Our Passive Portal™ (Zero-Radiation) uses advanced passive sensors to detect common metallurgy used in knives, firearms, and other weapons, without the requirement of emitting electromagnetic-radiation of any kind. A passive sensor is an electronic device that responds to input directly from the physical environment that it is placed in. This means that passive sensors can gather specific data through the detection of vibrations, light, electromagnetic-radiation, heat, cold, or other phenomena occurring in that environment, with Zero-Emissions. Examples of passive sensors include: thermostats and thermometers, infrared motion sensors, common smoke detectors, and radiation monitors. With our Passive Portal™, we non-invasively detect weapons and other ferromagnetic items by reading the subtle changes that these items cause in the Earth’s magnetic field while they pass through the Portal.

In contrast to our Passive Scanning Technology, existing metal detection systems currently on the market use what is called active sensing. This means that they emit electromagnetic-radiation of some form, including radio waves, micro and millimeter-wavelength waves, and X-rays. In active sensing systems, an electromagnetic-radiation signal is typically emitted from one side of the scanner to the other side of the scanner, passing directly through the person being scanned. These systems then read the variations, or loss of transmission, from the “sent” side to “receive” side, much in the same way as an X-ray machine emits X-rays through a broken arm to expose the film on the other side of the arm showing the broken bone. While these active scanning technologies are commonly used, there is no evidence to support that they are safe. There are many studies that identify the long-term effects of exposure from electromagnetic-radiation, which has been shown to have caused cancer in other applications. Here is a white paper further discussing this issue.