Problem of Reduction of the Quantum State’s Vector

This article presents an investigation of problem of quantum system state’s measurement by using an example of particles registered by a measuring device (screen). Some variants of R-procedure which is responsible for measurements are discussed. New variant of R-procedure is suggested. It is based on quantum description of measuring device (screen). In frame of this model R-procedure can be described as part of unitary evolution of the whole system “particle + screen”.