Extreme Solar Particle Storms: The hostile Sun by Fusa Miyake Ilya Usoskin Stepan Poluianov

Author:Fusa Miyake, Ilya Usoskin, Stepan Poluianov
Language: eng
Format: epub
ISBN: 9780750322324
Publisher: IOP Publishing
Published: 2019-12-02T16:00:00+00:00

5.1.2 Decay Counting

Decay counting is primarily applied to the analysis of radiocarbon (14C), as 14C has a comparably short half-life of 5730 years (Godwin 1962). The half-lives of 10Be and 36Cl are much longer, being about 1.39 and 0.3 millions of years, respectively, which makes it inefficiently long to wait for their decay to collect the necessary statistic. Because more than half a million decays of 14C must be detected for a high-precision measurement of a modern sample within a measurement time of two weeks, about 10 g of wood sample are required for that (Kromer & Münnich 1992). Decay counting is performed two different ways. In the first case, the cleaned sample material is combusted to CO2 and its decay is measured in a gas proportional counter (Kromer & Münnich 1992). For the alternative method of scintillation measurement, the sample is typically converted to benzene (Polach 1992). Both methods are powerful as they show a low background and allow high-precision results to be achieved with relatively cheap equipment. The downsides of the methods are the relatively large amount of material required and the laborious sample preparation.

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