Neutron production in deuterium-noble gas mixtures in a plasma focus

Summary Form only given, as follows. Experiments on the DPF 78 plasma focus (60 kV, 28 kJ) have shown that neutron production occurs predominantly at the time of the hard X-ray pulse. This pulse is produced by a relativistic electron beam (REB). It has been shown that this REB is generated at the time of the plasma maximum compression, some 25 ns before the plasma becomes m=0 unstable. The neutron pulse is not observed if there is no REB. This fact and the correlation between the risetime of plasma optical emission and the risetime of the neutron pulse indicate that the neutrons have a beam-plasma origin at this time. The theory that the neutron emission could be produced by plasma hot spots has been investigated by studying the scaling as the high-Z dopant is varied. As the percentage of the Z dopant is increased the neutron emission decreases even though the number and brightness of the hot spots increase. A thermal origin is not completely dismissed, however, because on some shots a second neutron pulse was observed after the m=0 instability.<>