Intensity anomaly in the (d,pγ) reaction

Abstract

The spectra of gamma rays detected in coincidence with protons from the (d,pγ) reaction in elements [Formula: see text] and [Formula: see text] have been measured in gross structure with a NaI detector. The region of excitation energies covered in the product nuclei was from 0.8 MeV to about the neutron separation energy, typically 7 MeV. The gamma-ray anomalous bump at about 5.5 MeV was found from regions near the separation energy with an intensity comparable to that previously observed in (n,γ) reactions. By gating techniques the decay of many contiguous intervals of excitation energy, populated in the reaction, was studied. From the results, a strength function for gamma rays between 0.8 and 7 MeV approximately was extracted for Au, where the bump is prominent, and for Ta where the bump is essentially absent. In the particular case of 206Pb(d,pγ)207Pb, the gamma-ray spectra are interpreted in terms of the decay of known single particle states. An interpretation of the intensity anomaly in terms of doorway states is discussed.