Gamma-analysis of airborne particulates sampled in Youzhno-Sakhalinsk town at March - April 2011

TL;DR

This study analyzed airborne radioactive particulates in Youzhno-Sakhalinsk following the Fukushima accident, detecting isotopes like I-131, Cs-137, Cs-134, Te-132, and I-132, and examined gamma-ray spectral effects and measurement accuracy.

Contribution

First gamma-analysis of airborne particulates in Youzhno-Sakhalinsk post-Fukushima, identifying specific radionuclides and assessing measurement effects and accuracy.

Findings

Detected I-131 from March 23, 2011

Observed rise in Cs-137 and Cs-134 after April 3, 2011

Quantified gamma-gamma coincidence effects on measurements

Abstract

The experience of discovery of the radioactive products which have released into atmosphere of Sakhalin region from Fukushima Daiichi accident is presented. Sampling of airborne particulates and atmosphere fallout was carried out by means of the air ventilation set and horizontal gauze planchs, respectively. The HPGe detector was used for gamma analyses of the airborne samples. Since 23 March we confidently measured 131I in the airborne samples, after 03.04.2011 we also registered a rise of activity 137Cs and 134Cs. 132Te and 132I were discovered in ashen sample of the planch, which had exposed in Youzhno-Kurilk from 14 to 17 March. The effect of the pairs production when in the samples 208Tl presence, which emits gamma-quanta of 2615 keV, causes a rise in apparatus spectra of the peak corresponding to energy 1593 keV, which could be in error ascribed to 140La. It had been experimentally shown that the systematic reduction of 134Cs content in measuring samples due to effect of gamma - gamma coincidence did not exceed 7 % (for the detector and geometry of the measurement used).