Jefferson Lab Weekly Briefs February 11, 2009
Jefferson Lab Weekly Briefs
February 11, 2009
12 GeV Upgrade
The vendors for the FY09 civil construction contracts have been selected. The Central Helium Liquefier Building Addition contract for approximately $1.5 million was awarded to Ritchie-Curbow Construction Company of Newport News The pre-construction conference was held Jan. 13, and completion is scheduled for December 2009. The contractor is working on administrative submittals for approval prior to site mobilization. Notice of award for the Hall D Complex contract, approximately $14 million, was sent on Jan. 21 to S.B. Ballard Construction Company of Virginia Beach. Upon approval of the performance and payment bonds, a pre-construction conference will be held. The Hall D Complex is a phased contract with completion scheduled in fall 2011.
In Hall A, the transition to Experiment E06-014, Precision Measurements of the Neutron d2: Towards the Electric and Magnetic Color Polarizabilities, went smoothly, and the experiment is currently taking commissioning data.
Hall B completed the e1-dvcs run successfully and is now in production mode with the eg1-dvcs run group. The transition required the removal of the superconducting solenoid magnet and installation and re-commissioning of the Hall B polarized target and the slow raster system. This was all successfully accomplished by the Target Group and the Hall B technical and scientific staff. The polarized target is now operating at high polarization.
Production data taking for the Spin Asymmetries of the Nucleon Experiment is ongoing, although overall efficiencies are lower than hoped due to a variety of target and detector issues. The polarized target magnet has operated well since the repairs in December, but it has quenched several times. In each case, the quench protection circuitry has functioned correctly. SANE has obtained about 45% of the proposed statistics for perpendicular target polarization at 4.8 GeV. The experiment is currently taking perpendicular data at 5.9 GeV with improved efficiency.
The accelerator continued to perform well with a continued low trip rate. The injector laser spot was moved to boost current for the halls. Six hours were spent on Tuesday for beam studies. Hall A was changed from pass 5 to pass 1, and Hall C was changed from pass 4 to pass 5. Magnets ARC3A, MAG9R01 and MAM3S03 were not stable and the problems were fixed, causing a couple of hours of downtime.
Free-Electron Laser (FEL)
FEL staff members are proceeding with continuous wave running and performing a number of measurements for Joint Technology Office efforts. Last week, a significant amount of time was spent in support of the Innovative Naval Prototype programs for industrial contractors.
In a recent paper (arXiv:0812.1605 [hep-ph]), the orbital angular momentum is calculated both of the 'quark' in the scalar diquark model and that of the electron in QED (to order α, the electromagnetic coupling). The orbital angular momentum is compared in two decompositions (Jaffe-Manohar vs. Ji) proposed in the literature, and the importance of the vector potential in the definition of orbital angular momentum is estimated. The vector potential adds a negative correction to the orbital angular momentum for an electron with positive spin.
The Instrument, Controls and Diagnostic (ICS) group has been busy on a number of projects. West Arc Service Building W3 CAMAC to VME control changeover final engineering change orders were completed, and procurements are ongoing. Final installation in building W3 will take place during the summer down. Additionally, ICS is proceeding with Hall C HKS/HES (High Resolution Kaon Spectrometer/High Resolution Electron Spectrometer) beamline diagnostic system work. The pre-rack assembly and wiring is nearly complete, with documentation, and awaiting Hall C for installation. The BPM (beam position monitor) RF (radio frequency) module prototype evaluation is reaching completion. ICS is also working on replacing obsolete network switches in the halls. This should also be finished during the summer down. ICS also continues to work on the beam loss accounting system with the downconverter preliminary design being completed and the printed circuit board design commencing.
Environment, Safety, Health & Quality
During the past week, the site experienced three notable events. One involved first aid; fortunately, the worker was able to return to work immediately.
The first incident involved a fall from an eight-foot step ladder; it occurred in CEBAF Center Room L210 (Computer Center), during overhead maintenance. A step ladder had been placed on an inclined surface, with the worker standing on the third step from bottom. While the worker was performing overhead work, he shifted his weight, causing the ladder to slide. He reached for nearby ceiling grid components to steady himself; subsequently, he fell to ther floor, along with a fluorescent light fixture. Several corrective actions have been proposed to address this issue; they are currently being reviewed by a member of the Worker's Safety Committee. A lesson learned has been entered into the JLab Corporate Operating Experience (COE) database.
The other two notable events are still under investigation. They involve actual or potential equipment damage and schedule loss. The first event centered on Hall C chicane work, where a protective shield was not placed on the target during pivot access work. The second event involved a U-tube separating from a crymodule during testing. Work was stopped until an agreement on interim corrective actions could be reached.
The common items between these three events include initial reporting and Extent of Condition analyses. Initial reporting enables us to better understand trends and how they affect our workforce, as discussed in the Sept. 26 Montage. Extent of Condition enables us to identify and implement sitewide corrective actions. The underlying motive for each is to ensure that schedule and monetary losses occur only once and that measures are put into place that will prevent similar events in all lab areas.
U.S. Postal Service Mail Delivery at JLab
Shipping & Receiving has been accepting and sorting incorrectly addressed mail, totaling approximately four to five crates a day. Most of this is catalogs, sale flyers, newsletters and similar third-class bulk mailings (e.g. junk mail). Shipping & Receiving cannot continue to handle this volume of incorrectly addressed mail. Starting on March 2, incorrectly addressed mail will be returned to the sender.
JLab T-Shirt Design Contest Underway!
Quark Cafe Celebrates Valentine's Day
Radiation Worker Training Notice
12 GeV Adopt-A-Spot Litter Pickup on Feb. 20 Needs Volunteers
JLab Meeting Rooms Locked After Core Business Hours for Property Protection
JLab's Safety Numbers
37 Days since Last Recordable Accident (JLab record: 331)
JLab Calendar of Events
Feb. 15: JSA/JLab Graduate Fellowship Application Deadline