Page 33 - Veritas - 02.03.22

The University of Nottingham has worked in every aspect to develop a

method to obtain high-resolution fingerprint images from curved or chal-

lenging surfaces.

James Sharp, an associate professor in the school of physics and

astronomy, and his team developed a technique based on spectrometry

known as the time-of-flight secondary ion mass spectrometry along with

a significant creation of a rotation stage, which actually helps us to study

the fingerprint deposited on curved objects bullet, metal casings, and oth-

er surfaces.

The ToF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry) is a

technique in which high energy beams of positive ions are made incident

on the sample surface to free secondary ions from the surface as they col-

lide with any material. The ions are then accelerated on the ToF analyzer.

They are distinguished based on the mass-to-charge ratio; it produces a

spectrum that provides a very detailed image of the chemical composi-

tion on surfaces of the sample.

How does this help obtain the high-resolution images on curved

surfaces like bullets or metal casing of a firearm?

Basically, when a bullet is fired, the metal casing experiences and

undergoes changes due to the environment as it is subjected to factors

such as high temperature, pressure, and friction. The propellant and the

powder residue generates a reaction process that ejects the bullet out of

the chamber.

These combined factors often result in removal, degradation, or

evaporation of the volatile compounds of fingermark residue like water,

lipid, amino acid, and obscuring, or smudging of the mark. The scientists

of the University of Nottingham state that these factors may complicate

the conventional retrieval of fingerprint marks such as cyanoacrylate

fuming and fluorescent staining.

The experts in the University of Nottingham conducted research for a

period of over 7 months and were able to obtain high-resolution images

of the fingerprint images, ridge characteristics, and the sweat pore

details, which was not the case in the conventional method such as

cyanoacrylate fuming and basic yellow 40 dye. The rotation stage is a sig-

nificant feature that helps study the fingerprint marks in detail.