an illumination source configured to generate an amount of electromagnetic radiation including an amount of soft x-ray radiation;

an illumination optics subsystem disposed in an illumination optical path between the illumination source and a specimen under measurement, the illumination optics subsystem including one or more x-ray illumination optical elements configured to direct the amount of soft x-ray radiation from the illumination source to an illumination spot on the specimen under measurement, wherein a length of the illumination optical path from the illumination source to the specimen under measurement is less than 2 meters, and wherein the one or more x-ray illumination optical elements focus the amount of soft x-ray radiation onto the illumination spot with a demagnification factor of at least 1.25, the illumination optics subsystem including an internal field stop disposed in the illumination optical path, the internal field stop conjugate to the illumination source and the specimen under measurement;

an x-ray detector configured to detect an amount of x-ray radiation scattered from the specimen under measurement in response to the amount of soft x-ray radiation focused onto the illumination spot; and

a computing system configured to determine a value of a parameter of interest characterizing a structure disposed on the specimen based on the detected amount of x-ray radiation.