A fixed net count shows how calibration gain changes reported output. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Gain one reports the net count

Measured 12 minus dark 4 gives net 8. Gain 1 reports output 8.

18=81\cdot8=8
Detector calibrationBaseline and gain set the reported signal.measureddarknetoutput12488

Gain two doubles the calibrated output

Gain 2 maps the same net count 8 to output 16.

28=162\cdot8=16
Detector calibrationBaseline and gain set the reported signal.measureddarknetoutput124816

Gain three triples the calibrated output

Gain 3 maps net count 8 to output 24. No rail or nonlinear response is claimed in this scan.

38=243\cdot8=24
Detector calibrationBaseline and gain set the reported signal.measureddarknetoutput124824