Vg. Kolobrodov et al., ADSORPTION OF HELIUM AT 4,2-K BY SOME ADSORBENTS USED FOR HE-3 PUMPING IN LOW-TEMPERATURE CRYOSTATS, Fizika nizkih temperatur, 19(3), 1993, pp. 331-335
A stand is developed to study the pumping characteristics of cryopumps
for internal He-3 pumping in low-temperature cryostats. Isotherms of
He-4 adsorption at 4.2 K were measured for three carbon adsorbents (co
mmercial carbon SKT-4B, activated fibrous carbon AFC <<Dnepr>>, metall
ized carbon BKTM). For three identical adsorption pumps with different
adsorbents the speed of He-4 pumping is measured as a function of pre
ssure and degree of the pump filling. The operation of these three pum
ps is investigated under conditions close to those of their use in low
-temperature cryostats for He-3 pumping.