Alcator C-Mod Weekly Highlights November 30, 2001 Work continued on the machine inspection this week. The inner divertor installation proceeded, and we continued work on the Lower Hybrid and ICRF systems. Preparations for the new DNB installation also showed progress. Inspection ---------- We have concluded measurements of the OH coaxes and decided on several modifications to be implemented before reassembly begins. The replacement of six feltmetal pads (out of 1920) on the TF arms has begun using our inductive heating technique. These pads had a "frosting" of the silver plating that we have associated with low levels of the graphite coating we apply as a lubricant on the sliding joint. Our procedures for applying the coating will be modified before machine reassembly begins. Lower Hybrid MIE Project ------------------------ We continued testing transmitter equipment racks and carts this week. A very important protection circuit for the klystrons, which monitors the tube body current, has been debugged and is working properly. Wiring of the flowmeter, pressure, and temperature measurement transducers for the water cooling system has begun. We are nearly ready to release the waveguide flange gasket drawing for quotes. The dummy load for the HVPS is complete and ready for installation. ICRF Systems ------------ On Wednesday a meeting was held to discuss changes to the rf antennas to be implemented before the next run campaign. Modifications to the D and E-port antenna tiles were proposed to shield the fasteners from the plasma (locations where arc damage was seen earlier). The D and E-port Faraday screens, antenna straps, backplate and feedthroughs will be refurbished before the next campaign. New J-port boron nitride end and front tile designs were also proposed to shield the fasteners from the plasma. A modification to the antenna strap at the grounding bridge was presented. It was decided that additional electrostatic calculations should be made around this region to better determine the required strap shape changes. DNB and Related Diagnostics --------------------------- The DNB flange at F-Port is being redesigned for the next run campaign. Work on a 3D model of the flange proceeded this week. The model will be used to check interferences and generate the drawings needed to fabricate the new flange. The new port will have two tangential ports allowing continuation of the visible bremsstralung measurements together with new plasma rotation measurements. Removal of old DNB components from the cell is complete. Preparations for the new beam are proceeding. Inner Divertor -------------- Installation of the new inner wall/divertor, including the Rogowski halo and eddy current monitors and the thermocouples, began this week. About 1/3 of the inconel plates and associated instrumentation have been installed so far. Integration of the new components with pre-existing in-vessel hardware (retro-reflectors, gas-puffing tubes, magnetics) has not presented any major problems thanks to detailed planning and design. Some pictures of the installation can be found at http://www.psfc.mit.edu/cmod/operations/EngImages/CmodImages.asp?ref=/Inspection_ 2001-2002/Disassembly_Assembly/part6/ A view showing approximately 33% of the divertor installed can be seen at http://www.psfc.mit.edu/cmod/operations/EngImages/Inspection_2001-2002/Disassembl y_Assembly/part6/P0002412.JPG This picture also shows the beginnings of the molybdenum tile installation. Travel and Visits ----------------- Miklos Porkolab attended the Snowmass planning meeting at Livermore on Nov. 27,28, and presented plans for the RF subgroup activities, together with Don Batchelor of ORNL. Miklos and Don are the Wave-Particle Interaction Subgroup conveners for Snowmass. Last week, Earl Marmar was in Livermore on Thursday and Friday, for a meeting of the Next Step Options Program Advisory Committee, which advises the Director of the VLT on efforts to design next-step magnetic-confinement fusion facilities for the U.S. program.