Level density and {gamma}-decay properties of closed shell Pb nuclei

Journal Article · Sun Feb 15 04:00:00 EST 2009 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.79.024316· OSTI ID:21199552

Syed, N U. H.; Guttormsen, M; Ingebretsen, F; Larsen, A C; Rekstad, J; Siem, S ^[1]; Loennroth, T ^[2]; Schiller, A; Voinov, A ^[3]

---

1. Department of Physics, University of Oslo, P. O. Box 1048 Blindern, N-0316 Oslo (Norway)
2. Department of Physics, Aabo Akademi, FIN-20500 Aabo (Finland)
3. Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701 (United States)

The level densities and {gamma}-ray strength functions of {sup 205-208}Pb have been measured with the Oslo method, using the ({sup 3}He,{sup 3}He{sup '}{gamma}) and ({sup 3}He,{alpha}{gamma}) reactions on the target nuclei {sup 206}Pb and {sup 208}Pb. The extracted level densities are consistent with known discrete levels at low excitation energies. The entropies and temperatures in the microcanonical ensemble have been deduced from the experimental level density. An average entropy difference of {delta}S{approx}0.9k{sub B} has been observed between {sup 205}Pb and {sup 206}Pb. The {gamma}-ray strength functions in {sup 205-208}Pb have been extracted and compared with two models; however, none of them describe the data adequately. Intermediate structures have been observed in the {gamma}-ray strength functions for {gamma}-ray energies below neutron threshold in all the analyzed Pb nuclei. These structures become less pronounced while moving from the doubly magic nucleus {sup 208}Pb to {sup 205}Pb.

• OSTI ID: 21199552
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 2 Vol. 79; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA DECAY
ENERGY-LEVEL DENSITY
ENTROPY
EXCITATION
GAMMA DECAY
GAMMA RADIATION
HELIUM 3
INTERMEDIATE STRUCTURE
LEAD 205
LEAD 206 TARGET
LEAD 207
LEAD 208 TARGET
MAGIC NUCLEI
NEUTRONS
STRENGTH FUNCTIONS