OXYGEN-CONTENT OF SELECTED COALS AS DETERMINED BY CHARGED-PARTICLE ACTIVATION-ANALYSIS

Coal samples are irradiated with 3He ions to produce 11C, 13N, and 18F via the following nuclear reactions: 12C(3He, 4He)11C; 12C(3He, d)13N; 16O(3He, p)18F. By comparing the 11C to 18F production, a direct comparison of the amounts of carbon and oxygen present in the coal samples can be obtained. The 13N production provides an internal check for the amount of carbon present. In preference to calculating the yield of C-11 and F-18 on an absolute basis, organic standards with known oxygen-to-carbon ratios can be irradiated which provide a direct correlation between the 18F 11C produced and the 16O 12C originally present in the sample. By using this ratio method, the necessity for accurately known reaction cross-sections and beam fluxes is eliminated. If the standards and samples can be irradiated simultaneously, corrections for differences in saturation can be eliminated. © 1979.