Jefferson Lab Weekly Briefs

June 18, 2008

12 GeV Upgrade

The R&D task to re-measure the Higher-Order Mode (HOM) damping in the 12 GeV-style superconducting radio frequency (SRF) cavities is proceeding. Initial measurements are complete, and the data are being reviewed. The final lot of laminations for the prototype beam transport quadrupoles have been received from the vendor. Inspection is underway prior to beginning stacking quadrants.

Design status and safety reviews for three accelerator systems were held recently: the Cryogenics system, the Instrumentation, Controls & Safety systems, and the Beam Transport system together with the magnets of the Extraction system. The review panels found that the work is progressing well and is on track for completion consistent with the overall 12 GeV Upgrade Project schedule.

Physics

Data taking for E04-108 (Measurement of GEp/GMp at high Q2) was successfully completed in Hall C. The experiment successfully captured data at the highest momentum transfers for which the polarization transfer method of measuring proton form factors has been applied. In addition, facility development studies were done for the Q-weak experiment. These studies tested both a new type of luminosity detector and methods of minimizing asymmetry noise from target boiling. A large part of these studies was done parasitically to the experiment, allowing some of the time lost due to zero beam polarization to be recovered.

Accelerator

The Scheduled Accelerator Down began after nine hours of beam studies. The sitewide power transformer overhaul work was begun; it will continue with maintenance of one transformer at a time to limit disruptions to other maintenance activities. Injector work included electrode replacement and the installation of a direct current Verdi laser for cathode lifetime studies. The capture water supply pump was replaced, and vacuum leak checks in the North and South Linacs were started. Warmup of several cryomodules was started as the Central Helium Liquefier reduced cooling load prior to maintenance work on the CHL and running the facility at 4 Kelvin on the Standby Refrigerator (SBR).

Theory

In a new Theory Center paper, arXiv:0805.4629 [hep-lat], JLab staff and users review the status of lattice QCD calculations of hadronic interactions. In particular, computations of hadronic interactions (scattering lengths) in meson-meson and baryon-baryon scattering are considered. For mesonic systems, precision calculations have already been performed, while for the baryon sector, the authors argue that present-day computational resources, if devoted to these calculations, are capable of achieving reliable results.

 

 

 

Environment, Safety, Health & Quality

Floods are one of the most common hazards in the United States. Be aware of flood hazards no matter where you live, but especially if you live in a low-lying area, near water or downstream from a dam. Even very small streams, gullies, creeks, culverts, dry streambeds or low-lying ground that appear harmless in dry weather can flood.

Every state is at risk from this hazard. If a flood is likely in your area, follow these tips from FEMA to prepare:

  • Listen to the radio or television for information.
  • Be aware that flash flooding can occur. If there is any possibility of a flash flood, move immediately to higher ground. Do not wait for instructions to move.
  • Be aware of streams, drainage channels, canyons, and other areas known to flood suddenly. Flash floods can occur in these areas with or without such typical warnings as rain clouds or heavy rain.
  • If you must prepare to evacuate, secure your home. If you have time, bring in outdoor furniture. Move essential items to an upper floor. Turn off utilities at the main switches or valves if instructed to do so. Disconnect electrical appliances. Do not touch electrical equipment if you are wet or standing in water.
     

Additional flood information and resources can be found on the FEMA website.

Announcements

JSA Initiatives Fund Website Update
The JSA Initiatives Fund website has been updated. JSA partners – the Southeastern Universities Research Association and Computer Sciences Corporation/Applied Technologies Division – established the JSA Initiatives Fund to support programs, initiatives, and activities that further the scientific outreach, and promote the science, education and technology missions of Jefferson Lab in ways that complement its basic and applied research focus. Initiatives Fund awards are for those projects that benefit the JLab user community and leverage the commitments of others.

Red Cross Accepting Donations for Flood Relief
The American Red Cross is asking for donations to continue its flood relief efforts for those hardest hit in the Midwest. Donations may be made directly to the Red Cross on its website.

JLab's Safety Numbers

273 Days since Last Recordable Accident (JLab record: 319)
592 Days since Last Lost Workday Accident (JLab record: 592)

JLab Calendar of Events

June 30-July 2: Science & Technology Review
July 4: Independence Day Holiday (JLab closed)
July 8-10: DOE ES&H Inspection - Report Validation and Closeout
July 10-11: Teacher-to-Teacher Workshop at JLab
July 14-19: Lattice 2008
July 22-24: DOE Office of Science OPA Independent Project Review of the 12 GeV CEBAF Upgrade Project
July 22-25: Thin Film - Superconducting Radiofrequency Technology Workshop

 

 

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