Minutes of the Tracker Meeting
October 23, 2002
Plyform completed only 2 sandwich
panels. Ricardo will install closeouts
in them tomorrow. Next week they will
change to making light trays and will make 3 trays. Plyform received drawings and materials for the top tray. Sandro will ask them to do a set of
closeouts in aluminum first, as there is no extra carbon-carbon material. In Italy there are 4 honeycombs to make
top/bottom trays. Sandro suggested that
they could make a top tray with the aluminum closeouts for use on the bottom of
the live tower.
The Kapton assembly tool still being measured
at Pisa. The tungsten tooling still is
being revised to fix two reference holes.
G&A plans to start next week building new
ladders. Some will be ready for test at
the end of next week.
G&A received the CV2500 glue. The only problem with it is its
flamability. Otherwise it appears not
to be hard to use. They are waiting for
the CV15-2500 (which is not flammable).
It was shipped last Friday from SLAC.
Nothing is presently going on at Mipot. They are waiting for the right set of glues
before making more prototype ladders.
G&A promised that next week they will do
the first wirebonding tests on the mockup MCMs.
Teledyne is doing the final process
evaluation for the MCMs. There is some
concern that the glop-top epoxy has a 150C cure, which can cause warping of
boards. The die attach glue cures at
80C. They will try the same temperature
for the glop top. They will also look
at CV15-2500. Robert asked if this
would give enough protection. He recalled
that the BTEM MCMs were encapsulated with a silicone material, and some wire
bonds in the region of the cables were eventually damaged by handling. Teledyne will bring two MCMs to SLAC next
week. There is still some concern about
air bubbles under the pitch adapter that may cause wire bonding problems at
G&A.
Data Circuit Systems is rerunning the
MCMs. Only 6 delivered out of the last
batch because of a processing problem.
Robert said that the problem with the
oscillation of some of the G chips has been more-or-less understood, and a fix
was found and successfully tested by FIB.
The EM GTRC chips are diced and in hand. The tested and diced GTFE chips will come
back on Tuesday fully sorted. They can
then be shipped directly to Teledyne.
The mini-MCM was received in Pisa, but the
test system has not yet arrived.
Luca is arriving next Monday at 6:15 at
SFO. Tom can pick him up. He should call Tom's cell phone upon
arrival. Luca said that he can do some
work with Mutsumi following his trip to Hawaii, or at SLAC next week. He recommends to send software for the test
system to the student in Pisa asap.
The contract for bottom-tray work finally
went to Hytec. The titanium gusset
design and test plan are in place.
Ossie reported that a physicist is arriving
at SLAC to make measurements on rectangular invar frames assembled by
Ossie. Ossie made a plywood substrate
to support them. Results can be had by
the end of the week, hopefully.
Ossie reported that heat treating the frames
caused the material to deform. The
deformation was enough to break welds in some cases. It is a very springy material.
Also, it was rusted when it came back from the heat-treat vendor. Plating will probably therefore be
necessary. Erik will talk to the invar
specialty shop about these issues.
Sandro said that customs is holding up
shipment of ladders. Paperwork was not
renewed after one year for the temporary importation of the SSDs.
Sandro needs to know if we can we use old
face-sheet material for flight production?
How can they be requalified?
What parameters need to be checked?
Tom said that he sent the questions to Erik. They are stored in a freezer at Plyform. The expiration date was 6 months after
purchase. Tom will call Fred Gross at
GSFC about this.
The top tray assembly tool is at SLAC. There is a conflict in the CMM area; there
is no operator. Ossie is busy with
invar testing. The insert tool should
arrive today.
Erik said that Franz noticed an error in a
calculation and now says that the tower-to-tower deflection requirements
requires a 190 Hz lateral resonance frequency for the tower. This emphasises a need to review the random
vibe spec. We need to know what
spectrum will be used in LAT testing and whether notching will be done. Erik will try putting corner gussets and
angle braces into the model. We
discussed using the thicker 6-ply face sheets and the heavy core in the bottom
tray.