Minutes of the March 18,
2004 Tracker Meeting
Action Items:
-
Martin:
send out the bottom tray assembly drawing check prints
-
Martin:
send the bottom tray closeout drawings out for release
-
Riccardo:
check Plyform drawings against the latest releases for mid-tray production
-
Jeff:
update the COI PO to get the bottom tray closeouts machined
-
Martin:
send Sandro known constraints on the MCM mounting pin head
-
John
Ku and Mike Opie: draft or redlined static and vibe test plans
Agenda:
- Thermal-vacuum test update
- Contact needed in Italy for Jeff Tice regarding database of
tracker parts and materials
- Maximum sidewall panel thickness
- Control of drawings for tray production in progress; what to do
with drawing-checker comments
- Assembly procedures and PRR for bottom/top tray panel production
- Bottom tray status:
* closeout and assembly drawings
* closeout machining
* titanium
* assembly tooling
* static test system & visits to Italy
- Status of MCM integration testing at G&A
- Bias circuit status
- MCM production status
- Flex-circuit cable status
- A.O.B.
Nicola reported that the
thermal/vacuum data analysis is in progress and first results will be reported
at the meeting next week. See the Bari
website for thermocouple data.
Work is going on in Pisa to
understand the problems seen during the test with fluctuations in power, but
they have not been able to reproduce the problem so far.
Robert clarified that the “dummy
TEM” used in the test resembled a real TEM only in the shape of the aluminum
box. The resistor divider circuits for
reading the thermistors was copied from the actual TEM schematic, but all the
power distribution was ad hoc. The real
TEM has a power supply sitting on its back, whereas the current for the dummy
was supplied through long wires from an external power supply. Dave Nelson reported that they tested the
thermistor readout in a real TEM at SLAC, connected to 36 real MCMs, and the
thermistor readout did not change when the MCM power was turned on and off.
Nanda confirmed that Pisa received
the 10 preproduction MCMs from SLAC, with 2 burn-in cables, but they have not
yet tested them.
Jerry reported that 50 bias
circuits should be arriving at SLAC today from Parlex in San Jose. SLAC will CMM 2 of them. They should ship to Pisa today or tomorrow.
Jerry is trying to get the
PO placed for the 1/4-oz circuits.
Probably they will be received at SLAC 3 weeks after the PO is in place.
Parlex will then ship 50 per
week until done.
Darren wants us to hold an
MRB on the issue of trace extensions for plating.
Sandro said that the contact
person in Italy for Jeff Tice, for accounting of parts and materials, is Mirco
Bagni.
Sandro reported that the maximum
sidewall thickness measured on the EM panels was 1.57mm, including the
50-micron aluminum. Sandro will send the
detailed data. Robert said that for the
COI test coupons the maximum was about 1.60mm.
Ben Rodini has specified a maximum of 1.63mm in the procurement
document.
Sandro reported that G&A
is producing the tools for the MCM mounting tests. G&A made the first measurements on the 7 MCM boards
yesterday. Sandro will send the results
to SLAC after G&A rechecks the locations of the mounting holes, which
looked in error. The LAT drawings change
only in the mounting pin. Tray mockups
for this test will be ready in 2 weeks.
In 3 weeks the first tools for MCM mounting will be ready. It will allow horizontal adjustment such
that any pitch error can be split from the center. Sandro predicted that G&A will be ready for production at the
end of April.
Martin reported that the bottom
tray assembly drawing check prints will be available tomorrow or Saturday. Riccardo is waiting on them in order to
verify the bottom tray assembly tooling design.
Martin also said that the bottom
tray closeout drawings will go out for approval today (this got delayed a
little later in the day by some redlines that came in from COI).
He also pointed out that we
need to change the insert epoxy callout for the mid tray closeout assembly
drawings. It should be Hysol 934NA,
which is what Plyform is actually using.
Martin noted that all
drawings released from now on for flight-article fabrication will be stamped “Released
for Flight”. This is not the case,
however, for drawings already released, for the mid trays, for example.
Regarding the mid-tray
drawings, Riccardo is going through the drawings used by Plyform so far in mid
tray production and checking them against the latest releases. For example, Plyform machined some inserts
and closeouts last September (using drawings transmitted by SLAC that were
released at that time---most of the mid tray drawings were released at CDR time). The reader may recall when flight tray panel
fabrication was supposed to begin in September 2003. There should be no dimensional changes made to the mid-tray parts
since then, but some notes may have been added to the drawings. Riccardo will then transmit the latest
releases to Plyform. He will also look
for any redlines made by Plyform to these drawings, or any inconsistencies
between the drawings and the actual Plyform procedure, and will transmit this
information back to SLAC for the corrections to be made.
Sandro asked for a schedule
on the bottom tray closeouts. Jim said
that Jeff Tice will work the COI PO.
Robert said that it needs 2 line items added to it for machining of the
closeout parts. This machining needs to
get started next week, but first the drawings need to be released, the PO needs
to get to COI, and Martin needs to talk through the drawings with Toan Pham at
COI. COI will deliver the first 2 sets
of closeouts in 2 weeks ARO.
It was noted that the bottom
tray insert designed changed, so Plyform will have to remake the bottom tray
inserts.
There was a question on the sidewall
insert status. Robert believed that
SLAC had manufactured all of them for the flight build, but Martin is seriously
considering reducing the thickness, in which case they need to be
re-ordered. This is a SLAC
responsibility.
Martin needs information on
the pin for MCM mounting, to make sure there are no conflicts. Martin will send Sandro his known
constraints.
We discussed a schedule for
Erik Swensen and John Ku to travel to Pisa to help with the static test setup. They should arrive on March 31. At that time they also need to discuss
static testing and vibration testing in general. SLAC needs to produce a static test plan of reduced scope, and also
a vibe test plan. John Ku and Mike Opie
are responsible. They need a draft or
redlines of the current drafts before going on the trip.
Mike Menning explained that
they have been going through tolerances in detail, including clearances,
machining tolerances, Grid contributions, thermal movement, dynamic motion, etc. They find that there is lots of difficultly
making the concept of 3 concentric cones work.
An alternate plan has been identified that involves the use of eccentric
cones everywhere. This will cause lots
of pain on both sides of the Atlantic.
Mike will prepare charts for an 8:00 am Monday telecom.
Action Items from Last Week:
1. Jerry:
submit an NCR on the extended traces for plating the 50 bias circuits (in work)
2. Darren:
notify the software development team of the implications of the bias circuit
NCR (done)
3. Robert:
write a statement on the science impact of the heavier copper
4. Sandro:
respond to Robert and Jerry on the options presented for avoiding trimming
through bias circuit traces (done)
5. Jim: find a
designer to revise the static test and vibe test tooling for the new interface
(April 1?)
6. Riccardo:
give Robert a breakdown on the 20 trays expected March 29 (discussed with
Sandro yesterday)
7. Riccardo:
send a sketch of the thermal strap concept to Mike Menning (done)
8. Martin: send
check prints on the bottom tray assembly and closeout assembly to Riccardo
(next day)
9. Riccardo:
send Martin information on the grounding tube diameter and tolerance and
adhesive to Martin (done)
10.Riccardo:
resolve the TBDs (best guesses at least) in LAT-TD-01918 and send to Robert for
release (in progress)
11.Robert: send
Mike Menning a schedule need date for the revised static test fixture (done)
12.Jim: contact
Erik Swensen regarding his possible availability for travel to Italy (done)