Tracking Electromagnetic Energy
With SQUIDs
Computer Technology
Originating Technology/ NASA Contribution
A superconducting quantum interference device (SQUID)
is a gadget used to measure extremely weak signals,
specifically magnetic flux. It can detect subtle
changes in energy, up to 100 billion times weaker
than the electromagnetic energy required to move
a compass needle. SQUIDs are used for a variety
of testing procedures where extreme sensitivity
is required and where the test instrument need
not come into direct contact with the test subject.
NASA uses SQUIDs for remote, noncontact sensing
in a variety of venues, including monitoring the
Earth’s magnetic field and tracking brain activity
of pilots. Scientists at NASA’s Goddard Space Flight
Center have been making extensive use of this technology,
from astrophysical research, to tracking the navigational
paths of bees in flight to determine if they are
using internal compasses.
These very sensitive measurement devices have a
wide variety of uses within NASA and even more
uses within the commercial realm.
Partnership
|
STAR Cryoelectronics,
LLC’s line of single- and multi-channel PC-based
readout electronics for SQUIDs and SQUID amplifiers. |
STAR Cryoelectronics,
LLC (STARCryo), of Los Alamos,
New Mexico, specializes in developing, manufacturing,
and marketing ultrasensitive SQUID sensors and
advanced personal computer-based SQUID control
electronics. Its customer base is worldwide.
STARCryo was successful in obtaining NASA Phase
I and II Small Business Innovation
Research (SBIR) contract funding to develop new technologies and
bring them to market. This funding included performing
advanced electronics and sensor work at Goddard.
The work involved generating voltage gain through
arrays and cryogenic amplifiers for detectors.
Product Outcome
STARCryo’s SQUID is the most sensitive detector
of magnetic flux available, making it ideal for
a variety of uses, including high-resolution measurements
of current, voltage, magnetic field or field gradient,
gravitational field, and magnetic susceptibility.
STARCryo now offers
an extensive range of SQUID sensors and packaging
options for applications in biomedical imaging,
nondestructive testing of materials, geophysical
exploration, and basic research.
STARCryo’s SQUIDs are in use at major university,
government, and corporate research laboratories
all throughout the world.
|
The input stage
of a SQUID amplifier. |
The PC-based SQUID control-electronics that STARCryo
manufactures are marketed under the trade name
pcSQUID and offer unsurpassed flexibility and performance
for single- and multi-channel applications, in
addition to being convenient and easy to use. A
convenient interface for Microsoft Windows puts
the SQUID control on the computer, fully integrated
with data acquisition and analysis tools.
STARCryo’s sensors are used at medical research
centers around the world to record and localize
the magnetic signals associated with neural activity
in the brain. Magnetoencephalography (MEG), the
monitoring of magnetic fields in the brain, is
emerging as the primary tool for investigating
brain wave activity. Other competing techniques,
such as magnetic resonance imaging (MRI) and positron
emission tomography (PET), cannot offer the millisecond
temporal resolution attainable
with MEG.
MEG is an essential tool for mapping functional
brain activity and may be superposed with MRI data
in order to correlate localized brain activity
with anatomical information. The data are invaluable
for pre-operative surgical planning, and insurance
companies in the United States are now paying reimbursements
for the procedure.
STARCryo’s pcSQUID is also being used with magnetocardiography
(MCG), a modern medial approach to monitoring heart
health, primarily a patient’s risk of sudden cardiac
death, a disease that claims over 300,000 lives
in the United States each year. STARCryo’s ultra-sensitive
SQUID sensors are ideally suited for applications
such as MCG.
|
A process engineer
depositing thin films used to fabricate SQUID
devices. |
The SQUID sensors have also found applications
in the field of nondestructive evaluation (NDE),
where they are ideal, due to their extraordinary
sensitivity and enormous bandwidth. The NDE applications
fall into three categories: imaging of surfaces
and sub-surface features, flaws, defects, and voids
in materials; imaging of materials that have been
pre-magnetized by a pulsed or static background
magnetic field; and imaging of intrinsic or applied
electric currents in electronic circuits or materials.
In the aerospace industry, SQUIDs are being used
to obtain magnetic images of cracks in aircraft
wheel rims and to inspect jet engine turbine blades,
as well as to image defects in models of typical
aircraft lap joints. Other applications include
the evaluation of steel plates used to build ship
hulls and the inspection of concrete infrastructures,
such as bridgework.
STARCryo has also found use for their SQUIDs in
the field of geophysical exploration. Again, due
to their extreme sensitivity, small size, enormous
bandwidth, and flat frequency response, they have
been used for bore hole depth profiling, airborne
surveying, transient electromagnetics, magnetoellurics,
and controlled source
audio magnetoellurics.
pcSQUID™ is a trademark of STAR Cryoelectronics,
LLC.
Microsoft® and Windows® are registered trademarks
of Microsoft Corporation.
|