On the Density Spectrum and Structure of Extensive Air Showers

Experiments on the particle density spectrum and structure of extensive air showers were conducted in the Arctic regions by means of a G-M counter arrangement which allowed simultaneous measurements on showers of high and low densities. The mean densities investigated ranged from about 40 to 1000 particles/${\mathrm{m}}^2$. The integral density spectrum of shower particles at sea level was found to be $\mathrm{N}(>\mathrm{}\rho )=562\mathrm{}{\rho }^{-1.4\mathrm{}}$ ${\mathrm{hr}}^{-1\mathrm{}}$ $\rho$ in particles/${\mathrm{m}}^2$). With this spectrum it was possible to satisfy all the experimental data obtained with arrangements of various counter areas and multiplicities of coincidences. The decoherence curve of two counters, where extensive showers were first selected by a master coincidence, was found to be flat for small separations down to 7 cm, in disagreement with the results of other workers who did not select extensive showers. This result provides evidence against the existence of a large number of "cores" distributed throughout the extent of the shower.