Search

The RENO experiment has been taking data since August 2011 and successfully measured the smallest neutrino mixing angle, theta13, with neutron captured on Gadolinium (n-Gd) in target detector region. The experiment has also measured the mixing angle using an independent sample of neutron captures on Hydrogen (n-H). Because of a large accidental background in the n-H sample, an improved technique has been developed to make an effective removal of the background. The n-H analysis utilizes events in both target and gamma-catcher and thus obtains a more than twice larger sample than that of n-Gd. This independent measurement provides an important cross-check on the systematic uncertainties of the theta13 measurement from the n-Gd sample. In this presentation, we will also present a combined result based on the n-H rate-only and n-Gd rate-and-spectrum measurements.

For reactor neutrino experiments including the next--generation experiments will be adopting the liquid scintillator technique, criteria and time to select neutrino--induced inverse beta decay events from the background events need to be established. For higher performance efficiency, we investigated the results of applying a machine learning technique embedded in a standard ROOT package to select IBD signals. To obtain a higher statistics, the signals and background events in a gadolinium-loaded liquid scintillation detector were reproduced by Monte Carlo simulation. We report the efficiencies of neutrino--induced $n-H$ and $n-Gd$ events selection using the machine learning technique., Comment: 9 pages, 9 figures