MEASUREMENT TECHNIQUE OF BORON ISOTOPIC RATIO BY LASER-INDUCED BREAKDOWN SPECTROSCOPY

Measurement technique of isotopic ratio of boron by laser-induced brea kdown spectroscopy has been investigated. By irradiating a Q-switched nd:YAG laser onto the boron disk sample in a low pressure of ambient a ir the emission spectra of BO molecule were observed in the wavelength region from 330 nm to 560 nm. Twelve bands of the (2) Pi - (2) Sigma transition were identified bq their spectral positions and by the aid of the computer calculation code developed in this study. Each band sp ectrum observed in the experiment was well reproduced by this calculat ion code. It was found that each band spectrum consists of three wide peaks and from their relative peak heights the isotopic ratios of boro n can be evaluated. From the analysis of the (0-2) band spectrum it wa s found that the change of the relative peak heights could be detectab le using this experimental arrangement if the concentration of B-10 de creased by 5% from its natural abundance. Measurement precision can be improved by using a detection system with a spatial resolution and th is technique is expected to be a simple method of measuring the boron isotopic ratio.