Sagittal focusing of undulator radiation is shown to be compatible with the proposed inclined double-crystal monochromator geometry for heat load reduction. The focusing aberrations are found to be negligible for typical undulator-beam divergences over a range of magnifications from 1:2 to 6:1 and energies from 3 to 40 keV. The inclined geometry reduces the required signal sagittal curvature of the focusing crystal compared to focusing with conventional symmetric crystals; hence, focusing is possible at higher X-ray energies and with less anticlastic bending. In addition, anticlastic stiffening ribs project a smaller footprint to the beam so that the achievable focal spot size is potentially better than with conventional symmetrically cut crystals. 16 refs.
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