Optical Screen Processed Using Laser Beam for Pixel Array of High- Z Plastic Scintillator

Autor: Kishimoto, Shunji, Toda, Akehiro
Zdroj: IEEE Transactions on Nuclear Science; 2024, Vol. 71 Issue: 6 p1324-1331, 8p
Abstrakt: When a high-Z (atomic number) metal-oxide nanoparticle-loaded plastic scintillator (High-Z PLS) is mounted onto a fast pixelated photodetector, such as a silicon avalanche-photodiode array, high detection efficiency for high energy X-rays can be added to nanosecond response. To provide a spatial resolution of $\lt 100~\mu $ m, an optical screen between the pixels of the High-Z PLS is required to prevent light leakage from neighboring pixels. In this study, we attempted to form such an optical screen on a sample of 20 wt% hafnium-oxide nanoparticle-loaded PLS (Hf-PLS) using a focused laser beam. Optical transmittance of the laser-irradiated tracks was investigated. A significant decrease of 38.5% in the transmittance at 380–420 nm, which corresponds to the scintillation-light wavelength, was observed on the track. Three laser tracks with 3.2-mm pitch were formed in a 1-mm-thick sample of 20 wt% Hf-PLS with dimensions of $^{V}2.4$ mm $\times ^{H}12.3$ mm $\times ^{t}1$ mm. An SiPM array coupled with the sample was used to obtain the X-ray count distribution over the tracks using a 60-keV X-ray beam. The screen width of reducing scintillation light was measured to be 120– $250~\mu $ m [full-width at half-maximum (FWHM)] with a 30- $\mu $ m-diameter pinhole X-ray beam.
Databáze: Supplemental Index