Study on effective average (γ, n) Cross Section for ⁸⁹Y, ⁹⁰Zr, ⁹³Nb, and ¹³³Cs and (γ, 3n) cross section for ⁹⁹Tc

A nondestructive detection technique was proposed for the easy assessment of long-lived radionuclides by the use of bremsstrahlung photons. The nuclide of ⁹⁹Tc was considered for the assessment over an effective average ⁹⁹Tc (γ, 3n) ⁹⁶Tc cross section. For validating the experimental method on ⁹⁹Tc, photonuclear (γ, n) cross sections of ⁸⁹Y, ⁹⁰Zr, ⁹³Nb, and ¹³³Cs were measured. Continuous-energy bremsstralung photons were generated from a platinum target bombarded by an electron beam of 32/ 36MeV from an electron linac. The photonuclear (γ, n) cross sections were previously measured by Saclay (France) and Livermore (USA) laboratories for ⁸⁹Y, ⁹⁰Zr, ⁹³Nb, and ¹³³Cs nuclides. For ⁸⁹Y, ⁹⁰Zr, and ¹³³Cs, the present results were in good agreement, within 9% deviation with Saclay and an acceptable deviation of 14-36% from Livermore. In the case of ⁹³Nb, the contribution for ⁹³Nb (γ, n) 92Nb* in the metastable state was 55.2% of the total (γ, n) cross section of Saclay in an averaged form. The present experimental method was thus confirmed to show a good accuracy. The effective average cross section of ⁹⁹Tc (γ, 3n) ⁹⁶Tc was obtained as 2.30 mb in the energy range of 25.723-36 MeV.