Integrated Impactor/Detector for a High-Throughput Explosive-Trace Detection Portal

The design of a very-high-flow-rate inertial particle impactor with integrated sampling for use in a walk-through explosive-trace detection portal is presented. This impactor is designed to collect particles of explosives from the aerodynamic wake of a walking subject, which requires a sampling capability of ~ 1m³/s and must reliably collect particles of ≥ 5-μm diameter. An impactor cross-section of 0.3 × 0.3 m was used, with three linear slot nozzles and corresponding impactor blades. The central impactor blade has a rotating impaction surface with an integrated heater for automated thermal desorption of the impacted material. An ion mobility spectrometer is used to interrogate the desorbed vapor for trace explosives detection. The process of sampling a subject and interrogating its aerodynamic wake for explosives requires about 8 s totally, allowing very-high throughput sampling for security-screening purposes.