Jefferson Lab Weekly Briefs August 25, 2010
Jefferson Lab Weekly Briefs
August 25, 2010
12 GeV Upgrade
The summer 2010 accelerator shutdown started Aug. 13 and is well underway. The shutdown includes many 12 GeV Upgrade tunnel installation tasks. Tasks completed to date include: installation of two-inch low conductivity water piping in the west arc, replacement of the master oscillator, emptying of cable penetrations for the new zones, installation of three zones of electrical conduit for cables, placement of forms for the remaining two cryomodule base plates in the south linac, and layout of Hall D/Arc 10 stands. Remaining installation tasks include installation of the five-, four- and three-inch low conductivity water piping in the west arc and installation of electrical conduit and cables in seven of the new zones.
In Hall C, a trial cooldown of the Q-weak high-power target loop was conducted; the loop volume was filled with liquid hydrogen, with the target cell bypassed. This cooldown has provided useful operational information for future cooldowns of the target when the replacement target cell, currently under fabrication, is installed.
The first week of the scheduled accelerator down went well. Many scheduled activities got started, including installation of refurbished radiofrequency module C50-4 at 2L15, a new master oscillator (which will allow path-length adjustment), new pager equipment and new viewers at 1C05 and 3C05. In addition, magnet-related work was done and some systems (including 4-channel beam position monitors, arc vacuum and viewers harps) in W1 service building were converted from CAMAC to VWE/PC104.
The FEL had a major achievement this week with first lasing of the ultraviolet FEL. Initial operation was robust at 700 nanometers (visible red light), producing over 150 Watts of power in an 11 micron detuning curve. This week, the team intends to switch to the UV mirrors and establish lasing in that wavelength range. The FEL team wishes to thank all who supported this effort during the four years of construction and commissioning.
A long-term visitor to the Theory Center, in collaboration with physicists in Germany and Austria, has investigated the properties of the Δ and Ω baryons within a QCD motivated framework provided by the Poincare covariant Dyson-Schwinger/Bethe-Salpeter equations <arXiv:1008.3184 [hep-ph]>. The three-quark core contributions to the hadrons' masses and electromagnetic form factors are evaluated using a consistent setup for the fundamental interactions within the baryon: the quark-gluon, quark-quark and quark-photon interactions. The predictions for the baryon decuplet's electromagnetic multipoles are in good agreement with lattice calculations, quark model analyses, and the available experimental data.
Computing and Networking Infrastructure
Last weekend, a JLab computer user account was compromised by hackers and used to send phishing e-mails to other JLab accounts. The "from" address of the phishing e-mail appeared to be Helpdesk@jlab.org, and the address used to send the e-mail belonged to a valid JLab user. However, the link in the e-mail went to an offsite address. Additional accounts were compromised when JLab computer users clicked the link and provided the requested information. This necessitated a JLab password change request.
Information Technology personnel would like to remind everyone that under no circumstances will JLab staff ask for your user name and password in an e-mail, nor will staffers request that you click a link going offsite to enter your user information.
If you get a suspicious e-mail and are unsure of its legitimacy, contact the IT Helpdesk at x7155 or at email@example.com.
Onsite TIAA-CREF Counseling Offered
Accelerator End-of-Run Party
United Way School Tools Drive Ends Tuesday
JLab's Safety Numbers
40 Days since Last Recordable Accident (JLab record: 331)
JLab Calendar of Events