Abstract
A simple ion gun, which efficiently operates at the pressure range from 13.33-1.33 mPa (10-4 to 10-5 Torr) and in the energy range from 250 to 1000 eV, has been devised for ion scattering spectroscopy applications. Mass analyses show that when the source is operated with 99.99% grade gases (Ar, Ne and He) the ratio of the doubly-charged ion to the singly-charged one for Ne and Ar is 0.02 and 0.16, respectively, and the amount of other impurities which consist of CO+ and H2O+ is about 2% of the total ions. Intensity curves of singly-charged ions in each case have a broad maximum at the pressure around 53.32 mPa (4*10-4 Torr). The energy spread is found to be 0.99 eV for He+ ion beam by extrapolation to zero beam energy. An application to ISS study is also presented.