The false beat signal of a high-speed X-ray imaging detector for synchrotron radiation experiments and its elimination with a synchronized CITIUS detector

Recent advances in high-speed X-ray imaging detectors for synchrotron radiation experiments have enabled frame rates to exceed 10 kframes/s. The frame rates are getting closer to the revolution frequencies of the large-scale storage rings, which are of the order of 100 kHz. In such cases, a false asynchronous-operation-induced beat (FAB) may be overlapped with the true signal. In order to eliminate FAB, we have developed a clock and trigger distributor to make the detector operate with frames cycles matching multiples of the revolution of the electron bunches in the storage rings. To experimentally demonstrate the effect, we have conducted a nuclear resonant scattering experiment with the CITIUS detector operating at 17.4 kframes/s. The measured spectra showed a signal-to-noise ratio identical to the Poisson statistics, indicating that the successful elimination of FAB by synchronization. To quantitatively assess the magnitude of FAB, numerical simulations have been carried out. FABs show peak-to-peak intensity variations ranging from 0.04 to 7.5% for SPring-8 bunch patterns. The dependence of the effective frame rates and bunch-filling modes on FABs are also quantitatively reported.