SU693121A1 - Method of simulating absorption bands with given parameters for testing photometric analyzers - Google Patents

Description

The invention relates to the field of absorption spectral analysis, and more specifically to the metrological assurance of industrial photometric analyzers. A known method of simulating absorption bands for verification ({uhometric analyzers, consisting in the fact that radiation is passed through reference samples LI. However, in some cases, the creation and storage of such standards is associated with great technical difficulties. In addition, they are designed for calibration of analyzers at one point of the measurement range. The closest in its technical essence to this invention is the well-known method of modeling absorption bands with specified parameters for verification ({) isometric analyzers, consisting in the fact that the radiation of a light source is passed through a narrow-band optical filter with a given absorption band.2 However, the implementation of this method is associated with the selection of substances having absorption bands similar to the analyte bands in the working spectral region. Calibration of the analyzer over the entire range requires the creation of a large number of special filters. The purpose of the invention is to provide modeling of the absorption bands in a wide spectral range. To achieve this goal, a luminous flux is formed, containing some parts of the radiation reflected from the filter and transmitted through it, and the filter does not absorb in the working region of the spectrum. In order to improve the accuracy of verification, the generated radiation is passed through a nonresonant optical filter. 369 FIG. 1 is a view of the transmittance of a narrowband filter; FIG. 2 is a view of the reflection coefficient from FIG. Figure 3 shows the dependence of the effective reflection coefficient corresponding to the distribution of the light intensity in the formed light flux over the spectrum. The intensity of the light passing through the additional filter is shown in FIG. 4 (TD). Pa figs. 5 shows a rotary device in which the proposed method of modeling absorption bands is implemented. The verification device contains a non-damped narrowband filter 1, a variable attenuator 2 and a reflecting surface 3, a light source 4, a swivel mirror 5, a collecting mirror b and a photodetector 7. As an example, consider the implementation of a method for calibrating a reflective moisture analyzer of the Apakop type. The simulation of a given absorption band is as follows. Radiation from light source 4 is reflected by mirror 5 and hits filter 1. Part of it (TD) (Fig. 1), passed through filter 1, is attenuated by attenuator 2 with transmission coefficient K / to the value K, T (l) and falls on photodetector 7. Radiation reflected from filter 1 1 - T (l) (Fig. 2), reflected from mirror 6 with reflection coefficient, is also collected on photodetector 7, while its intensity will be К2 1 T / L). The resultant on the photodetector will be proportional to T K, T (L) + K2.1 -T (L) (Fig. 3). To take into account the dependence of the background on the wavelength, radiation is additionally passed through a nonresonant optical filter (not shown in Fig. 5). The proposed method allows simple and efficient implementation of the verification of photometric analyzers for the entire measurement range. It is of particular interest for the verification of three-wave photometers, for which at present no methods of verification have been developed except for the use of primary and secondary standards. 4 formula of the invention A method of modeling absorption bands with specified parameters for verification of photometric analyzers, which means that the radiation of a light source is passed through a narrow-band optical filter, characterized in that, in order to simulate the absorption bands in a wide spectral range, a light is formed the stream containing the parts of the filter reflected from the spectrum that does not absorb in the working part of the spectrum and the radiation passing through it is then passed through an additional non-resonant optical common filter Sources of information taken into account in the examination 1. Applied IR spectroscopy. Ed. Kendall, M., Mir, 197O, p. 226. 2. US patent number 3922095, cl. 356-225, pub. 1973, (prototype).

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