Alcator C-MOD Weekly Highlights April 24, 1995 Last week was a scheduled maintenance week on Alcator C-MOD. Activities included a "clean" vent, work on the DC buss, electrical work in the control room, recalibration of various diagnostics, and general maintenance. Plasma operations will resume this week. The DC buss-work was re-configured for normal operation after two weeks of reverse-field (TF and plasma current) experiments. Sections of buss were modified to facilitate future reversals. A re-calibration of the bus diagnostics was also performed. A "clean" vent (helium backfill, no manned entry) was performed early in the week. Borescope inspection of the first wall surfaces was performed. In general, the condition of the first wall was very good. One broken tile was observed on the floor of the vessel, and was identified as a gusset protection tile from the top of the chamber. These tiles are not exposed to significant heat flux during normal operation, and the loss of a single tile at this location poses no difficulties. Some minor damage was noted to one inner-wall limiter tile. Small dust-like metallic particles, presumably molybdenum, were observed on the vessel floor. Also during the vent, a new window was added to a tangential port for rotation measurements, and the lower interferometer window was removed and cleaned. The machine was pumped down again on Tuesday, and a regimen of bakeout and discharge cleaning (ECDC) carried out. The Paragon software on all the engineering PC/PLC stations was upgraded. The PLC software on the CRYO system was improved and streamlined. Testing of new controller boards for the alternator was begun. These boards will permit operation with less droop in the alternator output voltage as the rotation speed drops. Testing of the new circuitry will continue this week. The AC electrical breaker service in the control room has been doubled in capacity. The thermocouple interface boxes on the igloo have been relocated to make room for a new University of Maryland spectrometer, and for the edge Thomson scattering experiment being prepared in collaboration with PPPL and PSI. Three new Alpha workstations (AXP 200-4/233) delivered last week have been installed in the control room and placed in service. Mark May of Johns Hopkins University is at MIT this week working with his UV spectroscopy diagnostic. Experiments employing this instrument to investigate the use of line-ratio measurements of Ni- and Co-like transitions in Pd, Mo, and Nb as an edge electron density diagnostic are scheduled for this week. Roger Richards from ORNL was here last week working on his ion-tail laser scattering experiment. Miklos Porkolab attended the TPX Council Meeting at PPPL. Bruce Lipschultz attended the TPX Physics Advisory Group Meeting at PPPL. He also presented a summary of M.I.T. Activities in support of TPX.