Precise Measurement of Rising Edge in Fast Luminescent Scintillators and Its Application in Ultrafast Photodetection

doi:10.16553/j.cnki.issn1000-985x.2025.0201

Abstract

Abstract: As a key material for converting high-energy radiation into optical signals，the rise time of scintillators directly affects the time resolution of detection systems. This parameter is crucial for cutting-edge applications such as pulse diagnostics and beam monitoring in X-ray free-electron laser （XFEL） facilities，as well as time-of-flight positron emission tomography （TOF-PET）. This work thoroughly explores the significance of the rise time，a core temporal performance parameter of scintillators，highlights the limitations of existing measurement techniques，and proposes an innovative high-precision measurement scheme. The study utilizes a 355 nm picosecond pulsed laser，splitting the beam into trigger and excitation paths，coupled with a spectrometer for monochromatic light selection. This approach effectively overcomes challenges such as laser pulse jitter and weak fluorescence signal acquisition. Experimental results show that，the traditional LYSO∶Ce scintillator has a rise time of （273.7±26.9） ps，while the emerging all-inorganic perovskite scintillator CsPbCl₃ exhibits an ultrafast rise time as low as （209.6±6.7） ps and a decay time of only （663.4±34.2） ps. This sub-hundred-picosecond rise time and ultrafast response characteristic highlight the great potential of CsPbCl₃ in the field of gigahertz high-repetition-rate ultrafast detectors. It provides critical technical support for bunch-by-bunch diagnostics in synchrotron radiation and free-electron laser facilities，while also offering key methodologies and physical data for the screening and optimization of next-generation ultrafast scintillators.

Key words: perovskite scintillator; CsPbCl₃; rise time; high-repetition-rate; X-ray detector; gigahertz

CLC Number:

O799

CHEN Zhenhua, LU Yanyu, GUO Zhi, LIU Haigang, ZHANG Xiangzhi, ZOU Ying, WANG Yong, TAI Renzhong, DING Dongzhou, YANG Fan. Precise Measurement of Rising Edge in Fast Luminescent Scintillators and Its Application in Ultrafast Photodetection[J]. Journal of Synthetic Crystals, 2026, 55(2): 182-190.

Figures/Tables 6

Fig.1 Schematic diagram of defect energy level structure and carrier relaxation pathways in CsPbCl3

Fig.2 Schematic diagram and test results of a high-precision TCSPC rising edge measurement system. （a） Principle and optical path design of TCSPC system （M1-M2 are mirrors，Beam splitter is a beam splitter，Fast photodiode is a trigger photodiode）；（b） IRF measured by experimental system at 420 nm；（c） FWHM of Gaussian-fitted IRF is 0.15 ns. The test was conducted using a 355 nm laser with an intensity of 50 mW

Fig.3 Characterization of morphology and optical properties of CsPbCl3 single crystals. （a） SEM image of a CsPbCl3 single crystal，with an optical photograph of actual crystal shown in inset in upper right corner；（b） defect density optimized by temperature gradient method，with Laue diffraction pattern confirming a pure perovskite phase；（c） photoluminescence （PL） spectrum of CsPbCl3 single crystal excited by a 355 nm laser，with a scanning step size of 1 nm

Fig.4 TCSPC test results of LYSO and CsPbCl3 single crystals. （a） TCSPC measurement results of LYSO∶Ce at 420 nm，with excitation light at 355 nm；（b） TCSPC measurement results of CsPbCl3 single crystals at 420 nm，all measurements were performed at six different positions on the same sample

Table 1 Rise time and decay time measured values

Measurement times	Rise time/ns		Decay time/ns
Measurement times	CsPbCl₃	LYSO	CsPbCl₃	LYSO
1	0.207 8	0.245 2	0.606 1	41.903 8
2	0.213 4	0.307 6	0.722 7	43.340 8
3	0.214 7	0.283 5	0.654 0	43.815 0
4	0.213 1	0.255 3	0.660 7	40.100 0
5	0.195 4	0.306 4	0.662 0	36.890 0
6	0.213 0	0.244 3	0.674 7	44.745 0
Average value	0.209 6	0.273 7	0.663 4	41.799 1
Standard deviation	0.006 7	0.026 9	0.034 2	2.649 4
Deviation/%	3.20	9.81	5.16	6.34

Fig.5 Free-electron laser beam loss diagnostic setup and test results. （a） Diagram of free-electron laser beam loss diagnostic device；（b） response of scintillator to single pulses from the free-electron laser in beam loss diagnostics，with an XFEL energy of 600 eV and a repetition rate of 10 Hz；（c） oscilloscope image of a CsPbCl3 single crystal excited by a picosecond pulsed laser，with a pulse interval of 0.95 ns

References 23

[1]	郑嘉茜，陈俊锋，李翔，等. 掺杂抑制氟化钡晶体慢闪烁成分研究进展［J］. 人工晶体学报，2022，51（6）：951-964.
	ZHENG J Q，CHEN J F，LI X，et al. Research progress on suppression of slow scintillation component in barium fluoride crystal by doping［J］. Journal of Synthetic Crystals，2022，51（6）：951-964 （in Chinese）.
[2]	CHEN Q S，WU J，OU X Y，et al. All-inorganic perovskite nanocrystal scintillators［J］. Nature，2018，561（7721）：88-93.
[3]	GAFFNEY K J，CHAPMAN H N. Imaging atomic structure and dynamics with ultrafast X-ray scattering［J］. Science，2007，316（5830）：1444-1448.
[4]	GAO R L，OUYANG X，WANG Q，et al. High-performance radioluminescent nuclear battery based on ultrabright Cs₃Cu₂I₅：Tl single crystal scintillator［J］. IEEE Transactions on Nuclear Science，2024，71（12）：2530-2535.
[5]	KHAKHULIN D，OTTE F，BIEDNOV M，et al. Ultrafast X-ray photochemistry at European XFEL：capabilities of the femtosecond X-ray experiments （FXE） instrument［J］. Applied Sciences，2020，10（3）：995.
[6]	KOBAYASHI M，OMATA K，SUGIMOTO S，et al. Scintillation characteristics of CsPbCl₃ single crystals［J］. Nuclear Instruments and Methods in Physics Research Section A：Accelerators，Spectrometers，Detectors and Associated Equipment，2008，592（3）：369-373.
[7]	MADDALENA F，TJAHJANA L，XIE A Z，et al. Inorganic，organic，and perovskite halides with nanotechnology for high-light yield X- and γ-ray scintillators［J］. Crystals，2019，9（2）：88.
[8]	MORADI F，BRADLEY D A，TARIF Z H，et al. Time-resolved optical fiber measurements：a review of scintillator materials and applications［J］. Radiation Detection Technology and Methods，2025，9（1）：1-16.
[9]	MYKHAYLYK V B，RUDKO M，KRAUS H，et al. Ultra-fast low temperature scintillation and X-ray luminescence of CsPbCl₃ crystals［J］. Journal of Materials Chemistry C，2023，11（2）：656-665.
[10]	REN G H，WU Y T. On the doping effects and structural defects in some classical inorganic scintillation crystals［J］. Acta Mineralogica Sinica，2024，44（5）：689-701.
[11]	SINGH R，SINGH A，KUMAR S，et al. Ultrafast dynamics of self-trapped excitons in Cs₂AgInCl₆∶Al³⁺ double perovskite nanocrystals［J］. Nano Letters，2024，24（22）：6797-6804.
[12]	SOBOLEV E，ZOLOTAREV S，GIEWEKEMEYER K，et al. Megahertz single-particle imaging at the European XFEL［J］. Communications Physics，2020，3：97.
[13]	WAHL M. Modern TCSPC electronics：principles and acquisition modes［M］//KAPUSTA P，WAHL M，ERDMANN R. Advanced photon counting：applications，methods，instrumentation. Cham：Springer International Publishing，2015：1-21.
[14]	YAN X L，PENG C，HE W M，et al. Radiation induced light output enhancement of CsPbCl₃ crystal［J］. Journal of Luminescence，2025，281：121162.
[15]	ZHANG F，OUYANG X，PENG X，et al. Selective enhancement of deep ultraviolet luminescence in barium fluoride scintillators via photonic crystal structures［J］. Applied Physics Letters，2024，125（14）：143503.
[16]	ZHANG Y L，SHEN M，CHENG B L，et al. Ultrafast scintillation at room temperature achieved in CsPbCl₃-based single crystals through Br over-doping［J］. Journal of Materials Chemistry C，2024，12（20）：7169-7175.
[17]	ZHAO X Y，ZHANG Z Y，CHEN Z H，et al. High repetition single-pulse photodetector based on CsF single crystals with controllable decay time［J］. Next Materials，2025，8：100675.
[18]	ZHU M Q，WEN W W，WANG L，et al. Research progress of perovskite scintillation crystals［J］. Journal of Synthetic Crystals，2021，50（10）：1844-1857.
[19]	CHEN J，LV J，LIU X L，et al. A study on theoretical models for investigating time-resolved photoluminescence in halide perovskites［J］. Physical Chemistry Chemical Physics，2023，25（11）：7574-7588.
[20]	李雯，李云云，迟晓慧，等. X射线成像用零维无铅杂化卤化物闪烁体研究进展（特邀）［J］. 激光与光电子学进展，2024，61（3）：0334001.
	LI W，LI Y Y，CHI X H，et al. Research progresses of zero-dimensional lead-free hybrid halides scintillators for X-ray imaging （Invited）［J］. Laser & Optoelectronics Progress，2024，61（3）：0334001 （in Chinese）.
[21]	YU J F，FAN Y H，LI X Y，et al. Recent progress of zero-dimensional hybrid antimony-based metal halide materials in X-ray detection［J］. Chinese Journal of Luminescence，2025，46（7）：1221-1231.
[22]	ZHANG Q K，WANG，ZHANG C F. Self-trapped excitons in metal halide perovskite semiconductors［J］. Progress in Physics，2023，43（6）：161-177.
[23]	左晓艺，武彤，王绍涵，等. 超快闪烁晶体Cs₂ZnCl₄研究进展［J］. 发光学报，2025，46（5）：863-872.
	ZUO X Y，WU T，WANG S H，et al. Research progress of Cs₂ZnCl₄ ultrafast scintillation crystals［J］. Chinese Journal of Luminescence，2025，46（5）：863-872 （in Chinese）.