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.

This third updated and enlarged edition includes about 350 new papers added to the previous list of references. The contents have been revised and updated in the areas of: Thermonuclear pumping; Throughput; Transmission probability; Electronic circuit simulation; Sorption on charcoal; Desorption from porous materials; Desorption from stainless steel, A1 alloys (outgassing rates); Ion bombardment (glow discharge) cleaning; Clay - type pumps; Turbomolecular pumps-improvements; Cryosorption; NEG (Nonevaporable getter) linear pumps; Standards for measurement of pumping speed (Recommended practice, test domes); Spinning rotor gauges; Quartz friction gauges; Increase of sensitivity of thermocouple gauges; Lubrication in vacuum; Calibration of diffusion leaks; Improvements in leak detection. Besides its role in educational activities, the book will also serve as a handbook for those working in this field, or in fields connected to Vacuum Technology.Comments from the press on the second edition:"A valuable reference work for undergraduate libraries...well organized and clearly written and strikes an appropriate balance between completeness and attention to fundamentals. The index and references are unusually complete. Recommended." (Choice) "Roth's new book contains a comprehensive collection of information on rarefied-gas flow, physical and chemical phenomena associated with vacuum technology, the production and measurement of high vacuum and sealing and leak-detection techniques. One finds a wealth of equations, numerical examples, tables, graphs and monographs. The book is more a handbook than a source book of latest developments. It is suitable for teaching, but the wealth of organized data should also make the book highly useful to engineers..." (Physics Today)