Various computer-implemented methods and systems are provided. One computer-implemented method includes determining a ratio between output signals generated by detecting spectra for a single event in two or more detection windows. The spectra are characteristic of different materials. At least a portion of the spectra overlap in at least one of the two or more detection windows. The method also includes determining which of the different materials are associated with the ratio. One embodiment of a system includes one or more detectors configured to detect spectra for a single event in two or more detection windows. The spectra may include spectra as described above. The one or more detectors are also configured to generate output signals in response to the detected spectra. The system also includes a processor configured to determine a ratio between the output signals and to determine which of the different materials are associated with the ratio.