Proton capture to continuum states ofBi209

Abstract

High resolution spectra from fast proton radiative capture in 208 Pb are presented for three energies of the incident protons: 14.8, 15.7, and 16.9 MeV. The collected spectra were analyzed with emphasis on the region of capture to unbound states in order to search for possible structure and to study the competition between two basically different phenomena: the statistical process versus the fluctuation effects in radiative capture to unbound final states. In the energy region of incoming protons considered in our experiment, the statistical processes modeled with a Hauser-Feshbach calculation dominate. The spectra of primary γ rays, coincident with the low energy one from the decay of the f 7/2 single-particle state, show a prominent structure which is predominantly of g 9/2 character. The calculations of continuum spectra based on the extended direct-semidirect model and the Hauser-Feshbach statistical approach successfully reproduce the experimental data.

Hard gamma emission close to the GDR energy region

“…We have applied both approaches, the DSD model and the pre-equilibrium decay, to the reactions of proton radiative capture to discrete states in 208 Pb(p,γ), measured recently by Lipoglavšek et al [25,29]. As an example, we give here the γ energy spectrum obtained at three energies, namely 14.8, 15.7 and 16.9 MeV in coincidence with the 896 keV f 7 2¡ g.s.…”

Radiative nucleon capture - a dual approach

“…Recently, Lipoglavšek et al published detailed measurements of the 208 Pb(p,γ) reaction at incident energies between 8 and 19 MeV [19,20]. They presented the excitation functions of discrete states of 209 Bi populated in this reaction, and also the γ spectra for several incident energies.…”