Measurement of effective neutron cross section of the reaction 98Mo (n, γ) 99Mo in TRR nuclear reactor by using thermal neutrons

The effective cross section of 98Mo was measured using Westcott's convention. Diluted samples of natural MoO3 were irradiated for 15 min in the channel D6 of the core of the Tehran research reactor (TRR). The neutron flux at irradiation position was measured using diluted Au2O3 and Co3O4. The effective cross section was deduced as 0.526 ± 0.02b obtained from thermal flux. Index in Westcott's convention, rT/T0 at the irradiation position was obtained as 0.0545 ± 0.001. The contribution of the epithermal neutrons in total neutron activity of 99Mo was 69%. The necessary correction factors such as thermal neutron self- shielding (Gth) and epithermal neutron self-shielding (Gepi), and gamma-ray attenuation (Fg) were taken into account. The results were presented and compared with effective cross section in evaluated nuclear data laboratory such as JENDL-4, KAERI and evaluated data by Mughabghab.