Jefferson Lab Weekly Briefs
April 25, 2012

12 GeV Upgrade

The cryomodule voltage needed for delivering 12 GeV beam to Hall D is 98 Megavolts. This performance was demonstrated during a recent beam study period, when a C100 cryomodule was successfully operated at 98 MV for one hour. Both in-tunnel C100 cryomodules are now operating with piezo-electric tuner resonance control, resulting in substantial improvement in detuning. Installation of the compressors and 4.5 Kelvin coldbox for the Central Helium Liquefier - 2 continues. Procurement actions are underway for the box power supplies for the arc dipole magnets. Field measurements of the new curved dipole magnets for the beam transport spreaders and recombiners have been completed. The magnets met all specifications, including close approximation of the predicted shunt settings. Fabrication of the new stripline beam-position monitor cans continues.


In Hall A, the g2p / GEp experiments have been running smoothly this week, finishing several kinematic points. If the hall keeps running like this until May 18, it will be a nice success.

Hall C completed running with the 877 MeV beam. Using the Q-weak apparatus, the parity-violating asymmetry of the nucleon to delta transition was measured to a precision better than one part per million. In addition, non-parity-violating asymmetries with transversely polarized beam were measured for the nucleon to delta transition and for Moller (electron-electron) scattering. Q-weak is now measuring the asymmetry of inclusive scattering of 3.35 GeV electrons on hydrogen. This measurement will constrain the uncertainty on one of the largest corrections to the measurement of Q-weak.

Voting in Users Group Elections Open Through April 30
The annual election for new members to the JLab Users Group Board of Directors (UGBoD) is underway. This body represents all the researchers who use Jefferson Lab facilities – to the lab and the world at large. Biographical sketches of the candidates can be accessed through the ballot page. The election will close at 5 p.m. EDT on Monday, April 30. Newly elected members will be announced at the 2012 Users Group Meeting, and their terms will begin after the meeting.


The accelerator completed its low-energy run. The C100 radiofrequency zones ran at relatively lower levels, while preparations were made to push for higher gradients, which was planned for Thursday. On Thursday, a mini-scheduled accelerator down/beam studies day was taken in preparation to return to high energy. Preparations were also made to support high beam loading for the C100 zones. The injector experiment, PEPPo, tests were carried out in parallel with RF recovery and work on C100 zone 2L25. During the workday, tours for the NASA pressure vessel group and Beam Instrumentation Workshop were conducted. The accelerator energy was increased and all halls were reconfigured to new passes. The configuration change continued through Friday, with all halls taking low current until Saturday. During the weekend, the accelerator was configured for high current Hall C running. Operations staffers delivered 150 microamp beam to Hall C at 3-pass, with C100 zones set at 70 MeV each. Beam was terminated to Hall B on Sunday for planned work on the HDice target.

Free-Electron Laser

The FEL continued to run well for 16 hours a day, with day shifts for 2.2 micron mirror tests and wall plug efficiency studies, and evening shifts for terahertz users and Darklight experiment background measurements.


The Mechanical Systems Installation group recently completed many tunnel low-conductivity water leak repairs in a single day, resulting in an 85 percent reduction of LCW loss. Other LCW work supporting the 12 GeV Upgrade has been started, including the tagger dump skid installation and the beam switchyard service building LCW header upgrade.

A new 12 GeV floor-to-ceiling stand was temporarily installed at the tagger dump to Hall D, allowing for the validation of new tooling for the stand. Additionally, the ceiling stand was used by the Survey and Alignment group to train new staff on stand alignment. A ceiling plate test fixture, a ceiling plate install lift and an overhead ceiling plate drill press were added in support of the upcoming 12 GeV down.

The vacuum group has also made a lot of progress to support the upcoming 12 GeV down:

  • 70 dipole vacuum chambers were cleaned and leak checked;
  • 51 beam position monitors were leak checked;
  • 7 quadruple girders were assembled;
  • and two insertable dumps were assembled and leak checked.
  • Both the installation and vacuum groups have continued to support ongoing accelerator operations for the current 6 GeV physics run.

Environment, Safety, Health and Quality

When planning work at JLab, each group should always have some type of plan for what will occur. Some of these plans are formal written documents, with a completed Task Hazard Analysis (THA). During this work, there may be short, quick jobs that may not have been covered in the THA or rise to the level of hazard requiring a THA. A simple review, called the SAFE Plan, can help avoid hazards and serious potentials. The SAFE Plan is:

  • Summarize the critical steps of the task. Determine where you are in the job and pick out the features that have safety implications.
  • Anticipate the unexpected; review elements of the THA that are relevant to today’s activities.
  • Foresee consequences; anticipate what is the worst thing that can happen?
  • Eliminate or mitigate hazards; what specifically is keeping me safe on the job? How will I maintain my focus and awareness?

Computing and Networking Infrastructure

Email Migrations into New System Ongoing
The CNI group is continuing to migrate staff and some users into the new email and calendar suite, Zimbra. These migrations are going well, with nearly 300 staff and users migrated into Zimbra and about 250 still left to migrate. These migrations are occurring overnight, and you will receive an email around noon on the day you are scheduled to be migrated. For more information, see the article in the March 16 OnTarget newsletter.


Education Seeks Projects for Summer Honors Interns
JLab's Science Education team is seeking ideas and suggestions for projects, and project and mentor volunteers, for the lab's 2012 High School Summer Honors Program, June 25 to Aug. 3. Students chosen for the program will have a strong academic record and a strong desire to learn about the lab's science and technology. Lab scientists, engineers and other technical managers who are interested in serving as a mentor to these high-achieving high school students and have a project, or number of projects, to be accomplished this summer, are asked to send a description of the work to be assigned to Brita Hampton, x7633, by May 1.

Colloquium: From Quarks to Baseballs - The Evolution of a Physicist
Alan Nathan, University of Illinois at Urbana-Champaign, will address some interesting and practical questions of baseball from a physics perspective. In this talk, he will discuss some of the ways that a physicist analyzes the game of baseball. The talk will be organized around two broad topics: The physics of the ball-bat collision and the aerodynamics of a baseball in flight. The goal is that all will enjoy this talk, whether your interest is physics, baseball, or the intersection between them. The colloquium will take place May 2 at 4 p.m. in the CEBAF Center auditorium.

RadCon Seminar: Anticipating Radiation Damage: Calculation of Relevant Quantities
Even non-biological matter can suffer serious consequences from radiation, both natural and artificial. Francesco Cerutti, Emerging Energy Technologies Section of the Engineering Department at CERN, will review the macroscopic quantities associated with different types of damage, such as absorbed dose, displacements per atom, high-energy hadron fluence, and silicon 1 MeV-equivalent neutron fluence. The calculation of these quantities will be discussed in the context of the Monte Carlo description of the radiation-matter interaction, with particular reference to the FLUKA code. The seminar will take place Friday, May 4 at 1:30 p.m. in CEBAF Center Room F113.

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. Guesses are accepted through Friday.

Congratulations this week go to John Fischer, Dan Moore, Harry Fanning, Narciso Gomez, DeAnn Maddox and Karen Bartek, who were the first to correctly identify the April 18 location. Honorable mentions go to Casey Heck, Debra Brand, Ron Bartek, Angie Thomas, Subashini De Silva and Mike Martin. 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

April 25: JAG Run-A-Round
April 30: FLUKA Training Course
May 2: Colloquium and Public Lecture
May 7: Safety Shoe vendor onsite
May 9-11: Science and Technology Review
May 14-17: QCD Evolution Workshop
May 19: JLab's 2012 Open House: Passport to Science
May 28: Memorial Day holiday, JLab closed