GLOW-DISCHARGE CLEANING IN PARTICLE ACCELERATORS

Glow discharge (GD) cleaning is well established as an important technique in particle accelerators for achieving the requisite gas desorption coefficients for the necessary operational vacuum levels. Traditionally, argon-oxygen gas mixes are employed as the discharge medium. However, this results in undesirable argon 'hangup' in the residual vacuum. A programme of investigation into various discharge media was therefore undertaken which led to the adoption of a helium-oxygen mix as a suitable discharge medium for our purposes.