July 1, 2005  


New Milestone for SPEAR3

By Francoise Chanut

SPEAR3, SSRL’s recently upgraded synchrotron radiation source at SLAC, reached 500 milliamps (mA) for the first time on June 20, and again on June 21.

“We were able to go to the design current without any problem related to instability in the electron beam,” Piero Pianetta (SSRL) said.

This figure shows the duration of the high-current run.
(Image courtesy of SSRL)

The milestone was achieved as part of a series of tests designed to bring SPEAR3 to its full design performance. SPEAR3 has been running at 100 mA for the past year and a half but will ultimately operate at 500 mA routinely, generating brighter X-ray beams that will make new experiments possible. “It was a major step, the fruition of almost nine years of hard work and a lot of meetings!” Bob Hettel (SSRL) said. The SPEAR3 upgrade was first discussed in 1996 and made possible by funding from DOE and NIH, he said.

Hettel and members of a multi-disciplinary team tested SPEAR3 on June 20 and 21. They gradually increased the electron beam intensity from 100 to 500 mA over the course of four hours, carefully checking for potential damage to the equipment at every step. They did not encounter any problems, Hettel said. The electron beam did show some instability at first, but the problem was easily corrected the second night with the help of engineers from the CPE and Klystron/Microwave groups, he said.

“This achievement is a demonstration of the tremendous energy and teamwork of the SSRL SPEAR3 accelerator group working closely with other key staff at SLAC,” said Photon Science Director Keith Hodgson. “Achieving maximum design performance so smoothly reflects the quality of the accelerator and control system and reinforces the value of the significant investment by DOE and NIH in building the new machine.”

A test run of SPEAR3 at 200 mA a year ago had gone similarly smoothly, but further preparation was needed to meet the requirements of a DOE-mandated Accelerator Readiness Review before the 500 mA test.

The next big step now is to complete the upgrade of the synchrotron radiation beam lines. The first beam lines ready for 500-mA operation will be available to users in 2006, Hettel said.

“Operating at maximum performance levels, SPEAR3 will provide SSRL’s users with capabilities equivalent to the best in its class in the world, and enable scientific discovery in areas like study of nano-structured materials and microcrystal diffraction which will take full advantage of the high brightness of SPEAR3,” Hodgson said.


The Stanford Linear Accelerator Center is managed by Stanford University for the US Department of Energy

Last update Friday July 01, 2005 by Topher White