Alcator C-Mod Weekly Highlights February 26, 2007 FY2007 weeks of research operations: tentative target: 15 weeks Completed: 0 weeks Operations ---------- All in-vessel work for this up-to-air period was completed by Saturday afternoon, 2/24/07. Alcator C-Mod is currently under vacuum and preparations are being made to bake the vessel. The liquid nitrogen cooling system is operational as is the heater system with its upgraded thermocouple scanner. During the up-to-air major in-vessel objectives successfully completed included installation of the upper chamber cryopump and the complete toroidal belt of tungsten lamella tiles in the outer divertor. The cryopump as installed can be seen in the upper right of the picture found at http://www.psfc.mit.edu/cmod/operations/EngImages/INVESSEL/2007/cryopump_installed/DSCN2366.JPG and a picture of the upper chamber hardware that protects the pump can been seen at http://www.psfc.mit.edu/cmod/operations/EngImages/INVESSEL/2007/20070223_close_up_survey/DSCN2701.JPG The radial slots in the protection hardware allow neutrals to efficiently enter the pumping chamber. The row of ITER-relevant tungsten tiles can be seen at http://www.psfc.mit.edu/cmod/operations/EngImages/INVESSEL/2007/20070223_close_up_survey/DSCN2629.JPG The tungsten tiles are on the 4th row from the top on the right of the picture. Each tile is made of eight 4 mm thick tungsten plates. Work continued preparing the magnet power supplies for operation. Some of the tasks that were completed included an inspection of the transformers and bus work, and maintenance and cleaning of the EFC chopper power supply. The commutation switch capacitor banks were also inspected. The MIT alternator was brought up to full speed last Friday, and following calibration of some of the vibration monitors should be ready for operation. Up-to-Air Period Task List -------------------------- During the up-to-air a partial list of the tasks completed include: install cryopump, install tungsten lamella tiles, rotate the long pulse diagnostic neutral beam, inspect and hi-pot alternator, refurbish antennas to improve high voltage standoff capability, service/upgrade ln2 feedlines, service ln2 vent duct, service power systems, improve sparker system, service/repair plasma facing components as required, replace heat thermocouple scanner, replace high voltage reed relays in toroidal field scanner, data system upgrades, network upgrades, PC to PLC interface upgrades,install new imaging x-ray system for rotation measurements, Neon SOft X-Ray (NeSOX) moved to k-hor 10" flange, install Surface Science Station (microbalances), bolometer upgrades, mods to b-hor for X-Ray upgrade/new detector, MSE cals/checks/mods, flapper removal/cover plate installation, mods to reduce outer divertor radiation, install outer divertor marker tiles, install outer divertor boron tiles, install shutter for polarimeter retros, install seven limiter magnetic coils, mods to tiles at f-port (DNB location) to protect magnetics from beam, mods to CXRS systems, new upper divertor probe array, new cryopump Penning gauges, refurbish Penning gauge cables, install two new inner-wall scanning probes, install new F-top MKS gauge, refurbish outer divertor probe array, install ten new halo Rogowskis in upper divertor, Mo source diag coverage mods, refurbish fast camera telescopes, replace inner wall telescope fiber bundle, install new Gas Puff Imaging telescope on A-B shelf, continue Thomson Scattering upgrades, and improve video camera reliability. In addition, we continued development of new lower hybrid couplers and the new lower hybrid E-plane launcher, increased lower hybrid source power to 3 MW, improved performance of lower hybrid circulators, continued development of the coupler protection system upgrade, and developed a new water load design with 300 kW, 0.5 s capability. Improvements to the ICRF crowbar system, data system, and control system have also been implemented, and a new prototype fast ferrite tuning system for the E-Port ICRF antenna has been developed. Cryopump -------- Work continues on the cryogenic control system for the pump. Fabrication of liquid helium and liquid nitrogen transfer lines continues. Preparation for the 1st cool-down test also continues. Lower Hybrid System ------------------- Following the successful high power test of the new water load reported last week, we have continued fabrication of the remaining eleven loads. Work continued on phase and amplitude calibrations needed for the next run period and development of the CPS (coupler protection system) upgrade. ICRF Systems ------------ The FFT (fast ferrite tuner) control racks have been installed in the cell and are being brought into operation. Work on crowbar cabinets #3 and #4 has been completed. Upgrades to the ICRF data acquisition system continued. Work on the low power driver amplifiers for FMIT transmitters #2 and #3 has been completed. Diagnostics ----------- A new idea for in-situ, between-shot diagnosis of surfaces in a tokamak has been proposed by Dennis Whyte. The technique uses a fixed-energy RFQ (radio frequency quadrapole) accelerator which produces 1 MeV deuteron beam at approximately 1 mA. This ion beam can be steered to different poloidal surfaces by applying a variable-strength toroidal field between 0.1 and 0.5 T. Measurements of gamma-rays and neutrons resulting from the deuteron-surface interaction could provide quantitative measurements of the surface properties, possibly between C-Mod discharges. Travel and Visits ----------------- Perry Phillips, UTexas, was here last week and installed the FRC-ECE waveguides at F-Port and began bringing the system back on-line. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly