Development of 222 Rn Emanation Sources with Integrated Quasi 2π Active Monitoring

Florian Mertes, Stefan Röttger and Annette Röttger
Additional contact information
Florian Mertes: Physikalisch-Technische Bundesanstalt, National Metrology Institute, 38116 Braunschweig, Germany
Stefan Röttger: Physikalisch-Technische Bundesanstalt, National Metrology Institute, 38116 Braunschweig, Germany
Annette Röttger: Physikalisch-Technische Bundesanstalt, National Metrology Institute, 38116 Braunschweig, Germany

IJERPH, 2022, vol. 19, issue 2, 1-22

Abstract: In this work, a novel approach for the standardization of low-level 222 Rn emanation is presented. The technique is based on the integration of a 222 Rn source, directly, with an α-particle detector, which allows the residual 222 Rn to be continuously monitored. Preparation of the device entails thermal physical vapor deposition of 226 RaCl 2 directly onto the surface of a commercially available ion implanted Si-diode detector, resulting in a thin-layer geometry. This enables continuous collection of well resolved α-particle spectra of the nuclei, decaying within the deposited layer, with a detection efficiency of approximately 0.5 in a quasi 2π geometry. The continuously sampled α-particle spectra are used to derive the emanation by statistical inversion. It is possible to achieve this with high temporal resolution due to the small background and the high counting efficiency of the presented technique. The emanation derived in this way exhibits a dependence on the relative humidity of up to 15% in the range from 20% rH to 90% rH. Traceability to the SI is provided by employing defined solid-angle α-particle spectrometry to characterize the counting efficiency of the modified detectors. The presented technique is demonstrated to apply to a range covering the release of at least 1 to 210 222 Rn atoms per second, and it results in SI-traceable emanation values with a combined standard uncertainty not exceeding 2%. This provides a pathway for the realization of reference atmospheres covering typical environmental 222 Rn levels and thus drastically improves the realization and the dissemination of the derived unit of the activity concentration concerning 222 Rn in air.

Keywords: 222 Rn emanation; physical vapor deposition; silicon detectors (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/1660-4601/19/2/840/pdf (application/pdf)
https://www.mdpi.com/1660-4601/19/2/840/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jijerp:v:19:y:2022:i:2:p:840-:d:723341

Access Statistics for this article

IJERPH is currently edited by Ms. Jenna Liu

More articles in IJERPH from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().