Alcator C-Mod Weekly Highlights
			December 28, 1998


Engineering:
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Work continued last week on preparing engineering systems for machine
operation.  The CRYO system that controls liquid nitrogen flow to the magnets
has been checked out as far as possible without actually beginning a cooldown.
The HEAT system that maintains the vacuum vessel at room temperature and also
provides thermocouple information from the machine is nearly re-installed with
new connectors and cabling.  This system is needed before we can bake the
vessel and prepare it for plasma operation.  The ECDC horn which used to be at
F-horizontal was removed to provide room for the new DNB diagnostics; it has
been replaced by a new horn and window at H-horizontal.  The new waveguide run
for this system is also nearly complete.  Work also continued on testing and
re-calibrating bus diagnostics.  Known currents and voltages are being applied
to the bus Rogowskis and voltage dividers and test shots taken.  Signals into
the Hybrid computer are also being recorded and checked.

After pumpdown last week, several leaks were found and fixed.  One
known leak still remains to be fixed on one of our lower vertical port
Helicoflex seals.  Once this leak is fixed, a final leak check is done,
and the Heat system is complete, we will be ready to bake the
machine at 150C for approximately three days followed by a campaign of
ECDC to prepare the vessel walls.

Progress continued on DNB diagnostics and DNB installation. Prior to pump-down
on Monday, the in-vessel optics for MSE/BES were aligned and installed and the
location of the image plane measured.  CXRS in-vessel optics adequate for
impurity ion temperature measurement and for toroidal rotation measurements
were installed and aligned, and the location of the viewed volume documented.
Baking of the in-vessel fiber optics was completed, and the fiber optics
routed in the vacuum vessel to the fiber optic faceplate on F-port horizontal
flange.  In the course of test fit-ups, a simple benchtop system was devised
and checked to facilitate reliable alignments to be performed outside of the
vacuum vessel. The CXRS poloidal rotation optics have been tested and aligned
on the bench at UT-FRC.  All flanges on the F-port horizontal flange were
sealed, secured, and readied for pumpdown.  A temporary support was installed
which will secure the gate valve and installed portions of the beamline until
installation of the DNB.  Modification of the diagnostic stand for the
beamline began.  Work continued on the electronics for control of the Mod/Reg
tube, systems to maintain conditioning of the power supply oil, and hardware
modifications to the Mod/Reg cabinet to accommodate the new electronics.

We continue to align, calibrate, and install diagnostics such as ECE,
TTCI, impurity injector, periscopes, and scanning probes.  Preparations
are being made for calibration of our core Thomson scattering system.

RF: 
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The electrical characteristics, S-parameters, of the newly installed J-port
antenna were measured.  These measurements will be used to finalize the
resonant loop design.  A dry nitrogen system, from the C-Mod vaporizor, has
been installed on all ICRF systems (on the matched 9" coax in FMIT#1&2 coax
run and on the unmatched 9" coax run in FMIT#3&4).  We received word that the
first 2274 tube has arced during testing at EIMAC and therefore the delivery
will be delayed at least two weeks (we now expect the tube no earlier than
January 25th.) This tube is intended for use in FMIT#4, which will be used
with the J-port antenna. A spare 2274 tube is also awaiting repair at EIMAC.
The delay will not impact conditioning or operation of the D&E-port antennas,
which are scheduled to come on-line first.

Travel and Visits:
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Dave Johnson from PPPL visited last week for 2 days to work with us on the
edge Thomson scattering system.

On December 16 and 17 Josh Stillerman attended a Department of Energy workshop
on remote collaboration in Germantown Md.