[[ “terahertz radiation, a high-frequency electromagnetic natural energy”
I did a google and there isn’t much definitive about it but it supposedly is less dangerous then x-rays. ]]
You’re misunderstanding how this works.
The device the police will use emits no radiation or energy _towards_ the subject at whom it’s being pointed.
It merely detects energy that is being radiated by the person. Hence, “electromagnetic NATURAL energy”.
The purpose is to bypass the the Constitutional protection of [unreasonable] search without reasonable suspicion. There is no “search”, per se (as there would be if the device in question transmitted a of signal _toward_ the subject, which would strike the subject and then be reflected back to the device for analysis.
Instead, the new device becomes a “passive observer” of something emitted by the individual subject (in this case, natural emissions given off by the human body). Just as a police officer who observed someone doing an illegal activity (such as breaking into a car) would have “probable cause” to apprehend the suspect, the terahertz scanner “observes” in its own way, and when it indicates to the officer that something “gun-like” is being carried by the individual, probable cause now exists to question the individual about same.
This is the rationale you will hear when the legality of these devices is argued in court.
If that were the case then a camera could be implanted in every house w/o the owner's consent because the camera only detects light emissions [and reflections] from other sources.