A Faraday Cup with Multiple Internal Filters and a Primary Current Monitor for Characterizing High Dose Pulsed Electron Beams.

A Faraday cup with multiple internal filters has been developed for characterizing intense pulsed electron beams. Four points on the charge deposition profile can be obtained on a single pulse. These data, in conjunction with the diode voltage histroy and Monte Carlo electron transport calculations, can be used to establish the average transverse beam energy mean angle of incidence and hence the energy deposition profile. Performance of the device was demonstrated for a 5kJ, 600keV beam that was transported from the diode using longitudinal magnetic fields and that produced peak doses in excess of 200 calgm. A primary current monitor was also developed. This thin foil device, which is inserted between the diode and a target, measures the transported primary beam current passing through the foils, but not the low energy beam plasma return current. The present design caused attenuation of on the order of one-third of the beam energy. Three beam conditions obtained on the Model 225W Pulserad were characterized using these devices. The data confirm the absence of electron albedo in magnetically transported beams. Data obtained to investigate the effects of apertures on beam behavior indicate that apertures of 0.5-inch diameter or less lead to current waveforms that differ from the total current.