Alcator C-Mod Weekly Highlights
                September 2, 2008


FY2008 weeks of research operations:
   Target: 15 weeks
   Completed:  15.7 weeks


Operations
----------

Refurbishment continued on the vessel heaters.  Improvements to the
vessel insulation that covers the heaters is being discussed.
Relocation of thermocouples used to control the heaters will allow us to
greatly improve the temperature control algorithm.  We continued removal
of feltmetal from the TF arms in preparation for installation of the new
feltmetal, which is now being silver plated.  The TF leg LN2 manifold is
being split into two manifolds with independent valves to allow finer
control of the TF magnet cooling during this inspection period.

Honing of the alternator rotor bore was completed by GE last week and
ultrasonic testing (UT) of the bore has begun.  Both MIT and GE have
completed UT work on the alternator rotor forging bolts.  Though initial
results from the GE test look very promising, we are awaiting a full
report on their results. The MIT tests indicate all twelve bolts are in
good condition.



ICRF Systems
------------

Work continued on the solid state intermediate power amplifier upgrade.
New breaker and contactor systems are being installed.  Progress is
being made on the control interface design.


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

High power tests of the 4-way splitter continued last week.  A full
range of matched and shorted output port configurations were tested at
the 200 kW power level, for 0.5 s.  No faults occurred, even including
cases considered to be worst case conditions.

Work continued on simulations of the lower hybrid coupler looking at the
addition of phase shifters in the waveguides to equalize the poloidal
phase distribution at the plasma, and the mechanical stresses associated
with these changes.  The addition of a tuning element just before the
4-way split is also being considered.

A review of the new launcher design will be held at MIT on Sept 9th.
Steve Knowlton, Auburn, and Douglas Loesser, PPPL, will comprise the
external review panel.


Diagnostics
-----------

Work continued on development of a low noise amplifier for the
polarimeter FIR detector signals.  Signals suitable for driving a
limiter stage and phase detectors have been easily produced while using
less than 1% of available laser power.  Tests of the FIR lasers indicate
they are stable enough for long term operation even without using the
frequency control feedback system.

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