INNOVATIVE RESONATOR FOR BIOMEDICAL EPR SPECTROSCOPY

用于生物医学 EPR 光谱的创新谐振器

• 批准号: 2772047
• 负责人: George Allen Rinard
• 金额: $ 17.05万
• 依托单位: UNIVERSITY OF DENVER (COLORADO SEMINARY)
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-15 至 2000-08-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2772047
• 关键词: biomedical equipment development; cryoscience; cryostat; electron spin resonance spectroscopy; magnetic field

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.

描述：开发了一种新型的EPR光谱谐振器 在创新技术赠款的支持下（RR09882）。 交叉环 谐振器（CLR）由两个，几乎独立的，集团的元素组成 具有共同样品量的谐振器，其中两者的回路 谐振器正交会见。 第一个谐振器激发了旋转，并激发 第二个谐振器仅检测由自旋系统引起的信号。 这 源的相位噪声反映回源，并有效 从EPR信号中分离出（70 dB）。 CLR消除了对 传统光谱仪中用于指导EPR的微波循环器 向检测器发出信号。 CLR基本上消除了源阶段 检测到的信号中的噪声，增加光谱仪的灵敏度，并允许 分散光谱将以相同的高信号和噪声（S/N）的测量与 吸收光谱。 因为信号的基线与 CLR，磁场调制可以用超胆道替换 检测，不会引起信号失真（通过效应） 发生现场调制。 对于脉冲实验，CLR很大 减少仪器的死时间并允许测量部分 以前无法访问的信号。 消除循环器允许 将低噪声放大器放在附近并与样品一起冷却 大大增加了S/N。 现在建议进一步发展 对于生物学的EPR测量很重要的三种主要方法 样品，特别是在低温温度下：1）表明 超墨件检测将提供较不扭曲的信号，较高的信号 信号到噪声（S/N），而不是场调制，2）表明消除 循环器并将低噪声放大器放在样品附近 最佳S/N，3）证明设计可以扩展到X波段 并掺入市售的光谱仪和低温稳定器中。