Response of a wireline pickup for subnanosecond electron beam pulses

The response of a wireline-type beam monitor was measured for electron beams with energies of 28 MeV and pulsewidths of 20 ps from an electron linear accelerator. The output waveform from the wireline pickup was calculated according to the general formulation for responses of beam monitors based on electromagnetic interaction. In the calculations, a transfer function H(ω) and an effective length l _eff are introduced to express all the effects not included in the analysis. The function H(ω) is assumed to be Gaussian, and the FWHM of H(ω) and l_eff is experimentally determined. The effects of the termination, wireline length, height, and angle between the wireline and the beam direction are discussed. The test supported the analysis and, for the standard pickup, a charge sensitivity of 20 V/nC and an FWHM of H(ω) of 55 ps are obtained