Fig. 1. The SAO microcalorimeter and other X-ray instruments attached to the NIST EBIT. An X-ray lens (lower left insert), designed at SAO, focuses the X-rays emitted from the highly charged ions of the EBIT onto the detector chips of the microcalorimeter.

Fig. 2. Comparison of the simulated spectrum of the Perseus Galaxy Cluster with an experimental EBIT spectrum using the SAO microcalorimeter.

Fig. 3. Emission lines originating from transitions between the 2p^6 1S₀ ground state and the 2p⁵3s ¹P₁, ³P₁, ³P₂ and 2p⁵3d ¹P₁, ³D₁, ³P₁ excited states of Fe¹⁶⁺.

Fig. 4. Comparison of the Chandra Fe¹⁶⁺ spectra of Xi Uma and Capella [32]. The labelled 2p⁵3d ¹P₁ electric dipole line appears to have different relative intensities with respect to other lines in the two spectra.

Fig. 5. X-ray spectra produced in Kr³⁵⁺ (top) and Kr³⁶⁺ (bottom) ions colliding with Ar atoms. Peaks in the 13–17 keV region correspond to K X-rays, those in the 2.3–5 keV region correspond to L X-rays, and those at <2 keV correspond to M X-rays. Note that a peak at 13 keV in the spectrum from Kr³⁶⁺ ion collisions is due to K X-rays from Kr³⁴⁺ ions which are formed through double electron capture (but not due to double collisions).

Table 1. Typical operating parameters of the NIST EBIT