NEUTRINO-INDUCED DOPPLER-BROADENING STUDY ON ORIENTED EUO SINGLE-CRYSTALS

The motion of excited recoiling atoms produced by beta decay of Eu-152 causes a Doppler broadening of subsequently emitted gamma rays. The n eutrino-induced Doppler-broadened gamma-ray line shape is measured in oriented EuO single crystal targets using a high resolving power spect rometer. The motion and the slowing down of the emitting atoms depend on the forces exerted by the other atoms and on the direction of obser vation with respect to the crystal orientation. The comparison between measured and calculated gamma-ray line shapes obtained by molecular d ynamic simulation, permits to test different interatomic potentials an d slowing down theories. The dependence of the observed line shape on the crystal orientation is also investigated. [S0163-1829(98)01229-6].