scholarly journals The XMM-Newton serendipitous survey

2020 ◽  
Vol 641 ◽  
pp. A136 ◽  
Author(s):  
N. A. Webb ◽  
M. Coriat ◽  
I. Traulsen ◽  
J. Ballet ◽  
C. Motch ◽  
...  
Keyword(s):  
Ultra Violet ◽  
Source Detection ◽  
High Quality ◽  
Sky Surveys ◽  
X Ray ◽  
Science Centre ◽  
Data Products

Context. Sky surveys produce enormous quantities of data on extensive regions of the sky. The easiest way to access this information is through catalogues of standardised data products. XMM-Newton has been surveying the sky in the X-ray, ultra-violet, and optical bands for 20 years. Aims. The XMM-Newton Survey Science Centre has been producing standardised data products and catalogues to facilitate access to the serendipitous X-ray sky. Methods. Using improved calibration and enhanced software, we re-reduced all of the 14 041 XMM-Newton X-ray observations, of which 11 204 observations contained data with at least one detection and with these we created a new, high quality version of the XMM-Newton serendipitous source catalogue, 4XMM-DR9. Results. 4XMM-DR9 contains 810 795 detections down to a detection significance of 3σ, of which 550 124 are unique sources, which cover 1152 degrees2 (2.85%) of the sky. Filtering 4XMM-DR9 to retain only the cleanest sources with at least a 5σ detection significance leaves 433 612 detections. Of these detections, 99.6% have no pileup. Furthermore, 336 columns of information on each detection are provided, along with images. The quality of the source detection is shown to have improved significantly with respect to previous versions of the catalogues. Spectra and lightcurves are also made available for more than 288 000 of the brightest sources (36% of all detections).

scholarly journals Short-pulse laser-driven x-ray radiography

2016 ◽  
Vol 4 ◽  
Author(s):  
E. Brambrink ◽  
S. Baton ◽  
M. Koenig ◽  
R. Yurchak ◽  
N. Bidaut ◽  
...  
Keyword(s):  
Pulse Laser ◽  
Short Pulse ◽  
Incident Angle ◽  
Laboratory Astrophysics ◽  
Signal To Noise ◽  
High Quality ◽  
X Ray ◽  
Short Pulse Laser ◽  
Short Pulse Lasers

We have developed a new radiography setup with a short-pulse laser-driven x-ray source. Using a radiography axis perpendicular to both long- and short-pulse lasers allowed optimizing the incident angle of the short-pulse laser on the x-ray source target. The setup has been tested with various x-ray source target materials and different laser wavelengths. Signal to noise ratios are presented as well as achieved spatial resolutions. The high quality of our technique is illustrated on a plasma flow radiograph obtained during a laboratory astrophysics experiment on POLARs.

High Quality Hydrothermal ZnO Crystals

1998 ◽  
Vol 537 ◽  
Author(s):  
M. Suscavage ◽  
M. Harris ◽  
D. Bliss ◽  
P. Yip ◽  
S.-Q. Wang ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Liquid Helium ◽  
Room Temperature ◽  
Surface Preparation ◽  
Critical Factor ◽  
High Quality ◽  
Rocking Curve ◽  
X Ray ◽  
Oxide Crystals

AbstractZinc Oxide crystals have historically been grown in hydrothermal autoclaves with a basic mineralizer; however, doubts have been raised about the quality of such crystals because they have often exhibited large x-ray rocking curve widths and low photoluminescence (PL) yield with large linewidths. Several ZnO crystals were grown hydrothermally and sliced parallel to the c-plane. This resulted in opposite surfaces (the C+ and C-) exhibiting pronounced chemical and mechanical differences. Different surface treatments were investigated and compared by PL both at room temperature and liquid helium temperatures, and by double axis X-ray rocking curve measurements. The high quality of hydrothermally-grown ZnO is substantiated by the narrow rocking curve widths and sharp PL peaks obtained. A critical factor in obtaining these results was found to be surface preparation.

Characterization and Growth Mechanism of B12As2 Epitaxial Layers Grown on (1-100) 15R-SiC

2008 ◽  
Vol 1069 ◽  
Author(s):  
Hui Chen ◽  
Guan Wang ◽  
Michael Dudley ◽  
Zhou Xu ◽  
James. H. Edgar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Growth Mechanism ◽  
Heteroepitaxial Growth ◽  
High Quality ◽  
X Ray ◽  
Transmission Electron ◽  
Substrate Choice

ABSTRACTA systematic study is presented of the heteroepitaxial growth of B12As2 on m-plane 15R-SiC. In contrast to previous studies of B12As2 on other substrates, including (100) Si, (110) Si, (111) Si and (0001) 6H-SiC, single crystalline and untwinned B12As2 was achieved on m-plane 15R-SiC. Observations of IBA on m-plane (1100)15R-SiC by synchrotron white beam x-ray topography (SWBXT) and high resolution transmission electron microscopy (HRTEM) confirm the good quality of the films on the 15R-SiC substrates. The growth mechanism of IBA on m-plane 15R-SiC is discussed. This work demonstrates that m-plane 15R-SiC is potentially a good substrate choice to grow high quality B12As2 epilayers.

Processing of the lead-zinc ore from the Pavlovsk deposit

2020 ◽  
pp. 33-39
Author(s):  
S. S. Plyasovitsa ◽  
◽  
O. A. Kravtsova ◽  
N. V. Ivanova ◽  
I. Yu. Semenov ◽  
...  
Keyword(s):  
Metal Concentration ◽  
High Quality ◽  
Valuable Component ◽  
Flotation Process ◽  
X Ray ◽  
Lead And Zinc ◽  
Mineralogical Study ◽  
Lead Zinc ◽  
Zinc Concentrate

The authors carried out a mineralogical study and substantiated a concentration process developed for the lead-zinc ores of the Pavlovsk deposit. The concentration of the valuable component in each type of concentrate is determined by the amount of pyrite contained in the ore. It was established that the main loss of lead with flotation tailings is associated with oxidized phases, which are mainly found in fine material. Lead sulphides account for 30% of the entire waste tailings. Using the results of the mineralogical study, a flotation process was developed that involves a staged separation of commercial lead and zinc concentrates, as well as waste tailings. The obtained zinc concentrate has a consistently high quality of 57–58% with an 85–90% recovery. The metal concentration in the lead concentrate 1 is 45%, with the recovery being 43%. On the basis of the experimental results, the authors propose to use an X-ray radiometric separation method for coarse ore, which will help reduce the amount of incoming ore by 30% while minimizing the loss of lead and zinc.

scholarly journals Predicting Tomato Seedling Morphology by X-ray Analysis of Seeds

1994 ◽  
Vol 119 (2) ◽  
pp. 258-263 ◽  
Author(s):  
W.J. van der Burg ◽  
J.W. Aartse ◽  
R.A van Zwol ◽  
H. Jalink ◽  
R.J. Bino
Keyword(s):  
Free Space ◽  
Evaluation Procedure ◽  
Germination Test ◽  
High Quality ◽  
Seedling Morphology ◽  
Tomato Seedling ◽  
X Ray ◽  
Size And Morphology ◽  
Selection Of

Studies based on X-ray photographs were conducted to predict the morphology of tomato (Lycopersicon esculentum Mill.) seedlings at transplanting stage. Currently, seed-lot quality of tomato seeds for growing commercial transplants is determined with grow-out tests in the greenhouse because the standard germination test fails to predict the percentage of normal or usable transplants (UTs). These grow-out tests, however, are difficult to standardize. An X-ray evaluation procedure is presented as an alternative. X-ray images nondestructively provide information on embryo size and morphology and the amount of endosperm and the area of free space. These parameters correlate well with the morphology of 14-day old seedlings. Cotyledon morphology has the highest correlation with the percentage of UTs. A test based on the evaluation of X-ray images, classifying the cotyledon morphology and seed free space, predicts the percentage of UTs more accurately than the currently used germination test. A second method based on an equation that uses the probabilities of all X-ray categories proportionally predicts the percentage of UTs of primed seeds more accurately than the first method. Selecting individual seeds based on X-ray images has the potential to raise the percentage of UTs of seed lots. On the average, the percentage of UTs of control seeds was 22% higher after hand selection based on X-ray evaluation. Primed seeds gave 12% higher results. Hence, X-ray analysis can predict seedling performance and enable the selection of high-quality seeds.

Deep Chandra observations of the core of the Perseus cluster

2018 ◽  
Vol 14 (S342) ◽  
pp. 127-132
Author(s):  
Jeremy S. Sanders
Keyword(s):  
Spatial Scales ◽  
High Quality ◽  
X Ray ◽  
The Core ◽  
Spatially Resolved ◽  
Spatially Resolved Spectroscopy ◽  
Perseus Cluster ◽  
Metallicity Distribution

AbstractThe Perseus cluster is the X-ray brightest cluster in the sky and with deep Chandra observations we are able to map its central structure on very short spatial scales. In addition, the high quality of X-ray data allows detailed spatially-resolved spectroscopy. In this paper I review what these deep observations have told us about AGN feedback in clusters, sloshing and instabilities, and the metallicity distribution.

scholarly journals Comparison of the Quality of Protein Crystals Grown by CLPC Seeds Method

Crystals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 501 ◽  
Author(s):  
Li ◽  
Yan ◽  
Liu ◽  
Wu ◽  
Liu ◽  
...  
Keyword(s):  
Diffraction Data ◽  
Protein Crystal ◽  
Protein Crystals ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
High Quality Protein

We present a systematic quality comparison of protein crystals obtained with and without cross-linked protein crystal (CLPC) seeds. Four proteins were used to conduct the experiments, and the results showed that crystals obtained in the presence of CLPC seeds exhibited a better morphology. In addition, the X-ray diffraction data showed that the CLPC seeds method is a powerful tool to obtain high-quality protein crystals. Therefore, we recommend the use of CLPC seeds in preparing high-quality diffracting protein crystals.

scholarly journals Low Multiplicity Sulfur SAD Phasing in the Home lab

2014 ◽  
Vol 70 (a1) ◽  
pp. C607-C607 ◽  
Author(s):  
Severine Freisz ◽  
Juergen Graf ◽  
Matthew Benning ◽  
Vernon Smith
Keyword(s):  
De Novo ◽  
Structural Information ◽  
Low Noise ◽  
Intensity Difference ◽  
Anomalous Scattering ◽  
High Quality ◽  
X Ray ◽  
Sad Phasing ◽  
Very High

Advances in crystallographic hardware and software are enabling structural biologists to investigate more challenging projects. Recent developments in hardware and software are greatly increasing the capabilities of in-house diffraction systems making it more routine to obtain de novo structural information in the home lab. Single-wavelength anomalous diffraction (SAD) techniques with Cu Ka or Ga Ka radiation are now widely used for structure solution even in cases involving weak anomalous scatterers, like sulfur. We have now introduced the D8 Venture solution for structural biology with the PHOTON 100 detector featuring the first CMOS active pixel sensor for X-ray crystallography. Our new microfocus source, the METALJET delivers beam intensity exceeding those of typical bending-magnet beamlines. The very high intensity, the small beam focus and the lower air scatter produced by Gallium Kα radiation help to greatly reduce the background scatter. This provides greater signal to noise essential to identify weak anomalous signal. Due to the very weak anomalous scattering of S, data multiplicities in the order of 40 are typically necessary to obtain phases by S-SAD. Collecting high-multiplicity data minimizes systematic experimental errors to measure with very high accuracy the minute intensity difference between Friedel Pairs (1.0 – 1.5 %) [1]. This requires software which optimizes the collection strategy, for example with respect to overall data collection time to minimize radiation damage. The combination of a brighter, more stable X-ray source with a high sensitivity low noise detector have greatly improved the quality of data collected in-house. The high quality allows successful SAD measurements far away from the absorption edge. Here we present a low multiplicity sulfur-SAD phasing experiment on a small Thaumatin crystal showing the high quality of the data collected on the D8 VENTURE with the METALJET.

Effect of doping on crystalline quality of rubidium titanyl phosphate (RTP) crystals grown by the TSSG method

2014 ◽  
Vol 1698 ◽  
Author(s):  
Jianqiu Guo ◽  
Balaji Raghothamachar ◽  
Michael Dudley ◽  
Joan J. Carvajal ◽  
Ali Butt ◽  
...  
Keyword(s):  
Growth Process ◽  
Solution Growth ◽  
Crystalline Quality ◽  
Defect Structures ◽  
Growth Sector ◽  
High Quality ◽  
X Ray ◽  
Linear Defects ◽  
Top Seeded Solution Growth

ABSTRACTDefect structures in Rubidium Titanyl Phosphate (RTP) crystals (non-doped and doped) grown by the Top Seeded Solution Growth (TSSG) method were characterized using Synchrotron White Beam X-ray Topography. Main defects observed in non-doped crystals are growth sector boundaries while both growth sector boundaries and growth striations are observed in the Nb single doped and (Nb,Yb)-codoped crystals with relatively few linear defects such as dislocations. Results show that the overall crystalline quality is lowered as more doping elements are incorporated. Details of defect distributions are correlated with the growth process to facilitate high quality growth of doped RTP.

scholarly journals Floating Zone Growth of Sr Substituted Han Purple: Ba0.9Sr0.1CuSi2O6

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 273
Author(s):  
Pascal Puphal ◽  
Stephan Allenspach ◽  
Christian Rüegg ◽  
Ekaterina Pomjakushina
Keyword(s):  
Magnetic Susceptibility ◽  
Single Crystals ◽  
Inelastic Neutron ◽  
Floating Zone ◽  
X Ray Diffraction ◽  
High Quality ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Zone Growth

We present a route to grow single crystals of Ba 0.9 Sr 0.1 CuSi 2 O 6 suitable for inelastic neutron studies via the floating zone technique. Neutron single crystal diffraction was utilized to check their bulk quality and orientation. Finally, the high quality of the grown crystals was proven by X-ray diffraction and magnetic susceptibility.

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