Resonance strength for KLL dielectronic recombination of hydrogenlike krypton

We report KLL dielectronic recombination (DR) resonance strength for hydrogenlike krypton ${\mathrm{Kr}}^{35+}$ measured with an electron-beam ion trap. X rays emitted from both DR and radiative recombination (RR) are observed as a function of electron-beam energy over the KLL resonances. The DR resonance strength is obtained by normalizing the DR x-ray counts to theoretical RR cross sections. The experimental strength is shown to agree with theoretical strength calculated using the flexible atomic code.

Figure 1

Schematic illustration of the KLL DR process into a hydrogenlike ion.

Figure 2

Time sequence for the electron-beam energy scan. In the present experiment, t${}_1$, t${}_2$, t${}_3$, and t${}_4$ was 2 s, 8 s, 10 ms, and 90 ms, respectively.

Figure 3

Scatter plot of x-ray intensity as functions of x-ray and electron energy.

Figure 4

Experimental excitation function of KLL DR (black dot) and the theoretical resonance function fitted to the experimental data (red curve).

Figure 5

Comparison between the theory and experiment.

Figure 6

Resonance strengths for the KLL resonance of hydrogenlike ions. The solid red circles are the present theoretical results and the open black circles are the previous theoretical results for He${}^{+}$ [31], O${}^{7+}$ [32], Ti${}^{22+}$ [15], and U${}^{91+}$ [33]. The black squares with error bars are experimental results for He${}^{+}$ [34], O${}^{7+}$ [35], Ti${}^{22+}$ [15], Kr${}^{35+}$ (present), and U${}^{91+}$ [33].