Cold Electron Sources for Mass Spectrometric Applications

Abstract

Cold electron sources have been studied with particular emphasis on mass spectrometric application. In these sources a relatively weak current from a primary emitter was amplified by an electron multiplier to provide sufficient electron current to ionize neutral gas molecules. The final designs of the cold sources use tantalum photocathodes powered by simulated sunlight as primary electron sources. The sources are highly efficient, consume negligible power, have minimal outgassing and gettering effects, and exhibit considerably less short-term emission fluctuations than a temperature-limited thermionic emitter. These devices would be well suited to calibration work and space flight instrumentation.

A Summary of Instrumentation

“…This is another area in which fundamental studies will greatly benefit from further development of instrumentation. Testerman et al (1965) have studied cold electron sources with emphasis on their use in mass spectrometric applications. The designs and the properties of this source have been thoroughly described, and the suggestion has been made that these sources could find application in calibration work and in space flight instrumentation where, of course, the source temperature might vary over a tremendous range.…”