INVESTIGADORES
MARQUEZ Adriana Beatriz
artículos
Título:
Spectroscopic Line Behavior in a DC Copper Vacuum Arc Operated with Background Gas
Autor/es:
D. GRONDONA; H. KELLY; A. MÁRQUEZ; A. LEPONE
Revista:
IEEE TRANSACTIONS ON PLASMA SCIENCE
Editorial:
IOP
Referencias:
Año: 2002 vol. 30 p. 391 - 396
ISSN:
0093-3813
Resumen:
The behavior of some selected visible spectral lines
emitted in the interelectrode space of a Copper vacuum arc operated
with background gases (mainly Oxygen gas) is determined
in terms of the gas filling pressure value. It is found that the behavior
of these CuI and CuII lines with the gas pressure value is
essentially the opposite: after an intensity plateau at low-pressure
values, the CuI line intensity grows, while the corresponding
CuII intensity decreases. On the other hand, no transitions corresponding
to CuIII were registered within the spectral range investigated
(340 to 600 nm). The measured line intensities are compared
with the particle densities calculated with a one-dimensional
model, which includes four metallic species (having no inner structure)
with different charge state, and takes into account ion slowing
down by elastic scattering with neutrals, radial diffusion loses to
the chamber wall, charge-exchange processes with neutrals and
ionization (or recombination) of the gas molecules (or gaseous ions)
by electron impact. It is inferred that the population of an excited
level responsible for a given emission line is much smaller (of the
order of 103104 cm 3) than those expected for the fundamental
levels of the particles. The explanation for the observed behavior of
these spectral lines with the pressure value rests on the local generation
of excited states from lower lying levels by electron impact,
but admitting the presence of a certain amount of metal vapor (generated
by microdroplet evaporation in the vicinities of the cathode
surface) in the interelectrode region.3104 cm 3) than those expected for the fundamental
levels of the particles. The explanation for the observed behavior of
these spectral lines with the pressure value rests on the local generation
of excited states from lower lying levels by electron impact,
but admitting the presence of a certain amount of metal vapor (generated
by microdroplet evaporation in the vicinities of the cathode
surface) in the interelectrode region.