Jefferson Lab Weekly Briefs June 8, 2011

Jefferson Lab Weekly Briefs
June 8, 2011

12 GeV Upgrade

At the request of the DOE Office of Nuclear Physics, the director of the Office of Project Assessment, Daniel Lehman, convened a Mini-Review of the 12 GeV Upgrade Project via teleconference on June 1. The panel was charged with evaluating the overall status of the project with particular focus on Hall B and responses to recommendations from the December 2010 review. The committee concluded that the project is progressing appropriately and the team is focused on the necessary Hall B subsystem issues. Recommendations were made regarding an update to the spend plan and scheduling the next full review in the October 2011 timeframe. 


Hall A has been de-installing the former experiment apparatus and preparing for the fall run. The technicians have removed the BigBite spectrometer, the target and parts of the beamline. It's a long process, but the work is proceeding at a good pace.


The third week of the six-month accelerator shutdown went well. The cables and CAMAC cards for the viewers and beam scrapers for the injector (PEPPo) project were in place. Removal and installation of west arc dipoles continued. The seven refurbished dipoles of Stack 1 (2A01) were installed and the alignment was underway. The microphonic and vibration measurements on superconducting radiofrequency cryomodule R100 were finished and the module was moved to 2L23. SRF cryomodule C100-1 was installed at 2L21, and the cooldown was started. W2 and W4 CAMAC to VME conversion was in progress; VME crate, modules and cables for iocwa4 were installed. Many other tasks were continued or started.

Free-Electron Laser

The FEL team spent the week dealing with leaky valves in the injector and planning a procedure that would allow replacement of the gun without endangering the cryounit booster.

Center for Theoretical and Computational Physics

It has been known since the 1960's that the exchange of vector mesons (such as rho, omega and phi) plays a prominent role in the nucleon elastic form factors at momentum transfers below ~1 GeV2. The idea of "vector meson dominance" can now be formulated rigorously in QCD, using the concept of transverse charge densities in a fast-moving nucleon. A recent dispersion analysis reveals that the transverse densities at distances b ~ 1 femtometer are maximally sensitive to vector meson exchange and quantifies the corrections from higher-mass exchanges. These results provide fresh insights into the nucleon's partonic structure and suggest new ways to study the couplings of vector mesons and their excited states in electron-scattering experiments.


Work on the 12 GeV beam transport in the accelerator's west arc is progressing better than anticipated. The installation group has removed 77 of 112 west arc dipoles from the tunnel. Twenty-one arc dipoles have been completely refurbished and had their respective H-Steel added. Magnetic measurements have been completed on six of the refurbished H-style arc dipoles. These six refurbished dipoles have been placed back in the beamline.

Five south linac warm region girders have been removed from the tunnel. These five girders have been reconfigured on the new 'short' style girders that are necessary to accommodate the upgraded cryomodules and are ready to be reinstalled.

Support for the Hall A g2p experiment has included the demolition of the impacted sections of beamline. This work has been completed. Additional activities have begun with the survey and drilling of the new stands which will support the g2p beamline.




Environment, Safety, Health and Quality

Simplified CPR
The American Heart Association has simplified its CPR guidelines. These can be reviewed in the AHA's 2010 Guidelines for CPR video on YouTube.

The guidelines emphasize that chest compression alone is valuable, even without rescue breathing. The target compression rate is approximately 100 per minute and the target compression depth is approximately two inches. When available, automated external defibrillators, or AEDs, are critically important and should be used as soon as possible.


Semi-Annual Personal Dosimeter Change Out Set for June 29
JLab's semi-annual personal dosimeter change out will take place on Wednesday, June 29, starting around 3 p.m. This includes the dosimeters of all JLab staff, users and subcontractors. If you need to use your dosimeter during the change out period, you may exchange it that morning in the Radiation Control Dosimetry Office in Bldg. 52B, Room 4, 8 a.m. - noon. If you have questions, contact Becky Mosbrucker, x7236. Everyone with a personal dosimeter is asked to place it in its assigned slot in the racks before the change out on June 29. If you will be away from the lab on June 29, please be sure to return your dosimeter to its place in the rack before you leave the lab. Remember to return your dosimeter to its assigned place in the dosimetry racks when it is not in use. Don't leave it in your desk or work area. Don't leave it in your car or where it will be exposed to direct sunlight.

Tracking Thomas at JLab
Little Thomas is visiting all corners of the JLab campus. If you can identify his location this week, email Kandice Carter with your guess. The first correct response will receive special recognition on this page. Guesses are accepted through Fridays.

Congratulations to Christopher Williamson, who was the first person to correctly identify the June 1 location. Honorable mentions go out to Elaine Zuchowicz, Tonya Evans, Karen Bartek, David Fazenbaker, Jim Follkie, Dennis Merritt, Connie Adams, Jason Willoughby and Allison Lung. Check out the Tracking Thomas webpage for a better view of his last location and this week's new mystery photo.

JLab Calendar of Events

June 6-8 Users Group Workshop and Annual Meeting
June 20: Safety Shoe vendor onsite
July 4: Independence Day holiday; JLab closed
July 11: Safety Shoe vendor onsite
July 29: Summer Intern Programs Poster Session

JLab Summer 2011 Education Calendar

May 31- June 17: Hampton University Graduate Studies
May 23 - July 29: Science Undergraduate Laboratory Internship
May 23 - July 29: Research Experience for Undergraduates
June 20 - July 29: High School Summer Honors Program
July 29: Summer Intern Programs Poster Session