Dynamic calibration method for echelle spectrometer in laser-induced breakdown spectroscopy

A dynamic calibration method for echelle spectrometer in laser-induced breakdown spectroscopy, comprising:

• S1:
• by using an echelle spectrometer, collecting a spectrogram of a standard calibration light source, and getting spectral wavelengths in different orders according to the spectrogram;
• S2:
• based on information about the spectral wavelengths in different orders obtained in the step S1, and in combination with a corresponding calibration function ƒ(x,y), calculating a pixel position coordinate ({circumflex over (x)},ŷ) corresponding to a spectral wavelength ŵ of a certain analysis element,
• where x and y respectively represent original pixel horizontal and vertical coordinates of an analysis element on the echelle spectrometer, and {circumflex over (x)} and ŷ respectively represent pixel horizontal and vertical coordinates corresponding to a spectral wavelength ŵ of a certain analysis element on the echelle spectrometer;
• S3:
• by using the echelle spectrometer, collecting laser-induced plasma spectra corresponding to the above analysis element in a sample to be tested, performing dynamic searching and filtering near the pixel position coordinate ({circumflex over (x)},ŷ) obtained in the step S2 to obtain a set D of all selected pixel position coordinates, and adjusting all original intensity values in the set D to obtain adjusted intensity values expressed by an adjustment function F(Ix,y),
• where Ix,y represents a spectral line intensity value at the pixel position coordinate (x,y), and x and y in the pixel position coordinate (x,y) in the set D respectively have lower limit values of in and n, and respectively have upper limit values of m′ and n′;
• and
• S4:
• by using the adjusted intensity values F(Ix,y) obtained in the step S3, calculating a spectral line intensity value at the spectral wavelength ŵ after dynamic calibration according to the following formula:
• Îŵ=Σx,y=m,nm′n′F(Ix,y), which is used as the spectral line intensity value at the wavelength ŵ of the analysis element, so that the dynamic calibration for the given spectral line of the echelle spectrometer is completed,
• where Ix,y represents a spectral line intensity value at the pixel position coordinate (x,y) on the echelle spectrometer, the function F is an adjustment function, Îŵ represents a spectral line intensity value corresponding to the spectral wavelength ŵ after calibration and Σ is a sum function.