Use of Scanning Slits for Obtaining the Current Distribution in Electron Beams

Abstract

In axially symmetric electron beams, the current density (as a function of radius) may be rather easily related to the current through a narrow slit (as a function of slit position) by means of an integral equation. A similar equation applies to scanning by a straightedge. In this paper, the solution of the integral equation is obtained and a simple technique for rapid numerical evaluation of the resulting ordinary equation is included. The relations derived are of particular interest in the large number of cases where the mechanical simplicity of slit or straightedge scanning makes these methods preferable to the more common pinhole method. The resolving powers for slit and pinhole scans are compared.