The ⁹³Nb(n,ń)⁹³Nb^m reaction is frequently used for neutron fluence determination in nuclear reactors. The suitability of the niobium monitor depends very much on knowledge of the reaction cross section and the decay data of the generated isomer state ⁹³Nb^m. Results of recent developments at various institutes concerning these data are reviewed.

The reaction cross section averaged over the ²⁵²Cf fission neutron spectrum has been remeasured, resulting in a value of (145 ± 5) mb. This is compared with values measured in the NBSR ²³⁵U standard fission neutron field and with results from other experiments.