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1

Linac Coherent Light Source Overview  

ScienceCinema (OSTI)

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.

None

2013-05-29T23:59:59.000Z

2

Linac Coherent Light Source Overview  

Broader source: Energy.gov [DOE]

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

3

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

4

Linac Coherent Light SourCe  

Energy Savers [EERE]

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5

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.

6

The Linac Coherent Light Source is  

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

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7

The Development of the Linac Coherent Light Source RF Gun  

E-Print Network [OSTI]

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.

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

2015-01-01T23:59:59.000Z

8

Linac Coherent Light Source Undulator RF BPM System  

SciTech Connect (OSTI)

The Linac Coherent Light Source (LCLS) will be the world's first x-ray free-electron laser (FEL) when it becomes operational in 2009. The LCLS is currently in the construction phase. The beam position monitor (BPM) system planned for the LCLS undulator will incorporate a high-resolution X-band cavity BPM system described in this paper. The BPM system will provide high-resolution measurements of the electron beam trajectory on a pulse-to-pulse basis and over many shots. The X-band cavity BPM size, simple fabrication, and high resolution make it an ideal choice for LCLS beam position detection. We will discuss the system specifications, design, and prototype test results.

Lill, R.M.; Morrison, L.H.; Waldschmidt, G.J.; Walters, D.R.; /Argonne; Johnson, R.; Li, Z.; Smith, S.; Straumann, T.; /SLAC

2007-04-17T23:59:59.000Z

9

Beam-based Feedback for the Linac Coherent Light Source  

SciTech Connect (OSTI)

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

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

2010-02-11T23:59:59.000Z

10

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

Office of Science (SC) Website

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11

High Energy Density Science at the Linac Coherent Light Source  

SciTech Connect (OSTI)

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

Lee, R W

2007-10-19T23:59:59.000Z

12

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)

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.

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

2015-01-30T23:59:59.000Z

13

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

SciTech Connect (OSTI)

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.

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)

2014-06-15T23:59:59.000Z

14

X-RAY ACTIVE MATRIX PIXEL SENSORS BASEDON J-FET TECHNOLOGY DEVELOPED FOR THE LINAC COHERENT LIGHT SOURCE.  

SciTech Connect (OSTI)

An X-ray Active Matrix Pixel Sensor (XAMPS) is being developed for recording data for the X-ray Pump Probe experiment at the Linac Coherent Light Source (LCLS). Special attention has to be paid to some technological challenges that this design presents. New processes were developed and refined to address problems encountered during previous productions of XAMPS. The development of these critical steps and corresponding tests results are reported here.

CARINI,G.A.; CHEN, W.; LI, Z.; REHAK, P.; SIDDONS, D.P.

2007-10-29T23:59:59.000Z

15

Coherent Effects of High Current Beam in Project-X Linac  

SciTech Connect (OSTI)

Resonance excitation of longitudinal high order modes in superconducting RF structures of Project-X continuous wave linac is studied. We analyze regimes of operation of the linac with high beam current, which can be used to provide an intense muon source for the future Neutrino Factory or Muon Collider, and also important for the Accelerator-Driven Subcritical systems. We calculate power loss and associated heat load to the cryogenic system. Longitudinal emittance growth is estimated. We consider an alternative design of the elliptical cavity for the high energy part of the linac, which is more suitable for high current operation.

Sukhanov, A.; Lunin, A.; Yakovlev, V.; Gonin, I.; Khabiboulline, T.; Saini, A.; Solyak, N.; Yostrikov, A.

2012-09-01T23:59:59.000Z

16

FINDING OF NO SIGNIFICANT IMPACT FOR THE LINAC COHERENT LIGHT  

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

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17

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

SciTech Connect (OSTI)

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

Not Available

2011-06-22T23:59:59.000Z

18

Variable Gap Undulator for 1.5-48 Kev Free Electron Laser at Linac Coherent Light Source  

SciTech Connect (OSTI)

We study the feasibility of generating femtosecond duration Free-Electron Laser with a variable photon energy from 1.5 to 48 keV, using an electron bunch with the same characteristics of the LINAC Coherent Light Source (LCLS) bunch, and a planar undulator with additional focusing. We assume that the electron bunch energy can be changed, and the undulator has a variable gap, allowing a variable undulator parameter. It is assumed to be operated in an ultra-low charge and ultra-short pulse regime. We study the feasibility of a tunable, short pulse, X-ray FEL with photon energy from 1.5 to 48 keV, using an electron beam like the one in the LCLS and a 2:5 cm period, variable gap, planar undulator. The beam energy changes from 4.6 to 13.8 GeV, the electorn charge is kept at 10 pC, and the undulator parameter varies from 1 to 3. The undulator length needed to saturate the 48 keV FEL is about 55 m, with a peak power around 5 GW. At longer wavelength the saturation length is as short as 15 m, and the peak power around 20 GW. The results from the analytical models and the GENESIS simulations show that the system is feasible. The large wavelength range, full tunability and short, few femtosecond pulses, together with the large peak power, would provide a powerful research tool.

Pellegrini, C.; /UCLA; Wu, J.; /SLAC; ,

2011-08-17T23:59:59.000Z

19

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

SciTech Connect (OSTI)

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

Williams, Kiel; /SLAC

2012-09-07T23:59:59.000Z

20

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)

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.

Ratner, D.; Behrens, C.; Ding, Y.; Huang, Z.; Marinelli, A.; Maxwell, T.; Zhou, F.

2015-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

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

SciTech Connect (OSTI)

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.

Stohr, J

2011-11-16T23:59:59.000Z

22

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

SciTech Connect (OSTI)

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

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

2014-11-15T23:59:59.000Z

23

Monte Carlo Studies of the Radiation Fields in the Linac Coherent Light Source Undulators and of the Corresponding Signals in the Cerenkov Beam Loss Monitors  

SciTech Connect (OSTI)

In 2009 the Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Center started free electron laser (FEL) operation. In order to continue to produce the bright and short-pulsed x-ray laser demanded by FEL scientists, this pioneer hard x-ray FEL requires a perfectly tailored magnetic field at the undulators, so that the photons generated at the electron wiggling path interact at the right phase with the electron beam. In such a precise system, small (>0.01%) radiation-induced alterations of the magnetic field in the permanent magnets could affect FEL performance. This paper describes the simulation studies of radiation fields in permanent magnets and the expected signal in the detectors. The transport of particles from the radiation sources (i.e. diagnostic insert) to the undulator magnets and to the beam loss monitors (BLM) was simulated with the intra nuclear cascade codes FLUKA and MARS15. In order to accurately reproduce the optics of LCLS, lattice capabilities and magnetic fields were enabled in FLUKA and betatron oscillations were validated against reference data. All electron events entering the BLMs were printed in data files. The paper also introduces the Radioactive Ion Beam Optimizer (RIBO) Monte Carlo 3-D code, which was used to read from the event files, to compute Cerenkov production and then to simulate the optical coupling of the BLM detectors, accounting for the transmission of light through the quartz.

Santana Leitner, Mario

2010-09-14T23:59:59.000Z

24

Welcome to Linac Coherent Light Source | Linac Coherent Light Source  

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

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25

Linac Energy Management for LCLS  

SciTech Connect (OSTI)

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).

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

2012-07-05T23:59:59.000Z

26

SLAC Linac Coherent Light Source  

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

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27

SAC - Linac Coherent Light Source  

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

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28

Safety | Linac Coherent Light Source  

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

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29

LCLS LLRF Upgrades to the SLAC Linac  

SciTech Connect (OSTI)

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

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

2007-10-04T23:59:59.000Z

30

Instability issues for the ESS linac and rings  

SciTech Connect (OSTI)

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

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

1999-12-03T23:59:59.000Z

31

CSNS LINAC DESIGN  

SciTech Connect (OSTI)

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

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

2006-08-21T23:59:59.000Z

32

Commissioning of the LCLS Linac and Bunch Compressors  

SciTech Connect (OSTI)

The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) project under construction at SLAC [1]. The injector section, from drive-laser and RF photocathode gun through the first bunch compressor, was commissioned in the spring and summer of 2007. The second phase of commissioning, including the second bunch compressor and various main linac modifications, was completed in January through August of 2008. We report here on experience gained during this second phase of machine commissioning, including the injector, the first and second bunch compressor stages, the linac up to 14 GeV, and beam stability measurements. The final commissioning phase, including the undulator and the long transport line from the linac, is set to begin in December 2008, with first light expected in July 2009.

Akre, R.; Brachmann, A.; Decker, F.-J.; Ding, Y.; Dowell, D.; Emma#, P.; Frisch, J.; Gilevich, S.; Hays, G.; Hering, Ph.; Huang, Z.; Iverson, R.; Limborg-Deprey, C.; Loos, H.; Molloy, S.; Miahnahri, A.; Nuhn, H.-D.; Ratner, D.; Turner, J.; Welch, J.; White, W.; /SLAC

2008-08-20T23:59:59.000Z

33

SLAC Linac Coherent Light Source User Site  

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

different sample preparations or potentially collect a full data set under good running conditions. To enable measurements within such a short time frame and maximize efficiency...

34

SLAC Linac Coherent Light Source User Site  

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

in the following two documents: An Engineering Specification Document (ESD). An Interface Control Document (ICD). The end station builders must be available to commit the...

35

SLAC Linac Coherent Light Source User Site  

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

| Agreements | Check-In | Computing | Safety | Shipping | Supplies & Gases | User Feedback | Publications Proposal Submission and Scheduling Step-By-Step Instructions to...

36

SLAC Linac Coherent Light Source User Site  

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

Accommodations Hours Maps Stanford Guest House This comfortable and convenient housing structure is located on SLAC's campus. Guests have access to in-room, high-speed Internet...

37

User Agreements | Linac Coherent Light Source  

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38

User Financial Accounts | Linac Coherent Light Source  

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39

User Shipments | Linac Coherent Light Source  

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40

LCLS Parameters Update | Linac Coherent Light Source  

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41

LCLS Policies | Linac Coherent Light Source  

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42

SLAC Linac Coherent Light Source User Site  

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43

SLAC Linac Coherent Light Source User Site  

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44

SLAC Linac Coherent Light Source User Site  

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45

SLAC Linac Coherent Light Source User Site  

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46

Working at SLAC | Linac Coherent Light Source  

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47

Becoming a User | Linac Coherent Light Source  

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48

Bioimaging Workshop - Linac Coherent Light Source  

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49

Collaborator Checklist | Linac Coherent Light Source  

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50

Committees & Contacts | Linac Coherent Light Source  

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51

Contact Us | Linac Coherent Light Source  

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52

Spokesperson Checklist | Linac Coherent Light Source  

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53

After Beamtime | Linac Coherent Light Source  

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54

Proposal Submission | Linac Coherent Light Source  

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55

High Brightness Beam Applications: Energy Recovered Linacs  

SciTech Connect (OSTI)

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

Geoffrey A. Krafft

2005-09-01T23:59:59.000Z

56

Compact LINAC for deuterons  

SciTech Connect (OSTI)

We are developing a compact deuteron-beam accelerator up to the deuteron energy of a few MeV based on room-temperature inter-digital H-mode (IH) accelerating structures with the transverse beam focusing using permanent-magnet quadrupoles (PMQ). Combining electromagnetic 3-D modeling with beam dynamics simulations and thermal-stress analysis, we show that IHPMQ structures provide very efficient and practical accelerators for light-ion beams of considerable currents at the beam velocities around a few percent of the speed of light. IH-structures with PMQ focusing following a short RFQ can also be beneficial in the front end of ion linacs.

Kurennoy, S S [Los Alamos National Laboratory; O' Hara, J F [Los Alamos National Laboratory; Rybarcyk, L J [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

57

Construction Status of Linac4  

E-Print Network [OSTI]

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

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

2010-01-01T23:59:59.000Z

58

Linac4 Technical Design Report  

E-Print Network [OSTI]

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

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

2006-01-01T23:59:59.000Z

59

Optimization of SRF Linacs  

SciTech Connect (OSTI)

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.

Powers, Tom [JLAB

2013-09-01T23:59:59.000Z

60

Induction Linac Pulsers  

SciTech Connect (OSTI)

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

Faltens, Andris

2011-01-07T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Source of coherent short wavelength radiation  

DOE Patents [OSTI]

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

Villa, Francesco (Alameda, CA)

1990-01-01T23:59:59.000Z

62

Drift Tube Linac Conditioning of Tank1  

E-Print Network [OSTI]

Tank1 of the Drift Tube Linac (DTL) of the Linac4 has been conditioned at the Linac4 tunnel. The tank was tuned for resonance at 352.2 MHz, and stable operation has been achieved with 725 µs long RF pulses at a repetition rate of 1 Hz. The maximum RF level that has been reached is 810 kW with a pulse width of 600 µs. Since this was the first RF structure exclusively conditioned in the Linac4 tunnel with the operation and control software of Linac4, some related issues and limitations had to be taken into account.

Shafqat, N; Toor, W A

2014-01-01T23:59:59.000Z

63

PROGRESS IN DESIGN OF THE SNS LINAC  

SciTech Connect (OSTI)

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

R. HARDEKOPF

2000-11-01T23:59:59.000Z

64

LFSC - Linac Feedback Simulation Code  

SciTech Connect (OSTI)

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.

Ivanov, Valentin; /Fermilab

2008-05-01T23:59:59.000Z

65

User Research Administration & Support | Linac Coherent Light Source  

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66

LCLS User Check-In Procedures | Linac Coherent Light Source  

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67

LCLS Users' Organization Executive Committee | Linac Coherent Light Source  

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68

Science and Instrumentation for the Linac Coherent Light Source Workshop  

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69

STANFORD SYNCHROTRON RADIATION LIGHTSOURCE LINAC COHERENT LIGHT SOURCE  

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70

LCLS Experimental Run Schedules | Linac Coherent Light Source  

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71

Before Arriving at SLAC | Linac Coherent Light Source  

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72

Benchmark of the IMPACT Code for High Intensity Beam DynamicsSimulation  

SciTech Connect (OSTI)

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

Qiang, J.; Ryne, R.D.

2006-11-16T23:59:59.000Z

73

The LINAC4 Project at CERN  

E-Print Network [OSTI]

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

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

2011-01-01T23:59:59.000Z

74

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

SciTech Connect (OSTI)

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

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

1993-05-01T23:59:59.000Z

75

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

SciTech Connect (OSTI)

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

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

2011-03-15T23:59:59.000Z

76

Status of the LINAC4 Project at CERN  

E-Print Network [OSTI]

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

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

2010-01-01T23:59:59.000Z

77

Coupled-cavity drift-tube linac  

DOE Patents [OSTI]

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

Billen, J.H.

1996-11-26T23:59:59.000Z

78

Remarks on the concept of dispersion in a curved linac  

SciTech Connect (OSTI)

A next-generation linear collider is expected to span tens of kilometers in length. For various reasons, it may be desirable to house such an accelerator in a tunnel that follows the earth's curvature rather that in a 'laser-straight' tunnel. One side effect of opting for a curved linac is the introduction of vertical dispersion. In recent years, much work has been dedicated to understand and evaluate the impact of the presence of dispersion on emittance preservation. While performing simulations with our in-house code (CHEF) we observed a discrepancy between the dispersion function it produces and that computed using other codes in use within the accelerator community. Understanding the origin and the meaning of this discrepancy required a re-examination of the meaning of the concept of dispersion in the context of a linac. The object of this note is to document our findings. We establish that the default dispersion algorithm used by CHEF corresponds to a different, and ultimately more appropriate, definition of the dispersion in presence of acceleration. Not surprisingly, a consistent definition of dispersion restores agreement between codes.

Ostiguy, Jean-Francois; /Fermilab

2009-01-01T23:59:59.000Z

79

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

Office of Environmental Management (EM)

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80

Catalytic Coherence  

E-Print Network [OSTI]

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.

Johan Aberg

2014-10-20T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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81

Retroactive Coherence  

E-Print Network [OSTI]

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

J. B. Peterson

2002-03-15T23:59:59.000Z

82

LINAC-based transuranic waste characterization system  

SciTech Connect (OSTI)

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

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

1994-12-31T23:59:59.000Z

83

Photocathodes for the energy recovery linacs  

SciTech Connect (OSTI)

This paper presents an overview of existing and emerging technologies on electron sources that can service various Energy Recovering Linacs under consideration. Photocathodes that can deliver average currents from 1 mA to 1 A, the pros and cons associated with these cathodes are addressed. Status of emerging technologies such as secondary emitters, cesiated dispenser cathodes, field and photon assisted field emitters and super lattice photocathodes are also reviewed.

T. Rao; A. Burrill; X.Y. Chang; J. Smedley; T. Nishitani; C. Hernandez Garcia; M. Poelker; E. Seddon; F.E. Hannon; C.K. Sinclair; J. Lewellen; D. Feldman

2005-03-19T23:59:59.000Z

84

PHOTOCATHODES FOR THE ENERGY RECOVERY LINACS.  

SciTech Connect (OSTI)

This paper presents an overview of existing and emerging technologies on electron sources that can service various Energy Recovering Linacs under consideration. Photocathodes that can deliver average currents from 1 mA to 1 A, the pros and cons associated with these cathodes are addressed. Status of emerging technologies such as secondary emitters, cesiated dispenser cathodes, field and photon assisted field emitters and super lattice photocathodes are also reviewed.

RAO, T.; BURRILL, A.; CHANG, X.Y.; SMEDLEY, J.; ET AL.

2005-03-19T23:59:59.000Z

85

Advanced RF power sources for linacs  

SciTech Connect (OSTI)

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

Wilson, P.B.

1996-10-01T23:59:59.000Z

86

Evaluation of photoneutron production at high energy LINACS  

SciTech Connect (OSTI)

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

Bell, Z.W.

1995-04-24T23:59:59.000Z

87

Superconducting radiofrequency linac development at Fermilab  

SciTech Connect (OSTI)

As the Fermilab Tevatron Collider program draws to a close, a strategy has emerged of an experimental program built around the high intensity frontier. The centerpiece of this program is a superconducting H- linac that will support world leading programs in long baseline neutrino experimentation and the study of rare processes. Based on technology shared with the International Linear Collider, Project X will provide multi-MW beams at 60-120 GeV from the Main Injector, simultaneous with very high intensity beams at lower energies. Project X also supports development of a Muon Collider as a future facility at the energy frontier.

Holmes, Stephen D.; /Fermilab

2009-10-01T23:59:59.000Z

88

Physics design of front ends for superconducting ion linacs  

SciTech Connect (OSTI)

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

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

2009-01-01T23:59:59.000Z

89

Physics design of front ends for superconducting ion linacs  

SciTech Connect (OSTI)

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

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

2008-09-01T23:59:59.000Z

90

RIA Superconducting Drift Tube Linac R & D  

SciTech Connect (OSTI)

Cavity and cryomodule development work for a superconducting ion linac has been underway for several years at the National Superconducting Cyclotron Laboratory. The original application of the work was the proposed Rare Isotope Accelerator. At present, the work is being continued for use with the Facility for Rare Isotope Beams (FRIB). The baseline linac for FRIB requires 4 types of superconducting cavities to cover the velocity range needed to accelerate an ion beam to #21; 200 MeV/u: 2 types of quarter-wave resonator (QWR) and 2 types of half-wave resonator (HWR). Superconducting solenoids are used for focussing. Active and passive shielding is required to ensure that the solenoids’ field does not degrade the cavity performance. First prototypes of both QWR types and one HWR type have been fabricated and tested. A prototype solenoid has been procured and tested. A test cryomodule has been fabricated and tested. The test cryomodule contains one QWR, one HWR, one solenoid, and one super-ferric quadrupole. This report covers the design, fabrication, and testing of this cryomodule

J. Popielarski; J. Bierwagen; S. Bricker; C. Compton; J. DeLauter; P. Glennon; T. Grimm; W. Hartung; D. Harvell; M. Hodek; M. Johnson; F. Marti; P. Miller; A. Moblo; D. Norton; L. Popielarski; J. Wlodarczak; R. C. York; A. Zeller

2009-05-22T23:59:59.000Z

91

WATER PURITY DEVELOPMENT FOR THE COUPLED CAVITY LINAC (CCL) AND DRIFT TUBE LINAC (DTL) STRUCTURES OF THE SPALLATION NEUTRON SOURCE (SNS) LINAC  

SciTech Connect (OSTI)

The Spallation Neutron Source (SNS) is a facility being designed for scientific and industrial research and development. SNS will generate and use neutrons as a diagnostic tool for medical purposes, material science, etc. The neutrons will be produced by bombarding a heavy metal target with a high-energy beam of protons, generated and accelerated with a linear particle accelerator, or linac. The low energy end of the linac consists of two room temperature copper structures, the drift tube linac (DTL), and the coupled cavity linac (CCL). Both of these accelerating structures use large amounts of electrical energy to accelerate the proton beam. Approximately 60-80% of the electrical energy is dissipated in the copper structure and must be removed. This is done using specifically designed water cooling passages within the linac's copper structure. Cooling water is supplied to these cooling passages by specially designed resonance control and water cooling systems. One of the primary components in the DTL and CCL water cooling systems, is a water purification system that is responsible for minimizing erosion, corrosion, scaling, biological growth, and hardware activation. The water purification system consists of filters, ion exchange resins, carbon beds, an oxygen scavenger, a UV source, and diagnostic instrumentation. This paper reviews related issues associated with water purification and describes the mechanical design of the SNS Linac water purification system.

D. KATONAK; J. BERNARDIN; S. HOPKINS

2001-06-01T23:59:59.000Z

92

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

E-Print Network [OSTI]

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

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

2008-01-01T23:59:59.000Z

93

The Linac4 DTL Prototype: Low and High Power Measurements  

E-Print Network [OSTI]

The prototype of the Linac4 Drift Tube Linac (DTL) has undergone low power measurements in order to verify the RF coupling and to adjust the post-coupler lengths based on bead-pull and spectrum measurements. Following the installation at the test stand, the cavity has been subjected to high power operation at Linac4 and SPL duty cycles. Saturation effects and multipacting have been observed and linked to X-ray emission. Voltage holding is reported in the presence of magnetic fields from permanent magnet quadrupoles (PMQ) installed in the first drift tubes.

De Michele, G; Marques-Balula, J; Ramberger, S

2012-01-01T23:59:59.000Z

94

Energy Recovery Linacs for Light Source Applications  

SciTech Connect (OSTI)

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

George Neil

2011-04-01T23:59:59.000Z

95

A Program for Optimizing SRF Linac Costs  

SciTech Connect (OSTI)

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

Powers, Thomas J. [JLAB

2013-04-01T23:59:59.000Z

96

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

SciTech Connect (OSTI)

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

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

2003-12-16T23:59:59.000Z

97

End to End Beam Dynamics of the ESS Linac  

E-Print Network [OSTI]

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

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

2012-01-01T23:59:59.000Z

98

LINAC4, A New $H^{-}$ Linear Injector at CERN  

E-Print Network [OSTI]

Linac2, the present injector of the CERN PS Booster, limits the performance of the proton accelerator complex because of its low output energy (50 MeV). To remove this bottleneck, a higher energy linac is proposed (called â??Linac4â? ) which will double the brightness and the intensity of the beam delivered by the PSB and ensure the â??ultimateâ? beam is available for LHC. Linac4 will deliver H- ions at a kinetic energy of 160 MeV. It is designed to be usable as the front-end of a future multi-GeV multi-MW linear accelerator, the â??Superconducting Proton Linacâ? (SPL). R&D for Linac4 is now actively taking place with the support of the European Union through the Joint Research Activity HIPPI (â??High Intensity Pulsed Proton Injectorsâ?), and of three ISTC projects involving three major Russian laboratories (BINP, IHEP and ITEP) and two nuclear centres (VNIIEF and VNIITF). The design of this new accelerator and the on-going developments are described.

Garoby, R; Hanke, K; Lombardi, A M; Rossi, C; Vretenar, M

2004-01-01T23:59:59.000Z

99

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

E-Print Network [OSTI]

1Mechanical, Aerospace and Nuclear Engineering nacThe Gaerttner Laboratory RPI LINAC Facility and Nuclear Engineering nacThe Gaerttner Laboratory Capabilities of the RPI LINAC · Pulsed Electron Beam ­ 7ns;4Mechanical, Aerospace and Nuclear Engineering nacThe Gaerttner Laboratory Capabilities of the RPI LINAC

Danon, Yaron

100

Maximal Privacy without Coherence  

E-Print Network [OSTI]

Privacy is a fundamental feature of quantum mechanics. A coherently transmitted quantum state is inherently private. Remarkably, coherent quantum communication is not a prerequisite for privacy: there are quantum channels ...

Leung, Debbie

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

BEAM SIMULATIONS USING VIRTUAL DIAGNOSTICS FOR THE DRIVER LINAC  

SciTech Connect (OSTI)

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

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

2011-12-21T23:59:59.000Z

102

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

SciTech Connect (OSTI)

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.

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

2014-05-15T23:59:59.000Z

103

Generation of Coherent X-Ray Radiation Through Modulation Compression  

E-Print Network [OSTI]

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

Qiang, Ji

2010-01-01T23:59:59.000Z

104

Generation of Coherent X-Ray Radiation Through Modulation Compression  

SciTech Connect (OSTI)

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

Qiang, Ji; Wu, Juhao

2010-12-14T23:59:59.000Z

105

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

SciTech Connect (OSTI)

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

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

2011-02-07T23:59:59.000Z

106

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

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

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

107

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

Office of Science (SC) Website

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

108

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

E-Print Network [OSTI]

LT-C-ESH-LCSAD-001, Ver. 2 Linac Commissioning Safety Assessment Document for the National Synchrotron Light Source II ii LT-C-ESH-LCSAD-001 ii DISCLAIMER This report was prepared as an account of work, or subcontractor thereof. #12;LT-C-ESH-LCSAD-001, Ver. 2 Photon Sciences Directorate National Synchrotron Light

Ohta, Shigemi

109

Generalized coherent states  

E-Print Network [OSTI]

In the coherent state of the harmonic oscillator, the probability density is that of the ground state subjected to an oscillation along a classical trajectory. Senitzky and others pointed out that there are states of the harmonic oscillator corresponding to an identical oscillatory displacement of the probability density of any energy eigenstate. These generalizations of the coherent state are rarely discussed, yet they furnish an interesting set of quantum states of light that combine features of number states and coherent states. Here we give an elementary account of the quantum optics of generalized coherent states.

T. G. Philbin

2013-12-18T23:59:59.000Z

110

Single-cycle Terahertz Pulses with >0.2 V/A Field Amplitudes via Coherent Transition Radiation  

SciTech Connect (OSTI)

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

Daranciang, Dan; /Stanford U., Chem. Dept.; Goodfellow, John; /Stanford U. Materials Sci. Dept.; Fuchs, Matthias; /SIMES, Stanford /SLAC, PULSE; Wen, Haidan; /ANL, APS; Ghimire, Shambhu; /SLAC, PULSE; Reis, David A.; /SIMES, Sanford /SLAC, PULSE /Stanford U., Appl. Phys. Dept.; Loos, Henrik; Fisher, Alan S.; /SLAC, LCLS; Lindenberg, Aaron M.; /Stanford U. Materials Sci. Dept. /SIMES, Stanford /SLAC, PULSE

2012-02-15T23:59:59.000Z

111

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

SciTech Connect (OSTI)

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

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

2011-10-03T23:59:59.000Z

112

Linac-Based Proton Driver for a Neutrino Factory  

E-Print Network [OSTI]

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

Garoby, R; Aiba, M; Meddahi, M

2009-01-01T23:59:59.000Z

113

Linac4 Low Energy Beam Measurements with Negative Hydrogen  

E-Print Network [OSTI]

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

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

2013-01-01T23:59:59.000Z

114

HIGH DYNAMIC-RANGE HIGH SPEED LINAC CURRENT MEASUREMENTS  

SciTech Connect (OSTI)

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

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

2012-01-01T23:59:59.000Z

115

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

SciTech Connect (OSTI)

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.

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

2008-12-01T23:59:59.000Z

116

E-Print Network 3.0 - argonne tandem-linac accelerator Sample...  

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

Page: << < 1 2 3 4 5 > >> 1 Key facts about Argonne National Laboratory Summary: Facility Argonne Tandem Linac Accelerator System Atmospheric Radiation Measurement Climate...

117

E-Print Network 3.0 - alverez linac structures Sample Search...  

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

... Source: Utah, University of - State of Utah Center of Excellence for Biomedical Microfluidics Collection: Engineering 2 The CCDTL for Linac4: The ISTC Support to LHC Luminosity...

118

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...

119

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...

120

Ultrafast X-Ray Coherent Control  

SciTech Connect (OSTI)

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.

Reis, David

2009-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Compensating effect of the coherent synchrotron radiation in bunch compressors  

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

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

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

2013-06-01T23:59:59.000Z

122

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

E-Print Network [OSTI]

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

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

1998-01-01T23:59:59.000Z

123

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

E-Print Network [OSTI]

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

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

2002-01-01T23:59:59.000Z

124

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

E-Print Network [OSTI]

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

Suwada, T

2001-01-01T23:59:59.000Z

125

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

E-Print Network [OSTI]

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

126

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

E-Print Network [OSTI]

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

127

PERFORMANCE OF THE TESLA TEST FACILITY LINAC for the TESLA Collaboration  

E-Print Network [OSTI]

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

128

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

E-Print Network [OSTI]

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

129

Large dynamic range diagnostics for high current electron LINACs  

SciTech Connect (OSTI)

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.

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

2013-11-07T23:59:59.000Z

130

OPERATIONAL ASPECTS OF HIGH POWER ENERGY RECOVERY LINACS  

SciTech Connect (OSTI)

We have been operating a high-power energy-recovery linac (ERL) at Jefferson Lab for several years. In the process we have learned quite a bit about both technical and physics limitations in high power ERLs. Several groups are now considering new ERLs that greatly increase either the energy, the current or both. We will present some of our findings on what to consider when designing, building, and operating a high power ERL. Our remarks for this paper are limited to lattice design and setup, magnets, vacuum chamber design, diagnostics, and beam stability.

Stephen Benson; David Douglas; Pavel Evtushenko; Kevin Jordan; George Neil; Paul Powers

2006-08-21T23:59:59.000Z

131

SAR image effects on coherence and coherence estimation.  

SciTech Connect (OSTI)

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.

Bickel, Douglas Lloyd

2014-01-01T23:59:59.000Z

132

Linac4 45 keV Proton Beam Measurements  

E-Print Network [OSTI]

Linac4 is a 160 MeV normal-conducting H- linear accelerator, which will replace the 50 MeV proton Linac2 as injector for the CERN proton complex. Commissioning of the low energy part - comprising the H - source, a 45 keV Low Energy Beam Transport line (LEBT), a 3 MeV Radiofrequency Quadrupole (RFQ) and a Medium Energy Beam Transport (MEBT) - will start in fall 2012 on a dedicated test stand installation. In preparation to this, preliminary measurements were taken using a 45 keV proton source and a temporary LEBT setup, with the aim of characterising the output beam by comparison with the predictions of simulations. At the same time this allowed a first verification of the functionalities of diagnostics instrumentation and acquisition software tools. Measurements of beam profile, emittance and intensity were taken in three different setups: right after the source, after the first and after the second LEBT solenoids respectively. Particle distributions were reconstructed from emittance scan...

Bellodi, G; Hein, L M; Lallement, J-B; Lombardi, A M; Midttun, O; Scrivens, R; Posocco, P A

2013-01-01T23:59:59.000Z

133

Linac cryogenic distribution system maintenance and upgrades at JLab  

SciTech Connect (OSTI)

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

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

2014-01-29T23:59:59.000Z

134

Linac cryogenic distribution system maintenance and upgrades at Jlab  

SciTech Connect (OSTI)

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

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

2014-01-01T23:59:59.000Z

135

Superconducting RF Linac Technology for ERL Light Sources  

SciTech Connect (OSTI)

Energy Recovering Linacs (ERLs) offer an attractive alternative as drivers for light sources as they combine the desirable characteristics of both storage rings (high efficiency) and linear accelerators (superior beam quality). Using superconducting RF technology allows ERLs to operate more efficiently because of the inherent characteristics of SRF linacs, namely that they are high gradient-low impedance structures and their ability to operate in the long pulse or CW regime. We present an overview of the physics challenges encountered in the design and operation of ERL based light sources with particular emphasis on those issues related to SRF technology. These challenges include maximizing a cavity�������¢����������������s Qo to increase cryogenic efficiency, maintaining control of the cavity field in the presence of the highest feasible loaded Q and providing adequate damping of the higher-order modes (HOMs). If not sufficiently damped, dipole HOMs can drive the multipass beam breakup (BBU) instability which ERLs are particularly susceptible to. Another challenge involves efficiently extracting the potentially large amounts of HOM power that are generated when a bunch traverses the SRF cavities and which may extend over a high range of frequencies. We present experimental data from the Jefferson Lab FEL Upgrade, a 10 mA ERL light source presently in operation, aimed at addressing some of these issues. We conclude with an outlook towards the future of ERL based light sources.

Chris Tennant

2005-08-01T23:59:59.000Z

136

Bidirectional coherent classical communication  

E-Print Network [OSTI]

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

Aram W. Harrow; Debbie W. Leung

2005-05-12T23:59:59.000Z

137

Coherent soliton communication lines  

SciTech Connect (OSTI)

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.

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

2014-11-15T23:59:59.000Z

138

Coherent Radiation in an Undulator  

E-Print Network [OSTI]

solving the particle-radiation system in a self-consistentto clarify the coherent radiation mechanism. References 1.the Proceedings Coherent Radiation in an Undulator Y,H. Chin

Chin, Y.H.

2011-01-01T23:59:59.000Z

139

Intense terahertz pulses from SLAC electron beams using coherent transition radiation  

SciTech Connect (OSTI)

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

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

2013-02-15T23:59:59.000Z

140

PULSED-FOCUSING RECIRCULATING LINACS FOR MUON ACCELERATION  

SciTech Connect (OSTI)

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.

Johnson, Rolland PAUL

2014-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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141

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

SciTech Connect (OSTI)

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.

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

2007-06-25T23:59:59.000Z

142

Quantum Coherence Engines  

E-Print Network [OSTI]

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.

Elias P. Gyftopoulos

2007-06-20T23:59:59.000Z

143

Coherent hybrid electromagnetic field imaging  

DOE Patents [OSTI]

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.

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

2008-08-26T23:59:59.000Z

144

Design study of a medical proton linac for neutron therapy  

SciTech Connect (OSTI)

This paper describes a design study which establishes the physical parameters of the low energy beam transport, radiofrequency quadrupole, and linac, using computer programs available at Fermilab. Beam dynamics studies verify that the desired beam parameters can be achieved. The machine described here meets the aforementioned requirements and can be built using existing technology. Also discussed are other technically feasible options which could be attractive to clinicians, though they would complicate the design of the machine and increase construction costs. One of these options would allow the machine to deliver 2.3 MeV protons to produce epithermal neutrons for treating brain tumors. A second option would provide 15 MeV protons for isotope production. 21 refs., 33 figs.

Machida, S.; Raparia, D.

1988-08-26T23:59:59.000Z

145

THE SNS VACUUM CONTROL SYSTEM UPGRADE FOR THE SUPERCONDUCTING LINAC  

SciTech Connect (OSTI)

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.

Williams, Derrick C [ORNL] [ORNL

2009-01-01T23:59:59.000Z

146

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

SciTech Connect (OSTI)

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

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

2008-09-01T23:59:59.000Z

147

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

SciTech Connect (OSTI)

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

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

2005-01-01T23:59:59.000Z

148

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

E-Print Network [OSTI]

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

Zholents, Alexander A

2008-01-01T23:59:59.000Z

149

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

E-Print Network [OSTI]

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

Boyer, Edmond

150

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

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

151

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

E-Print Network [OSTI]

HIGH INTENSITY LINAC DRIVER FOR THE SPIRAL-2 PROJECT : DESIGN OF SUPERCONDUCTING 88 MHZ QUARTER to the required energy. · Capability to accelerate ion beams of q/A=1/6 (up to 1 mA) in the future. The initial Abstract A superconducting linac driver, delivering deuterons with an energy up to 40 MeV (5 mA) and heavy

Paris-Sud XI, Université de

152

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

SciTech Connect (OSTI)

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

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

1982-04-01T23:59:59.000Z

153

Free electron laser amplifier driven by an induction linac  

SciTech Connect (OSTI)

This paper discusses the use of a free-electron laser amplifier as a means of converting the kinetic energy of an electron beam into coherent radiation. In particular, the use of an induction linear accelerator is discussed. The motion of the elections in the tapered and untapered wiggler magnets is discussed as well as the beam emittance, and the radiation fields involved. (LSP)

Neil, V.K.

1986-06-03T23:59:59.000Z

154

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

SciTech Connect (OSTI)

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.

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

2013-01-01T23:59:59.000Z

155

Preliminary Analysis on Linac Oscillation Data LI05-19 and Wake Field Energy Loss in FACET Commissioning 2012  

SciTech Connect (OSTI)

In this note, preliminary analysis on linac ocsillation data in FACET linac LI05-09 plus LI11-19 is presented. Several quadrupoles are identified to possibly have different strength, compared with their designed strength in the MAD optics model. The beam energy loss due to longitudinal wake fields in the S-band linac is also analytically calculated, also by LITRACK numerical simulations.

Sun, Yipeng; /SLAC

2012-07-23T23:59:59.000Z

156

Coherent states on the circle  

E-Print Network [OSTI]

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

Chadzitaskos, G; Tolar, J

2011-01-01T23:59:59.000Z

157

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

SciTech Connect (OSTI)

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

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

2007-01-01T23:59:59.000Z

158

Coherent Synchrotron Radiation Analysis  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New SubstationClean Communities ofCellulosic Feedstock - EnergyCoal2NuclearCoherent

159

Status of the plasma generator of the superconducting proton linac  

SciTech Connect (OSTI)

In the framework of the superconducting proton linac (SPL) study at CERN, a new non-cesiated H{sup -} plasma generator driven by an external 2 MHz RF antenna has been developed and successfully operated at repetition rates of 50 Hz, pulse lengths of up to 3 ms, and average RF powers of up to 3 kW. The coupling efficiency of RF power into the plasma was determined by the cooling water temperatures and the analysis of the RF forward and reflected power and the antenna current and amounts to 50%-60%. The plasma resistance increases between 10 kW and 40 kW RF power from about 0.45 {Omega} to 0.65 {Omega}. Measurements of RF power dissipated in the ferrites and the magnets on a test bench show a 5-fold decrease of the power losses for the magnets when they are contained in a Cu box, thus validating the strategy of shielding the magnets with a high electrical conductivity material. An air cooling system was installed in the SPL plasma generator to control the temperatures of the ferrites despite hysteresis losses of several Watts.

Kronberger, M.; Lettry, J.; Paoluzzi, M.; Pereira, H.; Arias, J. Sanchez; Schmitzer, C.; Scrivens, R. [European Organisation for Nuclear Research, CERN, 1211 Geneva 23 (Switzerland); Faircloth, D. [STFC, Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX (United Kingdom)

2012-02-15T23:59:59.000Z

160

Field stability in two-stem drift-tube linacs  

SciTech Connect (OSTI)

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

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

1988-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Higher Order Mode Heating Analysis for the ILC Superconducting Linacs  

SciTech Connect (OSTI)

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

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

2010-10-27T23:59:59.000Z

162

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

SciTech Connect (OSTI)

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

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

2014-06-09T23:59:59.000Z

163

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

E-Print Network [OSTI]

extraordinarily tiny that visible light waves pass right by them without being reflected. X-rays, on the other. Harnessing the Ultra-fast The atomic and molecular world is abuzz with frenetic motion. Mol- ecules understanding of photosyn- thesis--a highly efficient use of the sun's energy--has implications for future

Wechsler, Risa H.

164

MODEL AND BEAM BASED SETUP PROCEDURES FOR A HIGH POWER HADRON SUPERCONDUCTING LINAC  

SciTech Connect (OSTI)

This presentation will review methods for experimental determination of optimal operational set points in a multi-cavity superconducting high power hadron linac. A typical tuning process is based on comparison between measured data and the results of simulations from envelope and single-particle models. Presence of significant space charge effects requires simulation and measurement of bunch dynamics in 3 dimensions to ensure low loss beam transport. This is especially difficult in a superconducting linac where use of interceptive diagnostics is usually restricted because of the risk of SRF cavity surface contamination. The procedures discussed here are based on non-interceptive diagnostics such as beam position monitors and laser wires, and conventional diagnostics devices such as wire scanners and bunch shape monitors installed outside the superconducting linac. The longitudinal Twiss analysis based on the BPM signals will be described. The superconducting SNS linac tuning experience will be used to demonstrate problems and their solution for real world linac tune-up procedures

Shishlo, Andrei P [ORNL

2014-01-01T23:59:59.000Z

165

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

SciTech Connect (OSTI)

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

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

2014-01-29T23:59:59.000Z

166

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

E-Print Network [OSTI]

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

Shen, Qun

167

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

SciTech Connect (OSTI)

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.

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

2012-07-01T23:59:59.000Z

168

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

E-Print Network [OSTI]

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

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

2014-01-01T23:59:59.000Z

169

Design, Manufacture and Measurements of Permanent Quadrupole Magnets for Linac4  

E-Print Network [OSTI]

Compact quadrupole magnets are required for the CCDTL (Cell-Coupled Drift Tube Linac) of Linac 4, a 160 MeV linear accelerator of negative hydrogen ions which will replace the old 50 MeV proton Linac2 at CERN. The magnets, of an overall physical length of 140 mm and an aperture diameter of 45 mm, are based on Sm2Co17 blocks and can provide an integrated gradient of up to 1.6 Tesla. The magnetic field quality is determined by 4 ferromagnetic pole tips, aligned together with the permanent magnets blocks inside a structure made in a single piece. Tuning bars allow to individually trim the magnetic flux provided by each pole, to correct possible differences between blocks and to modify the field gradient intensity within about 20% of the nominal value. The paper describes and discusses the design, manufacture and magnetic measurements of a first prototype magnet.

Tommasini, D; Thonet, P; Vorozhtsov, A

2012-01-01T23:59:59.000Z

170

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

E-Print Network [OSTI]

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

Tan, J; Søby, L; Sordet, M; Wendt, M

2013-01-01T23:59:59.000Z

171

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

SciTech Connect (OSTI)

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

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

2001-06-18T23:59:59.000Z

172

INCREASED UNDERSTANDING OF BEAM LOSSES FROM THE SNS LINAC PROTON EXPERIMENT  

SciTech Connect (OSTI)

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

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

2013-01-01T23:59:59.000Z

173

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

E-Print Network [OSTI]

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

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

2013-01-01T23:59:59.000Z

174

Coherent control of neutron interferometry  

E-Print Network [OSTI]

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. ...

Pushin, Dmitry A

2007-01-01T23:59:59.000Z

175

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

SciTech Connect (OSTI)

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

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

2012-06-20T23:59:59.000Z

176

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

SciTech Connect (OSTI)

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.

Ben-Zvi, Ilan

2013-03-31T23:59:59.000Z

177

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

E-Print Network [OSTI]

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

178

DESIGN FOR A 1.3 MW, 13 MEV BEAM DUMP FOR AN ENERGY RECOVERY LINAC*  

E-Print Network [OSTI]

an Energy Recovery Linac (ERL) is dumped at an energy close to the injection energy. This energy is chosen a 100 mA average current ERL as a synchrotron radiation source. The 13 MeV optimum injection energy resulting from the abrupt thermal cycles associated with beam trips is a potential failure mechanism. We

179

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

E-Print Network [OSTI]

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

Danon, Yaron

180

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

SciTech Connect (OSTI)

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

Wangler, Thomas P.,

2002-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Quantum coherence and correlations in quantum system  

E-Print Network [OSTI]

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

Zhengjun Xi; Yongming Li; Heng Fan

2014-12-24T23:59:59.000Z

182

Novel linac structures for low-beta ions and for muons  

SciTech Connect (OSTI)

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

Kurennoy, Sergey S [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

183

Atmospheric rivers as Lagrangian coherent structures  

E-Print Network [OSTI]

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.

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

2015-01-01T23:59:59.000Z

184

Practical Witness for Electronic Coherences  

E-Print Network [OSTI]

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

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

2014-08-13T23:59:59.000Z

185

Coherent scattering from a free gas  

E-Print Network [OSTI]

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 ...

Sanders, Scott N.

186

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

SciTech Connect (OSTI)

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

Prosnitz, D.

1987-01-11T23:59:59.000Z

187

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

SciTech Connect (OSTI)

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

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

2014-02-15T23:59:59.000Z

188

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

E-Print Network [OSTI]

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

Shi-Lun, Pei; Ou-Zheng, Xiao

2011-01-01T23:59:59.000Z

189

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

SciTech Connect (OSTI)

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

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

2011-03-28T23:59:59.000Z

190

A versatile, high-power proton linac for accelerator driven transmutation technologies  

SciTech Connect (OSTI)

We are applying the new coupled-cavity drift-tube linac (CCDTL) to a conceptual design of a high-current, CW accelerator for transmutation applications. A 350-MHz RFQ followed by 700--MHz structures accelerates a 100-mA proton beam to I GeV. Several advantages stem from four key features: (1) a uniform focusing lattice from the start of the CCDTL at about 7 MeV to the end of the linac, (2) external location and separate mechanical support of the electromagnetic quadrupole magnets, (3) very flexible modular physics design and mechanical implementation, and (4) compact, high-frequency structures. These features help to reduce beam loss and, hence, also reduce potential radioactivation of the structure. They result in easy alignment, fast serviceability, and high beam availability. Beam funneling, if necessary, is possible at any energy after the RFQ.

Billen, J.H.; Nath, S.; Stovall, J.E.; Takeda, H.; Wood, R.L.; Young, L.M.

1995-05-01T23:59:59.000Z

191

Chapter 4: Phenomenological Coherence Introduction  

E-Print Network [OSTI]

38 Chapter 4: Phenomenological Coherence Introduction The central thesis of this dissertation. In this chapter, I will highlight particular phenomenological aspects of this and other analogies. In following chapter, I will address the implications that these phenomenological properties have on cognitive

Maryland at College Park, University of

192

Constructing matrices with optimal block coherence  

E-Print Network [OSTI]

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

Thompson, Andrew

193

Quantizations on the circle and coherent states  

E-Print Network [OSTI]

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

Chadzitaskos, G; Tolar, J

2012-01-01T23:59:59.000Z

194

Coherent Phase Argument for Inflation  

E-Print Network [OSTI]

Cosmologists have developed a phenomenally successful picture of structure in the universe based on the idea that the universe expanded exponentially in its earliest moments. There are three pieces of evidence for this exponential expansion -- {\\it inflation} -- from observations of anisotropies in the cosmic microwave background. First, the shape of the primordial spectrum is very similar to that predicted by generic inflation models. Second, the angular scale at which the first acoustic peak appears is consistent with the flat universe predicted by inflation. Here I describe the third piece of evidence, perhaps the most convincing of all: the phase coherence needed to account for the clear peak/trough structure observed by the WMAP satellite and its predecessors. I also discuss alternatives to inflation that have been proposed recently and explain how they produce coherent phases.

Scott Dodelson

2003-09-05T23:59:59.000Z

195

Measuring linac photon beam energy through EPID image analysis of physically wedged fields  

SciTech Connect (OSTI)

Purpose: Electronic portal imaging devices (EPIDs) have proven to be useful tools for measuring several parameters of interest in linac quality assurance (QA). However, a method for measuring linac photon beam energy using EPIDs has not previously been reported. In this report, such a method is devised and tested, based on fitting a second order polynomial to the profiles of physically wedged beams, where the metric of interest is the second order coefficient?. The relationship between ? and the beam quality index [percentage depth dose at 10 cm depth (PDD{sub 10})] is examined to produce a suitable calibration curve between these two parameters. Methods: Measurements were taken in a water-tank for beams with a range of energies representative of the local QA tolerances about the nominal value 6 MV. In each case, the beam quality was found in terms of PDD{sub 10} for 100 × 100 mm{sup 2} square fields. EPID images of 200 × 200 mm{sup 2} wedged fields were then taken for each beam and the wedge profile was fitted in MATLAB 2010b (The MathWorks, Inc., Natick, MA). ? was then plotted against PDD{sub 10} and fitted with a linear relation to produce the calibration curve. The uncertainty in ? was evaluated by taking five repeat EPID images of the wedged field for a beam of 6 MV nominal energy. The consistency of measuring ? was found by taking repeat measurements on a single linac over a three month period. The method was also tested at 10 MV by repeating the water-tank crosscalibration for a range of energies centered approximately about a 10 MV nominal value. Finally, the calibration curve from the test linac and that from a separate clinical machine were compared to test consistency of the method across machines in a matched fleet. Results: The relationship between? and PDD{sub 10} was found to be strongly linear (R{sup 2} = 0.979) while the uncertainty in ? was found to be negligible compared to that associated with measuring PDD{sub 10} in the water-tank (±0.3%). The repeat measurements over a three month period showed the method to be reasonably consistent (i.e., well within the limits defined by local QA tolerances). The measurements were repeated on a matched machine and the same linear relationship between ? and PDD{sub 10} was observed. The results for both machines were found to be indistinguishable across the energy range of interest (i.e., across and close to the thresholds defined by local QA tolerances), hence a single relation could be established across a matched fleet. Finally, the experiment was repeated on both linacs at 10 MV, where the linear relationship between ? and PDD{sub 10} was again observed. Conclusions: The authors conclude that EPID image analysis of physically wedged beam profiles can be used to measure linac photon beam energy. The uncertainty in such a measurement is dominated by that associated with measuring PDD{sub 10} in the water-tank; hence, the accuracies of these two methods are directly comparable. This method provides a useful technique for quickly performing energy constancy measurements while saving significant clinical downtime for QA.

Dawoud, S. M., E-mail: samir.dawoud@leedsth.nhs.uk; Weston, S. J.; Bond, I.; Ward, G. C.; Rixham, P. A.; Mason, J.; Huckle, A. [Department of Medical Physics and Engineering, St. James Institute of Oncology, St. James University Hospital, Leeds LS9 7TF (United Kingdom)] [Department of Medical Physics and Engineering, St. James Institute of Oncology, St. James University Hospital, Leeds LS9 7TF (United Kingdom); Sykes, J. R. [Institute of Medical Physics, School of Physics, The University of Sydney, New South Wales 2006, Australia and Department of Medical Physics and Engineering, St. James Institute of Oncology, St. James University Hospital, Leeds LS9 7TF (United Kingdom)] [Institute of Medical Physics, School of Physics, The University of Sydney, New South Wales 2006, Australia and Department of Medical Physics and Engineering, St. James Institute of Oncology, St. James University Hospital, Leeds LS9 7TF (United Kingdom)

2014-02-15T23:59:59.000Z

196

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]

to the LINAG driver. End-to-end simulations (low-energy beam lines, RFQ, medium-energy beam line, SC linac is proposed for the production of the radioactive ions, with the aim of at least 1013 fissions per second) and a superconducting linac with independent resonators (QWRs and/or HWRs). The accelerating optimisation has

Boyer, Edmond

197

Does coherence enhance transport in photosynthesis?  

E-Print Network [OSTI]

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

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

2012-10-18T23:59:59.000Z

198

Does coherence enhance transport in photosynthesis?  

E-Print Network [OSTI]

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

Kassal, Ivan; Rahimi-Keshari, Saleh

2012-01-01T23:59:59.000Z

199

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

SciTech Connect (OSTI)

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

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

2013-07-01T23:59:59.000Z

200

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

SciTech Connect (OSTI)

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

Crisp, J.

1990-10-25T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

A 4 to 0.1 nm FEL Based on the SLAC Linac  

SciTech Connect (OSTI)

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.

Pellegrini, C.; /UCLA

2012-06-05T23:59:59.000Z

202

Decoherence of multimode thermal squeezed coherent states  

SciTech Connect (OSTI)

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

Yeh, L.

1992-08-14T23:59:59.000Z

203

Coherence delay augmented laser beam homogenizer  

DOE Patents [OSTI]

The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.

Rasmussen, P.; Bernhardt, A.

1993-06-29T23:59:59.000Z

204

Coherence delay augmented laser beam homogenizer  

DOE Patents [OSTI]

The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.

Rasmussen, Paul (Livermore, CA); Bernhardt, Anthony (Berkeley, CA)

1993-01-01T23:59:59.000Z

205

Coherent states for the nonlinear harmonic oscillator  

SciTech Connect (OSTI)

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

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

2012-06-15T23:59:59.000Z

206

Optimization Online - On the Coherent Risk Measure ...  

E-Print Network [OSTI]

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

KEREM UGURLU

2014-11-25T23:59:59.000Z

207

Coherent Control of Quantum Matter  

SciTech Connect (OSTI)

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

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

2011-10-05T23:59:59.000Z

208

Coherent instabilities in random lasers  

SciTech Connect (OSTI)

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

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

2011-08-15T23:59:59.000Z

209

Pulsed spallation neutron source with an induction linac and a fixed-field alternating-gradient accelerator  

SciTech Connect (OSTI)

The paper describes an accelerator scenario of a Pulsed Spallation Neutron Source made of an Induction Linac injecting into a Fixed-Field Alternating-Gradient Accelerator (FFAG). The motivations underlying the proposal deal with the concern of removing technical risks peculiar to other scenarios involving RF Linacs, Synchrotrons and Accumulator Rings, which originate, for example, from the need of developing intense negative-ion sources and of multi-turn injection into the Compressor Rings. The system proposed here makes use of a positive-ion source of very short pulse duration, and of single-turn transfer into the circular accelerator.

Ruggiero, A.G. [Brookhaven National Lab., Upton, NY (United States); Bauer, G. [Paul Scherrer Institute, Villigen (Switzerland); Faltens, A. [Lawrence Berkeley National Lab., CA (United States)] [and others

1995-12-01T23:59:59.000Z

210

DEVELOPMENT OF A PRECISION TUNABLE GAMMA-RAY SOURCE DRIVEN BY A COMPACT X-BAND LINAC  

SciTech Connect (OSTI)

A precision, tunable gamma-ray source driven by a compact, high-gradient X-band linac is currently under development at LLNL. High-brightness, relativistic electron bunches produced by the linac interact with a Joule-class, 10 ps laser pulse to generate tunable {gamma}-rays in the 0.5-2.5 MeV photon energy range via Compton scattering. The source will be used to excite nuclear resonance fluorescence lines in various isotopes; applications include homeland security, stockpile science and surveillance, nuclear fuel assay, and waste imaging and assay. The source design, key parameters, and current status are presented.

Hartemann, F V; Albert, F; Anderson, G G; Anderson, S G; Bayramian, A J; Betts, S M; Chu, T S; Cross, R R; Ebbers, C A; Fisher, S E; Gibson, D J; Ladran, A S; Messerly, M J; Semenov, V A; Shverdin, M Y; Siders, C W; McNabb, D P; Barty, C J; Vlieks, A E; Jongewaard, E N; Tantawi, S G

2009-04-30T23:59:59.000Z

211

Optical coherence domain reflectometry guidewire  

DOE Patents [OSTI]

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.

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

2001-01-01T23:59:59.000Z

212

Compact X-ray Source using a High Repetition Rate Laser and Copper Linac  

E-Print Network [OSTI]

A design for a compact x-ray light source (CXLS) with flux and brilliance orders of magnitude beyond existing laboratory scale sources is presented. The source is based on inverse Compton scattering of a high brightness electron bunch on a picosecond laser pulse. The accelerator is a novel high-efficiency standing-wave linac and RF photoinjector powered by a single ultrastable RF transmitter at x-band RF frequency. The high efficiency permits operation at repetition rates up to 1 kHz, which is further boosted to 100 kHz by operating with trains of 100 bunches of 100 pC charge, each separated by 5 ns. The 100 kHz repetition rate is orders of magnitude beyond existing high brightness copper linacs. The entire accelerator is approximately 1 meter long and produces hard x-rays tunable over a wide range of photon energies. The colliding laser is a Yb:YAG solid-state amplifier producing 1030 nm, 100 mJ pulses at the same 1 kHz repetition rate as the accelerator. The laser pulse is frequency-doubled and stored for m...

Graves, W S; Brown, P; Carbajo, S; Dolgashev, V; Hong, K -H; Ihloff, E; Khaykovich, B; Lin, H; Murari, K; Nanni, E A; Resta, G; Tantawi, S; Zapata, L E; Kärtner, F X; Moncton, D E

2014-01-01T23:59:59.000Z

213

Coherence in natural language : data structures and applications  

E-Print Network [OSTI]

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

Wolf, Florian, 1975-

2005-01-01T23:59:59.000Z

214

Can Natural Sunlight Induce Coherent Exciton Dynamics?  

E-Print Network [OSTI]

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

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

2014-08-21T23:59:59.000Z

215

The Fidelity and Trace Norm Distances for Quantifying Coherence  

E-Print Network [OSTI]

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

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

2014-10-30T23:59:59.000Z

216

Coherent Quantum Dynamics: What Fluctuations Can Tell  

E-Print Network [OSTI]

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

Schliemann, John

2015-01-01T23:59:59.000Z

217

aligning coherent bremsstrahlung: Topics by E-print Network  

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

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

218

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...

219

Quantum Coherence Arguments for Cosmological Scale  

SciTech Connect (OSTI)

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

Lindesay, James; /SLAC

2005-05-27T23:59:59.000Z

220

Lorentz Coherence and the Proton Form Factor  

E-Print Network [OSTI]

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.

Kim, Young S

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

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

E-Print Network [OSTI]

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

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

2013-01-01T23:59:59.000Z

222

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

SciTech Connect (OSTI)

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.

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

2012-04-15T23:59:59.000Z

223

The stripping foil test stand in the Linac4 transfer line  

E-Print Network [OSTI]

The 160 MeV H? beam from the Linac4 (L4) linear accelerator at CERN will be injected into the proton synchrotron booster (PSB) with a new H? charge-exchange injection system. It will include a stripping foil, to convert H? into protons by stripping off the electrons. To gain experience with these very fragile foils, prior to the installation in the PSB, and test different foil materials and thicknesses, lifetimes of the foils, the foil changing mechanism and interlocking functions, a stripping foil test stand will be installed in the L4 transfer line in 2015. This paper describes the mechanical design of the system and discusses the test possibilities and parameters.

Weterings, W; Noulibos, R; Sillanoli, Y; van Trappen, P

2015-01-01T23:59:59.000Z

224

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

SciTech Connect (OSTI)

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

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

2010-04-26T23:59:59.000Z

225

Chromaticity of the lattice and beam stability in energy-recovery linacs  

SciTech Connect (OSTI)

Energy recovery linacs (ERLs) are an emerging generation of accelerators promising to revolutionize the fields of high-energy physics and photon sciences. These accelerators combine the advantages of linear accelerators with that of storage rings, and hold the promise of delivering electron beams of unprecedented power and quality. Use of superconducting radio-frequency (SRF) cavities converts ERLs into nearly perfect 'perpetuum mobile' accelerators, wherein the beam is accelerated to a desirable energy, used, and then gives the energy back to the RF field. One potential weakness of these devices is transverse beam break-up instability that could severely limit the available beam current. In this paper, I present a method of suppressing these dangerous effects using a natural phenomenon in the accelerators, viz., the chromaticity of the transverse motion.

Litvinenko, V.N.

2011-12-23T23:59:59.000Z

226

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

E-Print Network [OSTI]

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

Derwent, Paul; Lebedev, Valeri

2015-01-01T23:59:59.000Z

227

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

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

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.

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

2015-03-01T23:59:59.000Z

228

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

E-Print Network [OSTI]

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

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

2011-01-01T23:59:59.000Z

229

Managing coherence via put/get windows  

DOE Patents [OSTI]

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.

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

2011-01-11T23:59:59.000Z

230

Coherence properties of the radiation from FLASH  

E-Print Network [OSTI]

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.

Schneidmiller, E A

2015-01-01T23:59:59.000Z

231

Coherent neutrino scattering in dark matter detectors  

E-Print Network [OSTI]

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

Anderson, Alexander John

232

Managing coherence via put/get windows  

DOE Patents [OSTI]

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.

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

2012-02-21T23:59:59.000Z

233

Coherent regulation in yeast cell cycle network  

E-Print Network [OSTI]

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.

Nese Aral; Alkan Kabakcioglu

2014-12-14T23:59:59.000Z

234

Extended Coherence Time with Atom-Number Squeezed Sources  

E-Print Network [OSTI]

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

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

2006-09-02T23:59:59.000Z

235

Quantum Coherence in a Superfluid Josephson Junction  

SciTech Connect (OSTI)

We report a new kind of experiment in which we take an array of nanoscale apertures that form a superfluid {sup 4}He Josephson junction and apply quantum phase gradients directly along the array. We observe collective coherent behaviors from aperture elements, leading to quantum interference. Connections to superconducting and Bose-Einstein condensate Josephson junctions as well as phase coherence among the superfluid aperture array are discussed.

Narayana, Supradeep; Sato, Yuki [Rowland Institute at Harvard, Harvard University, Cambridge, Massachusetts 02142 (United States)

2011-02-04T23:59:59.000Z

236

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

E-Print Network [OSTI]

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

Danon, Yaron

237

Global coherence of dust density waves  

SciTech Connect (OSTI)

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.

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

2014-06-15T23:59:59.000Z

238

Store-operate-coherence-on-value  

DOE Patents [OSTI]

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.

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

2014-11-18T23:59:59.000Z

239

Beam dynamics studies of the 8 GeV Linac at FNAL  

SciTech Connect (OSTI)

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

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

2008-11-01T23:59:59.000Z

240

Cryogenic test of the 4 K / 2 K insert for the ARIEL e-Linac cryomodule  

SciTech Connect (OSTI)

The ARIEL project at TRIUMF requires a 50 MeV superconducting electron linac consisting of five nine cell 1.3 GHz cavities divided into three cryomodules with one, two and two cavities in each module respectively. LHe is distributed in parallel to each module at 4 K and at ?1.2 bar. Each module has a cryogenic insert on board that receives the 4 K liquid and produces 2 K into a cavity phase separator. The module combines a 4 K phase separator, a plate and fin heat exchanger from DATE and a J-T valve expanding into the 2 K phase separator. The unit also supplies 4 K liquid to thermal intercepts in the module in siphon loops that return the vaporized liquid to the 4 K reservoir. For testing purposes the unit is outfitted with a dummy 2 K phase separator and thermal intercepts with variable heaters that mimic the final heat loads in order to test the cryogenic performance. The design of the 4 K / 2 K insert, the results of the cold tests and a summary of the test infrastructure including cryogenics services will be presented.

Laxdal, R. E.; Ma, Y.; Harmer, P.; Kishi, D.; Koveshnikov, A.; Muller, N.; Vrielink, A. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC (Canada); O'Brien, M. [University of British Columbia, Vancouver (Canada); Ahammed, M. [Variable Energy Cyclotron Center, Kolkata (India)

2014-01-29T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Low-temperature thermodynamics with quantum coherence  

E-Print Network [OSTI]

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

Varun Narasimhachar; Gilad Gour

2014-10-02T23:59:59.000Z

242

Dental optical coherence domain reflectometry explorer  

DOE Patents [OSTI]

A hand-held, fiber optic based dental device with optical coherence domain reflectometry (OCDR) sensing capabilities provides a profile of optical scattering as a function of depth in the tissue at the point where the tip of the dental explorer touches the tissue. This system provides information on the internal structure of the dental tissue, which is then used to detect caries and periodontal disease. A series of profiles of optical scattering or tissue microstructure are generated by moving the explorer across the tooth or other tissue. The profiles are combined to form a cross-sectional, or optical coherence tomography (OCT), image.

Everett, Matthew J. (Livermore, CA); Colston, Jr., Billy W. (Livermore, CA); Sathyam, Ujwal S. (Livermore, CA); Da Silva, Luiz B. (Pleasanton, CA)

2001-01-01T23:59:59.000Z

243

PHASE COHERENCE PHENOMENA IN DISORDERED SUPERCONDUCTORS  

E-Print Network [OSTI]

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

Simons, Ben

244

Coherent states in the fermionic Fock space  

E-Print Network [OSTI]

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

Robert Oeckl

2015-01-09T23:59:59.000Z

245

Coherent Radiation Effects in the LCLS Undulator  

SciTech Connect (OSTI)

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.

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

2010-12-14T23:59:59.000Z

246

Interaction between the molecular coherent states for a discrete variable harmonic oscillator and the coherent radiation  

SciTech Connect (OSTI)

We used the dicrete variable three-dimmensional Charlier oscillator. For a system of molecules interacting with the coherent radiation field the temporal variation of the refractive index has been established.

Draganescu, Gheorghe Eugen [Department of Mechanics, Polytechnic University of Timisoara, Bd M Viteazu No1, Timisoara and Department of Physics, West University of Timisoara (Romania)

2012-08-17T23:59:59.000Z

247

Search for temporal coherence in the sky Erez N. Ribak  

E-Print Network [OSTI]

, related to longitudinal coherence by the speed of light c: c = lc / c. Generally, naturally occurring for naturally occurring coherence is in gravitational lensing by a small object, where the paths to the observer in astrophysical processes. Among others, synchrotron radiation, known to be polarized, can be also coherent over

Ribak, Erez

248

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

SciTech Connect (OSTI)

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.

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

2011-03-28T23:59:59.000Z

249

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

DOE Patents [OSTI]

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.

Douglas, David R. (York County, VA)

2012-01-10T23:59:59.000Z

250

Coherent Time-Delayed Atom-Light Interferometer  

E-Print Network [OSTI]

We present experimental observations of interference between an atomic spin coherence and an optical field in a $\\Lambda$-type gradient echo memory. The interference is mediated by a strong classical field that couples a weak probe field to the atomic spin coherence through a resonant Raman transition. Interference can be observed between a prepared spin coherence and another propagating optical field, or between multiple $\\Lambda$ transitions driving a single spin coherence. In principle, the interference in each scheme can yield a near unity visibility and could be used as a coherent all-optical switch.

Campbell, G; Sparkes, B M; Lam, P K; Buchler, B C

2011-01-01T23:59:59.000Z

251

COHERENT LASER VISION SYSTEM (CLVS) OPTION PHASE  

SciTech Connect (OSTI)

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.

Robert Clark

1999-11-18T23:59:59.000Z

252

Emergence of non-zonal coherent structures  

E-Print Network [OSTI]

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

Bakas, Nikolaos A

2015-01-01T23:59:59.000Z

253

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

SciTech Connect (OSTI)

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.

Guimei Wang

2011-12-31T23:59:59.000Z

254

Equatorial spread {ital F} effects on an HF path: Doppler spread, spatial coherence, and frequency coherence  

SciTech Connect (OSTI)

In August 1990 we participated in the Equatorial Ionospheric Studies sounding rocket campaign near Kwajalein Atoll in the equatorial Pacific region. The campaign included measurements of plasma density using rocket probes and coherent and incoherent scatter radar. During the campaign we fielded high-frequency ionospheric sounders over a bistatic path between Maloelap Atoll and Bikini Atoll in the Marshall Islands. The distance between the transmitters and receivers was 700 km; the ionospheric-reflection region was at 10.18; {degree}N, 168.40;{degree}E, near the magnetic equator. We made three types of measurements: Doppler spread and spatial coherence for a single-frequency CW path; frequency coherence of multiple CW paths; and Doppler spread and time-delay spread for a 60-kHz bandwidth path. We obtained such data over a period of 2 weeks for approximately 2 hours each evening; during this period spread {ital F} was common. Fifty percent of the evenings showed Doppler spread of greater than 6 Hz at the {minus}10 dB level (relative to the peak signal power) and greater than 15 Hz at the {minus}30 dB level. Forty percent of the evenings showed spatial coherence distance of less than 180 m in the direction normal to the bistatic path; 40{percent} of the evenings showed spatial coherence of less than 75 m in the direction parallel to the path. Seventy-five percent of the evenings showed coherence bandwidths of less than 1.5 kHz. {copyright} 1999 American Geophysical Union

Fitzgerald, T.J.; Argo, P.E.; Carlos, R.C. [Los Alamos National Laboratory, Los Alamos, New Mexico (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico (United States)

1999-01-01T23:59:59.000Z

255

On-site Real-Time Inspection System for Pump-impeller using X-band Linac X-ray Source  

SciTech Connect (OSTI)

The methods of nondestructive testing (NDT) are generally ultrasonic, neutron, eddy-current and X-rays, NDT by using X-rays, in particular, is the most useful inspection technique having high resolution. We can especially evaluate corroded pipes of petrochemical complex, nuclear and thermal-power plants by the high energy X-ray NDT system. We develop a portable X-ray NDT system with X-band linac and magnetron. This system can generate a 950 keV electron beam. We are able to get X-ray images of samples with 1 mm spatial resolution. This system has application to real time impeller inspection because linac based X-ray sources are able to generate pulsed X-rays. So, we can inspect the rotating impeller if the X-ray pulse rate is synchronized with the impeller rotation rate. This system has application in condition based maintenance (CBM) of nuclear plants, for example. However, 950 keV X-ray source can only be used for thin tubes with 20 mm thickness. We have started design of a 3.95 MeV X-band linac for broader X-ray NDT application. We think that this X-ray NDT system will be useful for corrosion wastage and cracking in thicker tubes at nuclear plants and impeller of larger pumps. This system consists of X-band linac, thermionic cathode electron gun, magnetron and waveguide components. For achieving higher electric fields the 3.95 MeV X-band linac structure has the side-coupled acceleration structure. This structure has more efficient acceleration than the 950 keV linac with alternating periodic structure (APS). We adopt a 1.3 MW magnetron for the RF source. This accelerator system is about 30 cm long. The beam current is about 150 mA, and X-ray dose rate is 10 Gy at 1 m/500 pps. In this paper, the detail of the whole system concept and the electromagnetic field of designed linac structure will be reported.

Yamamoto, Tomohiko; Natsui, Takuya; Taguchi, Hiroki; Taniguchi, Yoshihiro; Lee, Ki woo; Hashimoto, Eiko; Sakamoto, Fumito; Sakumi, Akira; Yusa, Noritaka; Uesaka, Mitsuru [Nuclear Professional School, the University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki (Japan); Nakamura, Naoki; Yamamoto, Masashi; Tanabe, Eiji [Accuthera Inc. 2-7-6 Kurigi, Asao, Kawasaki, Kanagawa 215-0033 Japan (Japan)

2009-03-10T23:59:59.000Z

256

D-dimensional Smorodinsky-Winternitz potential: Coherent state approach  

SciTech Connect (OSTI)

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.

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

2013-10-15T23:59:59.000Z

257

The coordinate coherent states approach revisited  

SciTech Connect (OSTI)

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

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

2013-02-15T23:59:59.000Z

258

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

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

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

259

The role of pump coherence in two-photon interferometry  

E-Print Network [OSTI]

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.

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

2010-12-20T23:59:59.000Z

260

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

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

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

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

On solving multistage stochastic programs with coherent risk ...  

E-Print Network [OSTI]

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

A. B. Philpott

2012-08-13T23:59:59.000Z

262

Coherent Transition Radiation in Askaryan radio detectors  

E-Print Network [OSTI]

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

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

2015-01-01T23:59:59.000Z

263

Self-Similar Modes of Coherent Diffusion  

E-Print Network [OSTI]

Self-similar solutions of the coherent diffusion equation are derived and measured. The set of real similarity solutions is generalized by the introduction of a nonuniform phase surface, based on the elegant Gaussian modes of optical diffraction. In an experiment of light storage in a gas of diffusing atoms, a complex initial condition is imprinted, and its diffusion dynamics is monitored. The self-similarity of both the amplitude and the phase pattern is demonstrated, and an algebraic decay associated with the mode order is measured. Notably, as opposed to a regular diffusion spreading, a self-similar contraction of a special subset of the solutions is predicted and observed.

O. Firstenberg; P. London; D. Yankelev; R. Pugatch; M. Shuker; N. Davidson

2010-08-16T23:59:59.000Z

264

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New Substation Sites Proposed Route BTRIC CNMSMethanol SteamNOTICE:PracticesCOHERENT

265

Optical coherence tomography guided dental drill  

DOE Patents [OSTI]

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.

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

2002-01-01T23:59:59.000Z

266

Proposal to search for a dark photon in $e^+$ on target collisions at DA$?$NE linac  

E-Print Network [OSTI]

Photon-like particles are predicted in many extensions of the Standard Model. They have interactions similar to the photon, are vector bosons, and can be produced together with photons. The present paper proposes a search for such particles in the $ e^+e^- \\to U\\gamma$ process in a positron-on-target experiment, exploiting the positron beam of the DA$\\Phi$NE linac at the Laboratori Nazionali di Frascati, INFN. In one year of running a sensitivity in the relative interaction strength down to $\\sim10^{-6}$ is achievable, in the mass region from 2.5 MeV$

Mauro Raggi; Venelin Kozhuharov

2014-07-16T23:59:59.000Z

267

Catheter guided by optical coherence domain reflectometry  

DOE Patents [OSTI]

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.

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

2002-01-01T23:59:59.000Z

268

Quantum process tomography with coherent states  

E-Print Network [OSTI]

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

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

2010-09-17T23:59:59.000Z

269

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

E-Print Network [OSTI]

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

Brown, Emery N.

270

The Quasi-Coherent Oscillations of SS Cygni  

E-Print Network [OSTI]

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

Christopher W. Mauche

1996-08-22T23:59:59.000Z

271

Optical quantum swapping in a coherent atomic medium  

E-Print Network [OSTI]

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

Aurelien Dantan

2011-10-03T23:59:59.000Z

272

Mode coherence at megameter ranges in the North Pacific Ocean  

E-Print Network [OSTI]

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

Wage, Kathleen

273

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

274

Coherent Quantum-Noise Cancellation for Optomechanical Sensors  

E-Print Network [OSTI]

Using a flowchart representation of quantum optomechanical dynamics, we design coherent quantum-noise-cancellation schemes that can eliminate the back-action noise induced by radiation pressure at all frequencies and thus overcome the standard quantum limit of force sensing. The proposed schemes can be regarded as novel examples of coherent feedforward quantum control.

Mankei Tsang; Carlton M. Caves

2010-08-17T23:59:59.000Z

275

Unsupervised extraction of coherent regions for image based rendering  

E-Print Network [OSTI]

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

Dragotti, Pier Luigi

276

Coherent spinor dynamics in a spin-1 Bose condensate  

E-Print Network [OSTI]

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

Loss, Daniel

277

Conditions for two-photon interference with coherent pulses  

E-Print Network [OSTI]

We study the conditions for two-photon classical interference with coherent pulses. We find that the temporal overlap between optical pulses is not required for interference However, coherence within the same inputs is found to be essential for the interference.

Yong-Su Kim; Oliver Slattery; Paulina S. Kuo; Xiao Tang

2013-06-27T23:59:59.000Z

278

Generation of Coherent Institute for Perception Research (IPO)  

E-Print Network [OSTI]

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

Theune, Mariët

279

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

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

280

Eddy impacts on the Florida Current E. Frajka-Williams,1  

E-Print Network [OSTI]

Eddy impacts on the Florida Current E. Frajka-Williams,1 W. E. Johns,2 C. S. Meinen,3 L. M. Beal,2. Meinen, L. M. Beal, and S. A. Cunningham (2013), Eddy impacts on the Florida Current, Geophys. Res. Lett, the FC is coherent with local winds [Schott et al., 1988; Atkinson et al., 2010; Rousset and Beal, 2011

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Quantum coherence, time-translation symmetry and thermodynamics  

E-Print Network [OSTI]

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.

Matteo Lostaglio; Kamil Korzekwa; David Jennings; Terry Rudolph

2015-04-13T23:59:59.000Z

282

E-Print Network 3.0 - adaptive-optics optical coherence Sample...  

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

optics optical coherence Search Powered by Explorit Topic List Advanced Search Sample search results for: adaptive-optics optical coherence Page: << < 1 2 3 4 5 > >> 1 NW...

283

Swept source optical coherence microscopy for pathological assessment of cancerous tissues  

E-Print Network [OSTI]

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 ...

Ahsen, Osman Oguz

2013-01-01T23:59:59.000Z

284

Unambiguous coherent state identification: Searching a quantum database  

E-Print Network [OSTI]

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.

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

2007-07-23T23:59:59.000Z

285

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

E-Print Network [OSTI]

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

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

2012-01-01T23:59:59.000Z

286

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

E-Print Network [OSTI]

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

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

2013-02-09T23:59:59.000Z

287

Coherent structures in compressible free-shear-layer flows  

SciTech Connect (OSTI)

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.

Aeschliman, D.P.; Baty, R.S. [Sandia National Labs., Albuquerque, NM (United States). Engineering Sciences Center; Kennedy, C.A.; Chen, J.H. [Sandia National Labs., Livermore, CA (United States). Combustion and Physical Sciences Center

1997-08-01T23:59:59.000Z

288

Origin of Long Lived Coherences in Light-Harvesting Complexes  

E-Print Network [OSTI]

A vibronic exciton model is developed to investigate the origin of long lived coherences in light-harvesting complexes. Using experimentally determined parameters and uncorrelated site energy fluctuations, the model predicts oscillations in the nonlinear spectra of the Fenna-Matthews-Olson (FMO) complex with a dephasing time of 1.3 ps at 77 K. These oscillations correspond to the coherent superposition of vibronic exciton states with dominant contributions from vibrational excitations on the same pigment. Purely electronic coherences are found to decay on a 200 fs timescale.

Niklas Christensson; Harald F. Kauffmann; Tonu Pullerits; Tomas Mancal

2012-01-30T23:59:59.000Z

289

Coherent state of a weakly interacting ultracold Fermi gas  

E-Print Network [OSTI]

We examine the weakly interacting atoms in an ultracold Fermi gas leading to a state of macroscopic coherence, from a theoretical perspective. It has been shown that this state can be described as a fermionic coherent state. These coherent states are the eigenstates of fermionic annihilation operators, the eigenvalues being anti-commuting numbers or Grassmann numbers. By exploiting the simple rules of Grassmann algebra and a close kinship between relations evaluated for more familiar bosonic fields and those for fermionic fields, we derive the thermodynamic limit, the spontaneous symmetry breaking and the quasi-particle spectrum of the fermionic system.

Arnab Ghosh; Sudarson Sekhar Sinha; Deb Shankar Ray

2013-04-04T23:59:59.000Z

290

Coherent excitation of a single atom to a Rydberg state  

SciTech Connect (OSTI)

We present the coherent excitation of a single Rubidium atom to the Rydberg state 58d{sub 3/2} using a two-photon transition. The experimental setup is described in detail, as are experimental techniques and procedures. The coherence of the excitation is revealed by observing Rabi oscillations between ground and Rydberg states of the atom. We analyze the observed oscillations in detail and compare them to numerical simulations which include imperfections of our experimental system. Strategies for future improvements on the coherent manipulation of a single atom in our settings are given.

Miroshnychenko, Y.; Gaeetan, A.; Evellin, C.; Grangier, P.; Wilk, T.; Browaeys, A. [Laboratoire Charles Fabry, Institut d'Optique, Centre National de la Recherche Scientifique, Universite Paris-Sud, Campus Polytechnique, RD 128, F-91127 Palaiseau CEDEX (France); Comparat, D.; Pillet, P. [Laboratoire Aime Cotton, Centre National de la Recherche Scientifique, Universite Paris-Sud, Batiment 505, Campus d'Orsay, F-91405 Orsay CEDEX (France)

2010-07-15T23:59:59.000Z

291

Atmospheric Lagrangian coherent structures considering unresolved turbulence and forecast uncertainty  

E-Print Network [OSTI]

Atmospheric Lagrangian coherent structures considering unresolved turbulence and forecast structures Stochastic trajectory Stochastic FTLE field Ensemble forecasting Uncertainty analysis a b s t r of the forecast FTLE fields is analyzed using ensemble forecasting. Unavoidable errors of the forecast velocity

Ross, Shane

292

Temperature-dependent coherent oscillation in photorefractive relaxor strontium barium  

E-Print Network [OSTI]

Temperature-dependent coherent oscillation in photorefractive relaxor strontium barium niobate M of the photorefractive light-induced scattering (beam fanning) in Sr0.61Ba0.39Nb2O6 (strontium barium niobate) doped

Osnabrück, Universität

293

Coherence characterization with a superconducting flux qubit through NMR approaches  

E-Print Network [OSTI]

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 ...

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

2013-01-01T23:59:59.000Z

294

Low-coherent WDM reflectometry for accurate fiber length monitoring  

E-Print Network [OSTI]

A fiber-optic low-coherent reflectometer was developed to accurately monitor fiber length variation. A large length-coverage range was obtained by using a fiber Bragg grating array in a wavelength-division-multiplexing ...

Hui, Rongqing; Thomas, J.; Allen, Christopher Thomas; Fu, B.; Gao, S.

2003-01-01T23:59:59.000Z

295

Magnetism studies using resonant, coherent, x-ray scattering...  

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

Magnetism studies using resonant, coherent, x-ray scattering Monday, September 10, 2012 - 10:00am SLAC, Bldg. 137, Room 226 Keoki Seu Seminar: With the advent of free electron...

296

Water Window Ptychographic Imaging with Characterized Coherent X-rays  

E-Print Network [OSTI]

We report on a ptychographical coherent diffractive imaging experiment in the water window with focused soft X-rays at $500~\\mathrm{eV}$. An X-ray beam with high degree of coherence was selected for ptychography at the P04 beamline of the PETRA III synchrotron radiation source. We measured the beam coherence with the newly developed non-redundant array method. A pinhole $2.6~\\mathrm{\\mu m}$ in size selected the coherent part of the beam and was used for ptychographic measurements of a lithographically manufactured test sample and fossil diatom. The achieved resolution was $53~\\mathrm{nm}$ for the test sample and only limited by the size of the detector. The diatom was imaged at a resolution better than $90~\\mathrm{nm}$.

Rose, Max; Dzhigaev, Dmitry; Gorobtsov, Oleg; Senkbeil, Tobias; von Gundlach, Andreas; Gorniak, Thomas; Shabalin, Anatoly; Viefhaus, Jens; Rosenhahn, Axel; Vartanyants, Ivan

2015-01-01T23:59:59.000Z

297

Development of Molecular Contrast in Coherence Domain Optical Imaging  

E-Print Network [OSTI]

. This technique could be used potentially as a clinical tool for diagnosing different progression stages of melanoma. This technique could also be applied to differentiate other mixed chromophores. Second harmonic optical coherence tomography (SHOCT) is non...

Wan, Qiujie

2012-02-14T23:59:59.000Z

298

Optimizing directory-based cache coherence on the RAW architecture  

E-Print Network [OSTI]

Caches help reduce the effect of long-latency memory requests, by providing a high speed data-path to local memory. However, in multi-processor systems utilizing shared memory, cache coherence protocols are necessary to ...

Ramaswamy, Satish

2005-01-01T23:59:59.000Z

299

Doppler optical coherence microscopy for studies of cochlear mechanics  

E-Print Network [OSTI]

The possibility of measuring subnanometer motions with micron scale spatial resolution in the intact mammalian cochlea using Doppler optical coherence microscopy (DOCM) is demonstrated. A novel DOCM system is described ...

Hong, Stanley S.

300

The minimum-uncertainty coherent states for Landau levels  

SciTech Connect (OSTI)

The Glauber minimum-uncertainty coherent states with two variables for Landau levels, based on the representation of Weyl-Heisenberg algebra by two different modes, have been studied about four decades ago. Here, we introduce new two-variable coherent states with minimum uncertainty relationship for Landau levels in three different methods: the infinite unitary representation of su(1, 1) is realized in two different methods, first, by consecutive levels with the same energy gaps and also with the same value for z-angular momentum quantum number, then, by shifting z-angular momentum mode number by two units while the energy level remaining the same. Besides, for su(2), whether by lowest Landau levels or Landau levels with lowest z-angular momentum, just one finite unitary representation is introduced. Having constructed the generalized Klauder-Perelomov coherent states, for any of the three representations, we obtain their Glauber coherency by displacement operator of Weyl-Heisenberg algebra.

Dehghani, A. [Physics Department, Payame Noor University, P. O. Box 19395-4697 Tehran (Iran, Islamic Republic of); Fakhri, H. [Department of Theoretical Physics and Astrophysics, Faculty of Physics, University of Tabriz, P. O. Box 51666-16471 Tabriz (Iran, Islamic Republic of); Mojaveri, B. [Department of Physics, Azarbaijan Shahid Madani University, P. O. Box 51745-406 Tabriz (Iran, Islamic Republic of)

2012-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Documentation Integrity for Safety-Critical Applications: The COHERE Project  

E-Print Network [OSTI]

. Keywords Authoring interface, documentation integrity, consistency 1. INTRODUCTION This paper reportsDocumentation Integrity for Safety-Critical Applications: The COHERE Project David G. Novick-critical systems. Following a set of documentation integrity maxims, the project developed two generations

Novick, David G.

302

Ecological coherence of Natura2000 protected areas in Scotland   

E-Print Network [OSTI]

important for ecological coherence (representivity, replication, patch sizes and shapes, and connectivity). In this study, a method is presented that addresses all of the above criteria for three main Annex I habitats in Scotland (Caledonian woodland, Tilio...

Winstrup, Mie

2012-11-29T23:59:59.000Z

303

Computational imaging for 3D phase and coherence retrieval |...  

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

Computational imaging for 3D phase and coherence retrieval Wednesday, December 10, 2014 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Speaker: Laura Waller (UC Berkeley) Program...

304

Coherent feedback that beats all measurement-based feedback protocols  

E-Print Network [OSTI]

We show that when the speed of control is bounded, there is a widely applicable minimal-time control problem for which a coherent feedback protocol is optimal, and is faster than all measurement-based feedback protocols, ...

Jacobs, Kurt

305

Finite blocklength analysis of the MISO Coherent Block Fading Channel  

E-Print Network [OSTI]

The Coherent MISO Block Fading Channel is a wireless communication channel model in which the transmitter has access to multiple antennas while the receiver has access to one. This model is becoming increasingly important ...

Collins, Austin Daniel

2014-01-01T23:59:59.000Z

306

Quantum Coherence Effects in Novel Quantum Optical Systems  

E-Print Network [OSTI]

and find interesting applications. We show that quantum coherence can lead to transient Raman lasing and lasing without inversion in short wavelength spectral regions--extreme ultraviolet and x-ray--without the requirement of incoherent pumping. For example...

Sete, Eyob Alebachew

2012-10-19T23:59:59.000Z

307

Quantum coherence, time-translation symmetry and thermodynamics  

E-Print Network [OSTI]

The first law of thermodynamics imposes not just a constraint on the energy-content of systems in extreme quantum regimes, but also symmetry-constraints related to the thermodynamic processing of quantum coherence. Harmonic analysis allows any density operator to be decomposed in terms of mode operators which quantify the coherence present in a state in a natural way. We establish upper and lower bounds for the evolution of such modes under arbitrary thermal operations, and analyse primitive coherence manipulations. Well-studied thermo-majorization relations on block-diagonal quantum states correspond to constraints only on the zero-mode of a state, governing energy transfers. A complete set of constraints for non-zero modes, governing coherence transfers, is at present unknown, but these modes are found to display similar irreversibility, which demands greater study.

Matteo Lostaglio; Kamil Korzekwa; David Jennings; Terry Rudolph

2014-10-16T23:59:59.000Z

308

Coherent radar ice thickness measurements over the Greenland ice sheet  

E-Print Network [OSTI]

We developed two 150-MHz coherent radar depth sounders for ice thickness measurements over the Greenland ice sheet. We developed one of these using connectorized components and the other using radio frequency integrated circuits (RFICs). Both...

Gogineni, S. Prasad; Tammana, Dilip; Braaten, David A.; Leuschen, C.; Legarsky, J.; Kanagaratnam, P.; Stiles, J.; Allen, C.; Jezek, K.; Akins, T.

2001-12-27T23:59:59.000Z

309

anatomical optical coherence: Topics by E-print Network  

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

Ivan; Wang, Yimin; Chen, Zhongping 2004-01-01 3 Coherent Communication with Linear Optics Quantum Physics (arXiv) Summary: We show how to implement several continuous-variable...

310

Studying coherence in ultra-cold atomic gases  

E-Print Network [OSTI]

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 ...

Miller, Daniel E. (Daniel Edward)

2007-01-01T23:59:59.000Z

311

Femtosecond time-resolved spectroscopy of coherent oscillations in nanomaterials  

E-Print Network [OSTI]

FEMTOSECOND TIME-RESOLVED SPECTROSCOPY OF COHERENT OSCILLATIONS IN NANOMATERIALS A Dissertation by SERGUEI JEREBTSOV Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of DOCTOR OF PHILOSOPHY May 2007 Major Subject: Physics FEMTOSECOND TIME-RESOLVED SPECTROSCOPY OF COHERENT OSCILLATIONS IN NANOMATERIALS A Dissertation by SERGUEI JEREBTSOV Submitted to the Office of Graduate Studies of Texas A&M University in partial...

Jerebtsov, Serguei Nikolaevich

2009-05-15T23:59:59.000Z

312

Coherent flash of light emitted by a cold atomic cloud  

SciTech Connect (OSTI)

When a resonant laser sent on an optically thick cold atomic cloud is abruptly switched off, a coherent flash of light is emitted in the forward direction. This transient phenomenon is observed due to the highly resonant character of the atomic scatterers. We analyze quantitatively its temporal properties and show very good agreement with theoretical predictions. Based on complementary experiments, the phase of the coherent field is reconstructed without interferometric tools.

Chalony, M. [Institut Non Lineaire de Nice, Universite de Nice Sophia-Antipolis, CNRS, F-06560 Valbonne (France); Pierrat, R. [Institut Langevin, ESPCI ParisTech, CNRS UMR 7587, 10 rue Vauquelin, F-75005 Paris (France); Delande, D. [Laboratoire Kastler Brossel, UPMC-Paris 6, ENS, CNRS, 4 Place Jussieu, F-75005 Paris (France); Wilkowski, D. [Institut Non Lineaire de Nice, Universite de Nice Sophia-Antipolis, CNRS, F-06560 Valbonne (France); Centre for Quantum Technologies, National University of Singapore, 117543 Singapore (Singapore)

2011-07-15T23:59:59.000Z

313

Wide-band coherent receiver development for enhanced surveillance  

SciTech Connect (OSTI)

Oak Ridge National Laboratory (ORNL) has been developing advanced coherent IR heterodyne receivers for plasma diagnostics in fusion reactors for over 20 years. Recent progress in wide band IR detectors and high speed electronics has significantly enhanced the measurement capabilities of coherent receivers. In addition, developments in new HgCdTe and quantum well IR photodetector (QWIP) focal plane arrays are providing the possibility of both active and passive coherent imaging. In this paper the authors discuss the implications of these new enabling technologies to the IR remote sensing community for enhanced surveillance. Coherent receivers, as opposed to direct or thermal detection, provide multiple dimensions of information about a scene or target in a single detector system. Combinations of range, velocity, temperature, and chemical species information are all available from a coherent heterodyne receiver. They present laboratory data showing measured noise equivalent power (NEP) of new QWIP detectors with heterodyne bandwidths greater than 7 GHz. For absorption measurements, a wide band coherent receiver provides the capability of looking between CO{sub 2} lines at off-resonance peaks and thus the measurement of lines normally inaccessible with conventional heterodyne or direct detection systems. Also described are differential absorption lidar (DIAL) and Doppler laboratory measurements using an 8 x 8 HgCdTe focal plane array demonstrating the snapshot capability of coherent receiver detector arrays for enhanced chemical plume and moving hardbody capture. Finally they discuss a variety of coherent receiver configurations that can suppress (or enhance) sensitivity of present active remote sensing systems to speckle, glint, and other measurement anomalies.

Simpson, M.L.; Richards, R.K.; Hutchinson, D.P.

1998-03-01T23:59:59.000Z

314

Coherent feedback that beats all measurement-based feedback protocols  

E-Print Network [OSTI]

We show that when the speed of control is bounded, there is a widely applicable minimal-time control problem for which a coherent feedback protocol is optimal, and is faster than all measurement-based feedback protocols, where the latter are defined in a strict sense. The superiority of the coherent protocol is due to the fact that it can exploit a geodesic path in Hilbert space, a path that measurement-based protocols cannot follow.

Kurt Jacobs; Xiaoting Wang; Howard M. Wiseman

2014-07-21T23:59:59.000Z

315

Coherent testing and simulation of composite blade repair  

E-Print Network [OSTI]

COHERENT TESTING AND SIMULATION OF COMPOSITE BLADE REPAIR A Thesis by BRIAN GLENN MCNICHOLS 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... December 1997 Major Subject: Mechanical Engineering COHERENT TESTING AND SIMULATION OF COMPOSITE BLADE REPAIR A Thesis by BRIAN GLENN MCNICHOLS Submitted to Texas A&M University In partial fulfillment of the requirements for the degree of MASTER...

McNichols, Brian Glenn

2012-06-07T23:59:59.000Z

316

A Coherent Perceptron for All-Optical Learning  

E-Print Network [OSTI]

We present nonlinear photonic circuit models for constructing programmable linear transformations and use these to realize a coherent Perceptron, i.e., an all-optical linear classifier capable of learning the classification boundary iteratively from training data through a coherent feedback rule. Through extensive semi-classical stochastic simulations we demonstrate that the device nearly attains the theoretical error bound for a model classification problem.

Nikolas Tezak; Hideo Mabuchi

2015-03-28T23:59:59.000Z

317

A Coherent Perceptron for All-Optical Learning  

E-Print Network [OSTI]

We present nonlinear photonic circuit models for constructing programmable linear transformations and use these to realize a coherent Perceptron, i.e., an all-optical linear classifier capable of learning the classification boundary iteratively from training data through a coherent feedback rule. Through extensive semi-classical stochastic simulations we demonstrate that the device nearly attains the theoretical error bound for a model classification problem.

Tezak, Nikolas

2015-01-01T23:59:59.000Z

318

Electron Beam Diagnostics using Coherent Cherenkov Radiation in Aerogel  

SciTech Connect (OSTI)

The use of coherent Cherenkov radiation as a diagnostic tool for longitudinal distribution of an electron beam is studied in this paper. Coherent Cherenkov radiation is produced in an aerogel with an index of refraction close to unity. An aerogel spectral properties are experimentally studied and analyzed. This method will be employed for the helical IFEL bunching experiment at Neptune linear accelerator facility at UCLA.

Tikhoplav, R.; Knyazik, A.; Rosenzweig, J. B. [UCLA Physics Dept., Los Angeles, CA 90066 (United States); Ruelas, M. [RadiaBeam Technologies, Marina Del Ray, CA 90292 (United States)

2009-01-22T23:59:59.000Z

319

Fabrication, Tuning, Treatment and Testing of Two 3.5 Cell Photo-Injector Cavities for the ELBE Linac  

SciTech Connect (OSTI)

As part of a CRADA (Cooperative Research and Development Agreement) between Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and Thomas Jefferson Lab National Accelerator Facility (TJNAF) we have fabricated and tested two 1.3 GHz 3.5 cell photo-injector cavities from polycrystalline RRR niobium and large grain RRR niobium, respectively. The cavity with the better performance will replace the presently used injector cavity in the ELBE linac. The cavities have been fabricated and pre-tuned at TJNAF, while the more sophisticated final field tuning, the adjustment of the external couplings and the field profile measurement of transverse electric modes for RF focusing was done at HZDR. The following standard surface treatment and the vertical test was carried out at TJNAF's production facilities. A major challenge turned out to be the rinsing of the cathode cell, which has small opening (O-slash10mm) to receive the cathode stalk. Another unexpected problem encountered after etching, since large visible defects appeared in the least accessible cathode cell. This contribution reports about our experiences, initial results and the on-going diagnostic work to understand and fix the problems.

Arnold, A. [HZDR, Dresden (Germany); Murcek, P. [HZDR, Dresden (Germany); Teichert, J. [HZDR, Dresden (Germany); Xiang, R. [HZDR, Dresden (Germany); Eremeev, G. V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Kneisel, P. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Stirbet, M. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Turlington, L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

2011-07-01T23:59:59.000Z

320

Fabrication, Tuning, Treatment and Testing of Two 3.5 Cell Photo-Injektor Cavities for the ELBE Linac  

E-Print Network [OSTI]

As part of a CRADA (Cooperative Research and Development Agreement) between Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and Thomas Jefferson Lab National Accelerator Facility (TJNAF) we have fabricated and tested two 1.3 GHz 3.5 cell photo-injector cavities from polycrystalline RRR niobium and large grain RRR niobium, respectively. The cavity with the better performance will replace the presently used injector cavity in the ELBE linac [1]. The cavities have been fabricated and pre-tuned at TJNAF, while the more sophisticated final field tuning; the adjustment of the external couplings and the field profile measurement of transverse electric modes for RF focusing [2] was done at HZDR. The following standard surface treatment and the vertical test were carried out at TJNAF’s production facilities. A major challenge turned out to be the rinsing of the cathode cell, which has small opening (Ø10 mm) to receive the cathode stalk. Another unexpected problem encountered after etching, since large visible defects a...

Arnold, A; Teichert, J; Xiang, R; Eremeev, G V; Kneisel, P; Stirbet, M; Turlington, L

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Impact of the spatial laser distribution on photocathode gun operation  

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

It is widely believed that a drive laser with uniform temporal and spatial laser profiles is required to generate the lowest emittance beam at the photoinjector. However, for a given 3 ps smooth-Gaussian laser temporal profile, our recent simulations indicate that a truncated-Gaussian laser spatial profile produces an electron beam with smaller emittance. The simulation results are qualitatively confirmed by later analytical calculation, and also confirmed by measurements: emittance reduction of ?25% was observed at the linac coherent light source (LCLS) injector with a truncated-Gaussian laser spatial profile at the nominal operating bunch charge of 150 pC. There was a significant secondary benefit—laser transmission through the iris for the truncated-Gaussian profile was about twice that compared to the nearly uniform distribution, which significantly loosens the laser power and quantum efficiency requirements for drive laser system and photocathode. Since February 9, 2012, the drive laser with the truncated-Gaussian spatial distribution has been used for LCLS routine user operations and the corresponding free electron laser power is at least the same as the one when using the nearly uniform spatial profile.

Zhou, Feng; Brachmann, Axel; Emma, Paul; Gilevich, Sasha; Huang, Zhirong

2012-09-01T23:59:59.000Z

322

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

SciTech Connect (OSTI)

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.

Esmaeeli, A. D., E-mail: ali-esmaeeli-d@yahoo.com [Department of Physics, Rasht Branch, Islamic Azad University, Rasht, 41476-54919 (Iran, Islamic Republic of); Mahdavi, S. R. [Department of Medical Physics, Tehran University of Medical Sciences, Tehran, 14174 (Iran, Islamic Republic of)] [Department of Medical Physics, Tehran University of Medical Sciences, Tehran, 14174 (Iran, Islamic Republic of); Pouladian, M.; Bagheri, S. [Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, 14778-93855 (Iran, Islamic Republic of)] [Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, 14778-93855 (Iran, Islamic Republic of); Monfared, A. S. [Department of Medical Physics, Babol University of Medical Sciences, Babol, 47148-71167 (Iran, Islamic Republic of)] [Department of Medical Physics, Babol University of Medical Sciences, Babol, 47148-71167 (Iran, Islamic Republic of)

2014-01-15T23:59:59.000Z

323

Prudence in estimating coherence between planetary, solar and climate oscillations  

E-Print Network [OSTI]

There are claims that there is correlation between the speed of center of mass of the solar system and the global temperature anomaly. This is partly grounded in data analysis and partly in a priori expectations. The magnitude squared coherence function is the proper measure for testing such claims. It is not hard to produce high coherence estimates at periods around 15--22 and 50--60 years between these data sets. This is done in two independent ways, by wavelets and by a periodogram method. But does a coherence of high value mean that there is coherence of high significance? In order to investigate that, four different measures for significance are studied. Due to the periodic nature of the data, only Monte Carlo simulation based on a non-parametric random phase method is appropriate. None of the high values of coherence then turn out to be significant. Coupled with a lack of a physical mechanism that can connect these phenomena, the planetary hypothesis is therefore dismissed.

Holm, Sverre

2015-01-01T23:59:59.000Z

324

Dynamics of disentanglement, density matrix, and coherence in neutrino oscillations  

SciTech Connect (OSTI)

In charged current weak interaction processes, neutrinos are produced in an entangled state with the charged lepton. This correlated state is disentangled by the measurement of the charged lepton in a detector at the production site. We study the dynamical aspects of disentanglement, propagation, and detection, in particular, the conditions under which the disentangled state is a coherent superposition of mass eigenstates. The appearance and disappearance far-detection processes are described from the time evolution of this disentangled 'collapsed' state. The familiar quantum mechanical interpretation and factorization of the detection rate emerges when the quantum state is disentangled on time scales much shorter than the inverse oscillation frequency, in which case the final detection rate factorizes in terms of the usual quantum mechanical transition probability provided the final density of states is insensitive to the neutrino energy difference. We suggest possible corrections for short-baseline experiments. If the charged lepton is unobserved, neutrino oscillations and coherence are described in terms of a reduced density matrix obtained by tracing out an unobserved charged lepton. The diagonal elements in the mass basis describe the production of mass eigenstates whereas the off-diagonal ones provide a measure of coherence. It is shown that coherences are of the same order of the diagonal terms on time scales up to the inverse oscillation frequency, beyond which the coherences oscillate as a result of the interference between mass eigenstates.

Wu Jun; Boyanovsky, Daniel [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Hutasoit, Jimmy A.; Holman, Richard [Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

2010-07-01T23:59:59.000Z

325

HOM damping properties of fundamental power couplers in the superconducting electron gun of the energy recovery LINAC at Brookhaven National Laboratory  

SciTech Connect (OSTI)

Among the accelerator projects under construction at the Relativistic Heavy Ion Collider (RHIC) is an R and D energy recovery LINAC (ERL) test facility. The ERL includes both a five-cell superconducting cavity as well as a superconducting, photoinjector electron gun. Because of the high-charge and high-current demands, effective higher-order mode (HOM) damping is essential, and several strategies are being pursued. Among these is the use of the fundamental power couplers as a means for damping some HOMs. Simulation studies have shown that the power couplers can play a substantial role in damping certain HOMs, and this presentation discusses these studies along with measurements.

Hammons, L.; Hahn, H.

2011-03-28T23:59:59.000Z

326

Coherent Atom Optics with fast metastable rare gas atoms  

SciTech Connect (OSTI)

Coherent atom optics experiments making use of an ultra-narrow beam of fast metastable atoms generated by metastability exchange are reported. The transverse coherence of the beam (coherence radius of 1.7 {mu}m for He*, 1.2 {mu}m for Ne*, 0.87 {mu}m for Ar*) is demonstrated via the atomic diffraction by a non-magnetic 2{mu}m-period reflection grating. The combination of the non-scalar van der Waals (vdW) interaction with the Zeeman interaction generated by a static magnetic field gives rise to ''vdW-Zeeman'' transitions among Zeeman sub-levels. Exo-energetic transitions of this type are observed with Ne*(3P2) atoms traversing a copper micro-slit grating. They can be used as a tunable beam splitter in an inelastic Fresnel bi-prism atom interferometer.

Grucker, J.; Baudon, J.; Karam, J.-C.; Perales, F.; Vassilev, G.; Ducloy, M. [Laboratoire de Physique des Lasers, Universite Paris 13, Avenue J.B. Clement, 93430-Villetaneuse (France); Bocvarski, V. [Institute of Physics, Pregrevica 118, 11080 - Belgrade-Zemun (Serbia and Montenegro)

2006-12-01T23:59:59.000Z

327

Method and apparatus for coherent imaging of infrared energy  

DOE Patents [OSTI]

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.

Hutchinson, D.P.

1998-05-12T23:59:59.000Z

328

Method and apparatus for coherent imaging of infrared energy  

DOE Patents [OSTI]

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.

Hutchinson, Donald P. (Knoxville, TN)

1998-01-01T23:59:59.000Z

329

Chaos induced coherence in two independent food chains  

E-Print Network [OSTI]

Coherence evolution of two food web models can be obtained under the stirring effect of chaotic advection. Each food web model sustains a three--level trophic system composed of interacting predators, consumers and vegetation. These populations compete for a common limiting resource in open flows with chaotic advection dynamics. Here we show that two species (the top--predators) of different colonies chaotically advected by a jet--like flow can synchronize their evolution even without migration interaction. The evolution is charaterized as a phase synchronization. The phase differences (determined through the Hilbert transform) of the variables representing those species show a coherent evolution.

Adriana Auyuanet; Arturo C. Marti; Raul Montagne

2005-07-20T23:59:59.000Z

330

Uncertainties of coherent states for a generalized supersymmetric annihilation operator  

SciTech Connect (OSTI)

This study presents supersymmetric coherent states that are eigenstates of a general four-parameter family of annihilation operators. The elements of this family are defined as operators in Fock space that transform a subspace of a definite number of particles into a subspace with one particle removed. The emphasis is on classifying parameter space in various regions according to the uncertainty bounds of the corresponding coherent states. Specifically, the uncertainty in position-momentum is analyzed, with specific focus on characterizing regions of minimum uncertainty states, regions where the uncertainties are bounded from above, and where they grow unbound.

Kornbluth, Mordechai; Zypman, Fredy [Physics Department, Yeshiva University, 500 W 185th Street, New York, New York 10033 (United States)] [Physics Department, Yeshiva University, 500 W 185th Street, New York, New York 10033 (United States)

2013-01-15T23:59:59.000Z

331

On the coherent behavior of pancreatic beta cell clusters  

E-Print Network [OSTI]

Beta cells in pancreas represent an example of coupled biological oscillators which via communication pathways, are able to synchronize their electrical activity, giving rise to pulsatile insulin release. In this work we numerically analyze scale free self-similarity features of membrane voltage signal power density spectrum, through a stochastic dynamical model for beta cells in the islets of Langerhans fine tuned on mouse experimental data. Adopting the algebraic approach of coherent state formalism, we show how coherent molecular domains can arise from proper functional conditions leading to a parallelism with "phase transition" phenomena of field theory.

Alessandro Loppini; Antonio Capolupo; Christian Cherubini; Alessio Gizzi; Marta Bertolaso; Simonetta Filippi; Giuseppe Vitiello

2014-07-29T23:59:59.000Z

332

Dihedral symmetry of periodic chain: quantization and coherent states  

E-Print Network [OSTI]

Our previous work on quantum kinematics and coherent states over finite configuration spaces is extended: the configuration space is, as before, the cyclic group $Z_{n}$ of arbitrary order n=2,3,..., but as its symmetry group a larger group -- the non-Abelian dihedral group $D_{n}$ -- is taken. The corresponding group related coherent states are constructed and their overcompleteness proved. Our approach based on geometric symmetry can be used as a kinematic framework for matrix methods in quantum chemistry of ring molecules.

Luft, P; Tolar, J

2007-01-01T23:59:59.000Z

333

Coherent-feedback quantum control with a dynamic compensator  

E-Print Network [OSTI]

I present an experimental realization of a coherent-feedback control system that was recently proposed for testing basic principles of linear quantum stochastic control theory [M. R. James, H. I. Nurdin and I. R. Petersen, to appear in IEEE Transactions on Automatic Control (2008), arXiv:quant-ph/0703150v2]. For a dynamical plant consisting of an optical ring-resonator, I demonstrate ~ 7 dB broadband disturbance rejection of injected laser signals via all-optical feedback with a tailored dynamic compensator. Comparison of the results with a transfer function model pinpoints critical parameters that determine the coherent-feedback control system's performance.

Hideo Mabuchi

2008-03-13T23:59:59.000Z

334

Coherent Oscillations in an Exciton-Polariton Josephson Junction  

SciTech Connect (OSTI)

We report on the observation of spontaneous coherent oscillations in a microcavity polariton bosonic Josephson junction. Condensation of exciton polaritons here takes place under incoherent excitation in a double potential well naturally formed in the disorder. Coherent oscillations set on at an excitation power well above the condensation threshold. The time resolved population and phase dynamics reveal the analogy with the ac Josephson effect. A theoretical two-mode model describes the observed effects, explaining how the different realizations of the pulsed experiment can be in phase.

Lagoudakis, K. G.; Pietka, B.; Deveaud-Pledran, B. [ICMP, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Wouters, M. [ITP, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Andre, R. [Institut Neel, CNRS, Grenoble (France)

2010-09-17T23:59:59.000Z

335

ON THE SUITABILITY OF LONGITUDINAL PROFILE MEASUREMENTS USING COHERENT SMITH-PURCELL RADIATION  

E-Print Network [OSTI]

Kittelmann, C. Thomas, ESS, Lund, Sweden Abstract The use of Smith-Purcell radiation to measure electrons power, it is mandatory to understand the beam dynamics and to determine the beam size and profile with precision. In high power proton Linacs, such under- standing would allow a full characterization of the beam

Boyer, Edmond

336

Endoscopic optical coherence tomography for clinical studies in the gastrointestinal tract  

E-Print Network [OSTI]

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. ...

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

2013-01-01T23:59:59.000Z

337

Optical measurement of neural action potentials using low coherence heterodyne interferometry  

E-Print Network [OSTI]

We present a novel non-invasive optical method for detection of neural action potentials using low coherence interferometry. The dual beam heterodyne interferometer (DBHI) is a modified Michelson with a low coherence source ...

Chu, Mark Changhao, 1978-

2004-01-01T23:59:59.000Z

338

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

E-Print Network [OSTI]

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...

Wang, Xi

2012-07-16T23:59:59.000Z

339

Coherence of resonant-tunneling transport in terahertz quantum-cascade lasers  

E-Print Network [OSTI]

We develop simple density-matrix models to describe the role of coherence in resonant-tunneling (RT) transport of quantum-cascade lasers (QCLs). Specifically, we investigate the effects of coherent coupling between the ...

Kumar, Sushil

340

Chirality dependence of coherent phonon amplitudes in single-wall carbon nanotubes  

E-Print Network [OSTI]

We simulate the ultrafast dynamics of laser-induced coherent phonons in single-wall carbon nanotubes (SWNTs). In particular, we examine the coherent phonon amplitude of the radial breathing mode (RBM) as a function of ...

Dresselhaus, Mildred

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Limitations for detecting small-scale faults using the coherency analysis of seismic data  

E-Print Network [OSTI]

Coherency analyzes the trace to trace amplitude similarities recorded by seismic waves. Coherency algorithms have been used to identify the structural or stratigraphic features of an area but the limitations for detecting small-scale features...

Barnett, David Benjamin

2006-08-16T23:59:59.000Z

342

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]

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.

Orlando Tapia

2014-07-14T23:59:59.000Z

343

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

SciTech Connect (OSTI)

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

Jacobsen, Chris

2014-12-07T23:59:59.000Z

344

Towards a more coherent oil policy in Russia? S. Boussena,  

E-Print Network [OSTI]

Towards a more coherent oil policy in Russia? S. Boussena, Professor, University of Grenoble II of Russia on the world oil scene. The first is the development of its oil production (over 9 Mb/d in 2004. Will Russia be a key variable in world energy balances? Could Russia ­ as some suggest and even desire

Paris-Sud XI, Université de

345

Quantum coherent switch utilizing commensurate nanoelectrode and charge density periodicities  

DOE Patents [OSTI]

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.

Harrison, Neil (Santa Fe, NM); Singleton, John (Los Alamos, NM); Migliori, Albert (Santa Fe, NM)

2008-08-05T23:59:59.000Z

346

USING OPTICAL COHERENCE TOMOGRAPHY TO EXAMINE THE SUBSURFACE MORPHOLOGY OF  

E-Print Network [OSTI]

: (1) a homogeneous glassy phase; (2) a liquid­liquid phase separated state; and (3) a crystallizedUSING OPTICAL COHERENCE TOMOGRAPHY TO EXAMINE THE SUBSURFACE MORPHOLOGY OF CHINESE GLAZES M of their glazes. The images revealed unique phase assemblage modes in different samples. The results suggest

Barton, Jennifer K.

347

Monostatic Coherent Radar Sea Clutter Doppler Analysis Matthew Ritchie  

E-Print Network [OSTI]

measurements are potentially ambiguous. Both the PRF and radio frequency used by the radar system are agile to define what PFA the radar system will experience for a given threshold level. This defines the radarsMonostatic Coherent Radar Sea Clutter Doppler Analysis Matthew Ritchie University College London

Haddadi, Hamed

348

Exact Coherent Structures in Pipe Flow: Travelling Wave Solutions  

E-Print Network [OSTI]

1 Exact Coherent Structures in Pipe Flow: Travelling Wave Solutions H. Wedin & R.R. Kerswell pipe. They consist of three well-defined flow features - streamwise rolls and streaks which dominate symmetry they possess about the pipe axis with m = 1, 2, 3, 4, 5 and 6 solutions identified. All are born

Burton, Geoffrey R.

349

Image analysis for the identification of coherent structures in plasma  

E-Print Network [OSTI]

-based - and empirically evaluate their performance on four sample sequences. Our preliminary results indicate that while., Livermore, USA ABSTRACT Turbulence at the edge of the plasma in a nuclear fusion reactor can cause loss in experimental reactors. These images have indicated the presence of "coherent" structures which "retain

Kamath, Chandrika

350

Tuning a short coherence length Josephson junction through a  

E-Print Network [OSTI]

Tuning a short coherence length Josephson junction through a metal-insulator transition J. K University, Josephson Junction talk, 2001 #12;Josephson Tunnel Junctions · A Superconductor maintaining nonhysteretic behavior. J. K. Freericks, Georgetown University, Josephson Junction talk, 2001 S N

Freericks, Jim

351

Adaptive coherent interferometric imaging for sensor networks Gregoire Derveauxa)  

E-Print Network [OSTI]

with distributed sensor networks is presented. The sensors record the impulse response of the unknown background imaging when the background is known is considered in Ref.8. The sensors record an approximate impulseAdaptive coherent interferometric imaging for sensor networks Gr´egoire Derveauxa) INRIA Domaine de

Papanicolaou, George C.

352

Adaptive optics enhanced simultaneous en-face optical coherence tomography  

E-Print Network [OSTI]

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

Dainty, Chris

353

Optimal energy-preserving conversions of quantum coherence  

E-Print Network [OSTI]

Given two coherent superpositions of energy eigenstates, we search for the best evolution that converts one superposition into the other without exchanging energy with the surrounding environment. We consider both deterministic and probabilistic evolutions, which can be obtained by measuring the environment and postselecting a subset of the outcomes. For every fixed value of the postselection probability, we characterize the process that maximizes the fidelity of the output state with the target, showing that the optimal measurement can be chosen without loss of generality to be binary and pure. We then construct a recursive protocol, which allows one to increase the success probability while reaching maximum fidelity at each step of the iteration. In turn, the recursive protocol is used to generate efficient approximations of the optimal fidelity-probability tradeoff, via a technique dubbed coherent coarse-graining. Such a technique can be applied not only to energy-preserving conversions, but also to general conversions of pure states under linear constraints. The recursive protocol and its coherent coarse-graining are illustrated in a series of applications to phase estimation, quantum cloning, coherent state amplification, and ancilla-driven computation.

Yuxiang Yang; Giulio Chiribella

2015-02-01T23:59:59.000Z

354

A Study on the Coherent Atomic Effects and Their Applications  

E-Print Network [OSTI]

OF CONTENTS CHAPTER Page I INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . 1 A. Semiclassical theory . . . . . . . . . . . . . . . . . . . . . . 3 B. Coherent population trapping . . . . . . . . . . . . . . . . 5 C. Electromagnetically induced...-atom scheme . . . . . . . . . . . . . . . . . . . . 64 2. Zeeman-level scheme . . . . . . . . . . . . . . . . . . . 66 3. Probability and information analysis . . . . . . . . . . 68 C. Click-allowed reversal . . . . . . . . . . . . . . . . . . . . . 69 D...

Sun, Qingqing

2010-07-14T23:59:59.000Z

355

Optimal energy-preserving conversions of quantum coherence  

E-Print Network [OSTI]

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.

Yuxiang Yang; Giulio Chiribella

2015-03-05T23:59:59.000Z

356

Freie Universitt Berlin Transient reflectivity and coherent phonon  

E-Print Network [OSTI]

Freie Universität Berlin Transient reflectivity and coherent phonon excitation: An ultrafast probe-Hubbard? . . . . . . 35 1.3.3 The photoinduced phase transition . . . . . . . . . . . . . . . . . . . 36 I #12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2.1.1 Generation of ultrashort laser pulses: the mode-locked Ti:Sapphire oscillator

Wolf, Martin

357

Phased laser array with tailored spectral and coherence properties  

DOE Patents [OSTI]

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.

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

2014-05-20T23:59:59.000Z

358

Coherence Progress: A Measure of Interestingness Based on Fixed Compressors  

E-Print Network [OSTI]

has been investigated in various ways in the literature, ranging from early work by Wundt [9] (seeCoherence Progress: A Measure of Interestingness Based on Fixed Compressors Tom Schaul, Leo Pape in observations to store them in a compact form, called a compressor. The search for interesting patterns can

Schmidhuber, Juergen

359

Special Section Guest Editorial Coherent Raman Imaging Techniques and Biomedical  

E-Print Network [OSTI]

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

Potma, Eric Olaf

360

On blind searches for noise dominated signals: a loosely coherent approach  

E-Print Network [OSTI]

We introduce a "loosely coherent" method for detection of continuous gravitational waves that bridges the gap between semi-coherent and purely coherent methods. Explicit control over accepted families of signals is used to increase sensitivity of power-based statistic while avoiding the high computational costs of conventional matched filters. Several examples as well as a prototype implementation are discussed.

Vladimir Dergachev

2010-08-23T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Economic Impact Reporting Framework  

E-Print Network [OSTI]

Economic Impact Reporting Framework 2007/08 November 2008 #12;#12;Economic Impact Reporting Framework 2007/08 #12;STFC Economic Impact Reporting Framework 2007/08 Contents: Introduction..............................................................................................................................................2 1: Overall Economic Impacts

362

Economic Impact Reporting Framework  

E-Print Network [OSTI]

Economic Impact Reporting Framework 2008/09 #12;#12;Economic Impact Reporting Framework 2008/09 #12;STFC Economic Impact Reporting Framework 2008/09 Contents: Introduction..............................................................................................................................................2 1: Overall Economic Impacts

363

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...

364

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]

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

Danon, Yaron

365

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]

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

Danon, Yaron

366

Theory of femtosecond coherent anti-Stokes Raman backscattering enhanced by quantum coherence for standoff detection of bacterial spores  

E-Print Network [OSTI]

large backscattered signal in the far field, using typical parameters of an anthrax spore with maximally prepared vibrational coherence. Using train pulses of 1 kHz of repetition rate each with energy of 10 mJ, we estimate that about 10(7) photons can...

Ooi, C. H. Raymond; Beadie, G.; Kattawar, George W.; Reintjes, J. F.; Rostovtsev, Y.; Zubairy, M. Suhail; Scully, Marlan O.

2005-01-01T23:59:59.000Z

367

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest RegionatSearchScheduled System OutagesNews PressThemes Scientific Impact

368

Klystron-linac combination  

DOE Patents [OSTI]

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.

Stein, W.E.

1980-04-24T23:59:59.000Z

369

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region serviceMission Statement Titan TargetInJupiterUser Los

370

Qubit architecture with high coherence and fast tunable coupling  

E-Print Network [OSTI]

We introduce a superconducting qubit architecture that combines high-coherence qubits and tunable qubit-qubit coupling. With the ability to set the coupling to zero, we demonstrate that this architecture is protected from the frequency crowding problems that arise from fixed coupling. More importantly, the coupling can be tuned dynamically with nanosecond resolution, making this architecture a versatile platform with applications ranging from quantum logic gates to quantum simulation. We illustrate the advantages of dynamic coupling by implementing a novel adiabatic controlled-Z gate, at a speed approaching that of single-qubit gates. Integrating coherence and scalable control, our "gmon" architecture is a promising path towards large-scale quantum computation and simulation.

Yu Chen; C. Neill; P. Roushan; N. Leung; M. Fang; R. Barends; J. Kelly; B. Campbell; Z. Chen; B. Chiaro; A. Dunsworth; E. Jeffrey; A. Megrant; J. Y. Mutus; P. J. J. O'Malley; C. M. Quintana; D. Sank; A. Vainsencher; J. Wenner; T. C. White; Michael R. Geller; A. N. Cleland; John M. Martinis

2014-02-28T23:59:59.000Z

371

Momentum dissipation and effective theories of coherent and incoherent transport  

E-Print Network [OSTI]

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.

Richard A. Davison; Blaise Goutéraux

2015-01-21T23:59:59.000Z

372

High-Temperature Quantum Coherence from Dissipative Environments  

E-Print Network [OSTI]

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.

George E. Cragg

2014-11-14T23:59:59.000Z

373

Apparatus for generating coherent infrared energy of selected wavelength  

DOE Patents [OSTI]

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).

Stevens, Charles G. (Danville, CA)

1985-01-01T23:59:59.000Z

374

Folded Compact Range Development and Coherent Change Detection Measurement Project  

SciTech Connect (OSTI)

A novel, folded compact range configuration has been developed at the Sandia National Laboratories compact range antenna and radar cross section measurement facility, operated by the Radar/Antenna Department 2343, as a means of performing indoor, environmentally-controlled, far-field simulations of synthetic aperture radar (SAR) coherent change detection (CCD) measurements. This report describes the development of the folded compact range configuration, as well as the initial set of coherent change detection measurements made with the system. These measurements have been highly successful, and have demonstrated the viability of the folded compact range concept in simulating SAR CCD measurements. It is felt that follow-on measurements have the potential of contributing significantly to the body of knowledge available to the scientific community involved in CCD image generation and processing, and that this tool will be a significant aid in the research and development of change detection methodologies.

Sorensen, K.W.

1995-03-01T23:59:59.000Z

375

Emission of coherent THz-radiation from superconductors.  

SciTech Connect (OSTI)

Compact solid-state sources of terahertz (THz) radiation are being sought for sensing, imaging, and spectroscopy applications across the physical and biological sciences. We demonstrate that coherent continuous-wave THz radiation of sizable power can be extracted from intrinsic Josephson junctions in the layered high-temperature superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}. In analogy to a laser cavity, the excitation of an electromagnetic cavity resonance inside the sample generates a macroscopic coherent state in which a large number of junctions are synchronized to oscillate in phase. The emission power is found to increase as the square of the number of junctions reaching values of 0.5 microwatt at frequencies up to 0.85 THz, and persists up to 50 kelvin. These results should stimulate the development of superconducting compact sources of THz radiation.

Ozyuzer, L.; Koshelev, A. E.; Kurter, C.; Gopalsami, N.; Li, Q.; Tachiki, M.; Kadowaki, K.; Yamamoto, T.; Minami, H.; Yamaguchi, H.; Tachiki, T.; Gray, K. E.; Kwok, W.- K.; Welp, U.; Izmir Inst. Tech.; Illinois Inst. Tech.; Univ. Tokyo; Univ. Tsukuba; Nat. Defence Academy

2007-11-23T23:59:59.000Z

376

Observation of detection-dependent multi-photon coherence times  

E-Print Network [OSTI]

The coherence time constitutes one of the most critical parameters that determines whether or not interference is observed in an experiment. For photons, it is traditionally determined by the effective spectral bandwidth of the photon. Here we report on multi-photon interference experiments in which the multi-photon coherence time, defined by the width of the interference signal, depends on the number of interfering photons and on the measurement scheme chosen to detect the particles. A theoretical analysis reveals that all multi-photon interference with more than two particles features this dependence, which can be attributed to higher-order effects in the mutual indistinguishability of the particles. As a striking consequence, a single, well-defined many-particle quantum state can exhibit qualitatively different degrees of interference, depending on the chosen observable. Therefore, optimal sensitivity in many-particle quantum interferometry can only be achieved by choosing a suitable detection scheme.

Young-Sik Ra; Malte C. Tichy; Hyang-Tag Lim; Osung Kwon; Florian Mintert; Andreas Buchleitner; Yoon-Ho Kim

2015-01-12T23:59:59.000Z

377

Long-range coherent energy transport in Photosystem II  

E-Print Network [OSTI]

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 ...

Roden, Jan J J; Whaley, K Birgitta

2015-01-01T23:59:59.000Z

378

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]

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...

Lee, Suk; Chang, Kyung Hwan; Shim, Jang Bo; Kim, Kwang Hyeon; Lee, Nam Kwon; Park, Young Je; Kim, Chul Yong; Cho, Sam Ju; Lee, Sang Hoon; Min, Chul Kee; Kim, Woo Chul; Cho, Kwang Hwan; Huh, Hyun Do; Lim, Sangwook; Shin, Dongho

2015-01-01T23:59:59.000Z

379

On Quantum Coherence Effects in Photo and Solar Cells  

E-Print Network [OSTI]

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).

Kimberly Chapin; Konstantin Dorfman; Anatoly Svidzinsky; Marlan Scully

2011-02-01T23:59:59.000Z

380

On the Construction of Generalized Grassmann Coherent States  

E-Print Network [OSTI]

A generalized definition of a deformation of the fermionic oscillator (k-fermionic oscillators) is proposed. Two prescriptions for the construction of generalized Grassmann coherent states for this kind of oscillators are derived. The two prescriptions differs in the nature of the generalized Grassmann variables used. While we use Majid's definition for such variables in the first case, Kerner's definition is used in the second one.

M. El Baz

2005-11-07T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Coherent seeding of self-modulated plasma wakefield accelerators  

SciTech Connect (OSTI)

The growth of the beam self-modulation and hosing instabilities initiated by a seed wakefield is examined. Although the growth rates for the self-modulation and hosing instabilities are comparable, it is shown that an externally excited wakefield can be effective in selectively seeding the beam radial self-modulation, enabling the beam to fully modulate before strong beam hosing develops. Methods for coherent seeding are discussed.

Schroeder, C. B.; Benedetti, C.; Esarey, E.; Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Grüner, F. J. [Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)] [Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)

2013-05-15T23:59:59.000Z

382

C-III flow measurements with a coherence imaging spectrometer  

SciTech Connect (OSTI)

This work describes a coherence imaging spectrometer capable of making spatially resolved CIII flow measurements in the DIII-D lower divertor. The spectrometer exploits a periscope view of the plasma to produce line-of-sight averaged velocity measurements of CIII. From these chord averaged flow measurements, a 2D poloidal cross section of the CIII flow is tomographically reconstructed. Details of the diagnostic setup, acquired data, and data analysis will be presented, along with prospects for future applications.

Weber, T. R.; Allen, S. L. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Howard, J. [Australian National University, Canberra, ACT 0200 (Australia)

2012-10-15T23:59:59.000Z

383

CONTROL OF COHERENT STRUCTURE IN COAXIAL SWIRLING TURBULENT JETS  

E-Print Network [OSTI]

.............................................................. 193 xvi NOMENCLATURE Symbol Description Unit D Jet diameter, Defined in Figure 5.1 m D h Hydraulic jet diameter m f Excitation frequency s -1 G Degree of swirl, Defined... stronger effect than the pilot jet itself, leading to an almost entire removal of coherent structures. 2.2. Flow Instability Swirl is naturally presented in the exhaust from a turbine or an axial flow pump, and may be deliberately generated...

Lee, Wonjoong

2008-01-01T23:59:59.000Z

384

Ultrarelativistic laser systems based on coherent beam combining  

SciTech Connect (OSTI)

Conceptual design for femtosecond laser system of exawatt class, based on multi-channel amplifier and coherent field combining of petawatt amplifier channels with phase-frequency controlled radiation by optical clock are discussed. The scheme of start petawatt level few-cycle laser system with stable phase-frequency parameters determinated by the accuracy of the optical standard based on parametric amplification in big-size LBO crystals pumped by picosecond pulses is analyzed.

Bagayev, S. N.; Trunov, V. I.; Pestryakov, E. V.; Frolov, S. A.; Leschenko, V. E.; Kirpichnikov, A. V.; Kokh, A. E.; Petrov, V. V.; Vasiliev, V. A. [Institute of Laser Physics SB RAS, Ac. Lavrentyev's prosp., 13/3, Novosibirsk (Russian Federation); Institute of Geology and Mineralogy SB RAS, Ac. Koptug's prosp., 3, Novosibirsk (Russian Federation); Institute of Laser Physics SB RAS, Ac. Lavrentyev's prosp., 13/3, Novosibirsk (Russian Federation)

2012-07-11T23:59:59.000Z

385

Coherent properties of single rare-earth spin qubits  

E-Print Network [OSTI]

Rare-earth-doped crystals are excellent hardware for quantum storage of optical information. Additional functionality of these materials is added by their waveguiding properties allowing for on-chip photonic networks. However, detection and coherent properties of rare-earth single-spin qubits have not been demonstrated so far. Here, we present experimental results on high-fidelity optical initialization, effcient coherent manipulation, and optical readout of a single electron spin of Ce$^{3+}$ ion in a YAG crystal. Under dynamic decoupling, spin coherence lifetime reaches $T_2$=2 ms and is almost limited by the measured spin-lattice relaxation time $T_1$=3.8 ms. Strong hyperfine coupling to aluminium nuclear spins suggests that cerium electron spins can be exploited as an interface between photons and long-lived nuclear spin memory. Combined with high brightness of Ce$^{3+}$ emission and a possibility of creating photonic circuits out of the host material, this makes cerium spins an interesting option for integrated quantum photonics.

P. Siyushev; K. Xia; R. Reuter; M. Jamali; N. Zhao; N. Yang; C. Duan; N. Kukharchyk; A. D. Wieck; R. Kolesov; J. Wrachtrup

2014-05-20T23:59:59.000Z

386

Quantum fluctations of coherent light in nonlinear media  

E-Print Network [OSTI]

The interaction of coherent light with a nonlinear medium is modeled here by a general quantum anharmonic oscillator. The model is not exactly solvable in a closed analytical form. But we need operator solutions of the equations of motion corresponding to these models in order to study the quantum fluctuations of coherent light in nonlinear media. In the present work we derive approximate operator solutions. From these solutions we observe that there exists an apparent discrepancy between the solutions obtained by different techniques. We compare different solutions and conclude that all correct solutions are equivalent and the apparent discrepancy is due to the use of different ordering of the operators. We use these solutions to investigate the possibilities of observing different optical phenomena in a nonlinear dielectric medium. To be precise, we have studied quantum phase fluctuations of coherent light in a third order inversion symmetric nonlinear medium. Fluctuations in phase space quadrature for the same system are studied and the possibility of generating squeezed state is reported. Fluctuations in photon number are studied and the nonclassical phenomenon of antibunching is predicted. We have generalized the results obtained for third order nonlinear medium and have studied the interaction of an intense laser beam with a general (m-1)-th order nonlinear medium. Aharanov Anandan nonadiabatic geometric phase is also discussed in the context of (m-1)-th order nonlinear medium.

Anirban Pathak

2002-07-05T23:59:59.000Z

387

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

SciTech Connect (OSTI)

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.

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)

2011-12-15T23:59:59.000Z

388

Privacy Impact Assessment  

Energy Savers [EERE]

PRIVACY IMPACT ASSESSMENT: ORG NAME - SYSTEM NAME PIA Template Version 3 - May, 2009 1 Department of Energy Privacy Impact Assessment (PIA) Guidance is provided in the template....

389

The SU(1, 1) Perelomov number coherent states and the non-degenerate parametric amplifier  

SciTech Connect (OSTI)

We construct the Perelomov number coherent states for an arbitrary su(1, 1) group operation and study some of their properties. We introduce three operators which act on Perelomov number coherent states and close the su(1, 1) Lie algebra. By using the tilting transformation we apply our results to obtain the energy spectrum and eigenfunctions of the non-degenerate parametric amplifier. We show that these eigenfunctions are the Perelomov number coherent states of the two-dimensional harmonic oscillator.

Ojeda-Guillén, D., E-mail: dojedag@ipn.mx; Granados, V. D. [Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Ed. 9, Unidad Profesional Adolfo López Mateos, C.P. 07738 México D. F. (Mexico)] [Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Ed. 9, Unidad Profesional Adolfo López Mateos, C.P. 07738 México D. F. (Mexico); Mota, R. D. [Escuela Superior de Ingeniería Mecánica y Eléctrica, Unidad Culhuacán, Instituto Politécnico Nacional, Av. Santa Ana No. 1000, Col. San Francisco Culhuacán, Delegación Coyoacán, C.P. 04430, México D. F. (Mexico)] [Escuela Superior de Ingeniería Mecánica y Eléctrica, Unidad Culhuacán, Instituto Politécnico Nacional, Av. Santa Ana No. 1000, Col. San Francisco Culhuacán, Delegación Coyoacán, C.P. 04430, México D. F. (Mexico)

2014-04-15T23:59:59.000Z

390

Crystal coherence length effects on the infrared optical response of MgO thin films.  

SciTech Connect (OSTI)

The role of crystal coherence length on the infrared optical response of MgO thin films was investigated with regard to Reststrahlen band photon-phonon coupling. Preferentially (001)-oriented sputtered and evaporated ion-beam assisted deposited thin films were prepared on silicon and annealed to vary film microstructure. Film crystalline coherence was characterized by x-ray diffraction line broadening and transmission electron microscopy. The infrared dielectric response revealed a strong dependence of dielectric resonance magnitude on crystalline coherence. Shifts to lower transverse optical phonon frequencies were observed with increased crystalline coherence. Increased optical phonon damping is attributed to increasing granularity and intergrain misorientation.

Boreman, Glenn D. (University of Central Florida, Orlando, FL); Kotula, Paul Gabriel; Rodriguez, Mark Andrew; Shelton, David J. (University of Central Florida, Orlando, FL); Carroll, James F., III; Sinclair, Michael B.; Ihlefeld, Jon F.; Ginn, James Cleveland, III; Clem, Paul Gilbert; Matias, Vladimir (Los Alamos National Laboratory, Los Alamos, NM)

2010-07-01T23:59:59.000Z

391

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

E-Print Network [OSTI]

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

Scully, Marlan O

2010-01-01T23:59:59.000Z

392

E-Print Network 3.0 - asymmetric coherent transmission Sample...  

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

in the array. In a "coherent" metamaterial ... Source: Zheludev, Nikolay - Optoelectronics Research Centre & School of Physics and Astronomy, University of Southampton...

393

Coherent Resonances Observed in the Dissociative Electron Attachments to Carbon Monoxide  

E-Print Network [OSTI]

Succeeding our previous finding about coherent interference of the resonant states of CO^- formed by the low-energy electron attachment [Phys. Rev. A 88, 012708 (2013)], here we provide more evidences of the coherent interference, in particular, we find the state configuration change in the interference with the increase of electron attachment energy by measuring the completely backward distributions of the O^- fragment ion of the temporary CO^- in an energy range 11.3-12.6 eV. Therefore, different pure states, namely, coherent resonances, can be formed when the close-lying resonant states are coherently superposed by a broad-band electron pulse.

Wang, Xu-Dong; Luo, Yi; Tian, Shan Xi

2015-01-01T23:59:59.000Z

394

E-Print Network 3.0 - adiabatic coherent electron Sample Search...  

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

of Technology Collection: Physics 12 Adiabatic Transport of Cooper Pairs in Josephson Junction Circuits Summary: this technique for "non- invasive" measurements of coherent...

395

Loss of coherence in dynamical networks: spatial chaos and chimera states  

E-Print Network [OSTI]

We discuss the breakdown of spatial coherence in networks of coupled oscillators with nonlocal interaction. By systematically analyzing the dependence of the spatio-temporal dynamics on the range and strength of coupling, we uncover a dynamical bifurcation scenario for the coherence-incoherence transition which starts with the appearance of narrow layers of incoherence occupying eventually the whole space. Our findings for coupled chaotic and periodic maps as well as for time-continuous R\\"ossler systems reveal that intermediate, partially coherent states represent characteristic spatio-temporal patterns at the transition from coherence to incoherence.

Iryna Omelchenko; Yuri Maistrenko; Philipp Hövel; Eckehard Schöll

2011-05-19T23:59:59.000Z

396

E-Print Network 3.0 - angle-resolved optical coherence Sample...  

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

Angle ... Source: Roma "La Sapienza", Universit di - Dipartimento di Fisica, Quantum Optics Group Collection: Physics 2 Ultrafast coherent control of electric currents at metal...

397

Coherent Multiresolution Isosurface Ray Tracing Aaron Knoll, Charles Hansen, and Ingo Wald  

E-Print Network [OSTI]

Scientific Computing and Imaging Institute University of Utah Salt Lake City, Utah 84112 Email: {knolla1 Coherent Multiresolution Isosurface Ray Tracing Aaron Knoll, Charles Hansen, and Ingo Wald

Wald, Ingo

398

E-Print Network 3.0 - atomic coherent control Sample Search Results  

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

Spin Self... -Rephasing and Very Long Coherence Times in a Trapped Atomic Ensemble C. Deutsch, F. Ramirez-Martinez, C. Lacrote, F... . 105, 020401 (2010) - Published July 6,...

399

Effect of optical inhomogeneities on the spatial coherence of unstable-cavity laser radiation  

SciTech Connect (OSTI)

The effect of model optical inhomogeneities of various types (static and dynamic, small-scale and large-scale) on the spatial coherence of unstable-cavity laser radiation is studied. Quantitative relations are established between the amount of inhomogeneities introduced and spatial coherence of the laser radiation that allow us to formulate requirements to the optical uniformity of the active medium of the laser with a given coherence of the lasing radiation, and predict the value and nature of coherence of the unstable-cavity laser radiation for known values of optical inhomogeneities of the active medium.

Danilova, L.A.; Staselko, D.I.; Strigun, V.L.

1986-12-01T23:59:59.000Z

400

Chaoticity and Coherence in Bose-Eistein Condensation and Correlations  

E-Print Network [OSTI]

We review the properties of chaoticity and coherence in Bose-Einstein condensation and correlations, for a dense boson system in its mean-field represented approximately by a harmonic oscillator potential. The order parameter and the nature of the phase transition from the chaotic to the condensate states are studied for different fixed numbers of bosons. The two-particle correlation function in momentum space is calculated to investigate how the Bose-Einstein correlation depends on the degree of condensation and other momentum variables. We generalize the Bose-Einstein correlation analysis to three-particle correlations to show its dependence on the degree of condensation.

Wong, Cheuk-Yin; Liu, Jie; Ru, Peng

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Chaoticity and Coherence in Bose-Einstein Condensation and Correlations  

E-Print Network [OSTI]

We review the properties of chaoticity and coherence in Bose-Einstein condensation and correlations, for a dense boson system in its mean-field represented approximately by a harmonic oscillator potential. The order parameter and the nature of the phase transition from the chaotic to the condensate states are studied for different fixed numbers of bosons. The two-particle correlation function in momentum space is calculated to investigate how the Bose-Einstein correlation depends on the degree of condensation and other momentum variables. We generalize the Bose-Einstein correlation analysis to three-particle correlations to show its dependence on the degree of condensation.

Cheuk-Yin Wong; Wei-Ning Zhang; Jie Liu; Peng Ru

2015-01-23T23:59:59.000Z

402

Efficient Energy Transport in Photosynthesis: Roles of Coherence and Entanglement  

SciTech Connect (OSTI)

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.

Patel, Apoorva D. [Centre for High Energy Physics and Supercomputer Education and Research Centre, Indian Institute of Science, Bangalore 560012 (India)

2011-09-23T23:59:59.000Z

403

Precision spectral manipulation: a demonstration using a coherent optical memory  

E-Print Network [OSTI]

The ability to coherently spectrally manipulate quantum information has the potential to improve qubit rates across quantum channels and find applications in optical quantum computing. In this paper we present experiments that use a multi-element solenoid combined with the three-level gradient echo memory scheme to perform precision spectral manipulation of optical pulses. These operations include bandwidth and frequency manipulation, spectral filtering of separate frequency components, as well as time-delayed interference between pulses with both the same, and different, frequencies. These operations have potential uses in quantum information applications.

Sparkes, B M; Hosseini, M; Higginbottom, D; Campbell, G; Lam, P K; Buchler, B C

2012-01-01T23:59:59.000Z

404

LCS Tool : A Computational Platform for Lagrangian Coherent Structures  

E-Print Network [OSTI]

We give an algorithmic introduction to Lagrangian coherent structures (LCSs) using a newly developed computational engine, LCS Tool. LCSs are most repelling, attracting and shearing material lines that form the centerpieces of observed tracer patterns in two-dimensional unsteady dynamical systems. LCS Tool implements the latest geodesic theory of LCSs for two-dimensional flows, uncovering key transport barriers in unsteady flow velocity data as explicit solutions of differential equations. After a review of the underlying theory, we explain the steps and numerical methods used by LCS Tool, and illustrate its capabilities on three unsteady fluid flow examples.

K. Onu; F. Huhn; G. Haller

2014-06-13T23:59:59.000Z

405

Efficient Energy Transport in Photosynthesis: Roles of Coherence and Entanglement  

E-Print Network [OSTI]

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.

Apoorva D. Patel

2011-04-07T23:59:59.000Z

406

Efficient Energy Transport in Photosynthesis: Roles of Coherence and Entanglement  

E-Print Network [OSTI]

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.

Patel, Apoorva D

2011-01-01T23:59:59.000Z

407

Coherent electron cooling proof of principle instrumentation design  

SciTech Connect (OSTI)

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.

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

2012-04-15T23:59:59.000Z

408

Coherent excitation of a strongly coupled quantum dot - cavity system  

E-Print Network [OSTI]

We have studied the coherent excitation of a strongly coupled QD/photonic crystal cavity system. Time-resolved reflectivity measurements show the vacuum Rabi oscillation of the dot in the cavity. Next, we considered the resonant driving of a cavity-detuned dot, which efficiently populates the cavity mode. This cavity-controlled read-out channel allows high-resolution single quantum dot spectroscopy. Autocorrelation measurements on the cavity mode show antibunching and suggest the use of the resonantly driven QD/cavity system as an on-demand source of single photons with potentially near-unity indistinguishability.

Dirk Englund; Arka Majumdar; Andrei Faraon; Mitsuru Toishi; Nick Stoltz; Pierre Petroff; Jelena Vuckovic

2009-02-19T23:59:59.000Z

409

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 - September 2006Photovoltaic TheoryPlant 242-ZPolaron Behavior inPolaron Coherence

410

Original Impact Calculations  

Broader source: Energy.gov [DOE]

Original Impact Calculations, from the Tool Kit Framework: Small Town University Energy Program (STEP).

411

Effects of e-beam parameters on coherent electron cooling  

SciTech Connect (OSTI)

Coherent Electron Cooling (CeC) requires detailed control of the phase between the hadron an the FEL-amplified wave packet. This phase depends on local electron beam parameters such as the energy spread and the peak current. In this paper, we examine the effects of local density variations on the cooling rates for CeC. Coherent Electron Cooling (CeC) [1] is a new concept in intense, high energy hadron beamcooling, in which the Debye screened charge perturbation calculated in [2] is used to seed a high-gain free electron laser (FEL). Using delays to give the perturbing hadron an energy-dependent longitudinal displacement relative to its frequencymodulated charge perturbation, the hadron receives an energy-dependent kick which reduces its energy variation from the design energy. The equations of motion in [1] assume that the electron bunch is the same physical size as the hadron bunch, and has a homogeneous charge density across the entire bunch. In practice, the electron bunches will be much shorter than the hadron bunch, and this local spacial inhomogeneity in the charge distribution will alter the gain length of the FEL, resulting in both a change in the amplification of the initial signal and a phase shift. In this paper we consider these inhomogeneity effects, determining cooling equations for bunched beam CeC consistent with these effects and determining thresholds for the cooling parameters.

Webb, S.D.; Litvinenko, V.N.; Wang, G.

2011-03-28T23:59:59.000Z

412

Atomic Resolution Coherent Diffractive Imaging and Ultrafast Science  

SciTech Connect (OSTI)

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.

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

2011-01-12T23:59:59.000Z

413

Universal Blind Quantum Computing with Weak Coherent Pulses  

E-Print Network [OSTI]

The recently proposed Universal Blind Quantum Computation (UBQC) protocol allows a client to perform an arbitrary quantum computation on a remote server such that perfect privacy is guaranteed if the client is capable of producing random separable single qubit states. While from a theoretical point of view, this arguably constitutes the lowest possible quantum requirement, from a pragmatic point of view, generation of random single qubits which can be sent along long distances without loss is quite challenging and can never be achieved perfectly. In analogy to the concept of approximate security developed for other cryptographic protocols, we introduce here the concept of approximate blindness for UBQC, allowing us to characterize the robustness of the protocol to possible imperfections. Following this, we present a remote blind single qubit preparation protocol, by which a client with access to realistic quantum devices (such as coherent laser light) can in a delegated fashion prepare quantum states arbitrarily close to perfect random single qubit states. We finally prove that access to coherent states is sufficient to efficiently achieve approximate blindness with arbitrary small security parameter.

Vedran Dunjko; Elham Kashefi; Anthony Leverrier

2012-05-16T23:59:59.000Z

414

Coherent exciton dynamics in the presence of underdamped vibrations  

E-Print Network [OSTI]

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.

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

2014-12-22T23:59:59.000Z

415

Biophotons, coherence and photocount statistics: a critical review  

E-Print Network [OSTI]

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.

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

2015-02-25T23:59:59.000Z

416

Coherent versus measurement feedback: Linear systems theory for quantum information  

E-Print Network [OSTI]

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.

Naoki Yamamoto

2014-10-10T23:59:59.000Z

417

Steady quantum coherence in non-equilibrium environment  

E-Print Network [OSTI]

We study the steady state of a three-level system in contact with a non-equilibrium environment, which is composed of two independent heat baths at different temperatures. We derive a master equation to describe the non-equilibrium process of the system. For the three level systems with two dipole transitions, i.e., the $\\Lambda$-type and V-type, we find that the interferences of two transitions in a non-equilibrium environment can give rise to non-vanishing steady quantum coherence, namely, there exist non-zero off-diagonal terms in the steady state density matrix (in the energy representation). Moreover, the non-vanishing off-diagonal terms increase with the temperature difference of the two heat baths. Such interferences of the transitions were usually omitted by secular approximation, for it was usually believed that they only take effect in short time behavior and do not affect the steady state. Here we show that, in non-equilibrium systems, such omission would lead to the neglect of the steady quantum coherence.

Sheng-Wen Li; C. Y. Cai; C. P. Sun

2014-07-16T23:59:59.000Z

418

Coherent control of atomic transport in spinor optical lattices  

SciTech Connect (OSTI)

Coherent transport of atoms trapped in an optical lattice can be controlled by microwave-induced spin flips that correlate with site-to-site hopping. We study the controllability of homogeneous one-dimensional systems of noninteracting atoms in the absence of site addressability. Given these restrictions, we construct a deterministic protocol to map an initially localized Wannier state to a wave packet that is coherently distributed over n sites. As an example, we consider a one dimensional quantum walk in the presence of both realistic photon scattering and inhomogeneous broadening of the microwave transition due to the optical lattice. Using composite pulses to suppress errors, fidelities of over 95% can be achieved for a 25-step walk. We extend the protocol for state preparation to analytic solutions for arbitrary unitary maps given homogeneous systems and in the presence of time-dependent uniform forces. Such control is important for applications in quantum information processing, such as quantum computing and quantum simulations of condensed matter phenomena.

Mischuck, Brian; Deutsch, Ivan H.; Jessen, Poul S. [University of New Mexico (United States); University of Arizona (United States)

2010-02-15T23:59:59.000Z

419

SCORPIO: A 36-Core Research Chip Demonstrating Snoopy Coherence on a Scalable Mesh NoC with In-Network Ordering  

E-Print Network [OSTI]

In the many-core era, scalable coherence and on-chip interconnects are crucial for shared memory processors. While snoopy coherence is common in small multicore systems, directory-based coherence is the de facto choice for ...

Daya, Bhavya Kishor

2014-06-30T23:59:59.000Z

420

Quantum Coherence in a Superfluid Josephson Junction Supradeep Narayana and Yuki Sato  

E-Print Network [OSTI]

Quantum Coherence in a Superfluid Josephson Junction Supradeep Narayana and Yuki Sato The Rowland in which we take an array of nanoscale apertures that form a superfluid 4He Josephson junction and apply Josephson junctions as well as phase coherence among the superfluid aperture array are discussed. DOI: 10

Sato, Yuki

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Imaging Lignin-Downregulated Alfalfa Using Coherent Anti-Stokes Raman Scattering Microscopy  

E-Print Network [OSTI]

Imaging Lignin-Downregulated Alfalfa Using Coherent Anti-Stokes Raman Scattering Microscopy Yining-downregulated alfalfa lines were imaged using coherent anti-Stokes Raman scattering (CARS) microscopy. The 1,600-cm-1 (CARS) . Lignin-downregulated alfalfa Introduction Lignocellulosic biomass is under consideration

Xie, Xiaoliang Sunney

422

High-Resolution Optical Coherence Tomography-Guided Laser Ablation of Surgical Tissue1  

E-Print Network [OSTI]

High-Resolution Optical Coherence Tomography-Guided Laser Ablation of Surgical Tissue1 Stephen A Hospital, Boston, Massachusetts 02114 Submitted for publication September 17, 1998 Background. Optical coherence tomography (OCT) is a compact high-speed imaging technology which uses infrared light to acquire

Boppart, Stephen

423

Entangling two superconducting LC coherent modes via a superconducting flux qubit  

E-Print Network [OSTI]

Based on a pure solid-state device consisting of two superconducting LC circuits coupled to a superconducting flux qubit, we propose in this paper that the maximally entangled coherent states of the two LC modes can be generated for arbitrary coherent states through flux qubit controls.

Mei-Yu Chen; Matisse W. Y. Tu; Wei-Min Zhang

2009-11-10T23:59:59.000Z

424

Extended light scattering model incorporating coherence for thin-film silicon solar cells  

E-Print Network [OSTI]

Extended light scattering model incorporating coherence for thin-film silicon solar cells Thomas film solar cells. The model integrates coherent light propagation in thin layers with a direct, non potential for light trapping in textured thin film silicon solar cells. VC 2011 American Institute

Lenstra, Arjen K.

425

Coherent ultrafast pulse synthesis between an optical parametric oscillator and a laser  

E-Print Network [OSTI]

Coherent ultrafast pulse synthesis between an optical parametric oscillator and a laser Jinghua Sun* and Derryck T. Reid Ultrafast Optics Group, School of Engineering and Physical Sciences, Heriot 13, 2009 We have demonstrated coherent pulse synthesis between the carrier-envelope, phase

426

Coherent matter waves for ultrafast laser pulse characterization M. Winter, M. Wollenhaupt, T. Baumert *  

E-Print Network [OSTI]

Coherent matter waves for ultrafast laser pulse characterization M. Winter, M. Wollenhaupt, T for the characterization of ultrashort laser pulses using coherent matter waves is demonstrated. We emphasize the anal- ogy theoretically and experimentally and is the basis for our laser pulse character- ization technique. We use

Peinke, Joachim

427

Proceedings of SPIE, Vol. 5825, 118-138 (2005) Ultrafast coherent spectroscopy of single semiconductor  

E-Print Network [OSTI]

ultrafast optical pulses to probe and control coherent polarizations. In this article, we review our recentProceedings of SPIE, Vol. 5825, 118-138 (2005) Ultrafast coherent spectroscopy of single work on combining ultrafast spectroscopy and near-field microscopy to probe the nonlinear optical

Peinke, Joachim

428

Controlled Coherent Excitations in a Single Cadmium Ion with an Ultrafast Laser  

E-Print Network [OSTI]

of ultrafast pulses in a Ramsey interferometer. This ultrafast coupling is vital in a scheme for generationControlled Coherent Excitations in a Single Cadmium Ion with an Ultrafast Laser by Rudolph Nicolas: Controlled Coherent Excitations in a Single Cadmium Ion with an Ultrafast Laser written by R. N. Kohn Jr. has

Monroe, Christopher

429

Breathing coherent phonons and caps fragmentation in carbon nanotubes following ultrafast laser pulses  

E-Print Network [OSTI]

driven by ultrafast laser pulses.1­3 The necessary conditions for generating such coherent phonons are i is larger than the duration of currently available ultrafast pulses. ii Measurements4­7 determinedBreathing coherent phonons and caps fragmentation in carbon nanotubes following ultrafast laser

Dumitrica,Traian

430

Visual Design of coherent Technology-Enhanced Learning Systems: a few lessons learned from CPM language  

E-Print Network [OSTI]

Visual Design of coherent Technology-Enhanced Learning Systems: a few lessons learned from CPM Systems: a few lessons learned from CPM language Abstract. Visual instructional design languages currently Botturi ; Todd Stubbs (Ed.) (2007) 254-280" #12;-1- Visual Design of coherent Technology-Enhanced Learning

Paris-Sud XI, Université de

431

Algorithms for Categorizing Multiprocessor Communication Under Invalidate and UpdateBased Coherence Protocols \\Lambda  

E-Print Network [OSTI]

of useless traffic entailed by each coherence protocol. Under an invalidate­based protocol, our algorithms and Technology---HighPerformance Computing, Software Science and Tech­ nology program, ARPA Order no. 8930 to intro­ duce useless communication due to a mismatch between the hardware unit of coherence and the data

Bianchini, Ricardo

432

State Pruning for Test Vector Generation for a Multiprocessor Cache Coherence Protocol  

E-Print Network [OSTI]

fist search (BFS) to generate the frontier state, which is similar to [6]. Then each DFS search usesState Pruning for Test Vector Generation for a Multiprocessor Cache Coherence Protocol Ying Chen coherence protocol. Generating traces for system verification using a model checker and then using

Minnesota, University of

433

Coherent Multiresolution Isosurface Ray Tracing Aaron Knoll, Charles Hansen and Ingo Wald  

E-Print Network [OSTI]

-2007-001 Scientific Computing and Imaging Institute University of Utah Salt Lake City, UT 84112 USA1 Coherent Multiresolution Isosurface Ray Tracing Aaron Knoll, Charles Hansen and Ingo Wald UUSCI. Technical Report No UUSCI-2007-001 Coherent Multiresolution Isosurface Ray Tracing Aaron Knoll Charles

Utah, University of

434

Laser-Scanning Coherent Anti-Stokes Raman Scattering Microscopy and Applications to Cell Biology  

E-Print Network [OSTI]

Laser-Scanning Coherent Anti-Stokes Raman Scattering Microscopy and Applications to Cell Biology Ji 11747-3157 USA ABSTRACT Laser-scanning coherent anti-Stokes Raman scattering (CARS) microscopy with fast., 1990). Duncan et al. constructed the first CARS microscope by use of two dye laser beams

Xie, Xiaoliang Sunney

435

About a new family of coherent states for some SU(1,1) central field potentials  

SciTech Connect (OSTI)

In this paper, we shall define a new family of coherent states which we shall call the 'mother coherent states,' bearing in mind the fact that these states are independent from any parameter (the Bargmann index, the rotational quantum number J, and so on). So, these coherent states are defined on the whole Hilbert space of the Fock basis vectors. The defined coherent states are of the Barut-Girardello kind, i.e., they are the eigenstates of the lowering operator. For these coherent states we shall calculate the expectation values of different quantum observables, the corresponding Mandel parameter, the Husimi's distribution function and also the P- function. Finally, we shall particularize the obtained results for the three-dimensional harmonic and pseudoharmonic oscillators.

Popov, Dusan; Pop, Nicolina; Chiritoiu, Viorel [Department of Physical Foundations of Engineering, 'Politehnica' University of Timisoara, Bv. Vasile Parvan No. 2, RO-300223 Timisoara (Romania)] [Department of Physical Foundations of Engineering, 'Politehnica' University of Timisoara, Bv. Vasile Parvan No. 2, RO-300223 Timisoara (Romania); Sajfert, Vjekoslav [Technical Faculty 'M. Pupin' Zrenjanin, University of Novi Sad, Djure Djakovica bb, 23000 (Serbia)] [Technical Faculty 'M. Pupin' Zrenjanin, University of Novi Sad, Djure Djakovica bb, 23000 (Serbia)

2013-03-15T23:59:59.000Z

436

Characterization of the coherent noise, electromagnetic compatibility and electromagnetic interference of the ATLAS EM calorimeter Front End Board  

E-Print Network [OSTI]

Characterization of the coherent noise, electromagnetic compatibility and electromagnetic interference of the ATLAS EM calorimeter Front End Board

Chase, B E; Lanni, F; Makowiecki, D S; Radeka, V; Rescia, S; Takai, H; Bán, J; Parsons, J; Sippach, W

1999-01-01T23:59:59.000Z

437

Realignment-enhanced coherent anti-Stokes Raman scattering (CARS) and three-dimensional imaging in anisotropic fluids  

E-Print Network [OSTI]

We apply coherent anti-Stokes Raman Scattering (CARS) microscopy to characterize director structures in liquid crystals.

A. V. Kachynski; A. N. Kuzmin; P. N. Prasad; I. I. Smalyukh

2008-07-04T23:59:59.000Z

438

Macro-coherent two photon and radiative neutrino pair emission  

E-Print Network [OSTI]

We discuss a possibility of detecting a coherent photon pair emission and related radiative neutrino pair emission from excited atoms. It is shown that atoms of lambda- and ladder-type three level system placed in a pencil-like cylinder give a back to back emission of two photons of equal energy $\\Delta/2$, sharply peaked with a width $\\propto $ 1/(target size) and well collimated along the cylinder axis. This process has a measurable rate $\\propto$ (target number density) $^2 \\times$ target volume, while a broader spectral feature of one-photon distribution separated by (mass sum of a neutrino pair)$^2/(2\\Delta)$ from the two photon peak may arise from radiative neutrino pair emission, with a much smaller rate.

M. Yoshimura; C. Ohae; A. Fukumi; K. Nakajima; I. Nakano; H. Nanjo; N. Sasao

2008-05-14T23:59:59.000Z

439

f(R) Gravity, relic coherent gravitons and optical chaos  

E-Print Network [OSTI]

We discuss the production of massive relic coherent gravitons in a particular class of f(R) gravity which arises from string theory and their possible imprint in Cosmic Microwave Background. In fact, in the very early universe these relic gravitons could have acted as slow gravity waves. They may have then acted to focus the geodesics of radiation and matter. Therefore, their imprint on the later evolution of the universe could appear as filaments and domain wall in the Universe today. In that case, the effect on Cosmic Microwave Background should be analogous to the effect of water waves, which, in focusing light, create optical caustics which are commonly seen on the bottom of swimming pools. We analyze this important issue by showing how relic massive GWs perturb the trajectories of Cosmic Microwave Background photons (gravitational lensing by relic GWs). The consequence of the type of physics discussed is outlined by illustrating an amplification of what might be called optical chaos.

Lawrence B. Crowell; Christian Corda

2014-02-19T23:59:59.000Z

440

Transient Dynamics in Molecular Junctions: Coherent Bichromophoric Molecular Electron Pumps  

E-Print Network [OSTI]

The possibility of using single molecule junctions as electron pumps for energy conversion and storage is considered. It is argued that the small dimensions of these systems enable to make use of unique intra-molecular quantum coherences in order to pump electrons between two leads and to overcome relaxation processes which tend to suppress the pumping efficiency. In particular, we demonstrate that a selective transient excitation of one chromophore in a bi-chromophoric donor-bridge-acceptor molecular junction model yields currents which transfer charge (electron and holes) unevenly to the two leads in the absence of a bias potential. The utility of this mechanism for charge pumping in steady state conditions is proposed.

Roie Volkovich; Uri Peskin

2010-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Radio astronomical polarimetry and phase-coherent matrix convolution  

E-Print Network [OSTI]

A new phase-coherent technique for the calibration of polarimetric data is presented. Similar to the one-dimensional form of convolution, data are multiplied by the response function in the frequency domain. Therefore, the system response may be corrected with arbitrarily high spectral resolution, effectively treating the problem of bandwidth depolarization. As well, the original temporal resolution of the data is retained. The method is therefore particularly useful in the study of radio pulsars, where high time resolution and polarization purity are essential requirements of high-precision timing. As a demonstration of the technique, it is applied to full-polarization baseband recordings of the nearby millisecond pulsar, PSR J0437-4715.

W. van Straten

2001-11-21T23:59:59.000Z

442

Private Database Queries Using Quantum States with Limited Coherence Times  

E-Print Network [OSTI]

We describe a method for private database queries using exchange of quantum states with bits encoded in mutually incompatible bases. For technology with limited coherence time, the database vendor can announce the encoding after a suitable delay to allow the user to privately learn one of two items in the database without the ability to also definitely infer the second item. This quantum approach also allows the user to choose to learn other functions of the items, such as the exclusive-or of their bits, but not to gain more information than equivalent to learning one item, on average. This method is especially useful for items consisting of a few bits by avoiding the substantial overhead of conventional cryptographic approaches.

Tad Hogg; Li Zhang

2009-03-31T23:59:59.000Z

443

Atmospheric coherence times in interferometry: definition and measurement  

E-Print Network [OSTI]

Current and future ground-based interferometers require knowledge of the atmospheric time constant t_0, but this parameter has diverse definitions. Moreover, adequate techniques for monitoring t_0 still have to be implemented. We derive a new formula for the structure function of the fringe phase (piston) in a long-baseline interferometer, and review available techniques for measuring the atmospheric time constant and the shortcomings. It is shown that the standard adaptive-optics atmospheric time constant is sufficient for quantifying the piston coherence time, with only minor modifications. The residual error of a fast fringe tracker and the loss of fringe visibility in a finite exposure time are calculated in terms of the same parameter. A new method based on the fast variations of defocus is proposed. The formula for relating the defocus speed to the time constant is derived. Simulations of a 35-cm telescope demonstrate the feasibility of this new technique for site testing.

A. Kellerer; A. Tokovinin

2006-10-06T23:59:59.000Z

444

Selective coherence transfers in homonuclear dipolar coupled spin systems  

E-Print Network [OSTI]

Mapping the physical dipolar Hamiltonian of a solid-state network of nuclear spins onto a system of nearest-neighbor couplings would be extremely useful for a variety of quantum information processing applications, as well as NMR structural studies. We demonstrate such a mapping for a system consisting of an ensemble of spin pairs, where the coupling between spins in the same pair is significantly stronger than the coupling between spins on different pairs. An amplitude modulated RF field is applied on resonance with the Larmor frequency of the spins, with the frequency of the modulation matched to the frequency of the dipolar coupling of interest. The spin pairs appear isolated from each other in the regime where the RF power (omega_1) is such that omega_weak << omega_1 << omega_strong. Coherence lifetimes within the two-spin system are increased from 19 us to 11.1 ms, a factor of 572.

Chandrasekhar Ramanathan; Suddhasattwa Sinha; Jonathan Baugh; Timothy F. Havel; David G. Cory

2004-09-30T23:59:59.000Z

445

Ultrafast laser based coherent control methods for explosives detection  

SciTech Connect (OSTI)

The detection of explosives is a notoriously difficult problem, especially at stand-off, due to their (generally) low vapor pressure, environmental and matrix interferences, and packaging. We are exploring Optimal Dynamic Detection of Explosives (ODD-Ex), which exploits the best capabilities of recent advances in laser technology and recent discoveries in optimal shaping of laser pulses for control of molecular processes to significantly enhance the standoff detection of explosives. The core of the ODD-Ex technique is the introduction of optimally shaped laser pulses to simultaneously enhance sensitivity to explosives signatures while dramatically improving specificity, particularly against matrix materials and background interferences. These goals are being addressed by operating in an optimal non-linear fashion, typically with a single shaped laser pulse inherently containing within it coherently locked control and probe subpulses. Recent results will be presented.

Moore, David Steven [Los Alamos National Laboratory

2010-12-06T23:59:59.000Z

446

Cascaded injection resonator for coherent beam combining of laser arrays  

DOE Patents [OSTI]

The invention provides a cascaded injection resonator for coherent beam combining of laser arrays. The resonator comprises a plurality of laser emitters arranged along at least one plane and a beam sampler for reflecting at least a portion of each laser beam that impinges on the beam sampler, the portion of each laser beam from one of the laser emitters being reflected back to another one of the laser emitters to cause a beam to be generated from the other one of the laser emitters to the beam reflector. The beam sampler also transmits a portion of each laser beam to produce a laser output beam such that a plurality of laser output beams of the same frequency are produced. An injection laser beam is directed to a first laser emitter to begin a process of generating and reflecting a laser beam from one laser emitter to another laser emitter in the plurality. A method of practicing the invention is also disclosed.

Kireev, Vassili [Sunnyvale, CA; Liu, Yun; Protopopescu, Vladimir [Knoxville, TN; Braiman, Yehuda [Oak Ridge, TN

2008-10-21T23:59:59.000Z

447

Biophotons, coherence and photocount statistics: a critical review  

E-Print Network [OSTI]

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...

Cifra, Michal; Nerudová, Michaela; Ku?era, Ond?ej

2015-01-01T23:59:59.000Z

448

Coherent Control of a Single Silicon-29 Nuclear Spin Qubit  

E-Print Network [OSTI]

Magnetic fluctuations caused by the nuclear spins of a host crystal are often the leading source of decoherence for many types of solid-state spin qubit. In group-IV materials, the spin-bearing nuclei are sufficiently rare that it is possible to identify and control individual host nuclear spins. This work presents the first experimental detection and manipulation of a single $^{29}$Si nuclear spin. The quantum non-demolition (QND) single-shot readout of the spin is demonstrated, and a Hahn echo measurement reveals a coherence time of $T_2 = 6.3(7)$ ms - in excellent agreement with bulk experiments. Atomistic modeling combined with extracted experimental parameters provides possible lattice sites for the $^{29}$Si atom under investigation. These results demonstrate that single $^{29}$Si nuclear spins could serve as a valuable resource in a silicon spin-based quantum computer.

Jarryd J. Pla; Fahd A. Mohiyaddin; Kuan Y. Tan; Juan P. Dehollain; Rajib Rahman; Gerhard Klimeck; David N. Jamieson; Andrew S. Dzurak; Andrea Morello

2014-08-06T23:59:59.000Z

449

Coherent structures in ion temperature gradient turbulence-zonal flow  

SciTech Connect (OSTI)

Nonlinear stationary structure formation in the coupled ion temperature gradient (ITG)-zonal flow system is investigated. The ITG turbulence is described by a wave-kinetic equation for the action density of the ITG mode, and the longer scale zonal mode is described by a dynamic equation for the m?=?n?=?0 component of the potential. Two populations of trapped and untrapped drift wave trajectories are shown to exist in a moving frame of reference. This novel effect leads to the formation of nonlinear stationary structures. It is shown that the ITG turbulence can self-consistently sustain coherent, radially propagating modulation envelope structures such as solitons, shocks, and nonlinear wave trains.

Singh, Rameswar, E-mail: rameswar.singh@lpp.polytechnique.fr [Laboratoire de Physique des Plasmas, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau Cedex (France); Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); Singh, R. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Kaw, P. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); Gürcan, Ö. D. [Laboratoire de Physique des Plasmas, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau Cedex (France); Diamond, P. H. [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); CMTFO and CASS, University of California, San Diego, California 92093 (United States)

2014-10-15T23:59:59.000Z

450

Introduction Modeling of large ocean waves Propagation speed Coherent wavetrains Near-shore wave dynamics Conclusions Tsunamis and ocean waves  

E-Print Network [OSTI]

Introduction Modeling of large ocean waves Propagation speed Coherent wavetrains Near-shore wave waves #12;Introduction Modeling of large ocean waves Propagation speed Coherent wavetrains NearMaster University Tsunamis and ocean waves #12;Introduction Modeling of large ocean waves Propagation speed Coherent

Craig, Walter

451

X-ray laser frequency near-doubling and generation of tunable coherent x rays in plasma  

E-Print Network [OSTI]

X-ray laser frequency near-doubling and generation of tunable coherent x rays in plasma P. L plasmas in which efficient x-ray laser frequency near-doubling is expected for a number of available x-ray of coherent x rays and tunable optical radiation may result in tunable coherent x-ray radiation powerful

Kaplan, Alexander

452

Energy Impact Illinois  

Broader source: Energy.gov [DOE]

Presents how Energy Impact Illinois overcame barriers in the multifamily sector through financing partnerships and expert advice.

453

Spatio-temporal coherence of free-electron laser radiation in the extreme ultraviolet determined by a Michelson interferometer  

SciTech Connect (OSTI)

A key feature of extreme ultraviolet (XUV) radiation from free-electron lasers (FELs) is its spatial and temporal coherence. We measured the spatio-temporal coherence properties of monochromatized FEL pulses at 13.5?nm using a Michelson interferometer. A temporal coherence time of (59±8) fs has been determined, which is in good agreement with the spectral bandwidth given by the monochromator. Moreover, the spatial coherence in vertical direction amounts to about 15% of the beam diameter and about 12% in horizontal direction. The feasibility of measuring spatio-temporal coherence properties of XUV FEL radiation using interferometric techniques advances machine operation and experimental studies significantly.

Hilbert, V.; Rödel, C.; Zastrau, U., E-mail: ulf.zastrau@uni-jena.de [Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena (Germany); Brenner, G.; Düsterer, S.; Dziarzhytski, S.; Harmand, M.; Przystawik, A.; Redlin, H.; Toleikis, S. [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg (Germany); Döppner, T.; Ma, T. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States); Fletcher, L. [Department of Physics, University of California, Berkeley, California 94720 (United States); Förster, E. [Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena (Germany); Helmholtz-Institut Jena, Fröbelstieg 3, 07743 Jena (Germany); Glenzer, S. H.; Lee, H. J. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Hartley, N. J. [Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Kazak, L.; Komar, D.; Skruszewicz, S. [Institut für Physik, Universität Rostock, 18051 Rostock (Germany); and others

2014-09-08T23:59:59.000Z

454

Coherence Induced by Incoherent Pumping Field and Decay Process in Three-level $?$ Type Atomic System  

E-Print Network [OSTI]

Following the method of Victor V. Kozlov et al.[PhysRevA. 74. 063829],we inspect the coherence induced by incoherent pump and spontaneous decay process in $\\Lambda$ type three-level atomic system with degenerated lower duplicate levels. The system shows a coherent population trapping state and multi-steady states characteristic in different conditions. Interestingly, two kinds of steady states generated by the system in different sets of pumping and decaying parameters, the "singlet" state and the "triplet" state, exhibit stable or unstable characteristics under the action of pumping field and vacuum reservoir, which promise fruitful applications to atomic coherence and interference in quantum optics.

Bao-Quan Ou; Lin-Mei Liang; Cheng-Zu Li

2007-12-25T23:59:59.000Z

455

Coherent open-loop optimal control of light-harvesting dynamics  

E-Print Network [OSTI]

We apply theoretically open-loop quantum optimal control techniques to provide methods for the verification of various quantum coherent transport mechanisms in natural and artificial light-harvesting complexes under realistic experimental constraints. We demonstrate that optimally shaped laser pulses allow to faithfully prepare the photosystem in specified initial states (such as localized excitation or coherent superposition, i.e. propagating and non-propagating states) and to probe efficiently the dynamics. These results provide a path towards the discrimination of the different transport pathways and to the characterization of environmental properties, enhancing our understanding of the role that coherent processes may play in biological complexes.

Filippo Caruso; Simone Montangero; Tommaso Calarco; Susana F. Huelga; Martin B. Plenio

2011-03-04T23:59:59.000Z

456

Possibility of coherent phenomena such as Bloch oscillations with single photons via W states  

SciTech Connect (OSTI)

We examine the behavior of single photons at multiport devices and inquire if coherent effects are possible. In particular we study how single photons need to be manipulated in order to study coherent phenomena. We show that single photons need to be produced in W states which lead to vanishing mean amplitude but nonzero correlations between the inputs at different ports. Such correlations restore coherent effects with single photons. As a specific example we demonstrate Bloch oscillations with single photons and thus provide strict analog of Bloch oscillation of electrons.

Rai, Amit; Agarwal, G. S. [Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078 (United States)

2009-05-15T23:59:59.000Z

457

Two-photon interference with continuous-wave multi-mode coherent light  

E-Print Network [OSTI]

We report two-photon interference with continuous-wave multi-mode coherent light. We show that the two-photon interference, in terms of the detection time difference, reveals two-photon beating fringes with the visibility $V = 0.5$. While scanning the optical delay of the interferometer, Hong-Ou-Mandel dips or peaks are measured depending on the chosen detection time difference. The HOM dips/peaks are repeated when the optical delay and the first-order coherence revival period of the multi-mode coherent light are the same.

Yong-Su Kim; Oliver Slattery; Paulina S. Kuo; Xiao Tang

2013-09-12T23:59:59.000Z

458

Symmetrical and anti-symmetrical coherent perfect absorption for acoustic waves  

SciTech Connect (OSTI)

We investigate tunable acoustic absorption enabled by the coherent control of input waves. It relies on coherent perfect absorption originally proposed in optics. By designing appropriate acoustic metamaterial structures with resonating effective bulk modulus or density, we show that complete absorption of incident waves impinging on the metamaterial can be achieved for either symmetrical or anti-symmetrical inputs in the forward and backward directions. By adjusting the relative phase between the two incident beams, absorption can be tuned effectively from unity to zero, making coherent control useful in applications like acoustic modulators, noise controllers, transducers, and switches.

Wei, Pengjiang; Croënne, Charles; Tak Chu, Sai [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Li, Jensen, E-mail: j.li@bham.ac.uk [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom)

2014-03-24T23:59:59.000Z

459

On-chip COMA Cache-coherence protocol for Microgrids of Microthreaded Cores  

E-Print Network [OSTI]

On-chip COMA Cache-coherence protocol for Microgrids of Microthreaded Cores Li Zhang Chris Jesshope and the development of a co-simulator to the Microgrid CMP emulator. 1 Introduction It is now widely accepted

Jesshope, Chris

460

Noise figure and photon statistics in coherent anti-Stokes Raman scattering  

E-Print Network [OSTI]

). 11. J. Perina, "Photon statistics in Raman scattering with frequency mismatch," Optica Acta 28, 1529 (1981). 12. J. Perina, "Photon statistics in Raman scattering of intense coherent light," Optica Acta 28

Jalali. Bahram

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Phase coherence in multiple scattering : weak and intense monochromatic light wave propagating in a cold strontium  

E-Print Network [OSTI]

in a cold strontium cloud David Wilkowski, Yannick Bidel, Thierry Chaneli`ere, Robin Kaiser, Bruce Klappauf coherence of a monochromatic laser light propagating in an optically thick sample of laser-cooled strontium

462

Applications of Fourier Domain Mode Locked lasers for optical coherence tomography imaging  

E-Print Network [OSTI]

Optical coherence tomography (OCT) is a micrometer-resolution imaging technique that produces cross-sectional images of sample microstructure by measuring the amplitude and echo time delay of backscattered light. OCT imaging ...

Adler, Desmond Christopher, 1978-

2009-01-01T23:59:59.000Z

463

Phase shift of a weak coherent beam induced by a single atom  

E-Print Network [OSTI]

We report on a direct measurement of a phase shift on a weak coherent beam by a single Rb-87 atom in a Mach-Zehnder interferometer. A maximum phase shift of about 1 degree is observed experimentally.

Syed Abdullah Aljunid; Meng Khoon Tey; Brenda Chng; Timothy Liew; Gleb Maslennikov; Valerio Scarani; Christian Kurtsiefer

2009-05-22T23:59:59.000Z

464

Detection of bacterial endospores by means of ultrafast coherent raman spectroscopy  

E-Print Network [OSTI]

This work is devoted to formulation and development of a laser spectroscopic technique for rapid detection of biohazards, such as Bacillus anthracis spores. Coherent anti-Stokes Raman scattering (CARS) is used as an underlying process for active...

Pestov, Dmitry Sergeyevich

2008-10-10T23:59:59.000Z

465

High-Intensity Coherent Vacuum Ultraviolet Source Using Unfocussed Commercial Dye Lasers  

E-Print Network [OSTI]

1 High-Intensity Coherent Vacuum Ultraviolet Source Using Unfocussed Commercial Dye Lasers Daniel R Intruments Using two or three commercial pulsed nanosecond dye lasers pumped by a single 30 Hz Nd:YAG laser

Davis, H. Floyd

466

High-resolution three-dimensional optical coherence tomography imaging of kidney microanatomy ex vivo  

E-Print Network [OSTI]

Optical coherence tomography (OCT) is an emerging medical imaging technology that enables high-resolution, noninvasive, cross-sectional imaging of microstructure in biological tissues in situ and in real time. When combined ...

Chen, Yu

467

Use of Neck Strap Muscle Intermuscular Coherence as an Indicator of Vocal Hyperfunction  

E-Print Network [OSTI]

Intermuscular coherence in the beta band was explored as a possible indicator of vocal hyperfunction, a common condition associated with many voice disorders. Surface electromyography (sEMG) was measured from two electrodes ...

Heaton, James T.

468

Coherent Control of Resonant Two-Photon Transitions by Counter-Propagating Ultrashort Pulse Pairs  

E-Print Network [OSTI]

We describe optimized coherent control methods for two-photon transitions in atoms of a ladder-type three-state energy configuration. Our approach is based on the spatial coherent control scheme which utilizes counter-propagating ultrashort laser pulses to produce complex excitation patterns in an extended space. Since coherent control requires constructive interference of constituent transition pathways, applying it to an atomic transition with a specific energy configuration requires specially designed laser pulses. Here, we show, in an experimental demonstration, that the two-photon transition with an intermediate resonant energy state can be coherently controlled and retrieved out from the resonance-induced background, when phase-flipping of the laser spectrum near the resonant intermediate transition is used. A simple reason for this behavior is the fact that the transition amplitude function (to be added to give an overall two-photon transition) changes its sign at the intermediate resonant frequency, t...

Lee, Woojun; Kim, Kyungtae; Ahn, Jaewook

2015-01-01T23:59:59.000Z

469

Method for Quantitative Study of Airway Functional Microanatomy Using Micro-Optical Coherence Tomography  

E-Print Network [OSTI]

We demonstrate the use of a high resolution form of optical coherence tomography, termed micro-OCT (?OCT), for investigating the functional microanatomy of airway epithelia. ?OCT captures several key parameters governing ...

Diephuis, Bradford J.

470

One-step continuous synthesis of biocompatible gold nanorods for optical coherence tomography  

E-Print Network [OSTI]

We present a novel one-step flow process to synthesize biocompatible gold nanorods with tunable absorption and biocompatible surface ligands. Photothermal optical coherence tomography (OCT) of human breast tissue is ...

Sebastián, Víctor

471

Two-dimensional ultrafast pulse shaping and its application to coherent control and spectroscopy  

E-Print Network [OSTI]

This thesis develops powerful new methods for shaping femtosecond laser pulses in two dimensions and explores their application to coherent control of propagating lattice excitations and degenerate four-wave mixing ...

Vaughan, Joshua Charles

2005-01-01T23:59:59.000Z

472

Phase-sensitive light : coherence theory and applications to optical imaging  

E-Print Network [OSTI]

Spontaneous parametric downconversion (SPDC) can produce pairs of entangled photons, i.e., a stream of biphotons. SPDC has been utilized in a number of optical imaging applications, such as optical coherence tomography, ...

Erkmen, Baris Ibrahim, 1980-

2008-01-01T23:59:59.000Z

473

Coherent-feedback-induced photon blockade and optical bistability by an optomechanical controller  

E-Print Network [OSTI]

It is well-known that some nonlinear phenomena such as strong photon blockade are hard to be observed in optomechanical system with current experimental technology. Here, we present a coherent feedback control strategy in which a linear cavity is coherently controlled by an optomechanical controller in a feedback manner. The coherent feedback loop transfers and enhances quantum nonlinearity from the controller to the controlled cavity, which makes it possible to observe strong nonlinear effects in either linear cavity or optomechanical cavity. More interestingly, we find that the strong photon blockade under single-photon optomechanical weak coupling condition could be observed in the quantum regime. Additionally, the coherent feedback loop leads to two-photon and multiphoton tunnelings for the controlled linear cavity, which are also typical quantum nonlinear phenomenon. We hope that our work can give new perspectives in engineering nonlinear quantum phenomena.

Yu-Long Liu; Zhong-Peng Liu; Jing Zhang; Yu-xi Liu

2014-07-11T23:59:59.000Z

474

Atherosclerotic tissue characterization in vivo by optical coherence tomography attenuation imaging  

E-Print Network [OSTI]

Optical coherence tomography (OCT) is rapidly becoming the method of choice for assessing arterial wall pathology in vivo. Atherosclerotic plaques can be diagnosed with high accuracy, including measurement of the thickness ...

Tearney, Guillermo J.

475

Optical coherence tomography based on intensity correlations of quasi-thermal light  

E-Print Network [OSTI]

We show theoretically that the longitudinal resolution of conventional optical coherence tomography can be improved by a factor of radic2 when a two-photon (as opposed to a single-photon) sensitive detector is used, and ...

Zerom, Petros

476

ELECTRON BUNCH PROFILE DIAGNOSTICS IN THE FEW FS REGIME USING COHERENT SMITH-PURCELL RADIATION  

E-Print Network [OSTI]

', which is essential for the accurate reconstruction of the temporal bunch profile. INTRODUCTION New bunch length and profiles measurements down to the few fs FWHM regime. Coherent Smith-Purcell (CSP

Paris-Sud XI, Université de

477

Simplifying and speeding the management of intra-node cache coherence  

DOE Patents [OSTI]

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.

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, Phillip (Cortlandt Manor, NY); Hoenicke, Dirk (Ossining, NY); Ohmacht, Martin (Yorktown Heights, NY)

2012-04-17T23:59:59.000Z

478

Design and implementation of a fiber optic doppler optical coherence microscopy system for cochlear imaging  

E-Print Network [OSTI]

In this thesis, the design and implementation of a fiber optic Doppler optical coherence microscopy (FO-DOCM) system for cochlear imaging applications is presented. The use of a fiber optic design significantly reduces ...

Williams, Logan P

2014-01-01T23:59:59.000Z

479

No Evidence for Coherent Diffractive Radiation Patterns in the Millisecond Pulsar PSR J0437-4715  

E-Print Network [OSTI]

An independent analysis of the 326.5 MHz data obtained by Ooty Radio Telescope reveals no evidence for coherent diffractive radiation patterns in the millisecond pulsar PSR J0437-4715.

M. Vivekanand

2001-05-28T23:59:59.000Z

480

Coherence and population dynamics of chlorophyll excitations in FCP complex: Two-dimensional spectroscopy study  

E-Print Network [OSTI]

The energy transfer processes and coherent phenomena in the fucoxanthin-chlorophyll protein complex, which is responsible for the light harvesting function in marine algae diatoms, were investigated at 77 K by using two-dimensional electronic spectroscopy. Experiments performed on the femtosecond and picosecond timescales led to separation of spectral dynamics, witnessing evolutions of coherence and population states of the system in the spectral region of ${\\rm Q}_{y}$ transitions of chlorophylls $a$ and $c$. Analysis of the coherence dynamics allowed us to identify chlorophyll (Chl) $a$ and fucoxanthin intramolecular vibrations dominating over the first few picoseconds. Closer inspection of the spectral region of the ${\\rm Q}_{y}$ transition of Chl $c$ revealed previously not identified mutually non-interacting chlorophyll $c$ states participating in femtosecond or picosecond energy transfer to the Chl $a$ molecules. Consideration of separated coherent and incoherent dynamics allowed us to hypothesize the v...

Butkus, Vytautas; Augulis, Ram?nas; Gall, Andrew; Büchel, Claudia; Robert, Bruno; Zigmantas, Donatas; Valkunas, Leonas; Abramavicius, Darius

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "impact linac coherent" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Digital signal processing techniques for optical coherence tomography : OCT and OCT image enhancement  

E-Print Network [OSTI]

Digital signal processing (DSP) techniques were developed to improve the flexibility, functionality, and image quality of ultrahigh resolution optical coherence tomography (OCT) systems. To reduce the dependence of OCT ...

Adler, Desmond Christopher, 1978-

2004-01-01T23:59:59.000Z

482

Coherent lattice and molecular dynamics in ultrafast single-shot spectroscopy  

E-Print Network [OSTI]

This thesis focuses on the development, refinement, and application of dual- echelon single-shot ultrafast spectroscopy to the study of coherent nuclear motion in condensed phase systems. The general principles of the ...

Poulin, Peter Roland, 1973-

2005-01-01T23:59:59.000Z

483

Optimal coherent control of dissipative N-level systems  

SciTech Connect (OSTI)

General optimal coherent control of dissipative N-level systems in the Markovian time regime is formulated within Pointryagin's principle and the Lindblad equation. In the present paper, we study feasibility and limitations of steering of dissipative two-, three-, and four-level systems from a given initial pure or mixed state into a desired final state under the influence of an external electric field. The time evolution of the system is computed within the Lindblad equation and a conjugate gradient method is used to identify optimal control fields. The influence of both field-independent population and polarization decay on achieving the objective is investigated in systematic fashion. It is shown that, for realistic dephasing times, optimum control fields can be identified which drive the system into the target state with very high success rate and in economical fashion, even when starting from a poor initial guess. Furthermore, the optimal fields obtained give insight into the system dynamics. However, if decay rates of the system cannot be subjected to electromagnetic control, the dissipative system cannot be maintained in a specific pure or mixed state, in general.

Jirari, H.; Poetz, W. [Institut fuer Theoretische Physik, Karl-Franzens-Universitaet Graz, Universitaetsplatz 5, 8010 Graz (Austria)

2005-07-15T23:59:59.000Z

484

Proposal for a phase-coherent thermoelectric transistor  

SciTech Connect (OSTI)

Identifying materials and devices which offer efficient thermoelectric effects at low temperature is a major obstacle for the development of thermal management strategies for low-temperature electronic systems. Superconductors cannot offer a solution since their near perfect electron-hole symmetry leads to a negligible thermoelectric response; however, here we demonstrate theoretically a superconducting thermoelectric transistor which offers unparalleled figures of merit of up to ?45 and Seebeck coefficients as large as a few mV/K at sub-Kelvin temperatures. The device is also phase-tunable meaning its thermoelectric response for power generation can be precisely controlled with a small magnetic field. Our concept is based on a superconductor-normal metal-superconductor interferometer in which the normal metal weak-link is tunnel coupled to a ferromagnetic insulator and a Zeeman split superconductor. Upon application of an external magnetic flux, the interferometer enables phase-coherent manipulation of thermoelectric properties whilst offering efficiencies which approach the Carnot limit.

Giazotto, F., E-mail: giazotto@sns.it [NEST, Instituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa (Italy); Robinson, J. W. A., E-mail: jjr33@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Moodera, J. S. [Department of Physics and Francis Bitter Magnet Lab, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Bergeret, F. S., E-mail: sebastian-bergeret@ehu.es [Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, Manuel de Lardizabal 4, E-20018 San Sebastián (Spain); Donostia International Physics Center (DIPC), Manuel de Lardizabal 5, E-20018 San Sebastián (Spain)

2014-08-11T23:59:59.000Z

485

Coherence-enhanced efficiency of feedback-driven quantum engines  

E-Print Network [OSTI]

A genuine feature of projective quantum measurements is that they inevitably alter the mean energy of the observed system if the measured quantity does not commute with the Hamiltonian. Compared to the classical case, Jacobs proved that this additional energetic cost leads to a stronger bound on the work extractable after a single measurement from a system initially in thermal equilibrium [Phys. Rev. A 80, 012322 (2009)]. Here, we extend this bound to a large class of feedback-driven quantum engines operating periodically and in finite time. The bound thus implies a natural definition for the efficiency of information to work conversion in such devices. For a simple model consisting of a laser-driven two-level system, we maximize the efficiency with respect to the observable whose measurement is used to control the feedback operations. We find that the optimal observable typically does not commute with the Hamiltonian and hence would not be available in a classical two level system. This result reveals that periodic feedback engines operating in the quantum realm can exploit quantum coherences to enhance efficiency.

Kay Brandner; Michael Bauer; Michael T. Schmid; Udo Seifert

2015-03-16T23:59:59.000Z

486

Coherent Image Layout using an Adaptive Visual Vocabulary  

SciTech Connect (OSTI)

When querying a huge image database containing millions of images, the result of the query may still contain many thousands of images that need to be presented to the user. We consider the problem of arranging such a large set of images into a visually coherent layout, one that places similar images next to each other. Image similarity is determined using a bag-of-features model, and the layout is constructed from a hierarchical clustering of the image set by mapping an in-order traversal of the hierarchy tree into a space-filling curve. This layout method provides strong locality guarantees so we are able to quantitatively evaluate performance using standard image retrieval benchmarks. Performance of the bag-of-features method is best when the vocabulary is learned on the image set being clustered. Because learning a large, discriminative vocabulary is a computationally demanding task, we present a novel method for efficiently adapting a generic visual vocabulary to a particular dataset. We evaluate our clustering and vocabulary adaptation methods on a variety of image datasets and show that adapting a generic vocabulary to a particular set of images improves performance on both hierarchical clustering and image retrieval tasks.

Dillard, Scott E.; Henry, Michael J.; Bohn, Shawn J.; Gosink, Luke J.

2013-03-06T23:59:59.000Z

487

Quantum computation mediated by ancillary qudits and spin coherent states  

E-Print Network [OSTI]

Models of universal quantum computation in which the required interactions between register (computational) qubits are mediated by some ancillary system are highly relevant to experimental realisations of a quantum computer. We introduce such a universal model that employs a $d$-dimensional ancillary qudit. The ancilla-register interactions take the form of controlled displacements operators, with a displacement operator defined on the periodic and discrete lattice phase space of a qudit. We show that these interactions can implement controlled phase gates on the register by utilising geometric phases that are created when closed loops are traversed in this phase space. The extra degrees of freedom of the ancilla can be harnessed to reduce the number of operations required for certain gate sequences. In particular, we see that the computational advantages of the quantum bus (qubus) architecture, which employs a field-mode ancilla, are also applicable to this model. We then explore an alternative ancilla-mediated model which employs a spin-ensemble as the ancillary system and again the interactions with the register qubits are via controlled displacement operators, with a displacement operator defined on the Bloch sphere phase space of the spin coherent states of the ensemble. We discuss the computational advantages of this model and its relationship with the qubus architecture.

Timothy J. Proctor; Shane Dooley; Viv Kendon

2014-12-09T23:59:59.000Z

488

Integrated information storage and transfer with a coherent magnetic device  

E-Print Network [OSTI]

Tackling heat dissipation in electronic devices is an ultimate goal of information technology. Quantum systems are inherently dissipation-less, making them excellent candidates even for classical information processing. We propose to use an array of large-spin quantum magnets for realizing a device which has two modes of operation: memory and data-bus. While the weakly interacting low-energy levels are used as memory to store classical information (bits), the high-energy levels strongly interact with neighboring magnets and mediate the spatial movement of information through quantum dynamics. Despite the fact that memory and data-bus require different features, which are usually prerogative of different physical systems -- well isolation for the memory cells, and strong interactions for the transmission -- our proposal avoids the notorious complexity of hybrid structures. The proposed mechanism can be realized with different setups. We specifically show that molecular magnets, as the most promising technology, can implement hundreds of operations within their coherence time, while adatoms on surfaces probed by a scanning tunneling microscope is a future possibility.

Ning Jia; Leonardo Banchi; Abolfazl Bayat; Guangjiong Dong; Sougato Bose

2015-02-12T23:59:59.000Z

489

Coherence effects in deep inelastic scattering from nuclei  

SciTech Connect (OSTI)

A complete theoretical picture of multiple scattering processes in QCD remains elusive. In deep inelastic scattering experiments (DIS), we hope to find out information about the internal structure of nuclei from inelastically scattering high-energy electrons off them. The electrons interact via virtual photon exchange with the target. In the target rest frame the virtual photon splits into a quark-antiquark pair which is then scattered off the target color field. At high energies, coherent multiple scattering within the nucleus takes place. We develop a model that uses a parameterization of scattering cross section of the quark-antiquark pair off the proton to predict the cross section suppression known as shadowing in larger nuclei. This model takes the possibility of multiple scattering into account using Glauber high-energy collision theory. In large nuclei we must also move beyond the eikonal approximation by correcting for the finite lifetime of the quark-antiquark pair inside the nucleus. Results and implications of this model in relation to available data will be discussed. Finally, application of this type of model to predicting gluon densities will be considered. Understanding this process can give us insights into the more oomplicated scattering taking place in heavy ion colliders such as RHIC and LHC.

Ver Steeg, G. L. (Greg L.); Raufeisen, J. (Jorg)

2001-01-01T23:59:59.000Z

490

Optimal coherent control of CARS: signal enhancement and background elimination  

E-Print Network [OSTI]

The ability to enhance resonant signals and eliminate the non-resonant background is analyzed for Coherent Anti-Stokes Raman Scattering (CARS). The analysis is done at a specific frequency as well as for broadband excitation using femtosecond pulse-shaping techniques. An appropriate objective functional is employed to balance resonant signal enhancement against non-resonant background suppression. Optimal enhancement of the signal and minimization of the background can be achieved by shaping the probe pulse alone while keeping the pump and Stokes pulses in transform-limited-form (TLF). In some cases analytical forms for the probe pulse can be found, and numerical simulations are carried out for other circumstances. It is found that a good approximate solution for the optimal pulse in the two-pulse CARS is a superposition of linear and arctangent type phases for the pump. The well-known probe delay method is shown to be a quasi-optimal scheme for background suppression. The results should provide a basis to improve the performance of CARS spectroscopy and microscopy.

Fang Gao; Feng Shuang; JunHui Shi; Herschel Rabitz; HaiFeng Wang; JiXin Cheng

2012-03-28T23:59:59.000Z

491

Coherent Integration of Databases by Abductive Logic Programming  

E-Print Network [OSTI]

We introduce an abductive method for a coherent integration of independent data-sources. The idea is to compute a list of data-facts that should be inserted to the amalgamated database or retracted from it in order to restore its consistency. This method is implemented by an abductive solver, called Asystem, that applies SLDNFA-resolution on a meta-theory that relates different, possibly contradicting, input databases. We also give a pure model-theoretic analysis of the possible ways to `recover' consistent data from an inconsistent database in terms of those models of the database that exhibit as minimal inconsistent information as reasonably possible. This allows us to characterize the `recovered databases' in terms of the `preferred' (i.e., most consistent) models of the theory. The outcome is an abductive-based application that is sound and complete with respect to a corresponding model-based, preferential semantics, and -- to the best of our knowledge -- is more expressive (thus more general) than any ot...

Arieli, O; Denecker, M; Van Nuffelen, B; 10.1613/jair.1322

2011-01-01T23:59:59.000Z

492

Coherent Scattering Investigations at the Spallation Neutron Source: a Snowmass White Paper  

SciTech Connect (OSTI)

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, Tennessee, provides an intense flux of neutrinos in the few tens-of-MeV range, with a sharply-pulsed timing structure that is beneficial for background rejection. In this white paper, we describe how the SNS source can be used for a measurement of coherent elastic neutrino-nucleus scattering (CENNS), and the physics reach of different phases of such an experimental program (CSI: Coherent Scattering Investigations at the SNS).

Akimov, D. [Moscow Engineering Physics Institute (MEPhI), Russia] Moscow Engineering Physics Institute (MEPhI), Russia; Bernstein, A. [Lawrence Livermore National Laboratory (LLNL)] Lawrence Livermore National Laboratory (LLNL); BarbeauP., [Duke University; Barton, P. J. [Lawrence Berkeley National Laboratory (LBNL)] Lawrence Berkeley National Laboratory (LBNL); Bolozdynya, A. [Moscow Engineering Physics Institute (MEPhI), Russia] Moscow Engineering Physics Institute (MEPhI), Russia; Cabrera-Palmer, B. [Sandia National Laboratories (SNL)] Sandia National Laboratories (SNL); Cavanna, F. [Yale University] Yale University; Cianciolo, Vince [ORNL] ORNL; Collar, J. [University of Chicago, Enrico Fermi Institute] University of Chicago, Enrico Fermi Institute; Cooper, R. J. [Indiana University] Indiana University; Dean, D. J. [Oak Ridge National Laboratory (ORNL)] Oak Ridge National Laboratory (ORNL); Efremenko, Yuri [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL)] University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Etenko, A. [Moscow Engineering Physics Institute (MEPhI), Russia] Moscow Engineering Physics Institute (MEPhI), Russia; Fields, N. [University of Chicago, Enrico Fermi Institute] University of Chicago, Enrico Fermi Institute; Foxe, M. [Pennsylvania State University, University Park, PA] Pennsylvania State University, University Park, PA; Figueroa-Feliciano, E. [Massachusetts Institute of Technology (MIT)] Massachusetts Institute of Technology (MIT); Fomin, N. [University of Tennessee, Knoxville (UTK)] University of Tennessee, Knoxville (UTK); Gallmeier, F. [Oak Ridge National Laboratory (ORNL)] Oak Ridge National Laboratory (ORNL); Garishvili, I. [University of Tennessee, Knoxville (UTK)] University of Tennessee, Knoxville (UTK); Gerling, M. [Sandia National Laboratories (SNL)] Sandia National Laboratories (SNL); Green, M. [University of North Carolina, Chapel Hill] University of North Carolina, Chapel Hill; Greene, Geoffrey [University of Tennessee, Knoxville (UTK)] University of Tennessee, Knoxville (UTK); Hatzikoutelis, A. [University of Tennessee, Knoxville (UTK)] University of Tennessee, Knoxville (UTK); Henning, Reyco [University of North Carolina, Chapel Hill] University of North Carolina, Chapel Hill; Hix, R. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL)] University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Hogan, D. [University of California-Berkeley] University of California-Berkeley; Hornback, D. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL)] University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Jovanovic, I. [Pennsylvania State University, University Park, PA] Pennsylvania State University, University Park, PA; Hossbach, T. [Pacific Northwest National Laboratory (PNNL)] Pacific Northwest National Laboratory (PNNL); Iverson, Erik B [ORNL] ORNL; Klein, S. R. [Lawrence Berkeley National Laboratory (LBNL)] Lawrence Berkeley National Laboratory (LBNL); Khromov, A. [Moscow Engineering Physics Institute (MEPhI), Russia] Moscow Engineering Physics Institute (MEPhI), Russia; Link, J. [Virginia Polytechnic Institute and State University] Virginia Polytechnic Institute and State University; Louis, W. [Los Alamos National Laboratory (LANL)] Los Alamos National Laboratory (LANL); Lu, W. [Oak Ridge National Laboratory (ORNL)] Oak Ridge National Laboratory (ORNL); Mauger, C. [Los Alamos National Laboratory (LANL)] Los Alamos National Laboratory (LANL); Marleau, P. [Sandia National Laboratories (SNL)] Sandia National Laboratories (SNL); Markoff, D. [North Carolina Central University, Durham] North Carolina Central University, Durham; Martin, R. D. [University of South Dakota] University of South Dakota; Mueller, Paul Edward [ORNL] ORNL; Newby, J. [Oak Ridge National Laboratory (ORNL)] Oak Ridge National Laboratory (ORNL); Orrell, John L. [Pacific Northwest National Laboratory (PNNL)] Pacific Northwest National Laboratory (PNNL); O'Shaughnessy, C. [University of North Carolina, Chapel Hill] University of North Carolina, Chapel Hill

2013-01-01T23:59:59.000Z

493

Noise-induced quantum coherence in photosynthetic complexes with multiple energy transfer pathways  

E-Print Network [OSTI]

We theoretically investigate exciton relaxation dynamics in molecular aggregates based on model photosynthetic complexes under various conditions of incoherent excitation. We show that noise-induced quantum coherence is generated between spatially-separated exciton states which belong to the same or different energy transfer pathways, coupled via real and virtual transfer processes. Such quantum coherence effects may be used to improve light-harvesting efficiency and to reveal quantum phenomena in biology.

Dmitri V. Voronine; Konstantin E. Dorfman; Bin Cao; Amitabh Joshi

2014-08-12T23:59:59.000Z

494

Measuring short electron bunch lengths using coherent Smith-Purcell radiation  

DOE Patents [OSTI]

A method is provided for directly determining the length of sub-picosecond electron bunches. A metallic grating is formed with a groove spacing greater than a length expected for the electron bunches. The electron bunches are passed over the metallic grating to generate coherent and incoherent Smith-Purcell radiation. The angular distribution of the coherent Smith-Purcell radiation is then mapped to directly deduce the length of the electron bunches. 8 figs.

Nguyen, D.C.

1999-03-30T23:59:59.000Z

495

Apparatus and method for improving radiation coherence and reducing beam emittance  

DOE Patents [OSTI]

A method and apparatus for increasing the coherence and reducing the emittance of a beam-shaped pulse operates by splitting the pulse into multiple sub-beams, delaying the propagation of the various sub-beams by varying amounts, and then recombining the sub-beams by means of a rotating optical element to form a pulse of longer duration with improved transverse coherence. 16 figs.

Csonka, P.L.

1992-05-12T23:59:59.000Z

496

Apparatus and method for improving radiation coherence and reducing beam emittance  

DOE Patents [OSTI]

A method and apparatus for increasing the coherence and reducing the emittance of a beam-shaped pulse operates by splitting the pulse into multiple sub-beams, delaying the propagation of the various sub-beams by varying amounts, and then recombining the sub-beams by means of a rotating optical element to form a pulse of longer duration with improved transverse coherence.

Csonka, Paul L. (105 E. 39th Ave., Eugene, OR 97405)

1992-01-01T23:59:59.000Z

497

Measuring short electron bunch lengths using coherent smith-purcell radiation  

DOE Patents [OSTI]

A method is provided for directly determining the length of sub-picosecond electron bunches. A metallic grating is formed with a groove spacing greater than a length expected for the electron bunches. The electron bunches are passed over the metallic grating to generate coherent and incoherent Smith-Purcell radiation. The angular distribution of the coherent Smith-Purcell radiation is then mapped to directly deduce the length of the electron bunches.

Nguyen, Dinh C. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

498

Application of Coherent State Approach for the cancellation of Infrared divergences to all orders in LFQED  

E-Print Network [OSTI]

We sketch an all order proof of cancellation of infrared (IR) divergences in Light Front Quantum Electrodynamics (LFQED) using a coherent state formalism. In this talk, it has been shown that the true IR divergences in fermion self energy are eliminated to all orders in a light-front time-ordered perturbative calculation if one uses coherent state basis instead of the usual Fock basis to calculate the Hamiltonian matrix elements.

More, Jai

2015-01-01T23:59:59.000Z

499

A study of the coherent structures and installation effects in an orifice flow meter  

E-Print Network [OSTI]

. Errors on the order of approximately 250 millions of dollar per year have been estimated for the natural gas industry. The urgent need to improve the accuracy has fueled basic research in the area of orifice flow meters. The objectives of this present... study were to analyze the coherent structures present in an orifice flow meter, and to examine the effect of a flow conditioner placed upstream of the orifice plate on the flow meter's accuracy, The coherent structures were measured by performing...

Pattabhi, Srikanth

2012-06-07T23:59:59.000Z

500

Equivalent sets of coherent states of the 1D infinite square well and properties  

E-Print Network [OSTI]

We prove the equivalence (under some conditions) of two sets of coherent states built for the one-dimensional infinite square well: the so-called generalized and Gaussian Klauder coherent states. We then derive an approximate close expression approaching their probability density and wave function to explore their properties analytically. This process gives thereby explanation of the quasi-classical behavior of these states in terms of the main observables and the Heisenberg uncertainty product

Marc-Antoine Fiset; Véronique Hussin

2014-10-01T23:59:59.000Z