A metrological standard system for reproducing a standard field of a strong pulsed magnetic field

Abstract

The application provides a kind of method for reproducing the measurement standard system of strong pulsed magnetic field standard field by utilizing optical rotation effect light intensity ratio, the standard system solves the difficult problem that there is no measurement standard instrument for detecting and calibrating pulsed magnetic field in electron accelerator and other fields, realizes the fixed value and value traceability of pulsed magnetic field intensity. It mainly includes light emitting module, optical path control module, optical rotation module, second reflection module, light splitting module and balanced photoelectric detection module, the pulsed magnetic field standard device designed by the application is used to generate high-accuracy large-value pulsed magnetic field, is suitable for magnetic property measurement under strong pulsed magnetic field, as a standard measuring instrument, reproduces standard pulsed magnetic field, realizes the detection and calibration of instruments and equipment with strong pulsed magnetic field parameters as the core.

Description

TECHNICAL FIELD

[0001] The application provides a metrological standard system for reproducing a standard field of a strong pulsed magnetic field, and belongs to the technical field of magnetic field calibration and traceability. BACKGROUND

[0002] Under the background of the continuous development of modern measurement and testing requirements, the verification and calibration of the pulsed magnetic field parameters of high-coercivity material magnets are in urgent need of metrological standard devices for measurement and periodic verification. At present, there is a lack of strong pulsed magnetic field generating devices in China, and it is impossible to calibrate the pulsed magnetic field and trace the value, so it is necessary to establish a metrological standard device for the overall measurement and verification of the strong pulsed magnetic field. The currently disclosed methods for measuring the strong pulsed magnetic field mainly include two methods: the differential ring method and the Faraday optical rotation effect method. The differential ring method uses a coaxial cable to lead the differential ring induction signal to a recording device such as an oscilloscope. Since the rising time of the strong pulsed magnetic field is very short, which is in the order of milliseconds, a very high voltage will be induced in the differential ring, which may endanger personnel and equipment. The strong pulsed magnetic field generally has the characteristics of steep rising, short pulse duration and large amplitude. Such electromagnetic signals usually have a strong effect on the instruments and equipment in the surrounding environment in the form of conduction, radiation and the like, which may cause interference to the wires connected to the probe in the measurement device, and may also transmit high voltage to the recording device. The traditional strong pulsed magnetic field measurement device calibrates the value through the parameters of the magneto-optical medium, the measurement transducer and the like, and the operation process is complex, the measurement range is small, there are many influencing factors, the repeatability is poor, and the accuracy is low. The optical rotation effect light intensity ratio method using laser as the light source is the best choice for measuring the amplitude of the pulsed magnetic field, which does not need to contact the probe (magneto-optical medium) and can maintain a certain distance from the strong pulsed magnetic field generating device. SUMMARY

[0003] Therefore, the application provides a metrological standard system for reproducing a standard field of a strong pulsed magnetic field, which compares the standard magnetic field strength generated by the calibrated magnetic field coil with the pulsed magnetic field amplitude generated by the pulsed magnetic field standard device, so as to calibrate and trace the pulsed magnetic field standard device under the condition that the uncertainty meets the requirements.

[0004] The technical scheme of the application is as follows:

[0005] A metrological standard system for reproducing a standard field of a strong pulsed magnetic field comprises a light emitting module, a light path control module, an optical rotation module, a reflection module, a light splitting module and a balanced photoelectric detection module. The components are arranged according to the light path of the laser emitted by the light emitting module, and the laser can be received by the balanced photoelectric detection module after passing through the above-mentioned modules.

[0006] The light emitting module emits a continuous laser beam.

[0007] An optical path control module is configured to convert the laser beam from free space light to linearly polarized light.

[0008] An optical rotation module is configured to rotate the polarization plane of the linearly polarized light, and includes a first optical rotation crystal, a second optical rotation crystal, a constant magnetic field coil, a second polarizer, and a first mirror. The first optical rotation crystal is installed in the constant magnetic field coil, the second optical rotation crystal is configured to be arranged in a pulsed magnet to be measured, the second polarizer is installed between the first optical rotation crystal and the second optical rotation crystal, and the first mirror is installed on an outgoing light path of the second optical rotation crystal.

[0009] The second polarizer divides the linearly polarized light emitted by the first optical rotation crystal into first linearly polarized light and second linearly polarized light, the first linearly polarized light is directed to the light splitting module, and the second linearly polarized light is directed to the second optical rotation crystal.

[0010] A reflection module is configured to deflect the second linearly polarized light from the propagation direction to be incident on the light splitting module.

[0011] The light splitting module is configured to convert the two beams of polarized light into two beams of parallel linearly polarized light.

[0012] A balanced photodetector module is configured to calculate the intensity of the pulsed magnet to be measured based on the linearly polarized light emitted by the light splitting module.

[0013] Further, the optical path control module includes a first polarizer, a first mirror, and a G-T prism.

[0014] The first polarizer is configured to convert the laser beam from free space light to linearly polarized light.

[0015] The first mirror is configured to deflect the propagation direction of the linearly polarized light.

[0016] The G-T prism is configured to purify the degree of polarization of the linearly polarized light.

[0017] Further, the first mirror is a mirror with a reflection angle of 1°.

[0018] Further, the light splitting module includes a Wollaston prism and two mirrors. The Wollaston prism divides the first linearly polarized light and the second linearly polarized light into two beams of linearly polarized light, and the two mirrors change the propagation directions of the two beams of linearly polarized light and emit them in parallel to the balanced photodetector module.

[0019] Further, the reflection module includes two mirrors made of the same material.

[0020] Further, the optical rotation module includes the first optical rotation crystal and the second optical rotation crystal made of the same material.

[0021] Beneficial effects:

[0022] 1. The system mainly calculates the corresponding magnetic field intensity by making light pass through the same optical rotatory crystal placed in different magnetic fields. Compared with the commonly used differential ring method which uses coaxial cable to lead the differential ring induction signal to oscilloscope and other recording devices, the rising time of strong pulse magnetic field is very short, belonging to millisecond level, which can induce very high voltage in the differential ring, thus possibly endangering personnel and equipment. The system operation difficulty of the system is not high, and the safety is higher.

[0023] 2. In the optical rotation module of the system, the first optical rotation crystal and the second optical rotation crystal are made of the same material. When light passes through the medium under the action of the magnetic field, the length d of the light passing through the optical path is equal, the control variable is unique, and the calculation accuracy is higher.

[0024] 3. The optical rotation module in the system includes a 1° reflecting mirror for reflecting the laser inside the pulse magnet. The 1° reflecting angle is selected to facilitate control and avoid excessive consumption caused by large magnetic passing. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0026] Figure 1 It is a principle diagram of the pulse magnetic standard device.

[0027] Figure 2 It is a structure diagram of the pulse magnetic field standard device.

[0028] Figure 3 It is a structure diagram of the optical rotation module.

[0029] Figure 4 It is a structure diagram of the pulse magnetic field standard device. DETAILED DESCRIPTION

[0030] The embodiments of the present application will be described in detail below with reference to the drawings.

[0031] The present application proposes a kind of measurement standard device of strong pulse magnetic field standard field, principle diagram as shown in Figure 1, it includes pulse magnet 1, optical rotation module 2 and pulse magnetic field standard device 3. Figure 1As shown, a kind of metrological standard system of reproducing strong pulsed magnetic field standard field includes: light emission module, light path control module, optical rotation module, reflection module, light splitting module and balanced photoelectric detection module;Wherein, the components are arranged according to the laser light path emitted by light emission module, and laser can be received by balanced photoelectric detection module after passing the above-mentioned module;By comparing the standard magnetic field intensity generated by the magnetic field coil of the tested with the pulsed magnetic field amplitude generated by pulsed magnetic field standard device, the pulsed magnetic field standard device can be calibrated and traced in the case where the uncertainty meets the requirements.

[0032] The embodiment gives a kind of metrological standard system of reproducing strong pulsed magnetic field standard field, as shown in the attached Figure 2 As shown, it includes: light emission module 2, polarization module 3, first reflection module 4, Green Taylor prism 5, optical rotation module 6, second reflection module 7, light splitting module 8 and balanced photoelectric detection module 9;Wherein, the components are arranged according to the laser light path emitted by light emission module, and are uniformly installed on test table 1, to ensure that laser can be received by balanced photoelectric detection module after passing the above-mentioned module;

[0033] Light emission module 2 emits high collimation, low noise continuous laser beam;

[0034] Polarization module 3 changes laser beam from free-space light to linearly polarized light;

[0035] First reflection module 4 deflects the propagation direction of linearly polarized light;

[0036] Green Taylor prism 5 purifies the degree of polarization of linearly polarized light;

[0037] Optical rotation module 6 rotates the polarization plane of linearly polarized light;

[0038] Second reflection module 7 deflects the propagation direction of mixed polarized light;

[0039] Light splitting module 8 divides mixed polarized light into two single polarized light beams;

[0040] Balanced photoelectric detection module 9 receives two single polarized light beams and processes signals.

[0041] The optical rotation module, as shown in the attached Figure 3 It includes first optical rotation crystal (i.e. TGG crystal 1), second optical rotation crystal, constant magnetic field coil, polaroid and 1° mirror, first optical rotation crystal is installed in constant magnetic field coil, polaroid is installed between first optical rotation crystal and second optical rotation crystal, 1° mirror is installed on the exit light path of second optical rotation crystal, first optical rotation crystal and second optical rotation crystal are of the same material, polaroid is used to divide linearly polarized light passing through first optical rotation magnet into first linearly polarized light and second linearly polarized light, first linearly polarized light is directed to light splitting module, and second linearly polarized light is directed to second optical rotation crystal.

[0042] The second optical rotation crystal is placed in the measured pulsed magnet, and the completed embodiment system is as shown in the accompanying drawings. Figure 4

[0043] The specific working process of the system is as follows:

[0044] (1) The light emitting module 2 emits a high-collimation and low-noise laser beam. After the laser passes through the polarization module 3, it becomes linearly polarized light by free-space light, and then the transmission direction of the light beam is adjusted by the first reflection module 4, so that the laser is incident to the Gires-Taylor prism 5, and the degree of polarization of the laser is further purified.

[0045] (2) Adjust the optical path so that the polarized light passes through the optical rotation module 6, and the constant magnetic field coil and the pulsed magnetic field are turned on. The light passing through the optical rotation crystal in the constant magnetic field coil passes through the polarizer, and a first linearly polarized light is directly incident to the Wollaston prism, and a second linearly polarized light is incident to the optical rotation crystal in the pulsed magnetic field.

[0046] (3) The second linearly polarized light after optical rotation twice enters the Wollaston prism of the light splitting module 8 through the second reflection module 7, and the Wollaston prism reflects the two linearly polarized lights to the two emission mirrors and then to the balanced photodetector module 9 for signal processing.

[0047] When the light passes through the medium under the action of the magnetic field, the angle θ through which the polarization plane of the light wave turns is proportional to the length d through which the light passes in the medium and the component B of the magnetic induction intensity in the medium in the direction of light propagation, that is:

[0048] θ = V·B·d

[0049] I = I0·sin 2 (θ)

[0050] In the formula, V is called the Verdet constant, which represents the magneto-optical properties of the material, I0 represents the light intensity before the incident medium, and I represents the light intensity after the incident. The combination of the two formulas relates the light intensity and the magnetic field. After the balanced photodetector module collects the light signal to obtain the light intensity, the strength of the pulsed magnetic field is calculated by the above formula.

[0051] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical range disclosed by the present application can be easily thought of by those skilled in the art, and should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.​

Claims

1. A metrology standard system for reproducing a standard field of a strong pulsed magnetic field, characterized in that, The application relates to a light-emitting module, a light path control module, a rotating light module, a reflecting module, a light splitting module and a balanced photoelectric detection module. The light-emitting module is used for emitting a continuous laser beam. The light path control module is used for converting the laser beam from free space light into linearly polarized light. The rotating light module is used for rotating the polarization plane of the linearly polarized light and comprises a first rotating light crystal, a second rotating light crystal, a constant magnetic field coil, a second polarizer and a first mirror, the first rotating light crystal is installed in the constant magnetic field coil, the second rotating light crystal is arranged in a to-be-measured pulse magnet, the second polarizer is installed between the first rotating light crystal and the second rotating light crystal, and the first mirror is installed on an outgoing light path of the second rotating light crystal. The second polarizer divides the linearly polarized light emitted through the first rotating light crystal into first linearly polarized light and second linearly polarized light, the first linearly polarized light is emitted to the light splitting module, and the second linearly polarized light is emitted to the second rotating light crystal. The reflecting module is used for deflecting the propagation direction of the second linearly polarized light so that the second linearly polarized light is incident to the light splitting module. The light splitting module is used for converting the two linearly polarized lights into two parallel linearly polarized lights. The balanced photoelectric detection module calculates the intensity of the to-be-measured pulse magnet based on the polarized light emitted by the light splitting module. The light path control module comprises a first polarizer, a first mirror and a G-T prism.

2. The system of claim 1, wherein, The first polarizer is used for converting the laser beam from free space light into linearly polarized light. The first mirror is used for deflecting the propagation direction of the linearly polarized light. The G-T prism is used for purifying the polarization degree of the linearly polarized light. The first mirror is a mirror with a reflection angle of 1 degree.

3. The system of claim 1, wherein, The light splitting module comprises a Wollaston prism and two mirrors, the Wollaston prism divides the first linearly polarized light and the second linearly polarized light into two linearly polarized lights, the two mirrors change the propagation directions of the two linearly polarized lights and emit the two linearly polarized lights to the balanced photoelectric detection module in parallel.

4. The system of claim 1, wherein, The reflecting module is two mirrors with the same material.

5. The system of claim 1, wherein, The first rotating light crystal and the second rotating light crystal are made of the same material.

6. The system of claim 1 or 2, wherein, ​

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