Rapid-scan EPR imaging.
Rapid-scan EPR imaging.
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DOI：
10.1016/j.jmr.2017.02.013
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发表时间：
2017-07
期刊：
影响因子：
--
通讯作者：
Eaton GR
中科院分区：
文献类型：
--
作者：
Eaton SS;Shi Y;Woodcock L;Buchanan LA;McPeak J;Quine RW;Rinard GA;Epel B;Halpern HJ;Eaton GR
在快速扫描EPR中，磁场或频率以比常规连续波EPR快得多的速率重复扫描通过频谱。该信号在源频率处由混频器直接检测。当通过共振的扫描速率相对于电子自旋弛豫速率快时，快速扫描EPR特别有利。在这样的扫描中，在光谱的后沿上可能存在振荡。这些振荡可以通过数学去卷积来消除，以恢复慢扫描吸收光谱。在不均匀加宽的情况下，振荡可能会产生破坏性干扰，以至于不可见。即使在不需要时也可以使用去卷积，因此可以获得其中光谱的一些部分处于快速扫描状态而一些部分不处于快速扫描状态的光谱。只要能在线性响应区获得谱，快速扫描EPR技术就可以普遍应用。在每次扫描中的全光谱的检测，使用更高的微波功率而不饱和的能力，以及相干平均中固有的噪声滤波导致相对于常规连续波光谱学的信噪比的实质性改善，这对于低频EPR成像是特别有利的。本概述介绍了快速扫描EPR的原理和用于产生光谱的硬件。提供了其应用程序的氮氧自由基，双自由基，和自旋捕获自由基在拉莫尔频率约成像的例子。250兆赫。
In rapid-scan EPR the magnetic field or frequency is repeatedly scanned through the spectrum at rates that are much faster than in conventional continuous wave EPR. The signal is directly-detected with a mixer at the source frequency. Rapid-scan EPR is particularly advantageous when the scan rate through resonance is fast relative to electron spin relaxation rates. In such scans, there may be oscillations on the trailing edge of the spectrum. These oscillations can be removed by mathematical deconvolution to recover the slow-scan absorption spectrum. In cases of inhomogeneous broadening, the oscillations may interfere destructively to the extent that they are not visible. The deconvolution can be used even when it is not required, so spectra can be obtained in which some portions of the spectrum are in the rapid-scan regime and some are not. The technology developed for rapid-scan EPR can be applied generally so long as spectra are obtained in the linear response region. The detection of the full spectrum in each scan, the ability to use higher microwave power without saturation, and the noise filtering inherent in coherent averaging results in substantial improvement in signal-to-noise relative to conventional continuous wave spectroscopy, which is particularly advantageous for low-frequency EPR imaging. This overview describes the principles of rapid-scan EPR and the hardware used to generate the spectra. Examples are provided of its application to imaging of nitroxide radicals, diradicals, and spin-trapped radicals at a Larmor frequency of ca. 250 MHz.
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影响因子：
2.2
作者：
Kittell, Aaron W.;Hustedt, Eric J.;Hyde, James S.
通讯作者：
Hyde, James S.
DOI：
10.1016/j.jmr.2010.04.005
发表时间：
2010-07
期刊：
Journal of magnetic resonance (San Diego, Calif. : 1997)
影响因子：
--
作者：
Hyde JS;Strangeway RA;Camenisch TG;Ratke JJ;Froncisz W
通讯作者：
Froncisz W
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：
15
作者：
FINKELSTEIN, E;ROSEN, GM;RAUCKMAN, EJ
通讯作者：
RAUCKMAN, EJ
影响因子：
2.2
作者：
Czechowski, T.;Chlewicki, W.;Jurga, J.
通讯作者：
Jurga, J.