Portable vapor generator for the calibration and test of explosive detectors

The explosive vapor trace detectors deployed in the field require frequent verification and calibration to guarantee their accurate operation. In this paper we describe the latest advancements in the use of precision micro-dispensing technology for explosive vapor generation. The portable explosive vapor generator uses digitally controlled ink-jet dispensing to precisely eject minute amounts of dilute explosive solutions and convert them into vapor by placing them on a heater. The amount of explosive delivered to the detectors can be controlled by the number of drops (dose mode-specified number of drops is generated) and the frequency of the droplet generation continuous mode-droplets are generated continuously at fixed frequency. The control for the heater temperature allows setting specific temperatures, but also permits specification of temperature profiles. By using a small thermal capacitance heater it is possible to achieve very sharp temperature increases. The ability to precisely control the heater temperature over a wide range permits the generation of vapors for all common explosives.