E1-E2 interference in 159(ϒ,n) and 209(ϒ,n) reactions

Y. Birenbaum, Z. Berant, Sylvian Kahane, R. Moreh, A. Wolf

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Angular distributions of fast neutrons from the (ϒ,n) reactions on 159Tb and 209Bi were measured. Gamma sources in the 7 11.4 MeV range were obtained from (n,ϒ) reactions using thermal neu- trons. Pronounced asymmetries around 90° were observed for the angular distributions of photoneu- trons leading to the ground and a few excited states, in both the spherical 209Bi and the deformed 159Tb nuclei. These asymmetries indicate strong and similar E1-E2 interference effects in the two nuclei. The direct-semidirect model was modified to be used for target nuclei with one proton outside an even-even core. From a detailed comparison of the data with calculations using the modified direct-semidirect model, the contributions of different partial waves are estimated. Contributions of the compound nucleus process are included, and are shown to affect to some extent the calculated angular distributions energy dependence.

Original languageEnglish
Pages (from-to)2055-2064
Number of pages10
JournalPhysical Review C - Nuclear Physics
Issue number6
StatePublished - 1 Jan 1986

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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