A New Cosmic‐Ray Recorder and the Air‐Absorption and Decay of Particles

Abstract

A new photographic recorder registering cosmic‐ray threefold coincidences without any screen is described. The analysis of the first data obtained shows that the partial correlation of the daily means with the heights corresponding to a pressure‐level in the atmosphere is greater the higher the selected pressure‐level from the ground, up to about 16 km. Supposing that the mesons are generated at the layer of 75 mm Hg., the true absorption‐coefficient and the mean rate of decay can be calculated. For the absorption‐coefficient it is found that μ = 1.68 × 10 −3 cm 2 /g, and for the rate of decay μ′ = 0.054 per km. From the value of μ′ it results that for the mean range of the meson before disintegrating spontaneously L = 18.6 km, and for the mean life of a meson of 3 × 10 9 ‐ev energy, when at rest, τ 0 = 1.6 × 10 −6 sec. Finally, for the temperature‐coefficient the value −0.35 per cent per 0 C was obtained.