Accelerator Update

Prepping for a New X9 Insertion Device and Beamline

February 1, 2008

Jim Murphy
Accelerator & Operations Division
jbm@bnl.gov

Archives:
February 2008
November 2007
June 2007

The recently completed fall/winter 2007 shutdown was chock full of both short- and long-term accelerator improvements. The central theme of the shutdown was the preparation of the X-ray ring for future installation of the new X9 insertion device, front end, and beamline. To that end, a new vacuum valve had to be located between two of the radio frequency (RF) cavities and a new active interlock pick-up electrode (PUE) had to be installed just upstream of these cavities.

This intricate pair of tasks necessitated breaking vacuum in the ring and venting one and a half (of the eight) superperiods of the X-ray ring up to atmospheric pressure using dry nitrogen. The mechanical design, engineering, and technical staff led this effort and even concluded a few days early, which provided extra commissioning time. The vacuum break required a multi-day bake-out of the effected vacuum chambers prior to commissioning. The electrical engineering and technical staff implemented a new web-based monitoring system to track the temperature (thermocouples) and thermal expansion (LVDTs) of the chamber during the bake-out. The tracking system provided instantaneous updates and alarm functions to protect the three delicate ceramic sections of vacuum chamber that were part of the bake-out.

The construction of the X9 undulator has made excellent progress. Presently, it is undergoing magnetic measurement and shimming to optimize the quality of the magnetic field. The close collaboration between the mechanical and magnet lab teams has produced an insertion device of very high quality, requiring a minimal amount of field correction. The monitoring system developed for the fall shutdown will be used during the bake-out of the insertion device. Installation of the undulator should proceed in a straightforward manner in May 2008 as the device simply replaces a vacuum chamber spool piece between two vacuum valves.

The booster ring has seven ion pumps to provide the necessary vacuum for the ring. Two of the ion pumps were replaced with new pumps during the fall shutdown to provide good vacuum for the lifetime of booster ring. Additional pumps will be upgraded in future shutdowns.

A multifaceted shutdown such as the one just completed requires extensive work planning to ensure all tasks can be completed safely and in a timely fashion. Our work control coordinators and planner worked together with the ESH&Q staff to produce a safe and successful shutdown.

The NSLS Survey Team discussing alignment of the X-ray ring.

Shutdown and maintenance periods provide the opportunity to conduct preventive maintenance (PM) on the multitude of hardware systems throughout the NSLS complex. Many systems did receive their regularly scheduled PM and a lot of progress was made on the Electrical Equipment Inspection program.

The linac, booster, and VUV machines were commissioned with relative ease by the operations and accelerator physics teams and the machines came back online for user operations as scheduled. The extensive work on the X-ray ring during the shutdown, in particular the need to vent a significant fraction of the ring to atmospheric pressure and the removal/reinstallation of the injection kicker magnets, made the X-ray ring commissioning a more challenging task. The guiding principle in the commissioning was to provide the maximum amount of the beam to the user community and to keep them well informed of ongoing developments. We thank the NSLS staff and the user community for helping to position us to launch the new capabilities that the X9 insertion device and beamline will bring in the near future. You can read more about this new and exciting beamline in this issue of eNews.

On another note, I recently highlighted the high-brightness electron beam and free electron laser R&D program at the NSLS Source Development Lab in the 432nd Brookhaven Lecture entitled "At the Cutting Edge of Bright Beams: The NSLS Source Development Lab." If you missed it, you can watch the lecture here.