''Quasidirect'' observations of cosmic-ray primaries in the energy region 10/sup 12/--10/sup 14/ eV

Journal Article · Tue Aug 01 00:00:00 EDT 1989 · Phys. Rev. D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.40.729· OSTI ID:6031399

Kawamura, Y; Matsutani, H; Nanjyo, H; Teraoka, K; Toda, K; Ichimura, M; Kirii, K; Kobayashi, T; Niihori, Y; Shibata, T; others, and

We have exposed an emulsion chamber at a level of 32.8 g/cm/sup 2/ for /similar to/30 h, and detected /similar to/800 showers on x-ray films (Fuji No. 200 type). Among these, /similar to/200 primaries(/Sigma/ /ital E//sub /gamma///ge/2TeV, /theta//lt/75/degree/) were identified by tracing back through successive plates of nuclear emulsion. On the basis of these primaries, we obtain /ital I//sub /ital p//(/ge/E/sub 0/)=1.02/times/10/sup /minus/5/ (/ital E//sub 0//(1 TeV))/sup /minus/1.82/plus minus/0.13/ (cm/sup 2/ sec sr)/sup /minus/1/ in the region 5/approx lt//ital E//sub 0//approx lt/100 TeV for proton primaries, and /ital I//sub /alpha//(/ge/E/sub 0/) =6.50/times/10/sup /minus/7/(/ital E//sub 0//(1 TeV/nucleon))/sup /minus/1.75/plus minus/0.15/ (cm/sup 2/ sec sr)/sup /minus/1/ in the region 3/approx lt//ital E//sub 0//approx lt/10 TeV/nucleon for /alpha/ primaries. We observed also many atmospheric secondary /gamma/ rays, which cover the energy region 2--80 TeV. The /gamma/-ray spectrum is a rather smooth continuation of that obtained by Nishimura /ital et al./ in the region 0.2--2 TeV. The higher-energy part of our flux, however, cannot be reproduced by the atmospheric nuclear interaction of the primary protons and /alpha/ particles alone, indicating that, for energies /approx gt/10/sup 14/ eV/nucleus, the contribution of heavier primaries becomes significant, and that the latter flux may very well become comparable with the proton flux somewhere between 10/sup 14/ and 10/sup 15/ eV/nucleus. This indication is consistent with the iron flux obtained directly by the present experiment, though poor statistics preclude a conclusive result.

• Research Organization: Department of Physics, Hirosaki University, Hirosaki, Japan (JP); Department of Physics, Aoyama Gakuin University, Tokyo, Japan
• OSTI ID: 6031399
• Journal Information: Phys. Rev. D; (United States), Vol. 40:3
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC ALPHA PARTICLES
ENERGY SPECTRA
COSMIC PROTONS
COSMIC RAY DETECTION
COSMIC RAY FLUX
EXTENSIVE AIR SHOWERS
GAMMA SPECTRA
NUCLEAR EMULSIONS
PRIMARY COSMIC RADIATION
TEV RANGE 01-10
TEV RANGE 10-100
ALPHA PARTICLES
BARYONS
CHARGED PARTICLES
COSMIC RADIATION
COSMIC SHOWERS
DETECTION
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
HADRONS
IONIZING RADIATIONS
NUCLEONS
PROTONS
RADIATION DETECTION
RADIATION FLUX
RADIATIONS
SECONDARY COSMIC RADIATION
SHOWERS
SPECTRA
TEV RANGE
640101* - Astrophysics & Cosmology- Cosmic Radiation