Recent Developments in Txrf of Light Elements

1995 ◽  
Vol 39 ◽  
pp. 771-779 ◽  
Author(s):  
Christina Streli ◽  
V. Bauer ◽  
P. Wobrauschek
Keyword(s):  
Absorption Edge ◽  
Detection Efficiency ◽  
Fluorescence Analysis ◽  
Total Reflection ◽  
Low Energy ◽  
X Rays ◽  
Light Elements ◽  
Energy Dispersive Analysis ◽  
X Ray ◽  
Recent Developments

Total Reflection X-ray Fluorescence Analysis (TXRF) has been proved to be well suited for the energy dispersive analysis of light elements, as B, C, N, O, F, Na, Mg,.,. using a special spectrometer. It is equipped with a Ge(HP) detector offering a sufficient detection efficiency from 180 eV upwards. The obtainable detection limits especially of the light elements are mainly influenced by the excitation source, which should provide a large number of photons with an energy near the K-absorption edge of these elements (from 200 eV upwards). Commercially available X-ray tubes do not offer characteristic X-rays in that range. In former experiments a windowless X-ray tube was built to prevent the low energy X-rays from being attenuated in the Be window. Experiments have been performed using Cu as anode material.

Measurements of Soft and Ultrasoft X-Rays with Total Reflection Monochromator

1986 ◽  
Vol 30 ◽  
pp. 213-223
Author(s):  
Tomoya Arai
Keyword(s):  
Gas Flow ◽  
Bragg Reflection ◽  
Optical Resolution ◽  
Fluorescence Analysis ◽  
Total Reflection ◽  
X Rays ◽  
Light Elements ◽  
Lower Intensity ◽  
Measured Intensity ◽  
X Ray

The development of X-ray spectrographic analysis of light elements, which are O, C and B, has bee n performed for many applications using an end-window type X-ray tube with Rh-target and thin Be-window, wavelength dispersing devices, which are synthetic multilayers or total reflection mirror (with a specific filter) and a gas flow proportional counter with a thin film window. In Fig. 1 factors related to the intensity measurements in X-ray fluorescence analysis are shown. The excitation efficiency in the soft and ultrasoft X-ray region is very low because of the lower intensity of primary X-rays and low fluorescence yield of light elements. Instead of the wavelength dispersive method of Bragg reflection, having high resolution and low reflectivity, monochromatization combining total reflection by a selected mirror and an appropriate filter offered an alternate approach in order to increase measured intensity with reasonable optical resolution. Synthetic multilayers which have higher resolution and lower intensity compared with the performance of the mirror method have become popular for the detection of soft and ultrasoft X-ray region.

Total Reflection Xrf of Light Elements Using Various Excitation Sources

1993 ◽  
Vol 37 ◽  
pp. 577-583
Author(s):  
Christina Streli ◽  
P. Wobrauschek ◽  
H. Aiginger ◽  
W. Ladisich ◽  
R. Rieder
Keyword(s):  
Synchrotron Radiation ◽  
Fluorescence Analysis ◽  
Total Reflection ◽  
Low Energy ◽  
Energy Dispersive ◽  
Total Power ◽  
Light Elements ◽  
X Ray ◽  
Reflection Geometry ◽  
Excitation Conditions

AbstractTotal Reflection X-Ray Fluorescence Analysis (TXRF) has been proved to be well suited for the energy dispersive analysis of light elements using a special spectrometer, which is equipped with an energy dispersive detector having all properties for the detection of low energy radiation. The detection of the light elements is strongly influenced by the excitation source which should provide a large number of photons with energies near the K-absorption edge of these elements (0.2 - 3 keV). Various standard tubes with Be-window as well as a homemade windowless tube are compared, all differing in focal size, total power and anode material. Optimized excitation conditions are provided by synchrotron radiation meeting all requirements for excellent excitation of light elements in total reflection geometry such as high brilliance and ideal spectral distribution specially in the low energy region. A comparison of excitation with X-ray tubes as well as with synchrotron radiation is shown. Detection limits of 200 fg for Mg have been obtained with synchrotron radiation.

How to Use the Features of Total Reflection of X-Rays for Energy Dispersive XRF

1988 ◽  
Vol 32 ◽  
pp. 105-114 ◽  
Author(s):  
H. Schwenke ◽  
W. Berneike ◽  
J. Knoth ◽  
U. Weisbrod
Keyword(s):  
Thin Films ◽  
Penetration Depth ◽  
Fluorescence Analysis ◽  
Total Reflection ◽  
X Rays ◽  
X Ray ◽  
Characteristic Features ◽  
Respective Characteristic ◽  
Nanometer Regime ◽  
Sensitive Method

AbstractThe total reflection of X-rays is mainly determined by three parameters , that is the orltical angle, the reflectivity and the penetration depth. For X-ray fluorescence analysis the respective characteristic features can be exploited in two rather different fields of application. In the analysis of trace elements in samples placed as thin films on optical flats, detection limits as low as 2 pg or 0.05 ppb, respectively, have been obtained. In addition, a penetration depth in the nanometer regime renders Total Reflection XRF an inherently sensitive method for the elemental analysis of surfaces. This paper outlines the main physical and constructional parameters for instrumental design and quantitation in both branches of TXRF.

Total reflection x-ray fluorescence analysis of light elements under various excitation conditions

1995 ◽  
Vol 24 (3) ◽  
pp. 137-142 ◽  
Author(s):  
C. Streli ◽  
P. Wobrauschek ◽  
W. Ladisch ◽  
R. Rieder ◽  
H. Aiginger
Keyword(s):  
Fluorescence Analysis ◽  
Total Reflection ◽  
Light Elements ◽  
X Ray ◽  
Excitation Conditions

X-Ray Fluorescence Analysis at Room Temperature with an Energy Dispersive Mercuric Iodide Spectrometer

1979 ◽  
Vol 23 ◽  
pp. 249-256
Author(s):  
M. Singh ◽  
A.J. Dabrowski ◽  
G.C. Huth ◽  
J.S. Iwanczyk ◽  
B.C. Clark ◽  
...  
Keyword(s):  
Room Temperature ◽  
Fluorescence Analysis ◽  
Low Energy ◽  
Cryogenic Cooling ◽  
Energy Dispersive ◽  
Entrance Window ◽  
X Rays ◽  
Mercuric Iodide ◽  
X Ray ◽  
Present Design

We have previously reported on the uniqueness and potential of room-temperature spectrometry of low-energy x-rays with a mercuric iodide (HgI2) detector (1,2,3). In this paper we emphasize the use of HgI2 detectors for x-ray fluorescence (XRF) analysis.Because no vacuum plumbing or cryogenic cooling is required, the design of a mercuric iodide room-temperature x-ray spectrometer is extremely simple. Our present design consists of coupling a detector directly to the first-stage FET in a modified Tennelec 161 D preamplifier and making the configuration “light-tight”. Aside from providing a suitable entrance window, there are no other requirements for routine spectroscopy.

Txrf-Sources-Samples and Detectors

1995 ◽  
Vol 39 ◽  
pp. 755-766
Author(s):  
P. Wobrauschek ◽  
P. Kregsamer ◽  
W. Ladisich ◽  
R. Riede ◽  
Christina Streli ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Detection Limits ◽  
Fluorescence Analysis ◽  
Total Reflection ◽  
Light Elements ◽  
X Ray

Total reflection x-ray fluorescence analysis (TXRF) has reached a mature state but still improvements are possible in selecting the proper components for TXRF and optimizing them in the best suitable way. Two approaches are presented, the extension of the number of detectable elements after K-shell excitation and the improvement of the detection limits. The results show, that the elements from B to U can be detected by their characteristic K-lines and that detection limits for medium Z elements e.g. Ni in the fg range are achievable. Most of the best results have been measured using synchrotron radiation with spectral modifying devices like multilayer monochromators. Other x-ray sources like a windowless tube with exchangeable anodes of either material Al, Si or Mo were successfully tested for the efficient excitation of light elements.

Recent Developments and Results in Total Reflection X-Ray Fluorescence Analysis

1991 ◽  
pp. 1-12 ◽  
Author(s):  
Peter Wobrauschek ◽  
Peter Kregsamer ◽  
Christina Streli ◽  
Hannes Aiginger
Keyword(s):  
Fluorescence Analysis ◽  
Total Reflection ◽  
X Ray ◽  
Recent Developments

Energy Dispersive X-ray Fluorescence Analysis Using Synchroton Radiation

1984 ◽  
Vol 28 ◽  
pp. 61-68 ◽  
Author(s):  
Atsuo Iida ◽  
Yohichi Gohshi ◽  
Tadashi Matsushita
Keyword(s):  
Fluorescence Analysis ◽  
Total Reflection ◽  
Energy Dispersive ◽  
High Signal ◽  
X Rays ◽  
X Ray ◽  
Background Ratio ◽  
Fluorescence Measurements ◽  
Sample Support ◽  
The Continuum

AbstractTrace element analyses by energy dispersive X-ray fluorescence measurements were made using synchrotron radiation from a dedicated electron storage ring at the Photon Factory in Japan. The continuum or the monochromatic beam was used for excitation. A crystal monochromator or two types of mirror systems were used for monochromatic excitation. A high signal to background ratio was attained with the crystal monochromator, while the highest absolute detectability was achieved with the mirror system. The minimum detection limita obtained from thin samples are of the order of 0.1 ppm or less than 0.1 pg. Furthermore the signal to background ratio was significantly improved by using an X-ray mirror as a sample support in which, external total reflection of exciting X-rays occured.

Light Element Analysis with TXRF

1991 ◽  
Vol 35 (B) ◽  
pp. 947-952
Author(s):  
Christina Streli ◽  
Peter Wobrauschek ◽  
Hannes Aiginger
Keyword(s):  
Trace Element Analysis ◽  
Light Element ◽  
Fluorescence Analysis ◽  
Analytical Tool ◽  
Total Reflection ◽  
Light Elements ◽  
Element Analysis ◽  
X Ray ◽  
Background Reduction ◽  
Powerful Analytical Tool

AbstractTotal Reflection X-Ray Fluorescence Analysis (TXRF) has become a powerful analytical tool for trace element analysis. Because of its advantages in excitation and background reduction TXRF has been applied for the analysis of light elements (C,O,F,Na,...). A special Ge(HP) detector offering an ultra thin window in combination with a spectrometer specially designed for the requirements of light element analysis was used. Also a new windowless X-ray tube for efficient excitation of the light elements was tested. The system was checked with standard aqueous solutions; detection limits in the ng range (7 ng for O) are obtained.

Total reflection X-ray fluorescence analysis of light elements with synchrotron radiation and special X-ray tubes

1997 ◽  
Vol 52 (7) ◽  
pp. 861-872 ◽  
Author(s):  
Christina Streli ◽  
P Wobrauschek ◽  
V Bauer ◽  
P Kregsamer ◽  
R Görgl ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Fluorescence Analysis ◽  
Total Reflection ◽  
Light Elements ◽  
X Ray
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