Jefferson Lab Weekly Briefs
February 22, 2012
The Hall D complex beamline and infrastructure installation is continuing. All 48 Barrel Calorimeter (BCAL) modules, built at the University of Regina, Saskatchewan, Canada, have now arrived at Jefferson Lab. More than 2,200 of the 3,840 Silicon Photomultipliers for the BCAL have been received, and the first full prototype of a readout module is being assembled. The second full six-layer package (of four total needed) has been built for the Forward Drift Chamber. The manufacturing contract has been placed for several hundred Flash ADC-250 modules to be used in pipelined electronics and triggers in all halls.
In Hall A, the refurbished magnet for the target was tested at full field (5 Tesla). This was a major milestone. The work was done by the target group. Hall A staffers are in the midst of the last week of installation and alignment before starting the g2p experiment on Monday (Feb. 27).
After the resolution of issues with the Hall C dump, beam with transverse polarization was delivered to the Q-weak experiment. A series of measurements was taken with vertically and horizontally polarized beam on hydrogen, aluminum and carbon targets at elastic and inelastic QTOR magnet settings. These measurements, as well as providing a correction factor needed in the analysis of production Q-weak data, have a physics interest of their own. After the transverse polarization measurements, data taking continued with longitudinally polarized beam on the hydrogen target.
JSA/JLab Graduate Fellowship Program
JSA/JLab Sabbatical Support Program
The beginning of the week saw no beam to any hall as Hall A continued to reconfigure for a new experiment. Hall B began Monday reconfiguring for the upcoming electron run, and Hall C was down for the investigation of its dump issue. Accelerator time was put to good use with several opportunistic maintenance items completed, along with studies on the new C100 superconducting radiofrequency cavities conducted in the South Linac, installation of various PEPPo equipment in the injector and the resurrection of the 2A synchrotron light monitor in the West Arc. Five-pass beam was set up in preparation of the March run to Hall B. Beam delivery was resumed to Hall C on Thursday. Problems with the Hall B fast shutdown system and vacuum valve controls, and other items including the impending bad weather, prevented delivery to Hall B over the weekend. This allowed Hall C to be the sole receiver of beam over a quiet weekend.
The gun was prepared for operation with a newly installed wafer. First, a high-quantum efficiency surface was prepared, and then the whole gun was conditioned for high-voltage operation. Cryomodule FEL03 was cooled down without incident, and RF conditioning commenced. The FEL vault was re-posted as a radiologically controlled area in preparation for running electron beam.
Center for Theoretical and Computational Physics
The orbital motion of quarks and gluons is expected to play an essential role in accounting for the proton spin and many of its other observable properties. Quantifying orbital angular momentum in the context of the fundamental theory of Quantum Chromodynamics and detecting it in high-energy scattering processes have so far proved extremely challenging. To coordinate the various approaches, researchers held a two-week workshop this month at the Institute of Nuclear Theory at the University of Washington. The results of this meeting will provide guidance for the planning and interpretation of nucleon structure experiments with JLab at 12 GeV, including elastic form factors, deep-inelastic structure functions at large x, and semi-inclusive and exclusive processes.
The machine shop has completed manufacturing all components for the second and third SPX Cryomodule Cavity Assemblies, CRM Crab Cavities (defecting mode crab cavity) for Argonne. The shop also completed all final machining, after electron beam welding, of these components. For Hall A's g2p experiment, the shop completed the manufacture and assembly of the girders up-stream and down-stream of the second FZ magnet. The accompanying mounting components were also completed. The magnet pole extensions for the g2p target magnet were completed. For the FEL, the shop manufactured custom flanges and machined the chamber ends to repair the vacuum leak in the wiggler chamber.
Environment, Safety, Health and Quality
Integrated Safety Management at JLab
At Jefferson Lab, we apply the steps of the Integrated Safety Management System in the planning and execution of work. These include defining the scope of work, analyzing the hazards, developing and implementing hazard controls, performing work within controls, monitoring the work and re-evaluating the task if conditions change, and providing feedback and continuous improvement.
2012 Benefits Open Enrollment Ends Feb. 29
Annual Property and Key Validation Set for March
Tracking Thomas at JLab
Congratulations this week go to Jason Willoughby, Harry Fanning, Percy Harrell, Michelle Shinn and Jim Follkie, who were the first to correctly identify the Feb. 15 location. Honorable mentions go to Sasa Radovic, Ryan Bodenstein, Johnny Leung, John Fischer, Pete Kushnick, Stephen Smith and Doug Higinbotham. 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
Feb. 27: Safety Shoe vendor onsite