Reduction of outgassing rate from residual gas analyzers for extreme high vacuum measurements

One problem associated with partial pressure measurement in an extreme high vacuum region is outgassing from the residual gas analyzer (RGA) itself. In order to reduce the outgassing rate from the RGA, the temperature of the filament should be lowered, and the heat generated around the ion source of the RGA should be dissipated in the atmosphere. We modified a RGA and reduced its outgassing rate to 1.5×10−12 Pa m3/s. We also determined the partial outgassing rate from the ion source and chamber quantitatively and found that hydrogen constituted more than 99% of the outgassing from the stainless steel.