Energy resolution of experiments with quasi monoenergetic annihilation photons and structure of a giant dipole resonance

摘要

Reasons behind the known systematic discrepancies between the results of photonuclear experiments performed with different photon beams are investigated in detail. Information about the cross sections obtained for the reactions Cu-63(gamma, n)Cu-62 and Au-197(gamma, xn) at all stages of experiments with quasimonoenergetic photons from relativistic positrons annihilating in flight is studied, and a comparison with the data of experiments with beams of bremsstrahlung gamma radiation is performed. Data obtained in experiments of both types for the reaction O-16(gamma,xn) are used in the present analysis. It is shown that the difference procedure typically used experiments with quasimonoenergetic annihilation photons hinders the estimation of the actual energy resolution substantially, thus leading to a considerable distortion of information about the structure of cross sections for photonuclear reactions. (C) 2004 MAIK "Nauka/Interperiodica".