Status of the Gadolinium project for Super-Kamiokande

EGADS (Evaluating Gadolinium’s Action on Detector Systems) is a test facility for a new neutrino detection method with a Gd-loaded water Cherenkov detector. In this method, anti-neutrino events with the charged-current interactions on protons are identified by the coincidental detections of the prompt positron signal from the inverse beta decay and the delayed gamma-ray signal from the neutron capture on Gd sulfate which is dissolved in the water. Introducing this method to a large water Cherenkov detector, Super-Kamiokande, we will achieve the first detection of the supernova relic neutrinos and improved ongoing physics studies with the capability of anti-neutrino identification and high precision measurement with reduced background. EGADS consists of the stainless tank holding 200 ton Gd solutions with two hundred forty 20inch PMTs and special water circulation system for filtration and gadolinium recovery. It is designed to evaluate the effect of dissolving Gd sulfate to water transparency and detectors. In 2011 and 2012, we tested the performance of water circulation system with the 15 ton buffer tank. At autumn 2012, we will install the PMTs to 200 ton tank and start detector commissioning with our DAQ. The current status of EGADS is presented.