Minutes of the Tracker
Meeting
July 1, 2004
Action Items:
1) Nicola et al: status of the T/V test preparations and thermal
stabilization of the TEM/PS:
Nicola reported that in Bari
there is a web page for Tower A T/V.
Drawings of the test hardware will be available next week, including a
configuration drawing of the test setup.
The solid model can be seen on the web page. The long TEM cable is in Pisa to label the wires, since SLAC did
not label them adequately. Procedures
for the T/V test are in progress.
Nicola expects to use the same team as for the EM test.
Nicola asked whether the SSD
bias can be turned on at the max temperature of 50C, to perform a CPT. Robert said that although the test may not
meet noise requirements, there should not be any danger of damage from the
leakage current, which would be about 8 times the room temperature current. But he wants to verify this with Si experts.
The long PDU cable for T/V
testing is missing. Pisa will check for
it in customs. Jeff will ship over two
more.
2) Tower functional test preparations and support needed from SLAC:
Luca said the need the C0
cables, they have 2 test stands working and 2 more in customs. Robert reported that just 6 C0 cables will
be sent, with connector savers. 3
others had to be returned to Parlex because of manufacturing defects.
We identified a need to have
a cable tester in Pisa. Robert will
look into what SLAC can send.
For the test support Pisa
needs some people from online, such as Rick or Selim, plus maybe 1 from the
electronics group. Persis will check on
availability. The best time for them to
be there is when the tower is assembled.
Luca reported that the
stacked tray and tower level test procedure documents need updates and
release. He and Hiro and others are
still discussing feasibility of a couple of performance tests that may be
better performed at SLAC after tower delivery.
Persis recommended that we identify a minimal set of tests that
absolutely must be done before environmental test.
3) Martin: Lifting Fixture configuration change
Martin explained his reasons
for changing the design back to the flexure concept. We cannot tolerate having shoulder bolts bearing down on the
inside of the top tray closeout. The shoulder on the shoulder bolts was
actually smaller than the hole for the inserts, meaning that the shoulder would
bear down on the epoxy at the end of the insert and have an unknown effect on
the insert and bolt. We could add a bearing plate on the closeout, but that
seemed like a poor fix to the problem.
Martin incorporated Emilio's suggestion to use bolts running vertically,
loaded in tension. This also allows one
to adjust the flexure position to minimize the amount of flexing. Flexures can be installed first onto the
tray and then put on the plate, if needed.
There are 4 lifting eye nuts around the corners and 1 more in the
center. Martin added balancing weights,
which are optional. He and John will
complete the stress analysis today.
Tom Venator offered help
from the Goddard shop to make some of the MGSE.
4) Dave: Request fit check of MJ2.5 x .45 x 120 Counter sunk screw
into Aluminum and Ti. Inserts to ensure fit with M2.5 female thread. We successfully performed a fit check of the
MJ2.5 x .45 x 120 Counter sunk screw into a M2.5 commercial nut and there were
no issues with interference. If
Sandro's fit check works as well, I would like to claim victory and use
existing qty. 13,500 screws that INFN has for flight:
Dave said that the J denotes
a special root thread form (softer radius), but they found that the threads
worked fine in a standard nut. He Would
like Pisa to check these screws in an actual insert (Al and Ti). It turned out that that had already done,
with no problems found.
100 degree screws: Jeff
located a supplier and hopes to have them a week from Friday. Martin will release drawings of the screws.
Pisa also needs Torx+
screwdrivers. Robert suggested getting
screwdrivers with a built in calibrated torque setting.
5) Dave: Discussion of INFNs Tower Turn-Over Fixture. Understand concept and required
interface.
Emilio said that the info on
this fixture is in the procedure. It is
to be used after installing the grid simulator and cable plate. The CPT tests will first be done with the
tower upside down.
The rotation tool is in
production. It attaches to the grid
simulator and cable plate with 8 bolts.
They will send drawings to Martin, including 3-d pictures.
Martin needs more info about
the asymmetry in the grid simulator that was noted by INFN. Marked up drawings would be best. It was noted that the existing fixture used
for the EM vibe must have this asymmetry, since it was built to those drawings
(or the solid model from which the drawings were produced).
An analysis and proof load
test of the turn-over fixture is absolutely required. John Ku can review the analysis.
6) Dave: Closure on Inner container design.
We decided to hold an 8:00
meeting Friday; Dave Rich will send out an agenda and call-in number.
7) Martin: What bottom tray grounding lug is being provided?
Sandro will go to G&A
tomorrow and check on the status. Martin
will release the drawing today. Material is in procurement at G&A but
nothing built yet.
8) Sidewall fabrication: release of the spec document
Defered until Riccardo's
return from Plyform.
9) Tray assembly at G&A: release of the drawings and procedure
spec
Sandro has reviewed the
drawings. He had a few comments, but I
think the conclusion was that they can be incorporated as redlines or in the
next release.
Sandro said that the
encapsulant height limit should be 0.7mm.
This is higher than the requirement on ladders because very little
dynamic clearance is needed near the tray edge, and there is no opposing
encapsulation line at the location on the tray above.
10) Tray panel assembly at
Plyform: schedule projections for Tower A and mass production
Sandro noted that there are
2 problems preventing start-up:
- Kapton bonding issue
- Bias circuits. Robert emphasized that there is no
quarantine on any of the bias circuits, so that should not hold up start of
production. However, to minimize risk
in using circuits in parallel with NASA coupon testing, the circuits should be
used first-in-first-out.
Sandro said that the last
shipment of circuits is stuck in customs; there is a problem with serial
numbers.
11) A.O.B.
Tom had some questions:
- COI certs. Dave said that the certs were faxed to
Plyform yesterday. A duplicate was
forwarded to INFN.
- Hex nut locking
mechanism. Arthur is picking up studs
and verifying that they work with the patch, using actual hex nuts. Any change of the design to use epoxy
instead requires consultation with I&t.
- TQCMs for thermal vac: has
SLAC agreed to purchase them? Robert
will talk to Jack about this. Nicola
said that there may be an issue of feedthrough availability. He will check on that.
Nanda said that we need to
schedule a new delta-TRR for the bottom tray static test procedure to review a
couple of changes identified as being needed.