Indra Surkova

Electron Emission Standed Nanodosimetry and Gas Detection

Photoelectron (PE) and thermostimulated exoelectron (TE) emission spectroscopies were explored for gas sensing and electron radiation nanodosimetry. Silicon substrates were in use as the working matter for benzene and isopentane sensing. PbS nanocrystals embedded in ZrO2 thin-films were employed to absorb electron radiation. Both PE and TE influenced by gas absorption and radiation deliver promising approaches for gas sensing and nanodosimetry.

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

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.