The Nanonuke is a very small, yet highly sensitive radiation detector that fits into the smallest pocket, without pinching the wearer. It can connect to a smartphone via Bluetooth Low Energy (BLE). When connected to a phone, our GammaGuard app provides a rich user interface (UI). The user only interacts with the phone and NanoNuke remains ergonomically out of the way in the user’s pocket or at a remote location. This is ideal for covertly checking an area for radiation. The GammaGuard app can run in the background and alert the user of elevated radiation levels. The GammaGuard app allows for time and date stamped data logging with GPS coordinates. The data can be logged to a file on the phone and it can (optionally) be logged to web based databases, such as RadResponder, facilitating a coordinated incident response. Two NanoNukes can be connected to GammaGuard at the same time and can be used as a directional radiation detector (patent pending). Prior to NanoNuke, specialized direction finding equipment was large, bulky, complex, fragile and expensive.