Jefferson Lab Weekly Briefs April 16, 2008
Jefferson Lab Weekly Briefs
April 16, 2008
12 GeV Upgrade
The source selection plan for the Hall D Complex construction contractor was approved on April 9, 2006. The subcontract will be awarded to the offeror that represents the best value to JSA/Jefferson Lab on the basis of capability and price. The evaluation of capability will be based on several criteria, including experience with similar projects; the environmental, safety and health (ES&H) program; and past performance.
Review comments from an internal design and safety review of the 100 percent design of the North and South Access utility upgrades have been consolidated; a meeting to discuss these findings is scheduled for April 22.
This reporting period encompasses a full week of beam delivery to all three halls. The accelerator delivered a total of 294 hours of beam. Significant problems encountered and overcome were a failure of the Arc 1 box magnet supply due to water damage and subsequent corrosion of internal connections, and a split in a vacuum valve poly air line caused the vacuum valve to close. At the present high energy, the RF is being stressed to its upper limit and much effort is being expended in maintaining its operability.
Free-Electron Laser (FEL)
The gun test stand (GTS) achieved full-charge operation this week and is producing beam for diagnostics. The FEL injector has not been so fortunate and has experienced a ceramic leak that FEL staff members have not been able to permanently fix in situ. Given the scheduled Central Helium Liquefier shutdown in June, staffers will disassemble and fix the gun and not run the FEL until next October.
A collaboration between Theory Center staff and researchers from the Tokyo University of Science has for the first time developed a chiral version of the quark-meson coupling model. The new model is based on the volume coupling version of the cloudy bag model, in which the effects of the pion cloud and gluon exchange are included self-consistently, arXiv:0803.4362 [nucl-th]. The model describes symmetric nuclear matter reasonably well and predicts a decrease of the axial coupling constant with increasing nuclear baryon density. This implies that the isoscalar, central nuclear force is weakened in medium- and heavy-mass nuclei.
TIAA-CREF Retirement Counseling
Location Change for Ultimate Frisbee at JLab
JLab Adopt-A-Spot Event Needs Volunteers
National Library Week is April 13 - 19
Environment, Safety, Health & Quality
With warmer weather starting, many of us are planning home repair and maintenance activities. To prevent falls when using all types of ladders, follow these National Safety Council basic rules in placing, ascending and descending ladders:
For additional ladder or elevated work platform information, see JLab ES&H Manual Chapter 6132, Ladders and Scaffolds.
DOE Center for Electrical Safety Excellence
Computing and Networking Infrastructure (CNI)
Attention JLab Wireless Network Users
JLab's Safety Numbers
210 Days since Last Recordable Accident (JLab record: 319)
JLab Calendar of Events
April 18: Adopt-A-Spot litter pickup