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16 pages, 5595 KB

Open AccessArticle

Activity Concentration of Radon, Thoron, and Their Decay Products in an Open System

by Krystian Skubacz

Atmosphere 2025, 16(5), 545; https://doi.org/10.3390/atmos16050545 - 5 May 2025

Cited by 2 | Viewed by 1737

The article presents a model for the simulation of changes over time in the activity concentrations of radon and thoron and their progeny in an open system. The results of these simulations can be helpful in adapting the calibration process to the object in which it is to be carried out and the calibrated devices. In such cases, the critical quantities are the volume of the object, the air flow rate, and the corresponding filtration efficiency in the devices. All these parameters were included in the differential equations, and their solutions indicate the extent to which nuclide concentrations may change during device operation, especially in small-volume objects. Moreover, especially in the case of thoron, this nuclide should be continuously supplied to the calibration chamber, which ensures greater stability during the experiment. The equations also consider the possibility of a constant supply of nuclides and the removal of nuclides from the object, which also allows the use of this model in flow-through chambers. Full article

(This article belongs to the Special Issue Atmospheric Radon Concentration Monitoring and Measurements (2nd Edition))

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13 pages, 3086 KB

Open AccessArticle

Modeling: Activity Concentration of Radon, Thoron, and Their Decay Products in Closed Systems

by Krystian Skubacz and Bogusław Michalik

Int. J. Environ. Res. Public Health 2022, 19(24), 16739; https://doi.org/10.3390/ijerph192416739 - 13 Dec 2022

Cited by 6 | Viewed by 3613

Abstract

The article presents a model for simulating changes in the activity concentration of radon and thoron as well as their progeny in closed or poorly ventilated systems. A system can be considered closed when a stream of radon and thoron flows into a space, but nothing comes out. It was also assumed that there may be devices or installations with a filtering system that would reduce the concentration of radon and thoron decay products. These assumptions may, therefore, correspond to a situation in which, in an isolated chamber, the calibration of radon hazard-monitoring devices is carried out, and nuclides are supplied from an emanation or flow through sources or well-isolated spaces in an environment where the source of nuclides is, for example, radon and thoron exhalation. The differential equations were formulated on the basis of the assumption that the activity concentration of radionuclides of concern in the space is uniform. The equations do not consider possible losses due to diffusion or the inertial or gravitational deposition of aerosols. If these phenomena have a limited impact on changes in the activity concentration of nuclides, the solutions provided may be used to simulate the activity concentration of radon and thoron and their decay products in any confined space assuming different boundary conditions. Full article

(This article belongs to the Topic Climate Change, Air Pollution, and Human Health)

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11 pages, 5067 KB

Open AccessArticle

The Determination of Radon/Thoron Exhalation Rate in an Underground Coal Mine—Preliminary Results

by Michał Bonczyk, Stanisław Chałupnik, Malgorzata Wysocka, Agata Grygier, Robert Hildebrandt and Zornitza Tosheva

Int. J. Environ. Res. Public Health 2022, 19(10), 6038; https://doi.org/10.3390/ijerph19106038 - 16 May 2022

Cited by 17 | Viewed by 2986

Abstract

The objective of this work was to perform a series of measurements of radon and thoron exhalation in the underground workings of an experimental coal mine. In the years 2012–2015, experiments on underground coal gasification were carried out in a coal mine, which caused, among other effects, damage to rock mass. Afterward, periodic increases in the concentration of potential alpha energy (PAEC) of radon decay products in the air were found, which could pose a hazard to miners. The question posed was whether the gasification experiment resulted in the increased migration of radon and thoron. If so, did it increase the radiation hazard to miners? The adaptation of the existing instrumentation to the specific conditions was conducted, and a series of measurements were made. It was found that the measured values of radon and thoron exhalation rates ranged from 3.0 up to 38 Bq·m⁻²·h⁻¹ for radon and from 500 up to 2000 Bq·m⁻²·h⁻¹ for thoron. Full article

(This article belongs to the Special Issue Environmental Radioactivity Monitoring and Measurements: Radon)

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16 pages, 1392 KB

Open AccessArticle

Geant4 Simulation of Precipitated Activity-to-γ-Dose Rate Conversion Factors for Radon and Thoron Decay Products

by Valentina Yakovleva, Grigorii Yakovlev, Roman Parovik, Sergei Smirnov and Aleksey Kobzev

Mathematics 2022, 10(3), 293; https://doi.org/10.3390/math10030293 - 19 Jan 2022

Cited by 2 | Viewed by 3005

Abstract

The results of modeling the conversion factor from rainfall-deposited unit activity of gamma-emitting radon and thoron daughter decay products to their created gamma-radiation dose rate as a function of height above the Earth’s surface using the Geant4 toolkit are presented in this paper. Thin layers of water, soil, and air, with the height of 0.1–10 mm, are considered as the source in order to examine whether the composition of the radiation source environment affects the simulation result. Cases with different absorber-atmosphere densities are simulated. The contribution of each radionuclide

^{212}

Bi,

^{214}

Bi,

^{212}

Pb,

^{214}

Pb and

^{208}

Tl to the total gamma background was determined. The dependence of dose rate growth during the precipitation period on the detector position in relation to the area covered by precipitation was investigated numerically. The obtained conversion factors are universal values, because do not depend on soil type (material) on which radionuclides are deposited by precipitation. These coefficients can be used for solving both direct tasks of radiation background recovery during precipitation and inverse tasks of determining the intensity and amount of precipitation by the known gamma background, as well as tasks to decipher the gamma background by the shape of the response to various phenomena. Also in this work, it is shown how thoron decay products can affect the response shape of gamma background on atmospheric precipitation. Full article

(This article belongs to the Section E4: Mathematical Physics)

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