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).