Observations from the
            Hinotori
            mission

The satellite Hinotori was launched in 1981 by the Institute of Space and Astronautical Science of Japan. Two major experiments on board the Hinotori satellite were a hard X-ray imaging telescope with modulation collimators, and a high dispersion soft X-ray crystal spectrometer utilizing the Bragg diffraction of X-rays on quartz crystals. These two instruments have revealed for the first time that solar flares show varying characteristics depending on the environment of flaring regions, and that flares produce plasmas as hot as 3-4 x 10 7 K.

Download Full-text

Development of X-ray streak camera electronics at AWRE

Laser and Particle Beams ◽

10.1017/s0263034600001695 ◽

1986 ◽

Vol 4 (1) ◽

pp. 145-156 ◽

Cited By ~ 4

Author(s):

M. C. Jackson ◽

R. D. Long ◽

D. Lee ◽

N. J. Freeman

Keyword(s):

Streak Camera ◽

Sweep Rate ◽

Bragg Diffraction ◽

X Rays ◽

Crystal Spectrometer ◽

One Dimensional ◽

X Ray ◽

Ramp Generator ◽

Laser Facility ◽

User Facility

The paper reviews a number of X-ray streak cameras developed at AWRE. These cameras are used to provide temporal and one-dimensional spatial or spectral information on X-rays emitted from laser produced plasmas. Two of these cameras have been designed to be combined with other diagnostic instrumentation; one with a Wolter X-ray microscope (×22 magnification) and the other with a Bragg diffraction crystal spectrometer. This latter instrument provides a few eV spectral resolution and ∼15 ps temporal resolution; a typical experimental application at the AWRE HELEN laser facility will be described. The paper describes the circuitry of the bipolar avalanche transistor ramp generator used to drive the streak plates of the cameras. Improvements to this include: (a) increasing the fastest streak rate to ∼10 ps mm−1 by a distributed capacitance network across each of the bipolar stacks of transistors, and (b) reducing the trigger jitter to approximately ±10 ps by the use of a new mix of transistors in the stack and a Raytheon RS 3500 avalanche transistor. Additional improvements have now been added. These include a ‘half-scan’ user facility to aid initial camera timing and direct switching to select the sweep rate of the camera.

Download Full-text

NuSTAR reveals that the heavily obscured nucleus of NGC 2785 was the contaminant of IRAS 09104+4109 in the BeppoSAX/PDS hard X-rays

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833805 ◽

2018 ◽

Vol 619 ◽

pp. A16

Author(s):

C. Vignali ◽

P. Severgnini ◽

E. Piconcelli ◽

G. Lanzuisi ◽

R. Gilli ◽

...

Keyword(s):

X Rays ◽

X Ray ◽

Star Forming ◽

Physical Description ◽

Enhanced Sensitivity ◽

X Ray Imaging ◽

First Time ◽

In Virtue Of

Context. The search for heavily obscured active galactic nuclei has been revitalized in the last five years by NuSTAR, which has provided a good census and spectral characterization of a population of such objects, mostly at low redshift, thanks to its enhanced sensitivity above 10 keV compared to previous X-ray facilities, and its hard X-ray imaging capabilities. Aims. We aim at demonstrating how NGC 2785, a local (z = 0.009) star-forming galaxy, is responsible, in virtue of its heavily obscured active nucleus, for significant contamination in the non-imaging BeppoSAX/PDS data of the relatively nearby (≈17′) quasar IRAS 09104+4109 (z = 0.44), which was originally mis-classified as Compton thick. Methods. We analyzed ≈71 ks NuSTAR data of NGC 2785 using the MYTorus model and provided a physical description of the X-ray properties of the source for the first time. Results. We found that NGC 2785 hosts a heavily obscured (NH ≈ 3 × 1024 cm−2) nucleus. The intrinsic X-ray luminosity of the source, once corrected for the measured obscuration (L2−10keV ≈ 1042 erg s−1), is consistent within a factor of a few with predictions based on the source mid-infrared flux using widely adopted correlations from the literature. Conclusions. Based on NuSTAR data and previous indications from the Neil Gehrels Swift Observatory (BAT instrument), we confirm that NGC 2785, because of its hard X-ray emission and spectral shape, was responsible for at least one third of the 20–100 keV emission observed using the PDS instrument onboard BeppoSAX, originally completely associated with IRAS 09104+4109. Such emission led to the erroneous classification of this source as a Compton-thick quasar, while it is now recognized as Compton thin.

Download Full-text

First results of the STIX hard X-ray telescope onboard Solar Orbiter

10.5194/egusphere-egu21-4390 ◽

2021 ◽

Author(s):

Andrea Francesco Battaglia ◽

Jonas Saqri ◽

Ewan Dickson ◽

Hualin Xiao ◽

Astrid Veronig ◽

...

Keyword(s):

Solar Flares ◽

Magnetic Energy ◽

Imaging Spectroscopy ◽

X Rays ◽

X Ray ◽

X Ray Imaging ◽

First Results ◽

Early Peak ◽

Accelerated Particles ◽

Magnetic Energy Release

<p>With the launch and commissioning of Solar Orbiter, the Spectrometer/Telescope for Imaging X-rays (STIX) is the latest hard X-ray telescope to study solar flares over a large range of flare sizes. STIX uses hard X-ray imaging spectroscopy in the range from 4 to 150 keV to diagnose the hottest temperature of solar flare plasma and the related nonthermal accelerated electrons. The unique orbit away from the Earth-Sun line in combination with the opportunity of joint observations with other Solar Orbiter instruments, STIX will provide new inputs into understanding the magnetic energy release and particle acceleration in solar flares. Commissioning observations showed that STIX is working as designed and therefore we report on the first solar microflare observations recorded on June 2020, when the spacecraft was at 0.52 AU from the Sun. STIX&#8217;s measurements are compared with Earth-orbiting observatories, such as GOES and SDO/AIA, for which we investigate and interpret the different temporal evolution. The detected early peak of the STIX profiles relative to GOES is due either by nonthermal X-ray emission of accelerated particles interacting with the dense chromosphere or the higher sensitivity of STIX toward hotter plasma.</p>

Download Full-text

X-ray Imaging of Surface and Internal Structure

Advances in X-ray Analysis ◽

10.1154/s0376030800021819 ◽

1987 ◽

Vol 31 ◽

pp. 25-34

Author(s):

John C. Russ

Keyword(s):

Internal Structure ◽

Bragg Diffraction ◽

X Rays ◽

Widespread Application ◽

X Ray ◽

Study Materials ◽

X Ray Imaging ◽

Composition Variation ◽

Hospital Emergency Room

The most familiar result from X-ray analysis is a spectrum (on a chart recording or on film), or perhaps a short list of values (concentrations, d-spacings, etc.) taken from such a spectrum. X-ray pictures are usually associated in our minds with the hospital emergency room or the dentist's office. But images formed by X-rays are also an important tool to study materials' structures. Both conventional and unconventional uses of X-rays to study structural and compositional inhomogeneities find widespread application to materials. Applications include characterization of surface topography and composition variation, as well as internal structure. The methods make use of all types of X-ray interaction with materials, including Bragg diffraction and the fluorescence of characteristic X-rays, as well as simple X-ray attenuation due to absorption and scattering.

Download Full-text

On the Thermal Interpretation of Hard X-Ray Bursts from Solar Flares

Symposium - International Astronomical Union ◽

10.1017/s0074180900234554 ◽

1974 ◽

Vol 57 ◽

pp. 395-412 ◽

Cited By ~ 1

Author(s):

John C. Brown

Keyword(s):

Solar Flares ◽

Thermal Conduction ◽

Temperature Structure ◽

X Rays ◽

X Ray ◽

Time Variations ◽

Relationship Of ◽

First Time ◽

The Relationship ◽

Continuous Temperature

The possible validity of thermal bremsstrahlung models of flare hard X-ray bursts is investigated quantitatively. In particular, the problem of rapid thermal conduction in ‘multi-temperature’ models is adequately examined for the first time by using a continuous temperature distribution consistent with the observed X-ray spectrum. This distribution is obtained from a general analytic solution for the temperature structure required to mimick any ‘non-thermal’ spectrum, the method being equally applicable to cosmic sources.It is concluded that the thermal interpretation might extend to X-rays of hundreds of keV, a result with important consequences for flare energetics. The relationship of such a model to observations of X-ray polarization and rapid time variations is also considered.

Download Full-text

Defects of Platelet Function Recognized by X-Ray Imaging and Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100119806 ◽

1985 ◽

Vol 43 ◽

pp. 610-613

Author(s):

M.G. Baldini ◽

S. Morinaga ◽

D. Minasian ◽

R. Feder ◽

D. Sayre ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Cell Biology ◽

Imaging Technique ◽

Human Platelets ◽

X Rays ◽

X Ray ◽

X Ray Imaging ◽

Complex Phenomena ◽

Scanning Electron

Contact X-ray imaging is presently developing as an important imaging technique in cell biology. Our recent studies on human platelets have demonstrated that the cytoskeleton of these cells contains photondense structures which can preferentially be imaged by soft X-ray imaging. Our present research has dealt with platelet activation, i.e., the complex phenomena which precede platelet appregation and are associated with profound changes in platelet cytoskeleton. Human platelets suspended in plasma were used. Whole cell mounts were fixed and dehydrated, then exposed to a stationary source of soft X-rays as previously described. Developed replicas and respective grids were studied by scanning electron microscopy (SEM).

Download Full-text

Correction and verification of x-ray imaging crystal spectrometer analysis on Wendelstein 7-X through x-ray ray tracing

Review of Scientific Instruments ◽

10.1063/5.0043513 ◽

2021 ◽

Vol 92 (4) ◽

pp. 043530

Author(s):

N. A. Pablant ◽

A. Langenberg ◽

J. A. Alonso ◽

M. Bitter ◽

S. A. Bozhenkov ◽

...

Keyword(s):

Ray Tracing ◽

Crystal Spectrometer ◽

X Ray ◽

X Ray Imaging

Download Full-text

Observations of X-rays from Laboratory Sparks in Air at Atmospheric Pressure under Negative Switching Impulse Voltages

Atmosphere ◽

10.3390/atmos10040169 ◽

2019 ◽

Vol 10 (4) ◽

pp. 169 ◽

Cited By ~ 1

Author(s):

Mahbubur Rahman ◽

Pasan Hettiarachchi ◽

Vernon Cooray ◽

Joseph Dwyer ◽

Vladimir Rakov ◽

...

Keyword(s):

Rise Time ◽

Atmospheric Pressure ◽

Opposite Polarity ◽

X Rays ◽

X Ray ◽

Impulse Voltage ◽

First Time ◽

Switching Impulses ◽

Low Rate

We present observations of X-rays from laboratory sparks created in the air at atmospheric pressure by applying an impulse voltage with long (250 µs) rise-time. X-ray production in 35 and 46 cm gaps for three different electrode configurations was studied. The results demonstrate, for the first time, the production of X-rays in gaps subjected to switching impulses. The low rate of rise of the voltage in switching impulses does not significantly reduce the production of X-rays. Additionally, the timing of the X-ray occurrence suggests the possibility that the mechanism of X-ray production by sparks is related to the collision of streamers of opposite polarity.

Download Full-text

Mesoscopic structure of SiC fibers by neutron and x-ray scattering

Journal of Materials Research ◽

10.1557/jmr.1996.0151 ◽

1996 ◽

Vol 11 (5) ◽

pp. 1169-1178 ◽

Cited By ~ 7

Author(s):

Kentaro Suzuya ◽

Michihiro Furusaka ◽

Noboru Watanabe ◽

Makoto Osawa ◽

Kiyohito Okamura ◽

...

Keyword(s):

Neutron Scattering ◽

Volume Fraction ◽

X Rays ◽

X Ray ◽

Sic Fibers ◽

X Ray Scattering ◽

Mesoscopic Structure ◽

Angle Scattering ◽

Momentum Transfer Range ◽

First Time

Mesoscopic structures of SiC fibers produced from polycarbosilane by different methods were studied by diffraction and small-angle scattering of neutrons and x-rays. Microvoids of a size of 4–10 Å in diameter have been observed for the first time by neutron scattering in a medium momentum transfer range (Q = 0.1–1.0 Å−1). The size and the volume fraction of β–SiC particles were determined for fibers prepared at different heat-treatment temperatures. The results show that wide-angle neutron scattering measurements are especially useful for the study of the mesoscopic structure of multicomponent materials.

Download Full-text