TY - JOUR
T1 - Azimuthally controlled observation of heavy cosmic-ray primaries by means of the balloon-borne emulsion chamber
AU - Kamioka, E.
AU - Hareyama, M.
AU - Ichimura, M.
AU - Ishihara, Y.
AU - Kobayashi, T.
AU - Komatsu, H.
AU - Kuramata, S.
AU - Maruguchi, K.
AU - Matsutani, H.
AU - Mihashi, A.
AU - Mito, H.
AU - Nakamura, T.
AU - Nanjo, H.
AU - Ouchi, T.
AU - Ozawa, T.
AU - Shibata, T.
AU - Sugimoto, H.
AU - Watanabe, Z.
N1 - Funding Information:
We are grateful to the staff of the balloon division of the Institute of Space and Astronautical Science (ISAS), Sagamihara,J apan, for the successful flight of our chamber. We also thank the staff of the emulsion division of the Institute of Cosmic Ray Research (ICRR, University of Tokyo) for valuable discussions and their helpful processing work of sensitive materials. This work was financially supported in part by ICRR (E40, 1989 and E35, 1991), and by ISAS(B50-31, 1989, and B30-61, 1991).
PY - 1997/2
Y1 - 1997/2
N2 - We have exposed an emulsion chamber with an area of 1.22 m2 on board of the balloon at an atmospheric depth of 8.9 g/cm2 for 15.8 h, which has been azimuthally controlled within the accuracy of Δφ = 0.5°. With the use of the east-west asymmetry effect of arriving cosmic-ray primaries, we can obtain the energy spectra for individual elements in the kinetic energy range from a few GeV/nucleon up to ∼ 15 GeV/nucleon. We present also the energy spectra obtained by the opening-angle method for the higher energy region, 5-1000 GeV/nucleon, for the elements not lighter than silicon. We find that the energy spectra obtained by the former method continue smoothly to those obtained by the latter, indicating that the energy determination using the opening-angle method is performed correctly. We compare also the present results with those obtained by the previous work. We find that the iron flux is in nice agreement with that obtained by the previous observation, the differential spectral index being constant, ∼ 2.5, up to a few TeV/nucleon, while in the case of the silicon component, it is ∼ 2.7 for 10-1000 GeV/nucleon in this work, significantly harder than the previous one, ∼ 2.9. We also report the flux of the sub-iron component and its abundance ratio to the iron component. We find the abundance ratio of [Z = 21-25]/iron is slightly less than those obtained previously in the higher energy region, ≥ 100 GeV/n.
AB - We have exposed an emulsion chamber with an area of 1.22 m2 on board of the balloon at an atmospheric depth of 8.9 g/cm2 for 15.8 h, which has been azimuthally controlled within the accuracy of Δφ = 0.5°. With the use of the east-west asymmetry effect of arriving cosmic-ray primaries, we can obtain the energy spectra for individual elements in the kinetic energy range from a few GeV/nucleon up to ∼ 15 GeV/nucleon. We present also the energy spectra obtained by the opening-angle method for the higher energy region, 5-1000 GeV/nucleon, for the elements not lighter than silicon. We find that the energy spectra obtained by the former method continue smoothly to those obtained by the latter, indicating that the energy determination using the opening-angle method is performed correctly. We compare also the present results with those obtained by the previous work. We find that the iron flux is in nice agreement with that obtained by the previous observation, the differential spectral index being constant, ∼ 2.5, up to a few TeV/nucleon, while in the case of the silicon component, it is ∼ 2.7 for 10-1000 GeV/nucleon in this work, significantly harder than the previous one, ∼ 2.9. We also report the flux of the sub-iron component and its abundance ratio to the iron component. We find the abundance ratio of [Z = 21-25]/iron is slightly less than those obtained previously in the higher energy region, ≥ 100 GeV/n.
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U2 - 10.1016/S0927-6505(96)00051-5
DO - 10.1016/S0927-6505(96)00051-5
M3 - Article
AN - SCOPUS:0031067088
SN - 0927-6505
VL - 6
SP - 155
EP - 167
JO - Astroparticle Physics
JF - Astroparticle Physics
IS - 2
ER -