Impact-disrupted gunshot residue：A sub-micron analysis using a novel collection protocol

作     者：V.Spathis 

作者机构：School of Physical Sciences University of Kent 

出 版 物：《Defence Technology（防务技术）》 (Defence Technology)

年 卷 期：2017年第13卷第3期

页      面：143-149页

核心收录：

学科分类：1001[医学-基础医学(可授医学、理学学位)] 08[工学] 082603[工学-火炮、自动武器与弹药工程] 0826[工学-兵器科学与技术] 0838[工学-公安技术] 100105[医学-法医学] 10[医学] 

主　　题：亚微米级 残留物 收集 球形颗粒 结构形态 协议 撞击 元素组成 

摘      要：The analysis of gunshot residue(GSR) has played an integral role within the legal system in relation to shooting cases. With a characteristic elemental composition of lead, antimony, barium, and a typically discriminative spheroidal morphology, the presence and distribution of GSR can aid in firearm investigations. In this experiment, three shots of low velocity rim-fire ammunition were fired over polished silicon collection substrates placed at six intervals over a 100 cm range. The samples were analysed using a Field Emission Gun Scanning Electron Microscope(FEG-SEM) in conjunction with an X-flash Energy Dispersive X-ray(EDX) detector, allowing for GSR particle analyses of composition and structure at the sub-micron level. The results of this experiment indicate that although classic spheroidal particles are present consistently throughout the entire range of samples their sizes vary significantly, and at certain distances from the firearm particles with an irregular morphology were discerned, forming impactdisrupted GSR particles, henceforth colloquially referred to as splats. Upon further analysis, trends with regards to the formation of these splat particles were distinguished. An increase in splat frequency was observed starting at 10 cm from the firearm, with 147 mm^(-2) splat density, reaching a maximal flux at 40 cm(451 mm^(-2)), followed by a gradual decrease to the maximum range sampled. Moreover, the structural morphology of the splats changes throughout the sampling range. At the distances closest to the firearm, molten-looking particles were formed, demonstrating the metallic residues were in a liquid state when their flight path was disrupted. However, at increased distances-primarily where the discharge plume was at maximum dispersion and moving away from the firearm, the residues have had time to cool in-fight resulting in semi-congealed and solid particles that subsequently disrupted upon impact, forming more structured as well as disaggregated