High-speed wide-range superconducting quantum interference device (SQUID) magnetic sensor and high-speed wide-range SQUID detection method

Abstract

The invention provides a high-speed wide-range superconducting quantum interference device (SQUID) magnetic sensor and a high-speed wide-range SQUID detection method. The high-speed wide-range SQUID magnetic sensor comprises a magnetic flux locking circuit for generating loop output voltage, a voltage detection circuit for detecting the loop output voltage, a controllable bias voltage circuit for regulating the bias voltage according to the loop output voltage, and a counter circuit for counting flux quantum. The method comprises steps of: outputting the loop output voltage in proportion to tested magnetic flux on the basis of the magnetic flux locking circuit; according to the state bias voltage of the loop output voltage, enabling the magnetic flux locking circuit re-locks an operating point after returning to zero; counting the hop state of the bias voltage so as to count the flux quantum; finally synthesizing the loop output voltage and a count value to achieve wide-range detection. The high-speed wide-range SQUID magnetic sensor just changes a bias voltage value rather than the transmission characteristic of an original sensor. The bias voltage value is flexibly regulated according to the response characteristics of a loop. The speed that the circuit output returns to zero is the fastest. Zero-returning control is achieved by a state switching circuit so that erroneous counting is eliminated.

Description

technical field [0001] The invention relates to the field of weak magnetic field detection, in particular to a high-speed and large-range superconducting quantum interferometer magnetic sensor and a detection method. Background technique [0002] A sensor using a superconducting quantum interference device (Superconducting Quantum Interference Device, hereinafter referred to as SQUID) is the most sensitive magnetic sensor known so far. It is widely used in the detection and scientific research of extremely weak magnetic signals such as heart magnetism, brain magnetism, and extremely low-field nuclear magnetic resonance. Due to its use of microelectronic technology, it plays an irreplaceable role in multi-channel, high-resolution, integrated high-end application systems. [0003] The SQUID device is a superconducting ring composed of two superconducting Josephson junctions connected in parallel, and the two ends of the junction are drawn out to form a passive device with two...

AI Technical Summary

Problems solved by technology

[0009] Especially in the circuit using the integrator in the flux-locked loop FLL, when resetting, the charge in the integrator capacitor must be quickly discharged to zero, so a large current is generated, which causes great damage to the reset switch and the operational discharger. The impact may easily cause circuit damage

If the discharge current is controlled, the discharge time is prolonged and the switching speed is not fast enough

[0010] 2. The switching speed of the working point of the sensor is not fast enough. The reset curve of the traditional reset circuit is an exponential decline function, so the reset time is longer as it goes to the later stage, so that missing counts or wrong counts occur.

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