenberg contribution from the squeezed light.

  19. Atomic Resolution Coherent Diffractive Imaging and Ultrafast Science

    SciTech Connect (OSTI)

    Zuo, Jian-min (University of Illinois) [University of Illinois

    2011-01-12

    A major scientific challenge is determining the 3-D atomic structure of small nanostructures, including single molecules. Coherent diffractive imaging (CDI) is a promising approach. Recent progress has demonstrated coherent diffraction patterns can be recorded from individual nanostructures and phased to reconstruct their structure. However, overcoming the dose limit imposed by radiation damage is a major obstacle toward the full potential of CDI. One approach is to use ultrafast x-ray or electron pulses. In electron diffraction, amplitudes recorded in a diffraction pattern are unperturbed by lens aberrations, defocus, and other microscope resolution-limiting factors. Sub-A signals are available beyond the information limit of direct imaging. Significant contrast improvement is obtained compared to high-resolution electron micrographs. progress has also been made in developing time-resolved electron diffraction and imaging for the study of ultrafast dynamic processes in materials. This talk will cover these crosscutting issues and the convergence of electron and x-ray diffraction techniques toward structure determination of single molecules.

  20. Coherent exciton dynamics in the presence of underdamped vibrations

    E-Print Network [OSTI]

    Arend G. Dijkstra; Chen Wang; Jianshu Cao; Graham R. Fleming

    2014-12-22

    Recent ultrafast optical experiments show that excitons in large biological light-harvesting complexes are coupled to molecular vibration modes. These high-frequency vibrations will not only affect the optical response, but also drive the exciton transport. Here, using a model dimer system, the frequency of the underdamped vibration is shown to have a strong effect on the exciton dynamics such that quantum coherent oscillations in the system can be present even in the case of strong noise. Two mechanisms are identified to be responsible for the enhanced transport efficiency: critical damping due to the tunable effective strength of the coupling to the bath, and resonance coupling where the vibrational frequency coincides with the energy gap in the system. The interplay of these two mechanisms determines parameters responsible for the most efficient transport, and these optimal control parameters are comparable to those in realistic light-harvesting complexes. Interestingly, oscillations in the excitonic coherence at resonance are suppressed in comparison to the case of an off-resonant vibration.