Detection of undistorted continuous wave (CW) electron paramagnetic resonance (EPR) spectra with non-adiabatic rapid sweep (NARS) of the magnetic field.
Detection of undistorted continuous wave (CW) electron paramagnetic resonance (EPR) spectra with non-adiabatic rapid sweep (NARS) of the magnetic field.
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DOI：
10.1016/j.jmr.2011.06.004
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发表时间：
2011-08
影响因子：
2.2
通讯作者：
Hyde, James S.
中科院分区：
文献类型：
--
作者：
Kittell, Aaron W.;Camenisch, Theodore G.;Ratke, Joseph J.;Sidabras, Jason W.;Hyde, James S.
关键词：
连续波（CW）电子顺磁共振（EPR）谱通常显示为对100 kHz磁场调制的应用的第一谐波响应，其用于通过降低1/f噪声水平来增强灵敏度。然而，任何幅度的磁场调制都会导致光谱展宽，并以至少两倍的因子牺牲EPR光谱强度。在这里提出的工作中，CW快速扫描光谱技术，避免这些妥协，也提供了一种避免1/f噪声的方法。这种技术，称为非绝热快速扫描（NARS）EPR，包括重复扫描的极化磁场在一个频谱片段的线性方式与一个小线圈在重复率是足够高的接收器噪声，微波相位噪声，和环境的颤噪，其中每一个都有1/f特性，被克服。然而，扫描的速率足够慢，从而避免绝热响应，并且自旋系统总是接近热平衡。对来自光谱片段的重复采集的光谱进行平均。在这些条件下，获得了无失真的纯吸收光谱，而没有信号强度的加宽或损失。应用诸如移动平均的数字滤波器来去除高频噪声，其在带宽上近似等于在具有锁定检测的常规场调制中使用积分时间常数。给出了氮氧自由基在L-和X-波段的光谱。
A continuous wave (CW) electron paramagnetic resonance (EPR) spectrum is typically displayed as the first harmonic response to the application of 100 kHz magnetic field modulation, which is used to enhance sensitivity by reducing the level of 1/f noise. However, magnetic field modulation of any amplitude causes spectral broadening and sacrifices EPR spectral intensity by at least a factor of two. In the work presented here, a CW rapid-scan spectroscopic technique that avoids these compromises and also provides a means of avoiding 1/f noise is developed. This technique, termed non-adiabatic rapid sweep (NARS) EPR, consists of repetitively sweeping the polarizing magnetic field in a linear manner over a spectral fragment with a small coil at a repetition rate that is sufficiently high that receiver noise, microwave phase noise, and environmental microphonics, each of which has 1/f characteristics, are overcome. Nevertheless, the rate of sweep is sufficiently slow that adiabatic responses are avoided and the spin system is always close to thermal equilibrium. The repetitively acquired spectra from the spectral fragment are averaged. Under these conditions, undistorted pure absorption spectra are obtained without broadening or loss of signal intensity. A digital filter such as a moving average is applied to remove high frequency noise, which is approximately equivalent in bandwidth to use of an integrating time constant in conventional field modulation with lock-in detection. Nitroxide spectra at L- and X-band are presented.
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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
DOI：
10.1098/rspa.1966.0138
发表时间：
1966-01-01
影响因子：
--
作者：
BARLOW, AJ;LAMB, J;MATHESON, AJ
通讯作者：
MATHESON, AJ
影响因子：
1
作者：
Hyde, J. S.;Pasenkiewicz-Gierula, M.;Antholine, W. E.
通讯作者：
Antholine, W. E.
影响因子：
2.2
作者：
Bales, BL;Peric, M;Lamy-Freund, MT
通讯作者：
Lamy-Freund, MT
DOI：
10.1109/tmtt.1983.1131661
发表时间：
1983-01-01
影响因子：
4.3
作者：
MEHDIZADEH, M;ISHII, TK;FRONCISZ, W
通讯作者：
FRONCISZ, W