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12 GeV Updates

December 21, 2005

A 1497 MHz power source with 13 kilowatts (kW) of output power is required for each cavity in the 12 GeV Upgrade cryomodules. None are commercially available at this time. An earlier brief reported that a firm was designing and prototyping a unit that would meet 12 GeV requirements through a Small Business Innovation Research (SBIR) grant from DOE. The initial round of testing on the prototype has been completed with very good results. The unit operated at 16 kW in continuous wave (cw) mode and has an efficiency of >50%. Some adjustments will be made for optimal performance, and then the unit will be shipped to JLab for intensive testing.

November 16, 2005

A 1497 MHz power source with 13 kilowatts (kW) of output power is required for each cavity in the 12 GeV Upgrade cryomodules. None are commercially available at this time. A commercial firm has received Small Business Innovation Research (SBIR) grants from DOE over the last three years to design and prototype a unit which would meet the 12 GeV requirements. A prototype has been developed, and the company started testing at their facility in the first week of November.

November 02, 2005

A Hall D/GlueX Software Workshop was held at JLab Oct. 21-22. The main goal of the workshop was to develop a top-level framework for reconstruction software for the experiment and to gain general consensus on the basic format for the individual detector packages. Approximately 25 people participated in the workshop. The focus was on three specific areas for each detector subsystem: the definition of software data "factories," calibration procedures and monitoring. The workshop successfully identified ways of making the individual packages consistent with one another and produced a plan for a coherent reconstruction package.

October 27, 2005

Initial data has been taken from the test chamber for the 12 GeV civil R&D project on the natural convection air conditioning. Adjustments to the chilled water temperature were necessary to simulate anticipated conditions in the accelerator tunnel. Two different configured finned coils are mounted in the test chamber for comparison and analysis of data. Currently, data is being collected from the first coil; water flow, temperature and power are being measured.

October 12, 2005

One of the ongoing R&D projects for the 12 GeV Upgrade is to study the technical issues associated with a particle detector called the Silicon Vertex Tracker (SVT) that will be part of the upgraded Hall B. Following initial bench tests, data from a prototype of the SVT were taken this past summer in a beam test that was parasitic to the ongoing Hall B program. Many useful observations resulted that will benefit the design of the final, more complex, system. In September, members of the SVT development team visited Fermilab, a potential collaborative partner in this detector effort, to discuss lessons learned and next steps.

September 28, 2005

Initial testing of JLab's new digital low-level RF (LLRF) controls was carried out using Renascence, third in a series of prototype high-performance cryomodules at CEBAF. The system demonstrated, at low power, the ability to meet the specifications for phase and amplitude control required for 12 GeV. The planned September testing was temporarily suspended due to unexpected thermal behavior in some of Renascence's 2 Kelvin components. Testing of Renascence and the 12 GeV LLRF system is expected to resume next week.

September 21, 2005

The Test Chamber for the 12 GeV civil R&D on natural convection air conditioning for the accelerator arcs has been constructed in an unused utility tunnel in the Test Lab basement. The cooling capacity of finned coils with respect to the heating surface will be measured as a function of coil orientation and position. Facilities Management will begin taking data in October. The project team is following up on recommendations received during the DOE Independent Project Review held July 12-14, 2005, and the CD-1 project documents are being finalized.

September 07, 2005

Prototyping of the Hall D drift chambers is progressing well. Fabrication and testing of a small prototype of the forward drift chamber (FDC) is proceeding at JLab. Cosmic-ray muons are being used to test the ability of the FDC prototype to reconstruct high-energy charged particle tracks with high precision. The measurements of the charge collected on the cathode planes have been used to test the position resolution of the chamber, with very good results. Additional measurements have also been performed to determine timing calibrations using the JLab-designed F1 Time-to-Digital Converter (TDC) modules.

The report from the DOE Review of the Science of the 12 GeV Upgrade project, held April 6-8, 2005, has been posted on the CEBAF @ 12 GeV web site at: