Gamma-ray strength functions at low energy

Photon-scattering experiments were carried out with bremsstrahlung at gELBE and with quasi-monoenergetic gamma rays at HIGS. Strength in the quasicontinuum was included in the analysis. The observed strength was corrected for branching and feeding by means of statistical methods. Experimental information about E1 strength in the pygmy region and M1 strength in the spin-flip region is presented for nuclides around masses 80, 130 and 180.
Large-scale shell-model calculations of M1 and E2 strength were performed. The experimental low-energy upbend can be explained by enhanced M1 strength. Information about E2 strength at low energy is given. The described findings require modifications of phenomenological strength functions.