My first question is: is easier to reach D-D fusion than Be(alpha, neutron)C reaction?? In Am-Be neutron sources or similars, the yield of neutrons is too low compared with neutron tube sources, then, these last are too much expensive. So, it could be a good idea to modify the design of Farnsworth fusor placing a little ball of beryllium in the center of the inner grid, then making vacuum in the chamber and filling it with some miliTorr of ordinary helium. Helium atoms will be accelerated as deuterium does in ordinary fusors. These alpha particles will orbit constantly the beryllium ball and reacting with it's atoms, creating carbon and free neutrons.