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12 GeV Updates

22 October 2014

Civil construction for the 12 GeV Upgrade project has resumed with the backup cooling towers for the low conductivity water (LCW) systems at the North and South Access Buildings. This work was combined with the Utilities Infrastructure Modernization's cooling tower work at various locations around the accelerator site. The prime contractor is Warwick Plumbing & Heating of Newport News. WPH has done various projects at the Lab before including Hall D and Technology and Engineering Development Facility project mechanical work and the Central Helium Liquefier-1 replacement cooling towers. The 12 GeV backup towers were delivered last week and set in place on the existing structure steel platforms. The solicitation for the last of the 12 GeV Project Civil scope, Tunnel Air Conditioning, has been posted with proposals due on Oct 30. The vendor site visit for this solicitation was held Oct 16.

24 September 2014

The voltage-tracking regulators for the extraction YA's are operational, and control screens have been implemented. This completes the scope for the 12 GeV Project power systems. The scope for the 12 GeV Project safety systems has also been completed. The magnets for the fast-feedback system for the Hall D beamline have been installed, and the first of the nano-Amp beam position monitors for the Hall D beamline has been installed.

20 August 2014

The last drift chamber for Hall B's CLAS12, one for Region 3, has had all wires strung, window added, feed-thru pins potted, and is being readied for testing. Three of the remaining 17 drift chamber sectors are having instrumentation completed, with the balance ready for installation. The production modules of the Silicon Vertex Tracker (SVT) barrel continue being assembled and tested at Fermilab, with over 30 now completed. The innermost modules of the SVT have been mounted onto the support frame/cooling plate in the clean room at Jefferson Lab and have been tested in place. The containment vessel for the High Threshold Cerenkov Counter (HTCC) has had the photomultiplier tube supports added and is being readied for mirror installation. All of the coated production mirror segments for the HTCC are being glued to form 12 half-sector mirrors. These will then be glued along their edges to form the full HTCC mirror. The aluminized Lexan strips that will be placed on the hyperbolic mirror segments of the Low Threshold Cerenkov Counter (LTCC) have arrived from the vendor and are being attached. A second full-size practice coil for the Torus magnet was wound, epoxy-potted and then sectioned to test the revised potting procedure. A good coating of all the coil elements was found. Pre-assembly of the Torus thermal shield is nearly complete at Jefferson Lab. The parts for the vacuum jackets have all arrived and are being welded as much as possible before the coil cold masses arrive from Fermilab. The vendor for the Solenoid magnet has wound 12 of the 26 layers of the practice coil.

13 August 2014

Work on the voltage-tracking regulators for the extraction YA's remains on hold, awaiting restoration of power to the service building. The current transducer for the Hall D leg of the beam envelope limit system has been received. The magnets for the fast-feedback system for the Hall D beamline have been completed. The cavities for the nanoAmp beam position monitor system for the Hall D beamline are being welded and will then be sent out for plating.

6 August 2014

On July 30, DOE convened an Energy Secretary Acquisition Advisory Board (ESAAB) meeting which resulted in the approval of Critical Decision-4A for the 12 GeV CEBAF Upgrade project. This very important milestone marks the completion of the accelerator and civil portions of the project necessary to mark the transition to initial operations of the 12 GeV facility. This decision was supported by the important accelerator commissioning milestones achieved in spring 2014. The attention of the 12 GeV Project Team will now be focused on Hall D beam commissioning this fall, and on completing the physics experimental equipment in Halls B and C by September 2017.

30 July 2014

The Hall D Barrel Calorimeter, Forward Calorimeter, Forward Drift Chamber, Central Drift Chamber and Time of Flight wall, i.e. the five large subsystems of the main spectrometer in Hall D, are all being commissioned in their final positions. The fixed array tagger hodoscope and pair spectrometer detectors are being installed. The detector elements for the tagger microscope and the start counter are being assembled at the vendors' sites, with their arrival expected in August for installation into the hall. Operation of the electronics, the trigger network, and the data transfer from the experiment's digitizers all the way to the data storage silos has been demonstrated, with effort now focused on operating all electronics and data acquisition crates in parallel. Candidates for the thin diamond crystals needed to create the Hall D photon beam have been tested at the CHESS (Cornell High Energy Synchrotron Source) synchrotron light source and shown to have adequately narrow rocking curves. These will be subsequently thinned to 20 microns, as needed for the coherent bremsstrahlung radiator. The repairs to the Hall D helium refrigerator have been completed. The refrigerator plant was restarted and tested, and in parallel the cool-down of the Hall D solenoid magnet also was started. Earlier this week, the refrigerator was connected to the solenoid, and the coil return temperatures are between 8 Kelvin and 11 K.

16 July 2014

The magnet power team has completed all installation and hardware checkout of the box supplies and trim supplies, including those for the synchrotron radiation correction coils on the dipole magnets in arcs 7 through 10. Work on the voltage-tracking regulators for the extraction YA magnets is nearing completion. The frequencies of the cavities for the nanoAmp beam position monitors on the Hall D beamline have been trimmed. The documentation for procurement of the mounting box and thermal blanket are complete. Cabling and digital controls for the fast feedback system on the Hall D beamline are underway.

9 July 2014

The summer scheduled accelerator down work continues, with a major focus on the Utilities Infrastructure Modernization (UIM) project. As the UIM project progresses, there will be several extended outages in both the low-conductivity water and the electrical power delivery throughout the facility. These outages are being closely coordinated with the planned 12 GeV Upgrade work. Hall D is nearing the start of commissioning activities with the recent experimental readiness review held on July 1 and 2. The pre-bid vendor meeting was held for the installation of the Hall C magnet yoke assemblies. This activity will involve heavy material handling and crane lifts. When the work commences, all personnel in the hall will need to be aware of the posted boundaries. The work is expected to be complete by the end of August.

2 July 2014

The concrete shield house and support platform for the Hall C Super High Momentum Spectrometer are being outfitted with electrical, cryogenic and water services in anticipation of arrival of the first of the new superconducting magnets. All the new high-current power supplies have been tested using the magnets of the High Momentum Spectrometer as high-inductance loads. Construction of two of the magnets, the HB dipole and Q1 quadrupole, is now in the latter stages. The thermal shield and cryostat have been added to the Q1 magnet, and sensor and instrumentation work continues in preparation for the cryogenics control reservoir. Addition of the several dozen parts of the thermal shield is underway for the HB magnet, after which the cryostat can be attached. The first production coil for the SHMS dipole magnet is having its last layer wound, and the second production coil has reached the mid-point of its winding. The tooling is on order to fabricate the Q2 and Q3 magnets, with winding planned to begin in September.

25 June 2014

The scope for the 12 GeV Upgrade accelerator DC power subsystem is nearly completed. A handful of 20 Amp trim power supplies need to be installed and checked out on the Hall B beamline (known as 2C) and on the Hall C beamline (known as 3C). The box power supplies for 2C and 3C have been tested into resistive loads. Connections to magnets, Personnel Safety System certification and final tests are taking place this week. The subsystem for Instrumentation and Controls/Safety continues their work on the fast feedback and nano-Amp beam position monitor system for the beamline to the Hall D tagger.

11 June 2014

The summer Scheduled Accelerator Down (SAD) is in full swing, with maintenance activities ongoing in the accelerator areas and across the site. In Hall C, the Super High Momentum Spectrometer shielding work is complete. Hall D is being readied to start the commissioning activities at the completion of the SAD. In the Hall B Torus Cryostat factory, assembly is progressing in preparation for the arrival of magnet coils later this year. In an effort to mitigate potential ergonomic concerns due to static or awkward body positioning during some of the assembly steps, modifications have been made to the set-up and tooling.

4 June 2014

Hall B Update

All sectors of the CLAS12 Forward Time-of-Flight (FTOF) arrays, FTOF1-a and FTOF1-b, and the PreShower Calorimeter (PCAL) have been mounted on the forward carriage in Hall B, connected to the new FADCs, discriminators and high voltage, and have been read out. All of the Region 1 Drift Chambers have been shipped from Idaho State University to Jefferson Lab, with four now ready for installation and two having instrumentation added. All Region 2 Drift Chambers are on site and undergoing final high-voltage testing. Four of the Region 3 Drift Chambers are ready for installation and the fifth is having instrumentation added. The sixth Region 3 Drift Chamber has had all of its wires strung and is having the window fitted in preparation for first testing and conditioning; this completes wire stringing for the Drift Chambers.

Assembly and testing of the CLAS12 Silicon Vertex Tracker (SVT) production modules continues at Fermilab, with over 20 now completed and construction expected to continue until the fall of 2014. A test fit of the SVT modules into their support frame has been performed in the clean room at Jefferson Lab in preparation for assembly of the first three layers of the SVT barrel. The containment vessel for the High Threshold Cerenkov Counter has had the photomultiplier tube supports added and is being readied for mirror installation this fall. All of the coated production mirror segments are on site and tested. For the existing Low Threshold Cerenkov Counter (LTCC), the mirror refurbishment is complete for the first of three types of mirrors and the first batch of the aluminized Lexan strips have arrived from the vendor. The LTCC box modifications and new supports are also underway.

The practice coil for the CLAS12 Torus magnet was sectioned and unfortunately found to have one section that's 70 cm long that was not wetted by the epoxy used to bind the coil turns. Work at Fermilab was re-directed to address this and revise the epoxy impregnation procedure. A second Torus practice coil will be wound, epoxy-impregnated, and then cut apart and examined to verify the new epoxy process before proceeding to further production coil winding. Major parts for the Torus continue to arrive at Jefferson Lab. Pre-assembly of the Torus thermal shields is ongoing, and the first of the vacuum jackets has had all the necessary welding completed. The vendor for the Solenoid magnet has prepared the manufacturing tooling to wind the Solenoid coils and is cleaning the conductor for the Solenoid practice coil, which will be wound starting in mid-June.

28 May 2014

On the evening of May 7, 10.5 GeV beam was delivered to the Hall D tagger dump. This completed the 12 GeV Upgrade Project beam commissioning goals for FY14. More importantly, it sets the stage for detector commissioning in Hall D this fall. Work is progressing on completing the magnet power supply installation and checkout for extraction on passes 1, 2, 4 and 5 and the beamlines to Hall B and Hall C. Final checks of the instrumentation for the Hall D tagger vault are nearly completed. Work continues on the nano-Amp beam position monitor system for the Hall D beamline; procurements have been placed ,including those for the cavity fabrication.

21 May 2014

Accelerator Operations ended last week, marking the start of the summer 2014 Scheduled Accelerator Down (SAD). During the next three months, construction activities will ramp up as the Utilities Infrastructure Maintenance (UIM) project begins. This work addresses needed infrastructure support for operations in the 12 GeV era. In Hall D, installation work is progressing to prepare for the start of commissioning activities at the completion of the SAD. Hall C work continues on the Super High Momentum Spectrometer (SHMS), with electrical and cryogenic services being installed. Shielding work in the SHMS that began in April will be completed at months end, leaving installation of the access flooring to complete.

14 May 2014

The Hall D Barrel Calorimeter, Forward Calorimeter, Forward Drift Chamber, Central Drift Chamber and Time of Flight wall, i.e. the five large subsystems of the main spectrometer in Hall D, have all been installed in their final positions and are being commissioned. The tagger and pair spectrometer magnets have been mapped, and installation work is starting on the fixed array tagger hodoscope and pair spectrometer detectors that accompany them. The detector elements for the tagger microscope and the start counter are being assembled, with arrival at Jefferson Lab expected in the summer. The counting house has been fitted out with racks of readout and trigger electronics, together with the cabling and fiber networks that interconnect them. Operation of the electronics, the trigger network and the data transfer from the experiment’s digitizers all the way to the data storage silos has been demonstrated, with regular tests and tune-up ongoing. An order has been placed for the thin diamond crystals needed to create the Hall D photon beam. These will be graded at a synchrotron light source and selected for subsequent thinning to 20 microns, as needed for the coherent bremsstrahlung radiator.

7 May 2014

On May 3, the first beam was delivered to the front section of the beamline to Hall D, thus demonstrating that all 5.5 passes of the accelerator were functional, and there were no obstructions in the way of the beam. That was done with each linac operating at 550 MeV, and the machine was then scaled up to 950 MeV in each linac to achieve greater than 10 GeV beam after 5.5 passes. Stable 10.5 GeV beam reached the Hall D beamline early this morning (May 7). This significant accomplishment completes a major 12 GeV Project milestone and puts Jefferson Lab one step closer to approval of Critical Decision-4A (Accelerator Project Completion and Start of Operations). It also sets a new energy record for beam from CEBAF. Authorization to put this beam into the Hall D tagger vault is being evaluated by the Chair of the Accelerator Readiness Review Committee, Manager of the DOE Site Office, and the Lab Director. When the authorization is given, the Head of Accelerator Operations and the commissioning team will send the beam down the new beamline into the Hall D tagger vault for the first time.

30 April 2014

The Hall D segment of the Personnel Safety System has been certified. The Hall D tagger dump water system is operational, with checks of the controls underway. The beamline to the dump is under vacuum. Checks of the beam diagnostics are underway.

During initial in-tunnel operation of the ZA septa magnets in the west end of the accelerator on April 15, an electrical ground-fault occurred. This led to burn-through of a magnet coil and vacuum chamber, which permitted water to flood the beamline vacuum space in the region. An investigation determined that the ground-fault was caused by debris on the magnet between the coil and the vacuum chamber, likely introduced after installation in the tunnel. The cause of the burn-through was determined to be incorrect vendor assembly of the associated new box power supply, which made it possible for large ground currents to flow without tripping the detection circuit. The ZA magnet has been repaired and re-installed. Modifications have been done to that magnet and all similar ones to prevent debris from getting to critical locations. All new box power supplies have been modified to correct the assembly error. The magnet that failed has now been operated at the required setting for delivering 10 GeV beam to the Hall D beamline.

23 April 2014

Hall C continues to install shielding and other components in the Super High Momentum Spectrometer detector, as well as cryogenic connections to the SHMS carriage. Installation and commissioning work continues in Hall D, with all five major detectors now installed. The Tagger area is being prepared to receive beam with energy greater than 10 GeV to meet 12 GeV Upgrade project milestones. The goal is to complete Hot Checkout to permit 5.5-pass, tune beam to this area before the summer accelerator shutdown in May.

16 April 2014

At the request of DOE's Office of Nuclear Physics, Stephen Meador, Acting Director of the Office of Project Assessment in DOE's Office of Science, convened a team of 16 experts and eight observers in an Independent Project Review of the 12 GeV CEBAF Upgrade Project at Jefferson Lab April 8-10. The purpose of the review was to assess all aspects of the project, including technical, cost, schedule, management and ES&H. The review team provided valuable feedback in all areas and a total of 12 specific recommendations in the areas of superconducting magnets and project management. The committee congratulated the 12 GeV Team on the significant progress made in the accelerator and experimental hall detectors, as well as the project’s safety record and lab implementation of the Accelerator Readiness Review and commissioning processes.

9 April 2014

The concrete shield house for the Hall C Super High Momentum Spectrometer has been constructed on the new support carriage and is being outfitted with specialized boron carbide and lead shielding panels. Work continues to outfit the platform itself with electrical, cryogenic and other services in anticipation of the arrival of the new magnets. The first two new magnets, the HB dipole and Q1 quadrupole, are now in the last stages of construction of the cold masses, which includes final welding of the helium vessels. Parts for the LN2 shield for the HB dipole have been test fit, and the vacuum vessel and support links for HB are ready. The thermal shield for Q1 has been delivered to the magnet vendor and will be attached next. The first double-pancake of the production coil for the Dipole magnet has been wound. Two more double pancakes are required to complete the first full Dipole coil. The vendor’s second winding station is being readied to start winding of the second Dipole coil in parallel with continuing the first coil. Very similar tooling and techniques will be used afterwards by the same vendor to fabricate the Q2 and Q3 magnets starting in the summer.

2 April 2014

All of the beam transport scope has been completed, with the exception of final leak checks in the Hall D tagger vault. All of the 20 Amp trim supplies for 5.5-pass beam have been checked and installed. Status of box power supplies: RSEP9 and arc 7 are ready to be certified for the Personnel Safety System and hooked up to the dipole magnets; arc 9 has been received and is being uncrated; and RSEP8 and arc 8 are nearly ready for PSS certification. The PSS system is ready for certification of the Hall D branch. The stripline beam-position-monitor electronics are being installed on the beamline to Hall D. A 4.8 GeV beam has been to the end of arc 6, and 3-pass 4.8 GeV beam has been sent to the Hall A dump. 

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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