To the problem of continued cryosorption pumping out

Shown is efficiency of continuous cryoadsorption pumping out in forevacuum as well as in high vacuum pressure range. Expressed are considerations about possibility of helium pumping out even using fluid nitrogen as a cooling agent. For a concrete system of parameters, characterizing pump operation (adsorption isotherms, initial pressure, specific leakage, duration of cooling cycle, etc) calculated are dependences of air pressure and partial helium pressure in the pumping out volume on the pump operation time (number of cooling cycles). It is shown, that by selecting duration of the cooling cycle at reasonable value of specific leakage one can provide, in principle, limiting pressure below 10-8-10-9 mm Hg using fluid nitrogen