AMPLIFICATION OF SPONTANEOUS EMISSION WITH 2 HIGH-BRIGHTNESS ELECTRONBUNCHES OF THE ISIR LINAC

Recently, self-amplified spontaneous emission (SASE) has been observed at wavelengths of 20 and 40 mum with high-brightness single-bunch ele ctron beams of the 38 MeV L-band linear accelerator (linac) at The Ins titute of Scientific and Industrial Research in Osaka University. A st udy has been made to generate two electron bunches for amplifying the SASE with another electron bunch under an oscillator configuration at a wavelength of 40 mum. A grid pulser of the electron gun has been dev eloped for generating two electron bunches at the interval correspondi ng to the round-trip time of an optical cavity. The total charge of th e electrons and the energy spread of the beam accelerated at an energy of 17.1 MeV are 40 nC and 2% (FWHM), respectively. After further opti mization of the conditions of the microwave supplied to each component of the accelerator system, experiments of two-bunch amplification wil l be performed.