Jefferson Lab Weekly Briefs February 27, 2008

Jefferson Lab Weekly Briefs

February 27, 2008


In Hall A, installation work for the next experiment, E04-007 (Pi-Zero Electroproduction near Threshold), is progressing on schedule. Both the BigBite magnet and the associated detector system are in the hall and are being assembled.

Hall B completed the g9-FROST run, a search for new excited nucleon states. The run was carried out with a longitudinally polarized target and linearly as well as circularly polarized photons. At the end of the run, the transverse holding coil was installed in the Frozen Spin Target (FROST), and, for the first time, the longitudinal polarization was transferred adiabatically to a transverse polarization by ramping up the transverse holding saddle coil and simultaneously de-energizing the solenoid coil. The degree of polarization was fully preserved during this process. This configuration of FROST will be used in the next g9 run.



The Scheduled Accelerator Down (SAD) continued in full force during the past week. Some notable points of the work performed include the following areas:

  • Injector: laser alignment and Pgun 3 photocathode made;
  • Cryo: NL06 cryomodule connections underway, cooled to 2K; SL07 cryomodule warmed up, prepped for removal; Joule-Thompson (JT) valve on SL10 replaced; SL09 cryomodule installed;
  • Personnel Safety System: semi-annual system certifications were completed;
  • Alignment: surveys of tunnels, starting with injector to end of NL;
  • Vacuum: successful test of new superconducting radiofrequency (SRF) vacuum reset board; the Central Helium Liquefier tripped during this time frame but was quickly brought back online.


Free-Electron Laser (FEL)

The FEL gun is in processing and evolving surface gas. It is expected to reach its operating voltage late this week. The drive laser is being set up for operation of the Gun Test Stand (GTS). The FEL has an approved Laser Safety Operations Procedure for the GTS. FEL staff members have also been working on the ultraviolet beamline layout and are about 75 percent done with magnet and diagnostic locations, so assembly and installation can proceed when the money arrives from the Air Force Research Laboratory.

Theory Center

Photoproduction of pion and omega meson reactions studied in all JLab experimental halls is a powerful probe of the resonance structure of the nucleon. A simultaneous description of these reactions has been made in a dynamical coupled channel calculation, arXiv:0802.3383 [nucl-th], at the Excited Baryon Analysis Center (EBAC). The calculation provides insight into the nucleon resonances, production of omega mesons with polarized photons, and the cross section for the important and elusive reaction of omega mesons with nucleons.


JLab's Safety Numbers

161 Days since Last Recordable Accident (JLab record: 319)
480 Days since Last Lost Workday Accident (JLab record: 480)

JLab Calendar of Events

March 1: Virginia Regional Middle School Science Bowl
March 4: ODU Physics Colloquium: Lawrence Krauss
March 5: JLab Physics Colloquium: Albrecht Karle, University of Wisconsin
March 6-8: Photon-Hadron Physics with the GlueX Detector
March 25: Science Series Lecture: The Civil War Unplugged


Environment, Safety, Health & Quality

Pennsylvania motorists recently encountered an unusual traffic hazard: a three-ton wood-chipper on wheels that had broken loose from a truck and collided with a minivan, resulting in three deaths. The truck driver had not checked to make sure the chipper was securely hitched. He also failed to connect the safety chains, which are supposed to keep a trailer attached if the hookup fails.

Runaway trailers are a little-known but persistent cause of devastating crashes, deaths and injuries across the country. A large majority of runaway trailers were light- and medium-duty trailers, as opposed to big rigs. Many of the crashes stemmed from elementary mistakes, such as failing to engage a locking device when hitching a trailer, and rarely was just one mistake responsible. More often, drivers neglected a series of precautions, any one of which might have prevented a tragedy.

A survey of more than 300 trailer owners in 2006 indicated that most were "lacking in knowledge of basic safety and proper towing procedures, and few have had any real training or instruction." If you, a friend or a family member own or use a light- or medium-duty trailer, you can help keep roads safe by making sure that all of the manufacturer's instructions are followed for each use.

Consumer Product Safety Commission Recalls
Three recent Consumer Product Safety Commission (CPSC) voluntary recalls involved consumer products with fairly wide usage. The CPSC alert for Campbell Hausfeld air compressors noted protective covers were not made of fire-retardant material. A recall of Aloha Housewares portable electric heaters mentioned that the heaters had been sold at Wal-Mart and other retail locations. The third CPSC alert involved fiberglass extension ladders made by Louisville Ladder under several brand names.

Computing and Networking Infrastructure

CNI Systems Maintenance next week
Maintenance Day is scheduled for March 4, 5-10 p.m.  For more information, visit the Computer Center webpages.

Automatic Installation of Microsoft Office
On the evening of March 4, the Computer Center will automatically install Office 2007 on all JLab Common User Environment (Computer Center-managed) Windows systems that haven’t already installed it. *Non-Windows systems, including Unix-based systems such as Mac OS X and Linux, will not be affected.* To sign up for training in the new features of Office 2007, see the announcement. As always, should you encounter difficulties with your computer, call or visit the Computer Center Help Desk, x7155 or CEBAF Center F200.


JLab Colloquium and Public Lecture
Albrecht Karle, University of Wisconsin, will present “Astronomy with Neutrinos” in the CEBAF Center auditorium at 4 p.m. on Wednesday, March 5. IceCube is a giant neutrino telescope in the most remote region of our planet: Antartica. A smaller instrument is being constructed in the Mediterranean Sea. Karle will describe where these efforts stand and what scientists are measuring now.

Property Validation Season Nears
Nearly every employee at JLab is a property custodian, responsible for proper use, control, physical protection and disposition of assigned property. The annual property custodian validation process will run from March 1-15. During this period, each custodian must "validate" all of the items on his or her inventory list and take the Property Custodian Refresher GEN 150 training (about five minutes).

JAG Dog Sports Training Club Informational Meeting Tommorrow
If you are interested in training your dog in basic obedience, agility skills or freestyle dog dancing, you're invited to Come, Sit, Stay at an informational meeting! Those interested in forming a JAG Dog Sports Training Club will hold an hour-long brownbag lunch in VARC room 72 at noon, Thursday, Feb. 28. For more information, contact Joyce Miller at x7163 or or Brian Kross at x7022 or


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