ADC
The LeCroy 2249A ADC is a charge-integrating analog-to-digital converter.
What you do is send in a GATE signal (in NIM) and while there is a GATE signal, the ADC charges 12 capacitors with each of the 12 input channels' signal. When the GATE ends, the capacitors are discharged and the time it takes to discharge is equivalent to how much charge was collected. These values are stored in registers which are read out. The register values are called "counts". This is the data we need.
GATE width = 10 - 200 ns (reliably)
GATE height <= -600 mV enables
1 count = 0.25 pC