Measurements of parametric X-rays from relativistic electrons in silicon crystals

1987 ◽  
Vol 21 (1-4) ◽  
pp. 49-55 ◽  
Author(s):  
Yu.N. Adishchev ◽  
A.N. Didenko ◽  
V.V. Mun ◽  
G.A. Pleshkov ◽  
A.P. Potylitsin ◽  
...  
Keyword(s):  
Relativistic Electrons ◽  
X Rays ◽  
Silicon Crystals

scholarly journals Radio and X-ray connection in radio mini-halos: Implications for hadronic models

2020 ◽  
Vol 640 ◽  
pp. A37 ◽  
Author(s):  
A. Ignesti ◽  
G. Brunetti ◽  
M. Gitti ◽  
S. Giacintucci
Keyword(s):  
Magnetic Field ◽  
Large Fraction ◽  
Cosmic Ray ◽  
Physical Parameters ◽  
Model Parameters ◽  
Relativistic Electrons ◽  
X Rays ◽  
X Ray ◽  
Hadronic Model ◽  
Radio Halos

Context. A large fraction of cool-core clusters are known to host diffuse, steep-spectrum radio sources, called radio mini-halos, in their cores. Mini-halos reveal the presence of relativistic particles on scales of hundreds of kiloparsecs, beyond the scales directly influenced by the central active galactic nucleus (AGN), but the nature of the mechanism that produces such a population of radio-emitting, relativistic electrons is still debated. It is also unclear to what extent the AGN plays a role in the formation of mini-halos by providing the seeds of the relativistic population. Aims. In this work we explore the connection between thermal and non-thermal components of the intra-cluster medium in a sample of radio mini-halos and we study the implications within the framework of a hadronic model for the origin of the emitting electrons. Methods. For the first time, we studied the thermal and non-thermal connection by carrying out a point-to-point comparison of the radio and the X-ray surface brightness in a sample of radio mini-halos. We extended the method generally applied to giant radio halos by considering the effects of a grid randomly generated through a Monte Carlo chain. Then we used the radio and X-ray correlation to constrain the physical parameters of a hadronic model and we compared the model predictions with current observations. Results. Contrary to what is generally reported in the literature for giant radio halos, we find that the mini-halos in our sample have super-linear scaling between radio and X-rays, which suggests a peaked distribution of relativistic electrons and magnetic field. We explore the consequences of our findings on models of mini-halos. We use the four mini-halos in the sample that have a roundish brightness distribution to constrain model parameters in the case of a hadronic origin of the mini-halos. Specifically, we focus on a model where cosmic rays are injected by the central AGN and they generate secondaries in the intra-cluster medium, and we assume that the role of turbulent re-acceleration is negligible. This simple model allows us to constrain the AGN cosmic ray luminosity in the range ∼1044−46 erg s−1 and the central magnetic field in the range 10–40 μG. The resulting γ-ray fluxes calculated assuming these model parameters do not violate the upper limits on γ-ray diffuse emission set by the Fermi-LAT telescope. Further studies are now required to explore the consistency of these large magnetic fields with Faraday rotation studies and to study the interplay between the secondary electrons and the intra-cluster medium turbulence.

scholarly journals Very High Energy γ-Ray Generation Near The Light Cylinder of an Axisymmetric Rotator: Cos-B Like γ-Ray Sources

1992 ◽  
Vol 128 ◽  
pp. 207-208
Author(s):  
S. V. Bogovalov ◽  
YU. D. Kotov
Keyword(s):  
High Energy ◽  
Relativistic Electrons ◽  
X Rays ◽  
Inverse Compton Scattering ◽  
Light Cylinder ◽  
Radiation Spectra ◽  
Inverse Compton ◽  
Very High Energy ◽  
Γ Ray ◽  
Very High

AbstractSuper-hard γ-ray radiation spectra have been calculated. This radiation is generated near the velocity-of-light cylinder through the process of inverse-Compton scattering of relativistic electrons by thermal photons radiated by a neutron star. These calculations have been compared with observations of the Crab and Vela pulsars at 1000-GeV γ-ray energies. A correlation between γ-ray flares and those in soft (Ex ≃ lkeV) X-rays are predicted.

Effect of Compton Scattering on the Borrmann Effect of X-Rays in Silicon Crystals

1973 ◽  
Vol 28 (8) ◽  
pp. 1360-1365
Author(s):  
M. D. Giardina ◽  
A. Merlini
Keyword(s):  
Absorption Coefficient ◽  
Compton Scattering ◽  
Liquid Nitrogen ◽  
Dynamical Theory ◽  
Crystal Thickness ◽  
X Rays ◽  
Effective Absorption Coefficient ◽  
Silicon Crystals ◽  
Experimental Values ◽  
Integrated Intensities

The absolute integrated intensities diffracted in anomalous transmission through thick, nearly perfect crystals of silicon were measured for AgKα and MoKα wavelengths and for the {220} reflection, at room and liquid nitrogen temperatures. There is good agreement between experimental values and those calculated by using the formulas of the dynamical theory of diffraction, provided the contribution of Compton scattering μC* is included in the effective absorption coefficient μ*. μC* is a considerable fraction of μ* (from 23 to 55 per cent) for the two wavelengths and temperatures used in the present work. The experimental values of μC* agree well with those calculated by using the theory of the Compton contribution to the dynamical absorption coefficient of X-rays. A simple formula which is a good approximation of the rigorous expression of μC* is also given. The Debye temperature Θ of Si was derived from the experimental dependence of the intensities on crystal thickness for the {220} reflection at room and liquid nitrogen temperatures by using CuKα radiation. It was found that Θ = 521+5 and 543 + 5 °K at 295 and 77 °K, respectively, in agreement with the results of other authors.

Hard X rays of relativistic electrons accelerated in solar flares

2012 ◽  
Vol 52 (7) ◽  
pp. 875-882 ◽  
Author(s):  
I. V. Kudryavtsev ◽  
Yu. E. Charikov
Keyword(s):  
Solar Flares ◽  
Relativistic Electrons ◽  
X Rays

Effects of torsions on the integrated intensity of diffracted X-rays from silicon crystals

2005 ◽  
Vol 38 (6) ◽  
pp. 958-963 ◽  
Author(s):  
Takashi Saka
Keyword(s):  
Long Range ◽  
Present Model ◽  
Higher Order ◽  
Crystalline Material ◽  
Vertical Position ◽  
X Rays ◽  
Direction Parallel ◽  
Silicon Crystals ◽  
Integrated Intensity ◽  
Sensitive Method

A very sensitive method to detect long-range strain in otherwise perfect crystalline material has been proposed [Saka (2003).J. Appl. Cryst.36, 249–254]. In this method, the specimen was rotated around the scattering vector. By rotating the specimen, the integrated intensity of higher-order reflections was significantly increased from that in the initial vertical position. The results obtained were explained by assuming that the specimen was bent around an axis on the surface of the specimen, with the axis deviating slightly from the direction parallel to the edge of the specimen. In the present paper, it is shown that the results can be clearly explained by a model where the specimen is uniformly bent with a small torsion around the axes parallel to the specimen edges. The present model is highly probable, as the axes of the bending and torsion are parallel to the edges of the specimen.

The Munich Compact Light Source: initial performance measures

2016 ◽  
Vol 23 (5) ◽  
pp. 1137-1142 ◽  
Author(s):  
Elena Eggl ◽  
Martin Dierolf ◽  
Klaus Achterhold ◽  
Christoph Jud ◽  
Benedikt Günther ◽  
...  
Keyword(s):  
Light Source ◽  
Large Scale ◽  
Source Size ◽  
Relativistic Electrons ◽  
X Rays ◽  
Beam Hardening ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Inverse Compton ◽  
Compact Light Source

While large-scale synchrotron sources provide a highly brilliant monochromatic X-ray beam, these X-ray sources are expensive in terms of installation and maintenance, and require large amounts of space due to the size of storage rings for GeV electrons. On the other hand, laboratory X-ray tube sources can easily be implemented in laboratories or hospitals with comparatively little cost, but their performance features a lower brilliance and a polychromatic spectrum creates problems with beam hardening artifacts for imaging experiments. Over the last decade, compact synchrotron sources based on inverse Compton scattering have evolved as one of the most promising types of laboratory-scale X-ray sources: they provide a performance and brilliance that lie in between those of large-scale synchrotron sources and X-ray tube sources, with significantly reduced financial and spatial requirements. These sources produce X-rays through the collision of relativistic electrons with infrared laser photons. In this study, an analysis of the performance, such as X-ray flux, source size and spectra, of the first commercially sold compact light source, the Munich Compact Light Source, is presented.

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