Remote measurement and calibration of alpha-emitting radionuclides through the utilization of characteristic ultraviolet fluorescence

During the decommissioning of nuclear facilities and spent fuel reprocessing, conventional alpha particle detectors are insufficient for accurately measuring the emissivity of alpha particles due to their high radiation intensity and complex nuclide types. The air fluorescence method is developed to detect the α particle emissivity through measuring the intensity of ultraviolet fluorescence generated by the interaction between α particles and nitrogen or other inert gas mediums. This method offers advantages such as long detection range and immunity to γ radiation interference. The measurement results are primarily influenced by factors including α particle energy, detection distance, and gas medium composition, with photon noise and detection distance determining the detection limit. The obtained results indicate that: In the condition of measured in darkness, measurement time for 1000s, and distance for 1 m, The minimum detection limit for α sources is 7.6 kBq with a relative standard uncertainty of 10%.