Jefferson Lab Weekly Briefs November 19, 2008

Jefferson Lab Weekly Briefs

November 19, 2008

12 GeV Upgrade

JLab jointly sponsored an international workshop on Physics and Methods in Meson Spectroscopy in Munich Oct. 22 - 24 with more than 80 participants. The workshop encompassed meson spectroscopy with beams of protons and mesons (CERN-COMPASS), polarized photons (JLab-Hall D/GlueX) and antiprotons (GSI/FAIR-PANDA). Part of the workshop program dealt with the new analysis methods presently being developed to make optimal use of these high-statistics data sets and to improve the reliability of traditional partial wave analysis. The workshop was a great success, bringing experts from all over the world together to discuss this physics and the associated analysis methods. More information can be found online.


In Hall C, the Spin Assymetries of the Nucleon Experiment (SANE) is down because of problems with the superconducting magnet in the polarized target. After a five-day warmup, the magnet was transported to the EEL and the top "donut" opened. Unfortunately, no obvious fix was found. Oxford, the company that built the magnet, quoted six weeks to assess the magnet. With the time constraints in the beam schedule, sending the magnet to Oxford would be a delay that wouldn't allow the experiment enough time to run. So Hall C staff is going to continue studying the magnet at JLab to see if the problem can be isolated.


The accelerator provided 184 hours of beam to the two experimental halls during this period. The accelerator’s beam availability was reduced by two significant equipment events related to the Central Helium Liquefier. A Howden Compressor Oil Pump bearing failed, which required taking the CHL offline to replace the bearing. Unfortunately, soon after this problem was fixed, the CHL’s Turbine No.T3 had to be replaced. This repair effort was further delayed by the discovery of a faulty turbine seal on the replacement turbine. Once all repairs were successfully and safely made, the accelerator resumed beam delivery.

Free-Electron Laser (FEL)

FEL staff replaced the gun cathode and completed a short bake over the weekend. The gun had provided good current, but lifetime on the cathode was limited by field emission points from the cathode due to earlier damage. While working on that, staffers also made significant progress on stabilizing phase noise on the Advanced Drive Laser.

Theory Center

JLab has already played a major role in the exploration of strange quarks in the nucleon, providing a large part of the world's data on parity-violating electron scattering. For lattice QCD, the measurement of strange quark contributions involves so-called disconnected diagrams, which have proven extremely hard to measure. Indeed, the best determinations of the strange electric and magnetic form factors have come through indirect means. In recent work (arXiv:0811.1779 [hep-ph]), led by colleagues at the University of Kentucky, state-of-the-art methods were used to establish that the strange and anti-strange quarks in the nucleon carry about 2.7 percent of the momentum of the nucleon, with an error which puts this result almost 5 standard deviations from zero.

JLab's Safety Numbers

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

JLab Calendar of Events

Nov. 21-22: Lattice QCD and Experiment: Revealing the Structure of Hadrons
Nov. 27-28: Thanksgiving holiday - JLab closed
Dec. 3: Colloquium and Public Lecture
Dec. 8-12: Muon Collider Design Workshop
Dec. 24-Jan. 2: Winter holidays/Shutdown days: JLab closed

Environment, Safety, Health & Quality

Update (11/21/08): This ES&H Manual Chapter 6122 update is not complete. The chapter is currently being updated, and and an update will be available soon.


As part of Continuous Improvement efforts, ES&H Manual Chapter 6122 Appendix T6 Welding and Brazing Program has been revised to incorporate updates that respond to the initial implementation of the program. The revision was made with the feedback of line users, addressing items such as repairs, required analysis, category clarification and additional examination requirements of Class B joints. The revisions have been approved and are posted to the website for site use. All ES&H Manual Chapter and Appendix updates will be announced in the Weekly Briefs as they occur and will be listed on the Insight page under JLab Safety Snapshot. Review these sources periodically for up-to-date information.

Computing and Networking Infrastructure

JLab Under Cyber Attack
The Department of Energy has authorized cyber security experts, called Red Teams, to test computer security at the national labs. These teams have been active recently and may target Jefferson Lab in the coming weeks.

Red Team activities can include attempts to hack into lab computer systems from both offsite and onsite. Recent Red Team attempts to get a toehold in a lab's network have been made through phishing and social engineering. Some successful examples include the sending of official-looking CDs in the mail or leaving a memory stick in a public place that installs Trojans when inserted into a computer, sending official-looking e-mails with embedded web links to malicious websites, and placing phone calls to users claiming they represent the Helpdesk.

Here are a few quick tips on practicing good cyber security:

  • Do not open any e-mail attachments that are suspicious (unknown sender, unexpected e-mail with an attachment or asking for information, etc.);
  • Do not click unknown links in e-mails (fake greeting card links, html addresses you can't see or identify in plain text, links in unsolicited e-mail from a bank, etc.);
  • Do not use a CD or memory stick from an unknown source;
  • Never give out your password or other identifying information to someone else, even if they are claiming to be JLab staff;
  • Always lock your screen or log out of your computer before you leave your office.

These links provide useful information about thwarting cyber security attacks:


Holiday Desserts to Tempt Your Taste Buds
The Quark Cafe is now taking Thanksgiving dessert orders. The deadline for pie orders is 2 p.m. on Friday, Nov. 21. Order forms and a full list of desserts are available in the cafeteria.

Mobile Mammography Unit Onsite Dec. 8
The Sentara Mobile Mammography Unit will be in the ARC parking lot at Jefferson Lab on Dec. 8, from 9 a.m.-2 p.m. Mammography detects breast cancer, and The American Cancer Society recommends scheduling your first or baseline mammogram by age 40. The procedure only takes 15 minutes. This service is open to all employees, as well as their family members or friends; personal health insurances will be billed. To make an appointment, call 1-800-SENTARA (736-8272).

Quark Cafe Invites Your Input Through Online Survey
Quark Cafe staff members highly value your input and want to ensure that food service quality and service levels meet or exceed your expectations. Completing this survey will take less than five minutes. The information you provide will help the Quark Cafe strengthen its levels of food service and prioritize improvement efforts to ensure the highest levels of customer satisfaction. This survey is strictly confidential. Take a moment to complete the survey by clicking on the link. The link will remain open through Dec. 3.

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