Fig. 1.

Diagrams of the production methods of (1) ¹⁶⁶Ho and (2) ¹⁶⁶Dy. Reactor neutron activated ¹⁶⁵Ho will result in ¹⁶⁶Ho with a high purity (1). The second method is via neutron activation of ¹⁶⁴Dy by two neutrons. Dysprosium-164 has a natural abundance of 28.2% and enriched material will have a purity of over 90%. By capture of two neutrons, ¹⁶⁴Dy will be converted into ¹⁶⁶Dy which will decay into carrier-free ¹⁶⁶Ho as the daughter radionuclide (¹⁶⁶Dy/¹⁶⁶Ho generator) (data were collected from the International Atomic Energy Agency Database: https://www-nds.iaea.org/)