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环境天然本底辐射主要由陆地γ辐射和宇宙辐射两大部分组成。陆地γ辐射主要由土壤或岩石中铀系、钍系和钾-40所产生。在低大气层,宇宙射线产生的剂量主要由μ介子和电子贡献。环境辐射水平通常用空气吸收剂量率表示,最常用的单位是μrad/h(即10~(-8)Gy-h~(-1))。FT-620环境γ-x 照射量率仪(以下简称 FT-620)基本上是参考了西德 PTB-7201闪烁剂量仪研制的,使用了早期的单位μR/h。
Environmental natural background radiation mainly by the terrestrial gamma radiation and cosmic radiation composed of two parts. Terrestrial gamma radiation is mainly generated from uranium, thorium and potassium in soils or rocks. In the low atmosphere, the doses produced by cosmic rays are mainly contributed by muons and electrons. The level of ambient radiation is usually expressed as the dose rate of air absorbed. The most commonly used unit is μrad / h (ie, 10 -8 Gy-h -1). The FT-620 environment The gamma-x exposure meter (FT-620) is basically a reference to the West Germany PTB-7201 scintillation dosimeter developed using the earlier unit μR / h.