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.

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.

scholarly journals Wavelength Dispersing Devices for Soft and Ultrasoft X-ray Spectrometers

1984 ◽  
Vol 28 ◽  
pp. 137-144 ◽  
Author(s):  
Tomoya Arai ◽  
Takashi Shoji ◽  
Richard W. Ryon
Keyword(s):  
Single Crystals ◽  
Bragg Reflection ◽  
Total Reflection ◽  
Resolving Power ◽  
X Rays ◽  
Spectrographic Analysis ◽  
Light Elements ◽  
X Ray ◽  
Alternative Approach ◽  
Very High

Spectrographic analysis of light elements by soft and ultrasoft fluorescent x-rays has become a useful technique for many applications of elemental analysis, using single crystals, soap multilayers and a combination of total reflection and filtering.Instead of the wavelength dispersive method based on Bragg reflection which provides high resolution combined with low reflecting intensity, monochromatization combining total reflection by a selected mirror and an appropriate filter offered an alternative approach in order to increase measurable intensity with reasonable spectral resolution.Recently, the use of synthetic multilayers, which are prepared by sputter/evaporation techniques, has been introduced for the detection of soft and ultrasoft x-rays. Studies on the use of these new wavelength dispersing devices have been conducted and it has been found that the reflectivity of these devices is very high compared with single crystals and soap multilayers and that their resolving power is fairly good.

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

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.

Determination of Boron Oxide in Glass by X-Ray Fluorescence Analysis

1982 ◽  
Vol 26 ◽  
pp. 423-430 ◽  
Author(s):  
T. Arai ◽  
T. Sohmura ◽  
H. Tamenori
Keyword(s):  
Cast Iron ◽  
Quantitative Determination ◽  
Bragg Reflection ◽  
Fluorescence Analysis ◽  
Total Reflection ◽  
X Ray ◽  
Alternative Approach ◽  
Steel Cast ◽  
Carbon Analysis

In the last few years, at the Denver X-Ray Analytical Conference, the author and co-workers presented two papers which described the principle and applications of carbon analysis by X-ray fluorescence based upon a monochromatization technique consisting of total reflection and filtering. Instead of the wavelength dispersive method based on Bragg reflection, this monochromatization, combining total reflection by a selected mirror and an appropriate filter, offered an alternative approach for the purpose of increasing measured X-ray intensity. The analytical performance of quantitative determination of carbon content in steel, cast iron and coal were reported.

The Application of Linear Polarized X-rays After Bragg Reflection for X-ray Fluorescence Analysis

1984 ◽  
Vol 28 ◽  
pp. 69-74 ◽  
Author(s):  
Peter Wobrauschek ◽  
Hannes Aiginger
Keyword(s):  
Single Crystals ◽  
Bragg Reflection ◽  
Fluorescence Analysis ◽  
Exciting Radiation ◽  
X Rays ◽  
Characteristic Radiation ◽  
Limits Of Detection ◽  
X Ray ◽  
Source Sample ◽  
Lower Limits

AbstractPolarized x-rays are used to excite samples of any kind and shape to emit characteristic radiation. In the appropriate geometry, where source-sample-ED detector are in any orthogonal position to each other, the exciting poLarized x-rays will be practically not scattered from sample and substrate into the detector. This reduces the background considerably and hence improves the lower limits of detection. The production of intensive polarized x-rays is done by using a single crystal-where Bragg reflection occurs at an angle 2 θ = 90° instead of amorphous low Z scatterers. The result is a linear polarized and monochromatic beam. The use of curved crystals instead of plane single crystals further increases the intensity of the exciting radiation. The lower limits of detection attainable with the recently constructed compact polarizer device are in the sub ppm range or in absolute amounts around 150 pg for medium Z elements.

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.

Determination of Oxygen and Nitrogen in Various Materials by X-Ray Fluorescence Spectrometry

1983 ◽  
Vol 27 ◽  
pp. 547-556 ◽  
Author(s):  
T. Arai ◽  
S. Ohara
Keyword(s):  
Bragg Reflection ◽  
Total Reflection ◽  
Fluorescence Spectrometry ◽  
X Rays ◽  
Spectrographic Analysis ◽  
X Ray ◽  
The Past ◽  
Detector Window ◽  
High Absorption

Spectrographic analysis for carbon and boron using fluorescent x-rays has been studied over the past few years; principles and applications for using those ultra-soft x-rays were described, based on the combination of total reflection and filtering rather than on the wavelength dispersive method of Bragg reflection (1, 2). However, oxygen and nitrogen, with x-ray wavelengths of 23.7lÅ and 31.60Å, respectively, cannot be detected as easily because of their high absorption by the detector window materials such as polypropylene, polyester or formvar films.

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