• journal_title：The Leading Edge
• Contributor：K. E. Leslie ; R. A. Binks ; S. K. H. Lam ; P. A. Sullivan ; D. L. Tilbrook ; R. G. Thorn ; C. P. Foley
• Publisher：Society of Exploration Geophysicists
• Date：2008-
• Format：text/html
• Language：en
• Identifier：10.1190/1.2831682
• journal_abbrev：The Leading Edge
• issn：1070-485X
• volume：27
• issue：1
• firstpage：70
• section：Special section: Mining Geophysics

Superconducting quantum interference devices (SQUIDs) are intrinsically very sensitive detectors of magnetic flux. Flux sensitivities of one millionth of a flux quantum per root Hz (1μϕ₀/√Hz) may typically be realized in low-temperature superconductor (LTS) materials, while sensitivities of ∼5μϕ₀/√Hz may be realized in high-temperature superconductor (HTS) materials. LTS devices are typically cooled with liquid helium (4 K) while HTS devices are typically cooled with liquid nitrogen (77 K). Coupling the magnetic field into a SQUID via a flux-transformer can result in a very sensitive magnetometer with, depending on the type of superconducting material used and the effective area of the flux-coupling transformer, achievable magnetic field sensitivities ranging from fT/√Hz to pT/√Hz over typical bandwidths that span hundreds of kHz. SQUID applications include NDE, biomagnetism and magnetic microscopes.