1981年 · 第01卷第05期

The experiment is based on the principle of the microdosimetry. A spherical tissue equivalent proportional counter (LET-SW1/2) is filled to a pressure of 57.1 mmHg with the tissue equivalent gas (62.7% CH₄, 34% CO₂, 3.2% N₂ and 0.1% O₂ by vo¬lume) to simulate the tissue diameter of one micron. We have measured the frequency distribution of event size p (Y) for californium-252 neutron source and computed the dose distribution of event size D (Y) .

The text described mainly the experiment method of the microdosimetry and the procedure of the data processing.

This paper describes animal experiments carried out in an uranium mine gallery for the purpose of investigating the relationship between animals' exposure to radon and its daughters and the incidence of chronic health hazards. 100 white rats and 400 C-57 black rats were placed in the atmosphere with high level radon and its daughters in an uranium mine to undergo experiments of radon inhalation. Their accumulated exposure doses were 2500 and 1170 WLM respectively. After a continued observation over a period of one year and nine months, no remarkable increment of lung cancer incidence due to radon and its daughters was noted in the animals.