Nanosecond scintillator decay time measurement using a pulsed X-ray source

Traditional methods for measuring the decay time of scintillators typically rely on radioactive source excitation (e.g., 137Cs, 241Am). However, this approach faces three key challenges: (1) stochastic timing of radiation pulse emissions due to the Poisson nature of radioactive decay, complicating precise determination of temporal initiation points; (2) low photon emission rates from conventional sources, which limit the characterization of scintillator response dynamics under high-repetition-rate conditions; and (3) inherent radiation safety concerns associated with radioactive isotopes. A nanosecond pulsed X-ray source with high-repetition-rate capability (12.5 MHz, 4 ns FWHM pulse width) was developed. By implementing synchronized trigger electronics, precise control of event initiation timing was achieved, enabling precision measurements of scintillator fluorescence lifetimes. Experimental results shows that the system can rapidly and accurately measure decay times over 20 ns. Specifically, the fast decay components of LYSO: Ce and YAP: Ce scintillators were determined to be 42.3 ns and 27.8 ns, respectively, with deviations of less than 1.5% compared to literature values (42 ns, 28 ns). The results indicate that this newly developed pulsed X-ray source is an effective and efficient tool for accurate scintillator decay time measurement, providing significant improvements in scintillator testing.