MEASUREMENT OF FEMTOSECOND ELECTRON BUNCHES USING A RF ZERO-PHASING METHOD

Bunch lengths as shea as 84 fs (rms) have been measured at Jefferson L aboratory using a rf zero-phasing technique. To the best of our knowle dge, this is the first accurate measurement of the longitudinal distri bution function in this regime. In this paper, an analytical approach for computing the longitudinal distribution function and bunch length is described for arbitrary longitudinal and transverse distributions f or the case where the intrinsic energy spread of the bunch is,small co mpared to the correlated energy spread imparted by zero-phasing caviti es. The measurement results are presented, which are in excellent agre ement with numerical simulations.