Reply To: Fusion Oil

[jamesr]

vansig wrote: Yes. It might look like this IR – UV PV cell, recently reported.
http://www.physorg.com/news188637189.html

I wonder if this works as well when x-rays scatter instead of being absorbed?

The x-rays will have a continuous spectrum of energies upto around 70keV (ie the electron Temperature). most of these will be photo-electrically absorbed creating an electron/ion pair (the electron gets pretty much all energy the photon had). At these energies a small proportion will be compton scattered one or more times before the photons will be absorbed. Note the level of PE absorption rises roughly with the 4th power of the matierial’s atomic number (& hence number of electrons as a possible target)

The primary high energy electron created by the absorption rips through the material ionizing thousands of atoms in its path, until it has slowed and given up all its energy. So if the ionization energy of the material is say 1.5eV, a 70keV primary electron will create 70000/1.5=~47000 secondary electrons. These would normally just recombine with the ions after a short time. To tap them off as an electric current you need the secondary electrons to be created in an insulating layer separated by two electrodes in which you apply a bias voltage to cause the electrons to drift to the anode & ions/holes to the cathode. If the insulator layer is too thick then the electrons will still have a chance of recombining & hence lower the efficiency

So you want thin foil electrodes made of a light metal, separated by insulator/semi-conductor layers with a high proportion of heavy elements to absorb the x-ray photons, and allow the drift of the secondary electrons to form a current.