You just heat the crystal from room temperature to about 130 degrees. Then you can use it while it's heating or while it's cooling. We're doing it while it's cooling. We're letting it cool back to room temperature, and while it's doing that it's accelerating ions, so it's like a particle accelerator that's very simple.
We published several papers explaining how these crystals produce X-rays and electron beams, and they're very efficient in doing this. So using low-energy X-rays or low-energy electron beams - by which I mean similar to the energies that are used currently in medical imaging rather than treatment - we can produce a really high dose of electrons that can penetrate a very thin layer of the skin. If such a device can produce high enough dose, then we can possibly use it for cancer treatment - and we're not far from this goal.
When you heat or cool the crystal . . . it becomes polarized. Because the crystal is an insulator, when it becomes polarized it essentially becomes a charged capacitor. The voltage output is the charge, which is big, divided by the capacitance, which is very, very small, thereby making the voltage swing huge--over 100,000 V on the face of each crystal.