Jefferson Lab Weekly Briefs
August 24, 2011
12 GeV Upgrade
Stacking of lead sheets and scintillator bars threaded with wavelength-shifting fibers is complete for the first sector of the preshower calorimeter for CLAS12. The third wire chamber sector for Region 2 is underway at Old Dominion University, the first Region 1 sector is nearing completion of field wire stringing at JLab, and the clean room for the remaining Region 1 sectors is built at Idaho State University. The first production scintillators and photomultiplier tubes for the CLAS12 forward time-of-flight detector have arrived and are being assembled at the University of South Carolina. The first half-dozen mirror cores are built for the high-threshold Cerenkov counter and machining for the molds for the next of the four mirror types has started. The first silicon sensors, of all three types needed, for the silicon vertex tracker (SVT) barrel have arrived and are being tested. First articles of the SVT electronics have been tested and shown to give very good signal/noise performance.
Hall A installation of the g2p experiment is continuing.
In the injector, the Polarized Electrons for Polarized Positrons (PEPPo) experiment cable tray and conduit have been installed. In the south linac, installation of C100 cryomodules in zones 2L23 and 2L24 continues. The C100 cryomodule at 2L24 has been cooled down and commissioning has started. In the west arc, vacuum installation and remnant field readings have been completed. Core drilling is taking place at the tunnel roof for two new penetrations. The low-conductivity water system installation for the north and south linac box supplies has completed, and other LCW repairs are in progress. Magnet shim inspections and repair and beam switchyard "inside building" steel erection are all projects in progress. Lastly, functional checks of the End Station Refrigerator in progress.
Processing of the gun was completed, and assembly of the injector beamline components is commencing. The FEL team hopes to get the system in a state capable of supporting beam by late next week. Testing of magnet power supplies and other beamline components continues in the rest of the linac.
Center for Theoretical and Computational Physics
A comprehensive new report summarizes the outcome of a 10-week program on "Gluons and the quark sea at high energies: distributions, polarization, tomography," which took place at the Institute for Nuclear Theory in the fall of 2010. The principal aim of the program was to develop and sharpen the science case for an Electron-Ion Collider (EIC), a facility that will be able to collide electrons and positrons with polarized protons and with light to heavy nuclei at high energies, offering unprecedented possibilities for in-depth studies of quantum chromodynamics. The report reviews, in detail, the scientific opportunities presented by an EIC, and identifies "golden experiments" with the greatest discovery potential in four major areas of investigation: the spin and flavor structure of the proton; three-dimensional structure of nucleons and nuclei in momentum and configuration space; QCD matter in nuclei; and electroweak physics and the search for physics beyond the Standard Model.
The cryogenics group has just completed testing the fourth coil (of four) of the Hall D superconducting solenoid magnet. This completes the test program. The next phase will be a simultaneous test of all four coils in Hall D.
The magnet measurement group completed the rework and measurements of the accelerator arc magnets for the Six Month Shutdown. In all, 208 dipole magnets were refurbished and many of the arc 10 four-meter dipoles were installed. Quality assurance and measurement work has now begun on the new 12 GeV dipole magnets. as well as measurements of several magnets to support the PEPPO experiment.
Environment, Safety, Health and Quality
Don't Try to Reason with Hurricane Season
As important as it is to be prepared for a weather emergency, it's just as important to be informed on the steps to take for recovery. The Virginia Department of Emergency Management offers a webpage filled with information on what to do after disaster strikes.
Computing and Networking Infrastructure
Call Data Reporting Feature Now Available
South Connector Road Re-Opens
United Way School Tools Drive Ends Tomorrow
Come and Get It! Decade of Jefferson Lab Physics Published
Recent Additions to JLab Lost & Found
Tracking Thomas at JLab
Congratulations to Stephen Smith, Russell Mammei and Susan Brown, who were the first to correctly identify the Aug. 17 location. Honorable mentions go to Sasa Radovic, Kelly Tremblay, Percy Harrell, Jason Willoughby, Doug Higinbotham, Jim Follkie, Michelle Shinn, Rebecca Yasky, Casey Heck, Mike Koch, Elaine Zuchowicz, Mike Martin, Sam Holben, Bonnie Madre and Mike Davis. 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