Jefferson Lab Weekly Briefs
March 28, 2012
12 GeV UpgradePre-planning of work activities greatly improves the overall safety of the task. Recently, the two Central Helium Liquefier (CHL-2) cold boxes that were delivered and placed into final positions required complex lifts. The operation took two large cranes, several riggers and other support personnel working in unison to complete the task. Through extensive pre-planning and clear communication of the roles and responsibilities for the people involved, these complex lifts were completed without incident.
PhysicsHall A has been down this week while staffers recovered from the septum magnet incident. The incident happened on Saturday, March 17. A connection from the right-septum magnet to the power supply became loose, developing a resistive contact, and overheated. A thermal runaway destroyed this connection. A second damage occurred on the magnet windings, about 1 meter away from the connector. There, due to the sudden drop in current, a spike in voltage caused a short between the magnet windings and the iron yolk. The power supply tripped off. Three coil windings (out of 28) are shorted. To repair the magnet, Hall A workers have jumpered over these three windings and replaced the connector. A ground fault circuit interrupter is being installed on the power supply, and heat-sensitive switches are being installed in various locations, including the connectors. The connectors have been torqued to specification and will be regularly re-torqued to ensure a tight connection. A panel of two electrical engineers from Engineering and a Hall C physicist has reviewed the incident. Once this panel is satisfied with the repairs, Hall A will be certified to continue running. With three windings jumpered out, the magnet will have 11 percent less field for a given current, but the field quality and magnetic optics should still be sufficient.
In Hall C, the Q-weak experiment continued with production data taking on hydrogen intermixed with occasional background runs with an aluminum target. Some studies of the effects of beam halo were done by blocking one of the eight Q-weak detector octants with a tungsten shutter.
Minority Undergraduate Research Assistantship
JLab is seeking candidates for a research assistantship to provide an opportunity for a minority undergraduate student to work on projects that are part of the lab’s research program or directly related to the scientific or engineering aspects of the research program. This assistantship is funded by the JSA Initiatives Fund Program and will provide funds to support the student at the university during the 2012 - 2013 academic year. Nominations are due April 6 and must be submitted by the faculty sponsor before the student may apply. Faculty sponsors may obtain more information and submit their nomination online.
AcceleratorMultiple unsuccessful attempts to reconfigure Hall B for five-pass beam during the past week were traced to a shorted quadrupole magnet at the 9A20 girder in Arc 9. Beam has not been at 5 pass since before the start of the summer down. C100 RF zones continue to be challenging to operate, as Operations staff attempt to raise them to their nominal 98 MeV gradients. On Saturday, March 24, a beam strike resulted in a vacuum event, which interrupted beam to both operating halls for several shifts. By Sunday, beam was restored to Hall C at its requested pass and to Hall B at 4 pass due to an inability to transport beam beyond Arc 9. On Monday morning, the accelerator was opened up to reactivate the cathode. The 9A20 quadrupole problem was found and various other maintenance activities were performed.
Free-Electron LaserThe FEL ran well this week, and the team started the infrared experimental program by measuring mirror performance at 1.6 microns.
Center for Theoretical and Computational PhysicsIn a new paper, QCD calculations of the heavy-hadron axial couplings g1, g2, and g3 are reported. These quantities are the low-energy constants of heavy-hadron chiral perturbation theory and determine the strong decay widths of charm and bottom baryons. The analysis makes use of lattice QCD at light quark masses and chiral perturbation theory to control all systematic uncertainties.
EngineeringThe alignment group has been busy in Hall A supporting the g2p experiment. The field crews have aligned the chicane magnets and diagnostics through four energy changes. Additionally, alignment has carried out an initial inspection/fiducialization of the Hall D CDC detector at Carnegie Mellon University. For Hall D, the group surveyed the solenoid and control monuments in the hall. For Hall B, the region 3 drift chambers were surveyed. Additionally, the group is transitioning and readying data and software files to prepare for the upcoming 12 GeV Upgrade down. The magnet measurement group has finished measuring 11 of the 20 new spreader and recombiner magnets. In addition, magnet measurement is preparing for the upcoming down when they will have to refurbish many of the existing machine magnets.
Environment, Safety, Health and QualityEliminating Your Car's Blind Spots
Many drivers were taught to set the driver’s side outside mirror so that the driver can barely see along the left side of their car. But this configuration creates blind spots for the driver that can hide vehicles. Now the National Highway Transportation Safety Administration offers new guidelines for eliminating blind spots. Using the Blindzone Glare Elimination Mirror Method, mirrors are set to give the driver a view of the lanes farther out, instead of alongside, the vehicle. The method eliminates large blind spots in which vehicles can hide. For more information and an illustration of this method, visit the NHTSA website.
AnnouncementsTime Collection Server Upgrade Set for Thursday
On Thursday, the Time Collection server will be down 7 a.m.-1 p.m. Employees will not be able to log into the system during this time, so plan to edit your timesheet before or after this maintenance window. If you have any questions or comments, contact David Sheppard, x5814. Once upgraded, the Time Collection/Employee Self Service system will feature a new look. The sign-on procedure is the same as before, and there have been no significant changes to the timesheet and ESS functions. Maintaining employee work schedules has changed, so an email explaining the differences between the old system and the new system will be sent out to those affected by this change. If you have any questions about the upgraded system, use the Contact Us link in the TC/ESS system, and someone will assist in resolving your issue.
Tornado Drill Survey
Tina Menefee, JLab's emergency manager, is conducting a short Tornado Drill Response and Lessons Learned Survey. If you participated in the drill on March 20 and have not already done so, take a few minutes to complete the survey. The survey is posted to a JLab-approved link to a business that provides survey tools.
Interactive Shipping Authorization Form Now Available
Need to ship an item from JLab? Shipping and Receiving now offers an interactive shipping authorization form. Once filled out online, the form is automatically forwarded for electronic signatures. The form also features the Proforma Invoice needed for international shipments. The information needed for the proforma is automatically loaded from information you complete on the shipping form. After completion, submitting the form will send both the shipper form and Proforma Invoice for review and signatures.
Volunteers Needed for May 19 JLab Open House
JLab's Open House is just around the corner, and this year's event, themed "Passport to Science," will be bigger than ever. Volunteers of all types provide the public with a safe, fun and educational experience. Sign up now through April 16. Hourly employees will be paid, with advance approval from his/her supervisor. Each volunteer will receive a T-shirt to wear for the Open House. When signing up, be prepared to provide your T-shirt size and your cell phone number. There will be mandatory volunteer briefings. Volunteers leading tours or staffing displays or activities for specific programs or locations should consult with that area's volunteer coordinator. Area volunteer coordinators are listed on the web sign-up page. Direct general-event volunteer questions to Tina Menefee, x5490, cell 768-4030.
Seminar on Women in Physics Offered April 5
Elizabeth Simmons, theoretical physicist and Dean of Lyman Briggs College at Michigan State University, will offer insights into Women in Physics in the U.S.: Numbers, Challenge and Solutions, in a seminar sponsored by Human Resources. The seminar is open to all and will take place in the CEBAF Center auditorium on Thursday, April 5 at 3 p.m. Simmons has garnered many awards and distinctions, and is the February 2012 APS CSWP Woman Physicist of the Month, a AAAS Fellow, and an APS Fellow.
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 Pashupati Dhakal and Samika Hawkins, who were the first to correctly identify the March 21 location. Honorable mentions go to Jim Follkie, Subashini De Silva and Robert Martin. Check out the Tracking Thomas webpage for a better view of his last location and this week's new mystery photo.
JLab Calendar of EventsMarch 29: Newport News Public Schools Business & Education STEM Summit
April 3: JLab Publications Refresher Seminar
April 5: Seminar: Women in Physics
April 11: JLab Colloquium and Public Lecture - Ani Aprahamian
April 11: Teachers Science Night at JLab
April 25: JAG Run-A-Round
April 30: FLUKA Training Course