Magnetic field shielding system based on closed superconducting coil groups and magnetic field shielding device

Patent metadata

Field	Value
Publication number	US-10015917-B2
Application number	US-201615005021-A
Country	US
Kind code	B2
Filing date	Jan 25, 2016
Priority date	Jul 26, 2013
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

A magnetic field shielding system includes a first stage superconducting coil and a second stage superconducting coil. The first stage superconducting coil and the second stage superconducting coil are coaxial, coplanar and electrically connected in series to form a closed loop; the first stage superconducting coil has a first radius R1, the second stage superconducting coil has a second radius R2, and R1>R2; a radius ratio α between the first radius R1 and the second radius R2 is: α=R1/R2; the first stage superconducting coil has N1 turns; the second stage superconducting coil has N2 turns; a turns ratio β between N1 and N2 is: β=N1/N2; and the radius ratio α satisfies: α≥2; the turns ratio β satisfies: 0.01≤β≤20.

First claim

What is claimed is:

1. A magnetic field shielding system comprising:
a first stage superconducting coil and a second stage superconducting coil;
wherein the first stage superconducting coil and the second stage superconducting coil are coaxial, coplanar and electrically connected in series to form a closed loop; the first stage superconducting coil has a first radius R1, the second stage superconducting coil has a second radius R2, and R1>R2; a radius ratio α between the first radius R1 and the second radius R2 is: α=R1/R2; the first stage superconducting coil has N1 turns; the second stage superconducting coil has N2 turns; a turns ratio β between N1 and N2 is: β=N1/N2; and the radius ratio α satisfies: α≥2; the turns ratio β satisfies: 0.01β≤20.

2. The magnetic field shielding system of claim 1 , wherein the first stage superconducting coil and the second stage superconducting coil are concentric.

3. The magnetic field shielding system of claim 1 , wherein each of the first stage superconducting coil and the second stage superconducting coil is formed by a single superconducting wire spiral wounded around a central symmetry axis.

4. The magnetic field shielding system of claim 1 , wherein the first stage superconducting coil comprises a first end and a second end, the second stage superconducting coil comprises a third end and a fourth end, the first end is connected to the third end, and the second end is connected to the fourth end to form the closed loop.

5. The magnetic field shielding system of claim 1 , wherein the turns N2 of the second stage superconducting coil satisfies:

N
⁢

⁢
2

>

m
⁢

⁢
R

L
⁢

⁢
ω

;

wherein, R is a connecting resistance between the first stage superconducting coil and the second stage superconducting coil; L is an inductance of a single-turn coil of the second stage superconducting coil, ω is an angular frequency of a magnetic field, and m is a ratio coefficient between ωL and R.

6. The magnetic field shielding system of claim 1 , wherein one of the first stage superconducting coil and the second stage superconducting coil comprises a plurality of pancake-shaped coils, and another one of the first stage superconducting coil and the second stage superconducting coil comprises a plurality of solenoid-shaped coils.

7. A magnetic field shielding system comprising:
a first coil group and a second coil group;
wherein the first coil group and the second coil group are spaced and insulated from each other; the first coil group and the second coil group are coaxial; each of the first coil group and the second group comprises a first stage superconducting coil and a second stage superconducting coil; and the first stage superconducting coil and the second stage superconducting coil are coaxial and electrically connected in series to form a closed loop; the first stage superconducting coil and the second stage superconducting coil are coplanar.

8. The magnetic field shielding system of claim 7 , wherein the first stage superconducting coil and the second stage superconducting coil are spaced from each other.

9. The magnetic field shielding system of claim 7 , wherein a first size of the first stage superconducting coil is greater than a second size of the second stage superconducting coil, and the second stage superconducting coil is located inside the first stage superconducting coil.

10. The magnetic field shielding system of claim 7 , further comprises a third stage superconducting coil located at the middle between the first coil group and the second coil group.

11. The magnetic field shielding system of claim 10 , wherein the third stage superconducting coil is spaced and insulated from the first coil group and the second coil group; the first stage superconducting coil, the second stage superconducting coil, and the third stage superconducting coil are coaxial and parallel with each other.

12. The magnetic field shielding system of claim 10 , wherein the first coil group and the second coil group are symmetric with each other respect to the third stage superconducting coil.

13. The magnetic field shielding system of claim 10 , wherein the third stage superconducting coil is electrically connected in series between the first coil group and the second coil group.

14. A magnetic field shielding device comprising:
a dewar, wherein the dewar is a hollow structure comprising an inner wall and an outer wall spaced from each other, and the inner wall and the outer wall are located around the same central symmetry axis;
a magnetic field shielding system accommodated in the dewar, wherein the magnetic field shielding system comprises a first coil group comprising a first stage superconducting coil and a second stage superconducting coil coaxially located around the central symmetry axis, the first stage superconducting coil and the second stage superconducting coil are located between the inner wall and the outer wall; and
an adjustment module connected to the magnetic field shielding system, wherein the adjustment module comprises a first connecting rod and a second connecting rod configured to adjust a relative position between the first stage superconducting coil and the second stage superconducting coil, the first connecting rod is connected to the first stage superconducting coil, and the second connecting rod is connected to the second stage superconducting coil.

15. The magnetic field shielding device of claim 14 , wherein the first stage superconducting coil and the second stage superconducting coil are coplanar and spaced from each other.

16. The magnetic field shielding device of claim 14 , further comprising a ferromagnetic dielectric ring coaxially located with the first stage superconducting coil and the second stage superconducting coil, wherein the ferromagnetic dielectric ring is spaced from the first stage superconducting coil and the second stage superconducting coil, and the ferromagnetic dielectric ring defines a notch.

17. The magnetic field shielding device of claim 14 , further comprising a closed superconducting loop coaxially located with the first stage superconducting coil and the second stage superconducting coil, wherein the closed superconducting loop is spaced from the first stage superconducting coil and the second stage superconducting coil.

18. The magnetic field shielding device of claim 14 , further comprising a second coil group spaced and insulated from the first coil group, wherein the second coil group comprises a third superconducting coil and a fourth stage superconducting coil coaxially located the central symmetry axis and parallel with each other; the third stage superconducting coil is the same as the first superconducting coil, and the fourth stage superconducting coil is the

Assignees

• Univ Tsinghua

Inventors

• Gu Chen
• Chen si-wei
• Qu Ti-Ming
• Han Zheng-He

Classifications

• H05K9/0052

  Shielding other than Faraday cages · CPC title

• H05K9/0077 Primary

  comprising superconductors · CPC title