Atmospheric gamma-ray observation with the BETS detector for calibrating atmospheric neutrino flux calculations

K. Kasahara, E. Mochizuki, S. Torii, T. Tamura, N. Tateyama, K. Yoshida, T. Yamagami, Y. Saito, J. Nishimura, H. Murakami, T. Kobayashi, Y. Komori, M. Honda, T. Ohuchi, S. Midorikawa, T. Yuda