DEVELOPMENT OF A DRIFT-CORRECTION PROCEDURE FOR A DIRECT-READING SPECTROMETER

摘要

This procedure provides automatic correction for drifts in the radiometric sensitivity of each detector channel in a direct-reading emission spectrometer. Such drifts are customarily con¬trolled by the regular analyses of standards, which provide corrections for changes in the excitational, optical, and electronic components of the instrument. This standardization proce¬dure, however, corrects for the optical and electronic drifts. It is a step that must be taken if the time, effort, and cost of processing standards is to be minimized. This method of radi-ometric drift correction uses a 1000-W tungsten-halogen reference lamp to illuminate each de¬tector through the same optical path as that traversed during sample analysis. The responses of the detector channels to this reference light are regularly compared with channel responses to the same light intensity at the time of analytical calibration in order to determine and correct for drift. Except for placing the lamp in position, the procedure is fully automated and com¬pensates for changes in spectral intensity due to variations in lamp current. A discussion of the implementation of this drift-correction system is included.