SU1343251A1 - Amplifying recording device for quantometers - Google Patents

Abstract

The invention relates to the field of optical spectral instrumentation. The aim of the invention is to improve the analysis accuracy and measurement performance. The device contains photodetectors of analytical lines and lines of comparison. Photodetectors charge storage capacitors. Voltage from storage capacitors through the keys is applied to a pulse electrometer. The signal from the electrometer goes to the logarithmizer, from which it goes to the limiting device. From the "limiting device" through the switch, the signal enters the measuring circuit, equipped with a spectral line comparison capacitor and an analytical spectral line capacitor. The difference in voltages of these capacitors goes to the anti-logifier, from the output of which the signal goes to the voltmeter. The voltage measured by a voltmeter is related to the logarithm of the concentration of the element in the sample by a linear dependence. The storage capacitors are chosen so that their capacitances are directly proportional to the spectral sensitivity of the photodetector. This proportionality is established for the analytic spectral line wavelength and the spectral line wavelength comparing the analytical pair. The device allows automatic recording of the concentration of elements in the sample. 1 hp f-ly, 1 ill. (L

Description

This invention relates to optical spectral instrumentation.

The aim of the invention is to improve the analysis accuracy and measurement performance.

The drawing shows a block diagram of the proposed device.

The device contains photodetectors 1 and 2 of the analytical spectral lines and spectral lines comparing the storage capacitors 3 and 4, the keys 5 and 6, the pulse electrometer 7, the logarithm 8, the limiting device 9, the switch 10, the measuring circuit 11, the capacitors 12 of the analytical spectral line, the capacitors 13 spectral line of comparison, anti-logarmator 14,

a voltmeter 15 and a registering device of a 20 capacitor 3 () 16. or 4 (Ui | j,). Measurement Voltages The device operates as follows: 12 capacitors (Ujg)

or 13 () is equal to lgU ,, H, U ,,.

The voltage difference across the measuring capacitors 13, i.e. voltage

at once.

During the exposure time, photodetectors 1 and 2 charge storage capacitors 3 and 4. The voltages at storage capacitors 3 and 4 are proportional to the intensities of the spectral capacitors.

25

at the entrance of the antilogarifier 14 equals

ah

To which

linky U voltage

The charge of the storage capacitor C, d is related to the photocurrent 1d and the charge time (exposure time) t by

and iatlt. ° with ,, /

Since the photocurrent 1d „is proportional to the intensity Ig of the analyzed line and the spectral sensitivity of the photocell (photomultiplier) C () is considered to be equal to

ak

, b (, „),

where K is the proportionality coefficient. Then

(J (AaH) t

and

4ah

(one)

 an

Similarly, the voltage up to which the kozar dils accumulative condensate 4 C, cf, is

and

wed

I cf

() t

WITH

(2)

wed

It is believed that.)

 4ah

wed

then, the logarithm of equation (1) and (2) and taking their ratio, get

liyi-LH- K iSi lgU, c Islep

The ratio of the logarithms of the intensities of the spectral lines is related to the concentration K (of the analyzed element in the sample by the ratio

,, sK.,. d,

where cr and d are some constants,

defined by nature

analyzed line and

lines of comparison. Given this ratio, get

ё, -А.,. «".

Since the signal at the output of the electrometer 7 is proportional to the logarithm of the input signal, the signal at the output of the logarithm 8 is proportional to the logarithm of the logarithm of the voltage on the nana input of the antilografator 14

and, ..- and,

}, ieisyi1.M IgUuf

2ai gsr

At the output of the anti-log 14, the voltage is proportional to the ratio of the logarithms of the voltages on the storage capacitors 3 and 4, i.e.

TO

.Nu

an

h7

: Ai

The voltage U, measured by a voltmeter 15, is associated with the logarithm of the concentration of an element in a sample by a linear dependence, which allows the instrument to be calibrated directly to the concentrations of the element under investigation.

As a voltmeter 15, a balanced DC amplifier with a high impedance input and one hundred percent feedback can be used.

A recording device 16 is connected to its output. The maximum value of the recording of recording device 1 is proportional to the ratio of the logarithms of the intensities of the analytical pair of lines. The record against the maximum reads the concentration of the element being analyzed, if the device is pre-calibrated according to the standards.

Measurement for several PHT elements C; It works automatically and sequentially. First, the voltage of the storage capacitor of the reference line is supplied to C

2cp

then automatic

the device sequentially does the same in turn with all accumulative ioH supplying the corresponding voltages to C; anvoltmeter 15 measures for each the ratio of logarithms of voltages

 an

Capacitors of analytical lines Q keys connecting the storage capacitors to the input of a pulse electrometer, characterized in that, in order to improve the accuracy of analysis and performance, the device additionally contains a logarithmizer and an antilogarifier, and the logarithmometer is connected between the pulse electrometer and the limiting device, and the anti-logarithm is between the measuring circuit and the voltmeter.

between it and C, cf, at the same time, the recording device records all measurements successively. The record produces a series of maxima at different levels, against which the concentration is read, if each channel is calibrated in advance according to the standards.

Claims (2)

1. A recording and amplifying device for quantometers containing photodetectors of analytical spectral lines and reference spectral lines connected to storage ring 20 2. A device according to claim 1, characterized in that the storage capacitors are selected so that their capacitances are directly proportional to the spectral sensitivity of the photodetector at the wavelength of the analytical spectral line and the wavelength of the reference spectral line that make up the analytical pair. thirty capacitors in series, a pulse electrometer, a limiting device, a switch, a measuring circuit equipped with a reference spectral line capacitor and an analytical spectral line capacitor, a voltmeter and a recording device, and 2. The device according to claim 1, characterized in that the storage capacitors are selected so that their capacitances are directly proportional to the spectral sensitivity of the photodetector at the wavelength of the analytical spectral line and the wavelength of the reference spectral line that make up the analytical pair. // Compiled by S.Ivanov Editor O.Yurkovetska Tehred M Khodanych Proofreader M.Demchik Order 4635/41 Circulation 776 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4