Alcator C-Mod Weekly Highlights
			August 21, 2006

FY2006 weeks of research operations:
   JOULE target: 14 weeks
   Completed: 16.7 weeks

Operations
----------

The manned-access vent continued last week at Alcator C-Mod. In-vessel
activities included post-run diagnostic calibration and alignment checks for
several systems. Removal of outer divertor modules in preparation for
installation of new Tungsten plasma-facing-components has also begun.

Scheduled maintenance continued at the MIT Alternator.

Additional instrumentation required for trouble-shooting the EFC power
supplies has been completed.

Cryopump
--------

The first cool-down tests of the full-scale cryopump prototype were performed
in the cryopump test stand on Thursday. Liquid helium was successfully
transfered into the toroidal loop and maintained there for extended periods of
time. The liquid helium level sensor performed well, indicating a level of up
to half full (the target value) and showing the expected gradual decrease over
time. Helium boil-off rates without gas load were measured to be 3 liters of
liquid He per hour. A set of initial deuterium gas pumping tests were also
performed. The overall system pumping speed, which includes the effect of
baffles that simulate the divertor and tile structure in C- Mod, was measured
to be in the range of 7000 to up to 9700 l/s for D2 gas throughputs of
2.5 to 25 Torr-l/s.  These values are consistent with expectations.

Lower Hybrid System
-------------------

All transmitters were run into dummy loads briefly last week after the
waveguides were disconnected from the launcher and blanked off, in preparation
for further tests.  Testing and conditioning at higher beam voltage is planned
to continue this week.

In-vessel measurements of the launcher position relative to the adjacent fixed
guard limiter confirmed a ~2 mm discrepancy between the position inferred from
the shaft encoder and the actual coupler location. This result implies that
during some of the LH plasma experiments the front of the coupler was actually
up to 1mm forward of the guard tiles; the coupler was still in the shadow of
the main limiter which maps to a location 5mm in front of these tiles.

Design work for the upgraded digital Coupler Protection System is underway.

ICRF System
-----------

Work is proceding on the Fast Ferrite Tuner (FFT) which will provide real-time
tuning of the E-port ICRF antenna system during the next campaign. Testing of
the new power supplies for this system has begun. Development of the control
software for the FFT system was begun, using hardware borrowed from the
development system for the Digital Plasma Control System.

Travel and Visitors
-------------------

 From August 7-10, 2006, John Wright and Paul Bonoli traveled to ORNL
and participated in the summer workshop of the SciDAC Center
for Simulation of Waves in Plasmas.

Valerie Izzo attended the NIMROD summer meeting held in Seattle, WA from
Aug. 14-16. She presented a talk on progress with NIMROD modeling
of disruption mitigation on C-Mod.

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