[en] In this report the authors present the first experimental results from measurements of films obtained using the 2-m liquid-hydrogen bubble chamber open-quotes Ludmilaclose quotes of the High Energy Laboratory of the Joint Institute for Nuclear Research. The chamber was exposed in a beam of antideuterons with momentum 12.2 GeV/c. The hadronic background in the beam was about 40 ± 10% and was mainly due to π^- mesons. A tantalum 3-mm thick plate was placed inside the working volume of the chamber. As the interaction, the authors considered an event with the multiplicity of secondary charged particles n_ch ≥ 2. 5 refs., 3 figs., 1 tab