Single generator x-ray machines, which are more commonly used than multi-generator machines outside of major airports due to lower costs, still provide an effective means of screening bags and packages but have some limitations. While these machines can automatically detect explosives by placing a red box around suspicious areas, the detection is not perfect and explosives may be missed if they are obscured by clutter or placed farther away from the generator. Proper training is needed to understand these systems' capabilities and limitations so that operators can effectively detect threats.
1. Outside of the big airports almost everybody else that has a checkpoint for screening is using a
single generator cabinet x-ray system. The more advance models with multiple generators that
you see in the airports are too costly for courthouse or mail room working on a small budget.
Even those the single generators might not have as many bells and whistles as the more
expensive system they still provide you a very viable capability to look inside of a package or
persons bag. The key is you need to understand how a threat is going to respond in your x-ray
system and you staff trained on what they should be looking for.
Single generator cabinet x-rays have the ability to automatically detect any material that has
similar properties of an explosive. They do this by placing a RED BOX around the area in
question. The does not mean it is an explosive it just means the x-ray operator needs to conduct a
more detailed search of the area in question and look for any indicators of the components of an
improvised explosive device (IED). As a Former U.S. Marshal and Judicial Security Inspector I
trained our Court Security Officer at the Federal law Enforcement Training Center (FLETC) on
how to identify the components of an IED (battery, wire, switch, detonator, and explosive)
Studies have shown that x-ray automatic detection does improve an x-ray operator’s ability to
detect explosives, but you must understand it is not 100% effective. The operator cannot expect
the x-ray to always tell him where to look with the RED BOX. Many things can affect the x-rays
ability to automatically detect the explosive. One of the things that can affect auto-detection is
how much clutter is around the explosive material. This clutter can basically mask the explosive
and you will not get a RED BOX.
2. The other way a single generator can miss an explosive is if the person bag is placed on the belt
away from the side the generator is on. Many of the single generator systems have the generator
on one side of the x-ray and it shoots across at an angle vs directly up from the center of the unit.
What this causes is when anything is run through the x-ray the father away from the generator
side it is the smaller it will appear on the screen. This also shrinks the total surface area in pixels
of the explosive material making it too small to be auto-detected. In the below image you see real
C-4 explosive being tested and each time we move it farther and farther away from the side the
x-ray generator was on. You can see how it get smaller and smaller until the RED BOX no
longer works.
3. Training is key to understanding how to detect a threat with an x-ray system, so you must ensure
that your staff are being trained by experts. SVS Countermeasures staff are all Former U.S.
Marshals and worked in Judicial Security and provided training at FLETC on threat detection. If
your staff needs to be trained and you want to ensure they are trained by experts contact use at
the below link:
