Abstract: A small, low cost, low power, and portable x-ray source that produces an x-ray flux that is sufficient to produce high quality x-ray images on suitable x-ray sensitive films. The source includes a vacuumated chamber that is filled with a heavy atomic weight gas at low pressure and an x-ray emitter. The chamber is in a magnetic field and an oscillating electric field and generates an Electron Cyclotron Resonance (ECR) plasma having a ring of energetic electrons inside the chamber. The electrons bombard the x-ray emitter which in turn produces x-ray radiation in a given direction. A pair of magnetic members generate an axisymmetric magnetic mirror trap inside the chamber. The chamber may be nested within a microwave resonant cavity and between the magnets, or the chamber and microwave cavity may be a single composite structure. The source is useful to make x-ray photographs virtually anywhere and may be battery powered.