Automation of Gunshot-Residue Analysis by Functional Integration of a Scanning Electron Microscope and an Energy Dispersive Microanalysis System
Over the past ten years, the combination of scanning electron microscopy and energy dispersive analysis has proven to be a good and reliable tool for elemental characterization of the different components of gunshot residue. The technique evolved from a qualitative technique, involving a large amount of operator involvement, to a higher degree of quantification and automation allowing unattended analysis of gunshot residue samples. The PHAX-Scan system is geared to automated unattended analysis, particularly suited to applications such as gunshot-residue analysis.PHAX-Scan is a system based on a Philips scanning electron microscope and an EDAX PV9900 energy dispersive microanalyser in combination with highly optimised software. The system makes use of the dual processor structure of the EDAX analyser and of the bus structure of the Philips scanning electron microscopes. It is designed such that it performs a fully quantitative data reduction, including background subtraction, peak deconvolution, no-standards k-ratio determination and Z*A*F correction in typically 100 milliseconds.