AVS 50th International Symposium
    Vacuum Technology Wednesday Sessions
       Session VT-WeA

Paper VT-WeA6
RHIC Pressure Rise with High Intensity Beam*

Wednesday, November 5, 2003, 3:40 pm, Room 323

Session: Outgassing and Large Vacuum Systems
Presenter: H.C. Hseuh, Brookhaven National Laboratory
Authors: P. He, Brookhaven National Laboratory
H.C. Hseuh, Brookhaven National Laboratory
L.A. Smart, Brookhaven National Laboratory
D. Weiss, Brookhaven National Laboratory
S.Y. Zhang, Brookhaven National Laboratory
Correspondent: Click to Email
RHIC is a superconducting heavy ion collider with two rings of 3.8 km circumference designed for nuclear physics research. With increasing ion beam intensity during recent RHIC operations, pressure rises of several decades within a few seconds were observed at a few room temperature vacuum sections. There are two distinct types of pressure rises, one occurs at injection and the other during acceleration. The first type has been associated with electron multi-pacting, electron stimulated desorption and ion desorption. The second type is coupled with beam halo scraping and desorption, with desorption rates of up to 10e+7 molecules per incident ion. Improvements to the RHIC vacuum systems have been evaluated, and some implemented, including extensive in-situ bakes, additional UHV pumping with lumped pumps and NEG coating, electron detectors and beam tube solenoids. The effectiveness of these measures in reducing the beam induced pressure bumps and increasing the vacuum system reliability are discussed and summarized. *Work performed under Contract Number DE-AC02-98CH10886 with the auspicious of the U.S. Department of Energy.