A smart phone that can detect radiation may soon be helping the police to find the raw materials for radioactive “dirty bombs” before they are deployed.

The phones will glean data as the officers carrying them go about their daily business, and the information will be used to draw up maps of radiation that will expose illicit stores of nuclear material.

The detector is the brainchild of engineers at the Lawrence Livermore National Laboratory (LLNL) in California, US, who developed it in response to the rise in illicit trafficking of radioactive materials (see graphic). Customs officers at ports and airports already wear pagers that detect radiation. But any radioactive material not picked up by border controls can be hidden in towns and cities, with little chance that it will be found.

Now LLNL engineers funded by the US Department of Homeland Security have devised a way to tackle the problem. They have turned a multi-function internet cellphone into a wireless sensor that will feed data into a new type of radiation monitoring network that they are calling a RadNet.

The phone transmits radiation readings continuously over an always-on internet connection to a central computer. A GPS receiver in the phone labels the data with a time and location, allowing it to be used to build up a radiation map of a particular area.

More here.