Jefferson Lab Weekly Briefs
August 19, 2015
12 GeV Upgrade
Shielding blocks are being placed in Hall C to create a wall between the new Super High Momentum Spectrometer (SHMS) and the beam dump. The SHMS is shorter, and can rotate to larger angles, than would be possible if the shielding were part of the spectrometer itself. Jefferson Lab and university staff completed work on one of the trigger hodoscopes recently, and now half of the SHMS detectors are completely installed inside the concrete shield house, as scheduled. The other detectors are undergoing final assembly and cosmic-ray tests. The Physics Division review panel has approved a continuation of the testing program of the Horizontal Bend (HB) magnet, allowing the magnet to be energized to just over half of its ultimate operating current. Construction of the final three superconducting magnets for the SHMS are progressing, with the dipole magnet coil now sealed within its welded helium vessel, the Q2 coil squeezed inside its collaring rings, and the final potting finished for the Q3 magnet coil.
Center for Theoretical and Computational Physics
State-of-the-art lattice QCD calculations are beginning to include isospin breaking corrections from QED and the up-down quark mass splitting. The inclusion of QED effects faces a number of challenges that stem from the disparate length scales associated with QED and QCD: typically, the spatial volume is used to regulate the long-distance physics, which leads to substantial corrections in simulations at finite lattice volumes. A new paper investigates a novel infrared regularization scheme involving a photon mass, and finds good control of the systematics associated with the infinite volume extrapolation. This method will enable the study of elastic charged hadron interactions with lattice QCD.
Over the past couple of weeks, the Alignment group has been involved in the re-installation of several components in the accelerator, including the 750 MHz radiofrequency separators, viewers and harps in the extractor region. They also assisted in the bubble chamber work in the injector and have updated survey control in the beam switchyard.
Jefferson Lab Calendar of Events
Aug. 19-21: Q-weak Collaboration Meeting
Computing and Networking Infrastructure
Critical Internet Explorer Patch Released
MIS Outage Set for Saturday, Aug. 29
Volunteers Sought for Sept. 11 United Way Day of Caring
2015 Jefferson Lab Fall Golf Outing Set for Sept. 18
Feds Feed Families Local Campaign
|JLab Weekly Briefs is an ongoing publication providing information on the status of safety, accelerator operations, experiments, free-electron laser, reviews, upcoming activities and special events. Deadline for submission is every Tuesday by 10 a.m. Submit new items to: Public Affairs or contact Kandice Carter at x7263.|