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External Radon Disturbance of 14C Measurements in Gas-Proportional Counters

Published online by Cambridge University Press:  18 July 2016

Magnus Hedberg
Affiliation:
Swedish Museum of Natural History, Laboratory for Isotope Geology, Box 50007 S-104 05, Stockholm, Sweden
Páll Theodórsson
Affiliation:
Science Institute, University of Reykjavík, Dunahaga 3, IS-107 Reykjavik, Iceland
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Abstract

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Low-level detector systems for 14C dating are frequently located in underground or basement laboratories to reduce the influence of cosmic radiation. However, if careful precautions are not taken, the presence of radioactive radon gas may severely disturb the analytical results. Measurements of the influence of radon on a proportional counter system, show that a radon level of 100 Bq m−3, a level not uncommon in basement rooms, is sufficient to produce an unacceptable uncertainty in the 14C results. Radon levels of up to 1500 Bq m−3 can be demonstrably reduced to about 30 Bq m−3, using a separate ventilation system that generates a slight overpressure in the laboratory.

Type
V. Advances in Measurement Techniques
Copyright
Copyright © the Department of Geosciences, The University of Arizona 

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