Publication detail

Stability Analysis of Cold-Emission Cathodes with Epoxy Coating

KNÁPEK, A. GRMELA, L.

Original Title

Stability Analysis of Cold-Emission Cathodes with Epoxy Coating

Czech Title

Analýza stability studenoemisních katod s tenkou vrstvou epoxidu

English Title

Stability Analysis of Cold-Emission Cathodes with Epoxy Coating

Type

journal article

Language

en

Original Abstract

In this paper, the current stability analysis was performed on the cold-emission cathode covered by a thin epoxy film. Non-destructive spectroscopic method, which is based on measuring current fluctuations, has been used to determine cathodes quality, which directly influents the stability of the emission current. Our investigations have been performed on tungsten cathodes with extra-sharp nanotip, operating under the HV (high-vacuum)conditions, usually in vacuums of 10-5 Pa order. All the cathodes used for this experiment have been prepared in our lab by improved electrochemical etching method, which is based on the presence of increased surface tension allowing reaching the geometrically precise shape of the cathode tip. After the two phase etching method, the tip was cleared and covered by thin epoxy film, which prevents the tip to be destroyed by ion bombardment that is caused by ions attracted back on to the cathode surface. A comprehensive investigation was carried out to determine particular noise sources and to compare clean cathodes with the resin-coated one, in order to describe the influence of the oxide and dielectric epoxy layer on to the emission current stability. Spectra obtained, for various emission currents at different voltages, are described and explained. The results suggest that the resin-layer changes cathode performance and extends its durability.

Czech abstract

Tento článek pojednává o analýze proudové stabiliy, jež byla provedena na studenoemisních katodách, pokrytých tenkou epoxidovou vrstvou. Nedestruktivní spektroskopická metoda, která je založená na měření proudových fluktuací, byla využita k posouzení kvality katody, která přímo ovlivňuje stabilitu emisního proudu. Náš výzkum byl proveden na wolframových katodách s extra tenkým (ostrým) hrotem, pracujícím v podmínkách vysokého vakua, obvykle v řádech 10-5 Pa. Veškeré naše katody byly připraveny laboratorně za pomoci vylepšené metody elektrochemického leptání, která je založená na zvýšené rychlosti leptání díky působení povrchového napětí kapaliny, což umožnuje dosáhnout geometricky přesný tvar hrotu katody. Po dvou fázích leptání je hrot očištěn a pokryt tenkou vrstvou epoxidu, která ho chrání před zničením vlivem bombardování zbytkových jontů, které jsou přitahovány zpět na hrot katody. Byl proveden srovnávací výzkum, abychom určili zdroje šumu a porovnali katody s čistým hrotem, s katodami potaženými epoxidovou pryskiřicí, za účelem popisu vlivu vrstev oxidu a epoxidu na stabilitu emisnícho proud. Získaná spektra, pro různé emisní proudy, při různých napětích, byla popsána a vysvětlena. Výsledky naznačují, že vrstva epoxidu na povrchu hrotu katody má přímý vliv na provoz katody a na její životnost.

English abstract

In this paper, the current stability analysis was performed on the cold-emission cathode covered by a thin epoxy film. Non-destructive spectroscopic method, which is based on measuring current fluctuations, has been used to determine cathodes quality, which directly influents the stability of the emission current. Our investigations have been performed on tungsten cathodes with extra-sharp nanotip, operating under the HV (high-vacuum)conditions, usually in vacuums of 10-5 Pa order. All the cathodes used for this experiment have been prepared in our lab by improved electrochemical etching method, which is based on the presence of increased surface tension allowing reaching the geometrically precise shape of the cathode tip. After the two phase etching method, the tip was cleared and covered by thin epoxy film, which prevents the tip to be destroyed by ion bombardment that is caused by ions attracted back on to the cathode surface. A comprehensive investigation was carried out to determine particular noise sources and to compare clean cathodes with the resin-coated one, in order to describe the influence of the oxide and dielectric epoxy layer on to the emission current stability. Spectra obtained, for various emission currents at different voltages, are described and explained. The results suggest that the resin-layer changes cathode performance and extends its durability.

Keywords

cold emission cathode stability, noise diagnostics

RIV year

2011

Released

27.06.2011

Publisher

Západočeská Univerzita

Location

Plzeň

Pages from

1

Pages to

5

Pages count

5

URL

BibTex


@article{BUT72480,
  author="Alexandr {Knápek} and Lubomír {Grmela}",
  title="Stability Analysis of Cold-Emission Cathodes with Epoxy Coating",
  annote="In this paper, the current stability analysis was performed on the cold-emission cathode covered by a thin epoxy film. Non-destructive spectroscopic method, which is based on measuring current fluctuations, has been used to determine cathodes quality, which directly influents the stability of the emission current. Our investigations have been performed on tungsten cathodes with extra-sharp nanotip, operating under the HV (high-vacuum)conditions, usually in vacuums of 10-5 Pa order. All the cathodes used for this experiment have been prepared in our lab by improved electrochemical etching method, which is based on the presence of increased surface tension allowing reaching the geometrically precise shape of the cathode tip. After the two phase etching method, the tip was cleared and covered by thin epoxy film, which prevents the tip to be destroyed by ion bombardment that is caused by ions attracted back on to the cathode surface. A comprehensive investigation was carried out to determine particular noise sources and to compare clean cathodes with the resin-coated one, in order to describe the influence of the oxide and dielectric epoxy layer on to the emission current stability. Spectra obtained, for various emission currents at different voltages, are described and explained. The results suggest that the resin-layer changes cathode performance and extends its durability.",
  address="Západočeská Univerzita",
  chapter="72480",
  institution="Západočeská Univerzita",
  journal="ElectroScope - http://www.electroscope.zcu.cz",
  number="2",
  volume="2011",
  year="2011",
  month="june",
  pages="1--5",
  publisher="Západočeská Univerzita",
  type="journal article"
}