Directional Counter for the Determination of the Complete Azimuthal Effect of Primary Cosmic Radiation

Abstract

The apparatus which the authors designed, constructed, and operated at the Institute of Physics of the National University of Mexico for the purpose of determining the azimuthal variation of primary cosmic radiation at fixed zenith angles consists essentially of four triple-coincidence Geiger-Müller telescopes mounted at zenith angles of 0°, 20°, 40°, and 60°, and are so arranged that, by rotation around a vertical axis, the directional intensity or counting rate can be measured at 16 equally spaced azimuths. The rotation and photographic recording are fully automatic. Several novel features of the apparatus are discussed here, most notable of which is the feature that, in contradistinction to the usual parallel connection of the three counters, as used in the conventional Rossi circuit and necessitating an amplifier tube for each Geiger-Müller counter, a material simplification of the circuits was obtained by connecting the three counters in series feeding a single stage of amplification.