A focusing X-ray telescope for use in the study of extraterrestrial X-ray sources in the energy range 20–140 keV

1968 ◽  
Vol 46 (10) ◽  
pp. S1103-S1106 ◽  
Author(s):  
T. R. Llndquist ◽  
W. R. Webber
Keyword(s):  
Energy Range ◽  
Rock Salt ◽  
Angular Resolution ◽  
X Rays ◽  
Effective Energy ◽  
Optimum Thickness ◽  
Bragg Condition ◽  
X Ray ◽  
Area Efficiency ◽  
Salt Crystals

We have designed and tested a focusing X-ray telescope with an angular resolution (FWHM) of 1.0° for the study of extraterrestrial X-ray sources in the energy range 20–140 keV. The telescope's lens is an array of rock salt crystals (each of which is approximately one inch square), mounted on a 6-ft-diameter paraboloidal frame. The lens is located 9.5 ft above a 2-in.-diameter NaI crystal and PM tube (which measures the energy of the incident X ray). X rays passing through the salt crystals undergo a 2θ deflection if the Bragg condition for reflection, nλ = 2d sin θ, is approximately satisfied. Optimum thickness and effective energy bandwidths for such reflections have been determined for energies in the telescope's operating range. The area-efficiency product of the lens is approximately 8 times the NaI crystal area from 20 to 40 keV, giving a real improvement in the signal-to-background ratio. Crystals more nearly perfect than rock salt offer the possibility of increased gain over narrow energy intervals. Polarization measurements of the incident X rays may also be made.

scholarly journals An X-ray study of the heat motions of the atoms in a rock-salt crystal

1927 ◽  
Vol 117 (776) ◽  
pp. 62-87 ◽  
Keyword(s):  
Fourier Analysis ◽  
Rock Salt ◽  
Low Temperatures ◽  
X Rays ◽  
Salt Crystal ◽  
X Ray ◽  
Salt Crystals ◽  
Different Temperatures ◽  
Atomic Scattering ◽  
Actual Amplitude

1. The present paper may be divided into two parts. In the first, some experiments on the intensity of reflexion of X-rays by rock-salt crystals at low temperatures are described. The results of these experiments, when combined with data obtained previously at high temperatures, are compared with the theoretical formulæ of Debye and Waller for the temperature factor of X-ray reflexion. In the second part of the paper we have attempted to get some idea of the actual amplitude of the heat-motions of the atoms in the rock-salt lattice, by analysing the F curves, or curves showing the variation of the atomic scattering power with angle of scattering, using the method of Fourier analysis introduced by Duane and Havighurst, so as to obtain the distribution of electrons in the crystal unit at different temperatures. In connection with this work a new set of absolute determinations of intensity of reflexion has been made, and, from these, the F factors at different temperatures have been calculated, using the results of the experiments described in the first part of the paper.

scholarly journals X-Ray Spectrometry of Galactic Sources in the Energy Range 30–200 keV

1971 ◽  
Vol 41 ◽  
pp. 168-179
Author(s):  
A Bui-Van ◽  
G. Vedrenne ◽  
Y. Cezac ◽  
A. Bouigue ◽  
L. Sabaud
Keyword(s):  
Energy Range ◽  
Angular Resolution ◽  
X Rays ◽  
Balloon Flight ◽  
X Ray ◽  
Flux Limit ◽  
Galactic Sources ◽  
Detection Unit

We describe a detection unit for X-rays in the energy range 30-200 keV of high directivity (2° FWHM). This directivity is obtained by the use of a honeycomb collimator and completed by an efficient passive shielding. The angular resolution of the detector necessitates the use of a solar sensor so as to track the sources observed during the balloon flight and to localize them with an accuracy of 3.8 arc min. This experiment was launched with balloon at Aire-sur-L'Adour and Gap (France) and the results obtained must permit the flux limit detected to be reduced.The performances of this detector are analysed as well as their consequences in the study of galactic discrete sources.

scholarly journals An investigation into the existence of zero-point energy in the Rock-Salt Lattice by an X-Ray Diffraction Method

1928 ◽  
Vol 118 (779) ◽  
pp. 334-350 ◽  
Keyword(s):  
Rock Salt ◽  
Diffraction Method ◽  
Zero Point ◽  
Temperature Factor ◽  
X Rays ◽  
Zero Point Energy ◽  
Chlorine Atoms ◽  
Point Energy ◽  
X Ray ◽  
State Of Rest

In the present paper we shall attempt to collate the results of four separate lines of research which, taken together, appear to provide some interesting checks between theory and experiment. The investigations to be considered are (1) the discussion by Waller* and by Wentzel,† on the basis of the quantum (wave) mechanics, of the scattering of radiation by an atom ; (2) the calculation by Hartree of the Schrödinger distribution of charge in the atoms of chlorine and sodium ; (3) the measurements of James and Miss Firth‡ of the scattering power of the sodium and chlorine atoms in the rock-salt crystal for X-rays at a series of temperatures extending as low as the temperature of liquid air ; and (4) the theoretical discussion of the temperature factor of X-ray reflexion by Debye§ and by Waller.∥ Application of the laws of scattering to the distribution of charge calculated for the sodium and chlorine atoms, enables us to calculate the coherent atomic scattering for X-radiation, as a function of the angle of scattering and of the wave-length, for these atoms in a state of rest, assuming that the frequency of the X-radiation is higher than, and not too near the frequency of the K - absorption edge for the atom.¶ From the observed scattering power at the temperature of liquid air, and from the measured value of the temperature factor, we can, by applying the theory of the temperature effect, calculate the scattering power at the absolute zero, or rather for the atom reduced to a state of rest. The extrapolation to a state of rest will differ according to whether we assume the existence or absence of zero point energy in the crystal lattice. Hence we may hope, in the first place to test the agreement between the observed scattering power and that calculated from the atomic model, and in the second place to see whether the experimental results indicate the presence of zero-point energy or no.

THE AGILE MISSION AND GAMMA-RAY ASTROPHYSICS

2002 ◽  
Vol 17 (12n13) ◽  
pp. 1799-1808 ◽  
Author(s):  
MARCO TAVANI
Keyword(s):  
Energy Range ◽  
Gamma Ray ◽  
Angular Resolution ◽  
Source Monitoring ◽  
Space Mission ◽  
Quick Response ◽  
Scientific Program ◽  
X Ray ◽  
Imaging Capability ◽  
Gamma Ray Imaging

Gamma-ray astrophysics in the energy range between 30 MeV and 30 GeV is in desperate need of arcminute angular resolution and source monitoring capability. The AGILE Mission planned to be operational in 2004-2006 will be the only space mission entirely dedicated to gamma-ray astrophysics above 30 MeV. The main characteristics of AGILE are the simultaneous X-ray and gamma-ray imaging capability (reaching arcminute resolution) and excellent gamma-ray timing (10-100 microseconds). AGILE scientific program will emphasize a quick response to gamma-ray transients and multiwavelength studies of gamma-ray sources.

scholarly journals PHEMTO: the polarimetric high energy modular telescope observatory

2021 ◽  
Author(s):  
P. Laurent ◽  
F. Acero ◽  
V. Beckmann ◽  
S. Brandt ◽  
F. Cangemi ◽  
...  
Keyword(s):  
Black Holes ◽  
Energy Range ◽  
High Performance ◽  
Angular Resolution ◽  
High Energy ◽  
Thermal Processes ◽  
Scientific Performance ◽  
X Ray ◽  
Measurement Capability ◽  
Better Than

AbstractBased upon dual focusing techniques, the Polarimetric High-Energy Modular Telescope Observatory (PHEMTO) is designed to have performance several orders of magnitude better than the present hard X-ray instruments, in the 1–600 keV energy range. This, together with its angular resolution of around one arcsecond, and its sensitive polarimetry measurement capability, will give PHEMTO the improvements in scientific performance needed for a mission in the 2050 era in order to study AGN, galactic black holes, neutrons stars, and supernovae. In addition, its high performance will enable the study of the non-thermal processes in galaxy clusters with an unprecedented accuracy.

scholarly journals The XXL Survey

2018 ◽  
Vol 620 ◽  
pp. A18 ◽  
Author(s):  
C. H. A. Logan ◽  
B. J. Maughan ◽  
M. N. Bremer ◽  
P. Giles ◽  
M. Birkinshaw ◽  
...  
Keyword(s):  
Angular Resolution ◽  
False Positive Rate ◽  
High Sensitivity ◽  
Point Sources ◽  
Selection Function ◽  
X Rays ◽  
Cluster Emission ◽  
X Ray ◽  
Wide Range ◽  
Function Modelling

Context. The XMM-XXL survey has used observations from the XMM-Newton observatory to detect clusters of galaxies over a wide range in mass and redshift. The moderate PSF (FWHM ~ 6″ on-axis) of XMM-Newton means that point sources within or projected onto a cluster may not be separated from the cluster emission, leading to enhanced luminosities and affecting the selection function of the cluster survey. Aims. We present the results of short Chandra observations of 21 galaxy clusters and cluster candidates at redshifts z > 1 detected in the XMM-XXL survey in X-rays or selected in the optical and infra-red. Methods. With the superior angular resolution of Chandra, we investigate whether there are any point sources within the cluster region that were not detected by the XMM-XXL analysis pipeline, and whether any point sources were misclassified as distant clusters. Results. Of the 14 X-ray selected clusters, 9 are free from significant point source contamination, either having no previously unresolved sources detected by Chandra or with less than about 10% of the reported XXL cluster flux being resolved into point sources. Of the other five sources, one is significantly contaminated by previously unresolved AGN, and four appear to be AGN misclassified as clusters. All but one of these cases are in the subset of less secure X-ray selected cluster detections and the false positive rate is consistent with that expected from the XXL selection function modelling. We also considered a further seven optically selected cluster candidates associated with faint XXL sources that were not classed as clusters. Of these, three were shown to be AGN by Chandra, one is a cluster whose XXL survey flux was highly contaminated by unresolved AGN, while three appear to be uncontaminated clusters. By decontaminating and vetting these distant clusters, we provide a pure sample of clusters at redshift z > 1 for deeper follow-up observations, and demonstrate the utility of using Chandra snapshots to test for AGN in surveys with high sensitivity but poor angular resolution.

scholarly journals NSLS-II MX beamlines FMX for micro-crystallography & AMX for highly automated MX

2014 ◽  
Vol 70 (a1) ◽  
pp. C1733-C1733
Author(s):  
Martin Fuchs ◽  
Robert Sweet ◽  
Lonny Berman ◽  
Dileep Bhogadi ◽  
Wayne Hendrickson ◽  
...  
Keyword(s):  
Energy Range ◽  
Structure Determination ◽  
Optical Systems ◽  
Photon Flux ◽  
X Rays ◽  
Macromolecular Crystallography ◽  
Binding Studies ◽  
X Ray ◽  
Array Detectors ◽  
Broad Energy Range

We present the final design of the x-ray optical systems and experimental stations of the two macromolecular crystallography (MX) beamlines, FMX and AMX, at the National Synchrotron Light Source-II (NSLS-II). Along with its companion x-ray scattering beamline, LIX, this suite of Advanced Beamlines for Biological Investigations with X-rays (ABBIX, [1]) will begin user operation in 2016. The pair of MX beamlines with complementary and overlapping capabilities is located at canted undulators (IVU21) in sector 17-ID. The Frontier Microfocusing Macromolecular Crystallography beamline (FMX) will deliver a photon flux of ~5x10^12 ph/s at a wavelength of 1 Å into a spot of 1 - 50 µm size. It will cover a broad energy range from 5 - 30 keV, corresponding to wavelengths from 0.4 - 2.5 Å. The highly Automated Macromolecular Crystallography beamline (AMX) will be optimized for high throughput applications, with beam sizes from 4 - 100 µm, an energy range of 5 - 18 keV (0.7 - 2.5 Å), and a flux at 1 Å of ~10^13 ph/s. Central components of the in-house-developed experimental stations are a 100 nm sphere of confusion goniometer with a horizontal axis, piezo-slits to provide dynamic beam size changes during diffraction experiments, a dedicated secondary goniometer for crystallization plates, and sample- and plate-changing robots. FMX and AMX will support a broad range of biomedical structure determination methods from serial crystallography on micron-sized crystals, to structure determination of complexes in large unit cells, to rapid sample screening and data collection of crystals in trays, for instance to characterize membrane protein crystals and to conduct ligand-binding studies. Together with the solution scattering program at LIX, the new beamlines will offer unique opportunities for advanced diffraction experiments with micro- and mini-beams, with next generation hybrid pixel array detectors and emerging crystal delivery methods such as acoustic droplet ejection. This work is supported by the US National Institutes of Health.

A scanning transmission X-ray microscope at the Pohang Light Source

2018 ◽  
Vol 25 (3) ◽  
pp. 878-884 ◽  
Author(s):  
Hyun-Joon Shin ◽  
Namdong Kim ◽  
Hee-Seob Kim ◽  
Wol-Woo Lee ◽  
Chae-Soon Lee ◽  
...  
Keyword(s):  
Energy Range ◽  
Light Source ◽  
Photon Energy ◽  
Chemical State ◽  
Photon Energy Range ◽  
X Rays ◽  
X Ray ◽  
Space Resolution ◽  
Scanning Transmission ◽  
Pohang Light Source

A scanning transmission X-ray microscope is operational at the 10A beamline at the Pohang Light Source. The 10A beamline provides soft X-rays in the photon energy range 100–2000 eV using an elliptically polarized undulator. The practically usable photon energy range of the scanning transmission X-ray microscopy (STXM) setup is from ∼150 to ∼1600 eV. With a zone plate of 25 nm outermost zone width, the diffraction-limited space resolution, ∼30 nm, is achieved in the photon energy range up to ∼850 eV. In transmission mode for thin samples, STXM provides the element, chemical state and magnetic moment specific distributions, based on absorption spectroscopy. A soft X-ray fluorescence measurement setup has been implemented in order to provide the elemental distribution of thicker samples as well as chemical state information with a space resolution of ∼50 nm. A ptychography setup has been implemented in order to improve the space resolution down to 10 nm. Hardware setups and application activities of the STXM are presented.

scholarly journals Iron Line Emission from NGC1068

1989 ◽  
Vol 134 ◽  
pp. 167-172
Author(s):  
Katsuji Koyama
Keyword(s):  
Energy Range ◽  
Power Law ◽  
Equivalent Width ◽  
Line Emission ◽  
X Rays ◽  
Iron Line ◽  
X Ray ◽  
Central Engine ◽  
Photon Index ◽  
The Continuum

X-ray emission in the 2–10 keV energy range was observed with the Ginga satellite from the Seyfert 2 galaxy NGC1068. The continuum spectrum can be described by a power-law of photon index about 1.5. An intense iron line at 6.5 keV with an equivalent width of 1.3 keV was clearly noticed. The X-ray flux was about 6 × 10 −12 erg/sec/cm2 or 3 × 1041 erg/sec, assuming a distance of 22 Mpc. The observed spectrum is consistent with the scattering and reprocessing of X-rays by the gas surrounding the central engine. With this picture we estimate that the X-ray flux of the central engine is about 1043 - 1044 erg/sec, a typical value for a Seyfert 1 galaxy.

Electron Channeling X-ray Microanalysis for Cation Configuration in Irradiated Magnesium Aluminate Spinel

1999 ◽  
Vol 589 ◽  
Author(s):  
S. Matsumura ◽  
T. Soeda ◽  
N. J. Zaluzec ◽  
C. Kinoshita
Keyword(s):  
Angular Resolution ◽  
Magnesium Aluminate ◽  
High Angular Resolution ◽  
X Rays ◽  
Magnesium Aluminate Spinel ◽  
X Ray ◽  
Electron Channeling ◽  
Resolution Electron ◽  
Practical Tool ◽  
Cation Arrangement

AbstractHigh angular resolution electron channeling x-ray spectroscopy (HARECXS) was examined as a practical tool to locate lattice-ions in spinel crystals. The orientation dependent intensity distribution of emitted x-rays obtained by HARECXS is so sensitive to lattice-ion configuration in the illuminated areas that the occupation probabilities on specific positions in the crystal lattice can be determined accurately through comparison with the theoretical rocking curves. HARECXS measurements have revealed partially disordered cation arrangement in MgO·nAl2O3 with n= 1.0 and 2.4. Most A13+ lattice-ions occupy the octahedral (VI) sites with 6-fold coordination, while Mg2+ lattice-ions reside on both the tetrahedral (IV) and the octahedral (VI) sites. The structural vacancies are enriched in the IV-sites. Further evacuation of cations from the IV-sites to the VI-sites is recognized in a disordering process induced by irradiation with 1 MeV Ne+ ions up to 8.9 dpa at 870 K.

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