Improvement of RHIC warm beam vacuum for high intensity operation

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.