Sidereal Time Periodicity of Cosmic Rays and its Phase Shift

Abstract

WITH a coincidence apparatus—aperture in north-south direction 10°, east-west direction 40°—we have since July 1934 recorded continuously the intensity of the cosmic radiation (hourly records, sidereal time). The counters were arranged in the first series vertically ojpe above the other, and later with 36 cm. lead between the counters in vertical position of the plane of the counter axes, and the plane inclined 24°, 50° and 64° towards the south. The material of the total number, 720 days of observation was subjected, after reductions for barometer and terrestrial magnetic field effects, to harmonic analysis, whereby we determined the time and the amplitude of the first harmonic wave. Arranging the time of the occurrence of the maximum in accordance with the total thickness of the absorbing matter, we get as a first approximation a straight line connexion (Fig. 1). The equation of the line of regression has the following form: y = 29^h 40^m 0.90 E ± l^h 10^m (where E is the thickness of the absorbing material in metres of water), for the measurements in which the counters were filled with air (efficiencies about 27 per cent) ; and y = 33^h 4^m 0.94 E for counters filled with argon plus alcohol (efficiency about 95 per cent).