Alcator C-MOD Weekly Highlights March 20, 1996 Alcator C-Mod is currently up-to-air, but will be pumped down again today so that further ECDC can be done to remove boron hydride deposits on the outer wall and lower divertor cover plates. These deposits formed during boronization at radii beyond which the ECDC resonance was allowed to extend. The ECDC resonance will now be run well out into the horizontal port extensions to break up the hydrides and allow them to be pumped away. In-vessel work has therefore been delayed. However, a great deal of other scheduled work has begun. Transmitter #3 and #4 installation is moving rapidly now that access to the power room is routine. Both crowbar cabinets have been moved into the power room where modifications will continue. The conduit for the #3 transmitter has been installed and HVDC and control cables are being run. Water cooling systems and their associated control and power components are being mounted on their stands. The fixed frequency cavities have been removed from the driver units in preparation for the tunable ones to be supplied as part of our PPPL collaboration. Cooling of our TF magnet during high field runs slowed down our shot cycle considerably during the last run campaign. We are now making modifications to the cryo system to speed up the cooldown time. New valves will be added to the TF magnet manifold so that warmer parts of the magnet can be selectively cooled at higher LN2 pressures. The new system design is complete and major components are on order. Modifications to the LN2 storage tank have begun which will provide higher LN2 flow rates to the pump. A new LN2 pump has been installed, and the old one sent out to be reconditioned. We have also continued work on our diagnostic stand extension. Most components have been fabricated and installation will begin next week. This extension will provide much needed new floorspace in the cell for future systems such as the diagnostic neutral beam (to be installed in collaboration with the University of Texas). Evolution of the finite-element model of the inner and outer divertor continues. This model allows us to determine forces on the divertor plates with various assumptions about halo and eddy current distributions. Input of magnetics data from a C-Mod disruption is being incorporated into the model. This effort is required to ensure reliable operation of our new inner and outer divertor hardware at up to 2 MA of plasma current. Paul Bonoli is at the Sherwood meeting this week. Martin Greenwald, Amanda Hubbard, and Darren Garnier attended the TTF workshop in Philadelphia last week and gave talks. Alberto Loarte is visiting from JET to collaborate on our divertor physics modeling effort. Don McDonald and Bob Phelan visited from Boulder Metric, Inc. to discuss techniques for improved absolute calibration of detectors from mm to visible wavelengths.