Jefferson Lab Weekly Briefs May 14, 2014
Jefferson Lab Weekly Briefs
May 14, 2014
12 GeV Upgrade
The Hall D Barrel Calorimeter, Forward Calorimeter, Forward Drift Chamber, Central Drift Chamber and Time of Flight wall, i.e. the five large subsystems of the main spectrometer in Hall D, have all been installed in their final positions and are being commissioned. The tagger and pair spectrometer magnets have been mapped, and installation work is starting on the fixed array tagger hodoscope and pair spectrometer detectors that accompany them. The detector elements for the tagger microscope and the start counter are being assembled, with arrival at Jefferson Lab expected in the summer. The counting house has been fitted out with racks of readout and trigger electronics, together with the cabling and fiber networks that interconnect them. Operation of the electronics, the trigger network and the data transfer from the experiment’s digitizers all the way to the data storage silos has been demonstrated, with regular tests and tune-up ongoing. An order has been placed for the thin diamond crystals needed to create the Hall D photon beam. These will be graded at a synchrotron light source and selected for subsequent thinning to 20 microns, as needed for the coherent bremsstrahlung radiator.
JSA Sabbatical and Research Leave Support at Jefferson Lab
Jefferson Lab Published Journal Articles, May 5-9
Remember to submit your papers for approval to the Jefferson Lab Publications database.
Center for Theoretical and Computational Physics
A detailed Amplitude Analysis of two photon production of ππ and KK, using S-matrix constraints and fitting all available data, including the latest high statistics results from Belle, yields a single partial wave solution up to 1.4 GeV. The two photon couplings of the σ/f0(500), f0(980) and f2(1270) are determined from the residues of the resonance poles. Thanks to the very recent construction of a dispersive framework for Light-by-Light reactions, the partial wave amplitudes presented in this paper will bring a new precision to the on-going calculation of the hadronic contribution to the anomalous magnetic moment of the muon. Reducing these uncertainties is essential if new experiments planned at Fermilab and J-PARC are to deduce hints of physics beyond the Standard Model that can compete with a series of Jefferson Lab experiments, such as Q-weak and APEX.
The Cryogenics Department was reorganized internally, splitting into two major sub-groups. The Cryogenic Operations Group, headed by Mat Wright, will operate and maintain the cryogenic plants at Central Helium Liquefier 1, CHL2, the Standby Refrigerator, the End Station Refrigerator (ESR), the Hall D Refrigerator, and the Cryogenics Test Facility (CTF). The Cryogenic Engineering and Design Group, headed by Kelly Dixon, is organized to support cryogenic engineering project work for Jefferson Lab and outside projects, such as FRIB and LCLS2. Jonathan Creel is the new Cryogenics Department Head.
The beginning of the Scheduled Accelerator Down (SAD) marks the end of the preliminary running of the CHL1 on the North Linac and CHL2 on the South Linac in the 12 GeV configuration. Both plants operated well. The CHL1 will be shut down and warmed up for summer maintenance, including the cleaning of the 4 Kelvin cold box top-end heat exchangers and the replacement of the compressor system carbon inside the large adsorber. The CHL2 will be reconfigured and will support both Linacs at 4 K for the duration of the SAD. The ESR is operating normally and is supporting the cooldown of Hall C. The CTF plant just cooled down the F100 cryomodule in the test cave for testing. The Hall D cold box was disassembled, damaged internal 80 K/20 K beds were removed, valves were repaired and re-configured, and all internal piping cleaned. The cold box is being reassembled with new diodes. A re-commissioning test is planned for late June.
Environment, Safety, Health and Quality
PPE: The Last Mitigation of an Electrical Hazard
Computing and Networking Infrastructure
Internet Failover on Sunday, May 18, 6-8 a.m.
IT Division Maintenance on Tuesday, May 20, 5-7 p.m.
Short Phone Outages on Saturday, May 31
Public Zimbra Briefcase Lives Up to Its Name
Jefferson Lab Spam and Virus Filter Software Changing
Upcoming Jefferson Lab Pager Audit
Last-Chance Open House Volunteer Session Scheduled
Electronic Tour Database
See Jefferson Lab Researchers Speak at Particle Fever Debut
Jefferson Lab Calendar of Events
May 17: JLab Open House: Accelerating Discovery
|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.|