Speaker
Description
Alpha particles imaging with zero-dimensional halide perovskite scintillator
Chihaya Fujiwara1,2*, Yusuke Urano3, Akihiro Yamaji4, Akira Yoshiakwa1,2 and Shunsuke Kurosawa4,5
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Sendai, Miyagi, 980-5877, Japan
- Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11 Aoba, Aramaki, Aoba-ku, Miyagi, 980-8579, Japan
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2, Asashiro-Nishi, Kumatori, Osaka, 590-0494, Japan
- Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
- Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Corresponding author, fujiwara.chihaya.p@dc.tohoku.ac.jp
Real-time imaging of alpha-emitting radioactive dust is strongly required in decommissioning environments such as the Fukushima Daiichi Nuclear Power Plant in order to prevent internal exposure of workers. So far, detector systems combining scintillators with complementary metal–oxide–semiconductor (CMOS) image sensors have been developed [1,2]. However, conventional scintillators such as Ag:ZnS typically exhibit emission wavelengths around 400 nm, which do not match well with the peak quantum efficiency of CMOS sensors in the 500–700 nm range. This spectral mismatch significantly limits the detection efficiency and spatial resolution of alpha particle imaging. To achieve high-resolution imaging, it is essential not only to use scintillators with high light yield but also to tailor their emission wavelength to match the sensitivity range of CMOS sensors. Recently, zero-dimensional halide perovskite materials have emerged as promising scintillators due to their high light-output and tunable emission properties. Notably, their emission wavelength can be widely controlled from the blue to near-infrared region through compositional engineering. In this study, we focus on Cs2ZrCl6, a zero-dimensional halide material with high atmospheric stability, and investigate emission wavelength tuning via partial substitution of chlorine with iodine for alpha particles imaging applications.
Cs2ZrCl6 and iodine-substituted Cs2Zr(Cl,I)6 were synthesized by a melt-solidification at temperatures above 850°C. The obtained materials were ground into powders and mixed with an optical resin to fabricate composite scintillator imaging plates.
As shown in Fig.1 (a), under ultraviolet excitation, the Cs2Zr(Cl,I)6 composite plate exhibited intense yellow-to-orange emission, which was well matched to the high-sensitivity region of Si-based CMOS sensors. Using the fabricated imaging plate, clear visualization of alpha particle emitted from a ²⁴¹Am source was successfully demonstrated with high contrast as shown in Fig.1 (b). These results indicated that iodine-substituted Cs2ZrCl6 was a promising candidate for high-sensitivity and high-resolution alpha particle imaging.
[1] Y. Urano et al., J. Instrum., vol. 18, no. 12, p. C12009, Dec. 2023.
[2] S. Kurosawa, et al.,” J. Instrum., vol. 9, no. 07, pp. C07015–C07015, July 2014.