DARPA projects aims for new magnetic gradiometers able to detect femtoTesla fields without shielding
by noreply@blogger.com (brian wang) from NextBigFuture.com on (#2GHSP)
By boosting the ability to detect superweak magnetic fields, a new DARPA program could open pathways to sensors with uses ranging from biological imaging to magnetically based navigation.
Each beat of your heart or burst of brain activity relies on tiny electrophysiological currents that generate minuscule ripples in the surrounding magnetic field. These field variations provide the basis for a range of research tools and diagnostic techniques with mouthful names like magnetoencephalography (MEG) and magnetocardiography (MCG). But tapping into biology's faint magnetic fields requires heroic and costly measures, including high-tech shields to block the larger, potentially confounding magnetic forces all around us and boutique magnetic field sensors that require expensive and cumbersome liquid helium cooling.
DARPA's new Atomic Magnetometer for Biological Imaging In Earth's Native Terrain (AMBIIENT) program is all about ushering magnetic field sensing into a new era in which MEGs, MCGs, and an assortment of other wish-list magnetic field sensing techniques become practical realities for a wide range of applications. Potentially on the horizon, for example, are sensor systems for detecting spinal signals, diagnosing concussions, and brain-machine interfaces (BMIs) for such uses as controlling prosthetic limbs and external machines via the subtle magnetic signals associated with thought.
A few elephants in the room have been preventing biomagnetic field sensing from extending beyond its current limitations. Planet Earth has been the biggest buzz kill. Its average magnetic field is 50 millionths of a Tesla, a unit of magnetic field strength named after the mid-19th and early-20th century inventor Nikola Tesla. This means that Earth's magnetic field is a million to a billion times stronger than the 10 picoTesla (10^-11 Tesla) to 10 femtoTesla (10^-14 Tesla) magnetic fields emanating from human bodies. On top of that, even today's leading-edge magnetic field sensors-based, for example, on Superconducting Quantum Interference Devices (SQUIDs)-suffer from a limited dynamic range, which means they are unable to respond reliably in the presence of magnetic field strengths that span many orders of magnitude, as is the case when biological magnetic fields superimpose upon Earth's own magnetism. Without intense shielding, those magnetic whispers from biology would be lost amidst the blaring din of Earth's magnetism, even with the best available sensors in play.
An iconic visualization of otherwise invisible magnetic field lines associated with a bar magnet hints of the far weaker biology-based magnetic fields from hearts and brains that DARPA's new AMBIIENT program aims to measure with unprecedented ease.
Read more
Each beat of your heart or burst of brain activity relies on tiny electrophysiological currents that generate minuscule ripples in the surrounding magnetic field. These field variations provide the basis for a range of research tools and diagnostic techniques with mouthful names like magnetoencephalography (MEG) and magnetocardiography (MCG). But tapping into biology's faint magnetic fields requires heroic and costly measures, including high-tech shields to block the larger, potentially confounding magnetic forces all around us and boutique magnetic field sensors that require expensive and cumbersome liquid helium cooling.
DARPA's new Atomic Magnetometer for Biological Imaging In Earth's Native Terrain (AMBIIENT) program is all about ushering magnetic field sensing into a new era in which MEGs, MCGs, and an assortment of other wish-list magnetic field sensing techniques become practical realities for a wide range of applications. Potentially on the horizon, for example, are sensor systems for detecting spinal signals, diagnosing concussions, and brain-machine interfaces (BMIs) for such uses as controlling prosthetic limbs and external machines via the subtle magnetic signals associated with thought.
A few elephants in the room have been preventing biomagnetic field sensing from extending beyond its current limitations. Planet Earth has been the biggest buzz kill. Its average magnetic field is 50 millionths of a Tesla, a unit of magnetic field strength named after the mid-19th and early-20th century inventor Nikola Tesla. This means that Earth's magnetic field is a million to a billion times stronger than the 10 picoTesla (10^-11 Tesla) to 10 femtoTesla (10^-14 Tesla) magnetic fields emanating from human bodies. On top of that, even today's leading-edge magnetic field sensors-based, for example, on Superconducting Quantum Interference Devices (SQUIDs)-suffer from a limited dynamic range, which means they are unable to respond reliably in the presence of magnetic field strengths that span many orders of magnitude, as is the case when biological magnetic fields superimpose upon Earth's own magnetism. Without intense shielding, those magnetic whispers from biology would be lost amidst the blaring din of Earth's magnetism, even with the best available sensors in play.
An iconic visualization of otherwise invisible magnetic field lines associated with a bar magnet hints of the far weaker biology-based magnetic fields from hearts and brains that DARPA's new AMBIIENT program aims to measure with unprecedented ease.Read more