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Journal Articles

Evaluation of the intake of radon through skin from thermal water

Sakoda, Akihiro; Ishimori, Yuu; Tschiersch, J.*

Journal of Radiation Research, 57(4), p.336 - 342, 2016/07

 Times Cited Count:6 Percentile:40.54(Biology)

In general, the deposition of inhaled radon progeny on lung gives the largest dose when the dose evaluation is made for the so-called radon exposure. In this case, the dose from inhalation of radon itself is much lower than that from its progeny. Also, very little studies of the absorption of radon via skin have not been done so far. However, specific environments such as radon hot springs have the characteristics that radon concentration in water is significantly higher by a few orders than that in air. In the present study, a biokinetic model of radon into which its skin-absorption process was incorporated was developed to discuss the change in radon concentrations in tissues during and after bathing in thermal water. This derived dose was compared with other exposure routes from radon and its progeny.

Journal Articles

An Approach to discriminatively determine thoron and radon emanation rates for a granular material with a scintillation cell

Sakoda, Akihiro; Meisenberg, O.*; Tschiersch, J.*

Radiation Measurements, 89, p.8 - 13, 2016/06

 Times Cited Count:2 Percentile:14.27(Nuclear Science & Technology)

In the present study, the methodology for the discriminative determination of thoron and radon emanation rates from a granular material has been examined using a flow-through scintillation cell and so-called sandwich sample. The mathematical model was developed to differentiate total alpha counts into thoron- and radon-associated counts. This method was experimentally validated, and then the detection limits and uncertainties were evaluated to characterize this method. It was concluded that the present method is advantageous to a sample that has much higher $$^{226}$$Ra activity than $$^{224}$$Ra if the emanation fractions are similar between thoron and radon.

Journal Articles

Behavior of radon progeny produced in a scintillation cell in the flow-through condition

Sakoda, Akihiro; Meisenberg, O.*; Tschiersch, J.*

Radiation Measurements, 77, p.41 - 45, 2015/06

 Times Cited Count:6 Percentile:48.17(Nuclear Science & Technology)

When a scintillation cell is used for radon measurement, detection efficiencies for individual alpha emitters ($$^{222}$$Rn, $$^{218}$$Po and $$^{214}$$Po) are required depending on the methods of data analysis. The present study describes an attempt to obtain an empirical parameter which is necessary to calculate their individual detection efficiencies in the flow-through cell: the fraction of the progeny generated in the cell which is deposited onto the wall. As a result, an empirical formula was acquired to estimate the deposition fraction of $$^{218}$$Po as a function of flow rate. This result is helpful in understanding the characteristics of the scintillation cell. The empirical formula derived in this study can also be applied to predicting the behavior of thoron progeny ($$^{212}$$Pb and its progeny) in continuous thoron measurements with the flow-through scintillation cell.

Oral presentation

Review of the atmospheric radioactivity monitoring at Nuclear Science Research Institute, following the Fukushima accident

Okura, Takehisa; Feistenauer, P.*; Meisenberg, O.*; Shinonaga, Taeko*; Tschiersch, J.*

no journal, , 

The atmospheric radioactivity monitoring at Nuclear Science Research Institute, following the Fukushima accident was reviewed in this study. Comparison with measurement result of the filters at Helmholz Zentrum Muenchen (Germay) was made in order to discuss how to make an estimate of background under contaminated circumstance soon after the accident. Values of each other for samples with important level to estimate internal exposure was consistent; this points to that the adopted method to estimate background was appropriate. But some of samples with relative lower level were incompatible with each other. Penetration of radiocesium aerosols through HE-40TA was discussed with size distribution of radiocesium aerosols and characteristics of HE-40TA. Size distributions of radiocesium aerosols were evaluated experimentally, separated from HE-40TA and collected into a cascade impactor. The penetration was estimated by about 1% - 5%.

Oral presentation

Size distribution of radiocesium aerosols after the Fukushima accident collected at 120 km SSW of Fukushima Nuclear Power Plant

Okura, Takehisa; Meisenberg, O.*; Feistenauer, P.*; Shinonaga, Taeko*; Tschiersch, J.*

no journal, , 

Atmospheric radioactivity monitoring was made at Nuclear Science Research Institute, JAEA, following the Fukushima accident. Aerosol-bound radiocesium (Cs) was collected on paper filter (HE-40TA). In this study, to evaluate size distribution of the Cs, radioactive aerosols collected on HE-40TA was removed into distilled water, and then radioactive aerosols were extracted from the solution with a nebulizer and collected into a cascade impactor. The size distribution soon after the accident has one peak which is found around 0.3 $$mu$$m. Corresponded temporal decreasing Cs concentration, the second peak which has median of 1-2 $$mu$$m was developed besides ca. 0.3-$$mu$$m-median peak at sites around field. The size distribution collected at a site in woods has only one peak after also significant decreasing of Cs concentration. It is presumed that the coarser-median peak was attributed to resuspended radioactivity, considered on the basis of distribution of radioactive aerosols on the filters observed with autoradiography and reference articles.

Oral presentation

Approach to discriminatively determine radon and thoron emanation fractions with a scintillation cell

Sakoda, Akihiro; Meisenberg, O.*; Tschiersch, J.*

no journal, , 

The powder sandwich technique was recently developed to measure thoron (Rn-220) emanation fraction from a sample with high Ra-224 concentration. In this method, a sample was set between two filters, and then air passing through the filters was directly introduced to a detector. In the present study, this technique was expanded to discriminatively measure radon (Rn-222) and thoron emanation fractions using a scintillation cell. First, we made theoretical models that predict counts per time for each nuclide (radon, thoron, or their progeny). Then, analytical solutions for these models were fitted to experimental data to obtain radon and thoron emanation rates. This presentation describes mainly the rationale of our approach. Measurement examples for some samples are also shown and discussed.

Oral presentation

Dose estimates from radon absorbed via skin and its progeny deposited on skin in radon therapy; Comparison with different exposure pathways

Sakoda, Akihiro; Ishimori, Yuu; Tschiersch, J.*

no journal, , 

Some human studies have been made in radon-therapy facilities to measure the intake of radon via skin and the deposition of radon progeny onto skin. In the present study, with based on such empirical data, we addressed dose calculations for various organs and tissues due to these exposures. We have first developed mathematical models expressing the behavior of radon or its progeny in the body, and then optimized the values of parameters required. To compute dose coefficients, the activity of radon or its progeny in skin (and other organs and tissues) during and after the treatment was predicted with the optimized parameters. In the presentation, the results will be presented in detail and compared with other different pathways as inhalation that have ever been reported. The present work would contribute to one's understanding of radon exposure and its resulting doses from various viewpoints.

Oral presentation

Study of absorption of radon through skin

Sakoda, Akihiro; Ishimori, Yuu; Tschiersch, J.*

no journal, , 

In general, the deposition of inhaled radon progeny on lung gives the largest dose when the dose evaluation is made for the so-called radon exposure. In this case, the dose from inhalation of radon itself is much lower than that from its progeny. Also, very little studies of the absorption of radon via skin have not been done so far. However, specific environments such as radon hot springs have the characteristics that radon concentration in water is significantly higher by a few orders than that in air. In the present study, a biokinetic model of radon into which its skin-absorption process was incorporated was developed to discuss the change in radon concentrations in tissues during and after bathing in thermal water.

Oral presentation

Contribution of internal dose to the exposure in the Fukushima exclusion zone

Tschiersch, J.*; Yoshimura, Kazuya; Spielmann, V.*; Iijima, Kazuki; Shinonaga, Taeko*; Miyahara, Kaname

no journal, , 

Oral presentation

Potential inhalation dose due to remediation activities in the Fukushima exclusion zone

Tschiersch, J.*; Yoshimura, Kazuya; Spielmann, V.*; Hurkamp, K.*; Iijima, Kazuki; Shinonaga, Taeko*; Miyahara, Kaname

no journal, , 

Inhalation dose depends on the kind and amount of inhaled radionuclides, but also on the size of radioactive particles and the solubility of the radionuclides in the lungs. Initial measurements during decontamination provide experimental data of the main parameters. These are particle size distribution with activity median aerodynamic diameter (AMAD) and geometric standard deviation and the solubility in the lungs. The dose assessment is performed according ICRP lung model using the computer code IMBA professional. Doses determined from measured parameters are compared to those using ICRP default values. Variability is studied and the range of potential inhalation dose is assessed.

Oral presentation

Inhalation dosimetry; Physicochemical differences between primary plume and resuspended material

Tschiersch, J.*; Spielmann, V.*; Shinonaga, Taeko*; Hurkamp, K.*; Yoshimura, Kazuya; Okura, Takehisa; Iijima, Kazuki; Miyahara, Kaname

no journal, , 

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