Gamma Strength From Quasi-Continuum Lifetimes

Leo Kirsch, University of California, Berkeley

Photo of Leo Kirsch

A new experimental method is presented to normalize the Gamma Strength Function (GSF) using proton-gamma coincidences from <sup>56</sup>Fe(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 <sup>56</sup>Fe GSF normalization.

Abstract Author(s): Leo Kirsch, L.A. Bernstein, K.A. Van Bibber, W. Haxton, A.O. Macchiavelli, H.L. Crawford, M.D. Jones, C.M. Campbell, M. Cromaz, I.Y. Lee, P. Fallon, R.M. Clark, D.L. Bleuel, A. Hurst, D.G. Sarantities, M. Wiedeking, S. Zhu