Tracking performance of the NEWAGE-0.3a direction-sensitive dark matter detector

NEWAGE-0.3a is a prototype direction-sensitive dark matter search detector. We measured its response to electron tracks and nuclear tracks while focusing on the tracking performances in an underground laboratory. It showed a gamma-ray rejection power of 8.1 ± 1.9 × 10−6 at 100 keV α.e.(alpha-equivalent) and an energy resolutions of 45% at 6 MeV α.e. The absolute nuclear efficiency was 80% at 100 keV α.e. and the nuclear directional-dependent efficiency was also measured. The three-dimensional angular resolution for the nuclear track was 46 ± 3° in the energy range from 100 keV α.e. to 400 keV α.e.