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Title: An Injector Test Facility for the LCLS

Abstract

SLAC is in the privileged position of being the site for the world's first 4th generation light source as well as having a premier accelerator research staff and facilities. Operation of the world's first x-ray free electron laser (FEL) facility will require innovations in electron injectors to provide electron beams of unprecedented quality. Upgrades to provide ever shorter wavelength x-ray beams of increasing intensity will require significant advances in the state-of-the-art. The BESAC 20-Year Facilities Roadmap identifies the electron gun as ''the critical enabling technology to advance linac-based light sources'' and recognizes that the sources for next-generation light sources are ''the highest-leveraged technology'', and that ''BES should strongly support and coordinate research and development in this unique and critical technology''.[1] This white paper presents an R&D plan and a description of a facility for developing the knowledge and technology required to successfully achieve these upgrades, and to coordinate efforts on short-pulse source development for linac-based light sources.

Authors:
 [1];
  1. (ed.)
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
900991
Report Number(s):
SLAC-TN-07-005
TRN: US200713%%248
DOE Contract Number:
AC02-76SF00515
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCELERATORS; ELECTRON BEAMS; ELECTRON GUNS; ELECTRONS; FREE ELECTRON LASERS; LIGHT SOURCES; STANFORD LINEAR ACCELERATOR CENTER; WAVELENGTHS; Accelerators,ACCPHY

Citation Formats

Colby, E.,, and /SLAC. An Injector Test Facility for the LCLS. United States: N. p., 2007. Web. doi:10.2172/900991.
Colby, E.,, & /SLAC. An Injector Test Facility for the LCLS. United States. doi:10.2172/900991.
Colby, E.,, and /SLAC. Wed . "An Injector Test Facility for the LCLS". United States. doi:10.2172/900991. https://www.osti.gov/servlets/purl/900991.
@article{osti_900991,
title = {An Injector Test Facility for the LCLS},
author = {Colby, E., and /SLAC},
abstractNote = {SLAC is in the privileged position of being the site for the world's first 4th generation light source as well as having a premier accelerator research staff and facilities. Operation of the world's first x-ray free electron laser (FEL) facility will require innovations in electron injectors to provide electron beams of unprecedented quality. Upgrades to provide ever shorter wavelength x-ray beams of increasing intensity will require significant advances in the state-of-the-art. The BESAC 20-Year Facilities Roadmap identifies the electron gun as ''the critical enabling technology to advance linac-based light sources'' and recognizes that the sources for next-generation light sources are ''the highest-leveraged technology'', and that ''BES should strongly support and coordinate research and development in this unique and critical technology''.[1] This white paper presents an R&D plan and a description of a facility for developing the knowledge and technology required to successfully achieve these upgrades, and to coordinate efforts on short-pulse source development for linac-based light sources.},
doi = {10.2172/900991},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Mar 14 00:00:00 EDT 2007},
month = {Wed Mar 14 00:00:00 EDT 2007}
}

Technical Report:

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  • The parameters for a 30 GeV test beam are outlined for use with an undulator in the FFTB tunnel where the LCLS will eventually be housed. It is proposed to use the SLAC linac and damping rings in their present mode of operation for PEP II injection, where 30 GeV beams are also delivered at 10 Hz to the FFTB. High peak currents are obtained with the addition of a second bunch compressor in the linac. In order to minimize the synchrotron radiation induced emittance growth in the bunch compressor it is necessary to locate the new bunch compressor atmore » the low-energy end of the linac, just after the damping rings. The bunch compressor is a duplicate of the LCLS chicane-style bunch compressor. This test beam would provide an exciting possibility to test LCLS undulator sections and provide a unique high-brightness source of incoherent X-rays and begin developing the LCLS experimental station. The facility will also act as a much needed accelerator test bed for the production, diagnostics and tuning of very short bunches in preparation for the LCLS after the photo injector is commissioned.« less
  • The CLIC Test Facility (CTF3) is an intermediate step to demonstrate the technical feasibility of the key concepts of the new RF power source for CLIC. CTF3 will use electron beams with an energy range adjustable from 170 MeV (3.5 A) to 380 MeV (with low current). The injector is based on a thermionic gun followed by a classical bunching system embedded in a long solenoidal field. As an alternative, an RF photo-injector is also being studied. The beam dynamics studies on how to reach the stringent beam parameters at the exit of the injector are presented. Simulations performed withmore » the EGUN code showed that a current of 7 A can be obtained with an emittance less than 10 mm.mrad at the gun exit. PARMELA results are presented and compared to the requested beam performance at the injector exit. Sub-Harmonic Bunchers (SHB) are foreseen, to switch the phase of the bunch trains by 180 degrees from even to odd RF buckets. Specific issues of the thermionic gun and of the SHB with fast phase switch are discussed.« less
  • Damage threshold fluences for several optical components were measured at three wavelengths using the injector laser at SSRL's Gun Test Facility. Measurements were conducted using the fundamental ir wavelength at 1053 nanometers and harmonics at 526 nm and 263 nm with 3.4ps pulses (1/e{sup 2} full width intensity); ir measurements were also conducted with 850 ps pulses. Practical surfaces relevant to the laser system performance are emphasized. Damage onset was evidenced by an alteration of the specular reflection of a cw probe laser (650 nm) from the irradiated region of the target surface. For the case of stretched ir pulses,more » damage to a Nd:glass rod was observed to begin at a site within the bulk material and to progress back toward the incident surface.« less
  • An analysis of the BNL photocathode (1-1/2 cell) Gun'' operating at 2856 MHZ, is presented. The beam parameters including beam energy, and emittance are calculated. A review of the Gun parameters and full input and output of our analysis with program PARMELA, is given in Section 2, some of our results, are tabulated. The phase plots and the beam parameters, at downstream ends of the elements, from cathode through the cavity, first cell is labeled as element 2; and second cell is labeled as element to the exit of the GUN. The analysis was made for 3 cases, using threemore » different initial values (EO) for the average accelerating gradient (MV/m), for comparison with previous works. For illustration, the field obtained with program SUPERFISH is given, and conclusion including shunt impedances obtained for the cells and the cavity are given in Section 6. PARMELA is used as a standard design program at ATF. At the request of some of the users of program PARMELA, this request of some of the users of program PARMELA, this report include and illustrates some of our data, in the input and output format of the program PARMELA. 5 refs., 7 figs., 3 tabs.« less