ESR MICROSCOPE MKII MAGNETIC FIELD STABILIZTION SYSTEM

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 我们目前的Ku波段ESR微成像系统包括一个大的(15英寸极面)阻性磁体，它为ESR微成像(ESRM)的开发提供了良好的工作空间，但由较旧的瓦里安V-2500线性稳压电源供电，我们已将几个离散反馈系统拼接在该电源上，以实现精确的场调节。目前的反馈系统包括一个霍尔输入现场拨号控制台、一个湖岸型475霍尔场控制器和一个改进的瓦里安V-4542场/频率锁定(FFL)系统，该系统由EPR探头和信号处理电子设备组成。尽管到目前为止，该系统的性能总体上令人满意，但其可靠性微乎其微，特别是在(霍尔稳定的)磁场调节模式下进行设置时，从操作的角度来看，它的使用是不必要的复杂。 在升级到新的15kW Gensys磁铁电源(子项目0218)的过程中，我们建议用新设计的混合系统取代现有的调节系统，该系统结合了现有的Lakeshore 475霍尔场控制器和瓦里安V-4542场/频锁定探头，为Gensys电源增加了必要的模式控制电子设备和通信通道。这种高度集成的调节系统还将包括可编程的精密基准，以抵消相对较低的分辨率(16位)湖岸控制器输出，以实现ca 20b/10 mg分辨率至1.0T。还可以根据需要包括用于输入抖动的选项。目前的设计规范中包含了对可编程现场调节参数和功能模式进行完全远程控制的规定，以便系统能够与ESRM LabVIEW VI(虚拟仪器)软件兼容运行。 我们计划在第二个混合调节系统的构建中使用基本上相同的设计，为我们拟议的35 GHz ESR显微镜(子项目0138)提供霍尔/FFL磁场控制。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Our current Ku-band ESR microimaging system includes a large (15 inch pole face) resistive magnet that provides good working space for ESR microimaging (ESRM) development purposes but is powered by an older Varian V-2500 linear regulated power source to which we have attached a patchwork of several discrete feedback systems for the purpose of accurate field regulation. Currently the feedback systems include a Hall-input Field Dial console, a Lakeshore model 475 Hall field controller and a modified Varian V-4542 field/frequency lock (FFL) system consisting of EPR probe and signal processing electronics. Although this system has performed in a generally satisfactory manner to date, its reliability is marginal, particularly when operating in (Hall-stabilized) field regulation mode for setup purposes, and its use, from an operational viewpoint, is unnecessarily complicated. During the course of upgrading to the new 15KW Gensys magnet power supply (Subproject 0218), we propose replacing the existing regulation system with a newly-designed hybrid system incorporating the present Lakeshore 475 Hall field controller and Varian V-4542 field/frequency lock probe, adding the necessary mode control electronics and communication channel to the Gensys power source. This highly integrated regulation system will also include the programmable precision reference required for offsetting the relatively low resolution (16bit) Lakeshore controller output to achieve ca 20b/10 mG resolution to 1.0T. An option for input dithering can also be included as may be required. Provision is included in current design specification for full remote control of programmable field regulation parameters and functional modes so that the system can operate compatibly with the ESRM LabView VI (virtual instrument) software. We plan to employ essentially the same design in the construction of a second hybrid regulation system to provide Hall/FFL magnetic field control for our proposed 35 GHz ESR microscope (Subproject 0138).