GENERATION AND APPLICATION OF HIGH-BRIGHT NESS SUBPICOSECOND ELECTRONSINGLE BUNCH

Ultrafast and basic processes of interaction of radiation with matter, such as excitation, relaxation, vibration and ionization of atoms and molecules, and radiation damage, occur in a femtosecond time domain. Aiming at investigation of such phenomena, a subpicosecond (0.5-0.9ps) 37 MeV electron single bunch was generated at the S-band linear accel erator of Nuclear Engineering Research Laboratory, University of Tokyo . An original single bunch with a pulse width [full width at half maxi mum (FWHM)] of about 10 ps was successfully compressed to a subpicosec ond time domain by magnetic pulse compression. The magnetic pulse comp ression using the nonlinear energy modulation was developed to achieve the most effective compression. Then an achromatic magnetic pulse com pressor was constructed to focus the beam spot and increase the charge density. Furthermore, the operation mode of the 90 keV thermionic ele ctron gun was optimized to enhance a brightness of the subpicosecond s ingle bunch. Finally, a 900 fs single bunch containing 1.0 nC per bunc h was achieved. Subpicosecond pulse-radiolysis experiments are under w ay by using the subpicosecond electron single bunch. Further, we have proposed and designed a femtosecond quantum phenomena research facilit y to investigate ultrafaster phenomena in radiation physics, chemistry , material science and electromagnetics.