Boron Detection in Metals by Alpha-Particle Tracking

Abstract

Track-etching techniques were used to detect boron in austenitic steels. The technique involved placing polymers which were known to be sensitive to alpha particles in intimate contact with the polished metal surface, exposing the specimen to neutrons, and then etching the polymer detector. Alpha tracks that result from the 10B(n, α)7Li reaction were developed in the polymer by etching in an aqueous NaOH solution. The boron concentration in the steels was quantitatively determined and the results compared with more conventional analytical techniques. It is seen that in addition to measuring the total boron content, the track-etch method allows one to map the distribution of boron within the microstructure of the metal alloy. The detector materials used were cellulose nitrate and cellulose acetate butyrate. The technique is useful for measuring boron concentrations in the parts-per-million range.