2.D. Counting capabilities

The counting capability of PCDs was assessed by count rate curves (CRCs) using the baseline data with tube current values changing from 1 mA to 1,000 mA, which corresponded to the incident count rates of 4.1×10⁴–4.1×10⁷ cps/pixel or 9.6×10⁵–9.6×10⁸ cps/mm². All of the PCDs had four thresholds (N_C=4) at (20, 45, 70, and 95 keV) and a sum of the outputs of the four windows was computed. For both MEICC and 1CC, two total counts were computed, one for a sum of all of the primary counters outputs and the other for a sum of all of the coincidence counters output. The measurements were repeated 472–1,100 times for each tube current setting and the mean and the standard deviation of the total counts were computed. The default value of T_M, T₁, T_A, and T_D was 20 ns, but other values, i.e., 5, 10, 30, and 100 ns, were also used for T_M and T₁.