Figure 2
Response of the NaI detector in the three operating modes of the APS. The count rate of the ion chamber is scaled to that of the scintillator in the low-count-rate regime, and as such is treated as the `true' count rate of the scintillator. For each operating mode, models of non-extended dead-time (dotted lines) and extended dead-time (solid lines) are shown. The dashed line for hybrid singlet mode is the model of Lee & Mills (1992), as explained in the text. |