Parametric x-ray radiation in polycrystals

Parametric X-ray radiation produced during the interaction of charged particles with polycrystals is regarded. A review of the existing theories, perspectives of application and performed experiments is presented. The evolution of experimental capabilities as well as the progress in the process comprehension is illustrated. The state of the art of PXR in polycrystals is presente

Parametric x-ray radiation in the backward geometry

Parametric X-ray Radiation registered in the backward geometry is analysed. The main properties of the radiation for such geometry are discussed. The advantages of the backward geometry over other configurations regarding the intensity, the spectral width and the possibility to discriminate the contributions form different radiation mechanisms to the total radiation yield are presente

Parametric X-ray radiation in polycrystals

Parametric X-ray radiation produced during the interaction of charged particles with polycrystals is regarded. A review of the existing theories, perspectives of application and performed experiments is presented. The evolution of experimental capabilities as well as the progress in the process comprehension is illustrated. The state of the art of PXR in polycrystals is presented.Розглянуто параметричне рентгенівське випромінювання (ПРВ), що виникає при взаємодії заряджених частинок з полікристалічними мішенями. Представлено огляд сучасного стану дослідження ПРВ в полікристалах: існуючих теорій, перспектив застосування і проведених експериментів з урахуванням розвитку експериментальних можливостей.Рассмотрено параметрическое рентгеновское излучение (ПРИ), возникающее при взаимодействии заряженных частиц с поликристаллическими мишенями. Представлен обзор современного состояния исследования ПРИ в поликристаллах: существующих теорий, перспектив применения и проведенных экспериментов с учетом развития экспериментальных возможностей

Parametric X-ray Radiation in the backward geometry

Parametric X-ray Radiation registered in the backward geometry is analysed. The main properties of the radiation for such geometry are discussed. The advantages of the backward geometry over other configurations regarding the intensity, the spectral width and the possibility to discriminate the contributions form different radiation mechanisms to the total radiation yield are presented.Аналізується параметричне рентгенівське випромінювання, зареєстроване в геометрії «строго назад». Обговорюються основні властивості випромінювання для такої геометрії. Представлено переваги геометрії «строго назад» у порівнянні з іншими геометріями в залежності від інтенсивності, спектральної ширини і можливості поділу внесків від різних механізмів випромінювання в загальний вихід випромінювання.Анализируется параметрическое рентгеновское излучение, зарегистрированное в геометрии «строго назад». Обсуждаются основные свойства излучения для такой геометрии. Представлены преимущества геометрии «строго назад» по сравнению с другими геометриями в зависимости от интенсивности, спектральной ширины и возможности разделения вкладов от различных механизмов излучения в общий выход излучения

Quasi freestanding graphene on SiC 0001 via cobalt intercalation of zero layer graphene

Modification of the electronic and crystal structure of zero layer graphene grown on 6H SiC 0001 after Co intercalation is reported. Using a wide range of techniques including angle resolved photoelectron spectroscopy, x ray photoelectron spectroscopy, Raman spectroscopy, low energy electron diffraction, we found that zero layer graphene on SiC transforms into graphene monolayer as a result of cobalt intercalation. The Dirac cone of amp; 960; band characteristic of quasi freestanding graphene is observed. In combination with high resolution transmission electron microscopy and atomic force microscopy data, we conclude that ultrathin silicide CoSi CoSi2 structure is formed between graphene and SiC substrate. Investigation of magnetic properties reveals ferromagnetic behavior with open hysteresis loop. The results of this work are the basis for further implementation of magneto spin orbit graphene on a semiconducting substrate and are important for the future application of such graphene in spintronic

A blueprint for the synthesis and characterization of thiolated graphene

Graphene derivatization to either engineer its physical and chemical properties or overcome the problem of the facile synthesis of nanographenes is a subject of significant attention in the nanomaterials research community. In this paper, we propose a facile and scalable method for the synthesis of thiolated graphene via a two step liquid phase treatment of graphene oxide GO . Employing the core level methods, the introduction of up to 5.1 at. of thiols is indicated with the simultaneous rise of the C O ratio to 16.8. The crumpling of the graphene layer upon thiolation without its perforation is pointed out by microscopic and Raman studies. The conductance of thiolated graphene is revealed to be driven by the Mott hopping mechanism with the sheet resistance values of 2.15 k amp; 937; sq and dependable on the environment. The preliminary results on the chemiresistive effect of these films upon exposure to ethanol vapors in the mix with dry and humid air are shown. Finally, the work function value and valence band structure of thiolated graphene are analyzed. Taken together, the developed method and findings of the morphology and physics of the thiolated graphene guide the further application of this derivative in energy storage, sensing devices, and smart material

Radiation Defects in Heterostructures 3C-SiC/4H-SiC

The effect of 8 MeV proton irradiation on n-3C-SiC epitaxial layers grown by sublimation on semi-insulating 4H-SiC substrates has been studied. Changes in sample parameters were recorded using the Hall-effect method and judged from photoluminescence spectra. It was found that the carrier removal rate (Vd) in 3C-SiC is ~100 cm−1, which is close to Vd in 4H-SiC. Compared with 4H and 6H silicon carbide, no significant increase in the intensity of the so-called defect-related photoluminescence was observed. An assumption is made that radiation-induced compensation processes in 3C-SiC are affected by structural defects (twin boundaries), which are always present in epitaxial cubic silicon carbide layers grown on substrates of the hexagonal polytypes