Resonant transition radiation in the X-ray region from a low emittance 855 MeV electron beam

Parametric and resonant transition radiation in periodic stratified structures

We consider the problem of electromagnetic emission when an electrically charged particle crosses a periodically stratified structure following an arbitrary linear trajectory. A theory generalizing a recently developed method [Phys. Rev. E 63, 016613 (2001)] is presented in the framework of the classical theory of electromagnetism in continuous media. It allows one to account for both the so-called parametric radiation and the resonant transition radiation. We implement our model to interpret the experiments performed by Kaplin et al. [Appl. Phys. Lett. 76, 3647 (2000)] in the x-ray domain with a stack of 300 W/B(4)C bilayers irradiated by 500 MeV electrons.

Classical theory of resonant transition radiation in multilayer structures

A rigorous classical electromagnetic theory of the transition radiation in finite and infinite multilayer structures is presented. It makes the standard results of thin-film optics, such as the matrix formalism, accountable; it allows thus an exact treatment of the propagation of the waves induced by the electron. This method is applied to the particular case of the periodic structures to treat the resonant transition radiation (RTR). It is noted that the present theory gives, in the hard x-ray domain, results previously published. The reason for this approach is to make the numerical calculations rigorous and easy. The numerical results of our theory are compared to experimental RTR data obtained recently by Yamada et al. [Phys. Rev. A 59, 3673 (1999)] with a nickel-carbon multilayer structure.

Parametric X rays observed under bragg condition: boost of intensity by a factor of Two

Parametric x rays (PXR) produced by bombarding silicon and diamond crystals with electrons of 30 to 87 MeV were detected at 180 degrees relative to the direction of the electron beam. It was found that the dependence of the intensity on the orientation of the crystal agrees with the predictions of the kinematical theory of PXR. The absolute intensity is twice as large as predicted. These findings can be explained considering dynamical effects that govern the x-ray crystal interaction. Additionally, x rays caused by self-diffracted transition radiation have been observed.

Xuv resonant transition radiations from periodic stratified media

General formulation of the xuv intensity emitted when relativistic electrons cross through any periodic stratified medium is presented in the framework of electromagnetism in continuous media. Application is made to the resonant transition radiation emitted in the geometries of both normal and oblique incidence. In the first case, agreement is found between our calculated results and published values. Intensity emitted by a periodic multilayer stack used in the Bragg conditions is determined and the practical interest of a such a radiation source is discussed.