We report the development of a gamma-ray imaging device, named Large-Area Hybrid Gamma Imager (LAHGI), featuring high imaging sensitivity and good imaging resolution over a broad energy range. A hybrid collimation method, which combines mechanical and electronic collimation, is employed for a stable imaging performance based on large-area scintillation detectors for high imaging sensitivity. The system comprises two monolithic position-sensitive NaI(Tl) scintillation detectors with a crystal area of 27 × 27 cm² and a tungsten coded aperture mask with a modified uniformly redundant array (MURA) pattern. The performance of the system was evaluated under several source conditions. The system showed good imaging resolution (i.e., 6.0–8.9° FWHM) for the entire energy range of 59.5–1330 keV considered in the present study. It also showed very high imaging sensitivity, successfully imaging a 253 μCi ¹³⁷Cs source located 15 m away in 1 min; this performance is notable considering that the dose rate at the front surface of the system, due to the existence of the ¹³⁷Cs source, was only 0.003 μSv/h, which corresponds to ∼3% of the background level.

我们报告了一种名为大面积混合伽马成像仪 (LAHGI) 的伽马射线成像设备的开发，该设备在宽能量范围内具有高成像灵敏度和良好的成像分辨率。采用机械准直和电子准直相结合的混合准直方法，基于大面积闪烁探测器的高成像灵敏度，获得稳定的成像性能。该系统包括两个单片位置敏感的 NaI(Tl) 闪烁探测器，晶体面积为 27 × 27 cm ²和钨编码孔径掩模，具有改进的均匀冗余阵列 (MURA) 图案。在几种源条件下评估了系统的性能。对于本研究中考虑的 59.5-1330 keV 的整个能量范围，该系统显示出良好的成像分辨率（即 6.0-8.9° FWHM）。它还显示出非常高的成像灵敏度，在 1 分钟内成功成像了位于 15 m 外的 253 μCi ¹³⁷ Cs 源；考虑到由于¹³⁷ Cs 源的存在，系统前表面的剂量率仅为0.003 μSv/h，相当于本底水平的 3%，因此该性能值得注意。