THE PRODUCTION OF THE RADIOISOTOPES ¹⁶⁵ Dy, ¹⁶⁶ Ho, ¹⁷¹ Er, ¹²⁴ Sb FOR BRACHYTHERAPY USE

Abstract

The thermal neutron cross-sections (σ) of the reactions ¹⁶⁴Dy(n,γ) ¹⁶⁵Dy, ¹⁶⁵Ho(n,γ)¹⁶⁶Ho, ¹⁷⁰Er(n, γ)¹⁷¹Er, ¹²³Sb(n, γ)¹²⁴Sb were measured by the activation method. The powder samples were irradiated in an isotropic neutron field obtained from the ²⁴¹Am-Be and ²³⁹Pu-Be neutron sources, moderated with paraffin wax. The γ-ray spectra from the irradiated samples were measured by high resolution γ-ray spectrometry with a calibrated n-type Ge detector. The thermal neutron cross-sections for the reactions studied has been determined to be: for ¹⁶⁴Dy(n,γ) ¹⁶⁵Dy reaction 2400±200 barns, for ¹⁶⁵Ho(n,γ)¹⁶⁶Ho reaction 55.3±12 barns, for ¹⁷⁰Er(n, γ)¹⁷¹Er reaction 1.3±2 barns and for ¹²³Sb(n, γ)¹²⁴Sb reaction 3.5±0.5 barns. The thermal neutron cross sections for the reactions ¹⁶⁴Dy(n,γ) ¹⁶⁵Dy, ¹⁶⁵Ho(n,γ)¹⁶⁶Ho and ¹²³Sb(n, γ)¹²⁴Sb are in good agreement, within limits of uncertainty, with most of the values in the literature. The thermal neutron cross section for the reaction ¹⁷⁰Er(n, γ)¹⁷¹Er was not in good agreement with the values in the literature, but it is a measurement that has been made, and it can be evaluated again in the future.