Large area imaging of forensic evidence with MA-XRF

Area of Science:

• Forensic Science
• Analytical Chemistry
• Materials Science

Background:

• Conventional forensic techniques struggle with large or challenging evidence items.
• Elemental analysis is crucial for identifying and classifying forensic traces.
• Need for non-invasive methods with enhanced sensitivity and selectivity.

Purpose of the Study:

• Introduce macroscopic X-ray fluorescence (MA-XRF) for forensic trace analysis.
• Demonstrate MA-XRF's capability in detecting biological stains and gunshot residues (GSR).
• Explore MA-XRF for detailed forensic incident reconstruction.

Main Methods:

• Utilized macroscopic X-ray fluorescence (MA-XRF) for elemental signature analysis.
• Applied MA-XRF to large object areas like clothing and wall paneling.
• Employed high-resolution MA-XRF for detailed imaging and classification.

Main Results:

• MA-XRF detected human biological traces (blood, semen, saliva, sweat, urine) using elemental signatures (Fe, Zn, K, Cl, Ca).
• Successfully imaged and classified gunshot residues (GSR) with elemental mapping (Pb, Ba, Sr, K, Cl).
• Demonstrated non-invasive detection of bullet impact signatures through multiple layers.

Conclusions:

• MA-XRF provides a valuable chemical contrast for forensic trace detection on challenging evidence.
• MA-XRF enables detailed shooting incident reconstruction, including angle and ammunition type.
• MA-XRF is a powerful, non-invasive tool for forensic analysis of large items and layered evidence.