An experimental approach to efficiency calibration for gamma-ray spectrometric analysis of large air particulate filters

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• 作者：Elio Tomarchio ; ^{elio.tomarchio@unipa.it}
• 关键词：Efficiency calibration ; Air particulate ; Gamma-ray spectrometry ; HPGe detectors
• 刊名：Radiation Physics and Chemistry
• 出版年：2013
• 出版时间：April, 2013
• 年：2013
• 卷：85
• 期：Complete
• 页码：53-58
• 全文大小：525 K

文摘

A full-energy-peak efficiency (FEPE) calibration procedure for gamma-ray spectrometric analysis of air particulate samples collected on large filters is described herein. The experimental results are obtained for an unconventional measurement geometry, termed a ¡°packet-sample¡±. The sample is obtained from a large cellulose filter (45 cm¡Á45 cm) used to collect air particulate samples that is resized to dimensions suitable for spectrometric measurements (6 cm¡Á6 cm¡Á0.7 cm). To determine the FEPEs, many standards were created, i.e., some filters containing a small amount of ThO₂ and others containing a known amount of KCl.

Efficiency curves obtained through best fits to experimental data for three high-purity germanium (HPGe) detectors, one of them for X-ray measurement, cover the energy range from 40 keV to 2600 keV. To validate the efficiency calibration procedure two experimental tests with the use of calibrated sources were conducted and, as application example, airborne concentrations of ¹³¹I (particulate matter), ¹³⁴Cs and ¹³⁷Cs at Palermo (Italy) in the days following the Fukushima accident in Japan were evaluated.