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Title: Report on the workshop for potential users of the Argonne Linear Free-Electron Laser Facility (ALFF).

Abstract

On October 30-31, 2003 over 60 scientists gathered at ANL to discuss potential science that could be done with a fully operational user facility dedicated to delivering widely tunable, short pulse, high peak power vacuum ultraviolet light. The charge given to the workshop by J. Murray Gibson, ANL Associate Lab Director for the Advanced Photon Source, included the following two points: (1) What are the scientifically important experiments that can only be done with the proposed ALFF facility? (2) Are the combined ALFF characteristics of pulse energy, tunability, pulse length, and coherence sufficiently unique to justify establishing a user facility at this time? To fulfill this two-point charge, special emphasis was placed by the workshop committee on two goals. First, scientists were invited who work in areas where the lack of powerful, tunable VUV is a limitation to speak about their current research and to speculate on the science that would be uniquely possible with the ALFF. Second, while many of the same scientists have expertise in using lasers and other VUV sources, it was considered crucial to invite scientists explicitly working on the development of tabletop VUV systems. In addition to addressing the second charge question, the purpose ofmore » inviting people with expertise in VUV source development was to raise awareness of the state of the art in tabletop VUV and soft x-ray sources, and to provide a discussion on potential combinations of FEL and tabletop sources (for example, in seeding and pump-probe arrangements). This report briefly summarizes the talks presented at this workshop and highlights some of the user needs that this facility can fulfill. The full presentations may be accessed online at www.aps.anl.gov/conferences/ALFFworkshop. The workshop was organized around four working groups to focus the discussions among scientists with similar backgrounds. These groups were: Atomic, Molecular, Optical (AMO) and Chemical Physics;. Cosmochemistry and Geochemistry; Materials Science; and Biology and Environmental Science. A plenary session included a background talk on the LEUTL followed by a lecture from one scientist in each of these areas. The background, presented by Steve Milton, delineated the existing FEL capabilities as well as the nature of the proposed upgrade, specifically the interleaving operations that will allow for a large number of user beam hours, similar to the level that the APS storage ring users now enjoy. A higher repetition rate and a shift in tuning range to shorter wavelengths was also proposed.« less

Authors:
Publication Date:
Research Org.:
Argonne National Lab., IL (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
823333
Report Number(s):
ANL/ASD/RP-113017
TRN: US0401688
DOE Contract Number:
W-31-109-ENG-38
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 5 Apr 2004
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ADVANCED PHOTON SOURCE; ANL; BIOLOGY; COSMOCHEMISTRY; FREE ELECTRON LASERS; GEOCHEMISTRY; LASERS; PEAK LOAD; PHYSICS; TUNING; WAVELENGTHS; X-RAY SOURCES

Citation Formats

Kim, K. J.. Report on the workshop for potential users of the Argonne Linear Free-Electron Laser Facility (ALFF).. United States: N. p., 2004. Web. doi:10.2172/823333.
Kim, K. J.. Report on the workshop for potential users of the Argonne Linear Free-Electron Laser Facility (ALFF).. United States. doi:10.2172/823333.
Kim, K. J.. Mon . "Report on the workshop for potential users of the Argonne Linear Free-Electron Laser Facility (ALFF).". United States. doi:10.2172/823333. https://www.osti.gov/servlets/purl/823333.
@article{osti_823333,
title = {Report on the workshop for potential users of the Argonne Linear Free-Electron Laser Facility (ALFF).},
author = {Kim, K. J.},
abstractNote = {On October 30-31, 2003 over 60 scientists gathered at ANL to discuss potential science that could be done with a fully operational user facility dedicated to delivering widely tunable, short pulse, high peak power vacuum ultraviolet light. The charge given to the workshop by J. Murray Gibson, ANL Associate Lab Director for the Advanced Photon Source, included the following two points: (1) What are the scientifically important experiments that can only be done with the proposed ALFF facility? (2) Are the combined ALFF characteristics of pulse energy, tunability, pulse length, and coherence sufficiently unique to justify establishing a user facility at this time? To fulfill this two-point charge, special emphasis was placed by the workshop committee on two goals. First, scientists were invited who work in areas where the lack of powerful, tunable VUV is a limitation to speak about their current research and to speculate on the science that would be uniquely possible with the ALFF. Second, while many of the same scientists have expertise in using lasers and other VUV sources, it was considered crucial to invite scientists explicitly working on the development of tabletop VUV systems. In addition to addressing the second charge question, the purpose of inviting people with expertise in VUV source development was to raise awareness of the state of the art in tabletop VUV and soft x-ray sources, and to provide a discussion on potential combinations of FEL and tabletop sources (for example, in seeding and pump-probe arrangements). This report briefly summarizes the talks presented at this workshop and highlights some of the user needs that this facility can fulfill. The full presentations may be accessed online at www.aps.anl.gov/conferences/ALFFworkshop. The workshop was organized around four working groups to focus the discussions among scientists with similar backgrounds. These groups were: Atomic, Molecular, Optical (AMO) and Chemical Physics;. Cosmochemistry and Geochemistry; Materials Science; and Biology and Environmental Science. A plenary session included a background talk on the LEUTL followed by a lecture from one scientist in each of these areas. The background, presented by Steve Milton, delineated the existing FEL capabilities as well as the nature of the proposed upgrade, specifically the interleaving operations that will allow for a large number of user beam hours, similar to the level that the APS storage ring users now enjoy. A higher repetition rate and a shift in tuning range to shorter wavelengths was also proposed.},
doi = {10.2172/823333},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Apr 05 00:00:00 EDT 2004},
month = {Mon Apr 05 00:00:00 EDT 2004}
}

Technical Report:

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  • In this environmental assessment (EA), the US Department of Energy (DOE) reports the results of an analysis of the potential environmental impacts from a proposed change in operating parameters of the Continuous Electron Beam Accelerator Facility (CEBAF), and operation of the Free Electron Laser (FEL) facility beyond the initial demonstration period. With this proposal, DOE intends to increase CEBAF operating range from its current operating maximum beam energy of 4.0 GeV [giga-(billion) electron volts] to 8.0 GeV at a beam power of no greater than 1,000 kW [1 megawatt (MW)], its maximum attainable level, based on current technology and knowledge,more » without significant, costly equipment modifications. DOE has prepared an EA for this action to determine the potential for adverse impacts from operation of CEBAF and the FEL at the proposed levels. Changing the operating parameters of CEBAF would require no new major construction and minor modifications to the accelerator, its support systems, the FEL, and onsite utility systems. Modifications and performance improvements would be made to (1) the accelerator housed in the underground tunnels, (2) its support systems located in the above ground service buildings, and (3) the water and equipment cooling systems both in the tunnel and at the ground surface. All work would be performed on previously disturbed land and in, on, or adjacent to existing buildings, structures, and equipment. With the proposed action, the recently constructed FEL facility at the Jefferson Lab would operate in concert with CEBAF beyond its demonstration period and up to its maximum effective electron beam power level of 210 kW. In this EA, DOE evaluates the impacts of the no-action alternative and the proposed action alternative. Alternatives considered, but dismissed from further evaluation, were the use of another accelerator facility and the use of another technology.« less
  • The underlying theory of a high gain free electron laser (FEL) has existed for two decades [1-2], but it is only in the last few years that these novel radiation sources have been realized experimentally. Several high gain FELs have successfully reached saturation in the infrared, visible and the VUV portion of the spectrum: the High Gain Harmonic Generation (HGHG) free electron lasers [3] at BNL and the Self Amplified Spontaneous Emission (SASE) FELs at LEUTL, VISA and TTF [4-6]. The outstanding challenges for future FELs are to extend high gain FELs to the X-ray regime, improve the longitudinal coherencemore » of the radiation using seeded FEL schemes and generate ultrashort pulses (<100 fs). The National Synchrotron Light Source (NSLS) of the Brookhaven National Laboratory (BNL) sponsored a Seeded X-ray Free Electron Laser Workshop on December 13-14, 2002 to explore these challenging issues. Representatives from BNL, DESY, LBNL, SLAC and UCLA made presentations on the novel schemes under consideration at their laboratories. Workshop participants had a lively discussion on the feasibility, performance and R&D issues associated with the seeded XFEL schemes. An improvement of the electron beam quality will certainly be necessary to drive the XFEL. Self-seeding SASE, cascaded HGHG, and SASE pulse compression FELs show the most promise for producing short pulse X-rays. Of these, only the self-seeded and HGHG schemes generate longitudinally coherent radiation. While the pulse length in the self-seeded scheme is determined by the electron bunch length ({approx}100 fs), the pulse length in the HGHG scheme is determined by the short pulse seed laser, and so can be much shorter ({approx} 20 fs).« less
  • This paper presents a self-consistent non-linear treatment of the finite transverse dimensional effects associated with (1) the wiggler field, (2) the electron beam and (3) the radiation beam of the free electron laser (FEL) in a steady state amplifying configuration. Our formulation incorporates various efficiency enhancement schemes. A linearly polarized magnetic wiggler is used for our formulation. The inherent gradient of the magnetic wigglers in the transverse direction introduces betatron oscillations, which cause an increase in the effective axial beam temperature. The radiation beam in the presence of the electron beam and the magnetic wiggler experience diffraction as well asmore » refraction effects. We find that the 3-D effects can lead to substantial differences in the effects compared to the 1-D theory. Finally a 3-D numerical illustration of a 10.6 micron FEL is given.« less
  • The general non-linear self-consistent equations describing the free electron laser (FEL) in the steady state amplifying configuration is derived with the space charge effects and all the efficiency enhancement schemes: (1) a spatially varying wiggler amplitude and/or period and (2) a D.C. electric field E sub DC (z) = (-(del phi sub DC)/del z)e-carat sub z. All the efficiency enhancement schemes are shown to be somewhat equivalent. For a variable period magnetic wiggler, the FEL equations can be appropriately normalized to a three parameter set of coupled equations. All operating regimes are covered by these normalized equations. The condition formore » space charge to be unimportant is given. In the absence of the space charge effects, the three parameter set of equations reduces to a two parameter set. The inclusion of additional efficiency enhancement schemes increases the number of parameters to describe the FEL. Curves showing the efficiency, radiation amplitude and growth rate will be presented.« less
  • This paper deals primarily with 3-D effects and efficiency enhancement methods in a steady state FEL amplifier configuration. We treat finite transverse dimension effects associated with (1) the wiggler field, (2) electron beam, and (3) radiation beam. Our formulation includes efficiency enhancement schemes such as spatially contouring the wiggler field as well as accelerating the electron beam. Finally, a 3-D example of a 10.6 microns FEL with enhanced efficiency is given.