Abstract
The paper is focused on the development of measurement technique and processing of signal for the detection of chemical, explosive, biological agents and its simulants using Engineered Quartz Enhanced Laser Photoacoustic Spectroscopy (QE-LPAS) technique. Hazardous materials like Sarin, TATP (Tri acetone tri-peroxide) and their simulants like DMMP (Dimethyl Methyl Phosphonate), Acetone, and atmospheric species were detected at 7 to 11 μm wavelength band. QE PAS technique is developed and demonstrated from a standoff distance of up to 30 meters in gaseous/vapourous and aerosols based on retro-reflector in ~2.0 ppm concentration. Hazardous biomolecules like Tryphatophan and DPA were detected on diffused aluminum adsorbed surface plate. Explosive and its simulants, TNT on adsorbed surface and DMMP, Nitrobenzene, Acetone were detected in vapour/aerosol form. A dedicated single screen, single user, user friendly Graphical User Interface (GUI) for controlling the entire system, acquisition and processing of the incoming signal and demonstration of results has been developed with the help of Laboratory Virtual Instrument Engineering Workbench (LABVIEW).
Highlights
The laser absorption spectroscopy has become rapidly growing area of research after the invention of Quantum Cascade (QC) laser [1]
Standoff Quartz Enhanced Laser Photo acoustic Spectroscopy (QELPAS) technique is emerging as a powerful technique for detection of hazardous chemicals, biological and explosive agents [11]
Quartz Enhanced Laser Photoacoustic Spectroscopy (QE-LPAS) System is developed based on the phase sensitive data acquisition for detection of hazardous biological, chemicals and explosive materials
Summary
The laser absorption spectroscopy has become rapidly growing area of research after the invention of Quantum Cascade (QC) laser [1]. Many vapor phase chemical direct Photo acoustic sensors based on QCL have been demonstrated [3]. Laser photo acoustic spectroscopy has been used for trace detection of vapors, gas and aerosols [5,6,7,8]. Standoff Quartz Enhanced Laser Photo acoustic Spectroscopy (QELPAS) technique is emerging as a powerful technique for detection of hazardous chemicals, biological and explosive agents [11]. Aim of the present work is to develop a technique based on QE-LPAS for the detection of hazardous molecules for the forensic application and homeland security. The present technology has the potential to get converted into a compact product for the field operation having capability to detect explosives, hazardous chemicals and bio-molecules in the form of vapor, aerosols and samples adsorbed on solid surfaces. The sensitivity of the Quart Crystal Tuning Fork (QCTF) detector in vacuum condition has been discussed
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