Alcator C-MOD Weekly Highlights May 28, 1996 Our maintenance period continues. Work proceeds on the divertor, the divertor cryopump, RF systems, TF cooling, and diagnostic upgrades. Welding of the divertor support plates is more than 60% complete. All machining operations are complete on 20% of the plates. Outer divertor modules can be re-installed invessel beginning late this week or early next week. The invessel fitup of the divertor cryopump is going well. A minor change to the mounting hardware will be needed to leave more space for a flux loop that runs under the divertor module. The pump vacuum feedthrough mated properly with its flange. Measurements have been made that were needed to complete fabrication of the 300K shield. A test fitup of the GH outer divertor module, which covers the cryopump, will be done as soon as the module is ready for installation. Following the fitup, the pump will be returned to the vacuum test stand where PLC program development can continue, and more pumping speed tests can be made. The closed loop de-ionized water cooling system for the new transmitters is nearly finished. The PLC interface control and indicator wiring is complete. Work has begun on modifications to the new transmitter driver cabinets. Support hardware for the new 9" coax runs is being installed. PLC control cabling to the new TF control valves is complete. PLC programming and debugging can now proceed. All alternator instrumentation has been re-installed and checked, and the alternator is ready for operation. It will be brought up to speed over the next two weeks. Work continued on several other engineering and diagnostic systems. The ceramic tubes that will house the retro-reflectors for the new tangential interferometer were sent out to the vendor where the retro-reflectors will be installed. Stainless steel standoffs for the new glow discharge system are now fabricated and will be sent out for an electrically insulating spray coating. The electrical feedthroughs for the glow discharge system are now being installed on D-top flange. A final design review of the C-port horizontal flange modifications was held and changes to the flange can now begin. A-top flange is being modified for installation of a new RF probe. Brian LaBombard, Garry McCracken, and Bruce Lipschultz were at the PSI meeting in France last week. Yuichi Takase was in Garching at both an ITER design review meeting and the European Coordinating Committee Meeting on Fast Wave Heating and Current Drive. Contributions to the PSI meeting included: Invited paper -- Experimental Investigation of Transport Phenomena in the Scrape-off Layer and Divertor, B. LaBombard, J. Goetz, I. Hutchinson, D. Jablonski, J. Kesner, C. Kurz, B. Lipschultz, G.M. McCracken, A. Niemczewski, J.L. Terry. Contributed oral -- Modification of the Divertor Detachment Onset Density B. Lipschultz, B. LaBombard, G.M. McCracken, J. Goetz, H. Ohkawa, Y. Takase and J.L. Terry. Contributed posters -- A Comparison of Impurity Screening Between Limiter and Divertor Plasmas in the Alcator C-Mod Tokamak, R.S. Granetz, G.M. McCracken, F. Bombarda, J.A. Goetz, D. Jablonski, B. LaBombard, B. Lipschultz, H. Ohkawa, J. Rice, J.L. Terry, Y. Wang. Screening of Recycling and Non-Recycling Impurities in the Alcator C-Mod Tokamak, G.M. McCracken, R.S. Granetz, B. Lipschultz, B. LaBombard, F. Bombarda, J.A. Goetz, D. Jablonski, S. Lisgo, D. Jablonski, H. Ohkawa, J. Rice, P.C. Stangeby, J.L. Terry, Y. Wang. Local Impurity Puffing as a Scrape-off Layer Diagnostic on the Alcator C-Mod Tokamak, D. Jablonski, B. LaBombard, G.M. McCracken, S. Lisgo, B. Lipschultz, I.H. Hutchinson, J.L. Terry, and P.C. Stangeby.