Newsgroups: sci.physics.plasma
From WOLFE@CMOD2.PFC.MIT.EDU Tue Apr 25 07:50:45 1995
From: WOLFE@CMOD2.PFC.MIT.EDU
Organization: MIT
Subject: Alcator C-MOD Weekly Highlights

Alcator C-MOD Weekly Highlights
April 24, 1995

Last week was a scheduled maintenance week on Alcator C-MOD. Activities
included a "clean" vent, work on the DC buss, electrical work in the control
room, recalibration of various diagnostics, and general maintenance. Plasma
operations will resume this week.

The DC buss-work was re-configured for normal operation after two weeks of
reverse-field (TF and plasma current) experiments. Sections of buss were
modified to facilitate future reversals. A re-calibration of the bus
diagnostics was also performed.

A "clean" vent (helium backfill, no manned entry) was performed early in the
week. Borescope inspection of the first wall surfaces was performed. In
general, the condition of the first wall was very good. One broken tile was
observed on the floor of the vessel, and was identified as a gusset protection
tile from the top of the chamber. These tiles are not exposed to significant
heat flux during normal operation, and the loss of a single tile at this
location poses no difficulties. Some minor damage was noted to one inner-wall
limiter tile. Small dust-like metallic particles, presumably molybdenum, were
observed on the vessel floor. Also during the vent, a new window was added to
a tangential port for rotation measurements, and the lower interferometer
window was removed and cleaned. The machine was pumped down again on Tuesday,
and a regimen of bakeout and discharge cleaning (ECDC) carried out.

The Paragon software on all the engineering PC/PLC stations was upgraded. The
PLC software on the CRYO system was improved and streamlined.

Testing of new controller boards for the alternator was begun. These boards
will permit operation with less droop in the alternator output voltage as the
rotation speed drops. Testing of the new circuitry will continue this week.

The AC electrical breaker service in the control room has been doubled in
capacity.

The thermocouple interface boxes on the igloo have been relocated to make room
for a new University of Maryland spectrometer, and for the edge Thomson
scattering experiment being prepared in collaboration with PPPL and PSI.

Three new Alpha workstations (AXP 200-4/233) delivered last week have been
installed in the control room and placed in service.

Mark May of Johns Hopkins University is at MIT this week working with his UV
spectroscopy diagnostic. Experiments employing this instrument to investigate
the use of line-ratio measurements of Ni- and Co-like transitions in Pd, Mo,
and Nb as an edge electron density diagnostic are scheduled for this week.
Roger Richards from ORNL was here last week working on his ion-tail laser
scattering experiment.

Miklos Porkolab attended the TPX Council Meeting at PPPL. Bruce Lipschultz
attended the TPX Physics Advisory Group Meeting at PPPL. He also presented a
summary of M.I.T. Activities in support of TPX.