Rami Arieli: "The Laser Adventure" Section 6.5.2 page 2
Applications of x-Ray Lasers
Lasers operating in the x-Rays spectrum range can be used as a sophisticated weapon system. Thus, most of the research on x-Ray laser is done in the US national laboratories.

One of the most promising energy sources for exciting an x-Ray laser is nuclear energy(!).

One of the programs in the Strategic Defense Initiative (SDI) was to use a nuclear explosion to pump a large number of x-Ray lasers. An artist sketch of such system is described in figure 6.38.

Figure 6.38: An artist sketch of a nuclear blast to pump x-Ray lasers in space.