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1

Photoemission by Polarized X-Rays

100%

Tilinin I. S.

Acta Physica Polonica A

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1997

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vol. 91

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issue 5

887-892

EN

The angular distribution of photoelectrons excited by X-rays is strongly correlated with the degree and type of polarization of incident photons. The angular and energy spectrum of signal photoelectrons leaving a solid is considerably modified as compared to the differential photoelectric cross-section owing to elastic and inelastic collisions the electrons suffer on their way out of a target. In this report an analytical expression for the angular distribution of photoelectrons escaping from the sample without being scattered inelastically was found in the transport approximation. The dependence of the angular distribution on the parameters characterizing optical orientation and polarization of incident X-rays was studied in detail.

2

Signal Photoelectron Yield Dependence on the X-Ray Angle of Incidence

51%

Tilinin I. S., Jabłoński A., Lesiak-Orłowska B.

Acta Physica Polonica A

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1994

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vol. 86

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issue 5

853-859

EN

The photoelectron emission from solids irradiated by X-rays was described by the analytical theory of electron transport and simulated by the Monte Carlo technique. The medium energy electron transport problem is treated by means of a Boltzmann type kinetic equation satisfying appropriate boundary conditions. The solution of the transport equation was obtained in the transport approximation based on the generalized radiative field similarity principle. Simple and reliable formalism was derived for both the differential and the total photoelectron yields. The dependence of the photoelectron yield on the X-ray incidence angle and the "flattening" effect of multiple elastic scattering on the angular distribution of electrons leaving the target are analysed in detail. The photoelectron yields and angular distributions calculated by the Monte Carlo algorithm, based on a realistic differential elastic scattering cross-section, are in good agreement with the results found from analytical theory. It is shown that main characteristics of the photoelectron emission are determined primarily by two parameters: the inelastic and the transport mean free paths.

3

Mean Escape Depth of Signal Photoelectrons from Amorphous and Polycrystalline Solids

51%

Tilinin I. S., Jabłoński A., Lesiak-Orłowska B.

Acta Physica Polonica A

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1994

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vol. 86

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issue 5

845-852

EN

Escape depth of photoelectrons leaving a target without being scattered inelastically was submitted to extensive theoretical analysis. Dependence of the mean escape depth on the X-ray angle of incidence and the electron initial angular distribution inside the sample was considered. The Monte Carlo algorithm was developed basing on a differential elastic scattering cross-section calculated within the partial-wave expansion method and a realistic electron-atom interaction potential. The mean escape depth was evaluated by means of the depth distribution function found analytically by solving a kinetic equation and by the Monte Carlo technique. The agreement between the results obtained from two methods is excellent. Elastic scattering was found to reduce considerably the escape depth. This reduction may reach up to 25% in the case of heavy elements in the practical X-ray photoelectron spectroscopy analysis. It was shown that the mean escape depth expressed in units of the electron transport mean free path is a universal function of the ratio of the inelastic to the transport mean free paths, the asymmetry parameter and the X-ray angle of incidence. A simple explicit expression for this function is proposed.

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3 Acta Physica Polonica A

1 1997

2 1994

3 Tilinin I. S.

2 Jabłoński A.

2 Lesiak-Orłowska B.

Photoemission by Polarized X-Rays

Signal Photoelectron Yield Dependence on the X-Ray Angle of Incidence

Mean Escape Depth of Signal Photoelectrons from Amorphous and Polycrystalline Solids