Feasibility study of 100 million tones water Cherenkov detectors which aim to open new era of elementary particle physics.

已对下一代核子衰变和中微子探测器进行可行性研究，其目的是探索基本粒子和物质主导的宇宙的统一。在国际竞争日趋激烈的今天，我们与国际社会建立了良好的关系，交流各国的现状和进步。这个1亿吨的探测器必须建造在地下，以屏蔽宇宙射线噪音。根据最近的各种研究，我们在日本完成了探测器的概念设计：地质调查，寻找适合巨大洞穴的坚硬岩石区域，洞穴形状的优化，光传感器的优化等。

Feasibility study has been performed for next generation nucleon decay and neutrino detectors which aim to explore unification of elementary particles and the matter-dominated Universe. We also made good relationship with the world community to exchange status and progress of each country while international competition is getting hard. This detector with the dimension of 100 million tones has to be constructed in underground to be shielded against cosmic ray noise. We have completed concept design of the detector in Japan based on recent various studies : geological survey to look for hard rock region suitable for the gigantic cavity, optimization of cavity shape, optimization of light sensors, and so on.