1,721,014 research outputs found
Formation and Decay of Exotic Nuclear System using Energy Density Formalism
No full textFinal Report/Executive summaryabstract attachedUniversity Grant Commission, New Delh
Theoretical Study of Decay Processes Observed in Reactions Involving Loosely Bound Projectiles
No full textMSc-Physics-DissertationThe current wave of interest is the reactions where the loosely bound nuclei are involved. These type of reactions involving loosely bound nuclei particularly halo nuclei attracted great interest both from experimentalists and theorists. The reactions with loosely bound nuclei help to find the reaction dynamics and structure of halo nuclei. A reaction does not involve only one process but may evolve variety of decay processes depending on nature of projectile involved and incident energy used in the reactions. For example along with the complete fusion, the contribution of incomplete fusion, direct reaction is also observed in these reactions and an effort is made to address them with the help of dynamical cluster decay model[DCM]. DCM provides information regarding cross sections of all compound nucleus (CN) based decay processes on equal footing and the effect of angular momentum, excitation energy, temperature, deformations and orientations can be duly incorporated wherever applicable. The study of nuclear reactions induced by heavy ions with loosely bound characteristic is also a topic of great interest. The evaporation residue channels are investigated for the low energy heavy ion reactions (6He+45Sc). In 6He+45Sc reaction, the possibility of emission of three fragments (5He, 4He+1n, ER+5He) is analyzed and the behavior of all three fragmentation processes is compared. The behavior of both these is investigated above the Coulomb barrier at highest centre of mass energy. For the reaction (6He+45Sc), the process of complete fusion is taken into account while for the reaction 2H+45Sc three processes- complete fusion, incomplete fusion (1n+45Sc) and direct reaction (P0=1) is undertaken and their comparative analysis is carried out which imparts useful information regarding the dynamics of loosely bound reactions.SPMS, Thapar University, Patial
Nuclear reaction and structure effects near and beyond the β-stability line
No full textPHD, SPMSIn the present thesis an attempt has been made to investigate the structure and reaction
dynamics of some light mass nuclei from the valley of stability to drip line. The structure
behavior of these nuclei is studied by using well known microscopic Relativistic and Nonrelativistic
mean filed formalism. The densities of these formalisms are primary major input for
the reaction dynamics in Glauber model. The detail of our work is given in the following
chapters. The thesis consists of seven chapters. A brief outline of the chapters is as follow:
Chapter 1
Chapter I of the thesis is introductory in nature which includes a brief survey of the nuclear
phenomenon which occurs in these days. A summary of recent methods and work of succeeding
chapters is also given.
Chapter 2
Chapter II consists the brief descriptions of the formalisms which include mean field formalisms.
The non-Relativistic mean field and relativistic mean field formalisms are used to investigate the
structural properties. The Glauber model is also described for the reaction dynamics in this
chapter.
Chapter 3
In this chapter, we have investigated the bulk properties of nuclear systems. The Ground state
properties like binding energy, root mean square charge radius, quadrupole deformation and
nucleonic density distributions etc. are described after obtained from the relativistic and nonrelativistic
mean field formalisms. The estimated values of bulk properties are also compared
with the available experimental data.
Chapter 4
Chapter IV, we have studied the density distributions of some light mass nuclei in the frame-work
of the non-relativistic Hartree-Fock and the relativistic mean field formalisms in light mass
region. The structure and bubble effect for 22O, 23F, 34Si, 36S,36Ar and 46Ar nuclei is studied. Such
effect is of huge relevance in the drip-line and the superheavy region.
Chapter 5
In this chapter, we have discussed the reaction cross sections of light mass nuclei using Glauber
model with densities from relativistic and non-relativistic mean field formalism. A list of various
inputs of the Glauber model is also given in this chapter. The mean field densities of projectile
and target nuclei are converted in the form of Gaussian coefficients and listed in the chapter in
terms of 2 Gaussian and 4 Gaussian coefficients. The sensitivity of converted densities has been
checked with the RMF and HF densities in terms of their density profiles. An effort is made to
address the structure effects in the context of dynamical evolution of the nuclear systems. A
comparative study of the reaction cross sections using densities from RMF and non-RMF
formalism
Chapter 6
Chapter VI contains the discussion of structural properties and reaction dynamics of halo
nuclear systems. The results are also compared with the experimental data which are available.
We also try to extend our formalisms for the investigation of recently observed 31Ne and 37Mg
halo nuclear systems.
Chapter 7
Conclusion based on the present study is finally drawn in the concluding chapter VII. The
significance of the present work and scope of future research work is also discussed in this
concluding chapter
Investigation of Fusion Hindrance in the Decay of Pre-actinide 204Po84 Nuclear System
No full textM.Sc. (Physics)In view of present day developments in the domain of theoretical nuclear physics, it is extremely important & essential to study the nuclear dynamics and related aspects at the extreme conditions of temperature, angular momentum, & energies in reference to recent advances in the field of experimental nuclear physics. One of the important aspects in this category is the fusion hindrance. Fusion hindrance in pre-actinide region is currently an active area of investigation as majority of nuclei in this mass region respond to this kind of mechanism. We have investigated the fusion hindrance in the decay of 204Po formed in 16O+188Os reaction using the Dynamical Cluster decay Model (DCM). We have calculated the evaporation residue and Fission cross section in reference to available experimental data. As expected investigated nuclear reaction does not lead to fusion hindrance at the selected range of incident energies.SPM
Role of Deformations in Cluster Radioactivity using Modified Preformed Cluster Model
No full textThe cluster decay of deformed parents is studied using the Preformed Cluster
Decay Model (PCM) having deformation and orientation effects included in it. The
main strength of the model is that it treats the binary fragmentation on equal
footing along with very important information regarding structural features of
fragmentation process. This facility is not available in other fission and statistical
models. The role of deformations and orientations seems to be extremely essential
besides shell structure and Q-value consideration in this rare decay process, giving
fragments in between α-particles and fission fragments. It is of great interest to see
that in what way the inclusion of deformations and orientations effects of the
decaying fragments influence the potential energy surface PES behavior. Because
of the apparent variation in the PES of the fragmentation process, the preformation
probability P0 and tunneling penetrability gets modified which influences the decay
constant and half life times of clusters accordingly. It may be noted that the
scattering potential barrier (position as well as height) gets modified with
deformation and orientation effects of outgoing fragments thereby effecting
tunneling path and hence the penetrability P.
The work carried out in this thesis seems highly relevant in context of present day
developments in low energy nuclear structure physics and could provide handful
information for the future experiments in the related area
α- Particle Induced Fusion-Fission Dynamics at E= 140 MeV
No full textM.Sc. (Physics)Alpha particle induced fusion fission dynamics has been studied in present work for four targets i.e. nat Ag, 165Ho, 139 La and 197Au. The dynamical cluster-decay model (DCM) has been used for present set of calculations. The DCM based cross-section find reasonable comparison with experimental data for nat Ag, 139La, 165Ho and 197Au. In case of 139La, fragments in the fission range are largely suppressed and a cluster type emission is observed. All the calculations are done at incident energy E=140 MeV so the results carry some useful information regarding α-induced fission of nuclei under considerations.
The present work consists of three chapters. The first chapter is introductory in nature. The second chapter consists of dynamical cluster-decay model developed to study the decay of compound nuclei (CN) formed in low-energy reactions. The Dynamical Cluster Decay Model (DCM) is a vibrant model which includes the deformation effects of nuclear systems and the preformation probability (one of the important parameter of DCM) imparts much needed nuclear structure information. The results are summarized in chapter3SPM
Role of Proximity Interaction in Fusion-Fission and Related Phenomena
No full textM.Sc. (Physics)Proximity interactions have been studied for three channel i.e. 64Ni+112,118,124Sn176,182,188PtA1+A2. The role of Proximity potential has been studied for above mentioned nuclear reactions using semi classical Extended Thomas Fermi (ETF) approach in SEDF under frozen approximation. Dynamical Cluster Decay (DCM) model is used to investigate the decay pattern whereas ℓ-summed Wong formula has been used for the estimation of fusion excitation functions.
The present work consists of three chapters.
Chapter 1: Introductionary part of all proximity potentials, its different versions and related historical background in reference to fusion-fission dynamics.
Chapter 2: Contains Dynamical cluster Decay Model (DCM), which has been extensively used during last one decade to understand the decay mechanism of nuclear systems formed in heavy ion reactions. In this work we have exploited the advantage of using different Skyrme forces, giving different barriers within one reaction. The dynamical cluster Decay Model (DCM) is a vibrant model which includes the deformation effects of nuclear system and the preformation probability impart much needed nuclear structure information. Wong formula is also discussed in brief.
Chapter 3: Consist of calculations and results. We observe that, the DCM based cross-sections (using GSkI force in proximity interaction) find good comparison with experimental data except at one highest energy, indicating a possibility of competing quasi-fission process at this highest energy. The ℓ-summed Wong formula, with effects of deformation and orientation of nuclei included, fits the fusion cross-sections data exactly for GSkI force, requiring additional barrier modification for SIII Skyrme force
Halo structure of neutron drip line nuclei and related aspects
No full textM.Sc., SPMSThe ground state decay of a large number of neutron rich (n-rich) light nuclei near the neutron dripline is studied using the Cluster Core Model (CCM). The CCM model find its basis in the well known Quantum mechanical Fragmentation Theory (QMFT), which have been applied successfully to study the decay of nuclear systems in light, intermediate, heavy and superheavy mass region. The halo nature of possible neutron drip line nuclei is studied via the minima in potential energy surfaces (PES), which in turn correspond to the most probable configuration. In present work, the main emphasis is on the angular momentum and deformation & orientation effects on halo nuclei. It is of great interest to see that in what way the angular momentum and deformations and orientations effects of the decaying fragments influence the potential energy surface PES behaviour of these rare light nuclei. The role of angular momentum and deformations & orientations seem to affect the fragmentation path of halo nuclei near the dripline. In other words, the cluster+core configuration seem to influence with inclusion of angular momentum and deformation effects in some of the cases studied in present work. Such studies are of extreme importance as the halo nuclei are used in break up reactions besides being used as the radioactive ion beams as a projectile because these nuclei are very loosely bound, unstable and have short half-life periods. The work carried out in this work seems highly relevant in context of present day developments in nuclear physics at low energies and could provide handful information for the further research work in the area of these lighter neutron rich nuclei near the dripline.
The introduction of neutron drip line halo nuclei is given in chapter 1. The methodology used (CCM) in the present work is given in chapter 2 and the results are discussed in chapter 3
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