  In this study, we are doing R&D for directional dark matter search with
nuclear emulsion. First of all, higher resolution nuclear emulsion with fine
silver halide crystals was developed in the production facility of emulsion at
Nagoya university, and we confirmed that it can detect the expected nuclear
recoil tracks. The readout of submicron tracks was required the new technology.
We developed the expansion technique, and could readout the signal by shape
analysis with optical microscopy. The two dimensional angular resolution is 36
degrees at the original track length of range from 150nm to 200nm with optical
microscopy. Finally we demonstrated by using recoiled nuclei induced by 14.8MeV
neutron, and confirmed the technique.Moreover, we developed the X-ray
microscope system with SPring-8 as final check with higher resolution of
selected candidate tracks with optical microscopy. The angular resolution was
improved from 31 degrees with optical microscopy to 17degrees with X-ray
microscopy at the track length of range from 150nm to 250nm. We are developing
the practical system and planning for start of the test running with prototype
detector.
