PRECISE MEASUREMENT OF A SUBPICOSECOND ELECTRON SINGLE BUNCH BY THE FEMTOSECOND STREAK CAMERA

Precise measurement of a subpicosecond electron single bunch by the fe mtosecond streak camera is presented. The subpicosecond electron singl e bunch of energy 35 MeV was generated by the achromatic magnetic puls e compressor at the S-band linear accelerator of Nuclear Engineering R esearch Laboratory (NERL), University of Tokyo. The electric charge pe r bunch and beam size are 0.5 nC and the horizontal and vertical beam sizes are 3.3 and 5.5 mm (full width at half maximum; FWHM), respectiv ely. Pulse shape of the electron single bunch is measured via Cherenko v radiation emitted in air by the femtosecond streak camera. Optical p arameters of the optical measurement system were optimized based on mu ch experiment and numerical analysis in order to achieve a subpicoseco nd time resolution. By using the optimized optical measurement system, the subpicosecond pulse shape, its variation for the differents rf ph ases in the accelerating tube, the jitter of the total system and the correlation between measured streak images and calculated longitudinal phase space distributions were precisely evaluated. This measurement system is going to be utilized in several subpicosecond analyses for r adiation physics and chemistry. (C) 1998 Elsevier Science B.V. All rig hts reserved.