Deuterium retention of carbon dust (II). Effect of crystal structure and form

Deuterium retention of carbon dust was investigated by two methods, i.e. one is deuterium gas absorption and the other is deuterium ion irradiation. After the gas absorption, retained deuterium desorbed in forms of D2 and HD. Saturated amount of retained deuterium due to the gas absorption at 100 Pa was approximately 10-3 in the atomic ratio D/C, when the temperature range was from 973 K to 1173 K. This amount was 10 or 100 larger than that of powdered graphite or bulk graphite, respectively. However, trapping energy of deuterium in the carbon dust was 0.22 eV, almost the same as that of the graphite. After the deuterium ion irradiation to the carbon dust, the retained deuterium desorbed in forms of D2, HD, CD4 and C2D4. The amount of retained deuterium due to the deuterium ion irradiation was 0.55 in the atomic ratio D/C, almost same as the graphite. (author)