Use APKPure App
Get Gamma Ray Calculator old version APK for Android
Save time with this exposure calculator for Iridium-192, Selinium-75 and Cobalt-60 sources.
No more need to calculate the formula or use of the "old-school plastic calculator"
Simply fill in the thickness, activity(in Curies) and source-film-distance and you get the correct exposure time.
R factor for different densities and film types.