¹⁰B/¹¹B isotopic ratio and atomic composition of boron carbide: Determination by proton induced γ-ray emission and proton elastic backscattering spectrometry

The ¹⁰B/¹¹B isotopic ratio and the atomic composition of boron carbide, an important non-metallic ceramic, have been determined non-destructively by the particle induced γ-ray emission (PIGE) and elastic backscattering spectrometry (EBS) techniques with proton beams. The analysis has been performed on powder as well as sintered ceramics containing boron in natural or ¹⁰B enriched composition. The PIGE technique, performed at a 4.0–4.2 MeV proton energy, utilizes the ¹⁰B(p,αγ)⁷Be, ¹⁰B(p,p′γ)¹⁰B and ¹¹B(p, p′γ)¹¹B nuclear reactions for (a) the isotopic analysis of boron and (b) the determination of total boron, and the ¹³C(p,p′γ)¹³C nuclear reaction for the determination of carbon. The irradiation conditions were optimized by determining the thick targets yields of prompt γ-rays, characteristic of these reactions, in the 3.0–4.2 MeV proton energy range. The quantitative analysis was performed by comparison with standards taking into account the attenuation of γ-rays in the specimens. The uncertainty in the determination of the ¹⁰B/¹¹B isotopic ratio and the B/C atomic ratio is about 2% and about 5% respectively. The analysis by EBS, on the other hand, involves the ¹⁰B(p,p)¹⁰B, ¹¹B(p,p)¹¹B and ¹²C(p,p)¹²C elastic scatterings at the 2.0 MeV proton energy. This method too yields satisfactory results. Between the two, PIGE is the method of choice for bulk analysis while EBS is useful in discerning compositional variations in surface regions. - Highlights: • ¹⁰B/¹¹B and B/C ratios in boron carbide ceramics are determined non-destructively. • The methods are particle induced γ-ray emission and elastic backscattering spectrometry with protons. • Powder and also sintered ceramics are analyzed. • Accurate and precise results are obtained. • Relative qualitative density of sintered ceramics can be obtained.