Relation between the primary neutron energy and neutron-induced proton energy. The left panel shows a correlation between the primary energy and the total deposited energy when background neutrons are injected to the detector. The black solid line means a linear function in case of completely reconstructed. The upper right panel represents the mean and the deviation of deposited energy for each injected. The lower right panel shows the ratio of deposited energy to injected (Nagai et al. 2014).