Ernest Orlando Lawrence Berkeley National Laboratory
| APPLICATIONS OF TECHNOLOGY:
- Eliminates excess low-frequency noise inherent in SQUID devices
ABSTRACT: John Clarke and colleagues at Berkeley Lab have eliminated excess low frequency noise in high-transition temperature (Tc) superconducting quantum interference devices (SQUIDs) and SQUID-based magnetometers operating in ambient magnetic fields. Using SQUIDs fabricated with precise slots and holes, researchers have reduced the problem of intrinsic magnetic noise, previously a major impediment to the application of high-Tc SQUIDs in the earth's magnetic field, to an artifact of design. This new innovation improves operation of both single-layer and superconducting multilayer SQUID devices, with the low noise, multilayer magnetometer offering the highest sensitivity for a given size. This invention is an essential ingredient for operation of SQUID-based devices in medical applications, such as magnetocardiography and magnetoencephalography. It obviates the need for expensive, magnetically shielded rooms. Other applications include geophysical studies, for example, magnetotellurics (MT) and controlled-source electromagnetics (CSEM), in which it is essential to operate the magnetometers in an unshielded environment.
STATUS: U.S. Patent #6,023,161. Available for licensing
FOR MORE INFORMATION PLEASE SEE:
- Dantsker E.,Tanaka S., Nilsson PA, Kleiner R., Clarke J., "Reduction of 1/f noise in high-Tc dc superconducting quantum interference devices cooled in an ambient magnetic field," Applied Physics Letters, 1996, 69, 4099.
- Dantsker E., Tanaka S., Clarke J., "High-Tc super conducting quantum interference devices with slots or holes: Low 1/f noise in ambient magnetic fields," Applied Physics Letters, 1997, 70, 2037.
- Dantsker E.,Tanaka S., Nilsson PA, Kleiner R., Clarke J., "Low Excess Flux Noise in YBa2Cu3O7-x dc SQUIDs Cooled in Static Magnetic Fields," IEEE, Applied Superconductivity, Vol. 7, No. 2, June 1997
REFERENCE NUMBER: IB-1221
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