Performance enhancement study of an electrostatic Faraday cup detector

Faraday cups (FCs) have long been used to measure charged particle beam currents in experiments that seek to determine cross-sections in energetic particle collisions. The reliable operation of a FC as a detector depends on the ability of the device to recapture the electrons ejected when energetic particles strike its interior metal surfaces. We have conducted comparative performance studies of a traditional cylindrically-symmetric, electrostatic-based FC versus an alternative design in which the cylindrical symmetry is broken. The purpose of the alternative design is to generate a transverse electric field to recapture the ejected (secondary and tertiary) electrons. The alternate FC design is shown to be superior in its ability to recapture these electrons, including those having kinetic energies greater than the potential energy barrier determined by the repeller voltage applied to the FC.