Jefferson Lab Weekly Briefs
April 18, 2012
12 GeV Upgrade
In response to the reduced FY12 budget and subsequent extended duration of the long shutdown, the 12 GeV team has updated the FY12/13 installation schedules. These have been integrated into the lab-wide shutdown schedule. As installation activities increase in the completed 12 GeV conventional facilities, weekly meetings with Facilities Management & Logistics ensure coordination of resources. The 12 GeV team is working with FML to finalize all transportation, material handling, space, storage and waste/recycle needs.
In Hall A, the g2p experiment has been in a smooth production mode this week. The experiment has completed data collection for several kinematics at the 1.7 GeV energy setting.
In Hall C, the Q-weak experiment has completed most of a measurement of the parity-violating asymmetry of the nucleon to delta transition using a beam energy of 877 MeV. The measurements consist of high-current measurements on hydrogen and aluminum targets, as well as a set of low-current tracking measurements to define the kinematics.
Voting in Users Group Elections Open Through April 30
The accelerator energy was changed and hall passes were reconfigured. Problems with capture resulted in a lost shift. Once that was repaired by the Electrical Engineering Support group, the machine ran well, with virtually uninterrupted beam to all three halls for the rest of the week. Over the weekend, Hall C vacuum degraded, but no specific cause could be found. Various beam currents were sent and pumps and instrumentation were investigated. The cause of the vacuum problem is still under investigation.
This week, FEL Operations staffers supported experiment LOP 12-008, 2.2 Micron Lasing Performance, during the day shift. The team delivered several kilowatt hours of FEL light at wavelengths between 2.14 and 2.25 microns in order to characterize a new set of optics. In the evening, the machine was used for a terahertz experiment, LOP 12-010. Machine utilization has been exceeding 16 hours per day during the week, with machine maintenance occurring on third shift and the weekend. The FEL team plans to continue operating two shifts per day until moving to ultraviolet lasing setup in a week.
Center for Theoretical and Computational Physics
In a recent paper, the scattering phase shifts for the spin-singlet and spin-triplet neutron-Σ¯ systems have been obtained from lattice QCD. The calculations, performed at a pion mass of mπ ~ 389 MeV in two large lattice volumes, and at one lattice spacing, are extrapolated to the physical pion mass using effective field theory. The low-energy neutron-Σ¯ interactions determine, in part, the role of the strange quark in dense matter such as neutron stars, and the results obtained in this calculation strengthen theoretical arguments that the strange quark is a crucial component of dense nuclear matter.
The lab's new CAD and data management software tools, NX and Teamcenter, are in the process of being rolled out across all mechanical design groups. Training for both NX and Teamcenter will be held in April. In the future, it is expected that Teamcenter's role will expand to handle additional documents and engineering data beyond CAD models and drawings.
In addition, electronic signature for CAD drawings, procedures and specifications is in the beta test stage. E-sign will enable drawing/document owners to get signatures without having to print out vellum drawings to carry around for manual signatures. The resulting savings will be in reduced paper usage and a more efficient signature process.
Environment, Safety, Health and Quality
Footwear is also identified under ANSI standards as to whether it is for a male or female. Often women select a shoe from the appropriate men's size. This is a common mistake. Although sometimes the sizing can be adjusted, the best fit and least amount of complications come when a female employee selects footwear designed for the female foot.
JLab's safety shoe vendor is available onsite twice per month, with visits scheduled in advance on JLab's At-A-Glance calendar and also noted in the Briefs' Calendar of Events. All footwear orders should be placed through Webstock and approved prior to the vendor's onsite visit. If you need to procure new or replace aging protective footwear, click the link in the Calender of Events below for more information.
Last Chance to Register for the JAG Run-A-Round
Tracking Thomas at JLab
Congratulations this week go to Harry Fanning, Jason Willoughby and Andrew Burrill, who were the first to correctly identify the April 11 location. Honorable mentions go to Samika Hawkins, Karen Bartek, DeAnn Maddox, Tonya Evans, Brita Hampton, Narciso Gomez, Ron Bartek, Pashupati Dhakal, Mike Martin and Michael Haddox-Schatz. Check out the Tracking Thomas webpage for a better view of his last location and this week's new mystery photo.
JLab Calendar of Events
April 15-19: Beam Instrumentation Workshop