Application of WFS for Simultaneous Work Function and Secondary Electron Emission Measurement on Ba Covered Tungsten

2005 ◽  
Vol 473-474 ◽  
pp. 293-296
Author(s):  
György Vida ◽  
Ildikó Beck ◽  
V. Katalin Josepovits ◽  
Miklós Győr
Keyword(s):  
Work Function ◽  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Secondary Emission ◽  
Operating Conditions ◽  
Emission Measurement ◽  
Pressure Discharge ◽  
Emission Yield ◽  
Burning Voltage

In the present paper the secondary emission and work function of W covered with different thickness Ba layers are compared. The secondary emission and work function were measured by Work Function Spectroscopy (WFS). It is clearly pointed out that the thin Ba coating causes the the enhancement of electron induced secondary electron emission. In high pressure discharge lamps high secondary emission and high thermionic current are required for reliable operating conditions, i.e., for reaching the nominal burning voltage and current etc. The results prove that the Ba spreading on the W surface from an alkali earth tungstate material is advantageous for lowering the work function and, simultaneously, for increasing the secondary emission yield.

scholarly journals Dynamic secondary electron emission in rough composite materials

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Leandro Olano ◽  
Maria E. Dávila ◽  
John R. Dennison ◽  
Petronilo Martín-Iglesias ◽  
Isabel Montero
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Surface Profile ◽  
Secondary Emission ◽  
Technological Problem ◽  
Vacuum Technology ◽  
3D Geometry ◽  
Emission Yield ◽  
Continuous Equation

Abstract The interaction of ionizing radiation with matter is of critical importance in numerous areas of science and technology like space and vacuum technology and even medicine and biotechnology. Secondary electron emission is a consequence of electron irradiation on materials. We achieve extremely low secondary electron emission yield values smaller than 0.2, even up to incident electron energies ~1 keV, due to an undocumented synergy between neighbouring metal and dielectric domains in composite samples. To investigate this experimental discovery, we propose a simple 3D model where the dielectric and metallic domains are arranged in parallel and interleaved. The proposed surface profile has a triangular shape to model the surface roughness. We obtain a continuous equation to describe the electric field that arises between grounded conductors and charged dielectrics domains. The calculated trajectories of secondary electrons in this 3D geometry are used to predict dynamic secondary emission yield, which strongly depends on the charge accumulated in the dielectric domains. This research paves the way to design new materials of low secondary emission yield, addressing the technological problem not yet resolved to inhibit the electron avalanche in RF equipment that limit their maximum working power.

scholarly journals Secondary electron emission measurement from Cr and Cu bombarded by an Ne10+ beam at 6 MeV/n

2020 ◽  
Vol 2020 (3) ◽  
Author(s):  
A Higashi ◽  
Y Hashimoto ◽  
D Ohsawa ◽  
T Shirai ◽  
K Noda
Keyword(s):  
Fermi Level ◽  
Electron Emission ◽  
Secondary Electron ◽  
Small Difference ◽  
Secondary Electron Emission ◽  
Stopping Power ◽  
Emission Measurement ◽  
Electron Density Of States ◽  
Emission Yield ◽  
Conduction Electron Density

Abstract Backward secondary-electron-emission yield ($\delta$) from plates of 0.1 mm-thick Cu and 1 mm Cr and Al have been measured by irradiation of a fully stripped Ne$^{10+}$ beam at 6 MeV/$n$ stopped within each plate. A difference between $\delta$s from Cr and Cu larger than the ambiguity of this measurement ($\pm$3%) has been observed, with the discrepancy of the predicted small difference by kinetic emission based on stopping power and work function of each metal. The measured $\delta$ from Cr is larger than that from Cu, and also than previous measurements of other transition metals of the 3$d$ series, not only for the process of potential emission but also for kinetic. The conduction-electron density of states around the Fermi level calculated for the metals shows that the number of electrons just below the Fermi level and excited over it to an empty level by many kinds of reaction with the beam irradiation has to be considered. The number involved in this emission from Cr thus seems to be much larger than from Cu, which explains the relation of magnitudes for $\delta$. The measured $\delta$ from Al is larger than previous results, but is still consistent due to the existence of Al$_2$O$_3$ on the Al.

Historical Introduction

1977 ◽  
Vol 35 ◽  
pp. 2-5
Author(s):  
R. D. Heidenreich
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
50Th Anniversary ◽  
Secondary Emission ◽  
Wave Nature ◽  
Nobel Prize In Physics ◽  
Primary Electrons ◽  
The U.S ◽  
Mutual Agreement

This program has been organized by the EMSA to commensurate the 50th anniversary of the experimental verification of the wave nature of the electron. Davisson and Germer in the U.S. and Thomson and Reid in Britian accomplished this at about the same time. Their findings were published in Nature in 1927 by mutual agreement since their independent efforts had led to the same conclusion at about the same time. In 1937 Davisson and Thomson shared the Nobel Prize in physics for demonstrating the wave nature of the electron deduced in 1924 by Louis de Broglie.The Davisson experiments (1921-1927) were concerned with the angular distribution of secondary electron emission from nickel surfaces produced by 150 volt primary electrons. The motivation was the effect of secondary emission on the characteristics of vacuum tubes but significant deviations from the results expected for a corpuscular electron led to a diffraction interpretation suggested by Elasser in 1925.

scholarly journals Atypical secondary electron emission yield curves of very thin SiO2 layers: Experiments and modeling

2021 ◽  
Vol 130 (13) ◽  
pp. 135305
Author(s):  
C. Rigoudy ◽  
K. Makasheva ◽  
M. Belhaj ◽  
S. Dadouch ◽  
G. Teyssedre ◽  
...  
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Yield Curves ◽  
Emission Yield
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