Studies of Adsorption Characteristics of Activated Carbons down to 4.5K for the Development of Cryosorption Pumps

摘要

Pumps based on cryosorption are the only solution to pump helium, hydrogen in the high magnetic field andrnhigh temperature environment of a tokamak. Activated carbons are the most suitable adsorbents for thernabove. For this development, the knowledge of their adsorption characteristics of activated carbons in thernrange from 4.5 K to 77 K is needed, but is scarce in the literature. Towards this, an experimental setup isrndeveloped for studies of adsorbents down to 4.5 K, which uses a commercial micropore analyzer operating atrn77K along with a two stage GM Cryocooler for cooling the sample down to 4.5 K. This work presents thernadsorption isotherms of several activated carbons from 4.5 K to 10 K for helium adsorbate along with theirrnpore size distributions and surface areas. The effect of adhesives (used in bonding the activated carbons tornpanel) on the adsorption characteristics are also discussed. These results are useful in the development ofrncryosorption pumps.