Correlation of photon beam motion with vacuum chamber cooling on the NSLS x-ray ring

Conference · Tue Dec 31 04:00:00 EST 1991

OSTI ID:10114634

Johnson, E D; Fauchet, A M; Zhang, Xiaohao

The NSLS X-ray ring exhibits a direct correlation between photon beam motion, and distortion of the ring vacuum chamber induced by fluctuations in the cooling system. We have made long term measurements of photon beam vertical position, accelerator vacuum chamber motion, process water temperatures, and angular motions of the magnets around one superperiod of the NSLS x-ray ring. Short term transients in water temperature cause deflection of the ring vacuum chamber which have in turn been shown to induce very small angular rotations of the magnets, on the order of 10 micro-radians. A larger and more difficult to correct effect is the drift in beam position over the course of a fill. This problem has been shown to be related to the thermal gradients that develop across the vacuum chamber which, as a consequence of the configuration of the chamber cooling, depend upon stored current. Orbit simulations based upon the measured rotations are in agreement with the observed beam motions, and reveal that certain patterns of correlated motions of the magnets can produce much larger errors than random motion or concerted motion of all the magnets. During the course of these measurements global orbit feedback was installed, and found to significantly reduce the orbit errors which could not be corrected at their source.

• Research Organization: Brookhaven National Lab., Upton, NY (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 10114634
• Report Number(s): BNL--46838; CONF-910730--29; CONF-9110146--6; ON: DE92005383
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430303
COMPUTERIZED SIMULATION
COOLING SYSTEMS
CORRELATIONS
EXPERIMENTAL FACILITIES AND EQUIPMENT
MOTION
NSLS
PHOTON BEAMS
PRESSURE VESSELS
SYNCHROTRON RADIATION SOURCES