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J. Cook, D. Helms, W. Skinner

Division (M7), FEL Coordination Group

F. Dylla

IR Demo Project Weekly Report, July 19-24, 1998

July 24, 1998

Management

This week was devoted to hardware checkout activities in preparation for the up-coming runs to commission the recirculation loop and push toward kW laser power. Highlights for the week include: (1) cathode processing and HV processing of the photogun; (2) check-out of the MPS hardware and recirculation loop transport elements.

On Tuesday, July 21 the Project Monthly Report for June 1998 was distributed to the DOE and Navy program offices. A smooth close-out of the contract under the current (FY97-98) Navy- DOE Memorandum of Agreement is expected by the end of the fiscal year. A draft extension of the contract for the period October 1, 1998 to March 30, 1999 was forwarded to the DOE Site Office and Navy Program Office this week for comments. The extension would allow us time to continue processing of SRF cavities for the second FEL module and delay final assembly of the module until we have reached the point of diminished returns on cavity performance. Since the second module is not needed for a period of at least a year, the delayed assembly would yield a higher performance module. This module would continue to serve as a useful testbed of processes for the CEBAF Energy Upgrade and as a hot spare for both the CEBAF accelerator and the FEL linac.

Commissioning Activities

During the week gun reassembly proceeded smoothly and we picked up a full day on the schedule. The gun was successfully high voltage processed to near 500 kV prior to heat treating and cesiating the cathode. However, after the cathode was produced we had difficulty holding off voltage beyond 335 kV and produced no photoemission so it was decided to reactivate the NEG pumps and high voltage process the cathode to 425 kV. Along the way we will gather data from the RGA and also try to determine whether the heat cleaning, or cesiation is the biggest problem in producing voltage standoff at the cathode. As this was written the cathode was holding off nearly the running voltage after a successful cesiation.