The study of the flow of ions

1. The temporary nature of the flow of ions
2. The formation of ion spectrum
3. Ion flow to the cathode surface

The study of flow of electrons

1. The presence of a high-energy component in the electron spectrum
2. Temporal studies of anomalous electrons

The study of the flow of ions

Method

For research, a single-channel electrostatic energy analyzer is used, combined with a time-of-flight mass analyzer (Fig. 1). This analyzer is used in the mode of energy-mass analysis, or in the mode of temporary analysis of the flow of particles of one energy.

Fig. 1. Energy-mass analyzer; 1 – input unit, 2 and 3 – lower and upper plates of the energy analyzer, 4 – collector, 5 – span pipe, 6 – detector.

1. The temporary nature of the flow of ions

   As a result of measurements of the ion flow for one isolated energy, the peak character of the flow was revealed. Ions are emitted by arc plasma intense beams with a characteristic appearance time of 200 – 500 ns. There is no constant (continuous) flow (Fig. 2). Different charge fractions are emitted at the same time, and the charge composition varies from release to release. The greatest surge of ion flow occurs at the end of the arc.

   

   Fig. 2. Mo ion flow at 20 A current and 42 eV energy.

2. The formation of ion spectrum

   The consequence of the peak character of the ion flow is the mechanism of formation of the resulting (stationary) energy-mass spectrum of ions. During high-speed measurements of the energy-mass spectrum, when the time of scanning the analyzer by energy was units of microseconds, individual measurements of the spectra were "torn" curves — a set of intense emissions. When averaging single spectra, a smooth well-known bell-shaped form was revealed. Based on these measurements, together with measurements of the temporal nature of the flow, it can be said that each specific emission has its own energy-mass composition, and previously published ion spectra make sense only as averaged spectra over a large measurement time.

3. Ion flow to the cathode surface

   Using a thin film burned by discharge as a cathode, it was possible to measure the characteristics of the ion flow to the cathode surface. Energy-mass-analysis has shown the presence of accelerated 1,2,3-fold charged ions with energies comparable with ion energies in the direction from the cathode current Measurement at a grounded probe under cathodic film showed presence of intense emission ion current strictly correspond to local lows of the discharge current.

The study of flow of electrons

1. The presence of a high-energy component in the electron spectrum.

   The analysis of the electron energy spectrum was discovered by a group of electrons with energies significantly greater than the burning voltage of the arc. The energy spread of the high-energy component is about 10 – 15 eV.

2. Temporal studies of anomalous electrons

   Temporary studies of the electron flow from the vacuum arc region were carried out using the method of the retarding potential. Two energy analyzers were used, located at different angles to the cathode surface and tuned to the energy above the arc voltage drop. Studies have revealed the following features of the electron flow: the electron flow is a sequence of intense peaks with a characteristic repetition time of 200–500 ns, the electron flow is sharply directed along the normal to the cathode surface, and the anode position does not play a role. Electrons are ejected synchronously in different directions (there are no narrowly directed jets), the largest surge of the flow occurs at the end of the arc.

Fig. 3. The flow of accelerated electrons. Delay voltage – 60 eV. Time – 100 ns per point, voltage 10 V per point, current 1 A per point.