An actively compensated 8 nT-level magnetic shielding system for 10-m atom interferometer.
Yu-Hang Ji1, Lin Zhou1, Si-Tong Yan1
1State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan 430071, China.
The Review of Scientific Instruments
|September 2, 2021
Summary
A novel magnetic shielding system enhances atom interferometry precision. This system, using passive and active methods, significantly reduces magnetic field noise for precise weak equivalence principle tests.
Area of Science:
- Atomic physics
- Metrology
- Experimental physics
Background:
- Atom interferometers require highly stable magnetic fields for precise measurements.
- Minimizing magnetic field noise is crucial for experiments like the weak equivalence principle test.
Purpose of the Study:
- To design and develop a high-performance magnetic shielding system for a long baseline fountain-type atom interferometer.
- To achieve a magnetic field environment suitable for precision measurements at the 10^-13 level.
Main Methods:
- A combination of passive shielding using permalloy and active compensation with coils was employed.
- An 11.4 m-long, three-layer cylindrical shield was constructed and annealed.
- Active compensation techniques included external, internal, and constant magnetic field (C-field) compensation.
Main Results:
- The magnetic shielding system reduced the residual magnetic field to a maximum-to-minimum range of 8.0 nT.
- The magnetic field gradient was reduced to below 30 nT/m over 10 m along the axial direction.
- Active compensation reduced inhomogeneities to 25.0 nT, 12.6 nT, and 1.7 nT (standard deviation) sequentially.
Conclusions:
- The developed magnetic shielding system is effective for long baseline atom interferometers.
- The system is estimated to reduce systematic errors in the quadratic Zeeman shift to the 10^-13 level.
- This advancement supports high-precision weak equivalence principle tests using dual-species atom interferometry.
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