Equipment for total and partial pressure measurements in the ISR ultra-high vacuum system

Over 500 low pressure gauges were needed for monitoring of total pressures in the ultra-high vacuum system of the CERN Intersecting Storage Rings for protons (ISR). For analysis of the gas composition 30 residual gas analysers were required. About 200 total pressure gauges of different types were included to provide detailed information on the pressures during the rough pumping process. The technical specifications for the different instruments are discussed. Some difficulties, which limited the performance at an early stage are treated. Results of the acceptance tests on instruments delivered to CERN are presented. Procedures for total and partial pressure measurements in the ISR are reviewed. The performance of the instruments after final installation is discussed. (7 refs)