The Production of Intense Ion Beams in a Mass Spectrometer

Abstract

A simple 60° mass spectrometer has been built for the production of intense ion beams. Ions are produced by allowing an electron beam collimated by a transverse magnetic field to bombard the vapor issuing from a furnace. By adjusting conditions properly an arc may be struck and total ion currents of 1 to 2 ma could be obtained from the source when the accelerating voltage applied was 15 kev. The collected isotopes were completely resolved, and a total current of 0.3 ma for the several isotopes at the final collector was observed. Because of gas focusing at the operating pressure, space charge effects did not seriously affect the resolution and a resolving power of 1/100 could be obtained. In a 14-hr. run 6.5 mg of separated zinc isotopes were collected. Preliminary results with magnesium, as well as other solids, indicated that many other substances could be separated without modifying the apparatus. Improvements which would permit higher yields are suggested.