Theory of diffracted channeling radiation

Abstract

Monochromatic x-ray emission is predicted for MeV channeled electrons/positrons. The mechanism of this radiation is intuitively understood as diffraction of virtual channeling radiation into the direction of the Bragg angles with respect to the electron beam. Our numerical calculations predict that spectral density of the emitted x rays is about ten times larger than that of parametric x-ray radiation.

Coherent polarization radiation from crystals irradiated with relativistic charged particles

“…After the work, kinematical calculations appeared, showing that angular distributions of CPR from channeled electrons will be stronger and narrower Matsuda et al, 1996). Yabuki et al (2001) called this predicted effect ''diffracted channeling radiation'' and performed detailed numerical calculations taking into account the quantum channeling states as well as dynamical effect. It should be noted that this kind of ''hybrid'' radiation is not only possible for channeling radiation and CPR but also CBS and CPR.…”

Quantum effects for parametric X-ray radiation during channeling: Theory and first experimental observation

“…Following [1,4], we introduce the angular coordinates θ x and θ y , which describe the PXRC photon wave vec tor deviation from the Bragg direction:…”

“…The matrix element for PXRC was obtained in [4]. This matrix element was modified to take into account the band structure of transverse energy levels of chan neled electrons and avoid the dipole approximation, and has the form:…”

“…If the angle of incidence with respect to the chan neling planes (axes) is greater than the Lindhard criti cal angle θ L for channeling, the sub barrier quantum states are not populated and the formulas for PXRC transform into the well known formulas for PXR [4].…”

“…The kinematical theory of DCR was proposed in [2] and [3]. Later, the dynamical theory of DCR within the dipole approximation was developed for the case of planar channeling in [4]. In our previous reports [5][6][7], the theory of DCR in the dipole approximation was modified to take into account the band structure of transverse energy levels of channeled electrons and positrons.…”