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Prof. Shinji Tokonami
Hirosaki University

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Research Keywords & Expertise

0 Aerosol Science
0 Health Physics
0 Radiation Dosimetry,
0 Radiation detection
0 Environmental Radioactivity

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Short Biography

Radon and Thoron Parallel Measurements in Dwellings Nearby a Closed Hungarian Uranium Mine C Nemeth, V Jobbágy, N Kávási, J Somlai, T Kovács, S Tokonami nukleonika 55 (4), 459-462 6 2010 Natural and Artificial Sources of Radioactivity in Poland M Janik, S Tokonami Japanese Journal of Health Physics 44 (1), 116-121 06/2009 Generation and Control of Radon from Soil M Hosoda, A Sorimachi, S Tokonami, T Ishikawa, SK Sahoo, NM Hassan 12th International Congress of the International Radiation Protection 6 2008 Characteristics of Indoor Radon and Thoron Concentrations in Cave Dwellings In Gansu Province, China A Sorimachi, S Tokonami, Y Omori, M Janik, K Iwaoka, T Ishikawa, Q Sun Radiation Protection Dosimetry 184 (3-4), 457-462 5 2019 Annual Effective Dose Assessment Due to Radon and Thoron Progenies in Dwellings of Kilimambogo, Kenya C Nyambura, S Tokonami, NO Hashim, MW Chege, T Suzuki, H Kudo Radiation Protection Dosimetry 184 (3-4), 430-434 5 2019 Investigation of External Radiation Doses During Residents’ Temporal Stay to Namie Town, Fukushima Prefecture T Tsujiguchi, Y Shiroma, T Suzuki, Y Tamakuma, M Yamaguchi, K Iwaoka Radiation Protection Dosimetry 184 (3-4), 514-517 5 2019

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Journal article
Published: 10 August 2021 in Atmosphere
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A total of 223 sand samples collected from seven provinces in Northeastern Thailand were analyzed for their gamma radioactivity from naturally occurring radioactive materials (NORMs), and the data were used to calculate the concentrations of Ra-226, Th-232, and K-40. Radiological safety indicators such as the indoor external dose rates (Din), the annual indoor effective dose (Ein), the activity concentration index (I), the radium equivalent activity (Raeq), the external hazard index (Hex), the internal haphazard index (Hin), and the excess lifetime cancer risk (ELCR) were calculated. The activity concentrations were found to be 36 ± 10 Bq/kg for Ra-226, 2.64 ± 0.58 Bq/kg for Th-232, and 323 ± 168  Bq/kg for K-40. Din is 62 ± 23 nGy/h. The Ein is 0.30 ± 0.11 mSv/y. The activity concentrations and other indicators were reported by each province and compared with the safety standards and are found to be within the safe limits in this study. The results can be used to develop the standard guideline levels for choosing building materials in Thailand.

ACS Style

Phachirarat Sola; Uthaiwan Injarean; Roppon Picha; Chutima Kranrod; Chunyapuk Kukusamude; Shinji Tokonami. Measurement of NORM in Building Materials to Assess Radiological Hazards to Human Health and Develop the Standard Guidelines for Residents in Thailand: Case Study in Sand Samples Collected from Seven Northeastern Thailand Provinces. Atmosphere 2021, 12, 1024 .

AMA Style

Phachirarat Sola, Uthaiwan Injarean, Roppon Picha, Chutima Kranrod, Chunyapuk Kukusamude, Shinji Tokonami. Measurement of NORM in Building Materials to Assess Radiological Hazards to Human Health and Develop the Standard Guidelines for Residents in Thailand: Case Study in Sand Samples Collected from Seven Northeastern Thailand Provinces. Atmosphere. 2021; 12 (8):1024.

Chicago/Turabian Style

Phachirarat Sola; Uthaiwan Injarean; Roppon Picha; Chutima Kranrod; Chunyapuk Kukusamude; Shinji Tokonami. 2021. "Measurement of NORM in Building Materials to Assess Radiological Hazards to Human Health and Develop the Standard Guidelines for Residents in Thailand: Case Study in Sand Samples Collected from Seven Northeastern Thailand Provinces." Atmosphere 12, no. 8: 1024.

Journal article
Published: 28 July 2021 in Atmosphere
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Recently, some commercially available active-type radon–thoron monitors were developed; however, their performance has not been characterized. This article presents the characteristics of three commercially available active-type radon–thoron monitors (RAD7, Radon Mapper, and AlphaGUARD) at different sampling flow rates. The thoron concentration measured by the monitors was compared with the reference value measured by a grab sampling method. As a result, the ratio of the measured concentration to the reference increased with flow rate for the RAD7 and the Radon Mapper although that of the AlphaGUARD decreased. The difference may be attributed to the coefficients used in the calculation and the measurement time scheme. The results indicate the importance of the sampling flow rate in thoron measurement. Monitoring of flow rate at the measurement and periodic calibration at multiple sampling flow rates should be conducted for quality assurance and quality control of the measurand.

ACS Style

Yuki Tamakuma; Chutima Kranrod; Yuto Jin; Hiromu Kobayashi; Eka Nugraha; Aoi Sanpei; Mizuki Kiso; Hiroki Hashimoto; Ryoju Negami; Masahiro Hosoda; Shinji Tokonami. Characterization of Commercially Available Active-Type Radon–Thoron Monitors at Different Sampling Flow Rates. Atmosphere 2021, 12, 971 .

AMA Style

Yuki Tamakuma, Chutima Kranrod, Yuto Jin, Hiromu Kobayashi, Eka Nugraha, Aoi Sanpei, Mizuki Kiso, Hiroki Hashimoto, Ryoju Negami, Masahiro Hosoda, Shinji Tokonami. Characterization of Commercially Available Active-Type Radon–Thoron Monitors at Different Sampling Flow Rates. Atmosphere. 2021; 12 (8):971.

Chicago/Turabian Style

Yuki Tamakuma; Chutima Kranrod; Yuto Jin; Hiromu Kobayashi; Eka Nugraha; Aoi Sanpei; Mizuki Kiso; Hiroki Hashimoto; Ryoju Negami; Masahiro Hosoda; Shinji Tokonami. 2021. "Characterization of Commercially Available Active-Type Radon–Thoron Monitors at Different Sampling Flow Rates." Atmosphere 12, no. 8: 971.

Article
Published: 25 July 2021 in Journal of Radioanalytical and Nuclear Chemistry
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Some areas around the world have anomalies with high natural radiation that may affect public health due to chronic-low-dose radiation exposure. In the paper, we summarized several studies that find Mamuju, Indonesia, a unique high natural radiation area. The majority of the relevant papers are about monitoring, main sources, and influential factors for the enhancement of radon and dose assessments. Under these circumstances, the Mamuju region is regarded as a promising area for conducting epidemiological studies, and it will provide a unique opportunity for improving and expanding low-dose-rate data on human health effects.

ACS Style

Eka Djatnika Nugraha; Masahiro Hosoda; Yuki Tamakuma; Chutima Kranrod; June Mellawati; Naofumi Akata; Shinji Tokonami. A unique high natural background radiation area in Indonesia: a brief review from the viewpoint of dose assessments. Journal of Radioanalytical and Nuclear Chemistry 2021, 1 -8.

AMA Style

Eka Djatnika Nugraha, Masahiro Hosoda, Yuki Tamakuma, Chutima Kranrod, June Mellawati, Naofumi Akata, Shinji Tokonami. A unique high natural background radiation area in Indonesia: a brief review from the viewpoint of dose assessments. Journal of Radioanalytical and Nuclear Chemistry. 2021; ():1-8.

Chicago/Turabian Style

Eka Djatnika Nugraha; Masahiro Hosoda; Yuki Tamakuma; Chutima Kranrod; June Mellawati; Naofumi Akata; Shinji Tokonami. 2021. "A unique high natural background radiation area in Indonesia: a brief review from the viewpoint of dose assessments." Journal of Radioanalytical and Nuclear Chemistry , no. : 1-8.

Article
Published: 16 July 2021 in Scientific Reports
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Mamuju is one of the regions in Indonesia which retains natural conditions but has relatively high exposure to natural radiation. The goals of the present study were to characterize exposure of the entire Mamuju region as a high natural background radiation area (HNBRA) and to assess the existing exposure as a means for radiation protection of the public and the environment. A cross-sectional study method was used with cluster sampling areas by measuring all parameters that contribute to external and internal radiation exposures. It was determined that Mamuju was a unique HNBRA with the annual effective dose between 17 and 115 mSv, with an average of 32 mSv. The lifetime cumulative dose calculation suggested that Mamuju residents could receive as much as 2.2 Sv on average which is much higher than the average dose of atomic bomb survivors for which risks of cancer and non-cancer diseases are demonstrated. The study results are new scientific data allowing better understanding of health effects related to chronic low-dose-rate radiation exposure and they can be used as the main input in a future epidemiology study.

ACS Style

Eka Djatnika Nugraha; Masahiro Hosoda; Kusdiana; Untara; June Mellawati; Nurokhim; Yuki Tamakuma; Abarrul Ikram; Mukh Syaifudin; Ryohei Yamada; Naofumi Akata; Michiya Sasaki; Masahide Furukawa; Shinji Yoshinaga; Masaru Yamaguchi; Tomisato Miura; Ikuo Kashiwakura; Shinji Tokonami. Comprehensive exposure assessments from the viewpoint of health in a unique high natural background radiation area, Mamuju, Indonesia. Scientific Reports 2021, 11, 1 -16.

AMA Style

Eka Djatnika Nugraha, Masahiro Hosoda, Kusdiana, Untara, June Mellawati, Nurokhim, Yuki Tamakuma, Abarrul Ikram, Mukh Syaifudin, Ryohei Yamada, Naofumi Akata, Michiya Sasaki, Masahide Furukawa, Shinji Yoshinaga, Masaru Yamaguchi, Tomisato Miura, Ikuo Kashiwakura, Shinji Tokonami. Comprehensive exposure assessments from the viewpoint of health in a unique high natural background radiation area, Mamuju, Indonesia. Scientific Reports. 2021; 11 (1):1-16.

Chicago/Turabian Style

Eka Djatnika Nugraha; Masahiro Hosoda; Kusdiana; Untara; June Mellawati; Nurokhim; Yuki Tamakuma; Abarrul Ikram; Mukh Syaifudin; Ryohei Yamada; Naofumi Akata; Michiya Sasaki; Masahide Furukawa; Shinji Yoshinaga; Masaru Yamaguchi; Tomisato Miura; Ikuo Kashiwakura; Shinji Tokonami. 2021. "Comprehensive exposure assessments from the viewpoint of health in a unique high natural background radiation area, Mamuju, Indonesia." Scientific Reports 11, no. 1: 1-16.

Research article
Published: 06 June 2021 in Annals of the ICRP
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This paper does not necessarily reflect the views of the International Commission on Radiological Protection. Several radiation monitoring research projects are underway on dose assessment, biological analysis, and risk communication under an agreement with Namie Town. Indoor radon and thoron progeny concentrations have been measured using passive-type monitors to estimate internal doses due to inhalation. In addition, airborne radiocaesium concentrations at five points in Namie Town have been analysed using a high-purity germanium detector to estimate internal doses for comparison with radon. External radiation doses from natural and artificial radionuclides have also been estimated using an in-situ gamma-ray spectrometer. Other support activities are mentioned briefly in this article,

ACS Style

Shinji Tokonami; Tomisato Miura; Naofumi Akata; Hirofumi Tazoe; Masahiro Hosoda; Kranrod Chutima; Hiromi Kudo; Koya Ogura; Yohei Fujishima; Yuki Tamakuma; Mayumi Shimizu; Kazutaka Kikuchi; Ikuo Kashiwakura. Support activities in Namie Town, Fukushima undertaken by Hirosaki University. Annals of the ICRP 2021, 1 .

AMA Style

Shinji Tokonami, Tomisato Miura, Naofumi Akata, Hirofumi Tazoe, Masahiro Hosoda, Kranrod Chutima, Hiromi Kudo, Koya Ogura, Yohei Fujishima, Yuki Tamakuma, Mayumi Shimizu, Kazutaka Kikuchi, Ikuo Kashiwakura. Support activities in Namie Town, Fukushima undertaken by Hirosaki University. Annals of the ICRP. 2021; ():1.

Chicago/Turabian Style

Shinji Tokonami; Tomisato Miura; Naofumi Akata; Hirofumi Tazoe; Masahiro Hosoda; Kranrod Chutima; Hiromi Kudo; Koya Ogura; Yohei Fujishima; Yuki Tamakuma; Mayumi Shimizu; Kazutaka Kikuchi; Ikuo Kashiwakura. 2021. "Support activities in Namie Town, Fukushima undertaken by Hirosaki University." Annals of the ICRP , no. : 1.

Journal article
Published: 04 February 2021 in International Journal of Environmental Research and Public Health
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A long-term measurement technique of radon exhalation rate was previously developed using a passive type radon and thoron discriminative monitor and a ventilated type accumulation chamber. In the present study, this technique was applied to evaluate the thoron exhalation rate as well, and long-term measurements of radon and thoron exhalation rates were conducted for four years in Gifu Prefecture. The ventilated type accumulation chamber (0.8 × 0.8 × 1.0 m3) with an open bottom was embedded 15 cm into the ground. The vertical distributions of radon and thoron activity concentrations from the ground were obtained using passive type radon-thoron discriminative monitors (RADUETs). The RADUETs were placed at 1, 3, 10, 30, and 80 cm above the ground inside the accumulation chamber. The measurements were conducted from autumn 2014 to autumn 2018. These long-term results were found to be in good agreement with the values obtained by another methodology. The radon exhalation rates from the ground showed a clearly seasonal variation. Similar to findings of previous studies, radon exhalation rates from summer to autumn were relatively higher than those from winter to spring. In contrast, thoron exhalation rates were not found to show seasonal variation.

ACS Style

Oumar Modibo; Yuki Tamakuma; Takahito Suzuki; Ryohei Yamada; Weihai Zhuo; Chutima Kranrod; Kazuki Iwaoka; Naofumi Akata; Masahiro Hosoda; Shinji Tokonami. Long-Term Measurements of Radon and Thoron Exhalation Rates from the Ground Using the Vertical Distributions of Their Activity Concentrations. International Journal of Environmental Research and Public Health 2021, 18, 1489 .

AMA Style

Oumar Modibo, Yuki Tamakuma, Takahito Suzuki, Ryohei Yamada, Weihai Zhuo, Chutima Kranrod, Kazuki Iwaoka, Naofumi Akata, Masahiro Hosoda, Shinji Tokonami. Long-Term Measurements of Radon and Thoron Exhalation Rates from the Ground Using the Vertical Distributions of Their Activity Concentrations. International Journal of Environmental Research and Public Health. 2021; 18 (4):1489.

Chicago/Turabian Style

Oumar Modibo; Yuki Tamakuma; Takahito Suzuki; Ryohei Yamada; Weihai Zhuo; Chutima Kranrod; Kazuki Iwaoka; Naofumi Akata; Masahiro Hosoda; Shinji Tokonami. 2021. "Long-Term Measurements of Radon and Thoron Exhalation Rates from the Ground Using the Vertical Distributions of Their Activity Concentrations." International Journal of Environmental Research and Public Health 18, no. 4: 1489.

Journal article
Published: 22 January 2021 in International Journal of Environmental Research and Public Health
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Ten years have elapsed since the accident at the Fukushima Daiichi Nuclear Power Plant in 2011, and the relative contribution of natural radiation is increasing in Fukushima Prefecture due to the reduced dose of artificial radiation. In order to accurately determine the effective dose of exposure to artificial radiation, it is necessary to evaluate the effective dose of natural as well as artificial components. In this study, we measured the gamma-ray pulse-height distribution over the accessible area of Namie Town, Fukushima Prefecture, and evaluated the annual effective dose of external exposure by distinguishing between natural and artificial radionuclides. The estimated median (range) of absorbed dose rates in air from artificial radionuclides as of 1 April 2020, is 133 (67–511) nGy h−1 in the evacuation order cancellation zone, and 1306 (892–2081) nGy h−1 in the difficult-to-return zone. The median annual effective doses of external exposures from natural and artificial radionuclides were found to be 0.19 and 0.40 mSv in the evacuation order cancellation zone, and 0.25 and 3.9 mSv in the difficult-to-return zone. The latest annual effective dose of external exposure discriminated into natural and artificial radionuclides is expected to be utilized for radiation risk communication.

ACS Style

Koya Ogura; Masahiro Hosoda; Yuki Tamakuma; Takahito Suzuki; Ryohei Yamada; Ryoju Negami; Takakiyo Tsujiguchi; Masaru Yamaguchi; Yoshitaka Shiroma; Kazuki Iwaoka; Naofumi Akata; Mayumi Shimizu; Ikuo Kashiwakura; Shinji Tokonami. Discriminative Measurement of Absorbed Dose Rates in Air from Natural and Artificial Radionuclides in Namie Town, Fukushima Prefecture. International Journal of Environmental Research and Public Health 2021, 18, 978 .

AMA Style

Koya Ogura, Masahiro Hosoda, Yuki Tamakuma, Takahito Suzuki, Ryohei Yamada, Ryoju Negami, Takakiyo Tsujiguchi, Masaru Yamaguchi, Yoshitaka Shiroma, Kazuki Iwaoka, Naofumi Akata, Mayumi Shimizu, Ikuo Kashiwakura, Shinji Tokonami. Discriminative Measurement of Absorbed Dose Rates in Air from Natural and Artificial Radionuclides in Namie Town, Fukushima Prefecture. International Journal of Environmental Research and Public Health. 2021; 18 (3):978.

Chicago/Turabian Style

Koya Ogura; Masahiro Hosoda; Yuki Tamakuma; Takahito Suzuki; Ryohei Yamada; Ryoju Negami; Takakiyo Tsujiguchi; Masaru Yamaguchi; Yoshitaka Shiroma; Kazuki Iwaoka; Naofumi Akata; Mayumi Shimizu; Ikuo Kashiwakura; Shinji Tokonami. 2021. "Discriminative Measurement of Absorbed Dose Rates in Air from Natural and Artificial Radionuclides in Namie Town, Fukushima Prefecture." International Journal of Environmental Research and Public Health 18, no. 3: 978.

Journal article
Published: 21 January 2021 in International Journal of Environmental Research and Public Health
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The world community has long used natural hot springs for tourist and medicinal purposes. In Indonesia, the province of West Java, which is naturally surrounded by volcanoes, is the main destination for hot spring tourism. This paper is the first report on radon measurements in tourism natural hot spring water in Indonesia as part of radiation protection for public health. The purpose of this paper is to study the contribution of radon doses from natural hot spring water and thereby facilitate radiation protection for public health. A total of 18 water samples were measured with an electrostatic collection type radon monitor (RAD7, Durridge Co., USA). The concentration of radon in natural hot spring water samples in the West Java region, Indonesia ranges from 0.26 to 31 Bq L−1. An estimate of the annual effective dose in the natural hot spring water area ranges from 0.51 to 0.71 mSv with a mean of 0.60 mSv for workers. Meanwhile, the annual effective dose for the public ranges from 0.10 to 0.14 mSv with an average of 0.12 mSv. This value is within the range of the average committed effective dose from inhalation and terrestrial radiation for the general public, 1.7 mSv annually.

ACS Style

Eka Nugraha; Masahiro Hosoda; June Mellawati; Untara Untara; Ilsa Rosianna; Yuki Tamakuma; Oumar Modibo; Chutima Kranrod; Kusdiana Kusdiana; Shinji Tokonami. Radon Activity Concentrations in Natural Hot Spring Water: Dose Assessment and Health Perspective. International Journal of Environmental Research and Public Health 2021, 18, 920 .

AMA Style

Eka Nugraha, Masahiro Hosoda, June Mellawati, Untara Untara, Ilsa Rosianna, Yuki Tamakuma, Oumar Modibo, Chutima Kranrod, Kusdiana Kusdiana, Shinji Tokonami. Radon Activity Concentrations in Natural Hot Spring Water: Dose Assessment and Health Perspective. International Journal of Environmental Research and Public Health. 2021; 18 (3):920.

Chicago/Turabian Style

Eka Nugraha; Masahiro Hosoda; June Mellawati; Untara Untara; Ilsa Rosianna; Yuki Tamakuma; Oumar Modibo; Chutima Kranrod; Kusdiana Kusdiana; Shinji Tokonami. 2021. "Radon Activity Concentrations in Natural Hot Spring Water: Dose Assessment and Health Perspective." International Journal of Environmental Research and Public Health 18, no. 3: 920.

Review
Published: 25 November 2020 in International Journal of Environmental Research and Public Health
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The present paper outlines characteristics of thoron and its progeny in the indoor environment. Since the half-life of thoron (220Rn) is very short (55.6 s), its behavior is quite different from the isotope radon (222Rn, half-life 3.8 days) in the environment. Analyses of radon and lung cancer risk have revealed a clearly positive relationship in epidemiological studies among miners and residents. However, there is no epidemiological evidence for thoron exposure causing lung cancer risk. In contrast to this, a dosimetric approach has been approved in the International Commission on Radiological Protection (ICRP) Publication 137, from which new dose conversion factors for radon and thoron progenies can be obtained. They are given as 16.8 and 107 nSv (Bq m−3 h)−1, respectively. It implies that even a small quantity of thoron progeny will induce higher radiation exposure compared to radon. Thus, an interest in thoron exposure is increasing among the relevant scientific communities. As measurement technologies for thoron and its progeny have been developed, they are now readily available. This paper reviews measurement technologies, activity levels, dosimetry and resulting doses. Although thoron has been underestimated in the past, recent findings have revealed that reassessment of risks due to radon exposure may need to take the presence of thoron and its progeny into account.

ACS Style

Shinji Tokonami. Characteristics of Thoron (220Rn) and Its Progeny in the Indoor Environment. International Journal of Environmental Research and Public Health 2020, 17, 8769 .

AMA Style

Shinji Tokonami. Characteristics of Thoron (220Rn) and Its Progeny in the Indoor Environment. International Journal of Environmental Research and Public Health. 2020; 17 (23):8769.

Chicago/Turabian Style

Shinji Tokonami. 2020. "Characteristics of Thoron (220Rn) and Its Progeny in the Indoor Environment." International Journal of Environmental Research and Public Health 17, no. 23: 8769.

Journal article
Published: 18 November 2020 in International Journal of Environmental Research and Public Health
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An improved passive CR-39-based direct 222Rn/220Rn progeny detector with 3 detection channels was designed and tested in this study to measure and calculate equilibrium equivalent concentration (EEC) of both 222Rn and 220Rn without the equilibrium factor. A theoretical model was established to calculate the EEC with optimization. Subsequently, an exposure experiment was carried out to test the performance of this detector, and we compared the chamber experiment and the theoretical model by estimating and measuring various parameters. The deposition flux of progeny derived from the prediction agreed well with the value measured in the exposure chamber. The energy-weighted net track density (NTD) measured by this detector is much more reliable to reflect the linear relation between NTD and time-integrated EEC. Since the detector is sensitive to the exposure environmental condition, it is recommended to apply the detector to measure the EEC after its calibration in a typical indoor environment.

ACS Style

Jun Hu; Guosheng Yang; Chutima Kranrod; Kazuki Iwaoka; Masahiro Hosoda; Shinji Tokonami. An Improved Passive CR-39-Based Direct 222Rn/220Rn Progeny Detector. International Journal of Environmental Research and Public Health 2020, 17, 1 .

AMA Style

Jun Hu, Guosheng Yang, Chutima Kranrod, Kazuki Iwaoka, Masahiro Hosoda, Shinji Tokonami. An Improved Passive CR-39-Based Direct 222Rn/220Rn Progeny Detector. International Journal of Environmental Research and Public Health. 2020; 17 (22):1.

Chicago/Turabian Style

Jun Hu; Guosheng Yang; Chutima Kranrod; Kazuki Iwaoka; Masahiro Hosoda; Shinji Tokonami. 2020. "An Improved Passive CR-39-Based Direct 222Rn/220Rn Progeny Detector." International Journal of Environmental Research and Public Health 17, no. 22: 1.

Journal article
Published: 19 September 2020 in Geosciences
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Mamuju is a region of Indonesia with relatively high exposure to natural radiation. Since 2012, Mamuju has been a uranium and thorium exploration area. Several mapping studies of the region have been carried out to depict NORM (naturally occurring radioactive material) areas and areas with uranium anomalies. This paper is the first study to use radioactivity measurements of laterite and volcanic rocks to determine the characteristics of radionuclides and other mineral measurements, which are essential for categorising Mamuju rocks and exploring the region as a potential mining area. The radioactivity of the samples was measured using a high-purity germanium (HPGe) detector. Furthermore, we used X-ray fluorescence (XRF) to determine the rock mineral composition. Mamuju is anomalous due to its high content of 238U and 232Th concentrations of 539–128,699 Bq·kg−1 (average: 22,882 Bq·kg−1) and 471–288,639 Bq·kg−1 (average: 33,549 Bq·kg−1), respectively. The major elements are dominant, including Fe2O3, SiO2, Al2O3, and Na2O, with several other major elements such as MnO, TiO2, and CaO.

ACS Style

Ilsa Rosianna; Eka Nugraha; Heri Syaeful; Sugili Putra; Masahiro Hosoda; Naofumi Akata; Shinji Tokonami. Natural Radioactivity of Laterite and Volcanic Rock Sample for Radioactive Mineral Exploration in Mamuju, Indonesia. Geosciences 2020, 10, 376 .

AMA Style

Ilsa Rosianna, Eka Nugraha, Heri Syaeful, Sugili Putra, Masahiro Hosoda, Naofumi Akata, Shinji Tokonami. Natural Radioactivity of Laterite and Volcanic Rock Sample for Radioactive Mineral Exploration in Mamuju, Indonesia. Geosciences. 2020; 10 (9):376.

Chicago/Turabian Style

Ilsa Rosianna; Eka Nugraha; Heri Syaeful; Sugili Putra; Masahiro Hosoda; Naofumi Akata; Shinji Tokonami. 2020. "Natural Radioactivity of Laterite and Volcanic Rock Sample for Radioactive Mineral Exploration in Mamuju, Indonesia." Geosciences 10, no. 9: 376.

Journal article
Published: 15 September 2020 in Science of The Total Environment
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The biological effects of low dose-rate radiation exposures on humans remains unknown. In fact, the Japanese nation still struggles with this issue after the Fukushima Dai-ichi Nuclear Power Plant accident. Recently, we have found a unique area in Indonesia where naturally high radiation levels are present, resulting in chronic low dose-rate radiation exposures. We aimed to estimate the comprehensive dose due to internal and external exposures at the particularly high natural radiation area, and to discuss the enhancement mechanism of radon. A car-borne survey was conducted to estimate the external doses from terrestrial radiation. Indoor radon measurements were made in 47 dwellings over three to five months, covering the two typical seasons, to estimate the internal doses. Atmospheric radon gases were simultaneously collected at several heights to evaluate the vertical distribution. The absorbed dose rates in air in the study area vary widely between 50 nGy h−1 and 1109 nGy h−1. Indoor radon concentrations ranged from 124 Bq m−3 to 1015 Bq m−3. That is, the indoor radon concentrations measured exceed the reference levels of 100 Bq m−3 recommended by the World Health Organization. Furthermore, the outdoor radon concentrations measured were comparable to the high indoor radon concentrations. The annual effective dose due to external and internal exposures in the study area was estimated to be 27 mSv using the median values. It was found that many residents are receiving radiation exposure from natural radionuclides over the dose limit for occupational exposure to radiation workers. This enhanced outdoor radon concentration might be as a result of the stable atmospheric conditions generated at an exceptionally low altitude. Our findings suggest that this area provides a unique opportunity to conduct an epidemiological study related to health effects due to chronic low dose-rate radiation exposure.

ACS Style

Masahiro Hosoda; Eka Djatnika Nugraha; Naofumi Akata; Ryohei Yamada; Yuki Tamakuma; Michiya Sasaki; Kevin Kelleher; Shinji Yoshinaga; Takahito Suzuki; Chanis Pornnumpa Rattanapongs; Masahide Furukawa; Masaru Yamaguchi; Kazuki Iwaoka; Tetsuya Sanada; Tomisato Miura; Kusdiana; Dadong Iskandar; Eko Pudjadi; Ikuo Kashiwakura; Shinji Tokonami. A unique high natural background radiation area – Dose assessment and perspectives. Science of The Total Environment 2020, 750, 142346 .

AMA Style

Masahiro Hosoda, Eka Djatnika Nugraha, Naofumi Akata, Ryohei Yamada, Yuki Tamakuma, Michiya Sasaki, Kevin Kelleher, Shinji Yoshinaga, Takahito Suzuki, Chanis Pornnumpa Rattanapongs, Masahide Furukawa, Masaru Yamaguchi, Kazuki Iwaoka, Tetsuya Sanada, Tomisato Miura, Kusdiana, Dadong Iskandar, Eko Pudjadi, Ikuo Kashiwakura, Shinji Tokonami. A unique high natural background radiation area – Dose assessment and perspectives. Science of The Total Environment. 2020; 750 ():142346.

Chicago/Turabian Style

Masahiro Hosoda; Eka Djatnika Nugraha; Naofumi Akata; Ryohei Yamada; Yuki Tamakuma; Michiya Sasaki; Kevin Kelleher; Shinji Yoshinaga; Takahito Suzuki; Chanis Pornnumpa Rattanapongs; Masahide Furukawa; Masaru Yamaguchi; Kazuki Iwaoka; Tetsuya Sanada; Tomisato Miura; Kusdiana; Dadong Iskandar; Eko Pudjadi; Ikuo Kashiwakura; Shinji Tokonami. 2020. "A unique high natural background radiation area – Dose assessment and perspectives." Science of The Total Environment 750, no. : 142346.

Journal article
Published: 05 August 2020 in International Journal of Environmental Research and Public Health
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The International Commission on Radiological Protection (ICRP) recently recommended a new dose conversion factor for radon based on the latest epidemiological studies and dosimetric model. It is important to evaluate an inhalation dose from radon and its progeny. In the present study, a passive radon personal monitor was designed using a small container for storing contact lenses and its performance was evaluated. The conversion factor for radon (222Rn), the effect of thoron (220Rn) concentration and the air exchange rate were evaluated using the calibration chamber at Hirosaki University. The minimum and maximum detectable radon concentrations were calculated. The conversion factor was evaluated as 2.0 ± 0.3 tracks cm−2 per kBq h m−3; statistical analyses of results showed no significant effect from thoron concentration. The minimum and maximum detectable radon concentrations were 92 Bq m−3 and 231 kBq m−3 for a measurement period of three months, respectively. The air exchange rate was estimated to be 0.26 ± 0.16 h−1, whose effect on the measured time-integrated radon concentration was small. These results indicate that the monitor could be used as a wearable monitor for radon measurements, especially in places where radon concentrations may be relatively high, such as mines and caves.

ACS Style

Yuki Tamakuma; Chutima Kranrod; Takahito Suzuki; Yuki Watanabe; Thamaborn Ploykrathok; Ryoju Negami; Eka Djatnika Nugraha; Kazuki Iwaoka; Mirosław Janik; Masahiro Hosoda; Shinji Tokonami. Passive-Type Radon Monitor Constructed Using a Small Container for Personal Dosimetry. International Journal of Environmental Research and Public Health 2020, 17, 5660 .

AMA Style

Yuki Tamakuma, Chutima Kranrod, Takahito Suzuki, Yuki Watanabe, Thamaborn Ploykrathok, Ryoju Negami, Eka Djatnika Nugraha, Kazuki Iwaoka, Mirosław Janik, Masahiro Hosoda, Shinji Tokonami. Passive-Type Radon Monitor Constructed Using a Small Container for Personal Dosimetry. International Journal of Environmental Research and Public Health. 2020; 17 (16):5660.

Chicago/Turabian Style

Yuki Tamakuma; Chutima Kranrod; Takahito Suzuki; Yuki Watanabe; Thamaborn Ploykrathok; Ryoju Negami; Eka Djatnika Nugraha; Kazuki Iwaoka; Mirosław Janik; Masahiro Hosoda; Shinji Tokonami. 2020. "Passive-Type Radon Monitor Constructed Using a Small Container for Personal Dosimetry." International Journal of Environmental Research and Public Health 17, no. 16: 5660.

Journal article
Published: 11 July 2020 in International Journal of Environmental Research and Public Health
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Activity concentrations of 234U, 235U, 238U, 226Ra, 228Ra, 222Rn, 210Po, 210Pb, 40K, 3H, 14C, 134Cs and 137Cs were determined in 20 different Japanese bottled drinking water commercially available in Japan. The origins of the mineral water samples were geographically distributed across different regions of Japan. Activity concentrations above detection limits were measured for the radionuclides 234U, 235U, 238U, 226Ra, 228Ra and 210Po. An average total annual effective dose due to ingestion was estimated for adults, based on the average annual volume of bottled water consumed in Japan in 2019, reported to be 31.7 L/y per capita. The estimated dose was found to be below the recommended World Health Organisation (WHO) guidance level of 0.1 mSv/y for drinking water quality. The most significant contributor to the estimated dose was 228Ra.

ACS Style

Aoife Kinahan; Masahiro Hosoda; Kevin Kelleher; Takakiyo Tsujiguchi; Naofumi Akata; Shinji Tokonami; Lorraine Currivan; Luis Leon Vintro. Assessment of Radiation Dose from the Consumption of Bottled Drinking Water in Japan. International Journal of Environmental Research and Public Health 2020, 17, 4992 .

AMA Style

Aoife Kinahan, Masahiro Hosoda, Kevin Kelleher, Takakiyo Tsujiguchi, Naofumi Akata, Shinji Tokonami, Lorraine Currivan, Luis Leon Vintro. Assessment of Radiation Dose from the Consumption of Bottled Drinking Water in Japan. International Journal of Environmental Research and Public Health. 2020; 17 (14):4992.

Chicago/Turabian Style

Aoife Kinahan; Masahiro Hosoda; Kevin Kelleher; Takakiyo Tsujiguchi; Naofumi Akata; Shinji Tokonami; Lorraine Currivan; Luis Leon Vintro. 2020. "Assessment of Radiation Dose from the Consumption of Bottled Drinking Water in Japan." International Journal of Environmental Research and Public Health 17, no. 14: 4992.

Review
Published: 10 June 2020 in International Journal of Environmental Research and Public Health
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Radon (222Rn) and thoron (220Rn), sources of natural background radiation, have been the subjects of long-standing studies, including research into radon and thoron as major causes of lung cancer at domestic and international levels. In this regard, radon and thoron measurement studies have been widely conducted all over the world. Generally, the techniques used relate to passive nuclear track detectors. Some surveys have shown that passive monitors for radon are sensitive to thoron, and hence some measured results have probably overestimated radon concentrations. This study investigated radon and thoron measurements in domestic and international surveys using the passive radon–thoron discriminative monitor, commercially named RADUET. This paper attempts to provide an understanding of discriminative measurements of radon isotopes and to present an evidence-based roadmap.

ACS Style

Chutima Kranrod; Yuki Tamakuma; Masahiro Hosoda; Shinji Tokonami. Importance of Discriminative Measurement for Radon Isotopes and Its Utilization in the Environment and Lessons Learned from Using the RADUET Monitor. International Journal of Environmental Research and Public Health 2020, 17, 1 .

AMA Style

Chutima Kranrod, Yuki Tamakuma, Masahiro Hosoda, Shinji Tokonami. Importance of Discriminative Measurement for Radon Isotopes and Its Utilization in the Environment and Lessons Learned from Using the RADUET Monitor. International Journal of Environmental Research and Public Health. 2020; 17 (11):1.

Chicago/Turabian Style

Chutima Kranrod; Yuki Tamakuma; Masahiro Hosoda; Shinji Tokonami. 2020. "Importance of Discriminative Measurement for Radon Isotopes and Its Utilization in the Environment and Lessons Learned from Using the RADUET Monitor." International Journal of Environmental Research and Public Health 17, no. 11: 1.

Journal article
Published: 29 May 2020 in Nukleonika
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The exposure from radon, thoron, and thoron progeny was measured for 45 dwellings in high background radiation area in Takandeang, Indonesia with ambient dose equivalent rate ranging from 0.34 μSv h−1 to 1.90 μSv h−1. The measurement was taken using passive radon and thoron discriminative detector and thoron progeny detector. This measurement was taken from November 2018 to October 2019, and within one month the detector would be replaced with a new detector. The concentrations of radon, thoron, and thoron progeny were calculated as 42–490 Bq m−3, 20–618 Bq m−3, and 4–40 Bq m−3, respectively. The concentrations for outdoor were 49–435 Bq m−3, 23–457 Bq m−3, and 4–37 Bq m−3, respectively, and the annual effective dose was 9.8–28.6 mSv y−1. Based on the result of Spearman’s correlations analysis between the indoor radon and thoron concentrations and between the indoor thoron progeny and thoron concentrations, we suggest that exposure to thoron cannot be predicted from exposure to radon, and the equilibrium equivalent thoron concentration has a large uncertainty when it is estimated from thoron concentration assuming a single thoron equilibrium factor.

ACS Style

Miki Arian Saputra; Eka Djatnika Nugraha; Tri Purwanti; Rokhmat Arifianto; Roza Indra Laksmana; Richard P. Hutabarat; Masahiro Hosoda; Shinji Tokonami. Exposures from radon, thoron, and thoron progeny in high background radiation area in Takandeang, Mamuju, Indonesia. Nukleonika 2020, 65, 89 -94.

AMA Style

Miki Arian Saputra, Eka Djatnika Nugraha, Tri Purwanti, Rokhmat Arifianto, Roza Indra Laksmana, Richard P. Hutabarat, Masahiro Hosoda, Shinji Tokonami. Exposures from radon, thoron, and thoron progeny in high background radiation area in Takandeang, Mamuju, Indonesia. Nukleonika. 2020; 65 (2):89-94.

Chicago/Turabian Style

Miki Arian Saputra; Eka Djatnika Nugraha; Tri Purwanti; Rokhmat Arifianto; Roza Indra Laksmana; Richard P. Hutabarat; Masahiro Hosoda; Shinji Tokonami. 2020. "Exposures from radon, thoron, and thoron progeny in high background radiation area in Takandeang, Mamuju, Indonesia." Nukleonika 65, no. 2: 89-94.

Journal article
Published: 29 May 2020 in Nukleonika
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The deposition-based direct indoor 222Rn and 220Rn progeny measurement techniques are mostly affected by the indoor environmental conditions, such as the ventilation, concentration of condensation nuclei, and reactions with the structure and its furnishings. In this study, a theoretical model of a direct 222Rn and 220Rn progeny monitor based on allyl diglycol carbonate (ADC or CR-39) was established to analyse the factors that influence the detection process by using the parameter sensitivity analysis. The aerosol parameters contributed the highest to the variance, followed by the aerodynamic parameters. With respect to the result of the Spearman’s correlation analysis, the aerosol-related and the room-related parameters are positive, whereas the aerodynamic parameters – which affect the turbulence of indoor deposition – are negative. It means that both the attachment process and the deposition process of 222Rn and 220Rn progenies are important to the performance of the progeny monitor.

ACS Style

Jun Hu; Masahiro Hosoda; Shinji Tokonami. Parameter sensitivity analysis of the theoretical model of a CR-39-based direct 222Rn/220Rn progeny monitor. Nukleonika 2020, 65, 95 -98.

AMA Style

Jun Hu, Masahiro Hosoda, Shinji Tokonami. Parameter sensitivity analysis of the theoretical model of a CR-39-based direct 222Rn/220Rn progeny monitor. Nukleonika. 2020; 65 (2):95-98.

Chicago/Turabian Style

Jun Hu; Masahiro Hosoda; Shinji Tokonami. 2020. "Parameter sensitivity analysis of the theoretical model of a CR-39-based direct 222Rn/220Rn progeny monitor." Nukleonika 65, no. 2: 95-98.

Journal article
Published: 02 May 2020 in International Journal of Environmental Research and Public Health
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Air exchange through a porous medium depends partly on a pressure gradient induced in it, i.e., air-flow conditions of the outer air. Consequently, response of diffusion-type detectors to radon and thoron may vary with air-flow conditions surrounding the detectors. This effect may be significant for thoron measurement because thoron has a shorter half-life than radon. The present study examined response of diffusion-type detectors (RADUETs and one AlphaGUARD) to thoron with respect to wind speed using a thoron calibration chamber. Response of RADUETs to thoron increased with wind speed. Response of the AlphaGUARD increased with wind speed, but it became constant at a high wind speed. Different response trends to thoron between the RADUETs and the AlphaGUARD could be qualitatively explained by flow states induced by the pressure gradient in the filter or the sponge of these detectors. For RADUETs, laminar (Darcy) flow was induced in the sponge in the examined wind speed range, which meant that thoron entry into the detector increased with wind speed. For the AlphaGUARD, laminar flow was induced in the filter in the low wind speed range, whereas flow was changed to turbulent (non-Darcy) flow at a high wind speed for which thoron entry into the detector did not depend on wind speed.

ACS Style

Yasutaka Omori; Yuki Tamakuma; Eka Djatnika Nugraha; Takahito Suzuki; Miki Arian Saputra; Masahiro Hosoda; Shinji Tokonami. Impact of Wind Speed on Response of Diffusion-Type Radon-Thoron Detectors to Thoron. International Journal of Environmental Research and Public Health 2020, 17, 3178 .

AMA Style

Yasutaka Omori, Yuki Tamakuma, Eka Djatnika Nugraha, Takahito Suzuki, Miki Arian Saputra, Masahiro Hosoda, Shinji Tokonami. Impact of Wind Speed on Response of Diffusion-Type Radon-Thoron Detectors to Thoron. International Journal of Environmental Research and Public Health. 2020; 17 (9):3178.

Chicago/Turabian Style

Yasutaka Omori; Yuki Tamakuma; Eka Djatnika Nugraha; Takahito Suzuki; Miki Arian Saputra; Masahiro Hosoda; Shinji Tokonami. 2020. "Impact of Wind Speed on Response of Diffusion-Type Radon-Thoron Detectors to Thoron." International Journal of Environmental Research and Public Health 17, no. 9: 3178.

Journal article
Published: 10 December 2019 in International Journal of Environmental Research and Public Health
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Comparison is an important role in the quality control and quality assurance for any measuring system. Due to the future legal regulations regarding radon levels in the air, maintaining the system quality and harmonization of results as well as validation of radon and thoron measuring systems is important. The aim of this work is to validate the degrees of equivalence and measurement precisions of the existing five radon and four thoron measuring systems located in four Asian countries (China, India, Japan and Thailand) through comparison experiment. In this project, comparison experiment was performed in order to derive the ratio between assigned value obtained from one transfer measurement device for radon and one transfer measurement device for thoron belongs to National Institutes for Quantum and Radiological Science and Technology and participants’ value from their measuring instrument. As a result, the ratio value associated with measurement uncertainty was derived for each activity concentration. Finally, measurement bias and degrees of equivalence between the assigned values and values of measurement quantity from participants’ measuring instruments were statistically analysed and presented.

ACS Style

Miroslaw Janik; Shinji Tokonami; Kazuki Iwaoka; Naregundi Karunakara; Shetty Trilochana; Mandya Purushotham Mohan; Sudeep Kumara; Indaje Yashodhara; Weihai Zhuo; Chao Zhao; Fangdong Tang; Linfeng He; Supitcha Chanyotha; Chutima Kranrod; Darwish Al-Azmi; Osamu Kurihara. Comparison of Radon and Thoron Concentration Measuring Systems Among Asian Countries. International Journal of Environmental Research and Public Health 2019, 16, 5019 .

AMA Style

Miroslaw Janik, Shinji Tokonami, Kazuki Iwaoka, Naregundi Karunakara, Shetty Trilochana, Mandya Purushotham Mohan, Sudeep Kumara, Indaje Yashodhara, Weihai Zhuo, Chao Zhao, Fangdong Tang, Linfeng He, Supitcha Chanyotha, Chutima Kranrod, Darwish Al-Azmi, Osamu Kurihara. Comparison of Radon and Thoron Concentration Measuring Systems Among Asian Countries. International Journal of Environmental Research and Public Health. 2019; 16 (24):5019.

Chicago/Turabian Style

Miroslaw Janik; Shinji Tokonami; Kazuki Iwaoka; Naregundi Karunakara; Shetty Trilochana; Mandya Purushotham Mohan; Sudeep Kumara; Indaje Yashodhara; Weihai Zhuo; Chao Zhao; Fangdong Tang; Linfeng He; Supitcha Chanyotha; Chutima Kranrod; Darwish Al-Azmi; Osamu Kurihara. 2019. "Comparison of Radon and Thoron Concentration Measuring Systems Among Asian Countries." International Journal of Environmental Research and Public Health 16, no. 24: 5019.

Article
Published: 21 November 2019 in Journal of Radioanalytical and Nuclear Chemistry
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The radioactivity of cesium in the water and sediments of two major rivers was measured along with airborne radioactivity in Namie Town, after the recent partial lift on the evacuation order in 2017. The observed concentrations were up to 384 ± 11 mBq/L for 137Cs in unfiltered water and 1.28 ± 0.09 mBq m−3 for 137Cs in air, while the sediment had a maximum of 44,900 ± 23 Bq kg−1 for 137Cs. The potential yearly committed effective dose was estimated based on the data.

ACS Style

M. Hegedűs; Y. Shiroma; K. Iwaoka; M. Hosoda; T. Suzuki; Y. Tamakuma; R. Yamada; T. Tsujiguchi; M. Yamaguchi; K. Ogura; H. Tazoe; N. Akata; I. Kashiwakura; S. Tokonami. Cesium concentrations in various environmental media at Namie, Fukushima. Journal of Radioanalytical and Nuclear Chemistry 2019, 323, 197 -204.

AMA Style

M. Hegedűs, Y. Shiroma, K. Iwaoka, M. Hosoda, T. Suzuki, Y. Tamakuma, R. Yamada, T. Tsujiguchi, M. Yamaguchi, K. Ogura, H. Tazoe, N. Akata, I. Kashiwakura, S. Tokonami. Cesium concentrations in various environmental media at Namie, Fukushima. Journal of Radioanalytical and Nuclear Chemistry. 2019; 323 (1):197-204.

Chicago/Turabian Style

M. Hegedűs; Y. Shiroma; K. Iwaoka; M. Hosoda; T. Suzuki; Y. Tamakuma; R. Yamada; T. Tsujiguchi; M. Yamaguchi; K. Ogura; H. Tazoe; N. Akata; I. Kashiwakura; S. Tokonami. 2019. "Cesium concentrations in various environmental media at Namie, Fukushima." Journal of Radioanalytical and Nuclear Chemistry 323, no. 1: 197-204.