Jefferson Lab Weekly Briefs April 2, 2008
Jefferson Lab Weekly Briefs
April 2, 2008
12 GeV Upgrade
Over the last few months, four independent reviews have been held of various physics detector systems, and five more reviews are planned in April and May. These reviews give valuable feedback to the scientists and engineers as they complete system design packages in preparation for the July 2008 DOE SC Office of Project Assessment Independent Project Review. Last week, the Hall D tracking and related particle identification systems were reviewed. During the closeout, reviewers provided high marks on progress in the last year and the quality of the presentations. A review of the CLAS12 Silicon Vertex Tracker detector will be held this week. Both Halls B and C are in the final preparations for a design review of their seven superconducting spectrometer magnets. In Hall C, particle background simulations are ongoing to finalize the shield house design.
Hall A has successfully completed installation activities for experiments E04-007 (Pi-Zero Electroproduction near Threshold) and E08-007 (GEp/GMp at low Q2-values) on schedule. On Monday, March 31, the cryotarget system was cooled down as the final step before taking beam into the hall.
This week saw the Scheduled Accelerator Down (SAD) come to a successful conclusion and the ramp up of Accelerator Operations to get ready for beam delivery to the experimental halls. Various factors made the optics setup very difficult. However, an excellent setup was achieved after some very hard work by many staff members. Production beam delivery was started to all three experimental halls. Efforts of Note:
Free-Electron Laser (FEL)
FEL staff continued preparations toward producing high-charge bunches in the gun test stand by optimizing drive laser performance and revisiting the PARMELA modeling to account for the final configuration. The team is working to produce and measure the bunches as this is being written. Staff also finished mapping the last sextupole and received a new ultra-sensitive terahertz (THz) detector for that lab.
Recently, Myhrer and Thomas showed (arXiv:0709.4067 [hep-ph]) that the fraction of the spin of the proton carried by its quarks, now experimentally around 33 percent, can be understood in terms of the basic features of its nonperturbative structure, namely relativity, chiral symmetry and the one-gluon-exchange hyperfine interaction. A new Theory Center paper (arXiv:0803.2775 [hep-ph]) has now shown that the missing spin is actually carried as orbital angular momentum, primarily by up and anti-up quarks. While this picture changes dramatically under QCD evolution, the predictions are in rather good agreement with recent lattice calculations, as well as with the recent results from deeply virtual Compton scattering from JLab and Hermes.
Property Custodians Must Complete Validation of Personal Property by April 15
As noted in the March On Target newsletter, changes in the property program have reduced the number of items that the Lab must track and inventory. For example, the dollar threshold for “sensitive” items that have no electronic memory has been raised from $150 to $300. The validation link can be found on the JLab Insight page. On the Insight Front Page tab, look down the Personal Information column on the left, and click on the “Property validation” link.
National Library Week is April 13 - 19
JLab Calendar of Events
April 4-5: USQCD All Hands Meeting
Environment, Safety, Health & Quality
With the weather starting to turn warmer, many of us are starting another year of yard work. The American Society of Hand Therapists suggests some basic gardening safety practices. It is important to remember that yard/gardening activities involve many repetitive tasks such as raking, weeding, digging and pruning. You can help avoid injuries by following these safety tips:
"Suspect" Rigging Items Discovery
Computing and Networking Infrastructure (CNI)
User Audit Starting
Maple 11 Available
Mathematica 6.0.1 Available
If you receive such a fraudulent email, the safest thing to do is simply delete it. If you have any questions, call the bank's customer service line using the phone number printed on your latest statement and ask them to verify its authenticity. If you think that you may have already fallen victim to a banking scam, contact your institution immediately.
As always, you may feel free to forward a copy of any suspicious email you receive to email@example.com.
JLab's Safety Numbers
196 Days since Last Recordable Accident (JLab record: 319)