Monte Carlo simulation of dead time in fluorescence detectors and its dependence on beam structure

Monte Carlo (MC) simulation study of the dependence of paralyzable dead time value on the bunch filling pattern of the beam at Diamond Light Source (DLS) synchrotron and its validation using experimental data is reported. There are two major beam structures in DLS namely, Standard mode and Hybrid mode. A difference in experimental values of dead time for 64-pixel germanium detector for standard mode and hybrid mode was found which triggered this study. For each ICR, the simulation outputs the corresponding Output Count Rate (OCR) and time stamp of the output photon. Pile-up correction has been implemented in the code to reject the pile-up photons. MC simulations are within 4.5% error from the experimental data depending on the beam structure. The simulation has been validated with 36-pixel germanium detector data collected with the beam and portable X-ray set as also with 64-pixel germanium and Silicon Drift Detector (SDD) data collected with beam.