Obliterated Serial Number Recovery on Materials with Laser Imprinting

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Student Presentation

Presentation Date


Faculty Sponsor

Dale Russell


Most serial numbers are imprinted by pressure induced methods; this disrupts the metal crystalline structure beneath the imprinted numbers. This damaged crystalline layer beneath the imprinted numbers is called plastic deformation and is the key to recovering the numbers after obliteration. A number of methods are available for recovering such numbers. However, laser generated characters are becoming more prevalent and this makes recovery of the numbers much more difficult because this method does not leave any known plastic deformity. There is a need in forensic science for a method to recover obliterated, laser generated serial numbers. The hypothesis of this research is that characters generated from laser treatment will leave detectable changes arising from applying heat (the laser) in an oxidizing atmosphere (air). X-ray photoelectron spectroscopy is used to analyze the sample surface for chemical compositional changes. The spectra showed that the laser treated areas had a higher concentration of oxygen than the areas not treated with the laser. Raman spectroscopy will be used to analyze the samples to detect notable changes between the laser treated and untreated areas, and it may be possible to then visually detect these changes through FTIR microscopy.

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