Recordinds of Cosmic Radiation

The main purpose of the registrations reported here has been to study the diurnal variations of C. R. and especially to investigate how the amplitude and the phase of the variation depend on the direction of iniidence. Since statistical fluctuations will dominate over the significant ones unless a sufficiently large number of coincidences is counted, it has been necessary to use an apparatus with a high counting speed. C. R. has been recorded continuously in Stockholm (magn. lat. 58°) since 1. 10. 1947 by means of large counters in coincidence circuit. Recordings have been made in three different directions simultaneously, and the total number of particles counted amounts to 10⁹. The material has been analyzed with respect to diurnal variation. This analysis definitely proves that the variation is not the same in different directions. A term called C. R. activity has been introduced for the purpose of classifying the registrations according to the magnitude of the variation for each day. An analysis shows that large activity is very often observed during consecutive days.