Flux quantum counting device and flux quantum counting method without dead zone time

Abstract

The invention provides a flux quantum counting device and a flux quantum counting method without dead zone time. Two flux lock loops respectively connected with SQUIDs of different sensitivity are reset and then the working points thereof are locked, a flux interlock unit is employed to make the other flux lock loop in a working point-locked state when one flux lock loop is reset, so that the flux change within the dead zone time from resetting to locking of the reset flux lock loop is acquired, and the working point of the reset flux lock loop after relocking can be compensated and judged. The range of the readout circuit can be extended infinitely within the normal working interval of the SQUIDs through orderly active resetting and relocking, and the linearity in the whole range is improved. Moreover, the risk of working point jump within the dead zone time for the traditional flux quantum counting method is avoided effectively, the structure design and spatial layout of the two SQUIDs of different sensitivity are optimized, and the error of measurement caused by channel crosstalk and magnetic gradient is reduced.

Description

technical field [0001] The invention relates to the technical field of superconducting electronics, in particular to a device and method for realizing magnetic flux quantum counting without dead time based on a superconducting quantum interferometer. Background technique [0002] Superconducting quantum interferometer (SQUID: SuperconductingQUantumInterferenceDevice) is a flux-voltage converter based on the Josephson structure, and it is also the most sensitive magnetic sensor known so far. There are many applications in the field of detection. [0003] In the current bias mode, the output voltage V at both ends of the SQUID changes periodically with the increase of the external magnetic flux Φ, which is the root of its huge range, but the V-Φ characteristic of the SQUID is not linear, usually It needs to be linearized through the flux lock loop (FluxLockLoop) after noise matching to achieve practical purposes, and the main working principle of FLL is to offset the change o...

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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