A superfluid helium film can host a variety of exotic quantum phenomena, such as the topological Berezinskii–Kosterlitz–Thouless transition, Rollins film flow and “Third sound”. Earlier, we proposed an experimental set-up based on a standard silicon wafer (RB1510035), which allowed us to observe (5 months ago) for the first time 163 Å thick 4He and 0.1% 3He/4He mixture films formed on a silicon surface, using the neutron reflectometer POLREF. In our experiment we were able to observe and study several quantum liquid effects previously observed by other methods. However, taking into account the importance of these results, and our ambition to publish it in a highly rated journal, we need to repeat these measurements to prove the reproducibility of reflectivity density profiles of superfluid He mixture film obtained in the earlier experiment.