A Simple Method for Early Detection of Fall-out

The ambient gamma ray background due to natural radioactivity is measured outdoors with a NaI(TI) crystal and a 256 channel analyser. A computer continuously updates the background count rates of 10 windows for reference purposes. The influence of atmospheric radon daughters washed out during precip...

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Bibliographic Details
Published in:Radiation protection dosimetry 1992-02, Vol.40 (2), p.103-109
Main Authors: Korbech, U., Nielsen, K.G.
Format: Article
Language:English
Subjects:
Earth, ocean, space
Exact sciences and technology
External geophysics
Meteorology
Particles and aerosols
Online Access:Get full text
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Summary:The ambient gamma ray background due to natural radioactivity is measured outdoors with a NaI(TI) crystal and a 256 channel analyser. A computer continuously updates the background count rates of 10 windows for reference purposes. The influence of atmospheric radon daughters washed out during precipitation is eliminated by stripping. Examination of the stripped gamma ray spectrum every 12 min. reveals the presence of artificial radioactive nuclides. Different methods for detection are examined. Measurements with artificial sources, and computer calculations with addition of fission product count rates to the measured count rates due to the natural background, show that the detectable exposure level varies from 4% to 9% of the average natural background. The exposure rate due to natural radioactivity may double due to radon daughter washout during heavy rain.
ISSN:0144-8420
1742-3406
1742-3406
DOI:10.1093/oxfordjournals.rpd.a081197