SU-FF-T-359: Primary Electron Beam Spot Parameter Determination for X-Ray Beams

2007 ◽  
Vol 34 (6Part13) ◽  
pp. 2484-2484
Author(s):  
D Sawkey ◽  
B Faddegon
Keyword(s):  
Electron Beam ◽  
Primary Electron ◽  
Parameter Determination ◽  
Primary Electron Beam ◽  
Beam Spot ◽  
X Ray

X-Ray Energy Dispersive Spectroscopy in the Environmental Scanning Electron Microscope

1998 ◽  
Vol 4 (S2) ◽  
pp. 182-183
Author(s):  
John F. Mansfield ◽  
Brett L. Pennington
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Energy Dispersive Spectroscopy ◽  
Primary Electron ◽  
Environmental Scanning ◽  
Primary Electron Beam ◽  
X Ray ◽  
Environmental Sem ◽  
Scanning Electron

The environmental scanning electron microscope (Environmental SEM) has proved to be a powerful tool in both materials science and the life sciences. Full characterization of materials in the environmental SEM often requires chemical analysis by X-ray energy dispersive spectroscopy (XEDS). However, the spatial resolution of the XEDS signal can be severely degraded by the gaseous environment in the sample chamber. At an operating pressure of 5Torr a significant fraction of the primary electron beam is scattered after it passes through the final pressure limiting aperture and before it strikes the sample. Bolon and Griffin have both published data that illustrates this effect very well. Bolon revealed that 45% of the primary electron beam was scattered by more than 25 μm in an Environmental SEM operating at an accelerating voltage of 30kV, with a water vapor pressure of 3Torr and a working distance of 15mm.

Effects of chamber pressure and accelerating voltage on X-RAY resolution in the ESEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1324-1325 ◽  
Author(s):  
Brendon J. Griffin
Keyword(s):  
Electron Beam ◽  
Primary Electron ◽  
Chamber Pressure ◽  
X Rays ◽  
Viewing Angle ◽  
Primary Electron Beam ◽  
Specific Data ◽  
X Ray ◽  
Working Distance ◽  
Eds Microanalysis

Chamber pressure, accelerating voltage and working distance have been shown to control the relative diameter of the scattered skirt of the primary electron beam at the specimen surface in the ESEM. Inital x-ray studies indicate that at 3 torr, 30 kV and a WD=15mm, 45% of the beam comes from beyond 25 μm of the incidence point and 4% from beyond 1.5mm. At 5 torr 66% of the beam is scattered beyond 25 μm2. No specific data was available on the spatial resolution of x rays and this study aimed to improve that situation. The results also form the basis for establishing a mechanism for and defining the potential limits of quantitative EDS microanalysis in the ESEM.The negative viewing angle of the EDS x-ray detector in the current ESEM (model E-3) requires at least a 15 degree tilt on a flat sample for microanalysis. This geometry places a narrow limit on the working distance range that can be used, due to the collimation of the detector, thereby effectively eliminating working distance as a variable in x-ray microanalysis.

Quantitative EDS analysis in the environmental ESEM using a bremstrahlung intensity-based correction for primary electron beam variation and scatter

1996 ◽  
Vol 54 ◽  
pp. 842-843 ◽  
Author(s):  
B.J. Griffin ◽  
C.E. Nockolds
Keyword(s):  
Electron Beam ◽  
Beam Current ◽  
Primary Electron ◽  
Primary Beam ◽  
Minimum Condition ◽  
Chamber Pressure ◽  
Primary Electron Beam ◽  
Faraday Cage ◽  
X Ray ◽  
Eds Analysis

Quantitative EDS analysis of bulk samples in the scanning electron microscope (SEM) or electron microprobe requires, as a fundamental parameter, a stable and reproducible primary electron beam current Beam current is usually measured with a Faraday cage positioned in the electron column below the objective aperture or in the specimen holder. Reproducibility and stability within 1%/hour is a minimum condition.Primary beam current measurement in the ESEM or any high pressure SEM is difficult to measure. Electron-gas interaction in the biased chamber generates a positive ion flow highly amplified relative to the primary beam (Danilatos, 1990) and generates an x-ray signal from the gas. The latter signal amplitude is dependent on primary beam current, chamber pressure and backscatter electron signal from the specimen (Griffin et al. 1993). These interactions prevent quantification of EDS data standardised to Faraday cage primary beam current measurements or x-ray counts from a reference standard.

The measurement of the fluorescence of Si K x-rays by Au M x-rays

1990 ◽  
Vol 48 (2) ◽  
pp. 198-199
Author(s):  
John A. Small ◽  
Scott A. Wight ◽  
Robert L. Myklebust ◽  
Dale E. Newbury
Keyword(s):  
Electron Beam ◽  
Electron Probe ◽  
Primary Electron ◽  
Characteristic Line ◽  
X Rays ◽  
Limited Information ◽  
Primary Electron Beam ◽  
X Ray ◽  
Image Position ◽  
Critical Excitation

The characteristic fluorescence correction is used in electron probe microanalysis to account for the x-ray intensity excited in element “a” by the x-rays from the characteristic line of another element, “b”, in the sample. Since the excited intensity is not generated by the primary electron beam, it is necessary to apply the fluorescence correction for quantitative elemental analysis. This correction can be significant particularly when element “b” is a major component of the sample and the characteristic line for element “b” is slightly higher in energy than the critical excitation energy for the excited line of element “a”.The fluorescence correction, which is used in the various analytical programs, is described in equation 1.where I'*fa/I'*pa is the ratio of the emitted “a” intensity excited by “b” x-rays to the emitted intensity excited by the primary electron beam. The various parameters in this equation are accurately known for the K x-ray lines, but only very limited information is available for the M x-ray lines.

scholarly journals OPERATION OF AN INDUSTRIAL ELECTRON ACCELERATOR IN A DOUBLE-BEAM e,X-MODE

2019 ◽  
pp. 163-167
Author(s):  
V.A. Shevchenko ◽  
A.Eh. Tenishev ◽  
V.L. Uvarov ◽  
A.A. Zakharchenko
Keyword(s):  
Electron Beam ◽  
Electron Accelerator ◽  
Primary Electron ◽  
Primary Electron Beam ◽  
Object Processing ◽  
X Ray ◽  
Double Beam ◽  
Industrial Accelerator ◽  
Radiation Channel ◽  
Good Agreement

Analysis of mixed e,X-radiation formation in output devices of an industrial electron accelerator is conducted. The possibility is demonstrated to obtain an extra radiation channel on the basis of a practically free source of Xrays simultaneously with the main channel of product processing with electron beam. The conditions of production of the secondary radiation in the state of electronic equilibrium at product treatment with scanning electron beam in the main radiation channel are studied by means of computer simulation. The dependence of spatial radiant characteristics of the X-ray radiation on the spectrum of a primary electron beam and surface density of a treated load has been established. For an industrial accelerator LU-10 of NSC KIPT, the regime of object processing in the extra radiation channel is examined. The results of calculation of the X-ray dose rate and its spatial distribution are in good agreement with the experimental data. The comparative capacity of both radiation channels of the plant is analyzed. The extra radiation source can be used for the execution of non-commercial programs like sanitation of cultural artefacts.

Electron Beam Degradation of Sulfide-Based Thin-Film Phosphors for Field Emission Flat Panel Displays

1998 ◽  
Vol 508 ◽  
Author(s):  
B.L. Abrams ◽  
T.A. Trottier ◽  
H.C. Swart ◽  
E. Lambers ◽  
P.H. Holloway
Keyword(s):  
Thin Film ◽  
Electron Beam ◽  
Surface Chemistry ◽  
Threshold Voltage ◽  
Degradation Process ◽  
Primary Electron ◽  
Flat Panel Displays ◽  
Primary Electron Beam ◽  
Atomic Species ◽  
Gas Pressures

AbstractThe change in cathodoluminescence (CL) brightness and changes in surface chemistry of the thin film phosphor, SrS:Ce, have been investigated using a scanning Auger electron spectrometer and an Oriel optical spectrometer. The data for SrS:Ce were compared to ZnS:Cu, Al, Au and Y2O2S:Eu powders all collected in a stainless steel UHV chamber with gas pressures of 10−6 Torr O2. In the presence of a 2kV primary electron beam, the amounts of C and S on the surface decreased while the oxygen concentration increased. As a result, ZnO, Y2O3 and presumably SrOx formed. This change in surface chemistry coincided with a decrease in CL brightness. SrS degraded much faster than ZnS or Y2O2S. The model for this degradation process suggests that the primary electron beam dissociated physisorbed molecules to reactive atomic species. These atomic species reacted with surface S and C, carrying them away and leaving behind an increasingly more impenetrable layer. Threshold voltage experiments were conducted to reveal where it becomes possible to measure the CL. This threshold voltage should be affected by the oxide layer discussed above. The implications for vacuums in an FED FPD will be discussed.

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