Alcator C-MOD Weekly Highlights Oct. 10, 1995 Alcator C-MOD is completing the scheduled maintenance interval and preparing for the fall operating campaign. All in-vessel work has been completed and the tokamak is under vacuum again. Checkout of auxiliary systems has begun. Prior to closing the machine, the edge Thomson scattering system internal optics were installed and aligned. The Omegatron edge plasma diagnostic and all bolometer arrays were installed. Final calibrations and alignments were completed for the H-alpha arrays, bolometers, first-wall thermocouples, charge exchange diagnostics, divertor spectroscopy, pellet tracking camera, visible bremsstrahlung array, neutron diagnostics, and TCI interferometer. A final inspection of the vessel was then carried out, and pump-down begun. The initial leak-check cycle is now underway. The TF scanner has been exercised as part of the regular control cycle, and a baseline of turn-to-turn resistances established. The vessel heating system is operational, and is currently maintaining the vessel at 45 C. PLC control for the new EF4 supply is now working. The EF4 supply was pulsed locally without high power. This verified proper operation of the PLC logic, regulator circuits and remote interlocks. The phasing of the gates was controlled by remote current and voltage commands during the pulses. The EF4 breaker control functions were tested for appropriate actions under simulated fault conditions. The I^2t interlock board and shunt were completed and work on the Paragon screen has progressed. The transformer was hi-potted to 24kV. All alternator systems preventative maintenance procedures which were scheduled to be carried out during the three-month maintenance period have been completed. A modification to the control circuits to avoid spurious tripouts on a Volts/Hz limit, which occurred because of field forcing which maintains voltage as the speed drops, was implemented and tested. An alternator test run, including operational checks of all systems, was successfully carried out. Progress continues on the new tangential interferometer diagnostic. All optics except the beamsplitter have arrived. The Bragg cell is now in-house. The optical layout has been completed. A composite optical table is on order. Alan Wootton and Ken Gentle of the University of Texas visited the PFC last week to explore possibilities for collaborations on C-MOD. Several interesting potential topics were identified. Dr. Tohru Mizuuchi is visiting the Plasma Fusion Center from the Plasma Physics Laboratory at Kyoto University for approximately two months. The visit is within the framework of US-Japan Collaboration QL177 . He will be working with the C-MOD edge group principally on edge data analysis (probes) and interpretation. He may also assist in development of the omegatron diagnostic. He has experience with boronization using ECDC and may assist us in that area as well.