Generation and Use of Coherent Transition Radiation from Short Electron Bunches

Technical Report · Tue Aug 28 00:00:00 EDT 2001

DOI:https://doi.org/10.2172/787223· OSTI ID:787223

Settakorn, Chitrlada ^[1]

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1. SLAC

When accelerated, an electron bunch emits coherent radiation at wavelength longer than or comparable to the bunch length. The coherent radiation intensity scales with the square of the number of electron per bunch and its radiation spectrum is determined by the Fourier Transform of the electron bunch distribution squared. At the SUNSHINE (Stanford University Short Intense Electron Source) facility, electron bunches can be generated as short as {sigma}{sub z} = 36 {micro}m (120 femtosecond duration) and such bunches can emit coherent radiation in the far-infrared. Since a typical number for the electron population in a bunch is 10{sup 8}-10{sup 9}, the coherent radiation intensity is much higher than that of incoherent radiation as well as that of a conventional far-infrared radiation source. This concentrates on coherent transition and diffraction radiation from short electron bunches as a potential high intensity far-infrared radiation source and for sub-picosecond electron bunch length measurements. Coherent transition radiation generated from a 25 MeV beam at a vacuum-metal interface is characterized. Such a high intensity radiation source allows far-infrared spectroscopy to be conducted conveniently with a Michelson interferometer and a room temperature detector. Measurements of the refractive index of silicon are described to demonstrate the possibilities of far-infrared spectroscopy using coherent transition radiation Coherent diffraction radiation, which is closely related to coherent transition radiation, can be considered as another potential FIR radiation source. Since the perturbation by the radiation generation to the electron beam is relatively small, it has the advantage of being a nondestructive radiation source.

• Research Organization: Stanford Linear Accelerator Center, Menlo Park, CA (US)
• Sponsoring Organization: USDOE Office of Energy Research (ER) (US)
• DOE Contract Number: AC03-76SF00515
• OSTI ID: 787223
• Report Number(s): SLAC-R-576
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
BEAM BUNCHING
COHERENT RADIATION
ELECTRON BEAMS
ELECTRON SOURCES
MICHELSON INTERFEROMETER
REFRACTIVE INDEX
TRANSITION RADIATION
USES