Neutrino absorption efficiency of an40Ardetector from the β decay of40Ti

Abstract

We studied $\ensuremath{\beta}$-delayed proton and $\ensuremath{\gamma}$ emission from ${}^{40}\mathrm{Ti}$ decay. We found ${t}_{1/2}=52.7\ifmmode\pm\else\textpm\fi{}1.5 \mathrm{ms}$ and observed 28 proton groups that we organized into a ${}^{40}\mathrm{Ti}$ decay scheme with 21 branches. The reduced transition strengths of these decay branches were then used to compute the neutrino detection efficiency of the ICARUS liquid argon time-projection chamber. We found ${}^{40}\mathrm{Ar}(\ensuremath{\nu},e)$ cross sections (for an electron energy threshold $W=5 \mathrm{MeV}$) of $(14.0\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}43} {\mathrm{cm}}^{2},$ $(75.1\ifmmode\pm\else\textpm\fi{}1.8)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}43} {\mathrm{cm}}^{2},$ and $(3.2\ifmmode\pm\else\textpm\fi{}0.1)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}41} {\mathrm{cm}}^{2}$ for ${}^{8}\mathrm{B}$ neutrinos, hep neutrinos, and supernova neutrinos characterized by a temperature of 4.5 MeV.