ABSOLUTE CALIBRATION OF THE EFFICIENCY OF A VUV-MONOCHROMATOR DETECTOR SYSTEM IN THE RANGE 110-450-NM/

For determining the efficiency of a vacuum-UV monochromator with a mul tiplier type PMT-142 in the range 110-450 nm two different methods for absolute and six methods for relative calibrations were used. The res ults of all relative calibrations except for one agree to within an ac curacy close to the experimental error in the range of their mutual ov erlap. 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, 2 50-350, 350-400, and 400-450 nm, respectively. Absolute calibrations w ere performed at 147 and 364 +/- 2 nm with an accuracy of 8% in both c ases. The differences in the grating illuminations at the monochromato r applications and in the calibration were taken into account. The inf luences 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 s ystem illumination during calibration and during application, they may be the main source of error.