Jefferson Lab Weekly Briefs
November 11, 2009

12 GeV Upgrade

A system requirements review for the toroid magnet for CLAS12 was held at JLab, marking the start of construction of this key superconducting magnet. An initial review for the construction of the Q1 quadrupole magnet for the Super High Momentum Spectrometer (SHMS) was held at the vendor's offices, Scientific Magnetics in Abingdon, Oxfordshire, in the U.K., also in October. The best and final offers for the cryogenic reservoirs for all five superconducting magnets for the SHMS were received and are being evaluated; this procurement also will include the cryogenic reservoir for the solenoid magnet for Hall D. First full-size prototype arrays were received for the silicon photomultiplier option for the optical readout of the Hall D Barrel Calorimeter detector. These were inspected and shown to be fully operational, with good gain and rise time, and are now undergoing detailed test evaluation.

Physics

Hall B is running the first physics production run at JLab with a beam energy greater than 6 GeV. The eg6 run group covers two experiments with very different physics goals but using a common pressurized helium gas cell as a spin-0 scattering target and a low-density radial time-projection chamber (RTPC).

Experiment E07-009 searches for hybrid mesons in the quasi-real photoproduction of mesons off helium-4, where the nucleus remains intact and is detected in the RTPC. The quantum numbers of the helium nucleus limit the number of possible spin-parity combinations for excited mesons and enhance production of mesons with "exotic" quantum numbers that cannot occur in ordinary quark-model states.

Experiment E08-024 runs in parallel and probes the quark structure of the helium-4 nucleus in terms of generalized parton distributions using coherent and incoherent production of high-energy photons through the deeply virtual Compton scattering process. If the handbag mechanism works for helium-4 as it does for hydrogen, the nucleus is described by a single leading twist GPD "H" (compared to four GPDs for protons), which makes the interpretation much simpler. Moreover, the comparison of single spin asymmetries from helium-4 and from the proton is sensitive to the role of transverse degrees of freedom in the nuclear structure and their contribution to the EMC Effect.

Accelerator

The accelerator energy was changed from 5.764 GeV to 6.068 GeV. The GUN2 photocathode was heated and re-activated to provide good quantum efficiencies. Radiofrequency cavities were optimized for high-energy and high-current running. Beam delivery was resumed on Wednesday. After the energy change, the Hall A Compton counts are high, and the accelerator experts have been troubleshooting the problem.

Free-Electron Laser

FEL staffers were given an unexpected opportunity for operations this week, and they completed a run for the Light Pseudoscalar and Scalar Search collaboration dark matter experiment. The team learned a lot about the machine from the optimization necessary for this successful beam delivery. LIPPS did six complete runs, typically receiving 500 Watts on the target at a 930-nanometer wavelength. Analysis of the data is underway.

JLab's Safety Numbers

119 Days since Last Recordable Accident (JLab record: 331)
427 Days since Last Lost Workday Accident (JLab record: 676)

JLab Calendar of Events

Nov. 12: Safety Shoe Vendor onsite
Nov. 16: Women in Science and Engineering Workshop
Nov. 26-27: Thanksgiving holidays - JLab closed
Dec. 5: JLab Children's Holiday Party
Dec. 10: Safety Shoe Vendor onsite
Dec. 24 - Jan. 1: Winter holidays/Shutdown days - JLab closed

 

 

 

Environment, Safety, Health & Quality

Good safety practice calls for anyone at JLab using a golf cart between dusk and dawn to drive with the golf cart's headlights on. Golf carts that don't have headlights may not be used from dusk to dawn. The Feb. 28 Integrated Safety Management poster titled Motorized Cart Safety offers a list of safety rules, including: Carts operated between sunset and sunrise shall have and operate with headlights turned on. The ISM posters are archived in Docushare.

Computing and Networking Infrastructure

JLab Wireless Access Changes
On Saturday, Nov. 14, the CNI group will upgrade JLab's wireless network. This new system will allow the group to expand coverage and increase security. At this time, you will not need to change how you connect to the wireless network via 'jlab_secure' or 'jlab_guest'. The group is adding a new wireless network, called 'jlab', that users may begin migrating to after the upgrade. The new network will replace 'jlab_secure' on Dec. 7.

Linux Patches To Be Sent Out Tuesday
The CNI group is planning to push out Redhat Linux patches to all desktops on Tuesday evening, Nov 17. Plan to reboot your Linux system sometime on Nov. 18 to complete the patch installation. If you encounter problems with your system, contact the Helpdesk at x7155.

Windows Patches To Be Sent Out Tuesday
The CNI group will install all the latest Service Packs to all Windows systems on Tuesday evening, Nov. 17, along with other critical/security patches. The latest Service Packs are:
Windows 2000 - Service Pack 4, Windows XP - Service Pack 3, Windows Vista - Service Pack 2 and MS Office 2007 - Service Pack 2.

Announcements

Performance Appraisals
The deadline for all appraisals to be completed and presented to employees is only a month away. With the Thanksgiving holiday coming, that leaves less time than one might think. To obtain a PIN to work offsite or get answers to questions that may be holding you up, contact Bruce Ullman at x7170 or Cassandra Andrews at x7068.

Hand Sanitizer for Your Workspace
To minimize the spread of flu this season, JLab purchased bottles of hand sanitizer and disinfectant wipes for distribution to staff and users for disinfecting hands and common-use workplace surfaces, such as phones and keyboards. If you haven't yet received your personal allotment, you can obtain supplies from the Stockroom, Bldg. 90, between 8 a.m. and 4 p.m., Monday-Friday. If you have any questions, contact x7225 or x7233.

Large Bottles of Hand Sanitizer Now in JLab Public Areas
Large bottles of hand sanitizer have been placed in JLab public areas and conference rooms. The bottles should last throughout flu season, but if a bottle runs out, or if an area was overlooked, please notify the Stockroom at x7225.


JLab Jackets Available for Purchase
JLab 25th Anniversary Jackets may be purchased for $36.50 per jacket at the CEBAF Center front desk. Sizes available for purchase include small, medium, large, X-large, 2X-large and 3X-large. Payment can be made by cash or personal check addressed to Jefferson Science Associates, LLC. Exact change is appreciated.

Interested In Ordering the Liner for Your JLab Jacket?
If you are interested in purchasing the matching Charles River liner for your JLab jacket, e-mail Michelle Lechman no later than Friday, Nov. 20. If enough interest exists in the liners, Public Affairs will assist in placing a one-time order. The cost per liner will be based on the number of individual orders and is expected to be between $30 and $40. If the decision is made to order liners, the price will be advertised and those interested will need to pay for their liner in advance. Individuals who put their name on the list during the last distribution sessions do not need to resubmit their names. If you have fleece or other jackets with the same style of zippers found on your JLab jacket, they may fit the liner zipper.

Food Drive for Foodbank Underway
The JAG is sponsoring a food drive through Nov. 20 to support the Foodbank of the Virginia Peninsula. Especially needed are peanut butter, nuts, dried fruit, canned meats and tuna, canned vegetables, cereal, crackers, rice and chunky soups. No perishable food items or food in glass or breakable containers will be accepted. Drop barrels have been placed in CEBAF Center, the MCC, Test Lab, VARC and ARC.

Quark Cafe Offers Thanksgiving Feast
Quark Cafe staff will host a Thanksgiving Buffet from 11:30 a.m. to 1:30 p.m., Thursday, Nov. 19. For $8.99, patrons get the buffet spread, which includes one plate, a 24 oz. fountain drink and a dessert. The buffet will feature buttery sage and thyme-roasted turkey with home-style gravy, carved Smithfield ham, roasted duck with wild mushroom demi-glaze, maple-roasted glazed butternut squash, fresh herb dressing, green beans almandine, Yukon gold smashed potatoes, sweet potato casserole, fresh cranberry relish, dinner rolls and a selection of scrumptious desserts.

Holiday Desserts to Tempt Your Taste Buds
The Quark Cafe is now taking Thanksgiving dessert orders. Selections include apple, pumpkin, pecan and sweet potato pies and pumpkin cheesecake. The deadline for orders is 2 p.m. on Friday, Nov. 20. Order forms and a full list of desserts are available in the cafeteria.