Alcator C-Mod Weekly Highlights
			Sept. 12, 2005

FY2005 weeks of research operations
Planned: 17 weeks
Completed: 18.4 weeks


Operations
----------

Since the end of plasma operation on 8/31, Alcator C-Mod has been
warming up to room temperature and preparations have been made for
in-vessel work.  During this up-to-air the major activities include
modifications to the J-Port antenna to test operation without a
Faraday shield, inspection of all antennas, removal of titanium dust
from the vessel, and clean up and calibration of in-vessel diagnostic
systems.

Preventative maintenance programs scheduled for the up-to-air period
have begun on the alternator, backup power diesels, cryo and heating
systems, and machine instrumentation.


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

Last week a faulted rectifier stack for the FMIT#3 transmitter high
voltage power supply was craned out of the supply tank and brought
into the rf lab for repair.  The stack has been checked out and the
bad components identified.  PPPL is providing diodes for use in this
repair, saving procurement time.

Molybdenum stock for the new J-Port antenna septum plates was sent out
to be water cut last week.  They will require in-house machining on
their return.

Low power experiments have been performed to investigate neutral
pressure limits of the E- and J-Port antennas.  The results indicate
that the onset of a multipactor-induced glow discharge occurs at
pressures very similar to the pressure limits found during plasma
operation (0.5 mtorr for J; 1.0 mTorr for E).  These results are
consistent with data from our coaxial multipactor lab experiment
which indicates a new multipactor-induced breakdown regime.


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

Inspection of the #1 stainless steel coupler indicated a lack of Ni
plating in three channels that resulted in badly wetted surfaces and
inadequate braze flow. Coupler #2 has been stripped of its original
plating and re-plated by another vendor.  Extensive testing of the
plating will be completed before another braze cycle is performed.

All twelve klystrons were brought back online successfully last week
as phase and amplitude calibration work continued.


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

Peter Milne from D-TACQ Solutions Ltd visited with Josh Stillerman
last week to discuss new CPCI digitizer boards, upgrade firmware on
our existing boards, and configure a new computer for low latency
control system applications.
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