Low-power table-top fusion
>I'm not a physicist, but I know fision is a lot easier than fusion, right?
Fission is easier than fusion in general, but NOT in deuterium! (Uranium fission is a heck of a lot easier than deuterium fusion, basically because the U nucleus is large and rather unstable in the first place -- hit it with a neutron and it will break apart easy). It's pretty damn hard to just split a deuterium nucleus -- essentially impossible with a laser . Anyway, the neutrons come from fusion, and this is not at all surprising - no need to specifically look for He.