Detection of biomagnetic signals using quantum detector arrays
Inventors
De Andrade, Marcio C. • Leese de Escobar, Anna • Wiedemeier, Brandon J. • LUKOS, Jamie R. • Kasa, Shannon • Yanagi, Matthew A.
Assignees
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Publication Number
US-10338157-B2
Publication Date
2019-07-02
Expiration Date
2036-11-23
Abstract
A biosignal measuring device that can include at least one Super-conducting Quantum Interference Device (SQUID) array (SQA) of High Temperature Superconducting (HTS) Josephson Junctions (JJs). The HTS JJs operating parameters can be adjusted to establish an anti-peak response for the SQA, that can be at a maximum along a defined response axis, for detection of extremely small biomagnetic fields. For operation, the SQA can be maneuvered around a target area of a stationary subject that is emitting biomagnetic signals using a stand with three degrees of freedom, so that the response axis remains orthogonal to the subject target area. The device can further include a radome with an atomic layer deposition (ALD) window on the radome surface. The radome ALD surface can allow for passage of magnetic signals through the ALD window and radome, while simultaneously preventing passage of infrared radiation therethrough.
Core Innovation
The invention provides a biosignal measuring device featuring at least one Superconducting Quantum Interference Device (SQUID) array (SQA) composed of High Temperature Superconducting (HTS) Josephson Junctions (JJs). The operating parameters of the HTS JJs can be adjusted to establish a maximum anti-peak response along a defined response axis, enabling the detection of extremely small biomagnetic fields such as those emitted by living organisms. The device’s SQA can be maneuvered using a stand with three degrees of freedom to maintain the response axis orthogonal to the subject's target area for improved biomagnetic signal detection.
This innovation addresses the limitations of existing biomagnetic field sensors, which generally require rigid sensor placement, expensive magnetic shielded rooms, cryogenic cooling to very low temperatures, and large equipment footprints that impair portability and maneuverability. The invention overcomes these challenges by using HTS SQUID arrays that operate at higher temperatures (75-100 Kelvin) allowing for the use of liquid nitrogen cooling rather than liquid helium, thus reducing the equipment size and complexity. The shallower cooling requirements enable the device to be positioned closer to the source of biomagnetic signals, significantly enhancing sensitivity and signal strength for deeper physiological measurements.
Claims Coverage
The claims encompass multiple inventive features related to the design and operation of a biosignal measuring device utilizing HTS SQUID arrays and associated components.
Biosignal measurement device with cooler, probe housing, and vacuum system
The device comprises a cooler assembly, a probe assembly including a cold finger terminating in at least one SQUID array of HTS Josephson Junctions, enclosed by a probe housing and radome, with a vacuum valve to establish vacuum in the probe housing.
Radome with atomic layer deposition (ALD) window for selective signal passage
The radome features an ALD window allowing magnetic signals to pass through while blocking infrared radiation, conduction, and convection.
Adjustable Josephson Junction operating parameters to maximize anti-peak response
Each JJ has a set of operating parameters that are adjusted to establish a maximum anti-peak response for the SQUID array along a defined response axis.
Configurations of SQUID arrays with defined response axis orientations
The device can have one SQA with response axis perpendicular to the cold finger axis, two SQAs in a steeple configuration with response axis coinciding with the cold finger axis, or three SQAs in a pyramid configuration also aligned with the cold finger axis.
Three-degree-of-freedom swiveling stand for precise sensor orientation
In the three-SQA pyramid configuration, a swiveling stand with three degrees of freedom orients the device so that the response axis remains orthogonal to the target area of the biomagnetic signal source.
Operating temperature enabling close proximity of sensor to target area
The device operates within a temperature range allowing the radome to be positioned within 20 millimeters of the target area, facilitating detection of biomagnetic signals in the fempto-Tesla range (1-10,000 fT).
Use of YBCO material for HTS Josephson Junctions with liquid nitrogen cooling
The HTS JJs are made of YBCO material, and the cooler assembly uses liquid nitrogen as the cooling medium.
Means for maintaining HTS operating temperature and selective shielding
The device includes means to maintain HTS operating temperature between 75 and 90 degrees Kelvin and a radome to shield infrared radiation while allowing magnetic fields to pass through.
Method for biosignal measurement involving adjustment and maneuvering of SQA
A method involving providing at least one SQA of HTS JJs, adjusting their operating parameters to maximize anti-peak response, and maneuvering the SQA so that the response axis is orthogonal to the target area generating the biosignal.
Establishing vacuum and maintaining operating temperature within probe cavity
Enclosing the SQA within a probe housing and radome cavity, establishing a vacuum in the cavity, and maintaining an operating temperature between 75-90 K for optimum operation during biosignal detection.
The claims collectively cover the structural components, materials, operating parameter adjustments, configurations, cooling and vacuum systems, selective shielding windows, sensor orientation, and biosignal measurement methods using HTS SQUID arrays to achieve sensitive and portable biomagnetic signal detection.
Stated Advantages
The device can detect and analyze biomagnetic signals in unshielded environments, reducing reliance on expensive shielded rooms.
High dynamic range and broadband operation up to 100 GHz enable detection of biomagnetic signals at new frequency regimes.
Portability is improved due to relaxed cooling requirements, enabling use in diverse and real-world settings with smaller, lighter cooling apparatus.
The sensor can be placed much closer to the skin (within 20 mm) due to the higher operating temperature tolerance, increasing sensitivity to deeper brain and body signals.
The invention allows maneuvering the sensor around a stationary subject, enhancing positioning and reducing the need to move subjects.
Potential application as an active stimulation device for neuromodulation with improved spatial resolution compared to existing technologies.
Documented Applications
Non-invasive detection of biomagnetic signals from the brain, heart, spinal cord, and other biological systems.
Magnetoencephalography (MEG) for brain imaging with improved spatial and temporal resolution.
Detection of biomagnetic signals from animals, insects, and single cells or cell colonies in laboratory settings.
Potential use in non-invasive neural stimulation for neuromodulation similar to transcranial magnetic stimulation (TMS) and repetitive transcranial magnetic stimulation (rTMS).
Broadband electromagnetic radiation detection in both near and far field regions relevant to neuroscience and physiology.
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