Application of chi-square test to the identification of cosmic-ray hadron induced showers in emulsion chamber

A promising method is developed for the identification of the origin of showers, gamma-rays or hadrons, in emulsion chambers by studying longitudinal development of them. This method is based on the results of an extensive simulation calculations of cascade showers in emulsion chamber carried out by T. Shibata (Aoyama Gakuin Univ.), in which Landau-Pomeranchuk-Migdal effect and all the experimental conditions, such as spacing effect and so on, are exactly taken into account. The distributions of two standard quantities, Δt and chi*2, are obtained from a large number of simulated showers to measure the fluctuation of shower development and applied for the identification of the origins of showers by the comparison with measurements. (author)