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26 March 2014

The accelerator was able to deliver tune beam to the Hall A dumplet. Work is progressing to provide continuous wave beam to Hall A later this week. The Hall C Super High Momentum Spectrometer effort continues to see multiple work activities in this congested area; workforces include subcontractors and Jefferson Lab employees, so remember to be aware of your surroundings at all times in these areas. Although the concrete subcontractor has finished their work, the structural subcontractor is still working on the work platform, and work will soon begin inside the SHMS to install shielding. Work in the Hall D Tagger area continues; the goal is to complete the subsystems needed to allow tune beam to this area in the 3rd Quarter of FY2014.

12 March 2014

All sectors of the Forward Time of Flight 1-a and FTOF 1-b detector arrays for the CLAS12 spectrometer have been mounted on the forward carriage in Hall B. All "1-a" sectors and three "1-b" sectors have been connected to the new FADCs, discriminators and high voltage and have been read out. Three of the Region 1 Drift Chambers were shipped from Idaho State University to Jefferson Lab, with the remaining two to be shipped in late March. The sixth Region 3 Drift Chamber has had all of its guard and tension wires installed, and about half of its field wires have been strung. This is the last Drift Chamber sector to be built. The next set of production modules of the Silicon Vertex Tracker detector are being assembled and tested at Fermilab, with assembly expected to continue until the fall of 2014. The parts for the SVT assembly structure are now being acquired. The internal frame for the containment vessel for the High Threshold Cerenkov Counter (HTCC) has been assembled, and the carbon-fiber entry dish, Moller cone and related parts have been added. Nineteen coated production mirror segments for the HTCC have arrived and been tested. The mirror refurbishment is complete for the first of three types of mirrors for the existing Low Threshold Cerenkov Counter (LTCC). The box modifications and new supports for the LTCC are also underway.

The practice coil for the CLAS12 Torus magnet was shipped from Fermilab to Jefferson Lab, placed in a test box and cooled to liquid nitrogen temperatures to check stresses and electrical-plus-cooling behavior. The first production coil has been wound at Fermilab and transferred to the coil case. The second coil is being wound, and preparations are underway for the conductor for the third coil. The Torus cryostat factory has been set up and readied to receive the first production coil from Fermilab. The vendor for the CLAS12 Solenoid magnet has submitted the necessary documentation for the final design review scheduled for March 18 at Jefferson Lab.

5 March 2014

The Beam Transport team completed all of the installation and checkout work inside the accelerator enclosure last week. Their work continues downstream of the shield walls. Box power supplies for arcs 7 and 8 are being tested onsite; RSEP9 and arc 9 are on the way to Jefferson Lab from the vendor. The box power supplies for arcs 1-6 have been Personnel Safety System certified. The last delivery of 20 Amp trim power supplies has been received. The PSS stoppers in the beamline to Hall D have been certified.

19 February 2014

The silicon photomultipliers for the Hall D Barrel Calorimeter (BCAL) have been mounted on the light guides. The final parts of the BCAL cooling system are being added in preparation for temperature stabilization tests. The BCAL light monitoring system, built by the University of Athens, is being exercised. Cables are being run to the electronics located in racks below the solenoid magnet. The lead-glass Forward Calorimeter (FCAL), which sits downstream of the BCAL, is having its readout electronics and light monitoring system tested.

The Forward Drift Chamber (FDC) has had its readout cabling added, and it has just had a successful trial insertion into the bore of the BCAL. Work has started to complete FDC electronics installation and then checkout with counter gas and high voltage. The Central Drift Chamber is having preamps added and is being tested section by section prior to being moved to Hall D next month.

One of the two planes of the Time-Of-Flight wall built by Florida State University has been assembled onto the support frame at Jefferson Lab. A source of thin diamond crystals has been found for use just upstream of the tagger magnet as radiators of the bremsstrahlung photons used in Hall D. The resulting scattered electrons from this radiator target will be detected in the tagger hodoscope and tagger microscope, which are being assembled by staff at The Catholic University of America and the University of Connecticut, respectively.

The tagger magnet has been tested and field-mapped at the planned operating field. Installation of front-end electronics, data acquisition electronics, online computers and trigger electronics to render all the above equipment 'live' is proceeding apace, as is installation of needed infrastructure such as cable race, racks, power transformers and distribution, chilled water distribution and the gas distribution system. The bundles of fibers use to transport trigger information and data variously between Hall D floor, counting house and online archiving are on order and being installed.

12 February 2014

On Feb. 5, 2.2 GeV/pass tune beam was transported to 2R and held there for eight hours. This energy is a new record for one pass and is the machine performance needed to eventually deliver 12 GeV beam to Hall D and 11 GeV beam to Halls A, B and C. This demonstrates one of the Key Performance Parameters needed for CD-4A approval of the 12 GeV CEBAF Upgrade project. Starting from pre-calculated settings for the magnets, only minor adjustments were needed for the steering and optics. Beam transport installations for the accelerator are complete. The beamlines to the halls are being completed with vacuum checkout. The rebuilt YB septas in the east spreader/recombiner have been set back in place and are being hooked up and aligned. All radiofrequency and cryomodule scope has been completed. Box supplies for arcs 3-6 are onsite and at various stages of checkout. MARC5 and MARC6 are ready for testing with the dipole magnets. The final shipment of the 20 Amp trim supplies is on the way from the vendor. The Personnel Protection System installations for the 5.5 pass recirculation are complete. The order for the stripline beam position monitors has been awarded. Work is starting on the nano-Amp beam position monitors for Hall D.

5 February 2014

Phase 2 of the Accelerator Readiness Review (ARR) is complete. It was held during the last week of January by reviewers from across the DOE community. The goal of Phase 2 of the ARR was twofold: to determine Jefferson Lab's readiness for the safe and effective delivery of multi-pass continuous wave (CW) beam to Hall A and provide multi-pass tune beam to the Hall D Tagger Vault. Phase 2 followed the same format as Phases 1A and 1B, with both presentations and walk-through inspections of work locations. Despite the schedule changes due to inclement weather that week, the committee's report stated that it as able to "visit all the areas of the accelerator facility and experimental halls critical to this review, and were able to meet and talk with key personnel." The committee noted that there is some work that remains to deliver multi-pass CW beam to Hall A, but it is "well defined and the work is progressing." The committee noted that preparations for beam to the Hall D Tagger Vault were not as advanced as Hall A. Jefferson Lab's internal work control and tracking processes will be used for managing the remaining work. Local ARR Team members will report to the ARR Committee when the requirements have been met for both Hall A and the Hall D Tagger. This is consistent with the previous phases of the ARR.

30 January 2014

The concrete shield house for the Super High Momentum Spectrometer has been constructed on the new support carriage in Hall C. Next will be installation of specialized boron carbide and lead shielding panels. Work continues to upgrade the cryogenics infrastructure for Hall C to accommodate the new spectrometer. Construction of the first two of five spectrometer magnets is well advanced. Welding of the helium vessel is underway at Michigan State University for the HB dipole magnet, while parts for the nitrogen shield, vacuum vessel and support links are ready. The yoke quadrants and four coil assemblies have all been assembled for the Q1 magnet at Scientific Magnetics in the U.K. Welding of this assembly is underway and will be followed by addition of the helium vessel, thermal shield, and outer vacuum cryostat, all of which are ready to be attached. The prototype coil winding was completed for the dipole magnet at Sigmaphi in France and was then epoxied using vacuum pressure impregnation (VPI). Two winding stations are set up at the vendor in anticipation of the start of production coil winding in late February. Very similar tooling and techniques will be used afterward to fabricate the Q2 and Q3 magnets, starting in Spring 2014.

In-tunnel testing of C100-10, the final cryomodule for the 12 GeV Upgrade Project, has been completed. The total voltage for that cryomodule was found to be 110 Megavolts. Installation of all beamline components for the main racetrack has been completed, as well as alignment and vacuum leak checks. The rework of the YB's for the beamline to Hall D has been completed. Vacuum hookups in the transport recombiner and the beam switchyard are complete up to the Personnel Safety System (PSS) stoppers, and the leak check of the Hall A beamline is well underway. A ground current issue for the arc 1 and arc 2 box supplies was discovered and is now resolved. The control problem with the arc 2 box supply has been resolved with the help of an engineer from the vendor, who also installed the corrected components for the IGBT's in the arc 4 box supply. The arc 5 and arc 6 box supplies have been operated at full output current. Deliveries of 20 Amp trim supplies resumed; 65 new units and 20 repaired units were received in December and January; an additional 20 are in transit from the vendor. The order was placed for the electronics for the stripline beam position monitors (BPMs) on the beamline to Hall D. Installation of the PSS stoppers for that beamline is underway, as is PSS installation in the Hall D tagger vault and Hall D proper. Work on the beam dump and water skids for the Hall D tagger has resumed.

15 January 2014

Work is continuing on the support structure for the Hall C Super High Momentum Spectrometer. (Please be aware that the adjacent areas are congested due to the construction activities in progress.) The upgraded CEBAF accelerator has started commissioning activities and this will continue for much of the spring. Phase 2 of the Accelerator Readiness Review (ARR) is scheduled for the end of January. This phase of the ARR will evaluate the preparedness to deliver multi-pass, tuned beam to the Hall D Tagger Vault as well as commissioning and operating Hall A with continuous-wave, multi-pass beam.

8 January 2014

All sectors of the PreShower Calorimeter for CLAS12 have been mounted on the forward carriage in Hall B. One sector has been connected to the new flash analog-to-digital converters (FADCs), discriminators and high voltage and is being read out. The first three sectors of the Forward Time-of-Flight1-a arrays have also been mounted onto the forward carriage. All of the Region 2 Drift Chambers have been shipped from the Old Dominion University group to Jefferson Lab, and the Region 1 Drift Chambers are complete and planned to be shipped from Idaho State University to Jefferson Lab starting this month. The sixth Region 3 Drift Chamber is now mounted on the stringing fixture at Jefferson Lab and is having guard and tension wires installed prior to the start of field- and then sense-wire stringing. This is the last Drift Chamber sector to be built. The first several production modules of the Silicon Vertex Tracker (SVT) barrel have been assembled and fully tested at Fermilab, with assembly expected to continue until the fall of 2014. The parts for the SVT support structure are now being acquired. The internal frame for the containment vessel for the High Threshold Cerenkov Counter (HTCC) has been assembled, and the carbon-fiber entry dish and related parts added. The first seven coated production mirror segments for the HTCC have arrived and have been tested. They will next be assembled into the first of 12 half-sectors for the HTCC mirror. The mirror refurbishment has also been started for the existing Low Threshold Cerenkov Counter. The practice coil for the Torus magnet is complete at Fermilab and has been test fit into its case; the success of this effort led to the decision to start coil production, which is now underway. Major parts for the Torus are starting to arrive and are expected to continue for another six months. The Torus cryostat factory is set up and being readied to receive the practice coil from Fermilab. The vendor for the Solenoid magnet is focusing on completing calculations for a final design review planned for late February/early March and has been asked to start acquiring the manufacturing tooling to wind the Solenoid coils.

 

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