Jefferson Lab Weekly Briefs
May 12, 2010
EEL Parking Lot Closed Thursday-Sunday
Paving Operations are set to begin in the EEL parking lot. The lot will be closed for parking of all vehicles Thursday-Sunday. On Friday, the lot will be closed to all traffic, including shipping and receiving deliveries, golf carts and shop vehicles. If all work is completed on time, the lot will re-open Monday morning. Once open, the lot will be accessible via BCS Road. Enter the lot carefully and be alert to the new traffic pattern, since parking space placement will have changed. For more information, see the detailed announcement and parking map online.
12 GeV Upgrade
The sixth (of 37) 4-meter dipole magnet has been received. Deliveries of the new beam transport quadrupole magnets have reached 66; all magnets that have been tested have been significantly better than the specifications. Preliminary testing of the first article klystron by the vendor has begun. Deliveries continue for the cryomodule cold tuners and waveguides; the contract for the warm tuner assemblies has been awarded. The vendor for the iron assemblies to be added to the existing beam transport dipoles has ordered the necessary materials. Critical sub-contracts for the 4.5K coldbox (turbines and absorbers) were placed by the coldbox vendor. A preliminary manufacturer’s engineering review was held at the vendor site for the Central Helium Liquefier warm compressors, and the design was approved. The vendor subsequently placed orders for electric motors, compressors, heat exchangers and coolers.
Overall, the accelerator has been running well, with low trip rates. On Thursday, the CHL tripped, causing more than six hours of downtime. The cause of the trip is still under investigation. On Friday, the injector laser spot was moved to boost the quantum efficiency. Over the weekend, Hall B beam showed some instability. On Monday, the orbits from the injector to Hall B were optimized, which stabilized Hall B beam current and positions.
The FEL team ran beam experiments for two user groups last week in terahertz and infrared, testing the performance and stability of the FEL and optical transport. The team also ran some injector halo tests.
Researchers from JLab and Trinity College, Dublin, have computed the excited spectrum of mesons using lattice QCD. The latest results <arXiv:1004.4930> include the identification of states with exotic quantum numbers, a vector-hybrid candidate and many high-spin states (up to spin-four). The next steps are to develop methods for dealing with two-particle states before eventually calculating meson-photon couplings. This program of calculations will inform expected production rates at GlueX, as well as providing the ab initio predictions for the meson masses demanded by experiment.
JLab's Safety Numbers
14 Days since Last Recordable Accident (JLab record: 331)
JLab Calendar of Events
May 12: JLab's 25th Annual Run-A-Round
Environment, Safety, Health & Quality
Hand Safety - Your hands are your most important tool!
Protect your hands from injury by following these guidelines:
Computing and Networking Infrastructure
Get Your Race Bib or Register for the Run-A-Round
Only Two TIAA-CREF Counseling Sessions Left!
Clean the Bay Day Seeks Volunteers