Jefferson Lab Weekly Briefs

March 4, 2009

12 GeV Upgrade

A review of the reference design and coil trial winds of the horizontal bend (HB) magnet was completed. This superconducting HB magnet allows for small-angle operation of Hall C's Super High Momentum Spectrometer. This work was performed at the National Superconducting Cyclotron Laboratory at Michigan State University. The review committee validated maturity of the reference design and pointed to items that would assist in the successful construction and operation of this critical magnet.

A series of reviews of the detailed plans for installation of 12-GeV equipment (and de-installation of 6-GeV equipment) in the experimental halls is presently ongoing, with Halls A, C and D reviews completed and Hall B upcoming.

Eugene Chudakov has graciously assumed responsibility as the interim Hall D leader.

Physics

The first European Workshop on CLAS12 was held Feb. 25-28 in Genoa, Italy. With more than 120 registered participants, the attendance was beyond all expectations. In addition to a diverse physics program that covered topics from GPDs (generalized parton distributions) and TMDs (transverse momentum dependent parton distributions) to nuclear correlations, there were talks by representatives of the French and Italian funding agencies and the Nuclear Physics European Collaboration Committee (NuPECC).

At JLab, Hall B continues to run the eg1-dvcs group of experiments that combines measurements of DVCS (deeply virtual Compton scattering) and semi-inclusive pion production on a polarized proton target (NH3). The run has been extended by four days until March 16.

Accelerator

The accelerator was running well for the first couple of days. On Thursday, a failed pump caused the insulating vacuum of cryomodule 1L06 to deteriorate. The vacuum was recovered after the faulty pump was replaced. During the vacuum work, the injector laser spot was moved and the Wien angle was changed. Hall A was changed from pass 4 to 5, and Hall C from pass 5 to 4. On Friday, the vacuum in 1L04 region started to deteriorate. Sunday evening, a power glitch tripped off some magnet box supplies and the Central Helium Liquefier. After the CHL was recovered, cryomodule 1L06 was cryo-cycled to recover the vacuum. Beam delivery resumed at noon on Tuesday.

Free-Electron Laser (FEL)

After several days (a short time considering the work scope) optimizing the FEL with the longer drive laser pulse, the FEL team successfully operated the FEL at 0.93 microns for over five hours. There were no "magic knobs" to turn in order to maintain a high level of performance; the accelerator and laser simply ran well. This is a tribute to everyone’s hard work on improvements.

Theory Center

A relativistic quark model based on the covariant spectator theory has been used to describe the electric quadrupole and the magnetic octupole moments of the Δ resonance (arXiv:0902.4212). The Δ is modeled as a quark-(quark pair) system with a dominant S-wave state (orbital angular momentum zero) plus two small admixtures (about 1%) of D-wave (orbital angular momentum two) components.  If the Δ were a pure S-state, both moments would be exactly zero; but with the predicted D-wave components, they are both negative, suggesting an oblate (pancake-like shape) for both the electric charge and magnetic dipole distributions.

JLab's Safety Numbers

58 Days since Last Recordable Accident (JLab record: 331)
175 Days since Last Lost Workday Accident (JLab record: 676)

JLab Calendar of Events

March 7: Virginia Regional Middle School Science Bowl
March 8: Daylight Saving Time Begins
March 10: Science Series Lecture: The Science of Art Preservation
March 12:13: Spin Structure at Long Distance Workshop
March 25-27: International Workshop on Positrons at Jefferson Lab

 

 

 

Environment, Safety, Health & Quality

Following are two important things to be careful and aware of during winter weather.

In icy conditions, it is best to wear shoes or boots which are specifically designed to grip in ice and snow. An additional measure is to purchase a set of snow and ice traction cleats, a product that can be pulled on over most shoes and is designed to add additional gripping power to icy surfaces.

Another precaution is awareness surrounding ice and packed snow falling from buildings and structures. There have been reports of serious and fatal injuries received from such circumstances. In one case, a woman was struck by ice that slid off the building she was leaving as she shut the door; she suffered near life-threatening injuries. It is advisable to avoid areas where such conditions might occur. In many cases, city and building managers will cordon off higher risk areas. Employees should always be aware of their surroundings, and if you observe an unsafe condition, avoid the condition and contact an ESH&Q Safety Representative, Safety Warden or Facilities Management. If in doubt about who to contact, report the situation to your immediate supervisor or manager.

Computing and Networking Infrastructure (CNI)

E-mail Outage and Reconfiguration Begins Friday, March 20, 10 p.m.
The IT division's CNI group will perform a major reconfiguration of users' e-mail, requiring an outage. The outage will begin Friday, March 20 at 10 p.m. and last through 3 p.m. on Saturday, March 21. No e-mail services will be available during the outage. E-mail sent to JLab addresses from offsite will queue and be delivered after the outage. Reading or sending e-mail from within JLab (including webmail and offsite computers configured to use JLab's e-mail servers) will fail during the outage.

The location of e-mail folders is being changed. Currently, JLab account holders have e-mail folders that are stored in their home directories (/home/user on Unix or J: drive on Windows). The reconfiguration will move these folders out of account holders' home directories and place them on a standalone, isolated file system. Account holders will not have direct access to this new file system. All access to these folders will require an IMAP mail client (i.e. Thunderbird, Pine configured as an IMAP client, etc). Further information about this reconfiguration will be available on the CNI group web page as the date approaches.

jlab.org Alias Change
Some staff and users at JLab use the jlab.org shorthand to login to the central servers from on and offsite. Starting after the March 17 CNI maintenance period, jlab.org will resolve to www.jlab.org from offsite instead of login1.jlab.org as it is now. After that time, users will need to login to login.jlab.org instead. A similar change to the jlab.org alias from onsite is also being tested. Start specifying the machine you want to login to, since the jlab.org alias may not point to what you expect in the future.

CNI Maintenance Period Set for Tuesday, March 17
The CNI group is currently planning a maintenance period for 5-10 p.m. on Tuesday, March 17. During this time, e-mail, home directories, group areas, etc. will be unavailable while the central file server is upgraded. Other items are currently being planned, so continue to check the webpage for additional updates.

Mathematica 7 Now Available
The latest version of Mathematica is now available for use at the lab. On any of the central systems (jlabl1, etc.) you can type 'use mathematica/7' to add the latest version ot your path. Then you can run version 7 by just typing mathematica as usual.

Announcements

2009 Benefits Open Enrollment Ends Today
Jefferson Lab’s 2009 Benefits Open Enrollment will end today, March 4, via the Employee Self Service System. All regular and term employees are eligible for medical, dental, health and dependent care flexible spending accounts, short-term disability and supplemental life insurance. For complete information on benefits options, visit the newly updated Human Resources Benefits webpage.

Daylight-Saving Time Begins March 8
Time to spring ahead this weekend. Before leaving the office on Friday and before going to bed on Saturday, you might want to set your clocks ahead 1 hour. Daylight-Saving Time begins at 2 a.m. on Sunday, March 8. Only set ahead those clocks that don't set themselves from an outside signal.


Come and Join the JAG Dog Training Club!
The JAG Dog Training Club will begin training again in April. Come to the organizational meeting on Wednesday, March 18, at noon in VARC Room 72, the BEAMS Classroom. Whether you want to train in puppy kindergarten, basic manners, therapy dog or dog sports, the JAG Dog Training Club is the organization for you! Whether you're the owner of a new dog or puppy, or if you're a serious canine enthusiast or competitor, the club can help you gain the most from your companion dog. Pizza will be served at the meeting, so R.S.V.P. to Joyce Miller, x7163, or to Brian Kross, x7022.

Have News to Share?
Lab-significant events, announcements and notices can be sent to jlabinfo@jlab.org for consideration for posting in the JLab Weekly Briefs, in the OnTarget newsletter and on the Insight web portal. Additionally, if you have questions about the best method for distributing your message, or if you would like to have your message proofread before it is posted, contact Public Affairs through jlabinfo@jlab.org.

 

 

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