Alcator C-MOD Weekly Highlights August 4, 1994 The maintenance/repair period is continuing. Work on the new design for the coax buss is proceeding. Prototype components incorporating the new design, which features a more compliant head piece for the inner coax, have been fabricated and will be tested. Additional calculations to verify the design are in progress. While the bus work proceeds, additional maintenance activities are also being carried out. The vessel heaters, which are normally inaccessible, are undergoing a thorough inspection. In-vessel work this week has included removal of a set of tile modules on the inner wall, in preparation for installation of new halo current diagnostics. In addition, we will replace a few of the tiles with specially prepared "tracer" tiles, containing a thin coating of tungsten under an overcoating of molybdenum. This work, being carried out in collaboration with Sandia, will investigate the erosion and re-deposition of molybdenum during high-power operation. A shot from the June, 1994, run period has been selected for additional analysis using the DEGAS code; this work is being carried out by Daren Stotler of PPPL. The particular shot,940623028, was part of a divertor studies run, and includes density and temperature profiles at the target plate and fast-scanning probe profiles in the main chamber, as well as a complete set of H-alpha data. This shot was a low density discharge on which divertor detachment did not occur. C.H. Ma of ORNL is working at MIT this week, preparing his Faraday rotation diagnostic. This diagnostic works in conjunction with our existing Two-Color Interferometer (TCI), and will be used to measure the current density profile. All of the main components of the rotation experiment are now installed on the laser table, and rotations of the order of 2 degrees have been successfully detected using a polarization rotator installed on the table. Professor Ian Hutchinson has returned from his sabbatical at JET. Martin Greenwald is participating in the ESNET Steering Committee Meeting in New Mexico.