Okinoshima site study

The Okinoshima Islands are located on an off-axis of 0.76 degree (almost on-axis) with the same neutrino beam setting as T2K (2.5 degree off- axis to Kamioka). The distance of Okinoshima from the neutrino source, KEK/J-PARC, is 658 km. This configuration enables to conduct precision measurement of the 1st and 2nd neutrino oscillation maxima of the appearance electron neutrino energy spectrum. We have made studies of the Okinoshima Island site from the geological, geographic and infrastructure points of view to investigate the possibility of building a large underground cavern there to install a 100 kton class Giant Liquid Argon Time Projection Chamber (TPC) detector for a neutrino oscillation and proton decay experiment. We have found that the Okinoshima Island site is a good candidate site for such an observatory.