A signle electron, floating over the surface of liquid helium is very simple and, at the same time, very fundamental system. One can study quantum states of such system with great accuracy, since the electron suspended over helium - very homogenious and inert substance - is well isolated from the environment. One of the purpose of our project is to evaluate potential of this system as qubit - building block of a quantum computer. Suspended electron-based qubits would combine advntages of solid state (scalability, fabrication with well-established techniques, minituarization) and atomic (long decoherence time) qubits. We propose to study interaction of a suspended electron with it's enviroment, in particular with an apparatus, used to measure its quantum state.