JOURNAL OF EXPERIMENTAL AND THEORETICAL PHYSICS, v. 131, no 2, page. 255-264
We present an upper limit on the flux of ultra-high-energy down-going neutrinos for E > 1018 eV derived with the nine years of data collected by the Telescope Array surface detector (from November 5, 2008 to October 5, 2017). The method is based on the multivariate analysis technique, so-called Boosted Decision Trees (BDT). Proton-neutrino classifier is built upon 16 observables related to both the properties of the shower front and the lateral distribution function.