[en] The intermittent irradiation technique with a high voltage electron microscope was improved to meet the requirements from various types of experiments. The change of the combination of the on- and off-times of the electron beam to the next set became possible without any waiting time, and the undesired progress of the reaction during two sets of intermittent irradiations can now be avoided. The usefulness of the intermittent electron irradiation technique was demonstrated by simultaneous measurement of the growth of interstitial type dislocation loops during irradiation and by the shrinkage during the interruption of irradiation. The activation energies of both the migration of vacancies, and the self-diffusion via the vacancy mechanism were obtained from a single series of experiments. (author)