Emission probabilities of γ-rays associated with the decay of 229Th and its daughters

doi:10.1016/0883-2889(86)90062-6

International Journal of Radiation Applications and Instrumentation. Part A. Applied Radiation and Isotopes

Volume 37, Issue 2, 1986, Pages 139-147

https://doi.org/10.1016/0883-2889(86)90062-6 Get rights and content

Abstract

As an aid in the quantitative assay of ²²⁹Th by means of γ-ray spectrometry, we have made precise measurements of the emission probabilities of several γ rays from the decay of ²²⁹Th and seven from the decay of its daughters in the energy range from 40 to 808 keV. The decay-rate calibration of an isotopically separated source was obtained from the total α-emission rate as determined with an Au-Si surface-barrier detector gated to accept only the α particles from ²²⁹Th. The geometry of this detector was measured with a ²⁴⁹Cf source calibrated on a low-geometry proportional counter. The γ-ray emission rates were measured on calibrated Ge detectors for this calibrated ²²⁹Th source. The relative γ intensities were also measured for a chemically separated ²²⁹Th source, which allowed an assessment of the contributions from the daughter activities. The percentage uncertainties in the measured γ-emission probabilities range from 1.3 to 4.0%. Our results differ significantly from those of two recently published measurements. A comparison of these three sets of results is given.

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Emission probabilities of γ-rays associated with the decay of 229Th and its daughters

Abstract

Int. J. Appl. Radiat. Isot.

Int. J. Appl. Radiat. Isot.

Int. J. Appl. Radiat. Isot.

Int. J. Appl. Radiat. Isot.

Int. J. Appl. Radiat. Isot.

Int. J. Appl. Radiat. Isot.

Int. J. Appl. Radiat. Isot.

Emission probabilities of γ-rays associated with the decay of ²²⁹Th and its daughters