High-Altitude Measurements on Cosmic Rays: Penetrating Cosmic Ray Showers

Abstract

THE penetrating shower set P, described in a previous communication¹, has now been transported to the Scientific Station, Jungfraujoch, altitude 3457 metres (atmospheric pressure = 50 cm.), and the transition curves of penetrating showers, produced in paraffin, aluminium and lead placed over the set P, studied there. In addition to the apparatus illustrated in our earlier note, four unscreened trays of counters, E₁ . . . E₄ of areas 230, 460, 920 and 1, 840 cm.² respectively, were placed near the penetrating shower set, P, for recording the presence of air showers. Also the side and end screens of the set, P, were increased from 10 cm. to 15 cm. of lead. The seven-fold coincidences of P were recorded and, in addition, coincidences in P accompanied by a discharge of each of the four air-shower trays were recorded separately.