Fast discharge (current rate ~10
12
A/s) through the gas filled conical cavity results in a convergent shock wave, originated on the inner wall of cavity. Special way of its cumulation is responsible ...for the close contact of hot plasma and cold working gas (Ar in our case), which makes possible the effective charge exchange between Ar IX ions and neutral Ar atoms. The article demonstrates the evidence of the presence of stimulated emission in transition between the levels 9
d
and 3
p
of Ar VIII (wavelength 10.78 nm). The conclusion has been deduced from the dependence of line intensity upon the number of conical cavities, connected in series. The result can be of interest for the elaboration of EUV sources.
This article presents the results of the low inductance vacuum spark plasma diagnostics obtained with the help of a microchannel plate (MCP) detector. Time-resolved pinhole camera images and ...extreme-ultraviolet (EUV) spectra were obtained for discharge plasma with a framing time in the nanosecond range. It was found that, in the case of an Al anode, discharge plasma undergoes filamentation with subsequent pinching. In the case of a Mo anode, the discharge plasma displays a stratified structure—a system of plasma layers oriented mostly normal to the discharge axis. The difference of the structure can be connected with the process of the erosion of anode at the stage of the discharge current growth. The EUV spectra of discharge plasma at the pinch stage showed the presence of Al ions up to Al VIII (ionization potential 284.6 eV) and Mo ions up to Mo XVII (ionization potential 646 eV).
The article presents the results of the study of electrons, emitted by the plasma of a low-inductance vacuum spark. It was found that a 50-kA discharge with a 3.4-µs period of current oscillations ...produces electrons with the energy higher than 100 keV, which leave the discharge plasma in the direction perpendicular to the discharge axis. The electrons have an energy spectrum close to monoenergetic. They appear after the first quarter period of discharge current oscillations and are emitted during about 1 µs. So, the origin of the electrons has no relation to the process of plasma pinching. The time behavior of the electron energy was studied. It gradually diminishes from a value of about 100 keV just after the maximum of the discharge current down to about 10 kV after reversal of the current direction. This phenomenon points out the redistribution of the discharge current, resulting in the disappearance of the magnetic field on the line of sight perpendicular to the discharge axis.
The article presents the experimental study of discharges in a conical cavity, filled with Ar at pressure 80 Pa. The electrical current driver (inductive storage with plasma erosion opening switch) ...supplies to the load electrical current pulse with growth rate about 1012 A s−1 and maximal value 30-40 kA. The convergent conical shock wave starts from the inner surface of the discharge cavity and collapses in 'zippering' mode. The pin hole camera imaging with MCP detector (time resolution 5 ns) have demonstrated the appearance of effectively fast moving compact plasma with visible velocity v = (1.5 ± 0.14) × 107 cm s−1. Plasma emits narrow band radiation in the spectral range of Rydberg series transitions of Ar VII, Ar VIII with quantum number up to n = 9 (wavelength about 11 nm). The intensity of radiation is comparable with the total plasma emission in the range 10-50 nm. Charge exchange between multiply charged Ar ions and cold Ar atoms of working gas is proposed as the possible mechanism of the origin of the radiation.
The results of an experimental study of the characteristics of a plasma-erosion opening switch, which is designed for operation in discharge circuits with inductive energy storing, are presented. The ...time dependences of the resistance of the opening switch, whose jump reaches 3 Ω, as well as the overvoltage that reaches 60 kV at an initial voltage at the main capacity of 30 kV, were determined. The opening switch provides a current rise rate of 0.5 × 10
12
A/s in a load with an inductance of up to 50 nH.
We have studied the spectra of xenon in the range 10–17 nm emitted in a fast conical discharge (
dI
/
dt
~ 10
12
A/s). Cumulation of a converging conical shock wave leads to the appearance of a hot ...plasma region effectively moving along the axis of the discharge. Under conditions of a limited spectral resolution (λ/δλ ~ 150), we have identified main observed lines. Our analysis of the spectra has shown that the plasma contains Xe XI ions, which are not observed in the case of a discharge with a cylindrical shock wave (a capillary discharge) occurring in the same discharge circuit. We have studied the time behavior of the spectra with a resolution of 35 ns. It has been shown that a hot plasma region exists during the first 150 ns of the discharge, then the plasma is subjected to the action of matter eroded from the inner wall of the discharge cavity.
The influence of the discharge cavity dimensions on the properties of the spherical plasma formed in a fast discharge was studied experimentally. The passage of a current pulse with an amplitude of ...30–40 kA and a rise rate of ~10
12
A/s (a fast discharge) through a spherical ceramic (Al
2
O
3
) cavity with an inner diameter of 11 mm filled with argon at a pressure of 80 Pa results in the formation of a 1- to 2-mm-diameter spherical plasma with an electron temperature of several tens of electronvolts and a density of 10
18
–10
19
cm
–3
. It is shown that an increase in the inner diameter of the discharge cavity from 11 to 21 mm leads to the fourfold increase in the formation time of the spherical plasma and a decrease in the average ion charge. A decrease in the cavity diameter to 7 mm makes the spherical plasma unstable.
We report on the development of plasma-based sources of extreme ultraviolet radiation for the next-generation lithography and mask inspection and the development of equipment for spectral diagnostics ...of such sources.
Off Rowland spectrometer with shifted slit Antsiferov, P.S.; Dorokhin, L.A.; Krainov, P.V.
EPJ Web of Conferences,
2017, Letnik:
132
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The article presents the scheme of grazing incidence spectrometer with the entrance slit shifted from the Rowland circle. This scheme allows to get the focusing surface normal to the line of site and ...to use the micro channel plate detector for the registration of the spectra. The results of the experimental tests are also given.
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