首页|加速电压、探测层厚度和处理方法对混合像素探测器成像的影响探究

加速电压、探测层厚度和处理方法对混合像素探测器成像的影响探究

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混合像素探测器(HPD)在低电压下的高检测效率,弥补了单片有源像素传感器(MAPS)对辐射敏感材料成像不理想的缺陷.然而,HPD的成像受限于电子计数,包括单电子信号簇的识别和事件定位等处理.其中,分簇主要受探测器的硬件和成像条件影响,但目前缺乏对这些参数和方法的系统研究.本文通过实验和蒙特卡洛模拟,分析了不同加速电压、探测层厚度和事件定位方法对MTF影响,并统计了相对能量损失.结果表明,300和500 µm探测层厚度的Timepix分别在低压和中高压时的能量损失最小.质心法在低压时定位效果与CNN方法相当;CNN在中高压的定位优势则随着电压升高而增大.Timepix在低压范围的MTF与探测层厚度成正相关;高压则反之.这对HPD相机未来在单颗粒冷冻电镜中的应用提供了参考.
A study of the effects of accelerating voltage,detector layer thickness,and processing method on imaging with hybrid pixel detectors
The high detection efficiency of hybrid pixel detectors(HPD)at low voltages compensates for the suboptimal imaging capabilities of monolithic active pixel sensors(MAPS)when applied to radiation-sensitive materials.However,HPD imaging is constrained by challenges in electron counting,such as identifying single-electron signal clusters and localizing events.Clustering,which is primarily influenced by detector hardware and imaging conditions,lacks comprehensive systematic studies.This paper examined the effects of varying accelerating voltages,detector layer thicknesses,and event localization method on the MTF through both experimental and Monte Carlo simulations approaches,and calculates the relative energy loss.The findings revealed that Timepix detectors with thicknesses of 300 µm and 500 μm exhibited the lowest relative energy loss at low and medium high voltages,respectively.The centroid localization method performed similarly to the CNN method at low voltage,but the latter's localization advantage increased with higher voltages.Additionally,for Timepix,the MTF was positively correlated with detector thickness at low voltages,whereas the relationship reversed at high voltages.These insights are valuable for the future application of HPD cameras in single particle Cryo-electron microscopy.

hybrid pixel detectorsMonte Marlo simulationevent localizationmodulation transfer functionrelative energy loss

汪进鸿、张阳、陈梅林、陈朕欣、于宏洋、金亮

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生物岛实验室(广州再生医学与健康广东省实验室),广东 广州 510005

混合像素探测器 蒙特卡洛模拟 事件定位 调制传递函数 相对能量损失

2024

电子显微学报
中国物理学会

电子显微学报

CSTPCD北大核心
影响因子:0.431
ISSN:1000-6281
年,卷(期):2024.43(6)