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From the Accelerator Directorate: Long Maintenance Down Time for the LCLS

(Photo - John Seeman)  (Photo - Dale Knutson)
John Seeman (left) and Dale Knutson. (Photos courtesy John Seeman and by Brad Plummer, respectively.)

Why has Linac Coherent Light Source been down so long? After significant planning, a scheduled 3-month down time began in December, to allow a key maintenance period for the LCLS linac. In this accelerator down time, SLAC's Accelerator, LCLS and Operations Directorates plan to do annual linac maintenance, some accelerator upgrades, and to complete those parts of the ongoing LCLS Construction Project that affect linac operations.

The LCLS shutdown started December 19, 2009, and will end with first beam from the LCLS injector returning at the end of March 2010. The planning for this long down time started about nine months ago. The overall scope was planned with the relevant support groups during the summer months. Then in September, we began the process of identifying in detail the needed jobs, specifying the shop support that was needed and determining the duration of each task. The accelerator technical area managers collected, organized, and have been releasing this work based on the agreed on schedule. Safety reviews and Work Planning and Control processes for each of these tasks have been carried out to make sure all aspects of the work have been identified and any safety or resource conflicts mitigated.

(Photo - LCLS downtime work)
Luis Tijiboy and Randy Moreno from the Power Conversion Department run lines in the Near Experimental Hall. (Photo by Olga Kuchment.)

"We use Microsoft Project planning software to plan and track all the jobs that we wish to carry out during the shutdown," said Stuart Metcalfe of the Accelerator Directorate Technical Planning Group. "The area managers adjust work scheduling to fit in the time available, then shop loading is compared with actual shop availability." Every Thursday at 2 p.m. in the Main Control Room, all groups go over the work plan for each job to make sure all related issues have been resolved.

(Photo - LCLS downtime work)
Installation in the Far Experimental Hall, Hutch 4. (Photo by Olga Kuchment.)

The tasks being completed cover a broad spectrum of functions. The Personnel Protection System will be modified in the linac and also in the LCLS Front End Enclosure to support future new programs; this will be followed by a recertification of the entire PPS system. The electrical substation rebuild in linac Sector 20 (the K10 project) will be completed to improve linac reliability. A radiation shielding wall will be installed in Sector 20 on the linac housing. Electrical services will be given annual maintenance. The linac klystrons, modulators and power supplies will be upgraded and maintained to improve reliability. Protective electrical covers will be installed for the linac beam focusing quadrupole magnets. Some linac controls will be upgraded. Several LCLS quadrupoles in the Beam Switch Yard will be removed, magnetically measured and reinstalled. The connection of the LCLS Front End Enclosure beam lines to the LCLS X-Ray Transport Line leading to the Far Experimental Hall will be completed. This list names a few of the tasks detailed in the seventeen-page down time job list.

As of late January, the down time is going well, according to schedule and according to work plans and controls. The Thursday meetings will continue every week until the beam resumes. Barring any changes stemming from the recent power outage, we expect beam to start running again for LCLS accelerator tune-up just before April 1.

—John Seeman and Dale Knutson
  SLAC Today, January 29, 2010