Number Of Emission Centers Research Articles

Evolution of the characteristics of a field-electron emitter based on nitrocellulose-carbon nanotube composite

Characteristics of a field-electron emitter based on a nitrocelulose-multiwalled carbon nanotube composite have been studied. A new method of the recording and online processing of current-voltage (I–U) characteristics of multipoint field-electron emitters has been developed for monitoring the evolution of their properties. Using this method, we have (i) determined the dependences of the field enhancement factor and number of emission centers on the interelectrode distance, (ii) discovered hysteresis of the I–V curve related to variation of the amplitude of applied voltage pulses, and (iii) revealed the influence of the initial emission current level on the temporal evolution of emitter properties.

Study of the time dependence of ionic crystal cathodoluminescence under conditions of electron-stimulated self-activation

A physical model with a variable number of emission centers is considered for calculating the time dependence of activated cathodoluminescence intensity. A system of two kinetic equations is solved to calculate I(t). The main model parameters are determined. The theoretical results are compared with the experimental data and their good correspondence is demonstrated.

Study of transients in the formation of heavy-current nanosecond electron beams

Results are presented from experimental and numerical studies of the spatial and temporal microstructure of a relativistic heavy-current electron beam of nanosecond duration. The beam is formed in a magnetically insulated coaxial diode with an edge-emitting cathode. Microcurrent oscillations and azimuthal nonuniformity of the beam are seen, the scale of the latter depending on the maximum cyclotron radius of the electrons. Two- and three-dimensional numerical calculations performed by the macroparticle method show that space-charge oscillations near the cathode produce these phenomena even in the case of a uniform emission surface. It is shown that the increase in the full current of the beam that occurs during the pulse in a weak magnetic field is connected with the gradual propagation of emission to the cylindrical outside surface of the cathode. A study is made of the effect of the discreteness of the emission surface on the impedance and current of the vacuum diode. The linear increase seen in current during the pulse with a small number of emission centers is attributed to an increase in their size as a result of expansion of the cathode plasma.

Spectrum of current fluctuations in emitter with random number of emission centers

Spectrum of current fluctuations in emitter with random number of emission centers

Intense Narrow Emission Band from the Surface of Powder of KI: Ag Crystal

Very intense emission has been found under the irradiation of N 2 Baser light from the surface of KI crystals which contain Ag + ion with high concentration. The number of emission centers grows with time soon after the crystal is ground into powder at room temperature. Ag + ions exsisting in the crystal surface play an important role in the formation of the emission centers. The emission band is usually centered at 427 nm with the half width as narrow as 0.05 eV at LNT. The emission decays very fast with a time at least less than 1 ns.