Jefferson Lab Weekly Briefs
September 28, 2011
12 GeV Upgrade
Civil construction had two highlights last week. First, on the Hall D construction site, the last exterior concrete pour for the tunnel connection was completed on Friday morning, just ahead of the rain. The construction contractor has revised the sequence of activities to allow interior and exterior work to be performed in parallel to recover some weather-related schedule delays. Second, the upgraded low conductivity water systems in the South Access building for the east arc magnets and the south linac radiofrequency zones were commissioned on Thursday. The punchlist items are being addressed and the systems are scheduled for turnover to operations this week. At the North Access building, water is being circulated through the upgraded LCW systems. The west arc magnet and the north linac RF zones will be brought online starting this week, with commissioning to follow.
The Polarized Electrons for Polarized Positrons experiment alignment has been performed and fabrication of the forms around the stand bases has been completed; staffers continued pulling cables to the new rack and performing detector tests. The old 500 KeV Mott line has been decommissioned, and a new Mott ladder was installed and tested. Lead and poly shielding bricks around the 0L07 dump that were previously removed have been re-stacked, and the repaired 0L07 magnet power supply was returned to service. Additional concrete block shield walls were installed behind the dump for injector beam testing next month. Arc 10 survey and alignment was completed. Installation of interlock cables for 2L22 and 2L23 was completed. During the day, 2L24 low-level RF testing continues with signal checking, control system response tests and software corrections; at night, 2L24 cable calibration and correction continued, along with loop gains and overall system optimizations. On 2L25, the prototype solenoid power supply cable was replaced and klystrons 2, 6, 7 and 8 were retested. Work continued on the Hall D communication trench; the main trench box was installed, along with the concrete block covers, and work on the junction box began.
The FEL team determined that the gun cathode was unusable due to lack of quantum efficiency, despite several tries at cesiation; the solution is to open up and replace the cathode with a new one. At the same time, the team will address discharge issues that have limited the operating voltage. The new ultraviolet wiggler was set in the pit, wired up and is being surveyed into position. Lastly, the team is performing a warmup to room temperature of the FL03 cryomodule to drive off condensed gas, which limited the achievable gradient in at least one of the cavities.
Center for Theoretical and Computational Physics
Quark confinement is believed to control the structure and dynamics of hadrons. This, in turn, depends on the long-range behavior of the gluons (and ghosts) that bind quarks together. A new Theory Center paper discusses the limitations of present strong coupling QCD calculations in determining this long-range behavior and how a better understanding of the ghost-gluon interactions is required to make predictions robust.
The Machine Shop is presently manufacturing:
The shop has processed 171 job requests since Aug. 15.
JLab Calendar of Events
Oct. 3: Safety Shoe vendor onsite
Environment, Safety, Health and Quality
According to the National Safety Council, there is an injury on the job every nine seconds, and there is a death on the job every 112 minutes. It is vital to the safety and wellbeing of ourselves and our co-workers that we at JLab not contribute to this statistic.
JLab's Integrated Safety Management System features practices and policies designed to keep us and our co-workers safe, and it should always be used in the planning and execution of work. ISMS includes steps for:
For more information about JLab's ISMS and impementing the procedure in your work, see ES&H Manual 3210 Appendix T1.
Partial Closure of CEBAF Center Circle, Sept. 29-30
Test Lab Area Access Restricted During Exterior Painting
Blood Drive Set for Next Week
Flu Vaccinations Available
Robotics Team Needs a Coach
Tracking Thomas at JLab
Congratulations this week go to Dave Fazenbaker, Jason Willoughby, Doug Higinbotham and Narciso Gomez, who were the first to correctly identify the Sept. 21 location. Honorable mentions go to Tonya Evans, Zhe Vick Chen, Michelle Shinn, David Anthony, Andy Kowalski, Stephen Smith, Dick Owen and Cindy Eller. Check out the Tracking Thomas webpage for a better view of his last location and this week's new mystery photo.