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1
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Study of Instrumental Factors Affecting X-Ray Isochromat Spectra

100%
Pełka J. B.
Acta Physica Polonica A
|
1994
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vol. 86
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issue 5
753-762
EN
In the present paper a model of an apparatus function for the bremsstrahlung isochromat spectroscopy method is proposed. The study presented in this work is based on experimental results obtained with a particular spectrometer working at the quantum energy of Cr K_{α1} (5414 eV). However, most of implications are general for the bremsstrahlung isochromat spectroscopy independently of particular construction of a spectrometer. From the theoretical considerations it was found that the total apparatus function, F_{t}, is composed of two main subfunctions in such a manner that F_{t} is not necessarily constant along the isochromat spectrum. The properties of the function as well as the question how it influences the measured spectra are discussed. Considerations presented in this paper are limited to the most essential instrumental factors broadening the bremsstrahlung isochromat spectra which can be described in terms of the apparatus function. In order to estimate the width of the apparatus function some experimental results of bremsstrahlung isochromat spectroscopy measurements of chosen substances with various apparatus settings are shown.
2
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Grazing Incidence X-Ray Reflectivity Study of MBE-Grown Co/Cu Multilayers

51%
Pełka J. B., Baczewski L. T., Wawro A., Domagała J.
Acta Physica Polonica A
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1997
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vol. 91
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issue 5
859-863
EN
In this work we report preliminary grazing-incidence X-ray reflectometry studies of multilayer structures composed of 3d metals Co and Cu deposited in the ultra-high vacuum molecular beam epitaxy system. The multilayers of different modulation period were deposited on glass substrate directly, or on 3d -metallic buffers of various thicknesses. The experimental specular reflectivity spectra were analyzed by a comparison with a theoretical model calculated from a recursive algorithm based on the Fresnel formula [1, 2]. It enabled us to estimate the structural parameters concerning layer thickness and roughness. The results obtained are correlated with magnetization measurements of the layered structures, as a function of modulation period, buffer type and thickness. A special attention to influence of interfacial roughness on magnetization results is paid.
3
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Study of Photoelectron Emission Yield from Layered Structures in Presence of Resonance-Enhanced X-Ray Propagation Effect

45%
Pełka J. B., Lagomarsino S., Cedola A., Di Fonzo S., Jark W.
Acta Physica Polonica A
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1997
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vol. 91
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issue 5
851-857
EN
In this work we present the new experimental results of total photoelectric yield as well as energy distribution of photoelectrons excited in a thin carbon film deposited on Ni mirror in the presence of resonance-enhanced X-ray propagation effect. The measurements were performed using conventional X-ray tube as a radiation source for the energy Cu K_{α} (8047 keV). The spectra were recorded using a flow proportional electron counter with energy resolution of about 15%, and multichannel pulse height analyzer. A comparison with the reflectivity spectra recorded at the same time show an excellent correlation of both kinds of spectra, consistently with the theoretical prediction. A map of electron energy distribution is reported. Although the applied electron counter was of low energetic resolution the recorded spectra show characteristic regularities and indicate that the photoelectron yield excited in the presence of resonance-enhanced X-ray propagation effect can provide depth dependent information about impurity distribution and processes in thin layers.
4
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Study of Si(111) Implanted with As Ions by X-Ray Diffraction and Grazing Incidence Methods

45%
Pełka J. B., Górecka J., Auleytner J., Domagała J., Bąk-Misiuk J.
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EN
The Si(111) wafer cut from a bulk single crystal obtained by the Czochralski method was implanted with 5×10^{16} I cm^{-2} of As ions of energy 80 keV. The dose applied was chosen above the amorphization limit of the silicon substrate. Two samples, implanted and a reference, were studied by grazing incidence X-ray reflectometry and X-ray diffraction methods using a high resolution Philips MRD system equipped with a Cu source and a channel-cut monochromator. The obtained spectra were compared with distributions of ion range and defect production calculated with TRIM program [1], as well as with theoretical models of reflectivity [2, 3]. The results of grazing incidence X-ray reflectometry reflectivity of the implanted sample show well-pronounced oscillations, which can be associated with a layer about 50 nm thick, approximately comparable to the thickness of the defected layer estimated from the TRIM method. Theoretical calculations of reflectivity clearly indicate an occurrence of a Si layer of electron density lower about 10-15% comparing to the unimplanted Si sample. This can be due to the vacancy production during ion implantation. A comparison of the spectra with a density distribution profile concluded from the TRIM calculations shows large discrepancies. The results indicate the applicability of grazing incidence X-ray reflectometry method in a study of amorphization processes in implanted layers.
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