Jefferson Lab Weekly Briefs
June 16, 2010
Some storage transportainers situated along the South Linac road on the Accelerator Site will be moved on Thursday, June 17, between 8 a.m. and 2 p.m. While the transportainers are being moved, the South Linac road will be intermittently closed. Plan to use CEBAF Blvd. on Thursday, instead of the South Linac road, for all westerly vehicle movement on the Accelerator Site (This is from the back side of the FEL and the CHL, heading toward the experimental halls).
The connector road that connects CEBAF Blvd. to the Halls and Counting House will remain open. For additional information, contact Property Manager Tom Briggs, x5430.
12 GeV Upgrade
The Super High Momentum Spectrometer (SHMS) is being built for Hall C. It has a total of five superconducting magnets. The contract for the horizontal bend magnet was placed with the National Superconducting Cyclotron Laboratory at Michigan State University, where several similar magnets have been built in the past for that facility. The manufacturing design for the first quadrupole magnet (Q1) is progressing at Scientific Magnetics in Abingdon, Oxfordshire, U.K. The bids for the other two quadrupole magnets (Q2 and Q3), and the bids for the dipole magnet are now under evaluation at JLab. The required superconducting cable for the magnet coils is in hand and will be soldered to an extruded copper stabilizer that was recently ordered. The cryogenic control reservoirs for the magnets are under fabrication at Meyer Tool in Chicago. A contract for the production drawings for the SHMS support structure and shield house was recently placed with AMSEC of Newport News. The bids for the five large power supplies have been evaluated, and the contract will be placed following the contract awards for the remaining magnets.
The accelerator was running, with both scheduled and unscheduled downtimes. The machine was optimized to improve Hall A Compton counts. On Thursday, the load shed test was successfully performed. It took more than five hours to resume beam delivery after the test, due to problems with magnets and the viewer system. On Saturday, vacuum valve 1L12A would not open due to the failed micro-switch, which caused more than four hours of down time. The injector Wien angle was changed Saturday and rolled back Monday per a Hall A request.
The FEL team had an excellent week of running, achieving 135 MeV beam energy, lasing in the fundamental at wavelengths as short as 630 nanometers using the infrared wiggler, and the M55 diagnostic was operational for the first time in many months. The team congratulates Raja Singaravelu (ODU), who won a poster prize for his laser niobium nitriding work at the FEL.
In a recent publication from the Excited Baryon Analysis Center (EBAC), the electromagnetic transition form factors of nucleon resonances extracted from extensive meson production data have been reported <arXiv:1006.2196>. This advance has provided new information for understanding the structure of excited nucleons, in particular the long-standing problem of the famous Roper N*(1440) state. The method developed in this effort is an essential theoretical tool for interpreting the data from Hall B in terms of hadron structure calculations within Quantum Chromodynamics.
JLab's Safety Numbers
49 Days since Last Recordable Accident (JLab record: 331)
JLab Calendar of Events
June 24: Lunchtime lecture and slideshow
Environment, Safety, Health & Quality
When the body is unable to cool by sweating, several heat-induced illnesses, such as heat stress, heat exhaustion and heat stroke can occur. Factors leading to these conditions include high temperature and humidity, exposure to direct sun or heat, limited air movement, physical exertion, poor physical condition, some medicines and inadequate tolerance for hot workplaces. Here are several helpful guidelines for preventing heat-related illnesses:
The outside temperature and humidity conditions at JLab are monitored by an onsite meteorological station. SOTRs at Jefferson Lab are notified by pager when the heat index exceeds certain action values. In addition, inside work in non air-conditioned spaces and outside work on hot, humid days are both monitored by the JLab Industrial Hygiene Group (IHG) upon request by supervisors. The IHG can measure heat stress for particular tasks and locations and can provide chilled containers of fluid replenishment beverage when needed. Additional information can be found in ES&H Manual Chapter 6670 Heat and Cold Stress Mitigation Program.
Computing and Networking Infrastructure
Redhat Enterprise Linux Version 3 Support Ending
Personal Dosimeter Change-Out Set for June 30
Volunteer for JLab's Adopt-A-Spot Event
A Grand Lunchtime Lecture and Slideshow
Recharge Today at the Quark Cafe!