ESR MICROSCOPE MKII MAGNETIC FIELD STABILIZTION SYSTEM

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。所列机构为 中心，不一定是研究者的机构。 我们目前的Ku波段ESR显微成像系统包括一个大的（15英寸极面）电阻磁铁，为ESR显微成像（ESRM）开发提供了良好的工作空间，但由一个较旧的瓦里安V-2500线性稳压电源供电，我们已经附加了几个离散反馈系统的拼凑，以实现精确的磁场调节。目前的反馈系统包括霍尔输入场拨号控制台、Lakeshore 475型霍尔场控制器和由EPR探头和信号处理电子设备组成的改进的Varian V-4542场/频率锁定（FFL）系统。尽管该系统迄今为止已经以大体上令人满意的方式执行，但是其可靠性是边际的，特别是当出于设置目的而在（霍尔稳定的）场调节模式下操作时，并且从操作的观点来看，其使用是不必要地复杂的。 在升级到新的15 KW Gensys磁体电源（子项目0218）的过程中，我们建议用一个新设计的混合系统取代现有的调节系统，该系统将现有的Lakeshore 475霍尔场控制器和Varian V-4542场/频率锁定探头结合在一起，为Gensys电源添加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，用于补偿相对较低分辨率（16位）的Lakeshore控制器输出，以实现约20 b/10 mG分辨率至1.0 T。还可以根据需要包括输入抖动选项。在当前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结构中采用基本相同的设计，为我们提出的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. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. 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).