scholarly journals Light yield of scintillating nanocrystals under X-ray and electron excitation

2019 ◽  
Vol 215 ◽  
pp. 116613 ◽  
Author(s):  
R.M. Turtos ◽  
S. Gundacker ◽  
S. Omelkov ◽  
E. Auffray ◽  
P. Lecoq
Keyword(s):  
Light Yield ◽  
Electron Excitation ◽  
X Ray

Influence of X-Ray Induced Fluorescence on Energy Dispersive X-Ray Analysis of Thin Foils

1977 ◽  
Vol 35 ◽  
pp. 328-329
Author(s):  
E. A. Kenik ◽  
J. Bentley
Keyword(s):  
Thin Foil ◽  
Electron Excitation ◽  
Simple Approach ◽  
Foil Thickness ◽  
X Rays ◽  
X Ray ◽  
Hole Spectrum ◽  
Illumination System ◽  
Thin Foils ◽  
Intensity Ratios

Cliff and Lorimer (1) have proposed a simple approach to thin foil x-ray analy sis based on the ratio of x-ray peak intensities. However, there are several experimental pitfalls which must be recognized in obtaining the desired x-ray intensities. Undesirable x-ray induced fluorescence of the specimen can result from various mechanisms and leads to x-ray intensities not characteristic of electron excitation and further results in incorrect intensity ratios.In measuring the x-ray intensity ratio for NiAl as a function of foil thickness, Zaluzec and Fraser (2) found the ratio was not constant for thicknesses where absorption could be neglected. They demonstrated that this effect originated from x-ray induced fluorescence by blocking the beam with lead foil. The primary x-rays arise in the illumination system and result in varying intensity ratios and a finite x-ray spectrum even when the specimen is not intercepting the electron beam, an ‘in-hole’ spectrum. We have developed a second technique for detecting x-ray induced fluorescence based on the magnitude of the ‘in-hole’ spectrum with different filament emission currents and condenser apertures.

EXELFS Studies of Carbon Fibers

1990 ◽  
Vol 48 (2) ◽  
pp. 72-73
Author(s):  
V. Serin ◽  
K. Hssein ◽  
G. Zanchi ◽  
J. Sévely
Keyword(s):  
Carbon Fibers ◽  
Energy Analysis ◽  
Electron Excitation ◽  
Complex Structures ◽  
High Modulus ◽  
Promising Technique ◽  
X Ray ◽  
Fine Structures ◽  
X Ray Absorption

The present developments of electron energy analysis in the microscopes by E.E.L.S. allow an accurate recording of the spectra and of their different complex structures associated with the inner shell electron excitation by the incident electrons (1). Among these structures, the Extended Energy Loss Fine Structures (EXELFS) are of particular interest. They are equivalent to the well known EXAFS oscillations in X-ray absorption spectroscopy. Due to the EELS characteristic, the Fourier analysis of EXELFS oscillations appears as a promising technique for the characterization of composite materials, the major constituents of which are low Z elements. Using EXELFS, we have developed a microstructural study of carbon fibers. This analysis concerns the carbon K edge, which appears in the spectra at 285 eV. The purpose of the paper is to compare the local short range order, determined by this way in the case of Courtauld HTS and P100 ex-polyacrylonitrile carbon fibers, which are high tensile strength (HTS) and high modulus (HM) fibers respectively.

Fundamentals of X-ray Spectrometric Analysis Using Low-Energy Electron Excitation

1990 ◽  
Vol 34 ◽  
pp. 105-121 ◽  
Author(s):  
K. J. Romand ◽  
F. Gaillard ◽  
M. Charbonnier ◽  
D. S. Urch
Keyword(s):  
Analytical Techniques ◽  
Atomic Layer ◽  
Mean Free Path ◽  
Electron Excitation ◽  
Spectrometric Analysis ◽  
Ion Scattering ◽  
X Ray ◽  
Secondary Ions ◽  
Information Depth ◽  
Wide Range

In the field of material analysis and characterization interest has considerably shifted over the last few decades from bulk to surface and very thin film problems. At the present state a wide range of surface analytical techniques - such as x-ray photoelectron (XPS), Auger electron (AES), secondary ion mass (SIMS), ion scattering (ISS) spectroscopies - have become available but every one of them exhibits specific analytical features and information content. Within the context of this paper the main parameter to be considered is the information depth i.e the layer thickness from which the majority of information-bearing particles escape and hence are detected. For XPS and AES, this parameter is associated with the mean-free path of photoelectrans or Auger electrons and typically is in the range from 0.5 to 4 nm. In SIMS the ejected secondary ions are emitted from the outer 2 or 3 atomic layers (i.e. from about 1 nm) while the single-collision binary process occuring in ISS is restricted to atoms from the top most atomic layer (0.2-0.3 nm).

scholarly journals Growth and Scintillation Properties of Directionally Solidified Ce:LaBr3/AEBr2 (AE = Mg, Ca, Sr, Ba) Eutectic System

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 584 ◽  
Author(s):  
Kyoung Jin Kim ◽  
Yuki Furuya ◽  
Kei Kamada ◽  
Rikito Murakami ◽  
Vladimir V. Kochurikhin ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Decay Time ◽  
Gamma Ray ◽  
Light Yield ◽  
Fiber Bundles ◽  
Eutectic System ◽  
Directionally Solidified ◽  
X Ray ◽  
Scintillation Decay Time ◽  
Ionic Size

Ce-doped LaBr3/AEBr2 (AE = Mg, Ca, Sr, Ba) eutectics were grown using the Bridgman–Stockbarger (BS) method in quartz ampoules. The eutectics (AE = Mg and Ca) showed optical transparency like optical fiber bundles. A grown Ce-doped LaBr3/MgBr2 eutectic shows a 355 nm emission ascribed to Ce3+ 4f-5d transition under X-ray excitation. The smaller the ionic size of AE, the higher the light yield of the sample was. The light yield of Ce:LaBr3/MgBr2 was 34,300 photon/MeV, which is higher than Ce:LYSO standard. Scintillation decay time under 662 keV gamma-ray excitation was 18.8 ns.

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