Jefferson Lab Weekly Briefs
July 8, 2009
12 GeV Upgrade
On the Central Helium Liquefier (CHL) Building Addition, the footings are 50 percent complete, and the contractor is working on the trench. The trench is T-shaped and runs the full length of the addition in both directions. The trench is for gas and cooling water pipes running to and from the compressors that will be housed in the addition. Structural steel for the building addition was delivered to the construction worksite last week.
The City of Newport News has approved the traffic signal plan for the Hall D construction entrance off Canon Boulevard. The construction contractor is working on installation of utilities (water and electrical) and the construction entrance.
The Scheduled Accelerator Down continued with maintenance on trim magnets, box power supplies, vacuum rack power supplies, the personnel safety system, RF (radio frequency) cavities, diagnostic systems and more. Waterproof injection for groundwater leaks at the Hall A truck ramp was completed. Gun2 was vented and is ready to be removed.
Last week was spent providing light to the Light Pseudoscalar and Scalar Search experiment search for dark matter. Although FEL staff did not meet all of their goals, and the machine is not yet running at full output, there was modest success providing initial alignment beam and then several hundred watts of laser light at 930 nanometers to the test setup. The machine ran through four lightning strikes Thursday night before the fifth blew out an RF system and tripped the machine off.
In a new paper <arXiv:0906.5323 [hep-ph]>, relations between generalized parton distributions (GPDs) and transverse momentum dependent distributions (TMDs) that were suggested in the literature are investigated by means of an analysis of common "mother functions" of GPDs and TMDs -- so-called generalized transverse momentum dependent parton distributions (GTMDs). This work deals with GTMDs for a spin-1/2 hadron (nucleon) and is a natural extension of a previous work for a spin-0 hadron. Despite the fact that relations between GPDs and TMDs (in particular an experimentally verifiable relation between the Sivers function and the GPD E) were established in certain models, it is found that no nontrivial exact relations between GPDs and TMDs can exist model-independently.
JLab's Safety Numbers
184 Days since Last Recordable Accident (JLab record: 331)
JLab Calendar of Events
July 13-17: Tunnel Housekeeping
Environment, Safety, Health & Quality
Attention JLab Supervisors!
ASME (American Society of Mechanical Engineers) Section IX, American Welding Society (AWS) and the JLab ES&H Manual require that a welder or welding operator perform a welding process at least once every six months in order to maintain that particular qualification. At JLab, supervisors are responsible for ensuring and documenting this semi-annual performance. Processes include Gas Tungsten Arc Welding (TIG), Shielded Metal Arc Welding (Stick), and Brazing with Oxygen and Acetylene. Welders or operators are not required to take a qualification test but only to demonstrate their abilities to use these processes. This can be done on production welds or practice weld plates and pipes, provided that the weld is at least six inches in length. For help or qualification renewal suggestions, contact Michael Martin, x5515.
Computing and Networking Infrastructure
Network Outage This Saturday, July 11, 8 a.m.-1 p.m.
Maintenance Day, Tuesday, July 14, 5-10 p.m.
Cholesterol Screenings Will Be Held July 13-17
American Red Cross Blood Drive