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Title: Electron beam bunch length characterizations using incoherent and coherent radiation on the APS SASE FEL project.

Conference ·
OSTI ID:11807

The Advanced Photon Source (APS) injector linac has been reconfigured with a low-emittance rf thermionic gun and a photocathode (PC) rf gun to support self-amplified spontaneous emission (SASE) free-electron laser (FEL) experiments. One of the most critical parameters for optimizing SASE performance (gain length) is the electron beam peak current, which requires a charge measurement and a bunch length measurement capability. We report here initial measurements of the latter using both incoherent optical transition radiation (OTR) and coherent transition radiation (CTR), A visible light Hamarnatsu C5680 synchroscan streak camera was used to measure the thermionic rf gun beam's bunch length ({sigma} {approximately}2 to 3ps) via OTR generated by the beam at 220 MeV and 200 mA macropulse average current. In addition, a CTR monitor (Michelson Interferometer) based on a Golay cell as the far infrared (FIR) detector has been installed at the 40-MeV station in the beamline. Initial observation s of CTR signal strength variation with gun a-magnet current and interferograms have been obtained. Progress in characterizing the beam at these locations and a comparison to other bunch length determinations will be presented.

Research Organization:
Argonne National Lab., IL (US)
Sponsoring Organization:
US Department of Energy (US)
DOE Contract Number:
W-31109-ENG-38
OSTI ID:
11807
Report Number(s):
ANL/ASD/CP-99024; TRN: US0103685
Resource Relation:
Conference: 21st International Free Electron Laser Conference, Hamburg (DE), 08/23/1999--08/28/1999; Other Information: Supercedes report DE00011807; PBD: 28 Aug 1999
Country of Publication:
United States
Language:
English