Jefferson Lab Weekly Briefs
October 31, 2012
12 GeV UpgradeGreat progress continues in Hall D. The vendor for the tagger magnet has completed epoxy-potting and testing the 12 coil packs and plans to ship by the end of the year. The large valve box that distributes helium and nitrogen to the solenoid magnet has been installed, and the lengthy process of adding superinsulation and connecting the hundreds of instrumentation wires has begun. The start of magnet cooldown is planned for December.
Many institutions are contributing to the detector systems in Hall D. The first batches of light guides for the Hall D barrel calorimeter have arrived from the University of Santa Maria in Chile. The silicon photomultipliers have been manufactured and will be mounted on the light guides. The first shipment of a related light-monitoring system has arrived from the University of Athens. Indiana University is checking the final photomultiplier tubes for the lead glass forward calorimeter. The central drift chamber is having the last electronics hook-ups added at Carnegie Mellon University. About half of the FADC-250 modules for reading out the two calorimeters are being tested at the University of Massachusetts. The FADC-125 modules needed for the drift chambers have begun fabrication, as have the F1TDC modules. Finally, Florida State University has begun work on the time-of-flight wall located just upstream of the lead-glass calorimeter.
Free-Electron LaserThe FEL team has scaled back activities to stretch funding until the FY13 supplement arrives. The team continues to make progress on the load-lock system and ring resonator cavity. The U-tubes on the FEL cryomodules, which were already warm, were pulled for vacuum work.
Center for Theoretical and Computational PhysicsA new Theory Center analysis builds an effective theory for baryons, combining the 1/Nc and chiral expansions of QCD, and analyzes baryon masses and axial currents in this framework. By analyzing lattice QCD results from the Lattice Hadron Physics Collaboration at JLab, among others, the study demonstrates the important role played by SU(4) spin-flavor symmetry in the baryon sector (which emerges in the large-Nc limit of QCD) in the physical world with Nc=3. In particular, large-Nc requirements are found to imply necessary cancellations between Feynman diagrams that result in a mild dependence of the nucleon axial coupling on the light quark masses.
EngineeringElectrical Engineering Department activities have centered on 12 GeV installation tasks. Radiofrequency system installation has resumed in earnest with the start of FY13. Work has been focused on zone NL22, as well as the other four zones in the North Linac. Magnet power trim rack and shunt rack installation is in progress in the other service buildings.
Tunnel installation activities include cable pulls for new equipment and cable tray installation in the Hall D tunnel extension at the end of the North Linac. The Safety System group is busy with Oxygen Deficiency Hazard system and Personnel Safety System cable installation for Hall D and the tagger area. The Instrumentation group worked on magnet power communication, vacuum, and harps and viewer installation. Conversion to new controls for the R100 cryomodule installation in 0L04 is in progress. Characterization of the 12 GeV stripline beam position monitors was also completed.
JLab Calendar of EventsNov. 5-8: TESLA Technology Collaboration (TTC) Meeting
Nov. 13: Science Series: The Origin of the Elements
Nov. 15-17: CTEQ Collaboration Meeting
Nov. 19: Safety Shoe vendor onsite
Nov. 20: Colloquium and Public Lecture
Nov. 22-23: Thanksgiving holiday; JLab closed
Environment, Safety, Health and QualityDo you rely on your local Safety Warden?
Safety Wardens conduct periodic checks of safety-related equipment, such as emergency showers, eyewash stations, emergency lights and exit signs. They also keep an eye on the ever-changing conditions and equipment in their areas of responsibility, and they are assigned to help answer questions or direct workers to the correct ESH&Q professional who can get needed information.
However, Safety Wardens won't always be the first to know when something breaks. During the course of your work day, you may see something amiss or an item in need of attention. If you do, take action to get it done. If the situation or item is safety-related, inform your local Safety Warden, and then do your part to resolve the situation for the safety of you and your co-workers.
Last Chance to Name That Cryomodule!
JAG Oktoberfest Event Results