Principles of UV-gamma coincidence spectrometry

With conventional methods, samples containing alpha-particle-emitting nuclides are difficult to detect and characterize from distances greater than a few centimetres. One promising technique is to observe alpha particles indirectly by utilizing alpha-induced ultraviolet (UV) photons. While absorbing in air, the energy of alpha particles is transferred to atmospheric molecules, leading to their ionization and excitation. In this work, UV photons generated in the relaxation of nitrogen molecules were used to trigger a gamma-ray spectrometer. This UV approach allows the focusing of gamma-ray measurements on a certain point containing alpha emitters. The present paper demonstrates that the new measurement principle works and has the potential to be developed for both in-field and laboratory applications.