Neutrons in a nanosecond low-pressure discharge in deuterium

Stable neutron generation with a yield of ~1.2×10^(4) neutrons per pulse was obtained during d(d,n)^(3)He reaction initiated by the high-voltage nanosecond discharge in a gap with a potential tungsten cylinder(anode)and a grounded deuterated zirconium plate(cathode)filled with deuterium at a pressure of ~10^(2) Pa.Estimated duration of the neutron pulse was ~1.5 ns.Less intensive neutron emission was registered without deuterated plate.Splashing of material of the tungsten electrode was observed during the high-voltage nanosecond discharge in the deuterium,hydrogen,helium and argon at pressures of 10^(2)-10^(4) Pa.

Influence of electrode spacing and gas pressure on parameters of a runaway electron beam generating during the nanosecond breakdown in SF_(6) and nitrogen

This study deals with experimental and theoretical simulation data showing the influence of electrode spacing and gas pressure on parameters of a supershort avalanche electron beam(SAEB)formed in SF_(6) and nitrogen at different rise times and amplitudes of a voltage pulse.Using GIN-55-01,VPG-30-200,and SLEP-150M pulsers,tubular cathodes with a diameter of 6 mm,as well as gaps of 3,5,and 8 mm,it was shown that the SAEB current amplitude can both increase and decrease depending on an electrode spacing,a waveform and a rise time of the voltage pulse,as well as the pressure of SF6 and nitrogen.It was established as a result of simulation that maximal voltage across the gap during the process of generation of runaway electrons and the thickness of an anode foil have a major effect on the SAEB current pulse amplitude.

Runaway electrons during subnanosecond breakdowns in high-pressure gases

The parameters of runaway electrons produced in nanosecond high-voltage discharges in different gases(air,nitrogen,sulphur hexafluoride,krypton,argon,methane,neon,hydrogen,helium)at atmospheric and higher pressure were studied.An optical analysis was also performed to investigate the ionisation dynamics in diffuse discharges in nitrogen and nitrogen-containing mixtures.At breakdown of a point-to-plane gap by nanosecond(≃2 ns)high-voltage(≃200 kV)pulses of negative voltage polarity and gas pressure above 0.1 MPa,a supershort avalanche electron beam(SAEB)was detected by a collector behind the flat anode.For pressure>0.1 MPa of nitrogen and other gases it is shown that the maximum pressure for SAEB registration decreases with increasing the voltage pulse rise time.Therefore,to detect a SAEB at atmospheric and higher gas pressure,one should use voltage pulses with an amplitude of hundred kilovolts and rise time of∼1 ns and shorter.The experimental research in the dynamics of optical radiation from the discharge plasma shows that the breakdown in which runaway electrons are produced develops as an ionisation wave.