Double detector

摘要

A double detector, which consists of two gas ionization chambers (3, 5) arranged one behind the other in the radiation direction (1), is provided for separate and simultaneous measurement of alpha radiation and beta radiation which are jointly emitted by a radiation source. The chamber (3) facing the radiation source is operated for measuring the alpha activity in the ionization region. The chamber (5) facing away from the radiation source is operated for measuring the beta activity in the proportional region. Suitable dimensioning of the inlet window (11), of the gas volume of the alpha chamber (3), and of the separating window (9) ensures that essentially all the alpha radiation entering the double detector is absorbed in the alpha chamber (3). The beta activity, which is measured by means of the beta chamber (5), is thus not corrupted by alpha radiation. <IMAGE>