Effects of the Changes in the Neutron Number of Isotonic Nuclei on the Tow-Component Partial Level Density Formula Corrected for Pairing in Pre-Equilibrium Reactions

Abstract

Ericson’s formula describes the partial level density (PLD) of pre-equilibrium reactions. PLD with pairing correction can be calculated by modifying Ericson’s formula using four methods, namely, pairing, improved pairing, exact Pauli and back shift energy corrections. The variations in the PLD values of each of the four formulas of strontium (88Sr), Yttrium (89Y) and Zirconium (90Zr) isotones have been calculated. Results showed that the PLD values that uses pairing and improved pairing corrections do not vary for different isotones. However, a small change in PLD values was observed when exact Pauli correction and back shift energycorrection were utilised. The change in the PLD values using back shift energy correction was bigger than the values obtained using exact Pauli correction. Therefore, the use of back shift formula is recommended in nuclear cross-section calculations because it results in noticeable changes with any small increase in mass number.