Dechanneling Effects in EELS and EDXS Analysis of Ybacu-Oxides

2001 ◽  
Vol 7 (S2) ◽  
pp. 340-341
Author(s):  
Peter Miller
Keyword(s):  
Quantitative Analysis ◽  
Energy Loss ◽  
Momentum Transfer ◽  
Crystal Orientation ◽  
Ionization Rate ◽  
X Rays ◽  
Electron Wave ◽  
X Ray ◽  
Factor Method ◽  
Specimen Orientation

Quantitative analysis in the TEM by EELS or EDXS depends on the K-factor method in which uniform ionization, independent of specimen orientation and thickness, is assumed. This assumption is of limited validity for crystals, where channeling of the electron wave ψ affects the ionization rate as observed in both energy loss and X-ray signals. Both EELS and EDXS are sensitive to changes in ψψ*near the atomic sites, and this variation as a function of crystal orientation forms the basis for ALCHEMI. Simultaneously recorded EELS and EDXS spectra were used to monitor changes in Cu/Ba ratio from YBaCu-oxides using L2,3/M4,5 ionization edges or K/L X-rays respectively. Although the acceptance aperture for EELS (11 mrad at 300 keV) may not be sufficiently large to mask double-channeling effects, it is small enough that momentum transfer is sufficiently limited to enhance derealization. Thus it is expected that the EELS signal should be less sensitive to crystal orientation than EDXS (an estimate of impact parameters yields 0.73 and 0.61 Å for the Ba and Cu energy loss signals, reducing to 0.06 and 0.04 Å respectively for X-ray emissions).

Comparison of high-angle take-off and low-angle take-off EDX detector geometry of the HF-2000 FE-TEM

1993 ◽  
Vol 51 ◽  
pp. 252-253
Author(s):  
Y. Sato ◽  
T. Hashimoto ◽  
M. Ichihashi ◽  
Y. Ueki ◽  
K. Hirose ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Field Emission ◽  
Solid Angle ◽  
Energy Dispersive ◽  
Objective Lens ◽  
X Rays ◽  
High Angle ◽  
X Ray ◽  
Detector Geometry

Analytical TEMs have two variations in x-ray detector geometry, high and low angle take off. The high take off angle is advantageous for accuracy of quantitative analysis, because the x rays are less absorbed when they go through the sample. The low take off angle geometry enables better sensitivity because of larger detector solid angle.Hitachi HF-2000 cold field emission TEM has two versions; high angle take off and low angle take off. The former allows an energy dispersive x-ray detector above the objective lens. The latter allows the detector beside the objective lens. The x-ray take off angle is 68° for the high take off angle with the specimen held at right angles to the beam, and 22° for the low angle take off. The solid angle is 0.037 sr for the high angle take off, and 0.12 sr for the low angle take off, using a 30 mm2 detector.

Small-angle scattering of X-rays in a conventional Bragg–Brentano diffractometer for quantitative analysis

1995 ◽  
Vol 10 (3) ◽  
pp. 170-172
Author(s):  
Stefano Battaglia
Keyword(s):  
Quantitative Analysis ◽  
Diffraction Analysis ◽  
Small Angle ◽  
Carbonate Rocks ◽  
International Standards ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Orientation Effects ◽  
Angle Scattering

A technique is presented utilizing an unmodified commercial X-ray diffractometer, equipped with a Bragg–Brentano geometry, for reducing preferred orientation effects in measured intensities during quantitative diffraction analysis. The diffractometer setup examined makes possible data acquisition with Θ fixed at 1° and 2Θ scanning the Bragg line. The results obtained with this technique are shown in the quantitative X-ray diffraction analysis of three international standards of carbonate rocks (401,402,403).

Quantitative analysis with a two-detector measuring system in in-air PIXE-design to improve detection sensitivity at low energies

2013 ◽  
Vol 23 (01n02) ◽  
pp. 55-67 ◽  
Author(s):  
K. Sera ◽  
S. Goto ◽  
C. Takahashi ◽  
Y. Saitoh
Keyword(s):  
Quantitative Analysis ◽  
Production Cross ◽  
Detection Sensitivity ◽  
Measuring System ◽  
X Rays ◽  
Standard Material ◽  
X Ray ◽  
New Device ◽  
Low Energies ◽  
Improve Detection Sensitivity

In this paper, a two-detector measuring system in in-air PIXE system composed of two Si(Li) detectors has been developed for simultaneous measurement of low- and high-Z elements. In order to improve detection sensitivity of the detector for low energy region, a new device which is attached at the tip of the detector has been designed. It is made of acryl and has a thin end on which a 1.5 μm-thick Mylar film is stuck. As a result, it exhibited a miraculous effect in improving detection sensitivity at low energies and it became possible to detect K X-rays of aluminium. In order to perform quantitative analysis in in-air system, we have measured detection efficiencies for the two Si(Li) detectors including the effect of X-ray absorption in air on the basis of the method that we developed. Concerning the beam energy at the target and corresponding X-ray production cross-sections, the same values as were reported in the previous paper were applicable since conditions of irradiating system were unchanged. It was confirmed that the new method allows us to quantitatively analyze all the elements heavier than aluminum and to obtain mostly the same results as those by in-vacuum PIXE for various kinds of samples. Accuracy of analysis was also confirmed by using a standard material.

PLATINUM GROUP ELEMENT HIGH-ENERGY PIXE

1990 ◽  
Vol 01 (02) ◽  
pp. 147-156 ◽  
Author(s):  
NORMAN M. HALDEN ◽  
FRANK C. HAWTHORNE ◽  
J.J. GUY DUROCHER ◽  
JASPER S.C. McKEE ◽  
ALI MIRZAI
Keyword(s):  
Quantitative Analysis ◽  
Proton Beam ◽  
Cross Section ◽  
Platinum Group Element ◽  
High Energy ◽  
Group Element ◽  
X Rays ◽  
Proton Bombardment ◽  
X Ray ◽  
Platinum Group

K X-ray spectra have been obtained from Platinum-Group Element (PGE) minerals using 40 MeV Proton-Induced X-ray Emission. It is possible to resolve all four component X-ray lines for the PGEs. In cases where there is more than one PGE present, some K X-ray lines may overlap, but in all cases, there were single lines available for quantitative analysis. The spectrum obtained from the sperrylite during exposure to the proton beam beam contained Au X-rays. The presence of the Au can be attributed to (p,xn) reactions with Pt, induced by proton bombardment of the sample. The intensity of Au X-ray lines in the spectrum is proportional to the amount of Pt in the sample and the cross-section for (p,xn) reactions between Pt and Au at 40 MeV.

Experimental Evaluation of Absolute X-RAY Intensities at Low to Moderate Beam Energies

1990 ◽  
Vol 48 (2) ◽  
pp. 12-13
Author(s):  
John T. Armstrong ◽  
Paul K. Carpenter
Keyword(s):  
Quantitative Analysis ◽  
Experimental Evaluation ◽  
Functional Relationship ◽  
X Rays ◽  
Detector Efficiency ◽  
X Ray ◽  
Characteristic Lines ◽  
Secondary Fluorescence ◽  
The Continuum

Knowledge of the absolute electron-induced production of the characteristic x-rays for different lines and elements is required for proper evaluation of the characteristic fluorescence correction or for development of “standardless” x-ray quantitative analysis correction procedures. Determination of absolute generated x-ray intensities in thick specimens or even relative generated x-ray intensities for lines of different elements in thick specimens is quite difficult as demonstrated by the lack of agreement of the published attempts to determine absolute generated x-ray intensity yields. The amount of absorption of the generated x-ray intensity in the sample and the amount of x-ray production from secondary fluorescence by other characteristic lines or by the continuum must be calculated. Moreover, the detector efficiency for measuring the different lines must be known. Most investigations of absolute generated x-ray intensities suggest that there is a functional relationship between the generated intensity and the overvoltage (U = Eo/Ec) at which the measurement is made.

scholarly journals Possible Contraction of the Members of the Binary Pulsar PSR 1913+16 and its Astrophysical Consequences

1983 ◽  
Vol 104 ◽  
pp. 431-436
Author(s):  
N. Spyrou
Keyword(s):  
Energy Loss ◽  
Small Difference ◽  
X Rays ◽  
Mass Energy ◽  
Contraction Rate ◽  
X Ray ◽  
Binary Pulsar ◽  
Contraction Phase ◽  
Slow Contraction ◽  
Absolute Luminosity

It is proposed that the small difference between the observed and the theoretically predicted decrease of the orbital period of the Binary Pulsar PSR 1913+16 is not due to the insufficiency of the quadrupole formula and can be attributed to a mass-energy loss due to the contraction of the binary's members. Assuming that the pair's primary is a typical, noncontracting pulsar, is in favour of a slowly contracting, neutron-star companion, thus limiting the member's radii to at most 25 km and 28 km, respectively. The primary's computed total absolute luminosity is in excellent agreement with the observed upper limit of its X-ray and optical luminosities. Moreover, the companion's slow contraction rate implies that its present total absolute luminosity presents a maximum at wavelengths characteristic of X-rays. Finally, it suggests that if the energy-loss remains constant, the duration of the contraction phase will be of the order of 108 y and the final radius about 25 km.

scholarly journals Integrated Electron and X-Ray Induced Microbeam XRF in the SEM

2004 ◽  
Vol 12 (4) ◽  
pp. 20-23 ◽  
Author(s):  
Brian J. Cross ◽  
Kenny C. Witherspoon
Keyword(s):  
Trace Elements ◽  
Electron Microscope ◽  
Quantitative Analysis ◽  
Compositional Analysis ◽  
X Rays ◽  
Complementary Information ◽  
Secondary Electrons ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Scanning Electron

Energy-Dispersive X-Ray Spectroscopy (ED-XRS or EDS) is a powerful and easy-to-use technique for the elemental analysis of a wide variety of materials. Most commonly, this technique is called X-Ray Fluorescence (XRF), which classically uses x-ray photon sources to excite the sample. A Scanning Electron Microscope (SEM), of course, uses electrons as the excitation source for microbeam x-ray spectroscopy together with sample imaging using characteristic x-rays and/or secondary electrons. These two XRS techniques are used independently, although often the same sample is analysed by both, to provide complementary information.The advantages of both techniques have been reviewed several times [e.g. 1,2], SEM-EDS being more suited to imaging and microbeam quantitative compositional analysis and maps, and XRF more suited to accurate quantitative analysis, especially for trace elements, while analyzing a much larger area.

Elemental Analysis of thin Films Using Inner Shell Electron Energy Losses

1976 ◽  
Vol 34 ◽  
pp. 414-415
Author(s):  
D. E. Johnson ◽  
M. Isaacson
Keyword(s):  
Thin Films ◽  
Energy Loss ◽  
Electron Energy ◽  
Elemental Analysis ◽  
Large Fraction ◽  
Fluorescence Yield ◽  
Detection Sensitivity ◽  
X Rays ◽  
X Ray ◽  
Electron Energy Loss

The use of electron energy loss spectroscopy (ELS) for elemental analysis of thin films holds considerable promise. This technique has definite advantages in comparison with energy dispersive X-ray spectroscopy (EDS) for two fundamental reasons. First, the detection sensitivity is independent of the fluorescence yield, since for each inner shell excitation an energy loss electron exists as opposed to only a finite probability that an excitation will result in a X-ray emitted. Second, the information carrying energy loss electrons are contained in a small solid angle about 0° scattering angle as opposed to the resulting X-rays which are emitted uniformly over 4Π steradians. This means that a large fraction of the energy loss electrons can be detected (up to ∼90%) compared to only a small fraction (∼1%) of the emitted X-rays with an EDS system.

PHYSICAL QUANTITATIVE ANALYSIS IN IN-AIR PIXE

2007 ◽  
Vol 17 (01n02) ◽  
pp. 1-10 ◽  
Author(s):  
K. SERA ◽  
K. TERASAKI ◽  
J. ITOH ◽  
Y. SAITOH ◽  
S. FUTATSUGAWA
Keyword(s):  
Quantitative Analysis ◽  
Cross Sections ◽  
Production Cross ◽  
Physical Method ◽  
Vacuum System ◽  
Physical Analysis ◽  
X Rays ◽  
Standard Samples ◽  
X Ray ◽  
Kapton Foil

A physical method of quantitative analysis for in-air PIXE has been established. Among the three parameters required for performing physical analysis, X-ray production cross sections were recalculated by using the effective energy of the proton beam after losing its energy through a Kapton foil and in air. Detection efficiencies of the Si ( Li ) detector have been determined according to our method established for in vacuum system, where effects of absorption of X-rays in air are incorporated into the detection efficiencies. As a result, it is confirmed that the present method gives us accurate results in the analyses of standard samples as well as actual samples such as soil and ash. It becomes possible to perform quantitative analysis of various samples by optimizing the measuring conditions depending on the samples.

Sign in / Sign up

Export Citation Format

Share Document