Alcator C-Mod Weekly Highlights February 19, 2007 FY2007 weeks of research operations: tentative target: 15 weeks Completed: 0 weeks Operations ---------- After checking set-points, alarms, and other instrumentation last week, we are prepared to operate the alternator at low speed over the next few days. An extensive checkout of the magnet supplies is also underway in preparation for tokamak operation. Work continued on the upgrade to the scanner system for the vessel heater thermocouples. Moisture levels in the C-Mod cryostat are now sufficiently low for liquid nitrogen to be introduced into the sump as required. Cryopump -------- The cyropump installation including all upper chamber protection hardware is complete. Work continued on both the programmable logic controller hardware and software required to operate the cryopump. The liquid nitrogen fill station upgrades in the C-Mod cell required to feed both the cryopump and the diagnostic neutral beam cryopanels have been completed. Lower Hybrid System ------------------- The new lower hybrid water load has been successfully tested with 290 kW, 0.5 s long pulses, and the expected low reflection coefficient was found (-30 db). Spurious faults in the high voltage crowbar system delayed water load testing somewhat. Additional instrumentation is being added to help locate the cause of the faults (this issue is unrelated to the klystrons). Preparations are being made for phase and amplitude calibrations of the lower hybrid system. Work continued on the upgrade to the coupler protection system (CPS), and we are ready to begin procurement of the high speed digitizers with on-board field programmable gate arrays needed for this system. ICRF Systems ------------ With re-installation of the J-Port antenna, all ICRF antennas are now in place. Re-installation of the external matching system for D- and E-Port antennas is also nearly complete. Final preparations are being made to move the fast ferrite tuner (FFT) control racks into the cell. New 96 channel digitizers have been installed and tested in the RF Monitor system. This system is triggered by rf fault conditions and provides both pre- and post-event data at a high data rate. MDSPlus software to support these new high speed, high channel density boards is under development. Long Pulse Diagnostic Neutral Beam ---------------------------------- The DNB is operational with 43 kV, ~4 amps, 100 ms pulses. Beam spectra and component analysis is working automatically, as is analysis of calorimeter thermocouple data. Diagnostics ----------- Seven new magnetic pick-up coil limiters have been installed 10 cm above and below the mid-plane between ports KA, AB, BC, and EF. These coils will provide improved low toroidal mode number resolution for Alfven cascades and any other low n modes picked up at the wall. Diagnostic alignments and calibrations continued last week. The NINJA gas puff system has been brought back on-line and, its proper operation was confirmed. Fabrication of the K-Port bolometer box and limiter is complete and installation has begun. Work continues on the polarimeter shutter, surface science station, probe arrays, upgrades to the plasma video system, and new x-ray systems. Travel and Visits ----------------- Stewart Zweben visited C-Mod last week to continue installation of the GPI imaging diagnostics. He and Jim Terry tested the transmission of the GPI optics which were installed in the vessel the previous week. Stewart also worked on analysis of the GPI diode data from the 2005-2006 run. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly