Status of R&D of the ANKOK project: Low mass WIMP search using double phase argon detector

The ANKOK project is a new dark matter search experiment in Japan using the double phase liquid argon detector which is specialized for the low mass (∼ 10 GeV/c²) WIMP detection. We are currently proceeding R&D efforts to establish its physics sensitivity, such as understanding of the liquid argon scintillation and ionization processes for very low energy deposition (∼ 20 keV) and development of the new photo-sensor which has direct sensitivity for the 128 nm VUV light. In the next few years, we are targeting to construct a detector with fiducial mass of several tens of kg, and to collect the underground physics data to search for the low mass WIMP.