Minutes from the meeting at SLAC on 20 April 2000 
present: Alec, BJ, Derek, Eduardo, Gary, Gwelen, John, Ossie, Takanobu 

1) We agreed on the recent design from SLAC on the ladder jig. Alignment 
pins will be made of 
glass filled Delrin and a camera and a rail to move the camera will be 
attached for visual inspection of the fiducials or detector edges. 
The visual inspection will work as a cross check since we still rely on
the 
alignment using the edges. Visual inspection will also verify the
thickness and
completeness of the adhesive bond line. The fixture will 
also accomodate independent vacuum lines. We decide to have 4 posts and
the 
center post will be added 
only if needed (although lines will be physically present). The base
plate
thickness will be increased to 1 in. and will be made out of Al tooling
plate.
If the fixture needs to be put in an oven the base plate could be made
out of
Invar, but would cost more to manufacture. 
2) The gluing dispensing procedure will be made using ideas from both
SLAC 
and UCSC. John is developing a  system (mostly based on the old one) to
create
a thin and controlled layer of 
    glue. The positioning and dipping of detectors will use the method
suggested by UCSC.
BJ will draw and John will prototype the glue dipping apparatus. Concept
drawing will come at next week's meeting. 
      It was noted that the new detectors are too large to be held on
their
edges by hand. The general handling concept for now is
1.                                    Slide out of envelope onto table
2.
Remove paper top cover 3. Pick up with special vacuum tool and place on
glue
dipping apparatus 4.   Pick off apparatus with same vacuum pickup and
place on
ladder jig. Details will come in drawings, too hard to explain by email.
For
this week's meeting we will have conceptual drawings only. 
3) Eduardo reported a conversation with GLAST material engienneer taht 
strongly suggested we move away from UV systems (he will 
give us more feedback as soon as possible). 
4) The fixture/procedure for aligning detectors on trays was discussed.
We
converged on a concept incorporating SCIPP's overhead CCD camera for
edge or
fiducial alignment and SLAC's vacuum platen to hold detectors in X,Y,Z
while
curing. We discussed applying adhesives in a way to minimize trapped
air. No
one was identified to lead the search for the adhesive(s) to attach
detectors.
John agreed to present a concept drawing for detector alignment using a
platen.

5) It was agreed that we need a minimum of 32 mechanical detectors to
adequately test the first jig (ideally 50-100). Eduardo said he would
investigate the availability of 9.5 cm. square detectors for
prototyping. If
there are not enough available we will design the first jig for 6.5 x
10.6 cm.
detectors which are more available. 

Action lists: 
1- BJ and John will complete the drawings for the jig and the glue
dipping
apparatus 
2- Eduardo will send more info to GSFC to help in settling the UV gluing 
issue and get requiremenst document written. 
3- Ossie will investigate localized heat curing as a fall back solution
for 
UV. 
4- Ossie will try to measure flatness of mechanical silicon wafers using 
gauges to undrestand if a center vacuum post is needed.
      5-Eduardo will find out if we can get at least 32 6.5 cm. square
mechanical detectors