scholarly journals Multilateral surface analysis of the CeB6 electron-gun cathode used at SACLA XFEL

2021 ◽  
Vol 28 (6) ◽  
Author(s):  
Takuo Ohkochi ◽  
Takayuki Muro ◽  
Eiji Ikenaga ◽  
Kazuaki Togawa ◽  
Akira Yasui ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Central Area ◽  
Thermionic Emission ◽  
Electron Gun ◽  
X Ray ◽  
Laser Facility ◽  
Cathode Lens ◽  
Low Energy Electron ◽  
Photoemission Electron ◽  
Low Emittance

The CeB6(001) single crystal used as a cathode in a low-emittance electron gun and operated at the free-electron laser facility SACLA was investigated using cathode lens electron microscopy combined with X-ray spectroscopy at SPring-8 synchrotron radiation facility. Multilateral analysis using thermionic emission electron microscopy, low-energy electron microscopy, ultraviolet and X-ray photoemission electron microscopy and hard X-ray photoemission spectroscopy revealed that the thermionic electrons are emitted strongly and evenly from the CeB6 surface after pre-activation treatment (annealing at 1500°C for >1 h) and that the thermionic emission intensity as well as elemental composition vary between the central area and the edge of the old CeB6 surface.

Surface Reactions of Metal Catalysts for Carbon Nanotubes on an Oxide Thin Layer/Si Substrates Studied by in-situ Micro X-ray Adsorption Spectroscopy using SPELEEM

2006 ◽  
Vol 967 ◽  
Author(s):  
Fumihiko Maeda ◽  
Hiroki Hibino ◽  
Satoru Suzuki ◽  
FangZhun Guo ◽  
Yoshio Watanabe
Keyword(s):  
Electron Microscopy ◽  
Oxide Layer ◽  
X Ray ◽  
Si Substrates ◽  
Microscopy Image ◽  
Special Surface ◽  
Void Area ◽  
Low Energy Electron ◽  
Photoemission Electron

ABSTRACTTo clarify the reaction process of Co and Fe with a oxide layer on Si substrates, the annealing processes were analyzed using spectroscopic photoemission and low-energy electron microscopy for a special surface where oxide areas and clean substrate areas (voids) coexist closely in a micrometer-order view. From analyses of XAS spectra and edge jump ratios obtained from the photoemission electron microscopy image, we clarified that Co atoms in the void area remain because of the formation of silicides, but that those on the oxide layer disappear because metallic Co atoms easily diffuse. In contrast, in the case of Fe, we found the formation of various silicides and their gradual diffusion into Si substrate even in the form of silicides.

scholarly journals Quantification of propagating and standing surface acoustic waves by stroboscopic X-ray photoemission electron microscopy

2019 ◽  
Vol 26 (1) ◽  
pp. 184-193 ◽  
Author(s):  
Michael Foerster ◽  
Nahuel Statuto ◽  
Blai Casals ◽  
Alberto Hernández-Mínguez ◽  
Simone Finizio ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Chemical Properties ◽  
Photoemission Electron Microscopy ◽  
X Ray ◽  
Contrast Mechanism ◽  
Low Energy Electron ◽  
Photoemission Electron ◽  
And Chemical Properties

The quantification of surface acoustic waves (SAWs) in LiNbO3 piezoelectric crystals by stroboscopic X-ray photoemission electron microscopy (XPEEM), with a temporal smearing below 80 ps and a spatial resolution below 100 nm, is reported. The contrast mechanism is the varying piezoelectric surface potential associated with the SAW phase. Thus, kinetic energy spectra of photoemitted secondary electrons measure directly the SAW electrical amplitude and allow for the quantification of the associated strain. The stroboscopic imaging combined with a deliberate detuning allows resolving and quantifying the respective standing and propagating components of SAWs from a superposition of waves. Furthermore, standing-wave components can also be imaged by low-energy electron microscopy (LEEM). Our method opens the door to studies that quantitatively correlate SAWs excitation with a variety of sample electronic, magnetic and chemical properties.

In situ magnetic and electronic investigation of the early stage oxidation of Fe nanoparticles using X-ray photo-emission electron microscopy

2014 ◽  
Vol 16 (48) ◽  
pp. 26624-26630 ◽  
Author(s):  
C. A. F. Vaz ◽  
A. Balan ◽  
F. Nolting ◽  
A. Kleibert
Keyword(s):  
Electron Microscopy ◽  
Chemical Composition ◽  
Iron Nanoparticles ◽  
Early Stage ◽  
Photoemission Electron Microscopy ◽  
X Ray ◽  
Emission Electron ◽  
Fe Nanoparticles ◽  
Photoemission Electron

In situX-ray photoemission electron microscopy reveals the evolution of chemical composition and magnetism of individual iron nanoparticles during oxidation.

scholarly journals The EIGER detector for low-energy electron microscopy and photoemission electron microscopy

2017 ◽  
Vol 24 (5) ◽  
pp. 963-974 ◽  
Author(s):  
G. Tinti ◽  
H. Marchetto ◽  
C. A. F. Vaz ◽  
A. Kleibert ◽  
M. Andrä ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Dynamic Range ◽  
Single Photon ◽  
Low Energy ◽  
Energy Electron ◽  
Frame Rate ◽  
Pixel Detector ◽  
Photoemission Electron Microscopy ◽  
Low Energy Electron ◽  
Photoemission Electron

EIGER is a single-photon-counting hybrid pixel detector developed at the Paul Scherrer Institut, Switzerland. It is designed for applications at synchrotron light sources with photon energies above 5 keV. Features of EIGER include a small pixel size (75 µm × 75 µm), a high frame rate (up to 23 kHz), a small dead-time between frames (down to 3 µs) and a dynamic range up to 32-bit. In this article, the use of EIGER as a detector for electrons in low-energy electron microscopy (LEEM) and photoemission electron microscopy (PEEM) is reported. It is demonstrated that, with only a minimal modification to the sensitive part of the detector, EIGER is able to detect electrons emitted or reflected by the sample and accelerated to 8–20 keV. The imaging capabilities are shown to be superior to the standard microchannel plate detector for these types of applications. This is due to the much higher signal-to-noise ratio, better homogeneity and improved dynamic range. In addition, the operation of the EIGER detector is not affected by radiation damage from electrons in the present energy range and guarantees more stable performance over time. To benchmark the detector capabilities, LEEM experiments are performed on selected surfaces and the magnetic and electronic properties of individual iron nanoparticles with sizes ranging from 8 to 22 nm are detected using the PEEM endstation at the Surface/Interface Microscopy (SIM) beamline of the Swiss Light Source.

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