Date: Wed, 20 Nov 2013 17:11:05 -0800
From: "Segal, Julie" <jsegal@slac.stanford.edu>
To: "<john.flanagan@kek.jp>" <john.flanagan@kek.jp>
Cc: Gary S. Varner <varner@phys.hawaii.edu>, "Kenney, Christopher J." <kenney@slac.stanford.edu>, "Hasi, Jasmine" <jasmine.hasi@slac.stanford.edu>
Subject: Re: for today's meeting - follow up

A couple points to follow up from today's meeting:
1) John's simulation results suggested that 25um strips might not
give much of an advantage over 50um strips in terms of resolution. In
addition to having 1/2 the read-out channels, with 50um strip pitch
we wouldn't need any fan-out to the bond pads.  This would have two
benefits:
a) the capacitance would drop from 1.5pF-3.0pF depending on location
to 0.7pF for all strips (the bond-pad capacitance, mostly)
b) smaller die size and no metal routing would improve process yield

2) For the spectrometer: I gave capacitance numbers based on
splitting the metal capacitance evenly between the first (smallest)
and last (largest) strip, resulting in 2.0pF for the smallest, 3.4pF
for the largest.  I could move the pads toward the largest strip to
split the final capacitance instead, giving 2.7pF each. Or somewhere
in between, or we could make it more uneven if we wanted to "favor"
the smaller strips.  Gary, do you have any feedback on this issue? We
can discuss next week.

- Julie