1. A radiation detection network, comprising: a central monitoring system having a data server connected to a wireless communications network; and a plurality of radiation detection instruments widely distributed in a geographic region, each instrument comprising: a mobile communications device having wireless means for communicating with the data server of the central monitoring system over the wireless communications network; a radiation detector operably connected to said mobile communications device for measuring the individual energies of detected photons; a clock-calendar operably connected to said mobile communications device for determining the time-date associated with each detected photon; and a locator operably connected to said mobile communications device for determining the location of said instrument associated with each detected photon, said mobile communications device adapted to transmit data of the individual photon energies and the corresponding detection time-dates and detection locations associated with each to the data server of said central monitoring system, wherein said central monitoring system includes means for collectively analyzing said data received from the plurality of radiation detection instruments, whereby a radiation source(s) may be identified and/or tracked.