Scanning Proton-Induced X-ray Microspectrometry in an Atmospheric Environment

Abstract
Collimated million-electron-volt proton beams, brought out into air, can be used as a scanning microprobe to examine specimens with a spatial resolution of the order of 1 micrometer. Trace elements at concentrations as low as 1 part per million can be detected. Some preliminary results based on the use of this simple method are presented.