Accelerator Update
Winter Shutdown, Klystron Backup Plan Completed Successfully
April 2, 2009
Jim Murphy
Accelerator & Operations Division
jbm@bnl.gov
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The winter 2008 shutdown that began in the second week of December was successfully completed and the accelerator complex was returned to operation promptly in the New Year. Delaying the start of the shutdown until after the Thanksgiving holiday provided about two weeks of additional operations time to the user community. Two new extraction kicker magnet power supplies were installed in the Booster Ring to improve extraction to the VUV Ring. A new pulsed trim magnet was added to the extraction line from the booster to the X-Ray Ring to improve transport between the rings. Several new ion pumps were installed in the Booster Ring as part of a long-term preventive maintenance program. On the utilities front, a new control valve and control system was implemented on one of the air handler units to improve performance and modifications were made to the pump configuration of the low-pressure copper water system to improve flow characteristics. As always, a successful shutdown is the result of superb planning and excellent collaboration among the highly skilled technical and safety teams.
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During routine operations, the NSLS linac accelerates the electron beam to 120 MeV prior to injection into the Booster Ring. Three operating klystrons are required to achieve this energy. Since we had two klystrons fail within the last year, a backup plan was developed to enable injection into the Booster at 80 MeV using only two klystrons. Injection into the booster at 80 MeV has been successfully established by a team from the NSLS accelerator physics & electrical groups. Some RF windows will be added to the linac system to partition the vacuum system so that repairs could be done to either klystrons 2 or 3 with a minimum downtime; klystron 1 must be in operation at all times as it also powers the buncher cavity as well as klystrons 2 and 3.
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On the diagnostics front, improvements were made to the wall current monitors in the injection system and the Libera single-turn beam-position monitoring systems were implemented on both the VUV & X-Ray Rings. These enhancements will lead to better understanding of the injection process and improved injection efficiencies into the storage rings.
The new mini-gap undulator (MGU) was installed in the X9 straight section of the X-Ray Ring in August 2008. Since then the insertion device has been centered in the straight section, the active interlock system has been commissioned and the first light was observed in the experimental endstation in late February 2009. The work is advancing as a fruitful collaboration between all divisions of the NSLS. Commissioning of the beamline will progress toward operation at the full current of 300 mA in the ring, followed by experiments by the NSLS and Center for Functional Nanomaterials user communities.
Senior Project Engineer Peter Zuhoski has taken on an expanded leadership role in two key positions at the NSLS. As Deputy for Operations, Peter will assist Operations Section Head Emil Zitvogel in overseeing and advancing the operation of the entire accelerator complex. As Electrical Engineering Section Head, Peter will lead our team of electrical engineers and oversee the direction of our technical staff. Peter built his extensive technical expertise in power systems during his 28-year career at BNL. Please welcome and support Peter in his new roles.
Two new staff members have joined the Accelerator & Operations division recently: Christopher Sorrentino is an electronics technician in the RF & Power Systems group and Dr. Yoshiteru Hidaka is a physicist in the Accelerator Physics group.
Plans for the spring 2009 shutdown are nearly completed and the next segment of the long-term schedule is available online. The emphasis of the shutdown will be to address a potential vacuum leak in the neighborhood of the X27 front end. The leak was identified by the NSLS Vacuum group at the beginning of the winter shutdown in December 2008. The leak was sprayed with a sealant and successfully closed temporarily; the shutdown period will be used to replace the faulty equipment to secure the ring vacuum. The new parts were designed and fabricated by the NSLS Mechanical Group. Further down the road, in the winter 2009 shutdown, we anticipate doing some remedial vacuum work to address heating issues near the X7 front end. Water cooling bands have been added in several areas to reduce the elevated temperatures of the beam pipes. Also in December 2009, we are planning to undertake replacement of the deteriorated dunnage that supports the BAC cooling towers on the NSLS roof. The contract to build the new X17A experimental endstation is advancing through the contracts & procurement process.
Through the end of February 2009 the machine reliabilities for FY09 are 98.9% and 96.9%, respectively, for the VUV & X-Ray Rings. Thanks to all who make it possible!