The Production of Proton Beams

Abstract

An account is given of further work on capillary ion sources of the diffusion type. Both metal and glass capillaries have been investigated. The performance of the metal sources is affected by surface conditions which are difficult to control. The average proton yield from these sources is about ten percent. It was found that the yield could be increased to about fifty percent by coating the surface with phosphorus pentoxide. Sources constructed of Pyrex have a proton yield of about sixty percent and also greater stability in operation, as well as certain other advantages. Various characteristics of the output of both types of source are described as functions of the source geometry, arc current, and other variables.