High-sensitivity magnetic measurement device in environment field based on disturbance compensation and realization method thereof

Abstract

The invention discloses a high-sensitivity magnetic measurement device in an environment field based on disturbance compensation and a realization method thereof. In the method, the low-frequency disturbance compensation in an environment magnetic field is realized by a second feedback branch and a second magnetic flux locking loop, wherein the second feedback branch is composed of a second integrator, a low-pass filter, a second feedback resistor and a feedback coil; and the second magnetic flux locking loop is formed based on the second feedback branch. A super-magnetic conduction sensor established based on the method can realize the high-pass response frequency characteristics for the environment field and the low-pass response frequency characteristics for the circuit noise at the same time, ensures the suppression of the influence of environment field disturbance on SQUID (superconducting quantum interference device) magnetic measurement without influencing the weak signal measurement, and avoids the overflow phenomenon. Based on the super-magnetic conduction sensor, the method is suitable for the application environment in which the frequency of the magnetic field signal tobe measured is higher than the disturbance frequency band (DC-30Hz) of the environment field.

Description

technical field [0001] The present invention relates to a high-sensitivity magnetic measurement device under an environmental field based on disturbance compensation and an implementation method, more precisely, it provides a high-sensitivity magnetic measurement implementation method under an environmental field based on a superconducting magnetic sensor (SQUID-superconducting quantum interference device) , especially the second feedback branch with low-pass characteristics. Background technique [0002] Superconducting magnetic sensor SQUID (sensitivity up to 10 -15 T) can be used to measure weak magnetic field signals, but the low-frequency disturbance of the environmental field (frequency below 30Hz, up to 10 -6 T level) will make the dynamic range of the superconducting magnetic sensor face a huge challenge (above 140dB), which exceeds the limit of the dynamic range that can be achieved by general technical means. In order to give full play to the high sensitivity adv...

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Problems solved by technology

[0006] The active compensation method provided above can be applied to the field where the magnetic signal source is far away from the superconducting magnetic sensor, but the compensation device occupies a large space and is inconvenient to move; at the same time, the feedback circuit will also introduce circuit noise, which is easy to send to the magnetic sensor through the feedback coil. Feedback noise, which leads to a decrease in magnetic measurement sensitivity,

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