Jefferson Lab Weekly Briefs October 26, 2011
Jefferson Lab Weekly Briefs
October 26, 2011
12 GeV Upgrade
At the request of the Office of Nuclear Physics, Daniel Lehman, Director of the Office of Project Assessment in DOE's Office of Science, convened a team of 24 experts plus 10 observers in an Independent Project Review of the 12 GeV CEBAF Upgrade Project held Oct. 18-20 at JLab. The purpose of the review was to assess progress in all aspects of the project. The review committee commented on the excellent progress made over the last year, with strong support from the lab in all areas. Twelve recommendations were provided to guide activities in the coming months.
Refinement of the low-level radiofrequency control system continues. Checkout of the second 12 GeV cryomodule, C100-2, is almost complete. The third 12 GeV cryomodule has been completed and moved to the Cryomodule Test Facility. Three more are being assembled. JLab personnel witnessed testing of the first-article box supply at the vendor’s facility. Assembly of the third new RF zone is nearly complete.
In Hall C, the High-Resolution Kaon Spectrometer has been fully disassembled and relocated to the Experimental Staging Building. Hall C staff, JLab staff and the Q-weak collaboration are engaged in final preparations for the resumption of the Q-weak experiment in November. The Moller polarimeter has been repaired and the beamline in the area of the polarimeter is under vacuum. The Q-weak liquid hydrogen target underwent a successful cool-down test and has been surveyed into position. New beam current monitors have been installed on the beamline. These monitors, when coupled with the new BCM electronics, will minimize the contribution of current measurement noise to the error on the measurement of Q-weak. A sieve slit has been installed in region I of the Q-weak setup in order to enhance tracking mode measurements.
Radiofrequency commissioning of SL25 continued. The dipole power supply for the spectrometer magnet at 0L07 was replaced. Radiation measurements at the northeast stub gate were performed with beam in the 0L07 spectrometer dump and later with north linac RF on; radiation levels remained at background for both instances. During the evening shifts, the injector was set up for upcoming low-energy beam breakup studies. Afterward, work on the injector laser table was performed by Q-weak personnel; later in the week, Q-weak performed studies with beam in the injector. The area in the northeast spreader region damaged from the overheated magnets was cleaned up. The damaged magnets were removed for later replacement with spares. Beam instrumentation and beam loss sensors in the area were checked out, with some replaced purely as a precaution. Operations staff began turning on the north and south linac RF cavities to verify operation.
A new theory paper explores the sensitivity of W and Z boson production in hadronic collisions to uncertainties in parton distribution functions (PDFs) at large momentum fraction x, showing increasing effects at high boson rapidities, particularly for the d quark. The effects of PDF uncertainties on heavy W' and Z' bosons beyond the Standard Model become progressively more important for larger boson masses, in both proton-proton collisions at the LHC and in proton-antiproton scattering at the Tevatron. The PDF uncertainties at large x will be reduced with new data from deep-inelastic scattering measurements at JLab following the 12 GeV Upgrade.
The Electrical Support Groups have been busy performing checkout of magnet, RF and Instrumentation & Controls systems in preparation for resuming accelerator operation. Initial power up and interlock checks are performed prior to full operational restoration. Problems have been encountered with RF loads and magnet ground isolation issues that have required significant effort to rectify. Diagnostic and vacuum restoration activities have gone better, with most equipment being restored without major problems. Work on the 12 GeV RF system commissioning and installation has continued in parallel with the recovery work. Two of the new RF systems are being prepared for beam testing during start up and hopefully will run in support of the upcoming Physics program. Gaining operational experience now with the new RF systems will greatly enhance the 12 GeV accelerator start up following the next long shutdown.
Environment, Safety, Health and Quality
Halloween Safety Tips
Additional Halloween safety tips can be found online at Wavy.com, the Consumer Product Safety Commission website and the Halloween Safety website. For non-trick-or-treating Halloween celebration ideas, see the Travel Virginia website and the local events calendar.
Computing and Networking Infrastructure
Major Systems Outage on Friday, Dec. 23
JLab Beam Kickoff and Tailgate Party
Annual E-Commerce Small Business Vendor Show
Tracking Thomas at JLab
Congratulations this week go to DeAnn Maddox, Karen Bartek, Michael Wilson, Mike Martin, Rochard Jacobsen and Narciso Gomez, who were the first to correctly identify the Oct. 19 location. Honorable mentions go to Brita Hampton, Sam Holben, Greg Adams, Dick Owen, Jason Willoughby, Doug Higinbotham, Michael Haddox-Schatz, Cindy Eller, Lisa Surles-Law, Guy Wilson, Jim Follkie, Harry Fanning and Dena Polyhronakis. Check out the Tracking Thomas webpage for a better view of his last location and this week's new mystery photo.
JLab Calendar of Events
Nov. 1: Science Series public lecture