Their current setup appears to be very low yield, whatever they are doing. Of course what they've built barely qualifies as proof-of-concept (assuming they are

Their current setup appears to be very low yield, whatever they are doing. Of course what they've built barely qualifies as proof-of-concept (assuming they are really seeing fusion). An energy production system proof-of-concept would probably be significantly different. Going from neutron kinetic energy to usable energy (eg. for electricity production) involves many intermediate steps. You will not be able to "harvest" all of the kinetic energy. Unfortunately, I don't know the technical details to calculate those types of yields. But they are not seeing much with their detector.