Affiliation: | 1. Department of Physics, Tohoku University, Sendai, 980-8578, Japan;2. Laboratory of Nuclear Science, Tohoku University, Sendai, 982-0826, Japan;3. Ichinoseki National College of Technology, Ichinoseki 021-8511, Japan;4. Department of Electrical and Electronic Engineering, Akita University, Akita 010-8502, Japan |