Chapter 16
Systematic Study of Po Compound
Nuclei Using Evaporation Residue,
Fission Cross-Section, and Neutron
Multiplicity as a Probe
Ruchi Mahajan
Abstract Statistical model calculations for neutron multiplicity, evaporation residue,
and fission cross-section have been performed for
18 O +
192 Os populating
210 Po compound nucleus in the excitation energy range 52.43–83.51 MeV. Experimental fusion
cross-section has been fitted using CCFULL code. Evaporation residue and fission
cross-section are then fitted using Bohr–Wheeler’s formalism including shell effects
in the level density and fission barrier by using scaling factor in the range 1.0–0.75.
The results of the calculations are in good agreement with the experimental data. In
this chapter, we are presenting the results of these calculations.
16.1 Introduction
The understanding of the fission dynamics of a nucleus, particularly in the mass
region ≈200, continues to be challenging task for the nuclear physicists [1]. In order
to have a better insight of the fission dynamics in this mass region, many statistical as well as dynamical approaches have been used. The key ingredients of these
approaches include the spin distribution of the compound nucleus (CN), nuclear level
density parameters, shell effects in fission barrier, and the potential energy surface. In
general, the fission barrier used in these models has a macroscopic (liquid drop) part
and a microscopic (shell correction) part. The nuclear level density parameter is also
sensitive to the shell correction and deformation. Even though significant progress
has been made in the understanding of the fission process, there are ambiguities
in choosing the parameters of the theoretical models [2–5]. At low energies, CN
decays predominantly by emission of particles and fission. Experimental observations clearly show that fusion cross-section is significantly reduced in medium mass
region even for very asymmetric systems due to onset of non-compound nuclear
processes like quasi fission (QF) [6, 7]. Evaporation residues (ERs) are the pure
signatures of CN formation and can become a useful probe to study the statistical as
well as dynamical aspects of the fusion–fission reactions.
R. Mahajan (B)
Department of Physics, Panjab University, Chandigarh 160014, India
e-mail: ruchimahajan4@gmail.com
© Springer Nature Singapore Pte Ltd. 2021
R. K. Puri et al. (eds.), Advances in Nuclear Physics, Springer Proceedings
in Physics 257, https://doi.org/10.1007/978-981-15-9062-7_16
219
Systematic Study of Po Compound
Nuclei Using Evaporation Residue,
Fission Cross-Section, and Neutron
Multiplicity as a Probe
Ruchi Mahajan
Abstract Statistical model calculations for neutron multiplicity, evaporation residue,
and fission cross-section have been performed for
18 O +
192 Os populating
210 Po compound nucleus in the excitation energy range 52.43–83.51 MeV. Experimental fusion
cross-section has been fitted using CCFULL code. Evaporation residue and fission
cross-section are then fitted using Bohr–Wheeler’s formalism including shell effects
in the level density and fission barrier by using scaling factor in the range 1.0–0.75.
The results of the calculations are in good agreement with the experimental data. In
this chapter, we are presenting the results of these calculations.
16.1 Introduction
The understanding of the fission dynamics of a nucleus, particularly in the mass
region ≈200, continues to be challenging task for the nuclear physicists [1]. In order
to have a better insight of the fission dynamics in this mass region, many statistical as well as dynamical approaches have been used. The key ingredients of these
approaches include the spin distribution of the compound nucleus (CN), nuclear level
density parameters, shell effects in fission barrier, and the potential energy surface. In
general, the fission barrier used in these models has a macroscopic (liquid drop) part
and a microscopic (shell correction) part. The nuclear level density parameter is also
sensitive to the shell correction and deformation. Even though significant progress
has been made in the understanding of the fission process, there are ambiguities
in choosing the parameters of the theoretical models [2–5]. At low energies, CN
decays predominantly by emission of particles and fission. Experimental observations clearly show that fusion cross-section is significantly reduced in medium mass
region even for very asymmetric systems due to onset of non-compound nuclear
processes like quasi fission (QF) [6, 7]. Evaporation residues (ERs) are the pure
signatures of CN formation and can become a useful probe to study the statistical as
well as dynamical aspects of the fusion–fission reactions.
R. Mahajan (B)
Department of Physics, Panjab University, Chandigarh 160014, India
e-mail: ruchimahajan4@gmail.com
© Springer Nature Singapore Pte Ltd. 2021
R. K. Puri et al. (eds.), Advances in Nuclear Physics, Springer Proceedings
in Physics 257, https://doi.org/10.1007/978-981-15-9062-7_16
219