February 4, 2005  


SPEAR Accelerator Restarts Operations

By Eduardo Guerra and Jeff Corbett

SSRL’s SPEAR3 facility has restarted operations after completing its restart validation process and receiving approval to resume operations by the SLAC Director in consultation with the DOE.

“The safe and smooth restart of SPEAR was possible due to the extraordinary effort by SSRL staff and the tremendous support SSRL received from the other SLAC divisions throughout this process and the efforts by all the staff to implement and follow safety protocols,” said SSRL Associate Director Keith Hodgson.

SSRL department heads developed a Facility Restart Plan over the winter break to present to Director Jonathan Dorfan of SLAC for formal approval to operate SPEAR3. A review team appointed by the SLAC Director carried out a validation process of the restart plan between January 3 and January 13. The validation team’s report was positive, and on January 14, Ray Orbach, Director of the DOE Office of Science, concurred with Dorfan’s recommendation that SSRL begin operations.

Following written authorization from Dorfan, the SSRL Accelerator Systems Department received permission from Hodgson to turn on SPEAR3 on January 18. The accelerator startup process proceeded smoothly. After commissioning the 100 MeV LINAC, transport line and 3 GeV booster synchrotron, 10mA was stored in SPEAR3 on January 23 at 6 pm.

Interlock and electronic calibration checks ensued and the circulating current was increased to the nominal operating value of 100mA. Measurements of electron beam position and storage ring optics indicated the beam conditions were precisely the same as for the previous phase of operation. At present, the photon beam line check-out procedures are underway and the vacuum chamber is processing at a record pace.

After completing the pre-start requirements identified during the validation review, Dorfan gave written approval on January 27 to start the process of bringing the beam lines back on line for the users. This began with the execution of the beam line authorization process in which Radiation Physics and SSRL staff ensure the proper placement of radiation shielding components. The first beam line was then certified and by Friday, four beam lines were opened for alignment and initial radiation surveys.

During the coming week to 10 days, the remainder of the beam lines will be opened and the detailed radiation surveys will be performed. It is expected that beam will become available to users on some beam lines or before February 7. Normal full beam line operations are expected within two weeks thereafter.

SPEAR3 and the B Factory have been shut down since October, when a serious electrical accident led Dorfan to order the immediate suspension of operations.

Since the accident, SLAC has been rigorously scrutinizing safety procedures and safeguards to ensure that the accelerator facilities will be operated at the highest levels of safety. Dorfan was determined that each major facility complete a specific safety validation review to satisfy him and the DOE that there was a safe path forward.

“The restart of SPEAR3 operations should not in any way divert our ongoing attention from the strongest commitment to safety,” Dorfan said. “Our long-held commitment is that operational expediency can never override safety.”



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

Last update Tuesday February 01, 2005 by Emily Ball