High‐resolution retarding potential analyzer

A simple electrostatic retarding potential analyzer (RPA) configuration is described that gives a true measure of charged particle energy irrespective of the angle of incidence of the particles. The device has an inherently high energy resolution (ΔE/E<0.01). The device eliminates errors in particle energy measurement usually associated with planar gridded RPAs. Electrostatic models and results from an experimental prototype are presented.