Hence, the term, PHOTON ACCELERATOR, came into being.
Yep, though I see that phrase with what should be described as laser particle accelerators. First read about this concept I think in 1999 about hafnium 178-m in an article called "Light Plays Tricks with Nuclei" (search on google). One study said they had something like a 60 to 1 return on the x-ray energy that they radiated onto the hafnium 178m sample. Later another study refuted it so I'm not sure what the status is on the subject.
But the idea is enormous. If we can stimulate the emission of gamma rays from a americium 242m sample there will be nothing this side of fusion that is more powerful. It would open up the solar system . Easily. Do you know anything about this subject?