-----Original Message----- From: mix...@bigpond.com ...however there are no electronic transitions that match gamma energies of several MeV. Though Uranium will absorb x-rays of 115 keV.
Robin is correct on this. Photons of light, UV or even soft x-rays can be downshifted efficiently by specialty engineered structures or even by tuned photons of light to increase efficiency, but not gamma ray photons. Photons of light have electronic transitions which can be matched with molecular or atomic sized structures, since the wavelengths are long enough, typically half a micron for visible light, but gamma rays are hundreds of times shorter in wavelength and there is no atomic structure in nature which can become resonant and absorb. It is as simple as that. Thus, there is no known way to effectively shield gammas above the 100 keV energy range mentioned by Robin, whereas gammas from deuterium fusion are typically above 1 MeV - up to 24 MeV. Lots of money has been spent trying to do this, since there would be a big advantage to power aircraft with nuclear reactors. And as always, there is this caveat, which even the experts overlook. It is not the inability to shield some gamma rays which is the insurmountable problem, but the inability to shield 100% without exception. There is no room for error. Partial shielding is as useless as a screen door on a submarine. 24 MeV radiation is so deadly that even if one part per billion escapes - when an experiment is running at the kilowatt level of thermal gain, as Rossi claims, then the experimenter is fried within minutes. Very few industrial processes can be engineered at such high reliability. It makes no sense to dwell on the issue of reliable gamma downshifting in LENR. It simply cannot happen.
