Real-time detection of concealed chemical hazards under ambient light conditions using Raman spectroscopy

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Chemical Sensing

Background:

• Growing security threats necessitate advanced methods for detecting hazardous materials.
• Non-invasive techniques are crucial for screening opaque containers in real-time.
• Spatially offset Raman spectroscopy (SORS) offers a novel approach for subsurface analysis.

Purpose of the Study:

• To demonstrate a modified portable SORS sensor for in-field detection of concealed hazardous substances.
• To evaluate the sensor's performance under diverse background lighting conditions.
• To assess the rapid identification capabilities for various illicit and dangerous materials.

Main Methods:

• Development and deployment of a portable Spatially Offset Raman Spectroscopy (SORS) sensor.
• Concealment of diverse samples (explosive precursors, drugs, chemical warfare agent surrogate) within various packaging materials (plastic, paper, cloth).
• In-field measurements conducted under varied lighting conditions (incandescent, fluorescent, daylight).

Main Results:

• Successful identification of concealed substances against reference Raman spectra in under 60 seconds.
• Demonstrated efficacy of the portable SORS sensor across different packaging types and lighting environments.
• High accuracy in detecting hazardous materials, including explosive precursors, drugs, and an organophosphate insecticide.

Conclusions:

• The developed portable SORS sensor provides a rapid and non-invasive method for detecting concealed hazardous substances.
• The system is suitable for real-life security applications, including airports, mail facilities, and customs.
• This technology enhances security screening capabilities by enabling quick identification of dangerous materials.