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Titel |
The non-destructive measurement of soil water content of upper part of the cave using soft component of air shower |
VerfasserIn |
A. Taketa, H. K. M. Tanaka, S. Okubo |
Konferenz |
EGU General Assembly 2012
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 14 (2012) |
Datensatznummer |
250061878
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Zusammenfassung |
We have developed a new radiographic method to measure the time variation of the water
content of the soil with soft component of air shower.
Air shower produced by a primary cosmic ray consists of hard component and soft
component. Hard component is mainly consists of muon, and soft components is consists of
electron, positron and photon. The penetration power of soft component is weaker than that
of hard component, so soft component is suitable for small scale structure thinner than 2
kg/cm2 equivalent to 20m thick water, like buildings and small hills. But it requires particle
identification which means distinguishing hard component and soft component.
Particle identification can be done with strong magnets and dense detectors, but it is
very hard to use that kind of detector for radiography because of their weight and
cost.
We established the cheap and effective method to distinguish soft component and hard
component statistically. We also performed measurements in Arimura observation
pit of Mt. Sakurajima, Japan. As a result of this observation, we found there is
an anti-correlation between soft component flux and rainfall. If the water content
of the soil became larger, the amount of absorption increases. So this result can
be interpreted as detecting the increase of the water content by soft component
flux.
This method can be applied for the quantitive compensation of the measurement data like
absolute gravitymeter data and tiltmeter data which is easy to receive turbulence by rain. It is
also expected that the quantitive compensation leads to the improvement in accuracy of
diastrophism measurement and the improvement in presumed accuracy of magma movement
inside a volcano.
We will report this newly developed radiography method using soft component for small
scale structure in detail and the result of measurement. Further improvement and possible
application are also discussed. |
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