ADC Counts versus Time

Low gain
adc1 | adc3 | adc5 | adc7
High gain
adc2 | adc4 | adc6 | adc8

Figure 1 : ADC counts versus time. The low gain tubes get lower data because their voltages are lower. Lower voltage equals less electrons produced per incident photon.
There is a shift between like tubes because the pedestals are different. The pedestals give the minimum data value. The maximum data value (~1129) comes from the limits of the ADC. The registers are 10-bit which should give a max of 1024, but I have been using bit 11, the overflow bit, for valid data. Why it stops at 1129 and not 2048 is probably due to the limits of the capacitors (or the PMT).