scholarly journals Single crystal diffraction at high energy and high pressure on I15 at DLS

2014 ◽  
Vol 70 (a1) ◽  
pp. C402-C402
Author(s):  
Nicola Casati ◽  
Annette Kleppe ◽  
Fabrizio Nestola ◽  
Heribert Wilhelm
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
High Energy ◽  
Quality Data ◽  
Extreme Condition ◽  
X Rays ◽  
Ambient Conditions ◽  
Single Crystal Diffraction ◽  
Natural Diamonds ◽  
Very High

The Extreme Condition beamline (I15) at the Diamond Light Source is a dedicated beamline for powder as well as single crystal diffraction on samples at extreme conditions in pressure or temperature. Single crystal data on either pressurized samples in a diamond anvil cell (DAC) or at ambient conditions are routinely done on a diffractometer scanning φ and ω using X-rays with energies in the range from 20 keV to 80 keV. Depending on the sample beam sizes varying from 20 μm to several 100 μm can be used. Data are recorded with an Atlas CCD (Agilent Technologies) and then treated with the Crysalis software package. In this contribution we highlight the very high accuracy of single-crystals data obtainable at I15 on two examples of single crystals in a DAC (E = 40 keV) and a sample at ambient conditions (E = 60 keV). A single crystal of the binary transition metal compound FeGe (B20 structure, space group P213, Z=4) was studied up to 11 GPa to determine the evolution of the inter-atomic distances (both atoms occupy the 4a Wyckoff positions). More than 200 unique data could be used to refine 7 parameters with an average R1 on all data of ~7%. Very high quality data have also been obtained for single crystals from the field of chemical crystallography, for which not only connectivity but also small bonding features can be detected. For example in l,6;8,13 biscarbonyl[14]annulene the progressive loss of aromatic character could be monitored and, in a special setup, the data allowed for the refinement of an unconstrained multipolar model. The use of 60 keV photons was crucial for an experiment on natural diamonds containing a variety of inclusions. At these energies the absorption of the diamond can be neglected. The aim of the study was to obtain information on possible recurrent crystallographic relationships between the inclusions and the diamond host on a significant number of extremely rare natural diamonds containing minerals.

High-energy resolution in X-ray scattering with the spectrometer INELAX. I. The principles and the test instrument

1991 ◽  
Vol 24 (6) ◽  
pp. 1042-1050 ◽  
Author(s):  
E. Burkel ◽  
B. Dorner ◽  
Th. Illini ◽  
J. Peisl
Keyword(s):  
Energy Resolution ◽  
High Energy ◽  
Bragg Angle ◽  
High Energy Resolution ◽  
X Rays ◽  
Test Results ◽  
X Ray Scattering ◽  
Radiation Sources ◽  
Very High Energy ◽  
Very High

Very high-energy resolution measurements using X-rays can be achieved by extreme backreflection (Bragg angle close to 90°) from perfect crystals. This technique, combined with the high intensity of X-rays emitted by synchrotron-radiation sources, allowed the development of the instrument INELAX for inelastic scattering experiments. The principles and test results are discussed.

Single crystal diffraction with X-rays and neutrons: High quality at high pressure?

1996 ◽  
Vol 14 (4-6) ◽  
pp. 341-352 ◽  
Author(s):  
W. F. Kuhs ◽  
F. C. Bauer ◽  
R. Hausmann ◽  
H. Ahsbahs ◽  
R. Dorwarth ◽  
...  
Keyword(s):  
High Pressure ◽  
Single Crystal ◽  
X Rays ◽  
High Quality ◽  
Single Crystal Diffraction

scholarly journals Monitoring of the radio galaxy M 87 at Very High Energy with MAGIC during a low emission state between 2012 and 2015

2016 ◽  
Vol 12 (S324) ◽  
pp. 164-167
Author(s):  
C. Arcaro ◽  
P. Bangale ◽  
M. Manganaro ◽  
D. Mazin ◽  
P. Colin ◽  
...  
Keyword(s):  
Radio Galaxy ◽  
Spectral Energy Distribution ◽  
Photon Emission ◽  
High Energy ◽  
Spectral Energy ◽  
X Rays ◽  
Low Emission ◽  
Very High Energy ◽  
Alternative Scenarios ◽  
Very High

AbstractWe present the preliminary results from observing the nearby radio galaxy M 87 for 156 hours (between the years 2012 and 2015) with the MAGIC telescopes, which lead to a significant very high energy (VHE, E > 100 GeV) detection of the source in quiescent states each year. Our VHE analysis combined with quasi-simultaneous data at other energies (from gamma-rays, X-rays, optical and radio) provides a unique opportunity to study the source variability and its broadband spectral energy distribution, which is found to disfavour a one-zone synchrotron/synchrotron self-Compton model. Therefore, other alternative scenarios for the photon emission are explored. We also find that the VHE emission is compatible with being produced close to the source radio core as previous data already indicated. A detailed paper presenting full results of the observing campaign is in preparation.

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.

scholarly journals A New Chapter in Hard X-rays of the M87 AGN

Proceedings ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 9
Author(s):  
Ka-Wah Wong ◽  
Rodrigo S. Nemmen ◽  
Jimmy A. Irwin ◽  
Dacheng Lin
Keyword(s):  
High Energy ◽  
X Rays ◽  
X Ray ◽  
Accretion Flow ◽  
Relativistic Jet ◽  
Very High Energy ◽  
Γ Ray ◽  
High Energy Emission ◽  
First Time ◽  
Very High

The nearby M87 hosts an exceptional relativistic jet. It has been regularly monitored in radio to TeV bands, but little has been done in hard X-rays ≳10 keV. For the first time, we have successfully detected hard X-rays up to 40 keV from its X-ray core with joint Chandra and NuSTAR observations, providing important insights to the X-ray origins: from the unresolved jet or the accretion flow. We found that the hard X-ray emission is significantly lower than that predicted by synchrotron self-Compton models introduced to explain very-high-energy γ -ray emission above a GeV. We discuss recent models to understand these high energy emission processes.

Very high energy y-rays from Cygnus X-3

1981 ◽  
Vol 301 (1462) ◽  
pp. 633-634 ◽  
Keyword(s):  
Light Curve ◽  
High Energy ◽  
Crimean Astrophysical Observatory ◽  
Sharp Peak ◽  
X Rays ◽  
Very High Energy ◽  
Time Variations ◽  
Comparison Of The Results ◽  
Very High

Very high energy y-rays (above 10 12 eV) from Cyg X-3 have been observed for 7 years at the Crimean Astrophysical Observatory by means of the Cherenkov technique. These observations enable us to find the derivative with time of the 4.8 hour periodicity. As is well known, the observations of X -rays have revealed time variations of the Cyg X-3 period (see, for instance, Eisner et al. 1979). The ‘light’ curve for very high energy y-rays has a sharp peak lasting 15 minutes and differs significantly from the ‘light’ curve for X-rays. For this reason the comparison of the results in these two regions is important.

scholarly journals Ruthenacarborane–Phenanthroline Derivatives as Potential Metallodrugs

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2322
Author(s):  
Martin Kellert ◽  
Imola Sárosi ◽  
Rajathees Rajaratnam ◽  
Eric Meggers ◽  
Peter Lönnecke ◽  
...  
Keyword(s):  
Single Crystal ◽  
Diffraction Analysis ◽  
Organic Solvents ◽  
Side Product ◽  
Ambient Conditions ◽  
Carbonyl Ligand ◽  
Single Crystal Diffraction ◽  
Solubility In Water ◽  
Low Solubility

Ruthenium-based complexes have received much interest as potential metallodrugs. In this work, four RuII complexes bearing a dicarbollide moiety, a carbonyl ligand, and a phenanthroline-based ligand were synthesized and characterized, including single crystal diffraction analysis of compounds 2, 4, and 5 and an observed side product SP1. Complexes 2–5 are air and moisture stable under ambient conditions. They show excellent solubility in organic solvents, but low solubility in water.

Indexing of multi-particle diffraction data in a high-pressure single-crystal diffraction experiment

2013 ◽  
Vol 46 (2) ◽  
pp. 387-390 ◽  
Author(s):  
Hui Li ◽  
Xiaodong Li ◽  
Meng He ◽  
Yanchun Li ◽  
Jing Liu ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
High Pressure ◽  
Single Crystal ◽  
Single Crystals ◽  
Diffraction Data ◽  
Reciprocal Lattice ◽  
Powder Pattern ◽  
Diffraction Experiment ◽  
Crystal Data ◽  
Single Crystal Diffraction

High-pressure single-crystal diffraction experiments often suffer from the crushing of single crystals due to the application of high pressure. Consequently, only diffraction data resulting from several particles in random orientations is available, which cannot be routinely indexed by commonly used methods designed for single-crystal data. A protocol is proposed to index such diffraction data. The techniques of powder pattern indexing are first used to propose the possible lattice parameters, and then a genetic algorithm is applied to determine the orientation of the reciprocal lattice for each of the particles. This protocol has been verified experimentally.

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