Chzhan M, Kuppusamy P, Samouilov A, He G, Zweier J L
Department of Medicine, Division of Cardiology and the EPR Center, Johns Hopkins Medical Institutions, 5501 Hopkins Bayview Circle, Baltimore, Maryland 21224, USA.
J Magn Reson. 1999 Apr;137(2):373-8. doi: 10.1006/jmre.1998.1689.
There has been a need for development of microwave resonator designs optimized to provide high sensitivity and high stability for EPR spectroscopy and imaging measurements of in vivo systems. The design and construction of a novel reentrant resonator with transversely oriented electric field (TERR) and rectangular sample opening cross section for EPR spectroscopy and imaging of in vivo biological samples, such as the whole body of mice and rats, is described. This design with its transversely oriented capacitive element enables wide and simple setting of the center frequency by trimming the dimensions of the capacitive plate over the range 100-900 MHz with unloaded Q values of approximately 1100 at 750 MHz, while the mechanical adjustment mechanism allows smooth continuous frequency tuning in the range +/-50 MHz. This orientation of the capacitive element limits the electric field based loss of resonator Q observed with large lossy samples, and it facilitates the use of capacitive coupling. Both microwave performance data and EPR measurements of aqueous samples demonstrate high sensitivity and stability of the design, which make it well suited for in vivo applications.
一直以来都需要开发经过优化的微波谐振器设计，以在体内系统的电子顺磁共振（EPR）光谱学和成像测量中提供高灵敏度和高稳定性。本文描述了一种新型的具有横向电场（TERR）和矩形样品开口横截面的凹腔谐振器的设计与构建，用于体内生物样品（如小鼠和大鼠的全身）的EPR光谱学和成像。这种具有横向电容性元件的设计，通过在100 - 900 MHz范围内微调电容极板的尺寸，能够在750 MHz时实现中心频率的宽泛且简单的设置，此时空载品质因数约为1100，而机械调节机制允许在+/-50 MHz范围内进行平滑连续的频率调谐。电容性元件的这种取向限制了在处理大的有损样品时观察到的基于电场的谐振器Q值损耗，并且便于使用电容耦合。微波性能数据和水性样品的EPR测量都证明了该设计具有高灵敏度和稳定性，使其非常适合体内应用。
