Browsing by Author "T. Trivedi"

Now showing 1 - 14 of 14

Band structure and shape coexistence in 56135Ba79
(American Physical Society, 2010) Suresh Kumar; A.K. Jain; Alpana Goel; S.S. Malik; R. Palit; H.C. Jain; I. Mazumdar; P.K. Joshi; Z. Naik; A. Dhal; T. Trivedi; I. Mehrotra; S. Appannababu; L. Chaturvedi; V. Kumar; R. Kumar; D. Negi; R.P. Singh; S. Muralithar; R.K. Bhowmik; S.C. Pancholi
Excited states of 56135Ba79 at high spins are studied using the reaction Te130(Be9,4n)56135Ba79 at 42.5-MeV beam energy. The earlier known level scheme is extended up to 6.4-MeV excitation energy and (37/2) spin with the addition of several transitions. We have performed polarization asymmetry measurements for some of the strong transitions by using a Clover detector to assign the parity. A comparison of experimental data with the results of tilted axis cranking calculations based on various configurations indicates the coexistence of multiple minima in the triaxial deformation (γ), whereas axial symmetric deformation (ε2) remains constant around 0.09. © 2010 The American Physical Society.
Evidence of antimagnetic rotation in odd-A Cd105
(American Physical Society, 2010) Deepika Choudhury; A.K. Jain; M. Patial; N. Gupta; P. Arumugam; A. Dhal; R.K. Sinha; L. Chaturvedi; P.K. Joshi; T. Trivedi; R. Palit; S. Kumar; R. Garg; S. Mandal; D. Negi; G. Mohanto; S. Muralithar; R.P. Singh; N. Madhavan; R.K. Bhowmik; S.C. Pancholi
The lifetimes of the levels above spin 23/2⊃- in the negative-parity yrast band of Cd105 have been measured using the Doppler shift attenuation method. The obtained B(E2) values are small and show a decrease with an increase in spin. This establishes, for the first time, antimagnetic rotation (AMR) in an odd-A nucleus. An excellent agreement between the theoretical (semiclassical model) and experimental results along with a large I(2)/B(E2) ratio for the states strongly suggests that the structure of the levels beyond spin 23/2⊃- has the character of a twin-shears type AMR band resulting from the coupling of a pair of g9/2 proton holes with aligned h11/2 and (g7/2)2 neutron particles, along with a small contribution from the core rotation. © 2010 The American Physical Society.
Evolution of collectivity and evidence of octupole correlations in Br 73
(American Physical Society, 2019) S. Bhattacharya; T. Trivedi; D. Negi; R.P. Singh; S. Muralithar; R. Palit; I. Ragnarsson; S. Nag; S. Rajbanshi; M. Kumar Raju; V.V. Parkar; G. Mohanto; S. Kumar; D. Choudhury; R. Kumar; R.K. Bhowmik; S.C. Pancholi; A.K. Jain
High-spin states in the Br73 nucleus have been populated via the Cr50(Si28,αp)Br73 fusion evaporation reaction with a beam energy of 90 MeV. The deexciting gamma rays were detected using the Indian National Gamma Array (INGA). Using the γ-γ coincidence technique, two new bands and eight new interconnecting transitions have been added. The strong interconnecting E1 transitions, between positive and negative parity bands, ensure the existence of octupole correlations at low spin. Line shapes have been observed for 17 transitions, which were analyzed by the Doppler-shift attenuation method to determine the lifetime of excited states of the yrast negative parity band and its signature partner band along with the positive parity band. The deduced transitional quadrupole moments Qt for the ground state band decrease with increasing spin, with their values ranging from 2.88 to 1.00 eb. A similar trend in the quadrupole moment has also been observed for the signature partner as well as for the positive parity band. This decrease in Qt with increasing spin for these bands is interpreted in terms of the cranked Nilsson-Strutinsky model and total Routhian surface calculations, which indicate possible band termination at higher spin. © 2019 American Physical Society.
High spin spectroscopy and shears mechanism in In107
(American Physical Society, 2010) D. Negi; T. Trivedi; A. Dhal; S. Kumar; V. Kumar; S. Roy; M.K. Raju; S. Appannababu; G. Mohanto; J. Kaur; R.K. Sinha; R. Kumar; R.P. Singh; S. Muralithar; A.K. Bhati; S.C. Pancholi; R.K. Bhowmik
High spin states of In107 have been investigated using the reaction Mo94(O16,p2n)In107 at a beam energy of 70 MeV. A total of 62 new γ transitions have been placed in the level scheme and several ΔI=1 sequences and one ΔI=2 sequence have been found. Lifetime measurements using the Doppler-shift attenuation method (DSAM) have been carried out for band states of ΔI=1 and ΔI=2. A decreasing trend of B(M1) strengths with increasing spin deduced for the ΔI=1 band indicates the presence of a shears mechanism. The experimental data for this band are compared with the tilted axis cranking (TAC) calculations. The ΔI=2 band has been found to be a deformed band with β2~0.2. © 2010 The American Physical Society.
Indian National Gamma Array at Inter University Accelerator Centre, New Delhi
(2010) S. Muralithar; K. Rani; R. Kumar; R.P. Singh; J.J. Das; J. Gehlot; K.S. Golda; A. Jhingan; N. Madhavan; S. Nath; P. Sugathan; T. Varughese; M. Archunan; P. Barua; A. Gupta; M. Jain; A. Kothari; B.P.A. Kumar; A.J. Malyadri; U.G. Naik; Raj Kumar; Rajesh Kumar; J. Zacharias; S. Rao; S.K. Saini; S.K. Suman; M. Kumar; E.T. Subramaniam; S. Venkataramanan; A. Dhal; G. Jnaneswari; D. Negi; M.K. Raju; T. Trivedi; R.K. Bhowmik
A 4π multi-detector gamma-ray spectrometer named the Indian National Gamma Array (INGA) has been set up at the Inter University Accelerator Centre, New Delhi, for nuclear structure studies. The array is designed to incorporate twenty four Compton-suppressed Clover germanium detectors with a total photopeak efficiency ∼5%. The spectrometer along with sub-systems developed in-house like, mechanical support structure, high voltage power supplies, automatic liquid nitrogen filling system, front-end electronics and data acquisition system are described. The mechanical support structure facilitates the use of the Clover Germanium array with a recoil mass separator. The array has been used in a number of nuclear spectroscopic investigations. The in-beam and off-beam performance of the array are reported. © 2010 Elsevier B.V.
Indian National Gamma Array at IUAC
(Institute of Physics Publishing, 2011) S. Muralithar; K. Rani; R.P. Singh; R. Kumar; J.J. Das; J. Gehlot; K.S. Golda; A. Jhingan; N. Madhavan; S. Nath; P. Sugathan; T. Varughese; M. Archunan; P. Barua; A. Gupta; M. Jain; A. Kothari; B.P.A. Kumar; A.J. Malyadri; U.G. Naik; Raj Kumar; Rajesh Kumar; J. Zacharias; S. Rao; S.K. Saini; S.K. Suman; M. Kumar; E.T. Subramaniam; S. Venkataramanan; A. Dhal; G. Jnaneswari; D. Negi; M.K. Raju; T. Trivedi; R.K. Bhowmik
Indian National Gamma Array (INGA) is a 4π multi-detector gamma-ray spectrometer based on twenty four Compton-suppressed Clover Germanium detectors with a total photo peak efficiency ∼ 5 %. INGA was designed to perform high resolution gamma-ray spectroscopy to study nuclear structure at high spins with stable ion beams at Inter University Accelerator Centre (IUAC). Description of the facility and performance of the array are presented in this paper. Since its commissioning, a number of nuclear spectroscopic investigations have been carried out using the array.
Investigation of an intruder band in 45 Sc via coulomb excitation ∗
(Jagellonian University, 2019) M. Matejska-Minda; R. Kumar; P.J. Napiorkowski; M. Saxena; S. Dutt; A. Agarwal; I. Ahmed; S. Bhattacharya; A. Jhingan; J. Kaur; M. Kicińska-Habior; M. Kumar; S. Kumar; D. Kumar; V. Nanal; R. Palit; N.K. Rai; M. Shuaib; A. Sood; A. Stolarz; T. Trivedi; A.K. Tyagi; R.K. Bhowmik; H.J. Wollersheim
In order to gain further information on the electromagnetic properties of the low-lying states in 45 Sc, a Coulomb excitation measurement was carried out at the IUAC, New Delhi. The 45 Sc target nuclei were Coulomb excited by the 70 MeV 32 S beam from the 15UD tandem accelerator. The γ-rays depopulating Coulomb excited states in 45 Sc were detected by four Clover detectors in coincidence with the forward scattered ions. The main aim of the experiment was to determine the B(E3; 7/2 − → 3/2 + ) and B(E3; 7/2 − → 5/2 + ) transition probabilities, as well as the transitional electromagnetic matrix elements for low-lying intruder states. © 2019 Jagellonian University. All Rights Reserved.
Level structures of 96Tc and their microscopic description
(Institute of Physics, 2024) A.K. Rana; S. Sihotra; H.P. Sharma; V. Singh; G.H. Bhat; S. Jehangir; J.A. Sheikh; N. Rather; Kuldeep; N. Singh; R.K. Bhowmik; R. Kumar; R.P. Singh; S. Muralithar; Pooja Chauhan; Dalip Singh Verma; T. Trivedi; S. Kumar; R. Palit; D. Mehta
High spin states in the 96Tc nucleus were populated in the 75As(28Si, 4p3n) fusion-evaporation reaction at E lab = 120 MeV and the de-excitations were investigated through in-beam γ-ray spectroscopic techniques using indian national gamma array spectrometer consisting of 18 clover Ge detectors. The present level scheme of the 96Tc nucleus has been extended substantially with the addition of about forty five new γ transitions. The level structures in 96Tc have been established up to excitation energy ∼10 MeV and angular momentum ∼25ℏ. Level structures of 96Tc nucleus are discussed in the framework of triaxial projected shell model calculations. © 2024 IOP Publishing Ltd
Lifetime measurement of high spin states in 75Kr
(Elsevier, 2010) T. Trivedi; R. Palit; D. Negi; Z. Naik; Y.-C. Yang; Y. Sun; J.A. Sheikh; A. Dhal; M.K. Raju; S. Appannababu; S. Kumar; D. Choudhury; K. Maurya; G. Mahanto; R. Kumar; R.P. Singh; S. Muralithar; A.K. Jain; H.C. Jain; S.C. Pancholi; R.K. Bhowmik; I. Mehrotra
The lifetimes of high spin states of 75Kr have been determined via 50Cr (28Si, 2pn) 75Kr reaction in positive parity band using the Doppler-shift attenuation method. The transition quadrupole moments Qt deduced from lifetime measurements have been compared with 75Br. Experimental results obtained from lifetime measurement are interpreted in the framework of projected shell model. © 2010 Elsevier B.V. All rights reserved.
Revised lifetime of the 11/2- state in 45Sc via coulomb excitation
(Jagellonian University, 2020) M. Matejska-Minda; P.J. Napiorkowski; R. Kumar; M. Saxena; S. Dutt; A. Agarwal; I. Ahmed; S. Bhattacharya; A. Jhingan; J. Kaur; M. Kicińska-Habior; M. Kumar; S. Kumar; D. Kumar; V. Nanal; R. Palit; N.K. Rai; M. Shuaib; A. Sood; A. Stolarz; T. Trivedi; A.K. Tyagi; R.K. Bhowmik; H.J. Wollersheim
A Coulomb-excitation measurement to study low-energy electromagnetic properties of 45Sc has been performed at the IUAC facility in New Delhi, India using a 70 MeV 32S projectile from the 15UD tandem accelerator. The preliminary value of the reduced transition probability B(E2; 11/2- → 7/2-) and the resulting lifetime for the 11/2- state at 1237 keV were determined using the GOSIA code. © 2020 Jagellonian University. All rights reserved.
Shape evolution in odd-A 137 Pm
(Springer New York LLC, 2012) A. Dhal; R.K. Sinha; D. Negi; T. Trivedi; M.K. Raju; D. Choudhury; G. Mohanto; S. Kumar; J. Gehlot; R. Kumar; S. Nath; S.S. Ghugre; R.P. Singh; J.J. Das; S. Muralithar; N. Madhavan; J.B. Gupta; A.K. Sinha; A.K. Jain; I.M. Govil; R.K. Bhowmik; S.C. Pancholi; L. Chaturvedi
The odd mass nucleus 137Pm has been studied to high spins through the 109Ag(32S, 2p2n)137Pm reaction at an incident beam energy of 150 MeV. The de-exciting γ-rays were detected using an array of 18 Compton suppressed clover detectors. The level scheme of 137Pm has been extended up to Jπ = 43/2- and excitation energy of Ex ≅ 6 MeV with the observation of 42 new gamma transitions. The linear polarization (IPDCO) measurements for the γ-ray transitions have been done for the first time. The spin and parity assignments for most of the reported levels have been made using these results and the coincidence angular anisotropy (RDCO) measurements. The nuclear shape evolution is discussed in the light of Total Routhian Surface (TRS) and Cranked Shell Model (CSM) calculations. © 2012 SIF, Springer-Verlag Berlin Heidelberg.
Shape evolution of the highly deformed Kr75 nucleus examined with the Doppler-shift attenuation method
(American Physical Society, 2009) T. Trivedi; R. Palit; D. Negi; Z. Naik; Y.-C. Yang; Y. Sun; J.A. Sheikh; A. Dhal; M.K. Raju; S. Appannababu; S. Kumar; D. Choudhury; K. Maurya; G. Mahanto; R. Kumar; R.P. Singh; S. Muralithar; A.K. Jain; H.C. Jain; S.C. Pancholi; R.K. Bhowmik; I. Mehrotra
High-spin states of the Kr75 nucleus have been populated via the Cr50(Si28,2pn)Kr75 reaction at an incident beam energy of 90 MeV. Lifetimes of nine states up to spin I=33/2 for the positive-parity band and seven states up to I=27/2 for the negative-parity band have been measured using the Doppler-shift attenuation method. The deduced transition quadrupole moments Qt of these bands have been compared to the projected shell-model calculations to gain insight into the evolution of collectivity for the two experimentally studied bands in Kr75. © 2009 The American Physical Society.
Shears mechanism in 109In
(American Physical Society, 2012) D. Negi; T. Trivedi; A. Dhal; S. Kumar; V. Kumar; S. Roy; M.K. Raju; S. Appannababu; G. Mohanto; J. Kaur; R.K. Sinha; D. Choudhury; D. Singh; R. Kumar; R.P. Singh; S. Muralithar; A.K. Bhati; S.C. Pancholi; R.K. Bhowmik
High spin states of 109In were investigated using the reaction 96Zr(19F, 6n)109In at a beam energy of 105 MeV. New level sequences have been found in this nucleus. In an earlier known band, the ordering of some of the transitions have been changed and assigned a three-quasiparticle π(g9/2) -1 âŠ - ν[h11/2(d5/2/g7 /2)] configuration. Similar three-quasiparticle bands have also been found earlier in lighter mass 105In and 107In nuclei. Systematics of these bands in 105In, 107In, and 109In nuclei are discussed in the present work within the framework of the tilted axis cranking model. © 2012 American Physical Society.
STRUCTURE OF LOW-SPIN STATES IN45Sc STUDIED VIA COULOMB EXCITATION
(Jagiellonian University, 2024) M. Matejska-Minda; P.J. Napiorkowski; K. Sieja; P. Bednarczyk; T. Abraham; A. Agarwal; I. Ahmed; S. Bhattacharya; R.K. Bhowmik; D.T. Doherty; S. Dutt; K. Hadyńska-Klęk; J. Iwanicki; A. Jhingan; J. Kaur; M. Kicińska-Habior; M. Kisieliński; M. Komorowska; M. Kowalczyk; M. Kumar; R. Kumar; S. Kumar; D. Kumar; A. Maj; T. Marchlewski; P. Matuszczak; V. Nanal; A. Nannini; M. Palacz; R. Palit; L. Próchniak; N.K. Rai; M. Rocchini; M. Saxena; W. Satuła; M. Shuaib; M. Siciliano; A. Sood; J. Srebrny; A. Stolarz; J. Styczeń; T. Trivedi; A.K. Tyagi; B. Wasilewska; H.J. Wollersheim; K. Wrzosek-Lipska; M. Zielińska
The electromagnetic structure of45Sc at low excitation energy was investigated via low-energy Coulomb excitation at the Heavy Ion Laboratory (HIL) of the University of Warsaw and at the Inter-University Accelerator Centre (IUAC) in New Delhi. A set of reduced E2, E3, and M1 matrix elements was extracted from the collected data using the GOSIA code. The reduced transition probability B(E2; 11/2− → 7/2−) has been determined, allowing us to deduce the lifetime of the 11/2− state at 1237 keV. In addition, the upper limit on the reduced transition probability B(E3; 7/2− → 5/2+) has been determined for the first time. New large-scale shell-model and beyond-mean-field calculations were performed to interpret the structure of this nucleus. © 2024 Jagiellonian University. All rights reserved.