Level densities and gamma-ray strength functions in Sn isotopes

Journal Article · Tue Jun 15 04:00:00 EDT 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.81.064311· OSTI ID:21388586

Toft, H K; Larsen, A C; Buerger, A; Guttormsen, M; Nyhus, H T; Siem, S; Syed, N U. H. ^[1]; Agvaanluvsan, U ^[2]; Mitchell, G E ^[3]; Schiller, A; Voinov, A ^[4]

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1. Department of Physics, University of Oslo, N-0316 Oslo (Norway)
2. Stanford University, Palo Alto, California 94305 (United States)
3. Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States)
4. Department of Physics, Ohio University, Athens, Ohio 45701 (United States)

The nuclear level densities of {sup 118,119}Sn and the gamma-ray strength functions of {sup 116,118,119}Sn below the neutron separation energy are extracted with the Oslo method using the ({sup 3}He,alphagamma) and ({sup 3}He,{sup 3}He{sup '}gamma) reactions. The level-density function of {sup 119}Sn displays steplike structures. The microcanonical entropies are deduced from the level densities, and the single neutron entropy of {sup 119}Sn is determined to be 1.7 +- 0.2 k{sub B}. Results from a combinatorial model support the interpretation that some of the low-energy steps in the level density function are caused by neutron pair breaking. An enhancement in all the gamma-ray strength functions of {sup 116-119}Sn, compared to standard models for radiative strength, is observed for the gamma-ray energy region of approx =4-11 MeV. These small resonances all have a centroid energy of 8.0(1) MeV and an integrated strength corresponding to 1.7(9)% of the classical Thomas-Reiche-Kuhn sum rule. The Sn resonances may be due to electric dipole neutron skin oscillations or to an enhancement of the giant magnetic dipole resonance.

• OSTI ID: 21388586
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 6 Vol. 81; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA DECAY
BARYONS
BINDING ENERGY
CHARGED-PARTICLE REACTIONS
DAYS LIVING RADIOISOTOPES
DECAY
DIPOLES
ELECTRIC DIPOLES
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY
ENERGY RANGE
ENERGY-LEVEL DENSITY
ENTROPY
EQUATIONS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FERMIONS
FIELD THEORIES
FUNCTIONS
GAMMA DECAY
GAMMA RADIATION
GRAND UNIFIED THEORY
HADRONS
HELIUM 3
HELIUM 3 REACTIONS
HELIUM ISOTOPES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LIGHT NUCLEI
MAGNETIC DIPOLES
MATHEMATICAL MODELS
MEV RANGE
MEV RANGE 01-10
MULTIPOLES
NEUTRON SEPARATION ENERGY
NEUTRONS
NUCLEAR DECAY
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
OSCILLATIONS
PARTICLE MODELS
PHYSICAL PROPERTIES
QUANTUM FIELD THEORY
RADIATIONS
RADIOISOTOPES
RESONANCE
STABLE ISOTOPES
STANDARD MODEL
STRENGTH FUNCTIONS
SUM RULES
THERMODYNAMIC PROPERTIES
TIN 116
TIN 118
TIN 119
TIN ISOTOPES
UNIFIED GAUGE MODELS