[B._Beckhoff,_et_al.]_Handbook_of_Practical_X-Ray_(b-ok.org).pdf

Since the introduction of scanning electron

Info icon This preview shows pages 747–749. Sign up to view the full content.

Since the introduction of scanning electron microscopy/energy dispersive X-ray examination of gunshot residue in the 1970s, it has been considered that the firing of a gun produces materials that are unique to that process. Wolten [718], in the most comprehensive study of GSR analysis by SEM, stated that micron-sized particles, having a morphology consistent with rapid cooling, formed a liquid state. They contained the elemental combustion of either lead/barium/antimony or barium/antimony and were unique to the detonation of the primer of a round of ammunition. Metallic particle classification was carried out in the following way: the most characteristic (unique) particles were singled out, followed by indica- tive, one and two component particles, e.g. antimony, lead, lead/antimony, always accompanying the former and occurring in considerably greater quan- tities. [721]. Finding GSR on material received from a suspect confirms his or her participation in the event. Only a few experienced specialists undertake the difficult task of identify- ing used ammunition on the basis of qualitative assessment of differences in the chemical composition of GSR [712]. Recently, some attempts were made at a systematic study of primer discharge residue originating from various brands of ammunition. Evaluation of the obtained analytical results was car- ried out by, among other things, chemometric methods [708, 709]. These stud- ies showed significant differences between gunshot residues originating from
Image of page 747

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Methodological Developments and Applications 727 ammunition types, and thus it was possible to achieve at least group identifi- cation of ammunition (and hence the type of firearm used) from information on GSR alone. In order to elaborate a reliable scheme of individual classifica- tion of ammunition on the basis of GSR alone, it cannot be excluded that it will be necessary to analyse the internal structure and chemical composition of individual particles [714]. The XRF method, however, is irreplaceable in investigations of gunshot holes occurring on various bases. A fragment of fabric cut from clothing or a fragment of skin or bones together with the gunshot wound can be placed directly in the measuring-dish of the X-ray spectrometer and analysed for the presence of metals originating from the primer, the bullet and the cartridge. Their disclosure confirms the use of a firearm and contributes to inferences about estimations of the shooting distance [716]. Recently, the first attempt to use µ -XRF in examinations of gunshot residues was carried out [710]. Charpentier et al. applied this method to the analysis of gunshot residues from primers of lead-free ammunition and ammu- nition in the area surrounding bullet holes, and found it to be a very important tool for determining shooting distance. They determined the elemental com- position of a 500- µ m zone near the bullet hole. In addition, as the method has a mapping system, it provided data on elemental distribution in a given area.
Image of page 748
Image of page 749
This is the end of the preview. Sign up to access the rest of the document.
  • Spring '14
  • MichaelDudley

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern