Time-resolved beam energy measurement of short electron beam bunches with a longitudinal velocity tilt

Both electrostatic retarding and deflecting energy analyzers have been employed to measure the time-resolved beam energy of short (30 to 50 ns pulse duration) and space-charge dominated (40 mA and 2.5 keV) electron bunches with longitudinal momentum tilts. The time resolutions are better than a half nanosecond. The energy resolutions are better than 0.3 % for the retarding analyzer and 2.5 % for the deflecting analyzer. In this paper basic operating principles are briefly described. Several experimental results are presented. Calibrations and measured energy width are given. Finally the performances of both devices will be summarized.