One direct way to improve the gamma camera’s sensitivity is using large-area gamma detectors. During construction of a large-area gamma camera, achieving high uniformity (including both spatial uniformity and events count map uniformity) across the entire active area is a major challenge. Another fabrication concern is that large-scale gamma sensors (mainly with reference to scintillators) and photoelectric converters such as position-sensitive photomultiplier tubes (PSPMTs) and silicon photomultipliers (SiPMs) are required. In this work, to design a large-area gamma camera with high uniformity, a 22$\times$22 CsI(Na) array with a pitch size of 4.6$\times$4.6mm ² is divided into four optically isolated 11$\times$11 modules, where each module is coupled independently to an 8$\times$8 SiPM array (6.13$\times$6.13mm ² per channel) and is then read out using separate preamplifier electronics. The preamplified signals for each module are sampled independently via their respective analog-to-digital converters (ADCs) and the digitized signals are then processed in a single field-programmable gate array (FPGA). Extra dead zones and optical losses are avoided between the modules as a result of the optimal design used in the junction area for the four modules. This modular concept leads to a high counting rate capability. 2D flood field images of the 22$\times$22 CsI(Na) array are obtained under uniform irradiation using ²⁴¹Am. The counting rate measurements are performed using ¹³⁷Cs under various attenuation conditions. The sensitivity is tested and compared with existing devices. The results show that high uniformity (1.43) and high counting rate capability ($\sim$72% improvement) are achieved. Thanks to the large-area gamma sensor, the gamma camera developed in this paper achieves highest sensitivity among the listed devices (Locating ¹³⁷Cs producing 0.6$\pm 0.02\mathrm{\mu }$Sv/h in < 10 s). The principles developed in this paper can be applied to the construction of large-area radiation detectors.

提高伽马相机灵敏度的一种直接方法是使用大面积伽马探测器。在构造大面积伽马相机期间，要在整个活动区域实现高均匀性（包括空间均匀性和事件计数图均匀性）是一项重大挑战。另一个制造问题是需要大型伽马传感器（主要参考闪烁器）和光电转换器，例如位置敏感光电倍增管（PSPMT）和硅光电倍增管（SiPM）。在这项工作中，要设计出具有高均匀度的大面积伽玛相机，请使用22$\times$节距为4.6的22 CsI（Na）阵列$\times$4.6mm ²分为四个光电隔离的11$\times$11个模块，其中每个模块独立耦合到8个模块$\times$8 SiPM阵列（6.13$\times$每个通道6.13mm ² ），然后使用单独的前置放大器电子设备读出。每个模块的预放大信号通过其各自的模数转换器（ADC）进行独立采样，然后在单个现场可编程门阵列（FPGA）中处理数字化信号。由于在四个模块的接合区域中使用了最佳设计，因此避免了模块之间的额外死区和光学损耗。这种模块化的概念导致了高计数率功能。22的2D洪水场图像$\times$使用²⁴¹ Am在均匀辐射下获得22 CsI（Na）阵列。计数速率测量是在各种衰减条件下使用¹³⁷ Cs进行的。测试灵敏度并将其与现有设备进行比较。结果表明，高均匀度（1.43）和高计数率能力（$〜$达到72％的提升）。多亏了大面积伽马传感器，本文开发的伽马相机在列出的设备中实现了最高的灵敏度（定位¹³⁷ Cs产生0.6$\pm 0。02\mathrm{\mu }$Sv / h <10 s）。本文开发的原理可以应用于大面积辐射探测器的构造。