Autonomous, transportable LIF based detection system for fast in situ classification of biological hazards

Abstract

In an effort to reduce the potential risk of human exposure to chemical or biological hazardous materials, the demand increases for a detection system which rapidly identifies possible threats from a distance to avoid direct human contact to these materials. Spectrally and time-resolved laser-induced fluorescence (LIF) with multiple excitation wavelengths has demonstrated to be a performant candidate for biological stand-off detection. These results can be used to develop small scale, transportable systems for in situ detection, which are simple in design and highly resolving. We present a technology demonstrating device for detection of biological agents on relevant surfaces. The compact and transportable system utilizes multi-wavelength excitation and is designed for a standoff distance between 3 and 10 m and fast simultaneous acquisition of full-featured, i.e. the spectral and time resolved, fluorescence response of the illuminated target. The surface-scanning technique of the apparatus allows for applied studies on mapping of contaminated surfaces. Additionally, intensive investigations on sensitivity requirements can be performed, such as on the required scanning speed and on the discrimination of LIF signals from hazards and carrier/background material. To this end we present detailed studies on the interplay between scanning speed and identification accuracy, minimizing the time for a complete scan of the site. With respect to realistic detection scenarios we discuss the capabilities of our system concerning the distinction between the contamination and the contamination carrier based on detailed measurements.