A magnetic flux quantum counting device and method without dead time

Abstract

The present invention provides a magnetic flux quantum counting device and method without dead time. After resetting two magnetic flux locking rings respectively connected to SQUIDs with different sensitivities, the working point is locked, and a magnetic flux interlocking unit is used to make the two One of the magnetic flux locking rings is in the state of the locking operating point when the reset is performed, so that the magnetic flux change of the reset magnetic flux locking ring in the dead time between reset and locking can be obtained to compensate and judge The working point after the magnetic flux locking ring of the reset is re-locked; the present invention can not only expand the range of its readout circuit infinitely in the normal working range of the SQUID by actively resetting and re-locking in an orderly manner, but also improve the linearity in the entire range In addition, it can effectively avoid the risk of operating point jump in the dead time of the traditional magnetic flux quantum counting method, optimize the structural design and spatial layout of two SQUIDs with different sensitivities, and reduce the measurement error caused by channel crosstalk and magnetic gradient.

Description

Technical field [0001] The invention relates to the technical field of superconducting electrons, in particular to a device and method for realizing time magnetic flux counting without dead zone based on a superconducting quantum interferometer. Background technique [0002] Superconducting QUantum Interference Device (SQUID: Superconducting QUantum Interference Device) is a magnetic flux-to-voltage converter based on the Josephson structure. It is also the most sensitive magnetic sensor currently known. It is used in biomagnetism, geophysics, and low-field nuclear magnetic resonance. There are many applications in the field of extremely weak magnetic field detection. [0003] In the current bias working mode, the output voltage V at both ends of the SQUID changes periodically with the increase of the external magnetic flux Φ. This is the root of its huge range, but the V-Φ characteristic of SQUID is not linear, usually After the noise is matched, it needs to be linearized by a fl...

AI Technical Summary

Problems solved by technology

Although this technology has a relatively simple circuit structure, there is a dead time when the integrator is reset. If the magnetic flux fluctuates more than one Φ0 during this dead time, the measurement data will be discontinuous and unknown, and the result The same as the problem of jumping the working point mentioned above

[0007] To sum up, the existing large-range SQUID readout circuit either has insufficient range, or has the problem of uncontrollable jumping of the working point due to the dead time, which greatly affects the application of superconducting magnetic sensors in the fields of industry, scientific research and medical treatment. wide application and promotion of

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