Using mosaic crystals for the generation of intense X-ray beams

The parametric X-ray (PXR) yield due to 500-MeV electrons in a 2-mm-thick diamond crystal with a mosaicity angle of ~0.2 mrad has been studied. It is shown that the mosaic crystal structure leads to a significant (about fourfold) increase in the PXR yield doe to the contribution of diffracted bremsstrahlung radiationye

Estimation of microblock sizes in mosaic crystals according to fast electron radiation characteristics

The possibilities of a previously proposed technique for determining the characteristic sizes of microblocks in mosaic aα-class crystals have been analyzed. Determination is performed according to the ratio between the measured and calculated values for the diffraction suppression of the fixed-energy bremsstrahlung yield. The limits of applicability of the technique have been revealedyesBelgorod State Universit

Estimation of Crystal Sample Structure by Means of Fast Electron Radiation

An analysis is made of the dependence of the characteristics of X-ray radiation arising during the passage of fast electrons through the crystal on the quality of the internal structure of the sampleyesBS

Diffracted diffraction radiation and its application to beam diagnostics

We present theoretical considerations for diffracted diffraction radiation and also propose an application of this process to diagnosing ultra-relativistic electron (positron) beams for the first tim

New method of electron beam transverse size measurement by angular distribution of emission in a thin crystal

A technique is proposed for determining beam dimensions on a target by measuring two-dimensional angular distributions of the radiation for two distances between the crystal where the radiation is generated and a coordinate detector. The dimensions are determined from the results of a least squares method procedure with varying parameters, where the adjustable function is the distribution for a shorter distance and the fitting function is the convolution of the angular distribution at a greater distance with a twodimensional Gaussian distribution whose parameters are uniquely related to the beam dimensions on the target and the distances between the crystal and the detecto

Nitrided Ferroalloy Production By Metallurgical SHS Process: Scientific Foundations and Technology

The main objective of this paper is to present results of the research in the development of a specialized self-propagating high-temperature synthesis (SHS) technology for ferroalloy composites, as applied to steelmaking. The problem of creating such a production cycle has been solved by developing a new approach to the practical implementation of self-propagating high-temperature synthesis, as applied to metallurgy. The metallurgical variation of SHS is based on the use of different metallurgic alloys (including waste in the form of dust from ferroalloy production) as basic raw materials in the new process. Here, the process of synthesis by combustion is realized through exothermic exchange reactions. The process produces a composite, based on inorganic compositions with a bond of iron and/or alloy based on iron. It has been shown that in terms of the aggregate state of initial reagents, metallurgical SHS processes are either gasless or gas-absorbing. Combustion regimes significantly differ when realized in practice. To organize the metallurgical SHS process in weakly exothermic systems, different variations of the thermal trimming principle are used. In the present study, self-propagating high-temperature synthesis of ferrovanadium nitride, ferrochromium nitride and ferrosilicon nitride; which is widely used in steel alloying, was investigated. Keywords: self-propagating high-temperature synthesis (SHS); composite ferroalloys; nitrides; borides; filtration combustion; ferrovanadium nitride ferrochromium nitride and ferrosilicon nitrid

Diagrammatic approach to coherent backscattering of laser light by cold atoms: Double scattering revisited

We present a diagrammatic derivation of the coherent backscattering spectrum from two two-level atoms using the pump-probe approach, wherein the multiple scattering signal is deduced from single-atom responses, and provide a physical interpretation of the single-atom building blocks.Comment: 16 pages, 7 figure

Influence of crystals mosaicity on observed characteristics of X-ray emission along the propagation velocity of fast electrons in thick tungsten crystals

The results of a set of experiments on X-ray emission yield of ω ∼ γωp energy, generated by 500MeV energy electrons in oriented tungsten single crystals are presented. The experiments were performed at Tomsk synchrotron using Crystal grating spectrometers based on mosaic crystals of pyrolytic graphite. It is shown that the measurement results are caused by the competition of two mechanisms: parametric X-ray emission along the particle velocity and bremsstrahlung diffraction in mosaic crystals of aα group. A method for determining the characteristic bulk dimensions in mosaic crystals of aα group is suggested

Calculation of class-b mosaic crystals reflactivity by Monte Carlo techniqye

The technique is proposed and implemented to calculate the reflectivity of such crystals by Monte Carlo modeling, corrently considering the multiple reflections of photons inside the crystal and the geometry of experiment for random distribution of the mosaicyesBelgorod State Universit