BEAM EMITTANCE DETERMINATION USING OPTICAL TRANSITION RADIATION

Optical transition radiation produced by an electron beam, with an energy scaling from 80 keV to 20 MeV, on alu-minium and silver foils, has been observed in backward direction. Count rates of photons were measured for three orders of magnitude of the electron energy. Emittance has been determined at 4.8 MeV, by the three gradient method, varying the spot size on Al foil with a solenoidal lens. Images of beam spots were observed on a sensitive CCD camera. A dedicated program on a PC computer allowed achievement of equidensity domains, X-Y profiles. Accurate determination of beam width provided emittance values which compared with those obtained with the tra-ditional moving slit method present reasonable agreement.