Let me slightly correct that. Patent applications are now published 18 months after filing, whether or not the patent is issued, so everything will be public in six months’ time. Based on the USPO’s response time, it will probably take about two years from now, three years total, to actually get a patent.
There is a trade off in photo-electric devices between expense per unit area and efficiency. A more complex, multilayered system will be more efficient, but more expensive per unit area. But if you have a source that has a very high power per unit area, you can afford a higher expense per unit area, but still have a low expense per unit power. The DPF will be producing x-rays at a rate of megawatts/meter squared, as compared with a kW per meter squared or less for sunlight. So we can afford to make a much more efficient converter.