SU618702A1

SU618702A1 - Magnetic field induction measuring arrangement

Info

Publication number: SU618702A1
Application number: SU762337982A
Authority: SU
Inventors: Георгий Георгиевич Слезов; Александр Михайлович Выгон; Александр Михайлович Морозов; Анатолий Николаевич Романов; Олег Владимирович Шалфеев
Original assignee: Всесоюзный Заочный Инженерно-Строительный Институт
Priority date: 1976-03-25
Filing date: 1976-03-25
Publication date: 1978-08-05

Description

1one

Изобретение относитс к электроизмерительной технике.This invention relates to electrical measuring technology.

Известно устройство дл измерени индукции магнитного пол , выполненное в виде зонда, содержащее магнитопровод в виде ферритового стержн с заостренным рабочим концом и электрические контакты в виде незамкнутых колец, расположенных на магнитопроводе 1.A device for measuring the induction of a magnetic field, made in the form of a probe, contains a magnetic core in the form of a ferrite rod with a pointed working end and electrical contacts in the form of open rings located on the magnetic core 1.

Недостаток этих устройств состоит в низ кой точности измерени .The disadvantage of these devices is low measurement accuracy.

Наиболее близко к предлагаемому устройство , содержащее магнитооптический чувствительный элемент, пол ризатор, анализатор и световоды 2.Closest to the proposed device contains a magneto-optical sensitive element, a polarizer, an analyzer and optical fibers 2.

В этом устройстве магнитооптический чувствительнь1Й элемент из вещества, обладающего константой Верде, работает при вра,щении ПЛОСКОСТИ пол ризации света, проход щего через этот элемент, когда он оказываетс в магнитном поле. Величина индукции измер емого магнитного пол определ етс по изменению интенсивности проход щего через устройство света, котора , в свою очередь, определ етс углом поворота ПЛОСКОСТИ пол ризации.In this device, the magneto-optical sensitive element of a substance possessing a Verdean constant works by rotating the PLANE by polarizing the light passing through this element when it is in a magnetic field. The magnitude of the induction of the measured magnetic field is determined by the change in intensity of the light passing through the device, which, in turn, is determined by the angle of rotation of the polarization PLANE.

Недостаток этого устройства также заключаетс в низкой точности измерени . ЭтоThe disadvantage of this device is also low measurement accuracy. it

объ сн етс зависимостью угла поворота ПЛОСКОСТИ пол ризации от длины магнитооптического чувствительного элемента и величины индукции магнитного пол .This is explained by the dependence of the angle of rotation of the PLANE of polarization on the length of the magneto-optical sensitive element and the magnitude of the magnetic field induction.

Цель изобретени - повыщение точности измерени .The purpose of the invention is to increase the measurement accuracy.

Поставленна цель достигаетс тем, что устройство ДЛЯ измерени индукции магнитного ПОЛЯ, содержащее магнитооптический чувствительный элемент, пол ризатор, анализатор и световоды, введен блок формировани градиентного магнитного пол с градиентом, совпадающим по направлению с ПОЛОСОВЫМИ доменами чувствительного элемента , выполненного в виде пластины ортоферрита с оптической осью, перпендикул рной ПЛОСКОСТИ пластин.The goal is achieved by the fact that a device for measuring the induction of a magnetic FIELD containing a magneto-optical sensitive element, a polarizer, an analyzer and optical fibers, has been introduced a block for forming a gradient magnetic field with a gradient coinciding in direction with the STRIPE domains of the sensitive element made in the form of an orthoferrite plate with an optical axis perpendicular to the PLATE of the plates.

На фиг. 1 изображена конструкци устройства; на фиг. 2 - схема, по сн юща принцип работы устройства.FIG. 1 shows the structure of the device; in fig. 2 is a diagram illustrating the principle of operation of the device.

Claims

A device for measuring the induction of a magnetic FIELD contains light guides 1, a magneto-optical sensitive element 2, a field detector 3, an analyzer 4, a gradient magnetic field forming unit 5, a housing 6, a cylinder 7 and a flexible metal sleeve 8. Use as light guides self-fibers (self-focusing light guides ) allows you to refuse focusing optics, which significantly reduces the size of the device. The light guides completely depolarize the light, which makes it possible to eliminate errors associated with the variation of the plane polarization in the light guides, as well as with the selectivity of the photomultiplier to the direction of the polarization plane. The magneto-optical sensitive element 2 is made in the form of an orthoferrite plate, and the polarizer 3 and the analyzer 4 are polioids placed in close proximity to the sensitive element. The forming unit of the gradient magnetic field 5 is made in the form of electromagnets. The EC structure is rigidly fixed in the housing 6 and placed into the cylinder 7 of a non-magnetic material, which is connected to the measuring device and a light source (for example, a laser) with the help of optical fibers 1, placed in a flexible metal sleeve 8. The device operates as follows. In the magneto-optical sensitive element 2, in the absence of an external magnetic field, a system of parallel strip domains is formed, the direction of which coincides with the projection of the axis of weak ferromagnetism on the plane of the plate. As shown in FIG. 2, when such a plate is placed in a constant magnetic field Nd, formed by a gradient magnetic field forming unit 5 with a gradient coinciding in direction with the band domains, specific wedge-shaped domains are formed in the plate, having high mobility along the projection of the axis of weak ferromagnetism on the plane of the plate. This is due to the anisotropy of the magnetic properties in the orthoferrite plate. The overlap of extremely small magnetic fields, in the order of a thousandth of Oersted, makes it possible to create a reciprocating motion of the wedge-shaped domain {"a and" b - two domain positions for different values of the external magnetic field). The beam of light transmitted through the polarizer 3 is focused by the light guide 1 onto a certain part of the plate (about 10 µm), which is partially covered by a domain with oppositely directed magnetization. After the beam passes through the orthoferrite plate, the initial polarization of the radiation due to the Farad effect is rotated by a certain angle, the magnitude of which is determined by the thickness of the plate, and the sign by the direction of the magnetic moment. The thickness of the plate is chosen depending on the material; thus, for dysprosium orthoferrite, the optimal thickness is 110 µm. Analyzer 4 is set so that it completely extinguishes the light of one polarization and transmits the radiation of another polarization. At the same time, the intensity of light entering the measuring device is determined by the displacement of the wedge-shaped domain, the high mobility of which provides an increase in the measurement accuracy. Thus, the magnitude of the magnetic field induction is determined by the change in intensity of the light passing through the device when the device is placed in a magnetic field. The introduction of a magnetic field formation unit with a gradient that coincides in direction with the stripe domains of the sensitive element, made in the form of an orthoferrite plate with an optical axis perpendicular to the plane of the plate, makes it possible to improve the measurement accuracy of the magnetic field induction in 2.62-3.13 times compared to known devices. Apparatus for measuring the induction of a magnetic saw, containing a magneto-optical sensitive element, a polarizer, an analyzer and light guides, characterized in that, in order to improve the measurement accuracy, a gradient magnetic field formation unit is introduced with a gradient that coincides in direction with the strip domains of the sensitive an element made in the form of an orthoferrite plate with an optical axis perpendicular to the plane of the plate. Sources of information taken into account in the examination: 1. USSR author's certificate number 458789, cl. G 01 R 33/00, 1973.

2. USSR author's certificate number 454511, cl. G OIR 33/00, 1973.

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