An apparatus includes a crystal analyzer positioned relative to an x-ray source on a Rowland circle. The crystal analyzer includes crystal planes curved along at least one direction and configured to receive x-rays from the x-ray source and to disperse the received x-rays according to Bragg's law. The apparatus further includes a spatially resolving detector that includes a plurality of x-ray detection elements having a tunable first x-ray energy and/or a tunable second x-ray energy. The plurality of x-ray detection elements are configured to measure received dispersed x-rays having x-ray energies below the first x-ray energy while suppressing measurements above the first x-ray energy and/or to measure the received dispersed x-rays having x-ray energies above the second x-ray energy while suppressing measurements below the second x-ray energy.