Jefferson Lab Weekly Briefs
October 12, 2011
In Hall A, the polarized proton target is being examined for repair work, with multiple shorts to ground. Hall A staffers are waiting for shipments of superconducting wire to come in before attempting to make and then test the repairs. The rest of the installation is making normal progress. If the repair work goes well, experiments should begin Dec. 1.
Many injector Personnel Safety System pre-checks have been completed in preparation for final injector PSS certification, and PSS Run/Safe box 22 was relocated to northeast stub. Gun lasers have been made coincident and centered and have now been turned over to the Q-weak experimenters. The capture water skid is up and running. The iron-core solenoid magent has been installed on the Polarized Electrons for Polarized Positrons experiment detector stand. On Friday, the injector was locked up for a successful gun high-potential test.
The North Access building fibercast flange leak has been repaired. North and South Access Building low conductivity water system is now in fully automatic mode, and LCW flow to 0L07 beam dump has been initiated. The beam loss accounting system checked out okay, and the injector beam position monitor checks found a bad radiofrequency module, which was swapped out for a good one. Waveguide joints in 2L25 were leak checked, with two gaskets replaced and connections torqued. The trim rack hot checkout continued; bad cards are being pulled for rework.
The semi-load-lock system for the DC gun was successfully tested for mechanical function. The Laser Micro-Engineering Station was used to cut several gallium arsenide photocathode wafers for the first time.The DC gun was then set up for a high-temperature bake underway by week's end. Progress was made in understanding the source of noise in the photocathode drive laser. Finally, the DC high-voltage power supply was tested without load up to 570 kilovolts, with no trips over six hours.
An Electron-Ion Collider (EIC) with a center-of-mass energy ~20-70 GeV is presently discussed as a next-generation facility for nuclear physics in the U.S. after the JLab 12 GeV Upgrade. A group of physicists has compiled a short, introductory level overview of the EIC nuclear physics program, placing it in the context of the 12 GeV Upgrade and emphasizing the qualitatively new information that could be obtained with the collider. The key objectives of this new facility are to explore the three-dimensional structure of the nucleon in Quantum Chromodynamics (including sea quarks and gluons, spatial distributions, orbital motion, polarization and correlations), the fundamental color fields in nuclei (including nuclear quark and gluon densities, coherence effects and transparency), and the basic process of conversion of color charge to hadrons (including hadronization, quark and gluon propagation through matter and in-medium jets).
The Mechanical Engineering group reports success in its 12 GeV beam transport activities for the Six Month Down. The west arc is complete and the east arc is almost complete, with some final alignment work to be completed on the northeast side. Arc 10 installation is complete, except for components that would interfere with 6 GeV operations. All linac warm girders have been installed, and all songsheets have been updated and posted on the web.
In Hall A, the major components for the g2p/GEp beamline have been installed, hooked up and tested; staffers are now awaiting final parts to install the last two girders on either side of the FZ2 magnet.
A pressure profile analysis of the Hall C dump helium tube system was completed; the analysis is required for defining the system's control strategy.
The new revision of the Conduct of Engineering Manual has been released. Information sessions for Engineering Division groups will be held over the coming months.
The Electrical Engineering Systems group reports that DC power group personnel participated in a vendor design review for new 20 amp trim power supplies for the 12 GeV Upgrade. The testing of the First Article 12 GeV box power supply was witnessed in Bologna, Italy, by DC power group engineers.
Environment, Safety, Health and Quality
How Clean Is Inside Your Windshield?
Computing and Networking Infrastructure
Computer System Maintenance Scheduled for Tuesday
Major Systems Outage on Friday, Dec. 23
Informal Reception to Honor JLab's Founding Director, Hermann Grunder
United Way Campaign Pledge Forms Available Online
United Way Campaign Raffle
Tracking Thomas at JLab
Congratulations this week go to Dick Owen, Connie Adams and Lamont Williams, who were the only people to correctly identify the Oct. 5 location! 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
Oct. 18-20: DOE Project Review of the 12 GeV Upgrade