Author/Authors :
A.G. Smith ، نويسنده , , G.S. Simpson، نويسنده , , J. Billowes، نويسنده , , J.L. Durell، نويسنده , , P.J. Dagnall، نويسنده , , S.J. Freeman، نويسنده , , M. Leddy، نويسنده , , A.A. Roach، نويسنده , , Anthony JF Smith، نويسنده , , A. Jungclaus، نويسنده , , K.P. Lieb، نويسنده , , Malvin C. Teich، نويسنده , , B.J.P. Gall، نويسنده , , F. Hoellinger، نويسنده , , N. Schulz، نويسنده , , I. Ahmad، نويسنده , , J. Greene، نويسنده , , A. Algora، نويسنده ,
Abstract :
Measurements of g-factors of excited states in barium and cerium fission fragments have been performed using time-integral perturbed angular correlations between secondary-fragment γ rays. Larmor precession angles have been obtained for the first Iπ = 2+ states in 144,146Ba and 146,148Ce as well as for the 92− state at 117 keV in 143Ba, the 72− state at 114 KeV in 145Ba and the first 4+ state in 150Ce. The deduced g-factor for the 2+ state in 146Ba provides substantiating evidence for a downward trend in 2+ g-factors with increasing neutron number, in line with Interacting Boson Model predictions for the neutron-rich barium isotoes, assuming the quenching of the Z = 64 shell gap for N > 88. The static hyperfine fields for implanted barium and cerium isotopes are found to be opposite in sign. These results constitute the first use of secondary-fragment γ-ray emission in the determination of g-factors of excited states in fission fragments.
