When a gun is fired, nano to micron sized particles are deposited on the shooter and anyone close by from the vapour cloud formed by the combustion of the bullet’s primer. These particles are known as gunshot residue or GSR. For a forensic examiner wishing to solve this crime, their task therefore becomes that of finding these particles and analysing them so that they are sure that they have come from a firearm and no other source. This is where OI provides hardware and software which automates the process of finding these particles on an SEM stub, measuring their composition and imaging and measuring their morphology and reports results according to the latest version of the internationally recognised ASTM E1588 standard.
The above images show a typical EDS spectrum from a GSR particle and a typical spherical particle