Accelerator Update

Spring Shutdown Completed Successfully, Ahead of Time

June 6, 2008

Jim Murphy
Accelerator & Operations Division
jbm@bnl.gov

Archives:
June 2008
February 2008
November 2007
June 2007

The spring 2008 shutdown has just been completed with aplomb due to the excellent teamwork of the staff of the Accelerator & Operations, Environmental, Safety, Health & Quality, and the Experimental Systems divisions. After a month of extensive work involving installations, upgrades, and maintenance, the entire accelerator complex was brought back online without a stitch of downtime.

Highlights of the spring 2008 shutdown included:

• replacement of klystron 1 in the linac
• improvements to the booster vacuum system
• connection of the X9 front-end to the X-Ray Ring vacuum chamber
• continuation of tasks to ensure electrical compliance (Electrical Equipment Inspection)
• a long list of preventative maintenance items
• improvements to the pulsed magnet (kicker) system in the Booster Ring

As we came to the end of the operations run prior to the spring shutdown, it was clear that we were struggling with a failing klystron. The RF & Power Systems and Vacuum groups began work on May 5 and one of two spare klystrons was in place and vacuum baked within several days. Completion of the task had to wait until the linac/booster could be secured at the end of the maintenance period. Conditioning of the klystron and the linac went quickly and successfully.

The development of the new X9 beamline took an important step forward when the Mechanical Group connected the X9 front end to the X-Ray Ring; the X9 water-cooled mask, the water-cooled aperture, the fast valve, and vacuum valve were baked out and connected to the X-Ray Ring during the spring 2008 shutdown. A bake-out of X-Ray super-period two followed to ensure good X-Ray Ring vacuum. The X-Z table assembly, which includes the X-Z frames and adjusters, a water-cooled collimator, and a differential ion pump, were fabricated and delivered to NSLS just before the spring 2008 shutdown, but they were not installed largely due to a vacuum leak in the differential ion pump. These components were each bench-assembled in May, and will be installed during the August-September 2008 shutdown.

Pete DeToll (left) and Xi Yang working in the Booster during the shutdown.

Fabrication, assembly and testing of the new X9 mini-gap undulator (MGU) continued. Installation of the MGU is planned for the summer 2008 shutdown. The repair of a vacuum leak and correcting an out-of-spec phase error due to excessive magnetic array pitch are presently being addressed.

A faulty booster ion pump and a leaky linac-booster vacuum isolation valve in the injection/extraction area were replaced. These tasks required coordination with masons to remove an estimated 300 lead and concrete shielding blocks covering this area of the booster as well as removal of three kicker drivers. Thanks to the careful work of the BNL mason crew as well as the NSLS Vacuum and Power Systems Groups, everything went back together safely and successfully. The booster commissioned without a hitch on May 21 and the VUV Ring was filled that same day, two days ahead of schedule. A vacuum leak in another booster ion pump was identified during this maintenance period as well. Plans have been made to replace this pump during the upcoming August-September shutdown.

Each NSLS group has a list of periodic preventative maintenance items that need to be done in order to minimize downtime. This work is completed with little visibility, but is critical for reliable operations. Careful inspection of the RF Systems revealed several small problems that, if left alone, may have resulted in machine downtime.

When the NSLS facility was analyzed for arc flash hazards one year ago, a list of 18 electrical panels was compiled that were not rated to handle the short circuit current that the upstream device was capable of supplying. The last of the failed panels was remediated during the spring shutdown. This task required the coordination with technicians from Square D (a brand of Schneider Electric), who accomplished the task in order to maintain the manufacturer’s certifications. This work involved adding buss bar supports to the motor control center located in the center X-Ray service rack area. Kudos to the Electrical Distribution Group for safely retiring the last key arc flash hazard.

Several cooling water system preventative maintenance projects were also undertaken by the NSLS Utilities Group in the spring shutdown. Programming and software upgrades to the APACS software system were completed. This system is used for remote monitoring and control of the NSLS cooling water systems. Resistance Temperature Device (RTD) sensors were added to monitor the temperature of utilities cooling water pumps. A water leak was repaired in the Booster Ring and a vent was installed. Proteus and air solenoid preventative maintenance was performed. The Trane heat exchanger isolation valves for the Aluminum & Low Pressure Copper water systems were replaced. The EVP and COND Trane chillers were cleaned. This was a fairly large effort that could only be undertaken during an extended maintenance period. Several other important preventative maintenance items were also completed.

The Electrical Equipment Inspection program is continuing at a strong pace. This is an often-tedious task that has been undertaken by members of the Accelerator & Operations staff. They have done an excellent job and have set us on a path to meet the DOE deadline of having all high-hazard equipment inspected by the end of June 2008.

Electrical Engineering and the RF & Power Systems Group have made great progress on the development of a new kicker driver that will replace four aging kicker drivers currently in service in the booster ring. The linac-to-booster kicker (LBISH) and one X-Ray extraction kicker (BXESH1) are scheduled to be replaced during the upcoming August-September shutdown. The new design uses updated components and its layout, which uses modular sections, provides a vast improvement to serviceability compared to the current kicker drivers. This improvement will translate to a reduction in downtime since components can be changed out very quickly.

A Labview program has been designed and commissioned that displays and stores all the kicker pulse waveforms. This program will aid us in troubleshooting kicker failures and will help us to quickly return to operations following shutdown and maintenance periods. Waveforms corresponding to normal operations will be stored prior to machine shutdown and will be recalled and compared to live waveforms as we work to restore injection into the main rings from the injection system.

We owe many thanks to our staff for their dedication and service. This shutdown was completed ahead of schedule and most importantly, safely.