From: Kaushik De <kaushik@uta.edu>
From:   SMTP%"kaushik@uta.edu"  3-JUL-1998 11:26:54.13
To:     GALLAS
Subj:   Re: Minutes - ICD meeting Thursday July 2, 1998 10-noon, 3-4:30pm Ugh

** Reply to note from Elizabeth Gallas - UofTX Arlington 
<GALLAS@d0uta1.fnal.gov> Thu, 02 Jul 1998 20:08:10 -0500 (CDT)

Hi Elizabeth,
        Meeting notes are very well written.  Here are some
answers to your questions:

For the 2 PMT method, 
the Yield = 3D 1/2 (average(PMT1+PMT2)/sigma(PMT1-PMT2))**2, where 
    PMT1 is the ADC signal from the first PMT..., 
    average(PMT1+PMT) is the mean of the distribution 
            from summing the ADC output from the 2 PMT's and 
    sigma(PMT1-PMT2) is the width of the difference distribution.  
It is important to match the two PMT's - which can be easily checked
from the mean of the difference distribution.  If the PMT's are matched,
the mean should be 0.

This test should be done with two fibers.  
However, since we do not mirror (in order to read out with 2 PMT's), the
actual yield in the ICD will be somewhat higher.  
Past studies have shown 25-50% improvement in yield due to mirroring. 
So, if we get a yield of 20, we should be happy.  
(That means the true yield is 25-30, and even with factor of two loss in
the entire fiber system, we will have more than out goal of 10 pe/MIP).

We should measure as many tiles from the 1/2" prototype as possible.
At a minimum, 3 tiles.

When the cosmic test stand is ready again with new electronics for testing
the prototype (the yield test can be done with either electronics - old
is fine), we should do a crosstalk measurement using the scintillator
hodoscope information.

Looks like we will be using Jia's original closed box design after all!
However, the hole diameter need to be enlarged by 1 mm to accomodate the
PMT socket.  
There is no intereference with wire size - should be kept the same.  
The power dissipation is about 2 Watts (including the HV bases).  
The rise in temperature should be checked with 16 boxes packed together.

Currently the calibration system used pin diodes to monitor some of the
fibers.  
However, since the pin diode is not sensitive to low light levels (like
a PMT), we can only calibrate at 100-1000's of MIPS.  
This of course does not provide calibration of the very important 1-2
MIP region.  
APD's, increasing the light to diodes etc should be tried to match the
monitoring of the calibration system to the correct ICD operating range.

Need electrolytic capacitor for LV PS on motherboard.  
May also need fuses (how far is the LV fanout system - is it fused)? 
Check with Dean.  
Put all components on one side.  
Move caps away from base board.  
Add R to HV RC circuit.  
Check diode noise at the anode of the base card.  
Check for other noise by powering up all 6 channels including base &
preamp.  
Dean should approve board before final  production run.  
Final board should have silk screen.  
Inside of drawers should be sprayed with acrylic resistive coating...

                                                             Kaushik