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在SEM/EDS自动发现iGSR粒子中的假负概率:贝叶斯式方法

Martín A Onetto^1,2,3, Edgardo Carignano⁴, Rodolfo G Pregliasco^1,3

¹Sección Física Forense, Centro Atómico Bariloche/Comisión Nacional de Energía Atómica (CNEA), San Carlos de Bariloche, Argentina.

Journal of forensic sciences

|July 12, 2023

概括

优化扫描电子显微镜 (SEM/EDS) 的分辨率是检测无机火药残留物 (iGSR) 的关键. 较低的像素大小显著降低了错过关键iGSR粒子的机会,提高了法医分析的效率.

科学领域:

法医科学法医科学法医科学
材料科学材料科学材料科学
分析化学分析化学

背景情况:

自动扫描电子显微镜与能量分散式X射线光谱学 (SEM/EDS) 是无机火药残留物 (iGSR) 检测的标准.
粒子检测受收集,保存,污染和分析方法的影响.
设备的分辨率,特别是像素大小,极大地影响了iGSR粒子的检测能力.

研究的目的:

调查SEM/EDS设备分辨率对iGSR粒子检测的影响.
根据图像像素分辨率量化缺失iGSR粒子的概率.
开发和验证一个模型,将粒子大小,设备设置和检测概率联系起来.

主要方法:

以SEM/EDS图像像像素分辨率计算iGSR颗粒缺失的概率.
开发并验证了一个模型,将颗粒大小与iGSR检测设备参数相关联.
将验证的模型应用于320个法医科学实验室样本.

主要成果:

缺失所有特征性iGSR粒子的概率在0.32μm2.2以下的像素大小下为5%以下.
较大的像素大小,高达常见实验室标准 (0.16μm2) 的两倍,对于初始样本扫描仍然有效.
优化的像素分辨率提高了特征iGSR粒子的检测率.

结论:

SEM/EDS像素分辨率是可靠的iGSR检测的一个关键参数.
使用0.32μm2或更小的像素大小,可以最大限度地降低缺失特性iGSR粒子的风险.
调整分辨率设置可以显著减少实验室的工作量,同时保持法医分析的高检测率.

关键词:

贝叶斯统计学贝叶斯统计学这是GSR的GSR.枪支残留物枪支残留物最佳配置的最佳配置.颗粒探测器可以检测到颗粒.检测的概率检测的概率.尺寸分布的大小分布.

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