Jefferson Lab Weekly Briefs March 30, 2011
Jefferson Lab Weekly Briefs
March 30, 2011
12 GeV Upgrade
The first coil for the Q1 quadrupole magnet for the Hall C Super High Momentum Spectrometer has been wound and tested at Scientific Magnetics. The design for the DC power supplies for the SHMS magnets has been reviewed and approved; fabrication will start soon. The copper stabilizer for the superconducting cable is complete, and preparations are underway to start production soldering of the cable to the stabilizer, in preparation for the start of coil winding for the SHMS Q2 and Q3 quadrupole magnets and the dipole magnet. The first of the five cryogenic control reservoirs for the five magnets has been shipped to Michigan State University for the horizontal bend (HB) magnet and the second reservoir is awaiting shipment to Scientific Magnetics. A series of procurements has started for the various sections of the SHMS support structure, with the plan to have all released by the end of FY 2011.
In Hall A, the triple coincidence short-range correlations experiment ran very smoothly last week. The experiment ran on two kinematics, with the second one continuing. In the first setting, the collaboration obtained approximately 100 triple coincidence measurements and 10,000 (e,e'p) for 1.3 Coulombs of data. For the more recent kinematics, the rate is roughly half that and only ~5 triples per shift. The experiment is running according to plan and the data looks good.
Due Friday: APS Award Nominations for Early Career Physicists
Due Friday: 2012 APS Fellowship Submissions
Last week, the CEBAF accelerator delivered beam to Hall A with 92 percent beam availability. On Friday, Hall B started to take beam for calibration of the photon tagger focal plane. Hall C was down due to beamline vacuum problems in its dump area. During beam studies, the X-Y coupling in the injector was minimized, and the 70 Megahertz noise in the injector was eliminated, to improve beam quality for Q-weak; the injector laser spot was moved to boost the current.
The FEL team concluded its vacuum ultraviolet lasing studies in Lab 1. The UV wiggler has now been removed from the FEL building for magnet shipment back to Cornell and jaw shipment to STI Optronics for mounting the Argonne wiggler. The infrared beamline was reconnected to the magnet power supplies in preparation for lasing operations, which commenced this week.
Computational and Theoretical Physics
Mixed systems of N-pions and M-kaons for N + M ≤ 12 are studied in a new paper <arXiv:1103.4362> using lattice QCD to extract the various two- and three-body interactions that occur between pions and kaons. The ground state energies of these systems determine the isospin and strangeness chemical potential. These are found to be in the region where chiral perturbation theory and hadronic models predict a phase transition between a pion condensed phase and a kaon condensed phase.
The Engineering Radiofrequency (EESRF) group has been working on the 12 GeV radiofrequency system in the south linac. The new power supply was received and has been installed in one of the zones. The group has also installed RF control electronics in the same zone to begin testing the control networks. Two engineers recently returned from the Pohang Accelerator Laboratory in South Korea after successfully performing tests using JLab-designed RF control electronics on the lab's accelerating cavities.
JLab Calendar of Events
April 8-9: QCD Evolution Workshop
Environment, Safety, Health and Quality
This year, OSHA celebrates 40 years protecting working men and women. In 1970, about 14,400 workers died on the job in the U.S., with an injury/illness rate of about 10.9 workers out of every 100 workers. By 2009, the numbers dropped to 4,400 deaths and fewer than four injuries/illnesses per 100 workers.
Computing and Networking Infrastructure
Network Outage in CEBAF Center
An App in Every iPot
Due Today: JLab 2011 T-shirt Contest Entries
Don't Talk to Oprah Until You Call Public Affairs
Interested in Golf?
Sling a Softball with JLab Co-workers
Tracking Thomas at JLab
Congratulations to Saptarshi Mandal, who was the first person to identify the correct March 23 location. Honorable mentions go out to Jeff Wilson and Doug Higinbotham. Check out the Tracking Thomas webpage for a better view of his last location and this week's new mystery photo.