K-shell photoionization of Be-like boron (B+) ions: Experiment and theory

Abstract

Absolute cross sections for the K-shell photoionization of Be-like boron ions were measured with the ion-photon merged-beams technique at the Advanced Light Source synchrotron radiation facility. High-resolution spectroscopy with E/ΔE up to 8800 (ΔE ∼ 22 meV) covered the energy ranges 193.7-194.7eV and 209-215eV. Lifetimes of the strongest resonances are determined with relative uncertainties down to approximately 4% for the broadest resonance. The measured resonance strengths are consistent with 60% 1s 22s21S ground-state and 40% 1s22s2p 3Po metastable-state ions in the primary ion beam and confirmed by comparison with independent absolute photo-recombination heavy-ion storage-ring measurements with B2 + ions using the principle of detailed balance. Experimental determination of the line width for the 1s2s 22p 1Po resonance gives a value of 47 ± 2 meV and compares favourably to a theoretical estimate of 47 meV from the R-matrix with pseudo-states (RMPS) method. The measured line widths of the 1s2s2p23P, 3D resonances are 10.0 ± 2 meV and 32 ± 3 meV, respectively, compared to RMPS theoretical estimates of 9 meV and 34 meV. © 2014 IOP Publishing Ltd.