Figure 3.

Zero-frequency DQE, taking into account the detector cascade and pixel noise. The family of curves shown gives the DQE for the simulated detector as derived by equation (14) for regions of interest consisting of 6 × 6, 10 × 10, 14 × 14 and 18 × 18 pixels. For relatively weak signals of less than 1 × 10⁴ X-ray photons, the size of the region of interest becomes important owing to the pixel-noise component of the DQE expression. At high flux, the DQE is limited by the phosphor quantum absorption and the response of the cascade chain.