TEMPERATURE CHARACTERISTICS OF CHEMICAL EROSION OF GRAPHITE FIRST WALL

The chemical sputtering of graphite was carried out in an ultrahigh vacuum chamber of a secondary ion mass spectrometry. An incident energetic deuterium ion beam was used singly of combined with a neutralization electron beam to simulate plasma radiation. The temperature of the graphite sample was regulated from room temperature to 1 000 K.The sputtering products ranged from m/e 2～44 as a releasing molecule beam from the radiated graphite sample were analyzed in situ with a quadruple mass spectrometer SQ156. The temperature characteristic of the releasing deutero methane CD 4 from graphite SMF 800 sample bombarded by a deuterium ion beam of 1.3 μA/3keV wasobserved. The releasing peak of CD₄ due to the enhanced chemical sputtering is sited in temperatures around 780 K.