DETECTOR CALIBRATION IN THE 10-60 NM SPECTRAL RANGE AT THE ELECTROTECHNICAL LABORATORY

The method for detector calibrations, in the 10-60 nm spectral range, make use, at the Electrotechnical Laboratory, of a specific rare-gas ion chamber as a primary standard detector. One of the features of this ion chamber is its four stage ion collectors. Only the second and the third-stage ion currents are used for the calibration since the first and the fourth-stage measured ion currents are lower than the one predicted by our model. Moreover, for shorter wavelengths, correction factors for the secondary ionization were determined experimentally. A silicon photodiode was then calibrated as a secondary standard detector. The calibration results agreed to a model calculation within +/- 10 %. Uncertainty in the calibration was estimated to be within +/- 9 %.