SU1509680A1 - Apparatus for spectral analysis - Google Patents

Abstract

This invention relates to optical spectral instrumentation. The aim of the invention is to improve the accuracy, reproducibility and express measurements. The radiation from the discharge chamber 1 is projected onto the entrance slit of the spectral device 4. At the output of the spectral device 4, a block of 12 photodetectors is installed. The signal from the photodetectors enters the registering unit 13. To control the position of the image of the discharge, two photosensors 3 are mounted on the entrance slit of the device 4. From these sensors 3 information about the position of the image goes to the differential amplifier 5. From the amplifier 5, the difference signal goes to a two-level comparator 6. The moment of ignition of the discharge is recorded by the sensor 10, from which the signal through the circuit 11 of the time delay enters the logic element 2 and 9. The signal from the comparator output comes to the same logic element 9 6. The output signal of the logic element 9 includes in the registering unit 13 a unit 14 of electronic switches, a block 15 of integrators, and a circuit 17 for starting the analog-digital converter. The use of the device will allow to automate the measurement process using a computer. 1 il.

Description

This invention relates to optical spectral instrumentation.

The purpose of the invention is to increase the accuracy and expressivity,

The drawing shows a block diagram of the device.

The device contains a discharge chamber 1, a projection lens 2, photosensors 3, a spectral device 4, a differential amplifier 5, two ;; level comparator 6, first 7 and: second 8 reference voltage sources, -logical element 2I 9, sensor 10 bits, time delay circuit 11, block 12 photoreceivers5 registering node 13, equipped with a block of 14 electronic keys, block 15 integrators, analog -digital converter (ADC) 16 and circuit 17 for starting the ADC. The photosensors 3 are located on both sides of the entrance slit of the spectral device 4 and are connected respectively to the inverting and non-inverting inputs of the comparator 6.

The output of the comparator 6 is connected to one of the inputs of the logic element 9. The other input of the logic element 9 is connected via a time delay circuit 8 to a 10-bit sensor, and its output is connected to the control inputs of the electronic switch unit 14, the control inputs of the integrator unit 15 and / input circuit 17 run ADC. The output of the ADC starting circuit 17 is connected to INPUT. The start of the ADC 16. The signal inputs of block 15 are connected to the outputs of block 14 of electronic keys, and the inputs of block 14 of electronic keys are the outputs of block 12 of photoelectronic multipliers, whose inputs are connected to the output of spectral device 4.

The device works as follows.

The image of the spark discharge from the discharge chamber 1 is projected by the ZOY 2 onto the spectral entrance slit. device 4, in which the light radiation is decomposed into a spectrum and through its output slits falls on a block of 12 photomultipliers. A clean image of a spark falls on photo sensors 3, whose photosignals are fed to the inputs of differential amplifier 5 ,. and carries information about the spatial position of the image of the spark discharge with respect to the entrance slit of the spectral device 4, If

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the slit is projected in the central part of the image, then both photosignals are equal to each other and there is no signal at the output of the differential amplifier 5.

If the peripheral part of the image is projected onto the slit, then the output of the amplifier 5 is a signal that is fed to a two-level comparator 6. Thus, the difference of the photosignals from the photosensors 3 indicates the portion whose image is currently projected onto the spectral instrument's input slit 4. The comparator 6 generates a resolution signal for measuring the intensity of the radiation through the logic circuit 2I-9 in the case when the selected image section is projected onto the slit. The region and its width are selected using reference voltages specified by sources 7 and 8.

When the resolution signal from the comparator 6 coincides with the signal from the sensor 10 that has passed the time delay circuit 11, the logic element 9 outputs a signal to the control inputs of the integrator unit 15 and the electronic switch unit 14, launches the ADC 16 via the load circuit 17, the trigger circuit 17 determines time delay for integrating the measured value. Time delay circuit 11 allows the selection of the initial moment of radiation detection. Number electronic switches, integrators, and analog-to-digital converters in the respective blocks depends on the number of elements measured.

Using a device for spectral analysis will allow you to automate the measurement process using a computer.

Claims (1)

Invention Formula A device for spectral analysis, containing an optically coupled discharge chamber, a projection lens, a spectral instrument with an entrance slit and a unit of photodetectors, as well as a unit of electronic switches equipped with a control input, an integrator unit equipped with a control input, analog-digital a converter equipped with a start input, an analog-to-digital converter start circuit equipped with a control input and output, a block of photodetectors via an electronic switch and an in5I block A tegrator is connected to an analog-digital converter, the output of an analog-digital converter trigger circuit is connected to an analog-digital converter trigger input, characterized in that, in order to improve accuracy and repeatability of measurements, the device additionally contains first and second photosensors, a differential amplifier, a two-level comparator , the first and second sources of the reference voltage, the logic element 2I, the discharge sensor and the time delay circuit, the first and second photosensors are installed on different the sides relative to the entrance slit of the spectral instrument so that they are optically connected with the discharge chamber through the project 9680. A tating lens, a discharge sensor is installed in the discharge chamber, the first and second photosensors are connected to the input of a differential amplifier, the output of which is connected to the two-level comparator, the first and second sources of reference voltage are respectively connected to the first and 10 second level reference inputs - the level comparator is connected to the first input of logic element 2I, the discharge sensor is connected to the second input of logic element 2I through a time delay circuit, the output of which is connected to control inputs and a block of electronic keys, integrator unit and drive circuit analog to digital converter.