Minutes of the Tracker
Meeting
disclaimer: all time estimates referring
to work being done “next week” are probably delayed by the new stand-down and
safety training.
Action Items:
1) Cable-3 problem update:
- The problem will be investigated further after tower
disassembly. The situation at present is
that we know it to be a problem with the connector on the top MCM, not a cable
problem. The MCM was a preproduction
one, which has had a lot of use (but always with connector savers
attached). There may have been some
damage in the cable installation, perhaps due to the fact that no bending tool
was available for that cactus arm, making it difficult to mate and putting a
lot of stress onto the connectors. We
have to have the bending tool for Tower A!
Also, there needs to be some stress relief in that area, provided by the
sidewall (i.e. foam or O-ring between this cactus arm and the sidewall).
2) Tracker test temperatures
& document update & release
- Nicola Mazziotta will update the tray thermal test plan and
procedure to go up to 55C (used to be 50C).
Done.
- Francesco Belli will update the
tray panel T/V test plan to 60C (officially used to be 85C). Done.
- Robert will ask Natalie to re-release both. Done.
3) Bias circuit coupon
testing closure plan
- Dave sent out a new drawing for approval, and Nick has signed
off on it. The notes have been changed
such that no via contact is required, and therefore no coupon testing is
needed. Once released, this will recover
all of the bias circuits presently on hold.
4) Tall MCMs for Tower-A
- Robert will hand carry 5 of them to
5) Flex-circuit cables
- Almost all of the original Parlex production has failed one
coupon test or another. This casts just
as much suspicion on those that did pass, since the pass could have been
fortuitous and does not necessarily mean that the vias in the actual cables are
good.
- All vias tested by GSFC from the new, improved Parlex process
were good.
- Our hope is to get a new Tower-A set by the end of October,
so that we can test them and ship them to
6) Closure progress and plan
for other Tower-A issues:
- Solithane – Jeff said that the
- Nusil silicones: the
- ball nests and fasteners: magnets
and clips are getting epoxied in. Fasteners are on order for next week.
- studs and other I/F hardware: 410 studs are being dycronited (Friday); 50 hex nuts are also being dycronited; all cones and hex bushings have been
fabricated; Arthur plans to pull 10 parts of each and do tests on running
torque. Then he will go to Nyloc with the new parts and will stay with them until we
have a procedure that works every time.
Every stud will be run in on both ends at SLAC, using flight square and
hex nuts.
- custom socket wrench for studs:
Peter is working it and will test it with Arthur
- cone extraction tools: Peter is working
it (a couple will be here next week; they are presently in the SLAC shop)
- cable holding plate: all 18 are at SLAC; SLAC will do fit
checks with the inner shipping containers and ship together the whole assembly along
with the outer shipping container, in time for each tower.
- new clips for cable holding plate: they
will be in next week; 50 of each are on order
- ESD caps: 1 week lead time, Jeff will order them off the
shelf with a credit card
- corner brackets: will be completed
tomorrow but then need a complete inspection
- clips with rounded corners and
Kapton tape: same time frame; Jeff needs to order tape (check with I&T)
- outer shipping container; will arrive at SLAC next week; then
SLAC will qual test it the next week; Steve said it could be at INFN in 2 to 3
weeks, but to make it work we need manpower put on this.
- inner shipping containers; 1 set due
Oct 16th; the remainder to follow by mid November
- base plates, including grounding
screw: these are in hand, and we will add grounding screws at SLAC; 1st
is due October 18th
- cable bending tools, normal and top:
Arthur said that this is in progress; the redesign is mostly finished on the
old one. The new one will be ready today
or tomorrow. They will be in the SLAC
shop next week.
- long screwdriver bit; Jeff procured
assorted extensions; Robert will carry them to
- heat straps and tie-downs; all have
been made; a set of 3 is being CMM’ed
- cable strain relief: Jeff will call
Fred Gross about what sort of foam can be used.
Done.
7) Questions from Steve:
1. Is it possible to use
the Digi-torque for the installation of items 37
& 38 on LAT-DS-00722 rather than purchasing additional new torque
screwdrivers? Is a special torque driver
needed for top corner brackets? Answer:
2. Discussion of problem
with removing the bottom row of screws Item 27 on LAT-DS-00722. Does torque
value need to change? Does bit fit correctly? Are there enough bits to replace worn
bits frequently enough? The custom screw
lead time is 3 to 4 weeks. INFN will
investigate these issues and report next week.
Done.
8) G&A production
readiness: drawing and procedure document mods? Martin said that drawings will be done
probably Monday. Sandro will review
results on the 3 test articles tomorrow.
9) Other business:
- Closure of any remaining
Tower-0 NCRs and a Tower-A
assembly PRR: we need to schedule a review date around the first of November.
- Return of the EM tower: it
is in the shipping container; Monday morning it will ship to SLAC
- Prepreg in
- Sandro sent info on the CC
bars. More material would be needed Feb
or March. Alcomp
is 3 to 4 months lead time.
- ESD sheets are needed in
- Foam or pads: is there any
closed-cell foam that doesn’t particulate; Jeff will send information.
- Desiccant bags are needed.