Microscopy with Protons

摘要

Electron microscopy is a mature technique for imaging structures and surfaces at resolutions well below the diffraction limit of light. An analogue of electron microscopy is proton microscopy, which uses high-energy protons. Although the technology for focusing protons is technologically more complex than for electrons (due to the much higher momentum of protons), proton microscopy has the unique feature of elemental mapping down to the parts-per-million level with high accuracy. The use of protons enables a suite of complementary techniques to be simultaneously utilised. Since the proton is the nucleus of a hydrogen atom, and is found in all nuclei, this suite of techniques is also known as nuclear microscopy (see box story).