SCAN-Lab Technical Notes 11: Determining the probe diameter and RG ratio in an SECM experiment

Introduction

When performing SECM measurements the diameter and the RG ratio of the Ultra MicroElectrode (UME) probe are of the utmost importance. As the diameter of the probe
ultimately determines the resolution of the experiment the probe is usually selected to be on the order of, or smaller than, the features of interest. The RG ratio is the ratio of the insulating sheath, which is ideally 10 or less for the most sensitive measurements. This note demonstrates how the probe diameter and RG ratio are determined.