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The photograph shows the air shower event called "Andromeda" recorded in the X-ray film under 4 cascade units of lead of Camara 14. The event is visually composed of the following three parts.A. Black nucleus at the center. A characteristic dimension of its lateral size is ~1 em. Estimation on the total energy is obtained as 16,000 TeV by photometry measurement on the opacity of the X-ray films and the integration over the lateral spread and the depth variation through the chamber.B. Very high energy r-rays in the black nucleus. With help of microscopic observation on the nucleus part in their nuclear emulsion plates, one recognizes the existence of a number of very high energy cascade showers in a stream of numerous shower tracks of the black nucleus. It shows the existence of 30 r-rays (or electrons) with energy ranging 5~100 TeV in the nuclear region. Most of them are interpreted as originated from an atmospheric nuclear interaction of L;E7~400 TeV occurred~600 m above the chamber.C. Associated particles of the electromagnetic and the nuclear-active component in the outer region. In the outer region of ;cz em, we observe about 240 particles of the electromagnetic component with energy E 7;c1 TeV, sum of their energy being :EE7~550TeV. Besides, we observe 16 events of Pb-jet with EP,;c2TeV, their energy sum being :EEP,~50TeV. The total number of particles of the N-component will be about three-times of the above value because of the finite thickness of the chamber. Lateral distribution of the both components can be represented as exp( -r/ro)rdr with ro=5±0.5 em. Integral energy spectrum of the electromagnetic component is expressed as E-P with ,8=1.6±0.3. at North Dakota State University on May 30, 2015 http://ptps.oxfordjournals.org/ Downloaded from 4 C. M. G. Lattes et al. and M. Akashi et al. AbstractThis is a publication of results obtained by the collaboration experiment of the Brazil and Japan Emulsion Group over a period of nearly ten years since 1962. It is divided into five parts.I. Introduction gives a short description of the emulsion chambers exposed at Mt. Chacaltaya Laboratory (5200 m), Bolivia, ranging from Camara No. 1 of 0.4 m 2 up to Camara No. 15 of 44.2 m 2 , with a brief historical review of the collaboration experiment. Main part of the present results are obtained with Camara No. 12 (6m 2 ) and No. 13 (9.8 m 2 ), both of which have the producer layer for nuclear interactions in the chamber itself. II. Morphological Studies on Cosmic-ray Componentsgive the results on frequency, energy spectrum and zenith angle distribution of the electromagnetic and the nuclear-active components at Chacaltaya. The vertical flux for the electromagnetic component is (2.66 ·10-9 / cm 2 sec sterad)· (E/10 12 eV)-P with ,8=2.07±0.10, covering energy region of 2·10 11 eV~5·10" eV. Ratio of a flux value of the electromagnetic component to that of the nuclear-active component of the same visible energy is ~0.56, constant over the concerned energy region. III. Fire-l-all Studies on C-jets give detailed analysis on ...

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Characteristics of cosmic-ray hadronic interactions in the l00_1017 eV range are studied by observing a total of 429 cosmic-ray families of visible energy greater than 100 TeV found in emulsion chamber experiments at high mountain altitudes, Chacaltaya (5200 m above sea level) and the Pamirs (4300 m above sea level). Extensive comparisons were made with simulated families based on models so far proposed, concentrating on the relation between the observed family flux and the behaviour of high-energy showers in the families, hadronic and electromagnetic components. It is concluded that there must be global change in characteristics of hadronic interactions at around l0b~eV deviating from those known in the accelerator energy range, specially in the forwardmost angular region of the collision. A detailed study of a new shower phenomenon of small-pT particle emissions, PT being of the order of 10 MeV/c, is carried out and its relation to the origin of huge "halo" phenomena associated with extremely high energy families is discussed as one of the possibilities. General characteristics of such super-families are surveyed.