Threshold scan is performed for injected charges of 0.5, 1.0 and 1.5fC. In each ase, a complementary error function is fitted to the data. For each injected charge, the threshold at which occupancy is 50% corresponds to the median of the injected charge distribution. The front-end gain is calculated from a linear fit to the fit results for the three scans. The output noise from the scan taken with 1.0fC injected charge is divided by the gain to determine the input noise (in fC or ENC). Also known as
3PG.