SQUID System for AC Magnetic Susceptibility Measurement
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Solution Overview
Problem
Current technologies lack the sensitivity to effectively measure AC magnetic susceptibility of materials, which is crucial for characterizing magnetic properties and detecting magnetically labeled substances.
Innovation Solution
A SQUID system comprising a magnetic-flux sourcing unit, pick-up coil set, and a magnetic-flux reading unit, where the pick-up coil set senses induced magnetic flux and transfers it to a SQUID for precise measurement, allowing for improved sensitivity in detecting AC magnetization and susceptibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods are used, then the measurement setup is simple, but the sensitivity to detect AC magnetic susceptibility is insufficient
Solution Approach 1:
The patent introduces a pick-up coil as an intermediary component between the excitation coil and the SQUID. The pick-up coil converts the AC magnetic flux changes into electrical signals that can be processed by the SQUID, enabling sensitive detection of AC magnetic susceptibility while maintaining a relatively simple overall system architecture.
Solution Approach 2:
The patent replaces conventional mechanical or electronic measurement systems with a SQUID-based magnetic flux detection system. The SQUID utilizes superconducting quantum interference effects to detect magnetic flux changes with极高的 sensitivity, substituting traditional measurement mechanisms with quantum mechanical effects.
2Measurement precision
If the pick-up coil is placed close to the sample for direct sensing, then the detection sensitivity improves, but the magnetic field uniformity deteriorates
Solution Approach 1:
The patent divides the detection system into separate functional components: the excitation coil for generating the magnetic field, the pick-up coil for sensing, and the SQUID for measurement. This segmentation allows each component to be optimized independently - the pick-up coil can be positioned for optimal sensitivity while the excitation coil ensures uniform field distribution.
Solution Approach 2:
The pick-up coil acts as an intermediary that couples the excitation field to the SQUID detector. It converts magnetic flux changes into electrical signals, enabling the SQUID to detect AC magnetic susceptibility with high sensitivity while maintaining magnetic field uniformity through its intermediate positioning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The SQUID system provides significantly enhanced sensitivity in measuring AC magnetic susceptibility, enabling precise characterization of material properties and detection of magnetically labeled substances, as demonstrated by experimental results showing a clear χAC peak.
Implementation Method 1
The excitation coil set supplies a varying magnetic flux on the material
Implementation Method 2
the pick-up coil set senses an induced magnetic flux from the material
Implementation Method 3
The SQUID has the superconductive film as shown in FIG. 1A by shading. The SQUID includes two Josephson junctions 110 connected in parallel
Implementation Method 4
The SQUID 100 includes two Josephson junctions 110 connected in parallel. The electrode lead 104a is deposited on the substrate at the region 102a
Implementation Method 5
Due to the Meissener effect of superconductive material, when an external magnetic flux is shone onto a SQUID, a circulating current through these two junctions is induced to compensate the external magnetic flux within the area enclosed with the superconducting ring
Data Source
AI summary
A superconductive quantum interference device (SQUID) system is provided for measuring the alternating current (AC) magnetic susceptibility of material at a single frequency or a mixing frequency from multiple frequencies, such as mf1 + nf2, where f1 and f2 are two excitation frequencies of two primary coils. The system includes a magnetic-flux sourcing unit for producing an AC magnetic flux on a sample and a magnetic-flux reading unit for reading the induced magnetic flux from the sample via a magnetic flux transformer. The magnetic-flux reading unit includes a SQUID set for detecting the induced magnetic flux, so as to obtain the magnetic susceptibility of the sample in converting calculation.