Minutes of the February 17 Tracker Meeting
1) MRB (see the table of NCRs below)
2) MCM inventory for Tower 3
NCRs 283,377,399,400: these MCMs all exceed the documented requirement for maximum number of dead channels per layer. The disposition agreed upon is to use them as is. See the 1st February 17 presentation on http://glast.pi.infn.it/GLASTtalks.html#MRB.
NCR 385: A resistor got damaged on
one MCM mounted on a tray. See the 1st
February 17 presentation on http://glast.pi.infn.it/GLASTtalks.html#MRB. SLAC needs to send resistors to
372: See the 2nd
February 17 presentation on http://glast.pi.infn.it/GLASTtalks.html#MRB. The meeting agreed with the proposed
disposition and corrective action. There
was an open action for
Comments received by email from
1) The proposed pass/fail criteria is okay for me. Based
on observed performance of the bottom tray joints, we can derive acceptable
limits based on statistical reduction of data.
I have discussed this in the past in detail with
2) We looked at the M4x6mm screws together last week and agreed that it provides adequate engagement into the closeouts (no less than the other M4x6mm screws). Additionally, it has successfully passed environmental testing. Due to these two factors, I believe it have been verified by test and no additional analysis is needed at this point. In the future, if there are other substitutions, we should be alerted at or before the TRR so the relative risk can be evaluated.
NCR 374: Riccardo checked during assembly of the sidewalls onto the tower that there was no problem with alignment of the holes between sidewalls and tray, so this closes out all issues associated with this NCR.
MCM inventory: SN 1062 worked at
SLAC but initially a GTRC was not working in
Tower-1 status: the CPT on Tower 1 was done yesterday prior to sidewall installation. It was performed with different test station than was used previously. The power supply was set to 1 amp compliance (normally 3 amps in previous tests). The 1 amp limit was not enough; they need at least 1.5 amp. Luca wanted to make sure this was as expected? Robert will ask experts at SLAC. (The answer is that > 1 amp is needed in order to supply sufficient surge current at power-on. SLAC sets the compliance at 3 amps.)
Tower 1 CPT looks good. There is a link to the results on the
Tower 2 trays are still on track at G&A for completion by next Tuesday. Sandro is at Plyform to verify WIP, including sidewalls.
Dave gave a reminder that Kapton
tape needs to be installed in
NCR’s STATUS –
NCR ITEM TITLE LAST DISPOSITION STATUS
283 Maj Mid 063 18 disconn. ch. Refer to MRB Open
377 Maj Top 006 17 disconn.ch. Refer to MRB Open
399 Maj Bottom 005 19 disconn. ch. Refer to MRB Open
400 Maj Heavy 015 22 disconn. ch. Refer to MRB Open
372 Maj Bottom 005 nut torque loss Refer to MRB Open
374 Maj Bottom 005 Dimensions out of spec. A) Use As Is for Tower “1” Open
B) verify no problem at Tower level
Other (Tower -“2”)
385 Maj Mid 070 GTFE not working Refer to MRB Open
(Resistor R111 broken)