Rotational bands in 152Sm observed following the (α, 2nγ) reaction

Physics Letters B, 1981

The number of bosons deduced from variational calculations of spectra and intrinsic mass quadrupole moments of heavy deformed nuclei are compared with predictions of IBA in the SU(3) limit. The differences between the two suggest the need for including I > 2 bosons in IBA.

Mathematical and Computational Applications, 2007

Since the lowest levels are symmetric under the interchange of neutrons and protons from calculations in the interacting boson approximation IBA-2 model, IBA-1 model space, in which neutron and proton degrees of freedom are not distinguished can be considered as a subspace of the IBA-2 model space. Using the microscopic background of the IBA-2 model, a correspondence can be established between IBA-1 and IBA-2 model space. Since the space of the IBA-1 model can be regarded as a subspace of the IBA-2 model there is a unique way to "Project" the operators of the IBA-2 model onto those of IBA-1. This projection can be carried out by using the Fspin formalism. In the IBA-2, the lowest states are indeed fully symmetric, the calculations with the help of this projection, we explore the energy levels and the electric quadrupole transition probabilities B(E2;I i → I f) and γ-ray E2/M1 mixing ratios for selected transitions of 166-168 Er .Owing to admixtures of non-fully-symmetric states in IBA-2, we renormalized the parameters (ε) and (κ).This is the first time we show that this projection can be applied to some heavier isotopes and the results obtained for 166-168 Er isotopes are reasonably in good agreement with the previous experimental values.

2010

AIP Conference Proceedings, 1997

A beam of charged particles as a tool for non-destructive analysis of the structure and elemental composition of thin-surface layers is frequently used in material investigations. Nuclear methods such as RBS or NRA techniques have a good depth resolution and sufficient mass sensitivity. Many computer programs exist, like the RUMP [see L.R. Doolitle, Nucl. Instr. and Meth. B 9 (1985) 3441 or DVBS [see V. Bob% and D.M. Shirokov, Nucl. Instr. and Meth. B 84 (1994) 4971 codes, for simulation and for analysis of experimental results collected in measurements with beams of charged particles. A new computer code, called BSCAT (BackSCATtering), was created at the Institute of Nuclear Physics to analyze experi.mental spectra and to simulate new experiments. The BSCAT code, written in FORTRAN-77 and partially in C, can work on IBM personal computers or on larger computers such as CONVEX machines. As input for the program both Rutherford and non-Rutherford cross sections can be used and the stopping power function can he calculated by the Ziegler or the Montenegro formula. The program was used in the analysis of complex spectra of backscattered particles. Among other applications the BSCAT code was used for analysis of the spectrum of 2100 keV protons bombarding a thin carbon foil created by the IBAD technique on the surface of a Si (111) single crystal [ '*C(p, p)'*C and 28Si(p, p)28Si resonance].

Pramana, 2005

The interacting boson approximation IBA-1 model space, in which neutron and proton degrees of freedom are not distinguished, can be considered as a subspace of the IBA-2 model space. Using the microscopic background of the IBA-2 model, a correspondence can be established between IBA-1 and IBA-2 model space. Since the space of the IBA-1 model can be regarded as a subspace of the IBA-2 model there is a unique way to 'Project' the operators of the IBA-2 model onto those of IBA-1. This projection can be carried out using the F -spin formalism. In the IBA-2 model, the lowest states are indeed fully symmetric, and using the calculations with the help of this projection, we explore the energy levels and the electric quadrupole transition probabilities B(E2; I i → I f ) and γ-ray E2/M 1 mixing ratios for selected transitions of 162,164,166,168,170 Er. Owing to admixtures of non-fully-symmetric states in IBA-2, we renormalized the parameters (ε) and (κ). This is the first time we show that this projection can be applied to some heavier isotopes and the results obtained for 162,164,166,168,170 Er isotopes are reasonably in good agreement with the previous experimental values.

Physical Review C, 2004

Prompt and delayed ␥ rays from 191,193 Bi have been identified using the recoil-decay tagging, isomer tagging, and recoil gating techniques, resulting in extensive level schemes for both nuclei. Excitation energies of the isomeric 13/ 2 + states have been established and oblate strongly coupled bands built on them have been observed. The nearly spherical 9 / 2 − ground-state bands appear to be crossed by more oblate-deformed lowlying structures. The properties of the bands feeding the 1 / 2 + intruder states indicate some structural change between 193 Bi and 191 Bi. The deformation associated with each of these states has been extracted from total Routhian surface calculations which also reveal the development of prolate minima with decreasing neutron number. B͑M1͒ / B͑E2͒ ratios have been measured for the observed strongly coupled bands in order to resolve the intrinsic excitations. The observed quasiparticle structures in 193 Bi and high-spin isomers both in 193 Bi and 191 Bi are interpreted based on the coupling of the odd proton to the even-even Pb core.

Chiang Mai Journal of Science

The yrast-state bands and E2 transition rates for the even 100-102Ru isotopes are studied in the framework of the interacting boson model (IBM-1). The values of the parameters have been determined using the IBM-1 Hamiltonian which yield the best fit to the available experimental energy levels. The theoretical energy levels have been obtained by Matlap computer program for Ruthenium isotopes with neutron number N= 56 and 58 up to spin-parity 28+ and 16+, respectively. Furthermore, the B(E2) values are calculated and compared with the experimental data. The ratio of excitation energies of the first 4+ and the first 2+ excitated states, R4/2, is also studied for the classification of symmetry of these nuclei. The moment of inertia and the potential energy surface of 100-102Ru isotopes also calculated. Back bending phenomena of those nuclei are studied. The calculated results of yrast energy band and B(E2) values are compared with the previous experimental results and the obtained theor...

ScienceAsia, 2016

In this paper, an interacting boson model (IBM-1) has been used to calculate the low-lying positive parity yrast bands in Hf, W, and Os nuclei for N = 108 neutrons. The systematic yrast level, electric reduced transition probabilities B(E2) ↓, deformation, and quadrupole moments of those nuclei are calculated and compared with the available experimental values. The ratio of the excitation energies of first 4 + and first 2 + excited states, R 4/2 , is also studied for these nuclei. Furthermore, as a measure to quantify the evolution, we have studied systematically the yrast level R = (E2 : L + → (L − 2) + )/(E2 : 2 + → 0 + ) of some low-lying quadrupole collective states in comparison to the available experimental data. The associated quadrupole moments and deformation parameters have also been calculated. Moreover, we have studied the systematic B(E2) values, intrinsic quadrupole moments, and deformation parameters in those nuclei. The moment of inertia as a function of the square of the rotational energy for even atomic numbers Z = 72, 74, 76 and N = 108 nuclei indicates the nature of the back-bending properties. The results of these calculations are in good agreement with the corresponding available experimental data. The analytic IBM-1 calculation of yrast levels and B(E2) values of even-even Hf, W, and Os for N = 108 nuclei were performed in the SU(3) character.

Physical Review C, 2015

Background: Identification of proton-neutron mixed-symmetric one-quadrupole phonon excitations (the 2 + ms states) of atomic nuclei provides information on the isovector part of the residual nucleon-nucleon interaction. It was predicted that the 2 + ms state of particular nuclei close to the U(5) limit of the interacting boson model, in particular 140 Ba, should be considerably populated by α-transfer reactions [C. E. Alonso et al., Phys. Rev. C 78, 017301 (2008)]. Purpose: We aim at the identification of the 2 + ms mixed-symmetry state (MSS) of radioactive 140 Ba and investigate its population by the α-transfer reaction as a suitable tool to selectively populate MSSs and as a potential new signature for its mixed-symmetric character. Method: A γ-ray spectroscopy experiment was performed in inverse kinematics in order to populate the 2 + ms state of 140 Ba by α-transfer from a nat C target on 136 Xe beam ions. The population of the candidate for the 2 + ms state of 140 Ba was measured relative to the population of the 2 + 1 state. Results: The candidate for the 2 + ms state of 140 Ba was populated by α transfer three times weaker than predicted. Another 2 + state that can be ruled out as the MSS was in turn as strongly populated by the α transfer as predicted for the MSS. Conclusions: The relative population of 2 + states by α-transfer cannot serve as a new signature for MSSs, since other 2 + states are also strongly populated. Nevertheless, the substantial population of the MSS candidate of 140 Ba by α transfer qualifies this type of reaction as suitable tool to excite MSSs and study their electromagnetic decay properties.

In this paper , 170-176 Yb isotopes have been studied by using interacting boson model (IBM-1) to determine energy levels and it was classified in two bands the ground state and bata band addition, the square of rotational energy and the moment of inertia values for 170-176 Yb were calculated and compared with the experimental data. The obtained results for 170-176 Yb were reasonably in good agreement with the experimental data .The attestations refer to this isotopes belong to the rotational limit SU(3).