Source: International Atomic Energy Agency – IAEA
Ion beam analysis (IBA) is another nuclear method gaining ground in criminal investigations. For this kind of analysis, ion beam accelerators are used to speed up ions or electrons, producing a beam of charged particles. When samples of forensic evidence are placed into the ion beam, they emit radiation which can be picked up and analysed. Using ions enables investigators to understand the composition and origin of the sample, which can help to analyse drugs, explosive and gunshot residues, fake historical artifacts or art. Determining the age and composition of samples means they can be more effectively used as evidence in investigations.
Gunshot residues, for example, can help to investigate violent crimes involving firearms. A gunshot residue is a cloud of vapours and particles released from the explosion of a cartridge in a firearm. Nuclear techniques, such as ion beam analysis, help to detect the inorganic components originating from the shot to detect tiny particles on items related to a shooting (e.g. on the suspect’s hands or clothes) in order to confirm the identity of the shooter.
IBA enables investigators to conduct elemental mapping, which helps in the analysis of specific parts of the evidence and detects tiny traces of incriminating substances, such as microscopic particles of residues on particularly small parts of clothing.
Ion beams have also been used to analyse glass shards from hit and run accidents, which could prove useful in investigations of crimes involving vehicles. Studies show that through a combination of IBA and machine learning, glass fragments from car windows can be traced back to various car models and manufacturers with up to 80 per cent accuracy.