Band structures of the 123Cs nucleus (original) (raw)

Band structure of the Cs-123 nucleus

Band structures of the 123 Cs nucleus have been investigated using the 100 Mo( 28 Si, p4n) reaction at a beam energy of 130 MeV. The previously observed rotational bands based on πh 11/2 , πg 7/2 and πg 9/2 orbitals have been extended. The excitation energies of these bands have been established with the help of interband transitions and those connecting to the low-energy levels established from the β + /EC decay of 123 Ba (T 1/2 = 2.7 m). The bandhead of the πg 9/2 band at the 328.1 keV (I π = 9/2 + ) is proposed to be isomeric following arguments based on the intensity balance of the feeding and de-exciting γ transitions. New multiquasiparticle bands based on πh 11/2 ⊗ νh 11/2 ⊗ νg 7/2 , πg 7/2 ⊗ π(h 11/2 ) 2 and πg 7/2 ⊗ π(h 11/2 ) 2 ⊗ ν(h 11/2 ) 2 configurations have been identified.

Rotational structures in the 125Cs nucleus

The European Physical Journal A, 2006

The collective band structures of the 125 Cs nucleus have been investigated by in-beam γ-ray spectroscopic techniques following the 110 Pd (19 F, 4n) reaction at 75 MeV. The previously known level scheme, with rotational bands built on πg 7/2 , πg 9/2 and πh 11/2 orbitals, has been extended and evolves into bands involving rotationally aligned ν(h 11/2) 2 and π(h 11/2) 2 quasiparticles. A strongly coupled band has been reassigned a high-K πh 11/2 ⊗νg 7/2 ⊗νh 11/2 three-quasiparticle configuration and a new side band likely to be its chiral partner has been identified. Configurations assigned to various bands are discussed in the framework of Principal/Tilted Axis Cranking (PAC/TAC) model calculations. PACS. 21.10.Re Collective levels-23.20.Lv γ transitions and level energies-21.60.-n Nuclear-strucutre models and methods-27.60.+j 90 ≤ A ≤ 149

Level structure of 123Cs observed from 123Ba decay and described using the IBFM and CQPC models

The European Physical Journal A, 2000

The decay of 123 Ba to 123 Cs has been studied with mass-separated sources. Singles spectra of γ-rays, X-rays and conversion electrons as well as γ − γ − t, γ − e − − t, and X − e − − t coincidences were recorded. A level scheme of 123 Cs has been constructed including 26 new excited states and 82 transitions. The existence of a I π = 11/2 − , T 1/2 = 1.7 s isomer, bandhead of the h 11/2 band, is confirmed. Its excitation energy equals 156.3 keV. A new T 1/2 = 114 ns isomer has been established at 232 keV using the in-beam recoil catcher technique. It is assigned to the I π = 9/2 + bandhead of the πg 9/2 band. Collective bands based on the 1/2 + ground state and first 3/2 + excited state are proposed. The level structure is described in the frame of the interacting boson-fermion and core-quasiparticle coupling models.

Collective structures of the 131Cs nucleus

The European Physical Journal A, 2005

The collective structures of 131 Cs have been investigated by in-beam γ-ray spectroscopic techniques following the 124 Sn (11 B, 4n) reaction at a beam energy E lab = 57 MeV. The previously established rotational bands, built on πg 7/2 , πd 5/2 and the unique-parity πh 11/2 orbitals, have been extended and evolve into new bands involving rotationally aligned ν(h 11/2) 2 and π(h 11/2) 2 quasiparticles. In addition, a new multiquasiparticle band based on the πg 7/2 ⊗νg 7/2 ⊗νh 11/2 configuration has also been observed. Theoretical interpretations for the assigned configurations are discussed in the framework of Total Routhian Surface (TRS) and Tilted Axis Cranking (TAC) model calculations. TAC model calculations predict a decrease in the B(M 1) values with increasing rotational frequency for the πg 7/2 /πd 5/2 ⊗ ν(h 11/2) 2 and πh 11/2 ⊗ ν(h 11/2) 2 bands, thus indicating a magnetic rotation character for these bands. PACS. 21.10.Re Collective levels-23.20.Lv γ transitions and level energies-21.60.-n Nuclear structure models and methods-27.60.+j 90 ≤ A ≤ 149

Nuclear structure studies of 123Te with (n, γ) and (d, p) reactions

Te were investigated in the range up to 3 MeV excitation energy by (n, γ ) and (d, p) reactions. Over 120 levels and about 140 γ -transitions were established most of them for the first time. The states below 2 MeV with the most complete spectroscopic information were interpreted in terms of the Interacting Boson-Fermion Model (IBFM). Unified treatment of both positive-and negative-parity states is achieved with constant parameters of the boson-fermion interaction for the whole chain of Te isotopes. Excitation energies, electromagnetic transition rates, γ -branchings and spectroscopic factors are discussed in connection with their possible structure. A family of low-spin negative-parity states has been identified and understood within the IBFM framework, thus proving their antialigned origin.

Rotational bands in the doubly odd nucleus 134Pr

Nuclear Physics A, 1996

The band structures of the doubly odd '"Pr nucleus has been investigated via the '19Sn( 19F,4n) 'j4Pr and "'Pd( "Si,p3n) lWPr reactions at beam energies of 87 and 130 MeV, respectively. The three previously known rotational bands based on the 7r[541]3/2-(a=?~l/2)@~[514]9/2-and ~[413]5/2+@~[514]9/2-configurations have been extended to higher spins. The difference of M 2ti in the experimental alignment of the bands based on the signature partners of the [ 541]3/2-h11j2 proton orbital is discussed in terms of shape coexistence and coupling with the y-phonon but no consistent interpretation can be found. A new band consisting of quadrupole transitions has also been identified and linked unambiguously to the low-lying levels of the yrast band. Total routhian surface and cranked shell model calculations suggest a ( rrhll/:! )3&W [ 530 ] l/2-configuration for this band. The experimental ratios of reduced transition probabilities B(M1) lB(E2) of the various rotational structures are compared to the theoretical values obtained from a semiclassical model and from the two-particle plus triaxial-rotor model. Nuclear reactions '19Sn( 19F,4n), E = 87 MeV, 110Pd(2sSi,p3n), E = 130 MeV, measured E,, I,, DC0 ratios, W-coincidence, y-multiplicity. 134Pr deduced levels, J, ?r, y-branching, B(A) ratios, experimental routbians, aligned angular momenta. Enriched targets, HPGe detectors, BGO suppression shields, 4?r-BGO ball. Total routhian surface calculations, comparison with cranked shell model, semiclassical model and two-particle plus triaxial-rotor calculations.

Multiple band structures ofCs131

Physical Review C, 2008

Excited states in 131 Cs were investigated through in-beam γ-ray spectroscopic techniques following its population in the 124 Sn(11 B, 4n) fusion-evaporation reaction at a beam energy of 46 MeV. The previously known level scheme has been substantially extended up to ∼9 MeV excitation energy and 49/2h spin with the addition of seven new band structures. The present level scheme consisting of 15 bands exhibits a variety of collective features in this nucleus at intermediate spin. The excitation energies of the observed levels in different bands and the corresponding ratios of transition strengths, i.e., B(M1)/B(E2), have been compared with the results of projected deformed Hartree-Fock calculations based on various quasiparticle configurations. A strongly coupled band has been reassigned a high-K three-quasiparticle πh 11/2 ⊗ ν(h 11/2 d 3/2) configuration based on the properties of this band and that of its new coupled side band. The configurations of these bands are also discussed in the framework of tilted-axis cranking model calculations and the systematics of the odd-A Cs isotopes. Additional three energetically closely placed coupled bands have been assigned different unpaired three-quasiparticle configurations. γ-vibrational bands coupled to the πh 11/2 and πg 7/2 single-particle configurations have been reported in this nucleus. Observation of new E1 transitions linking the opposite-parity πh 11/2 and πd 5/2 bands provides fingerprints of possible octupole correlations.

Collective band structures and particle alignments in 124Ba, 125Ba and 125Cs

Nuclear Physics A, 1988

High-spin states of lz4Ba, "'Ba and '*'Cs have been populated in the reactions "'Cd+ "0 at 80 MeV and 96Zr+ 34S at 160 MeV and studied using nuclear spectroscopy techniques. Several bands have been established in lZ4Ba and previously known band structures in "'Ba and "'Cs extended up to (y-) levels. Results concerning crossing frequencies and quasiparticle configurations are deduced from experimental routhians and aligned angular momenta. We propose that the two positive-parity bands in lz4Ba are generated by h11,2 proton and hl,,z neutron alignments and the three negative-parity bands by the coupling of h,,,*, g,,* neutrons and h,l,Z, g,,, or 89/Z protons. NUCLEAR REACTIONS 'loCd('sO, X), E = 80 MeV; s6Zr(34S, X), E = 160 MeV, E measured E,, I,, yy-coin, linear polarization. '24,'25Ba, lz5Cs deduced levels, J, r, routhians, alignment.

Spectroscopy of the deformed 126 Ce nucleus

The European Physical Journal A - Hadrons and Nuclei, 2003

The even-even nucleus 126 Ce was studied via in-beam γ-ray spectroscopy using the 40 Ca + 92 Mo reaction at 190 MeV. Five bands were observed, one of them being identified for the first time. New connecting transitions were identified between the bands, which lead to new spin assignments. The bands are discussed in the framework of the IBM + broken pairs model.

Rotational bands in the doubly odd 130 Cs nucleus

European Physical Journal A, 2001

The band structures built on the 5- isomeric state ( T 1/2 = 3.46 m) in the doubly odd 130Cs nucleus have been established up to I = 24? via the 124Sn(11B, 5n)130Cs reaction. The previously observed bands based on the πh 11/2⊗νh 11/2, πg 7/2⊗νh 11/2 and πd 5/2⊗νh 11/2 configurations and a positive-parity side band with multiple connections to the α = 0 signature partner of the yrast πh 11/2⊗νh 11/2 band have been extended to higher spins. A new band based on the πh 11/2⊗νg 7/2 configuration is observed. The yrast πh 11/2⊗νh 11/2 band exhibits anomalous signature splitting whose magnitude decreases up to spin 15 and then increases without restoring the normal signature splitting.