Effect of N/Z in pre-scission neutron multiplicity for ^16,18O+^194,198Pt systems

¹ Department of Physics, Panjab University, Chandigarh 160014, India
² Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India
³ Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata 700064, India
⁴ Department of Physics and Astrophysics, University of Delhi 110007, India
⁵ Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
⁶ Department of Physics, Calicut University, Calicut 673635, India

^a Present Address : S. V. Government College Ghumarwin, Bilaspur 174021 (H.P.), India
^b Corresponding Author : bivash@pu.ac.in

Published online: 20 March 2014

Abstract

This paper report the summary of the experimental results of pre-scission neutron multiplicities from four compound nuclei, namely ^{210,212,214,216}Rn, and statistical model analysis of the corresponding data. The compound nuclei ^{210,212,214,216}Rn having N/Z values as 1.441, 1.465, 1.488, 1.511 respectively are populated through the ^16,18O+^194,198Pt reactions at excitation energies of 50, 61, 71.7 and 79 MeV. The measured neutron multiplicities are further analyzed with the statistical model of nuclear decay where fission hindrance due to nuclear dissipation is considered. The N/Z dependence of the dissipation strength at lowest excitation energy of the compound nuclei suggests shell closure effects. However, such effects are not observed at higher excitations where the variation of the dissipation strength with N/Z does not show any specific trend. The variation of N/Z in fission time scale is also shown.