Testing of non-evaporable getter pills for standardization of their pumping performance testing method

Abstract

The pumping characteristics of non-evaporable getter (NEG) pills were measured according to ASTM F 798–97 (2002) for standardizing their pumping performance testing method. St707 (Zr–V–Fe alloy) and ZAO (Zr–V–Ti–Al alloy) were used as samples. The repeatability of three measurements for the NEGs was within 12% for H2 and 5% for CO, respectively, except for the first measurement. The data scatter of pumping speed per unit nominal area of the St707 which had different years of fabrication and sizes, was within 30% for H2 and within a factor of 2 for CO, whereas that of the ZAO was 3 times larger at maximum than that of the St707 for both H2 and CO. Our results were compared with those from previous studies and calculation models.