Measurement of outgassing rate of charcoal in a steel mesh

For any material to be used in Ultra High vacuum, systems need to be checked for its outgassing rate. Activated charcoal is used as sorbent in a cryopump. Outgassing measurement of charcoal was carried out in Outgassing Measurement System(OGMS) at Institute for Plasma Research (IPR). OGMS(made of 304L steel) uses throughput method and has base outgassing rate (after baking upto 250°C) less than 4 × 10⁻¹² mbar-liter/sec-cm². Charcoal is in the form of small granules hence placed in a pouch made up of SS mesh for finding its outgassing rate. In this article results from experiments carried out to find total gas load from the sample for various temperature cycle is presented.