Photoexcitation of ^93mNb in the 5- to 30-MeV Gamma-Energy Range

The cross section of the ⁹³Nb(γ, γ′)^93mNb reaction is calculated in the 5- to 30-MeV gamma-energy region in the framework of a gamma-ray cascade model with open nucleon emission channels and including pre-equilibrium contribution. The resulting cross-section curve shows one pronounced peak at the neutron separation energy with an integral of 3.1 mb-MeV up to 12 MeV. Taking into consideration the pre-equilibrium gamma emission, a negligible contribution to the calculated excitation curve results at ∼18 MeV. The influence of gamma background on the response of ⁹³Nb as a neutron fluence monitor is estimated for two practical cases.