Counting statistics of X‐ray detectors at high counting rates

Modern synchrotron radiation sources with insertion devices and focusing optics produce high fluxes of X‐rays at the sample, which leads to a requirement for photon‐counting detectors to operate at high counting rates. With high counting rates there can be significant non‐linearity in the response of the detector to incident X‐ray flux, where this non‐linearity is caused by the overlap of the electronic pulses that are produced by each X‐ray. A model that describes the overlap of detector pulses is developed in this paper. This model predicts that the correction to the counting rate for pulse overlap is the same as a conventional dead‐time correction. The model is also used to calculate the statistical uncertainty of a measurement and predicts that the error associated with a measurement can be increased significantly over that predicted by Poisson () statistics. The error differs from that predicted by a conventional dead‐time treatment.