SU890077A2 - Device for measuring optical radiation flux - Google Patents

Description

one

The invention relates to photometry and can be used to accurately measure small amounts of radiation energy.

According to the main author. St. No. 614336, a device for measuring an optical radiation flux, comprising a PMT with a power supply modulator, an optical system, a source voltage modulation voltage detector, a recording instrument, an autogenerator, an amplitude high-frequency voltage detector of the autogenerator, and an input-autogenerator connected to the gap the anode-dynode of the PMT, the PMT anode is connected to the common bus of the specified power source, and the output of the oscillator through the amplitude detector of the high-frequency voltage of the oscillator is connected with a voltage torso of the modulation frequency of the power supply, the auto-oscillator is made on a common base transistor with a dual-circuit oscillatory system in the collector circuit and is equipped with a quartz resonator 1.

This device has limited sensitivity.

The purpose of the invention is to increase the sensitivity.

To achieve this goal, a device for measuring the flux of optical radiation containing a photomultiplier with a modulator of a power source, an optical system, a voltage detector of a modulation frequency of a power source, a recording device, an auto-oscillator, an amplitude detector of a high-frequency auto-oscillator voltage, an auto-oscillator input connected to the anode gap a single photomultiplier of the photomultiplier, the photomultiplier anode being connected to the common bus of the indicated power source, and the output of the autogenerator through an amplitude detector 15 The generator is connected to a voltage detector of the modulation frequency of the power supply, the oscillator is made on a common base transistor 20 with a double-circuit oscillatory system in the collector circuit and is equipped with a quartz resonator, the oscillator is made according to a circuit with a capacitive coupling with oscillating circuits in the drain

25 and the source circuit of the field-effect transistor, with the frequency-drive circuit of the excitation circuit, with a control resistor, and with two varicaps, one of which is connected to the bias circuit

Claims (1)

thirty . resistor, inductance coil and separation capacitor, the cathode of the first varicap is connected to the photomultiplier's dynode, and its anode is connected to a piezoquartz resonator, the second plate of which is connected to the gate of the field-effect transistor, the second varicap is connected in series with the separation capacitor in parallel with the oscillating circuit, the controlled resistor is turned on between the oscillating circuit of the source circuit and the source of the field-effect transistor, the gap dynode is the anode-dynode FEU through the separation circuits consisting of a resistor and The inductor is connected to the cathode of the second varicap and to the control electrode of the controlled resistor. The drawing shows a block diagram of a device for measuring the radiation flux. The device contains a PMT 1, a multiplier power supply 2, a power supply voltage modulator, an auto-oscillator 4, an amplitude detector 5 of the high-frequency auto-generator voltage, a detector 6 for the voltage modulation frequency of the power supply, and a registering device 7. capacitive coupling and piezoquartz resonator with sequential control of its frequency in the excitation circuit and tuned oscillatory circuits in the drain and source circuits, contains a field-effect transistor 8, resistors 9 and 10, voltage across its gate, inductance coil 11 and capacitor 12 forming a circuit in the drain circuit, capacitor 13 and a controlled resistor 1 forming a source auto-bias circuit, varicap 15, capacitors 16 and 17 and a high-frequency transformer 18 forming an oscillating circuit in the source circuit, piezoquartz resonator 19, varicap 20, which together with the gap form anode-dynod 2 and capacitor 22 frequency deflection tour in the oscillator excitation circuit, resistors 23 and 24 and coils 25 and 26 inductance control voltages and feedback capacitor 27. Resistors and 29 are included as a load of a high-frequency amplitude detector. The variable resistor 30 and the resistor 31 form a compensation circuit for the initial signal of the autoheterometric meter. The device works as follows. Before measuring the radiation energy flux, the auto-oscillator measure is adjusted so that the operating points of the oscillators P, 12 and 15, 16, 17, 18 are on the right slopes of the amplitude-frequency characteristics of the circuits. The autogenerator operates in continuous generation mode. When current flows through the photomultiplier, the anode-dynode 21 gap impedance changes, resulting in a change in the voltage at the photomultiplier dynode and the varicap anode 20, as well as a change in the capacitance of the anode-dynode 21. In this case, the frequency of the piezoquartz resonator is controlled 19 and the frequency of the driver circuit is increased. A change in frequency leads to a detuning of circuits 11, 12 and 15, 16, 17, 18. In this case, the equivalent resistance of the autogenerator changes. The high-frequency voltage at the output of the oscillator, which is the signal, varies. Simultaneously, the DC voltage changes across the dynode through the separator chain 23 and 25 are applied to the control electrode of the controlled resistor 14, and through the chain 24.26 to the varicap 15, which leads to a change in the value of the auto-oscillator and a sharper detuning of the circuit 15, 16, 17 and the primary winding of the transformer 18, and thus to an increase in the sensitivity of the measurements. Changes in the output of the high-frequency signal after detection by the amplitude detector 5 are fed to the input of the low-frequency detector 6, the voltage of the modulation frequency of the photocurrent and then to the registering device 7. In this invention, the use of the resistive properties of the anode-dinode photomultiplier to control the varicaps included in the frequency-creating circuit with the piezoresonator with sequential control of frequency and in the circuit of the load circuit of the autogenerating meter / as well as for controlling the resistor included in self-bias oscillator, allows to significantly increase the sensitivity of the device. The base object is a photoelectronic prefix FEP to the spectrophotometer SF-26. The technical advantages of the proposed device are higher sensitivity, simplification of the structural scheme due to elimination of the multi-stage amplifier and lower cost. The expected economic effect is primarily associated with cheaper FEP spectrophotometers by simplifying the structural diagram of the FEP and eliminating the multi-stage amplifier. Approximate calculation for one FEP gives the sum of the effect of approximately 1,300 rubles. Claims An apparatus for measuring the flux of optical radiation according to the author.