Improving the detection limit in lung counting with a segmented HPGe detector

A segmented High-Purity Germanium (HPGe) detector with a thin front segment together with various active and passive shield configurations was simulated with the aim of reducing the level of background events in lung counting applications. Eight different detector models were tested in a Geant4 simu...

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Bibliographic Details
Published in:Applied radiation and isotopes 2024-08, Vol.210, p.111377-111377, Article 111377
Main Authors: Jutila, Henri, Greenlees, Paul, Torvela, Tiina, Muikku, Maarit
Format: Article
Language:English
Subjects:
Geant4 simulation
Lung counting
MDA
Segmented HPGe detector
Voxel phantom
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Summary:A segmented High-Purity Germanium (HPGe) detector with a thin front segment together with various active and passive shield configurations was simulated with the aim of reducing the level of background events in lung counting applications. Eight different detector models were tested in a Geant4 simulation environment in a scenario where inhaled 241Am activity was deposited in the lungs of an ICRP adult reference computational phantom. In lung counting measurements, the Compton continuum in the spectrum is generated by the natural and man-made radionuclides inside the human body and the natural background radiation from the environment. The reduction in Minimum Detectable Activity (MDA) using the segmented HPGe detector combined with an active shield compared to a model with a single germanium crystal was investigated. A reduction in MDA up to 30% and 66% was obtained for internal and external sources, respectively. The results show that the detection limit and/or the measurement time in lung counting can be reduced using such a detector configuration. Furthermore, combining the segmented HPGe detector with an active shield would be particularly useful in field measurements. •A segmented HPGe detector has been modeled in a Geant4 environment.•Natural and man-made radionuclides inside a ICRP computational phantom were simulated.•Unremovable background component is always present in the lung counting spectrum.•The background generated by internal and external sources was greatly reduced.•The MDA of 241Am could in turn be reduced up to 30 % and 66 %, respectively.
ISSN:0969-8043
1872-9800
DOI:10.1016/j.apradiso.2024.111377