Environmental Geiger Counter/Spectrometry

  • One thing noteworthy is radon, and its gamma ray spectrum, especially from the daughter nuclide of Rn-222. In latest luxury hotels in Western countries and China (Often uses large amounts of granite and marble, maybe their procurement cost is low?), or even in Japan, old temples, entrance of a luxury high-rise building, old station square, stone steps, stone pavement, stone statue is heavy use of marble. In such facilities, relatively high value of radiation 0.1μSv / h ~ 0.25μSv / h derived from radon is observed. In cases of measurement on a stone statue, stone steps, and stone pavement appeared in some weekly magazines, I do not say cesium-derived radioactivity is not contained at all, but the main component of the radioactivity of such cases is often radon origin contained in granite and marble, though can't to be too sure without checking individual spectrum.
  • However, while natural radon and radium is detected in concrete buildings, stone statues, and stone buildings, a situation that in Kanto area, Japan, normal soil is contaminated with cesium of about 10,000 Bq / m ^ 2 order can not be overlooked.
  • When you observe 0.1μSv/h〜0.25μSv/h level radiation dose on stone pavement, stone steps, stone statue or by marble pillars, spectrometry is vital for appropriate measurement, or on the contrary, radon may leak and observed on normal soil. On concrete nor asphalt, even when relatively high value is observed, you must first look at the spectrum individually.
  • Prior to the environmental radioactivity measurement, it is useful to know examples of typical spectrum patterns interwoven by marble, granite, radium and radon in concrete, and artificial radioactivity such as cesium-134/137, can be observed at drainage ditches, and so on.
  • The pattern of the spectrum of artificial radioactivity may change along mixing ratio of Cs134/137, as half-life of Cs134 is short. Mixing ratio may vary according to the nuclear reactor of origin of the plume, there is also a change in the mixing ratio due to the difference in half-life.

  • 最終更新:2013-05-21 14:24:58

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