An illustrated example ionization device includes a pyroelectric electron accelerator that causes electrons to move away from the accelerator. A silicon target is positioned in a path of the electrons. X-ray radiation results from the electrons colliding with the target. In one example embodiment, the electrons moving between the accelerator and the target have energy up to 60 KeV and the target attenuates the energy so that the x-ray radiation has energy between 1 KeV and 3 KeV.