Jefferson Lab Weekly Briefs
September 16, 2015
12 GeV Upgrade
Design of the final section of Hall C downstream beam pipe has started. This portion will reside very close to some of the Super High Momentum Spectrometer magnets when the spectrometer is rotated to forward angles, so the material properties and precise location are important. Similarly, the final detailing for components of the spectrometer vacuum system has been reserved until the mating parts of all five SHMS magnets are absolutely known. This detailing is now moving forward.
Progress on the magnets being fabricated in France are temporarily slowed while the vendor addresses mechanical tolerance issues with some of the cryostat components being built by subcontractors. Nevertheless, there is progress to report: the dipole helium vessel, which encloses the superconducting coils, has passed its pressure and leak tests; the Q2 coil has been placed inside its helium vessel; the Q3 coil and mating collaring rings have been finish-machined and are ready to be permanently joined. Testing of the HB magnet at increasing currents continues as improvements are made to its data-logging systems, the data are analyzed, and the numerical models that describe the magnet are refined.
Center for Theoretical and Computational Physics
Nucleon-nucleon systems are studied with lattice quantum chromodynamics at a pion mass of mπ ~ 450 MeV at three spatial volumes, using three flavors of light quarks. At this mass, the deuteron binding energy is Bd = 14.4+3.2-2.6 MeV, while the di-neutron is bound by Bnn = 12.5+3.0-5.0 MeV. Over the range of energies that are studied, the S-wave scattering phase shifts calculated in the 1S0 and 3S1 - 3D1 channels are found to be similar to those in nature, and indicate repulsive short-range components of the interactions, consistent with phenomenological nucleon-nucleon interactions.
The Mechanical Engineering group has been busy with the following projects:
Help a Kid Become Enthusiastic About Science
Performance Appraisal Training Offered on Friday, Sept. 18
Submit Your Intellectual Property Now Through New Inventor Portal
Jefferson Lab Calendar of Events
Sept. 13-18 XVI International Conference on Hadron Spectroscopy
|JLab Weekly Briefs is an ongoing publication providing information on the status of safety, accelerator operations, experiments, free-electron laser, reviews, upcoming activities and special events. Deadline for submission is every Tuesday by 10 a.m. Submit new items to: Public Affairs or contact Kandice Carter at x7263.|