Jefferson Lab Weekly Briefs
March 26, 2008
12 GeV Upgrade
Design effort on the conventional facilities to support the 12 GeV CEBAF Upgrade continues to progress. The 100 percent design package for the North and South Access utility upgrades was completed by the JLab Facilities Design Team. This project expands the low-conductivity water (LCW) systems for the linac service buildings and the arc magnets and adds electrical substations to increase the power capacity at each building. The design package has been distributed for an internal design and safety review.
The JLab Procurement group has posted the Sources Sought notice for construction contractors interested in the Hall D Complex. This will be a best-value procurement, which evaluates a vendor's capability in addition to the price as part of the selection process.
A Change Request has been approved authorizing three additional R&D tasks for the Upgrade cryomodules: (1) precise re-measurement of the damping of higher-order modes in two 12 GeV cavities in the Horizontal Test Bed (HTB), (2) repeat of those measurements in the Vertical Test Area (VTA) to vet a new step in the cryomodule quality assurance process, and (3) explore alternate thermal strapping strategies for the cavity endgroups for potential cost savings.
Hall B is in the final preparations for the startup of the g12 run group. This run group will search for unusual hadronic matter, such as mesons with quantum numbers that cannot be produced with a quark/anti-quark pair. These mesons are candidates for so-called "hybrid" mesons, representing gluonic excitations.
This week was marked by the windup of Scheduled Accelerator Down (SAD) activities and the startup of threading beam around the machine in preparation for resuming beam operations to the experimental halls on April 1.
Free-Electron Laser (FEL)
FEL staff continued preparations toward producing 1 nanoCoulomb (nC) bunches in the gun test stand (GTS) by optimizing drive laser performance and revisiting the PARMELA modeling to account for the final configuration. The team is working to produce and measure the nC bunches as this is being written. The FEL gun is repairing some insulators which appear to be conducting excessively. FEL staff also finished mapping the last sextupole and received a new ultra-sensitive terahertz (THz) detector for that lab.
Understanding the true nature of excited nucleon states may be most easily gained by studying its structure and form factors. Recent results by the CLAS collaboration show interesting behavior in the Q2 dependence of the nucleon-Roper transition. In a new Theory Center paper, arXiv:0803.3020 [hep-lat], the first ever model-independent calculation of the nucleon-Roper transition form factor has been performing using lattice QCD, which explored this transition for Q2 up to 3 GeV2.
JLab's Safety Numbers
189 Days since Last Recordable Accident (JLab record: 319)
Environment, Safety, Health & Quality
One influenza virus has emerged recently as the predominant virus for the season. This virus is not included in the current 2007-08 U.S. vaccine, so even those who have been vaccinated are highly susceptible. According to the Centers for Disease Control (CDC), 44 states report widespread flu activity; five states report regional activity; and one state and the District of Columbia report local activity. Flu viruses spread mainly from person to person through coughing or sneezing. Healthy adults are able to infect others beginning one day before symptoms develop and up to five days after becoming sick. That means that you may be able to pass the flu on to someone else before you know you are sick, as well as while you are sick. The flu season is expected to continue through May. The CDC suggest the following precautions:
JLab Finger Injury Lesson Learned
The injury investigation noted the following lessons learned:
1. Personnel need to take the time to review and plan work. Identify proper procedures, tools, and equipment.
Computing and Networking Infrastructure (CNI)
Don't Get Tricked into Downloading
JLab T-shirt Design Contest submission deadline is Friday!
JLab Calendar of Events
April 4-5: USQCD All Hands Meeting