Neutron emission generated during wire array Z-pinch implosion onto deuterated fiber

摘要

The implosion of both cylindrical and conical wire arrays onto a deuterated polyethylene fiber was studied on the S-300 pulsed power generator [A. S. Chernenko et al., Proceedings of the 11th International Conference on High Power Particle Beams (Academy of Science of Czech Republic, Prague, 1996), p. 154]. Neutron measurements were used to obtain information about acceleration of fast deuterons. An average neutron yield approached 109 on the current level of 2 MA. In the case of conical wire arrays, side-on neutron energy spectra peaked at 2.48 +/- 0.05 MeV with 450 +/- 100 keV full width at half-maximum. In the downstream direction, the peak neutron energy and the width of a neutron spectrum were 2.65 +/- 0.10 MeV and 350 +/- 100 keV, respectively. The total number of fast deuterons was 1015 and their average kinetic energy was about 150 keV. Most of the deuterons were directed toward the cathode. The broad width of neutron spectra in the side-on direction implied a high radial component of deuteron velocity. With regard to the emission time, neutron pulses temporally correlated with hard x rays and also with measured voltage. The neutron emission lasted on average 30 +/- 5 ns and it was observed during the stagnation and at the beginning of the expansion of a plasma column. At this moment, the plasma impedance reached 0.2-0.4 Omega. In the post-stagnation phase, this value was formed significantly by enhanced plasma resistance. Similar experimental results were observed also with cylindrical wire arrays imploding onto a deuterated fiber. (C) 2008 American Institute of Physics.