Jefferson Lab Weekly Briefs April 9, 2008
Jefferson Lab Weekly Briefs
April 9, 2008
12 GeV Upgrade
A design & safety review of the 12 GeV Cryomodules system was held March 28; the review panel strongly endorsed the team’s work and projected that the design packages will be completed on schedule. The panel also found that the team had responded appropriately to the recent beam-breakup problems seen with Renascence during beam operations.
A vertically integrated test of the low-level RF (LLRF) controls with the self-excited–loop software was performed successfully; the test included the latest versions of the digital board, RF board, and PC/104 IOC-replacement with all operating in concert.
The Arc 10 quadrupole girder drawings were signed off.
The 2008 DOE Office of Science Office of Project Assessment Independent Project Review of the 12 GeV Upgrade Project will be held July 22-24. As in the past, it will be led by Dan Lehman, who heads the Office of Project Assessment in DOE’s Office of Science.
Hall A successfully completed commissioning for experiment E04-007 (Pi-Zero Electroproduction near Threshold) on schedule. On Saturday, April 5, production running was started.
Hall B is currently running the g12 run group that consists of two experiments; One of them searches for hybrid mesons with quantum numbers that cannot be obtained from mesons made from a quark-antiquark pair only. The other is searching for unusual baryons and excited doubly strange cascade baryons.
This reporting period had the three experimental halls splitting 240 hours of continuous wave (CW) beam delivery. As is usual after a long accelerator down period, a few items had to be addressed. The number one issue was various radio frequency cavity problems. As each problem appeared, staff quickly troubleshot the issues and brought RF back online as soon as was possible. The other misbehaving element was a beam loss monitor, which was limiting the current to Hall C located at AT07; it was replaced, and the current limitation disappeared. The accelerator overall is performing very well.
Free-Electron Laser (FEL)
The Optical Transport System (OTS) is now fully functional to every User Lab except Lab 3a. This lab was excluded so as not to disrupt the nanotube generation with the local laser. It has been a very good week for gun test stand (GTS) operation; FEL staff members have learned a lot about what they need to do regarding high-charge generation. Power tests have begun for the three-stage linear ramp for the ultraviolet (UV) QX quadrupoles.
A relativistic model that describes the nucleon as a system of three quarks (Phys. Rev. C77, 015202 (2008)) was applied to the electromagnetic transition of the nucleon to its first excited state, the Δ (1232) (arXiv:0803.3034 [hep-ph]). In this relativistic approach, no relative angular momentum between the spectator quark pair and the quark interacting with the photon is considered. Within this framework, the main contribution to the N -> Δ electromagnetic transition form factor, the magnetic dipole M1, is predicted, although a successful description of this form factor requires significant quark-antiquark effects for Q2 < 3 GeV2.
Safety Shoe Truck
JLab Adopt-A-Spot Event Needs Volunteers
Ultimate Frisbee at JLab
Property Custodians Must Complete Validation of Personal Property by April 15
National Library Week is April 13 - 19
Environment, Safety, Health & Quality
With spring weather around the corner, this is a good time to review bicycle safety both at JLab and at home. Remember, everyone is required to wear an approved, properly fitting helmet while riding a bicycle (or using any type of scooter, in-line skates, or skateboard) at the Lab. Here are a few basic bicycle safety tips:
FEL Fall Protection Net Lesson Learned
The investigation team analyzing this fall protection net discovery noted three primary causes: (1) the line organization assumed that the net was safe and did not verify the completion of the review, (2) the P.E. and his organization failed to properly communicate safety-critical information in a timely manner, and (3) the work supervisor tagged out the net but did not remove his administrative Lockout/Tagout prior to the net's reuse. The FEL shield block relocation worker fall protection is now provided by personal fall arrest systems, which includes full-body harnesses.
Lessons learned are:
Computing and Networking Infrastructure (CNI)
User Audit Starting
Maple 11 Available
Mathematica 6.0.1 Available
JLab's Safety Numbers
203 Days since Last Recordable Accident (JLab record: 319)
JLab Calendar of Events
April 8-11: 2008 International Technical Safety Forum