Jefferson Lab Weekly Briefs December 19, 2007
Jefferson Lab Weekly Briefs
December 19, 2007
Site Power Outage
The Test Lab electrical substation will be taken offline over the holiday break to replace aging equipment. The power outage will begin at noon on Friday, Dec. 21. The following buildings will be without power: EEL, Test Lab, CEBAF Center, Buildings 31, 33, 52, 54, 57, & 59, Rad Con Trailers 52A, B, C, Trailers 34A, 34B, 34D & Safety Trailer (35). Electrical power will remain off in these buildings until Dec. 31. No one will be allowed in these buildings until after 8 a.m., Jan. 1, 2008. For additional information, please see the website or contact Paul Powers at ext. 7258.
12 GeV Upgrade
The main focus of attention for the 12 GeV Upgrade of Halls A, B, C and D is now the Project Engineering and Design for the various components in anticipation of the Critical Decision 3 reviews next summer followed by the start of construction. Associated with this, a series of design and safety reviews of various major experimental equipment subsystems is being planned for January through May, 2008. Two internal detector reviews, Hall C and Hall D, are scheduled for the second half of January.
Experiment E04-019, a study of two-photon contributions to ep elastic scattering using recoil polarization, is continuing to take production data in Hall C. Measurements are made at a momentum transfer of 2.5 (GeV/c)2, using three different beam energies. Data taking has completed for one of these data points, using a 2.84 GeV beam. Data taking has started for the 1.87 and 3.6 GeV measurements; these measurements will be completed in January.
Free-Electron Laser (FEL)
The FEL ran full time last week and made excellent progress in high-voltage conditioning of the new Gun Test Stand and made a new record for these coated electrodes. In addition, the FEL gun was prepared for a bakeout.
In two recent publications (Phys. Rev. C76, 065201 (2007) and arXiv:0712.2283 from the Excited Baryon Analysis Center (EBAC), results from dynamical coupled-channel analyses of pion-nucleon scattering and pion photoproduction have provided new information on the quark-gluon substructure of the nucleon excited states (N*). The structure parameters associated with 20 N* states have thus been determined. This advance has paved the way for accomplishing EBAC's goal of analyzing the world's data on photoproduction and electroproduction of pion, two-pion, eta, omega, and K mesons.
JLab's Safety Numbers
91 Days since Last Recordable Accident (JLab Record: 319)
JLab Calendar of Events
Dec. 24-Jan. 1: Holidays/Shutdown Days
Environment, Safety, Health & Quality
As we move into the holiday period, many of us were involved in decorating during the past few weeks with our friends and families. The National Safety Council recently provided these holiday safety tips:
Recognizing Changed Workplace Conditions Lesson Learned
Computing and Networking Infrastructure
Scientific Computing Outage
Network Outage Dec. 21
Site Power Outage Ramifications
End-Of-Year TLD Change out
Holiday Shutdown – Cafeteria Meal Notice
JLab Children's Holiday Party Photos