Messung der zirkularen Polarisation der inneren und äußeren Bremsstrahlung

Abstract

The polarisation of the internal bremsstrahlung γ's was detected by the Compton-forward-scattering with polarised electrons for three differentβ-decays: 1. for the allowed transition (P³²), 2. for the unique forbidden transition (Sr⁹⁰+Y⁹⁰), and 3. for the forbidden transition with forbidden spectrum (Bi²¹⁰=RaE). The detected polarisation values of P³² and (Sr⁹⁰+Y⁹⁰) agree with the theoretical values for the allowed transitions. The detected polarisation values for Bi²¹⁰ are smaller than the theoretical values of the allowedβ-transition by a factor of 0.62±0.08.

The polarisation of the external bremsstrahlung was measured as a function of the atomic number (Z) using thick absorbers. The polarisation of the external bremsstrahlung decreases slowly with the increase of the atomic number. The polarisation of bremsstrahlung, which was extrapolated to an absorber with atomic numberZ=0, is in well agreement with the theoretical values of the infinitively thin absorbers.