Monochromatic coherent transition and diffraction radiation from a relativistic electron bunch train

Electron beams of most accelerators have a bunched structure and are synchronized with the accelerating RF field. Due to modulation of the electron beam with frequency v[RF] one can expect to observe resonances with frequencies vk= k·v[RF] in radiation spectrum generated via any spontaneous emission mechanism (k is an integer and the resonance order). In this paper we present the results of spectral measurements of coherent transition radiation (CTR) generated by an electron bunch train from the Tomsk microtron with v[RF]=2.63GHz in the spectral frequency range from 8 to 35 GHz. We also measured the spectrum of coherent diffraction radiation and demonstrated that the observed spectra in both cases consist of monochromatic lines. For spectral measurements the Martin-Puplett interferometer with spectral resolution of 800 MHz (FWMH) was employed. Using a waveguide frequency cut-off we were able to exclude several spectral lines to observe higher resonance orders of up to k=7

Characteristics of Smith-Purcell radiation in millimeter wavelength region

Investigations of the Smith-Purcell radiation (SPR) were began with non-relativistic electron beams with some unexpected experimental results. Further the experimental investigations were performed with relativistic electron beams for application to beam diagnostics. Large discrepancy between different theoretical models significantly increases the role of experimental studies of this phenomenon. In this report we present some problems and features of experimental investigations of SPR in millimeter wavelength region. The problems of prewave zone and coherent effects are considered. The shadowing effect, focusing of radiation using a parabolic SPR target and effect of inclination of target strips were investigated with moderately relativistic electron beam

SUB-MICROMETER RESOLUTION TRANSVERSE ELECTRON BEAM SIZE MEASUREMENT SYSTEM BASED ON OPTICAL TRANSITION RADIATION

Optical Transition Radiation (OTR) appears when a charged particle crosses a boundary between two media with different dielectric properties has widely been used as a tool for transverse profile measurements of charged particle beams in numerous facilities worldwide. The resolution of the conventional monitors is defined by the Point Spread Function (PSF) dimension - The source distribution generated by a single electron and projected by an optical system onto a screen. For small electron beam dimensions, the PSF form significantly depends on various parameters of the optical system like diffraction of the OTR tails, spherical and chromatic aberrations, etc. In our experiment we managed to create a system which can practically measure the PSF distribution and using a new self-calibration method we are able to calculate transverse electron beam size. Here we represent the development, data analysis and novel calibration technique of a sub-micrometer electron beam profile monitor based on the measurements of the PSF shape, which visibility is sensitive to sub-micrometer electron beam dimensions. Copyright © 2011 by IPAC'11/EPS-AG