T2K 2KM water Cherenkov detector

We propose building a detector at 2km position away from the neutrino production point of the T2K experiment. At this distance, almost the same neutrino flux is measured as that observed at the far detector. Using cancellation mechanism the water Cherenkov detector will enable to measure the νμ flux and νe backgrounds expected at far detector with smaller systematics. In this proceeding the detail studies using Monte Carlo simulation on the performance of the 2KM water Cherenkov detector and νe background measurement will be described.