| Popis: |
In this work, the effective resonance energy, (E) over bar (r)-value for the Ir-193(n,gamma)Ir-194 reaction was measured using cadmium ratio method. A dual monitor (Au-197-Mo-98), which has convenient resonance properties, was employed for characterization of the irradiation sites. Then analytical grade iridium oxide samples diluted with CaCO3 to lower neutron self-shielding effect stacked in small cylindrical Teflon boxes were irradiated once with a 1 mm thick Cd cylindrical box placed in a thermalized neutron field of an Am-241-Be neutron source then without it. The activities produced in samples during Ir-193(n,gamma)Ir-194 reaction were measured using a p-type HPGe detector gamma-ray spectrometer with a 44.8% relative efficiency. The correction factors for thermal, epithermal neutron self-shielding (G(th), G(epi)), true coincidence summing (F-coi) and gamma-ray self-absorption (F-s) effects were determined with appropriate approaches and programs. Thus, the experimental (E) over bar (r)-value was determined to be 2.65 +/- 0.61 eV for Ir-193 target nuclide. The recent data for Q(o) and F-Cd values for (E) over bar (r) determination were based on k(o)-NAA online database. The present experimental (E) over bar (r) value was calculated and compared with more recent values for Q(o) and F-cd for Ir-193. Additionally, the (E) over bar (r)-values was theoretically calculated from the up-to-date resonance data obtained from ENDF/B VII library using two different approaches. Since there is no experimentally determined (E) over bar (r)-value for the Ir-193 isotope, the results are compared with the calculated ones given in the literature. (C) 2016 Elsevier B.V. All rights reserved. |
