Fig. 9

Schematic showing the four categories in the PH distribution at energy coincidence checking. Inside the passband width indicated by W, the pulses are regarded as a true signal. However, a fraction of these come possibly from the background (category D), whereas most of them are from true signal (category A). The background pulses outside the passband (category C) are appropriately discarded as noise. The true signals outside the passband (category B) are inadvertently discarded as noise, and therefore, a correction is implemented. The correction factors were calculated using error functions, based on two half-Gaussian functions fitted separately for the higher and lower sides of the PH distribution