اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدRadical increase of the parametric X-ray intensity under condition of extremely asymmetric diffraction
70
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
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.
قيم البحث
اقرأ أيضاً
Time evolution of the parametric X-Ray radiation, produced by a relativistic charged particle passing through a crystal, is studied. The most attention is given to the cases when the radiation lasts much longer (t_{PXR} ~0.1 ns) than the the time t_p
of the particle flight through the crystal (t_p ~ 1 ps). It is shown that such long duration of the radiation makes possible the detailed experimental investigation of the complicated time structure of the parametric X-ray pulses, generated by electron bunches, which are available with modern acceleration facilities.
An optics-free method is proposed to generate X-ray radiation with spatially variant states of polarization via an afterburner extension to a Free Electron Laser (FEL). Control of the polarization in the transverse plane is obtained through the overl
ap of different coherent transverse light distributions radiated from a bunched electron beam in two consecutive orthogonally polarised undulators. Different transverse profiles are obtained by emitting at a higher harmonic in one or both of the undulators. This method enables the generation of beams structured in their intensity, phase, and polarization - so-called Poincare beams - at high powers with tunable wavelengths. Simulations are used to demonstrate the generation of two different classes of light with spatially inhomogeneous polarization - cylindrical vector beams and full Poincare beams.
Low energy muon experiments such as mu2e and g-2 have a limited energy spread acceptance. Following techniques developed in muon cooling studies and the MICE experiment, the number of muons within the desired energy spread can be increased by the mat
ched use of wedge absorbers. More generally, the phase space of muon beams can be manipulated by absorbers in beam transport lines. Applications with simulation results are presented.
A structural understanding of whole cells in three dimensions at high spatial resolution remains a significant challenge and, in the case of X-rays, has been limited by radiation damage. By alleviating this limitation, cryogenic coherent diffraction
imaging (cryo-CDI) could bridge the important resolution gap between optical and electron microscopy in bio-imaging. Here, we report for the first time 3D cryo-CDI of a whole, frozen-hydrated cell - in this case a Neospora caninum tachyzoite - using 8 keV X-rays. Our 3D reconstruction reveals the surface and internal morphology of the cell, including its complex, polarized sub-cellular architecture with a 3D resolution of ~75-100 nm, which is presently limited by the coherent X-ray flux and detector size. Given the imminent improvement in the coherent X-ray flux at the facilities worldwide, our work forecasts the possibility of routine 3D imaging of frozen-hydrated cells with spatial resolutions in the tens of nanometres.
In this paper we present the method and experimental results of the investigation of a longitudinal component of relativistic electron electromagnetic field in the shadow area of a transversal component. We show experimentally, that in a region, comp
arable with the formation length area no shadowing effect of the longitudinal component of relativistic electron electromagnetic field appears. This is important for understanding of possibility of the shadowing effect in Smith-Purcell radiation and some other radiation types.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
