title: Neutrino Induced Doppler Broadening.
abstract: When a nucleus undergoes beta decay via the electron capture reaction, it emits an electron neutrino. The neutrino emission gives a small recoil to the atom, which can be experimentally observed as a Doppler broadening on subsequently emitted gamma rays. Using the two-axis flat-crystal spectrometer GAMS4 and the electron capture reaction in (152)Eu, the motion of atoms having an excess kinetic energy of 3 eV in the solid state was studied. It is shown how the motion of the atom during the first hundreds of femtoseconds can be reconstructed. The relevance of this knowledge for a new neutrino helicity experiment is discussed.
authors.affiliation: Institut de Physique, Université de Fribourg, Pérolles, CH-1700 Fribourg, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Jolie
authors.affiliation: Institut de Physique, Université de Fribourg, Pérolles, CH-1700 Fribourg, Switzerland.
authors.forename: N
authors.initials: N
authors.lastname: Stritt
keywords: crystal spectrometer; gamma-ray spectroscopy; interatomic potentials; neutrino helicity; phonon creation