12 GeV Upgrade
The fifth sector of the PreShower Calorimeter for CLAS12 is complete and is being tested with cosmic rays. Stacking of lead sheets and scintillator bars threaded with wavelength shifting fibers has started for the sixth and last sector. The sixth and last wire chamber sector for Region 2 has been tested at Old Dominion University, and members of that group are installing high-voltage and readout electronics cards on other completed chambers stored at JLab. The third and fourth Region 1 chambers are being tested at Idaho State University, and the second pair of Region 3 chambers continues being strung at JLab. The mirror substrates for the High Threshold Cerenkov counter are being given their reflective coatings. Assembly of the Forward-Time-Of-Flight (FTOF) 1-b slats has passed the three-quarters point at University of South Carolina. Refurbishment of the existing TOF slat arrays from CLAS continues, with a parallel effort underway for the sectors of the existing Cerenkov Counter. Construction of tooling for winding the Torus prototype coil continues at Fermilab, and the main design for the Torus magnet continues at JLab. The preliminary design review for the Solenoid magnet was held in February, with work continuing on thermal and structural analysis. Production soldering of the superconducting cable to the copper stabilizer for these two magnets has started.
In a new paper (arXiv:1212.3375), the current picture of the nucleus as a system of protons and neutrons interacting amongst themselves via two- and three-body forces and with external electroweak probes via one- and two-body currents is shown to reproduce satisfactorily the empirical static properties of light nuclei with mass number A≤9, including charge radii, magnetic and quadrupole moments, and magnetic dipole transitions between low-lying states of these systems. The calculations are based on quantum Monte Carlo methods, and are therefore exact. It is shown for the first time that contributions associated with two-body components in the electromagnetic current play a crucial role in the A=8 and 9 nuclei in bringing theory into agreement with experiment.
The RF group has continued installation and initial testing activities on the five remaining 12 GeV RF zones needed to complete the upgrade. Work has been slowed while waiting for a vendor to complete some required modifications on waveguide components. In the meantime, work moves ahead on the new Injector RF system (R100), RF separator upgrades and preventive maintenance on all the older 6 GeV RF zones.
The DC power group has focused its attention on cable pulling, termination and connection efforts in the tunnel as new magnets are installed. Modifications to shunt rack wiring required for 12 GeV are also in progress. The procurement activities for new power supplies for quadrupole and dipole magnets are continuing. The first article quadrupole supply is now approved for production. The DC power group is also assisting in troubleshooting a power supply problem in Hall D. The supply is to be used in commissioning the Solenoid Magnet following cool down.
The Instrumentation and Control (I&C) group has been engaged in cable and component assembly, and installation in the tunnel and service buildings for 12 GeV. Work has been done on the BPM (beam position monitor) system, vacuum controls, synchrotron light monitors, and harps and viewers. The I&C group has also supported preparations for re-commissioning the cryomodules, when CHL recovery is complete, by installing necessary radiation monitoring instrumentation.
The Electrical Support group is providing assembly and installation support for the other groups as needed. They are engaged in subsystem and board assembly as well as power and cable installation. The Safety Systems group has been focused on completing both upgrades and new installations in the accelerator and the Halls in support of commissioning and recovery activities.
JLab Calendar of Events
March 25: Safety Shoe Vendor onsite
Environment, Safety, Health and Quality
Continuing with last week's theme about acronyms and their use at Jefferson Lab, this week we will focus on MSDS vs SDS. As many of you know, MSDS is short hand for Material Safety Data Sheet. An MSDS provides essential information regarding a chemical or product, the hazards for health, flammability and reactivity, including the means to protect yourself from exposure. There are other sections of the MSDS that provide additional useful information, and everyone should read and understand the MSDS before using a material for the first time. One can appreciate the complex and burdensome responsibility the creation of an MSDS places on manufacturers and suppliers when trying to deal with similar requirements across the globe for workers with varying levels of education. Over the past decade or more, organizations and governmental agencies around the world have been trying to simplify the sheets and requirements. This effort resulted in a Global Harmonization System (GHS) and resulted in a similar document called the Safety Data Sheet (SDS). Jefferson Lab has updated its electronic MSDS system and you will start seeing slightly different formats and contents as it incorporates SDSs. More information will be coming regarding some of these changes.
JLab Property Custodians: Complete GEN 150 Refresher & Property Validation by March 31
Everyone With a JLab Key Must Do Their Key Validation by March 31
Time To Celebrate Records & Information Month
Tango For Everyone
Tracking Thomas at JLab
|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.|