2005 Fiscal Year Final Research Report Summary
INVESTIGATION / STUDY ABOUT ENVIRONMENTAL RADIATIONS IN Mt.EVEREST AND NEIGHBORING AREAS
| Project/Area Number |
16510046
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Risk sciences of radiation/Chemicals
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| Research Institution | Nihon University |
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Principal Investigator |
NOGUCHI Kunikazu Nihon University, School of Dentistry, Lecturer, 歯学部, 講師 (00112954)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Mt.Everest / Kala Patthar / Gokyo Peak / Ionizing Component / Neutron Component / Cosmic Ray / Earth Gamma Rays / 1cm Dose Equivalent |
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| Research Abstract |
1.Distribution of Cosmic Ray Ionizing Component with Altitude
I got actual survey data of a 1cm dose equivalent rate of ionizing component of cosmic rays in Mt.Everest and neighboring areas (areas at a low geomagnetic latitude). If the 1cm dose equivalent rate of cosmic-ray ionizing components is shown as H_i (Z) (the unit is nSv/h) at the altitude of Z (the unit is km), it is expressed in approximation as follows :
H_i(Z)=20.3 exp(0.489Z)
2.Distribution of Cosmic Ray Neutron Component with Altitude
I got actual survey data of a 1cm dose equivalent rate of neutron component of cosmic rays in Mt.Everest and neighboring areas (areas at a low geomagnetic latitude). If the 1cm dose equivalent rate of cosmic-ray neutron components is shown as H_n(Z) (the unit is nSv/h) at the altitude of Z (the unit is kim), it is expressed in approximation as follows :
H_n(Z)=4.00 exp(0.616Z)
In addition, in a stone building of highlands race sherpa, it is expressed in approximation as follows :
H_n(Z)=3.11 exp(0.628Z)
3.Change of Earth Gamma Rays
I got actual survey data of a change of a 1cm dose equivalent rate of earth gamma rays in Mt.Everest and neighboring areas (areas between Lukla and Kala Patthar, areas between Lukla and Gokyo Peak). In addition, from energy analysis of gamma rays, I got 1cm dose equivalent rates to U series, Th series and potassium-40. It is enormous actual survey data and it is difficult to introduce it briefly. It is the first valuable actual survey data in the world, and it is necessary to analyze actual survey data in cooperation with mineralogical experts.
4.Future Prospects
Accumulation of actual survey data of earth gamma rays in the Himalayas except Mt.Everest area is expected, and accumulation of actual survey data of cosmic rays in low and high geomagnetic latitude areas is expected.
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