Analysis of Contour Map of Natural Radiation in Japan

Fujitaka, Kazunobu; Abe, Siro; Fujimoto, Kenzo

doi:10.1080/18811248.1981.9733311

Cited by 5 publications

(4 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For that, these pathways, which are less than 4 m wide, more closely resemble streets than roads and are situated within residential and mountainous areas. Therefore, the recorded values exhibit major variation contingent upon the nature of the surrounding land uses [ 25 ]. This variation indicates the natural attenuation occurring in the vicinity of pathways, which are readily accessible to the public.…”

Section: Resultsmentioning

confidence: 99%

Low-Cost Sensor Deployment on a Public Minibus in Fukushima Prefecture

Omega,

Ishigaki,

Permana

et al. 2024

Sensors

View full text Add to dashboard Cite

This study analyzed radiation dose data to observe the annual decline in ambient radiation doses and assess the factors contributing to fluctuations in reconstructed areas of the Fukushima prefecture. Utilizing a novel mobile monitoring system installed on a community minibus, the study employed a cost-effective sensor, namely, Pocket Geiger which was integrated with a microcontroller and telecommunication system for data transfer, access, visualization, and accumulation. The study area included the region between Okuma and Tomioka towns. The ambient dose rate recorded along the minibus route was depicted on a map, averaged within a 1 × 1 km mesh created with the Quantum Geographic Information System. To ensure accuracy, the shielding factor of the minibus material is determined to adjust the dose readings. A significant decrease (p < 0.001) in the radiation dose ranges from 2022 to 2023 was observed. The land use classification by the Advanced Land Observation Satellite revealed an ecological half-life ranging from 2.41 years to 1 year, suggesting a rapid radiation decay across all land types. This underscores the close connection between radiation attenuation and environmental factors, as well as decontamination efforts across diverse land categories.

show abstract

Section: Resultsmentioning

confidence: 99%

Low-Cost Sensor Deployment on a Public Minibus in Fukushima Prefecture

Omega,

Ishigaki,

Permana

et al. 2024

Sensors

View full text Add to dashboard Cite

show abstract

“…Radon and thoron are chemically inert and electrically uncharged natural gaseous radioactive nuclides. They are released out of rocks and soil and spontaneously decay to other metal nuclides [1][2][3][4][5][6], which are the main sources of internal exposure. The indoor and outdoor concentrations of these nuclides vary significantly with the ventilating conditions, as well as seasonal changes and regional differences.…”

Section: Introductionmentioning

confidence: 99%

Effect of spring water on the radon concentration in the air at Masutomi spa in Yamanashi Prefecture, Japan

Inagaki

Koga

Morishima

et al. 2012

Journal of Nuclear Science and Technology

View full text Add to dashboard Cite

The concentrations of 222 Rn existing in air have been studied by using a convenient and highly sensitive Pico-rad detector system at Masutomi spa in Yamanashi Prefecture, Japan. The measurements in air were carried out indoors and outdoors during the winter of 2000 and the summers of 1999 and 2005. The concentrations of 222 Rn in spring water in this region were measured by the liquid scintillation method. The concentrations of natural radionuclides contained in soils surrounding spa areas were also examined by means of the g-ray energy spectrometry technique using a Ge diode detector to investigate the correlation between the radionuclides contents and 222 Rn concentrations in air at each point of interest. The atmospheric 222 Rn concentrations in these areas were high, ranging from 5 Bq/m 3 to 2676 Bq/m 3 . The radon concentration at each hotel was high in the order of the bath room, the dressing room, the lobby, and the outdoor area near the hotel, with averages and standard deviations of the concentration Rn in the air in the bath room is more likely to be the spring water than the soil. The spring water plays carries the radon to the atmosphere. Our measurements indicated that the 222 Rn concentration in the air was affected by the 222 Rn concentration in spring water rather than that in soil.

show abstract

“…However, the population remains as a time dependent factor which influences the collective dose, and in turn the nation-wide per capita dose. Because Japanese geology is complex and differs largely depending on the 1ocation('0)" (12), the radiation level is also generally a function of location. And it can be generally said that most cities in Japan locate on alluvial plains or basins composed of volcanic ash or humus where the concentrations of radionuclides are low('").…”

Section: Introductionmentioning

confidence: 99%

Decrease ofper capitaNatural Radiation Dose in Japan in the Last Three Decades

Fujitaka¹,

Abe²,

Fujimoto³

1981

Journal of Nuclear Science and Technology

Self Cite

View full text Add to dashboard Cite

T h e long term variation of the mean dose due to natural radiation in Japan received by an individual person was investigated. T h e mean exposure rate in each prefecture obtained by in-situ measurements was adopted a s a basis of the radiation level. Population data were taken from both the resident registration and the census taking into account the essential difference of their meanings. It was revealed that the per capita dose due to outdoor natural radiaiton in Japan has been decreasing in the last approximate 30yr. It will be due to the population movement from countrysides towards urban areas. T h a t is because countrysides generally consist of stable mountainlands where granitic rocks distribute though urban areas generally consist of alluvial plains where volcanic ash or humus dominates. Although the contribution of low radiation level (below 9.0 ,uR/h) areas to the nation-wide collective dose still remains under 50%, its relative importance has certainly been increasing in the last three decades. It is expected that human population will be the dominating factor which eventually controls the mean dose due to natural radiation in Japan.

show abstract

Analysis of Contour Map of Natural Radiation in Japan

Cited by 5 publications

References 3 publications

Low-Cost Sensor Deployment on a Public Minibus in Fukushima Prefecture

Low-Cost Sensor Deployment on a Public Minibus in Fukushima Prefecture

Effect of spring water on the radon concentration in the air at Masutomi spa in Yamanashi Prefecture, Japan

Decrease ofper capitaNatural Radiation Dose in Japan in the Last Three Decades

Contact Info

Product

Resources

About