Impact of the plasma power on plasma-induced increase in absorption of fused silica

Columnar structures produced by DC magnetron sputtering can be altered by using RF biased sputtering or by exposing the film to nitrogen pulses during sputtering, and these techniques are being evaluated to refine the grain structure in sputtered beryllium films deposited on fused silica substrates. Beryllium is brittle, and fractures in sputtered beryllium films tend to be intergranular; therefore, a convenient technique to analyze grain structure in these films is to fracture the coated specimens and examine them in an SEM. However, fine structure in sputtered deposits is difficult to image in an SEM, and both the low density and the low secondary electron emission coefficient of beryllium seriously compound this problem. Secondary electron emission can be improved by coating beryllium with Au or Au-Pd, and coating also was required to overcome severe charging of the fused silica substrate even at low voltage. The coating structure can obliterate much of the fine structure in beryllium films, but reasonable results were obtained by using the high-resolution capability of an Hitachi S-800 SEM and either ion-beam coating with Au-Pd or carbon coating by thermal evaporation.

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Investigation of fused silica dynamic behaviour

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:2006134142 ◽

2006 ◽

Vol 134 ◽

pp. 929-934 ◽

Cited By ~ 2

Author(s):

F. Malaise ◽

J.-M. Chevalier ◽

I. Bertron ◽

F. Malka

Keyword(s):

Dynamic Behaviour ◽

Fused Silica

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Power Losses in RF Inductor of Ferrite-Free Closed-Loop Inductively-Coupled Low Pressure Mercury Lamps

Light & Engineering ◽

10.33383/2019-040 ◽

2020 ◽

pp. 89-94 ◽

Cited By ~ 1

Author(s):

Ekaterina V. Lovlya ◽

Oleg A. Popov

Keyword(s):

Closed Loop ◽

Low Pressure ◽

Mercury Vapour ◽

Plasma Power ◽

Power Losses ◽

Inductive Discharge ◽

Inductively Coupled ◽

Radial Inhomogeneity ◽

Transformer Model ◽

Rf Inductor

RF inductor power losses of ferrite-free electrode-less low pressure mercury inductively-coupled discharges excited in closed-loop dielectric tube were studied. The modelling was made within the framework of low pressure inductive discharge transformer model for discharge lamps with tubes of 16, 25 and 38 mm inner diam. filled with the mixture of mercury vapour (7.5×10–3 mm Hg) and argon (0.1, 0.3 and 1.0 mm Hg) at RF frequencies of 1, 7; 3.4 and 5.1 MHz and plasma power of (25–500) W. Discharges were excited with the help of the induction coil of 3, 4 and 6 turns placed along the inner perimeter of the closed-loop tube. It was found that the dependence of coil power losses, Pcoil, on the discharge plasma power, Ppl, had the minimum while Pcoil decreased with RF frequency, tube diameter and coil number of turns. The modelling results were found in good qualitative agreement with the experimental data; quantitative discrepancies are believed to be due skin-effect and RF electric field radial inhomogeneity that were not included in discharge modelling.

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