Nonevaporable getter coating chambers for extreme high vacuum

Techniques for nonevaporable getter (NEG) coating a large diameter chamber are presented along with vacuum measurements in the chamber using several pumping configurations, with base pressure as low as 1.56 × 10−12 Torr (N2 equivalent) with only a NEG coating and a small ion pump. The authors then describe modifications to the NEG coating process to coat complex geometry chambers for ultracold atom trap experiments. Surface analysis of NEG coated samples is used to measure the composition and morphology of the thin films. Finally, pressure measurements are compared for two NEG coated polarized electron source chambers: the 130 kV polarized electron source at Jefferson Lab and the upgraded 350 kV polarized electron source, both of which are approaching or within the extreme high vacuum range, defined as P < 7.5 × 10−13 Torr.