Alcator C-MOD Weekly Highlights
				April 14,1994

Room temperature leak checking was completed by Friday, and a high temperature
bakeout began over the weekend. However, at 100C two leaks developed on the
outer horizontal flanges on ports F and G. The leaks were found to be at the
main C-seals. The bake was terminated and the machine was vented on Monday to
replace the leaking seals. We have experienced an atypically high occurrence
of leaks on these seals this time, so it was decided to replace the C-seals on
F and G with viton. This option had been previously studied, and was
determined to be satisfactory for the outer flange seals, which can be
maintained at temperatures well above 0C. We are investigating whether there
may be a problem with the latest batch of C-seals. The machine is presently
back under vacuum and has again passed leak checking at room temperature.

During the course of the bake, it was found that the rate at which LN2 could
be supplied to the sump was lower than anticipated, and was decreasing. The
problem was identified as being associated with a new phase separator in the
fill line. This line was re-routed and a different phase separator
design introduced to resolve the difficulty. 

The EFC chopper supply has been tested into the dummy coil. The new current
limiting circuit performed correctly. This circuit has been introduced to
prevent the supply from faulting with an IOC condition during large vertical
excursions. These tests were carried out using the new PCS interface software
and the upgraded Hybrid computer hardware. The new integrators in the PID
stage of the hybrid were also exercised and performed nominally. 

The TCI interferometer optics have been installed on on the top of the igloo,
and the beam aligned through the machine. C. H. Ma, from ORNL, is on-site this
week for tests of his Faraday rotation diagnostic, which is installed in the
TCI beamline. These tests are proceeding.

The YAG Thomson scattering beam optics have also been installed on top of the
igloo, and aligned. The beam scanner has been aligned to move the beam across
the plasma in a radial plane.

The unit #2 FMIT ICRF transmitter has been tested to 1MW into the dummy load.
Testing to higher power has been deferred in order to complete work on the
remote control for this unit, in anticipation of power room access being
restricted. The ceramic insulators for the 4 inch coax lines that feed the
dipole antennas have been received; those at D-port have now been installed.
Low power characterization of the D-port antenna is in progress. 

No-power tests of the operating and data acquisition cycle are being carried
out. Indications are that the new computer hardware and software introduced
since the last run should allow us to speed up the shot cycle significantly.
The new SCSI-based serial highway driver (CAMAC) connected to one of our AXP
computers is operational, and significantly outperformed the older q-bus
highway drivers during these tests. 

The Experimental Program Committee has reviewed 17 new Miniproposals for
experimental time during the upcoming campaign. A tentative schedule for
experiments to be carried out during the first two operating weeks has been 
established. Additional Miniproposals are being accepted and will be reviewed
at future meetings of the Committee. Run scheduling for approved MP's  will
continue to be done in two to three week blocks as the campaign proceeds.