Study on Effective Average (γ, n) Cross Section for89Y,90Zr,93Nb, and133Cs and (γ, 3n) Cross Section for99Tc

Measurement of photo-neutron cross sections and isomeric yield ratios in the 89Y(γ,xn)89−x Y reactions at the bremsstrahlung end-point energies of 65, 70 and 75 MeV

The flux-weighted average cross sections of the 89Y(γ,xn; x=1–4)89−x Y reactions and the isomeric yield ratios of the 87m,gY, 86m,gY, and 85m,gY radionuclides produced in these reactions with the bremsstrahlung end-point energies of 65, 70 and 75 MeV have been determined by an activation and off-line γ-ray spectrometric technique using the 100 MeV electron linac in Pohang Accelerator Laboratory, Korea. The theoretical 89Y(γ,xn; x=1–4)89−x Y reactioncross sections for mono-energetic photonshave been calculated using the computer code TALYS 1.6. Then the flux-weighted theoretical values were obtaind to compare with the present data. The flux-weighted experimental and theoretical 89Y(γ,xn; x=1–4)89−x Y reaction cross sections increase very fast from the threshold values to a certain bremsstrahlung energy, wherethe other reaction channels open up. Thereafter it remains constant a while and then slowly decreases with the increase of cross sections for other reactions. Similarly, the isomeric yield ratios of 87m,gY,86m,gY and 85m,gY in the 89Y(γ,xn; x=2–4)89−x Y reactions from the present work and literature data show an increasing trend from their respective threshold values to a certain bremsstrahlung energy. After a certain point ofenergy, the isomeric yield ratios increase slowly with the bremsstrahlung energy. These observations indicate the role of excitation energy and its partitioning in different reaction channels.

Measurement of bremsstrahlung-induced reaction cross-section for 93Nb using electron Linac

Cross sections for (γ, n) reaction at bremsstrahlung end point energies of 10 and 12.5MeV on niobium have been measured by the activation technique. Induced activities were measured by a high-resolution γ-ray spectrometer with a high-purity germanium (HPGe) detector. Theoretically the (γ, n) cross-section of 93Nb as a function of photon energies were also calculated using TALYS 1.4 computer code. We compared the measured data with the flux weighted average values from the available literature data based on experiments with mono-energetic photons and the theoretical calculation by the model code TALYS 1.4. The experimental values are found to be in good agreement with the theoretical value from TALYS 1.4 but are slightly higher than the flux-weighted values from mono-energetic photons