A Kelvin probe based method for measuring the electron emission yield of insulators and insulated conductors subjected to electron irradiation

Belhaj, Mohamed; Tondu, Thomas; Inguimbert, Virginie; Chardon, Jean-Pierre

doi:10.1088/0022-3727/42/10/105309

Cited by 19 publications

(12 citation statements)

References 29 publications

(56 reference statements)

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“…The experimental facility used for EEY measurement is described in Ref. 16. The vacuum level is maintained below 5 Â 10 À7 mbar, thanks to a cryogenic pump associated with oil-free molecular-diaphragm pumps.…”

Section: Methodsmentioning

confidence: 99%

Electron-emission yield under electron impact of ceramics used as channel materials in Hall-effect thrusters

Tondu¹,

Belhaj²,

Inguimbert³

2011

Journal of Applied Physics

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We report measurement of electron-emission yield (EEY) under the impact of electrons on materials of Hall-effect-thruster (HET) interest: BN, BN-SiO 2 , and Al 2 O 3 . The effects of the material aging (under electron irradiation) on the yield of BN and Al 2 O 3 are investigated. The EEY of BN grows with electron exposure, whereas that of Al 2 O 3 reduces. A simple analysis of our experimental results indicates that these variations are most likely because of surface and near surface composition changes caused by the electron beam. The representativeness of EEY measurements on ceramics that have not suffered from the specific environment of a HET (ion and electron bombardment) is discussed.

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Section: Methodsmentioning

confidence: 99%

Electron-emission yield under electron impact of ceramics used as channel materials in Hall-effect thrusters

Tondu¹,

Belhaj²,

Inguimbert³

2011

Journal of Applied Physics

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“…The traditional method has two disadvantages. First, it needs to accurately calculate the neutralization dose, it is easy to have positive charge on the sample surface due to insufficient neutralization dose, or negative charge on the sample surface due to excessive neutralization; second, it needs to be equipped with another one low energy electron gun [24,25].…”

Section: The New Test Methods For Seementioning

confidence: 99%

“…We designed a spherical system for testing the SEE level of materials to ensure the full collection of secondary electrons and help improve the accuracy of the measurement results. And, we recommend using low-energy secondary electrons instead of low-energy electron beams for neutralization to measure the SEE of insulating materials, such as MgO and Al 2 O 3 , it avoids the disadvantages of neutralization dose and neutralization time [24,25], this method is convenient and low cost.…”

Section: Introductionmentioning

confidence: 99%

The Design of the Emission Layer for Electron Multipliers

et al. 2021

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The electron multipliers gain is closely related to the secondary electron emission coefficient (SEE) of the emission layer materials. The SEE is closely related to the thickness of the emission layer. If the emission layer is thin, the low SEE causes the low gain of electron multipliers. If the emission layer is thick, the conductive layer can't timely supplement charge to the emission layer, the electronic amplifier gain is low too. The electron multipliers usually choose Al2O3 and MgO film as the emission layer because of the high SEE level. MgO easy deliquescence into Mg(OH)2 Mg2(OH)2CO3 and MgCO3 resulting in the lower SEE level. The SEE level of Al2O3 is lower than MgO, but Al2O3 is stable. We designed a spherical system for testing the SEE level of materials, and proposed to use low-energy secondary electrons instead of low-energy electron beam for neutralization to measuring the SEE level of Al2O3, MgO, MgO/Al2O3, Al2O3/MgO, and precisely control the film thickness by using atomic layer deposition. We propose to compare the SEE under the adjacent incident electrons energy to partition the SEE value of the material, and obtain four empirical formulas for the relationship between SEE and thickness. Since the main materials that cause the decrease in SEE are Mg2(OH)2CO3 and MgCO3, we use the C element atomic concentration measured by XPS to study the deliquescent depth of the material. We propose to use the concept of transition layer for SEE interpretation of multilayer materials. Through experiments and calculations, we put forward a new emission layer for electron multipliers, including 2–3 nm Al2O3 buffer layer, 5–9 nm MgO main-body layer, 1 nm Al2O3 protective layer or 0.3 nm Al2O3 enhancement layer. We prepared this emission layer to microchannel plate (MCP), which significantly improved the gain of MCP. We can also apply this new emission layer to channel electron multiplier and separate electron multiplier.

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“…Full descriptions of Kelvin probe method operation can be found in [36][37][38]. Here we give the main principles of using the method for EE yield measurements, which were employed by Belhaj [39]. The insulating surface is irradiated with an electron pulse of a current density j.…”

Section: Indirect Methodsmentioning

confidence: 99%

Experimental investigation of electron emission from dielectric surfaces due to primary electron beam: a review

Chvyreva

Pemen

2014

IEEE Trans. Dielect. Electr. Insul.

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When charged particles impact the surface of a solid material, they can be backscattered from that surface or cause secondary electrons to be emitted. The ratio of the number of emitted electrons (secondary and backscattered) to the incident electrons number is known as the total electron emission yield. Knowledge of this total electron emission yield (TEEY) is highly required in various modern technologies, and several experimental techniques were developed with the purpose of its determination. However, experimental data, obtained with different methods are not in good agreement and sometimes are even contradictive. The purpose of this paper is to review the existing experimental methods of investigating electron emission (EE) from dielectric surfaces, as well as to analyze their accuracy and reliability. The focus is on the processes of the emission from thick layers of insulators which is the case for modern high voltage technologies.

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A Kelvin probe based method for measuring the electron emission yield of insulators and insulated conductors subjected to electron irradiation

Cited by 19 publications

References 29 publications

Electron-emission yield under electron impact of ceramics used as channel materials in Hall-effect thrusters

Electron-emission yield under electron impact of ceramics used as channel materials in Hall-effect thrusters

The Design of the Emission Layer for Electron Multipliers

Experimental investigation of electron emission from dielectric surfaces due to primary electron beam: a review

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