A magnetic field measuring device and method for electromagnetic pulses in a system

Abstract

The present invention aims to solve the technical problem that the existing electromagnetic pulse test environment generated by a pulsed ray source is complex and harsh, and that the test is difficult and the measurement methods are limited, resulting in a scarcity of available experimental data. The present invention provides a magnetic field measurement device and method for electromagnetic pulses within the system. The device generates electromagnetic pulses within the system by irradiating a metal cavity with pulsed rays within a vacuum-resistant cavity, protects the magnetic field detector with a shielding lead plate, transmits the magnetic field signal of the metal cavity to an optical receiver via an optical fiber, and records the measurement signal with an oscilloscope, thereby simulating the magnetic field measurement of the electromagnetic pulse within the system. The device achieves the measurement of pulsed magnetic field signals in an environment where photoelectrons and rays coexist. The effective acquisition of the measurement signal is of great significance for verifying the accuracy of the theoretical calculation model of the electromagnetic pulse within the system and understanding the laws of the electromagnetic pulse within the system.

Description

Technical Field

[0001] The present invention relates to the technical field of pulse radiation detection, and in particular to a magnetic field measuring device and a measuring method of an electromagnetic pulse in a system. Background Art

[0002] Pulsed x-rays and gamma-rays irradiating materials will form photoelectrons. When the rays irradiate a metal cavity, the movement of the photoelectrons and the rebalancing of the charge of the cavity structure will excite electromagnetic pulses inside the cavity. The industry calls this "intra-system electromagnetic pulses."

[0003] Electromagnetic pulses within a system are difficult to effectively shield and can directly affect cables, circuits, or components within the device housing, causing interference or damage. Currently, electromagnetic pulses within systems are a hot topic in the field of radiation effects. Numerical simulation is an important research method in this area, but relevant experimental data is very scarce. Using pulsed radiation sources to measure electromagnetic pulses within systems and using experimental results to verify the accuracy of numerical models is of great significance.

[0004] When an x-ray or gamma-ray source irradiates a metal cavity to generate electromagnetic pulses within the system, photoelectrons and x-rays or gamma-rays that penetrate the cavity are also generated inside. This complex and harsh environment makes it very difficult to measure the electromagnetic pulses within the system. In the experiment, the signal-to-noise ratio of the response signal of the electric field or magnetic detector is very low, and may even be completely submerged in the noise. Therefore, being able to accurately obtain the electric field or magnetic field signal of the electromagnetic pulse within the system becomes the key. Summary of the Invention

[0005] The purpose of the present invention is to solve the technical problems that the electromagnetic pulse testing environment in the system generated by the existing pulse ray source is complex and harsh, and the available experimental data is scarce due to the difficulty of the test and limited measurement methods. By providing a magnetic field measurement device and measurement method for the electromagnetic pulse in the system.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A magnetic field measuring device for electromagnetic pulses in a system, which is special in that it comprises a vacuum-resistant cavity, a metal cavity arranged in the vacuum-resistant cavity, a shielding lead plate and a magnetic field detector, and an optical receiver and an oscilloscope connected in sequence;

[0008] A flange is installed at one end of the vacuum-resistant cavity, which is connected to the output end of the pulse ray source. An optical fiber flange is installed at the other end of the vacuum-resistant cavity, which is used to connect one end of the optical fiber to the outer wall of the vacuum-resistant cavity. A vacuum evacuation pipe is left in the cavity wall of the vacuum-resistant cavity.

[0009] The metal cavity is arranged in the radiation direction of the pulse ray source and is provided with an opening;

[0010] The shielding lead plate is arranged in the vacuum resistant cavity near the pulse radiation source and is located in the gap between the inner wall of the vacuum resistant cavity and the outer wall of the metal cavity, and is used to shield the magnetic field detector from direct radiation.

[0011] The output end of the magnetic field detector is connected to the other end of the optical fiber, and the magnetic field probe of the magnetic field detector is embedded in the metal cavity from the opening;

[0012] The input end of the optical receiver is connected to one end of the optical fiber, and is used to convert the optical signal output by the magnetic field detector into an electrical signal and output it to the oscilloscope to display and record the measurement signal.

[0013] Furthermore, the magnetic field probe of the magnetic field detector includes a metal shielding shell, a first magnetoresistive circuit board arranged on the side wall of the metal shielding shell, a second magnetoresistive circuit board arranged in the metal shielding shell, a magnetoresistive chip soldered to the first magnetoresistive circuit board, a differential circuit, an amplification and filtering circuit, and an electro-optical conversion circuit soldered to the second magnetoresistive circuit board, and an IPEX coaxial cable for connecting the circuits; the output end of the magnetoresistive chip is connected to the input end of the differential circuit via the IPEX coaxial cable, and the output end of the electro-optical conversion circuit is connected to the other end of the optical fiber;

[0014] After the magnetoresistive chip senses the environmental magnetic field signal, it outputs two opposite signals. The two opposite signals are sent to the differential circuit to eliminate common-mode interference. The differential signal is then conditioned by the amplification and filtering circuit. The amplified signal is sent to the electro-optical conversion circuit to be modulated into an optical signal and then output.

[0015] Furthermore, the magnetoresistive chip is of a differential output type, based on a Wheatstone bridge structure, whose magnetic sensitive axis coincides with the direction of the measured magnetic field, and includes four magnetic sensitive resistors with the same resistance value, namely resistor R1, resistor R2, resistor R3 and resistor R4, wherein resistor R1 is connected in series with resistor R2, resistor R3 is connected in series with resistor R4, the other ends of resistor R1 and resistor R4 are both connected to the positive terminal of the power supply, and the other ends of resistor R2 and resistor R3 are both connected to the negative terminal of the power supply; the magnetic sensitive directions of the resistors R1 and R3 are the same and the same as the direction of the measured magnetic field, the magnetic sensitive directions of the resistors R2 and R4 are the same, and the magnetic sensitive directions of the resistors R1 and R2 are opposite; the connection point between the resistors R1 and R2, and the resistors R3 and R4 respectively output two opposite signals, namely a positive output signal and a negative output signal;

[0016] The magnitudes of the two opposite signals output by the magnetoresistive chip are:

[0017]

[0018] Among them, V out+is the positive output signal of the magnetoresistive chip, V out- is the negative output signal of the magnetoresistive chip; V CC is the supply voltage for the magnetoresistive chip; R is the resistance value of the magnetoresistive resistor; ΔR is the change in the resistance value of the magnetoresistive resistor affected by the magnetic field.

[0019] Furthermore, the differential circuit uses an instrumentation amplifier; the amplification and filtering circuit uses a high-frequency operational amplifier to construct a proportional amplification circuit to amplify the measurement signal; and the electro-optical conversion circuit uses a DFB laser to perform electro-optical conversion on the conditioned measurement signal.

[0020] Furthermore, one end of the metal cavity close to the pulse ray source is made of a metal material with high electrical conductivity, such as gold, silver or copper, and the other opposite end is paved with a graphite plate for absorbing photoelectrons.

[0021] Furthermore, the metal cavity in the vacuum-resistant cavity is a cylindrical structure, and the shielding lead plate is annular and has a thickness of not less than 2 cm.

[0022] Furthermore, an insulating bracket is included, which is used to insulate and fix the metal cavity in the vacuum-resistant cavity.

[0023] The present invention also provides a method for measuring the magnetic field of an electromagnetic pulse in a system, based on the above-mentioned magnetic field measuring device of an electromagnetic pulse in a system, characterized by comprising the following steps:

[0024] Step 1: Place the metal cavity in the vacuum-resistant cavity using an insulating bracket, ensuring that the metal cavity is aligned with the output port of the pulse radiation source, and fix the magnetic field detector at the opening of the metal cavity;

[0025] Step 2: placing an annular shielding lead plate in the gap between the inner wall of the vacuum-resistant cavity and the outer wall of the metal cavity to shield and protect the magnetic field detector;

[0026] Step 3: Use optical fiber to connect the magnetic field detector to the optical fiber flange of the vacuum-resistant cavity, and then connect the optical receiver and oscilloscope in sequence;

[0027] Step 4: tightly connect the pulse radiation source to the flange on the vacuum-resistant chamber;

[0028] Step 5: Remove the air from the vacuum chamber through the vacuum pipe to prevent the radiation from colliding with the air to generate secondary electrons, which will affect the magnetic field environment.

[0029] Step 6: Turn on the pulsed ray source to emit x-rays or gamma-rays;

[0030] Step 7: The magnetic field probe of the magnetic field detector measures the magnetic field signal in the metal cavity, transmits it to the optical receiver through the optical fiber, and displays and records the measured waveform through the oscilloscope.

[0031] Compared with the prior art, the present invention has the following beneficial technical effects:

[0032] 1. The magnetic field measurement device for electromagnetic pulses within a system provided by the present invention generates electromagnetic pulses within the system by irradiating a metal cavity with pulsed rays in a vacuum-resistant cavity, protects the magnetic field detector with a shielding lead plate, transmits the magnetic field signal of the metal cavity to an optical receiver via an optical fiber, and records the measurement signal using an oscilloscope to simulate the magnetic field measurement of the electromagnetic pulses within the system.

[0033] 2. The electromagnetic pulse magnetic field measurement device provided by the present invention first creates a vacuum environment to prevent the generation of secondary electrons by the interaction between radiation and air. Secondly, it utilizes a metal cavity to excite more photoelectrons, enhancing the field strength of the magnetic field signal. The graphite plate on the metal cavity absorbs the photoelectrons, preventing the impact of reverse photoelectrons on the field environment. Then, the annular lead plate shields the direct radiation exposure of the magnetic field detector, ensuring the normal operation of the detector. Finally, the magnetic field detector signal is transmitted via optical fiber, avoiding the problem of secondary interference from radiation during signal transmission of traditional coaxial cables. Therefore, the electromagnetic pulse magnetic field measurement device in the system can ensure measurement accuracy in complex and harsh radiation environments.

[0034] 3. The magnetic field probe in the magnetic field measurement device of the electromagnetic pulse in the system provided by the present invention minimizes the coupling path of external interference in its structural design, suppresses the common-mode interference brought by the external measurement environment through signal differentiation, and further improves the signal-to-noise ratio of the measurement signal through signal conditioning of amplification and filtering. It can be used for pulse magnetic field signal measurement in a radiation environment and has the advantages of large dynamic range, high sensitivity, and compact structure.

[0035] 4. The magnetic field measurement method of the electromagnetic pulse in the system provided by the present invention is based on the magnetic field measurement device of the electromagnetic pulse in the system, which realizes the measurement of the pulse magnetic field signal in an environment where photoelectrons and rays coexist. The effective acquisition of the measurement signal is of great significance for verifying the accuracy of the theoretical calculation model of the electromagnetic pulse in the system and mastering the laws of the electromagnetic pulse in the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the structure of the magnetic field measurement device of the electromagnetic pulse in the system of the present invention;

[0037] Figure 2 Schematic diagram of the structure of the shielding lead plate in an embodiment of the present invention;

[0038] Figure 3 Schematic diagram of the structure of the magnetic field probe of the magnetic field detector in an embodiment of the present invention;

[0039] Figure 4Schematic diagram of the structural principle of the magnetoresistive chip in an embodiment of the present invention;

[0040] Figure 5 This is a pulsed magnetic field waveform diagram inside a metal cavity measured using the present invention under an X-ray accelerator;

[0041] Reference numerals:

[0042] 1-vacuum-resistant chamber, 2-insulating bracket, 3-metal chamber, 4-shielding lead plate, 5-magnetic field detector, 6-optical fiber, 7-flange, 8-vacuum pipe, 9-optical receiver, 10-oscilloscope, 11-optical fiber flange;

[0043] 51 - first magnetoresistive circuit board, 52 - magnetoresistive chip, 53 - metal shielding shell, 54 - second magnetoresistive circuit board, 55 - IPEX coaxial cable. DETAILED DESCRIPTION

[0044] To make the objects, advantages and features of the present invention more clear, the magnetic field measuring device and method of electromagnetic pulses in a system proposed by the present invention are further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0046] like Figure 1 As shown, this embodiment provides a magnetic field measurement device for electromagnetic pulses in a system, including a vacuum-resistant cavity 1, a metal cavity 3, a shielding lead plate 4 and a magnetic field detector 5 arranged in the vacuum-resistant cavity 1, as well as an optical receiver 9 and an oscilloscope 10.

[0047] The vacuum-resistant cavity 1 is a cylinder with a flange 7 installed at one end, which is connected to the output end of the pulse ray source, and an optical fiber flange 11 installed at the other end, which is used to lead out the magnetic field test signal of the magnetic field detector 5 through the optical fiber 6. A vacuum pumping pipe 8 is left on the wall of the vacuum-resistant cavity 1.

[0048] The metal cavity 3 is also cylindrical and is fixed to the vacuum-resistant chamber 1 by two insulating brackets 2. Its radius is smaller than that of the vacuum-resistant chamber 1. The cover plate near the end of the pulse radiation source is made of a metal with high conductivity (preferably copper) to stimulate more photoelectrons within the vacuum-resistant chamber 1 and maximize the magnetic field signal within the metal cavity 3. A graphite plate is laid on the opposite end to absorb photoelectrons and prevent the impact of reverse photoelectrons on the field environment. The cylindrical wall of the metal cavity 3 has an opening facing upward, and the magnetic field probe of the magnetic field detector 5 is embedded in the cavity through the opening.

[0049] like Figure 2As shown, the shielding lead plate 4 is annular and has a thickness of not less than 2 cm. It is located close to the pulse radiation source and in the gap between the inner wall of the vacuum-resistant cavity 1 and the outer wall of the metal cavity 3 to shield the magnetic field detector 5 from direct radiation.

[0050] The magnetic field detector 5 is located behind the shielding lead plate 4. The magnetic field probe of its magnetic induction component is a magnetoresistive chip based on differential output. The differential circuit can eliminate the common-mode interference of the external environment and output it through the optical fiber 6 to avoid interference from the external environment when transmitting signals through traditional coaxial cables.

[0051] The optical receiver 9 is used to convert the optical signal output by the magnetic field detector 5 into an electrical signal and output the electrical signal to the oscilloscope 10 to display and record the measurement signal.

[0052] like Figure 3 As shown, the magnetic field probe of the magnetic field detector 5 includes a metal shielding shell 53, a first magnetoresistive circuit board 51 arranged on the side wall of the metal shielding shell 53, a second magnetoresistive circuit board 54 arranged in the metal shielding shell 53, a magnetoresistive chip 52 welded on the first magnetoresistive circuit board 51, a differential circuit, an amplification and filtering circuit and an electro-optical conversion circuit welded on the second magnetoresistive circuit board 54 connected in sequence, and an IPEX coaxial cable 55 for connecting the circuits; the output end of the magnetoresistive chip 52 is connected to the input end of the differential circuit through the IPEX coaxial cable 55, and the output end of the electro-optical conversion circuit is connected to the other end of the optical fiber 6.

[0053] After the magnetoresistive chip 52 senses the ambient magnetic field signal, it outputs two opposite signals. The two opposite signals are sent to the differential circuit to eliminate common-mode interference. The differential signal is then conditioned by the amplification and filtering circuit. The amplified signal is sent to the electro-optical conversion circuit to be modulated into an optical signal, and finally output through the optical fiber 6.

[0054] The magnetoresistive chip 52 is of differential output type and is internally based on a Wheatstone bridge structure. Its magnetic sensitive axis coincides with the direction of the measured magnetic field and can output two differential signals of equal amplitude and opposite direction as the external magnetic field changes.

[0055] like Figure 4As shown, the magnetoresistive chip 2 selected in this embodiment uses four sensitive resistors to form a push-pull Wheatstone bridge structure, namely resistor R1, resistor R2, resistor R3 and resistor R4, wherein resistor R1 is connected in series with resistor R2, and resistor R3 is connected in series with resistor R4. The other ends of resistors R1 and R4 are both connected to the positive terminal of the power supply, and the other ends of resistors R2 and R3 are both connected to the negative terminal of the power supply. The magnetic sensitivity directions of resistors R1 and R3 are the same and the same as the direction of the measured magnetic field. The magnetic sensitivity directions of resistors R2 and R4 are the same, and the magnetic sensitivity directions of resistors R1 and R2 are opposite. The connection point between resistors R1 and R2 and resistors R3 and R4 respectively output two opposite signals, namely a positive output signal and a negative output signal, wherein:

[0056]

[0057] Among them, V out+ is the positive output signal of the magnetoresistive chip, V out- is the negative output signal of the magnetoresistive chip; V CC is the supply voltage for the magnetoresistive chip; R is the resistance value of the magnetoresistive resistor; ΔR is the change in the resistance value of the magnetoresistive resistor affected by the magnetic field.

[0058] The differential circuit's non-inverting and inverting inputs are both high-impedance inputs, tracking or amplifying the differential output signal and possessing strong drive capability. When the two input signals are subtracted, if the same interference is superimposed on them, they can theoretically cancel each other out, doubling the useful signal.

[0059] In this embodiment, the differential circuit uses an instrumentation amplifier, the amplification and filtering circuit uses a high-frequency operational amplifier to construct a proportional amplifier circuit to amplify the measurement signal, and the electro-optical conversion circuit uses a DFB laser to perform electro-optical conversion on the conditioned measurement signal. Finally, the measurement signal is output through the optical fiber 6 to prevent the coaxial cable from being interfered with during the signal transmission process.

[0060] This embodiment further provides a method for measuring the magnetic field of an electromagnetic pulse within a system based on the magnetic field measuring device of the electromagnetic pulse within the system, comprising the following steps:

[0061] Step 1: Place the metal cavity 3 in the vacuum-resistant cavity 1 through the insulating bracket 2, ensure that the metal cavity 3 is aligned with the output port of the pulse radiation source, and fix the magnetic field detector 5 at the opening position of the metal cavity 3;

[0062] Step 2: placing an annular shielding lead plate 4 in the gap between the inner wall of the vacuum-resistant cavity 1 and the outer wall of the metal cavity 3 to shield and protect the magnetic field detector 5;

[0063] Step 3: Use the optical fiber 6 to connect the magnetic field detector 5 to the optical fiber flange 11 of the vacuum chamber 1, and then connect the optical receiver 9 and the oscilloscope 10 in sequence;

[0064] Step 4: tightly connect the pulse radiation source to the flange 7 on the vacuum chamber 1;

[0065] Step 5: The air in the vacuum chamber 1 is evacuated through the vacuum pipe 8 to prevent the radiation from colliding with the air to generate secondary electrons, which would affect the magnetic field environment.

[0066] Step 6: Turn on the pulsed ray source to emit x-rays or gamma-rays;

[0067] Step 7: The magnetic field probe of the magnetic field detector 5 measures the magnetic field signal in the metal cavity 3 , transmits the signal to the optical receiver 9 via the optical fiber 6 , and displays and records the measured waveform via the oscilloscope 10 .

[0068] like Figure 5 As shown in the figure, the pulsed magnetic field waveform in a cylindrical cavity is measured using the above-mentioned measuring device under an X-ray accelerator. It can be seen that the measurement result directly gives the signal waveform of the pulsed magnetic field to be measured, and the waveform characteristics and peak magnetic field intensity are in good agreement with the theoretical calculation results, and the measurement results are relatively ideal.

[0069] In summary, the magnetic field measurement device and measurement method of electromagnetic pulses in the system provided by the present invention generate electromagnetic pulses in the system by irradiating a metal cavity with pulsed rays in a vacuum-resistant cavity, protect the magnetic field detector with a shielding lead plate, transmit the magnetic field signal of the metal cavity to an optical receiver through an optical fiber, and record the measurement signal through an oscilloscope, thereby realizing the measurement of pulsed magnetic field signals in an environment where photoelectrons and rays coexist. The effective acquisition of the measurement signal lays the foundation for verifying the accuracy of the theoretical calculation model of the electromagnetic pulse in the system.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A magnetic field measuring device for electromagnetic pulses within a system, characterized by: It comprises a vacuum-resistant cavity (1), a metal cavity (3) arranged in the vacuum-resistant cavity (1), a shielding lead plate (4) and a magnetic field detector (5), and an optical receiver (9) and an oscilloscope (10) connected in sequence; A flange (7) is installed at one end of the vacuum-resistant cavity (1), and the flange (7) is connected to the output end of the pulse ray source; an optical fiber flange (11) is installed at the other end of the vacuum-resistant cavity (1), and the optical fiber flange (11) is used to connect one end of the optical fiber (6) to the outer wall of the vacuum-resistant cavity (1); and a vacuum evacuation pipe (8) is left on the cavity wall of the vacuum-resistant cavity (1); The metal cavity (3) is arranged in the radiation direction of the pulse ray source and is provided with an opening; The shielding lead plate (4) is arranged in the vacuum-resistant cavity (1) near the pulse radiation source and is located in the gap between the inner wall of the vacuum-resistant cavity (1) and the outer wall of the metal cavity (3), and is used to shield the magnetic field detector (5) from direct radiation exposure. The output end of the magnetic field detector (5) is connected to the other end of the optical fiber (6), and the magnetic field probe of the magnetic field detector (5) is embedded in the metal cavity (3) from the opening; The input end of the optical receiver (9) is connected to one end of the optical fiber (6) and is used to convert the optical signal output by the magnetic field detector (5) into an electrical signal and output it to the oscilloscope (10) to display and record the measurement signal.

2. The magnetic field measuring device of electromagnetic pulses in a system according to claim 1, characterized in that: The magnetic field probe of the magnetic field detector (5) comprises a metal shielding shell (53), a first magnetoresistive circuit board (51) arranged on the side wall of the metal shielding shell (53), a second magnetoresistive circuit board (54) arranged in the metal shielding shell (53), a magnetoresistive chip (52) welded on the first magnetoresistive circuit board (51), a differential circuit, an amplifying and filtering circuit, and an electro-optical conversion circuit welded on the second magnetoresistive circuit board (54) and connected in sequence, and an IPEX coaxial cable (55) for connecting the circuits; the output end of the magnetoresistive chip (52) is connected to the input end of the differential circuit via the IPEX coaxial cable (55), and the output end of the electro-optical conversion circuit is connected to the other end of the optical fiber (6); After sensing the environmental magnetic field signal, the magnetoresistive chip (52) outputs two opposite signals, which are sent to a differential circuit to eliminate common-mode interference. The differential signal is then conditioned by an amplifying and filtering circuit, and the amplified signal is sent to an electro-optical conversion circuit to be modulated into an optical signal and then output.

3. The magnetic field measuring device of electromagnetic pulses in a system according to claim 2, characterized in that: The magnetoresistive chip (52) is of a differential output type, based on a Wheatstone bridge structure, wherein its magnetic sensitive axis coincides with the direction of the measured magnetic field, and comprises four magnetic sensitive resistors with the same resistance value, namely resistor R1, resistor R2, resistor R3 and resistor R4, wherein resistor R1 is connected in series with resistor R2, resistor R3 is connected in series with resistor R4, the other ends of resistor R1 and resistor R4 are both connected to the positive end of the power supply, and the other ends of resistor R2 and resistor R3 are both connected to the negative end of the power supply; the magnetic sensitive directions of resistors R1 and R3 are the same and the same as the direction of the measured magnetic field, the magnetic sensitive directions of resistors R2 and resistor R4 are the same, and the magnetic sensitive directions of resistors R1 and R2 are opposite; the connection point between resistors R1 and R2, and resistors R3 and R4 respectively output two opposite signals, namely a positive output signal and a negative output signal; The magnitudes of the two opposite signals output by the magnetoresistive chip (52) are respectively: Among them, V out+ is the positive output signal of the magnetoresistive chip, V out- is the negative output signal of the magnetoresistive chip; V CC is the supply voltage for the magnetoresistive chip; R is the resistance value of the magnetoresistive resistor; ΔR is the change in the resistance value of the magnetoresistive resistor affected by the magnetic field.

4. The magnetic field measuring device of electromagnetic pulses in a system according to claim 3, characterized in that: The differential circuit uses an instrumentation amplifier; the amplification and filtering circuit uses a high-frequency operational amplifier to construct a proportional amplification circuit to amplify the measurement signal; and the electro-optical conversion circuit uses a DFB laser to perform electro-optical conversion on the conditioned measurement signal.

5. The magnetic field measuring device of electromagnetic pulses in a system according to any one of claims 1 to 4, characterized in that: The metal cavity (3) has one end close to the pulse ray source and is made of a metal material such as gold, silver or copper, and the other end opposite thereto is paved with a graphite plate for absorbing photoelectrons.

6. The magnetic field measuring device of electromagnetic pulses in a system according to claim 5, characterized in that: The metal cavity (3) in the vacuum-resistant cavity (1) is a cylindrical structure, and the shielding lead plate (4) is annular and has a thickness of not less than 2 cm.

7. The magnetic field measuring device of electromagnetic pulses in a system according to claim 6, characterized in that: It also includes an insulating bracket (2), which is used to insulate and fix the metal cavity (3) in the vacuum-resistant cavity (1).

8. A method for measuring the magnetic field of an electromagnetic pulse in a system, based on the magnetic field measuring device of an electromagnetic pulse in a system according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Place the metal cavity (3) in the vacuum-resistant cavity (1), ensure that the metal cavity (3) is aligned with the output port of the pulse ray source, and fix the magnetic field detector (5) at the opening position of the metal cavity (3); Step 2: placing an annular shielding lead plate (4) in the gap between the inner wall of the vacuum-resistant cavity (1) and the outer wall of the metal cavity (3) to shield and protect the magnetic field detector (5); Step 3: Use the optical fiber (6) to connect the magnetic field detector (5) and the optical fiber flange (11) of the vacuum-resistant cavity (1), and then connect the optical receiver (9) and the oscilloscope (10) in sequence; Step 4: tightly connect the pulse ray source to the flange (7) on the vacuum-resistant chamber (1); Step 5: The air in the vacuum-resistant cavity (1) is evacuated through the vacuum pipe (8) to prevent the radiation from colliding with the air to generate secondary electrons and affect the magnetic field environment; Step 6: Turn on the pulsed ray source to emit x-rays or gamma-rays; Step 7: The magnetic field probe of the magnetic field detector (5) measures the magnetic field signal in the metal cavity (3), transmits it to the optical receiver (9) through the optical fiber (6), and displays and records the measured waveform through the oscilloscope (10).

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