Re: Test Setup (From Fernando)

[Elton Smith <elton@jlab.org>]

-------- Original Message --------
Subject: Re: test setup
Date: Mon, 14 Apr 2003 15:18:46 -0400
From: "Fernando J. Barbosa" <barbosa@jlab.org>
To: "Mehmet Bektasoglu" <mehmet@jlab.org>
References: <3E91BD60.4040106@jlab.org> 
<004601c2fd3a$503c6120$3e0e3981@jlab.org> <3E9AE2C9.1070905@jlab.org>



Hi Mehmet,

    I  only tried to make a simple test setup so you could use conductive
epoxy in a manner similar to what you should have on the real detector, I
didn't actually use any conductive epoxy. Given the fact that you wanted to
test signal characteristics and the impact of epoxy on the signal quality,
it would be almost impossible to do something meaningful, short of designing
a short section of the real detector and have it fabricated. You will have
the real thing earlier from Randy.

    As for the soldering, actually Elliott suggested it. I think it is a
great idea because it is simple, robust and free from any drawbacks.
Components are routinely soldered to Kapton on a whole range of commercial
products. The idea is to have the detector output traces routed to the edge
on the Kapton. The Kapton foil is then glued to the frame printed circuit
board (PCB) so that the Kapton traces line up with those on the PCB and then
apply solder to form a fillet from the Kapton to the PCB. This is simple,
robust and can be easily reworked. There is no real reason to use conductive
epoxy on this application. And because this is standard practice, you don't
have to do any research on it.

    I would strongly recommend that you perform the real study on the real
Kapton and PCB that you will get from Randy. You might ask Randy to get an
additional set of these from the manufacturer for you to play with before
assembling the real detector.

    I have finished the preamp board and I have attached two pdf files:
FDCPA shows the dimensions of the board, which I also forwarded to Randy for
his design of the detector and FDCPA_SCH shows its schematic. This PCB will
be out for manufacturing sometime this week. I have designed the board so it
can be used for both the sense wires and the cathode strips as the preamps
accept both positive and negative current signals. The output connector will
be assembled in either of two positions: one for sense wires (negative input
currents) and one for cathode strips (positive input currents). In this way,
the output polarity will always be in the same correct arrangement for
connection to post amps. I just received a new batch of preamps for this
detector that are conformally coated and should prove to be impervious to
any environmental conditions.

    From your drawings, I believe you have 32 cathode strips on the u-plane,
16 sense wires and 32 cathode strips on the v-plane. We would need 5 preamp
boards (16 channels each) but I will order 2 additional for spares. Let me
know if this count is correct.

    Let me know if you have any additional concerns. best regards,

        Fernando

Fernando J. Barbosa
Jefferson Lab
MS 6B
12000 Jefferson Ave.
Newport News, VA 23606
barbosa@jlab.org
757-269-7433



-- 
Mehmet Bektasoglu

Post-Doctorate Research Assistant
Ohio University, Department of Physics & Astronomy
JLab Office: (757) 269 5315
mehmet@jlab.org, mehmetb@physics.odu.edu
http://www.physics.odu.edu/~mehmetb

FDCPA_SCH.pdf

FDCPA.pdf