A Wire-Crossed-Loop Resonator for Rapid Scan EPR
A Wire-Crossed-Loop Resonator for Rapid Scan EPR
复制标题
DOI：
10.1002/cmr.b.20161
复制
发表时间：
2010-04-01
影响因子：
0.9
通讯作者：
Eaton, Gareth R.
中科院分区：
文献类型：
--
作者：
Rinard, George A.;Quine, Richard W.;Eaton, Gareth R.
一个交叉环（正交模式）谐振器（QRST）构造的细线，以实现快速扫描在体内EPR成像在VHF频率（在实践中，近250 MHz）的设计目标。该应用要求谐振器具有非常开放的设计，以便于在图像采集期间接近动物以获得生理支持。快速扫描实验使用大幅度磁场扫描，以及足够大的谐振器和检测带宽来记录快速变化的信号响应。快速扫描EPR对RF/微波源噪声和与场扫描相干的基线变化敏感。对源噪声的敏感性是使用ADC将检测到的信号与RF源噪声隔离的主要动机。在两种谐振器设计中实现了44和47 dB的源噪声隔离。先前的结果表明，涡流有助于快速扫描EPR中的背景问题，因此，该设计必须最大限度地减少导电金属部件。使用细（AWG 38）线用于谐振器减少了涡电流并且降低了谐振器0，从而提供了更大的谐振器带宽。特定扫描频率下的机械共振是快速扫描背景的主要贡献者。(C)2010 Wiley Periodicals，Inc.概念Magn Reson部分B（Magn Reson工程）37 B：86-91，2010年
A crossed-loop (orthogonal mode) resonator (CLR) was constructed of fine wire to achieve design goals for rapid scan in vivo EPR imaging at VHF frequencies (in practice, near 250 MHz). This application requires the resonator to have a very open design to facilitate access to the animal for physiological support during the image acquisition. The rapid scan experiment uses large amplitude magnetic field scans, and sufficiently large resonator and detection bandwidths to record the rapidly-changing signal response. Rapid-scan EPR is sensitive to RF/microwave source noise and to baseline changes that are coherent with the field scan. The sensitivity to source noise is a primary incentive for using a CLR to isolate the detected signal from the RF source noise. Isolation from source noise of 44 and 47 dB was achieved in two resonator designs. Prior results showed that eddy currents contribute to background problems in rapid scan EPR, so the CLR design had to minimize conducting metal components. Using fine (AWG 38) wire for the resonators decreased eddy currents and lowered the resonator 0, thus providing larger resonator bandwidth. Mechanical resonances at specific scan frequencies are a major contributor to rapid scan backgrounds. (C) 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 37B: 86-91, 2010