Explosives Vapors–Concentrating and Optoelectronic Detection

Abstract

Detection of explosives vapors is an extremely difficult task. The sensitivity of currently constructed detectors is often insufficient. The paper presents a description of an explosive vapors concentrator that improves the detection limit of some explosives detectors. These detectors have been developed at the Institute of Optoelectronics. The concentrator is especially dedicated to operate with nitrogen oxide detectors. Preliminary measurements show that using the concentrator, the recorded amount of nitrogen dioxide released from a 0.5 ng sample of TNT increases by a factor of approx. 20. In the concentrator an induction heater is applied. Thanks to this and because of the miniaturization of the container with an adsorbing material (approx. 1 cm 3 ), an extremely high rate of temperature growth is achieved (up to 500 °C within approx. 25 s). The concentration process is controlled by a microcontroller. Compact construction and battery power supply provide a possibility of using the concentrator as a portable device.

Test method for vapor collection and ion mobility detection of explosives with low vapor pressure

“…27 Explosives with low vapor pressure can be vaporized using various methods, including heating an explosive powder, nebulizing and heating an explosive solution, evaporating an explosive powder at room temperature for a long time, and using a vapor generator. [28][29][30][31][32] Mullen et al studied explosive vapor transport efficiency using aqueous solutions of TNT and RDX by nebulizing and heating them at 130 C for the preparation of explosive vapor, 28 whereas Li et al prepared explosive vapor by placing a solid-state explosive powder in a flask at 25 C for 48 h after sealing. 31 Vapor preparation by heating is not suitable for thermally labile chemicals; also, it is difficult to control the amount of vapor.…”

Barrier Detectors Versus Homojunction Photodiode

“…The complementary barrier infrared detector CBIRD and pBiBn allow to decrease the dark current and increase the quantum efficiency [11−17]. Among many new applications of HOT barrier detectors, the detection of explosives becomes extremely important due to an increased threat of terrorist attacks [18]. This paper presents the status of the barrier detectors and compares the performance of MWIR HgCdTe barrier detectors and unipolar barrier photodiodes.…”