Jefferson Lab Weekly Briefs August 13, 2014
Jefferson Lab Weekly Briefs
August 13, 2014
12 GeV Upgrade
Work on the voltage-tracking regulators for the extraction YA’s remains on hold, awaiting restoration of power to the service building. The current transducer for the Hall D leg of the beam envelope limit system has been received. The magnets for the fast-feedback system for the Hall D beamline have been completed. The cavities for the nanoAmp beam position monitor system for the Hall D beamline are being welded and will then be sent out for plating.
Center for Theoretical and Computational Physics
A new paper by researchers in the Theory Center and Indiana University presents a new global QCD analysis of parton distribution functions, allowing for possible intrinsic charm (IC) contributions in the nucleon, which cannot be generated by perturbative gluon radiation alone. The analysis makes use of the full range of available high energy scattering data for Q2 > 1 GeV2 and W2 > 3.5 GeV2, including proton and deuteron cross sections from SLAC that were excluded in earlier global analyses. The combined data place more stringent constraints on the momentum carried by IC than previously reported, with x> IC < 0.1% at the 5-sigma level.
Maintenance work on the Central Helium Liquefier-1 carbon bed and nitrogen heat exchanger was completed. Cryogenics group personnel are in the final phases of cleaning up the system and preparing it for restart and cooldown. The CHL2 plant operated at 4 Kelvin through the summer, maintaining liquid levels in both linacs. The control systems for the CHL1 gas management and the SCN 2 Kelvin cold box were upgraded from CAMAC to PLC using hardware purchased using AIP funds.
The Cryogenics Test Facility plant recently went through a two-week shutdown and warmup for maintenance. It has been restarted and is currently supporting Vertical Test Area and Cryomodule Test Facility activities.
The End Station Refrigerator was shut down to support power work at the end stations. The halls are maintaining many of their magnets at 80 Kelvin. The ESR is expected to be restarted around mid-September.
The Hall D cold box repairs and modifications were completed. The cold box was reinstalled, recommissioned and load tested in liquefaction and refrigeration modes. The Hall D solenoid was successfully cooled and filled using the refurbished cryogenics plant, taking a little over three weeks to complete the process. The magnet has been full of liquid helium for almost two weeks while the extensive pre-power checklists have been completed. To date, the magnet has circulated up to 15 amps.
Facilities Management and Logistics
Hogan Drive Paving Scheduled for Saturday, Aug. 16
Lab staff and users who wish to be onsite on Saturday are encouraged to use the Lawrence Drive entrance via Jefferson Ave. A map of the Jefferson Lab site can be found at the link.
CEBAF Center A & C Wing Restrooms to Close Temporarily for Refurbishment
Phase I includes Wing A restrooms on the first and second floor.
Phase I work is set to begin on Monday, Aug. 11, and should be completed within four weeks. Phase II work is planned to begin immediately thereafter and should take about the same time. Notification will be made in advance of the start date for Phase II.
Notices will be placed on the restroom doors while they are closed. The notices will include locations of other restrooms. The anticipated project completion date for all phases is late September. Facilities Management appreciates your patience during this brief inconvenience, as we work to provide safe, sanitary and upgraded restrooms.
Environment, Safety, Health and Quality
Normalization of Deviations
So, what has started out as a deviation from normal has become accepted. People are desensitized to the abnormal. This process is the Normalization of Deviations. We need to step back and think: "Is what I'm doing or seeing really proper?" If not, take action before you are the one injured.
Computing and Networking Infrastructure
Central Computing Outages Set for Saturday, Aug. 16
CNI Maintenance Period Set for Tuesday, Aug. 19, 5-7 p.m.
Cybersecurity: Protect Against USB Vulnerability
For more tips on safely using USBs, see these recommendations from the U.S. Computer Emergency Readiness Team.
Jefferson Lab Employee Tour Set for Thursday, Aug. 28
Registration Underway for Sept. 12 United Way Day of Caring
Red Cross Blood Drive Set for Aug. 19
Home Welders: Welding Torch Handle Recall
Jefferson Lab Calendar of Events
|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.|