Jefferson Lab Weekly Briefs
July 28, 2010
12 GeV Upgrade
12 GeV tunnel installation tasks during the upcoming Summer 2010 accelerator shutdown include installation of cables in the new zones of the north and south linacs, magnet cable labels, 10 new floor pedestals for Hall D beam line girders, Arc 10 stands, waveguide hangers, low conductivity water (LCW) west arc headers, and extension of the north linac master oscillator. Lessons learned during this shutdown will be used to refine plans for installation work during the six-month shutdown starting in May 2011.
As part of an effort to coordinate the 12 GeV Project needs, the JLab facilities group is developing an on-line database for related space and storage requests including offsite rentals. Coordination of equipment for material handling and transportation continues in order to ensure installation activities are adequately supported to perform the work safely.
Over the last week, beam was delivered to Hall B for about four shifts. Hall A was down for installation. Hall B had issues with its target. Hall C continued to work on its target. The accelerator was available and was used for beam studies. The CHL tripped twice.
The first six UV optics have been installed and aligned, representing significant progress toward first lasing in this wavelength range.
After extensive installation activities - which finished ahead of schedule - the temporary wiggler chamber was reinstalled and pumped down, and electron beam recovered with good transmission through the cookie-cutter defining the wiggler chamber aperture. A short bunch (~300 fsec FHWM) was generated with this configuration.
Theory Center staff, in collaboration with researchers from Brazil and Australia, have studied a possible mass shift of the J/Ψ meson in cold nuclear matter <arXiv:1007.2220 [nucl-th]>. The J/Ψ mass shift arising from the modification of the D and D* meson loops at normal nuclear matter density is found to range from -16 MeV to -24 MeV under a wide variation of values of the cutoff masses. This can give insight into the partial restoration of chiral symmetry and QCD color van der Walls forces in the nuclear medium, and can be explored experimentally at JLab with the 12 GeV
American Red Cross Blood Drive
JLab Community Invited to Summer Interns Poster Session
High school and college interns that participated in JLab's summer science enrichment programs will share their experiences and projects during a poster session scheduled for Friday, July 30, from 11:45 a.m. to 1:30 p.m. in the CEBAF Center lobby. The entire JLab community is invited to stop in any time during the poster session. The six participants of the High School Summer Honors Program, and the 30 participants of either the Science Undergraduate Laboratory Internship or the Old Dominion University Research Experiences for Undergraduates programs, will present posters they developed based on their work or research projects.
August Beam Physics Symposium Honors Yaroslav Derbenev
JLab's Safety Numbers
12 Days since Last Recordable Accident (JLab record: 331)
JLab Calendar of Events
July 28: American Red Cross Blood Drive
Aug. 23-25: PAC 36