High repetition single-pulse photodetector based on CsF single crystals with controllable decay time

The development of stable inorganic scintillators holds great potential for advancing high-speed detection and imaging technologies. The primary challenge is achieving nanosecond-scale or even sub-nanosecond-scale decay time and effectively coupling these scintillators with ultrafast electronics with a high signal-to-noise ratio. Herein, we report a critical inorganic scintillator crystal material, a CsF single crystal with a fluorite-type structure showing controllable nanosecond-scale decay, which proves to be an excellent ultrafast single-pulse photodetector. We first used synchrotron-based resonant X-ray emission spectroscopy (RXES) to show that shallow energy level defects are the source of fast luminescence in the radiation process of CsF materials, providing a basis for optimizing preparation conditions and regulating the luminescence decay lifetime. The custom-developed electronics use SerDes technology to achieve GHz level high repetition rate narrow pulse acquisition and counting processing, enabling a fast response, low noise, and rapid output, thus overcoming the challenge of matching fast-decaying scintillators with ultrafast electronics. When a CsF single crystal is excited by a picosecond ultraviolet pulsed light source and coupled with a high-sensitivity photomultiplier tube (PMT) photoelectric detection device, single pulses with a 467 MHz bandwidth and 2.4 ns intervals can be clearly distinguished, corresponding to high repetition rates over 400 MHz. Compared with commercial Ce:YAG scintillation crystals, the maximum mass-resolved repetition frequency based on fast-decay CsF is increased by more than 90 times. • Custom developed high repetition and low-noise fast electronics successfully coupled with fast decay CsF single crystals. • Ultrafast CsF single-pulse photodetector with > 400 MHz high repetition rates was demonstrated. • CsF photodetector demonstrate 90 times higher repetition frequency higher than commercial Cs:YAG scintillation.