Neutron emission during a nanosecond discharge in deuterium in a nonuniform electric field

Neutron emission during a nanosecond deuterium discharge formed at the nonuniform electric field is investigated. A stable neutron yield is observed when the cathode is made of metallic plates covered by a layer of deuterated zirconium and the anode is made of stainless steel in the form of a tube. It is shown that, when the deuterium pressure equals several Torr, neutrons are emitted from both deuterated and deuterium-free cathodes. The influence of the anode design on the neutron yield is studied.     

Effect of gas pressure on amplitude and duration of electron beam current in a gas-filled diode

The parameters of an electron beam generated in helium in the pressure range p = 10⁻⁴−12 atm are studied. Nanosecond high-voltage pulses are applied to a gap between a tubular cathode and planar anode, which is made of 45-μm-thick AlBe foil. Behind the anode, an electron beam is detected at a helium pressure of 12 atm. The pressure dependence of the beam current amplitude shows three peaks at p ≈ 0.01, ≈ 0.07, and ≈ 3 atm. The beam-induced glow of a luminescent film placed behind the foil and the discharge glow at different helium pressures in the gas-filled diode are photographed.     

Effect of the Radiation Power Density on the Sensitivity of a Diamond Detector

This paper presents the results of an experimental study of the sensitivity of a detector made of natural diamond of the IIa type as a function of the power density of the radiation of a pulsed xenon lamp. It has been shown that the sensitivity of the detector depends on the power density of the xenon lamp radiation and equals about (1–6)·10^–4 A/W. A monotonic decrease in sensitivity of the detector during a radiation pulse has been detected. The minimum resistance of the diamond crystal with an irradiated face of area 3 mm², placed 7 mm away from the axis of the xenon lamp, was 300 , which corresponds to a specific conductivity of 2.2 ^–1·m^–1.     

UV and VUV excilamps excited by glow, barrier and capacitive discharges

An investigation was made into the characteristics of XeCl (5~308 nm), KrCl (5~222 nm) and XeI (5~253 nm)capacitive HF discharge and glow discharge excilamps. High fluorescence efficiency of the exciplex molecules has been obtained from excilamps with simple design under capacitive HF discharge excitation. A fluorescence efficiency with respect to the electrical power deposition of up to ~12% has been measured. The study of XeCl, KrCl and XeI excilamps has shown that it is possible to create sealed-off excilamps with gas mixture lifetimes of over 1000 hours.     

High-pressure runaway-electron-preionized diffuse discharges in a nonuniform electric field

High-pressure nanosecond diffuse (volume) discharges in a nonuniform electric field are studied experimentally using a recording system with a ?100-ps time resolution. As the voltage pulse shrinks to a width of ≈100 ps, the initiation of a diffuse discharge without a source of additional ionization is facilitated; specifically, a runaway-electron-preionized diffuse discharge is ignited in atmospheric-pressure air in the case of short interelectrode gaps. It is found that a major energy deposit into the plasma of this discharge is from an abnormal glow discharge following a maximum of the gap voltage.     

On the initiation of a spark discharge upon the breakdown of nitrogen and air in a nonuniform electric field

Switchover from a runaway-electromnduced volume discharge to a spark is studied when a nanosecond discharge is initiated in high-pressure nitrogen an d air at a voltage of 50–250 kV. In the case of a cathode with a small radius of curvature and a flat anode and in the presence of cathode spots, the leader of the spark channel may propagate from the flat cathode. When the rate of rise of the voltage across centimeterwide gaps is high (dU/dt ∼ 10¹⁵ V/s or higher), cathode spots in the case of a corona discharge emerge within 200 ps.     

One- and two-barrier excilamps on xenon dimers operating in the VUV range

Spontaneous emission sources in the VUV range based on one- and two-barrier pulsed-periodic gas (Xe) discharges are experimentally investigated. Volt-coulomb figures, as well as typical waveforms of current pulses and discharge voltage are presented. The time dependences of the voltage drop across the gas-discharge plasma, excitation power, and excitation energy are calculated. The radiation power versus xenon pressure, exciting pulse repetition rate, and average excitation power is determined. The radiation power average densities for one- and two-barrier excilamps are found to be 20–30 and ～40 mW/cm², respectively.     

Generation of runaway electron subnanosecond pulses in nitrogen and helium at a voltage of 25 kV across the gap

The formation of a runaway electron beam in helium and nitrogen at a generator voltage of 25 kV is studied experimentally. At low generator voltages, an ultrashort avalanche electron beam (UAEB) is shown to form at the flat top of the voltage pulse and its delay time relative to the leading edge of the pulse may attain several tens of nanoseconds. The conditions of runaway electron beam generation depend on the pressure in the gas-filled diode. The FWHM of the beam current varies from 200 ps to several nanoseconds. Beam electron energy distributions at different pressures are obtained. It is found that, if the gap is preionized by an additional source, the UAEB generation conditions break.