Jefferson Lab Weekly Briefs
September 21, 2011
12 GeV Upgrade
An intermediate design review has been held for the horizontal bend dipole magnet for the Hall C Super High Momentum Spectrometer (SHMS), and the final design review for the Q1 quadrupole magnet is set for early October. Contract awards are being readied for the first two major sections of the main spectrometer carriage, and the rails have arrived. The first large orders of parts have arrived at the power supply vendor for the five large supplies for the SHMS. Scintillator hodoscope assembly is proceeding well and mirror parts for the heavy gas Cerenkov and quartz bars for the quartz hodoscope are in hand.
In Hall A, preparations for the run period continued. Controls for the magnets are being installed and more beamline elements have been installed. The detectors are nearly ready. The target is assembled and is being cooled down for tests. Hall A staffers are behind schedule because of delivery of parts (e.g. the parts for the beam dump). So far, this does not affect the start date for the experiment.
Work continues in the injector for the Polarized Electrons for Polarized Positrons experiment, with the second pedestal and polarimeter table positioned in the tunnel. Dump work at 0L07 continued unabated with shielding stacked in place. Radiofrequency system commissioning work continued on SL24. The North Linac to Machine Control Center trench work continued, with good progress being made. Low-conductivity water was circulated through various box supplies in the W1, W2 and beam switchyard buildings. In addition, box power supply drop tests were completed.
The FEL team made progress, getting beam through the injector setup successfully and working to get beam to the energy-recovery dump. The group successfully set up rf operations, except for one cavity that appears to have excessive losses. A warmup of that module is scheduled for next week in an attempt to fix the problem. Delivery of the ultraviolet wiggler from STI occurred on Friday. It will be placed in the FEL vault this week.
Center for Theoretical and Computational Physics
In a recent paper, the results of a high-statistics, multi-volume lattice QCD exploration of two baryon systems at a pion mass of 390 MeV have been presented. The H-dibaryon and Ξ- Ξ- system are found to be clearly bound at this pion mass. There are indications that both the deuteron and the di-neutron are also bound at this pion mass, with binding energies of Bd = 11(5)(12) MeV and Bnn = 7.1(5.2)(7.3) MeV, respectively.
The Survey and Alignment group has been busy throughout the site over the last month. Some of the major activities include:
For much of the month, the group worked on a surface control survey to support bringing the beam from the CEBAF accelerator to Hall D and a network of control points within the hall. This is in preparation for the installation of the first major equipment in the hall: the solenoid magnet.
Additionally, the group checked the status of some of the magnets after the August earthquake. Four of the 32 stacks of magnets in the arcs and some Hall C components were inspected to check for movement. The results in the accelerator appear to indicate that there was a negligible amount of movement of the checked components. In Hall C, data taken immediately before the event in the hall seem to again indicate very few effects from the earthquake. Since other components had not been measured immediately before the earthquake, the group was not able to make direct comparisons.
Environment, Safety, Health and Quality
Hazards Under Your Desk
American Red Cross Blood Drive
JLab Travel Bookings Managed Through Rearden
Add Your Voice to A National Dialog on Improving Federal Websites
Tracking Thomas at JLab
A belated congratulations for correctly guessing the Sept. 7 location goes to Michael Haddox-Schatz. Congratulations this week go to Jason Willoughby, Harry Fanning and Valerie Bookwalter, who were the first to correctly identify the Sept. 14 location. Honorable mentions go to Ryan Bodenstein, Dick Owen, HyeKyoung Park, Brita Hampton, Stephanie Vermeire, Pashupati Dhakal, Michelle Shinn, Zhe Chen and Amy Lovell. 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
Sept. 26: Safety Shoe Vendor onsite