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1

FINDING OF NO SIGNIFICANT IMPACT FOR LINAC COHERENT LIGHT SOURCE-Il  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

FINDING FINDING OF NO SIGNIFICANT IMPACT FOR LINAC COHERENT LIGHT SOURCE-Il PROJECT SLAC NATIONAL ACCELERATOR LABORATORY AGENCY: U. S. Department of Energy (DOE) ACTION: Finding of No Significant Impact (FONSI) SUMMARY: The U. S. Department of Energy (DOE) has completed an Environmental Assessment (DOE/EA-1904) on a project to expand the existing Linac Coherent Light Source (LCLS) facility at the SLAC National Accelerator Laboratory (SLAC). One of SLAC's major scientific facilities is the LCLS, the world's first hard X-ray free electron laser. The LCLS X-ray laser beams enable the simultaneous investigation of a material's electronic and structural properties on the size (sub-nanometer) and time (femto-second) scales that determine their function. Research programs at SLAC include materials science, catalytic sciences, structural molecular biology, and molecular environmental

2

Status of the Linac Coherent Light Source  

Science Conference Proceedings (OSTI)

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

Galayda, John N.; /SLAC

2011-11-04T23:59:59.000Z

3

SLAC Linac Coherent Light Source  

NLE Websites -- All DOE Office Websites (Extended Search)

LCLS Sign In Launch the Developer Dashboard SLAC National Accelerator Laboratory DOE | Stanford | SLAC | SSRL | LCLS | AD | PPA | Photon Science | PULSE | SIMES LCLS : Linac...

4

Linac Coherent Light SourCe  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Linac Linac Coherent Light SourCe after the Stanford Linear Accelerator Center (now the SLAC National Accelerator Laboratory) developed its two- mile-long linear accelerator (linac), it received approval from the Department of Energy to construct the Linac Coherent Light Source (LCLS), the first free electron laser (FEL) facility that would be able to produce x-rays short and bright enough that individual molecules could be imaged in their natural states. 40 years Genesis of the idea In 1992, Dr. Claudio Pellegrini, a professor at UCLA, first developed a proposal for a facility that would eventually become LCLS. The idea generated interest within the scientific community, and a design study report conducted by SLAC in the late 1990s led to the first

5

EA-1904: Linac Coherent Light Source II at Stanford Linear Accelerator  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

4: Linac Coherent Light Source II at Stanford Linear 4: Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, California EA-1904: Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, California Summary This EA evaluates the environmental impacts of the proposed construction of the Linac Coherent Light Source at SLAC National Accelerator Laboratory, Menlo Park, California. Public Comment Opportunities 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 Electronic mail: dave.osugi@sso.science.doe.gov Documents Available for Download March 7, 2012 EA-1904: Finding of No Significant Impact Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, CA

6

EA-1904: Linac Coherent Light Source II at Stanford Linear Accelerator  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

04: Linac Coherent Light Source II at Stanford Linear 04: Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, California EA-1904: Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, California Summary This EA evaluates the environmental impacts of the proposed construction of the Linac Coherent Light Source at SLAC National Accelerator Laboratory, Menlo Park, California. Public Comment Opportunities 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 Electronic mail: dave.osugi@sso.science.doe.gov Documents Available for Download March 7, 2012 EA-1904: Finding of No Significant Impact Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, CA

7

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

NLE Websites -- All DOE Office Websites (Extended Search)

Science and Instrumentation for the Linac Coherent Light Source WB00852.GIF (317 bytes) Where: SLAC Panofsky Auditorium When: Friday, October 15, 1999 (1:30 pm) Saturday,...

8

IMPACT simulation and the SNS linac beam  

E-Print Network (OSTI)

dynamics studies of the SNS linac systems were performedIMPACT SIMULATION AND THE SNS LINAC BEAM * Y. Zhang 1 , J.tracking simulations for the SNS linac beam dynamics studies

Zhang, Y.

2009-01-01T23:59:59.000Z

9

The Linac Coherent Light Source is  

NLE Websites -- All DOE Office Websites (Extended Search)

Coherent Light Source is Coherent Light Source is a revolution in x-ray science. Just as the invention of x-ray machines a century ago astonishingly revealed the inside of our bodies and began new sciences, the world's first x-ray laser will open up unprecedented opportunities. Pioneering experiments will advance our understand ing of everything from the hidden physics inside planets, to how proteins function as the engines of life, to building nanotechnology devices for the backbone of future industry and technology. The applications are legion: medicine, electronics, biology, solid-state physics, nanotechnology, energy production, industry and fields that do not yet exist. Linac Coherent Light Source New Tools Create New Science The LCLS is dramatically different from any x-ray

10

SLAC Linac Coherent Light Source User Site  

NLE Websites -- All DOE Office Websites (Extended Search)

Welcome to the LCLS User Resources Site Welcome to the LCLS User Resources Site User Portal | Agreements | Data Collection & Analysis | Logistics | Policies | Proposals | Safety | Schedules | Shipping The Linac Coherent Light Source (LCLS) encourages scientists from diverse fields to submit proposals for experiments that utilize the LCLS's unique capabilities. Interested scientists are encouraged to learn more about the latest developments by contacting LCLS staff scientists and by reviewing the instrument descriptions. Step-By-Step Instructions to Working at LCLS Review LCLS Policies Review Machine FAQ & Parameters Register and Submit Proposals Confirm User Agreement Reserve Accommodations Complete Safety Training Request Computer Account Establish User Account Ship Samples/Equipment Review Check-in Procedures

11

Linac Coherent Light Source Overview | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Linac Coherent Light Source Overview Linac Coherent Light Source Overview Linac Coherent Light Source Overview Addthis Description 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. Duration 5:50 Topic Physics Credit Energy Department Video MR. : The SLAC National Accelerator Laboratory is located in the heart of California's beautiful San Francisco Bay Area. Operated by Stanford University for the U.S. Department of Energy, SLAC has been home to the world's longest particle accelerator for nearly 50 years. In 2009 SLAC ushered in a new era in its long history of physics research with a new kind of laser called the Linac Coherent Light Source, or LCLS. The LCLS is the first laser in the world to produce hard X-rays, which can

12

Short-pulse limits in optical instrumentation design for the SLAC Linac Cohereent Light Source (LCLS)  

E-Print Network (OSTI)

Short-pulse limits in optical instrumentation design for the SLAC Linac Cohereent Light Source (LCLS)

Tatchyn, R

1999-01-01T23:59:59.000Z

13

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

U.S. Department of Energy (DOE) U.S. Department of Energy (DOE) Finding of No Significant Impact Construction and Operation of the Linac Coherent Light Source (LCLS) at the Stanford Linear Accelerator Center (SLAC), California. AGENCY: U.S. Department of Energy (DOE) ACTION: Finding of No Significant Impact (FONSI) SUMMARY: The U.S. Department of Energy (DOE) has prepared an Environmental Assessment (EA), DOE/EA-1426, evaluating the proposed action to construct and operate the Linac Coherent Light Source (LCLS) at the Stanford Linear Accelerator Center (SLAC). Based upon the information and analyses in the EA, the DOE has determined that the proposed federal action does not significantly affect the quality of the human environment within the meaning of the National Environmental Policy Act of 1969.

14

SLAC National Accelerator Laboratory - Linac Coherent Light Source...  

NLE Websites -- All DOE Office Websites (Extended Search)

LCLS - Linac Coherent Light Source Banner image of LCLS undulator hall. LCLS, the world's first hard X-ray free-electron laser, pushes science to new extremes with ultrabright,...

15

Linac Coherent Light Source Video and Multimedia Collection  

DOE Data Explorer (OSTI)

The Linac Coherent Light Source (LCLS), a DOE Scientific User Facility, began operation in 2009. SLAC's two-mile-long linear accelerator (linac) has long produced high-energy electrons for physics experiments. Now the linac is driving a new kind of laser, creating X-ray pulses more than a billion times brighter than the most powerful existing sources. Intense x-ray beams are not new. However, atoms are constantly moving or vibrating, and synchrotron X-ray sources produce long pulses which yield only blurred images of these motions. LCLS is the first source to produce X-rays that are both very intense and clumped into ultrafast pulses. By sequencing together images of the ultrasmall, taken with the ultrafast pulses of the LCLS, scientists are for the first time creating molecular movies, revealing the frenetic action of the atomic world for us to see. [Extracted, with edits, from http://lcls.slac.stanford.edu/WhatIsLCLS_1.aspx] The LCLS Multimedia gallery currently includes four short videos about the science and several clips that provide animated tours or flyovers of the facility and its instruments. Podcasts are an opportunity to hear key staff members address details of LCLS operations, and blog entries from five team members provide behind-the-scenes glimpses of this physics adventure.

16

An Overview of near-field vs. far-field radiation characteristics of the Linac Coherent Light Sources (LCLS)  

E-Print Network (OSTI)

An Overview of near-field vs. far-field radiation characteristics of the Linac Coherent Light Sources (LCLS)

Tatchyn, R

2005-01-01T23:59:59.000Z

17

Alternate Tunings for the Linac Coherent Light Source Photoinjector  

SciTech Connect

The Linac Coherent Light Source (LCLS) is an x-ray free-electron laser (FEL) project based on the SLAC linac. The LCLS Photoinjector beamline has been designed to deliver 10-ps long electron bunches of 1 nC with a normalized projected transverse emittance smaller than 1.2 mm-mrad at 135 MeV. Tolerances and regulation requirements are tight for this tuning. Half of the total emittance at the end of the injector comes from the ''cathode emittance'' which is 0.7 mm-mrad for our nominal 1nC tuning. As the ''cathode emittance'' scales linearly with laser spot radius, the emittance will be dramatically reduced for smaller radius, but this is only possible at lower charge. In particular, for a 0.2 nC charge, we believe we can achieve an emittance closer to 0.4 mm-mrad. This working point will be easier to tune and the beam quality should be much easier to maintain than for the 1 nC case. In the second half of this paper, we discuss optimum laser pulse shapes. We demonstrate that the benefits of the ellipsoidal shapes seem to be important enough so that serious investigations should be carried out in the production of such pulses.

Limborg-Deprey, C.; Emma, P.; /SLAC

2006-03-17T23:59:59.000Z

18

Beam-based Feedback for the Linac Coherent Light Source  

SciTech Connect

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

19

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

Science Conference Proceedings (OSTI)

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

Boutet, Sebastien

2011-08-16T23:59:59.000Z

20

Environmental Assessment for Linac Coherent Light Source Experimental Facility (12/02)  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Stanford Stanford Linear A ccelerator Center DOE/EA-1426 Environmental Assessment for Linac Coherent Light Source Experimental Facility LCLS December 2002 LCLS Environmental Assessment DOE/EA-1426 December 2002 Page - i - Environmental Assessment for LCLS Experimental Facility Table of Contents Preface ............................................................................................................................................ iii 1.0 Summary ................................................................................................................................... 1 2.0 Purpose and Need for LCLS ..................................................................................................... 6 3.0 Description of Proposed Action and Alternatives

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

Michelson interferometer design for Linac Coherent Light Source (LCLS) applications in the 15 Anstrom to 1.5 Anstrom wavelength range  

E-Print Network (OSTI)

Michelson interferometer design for Linac Coherent Light Source (LCLS) applications in the 15 Anstrom to 1.5 Anstrom wavelength range

Tatchy, R

1999-01-01T23:59:59.000Z

22

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

Science Conference Proceedings (OSTI)

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

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

2009-05-20T23:59:59.000Z

23

Robust CsBr/Cu Photocathodes for the Linac Coherent Light Source  

Science Conference Proceedings (OSTI)

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

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

2011-06-21T23:59:59.000Z

24

The Linac Coherent Light Source at SLAC. Radiological Considerations and Shielding calculations  

Science Conference Proceedings (OSTI)

The Linac Coherent Light Source (LCLS) at SLAC will be the world's first X-ray free electron laser when it becomes operational in 2009. Pulses of X-ray laser light from LCLS will be many orders of magnitude brighter and several orders of magnitude shorter than what can be produced by other X-ray sources available in the world. These characteristics will enable frontier new science in many areas. This paper describes the LCLS beam parameters and its lay-out. Results of the Monte Carlo calculations for the shielding design of the electron dump line, radiation damage to undulator, the residual radiation and the soil activation around the electron dump are presented.

Mao, X.S.; Fasso, A.; Nakao, N.; Rokni, S.H.; Vincke, H.; /SLAC

2005-12-02T23:59:59.000Z

25

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

Science Conference Proceedings (OSTI)

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

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

2012-01-01T23:59:59.000Z

26

EA-1426: Finding of No Significant Impact | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

of No Significant Impact EA-1426: Finding of No Significant Impact Linac Coherent Light Source Project, Stanford Linear Accelerator Center, Menlo Park, California The DOE...

27

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

No Significant Impact EA-1904: Finding of No Significant Impact Linac Coherent Light Source II at Stanford Linear Accelerator Laboratory, San Mateo, CA Based on the findings in...

28

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

SciTech Connect

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

29

Prospects for high power Linac Coherent Light Source (LCLS) development in the 1000{angstrom} {minus} 1{angstrom} wavelength range  

Science Conference Proceedings (OSTI)

Electron bunch requirements for single-pass saturation of a Free-Electron Laser (FEL) operating at full transverse coherence in the Self-Amplified Spontaneous Emission (SASE) mode include: (1) a high peak current, (2) a sufficiently low relative energy spread, and (3) a transverse emittance {var_epsilon}[r-m] satisfying the condition {var_epsilon} {le} {lambda}A/4{pi}, where {lambda}[m] is the output wavelength of the FEL. In the insertion device that induces the coherent amplification, the prepared electron bunch must be kept on a trajectory sufficiently collinear with the amplified photons without significant dilution of its transverse density. In this paper we discuss a Linac Coherent Light Source (LCLS) based on a high energy accelerator such as, e.g., the 3km S-band structure at the Stanford Linear Accelerator Center (SLAC), followed by a long high-precision undulator with superimposed quadrupole (FODO) focusing, to fulfill the given requirements for SASE operation in the 1000{Angstrom}--1{Angstrom} range. The electron source for the linac, an RF gun with a laser-excited photocathode featuring a normalized emittance in the 1--3 mm-mrad range, a longitudinal bunch duration of the order of 3 ps, and approximately 10{sup {minus}9} C/bunch, is a primary determinant of the required low transverse and longitudinal emittances. Acceleration of the injected bunch to energies in the 5--25 GeV range is used to reduce the relative longitudinal energy spread in the bunch, as well as to reduce the transverse emittance to values consistent with the cited wavelength regime. Two longitudinal compression stages are employed to increase the peak bunch current to the 2--5 kA levels required for sufficiently rapid saturation. The output radiation is delivered, via a grazing-incidence mirror bank, to optical instrumentation and a multi-user beam line system. Technological requirements for LCLS operation at 40{Angstrom}, 4.5{Angstrom}, and 1.5{Angstrom} are examined.

Tatchyn, R.; Bane, K.; Boyce, R. [and others

1994-03-01T23:59:59.000Z

30

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

SciTech Connect

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

31

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

Science Conference Proceedings (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

32

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

Science Conference Proceedings (OSTI)

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

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

2012-04-15T23:59:59.000Z

33

Progressing UK Energy Research for a Coherent Structure with Impact  

E-Print Network (OSTI)

the deployment of affordable green energy technologies that decarbonise our energy supply and increase energy with their collaborators in industry who are so vital to the health of UK Energy research, for rising to the challengesProgressing UK Energy Research for a Coherent Structure with Impact Report of the International

Berzins, M.

34

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

Science Conference Proceedings (OSTI)

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

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

2012-03-19T23:59:59.000Z

35

SLAC Linac Coherent Light Source  

NLE Websites -- All DOE Office Websites (Extended Search)

Science User Facility Search this site... Search Help (new window) Top Link Bar LCLS Lasers Expand Lasers LCLS Quick Launch Home About LCLS Expand About LCLS LCLS News Expand...

36

SAC - Linac Coherent Light Source  

NLE Websites -- All DOE Office Websites (Extended Search)

| Contact Us | Visitor Information User Resources LUSI Cost & Schedule Glossary News LCLS SAC LCLS FAC LCLS Science LCLS Machine FEL Resources Stanford University logo Stanford...

37

Linac Energy Management for LCLS  

SciTech Connect

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

38

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

DOE Green Energy (OSTI)

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

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

2005-08-01T23:59:59.000Z

39

SLAC Linac RF Performance for LCLS *  

E-Print Network (OSTI)

The Linac Coherent Light Source (LCLS) project at SLAC uses a dense 15 GeV electron beam passing through a long undulator to generate extremely bright x-rays at 1.5 angstroms. The project requires electron bunches with a nominal peak current of 3.5kA and bunch lengths of 0.020mm (70fs). The bunch compression techniques used to achieve the high brightness impose challenging tolerances on the accelerator RF phase and amplitude. The results of measurements on the existing SLAC linac RF phase and amplitude stability are summarised and improvements needed to meet the LCLS tolerances are discussed. 1 LCLS RF REQUIREMENTS LCLS requires the SLAC linac to perform with tolerances on RF phase and amplitude stability which are beyond all previous requirements. The LCLS is divided into four linacs L0, L1, L2, and L3 [1]. The phase and amplitude tolerances for the four linacs operated at S-

unknown authors

2000-01-01T23:59:59.000Z

40

THE IMPACT OF FREQUENCY STANDARDS ON COHERENCE IN VLBI AT THE HIGHEST FREQUENCIES  

SciTech Connect

We have carried out full imaging simulation studies to explore the impact of frequency standards in millimeter and submillimeter very long baseline interferometry (VLBI), focusing on the coherence time and sensitivity. In particular, we compare the performance of the H-maser, traditionally used in VLBI, to that of ultra-stable cryocooled sapphire oscillators over a range of observing frequencies, weather conditions, and analysis strategies. Our simulations show that at the highest frequencies, the losses induced by H-maser instabilities are comparable to those from high-quality tropospheric conditions. We find significant benefits in replacing H-masers with cryocooled sapphire oscillator based frequency references in VLBI observations at frequencies above 175 GHz in sites which have the best weather conditions; at 350 GHz we estimate a 20%-40% increase in sensitivity over that obtained when the sites have H-masers, for coherence losses of 20%-10%, respectively. Maximum benefits are to be expected by using co-located Water Vapor Radiometers for atmospheric correction. In this case, we estimate a 60%-120% increase in sensitivity over the H-maser at 350 GHz.

Rioja, M.; Dodson, R. [ICRAR, University of Western Australia, Perth (Australia); Asaki, Y. [Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Chuou, Sagamihara, Kanagawa 252-5210 (Japan); Hartnett, J. [School of Physics, University of Western Australia, Perth (Australia); Tingay, S., E-mail: maria.rioja@icrar.org [ICRAR, Curtin University, Perth (Australia)

2012-10-01T23:59:59.000Z

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.


41

SLAC Linac Coherent Light Source User Site  

NLE Websites -- All DOE Office Websites (Extended Search)

User Logistics User Logistics Accommodations/Hours/Maps | Agreements | Check-In | Computing | Safety | Shipping | Supplies & Gases | User Feedback | Publications Proposal Submission and Scheduling Step-By-Step Instructions to Working at LCLS Review LCLS Policies Review Machine FAQ & Parameters Register and Submit Proposals Confirm User Agreement Reserve Accommodations Complete Safety Training Request Computer Account Establish User Account Ship Samples/Equipment Review Check-in Procedures Provide Feedback Inform us of Publications Participate in LCLS Users' Organization LCLS experiments start with submitting a proposal, usually due twice a year. Each proposal is for one specific experiment and each proposal is valid for one scheduling cycle only. There is no limit to the number of

42

SLAC Linac Coherent Light Source User Site  

NLE Websites -- All DOE Office Websites (Extended Search)

Safety Safety Safety and Security Overview | Proposal Safety Review | Safety Training | Feedback Safety and Security Overview Step-By-Step Instructions to Working at LCLS Review LCLS Policies Review Machine FAQ & Parameters Register and Submit Proposals Confirm User Agreement Reserve Accommodations Complete Safety Training Request Computer Account Establish User Account Ship Samples/Equipment Review Check-in Procedures Provide Feedback Inform us of Publications Participate in LCLS Users' Organization Each person who works at LCLS is required to be familiar with and identify in advance the hazards associated with his/her work, the hazards associated with work areas, and to properly implement all necessary procedures and protocols for mitigation of those hazards. Each person is required to

43

SLAC Linac Coherent Light Source User Site  

NLE Websites -- All DOE Office Websites (Extended Search)

Accommodations / Hours / Maps 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 access, a fitness center, a 24-hour reception desk, laundry facilities, free parking, complimentary tea and coffee, and a 24-hour gift shop. The Guest House offers single as well as shared rooms, but all rooms have their own bathroom, and at very reasonable rates. All rooms are non-smoking only. Please reserve accommodations using their on-line form. If the Guest House is not available, additional accommodations may be made at local hotels/motels. For longer term visits, please contact the User Research Administration office. Gate Hours Maps & Directions SLAC Maps Directions to SLAC Security Gate 17

44

SLAC Linac Coherent Light Source User Site  

NLE Websites -- All DOE Office Websites (Extended Search)

LCLS User Check-In Procedures LCLS User Check-In Procedures All users must check in at the User Research Administration (URA) offices upon arrival. Users must complete relevant training and return all forms to User Research Administration, Building 120, Room 211, prior to going to the LCLS Near Experimental Hall (NEH) or starting any experiments. The URA office is staffed Monday-Friday from 8 am to 4 pm. Many steps can and should be completed prior to your arrival: Automated access is now in operation 24/7 at Gate 17 and the Sector 30 Gate. Avoid delays by contacting us before arriving. If you have current safety training and an activated proximity card, your card will open the automated gate. Proceed to User Research Administration (URA) in Building 120 for check-in. However, you will need to first stop at SLAC Security IF you are a

45

SLAC Linac Coherent Light Source User Site  

NLE Websites -- All DOE Office Websites (Extended Search)

(SAC) LCLS Detector Advisory Committee (LDAC) LCLS Proposal Review Panel LCLS Users' Organization LCLS Collaborators User Research Administration Floor Support Staff Letter...

46

SLAC Linac Coherent Light Source User Site  

NLE Websites -- All DOE Office Websites (Extended Search)

Schedules Machine Status Machine FAQ Safety Organization Committees and Contacts Organization Structure Collaborators Directories LCLS Directory SLAC Directory Stanford...

47

SLAC Linac Coherent Light Source User Site  

NLE Websites -- All DOE Office Websites (Extended Search)

X-ray Scattering, Spectroscopy, or Single Particle Imaging of Biological Objects (BIO-S);Chemistry and Materials-Soft Condensed Matter (CHEMSCM); Materials-Hard Condense...

48

SLAC Linac Coherent Light Source User Site  

NLE Websites -- All DOE Office Websites (Extended Search)

Christian Bressler European XFEL (2011-2014), Chair ChemistrySoft Condensed Matter (CHEM) Petra Fromme Arizona State University (2013-2016) Biology (BIO)Atomic, Molecular and...

49

Bioimaging Workshop - Linac Coherent Light Source  

NLE Websites -- All DOE Office Websites (Extended Search)

| Contact Us | Visitor Information User Resources LUSI Cost & Schedule Glossary News LCLS SAC LCLS FAC LCLS Science LCLS Machine FEL Resources Stanford University logo Stanford...

50

SLAC Linac Coherent Light Source User Site  

NLE Websites -- All DOE Office Websites (Extended Search)

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

51

SLAC Linac Coherent Light Source User Site  

NLE Websites -- All DOE Office Websites (Extended Search)

650-926-3191 | Fax: 650-926-3600 We encourage your comments, questions or suggestions. LCLSSLAC is located on 426 acres of Stanford University property, just three miles west of...

52

SLAC Linac Coherent Light Source User Site  

NLE Websites -- All DOE Office Websites (Extended Search)

Policies and Guidelines Access | Installation of User-Supplied Endstations | Reporting and Acknowledgement | Publications and Press | Proposal Preparation | Proposal Review| Beam...

53

SLAC Linac Coherent Light Source User Site  

NLE Websites -- All DOE Office Websites (Extended Search)

Schedules Schedules Schedule of Experiments for the Current Run | User Support Requests | Changes to the Operating Schedule LCLS Operations Schedules Step-By-Step Instructions to Working at LCLS Review LCLS Policies Review Machine FAQ & Parameters Register at User Portal Confirm User Agreement Reserve Accommodations Complete Safety Training Request Computer Account Establish User Account Ship Samples/Equipment Review Check-in Procedures Provide Feedback Inform us of Publications Participate in LCLS Users' Organization Tentative Long-Range Operating Plans Experiments Scheduled March to August 2014 Experiments Scheduled July 2013 to March 2014 Experiments Scheduled January to July 2013 Experiments Scheduled June to December 2012 Experiments Scheduled November 2011 to May 2012

54

Magnet innovations for linacs  

Science Conference Proceedings (OSTI)

It is possible to produce large magnetic fields at the aperture of permanent magnet quadrupoles, even when the magnetic aperture is very small. That, combined with their compactness, makes permanent magnet quadrupoles very powerful components of small aperture linacs. Results will be presented about past and present work on both fixed and variable strength permanent magnets suitable for use in and around linacs.

Halbach, K.

1986-06-01T23:59:59.000Z

55

LLRF System Upgrade for the SLAC Linac  

SciTech Connect

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

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

2012-07-06T23:59:59.000Z

56

Coherent Modes of Global SST and Summer Rainfall over China: An Assessment of the Regional Impacts of the 1997–98 El Niño  

Science Conference Proceedings (OSTI)

In this paper, the authors have identified three coherent modes of summertime rainfall variability over China and global sea surface temperature (SST) for the period of 1955–98 by Singular Value Decomposition. Based on these modes, the impacts of ...

K-M. Lau; Hengyi Weng

2001-03-01T23:59:59.000Z

57

Identifying Longitudinal Jitter Sources in the LCLS Linac  

Science Conference Proceedings (OSTI)

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

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

2012-07-06T23:59:59.000Z

58

NSLS Booster & Linac Ring  

NLE Websites -- All DOE Office Websites (Extended Search)

Booster & Linac Ring Booster & Linac Ring Booster Operating Parameters (pdf) Lattice Information (pdf) Mechanical Drawing (pdf) Standard Operating Mode Electrons are injected into the NSLS storage rings from a 750 MeV booster synchrotron fed by a 120 MeV linac. The electrons are first produced in a 100 KeV triode electron gun. The gun is pulsed at the booster revolution period, 94.6 nsec, seven times per booster cycle. Each pulse is 5 nsec long and supplies about 17 microbunches in the linac. After acceleration in the linac, the beam is injected into the booster on seven successive turns. Multi-turn injection in the booster is accomplished in the following way: The beam is deflected into the booster by a septum magnet. The first linac pulse goes around the booster and returns to the injection point just as

59

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

60

BEAM STUDIES AT THE SNS LINAC  

Science Conference Proceedings (OSTI)

The most recent beam dynamics studies at the Spallation Neutron Source (SNS) linac, including major beam loss reduction efforts in the normal conducting linac and in the superconducting linac (SCL), and the simulation and measurement of longitudinal beam halo and longitudinal acceptance at the entrance of the SCL are discussed. Oscillation of the beam centroid around the linac synchronous phase and the phase adiabatic damping curves in the SNS linac are investigated with linac longitudinal models and measured with all the linac beam phase monitors.

Zhang, Yan [ORNL

2009-01-01T23:59:59.000Z

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.


61

BNL | S-band Linac  

NLE Websites -- All DOE Office Websites (Extended Search)

S-band Linac S-band Linac Some experiments at the ATF require higher energies than what is available from the photoinjector. We use two traveling wave linac structures, known as 'SLAC sections' (from the famous 2-mile SLAC linac). Each section provides an acceleration given by: Energy gain (in MeV) = 10.8*SQRT(Power in MW)-39.5*Current(in amps) The current to be used is an equivalent steady state current. The microwave drive power, at a frequency of 2856 MHz, is provided by a single XK5 klystron tube (the old SLAC klystron). This tube can provide up to 25 MW. The ATF modulator can provide the XK5 klystron with high voltage for about 3 microseconds. This 3 microsecond pulse is called the macropulse. The repetition rate for the macropulses is from 1 to 6 per second. Within each

62

Induction Linac Pulsers  

DOE Green Energy (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

63

Beam Loss Studies for Rare Isotope Driver Linacs Final Report  

Science Conference Proceedings (OSTI)

The Fortran 90 RIAPMTQ/IMPACT code package is a pair of linked beam-dynamics simulation codes that have been developed for end-to-end computer simulations of multiple-charge-state heavy-ion linacs for future exotic-beam facilities. These codes have multiple charge-state capability, and include space-charge forces. The simulations can extend from the low-energy beam-transport line after an ECR ion source to the end of the linac. The work has been performed by a collaboration including LANL, LBNL, ANL, and MSU. The code RIAPMTQ simulates the linac front-end beam dynamics including the LEBT, RFQ, and MEBT. The code IMPACT simulates the beam dynamics of the main superconducting linac. The codes have been benchmarked for rms beam properties against previously existing codes at ANL and MSU. The codes allow high-statistics runs on parallel supercomputing platforms, particularly at NERSC at LBNL, for studies of beam losses. The codes also run on desktop PC computers for low-statistics work. The code package is described in more detail in a recent publication [1] in the Proceedings of PAC07 (2007 US Particle Accelerator Conference). In this report we describe the main activities for the FY07 beam-loss studies project using this code package.

Wangler, T P; Kurennoy, S S; Billen, J H; Crandall, K R; Qiang, J; Ryne, R D; Mustapha, B; Ostroumov, P; Zhao, Q; York, and R. C.

2008-03-26T23:59:59.000Z

64

Electron Linacs for High Energy Physics  

Science Conference Proceedings (OSTI)

The purpose of this article is to introduce some of the basic physical principles underlying the operation of electron linear accelerators (electron linacs). Electron linacs have applications ranging from linacs with an energy of a few MeV, such that the electrons are approximately relativistic, to future electron-positron linear colliders having a collision energy in the several-TeV energy range. For the most part, only the main accelerating linac is treated in this article.

Wilson, Perry B.; /SLAC

2011-11-08T23:59:59.000Z

65

Intrabeam stripping in H- Linacs  

Science Conference Proceedings (OSTI)

A beam loss in the superconducting part of the SNS linac has been observed during its commissioning and operation. Although the loss does not prevent the SNS high power operation, it results in an almost uniform irradiation of linac components and increased radiation levels in the tunnel. Multi-particle tracking could neither account for the magnitude of the observed loss nor its dependence on machine parameters. It was recently found that the loss is consistent with the intrabeam particle collisions resulting in stripping of H{sup -} ions. The paper describes experimental observations and corresponding analytical estimates of the intrabeam stripping.

Lebedev, V.; Solyak, N.; Ostigy, J.-F.; /Fermilab; Alexandrov, A.; Shishlo, A.; /Oak Ridge

2010-09-01T23:59:59.000Z

66

EA-1087: Proposed Induction Linac System Experiments in Building 51B at  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

7: Proposed Induction Linac System Experiments in Building 7: Proposed Induction Linac System Experiments in Building 51B at Lawrence Berkeley National Laboratory, Berkeley, California EA-1087: Proposed Induction Linac System Experiments in Building 51B at Lawrence Berkeley National Laboratory, Berkeley, California SUMMARY 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 on a new Induction Linear Accelerator System. PUBLIC COMMENT OPPORTUNITIES None available at this time. DOCUMENTS AVAILABLE FOR DOWNLOAD September 8, 1995 EA-1087: Finding of No Significant Impact Proposed Induction Linac System Experiments in Building 51B at Lawrence Berkeley National Laboratory, Berkeley, California

67

Linac Coherent Light Source Overview | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Energy 101: Solar PV Sec. Chu Online Town Hall Energy 101: Cool Roofs Energy 101: Geothermal Heat Pumps Why Cool Roofs? Chu at COP-16: Building a Sustainable Energy Future...

68

Linac Coherent Light Source Overview | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Pledge? Conversation on the Future of the Wind Industry Science Lecture: Talking the Higgs Boson with Dr. Joseph Incandela Bill Gates and Deputy Secretary Poneman Discuss the...

69

Linac Coherent Light Source Overview | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Kill-a-Watt Competition at University of Central Florida Faces of the Recovery Act: Sun Catalytix Investing in Clean, Safe Nuclear Energy Secretary Chu Speaks at the 2010...

70

Linac Coherent Light Source Overview | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

BP Oil Spill Footage (High Def) - Leak at 4850' - June 3 2010 (2 of 4) BP Oil Spill Footage (High Def) - Leak at 4840' - June 3 2010 (1 of 4) Re-Building Greensburg The...

71

Linac Coherent Light Source Overview | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Weatherizing Wilkes-Barre White House Science Fair Recap Energy 101: Home Energy Assessment Recovery Act update from Sr. Advisor Matt Rogers -- End of Obligations The Recovery Act...

72

Linac Coherent Light Source Overview | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Cathy Zoi on Weatherization BP Oil Spill Footage (High Def) - Top Hat Procedure at 4850' - June 3 2010 (4 of 4) BP Oil Spill Footage (High Def) - Leak at 4850' - June 3 2010 (3 of...

73

Linac Coherent Light Source Overview | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Energy 101: Energy Efficient Data Centers Energy 101: Daylighting Solar Smarter Faster Seven Traffic Signals in Two Minutes It Starts with Science... Demoing the Modified TALON...

74

Linac Coherent Light Source Overview | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

The Future of Biofuels The Climate Challenge... and What's at Stake Sec. Chu Announces the First Auto Loans for Advanced Technologies...

75

Linac Coherent Light Source Overview | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Security & Safety -Emergency Response & Procedures or Search Energy.gov Search Clear Filters All Videos ARPA-E 2011 Keynote: Dr. Arun Majumdar ARPA-E 2011 Keynote: Ray Mabus,...

76

Compiler Analysis for Cache Coherence: Interprocedural Array Data-Flow Analysis and Its Impact on Cache Performance  

Science Conference Proceedings (OSTI)

Abstract¿In this paper, we present compiler algorithms for detecting references to stale data in shared-memory multiprocessors. The algorithm consists of two key analysis techniques, stale reference detection and locality preserving analysis. While the ... Keywords: Compiler, interprocedural analysis, data-flow analysis, cache coherence, shared-memory multiprocessors.

Lynn Choi; Pen-Chung Yew

2000-09-01T23:59:59.000Z

77

BEAM DYNAMICS ISSUES IN THE SNS LINAC  

Science Conference Proceedings (OSTI)

A review of the Spallation Neutron Source (SNS) linac beam dynamics is presented. It describes transverse and longitudinal beam optics, losses, activation, and comparison between the initial design and the existing accelerator. The SNS linac consists of normal conducting and superconducting parts. The peculiarities in operations with the superconducting part of the SNS linac (SCL), estimations of total losses in SCL, the possible mechanisms of these losses, and the progress in the transverse matching are discussed.

Shishlo, Andrei P [ORNL

2011-01-01T23:59:59.000Z

78

Electron Linac Offers Safe, Affordable Production Method for ...  

Biomass and Biofuels; Building Energy Efficiency; ... The electron beam in Linac 2 is also transmitted through the same target then collected in Linac 1 to accelerate ...

79

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

Science Conference Proceedings (OSTI)

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

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

2011-12-13T23:59:59.000Z

80

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

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.


81

Impact of Explicit Atmosphere–Ocean Coupling on MJO-Like Coherent Structures in Idealized Aquaplanet Simulations  

Science Conference Proceedings (OSTI)

This paper discusses the impact of the atmosphere–ocean coupling on the large-scale organization of tropical convection simulated by an idealized global model applying the Cloud-Resolving Convection Parameterization (CRCP; superparameterization). ...

Wojciech W. Grabowski

2006-09-01T23:59:59.000Z

82

A recirculating linac-based facility for ultrafast X-ray science  

SciTech Connect

We present an updated design for a proposed source of ultra-fast synchrotron radiation pulses based on a recirculating superconducting linac, in particular the incorporation of EUV and soft x-ray production. The project has been named LUX - Linac-based Ultrafast X-ray facility. The source produces intense x-ray pulses with duration of 10-100 fs at a 10 kHz repetition rate, with synchronization of 10 s fs, optimized for the study of ultra-fast dynamics. The photon range covers the EUV to hard x-ray spectrum by use of seeded harmonic generation in undulators, and a specialized technique for ultra-short-pulse photon production in the 1-10 keV range. High-brightness rf photocathodes produce electron bunches which are optimized either for coherent emission in free-electron lasers, or to provide a large x/y emittance ration and small vertical emittance which allows for manipulation to produce short-pulse hard x-rays. An injector linac accelerates the beam to 120 MeV, and is followed by four passes through a 600-720 MeV recirculating linac. We outline the major technical components of the proposed facility.

Corlett, J.N; Barletta, W.A.; DeSantis, S.; Doolittle, L.; Fawley, W.M.; Green, M.A.; Heimann, P.; Leone, S.; Lidia, S.; Li, D.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wolski, A.; Zholents, A.; Placidi, M.; Pirkl, W.; Parmigiani, F.

2003-05-06T23:59:59.000Z

83

Design features of high-intensity medium-energy superconducting heavy-ion Linac.  

DOE Green Energy (OSTI)

The proposed Rare Isotope Accelerator (RIA) requires the construction of a cw 1.4 GV superconducting (SC) linac that is capable of producing 400 kW beams of all ions from protons at 900 MeV to uranium at 400 MeV/u. The design of such a linac was outlined at the previous Linac conference. This linac will accelerate multiple-charge-states (multi-q) of the heaviest ion beams, for which the beam current is limited by ion-source performance. The linac consists of two different types of accelerating and focusing lattice: for uranium below {approx}85 MeV/u the focusing is provided by SC solenoids installed in cryostats with the SC resonators while in the high-beta section the focusing elements are located outside of the cryostats. A detailed design has been developed for the focusing-accelerating lattice of the linac. Beam dynamics studies have been performed with the goal of optimization of the linac structure in order to reduce a possible effective emittance growth of the multi-q uranium beam. A wide tuning range of the accelerating and focusing fields is required for acceleration of the variety of ions with different charge-to-mass ratios to the highest possible energy in single charge state mode. The focusing must be retuned for different ion masses to avoid resonance coupling between the transverse and longitudinal motions. Any visible impact of this coupling on the formation of beam halo must be avoided due to the high beam power.

Ostroumov, P. N.

2002-09-20T23:59:59.000Z

84

New Post-Linac Collimation System  

NLE Websites -- All DOE Office Websites (Extended Search)

Post-Linac Post-Linac Collimation System for the Next Linear Collider NLC Post-Linac Collimation Task Force LCC-Note-0052 21-Feb-2001 Abstract We present a new design for the NLC post-linac collimation system. The new design sepa- rates the collimation of off-energy particles and particles with large betatron amplitudes. The energy collimation system achieves passive protection against damage by an errant bunch train via large horizontal dispersion and vertical betatron functions, and makes use of optical symme- tries to reduce jitter amplification. The betatron collimation system permits infrequent damage to the thin "spoiler" collimators, while the thick "absorber" collimators have a much larger aperture and are thus more difficult to hit. The physical phenomena which are relevant to the design and operation of the collimation system are reviewed, and

85

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.

Billen, James H. (Los Alamos, NM)

1996-01-01T23:59:59.000Z

86

BEAM TRANSVERSE ISSUES AT THE SNS LINAC  

Science Conference Proceedings (OSTI)

The Spallation Neutron Source (SNS) linac system is designed to deliver 1 GeV pulsed H- beams up to 1.56 MW. As beam power was increased from 10 kW to 680 kW in less than three years, beam loss in the accelerator systems C particularly in the superconducting linac (SCL), became more critical. In the previous studies, beam loss in the SCL was mainly attributed to longitudinal problems. However, our most recent simulations have focused on the transverse issues. These include multipole components from magnet imperfections and from dipole corrector windings of the SNS linac quadrupoles. The effects of these multipoles coupled with other transverse errors and a new possible cause of beam loss will be discussed.

Zhang, Yan [ORNL; Allen, Christopher K [ORNL; Holmes, Jeffrey A [ORNL; Galambos, John D [ORNL; Wang, Jian-Guang [ORNL

2010-01-01T23:59:59.000Z

87

S-Band Loads for SLAC Linac  

SciTech Connect

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

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

2012-08-28T23:59:59.000Z

88

A Stability of LCLS Linac Modulators  

SciTech Connect

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

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

2012-06-13T23:59:59.000Z

89

An “NLC-Style ” Short Bunch Length Compressor in the SLAC Linac*  

E-Print Network (OSTI)

Experimental tests of a “second bunch length compressor” in a linac is important for the next generation of linear colliders and for other future accelerators. These future accelerators need bunches with lengths of order 0.06- 0.2 mni. At these lengths, new accelerator dynamics will be encountered. We have studied the possibility of constructing a second compressor with the present SLAC linac and have found a reasonable design’. The core of this project is to recontigure an old beamline (BL-90) at the 1OOOm location in the linac to: (1) extract a 10 GeV bunch, (2) pass it through a new 96 m long transport line in which length compression is done, and (3) reinject the beam into the main linac in an available drift section. Using the resulting compressed bunch, accelerator physics tests would be performed in the remaining downstream linac with the resulting very high charge density. The bunch compression in this transport line results Erom ExWiq BASlWBL90 aipor the TRANSPORT element R56 as determined from the optics of the transport line. AZ = R56 AEJE. For example, if AZ =.-0.5 mm, AIYE = OS%, R56 =-0.1 m, a bunch of 5 x lOlo particles would have a final length (03 of about 0.08 mm with apeakcurrentof96OOA. II. Decription of the Project This project would use as much existing SLAC equipment as possible: including the SLC accelerator complex, old SPEAR injection line magnets, spare power supplies and diagnostics. No civil construction is required. The design is aimed at a rapid construction and installation schedule, maintaining flexibility and with no operational impact on other SLAC programs: SLC, FFTB, or B-Factory. A schematic layout of the bunch compressor is shown in Fig. 1. The basic beam parameters are listed in Table 1. The

John T. Seeman; John T. Seeman

1993-01-01T23:59:59.000Z

90

Bunch Shape Monitor for SSCL linac  

SciTech Connect

The Superconducting Super Collider Laboratory and the Institute for Nuclear Research ore collaboratively developing a Bunch Shape Monitor diagnostics for commission the SSCL linac. The Bunch Shape Monitor is designed to measure the intensity of beam as a function of time over the micro-bunch of the beam. Design resolution for the SSCL monitors is approximately 7 psec. The first monitor will operate at the fundamental frequency of 428 MHz and will be used to measure the output beam of the RFQ Linac. First available results will be presented and compared with predictions. Further development will allow the monitors to fit in a standard SSCL beam box and one will operate at the third harmonic of 428 MHz. Proposals to use the Bunch Shape Monitor to measure the longitudinal phase space distribution of the beam will be discussed.

Hurd, J.W.; Arbique, G.M.; Crist, C.E.; Guy, F.W.; Leifeste, G.T.; Raparia, D.; Saadatmand, K.; Swenson, D.A. [Superconducting Super Collider Lab., Dallas, TX (United States); Esin, S.; Feschenko, A.; Stepanov, A.; Mirzojan, A. [AN SSSR, Moscow (Russian Federation). Inst. Yadernykh Issledovanij

1993-05-01T23:59:59.000Z

91

HIGH CURRENT ENERGY RECOVERY LINAC AT BNL.  

SciTech Connect

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

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

2005-05-16T23:59:59.000Z

92

Analysis on linac quadrupole misalignment in FACET commissioning 2012  

Science Conference Proceedings (OSTI)

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

Sun, Yipeng; /SLAC

2012-07-05T23:59:59.000Z

93

Emittance Measurement and Modeling of the ALS 50 MeV Linac to Booster Line  

E-Print Network (OSTI)

Measurement and Modeling of the ALS 50 Me V Linac to Boosterhave been measured for the ALS LINAC through non-linear X2Measurement and Modeling of the ALS 50 Me V Linac to Booster

Bengtsson, J.

2011-01-01T23:59:59.000Z

94

Superconducting radiofrequency linac development at Fermilab  

SciTech Connect

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

95

An overview of LINAC ion sources  

SciTech Connect

This paper discusses ion sources used in high-duty-factor proton and H{sup -} Linacs as well as in accelerators utilizing multi-charged heavy ions, mostly for nuclear physics applications. The included types are Electron Cyclotron Resonance (ECR) sources as well as filament and rf driven multicusp sources. The paper does not strive to attain encyclopedic character but rather to highlight major lines of development, peak performance parameters and type-specific limitations and problems of these sources. The main technical aspects being discussed are particle feed, plasma generation and ion production by discharges, and plasma confinement.

Keller, Roderich [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

96

SNS LINAC MODULATOR OPERATIONAL HISTORY AND PERFOMANCE  

Science Conference Proceedings (OSTI)

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

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

2011-01-01T23:59:59.000Z

97

PHYSICS RESULTS OF THE NSLS-II LINAC FRONT END TEST STAND  

Science Conference Proceedings (OSTI)

The Linac Front End Test Stand (LFETS) was installed at the Source Development Laboratory (SDL) in the fall of 2011 in order to test the Linac Front End. The goal of these tests was to test the electron source against the specifications of the linac. In this report, we discuss the results of these measurements and the effect on linac performance.

Fliller R. P.; Gao, F.; Yang, X.; Rose, J.; Shaftan, T.; Piel, C

2012-05-20T23:59:59.000Z

98

RF and Beam Diagnostic Instrumentation at the Advanced Photon Source (APS) Linear Accelerator (Linac)  

E-Print Network (OSTI)

RF and Beam Diagnostic Instrumentation at the Advanced Photon Source (APS) Linear Accelerator (Linac)

Grelick, A E; Arnold, N; White, M

1996-01-01T23:59:59.000Z

99

PERFORMANCE OF THE DIAGNOSTICS FOR NSLS-II LINAC COMMISSIONING  

Science Conference Proceedings (OSTI)

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

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

2011-03-28T23:59:59.000Z

100

High-Performance Beam Simulator for the LANSCE Linac  

SciTech Connect

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

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

2012-05-14T23:59:59.000Z

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

TRANSVERSE MATCHING PROGRESS OF THE SNS SUPERCONDUCTING LINAC  

Science Conference Proceedings (OSTI)

Experience using laser-wire beam profile measurement to perform transverse beam matching in the SNS superconducting linac is discussed. As the SNS beam power is ramped up to 1 MW, transverse beam matching becomes a concern to control beam loss and residual activation in the linac. In our experiments, however, beam loss is not very sensitive to the matching condition. In addition, we have encountered difficulties in performing a satisfactory transverse matching with the envelope model currently available in the XAL software framework. Offline data analysis from multi-particle tracking simulation shows that the accuracy of the current online model may not be sufficient for modeling the SC linac.

Zhang, Yan [ORNL; Cousineau, Sarah M [ORNL; Liu, Yun [ORNL

2011-01-01T23:59:59.000Z

102

A Program for Optimizing SRF Linac Costs  

Science Conference Proceedings (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

103

Coherence-Enhanced Lasing  

E-Print Network (OSTI)

Quantum coherence and interference effects in atomic and molecular physics has been extensively studied due to intriguing counterintuitive physics and potential important applications. In this paper we studied one such scenario of using quantum coherence to generate and enhanced gain in extreme ultra-violet(XUV)(@58.4nm in Helium) and infra-red(@794.76nm in Rubidium) regime of electromagnetic radiation. We show that using moderate external coherent drive, a substantial enhancement in the energy of the lasing pulse can be achieved under optimal conditions. The role of coherence is also discussed here.

Jha, Pankaj K

2013-01-01T23:59:59.000Z

104

Generation of Coherent X-Ray Radiation through Modulation Compression  

Science Conference Proceedings (OSTI)

In this paper, we propose a scheme to generate tunable coherent X-ray radiation for future light source applications. This scheme uses an energy chirped electron beam, a laser modulator, 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} in 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 attoseconds pulse, 1 nm coherent X-ray radiation using a 60 A 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; /LBL, Berkeley; Wu, Juhao; /SLAC

2012-06-12T23:59:59.000Z

105

Energy Spread Compensation for Multi-Bunch Linac Operation Mode  

NLE Websites -- All DOE Office Websites (Extended Search)

ENERGY SPREAD COMPENSATION FOR MULTI-BUNCH LINAC OPERATION MODE D. Mihalcea, Northern Illinois University, DeKalb, IL 60115, USA W. Gai, J. G. Power, ANL, Argonne, IL 60439, USA...

106

High Power Superconducting Continuous Wave Linacs for Protons...  

Office of Science (SC) Website

(ANL) Developed in: Current Result of NP research: Spin-off of high power driver linac R&D for the FRIB project Application currently being supported by: DOE Office of Nuclear...

107

EBIS as an injector for heavy-ion linacs  

SciTech Connect

The Electron Beam Ion Source (EBIS), because of its high-charge states and pulsed operation, is ideally suited as an injector for a heavy-ion linac operating at a low duty factor. Although presently in use with conventional linacs, the low emittance and the large yield of highly charged ions in each pulse make the EBIS even more interesting as an injector for the new linac accelerating structures such as the alternating-phase-focusing (APF) structure or the radio-frequency quadrupole (RFQ) structure. These new structures could be used with an EBIS to produce a small, efficient, low-duty-cycle accelerator. Coupled to a conventional linac, the resulting accelerator could be used for heavy-ion medical therapy or nuclear physics, or it could be used as an injector for a synchrotron or storage ring.

Hamm, R.W.

1979-01-01T23:59:59.000Z

108

Compensation of Beam Loading in the ALS Injector Linac  

E-Print Network (OSTI)

to offset the beam loading. ALS Injector Requirements Gun.gun, bunchers, and 50 MeV linac of the ALS injection system.The ALS injector design has been described in previous

Selph, F.

1988-01-01T23:59:59.000Z

109

Geophysical Applications of Partial Wavelet Coherence and Multiple Wavelet Coherence  

Science Conference Proceedings (OSTI)

In this paper, the application of partial wavelet coherence (PWC) and multiple wavelet coherence (MWC) to geophysics is demonstrated. PWC is a technique similar to partial correlation that helps identify the resulting wavelet coherence (WTC) ...

Eric K. W. Ng; Johnny C. L. Chan

2012-12-01T23:59:59.000Z

110

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

SciTech Connect

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

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

2009-01-15T23:59:59.000Z

111

Design Optimization for an X-Ray Free Electron Laser Driven by SLAC Linac  

E-Print Network (OSTI)

FREE ELECTRON LASER DRIVEN BY SLAC LINAC Ming Xie, LawrenceLaser (FEL) driven by the SLAC linac. The study assumes theis carried out for the SLAC FEL over all independent system

Xie, Ming

1994-01-01T23:59:59.000Z

112

High Power Superconducting Continuous Wave Linacs for Protons and  

Office of Science (SC) Website

Power Superconducting Continuous Power Superconducting Continuous Wave Linacs for Protons and Heavy-Ions Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Spinoff Applications Spinoff Archives SBIR/STTR Applications of Nuclear Science and Technology Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: sc.np@science.doe.gov More Information » Spinoff Archives High Power Superconducting Continuous Wave Linacs for Protons and Heavy-Ions Print Text Size: A A A RSS Feeds FeedbackShare Page Application/instrumentation: High Power Superconducting Continuous Wave Linacs for Protons and Heavy-Ions

113

DIAGNOSTIC TOOLS FOR BEAM HALO INVESTIGATION IN SNS LINAC  

Science Conference Proceedings (OSTI)

Uncontrolled beam loss is a major concern in the operation of a high intensity hadron linac. A low density cloud of particles with large oscillation amplitudes, so called halo, can form around the dense regular beam core. This halo can be a direct or indirect cause of beam loss. There is experimental evidence of halo growing in the SNS linac and limiting the further reduction of beam loss. A set of tools is being developed for detecting of the halo and investigating its origin and dynamics. The set includes high resolution emittance measurements in the injector, laser based emittance measurements at 1 GeV, and high resolution profile measurements along the linac. We will present our experience with useful measurement techniques and data analysis algorithms.

Aleksandrov, Alexander V [ORNL; Blokland, Willem [ORNL; Liu, Yun [ORNL; Long, Cary D [ORNL; Zhukov, Alexander P [ORNL

2012-01-01T23:59:59.000Z

114

Overview and status of RF systems for the SSC Linac  

SciTech Connect

The Superconducting Super Collider (SSC) Linear Accelerator (Linac) produces a 600-MeV, 35-{mu}s, H-beam at a 10-Hz repetition rate. The beam is accelerated by a series of RF cavities. These consist of a Radio Frequency Quadrupole (RFQ), two bunchers, and four Drift Tube Linac (DTL) tanks at 427.617 MHz, and two bunchers, nine side-coupled Linac modules, and an energy compressor at 1282.851 MHz. The RFQ amplifier and the low-frequency buncher cavity amplifiers use gridded tubes, while the other cavities use klystron amplifier systems. The RF control system consists of a reference line and cavity feedback and feedforward loops for each amplifier. The RF amplifier system for each of these accelerator cavities is described, and the current status of each system is presented.

Mynk, J.; Grippe, J.; Cutler, R.I.; Rodriguez, R.

1993-05-01T23:59:59.000Z

115

LINAC BEAM DYNAMICS SIMULATIONS WITH PY-ORBIT  

Science Conference Proceedings (OSTI)

Linac dynamics simulation capabilities of the PyORBIT code are discussed. PyORBIT is an open source code and a further development of the original ORBIT code that was created and used for design, studies, and commissioning of the SNS ring. The PyORBIT code, like the original one, has a two-layer structure. C++ is used to perform time-consuming computations, and the program flow is controlled from a Python language shell. The flexible structure makes it possible to use PyORBIT also for linac dynamics simulations. A benchmark of PyORBIT with Parmila and the XAL Online model is presented.

Shishlo, Andrei P [ORNL

2012-01-01T23:59:59.000Z

116

BEAM SIMULATIONS USING VIRTUAL DIAGNOSTICS FOR THE DRIVER LINAC  

Science Conference Proceedings (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

117

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

Science Conference Proceedings (OSTI)

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

Ratner, Daniel; /Stanford U. /SLAC

2012-05-25T23:59:59.000Z

118

Critical design issues of high intensity proton linacs  

SciTech Connect

Medium-energy proton linear accelerators are being studied as drivers for spallation applications requiring large amounts of beam powder. Important design factors for such high-intensity linacs are reviewed, and issues and concerns specific to this unprecedented power regime are discussed.

Lawrence, G.P.

1994-08-01T23:59:59.000Z

119

Status of Hybrid Target R&D at KEK LINAC  

E-Print Network (OSTI)

A hybrid positron source, consisting of a crystal as electron to photon converter and a amorphous target, is a candidate to relax heat load problem for high intensity positron sources. In this article we report status of experimental study using the 8 GeV electron beam at KEKB LINAC.

Tohru Takahashi

2012-02-27T23:59:59.000Z

120

Intensity Effects of the FACET Beam in the SLAC Linac  

SciTech Connect

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

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

2012-07-03T23:59:59.000Z

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

Coherent Inc | Open Energy Information  

Open Energy Info (EERE)

Coherent Inc Jump to: navigation, search Name Coherent Inc Place Santa Clara, California Zip 95054 Sector Solar Product US-based manufacturer of photonics-based equipments such as...

122

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

123

Constrainted Coherent States  

E-Print Network (OSTI)

Coherent states possess a regularized path integral and gives a natural relation between classical variables and quantum operators. Recent work by Klauder and Whiting has included extended variables, that can be thought of as gauge fields, into this formalism. In this paper, I consider the next step, and look at the roll of first class constraints.

M. C. Ashworth

1996-04-21T23:59:59.000Z

124

Coherent Radiation in Insertion Devices  

E-Print Network (OSTI)

We calculate the coherent radiation in an undulator/wiggler with a vacuum chamber of arbitrary cross section. The backward radiation is a coherent and it has wavelengths about twice the period of the undulator/wiggler. Mostly of coherent radiation is going with the wavelengths approximately the bunch length at small angles however.

Mikhailichenko, A A

2011-01-01T23:59:59.000Z

125

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

SciTech Connect

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

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

2012-05-20T23:59:59.000Z

126

H- AND PROTON BEAM LOSS COMPARISON AT SNS SUPERCONDUCTING LINAC  

Science Conference Proceedings (OSTI)

A comparison of beam loss in the superconducting part (SCL) of the Spallation Neutron Source (SNS) linac for H- and protons is presented. During the experiment the nominal beam of negative hydrogen ions in the SCL was replaced by a proton beam created by insertion of a thin stripping carbon foil placed in the low energy section of the linac. The observed significant reduction in the beam loss for protons is explained by a domination of the intra beam stripping mechanism of the beam loss for H-. The details of the experiment are discussed, and a preliminary estimation of the cross section of the reaction H- + H- -> H- + H0 + e is presented. Earlier, a short description of these studies was presented in [1].

Aleksandrov, Alexander V [ORNL; Galambos, John D [ORNL; Plum, Michael A [ORNL; Shishlo, Andrei P [ORNL

2012-01-01T23:59:59.000Z

127

The Linac Injector For The ANL 7 Ge V Advanced Photon Source  

NLE Websites -- All DOE Office Websites (Extended Search)

Injector For The ANL 7 Ge V Injector For The ANL 7 Ge V Advanced Photon Source A. Nassiri, W. Wesolowski, and G. Mavrogenes Argonne National Laboratory Submitted to the 1990 LINAC Conferece Albuquerque, New Mexico LS-154 9/28/90 TEE LINAC INJECTOR FOR TEE ANL 7 G<.iJ,V ADVANCED PHOTON SOORCE* A. Nassiri, W. Wesolowski, and G. Mavrogenes Argonne National Laboratory 9700 South Cass Avenue Argonne, IL 60439 USA Abstract The Argonne Advanced Photon Source (APS) linac system consists of a 200 MeV electron linac, a positron converter, and a 450 MeV positron linac. Design parameters and computer simulations of the two linac systems are presented. Introduction The Argonne Advanced Photon Source is a 7 GeV synchrotron X-Ray facility. The APS machine parameters have been described.

128

BEAM POSITION AND PHASE MONITORS FOR THE LANSCE LINAC  

SciTech Connect

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

McCrady, Rodney C. [Los Alamos National Laboratory; Gilpatrick, John D. [Los Alamos National Laboratory; Power, John F. [AOT-IC

2011-01-01T23:59:59.000Z

129

HIGH DYNAMIC-RANGE HIGH SPEED LINAC CURRENT MEASUREMENTS  

SciTech Connect

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; Curry, Douglas E [ORNL; Dickson, Richard W [ORNL

2012-01-01T23:59:59.000Z

130

BEAM POSITION AND PHASE MONITORS FOR THE LANSCE LINAC  

Science Conference Proceedings (OSTI)

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

McCrady, Rodney C. [Los Alamos National Laboratory; Gilpatrick, John D. [Los Alamos National Laboratory; Watkins, Heath A. [Los Alamos National Laboratory

2012-04-11T23:59:59.000Z

131

Experimental studies of multipass beam breakup and energy recovery using the CEBAF injector linac.  

E-Print Network (OSTI)

??Beam breakup (BBU) instabilities in superconducting linacs are a significant issue due to the potentially high Q of the cavity higher-order modes (HOMs). The CEBAF… (more)

Sereno, Nicholas S. R.

1994-01-01T23:59:59.000Z

132

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 Spinoff Applications Spinoff Archives SBIRSTTR...

133

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 Spinoff Applications Spinoff Archives SBIRSTTR...

134

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

135

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

136

HINS Linac front end focusing system R&D  

SciTech Connect

This report summarizes current status of an R&D program to develop a focusing system for the front end of a superconducting RF linac. Superconducting solenoids will be used as focusing lenses in the low energy accelerating sections of the front end. The development of focusing lenses for the first accelerating section is in the production stage, and lens certification activities are in preparation at FNAL. The report contains information about the focusing lens design and performance, including solenoid, dipole corrector, and power leads, and about cryogenic system design and performance. It also describes the lens magnetic axis position measurement technique and discusses scope of an acceptance/certification process.

Apollinari, G.; Carcagno, R.H.; Dimarco, J.; Huang, Y.; Kashikhin, V.V.; Orris, D.F.; Page, T.M.; Rabehl, R.; Sylvester, C.; Tartaglia, M.A.; Terechkine, I.; /Fermilab /Argonne

2008-08-01T23:59:59.000Z

137

Induction Linac Systems Experiments for heavy ion fusion  

Science Conference Proceedings (OSTI)

The Lawrence Berkeley Laboratory and the Lawrence Livermore National Laboratory propose to build at LBL the Induction Linac Systems Experiments (ILSE), the next logical step toward the eventual goal of a heavy ion induction accelerator powerful enough to implode or drive inertial confinement fusion targets. Though much smaller than a driver, ILSE will be at full driver scale in several important parameters. Nearly all accelerator components and beam manipulations required for a driver will be tested. It is expected that ILSE will be built in stages as funds and technical progress allow. The first stage, called Elise will include all of the electrostatic quadrupole focused parts of ILSE.

Herrmannsfeldt, W.B. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Bangerter, R.O. [Lawrence Berkeley Lab., CA (United States). Accelerator and Fusion Research Div.

1994-06-01T23:59:59.000Z

138

AMPERE AVERAGE CURRENT PHOTOINJECTOR AND ENERGY RECOVERY LINAC.  

SciTech Connect

High-power Free-Electron Lasers were made possible by advances in superconducting linac operated in an energy-recovery mode. In order to get to much higher power levels, say a fraction of a megawatt average power, many technological barriers are yet to be broken. We describe work on CW, high-current and high-brightness electron beams. This will include a description of a superconducting, laser-photocathode RF gun employing a new secondary-emission multiplying cathode, an accelerator cavity, both capable of producing of the order of one ampere average current and plans for an ERL based on these units.

BEN-ZVI,I.; BURRILL,A.; CALAGA,R.; ET AL.

2004-08-17T23:59:59.000Z

139

Coherent Orthogonal Polynomials  

E-Print Network (OSTI)

We discuss as a fundamental characteristic of orthogonal polynomials like the existence of a Lie algebra behind them, can be added to their other relevant aspects. At the basis of the complete framework for orthogonal polynomials we put thus --in addition to differential equations, recurrence relations, Hilbert spaces and square integrable functions-- Lie algebra theory. We start here from the square integrable functions on the open connected subset of the real line whose bases are related to orthogonal polynomials. All these one-dimensional continuous spaces allow, besides the standard uncountable basis ${|x>}$, for an alternative countable basis ${|n>}$. The matrix elements that relate these two bases are essentially the orthogonal polynomials: Hermite polynomials for the line and Laguerre and Legendre polynomials for the half-line and the line interval, respectively. Differential recurrence relations of orthogonal polynomials allow us to realize that they determine a unitary representation of a non-compact Lie algebra, whose second order Casimir ${\\cal C}$ gives rise to the second order differential equation that defines the corresponding family of orthogonal polynomials. Thus, the Weyl-Heisenberg algebra $h(1)$ with ${\\cal C}=0$ for Hermite polynomials and $su(1,1)$ with ${\\cal C}=-1/4$ for Laguerre and Legendre polynomials are obtained. Starting from the orthogonal polynomials the Lie algebra is extended both to the whole space of the ${\\cal L}^2$ functions and to the corresponding Universal Enveloping Algebra and transformation group. Generalized coherent states from each vector in the space ${\\cal L}^2$ and, in particular, generalized coherent polynomials are thus obtained.

E Celeghini; Mariano A del Olmo

2012-05-29T23:59:59.000Z

140

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

SciTech Connect

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

Sun, Yipeng; Adolphsen, Chris; /SLAC

2011-08-19T23:59:59.000Z

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.


141

Transient Quantum Coherent Response to a Partially Coherent Radiation Field  

E-Print Network (OSTI)

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

Z. S. Sadeq; Paul Brumer

2013-12-10T23:59:59.000Z

142

Quantum-Bayesian Coherence  

E-Print Network (OSTI)

In a quantum-Bayesian take on quantum mechanics, the Born Rule cannot be interpreted as a rule for setting measurement-outcome probabilities from an objective quantum state. But if not, what is the role of the rule? In this paper, we argue that it should be seen as an empirical addition to Bayesian reasoning itself. Particularly, we show how to view the Born Rule as a normative rule in addition to usual Dutch-book coherence. It is a rule that takes into account how one should assign probabilities to the consequences of various intended measurements on a physical system, but explicitly in terms of prior probabilities for and conditional probabilities consequent upon the imagined outcomes of a special counterfactual reference measurement. This interpretation is seen particularly clearly by representing quantum states in terms of probabilities for the outcomes of a fixed, fiducial symmetric informationally complete (SIC) measurement. We further explore the extent to which the general form of the new normative rule implies the full state-space structure of quantum mechanics. It seems to get quite far.

Christopher A. Fuchs; Ruediger Schack

2009-06-11T23:59:59.000Z

143

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

144

Covariant Closed String Coherent States  

Science Conference Proceedings (OSTI)

We give the first construction of covariant coherent closed string states, which may be identified with fundamental cosmic strings. We outline the requirements for a string state to describe a cosmic string, and provide an explicit and simple map that relates three different descriptions: classical strings, light cone gauge quantum states, and covariant vertex operators. The resulting coherent state vertex operators have a classical interpretation and are in one-to-one correspondence with arbitrary classical closed string loops.

Hindmarsh, Mark; Skliros, Dimitri [Department of Physics and Astronomy, University of Sussex, Brighton, East Sussex BN1 9QH (United Kingdom)

2011-02-25T23:59:59.000Z

145

Measurement-based Coherency Identification and Aggregation for Power Systems  

SciTech Connect

In power system model reduction, a high reduction ratio is often desired to handle much more complex power systems. The bottleneck of traditional methods lies in: ? Coherency identification methods are conservative. Some coherency generators are not detected when system topology or operating points change, because coherency identification depends on system topology or operating points. ?There are some solitary generators in external systems. These generators do not belong to any coherency group. However, sometimes these solitary generators have little impact on tie-line power flow, and it might be possible to ignore their dynamics in model reduction. But because they do not belong to any coherency group, existing reduction methods cannot handle them well. In order to overcome the first problem, a measurement-based online coherency identification method is presented in this paper. By analyzing post-fault trajectories measured by Phasor Measurement Units (PMUs), coherency generators are identified through principal component analysis. The method can track time-varying system topology and operating points. In order to address the second problem, this paper introduces sensitivity analysis into traditional reduction methods. The sensitivity of tie-line power flow against injected active power of external system generators is derived. Those generators having loose connection with tie-line power are identified through the sensitivity analysis, and their dynamics are ignored by replacing them with negative impedances. We test if the sensitivity, based on static power flow, provides good guidance to reduce the dynamic model. Case studies show that the proposed method can handle well these solitary generators and the reduction ratio can be enhanced through this method. Future work will include generalization of the sensitivity method.

Wang, Shaobu; Lu, Shuai; Lin, Guang; Zhou, Ning

2012-07-26T23:59:59.000Z

146

Energy recovery linacs in high-energy and nuclear physics  

Science Conference Proceedings (OSTI)

Energy Recovery Linacs (ERL) have significant potential uses in High Energy Physics and Nuclear Physics. We describe some of the potential applications which are under development by our laboratories in this area and the technology issues that are associated with these applications. The applications that we discuss are electron cooling of high-energy hadron beams and electron-nucleon colliders. The common issues for some of these applications are high currents of polarized electrons, high-charge and high-current electron beams and the associated issues of High-Order Modes. The advantages of ERLs for these applications are numerous and will be outlined in the text. It is worth noting that some of these advantages are the high-brightness of the ERL beams and their relative immunity to beam-beam disturbances.

I. Ben-Zvi; Ya. Derbenev; V. Litvinenko; L. Merminga

2005-03-01T23:59:59.000Z

147

EA-1087: Finding of No Significant Impact | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

87: Finding of No Significant Impact 87: Finding of No Significant Impact EA-1087: Finding of No Significant Impact Proposed Induction Linac System Experiments in Building 51B at Lawrence Berkeley National Laboratory, Berkeley, California Based on the information and analysis in the EA, DOE has determined that the proposal to construct and operate the Induction Linac System Experiments project does not constitute a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act of 1969. Therefore, a Finding of No Significant Impact is made and an Environmental Impact Statement is not required. EA-1087-FONSI-1995.pdf More Documents & Publications EA-1087: Final Environmental Assessment EA-1065: Finding of No Significant Impact

148

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

Office of Science (SC) Website

Energy Recovery Linac cavity at BNL Energy Recovery Linac cavity at BNL Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Spinoff Applications Spinoff Archives SBIR/STTR Applications of Nuclear Science and Technology Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: sc.np@science.doe.gov More Information » Spinoff Archives Energy Recovery Linac cavity at BNL Print Text Size: A A A RSS Feeds FeedbackShare Page Application/instrumentation: Energy Recovery Linac cavity Developed at: Brookhaven National Laboratory, New York and Advanced Energy Systems, New York Developed in:

149

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

Office of Science (SC) Website

High Current Energy Recovery Linac at High Current Energy Recovery Linac at BNL Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Spinoff Applications Spinoff Archives SBIR/STTR Applications of Nuclear Science and Technology Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: sc.np@science.doe.gov More Information » Spinoff Archives High Current Energy Recovery Linac at BNL Print Text Size: A A A RSS Feeds FeedbackShare Page Application/instrumentation: High Current Energy Recovery Linac Developed at: Brookhaven National Laboratory, New York and Advanced Energy Systems, New

150

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

SciTech Connect

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

151

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

SciTech Connect

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

152

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

SciTech Connect

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

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

2012-12-21T23:59:59.000Z

153

Design of the NSLS-II Linac Front End Test Stand  

SciTech Connect

The NSLS-II operational parameters place very stringent requirements on the injection system. Among these are the charge per bunch train at low emittance that is required from the linac along with the uniformity of the charge per bunch along the train. The NSLS-II linac is a 200 MeV linac produced by Research Instruments Gmbh. Part of the strategy for understanding to operation of the injectors is to test the front end of the linac prior to its installation in the facility. The linac front end consists of a 100 kV electron gun, 500 MHz subharmonic prebuncher, focusing solenoids and a suite of diagnostics. The diagnostics in the front end need to be supplemented with an additional suite of diagnostics to fully characterize the beam. In this paper we discuss the design of a test stand to measure the various properties of the beam generated from this section. In particular, the test stand will measure the charge, transverse emittance, energy, energy spread, and bunching performance of the linac front end under all operating conditions of the front end.

Fliller III, R.; Johanson, M.; Lucas, M.; Rose, J.; Shaftan, T.

2011-03-28T23:59:59.000Z

154

Coherent infrared imaging camera (CIRIC)  

SciTech Connect

New developments in 2-D, wide-bandwidth HgCdTe (MCT) and GaAs quantum-well infrared photodetectors (QWIP) coupled with Monolithic Microwave Integrated Circuit (MMIC) technology are now making focal plane array coherent infrared (IR) cameras viable. Unlike conventional IR cameras which provide only thermal data about a scene or target, a coherent camera based on optical heterodyne interferometry will also provide spectral and range information. Each pixel of the camera, consisting of a single photo-sensitive heterodyne mixer followed by an intermediate frequency amplifier and illuminated by a separate local oscillator beam, constitutes a complete optical heterodyne receiver. Applications of coherent IR cameras are numerous and include target surveillance, range detection, chemical plume evolution, monitoring stack plume emissions, and wind shear detection.

Hutchinson, D.P.; Simpson, M.L.; Bennett, C.A.; Richards, R.K.; Emery, M.S.; Crutcher, R.I.; Sitter, D.N. Jr.; Wachter, E.A.; Huston, M.A.

1995-07-01T23:59:59.000Z

155

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

Science Conference Proceedings (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; Doleans, Marc [ORNL; Kim, Sang-Ho [ORNL

2013-01-01T23:59:59.000Z

156

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

SciTech Connect

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

157

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

Science Conference Proceedings (OSTI)

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

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

2009-12-17T23:59:59.000Z

158

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

SciTech Connect

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

159

Unfolding linac photon spectra and incident electron energies from experimental transmission data, with direct independent validation  

SciTech Connect

Purpose: In a recent computational study, an improved physics-based approach was proposed for unfolding linac photon spectra and incident electron energies from transmission data. In this approach, energy differentiation is improved by simultaneously using transmission data for multiple attenuators and detectors, and the unfolding robustness is improved by using a four-parameter functional form to describe the photon spectrum. The purpose of the current study is to validate this approach experimentally, and to demonstrate its application on a typical clinical linac. Methods: The validation makes use of the recent transmission measurements performed on the Vickers research linac of National Research Council Canada. For this linac, the photon spectra were previously measured using a NaI detector, and the incident electron parameters are independently known. The transmission data are for eight beams in the range 10-30 MV using thick Be, Al and Pb bremsstrahlung targets. To demonstrate the approach on a typical clinical linac, new measurements are performed on an Elekta Precise linac for 6, 10 and 25 MV beams. The different experimental setups are modeled using EGSnrc, with the newly added photonuclear attenuation included. Results: For the validation on the research linac, the 95% confidence bounds of the unfolded spectra fall within the noise of the NaI data. The unfolded spectra agree with the EGSnrc spectra (calculated using independently known electron parameters) with RMS energy fluence deviations of 4.5%. The accuracy of unfolding the incident electron energy is shown to be {approx}3%. A transmission cutoff of only 10% is suitable for accurate unfolding, provided that the other components of the proposed approach are implemented. For the demonstration on a clinical linac, the unfolded incident electron energies and their 68% confidence bounds for the 6, 10 and 25 MV beams are 6.1 {+-} 0.1, 9.3 {+-} 0.1, and 19.3 {+-} 0.2 MeV, respectively. The unfolded spectra for the clinical linac agree with the EGSnrc spectra (calculated using the unfolded electron energies) with RMS energy fluence deviations of 3.7%. The corresponding measured and EGSnrc-calculated transmission data agree within 1.5%, where the typical transmission measurement uncertainty on the clinical linac is 0.4% (not including the uncertainties on the incident electron parameters). Conclusions: The approach proposed in an earlier study for unfolding photon spectra and incident electron energies from transmission data is accurate and practical for clinical use.

Ali, E. S. M.; McEwen, M. R.; Rogers, D. W. O. [Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6 (Canada); Ionizing Radiation Standards, Institute for National Measurement Standards, National Research Council, M-35 Montreal Road, Ottawa, Ontario K1A 0R5 (Canada); Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6 (Canada)

2012-11-15T23:59:59.000Z

160

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.

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161

Modeling coherence in ESOL learner texts  

Science Conference Proceedings (OSTI)

To date, few attempts have been made to develop new methods and validate existing ones for automatic evaluation of discourse coherence in the noisy domain of learner texts. We present the first systematic analysis of several methods for assessing coherence ...

Helen Yannakoudakis; Ted Briscoe

2012-06-01T23:59:59.000Z

162

Status of the plasma generator of the superconducting proton linac  

SciTech Connect

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

163

Proton Driver Linac for the Frankfurt Neutron Source  

SciTech Connect

The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) will deliver high neutron fluxes in the energy range of 1 to 500 keV. The Activation Mode provides a high averaged neutron flux created by a cw proton beam of up to 5 mA, while in the Compressor Mode intense neutron pulses of 1 ns length are formed with a repetition rate of up to 250 kHz. The Compressor Mode is well-suited for energy-dependent neutron capture measurements using the Time-of-Flight method in combination with a 4{pi} BaF{sub 2} detector array. The design of the proton driver linac for both operation modes is presented. This includes the volume type ion source, the ExB chopper located in the low energy section, the RFQ-IH combination for beam acceleration and the bunch compressor. Finally, the neutron production at the lithium-7 target and the resulting energy spectrum is described.

Wiesner, C.; Chau, L. P.; Dinter, H.; Droba, M.; Heilmann, M.; Joshi, N.; Maeder, D.; Metz, A.; Meusel, O.; Noll, D.; Podlech, H.; Ratzinger, U.; Reichau, H.; Schempp, A.; Schmidt, S.; Schweizer, W.; Volk, K.; Wagner, C. [Institut fuer Angewandte Physik, Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt/Main (Germany); Reifarth, R. [Institut fuer Angewandte Physik, Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt/Main (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); Mueller, I.

2010-08-04T23:59:59.000Z

164

LANSCE Drift Tube Linac Water Control System Refurbishment  

Science Conference Proceedings (OSTI)

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

Marroquin, Pilar S. [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

165

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

E-Print Network (OSTI)

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

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

2013-07-30T23:59:59.000Z

166

Advanced beam-dynamics simulation tools for the RIA driver linac,Part I: Low energy beam transport and radiofrequency quadrupole  

Science Conference Proceedings (OSTI)

Advanced Beam-Dynamics Simulation Tools for the RIA Driver Linac; Low Energy Beam Transport and Radiofrequency Quadrupole.

Wangler, Thomas P.; Crandall, Kenneth R.; Garnett, Robert W.; Gorelov, Dmitry; Ostroumov, Petr; Qiang, Ji; Ryne, Robert; York, Richard

2003-08-26T23:59:59.000Z

167

Coherent Communications, Imaging and Targeting  

SciTech Connect

Laboratory and field demonstration results obtained as part of the DARPA-sponsored Coherent Communications, Imaging and Targeting (CCIT) program are reviewed. The CCIT concept uses a Phase Conjugation Engine based on a quadrature receiver array, a hologram processor and a spatial light modulator (SLM) for high-speed, digital beam control. Progress on the enabling MEMS SLM, being developed by a consortium consisting of LLNL, academic institutions and small businesses, is presented.

Stappaerts, E; Baker, K; Gavel, D; Wilks, S; Olivier, S; Brase, J; Olivier, S; Brase, J

2003-10-03T23:59:59.000Z

168

Resonance Excitation of Longitudinal High Order Modes in Project X Linac  

SciTech Connect

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

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

2012-05-01T23:59:59.000Z

169

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

SciTech Connect

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

Towne N.; Rose J.

2011-09-30T23:59:59.000Z

170

A CONCEPTUAL 3-GEV LANSCE LINAC UPGRADE FOR ENHANCED PROTON RADIOGRAPHY  

Science Conference Proceedings (OSTI)

A conceptual design of a 3-GeV linac upgrade that would enable enhanced proton radiography at the Los Alamos Neutron Science Center (LANSCE) is presented. The upgrade is based on the use of superconducting accelerating cavities to increase the present LANSCE linac output energy from 800 MeV to 3 GeV. The LANSCE linac currently provides negative hydrogen ion (H{sup -}) and proton (H{sup +}) beams to several user facilities that support Isotope Production, NNSA Stockpile Stewardship, and Basic Energy Science programs. Required changes to the front-end, the accelerating structures, and to the RF systems to meet the new performance goals, and changes to the existing beam switchyard to maintain operations for a robust user program are also described.

Garnett, Robert W [Los Alamos National Laboratory; Rybarcyk, Lawrence J. [Los Alamos National Laboratory; Merrill, Frank E. [Los Alamos National Laboratory; O'Hara, James F. [Los Alamos National Laboratory; Rees, Daniel E. [Los Alamos National Laboratory; Walstrom, Peter L. [Los Alamos National Laboratory

2012-05-14T23:59:59.000Z

171

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

SciTech Connect

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

172

Measurements of H/sup 0/ and H/sup +/ ion yields during H/sup -/ acceleration in a 50-MeV linac  

DOE Green Energy (OSTI)

Unlike proton linacs where the only particles that can be transported are protons, an H/sup -/ linac can produce H/sup 0/ and protons by stripping off one or both electrons of H/sup -/ ions during acceleration. We have measured yields of these ions as a function of linac tank pressures.

Cho, Y.; Madsen, J.; Shin, S.A.; Stipp, V.

1981-01-01T23:59:59.000Z

173

High-Brightness Beams from a Light Source Injector The Advanced Photon Source Low-Energy Undulator Test Line Linac  

E-Print Network (OSTI)

The use of existing linacs, and in particular light source injectors, for free-electron laser (FEL) experiments is becoming more common due to the desire to test FELs at ever shorter wavelengths. The high-brightness, high-current beams required by high-gain FELs impose technical specifications that most existing linacs were not designed to meet. Moreover, the need for specialized diagnostics, especially shot-to-shot data acquisition, demands substantial modification and upgrade of conventional linacs. Improvements have been made to the Advanced Photon Source (APS) injector linac in order to produce and characterize high-brightness beams. Specifically, effort has been directed at generating beams suitable for use in the low-energy undulator test line (LEUTL) FEL in support of fourth-generation light source research. The enhancements to the linac technical and diagnostic capabilities that allowed for self-amplified spontaneous emission (SASE) operation of the FEL at 530 nm are described. Recent results, includi...

Travish, G; Borland, M; Hahne, M; Harkay, K C; Lewellen, J W; Lumpkin, Alex H; Milton, S V; Sereno, N S

2000-01-01T23:59:59.000Z

174

INCREASED UNDERSTANDING OF BEAM LOSSES FROM THE SNS LINAC PROTON EXPERIMENT  

Science Conference Proceedings (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; Shishlo, Andrei P [ORNL; Plum, Michael A [ORNL; Lebedev, Valerie [FNAL; Laface, Emanuele [ESS; Galambos, John D [ORNL

2013-01-01T23:59:59.000Z

175

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

176

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

177

Coherence delay augmented laser beam homogenizer  

SciTech Connect

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

178

Interferometric SAR coherence classification utility assessment  

SciTech Connect

The classification utility of a dual-antenna interferometric synthetic aperture radar (IFSAR) is explored by comparison of maximum likelihood classification results for synthetic aperture radar (SAR) intensity images and IPSAR intensity and coherence images. The addition of IFSAR coherence improves the overall classification accuracy for classes of trees, water, and fields. A threshold intensity-coherence classifier is also compared to the intensity-only classification results.

Yocky, D.A.

1998-03-01T23:59:59.000Z

179

Multiple quantum coherence in HYSCORE spectra  

Science Conference Proceedings (OSTI)

The implementation of matched pulses in two-dimensional electron spin echo envelope modulation experiments results in a drastic increase in intensity of peaks representing nuclear multiple quantum coherence. For a spin system consisting of one electron spin S= 1 2 and two nuclei with spin I= 1 2 the nuclear coherence created by the sequence (?/2)???(?/2) is calculated. The transfer amplitudes between different kinds of nuclear coherences of a microwave ? pulse are given. A new matched HYSCORE pulse sequence

Lorenz Liesum; Arthur Schweiger

2001-01-01T23:59:59.000Z

180

Coherent instabilities in random lasers  

SciTech Connect

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

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.


181

Coherent Control of Quantum Matter  

Science Conference Proceedings (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

2011-10-05T23:59:59.000Z

182

Reflective Coherent Spatial Light Modulator (RCSLM)  

Reflective Coherent Spatial Light Modulator (RCSLM) Note: The technology described above is an early stage opportunity. Licensing rights to this intellectual property may

183

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

Science Conference Proceedings (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

184

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

185

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

186

Novel linac structures for low-beta ions and for muons  

SciTech Connect

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

187

Benchmark of the IMPACT Code for High Intensity Beam Dynamics Simulation  

E-Print Network (OSTI)

of Beam Dynamics in the SNS Linac," Nuclear Instruments andto study beam dynamics in the SNS linac, the J-PARC linac

Qiang, J.; Ryne, R.D.

2008-01-01T23:59:59.000Z

188

INJECTORS H. Hayano and M. Ross, Chairmen Presentations H. Hayano, "Linac Beam Stability"  

NLE Websites -- All DOE Office Websites (Extended Search)

2 2 INJECTORS H. Hayano and M. Ross, Chairmen Presentations H. Hayano, "Linac Beam Stability" S. Takeda, "Injector Linac Performance" S. Kashiwagi, "ECS Performance" K. Kubo, "Lattice Diagnostic (Linear Optics and Beta-Match)" T. Naito, "Performance of SR Monitor" . . . H. Hayano, "Performance of Alignment Method" J. Urakawa, "Summary of Ring Circumference Issue (Including Wiggler Issue)" N. Terunuma, "Summary of Vacuum Chamber Design Including Ring Impedance" T. Okugi, "Performance of Orbit Measurement" J. Urakawa, "Summary of Emittance Tuning" T. Raubenheimer, "Parameters - Combined Session" D. Yeremian, "Bunching Stability" J. Turner, "Injector Linac Performance"

189

A coherence model based on syntactic patterns  

Science Conference Proceedings (OSTI)

We introduce a model of coherence which captures the intentional discourse structure in text. Our work is based on the hypothesis that syntax provides a proxy for the communicative goal of a sentence and therefore the sequence of sentences in a coherent ...

Annie Louis; Ani Nenkova

2012-07-01T23:59:59.000Z

190

Investigations of silica alcogel aging using coherent light  

NLE Websites -- All DOE Office Websites (Extended Search)

Investigations of silica alcogel aging using coherent light Title Investigations of silica alcogel aging using coherent light Publication Type Journal Article Year of Publication...

191

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

NLE Websites -- All DOE Office Websites (Extended Search)

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

192

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

NLE Websites -- All DOE Office Websites (Extended Search)

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

193

A GAP package for computation with coherent configurations  

Science Conference Proceedings (OSTI)

We present a GAP package for computing with Schurian coherent configurations and their representations. Keywords: GAP, GRAPE, association scheme, centralizer ring, coherent configuration, permutation group, sage, semidefinite programming

Dmitrii V. Pasechnik; Keshav Kini

2010-09-01T23:59:59.000Z

194

Design Construction and Test Results of a HTS Solenoid for Energy Recovery Linac  

NLE Websites -- All DOE Office Websites (Extended Search)

DESIGN CONSTRUCTION AND TEST RESULTS OF A HTS SOLENOID DESIGN CONSTRUCTION AND TEST RESULTS OF A HTS SOLENOID FOR ENERGY RECOVERY LINAC* R. Gupta # , M. Anerella, I. Ben-Zvi, G. Ganetis, D. Kayran, G. McIntyre, J. Muratore, S. Plate and W. Sampson, Brookhaven National Laboratory, Upton, NY, 11973 USA and M. Cole and D. Holmes, Advanced Energy Systems, Inc., Medord, NY, 11763 USA Abstract An innovative feature of the proposed Energy Recovery Linac (ERL) is the use of a solenoid made with High Temperature Superconductor (HTS) with the Superconducting RF cavity. The use of HTS allows solenoid to be placed in close proximity to the cavity and thus provides early focusing of the electron beam. In addition, cryogenic testing at ~77 K is simpler and cheaper than 4 K testing. This paper will present the

195

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

Science Conference Proceedings (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

196

Automated Operation of the APS LINAC using the Procedure Execution Manager  

E-Print Network (OSTI)

The Advanced Photon Source (APS) linear accelerator has two thermionic cathode rf guns and one photocathode rf gun. The thermionic guns are used primarily for APS operations while the photocathode gun is used as a free-electron laser (FEL) driver. With each gun requiring a different lattice and timing configuration, the need to change quickly between guns puts great demands on the accelerator operators. Using the Procedure Execution Manager (PEM), a software environment for managing automated procedures, we have made start-up and switch-over of the linac systems both easier and more reliable. The PEM is a graphical user interface written in Tcl/Tk that permits the user to invoke "machine procedures" and control their execution. It allows construction of procedures in a hierarchical, parallel fashion, which makes for efficient execution and development. In this paper, we discuss the features and advantages of the PEM environment as well the specifics of our procedures for the APS linac.

Soliday, R; Borland, M

2000-01-01T23:59:59.000Z

197

CLIC simulations from the start of the linac to the interaction point  

E-Print Network (OSTI)

Simulations for linear colliders are traditionally performed separately for the different sub-systems, like damping ring, bunch compressor, linac, and beam delivery. The beam properties are usually passed from one sub-system to the other via bunch charge, RMS transverse emittances, RMS bunch length, average energy and RMS energy spread. It is implicitly assumed that the detailed 6D correlations in the beam distribution are not relevant for the achievable luminosity. However, it has recently been shown that those correlations can have a strong effect on the beam-beam interaction. We present first results on CLIC simulations that integrate linac, beam delivery, and beam-beam interaction. These integrated simulations also allow a better simulation of time-dependent effects, like ground perturbations and interference between several beam-based feedbacks.

Schulte, Daniel; Blair, G A; D'Amico, T E; Leros, Nicolas; Redaelli, S; Risselada, Thys; Zimmermann, Frank

2002-01-01T23:59:59.000Z

198

Upgrading the Data Acquisition and Control System of the LANSCE LINAC  

SciTech Connect

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

Baros, Dolores [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

199

New high power 200 MHz RF system for the LANSCE drift tube linac  

SciTech Connect

The Los Alamos Neutron Science Center (LANSCE) linac provides an 800 MeV direct H{sup +} proton beam, and injects H{sup {minus}} to the upgraded proton storage ring for charge accumulation for the Short Pulse Spallation Source. Accelerating these interlaced beams requires high average power from the 201.25 MHz drift tube linac (DTL) RF system. Three power amplifiers have operated at up to three Megawatts with 12% duty factor. The total number of electron power tubes in the RF amplifiers and their modulators has been reduced from fifty-two to twenty-four. The plant continues to utilize the original design of a tetrode driving a super power triode. Further increases in the linac duty factor are limited, in part, by the maximum dissipation ratings of the triodes. A description of the system modifications proposed to overcome these limitations includes new power amplifiers using low-level RF modulation for tank field control. The first high power Diacrode{reg_sign} is being delivered and a new amplifier cavity is being designed. With only eight power tubes, the new system will deliver both peak power and high duty factor, with lower mains power and cooling requirements. The remaining components needed for the new RF system will be discussed.

Lyles, J.; Friedrichs, C.; Lynch, M.

1998-12-31T23:59:59.000Z

200

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

SciTech Connect

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

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

2012-07-02T23:59:59.000Z

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

X-ray Sources by Energy Recovered Linacs and Their Needed R&D  

Science Conference Proceedings (OSTI)

In this paper we review the current state of research on energy recovered linacs as drivers for future X-ray sources. For many types of user experiments, such sources may have substantial advantages compared to the workhorse sources of the present: high energy storage rings. Energy recovered linacs need to be improved beyond present experience in both energy and average current to support this application. To build an energy recovered linac based X-ray user facility presents many interesting challenges. We present summaries on the Research and Development (R&D) topics needed for full development of such a source, including the discussion at the Future Light Sources Workshop held in Gaithersburg, Maryland on September 15- 17, 2009. A #12;rst iteration of an R&D plan is presented that is founded on the notion of building a set of succeedingly larger test accelerators exploring cathode physics, high average current injector physics, and beam recirculation and beam energy recovery at high average current. Our basic conclusion is that a reviewable design of such a source can be developed after an R&D period of #12;ve to ten years.

Benson, Stephen; Douglas, David; Dowell, David; Hernandez-Garcia, Carlos; Kayran, D; Krafft, Geoffrey; Legg, Robert; Moog, E; Obina, T; Rimmer, Robert

2011-05-01T23:59:59.000Z

202

Beam dynamics studies in the driver LINAC pre-Stripper section of the RIA facility.  

SciTech Connect

The RIA facility driver linac consists of about 400 superconducting (SC) independently phased rf cavities. The linac is designed to accelerate simultaneously several-charge-state beams to generate as much as 400 kW of uranium beam power. The linac beam dynamics is most sensitive to the focusing and accelerating-structure parameters of the prestripper section, where the uranium beam is accelerated from 0.17 keV/u to 9.4 MeV/u. This section is designed to accept and accelerate 2 charge states (28 and 29) of uranium beam from an ECR ion source. The prestripper section must be designed to minimize the beam emittance distortion of this two-charge-state beam. In particular, the inter-cryostat spaces must be minimized and beam parameters near transitions of the accelerating and focusing lattices must be matched carefully. Several sources of possible effective emittance growth are considered in the design of the prestripper section and a tolerance budget is established. Numerical beam dynamics studies include realistic electric and magnetic 3-dimensional field distributions in the SC rf cavities and SC solenoids. Error effects in the longitudinal beam parameters are studied.

Lessner, E. S.; Ostroumov, P. N.

2003-07-10T23:59:59.000Z

203

Coherent Synoptic Disturbances in the Australian Monsoon  

Science Conference Proceedings (OSTI)

Coherent synoptic-scale weather systems within the Australian monsoon are identified and tracked in the isentropic potential vorticity (PV) field from the ECMWF Interim Reanalysis (ERA-Interim) dataset during the Southern Hemisphere summer. The ...

Gareth J. Berry; Michael J. Reeder; Christian Jakob

2012-12-01T23:59:59.000Z

204

Disentangling chat with local coherence models  

Science Conference Proceedings (OSTI)

We evaluate several popular models of local discourse coherence for domain and task generality by applying them to chat disentanglement. Using experiments on synthetic multiparty conversations, we show that most models transfer well from text to dialogue. ...

Micha Elsner; Eugene Charniak

2011-06-01T23:59:59.000Z

205

A Coherent Strategy for Qauntum Gravity  

E-Print Network (OSTI)

Affine quantum gravity, which differs notably from either string theory or loop quantum gravity, is briefly reviewed. Emphasis in this article is placed on the use of affine coherent states in this program.

John R. Klauder

2004-11-10T23:59:59.000Z

206

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

207

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

208

A toy model for Macroscopic Quantum Coherence  

E-Print Network (OSTI)

The present article deals with Macroscopic Quantum Coherence resorting only to basic quantum mechanics. A square double well is used to illustrate the Leggett-Caldeira oscillations. The effect of thermal-radiation on two-level systems is discussed to some extent. The concept of decoherence is introduced at an elementary level. Handles are deduced for the energy, temperature and time scales involved in Macroscopic Quantum Coherence.

R. Muñoz-Vega; José-Job J. Flores-Godoy; G. Fernández-Anaya; Encarnación Salinas-Hernández

2012-10-29T23:59:59.000Z

209

Insertion of coherence requests for debugging a multiprocessor  

DOE Patents (OSTI)

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

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

2010-02-23T23:59:59.000Z

210

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

SciTech Connect

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

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

2011-09-12T23:59:59.000Z

211

Coherent structures and aeolian saltation  

E-Print Network (OSTI)

Aeolian sand transport models, widely employed by coastal scientists and managers, assume temporal and spatial homogeneity within the saltation field. This research questions that assumption by demonstrating that the saltation field is event-driven, therefore indicating that the saltation field is not temporally steady. The findings from this research may explain a portion of the conclusions from previous studies that indicated inequalities between model-estimated and field-measured aeolian sand transport. The relationship between unsteadiness in a turbulent wind field and pulses in a sand transport field was investigated on a beach near Shoalhaven Heads, New South Wales, Australia. Microphone-based saltation sensors, “miniphones,” and thermal anemometers (both instruments constructed exclusively for this field experiment) were co-located (0.02 m separation on center) and deployed between 0.01 and 0.0225 m above the bed, and sampled at 6000 Hz. Average grain size at the field site was 0.30 mm. Five runs totaling 2050 seconds of wind and saltation data were analyzed. The continuous wavelet transform, using the Morlet wavelet base, was the principle method for analyzing the wind and saltation records. The cross continuous wavelet transform was used to analyze the wind and saltation time series concurrently. Wind, saltation, and cross events were discerned by selecting wavelet power coefficients between wavelet scales of 0.4 and 3.0 seconds and with coefficients exceeding the 95% confidence interval. Average event spacing was 6.10, 6.50, and 6.73 seconds for the wind, saltation, and cross events, respectively. The average event spacing measured in this research was compared to the empirical-based model presented by Rao, Narashimha, and Narayanan (1971). The correspondence between the model and this research strongly suggests that bursting-type coherent structures were present. The durations of average wind, saltation, and cross events were 1.87, 2.10, and 1.73 seconds, respectively. Integral time scales, calculated using normalized auto correlation and power spectral density analysis, were approximately two seconds for the wind and saltation systems. The temporal coincidence of the integral time scale estimations and the event durations for the wind and saltation system strongly suggests that wind events are driving sand transport events.

Ellis, Jean Taylor

2006-12-01T23:59:59.000Z

212

RIAPMTQ/Impact : beam-dynamics simulation tool for RIA.  

Science Conference Proceedings (OSTI)

We have developed a pair of multiparticle beam dynamics codes for end-to-end computer simulations of the proposed RIA heavy-ion driver linac. The two codes are: (1) an adaptation of PARMTEQ called RIAPMTQ for the normal-conducting-linac front end, and (2) IMPACT for the superconducting linac. The codes run on a PC as well as on parallel supercomputing platforms such as NERSC at LBNL. The parallel capability allows us to run simulations with large numbers of macroparticles for the computation of beam halo and beam-losses. The codes are being benchmarked for rms beam properties against previously existing codes at ANL and MSU. The work is being performed by a collaboration including LANL, LBNL, ANL, and Michigan State University (MSU). In this paper we present an overview, the status of the work, comparison of simulation results from RIAPMTQ and the ANL code TRACK for the ANL front-end design, and the first RIAPMTQ/IMPACT end-to-end multiprocessor simulation for the MSU design.

Wangler, T. P.; Billen, J. H.; Garnett, R. W.; Qiang, J.; Ryne, R.; Crandall, K. R.; Ostroumov, P.; Aseev, V. N.; Mustapha, B.; York, R. C.; Wu, X.; Zhao, Q.; Gorelov, D.; Doleans, M.; Physics; LANL; Tech Source; Michigan State Univ.

2006-01-01T23:59:59.000Z

213

Coherent Synchrotron Radiation: Theory and Simulations.  

Science Conference Proceedings (OSTI)

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

Novokhatski, Alexander; /SLAC

2012-03-29T23:59:59.000Z

214

Multidimensional study of a 50-MeV, 1500-rad/pulse radiographic linac, using the stagger-tuning concept  

Science Conference Proceedings (OSTI)

Stagger tuning of accelerator cavities, or blocks of cavities, can significantly enhance the achievable charge transfer through an electron linac operating in the stored-energy mode. The output bremsstrahlung flux can be increased over a conventional approach by an order of magnitude without any significant degradation in emittance growth or energy spread. Given a suitable injector, a 1500-rad/pulse, 50-MeV radiographic linac appears to be practical at a 400-MHz operating frequency; a 150-rad/pulse, 50-MeV radiographic linac will operate at 1300 MHz. A multidimensional study was made using the PARMELA code where several parameters, including beam current, synchronous phase angle, and beam radius, were varied while observing the effects on emittance and transmission efficiency.

Owen, R.K.; Fazio, M.V.; Boyd, T.J.

1983-01-01T23:59:59.000Z

215

Simulations of coherent beam-beam effects with head-on compensation  

SciTech Connect

Electron lenses are under construction for installation in RHIC in order to mitigate the head-on beam-beam effects. This would allow operation with higher bunch intensity and result in a significant increase in luminosity. We report on recent strong-strong simulations and experiments that were carried out using the RHIC upgrade parameters to assess the impact of coherent beam-beam effects in the presence of head-on compensation.

White S.; Fischer, W.; Luo. Y.

2012-05-20T23:59:59.000Z

216

A 4 to 0.1 nm FEL Based on the SLAC Linac  

Science Conference Proceedings (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

217

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

Science Conference Proceedings (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

218

Coherent optical control of electronic excitations in functionalized semiconductor nanostructures  

Science Conference Proceedings (OSTI)

The feasibility of creating and manipulating coherent quantum states on surfaces offunctionalized semiconductor nanostructures is computationally investigated. Quantumdynamics simulations of electron-hole transfer between catechol molecules adsorbed ... Keywords: adsorbates, coherent control, semiconductors, wave-packet dynamics

L. G. C. Rego; S. G. Abuabara; V. S. Batista

2005-07-01T23:59:59.000Z

219

Some Additional Coherence Data in the Inertial Subrange  

Science Conference Proceedings (OSTI)

Some coherence measurements, taken at the Näsudden wind energy test site, for small separation distances at a height of 65–77 m, are analyzed in terms of a theoretical coherence model for isotropic turbulence, and for Davenport similarity.

Ann-Sofi Smedman

1987-12-01T23:59:59.000Z

220

Quasi Light Fields: A Model of Coherent Image Formation  

E-Print Network (OSTI)

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

Accardi, Anthony J.

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

Direct Atmospheric Forcing of Geostrophic Eddies. Part II: Coherence Maps  

Science Conference Proceedings (OSTI)

The theory of stochastic atmospheric forcing of quasigeostrophic eddies is applied to calculate coherence maps, that is, the coherence between the oceanic response at one location and the atmospheric forcing at another location as a function of ...

Angelika Lippert; Peter Müller

1995-01-01T23:59:59.000Z

222

Coherence Maps for Wind-Forced Quasigeostrophic Flows  

Science Conference Proceedings (OSTI)

Coherence maps are a useful tool to study the oceanic response to atmospheric forcing. For a specific frequency band these maps display the coherence between the oceanic current (or pressure) at a single mooring location and the atmospheric ...

Peter Müller

1997-09-01T23:59:59.000Z

223

Agent communication pragmatics: the cognitive coherence approach  

Science Conference Proceedings (OSTI)

Different approaches have investigated the syntax and semantics of agent communication languages. However, these approaches have not indicated how agents should dynamically use communications. Instead of filling this pragmatics gap, most approaches have ... Keywords: Agent communication language, Cognitive coherence, Dialogue games, Multi-agents systems, Pragmatics, Social commitments

Philippe Pasquier; Brahim Chaib-Draa

2005-12-01T23:59:59.000Z

224

Delta Coherence Protocols: The Home Update Protocol  

SciTech Connect

We describe a new class of directory coherence protocols called delta coherence protocols that use network guarantees to support a new and highly concurrent approach to maintain a consistent shared memory. Delta coherence protocols are more concurrent than other coherence protocols in that they allow processes to pipeline memory accesses without violating sequential consistency; support multiple concurrent readers and writers to the same cache block; and allow processes to access multiple shared variables atomically without invalidating the copies held by other processes or otherwise obtaining exclusive access to the referenced variables. Delta protocols include both update and invalidate protocols. In this paper we describe the simplest, most basic delta protocol, an update protocol called the home update protocol. Delta protocols are based on isotach network guarantees. An isotach network maintains a logical time system that allows each process to predict and control the logical time at which its messages are received. Processes use isotach guarantees to control the logical time at which their requests on shared memory appear to be executed. We prove the home update protocol is correct using logical time to reason about the order in which requests are executed.

Williams, C.; Reynolds, P.F.; de Supinoki, B.

2000-07-21T23:59:59.000Z

225

Coherent multilayer crystals and method of making  

SciTech Connect

A new material consisting of a multilayer crystalline structure which is coherent perpendicular to the layers and where each layer is composed of a single crystalline element. The individual layers may vary from 2.ANG. to 100.ANG. or more in thickness.

Schuller, Ivan K. (Woodridge, IL); Falco, Charles M. (Tucson, AZ)

1984-01-01T23:59:59.000Z

226

Method of making coherent multilayer crystals  

DOE Patents (OSTI)

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

Schuller, Ivan K. (Woodridge, IL); Falco, Charles M. (Woodridge, IL)

1984-01-01T23:59:59.000Z

227

Deriving Efficient Cache Coherence Protocols Through Refinement  

Science Conference Proceedings (OSTI)

We address the problem of developing efficient cache coherence protocols for use in distributed systems implementing distributed shared memory (DSM) using message passing. A serious drawback of traditional approaches to this problem is that the users ... Keywords: DSM protocols, communication protocols, refinement

Ratan Nalumasu; Ganesh Gopalakrishnan

2002-01-01T23:59:59.000Z

228

Coherent Radiation Effects in the LCLS Undulator  

Science Conference Proceedings (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

229

Coherent multilayer crystals and method of making  

DOE Patents (OSTI)

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

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

1980-10-30T23:59:59.000Z

230

Brief paper: Structural archetypes for coherency  

Science Conference Proceedings (OSTI)

The power system model is divided into a study system (SS) and an external group (EG). Three structural archetypes for coherency (SAC) are defined. Each SAC is a set of structural conditions on the power system which when satisfied cause the EG to remain ... Keywords: Power systems, dynamic equivalents, modal analysis, singular perturbation

John F. Dorsey; Robert A. Schlueter

1984-05-01T23:59:59.000Z

231

Self-Amplified Spontaneous Emission in the Short Wavelength Coherent Radiation  

E-Print Network (OSTI)

Generation Light Sources, SSRL Report 92/02, page 315, M.linac being proposed by SLAC/SSRL/UCLA/LBL collaboration [

Kim, K.-J.

2011-01-01T23:59:59.000Z

232

Isolating quantum coherence with pathway-selective coherent multi-dimensional spectroscopy  

E-Print Network (OSTI)

Coherent coupling between spatially separated systems has long been explored as a necessary requirement for quantum information and cryptography. Recent discoveries suggest such phenomena appear in a much wider range of processes, including light-harvesting in photosynthesis. These discoveries have been facilitated by developments in coherent multi-dimensional spectroscopy (CMDS) that allow interactions between different electronic states to be identified in crowded spectra. For complex systems, however, spectral broadening and multiple overlapping peaks limit the ability to separate, identify and properly analyse all contributions. Here we demonstrate how pathway-selective CMDS can overcome these limitations to reveal, isolate and allow detailed analysis of weak coherent coupling between spatially separated excitons localised to different semiconductor quantum wells. Selective excitation of the coherence pathways, by spectrally shaping the laser pulses, provides access to previously hidden details and enable...

Tollerud, Jonathan O; Davis, Jeffrey A

2013-01-01T23:59:59.000Z

233

The hot prototype of the Pi-mode structure for LINAC4  

E-Print Network (OSTI)

The PIMS (Pi-Mode-Structure) cavities for Linac4 are made of 7 coupled cells operating in !-mode at a frequency of 352 MHz. The mechanical concept is derived from the 5-cell cavities used in the LEP machine, whereas cell length and coupling are adapted for proton acceleration in the range from 50 to 160 MeV. Linac4 will be the first machine to employ this type of cavities for low-beta protons. During the first years of operation the PIMS will be used at low duty cycle (0.1%) as part of the consolidated LHC proton injector complex. It is designed, however, to operate eventually in a high duty cycle (10%) proton injector, which could be used as proton front-end for neutrino or RIB applications. To prepare for the series construction of the 12 PIMS units the first cavity (102 MeV beam energy) has been designed and constructed at CERN, to be used as a hot prototype for RF tests and as a pre-series mechanical unit. In this paper we report on some of the design features, the construction experience, and first measu...

Gerigk, F; Bourquin, P; Dallocchio, A; Favre, G; Geisser, J M; Gentini, L; Giguet, J M; Mathot, S; Polini, M; Pugnat, D; Riffaud, B; Sgobba, S; Tardy, T; Ugena Tirado, P; Vretenar, M

2010-01-01T23:59:59.000Z

234

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

SciTech Connect

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

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

2012-05-15T23:59:59.000Z

235

SU(N) Coherent States and Irreducible Schwinger Bosons  

E-Print Network (OSTI)

We exploit the SU(N) irreducible Schwinger boson to construct SU(N) coherent states. This construction of SU(N) coherent state is analogous to the construction of the simplest Heisenberg-Weyl coherent states. The coherent states belonging to irreducible representations of SU(N) are labeled by the eigenvalues of the $(N-1)$ SU(N) Casimir operators and are characterized by $(N-1)$ complex orthonormal vectors describing the SU(N) group manifold.

Manu Mathur; Indrakshi Raychowdhury

2010-07-09T23:59:59.000Z

236

WAYPOINT: scaling coherence to thousand-core architectures  

Science Conference Proceedings (OSTI)

In this paper, we evaluate a set of coherence architectures in the context of a 1024-core chip multiprocessor (CMP) tailored to throughput-oriented parallel workloads. Based on our analysis, we develop and evaluate two techniques for scaling coherence ... Keywords: accelerator architecture, cache coherence, probe filtering

John H. Kelm; Matthew R. Johnson; Steven S. Lumettta; Sanjay J. Patel

2010-09-01T23:59:59.000Z

237

Particle Production of Coherently Oscillating Nonclassical Inflaton in FRW Universe  

E-Print Network (OSTI)

We study particle production of coherently oscillating inflaton in the semiclassical theory of gravity by representing inflaton in coherent and squeezed state formalisms. A comparative study of the inflaton in classical gravity with coherent state inflaton in semiclassical gravity is also presented.

K. K. Venkataratnam; P. K. Suresh

2004-02-18T23:59:59.000Z

238

Statistical evaluation of coherence estimated from optimally beamformed signals  

Science Conference Proceedings (OSTI)

In this paper we investigate a situation where we want to perform a coherence analysis of two signal sources, one of which is measured directly, and the other is measured through a sensor array affected by noise. To extract the latter signal, we suggest ... Keywords: Beamforming, Cortico-muscular coherence, Magnitude squared coherence, Statistical distribution

Radoslav Bortel, Pavel Sovka

2013-09-01T23:59:59.000Z

239

Coherent State Distinguishability in Continuous Variable Quantum Cryptography  

E-Print Network (OSTI)

We use the probability of error as a measure of distinguishability between two pure and two mixed symmetric coherent states in the context of continuous variable quantum cryptography. We show that the two mixed symmetric coherent states (in which the various components have the same real part) never give an eavesdropper more information than two pure coherent states.

Christian Weedbrook; Mile Gu; Andrew M. Lance; Thomas Symul; Ping Koy Lam; Timothy C. Ralph

2007-03-15T23:59:59.000Z

240

Using Quantum Coherence to Enhance Gain in Atomic Physics  

E-Print Network (OSTI)

Quantum coherence and interference effects in atomic and molecular physics has been extensively studied due to intriguing counterintuitive physics and potential important applications. Here we present one such application of using quantum coherence to generate and enhance gain in extreme ultra-violet(XUV)(@58.4nm in Helium) and infra-red(@794.76nm in Rubidium) regime of electromagnetic radiation. We show that using moderate external coherent drive, a substantial enhancement in the energy of the lasing pulse can be achieved under optimal conditions. We also discuss the role of coherence. The present paper is intended to be pedagogical on this subject of coherence-enhanced lasing.

Pankaj K. Jha

2013-01-28T23:59:59.000Z

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

Linac 2006  

NLE Websites -- All DOE Office Websites (Extended Search)

Photo Ripley's Aquarium Photo Cades Cove Photo Museum of Appalachia Dollywood Steam Train Spallation Neutron Source The conference is over The conference proceedings are...

242

Studies of eRHIC coherent instabilities  

Science Conference Proceedings (OSTI)

In the presence of an effective coherent electron cooling, the rms ion bunch length in eRHIC will be kept at 8.3 cm for 250 GeV protons, which is much shorter than the current RHIC 45 cm rms bunch length. Together with the increased bunch intensity and total bunch number, coherent instabilities could be a potential limitation for achieving desired machine performance. In this study, we use the tracking code TRANFT to find thresholds and growth rates for single bunch and coupled bunch instabilities with linear chromaticity and amplitude dependent tune shift taken into account. Based on the simulation results, requirements of machine parameters such as rf voltage, linear chromaticity, and tune dependence of betatron amplitude are specified to suppress these instabilities.

Wang G.; Blaskiewicz, M.

2012-05-20T23:59:59.000Z

243

Coherent spin control by electromagnetic vacuum fluctuations  

SciTech Connect

In coherent control, electromagnetic vacuum fluctuations usually cause coherence loss through irreversible spontaneous emission. However, since the dissipation via emission is essentially due to correlation of the fluctuations, when emission ends in a superposition of multiple final states, correlation between different pathways may build up if the 'which way' information is not fully resolved (i.e., the emission spectrum is broader than the transition energy range). Such correlation can be exploited for spin-flip control in a {Lambda}-type three-level system, which manifests itself as an all-optical spin echo in nonlinear optics with two orders of optical fields saved as compared with stimulated Raman processes. This finding represents a class of optical nonlinearity induced by electromagnetic vacuum fluctuations.

Wang Jing [Department of Physics, Chinese University of Hong Kong, Shatin, N.T. (Hong Kong); Department of Physics, Tsinghua University, Beijing 100084 (China); Liu Renbao [Department of Physics, Chinese University of Hong Kong, Shatin, N.T. (Hong Kong); Zhu Bangfen [Department of Physics, Tsinghua University, Beijing 100084 (China); Institute of Advanced Study, Tsinghua University, Beijing 100084 (China); Sham, L. J. [Department of Physics, University of California-San Diego, La Jolla, California 92093-0319 (United States); Steel, D. G. [H. M. Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2011-05-15T23:59:59.000Z

244

Method and apparatus for coherent burst ranging  

DOE Patents (OSTI)

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

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

1998-04-28T23:59:59.000Z

245

Method and apparatus for coherent burst ranging  

DOE Patents (OSTI)

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

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

1998-01-01T23:59:59.000Z

246

COHERENT LASER VISION SYSTEM (CLVS) OPTION PHASE  

Science Conference Proceedings (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

247

Coherence delay augmented laser beam homogenizer  

DOE Patents (OSTI)

It is an object of the present invention to provide an apparatus that can reduce the apparent coherence length of a laser beam so the beam can be used with an inexpensive homogenizer to produce an output beam with a uniform spatial intensity across its entire cross section. It is a further object of the invention to provide an improved homogenizer with a variable aperture size that is simple and easily made. It is still an additional object of the invention to provide an improved liquid filled homogenizer utilizing total internal reflection for improved efficiency. These, and other objects of the invention are realized by using a ``coherence delay line,`` according to the present invention, in series between a laser and a homogenizer. The coherence delay line is an optical ``line`` that comprises two mirrors, one partially reflecting, and one totally reflecting, arranged so that light incident from the laser first strikes the partially reflecting mirror. A portion of the beam passes through, and a portion is reflected back to the totally reflecting mirror.

Rasmussen, P.; Bernhardt, A.

1991-12-31T23:59:59.000Z

248

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

SciTech Connect

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

WANG,X.J.

2001-01-22T23:59:59.000Z

249

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

SciTech Connect

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

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

2011-03-28T23:59:59.000Z

250

A Quest for Measuring Ion Bunch Longitudinal Profiles with One Picosecond Accuracy in the SNS Linac.  

Science Conference Proceedings (OSTI)

The SNS linac utilizes several accelerating structures operating at different frequencies and with different transverse focusing structures. Low-loss beam transport requires a careful matching at the transition points in both the transverse and longitudinal axes. Longitudinal beam parameters are measured using four Bunch Shape Monitors (used at many ion accelerator facilities, aka Feschenko devices). These devices, as initially delivered to the SNS, provided an estimated accuracy of about 5 picoseconds, which was sufficient for the initial beam commissioning. New challenges of improving beam transport for higher power operation will require measuring bunch profiles with 1-2 picoseconds accuracy. We have successfully implemented a number of improvements to maximize the performance characteristics of the delivered devices. We will discuss the current status of this instrument, its ultimate theoretical limit of accuracy, and how we measure its accuracy and resolution with real beam conditions.

Aleksandrov, Alexander V [ORNL; Dickson, Richard W [ORNL

2012-01-01T23:59:59.000Z

251

AUTOMATED OPERATION OF THE APS LINAC USING THE PROCEDURE EXECUTION MANAGER  

E-Print Network (OSTI)

The Advanced Photon Source (APS) linear accelerator has two thermionic cathode rf guns and one photocathode rf gun. The thermionic guns are used primarily for APS operations while the photocathode gun is used as a freeelectron laser (FEL) driver. With each gun requiring a different lattice and timing configuration, the need to change quickly between guns puts great demands on the accelerator operators. Using the Procedure Execution Manager (PEM), a software environment for managing automated procedures, we have made start-up and switchover of the linac systems both easier and more reliable. The PEM is a graphical user interface written in Tcl/Tk that permits the user to invoke ‘machine procedures ’ and control their execution. It allows

unknown authors

2000-01-01T23:59:59.000Z

252

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

Science Conference Proceedings (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

253

Measurement of ion beam profiles in a superconducting linac with a laser wire  

Science Conference Proceedings (OSTI)

A laser wire ion beam profile monitor system has been developed at the Spallation Neutron Source accelerator complex. The laser wire system uses a single laser source to measure the horizontal and vertical profiles of a pulsed hydrogen ion (H{sup -}) beam along a 230 m long superconducting linac, which accelerates H{sup -} from 200 MeV to 1 GeV. In this paper, we describe the laser optics requirement for the system, the performance of the profile measurement, and the effects of laser parameters on the measurement reliability. The result provides a practical guideline for the development of a large-scale, operational, laser-based diagnostics in accelerator facilities.

Liu Yun; Long, Cary; Peters, Charles; Aleksandrov, Alexander

2010-12-10T23:59:59.000Z

254

Parametic Study of the current limit within a single driver-scale transport beam line of an induction Linac for Heavy Ion Fusion  

E-Print Network (OSTI)

of the RIA or SNS beam lines. ..the Spallation Neutron Source (SNS) Front End [38,39,40] anddistributions. For example the SNS linac [38,166] or Rare

Prost, Lionel Robert

2007-01-01T23:59:59.000Z

255

OECD-International Platform on Policy Coherence for Development | Open  

Open Energy Info (EERE)

International Platform on Policy Coherence for Development International Platform on Policy Coherence for Development Jump to: navigation, search Tool Summary Name: OECD-International Platform on Policy Coherence for Development Agency/Company /Organization: Organisation for Economic Co-Operation and Development (OECD) Focus Area: Economic Development Topics: Co-benefits assessment Resource Type: Guide/manual, Lessons learned/best practices, Technical report User Interface: Website Website: community.oecd.org/community/pcd Cost: Free Language: English OECD-International Platform on Policy Coherence for Development Screenshot References: OECD-International Platform on Policy Coherence for Development[1] "The "International Platform on Policy Coherence for Development"" is intended as an interactive tool to be built up over time. It contains four

256

Environmental Impact  

U.S. Energy Information Administration (EIA)

Environmental Impact - a single comprehensive bibliographic information resource on climate change & other impacts of humans on the biosphere.

257

Experimental demonstration of a Hadamard gate for coherent state qubits  

SciTech Connect

We discuss and make an experimental test of a probabilistic Hadamard gate for coherent state qubits. The scheme is based on linear optical components, nonclassical resources, and the joint projective action of a photon counter and a homodyne detector. We experimentally characterize the gate for the coherent states of the computational basis by full tomographic reconstruction of the transformed output states. Based on the parameters of the experiment, we simulate the fidelity for all coherent state qubits on the Bloch sphere.

Tipsmark, Anders; Laghaout, Amine; Andersen, Ulrik L. [Department of Physics, Technical University of Denmark, Fysikvej, DK-2800 Kgs. Lyngby (Denmark); Dong, Ruifang [Quantum Frequency Standards Division, National Time Service Center (NTSC), Chinese Academy of Sciences, 710600 Lintong, Shaanxi (China); Department of Physics, Technical University of Denmark, Fysikvej, DK-2800 Kgs. Lyngby (Denmark); Marek, Petr [Department of Optics, Palacky University, 17. listopadu 12, CZ-77146 Olomouc (Czech Republic); Jezek, Miroslav [Department of Optics, Palacky University, 17. listopadu 12, CZ-77146 Olomouc (Czech Republic); Department of Physics, Technical University of Denmark, Fysikvej, DK-2800 Kgs. Lyngby (Denmark)

2011-11-15T23:59:59.000Z

258

Photon-added Coherent States in Parametric Down-conversion  

E-Print Network (OSTI)

Photon-added coherent states have been realized in optical parametric down-conversion by Zavatta {\\em et al} [Science 306 (2004) 660-662]. In this report, it is established that the states generated in the process are {\\em ideal} photon-added coherent states. It is shown that the scheme can generate higher order photon-added coherent states. A comparative study of the down-conversion process and atom-cavity interaction in generating the photon-added coherent states is presented.

S. Sivakumar

2011-01-20T23:59:59.000Z

259

Coherent Anti-Stokes Raman Spectroscopy (CARS) - Available ...  

Search PNNL. PNNL Home; About; Research; Publications; Jobs; News; Contacts; Coherent Anti-Stokes Raman Spectroscopy (CARS) Battelle Number(s): 11982. ...

260

Photon-added coherent states for exactly solvable Hamiltonians  

E-Print Network (OSTI)

Photon-added Gazeau-Klauder and Klauder-Perelomov coherent states are investigated. Application to P\\"oschl-Teller potentials is given.

M. Daoud

2004-09-18T23:59:59.000Z

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.


261

Resonator for Coherent Addition of Semiconductor Laser Arrays ...  

Resonator for Coherent Addition of Semiconductor Laser Arrays and Applications for a Solar Pumped Laser Array Oak Ridge National Laboratory. Contact ...

262

Optimization of Real Asset Portfolio using a Coherent Risk Measure  

E-Print Network (OSTI)

Nov 19, 2008 ... Optimization of Real Asset Portfolio using a Coherent Risk Measure: ... initial techniques evolved to the use of enterprise portfolio management, ...

263

A Broader Perspective about Organization and Coherence in Biological Systems  

E-Print Network (OSTI)

The implications of large-scale coherence in biological systems and possible links to quantum theory are only beginning to be explored. Whether quantum-like coherent phenomena are relevant, or even possible at all, at the high temperatures of biological systems remains unsettled. Here, we present a broader perspective on biological organization and how quantum-like dynamics and coherence might shape the very fabric from which complex biological systems are organized. Regardless of its exact nature, a unique form of coherence seems apparent at multiple scales in biology and its better characterization may have broad consequences for the understanding of living organisms as complex systems.

Martin Robert

2012-12-03T23:59:59.000Z

264

Minimally invasive diagnostic imaging using high resolution Optical Coherence Tomography  

E-Print Network (OSTI)

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

Herz, Paul Richard, 1972-

2004-01-01T23:59:59.000Z

265

Security improvement of using modified coherent state for quantum cryptography  

E-Print Network (OSTI)

Weak coherent states as a photon source for quantum cryptography have limit in secure data rate and transmission distance because of the presence of multi-photon events and loss in transmission line. Two-photon events in a coherent state can be taken out by a two-photon interference scheme. We investigate the security issue of utilizing this modified coherent state in quantum cryptography. A 4 dB improvement in secure data rate or a nearly two-fold increase in transmission distance over the coherent state are found. With a recently proposed and improved encoding strategy, further improvement is possible.

Y. J. Lu; Luobei Zhu; Z. Y. Ou

2005-01-30T23:59:59.000Z

266

Efficient quantum computing using coherent photon conversion  

E-Print Network (OSTI)

Single photons provide excellent quantum information carriers, but current schemes for preparing, processing and measuring them are inefficient. For example, down-conversion provides heralded, but randomly timed single photons, while linear-optics gates are inherently probabilistic. Here, we introduce a deterministic scheme for photonic quantum information. Our single, versatile process---coherent photon conversion---provides a full suite of photonic quantum processing tools, from creating high-quality heralded single- and multiphoton states free of higher-order imperfections to implementing deterministic multiqubit entanglement gates and high-efficiency detection. It fulfils all requirements for a scalable photonic quantum computing architecture. Using photonic crystal fibres, we experimentally demonstrate a four-colour nonlinear process usable for coherent photon conversion and show that current technology provides a feasible path towards deterministic operation. Our scheme, based on interacting bosonic fields, is not restricted to optical systems, but could also be implemented in optomechanical, electromechanical and superconducting systems which exhibit extremely strong intrinsic nonlinearities.

N. K. Langford; S. Ramelow; R. Prevedel; W. J. Munro; G. J. Milburn; A. Zeilinger

2011-06-10T23:59:59.000Z

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

Cache coherence tradeoffs in shared-memory MPSoCs  

Science Conference Proceedings (OSTI)

Shared memory is a common interprocessor communication paradigm for single-chip multiprocessor platforms. Snoop-based cache coherence is a very successful technique that provides a clean shared-memory programming abstraction in general-purpose chip multiprocessors, ... Keywords: Cache coherence, low power, multiprocessor, system-on-chip

Mirko Loghi; Massimo Poncino; Luca Benini

2006-05-01T23:59:59.000Z

270

Fast approximation of matrix coherence and statistical leverage  

Science Conference Proceedings (OSTI)

The statistical leverage scores of a matrix A are the squared row-norms of the matrix containing its (top) left singular vectors and the coherence is the largest leverage score. These quantities are of interest in recently-popular problems such as matrix ... Keywords: matrix coherence, randomized algorithm, statistical leverage

Petros Drineas; Malik Magdon-Ismail; Michael W. Mahoney; David P. Woodruff

2012-01-01T23:59:59.000Z

271

Design Construction and Test Results of a HTS Solenoid For Energy Recovery Linac  

SciTech Connect

An innovative feature of the proposed Energy Recovery Linac (ERL) is the use of a solenoid made with High Temperature Superconductor (HTS) with the Superconducting RF cavity. The use of HTS allows solenoid to be placed in close proximity to the cavity and thus provides early focusing of the electron beam. In addition, cryogenic testing at {approx}77 K is simpler and cheaper than 4 K testing. This paper will present the design, construction and test results of this HTS solenoid. The HTS solenoid in the proposed ERL will be situated in the transition region between the superconducting cavity at {approx}4 K and the cryostat at the room temperature. Solenoid inside the cryogenic structure provides an early focusing and hence low emittance beam. The temperature in the transition region will be too high for a conventional low temperature superconductor and resistive heat load from copper coils will be too high on cryogenic system. HTS coils also allow much higher current density and significant reduction in size as compared to copper coils. Hence HTS solenoid provide a unique and technically superior solution. The use of a HTS solenoid with superconducting cavity offers a unique option as it can be placed in a cold to warm transition region to provide early focussing without using additional space. Construction and test results so far are very encouraging for its use in the ERL project.

Anerella, M; Ben-Zvi, I; Kayran, D; McIntyre, G; Muratore, J; Plate, S; Sampson, W; Cole, M

2011-03-28T23:59:59.000Z

272

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

SciTech Connect

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

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

2011-03-28T23:59:59.000Z

273

Tematea: Issue Based Modules for Coherent Implementation of Biodiversity  

Open Energy Info (EERE)

Tematea: Issue Based Modules for Coherent Implementation of Biodiversity Tematea: Issue Based Modules for Coherent Implementation of Biodiversity Conventions Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Tematea: Issue Based Modules for Coherent Implementation of Biodiversity Conventions Agency/Company /Organization: United Nations Environment Programme, International Union for Conservation of Nature Sector: Land Topics: Implementation, Co-benefits assessment, - Environmental and Biodiversity Resource Type: Guide/manual, Training materials, Lessons learned/best practices Website: www.tematea.org Tematea: Issue Based Modules for Coherent Implementation of Biodiversity Conventions Screenshot References: Tematea[1] Summary "The TEMATEA Project on Issue-Based Modules supports a better and more coherent national implementation of biodiversity-related conventions

274

Polaron Coherence Condensation in Layered Colossal Resistive Manganites  

NLE Websites -- All DOE Office Websites (Extended Search)

Polaron Coherence Condensation Polaron Coherence Condensation in Layered Colossal Resistive Manganites Polaron Coherence Condensation in Layered Colossal Resistive Manganites Print Wednesday, 30 July 2008 00:00 Novel quantum phenomena, such as high-temperature superconductivity (HTSC) and colossal magnetoresistance (CMR), arise in certain materials where the interactions between electrons are very strong, but the mechanism driving their appearance remains a major puzzle. Now, angle-resolved photoemission findings from an international team led by researchers from Stanford University and the ALS provide the first direct spectroscopic evidence that the transition from insulator to metal in CMR manganese oxides (manganites) results from coherent "polaron condensation." The new findings also suggest that coherence-driven transitions are a generic controlling factor for novel quantum phenomena in doped transition-metal oxides.

275

Dynamic Coherence in Excitonic Molecular Complexes under Various Excitation Conditions  

E-Print Network (OSTI)

In this paper, we investigate the relevance of dynamic electronic coherence under conditions natural to light-harvesting systems. We formulate the results of a quantum mechanical treatment of a weak light-matter interaction in terms of experimental observable, such as the incident light spectrum and the absorption spectrum of the material, and we derive the description of the incoherent F\\"orster type energy transfer fully from the wave function formalism. We demonstrate that excitation of a coherent superposition of electronic eigenstates of natural light-harvesting complexes by sunlight or by excitation transfer from a neighboring antenna is unlikely and that dynamical coherence therefore cannot play any significant role in natural photosynthesis, regardless of their life time. Dynamical coherence as a transient phenomenon must be strictly distinguished from the effect of excited state delocalization (also termed quantum coherence in the literature) which is established by interaction between the pigments a...

Chenu, Aurélia; Mancal, Tomáš

2013-01-01T23:59:59.000Z

276

VORPAL Simulations Relevant to Coherent Electron Cooling  

SciTech Connect

Coherent electron cooling (CEC)* combines the best features of electron cooling and stochastic cooling, via free-electron laser technology**, to offer the possibility of cooling high-energy hadron beams with order-of-magnitude shorter cooling times. Many technical difficulties must be resolved via full-scale 3D simulations, before the CEC concept can be validated experimentally. VORPAL is the ideal code for simulating the â modulatorâ and â kickerâ regions, where the electron and hadron beams will co-propagate as in a conventional electron cooling section. Unlike previous VORPAL simulations*** of electron cooling physics, where dynamical friction on the ions was the key metric, it is the details of the electron density wake driven by each ion in the modulator section that must be understood, followed by strong amplification in the FEL. We present some initial simulation results. In particular, we compare the semi-analytic binary collision model with electrostatic particle-in-cell (PIC).

Bell, G.I.; Bruhwiler, D.L.; Sobol, A.V.; Ben-Zvi, Ilan; Litvinenko, Vladimir; Derbenev, Yaroslav

2008-07-01T23:59:59.000Z

277

VORPAL simulations relevant to coherent electron cooling  

Science Conference Proceedings (OSTI)

Coherent electron cooling (CEC) [1] combines the best features of electron cooling and stochastic cooling, via free-electron laser technology [2], to offer the possibility of cooling high-energy hadron beams with order-of-magnitude shorter cooling times. Many technical difficulties must be resolved via full-scale 3D simulations, before the CEC concept can be validated experimentally. VORPAL is the ideal code for simulating the modulator and kicker regions, where the electron and hadron beams will co-propagate as in a conventional electron cooling section. Unlike previous VORPAL simulations [3] of electron cooling physics, where dynamical friction on the ions was the key metric, it is the details of the electron density wake driven by each ion in the modulator section that must be understood, followed by strong amplification in the FEL. We present some initial simulation results.

Bell,G.; Bruhwiler, D.; Sobol, A.; Ben-Zvi, I.; Litvinenko, V.; Derbenev, Y.

2008-06-23T23:59:59.000Z

278

Birefringence insensitive optical coherence domain reflectometry system  

DOE Patents (OSTI)

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

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

2002-01-01T23:59:59.000Z

279

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

280

TESLA Report 2003-10 Studies of Electromagnetic Cascade Showers Development in the TESLA Main Linac Initiated by Electron Field Emission in RF Cavities  

E-Print Network (OSTI)

this paper, and, in order to see this point more clearly, none of the other possible particle multiplication processes will be included in our simulations. 2 Simulation Procedure and Code Design The process of particle transport in our computer code DUST (DUnkel STrom, in German) is organized in such a way that it naturally breaks down into two parts, Monte Carlo simulation of the electromagnetic shower development when a particle impacts the inner vacuum surface of the accelerator, and particle dynamics in an electromagnetic field inside the accelerator vacuum. As usual, the accelerator to be studied is described as a sequence of physical elements. The user specifies the element geometry, materials and electromagnetic fields. And although we have not implemented something similar to the MAD [20] lattice description language yet, to simplify the accelerator description, elements in our program can be grouped into di#erent modules, from modules one constructs cells, and a sequence of cells forms the linac. 2.1 Particle Transport in Nonvacuum Media When an energetic primary particle incidents on a mass of material of su#cient thickness a cascade of particles and electromagnetic radiation of great complexity results, and the most practical way to obtain the characteristics of this cascade, the distribution and parameters of secondary particles, especially for complicated material geometries, is through Monte Carlo simulations. Even though a code for the transport of high energy particles (in GeV range) can be developed without too great complications (see, for example, [21], [22]), the accurate simulation of the low energy particles is a very demanding e#ort. So, it is obvious, that it is better to use a thoroughly tested, standard programme, based on an extensive and r...

Balandin Brinkmann Flottmann; V. Bal; R. Brinkmann; K. Flöttmann; N. Golubeva

2003-01-01T23:59:59.000Z

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.


281

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

2013-01-17T23:59:59.000Z

282

Some features of photolithography image formation in partially coherent light  

SciTech Connect

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

Kitsak, M A [Cooperative Association for Internet Data Analysis, University of California, San Diego (United States); Kitsak, A I [Department of Laser Physics and Spectroscopy, Belarusian State University, Minsk (Belarus)

2010-12-09T23:59:59.000Z

283

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

SciTech Connect

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

284

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 INTRODUCTION The Rensselaer Polytechnic Institute (RPI) nuclear data program utilizes a 60 MeV pulsed electron Linear Accelerator (LINAC) to produce short pulses of neutrons for nuclear data measurements1 . Neutron

Danon, Yaron

285

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

286

Spectra of photons and neutrons generated in a heterogeneous head of a 15 MV LINAC at differents field sizes  

SciTech Connect

Spectra of photons and neutrons were calculated, using the Monte Carlo code MCNP-5 using the e/p/n mode. A heterogeneous model was used to define the linac head where the collimators were modeled to produce five different treatment fields at the isocenter. Photon and neutron spectra were estimated in several points along two directions from the isocenter. The total photon fluence beyond 60 cm behaves according to 1/r{sup 2} rule, while total neutron fluence, beyond 80 cm, can be described by diffusion theory using an infinite plane as a neutron source.

Benites-Rengifo, J. L.; Vega-Carrillo, H. R.; Velazquez-Fernandez, J. B. [Posgrado en CBAP, Universidad Autonoma de Nayarit, Carretera Tepic-Compostela km 9. C.P. 63780. Xalisco, Nayarit (Mexico); Unidad Academica de Estudios Nucleares, Universidad Autonoma de Zacatecas, Apdo. Postal 336, 98000 Zacatecas, Zac. (Mexico); Posgrado en CBAP, Universidad Autonoma de Nayarit, Carretera Tepic-Compostela km 9. C.P. 63780. Xalisco, Nayarit (Mexico)

2012-10-23T23:59:59.000Z

287

Generation of coherent structures after cosmic inflation  

Science Conference Proceedings (OSTI)

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

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

2011-05-01T23:59:59.000Z

288

Polaron Coherence Condensation in Layered Colossal Resistive Manganites  

NLE Websites -- All DOE Office Websites (Extended Search)

Polaron Coherence Condensation in Layered Colossal Resistive Manganites Print Polaron Coherence Condensation in Layered Colossal Resistive Manganites Print Novel quantum phenomena, such as high-temperature superconductivity (HTSC) and colossal magnetoresistance (CMR), arise in certain materials where the interactions between electrons are very strong, but the mechanism driving their appearance remains a major puzzle. Now, angle-resolved photoemission findings from an international team led by researchers from Stanford University and the ALS provide the first direct spectroscopic evidence that the transition from insulator to metal in CMR manganese oxides (manganites) results from coherent "polaron condensation." The new findings also suggest that coherence-driven transitions are a generic controlling factor for novel quantum phenomena in doped transition-metal oxides.

289

Spatial Coherence of Tropical Rainfall at the Regional Scale  

Science Conference Proceedings (OSTI)

This study examines the spatial coherence characteristics of daily station observations of rainfall in five tropical regions during the principal rainfall season(s): the Brazilian Nordeste, Senegal, Kenya, northwestern India, and northern ...

Vincent Moron; Andrew W. Robertson; M. Neil Ward; Pierre Camberlin

2007-11-01T23:59:59.000Z

290

An 11-cm Coherent Polarimetric Radar for Meteorological Research  

Science Conference Proceedings (OSTI)

The Geophysics Directorate of the U.S. Air Force developed a unique 11-cm (S-band) coherent polarimetric radar. The radar can transmit signals of alternating orthogonal polarizations, with either circular or linear basis, and receive signals of ...

James I. Metcalf; Alexander W. Bishop; Richard C. Chanley; Timothy C. Hiett; Pio J. Petrocchi

1993-06-01T23:59:59.000Z

291

Argumentation and Persuasion in the Cognitive Coherence Theory  

Science Conference Proceedings (OSTI)

This paper presents a coherentist approach to argumentation that extends previous proposals on cognitive coherence based agent communication pragmatics (inspired from social psychology) and propose (1) an alternative view on argumentation that is (2) ...

Philippe Pasquier; Iyad Rahwan; Frank Dignum; Liz Sonenberg

2006-05-01T23:59:59.000Z

292

Effects of Wind Turbulence on Coherent Doppler Lidar Performance  

Science Conference Proceedings (OSTI)

The effects of wind turbulence on pulsed coherent Doppler lidar performance are investigated theoretically and with computer simulations. The performance of velocity estimators is determined for the case of a single realization of a wind field ...

Rod Frehlich

1997-02-01T23:59:59.000Z

293

Polaron Coherence Condensation in Layered Colossal Resistive Manganites  

NLE Websites -- All DOE Office Websites (Extended Search)

Polaron Coherence Condensation in Layered Colossal Resistive Manganites Print Polaron Coherence Condensation in Layered Colossal Resistive Manganites Print Novel quantum phenomena, such as high-temperature superconductivity (HTSC) and colossal magnetoresistance (CMR), arise in certain materials where the interactions between electrons are very strong, but the mechanism driving their appearance remains a major puzzle. Now, angle-resolved photoemission findings from an international team led by researchers from Stanford University and the ALS provide the first direct spectroscopic evidence that the transition from insulator to metal in CMR manganese oxides (manganites) results from coherent "polaron condensation." The new findings also suggest that coherence-driven transitions are a generic controlling factor for novel quantum phenomena in doped transition-metal oxides.

294

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

NLE Websites -- All DOE Office Websites (Extended Search)

10:00am SLAC, Bldg. 137, Room 226 Keoki Seu Seminar: With the advent of free electron lasers there has been interest in using coherent x-rays to probe condensed matter systems....

295

Modeling Pulse-to-Pulse Coherent Doppler Sonar  

Science Conference Proceedings (OSTI)

Coherent Doppler sonar provides a powerful tool for probing boundary layer flows under field and laboratory conditions. However, velocity profiling applications of this technique are complicated by characteristic velocity and range ambiguities. ...

L. Zedel

2008-10-01T23:59:59.000Z

296

Scalable directoryless shared memory coherence using execution migration  

E-Print Network (OSTI)

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

Lis, Mieszko

2010-11-22T23:59:59.000Z

297

The minimum-uncertainty coherent states for Landau levels  

Science Conference Proceedings (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

298

The mediating role of coherence in curriculum implementation  

Science Conference Proceedings (OSTI)

Implementation of inquiry-based curriculum materials has been a challenge in science education. Recent research points to the importance of coherence in professional development as a means to improving implementation. Policy researchers have defined ...

William Penuel; Barry J. Fishman; Lawrence P. Gallagher; Christine Korbak; Bladimir Lopez-Prado

2008-06-01T23:59:59.000Z

299

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

300

Coherent combination of slab-coupled optical waveguide lasers  

E-Print Network (OSTI)

A long-standing challenge for semiconductor lasers is scaling the optical power and brightness of many diode lasers by coherent beam combination. Because single-mode semiconductor lasers have limited power available from ...

Dorsch, Friedhelm

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

Spatial Coherence and Seasonal Predictability of Monsoon Onset over Indonesia  

Science Conference Proceedings (OSTI)

The seasonal potential predictability of monsoon onset during the August–December season over Indonesia is studied through analysis of the spatial coherence of daily station rainfall and gridded pentad precipitation data from 1979 to 2005. The ...

Vincent Moron; Andrew W. Robertson; Rizaldi Boer

2009-02-01T23:59:59.000Z

302

Spatial Coherence and Predictability of Indonesian Wet Season Rainfall  

Science Conference Proceedings (OSTI)

Rainfall from 63 stations across Indonesia is examined for the period 1950–98 to determine the spatial coherence of wet season anomalies. An example of almost unrelated anomalies at two neighboring stations is presented. Principal component ...

Malcolm Haylock; John McBride

2001-09-01T23:59:59.000Z

303

Asymptotic Properties of an Autocorrelation Coefficient for Coherent Doppler Sonar  

Science Conference Proceedings (OSTI)

A new formula is derived for the asymptotic form of the magnitude of an autocorrelation coefficient for coherent Doppler sonar. The autocorrelation magnitude is shown to be a biased estimator in the limit of infinite ensemble length. Numerical ...

Jeremy Dillon; Len Zedel; Alex E. Hay

2011-07-01T23:59:59.000Z

304

Generation of coherent terahertz pulses in ruby at room temperature  

Science Conference Proceedings (OSTI)

We have shown that a coherently driven solid state medium can potentially produce strong controllable short pulses of THz radiation. The high efficiency of the technique is based on excitation of maximal THz coherence by applying resonant optical pulses to the medium. The excited coherence in the medium is connected to macroscopic polarization coupled to THz radiation. We have performed detailed simulations by solving the coupled density matrix and Maxwell equations. By using a simple V-type energy scheme for ruby, we have demonstrated that the energy of generated THz pulses ranges from hundreds of pico-Joules to nano-Joules at room temperature and micro-Joules at liquid helium temperature, with pulse durations from picoseconds to tens of nanoseconds. We have also suggested a coherent ruby source that lases on two optical wavelengths and simultaneously generates THz radiation. We discussed also possibilities of extension of the technique to different solid-state materials.

Kuznetsova, Elena; Rostovtsev, Yuri; Kalugin, Nikolai G.; Kolesov, Roman; Kocharovskaya, Olga [Institute for Quantum Studies and Department of Physics, Texas A and M University, College Station, Texas 77843 (United States); Scully, Marlan O. [Institute for Quantum Studies and Department of Physics, Texas A and M University, College Station, Texas 77843 (United States); Princeton Institute for Material Science and Department of Mechanical and Aerospace Engineering, Princeton University, New Jersey 08544 (United States)

2006-08-15T23:59:59.000Z

305

Estimating Spatial Velocity Statistics with Coherent Doppler Lidar  

Science Conference Proceedings (OSTI)

The spatial statistics of a simulated turbulent velocity field are estimated using radial velocity estimates from simulated coherent Doppler lidar data. The structure functions from the radial velocity estimates are processed to estimate the ...

Rod Frehlich; Larry Cornman

2002-03-01T23:59:59.000Z

306

Observation of Coherence in the Photosystem II Reaction Center  

E-Print Network (OSTI)

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

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

2013-10-03T23:59:59.000Z

307

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

308

Quasi light fields: Extending the light field to coherent radiation  

E-Print Network (OSTI)

Imaging technologies such as dynamic viewpoint generation are engineered for incoherent radiation using the traditional light field, and for coherent radiation using electromagnetic field theory. We present a model of ...

Accardi, Anthony J.

309

Accumulation of different visual feature descriptors in a coherent framework  

Science Conference Proceedings (OSTI)

We present a temporal accumulation scheme which disambiguates different kinds of visual 3D descriptors within one coherent framework. The accumulation consists of a twofold process: First, by means of a Bayesian filtering outliers become eliminated and ...

Jeppe Barsøe Jessen; Florian Pilz; Dirk Kraft; Nicolas Pugeault; Norbert Krüger

2011-05-01T23:59:59.000Z

310

Spatial Coherence of Monthly Precipitation in the United States  

Science Conference Proceedings (OSTI)

Factor analysis and an orthogonal rotation to the varimax criterion are used to identify the synoptic-scale regions of the United States over which monthly precipitation amounts show the greatest spatial coherence. The regions are consistent with ...

John E. Walsh; Michael B. Richman; David W. Allen

1982-04-01T23:59:59.000Z

311

Coherent multi-photon interference and compensation of polarization dispersion  

E-Print Network (OSTI)

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

Fini, John Michael

2001-01-01T23:59:59.000Z

312

Direct Observations of Coherent Backscatter of Radar Waves in Precipitation  

Science Conference Proceedings (OSTI)

In previous work, it was argued that a source of radar coherent scatter occurs in the direction perpendicular to the direction of wave propagation because of the presence of grids of enhanced particle concentrations with spatial periodicities in ...

A. R. Jameson; A. B. Kostinski

2010-09-01T23:59:59.000Z

313

Exploiting temporal coherence in real-time rendering  

Science Conference Proceedings (OSTI)

Temporal coherence (TC), the correlation of contents between adjacent rendered frames, exists across a wide range of scenes and motion types in practical real-time rendering. By taking advantage of TC, we can save redundant computation and improve ...

Daniel Scherzer; Lei Yang; Oliver Mattausch

2010-12-01T23:59:59.000Z

314

Teapot: language support for writing memory coherence protocols  

Science Conference Proceedings (OSTI)

Recent shared-memory parallel computer systems offer the exciting possibility of customizing memory coherence protocols to fit an application's semantics and sharing patterns. Custom protocols have been used to achieve message-passing performance---while ...

Satish Chandra; Brad Richards; James R. Larus

1996-05-01T23:59:59.000Z

315

Comparison of 2- and 10-µm Coherent Doppler Lidar Performance  

Science Conference Proceedings (OSTI)

The performance of 2- and 10-µm coherent Doppler lidar is presented in terms of the statistical distribution of the maximum-likelihood velocity estimator from simulations for fixed range resolution and fixed velocity search space as a function of ...

Rod Frehlich

1995-04-01T23:59:59.000Z

316

Partially Coherent Backscatter in Radar Observations of Precipitation  

Science Conference Proceedings (OSTI)

Classical radar theory only considers incoherent backscatter from precipitation. Can precipitation generate coherent scatter as well? Until now, the accepted answer has been no, because hydrometeors are distributed sparsely in space (relative to ...

A. R. Jameson; A. B. Kostinski

2010-06-01T23:59:59.000Z

317

Processing and Interpretation of Coherent Dual-Polarized Radar Measurements  

Science Conference Proceedings (OSTI)

Dual-polarized coherent radar measurements are used to estimate the differential propagation phase or DP between horizontal and vertical polarization states. The slope of DP is an estimate of the specific differential phase KDP. This process is ...

J. Hubbert; V. Chandrasekar; V. N. Bringi; P. Meischner

1993-04-01T23:59:59.000Z

318

Polaron Coherence Condensation in Layered Colossal Resistive Manganites  

NLE Websites -- All DOE Office Websites (Extended Search)

Polaron Coherence Condensation in Layered Colossal Resistive Manganites Print Polaron Coherence Condensation in Layered Colossal Resistive Manganites Print Novel quantum phenomena, such as high-temperature superconductivity (HTSC) and colossal magnetoresistance (CMR), arise in certain materials where the interactions between electrons are very strong, but the mechanism driving their appearance remains a major puzzle. Now, angle-resolved photoemission findings from an international team led by researchers from Stanford University and the ALS provide the first direct spectroscopic evidence that the transition from insulator to metal in CMR manganese oxides (manganites) results from coherent "polaron condensation." The new findings also suggest that coherence-driven transitions are a generic controlling factor for novel quantum phenomena in doped transition-metal oxides.

319

Lagrangian Coherent Structures near a Subtropical Jet Stream  

Science Conference Proceedings (OSTI)

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

Wenbo Tang; Manikandan Mathur; George Haller; Douglas C. Hahn; Frank H. Ruggiero

2010-07-01T23:59:59.000Z

320

Large-Amplitude Coherent Anomalies in Baroclinic Zonal Flows  

Science Conference Proceedings (OSTI)

In a previous paper the authors developed an asymptotic time-dependent theory for coherent structures on a marginally stable baroclinic flow. It was shown that solitary waves, as well as other more general disturbances of sufficient amplitude, ...

Karl R. Helfrich; Joseph Pedlosky

1995-05-01T23:59:59.000Z

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.


321

Macroscopic coherence between quantum condensates formed at different times  

E-Print Network (OSTI)

We demonstrate macroscopic coherence between quantum condensates generated at different times, separated by more than the particle dephasing time. This is possible due to the dressed light-matter nature of exciton-polaritons, which can be injected resonantly by optical excitation at well-defined momenta. We show that the build-up of coherence between condensates depends on the interaction between the particles, particle density, as well as temperature despite the non-equilibrium nature of the condensate, whereas the mass of the particles plays no role in the condensation of resonantly injected polaritons. This experiment also makes it possible for us to measure directly the large nonlinear phase shift resulting from the polariton-polariton interaction energy. Our results provide direct evidence for coherence between different condensates and demonstrate a new approach for probing their ultrafast dynamics, opening new directions in the study of matter coherence as well as in practical applications such as quantum information and ultrafast logic.

Alex Hayat; Christoph Lange; Lee A. Rozema; Rockson Chang; Shreyas Potnis; Henry M. van Driel; Aephraim M. Steinberg; Mark Steger; David W. Snoke; Loren N. Pfeiffer; Kenneth W. West

2013-09-30T23:59:59.000Z

322

Coherent energy manipulation in single-neutron interferometry  

E-Print Network (OSTI)

We have observed the stationary interference oscillations of a triple-entangled neutron state in an interferometric experiment. Time-dependent interaction with two radio-frequency (rf) fields enables coherent manipulation of an energy degree of freedom in a single neutron. The system is characterized by a multiply entangled state governed by a Jaynes-Cummings Hamiltonian. The experimental results confirm coherence of the manipulation as well as the validity of the description.

S. Sponar; J. Klepp; R. Loidl; S. Filipp; G. Badurek; Y. Hasegawa; H. Rauch

2008-03-25T23:59:59.000Z

323

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

Science Conference Proceedings (OSTI)

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

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

2012-07-01T23:59:59.000Z

324

California | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

February 28, 2003 February 28, 2003 EA-1426: Finding of No Significant Impact Linac Coherent Light Source Project, Stanford Linear Accelerator Center, Menlo Park, California February 3, 2003 EA-1441: Environmental Assessment Construction and Operation of the Molecular Foundry at Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California January 1, 2003 EA-1422: Final Site-wide Environmental Assessment Sandia National Laboratories December 2, 2002 EA-1426: Final Environmental Assessment Linac Coherent Light Source Experimental Facility December 2, 2002 EA-1442: Final Environmental Assessment Proposed Construction and Operation of a Biosafety Level 3 Facility at Lawrence Livermore National Laboratory, Livermore, CA November 1, 2002 EIS-0323: Final Environmental Impact Statement

325

Use of Coherent Transition Radiation to Set Up the APS RF Thermionic Gun to Produce High-Brightness Beams for SASE FEL Experiments  

E-Print Network (OSTI)

We describe use of the Advanced Photon Source (APS) rf thermionic gun, alpha magnet beamline, and linac to produce a stable high-brightness beam in excess of 100 amperes peak current with normalized emittance of 10 pi mm-mrad. To obtain peak currents greater than 100 amperes, the rf gun system must be tuned to produce a FWHM bunch length on the order of 350 fs. Bunch lengths this short are measured using coherent transition radiation (CTR) produced when the rf gun beam, accelerated to 40 MeV, strikes a metal foil. The CTR is detected using a Golay detector attached to one arm of a Michelson interferometer. The alpha magnet current and gun rf phase are adjusted so as to maximize the CTR signal at the Golay detector, which corresponds to the minimum bunch length. The interferometer is used to measure the autocorrelation of the CTR radiation. The minimum phase approximation is used to derive the bunch profile from the autocorrelation. The high-brightness beam is accelerated to 217 MeV and used to produce SASE in...

Sereno, N S; Lumpkin, Alex H; Sereno, Nicholas; Borland, Michael; Lumpkin, Alex

2000-01-01T23:59:59.000Z

326

USE OF COHERENT TRANSITION RADIATION TO SET UP THE APS RF THERMIONIC GUN TO PRODUCE HIGH-BRIGHTNESS BEAMS FOR SASE FEL EXPERIMENTS ?  

E-Print Network (OSTI)

We describe use of the Advanced Photon Source (APS) rf thermionic gun [1], alpha-magnet beamline, and linac [2] to produce a stable high-brightness beam in excess of 100 amperes peak current with normalized emittance of 10 ? mm-mrad. To obtain peak currents greater than 100 amperes, the rf gun system must be tuned to produce a FWHM bunch length on the order of 350 fs. Bunch lengths this short are measured using coherent transition radiation (CTR) produced when the rf gun beam, accelerated to 40 MeV, strikes a metal foil. The CTR is detected using a Golay detector attached to one arm of a Michelson interferometer. The alpha-magnet current and gun rf phase are adjusted so as to maximize the CTR signal at the Golay detector, which corresponds to the minimum bunch length. The interferometer is used to measure the autocorrelation of the CTR. The minimum phase approximation [3] is used to derive the bunch profile from the autocorrelation. The high-brightness beam is accelerated to 217 MeV and used to produce self-amplified spontaneous emission (SASE) in five APS undulators installed in the Low- Energy Undulator Test Line (LEUTL) experiment hall [4]. Initial optical measurements showed a gain length of 1.3 m at 530 nm. 1

unknown authors

2000-01-01T23:59:59.000Z

327

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

E-Print Network (OSTI)

Nuclear Data Measurements at the RPI LINAC Y. Danon, R.C. Block, R. Bahran, M. Rapp, F. Saglime, C are used for a variety of experiments primarily related to nuclear data measurements. Neutron targets) at RPI was built as a pulsed neutron source designed for nuclear data measurements [ 1 ]. The facility

Danon, Yaron

328

Proximity coherence for chip-multiprocessors  

E-Print Network (OSTI)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 6.3.1 Impact on Memory Latency . . . . . . . . . . . . . . . . . . . . . . . . . . 117 6.3.2 Invalidation Chain Length . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 6.3.3 Proximity Hit Rate... PCI x 2 PCI x 2 DRAM D/A DRAM DRAM DRAM DRAM C S C S C S C S C S C S C S C S C S C S C S C S C S C S C S C S Compute Pipeline SMEM PC X DATA CACHEPC IMEM DRAM D RAM D RAM DRAM D RAM D RAM IF RFD A TL M1 F P E U WB r26 r27 r25 r24 Input FIFOs from...

Barrow-Williams, Nick

2011-11-08T23:59:59.000Z

329

Atomic Frequency standards Based on Pulsed Coherent Light Storage  

E-Print Network (OSTI)

We propose a new scheme of microwave frequency standards based on pulsed coherent optical information storage. Unlike the usual frequency reference where the Ramsey fringe is printed on the population of a certain state, we print the Ramsey fringe on the coherence. Then the coherence is detected in the form of a retrieval light. The central line of the Ramsey fringe can be used as a frequency reference in an absorption-cell-based atomic frequency standard. This scheme is free of light shifts as the interrogating process is separated from the optical pumping processes, and the cavity pulling effect is negligible due to the low Q requirement. Encoding the Ramsey interference into the retrieval light pulse has the merit of high signal to noise ratio and the estimated frequency stability of shot noise limit is about $2\\times10^{-14}$ in 1 second, this scheme is promising for building small, compact and stable atomic frequency standards.

Yan, Bo; Wang, Yuzhu

2008-01-01T23:59:59.000Z

330

Transverse Coherence of the LCLS X-Ray Beam  

Science Conference Proceedings (OSTI)

Self-amplifying spontaneous radiation free-electron lasers, such as the LCLS or the European X-FEL, rely on the incoherent, spontaneous radiation as the seed for the amplifying process. Though this method overcomes the need for an external seed source one drawback is the incoherence of the effective seed signal. The FEL process allows for a natural growth of the coherence because the radiation phase information is spread out within the bunch due to slippage and diffraction of the radiation field. However, at short wavelengths this spreading is not sufficient to achieve complete coherence. In this presentation we report on the results of numerical simulations of the LCLS X-ray FEL. From the obtained radiation field distribution the coherence properties are extracted to help to characterize the FEL as a light source.

Not Available

2010-12-01T23:59:59.000Z

331

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

332

Observation of Coherence in the Photosystem II Reaction Center  

E-Print Network (OSTI)

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

Fuller, Franklin D; Senlik, S Seckin; Wilcox, Daniel E; Ogilvie, Jennifer P

2013-01-01T23:59:59.000Z

333

Targeted coherent search for gravitational waves from compact binary coalescences  

SciTech Connect

We introduce a method for conducting a targeted, coherent search for compact binary coalescences. The search is tailored to be used as a follow-up to electromagnetic transients such as gamma-ray bursts. We derive the coherent search statistic for Gaussian detector noise and discuss the benefits of a coherent, multidetector search over coincidence methods. To mitigate the effects of nonstationary data, we introduce a number of signal consistency tests, including the null signal-to-noise ratio, amplitude consistency, and several {chi}{sup 2} tests. We demonstrate the search performance on Gaussian noise and on data from LIGO's fourth science run and verify that the signal consistency tests are capable of removing the majority of noise transients, giving the search an efficiency comparable to that achieved in Gaussian noise.

Harry, I. W.; Fairhurst, S. [School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff, CF24 3AA (United Kingdom)

2011-04-15T23:59:59.000Z

334

Direct three-dimensional coherently scattered x-ray microtomography  

Science Conference Proceedings (OSTI)

Purpose: It has been shown that coherently scattered x rays can be used to discriminate and identify specific components in a mixture of low atomic weight materials. The authors demonstrated a new method of doing coherently scattered x-ray tomography with a thin sheet of x ray. Methods: A collimated x-ray fan-beam, a parallel polycapillary collimator, and a phantom consisting of several biocompatible materials of low attenuation-based contrast were used to investigate the feasibility of the method. Because of the particular experimental setup, only the phantom translation perpendicular to the x-ray beam is needed and, thus, there is no need of Radon-type tomographic reconstruction, except for the correction of the attenuation to the primary and scattered x rays, which was performed by using a conventional attenuation-based tomographic image data set. The coherent scatter image contrast changes with momentum transfer among component materials in the specimen were investigated with multiple x-ray sources with narrow bandwidth spectra generated with anode and filter combinations of Cu/Ni (8 keV), Mo/Zr (18 keV), and Ag/Pd (22 keV) and at multiple scatter angles by orienting the detector and polycapillary collimator at different angles to the illuminating x ray. Results: The contrast among different materials changes with the x-ray source energy and the angle at which the image was measured. The coherent scatter profiles obtained from the coherent scatter images are consistent with the published results. Conclusions: This method can be used to directly generate the three-dimensional coherent scatter images of small animal, biopsies, or other small objects with low atomic weight biological or similar synthetic materials with low attenuation contrast. With equipment optimized, submillimeter spatial resolution may be achieved.

Cui Congwu; Jorgensen, Steven M.; Eaker, Diane R.; Ritman, Erik L. [Department of Medical Physics, CancerCare Manitoba, 675 McDermot Avenue, Winnipeg, Manitoba R3E 0V9 (Canada); Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street Southwest, Alfred Building 2-409, Rochester, Minnesota 55905 (United States)

2010-12-15T23:59:59.000Z

335

Generating polarization controllable FELs at Dalian coherent light source  

E-Print Network (OSTI)

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

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

2013-01-01T23:59:59.000Z

336

Quatum Thermodynamics and the coherence in Ion channels  

E-Print Network (OSTI)

We showed that quantum mechanical superposition can sustain in the process of ion transfer in protein membrane for a substantial period, in spite of the presence of the interactions with environmental modes of molecular vibration. The spectral temperature, as defined in quantum thermodynamical framework plays a significant role in maintaining the coherence. The ratio of decoherence time and dwell time has been calculated, which can be directly related to the degree of coherence. The results shead new light to build quantum information system of entangled ionic states in the voltage gated biological channels.

Samyadeb Bhattacharya; Sisir Roy

2013-03-08T23:59:59.000Z

337

Efficiency of excitation transfer in photosynthesis under quantum coherence  

E-Print Network (OSTI)

We investigate the role of quantum coherence in the efficiency of excitation transfer in a spin-star arrangement of interacting two-level systems, mimicking a light-harvesting antenna connected to a reaction center, similar to a photosynthetic system in nature. By using the quantum jump approach, we show that the efficiency depends intimately on the quantum interference among states in which the excitation is localized on individual sites in the antenna. Our results indicate how efficiency may be used as an indication of quantum coherence in energy transfer.

Olaya-Castro, Alexandra; Fassioli-Olsen, Francesca; Johnson, Neil F

2007-01-01T23:59:59.000Z

338

Quantum Coherence Conservation by Growth in Environmental Dissipation Rate  

E-Print Network (OSTI)

Quantum coherence conservation is shown to be achieved by a very high rate of dissipation of an environmental system coupled with a principal system. This effect is not in the list of previously-known strategies of noise suppression, such as Zeno effect, dynamical decoupling, quantum error correction code, and decoherence free subspace. An analytical solution is found for a simplified model of a single qubit coupled with an environmental single qubit dissipating rapidly. We also show examples of coherence conservation in a spin-boson linear coupling model with a numerical evaluation.

Akira SaiToh; Robabeh Rahimi; Mikio Nakahara

2007-09-05T23:59:59.000Z

339

Simultaneous Measurement of Ocean Winds and Waves with an Airborne Coherent Real Aperture Radar  

Science Conference Proceedings (OSTI)

A coherent, X-band airborne radar has been developed to measure wind speed and direction simultaneously with directional wave spectra on the ocean. The coherent real aperture radar (CORAR) measures received power, mean Doppler shifts, and mean ...

William J. Plant; William C. Keller; Kenneth Hayes

2005-07-01T23:59:59.000Z

340

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

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

Minimum Uncertainty, Coherence and Squeezing in Diffusion Processes, and Stochastic Quantization  

E-Print Network (OSTI)

We show that uncertainty relations, as well as minimum uncertainty coherent and squeezed states, are structural properties for diffusion processes. Through Nelson stochastic quantization we derive the stochastic image of the quantum mechanical coherent and squeezed states.

Salvatore De Martino; Silvio De Siena; Fabrizio Illuminati; Giuseppe Vitiello

1993-10-18T23:59:59.000Z

342

Coherent resonant tunneling through an artificial molecule C. A. Stafford  

E-Print Network (OSTI)

Coherent resonant tunneling through an artificial molecule C. A. Stafford Fakulta¨t fu¨r Physik PRB 58C. A. STAFFORD, R. KOTLYAR, AND S. DAS SARMA #12;Coulomb blockade12 for C Cg to a ballistic /e 1 follows from the particle-hole symmetry of Eq. 1 . 7094 PRB 58C. A. STAFFORD, R. KOTLYAR, AND S

Stafford, Charles

343

Coherent. pi. /sup 0/ photoproduction at intermediate energy  

SciTech Connect

Coherent ..pi../sup 0/ photoproduction from nuclei is calculated in the ..delta..-hole framework. Important background production terms are included, and a comparison with data is presented. Sensitivity to various aspects of the dynamics, such as recoil and the ..delta.. spreading potential, are examined.

Koch, J.H.; Moniz, E.J.

1983-02-01T23:59:59.000Z

344

Wind-Field Coherence and Its Variations over West Africa  

Science Conference Proceedings (OSTI)

The wind-field coherence over West Africa is investigated during two contrasted periods, 1953–63 (abnormally wet) and 1963-75 (abnormally dry) in the Sahel. Zonal and meridional components of the monthly mean wind are computed with radiosonde ...

Bernard Fontaine; Serge Janicot

1992-05-01T23:59:59.000Z

345

Cohomological invariants of coherent sheaves over projective schemes - a survey  

E-Print Network (OSTI)

Abstract. We give a survey on certain results related to the cohomology of projective schemes with coefficients in coherent sheaves. In particular we present results on cohomological patterns, cohomological Hilbert functions and cohomological Hilbert polynomials. Bounding results for Castelnuovo-Mumford regularities, Severi coregularities and cohomological postulation numbers are discussed. Moreover, a number of open questions is presented.

M. Brodmann; Cohomological Hilbert Functions

2001-01-01T23:59:59.000Z

346

Coherent Eddies in the Labrador Sea Observed from a Mooring  

Science Conference Proceedings (OSTI)

During June–November 1994, a mooring in the central Labrador Sea near the former Ocean Weather Station Bravo recorded a half-dozen anomalous events that prove to be two different types of coherent eddies. Comparisons with simple analytical models ...

Jonathan M. Lilly; Peter B. Rhines

2002-02-01T23:59:59.000Z

347

Wave-coherent airflow and critical layers over ocean waves  

Science Conference Proceedings (OSTI)

An analysis of coherent measurements of winds and waves from data collected during the ONR HiRes program from R/P FLIP off the coast of northern California in June 2010 is presented. A suite of wind and wave measuring systems was deployed to ...

Laurent Grare; Luc Lenain; W. Kendall Melville

348

Neutron Form Factor from Neutrino-Nucleus Coherent Elastic Scattering  

E-Print Network (OSTI)

We analyze the prospect of measuring the neutron form factor of a nucleus through the detection of neutrino-nucleus coherent elastic scattering. We predict numbers of events in a liquid noble nuclear recoil detector at a stopped pion neutrino source. We discuss the precision required to distinguish between different theoretical models for the form factor.

Philip S. Amanik; Gail C. McLaughlin

2007-07-27T23:59:59.000Z

349

Interactive watercolor rendering with temporal coherence and abstraction  

Science Conference Proceedings (OSTI)

This paper presents an interactive watercolor rendering technique that recreates the specific visual effects of lavis watercolor. Our method allows the user to easily process images and 3d models and is organized in two steps: an abstraction step that ... Keywords: abstraction, non-photorealistic rendering, temporal coherence, watercolor

Adrien Bousseau; Matt Kaplan; Joëlle Thollot; François X. Sillion

2006-06-01T23:59:59.000Z

350

Pulse-to-Pulse Coherent Doppler Sonar Signal Processing Techniques  

Science Conference Proceedings (OSTI)

In this paper we present and discuss techniques for the computation of the mean and spectral variance of a pulse-to-pulse coherent sonar signal, leading to the measurement of mean water velocity and turbulence. The use of an autocovariance ...

Roger Lhermitte; Robert Serafin

1984-12-01T23:59:59.000Z

351

Atmospheric Lagrangian coherent structures considering unresolved turbulence and forecast uncertainty  

E-Print Network (OSTI)

Atmospheric Lagrangian coherent structures considering unresolved turbulence and forecast, the uncertainty of the forecast FTLE fields is analyzed using ensemble forecasting. Unavoidable errors of the forecast velocity data due to the chaotic dynamics of the atmosphere is the salient reason for errors

Ross, Shane

352

Coherent spin control by electrical manipulation of the magnetic anisotropy  

E-Print Network (OSTI)

High-spin paramagnetic manganese defects in polar piezoelectric zinc oxide exhibit a simple almost axial anisotropy and phase coherence times of the order of a millisecond at low temperatures. The anisotropy energy is tunable using an externally applied electric field. This can be used to control electrically the phase of spin superpositions and to drive spin transitions with resonant microwave electric fields.

Richard E George; James P Edwards; Arzhang Ardavan

2012-09-12T23:59:59.000Z

353

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

354

Non-Markovian decoherence dynamics of entangled coherent states  

Science Conference Proceedings (OSTI)

We microscopically model the decoherence dynamics of entangled coherent states of twooptical modes under the influence of vacuum fluctuation. We derive an exact masterequation with time-dependent coefficients reflecting the memory effect of the environ-ment, ... Keywords: decoherence theory, exact master equation, non-Markovian dynamics

Jun-Hong An; Mang Feng; Wei-Min Zhang

2009-03-01T23:59:59.000Z

355

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

SciTech Connect

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

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

2011-04-20T23:59:59.000Z

356

Coherence-Centric Logging and Recovery for Home-Based Software Distributed Shared Memory  

E-Print Network (OSTI)

Coherence-Centric Logging and Recovery for Home-Based Software Distributed Shared Memory Angkul, called the coherence-centric logging (CCL) and re- covery protocol, for home-based SDSM. Our CCL mini access latency by overlapping disk accesses with coherence-induced com- munication existing in home-based

Tzeng, Nian-Feng

357

Analysis of cache-coherence bottlenecks with hybrid hardware/software techniques  

Science Conference Proceedings (OSTI)

Application performance on high-performance shared-memory systems is often limited by sharing patterns resulting in cache-coherence bottlenecks. Current approaches to identify coherence bottlenecks incur considerable run-time overhead and do not scale. ... Keywords: Hardware performance monitoring, SMPs, cache analysis, coherence protocols, dynamic binary rewriting, program instrumentation

Jaydeep Marathe; Frank Mueller; Bronis R. de Supinski

2006-12-01T23:59:59.000Z

358

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

SciTech Connect

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

Kim, C.H.

1987-04-01T23:59:59.000Z

359

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

2012-12-20T23:59:59.000Z

360

A new type of bunch compressor and seeding of a short-wavelength coherent radiation.  

Science Conference Proceedings (OSTI)

Transverse-to-longitudinal emittance exchange was proposed in [1] as a tool for an effective matching of the electron beam phase space to requirements of a possible application. Here we propose a new purpose, namely, use of two consecutive emittance exchanges equipped with the telescope between them for a bunch compression that can be done without the energy chirp in the electron bunch. In principle it allows to reduce the electron peak current in the linac by moving the bunch compressor to the end of the linac and, thus, to relax collective effects associated with high peak currents. It is also possible to have a split-action compression when the first part is done inside the low-energy part of the linac and the second and final part is done after the linac. We also demonstrate how proposed bunch compressor can be used for frequency up-conversion of the energy modulation provided by the laser interacting with the electron beam and thus can prepare a significantly higher frequency seed for seeded free-electron lasers. The same approach can be used for a frequency down-conversion that can be useful for generation of THz radiation.

Zholents, A. A.; Zolotorev, M. S. (Accelerator Systems Division (APS)); (LBNL)

2011-05-30T23:59:59.000Z

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

SLAC National Accelerator Laboratory - Ultrafast Lasers at the...  

NLE Websites -- All DOE Office Websites (Extended Search)

Lasers at the Linac Coherent Light Source By Alan Fry, LCLS Laser Group July 5, 2011 The Linac Coherent Light Source at SLAC is the world's first hard X-ray free-electron laser, or...

362

Resonant Regimes in the Fock-Space Coherence of Multilevel Quantum Dots  

E-Print Network (OSTI)

The coherence between quantum states with different particle numbers --- the Fock-space coherence --- qualitatively differs from the more common Hilbert-space coherence between states with equal particle numbers. For a quantum dot with multiple channels available for transport, we find the conditions for decoupling the dynamics of the Fock-space coherence from both the Hilbert-space coherence as well as the population dynamics. We further find specific energy and coupling regimes where a long-lived resonance in the Fock-space coherence of the system is realized, even where no resonances are found either in the populations or Hilbert-space coherence. Numerical calculations show this resonance remains robust in the presence of both boson-mediated relaxation and transport through the quantum dot.

Eduardo Vaz; Jordan Kyriakidis

2011-05-26T23:59:59.000Z

363

Apparatus for generating coherent infrared energy of selected wavelength  

SciTech Connect

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

364

Coherence of an optically illuminated single nuclear spin qubit  

E-Print Network (OSTI)

We investigate the coherence properties of individual nuclear spin quantum bits in diamond [Dutt et al., Science, 316, 1312 (2007)] when a proximal electronic spin associated with a nitrogen-vacancy (NV) center is being interrogated by optical radiation. The resulting nuclear spin dynamics are governed by time-dependent hyperfine interaction associated with rapid electronic transitions, which can be described by a spin-fluctuator model. We show that due to a process analogous to motional averaging in nuclear magnetic resonance, the nuclear spin coherence can be preserved after a large number of optical excitation cycles. Our theoretical analysis is in good agreement with experimental results. It indicates a novel approach that could potentially isolate the nuclear spin system completely from the electronic environment.

Liang Jiang; M. V. Gurudev Dutt; Emre Togan; Lily Childress; Paola Cappellaro; Jacob M. Taylor; Mikhail D. Lukin

2007-07-09T23:59:59.000Z

365

Development of coherent Raman measurements of temperature in condensed phases  

SciTech Connect

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

Mcgrane, Shawn D [Los Alamos National Laboratory; Dang, Nhan C [Los Alamos National Laboratory; Bolme, Cindy A [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory

2010-12-08T23:59:59.000Z

366

Probing mechanical quantum coherence with an ultracold-atom meter  

Science Conference Proceedings (OSTI)

We propose a scheme to probe quantum coherence in the state of a nanocantilever based on its magnetic coupling (mediated by a magnetic tip) with a spinor Bose Einstein condensate (BEC). By mapping the BEC into a rotor, its coupling with the cantilever results in a gyroscopic motion whose properties depend on the state of the cantilever: the dynamics of one of the components of the rotor angular momentum turns out to be strictly related to the presence of quantum coherence in the state of the cantilever. We also suggest a detection scheme relying on Faraday rotation, which produces only a very small back-action on the BEC and is thus suitable for a continuous detection of the cantilever's dynamics.

Lo Gullo, N.; Busch, Th. [Department of Physics, University College Cork, Cork (Ireland); Palma, G. M. [NEST Istituto Nanoscienze-CNR and Dipartimento di Fisica, Univerisita' degli Studi di Palermo, Via Archirafi 36, I-90123 Palermo (Italy); Paternostro, M. [Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Queen's University, Belfast BT7 1NN (United Kingdom)

2011-12-15T23:59:59.000Z

367

Coherent manipulation of atomic qubits in optical micropotentials  

E-Print Network (OSTI)

We experimentally demonstrate the coherent manipulation of atomic states in far-detuned dipole traps and registers of dipole traps based on two-dimensional arrays of microlenses. By applying Rabi, Ramsey, and spin-echo techniques, we systematically investigate the dephasing mechanisms and determine the coherence time. Simultaneous Ramsey measurements in up to 16 dipole traps are performed and proves the scalability of our approach. This represents an important step in the application of scalable registers of atomic qubits for quantum information processing. In addition, this system can serve as the basis for novel atomic clocks making use of the parallel operation of a large number of individual clocks each remaining separately addressable.

A. Lengwenus; J. Kruse; M. Volk; W. Ertmer; G. Birkl

2007-02-09T23:59:59.000Z

368

Emission of coherent THz-radiation from superconductors.  

Science Conference Proceedings (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

369

Holographic entanglement and causal information in coherent states  

E-Print Network (OSTI)

Scalar solitons in global AdS4 are holographically dual to coherent states carrying a non-trivial condensate of a scalar operator. We study the holographic information content of these states, focusing on a particular spatial region, by examining the entanglement entropy and causal holographic information. We show generically that whenever the dimension of the condensed operator is sufficiently low (characterized by the double-trace operator becoming relevant), such coherent states have lower entanglement and causal holographic information than the vacuum state of the system, despite having greater energy. We also use these geometries to illustrate the fact that causal wedges associated with a simply-connected boundary region can have non-trivial topology even in causally trivial spacetimes.

Simon A. Gentle; Mukund Rangamani

2013-10-31T23:59:59.000Z

370

From cardinal spline wavelet bases to highly coherent dictionaries  

E-Print Network (OSTI)

Wavelet families arise by scaling and translations of a prototype function, called the {\\em {mother wavelet}}. The construction of wavelet bases for cardinal spline spaces is generally carried out within the multi-resolution analysis scheme. Thus, the usual way of increasing the dimension of the multi-resolution subspaces is by augmenting the scaling factor. We show here that, when working on a compact interval, the identical effect can be achieved without changing the wavelet scale but reducing the translation parameter. By such a procedure we generate a redundant frame, called a {\\em{dictionary}}, spanning the same spaces as a wavelet basis but with wavelets of broader support. We characterise the correlation of the dictionary elements by measuring their `coherence' and produce examples illustrating the relevance of highly coherent dictionaries to problems of sparse signal representation.

Andrle, Miroslav

2008-01-01T23:59:59.000Z

371

Economic impact  

Science Conference Proceedings (OSTI)

In federal fiscal year 2000 (FY00), Berkeley Lab had 4,347 full- and part-time employees. In addition, at any given time of the year, there were more than 1,000 Laboratory guests. These guests, who also reside locally, have an important economic impact on the nine-county Bay Area. However, Berkeley Lab's total economic impact transcends the direct effects of payroll and purchasing. The direct dollars paid to the Lab's employees in the form of wages, salaries, and benefits, and payments made to contractors for goods and services, are respent by employees and contractors again and again in the local and greater economy. Further, while Berkeley Lab has a strong reputation for basic scientific research, many of the Lab's scientific discoveries and inventions have had direct application in industry, spawning new businesses and creating new opportunities for existing firms. This analysis updates the Economic Impact Analysis done in 1996, and its purpose is to describe the economic and geographic impact of Laboratory expenditures and to provide a qualitative understanding of how Berkeley Lab impacts and supports the local community. It is intended as a guide for state, local, and national policy makers as well as local community members. Unless otherwise noted, this analysis uses data from FY00, the most recent year for which full data are available.

Technology Transfer Department

2001-06-01T23:59:59.000Z

372

Optimal design and quantum benchmarks for coherent state amplifiers  

E-Print Network (OSTI)

We establish the ultimate quantum limits to the amplification of an unknown coherent state, both in the deterministic and probabilistic case, investigating the realistic scenario where the expected photon number is finite. In addition, we provide the benchmark that experimental realizations have to surpass in order to beat all classical amplification strategies and to demonstrate genuine quantum amplification. Our result guarantees that a successful demonstration is in principle possible for every finite value of the expected photon number.

Giulio Chiribella; Jinyu Xie

2013-01-07T23:59:59.000Z

373

Quantum interferometry using coherent beam stimulated parametric down-conversion  

E-Print Network (OSTI)

We show how stimulated parametric processes can be employed in experiments on beyond the diffraction limit to overcome the problem of low visibility obtained by using spontaneous down conversion operating in the high gain regime. We further show enhancement of the count rate by several orders when stimulated parametric processes are used. Both the two photon counts and the visibility can be controlled by the phase of the stimulating coherent beam.

Aziz Kolkiran; G. S. Agarwal

2008-05-05T23:59:59.000Z

374

Ultrarelativistic laser systems based on coherent beam combining  

Science Conference Proceedings (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

375

External Time-Varying Fields and Electron Coherence  

E-Print Network (OSTI)

The effect of time-varying electromagnetic fields on electron coherence is investigated. A sinusoidal electromagnetic field produces a time varying Aharonov-Bohm phase. In a measurement of the interference pattern which averages over this phase, the effect is a loss of contrast. This is effectively a form of decoherence. We calculate the magnitude of this effect for various electromagnetic field configurations. The result seems to be sufficiently large to be observable.

Jen-Tsung Hsiang; L. H. Ford

2004-02-03T23:59:59.000Z

376

Simulation study of electron response amplification in coherent electron cooling  

Science Conference Proceedings (OSTI)

In Coherent Electron Cooling (CEC), it is essential to study the amplification of electron response to a single ion in the FEL process, in order to proper align the electron beam and the ion beam in the kicker to maximize the cooling effect. In this paper, we use Genesis to simulate the amplified electron beam response of single ion in FEL amplification process, which acts as Green's function of the FEL amplifier.

Hao Y.; Litvinenko, V.N.

2012-05-20T23:59:59.000Z

377

Resonant excitation of coherent Cerenkov radiation in dielectric lined waveguides  

Science Conference Proceedings (OSTI)

We report the observation of coherent Cerenkov radiation in the terahertz regime emitted by a relativistic electron pulse train passing through a dielectric lined cylindrical waveguide. We describe the beam manipulations and measurements involved in repetitive pulse train creation including comb collimation and nonlinear optics corrections. With this technique, modes beyond the fundamental are selectively excited by use of the appropriate frequency train. The spectral characterization of the structure shows preferential excitation of the fundamental and of a higher longitudinal mode.

Andonian, G.; Williams, O.; Wei, X.; Niknejadi, P.; Hemsing, E.; Rosenzweig, J. B. [Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California 90095 (United States); Muggli, P. [University of Southern California, Los Angeles, California 90089 (United States); Babzien, M.; Fedurin, M.; Kusche, K.; Malone, R.; Yakimenko, V. [Accelerator Test Facility, Brookhaven National Laboratory, Upton, New York 11973 (United States)

2011-05-16T23:59:59.000Z

378

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

2010-12-23T23:59:59.000Z

379

Capacity with energy constraint in coherent state channel  

E-Print Network (OSTI)

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

Masahito Hayashi

2009-04-02T23:59:59.000Z

380

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

NLE Websites -- All DOE Office Websites (Extended Search)

Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Researchers at Berkeley Lab have been exploring the ways coherent synchrotron radiation (CSR) is generated in electron storage rings when femtosecond lasers are used to carve out ultrafast x-ray pulses by femtoslicing (see "Tailored Terahertz Pulses from a Laser-Modulated Electron Beam"). In their most recent work, the researchers reported the first observation of seeding an instability of the electron beam by the laser, and they presented a physical model that shows how this occurs under the proper conditions. Such a mechanism makes it possible to control the instability onset and to exploit its gain for the generation of pulses of terahertz CSR of unprecedented power. Terahertz radiation with a wavelength from about 1 cm to about 100 microns between the microwave and the infrared would provide access to a large number of fundamental phenomena. To mention only some of them: excited electrons orbit, small molecules rotate, proteins vibrate, superconducting energy gaps resonate, and gaseous and solid-state plasmas oscillate at terahertz frequencies. But generating terahertz radiation is ordinarily a challenging task for any kind of source, including storage-ring-based synchrotron light sources. The new findings by the ALS group could represent a significant step toward satisfying the need for powerful terahertz sources.

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

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

NLE Websites -- All DOE Office Websites (Extended Search)

Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Researchers at Berkeley Lab have been exploring the ways coherent synchrotron radiation (CSR) is generated in electron storage rings when femtosecond lasers are used to carve out ultrafast x-ray pulses by femtoslicing (see "Tailored Terahertz Pulses from a Laser-Modulated Electron Beam"). In their most recent work, the researchers reported the first observation of seeding an instability of the electron beam by the laser, and they presented a physical model that shows how this occurs under the proper conditions. Such a mechanism makes it possible to control the instability onset and to exploit its gain for the generation of pulses of terahertz CSR of unprecedented power. Terahertz radiation with a wavelength from about 1 cm to about 100 microns between the microwave and the infrared would provide access to a large number of fundamental phenomena. To mention only some of them: excited electrons orbit, small molecules rotate, proteins vibrate, superconducting energy gaps resonate, and gaseous and solid-state plasmas oscillate at terahertz frequencies. But generating terahertz radiation is ordinarily a challenging task for any kind of source, including storage-ring-based synchrotron light sources. The new findings by the ALS group could represent a significant step toward satisfying the need for powerful terahertz sources.

382

Coherent backscattering in nonlinear atomic media: quantum Langevin approach  

E-Print Network (OSTI)

In this theoretical paper, we investigate coherence properties of the near-resonant light scattered by two atoms exposed to a strong monochromatic field. To properly incorporate saturation effects, we use a quantum Langevin approach. In contrast to the standard optical Bloch equations, this method naturally provides the inelastic spectrum of the radiated light induced by the quantum electromagnetic vacuum fluctuations. However, to get the right spectral properties of the scattered light, it is essential to correctly describe the statistical properties of these vacuum fluctuations. Because of the presence of the two atoms, these statistical properties are not Gaussian : (i) the spatial two-points correlation function displays a speckle-like behavior and (ii) the three-points correlation function does not vanish. We also explain how to incorporate in a simple way propagation with a frequency-dependent scattering mean-free path, meaning that the two atoms are embedded in an average scattering dispersive medium. Finally we show that saturation-induced nonlinearities strongly modify the atomic scattering properties and, as a consequence, provide a source of decoherence in multiple scattering. This is exemplified by considering the coherent backscattering configuration where interference effects are blurred by this decoherence mechanism. This leads to a decrease of the so-called coherent backscattering enhancement factor.

Beno{\\^?}t Gr{é}maud}; Thomas Wellens; Dominique Delande; Christian Miniatura

2005-06-01T23:59:59.000Z

383

The Scalable Coherent Interface and related standards projects  

SciTech Connect

The Scalable Coherent Interface (SCI) project (IEEE P1596) found a way to avoid the limits that are inherent in bus technology. SCI provides bus-like services by transmitting packets on a collection of point-to-point unidirectional links. The SCI protocols support cache coherence in a distributed-shared-memory multiprocessor model, message passing, I/O, and local-area-network-like communication over fiber optic or wire links. VLSI circuits that operate parallel links at 1000 MByte/s and serial links at 1000 Mbit/s will be available early in 1992. Several ongoing SCI-related projects are applying the SCI technology to new areas or extending it to more difficult problems. P1596.1 defines the architecture of a bridge between SCI and VME; P1596.2 compatibly extends the cache coherence mechanism for efficient operation with kiloprocessor systems; P1596.3 defines new low-voltage (about 0.25 V) differential signals suitable for low power interfaces for CMOS or GaAs VLSI implementations of SCI; P1596.4 defines a high performance memory chip interface using these signals; P1596.5 defines data transfer formats for efficient interprocessor communication in heterogeneous multiprocessor systems. This paper reports the current status of SCI, related standards, and new projects. 16 refs.

Gustavson, D.B.

1991-09-01T23:59:59.000Z

384

Obtaining attosecond X-ray pulses using a self-amplified spontaneous emission free electron laser  

E-Print Network (OSTI)

A 429, 243 (1999). [18] LCLS Design Study Group, ReportLinac Coherent Light Source (LCLS) [18], except the electron

Zholents, A.A.; Penn, G.

2005-01-01T23:59:59.000Z

385

ALS Activity Report 2004  

E-Print Network (OSTI)

Kirkpatrick-Baez LCLS . . . . . . . .Linac Coherent Lightthe experimental program at the LCLS, an x-ray free-electron

Tamura Ed., Lori S.

2005-01-01T23:59:59.000Z

386

TAO: Impact  

NLE Websites -- All DOE Office Websites (Extended Search)

Impact Impact Home Download Documentation Publications Referencing TAO Impact Who We Are Acknowledgements License Contact Us Research and Publications that make use of TAO Dressed TDDFT study of low-lying electronic excited states in selected linear polyenes and diphenylopolyenes, Mazur, G., Makowski, M., Włodarczyk, R., and Aoki, Y., International Journal of Quantum Chemistry, 111, 4, 819--825, 2011. BibTeX Secondary thermal cracks in EGS: a variational approach, Bourdin, B., Knepley, M., and Maurini, C., Proceedings of the 34th annual meeting of the Geothermal resources council, 2010. BibTeX Adaptive Real-Time Bioheat Transfer Models for Computer Driven MR-guided Laser Induced Thermal Therapy, Fuentes, D., Feng, Y., Elliott, A., Shetty, A., McNichols, R. J., Oden, J. T., and Stafford, R. J., IEEE Trans. Biomed. Eng., 5, 1024--1030, 2010. BibTeX

387

Center for Beam Physics  

E-Print Network (OSTI)

Brookhaven). We have joined the LCLS (Linac Coherent LightCoherent Light Source (LCLS) project. A major new activityplaya leading role in the LCLS collaboration in the theory/

Chattopadhyay, S.

2010-01-01T23:59:59.000Z

388

Observation of coherence revival and fidelity saturation in a delta-kicked rotor potential  

E-Print Network (OSTI)

We experimentally investigate the effect of atomic delta-kicked rotor potentials on the mutual coherence between wavepackets in an atom interferometer. The differential action of the kicked rotor degrades the mutual coherence, leading to a reduction of the interferometry fringe visibility; however, when the repetition rate of the kicked rotor is at or near the quantum resonance, we observe revival of matter-wave coherence as the number of kicks increases, resulting in non-vanishing coherence in the large kick number limit. This coherence saturation effect reflects a fidelity saturation in phase-space displacement echoes in deep quantum regime. The saturation effect is accompanied with an invariant distribution of matter-wave coherence under the kicked rotor perturbations.

Wu, Saijun; Prentiss, Mara G

2008-01-01T23:59:59.000Z

389

Observation of coherence revival and fidelity saturation in a delta-kicked rotor potential  

E-Print Network (OSTI)

We experimentally investigate the effect of atomic $\\delta$-kicked rotor potentials on the mutual coherence between wavepackets in an atom interferometer. The differential action of the kicked rotor degrades the mutual coherence, leading to a reduction of the interferometry fringe visibility; however, when the repetition rate of the kicked rotor is at or near the quantum resonance, we observe revival of matter-wave coherence as the number of kicks increases, resulting in non-vanishing coherence in the large kick number limit. This coherence saturation effect reflects a saturation of fidelity decay due to momentum displacements in deep quantum regime. The saturation effect is accompanied with an invariant distribution of matter-wave coherence under the kicked rotor perturbations.

Saijun Wu; Alexey Tonyushkin; Mara G. Prentiss

2008-01-03T23:59:59.000Z

390

The Nature of Quantum States Created by One Photon Absorption: Pulsed Coherent vs. Pulsed Incoherent Light  

E-Print Network (OSTI)

We analyze electronically excited nuclear wave functions and their coherence when subjecting a molecule to the action of natural, pulsed incoherent solar-like light, and to that of ultrashort coherent light assumed to have the same center frequencies and spectral bandwidths. Specifically, we compute the spatio-temporal dependence of the excited wave packets and their electronic coherence for these two types of light sources, on different electronic potential energy surfaces. The resultant excited state wave functions are shown to be qualitatively different, reflecting the light source from which they originated. In addition, electronic coherence is found to decay significantly faster for incoherent light than for coherent ultrafast excitation, for both continuum and bound wave packets. These results confirm that the dynamics observed in studies using ultrashort coherent pulses are not relevant to naturally occurring solar-induced processes such as photosynthesis and vision.

Alex C. Han; Moshe Shapiro; Paul Brumer

2012-11-25T23:59:59.000Z

391

Detection of Coherent Structures in Extreme-Scale Simulations  

Science Conference Proceedings (OSTI)

The analysis of coherent structures is a common problem in many scientific domains ranging from astrophysics to combustion, fusion, and materials science. The data from three-dimensional simulations are analyzed to detect the structures, extract statistics on them, and track them over time to gain insights into the phenomenon being modeled. This analysis is typically done off-line, using data that have been written out by the simulations. However, the move towards extreme scale architectures, with multi-core processors and graphical processing units, will affect how such analysis is done as it is unlikely that the systems will support the I/O bandwidth required for off-line analysis. Moving the analysis in-situ is a solution only if we know a priori what analysis will be done, as well as the algorithms used and their parameter settings. Even then, we need to ensure that this will not substantially increase the memory requirements or the data movement as the former will be limited and the latter will be expensive. In the Exa-DM project, a collaboration between Lawrence Livermore National Laboratory and University of Minnesota, we are exploring ways in which we can address the conflicting demands of coherent structure analysis of simulation data and the architecture of modern parallel systems, while enabling scientific discovery at the exascale. In this paper, we describe our work in two areas: the in situ implementation of an existing algorithm for coherent structure analysis and the use of graph-based techniques to efficiently compress the data.

Kamath, C; Iverson, J; Kirk, R; Karypis, G

2012-03-24T23:59:59.000Z

392

Optical coherence in astrophysics: The powerful alternative of big bang  

E-Print Network (OSTI)

The coherence of the interaction of light with a collisionless gas (Einstein 1917) founds the theory of gas lasers. It is, for the understanding of universe, a simpler and more powerful tool than the big bang which requires questionable supplements (dark matter, MOND, etc..). The Impulsive Stimulated Raman Scattering (ISRS) redshifts gradually light pulses which cross excited atomic hydrogen H*, so that the redshift is a measure of the column density of H*. Thus, the distance of the hot stars, surrounded by much H*, is exaggerated by the use of Hubble's law. Local exaggerated distances create voids in the maps of galaxies which become spongy. The interpretation of spectra of quasars, the periodicity of galaxy redshifts introduce an experimental "Karlsson's constant" exactly computed by ISRS. The need for dark matter comes from the exaggeration of the distance, therefore the size of galaxies. Without dark matter, celestial mechanics provides a reliable distance of spiral galaxies. Coherence also introduces superradiance and mode competition that explain that only the limbs of Str\\"omgren spheres are visible as circles maybe punctuated by an even number of dots: Too numerous, the figures assigned to gravitational lenses can be such limbs. The coincidence of the ignition of the rings of SNR1987A with the extinction of the star is due to a multiphoton coherent scattering of star light, which amplifies the superradiant emission of the rings.. A blueshift of microwaves crossing H* resulting, between 10 and 15 AU, of the expansion of solar wind, explains the "anomalous acceleration" of Pioneer probes. All is obtained without any change in theories of standard spectroscopy.

Jacques Moret-Bailly

2013-05-03T23:59:59.000Z

393

Coherent Radiation in Gamma-Ray Bursts and Relativistic Collisionless Shocks  

E-Print Network (OSTI)

We suggest that coherent radiation may occur in relativistic collisionless shocks via two-stream Weibel instabilities. The coherence amplifies the radiation power by many orders [$\\sim 10^{12}$ in Gamma-Ray Bursts (GRBs)] and particles cool very fast before being randomized. We imply (1) GRBs accompany strong infrared emission, (2) protons efficiently transfer energy to electrons and (3) prompt GRBs might be the upscattered coherent radiation.

Kunihito Ioka

2005-08-23T23:59:59.000Z

394

Quantum benchmark for storage and transmission of coherent states  

E-Print Network (OSTI)

We consider the storage and transmission of a Gaussian distributed set of coherent states of continuous variable systems. We prove a limit on the average fidelity achievable when the states are transmitted or stored by a classical channel, i.e., a measure and repreparation scheme which sends or stores classical information only. The obtained bound is tight and serves as a benchmark which has to be surpassed by quantum channels in order to outperform any classical strategy. The success in experimental demonstrations of quantum memories as well as quantum teleportation has to be judged on this footing.

K. Hammerer; M. M. Wolf; E. S. Polzik; J. I. Cirac

2004-09-17T23:59:59.000Z

395

Dynamic Pointer Allocation for Scalable Cache Coherence Directories  

E-Print Network (OSTI)

one of the primary challenges in building shared memory multiprocessors with hundreds or thousands of processors. While directory-based coherency schemes are promising because they rely on point-to-point messages rather than a network broadcast mechanism, traditional directory organizations would use a prohibitive amount of memory in a large-scale machine. In this paper we introduce a dynamic pointer allocation directory that exploits reference behavior characteristics of large-scale parallel programs to reduce directory storage requirements to manageable levels while maintaining performance comparable to traditional directory organizations.

Richard Simoni; Mark Horowitz

1991-01-01T23:59:59.000Z

396

Charge - dependent increase in coherence of synchrotron oscillation at injection  

SciTech Connect

Because of coupled bunch instability and/or because of some unidentified mechanism, bunches from the 8 GeV Booster accelerator at Fermilab arrive in the Main Injector synchrotron with a complicated centroid distribution in phase and energy. The currently installed broad band kicker provides a maximum of 2 kV, insufficient to remove injection errors before the oscillations would de-cohere, ignoring the influence of bunch charge. Perhaps surprisingly, for sufficient but generally modest charge, the effect of potential well distortion is to maintain bunch integrity. This talk illustrates the phenomenon for injection into the Fermilab Main Injector and offers an explanation sufficiently general to apply elsewhere.

MacLachlan, J.A.; /Fermilab

2004-11-01T23:59:59.000Z

397

Coherent Diffraction Radiation Longitudinal Beam Profile Monitor for CTF3  

E-Print Network (OSTI)

A setup for the investigation of Coherent Diffraction Radiation (CDR) from a conducting screen as a tool for noninvasive longitudinal electron beam profile diagnostics has been designed and installed in the Combiner Ring Measurement (CRM) line of the CLIC Test Facility (CTF3, CERN). In this report the status of the monitor development and results on the interferometric measurements of CDR spectra are presented. The CDR signal correlation with an RF pickup and a streak camera is reported. The future plans for the system improvements are also discussed

Micheler, Maximilian; Boorman, Gary; Karataev, Pavel; Lekomtsev, Konstantin; Molloy, Stephen; Corsini, Roberto; Dabrowski, Anne; Lefevre, Thibaut

2010-01-01T23:59:59.000Z

398

Aging in coherent noise models and natural time  

Science Conference Proceedings (OSTI)

Event correlation between aftershocks in the coherent noise model is studied by making use of natural time, which has recently been introduced in complex time-series analysis. It is found that the aging phenomenon and the associated scaling property discovered in the observed seismic data are well reproduced by the model. It is also found that the scaling function is given by the q-exponential function appearing in nonextensive statistical mechanics, showing power-law decay of event correlation in natural time.

Tirnakli, Ugur; Abe, Sumiyoshi [Department of Physics, Faculty of Science, Ege University, 35100 Izmir (Turkey); Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan)

2004-11-01T23:59:59.000Z

399

TESTS OF COHERENT QCD PHENOMENA AND NUCLEON SUBSTRUCTURE AT CEBAF  

E-Print Network (OSTI)

Measurements of exclusive processes such as electroproduction, photoproduction, and Compton scattering are among the most sensitive probes of proton structure and coherent phenomena in quantum chromodynamics. The continuous electron beam at CEBAF, upgraded in laboratory energy to 10–12 GeV, will allow a systematic study of exclusive, semi-inclusive, and inclusive reactions in a kinematic range well-tuned to the study of fundamental nucleon and nuclear substructure. I also discuss the potential at CEBAF for studying novel QCD phenomena at the charm production threshold, including the possible production of nuclear-bound quarkonium.

Stanley J. Brodsky; Cebaf Workshop On Electroproduction; Stanley J. Brodsky

1994-01-01T23:59:59.000Z

400

Coherent bremsstrahlung and GDR width from 252Cf cold fission  

E-Print Network (OSTI)

The energy spectrum of the high energy gamma-rays in coincidence with the prompt gamma rays has been measured for the spontaneous fission of 252Cf. The nucleus-nucleus coherent bremsstrahlung of the accelerating fission fragments is observed and the result has been substantiated with a theoretical calculation based on the coulomb acceleration model. The width of the giant dipole resonance (GDR) decay from the excited fission fragments has been extracted for the first time and compared with the thermal shape fluctuation model (TSFM) in the liquid drop formalism. The extracted GDR width is significantly smaller than the predictions of TSFM.

Deepak Pandit; S. Mukhopadhyay; Srijit Bhattacharya; Surajit Pal; A. De; S. R. Banerjee

2009-12-23T23:59:59.000Z

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.


401

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

402

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

403

Research Program towards Observation of Neutrino-Nucleus Coherent Scattering  

E-Print Network (OSTI)

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

Henry T. Wong

2005-11-01T23:59:59.000Z

404

Coherent electron cooling proof of principle instrumentation design  

SciTech Connect

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

405

Validation of a virtual source model for Monte Carlo dose calculations of a flattening filter free linac  

SciTech Connect

Purpose: A linac delivering intensity-modulated radiotherapy (IMRT) can benefit from a flattening filter free (FFF) design which offers higher dose rates and reduced accelerator head scatter than for conventional (flattened) delivery. This reduction in scatter simplifies beam modeling, and combining a Monte Carlo dose engine with a FFF accelerator could potentially increase dose calculation accuracy. The objective of this work was to model a FFF machine using an adapted version of a previously published virtual source model (VSM) for Monte Carlo calculations and to verify its accuracy. Methods: An Elekta Synergy linear accelerator operating at 6 MV has been modified to enable irradiation both with and without the flattening filter (FF). The VSM has been incorporated into a commercially available treatment planning system (Monaco Trade-Mark-Sign v 3.1) as VSM 1.6. Dosimetric data were measured to commission the treatment planning system (TPS) and the VSM adapted to account for the lack of angular differential absorption and general beam hardening. The model was then tested using standard water phantom measurements and also by creating IMRT plans for a range of clinical cases. Results: The results show that the VSM implementation handles the FFF beams very well, with an uncertainty between measurement and calculation of <1% which is comparable to conventional flattened beams. All IMRT beams passed standard quality assurance tests with >95% of all points passing gamma analysis ({gamma} < 1) using a 3%/3 mm tolerance. Conclusions: The virtual source model for flattened beams was successfully adapted to a flattening filter free beam production. Water phantom and patient specific QA measurements show excellent results, and comparisons of IMRT plans generated in conventional and FFF mode are underway to assess dosimetric uncertainties and possible improvements in dose calculation and delivery.

Cashmore, Jason; Golubev, Sergey; Dumont, Jose Luis; Sikora, Marcin; Alber, Markus; Ramtohul, Mark [Hall-Edwards Radiotherapy Research Group, University Hospital Birmingham NHS Foundation Trust, United Kingdom, B15 2TH (United Kingdom); Elekta CMS Software, St. Louis, Missouri 63043 (United States); Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen 5021 (Norway); Section for Biomedical Physics, University Hospital for Radiation Oncology, Hoppe-Seyler-Str 3, 72076, Tuebingen (Germany); Hall-Edwards Radiotherapy Research Group, University Hospital Birmingham NHS Foundation Trust, United Kingdom, B15 2TH (United Kingdom)

2012-06-15T23:59:59.000Z

406

A Very Intense Neutrino Super Beam Experiment for Leptonic CP Violation Discovery based on the European Spallation Source Linac: A Snowmass 2013 White Paper  

E-Print Network (OSTI)

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

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

2013-09-26T23:59:59.000Z

407

Symptoms and sense of coherence – a follow-up study of personnel ...  

Science Conference Proceedings (OSTI)

factors Æ Sense of coherence Æ Sick building syndrome. Introduction. There have been ... environment in the course of living are structured, predictable, and ...

408

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

409

Radiation from laser accelerated electron bunches: Coherent terahertz and femtosecond X-rays  

E-Print Network (OSTI)

of coherent transition radiation generated at a plasma-and G. Fubiani, “Terahertz radiation from laser acceleratedW. P. Leemans, “Synchrotron radiation from electron beams in

2004-01-01T23:59:59.000Z

410

On the optimality of Orthogonal Greedy Algorithm for M-coherent dictionaries  

E-Print Network (OSTI)

We show that Orthogonal Greedy Algorithms (Orthogonal Matching Pursuit) provides almost optimal approximation on the first [1/(20M)] steps for M-coherent dictionaries

Livshitz, Eugene

2010-01-01T23:59:59.000Z

411

Sliding coherence window technique for hierarchical detection of continuous gravitational waves  

E-Print Network (OSTI)

A novel hierarchical search technique is presented for all-sky surveys for continuous gravitational-wave sources, such as rapidly spinning nonaxisymmetric neutron stars. Analyzing yearlong detector data sets over realistic ranges of parameter space using fully coherent matched-filtering is computationally prohibitive. Thus more efficient, so-called hierarchical techniques are essential. Traditionally, the standard hierarchical approach consists of dividing the data into nonoverlapping segments of which each is coherently analyzed and subsequently the matched-filter outputs from all segments are combined incoherently. The present work proposes to break the data into subsegments shorter than the desired maximum coherence time span (size of the coherence window). Then matched-filter outputs from the different subsegments are efficiently combined by sliding the coherence window in time: Subsegments whose timestamps are closer than coherence window size are combined coherently, otherwise incoherently. Compared to the standard scheme at the same coherence time baseline, data sets longer by about 50-100% would have to be analyzed to achieve the same search sensitivity as with the sliding coherence window approach. Numerical simulations attest to the analytically estimated improvement.

Holger J. Pletsch

2011-01-27T23:59:59.000Z

412

Sliding coherence window technique for hierarchical detection of continuous gravitational waves  

Science Conference Proceedings (OSTI)

A novel hierarchical search technique is presented for all-sky surveys for continuous gravitational-wave sources, such as rapidly spinning nonaxisymmetric neutron stars. Analyzing yearlong detector data sets over realistic ranges of parameter space using fully coherent matched-filtering is computationally prohibitive. Thus more efficient, so-called hierarchical techniques are essential. Traditionally, the standard hierarchical approach consists of dividing the data into nonoverlapping segments of which each is coherently analyzed, and subsequently the matched-filter outputs from all segments are combined incoherently. The present work proposes to break the data into subsegments shorter than the desired maximum coherence time span (size of the coherence window). Then matched-filter outputs from the different subsegments are efficiently combined by sliding the coherence window in time: Subsegments whose timestamps are closer than coherence window size are combined coherently, otherwise incoherently. Compared to the standard scheme at the same coherence time baseline, data sets longer by about 50-100% would have to be analyzed to achieve the same search sensitivity as with the sliding coherence window approach. Numerical simulations attest to the analytically estimated improvement.

Pletsch, Holger J. [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Leibniz Universitaet Hannover, Callinstrasse 38, D-30167 Hannover (Germany)

2011-06-15T23:59:59.000Z

413

Design of an RFQ-based, H/sup -/ injector for the BNL/FNAL 200 MeV proton linacs  

SciTech Connect

An LBL/BNL/FNAL collaboration has been formed to design an RFQ-based Cockcroft-Walton replacement, suitable for use at the Brookhaven and Fermilab 200 MeV proton linacs. A common design for the ion source and the RFQ will result in an economical construction and testing program compatible with both applications. The technical requirements have been evaluated and it appears that they can be satisfied with identical RFQs, capable of accelerating 50 mA of H/sup -/ from 35 to 750 keV, at a nominal frequency of 200 MHz.

Gough, R.A.; Staples, J.; Tanabe, J.; Yee, D.; Howard, D.; Curtis, C.; Prelec, K.

1986-06-01T23:59:59.000Z

414

Effects of e-beam parameters on coherent electron cooling  

Science Conference Proceedings (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

415

Atomic Resolution Coherent Diffractive Imaging and Ultrafast Science  

Science Conference Proceedings (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

2011-01-12T23:59:59.000Z

416

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

SciTech Connect

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

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

2012-07-03T23:59:59.000Z

417

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

Science Conference Proceedings (OSTI)

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

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

2010-05-12T23:59:59.000Z

418

Low-coherence enhanced backscattering of light: characteristics and applications for colon cancer screening  

E-Print Network (OSTI)

-cooled atoms,5 liquid crystals,6 photonic crystals,7 amplifying materials,8, 9 and solar system bodies.10 system, we varied the spatial coherence length Lsc of the incident light from 200 µm to 35 µmLow-coherence enhanced backscattering of light: characteristics and applications for colon cancer

Pradhan, Prabhakar

419

NOTES AND CORRESPONDENCE Spatial coherence of monsoon onset over Western and Central Sahel (19502000)  

E-Print Network (OSTI)

NOTES AND CORRESPONDENCE Spatial coherence of monsoon onset over Western and Central Sahel.marteau@ubourgogne.fr Abstract: The spatial coherence of boreal monsoon onset over Western and Central Sahel (Senegal, Mali of the whole monsoon system. Previous work has shown that the northward shift, which determines

Paris-Sud XI, Université de

420

Searchback Algorithms for TOA Estimation in Non-coherent Low-rate IR-UWB Systems  

Science Conference Proceedings (OSTI)

Non-coherent ultra-wideband (UWB) receivers offer an attractive low-complexity solution to ranging with UWB radios. They use a simple receiver architecture that can operate at very low sampling rates compared to the Nyquist rate. In this paper, time-of-arrival ... Keywords: Energy detector, First path detection, Non-coherent, Ranging, Sub-Nyquist sampling, UWB

I. Guvenc; Z. Sahinoglu; P. Orlik; H. Arslan

2009-03-01T23:59:59.000Z

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.


421

LETTER Communicated by Emilio Salinas Assessing Neuronal Coherence with Single-Unit, Multi-Unit,  

E-Print Network (OSTI)

LETTER Communicated by Emilio Salinas Assessing Neuronal Coherence with Single-Unit, Multi-Unit the correlated input and multi-unit activity increases proportionally with the square root of the number of neurons in the multi-unit recording. The coherence between two typical multi-unit recordings (2 to 10

Gielen, C.C.A.M.

422

Photon Sciences | Beamlines | CSX: Coherent Soft X-ray Scattering and  

NLE Websites -- All DOE Office Websites (Extended Search)

CSX: Coherent Soft X-ray Scattering and polarization CSX: Coherent Soft X-ray Scattering and polarization X-Ray 1 Poster | X-Ray 2 Poster | Fact Sheet | Preliminary Design Report Scientific Scope The Coherent Soft X-ray Scattering and Polarization (CSX) beamline design (source and optics) has been optimized to the NSLS-II parameters to provide the highest possible flux for experiments requiring either high coherence or full control of the polarization. Beamline Description The CSX beamline will be served by two identical EPU49 sources. Both EPUs are planned to operate in a canted geometry with opposite circular polarization for fast polarization switching experiments at the full polarization control (PC) branch. The EPUs will also be able to operate "phased" as a single device for high coherent flux experiments at the

423

Part 2: Coherent emission from Free Electron Lasers  

NLE Websites -- All DOE Office Websites (Extended Search)

0 0 Electron beam-based sources of ultrashort x-ray pulses Alexander Zholents Advanced Photon Source, Argonne National Laborator , Argonne, IL 60439 (September 7, 2010) To be published by World Scientific Publishing Co. in Reviews of Accelerator Science and Technology. y 2 Electron beam-based sources of ultrashort x-ray pulses * Alexander Zholents Argonne National Laboratory, Advanced Photon Source, 9700 South Cass Ave., Argonne, IL 60439 Abstract A review of various methods for generation of ultrashort x-ray pulses using relativistic electron beam from conventional accelerators is presented. Both spontaneous and coherent emission of electrons is considered. Introduction The importance of the time-resolved studies of matter at picosecond (ps),

424

Rf system for the NSLS coherent infrared radiation source  

Science Conference Proceedings (OSTI)

The existing NSLS X-ray Lithography Source (XLS Phase I) is being considered for a coherent synchrotron radiation source. The existing 211 MHz warm cavity will be replaced with a 5-cell 2856 MHz superconducting RF cavity, driven by a series of 2 kW klystrons. The RF system will provide a total V{sub RF} of 1.5 MV to produce {sigma}{sub L} = 0.3 mm electron bunches at an energy of 150 MeV. Superconducting technology significantly reduces the required space and power needed to achieve the higher voltage. It is the purpose of this paper to describe the superconducting RF system and cavity, power requirements, and cavity design parameters such as input coupling, Quality Factor, and Higher Order Modes.

Broome, W.; Biscardi, R.; Keane, J.; Mortazavi, P.; Thomas, M.; Wang, J.M.

1995-05-01T23:59:59.000Z

425

Coherent scattering by a spherical medium of resonant atoms  

Science Conference Proceedings (OSTI)

We consider the problem of coherent resonant scattering of electromagnetic waves by a spherical medium of two-level atoms. The frequency dependence of the scattering amplitudes and cross sections reveals a complex structure of narrow peaks and dips. We relate these scattering resonances to the cooperative emission resonances characteristic of a sphere. We find the scattering to show considerable interference between the electric and magnetic multipole contributions, particularly in the lower multipole orders. This interference tends to enhance anisotropies in the differential scattering cross section even for small spheres. For such spheres, the peak values of the resonant contributions of the low-order multipoles to the total scattering cross section can increase with multipole order, in contrast to the usual decrease seen in nonresonant scattering.

Prasad, Sudhakar; Glauber, Roy J. [Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Lyman Laboratory of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

2011-06-15T23:59:59.000Z

426

Ultrafast laser based coherent control methods for explosives detection  

SciTech Connect

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

427

Influence of electron beam parameters on coherent electron cooling  

Science Conference Proceedings (OSTI)

Coherent electron cooling (CeC) promises to revolutionize the cooling of high energy hadron beams. The intricate dynamics of the CeC depends both on the local density and energy distribution of the beam. The variations of the local density (beam current) are inevitable in any realistic beam. Hence, in this paper we propose a novel method of beam conditioning. The conditioning provides compensation of effect from such variation by a correlated energy modulation. We use our analytical FEL model for an electron bunch with Gaussian line charge density and cosine-type energy variation along bunch. We analyze the phase variation between the electron density modulation at the exit of the FEL-amplifier and the ions inducing it in the modulator as a function of the peak current and the electron beam energy. Based on this analysis, electron bunch parameters for optimal CeC cooling are found numerically.

Wang G.; Hao, Y.; Litvinenko, V.N.; Webb, S.

2012-05-20T23:59:59.000Z

428

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.

Volkovich, Roie

2010-01-01T23:59:59.000Z

429

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

430

Lagrangian Coherent Structure Analysis of Terminal Winds Detected by Lidar. Part II: Structure Evolution and Comparison with Flight Data  

Science Conference Proceedings (OSTI)

Using observational data from coherent Doppler light detection and ranging (lidar) systems situated at the Hong Kong International Airport (HKIA), the authors extract Lagrangian coherent structures (LCS) intersecting the flight path of landing ...

Wenbo Tang; Pak Wai Chan; George Haller

2011-10-01T23:59:59.000Z

431

First Measurements of the Longitudinal Bunch Profile at SLAC Using Coherent Smith-Purcell Radiation at 28GeV  

E-Print Network (OSTI)

First Measurements of the Longitudinal Bunch Profile at SLAC Using Coherent Smith-Purcell Radiation at 28GeV

Blackmore, V; Doucas, G; Kimmitt, M F; Molloy, S; Ottewell, B; Perry, C; Woods, M

2008-01-01T23:59:59.000Z

432

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 are not known. These limitations become extremely important when interpreting coherency within poorly acquired or processed data sets. In order to obtain a better understanding of the coherency limitations, various synthetic seismic data sets were created. The sensitivity of the coherency algorithms to variations in wave frequency, signal-to-noise ratio and fault throw was investigated. Correlation between the coherency values of a faulted reflector and the known offset shows that coherency has the ability to detect the presence of various scale features that may be previously thought to be below seismic resolution or difficult to discriminate with conventional interpretation methods. Coherency values had a smaller standard deviation and were less sensitive to noise when processed with a temporal window length less than one period. A fault could be detected by coherency when the signal-to-noise ratio was >3. A fault could also be detected as long as the throw-to-wavelength ratio was >5% or two-way traveltime-toperiod >10%. Therefore, this study suggests that coherency has the ability to detect a fault as long as the frequency of the data imaging that fault has a period no greater than one order of magnitude to the traveltime through the fault and that the signal can easily be distinguished from noise. Results from application of the coherency analysis were applied to the characterization of a very deep fault and fracture system imaged by a field seismic data set. A series of reverse and strike-slip faults were detected and mapped. Magnitudes of the throws for these faults were not known, but subtle amplitude anomalies in seismic sections confirmed the coherency analysis. The results of this study suggest that coherency has demonstrated an ability to detect features that would normally beoverlooked using traditional interpretation methods and has many future implications for poorly imaged seismic areas, such as sub-salt.

Barnett, David Benjamin

2003-05-01T23:59:59.000Z

433

Direct Coherency Identification of Synchronous Generators in Taiwan Power System Based on Fuzzy c-Means Clustering  

Science Conference Proceedings (OSTI)

This paper is to investigate the application of fuzzy c-means clustering to the direct identification of coherent synchronous generators in power systems. Because of the conceptual appropriateness and computational simplicity, this approach is essentially ... Keywords: cluster analysis, coherency identification, coherency measure, fuzzy c-means, power system dynamic equivalent

Shu-Chen Wang; Pei-Hwa Huang; Chi-Jui Wu; Yung-Sung Chuang

2007-10-01T23:59:59.000Z

434

Induction Linac Pulsers  

E-Print Network (OSTI)

or a lumped element transmission line. The typical switcha tapered impedance transmission line. The ERA pulse lineand a tapered radial transmission line. Because of the

Faltens, Andris

2011-01-01T23:59:59.000Z

435

Pulse power linac  

DOE Patents (OSTI)

A linear acceleration for charged particles is constructed of a plurality of transmission line sections that extend between a power injection region and an accelerating region. Each line section is constructed of spaced plate-like conductors and is coupled to an accelerating gap located at the accelerating region. Each gap is formed between a pair of apertured electrodes, with all of the electrode apertures being aligned along a particle accelerating path. The accelerating gaps are arranged in series, and at the injection region the line sections are connected in parallel. At the injection region a power pulse is applied simultaneously to all line sections. The line sections are graduated in length so that the pulse reaches the gaps in a coordinated sequence whereby pulse energy is applied to particles as they reach each of the gaps along the accelerating path.

Villa, Francesco (Alameda, CA)

1990-01-01T23:59:59.000Z

436

REVIEW OF INDUCTION LINACS  

E-Print Network (OSTI)

magnetic cores, and transmission line effects in dielectricof the core. The transmission line in Fig. 3 either transit-considering the bent transmission line model of Fig. 3, with

Faltens, A.

2010-01-01T23:59:59.000Z

437

Alternating phase focused linacs  

SciTech Connect

A heavy particle linear accelerator employing rf fields for transverse and ongitudinal focusing as well as acceleration. Drift tube length and gap positions in a standing wave drift tube loaded structure are arranged so that particles are subject to acceleration and succession of focusing and defocusing forces which contain the beam without additional magnetic or electric focusing fields.

Swenson, Donald A. (Los Alamos, NM)

1980-01-01T23:59:59.000Z

438

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

439

Reversible Seeding in Storage Rings  

Science Conference Proceedings (OSTI)

We propose to generate steady-state microbunching in a storage ring with a reversible seeding scheme. High gain harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG) are two promising methods for microbunching linac electron beams. Because both schemes increase the energy spread of the seeded beam, they cannot drive a coherent radiator turn-by-turn in a storage ring. However, reversing the seeding process following the radiator minimizes the impact on the electron beam and may allow coherent radiation at or near the storage ring repetition rate. In this paper we describe the general idea and outline a proof-of-principle experiment. Electron storage rings can drive high average power light sources, and free-electron lasers (FELs) are now producing coherent light sources of unprecedented peak brightness While there is active research towards high repetition rate FELs (for example, using energy recovery linacs), at present there are still no convenient accelerator-based sources of high repetition rate, coherent radiation. As an alternative avenue, we recently proposed to establish steady-state microbunching (SSMB) in a storage ring. By maintaining steady-state coherent microbunching at one point in the storage ring, the beam generates coherent radiation at or close to the repetition rate of the storage ring. In this paper, we propose a method of generating a microbunched beam in a storage ring by using reversible versions of linac seeding schemes.

Ratner, Daniel; Chao, Alex; /SLAC

2011-12-14T23:59:59.000Z

440

Rydberg atom detection of the temporal coherence of cosmic microwave background radiation  

E-Print Network (OSTI)

Rydberg atoms immersed in cold blackbody radiation are shown to display long-lived quantum coherence effects on timescales of tens of picoseconds. By solving non-Markovian equations of motion with no free parameters we obtain the time evolution of the density matrix, and demonstrate that the blackbody-induced temporal coherences manifest as quantum beats in time-resolved fluorescence intensities of the Rydberg atoms. A measurable fluorescence signal can be obtained with a cold trapped ensemble of 1e8 Rydberg atoms subject to 2.7 K cosmic microwave background radiation (CMB), allowing for novel insights into previously unexamined quantum coherence properties of CMB.

Tscherbul, Timur V

2013-01-01T23:59:59.000Z

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.


441

Rydberg atom detection of the temporal coherence of cosmic microwave background radiation  

E-Print Network (OSTI)

Rydberg atoms immersed in cold blackbody radiation are shown to display long-lived quantum coherence effects on timescales of tens of picoseconds. By solving non-Markovian equations of motion with no free parameters we obtain the time evolution of the density matrix, and demonstrate that the blackbody-induced temporal coherences manifest as decaying quantum beats in time-resolved fluorescence intensities of the Rydberg atoms. A measurable fluorescence signal can be obtained with a cold trapped ensemble of 10^8 Rydberg atoms subject to suitably amplified cosmic microwave background radiation (CMB) at 2.7 K, allowing for novel insights into previously unexamined quantum coherence properties of CMB.

Timur V. Tscherbul; Paul Brumer

2013-05-23T23:59:59.000Z

442

Coherent beam-beam effects observation and mitigation at the RHIC collider  

SciTech Connect

In polarized proton operation in RHIC coherent beam-beam modes are routinely observed with beam transfer function measurements in the vertical plane. With the existence of coherent modes a larger space is required in the tune diagram than without them and stable conditions can be compromised for operation with high intensity beams as foreseen for future luminosity upgrades. We report on experiments and simulations carried out to understand the existence of coherent modes in the vertical plane and their absence in the horizontal plane, and investigate possible mitigation strategies.

White S.; Fischer, W.; Luo, Y.

2012-05-20T23:59:59.000Z

443

Swift Loss of Coherence of Soliton Trains in Attractive Bose-Einstein Condensates  

SciTech Connect

Experiments on ultracold attractive Bose-Einstein condensates (BECs) have demonstrated that at low dimensions atomic clouds can form localized objects, propagating for long times without significant changes in their shapes and attributed to bright matter-wave solitons, which are coherent objects. We consider the dynamics of bright soliton trains from the perspective of many-boson physics. The fate of matter-wave soliton trains is actually to quickly lose their coherence and become macroscopically fragmented BECs. The death of the coherent matter-wave soliton trains gives birth to fragmented objects, whose quantum properties and experimental signatures differ substantially from what is currently assumed.

Streltsov, Alexej I.; Cederbaum, Lorenz S. [Theoretische Chemie, Physikalisch-Chemisches Institut, Universitaet Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany); Alon, Ofir E. [Theoretische Chemie, Physikalisch-Chemisches Institut, Universitaet Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany); Department of Physics, University of Haifa at Oranim, Tivon 36006 (Israel)

2011-06-17T23:59:59.000Z

444

Radiative Reactions and Coherence Modeling in the High Altitude Electromagnetic Pulse  

E-Print Network (OSTI)

A high altitude nuclear electromagnetic pulse (EMP) with a peak field intensity of 5 x 10^4 V/m carries momentum that results in a retarding force on the average Compton electron (radiating coherently to produce the waveform) with magnitude near that of the geomagnetic force responsible for the coherent radiation. The retarding force results from a self field effect. The Compton electron interaction with the self generated magnetic field due to the other electrons accounts for the momentum density in the propagating wave; interaction with the self generated electric field accounts for the energy flux density in the propagating wave. Coherent addition of radiation is also quantitatively modeled.

Charles N. Vittitoe; Mario Rabinowitz

2003-06-03T23:59:59.000Z

445

Small Particles, Big Impact  

NLE Websites -- All DOE Office Websites (Extended Search)

Small Particles, Big Impact Small Particles, Big Impact Small-scale effects of Aerosols Add up Over Time August 24, 2011 | Tags: Climate Research, Earth Sciences, Environmental...

446

Quantum key distribution using gaussian-modulated coherent states  

E-Print Network (OSTI)

Quantum continuous variables are being explored as an alternative means to implement quantum key distribution, which is usually based on single photon counting. The former approach is potentially advantageous because it should enable higher key distribution rates. Here we propose and experimentally demonstrate a quantum key distribution protocol based on the transmission of gaussian-modulated coherent states (consisting of laser pulses containing a few hundred photons) and shot-noise-limited homodyne detection; squeezed or entangled beams are not required. Complete secret key extraction is achieved using a reverse reconciliation technique followed by privacy amplification. The reverse reconciliation technique is in principle secure for any value of the line transmission, against gaussian individual attacks based on entanglement and quantum memories. Our table-top experiment yields a net key transmission rate of about 1.7 megabits per second for a loss-free line, and 75 kilobits per second for a line with losses of 3.1 dB. We anticipate that the scheme should remain effective for lines with higher losses, particularly because the present limitations are essentially technical, so that significant margin for improvement is available on both the hardware and software.

F. Grosshans; G. Van Assche; J. Wenger; R. Brouri; N. J. Cerf; Ph. Grangier

2003-12-02T23:59:59.000Z

447

Coherent detection method of gravitational wave bursts for spherical antennas  

E-Print Network (OSTI)

We provide a comprehensive theoretical framework and a quantitative test of the method we recently proposed for processing data from a spherical detector with five or six transducers. Our algorithm is a trigger event generator performing a coherent analysis of the sphere channels. In order to test our pipeline we first built a detailed numerical model of the detector, including deviations from the ideal case such as quadrupole modes splitting, and non-identical transducer readout chains. This model, coupled with a Gaussian noise generator, has then been used to produce six time series, corresponding to the outputs of the six transducers attached to the sphere. We finally injected gravitational wave burst signals into the data stream, as well as bursts of non-gravitational origin in order to mimic the presence of non-Gaussian noise, and then processed the mock data. We report quantitative results for the detection efficiency versus false alarm rate and for the affordability of the reconstruction of the direction of arrival. In particular, the combination of the two direction reconstruction methods can reduce by a factor of 10 the number false alarms due to the non-Gaussian noise.

S. Foffa; R. Sturani

2008-12-22T23:59:59.000Z

448

Quantum-Bayesian Coherence: The No-Nonsense Version  

E-Print Network (OSTI)

In the Quantum-Bayesian interpretation of quantum theory (or QBism), the Born Rule cannot be interpreted as a rule for setting measurement-outcome probabilities from an objective quantum state. But if not, what is the role of the rule? In this paper, we argue that it should be seen as an empirical addition to Bayesian reasoning itself. Particularly, we show how to view the Born Rule as a normative rule in addition to usual Dutch-book coherence. It is a rule that takes into account how one should assign probabilities to the consequences of various intended measurements on a physical system, but explicitly in terms of prior probabilities for and conditional probabilities consequent upon the imagined outcomes of a special counterfactual reference measurement. This interpretation is seen particularly clearly by representing quantum states in terms of probabilities for the outcomes of a fixed, fiducial symmetric informationally complete (SIC) measurement. We further explore the extent to which the general form of the new normative rule implies the full state-space structure of quantum mechanics.

Christopher A. Fuchs; Ruediger Schack

2013-01-15T23:59:59.000Z

449

Micro loop heat pipe evaporator coherent pore structures  

E-Print Network (OSTI)

Loop heat pipes seem a promising approach for application in modern technologies where such thermal devices as cooling fans and radiators cannot satisfy overall requirements. Even though a loop heat pipe has a big potential to remove the thermal energy from a high heat flux source, the heat removal performance of heat pipes cannot be predicted well since a first principles of evaporation has not been established. An evaporation model based on statistical rate theory has been recently suggested by Ward and developed for a single pore by Oinuma. A loop heat pipe with coherent pore wick structure has been proposed as a design model. To limit product development risk and to enhance performance assurance, design model features and performance parameters have been carefully reviewed during the concept development phase and have been deliberately selected so as to be well-founded on the limited existing loop heat pipe knowledge base. A first principles evaporation model has been applied for evaporator geometry optimization. A number of iteration calculations have been performed to satisfy design and operating limitations. A set of recommendations for design optimization has been formulated. An optimal model has been found and proposed for manufacture and experimental investigation.

Alexseev, Alexandre Viktorovich

2003-08-01T23:59:59.000Z

450

Conditional Sampling of Coherent Structures in Atmospheric Turbulence Using the Wavelet Transform  

Science Conference Proceedings (OSTI)

The development and evaluation of a technique to detect and retrieve coherent structures embedded in a record of atmospheric surface-layer temperature fluctuations is described. This new detection scheme, based on a local wavelet transform, is ...

B. J. Turner; M. Y. Leclerc

1994-02-01T23:59:59.000Z

451

Advances in Optical Coherence Tomography and Microscopy for endoscopic applications and functional neuroimaging  

E-Print Network (OSTI)

Optical Coherence Tomography (OCT) is a developing medical imaging technology that generates micron resolution cross-sectional images of subsurface internal tissue structure in situ and in real time, without the need to ...

Aguirre, Aaron Dominic, 1977-

2008-01-01T23:59:59.000Z

452

High speed optical coherence microscopy with autofocus adjustment and a miniaturized endoscopic imaging probe  

E-Print Network (OSTI)

Optical coherence microscopy (OCM) is a promising technique for high resolution cellular imaging in human tissues. An OCM system for high-speed en face cellular resolution imaging was developed at 1060 nm wavelength at ...

Aguirre, Aaron Dominic

453

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

454

Exact dynamics for optical coherent-state qubits subject to environment noise  

E-Print Network (OSTI)

We study the exact dynamics of optical qubits encoded via coherent states with opposite phases which are interacting with an environment modeled as a collection of simple harmonic oscillators. Making use of a coherent-state path integral formulation, we are able to study memory effects on the dynamics of the coherent-state qubits due to strong environment coupling. We apply this formulation to examine the time evolution of a noisy quantum channel formed by two coherent-state qubits that are subject to uncorrelated local environment noises. In particular, we examine the time evolution of entanglement and maximal teleportation fidelity of the noisy quantum channel and show that at strong coupling, due to large feedback effects from the environment noise, it is possible to maintain a robust quantum channel in the long-time limit if appropriate error-correcting code is applied.

Ming-Jay Yang; Shin-Tza Wu

2013-10-04T23:59:59.000Z

455

Longshore Coherence of Currents on the Southern California Shelf During the Summer  

Science Conference Proceedings (OSTI)

Observations of horizontal currents and temperature made along a mid-shelf isobath during the summer on the Southern California shelf are used to determine longshore coherent length scales. The observations are characterized by weak atmospheric ...

C. D. Winant

1983-01-01T23:59:59.000Z

456

Measurement of Atmospheric Aspect Sensitivity Using Coherent Radar Imaging after Mitigation of Radar Beam Weighting Effect  

Science Conference Proceedings (OSTI)

The aspect angle, a measurement of the aspect sensitivity of atmospheric refractivity irregularities, was estimated with multiple-receiver coherent radar imaging (CRI) of very high frequency (VHF) atmospheric radar. Two CRI parameters retrieved by ...

Jenn-Shyong Chen; Jun-ichi Furumoto

2013-02-01T23:59:59.000Z

457

High Resolution Measurements of Turbulence, Velocity and Stress Using a Pulse-to-Pulse Coherent Sonar  

Science Conference Proceedings (OSTI)

Considered are the capabilities of a recently developed pulse-to-pulse coherent sonar called the High Resolution Current Profiler (HRCP). Special emphasis is placed on methods whereby reliable and accurate vertical profiles of turbulence ...

Atle Lohrmann; Bruce Hackett; Lars Petter Røed

1990-02-01T23:59:59.000Z

458

Lagrangian Coherent Structure Analysis of Terminal Winds Detected by Lidar. Part I: Turbulence Structures  

Science Conference Proceedings (OSTI)

The accurate real-time detection of turbulent airflow patterns near airports is important for safety and comfort in commercial aviation. In this paper, a method is developed to identify Lagrangian coherent structures (LCS) from horizontal lidar ...

Wenbo Tang; Pak Wai Chan; George Haller

2011-02-01T23:59:59.000Z

459

Coherency Strain and the Kinetics of Phase Separation in LiFePO [subscript 4  

E-Print Network (OSTI)

A theoretical investigation of the effects of elastic coherency strain on the thermodynamics, kinetics, and morphology of intercalation in single LiFePO4 nanoparticles yields new insights into this important battery material. ...

Cogswell, Daniel A.

460

Seasonal Predictability and Spatial Coherence of Rainfall Characteristics in the Tropical Setting of Senegal  

Science Conference Proceedings (OSTI)

This study examines space–time characteristics of seasonal rainfall predictability in a tropical region by analyzing observed data and model simulations over Senegal. Predictability is analyzed in terms of the spatial coherence of observed ...

Vincent Moron; Andrew W. Robertson; M. Neil Ward

2006-11-01T23:59:59.000Z

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.


461

Simulation of Coherent Doppler Lidar Performance for Space-Based Platforms  

Science Conference Proceedings (OSTI)

The performance of coherent Doppler lidar velocity estimates for a space-based platform are produced using computer simulations of raw data and statistical descriptions of the resulting velocity estimates. The random spatial variability of the ...

Rod Frehlich

2000-02-01T23:59:59.000Z

462

Statistical Reliability of Neighboring Range Bin Estimates of Coherent Fractional Contributions to Radar Backscattered Power  

Science Conference Proceedings (OSTI)

It was recently demonstrated that magnitudes of the power-normalized cross-correlation functions of complex amplitudes in neighboring range bins are identical to the fractional contributions made by radar coherent backscatter in the direction of ...

A. R. Jameson

2011-03-01T23:59:59.000Z

463

Long-lived quantum coherence in photosynthetic complexes at physiological temperature  

E-Print Network (OSTI)

Photosynthetic antenna complexes capture and concentrate solar radiation by transferring the excitation to the reaction center which stores energy from the photon in chemical bonds. This process occurs with near-perfect quantum efficiency. Recent experiments at cryogenic temperatures have revealed that coherent energy transfer - a wavelike transfer mechanism - occurs in many photosynthetic pigment-protein complexes (1-4). Using the Fenna-Matthews-Olson antenna complex (FMO) as a model system, theoretical studies incorporating both incoherent and coherent transfer as well as thermal dephasing predict that environmentally assisted quantum transfer efficiency peaks near physiological temperature; these studies further show that this process is equivalent to a quantum random walk algorithm (5-8). This theory requires long-lived quantum coherence at room temperature, which never has been observed in FMO. Here we present the first evidence that quantum coherence survives in FMO at physiological temperature for at l...

Panitchayangkoon, Gitt; Fransted, Kelly A; Caram, Justin R; Harel, Elad; Wen, Jianzhong; Blankenship, Robert E; Engel, Gregory S

2010-01-01T23:59:59.000Z

464

Simulations of partially coherent focal plane imaging arrays: Fisher matrix approach to performance evaluation  

E-Print Network (OSTI)

Focal plane arrays of bolometers are increasingly employed in astronomy at far--infrared to millimetre wavelengths. The focal plane fields and the detectors are both partially coherent in these systems, but no account has previously been taken of the effect of partial coherence on array performance. In this paper, we use our recently developed coupled--mode theory of detection together with Fisher information matrix techniques from signal processing to characterize the behaviour of partially coherent imaging arrays. We investigate the effects of the size and coherence length of both the source and the detectors, and the packing density of the array, on the amount of information that can be extracted from observations with such arrays.

George Saklatvala; Michael P. Hobson; Stafford Withington

2007-03-07T23:59:59.000Z

465

Spatial Coherence of Monsoon Onset over Western and Central Sahel (1950–2000)  

Science Conference Proceedings (OSTI)

The spatial coherence of boreal monsoon onset over the western and central Sahel (Senegal, Mali, Burkina Faso) is studied through the analysis of daily rainfall data for 103 stations from 1950 to 2000. Onset date is defined using a local ...

Romain Marteau; Vincent Moron; Nathalie Philippon

2009-03-01T23:59:59.000Z

466

Simulation of Coherent Doppler Lidar Performance in the Weak-Signal Regime  

Science Conference Proceedings (OSTI)

The performance of coherent Doppler lidar in the weak-signal regime is investigated by computer simulations of velocity estimators that accumulate the signal from N pulses of zero-mean complex Gaussian stationary lidar data described by a ...

Rod Frehlich

1996-06-01T23:59:59.000Z

467

Coherent control of hyperfine-coupled electron and nuclear spins for quantum information processing  

E-Print Network (OSTI)

Coupled electron-nuclear spins are promising physical systems for quantum information processing: By combining the long coherence times of the nuclear spins with the ability to initialize, control, and measure the electron ...

Yang, Jamie Chiaming

2008-01-01T23:59:59.000Z

468

A C-Band Coherent Polarimetric Radar for Propagation and Cloud Physics Research  

Science Conference Proceedings (OSTI)

At DFVLR in Oberpfaffenhofen, West Germany, a recently developed coherent polarimetric C-band radar is now in operation for research in atmospheric physics and radio wave propagation physics. Its capabilities provide opportunities to investigate ...

Arno C. Schroth; Madhukar S. Chandra; Peter F. Mesichner

1988-12-01T23:59:59.000Z

469

Coherent transport on Apollonian networks and continuous-time quantum walks  

E-Print Network (OSTI)

We study the coherent exciton transport on Apollonian networks generated by simple iterative rules. The coherent exciton dynamics is modeled by continuous-time quantum walks and we calculate the transition probabilities between two nodes of the networks. We find that the transport depends on the initial nodes of the excitation. For networks less than the second generation the coherent transport shows perfect revivals when the initial excitation starts at the central node. For networks of higher generation, the transport only shows partial revivals. Moreover, we find that the excitation is most likely to be found at the initial nodes while the coherent transport to other nodes has a very low probability. In the long time limit, the transition probabilities show characteristic patterns with identical values of limiting probabilities. Finally, the dynamics of quantum transport are compared with the classical transport modeled by continuous-time random walks.

Xinping Xu; Wei Li; Feng Liu

2008-10-06T23:59:59.000Z

470

Noise figure and photon probability distribution in Coherent Anti-Stokes Raman Scattering (CARS)  

E-Print Network (OSTI)

The noise figure and photon probability distribution are calculated for coherent anti-Stokes Raman scattering (CARS) where an anti-Stokes signal is converted to Stokes. We find that the minimum noise figure is ~ 3dB.

Dimitropoulos, D; Jalali, B; Solli, D R

2006-01-01T23:59:59.000Z

471

Pulse-to-Pulse Coherent Doppler Measurements of Waves and Turbulence  

Science Conference Proceedings (OSTI)

This paper presents laboratory and field testing of a pulse-to-pulse coherent acoustic Doppler profiler for the measurement of turbulence in the ocean. In the laboratory, velocities and wavenumber spectra collected from Doppler and digital ...

Fabrice Veron; W. Kendall Melville

1999-11-01T23:59:59.000Z

472

The Pulsed Coherent Doppler Lidar: Observations of Frontal Structure and the Planetary Boundary Layer  

Science Conference Proceedings (OSTI)

The NOAA/WPL pulsed coherent Doppler lidar was used during the Texas Frontal Experiment in 1985 to study mesoscale preconvective atmospheric conditions. On 22 April 1985, the Doppler lidar, in conjunction with serial rawinsonde ascents and ...

Paul J. Neiman; M. A. Shapiro; R. Michael Hardesty; B. Boba Stankov; Rhidian T. Lawrence; Robert J. Zamora; Tamara Hampel

1988-08-01T23:59:59.000Z

473

Lattice Studies for CIRCE (Coherent InfraRed CEnter) at the ALS  

E-Print Network (OSTI)

Lattice Studies for CIRCE (Coherent InfraRed CEnter) at theis neces- sary. The lattice for CIRCE allows controllingThe paper describes the lattice and presents the calculated

Nishimura, Hiroshi; Robin, David; Sannibale, Fernando; Wan, Weishi

2004-01-01T23:59:59.000Z

474

Coherent Scattering of Microwaves by Particles: Evidence from Clouds and Smoke  

Science Conference Proceedings (OSTI)

Many radar measurements of the atmosphere can be explained in terms of two scattering mechanisms: incoherent scattering from particles, and coherent scattering from variations in the refractive index of the air, commonly called clear-air or Bragg ...

J. S. Erkelens; V. K. C. Venema; H. W. J. Russchenberg; L. P. Ligthart

2001-05-01T23:59:59.000Z

475

Real-Time Monitoring and Prediction of Modes of Coherent Synoptic to Intraseasonal Tropical Variability  

Science Conference Proceedings (OSTI)

A technique of near-real-time monitoring and prediction of various modes of coherent synoptic to intraseasonal zonally propagating tropical variability is developed. It involves Fourier filtering of a daily updated global dataset for the specific ...

Matthew Wheeler; Klaus M. Weickmann

2001-11-01T23:59:59.000Z

476

IKNO, a user facility for coherent terahertz and UV synchrotron radiation  

E-Print Network (OSTI)

IKNO is a real multi-user facility that accommodates a largeIKNO, a user facility for coherent terahertz and UVis a proposal for a multi-user facility based on an electron

Sannibale, Fernando

2009-01-01T23:59:59.000Z

477

Wavelet Analysis of Coherent Structures at the Atmosphere-Forest Interface  

Science Conference Proceedings (OSTI)

Wavelet analysis was applied to turbulence data for temperature and vertical velocity within and above a deciduous forest. This method appears to provide an objective technique for examining thermal and flow fields associated with coherent ...

W. Gao; B. L. Li

1993-11-01T23:59:59.000Z

478

Clustered Geometries Exploiting Quantum Coherence Effects for Efficient Energy Transfer in Light Harvesting  

E-Print Network (OSTI)

Elucidating quantum coherence effects and geometrical factors for efficient energy transfer in photosynthesis has the potential to uncover non-classical design principles for advanced organic materials. We study energy transfer in a linear light-harvesting model to reveal that dimerized geometries with strong electronic coherences within donor and acceptor pairs exhibit significantly improved efficiency, which is in marked contrast to predictions of the classical F\\"orster theory. We reveal that energy tuning due to coherent delocalization of photoexcitations is mainly responsible for the efficiency optimization. This coherence-assisted energy-tuning mechanism also explains the energetics and chlorophyll arrangements in the widely-studied Fenna-Matthews-Olson complex. We argue that a clustered network with rapid energy relaxation among donors and resonant energy transfer from donor to acceptor states provides a basic formula for constructing efficient light-harvesting systems, and the general principles revea...

Ai, Qing; Jin, Bih-Yaw; Cheng, Yuan-Chung

2013-01-01T23:59:59.000Z

479

Simultaneous Velocity Ambiguity Resolution and Noise Suppression for Multifrequency Coherent Doppler Sonar  

Science Conference Proceedings (OSTI)

Coherent Doppler sonar is a useful tool for noninvasive measurement of ocean currents, sediment transport, and turbulence in coastal environments. Various methods have been proposed to separately address two of its inherent limitations: velocity ...

Jeremy Dillon; Len Zedel; Alex E. Hay

2012-03-01T23:59:59.000Z

480

Maximum Likelihood Estimates of Vortex Parameters from Simulated Coherent Doppler Lidar Data  

Science Conference Proceedings (OSTI)

The performance of pulsed coherent Doppler lidar in estimating aircraft trailing wake vortices by scanning across the aircraft flight track is evaluated using Monte Carlo lidar simulations of a simple vortex pair in both a nonturbulent and ...

Rod Frehlich; Robert Sharman

2005-02-01T23:59:59.000Z

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

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

482

On-chip COMA cache-coherence protocol for microgrids of microthreaded cores  

Science Conference Proceedings (OSTI)

This paper describes an on-chip COMA cache coherency protocol to support the microthread model of concurrent program composition. The model gives a sound basis for building multi-core computers as it captures concurrency, abstracts communication and ...

Li Zhang; Chris Jesshope

2007-08-01T23:59:59.000Z

483

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

484

A Fully Conserved Minimal Adjustment Scheme with (T, S) Coherency for Stabilization of Hydrographic Profiles  

Science Conference Proceedings (OSTI)

A new, fully conserved minimal adjustment scheme with temperature and salinity (T, S) coherency is presented for eliminating false static instability generated from analyzing and assimilating stable ocean (T, S) profiles data, that is, from ...

Xidong Wang; Peter C. Chu; Guijun Han; Wei Li; Xuefeng Zhang; Dong Li

2012-12-01T23:59:59.000Z

485

Removing the Laser-Chirp Influence from Coherent Doppler Lidar Datasets by Two-Dimensional Deconvolution  

Science Conference Proceedings (OSTI)

A chirped laser pulse can introduce artifacts into datasets of coherent Doppler wind lidars. At close vicinity of strong signal peaks undesired artificial velocities can be measured and continuous signals can be shifted by a constant factor. It is ...

Johannes Bühl; Ronny Engelmann; Albert Ansmann

2012-08-01T23:59:59.000Z

486

Coherent control of two nuclear spins using the anisotropic hyperfine interaction  

E-Print Network (OSTI)

We demonstrate coherent control of two nuclear spins mediated by the magnetic resonance of a hyperfine-coupled electron spin. This control is used to create a double nuclear coherence in one of the two electron spin manifolds, starting from an initial thermal state, in direct analogy to the creation of an entangled (Bell) state from an initially pure unentangled state. We identify challenges and potential solutions to obtaining experimental gate fidelities useful for quantum information processing in this type of system.

Yingjie Zhang; Colm A. Ryan; Raymond Laflamme; Jonathan Baugh

2011-07-14T23:59:59.000Z

487

A MODEL FOR PRODUCING STABLE, BROADBAND TERAHERTZ COHERENT SYNCHROTRONRADIATION IN STORAGE RINGS  

SciTech Connect

We present a model for producing stable broadband coherent synchrotron radiation (CSR) in the terahertz frequency region in an electron storage ring. The model includes distortion of bunch shape from the synchrotron radiation (SR), enhancing higher frequency coherent emission and limits to stable emission due to a microbunching instability excited by the SR. We use this model to optimize the performance of a source for CSR emission.

Sannibale, Fernando; Byrd, John M.; Loftsdottir, Agusta; Martin, MichaelC.; Venturini, Marco