Fig. 4

Intrinsic count rate performance in air. Measured results are shown with red solid carets and simulated results with black empty carets. Additional lines illustrate the maximum OCR and 20% loss OCR for measurement (solid lines) and simulation (dashed lines). The count rates are in agreement below the maximum OCR, while above the maximum, the measured OCR falls off the trend line as the photopeak shifted to lower energies