Alcator C-Mod Weekly Highlights April 23, 2007 FY2007 weeks of research operations: tentative target: 15 weeks Completed: 1.95 weeks Operations ---------- Last week was a maintenance week at Alcator C-Mod. No runs were scheduled. Plasma operation is planned to resume this week. Cryopump System --------------- Liquid helium and nitrogen transfer lines are now installed in the cell for the upper chamber cryopump. Installation of the support platform for the liquid helium dewar on the igloo was also completed last week. Work continues on the installation of control valves and the control system hardware and software. Long Pulse Diagnostic Neutral Beam ---------------------------------- During the maintenance week, operation of the beam was changed to use the mass flow controllers (MFCs) for fueling the arc plasma source. The mass flow controller waveform shape and timing were modified to provide the same flow rate as the solenoid gas valves. Beam operation using mass flow controllers should provide an improved ability to control the long pulse beam current. ICRF Systems ------------ We continued preparing E-Port antenna for operation last week. Vacuum conditioning of the antenna was begun and all rf systems are now operational. We will begin plasma conditioning of the E-Port antenna this week. We have placed the Fast-Ferrite-Tuners (FFTs) in the cell, connected the power supplies, and verified that the control system is operational. We will use the reflection information obtained from the coupling network without the FFTs to verify the final FFT placement in the network. Lower Hybrid System ------------------- The external waveguide in the vicinity of the teflon-fiberglass gas baffle which required replacement following operations April 9 was inspected and cleaned. Signs of arcing were noted near the RF gasket between the forward and rear waveguides. The system is being reassembled following the cleanup, and conditioning will be carried out this week. We are investigating incorporating optical arc detectors just before the gas baffles to provide added arc protection. Diagnostics ----------- High-frequency filtering is being prepared to eliminate the pick-up from the lower hybrid system observed previously on the FRCECE electron cyclotron emission diagnostic. Maintenance is being performed on the GPC-1 (electron cyclotron emission) detector dewar. Maintenance is also being performed on the Surface Science Station diagnostic platform. Travel and Visitors ------------------- A number of C-Mod physicists and students participated in the 12th US-EU Transport Taskforce Workshop April 17-20 in San Diego, including Amanda Hubbard, Martin Greenwald, Catherine Fiore, John Rice, Alex Ince-Cushman, Joe Snipes, Miklos Porkolab, Liang Lin, and Eric Edlund. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly