抄録
With a Muller type electron microscope of ordinary evacuation system, emission patterns of nickel single crystals are observed at high temperature. Crystal faces of nickel are found divided into two groups: one is the group of faces, such as (320) face, emission of which appears in the early stage of activation, monotonously increasing with rising temperature, the other is the group of faces, such as (211) face, emission of which appears after prolonged activation treatment, with a maximum at a certain temperature. In each group, atomic packing of a face is found looser as its work function is smaller. The cause that the crystal faces become divided into two groups is discussed. Lastly, the cathode at a high temperature is quenched to room temperature while the anode voltage is being applied. The result shows that, as the activation progresses, the pattern obtained at room temperature becomes more alike what appears at high temperature and lasts
