Search

資料番号: AA0046651036

スクリーン型X線フイルムを用いた新しいタイプのエマルション・チェンバーを大気球に搭載して重一次宇宙線の観測を行った。露出面積, 露出時間および高度はそれぞれ1.22m^2,15.8h, 8.9g/cm^2である。この気球は飛行中も常に一定の方位を保つようにΔφ=0.5°以内の精度で方向規正されている。これにより, チェンバー内に降り注いでくる一次宇宙線の到来方向を測定できるので, 東西効果を用いて数GeV/nucleonから∿15GeV/nucleonのエネルギー領域でエネルギースペクトルを化学組成別に求めることができる。また, Si核より重い核についてはopening-angle法を用いて得られた5∿1000GeV/nucleonのエネルギー領域におけるエネルギースペクトルも紹介する。前者によって得られたエネルギースペクトルは後者によるものと極めて滑らかに接続しており, これはopening-angle法を用いたエネルギー決定法が信頼できるものであることを意味している。また, 今回の観測における解析結果を前回の観測のものと比較してみると, Fe核については非常に良い一致が見られ, 微分型スペクトルの"べき"は数TeV/nucleonまで∿2.5の一定値が得られた。一方Si核については, 今回の観測では10∿1000GeV/nucleonの範囲で"べき"は∿2.7であり, 前回の∿2.9と比べるとゆるやかな傾きになっている。さらに, sub-Fe核のfluxとFe核に対するそのabundance ratioも報告する。[Z=21-25]/Fe abundance ratioは, ∿100GeV/nucleon以上のエネルギー領域で前回の観測結果よりわずかに減少しているのがわかる。, We have exposed an emulsion chamber with the area of 1.22m^2 on board the balloon at an atmospheric depth of 8.9g/cm^2 for 15.8h, which has been azimuthally controlled within the accuracy of Δφ=0.5°. With 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∿15GeV/nucleon. We present also the energy spectra obtained by the opening-angle method for the higher energy region, 5∿1000GeV/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 silicon component, it is ∿2.7 for 10∿1000GeV/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, ≳100GeV/nucleon., 資料番号: SA0167085000

We have exposed a new type of emulsion chamber with full use of the screen-type X-ray film at a level of 11.7g/cm^2 for∿20h, and detected more than hundred thousand cosmic-ray heavy primaries, with charge of Z≳8. This article describes the charge resolution and the accuracy of energy determination for primary cosmic-ray nucleus, and report the absolute intensities of cosmic ray primaries heavier than silicon in the wide energy range, a few GeV/n to TeV/n and beyond. Our results of iron and silicon fluxes are both in agreement with those obtained recently by spacelab-2 experiment. It is particularly remarkable that the spectrum of silicon primaries becomes softer beyond the hundred GeV/n, with integral index of β∿1.95,which is hard to understand in the framework of current models for interstellar propagation as well as for acceleration mechanism. On the other hand, we found that the exponent of iron spectrum is almost constant with β∿1.5 up to a few TeV/n. We report also about the abundance ratio of sub-iron group to iron, which reflects strongly on the escape length of cosmic rays in the Galaxy. We discuss further the total primary flux, and find that the extrapolation of the direct observation data to the energy region of 10^ ∿10^eV/particle deviates slightly from those expected by air shower experiment., 資料番号: SA0167045000

We exposed emulsion chambers at the level of 32.8gr/cm^2 for∿30hrs, and∿800 showers were detected on X-ray films (Fuji #200-type), among which∿200 primaries (ΣE_γ≨2TeV, θ×(E_0/TeV)^ No./cm^2・sec・str in the region 5≲E_0≲*100TeV for proton primary, and I_a(≨E_0)=6.50・10^×(E_0/TeV・nucleon)^ No./cm^2・sec・str in the region 3≲E_0≲*10 TeV/nucleon for alpha primary. The former is clearly deviated from both data by Grigorov et al. and Zatsepin et al., and rather consistent with JACEE data. The latter is again in disagreement with Grigorov data, but nearly compatible with those obtained by JACEE and Zatsepin et al.. The γ-ray flux we observed covers the energy region 2∿80TeV, which is nearly consistent with the extrapolation from that obtained by Nishimura et al. in the region as low as 0.2∿2 TeV. We found, however, that it is much more abundant in our energy region than those coming from the proton-and alpha-primaries alone, indicating that heavy primaries, such as iron component, become effective in the primary energy 10^∿10^eV/nucleus., 資料番号: SA0166865000