Alcator C-Mod Weekly Highlights
				July 7, 1997

Last week was a scheduled maintenance week at Alcator C-Mod. There were no
runs. Next week will also be a scheduled maintenance week. 

The General Electric teams were on-site, working double shifts last week. We
should have access to the location of the alternator ground fault by the end
of this week. At that time, it will be possible to evaluate its condition and
begin any necessary repairs. It seems likely that the present maintenance
interval will be extended, in which case the two run weeks originally planned
for the month of July would be rescheduled.

Maintenance work on the 80 MHz ICRF system was begun.  The four directional
couplers used in matching the antennas have been removed and recalibrated.
Their values where not more than 2% different from the previous calibration
done in 1994, but D-port directional coupler 1 had the coupling factor
switched in the tree.  This error resulted in a 10% underestimate of the
D-port forward power.  A half wavelength stub has been installed on the 80 MHz
dummy load, so transmitters 1 and 2 can be tested into a non-50 ohm load.
This change will also allow the arc detection system to be tested as well.
Several PPPL demodulators not currently in use were modified to provide better
dynamic range and will undergo testing before using them in the RF
instrumentation.  Work has also begun on completing the gas system used to
pressurize the coax lines.  The 40 MHz RFT dummy load was disassembled and the
center conductor sent back to RFT for repairs.

In preparation for installation of the low capacitance transmission line for
the DNB, a consulting engineer began a review of the truss loading in the
power room to determine location for transmission line supports.  Fabrication
of the duct connectors continued.  Other aspects of transmission line design,
fabrication, and installation await the results of the consultation.
Development of the PLC programming for the DNB began.  Design of the voltage
divider assembly for measurement of beamline parameters was completed, and the
unit was submitted for fabrication.  Remaining assembly of the beamline awaits
fabrication of additional support structures which are in progress.

We have installed MDSplus on a VMS cluster at PPPL which will allow them
to evaluate this software for use on NSTX. Users at PPPL can now access
TFTR waveforms via MDSplus.  A TDI function was written which calls the
existing TFTR waveform access routines. A TFTR MDSplus model tree was
built with nodes which refer to TFTR waveforms.  Creating "pulse files"
for any shot will allow access to any TFTR data.  The TRAVERSER utility,
used for examining and editing tree structures, and SCOPE, used for
plotting tree data are also available.  Work is continuing on the
UNIX/WIN32 port of MDSplus.

G. Cima, UT-FRC, and R. Gandy, Auburn, visited to discuss the design of the
ECE antenna for the new heterodyne radiometer that is being installed by
the UT/Auburn/MIT collaboration.

Pablo Acedo and Horacio Lamela from Carlos III University, Madrid, were here
last week working on the new tangential interferometer.  Pablo Acedo will
continue his stay one more week, and return when plasma operations begin.

Two UT-FRC students, Xavier Bonnin and Ashley Shugart, continued their
visits.  Bonnin is working with PFC personnel to develop a B2/Eirene
simulation of the C-Mod divertor.  Shugart is assisting PFC personnel in
the installation of a phase contrast interferometer.