Fast neutron induced depopulation of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>180</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Ta</mml:mi></mml:mrow><mml:mrow><mml:mi>m</mml:mi></mml:mrow></mml:msup></mml:mrow></mml:math>isomer

Karamian, S. A.; Collins, C. B.; Carroll, J. J.; Adam, J.; Белов, А. Г.; Stegailov, V. I.

doi:10.1103/physrevc.59.755

Cited by 13 publications

(9 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The spread in the angular momentum distribution due to the statistical cascade is shown in this case, since it provides the only mechanism by which that distribution may be widened above the intermediate-state region. [22,26], and are similar to that expected here, with a narrow spin distribution concentrated near the high spin of the target nucleus. Other reactions in Table I provide isomer-to-ground-state ratios obtained for production of 179 Hf m2 and other isomers of similar structure in Lu and Hf nuclides [23,27].…”

Section: Resultssupporting

confidence: 86%

Cross section for inelastic neutron ``acceleration'' by178Hfm2

Karamian

Carroll

2011

Phys. Rev. C

Self Cite

View full text Add to dashboard Cite

The scattering of thermal neutrons from isomeric nuclei may include events in which the outgoing neutrons have increased kinetic energy. This process has been called inelastic neutron acceleration, or INNA, and occurs when the final nucleus, after emission of the neutron, is left in a state with lower energy than that of the isomer. The result, therefore, is an induced depletion of the isomer to the ground state. A cascade of several γ 's must accompany the neutron emission to release the high angular momentum of the initial isomeric state. INNA was previously observed in a few cases, and the measured cross sections were only in modest agreement with theoretical estimates. The most recent measurement of an INNA cross section was σ INNA = 258 ± 58 b for neutron scattering by 177 Lu m . In the present work, an INNA cross section of σ INNA = 168 ± 33 b was deduced from measurements of the total burnup of the high-spin, four-quasiparticle isomer 178 Hf m2 during irradiation by thermal neutrons. Statistical estimates for the probability of different reaction channels past neutron absorption were used in the analysis, and the deduced σ INNA was compared to the theoretically predicted cross section.

show abstract

Section: Resultssupporting

confidence: 86%

Cross section for inelastic neutron ``acceleration'' by178Hfm2

Karamian

Carroll

2011

Phys. Rev. C

Self Cite

View full text Add to dashboard Cite

show abstract

“…The excitation energy of the isomers is released by impinging neutrons, for example, via a compound nucleus reaction. It is sometimes referred to as a superelastic process [3,4], because the outgoing neutron is accelerated.…”

Section: Introductionmentioning

confidence: 99%

Calculation of nuclear reaction cross sections on excited nuclei with the coupled-channels method

et al. 2009

View full text Add to dashboard Cite

We calculate nuclear cross sections on excited nuclei in the fast neutron energy range. We partition the whole process into two contributions: the direct reaction part and the compound nuclear reactions. A coupled-channels method is used for calculating the direct transition of the nucleus from the initial excited state, which is a member of the ground-state rotational band, to the final ground and excited low-lying levels. This process is strongly affected by the channel coupling. The compound nuclear reactions on the excited state are calculated with the statistical Hauser-Feshbach model, with the transmission coefficients obtained from the coupled-channels calculation. The calculations are performed for a strongly deformed nucleus 169 Tm, and selected cross sections for the ground and first excited states are compared. The calculation is also made for actinides to investigate possible modification to the fission cross section when the target is excited. It is shown that both the level coupling for the entrance channel, and the different target spin, change the fission cross section.

show abstract

“…[16] on depopulation of the 180m Ta isomer by fast neutron inelastic scattering, in accordance with the basic ideas of the statistical model. In that work, no preferential population of the ground state was observed, unlike the present case of capture on 178m 2 Hf.…”

Section: Discussionmentioning

confidence: 63%