Jefferson Lab Weekly Briefs
June 29, 2011
12 GeV Upgrade
The North and South Access building low-conductivity water systems upgrade is 85 percent complete and slightly ahead of schedule. There are a total of four systems being upgraded. Two North Access building systems provide cooling downstairs for the west arc magnets and upstairs for the radiofrequency zones in the North Linac Service building and the power supplies in the North Access building. Two South Access building systems provide cooling for the east arc and the South Linac Service building. The piping is complete. When the electrical and controls are also complete, the systems will be filled with de-ionized water and hydrostatic pressure tests will be performed to check for leaks.
Hall A staffers made incremental progress on installation for the November run period. Several pieces of equipment were installed and aligned. Some procurements are a bit behind schedule. There were three new experiment proposals being discussed and reviewed by the Hall A coordinating committee for this Friday's Program Advisory Committee submission deadline.
The sixth scheduled week of the accelerator down went well. Installation work continues for the injector experiment (PEPPo), including the installation of cable trays. New rf-zone work is going very well, and the first klystron is in place. Modifications to cryogenic gas pipes were performed in support of the 12 GeV Upgrade project. Many other tasks were continued or started.
Work on the gun was completed and the gun is under vacuum. Preparations are underway for the bake, but the gun vacuum is already looking very good. Several beamline components in the rest of the injector were replaced, with several other replacements planned for this week. The quarter cryomodule upstream beamline valve has already been replaced with the downstream valve replacement, a task that had been planned for this week.
Center for Theoretical and Computational Physics
A recent publication has demonstrated differences between the EBAC unitary coupled-channels model and the commonly used isobar model, raising concerns about the reliability of the excited meson states extracted from isobar model analysis. The paper concludes that a coupled-channel approach with a three-particle unitarity condition must be used to analyze three-meson decay data for exploring hybrid or exotic mesons. The spectrum of excited mesons will be the focus of the future GlueX project in Hall D and a key component of CLAS12 in Hall B at 12 GeV.
The survey and alignment group reports that the initial alignment (step 2A) of the refurbished dipoles in the west arc is continuing and is complete up to stack 7 (approximately the midpoint of the west arc). This initial alignment allows the vacuum and electrical group to complete its required hookup tasks. The stands for the slow raster and the FZ1 magnet for the g2p experiment in Hall A were also aligned. A check to see if the tunnel is moving as a result of the construction in the northeast corner of the accelerator shows changes below 2 millimeters between the initial survey in April 2011 and late June 2011. This is being monitored to ensure no gross movement occurs due to the construction breakthrough for the beamline to Hall D.
The magnet measurement factory (MMF) reports that magnet removal has been completed for the west arc. The refurbishment team is working through west arc stack 13. Measurement and installation has been completed for west arc stacks 1-8. Stack 9 measurement and installation is currently under way.
Based on the performance of the magnet factory, alignment and installation crews, approval was given this week to begin magnet upgrade work on arcs 7 and 9 passes in the east arc. Moving forward, magnet factory crews will concentrate efforts on east arc stacks 9-16 to complete the south side of the machine as soon as possible.
Environment, Safety, Health and Quality
In the U.S., someone dies from a traumatic injury every three minutes, according to the National Trauma Institute. The organization warns that the number of traumas is likely to spike during the coming summer months. NTI offers the following tips to keep families safe this summer:
Email Vacation Utility and Phone Vacation Greetings Reminder
Quarterly Publications Training Offered July 12
Lunchtime Seminar on July 19 for Managing Stress in the Workplace
JSA Initiatives Fund Call for Proposals Announced
Minority Undergraduate Research Assistantship
Tracking Thomas at JLab
Congratulations to Dick Owen, who was the first person to correctly identify the June 22 location. An honorable mention goes out to Jane Worley. 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
JLab Summer 2011 Education Calendar
May 23 - July 29: Science Undergraduate Laboratory Internship