• Wed, 05/20/2015 - 3:37pm

    Jefferson Lab Weekly Briefs
    May 20, 2015

    12 GeV Upgrade

    Hall C: Connection of the Hall C SHMS Horizontal Bend (HB) magnet to all of its services was completed and the magnet was successfully cooled-down to liquid-helium temperature (4.2K).  A challenging aspect of this magnet is that the distance between helium-temperature and room-temperature pieces is only a few millimeters in some places.  The successful cool-down shows that this challenge has been met.  During initial tests, the magnet was operated successfully at 10 percent of its eventual operating current. Careful engineering studies are being performed in preparation for full-current testing.  The vendor building the Q2, Q3, and Dipole magnets is half-way through a series of practice tests that will conclude with shrinking the large metal collars onto the dipole magnet coils.

    The new support system for the massive steel yoke of the SHMS Q2 magnet has been installed, and progress has been made towards completion of the gas system of the Heavy Gas Cerenkov detector.  Installation of the large number of signal and high-voltage cables for all of the SHMS detectors continues.

    Physics

    Hall B: The Heavy Photon Search (HPS) Experiment in Hall B completed its Engineering Run on May 18, the last day of the extended Spring CEBAF running schedule. Working nights and weekends while CLAS12 construction proceeded during the week days, HPS was able to complete detector installation and fully commission its beamline, electromagnetic calorimeter, trigger, data acquisition system, and silicon tracker. Beginning in early May, HPS took its first physics data, including 1/3 of a PAC week in its design configuration, where its silicon microstrip detectors are a mere 500 um above and below the beam. Thanks to the tiny, stable CEBAF beams and lack of beam halo, this worked perfectly. HPS is searching for signs of a massive cousin to the photon which decays to electron/positron pairs and may couple to the dark matter.   

    Published Journal Articles, May 11-15, 2015
    Diana Parno, David Flay, Matthew Posik (The Jefferson Lab Hall A Collaboration). "Precision Measurements of A1n in the Deep Inelastic Regime."   Phys.Lett.B,744, 309-314. (2015)
    http://dx.doi.org/10.1016/j.physletb.2015.03.067

    Kondo Gnanvo, et. al.  "Large size GEM for Super Bigbite Spectrometer (SBS) polarimeter for Hall A 12 GeV program at JLab."  Nucl.Instrum.Meth.A 782, 71-86 (2015).
     http://dx.doi.org/10.1016/j.nima.2015.02.017

    K. Chirapatpimol et al. (Hall A Collaboration).  "A precision measurement of the p(e,e'p)π0 reaction at threshold."  Phys. Rev. Lett. 114, 192503 (2015)  
    http://dx.doi.org/10.1103/PhysRevLett.114.192503

    Nicholas Zachariou, et. al  (CLAS Collaboration).  "Determination of the Beam-Spin Asymmetry of Deuteron Photodisintegration in the Energy Region Eγ=1.1-2.3 GeV."  Phys. Rev. C 91, 055202 (2015).
    http://dx.doi.org/10.1103/PhysRevC.91.055202

    Tech notes:
    JLAB-TN-15-014.  Dustin Keller.  "Systematics of small spin-1 tensor asymmetries with a solid polarized target."
    https://jlabdoc/docushare/dsweb/Get/Document-101909/15-014.pdf

    Center for Theoretical and Computational Physics

    The spin-dependent cross sections for semi-inclusive lepton-nucleon scattering have been derived within the framework of collinear factorization, including the effects of masses of the target and produced hadron at finite momentum transfer. At leading order in strong coupling, the cross sections factorize into products of parton distribution and fragmentation functions evaluated in terms of new, mass-dependent scaling variables. The size of the hadron mass corrections is estimated at kinematics relevant for future semi-inclusive deep-inelastic scattering experiments at Jefferson Lab.

    Engineering

    The Electrical Engineering Systems (EES) department has been busy the last couple weeks supporting the end of the Accelerator beam operations and preparing for the start of the summer shutdown. The shutdown began Monday, May 18. The major activities in the coming weeks will be preventive maintenance work on RF systems, magnet power and instrumentation and controls hardware. Safety system recertification will follow maintenance and upgrades on the personnel safety system. Other major tasks include:
       - new Dogleg Power Supply installation for 12 GeV operations;
       - F100 cryomodule commissioning support in the LERF (formerly the FEL);
       - RF separator improvements;
       - support for helium processing of RF cavities;
       - procurements of hardware for the Injector Test Stand facility in the Test Lab;
       - and many minor system upgrades geared towards improved reliability.

    Work continues on tasks associated with the lab’s collaboration on the LCLS II project for SLAC. EES personnel are working on RF system design and RF controls hardware for that project.

    Environment, Safety, Health and Quality

    Personal Protective Equipment (PPE): The last mitigation to an electrical hazard
    Electrical injuries/fatalities (resulting from an electrical shock or an electrical arc flash) are ranked high in the workplace accident categories by OSHA (Occupational Safety & Health Administration).
    As we all know, the safest way for working around electricity is by shutting it off completely and executing a proper lockout/tagout. There are times though when electrical systems need to stay energized while being worked on; in these scenarios other safe work practices need to be developed to mitigate the electrical hazards down to the lowest possible level.
    When PPE (Personal Protective Equipment) is introduced as mitigation, it should be considered the last defense against an electrical hazard. Some simple rules to remember when donning electrical PPE are as follows: 

    • Makes sure that the PPE is correct for the application (voltage & arc flash levels),
    • PPE is in good condition and cared for per the manufacturer’s guidelines,
    • PPE has been tested per industry standards and best practices, and

    PPE is properly worn and sized for the worker.

    Announcements

    Festival Volunteers Needed Saturday, May 30, and Sunday, May 31, Jefferson Lab Public Affairs requests your help staffing its outreach tent at the Hampton Blackbeard Pirate Festival. Through the new festival program, we hope to spread awareness in Hampton Roads about JLab's work and its role in the national lab system. You'll help by assisting with children's activities, talking about the lab and handing out information. On each of the two days, Public Affairs will need volunteer help in four-hour blocks: from 10 a.m. to 2 p.m., and from 2 p.m. to 6 p.m. If you can join us, please e-mail Mike Robbins at mrobbins@jlab.org or call x7617.

    Lab-wide Annual Property Inventory Will Take Place June 1 – July 31
    The laboratory’s annual property inventory will start the week of June 1 and run through July 31, 2015. The property manager has randomly selected 20 percent of Jefferson Lab's property custodians for this year's property inventory. Those custodians will be contacted by a member of the property staff.
    In addition, any custodians that did not complete their annual property validation will also be included in the inventory group for this year. As of May 19, seventy-one individuals still needed to complete their property validation and 175 staff and Users still needed to complete their key validation.
    To complete the inventory, each item must be physically seen by a member of the property office. Note that the property custodian is responsible to know and search if needed for their assigned property, not the property staff.  Property staff will go to the location identified for each item during the property validation to inventory the property. The assigned custodian will be notified of any item not located at its specified location, and the item will be reported as "missing" until the item is physically located by the custodian and verified by property staff. 
    If you have questions regarding property validation or the inventory, contact Christian Whalen at x5899 or ctwhalen@jlab.org.  For questions regarding key validations, contact Dennis Merritt at x7963 or merritt@jlab.org.

    Travelers and Travel Coordinators: Remember Expense Report Deadlines
    The timely receipt of travel expense reports continues to be a finding on the Internal Audit reviews.  Just a reminder, Jefferson Lab travel policy deadlines for expense reports are:
    - Domestic travel: submit expense report within 10 calendar days of return, and
    - Foreign travel: submit expense report within 20 calendar days of return. 
    As always, your support of this lab policy is appreciated.  Contact Carol Kinsey at
    kinsey@jlab.org or x7519 with any issue that keeps you from meeting the policy or if you have any questions.

    JLab Implements Process to Improve Public Access to Research Results
    In October 2014, the Department of Energy began implementing its Public Access Plan across the DOE complex. This requirement stems from a Feb. 22, 2013 memorandum titled, "Increasing Access to the Results of Federally Funded Scientific Research," in which John Holdren, director of the White House Office of Science and Technology Policy (OSTP), directed federal agencies to develop and implement plans for increasing public access to the full-text versions of final, peer-reviewed publications and digital research data resulting from agency funded research.

    Public Access, or Open-Access (OA) literature is digital, online, free of charge, and free of most copyright and licensing restrictions to readers, according to Kim Edwards, Jefferson Lab’s publications manager and a certified records manager in the Information Resources section. All authors of lab research results are asked to follow this process, which is posted online at: https://www.jlab.org/memo/jlab-implements-process-improve-public-access-research-results

     

    Jefferson Lab Calendar of Events
    May 25: Memorial Day holiday - Jefferson Lab closed
    May 26-30: QCD Evolution 2015 Workshop
    May 26-July 31: SULI and REU undergraduate internships at JLab
    May 27-29: QWeak Collaboration meeting
    June 1-3: Jefferson Lab annual Users Group meeting
    June 1-19: Hampton University Graduate Studies (HUGS) at JLab

    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: Public Affairs or contact Kandice Carter at x7263.