Angular correlation measurements in 155Eu nuclei

Genezini, Frederico A.; Zamboni, Cibele B.; Cruz, M. T. F. da; Zevallos-Chávez, Juan Yury

doi:10.1590/s0103-97332004000500004

Cited by 4 publications

(4 citation statements)

References 1 publication

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“…Other studies using different nuclear reactions, such as 152 Sm(t,α) [4], 153 Eu(t,p) [5] and 154 Sm( 3 He,d) [6] confirmed some of these results and gave a more precise description of the energy levels up to 1.0MeV. Recently Genezini [7] performed angular correlation measurements for several γ cascades where some multipole mixing ratios were extracted suggesting spin and parity for some excited levels, but no additional information related to the beta decay parameters were obtained. Despite all the experimental effort done with 155 Sm, the level scheme is essentially the same proposed by Ungrin et al [3].…”

Section: Introductionmentioning

confidence: 72%

“…The results are presented in Table II and compared with the evaluations from NDS [11]. Also the spin and parity suggested from the recent angular correlation experiment [7] were presented in Table II. The existence of a new transition at 224.8keV, observed in our singles spectra, was confirmed by the 631keV gate in the coincidence data shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

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Decay of 155Sm

et al. 2005

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The beta decay of 155 Sm (T 1/2 ∼ 22min) has been investigated by gamma spectroscopy measurements. The single and coincidence spectra were taken using HPGe detectors with high energy resolution. The energy and relative intensities of 42 γ-rays have been determined, most of them with a better precision than previously. The γ-transitions at 205.7keV and 224.8keV were observed for the first time and 40 of them were confirmed and 39 of them placed in the decay scheme. The present results, together with the results of earlier studies, allows to confirm the energy levels, in the energy range 0.05-1.6MeV, as well as the assignments of spin for most of them.

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Section: Introductionmentioning

confidence: 72%

Section: Resultsmentioning

confidence: 99%

Decay of 155Sm

et al. 2005

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“…The deformation parameters were obtained through a macroscopic-microscopic method, and the proton single particle levels, calculated with realistic Woods-Saxon potential were used as input in a quasiparticle calculation of the first few rotational band heads in the Lipkin-Nogami BCS aproximation. A better agreement is found between the experimental and calculated band heads if compared with previous evaluations and RIPL recommended values.This work is a theoretical support for the interpretation of the experimental results for the multipole mixing ratios of observed electromagnetic transitions between low-energy levels in 155 Eu [1]. In order to explain the experimental results, it was necessary to calculate the energy, angular momentum and parity of the first excited states (E≤ 1MeV).…”

mentioning

confidence: 71%

“…This work is a theoretical support for the interpretation of the experimental results for the multipole mixing ratios of observed electromagnetic transitions between low-energy levels in 155 Eu [1]. In order to explain the experimental results, it was necessary to calculate the energy, angular momentum and parity of the first excited states (E≤ 1MeV).…”

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confidence: 71%

New low-energy levels calculation for 155Eu

Genezini¹,

Zamboni²,

Mesa

et al. 2005

Braz. J. Phys.

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We have revisited the low-energy calculation of odd Z 155 Eu in the frame of a semi-microscopic formalism as a support for the interpretation of the experimental results for the multipole mixing ratios of some electromagnetic transitions. The deformation parameters were obtained through a macroscopic-microscopic method, and the proton single particle levels, calculated with realistic Woods-Saxon potential were used as input in a quasiparticle calculation of the first few rotational band heads in the Lipkin-Nogami BCS aproximation. A better agreement is found between the experimental and calculated band heads if compared with previous evaluations and RIPL recommended values.This work is a theoretical support for the interpretation of the experimental results for the multipole mixing ratios of observed electromagnetic transitions between low-energy levels in 155 Eu [1]. In order to explain the experimental results, it was necessary to calculate the energy, angular momentum and parity of the first excited states (E≤ 1MeV). Due to the fact that the parameters in the potential energy are determined for several nuclei and not for a specific one, the previous calculation was not successful in the description of the first excited states. For example, in the work of Nazarewicz et al. In this work, a new calculation of the ground-state and the low-energy levels in 155 Eu is proposed, using the macroscopic -microscopic method [6]. In this sense, the odd-proton single particle levels in a deformed potential plus residual pairing interaction were calculated in order to describe the 155 Eu lowenergy rotational band heads (with E≤ 1 MeV). The groundstate deformation parameters were obtained by minimizing the total energy [6]; the single particle energy spectra and wave functions for protons and neutrons were calculated in a deformed Woods-Saxon potential [7]. The parameters of the potential for neutrons were obtained from Ref. [8]. For protons, these parameters were adjusted in order to adequately describe the main sequence of angular momentum and parity of the low energy excited levels (band heads), as well as the proton binding energy. The residual pairing interaction was considered in the BCS prescription using the Lipkin-Nogami approximation [9,10]. I. NUCLEAR DEFORMATIONWithin the macroscopic-microscopic method in the Strutinskys formalism, the total energy of the nuclear system as a function of deformation can be expressed as [6]:where ε and α are the set of deformation parameters. The bulk contribution to the total energy comes from the liquid drop model. The shell effects represent smaller variations added to the liquid drop energy E macr . The microscopic portion E micr can be divided into two components: the contribution associated with the shell correction energy and the pairing contribution. In order to obtain the equilibrium deformation parameters (ground-state deformation) the total energy is minimized. As the Cassini ovaloid shape parameterization was used, the adopted deformation parameters were the quadrupole ...

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