Oscillator strengths for resonance transitions in Na-like Kr

Abstract

The lifetime of the 3p(P(sub 3/2))-2 level in Na-like Kr(25+) was measured using beam-foil excitation and cascade corrected analysis. The Kr beam at 2 MeV/nucleon was provided by RILAC (RIKEN Linear Accelerator). The result, tau = 45 +/- 2 ps, had half the uncertainty as compared to the previous experimental data taken for highly ionized Na-like ions, and permitted an important test of theoretical methods. Recently, Hutton et al. pointed out a seemingly systematic one standard deviation difference between theoretical and experimental f-values of the 3s(S(sub 1/2))-2-3p(P(sub 3/2))-2 transitions for Na-like ions with the charge state Z greater than 20. More precise results of the study indicated that these small differences were coincidental and insignificant, confirming the reliability of theoretical calculations. A review of the scaled line strength for the 3s(S(sub 1/2))-2-3p(P(sub 3/2))-2 transition was shown in a graphical form. The measured point for Kr(25+) had no remaining discrepancy between theory and experiment.

ビーム箔励起とカスケード補正した解析を使って、Na-型Kr(25+)の3p(P(sub 3/2))-2準位の寿命を測定した。2MeV/核子のKrビームはRILAC(理研線型加速器)から取り出して行われ、τ=45±2psが得られた。この結果は多価イオン化したNa-型イオンについての以前の実験データと比較して誤差が半分であり、理論的方法の重要なテストが可能となる。最近、Huttonらは、荷電状態Z>20のNa-型イオンについて、3s(S(sub 1/2))-2-3p(P(sub 3/2))-2遷移のf-値について理論値と実験値の1σ(sub s)を系統的に指摘した。著者らのもっと正確な結果は、これらの小さな差異が偶然で重要でなく、理論計算の信頼性を確証していることを示唆している。3s(S(sub 1/2))-2-3p(P(sub 3/2))-2遷移のスケールした線強度のこれまでの結果がグラフで示され、Kr(25+)の測定値は理論と不一致がないことがわかる。