Use of induced radionuclides for recognition of tracks of nuclear explosions carried out at the Semipalatinsk test site

The study was performed to show the ability to recognize fallout tracks from nuclear explosions on Semipalatinsk Test Site by using ratios of fission and neutron activation products as 'markers' of tracks. In the current period long-lived products of neutron activation of rocks - '152Eu (half-life 13.3 y), 154Eu (8,6 y), 60Co (5,3 y) - can serve for recognition of tracks from ground-surface and underground (with rock outburst) nuclear explosions. Index P154,152 = 154/152 (ratio of 154Eu to 152Eu activities in the deposition) also is a sensitive indicator of explosion conditions - type of a charge (fission, fusion), arrangement (ground-surface, underground) etc. The first nuclear test (29 Aug. 1949) was considered as the case study in attempt to identify its deposition track in the Altai region area using expected levels of induced radionuclides 152Eu and 154Eu (P154,152 = 0.035) in soil. (author)