CCD与CMOS像素传感器γ射线电离辐射响应特性对比研究

Comparative Study on γ-ray Radiation Response Characteristics of CCD and CMOS Pixel Sensor

为了研究CCD与CMOS像素传感器对γ射线电离辐射的响应差异,对比研究了4类像素传感器的结构特点和辐射响应特性。通过辐射实验,对各传感器在不同辐射水平条件下的光子响应事件分布、平均灰度值以及典型光子响应事件进行研究。研究结果表明:光子响应程度均与辐射剂量率相关;CCD像素传感器的沟道传输方式使每列像元间的辐射响应更容易相互干扰;平均灰度值随剂量率的增大存在明显的梯度,各积分周期内输出信号灰度值围绕均值上下波动,CCD像素传感器输出信号灰度浮动范围较小;CMOS像素传感器各像元对光子的响应更加明显,CCD像素传感器各像元的响应信号易与相邻像元发生串扰;各类像素传感器典型辐射响应事件区域中发生光子响应的像元数量随剂量率的增大而增多,响应事件并非单个光子的行为,而是反映了多个光子在区域内同时沉积能量的过程。本研究为开发像素传感器的γ射线辐射探测技术和应用提供了重要的理论分析和实验数据支撑。

Study on ionizing radiation response characteristics of four types of CCD and CMOS pixel image sensors were presented. The photon response event distribution,average pixel value and typical photon radiation response events of sensors were analyzed by comparing the structural characteristics of various pixel sensors at different dose rates. The reasons for the ionizing radiation response difference were further discussed. The experimental results show that the degree of photon response is related to the radiation dose rate. The channel transmission mode of CCD pixel sensor makes the radiation response of each pixel easier to interfere with each other. The average pixel value has obvious gradient with the different dose rates. The output signal fluctuates around the mean pixel value,and the fluctuation range of CCD pixel sensors are smaller. The response of each pixel of CMOS pixel sensor to photon is more obvious. The signal produced by the majority of pixels to the photon is drowned by the crosstalk signals caused by the neighboring pixels in CCD pixel sensors. The number of pixels corresponding to photon response in the typical radiation response region of each pixelsensor increases with large dose rate,which indicates that the response event is not the behavior of any single photon,but reflects the process of simultaneous deposition of energy by multiple photons in the region.