Smartphones are not as accurate as conventional radiation detectors, but they are still useful enough to detect radiation before it reaches dangerous levels. They can also be used for personal dose evaluations and as an alarm for the presence of high levels of radiation. CMOS and CCD cameras, which are used in smartphones, can detect radiation, including gamma rays and x-rays. Scientists have tested radiation detection applications on four smartphones and concluded that they work well enough to be a useful alert system for first responders. The cameras in mobile phones can detect gamma rays in the same way as they detect photons of visible light.
The radiation detection application uses the phone to record the number of times it detects an interaction and that number becomes the dose received by the phone. This setting contributes to generating sometimes large background noise against which it is necessary to detect the radiation signal. The end result is that smartphones are surprisingly useful as gamma radiation detectors (the camera body is likely to stop alpha and beta radiation). They can accurately determine the dose rate a person is exposed to and that the phone is sensitive enough to detect radiation at levels that are significant in a radiological event. Of course it won't be as sensitive as a normal detector, but it's definitely enough to detect radiation before it reaches deadly levels and is useful enough as a warning system, he says. For example, as a first line of detection for emergency services during an incident involving radiation.
