A5001653063- Radioactivity and Radon Measurements
- Radioactive contamination and transfer
- Nuclear and radioactivity studies
- Radiation Dose and Imaging
- Radiation Detection and Scintillator Technologies
- Graphite, nuclear technology, radiation studies
- Nuclear Physics and Applications
- Radioactive element chemistry and processing
- Radiation Shielding Materials Analysis
- Geophysical Methods and Applications
- Geochemistry and Geologic Mapping
- Risk Perception and Management
- Earthquake Detection and Analysis
- Effects of Radiation Exposure
- Medical Imaging Techniques and Applications
- Radiation Therapy and Dosimetry
- Radioactive Decay and Measurement Techniques
- Air Quality and Health Impacts
- Heavy metals in environment
- Air Quality Monitoring and Forecasting
- Health, Environment, Cognitive Aging
- Advances in Oncology and Radiotherapy
- Groundwater and Isotope Geochemistry
- Risk and Safety Analysis
- Nuclear reactor physics and engineering
Hirosaki University
2016-2025
National Nuclear Energy Agency of Indonesia
2023
National Research and Innovation Agency
2023
National Institutes for Quantum Science and Technology
2004-2019
Japan Atomic Energy Agency
2016-2019
Osaka Prefecture University
2006-2018
The University of Tokyo
2017
Fukushima Medical University
2016
Université de Yaoundé I
2015
Institut de Recherches Géologiques et Minières
2015
An up-to-date radon-thoron discriminative detector has been developed for conducting a large scale survey. Comparing with our previous detector, some functional problems have solved. The lowest and highest detection limits of the were estimated to be around 5 1000Bqm−3 radon, 15 thoron, respectively, 6month exposure several theoretical assumptions. Small indoor survey carried out in Japan Hungary using present detector. presence thoron was demonstrated any surveys by two results. Since...
A primary health concern among residents and evacuees in affected areas immediately after a nuclear accident is the internal exposure of thyroid to radioiodine, particularly I-131, subsequent cancer risk. In Japan, natural disasters earthquake tsunami March 2011 destroyed an important function Fukushima Daiichi Nuclear Power Plant (F1-NPP) large amount radioactive material was released environment. Here we report for first time extensive measurements I-131 revealing activity 46 out 62...
Abstract The annual exposure to indoor radon, thoron and their progeny imparts a major contribution inhalation doses received by the public. In this study, we report results of time integrated passive measurements concentrations that were carried out in Garhwal Himalaya with aim investigating significant health risk dwellers region. performed using recently developed LR-115 detector based techniques. experimentally determined values used estimate total dose effective doses. equilibrium...
Abstract The radioactive fission product 90 Sr has a long biological half-life (˜18 y) in the human body. Due to its chemical similarity calcium it accumulates bones and irradiates bone marrow, causing high radio-toxicity. Assessing is therefore extremely important case of nuclear disaster. In this work 16 soil samples were collected from exclusion zone (<30 km) earthquake-damaged Fukushima Daiichi power plant, measure activity concentration using liquid scintillation counting. 137 Cs was...
New scientific findings based on the latest epidemiological analyses for lung cancer risk due to radon have been demonstrated. The residential concentration is mainly measured by passive detectors. Although detector usually designed detect efficiently and exclusively, several types of them can thoron together with radon. In this case, these readings may include both signals. If are overestimated, will be given as a biased estimate when studies carried out. our experience, there seem no...
The present study aimed to evaluate the effects of high background radiation (HBR) on mortality. A cohort 31,604 men and women aged 30–74 y living in area Guangdong Province, China, was followed during period 1979–1998. information deaths migrations members collected by visiting areas every 3–4 y. Cumulative external dose, lagged 2 for leukemia 10 cancer excluding leukemia, estimated each individual based hamlet-specific indoor outdoor doses, gender- age-specific house occupancy factors....
A car-borne survey for dose rate in air was carried out March and April 2011 along an expressway passing northwest of the Fukushima Dai-ichi Nuclear Power Station which released radionuclides starting after Great East Japan Earthquake on 11, area closer to NPS is known have been strongly affected. Dose rates expressway, i.e. relatively far from power station were higher than before some places by several orders magnitude, implying that there additional releases NPS. The maximum within high...
Radon (222Rn), a radioactive and gaseous progeny of Uranium (238U) decay series, accounts for almost 50% the total background radiation in our dwelling environment. Inhalation ingestion radon excessive amounts pose serious health effects to humans. The first-ever measurement concentration commercial bottled water available Dhaka city deep well samples from campus University was carried out using RAD7 monitoring system. ranged 0.11 Bq/L 1.30 with mean 0.59 Bq/L, showed 4.88 range 3.02 5.98...
Measurements of natural radiation were carried out in cave dwellings distributed the Chinese loess plateau. Those are located Shanxi and Shaanxi provinces. Radon thoron gas concentrations measured using a passive integrating radon-thoron discriminative detector. Concentrations decay products estimated from measurements their deposition rates. A detector was placed at center each dwelling for 6 months replaced with fresh one another months. conducted 202 August 2001 through 2002. short-term...
Radon (222Rn) generated within the grains of rocks, soils, building materials and other by radioactive decay radium (226Ra) can migrate to atmosphere. This paper reviews emanation coefficient, diffusion exhalation rate, factors that control rate at which radon enter The coefficient is fraction escaped pore space, varied from 2.1 32% for 0.14 80% soil, 0.10 58% in case materials. In addition, measurement methods used evaluate its influence are also reviewed. a process determined concentration...
Abstract. Anomalous emanation of radon (222Rn) was observed preceding large earthquakes and is considered to be linked preseismic electromagnetic phenomena (e.g. great changes atmospheric electric field ionospheric disturbances). Here we analyze concentration estimate electrical conditions in atmosphere due anomaly. The increase obeys crustal damage evolution, following a power-law time-to-earthquake. Moreover, the decreases by 40%, besides influencing maximum strength 104–105 V/m enough...
Radionuclide concentrations in environmental samples such as surface soils, plants and water were evaluated by high purity germanium detector measurements. The contribution rate of short half-life radionuclides 132I to the exposure dose residents was discussed from measured values. highest values 131I/137Cs activity ratio ranged 49 70 collected at Iwaki City which is located south F1-NPS. On other hand, 132I/131I same had lowest values, ranging 0.01 0.02. By assuming that atmosphere equal...
The present study focuses on internal exposure caused by the inhalation of radon and thoron progenies because exposures have not yet been clarified. For their dose assessment, radon, progeny concentrations were measured passive monitors over a long period (for 6 months). Consequently, equilibrium equivalent given as 124 ± 78, 1247 1189 7.8 9.1 Bq m−3, respectively. Annual effective doses are estimated to be 3.1 2.0 mSv for 2.2 2.5 thoron. Total 5.3 3.5 a−1. has revealed that was comparable...
Radon (Rn), thoron (Tn) and progeny (TnP) were measured in seven inhabited areas of the uranium thorium bearing region Lolodorf, located southwestern Cameroon. Then equilibrium factor (FTn) between its was determined order to show importance direct measurements for correct estimation effective dose due radon, their progenies. A total 220 RADUET detectors used measure indoor radon 130 TnP monitors indoors. The arithmetic geometric mean concentrations Rn, Tn 103 89 Bq m-3, 173 118 10.7 7.4 m-3...
Abstract Mamuju is one of the regions in Indonesia which retains natural conditions but has relatively high exposure to radiation. The goals present study were characterize entire region as a background radiation area (HNBRA) and assess existing means for protection public environment. A cross-sectional method was used with cluster sampling areas by measuring all parameters that contribute external internal exposures. It determined unique HNBRA annual effective dose between 17 115 mSv, an...
Abstract In this study, the activity concentrations of radon (222Rn), thoron (220Rn) and progeny were measured simultaneously in Djeno (Pointe-Noire, Republic Congo) using RADUET detectors to evaluate air quality radiological risks due inhalation these radionuclides. Activity calculated from those radon. Indoor radon, progenies followed a lognormal distribution ranging between 20 40, 6 62, 8 17.6 0.4 19.6 Bq m−3 for thoron, progeny, respectively. Mean values lower than worldwide estimated by...
Chiang Mai province of Thailand is known for having the highest natural background radiation in country, as well being recognized one world’s most polluted cities air quality. This represents major contributor to development lung cancer. research aims estimate comprehensive dose both internal and external exposure due related health perspectives highly area Mai. The average values indoor radon thoron concentrations 99 houses over 6 months were 40.8 ± 22.6 17.8 16.3 Bq/m3, respectively. These...
A simple passive monitor was developed for integrating measurements of indoor thoron concentrations. The remodeled from a commercially available radon with allyl diglycol carbonate (CR-39) detector. By adding four holes (φ=12 mm) and covering them high permeability filter paper, the air exchange rate largely enhanced. technical characteristics both monitors were examined through calibration experiments. conversion factor 1.32±0.14 tracks cm−2⋅(kBq m−3 h−1)−1 low lower detection limit provide...