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Even Electrons Need a Vacation

Starting today, SPEAR3 will be shut down for annual maintenance and upgrades. The shutdown, which began this morning at 6:00 a.m. and will last until early October, gives engineers an opportunity to perform maintenance and equipment upgrades.

This year most many of the accelerator upgrades are geared toward implementing top-off injection in SPEAR. Among these upgrades is a new ejection septum chamber, a device located at the point where electrons leave the booster ring to be injected into the SPEAR3 main storage ring. With the present chamber, the beam spreads out slightly as it passes through a special vacuum-tight window, reducing the efficiency of injecting electrons into SPEAR. The new septum chamber will eliminate that problem and give operators a tighter beam out of the booster.

Also slated for upgrade is the 9-meter-long linear accelerator that creates the initial pulses that are boosted and injected into SPEAR3. The SPEAR3 linac, which is a miniature version of the 2-mile linac at SLAC, is receiving a second klystron that will roughly double the energy of electrons entering the booster. This extra energy should improve the capture of electrons into the booster and make top off injection into SPEAR more efficient.

Preparations for the new beamline 12 will also continue during the shutdown with the installation of a new in-vacuum undulator, the first of its kind at SLAC. This undulator will give users a much higher degree of control over the x-rays produced. Beamline 12 experimental hardware will also be installed in the new hutches that were built this summer. The new beamline is scheduled to be commissioned in 2007.

—Brad Plummer
    SLAC Today, August 7, 2006

Above photo: Preparations for SSRL's new beamline 12 will continue during the shutdown. (Click on image for larger version.)