Influence of Ultraviolet and Electron Radiation on Photoelectron Emission Spectra of Lead Sulfide Nanoparticles Embedded in a Matrix of Zirconium Oxide

Abstract

Lead sulfide (PbS) nanoparticles embedded in a thin-film matrix of zirconium oxide (ZrO2), ZrO2:PbS nanofilms, were studied for application in nanodosimetry of ionizing radiation. Readout of the delivered dose was carried out by measurements of photoelectron emission (PE) current from ZrO2:PbS nanofilms. PE emission was excited by UV photons having energy of 4.6-6.2 eV. First, the nanofilms were irradiated with non-ionizing UV radiation used as a model of ionizing radiation in order to extract exposure-dependent signal from PE spectra of ZrO2:PbS nanofilms. It was found that exposure-dependent signal is provided by PbS nanoparticles and it is the decrease of the increment of PE current calculated in energy range of 4.9-5.5 eV. The extracted signal was further analyzed by irradiating ZrO2:PbS nanofilms with 9 MeV electron radiation. Second degree polynomial relationship was observed between the decrease of the increment of PE spectra calculated in the energy range of 4.9-5.5 eV and dose of electron radiation in the range of 0-10 Gy. Error of dose measurement was calculated for each delivered dose. Error of dose measurement decreases from 65% to 11% when the delivered dose increases from 2 Gy to 5 Gy and doesn’t exceed 11% in the dose range of 5-10 Gy. Changes in PE spectra of ZrO2:PbS nanofilms under influence of electron radiation suggest that the nanofilms have potential to be used in nanodosimetry of ionizing radiation; however, further adjustment of the method is required to reduce dose measurement error.