From:
irby@PSFC.MIT.EDU
Reply-To: IRBY@PSFC.MIT.EDU
Subject: Alcator C-Mod Weekly Highlights
Newsgroups:
sci.physics.plasma
Organization: MIT
Alcator C-Mod Weekly
Highlights
April 5,
2002
Insertion of the outer TF springplates was begun early
this week and will
continue into the weekend. Work on invessel diagnostics and ICRF hardware
is
proceeding. Preparations are being made
to continue the commissioning
of the Lower Hybrid MIE Project high voltage
power supply.
Operations
----------
Assembly
of the machine early in the week concentrated on verifying
proper
alignment of the vertical legs and wedge plates. These alignments
must be very carefully done to allow proper
installation of the cylinder
and taper pins that fix the cylinder to the
wedge plates. Insertion of the
outer
TF springplates is progressing with completion expected over the weekend
or
early next week. Other preparations for
installation of the cylinder
continued.
Instrumentation on the machine has been checked out, upper TF
cooling
tubes installed, and vessel thermal insulation checked and refurbished.
Lower
Hybrid MIE Project
------------------------
Only a few cables
remain to be run to complete wiring of the LH
transmitters. Power-up tests of transmitter #3
continue. The DC power supply,
the
3-phase AC for the supply cabinet, and the filament supplies to all four
tubes
were brought into operation. The
fiber-optic signals to enable and
turn on both water-cooling pumps were
tested, as were the vac-ion pump
supplies, and the power to the input RF
switch. The redesign of the
Transmitter
Protection System (TPS) optical interface board #2 to include the
DFOL
circuit is complete. The printed
circuit board layout is complete, and
the board will be sent out for
fabrication next week. The
nitrogen
distribution manifold to pressurize the waveguide is nearing
completion.
We expect the HVPS vendor's engineering team to return
next week to continue
commissioning and acceptance tests of the
supply. A water cooling heat
exchanger
on loan to Alcator from our Fusion Engineering and Technology
Division is
being installed on the HVPS dummy load so that 10 second
long pulses can
be run at rapid repetition rates.
ICRF Systems
------------
The
J-Port antenna straps were sent out to be plated and are now back
in
house. One D-Port strap was sent out to be brush plated and is also back
in
house and being prepared for baking.
The D and E-Port Faraday screens are
at the brush plating vendor
for detail masking and plating and are expected
back in house by early
next week. The BN tiles are being
manufactured and
will require a high temperature bake (~1250 C) to reduce
the hydrogen
content. The E-Port vacuum feedthroughs are being cleaned in
preparation
for installation. The
J-Port flange has also been prepared for installation.
The new
support for the D and E-port transmission line has been
partially
constructed. Once finished, a more
accurate estimate of the
new transmission line components can be
made.
RFX DNB
-------
The final design of the gas control and water
cooling systems was completed
this week.
Upgrades to the beam PLC and Paragon software have been made to
aid
regeneration of the cryo panels and indicate water flow status. The
design of a system to automatically
fill the cryopanel reservoir from our
main LN2 tank is being
developed.
Diagnostics
-----------
The test
assembly of the edge CXRS telescope and shutter went well this week.
Minor
changes may be required before installation.
The bake and
assembly of the new inner wall scanning probe were
also completed this week,
and the probe is ready for installation.
The
MSE invessel optics is nearing completion.
All mirrors and lenses
have been installed into their holders. The new holder design is expected
to
handle disruptions loads very effectively. The assembled lens sets
have
also been installed into the invessel canister, and the mirrors are
being
aligned. A throughput test and a good
deal of spot welding remains to
be done on the outside of the can. The invessel can should be ready for
installation
at the end of next week. A new vacuum
interface window using
low Verdet glass is being designed; the glass for
the window should arrive in
about 2 weeks. All of the approximately 175 of
the machine side quartz fibers
have been polished, and the ends mating to
the PMTs tested successfully. The
custom
ferrules have arrived from PPPL and a successful fitup was performed.
All
MSE channels will be upgraded to 16 fibers looking at the center of the
beam. The new image dissector, which will help
prevent damage to the fibers,
is being made at PPPL and should be
completed Monday. A retention mechanism
is still being designed. In house fabrication of the invessel
backlighting
and absolute calibration tool is nearly done. A new technique being
developed for
doing remote backlighting for MSE/BES/CXRS looks promising,
and will be
taking advantage of the wireless ethernet system which was recently
installed
in the cell.
The new Active MHD antennas at GH port are now
completed. The in-vessel
fitup has
been performed. The tiles will be
removed and vacuum baked with the
ICRF boron nitride tiles next week. The antenna hi-pot was successful.
A
picture of the antenna without the tiles, showing the 5 turn coil,
can be
found at
http://www.psfc.mit.edu/cmod/operations/EngImages/Inspection_2001-2002/Disassembly_Assembly/Machine_assembly_A/DCP_0370.JPG
A
picture of the completed antennas with the BN tiles during the invessel
fitup
can be seen at
http://www.psfc.mit.edu/cmod/operations/EngImages/Inspection_2001-2002/Disassembly_Assembly/Machine_assembly_A/DCP_0389.JPG
Travel
and Visits
-----------------
Approximately twenty Senior
Congressional Staffers were on the MIT campus
attending a three day
Seminar on Energy Policy, organized by the Sloan
School. On Thursday evening they were invited to a
reception and tour of
the PSFC.
Miklos Porkolab gave a talk to the staffers on fusion, and
tours of
Alcator C-Mod, LDX, VTF, PTF, and the Plasmatron were given.
Martin
Greenwald, Ian Hutchinson, Amanda Hubbard, and Valerie Censabella,
attended
the TTF meeting in Annapolis this week.
Amanda gave an invited
talk on "LH and Pedestal Transport
Physics Issues". Catherine
gave
a talk on "Recent Results of Internal Transport Barrier Studies
on Alcator
C-Mod", and Martin presented a talk on C-Mod transport
plans.
Martha Redi, David Mikkelsen and Stew Zweben, all of PPPL,
also attended the
TTF meeting in Annapolis and presented their work on
C-Mod related transport
modeling and edge turbulence studies.
On
Tuesday, April 2nd, Amanda Hubbard visited the University of Maryland and
gave
a seminar on "Edge Transport Barrier Formation and Scalings on
Alcator
C-Mod".
Gerd Schilling, PPPL,
was at MIT 4/1-4/4 for discussions and updates on ICRF
hardware,
diagnostics and the machine reassembly schedule.