Newsgroups: sci.physics.plasma
From IRBY@CMOD2.PFC.MIT.EDU Tue May 21 10:44:35 1996
From: IRBY@CMOD2.PFC.MIT.EDU
Organization: MIT
Subject: Alcator C-MOD Weekly Highlights

Alcator C-MOD Weekly Highlights
May 21, 1996

Our maintenance period continues. Work concentrated
mainly on the divertor last week, with progress being made
on other systems including RF, the divertor cryopump, and TF cooling.
Welding is now more than 20% complete on the divertor support
plate inserts. Machining of the plates is also well underway. Both of
these operations should now go quickly since all the procedures have
been gone over and double checked. One set of
divertor plates is ready to be drilled, after which a test
fitup will be made invessel. UT testing of the outer divertor
tiles has been completed with very few indications found. No tiles
will have to be replaced. However, some melting and delamination on the
edge tiles on closed divertor modules will warrant some contouring to
spread the heat load. This process is quite straightforward and has in
fact been done invessel on a previous occasion (to other tiles).
Wiring of the interface cables to the PLC for transmitters #3
and #4 continues, as does work on the new crowbar cabinets.
Transmitter #2 has been hooked up to a dummy load, and our spare
final amplifier tube has been installed. This tube showed signs of
oscillation during some modes of operation, and this problem will now
be documented, and we hope solved. 160' of the 9" coax recently loaned to us
by PPPL has been moved into position in the power room and will soon be
installed on the support rollers. This coax will provide the two new
transmission line runs needed for transmitters #3 and #4.
We have continued to make improvements to the power system control
boards and protection circuits. The EF4 over voltage detection circuit
has been redesigned and tested. Improvements made as test changes to the
power supply master control boards have been made permanent.
A problem with the EF1 conduction fault board has been identified
and fixed. The EF4 PLC program has been modified to include a latch for all
type 3 faults. All power supply monitor circuits are now being checked and
calibrated for the next run period. A new coaxial shunt has been designed,
built, and installed for use on EF3. The old EF3 shunt had low noise
immunity.
The new manifold for the TF LN2 cooling system has been pressure
tested for leaks, and the valves have been operated and checked for flow
and leak through. PLC control wiring is now being installed.
The divertor cryopump tests indicate deuterium pumping speeds at the
design level of approximately 1800 l/s. Tests which simulated an
unplanned up-to-air indicated that the helium could be safely vented from
the pump very quickly. Initial testing of the pump is complete, and
we are preparing for an invessel fitup.
Rejean Boivin, Tom Fredian, Josh Stillerman, Earl Marmar, and
A.J. Allen attended the High Temperature Plasma Diagnostics Meeting in
Monterey, CA. last week. Miklos Porkolab attended the Fusion Forum in
Washington D.C.

Papers/Posters presented at the High Temperature Plasma Diagnostics
Meeting by Alcator staff and our collaborators included:

Diagnostic Neutral Beam Spectroscopy Requirements for ITER and
Alcator C-Mod, E.S. Marmar (Invited)

Neutral Beam Diagnostics for C-Mod, W.L. Rowan, R.D. Bengtson,
R.V. Bravenec, H. He, J. Jagger, D.M. Patterson, D.W. Ross, P.M.
Valanju, and A.J. Wootton, U of Texas; E.S. Marmar, J.H. Irby,
J.A. Snipes, and J.L. Terry, MIT.

Alcator C-Mod Data Acquisition System, T.W. Fredian, J.A. Stillerman,
and M. Greenwald, MIT.

MDSplus Data Acquisition System, J.A. Stillerman, and T.W. Fredian,
MIT; K.A. Klare, LANL; and G. Manduchi, CNR Padua, Italy.

The High-Resolution Video Capture System on the Alcator C-Mod
Tokamak, A.J. Allen, J.L. Terry, D. Garnier, J.A. Stillerman,
MIT; G.A. Wurden, LANL.

Time-of-Flight Neutral Particl Analyzer for Alcator C-Mod, R.L. Boivin,
and M. Koltonyuk, MIT; C.P. Munson, LANL; and R.M. Mayo, North Carolina
State University.

A Compact Thomson Scattering System, D. Dimock, Princeton Scientific
Instruments; B. Grek, and D. Johnson, PPPL,; B. Labombard, B. Lipschultz,
and G. McCracken, MIT.

The Design of a Second Harmonic Tangential Array Interferometer for
C-Mod, N. Bretz and F Jobes, PPPL; and J. Irby, MIT.

Diagnostics for Local Spectroscopic Measurements in the Divertor
Region of the Alcator C-Mod and DIII-D Tokamaks, M.J. May, S.P. Regan,
V.A. Soukhanovskii, and H.W. Moos, The Johns Hopkins University; J.A.
Goetz, B. Lipschultz, J.L. Terry, MIT; P. West, S. Allen, and N. Brooks,
General Atomics; and M Finkenthal, Hebrew University.