GLAST Tracker Technical Meeting Minutes

Wed. 1/24/10

 

  1. Gwelen and Tom described some of the interesting things they saw at the Apex trade show, such as electric torque limiting screwdrivers, silver filled silicones, and vacuum pickup tools for wafers.  More information is in the mail and will be forwarded to interested parities.

 

  1. Gwelen asked about details of the Kapton cable, tower interface.  Some issues are around the top tray and how the cables bend over the top of the tray.  Another issue is the area where cables interface to the MCM.  Gwelen will work with BJ and Dave Nelson on a more complete drawing of the 8 cables and how they interface to the top tray.  Hytec will try and make a drawing of the top tray.  As soon as we have these drawings, there will be a telecon to discuss them.

 

  1. Sandro and an engineer are arriving at Hytec next Wed., Jan. 31st at 2:00 pm and will leave Friday afternoon.  Tom and Erik will put together an agenda for the meeting.

 

  1. Hytec reported on the status of their work.  Starting next week they will begin sidewall (shear out) and coating testing.  AlComp has had another delay in delivering C-C material and has said that it will arrive at the end of the month.  Tom asked about the potential use of the Italian C-C material.  Erik said the material properties look satisfactory.  Tom suggested ordering some in Italy for future testing alongside AlComp material.  He mentioned the merits of having an alternate vendor and especially one closer to Pisa.  Hytec is working hard on completing the drawing package of the tray assembly tooling so they can send it out for quotes.

 

  1. Ronaldo and Tom discussed some details of the budget. 

 

  1. Sandro presented results from detector testing.  The mechanical dimensions are well within the quoted tolerance.  All the detectors were cut the same way, to within the measurement precision of a few microns.  The dicing square is larger than the nominal value by 10 microns and is rotated 8 microns relative the fiducials.  He measured the pitch at exactly 228.00 microns.  I-V values agree with Hamamatsu data.  He measured inter-strip capacitance between 1 strip and its 2 neighbors.  Hartmut mentioned that the standard test should be between 1 strip and its neighbors instead of the previous plan to test 4 strips.

 

  1. Sandro said that their models of the trays show 200 micron bending at –40 degrees with epoxy used to bond the converters and detectors.  Using silicone to bond the converters and detectors had worse bending of ~400 microns at –40 degrees.  They are working next on a model using epoxy for the converters and silicone for the detectors.  They are also going to change their dot pattern for bonding the detectors to the one that Ossie has proposed.  The stress in the detectors is about 10 Mpa (1400 psi).  Gwelen pointed out that the bowing will give an uncertainty to the Z alignment due to temperature variations within the operating range.   Tom will look at the numbers with Eduardo, although everyone believes that there won’t be a problem.

 

Action Items:

  1. Gwelen and BJ: work with Dave Nelson on the cable drawings and interface with the top tray.
  2. Hytec: make a drawing of the top tray.