Alcator C-MOD Weekly Highlights December 5, 1995 The Alcator C-MOD operating campaign continued last week, with 4 run days scheduled and completed. The RF antennas were conditioned up to nominal power levels, corresponding to over 3MW of ICRF coupled to the plasma. The goal of reliable 1.5MW power from each antenna was achieved. Both ELMy and ELM-free H-modes were produced with energy confinement times up to 75 msec. During the course of conditioning (which can also be considered to be a fine-step power scan) we have several instances in which the H-mode threshold was barely crossed. These data will add to our L-H threshold database. The deuterium pellet injector was tested during several runs. The injector and pellet tracking diagnostics performed well and the system can now be considered operational for this run period. The new fast conducting limiting valves are working well, with pressure rise in the main vacuum chamber consistent with particle inventory from the pellets alone. Control of the toroidal field by waveform programming through the hybrid computer was successfully implemented. This feature will allow us to decouple machine startup from the flat-top toroidal field value. In addition, having control over the TF waveform, rather than just a level set by PLC, will be convenient for a number of experiments. Preparations for boronization are continuing. The PLC software is being developed and the PC to interface to the boronization control PLC has been installed in the control room. Formal procedures are being finalized. Planning for installation of a diagnostic neutral beam in collaboration with the University of Texas group is proceeding. We are presently investigating use of an on-site 65kV supply to replace the Texas DNB cap bank. Design of a diagnostic stand extension to provide space for DNB and divertor cryopump components has begun. More than 50% of the proto-type cryopump components have been completed. Assembly can begin with delivery of the bellows that make up the LHe containment pots. Dr. H. Sugai from Nagoya University visited C-MOD last week. Dr. Sugai provided a very useful discussion of his experience with use of ECDC for boronization. John Rice and Bob Granetz of the C-MOD group presented papers at the Toki Conference on Fusion Plasma Diagnostics in Toki-City, Japan.