The upcoming long-term operating schedule has been published and users will note that it includes an extended shutdown period (October 26, 2015-January 13, 2016) for the ALS. The lengthy shutdown is in part because it spans the Thanksgiving and Holiday shutdown periods, as well as being indicative of the amount of time required to implement major upgrades. The main project for this shutdown is the Storage Ring Radio Frequency (SRRF) Upgrade. This is the final phase of this many-year effort to provide more RF power that will be required for the use of additional insertion devices, and to create a robust back-up system. We have already replaced our long-lived klystron, the RF high-voltage power supply, and the high-voltage RF switch in prior shutdowns. While the ALS reliably operated on this new equipment, a second klystron was also installed. This last phase installs a “switch matrix” RF wave guide, which in its nominal state will provide each ALS storage ring RF cavity with RF from a single klystron. In the event of a klystron failure in the future, we will be able to redirect RF from either klystron to either cavity in the matter of hours rather than the many days it would take to swap out and commission a spare klystron.
The other major activity planned for this shutdown is installing the very first non-evaporable-getter(NEG)-coated vacuum chamber in the ALS. This is new technology for the ALS, and is very exciting since it will enable the small gap insertion device required to meet the carbon edge on the new COSMIC beamline in sector 7. While there are many other accelerator activities planned, these are the major shutdown projects.
In order to maintain and expand ALS capabilities for users, the last couple of years have been an extensive period of renewal and upgrades including Top Off, the Sextupole Upgrade (low-emittance lattice), the RF Upgrade, the Instrumentation and Controls Upgrade, and the chicaning of sector 7 for the MAESTRO and COSMIC beamlines. The next couple of major shutdowns will focus on changes required to create the space needed in sector 2 of the accelerator for the Howard Hughes Medical Institute funded Gemini insertion device and the installation of the Gemini beamline front-end.
Beamline work for this upcoming shutdown has not yet been detailed, but work requests are already being submitted. Staff and users are asked to contact Steve Rossi as soon as possible with work requests planned for the shutdown.