Multipurpose EPR loop-gap resonator and cylindrical TE011 cavity for aqueous samples at 94 GHz
Multipurpose EPR loop-gap resonator and cylindrical TE011 cavity for aqueous samples at 94 GHz
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DOI：
10.1063/1.2709746
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发表时间：
2007-03-01
影响因子：
1.6
通讯作者：
Hyde, James S.
中科院分区：
文献类型：
--
作者：
Sidabras, Jason W.;Mett, Richard R.;Hyde, James S.
使用Ansoft（Pittsburgh，PA）高频结构仿真器（HFSS;版本10.0）设计了用于W波段（94 GHz）的环隙谐振器（LGR）和圆柱形TE 011谐振腔。使用Ansoft麦克斯韦3D（版本11.0）分析场调制穿透。将两个谐振器优化为相同的样本大小表明，LGR和TE 011的EPR信号强度相似。LGR的3 dB带宽约为1 GHz，是高频实验的新优势。超精密电火花加工（EDM）是用来制造谐振器从银。TE 011腔体具有切入主体的槽，以允许100 kHz场调制的穿透。谐振器主体嵌入石墨中，也通过EDM技术切割，出于包括以下原因的组合：（i）减少的微波泄漏和改进的TE 011模式纯度，（ii）场调制穿透，（iii）对腔体的结构支撑，以及（iv）通过EDM的机械加工性。两种谐振器都使用开槽虹膜。可变耦合由三短截线调谐元件提供。设计用于固定样品管的夹头系统已经实现，增加了样品放置的可重复性并降低了样品振动噪声。初步结果包括多量子实验高达9 Q使用LGR检查1 mM的2，2，6，6-四甲基哌啶-1-氧基（克里思）在水溶液中，在室温和场调制实验中使用TE 011腔，以获得1 μ M克里思的EPR谱。(c)2007年，美国物理学会。
A loop-gap resonator (LGR) and a cylindrical TE011 cavity resonator for use at W band, 94 GHz, have been designed and characterized using the Ansoft (Pittsburgh, PA) high frequency structure simulator (HFSS; Version 10.0). Field modulation penetration was analyzed using Ansoft MAXWELL 3D (Version 11.0). Optimizing both resonators to the same sample sizes shows that EPR signal intensities of the LGR and TE011 are similar. The 3 dB bandwidth of the LGR, on the order of 1 GHz, is a new advantage for high frequency experiments. Ultraprecision electric discharge machining (EDM) was used to fabricate the resonators from silver. The TE011 cavity has slots that are cut into the body to allow penetration of 100 kHz field modulation. The resonator body is embedded in graphite, also cut by EDM techniques, for a combination of reasons that include (i) reduced microwave leakage and improved TE011 mode purity, (ii) field modulation penetration, (iii) structural support for the cavity body, and (iv) machinability by EDM. Both resonators use a slotted iris. Variable coupling is provided by a three-stub tuning element. A collet system designed to hold sample tubes has been implemented, increasing repeatability of sample placement and reducing sample vibration noise. Initial results include multiquantum experiments up to 9Q using the LGR to examine 1 mM 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) in aqueous solution at room temperature and field modulation experiments using the TE011 cavity to obtain an EPR spectrum of 1 mu M TEMPO. (c) 2007 American Institute of Physics.