A hierarchical shunt locking magnetic field stabilization system with ultra-low magnetic field noise

Abstract

The invention discloses a graded shunt locking magnetic field stabilization system with ultra-low magnetic field noise, which suppresses magnetic field specific direction noise in a space volume through non-contact detection and graded shunt. Based on the influence of coil current noise on the magnetic field in the space volume, the first-stage feedback shunt locking loop is designed to stabilize the low-frequency current noise on the coil and most of the current noise at 50Hz and its harmonics, and stabilize the current noise to 10% of the output current. ‑5 ;Based on the contribution of ambient magnetic field noise to the magnetic field noise in the space volume, a second-stage feedback shunt locking loop is designed, and a magnetic field detector is used to indirectly detect the noise in a specific direction of the space volume magnetic field, and a current disturbance in antiphase to the magnetic field noise is added to the coil current, Offset the environmental magnetic field noise, suppress the magnetic field noise in the space volume to tens of microgauss, and achieve ultra-low magnetic field noise. The system improves the precision of magnetic field locking; by adjusting parameters, it can be adapted to different combinations of current sources and Helmholtz coils, and applied to different magnetic field environments.

Description

technical field [0001] The invention relates to the field of magnetic field detection, in particular to a hierarchical shunt locking magnetic field stabilization system with ultra-low magnetic field noise. Background technique [0002] Ultra-low magnetic field noise is of great significance to many frontier scientific researches. For example, measurements of atomic interference, microgravity, electron microscopy, nuclear magnetic resonance, magnetic ranging and atomic clock experiments all benefit from advances in magnetic field stabilization. [0003] The noise of the magnetic field mainly comes from the current fluctuation of the coil that generates the magnetic field and the magnetic field noise introduced by the surrounding environment. Among them, the current fluctuation of the coil mainly comes from the noise output by the power supply supplying the coil itself and the resonance effect generated by the coupling between the power supply and the coil; while the magnetic...

AI Technical Summary

Problems solved by technology

[0004] In order to obtain a stable magnetic field, we can start with the source of magnetic field noise. On the one hand, we can directly switch to a low-noise current source, but the output current fluctuation of most current sources is one thousandth, or even one percent, and some A power supply whose ripple noise can reach one hundred thousandth of the output current, but its price is high and it is difficult to popularize

However, low current ripple noise does not mean low magnetic field noise. It is also necessary to consider the magnetic field noise introduced in the environment. Magnetic shielding is usually used to reduce the noise of stray magnetic fields in the environment. Some structural designs, it is usually difficult to shield the entire system

And if what needs to be stabilized is a magnetic field with a size of tens to hundreds of gauss, it is easy to make the magnetic shielding box reach magnetic saturation, thus affecting the magnetic field shielding effect, and its structure is often limited by the design of existing experimental devices

Images