Detection of hidden explosives is an inspection process that is non-destructive in nature. It is usually done to determine whether the container contains any explosive material. These are commonly deployed in airports, ports, and border control.
Various sampling processes are developed for detection of hidden explosives in public areas as they pose a threat to the population’s life. Explosive detection methods are related to different fields such as Physics, chemistry, biology, etc., and the detection methods include measuring explosive vapor pressure, nitrogen elements in explosives, and explosive coloration, etc.
This article further talks about the various technical methods such as bio-detection, explosive vapor detection, detection using multi-energy X-rays, direct detection of black powder, and many such methods employed to detect hidden explosives.
Detection Methods of Hidden Explosives
Various methods used for the purpose of detection of hidden explosives are as follows-
1. Bio-Detection Method
This method can provide evidence to distinguish between explosives and the other materials found by the reaction of organisms. When organisms such as bacteria and enzymes contact the explosive material, they change their color. Flies and insects are also used to detect explosives as they show fluorescence when they contact an explosive material.
2. Explosive Vapor Detection Method
These techniques include electron capture, ion mobility, gas chromatography, etc. There is often a fixed vapor pressure for most of the explosives. Most of the explosives are electronegative in nature. While entering the detector, the explosive compound captures a few of the electrons that form the negative ions, which causes a decrease in detector current.
This decrease in the current can then be identified by sound, light, or by a meter.
The problem with this method is that it cannot detect if the vapor pressure is low and cannot detect the hermetically sealed explosives.
3. Using Multi Energy X-Rays to Detect Explosives
X-rays play a vital role in the detection of explosives. X-ray technique is efficient in detecting discerning metal products and metal components present in the explosives. Various images are produced on the screen when the X-ray passes through different density materials, and hence materials can be determined according to the images formed on the screen.
4. Direct Detection of Black Powder
This method is a simple technique and can be produced in every place. Black powder can be detected by detecting the y – rays produced by K40 in black powder. For this method, an appropriate detecting crystal and suitable protection system should be selected.
5. Neutron Activation Analysis
In this method, explosives are detected by the radiation of thermal neutrons and fast neutrons. After the radiation by thermal neutrons, nitrogen in an explosive can produce y-rays. These specially designed machines bombard the suspected item or explosive with neutrons and then study the gamma radiation decay signatures to determine the chemical composition of a sample.
The efficient detector should be portable light weighted. However, it should be highly sensitive, and the anti-interference is powerful.
Despite the high sensitivity of few methods, the low volatility of many explosives and the high quality of their packaging make it challenging to be detected. False alarms caused by the interference of non-explosive factors can confuse inspectors.