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![[Figure 10]](ye5062fig10mag.jpg)
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Figure 10
Operating parameters for the DXAS instrument with focus-to-crystal distance (p) set to 1.5 m and X-ray divergence (ω) fixed at 1.2 mrad by the KB mirrors for (a–d) Si(111) and (e–h) Si(220) analyzer crystals. (a, e) The bending radii (R) of the polychromators at different energies. In the orange region, the R values are determined by matching the energy spread of the polychromator to that of ML 48 where possible without reducing the radius below a minimum value of 0.3 m. In the red region, the R values are chosen so that the total energy resolutions [shown in (d) and (h)] do not exceed the K-shell core-hole lifetime broadening. (b, f) The crystal-to-detector distances (u) at different energies. In the purple region, the u values are determined by constraining the Bragg beam size to 28 mm so that the pixel array detector can capture the entire Bragg beam. In the blue region, u is fixed at 2.5 m so as not to exceed the hutch's spatial constraints. (c, g) The energy bandwidths of the DXAS polychromators in comparison with the ML 48 bandwidth. (d, h) The corresponding energy resolutions of the DXAS instrument in the operating energy ranges of ML 48 (4.9 keV to 10.7 keV) in comparison with the K-shell core-hole lifetime broadening, which is obtained from Campbell & Papp (2001  ). |
![[Figure 10]](ye5062fig10.jpg)
 | JOURNAL OF SYNCHROTRON RADIATION |
ISSN: 1600-5775
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