From: irby@PSFC.MIT.EDU
Reply-To: IRBY@PSFC.MIT.EDU
Subject: Alcator C-Mod Weekly Highlights
Organization: MIT
Newsgroups: sci.physics.plasma


Alcator C-Mod Weekly Highlights
October 05, 2001


The inspection of Alcator C-Mod continues. The Lower Hybrid High Voltage
Power Supply has been delivered to MIT and work continues on ICRF systems.


Inspection
----------

Both upper OH coaxes have been removed from the machine after careful
measurements of the torque settings of all six bolts securing each coax
in place. Analysis of this data is proceeding. The condition of the
feltmetal used in the coax connections is in an as installed
condition. A small number of silver plated TF joint fingers show a
frosted appearance that we are investigating. These surfaces had a
polished appearance before the last assembly. The frosting indicates
some wear of the plated surface. We will continue disassembly
next week to reach the lower horizontal arm connections to the TF core and
the OH2L coax. Disassembly will be complete at this point.


Lower Hybrid MIE Project
------------------------

The Lower Hybrid High Voltage Power Supply arrived at the shipping company
yard on Wednesday morning. Hans Kalt, an engineer working for the supply
vendor , Monty Grimes, and Dave Terry went there to inspect the shipment,
supervise the unloading and reloading of the containers on the
trucks, and supervise the uncrating of the transformers and switchgear.
The power supply arrived at MIT on Friday. The switchgear and transformers
were the first to be setup. The lower container was set in place next and
finally the upper container. The outside stairway to the upper container was
also installed. Wiring of the components inside the containers will begin
next week. Pictures showing the switchgear enclosure and the high voltage
transformers after they were craned into position can be found at

http://www.psfc.mit.edu/cmod/operations/EngImages/RF/lower_hybrid/P0002154.JPG

Pictures of the upper enclosure being lowered into position and the final
assembly with the stairway can be found at

http://www.psfc.mit.edu/cmod/operations/EngImages/RF/lower_hybrid/P0002167.JPG

and

http://www.psfc.mit.edu/cmod/operations/EngImages/RF/lower_hybrid/P0002172.JPG

Installation of cable trays, interface boxes, and water cooling piping
for the lower hybrid project continued this week.

Wiring on the transmitter equipment racks is proceeding. A wiring harness to
test the control system with the carts is being fabricated. Tests of the TPS
RF boards were begun. Assembly of the HV Junction Box Optical Interface and
Relay Driver Boards was completed.

A temporary breaker control panel for the HVPS tests has been fabricated.
A conduit has been run from the HV control panel in the power room into the
LH development lab to allow power supply tests to be conducted from there.
The control cable has arrived and we will pull and connect it early next week.

Error checking and handling programs for the active controllers are being
developed.

C-Mod engineers met with contractors working on the Lower Hybrid water system.
Much progress was made finalizing the transmitter water manifold interface.


ICRF Systems
------------

We continue development of the new phase detector boards. A choice between
a down-conversion technique and application of an extremely fast XOR chip
will be made in the next few days. Work also continues on models of the
antennas, transmission system, and cavities.


Inner Divertor
--------------

The invessel fitup of the new inner divertor has been completed successfully.
All measurements have been made needed to complete final machining of the
components and to have the inner surfaces silver plated to enhance thermal
contact to the inner wall. All components have been delivered to the
vendors and are all expected back by the end of the month. Work at
MIT will now concentrate on the installation of the studs. Before being
shipped out, the inner divertor was assembled in our machine shop as one
last assembly test. A picture of the assembly may be seen at

http://www.psfc.mit.edu/cmod/operations/EngImages/MACHINE/Divertor/P0002145.jpg

Mike Demaria on the left, our design engineer, and Jim Zaks, divertor project
lead engineer, are shown standing over the divertor. Measurements indicated
a variation in the inner ring diameter of less than 0.005", well within
the tolerance required to maintain efficient heat conduction into the inner
wall.


Diagnostics
-----------

We are considering modifications of the CXRS views to emphasize more
accessible and possibly more interesting regions near the plasma periphery.
We continued to identify improved spectrometers (for higher throughput) and
detectors (for sensitivity and readout speed) for CXRS, and to optimize the use
of one or two spectrometer/detector instruments to record spectral
information from a number of plasma regions. The BES team continued with
redesign of the BES/MSE optics including optical simulations and significant
mechanical changes for the internal optics to simplify installation and
improve measurement

At PPPL, work continued on extending the reflectometer wave propagation
calculations to include the effect of poloidal field shear.

DNB
---

We continue to evaluate the RFX beam and its effects on beam related
diagnostics. A first meeting was held this week at MIT to discuss site
preparations for the beam. An extensive email dialog is ongoing between
C-Mod and the INP team in Novosibirsk. A new engineer will begin work on
the beam project next week (UTexas employee to be stationed full time at
MIT).


Trips and Visits
----------------

On Tuesday, Hans Kalt, an engineer working for the vendor providing the LH
High Voltage Power Supply, arrived to prepare for the power supply
installation. He will be here until the end of the month supervising
installation of the supply.