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
May 10, 2002


The cryostat was installed this week marking a milestone in the reassembly
of Alcator C-Mod. Work continued on ICRF, LH MIE, DNB, and diagnostic
systems.


Operations
----------

A successful hi-pot and ring was done this week on all the C-Mod
magnets. This step marks the "tokamak complete" stage of reassembly.
Earlier in the week, all connections between the curved bus and the coax
extensions were completed and inspected. All cooling lines have been
run from the tokamak to the manifold above the bus tunnel. Following
a last set of inspections, the lower cryostat was raised, allowing
access to the lower vertical ports. Installation of instrumentation
below the machine is now well underway. Later in the week both the upper
cryostat and the cryostat cover were installed. A picture of the top cover
being installed can be found at

http://www.psfc.mit.edu/cmod/operations/EngImages/Inspection_2001-2002/Disassembly_Assembly/Machine_assembly_B/DCP_0659.JPG

Three of the new instrumentation ports can be seen near the middle of the
photo. The boots that will soon seal the cryostat are also shown surrounding
the horizontal ports.

Following installation of the rf feedthroughs at D- and E-Hor earlier in the
week, installation of the ICRF antennas has proceeded quickly with final
assembly expected by early next week. The BN tiles have been vacuum
baked at 400C, cooled down, and are ready for installation. The TORVAC
pumping station is being brought back online. CAMAC highways and PLC
communications are being brought back up, as are the control room workstations.
Seven more Linux workstations were received early in the week and are now
available for use in the control room. Work on the magnet bus, TF/TC scanners,
and ECDC systems also continues in preparation for the next run campaign.


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

Two engineers from the power supply vendor will return next week to begin
commissioning of the HVPS. Tests conducted at the vendor site indicate that
software problems with the control program have been fixed.

Components needed for the forward and reflected power measurements have been
selected and are now on order. Work continued on the PLC control system
timing for the up coming transmitter tests, as well as the low power realtime
control system.

The PPPL May Fin Plan Letter has arrived with $300K additional budget
authority for the C-Mod Lower Hybrid Project. This amount is being
borrowed against planned FY2002 diagnostics, which will be deferred,
and will be returned out of FY2003 LH funds. We now have authority
to spend that budget and accelerate the final design and FY2003
procurements for the LH launcher.


ICRF
----

We continue to build up the new racks and control, fault, and diagnostic
electronics for the transmitters. Hi-yard work is ongoing to ready the
transmitter high voltage supplies for operation. New control electronics
for the tuners and phaseshifters is becoming operational.


RFX DNB
-------

The DNB racks, control computer, and PLC were repositioned so that
all the DNB equipment is now in its final position. PLC control and
monitoring is now being done from the control room. Equipment is
now being prepared invessel and on the DNB beam line to align the
beam relative to the tokamak.

The components needed for the LN2 feedline for the DNB and cryopump from our
main storage tank have been ordered with delivery expected in 3 to 4 weeks.
We will continue to operate the beam using LN2 from 500l dewers until the
new line is installed. All gas delivery components are in-house, and the
beamline duct that connects the beam to Alcator C-Mod is undergoing leakchecks.


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

Installation and alignment of CXRS, MSE, and BES invessel
optics has been completed. Spatial calibration is partially complete.
All calibrations will be completed next week.

The MSE diagnostic image dissector has been returned to MIT from PPPL.
This is a new design that is much more efficient optically and operationally
than the original image dissector, and is the last of the modified
optical system components.

The bolometer array at K-Hor was re-installed this week and will be
calibrated over the next few days.


Travel and Visits
-----------------

Matt Sampsell, UT-FRC, visited during the week and assisted
with the invessel installations.

Stew Zweben, PPPL, worked on the Gas Puff Imaging diagnostic at MIT 5/9-10
and gave a seminar, "Edge Turbulence Imaging In Alcator C-Mod and
NSTX," on 5/10.