1972 年 92 巻 1 号 p. 37-41
^<220>Rn from 228Ra in thorium series was deposited electrically on a negative platinum plate. 208T1 was isolated from the above by a small-type electrophoresis and its half life was determined. The period of standing after isolation of 220Rn was discussed from the theory of the production and decay of 208T1. 207T1, which is isolated from the incipitate of 219Rn from 227Ac and whose γ-ray radiation (0.2%) is hardly identified was isolated and ascertained by the same procedure from the experimental result of 208T1. Electrolyte of 0.1M citric acid and cellulose acetate are used as a support at 1000 V/11 cm for the electrophoresis. The operating time from the parent nuclide to the isolation and determination should be in all within 4 min (electrophoresis, 2 min and other treatment, 2 min). The above result makes it clear that the small-type electrophoresis can be used for the isolation of short half-life nuclides such as 208T1 (3.1 min) and 207T1 (4.79 min).