BORON DETERMINATION IN SIC USING 2 INAA TECHNIQUES

Two INAA methods have been developed for the determination of boron in silicon-carbide. The first relies on the activation of B-11 by fast n eutrons to produce Li-8 by the (n,alpha) reaction. The high energy bet as emitted by Li-8 were detected with a plastic scintillator. Sensitiv ity and specificity were improved by pseudocyclic activation and beta energy selection. The second method relies on the absorption of therma l neutrons by B-10. The amount of Si in the sample is measured by INAA using fast neutrons and the Si-29(n,p)Al-29 reaction and also using t hermal neutrons and the Si-30(n,gamma)Si-31 reaction. The ratio of the two measurements is a measure of the amount of boron. Both methods we re found to have detection limits of 2 mg/g for boron in pure SiC but are subject to interferences due to impurities.