Study of Excitation Functions of (p, n) Reactions for 56Fe and 57Fe Target from Threshold to 30 MeV

Damewan Suchiang1 and B. M. Jyrwa 2

1 Department of Physics, Tura Government College, Tura 794001, Meghalaya, India
2 Department of Physics, North Eastern Hill University, Shillong 793022, Meghalaya, India
*Email : bjyrwa@gmail.com

The Author(s) 2015. This article is published with open access at www.chitkara.edu.in/publications

Abstract: The theoretical calculation of the cross section for formation of 56,57Co in (p, n) reaction from 56,57Fe target have been study from reaction threshold to 30 MeV using TALYS-1.4 nuclear model reaction code whereby we have studied major nuclear reaction mechanisms, including direct, pre-equilibrium and compound nuclear reactions. These calculations were carried out by adjusting the effective imaginary potential, level density and shell damping parameters. It is observed that an excellent agreement between the theoretical calculated and experimental data is obtained with minimal effort on parameter fitting. We have also observed that there is significant contribution of pre-equilibrium emission in (p, n) reaction cross-section of 56Fe and 57Fe. The systematic increase in (p, n) cross-sections with increasing neutron number in reactions induced by protons on 56Fe and 57Fe is explained in terms of compound and pre-equilibrium mode.

Keywords: Iron target; Level density; shell correction; pairing interaction; Excitation function; Pre-equilibrium.

Nuclei Near and Far From β-Stability Line

R.L. Nayak, T. Sahoo and A. Acharya*
Department of physics, VSS University of Technology, Burla, Orissa, India
*Email: aacharya@iopb.res.in

This article is published with open access at www.chitkara.edu.in/publications

Abstract: Proton to neutron ratio around β-stability line presents an open challenge to the nuclear physicists. The prominent milestone in this regard is the discovery of the super heavy elements, nuclear halos in the lightest neutron-rich nuclei, experimental mapping of the nuclear shell structure near and far from stability. In this present paper, the behavior of the p- and n- halo nuclei near the β-stability line are discussed considering the variation of radius with respect to the mass number and N~Z for different nuclei. Our aim is to study the nuclear properties through neutron and proton skin. The isospin symmetry breaking is for heavy halo nuclei of strong interest.
Keywords: Neutron and proton drip line nuclei; β stability line; n- and p- skin

Level Statistics of SU(3)↔SU(3)Transitional Region

Level statistics oftransitional region of SU(3)↔SU(3) interacting boson model is described with emphasis on the nearest neighbor spacing distributions. The energy levels of transitional Hamiltonian are calculated via the SO(6) representation of eigenstates. By employing the MLE technique, the parameter of Abul-Magd distribution is estimated which suggests less regular dynamics for transitional region as compared to dynamical symmetry limits. Also, the O(6) dynamical symmetry which is known as the critical point of this transitional region, describes a deviation to more regular dynamics. 

Keywords:- Shape Phase Transition; Interacting Boson Model (IBM); Spectral Statistics; Maximum Likelihood Estimation (MLE). 

Authors:- H. Sabri P. Hossein Nezhade Gavifekr, Z. Ranjbar, N. Fouladi1 

Department of Nuclear Physics, University of Tabriz, Tabriz-51664, Iran.
Email:- h-sabri@tabrizu.ac.ir

M. A. Jafarizadeh 

Department of Theoretical Physics and Astrophysics, University of Tabriz, Tabriz-51664, Iran.
Research Institute for Fundamental Sciences, Tabriz-51664, Iran.

http://jnp.chitkara.edu.in//pdf/papers/05_JNPMSRA_Sabri.pdf

Fission in Rapidly Rotating Nuclei

We study the effect of rotation in fission of the atomic nucleus ²⁵⁶Fm using an independent-particle shell model with the mean field represented by a deformed Woods-Saxon potential and the shapes defined through the Cassinian oval parametrization. The variations of barrier height with increasing angular momentum, appearance of double hump in fission path are analysed. Our calculations explain the appearance of double hump in fission path of 256Fm nucleus. The second minimum vanishes with increase in angular momentum which hints that the fission barrier disappears at large spin. 

Keywords:- Fission, Cassinian ovals, Rotating nuclei 

Authors:- A. K. Rhine Kumar and Vinay Suram 

Department of Physics, Indian Institute of Technology Roorkee-247667, Uttarakhand, India

http://jnp.chitkara.edu.in//pdf/papers/04_JNPMSRA_Rhine.pdf

On the Fusion of Neutron/ Proton-Rich Colliding Nuclei Using Isospin-Dependent Potentials

By using different isospin dependent proximity-type potentials, we performed a detailed study of neutron/proton-rich colliding nuclei with N/Z ratio between 0.5 and 2.0. Isotopes of three different series namely, Ne-Ne, Ca-Ca, and Zr-Zr are taken into account. A monotonous increase (decrease) in the fusion barrier positions (heights) using a unified second order nonlinear parametrization in the normalized fusion barrier positions and heights with N( Z −1) is presented. These predictions are in good agreement with the available theoretical as well as experimental results. The fusion probabilities, however shows linear dependence. Further, the neutron/proton content plays dominant role at near barrier energies only. Our results are also independent of the model used as well as reaction partner and isospin content. More experiments are needed to verify our predictions. 

Keywords: Heavy-ion fusion reaction, proximity potential, fusion barriers and cross sections. 
Authors:- Ishwar Dutt

School of Applied Sciences, Chitkara University, Himachal Pradesh-174 103, India.
Department of Physics, Panjab University, Chandigarh-160014, India.
Email:- ishwar.dutt1@chitkarauniversity.edu.in

Maninder Kaur
Department of Physics, Panjab University, Chandigarh-160014, India.