At 9:29 AM 2/8/5, Frederick Sparber wrote: >Horace Heffner wrote: > >> >> Energetically effective fusion created using electron beams I think is >>or would be essentially >> electron catalysed fusion. This requires a minimum beam intensity of >> 1x10^19 electrons/(cm^2*s), >> >Commercially available Electron Beam Welders can put 3.10e-18 electrons >per second >into a weld piece with a 150 Kev - 0.4 millimeter diameter beam .
OK, so that's a beam intensity of (3x10^18 electrons/sec)/(Pi*(0.02cm)^2) = 2.39x10^21 electrons/(cm^2*s), which is about 2000 times the minimum intensity, thus very good. The principle remaining problem is target vaporization and destruction of the confinement. It might be better to operate with a pulsed electron supply. >> >> but I think improves with increased intensity. >> Achieving a fast, dense, and high energy electron flux imposed on >> inertially confined hydrogen might best be done using x-rays, however. >> > >The problem with generating x-rays with electrons, is the low generation >efficiency: > >X-ray yield (%) = 1.216e-7 * Z * Volts (about 1% efficiency for >tungsten, Z = 74) I don't understand this. If the source is 1.216x10^8 volts the efficiency is 740 percent? The above only applies in some range? > >Also collimating them is a bit of a problem as they are finding out with >laser-generated x-rays. Yes. In a lab x-rays can be focused by refraction using lenses made out of pitch, etc., or by use of reflection at high incidence off the inside of lots of small metal tubes. Parabolic reflection might be inefficient to impossible depending on energy. > >At these energies the x-rays undergo the Compton (Scattering) Effect >giving up to 1/3 their >energy to the electrons (about 60 Kev max.with 200 Kev x-ray photons). > >Frederick Yes, so with efficiency factors of 0.01 for x-ray generation and .33 for momentum exchange we get down to a net factor 0.0033, which is not insurmountable in pulsed mode. So, a pulse generator is needed that is much more than 100 times the current and whichis also about 3 times the voltage of the electron welder, but only briefly. Cooling pulsed x-ray tubes is less difficult than continuous duty tubes. The target could a multi-layer target, consisting of, for example, an outer jacket of x-ray transparent confinement material with highest Z possible, an LiD-LiT mixture, mixed with an x-ray reflecting/dispersing powder, a high-z confinement jacket, and an LiD-LiT core? Perhaps some layer in the scheme would best be a D-T loaded metal. It certainly would be quite a large effort to obtain a practical energy generating device, because the x-rays would have to come into the target from all directions. Perhaps a mono-directional device would be possible if the target were surrounded by a high z material (W or Pb) with a hole for the x-rays and a somewhat x-ray transparent confining plug, possibly a D-T loaded metal, like Ti. Just thinking out loud. Regards, Horace Heffner
