Investigation of α-decay of 148Sm resonance states

doi:10.1016/0375-9474(72)90196-0

Nuclear Physics A

Volume 188, Issue 1, 19 June 1972, Pages 212-224

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Abstract

By means of two large multisectional grid ionization chambers the yield of the ¹⁴⁷Sm (n, α)¹⁴⁴Nd reaction in the neutron energy interval E_n ≈ 0–230 eV was measured. The α-particle spectra of the decay of 14 resonances were obtained. The values of the total α-widths or their upper limits were calculated for 24 resonances. The partial α-widths of transitions to the ground and two first excited levels of the final nucleus and the spin of 10 resonances are given. A comparison of the partial and total α-widths with statistical-model predictions was made. The prediction of the α-width distribution is reasonably consistent with the experimental one. This may be regarded as a confirmation of the Porter-Thomas assumptions concerning the distribution of partial α-widths and the independence of fluctuations of the reduced α-widths in the individual exit channels. There was made an attempt to interpret some of the results obtained and their relationship to decay characteristics on the basis of the semi-microscopic description of high excited states proposed by V.G. Soloviev.

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Cited by (23)

Measurement of cross sections for the 147Sm(n, α)144Nd reaction at 5.0 and 6.0 MeV
2009, Applied Radiation and Isotopes
Cross sections of the ¹⁴⁷Sm(n, α)¹⁴⁴Nd reaction were measured at En=5.0 and 6.0 MeV. A twin gridded ionization chamber was used as a charged particle detector and two large area ¹⁴⁷Sm₂O₃ samples placed back to back were employed. Experiments were performed at the 4.5 MV Van de Graaff accelerator of Peking University. Neutrons were produced through the D(d, n)³He reaction with a deuterium gas target. Absolute neutron flux was determined by a small ²³⁸U fission chamber. Present cross-section data are compared with existing results of evaluations and measurements.
Total α-widths of neutron resonances of 147Sm and 149Sm
1976, Nuclear Physics, Section A
An investigation of the (n, α) reaction on ¹⁴⁷Sm and ¹⁴⁹Sm isotopes was performed in the energy range from 0 up to 400 eV and to 100 eV, respectively, using a multisectional proportional chamber. Values for the total α-widths or their upper limits were obtained for about 90 resonances. A comparison has been drawn between the obtained average α-widths and those predicted by optical and cluster models. In the case of ¹⁴⁹Sm, for resonances with spin 4⁻ the total α-width distribution was observed to be much narrower than expected from statistical theory. We failed to find a correlation between neutron and total α-widths.
The (n<inf>th</inf>, α) reaction on 147Sm, 151, 153Eu and Yb isotopes
1974, Nuclear Physics, Section A
The (n, α) reaction has been studied using the highly pure thermal neutron beam from the 87m curved neutron guide at the Grenoble high flux reactor. The ¹⁴⁷Sm(n, α)¹⁴⁴Nd reaction showed up five lines corresponding to the ground and the first four excited states of the final nucleus. It is shown that ≈53 % of the 581 μb (n, α) cross section comes from the neutron capture by a bound level of the ¹⁴⁸Sm compound nucleus. The 8.7 ± 3 μb cross section of ¹⁵¹Eu(n, α)¹⁴⁸Pm seems to consist principally of at least two lines corresponding to the ground and the second excited states of ¹⁴⁸Pm. The ¹⁵³Eu(n, α)¹⁴⁹Pm cross section for thermal neutrons is ≦ 1 μb. The lower limits of (n, α) thermal neutron cross section values on ytterbium isotopes are ≈ 20 to 40 times lower than the published data.
On many-quasiparticle components of the wave functions of neutron resonances
1972, Physics Letters B
The question is raised about the magnitude of many-quasiparticle components of the wave functions of highly excited states. Two possible cases are considered: i) all the components of the wave functions of neutron resonances are small, and ii) these functions contain large many-quasiparticle components. The latter is demonstrated by a model which takes into account quasiparticle-phonon interactions. Some ways of experimental observing large many quasiparticle components are discussed.
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^†: Present address: Institute of Physics, Łodź University, Łodź, Poland.

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Nuclear Physics A

Abstract

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Cited by (23)

Measurement of cross sections for the <sup>147</sup>Sm(n, α)<sup>144</sup>Nd reaction at 5.0 and 6.0 MeV

Total α-widths of neutron resonances of <sup>147</sup>Sm and <sup>149</sup>Sm

The (n<inf>th</inf>, α) reaction on <sup>147</sup>Sm, <sup>151, 153</sup>Eu and Yb isotopes

On many-quasiparticle components of the wave functions of neutron resonances

NICE-Neutron Induced Charged particle Emission

Experimental searches for rare alpha and beta decays