12 GeV Updates
December 20, 2006
One thrust of the 12 GeV Physics R&D program focuses on producing a tagged polarized photon beam for Hall D experiments. A critical component of this process is an ultra-thin wafer of diamond crystal, which produces polarized photons when the electron beam passes through it. Wafers of 50 micron thicknesses have been successfully used for experiments previously; however, the 20 micron wafers needed for Hall D consistently show problems in aligning the desired crystal planes with the incident electron beam. Recent Hall D R&D efforts have used X-ray diffraction to study the 20 micron diamond crystals. Wafers were sliced from a near-perfect diamond and then polished down to 20 microns. In November, members of the Hall D/GlueX photon beam working group took X-ray diffraction images of the wafers at the Cornell High Energy Synchrotron Source (CHESS). These images showed a pronounced warping pattern extending across the entire face of the 5 x 5 mm2 crystal. The measurements are a first step toward understanding how to mount these fragile crystals in the electron beam without distorting their shape, thus improving their performance.
December 13, 2006
On Dec. 4, pre-brief material was provided to the review committee for the 12 GeV Upgrade Federal Project Director-led Project Status Review. This review is taking place throughout December and January to evaluate preparations for the Critical Decision 2 (CD-2) approval process scheduled for next summer. The on-site portion will be held at JLab on Jan. 9 and 10, 2007. The pre-brief material consisted of 16 folders, including documents such as a resource-loaded schedule, timeline for reaching CD-2, review reports, design reports, value engineering reports, project plans, CD-1 documents, and review recommendation trackers. The on-site review will be followed by an Office of Science Office of Project Assessment (SC OPA) and DOE Office of Nuclear Physics (DOE-NP) assessment of CD-2 preparations for 12 GeV on Jan. 30, 2007.
November 29, 2006
The 60% design submittal for the Central Helium Liquefier (CHL) Addition (conventional facilities) was received from the architect-engineering (A-E) firm on Nov. 27. Copies of the submittal have been distributed to Facilities & Logistics, the Cryogenics Group, ESH&Q Division and IT Division for internal design and safety review. A meeting to discuss the review comments with the A-E's design team is scheduled for Dec. 18.
November 15, 2006
The 12 GeV Upgrade Accelerator Arc Magnet Review was held Nov. 8 at JLab. Two safety experts and two magnet experts traveled from three national laboratories and NASA's Langley Research Center to critique possible issues with safety and long-term accelerator reliability/performance related to the increased temperatures of some arc magnets and tunnel air. Formal talks were presented to the review panel by members of the 12 GeV Project Team, CASA, and Facilities Management. The committee was impressed by the baseline approach for the accelerator and the conventional facilities aspects of the project that was developed to assure safe and reliable long-term operations. The committee concluded that following implementation of three small enhancements, the present plan responsibly addresses all safety and reliability issues.
October 25, 2006
Design effort on the conventional facilities to support the 12 GeV CEBAF Upgrade continues to progress. On Oct. 10, JLab Facilities Management & Logistics personnel initiated the in-house design of the North and South Access Building Additions. On Oct. 13, Hayes, Saey, Mattern & Mattern, an architect-engineering (A-E) firm of Roanoke, VA, was given the notice to proceed for the 60% design of the Hall D Complex.
October 18, 2006
The 12 GeV Upgrade Accelerator Arc Magnet Review will take place Oct 25 at JLab. This review is the next in a series of major system design reviews in preparation for Critical Decision Two in Summer 2007.
October 4, 2006
The 12 GeV Upgrade Conceptual Design and Safety Review of Superconducting Magnets was held Sept. 26-28 at Jefferson Lab. Three expert reviewers evaluated the conceptual design of the seven new superconducting magnets planned for the upgrades of Halls B and C. A total of fifteen structured presentations were made to the committee members. While the committee felt that no issues or formal recommendations were necessary, they provided much insight through many detailed comments and suggestions, both in the presentation sessions and in their closeout. This evaluation and guidance will be very beneficial in guiding the design teams in their preparations for the CD-2 reviews in 2007.
Jefferson Lab is pleased to announce the successful conclusion to our year-long international search for a Hall D Group Leader. Dr. Elke Aschenauer has accepted the position and will be joining the Laboratory in early December. More »
September 27, 2006
The first digital self-excited loop (SEL) for radiofrequency (rf) controls has been developed as part of the 12 GeV R&D. The SEL is of interest to the 12 GeV Project, because it can energize a cavity even if it is not on resonance. Use of an SEL would thus eliminate the cavity turn-on challenge created by the large Lorentz-force detuning seen with cavities operating at the gradients planned for 12 GeV. The demonstrator has been able to achieve phase control in closed loop over a limited detuning range during this portion of the R&D work. Further development is planned to demonstrate the final phase and amplitude control specifications for 12 GeV.
September 21, 2006
The 12 GeV Upgrade Cryomodule Design and Cryomodule/Cryogenics Failure-Mode Review was held Sept. 6-7 at Jefferson Lab. The review committee was impressed with the development of the cryomodule design and good use of JLab's experience with the original CEBAF cryomodules and the more recent SNS cryomodules. The review committee validated that the design changes following the testing of the most recent high-performance cryomodule (Renascence) are conservative and should meet the performance requirements. Constructive recommendations were made for the next phase of testing (known as the "cryomodule test"), and the failure-mode analysis was deemed complete and well thought out for this stage of the project.
The 12 GeV Upgrade Project Conceptual Design and Safety Review of Superconducting Magnets will take place Sept. 26-28 at JLab. This review is the next in a series of major system design reviews as part of the preparation for Critical Decision 2 in Summer 2007.
September 13, 2006
An independent value engineering (VE) study is being performed on the 12 GeV Upgrade CHL Addition (conventional facilities) by Dills, Ainscough, and Duff of Virginia Beach. The CHL Addition includes a building addition on the west side of the existing CHL building (to house compressors), new cooling towers, and two new, 5-megawatt electrical unit substations. The VE report is due Sept. 18 with a presentation to 12 GeV Project Team members the week of Sept. 25. The VE Team, a team of experienced multi-disciplined professionals, is tasked with reviewing the preliminary design to identify alternatives to meeting the design requirements with the greatest potential for cost savings and project enhancement. The preliminary design was developed by Facilities Management personnel utilizing record drawings from the original construction and previous additions to the CHL.
September 6, 2006
The 12 GeV Upgrade Cryomodule Design and Cryomodule/Cryogenics Failure-Mode Review will take place Sept. 6-7 at Jefferson Lab. This review is the next in a series of major system design reviews as part of the preparation for Critical Decision 2 in Summer 2007.
August 16, 2006
Detector R&D for the 12 GeV Upgrade continues. Three undergraduate students, two from California State University and one from Rensselaer Polytechnic Institute, worked this summer with a Hall B staff scientist on the CLAS12 High Threshold Cerenkov Counter (HTCC) R&D. They developed a new technique to build the ultra-lightweight HTCC mirrors without degrading the optically reflective surface ("touch-free technology") and with no residual deformation of the mirror substrate, both of which are critically important to the production of the final mirrors. This new technique will also be of direct benefit to the development of the Hall D Cerenkov detector mirrors.
July 19, 2006
An internal design and safety review of the architect-engineer's (A-E) 35% design submittal for the Hall D conventional facilities was held July 12-13. Several 12 GeV Upgrade project team members, Facilities Management personnel, and personnel responsible for equipment that will be housed in the Hall D complex (both accelerator and experimental systems) met with the A-E representatives to clarify the design requirements and the JLab comments on the preliminary design package. Based on these discussions, the review comments will be finalized for incorporation into the next design submittal by the A-E. Concurrently with this review, an independent value engineering (VE) workshop was held on the Hall D civil construction. The VE was performed by a team of experienced multi-disciplined professionals. On the last day of the workshop, the VE Team presented to Jefferson Lab members a preliminary list of potential design alternatives for the Hall D Complex. The final VE Report is anticipated by mid-August.
July 12, 2006
Daniel Lehman, Director of the Office of Project Assessment in the DOE Office of Science, led a team of 16 experts in the DOE Office of Science Project Status Review of the 12 GeV CEBAF Upgrade at Jefferson Lab June 27-28. The project team received high marks for the excellent progress in both R&D and furthering the development of the Conceptual Design; there were additional high marks for the detailed project plan which leads up to Critical Decision 2 (CD-2) in Summer 2007. CD-2 completes the preliminary design phase and is the point at which the cost and schedule baselines are established. The review committee made several constructive recommendations for further developing the project plan. DOE/NP's commitment to the success of the 12 GeV Upgrade was demonstrated by the announcement of a follow-on review, planned for the end of 2006, to verify that the planning is on track for a successful CD-2 approval.
June 21, 2006
The Hall B Silicon Vertex Tracker data acquisition board prototype has been received and hardware-tested as part of the 12 GeV R&D program. This board, which was designed at Jefferson Lab, is capable of reading out over 15,000 data channels from a silicon microstrip detector. Detectors of this type are planned for use in a vertex detector for the 12 GeV version of CLAS called CLAS12. The software for the complete test of the board is currently under development.
June 14, 2006
Tests of the new digital Low-Level Radio Frequency controls (LLRF) were performed using a cavity in the SL21 cryomodule in CEBAF. Phase and amplitude control specifications were met with the cavity operating at 16.7 megavolts per meter (MV/m), which is the highest gradient available for any cavity in a cryomodule at JLab. In addition, tests of the fast ramping algorithm, which uses the piezo-electric component of the cavity tuner, demonstrated the system's ability to reach 13 MV/m less than one second after starting from zero.
May 31, 2006
The Hall B CLAS12 High-Threshold Cerenkov Counter (HTCC) prototyping project is progressing well. This effort is one of 15 R&D projects for the Experimental Equipment component of the 12 GeV Project this fiscal year. The main focus is to develop new techniques for fabrication of large-area, front-faced mirrors that are ultra-lightweight and which conform precisely to the required 3-D shape. The designs of the prototype mirror and needed tooling have been completed, and the first few reflective Mylar films have been thermally molded. The films have been demonstrated to be stress-free and stable, and they fit well to their elliptically shaped support substrate. The next step is to establish a gluing process to permanently mount the reflective films without significantly increasing mass or inducing distortion.
May 24, 2006
The Center for Advanced Studies of Accelerators (CASA) group continues to study important aspects of the 12 GeV machine and beam optics. Field quality specifications for new and modified magnets have been derived analytically and verified via numerical simulations. A successful test of the 12 GeV optics was performed on the 6 GeV machine in December 2005. Comprehensive particle tracking studies of the beam properties continue using the updated magnet specifications and validated optics. Tolerances on alignment and current settings as well as the impact of synchrotron radiation are being explored as core parts of the ongoing studies.
May 17, 2006
A modified conceptual design for the Hall C Super High Momentum Spectrometer (SHMS) has been developed. The modified design replaces one large, complex superconducting magnet with two separate magnets of a much simpler and more conventional design. The new system concept has now been tested using particle tracking software. With the addition of a small horizontal bending magnet, the final system achieves about twice the solid angle and reduces technical risk for similar estimated cost as the previous conceptual design. A request for statements of vendor interest for the construction of these magnets will be sent out this week.
May 10, 2006
The 12 GeV Upgrade Accelerator R&D work continues. Measurements of an arc magnet to validate the numerical modeling are progressing well. The digital LLRF (low level radiofrequency) controls tests have demonstrated that the new control system has the ability to energize a cavity within 100 msec while holding it on resonance. The optimization of the endgroup design for the 12 GeV cryomodule cavities has begun.
May 03, 2006
Dennis Kovar, Associate Director of the Office of Science for Nuclear Physics, has requested that Daniel Lehman, Director of the Office of Project Assessment, organize and lead an Office of Science Project Status Review of the 12 GeV CEBAF Upgrade Project at Jefferson Lab June 27-28. The purpose of this review is to assess the progress over the last year of the project and associated plans - technical, cost, schedule, management, risk and Environment, Safety and Health (ES&H). The 12 GeV CEBAF Upgrade project was awarded Critical Decision One (CD-1) approval in February 2006.
April 13, 2006
Facilities Management personnel are finalizing the advanced conceptual design of the Central Helium Liquefier (CHL) Addition to support operation of the new CHL #2 to be built as part of the 12 GeV Upgrade. CHL #2 will approximately double the existing cryogenics plant capacity. The planned conventional facilities include a building addition on the west side of the existing building (to house compressors), new cooling towers, and two new 5-megawatt electrical unit substations. Architectural and structural features of the building addition will match the existing building.
March 29, 2006
R&D activities for the 12 GeV Accelerator Systems are proceeding. Of particular note recently is the start of the next round of testing of the new digital Low-Level Radiofrequency (RF) Control system. The testing will use the FEL03 cryomodule until May and then shift to using the SL21 cryomodule in CEBAF to permit testing at significantly higher gradients. Additionally, assembly of the dipole magnet, which will be used for verifying the detailed computer modeling of the new beam transport magnets, has been completed.
March 22, 2006
Now that the CD-1 approval for the 12 GeV Upgrade project has been granted, the very first Program Advisory Committee (PAC) meeting for 12 GeV experiments has been scheduled. While previous PACs have broadly surveyed the upgrade science topics several times, in August PAC 30 will evaluate specific experiment proposals and Letters of Intent. The special focus for this summer's PAC will be on proposals in which the proposing scientists and institutions intend to contribute significantly to the construction of the 12 GeV Upgrade project base equipment. Many JLab user groups have already begun developing proposals in anticipation of this occasion. To see the PAC 30 Call for Proposals, visit: http://www.jlab.org/exp_prog/PACpage/PAC30/PAC30.html
March 01, 2006
During his visit to JLab last week, U.S. Secretary of Energy Samuel W. Bodman made two exciting announcements: the Lab has received CD-1 approval for the 12 GeV Upgrade and President Bush's FY07 budget request includes $7 million for the next phase of the project. The approval required that a number of prerequisites be met, including a verification of the mission need for the upgrade, a full Conceptual Design Report, an acquisition plan and a preliminary hazard analysis. CD-1 is the second of five necessary approvals in DOE's project acquisition process, and it allows the Lab to begin Project Engineering and Design. The 12 GeV Upgrade project will be a $225-$300 million investment in the facility and will ensure that JLab continues its world-class scientific program.
February 15, 2006
The pre-design conference for the Hall D conventional facilities was held Feb. 2-3 at JLab. The first day included a series of presentations by Facilities Management personnel to the architect-engineering (A-E) design firm on the conceptual design and a tour of JLab facilities. The second day, the A-E personnel interviewed 12 GeV Project Team members and other key technical personnel about the equipment planned for Hall D to establish design requirements and utility needs. The A-E firm is Hayes, Saey, Mattern, & Mattern (HSMM) of Roanoke, Va.
February 08, 2006
The data collection and theoretical calculations for 12 GeV Upgrade civil research and design (R&D) on natural convection air conditioning for the accelerator arcs are complete. This R&D addressed two risk elements: technical and cost. The R&D simulation determined that a natural convection air conditioning system will cool the heat load from the tunnel during 12 GeV operations and identified the optimum fin design for the cooling coils. The optimum cooling coil design requires custom-manufactured coils versus a standard "off-the-shelf" coil design. The draft R&D Report is under internal review and will be submitted to DOE by the end of February.
January 25, 2006
A review of the Hall D Tagger and Photon Beamline was held Jan. 23-24 at JLab. This review was convened by the 12 GeV Project Management Team. A small committee of experts from Europe and the U.S. critiqued the conceptual designs for the tagging magnet, vacuum box, hodoscope systems, and other components of the Hall D Photon Beamline. Formal talks were presented by members of the GlueX collaboration, who traveled to JLab from as far away as Scotland for the review. The committee was impressed by the quality and completeness of the design and found no significant problems, but committee members did offer a number of valuable suggestions for future improvements.