Jefferson Lab Weekly Briefs April 20, 2011
Jefferson Lab Weekly Briefs
April 20, 2011
12 GeV Upgrade
Assembly of the first 12 GeV cryomodule continues, and assembly of the second cavity string into the second cryomodule has begun. All beam transport quadrupole magnet girders for arc 10 have been assembled. The new contract for the septum magnets has been awarded. Three klystrons and two cathode power supplies for the radiofrequency systems have been received; the cathode power supplies have been installed in the south linac. The vendor for the new 4 Kelvin coldbox for the expansion of the Central Helium Liquefier is making good progress; the vendor for the warm compressors for that expansion is having some schedule problems due to delays in their subcontractors’ component deliveries. Field measurements of the 4-meter dipole magnets for arc 10 are complete.
Last week in Hall A, the short-range correlations experiment successfully conluded Wednesday. Hall staffers then opened Hall A for a tour for the DIS conference attendees. After the tour, staffers ran experiment E08-009 for He4(e,e'p). This was a one-day experiment, and it concluded successfully Friday morning. On Friday, Hall A started the x > 2 experiment E08-014. For Friday and Saturday, the accelerator was able to deliver 95 microamp beam to Hall A while also delivering 165 microamps to Hall C. This combined current of 260 microamps is a significant achievement for the accelerator. Unfortunately, a Saturday thunderstorm knocked out the accelerator and many systems. The hall recovered by noon Sunday and continued to run E08-014. The experiment has run well except for that.
Last week, Hall C took Q-weak production data on the hydrogen target and made background measurements with aluminum. On Saturday, the downstream vacuum deteriorated. Fortunately, this was due to a failed vacuum pump, which was replaced. Also, the Q-weak target warmed up due to the thunderstorms, and a water leak developed in the Q-weak power supply. After addressing these problems and re-liquefying the target, Q-weak returned to data taking, starting with a short measurement of the asymmetry of the electro-induced proton to Delta transition.
Research Assistantship Nominations Due May 6
JSA Promising Young Scientist Program
During the week, a CEBAF record high of 262 microamps of combined beam current was delivered to Halls A and C, resulting in another CEBAF record for the integrated charge of 16.2 Coulombs extracted from the Cathode in a 24-hour period. Hall B has been offline for installation of HDice. On Wednesday, beam studies were conducted, the beat frequency modulator was installed in the injector and some RF cavities were recovered. On Thursday, the injector Wien was flipped from left to right for the Q-weak experiment. The simultaneous high-current operations were interrupted Saturday morning due to a vacuum problem in Hall C that prevented beam delivery for the rest of the week. Hall A continued to take beam until a storm in the area caused power line fluctuations Saturday evening, resulting in all the magnet box power supplies, the Central Helium Liquefier and the End Station Refrigerator to trip.
FEL staffers successfully ran beam irradiation tests last week, despite the failure of the building hot water heater. The group also installed 2-micron mirrors in preparation for power tests over the next two weeks.
Facilities Management and Logistics
After-Hours Site Access
The cryogenics group is continuing its efforts to support cryogenic operations of the main accelerator, experimental halls and the Test Lab. Cryogenic fabrication shop staffers are continuing their efforts in manufacturing the Central Helium Liquefier II compressor room, as well as the 10,000 liter helium dewar at the Cryogenic Test Facility.
Environment, Safety, Health and Quality
With the advent of warmer weather, many "fair weather" riders have returned to the roads. While motorcycles save gasoline and reduce pollution, it also means many more less-experienced riders or those with rusty skills have returned to the roads. The following tips from the Virginia State Police will help riders and drivers share the road more safely.
Particle Accelerator Posters On Display
April is Records and Information Management Month
Get in on Home Energy Savings With 'Next Step' Program
Annual Property Validation Ends Next Week
Annual Key Validation Ends Next Week
Education Seeks Projects, Mentors for Summer High School Interns
Agilent Tour Bus Onsite
Tracking Thomas at JLab
Congratulations to Michael Wilson, who was the first person to correctly identify the April 13 location. Honorable mentions go out to Paul Letta, Karl Slifer, Mitch Dunn, Jacki Smith, Brian Kross, Dick Owen, Brian Carpenter, Mike Martin, Casey Heck, Todd Coates, Kelly Tremblay, Jim Boyce, Curt Hovater, Danny Machie, Randy Michaud, John Conger, Tina Johnson, Lori Zuckerman and George Biallas. 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
April 20: JLab's Annual Region II Teacher Night