Development of Marinelli beaker standards containing thorium oxide and application for measurements of radioactive environmental samples

N. Lavi, Z. B. Alfassi

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Marinelli (reentrant) beakers are recommended for measurement of low-activity radioactive environmental samples, in both liquids and solid phases. The preparation of Marinelli beaker standards containing 232ThO2 in a secular equilibrium with its daughter nuclides was studied. Standards were prepared by mixing of known amounts of solid ThO2 and various solids (e.g. CaCO3) to reach desired density (e.g. 1.1 g/cm3 for CaCO3). Measurements of calibrated Marinelli standards with HPGe detector showed that the energy dependence of the efficiency is similar to that of a point source, i.e. an almost linear dependence of log efficiency vs. log energy in the 200-2000 keV range, however the parabolic correlation fits better. The validity of these standards was checked by comparison to three certified reference Marinelli standards containing radio-cesium, radio-potassium and 226Ra in environmental samples. Quite good agreement was obtained between our standards and the published certified data. The limit of detection for the determination of radio-cesium by γ-ray spectrometry under the prevailing experimental conditions is 0.07 Bq (1.9 pCi), for 1.0 kg of environmental samples.

Original languageEnglish
Pages (from-to)15-19
Number of pages5
JournalRadiation Measurements
Volume39
Issue number1
DOIs
StatePublished - 1 Jan 2005

Keywords

  • Calibration
  • Detection limits for radionuclides
  • Marinelli beakers
  • NORM concentration
  • Th
  • Thorium standards
  • Validation of homogenization

ASJC Scopus subject areas

  • Radiation
  • Instrumentation

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