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.

Accelerator

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.

Free-Electron Laser

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.

Theory Center

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)
301 Days since Last Lost Workday Accident (JLab record: 676)

JLab Calendar of Events

July 13-17: Tunnel Housekeeping
July 14-16: JLab Science and Technology Review
July 24: FEL Photon Science Workshop
July 29: American Red Cross Blood Drive
July 31: Science Education Summer Poster Session

 

 

 

Environment, Safety, Health & Quality

Attention JLab Supervisors!
As we are well into the summer Scheduled Accelerator Down (SAD) period, now is a good time to check your welding personnel qualification renewals to ensure that they are current.

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.

References:
ES&H Manual 6122 Appendix T6 Welding and Brazing Program
ASME section IX QW-322.1 Expiration of Qualification
AWS D1.1 section 4.1.3.1 Welders and Welding Operators

Computing and Networking Infrastructure

Network Outage This Saturday, July 11, 8 a.m.-1 p.m.
The CNI group is planning work on the JLab network during the morning of July 11. Users and staff at the lab during this time will experience several short outages, and some portions of the network may experience a brief outage while the group makes some needed configuration changes. Access to the Internet may also be briefly interrupted.

Maintenance Day, Tuesday, July 14, 5-10 p.m.
The CNI group is planning a maintenance period from 5-10 p.m. on Tuesday, July 14. During this period, jlabl1 and jlabl3 will be rebooted. In addition, patches will be pushed out to all Computer Center-managed systems. To insure that the patches will install correctly with the least inconvenience, log out of your system when you leave on July 14, but leave the system powered up overnight to receive the patches. Plan on rebooting your system on July 15 after the patches have been delivered. If you experience issues with your system after the reboot, contact the Helpdesk at x7155.

Announcements

Cholesterol Screenings Will Be Held July 13-17
Anyone interested should call Occupational Medicine at x7539 to schedule an appointment. If you have received this test within the last year, this includes Medical Monitoring, please let others take advantage of this opportunity.

American Red Cross Blood Drive
The next American Red Cross Blood Drive is scheduled for Wednesday, July 29, from 10 a.m. - 4 p.m. in CEBAF Center room F113. New and repeat donors are encouraged to attend. Walk-ins are welcome; however, making an appointment allows the Red Cross to schedule adequate staff for the visit. Volunteers are also needed to help with the blood drive. To schedule an appointment or to volunteer, contact Johnie Banks at x7539 or  jbanks@jlab.org.