Decoupling the effect of temperature on GDR widths in excited compound nucleus 144Sm

Abstract

We measured giant dipole resonance (GDR) γ-rays in the 28Si + 116Cd reaction at ∼105 and 120 MeV excitation energies. The resonance widths were extracted as a function of temperature at different angular momentum values to decouple the effect of these two variables on resonance widths. The high energy GDR γ-rays from the decay of compound nucleus (CN) 144Sm were measured using a large NaI(Tl) detector in coincidence with a sum-spin multiplicity filter. The experimental data were analyzed under the framework of statistical decay of CN. The GDR cross sections were also calculated with a thermal shape fluctuation model (TSFM), which incorporates the temperature and spin dependent shell corrections within the Nilsson–Strutinsky approach. The GDR widths were extracted in the temperature range 1.5–2.2 MeV. The measured widths indicate that the increase of GDR widths with temperature at different average spin values follows a similar trend and is borne out by theoretical calculations. Present calculation shows that TSFM satisfactorily reproduces the GDR cross section as well as widths in the temperature range 1–2.2 MeV over a wide range of angular momentum.