Search

High spin states of 88Zr were populated with 80Se(l3C, 5n) fusion evaporation reaction. A thin target as well as Au backed target were used in two different experiments for the present study. Excited levels of 88Zr have been observed up to spin ~20ħ and an excitation energy of ~10 MeV. Spin and parity of most of the states have been determined from directional correlation and polarization measurements. The level scheme was substantially extended with the addition of a number of high spin states and transitions. The comparison of the measured levels of 88Zr with large shell model calculations based on the full unrestricted f5/2Pg9/2 model space established the dominance of shell-model excitation up to the highest observed spin. [ABSTRACT FROM AUTHOR]

High spin states in 112In were investigated using the 100Mo(16O, p3n) reaction at 80 MeV. The excited level has been observed up to 5.6 MeV excitation energy and spin ∼207&hstroke; with the level scheme showing three dipole bands. Polarization and lifetime measurements were carried out for the dipole bands. Tilted axis cranking model calculations were performed for different quasiparticle configurations of this doubly odd nucleus. Comparison of the calculations of the model with the B(M 1) transition strengths of the positive- and negative-parity bands firmly established their configurations. [ABSTRACT FROM AUTHOR]

The High-spin states in 195 Tl, populated through the 185,187 Re( 13 C, xn) fusion evaporation reaction at the beam energy of 75 MeV, were studied using the Indian National Gamma Array (INGA). More than 50 new γ transitions have been placed in the proposed level scheme which is extended up to the excitation energy of ≈ 5.6 MeV and spin = 22.5 ħ . Two pairs of degenerate bands based on two different quasi-particle configurations have been identified in this nucleus indicating the first observation of such bands in an odd- A nucleus in A ∼ 190 region and signify the first evidence of multiple chiral bands in a nucleus in this region. The total Routhian surface calculations predict triaxial shapes for both the configurations and thereby, support the experimental observation. The importance of multiple neutron holes in the i 13 / 2 orbital and the stability of shapes for these two configurations have been discussed. [ABSTRACT FROM AUTHOR]

The high-spin states in 86 Sr nucleus were populated using the 76 Ge( 13 C, 3n) reaction at a beam energy of 45 MeV. The γ – γ and γ – γ – γ coincidence measurements were used to establish the level scheme up to 10.9 MeV excitation energy and spin I π = 19 + . In our preliminary results reported earlier, a positive-parity dipole ( Δ I = 1 ) band based on the 6878-keV level having M1 γ -ray transitions was identified. In the present work, the γ -rays and their sequence have been established for this band. The band may have a magnetic rotational character. The spin-parity of the levels were assigned by measuring the Directional Correlations of the Oriented (DCO) nuclei and the polarization asymmetry. The polarization measurements were performed for the first time for the γ -ray transitions in this nucleus. The experimental band structures were compared with the shell-model calculations using two recent effective interactions, JUN45 and jj44b in the 1 p 3 / 2 , 0 f 5 / 2 , 1 p 1 / 2 , 0 g 9 / 2 model space. From the Tilted-Axis Cranking (TAC) calculations, the 4-qp π ( g 9 / 2 ) 2 ⊗ ν ( g 9 / 2 ) − 2 configuration is suggested for the lower-part of the ( Δ I = 1 ) band up to spin I π = 16 + and the 6-qp π [ ( g 9 / 2 ) 2 ( f 5 / 2 ) 1 ( p 1 / 2 ) 1 ] ⊗ ν ( g 9 / 2 ) − 2 configuration for the upper-part of the band. [ABSTRACT FROM AUTHOR]

High spin states in 105Cd were studied using 92Mo(16O, 2pn)105Cd reaction at an incident beam energy of 75 MeV. The level scheme of 105Cd has been observed up to Jπ = (47/2-) and excitation energy ~10.8MeV with the addition of 30 new γ transitions to the previous work. Spin and parity for most of the reported levels are assigned from the directional correlation orientation (DCO) ratios and linear polarization measurements. The microscopic origin of the investigated band structures is discussed in the context of triaxial projected shell model (TPSM). The energies of observed positive- and negative-parity bands agree with the predictions of the TPSM by considering triaxial deformation for the observed excited band structures. The shape evolution with increasing angular momentum is explained in the framework of cranked shell model (CSM) and the total Routhian surface (TRS) calculations. [ABSTRACT FROM AUTHOR]

The article offers information on a study related to the observation of high-spin dipole structures of 143Europium (Eu) through fusion-evaporation reaction and clover detector array. Topics discussed include the use of Doppler shift attenuation method to measure dipole bands, magnetic rotational character of the bands and the role of axis cranking model for calculating bands. Other topic discussed include use of unpolarized radioactive Eu and barium for the study.

The article offers information on a study related to the use of shell-model and tilted axis cranking (TAC) model to calculate high spin (HS) states of 3885strontium (Sr)47. Topics discussed include the use of TAC to understand magnetic rotation (MR) phenomenon at HS, quasiparticle configuration at HS and spin-parity assignment of nuclear levels. Other topic discussed include determination of electromagnetic character of nuclear transitions for the study.

The article presents brief information on spectroscopic properties of nuclei in the upper-sd shell of energy orbit. It talks about study of high spin states of sulphur isotopes populated through aluminum isotopes reaction using the Indian National Gamma Array (INGA) facility in India. Information on multipolarity of the γ-ray transition, levels with excitation energy, is also offered.

High spin states of 142Sm have been investigated using the fusion-evaporation reaction 116Cd (31P, p4n) at beam energy 148 MeV using the Indian National Gamma Array (INGA). Approximately sixty new gamma transitions have been placed in the proposed level scheme, which has been extended up to Ω12.5 MeV. Several band-like structures including one dipole band and three quadrupole bands have been observed in the proposed level scheme. Lifetimes of several levels in the dipole band and quadrupole bands have been measured using doppler shift attenuation method (DSAM). The deduced B(M1) values for the dipole band have been compared with the semiclassical shears mechanism with the principle axis cranking (SPAC) model, and the dipole band has been interpreted as a magnetic rotational band. Comparisons between the experimental characteristics and cranked Nilsson-Strutinsky (CNS) calculations for the observed quadrupole bands indicate that these bands have been formed on the triaxial deformed shape of 142Sm. [ABSTRACT FROM AUTHOR]

The high spin structure of 20IT1 has been studied by y-ray spectroscopic method using the 198Pt(7Li,4n)201TI reaction at 45 MeV beam energy. The level scheme of 201TI has been considerably extended through the observation of 31 new transitions. Several new band structures have been established. The 9/2~ oblate band has been significantly extended beyond the particle alignment frequencies. The band structures and the other excited states have been compared with the neighboring odd-A TI isotopes and with the even-even core nucleus 200Hg. The total Routhian surface calculations have been performed to study the deformation and shape changes as a function of spin in this nucleus. [ABSTRACT FROM AUTHOR]

High spin states in 135La have been investigated using the 128Te(11B,4n)135La reaction at a beam energy of 50.5 MeV using the Indian National Gamma Array (INGA). The level scheme has been confirmed and extended both for low and high spin states with the observation of several new transitions. The Directional Correlations of Oriented states (DCO) ratios and linear polarization measurements have been performed to assign spin-parity for most of the reported γ transitions. A new positive parity band has been observed and identified as a decoupled band (ΔI=2). Two negative parity dipole bands (ΔI=1) have been established and for one of the dipole bands the crossover E2 transitions have been identified for the first time. On the basis of the Tilted Axis Cranking (TAC) calculations, a three quasiparticle (qp) π(h11/2)¹⊗ν(h11/2)-2 configuration and 5qp π(h11/2)¹(g7/2/d5/2)²⊗ν(h11/2)-2 configuration have been assigned to these two dipole bands. The comparison with experimental observables supports the configuration assignments for both the dipole bands. [ABSTRACT FROM AUTHOR]

The high spin states in the odd-odd 194T1 nucleus have been studied by populating them using the 185,187Re(13C, xn) reactions at a beam energy of 75 MeV. A &ggr;-&ggr; coincidence measurement has been performed using the INGA array with a digital data acquisition system to record the time-stamped data. Definite spin-parity assignment of the levels was made from the DCO ratio and the IPDCO ratio measurements. The level scheme of 194T1 has been extended up to 4.1 MeV in excitation energy and includes 19 new &ggr;-ray transitions. The &pgr;h9/2 ⊗ vi13/2 band, in the neighboring odd-odd T1 isotopes, show very similar properties in both experimental observables and calculated shapes. Two new band structures, with six-quasiparticle configuration, have been observed in 194T1. One of these bands has the characteristics of a magnetic rotational band. Cranked shell model calculations, using a deformed Woods-Saxon potential, have been performed to obtain the total Routhian surfaces in order to study the shapes of the bands and the band crossing in 194T1. A semiclassical formalism has been used to describe the magnetic rotational band. [ABSTRACT FROM AUTHOR]

High-spin states in 122I have been investigated using the 116Cd(11B,5n)122I reaction at a beam energy of 65 MeV and y-ray coincidence events were recorded with the ENGA spectrometer. The level scheme of 122I has been extended up to spin I = 30. Experimental features, such as band-crossing frequencies, aligned angular momenta, signature splitting, and B(Ml)/B(E2) ratios have been used for configuration assignments to low-energy band structures. Maximally aligned states involving all eight particles outside the 114Sn core and states with one particle antialigned have been identified. Cranked Nilsson-Strutinsky calculations have been used to interpret high-spin structures. [ABSTRACT FROM AUTHOR]