Encyclopedia of Scientific Dating Methods

2015 Edition
| Editors: W. Jack Rink, Jeroen W. Thompson

Alpha Spectroscopy

  • Jeroen W. ThompsonEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-94-007-6304-3_49


Alpha counting; Thick source alpha counting


Measurement of U and Th concentrations in environmental samples through detection of alpha particles emitted by isotopes in the U and Th decay chains.

Alpha particles emitted during radioactive decay are extremely short range (in minerals, micrometers) but deposit a significant quantity of energy. Therefore, the isotopes responsible for alpha emissions may be a large contributor to the overall absorbed radiation dose for a datable sample.

In order to measure the U and Th concentrations in a mineral, the sample is ground to a powder and deposited on a scintillator screen (mounted to a photomultiplier tube) or on to a semiconductor detector. Alpha particles deposit significantly more energy than beta particles or gamma rays, so unwanted counts are rejected through electronic processing of the signals recorded by the detector.

Although thin samples would provide better energy resolution (essentially no loss of energy due to...

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  2. Michael, C. T., Hein, A., Zacharias, N., and Kritidis, P., 2008. Disequilibrium estimations in the U and Th series by using thick source alpha-particle spectroscopy. Radiation Measurements, 43, 1149–1153.CrossRefGoogle Scholar
  3. Sjostrand, H., and Prescott, J. R., 2002. Thick source alpha counting: the measurement of thorium. Ancient TL, 20, 7–10.Google Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2015

Authors and Affiliations

  1. 1.Department of Medical Physics and Applied Radiation SciencesMcMaster UniversityHamiltonCanada