Jefferson Lab Weekly Briefs
July 21, 2010
12 GeV Upgrade
Civil construction for the 12 GeV Upgrade is now 25 percent complete. The North and South Access Building additions have taken shape, with the structural steel and metal siding installed. At Hall D, the last 10 feet of the walls is being framed with structural steel. A portion of the concrete floor for the tagger area has been placed and the contractor is installing the reinforcing steel for the remaining portion of the concrete floor. The contractor for the Central Helium Liquefier (CHL) utility upgrades has mobilized and the new transformer and switchgear at the South Linac is being installed.
In Hall C, installations of the Q-weak experiment, upgraded beamline and high-power cryotarget are complete. Preparations for helium and hydrogen cool downs of the target are underway and will be followed by tests with beam. The first beam in eight months was recently delivered to Hall C. This low-current beam was used for the initial checkout of Q-weak detectors and the new beamline.
This past week, the accelerator was up and beam available but none of the experimental halls took beam. Hall A started the summer down for installation. Hall B was down due to issues with its target, and Hall C was down, because work on the Q-weak target was not complete. The accelerator was used for beam studies and measurement of the quality factors of the cavities. The CHL tripped Saturday and was quickly recovered.
The FEL team continues to make progress toward ultraviolet lasing, although issues with the wiggler chamber welding have led to a slip to the third week of August for first try at oscillation. The team did complete the optics installation and verified that instrumentation works properly. The FEL hosted a visit by two DOE Basic Energy Sciences program managers for a tour of the FEL and discussions on accelerator R&D.
Several experiments aimed at studying parity violation in low-energy processes involving few-nucleon systems are being completed or are in an advanced stage of planning at cold neutron facilities (LANSCE, NIST and SNS), with the primary objective of determining the fundamental parameters of hadronic weak interactions (HWI), in particular the strength of their long-range component mediated by one-pion exchange. The determination of these parameters requires evaluating matrix elements of HWI operators between eigenstates of the strong-interaction Hamiltonian and, as a result, experiments in this field are especially reliant on theory for their analysis and interpretation. A new paper <arXiv:1007.2052> provides a detailed theoretical study of the (parity-violating) longitudinal asymmetry in the charge-exchange reaction 3He(?n,p)3H (whose measurement is being planned at the SNS), based on state-of-the-art interactions and wave functions.
Facilities Management and Logistics
Site Construction Updates
Note that all road and parking lot striping work is weather dependent. If it rains during the scheduled work period, the work will be rescheduled.
Environment, Safety, Health & Quality
Back injuries are a leading cause of lost work time. The types of back injuries include: strains, sprains, bulging and herniated disks. Remember to protect your back by:
You can consult with Industrial Hygiene (Dick Owen, x6381) regarding exposure to workplace hazards and Occupational Medicine (Johnnie Banks, x7539) regarding your working conditions. Occupational Medicine staff may be scheduled to conduct an ergonomic assessment for you. Together, Industrial Hygiene and Occupational Medicine can recommend improvements that will make your work-life safer and healthier.
Computing and Networking Infrastructure
Redhat Enterprise Linux Version 3 Support Ending
American Red Cross Blood Drive
August Beam Physics Symposium Honors Yaroslav Derbenev
New SOTR Training And Certification Process
JLab's Safety Numbers
84 Days since Last Recordable Accident (JLab record: 331)
JLab Calendar of Events
July 28: American Red Cross Blood Drive