Determination of effective resonance energies for the (n,gamma) reactions of Sm-152 and Ho-165 by using dual monitors


Budak M. G. , Karadag M., Yucel H.

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, cilt.268, ss.2578-2584, 2010 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 268
  • Basım Tarihi: 2010
  • Doi Numarası: 10.1016/j.nimb.2010.06.037
  • Dergi Adı: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
  • Sayfa Sayıları: ss.2578-2584

Özet

The effective resonance energies (E) over barr for the (n,gamma) reactions of Sm-152 and Ho-165 isotopes were determined by using dual monitors (Mn-55-Mo-98) due to their favourable resonance properties The samples were irradiated in an isotropic neutron field obtained from Am-241-Be neutron sources The induced activities were measured with a high efficient, p-type Ge detector. The necessary correction factors for thermal neutron self-shielding (Go,), resonance neutron self-shielding (Ge,), self absorption (F,) and true coincidence summing (F-cor,,) effects for the measured gamma-rays were taken into account Thus, the experimental Er values for above (n,y) reactions are found to be 8.65 1 80 eV for 152Sm and 12 90 269 eV for '65Ho isotopes, respectively The Er-values for both Sm-152 and Ho-165 isotopes were also theoretically calculated from the newest resonance data in the literature. Theoretically calculated Er-values are estimated to be 8.34 eV and 8.53 eV for '525m by two different approaches, which are generally. much smaller than that the present experimental value by 1.4-3.6% for Sm-152 In case of Ho-165 isotope, the theoretically calculated Er-value of 8.63 eV from the first approach deviates substantially from the measured value by about 33%, whereas the theoretical Er-value of 12 95 eV from the second approach agrees very well with our experimentally determined Er-value The results show that the present experimental Er-values for Sm-152 and Ho-165 isotopes agree with the calculated ones from the second approach within limits of the estimated uncertainty if the recently evaluated resonance data are used However, it is worth noting that the results for Er-value calculated from the first approach are not satisfactorily accurate because of neglecting the neutron widths in that approach Therefore, this study implies that it be regarded to the experimentally determined Er-value introduced in k0-NAA method for the determination of any analytical result rather than its theoretical value (C) 2010 Elsevier B V All rights reserved