Summary
Nonscreen-type X-ray films were commonly used to detect electromagnetic cascade showers developed in emulsion chambers. The detection threshold energy of the showers with the nonscreen-type X-ray film is about 500 GeV to 1 TeV, depending on exposure and development conditions. In order to improve the detection threshold, we examined various screen-type X-ray films. Thus, we found that combinations of a Gd2O2S: Tb phosphor screen and a green sensitive X-ray film show very high sensitivity, not only to cascade showers, but also to high-energy heavy ions. In order to extract the maximum performance of the screen-type X-ray film for the detection of cascade showers, we widely examined the effect of development conditions for the X-ray film and also analyzed the radiative transfer of photons in a Gd2O2S: Tb phosphor screen. Since we found that the optimum thickness of phosphor is about 500 μm, we prepared a special screen, type-GS, with a phosphor layer of 500 μm and applied it to balloon observations of high-energy galactic electrons. The improvement in the sensitivity for showers is remarkable and a detection threshold of 150 GeV, the predicted value from our analysis, has been attained with this special screen, type-GS. We have also found that a charge resolution of about 1.2 charge units is attainable for relativistic iron nuclei by using the average density of successive dark spots on ten sheets of screen-type X-ray film. The characteristics of the screen-type X-ray film, and its applications to observations of cosmic-ray electrons and heavy primaries and described in this paper.
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M. Akashi, Z. Watanabe, A. Misaki, I. Mito, Y. Ohyama, S. Tokunaga, T. Ogata, Y. Tsuneoka, S. Dake, K. Yokoi, S. Hasegawa, J. Nishimura, K. Niu, T. Taira, A. Snihio, Y. Fujimoto andN. Ogita:Prog. Theor. Phys. Suppl.,32, 1 (1964).
J. Nishimura, M. Fujii, T. Taira, H. Aizu, H. Hiraiwa, T. Kobayashi, K. Niu, I. Ohta, R. L. Golden, T. A. Koss, J. J. Lord andR. J. Wilkes:Astrophys. J.,238, 394 (1980).
T. Taira, T. Shirai, N. Tateyama, S. Torii, J. Nishimura, M. Fujii, A. Yoshida, H. Aizu, Y. Nomura, M. Kazuno, T. Kobayashi andA. Nishio:Proceedings of the XIX International Cosmic Ray Conference,6, 239 (1985).
Fuji Photo Film Co, Ltd:Manual for screen type X-ray film.
R. A. Buchanan:IEEE Trans. Nucl. Sci., NS,-19, 81 (1972).
J. A. de Poorter andA. Bril:J. Electrochem. Soc. Solid-State Sci. Technol.,122, 1086 (1975).
I. Ohta, K. Mizutani, K. Kasahara, T. Kobayashi, E. Mikumo, I. Mito, A. Ohsawa, K. Sato, S. Torii, M. Tsujikawa, S. Uchida, T. Yuda andY. Takahashi:Nucl. Instrum. Methods,161, 35 (1979).
G. I. P. Levenson:J. Photogr. Sci.,10, 280 (1962).
S. Chandrasekhar:Radiative Transfer (Clarendon, Oxford, 1950).
M. Ichimura, E. Kamioka, M. Kitazawa, K. Kirii, T. Kobayashi, T. Shibata, M. Kogawa, S. Kuramata, H. Matsutani, T. Murabayashi, H. Nanjo, H. Nanjo, Z. Watanabe, H. Sugimoto andK. Nakazawa:Nucl. Instrum. Methods A,300 374 (1991).
W. R. Webber, G. A. Simpson andH. V. Cane:Astrophys. J.,236, 448 (1980).
K. K. Tang:Astrophys. J.,278, 881 (1984).
R. L. Golden, B. G. Mauger, G. D. Badhwer, R. R. Daniel, J. L. Lacy, S. A. Stephens andJ. E. Zipse:Astrophys. J.,287, 622 (1984).
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Kobayashi, T., Fujii, M., Nishimura, J. et al. Improvements in the sensitivity of screen-type X-ray films for cascade showers and the charge resolution for heavy ions. Nuov Cim A 104, 1753–1770 (1991). https://doi.org/10.1007/BF02812490
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DOI: https://doi.org/10.1007/BF02812490