Jefferson Lab Weekly Briefs
November 12, 2015
12 GeV Upgrade
Cosmic ray tests of the Silicon Vertex Tracker for CLAS12 have been ongoing since September, and the events recorded have been used to test track-reconstruction routines for the SVT, as well as establish correct readout, good noise performance, and full response for the entire detector. The High Threshold Cerenkov Counter has been completed and is undergoing testing as it awaits installation in Hall B. This includes monitoring of the relative humidity inside the gas volume, which is a key parameter for maintaining good optical behavior of the large mirror. The construction of the upstream support structure for the Central Time of Flight has been completed, as has fabrication of most parts for its light monitoring system and its transport crate. Refurbishment of the fourth and fifth of the six sectors of the Low Threshold Cerenkov Counter is well advanced. The sealing of the new LTCC window has been demonstrated on the first three boxes and tested successfully on the first box with actual counter gas. An order has been placed for the remaining fast electronic modules, the Crate Trigger Processors, needed to complete the DAQ and triggering systems for Hall B. Work is underway for the slow controls needed to operate all elements of CLAS12. Finally, the work to upgrade beamline elements has started.
Jefferson Lab Published Journal Articles, Nov. 2-6
Remember to submit your papers for approval to the Jefferson Lab Publications database.
Center for Theoretical and Computational Physics
A new approach has been developed for describing the transverse momentum dependence of observables in hard exclusive processes, such as the photon-pion transition form factor and the pion electromagnetic form factor. Its basic ingredients are functions describing the distribution of pion constituents in virtuality and transverse momentum. Simple models for the soft part of these functions were used for comparison with experimental data (from BaBar and Belle) on the pion transition form factor. The paper also shows how one can generate high transverse momentum tails from initially soft distributions.
The Electrical Engineering group has been working two fronts in recent weeks: restoring the Low Energy Recirculator Facility (LERF) back to operational status and performing hot checkout on CEBAF. DC Power has been running all magnet systems at full 12 GeV settings, which has also had the further effect of warming the tunnel, providing the 'load' for the newly installed tunnel air conditioning system. The group has also successfully completed preliminary tests on one of the Hall B superconducting power supplies to 3,800 Amps.
The RF group has had its share of challenges recently, working constantly to provide the RF power for the gradients required for 12 GeV running. The group has been supporting the collection of RF trip rate data that has been taking place over the past two weeks.
The I&C group inherited many non-functional systems at the LERF, which they had to troubleshoot and repair. These systems were often unique to that machine and required a lot of effort to get up and running in a short space of time. While the group was completing these tasks, group members were also working to complete hot checkout in the CEBAF accelerator.
The Safety Systems group also had new systems to support at the LERF, meanwhile making sure that the personnel and machine safety of CEBAF was not compromised in any way. The Electrical Support group, as well as supporting the other EES groups, has also been working in Hall B with the Torus and Solenoid instrumentation and control efforts. This has been a very busy and productive start to the fiscal year for EES and will likely continue to be.
Facilities Management and Logistics
Construction Near Lawrence Drive and the Walking Trail
The walking trail is now closed to pedestrian traffic, as it is in the path of the construction. FM&L will evaluate the condition of the trail and advise the Jefferson Lab community on its status once the construction project is complete. If you have any questions or concerns about this work, contact Bob Sperlazza, x6241.
Environment, Safety, Health & Quality
Cold Weather Alerts
If you haven't already taken a couple of minutes to prepare for winter working conditions, make the effort now to brush up on cold stress indicators by reading the ES&H Safety Manual Chapter 6670 Heat and Cold Stress Mitigation Program. Remember that a person's medications and overall health may make them more susceptible to the effects of the colder temperatures. If an employee appears to be adversely affected by the weather, get them inside a building or to Occupational Medicine.
Computing and Networking Infrastructure
IT Maintenance Day Set for Tuesday, Nov. 17, 5-8 p.m.
CEBAF Center's F Wing Closed on Saturday, Nov. 14, During Electrical Work
Thanksgiving Buffet in the Quark Café
Order a Quark Cafe Dessert for Your Holiday Celebration
Applications Due for Summer Student Internships at Jefferson Lab
Inventors & Entrepreneurs: Sign up Now for START! Peninsula 4.0 Event Nov. 13-15
Jefferson Lab Calendar of Events
Nov. 16-17: Q-weak Collaboration Meeting
|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.