The new RadioactivityCounter App is available now, I can offer 10 promocodes, but you need to write a PM to get it and leave a comment here at the same time. Users with access to a source and a comparison Geiger Counter device are prefered, so please write what you plan to test. Example on iPad2 with a 612 min background measurement, a energy hit is visible (either sun flare particle or cosmic). We tested and measured iPhone 3GS, iPhone 4, iPhone 4S, iPad 2, iPod 2 -- video camera mode required and a 4.3 or newer version. The tests were done a the Munich Helmholtz Research Center using a OB20 with a range from 10 uGy/h till 10 Gy/h (we did it in Gray instead of Sievert as its difficult to predict the aquivalent e dose rate. For beta and gamma rays roughly 1Gy = 1Sv. Alpha rays cannot be measured with the App, and only beta rays with higher energy (depends on the phone material). Below 1-10 uGy/h larger measurement times are required as the sensor area (camera) is very small and much smaller than a Geiger Counter, so less rays can hit the sensor to be counted and noise effects will add. In the image you see the clould mode like a cloud chamber you can see traces of the particles soemtimes circles etc. As the gamma rays are ionizing radiation (and beta rays) they leave traces in the camera semiconductor which can be measured.
only one was interested -- its not a fake RadioactivtyCounter is really working - - 9 codes still left (they will expire).
Here a nice video with an example of a vintage watch with radium hands and the iPhone to detect the impacts:
