POSED BY MODEL. Scanning electron microscope. Prof. Ken Snowdon using a combined scanning elec- tron microscope (SEM), scanning auger microscope (SAM) and scanning probe microscope (SPM). The SEM scans a sample with a beam of electrons. The beam may be scattered off the sample or it may cause it to emit electrons. The electrons are collected and translated into a three-dimensional image. The SAM can find the chemical composition of a sample on a microscopic scale. The SPM can image or alter material structures through the interaction of its probe with the material's surface. Snowdon is the Director of the Centre for Nanoscale Science and Technology at Newcastle University, England.