The Relativistic Heavy Ion Collider (RHIC) Project is a nuclear physics research accelerator at Brookhaven National Laboratory (BNL) with beam circulation scheduled for May 1999. To achieve the necessary beam lifetime, the vacuum in the two concentric rings must be constantly monitored to isolate problem vacuum regions. One function of the RHIC vacuum instrumentation and control (I&C) system is to operate sector valves with inputs from several hundred gauges and pumps distributed around the 3.8 km circumference of the accelerator rings. The architecture and implementation of the RHIC vacuum I&C system from the pumps and gauges to the remote user interfaces are described.

With increasing ion beam intensity during recent RHIC operations, pressure rises of several decades were observed at a few warm vacuum sections. Improvement of the warm sections has been carried out in last year's shutdown. Extensive in-situ bakes, additional UHV pumping, electron detectors and beam tube solenoids have been implemented. Vacuum monitoring and interlock were enhanced to reduce premature beam aborts. The effectiveness of these measures in reducing the beam induced pressure bumps and in increasing the vacuum system reliability are discussed and summarized.