Systems and methods for characterizing films by X-ray photoelectron spectroscopy (XPS) are disclosed. For example, a system for characterizing a film may include an X-ray source for generating an X-ray beam having an energy below the k-edge of silicon. A sample holder may be included for positioning a sample in a pathway of the X-ray beam. A first detector may be included for collecting an XPS signal generated by bombarding the sample with the X-ray beam. A second detector may be included for collecting an X-ray fluorescence (XRF) signal generated by bombarding the sample with the X-ray beam. Monitoring/estimation of the primary X-ray flux at the analysis site may be provided by X-ray flux detectors near and at the analysis site. Both XRF and XPS signals may be normalized to the (estimated) primary X-ray flux to enable film thickness or dose measurement without the need to employ signal intensity ratios.