12 GeV Upgrade

The performance of the C100 cryomodule has now been successfully demonstrated at 104 Megavolts for more than one hour. Preparations are complete for a test at 108 MV with full beam loading this week. Assembly of the sixth C100 has been completed. Installation of the compressors and 4.5 Kelvin coldbox for the Central Helium Liquefier-2 continues. The beam position monitors for arc 10 are ready for installation. The first-article electronics for the stripline beam position monitors passed acceptance testing.

Physics

Hall A ran beautifully all week, collecting a lot of data. One more week to go before the shutdown.

In addition to data taking on liquid hydrogen (LH2) and aluminum targets, the Q-weak experiment in Hall C has made several background measurements and carried out several test plans that will aid in analysis of the data. Although Hall C experienced significant flooding from Tuesday's storm, there was no apparent equipment damage, and Hall C is expected to receive beam for the last two days of 6 GeV operations.

Accelerator

The week began with a high rate of beam interruptions due to accelerating cavities tripping off on various faults. Several cavities in the North Linac were restored to service in an effort to lower the trip rate. Wednesday was a beam studies day, with tests for the Polarized Electrons for Polarized Positrons experiment and the C100 cryomodules being performed. Some more cavities in the North Linac were also recovered and brought online again, helping to lower the beam trip rate. Thursday saw a small vacuum problem corrected by an adjustment of the setpoint at which the vacuum valve closes. On Friday, a controller that handles magnets was misidentified and was inadvertently rebooted, which resulted in the loss of a few hours to restore the magnets and correct the resulting orbit and beam optics. The final weekend this year of running the main accelerator went extremely well, with no major interruptions to the beam.

Free-Electron Laser

First lasing on the visible ultraviolet system was achieved with the new wiggler. Substantial gain was observed. The system is being optimized and minor hardware failures are being fixed in preparation for user experiments later this month. The FEL team also began hardware installation preparations for the DarkLight effort planned for July.

Engineering

The Machine Shop is presently manufacturing or continuing to manufacture:

• CLAS 12 High-Threshold Cerenkov Counter (HTCC) mold mirror facet block 2 assembly for Hall B and the mirror assembly fixture;
• 170 dipole-lengthening shims for the 12 GeV Upgrade;
• Two complete solenoid coil assemblies for the Polarized Electrons for Polarized Positrons experiment's upcoming run in the injector;
• 30 stripline beam position monitors; and
• ZA-style vacuum chamber assembly for the 12 GeV East Arc and south east recombiner. The first article has been completed and passed vacuum testing. Seven more chambers will follow.

The shop also received the new vertical milling machining center that is needed for reworking magnet cores associated with the 12 GeV Upgrade. The shop is in the process of setting the machine up. The shop has processed 156 job requests since April 2.

Environment, Safety, Health and Quality

Verify or Die: Never Assume Circuits Are Off!
These are the basic Lock Out/Tag Out procedure steps, according to both the Occupational Safety and Health Administration and the National Fire Protection Association:

• Prepare for shutdown;
• Shut down the equipment;
• Isolate and block hazardous energy sources;
• Apply locks and tags;
• Release stored energy; and
• Verify.

If all of the steps are performed correctly, verification becomes a non-event. If, however, one error is made in any of the prescribed steps, verification of zero energy can save your life. Visit the link for a complete toolbox talk on this topic.

Computing and Networking Infrastructure

Email Migrations into New System Continue
The CNI group is continuing to migrate staff and some users into the new email and calendar suite, Zimbra. These migrations are going well, with nearly 440 staff and users migrated into Zimbra and about 125 still left to migrate. These migrations are occurring overnight, and you will receive an email around noon on the day you are scheduled to be migrated. For more information, see the article in the March 16 OnTarget newsletter.

CNI Maintenance Period Set for May 22
The CNI group is planning a maintenance period for next Tuesday, 5-10 p.m. During this time, patches to Firefox, Thunderbird and Java, as well as Linux and Windows desktops, will be released. Plan on rebooting your desktop when convenient on Wednesday, May 23, in order to complete the installation of these patches. In addition, work is being planned for the home, mail and group file servers. This work is not expected to cause any outages to these services.

Announcements

JLab 2012 T-Shirts Available for Purchase
The T-shirts unveiled at this year's Run-A-Round are now available for purchase for $7 each at the CEBAF Center front desk.

DOE Lab Breakthroughs in 140 Characters or Less
JLab will join SLAC National Accelerator Lab and Fermilab in a live Tweetup online this Thursday, May 17, at 1 p.m. The tweetup, called #LabChat: Particle Accelerators, Lasers and Discovery Science, will feature experts from all three labs. JLabbers Gigi Ciovati and Pashupati Dhakal will share their expertise in superconducting radiofrequency technology by answering questions submitted by interested tweeters with the #LabChat hashtag.

Tracking Thomas at JLab
Little Thomas is visiting all corners of the JLab campus. If you can identify his location this week, email Kandice Carter with your guess. Guesses are accepted through Friday.

Congratulations this week go to Russell Mammei, who was the first to correctly identify the May 9 location. An honorable mention goes to Harry Fanning. 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

May 14-17: QCD Evolution Workshop
May 19: JLab's 2012 Open House: Passport to Science
May 21: Safety Shoe vendor onsite
May 28: Memorial Day holiday, JLab closed
June 4-6: JLab Users Group Workshop and Annual Meeting
June 6: End of 6 GeV Era Party
June 18-22: Program Advisory Committee Meeting (PAC39)