<title>Forensic applications of ion-beam mixing and surface spectroscopy of latent fingerprints</title>

Abstract

Ion Beam Enhancement and Detection of Latent Fingerprints Using Auger and SIMS Analysis have potential significant forensic applications. The ion implantation process is used to ion beam mix the materials of the latent fingerprints into a substrate, such that the atoms that form the latent fingerprints become an integrated part of the substrate material. The permanent record of the fingerprint can be imaged optically or with a scanning electron microscope. In addition, surface analysis techniques such as Secondary Ion Mass Spectrometry (SIMS), Particle Induced X-ray Emission (PIXE) or Auger Spectroscopy (AES) can be used to identify the chemical composition of the fingerprint material. This work involved ion beam mixing fingerprints into selected classes of substrates and used Auger spectrometry and computer aided Auger mapping to image fingerprints with low concentrations of the fingerprint materials. This combination of techniques produced images of fingerprints with heretofore-unapplied surface analysis techniques. The application of these surface analysis techniques was possible by the ion beam mixing process. Future applications are now possible with utilizing techniques more sensitive to lower concentrations of the fingerprint material. Using modern surface spectroscopy methods it can be possible to detect and map fingerprints at concentrations in parts per billion (ppb).