ISSN:
1434-601X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Profiles of the 264.6 keVγ-line of75As emitted after the electron capture decay of75Se have been measured using nuclear resonance fluorescence in combination withγγ-coincidences as a high resolution, variable-energyγ spectrometer. The sources consisted of gaseous75SeH2 with different amounts of Kr or Xe. From the line profiles information has been obtained about the velocity distribution of the radioactive75As ions after electron capture decay and about the slowing down of the75As ions in the moderator gas. The75As ions obtain kinetic energies of up toW∼5 eV by neutrino recoil and Coulomb fragmentation of the75SeH2 molecules, corresponding to velocities of the order of 105 cm s−1. The slowing down of the75As ions has been interpreted in terms of the model of colliding elastic spheres, taking into account the thermalization in an exact way. No satisfactory agreement has been obtained between measured and calculated line profiles. This result indicates that inelastic processes are of great importance in the interaction of75As ions or atoms with the noble gas moderator atoms.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01409387
