RESUMO
Here we report the fabrication of two types of microirradiators, consisting of a recessed disk and protruding wire with low-beta-energy radionuclide Ni-63 electrodeposited onto a 25 microm diameter Pt wire. Ni-63 is constricted to a small surface area of the microelectrode; hence, this tool provides a means of delivery of localized, large dose density of beta radiation to the object but a minimal dose exposure to the user. The activity levels of Ni-63 emitted from the recessed disk and protruding wire are 0.25 and 1 Bq, respectively. The corresponding beta particles flux levels emitted from the recessed disk and protruding wire are 51 and 11 kBq/cm(2), respectively. These values, measured experimentally using liquid scintillation counting, fit very well the expected values of activity for each microirradiator, calculated considering the self-absorption effect, typical for low-energy beta particles. In order to determine the optimal configuration the dose rates for varying distances from the object were calculated.