Abstract: Various embodiments of the present invention provide a method of detecting inaccessible radiation sources by measuring corresponding ions and excited molecules created by radiation, using LIDAR technology. The LIDAR system of the present invention employs a pulsed laser transmitter, a telescope receiver, and associated control and acquisition systems. Light propagates out from the laser transmitted and is directed into the volume surrounding the radioactive source, or the “ion cloud.” The ion cloud absorbs the transmitted light, which induces the non-fluorescing ions to fluoresce. Light from the ion cloud is then backscattered and the telescope receiver subsequently collects the photons from the backscattered light. The intensity of the fluorescence (determined by the photon count) is measured, which provides an indication of the number density of the ionized atoms. Algorithms can then be used to relate the measured ionization rates to the source activity.

Abstract: Various embodiments of the present invention provide a method of detecting inaccessible radiation sources by measuring corresponding ions and excited molecules created by radiation, using LIDAR technology. The LIDAR system of the present invention employs a pulsed laser transmitter, a telescope receiver, and associated control and acquisition systems. Light propagates out from the laser transmitted and is directed into the volume surrounding the radioactive source, or the “ion cloud.” The ion cloud absorbs the transmitted light, which induces the non-fluorescing ions to fluoresce. Light from the ion cloud is then backscattered and the telescope receiver subsequently collects the photons from the backscattered light. The intensity of the fluorescence (determined by the photon count) is measured, which provides an indication of the number density of the ionized atoms. Algorithms can then be used to relate the measured ionization rates to the source activity.