Jefferson Lab Weekly Briefs
February 22, 2017
12 GeV UpgradeThe Torus magnet for CLAS12 was brought back down to liquid helium temperature at the end of January to prepare for the CLAS12 Key Performance Parameter beam commissioning run reported recently. The magnet operated without incident for the entire run. It was then kept at 4 Kelvin for two weeks to gain operational experience with the cryogenics and make incremental improvements to the control loops.
The central sections of the radiation shield of the Solenoid magnet have now been installed over the five coils making up the magnetic circuit and the resultant assembly covered with 25 layers of multilayer insulation. The entire cold mass was then again suspended from a temporary central support pipe and moved inside the barrel section of the outer vacuum cryostat, which itself had been placed in a support cradle that in turn will later serve as a shipping support fixture. The cold mass is suspended from the vacuum cryostat via eight thermally isolating support links, which are joined to the cryostat via specially shaped stainless-steel pockets that are now welded to the cryostat. The remaining sections of the radiation shield, which include the end cones, endcaps and central bore are being prepared by attaching their respective blankets of multi-layer insulation. The several dozen wires from the temperature and voltage sensors located on the Solenoid’s cold mass are being terminated in preparation to being attached to the main instrumentation feedthrough. The next major step is then transferring the load of the cold mass to the outer vacuum cryostat, after which the remaining sections of the radiation shield can be attached and the closure of the cryostat started. Planning for shipping the Solenoid to Jefferson Lab is well underway, with the shipping cradle being welded up prior to adding the isolation springs needed for the road trip to Virginia. The contract for the shipment has been awarded and includes a practice run with the shipping cradle in the near future over the highways to Pennsylvania in order to check g-forces encountered while driving along the roadway.
Hall A has been able to begin an opportunistic science run for Experiment E12-14-012, "Measurement of the Spectral Function of 40Ar through the (e,e2p) Reaction." This data will provide the only available high-statistics sample of electron scattering single nucleon knockout data for Argon, experimental input indispensable to constructing the spectral function. Besides yielding previously unavailable information on nuclear structure and dynamics, this fundamental information is needed to achieve a quantitative description of neutrino-nucleus cross sections in the kinematic regimes relevant to upcoming and future neutrino experiments, such as the Deep Underground Neutrino Experiment (DUNE). In addition, the analysis of the (e, e'p) data will promote further theoretical developments, such as the description of final state interactions, necessary for the correct interpretation of events collected by these neutrino experiments.
The first physics run of GlueX is underway in Hall D. The accelerator performance is good. An 11.7 GeV electron beam has been delivered to the Tagger Hall, where it interacts with a thin diamond crystal and radiates high-energy photons, linearly polarized in the range of 8-9 GeV. The collimated photon beam is delivered to the liquid hydrogen target of the Hall D solenoidal spectrometer. Selected interactions are recorded at a rate of about 30 kHz. It is an exciting time for the GlueX Collaboration, which met last week at Jefferson Lab for the regular trice-year meeting.
Jefferson Lab Published Journal Articles, Feb. 12-18
If you’re new to the lab or are writing your first journal article or proceedings paper, the next Publications Training and Refresher course is for you! This 45-60 minute course will be held on Friday, Feb. 24, at 10:00 a.m. in CEBAF Center room F224-225. After this session, you will be prepared to:
JSA/JLab Graduate Fellowship Program Now Taking Applications
The JSA/JLab Graduate Fellowship Program contributes to addressing the nation's commitment to grow our future science leaders and researchers by providing the environment and financial resources for graduate students to work alongside Jefferson Lab researchers. Application materials are due by March 10. More information and application requirements can be found online.
Apply Now for Sabbatical and Research Leave Support at Jefferson Lab
The JSA/JLab Sabbatical and Research Leave Support Program enhances research opportunities for faculty through access to Jefferson Lab facilities and interaction with Lab researchers and users, strengthens the teaching and research capabilities of universities through faculty involvement, and strengthens the research programs of Jefferson Lab by attracting "new blood" and integrating university faculty members in the laboratory's programs. Application materials are due by March 31. More information and applications requirements can be found online.
Center for Theoretical and Computational PhysicsSince the discovery of the J/Ψ meson over 40 years ago, production of heavy quarkonia is still arguably one of the most fascinating subjects in strong interaction physics, and theorists have not been able to fully understand its production mechanism. Within the non-relativistic QCD (NRQCD) approximation, the J/Ψ production cross section is often presented by summing over the production of various color-spin states of a pair of charm-anticharm quarks, weighted by NRQCD matrix elements characterizing the probabilities for the given states to transform into an observed J/Ψ. This new paper proposes and demonstrates that measuring the polarization of J/Ψ within a reconstructed jet provides not only a complementary measurement of, but also more stringent constraints on, the NRQCD matrix elements and the underlying J/Ψ production mechanism.
Environment, Safety, Health and QualityBe Prepared to Run, Hide or Fight if Faced With an Active Threat Situation
Recently, Emergency Manager Tina Menefee initiated an awareness campaign to help prepare the Jefferson Lab community in the event of an actual emergency. She is kicking off the effort with a poster highlighting critical things to consider if you are faced with an Active Threat situation where you may need to react by taking Run, Hide or Fight actions.
If faced with an Active Threat situation – you see someone brandishing a gun or other weapon, or any implement being used to cause harm to people or lab facilities – you should consider yourself to be in immediate danger. To best protect yourself and colleagues, you will need to quickly take action appropriate for the situation you are in: Run, Hide or Fight.
For more information about each option and links to resources, see the full memo.
AnnouncementsNew Lab Director to Visit Feb. 21-23
Stuart Henderson, who becomes the lab director on April 3, will be visiting Jefferson Lab Feb. 21-23 to continue his orientation process. During this visit, he will meet with lab leadership to receive overview briefings on lab organization and functions. An additional short visit to the lab is anticipated in March.
JAG Seeks Design Ideas for 2017 JLab T-shirt Contest
The Jefferson Lab Activities Group is seeking entries for the annual T-shirt design contest. Your idea could become the winning design for Jefferson Lab's 2017 T-shirt! New ideas and previously submitted designs are welcome. The winning design will be unveiled at the lab's annual Run-A-Round event, scheduled for May 17. Submit your design online via the JAG webpage by close of business on Friday, March 17. Design requirements and more information may be found in the memo.
Golf League Forming for 2017 Season; Interested Golfers to Meet on Feb. 23
The Jefferson Lab Golf League is open to all current staff, retirees, users and their spouses. All levels of play and weekly availability are welcomed. A 2017 organizational meeting will be held on Thursday, Feb. 23, in CEBAF Center, Room F113, noon-1:00 p.m. No food will be served at the meeting, but attendees are welcome to bring their lunch or purchase something from the cafeteria. For more information, see the full notice.
Jefferson Lab Benefits Open Enrollment Ends Feb. 28
Attention all regular and term employees: The 2017 Benefits Open Enrollment ends Feb. 28. This is the time of the season for you to review and, if necessary, modify your benefits options. For more information and links, see the memo.
Reminder: Annual Property Training & Validation Due March 31
Jefferson Lab’s annual Property Custodian Training and Property Validation for 2017 was launched on Feb. 1 and continues through Friday, March 31. It is important for everyone to complete the training and validation during this period to allow Property Management to conduct the sample inventory required under our Department of Energy contract. See the full memo for links to the training and validation. If you have property or property validation process questions or concerns, contact the Property office at x7348 or email@example.com.
Jefferson Lab Calendar of EventsFeb. 24-25: Q-Weak Collaboration Meeting
March 4: Va. Regional Middle School Science Bowl
March 15-17: 3D Nucleon Tomography Workshop
March 17: Workshop on Science at LERF
March 28-31: CLAS Collaboration meeting
|JLab Weekly Briefs is an ongoing publication providing information on the status of safety, accelerator operations, experiments, free-electron laser, reviews, upcoming activities and special events. Deadline for submission is every Tuesday by 10 a.m. Submit new items to: the Communications Office or contact Kandice Carter at x7263.|