Method for compensating a spectrum drift in a spectrometer

A method of compensating a spectrum drift in an optical spectrometer, the method including:

• (a) providing the optical spectrometer, the optical spectrometer:
• having a radiation source configured to generate characteristic radiation of chemical elements of an excited sample,
• (b) having a spectrum splitter configured to split up a spectrum into spectral lines according to wavelengths from the characteristic radiation,
• having a number of detectors configured, in each case, to receive a partial spectrum, and which are, in each case, provided with a plurality of pixels to measure a radiation intensity of the partial spectrum falling on the pixels, and
• having a catalogue of spectral lines of different chemical elements for use as correction lines;
• (c) generating and recording an emission spectrum of the sample;
• determining the pixels which receive the respective peak maxima of the respective partial spectrums, and identifying, in each case, a respective peak position for the respective peak maxima of the respective partial spectrums;
• (d) for each respective peak position of the respective partial spectrums:
• checking whether a correction line is present within a predefined maximum distance from the respective peak position, and calculating a distance of the respective peak position of the measured spectrum from the peak position of the adjacent correction line in the case in which it is determined that a correction line is present within the predefined maximum distance from the respective peak position;
• (e) calculating a correction function for assignment of the peak positions of the partial spectrums to the wavelengths of the measured emission spectrum;
• and
• (f) creating the catalogue of spectral lines of different chemical elements, wherein creating the catalogue comprises:
• i. carrying out a base calibration for assignment of wavelengths of radiation, contained in peaks, of a plurality of the different chemical elements, to pixels of the detectors;
• ii. determining the pixels which receive the respective maxima of the peaks for each respective partial spectrum;
• iii. identifying, in each case, a respective peak position for the respective peak maxima of the partial spectrums;
• and
• iv. creating a correction line catalogue by selecting and storing peaks that have minimum distances from adjacent peaks, and which are symmetrical with respect to their respective positions.