Calibration Method for the Monochromator Based on Continuous Spectrum Light Source

For the inevitable errors of the monochromator in the process of producing and installing, it must be calibrated before being used. For the traditional calibration method using mercury lamp, the number of wavelengths limits the calibration precision of the monochromator. Based on the principle of grating monochromator, calibration method for the monochromator based on continuous spectrum light source is proposed. Calibration system is designed and built, which is composed of broadband light source using tungsten halogen lamp, power source, light filter, the monochromator, spectroscopy to detect the intensity of the monochromator output, and computer. Divide the intensity detected on the output of monochromator by the intensity detected directly the tungsten halogen lamp. The result is the transmissivity function of the monochromator eliminating the influence of the halogen tungsten lamp radiation and the spectrometer response function. On a certain dial number, the transmissivity function is measured, normalized and the peak wavelength is calculated. 22 groups of wavelength data and dial number are acquired. 8, 14, 18, 22 points are chosen separately to calibrate the relationship between the wavelength and the dial number of monochromator by linear fitting and quadratic fitting. Experimental results show the calibration result in 22 points is better than others, (8 points similar to the calibration method using mercury lamp). The result of quadratic fitting with 22 points as the finalresult is better than linear fitting. So the calibration method for monochromator using the continuous spectrum light source with more calibration points is superior to the traditional calibration method using mercury lamp.