CHARACTERISTICS OF PICO-SECOND SINGLE BUNCH AT THE S-BAND LINEAR-ACCELERATOR

Measurement of the bunch structure of a pico-second single bunch was p erformed using a femto-second streak camera at the S-band linear accel erator of the University of Tokyo. The aim of this research is to inve stigate the feasibility of the generation of a femto-second single bun ch at the S-band linac. The details of the bunch structure and energy spectrum of an original single bunch were precisely investigated in se veral operation modes where the RF phases in accelerating tubes and a prebuncher were varied. The femto-second streak camera was utilized to measure the bunch structure by one shot via Cherenkov radiation emitt ed by the electrons in the bunch. Next, an experiment for magnetic pul se compression of the original single bunch was carried out. Pulse sha pes of the compressed bunchs for different energy modulation were also obtained by measuring Cherenkov radiation by one shot using the femto -second streak camera. Prior to the experiment, numerical tracking ana lysis to determine operating parameters for the magnetic pulse compres sion was also done. Measured pulse widths were compared with calculate d ones. Finally, a 2 ps (full width at half maximum; FWHM) single bunc h with an electric charge of 0.3 nC could be generated by the magnetic pulse compression.