High fidelity triangular sweep of the magnetic field for millisecond scan EPR imaging.
High fidelity triangular sweep of the magnetic field for millisecond scan EPR imaging.
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DOI：
10.1016/j.jmr.2021.107024
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发表时间：
2021-08
期刊：
影响因子：
--
通讯作者：
Zweier JL
中科院分区：
文献类型：
--
作者：
Komarov DA;Samouilov A;Hirata H;Zweier JL
磁场扫描的线性度对于高分辨率连续波EPR成像是重要的。用三角波函数驱动场是扫描EPR投影最有效的方法。然而，在快速毫秒投影扫描期间，磁场扫描轮廓可能显著失真。在这项工作中，我们介绍了一种方法来产生高度线性和适当对称的三角形扫描的磁场使用校准谐波的三角波函数。首先，得到了EPR磁体及其电源电路的频率响应函数。为此，用不同频率的正弦信号驱动场扫描线圈，并记录磁体内部的实际磁场。为了覆盖广泛的频率范围，测量是独立进行的，使用高斯计，霍尔效应线性传感器集成电路，和电感线圈。对于每个频率，确定系统增益和相位延迟。这些数据用于调整三角波函数的各个谐波的振幅和相位。校准后，对于4 ms扫描，磁场与线性函数的最大偏差为扫描宽度的0.05%。正、反向扫描的最大误差小于0.04%。改变扫描方向的扫描开销时间为5%。所提出的方法允许产生高保真度三角形磁场扫描，对于高达48 G的磁场扫描宽度和从10 s到1 ms的扫描持续时间的范围，精确度优于0.1%。
Linearity of the magnetic field sweep is important for high resolution continuous wave EPR imaging. Driving the field with triangular wave function is the most efficient way to scan EPR projections. However, the magnetic field sweep profile can be significantly distorted during fast millisecond projection scan. In this work, we introduce a method to generate highly linear and properly symmetrical triangular sweeps of the magnetic field using calibrated harmonics of the triangular wave function. First, the frequency response function of the EPR magnet and its power circuitry was obtained. For this, the field sweeping coil was driven with sinusoidal signals of different frequencies and the actual magnetic field inside the magnet was recorded. To cover wide range of frequencies, the measurements were carried out independently using gaussmeter, Hall-effect linear sensor integrated circuit, and an inductance coil. For each frequency, the system gain and the phase delay were determined. These data were used to adjust the amplitudes and the phases of individual harmonics of the triangular wave function. After the calibration, the maximum deviation of the magnetic field from the linear function was 0.05 % of sweep width for 4 ms scan. The maximum discrepancy between the forward and the reverse scan was less than 0.04 %. Sweep overhead time for changing the scan direction was 5 %. The proposed approach allows generation of high fidelity triangular magnetic field sweeps with accuracy better than 0.1 % for the range of the magnetic field sweep widths up to 48 G and scan duration from 10 s down to 1 ms.
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影响因子：
2.2
作者：
Kittell, Aaron W.;Camenisch, Theodore G.;Ratke, Joseph J.;Sidabras, Jason W.;Hyde, James S.
通讯作者：
Hyde, James S.
影响因子：
2.2
作者：
Buchanan, Laura A.;Woodcock, Lukas B.;Eaton, Gareth R.
通讯作者：
Eaton, Gareth R.
影响因子：
2.2
作者：
Czechowski, T.;Chlewicki, W.;Jurga, J.
通讯作者：
Jurga, J.
DOI：
10.1073/pnas.91.8.3388
发表时间：
1994-04-12
影响因子：
11.1
作者：
KUPPUSAMY, P;CHZHAN, M;ZWEIER, JL
通讯作者：
ZWEIER, JL
影响因子：
2.2
作者：
Joshi, JP;Ballard, JR;Eaton, GR
通讯作者：
Eaton, GR