Dynamic Multicomponent Optical Analyzer for Chemical Weapon (CW) Exposure Studies

We propose to build in Phase II a compact, rugged laser photoacoustic spectrometric (L-PAS) prototype sensor system (at technology readiness level TRL-6) for continuous, real-time broadband analysis of multiple chemicals. It will incorporate a tunable infrared quantum cascade laser (QCL), photoacoustic cell and air sampler system in a sealed decontamination-capable module and an efficient algorithm for rapid high sensitivity, multi-component CW agent measurements in under a minute. In Phase I we have utilized a laboratory L-PAS instrument to successfully demonstrate feasibility through CWA simulant measurements in clean dry air and with multiple interferents. Several developments crucial for building compact field-usable sensor were completed, including: room temperature continuous-wave QCL in 9.5-10.5µm range with >100mW output; single mode operation; mode-hop-free multi-step laser tuning over ~700nm wavelength range in <10sec with rapid (<30ms) settling between wavelengths; autonomous laser tuning software; and optimizing algorithms for retrieval of multi-component concentrations. Laboratory tests of L-PAS sensor performed with simulants DIMP and DMMP were analyzed to determine sensor performance: (DMMP detection limit <2ppb) and ROC curves. The prototype sensor will be field tested with simulants and agents in DoD test sites to qualify (TRL-6) and characterize the sensor after which it will be delivered to the sponsor.