Debris from the Sixth Chinese Nuclear Test

Abstract

DURING 1967, the Chinese People's Republic conducted two nuclear tests, its sixth and seventh. Nuclear debris from these tests eventually reached Sweden and was collected and examined as part of our routine. Ground level air and precipitation are sampled at several stations spread over Sweden. High altitude air above and below the tropopause is sampled in cooperation with the Royal Swedish Air Force. The radioactive particles thus collected are examined by γ-spectrometry and β-counting. “Reversal-autoradiographic” methods^1,2 make it possible to examine the particles under the microscope and to investigate colour, form, size and specific activity.