scholarly journals ESA’s X-Ray Astronomy Mission, XMM

1990 ◽  
Vol 123 ◽  
pp. 129-140
Author(s):  
B.G. Taylor ◽  
A. Peacock
Keyword(s):  
Resolving Power ◽  
Science Program ◽  
Eccentric Orbit ◽  
Ccd Cameras ◽  
Optical Telescope ◽  
X Ray ◽  
Medium Resolution ◽  
Reflection Gratings ◽  
Better Than

AbstractESA’s X-ray Astronomy Mission, XMM, scheduled for launch in 1998, is the second of four cornerstones of ESA’s long term science program Horizon 2000. Covering the range from about 0.1 to 10 keV, it will provide a high throughput of 5000 cm2 at 7 keV with three independant telescopes, and have a spatial resolution better than 30 arcsec. Broadband spectrophotometry is provided by CCD cameras while reflection gratings provide medium resolution spectroscopy (resolving power of about 400) in the range 0.3–3 keV. Long uninterrupted observations will be made from the 24 hr period, highly eccentric orbit, reaching a sensitivity approaching 10−15 erg cm−2 s−1 in one orbit. A 30 cm UV/optical telescope is bore-sighted with the x-ray telescopes to provide simultaneous optical counterparts to the numerous serendipitous X-ray sources which will be detected during every observation.

scholarly journals Liquid flexRIXS: A RIXS endstation for molecular systems at BESSY II

2016 ◽  
Vol 2 ◽  
Author(s):  
Annette Pietzsch
Keyword(s):  
Gas Flow ◽  
Flow Cell ◽  
Resolving Power ◽  
Liquid Jet ◽  
X Ray ◽  
Molecular Systems ◽  
X Ray Scattering ◽  
Liquid Samples ◽  
Better Than ◽  
Ray Scattering

The liquid flexRIXS endstation is dedicated to resonant inelastic x-ray scattering experiments on liquid samples and gasses in the soft x-ray range. The liquids are injected into the chamber via a liquid jet system whereas gasses and also small amounts of liquids can be investigated using a liquid/gas flow cell. The MCP-based RIXS spectrometer allows for a resolving power of better than 1000.

Pozzolanic Reaction of Supplementary Cementitious Materials and Its Effects on the Strength of Mass Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 505-511 ◽  
Author(s):  
Hua Shan Yang ◽  
Kun He Fang ◽  
Sheng Jin Tu
Keyword(s):  
Cementitious Materials ◽  
Pozzolanic Reaction ◽  
Supplementary Cementitious Materials ◽  
Mass Concrete ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slag Powder ◽  
Phosphorous Slag ◽  
Better Than

The present study aims to investigate the opportunity to largely substitute low heat Portland cement of mass concrete with supplementary cementitious materials. The pozzolanic reaction of two types of supplementary cementitious materials, phosphorous slag powder and fly ash , were determined by X-ray diffraction, differential thermal analysis–thermogravimetry and scanning electron microscopy from 28 to 90 days. The properties of mortar and mass concrete containing 30% of supplementary cementitious materials were also investigated. Results showed that supplementary cementitious materials could decrease the amount of calcium hydroxide, fill the capillary pores, thus making the mortar and mass concrete more compact and durable. Long-term strength of mass concrete containing 30% of supplementary cementitious materials were comparable (or even better) than the control concrete (without supplementary cementitious materials) at constant workability, while the Young’s modulus was lower than the control concrete.

scholarly journals Gamma-Ray Orbital Modulation of the Transitioning Millisecond Pulsar Binary XSS J12270–4859

2022 ◽  
Vol 924 (2) ◽  
pp. 91
Author(s):  
Hongjun An
Keyword(s):  
Gamma Ray ◽  
Optical Data ◽  
Large Area ◽  
Time Intervals ◽  
Optical Telescope ◽  
X Ray ◽  
Low Mass ◽  
Orbital Modulation ◽  
Short Time

Abstract We report on gamma-ray orbital modulation of the transitioning MSP binary XSS J12270–4859 detected in the Fermi Large Area Telescope (LAT) data. We use long-term optical data taken with the XMM-Newton OM and the Swift UltraViolet Optical Telescope to inspect radio timing solutions that are limited to relatively short time intervals and find that extrapolation of the solutions aligns well with the phasing of the optical data over 15 yr. The Fermi-LAT data folded on the timing solutions exhibit significant modulation (p = 5 × 10−6) with a gamma-ray minimum at the inferior conjunction of the pulsar. Intriguingly, the source seems to show similar modulation in both the low-mass X-ray binary and the MSP states, implying that mechanisms for gamma-ray emission in the two states are similar. We discuss these findings and their implications using an intrabinary shock scenario.

On the advantages of operation in second-order diffraction of blazed gratings in soft X-ray monochromators

2019 ◽  
Vol 26 (5) ◽  
pp. 1587-1591
Author(s):  
Werner Jark
Keyword(s):  
Synchrotron Radiation ◽  
Systematic Study ◽  
Second Order ◽  
Resolving Power ◽  
X Rays ◽  
X Ray ◽  
Order Diffraction ◽  
Reflection Gratings ◽  
Grazing Angles ◽  
Sawtooth Profile

The fact that a diffraction grating can provide twofold-smaller bandwidth when operated in second-order diffraction is long known and applied routinely in the laboratory for spectroscopy in the visible and ultraviolet spectral range. A similar routine operation in monochromators for the soft X-ray range is not reported yet. This study will thus address the feasibility of efficient diffraction of soft X-rays in the second order at reflection gratings when operated at grazing angles of incidence. The related systematic study could make profitable use of a recently introduced simple analytical equation for the prediction of the diffraction efficiency of blazed gratings with an ideal sawtooth profile. The predictions are then verified by use of rigorous calculations. The principle finding is that, by operation of gratings with lower groove densities, and thus with higher efficiencies, in higher order diffraction, one can extend the tuning in existing instruments with mechanical/optical limitations to larger photon energies. The performance in terms of transmission and spectral resolving power can be very similar to the performance of a grating with a larger groove density, which would otherwise have to be used for accessing the same energy range. This would allow operation of a single highly efficient grating over a larger photon energy interval at a modern synchrotron radiation source, e.g. from 0.3 to 2.2 keV. Without any requirement for a sophisticated grating exchange scheme, a related instrument promises to be sufficiently stable for the needs imposed by the improvements in source point stability at diffraction-limited storage rings.

Plane-Polarized, Two-Crystal X-Ray Spectrometer

1965 ◽  
Vol 9 ◽  
pp. 251-258
Author(s):  
Raymond J. Donahue ◽  
Leonid V. Azároff
Keyword(s):  
Experimental Tests ◽  
Dynamical Theory ◽  
Resolving Power ◽  
X Ray Diffraction ◽  
Germanium Crystal ◽  
Full Agreement ◽  
Crystal Spectrometer ◽  
X Ray ◽  
Better Than

AbstractA two-crystal spectrometer employing a Cole polarizer made from a germanium crystal as one of the crystals is described. Experimental tests show that placing the polarizer crystal in the second position markedly improves the degree of plane polarisation, in full agreement with the predictions of the dynamical theory of X-ray diffraction. Tests indicate that the twice-diffracted beam h better than 95% plane polarized. The angular resolving power of the instrument is comparable to that of conventional two-crystal spectrometers. The almost wholly planepolarized monochromatic X-radiation, moreover, permits certain tests to be carried out far more effectively than is possible with partly polarized X-ray beams.

Coordination Analysis by High Resolution X-ray Spectroscopy*

1984 ◽  
Vol 28 ◽  
pp. 45-52 ◽  
Author(s):  
You-Zhao Bai ◽  
Sei Fukushima ◽  
Yohichi Gohshi
Keyword(s):  
High Resolution ◽  
Energy Dispersive ◽  
Resolving Power ◽  
Low Resolution ◽  
X Ray ◽  
Medium Resolution ◽  
Crystal Dispersion ◽  
Scanning Mechanism ◽  
Very High

Various X-ray fluorescence spectrometers are now commercially available, and these spectrometers are classified into two categories, i.e., energy dispersive and wavelength dispersive (Table 1). Energy dispersive instruments are of low resolution. Wavelength dispersive instruments are often referred to as high resolution. However, commercially available wavelength dispersive instruments are usually equipped with a one-crystal dispersion unit. Therefore, to be more precise, these instruments could be called medium resolution apparatuses. There are other types of spectrometers which are two- or three-crysral spectrometers, and which are known to have very high resolving power. High resolution X-ray fluorescence spectrometers, however, have rarely been constructed. This is because this type of spectrometer needs a very precise and complicated scanning mechanism, and also because the intensity of X-ray fluorescence is often lost.

scholarly journals Quest for the Upcoming Periastron Passage of an Episodic Dust Maker and Particle-accelerating Colliding-wind Binary: WR 125

2021 ◽  
Vol 162 (6) ◽  
pp. 257
Author(s):  
Bharti Arora ◽  
J. C. Pandey ◽  
Michaël De Becker ◽  
S. B. Pandey ◽  
Nand K. Chakradhari ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Recurrence Time ◽  
Time Interval ◽  
Wide Field ◽  
X Rays ◽  
Optical Telescope ◽  
X Ray ◽  
Enhanced Absorption

Abstract We have carried out a long-term infrared and X-ray investigation of the colliding-wind binary WR 125 (WC7 + O9III). The source was monitored using AstroSat Soft X-ray Telescope and the Tata Institute of Fundamental Research Near Infrared Imaging Camera-II mounted at the back of 3.6 m Devasthal Optical Telescope. WR 125 appeared brighter in the near-infrared K-band during the years 2017–2021 which is attributed to another episode of dust formation similar to the one reported during the likely periastron passage at the beginning of the 1990s. This is further supported by enhanced emission observed in the W1 and W2 bands of Wide-field Infrared Survey Explorer from 2018–2019. By combining archival X-ray data sets with our new measurements, long-term variations have been noticed. The source reaches a lower emission state in 2020 June (close to the recent infrared maximum) which could be due to enhanced absorption of X-rays produced in the colliding-wind region by the WC stellar wind close to the periastron in an eccentric orbit. The time interval between the previous and latest X-ray low states may indicate an orbital period of 28–29 years, in fair agreement with the recurrence time of episodic dust production. We also discuss published radio measurements in the context of a common picture based on a long-period binary scenario. These results allow us to draw relevant guidelines for future multiwavelength observations of WR 125.

Development of fluorescent probes for x-ray microscopy

1994 ◽  
Vol 52 ◽  
pp. 48-49
Author(s):  
M. M. Moronne ◽  
C. Larabell ◽  
P. R. Selvin ◽  
A. I. von Brenndorff
Keyword(s):  
Visible Light ◽  
Resolving Power ◽  
New Techniques ◽  
X Ray ◽  
Staining Techniques ◽  
Synchrotron Light ◽  
Light Fluorescence ◽  
20 Nm ◽  
Near Future ◽  
Better Than

It is only in the last few years that the complimentary development of high resolution zone plate lenses and intense, tunable, monochromatic x-ray sources has made possible the construction of soft x-ray microscopes with high resolving power. Both scanning and imaging microscopes have been produced that are capable of better than 50 nm resolution, with improvements expected to reach 20 nm in the near future. Although innovative new techniques are being explored for recognizing the unique x-ray signatures of intrinsic cellular biochemical constituents at the high resolutions provided by soft x-ray microscopes, little has been done to develop specific labeling or staining techniques. Development of such methods are important to be able to assign structure-function relationships, and to identify subcellular structures that are otherwise hidden by excess image contrast, as in the case of thick specimens.In this context, Jacobsen et al (1993) have demonstrated that an x-ray microprobe such as that provided by the scanning x-ray microscope (STXM) at the National Synchrotron Light Source (NSLS) can excite visible light fluorescence in phosphor beads and fluorochrome labeled latex spheres. Importantly, the resolution of such a system is set by the size of the x-ray beam spot and not by the wavelength of the emitted visible light.

scholarly journals The 35-Day Cycle of Hercules X-1 in Multiple Energy Bands from MAXI and Swift/BAT Monitoring

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 160
Author(s):  
Denis Leahy ◽  
Yuyang Wang
Keyword(s):  
Energy Dependence ◽  
Column Density ◽  
Cross Correlation ◽  
Light Curves ◽  
Energy Bands ◽  
X Ray ◽  
Turn On ◽  
Cycle Lengths ◽  
Better Than

Hercules X-1 (Her X-1) has been monitored by MAXI and by Swift/BAT for over a decade. Those observations are analyzed to measure the shape and energy dependence of the long-term average of the 35-day cycle of Her X-1. The cross-correlation (CC) method is used to determine peak times and cycle lengths. Swift/BAT data produces better 35-day times because of the gaps in the MAXI data. Using Swift/BAT-derived times, average 35-day cycle light-curves are created for multiple energy bands: MAXI’s 2–20 keV, 2–4 keV, 4–10 keV and 10–20 keV bands and Swift/BAT’s 15–50 keV band. The durations of the different states of the 35-day cycle are measured better than previously. We find clear changes in X-ray softness ratio with 35-day phase, and detect persistent features in the 35-day cycle. These include column density changes during turn-on of Main High and of Short High states, and persistent absorption dips during the bright part of Main High and of Short High states.

Commissioning and first results of the LNLS XAFS beamline

1998 ◽  
Vol 5 (3) ◽  
pp. 521-523 ◽  
Author(s):  
H. Tolentino ◽  
J. C. Cezar ◽  
D. Z. Cruz ◽  
V. Compagnon-Cailhol ◽  
E. Tamura ◽  
...  
Keyword(s):  
Full Range ◽  
Resolving Power ◽  
Photon Flux ◽  
Vertical Position ◽  
Double Crystal ◽  
X Ray ◽  
First Results ◽  
Set Up ◽  
X Ray Absorption ◽  
Better Than

An X-ray absorption fine-structure spectroscopy beamline has been installed and commissioned at a bending-magnet source at LNLS. Three monochromators are available: a channel-cut, a double-crystal and a four-crystal set-up. They have been operated from 2500 up to 15000 eV, with a resolving power better than 5500 in the full range. Photon flux of the order of 108 photons s−1 up to 1010 photons s−1 has been attained. The experimental station is equipped with a table that can withstand a weight of 300 kg and track the vertical position of the beam with a 2.5 µm accuracy over a 120 mm stroke. The beamline has been fully characterized and the first results are presented.

Sign in / Sign up

Export Citation Format

Share Document