Precision measurement of laser RF double resonance spectra with an effective compensation of residual magnetic field

2013 ◽  
Vol 227 (1-3) ◽  
pp. 147-156 ◽  
Author(s):  
X. F Yang ◽  
◽  
T. Furukawa ◽  
T. Fujita ◽  
K. Imamura ◽  
...  
2022 ◽  
Vol 2160 (1) ◽  
pp. 012033
Author(s):  
Xiaoxuan Xie ◽  
Xiangyang Zhou

Abstract The ultra-high-precision measurement of the atomic magnetometer is largely restricted by the size of its working magnetic field. In order to reduce the residual magnetic field as much as possible, this article carried out the research on the methods to improve the shielding performance. Firstly, the axial shielding factor that limits the shielding performance of the magnetic shielding barrel was derived with various parameters including the radius, length, thickness, number of layers, distance between adjacent layers, etc. of the magnetic shielding barrel. Secondly, simulation was carried out to verify the correctness of the formula. Simulation shows that the shielding performance of the magnetic shielding barrel decreases with the size of magnetic shielding barrel increase. Besides, with the increase of the distance between two adjacent spacing layers, the shielding performance first increases rapidly and then gradually decreases, indicating that the optimal distance between adjacent layers is 9mm. Especially, the performance of the magnetic shielding barrel improves significantly as the layer thickness and number of layers increase. Experimental results show that the internal remanence of the three-layer magnetic shielding barrel is less than 1nT, and the available axial length of homogeneity range is greater than 200mm.


The L3 experiment has completed the first two years of data-taking at the LEP e + e - collider at CERN. The detectors are contained in a very large solenoidal magnetic field volume, with the emphasis on precision measurement of electrons, photons and muons. The physics goals, design and performance of the detector are reviewed, with highlights from the results that have been obtained during LEP running at the Z 0 resonance.


2020 ◽  
Vol 10 (11) ◽  
pp. 3745
Author(s):  
Yiqiu Tan ◽  
Danfeng Zhou ◽  
Mengxiao Song ◽  
Jie Li

Residual magnetic interference induced by applied magnetic field pulses inside a conductive shielded room (SR) has been a common issue in ultra-low-field (ULF) nuclear magnetic resonance (NMR). The rapid cutoff of the applied pre-polarizing field (Bp) induces eddy currents in the walls of the SR, which produces a decaying residual magnetic interference that may cause severe image distortions and signal loss. In this study, a pair of cancellation coils (CC) and control electronics were designed for the suppression of the residual magnetic interference in a SR. Simulations show that this method was effective in suppressing the residual magnetic field (Br) after removal of the pre-polarizing magnetic field. Then, a small-scale SR was designed and the effectiveness of this cancellation scheme was experimentally verified. The test results showed a good agreement with the simulation, which indicated that the cancellation scheme was capable of reducing Br field to a much lower level. The scheme proposed in this study provides a solution for suppressing the residual magnetic field in the ULF NMR system. After decoupling the eddy–current field, the effect of the suppression may be further improved by optimization of the cancellation coil in further work.


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