Simultaneous observation of families and accompanied air showers at Mt. Chacaltaya

Abstract

Simultaneous observations of families and accompanied air showers with emulsion chambers and the air shower array of electronic equipment at Mt. Chacaltaya ͑5200 m, 540 g/cm 2 ͒ reveal that families bear the data of nuclear interactions generated deep in the atmosphere. 47 outstanding families with ⌺E ␥ у10 TeV are correlated with the accompanied air showers of the size 10 5 -10 8 . A scatter plot of the average family energy versus the size of the relative air shower requires further energy fractionizing process͑es͒ in the propagation of high energy cosmic rays in the atmosphere, such as a larger dissipative mechanism in nuclear interaction, heavier chemical composition of the primary cosmic rays, etc. We reach the conclusion that nuclear interaction changes its features in the energy region E 0 Ͼ10 16 eV, because the heavier composition, proposed so far, is not sufficient for the required dissipative process. A comparison with the data from the HADRON experiment at a similar altitude with a similar technique shows that no larger deviations are present between both experiments.

Emulsion chamber observations of Centauros, aligned events and the long-flying component

“…Chacaltaya (5200 m, Bolivia) [61,62], Yang-bajing (4300 m, China) [63][64][65] and Tien-Shan (3340 m, Kazakhstan) [66]. These experiments were designed to study nuclear interactions and the chemical composition of cosmic rays in the energy region around 10 15 − 10 17 eV.…”

“…Further details of the Chacaltaya hybrid experiment are described in Refs. [61,62]. In the Chacaltaya data, 1034 events in ∼ 40 m 2 year exposure of the hadron calorimeters satisfy the following criteria:…”

A systematic study of the hybrid experiment at Mt.Chacaltaya

“…However, the hybrid experiments, operating simultaneously an air-shower array, a hadron calorimeter and an emulsion chamber at Mt. Chacaltaya (5200m, Bolivia) [4,5], have been shown that the characteristics of the observed events in this energy region can not be fully explained simply by changing chemical composition of primary particles. In the hybrid experiments, we can obtain air-shower size, N e , from the air-shower array data, particle-density, n b , which are closely connected to the hadron component in the airshower, from hadron calorimeter (burst detector) and the energy and geometrical position of individual high energy electromagnetic particles of atmospheric families by the a e-mail: tamada@ele.kindai.ac.jp emulsion chamber.…”

The Anatomy of the Knee and Gamma-Families

“…Since then, in spite of both methods being well developed and widely used in cosmic ray ( CR ) studies they have remained basically independent of each other. However, there have been several attempts to combine them [4,5,6,7,8,9,10,11] and these combinations have brought interesting results. Inspired by these results a few new projects have been proposed to use large stacks of X-ray films within EAS arrays at mountain altitudes, where the intensity and the energy content of both EAS and gammahadron families is much higher than at sea level [12,13,14].…”