Cross-Axis projection error in optically pumped magnetometers and its implication for magnetoencephalography systems.
Cross-Axis projection error in optically pumped magnetometers and its implication for magnetoencephalography systems.
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DOI：
10.1016/j.neuroimage.2021.118818
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发表时间：
2022-02-15
期刊：
影响因子：
5.7
通讯作者：
Schwindt PDD
中科院分区：
文献类型：
--
作者：
Borna A;Iivanainen J;Carter TR;McKay J;Taulu S;Stephen J;Schwindt PDD
为脑磁图（MEG）开发的光泵磁力计（OPM）通常在无自旋交换弛豫（SERF）机制下工作，并测量垂直于光泵光子传播轴的磁场分量。用于MEG的最常见类型的OPM采用碱金属原子（例如，87 Rb）作为感测元件，并且采用一个或多个激光器用于制备和询问碱金属原子系综的磁敏感状态。在SERF区，碱金属原子的自旋交换速率比拉莫尔旋进频率快得多，因而可以大大提高OPM的灵敏度。SERF机制可容纳高达±5 nT的剩余静磁场。然而，在所提出的工作中，通过仿真和实验，我们证明，在存在小的剩余静磁场的多轴磁信号，不违反SERF标准，可以引入显着的误差项在OPM的输出信号。我们将这些确定性误差称为交叉轴投影误差（CAPE），其中MEG信号的垂直于标称感测轴的磁场分量对OPM信号有贡献，从而引起实质性的幅度和相位误差。此外，通过仿真，我们已经发现，CAPE会降低定位和校准精度的基于OPM的脑磁图（OPM-MEG）系统。
Optically pumped magnetometers (OPMs) developed for magnetoencephalography (MEG) typically operate in the spin-exchange-relaxation-free (SERF) regime and measure a magnetic field component perpendicular to the propagation axis of the optical-pumping photons. The most common type of OPM for MEG employs alkali atoms, e.g. 87 Rb, as the sensing element and one or more lasers for preparation and interrogation of the magnetically sensitive states of the alkali atoms ensemble. The sensitivity of the OPM can be greatly enhanced by operating it in the SERF regime, where the alkali atoms’ spin exchange rate is much faster than the Larmor precession frequency. The SERF regime accommodates remnant static magnetic fields up to ±5 nT. However, in the presented work, through simulation and experiment, we demonstrate that multi-axis magnetic signals in the presence of small remnant static magnetic fields, not violating the SERF criteria, can introduce significant error terms in OPM’s output signal. We call these deterministic errors cross-axis projection errors (CAPE), where magnetic field components of the MEG signal perpendicular to the nominal sensing axis contribute to the OPM signal giving rise to substantial amplitude and phase errors. Furthermore, through simulation, we have discovered that CAPE can degrade localization and calibration accuracy of OPM-based magnetoencephalography (OPM-MEG) systems.
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影响因子：
4
作者：
Seltzer, SJ;Romalis, MV
通讯作者：
Romalis, MV
在头皮安装的磁刻摄影术中用于无效背景磁场的双平面线圈系统。
影响因子：
5.7
作者：
Holmes N;Leggett J;Boto E;Roberts G;Hill RM;Tierney TM;Shah V;Barnes GR;Brookes MJ;Bowtell R
通讯作者：
Bowtell R
影响因子：
3.7
作者：
Boto E;Bowtell R;Krüger P;Fromhold TM;Morris PG;Meyer SS;Barnes GR;Brookes MJ
通讯作者：
Brookes MJ
影响因子：
5.7
作者：
Iivanainen J;Stenroos M;Parkkonen L
通讯作者：
Parkkonen L
影响因子：
64.8
作者：
Kominis, IK;Kornack, TW;Romalis, MV
通讯作者：
Romalis, MV