Author/Authors :
Motoki، نويسنده , , M and Sanuki، نويسنده , , T and Orito، نويسنده , , S and Abe، نويسنده , , K and Anraku، نويسنده , , K and Asaoka، نويسنده , , Y and Fujikawa، نويسنده , , M and Fuke، نويسنده , , H and Haino، نويسنده , , S and Imori، نويسنده , , M and Izumi، نويسنده , , K and Maeno، نويسنده , , T and Makida، نويسنده , , Y and Matsui، نويسنده , , N and Matsumoto، نويسنده , , H and Matsunaga، نويسنده , , H and Mitchell، نويسنده , , J and Mitsui، نويسنده , , T and Moiseev، نويسنده , , A and Nishimura، نويسنده , , J and Nozaki، نويسنده , , M and Ormes، نويسنده , , J and Saeki، نويسنده , , T and Sasaki، نويسنده , , M and Seo، نويسنده , , E.S and Shikaze، نويسنده , , Y and Sonoda، نويسنده , , T and Streitmatter، نويسنده , , R and Suzuki، نويسنده , , J and Tanaka، نويسنده , , K and Ueda، نويسنده , , I and Wang، نويسنده , , J.Z and Yajima، نويسنده , , N and Yamagami، نويسنده , , T and Yamamoto، نويسنده , , A and Yamamoto، نويسنده , , Y and Yamato، نويسنده , , K and Yoshida، نويسنده , , T and Yoshimura، نويسنده , , K، نويسنده ,
Abstract :
The vertical absolute fluxes of atmospheric muons and muon charge ratio have been measured precisely at different geomagnetic locations by using the BESS spectrometer. The observations had been performed at sea level (30 m above sea level) in Tsukuba, Japan, and at 360 m above sea level in Lynn Lake, Canada. The vertical cutoff rigidities in Tsukuba (36.2°N, 140.1°E) and in Lynn Lake (56.5°N, 101.0°W) are 11.4 and 0.4 GV, respectively. We have obtained vertical fluxes of positive and negative muons in a momentum range from 0.6 to 20 GeV/c with systematic errors <3% in both measurements. By comparing the data collected at two different geomagnetic latitudes, we have seen an effect of cutoff rigidity. The dependence on the atmospheric pressure and temperature, and the solar modulation effect have been also clearly observed. We also clearly observed the decrease of charge ratio of muons at low momentum side with at higher cutoff rigidity region.
