R&D Status of Nuclear Emulsion for Directional Dark Matter Search T. Naka, M. Kimura, M. Nakamura, O. Sato, T. Nakano, T. Asada, Y. Tawara and Y. Suzuki EAS Publications Series, 53 (2012) 51-58 Published online: 15 February 2012 DOI: 10.1051/eas/1253007