Experimental tests performed in vacuo indicated that a chemical adsorption reaction can be used to facilitate the cryopumping of H with liquidN-cooled condensers. Cryopumping is accomplished by reacting H with O to form H2O, which will readily condense on a liquid-N-cooled surface. The reaction in vacuo was performed on a solid catalyst, which consisted of a bed of Pd-coated alumina pellets. Cryopumping was observed at pressures as low as about 0.4 micron of mercury. A laboratory cryopump consisting of 5.8 lb of catalyst and a liquid-N-cooled condenser achieved a pumping speed of about 570 l/sec at 1.0 micron of Hg. A laboratory model of a cryopump which could be used in an electric rocket test facility was studied. The experimental data obtained were used to estimate the size of the catalyst bed necessary to test a 50-kw electric thermal rocket with an H propellant flow rate of 0.00063 kg/sec (a pumping speed of 580,000 l/sec at an operating pressure of 10 microns of Hg. (Author).

This book covers the physical theory, practical techniques, and applications of cryopumping--the production of a vacuum through the use of low temperatures. The importance of this technique has increased greatly in recent years due to the proliferation of new uses and the demand in many vacuum procedures for ultraclean gas atmospheres, low final pressures, and high specific pumping speeds. The author reviews recent developments that have resulted in safer pumps that allow full automation and that are superior to conventional pumps in installation and operation costs.