Pressure measurements in the AGS Booster ultra-high vacuum system

An average pressure of mid 10-11 torr has been achieved and maintained in the AGS Booster ring vacuum system during its first year of operation. This ultra-high vacuum system is monitored through remote controlled Bayard-Alpert Gages (BAGs). The characteristics of the pressure measurements with BAGs over the long cable lengths (up to 200m) and under various accelerator operating conditions will be described. Two types of noise in the pressure readouts have been identified; the electromagnetic interference (EMI) associated with the acceleration cycles of the Booster and the environment noise associated with the solar heating of the collector cables. The magnitude of the noise pickup depends on the routing of the collector cables and reaches the equivalent pressure of low 10-9 torr. (author)