Laboratory study of the radioactivity from fission products in microscopic fallout particles

An experiment is described wherein simple γ-ray detection and analysis techniques were utilized to study the radioactivity in local precipitation. Gamma spectra from filtered particulate, evaporation residue, and water from a sample of freshly fallen snow were counted, and the relative amount of several radionuclides present were identified. These data show that several isotopes produced in the recent Chinese nuclear detonation (Lop Nor testing ground, Sinkiang Province, 17 November 1976) are observable. Furthermore the data are sufficient to estimate the date of the detonation and to determine some of the characteristics of the explosion