Gradiometer integrating pickup coils and magnetic field measurement system

A gradiometer integrated with pickup coils comprising:

• a first, a second, a third and a fourth pickup coils fabricated of a thin film on a substrate;
• a first differential SQUID fabricated of a thin film on said substrate and magnetically coupled to said first and second pickup coils, said first differential SQUID including a first and a second superconducting loop connected in series or in parallel;
• and
• a second differential SQUID fabricated of a thin film on said substrate and magnetically coupled to said third and fourth pickup coils, said second differential SQUID
• including a third and a forth superconducting loop connected in series or in parallel,
• wherein a first segment resulting from projecting a segment connecting the center of said first pickup coil with the center of said second pickup coil perpendicularly onto the surface of said substrate overlaps a second segment resulting from projecting a segment connecting the center of said first superconducting loop with the center of said second superconducting loop perpendicularly onto the surface of said substrate,
• wherein a third segment resulting from projecting a segment connecting the center of said third pickup coil with the center of said fourth pickup coil perpendicularly onto the surface of said substrate overlaps a fourth segment resulting from projecting a segment connecting the center of said third superconducting loop with the center of said fourth superconducting loop perpendicularly onto the surface of said substrate,
• wherein said first segment and said third segment cross at light angles,
• wherein a midpoint of said first segment, a midpoint of said second segment, a midpoint of said third segment, and a midpoint of said fourth segment match one another, and
• wherein said gradiometer integrated with pickup coils detects a field gradient in a z-direction with respect to an x-direction and a y-direction parallel with the surface of said substrate and perpendicular to the z-direction perpendicular to the surface of said substrate.

A gradiometer integrated with pickup coils comprising:

• a first pickup coil fabricated of a thin film on a substrate, said first pickup coil having a first and a second pickup loop connected to have an 8-figured shape as a whole such that currents flow through said first and second pickup loops in directions opposite to each other;
• a second pickup coil fabricated of a thin film on said substrate, said second pickup coil having a third and a fourth pickup loop connected to have an 8-figured shape as a whole such that currents flow through said third and fourth pickup loops in directions opposite to each other;
• a first differential SQUID fabricated of a thin film on said substrate and magnetically coupled to said first and second pickup coils, said first differential SQUID including a first and a second superconducting loop connected in series or in parallel;
• and
• a second differential SQUID fabricated of a thin film on said substrate and magnetically coupled to said third and fourth pickup coils, said second differential SQUID including a third and a forth superconducting loop connected in series or in parallel,
• wherein a first segment resulting from projecting a segment connecting the center of said first pickup loop with the center of said second pickup loop perpendicularly the surface of said substrate overlaps a second segment resulting from projecting a segment connecting the center of said first superconducting loop with the center of said second superconducting loop perpendicularly onto the surface of said substrate,
• wherein a third segment resulting from projecting a segment connecting the center of said third pickup loop with the center of said fourth pickup loop perpendicularly onto the surface of said substrate overlaps a fourth segment resulting from projecting a segment connecting the center of said third superconducting loop with the center of said fourth superconducting loop perpendicularly onto the surface of said substrate,
• wherein said first segment and said third segment cross at light angles,
• wherein a midpoint of said first segment, a midpoint of said second segment, a midpoint of said third segment, and a midpoint of said fourth segment match one another, and
• wherein said gradiometer integrated with pickup coils detects a field gradient in a z-direction with respect to an x-direction and a y-direction parallel with the surface of said substrate and perpendicular to the z-direction perpendicular to the surface of said substrate.

A gradiometer integrated with pickup coils comprising:

• a pickup coil fabricated of a thin film on a substrate, said pickup coil having a first and a second pickup loop connected to have an 8-figured shape as a whole such that currents flow through said first and second pickup loops in directions opposite to each other;
• and
• a differential SQUID fabricated of a thin film on said substrate and magnetically coupled to said first and second pickup coils, said differential SQUID including a first and
• a second superconducting loop connected in series or in parallel,
• wherein a first segment resulting from projecting a segment connecting the center of said first pickup loop with the center of said second pickup loop perpendicularly onto the surface of said substrate overlaps a second segment resulting from projecting a segment connecting the center of said first superconducting loop with the center of said second superconducting loop perpendicularly onto the surface of said substrate,
• wherein a midpoint of said first segment and a midpoint of said second segment match one another, and wherein said gradiometer integrated with pickup coils detects a field gradient in a z-direction with respect to an x-direction or a y-direction parallel with the surface of said substrate and perpendicular to the z-direction perpendicular to the surface of said substrate.

A gradiometer integrated with pickup coils comprising:

• a first and a second pickup coils each formed by a superconducting loop connected in series or in parallel;
• and
• a differential SQUID fabricated of a thin film on a substrate, said differential SQUID having a plurality of superconducting loops connected with each other and connected in parallel with said first and second pickup coils, respectively,
• wherein said first pickup coil and said second pickup coil are in parallel with the surface of said substrate, and symmetric about an x-axis or a y-axis perpendicular to a z-axis perpendicular to the surface of said substrate, and wherein said gradiometer integrated with pickup coils detects a field gradient in the z-direction with respect to the x-direction or the y-direction.

A gradiometer integrated with pickup coils comprising:

• a first and a second pickup coils each formed by a superconducting loop connected in series or in parallel;
• a first differential SQUID fabricated of a thin film on a substrate, said first differential SQUID having a plurality of superconducting loops connected with each other and connected in parallel with said first and second pickup coils, respectively;
• a third and a fourth pickup coils each formed by a superconducting loop connected in series or in parallel;
• and
• a second differential SQUID fabricated of a thin film on said substrate, said second differential SQUID having a plurality of superconducting loops connected with each other and connected in parallel with said third and fourth pickup coils, respectively,
• wherein a first segment resulting from projecting a segment connecting the center of said first pickup coil with the center of said second pickup coil perpendicularly onto the surface of said substrate and a segment connecting the center of said third pickup and the center of said fourth pickup coil perpendicularly onto the surface of said substrate cross at right angles,
• wherein a midpoint of said first segment matches a midpoint of said second segment, and
• wherein said gradiometer integrated with pickup coils detects a field gradient in a z-direction with respect to an x-direction and a y-direction parallel with the surface of said substrate and perpendicular to the z-direction perpendicular to the surface of said substrate.

A magnetic field measurement system including a gradiometer integrated with pickup coils comprising:

• a first and a second pickup coils fabricated of a thin film on a substrate;
• and a differential SQUID fabricated of a thin film on said substrate and magnetically coupled to said first and second pickup coils, said differential SQUID including a first and a second superconducting loops connected in series or in parallel,
• wherein a first segment resulting from projecting a segment connecting the center of said first pickup coil with the center of said second pickup coil perpendicularly onto the surface of said substrate overlaps a second segment resulting from projecting a segment connecting the center of said first superconducting loop with the center of said second superconducting loop perpendicularly onto the surface of said substrate,
• wherein a midpoint of said first segment matches a midpoint of said second segment, and
• wherein said gradiometer integrated with pickup coils detects a field gradient in a z-direction with respect to an x-direction or a y-direction parallel with the surface of said substrate and perpendicular to the z-direction perpendicular to the surface of said substrate.

A magnetic field measurement system including a gradiometer integrated with pickup coils comprising:

• a first, a second, a third and a fourth pickup coils fabricated of a thin film on a substrate;
• a first differential SQUID fabricated of a thin film on said substrate and magnetically coupled to said first and second pickup coils, said first differential SQUID including a first and a second superconducting loop connected in series or in parallel;
• and
• a second differential SQUID fabricated of a thin film on said substrate and magnetically coupled to said third and fourth pickup coils, said second differential SQUID
• including a third and a forth superconducting loop connected in series or in parallel,
• wherein a first segment resulting from projecting a segment connecting the center of said first pickup coil with the center of said second pickup coil perpendicularly onto the surface of said substrate overlaps a second segment resulting from projecting a segment connecting the center of said first superconducting loop with the center of said second superconducting loop perpendicularly onto the surface of said substrate,
• wherein a third segment resulting from projecting a segment connecting the center of said third pickup coil with the center of said fourth pickup coil perpendicularly onto the surface of said substrate overlaps a fourth segment resulting from projecting a segment connecting the center of said third superconducting loop with the center of said fourth superconducting loop perpendicularly onto the surface of said substrate,
• wherein said first segment and said third segment cross at light angles,
• wherein a midpoint of said first segment, a midpoint of said second segment, a midpoint of said third segment, and a midpoint of said fourth segment match one another, and
• wherein said gradiometer integrated with pickup coils detects a field gradient in a z-direction with respect to an x-direction and a y-direction parallel with the surface of said substrate and perpendicular to the z-direction perpendicular to the surface of said substrate.

A magnetic field measurement system including a gradiometer integrated with pickup coils comprising:

• a first pickup coil fabricated of a thin film on a substrate, said first pickup coil having a first and a second pickup loop connected to have an 8-figured shape as a whole such that currents flow through said first and second pickup loops in directions opposite to each other;
• a second pickup coil fabricated of a thin film on said substrate, said second pickup coil having a third and a fourth pickup loop connected to have an 8-figured shape as a whole such that currents flow through said third and fourth pickup loops in directions opposite to each other;
• a first differential SQUID fabricated of a thin film on said substrate and magnetically coupled to said first and second pickup coils, said first differential SQUID including a first and a second superconducting loop connected in series or in parallel;
• and
• a second differential SQUID fabricated of a thin film on said substrate and magnetically coupled to said third and fourth pickup coils, said second differential SQUID including a third and a forth superconducting loop connected in series or in parallel,
• wherein a first segment resulting from projecting a segment connecting the center of said first pickup loop with the center of said second pickup loop perpendicularly the surface of said substrate overlaps a second segment resulting from projecting a segment connecting the center of said first superconducting loop with the center of said second superconducting loop perpendicularly onto the surface of said substrate,
• wherein a third segment resulting from projecting a segment connecting the center of said third pickup loop with the center of said fourth pickup loop perpendicularly onto the surface of said substrate overlaps a fourth segment resulting from projecting a segment connecting the center of said third superconducting loop with the center of said fourth superconducting loop perpendicularly onto the surface of said substrate,
• wherein said first segment and said third segment cross at light angles,
• wherein a midpoint of said first segment, a midpoint of said second segment, a midpoint of said third segment, and a midpoint of said fourth segment match one another, and
• wherein said gradiometer integrated with pickup coils detects a field gradient in a z-direction with respect to an x-direction and a y-direction parallel with the surface of said substrate and perpendicular to the z-direction perpendicular to the surface of said substrate.

A magnetic field measurement system including a gradiometer integrated with pickup coils comprising:

• a pickup coil fabricated of a thin film on a substrate, said pickup coil having a first and a second pickup loop connected to have an 8-figured shape as a whole such that currents flow through said first and second pickup loops in directions opposite to each other;
• and
• a differential SQUID fabricated of a thin film on said substrate and magnetically coupled to said first and second pickup coils, said differential SQUID including a first and
• a second superconducting loop connected in series or in parallel,
• wherein a first segment resulting from projecting a segment connecting the center of said first pickup loop with the center of said second pickup loop perpendicularly onto the surface of said substrate overlaps a second segment resulting from projecting a segment connecting the center of said first superconducting loop with the center of said second superconducting loop perpendicularly onto the surface of said substrate,
• wherein a midpoint of said first segment and a midpoint of said second segment match one another, and wherein said gradiometer integrated with pickup coils detects a field gradient in a z-direction with respect to an x-direction or a y-direction parallel with the surface of said substrate and perpendicular to the z-direction perpendicular to the surface of said substrate.

A magnetic field measurement system including a gradiometer integrated with pickup coils comprising:

• a first and a second pickup coils each formed by a superconducting loop connected in series or in parallel;
• and
• a differential SQUID fabricated of a thin film on a substrate, said differential SQUID having a plurality of superconducting loops connected with each other and connected in parallel with said first and second pickup coils, respectively,
• wherein said first pickup coil and said second pickup coil are in parallel with the surface of said substrate, and symmetric about an x-axis or a y-axis perpendicular to a z-axis perpendicular to the surface of said substrate, and wherein said gradiometer integrated with pickup coils detects a field gradient in the z-direction with respect to the x-direction or the y-direction.

A magnetic field measurement system including a gradiometer integrated with pickup coils comprising:

• a first and a second pickup coils each formed by a superconducting loop connected in series or in parallel;
• a first differential SQUID fabricated of a thin film on a substrate, said first differential SQUID having a plurality of superconducting loops connected with each other and connected in parallel with said first and second pickup coils, respectively;
• a third and a fourth pickup coils each formed by a superconducting loop connected in series or in parallel;
• and
• a second differential SQUID fabricated of a thin film on said substrate, said second differential SQUID having a plurality of superconducting loops connected with each other and connected in parallel with said third and fourth pickup coils, respectively,
• wherein a first segment resulting from projecting a segment connecting the center of said first pickup coil with the center of said second pickup coil perpendicularly onto the surface of said substrate and a segment connecting the center of said third pickup and the center of said fourth pickup coil perpendicularly onto the surface of said substrate cross at right angles,
• wherein a midpoint of said first segment matches a midpoint of said second segment, and
• wherein said gradiometer integrated with pickup coils detects a field gradient in a z-direction with respect to an x-direction and a y-direction parallel with the surface of said substrate and perpendicular to the z-direction perpendicular to the surface of said substrate.