Fig. 2.

Relative CRLB of the variances for different pulse-detection logics, assuming ideal energy response. The $x$-axis corresponds to the incident flux normalized by the characteristic count rate, but the variances are reported at constant dose, so the measurement time decreases as the incident flux is increased. Within each plot, the CRLB has been normalized to performance at very low count rates. Hence, both axes are unitless. Error bars represent 95% confidence intervals. (a) Water material. (b) Equivalent monoenergetic imaging.