Eur. Phys. J. A (2021) 57: 48
https://doi.org/10.1140/epja/s10050-021-00373-3

Regular Article – Experimental Physics

Nuclear level density and thermal properties of ${}^{115}\text{Sn}$ from neutron evaporation

¹ Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, 700 064, Kolkata, India
² Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, 400 094, Mumbai, India
³ Institute of Fundamental and Applied Sciences, Duy Tan University, 700000, Ho Chi Minh City, Vietnam
⁴ Faculty of Natural Sciences, Duy Tan University, 550000, Danang, Vietnam

^a roypratap@vecc.gov.in, pratapproy@gmail.com

Received: 24 November 2020
Accepted: 27 January 2021
Published online: 5 February 2021

Abstract

The nuclear level density of ${}^{115}\text{Sn}$ has been measured in an excitation energy range of $\sim 2$–9 MeV using the experimental neutron evaporation spectra from the ${}^{115}\text{In}$(p, n)${}^{115}\text{Sn}$ reaction. The experimental level densities were compared with the microscopic Hartree–Fock BCS (HFBCS), Hartree–Fock–Bogoliubov plus combinatorial (HFB + C), and an exact pairing plus independent particle model (EP + IPM) calculations. It is observed that the EP + IPM provides the best description of the experimental data among the three. The thermal properties (entropy and temperature) of ${}^{115}\text{Sn}$ have been investigated from the measured level densities. The experimental temperature profile as well as the calculated heat capacity show distinct signatures of a transition from the strongly-paired nucleonic phase to the weakly paired one in this nucleus.