SCIENTIFIC DATA, cilt.8, sa.1, 2021 (SCI-Expanded)
The OPERA experiment was designed to discover the v(tau) appearance in a v(mu) beam, due to neutrino oscillations. The detector, located in the underground Gran Sasso Laboratory, consisted of a nuclear photographic emulsion/lead target with a mass of about 1.25 kt, complemented by electronic detectors. It was exposed from 2008 to 2012 to the CNGS beam: an almost pure v(mu) beam with a baseline of 730 km, collecting a total of 1.8 center dot 10(20) protons on target. The OPERA Collaboration eventually assessed the discovery of v(mu)-> v(tau) oscillations with a statistical significance of 6.1 sigma by observing ten v(tau) CC interaction candidates. These events have been published on the Open Data Portal at CERN. This paper provides a ydetailed description of the v(tau) data sample to make it usable by the whole community.