Etude des variations de l’intensité d’ionisation << α >> et << γ >>

Abstract

We plan to consider the variations of ionization produced in the air, near the ground, by the radiations “α” and “γ”. The equipment we used consists of two chambers of 120 liters: one, hermetically sealed, detects the component γ; the other, with circulation of ambiant air, detect α plus γ, which gives the possibility to estimate per difference, the component α. The chambers and the electronic measuring devices have been designed for permanent operation in open air. Another chamber, without wall, permits also to estimate directly the total intensity of ionization and to deduct from it an approximate value of component β. Series of recordings have been made around Saclay where natural radioactivity is at an average level and also where the level of radioactivity is either low or high (near the sea and in the mining branch of the E.A.C.). It is thus possible to make visible the variations of the component γ in function of the location where the measurements take place (from 3.7 to 6.3 I/cm 3 ·s) and the very great variations of component α at the same identical location (for instance, from 1,5 to 45 I/cm 3 ·s at Saclay). It is then possible to show that the variations of this component are accurately tied to the values of different meteorological parameters: rain, fog, pressure, wind and gradient of temperature. DOI: 10.1111/j.2153-3490.1966.tb00273.x