Hydrogen pumping characteristics of dry pumps

Dry pumps are widely used in fusion research devices, where hydrogen is the main working gas, to attain ultraclean vacuums. However, there is not sufficient information on the hydrogen pumping characteristics of the dry pumps, which may cause a difficulty in determining whether a dry pump of a particular type can be used or not in a fusion experiment system at a specific operation condition. In this article, the experimental setup, measurement procedures, and experimental results on the pumping characteristics of dry pumps operated in our laboratory, especially for the hydrogen gas, are reported and discussed.