INNOVATIVE RESONATOR FOR BIOMEDICAL EPR SPECTROSCOPY

描述：研制了一种用于电子顺磁共振波谱的新型谐振器 由创新科技基金(RR09882)资助。交叉环路 谐振器(CLR)由两个几乎独立的集总元件组成 谐振器具有共同的采样体积，其中两个环路 谐振器垂直相交。第一个谐振器激发自旋，并且 第二谐振器只检测由自旋系统引起的信号。这个 信号源的相位噪声被反射回信号源，并有效地 与EPR信号隔离(70分贝)。CLR消除了对 常规光谱仪中用于引导EPR的微波环行器 信号传给探测器。CLR基本上消除了源阶段 检测信号中的噪声，提高分光计灵敏度，并允许 在与高信噪比(S/N)相同的情况下测量的色散谱 吸收光谱。因为信号的基线与 CLR，磁场调制可以用超外差代替 检测，不会导致信号失真(通道效应) 与场调制一起发生。对于脉冲实验，CLR大大 减少仪器的停滞时间，并允许测量部分 之前无法访问的信号。取消环行器可以 在样品附近放置一个低噪声放大器，并与样品一起冷却， 大大增加了S/N。现在建议在#年进一步发展CLR。 生物电子顺磁共振测量的三个主要方法 样品，特别是在低温下：1)表明 超外差检测将提供失真更小的信号和更高的 信噪比(S/N)比场调制，2)说明消除了 环行器和在样品附近放置一个低噪声放大器将提供 优化的S/N，3)证明了设计可以扩展到X波段 并集成到市售的光谱仪和低温恒温器中。

DESCRIPTION: A new type of resonator for EPR spectroscopy was developed with support of Innovative Technology Grant (RR09882). The crossed-loop resonator (CLR) consists of two, virtually-independent, lumped-element resonators that have a common sample volume where the loops of the two resonators meet orthogonally. The first resonator excites the spins, and the second resonator detects only the signal caused by the spin system. The phase noise of the source is reflected back to the source and is efficiently isolated (70 dB) from the EPR signal. The CLR eliminates the need for the microwave circulator used in conventional spectrometers to direct the EPR signal to the detector. The CLR essentially eliminates the source phase noise in the detected signal, increases spectrometer sensitivity, and allows dispersion spectra to be measured in the same high signal to noise (S/N) as absorption spectra. Because the baseline of the signal is stable with the CLR, magnetic field modulation can be replaced with superheterodyne detection, which will not cause the signal distortion (passage effects) that occur with field modulation. For pulse experiments the CLR greatly decreases the deadtime of the instrument and allows measurement of a portion of the signal previously inaccessible. Eliminating the circulator allows putting a low-noise amplifier near to, and cooled along with, the sample, greatly increasing S/N. It is now proposed to further develop the CLR in three major ways that are important for EPR measurements of biological samples, particularly at cryogenic temperatures: 1) Show that superheterodyne detection will provide a less distorted signal and higher signal-to-noise (S/N) than field modulation, 2) Show that eliminating the circulator and putting a low-noise amplifier near the sample will provide optimum S/N, and 3) Demonstrate that the design can be extended to X-band and incorporated into commercially available spectrometers and cryostats.