The proposal aims to investigate the critical dynamics of the helix structure in Fe-diluted MnGe by neutron spin echo technique. The MnGe compound has a cubic B20 structure with the lattice constant a=0.4806 nm. Its magnetic system orders below TC = 130 K in a helical structure. The scattering patterns show dramatic changes in the temperature evolution of the magnetic structure. Doping influence the magnetic system of MnGe the same as the temperature. That means that higher the Fe concentration in the compound less stable the magnetic system is. We assume that the knowledge about the main dynamical properties of Fe-diluted MnGe is the key for understanding of both critical phenomena: temperature phase transition of Ge-based compounds, and the quantum phase transition with Fe-replacement. We propose to measure the temperature and Fe-concentration dependence of the relaxation rate of the spin fluctuations. We expect to observe two characteristic timescales of the magnetic dynamics of Fe-diluted MnGe.