FIG. 2.

Monte Carlo validation of theoretical formulas for noise and spectrum with pileup in Tables I and II. The graphs compare the A-vector sample covariance to the CRLB for NQ and detectors with PHA. A-vectors were computed from random measurement data as described in Sec. 2.K for three values of the dead time parameter η, 0, 0.25, and 0.5 counts per dead time, as a function of the expected number of photons incident on the detector. The individual points are the Monte Carlo values while the solid lines are the theoretical CRLB. The top panels are the A₁ and A₂ variances of the NQ detector. The bottom panels are for four bin PHA. The scales are logarithmic.