Local Determination of Carbon by Combining Beta-Autoradiography and Electron Microprobe Analysis

The methods of β-autoradiography and electron microprobe analysis were used for the determination of low carbon concentrations in synthetic silicate glasses produced at high pressure and temperature. Before the experiments the β-particle emitting radioactive isotope 14C was introduced into the samples. A reference sample of basaltic composition containing 19 μg/g of 14C was prepared. P-type Russian nuclear emulsion plates (10–20 μm thickness) were used. Electron microprobe was employed for measurement of the Ag Lα line intensity. Silver is generated as a result of exposure of the nuclear emulsion to 14C-decay β-particles and subsequent development. The detection limit of this technique is 0.2 μg/g for a scanned area of 50 × 50 |im2 and 3 μg/g for a scanned area of 5 × 5 μm2.