权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Observations of radon at the Kamioka Mine and earthquake prediction

神冈矿山的氡气观测与地震预测

基本信息

批准号：
04452026
负责人：
TASAKA Shigeki
金额：
$ 4.22万
依托单位：
Gifu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04452026/
关键词：
Radon observation Underwater radon detector Gass separatin film PIN photodiode KAMIOKANDE experiment Earthquake prediction Radon emanation rate Deep underground experiment 地下実験ラドンニュートリノ

项目摘要

We newly developed an underwater radon detector for ^<222>Rn concentration determinations in water. A PIN photodiode, an alpha particle detector, installed inside a container attracts radon families when charged electrostatically. Alpha particles emitted from ^<218>Po(RaA), ^<214>Po(RaC'), ^<210>Po(RaF) and ^<212>Po(ThC') are completely isolated from each other. This system cam be applied to a half year period observation for wide variation of radon concentrations from 0.5(Bq/m^3) in pure water to 10,000(Bq/m^3) in underground water. The observed results of pure water radon concentration in the KAMIOKANDE Tank showed that this technique is valid for the monitor of the degasfication system.Radon emanation rate were measured from various detector materials in KAMIOKANDE.The expected radon concentration from the exhalation in detector materials was estimated to be about 0.03(Bq/m_3). This value is 1/20 of the observed radon concentration 0.5(Bq/m^3) in KAMIOKANDE.This system can be applied to three years period observation for wide variation of radon concentrations in the fault underground water. The observed results of underground water radon concentration at a depth of 1,000(m) in the Kamioka Mine showed that this technique is valid for earthquake prediction. Significant decrease in the radon concentration were observed about two and a half days before a magnitude 3.9 earthquake occurred on Atotsugawa fault, and about ten days before a magnitude 4.7 earthquake occurred on the center of Gifu Prefecture.

我们新研制了一种用于水中氡浓度测定的水下氡探测器<222>。安装在容器内的PIN光电二极管（α粒子探测器）在静电充电时吸引氡族。从^<218>Po（RaA）、^<214>Po（RaC '）、^<210>Po（RaF）和^<212>Po（ThC'）发射的α粒子彼此完全隔离。该系统可用于半年的氡浓度观测，观测范围从纯水中的0.5（Bq/m^3）到地下水中的10,000（Bq/m^3）。通过对KAMIOKANDE水池中纯水氡浓度的观测结果表明，该技术可有效地用于除气系统的监测，并对KAMIOKANDE水池中各种探测材料的氡析出率进行了测量，估算出探测材料中氡析出的期望浓度约为0.03（Bq/m_3）。该系统可用于断层水氡浓度变化范围大的三年周期观测。对神冈矿1,000米深处地下水氡浓度的观测结果表明，该技术对地震预报是有效的。在Atotsugawa断层发生3.9级地震前约两天半和岐阜县中心发生4.7级地震前约十天，观察到氡浓度显著下降。