Figure 3
RMS noise per pixel versus integration time for an incident flux of 20 X-rays pixel−1 µs−1. X-ray energy is 8.9 keV with a conversion gain of 2.75 ADU X-ray−1. The solid line is a fit to the data using σ2 = σread2 + gN, where σ is the measured noise, σread is an assumed fixed read noise per pixel, g is the conversion gain (ADU X-ray−1) and N is the number of X-rays integrated per pixel. The fixed read noise of 40 ADU that was found is much higher than the noise of 6 ADU found with zero X-ray flux. The dashed line shows the expected noise if this lower read noise floor was realised. At times above 500 µs the pixel full well is reached, causing the measured noise to deviate from Poisson behavior. |