Alcator C-MOD Weekly Highlights June 27, 1995 The scheduled maintenance and upgrade interval is continuing. Most activities were concentrated on machine inspection and preparation for new installations. The igloo cover and top two tiers of igloo blocks were removed. The upper half of the cryostat was then removed, providing access for inspection of the superstructure, cooling lines and buswork, as well as facilitating removal of horizontal port extensions. The E-port ICRF antenna was removed for installation of new antenna protection tiles. The bellows on the current feeds will also be replaced with an improved design. A small leak in the E-port horizontal port secondary seal will also be repaired. A detailed survey of the first wall was carried out, with all loose and damaged tiles mapped out. The gusset protection tiles will be replaced with new, stronger material (already on hand), and the corner tiles have been redesigned for better heat load distribution. Inspection and removal of inner divertor modules for refurbishing continued. Measurements of the outer divertor modules indicated essentially no displacement or distortion since the previous inspection last fall. A full set of current sensing rogowskis to be installed on the outer divertor modules has been completed. These will replace the shunts presently used to measure halo currents flowing through the divertor modules. Marker tiles installed at the beginning of the last campaign were retrieved and sent to Sandia for analysis. These tiles incorporated a thin layer of tungsten covered with an evaporated layer of 100nm of molybdenum, and are used for analysis of erosion and deposition during machine operation. Marker tiles were retrieved from the inner wall and divertor structures.