A high flux metastable atomic discharge source with three-dimensional translation

Abstract

We present a new apparatus for the generation of a high flux metastable atomic beam. This source has provided a high flux of metastable helium and argon atoms via a cold cathode discharge with fluxes for metastable helium of up to 9 × 1014 sr-1 s-1. This new source can be translated in three dimensions whilst under vacuum and cooled to 77 K. Experimental results demonstrate that the distance of the source nozzle from the skimmer is important in obtaining the optimum flux. Under typical operating conditions, this optimal distance is 9–10 mm using He. Time-of-flight spectra show that for Ar the average thermal velocity of the beam is 540 m s-1 and can be reduced to 330 m s-1 by cooling the source with liquid nitrogen.