Superconducting Loop Constriction Magnetic Field Sensor
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Solution Overview
Problem
Conventional magnetic field sensors, such as SQUIDs and Optically Pumped Magnetometers, face limitations in sensitivity, robustness to external fields, and integration with other imaging modalities like High Field MRI or Transcranial Magnetic Stimulation, due to noise floors and requirements for cooling and calibration.
Innovation Solution
A hybrid sensor device featuring a closed superconducting loop with a constriction to amplify and shape the magnetic field, coupled with a vibrating mechanical oscillator and an optical detector to monitor resonance frequency changes, enhancing sensitivity and robustness to external fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If SQUIDs are used for magnetic field sensing, then sensitivity is improved (1 fT/sqrt(Hz)), but the device requires liquid helium cooling and is not robust to strong external fields
Solution Approach 1:
The patent changes the operating temperature parameter from cryogenic (liquid helium at 4.2K) to elevated temperature (liquid nitrogen at 77K or higher) by using high-temperature superconducting materials, thereby simplifying the cooling system while maintaining superconducting properties for magnetic field sensing
Solution Approach 2:
The patent introduces a magnetic shield as an intermediary component between the SQUID sensor and external magnetic fields. This shield blocks strong external magnetic fields from reaching the sensitive sensor, enabling the device to operate in environments with strong external fields such as MRI scanners and TMS devices
2Temperature
If HTS materials are used for SQUIDs, then operating temperature is improved (77K), but noise increases and reproducibility decreases
Solution Approach 1:
The patent replaces the conventional SQUID detection mechanism with a mechanical oscillator-based detection system. A magnetic field-sensitive mechanical oscillator is coupled to the superconducting loop, and its resonance frequency is modulated by the magnetic field. This mechanical detection approach reduces noise and improves reproducibility compared to traditional electrical detection methods in HTS SQUIDs
3Measurement precision
If SQUIDs are used for magnetic field sensing, then sensitivity is improved, but robustness to external fields deteriorates (limit of 150 mT)
Solution Approach 1:
The patent introduces a magnetic shield as an intermediary component between the SQUID sensor and external magnetic fields. This shield blocks strong external magnetic fields from reaching the sensitive sensor, enabling the device to operate in environments with strong external fields such as MRI scanners and TMS devices
4Measurement precision
If conventional magnetic field sensors are used, then sensitivity is improved, but integration with other imaging modalities deteriorates
Solution Approach 1:
The patent introduces a magnetic shield as an intermediary component between the SQUID sensor and external magnetic fields. This shield blocks strong external magnetic fields from reaching the sensitive sensor, enabling the device to operate in environments with strong external fields such as MRI scanners and TMS devices
Solution Approach 2:
The patent designs a hybrid sensor system that can operate in multiple imaging modalities (MEG, MRI, TMS) simultaneously. The magnetic shield enables the sensor to tolerate external fields from MRI and TMS, while the mechanical oscillator detection method maintains sensitivity for biomagnetic field detection, achieving multi-functional capability
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 hybrid sensor achieves a detection limit of 10 fT/sqrt(Hz) and is robust to static and pulsed external fields, enabling multimodal imaging and simultaneous operation of multiple channels without cross-talk, facilitating integration with other techniques like MRI.
Implementation Method 1
a closed superconducting loop configured to collect a magnetic field to be sensed, hereinafter external magnetic field
Implementation Method 2
said constriction generating an amplified and non-uniform local magnetic field, hereinafter internal magnetic field, in response to said external magnetic field
Implementation Method 3
a vibrating mechanical oscillator coupled to, or formed by said constriction and responsive to the internal magnetic field, and a detector configured to detect deflection or vibration of said mechanical oscillator
Data Source
Figure 1(a)~2(e)
Figure 3a~3b
Figure 4a~4b
AI summary
A device for sensing a magnetic field, comprising a closed superconducting loop (10) configured to collect a magnetic field to be sensed, hereinafter external magnetic field, the closed superconducting loop having a path width (wp) and being provided with a constriction (11) having a width (wc) narrower than the path width, the constriction generating a non-uniform magnetic field, hereinafter internal magnetic field, in response to the external magnetic field, a vibrating mechanical oscillator (20) coupled to, or formed by the constriction and responsive to the internal magnetic field, and a detector (60, 90, 100) configured to detect deflection or vibration of the mechanical oscillator and providing a signal indicative of the deflection or vibration.