Absolute calibration of the efficiency of a VUV-monochromator/detector system in the range 110 - 450 nm

Abstract

For determining the efficiency of a vacuum-UV monochromator with a multiplier type PMT-142 in the range 110 - 450 nm two different methods for absolute and six methods for relative calibrations were used. The results of all relative calibrations except for one agree to within an accuracy close to the experimental error in the range of their mutual overlap. The accuracies of the relative efficiency curves were found to be 18, 14, 7, 3, 6 and 10% for the ranges 110 - 120, 120 - 140, 140 - 250, 250 - 350, 350 - 400, and 400 - 450 nm, respectively. Absolute calibrations were performed at 147 and nm with an accuracy of 8% in both cases. The differences in the grating illuminations at the monochromator applications and in the calibration were taken into account. The influences of the accuracies of all operations necessary for the absolute calibration on the overall calibration error were thoroughly analysed. If there are significant differences between the geometries of the system illumination during calibration and during application, they may be the main source of error.