Oliver C. Wells' Vision: Use of Low-Loss Electrons to Enhance and Measure the Surface Detail in the Scanning Electron Microscope at High Resolution

Low-loss electron (LLE) imaging in the scanning electron microscope (SEM) is based on the collection of backscattered electrons that have undergone minimal elastic interactions within a sample and therefore carry high-resolution, surface-specific information. Oliver Wells credits the concept of filtering the high-energy emitted electrons in the SEM to a statement made by McMullan [2], that the signal collected in the SEM could be “...restricted to the electrons which have lost only small amounts of energy and which have therefore travelled only short distances through the specimen.” But, it was Oliver Wells who carried this concept forward to become the viable LLE imaging technique [3, 4]. He developed the theory, designed and assembled a working LLE detector capable of demonstrating that concept. For many years, he researched and refined the LLE technique to fulfill his vision of collecting the highest resolution surface information possible from the SEM.