[en] Recently, both in scientific and technological fields it is extremely desirable to measure diffusion in solids at low temperatures where structural defects dominate. First, the standard technique to measure diffusion is reviewed; the most accurate measurement is commonly made by use of a radio-tracer method in combination with an appropriate serial sectioning. Second, various sectioning methods are compared with each other. It is emphasized that low diffusivity ≤ 10^-17 m²s^-1 can be measured only by the sputter-microsectioning technique. Finally, an application of rf sputter-microsectioning to measure self-diffusion in α-iron at low temperatures is presented in detail. (author)