Jefferson Lab Weekly Briefs
July 6, 2011
PhysicsIn Hall A, the installation for the upcoming run period is proceeding. The spectrometers were surveyed and various stands and platforms were installed. Work progressed on the cryogenic system, the water system and the power supplies. In general, the work is ahead of schedule. A Hall A staff position is open and is being advertised. AcceleratorIt was another productive week for the scheduled accelerator down. The injector experiment (PEPPo) installation is almost complete. West arc magnet installation and alignment continues to move along rather nicely. In the east arc, removal of the magnet cooling water hoses, power leads and beam tubes continues, enabling the start of removal of the magnets from arcs 7 and 9. In the injector, a faulty fiber-optic cable for the beam sync signal was found and repaired. Over the weekend, a pump for the cooling water pipe trench failed, allowing rain water to enter the west arc. This slowly spread until a layer of water was around the arc and into the north linac. On Tuesday morning, a portable pump was used to move the water to a drainage sump for removal. Free-Electron LaserFEL staffers have begun the bake on the high-voltage DC gun, and the vacuum appears to be progressing well. The group has one component left to install on the injector beamline before it will be ready for bake. The valve replacements on the booster were completed and the unit is expected to be cooled to 4 Kelvin next week. Mirror replacement work in the infrared system is also progressing. Center for Theoretical and Computational PhysicsA new paper <arXiv:1106.5515> interprets lattice QCD results for the meson spectrum in terms of 'conventional' quark-antiquark bound states, supplemented by a spectrum of hybrid mesons in which an excited gluonic field plays an essential role. For the first time in a QCD-based calculation, the paper clearly identifies the lightest supermultiplet of hybrid mesons having J{PC} quantum numbers of (0,1,2){-+} and 1{--} and proposes that a gluonic field of chromomagnetic character is the lowest energy excitation. Existing models of hybrid mesons are considered critically and steps toward a QCD-based phenomenology of hybrid mesons are outlined, relevant for the searches being made now at COMPASS and in future Jefferson Lab experiments.
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Environment, Safety, Health and QualityWith the many deliveries made onsite daily and the many large construction vehicles onsite, it's important to be especially careful when driving and walking around delivery or construction vehicles. These vehicles are particularly dangerous when they are engaged in backing up. While backing, the driver can only look in one mirror at a time and would not see a person moving quickly from the other side of the truck. Sometimes the driver may have a spotter to assist in properly aligning the vehicle while backing, but these spotters may also have a difficult time seeing pedestrians or other vehicles. Announcements Temporary Water Shutoff Today After Work for CEBAF Center, Test Lab & ARC Quarterly Publications Training Offered July 12 Email Vacation Utility and Phone Vacation Greetings Reminder Lunchtime Seminar on July 19 for Managing Stress in the Workplace Tracking Thomas at JLab Congratulations to Val James and Michael Haddox-Schatz, who were the first people to correctly identify the June 29 location. Honorable mentions go out to Jason Willoughby, Narciso Gomez, Michelle Shinn, Dick Owen and David Anderson. 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 July 11: Safety Shoe vendor onsite |