Alcator C-Mod Weekly Highlights Jan 13, 2003 The Alcator C-Mod maintenance period continued last week. Work on machine instrumentation, ICRF systems, Lower Hybrid MIE Project, and diagnostics progressed. Operations ---------- We continued to work on upgrades to the TF voltage tap, thermocouple, and heater leads. We are approximately 70% done with this project. A conceptual design for a set of field correction coils has been developed. It is believed that non-axisymmetric error fields may have affected plasma performance during high current operation in the last campaign. A set of coils to be mounted on the igloo structure is proposed to address this issue. ICRF Systems ------------ The placement of the current probes on the D and E Port antennas is being optimized using our rf simulation software. These probes are used to sense faults during operation. A problem with the motorized 13.8 kV switch in the high yard has been identified and repairs are progressing. Lower Hybrid MIE Project ------------------------ Work continued on the new SFOL design. The Low Power Microwave rack SFOL receiver chassis assembly, including the wiring, is complete. The Low Power Microwave rack SFOL transmitter chassis assembly is near completion and the parts arrived to finish the I-Q detector wiring inside the chassis. Five DFOLs for LH system controls have been successfully tested. We continue to specify and procure cabling for the low power microwave rack and interconnections to the launcher. A temporary pump has been installed in the Lower Hybrid water cooling system while warranty work is being performed on the primary pumps. This pump will allow full power tests of the klystrons to be made with the HVPS. MSE Diagnostic -------------- Work continues at PPPL and MIT on developing two approaches for disruption-resilient mirrors for the C-Mod Motional Start Effect (MSE) diagnostic. An approach based on existing spare glass (Vycor) mirrors will use a stainless-steel rib structure that supports the mirror along its entire periphery, and 0.040" Teflon cushioning between all glass and metal surfaces. The design of this approach is complete and fabrication of test components has started. An alternate design is based on a metallic substrate, Inconel 625, coated with silver and overcoated with a dielectric for protection against oxidation. A mechanical design has been completed that reduces disruption forces by removing most of the Inconel substrate from the rear of the mirror. At the present time both designs are being carried along in parallel. Travel and Visits ----------------- Monty Grimes was at AFT in Germany last week reviewing progress on the Lower Hybrid MIE Project circulators.