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12 GeV Updates

1 July 2015

One of the last civil construction tasks for the 12 GeV CEBAF Upgrade is the accelerator tunnel air conditioning. Under this contract, installation of the chilled water piping in the tunnel is now complete. Pressure testing of piping segments has begun. With successful pressure tests, the chilled water piping is insulated. Installation of fire sprinkler pipe in the tunnel arcs continues.

24 June 2015

The detector systems in the Hall C Super High Momentum Spectrometer have seen significant progress with the installation of both the S1XY and S2XY scintillator and quartz hodoscopes. These detectors and their frames were built by university staff and students at James Madison University, North Carolina Agricultural and Technical State University, and The College of William and Mary through funding from the National Science Foundation. Installation of the large number of cables that connect to all of the SHMS detectors is now nearly complete, as well. Mirrors for the Noble Gas Cerenkov counter have been coated at CERN and are now safely back at the University of Virginia.

A major milestone for the SHMS dipole magnet construction was passed with the successful collaring of the magnet's coil assembly. Twenty-four precisely-machined aluminum rings, about three feet in diameter and six inches thick, were heated to 300° F to make them expand enough to slip over the twelve-foot long cylindrical coil. Months of planning and rehearsal paid off when all of the 'collars' were fitted on the coil in one eight-hour shift, as required. The same process will be used to collar the final two SHMS magnets in the next several weeks. Checkout of the HB and Q1 magnet systems continues in Hall C.

10 June 2015

Hall B - CLAS12 Magnets
The seventh Torus Coil (i.e. first of two spare coils) arrived in its coil case from FNAL on May 28 and was prepared for testing at LN2 temperatures. The sixth coil has completed this test and has had its first multi-layer insulation (4K) added followed by the thermal shield. The fifth coil has been welded into its cryostat, moved to Hall B, and mounted on the cold hub as of June 5.

Splices of the conductor running between coils have been completed inside three (of 6) supporting hex beams. The required instrumentation and insulation has been added in preparation for the addition of thermal shields and vacuum jackets later this year. The vendor contracted to build the distribution can for the cryogenics for both the Torus and Solenoid magnets has received the materials and is proceeding with assembly. The fabrication of the cryogenics control can, which will serve as the Torus Service Tower, has commenced in parallel at Jefferson Lab. The power supplies for the two magnets were delivered and have been located on the space-frame platform upstream of the experiment in preparation for running power and water to them. Fabrication of the instrumentation chassis and racks, together with the cable harnesses and needed firmware, is also progressing.

The vendor for the Solenoid magnet has finished winding the second of the five major coils needed for that magnet and expects to complete all windings by early Fall.

3 June 2015

On the Tunnel Air Conditioning contract, the chillers were delivered and set on the concrete pads on May 19. Warwick Plumbing & Heating is installing the piping to the chillers and the electrical subcontractor, Carr Electric, is running power to the chillers. Work in the tunnel resumed with the start of the summer accelerator shutdown. Warwick Plumbing & Heating is installing chilled water pipe in the west arc and the controls subcontractor, Dominion Electric, is installing conduit.

20 May 2015

Hall C: Connection of the Hall C SHMS Horizontal Bend (HB) magnet to all of its services was completed and the magnet was successfully cooled-down to liquid-helium temperature (4.2K). A challenging aspect of this magnet is that the distance between helium-temperature and room-temperature pieces is only a few millimeters in some places. The successful cool-down shows that this challenge has been met. During initial tests, the magnet was operated successfully at 10 percent of its eventual operating current. Careful engineering studies are being performed in preparation for full-current testing. The vendor building the Q2, Q3, and Dipole magnets is half-way through a series of practice tests that will conclude with shrinking the large metal collars onto the dipole magnet coils.

The new support system for the massive steel yoke of the SHMS Q2 magnet has been installed, and progress has been made towards completion of the gas system of the Heavy Gas Cerenkov detector. Installation of the large number of signal and high-voltage cables for all of the SHMS detectors continues.

13 May 2015

The summer accelerator shutdown period will begin in earnest on May 18. During this time, the remaining 12 GeV Upgrade civil construction work will be completed, mainly installation of the tunnel air conditioning.  Installation of spectrometer magnets, detectors, and support services continues in both Halls B and C.

6 May 2015

Hall B: The first two regions of the Silicon Vertex Tracker (SVT) for CLAS12 in Hall B have been mounted on the cooling plate in the clean room at Jefferson Lab and are undergoing testing and burn-in. The separate cooling plate and support structure for SVT region 4 is also complete and is being assembled in preparation for mounting. The magnetic shielding materials for the Central Time-of-Flight (CTOF) have arrived and been checked. The CTOF slats have all had their outer light-tight wrapping added, and photomultiplier tube (PMT) and magnetic shield mounting has started. The large mirror for the High Threshold Cerenkov Counter (HTCC) has been assembled, checked and mounted in the large containment vessel. A gimbal-mounted laser is being used to scan the HTCC mirror segments and check the spatial and angular positioning of the 48 mounts for PMTs. The work to refurbish the boxes for the Low Threshold Cerenkov Counter is nearing completion and the mounting of components, including the Winston Cones, PMTs, bases and cabling, inside the first box has started in the clean tent. Calibration work for the Forward Time-Of-Flight, Pre-Shower Calorimeter and Electromagnetic Calorimeter already mounted on the forward carriage is proceeding steadily.

29 April 2015

Work continues on the few remaining areas of civil construction for the 12 GeV CEBAF Upgrade project. On the accelerator tunnel air conditioning contract, Warwick Plumbing & Heating continues exterior work in preparation for the chillers to be delivered in May and the summer accelerator shutdown to commence. The concrete slabs for the chillers are complete. Electrical work to power the chillers is near complete. The contractor started the exterior chilled water piping that will run from the chillers to the tunnel enclosure.

22 April 2015

The giant, concrete shield doors on the Hall C Super High Momentum Spectrometer (SHMS) have been outfitted with drive motors so that they may easily be opened and closed. Inside the shield house, the Heavy Gas Cerenkov (HGC) counter is now in position and connected to its data-acquisition electronics. Researchers from the University of Regina, who built the detector, obtained much of the funding for it through a grant from the Canadian government. The remainder of the detector was paid for by the 12 GeV Upgrade Project, as were the JLab-designed alignment, gas, and electronic systems.

The SHMS Q1 magnet, which arrived in January, has been cooled to liquid-helium temperature and successfully tested to its full design field. Connection of the HB magnet to its control, power, and cryogenic services is continuing on schedule. Cool-down testing is expected to begin soon, and power tests will follow.

The vendor of the final three SHMS magnets is making good progress. All coil winding has been completed, and only two of the 10 sub-coils remain to be impregnated with epoxy. The two sub-coils of the Dipole magnet have been glued together to form a cylindrical assembly, and the outer surface of this has been shaved down to make a nearly-perfect cylinder. The next step is to heat large aluminum rings and slip them over the coil so that when they cool and contract they will tightly squeeze the coil and hold the conductors in place.

8 April 2015

The Physics Division conducted an Equipment Readiness Review (ERR) for the Hall C Horizontal Bend (HB) magnet on March 25. The ERR is an essential part of the process for safely testing and commissioning each superconducting magnet being built as part of the 12 GeV CEBAF Upgrade project. Following the successful review, the HB magnet was placed on the Super High Momentum Spectrometer (SHMS) carriage on Tuesday, March 31, and cryogenic connections are now underway. In the area of 12 GeV civil construction, above-ground work for the tunnel air conditioning has been hampered due to the weather, but work is progressing.

1 April 2015

The fifth of six coils needed for the CLAS12 torus magnet arrived in its coil case from Fermilab on March 21 and was prepared for testing at liquid nitrogen temperatures. The fourth coil has completed this test at Jefferson Lab and is being readied for adding layers of multi-layer insulation (MLI), to be followed by the thermal shield, more MLI and its cryostat. The third coil has been placed into its cryostat which is now being welded, the second has been moved to Hall B in preparation for mounting, and the first coil is now mounted in place on the cold hub for the torus in Hall B.

The vendor for the CLAS12 solenoid magnet is in production with the start of winding for the first of five major coils. Winding is expected to complete in Fall 2015. A contract has been placed to build the distribution can for the cryogenics for both the CLAS12 torus and solenoid magnets with delivery expected in October 2015. The vendor for the power supplies for the magnets has finished construction and is putting them through a series of in-factory tests before shipment to Jefferson Lab.

25 March 2015

On the Accelerator Tunnel air conditioning contract, Warwick Plumbing & Heating is preparing the concrete slabs for the chillers at grade level near each of the arcs. The chillers are scheduled for delivery in May. To coordinate with accelerator operations and the chiller delivery schedule, minor site preparation was planned for the months of March and April.

18 March 2015

The second superconducting magnet for the new Hall C Super High Momentum Spectrometer (SHMS) was delivered on March 6. The HB (Horizontal-Bend) magnet is the end product of a program that started in 2006 as an R&D collaboration between Jefferson Lab and Michigan State University. Construction began in 2010 and has involved staff of the National Superconducting Cyclotron Laboratory and the Facility for Rare Isotope Beams, as well as MSU. The HB Magnet must be compact but provide a high magnetic field, so that particles scattered at very small angles from the electron beam may be captured and analyzed by the SHMS. It uses saddle-shaped coils wound using reshaped SSC superconducting cable. The coils are tightly enclosed within a thick, heavily-welded stainless-steel H-shaped box. It must resist the 180-ton force that the coils will exert on it when they are fully energized. The HB Magnet is currently passing a series of incoming inspections on the floor of Hall C. It will be put in place on the SHMS carriage in the coming weeks.

At the request of DOE's Office of Nuclear Physics, Stephen Meador, Director of the Office of Project Assessment in DOE's Office of Science, convened a team of seven experts and five observers in an Independent Project Review of the 12 GeV CEBAF Upgrade Project held at Jefferson Lab on March 12. This review was to follow up on remaining questions from the November 2014 review. In the closeout, the committee found that the team had appropriately addressed recommendations from previous reviews. Further, while the superconducting magnets present challenges - with continued emphasis on process control, QA and vendor oversight - the project is positioned to be completed within the established cost and schedule performance baseline.

25 February 2015

The first 12 GeV Hall C magnet, Q1, which arrived in January, has been installed on the Super High Momentum Spectrometer (SHMS) carriage and connected to its cryogenic, power, and control systems. Following a checkout of those services, this superconducting magnet is now being cooled-down in preparation for its final acceptance tests. Close on its heels is the Horizontal Bend (HB) magnet, which is in its final week of construction at Michigan State University. The remaining three SHMS magnets are making steady progress, with the two coils for the dipole having been bonded together, and the final two (of eight) Q2 and Q3 coils now on the winding machines. On the SHMS, the calorimeters have been installed, and now the stands and frames for the remaining detectors have been trial-fitted in the shield house to assure that detector installations may proceed smoothly. Cables for the detectors are being installed now, as are the floor scales that provide experimenters with a precise measurement of the spectrometer angle.

18 February 2015

The 66 modules needed for all four regions of the Silicon Vertex Tracker (SVT) for CLAS12 have been completed and tested at Fermilab and were then transferred to Jefferson Lab. The cooling plate and support structure to mount the first three of the four regions of the SVT are nearing completion, after which assembly will start in the large clean room in the Experimental Equipment Lab. The magnetic shielding materials for the Central Time-of-Flight (CTOF) have arrived and are being checked. The CTOF slats are glued together and are in the process of having the outer light-tight wrapping added, after which photomultiplier tube mounting and testing will start. The large mirror for the High Threshold Cerenkov Counter (HTCC) has been assembled and is being checked. The large containment vessel for the HTCC has been assembled and stood up on edge in preparation for a test mounting of the mirror on its support ring. The work to refurbish the boxes for the Low Threshold Cerenkov Counter, after its long service in CLAS, is nearing completion, and the mounting of components inside the first box has started in the clean tent. Calibration work for the detectors already mounted on the Forward Carriage (Forward Time-of-Flight, Preshower Calorimeter, and Electromagnetic Calorimeter) has proceeded steadily, and the calibration plans for the entire CLAS12 were recently reviewed.

11 February 2015

The accelerator tunnel air conditioning contract vendor, Warwick Plumbing & Heating, made excellent progress during the January scheduled accelerator down (SAD) period. All of the 132 chilled beams are installed, and the majority of the chilled water and fire protection piping is also installed. The remaining piping work in the accelerator tunnel will be completed during the Summer 2015 SAD. Also during the January SAD, Warwick connected and commissioned the backup cooling towers for the North and South Access low-conductivity water systems. These towers, along with the previously installed 12 GeV cooling towers at maximum capacity, support accelerator operations during the demolition of the old cooling towers under the Utilities Infrastructure Modernization (UIM) project.

28 January 2015

The Physic Division held an equipment readiness review of the Super High Momentum Spectrometer Q1 magnet on Jan. 21. No major issues were identified and cooldown of the Q1 magnet will soon commence. The final 12 GeV Upgrade civil construction activity (tunnel air conditioning) is well underway. The related work in the tunnel involved drilling into the overhead to install hangers for the chill beams and associated piping. The subcontractor used a drilling tool for the overhead work. This apparatus allowed the subcontractor to apply an engineered solution to eliminate the ergonomic stresses to the workers, and the attached HEPA vacuum provided local capture ventilation for silica generated during the drilling. During the monthly progress meeting, the feedback from the subcontractor was that the tooling provided the added benefit of significantly increased efficiency for the task.

21 January 2015

The first of seven superconducting spectrometer magnets being built as part of the 12 GeV CEBAF Upgrade project has been delivered to Jefferson Lab. The first quadrupole magnet (Q1) for the Super High Momentum Spectrometer in Hall C is a clone of the High Momentum Spectrometer Q1 magnet; a cold iron design with a 40 cm warm bore, 11 GeV/c performance and a gradient of 7.9 T/m. It was built by Scientific Magnetics, Inc., in the UK and arrived on site on Jan. 13. Acceptance tests are underway. The Physics Division is convening an equipment readiness review for the new Q1 on Jan. 21 to assess the readiness for full, safe operation.

 

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