An investigation at sea level of cosmic-ray showers with sizes from 5× to over particles is described. The core locations, arrival directions, and particle density distributions of several thousand showers whose cores landed within an area of were determined by the techniques of fast-timing and density sampling. The most important results are as follows: (1) The existence of primary particles with energies greater than ev is established by the observation of one shower with more than particles. (2) The function , where and m, describes the lateral distribution of particles at distances in the range and for showers with sizes in the range . (3) At distances greater than 50 m from the core the density fluctuations in individual showers have a Poisson distribution. (4) The size and zenith angle distribution can be represented by the formula , where , g , , , g , , and . (5) No evidence is found of anisotropy in the arrival directions or of a break in the energy spectrum of the primaries up to the largest energies observed. (6) Assuming a specific model for shower development and taking into account fluctuations in the depth of the first interaction, the integral energy spectrum of the primaries is , where , , and .
- Received 13 December 1960
- Published in the issue dated April 1961
© 1961 The American Physical Society