Jefferson Lab Weekly Briefs
July 8, 2015
12 GeV UpgradeThe construction of the four regions of the Silicon Vertex Tracker (SVT) for CLAS12 has been successfully completed. The first three regions are operating as one unit in the Experimental Equipment Lab Rm 124 clean room, and the fourth is operating separately. The remaining step will be to rotate both units to a horizontal position and check their fit as one integrated tracker, after which the SVT will await installation into CLAS12 in late 2016. The High Threshold Cerenkov Counter has completed alignment of all the photomultiplier tube (PMT) mounts and is undergoing addition of the covers and access plates for its containment vessel. The next steps include re-installation of the main mirror and the addition of gas windows. The construction of the 48 counters of the Central Time-of-Flight detector is complete, and the custom three-layer magnetic shields do indeed work as predicted in the gradient fields that will be encountered outside the solenoid magnet at the PMT positions. Refurbishment of the first of the six sectors of the Low Threshold Cerenkov Counter (LTCC) is finished. This has included re-covering the mirrors with aluminized Lexan strips, coating the PMTs with p-Terphenyl, and re-coating the Winston Cones to improve ultraviolet response and overall photon statistics to aid in the LTCC’s new role as a tagging Cerenkov for pions in CLAS12.
Center for Theoretical and Computational PhysicsThe possibility that QCD Hamiltonian matrix elements between physical states can be approximated with "lattice-improved" tree diagrams has been explored in a new paper. Results for the coordinate space lattice gluon correlation functions are presented and applied in the computation of the static quark potential. This example illustrates the possible emergence of constituent gluons.
Facilities Management and LogisticsDemolition/Construction to Close Parking Areas Near Accelerator Site Entrance
Demolition of the two Radiation Control Department trailers and Building 52 is expected to begin on July 13 and will take about one month. The parking area around these buildings will be closed beginning the evening of July 10 and will remain closed until construction of the new EHS&Q building on the same site is complete in 2016. A sketch showing the area to be blocked can be found on the linked all-staff memo.
All personnel are reminded to stay out of this area. If you have any questions about this project, contact Suresh Chandra at x7248.
Jefferson Lab Calendar of EventsJuly 3: Independence Day holiday observed; Jefferson Lab closed
July 7-10: Program Advisory Committee Meeting (PAC43)
July 15-16: Super BigBite Spectrometer Collaboration Meeting
July 17-18: Hall A/C Summer Collaboration Meeting
July 20: Safety Shoe vendor onsite
Aug. 18: American Red Cross Blood Drive
Aug. 19-21: Q-weak Collaboration Meeting
Sept. 7: Labor Day holiday; Jefferson Lab closed
Environment, Safety, Health & Quality
Summer Brings out Local Wildlife and Insects
• Inspect dark or concealed areas with a flashlight; avoid using your hand to check for spiders, snakes, or other pests. Be extra careful around all pipes and under the gas-flow handles on gas-storage bottles and overhanging eaves on buildings – use appropriate repellents and/or stay away from paper wasps that are known to make nests in these locations;
Tornado Warning Siren Test Set for Friday, July 10
Jefferson Lab Employee Tour Set for Thursday, Aug. 27
Looking for Summer Fun? Discount Entertainment Tickets Available
|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.|