The proposal aims to investigate the critical dynamics of the helix structure in MnGe by neutron spin echo technique. The magnetic system of MnGe compound has a cubic B20 structure with the lattice constant a=0.4806 nm has ordered below TC = 130 K in a ferromagnetic spiral along the directions. The scattering patterns show dramatic changes in the temperature evolution of the magnetic structure. . A typical powder pattern, which can be observed below T = 80 K, becomes narrower and the inner part of the ring is contaminated by an additional scattering with temperature increase. The ring is smeared and the contaminating contribution inside the ring is comparable to the intensity of the ring at the critical temperature at TN = 130 K. We assume that this additional scattering has inelastic nature. Dynamics plays a crucial role in understanding of critical phenomena. We propose to measure the temperature and the wave number dependence of the relaxation rate of critical spin fluctuations. We expect to observe two crossovers in the temperature behaviour of the relaxation rate.