Gamma Strength From Quasi-Continuum Lifetimes

A new experimental method is presented to normalize the Gamma Strength Function (GSF) using proton-gamma coincidences from ⁵⁶Fe(p,p'g) with an excitation dependent variation of the Doppler Shift Attenuation Method where lifetimes of quasi-continuum states delay low-lying gamma-ray transitions by an amount inversely proportional to the GSF magnitude. The E-dE scintillator array Phoswich Wall measures proton energies which designate initial nuclear excitation energy. The gamma-ray tracking spectrometer GRETINA measures signature gamma-ray transitions which designate the fed low-lying level. Doppler shift indicates gamma-ray cascade time if comparable to the nuclear stopping time. Results provide the first ⁵⁶Fe GSF normalization.