Dipartimento di Scienze Anatomiche, Istologiche, Medico-Legali e dell'Apparato Locomotore, SAPIENZA Università di Roma, Italy.
Forensic Sci Int. 2013 Sep 10;231(1-3):219-28. doi: 10.1016/j.forsciint.2013.05.006. Epub 2013 Jun 20.
Gunshot Residue (GSR) is residual material from the discharge of a firearm, which frequently provides crucial information in criminal investigations. Changes in ammunition manufacturing are gradually phasing out the heavy metals on which current forensic GSR analysis is based, and the latest Heavy Metal Free (HMF) primers urgently demand new forensic solutions. Proton scanning microbeam Ion Beam Analysis (IBA), in conjunction with the Scanning Electron Microscope equipped with an Energy Dispersive X-ray Spectrometer (SEM-EDS), can be introduced into forensic analysis to solve both new and old problems, with a procedure entirely commensurate with current forensic practice. Six cartridges producing GSR particles known to be interesting in casework by both experience and the literature were selected for this study. A standard procedure to relocate the same particles previously analysed by SEM-EDS, based on both secondary electron (SE) and X-ray imaging was developed and tested. Elemental Particle Induced X-ray Emission (PIXE) mapping of the emitted X-rays allowed relocation in a scan of 10 μm × 10 μm of even a 1 μm GSR particle. The comparison between spectra from the same particle obtained by SEM-EDS and IBA-PIXE showed that the latter is much more sensitive at mid-high energies. Results that are very interesting in a forensic context were obtained with particles from a cartridge containing mercury fulminate in the primer. Particle-induced gamma-ray emission (PIGE) maps of a particles from HMF cartridges allowed identification of Boron and Sodium in particles from hands using the (10)B(p,α1γ)(7)Be, (11)B(p,p1γ)(11)B and (23)Na(p,p1γ)(23)Na reactions, which is extraordinary in a forensic context. The capability for quantitative analysis of elements within individual particles by IBA was also demonstrated, giving the opportunity to begin a new chapter in the research on GSR particles. The integrated procedure that was developed, which makes use of all the IBA signals, has unprecedented characterisation and discrimination power for GSR samples.
射击残留物（GSR）是枪支发射后的残留物质，经常为刑事调查提供关键信息。弹药制造的变化正在逐步淘汰当前法医 GSR 分析所依据的重金属，而最新的无重金属（HMF）引发剂迫切需要新的法医解决方案。质子扫描微束离子束分析（IBA）与配备能量色散 X 射线光谱仪（SEM-EDS）的扫描电子显微镜结合使用，可以引入法医分析中，以解决新的和旧的问题，其程序完全与当前的法医实践相符。本研究选择了六个产生 GSR 颗粒的弹药，这些颗粒已知在经验和文献方面都对案件分析很感兴趣。开发并测试了一种基于二次电子（SE）和 X 射线成像重新定位先前由 SEM-EDS 分析的相同颗粒的标准程序。发射 X 射线的元素粒子诱发 X 射线发射（PIXE）图谱允许在 10μm×10μm 的扫描中重新定位甚至 1μm 的 GSR 颗粒。通过 SEM-EDS 和 IBA-PIXE 获得的同一颗粒的光谱比较表明，后者在中高能时更灵敏。从含有汞爆炸物的底火的弹药中获得的颗粒的结果非常有趣。HMF 弹药颗粒的粒子诱导伽马射线发射（PIGE）图谱允许使用（10）B（p，α1γ）（7）Be、（11）B（p，p1γ）（11）B 和（23）Na（p，p1γ）（23）Na 反应识别来自手部的颗粒中的硼和钠，这在法医背景下是非常特别的。通过 IBA 对单个颗粒内元素进行定量分析的能力也得到了证明，为 GSR 颗粒的研究开辟了新的篇章。开发的综合程序利用了所有 IBA 信号，对 GSR 样品具有前所未有的表征和区分能力。
