chapter  40
Vacuum Measurement
Pages 22

To make measurements in the vacuum region, one must possess knowledge of the expected pressure range required by the processes taking place in the vacuum chamber as well as the accuracy and/or repeatability of the measurement required for the process. Typical vacuum systems require that many orders of magnitude of pressures must be measured. In many applications, the pressure range may be eight orders of magnitude or from atmospheric 1.01 × 105 Pa (760 torr) to 1 × 10−3 Pa (7.5 × 10−6 torr).