THE ANGULAR-MOMENTUM DEPENDENCE OF THE GIANT-DIPOLE RESONANCE IN DY-154

The statistical gamma-ray decay of the compound nucleus 154Dy formed at an excitation energy of 69 MeV is studied in three angular-momentum windows [J] = 31,42 and 50h. The GDR strength function extracted from the data indicates a constant centroid energy for the resonance E(GDR ) = 15.2 +/- 0.5 MeV, a small deformation of the nuclear shape for all spin regions and an increase in the resonance width with increasing a ngular momentum. The latter might indicate larger shape fluctuations a t higher angular momenta. A systematical study of the dependence of th e extracted strength function with different methods of analysis is pr esented, and their discrepancies discussed.