SU1705786A1 - Method of determining characteristics of magnetooptic converter - Google Patents

Abstract

The invention relates to metrology and is intended to certify magneto-optical measuring converters of the intensity of a pulsed magnetic field (MOIP). The goal is to increase accuracy. When implementing the method, the MOIP is exposed to magnetic field signals of various predetermined amplitudes, using the measured amplitudes and fronts of the output signals of the converter, the conversion coefficient is calculated. and a semitransparent mirror or direct modulation of the supply current of the radiator by the generator. with C

Description

This invention relates to metrology and can be used in the metrological certification of a magneto-optical measuring transducer for a pulsed magnetic field (MOIP).

The purpose of the invention is to improve accuracy.

The drawing shows a block diagram of a device for implementing a method (example).

MOIP 1 consists of optically coupled radiator 2 of optical radiation (OI) of constant power, photodetector 3, optical radiation, polaroid 4 on either side of a magneto-optical sensor (MD) 5. A recorder 6 is connected to the output of MOIP (photoreceiver output 3) electrical signal, which can be used as a pulse voltmeter or oscilloscope. MD 5 is placed in the working volume of the source 7 of a constant magnetic field (field-forming system 8) connected to the source 9 of a constant electric current. The impulse IU is fed into the optical channel of the IITD, either using a semitransparent mirror 10, which directs the impulse IU emitter 11 into the channel, or, if emitter 2 allows, by direct modulation of the supply current.

Vj

ABOUT

ate VI with about

2 emitter electric signal generator 12.

The MOIP channel must be supplied with a pulsed optical signal, exemplary in the sense of its dynamic characteristics, i.e. the front duration and the pulse width of the OI should be known. The pulse amplitude is kept constant and information about its magnitude is not required.

The method is implemented as follows.

The MD 5 is passed through a pulsed and constant IO from the emitters 2 and 11 (or from a radiator 2, the IO of which is modulated by the electrical signal of the generator 12). At the output of the photodetector (PD) 3, a signal is recorded and the duration t2 of the front and the amplitude Uo are measured at a zero magnetic field. A constant magnetic field source 7 is switched on and by varying the current of the source 9 a number of values of Hi, H2, ... Hn of the constant magnetic field is set. At the output of the FPU 3, the corresponding series of signals are recorded and their parameters are measured: Ui, L) 2, ..., Un. The change in the amplitudes of the signals at the output of the FPU 3 causes the rotation of the polarization plane of the OI propagating inside MD 5 under the action of a constant magnetic field. The constant component of the signal is not passed by the FPU 3, and the variable component is output. The corresponding mathematical processing of the obtained values of Hi, H2, ..., Hn, Ui, L) 2, ..., Un (for example, by the least squares method) makes it possible to calculate the conversion coefficient of the MOIP.

The transfer function of the MD is determined by the expression

1 rg rt

where

W (p)

(D

L is the OI path length between the input and output faces of the MD;

n is the refractive index of MD;

c is the speed of light;

p is the Laplace operator.

Using (1), one can obtain the duration ti of the rise of the front of the transient characteristic of the MD,

4 0, (2) The rise time of the front of the transient response of the MPI is determined by the dynamic characteristics of MD 5 and FPU 3, ti and t2, respectively. The t2 value is measured by the output waveform.

signal MOIP with an appropriate choice of the dynamic characteristics of a pulsed optical signal (the duration of the signal front is much less than the duration t2, the signal duration is 3-5 times longer than t2). The duration of the front of the transition characteristics MOIP can be calculated by the formula

)

Thus, as a result of the sequence of actions performed according to this method, the metrological characteristics of the MOIP can be obtained: the conversion coefficient and the rise time of the transient response front.

The error of reproduction of a constant magnetic field is about one hundredths and tenths of a percent; therefore, the proposed method can significantly reduce the component of the determination of the conversion coefficient due to the reproduction error of the amplitude of the magnetic field strength.

In addition, when using this method, the estimation of the magnitude of the random component of the MO-PI error due to the MOIP noise is simplified, since a periodic pulse signal can be used. In the prototype method, a single pulsed magnetic field signal is in principle used, which is due to the capabilities of the high-voltage pulse generator.

Claims (1)

Claim Method a magneto-optical measuring transducer, consisting in that a magneto-optic transducer sensor, penetrated by optical radiation of a constant power, is consistently fed several time signals of a magnetic field of various predetermined amplitudes, measured by the amplitude and duration of the front of the corresponding output signals of the transducer signals, according to the measured amplitudes a converter coefficient is calculated, characterized in that, in order to increase accuracy, the magneto-optical coefficient tchik signals supplied DC magnetic field sensor further permeate magneto optical radiation pulse duration and is calculated t.f front transition characteristics of transducer ratios Ф vrf + tT. where ti 0,8L n / c; L is the path length of the optical radiation between the input and output faces of the magneto-optical sensor; n is the refractive index of the material of the magneto-optical sensor; c is the speed of light; t2 is the measured length of the rise or front of the transition characteristic of the photo-receptor at the output of the converter. ten/ Y / 12