Measurement of the cross section for the reactionI127(νe,e−)Xebound states127with neutrinos from the decay of stopped muons

The cross section for the reaction 127I(neutrino,electron)127Xe_(bound states) has been measured for electron neutrinos from the decay of stopped muons to be [2.84 +/- 0.91 (stat) +/- 0.25 (syst)] x 10^(-40) cm^2. A tank containing 1540 kg of 127I in the form of NaI solution was placed 8.53 m from the LAMPF beamstop where it received a typical flux of 5 x 10^7 neutrinos/(cm^2 s). The 127Xe atoms produced by neutrino capture were extracted from the target solution, placed in miniature proportional counters, and their number was determined by counting. This is the first measurement of a neutrino capture cross section for an I nucleus and is in good agreement with a recent calculation.