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Message ID: 16     Entry time: Thu Jun 1 10:42:31 2023
Author: Guy Leckenby 
Category: Electronics 
Subject: Summary of Preamp Testing 
MSI-8 and MPR-16 preamps have nominal differential output ranges of +/-1.8V and +/-1.2V respectively at maximum input (ie 5GeV).
All our FEBEX cards are now modified to accept +/-2V range. If serious pileup occurs, this could make it difficult to disentangle events for the n-sides.

To test whether out preamps satisfied this output range, we attempted to calculate the expected height from a 500mV pulser. This should have been:
 input height * (pulser coupling range / preamp energy range) * nominal output range

Mesytec noted that all coupling components are only tested to be within +/-10%, including the pulser coupling capacitors. Thus exact testing is challenging.
The pulser inputs of our MSI-8 cards are:
MMPR-1: Pulser inputs:
Type: 2GeV Pulser : 330MeV/V
Type: 5GeV Pulser : 330MeV/V
Type: 20GeV Pulser: 1GeV/V
Thus in the attached table, we can see the 2GeV and 5GeV cards are well within tolerance, but the 20GeV card is a bit outside. Thus we should probably expect a large output range from those cards.

We also tested the MPR-16 cards. However these cards do not have a terminated pulser input, and it is not clear to us what impact that would have. In the attached table, it seems to have a pretty consistent 
factor of 4 difference though.  
Attachment 1: preamp_tests.png  15 kB  Uploaded Thu Jun 1 11:54:55 2023  | Show | Show all
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