Jefferson Lab Weekly Briefs
May 27, 2009
12 GeV Upgrade
The Central Helium Liquefier (CHL) Building Addition contractor is installing the electrical ductbanks under the floor slab. These electrical ductbanks are concrete-encased conduits to provide 4160V and 480V power and control wiring to the CHL#2 compressors. The compressors and wiring will be installed by the JLab Cryogenics Group following the Building Addition construction. The CHL#1 cooling towers are slated for replacement as part of ongoing infrastructure work. The 12 GeV, Facilities and Cryogenics Groups are reviewing the feasibility of combining the CHL#1 and #2 cooling towers to provide lower life-cycle costs.
With the receipt of the land disturbance permit from the City of Newport News, the Hall D construction contractor mobilized and started clearing trees. The undeveloped road adjacent to the Residence Facility will be used for access until the construction entrance off the public access road, Canon Boulevard, is built. A revised Traffic Signal Plan for the construction entrance has been submitted to the City of Newport News for approval.
The accelerator was running well with low trip rates. The day shift on May 19 was spent on beam studies. The insulating vacuum pump of zone 1L06 failed, and the faulty pump was replaced. On Thursday, the wafer of gun2 was reactivated to boost the quantum efficiency, and some radiofrequency (RF) cavities were recovered. There were no major issues during the holiday weekend.
Free-Electron Laser (FEL)
The contract for the FEL ultraviolet effort with the Air Force Research Laboratory was signed this week. That allowed FEL staffers to install the final bend chamber and to place it under vacuum. The low-conductivity water cooling line is expected to be completed after several delays due to rain interference. A pressure test was planned for Tuesday.
A new Theory Center paper <arXiv:0905.4120 [hep-lat]> calculates bottom-hadron masses using lattice QCD with 2+1 flavors of dynamical quarks in the static limit for the bottom quark. The result for the mass of the recently discovered Ωb is consistent with the recent CDF measurement at Fermilab and in disagreement with the previously reported D0 result. The mass for the as-yet-unobserved Ξb particle is also predicted to be 5955(27) MeV.
JLab's Safety Numbers
142 Days since Last Recordable Accident (JLab record: 331)
JLab Calendar of Events
May 28: Safety Shoe Vender onsite
Summer Education Calendar
Environment, Safety, Health & Quality
Hurricane season runs from June 1 to November 30. There are multiple things you can do to safeguard your home and family, some of which are listed on the Virginia Department of Emergency Website. Additionally, Virginia has established a Hurricane Preparedness Sales Tax Holiday from May 25 to May 31. Some of the items that may be purchased exempt of the Retail Sales and Use Tax are listed here.
Jefferson Lab's policy on hurricane preparation and decision making is listed in Chapter 3510 of the ES&H Manual and contains guidelines on responsibilities, media outlets for employee notification, adjustment of operating hours and recovery after the event.
Computing and Networking Infrastructure
IT Helpdesk Summer Hours
Timely Timesheets Aid Salary Adjustment Process
Watch for Construction Traffic Entering/Exiting JLab
JLab Walking Trail Changes to Stay Out of Construction Area
Virginia’s Hurricane Preparedness Sales Tax Holiday