Cross-sections for formation of 89Zr m through 90Zr( [formula omitted]) 89Zr m reaction over neutron energy range 13.73 MeV to 14.77 MeV

Abstract

The cross-sections for formation of metastable state of 89Zr ( 89Zr m , 0.588 MeV, 4.16 m) through 90Zr( n , 2 n ) 89Zr m reaction induced by 13.73 MeV to 14.77 MeV neutrons were measured for the first time and also theoretically estimated using Empire-II and Talys programs. At 13.73 MeV neutron energy, the 89Zr nuclei can be excited to metastable state, 89Zr m , when the first and the second emitted neutrons have energies lower than the most probable energy ∼ 0.64 MeV . The probability of exciting 89Zr nuclei to energy levels higher than 0.588 MeV and therefore of populating the metastable state through decay process increases with increasing neutron energy. The measured cross-sections vary from 41 ± 3 mb to 221 ± 15 mb over neutron energies 13.73 MeV to 14.77 MeV, and are in agreement with the cross-sections estimated using Empire-II code. The formation of 89Zr m is favoured when the first and the second reaction neutrons are emitted with the most probable energies rather than lower energy, except for 13.73 MeV neutrons.