Comparison of two experimental techniques for the determination of the 1s2s 3S metastable beam fraction in energetic B3+ ions

Two experimental techniques for the determination of the metastable 1s2s 3S fractions of two-electron ion beams are compared on the basis of their accuracy and applicability. Both techniques utilize the electron yields of the 1s2p22D and 1s2s2p 4P doubly excited states, produced in energetic collisions of two-electron ion beams with H2 targets. In the first technique, the fraction is determined in a single measurement, incorporating theoretical cross sections for the production of the doubly excited states. In the second technique, the metastable beam fraction is determined in two successive measurements at the same beam energy but with beams having different metastable fractions. Each technique suffers from the same statistical uncertainties but different systematic errors that largely affect their applicability. Results obtained from the two techniques for the B3+ case were in good agreement