No flow meter method for measuring radon exhalation from the medium surface with a ventilation chamber

Tan, Yanliang; Yuan, Hongzhi; Xie, Yuxi; Liu, Can; Liu, Xiaosong; Fan, Zhongkai; Kearfott, Kimberlee J.

doi:10.1016/j.apradiso.2020.109328

Cited by 6 publications

(5 citation statements)

References 11 publications

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“…The reference flux for this system is 1482 ± 50 mBq m -2 s -1 , which was measured using an activated charcoal box and Lucas cells. It is still operating, and some studies continue to use it (Tan & Xiao, 2013;Tan et al, 2020). Oak Ridge Associated Universities (Tennessee, USA) constructed a multilayer exhalation bed.…”

Section: State Of the Art Exhalation Bed Facilitiesmentioning

confidence: 99%

Characterizing the automatic radon flux Transfer Standard system Autoflux: laboratory calibration and field experiments

Grossi

Rábago

Chambers

et al. 2023

Preprint

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Abstract. High-quality, long-term measurements of terrestrial trace gas emissions are important for investigations of atmospheric, geophysical and biological processes to help mitigate climate change, protect the environment, and the health of citizens. High-frequency terrestrial fluxes of the radioactive noble gas 222Rn, in particular, are useful for validating radon flux maps, used to evaluate the performance of regional atmospheric models, to improve greenhouse gas emission inventories (by the Radon Tracer Method) and to determine Radon Priority Areas for radiation protection goals. A new automatic radon flux system (the Autoflux) was developed as a Transfer Standard (TS) to assist with establishing a traceability chain for field-based radon flux measurements. The operational characteristics and features of the system were optimized based on a literature review of existing flux measurement systems. To characterize and calibrate the Autoflux a bespoke radon Exhalation Bed (EB) facility was also constructed with the intended purpose of providing a constant radon emanation under a specific set of controlled laboratory conditions. The calibrated Autoflux was then used to transfer the derived calibration to a second continuous radon flux system under laboratory conditions, both instruments were then tested in the field and compared with modeled fluxes. This paper presents: i) a literature review of state-of-the-art radon flux systems and EB facilities; ii) the design, characterization and calibration of a reference radon EB facility; iii) the design, characterization and calibration of the Autoflux system; iv) the calibration of a second radon flux system (INTE_Flux) using the EB and Autoflux, with a total uncertainty of 9 % (k=1) for an average radon flux of ~1800 mBq m−2 s−1 under controlled laboratory conditions; and iv) an example application of the calibrated TS and INTE_Flux systems for in situ radon flux measurements which are then compared with simulated radon fluxes. Calibration of the TS under different environmental conditions and at lower reference fluxes will be the subject of a separate future investigation.

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Section: State Of the Art Exhalation Bed Facilitiesmentioning

confidence: 99%

Characterizing the automatic radon flux Transfer Standard system Autoflux: laboratory calibration and field experiments

Grossi

Rábago

Chambers

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…The reference flux for this system is 1482 ± 50 mBq m −2 s −1 , which was measured using an activated charcoal box and Lucas cells. It is still operating, and some studies continue to use it (Tan and Xiao, 2013;Tan et al, 2020). Oak Ridge Associated Universities (Tennessee, USA) constructed a multilayer exhalation bed.…”

Section: State-of-the-art Exhalation Bed Facilitiesmentioning

confidence: 99%

Characterizing the automatic radon flux transfer standard system Autoflux: laboratory calibration and field experiments

et al. 2023

View full text Add to dashboard Cite

Abstract. High-quality, long-term measurements of terrestrial trace gas emissions are important for investigations of atmospheric, geophysical and biological processes to help mitigate climate change and protect the environment and the health of citizens. High-frequency terrestrial fluxes of the radioactive noble gas 222Rn, in particular, are useful for validating radon flux maps and used to evaluate the performance of regional atmospheric models, to improve greenhouse gas emission inventories (by the radon tracer method) and to determine radon priority areas for radiation protection goals. A new automatic radon flux system (Autoflux) was developed as a transfer standard (TS) to assist with establishing a traceability chain for field-based radon flux measurements. The operational characteristics and features of the system were optimized based on a literature review of existing flux measurement systems. To characterize and calibrate Autoflux, a bespoke radon exhalation bed (EB) facility was also constructed with the intended purpose of providing a constant radon exhalation under a specific set of controlled laboratory conditions. The calibrated Autoflux was then used to transfer the derived calibration to a second continuous radon flux system under laboratory conditions; both instruments were then tested in the field and compared with modeled fluxes. This paper presents (i) a literature review of state-of-the-art radon flux systems and EB facilities; (ii) the design, characterization and calibration of a reference radon EB facility; (iii) the design, characterization and calibration of the Autoflux system; (iv) the calibration of a second radon flux system (INTE_Flux) using the EB and Autoflux, with a total uncertainty of 9 % (k = 1) for an average radon flux of ∼ 1800 mBq m−2 s−1 under controlled laboratory conditions; and (v) an example application of the calibrated TS and INTE_Flux systems for in situ radon flux measurements, which are then compared with simulated radon fluxes. Calibration of the TS under different environmental conditions and at lower reference fluxes will be the subject of a separate future investigation.

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“…The second model is the improved model without flow meter based on our previous research [10]; the difference between the two models is that whether there is a flow meter. Generally, the air radon concentration of the surrounding environment is below 20 Bq m −3 , which is much smaller than the radon concentration inside the chamber, and can be ignored, and then the radon concentration inside the chamber is [10]:…”

Section: Jinst 17 P10007mentioning

confidence: 99%

“…The measurement of radon exhalation rate is a means of finding source items in environmental radon pollution and treatment, and identifying whether the radioactive contents of building materials meets the national standards [7,8], which is crucial for estimating the radiation risk of various materials [9]. A variety of methods and instruments have been established to measure the radon exhalation rate, but the radon exhalation rate is easily disturbed by environmental conditions and sampling and is therefore difficult to reproduce and compare [10]. Unfortunately, the established radon exhalation standard facilities can't simulate any medium to be measured by adjusting the radon exhalation rate and effective decay constants as required.…”

Section: Introductionmentioning

confidence: 99%

Comparison of two models for measuring radon exhalation rate with a ventilation chamber by numerical simulation

et al. 2022

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Two models can be used to measure the radon exhalation rate with a ventilation chamber. The first is the custom model with a flow meter, and the second is the improved model without flow meter. As the established radon exhalation standard facilities can't simulate any medium to be measured by adjusting the radon exhalation rate and effective decay constants as required, numerical simulation is useful to compare the two models for measuring radon exhalation rate under different effective decay constants. Three different effective decay constants and two different radon exhalation rates were simulated for measuring radon exhalation rates, and the simulation results confirmed that the improved model is quick and accurate even when the radon exhalation rate is very low. While the custom model can only be used to calculate the radon exhalation rates when the ventilation rate is far larger than the effective decay constant, and it takes a long time for the radon concentration inside the ventilation chamber to be stable. Therefore, the improved model without flow meter is more accurate to measure the radon exhalation rate under different effective decay constants.

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No flow meter method for measuring radon exhalation from the medium surface with a ventilation chamber

Cited by 6 publications

References 11 publications

Characterizing the automatic radon flux Transfer Standard system Autoflux: laboratory calibration and field experiments

Characterizing the automatic radon flux Transfer Standard system Autoflux: laboratory calibration and field experiments

Characterizing the automatic radon flux transfer standard system Autoflux: laboratory calibration and field experiments

Comparison of two models for measuring radon exhalation rate with a ventilation chamber by numerical simulation

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