Pressure measurement for the UNK-1 vacuum system

The required vacuum 10/sup -9/ Torr at the UNK-1 will be produced by 3900 ion pumps. For pressure measurement in the 10/sup -5/-10/sup -9/ Torr range the system based on continuous monitoring of all ion pumps currents is being developed as a part of vacuum instrumentation. To cover such a range current-to-frequency converters are used as current monitors. Their outputs pass to the acquisition electronics packaged into Eurocard style. Crates are distributed over 14 surface buildings. This presentation focuses on the measurement principle and the major electronics components.