Comparison of DTR spectral-angular characteristics of divergent beam of relativistic electrons in scattering geometry of Laue and Bragg

11th International Symposium on Radiation from Relativistic Electrons in Periodic Structures

Blazhevich, S.V.^1 ; Koskova, T.V.^1 ; Ligidov, A.Z.^1 ; Noskov, A.V.^1

Belgorod State University, Belgorod, Russia^1

关键词: Angular characteristics;    Asymmetric reflections;    Diffracted transition radiation;    Divergence measurement;    Numerical calculation;    Parametric X-ray radiation;    Scattering geometries;    Single-crystal plates;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/732/1/012014/pdf
DOI  :  10.1088/1742-6596/732/1/012014

来源: IOP

【 摘 要 】

Diffracted transition radiation (DTR) generated by a divergent beam of relativistic electrons crossing a single-crystal plate in different (Laue, Bragg) scattering geometry has been considered for the general case of asymmetric reflection of the electron coulomb field relative to the entrance target surface. The expressions for spectral-angular density of DTR and parametric X-ray Radiation (PXR) has been derived. Then DTR and PXR has been considered in case of a thin target, when multiple scattering of electron is negligibly small, which is important for divergence measurement in real time regime. Numerical calculation of spectral-angular density of DTR by a beam of relativistic electrons has been made using averaging over the bivariate Gauss distribution as angular distribution of relativistic electrons in the beam. It has been shown that in Bragg scattering geometry the angular density of DTR is bigger, than in Laue geometry, which can be explained by the existence of the frequency range, in which the incident wave propagation vector takes complex value even under absence of absorption. In this range, all of photons are reflected in Bragg direction. It means that the range of total reflection defines the width of DTR spectrum.