Neutrino absorption efficiency of an 40Ar detector from the β decay of 40Ti

We studied β-delayed proton and γ emission from 40Ti decay. We found t1/2=52.7±1.5 ms and observed 28 proton groups that we organized into a 40Ti 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 40Ar(ν,e) cross sections (for an electron energy threshold W=5 MeV) of (14.0±0.3)x10-43 cm2, (75.1±1.8)x10-43 cm2, and (3.2±0.1)x10-41 cm2 for 8B neutrinos, hep neutrinos, and supernova neutrinos characterized by a temperature of 4.5 MeV. copyright 1998 The American Physical Society