Jefferson Lab Weekly Briefs
April 13, 2011
12 GeV Upgrade
With only five weeks until the start of the summer 2011 shutdown, the 12 GeV project installation activities have been integrated into the labwide schedule. Additional transportation and material handling equipment has been secured to support the effort. Existing trailers have been outfitted to support additional contract employees, and storage/staging locations are in place. The project team is finalizing work-planning documents in preparation for the down, as well as handover documents to Accelerator Operations and training for operators and technicians.
Hall A ran the short-range correlation experiment this week. The running was very efficient and the data is looking good. Accelerator availability has been excellent.
Q-weak has continued production data taking on the high-power hydrogen target with currents up to 165 microamps in Hall C. The data taking is interspersed with regular measurements of beam polarization and background asymmetry measurements on aluminum.
Last week, the CEBAF accelerator delivered beam to Halls A and C with 87.6 percent beam availability. Hall B has been offline for installation of HDice. During Tuesday’s beam studies, the Wien was flipped from right to left, and some optics data were collected for improvement of beam quality. On Thursday, the gun2 photocathode was heated and reactivated, resulting in 1.4 percent quantum efficiency of the cathode. Maintenance on the Arc2 dipole power supply was performed in parallel with the cathode activation. Performance over the weekend was robust with about 13 Coulombs/day delivered for physics research. Vigilant maintenance of the injector orbit over the past few weeks by Operations staff has contributed to the high availability. Identifying the source of the observed subtle injector orbit shifts is presently ongoing.
After getting the infrared FEL back up and lasing reliably from a seven-month ultraviolet hiatus, the FEL team spent the week setting up and starting two sets of IR optics measurements for Joint Technology Office/Office of Naval Research programs. The team also performed some double resonance terahertz experiments for the University of Southampton.
Computational and Theoretical Physics
This week, JLab is hosting the XIX International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS 2011), the premier annual meeting of the parton structure community. The meeting has approximately 350 experimental and theoretical nuclear and high-energy physicists from around the world, and is for practical reasons being held at the nearby Marriott City Center. Topics reviewed at the conference include structure functions, QCD, spin physics, electroweak physics and physics beyond the Standard Model, as well as the first results on parton distributions from the Large Hadron Collider.
The machine shop is presently drilling and taping the upstream and downstream ends of 37 four-meter XP-style magnets to accommodate the addition of end shims. The end shims are being laser cut by an outside source.
The shop is also continuing efforts in the manufacture of the deflecting mode Crab Cavity for Argonne National Lab. The prototype cavity has been trimmed for tuning, and the weld preps have been completed. The "Y"-shaped waveguide has been machined and is ready for welding. Since Feb. 28, the shop has processed 215 job requests.
The electric systems group (EES) reports that two more klystrons were received, as well. In addition, the second 12 GeV klystron cathode power supply has been delivered and placed in zone SL25 in the south linac along with klystron pedestals. With klystron pedestals and CPS's installed in zones SL24 and SL25, the 12 GeV radiofrequency systems are becoming a reality.
Environment, Safety, Health and Quality
Practice Window Safety to Prevent Falls
Computing and Networking Infrastructure
CNI Maintenance Day Tuesday, April 19
Get in on Home Energy Savings With 'Next Step' Program
Education Seeks Projects, Mentors for Summer High School Interns
Agilent Tour Bus Onsite
Tracking Thomas at JLab
Congratulations to David Fazenbaker and Jason Willoughby, who were the first people to correctly identify the April 6 location. Honorable mentions go out to Simon Taylor, George Biallas, Mike Koch, Rebecca Yasky and Josh Foyles. 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
April 11-15: DIS2011