RU1827550C - Method for determination of wave length of spectral line - Google Patents

Abstract

A method for determining the wavelength of spectral lines, which consists in registering the spectrum with a multi-element photodetector, finding the distance between the elements of the photodetector with maximum intensities of the reference and definable spectral lines and finding the detectable wavelength according to the formula Ax Ai ± (). P. 2 ill., 2 tablets

Description

The invention relates to spectral analysis and may find application in emission and atomic absorption measurements using multi-element photodetectors.

An object of the invention is to increase the accuracy of determining the wavelength for a detectable and reference line.

Figure 1 schematically shows an embodiment of a spectral device for implementing a method for determining a wavelength of spectral lines; Fig. 2 shows two sections of a multi-element photodetector with an image of signal values corresponding to the intensities of the reference and definable spectral lines.

The method is implemented as follows: by means of a radiation source 1 through a slit 2 illuminates a dispersing element 3 of a spectral device, decomposing the radiation into a spectrum, which is recorded using a multi-element photodetector 4 located in the focal plane of the spectral device. The signal from the photodetector 4 enters the information processing device 5 (e.g., a computer) and is displayed as the numbers of the photodetector elements with its signal values on the indicator device 6.

The wavelength of the determined spectral line is determined as follows.

The spectrum of the test sample is excited. The spectrum is recorded with a multi-element photodetector. The values of the signals from all the elements of the photodetector are successively measured, the numbers of the elements of the photodetector for which signals from maximum to background values are recorded for the detected and reference lines are recorded. The exact positions of the intensities maxima of the reference and determined spectral lines are determined. The wavelength of the determined spectral line is found.

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Example. The methods for determining the wavelength of the spectral line were compared by the method described in the prototype and proposed. We used a mock spectrograph with a nonclassical diffraction grating with an average inverse linear value

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dispersion 0.22A (element). The width of the entrance slit was set equal to 0.05 mm.

The radiation source was a hollow cathode lamp on a nickel element with an IPS-01 power source. A lensless lighting system was used. The spectrum was recorded with a multi-element solid state photodetector containing 500 elements. The dimensions of the element pad are 0.026x0.5 mm. The obtained data were averaged from 5 values and displayed on the monitor screen in the form of numbers of photodetector elements with the signal value on them, and the increase in the sequence numbers corresponded to the increase in the wavelengths of the spectral lines.

As a reference, a spectral line with a wavelength

3012.00A (3).

Table 1 shows the wavelengths of the spectral lines and the corresponding numbers of photodetector elements with the values of the signals on them.

Table 2 shows the comparative data of wavelengths of spectral lines, determined in a known manner and proposed.

From a consideration of Table 2 it is seen that the absolute error in determining the wavelength of the proposed method in comparison with the known one decreases by 1.2-1.5 times.

Using the proposed method for determining the wavelength of spectral lines will reduce measurement errors and improve accuracy.

Claims (1)

SUMMARY OF THE INVENTION A method for determining a wavelength of a spectral line, including excitation of a spectrum of a sample, using a multi-element photodetector consisting of X elements to register the spectrum, recording maximum intensities of the detected and reference spectral lines, determining the distances Ki and Kg between the first element of the photodetector and elements recording the maximum intensities of the determined and reference spectral lines, and finding the wavelength Ax of the determined line from the formula Ax Ai ± (K2-Ki) P, where Ai is the wavelength of the reference line; P is the average value of the inverse linear dispersion; in a selected section of wavelengths per width of one element of the photodetector, with the exception of the fact that, in order to To improve accuracy, for the detected and reference lines, the values of signals from all elements of the photodetector are successively measured, the numbers of the elements of the photodetector for which the maximum and background signal values for the detected and reference lines are recorded, and K2 and Ki are calculated from the ratios: 0 k, AC-fo KJ Baj-Bij where, 2, while corresponds to a definite line, 2 reference lines, NMatfCj, WMOKC; 2 Mmax7 Mach; GU; GA; EX; Y, E 0 # WMQKC 5 D2 / NMQHCL / ™ Male. .2 M;, ГXi- (rX0  V j Nqojy. Ј Y; Z x2-Ј .. A; NPIQKC, Np, aKCf Wmancj Fw. (E x; G tak-ii Mokcj. Read NMDKJJ xt Y, -E Y; E x,, f, j AT r xf-rr- x,) g 4 " 5 V T---Ј .u-Ј xiKCj niaKCf WtnoKCi. N 2 / Phg. -Vis. N2 (GX;) wrrjQKc HmaiKCf Vv 0 NMSKCJ — photodetector element numbers with maximum signal values; , are the numbers of the elements of the photodetector with the background values of the signals; 5 j | - the magnitude of the signal from the 1st element of the photodetector (NI ....); Nl NMaKCj N (N2) N (- NMSKCJ Table 1 table 2 ®- , -i .. .  , J J- A / pzjf FIG. 2. 7 tfpjz. s, l / f, z g / - Ј.