BirBikram Singh - Academia.edu (original) (raw)
Papers by BirBikram Singh
Physical Review C, May 28, 2008
The clustering effects in light mass alpha conjugate 20 Ne, 28 Si and non-alpha conjugate 21 Ne, ... more The clustering effects in light mass alpha conjugate 20 Ne, 28 Si and non-alpha conjugate 21 Ne, 22 Ne nuclear systems have been investigated comparatively, within the collective clusterization approach of dynamical cluster-decay model. The evolution of cluster structure with temperature at three different temperatures corresponding to ground state, Ikeda's threshold energy and experimentally available energy has been made by taking into account the modified pairing strength in liquid drop energies. The results present that in addition to xα-type clusters (x is an integer) and xn-xα type clusters in alpha conjugate and non-alpha conjugate nuclear systems, respectively, np-xα type (n-neutron, p-proton) clusters are also preformed significantly at higher experimental excitation energy due to decreased pairing strength in liquid drop energies with rising temperature. Further, the fragmentation analysis has been undertaken at higher excitation energies to explore the reaction mechanism in the decay of different Z = 5, 6, 7 (or complementary Z = 3, 4, 5) fragments/clusters in reference to experimentally available Z-distribution data. The analysis depicts the presence of competing mechanisms of fusion-fission (FF) and deep inelastic orbiting (DIO) in the decay path, where the contribution of DIO cross-section σ DIO has been evaluated empirically. The higher contribution of σ DIO has been found for C-yield in all three 20 Ne * , 21 Ne * and 22 Ne * nuclear systems and the experimental verification is called for the same. The DCM calculated total cross-sections for different Z-fragments are in agreement with the experimental data.
Journal of Nuclear Physics, Material Sciences, Radiation and Applications, Aug 31, 2021
The purpose of the present work is to investigate the alpha (α) emission as competing mode of one... more The purpose of the present work is to investigate the alpha (α) emission as competing mode of one proton emission using the preformed cluster decay model (PCM). PCM is based on the quantummechanical tunneling mechanism of penetration of the preformed fragments through a potential barrier, calculated within WKB approximation. To explore the competing aspects of α and one proton radioactivity, we have chosen emitters present immediately above and below the Z = 82 shell closure i.e. 177 Tl and 185 Bi by taking into account the effects of deformations (β 2) and orientations of outgoing nuclei. The minimized values of fragmentation potential and maximized values of preformation probability (P 0) for proton and alpha fragment demonstrated the crucial role played by even Z-even N daughter and shell closure effect of Z = 82 daughter, in 177 Tl and 185 Bi, respectively. The higher values of P 0 of the one proton further reveal significance of nuclear structure in the proton radioactivity. From the comparison of proton and α decay, we see that the former is heavily dominating with larger values of P 0 in comparison to the later. Theoretically calculated half-lives of one proton and α emission for spherical and deformed considerations have also been compared with available experimental data.
Physical Review C, May 17, 2021
The investigation of fusion reactions involving light neutron-rich exotic nuclei is of paramount ... more The investigation of fusion reactions involving light neutron-rich exotic nuclei is of paramount significance to understand nucleosynthesis in astrophysical scenarios. It is also estimated as a possible heat source to ignite 12 C + 12 C reaction and production of x-ray superbursts from accreting neutron star. Recently, the fusion of neutron-rich 20 O with 12 C target has been studied with measurement of fusion cross-section (σ fus). Bass model under predicts the σ fus and time-dependent Hartree-Fock model also fails to explain the experimental data. To explicate the same, the investigation of 20 O + 12 C reaction at near barrier energies has been made within quantum mechanical fragmentation-based dynamical cluster-decay model (DCM). Within DCM, the fragmentation potential comprises temperature-dependent Coulomb, nuclear and centrifugal potentials, along with temperature-dependent binding energies (T.B.E.) calculated within the macroscopic approach of Davidson mass formula. Recently, we have explored the temperature-dependence of different nuclear properties and nuclear symmetry energy within microscopic relativistic mean-field (RMF) theory [M. Kaur et al., Nucl. Phys. A 1000, 121871 (2020)]. In the present work, we inculcate the microscopic T.B.E. from RMF theory within DCM and investigate the structure of fragmentation potential for 32 Si * formed in 20 O + 12 C reaction, comparatively for macroscopic (mac) and microscopic (mic) T.B.E. obtained from Davidson mass formula and RMF theory, respectively. The structure and magnitude of fragmentation potential are found to change drastically/notably along with a change in energetically favored/minimized fragments for both choices of T.B.E. The α particles (4 He, 5 He) are favored at lower angular momenta in fragmentation profile for mic T.B.E. case only, which is in the agreement with predictions of statistical model results. This change in the nuclear structure embodied via fragmentation potential energy carries its imprints in the preformation probability P 0 of different fragments and affects the contribution of individual light-charged particle (LCP) channel in the σ fus. A comparison of the relative cross-section of different LCP channels toward σ fus is quite different for both cases of T.B.E. The cross-section of 2 H and 4 He LCP channels is relatively enhanced for mic T.B.E. compared to mac T.B.E. Among different LCP channels, the 5 He channel is the major contributor in σ fus , which is in line with the results of the statistical EVAPOR model. The DCM-calculated σ fus is in agreement with the experimental data.
Nucleation and Atmospheric Aerosols, 2018
Physical Review C, Jan 24, 2023
Nucleation and Atmospheric Aerosols, 2020
Journal of Physics G, May 15, 2012
AIP Conference Proceedings, 2018
Nuclear Structure Physics, 2020
AIP Conference Proceedings, 2018
ADVANCED MATERIALS AND RADIATION PHYSICS (AMRP-2020): 5th National e-Conference on Advanced Materials and Radiation Physics, 2021
The purpose of this work is to study the dynamics of competing α and 208Pb daughter cluster radio... more The purpose of this work is to study the dynamics of competing α and 208Pb daughter cluster radioactive decays using the preformed cluster decay model (PCM), within the collective clusterization approach of Quantum Mechanical Fragmentation Theory (QMFT). The QMFT based fragmentation potential comprises of binding energy (B.E) (which is the sum of liquid drop energy (VLDM), based on semi empirical mass formula of Seeger and shell corrections (δU) given by Myers and Swiatecki), Coulomb potential (VC) and nuclear proximity potential (VP) of the cluster and daughter nuclei in the ground state decay of the radioactive parent nuclei. To explore the competing aspects of α and 208Pb daughter cluster radioactivities, we have chosen 222Ra, 226Th, 228Th, 231Pa, 230U and 232U parent nuclei. The crucial role played by shell closure effects is demonstrated in minimized values of fragmentation potential for cluster accompanied by doubly-magic 208Pb daughter nucleus in comparison to neighboring fragments. The higher values of preformation probabilities, P0 of these clusters further reveal significance of nuclear structure in the cluster radioactivity process. We have calculated the half-lives via fragmentation potential, preformation probability, scattering potential for spherical case, of chosen nuclei, and then compared with the given experimental data. From the comparison of α cluster and 208Pb daughter decays, we see that the former is heavily dominating with larger values of P0 in comparison to the later as evident from the experimentally observed high count rate of α cluster in such decays. However, the penetrability for both types of decays is almost similar. The experimental data and PCM calculated results are in fair comparison for all the chosen cases.
3RD INTERNATIONAL CONFERENCE ON CONDENSED MATTER AND APPLIED PHYSICS (ICC-2019), 2020
AIP Conference Proceedings, 2020
Nuclear Physics A, 2018
The quantum mechanical fragmentation theory (QMFT)-based dynamical cluster-decay model (DCM) has ... more The quantum mechanical fragmentation theory (QMFT)-based dynamical cluster-decay model (DCM) has been applied to predict the fusion cross section (σ f us) for the compound systems (CS) 60 Zn * , 60 Ni * and 60 Fe * formed, respectively, via 4 He+ 56 Ni, 4 He+ 56 Fe and 4 He+ 56 Cr, reactions, by fixing the only parameter (neck length R emp) of the model, empirically with the available experimental data on σ f us of 44,48 Ti * and 68 Ge * formed through 4 He induced reactions at different incident energies, i.e., E lab ∼ 10, 13, 17 MeV. We have investigated the effect of neutron to proton (N/Z) ratio in the decay of CS under study, i.e., 60 Zn * , 60 Ni * and 60 Fe *. The contributions of light-particles cross section (σ LP s), intermediate mass fragments cross section (σ I MF s) and symmetric mass fragments cross section (σ SMF s) are taken together to calculate σ f us (= σ LP s + σ I MF s + σ SMF s). The small contribution of SMFs is seen in σ f us , the contributions of LPs and IMFs yields being much more prominent, for the decay of all CS under study at different incident energies. We see that the preformation probability (P 0) and penetrability (P) for SMFs decrease with increase in the value of N/Z ratio, and hence the symmetric breakup drops-out-of-favor for higher N/Z values. In other words, the symmetric mass decay is favored in the case of 60 Zn * having N = Z, the LPs, IMFs and SMFs yields increasing with increase in incident energy.
DESCRIPTION We have extended the study of binary symmetric decay (BSD) of extremely light mass co... more DESCRIPTION We have extended the study of binary symmetric decay (BSD) of extremely light mass compound systems 20,21,22Ne* formed in 10,11B+ 10,11B reactions at E_{lab} = 48 MeV, to explore the role of deformations and orientations, using the Dynamical Cluster decay Model (DCM). The results are compared with purely spherical consideration of nuclei to bring out the effects of oriented nuclei.
excited CN 47V* formed in nearly symmetric and asymmetric reactions 23Na+24Mg (Elab=89.1 MeV) and... more excited CN 47V* formed in nearly symmetric and asymmetric reactions 23Na+24Mg (Elab=89.1 MeV) and 35Cl+12C (Elab=200 MeV), respectively, with the same excitation energy ECN *=64.1 MeV, is studied by using the Dynamical Cluster decay Model (DCM) of Gupta and collaborators. The DCM has been applied successfully to the decay of light, medium, heavy and super-heavy mass compound nuclei. 47V*offers an ideal example for studying the entrance-channel effects, since it belongs to the well established mass region 40 ≤ ACN ≤ 80 of FF phenomenon. It is relevant to mention here that the light compound nuclei 28Al*, 48Cr* and 56Ni* decays have been studied extensively by Gupta and collaborators using the DCM, along with entrance channel effects in the decay of 48Cr* [4]. We intend to extend the application of DCM to study the decay of light odd mass CN 47V*, for the first time. Calculations are worked out in terms of neck length parameter ΔR, the only parameter of the DCM. Interestingly, our cal...
Physical Review C, May 28, 2008
The clustering effects in light mass alpha conjugate 20 Ne, 28 Si and non-alpha conjugate 21 Ne, ... more The clustering effects in light mass alpha conjugate 20 Ne, 28 Si and non-alpha conjugate 21 Ne, 22 Ne nuclear systems have been investigated comparatively, within the collective clusterization approach of dynamical cluster-decay model. The evolution of cluster structure with temperature at three different temperatures corresponding to ground state, Ikeda's threshold energy and experimentally available energy has been made by taking into account the modified pairing strength in liquid drop energies. The results present that in addition to xα-type clusters (x is an integer) and xn-xα type clusters in alpha conjugate and non-alpha conjugate nuclear systems, respectively, np-xα type (n-neutron, p-proton) clusters are also preformed significantly at higher experimental excitation energy due to decreased pairing strength in liquid drop energies with rising temperature. Further, the fragmentation analysis has been undertaken at higher excitation energies to explore the reaction mechanism in the decay of different Z = 5, 6, 7 (or complementary Z = 3, 4, 5) fragments/clusters in reference to experimentally available Z-distribution data. The analysis depicts the presence of competing mechanisms of fusion-fission (FF) and deep inelastic orbiting (DIO) in the decay path, where the contribution of DIO cross-section σ DIO has been evaluated empirically. The higher contribution of σ DIO has been found for C-yield in all three 20 Ne * , 21 Ne * and 22 Ne * nuclear systems and the experimental verification is called for the same. The DCM calculated total cross-sections for different Z-fragments are in agreement with the experimental data.
Journal of Nuclear Physics, Material Sciences, Radiation and Applications, Aug 31, 2021
The purpose of the present work is to investigate the alpha (α) emission as competing mode of one... more The purpose of the present work is to investigate the alpha (α) emission as competing mode of one proton emission using the preformed cluster decay model (PCM). PCM is based on the quantummechanical tunneling mechanism of penetration of the preformed fragments through a potential barrier, calculated within WKB approximation. To explore the competing aspects of α and one proton radioactivity, we have chosen emitters present immediately above and below the Z = 82 shell closure i.e. 177 Tl and 185 Bi by taking into account the effects of deformations (β 2) and orientations of outgoing nuclei. The minimized values of fragmentation potential and maximized values of preformation probability (P 0) for proton and alpha fragment demonstrated the crucial role played by even Z-even N daughter and shell closure effect of Z = 82 daughter, in 177 Tl and 185 Bi, respectively. The higher values of P 0 of the one proton further reveal significance of nuclear structure in the proton radioactivity. From the comparison of proton and α decay, we see that the former is heavily dominating with larger values of P 0 in comparison to the later. Theoretically calculated half-lives of one proton and α emission for spherical and deformed considerations have also been compared with available experimental data.
Physical Review C, May 17, 2021
The investigation of fusion reactions involving light neutron-rich exotic nuclei is of paramount ... more The investigation of fusion reactions involving light neutron-rich exotic nuclei is of paramount significance to understand nucleosynthesis in astrophysical scenarios. It is also estimated as a possible heat source to ignite 12 C + 12 C reaction and production of x-ray superbursts from accreting neutron star. Recently, the fusion of neutron-rich 20 O with 12 C target has been studied with measurement of fusion cross-section (σ fus). Bass model under predicts the σ fus and time-dependent Hartree-Fock model also fails to explain the experimental data. To explicate the same, the investigation of 20 O + 12 C reaction at near barrier energies has been made within quantum mechanical fragmentation-based dynamical cluster-decay model (DCM). Within DCM, the fragmentation potential comprises temperature-dependent Coulomb, nuclear and centrifugal potentials, along with temperature-dependent binding energies (T.B.E.) calculated within the macroscopic approach of Davidson mass formula. Recently, we have explored the temperature-dependence of different nuclear properties and nuclear symmetry energy within microscopic relativistic mean-field (RMF) theory [M. Kaur et al., Nucl. Phys. A 1000, 121871 (2020)]. In the present work, we inculcate the microscopic T.B.E. from RMF theory within DCM and investigate the structure of fragmentation potential for 32 Si * formed in 20 O + 12 C reaction, comparatively for macroscopic (mac) and microscopic (mic) T.B.E. obtained from Davidson mass formula and RMF theory, respectively. The structure and magnitude of fragmentation potential are found to change drastically/notably along with a change in energetically favored/minimized fragments for both choices of T.B.E. The α particles (4 He, 5 He) are favored at lower angular momenta in fragmentation profile for mic T.B.E. case only, which is in the agreement with predictions of statistical model results. This change in the nuclear structure embodied via fragmentation potential energy carries its imprints in the preformation probability P 0 of different fragments and affects the contribution of individual light-charged particle (LCP) channel in the σ fus. A comparison of the relative cross-section of different LCP channels toward σ fus is quite different for both cases of T.B.E. The cross-section of 2 H and 4 He LCP channels is relatively enhanced for mic T.B.E. compared to mac T.B.E. Among different LCP channels, the 5 He channel is the major contributor in σ fus , which is in line with the results of the statistical EVAPOR model. The DCM-calculated σ fus is in agreement with the experimental data.
Nucleation and Atmospheric Aerosols, 2018
Physical Review C, Jan 24, 2023
Nucleation and Atmospheric Aerosols, 2020
Journal of Physics G, May 15, 2012
AIP Conference Proceedings, 2018
Nuclear Structure Physics, 2020
AIP Conference Proceedings, 2018
ADVANCED MATERIALS AND RADIATION PHYSICS (AMRP-2020): 5th National e-Conference on Advanced Materials and Radiation Physics, 2021
The purpose of this work is to study the dynamics of competing α and 208Pb daughter cluster radio... more The purpose of this work is to study the dynamics of competing α and 208Pb daughter cluster radioactive decays using the preformed cluster decay model (PCM), within the collective clusterization approach of Quantum Mechanical Fragmentation Theory (QMFT). The QMFT based fragmentation potential comprises of binding energy (B.E) (which is the sum of liquid drop energy (VLDM), based on semi empirical mass formula of Seeger and shell corrections (δU) given by Myers and Swiatecki), Coulomb potential (VC) and nuclear proximity potential (VP) of the cluster and daughter nuclei in the ground state decay of the radioactive parent nuclei. To explore the competing aspects of α and 208Pb daughter cluster radioactivities, we have chosen 222Ra, 226Th, 228Th, 231Pa, 230U and 232U parent nuclei. The crucial role played by shell closure effects is demonstrated in minimized values of fragmentation potential for cluster accompanied by doubly-magic 208Pb daughter nucleus in comparison to neighboring fragments. The higher values of preformation probabilities, P0 of these clusters further reveal significance of nuclear structure in the cluster radioactivity process. We have calculated the half-lives via fragmentation potential, preformation probability, scattering potential for spherical case, of chosen nuclei, and then compared with the given experimental data. From the comparison of α cluster and 208Pb daughter decays, we see that the former is heavily dominating with larger values of P0 in comparison to the later as evident from the experimentally observed high count rate of α cluster in such decays. However, the penetrability for both types of decays is almost similar. The experimental data and PCM calculated results are in fair comparison for all the chosen cases.
3RD INTERNATIONAL CONFERENCE ON CONDENSED MATTER AND APPLIED PHYSICS (ICC-2019), 2020
AIP Conference Proceedings, 2020
Nuclear Physics A, 2018
The quantum mechanical fragmentation theory (QMFT)-based dynamical cluster-decay model (DCM) has ... more The quantum mechanical fragmentation theory (QMFT)-based dynamical cluster-decay model (DCM) has been applied to predict the fusion cross section (σ f us) for the compound systems (CS) 60 Zn * , 60 Ni * and 60 Fe * formed, respectively, via 4 He+ 56 Ni, 4 He+ 56 Fe and 4 He+ 56 Cr, reactions, by fixing the only parameter (neck length R emp) of the model, empirically with the available experimental data on σ f us of 44,48 Ti * and 68 Ge * formed through 4 He induced reactions at different incident energies, i.e., E lab ∼ 10, 13, 17 MeV. We have investigated the effect of neutron to proton (N/Z) ratio in the decay of CS under study, i.e., 60 Zn * , 60 Ni * and 60 Fe *. The contributions of light-particles cross section (σ LP s), intermediate mass fragments cross section (σ I MF s) and symmetric mass fragments cross section (σ SMF s) are taken together to calculate σ f us (= σ LP s + σ I MF s + σ SMF s). The small contribution of SMFs is seen in σ f us , the contributions of LPs and IMFs yields being much more prominent, for the decay of all CS under study at different incident energies. We see that the preformation probability (P 0) and penetrability (P) for SMFs decrease with increase in the value of N/Z ratio, and hence the symmetric breakup drops-out-of-favor for higher N/Z values. In other words, the symmetric mass decay is favored in the case of 60 Zn * having N = Z, the LPs, IMFs and SMFs yields increasing with increase in incident energy.
DESCRIPTION We have extended the study of binary symmetric decay (BSD) of extremely light mass co... more DESCRIPTION We have extended the study of binary symmetric decay (BSD) of extremely light mass compound systems 20,21,22Ne* formed in 10,11B+ 10,11B reactions at E_{lab} = 48 MeV, to explore the role of deformations and orientations, using the Dynamical Cluster decay Model (DCM). The results are compared with purely spherical consideration of nuclei to bring out the effects of oriented nuclei.
excited CN 47V* formed in nearly symmetric and asymmetric reactions 23Na+24Mg (Elab=89.1 MeV) and... more excited CN 47V* formed in nearly symmetric and asymmetric reactions 23Na+24Mg (Elab=89.1 MeV) and 35Cl+12C (Elab=200 MeV), respectively, with the same excitation energy ECN *=64.1 MeV, is studied by using the Dynamical Cluster decay Model (DCM) of Gupta and collaborators. The DCM has been applied successfully to the decay of light, medium, heavy and super-heavy mass compound nuclei. 47V*offers an ideal example for studying the entrance-channel effects, since it belongs to the well established mass region 40 ≤ ACN ≤ 80 of FF phenomenon. It is relevant to mention here that the light compound nuclei 28Al*, 48Cr* and 56Ni* decays have been studied extensively by Gupta and collaborators using the DCM, along with entrance channel effects in the decay of 48Cr* [4]. We intend to extend the application of DCM to study the decay of light odd mass CN 47V*, for the first time. Calculations are worked out in terms of neck length parameter ΔR, the only parameter of the DCM. Interestingly, our cal...