Conceptual Design Report of DaRveX: Decay at Rest νe + Lead Cross Section Measurement at J-PARC MLF

DaRveX stands for “Decay at Rest νe-Pb cross (X) section measurement”. So far, there has not been good target to detect low energy νe. Lead is expected to be an excellent νe target because the cross section is expected to be very large and the delayed coincidence technique can be used using final state neutron(s). However, the cross section have not been measured yet. If it is measured, it opens a new window to the future neutrino research field, such as low energy νe oscillation measurements, flavor specific detection of the supernova explosion νe and understanding of νe-nucleus interactions. This report explains a conceptual design of DaRveX experiment, which measures cross section of νe+Pb charged current interaction, νe(E~30MeV)+Pb → e−+xn+Bi; (x=1 or 2), using νe from μ+ decay at rest at J-PARC MLF. The energy and direction of the final state e− will be measured by using 1-ton scale lead-scintillator sandwich detector. With two years of data taking, the cross section is expected to be measured with 20% of precision.