Radical increase of the parametric X-ray intensity under condition of extremely asymmetric diffraction

TL;DR

This paper predicts a significant increase in parametric X-ray radiation intensity when using extremely asymmetric diffraction geometry, potentially enhancing experimental detection by two orders of magnitude.

Contribution

It introduces the concept of using EAD geometry for PXR, demonstrating a theoretical increase in intensity based on dynamical diffraction theory.

Findings

PXR intensity can be increased two orders of magnitude in EAD geometry.

The entire crystal length contributes to X-ray emission in EAD, unlike in Laue and Bragg geometries.

Feasibility of experimental detection of PXR-EAD is discussed.

Abstract

Parametric X-ray radiation (PXR) from relativistic electrons moving in a crystal along the crystal-vacuum interface is considered. In this geometry the emission of photons is happening in the regime of extremely asymmetric diffraction (EAD). In the EAD case the whole crystal length contributes to the formation of X-ray radiation opposed to Laue and Bragg geometries, where the emission intensity is defined by the X-ray absorption length. We demonstrate that this phenomenon should be described within the dynamical theory of diffraction and predict a radical increase of the PXR intensity. In particular, under realistic electron-beam parameters, an increase of two orders of magnitude in PXR-EAD intensity can be obtained in comparison with conventional experimental geometries of PXR. In addition we discuss in details the experimental feasibility of the detection of PXR-EAD.