Having spent a large chunk of my young adult life in Columbus, Ohio, Polaris to me is an overhyped, gigantic, crazily crowded mall just north of I-270. But to researchers at the University of Michigan, it’s the next big thing in neutralizing terrorist threats.
The Polaris detector is one of the few newly developed machines that does a lot more than indicating that a radioactive material is nearby. It can identify exactly what material the source is made of and can lead inspectors directly to it.
I’m sure this is a lot more efficient than carrying around a Geiger counter and hoping to get lucky.
The device works by using a kind of radiation detecting material called cadmium zinc telluride. As radioactive material breaks apart into more stable elements, they shoot off smaller pieces of protons, neutrons or highly energetic particles. This last group consists of alpha rays, beta rays and gamma rays. The latter is the most energetic of the group, and thus the most dangerous.
When the invisible particle hits a piece of the new detector, it causes a tiny flash of light, which photosensors pick up and record. By tracking the flashes of light through a series of the detectors, a computer can work out how energetic the particle is and the path of its flight. This information can then tell the user what type of material and exactly from which direction the gamma ray came from. In fact, it can superimpose a map of the most likely places the radioactive source is located on an existing image of the surroundings.
Though there are several projects building these types of devices, this one may be the most useful. Others make use of a substance called high-purity germanium, which must be kept at a constant -200 degrees Celsius in order to work.
So unless agents want to cart around a huge vat of liquid helium wherever they go, Polaris seems to be the best bet for the time being.