An unattended device for high-voltage sampling and passive measurement of thoron decay products

Journal Article · Sat Feb 15 04:00:00 EST 2014 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4865163· OSTI ID:22255047

Gierl, Stefanie; Meisenberg, Oliver; Wielunski, Marek; Tschiersch, Jochen ^[1]; Haninger, Thomas ^[2]

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1. Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstädter Landstr. 1, 85764 Neuherberg (Germany)
2. Helmholtz Zentrum München, German Research Center for Environmental Health, Auswertungsstelle für Strahlendosimeter, Otto-Hahn-Ring 6, 81739 München (Germany)

An integrating measurement device for the concentration of airborne thoron decay products was designed and calibrated. It is suitable for unattended use over up to several months also in inhabited dwellings. The device consists of a hemispheric capacitor with a wire mesh as the outer electrode on ground potential and the sampling substrates as the inner electrode on +7.0 kV. Negatively charged and neutral thoron decay products are accelerated to and deposited on the sampling substrates. As sampling substrates, CR39 solid-state nuclear track detectors are used in order to record the alpha decay of the sampled decay products. Nuclide discrimination is achieved by covering the detectors with aluminum foil of different thickness, which are penetrated only by alpha particles with sufficient energy. Devices of this type were calibrated against working level monitors in a thoron experimental house. The sensitivity was measured as 9.2 tracks per Bq/m{sup 3} × d of thoron decay products. The devices were used over 8 weeks in several houses built of earthen material in southern Germany, where equilibrium equivalent concentrations of 1.4–9.9 Bq/m{sup 3} of thoron decay products were measured.

• OSTI ID: 22255047
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 2 Vol. 85; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ABUNDANCE
ALPHA DECAY
ALPHA PARTICLES
ALUMINIUM
CONCENTRATION RATIO
DAUGHTER PRODUCTS
HOUSES
PARTICLE TRACKS
RADIOECOLOGICAL CONCENTRATION
RADON 220
SAMPLING
SUBSTRATES