大面積線源用多線式2πガスフロー計数管
1964 年 33 巻 5 号 p. 348-354
詳細
1964 年 33 巻 5 号 p. 348-354
A multi-anode 2rr gas flow counter for the absolute determination of radioactivity of large area sources, 14cm×18cm for one, is described.
The cathode comprises two parallel brass plates which are parts of the counter casing. Five equally 30mm-spaced anode wires of stainless steel and 0.05 mmø are stretched in a plane parallel to, and at 15.5mm from each of, the cathode plates. A large area source of the thickness of up to several mm is put on the lower cathode plate. Usually, methane gas is used as the proportional region counting gas.
In the proportional region, the prrallel plate type cathode has advantages over other types. Narrowing of the anode wire spacing does not very much improve the counter characteristics. Even in the GM region, the mutual interference of anode wires has no significant effect on the measurement.
