A short-pulsed compact supersonic helium beam source for plasma diagnostics

Abstract
A short-pulsed (less than 1 ms) compact supersonic helium beam source has been developed for plasma diagnostics purposes. The beam has been characterized experimentally and the results compared with calculations from a simple model that takes into account interaction between the supersonic beam and gas in the region between the nozzle and the skimmer. For a 200 μs driving pulse, a beam of density N > 1 × 1018 m−3 on the axis, a width of D ≈ 1 cm at a distance of 30 cm from the nozzle and a velocity v ≈ 1.8 × 103 m s−1 has been achieved.