Optimisation of selection cuts for updated geoneutrino analysis with Borexino

The Borexino detector is a liquid scintillator detector located at the Laboratori Nazionali del Gran Sasso at a depth of 3800 meters water equivalent. Far distance from nuclear reactors and the high level of radiopurity of the liquid scintillator make Borexino ideal for geoneutrino analysis. Geoneutrinos are electron flavoured antineutrinos produced from natural radioactive decays within the Earth, and can provide direct information from the inside of our planet. Detailed study of geoneutrinos will help us to set further constraints to the current Earth models. Borexino has observed geoneutrino signal with more than 5 sigma confidence level in 2015. Thanks to improved selection criteria of inverse beta decay events in the whole data set from 2007, we expect an important increase in the total statistics. Due to a very low interaction rate of geoneutrinos, it is important to maximise the used exposure. This contribution presents the optimisation of the selection cuts crucial for the updated analysis.