SU1509625A1 - Device for measuring intensity of line in optical spectrum - Google Patents

Abstract

This invention relates to optical spectral instrumentation. The aim of the invention is to increase the temporal resolution. The device is based on a monochromator with an electromagnetic drive 5, an output slit 7 and auxiliary output slots 8 and 9. These auxiliary slits are located so that they distinguish spectral regions that are ahead and delayed relative to the slit 7. Photodetectors 10-12 are installed behind each slit. The photodetectors 11 and 12 are connected to the command generation unit 14, which allows the search for a line within the spectral interval specified by the measurement boundary setting unit 19. The electromagnetic drive 5 controls the block 21. At the recorder 23, the line intensity and the current wavelength information coming from the calibration unit 22 are recorded simultaneously. The time resolution of the device is governed by the constant time of the photodetector and recorder, as well as the speed of the circuit to track the center of the line at maximum displacement rates of ≤ ^{10 4} nm / s. The instrument adjusts to the line even if only the wing of the line is in the spectral range covered by the auxiliary slots. 4 il.

Description

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and retarding with respect to the slit 7. Photodetectors 10-12 are installed behind each slit. Photodetectors 11 and 12 are connected to command generation unit 14, which allows searching within the spectral interval specified by the unit. 1 9 set the boundaries of the measurements. Electromagnetic actuator 5 is controlled by block 21. At recorder 23, the line intensity and information about the current

the wavelength coming from the device 22 graduations. The time resolution of the device's ability is regulated by the constant time of the photodetector and recorder, as well as by the speed of the tracking system of the center of the lines at maximum displacement rates g: 1 О nm / s. The instrument adjusts to the line even if only the wing of the line is in the spectral range covered by the auxiliary slots. 4 il.

This invention relates to optical spectral instrumentation.

The aim of the invention is to increase the temporal resolution.

FIG. I shows the block diagram of the device; in fig. 2 is a diagram of the formation of fine tuning commands in FIG. 3 - block diagram of setting the boundaries of measurements; in fig. 4 is a diagram of the control unit of the scanning device.

The device contains (Fig. 1) an entrance slit 1, a collimator 2, a dispersing element 3, a flat scanning mirror 4 with an electro-magnetic scanning drive 5, a focusing lens 6, a main slit 7 (measuring channel) and two auxiliary slits 8 and 9 with photoreception kami 10-12, two beam splitters 13 and the beam splitters 13 of the auxiliary slits 8 and 9 are installed with the possibility of separating images of spectral regions shifted in the direction of advance (on slit 8) and retarding (on slit 9) in relation to the image on the main optical slits 7 for equal spectral intervals, shaper 14 fine tuning commands, generator 15, two logic elements 2I-ZI-OR 16 and 17, reversible counter 18, measurement boundaries setting unit 19, RS flip-flop 20, scanning device control unit 21 , the device 22 for calibration and the recorder 23, while the electrical outputs of the photodetectors 11 and 12 are connected respectively to the first and second inputs of the shaper 14 fine tuning commands, the first and second outputs of which are connected to the first inputs of the corresponding logic elements 2I-3. LIs 16 and 17, and the third to the fifth inputs of these logic elements, the second and fourth inputs of which are connected to the generator outputs 15, and the outputs to the corresponding counting inputs of the reversing counter 18, the outputs of which are connected to the corresponding inputs of the scanner control unit 21, connected by the output to the electrical input of the electromagnetic actuator 9 scanning, and the unit 19 for setting the boundaries of measurements, the first and second outputs of which are connected respectively to the R and S inputs of the RS flip-flop 20, the direct input of which is connected en to the third input of the first logic element 2I-ZI-OR

16, and inverse - to the third input of the second logic element 2И-ЗИ-ИЛ

17. The electrical output of the photodetector 10 is connected to the first input of the recorder 23, and the electrical output of the calibration device 22 is connected to the second input of the recorder 23.

Shaper 14 fine tuning commands contains (FIG. 2) difference adder 24, comparators 25 and 26, 27 and 28. with sources 29-32 of the reference voltage and two logic elements 2I 33 and 34, with the first input of block 14 connected to the primary ( summing) the input of the differential adder 24 and with the non-inverting input of the comparator 25, the inverting input of which is connected to the output of the source of the reference voltage, the second input

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unit 2A is connected to the second (subtractive) input of the differential adder 24 and the non-inverting input of the comparator 26, the inverting input of which is connected to the output of the source of the reference voltage 30, the output of the differential adder 24 is connected to the non-inverting input of the comparator 27, the inverting input of which is connected to the output of the source 31 the reference voltage, and with the inverting input of the comparator 28, the non-inverting input of which is connected to the output of the source 32 of the reference voltage, the outputs of the comparators 27 and 28 are connected to the second inputs according to 2I 33 and 34, the first input of the 2I logic element 33 is connected to the output of the comparator 25 and the first input of the element 2IL-HE 35, the output of which is the third output of the block 14, the first input of the logic element 2I 34 is connected to the output of the comparator 26 and the second the input of logic element 2 and 33 is the first output of block 14, and the output of logic element 2I of element 34 is the second output of block 14.

Measurement boundaries unit 18 (FIG. 3) consists of a code converter 36, containing a decoder 37 and logic elements OR 38 and SHW-HE 39, while the inputs of the decoder 37 are inputs of block 19, and the outputs are connected to the corresponding inputs of logic elements OR 38 and OR-NOT 39, the outputs of the logic elements OR 38 are connected to the inputs of the switch 40, and the outputs of the logical elements OR-NOT 39 are connected to the inputs of the switch 41, the outputs of the switches 40 and 41 are the first and second outputs of the block 19, respectively.

The scanner control unit 21 (Fig. 4) contains a digital-to-analog converter (DAC) 42, the digital control inputs of which are the inputs of the block 21, the reference voltage source 43, the output of which is connected to the information input of the DAC 42, the operational amplifier 44, the reverse circuit of which includes an analog input and an output of a D / A converter 42, a power amplifier 45, the input of which is connected to the output of an operational amplifier 44, and the output is the output of a block 21.

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elements, consisting of the PAP DZ and the operational amplifier 44, forms a controlled digital attenuator 46.

A graduation device 22 (FIG. 1) consists of a radiation source 47, a condenser 48, a slit diaphragm 49, a projection lens 50, a flat scanning mirror 51 rigidly connected to the scanning mirror 4, a flat fixed mirror 52 located opposite the scanning mirror 51, the collimator 53, the matrix photodetector 54, connected by the output through the driver 55 to the inputs of the encoder 56, connected by an output to the second input of the recorder 23.

The device works in the following way.

The radiation flux through the entrance slit 1 enters the collimator 2 and through the dispersing element 3, the flat scanning mirror 4, the lens 6, the beam splitters 13 and the output slit 7 enters the optical input of the photodetector 10 of the main channel. At the same time, reflecting from the light dividers 13, the radiation flux falls on auxiliary output slots 8 and 9 and photoreceptions II and 12, and the images on auxiliary slots 8 and 9 are shifted along the wavelengths in the direction of advance (in the slot 8) and in the direction of lag ( on the slit 9) with respect to the image of the spectrum on the main slit 7 at equal spectral intervals D.

The process of setting up the device on the line is divided into two stages (modes) of operation.

At the first stage, a search is performed in automatic mode for a line within the spectral interval, the boundaries of which are set by the operator before the experiment using switches 40 and 41 of block 19, at the second stage the device is precisely tuned to the center of the line with subsequent tracking of the center of the line when shifts occur the position of the maximum line during the experiment. In this case, it is possible that the superposition of the signals of photodetectors 11 and 12 is such that the device starts working immediately from the second stage.

When the device is turned on, the starting position of the scanning element

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This - mirrors 4 is determined by the state of the counter 18, arbitrarily set when the power supply voltage of the elements of the device circuit is turned on. The digital combination with the output of counter 18 is fed to a digital input of a digital-to-analog converter (D / A converter) 42 connected by analog inputs and a feedback circuit of operational amplifier 44 and the output signal of operational amplifier 44 is uniquely determined by a digital code. The output signal of the operational amplifier 4A through the power amplifier 46 is fed to the electromagnetic scanning actuator 5, which is set to the position corresponding to the digital code of the counter 18. The mode selection, i.e. The first or second stage of operation of the device is carried out by block 14 on the superposition of electrical signals of photodetectors 11 and 12, depending on the distribution of energy in auxiliary slots 8 and 9, located as well as the slot 7 of the main photodetector 10 in the image plane of the spectrum. In the absence of a line or its fragments within the spectral interval

   L - A, corresponding to the location of the auxiliary slots 8 and 9, the outputs of the comparators 25 and 26 are in the state of logical zero, the output of the logical element 2OR-NO 35 - in the state of logical unit, the outputs of the logical elements 2I 33 and 34 in the state, logical zero and pulses from the output of the generator 15 are fed to the corresponding input of counter 18 (summing or subtracting) through one of the logical elements 2I-ZI-OR} 6 or 17, depending on the status of RS-trigger RS 20. The direction of rotation of the scanning mirror 4 is determined is starting state of RS-trig ger outputs 20, wherein the pulses output from the generator 15, receives the summing or subtracting input of counter 18 outputs pulses from the counter 18 receives a control unit 21 the scanning device. Changing the output voltage of block 21 causes. a corresponding change in the position of the scanning mirror 4. At the same time, the output pulses of the counter 18 are fed to a converter of 36 codes,

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the outputs of which form a position code corresponding to the position of the scanning mirror 4 at the current time. When the position code at the outputs of the 36 KOjqoB converter coincides with the position of the corresponding switch 40 or 41, the R- or S-input of the RS-flip-flop 20 receives a signal that changes its state, which causes the counting inputs to be switched (summing or charging) counter 18 and a corresponding change in the increment of the output digital values at its outputs. The latter causes a reverse movement of the scanning device 5. The scanning process in the entire range specified by the operator, in the absence of a line or its fragments, continues continuously until the line appears in the wavelength interval specified by the operator.

The appearance of a line (or its fragments) in a given spectral interval causes the transition of one of the comparators 25 and 26 or both of these comparators (if the image of the line appeared near the slots of the auxiliary photodetectors II and 12) to a single state. At the same time, the output of the logical element IPI-NO 35 is set to the state of logical zero and subcircuits. GOs of both logical elements 2I-ZI-OR 16 and 17 are blocked, i.e. the output pulses of the generator 15 cannot pass to the counting inputs of the counter 18 regardless of the state of the RS flip-flop 20. Further control of the direction of movement of the scanning device is carried out only by block 14. Depending on the ratio of the signals of the photodetectors 11 and 12, the output signal of the difference adder 24 can have a positive or negative polarity. In this case, one of the comparators 27 or 28 is triggered and the output signal of this comparator is fed through the corresponding logic element 2I 33 or 34 to the first input of the corresponding logic element ZI-2I-OR 16 or 17 and the output pulses of the generator 15 are directed to the corresponding counter (summing or subtracting) the input of the counter 18. The changing digital output of the counter 18 is converted by block 21 and causes a change of position

scanning mirror 4 up until the signals from the outputs of the photodetectors 11 and 12 will not be equal in magnitude. In this case, the signal from the output of the differential adder 24 becomes less than the response voltage of the comparators 27 and 28, and the outputs of both comparators are set to a logical zero state, the first inputs of the logical elements ZI-2I-IZh 16 and 17 receive a logic zero level that blocks the passage pulses of the generator 15 to the counting inputs of the counter 18. The installation of the line to the center is completed.

In case of a subsequent discrepancy in the course of the experiment, the center of the line with the center of adjustment of the slit 7, the corresponding comparator 27 or 28 connects the generator 15 to the corresponding counting input of the counter 18 and an adjustment occurs to the center of the line.

To detect the current wavelength value, the light flux of radiation source 47 through condenser 38, slit diaphragm 49 and projection lens 5.0 is directed to a flat scanning mirror 51. After multiple reflections between a flat scanning mirror 51 and a fixed mirror 52, the flow is directed by the collimator 53 to matrix photodetector 54. The electric signal of the matrix photodetector 54 through the driver 55 and the encoder 56 is fed to the second input of the recorder 23, the first input of which receives the signal of the photodetector 10. Thus Thus, during the experiment, the radiation intensity at the line maximum and the current value of the maximum wavelength are recorded by the recorder. It should be noted that the device automatically adjusts to the spectral line even if its initial maximum is outside the interval specified by the operator, provided that even a wing of this line falls into the specified spectral interval.

The time resolution of the device is governed by the time constant of the photodetector (10 s) and the recorder (10 s when using an analog-digital converter with a digital operational storage) as a recorder.

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Claims (1)

device or high-speed analog storage device on a feed tape with an amplitude-modulated recording channel) and speed of the line center tracking system (10 s) at maximum line center displacement speeds (due to Stark or Doppler effects) relative to the output slit in the process of researching non-stationary objects. .10 them / s. Invention Formula A device for measuring the intensity of a line in an optical spectrum, containing optically coupled monochromator, equipped with an electromagnetic drive scanned by an annunciator, a graduation device, a main exit slit, and first and second auxiliary output slits, installed with the possibility of spectral portions shifted in the direction of advancing and delays on equal spectral intervals with respect to the part of the spectrum emitted by the main exit slit, the main photodetector set at the main output first and second auxiliary photodetectors installed behind the first and second auxiliary output slots, respectively, as well as a recorder connected to the main photodetector and a graduation device, which, in order to improve the time resolution, the device additionally contains a block forming fine tuning commands, equipped with first and second inputs and first, second and third outputs, generator, first and second logic elements 2И-ЗИ-И, reversible counter, control unit sk tweening element, equipped with code inputs and output, unit for setting measurement boundaries, equipped with code inputs and first and second outputs, and RS-Tpiirrep, the first and second auxiliary photodetectors connected to the first and second inputs of the fine tuning command generation unit, the first and second the outputs of which are connected to the first inputs of the first and second logic elements 2I-ZI-OR, respectively, the generator is connected to the second and fourth inputs of the first and second logic elements 211-ZI-NZ the third output of the fine tuning command tuning unit is connected to the front of the first and second logic elements 2I-ZI-OR, the outputs of which are connected to the counting inputs of the reversible counter, the output of the reversing counter connected to the code inputs of the control unit of the scanning element and the unit for setting the boundaries of measurements first and second the outputs of the measurement boundaries block are connected respectively to the R- and S-input of the RS flip-flop, the direct output of which is connected to the third input of the first logic element 2И-ЗИ-И and the inverse one - for the third input of the second logic element 2И-ЗИ-OR, output the control unit of the scanning element is connected to the electromagnetic. scanned drive. Phie.