Alcator C-Mod Weekly Highlights
			December 7, 1998



Reassembly of Alcator C-Mod continued last week.  All cooling lines are
installed and have passed all required inspections.  Nitrogen gas has
been run through the coils to verify that all connections have been properly
made, and that the proportional valves and cooling manifolds are
operational.  The magnets were successfully hi-potted and rung through the
bus tunnel indicating that both the copper bus and the magnets are ready
for operation.  The curved bus around the cylinder also went through several
inspections focused on bus connections and insulation.  Resistance checks of
the OH feltmetal indicate all three joints are well within spec (< 1 uOhm).
With these tests completed, the remainder of the cryostat was installed,
bolted together, and fiberglassed.  The boots that seal the horizontal and
vertical ports to the cryostat were put in place this week, and final sealing
to the cryostat is underway.  Insulation to protect the horizontal
inner seals from liquid nitrogen was also installed. Installation of the
igloo around the cryostat will begin early this week as the boot seals
are completed.

A great deal of work has been done by the Vacuum group over the last
week.  All upper vertical port crosses and tees have been installed.
With completion of work on the horizontal port extensions, the lower
cryostat was raised.  This operation allowed work to begin on the lower
vertical ports.  Seven out of nine lower crosses and tees have been installed
allowing the installation of diagnostic cabling and periscopes to
begin.  The lower TCI gatevalve has also been installed.  Now that the cryostat
upper cover is in place, we can also install the upper TCI and PCI
gatevalves.  

Invessel work included the installation of a new inner wall strain gauge
which is located between the two rangefinder retro-reflectors.  Both
relative movement and the resulting strain will therefore be measured at this
location.  This information will be very useful as we complete the design of
the new inner divertor and plan for higher current operation.  The AB split
limiter was also installed last week and cabling for the new MHD coils located
on the limiter was begun.  Studs were also installed at the limiter midplane
for the new TTCI retro-reflector mount.  A test fitup of the CXRS optics was
completed and minor alignment modifications made.  Installation of the MSE
optics continued.  The installation of the J-port antenna has been delayed
because of difficulties encountered in re-plating the current straps, and some
rework required to the Faraday screens.  A very thick coating of nickel was
found under the copper plating which took several days to strip.  However,
the straps are now back in house, visually appear to be in very good condition,
and have survived a very severe tape pull test and 400C bake cycle without
blistering.  They will be ready for installation early this week.
The Faraday screens are back at PPPL being reformed to the proper shape after
they suffered some distortion during their final bake process.  We expect
to have the screens back in house ready for installation late this week.
Remaining activities invessel include installation and calibration of
several diagnostics, re-attachment of the diborane gas feed manifold, and
installation of the glow discharge cabling.  Installation of the divertor
bypass flaps is scheduled for midweek.

Preparations by the RF group for the upcoming campaign are continuing.
Antennas D and E and their feedthroughs are installed in the machine.
Transmitters FMIT#1 and #2 which power the D and E antennas, respectively,
have been tested (1.8 MW each into the dummy load).  The associated resonant
loops have been assembled and await installation.  D and E antenna
instrumentation installation is approaching completion.  System testing
remains to be done.  FMIT#4, which together with FMIT#3 will power the new
J-port antenna, is still awaiting arrival of the repaired FPA tube.  We
expect the tube to be in house within the next two to three weeks.  The
resonant loop design is undergoing a final design review.  All components
of the J-port antenna have now passed the tape pull test and a 400C
bakeout without blistering.  The J-port antenna feedthroughs have been
leak checked, and the external support for them has been fabricated.
A final alignment of the antenna at PPPL is now underway in preparation
for installation.

The layout for the board controlling the DNB Mod/Reg protection
crowbar was completed, checked, and after a few modifications will be sent
out for fabrication next week.  Some parts on the grid drive board for the
Mod/Reg were exchanged for modern components so that the layout of the PC
board can begin next week.  Work continued on the tube regulator and
monitor boards for the Mod/Reg.  Conditioning of the oil in the DNB
accelerator power supply is complete.


Travel and Visits:

Many people from PPPL visited last week as part of the PPPL/MIT collaboration.
David Mikkelsen, who visited all last week is now a regular part of
the PPPL collaboration.  He will be working on transport modelling.
Gary Taylor visited to work on the GPC2 instrument.  Norton Bretz and Dave
Cylinder were here several days working to install the MSE diagnostic.
Gerd Schilling returned to help both with the new J-port antenna and
re-installation of the D and E port RF systems.  Les Gereg and Joe Frangipani
were also here working on the J-port antenna installation.  Many of these
people will also be here this week finishing up installation of their
invessel components.

Amanda Hubbard visited the Centre Canadien de Fusion Magnetique and
INRS-Energie, in Varennes, Quebec, serving as external examiner for a Ph.D.
thesis.

Miklos Porkolab visited General Atomics on Monday, Nov. 30th, and gave a 
presentation on the Lower hybrid Current Profile Control Experimental 
Proposal for C-Mod. He also participated in discussions clarifying 
AT physics issues and requirements on profile control in ongoing
tokamak experiments, including C-Mod, DIII-D and tokamaks abroad.