Browsing by Author "J. Gehlot"

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Evaporation residue cross-section measurements for 30Si+142Ce system
(Elsevier B.V., 2024) Amninderjeet Kaur; A. Kumar; Chetan Sharma; Neha Dhanda; Raghav; N. Madhavan; S. Nath; J. Gehlot; Gonika; Chandra Kumar; P. Sherpa; A. Parihari; Jyoti Pandey; A.K. Gupta; H.P. Sharma; B.R. Behera
Evaporation residue (ER) cross-sections were measured for 30Si+142Ce reaction at laboratory energies in the range of 105 - 132 MeV using the HYbrid Recoil mass Analyzer (HYRA) at IUAC, New Delhi. The transmission efficiency of the HYRA was estimated using the calibration reaction 28Si+142Ce. Sub-barrier fusion enhancement was observed when compared with the one-dimensional barrier penetration model predictions for the present system. To explore the phenomena responsible for sub-barrier fusion enhancement, coupled-channels calculations were performed using the CCFULL code. The effect of couplings and the role of positive Q-value neutron transfer (PQNT) channels on sub-barrier fusion cross-sections were investigated. Coupled-channels calculations were able to reproduce the data by including the coupling in both projectile and target nucleus along with two neutron-transfer channels having positive Q-value. The measured ER cross-sections were compared with the nearby systems to explore the role of deformation of the colliding nuclei. © 2023 Elsevier B.V.
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.
Role of neutron transfer in the sub-barrier fusion cross section in O 18 + Sn 116
(American Physical Society, 2020) Nabendu Kumar Deb; Kushal Kalita; Harun Al Rashid; S. Nath; J. Gehlot; N. Madhavan; Rohan Biswas; Rudra N. Sahoo; Pankaj K. Giri; Amar Das; Tapan Rajbongshi; Anamika Parihari; Niraj K. Rai; Saumyajit Biswas; Khushboo; Amritraj Mahato; B.J. Roy; A. Vinayak; Anjali Rani
Background: In heavy-ion-induced fusion reactions, cross sections in the sub-barrier region are enhanced compared to predictions of the one-dimensional barrier penetration model. This enhancement is often understood by invoking deformation and coupling of the relative motion with low-lying inelastic states of the reaction partners. However, effects of nucleon transfer on fusion below the barrier, especially for the systems having positive Q value neutron transfer (PQNT) channels, are yet to be disentangled completely. Purpose: We intend to study the role of the PQNT effect on the sub-barrier fusion of the O18 + Sn116 system having positive Q value for the two-neutron stripping channel. Also we reflect on the interplay of couplings involved in the system around the Coulomb barrier. Method: The fusion excitation function was measured at energies from 11% below to 46% above the Coulomb barrier for O18 + Sn116 using a recoil mass spectrometer, viz., the Heavy-Ion Reaction Analyser (HIRA). Fusion barrier distributions were extracted from the data. Results from the experiment were analyzed within the framework of the coupled-channels model. Results: Fusion cross sections at energies below the Coulomb barrier showed strong enhancement compared to predictions of the one-dimensional barrier penetration model. The fusion process is influenced by couplings to the collective excitations with coupling to single- A nd two-phonon vibrational states of the target and the projectile respectively. Inclusion of the two-neutron transfer channel in the calculation along with these couplings could reproduce the data satisfactorily. Conclusions: The significant role of PQNT in enhancing the sub-barrier fusion cross section for the chosen system is not observed. It simply reduced the sub-barrier fusion cross section. Therefore, a consistent link between PQNT and sub-barrier fusion enhancement could not be established vividly while comparing the fusion excitation function from this work with the same from other O16,18-induced reactions. This clearly points to the need for more experimental as well as theoretical investigation in this field. © 2020 American Physical Society.
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.