UHV compatibility of two possible fusion reactor materials: K-ramic/sup R/ and ATJ graphite

Outgassing characteristics of K-ramic/sup R/ (manufactured by Kaman Nuclear) and ATJ graphite were evaluated under various treatments. For K-ramic, total outgassing rates of 2 x 10-9 Torr l s-1 cm-2 unbaked and 7 x 10-11 Torr l s-1 cm-2 baked were measured. Mass spectroscopic measurements showed H2 and CO to be the dominant residual gases. For ATJ, graphite the treatment consisted of repeated heatings in vacuo to 1250 K as well as repeated exposures to atmosphere. Residual gas analysis measured the time dependence of desorbed quantities of H2, H2O, CO2, CO, and CH4. During the initial heating, the maximum species atom to lattice atom ratios were obtained yielding values of 2.6 x 10-6 for H2, 3.4 x 10-5 for H2O, 1.6 x 10-5 for CO2, 7.6 x 10-6 for CO, and 5.2 x 10-6 for CH4. The toalt outgassed material from the graphite sample decreased by a factor of 103 after successive heatings