Jefferson Lab Weekly Briefs
September 24, 2008
12 GeV Upgrade
The CLAS12 drift chambers in Hall B are designed to provide high tracking accuracy, while maintaining high-rate capability and large acceptance. This necessitates small drift cells and very thin endplates with low-profile onboard electronics and cables. A full-scale prototype of a region-1 chamber was built, strung and instrumented as a joint JLab & Old Dominion University project. As a result, the construction technique was validated, and the board and cable mounting schemes were refined. Electrostatic deflections of wire positions were insignificant.
The Forward Drift Chambers (FDCs) in Hall D provide the necessary tracking of charged particles traveling in the forward direction through the GlueX apparatus. The test wire winding on four FDC composite wire frames has been completed at the Indiana University Cyclotron Facility. The test results indicate that the composite wire frame design meets all structural requirements and validates that the required precise tolerances for relative position distribution and wire tension can be met. Valuable lessons were learned to improve on FDC construction.
In Hall A, installation of the polarized helium-3 target is proceeding smoothly. The assembly of the polarized target proper has been started with the oven now in position. The installation of the new electron detector for the Compton polarimeter, designed by the University of Clermont-Ferrand, has been completed, and the beamline is back under vacuum. The BigBite detector system has been installed in place and surveyed. The cooldown of both High Resolution Spectrometers (HRS) is underway, with the left one on cold return and the right one to follow as soon as the cooldown of the left has been completed.
In Hall B, the cooldown of the Torus magnet began on Sept. 18 and is expected to continue for 10-12 days. After that, the Saclay Solenoid magnet will be cooled down. The Cerenkov counter has been closed up again and leak tested, waiting for a final testing of the new lifting fixture for installation in CLAS. The inner calorimeter needed for the E1-DVCS run has been moved to the Hall for final preparations.
In preparation for the Spin Asymmetries of the Nucleon Experiment (SANE) in Hall C, the polarized target girder and the polarized target service platform have been installed. A detector shielding wall has been installed near the target. The polarized target has been moved into the hall and is being readied for installation.
The unit substation LN1 rebuilt transformer was delivered and then installed with the help of a crane. After the electrical connections were made, LN1 was powered successfully. The warmup of Cryomodule SL05 was begun. Turbines on the Central Helium Liquefier Main Cold Box were re-started after the replacement of compressor C-6’s main shaft seal. Personnel Safety System certification of RF (radiofrequncy) and box supplies continued.
Free-Electron Laser (FEL)
The FEL is being prepared for startup of operations. The advanced drive laser is ready, the SRF (superconducting radiofrequency) cooldown started, and the gun high-voltage processing is underway.
A recent Theory Center paper (arXiv:0809.2582 [hep-ph]), featuring a collaborative effort with an Old Dominion University undergraduate supported by the JSA RIFA (Research Internship for Foreign Undergraduates) program, considers how the results of lattice QCD calculations of charmonium can be reconciled with successful non-relativistic potential models. It provides a bound-state model description of lattice data that indicates, for example, "hybrid" states, which require excited gluonic fields in their structure - a suggestion that is becoming increasingly relevant experimentally with observations of states like the Y(4260). The light-quark analogs of these states form the principal focus of the GlueX experiment.
The Safety Systems group completed the functional certification of the CEBAF accelerator, an important step required for upcoming operations. Functional certification involves verifying that the PSS can shut off hazardous equipment if needed.
The alignment and metrology group completed the transfer of the CEBAF accelerator coordinate control to the new surface monuments. The coordinate system in the main accelerator is required for the construction of Hall D. Preliminary reduction of the data, at 1 sigma, show errors of less than 0.5 millimeters over the length of the accelerator linacs, or an error of 1.2 parts per million.
JLab's Safety Numbers
14 Days since Last Recordable Accident (JLab record: 331)
JLab Calendar of Events
Sept. 25: JSA's Electronic Commerce Vendor Show
Environment, Safety, Health & Quality
The Quality Assurance and Continuous Improvement organization is in the process of transmitting a series of procedures to a variety of site personnel for required reading and/or general QA/CI program awareness. The organization is working with Division Safety Officers to determine a list of who should read and understand such procedures. In addition, QA/CI organization personnel are beginning a series of quality and safety minute presentations for MCC, FEL, SRF, and other weekly meetings to educate and/or demonstrate the procedures, processes, systems and tools expected to be a part of the site-wide QA/CI programs. If you have any questions about the JSA QA/CI program, feel free to contact Bruce Lenzer, QA/CI Manager, x7586.
Records Management for Individuals
Beware of Poisonous Spiders Onsite
Computing and Networking Infrastructure (CNI)
CEBAF Center Wings A&B Network Outage
JLab Computer Purchasing Policy
A purchasing policy will be released October 1 that further explains how this program will be implemented in the future. Additional information on EPEAT can be found at: http://www.epeat.net/.
For now, those wanting to procure a new desktop system can submit a CCPR stating who the system is for, how it will be used and what Project and Org to use for the purchase. The CNI group will submit a requisition for the appropriate system on their behalf.
P2P Software Not Allowed on JLab Network
Effective immediately, systems participating in prohibited P2P traffic will be automatically blocked from the JLab network for one hour. At the end of the hour, the ban will automatically be lifted and normal network access will resume if the P2P activity has stopped. This is a change from the current procedure, which requires the user to contact the HelpDesk and have the ban lifted manually. This change should help users who get blocked during weekends, holidays and other times when the HelpDesk is closed.
JSA Electronic Commerce Vendor Show
Blood Drive Set for October 7
$4-off Coupons for State Fair Ride Wristband
Tee'em Up for the JLab 2008 Fall Golf Tournament!