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Author Higashi, S. ♦ Mitani, S. ♦ Oshio, T. ♦ Shibata, H. ♦ Watanabe, K. ♦ Watase, Y.
Sponsorship USDOE
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PHYSICS ♦ CLOUD CHAMBERS- COSMIC RADIATION- COSMIC SHOWERS- CROSS SECTIONS- EFFICIENCY- INTERACTIONS- IONIZATION- LEAD- LEVELS- - MEASURED VALUES- MUONS- PARTICLE TRACKS- PIONS- PLATES- PRODUCTION- SENSITIVITY- THICKNESS- UNDERGROUND- WILLIAMS-WEIZSAECKER METHOD ♦ CLOUD CHAMBERS- COSMIC RADIATION- COSMIC SHOWERS- CROSS SECTIONS- EFFICIENCY- INTERACTIONS- IONIZATION- LEAD- LEVELS- MEASURED VALUES- NUCLEONS- PARTICLE TRACKS- PIONS- PLATES- PRODUCTION- SENSITIVITY- THICKNESS- UNDERGROUND
Abstract A multiplate cloud chamber containing fifteen lead plates 1-cm thick was used to observe penetrating showers underground. Fifteen and twenty-three penetrating showers, having four secondary shower particles on the average, were obtained during 667.9 hours and 3603.1 hours at 50 mwe and 250 mee, respectively. Special attention was paid to distingish penetrating showers produced by mu mesons from these by the nucleonic component, the chamber of large width (100 cm) having been set as close to the upper wall in the tunnel as posslble. Almost all of the observed showers produced by isolated incident particles are considered as probably produced by mu mesons (named P-showers phenomenologlcally), and those by one of two or more incident particles as due to the nucleonic component (named S-showers), since the mfp of the nucleoric component for nuclear interaction is about 10/sup -4/ times shorter than that of mu mesons. After correcting for the triggering efficiency of the apparatas, the ratios of frequencies of S- showers to that of P-showers are 1.1 plus or minus 0.3 and 0.92 plus or minus 0.23 at both depths, which means that a half of the high energy nuclear interactions underground is produced by the nucleonic component. The depth dependence of frequencies of P-showers is compared with the prediction by Weizsacker and Williams' treatment of mu -meson interactions. It was observed that P-showers have a characteristic different from that of S-sbowers, i.e., the average number of heavily ionizing secondaries of P-showers is 0.3 per shower, while the value of S-showers is 2.8 per shower. (auth)
ISSN 00296341
Educational Use Research
Learning Resource Type Article
Publisher Date 1959-07-16
Publisher Department Osaka City Univ.
Journal Nuovo Cimento
Volume Number 13
Organization Osaka City Univ.


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