Goniometer Stop for Use with Large Sample Chamber in G.E. X-RD5 X-Ray Spectrograph

1971 ◽  
pp. 335-336
Author(s):  
Harold A. Johnson
Keyword(s):  
Large Sample ◽  
X Ray ◽  
Sample Chamber

Thermal quenching sample chamber for grazing incidence small angle x-ray scattering studies of polymer films

2007 ◽  
Vol 78 (11) ◽  
pp. 113910 ◽  
Author(s):  
M. A. Singh ◽  
M. N. Groves ◽  
M. S. Müller ◽  
I. J. Stahlbrand ◽  
D.-M. Smilgies
Keyword(s):  
Polymer Films ◽  
Small Angle ◽  
Thermal Quenching ◽  
Grazing Incidence ◽  
X Ray ◽  
X Ray Scattering ◽  
Sample Chamber ◽  
Ray Scattering

scholarly journals A new device to mount portable energy-dispersive X-ray fluorescence spectrometers (p-ED-XRF) for semi-continuous analyses of split (sediment) cores and solid samples

2017 ◽  
Vol 6 (1) ◽  
pp. 93-101 ◽  
Author(s):  
Philipp Hoelzmann ◽  
Torsten Klein ◽  
Frank Kutz ◽  
Brigitta Schütt
Keyword(s):  
Spatial Resolution ◽  
Atlantic Coast ◽  
Sediment Cores ◽  
Ccd Camera ◽  
Energy Dispersive ◽  
Solid Samples ◽  
Industrial Property ◽  
X Ray ◽  
New Device ◽  
Sample Chamber

Abstract. Portable energy-dispersive X-ray fluorescence spectrometers (p-ED-XRF) have become increasingly popular in sedimentary laboratories to quantify the chemical composition of a range of materials such as sediments, soils, solid samples, and artefacts. Here, we introduce a low-cost, clearly arranged unit that functions as a sample chamber (German industrial property rights no. 20 2014 106 048.0) for p-ED-XRF devices to facilitate economic, non-destructive, fast, and semi-continuous analysis of (sediment) cores or other solid samples. The spatial resolution of the measurements is limited to the specifications of the applied p-ED-XRF device – in our case a Thermo Scientific Niton XL3t p-ED-XRF spectrometer with a maximum spatial resolution of 0.3 cm and equipped with a charge-coupled device (CCD) camera to document the measurement spot. We demonstrate the strength of combining p-ED-XRF analyses with this new sample chamber to identify Holocene facies changes (e.g. marine vs. terrestrial sedimentary facies) using a sediment core from an estuarine environment in the context of a geoarchaeological investigation at the Atlantic coast of southern Spain.

Ternary Thallides REMgTl (Re = Y, La – Nd, Sm, Gd – Tm, Lu)

2005 ◽  
Vol 60 (3) ◽  
pp. 265-270 ◽  
Author(s):  
Rainer Kraft ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Rare Earth Metal ◽  
High Frequency ◽  
Three Dimensional ◽  
Earth Metal ◽  
X Ray ◽  
Sample Chamber ◽  
Trigonal Prismatic Coordination ◽  
Trigonal Prismatic

The rare earth metal (RE)-magnesium-thallides REMgTl (RE = Y, La-Nd, Sm, Gd-Tm, Lu) were prepared from the elements in sealed tantalum tubes in a water-cooled sample chamber of a high-frequency furnace. The thallides were characterized through their X-ray powder patterns. They crystallize with the hexagonal ZrNiAl type structure, space group P62m, with three formula units per cell. Four structures were refined from X-ray single crystal diffractometer data: α = 750.5(1), c = 459.85(8) pm, wR2 = 0.0491, 364 F2 values, 14 variables for YMgTl; α = 781.3(1), c = 477.84(8) pm, wR2 = 0.0640, BASF = 0.09(2), 425 F2 values, 15 variables for LaMgTl; α = 774.1(1), c = 473.75(7) pm, wR2 = 0.0405, 295 F2 values, 14 variables for CeMgTl; a = 760.3(1), c = 465.93(8) pm, wR2 = 0.0262, 287 F2 values, 14 variables for SmMgTl. The PrMgTl, NdMgTl, GdMgTl, TbMgTl, and DyMgTl structures have been analyzed using the Rietveld technique. The REMgTl structures contain two cystallographically independent thallium sites, both with tri-capped trigonal prismatic coordination: Tl1Mg3RE6 and Tl2Mg6RE3. Together the magnesium and thallium atoms form three-dimensional [MgTl] networks with Mg-Mg distances of 327 and Mg-Tl distances in the range 299 - 303 pm (data for CeMgTl)

scholarly journals Searching for fast extragalactic X-ray transients in Chandra surveys

2019 ◽  
Vol 487 (4) ◽  
pp. 4721-4736 ◽  
Author(s):  
G Yang (杨光) ◽  
W N Brandt ◽  
S F Zhu (朱世甫) ◽  
F E Bauer ◽  
B Luo (罗斌) ◽  
...  
Keyword(s):  
Event Rate ◽  
Large Population ◽  
Physical Nature ◽  
Effective Area ◽  
The Other ◽  
Field Of View ◽  
Stellar Objects ◽  
Large Sample ◽  
X Ray ◽  
Future Work

ABSTRACT Recent works have discovered two fast (≈10 ks) extragalactic X-ray transients in the Chandra Deep Field-South (CDF-S XT1 and XT2). These findings suggest that a large population of similar extragalactic transients might exist in archival X-ray observations. We develop a method that can effectively detect such transients in a single Chandra exposure, and systematically apply it to Chandra surveys of CDF-S, CDF-N, DEEP2, UDS, COSMOS, and E-CDF-S, totaling 19 Ms of exposure. We find 13 transient candidates, including CDF-S XT1 and XT2. With the aid of available excellent multiwavelength observations, we identify the physical nature of all these candidates. Aside from CDF-S XT1 and XT2, the other 11 sources are all stellar objects, and all of them have z-band magnitudes brighter than 20. We estimate an event rate of ${59^{+77}_{-38}\ \rm {evt\ yr^{-1}\, deg^{-2}}}$ for CDF-S XT-like transients with 0.5–7 keV peak fluxes log Fpeak ≳ −12.6 (erg cm−2 s−1). This event rate translates to ${\approx 15^{+20}_{-10}}$ transients existing among Chandra archival observations at Galactic latitudes |b| > 20°, which can be probed in future work. Future missions such as Athena and the Einstein Probe with large grasps (effective area × field of view) are needed to discover a large sample (∼thousands) of fast extragalactic X-ray transients.

Ternary Indides REMgIn (RE = Y, La–Nd, Sm, Gd–Tm, Lu). Synthesis, Structure and Magnetic Properties

2004 ◽  
Vol 59 (5) ◽  
pp. 513-518 ◽  
Author(s):  
Rainer Kraft ◽  
Martin Valldor ◽  
Daniel Kurowski ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Moments ◽  
Three Dimensional ◽  
Temperature Dependent ◽  
Variable Parameters ◽  
Magnetic Susceptibility Data ◽  
X Ray ◽  
Susceptibility Data ◽  
Sample Chamber ◽  
Trigonal Prismatic Coordination ◽  
Trigonal Prismatic

Abstract The equiatomic rare earth-magnesium-indium compounds REMgIn (RE = Y, La-Nd, Sm, Gd- Tm, Lu) were prepared from the elements in sealed tantalum tubes inside a water-cooled sample chamber of an induction furnace. All compounds were characterized through their X-ray powder patterns. They crystallize with the hexagonal ZrNiAl type structure, space group P6̄̄2m, with three formula units per cell. The structure of SmMgIn was refined from X-ray single crystal diffractometer data: a = 761.3(2), c = 470.3(1) pm, wR2 = 0.0429, 380 F2 values and 14 variable parameters. The DyMgIn, HoMgIn, and TmMgIn structures have been analyzed using the Rietveld technique. The REMgIn structures contain two cystallographically independent indium sites, both with tri-capped trigonal prismatic coordination: In1Sm6Mg3 and In2Mg6Sm3. Together the magnesium and indium atoms form a three-dimensional [MgIn] network with Mg-Mg distances of 320 and Mg-In distances in the range 294 - 299 pm. Temperature dependent magnetic susceptibility data show Curie-Weiss behavior for DyMgIn, HoMgIn, and TmMgIn with experimental magnetic moments of 11.0(1) μB/Dy atom, 10.9(1) μB/Ho atom, and 7.5(1) μB/Tm atom. The three compounds order antiferromagnetically at TN = 22(2) K (DyMgIn), 12(1) K (HoMgIn), and 3(1) K (TmMgIn).

A Complete Instrumental System for Energy Dispersive Diffractometry and Fluorescence Analysis

1971 ◽  
Vol 15 ◽  
pp. 254-265 ◽  
Author(s):  
G.W. Martin ◽  
A.S. Klein
Keyword(s):  
Fluorescence Analysis ◽  
Energy Dispersive ◽  
Strip Chart Recorder ◽  
X Ray ◽  
Strip Chart ◽  
Multichannel Analyzer ◽  
Digital Format ◽  
Chart Recorder ◽  
Instrumental System ◽  
Sample Chamber

A system, has been designed and tested for rapid energy dispersive diffractometry and simultaneous fluorescence analysis. A turntable composed of the sample chamber with attached air-cooled x-ray tube allows the 2θ angle to be varied with respect to the stationary Si(Li) detector. Data for most analyses can be obtained in one minute per sample. Results are stored in the memory of a multichannel analyzer and are read out on a CRT, strip chart recorder or tabulated in digital format by a computer.

Supermassive Black Hole Accretion History Inferred from a Large Sample of [ITAL]CHANDRA[/ITAL][ITAL]Chandra[/ITAL] Hard X-Ray Sources

2001 ◽  
Vol 122 (5) ◽  
pp. 2177-2189 ◽  
Author(s):  
A. J. Barger ◽  
L. L. Cowie ◽  
M. W. Bautz ◽  
W. N. Brandt ◽  
G. P. Garmire ◽  
...  
Keyword(s):  
Black Hole ◽  
Large Sample ◽  
X Ray ◽  
Supermassive Black Hole ◽  
Black Hole Accretion ◽  
Hole Accretion

scholarly journals X-ray Flare Rate of T Tauri Stars in Taurus

1995 ◽  
Vol 151 ◽  
pp. 216-217
Author(s):  
R. Neuhäuser ◽  
Th. Preibisch
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
T Tauri Stars ◽  
Medium Size ◽  
Late Type ◽  
Large Sample ◽  
X Ray ◽  
T Tauri ◽  
Sky Survey ◽  
Low Mass

AbstractWe study the X-ray emission of several hundred (young, low-mass, late-type, pre-main sequence) T Tauri stars (TTS) in the Taurus T association, a nearby well-studied region of ongoing star formation. We report on X-ray emission variability of TTS as observed with the flux-limited ROSAT All-Sky Survey (RASS). Since RASS observations are spatially unbiased, we can investigate the X-ray flare rate of TTS on a large sample. We find that large flares are very rare (once per year), while medium-size flares can occur once in ∼ 40 days.

scholarly journals X-Ray Emission from Non-Magnetic Cataclysmic Variables

1987 ◽  
Vol 93 ◽  
pp. 225-233
Author(s):  
H. Van Der Woerd
Keyword(s):  
Boundary Layer ◽  
Spectral Characteristics ◽  
Cataclysmic Variables ◽  
Large Sample ◽  
X Ray ◽  
Magnetic Cataclysmic Variables

AbstractEXOSAT observations of a large sample of non-magnetic cataclysmic variables have led to the detection of VW Hyi and OY Car as strong soft X-ray sources during superoutburst. The spectral characteristics of the X-ray emission of these SU Uma systems are compared. It is proposed that both systems have, besides a cool, optically thick boundary layer, an extended hot, optically thin corona.

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