Status of Development of Antineutrino Detector for Short Baseline Experiment at the HANARO Research Reactor

As the burnup proceeds, the neutrino energy spectrum deviates from the initial one. Also the rate of antineutrino production is correlated to the amount of specific fissile elements in the reactor core. By monitoring the antineutrinos during the fission process in the reactor core, scientists can estimate the variation of fissile material. A recent report published by the Department of Safeguards of IAEA also said that a short baseline (SBL) neutrino detector has intrinsic characteristics for monitoring status, operation power and nuclear fuel composition ratio in real time outside the containment building of the nuclear reactor with no-interference mode. Also many reactor neutrino experiments have searched for neutrino flavor oscillation by measuring the electron antineutrinos produced in a nuclear reactor. Since the KamLAND experiments in 2002 gave a precise observation, the neutrino flavor oscillation model has been accepted as an actual phenomenon. One of the interesting issues on reactor neutrino is an anomaly in that an event number of measured neutrinos shows a deficit of 6% compared with the expectation, which means that there should be an undetected sterile neutrino in addition to the known three flavors. It should be created in the flavor oscillations, and does not participate in a weak interaction. The recent high precision and high statistics data from Double Chooz, Daya Bay and RENO experiments may imply this. The research project, which is funded by National Research Foundation of Korea (NRF), started on June, 2012, is developing a short baseline neutrino detector close to the HANARO research reactor, and the technology for reactor monitoring by measuring precisely the neutrino energy spectrum. It is also developing a liquid scintillator containing metals that have large neutron capture cross section, and pulse shape discrimination methods. We will then have a more flexible technology that can detect reactor neutrinos overground. A prototype detector was developed and now under performance tests including evaluation of background noise characteristics arised from environmental and cosmic rays, muon veto performance, pulse shaping discrimination of the neutrinos signal from those by other interfering radiations. Along with them, intense and extensive simulation works were carried out using Monte Carlo technique mainly focusing on the optimization of the signal to noise ratio. So many liquid scintillation matters have been tested as candidate for a prototype and a main detector, and a frontend electronics and data acquisition software were under development