Miniature Filament Eruptions and their Reconnections in X-Ray Jets: Evidence for a New Paradigm

Science.gov (United States)

Sterling, Alphonse C.; Moore, Ronald L.; Falconer, David A.

2014-01-01

We investigate the onset of approximately10 random X-ray jets observed by Hinode/XRT. Each jet was near the limb in a polar coronal hole, and showed a ``bright point'' in an edge of the base of the jet, as is typical for previously-observed X-ray jets. We examined SDO/AIA EUV images of each of the jets over multiple AIA channels, including 304 Ang, which detects chromospheric emissions, and 171, 193, and 211 Ang, which detect cooler-coronal emissions. We find the jets to result from eruptions of miniature (size less than approximately 10 arcsec) filaments from the bases of the jets. Much of the erupting-filament material forms a chromospheric-temperature jet. In the cool-coronal channels, often the filament appears in absorption and the jet in emission. The jet bright point forms at the location from which the miniature filament is ejected, analogous to the formation of a standard solar flare in the wake of the eruption of a typical larger-scale chromospheric filament. Thus these X-ray jets and their bright points are made by miniature filament eruptions. They are evidently produced the same way as an on-disk coronal jet we observed in Adams et al. (2014); that on-disk jet had no obvious emerging magnetic field in its base. We conclude that, for many jets, the standard idea of X-ray jets forming from reconnection between emerging flux and preexisting coronal field is incorrect. ACS and RLM were supported by funding from NASA/LWS, Hinode, and ISSI.

First hard X-ray detection of the non-thermal emission around the Arches cluster: morphology and spectral studies with NuSTAR

DEFF Research Database (Denmark)

Krivonos, Roman A.; Tomsick, John A.; Bauer, Franz E.

2014-01-01

The Arches cluster is a young, densely packed massive star cluster in our Galaxy that shows a high level of star formation activity. The nature of the extended non-thermal X-ray emission around the cluster remains unclear. The observed bright Fe Ku line emission at 6.4 keV from material that is n......The Arches cluster is a young, densely packed massive star cluster in our Galaxy that shows a high level of star formation activity. The nature of the extended non-thermal X-ray emission around the cluster remains unclear. The observed bright Fe Ku line emission at 6.4 keV from material...... and spectrum. The spatial distribution of the hard X-ray emission is found to be consistent with the broad region around the cluster where the 6.4 keV line is observed. The interpretation of the hard X-ray emission within the context of the X-ray reflection model puts a strong constraint on the luminosity...... of the possible illuminating hard X-ray source. The properties of the observed emission are also in broad agreement with the low-energy cosmic-ray proton excitation scenario....

Hard X-ray Emission and Efficient Particle Acceleration by Supernova Remnants

International Nuclear Information System (INIS)

Vink, Jacco

2009-01-01

I discuss the non-thermal X-ray emission from young supernova remnants. Over the last decade it has become clear from both X-ray and γ-ray observations that young supernovae accelerate particles up to 100 TeV. In soft X-rays the accelerated >10 TeV electrons produce synchrotron radiation, coming from narrow filaments located at the shock fronts. The width of these filaments shows that the magnetic fields are relatively high, thus providing evidence for magnetic field amplification.The synchrotron radiation of several remnants is known to extend into the hard X-ray regime. In particular Cas A, has a spectrum that appears as a power law up to almost 100 TeV. This is very surprising, as a steepening is expected going from the soft to the hard X-ray band. The spectrum is likely a result of many superimposed individual spectra, each steepening at different energies. This implies considerable spatial variation in hard X-rays, an obvious target for Simbol-X. The variations will be important to infer local shock acceleration properties, but also magnetic field fluctuations may cause spatial and temporal variations.Finally, I draw the attention to super bubbles and supernovae as sources of cosmic rays. As such they may be sources of hard X-ray emission. In particular, supernovae exploding inside the dense red supergiants winds of their progenitors ares promising candidates for hard X-ray emission.

Hard X-ray Emission and Efficient Particle Acceleration by Supernova Remnants

Science.gov (United States)

Vink, Jacco

2009-05-01

I discuss the non-thermal X-ray emission from young supernova remnants. Over the last decade it has become clear from both X-ray and γ-ray observations that young supernovae accelerate particles up to 100 TeV. In soft X-rays the accelerated >10 TeV electrons produce synchrotron radiation, coming from narrow filaments located at the shock fronts. The width of these filaments shows that the magnetic fields are relatively high, thus providing evidence for magnetic field amplification. The synchrotron radiation of several remnants is known to extend into the hard X-ray regime. In particular Cas A, has a spectrum that appears as a power law up to almost 100 TeV. This is very surprising, as a steepening is expected going from the soft to the hard X-ray band. The spectrum is likely a result of many superimposed individual spectra, each steepening at different energies. This implies considerable spatial variation in hard X-rays, an obvious target for Simbol-X. The variations will be important to infer local shock acceleration properties, but also magnetic field fluctuations may cause spatial and temporal variations. Finally, I draw the attention to super bubbles and supernovae as sources of cosmic rays. As such they may be sources of hard X-ray emission. In particular, supernovae exploding inside the dense red supergiants winds of their progenitors ares promising candidates for hard X-ray emission.

CORONAL IMPLOSION AND PARTICLE ACCELERATION IN THE WAKE OF A FILAMENT ERUPTION

International Nuclear Information System (INIS)

Liu Rui; Wang Haimin

2009-01-01

We study the evolution of a group of TRACE 195 A coronal loops overlying a reverse S-shaped filament on 2001 June 15. These loops were initially pushed upward with the filament ascending and kinking slowly, but as soon as the filament rose explosively, they began to contract at a speed of ∼100 km s -1 , and sustained for at least 12 minutes, presumably due to the reduced magnetic pressure underneath with the filament escaping. Despite the contraction following the expansion, the loops of interest remained largely intact during the filament eruption, rather than formed via reconnection. These contracting loops naturally formed a shrinking trap, in which hot electrons of several keV, in an order of magnitude estimation, can be accelerated to nonthermal energies. A single hard X-ray (HXR) burst, with no corresponding rise in GOES soft X-ray (SXR) flux, was recorded by the Hard X-ray Telescope (HXT) on board Yohkoh, when the contracting loops expectedly approached the post-flare arcade originating from the filament eruption. HXT images reveal a coronal source distinctly above the top of the SXR arcade by ∼15''. The injecting electron population for the coronal source (thin target) is hardening by ∼1.5 powers relative to the footpoint emission (thick target), which is consistent with electron trapping in the weak diffusion limit. Although we cannot rule out additional reconnection, observational evidence suggests that the shrinking coronal trap may play a significant role in the observed nonthermal HXR emission during the flare decay phase.

Geometry of the non-thermal emission in SN 1006. Azimuthal variations of cosmic-ray acceleration

OpenAIRE

Rothenflug, R.; Ballet, J.; Dubner, Gloria Mabel; Giacani, Elsa Beatriz; Decourchelle, A.; Ferrando, P.

2017-01-01

SN 1006 is the prototype of shell supernova remnants, in which non-thermal synchrotron emission dominates the X-ray spectrum. The non-thermal emission is due to the cosmic-ray electrons accelerated behind the blast wave. The X-ray synchrotron emission is due to the highest energy electrons, and is thus a tracer of the maximum energy electrons may reach behind a shock. We have put together all XMM-Newton observations to build a full map of SN 1006. The very low brightness a...

Nonthermal x-ray emission from a tungsten z-pinch at 5 MA

International Nuclear Information System (INIS)

Sanford, T.W.L.; Nash, T.J.; Marder, B.M.

1995-01-01

The generation of intense bursts of warm x rays with power in the 1-TW regime are of interest for the study of in-depth nuclear radiation effects. Results from high-atomic-number single-wire experiments carried out at 0.8 MA on Gamble II in the 1970s showed 0.25% efficient production of nonthermal, bremsstrahlung-like lines and continuum in the 5- to 100-keV regime. This high efficiency in combination with suggested Z 2 and I 2 scaling of the nonthermal radiation motivated the present experiment to measure and model the radiation from the z pinch formed from compact high-Z wire arrays at high current. In the experiment, tungsten wire arrays of length 20 mm on a mounting radius of 2 mm were imploded over the mass range 1 to 16 mg on the Saturn accelerator operating with a peak discharge current of 5 MA. As in the Gamble-II experiments, bright spots were observed to form at ∼1-mm intervals along the z axis at the time of a first implosion and to be the source of the hard radiation measured. Maximum radiation occurred for masses less than or approximately equal to 4 mg. The experiment was simulated using the LASNEX and TIP numerical codes with a nonthermal model. The timing of the multiple implosions, owing to compression and expansion of the resulting plasma are observed to be in agreement with predictions from both codes and analytic modeling

Amended Results for Hard X-Ray Emission by Non-thermal Thick Target Recombination in Solar Flares

Science.gov (United States)

Reep, J. W.; Brown, J. C.

2016-06-01

Brown & Mallik and the corresponding corrigendum Brown et al. presented expressions for non-thermal recombination (NTR) in the collisionally thin- and thick-target regimes, claiming that the process could account for a substantial part of the hard X-ray continuum in solar flares usually attributed entirely to thermal and non-thermal bremsstrahlung (NTB). However, we have found the thick-target expression to become unphysical for low cut-offs in the injected electron energy spectrum. We trace this to an error in the derivation, derive a corrected version that is real-valued and continuous for all photon energies and cut-offs, and show that, for thick targets, Brown et al. overestimated NTR emission at small photon energies. The regime of small cut-offs and large spectral indices involve large (reducing) correction factors but in some other thick-target parameter regimes NTR/NTB can still be of the order of unity. We comment on the importance of these results to flare and microflare modeling and spectral fitting. An empirical fit to our results shows that the peak NTR contribution comprises over half of the hard X-ray signal if δ ≳ 6{≤ft(\\tfrac{{E}0c}{4{keV}}\\right)}0.4.

THERMAL X-RAY EMISSION FROM THE SHOCKED STELLAR WIND OF PULSAR GAMMA-RAY BINARIES

Energy Technology Data Exchange (ETDEWEB)

Zabalza, V.; Paredes, J. M. [Departament d' Astronomia i Meteorologia, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona (IEEC-UB), Marti i Franques 1, E08028 Barcelona (Spain); Bosch-Ramon, V., E-mail: vzabalza@am.ub.es [Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland)

2011-12-10

Gamma-ray-loud X-ray binaries are binary systems that show non-thermal broadband emission from radio to gamma rays. If the system comprises a massive star and a young non-accreting pulsar, their winds will collide producing broadband non-thermal emission, most likely originated in the shocked pulsar wind. Thermal X-ray emission is expected from the shocked stellar wind, but until now it has neither been detected nor studied in the context of gamma-ray binaries. We present a semi-analytic model of the thermal X-ray emission from the shocked stellar wind in pulsar gamma-ray binaries, and find that the thermal X-ray emission increases monotonically with the pulsar spin-down luminosity, reaching luminosities of the order of 10{sup 33} erg s{sup -1}. The lack of thermal features in the X-ray spectrum of gamma-ray binaries can then be used to constrain the properties of the pulsar and stellar winds. By fitting the observed X-ray spectra of gamma-ray binaries with a source model composed of an absorbed non-thermal power law and the computed thermal X-ray emission, we are able to derive upper limits on the spin-down luminosity of the putative pulsar. We applied this method to LS 5039, the only gamma-ray binary with a radial, powerful wind, and obtain an upper limit on the pulsar spin-down luminosity of {approx}6 Multiplication-Sign 10{sup 36} erg s{sup -1}. Given the energetic constraints from its high-energy gamma-ray emission, a non-thermal to spin-down luminosity ratio very close to unity may be required.

X-ray emission from a high-atomic-number z-pinch plasma created from compact wire arrays

International Nuclear Information System (INIS)

Sanford, T.W.L.; Mosher, D.; De Groot, J.S.

1996-01-01

Thermal and nonthermal x-ray emission from the implosion of compact tungsten wire arrays in 5-MA Saturn discharges is reported. The timing of multiple implosions and the thermal x-ray spectra (1 to 10 keV) agree with 2D radiation-hydrocode simulations. Nonthermal x-ray emission (10 to 100 keV) correlates with pinch spots distributed along the z-axis. The similarities of the measured nonthermal spectrum, yield, and pinch-spot emission with those of 0.8-MA, single-exploded-wire discharges on Gamble-II suggest a common nonthermal-production mechanism. Nonthermal x-ray yields are lower than expected from current scaling of Gamble II results, suggesting that implosion geometries are not as efficient as single-wire geometries for nonthermal x-ray production. The instabilities, azimuthal asymmetries, and inferred multiple implosions that accompany the implosion geometry lead to larger, more irregular pinch spots, a likely reason for reduced nonthermal efficiency. A model for nonthermal-electron acceleration across magnetic fields in highly-collisional, high-atomic-number plasmas combined with 1D hydrocode simulations of Saturn compact loads predicts weak nonthermal x-ray emission. (author). 3 figs., 10 refs

X-ray emission from a high-atomic-number z-pinch plasma created from compact wire arrays

International Nuclear Information System (INIS)

Sanford, T.W.L.; Mosher, D.; De Groot, J.S.

1996-01-01

Thermal and nonthermal x-ray emission from the implosion of compact tungsten wire arrays in 5-MA Saturn discharges is reported. The timing of multiple implosions and the thermal x-ray spectra (1 to 10 keV) agree with 2D radiation-hydrocode simulations. Nonthermal x-ray emission (10 to 100 keV) correlates with pinch spots distributed along the z-axis. The similarities of the measured nonthermal spectrum, yield, and pinch-spot emission with those of 0.8-MA, single- exploded-wire discharges on Gamble-II suggest a common nonthermal- production mechanism. Nonthermal x-ray yields are lower than expected from current scaling of Gamble II results, suggesting that implosion geometries are not as efficient as single-wire geometries for nonthermal x-ray production. The instabilities, azimuthal asymmetries, and inferred multiple implosions that accompany the implosion geometry lead to larger, more irregular pinch spots, a likely reason for reduced nonthermal efficiency. A model for nonthermal-electron acceleration across magnetic fields in highly- collisional, high-atomic-number plasmas combined with 1D hydrocode simulations of Saturn compact loads predicts weak nonthermal x-ray emission

X-Ray Emission Properties of Supernova Remnants

NARCIS (Netherlands)

Vink, J.; Alsabti, A.W.; Murdin, P.

2016-01-01

X-ray emission from supernova remnants can be broadly divided into thermal X-ray emission from the shock-heated plasmas and in nonthermal (synchrotron) emission caused by very high-energy (10–100 TeV) electrons moving in the magnetic fields of the hot plasmas. The thermal X-ray emission of young

Miniature x-ray source

Science.gov (United States)

Trebes, James E.; Bell, Perry M.; Robinson, Ronald B.

2000-01-01

A miniature x-ray source utilizing a hot filament cathode. The source has a millimeter scale size and is capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature source consists of a compact vacuum tube assembly containing the hot filament cathode, an anode, a high voltage feedthru for delivering high voltage to the cathode, a getter for maintaining high vacuum, a connector for initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is fabricated from highly x-ray transparent materials, such as sapphire, diamond, or boron nitride.

A DETAILED STUDY OF NON-THERMAL X-RAY PROPERTIES AND INTERSTELLAR GAS TOWARD THE γ-RAY SUPERNOVA REMNANT RX J1713.7–3946

Energy Technology Data Exchange (ETDEWEB)

Sano, H.; Fukuda, T.; Yoshiike, S.; Sato, J.; Horachi, H.; Kuwahara, T.; Torii, K.; Hayakawa, T.; Matsumoto, H.; Inutsuka, S.; Yamamoto, H.; Tachihara, K. [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Tanaka, T. [Department of Physics, Kyoto University, Kitashirakawa-oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Inoue, T.; Kawamura, A.; Okuda, T.; Mizuno, N. [National Astronomical Observatory of Japan, Mitaka 181-8588 (Japan); Yamazaki, R. [Department of Physics and Mathematics, Aoyama Gakuin University, Fuchinobe, Chuou-ku, Sagamihara 252-5258 (Japan); Onishi, T. [Department of Astrophysics, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531 (Japan); Mizuno, A., E-mail: sano@a.phys.nagoya-u.ac.jp [Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); and others

2015-02-01

We have carried out a spectral analysis of the Suzaku X-ray data in the 0.4-12 keV range toward the shell-type very high-energy γ-ray supernova remnant (SNR) RX J1713.7–3946. The aims of this analysis are to estimate detailed X-rays spectral properties at a high angular resolution up to 2 arcmin and to compare them with the interstellar gas. The X-ray spectrum is non-thermal and used to calculate absorbing column density, photon index, and absorption-corrected X-ray flux. The photon index varies significantly from 2.1 to 2.9. It is shown that the X-ray intensity is well correlated with the photon index, especially in the west region, with a correlation coefficient of 0.81. The X-ray intensity tends to increase with the averaged interstellar gas density while the dispersion is relatively large. The hardest spectra, with photon indexes of less than 2.4, are found outside of the central 10 arcmin of the SNR, from the north to the southeast (∼430 arcmin{sup 2}) and from the southwest to the northwest (∼150 arcmin{sup 2}). The former region shows low interstellar gas density, while the latter shows high interstellar gas density. We present a discussion of possible scenarios that explain the distribution of the photon index and its relationship with the interstellar gas.

A broadband x-ray study of the Geminga pulsar with NuSTAR and XMM-Newton

DEFF Research Database (Denmark)

Mori, Kaya; Gotthelf, Eric V.; Dufour, Francois

2014-01-01

We report on the first hard X-ray detection of the Geminga pulsar above 10 keV using a 150 ks observation with the Nuclear Spectroscopic Telescope Array (NuSTAR) observatory. The double-peaked pulse profile of non-thermal emission seen in the soft X-ray band persists at higher energies. Broadband......V. The spectral hardening in non-thermal X-ray emission as well as spectral flattening between the optical and X-ray bands argue against the conjecture that a single power law may account for multi-wavelength non-thermal spectra of middle-aged pulsars....

X rays from radio binaries

International Nuclear Information System (INIS)

Apparao, K.M.V.

1977-01-01

Reference is made to the radio binary systems CC Cas, AR Lac, β Per (Algol), β Lyr, b Per and Cyg X-1. It is stated that a thermal interpretation of the radiation from Algol requires a much larger x-ray flux than the observed value of 3.8 x 10 -11 erg/cm 2 /sec/keV in the 2 to 6 keV energy range. Observations of some non-thermal flares, together with the small size of the radio source in Algol, indicate that the radio emission is non-thermal in nature. The radio emission is interpreted as synchrotron radiation and it is suggested that the observed x-ray emission is due to inverse Compton scattering of the light of the primary star by the radio electrons. The x-ray emission from other radio binaries is also calculated using this model. The energy for the radio electrons can arise from annihilation of magnetic lines connecting the binary stars, twisted by the rotation of the stars. (U.K.)

X-ray study of bow shocks in runaway stars

Science.gov (United States)

De Becker, M.; del Valle, M. V.; Romero, G. E.; Peri, C. S.; Benaglia, P.

2017-11-01

Massive runaway stars produce bow shocks through the interaction of their winds with the interstellar medium, with the prospect for particle acceleration by the shocks. These objects are consequently candidates for non-thermal emission. Our aim is to investigate the X-ray emission from these sources. We observed with XMM-Newton a sample of five bow shock runaways, which constitutes a significant improvement of the sample of bow shock runaways studied in X-rays so far. A careful analysis of the data did not reveal any X-ray emission related to the bow shocks. However, X-ray emission from the stars is detected, in agreement with the expected thermal emission from stellar winds. On the basis of background measurements we derive conservative upper limits between 0.3 and 10 keV on the bow shocks emission. Using a simple radiation model, these limits together with radio upper limits allow us to constrain some of the main physical quantities involved in the non-thermal emission processes, such as the magnetic field strength and the amount of incident infrared photons. The reasons likely responsible for the non-detection of non-thermal radiation are discussed. Finally, using energy budget arguments, we investigate the detectability of inverse Compton X-rays in a more extended sample of catalogued runaway star bow shocks. From our analysis we conclude that a clear identification of non-thermal X-rays from massive runaway bow shocks requires one order of magnitude (or higher) sensitivity improvement with respect to present observatories.

Hard X-ray Emission from Galaxy Clusters Observed with INTEGRAL and Prospects for Simbol-X

Science.gov (United States)

Eckert, D.; Paltani, S.; Courvoisier, T. J.-L.

2009-05-01

Some galaxy clusters are known to contain a large population of relativistic electrons, which produce radio emission through synchrotron radiation. Therefore, it is expected that inverse-Compton scattering of the relativistic electrons with the CMB produce non-thermal emission which should be observable in the hard X-ray domain. Here we focus on the recent results by INTEGRAL, which shed a new light on the non-thermal emission thanks to its angular resolution and sensitivity in the hard X-ray range. We also present the exciting prospects in this field for Simbol-X, which will allow us to detect the non-thermal emission in a number of clusters and map the magnetic field throughout the intra-cluster medium.

Non-thermal emission from young supernova remnants: Implications on cosmic ray acceleration

Science.gov (United States)

Araya-Arguedas, Miguel A.

For a long time, supernova remnants have been thought to constitute the main source of galactic cosmic rays. Plausible mechanisms have been proposed through which these objects would be able to transfer some of their energy to charged particles. Detailed studies of SNRs, particularly allowed by the spectral and spatial resolution obtained with telescopes such as the Chandra X-Ray Observatory , have permitted us to understand some of the properties of high-energy particles within these objects and their interactions with their environment. In the first part of this work, the basic concepts of particle acceleration in SNRs are outlined, and the main observational tools available today for studying high-energy phenomena in astrophysics are mentioned briefly. In the second part, a study of non-thermal emission from the young SNR Cassiopeia A is presented. Through the use of a very deep one million-second Chandra observation of this remnant, the spectral evolution across non-thermal filaments near the forward shock was studied. A consistent hardening of the spectrum towards the exterior of the remnant was found and explained via a model developed that takes into account particle diffusion, plasma advection and radiation losses. The role of particle diffusion was studied and its effect on the photon spectral index quantified. In the model, the diffusion is included as a fraction of Bohm-type diffusion, which is consistent with the data. The model also allowed an estimation of the electron distribution, the magnetic field and its orientation, as well as the level of magnetic turbulence. In the third part, a multi-wavelength study of two young SNRs is presented. Multi-wavelength modeling of spectral energy distributions (SED) may hold the key to disentangle the nature and content of cosmic rays within these objects. The first model shown presents state of the art measurements gathered for Cassiopeia A, and the modeling is based partly on the results presented in the second

X-Ray and Near-Infrared Spectroscopy of Dim X-Ray Point Sources Constituting the Galactic Ridge X-Ray Emission

Directory of Open Access Journals (Sweden)

Kumiko Morihana

2014-12-01

Full Text Available We present the results of X-ray and Near-Infrared observations of the Galactic Ridge X-ray Emission (GRXE. We extracted 2,002 X-ray point sources in the Chandra Bulge Field (l =0°.113, b = 1°.424 down to ~10-14.8 ergscm-2s-1 in 2-8 keV band with the longest observation (900 ks of the GRXE. Based on X-ray brightness and hardness, we classied the X-ray point sources into three groups: A (hard, B (soft and broad spectrum, and C (soft and peaked spectrum. In order to know populations of the X-ray point sources, we carried out NIR imaging and spectroscopy observation. We identied 11% of X-ray point sources with NIR and extracted NIR spectra for some of them. Based on X-ray and NIR properties, we concluded that non-thermal sources in the group A are mostly active galactic nuclei and the thermal sources are mostly white dwarf binaries such as cataclysmic variables (CVs and Pre-CVs. We concluded that the group B and C sources are X-ray active stars in flare and quiescence, respectively.

Detection of non-thermal X-ray emission in the lobes and jets of Cygnus A

Science.gov (United States)

de Vries, M. N.; Wise, M. W.; Huppenkothen, D.; Nulsen, P. E. J.; Snios, B.; Hardcastle, M. J.; Birkinshaw, M.; Worrall, D. M.; Duffy, R. T.; McNamara, B. R.

2018-06-01

We present a spectral analysis of the lobes and X-ray jets of Cygnus A, using more than 2 Ms of Chandra observations. The X-ray jets are misaligned with the radio jets and significantly wider. We detect non-thermal emission components in both lobes and jets. For the eastern lobe and jet, we find 1 keV flux densities of 71_{-10}^{+10} nJy and 24_{-4}^{+4} nJy, and photon indices of 1.72_{-0.03}^{+0.03} and 1.64_{-0.04}^{+0.04} respectively. For the western lobe and jet, we find flux densities of 50_{-13}^{+12} nJy and 13_{-5}^{+5} nJy, and photon indices of 1.97_{-0.10}^{+0.23} and 1.86_{-0.12}^{+0.18} respectively. Using these results, we modeled the electron energy distributions of the lobes as broken power laws with age breaks. We find that a significant population of non-radiating particles is required to account for the total pressure of the eastern lobe. In the western lobe, no such population is required and the low energy cutoff to the electron distribution there needs to be raised to obtain pressures consistent with observations. This discrepancy is a consequence of the differing X-ray photon indices, which may indicate that the turnover in the inverse-Compton spectrum of the western lobe is at lower energies than in the eastern lobe. We modeled the emission from both jets as inverse-Compton emission. There is a narrow region of parameter space for which the X-ray jet can be a relic of an earlier active phase, although lack of knowledge about the jet's electron distribution and particle content makes the modelling uncertain.

Signatures of Synchrotron: Low-cutoff X-ray emission and the hard X-ray spectrum of Cas A

Science.gov (United States)

Stage, Michael D.; Fedor, Emily Elizabeth; Martina-Hood, Hyourin

2018-06-01

In soft X-rays, bright, young Galactic remnants (Cas A, Kepler, Tycho, etc.) present thermal line emission and bremsstrahlung from ejecta, and synchrotron radiation from the shocks. Their hard X-ray spectra tend to be dominated by power-law sources. However, it can be non-trivial to discriminate between contributions from processes such as synchrotron and bremsstrahlung from nonthermally accelerated electrons, even though the energies of the electrons producing this radiation may be very different. Spatially-resolved spectroscopic analysis of 0.5-10 keV observations with, e.g., Chandracan provide leverage in identifying the processes and their locations. Previously, Stage & Allen (2006), Allen & Stage (2007) and Stage & Allen (2011) identified regions characterized by high-cutoff synchrotron radiation. Extrapolating synchrotron model fits to the emission in the Chandra band, they estimated the synchrotron contribution to the hard X-ray spectrum at about one-third the observed flux, fitting the balance with nonthermal bremsstrahlung emission produced by nonthermal electrons in the ejecta. Although it is unlikely this analysis missed regions of the highest-cutoff synchrotron emission, which supplies the bulk of the synchrotron above 15 keV, it may have missed regions of lower-cutoff emission, especially if they are near bright ejecta and the reverse shock. These regions cannot explain the emission at the highest energies (~50 keV), but may make significant contributions to the hard spectrum at lower energies (~10 keV). Using the technique described in Fedor, Martina-Hood & Stage (this meeting), we revisit the analysis to include regions that may be dominated by low-cutoff synchrotron, located in the interior of the remnant, and/or correlated with the reverse shock. Identifying X-ray emission from accelerated electrons associated with the reverse-shock would have important implications for synchrotron and non-thermal bremsstrahlung radiation above the 10 keV.

X-ray fluorescence (XRF) set-up with a low power X-ray tube

International Nuclear Information System (INIS)

Gupta, Sheenu; Deep, Kanan; Jain, Lalita; Ansari, M.A.; Mittal, Vijay Kumar; Mittal, Raj

2010-01-01

The X-ray fluorescence set-up with a 100 W X-ray tube comprises a computer controlled system developed for remote operation and monitoring of tube and an adjustable stable 3D arrangement to procure variable excitation energies with low scattered background. The system was tested at different filament currents/anode voltages. The MDL of the set-up at 0.05-1.00 mA/4-12 kV is found ∼(1-100) ppm for K and L excitations and ∼(200-700) ppm for M excitations of elements and improves with filament current and anode voltage. Moreover, L measurements for Sm and Eu at five K X-ray energies of elements(Z=29-40) and analytical determination in some synthetic samples were undertaken.

X-ray emission from a high-atomic-number z-pinch plasma created from compact wire arrays

International Nuclear Information System (INIS)

Sanford, T.W.L.; Nash, T.J.; Marder, B.M.

1996-03-01

Thermal and nonthermal x-ray emission from the implosion of compact tungsten wire arrays, driven by 5 MA from the Saturn accelerator, are measured and compared with LLNL Radiation-Hydro-Code (RHC) and SNL Hydro-Code (HC) numerical models. Multiple implosions, due to sequential compressions and expansions of the plasma, are inferred from the measured multiple x-radiation bursts. Timing of the multiple implosions and the thermal x-ray spectra measured between 1 and 10 keV are consistent with the RHC simulations. The magnitude of the nonthermal x-ray emission measured from 10 to 100 keV ranges from 0.02 to 0.08% of the total energy radiated and is correlated with bright-spot emission along the z-axis, as observed in earlier Gamble-11 single exploding-wire experiments. The similarities of the measured nonthermal spectrum and bright-spot emission with those measured at 0.8 MA on Gamble-II suggest a common production mechanism for this process. A model of electron acceleration across magnetic fields in highly-collisional, high-atomic-number plasmas is developed, which shows the existence of a critical electric field, E c , below which strong nonthermal electron creation (and the associated nonthermal x rays) do not occur. HC simulations show that significant nonthermal electrons are not expected in this experiment (as observed) because the calculated electric fields are at least one to two orders-of-magnitude below E c . These negative nonthermal results are confirmed by RHC simulations using a nonthermal model based on a Fokker-Plank analysis. Lastly, the lower production efficiency and the larger, more irregular pinch spots formed in this experiment relative to those measured on Gamble II suggest that implosion geometries are not as efficient as single exploding-wire geometries for warm x-ray production

PARTICLE ACCELERATION AND THE ORIGIN OF X-RAY FLARES IN GRMHD SIMULATIONS OF SGR A*

Energy Technology Data Exchange (ETDEWEB)

Ball, David; Özel, Feryal; Psaltis, Dimitrios; Chan, Chi-kwan [Steward Observatory and Department of Astronomy, University of Arizona (United States)

2016-07-20

Significant X-ray variability and flaring has been observed from Sgr A* but is poorly understood from a theoretical standpoint. We perform general relativistic magnetohydrodynamic simulations that take into account a population of non-thermal electrons with energy distributions and injection rates that are motivated by PIC simulations of magnetic reconnection. We explore the effects of including these non-thermal electrons on the predicted broadband variability of Sgr A* and find that X-ray variability is a generic result of localizing non-thermal electrons to highly magnetized regions, where particles are likely to be accelerated via magnetic reconnection. The proximity of these high-field regions to the event horizon forms a natural connection between IR and X-ray variability and accounts for the rapid timescales associated with the X-ray flares. The qualitative nature of this variability is consistent with observations, producing X-ray flares that are always coincident with IR flares, but not vice versa, i.e., there are a number of IR flares without X-ray counterparts.

X-RAY STUDIES OF THE BLACK WIDOW PULSAR PSR B1957+20

International Nuclear Information System (INIS)

Huang, R. H. H.; Kong, A. K. H.; Takata, J.; Cheng, K. S.; Hui, C. Y.; Lin, L. C. C.

2012-01-01

We report on Chandra observations of the black widow pulsar, PSR B1957+20. Evidence for a binary-phase dependence of the X-ray emission from the pulsar is found with a deep observation. The binary-phase-resolved spectral analysis reveals non-thermal X-ray emission of PSR B1957+20, confirming the results of previous studies. This suggests that the X-rays are mostly due to intra-binary shock emission, which is strongest when the pulsar wind interacts with the ablated material from the companion star. The geometry of the peak emission is determined in our study. The marginal softening of the spectrum of the non-thermal X-ray tail may indicate that particles injected at the termination shock are dominated by synchrotron cooling.

A Nonthermal Radio Filament Connected to the Galactic Black Hole?

Science.gov (United States)

Morris, Mark R.; Zhao, Jun-Hui; Goss, W. M.

2017-12-01

Using the Very Large Array, we have investigated a nonthermal radio filament (NTF) recently found very near the Galactic black hole and its radio counterpart, Sgr A*. While this NTF—the Sgr A West Filament (SgrAWF)—shares many characteristics with the population of NTFs occupying the central few hundred parsecs of the Galaxy, the SgrAWF has the distinction of having an orientation and sky location that suggest an intimate physical connection to Sgr A*. We present 3.3 and 5.5 cm images constructed using an innovative methodology that yields a very high dynamic range, providing an unprecedentedly clear picture of the SgrAWF. While the physical association of the SgrAWF with Sgr A* is not unambiguous, the images decidedly evoke this interesting possibility. Assuming that the SgrAWF bears a physical relationship to Sgr A*, we examine the potential implications. One is that Sgr A* is a source of relativistic particles constrained to diffuse along ordered local field lines. The relativistic particles could also be fed into the local field by a collimated outflow from Sgr A*, perhaps driven by the Poynting flux accompanying the black hole spin in the presence of a magnetic field threading the event horizon. Second, we consider the possibility that the SgrAWF is the manifestation of a low-mass-density cosmic string that has become anchored to the black hole. The simplest form of these hypotheses would predict that the filament be bi-directional, whereas the SgrAWF is only seen on one side of Sgr A*, perhaps because of the dynamics of the local medium.

Polarization of hard X-rays, a contribution to the measurement of the non-thermal electron distribution function (L.H.C.D.)

International Nuclear Information System (INIS)

Hesse, M.; Platz, P.

1990-01-01

The hard X-ray spectrum emitted by a plasma containing non-thermal electrons generated during Lower Hybrid Current Drive experiments has already been measured on several tokamaks, but the properties of the bremsstrahlung have not yet been studied. The present study starts with the comparison of tractable analytical expressions of cross-sections with more precise computer-calculated values; then an evaluation of the polarization is carried out under real tokamak current drive situations and finally a proposal of a new diagnostic for the Tore Supra LHCD experiment is presented. (author) 6 refs., 6 figs

Gamma rays from Cygnus X-1: Modeling and nonthermal pair production

International Nuclear Information System (INIS)

Dermer, C.D.; Liang, E.P.

1988-02-01

The gamma-ray bump observed between 0.5 and 2 MeV in the spectrum of Cygnus X-1 can be interpreted as the thermal emissions from a hot (kT/approximately/400 keV) pair-dominated cloud. We argue that the X-rays and gamma rays are produced in separate emission regions, and calculate the photon-photon pair production rate from X-ray and gamma-ray interactions in the vicinity of Cyg X-1 by employing a simplified geometry for the two emitting regions

Nonthermal and screening effects on photoionizations in Lorentzian plasmas

International Nuclear Information System (INIS)

Shin, Dong-Soo; Jung, Young-Dae

2009-01-01

The nonthermal and plasma screening effects on the x-ray photoionization process are investigated in astrophysical Lorentzian plasmas. The screened atomic wave function and energy eigenvalue of the target ion in Lorentzian plasmas are obtained by the Rayleigh-Ritz variational method. The x-ray retardation and screened Coulomb corrections are considered to obtain a photoionization cross section as a function of the spectral index and plasma parameters. It is shown that the nonthermal character of the Lorentzian plasma suppresses the photoionization cross section. Hence, the photoionization cross sections in nonthermal plasmas are found to be always smaller than those in thermal plasmas. It is also shown that the plasma screening effect is more significant for small spectral indices. In addition, the nonthermal effect on the photoionization cross section is found to be decreased with an increase in the Debye length.

Soft x-ray induced femtosecond solid-to-solid phase transition

Czech Academy of Sciences Publication Activity Database

Tavella, F.; Höppner, H.; Tkachenko, V.; Medvedev, Nikita; Capotondi, F.; Golz, T.; Kai, Y.; Manfredda, M.; Pedersoli, E.; Prandolini, M.J.; Stojanovic, N.; Tanikawa, T.; Teubner, U.; Toleikis, S.; Ziaja, B.

Roč. 24, Sep (2017), s. 22-27 ISSN 1574-1818 Institutional support: RVO:68378271 Keywords : soft x-ray * ultrashort x-ray pulses * grafitization of diamond * non-thermal phase transition Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 0.908, year: 2016

A giant radio flare from Cygnus X-3 with associated γ-ray emission: The 2011 radio and γ-ray flare of Cyg X-3

International Nuclear Information System (INIS)

Corbel, S.; Dubus, G.; Tomsick, J. A.; Szostek, A.

2012-01-01

With frequent flaring activity of its relativistic jets, Cygnus X-3 (Cyg X-3) is one of the most active microquasars and is the only Galactic black hole candidate with confirmed high-energy γ-ray emission, thanks to detections by Fermi Large Area Telescope (Fermi/LAT) and AGILE. In 2011, we observed Cyg X-3 in order to transit to a soft X-ray state, which is known to be associated with high-energy γ-ray emission. We present the results of a multiwavelength campaign covering a quenched state, when radio emission from Cyg X-3 is at its weakest and the X-ray spectrum is very soft. A giant (~20 Jy) optically thin radio flare marks the end of the quenched state, accompanied by rising non-thermal hard X-rays. Fermi/LAT observations (E≥ 100 MeV) reveal renewed γ-ray activity associated with this giant radio flare, suggesting a common origin for all non-thermal components. In addition, current observations unambiguously show that the γ-ray emission is not exclusively related to the rare giant radio flares. A three-week period of γ-ray emission is also detected when Cyg X-3 was weakly flaring in radio, right before transition to the radio quenched state. There were no γ-rays observed during the ~1-month long quenched state, when the radio flux is weakest. These results suggest transitions into and out of the ultrasoft X-ray (radio-quenched) state trigger γ-ray emission, implying a connection to the accretion process, and also that the γ-ray activity is related to the level of radio flux (and possibly shock formation), strengthening the connection to the relativistic jets.

A Spatial Study of X-ray Properties in Superbubble 30 Dor C with XMM-Newton

Science.gov (United States)

Babazaki, Yasunori; Mitsuishi, Ikuyuki; SANO, Hidetoshi; Yoshiike, Satoshi; Fukuda, Tatsuya; Maruyama, Shohei; Fujii, Kosuke; Fukui, Yasuo; Tawara, Yuzuru; Matsumoto, Hironori

2015-08-01

Supernova remnants (SNRs) in the Galaxy are believed to be most likely accelerators of cosmic-rays (CRs) in an energy range less than 3×10^15 eV. Thus SNRs emit synchrotron X-rays by high-energy electrons. Sano et al. (2014) investigated spatially-resolved X-ray spectral properties of a shell-type SNR RX1713.77-3946 which shows strong non-thermal X-ray emissions. A large variation in the photon index is found and the photon index tends to be hard with increasing an interstellar gas density, suggesting that CR electrons are efficiently accelerated in denser interstellar gas environments. Few studies have focused on a photon index variation in superbubbles which possess 100-1000 pc diameter shells of swept-up interstellar materials containing hot (~10^6 K) shock-heated gas. The superbubble 30 Dor C in the Large Magellanic Cloud is one of the best targets for examining the photon index variation, because 30 Dor C is by far strong non-thermal X-ray emissions, and thus provides an ideal laboratory for probing non-thermal emission mechanisms in the supperbubble. We investigated X-ray spectral properties of the superbubble with a high spatial resolution of on the order of 10 pc. Consequently, the spectra in the west region of 30 Dor C can be described with a combination of absorbed thermal and non-thermal models while the spectra in the east region can be fitted with an absorbed non-thermal model. The photon index and intensity in 2-10 keV show variations of 2.0-3.5 and (0.6-8.0) × 10^-7 erg/s/cm^2, respectively. The temperature of the thermal component ranges from ~0.1 to ~0.3 keV. We will discuss an interaction between the hot gas and an interstellar gas using mutiwavelength data.

Radio Videos of Orion Protostars (with X-ray Colors!)

Science.gov (United States)

Forbrich, Jan; Wolk, Scott; Menten, Karl; Reid, Mark; Osten, Rachel

2013-07-01

High-energy processes in Young Stellar Objects (YSOs) can be observed both in X-rays and in the centimetric radio wavelength range. While the past decade has brought a lot of progress in the field of X-ray observations of YSOs, (proto)stellar centimetric radio astronomy has only recently begun to catch up with the advent of the newly expanded Karl G. Jansky Very Large Array (JVLA). The enhanced sensitivity is fundamentally improving our understanding of YSO radio properties by providing unprecedented sensitivity and thus spectral as well as temporal resolution. As a result, it is becoming easier to disentangle coronal-type nonthermal radio emission emanating from the immediate vicinity of YSOs from thermal emission on larger spatial scales, for example ionized material at the base of outflows. Of particular interest is the correlation of the by now relatively well-characterized X-ray flaring variability with the nonthermal radio variability. We present first results of multi-epoch simultaneous observations using Chandra and the JVLA, targeting the Orion Nebula Cluster and highlighting the capabilities of the JVLA for radio continuum observations of YSOs.

Topics in Astrophysical X-Ray and Gamma Ray Spectroscopy. Ph.D. Thesis - Maryland Univ.

Science.gov (United States)

Bussard, R. W.

1978-01-01

A number of topics relating to astrophysical observations that have already been made or are currently planned of spectral features, mostly emission lines, in the X-ray and gamma ray region of the electromagnetic spectrum are investigated. These topics include: the production of characteristic X-ray and gamma ray lines by nonthermal ions, spectral features induced by processes occurring in strong magnetic fields, and the positron annihilation line at 0.5 MeV. The rate of X-ray production at 6.8 keV by the 2p to 1s transition in fast hydrogen- and helium-like iron ions, following both electron capture to excited levels and collisional excitation is calculated. The cross section for electron-ion Coulomb collisions in strong fields is also calculated.

Hard X-Ray Emission from Partially Occulted Solar Flares: RHESSI Observations in Two Solar Cycles

Energy Technology Data Exchange (ETDEWEB)

Effenberger, Frederic; Costa, Fatima Rubio da; Petrosian, Vahé [Department of Physics and KIPAC, Stanford University, Stanford, CA 94305 (United States); Oka, Mitsuo; Saint-Hilaire, Pascal; Krucker, Säm [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States); Liu, Wei [Bay Area Environmental Research Institute, 625 2nd Street, Suite 209, Petaluma, CA 94952 (United States); Glesener, Lindsay, E-mail: feffen@stanford.edu, E-mail: frubio@stanford.edu [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2017-02-01

Flares close to the solar limb, where the footpoints are occulted, can reveal the spectrum and structure of the coronal looptop source in X-rays. We aim at studying the properties of the corresponding energetic electrons near their acceleration site, without footpoint contamination. To this end, a statistical study of partially occulted flares observed with Reuven Ramaty High-Energy Solar Spectroscopic Imager is presented here, covering a large part of solar cycles 23 and 24. We perform detailed spectra, imaging, and light curve analyses for 116 flares and include contextual observations from SDO and STEREO when available, providing further insights into flare emission that were previously not accessible. We find that most spectra are fitted well with a thermal component plus a broken power-law, non-thermal component. A thin-target kappa distribution model gives satisfactory fits after the addition of a thermal component. X-ray imaging reveals small spatial separation between the thermal and non-thermal components, except for a few flares with a richer coronal source structure. A comprehensive light curve analysis shows a very good correlation between the derivative of the soft X-ray flux (from GOES ) and the hard X-rays for a substantial number of flares, indicative of the Neupert effect. The results confirm that non-thermal particles are accelerated in the corona and estimated timescales support the validity of a thin-target scenario with similar magnitudes of thermal and non-thermal energy fluxes.

Synchronous x-ray and radio mode switches: a rapid global transformation of the pulsar magnetosphere.

Science.gov (United States)

Hermsen, W; Hessels, J W T; Kuiper, L; van Leeuwen, J; Mitra, D; de Plaa, J; Rankin, J M; Stappers, B W; Wright, G A E; Basu, R; Alexov, A; Coenen, T; Grießmeier, J-M; Hassall, T E; Karastergiou, A; Keane, E; Kondratiev, V I; Kramer, M; Kuniyoshi, M; Noutsos, A; Serylak, M; Pilia, M; Sobey, C; Weltevrede, P; Zagkouris, K; Asgekar, A; Avruch, I M; Batejat, F; Bell, M E; Bell, M R; Bentum, M J; Bernardi, G; Best, P; Bîrzan, L; Bonafede, A; Breitling, F; Broderick, J; Brüggen, M; Butcher, H R; Ciardi, B; Duscha, S; Eislöffel, J; Falcke, H; Fender, R; Ferrari, C; Frieswijk, W; Garrett, M A; de Gasperin, F; de Geus, E; Gunst, A W; Heald, G; Hoeft, M; Horneffer, A; Iacobelli, M; Kuper, G; Maat, P; Macario, G; Markoff, S; McKean, J P; Mevius, M; Miller-Jones, J C A; Morganti, R; Munk, H; Orrú, E; Paas, H; Pandey-Pommier, M; Pandey, V N; Pizzo, R; Polatidis, A G; Rawlings, S; Reich, W; Röttgering, H; Scaife, A M M; Schoenmakers, A; Shulevski, A; Sluman, J; Steinmetz, M; Tagger, M; Tang, Y; Tasse, C; ter Veen, S; Vermeulen, R; van de Brink, R H; van Weeren, R J; Wijers, R A M J; Wise, M W; Wucknitz, O; Yatawatta, S; Zarka, P

2013-01-25

Pulsars emit from low-frequency radio waves up to high-energy gamma-rays, generated anywhere from the stellar surface out to the edge of the magnetosphere. Detecting correlated mode changes across the electromagnetic spectrum is therefore key to understanding the physical relationship among the emission sites. Through simultaneous observations, we detected synchronous switching in the radio and x-ray emission properties of PSR B0943+10. When the pulsar is in a sustained radio-"bright" mode, the x-rays show only an unpulsed, nonthermal component. Conversely, when the pulsar is in a radio-"quiet" mode, the x-ray luminosity more than doubles and a 100% pulsed thermal component is observed along with the nonthermal component. This indicates rapid, global changes to the conditions in the magnetosphere, which challenge all proposed pulsar emission theories.

Non-thermal AGN models

Energy Technology Data Exchange (ETDEWEB)

Band, D.L.

1986-12-01

The infrared, optical and x-ray continua from radio quiet active galactic nuclei (AGN) are explained by a compact non-thermal source surrounding a thermal ultraviolet emitter, presumably the accretion disk around a supermassive black hole. The ultraviolet source is observed as the ''big blue bump.'' The flat (..cap alpha.. approx. = .7) hard x-ray spectrum results from the scattering of thermal ultraviolet photons by the flat, low energy end of an electron distribution ''broken'' by Compton losses; the infrared through soft x-ray continuum is the synchrotron radiation of the steep, high energy end of the electron distribution. Quantitative fits to specific AGN result in models which satisfy the variability constraints but require electron (re)acceleration throughout the source. 11 refs., 1 fig.

X- and γ-ray pulsations of the nearby radio-faint PSR J1741–2054

Energy Technology Data Exchange (ETDEWEB)

Marelli, M.; Belfiore, A.; Caraveo, P.; De Luca, A.; Salvetti, D. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via E. Bassini 15, I-20133 Milano (Italy); Saz Parkinson, P. [Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064 (United States); Sarazin, C.; Sivakoff, G. R. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Camilo, F., E-mail: marelli@lambrate.inaf.it [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States)

2014-07-20

We report the results of a deep XMM-Newton observation of the radio-faint γ-ray pulsar J1741–2054 and its nebula together with the analysis of five years of Fermi Large Area Telescope (LAT) data. The X-ray spectrum of the pulsar is consistent with an absorbed power law plus a blackbody, originating at least partly from the neutron star cooling. The nebular emission is consistent with that of a synchrotron pulsar wind nebula, with hints of spatial spectral variation. We extended the available Fermi LAT ephemeris and folded the γ-ray and X-ray data. We detected X-ray pulsations from the neutron star: both the thermal and non-thermal components are ∼35%-40% pulsed, with phase-aligned maxima. A sinusoid fits the thermal-folded profile well. A 10 bin phase-resolved analysis of the X-ray emission shows softening of the non-thermal spectrum during the on-pulse phases. The radio, X-ray, and γ-ray light curves are single-peaked, not phase-aligned, with the X-ray peak trailing the γ-ray peak by more than half a rotation. Spectral considerations suggest that the most probable pulsar distance is in the 0.3-1.0 kpc range, in agreement with the radio dispersion measure.

X- and γ-ray pulsations of the nearby radio-faint PSR J1741–2054

International Nuclear Information System (INIS)

Marelli, M.; Belfiore, A.; Caraveo, P.; De Luca, A.; Salvetti, D.; Saz Parkinson, P.; Sarazin, C.; Sivakoff, G. R.; Camilo, F.

2014-01-01

We report the results of a deep XMM-Newton observation of the radio-faint γ-ray pulsar J1741–2054 and its nebula together with the analysis of five years of Fermi Large Area Telescope (LAT) data. The X-ray spectrum of the pulsar is consistent with an absorbed power law plus a blackbody, originating at least partly from the neutron star cooling. The nebular emission is consistent with that of a synchrotron pulsar wind nebula, with hints of spatial spectral variation. We extended the available Fermi LAT ephemeris and folded the γ-ray and X-ray data. We detected X-ray pulsations from the neutron star: both the thermal and non-thermal components are ∼35%-40% pulsed, with phase-aligned maxima. A sinusoid fits the thermal-folded profile well. A 10 bin phase-resolved analysis of the X-ray emission shows softening of the non-thermal spectrum during the on-pulse phases. The radio, X-ray, and γ-ray light curves are single-peaked, not phase-aligned, with the X-ray peak trailing the γ-ray peak by more than half a rotation. Spectral considerations suggest that the most probable pulsar distance is in the 0.3-1.0 kpc range, in agreement with the radio dispersion measure.

A broadband X-ray study of the Geminga pulsar with NuSTAR And XMM-Newton

International Nuclear Information System (INIS)

Mori, Kaya; Gotthelf, Eric V.; Halpern, Jules P.; Beloborodov, Andrei M.; Hailey, Charles J.; Dufour, Francois; Kaspi, Victoria M.; An, Hongjun; Bachetti, Matteo; Boggs, Steven E.; Craig, William W.; Christensen, Finn E.; Harrison, Fiona A.; Kouveliotou, Chryssa; Pivovaroff, Michael J.; Stern, Daniel; Zhang, William W.

2014-01-01

We report on the first hard X-ray detection of the Geminga pulsar above 10 keV using a 150 ks observation with the Nuclear Spectroscopic Telescope Array (NuSTAR) observatory. The double-peaked pulse profile of non-thermal emission seen in the soft X-ray band persists at higher energies. Broadband phase-integrated spectra over the 0.2-20 keV band with NuSTAR and archival XMM-Newton data do not fit to a conventional two-component model of a blackbody plus power law, but instead exhibit spectral hardening above ∼5 keV. We find that two spectral models fit the data well: (1) a blackbody (kT 1 ∼ 42 eV) with a broken power law (Γ 1 ∼ 2.0, Γ 2 ∼ 1.4 and E break ∼ 3.4 keV) and (2) two blackbody components (kT 1 ∼ 44 eV and kT 2 ∼ 195 eV) with a power-law component (Γ ∼ 1.7). In both cases, the extrapolation of the Rayleigh-Jeans tail of the thermal component is consistent with the UV data, while the non-thermal component overpredicts the near-infrared data, requiring a spectral flattening at E ∼ 0.05-0.5 keV. While strong phase variation of the power-law index is present below ∼5 keV, our phase-resolved spectroscopy with NuSTAR indicates that another hard non-thermal component with Γ ∼ 1.3 emerges above ∼5 keV. The spectral hardening in non-thermal X-ray emission as well as spectral flattening between the optical and X-ray bands argue against the conjecture that a single power law may account for multi-wavelength non-thermal spectra of middle-aged pulsars.

UV and X-ray Evolution of AR12230 as Observed with IRIS and FOXSI-II

Science.gov (United States)

Ryan, Daniel; Christe, Steven; Glesener, Lindsay; Vievering, Julie; Krucker, Sam; Ishikawa, Shin-Nosuke

2017-08-01

We present a multi-spectral and spatio-temporal analysis of AR12230 using both UV and X-ray spectroscopic imaging obtained as part of a coordinated observing campaign on 11 December 2014. The campaign involved IRIS (Interface Region Imaging Spectrometer) -- which provides both UV imaging and slit spectrograph observations of optically thick chromospheric and transition region emission -- and FOXSI-II (Focusing Optics X-ray Solar Imager) -- the second in a series of sounding rocket flights which combines grazing incidence direct focusing optics to produce solar X-ray spectroscopic imaging in the range 4-15keV. The active region exhibits a prolonged compact brightening in the IRIS 1330 A and 1400 A slit-jaw channels near the center of the active region throughout the duration of the observations. In the early phase of the observations FOXSI-II shows an X-ray source approximately 20x20 arcsec centered at the same location. The X-ray spectra show the presence of hot (~8 MK) thermal plasma and is suggestive of the presence of non-thermal electrons.. Later, two additional transient, spatially extended, simultaneous brightenings are observed, one of which was captured by the IRIS slit spectrograph. We combine these observations to explore the evolution and topology of the active region. Hydrodynamic modeling of the chromosphere is used to place a limit on the amount of non-thermal electrons required to produce the observed UV emission. This result is then compared to the limit inferred from the FOXSI-II X-ray spectra. Thus, we explore the role of non-thermal electrons and hydrodynamics in the energization and evolution of plasma in active regions.

A giant radio flare from Cygnus X-3 with associated γ-ray emission

Science.gov (United States)

Corbel, S.; Dubus, G.; Tomsick, J. A.; Szostek, A.; Corbet, R. H. D.; Miller-Jones, J. C. A.; Richards, J. L.; Pooley, G.; Trushkin, S.; Dubois, R.; Hill, A. B.; Kerr, M.; Max-Moerbeck, W.; Readhead, A. C. S.; Bodaghee, A.; Tudose, V.; Parent, D.; Wilms, J.; Pottschmidt, K.

2012-04-01

With frequent flaring activity of its relativistic jets, Cygnus X-3 (Cyg X-3) is one of the most active microquasars and is the only Galactic black hole candidate with confirmed high-energy γ-ray emission, thanks to detections by Fermi Large Area Telescope (Fermi/LAT) and AGILE. In 2011, Cyg X-3 was observed to transit to a soft X-ray state, which is known to be associated with high-energy γ-ray emission. We present the results of a multiwavelength campaign covering a quenched state, when radio emission from Cyg X-3 is at its weakest and the X-ray spectrum is very soft. A giant (˜20 Jy) optically thin radio flare marks the end of the quenched state, accompanied by rising non-thermal hard X-rays. Fermi/LAT observations (E≥ 100 MeV) reveal renewed γ-ray activity associated with this giant radio flare, suggesting a common origin for all non-thermal components. In addition, current observations unambiguously show that the γ-ray emission is not exclusively related to the rare giant radio flares. A three-week period of γ-ray emission is also detected when Cyg X-3 was weakly flaring in radio, right before transition to the radio quenched state. No γ-rays are observed during the ˜1-month long quenched state, when the radio flux is weakest. Our results suggest transitions into and out of the ultrasoft X-ray (radio-quenched) state trigger γ-ray emission, implying a connection to the accretion process, and also that the γ-ray activity is related to the level of radio flux (and possibly shock formation), strengthening the connection to the relativistic jets.

X-Ray Source Heights in a Solar Flare: Thick-Target Versus Thermal Conduction Front Heating

Science.gov (United States)

Reep, J. W.; Bradshaw, S. J.; Holman, G. D.

2016-01-01

Observations of solar flares with RHESSI have shown X-ray sources traveling along flaring loops, from the corona down to the chromosphere and back up. The 2002 November 28 C1.1 flare, first observed with RHESSI by Sui et al. and quantitatively analyzed by O'Flannagain et al., very clearly shows this behavior. By employing numerical experiments, we use these observations of X-ray source height motions as a constraint to distinguish between heating due to a non-thermal electron beam and in situ energy deposition in the corona. We find that both heating scenarios can reproduce the observed light curves, but our results favor non-thermal heating. In situ heating is inconsistent with the observed X-ray source morphology and always gives a height dispersion with photon energy opposite to what is observed.

Performance of a static-anode/flat-panel x-ray fluoroscopy system in a diagnostic strength magnetic field: a truly hybrid x-ray/MR imaging system.

Science.gov (United States)

Fahrig, R; Wen, Z; Ganguly, A; DeCrescenzo, G; Rowlands, J A; Stevens, G M; Saunders, R F; Pelc, N J

2005-06-01

Minimally invasive procedures are increasing in variety and frequency, facilitated by advances in imaging technology. Our hybrid imaging system (GE Apollo flat panel, custom Brand x-ray static anode x-ray tube, GE Lunar high-frequency power supply and 0.5 T Signa SP) provides both x-ray and MR imaging capability to guide complex procedures without requiring motion of the patient between two distant gantries. The performance of the x-ray tube in this closely integrated system was evaluated by modeling and measuring both the response of the filament to an externally applied field and the behavior of the electron beam for field strengths and geometries of interest. The performance of the detector was assessed by measuring the slanted-edge modulation transfer function (MTF) and when placed at zero field and at 0.5 T. Measured resonant frequencies of filaments can be approximated using a modified vibrating beam model, and were at frequencies well below the 25 kHz frequency of our generator for our filament geometry. The amplitude of vibration was not sufficient to cause shorting of the filament during operation within the magnetic field. A simple model of electrons in uniform electric and magnetic fields can be used to estimate the deflection of the electron beam on the anode for the fields of interest between 0.2 and 0.5 T. The MTF measured at the detector and the DQE showed no significant difference inside and outside of the magnetic field. With the proper modifications, an x-ray system can be fully integrated with a MR system, with minimal loss of image quality. Any x-ray tube can be assessed for compatibility when placed at a particular location within the field using the models. We have also concluded that a-Si electronics are robust against magnetic fields. Detailed knowledge of the x-ray system installation is required to provide estimates of system operation.

Performance of a static-anode/flat-panel x-ray fluoroscopy system in a diagnostic strength magnetic field: A truly hybrid x-ray/MR imaging system

International Nuclear Information System (INIS)

Fahrig, R.; Wen, Z.; Ganguly, A.; DeCrescenzo, G.; Rowlands, J.A.; Stevens, G.M.; Saunders, R.F.; Pelc, N.J.

2005-01-01

Minimally invasive procedures are increasing in variety and frequency, facilitated by advances in imaging technology. Our hybrid imaging system (GE Apollo TM flat panel, custom Brand x-ray static anode x-ray tube, GE Lunar high-frequency power supply and 0.5 T Signa SP TM ) provides both x-ray and MR imaging capability to guide complex procedures without requiring motion of the patient between two distant gantries. The performance of the x-ray tube in this closely integrated system was evaluated by modeling and measuring both the response of the filament to an externally applied field and the behavior of the electron beam for field strengths and geometries of interest. The performance of the detector was assessed by measuring the slanted-edge modulation transfer function (MTF) and when placed at zero field and at 0.5 T. Measured resonant frequencies of filaments can be approximated using a modified vibrating beam model, and were at frequencies well below the 25 kHz frequency of our generator for our filament geometry. The amplitude of vibration was not sufficient to cause shorting of the filament during operation within the magnetic field. A simple model of electrons in uniform electric and magnetic fields can be used to estimate the deflection of the electron beam on the anode for the fields of interest between 0.2 and 0.5 T. The MTF measured at the detector and the DQE showed no significant difference inside and outside of the magnetic field. With the proper modifications, an x-ray system can be fully integrated with a MR system, with minimal loss of image quality. Any x-ray tube can be assessed for compatibility when placed at a particular location within the field using the models. We have also concluded that a-Si electronics are robust against magnetic fields. Detailed knowledge of the x-ray system installation is required to provide estimates of system operation

Non-thermal recombination - a neglected source of flare hard X-rays and fast electron diagnostics (Corrigendum)

Science.gov (United States)

Brown, J. C.; Mallik, P. C. V.; Badnell, N. R.

2010-06-01

Brown and Mallik (BM) recently claimed that non-thermal recombination (NTR) can be a dominant source of flare hard X-rays (HXRs) from hot coronal and chromospheric sources. However, major discrepancies between the thermal continua predicted by BM and by the Chianti database as well as RHESSI flare data, led us to discover substantial errors in the heuristic expression used by BM to extend the Kramers expressions beyond the hydrogenic case. Here we present the relevant corrected expressions and show the key modified results. We conclude that, in most cases, NTR emission was overestimated by a factor of 1-8 by BM but is typically still large enough (as much as 20-30% of the total emission) to be very important for electron spectral inference and detection of electron spectral features such as low energy cut-offs since the recombination spectra contain sharp edges. For extreme temperature regimes and/or if the Fe abundance were as high as some values claimed, NTR could even be the dominant source of flare HXRs, reducing the electron number and energy budget, problems such as in the extreme coronal HXR source cases reported by e.g. Krucker et al.

NuSTAR Detection of X-Ray Heating Events in the Quiet Sun

Science.gov (United States)

Kuhar, Matej; Krucker, Säm; Glesener, Lindsay; Hannah, Iain G.; Grefenstette, Brian W.; Smith, David M.; Hudson, Hugh S.; White, Stephen M.

2018-04-01

The explanation of the coronal heating problem potentially lies in the existence of nanoflares, numerous small-scale heating events occurring across the whole solar disk. In this Letter, we present the first imaging spectroscopy X-ray observations of three quiet Sun flares during the Nuclear Spectroscopic Telescope ARray (NuSTAR) solar campaigns on 2016 July 26 and 2017 March 21, concurrent with the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) observations. Two of the three events showed time lags of a few minutes between peak X-ray and extreme ultraviolet emissions. Isothermal fits with rather low temperatures in the range 3.2–4.1 MK and emission measures of (0.6–15) × 1044 cm‑3 describe their spectra well, resulting in thermal energies in the range (2–6) × 1026 erg. NuSTAR spectra did not show any signs of a nonthermal or higher temperature component. However, as the estimated upper limits of (hidden) nonthermal energy are comparable to the thermal energy estimates, the lack of a nonthermal component in the observed spectra is not a constraining result. The estimated Geostationary Operational Environmental Satellite (GOES) classes from the fitted values of temperature and emission measure fall between 1/1000 and 1/100 A class level, making them eight orders of magnitude fainter in soft X-ray flux than the largest solar flares.

IMPULSIVE ACCELERATION OF CORONAL MASS EJECTIONS. II. RELATION TO SOFT X-RAY FLARES AND FILAMENT ERUPTIONS

Energy Technology Data Exchange (ETDEWEB)

Bein, B. M.; Berkebile-Stoiser, S.; Veronig, A. M.; Temmer, M. [Kanzelhoehe Observatory-IGAM, Institute of Physics, University of Graz, Universitaetsplatz 5, A-8010 Graz (Austria); Vrsnak, B. [Hvar Observatory, Faculty of Geodesy, University of Zagreb, Kaciceva 26, HR-10000 Zagreb (Croatia)

2012-08-10

Using high time cadence images from the STEREO EUVI, COR1, and COR2 instruments, we derived detailed kinematics of the main acceleration stage for a sample of 95 coronal mass ejections (CMEs) in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher peak accelerations and lower acceleration phase durations, initiation heights, and heights, at which they reach their peak velocities and peak accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME peak acceleration significantly lower values than for events that were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME acceleration duration and negatively correlated with the CME peak acceleration. For the majority of the events the CME acceleration starts before the flare onset (for 75% of the events) and the CME acceleration ends after the soft X-ray (SXR) peak time (for 77% of the events). In {approx}60% of the events, the time difference between the peak time of the flare SXR flux derivative and the peak time of the CME acceleration is smaller than {+-}5 minutes, which hints at a feedback relationship between the CME acceleration and the energy release in the associated flare due to magnetic reconnection.

Investigation of a novel x-ray tube for the calibration of the x-ray crystal spectrometer in the KSTAR machine

International Nuclear Information System (INIS)

Bak, J.G.; Lee, S.G.

2007-01-01

A novel x-ray tube with a line filament has been developed for the in-situ calibration of the x-ray crystal spectrometer (XCS) in the KSTAR machine. The characteristics of the x-ray tube are investigated from the x-ray images obtained by using a pinhole and a CCD detector. It is found that the image has the width of about 0.1 mm, which is much improved as compared with the previous experimental results. In addition, there is a uniform region around the center of the image within its full length of 13.5 mm. This work may lead to the development of a novel x-ray tube with a line focus, which is required for the calibration of the XCS. Experimental results from the investigation of the x-ray tube are presented and the technical issues in a design of the in-situ calibration system using the x-ray tube for the KSTAR XCS are discussed. (author)

Detection of X-ray flares from AX J1714.1-3912, the unidentified source near RX J1713.7-3946

Science.gov (United States)

Miceli, Marco; Bamba, Aya

2018-04-01

Context. Molecular clouds are predicted to emit nonthermal X-rays when they are close to particle-accelerating supernova remnants (SNRs), and the hard X-ray source AX J1714.1-3912, near the SNR RX J1713.7-3946, has long been considered a candidate for diffuse nonthermal emission associated with cosmic rays diffusing from the remnant to a closeby molecular cloud. Aim. We aim at ascertaining the nature of this source by analyzing two dedicated X-ray observations performed with Suzaku and Chandra. Methods: We extracted images from the data in various energy bands, spectra, and light curves and studied the long-term evolution of the X-ray emission on the basis of the 4.5 yr time separation between the two observations. Results: We found that there is no diffuse emission associated with AX J1714.1-3912, which is instead the point-like source CXOU J171343.9-391205. We discovered rapid time variability (timescale 103 s), together with a high intrinsic absorption and a hard nonthermal spectrum (power law with photon index Γ 1.4). We also found that the X-ray flux of the source drops down by 1-2 orders of magnitude on a timescale of a few years. Conclusions: Our results suggest a possible association between AX J1714.1-3912 and a previously unknown supergiant fast X-ray transient, although further follow-up observations are necessary to prove this association definitively.

The first X-ray imaging spectroscopy of quiescent solar active regions with NuSTAR

DEFF Research Database (Denmark)

Hannah, Iain G.; Grefenstette, Brian W.; Smith, David M.

2016-01-01

We present the first observations of quiescent active regions (ARs) using the Nuclear Spectroscopic Telescope Array (NuSTAR), a focusing hard X-ray telescope capable of studying faint solar emission from high-temperature and non-thermal sources. We analyze the first directly imaged and spectrally...... resolved X-rays above 2 keV from non-flaring ARs, observed near the west limb on 2014 November 1. The NuSTAR X-ray images match bright features seen in extreme ultraviolet and soft X-rays. The NuSTAR imaging spectroscopy is consistent with isothermal emission of temperatures 3.1-4.4 MK and emission...

Structural changes of the regulatory proteins bound to the thin filaments in skeletal muscle contraction by X-ray fiber diffraction

International Nuclear Information System (INIS)

Sugimoto, Yasunobu; Takezawa, Yasunori; Matsuo, Tatsuhito; Ueno, Yutaka; Minakata, Shiho; Tanaka, Hidehiro; Wakabayashi, Katsuzo

2008-01-01

In order to clarify the structural changes related to the regulation mechanism in skeletal muscle contraction, the intensity changes of thin filament-based reflections were investigated by X-ray fiber diffraction. The time course and extent of intensity changes of the first to third order troponin (TN)-associated meridional reflections with a basic repeat of 38.4 nm were different for each of these reflections. The intensity of the first and second thin filament layer lines changed in a reciprocal manner both during initial activation and during the force generation process. The axial spacings of the TN-meridional reflections decreased by ∼0.1% upon activation relative to the relaxing state and increased by ∼0.24% in the force generation state, in line with that of the 2.7-nm reflection. Ca 2+ -binding to TN triggered the shortening and a change in the helical symmetry of the thin filaments. Modeling of the structural changes using the intensities of the thin filament-based reflections suggested that the conformation of the globular core domain of TN altered upon activation, undergoing additional conformational changes at the tension plateau. The tail domain of TN moved together with tropomyosin during contraction. The results indicate that the structural changes of regulatory proteins bound to the actin filaments occur in two steps, the first in response to the Ca 2+ -binding and the second induced by actomyosin interaction

X-ray system analysis

International Nuclear Information System (INIS)

Shapiro, J.S.

1985-01-01

An X-ray system tester for measuring anode voltage, cathode voltage, anode current, filament current and line voltage in an X-ray system has a selector which couples one of these analog signals or one of a plurality of processing control signals entered by an operator from a control panel to a digitizing section selectively in accordance with control signals provided to the selector by a computing section. The digitizing section converts the selected signal into a train of pulses having a frequency proportional to the value of the selected signal. These pulses are counted, the counts being used by the computing section to determine the value of the selected signal. This computed value is stored in a computing memory section of the computing section. The computing section is adapted to store a plurality of the sets of signals produced during a corresponding sequence of operational intervals of the X-ray system and determines a measure of the deviation of any selected one of the stored electrical signals over the sequence of operating intervals. Each signal produced during the sequential operational intervals can be recalled to aid analysis of the operation of the X-ray system. (author)

Nonthermal electron-positron pairs and cold matter in the central engines of active galactic nuclei

Science.gov (United States)

Zdziarski, Andrzej A.

1992-01-01

The nonthermal e(+/-) pair model of the central engine of active galactic nuclei (AGNs) is discussed. The model assumes that nonthermal e(+/-) pairs are accelerated to highly relativistic energies in a compact region close to the central black hole and in the vicinity of some cold matter. The model has a small number of free parameters and explains a large body of AGN observations from EUV to soft gamma-rays. In particular, the model explains the existence of the UV bump, the soft X-rays excess, the canonical hard X-ray power law, the spectral hardening above about 10 keV, and some of the variability patterns in the soft and hard X-rays. In addition, the model explains the spectral steepening above about 50 keV seen in NGC 4151.

X-RAY PULSATIONS FROM THE RADIO-QUIET GAMMA-RAY PULSAR IN CTA 1

International Nuclear Information System (INIS)

Caraveo, P. A.; De Luca, A.; Marelli, M.; Bignami, G. F.; Ray, P. S.; Saz Parkinson, P. M.; Kanbach, G.

2010-01-01

Prompted by the Fermi-LAT discovery of a radio-quiet gamma-ray pulsar inside the CTA 1 supernova remnant, we obtained a 130 ks XMM-Newton observation to assess the timing behavior of this pulsar. Exploiting both the unprecedented photon harvest and the contemporary Fermi-LAT timing measurements, a 4.7σ single-peak pulsation is detected, making PSR J0007+7303 the second example, after Geminga, of a radio-quiet gamma-ray pulsar also seen to pulsate in X-rays. Phase-resolved spectroscopy shows that the off-pulse portion of the light curve is dominated by a power-law, non-thermal spectrum, while the X-ray peak emission appears to be mainly of thermal origin, probably from a polar cap heated by magnetospheric return currents, pointing to a hot spot varying throughout the pulsar rotation.

X-RAY OBSERVATIONS OF BOW SHOCKS AROUND RUNAWAY O STARS. THE CASE OF ζ OPH AND BD+43°3654

Energy Technology Data Exchange (ETDEWEB)

Toalá, J. A.; Guerrero, M. A. [Instituto de Astrofísica de Andalucía, IAA-CSIC, Glorieta de la Astronomía s/n, E-18008 Granada (Spain); Oskinova, L. M.; González-Galán, A. [Institute for Physics and Astronomy, University of Potsdam, D-14476 Potsdam (Germany); Ignace, R. [Department of Physics and Astronomy, East Tennessee State University, Johnson City, TN 37614 (United States); Pohl, M., E-mail: toala@iaa.es [Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), Taipei 10617,Taiwan (China)

2016-04-20

Non-thermal radiation has been predicted within bow shocks around runaway stars by recent theoretical works. We present X-ray observations toward the runaway stars ζ Oph by Chandra and Suzaku and of BD+43°3654 by XMM-Newton to search for the presence of non-thermal X-ray emission. We found no evidence of non-thermal emission spatially coincident with the bow shocks; nonetheless, diffuse emission was detected in the vicinity of ζ Oph. After a careful analysis of its spectral characteristics, we conclude that this emission has a thermal nature with a plasma temperature of T ≈ 2 × 10{sup 6} K. The cometary shape of this emission seems to be in line with recent predictions of radiation-hydrodynamic models of runaway stars. The case of BD+43°3654 is puzzling, as non-thermal emission has been reported in a previous work for this source.

Hadronic model for the non-thermal radiation from the binary system AR Scorpii

Science.gov (United States)

Bednarek, W.

2018-05-01

AR Scorpii is a close binary system containing a rotation powered white dwarf and a low-mass M type companion star. This system shows non-thermal emission extending up to the X-ray energy range. We consider hybrid (lepto-hadronic) and pure hadronic models for the high energy non-thermal processes in this binary system. Relativistic electrons and hadrons are assumed to be accelerated in a strongly magnetised, turbulent region formed in collision of a rotating white dwarf magnetosphere and a magnetosphere/dense atmosphere of the M-dwarf star. We propose that the non-thermal X-ray emission is produced either by the primary electrons or the secondary e± pairs from decay of charged pions created in collisions of hadrons with the companion star atmosphere. We show that the accompanying γ-ray emission from decay of neutral pions, which are produced by these same protons, is expected to be on the detectability level of the present and/or the future satellite and Cherenkov telescopes. The γ-ray observations of the binary system AR Sco should allow us to constrain the efficiency of hadron and electron acceleration and also the details of the radiation processes.

Development, Beam characterization and chromosomal effectiveness of X-rays of RBC characteristic X-ray generator

International Nuclear Information System (INIS)

Endo, Satoru; Hoshi, Masaharu; Takada, Jun; Takatsuji, Toshihiro; Ejima, Yosuke; Saigusa, Shin; Tachibana, Akira; Sasaki, Masao S.

2006-01-01

A characteristic hot-filament type X-ray generator was constructed for irradiation of cultured cells. The source provides copper K, iron K, chromium K, molybdenum L, aluminium K and carbon K shell characteristic X-rays. When cultured mouse m5S cells were irradiated and frequencies of dicentrics were fitted to a linear-quadratic model, Y=αD+βD 2 , the chromosomal effectiveness was not a simple function of photon energy. The α-terms increased with the decrease of the photon energy and then decreased with further decrease of the energy with an inflection point at around 10 keV. The β-terms stayed constant for the photon energy down to 10 keV and then increased with further decrease of energy. Below 10 keV, the relative biological effectiveness (RBE) at low doses was proportional to the photon energy, which contrasted to that for high energy X- or γ-rays where the RBE was inversely related with the photon energy. The reversion of the energy dependency occurred at around 1-2 Gy, where the RBE of soft X-rays was insensitive to X-ray energy. The reversion of energy-RBE relation at a moderate dose may shed light on the controversy on energy dependency of RBE of ultrasoft X-rays in cell survival experiments. (author)

A study of solar flare energy transport based on coordinated H-alpha and X-ray observations

International Nuclear Information System (INIS)

Canfield, R.C.; Wulser, J.; Zarro, D.M.; Dennis, B.R.

1991-01-01

The temporal evolution of the ratio between H-alpha to nonthermal hard X-ray emission was investigated using coordinated H-alpha and hard- and soft-X-ray observations of five solar flares (on May 7, June 23, June 24, and June 25, 1980 and on April 30, 1985). These observations were used to estimate the emitted flare energy flux F(H-alpha) in H-alpha, the flux of F(2O) energy deposited by nonthermal electrons with energies above 20 keV, and the pressure p(c) of soft X-ray-emitting plasma as functions of time during the impulsive phase of each flare. It was found that the F(H-alpha)/F(2O) ratio shows a power-law dependence on F(2O), with a slope that differs slightly from that predicted by the static thick-target model of solar transport. Results also indicate that the power-law dependence is modified by hydrostatic pressure effects. 25 refs

Optical and x-ray survey of s-type Markarian galaxies

International Nuclear Information System (INIS)

Hutter, D.J.; Mufson, S.L.

1981-01-01

We report here the results of a study of 23 compact, lineless Markarian galaxies using broadband optical photometry and x-ray satellite observations. Our photometry shows that the sample can be broken into four groups. In one group (Mrk 180, 421, and 501) are composite objects in which a BL Lacertae object is embedded in an elliptical galaxy. For this group, we present the results of multiepoch x-ray observations using the HEAO-1 and -2 satellites. In addition, we use our photometry to decompose the optical emission into nonthermal and galactic components. In the second group are objects showing a small ultraviolet excess relative to normal galaxies. The x-ray survey indicates that the x-ray luminosity of objects in group 2 is much lower than those in group 1. This suggests that there is an intrinsic difference between objects in groups 1 and 2. The third and fourth groups are objects whose colors are indistinguishable from those of normal field galaxies and those of galactic stars, respectively. No x-ray emission was detected from objects in either of these groups

X-ray tube current control

International Nuclear Information System (INIS)

Dupuis, W.A.; Resnick, T.A.

1982-01-01

A closed loop feedback system for controlling the current output of an x-ray tube. The system has circuitry for improving the transient response and stability of the x-ray tube current over a substantial nonlinear portion of the tube current production characteristic. The system includes a reference generator for applying adjustable step function reference signals representing desired tube currents. The system also includes means for instantaneous sensing of actual tube current. An error detector compares the value of actual and reference tube current and produces an error signal as a function of their difference. The system feedback loop includes amplification circuitry for controlling x-ray tube filament dc voltage to regulate tube current as a function of the error signal value. The system also includes compensation circuitry, between the reference generator and the amplification circuitry, to vary the loop gain of the feedback control system as a function of the reference magnitude

Nonthermal Radiation from Supernova Remnant Shocks

Directory of Open Access Journals (Sweden)

Hyesung Kang

2013-09-01

Full Text Available Most of high energy cosmic rays (CRs are thought to be produced by diffusive shock acceleration (DSA at supernova remnants (SNRs within the Galaxy. Fortunately, nonthermal emissions from CR protons and electrons can provide direct observational evidence for such a model and place strong constraints on the complex nonlinear plasma processes in DSA theory. In this study we calculate the energy spectra of CR protons and electrons in Type Ia SNRs, using time-dependent DSA simulations that incorporate phenomenological models for some wave-particle interactions. We demonstrate that the timedependent evolution of the self-amplified magnetic fields, Alfvénic drift, and escape of the highest energy particles affect the energy spectra of accelerated protons and electrons, and so resulting nonthermal radiation spectrum. Especially, the spectral cutoffs in X-ray and γ-ray emission spectra are regulated by the evolution of the highest energy particles, which are injected at the early phase of SNRs. Thus detailed understandings of nonlinear wave-particle interactions and time-dependent DSA simulations of SNRs are crucial in testing the SNR hypothesis for the origin of Galactic cosmic rays.

Discovery of X-Ray Emission from the Crab Pulsar at Pulse Minimum

Science.gov (United States)

Tennant, Allyn F.; Becker, Werner; Juda, Michael; Elsner, Ronald F.; Kolodziejczak, Jeffery J.; Murray, Stephen S.; ODell, Stephen L.; Paerels, Frits; Swartz, Douglas A.

2001-01-01

The Chandra X-Ray Observatory observed the Crab pulsar using the Low-Energy Transmission Grating with the High-Resolution Camera. Time-resolved zeroth-order images reveal that the pulsar emits X-rays at all pulse phases. Analysis of the flux at minimum - most likely non-thermal in origin - places an upper limit (T(sub infinity) < 2.1 MK) on the surface temperature of the underlying neutron star. In addition, analysis of the pulse profile establishes that the error in the Chandra-determined absolute time is quite small, -0.2 +/- 0.1 ms.

44Ti Nucleosynthesis Lines and Hard X-ray Continuum in Young SNRs: from INTEGRAL to Simbol-X

Science.gov (United States)

Renaud, M.; Terrier, R.; Trap, G.; Lebrun, F.; Decourchelle, A.; Vink, J.

2009-05-01

Supemovae and their remnants are the main Galactic nucleosynthesis sites and the privileged sources of Galactic cosmic rays. The youngest of such remnants can be studied through two distinct observational features: 44Ti γ-ray lines and the hard X-ray nonthermal continuum emission. The former gives unique information on the nucleosynthesis conditions occuring during the first stages of the explosion, while the latter provides clues on acceleration processes at supernova remnant shocks. In this contribution, we present new INTEGRAL results on Tycho, the remnant of a historical supernova, and on G1.9+0.3, which has been recently unveiled as the youngest Galactic supernova remnant. Expectations with Simbol-X are also addressed.

44Ti Nucleosynthesis Lines and Hard X-ray Continuum in Young SNRs: from INTEGRAL to Simbol-X

International Nuclear Information System (INIS)

Renaud, M.; Terrier, R.; Lebrun, F.; Trap, G.; Decourchelle, A.; Vink, J.

2009-01-01

Supemovae and their remnants are the main Galactic nucleosynthesis sites and the privileged sources of Galactic cosmic rays. The youngest of such remnants can be studied through two distinct observational features: 44 Tiγ-ray lines and the hard X-ray nonthermal continuum emission. The former gives unique information on the nucleosynthesis conditions occuring during the first stages of the explosion, while the latter provides clues on acceleration processes at supernova remnant shocks. In this contribution, we present new INTEGRAL results on Tycho, the remnant of a historical supernova, and on G1.9+0.3, which has been recently unveiled as the youngest Galactic supernova remnant. Expectations with Simbol-X are also addressed.

Naima: a Python package for inference of particle distribution properties from nonthermal spectra

Science.gov (United States)

Zabalza, V.

2015-07-01

The ultimate goal of the observation of nonthermal emission from astrophysical sources is to understand the underlying particle acceleration and evolution processes, and few tools are publicly available to infer the particle distribution properties from the observed photon spectra from X-ray to VHE gamma rays. Here I present naima, an open source Python package that provides models for nonthermal radiative emission from homogeneous distribution of relativistic electrons and protons. Contributions from synchrotron, inverse Compton, nonthermal bremsstrahlung, and neutral-pion decay can be computed for a series of functional shapes of the particle energy distributions, with the possibility of using user-defined particle distribution functions. In addition, naima provides a set of functions that allow to use these models to fit observed nonthermal spectra through an MCMC procedure, obtaining probability distribution functions for the particle distribution parameters. Here I present the models and methods available in naima and an example of their application to the understanding of a galactic nonthermal source. naima's documentation, including how to install the package, is available at http://naima.readthedocs.org.

High-Energy X-rays from J174545.5-285829, the Cannonball: a Candidate Pulsar Wind Nebula Associated with Sgr a East

Science.gov (United States)

Nynka, Melania; Hailey, Charles J.; Mori, Kaya; Baganoff, Frederick K.; Bauer, Franz E.; Boggs, Steven E.; Craig, William W.; Christensen, Finn E.; Gotthelf, Eric V.; Harrison, Fiona A.;

Plasma dynamics above solar flare soft x-ray loop tops

Energy Technology Data Exchange (ETDEWEB)

Doschek, G. A.; Warren, H. P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); McKenzie, D. E. [Montana State University, Bozeman, MT 59717 (United States)

2014-06-10

We measure non-thermal motions in flare loop tops and above the loop tops using profiles of highly ionized spectral lines of Fe XXIV and Fe XXIII formed at multimillion-degree temperatures. Non-thermal motions that may be due to turbulence or multiple flow regions along the line of sight are extracted from the line profiles. The non-thermal motions are measured for four flares seen at or close to the solar limb. The profile data are obtained using the Extreme-ultraviolet Imaging Spectrometer on the Hinode spacecraft. The multimillion-degree non-thermal motions are between 20 and 60 km s{sup –1} and appear to increase with height above the loop tops. Motions determined from coronal lines (i.e., lines formed at about 1.5 MK) tend to be smaller. The multimillion-degree temperatures in the loop tops and above range from about 11 MK to 15 MK and also tend to increase with height above the bright X-ray-emitting loop tops. The non-thermal motions measured along the line of sight, as well as their apparent increase with height, are supported by Solar Dynamics Observatory Atmospheric Imaging Assembly measurements of turbulent velocities in the plane of the sky.

Spectral Properties, Generation Order Parameters, and Luminosities for Spin-powered X-Ray Pulsars

Science.gov (United States)

Wang, Wei; Zhao, Yongheng

2004-02-01

We show the spectral properties of 15 spin-powered X-ray pulsars, and the correlation between the average power-law photon index and spin-down rate. Generation order parameters (GOPs) based on polar cap models are introduced to characterize the X-ray pulsars. We calculate three definitions of generation order parameters arising from the different effects of magnetic and electric fields on photon absorption during cascade processes, and study the relations between the GOPs and spectral properties of X-ray pulsars. There exists a possible correlation between the photon index and GOP in our pulsar sample. Furthermore, we present a method stemming from the concept of GOPs to estimate the nonthermal X-ray luminosity for spin-powered pulsars. Then X-ray luminosity is calculated in the context of our polar cap accelerator model, which is consistent with most observed X-ray pulsar data. The ratio between the X-ray luminosity estimated by our method and the pulsar's spin-down power is consistent with the LX~10-3Lsd feature.

Non-thermal pressure in the outskirts of Abell 2142

Science.gov (United States)

Fusco-Femiano, Roberto; Lapi, Andrea

2018-03-01

Clumping and turbulence are expected to affect the matter accreted on to the outskirts of galaxy clusters. To determine their impact on the thermodynamic properties of Abell 2142, we perform an analysis of the X-ray temperature data from XMM-Newton via our SuperModel, a state-of-the-art tool for investigating the astrophysics of the intracluster medium already tested on many individual clusters (since Cavaliere, Lapi & Fusco-Femiano 2009). Using the gas density profile corrected for clumpiness derived by Tchernin et al. (2016), we find evidence for the presence of a non-thermal pressure component required to sustain gravity in the cluster outskirts of Abell 2142, that amounts to about 30 per cent of the total pressure at the virial radius. The presence of the non-thermal component implies the gas fraction to be consistent with the universal value at the virial radius and the electron thermal pressure profile to be in good agreement with that inferred from the SZ data. Our results indicate that the presence of gas clumping and of a non-thermal pressure component are both necessary to recover the observed physical properties in the cluster outskirts. Moreover, we stress that an alternative method often exploited in the literature (included Abell 2142) to determine the temperature profile kBT = Pe/ne basing on a combination of the Sunyaev-Zel'dovich (SZ) pressure Pe and of the X-ray electron density ne does not allow us to highlight the presence of non-thermal pressure support in the cluster outskirts.

DYNAMICS INSIDE THE RADIO AND X-RAY CLUSTER CAVITIES OF CYGNUS A AND SIMILAR FRII SOURCES

International Nuclear Information System (INIS)

Mathews, William G.; Guo Fulai

2012-01-01

We describe approximate axisymmetric computations of the dynamical evolution of material inside radio lobes and X-ray cluster gas cavities in Fanaroff-Riley II (FRII) sources such as Cygnus A. All energy is delivered by a jet to the lobe/cavity via a moving hotspot where jet energy dissipates in a reverse shock. Our calculations describe the evolution of hot plasma, cosmic rays (CRs), and toroidal magnetic fields flowing from the hotspot into the cavity. Many important observational features are explained. Gas, CRs, and field flow back along the cavity surface in a 'boundary backflow' consistent with detailed FRII observations. Computed ages of backflowing CRs are consistent with observed radio-synchrotron age variations only if shear instabilities in the boundary backflow are damped and we assume this is done with viscosity of unknown origin. We compute a faint thermal jet along the symmetry axis and suggest that it is responsible for redirecting the Cygnus A nonthermal jet. Magnetic fields estimated from synchrotron self-Compton (SSC) X-radiation observed near the hotspot evolve into radio lobe fields. Computed profiles of radio-synchrotron lobe emission perpendicular to the jet reveal dramatically limb-brightened emission in excellent agreement with FRII observation, although computed lobe fields exceed those observed. Strong winds flowing from hotspots naturally create kiloparsec-sized spatial offsets between hotspot nonthermal X-ray inverse Compton (IC-CMB) emission and radio-synchrotron emission that peaks 1-2 kpc ahead where the field increases due to wind compression. In our computed version of Cygnus A, nonthermal X-ray emission increases from the hotspot (some IC-CMB, mostly SSC) toward the offset radio-synchrotron peak (mostly SSC).

Absence of synergistic enhancement of non-thermal effects of ultrasound on cell killing induced by ionizing radiation

International Nuclear Information System (INIS)

Kondo, T.; Kano, E.

1987-01-01

The present study was performed to elucidate the role of non-thermal effects (cavitation and direct effects) of ultrasound, in simultaneous combination with X-irradiation on the cytotoxicity of mouse L cells. Firstly, mouse L cells were exposed to X-rays and ultrasound (1 MHz continous wave, spatial peak temporal average intensity; 3.7 W/cm 2 ) simultaneously at 37 0 C under O 2 or Ar saturated conditions to examine the cavitational effect of ultrasound. Secondly, cells were exposed to X-rays and ultrasound at 37 0 C under N 2 O saturated conditions, which suppresses the cavitation, to examine the direct effects of ultrasound. The cavitational effect under O 2 and Ar saturated conditions induced an exponential decrease in cell survival, and resulted in an additive effect on cell killing with the combination of X-rays and ultrasound. The direct effect in the N 2 O conditions induced no cell killing and did not modify the cell killing induced by X-rays. These results suggested that the non-thermal effects of ultrasound did not interact synergistically with X-rays for cell killing. (author)

Broadband X-ray spectra of the ultraluminous X-ray source Holmberg IX X-1 observed with NuSTAR, XMM-Newton, and Suzaku

Energy Technology Data Exchange (ETDEWEB)

Walton, D. J.; Harrison, F. A.; Grefenstette, B. W.; Fuerst, F.; Madsen, K. K.; Rana, V.; Stern, D. [Space Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Miller, J. M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States); Bachetti, M.; Barret, D.; Webb, N. [Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France); Boggs, S. E.; Craig, W. W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Fabian, A. C.; Parker, M. L. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Ptak, A.; Zhang, W. W., E-mail: dwalton@srl.caltech.edu [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2014-09-20

We present results from the coordinated broadband X-ray observations of the extreme ultraluminous X-ray source Holmberg IX X-1 performed by NuSTAR, XMM-Newton, and Suzaku in late 2012. These observations provide the first high-quality spectra of Holmberg IX X-1 above 10 keV to date, extending the X-ray coverage of this remarkable source up to ∼30 keV. Broadband observations were undertaken at two epochs, between which Holmberg IX X-1 exhibited both flux and strong spectral variability, increasing in luminosity from L {sub X} = (1.90 ± 0.03) × 10{sup 40} erg s{sup –1} to L {sub X} = (3.35 ± 0.03) × 10{sup 40} erg s{sup –1}. Neither epoch exhibits a spectrum consistent with emission from the standard low/hard accretion state seen in Galactic black hole binaries, which would have been expected if Holmberg IX X-1 harbors a truly massive black hole accreting at substantially sub-Eddington accretion rates. The NuSTAR data confirm that the curvature observed previously in the 3-10 keV bandpass does represent a true spectral cutoff. During each epoch, the spectrum appears to be dominated by two optically thick thermal components, likely associated with an accretion disk. The spectrum also shows some evidence for a nonthermal tail at the highest energies, which may further support this scenario. The available data allow for either of the two thermal components to dominate the spectral evolution, although both scenarios require highly nonstandard behavior for thermal accretion disk emission.

Non-thermal X-rays and interstellar gas toward the γ-ray supernova remnant RX J1713.7–3946: evidence for X-ray enhancement around CO and H I clumps

Energy Technology Data Exchange (ETDEWEB)

Sano, H.; Torii, K.; Fukuda, T.; Yoshiike, S.; Sato, J.; Horachi, H.; Kuwahara, T.; Hayakawa, T.; Matsumoto, H.; Inutsuka, S.; Kawamura, A.; Tachihara, K.; Yamamoto, H.; Okuda, T.; Mizuno, N.; Onishi, T. [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Tanaka, T. [Department of Physics, Kyoto University, Kitashirakawa-oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Inoue, T.; Yamazaki, R. [Department of Physics and Mathematics, Aoyama Gakuin University, Fuchinobe, Chuou-ku, Sagamihara 252-5258 (Japan); Mizuno, A., E-mail: sano@a.phys.nagoya-u.ac.jp [Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); and others

2013-11-20

RX J1713.7–3946 is the most remarkable very high energy γ-ray supernova remnant that emits synchrotron X-rays without thermal features. We made a comparative study of CO, H I, and X-rays in order to better understand the relationship between the X-rays, and the molecular and atomic gas. The results indicate that the X-rays are enhanced around the CO and H I clumps on a pc scale, but are decreased inside the clumps on a 0.1 pc scale. Magnetohydrodynamic numerical simulations of the shock interaction with molecular and atomic gas indicate that the interaction between the shock waves and the clumps excite turbulence, which amplifies the magnetic field around the clumps. We suggest that the amplified magnetic field around the CO and H I clumps enhances the synchrotron X-rays and possibly the acceleration of cosmic-ray electrons.

Miniature X-ray Tube for Electric Brachytherapy using Carbon Nanotube Field Emitter

International Nuclear Information System (INIS)

Heo, Sung Hwan; Kim, Hyun Jin; Ha, Jun Mok; Cho, Sung Oh

2011-01-01

An electric brachytherapy using a miniature x-ray tube has a major advantage to reduce the x-ray exposure of human body during the cancer radiation therapy by optimal positioning of x-ray radiation source and treatment objectives. In the view of a smaller electronic x-ray source, the CNT field emitter based xray tube can be more minimized than thermionic filament emitter based one because of a simple power supplier connection of cold field emission in diode type as well as a higher electron emission brightness of CNT. This abstract is for introducing the design of a prototype CNT field emitter based miniature x-ray tube. We have vacuum sealed CNT miniature x-ray tube with 7∼10 mm diameter, and characteristics of electron emission and x-ray transportation using MCNP5 code are surveyed

Solar X-Ray Processes

Science.gov (United States)

Mallik, P. C. V.; Brown, J. C.; MacKinnon, A. L.

Past analyses of solar flares have ignored nonthermal recombination (NTR) emission as a means of producing Hard X-rays (HXRs) in the corona and chromosphere. However, Brown and Mallik (2008, A&A, 481, 507) have shown that NTR can be significant and even exceed nonthermal bremsstrahlung (NTB) emission for certain flare conditions that are quite common. For hot enough plasma (T > 10 MK), HXR emission of a few deka-keV has a large contribution from NTR onto highly ionized heavy elements, especially Fe. Consequently, including NTR has implications for the magnitude and the form of the inferred electron spectrum, F(E), and hence for fast-electron density and energy budgets and for the acceleration mechanisms. We show under what circumstances NTR dominates in deka-keV HXR emission. It is important to note that at high temperatures, HXR emission from thermal electrons (recombination and bremsstrahlung) becomes important. However, NTR dominates over NTB without being swamped by thermal emission in the photon energy (ɛ) regime of 20-30 keV and temperature range of 10-25MK (Fig. 1, left). By integrating the flux for all ɛ > 20keV, i.e., looking at the source luminosity function above 20 keV, we were able to show that by including NTR, the acceleration requirements are less demanding for every event, but to varying degrees based on temperature (T), spectral index (δ) and electron low-energy cut-off (Ec). Our key result is that, for T > 10MK and δ ≈ 5, including NTR reduces the demand for nonthermal electrons by up to 85%. Our paper with these results will be submitted to ApJ Letters.

An oxygen dependent X-ray lesion in Escherichia coli strain B/r detected by penicillin

International Nuclear Information System (INIS)

Gillies, N.E.; Obioha, F.I.; Ratnajothi, N.H.

1979-01-01

Enhancement of lethal damage to E. coli B/r by penicillin was observed after X-irradiation under aerobic conditions, but not after exposure to X-rays under anoxia or after U.V. (260 nm) irradiation. No enhancement of damage occurred when incubation with penicillin was delayed for 2 hours after aerobic X-irradiation. This enhancing effect was only detected in this strain and not in the filamentous strain E. coli B. It was concluded that an X-ray induced lesion, sensitive to the presence of oxygen at the time of irradiation and probably located in the cell envelope, initiates filamentation in E. coli B/r, which results in lethal damage in this strain. (author)

Cosmic Rays and Non-thermal Emission Induced by Accretion of Cool Gas onto the Galactic Disk

Science.gov (United States)

Inoue, Susumu; Uchiyama, Yasunobu; Arakawa, Masanori; Renaud, Matthieu; Wada, Keiichi

2017-11-01

On both observational and theoretical grounds, the disk of our Galaxy should be accreting cool gas with temperature ≲ {10}5 K via the halo at a rate ˜1 {{M}⊙ {yr}}-1. At least some of this accretion is mediated by high-velocity clouds (HVCs), observed to be traveling in the halo with velocities of a few 100 km s-1 and occasionally impacting the disk at such velocities, especially in the outer regions of the Galaxy. We address the possibility of particle acceleration in shocks triggered by such HVC accretion events, and the detectability of consequent non-thermal emission in the radio to gamma-ray bands and high-energy neutrinos. For plausible shock velocities ˜ 300 {km} {{{s}}}-1 and magnetic field strengths ˜ 0.3{--}10 μ {{G}}, electrons and protons may be accelerated up to ˜1-10 TeV and ˜ 30{--}{10}3 TeV, respectively, in sufficiently strong adiabatic shocks during their lifetime of ˜ {10}6 {{yr}}. The resultant pion decay and inverse Compton gamma-rays may be the origin of some unidentified Galactic GeV-TeV sources, particularly the “dark” source HESS J1503-582 that is spatially coincident with the anomalous H I structure known as “forbidden-velocity wings.” Correlation of their locations with star-forming regions may be weak, absent, or even opposite. Non-thermal radio and X-ray emission from primary and/or secondary electrons may be detectable with deeper observations. The contribution of HVC accretion to Galactic cosmic rays is subdominant, but could be non-negligible in the outer Galaxy. As the thermal emission induced by HVC accretion is likely difficult to detect, observations of such phenomena may offer a unique perspective on probing gas accretion onto the Milky Way and other galaxies.

Statistics of “Cold” Early Impulsive Solar Flares in X-Ray and Microwave Domains

Science.gov (United States)

Lysenko, Alexandra L.; Altyntsev, Alexander T.; Meshalkina, Natalia S.; Zhdanov, Dmitriy; Fleishman, Gregory D.

2018-04-01

Solar flares often happen after a preflare/preheating phase, which is almost or entirely thermal. In contrast, there are the so-called early impulsive flares that do not show a (significant) preflare heating, but instead often show the Neupert effect—a relationship where the impulsive phase is followed by a gradual, cumulative-like, thermal response. This has been interpreted as a dominance of nonthermal energy release at the impulsive phase, even though a similar phenomenology is expected if the thermal and nonthermal energies are released in comparable amounts at the impulsive phase. Nevertheless, some flares do show a good quantitative correspondence between the nonthermal electron energy input and plasma heating; in such cases, the thermal response was weak, which results in them being called “cold” flares. We undertook a systematic search for such events among early impulsive flares registered by the Konus-Wind instrument in the triggered mode from 11/1994 to 4/2017, and selected 27 cold flares based on relationships between hard X-ray (HXR) (Konus-Wind) and soft X-ray (Geostationary Operational Environmental Satellite) emission. For these events, we put together all available microwave data from different instruments. We obtained temporal and spectral parameters of HXR and microwave emissions of the events and examined correlations between them. We found that, compared to a “mean” flare, the cold flares: (i) are weaker, shorter, and harder in the X-ray domain; (ii) are harder and shorter, but not weaker in the microwaves; (iii) have a significantly higher spectral peak frequencies in the microwaves. We discuss the possible physical reasons for these distinctions and implication of the finding.

Electron temperature from x-ray continuum measurements on the NIF

Science.gov (United States)

Jarrott, Leonard; Bachmann, Benjamin; Benedetti, Robin; Izumi, Nobuhiko; Khan, Shahab; Landen, Otto; Ma, Tammy; Nagel, Sabrina; Pak, Arthur; Patel, Prav; Schneider, Marilyn; Springer, Paul; LLNL Collaboration

2017-10-01

We report on measurements of the electron temperature within the hot spot of inertially confined, layered implosions on the NIF using a titanium differential filtering x-ray diagnostic. The electron temperature from x-ray emission is insensitive to non-thermal velocity flows as is the case with ion temperature measurements and is thus a critical parameter in interpreting stagnated hot spot conditions. Here we discuss measurements using titanium filters ranging from 10 μm to 1mm in thickness with a sensitivity band of 10-30keV coupled with penumbral pinholes. The use of larger pinhole diameters increases x-ray fluence improving sensitivity of photon energies with minimal attenuation from the compressed fuel/shell. This diagnostic has been fielded on a series of cryogenic shots with DT ion temperatures ranging from 2-5keV. Analysis of the measurement will be presented along with a comparison against simulated electron temperatures and x-ray spectra as well as a comparison to DT ion temperature measurements. This work was performed under the auspices of U.S. DoE by LLNL under Contract No. DE-AC52-07NA27344.

Probing muscle myosin motor action: x-ray (m3 and m6) interference measurements report motor domain not lever arm movement.

Science.gov (United States)

Knupp, Carlo; Offer, Gerald; Ranatunga, K W; Squire, John M

2009-07-10

The key question in understanding how force and movement are produced in muscle concerns the nature of the cyclic interaction of myosin molecules with actin filaments. The lever arm of the globular head of each myosin molecule is thought in some way to swing axially on the actin-attached motor domain, thus propelling the actin filament past the myosin filament. Recent X-ray diffraction studies of vertebrate muscle, especially those involving the analysis of interference effects between myosin head arrays in the two halves of the thick filaments, have been claimed to prove that the lever arm moves at the same time as the sliding of actin and myosin filaments in response to muscle length or force steps. It was suggested that the sliding of myosin and actin filaments, the level of force produced and the lever arm angle are all directly coupled and that other models of lever arm movement will not fit the X-ray data. Here, we show that, in addition to interference across the A-band, which must be occurring, the observed meridional M3 and M6 X-ray intensity changes can all be explained very well by the changing diffraction effects during filament sliding caused by heads stereospecifically attached to actin moving axially relative to a population of detached or non-stereospecifically attached heads that remain fixed in position relative to the myosin filament backbone. Crucially, and contrary to previous interpretations, the X-ray interference results provide little direct information about the position of the myosin head lever arm; they are, in fact, reporting relative motor domain movements. The implications of the new interpretation are briefly assessed.

THE PLANCK SUNYAEV-ZEL'DOVICH VERSUS THE X-RAY VIEW OF THE COMA CLUSTER

International Nuclear Information System (INIS)

Fusco-Femiano, R.; Lapi, A.; Cavaliere, A.

2013-01-01

The Planck collaboration has recently published precise and resolved measurements of the Sunyaev-Zel'dovich (SZ) effect in Abell 1656 (the Coma cluster of galaxies), thus directly gauging the electron pressure profile in the intracluster plasma. On the other hand, such a quantity may be also derived from combining the density and temperature provided by X-ray observations of the thermal bremsstrahlung radiation emitted by the plasma. We find a model-independent tension between the SZ and the X-ray pressure, with the SZ one being definitely lower by 15%-20%. We propose that such a challenging tension can be resolved in terms of an additional, non-thermal support to the gravitational equilibrium of the intracluster plasma. This can be straightforwardly included in our Supermodel, so as to fit in detail the Planck SZ profile while being consistent with the X-ray observables. Possible origins of the non-thermal component include cosmic-ray protons, ongoing turbulence, and relativistic electrons; given the existing observational constraints on the first two options, here we focus on the third. For this to be effective, we find that the electron population must include not only an energetic tail accelerated to γ ∼> 10 3 responsible for the Coma radiohalo, but also many more, lower energy electrons. The electron acceleration is to be started by merging events similar to those that provided the very high central entropy of the thermal intracluster plasma in Coma.

Neutron and X-ray emission studies in a low energy plasma focus

Energy Technology Data Exchange (ETDEWEB)

Zakaullah, M. [Quaid-i-Azam Univ., Islamabad (Pakistan). Dept. of Physics; Murtaza, G. [Quaid-i-Azam Univ., Islamabad (Pakistan). Dept. of Physics; Qamar, S. [Quaid-i-Azam Univ., Islamabad (Pakistan). Dept. of Physics; Ahmad, I. [Quaid-i-Azam Univ., Islamabad (Pakistan). Dept. of Physics; Beg, M.M. [Quaid-i-Azam Univ., Islamabad (Pakistan). Dept. of Physics

1996-03-01

In a low energy Mather-type plasma focus energized by a single 32 {mu}F capacitor, the X-ray and neutron emission is investigated using time-integrated and time-resolved detectors. The X-ray emission profile has a width (FWHM) of 40-50 ns. The neutron emission profile is broader compared to the X-ray emission profile and also delayed by 30-40 ns. To identify different regimes of X-ray emission, an X-ray pin-hole camera along with different absorption filters is employed. While the X-ray emission is high within a narrow pressure range of 2.0-2.5 mbar, the neutron emission is intense for a wider range of 1.0-4.5 mbar. The intense X-ray emission seems to originate from the axially moving shock wave. These results also indicate rather different production mechanisms for X-ray and neutron emission. Also on comparing the X-ray images with Al(2 {mu}m), Al(5 {mu}m), Al(9 {mu}m) filters, we find that the bulk of X-rays from the focus filament have energies less than 2 keV. (orig.).

X-ray spectroscopic study of high-temperature plasmas by curved crystal spectrometer

International Nuclear Information System (INIS)

Morita, Shigeru.

1983-07-01

Extensive studies have been carried out on the structure of X-ray spectra from the highly stripped ions of first transition elements and their behavior in high temperature plasma, using a high resolution crystal spectrometer. Calculation was made on the design and the use of a curved crystal spectrometer for plasma diagnostics. A Johann type crystal spectrometer for measuring X-ray lines was constructed on the basis of the calculation. The characteristics of curved crystals of LiF, Ge and quartz used for the measurement of Kα lines from first transition elements were investigated. Vacuum sparks have been formed for producing high temperature plasma which emits X-ray lines from highly stripped ions. Two different structures of vacuum spark plasma were shown, that is, thermalized point plasma and extended plasma associated with non-thermal electrons. The X-ray lines from the extended plasma, those associated with the K shell from the point plasma and the Kα lines of Ti through Zn from the point plasma have been observed. (Kako, I.)

Probing the Cosmic X-Ray and MeV Gamma-Ray Background Radiation through the Anisotropy

Energy Technology Data Exchange (ETDEWEB)

Inoue, Yoshiyuki [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Murase, Kohta [Inst. for Advanced Study, Princeton, NJ (United States). School of Natural Sciences; Madejski, Grzegorz M. [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Uchiyama, Yasunobu [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Rikkyo Univ., Tokyo (Japan). Dept. of Physics

2013-09-24

While the cosmic soft X-ray background is very likely to originate from individual Seyfert galaxies, the origin of the cosmic hard X-ray and MeV gamma-ray background is not fully understood. It is expected that Seyferts including Compton thick population may explain the cosmic hard X-ray background. At MeV energy range, Seyferts having non-thermal electrons in coronae above accretion disks or MeV blazars may explain the background radiation. We propose that future measurements of the angular power spectra of anisotropy of the cosmic X-ray and MeV gamma-ray backgrounds will be key to deciphering these backgrounds and the evolution of active galactic nuclei (AGNs). As AGNs trace the cosmic large-scale structure, spatial clustering of AGNs exists. We show that e-ROSITA will clearly detect the correlation signal of unresolved Seyferts at 0.5-2 keV and 2-10 keV bands and will be able to measure the bias parameter of AGNs at both bands. Once the future hard X-ray all sky satellites achieve the sensitivity better than 10^-12 erg/cm²/s^-1 at 10-30 keV or 30-50 keV - although this is beyond the sensitivities of current hard X-ray all sky monitors - angular power spectra will allow us to independently investigate the fraction of Compton-thick AGNs in all Seyferts. We also find that the expected angular power spectra of Seyferts and blazars in the MeV range are different by about an order of magnitude, where the Poisson term, so-called shot noise, is dominant. Current and future MeV instruments will clearly disentangle the origin of the MeV gamma-ray background through the angular power spectrum.

Probing the cosmic x-ray and MeV gamma ray background radiation through the anisotropy

Energy Technology Data Exchange (ETDEWEB)

Inoue, Yoshiyuki [Stanford Univ., CA (United States); Murase, Kohta [Inst. for Advanced Study, Princeton, NJ (United States); Madejski, Grzegorz M. [Stanford Univ., CA (United States); Uchiyama, Yasunobu [Stanford Univ., CA (United States); Rikkyo Univ., Tokyo (Japan)

2013-09-24

While the cosmic soft X-ray background is very likely to originate from individual Seyfert galaxies, the origin of the cosmic hard X-ray and MeV gamma-ray background is not fully understood. It is expected that Seyferts including Compton thick population may explain the cosmic hard X-ray background. At MeV energy range, Seyferts having non-thermal electrons in coronae above accretion disks or MeV blazars may explain the background radiation. We propose that future measurements of the angular power spectra of anisotropy of the cosmic X-ray and MeV gamma-ray backgrounds will be key to deciphering these backgrounds and the evolution of active galactic nuclei (AGNs). As AGNs trace the cosmic large-scale structure, spatial clustering of AGNs exists. We show that e-ROSITA will clearly detect the correlation signal of unresolved Seyferts at 0.5-2 keV and 2-10 keV bands and will be able to measure the bias parameter of AGNs at both bands. Once future hard X-ray all sky satellites achieve a sensitivity better than 10–12 erg cm–2 s–1 at 10-30 keV or 30-50 keV—although this is beyond the sensitivities of current hard X-ray all sky monitors—angular power spectra will allow us to independently investigate the fraction of Compton-thick AGNs in all Seyferts. We also find that the expected angular power spectra of Seyferts and blazars in the MeV range are different by about an order of magnitude, where the Poisson term, so-called shot noise, is dominant. Current and future MeV instruments will clearly disentangle the origin of the MeV gamma-ray background through the angular power spectrum.

Rapid small-angle X-ray diffraction of a tonically contracting molluscan smooth muscle recorded with imaging plates

International Nuclear Information System (INIS)

Tajima, Y.; Okada, K.; Yoshida, O.; Seto, T.; Amemiya, Y.

1989-01-01

Small-angle X-ray diffraction patterns from the anterior byssus retractor muscles of Mytilus edulis contracting tonically in response to stimulation with acetylcholine were recorded in a 30 s exposure with synchrotron radiation and a high-sensitivity X-ray area detector called an imaging plate. The 190 A layer line from the thin filaments increased in intensity with increase in tonic tension up to 6x10 4 kg m -2 . Above this value, the layer-line intensity remained almost constant and comparable to that for a contracting skeletal muscle, indicating that the same structural changes of the thin filaments occur in both muscles. (orig.)

Nonthermal emission from clusters of galaxies

International Nuclear Information System (INIS)

Kushnir, Doron; Waxman, Eli

2009-01-01

We show that the spectral and radial distribution of the nonthermal emission of massive, M ∼> 10 14.5 M ☉ , galaxy clusters may be approximately described by simple analytic expressions, which depend on the cluster thermal X-ray properties and on two model parameter, β core and η e . β core is the ratio of the cosmic-ray (CR) energy density (within a logarithmic CR energy interval) and the thermal energy density at the cluster core, and η e(p) is the fraction of the thermal energy generated in strong collisionless shocks, which is deposited in CR electrons (protons). Using a simple analytic model for the evolution of intra-cluster medium CRs, which are produced by accretion shocks, we find that β core ≅ η p /200, nearly independent of cluster mass and with a scatter Δln β core ≅ 1 between clusters of given mass. We show that the hard X-ray (HXR) and γ-ray luminosities produced by inverse Compton scattering of CMB photons by electrons accelerated in accretion shocks (primary electrons) exceed the luminosities produced by secondary particles (generated in hadronic interactions within the cluster) by factors ≅ 500(η e /η p )(T/10 keV) −1/2 and ≅ 150(η e /η p )(T/10 keV) −1/2 respectively, where T is the cluster temperature. Secondary particle emission may dominate at the radio and very high energy (∼> 1 TeV) γ-ray bands. Our model predicts, in contrast with some earlier work, that the HXR and γ-ray emission from clusters of galaxies are extended, since the emission is dominated at these energies by primary (rather than by secondary) electrons. Our predictions are consistent with the observed nonthermal emission of the Coma cluster for η p ∼ η e ∼ 0.1. The implications of our predictions to future HXR observations (e.g. by NuStar, Simbol-X) and to (space/ground based) γ-ray observations (e.g. by Fermi, HESS, MAGIC, VERITAS) are discussed. In particular, we identify the clusters which are the best candidates for detection in γ-rays

Nonthermal emission from clusters of galaxies

Science.gov (United States)

Kushnir, Doron; Waxman, Eli

2009-08-01

We show that the spectral and radial distribution of the nonthermal emission of massive, M gtrsim 1014.5Msun, galaxy clusters may be approximately described by simple analytic expressions, which depend on the cluster thermal X-ray properties and on two model parameter, βcore and ηe. βcore is the ratio of the cosmic-ray (CR) energy density (within a logarithmic CR energy interval) and the thermal energy density at the cluster core, and ηe(p) is the fraction of the thermal energy generated in strong collisionless shocks, which is deposited in CR electrons (protons). Using a simple analytic model for the evolution of intra-cluster medium CRs, which are produced by accretion shocks, we find that βcore simeq ηp/200, nearly independent of cluster mass and with a scatter Δln βcore simeq 1 between clusters of given mass. We show that the hard X-ray (HXR) and γ-ray luminosities produced by inverse Compton scattering of CMB photons by electrons accelerated in accretion shocks (primary electrons) exceed the luminosities produced by secondary particles (generated in hadronic interactions within the cluster) by factors simeq 500(ηe/ηp)(T/10 keV)-1/2 and simeq 150(ηe/ηp)(T/10 keV)-1/2 respectively, where T is the cluster temperature. Secondary particle emission may dominate at the radio and very high energy (gtrsim 1 TeV) γ-ray bands. Our model predicts, in contrast with some earlier work, that the HXR and γ-ray emission from clusters of galaxies are extended, since the emission is dominated at these energies by primary (rather than by secondary) electrons. Our predictions are consistent with the observed nonthermal emission of the Coma cluster for ηp ~ ηe ~ 0.1. The implications of our predictions to future HXR observations (e.g. by NuStar, Simbol-X) and to (space/ground based) γ-ray observations (e.g. by Fermi, HESS, MAGIC, VERITAS) are discussed. In particular, we identify the clusters which are the best candidates for detection in γ-rays. Finally, we show

NuSTAR hard X-ray observations of the Jovian magnetosphere during Juno perijove and apojove intervals

Science.gov (United States)

Dunn, W.; Mori, K.; Hailey, C. J.; Branduardi-Raymont, G.; Grefenstette, B.; Jackman, C. M.; Hord, B. J.; Ray, L. C.

2017-12-01

The Nuclear Spectroscopic Telescope Array (NuSTAR) is the first focusing hard X-ray telescope operating in the 3-79 keV band with sub-arcminute angular resolution (18" FWHM). For the first time, NuSTAR provides sufficient sensitivity to detect/resolve hard X-ray emission from Jupiter above 10 keV, since the in-situ Ulysses observation failed to detect X-ray emission in the 27-48 keV band [Hurley et al. 1993]. The initial, exploratory NuSTAR observation of Jupiter was performed in February 2015 with 100 ksec exposure. NuSTAR detected hard X-ray emission (E > 10 keV) from the south polar region at a marginally significance of 3 sigma level [Mori et al. 2016, AAS meeting poster]. This hard X-ray emission is likely an extension of the non-thermal bremsstrahlung component detected up to 7 keV by XMM-Newton [Branduardi-Raymont et al. 2007]. The Ulysses non-detection suggests there should be a spectral cutoff between 7 and 27 keV. Most intriguingly, the NuSTAR detection of hard X-ray emission from the south aurora is in contrast to the 2003 XMM-Newton observations where soft X-ray emission below 8 keV was seen from both the north and south poles [Gladstone et al. 2002]. Given the marginal, but tantalizing, hard X-ray detection of the southern Jovian aurora, a series of NuSTAR observations with total exposure of nearly half a million seconds were approved in the NuSTAR GO and DDT program. These NuSTAR observations coincided with one Juno apojove (in June 2017) and three perijoves (in May, July and September 2017), also joining the multi-wavelength campaigns of observing Jupiter coordinating with Chandra and XMM-Newton X-ray telescope (below 10 keV) and HST. We will present NuSTAR imaging, spectral and timing analysis of Jupiter. NuSTAR imaging analysis will map hard X-ray emission in comparison with soft X-ray and UV images. In addition to investigating any distinctions between the soft and hard X-ray morphology of the Jovian aurorae, we will probe whether hard X-ray

Continuous reduction of cyclic adsorbed and desorbed NO{sub x} in diesel emission using nonthermal plasma

Energy Technology Data Exchange (ETDEWEB)

Kuwahara, Takuya [Department of Products Engineering and Environmental Management, Nippon Institute of Technology, 4-1 Gakuendai, Miyashiro-machi, Minamisaitama, Saitama 345-8501 (Japan); Nakaguchi, Harunobu; Kuroki, Tomoyuki [Department of Mechanical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531 (Japan); Okubo, Masaaki, E-mail: mokubo@me.osakafu-u.ac.jp [Department of Mechanical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531 (Japan)

2016-05-05

Highlights: • High-efficiency continuous diesel NO{sub x} reduction method is proposed. • Characteristics of diesel NO{sub x} adsorption and desorption on adsorbent is provided. • Efficiency of NO{sub x} reduction with nonthermal plasma is evaluated. • Efficiency of NO{sub x} reduction with exhaust gas component recirculation is evaluated. • High NO{sub x} removal efficiency equal to only 1.0% penalty of engine power is achieved. - Abstract: Considering the recent stringent regulations governing diesel NO{sub x} emission, an aftertreatment system for the reduction of NO{sub x} in the exhaust gas has been proposed and studied. The proposed system is a hybrid method combining nonthermal plasma and NO{sub x} adsorbent. The system does not require precious metal catalysts or harmful chemicals such as urea and ammonia. In the present system, NO{sub x} in diesel emission is treated by adsorption and desorption by adsorbent as well as nonthermal plasma reduction. In addition, the remaining NO{sub x} in the adsorbent is desorbed again in the supplied air by residual heat. The desorbed NO{sub x} in air recirculates into the intake of the engine, and this process, i.e., exhaust gas components’ recirculation (EGCR) achieves NO{sub x} reduction. Alternate utilization of two adsorption chambers in the system can achieve high-efficiency NO{sub x} removal continuously. An experiment with a stationary diesel engine for electric power generation demonstrates an energy efficiency of 154 g(NO{sub 2})/kWh for NO{sub x} removal and continuous NO{sub x} reduction of 70.3%. Considering the regulation against diesel emission in Japan, i.e., the new regulation to be imposed on vehicles of 3.5–7.5 ton since 2016, the present aftertreatment system fulfills the requirement with only 1.0% of engine power.

The Swift BAT Perspective on Non-Thermal Emission in HIFLUGCS Galaxy Clusters

Science.gov (United States)

Wik, Daniel R.

2011-01-01

The search for diffuse non-thermal, inverse Compton (IC) emission from galaxy clusters at hard X-ray energies has been underway for many years, with most detections being either of low significance or controversial. Until recently, comprehensive surveys of hard X-ray emission from clusters were not possible; instead, individually proposed-for. long observations would be collated from the archive. With the advent of the Swift BAT all sky survey, any c1u,;ter's emission above 14 keV can be probed with nearly uniform sensitivity. which is comparable to that of RXTE, Beppo-SAX, and Suzaku with the 58-month version of the survey. In this work. we search for non-thermal excess emission above the exponentially decreasing, high energy thermal emission in the flux-limited HIFLUGCS sample. The BAT emission from many of the detected clusters is marginally extended; we are able to extract the total flux for these clusters using fiducial models for their spatial extent. To account for thermal emission at BAT energies, XMM-Newton EPIC spectra are extracted from coincident spatial regions so that both the thermal and non-thermal spectral components can be determined simultaneou,;ly in joint fits. We find marginally significant IC components in 6 clusters, though after closer inspection and consideration of systematic errors we are unable to claim a clear detection in any of them. The spectra of all clusters are also summed to enhance a cumulative non-thermal signal not quite detectable in individual clusters. After constructing a model based on single temperature

Microwave, EUV, and X-ray observations of active region loops and filaments

International Nuclear Information System (INIS)

Schmahl, E.

1980-01-01

Until the advent of X-ray and EUV observations of coronal structures, radio observers were forced to rely on eclipse and coronagraph observations in white light and forbidden coronal lines for additional diagnostics of the high temperature microwave sources. While these data provided enough material for theoretical insight into the physics of active regions, there was no way to make direct, simultaneous comparison of coronal structures on the disk as seen at microwave and optical wavelengths. This is now possible, and therefore the author summarizes the EUV and X-ray observations indicating at each point the relevance to microwaves. (Auth.)

NuSTAR Study of Hard X-ray Morphology and Spectroscopy G21.5-0.9

Science.gov (United States)

Nynka, Melania; Hailey, Charles J.; Reynolds, Stephen P.; An, Hongjun; Baganoff, Frederick K.; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Gotthelf, Eric V.; Grefenstette, Brian W.;

Relationship between the intensity of nonthermal radiation and widths of Balmer lines in the spectra of quasar-like nuclei

International Nuclear Information System (INIS)

Komberg, B.V.; Shefer, E.Yu.

1983-01-01

The data summarized by Steiner (1981) were used to derive the relationship between the intensity of nonthermal X-ray and radio emission and fullwidths of Balmer emission lines. It is shown that the existence of such dependences does not contradict the assumption on partition equidistribution of nonthermal radiation and motion of gas clouds energy in the region of formation of wide lines. Emphasis is given to similar dependence drived by Vayana (1981) for X-ray radiation from hot coronas of fast-rotating single stars, and a suggestion is made about radiation anisotropy from active nuclei (similar to that observed in the SS 433 system). The latter may imply the double nature of active nuclei

Discovery of Diffuse Hard X-ray Emission associated with Jupiter

Science.gov (United States)

Ezoe, Y.; Miyoshi, Y.; Ishikawa, K.; Ohashi, T.; Terada, N.; Uchiyama, Y.; Negoro, H.

2009-12-01

Our discovery of diffuse hard (1-5 keV) X-ray emission around Jupiter is reported. Recent Chandra and XMM-Newton observations revealed several types of X-rays in the vicinity of Jupiter such as auroral and disk emission from Jupiter and faint diffuse X-rays from the Io Plasma Torus (see Bhardwaj et al. 2007 for review). To investigate possible diffuse hard X-ray emission around Jupiter with the highest sensitivity, we conducted data analysis of Suzaku XIS observations of Jupiter on Feb 2006. After removing satellite and planetary orbital motions, we detected a significant diffuse X-ray emission extending to ~6 x 3 arcmin with the 1-5 keV X-ray luminosity of ~3e15 erg/s. The emitting region very well coincided with the Jupiter's radiation belts. The 1-5 keV X-ray spectrum was represented by a simple power law model with a photon index of 1.4. Such a flat continuum strongly suggests non-thermal origin. Although such an emission can be originated from multiple background point sources, its possibility is quite low. We hence examined three mechanisms, assuming that the emission is truly diffuse: bremsstrahlung by keV electrons, synchrotron emission by TeV electrons, and inverse Compton scattering of solar photons by MeV electrons. The former two can be rejected because of the X-ray spectral shape and implausible existence of TeV electrons around Jupiter, respectively. The last possibility was found to be possible because tens MeV electrons, which have been confirmed in inner radiation belts (Bolton et al. 2002), can kick solar photons to the keV energy range and provide a simple power-law continuum. We estimated an average electron density from the X-ray luminosity assuming the oblate spheroid shaped emitting region with 8 x 8 x 4 Jovian radii. The necessary density was 0.02 1/cm3 for 50 MeV electrons. Hence, our results may suggest a new particle acceleration phenomenon around Jupiter.

Impulsive behavior in solar soft X-radiation

Science.gov (United States)

Hudson, H. S.; Strong, K. T.; Dennis, B. R.; Zarro, D.; Inda, M.; Kosugi, T.; Sakao, T.

1994-01-01

The Yohkoh soft X-ray telescope has observed impulsive, thermal, soft X-ray emission at the footpoints of magnetic loops during solar flares. The soft X-ray (thermal) time profiles at the footpoints closely match the hard X-ray (nonthermal) time profiles, directly demonstrating the heating of the lower solar atmosphere on short timescales during the interval of nonthermal energy release. This phenomenon is the rule, rather than the exception, occurring in the majority of flares that we have examined with the Yohkoh data. We illustrate the impulsive behavior with data from the major flare of 1992 January 26. For this flare, the soft X-ray peak times matched the hard X-ray peak times within the time resolution of the soft X-ray measurements (about 10 s), and the soft and hard X-ray locations match within the resolution of the hard X-ray imager. The impulsive soft X-ray emission clearly has a thermal spectral signature, but not at the high temperature of a 'superhot' source. We conclude that the impulsive soft X-ray emission comes from material heated by precipitating electrons at loop footpoints and evaporating from the deeper atmosphere into the flaring flux tube.

Spectral evolution of active galactic nuclei: A unified description of the X-ray and gamma-ray backgrounds

International Nuclear Information System (INIS)

Letter, D.; Boldt, E.

1982-01-01

A model for spectral evolution is presented whereby active galactic nuclei (AGN) of the type observed individually have emerged from an earlier stage at zroughly-equal4 in which they are the thermal X-ray sources responsible for most of the comic X-ray background (CXB). We pursue the conjecture that these precursor objects are initially supermassive Schwarzschild black holes with accretion disks radiating near the Eddington luminosity limit. It is noted that after approx.10 8 years these central black holes are spun up to a ''canonical'' Kerr equilibriuim state (a/M = 0.998) and shown how they can lead to spectral evolution involving nonthermal emission extending to gamma-rays, at the expense of reduced thermal disk radiation. A superposition of sources in the precursor stage can thereby account for that major portion of the CXB remaining after the contributions of usual AGN are considered, while a superposition of AGN sources at z<1 can account for the gamima-ray background. Extensive X-ray measurements carried out with the HEAO 1 and HEAO 2 missions, as well as gamma-ray and optical data, are shown to compare favorably with principal features of this model. Several further observational tests are suggested for establishing the validity of this scenario for AGN spectral evolution

Line x-ray source for diffraction enhanced imaging in clinical and industrial applications

Science.gov (United States)

Wang, Xiaoqin

Mammography is one type of imaging modalities that uses a low-dose x-ray or other radiation sources for examination of breasts. It plays a central role in early detection of breast cancers. The material similarity of tumor-cell and health cell, breast implants surgery and other factors, make the breast cancers hard to visualize and detect. Diffraction enhanced imaging (DEI), first proposed and investigated by D. Chapman is a new x-ray radiographic imaging modality using monochromatic x-rays from a synchrotron source, which produced images of thick absorbing objects that are almost completely free of scatter. It shows dramatically improved contrast over standard imaging when applied to the same phantom. The contrast is based not only on attenuation but also on the refraction and diffraction properties of the sample. This imaging method may improve image quality of mammography, other medical applications, industrial radiography for non-destructive testing and x-ray computed tomography. However, the size, and cost, of a synchrotron source limits the application of the new modality to be applicable at clinical levels. This research investigates the feasibility of a designed line x-ray source to produce intensity compatible to synchrotron sources. It is composed of a 2-cm in length tungsten filament, installed on a carbon steel filament cup (backing plate), as the cathode and a stationary oxygen-free copper anode with molybdenum coating on the front surface serves as the target. Characteristic properties of the line x-ray source were computationally studied and the prototype was experimentally investigated. SIMIION code was used to computationally study the electron trajectories emanating from the filament towards the molybdenum target. A Faraday cup on the prototype device, proof-of-principle, was used to measure the distribution of electrons on the target, which compares favorably to computational results. The intensities of characteristic x-ray for molybdenum

Hard X-ray emission from accretion shocks around galaxy clusters

Science.gov (United States)

Kushnir, Doron; Waxman, Eli

2010-02-01

We show that the hard X-ray (HXR) emission observed from several galaxy clusters is consistent with a simple model, in which the nonthermal emission is produced by inverse Compton scattering of cosmic microwave background photons by electrons accelerated in cluster accretion shocks: The dependence of HXR surface brightness on cluster temperature is consistent with that predicted by the model, and the observed HXR luminosity is consistent with the fraction of shock thermal energy deposited in relativistic electrons being lesssim0.1. Alternative models, where the HXR emission is predicted to be correlated with the cluster thermal emission, are disfavored by the data. The implications of our predictions to future HXR observations (e.g. by NuStar, Simbol-X) and to (space/ground based) γ-ray observations (e.g. by Fermi, HESS, MAGIC, VERITAS) are discussed.

Hard X-ray emission from accretion shocks around galaxy clusters

Energy Technology Data Exchange (ETDEWEB)

Kushnir, Doron; Waxman, Eli, E-mail: doron.kushnir@weizmann.ac.il, E-mail: eli.waxman@weizmann.ac.il [Physics Faculty, Weizmann Institute of Science, PO Box 26, Rehovot (Israel)

2010-02-01

We show that the hard X-ray (HXR) emission observed from several galaxy clusters is consistent with a simple model, in which the nonthermal emission is produced by inverse Compton scattering of cosmic microwave background photons by electrons accelerated in cluster accretion shocks: The dependence of HXR surface brightness on cluster temperature is consistent with that predicted by the model, and the observed HXR luminosity is consistent with the fraction of shock thermal energy deposited in relativistic electrons being ∼<0.1. Alternative models, where the HXR emission is predicted to be correlated with the cluster thermal emission, are disfavored by the data. The implications of our predictions to future HXR observations (e.g. by NuStar, Simbol-X) and to (space/ground based) γ-ray observations (e.g. by Fermi, HESS, MAGIC, VERITAS) are discussed.

Hard X-ray emission from accretion shocks around galaxy clusters

International Nuclear Information System (INIS)

Kushnir, Doron; Waxman, Eli

2010-01-01

We show that the hard X-ray (HXR) emission observed from several galaxy clusters is consistent with a simple model, in which the nonthermal emission is produced by inverse Compton scattering of cosmic microwave background photons by electrons accelerated in cluster accretion shocks: The dependence of HXR surface brightness on cluster temperature is consistent with that predicted by the model, and the observed HXR luminosity is consistent with the fraction of shock thermal energy deposited in relativistic electrons being ∼<0.1. Alternative models, where the HXR emission is predicted to be correlated with the cluster thermal emission, are disfavored by the data. The implications of our predictions to future HXR observations (e.g. by NuStar, Simbol-X) and to (space/ground based) γ-ray observations (e.g. by Fermi, HESS, MAGIC, VERITAS) are discussed

The "Sigmoid Sniffer” and the "Advanced Automated Solar Filament Detection and Characterization Code” Modules

Science.gov (United States)

Raouafi, Noureddine; Bernasconi, P. N.; Georgoulis, M. K.

2010-05-01

We present two pattern recognition algorithms, the "Sigmoid Sniffer” and the "Advanced Automated Solar Filament Detection and Characterization Code,” that are among the Feature Finding modules of the Solar Dynamic Observatory: 1) Coronal sigmoids visible in X-rays and the EUV are the result of highly twisted magnetic fields. They can occur anywhere on the solar disk and are closely related to solar eruptive activity (e.g., flares, CMEs). Their appearance is typically synonym of imminent solar eruptions, so they can serve as a tool to forecast solar activity. Automatic X-ray sigmoid identification offers an unbiased way of detecting short-to-mid term CME precursors. The "Sigmoid Sniffer” module is capable of automatically detecting sigmoids in full-disk X-ray images and determining their chirality, as well as other characteristics. It uses multiple thresholds to identify persistent bright structures on a full-disk X-ray image of the Sun. We plan to apply the code to X-ray images from Hinode/XRT, as well as on SDO/AIA images. When implemented in a near real-time environment, the Sigmoid Sniffer could allow 3-7 day forecasts of CMEs and their potential to cause major geomagnetic storms. 2)The "Advanced Automated Solar Filament Detection and Characterization Code” aims to identify, classify, and track solar filaments in full-disk Hα images. The code can reliably identify filaments; determine their chirality and other relevant parameters like filament area, length, and average orientation with respect to the equator. It is also capable of tracking the day-by-day evolution of filaments as they traverse the visible disk. The code was tested by analyzing daily Hα images taken at the Big Bear Solar Observatory from mid-2000 to early-2005. It identified and established the chirality of thousands of filaments without human intervention.

A hard x-ray spectrometer for high angular resolution observations of cosmic sources

International Nuclear Information System (INIS)

Hailey, C.J.; Ziock, K.P.; Harrison, F.; Kahn, S.M.; Liedahl, D.; Lubin, P.M.; Seiffert, M.

1988-01-01

LAXRIS (large area x-ray imaging spectrometer) is an experimental, balloon-borne, hard x-ray telescope that consists of a coaligned array of x-ray imaging spectrometer modules capable of obtaining high angular resolution (1--3 arcminutes) with moderate energy resolution in the 20- to 300-keV region. Each spectrometer module consists of a CsI(Na) crystal coupled to a position-sensitive phototube with a crossed-wire, resistive readout. Imaging is provided by a coded aperture mask with a 4-m focal length. The high angular resolution is coupled with rather large area (/approximately/800 cm 2 ) to provide good sensitivity. Results are presented on performance and overall design. Sensitivity estimates are derived from a Monte-Carlo code developed to model the LAXRIS response to background encountered at balloon altitudes. We discuss a variety of observations made feasible by high angular resolution. For instance, spatially resolving the nonthermal x-ray emission from clusters of galaxies is suggested as an ideal program for LAXRIS. 15 refs., 5 figs

Evaluation of components of X-ray irradiated 7-valent pneumococcal conjugate vaccine and pneumococcal vaccine polyvalent and X-ray and gamma-ray irradiated acellular pertussis component of DTaP vaccine products

International Nuclear Information System (INIS)

May, J.C.; Rey, L.; Lee, C.-J.; Arciniega, Juan

2004-01-01

Samples of pneumococcal vaccine polyvalent, 7-valent pneumococcal conjugate vaccine, and two different diphtheria and tetanus toxoids and acellular pertussis vaccines adsorbed were irradiated with X-rays and/or gamma-rays (Co-60). Mouse IgG and IgM antibody responses (ELISA) for types 9V, 14, 18C, and 19F pneumococcal polysaccharides and conjugates indicated that the polysaccharides were more tolerant of the radiation than the conjugates. The mouse antibody response for the detoxified pertussis toxin (PT) antigen, filamentous hemagglutinin antigen (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM) antigens for the appropriate vaccine type indicated that the antibody response was not significantly changed in the 25 kGy X-ray irradiated vaccines frozen in liquid nitrogen compared to the control vaccine

Evaluation of components of X-ray irradiated 7-valent pneumococcal conjugate vaccine and pneumococcal vaccine polyvalent and X-ray and gamma-ray irradiated acellular pertussis component of DTaP vaccine products

Energy Technology Data Exchange (ETDEWEB)

May, J.C. E-mail: may@cber.fda.gov; Rey, L. E-mail: louis.rey@bluewin.ch; Lee, C.-J.; Arciniega, Juan

2004-10-01

Samples of pneumococcal vaccine polyvalent, 7-valent pneumococcal conjugate vaccine, and two different diphtheria and tetanus toxoids and acellular pertussis vaccines adsorbed were irradiated with X-rays and/or gamma-rays (Co-60). Mouse IgG and IgM antibody responses (ELISA) for types 9V, 14, 18C, and 19F pneumococcal polysaccharides and conjugates indicated that the polysaccharides were more tolerant of the radiation than the conjugates. The mouse antibody response for the detoxified pertussis toxin (PT) antigen, filamentous hemagglutinin antigen (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM) antigens for the appropriate vaccine type indicated that the antibody response was not significantly changed in the 25 kGy X-ray irradiated vaccines frozen in liquid nitrogen compared to the control vaccine.

Soft X-ray emission from the radio pulsar PSR 0656 + 14

Science.gov (United States)

Cordova, F. A.; Middleditch, J.; Hjellming, R. M.; Mason, K. O.

1989-01-01

A radio source with a flux density of a few mJy was found in the error region of the soft X-ray source E0656 + 14, and identified as the radio pulsar PSR 0656 + 14. The radio source has a steep, nonthermal spectrum and a high degree of linear (62 percent) and circular (19 percent) polarization. The X-ray spectrum of the pulsar is among the softest sources observed with the Einstein Observatory. The X-ray data taken with the Einstein imaging proportional counter (IPC) permit a range of blackbody temperatures of 3-6 x 10 to the 5th K, and an equivalent column density of hydrogen smaller than 4 x 10 to the 20th/sq cm. If the assumption is made that the X-ray flux is thermal radiation from surface of the neutron star, then the pulsar must be at a distance smaller than 550 pc, consistent with the low dispersion measure of PSR 0656 + 14. The X-ray timing data suggest that the X-ray emission is modulated at the pulsar's 0.385-s spin period with an amplitude of 18 percent + or - 6 percent, and that there is a 0.0002 probability that this is spurious. It was noted that PSR 0656 + 14 is close to the geometric center of a 20-deg diameter soft X-ray emitting ring called the Gemini-Monoceros enhancement. The close distance of the pulsar, together with its relatively young age of 1.1 x 10 to the 5th yr, makes it possible that the ring is a supernova remnant from the explosion of the pulsar's progenitor. A radio source extending over a region 1.2 to 3.3 arcmin south of the pulsar is a candidate for association with the pulsar.

Soft X-ray emission from the radio pulsar PSR 0656 + 14

International Nuclear Information System (INIS)

Cordova, F.A.; Middleditch, J.; Hjellming, R.M.; Mason, K.O.

1989-01-01

A radio source with a flux density of a few mJy was found in the error region of the soft X-ray source E0656 + 14, and identified as the radio pulsar PSR 0656 + 14. The radio source has a steep, nonthermal spectrum and a high degree of linear (62%) and circular (19%) polarization. The X-ray spectrum of the pulsar is among the softest sources observed with the Einstein Observatory. The X-ray data taken with the Einstein imaging proportional counter (IPC) permit a range of blackbody temperatures of 3-6 x 10 to the 5th K, and an equivalent column density of hydrogen smaller than 4 x 10 to the 20th/sq cm. If the assumption is made that the X-ray flux is thermal radiation from surface of the neutron star, then the pulsar must be at a distance smaller than 550 pc, consistent with the low dispersion measure of PSR 0656 + 14. The X-ray timing data suggest that the X-ray emission is modulated at the pulsar's 0.385-s spin period with an amplitude of 18% + or - 6%, and that there is a 0.0002 probability that this is spurious. It was noted that PSR 0656 + 14 is close to the geometric center of a 20-deg diameter soft X-ray emitting ring called the Gemini-Monoceros enhancement. The close distance of the pulsar, together with its relatively young age of 1.1 x 10 to the 5th yr, makes it possible that the ring is a supernova remnant from the explosion of the pulsar's progenitor. A radio source extending over a region 1.2 to 3.3 arcmin south of the pulsar is a candidate for association with the pulsar. 46 refs

Plasma spectroscopy diagnostics in pulsed-power X-ray radiography diode research

International Nuclear Information System (INIS)

Maron, Yitzhak; Oliver, Bryan Velten; Portillo, Salvador; Johnston, Mark D.; Rose, David Vincent; Hahn, Kelly Denise; Schamiloglu, Edl; Welch, Dale R.; Droemer, Darryl W.; Rovang, Dean Curtis; Maenchen, John Eric

2005-01-01

Spectroscopic investigations in the visible and near UV are underway to study plasmas present in X-ray radiography diodes during the time of the electron beam propagation. These studies are being performed on the RITS-3 accelerator (5.25 MV and 120 kA) at Sandia National Laboratories using several diode configurations. The proper characterization of the plasmas occurring during the time of the X-ray pulse can lead to a greater understanding of diode behavior and X-ray spot size evolution. By studying these plasmas along with the use of selective dopants, insights into such phenomena as impedance collapse, thermal and non-thermal species behavior, charge and current neutralization, anode and cathode plasma formation and propagation, and beam/foil interactions, can be obtained. Information from line and continuum emission and absorption can give key plasma parameters such as temperatures, densities, charge states, and expansion velocities. This information is important for proper modeling and future predictive capabilities for the design and improvement of flash X-ray radiography diodes. Diagnostics include a gated, intensified multichannel plate camera combined with a 1 meter Czerny-Turner monochromator with a multi-fiber spectral input, allowing for both temporal and spatial resolution. Recent results are presented.

FreeDam - A webtool for free-electron laser-induced damage in femtosecond X-ray crystallography

Science.gov (United States)

Jönsson, H. Olof; Östlin, Christofer; Scott, Howard A.; Chapman, Henry N.; Aplin, Steve J.; Tîmneanu, Nicuşor; Caleman, Carl

2018-03-01

Over the last decade X-ray free-electron laser (XFEL) sources have been made available to the scientific community. One of the most successful uses of these new machines has been protein crystallography. When samples are exposed to the intense short X-ray pulses provided by the XFELs, the sample quickly becomes highly ionized and the atomic structure is affected. Here we present a webtool dubbed FreeDam based on non-thermal plasma simulations, for estimation of radiation damage in free-electron laser experiments in terms of ionization, temperatures and atomic displacements. The aim is to make this tool easily accessible to scientists who are planning and performing experiments at XFELs.

Comparison of hard X-ray spectra obtained by spectrometers on Hinotori and SMM and detection of 'superhot' component

Science.gov (United States)

Nitta, Nariaki

1988-01-01

Hard X-ray spectra in solar flares obtained by the broadband spectrometers aboard Hinotori and SMM are compared. Within the uncertainty brought about by assuming the typical energy of the background X-rays, spectra by the Hinotori spectrometer are usually consistent with those by the SMM spectrometer for flares in 1981. On the contrary, flares in 1982 persistently show 20-50-percent higher flux by Hinotori than by SMM. If this discrepancy is entirely attributable to errors in the calibration of energy ranges, the errors would be about 10 percent. Despite such a discrepancy in absolute flux, in the the decay phase of one flare, spectra revealed a hard X-ray component (probably a 'superhot' component) that could be explained neither by emission from a plasma at about 2 x 10 to the 7th K nor by a nonthermal power-law component. Imaging observations during this period show hard X-ray emission nearly cospatial with soft X-ray emission, in contrast with earlier times at which hard and soft X-rays come from different places.

Future X-ray Polarimetry of Relativistic Accelerators: Pulsar Wind Nebulae and Supernova Remnants

Directory of Open Access Journals (Sweden)

Niccolò Bucciantini

2018-03-01

Full Text Available Supernova remnants (SNRs and pulsar wind nebulae (PWNs are among the most significant sources of non-thermal X-rays in the sky, and the best means by which relativistic plasma dynamics and particle acceleration can be investigated. Being strong synchrotron emitters, they are ideal candidates for X-ray polarimetry, and indeed the Crab nebula is up to present the only object where X-ray polarization has been detected with a high level of significance. Future polarimetric measures will likely provide us with crucial information on the level of turbulence that is expected at particle acceleration sites, together with the spatial and temporal coherence of magnetic field geometry, enabling us to set stronger constraints on our acceleration models. PWNs will also allow us to estimate the level of internal dissipation. I will briefly review the current knowledge on the polarization signatures in SNRs and PWNs, and I will illustrate what we can hope to achieve with future missions such as IXPE/XIPE.

Nonthermal emission from clusters of galaxies

Energy Technology Data Exchange (ETDEWEB)

Kushnir, Doron; Waxman, Eli, E-mail: doron.kushnir@weizmann.ac.il, E-mail: eli.waxman@weizmann.ac.il [Physics Faculty, Weizmann Institute of Science, PO Box 26, Rehovot (Israel)

2009-08-01

We show that the spectral and radial distribution of the nonthermal emission of massive, M ∼> 10{sup 14.5}M{sub ☉}, galaxy clusters may be approximately described by simple analytic expressions, which depend on the cluster thermal X-ray properties and on two model parameter, β{sub core} and η{sub e}. β{sub core} is the ratio of the cosmic-ray (CR) energy density (within a logarithmic CR energy interval) and the thermal energy density at the cluster core, and η{sub e(p)} is the fraction of the thermal energy generated in strong collisionless shocks, which is deposited in CR electrons (protons). Using a simple analytic model for the evolution of intra-cluster medium CRs, which are produced by accretion shocks, we find that β{sub core} ≅ η{sub p}/200, nearly independent of cluster mass and with a scatter Δln β{sub core} ≅ 1 between clusters of given mass. We show that the hard X-ray (HXR) and γ-ray luminosities produced by inverse Compton scattering of CMB photons by electrons accelerated in accretion shocks (primary electrons) exceed the luminosities produced by secondary particles (generated in hadronic interactions within the cluster) by factors ≅ 500(η{sub e}/η{sub p})(T/10 keV){sup −1/2} and ≅ 150(η{sub e}/η{sub p})(T/10 keV){sup −1/2} respectively, where T is the cluster temperature. Secondary particle emission may dominate at the radio and very high energy (∼> 1 TeV) γ-ray bands. Our model predicts, in contrast with some earlier work, that the HXR and γ-ray emission from clusters of galaxies are extended, since the emission is dominated at these energies by primary (rather than by secondary) electrons. Our predictions are consistent with the observed nonthermal emission of the Coma cluster for η{sub p} ∼ η{sub e} ∼ 0.1. The implications of our predictions to future HXR observations (e.g. by NuStar, Simbol-X) and to (space/ground based) γ-ray observations (e.g. by Fermi, HESS, MAGIC, VERITAS) are discussed. In particular

X-ray flares from runaway pair production in active galactic nuclei

Science.gov (United States)

Kirk, J. G.; Mastichiadis, A.

1992-01-01

The hard X-ray spectrum of AGNs is nonthermal, probably arising from an electron-positron pair cascade, with some emission reflected off relatively cold matter. There has been interest in models on which protons are accelerated and create relativistic electrons on interaction with a local radiation field. It is shown here that a sufficient column density of protons can lead to runaway pair production: photons generated by the relativistic pairs are the targets for the protons to produce more pairs. This can produce X-ray fluxes with the characteristics observed in AGN. The model predicts the maximum ratio of luminosity to source size as well as their spectrum in the early phases. The same mechanism may also be able to create the knots of synchrotron-radiating pair plasma seen in sources such as 3C273.

Characteristics of x-rays from a plasma focus operated with neon gas

Energy Technology Data Exchange (ETDEWEB)

Zakaullah, M [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Alamgir, K [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Shafiq, M [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Hassan, S M [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Sharif, M [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Hussain, S [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Waheed, A [PINSTECH, PO Box 2151, 44000 Islamabad (Pakistan)

2002-11-01

The x-ray emission from a low-energy (2.3 kJ) plasma focus is investigated with neon as the filling gas. Two anode configurations are used in the experiment: the conventional cylindrical anode, and tapered anode slightly toward the open end. The latter geometry enhances soft x-ray emission by an order of magnitude. The emission is pressure dependent and, in both cases, the highest emission is observed at 3-3.5 mbar. For the cylindrical anode, the soft x-ray emission is up to 7 J per shot, which is from a pinched plasma column, 5-6 mm long. For the tapered anode, up to 80 J per shot soft x-ray yield in 4{pi} geometry is recorded, which corresponds to 4% wall plug efficiency. The diameter of the x-ray emission filament is much larger compared with the cylindrical anode. The bulk of emitted radiation is of energy 1.2-1.3 keV, which is thought to arise from recombination of hydrogen-like (Ne x) ions with the low-energy electrons.

Characteristics of x-rays from a plasma focus operated with neon gas

International Nuclear Information System (INIS)

Zakaullah, M; Alamgir, K; Shafiq, M; Hassan, S M; Sharif, M; Hussain, S; Waheed, A

2002-01-01

The x-ray emission from a low-energy (2.3 kJ) plasma focus is investigated with neon as the filling gas. Two anode configurations are used in the experiment: the conventional cylindrical anode, and tapered anode slightly toward the open end. The latter geometry enhances soft x-ray emission by an order of magnitude. The emission is pressure dependent and, in both cases, the highest emission is observed at 3-3.5 mbar. For the cylindrical anode, the soft x-ray emission is up to 7 J per shot, which is from a pinched plasma column, 5-6 mm long. For the tapered anode, up to 80 J per shot soft x-ray yield in 4π geometry is recorded, which corresponds to 4% wall plug efficiency. The diameter of the x-ray emission filament is much larger compared with the cylindrical anode. The bulk of emitted radiation is of energy 1.2-1.3 keV, which is thought to arise from recombination of hydrogen-like (Ne x) ions with the low-energy electrons

X-RAY EMISSION FROM SN 2004dj: A TALE OF TWO SHOCKS

Energy Technology Data Exchange (ETDEWEB)

Chakraborti, Sayan; Yadav, Naveen; Ray, Alak [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Colaba, Mumbai 400 005 (India); Smith, Randall [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Chandra, Poonam [Department of Physics, Royal Military College of Canada, Kingston, ON K7K 7B4 (Canada); Pooley, David, E-mail: schakraborti@fas.harvard.edu [Department of Physics, Sam Houston State University, Huntsville, TX (United States)

2012-12-20

Type IIP (Plateau) supernovae are the most commonly observed variety of core-collapse events. They have been detected in a wide range of wavelengths from radio, through optical to X-rays. The standard picture of a Type IIP supernova has the blastwave interacting with the progenitor's circumstellar matter to produce a hot region bounded by a forward and a reverse shock. This region is thought to be responsible for most of the X-ray and radio emission from these objects. Yet the origin of X-rays from these supernovae is not well understood quantitatively. The relative contributions of particle acceleration and magnetic field amplification in generating the X-ray and radio emission need to be determined. In this work, we analyze archival Chandra observations of SN 2004dj, one of the nearest supernovae since SN 1987A, along with published radio and optical information. We determine the pre-explosion mass-loss rate, blastwave velocity, electron acceleration, and magnetic field amplification efficiencies. We find that a greater fraction of the thermal energy goes into accelerating electrons than into amplifying magnetic fields. We conclude that the X-ray emission arises out of a combination of inverse Compton scattering by non-thermal electrons accelerated in the forward shock and thermal emission from supernova ejecta heated by the reverse shock.

The Relationship Between Solar Radio and Hard X-Ray Emission

Science.gov (United States)

White, S. M.; Benz, A. O.; Christe, S.; Farnik, F.; Kundu, M. R.; Mann, G.; Ning, Z.; Raulin, J.-P.; Silva-Valio, A. V. R.; Saint-Hilaire, P.;

A filament of dark matter between two clusters of galaxies.

Science.gov (United States)

Dietrich, Jörg P; Werner, Norbert; Clowe, Douglas; Finoguenov, Alexis; Kitching, Tom; Miller, Lance; Simionescu, Aurora

2012-07-12

It is a firm prediction of the concordance cold-dark-matter cosmological model that galaxy clusters occur at the intersection of large-scale structure filaments. The thread-like structure of this 'cosmic web' has been traced by galaxy redshift surveys for decades. More recently, the warm–hot intergalactic medium (a sparse plasma with temperatures of 10(5) kelvin to 10(7) kelvin) residing in low-redshift filaments has been observed in emission and absorption. However, a reliable direct detection of the underlying dark-matter skeleton, which should contain more than half of all matter, has remained elusive, because earlier candidates for such detections were either falsified or suffered from low signal-to-noise ratios and unphysical misalignments of dark and luminous matter. Here we report the detection of a dark-matter filament connecting the two main components of the Abell 222/223 supercluster system from its weak gravitational lensing signal, both in a non-parametric mass reconstruction and in parametric model fits. This filament is coincident with an overdensity of galaxies and diffuse, soft-X-ray emission, and contributes a mass comparable to that of an additional galaxy cluster to the total mass of the supercluster. By combining this result with X-ray observations, we can place an upper limit of 0.09 on the hot gas fraction (the mass of X-ray-emitting gas divided by the total mass) in the filament.

Non-thermal Processes in Colliding-wind Massive Binaries: the Contribution of Simbol-X to a Multiwavelength Investigation

Science.gov (United States)

De Becker, Michaël; Blomme, Ronny; Micela, Giusi; Pittard, Julian M.; Rauw, Gregor; Romero, Gustavo E.; Sana, Hugues; Stevens, Ian R.

2009-05-01

Several colliding-wind massive binaries are known to be non-thermal emitters in the radio domain. This constitutes strong evidence for the fact that an efficient particle acceleration process is at work in these objects. The acceleration mechanism is most probably the Diffusive Shock Acceleration (DSA) process in the presence of strong hydrodynamic shocks due to the colliding-winds. In order to investigate the physics of this particle acceleration, we initiated a multiwavelength campaign covering a large part of the electromagnetic spectrum. In this context, the detailed study of the hard X-ray emission from these sources in the SIMBOL-X bandpass constitutes a crucial element in order to probe this still poorly known topic of astrophysics. It should be noted that colliding-wind massive binaries should be considered as very valuable targets for the investigation of particle acceleration in a similar way as supernova remnants, but in a different region of the parameter space.

Exploring Hot Gas at Junctions of Galaxy Filaments

Science.gov (United States)

Mitsuishi, Ikuyuki; Yamasaki, Noriko; Kawahara, Hajime; Sekiya, Norio; Sasaki, Shin; Sousbie, Thierry

Because galaxies are forced to follow the strong gravitational potential created by the underlying cosmic web of the dark matter, their distribution reflects its filamentary structures. By identifying the filamentary structures, one can therefore recover a map of the network that drives structure formation. Filamentary junctions are regions of particular interest as they identify places where mergers and other interesting astrophysical phenomena have high chances to occur. We identified the galaxy filaments by our original method (Sousbie (2011) & Sousbie et al. (2011)) and X-ray pointing observations were conducted for the six fields locating in the junctions of the galaxy filaments where no specific diffuse X-ray emissions had previously been detected so far. We discovered significant X-ray signals in their images and spectra of the all regions. Spectral analysis demonstrated that six sources originate from diffuse emissions associated with optically bright galaxies, group-scale, or cluster-scale X-ray halos with kT˜1-4 keV, while the others are compact object origin. Interestingly, all of the newly discovered three intracluster media show peculiar features such as complex or elongated morphologies in X-ray and/or optical and hot spot involved in ongoing merger events (Kawahara et al. (2011) & Mitsuishi et al. (2014)). In this conference, results of follow-up radio observations for the merging groups as well as the details of the X-ray observations will be reported.

Constancy of radiation output during diagnostic X-ray exposures

International Nuclear Information System (INIS)

Ardran, G.M.; Crooks, H.E.; Birch, R.

1978-01-01

Variation in X-ray output and quality during a diagnostic exposure can be undesirable and may result in unnecessary dose to the patient. When significant build-up or decay periods are present errors will arise if factors obtained under steady-state conditions are employed to estimate the exposure. These parameters must be taken into account when calibrating X-ray generators. A variable speed spinning film device and a spectrometry system have been used to measure the variations under fluoroscopic and radiographic conditions for a number of generators. Variations in output due to filament heating, voltage supply and rectification, cable capacity and target pitting have been demonstrated. At low fluoroscopic currents, large surges and long decays have been observed; the significance of these effects is considered. (author)

Non-thermal electron populations in microwave heated plasmas investigated with X-ray detectors

Energy Technology Data Exchange (ETDEWEB)

Belapure, Jaydeep Sanjay

2013-04-15

An investigation of the generation and dynamics of superthermal electrons in fusion plasma is carried out. A SDD+CsI(Tl) based X-ray diagnostic is constructed, characterized and installed at ASDEX Upgrade. In various plasma heating power and densities, the fraction and the energy distribution of the superthermal electrons is obtained by a bi-Maxwellian model and compared with Fokker-Planck simulations.

Advanced imaging technology using carbon nanotube x ray source

International Nuclear Information System (INIS)

Choi, Hae Young; Seol, Seung Kown; Kim, Jaehoon; Yoo, Seung Hoon; Kim, Jong Uk

2008-01-01

Recently, X ray imaging technology is a useful and leading medical diagnostic tool for healthcare professionals to diagnose disease in human body. CNTs(i.e. carbon nanotubes)are used in many applications like FED, Micro wave amplifier, X ray source, etc. because of its suitable electrical, chemical and physical properties. Specially, CNTs are well used electron emitters for x ray source. Conventionally, thermionic type of tungsten filament x ray tube is widely employed in the field of bio medical and industrial application fields. However, intrinsic problems such as, poor emission efficiency and low imaging resolution cause the limitation of use of the x ray tube. To fulfill the current market requirement specifically for medical diagnostic field, we have developed rather a portable and compact CNT based x ray source in which high imaging resolution is provided. Electron sources used in X ray tubes should be well focused to the anode target for generation of high quality x ray. In this study, Pierce type x ray generation module was tested based its simulation results using by OPERA 3D code. Pierce type module is composed of cone type electrical lens with its number of them and inner angles of them that shows different results with these parameters. And some preliminary images obtained using the CNT x ray source were obtained. The represented images are the finger bone and teeth in human body. It is clear that the trabeculation shape is observed in finger bone. To obtain the finger bone image, tube currents of 250A at 42kV tube voltage was applied. The human tooth image, however, is somewhat unclear because the supplied voltage to the tube was limited to max. 50kV in the system developed. It should be noted that normally 60∼70kV of tube voltage is supplied in dental imaging. Considering these it should be emphasized that if the tube voltage is over 60kV then clearer image is possible. In this paper, we are discussed comparing between these experiment results and

Polarization and spectral features of the hard x-ray continuum from non-thermal plasmas

International Nuclear Information System (INIS)

Hesse, M.; Platz, P.

1989-12-01

Starting from the cross-sections for the free-free radiation obtained within the relativistic Born-Elwert theory, we calculate the spectral and polarization properties of the hard X-ray continuum (hν > 50 KeV) for plasmas containing fast electrons with an anisotropic velocity distribution. The physical and geometrical quantities of our model are oriented towards the future lower-hybrid current drive (LHCD) experiments on Tore-Supra. Our parameter space covers parallel and perpendicular temperatures, the nuclear charge of the ions (mainly Z = 14 and 28), the cut-off energy of the electrons, the radial current profile and the viewing angle. Extensive calculations open on the optimum conditions for polarization measurements and also give guide-lines for the quantitative interpretation of data under real plasma conditions. A second part of this report will treat with the operational principles and expected performances of hard X-ray polarimeters

Development of multi-pixel x-ray source using oxide-coated cathodes.

Science.gov (United States)

Kandlakunta, Praneeth; Pham, Richard; Khan, Rao; Zhang, Tiezhi

2017-07-07

Multiple pixel x-ray sources facilitate new designs of imaging modalities that may result in faster imaging speed, improved image quality, and more compact geometry. We are developing a high-brightness multiple-pixel thermionic emission x-ray (MPTEX) source based on oxide-coated cathodes. Oxide cathodes have high emission efficiency and, thereby, produce high emission current density at low temperature when compared to traditional tungsten filaments. Indirectly heated micro-rectangular oxide cathodes were developed using carbonates, which were converted to semiconductor oxides of barium, strontium, and calcium after activation. Each cathode produces a focal spot on an elongated fixed anode. The x-ray beam ON and OFF control is performed by source-switching electronics, which supplies bias voltage to the cathode emitters. In this paper, we report the initial performance of the oxide-coated cathodes and the MPTEX source.

Field induced decrystallization of silicon: Evidence of a microwave non-thermal effect

Science.gov (United States)

Nozariasbmarz, Amin; Dsouza, Kelvin; Vashaee, Daryoosh

2018-02-01

It is rather strange and not fully understood that some materials decrystallize when exposed to microwave radiation, and it is still debatable if such a transformation is a thermal or non-thermal effect. We hereby report experimental evidences that weight the latter effect. First, a single crystal silicon wafer exposed to microwaves showed strong decrystallization at high temperature. Second, when some areas of the wafer were masked with metal coating, only the exposed areas underwent decrystallization. Transmission electron microscopy analysis, x-ray diffraction data, and thermal conductivity measurements all indicated strong decrystallization, which occurred in the bulk of the material and was not a surface effect. These observations favor the existence of a non-thermal microwave effect.

X-ray filter for x-ray powder diffraction

Science.gov (United States)

Sinsheimer, John Jay; Conley, Raymond P.; Bouet, Nathalie C. D.; Dooryhee, Eric; Ghose, Sanjit

2018-01-23

Technologies are described for apparatus, methods and systems effective for filtering. The filters may comprise a first plate. The first plate may include an x-ray absorbing material and walls defining first slits. The first slits may include arc shaped openings through the first plate. The walls of the first plate may be configured to absorb at least some of first x-rays when the first x-rays are incident on the x-ray absorbing material, and to output second x-rays. The filters may comprise a second plate spaced from the first plate. The second plate may include the x-ray absorbing material and walls defining second slits. The second slits may include arc shaped openings through the second plate. The walls of the second plate may be configured to absorb at least some of second x-rays and to output third x-rays.

Developments in hot-filament metal oxide deposition (HFMOD)

International Nuclear Information System (INIS)

Durrant, Steven F.; Trasferetti, Benedito C.; Scarminio, Jair; Davanzo, Celso U.; Rouxinol, Francisco P.M.; Gelamo, Rogerio V.; Bica de Moraes, Mario A.

2008-01-01

Hot-filament metal oxide deposition (HFMOD) is a variant of conventional hot-filament chemical vapor deposition (HFCVD) recently developed in our laboratory and successfully used to obtain high-quality, uniform films of MO x , WO x and VO x . The method employs the controlled oxidation of a filament of a transition metal heated to 1000 deg. C or more in a rarefied oxygen atmosphere (typically, of about 1 Pa). Metal oxide vapor formed on the surface of the filament is transported a few centimetres to deposit on a suitable substrate. Key system parameters include the choice of filament material and diameter, the applied current and the partial pressures of oxygen in the chamber. Relatively high film deposition rates, such as 31 nm min -1 for MoO x , are obtained. The film stoichiometry depends on the exact deposition conditions. MoO x films, for example, present a mixture of MoO 2 and MoO 3 phases, as revealed by XPS. As determined by Li + intercalation using an electrochemical cell, these films also show a colouration efficiency of 19.5 cm 2 C -1 at a wavelength of 700 nm. MO x and WO x films are promising in applications involving electrochromism and characteristics of their colouring/bleaching cycles are presented. The chemical composition and structure of VO x films examined using IRRAS (infrared reflection-absorption spectroscopy), RBS (Rutherford backscattering spectrometry) and XPS (X-ray photoelectron spectrometry) are also presented

X-ray fluorescence imaging with polycapillary X-ray optics

International Nuclear Information System (INIS)

Yonehara, Tasuku; Yamaguchi, Makoto; Tsuji, Kouichi

2010-01-01

X-ray fluorescence spectrometry imaging is a powerful tool to provide information about the chemical composition and elemental distribution of a specimen. X-ray fluorescence spectrometry images were conventionally obtained by using a μ-X-ray fluorescence spectrometry spectrometer, which requires scanning a sample. Faster X-ray fluorescence spectrometry imaging would be achieved by eliminating the process of sample scanning. Thus, we developed an X-ray fluorescence spectrometry imaging instrument without sample scanning by using polycapillary X-ray optics, which had energy filter characteristics caused by the energy dependence of the total reflection phenomenon. In the present paper, we show that two independent straight polycapillary X-ray optics could be used as an energy filter of X-rays for X-ray fluorescence. Only low energy X-rays were detected when the angle between the two optical axes was increased slightly. Energy-selective X-ray fluorescence spectrometry images with projection mode were taken by using an X-ray CCD camera equipped with two polycapillary optics. It was shown that Fe Kα (6.40 keV) and Cu Kα (8.04 keV) could be discriminated for Fe and Cu foils.

Characterization of feed channel spacer performance using geometries obtained by X-ray computed tomography

KAUST Repository

Haaksman, Viktor A.; Siddiqui, Amber; Schellenberg, Carsten; Kidwell, James; Vrouwenvelder, Johannes S.; Picioreanu, Cristian

2016-01-01

design from X-ray computed tomography (CT) scans. The method revealed that the filaments of industrial spacers have a highly variable cross-section size and shape, which impact the flow characteristics in the feed channel. The pressure drop and friction

X-ray emitting hot plasma in solar active regions observed by the SphinX spectrometer

Science.gov (United States)

Miceli, M.; Reale, F.; Gburek, S.; Terzo, S.; Barbera, M.; Collura, A.; Sylwester, J.; Kowalinski, M.; Podgorski, P.; Gryciuk, M.

2012-08-01

Aims: The detection of very hot plasma in the quiescent corona is important for diagnosing heating mechanisms. The presence and the amount of such hot plasma is currently debated. The SphinX instrument on-board the CORONAS-PHOTON mission is sensitive to X-ray emission of energies well above 1 keV and provides the opportunity to detect the hot plasma component. Methods: We analysed the X-ray spectra of the solar corona collected by the SphinX spectrometer in May 2009 (when two active regions were present). We modelled the spectrum extracted from the whole Sun over a time window of 17 days in the 1.34-7 keV energy band by adopting the latest release of the APED database. Results: The SphinX broadband spectrum cannot be modelled by a single isothermal component of optically thin plasma and two components are necessary. In particular, the high statistical significance of the count rates and the accurate calibration of the spectrometer allowed us to detect a very hot component at ~7 million K with an emission measure of ~2.7 × 1044 cm-3. The X-ray emission from the hot plasma dominates the solar X-ray spectrum above 4 keV. We checked that this hot component is invariably present in both the high and low emission regimes, i.e. even excluding resolvable microflares. We also present and discuss the possibility of a non-thermal origin (which would be compatible with a weak contribution from thick-target bremsstrahlung) for this hard emission component. Conclusions: Our results support the nanoflare scenario and might confirm that a minor flaring activity is ever-present in the quiescent corona, as also inferred for the coronae of other stars.

Energetic electron propagation in the decay phase of non-thermal flare emission

Energy Technology Data Exchange (ETDEWEB)

Huang, Jing; Yan, Yihua [Key Laboratory of Solar Activities, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Tsap, Yuri T., E-mail: huangj@nao.cas.cn [Crimean Astrophysical Observatory of Kyiv National Taras Shevchenko University, 98409 Crimea, Nauchny (Ukraine)

2014-06-01

On the basis of the trap-plus-precipitation model, the peculiarities of non-thermal emission in the decay phase of solar flares have been considered. The calculation formulas for the escape rate of trapped electrons into the loss cone in terms of time profiles of hard X-ray (HXR) and microwave (MW) emission have been obtained. It has been found that the evolution of the spectral indices of non-thermal emission depend on the regimes of the pitch angle diffusion of trapped particles into the loss cone. The properties of non-thermal electrons related to the HXR and MW emission of the solar flare on 2004 November 3 are studied with Nobeyama Radioheliograph, Nobeyama Radio Polarimeters, RHESSI, and Geostationary Operational Environmental Satellite observations. The spectral indices of non-thermal electrons related to MW and HXR emission remained constant or decreased, while the MW escape rate as distinguished from that of the HXRs increased. This may be associated with different diffusion regimes of trapped electrons into the loss cone. New arguments in favor of an important role of the superstrong diffusion for high-energy electrons in flare coronal loops have been obtained.

Direct observation of conductive filament formation in Alq3 based organic resistive memories

Energy Technology Data Exchange (ETDEWEB)

Busby, Y., E-mail: yan.busby@unamur.be; Pireaux, J.-J. [Research Center in the Physics of Matter and Radiation (PMR), Laboratoire Interdisciplinaire de Spectroscopie Electronique (LISE), University of Namur, B-5000 Namur (Belgium); Nau, S.; Sax, S. [NanoTecCenter Weiz Forschungsgesellschaft mbH, Franz-Pichler Straße 32, A-8160 Weiz (Austria); List-Kratochvil, E. J. W. [NanoTecCenter Weiz Forschungsgesellschaft mbH, Franz-Pichler Straße 32, A-8160 Weiz (Austria); Institute of Solid State Physics, Graz University of Technology, A-8010 Graz (Austria); Novak, J.; Banerjee, R.; Schreiber, F. [Institute of Applied Physics, Eberhard-Karls-Universität Tübingen, D-72076 Tübingen (Germany)

2015-08-21

This work explores resistive switching mechanisms in non-volatile organic memory devices based on tris(8-hydroxyquinolie)aluminum (Alq{sub 3}). Advanced characterization tools are applied to investigate metal diffusion in ITO/Alq{sub 3}/Ag memory device stacks leading to conductive filament formation. The morphology of Alq{sub 3}/Ag layers as a function of the metal evaporation conditions is studied by X-ray reflectivity, while depth profile analysis with X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry is applied to characterize operational memory elements displaying reliable bistable current-voltage characteristics. 3D images of the distribution of silver inside the organic layer clearly point towards the existence of conductive filaments and allow for the identification of the initial filament formation and inactivation mechanisms during switching of the device. Initial filament formation is suggested to be driven by field assisted diffusion of silver from abundant structures formed during the top electrode evaporation, whereas thermochemical effects lead to local filament inactivation.

X-Ray Absorption with Transmission X-Ray Microscopes

NARCIS (Netherlands)

de Groot, F.M.F.

2016-01-01

In this section we focus on the use of transmission X-ray microscopy (TXM) to measure the XAS spectra. In the last decade a range of soft X-ray and hard X-ray TXM microscopes have been developed, allowing the measurement of XAS spectra with 10–100 nm resolution. In the hard X-ray range the TXM

Suzaku observations of the outskirts of the galaxy cluster Abell 3395, including a filament toward Abell 3391

Science.gov (United States)

Sugawara, Yuuki; Takizawa, Motokazu; Itahana, Madoka; Akamatsu, Hiroki; Fujita, Yutaka; Ohashi, Takaya; Ishisaki, Yoshitaka

2017-12-01

The results of Suzaku observations of the outskirts of Abell 3395, including a large-scale structure filament toward Abell 3391, are presented. We measured temperature and abundance distributions from the southern outskirt of A 3395 to the north at the virial radius, where a filament structure has been found in the former X-ray and Sunyaev-Zel'dovich (SZ) effect observations between A 3391 and A 3395. The overall temperature structure is consistent with the universal profile proposed by Okabe, N., et al. 2014, PASJ, 66, 99 for relaxed clusters, except for the filament region. A hint of intracluster medium heating is found between the two clusters, which might be due to their interaction in the early phase of a cluster merger. Although we obtained a relatively low metal abundance of Z=0.169^{+0.164+0.009+0.018}_{-0.150-0.004-0.015} solar, where the first, second, and third errors are statistical, cosmic X-ray background systematic, and non-X-ray background systematic, respectively, at the virial radius in the filament, our results are still consistent with previous results for other clusters (Z ˜ 0.3 solar) within errors. Therefore, our results are also consistent with the early enrichment scenario. We estimated Compton y parameters only from X-ray results in the region between A 3391 and A 3395 assuming a simple geometry. They are smaller than the previous SZ results with the Planck satellite. The difference could be attributed to a more elaborate geometry such as a filament inclined to the line-of-sight direction, or underestimation of the X-ray temperature because of the unresolved multi-temperature structures or undetected hot X-ray emission of the shock-heated gas.

RADIO AND X-RAY OBSERVATIONS OF SN 2006jd: ANOTHER STRONGLY INTERACTING TYPE IIn SUPERNOVA

Energy Technology Data Exchange (ETDEWEB)

Chandra, Poonam [Department of Physics, Royal Military College of Canada, Kingston, ON K7K 7B4 (Canada); Chevalier, Roger A.; Irwin, Christopher M. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Chugai, Nikolai [Institute of Astronomy of Russian Academy of Sciences, Pyatnitskaya Street 48, 109017 Moscow (Russian Federation); Fransson, Claes [Department of Astronomy, Stockholm University, AlbaNova, SE-106 91 Stockholm (Sweden); Soderberg, Alicia M. [Smithsonian Astrophysical Observatory, 60 Garden Street, MS-20, Cambridge, MA 02138 (United States); Chakraborti, Sayan [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Colaba, Mumbai 400005 (India); Immler, Stefan, E-mail: Poonam.Chandra@rmc.ca [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2012-08-20

We report four years of radio and X-ray monitoring of the Type IIn supernova SN 2006jd at radio wavelengths with the Very Large Array, Giant Metrewave Radio Telescope, and Expanded Very Large Array; at X-ray wavelengths with Chandra, XMM-Newton, and Swift-XRT. We assume that the radio and X-ray emitting particles are produced by shock interaction with a dense circumstellar medium. The radio emission shows an initial rise that can be attributed to free-free absorption by cool gas mixed into the nonthermal emitting region; external free-free absorption is disfavored because of the shape of the rising light curves and the low gas column density inferred along the line of sight to the emission region. The X-ray luminosity implies a preshock circumstellar density {approx}10{sup 6} cm{sup -3} at a radius r {approx} 2 Multiplication-Sign 10{sup 16} cm, but the column density inferred from the photoabsorption of X-rays along the line of sight suggests a significantly lower density. The implication may be an asymmetry in the interaction. The X-ray spectrum shows Fe line emission at 6.9 keV that is stronger than is expected for the conditions in the X-ray emitting gas. We suggest that cool gas mixed into the hot gas plays a role in the line emission. Our radio and X-ray data both suggest the density profile is flatter than r{sup -2} because of the slow evolution of the unabsorbed emission.

Combined synthetic x-ray and radio observations of simulated radio jets

Energy Technology Data Exchange (ETDEWEB)

Tregillis, I. L. (Ian L.); Jones, T. W. (Thomas Walter),; Ryu, Dongsu

2004-01-01

We present results from an extensive synthetic observation analysis of numerically-simulated radio galaxy jets. This is the first such analysis to be based on simulations with sufficient physical detail to allow the application of standard observational analysis techniques to simulated radio galaxies. Here we focus on extracting magnetic field properties from nonthermal intensity information. We study field values obtained via the combination of synchrotron radio and inverse-Compton X-ray data as well as those from the minimum-energy approach. The combined radio/X-ray technique provides meaningful information about the field. The minimum-energy approach retrieves reasonable field estimates in regions physically close to the minimum-energy partitioning, though the technique is highly susceptible to deviations from the underlying assumptions. We also look at how the two field measurement techniques might be combined to provide a rough measure of the actual energy in particles and fields. A full report on this work can be found in the Astrophysical Journal, v601, p778.

Developments in hot-filament metal oxide deposition (HFMOD)

Energy Technology Data Exchange (ETDEWEB)

Durrant, Steven F. [Laboratorio de Plasmas Tecnologicos, Campus Experimental de Sorocaba, Universidade Estadual Paulista (UNESP), Avenida Tres de Marco, 511, Alto de Boa Vista, 18087-180 Sorocaba, SP (Brazil)], E-mail: steve@sorocaba.unesp.br; Trasferetti, Benedito C. [Departamento de Policia Federal, Superintendencia Regional no Piaui, Setor Tecnico-Cientifico, Avenida Maranhao, 1022/N, 64.000-010, Teresina, PI (Brazil); Scarminio, Jair [Departamento de Fisica, Universidade Estadual de Londrina (UEL), 86051-990, Londrina, PR (Brazil); Davanzo, Celso U. [Instituto de Quimica, Universidade Estadual de Campinas (UNICAMP), 13083-970, Campinas, SP (Brazil); Rouxinol, Francisco P.M.; Gelamo, Rogerio V.; Bica de Moraes, Mario A. [Laboratorio de Processos de Plasma, Departamento de Fisica Aplicada, Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas (UNICAMP), 13083-970, Campinas, SP (Brazil)

2008-01-15

Hot-filament metal oxide deposition (HFMOD) is a variant of conventional hot-filament chemical vapor deposition (HFCVD) recently developed in our laboratory and successfully used to obtain high-quality, uniform films of MO{sub x}, WO{sub x} and VO{sub x}. The method employs the controlled oxidation of a filament of a transition metal heated to 1000 deg. C or more in a rarefied oxygen atmosphere (typically, of about 1 Pa). Metal oxide vapor formed on the surface of the filament is transported a few centimetres to deposit on a suitable substrate. Key system parameters include the choice of filament material and diameter, the applied current and the partial pressures of oxygen in the chamber. Relatively high film deposition rates, such as 31 nm min{sup -1} for MoO{sub x}, are obtained. The film stoichiometry depends on the exact deposition conditions. MoO{sub x} films, for example, present a mixture of MoO{sub 2} and MoO{sub 3} phases, as revealed by XPS. As determined by Li{sup +} intercalation using an electrochemical cell, these films also show a colouration efficiency of 19.5 cm{sup 2} C{sup -1} at a wavelength of 700 nm. MO{sub x} and WO{sub x} films are promising in applications involving electrochromism and characteristics of their colouring/bleaching cycles are presented. The chemical composition and structure of VO{sub x} films examined using IRRAS (infrared reflection-absorption spectroscopy), RBS (Rutherford backscattering spectrometry) and XPS (X-ray photoelectron spectrometry) are also presented.

THE ROLE OF KELVIN–HELMHOLTZ INSTABILITY FOR PRODUCING LOOP-TOP HARD X-RAY SOURCES IN SOLAR FLARES

Energy Technology Data Exchange (ETDEWEB)

Fang, Xia; Yuan, Ding; Xia, Chun; Doorsselaere, Tom Van; Keppens, Rony [Centre for Mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, 3001 Leuven (Belgium)

2016-12-10

We propose a model for the formation of loop-top hard X-ray (HXR) sources in solar flares through the inverse Compton mechanism, scattering the surrounding soft X-ray (SXR) photons to higher energy HXR photons. We simulate the consequences of a flare-driven energy deposit in the upper chromosphere in the impulsive phase of single loop flares. The consequent chromosphere evaporation flows from both footpoints reach speeds up to hundreds of kilometers per second, and we demonstrate how this triggers Kelvin–Helmholtz instability (KHI) in the loop top, under mildly asymmetric conditions, or more toward the loop flank for strongly asymmetric cases. The KHI vortices further fragment the magnetic topology into multiple magnetic islands and current sheets, and the hot plasma within leads to a bright loop-top SXR source region. We argue that the magnetohydrodynamic turbulence that appears at the loop apex could be an efficient accelerator of non-thermal particles, which the island structures can trap at the loop-top. These accelerated non-thermal particles can upscatter the surrounding thermal SXR photons emitted by the extremely hot evaporated plasma to HXR photons.

STROBE-X: X-ray Timing & Spectroscopy on Dynamical Timescales from Microseconds to Years

Science.gov (United States)

Wilson-Hodge, Colleen A.; Ray, Paul S.; Maccarone, Thomas J.; Chakrabarty, Deepto; Gendreau, Keith C.; Arzoumanian, Zaven; Jenke, Peter; Ballantyne, David; Bozzo, Enrico; Brandt, Soren; Brenneman, Laura; Christophersen, Marc; DeRosa, Alessandra; Feroci, Marco; Goldstein, Adam; Hartmann, Dieter; Hernanz, Margarita; McDonald, Michael; Phlips, Bernard; Remillard, Ronald; Stevens, Abigail; Tomsick, John; Watts, Anna; Wood, Kent S.; Zane, Silvia; STROBE-X Collaboration

2018-01-01

We describe a probe-class mission concept that provides an unprecedented view of the X-ray sky, performing timing and 0.2-30 keV spectroscopy over timescales from microseconds to years. The Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X) comprises three primary instruments. The first uses an array of lightweight optics (3-m focal length) that concentrate incident photons onto solid state detectors with CCD-level (85-130 eV) energy resolution, 100 ns time resolution, and low background rates to cover the 0.2-12 keV band. This technology is scaled up from NICER, with enhanced optics to take advantage of the longer focal length of STROBE-X. The second uses large-area collimated silicon drift detectors, developed for ESA's LOFT, to cover the 2-30 keV band. These two instruments each provide an order of magnitude improvement in effective area compared with its predecessor (NICER and RXTE, respectively). Finally, a sensitive sky monitor triggers pointed observations, provides high duty cycle, high time resolution, high spectral resolution monitoring of the X-ray sky with ~20 times the sensitivity of the RXTE ASM, and enables multi-wavelength and multi-messenger studies on a continuous, rather than scanning basis. We include updated instrument designs resulting from the GSFC IDL run in November 2017.For the first time, the broad coverage provides simultaneous study of thermal components, non-thermal components, iron lines, and reflection features from a single platform for accreting black holes at all scales. The enormous collecting area allows detailed studies of the dense matter equation of state using both thermal emission from rotation-powered pulsars and harder emission from X-ray burst oscillations. The combination of the wide-field monitor and the sensitive pointed instruments enables observations of potential electromagnetic counterparts to LIGO/Virgo and neutrino events. Extragalactic science, such as constraining bulk metalicity

STROBE-X: X-ray Timing & Spectroscopy on Dynamical Timescales from Milliseconds to Years

Science.gov (United States)

Wilson-Hodge, Colleen A.; Ray, P. S.; Maccarone, T; Chakrabarty, D.; Gendreau, K.; Arzoumanian, Z.; Jenke, P.; Ballantyne, D.; Bozzo, E.; Brandt, S.;

Influence of Xe and Kr impurities on x-ray yield from debris-free plasma x-ray sources with an Ar supersonic gas jet irradiated by femtosecond near-infrared-wavelength laser pulses

Science.gov (United States)

Kantsyrev, V. L.; Schultz, K. A.; Shlyaptseva, V. V.; Petrov, G. M.; Safronova, A. S.; Petkov, E. E.; Moschella, J. J.; Shrestha, I.; Cline, W.; Wiewior, P.; Chalyy, O.

2016-11-01

Many aspects of physical phenomena occurring when an intense laser pulse with subpicosecond duration and an intensity of 1018-1019W /cm2 heats an underdense plasma in a supersonic clustered gas jet are studied to determine the relative contribution of thermal and nonthermal processes to soft- and hard-x-ray emission from debris-free plasmas. Experiments were performed at the University of Nevada, Reno (UNR) Leopard laser operated with a 15-J, 350-fs pulse and different pulse contrasts (107 or 105). The supersonic linear (elongated) nozzle generated Xe cluster-monomer gas jets as well as jets with Kr-Ar or Xe-Kr-Ar mixtures with densities of 1018-1019cm-3 . Prior to laser heating experiments, all jets were probed with optical interferometry and Rayleigh scattering to measure jet density and cluster distribution parameters. The supersonic linear jet provides the capability to study the anisotropy of x-ray yield from laser plasma and also laser beam self-focusing in plasma, which leads to efficient x-ray generation. Plasma diagnostics included x-ray diodes, pinhole cameras, and spectrometers. Jet signatures of x-ray emission from pure Xe gas, as well as from a mixture with Ar and Kr, was found to be very different. The most intense x-ray emission in the 1-9 KeV spectral region was observed from gas mixtures rather than pure Xe. Also, this x-ray emission was strongly anisotropic with respect to the direction of laser beam polarization. Non-local thermodynamic equilibrium (Non-LTE) models have been implemented to analyze the x-ray spectra to determine the plasma temperature and election density. Evidence of electron beam generation in the supersonic jet plasma was found. The influence of the subpicosecond laser pulse contrast (a ratio between the laser peak intensity and pedestal pulse intensity) on the jets' x-ray emission characteristics is discussed. Surprisingly, it was found that the x-ray yield was not sensitive to the prepulse contrast ratio.

A CIRCULAR-RIBBON SOLAR FLARE FOLLOWING AN ASYMMETRIC FILAMENT ERUPTION

Energy Technology Data Exchange (ETDEWEB)

Liu, Chang; Deng, Na; Lee, Jeongwoo; Wang, Haimin [Space Weather Research Laboratory, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982 (United States); Liu, Rui [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei 230026 (China); Pariat, Étienne [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universits, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, F-92190 Meudon (France); Wiegelmann, Thomas [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig Weg 3, D-37077 Göttingen (Germany); Liu, Yang [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305-4085 (United States); Kleint, Lucia, E-mail: chang.liu@njit.edu [University of Applied Sciences and Arts Northwestern Switzerland, Bahnhofstrasse 6, 5210 Windisch (Switzerland)

2015-10-20

The dynamic properties of flare ribbons and the often associated filament eruptions can provide crucial information on the flaring coronal magnetic field. This Letter analyzes the GOES-class X1.0 flare on 2014 March 29 (SOL2014-03-29T17:48), in which we found an asymmetric eruption of a sigmoidal filament and an ensuing circular flare ribbon. Initially both EUV images and a preflare nonlinear force-free field model show that the filament is embedded in magnetic fields with a fan-spine-like structure. In the first phase, which is defined by a weak but still increasing X-ray emission, the western portion of the sigmoidal filament arches upward and then remains quasi-static for about five minutes. The western fan-like and the outer spine-like fields display an ascending motion, and several associated ribbons begin to brighten. Also found is a bright EUV flow that streams down along the eastern fan-like field. In the second phase that includes the main peak of hard X-ray (HXR) emission, the filament erupts, leaving behind two major HXR sources formed around its central dip portion and a circular ribbon brightened sequentially. The expanding western fan-like field interacts intensively with the outer spine-like field, as clearly seen in running difference EUV images. We discuss these observations in favor of a scenario where the asymmetric eruption of the sigmoidal filament is initiated due to an MHD instability and further facilitated by reconnection at a quasi-null in corona; the latter is in turn enhanced by the filament eruption and subsequently produces the circular flare ribbon.

X-ray astronomy

International Nuclear Information System (INIS)

Giacconi, R.; Gursky, H.

1974-01-01

This text contains ten chapters and three appendices. Following an introduction, chapters two through five deal with observational techniques, mechanisms for the production of x rays in a cosmic setting, the x-ray sky and solar x-ray emission. Chapters six through ten include compact x-ray sources, supernova remnants, the interstellar medium, extragalactic x-ray sources and the cosmic x-ray background. Interactions of x rays with matter, units and conversion factors and a catalog of x-ray sources comprise the three appendices. (U.S.)

A miniature X-ray tube based on carbon nanotube for an intraoral dental radiography

International Nuclear Information System (INIS)

Kim, Hyun Jin; Park, Han Beom; Lee, Ju Hyuk; Cho, Sung Oh

2016-01-01

The number of human teeth that can be radiographically taken is limited. Moreover, at least two X-ray shots are required to get images of teeth from both sides of the mouth. In order to overcome the disadvantages of conventional dental radiography, a dental radiograph has been proposed in which an X-ray tube is inserted into the mouth while an X-ray detector is placed outside the mouth. The miniature X-ray tube is required small size to insert into the mouth. Recently, we have fabricated a miniature x-ray tube with the diameter of 7 mm using a carbon nanotube (CNT) field. But, commercialized miniature X-ray tube were adopted a thermionic type using tungsten filament. The X-ray tubes adopted thermionic emission has a disadvantage of increasing temperature of x-ray tube. So it need to cooling system to cool x-ray tube. On the other hands, X-ray tubes adopted CNT field emitters don't need cooling systems because electrons are emitted from CNT by applying high voltage without heating. We have developed the miniature x-ray tube that produce x-ray with uniform spatial distribution based on carbon nanotube field emitters. The fabricated miniature x-ray tube can be stably and reliably operated at 50kV without any vacuum pump. The developed miniature X-ray tube was applied for intraoral dental radiography that employs an intra-oral CNT-based miniature X-ray tube and extra-oral X-ray detectors. An X-ray image of many teeth was successfully obtained by a single X-ray shot using the intra-oral miniature X-ray tube system. Furthermore, images of both molar teeth of pig were simultaneously obtained by a single X-ray shot. These results show that the intraoral dental radiography, which employs an intraoral miniature X-ray tube and an extraoral X-ray detector, performs better than conventional dental radiography

A miniature X-ray tube based on carbon nanotube for an intraoral dental radiography

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyun Jin; Park, Han Beom; Lee, Ju Hyuk; Cho, Sung Oh [KAIST, Daejeon (Korea, Republic of)

2016-05-15

The number of human teeth that can be radiographically taken is limited. Moreover, at least two X-ray shots are required to get images of teeth from both sides of the mouth. In order to overcome the disadvantages of conventional dental radiography, a dental radiograph has been proposed in which an X-ray tube is inserted into the mouth while an X-ray detector is placed outside the mouth. The miniature X-ray tube is required small size to insert into the mouth. Recently, we have fabricated a miniature x-ray tube with the diameter of 7 mm using a carbon nanotube (CNT) field. But, commercialized miniature X-ray tube were adopted a thermionic type using tungsten filament. The X-ray tubes adopted thermionic emission has a disadvantage of increasing temperature of x-ray tube. So it need to cooling system to cool x-ray tube. On the other hands, X-ray tubes adopted CNT field emitters don't need cooling systems because electrons are emitted from CNT by applying high voltage without heating. We have developed the miniature x-ray tube that produce x-ray with uniform spatial distribution based on carbon nanotube field emitters. The fabricated miniature x-ray tube can be stably and reliably operated at 50kV without any vacuum pump. The developed miniature X-ray tube was applied for intraoral dental radiography that employs an intra-oral CNT-based miniature X-ray tube and extra-oral X-ray detectors. An X-ray image of many teeth was successfully obtained by a single X-ray shot using the intra-oral miniature X-ray tube system. Furthermore, images of both molar teeth of pig were simultaneously obtained by a single X-ray shot. These results show that the intraoral dental radiography, which employs an intraoral miniature X-ray tube and an extraoral X-ray detector, performs better than conventional dental radiography.

High-Resolution X-ray Emission and X-ray Absorption Spectroscopy

NARCIS (Netherlands)

Groot, F.M.F. de

2000-01-01

In this review, high-resolution X-ray emission and X-ray absorption spectroscopy will be discussed. The focus is on the 3d transition-metal systems. To understand high-resolution X-ray emission and reso-nant X-ray emission, it is first necessary to spend some time discussing the X-ray absorption

The Multi-component X-ray Emission of 3C 273

Science.gov (United States)

Soldi, S.; Türler, M.; Paltani, S.; Courvoisier, T. J.-L.

2009-05-01

3C 273 is the brightest quasar in the sky and among the most extensively observed and studied AGN, therefore one of the most suitable targets for a long-term, multi-frequency study. The superposition of a thermal Comptonisation component, similar to that observed in Seyfert galaxies, and of a non-thermal component, related to the jet emission, seems to explain some of the spectral and timing properties of the X-ray emission of 3C 273. Yet, during some observations this dichotomy has not been observed and the variability properties could also be consistent with a single-component scenario, characterised by two parameters varying independently. In order to understand the nature of the X-ray emission in 3C 273, a series of observations up to 80-100 keV, possibly catching the source in different flux states, are essential. Simbol-X will be able to study the emission of 3C 273 in the broad 0.5-80 keV band with high sensitivity, allowing us to disentangle the emission from different spectral components, with 20-30 ks long observations. In addition, the shape and the origin of the high-energy emission of this quasar will be further constrained thanks to the AGILE and Fermi satellites, monitoring the γ-ray sky in the MeV-GeV energy domain.

Flash X-ray

International Nuclear Information System (INIS)

Sato, Eiichi

2003-01-01

Generation of quasi-monochromatic X-ray by production of weakly ionized line plasma (flash X-ray), high-speed imaging by the X-ray and high-contrast imaging by the characteristic X-ray absorption are described. The equipment for the X-ray is consisted from the high-voltage power supply and condenser, turbo molecular pump, and plasma X-ray tube. The tube has a long linear anticathode to produce the line plasma and flash X-ray at 20 kA current at maximum. X-ray spectrum is measured by the imaging plate equipped in the computed radiography system after diffracted by a LiF single crystal bender. Cu anticathode generates sharp peaks of K X-ray series. The tissue images are presented for vertebra, rabbit ear and heart, and dog heart by X-ray fluoroscopy with Ce anticathode. Generation of K-orbit characteristic X-ray with extremely low bremsstrahung is to be attempted for medical use. (N.I.)

Room temperature CVD diamond X-ray and charged particle microdetectors

CERN Document Server

Vittone, E; Lo Giudice, A; Polesello, P; Manfredotti, C

1999-01-01

Hot filament chemical vapour deposition technique is particularly suitable for the realisation of diamond tip and wire detectors working in a coaxial geometry with a built-in internal metal electrode. By using tungsten wires of different diameters and by controlling the shape of the tip by an electrochemical etch, it is possible to obtain various kinds of microdetectors, with diameters ranging from 50 to 300 mu m. The response of these diamond tip and wire detectors has been tested at low X-ray energies (50-250 keV) and at relatively high energies (6-15 MeV) both in terms of sensitivity (collected charge with respect to the absorbed dose) and of linearity as a function of X-ray fluence. Sensitivities larger than 2 nC/Gy are achieved, with a good linearity in the dose rate range used in applications. Such microprobes have been proved to be suitable as narrow X-ray beam profilers and as surface or in vivo microdosimeters for on-line monitoring of radiotherapy plans. Such detectors have also been used as nuclear...

The 2017 Periastron Passage of PSR B1259-63 in Gamma-rays and X-rays

Science.gov (United States)

Wood, Kent S.; Johnson, Tyrel; Ray, Paul S.; Kerr, Matthew T.; Chernyakova, Masha; Fermi LAT Collaboration

2018-01-01

PSR B1259‑ 63 is a 48-ms radio pulsar in a highly eccentric 3.4-yr orbit with a Be star LS 2883. While the pulsed emission has been detected only in radio, un-pulsed radio, X-ray and gamma-ray emission are regularly observed from the binary system around the periastron. It is likely that the collision of the pulsar wind with the anisotropic wind of the Be star plays a crucial role in the generation of the observed non-thermal emission. The spectral energy distribution observed near periastron peaks in GeV gamma-rays, reaching maximum flux several weeks past periastron. In September 2017 it is being observed for a third periastron passage by the Fermi satellite. Here we present first results of the 2017 multi-wavelength campaign. The 2017 observations are compared to the two previous cycles, and used to test current models. Until recently there was no similar source known in the Galaxy but now a near-twin to it, PSR J2032+4127 , (Pspin=143 ms, Porbit ~50 yr, detectable radio to gamma rays) has been found, and is also undergoing periastron passage in Nov 2017. Gamma-ray and X-ray phenomena in the two sources are compared and discussed. These objects may represent a transitional phase, with possible later phases being accreting pulsars, and eventually perhaps NS-BH or NS-NS binary systems. Portions of this research performed at the US Naval Research Laboratory are sponsored by NASA DPR S-15633-Y.

Reconnection, Particle Acceleration, and Hard X-ray Emission in Eruptive Solar Flares

Science.gov (United States)

Martens, Petrus C.

1998-11-01

The frequent occurrence of Hard X-ray emission from the top of flaring loops was one of the discoveries by the Hard X-ray telescope on board the Japanese Yohkoh satellite. I will show how the combined effect of magnetic field convergence and pitch- angle scattering of non-thermal electrons injected at the top of the loop results in the generation of looptop sources with properties akin to those observed by Yohkoh. In addition it is shown that the injection of proton beams in the loop legs, expected from theory, reproduces the observed high temperature ``ridges" in the loop legs by mirroring and energy loss through collisions. I will interpret these numerical results as supporting the now widely accepted model of an erupting magnetic flux tube generating a reconnecting current sheet in its wake, where most of the energy release takes place. The strong similarity with the reconnection observed in the MRX experiment in Princeton will be analyzed in detail.

The size of coronal hard X-ray sources in solar flares: How big are they?

Science.gov (United States)

Effenberger, F.; Krucker, S.; Rubio da Costa, F.

2017-12-01

Coronal hard X-ray sources are considered to be one of the key signatures of non-thermal particle acceleration and heating during the energy release in solar flares. In some cases, X-ray observations reveal multiple components spatially located near and above the loop top and even further up in the corona. Here, we combine a detailed RHESSI imaging analysis of near-limb solar flares with occulted footpoints and a multi-wavelength study of the flare loop evolution in SDO/AIA. We connect our findings to different current sheet formation and magnetic break-out scenarios and relate it to particle acceleration theory. We find that the upper and usually fainter emission regions can be underestimated in their size due to the majority of flux originating from the lower loops.

X-Ray

Science.gov (United States)

... enema. What you can expect During the X-ray X-rays are performed at doctors' offices, dentists' offices, ... as those using a contrast medium. Your child's X-ray Restraints or other techniques may be used to ...

On the Non-Thermal Energy Content of Cosmic Structures

Directory of Open Access Journals (Sweden)

Franco Vazza

2016-11-01

Full Text Available (1 Background: the budget of non-thermal energy in galaxy clusters is not well constrained, owing to the observational and theoretical difficulties in studying these diluted plasmas on large scales; (2 Method: we use recent cosmological simulations with complex physics in order to connect the emergence of non-thermal energy to the underlying evolution of gas and dark matter; (3 Results: the impact of non-thermal energy (e.g., cosmic rays, magnetic fields and turbulent motions is found to increase in the outer region of galaxy clusters. Within numerical and theoretical uncertainties, turbulent motions dominate the budget of non-thermal energy in most of the cosmic volume; (4 Conclusion: assessing the distribution non-thermal energy in galaxy clusters is crucial to perform high-precision cosmology in the future. Constraining the level of non-thermal energy in cluster outskirts will improve our understanding of the acceleration of relativistic particles and of the origin of extragalactic magnetic fields.

Galaxy Cluster Outskirts from the Thermal SZ and Non-Thermal Synchrotron Link

Directory of Open Access Journals (Sweden)

Kaustuv Basu

2016-11-01

Full Text Available Galaxy cluster merger shocks are the main agent for the thermalization of the intracluster medium and the energization of cosmic ray particles in it. Shock propagation changes the state of the tenuous intracluster plasma, and the corresponding signal variations are measurable with the current generation of X-ray and Sunyaev–Zel’dovich (SZ effect instruments. Additionally, non-thermal electrons (re-energized by the shocks sometimes give rise to extended and luminous synchrotron sources known as radio relics, which are prominent indicators of shocks propagating roughly in the plane of the sky. In this short review, we discuss how the joint modeling of the non-thermal and thermal signal variations across radio relic shock fronts is helping to advance our knowledge of the gas thermodynamical properties and magnetic field strengths in the cluster outskirts. We describe the first use of the SZ effect to measure the Mach numbers of relic shocks, for both the nearest (Coma and the farthest (El Gordo clusters with known radio relics.

Synchrotron x-ray microbeam characteristics for x-ray fluorescence analysis

International Nuclear Information System (INIS)

Iida, Atsuo; Noma, Takashi

1995-01-01

X-ray fluorescence analysis using a synchrotron x-ray microprobe has become an indispensable technique for non-destructive micro-analysis. One of the most important parameters that characterize the x-ray microbeam system for x-ray fluorescence analysis is the beam size. For practical analysis, however, the photon flux, the energy resolution and the available energy range are also crucial. Three types of x-ray microbeam systems, including monochromatic and continuum excitation systems, were compared with reference to the sensitivity, the minimum detection limit and the applicability to various types of x-ray spectroscopic analysis. 16 refs., 5 figs

X-ray sky

International Nuclear Information System (INIS)

Gruen, M.; Koubsky, P.

1977-01-01

The history is described of the discoveries of X-ray sources in the sky. The individual X-ray detectors are described in more detail, i.e., gas counters, scintillation detectors, semiconductor detectors, and the principles of X-ray spectrometry and of radiation collimation aimed at increased resolution are discussed. Currently, over 200 celestial X-ray sources are known. Some were identified as nebulae, in some pulsations were found or the source was identified as a binary star. X-ray bursts of novae were also observed. The X-ray radiation is briefly mentioned of spherical star clusters and of extragalactic X-ray sources. (Oy)

X-ray astronomy

International Nuclear Information System (INIS)

Culhane, J.L.; Sanford, P.W.

1981-01-01

X-ray astronomy has been established as a powerful means of observing matter in its most extreme form. The energy liberated by sources discovered in our Galaxy has confirmed that collapsed stars of great density, and with intense gravitational fields, can be studied by making observations in the X-ray part of the electromagnetic spectrum. The astronomical objects which emit detectable X-rays include our own Sun and extend to quasars at the edge of the Universe. This book describes the history, techniques and results obtained in the first twenty-five years of exploration. Space rockets and satellites are essential for carrying the instruments above the Earth's atmosphere where it becomes possible to view the X-rays from stars and nebulae. The subject is covered in chapters, entitled: the birth of X-ray astronomy; the nature of X-radiation; X-rays from the Sun; solar-flare X-rays; X-rays from beyond the solar system; supernovae and their remnants; X-rays from binary stars; white dwarfs and neutron stars; black holes; X-rays from galaxies and quasars; clusters of galaxies; the observatories of the future. (author)

The Nuclear Spectroscopic Telescope Array (NuSTAR) High-Energy X-ray Mission

Science.gov (United States)

Harrison, Fiona A.; Craig, Willliam W.; Christensen, Finn E.; Hailey, Charles J.; Zhang, William W.; Boggs, Steven E.; Stern, Daniel; Cook, W. Rick; Forster, Karl; Giommi, Paolo;

Skull x-ray

Science.gov (United States)

X-ray - head; X-ray - skull; Skull radiography; Head x-ray ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

Neck x-ray

Science.gov (United States)

X-ray - neck; Cervical spine x-ray; Lateral neck x-ray ... There is low radiation exposure. X-rays are monitored so that the lowest amount of radiation is used to produce the image. Pregnant women and ...

X-ray filter for chest X-rays

International Nuclear Information System (INIS)

Ferlic, D.J.

1984-01-01

A description is given of an X-ray filter comprised of a sheet of radiation absorbing material with an opening corresponding to the spine and central portion of the heart. The upper portion of the filter exhibits a relatively narrow opening which becomes gradually wider toward the lower portion of the filter. This filter will permit an acceptable density level of x-ray exposure for the lungs while allowing a higher level of x-ray exposure for the mediastinum areas of the body. (author)

A Survery of the Correlation between Filament Chirality and Sigmoid Handedness

Science.gov (United States)

V, A.; Hazra, S.; Martin, S. F.; Martens, P. C.

2017-12-01

Sigmoid regions on the Sun are often the regions that cause Coronal Mass Ejections (CMEs). Large CMEs most often have filaments that erupt with them. This study focuses on the statistical relevance of the shape of the sigmoid and the chirality of the filament residing in these sigmoids. The study further extends to the relation between the directionality of filaments and the Earth-directed CMEs. Sigmoid data from Savcheva et al. (2014) between 2007 and 2012 and a compilation of data using the HEK Sigmoid Sniffer (Martens et al. 2012) along with Hinode XRT Soft X-ray images were used for analyzing data between 2013 and 2017. Hence this dataset consists of almost one solar cycle of data. A similar study done previously by Martens et al. (2013) analysed data for a solar cycle using an Advanced Automated Filament Detection & Characterization Code (Bernasconi, Rust & Hakim 2005). Considering that automated chirality detection is not foolproof, we present this study which uses manual determination of chirality for accuracy using high resolution chromospheric images. Mainly full disk images of soft X-ray obtained from Hinode XRT (X-Ray Telescope) have been used to find and ensure the S or Z shape of sigmoids. H-alpha images obtained from BBSO and Kanzelhohe Solar Observatory (KSO) are used in determining the chirality of filaments. The resolutions of BBSO and KSO data are 1k and 4k respectively. A comparison of the analysis of the chirality of filaments using both data will be presented. Although KSO gives a 4k resolution, it is still difficult to determine the chirality of small filaments. For this reason, high resolution images of H-alpha chromospheric filaments obtained from Helio Research and Solar Observing Optical Network (SOON) have been used for further analysis of chirality of those filaments that were undeterminable using the BBSO or KSO full disk images. The results of the comparison using the different resolutions are shown. The results of the correlation

ELECTRON ENERGY PARTITION IN THE ABOVE-THE-LOOPTOP SOLAR HARD X-RAY SOURCES

Energy Technology Data Exchange (ETDEWEB)

Oka, Mitsuo; Krucker, Säm; Hudson, Hugh S.; Saint-Hilaire, Pascal, E-mail: moka@ssl.berkeley.edu [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)

2015-02-01

Solar flares produce non-thermal electrons with energies up to tens of MeVs. To understand the origin of energetic electrons, coronal hard X-ray (HXR) sources, in particular above-the-looptop sources, have been studied extensively. However, it still remains unclear how energies are partitioned between thermal and non-thermal electrons within the above-the-looptop source. Here we show that the kappa distribution, when compared to conventional spectral models, can better characterize the above-the-looptop HXRs (≳15 keV) observed in four different cases. The widely used conventional model (i.e., the combined thermal plus power-law distribution) can also fit the data, but it returns unreasonable parameter values due to a non-physical sharp lower-energy cutoff E{sub c}. In two cases, extreme-ultraviolet data were available from SDO/AIA and the kappa distribution was still consistent with the analysis of differential emission measure. Based on the kappa distribution model, we found that the 2012 July 19 flare showed the largest non-thermal fraction of electron energies about 50%, suggesting equipartition of energies. Considering the results of particle-in-cell simulations, as well as density estimates of the four cases studied, we propose a scenario in which electron acceleration is achieved primarily by collisionless magnetic reconnection, but the electron energy partition in the above-the-looptop source depends on the source density. In low-density above-the-looptop regions (few times 10{sup 9} cm{sup –3}), the enhanced non-thermal tail can remain and a prominent HXR source is created, whereas in higher-densities (>10{sup 10} cm{sup –3}), the non-thermal tail is suppressed or thermalized by Coulomb collisions.

X-ray optics and X-ray microscopes: new challenges

International Nuclear Information System (INIS)

Susini, J.

2004-01-01

Soon after the discovery of X-rays in 1895 by W. Roentgen, it became rapidly clear that the methods traditionally used in the visible light regime, namely refraction, diffraction and reflection were difficult to apply for X-ray optics. The physical origins of these difficulties are closely linked to the very nature of interaction of X-rays with matter. The small deviation δ of the refractive index of condensed matter from unity makes it difficult to extend refraction-based optics from the optical spectral region to the X-ray region because the refraction angle is proportional to δ. Similarly it is very challenging to extend diffraction-based focusing techniques to X-rays because the diffraction angle scales inversely with wavelength. Finally, the use of reflection-based optics is also limited by the very small critical angle for total reflection. All those fundamental limitations prevented for almost one century, the development of X-ray microscopy whereas electron microscopy became a standard tool. In the past twenty years, interests for X-ray microscopy revived, mainly because of several major advances in X-ray sources and X-ray optics. X-ray microscopy techniques are now emerging as powerful and complementary tools for submicron investigations. Soft X-ray microscopes offer traditionally the possibility to form direct images of thick hydrated biological material in near-native environment, at a spatial resolution well beyond that achievable with visible light microscopy. Natural contrast is available in the soft X-ray region, in the so-called ''water-window'', due to the presence of absorption edges of the major constituents (C,N,O). Recent advances in manufacturing techniques have enlarged the accessible energy range of micro-focussing optics and offer new applications in a broad range of disciplines. X-ray microscopy in the 1 - 30 keV energy range is better suited for fluorescence to map trace elements, tomography for 3D imaging and micro-diffraction. The

X-ray filter for chest x-rays

International Nuclear Information System (INIS)

Ferlic, D.J.

1984-01-01

Filter for use in medical x-ray apparatus to permit higher intensity x-ray exposure in the heart and mediastinum area while maintaining a normal level of x-ray exposure in other areas of the body, particlarly in the lung area. The filter comprises a sheet of radiation absorbing material having an opening therein, said opening corresponding to the spine and central portion of the heart. Accordingly, the upper portion of the filter exhibits a relatively narrow opening which becomes gradually wider toward the lower portion of the filter

Topics in High-Energy Astrophysics: X-ray Time Lags and Gamma-ray Flares

Science.gov (United States)

Kroon, John J.

2016-03-01

The Universe is host to a wide variety of high-energy processes that convert gravitational potential energy or rest-mass energy into non-thermal radiation such as bremsstrahlung and synchrotron. Prevailing models of X-ray emission from accreting Black Hole Binaries (BHBs) struggle to simultaneously fit the quiescent X-ray spectrum and the transients which result in the phenomenon known as X-ray time lags. And similarly, classical models of diffusive shock acceleration in pulsar wind nebulae fail to explain the extreme particle acceleration in very short timescales as is inferred from recent gamma-ray flares from the Crab nebula. In this dissertation, I develop new exact analytic models to shed light on these intriguing processes. I take a fresh look at the formation of X-ray time lags in compact sources using a new mathematical approach in which I obtain the exact Green's function solution. The resulting Green's function allows one to explore a variety of injection scenarios, including both monochromatic and broadband (bremsstrahlung) seed photon injection. I obtain the exact solution for the dependence of the time lags on the Fourier frequency, for both homogeneous and inhomogeneous clouds. The model can successfully reproduce both the observed time lags and the quiescent X-ray spectrum using a single set of coronal parameters. I show that the implied coronal radii in the new model are significantly smaller than those obtained in the Monte Carlo simulations, hence greatly reducing the coronal heating problem. Recent bright gamma-ray flares from the Crab nebula observed by AGILE and Fermi reaching GeV energies and lasting several days challenge the contemporary model for particle acceleration in pulsar wind nebulae, specifically the diffusive shock acceleration model. Simulations indicate electron/positron pairs in the Crab nebula pulsar wind must be accelerated up to PeV energies in the presence of ambient magnetic fields with strength B ~100 microG. No

Discovery of X-Ray Emission from the Galactic Supernova Remnant G32.8-0.1 with Suzaku

Science.gov (United States)

Bamba, Aya; Terada, Yukikatsu; Hewitt, John; Petre, Robert; Angelini, Lorella; Safi-Harb, Samar; Zhou, Ping; Bocchino, Fabrizio; Sawada, Makoto

2016-01-01

We present the first dedicated X-ray study of the supernova remnant (SNR) G32.8-0.1 (Kes 78) with Suzaku. X-ray emission from the whole SNR shell has been detected for the first time. The X-ray morphology is well correlated with the emission from the radio shell, while anti-correlated with the molecular cloud found in the SNR field. The X-ray spectrum shows not only conventional low-temperature (kT approximately 0.6 kiloelectronvolts) thermal emission in a nonequilibrium ionization state, but also a very high-temperature (approximately 3.4 kiloelectronvolts) component with a very low ionization timescale (approximately 2.7 times 10 (sup 9) per cubic centimeter per second), or a hard nonthermal component with a photon index Gamma approximately equal to 2.3. The average density of the low-temperature plasma is rather low, of the order of 10 (sup -3) - 10 (sup -2) per cubic centimeter, implying that this SNR is expanding into a low-density cavity. We discuss the X-ray emission of the SNR, also detected in teraelectronvolts with H.E.S.S. (High Energy Stereoscopic System), together with multi-wavelength studies of the remnant and other gamma-ray emitting SNRs, such as W28 and RCW 86. Analysis of a time-variable source, 2XMM J185114.3-000004, found in the northern part of the SNR, is also reported for the first time. Rapid time variability and a heavily absorbed hard-X-ray spectrum suggest that this source could be a new supergiant fast X-ray transient.

SENSITIVITY OF STACKED IMAGING DETECTORS TO HARD X-RAY POLARIZATION

Energy Technology Data Exchange (ETDEWEB)

Muleri, Fabio; Campana, Riccardo, E-mail: fabio.muleri@iaps.inaf.it [INAF-IAPS, Via del Fosso del Cavaliere 100, I-00133 Roma (Italy)

2012-06-01

The development of multi-layer optics which allow to focus photons up to 100 keV and more promises an enormous jump in sensitivity in the hard X-ray energy band. This technology is already planned to be exploited by future missions dedicated to spectroscopy and imaging at energies >10 keV, e.g., Astro-H and NuSTAR. Nevertheless, our understanding of the hard X-ray sky would greatly benefit from carrying out contemporaneous polarimetric measurements, because the study of hard spectral tails and of polarized emission are often two complementary diagnostics of the same non-thermal and acceleration processes. At energies above a few tens of keV, the preferred technique to detect polarization involves the determination of photon directions after a Compton scattering. Many authors have asserted that stacked detectors with imaging capabilities can be exploited for this purpose. If it is possible to discriminate those events which initially interact in the first detector by Compton scattering and are subsequently absorbed by the second layer, then the direction of scattering is singled out from the hit pixels in the two detectors. In this paper, we give the first detailed discussion of the sensitivity of such a generic design to the X-ray polarization. The efficiency and the modulation factor are calculated analytically from the geometry of the instruments and then compared with the performance as derived by means of Geant4 Monte Carlo simulations.

Simultaneous radio and x-ray activity in SS 433

International Nuclear Information System (INIS)

Seaquist, E.R.; Gilmore, W.S.; Johnston, K.J.; Grindlay, J.E.

1982-01-01

Simultaneous observations at radio and X-ray wavelengths of flarelike events in SS 433 were made during 1979 October 5-9 and 19-22. The radio spectra show evidence for low-frequency absorption, which may be due to either synchrotron self-absorption or free-free absorption by a stellar wind. In the latter case, a model is developed indicating that clouds of relativistic gas are generated at least 10 14 cm from the stellar object and are swept outward through the stellar wind by highly collimated beams. A mass loss of approx.10 -5 M/sub sun/ yr -1 and an outflow speed of approx.1000 km s -1 are consistent with the data. The beam velocities (0.26c) are found to be consistent with the previous optical and radio data. The X-ray emission is evidently nonthermal and closely related to the radio flares, particularly during the event on October 5-9. The behavior during the second event on October 19-22 is considerably more complex. The source of the X-ray radiation is either synchrotron or inverse Compton emission. No clear cut decision is permitted by the data, although the latter mechanism seems to be an inevitable consequence of the known presence of both ultrarelativistic electrons and a high optical stellar luminosity. The inverse Compton mechansim is considered in more detail in the context of the model used to explain the radio behavior. The complexity of the October 19-22 data seems to defy' any simple model

X-ray geometrical smoothing effect in indirect x-ray-drive implosion

International Nuclear Information System (INIS)

Mochizuki, Takayasu; Sakabe, Shuji; Yamanaka, Chiyoe

1983-01-01

X-ray geometrical smoothing effect in indirect X-ray drive pellet implosion for inertial confinement fusion has been numerically analyzed. Attainable X-ray driven ablation pressure has been found to be coupled with X-ray irradiation uniformity. (author)

Different X-ray spectral evolution for black hole X-ray binaries in dual tracks of radio-X-ray correlation

International Nuclear Information System (INIS)

Cao, Xiao-Feng; Wu, Qingwen; Dong, Ai-Jun

2014-01-01

Recently, an 'outlier' track of radio-X-ray correlation was found, which is much steeper than the former universal correlation, where dual tracks were speculated to be triggered by different accretion processes. In this work, we test this issue by exploring hard X-ray spectral evolution in four black-hole X-ray binaries with multiple, quasi-simultaneous radio and X-ray observations. First, we find that hard X-ray photon indices, Γ, are negatively and positively correlated with X-ray fluxes when the X-ray flux, F 3-9 keV , is below and above a critical flux, F X, crit , which are consistent with predictions of the advection-dominated accretion flow and the disk-corona model, respectively. Second, and most importantly, we find that the radio-X-ray correlations are also clearly different when the X-ray fluxes are higher and lower than the critical flux as defined by X-ray spectral evolution. The data points with F 3-9 keV ≳ F X, crit have a steeper radio-X-ray correlation (F X ∝F R b and b ∼ 1.1-1.4), which roughly forms the ''outlier'' track. However, the data points with anti-correlation of Γ – F 3-9 keV either stay in the universal track with b ∼ 0.61 or stay in the transition track (from the universal to 'outlier' tracks or vice versa). Therefore, our results support that the universal and ''outlier'' tracks of radio-X-ray correlations are regulated by radiatively inefficient and radiatively efficient accretion model, respectively.

Nonthermal Particle Acceleration in 3D Relativistic Magnetic Reconnection in Pair Plasma

Energy Technology Data Exchange (ETDEWEB)

Werner, Gregory R.; Uzdensky, Dmitri A., E-mail: Greg.Werner@colorado.edu [Center for Integrated Plasma Studies, Physics Department, University of Colorado, 390 UCB, Boulder, CO 80309 (United States)

2017-07-10

As a fundamental process converting magnetic to plasma energy in high-energy astrophysical plasmas, relativistic magnetic reconnection is a leading explanation for the acceleration of particles to the ultrarelativistic energies that are necessary to power nonthermal emission (especially X-rays and gamma-rays) in pulsar magnetospheres and pulsar wind nebulae, coronae and jets of accreting black holes, and gamma-ray bursts. An important objective of plasma astrophysics is therefore the characterization of nonthermal particle acceleration (NTPA) effected by reconnection. Reconnection-powered NTPA has been demonstrated over a wide range of physical conditions using large 2D kinetic simulations. However, its robustness in realistic 3D reconnection—in particular, whether the 3D relativistic drift-kink instability (RDKI) disrupts NTPA—has not been systematically investigated, although pioneering 3D simulations have observed NTPA in isolated cases. Here, we present the first comprehensive study of NTPA in 3D relativistic reconnection in collisionless electron–positron plasmas, characterizing NTPA as the strength of 3D effects is varied systematically via the length in the third dimension and the strength of the guide magnetic field. We find that, while the RDKI prominently perturbs 3D reconnecting current sheets, it does not suppress particle acceleration, even for zero guide field; fully 3D reconnection robustly and efficiently produces nonthermal power-law particle spectra closely resembling those obtained in 2D. This finding provides strong support for reconnection as the key mechanism powering high-energy flares in various astrophysical systems. We also show that strong guide fields significantly inhibit NTPA, slowing reconnection and limiting the energy available for plasma energization, yielding steeper and shorter power-law spectra.

Comparison of x-ray output of inverter-type x-ray equipment

International Nuclear Information System (INIS)

Asano, Hiroshi; Miyake, Hiroyuki; Yamamoto, Keiichi

2000-01-01

The x-ray output of 54 inverter-type x-ray apparatuses used at 18 institutions was investigated. The reproducibility and linearity of x-ray output and variations among the x-ray equipment were evaluated using the same fluorescence meter. In addition, the x-ray apparatuses were re-measured using the same non-invasive instrument to check for variations in tube voltage, tube current, and irradiation time. The non-invasive instrument was calibrated by simultaneously obtaining measurements with an invasive instrument, employing the tube voltage and current used for the invasive instrument, and the difference was calculated. Reproducibility of x-ray output was satisfactory for all x-ray apparatuses. The coefficient of variation was 0.04 or less for irradiation times of 5 ms or longer. In 84.3% of all x-ray equipment, variation in the linearity of x-ray output was 15% or less for an irradiation time of 5 ms. However, for all the apparatuses, the figure was 50% when irradiation time was the shortest (1 to 3 ms). Variation in x-ray output increased as irradiation time decreased. Variation in x-ray output ranged between 1.8 and 2.5 compared with the maximum and minimum values, excluding those obtained at the shortest irradiation time. The relative standard deviation ranged from ±15.5% to ±21.0%. The largest variation in x-ray output was confirmed in regions irradiated for the shortest time, with smaller variations observed for longer irradiation times. The major factor responsible for variation in x-ray output in regions irradiated for 10 ms or longer, which is a relatively long irradiation time, was variation in tube current. Variation in tube current was slightly greater than 30% at maximum, with an average value of 7% compared with the preset tube current. Variations in x-ray output in regions irradiated for the shortest time were due to photographic effects related to the rise and fall times of the tube voltage waveform. Accordingly, in order to obtain constant x-ray

A tool to separate optical/infrared disc and jet emission in X-ray transient outbursts: the colour-magnitude diagrams of XTE J1550-564

NARCIS (Netherlands)

Russell, D.M.; Maitra, D.; Dunn, R.J.H.; Fender, R.P.

2011-01-01

It is now established that thermal disc emission and non-thermal jet emission can both play a role at optical/infrared (OIR) wavelengths in X-ray transients. The spectra of the jet and disc components differ, as do their dependence on mass accretion properties. Here we demonstrate that the OIR

Chest X-Ray

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Full Text Available ... about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed x-ray exams and use a very small dose of ... of the inside of the chest. A chest x-ray is used to evaluate the lungs, heart and ...

Modelling of X-ray emission supernova remnants observed by the European satellite XMM-Newton

International Nuclear Information System (INIS)

Cassam-Chenai, G.

2004-01-01

This thesis deals with the X-ray emission of supernova remnants (SNRs) observed by the European satellite XMM-Newton. In SNRs, the matter heated to millions of degrees shines brightly in X-rays. This emission depends on the hydrodynamical evolution of the SNR, on the chemical composition of the ejected matter and on the ambient medium. Moreover, the blast-wave is considered to be the prime site of the production and the acceleration of cosmic-rays in our Galaxy. XMM-Newton is one of the first to allow the investigation of these different aspects thanks to its spatially-resolved spectroscopy and its very good sensitivity. l first studied Kepler's SNR (SN 1604) whose X-ray emission is dominated by the ejecta. Its observation has allowed to obtain information on the nucleosynthesis products, on their spatial distribution and on the temperature structure in the shocked ejecta. This gives strong constraints on the physics of the explosion and on the progenitor's type. l have shown also that the X-ray emission at the shock is likely to be non-thermal. Then, l studied the SNR G347.3-0.5 whose X-ray emission is entirely due to the synchrotron radiation of relativistic (TeV) electrons accelerated at the shock. From five pointing, l made a full mapping of the X-ray emission characteristics (brightness, absorption and spectral index) at small scale. Combined to radio observations, these results have indicated a clear interaction between the SNR and molecular clouds located at 1 kpc and not at 6 kpc as previously estimated. Lastly, in the framework of a self-similar hydrodynamical model coupled with non-linear particle acceleration, l have obtained the synchrotron emission profile in SNRs, including the adiabatic and radiative losses of the accelerated electrons. (author) [fr

STEADY-STATE HADRONIC GAMMA-RAY EMISSION FROM 100-MYR-OLD FERMI BUBBLES

Energy Technology Data Exchange (ETDEWEB)

Crocker, Roland M.; Bicknell, Geoffrey V.; Sutherland, Ralph S. [Research School of Astronomy and Astrophysics, Australian National University, Canberra (Australia); Carretti, Ettore; Hill, Alex S. [CSIRO Astronomy and Space Science, Marsfield, N.S.W. (Australia)

2014-08-20

Fermi Bubbles are enigmatic γ-ray features of the Galactic bulge. Both putative activity (within few × Myr) connected to the Galactic center super-massive black hole and, alternatively, nuclear star formation have been claimed as the energizing source of the Bubbles. Likewise, both inverse-Compton emission by non-thermal electrons (''leptonic'' models) and collisions between non-thermal protons and gas (''hadronic'' models) have been advanced as the process supplying the Bubbles' γ-ray emission. An issue for any steady state hadronic model is that the very low density of the Bubbles' plasma seems to require that they accumulate protons over a multi-gigayear timescale, much longer than other natural timescales occurring in the problem. Here we present a mechanism wherein the timescale for generating the Bubbles' γ-ray emission via hadronic processes is ∼few × 10{sup 8} yr. Our model invokes the collapse of the Bubbles' thermally unstable plasma, leading to an accumulation of cosmic rays and magnetic field into localized, warm (∼10{sup 4} K), and likely filamentary condensations of higher-density gas. Under the condition that these filaments are supported by non-thermal pressure, the hadronic emission from the Bubbles is L {sub γ} ≅ 2 × 10{sup 37} erg s{sup –1} M-dot {sub in}/(0.1 M{sub ⊙} yr{sup –1} ) T{sub FB}{sup 2}/(3.5×10{sup 7} K){sup 2} M {sub fil}/M {sub pls}, equal to their observed luminosity (normalizing to the star-formation-driven mass flux into the Bubbles and their measured plasma temperature and adopting the further result that the mass in the filaments, M {sub fil} is approximately equal to the that of the Bubbles' plasma, M {sub pls})

Wide field X-ray telescopes: Detecting X-ray transients/afterglows related to gamma ray bursts

International Nuclear Information System (INIS)

Hudec, Rene; Pina, Ladislav; Inneman, Adolf; Gorenstein, Paul; Rezek, Tomas

1999-01-01

The recent discovery of X-ray afterglows of GRBs opens the possibility of analyses of GRBs by their X-ray detections. However, imaging X-ray telescopes in current use mostly have limited field of view. Alternative X-ray optics geometries achieving very large fields of view have been theoretically suggested in the 70ies but not constructed and used so far. We review the geometries and basic properties of the wide-field X-ray optical systems based on one- and two-dimensional lobster-eye geometry and suggest technologies for their development and construction. First results of the development of double replicated X-ray reflecting flats for use in one-dimensional X-ray optics of lobster eye type are presented and discussed. Optimum strategy for locating GRBs upon their X-ray counterparts is also presented and discussed

IMAGING SPECTROSCOPY ON PREFLARE CORONAL NONTHERMAL SOURCES ASSOCIATED WITH THE 2002 JULY 23 FLARE

International Nuclear Information System (INIS)

Asai, Ayumi; Nakajima, Hiroshi; Shimojo, Masumi; Yokoyama, Takaaki; Masuda, Satoshi; Krucker, Saem

2009-01-01

We present a detailed examination on the coronal nonthermal emissions during the preflare phase of the X4.8 flare that occurred on 2002 July 23. The microwave (17 GHz and 34 GHz) data obtained with Nobeyama Radioheliograph, at Nobeyama Solar Radio Observatory and the hard X-ray (HXR) data taken with RHESSI obviously showed nonthermal sources that are located above the flare loops during the preflare phase. We performed imaging spectroscopic analyses on the nonthermal emission sources both in microwaves and in HXRs, and confirmed that electrons are accelerated from several tens of keV to more than 1 MeV even in this phase. If we assume the thin-target model for the HXR emission source, the derived electron spectral indices (∼4.7) is the same value as that from microwaves (∼4.7) within the observational uncertainties, which implies that the distribution of the accelerated electrons follows a single power law. The number density of the microwave-emitting electrons is, however, larger than that of the HXR-emitting electrons, unless we assume low-ambient plasma density of about 1.0 x 10 9 cm -3 for the HXR-emitting region. If we adopt the thick-target model for the HXR emission source, on the other hand, the electron spectral index (∼6.7) is much different, while the gap of the number density of the accelerated electrons is somewhat reduced.

X-ray bursts observed with JEM-X

DEFF Research Database (Denmark)

Brandt, Søren Kristian; Chenevez, Jérôme; Lund, Niels

2006-01-01

We report on the search for X-ray bursts in the JEM-X X-ray monitor on INTEGRAL during the first two years of operations. More than 350 bursts from 25 different type-I X-ray burst sources were found.......We report on the search for X-ray bursts in the JEM-X X-ray monitor on INTEGRAL during the first two years of operations. More than 350 bursts from 25 different type-I X-ray burst sources were found....

Bone X-Ray (Radiography)

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Full Text Available ... Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive medical ...

Bone X-Ray (Radiography)

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Full Text Available ... Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small dose ... limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is ...

Bone X-Ray (Radiography)

Science.gov (United States)

... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

Abdomen X-Ray (Radiography)

Science.gov (United States)

... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Abdomen Abdominal x-ray uses a very small ... of an abdominal x-ray? What is abdominal x-ray? An x-ray (radiograph) is a noninvasive medical ...

CRL X-ray tube

International Nuclear Information System (INIS)

Kolchevsky, N.N.; Petrov, P.V.

2015-01-01

A novel types of X-ray tubes with refractive lenses are proposed. CRL-R X-ray tube consists of Compound Refractive Lens- CRL and Reflection X-ray tube. CRL acts as X-ray window. CRL-T X-ray consists of CRL and Transmission X-ray tube. CRL acts as target for electron beam. CRL refractive lens acts as filter, collimator, waveguide and focusing lens. Properties and construction of the CRL X-ray tube are discussed. (authors)

The multi-messenger approach to particle acceleration by massive stars: a science case for optical, radio and X-ray observatories

Science.gov (United States)

De Becker, Michaël

2018-04-01

Massive stars are extreme stellar objects whose properties allow for the study of some interesting physical processes, including particle acceleration up to relativistic velocities. In particular, the collisions of massive star winds in binary systems lead notably to acceleration of electrons involved in synchrotron emission, hence their identification as non-thermal radio emitters. This has been demonstrated for about 40 objects so far. The relativistic electrons are also expected to produce non-thermal high-energy radiation through inverse Compton scattering. This class of objects permits thus to investigate non-thermal physics through observations in the radio and high energy spectral domains. However, the binary nature of these sources introduces some stringent requirements to adequately interpret their behavior and model non-thermal processes. In particular, these objects are well-established variable stellar sources on the orbital time-scale. The stellar and orbital parameters need to be determined, and this is notably achieved through studies in the optical domain. The combination of observations in the visible domain (including e.g. 3.6-m DOT) with radio measurements using notably GMRT and X-ray observations constitutes thus a promising strategy to investigate particle-accelerating colliding-wind binaries in the forthcoming decade.

DISCOVERY OF X-RAY EMISSION FROM THE FIRST Be/BLACK HOLE SYSTEM

Energy Technology Data Exchange (ETDEWEB)

Munar-Adrover, P.; Paredes, J. M.; Ribó, M. [Departament d' Astronomia i Meteorologia, Institut de Ciències del Cosmos, Universitat de Barcelona, IEEC-UB, Martí i Franquès 1, E-08028 Barcelona (Spain); Iwasawa, K. [ICREA, Institut de Ciències del Cosmos, Universitat de Barcelona, IEEC-UB, Martí i Franquès 1, E-08028 Barcelona (Spain); Zabalza, V. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Casares, J. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain)

2014-05-10

MWC 656 (=HD 215227) was recently discovered to be the first binary system composed of a Be star and a black hole (BH). We observed it with XMM-Newton, and detected a faint X-ray source compatible with the position of the optical star, thus proving it to be the first Be/BH X-ray binary. The spectrum analysis requires a model fit with two components, a blackbody plus a power law, with k{sub B}T=0.07{sub −0.03}{sup +0.04} keV and a photon index Γ = 1.0 ± 0.8, respectively. The non-thermal component dominates above ≅0.8 keV. The obtained total flux is F(0.3-5.5 keV)=(4.6{sub −1.1}{sup +1.3})×10{sup −14} erg cm{sup –2} s{sup –1}. At a distance of 2.6 ± 0.6 kpc the total flux translates into a luminosity L {sub X} = (3.7 ± 1.7) × 10{sup 31} erg s{sup –1}. Considering the estimated range of BH masses to be 3.8-6.9 M {sub ☉}, this luminosity represents (6.7 ± 4.4) × 10{sup –8} L {sub Edd}, which is typical of stellar-mass BHs in quiescence. We discuss the origin of the two spectral components: the thermal component is associated with the hot wind of the Be star, whereas the power-law component is associated with emission from the vicinity of the BH. We also find that the position of MWC 656 in the radio versus X-ray luminosity diagram may be consistent with the radio/X-ray correlation observed in BH low-mass X-ray binaries. This suggests that this correlation might also be valid for BH high-mass X-ray binaries (HMXBs) with X-ray luminosities down to ∼10{sup –8} L {sub Edd}. MWC 656 will allow the accretion processes and the accretion/ejection coupling at very low luminosities for BH HMXBs to be studied.

Bone X-Ray (Radiography)

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Full Text Available ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

Novel X-ray telescopes for wide-field X-ray monitoring

International Nuclear Information System (INIS)

Hudec, R.; Inneman, A.; Pina, L.; Sveda, L.

2005-01-01

We report on fully innovative very wide-field of view X-ray telescopes with high sensitivity as well as large field of view. The prototypes are very promising, allowing the proposals for space projects with very wide-field Lobster-eye X-ray optics to be considered. The novel telescopes will monitor the sky with unprecedented sensitivity and angular resolution of order of 1 arcmin. They are expected to contribute essentially to study and to understand various astrophysical objects such as AGN, SNe, Gamma-ray bursts (GRBs), X-ray flashes (XRFs), galactic binary sources, stars, CVs, X-ray novae, various transient sources, etc. The Lobster optics based X-ray All Sky Monitor is capable to detect around 20 GRBs and 8 XRFs yearly and this will surely significantly contribute to the related science

External and Internal Reconnection in Two Filament-Carrying Magnetic Cavity Solar Eruptions

Science.gov (United States)

Sterling, Alphonse C.; Moore, Ronald L.

2004-01-01

We observe two near-limb solar filament eruptions. one of 2000 February 26 and the other of 2002 January 4. For both we use 195 A Fe XII images from the Extreme-Ultraviolet Imaging Telescope (EIT) and magnetograms from the Michelson Doppler Imager (MDI). both of which are on the Solar and Heliospheric Observatory. (SOHO). For the earlier event we also use soft X-ray telescope (SXT). hard X-ray telescope (HXT). and Bragg Crystal Spectrometer (BCS) data from the Yohkoh satellite. and hard X-ray data from the BATSE experiment on the Compton Gamma Ray Observatory. (CGRO). Both events occur in quadrupolar magnetic regions. and both have coronal features that we infer belong to the same magnetic cavity structures as the filaments. In both cases. the cavity and filament first rise slowly at approx. 10 km/s prior to eruption and then accelerate to approx. 100 km/s during the eruption. although the slow-rise movement for the higher altitude cavity elements is clearer in the later event. We estimate that both filaments and both cavities contain masses of approx. 10(exp14) - 1 0(exp 15) and approx. l0(exp 15) - l0(exp 16) g. respectively. We consider whether two specific magnetic reconnection-based models for eruption onset. the "tether cutting" and the "breakout" models. are consistent with our observations. In the earlier event, soft X-rays from SXT show an intensity increase during the 12 minute interval over which fast eruption begins. which is consistent with tether- cutting-model predictions. Substantial hard X-ray. however. do not occur until after fast eruption is underway. and so this is a constraint the tether-cutting model must satisfy. During the same 12 minute interval over which fast eruption begins, there are brightenings and topological changes in the corona indicative of high-altitude reconnection early in the eruption. and this is consistent with breakout predictions. In both eruptions. the state of the overlying loops at the time of onset of the fast

Bone X-Ray (Radiography)

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Full Text Available ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

Perfect-crystal x-ray optics to treat x-ray coherence

International Nuclear Information System (INIS)

Yamazaki, Hiroshi; Ishikawa, Tetsuya

2007-01-01

X-ray diffraction of perfect crystals, which serve as x-ray monochromator and collimator, modifies coherence properties of x-ray beams. From the time-dependent Takagi-Taupin equations that x-ray wavefields obey in crystals, the reflected wavefield is formulated as an integral transform of a general incident wavefield with temporal and spatial inhomogeneity. A reformulation of rocking-curve profiles from the field solution of the Takagi-Taupin equations allows experimental evaluation of the mutual coherence function of x-ray beam. The rigorous relationship of the coherence functions between before and after reflection clarifies how the coherence is transferred by a crystal. These results will be beneficial to developers of beamline optics for the next generation synchrotron sources. (author)

Exosat observations of the supernova remnant G109.1-1.0 and the X-ray pulsar 1E 2259+586

International Nuclear Information System (INIS)

Morini, M.; Robba, N.R.; Smith, A.; Van Der Klis, M.

1988-01-01

Exosat observations of the SNR G109.1-1.0 and the X-ray pulsar 1E 2259+586 obtained in December 1984 show a similar spatial distribution of the X-ray emission to that found by the Einstein Observatory, but different spectra for the various source components. A pulsar period of 6.978725 s was found for this epoch. The results indicate that the remnant is in the adiabatic phase, with an age of the order of 10,000 yr, and a SN energy in the range 10 to the 51st-10 to the 52nd ergs. Interpretations for the jet emission as either thermal or nonthermal are considered. 30 references

X-ray scattering in X-ray fluorescence spectra with X-ray tube excitation - Modelling, experiment, and Monte-Carlo simulation

International Nuclear Information System (INIS)

Hodoroaba, V.-D.; Radtke, M.; Vincze, L.; Rackwitz, V.; Reuter, D.

2010-01-01

X-ray scattering may contribute significantly to the spectral background of X-ray fluorescence (XRF) spectra. Based on metrological measurements carried out with a scanning electron microscope (SEM) having attached a well characterised X-ray source (polychromatic X-ray tube) and a calibrated energy dispersive X-ray spectrometer (EDS) the accuracy of a physical model for X-ray scattering is systematically evaluated for representative samples. The knowledge of the X-ray spectrometer efficiency, but also of the spectrometer response functions makes it possible to define a physical spectral background of XRF spectra. Background subtraction relying on purely mathematical procedures is state-of-the-art. The results produced by the analytical model are at least as reliable as those obtained by Monte-Carlo simulations, even without considering the very challenging contribution of multiple scattering. Special attention has been paid to Compton broadening. Relevant applications of the implementation of the analytical model presented in this paper are the prediction of the limits of detection for particular cases or the determination of the transmission of X-ray polycapillary lenses.

X-Ray Scattering Applications Using Pulsed X-Ray Sources

Energy Technology Data Exchange (ETDEWEB)

Larson, B.C.

1999-05-23

Pulsed x-ray sources have been used in transient structural phenomena investigations for over fifty years; however, until the advent of synchrotrons sources and the development of table-top picosecond lasers, general access to ligh temporal resolution x-ray diffraction was relatively limited. Advances in diffraction techniques, sample excitation schemes, and detector systems, in addition to IncEased access to pulsed sources, have ld tO what is now a diverse and growing array of pulsed-source measurement applications. A survey of time-resolved investigations using pulsed x-ray sources is presented and research opportunities using both present and planned pulsed x-ray sources are discussed.

X-ray diagnostic installation for X-ray tomographic images

International Nuclear Information System (INIS)

Haendle, J.; Sklebitz, H.

1984-01-01

An exemplary embodiment includes at least one x-ray tube for the generation of an x-ray beam, a patient support, an image detector, and a control generator-connected with the x-ray tube and the image detector-for the purpose of moving the x-ray beam, and in opposition thereto, the image field of the image detector. There is connected to the control generator a layer height computer which calculates the enlargement from the geometric data for the tomogram. The image detector has a circuit-connected with the layer height computer-for the purpose of fading-in a marking for the dimensions in the layer plane

X-ray emission spectroscopy. X-ray fluorescence

International Nuclear Information System (INIS)

Despujols, J.

1992-01-01

Principles of X-ray emission spectrometry are first recalled, then wave-length dispersive and energy dispersive X-ray fluorescence spectrometer are described. They are essentially designed for qualitative and quantitative analysis of elements (Z>10). Sample preparation, calibration, corrections, interferences, accuracy are reviewed. Examples of use in different industries are given. (71 refs.)

DISCOVERY OF X-RAY EMISSION FROM THE GALACTIC SUPERNOVA REMNANT G32.8-0.1 WITH SUZAKU

Energy Technology Data Exchange (ETDEWEB)

Bamba, Aya; Sawada, Makoto [Department of Physics and Mathematics, Aoyama Gakuin University 5-10-1 Fuchinobe Chuo-ku, Sagamihara, Kanagawa 252-5258 (Japan); Terada, Yukikatsu [Department of Physics, Science, Saitama University, Sakura, Saitama 338-8570 (Japan); Hewitt, John; Petre, Robert; Angelini, Lorella [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Safi-Harb, Samar [Department of Physics and Astronomy, University of Manitoba, Winnipeg MB R3T 2N2 (Canada); Zhou, Ping [Department of Astronomy, Nanjing University, Nanjing 210093 (China); Bocchino, Fabrizio [INAF—Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134, Palermo (Italy)

2016-02-10

We present the first dedicated X-ray study of the supernova remnant (SNR) G32.8−0.1 (Kes 78) with Suzaku. X-ray emission from the whole SNR shell has been detected for the first time. The X-ray morphology is well correlated with the emission from the radio shell, while anti-correlated with the molecular cloud found in the SNR field. The X-ray spectrum shows not only conventional low-temperature (kT ∼ 0.6 keV) thermal emission in a non-equilibrium ionization state, but also a very high-temperature (kT ∼ 3.4 keV) component with a very low ionization timescale (∼2.7 × 10{sup 9} cm{sup −3} s), or a hard nonthermal component with a photon index Γ ∼ 2.3. The average density of the low-temperature plasma is rather low, of the order of 10{sup −3}–10{sup −2} cm{sup −3}, implying that this SNR is expanding into a low-density cavity. We discuss the X-ray emission of the SNR, also detected in TeV with H.E.S.S., together with multi-wavelength studies of the remnant and other gamma-ray emitting SNRs, such as W28 and RCW 86. Analysis of a time-variable source, 2XMM J185114.3−000004, found in the northern part of the SNR, is also reported for the first time. Rapid time variability and a heavily absorbed hard-X-ray spectrum suggest that this source could be a new supergiant fast X-ray transient.

Providing x-rays

International Nuclear Information System (INIS)

Mallozzi, P.J.; Epstein, H.M.

1985-01-01

This invention provides an apparatus for providing x-rays to an object that may be in an ordinary environment such as air at approximately atmospheric pressure. The apparatus comprises: means (typically a laser beam) for directing energy onto a target to produce x-rays of a selected spectrum and intensity at the target; a fluid-tight enclosure around the target; means for maintaining the pressure in the first enclosure substantially below atmospheric pressure; a fluid-tight second enclosure adjoining the first enclosure, the common wall portion having an opening large enough to permit x-rays to pass through but small enough to allow the pressure reducing means to evacuate gas from the first enclosure at least as fast as it enters through the opening; the second enclosure filled with a gas that is highly transparent to x-rays; the wall of the second enclosure to which the x-rays travel having a portion that is highly transparent to x-rays (usually a beryllium or plastic foil), so that the object to which the x-rays are to be provided may be located outside the second enclosure and adjacent thereto and thus receive the x-rays substantially unimpeded by air or other intervening matter. The apparatus is particularly suited to obtaining EXAFS (extended x-ray fine structure spectroscopy) data on a material

X-ray detector for a panoramic X-ray unit

Energy Technology Data Exchange (ETDEWEB)

Cowell, D; Ensslin, F H

1976-01-15

The discovery deals with an X-ray detector suitable for the controlling of panoramic X-ray systems. It consists of a fluorescent image screen and a semiconductor photo cell. The output signal of the detector is proportional to the intensity of the X-radiation and the response time is large enough to follow the change of amplitude of the contours of the modulated X radiation. The detector with band-pass filter regulates, via a control system, the moving rate of the X-ray source and of the film opposite it in dependence of the intensity, so that a uniform exposure is ensured.

X-ray imaging with compound refractive lens and microfocus X-ray tube

OpenAIRE

Pina, Ladislav; Dudchik, Yury; Jelinek, Vaclav; Sveda, Libor; Marsik, Jiri; Horvath, Martin; Petr, Ondrej

2008-01-01

Compound refractive lenses (CRL), consisting of a lot number in-line concave microlenses made of low-Z material were studied. Lenses with focal length 109 mm and 41 mm for 8-keV X-rays, microfocus X-ray tube and X-ray CCD camera were used in experiments. Obtained images show intensity distribution of magnified microfocus X-ray source focal spot. Within the experiments, one lens was also used as an objective lens of the X-ray microscope, where the copper anode X-ray microfocus tube served as a...

Abdominal x-ray

Science.gov (United States)

Abdominal film; X-ray - abdomen; Flat plate; KUB x-ray ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

X-ray spectroscopy and X-ray crystallography of metalloenzymes at XFELs

International Nuclear Information System (INIS)

Yano, Junko

2016-01-01

The ultra-bright femtosecond X-ray pulses provided by X-ray Free Electron Lasers (XFELs) open capabilities for studying the structure and dynamics of a wide variety of biological and inorganic systems beyond what is possible at synchrotron sources. Although the structure and chemistry at the catalytic sites have been studied intensively in both biological and inorganic systems, a full understanding of the atomic-scale chemistry requires new approaches beyond the steady state X-ray crystallography and X-ray spectroscopy at cryogenic temperatures. Following the dynamic changes in the geometric and electronic structure at ambient conditions, while overcoming X-ray damage to the redox active catalytic center, is key for deriving reaction mechanisms. Such studies become possible by using the intense and ultra-short femtosecond X-ray pulses from an XFEL, where sample is probed before it is damaged. We have developed methodology for simultaneously collecting crystallography data and X-ray emission spectra, using an energy dispersive spectrometer at ambient conditions. In addition, we have developed a way to collect metal L-edge data of dilute samples using soft X-rays at XFELs. The advantages and challenges of these methods will be described in this review. (author)

ON THE ROLE AND ORIGIN OF NONTHERMAL ELECTRONS IN HOT ACCRETION FLOWS

Energy Technology Data Exchange (ETDEWEB)

Niedźwiecki, Andrzej; Stȩpnik, Agnieszka [Department of Astrophysics, University of Łódź, Pomorska 149/153, 90-236 Łódź (Poland); Xie, Fu-Guo, E-mail: niedzwiecki@uni.lodz.pl, E-mail: agajer@o2.pl, E-mail: fgxie@shao.ac.cn [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China)

2015-02-01

We study the X-ray spectra of tenuous, two-temperature accretion flows using a model involving an exact, Monte Carlo computation of the global Comptonization effect as well as a general relativistic description of both the flow structure and radiative processes. In our previous work, we found that in flows surrounding supermassive black holes, thermal synchrotron radiation is not capable of providing a sufficient seed photon flux to explain the X-ray spectral indices as well as the cut-off energies measured in several best-studied active galactic nuclei (AGNs). In this work, we complete the model by including seed photons provided by nonthermal synchrotron radiation and we find that it allows us to reconcile the hot flow model with the AGN data. We take into account two possible sources of nonthermal electrons. First, we consider e {sup ±} produced by charged-pion decay, which should always be present in the innermost part of a two-temperature flow due to proton-proton interactions. We find that for a weak heating of thermal electrons (small δ) the synchrotron emission of pion-decay e {sup ±} is much stronger than the thermal synchrotron emission in the considered range of bolometric luminosities, L ∼ (10{sup –4}-10{sup –2}) L {sub Edd}. The small-δ model including hadronic effects, in general, agrees with the AGN data, except for the case of a slowly rotating black hole and a thermal distribution of protons. For large δ, the pion-decay e {sup ±} have a negligible effect and, in this model, we consider nonthermal electrons produced by direct acceleration. We find an approximate agreement with the AGN data for the fraction of the heating power of electrons, which is used for the nonthermal acceleration η ∼ 0.1. However, for constant η and δ, the model predicts a positive correlation of the X-ray spectral index with the Eddington ratio, and hence a fine tuning of η and/or δ with the accretion rate is required to explain the negative correlation

Chest X-Ray

Medline Plus

Full Text Available ... talk with you about chest radiography also known as chest x-rays. Chest x-rays are the ... treatment for a variety of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray ...

Modern X-ray spectroscopy 3. X-ray fluorescence holography

International Nuclear Information System (INIS)

Hayashi, Kouichi

2008-01-01

X-ray fluorescence holography (XFH) provides three dimensional atomic images around specified elements. The XFH uses atoms as a wave source or monitor of interference field within a crystal sample, and therefore it can record both intensity and phase of scattered X-rays. Its current performance makes it possible to apply to ultra thin film, impurity and quasicrystal. In this article, I show the theory including solutions for twin image problem, advanced measuring system, data processing for reconstruction of the atomic images and for obtaining accurate atomic positions, applications using resonant X-ray scattering and X-ray excited optical luminescence, and an example of XFH result on the local structure around copper in silicon steal. (author)

X-ray holography: X-ray interactions and their effects

International Nuclear Information System (INIS)

London, R.A.; Trebes, J.E.; Rosen, M.D.

1988-01-01

The authors summarize a theoretical study of the interactions of x-rays with a biological sample during the creation of a hologram. The choice of an optimal wavelength for x-ray holography is discussed, based on a description of scattering by objects within an aqueous environment. The problem of the motion resulting from the absorption of x-rays during a short exposure is described. The possibility of using very short exposures in order to capture the image before motion can compromise the resolution is explored. The impact of these calculation on the question of the feasibility of using an x-ray laser for holography of biological structures is discussed. 12 refs., 2 figs

Filamented plasmas in laser ablation of solids

Czech Academy of Sciences Publication Activity Database

Davies, J.R.; Fajardo, M.; Kozlová, Michaela; Mocek, Tomáš; Polan, Jiří; Rus, Bedřich

2009-01-01

Roč. 51, č. 3 (2009), 035013/1-035013/12 ISSN 0741-3335 EU Projects: European Commission(XE) 12843 - TUIXS Grant - others:FCT(PT) POCI/FIS/59563/2004 Institutional research plan: CEZ:AV0Z10100523 Keywords : magneto-hydrodynamic modelling * perturbation * filaments * x-ray * plasma Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.409, year: 2009

Development of confocal micro X-ray fluorescence instrument using two X-ray beams

International Nuclear Information System (INIS)

Tsuji, Kouichi; Nakano, Kazuhiko; Ding Xunliang

2007-01-01

A new confocal micro X-ray fluorescence instrument was developed. This instrument has two independent micro X-ray tubes with Mo targets. A full polycapillary X-ray lens was attached to each X-ray tube. Another half polycapillary lens was attached to a silicon drift X-ray detector (SDD). The focal spots of the three lenses were adjusted to a common position. The effects of the excitation of two X-ray beams were investigated. The instrument enabled highly sensitive three-dimensional X-ray fluorescence analysis. We confirmed that the X-ray fluorescence intensity from the sample increased by applying the two independent X-ray tubes in confocal configuration. Elemental depth profiling of black wheat was demonstrated with the result that each element in the surface coat of a wheat grain showed unique distribution

Modern X-ray difraction. X-ray diffractometry for material scientists, physicists, and chemicists

International Nuclear Information System (INIS)

Spiess, L.; Schwarzer, R.; Behnken, H.; Teichert, G.

2005-01-01

The book yields a comprehensive survey over the applications of X-ray diffraction in fields like material techniques, metallurgy, electrotechniques, machine engineering, as well as micro- and nanotechniques. The necessary fundamental knowledge on X-ray diffraction are mediated foundedly and illustratively. Thereby new techniques and evaluation procedures are presented as well as well known methods. The content: Production and properties of X radiation, diffraction of X radiation, hardware for X-ray diffraction, methods of X-ray diffraction, lattice-constant determination, phase analysis, X-ray profile analysis, crystal structure analysis, X-ray radiographic stress analysis, X-ray radiographic texture analysis, crystal orientation determination, pecularities at thin films, small angle scattering

X-Ray Exam: Pelvis

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español X-Ray Exam: Pelvis KidsHealth / For Parents / X-Ray Exam: ... Ray Exam: Hip Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

X-ray scattering measurements from thin-foil x-ray mirrors

DEFF Research Database (Denmark)

Christensen, Finn Erland; BYRNAK, BP; Hornstrup, Allan

1992-01-01

Thin foil X-ray mirrors are to be used as the reflecting elements in the telescopes of the X-ray satellites Spectrum-X-Gamma (SRG) and ASTRO-D. High resolution X-ray scattering measurements from the Au coated and dip-lacquered Al foils are presented. These were obtained from SRG mirrors positioned...... in a test quadrant of the telescope structure and from ASTRO-D foils held in a simple fixture. The X-ray data is compared with laser data and other surface structure data such as STM, atomic force microscopy (AFM), TEM, and electron micrography. The data obtained at Cu K-alpha(1), (8.05 keV) from all...

X-ray examination apparatus

NARCIS (Netherlands)

2000-01-01

The invention relates to an X-ray apparatus which includes an adjustable X-ray filter. In order to adjust an intensity profile of the X-ray beam, an X-ray absorbing liquid is transported to filter elements of the X-ray filter. Such transport is susceptible to gravitational forces which lead to an

Development of x-ray laminography under an x-ray microscopic condition

International Nuclear Information System (INIS)

Hoshino, Masato; Uesugi, Kentaro; Takeuchi, Akihisa; Suzuki, Yoshio; Yagi, Naoto

2011-01-01

An x-ray laminography system under an x-ray microscopic condition was developed to obtain a three-dimensional structure of laterally-extended planar objects which were difficult to observe by x-ray tomography. An x-ray laminography technique was introduced to an x-ray transmission microscope with zone plate optics. Three prototype sample holders were evaluated for x-ray imaging laminography. Layered copper grid sheets were imaged as a laminated sample. Diatomite powder on a silicon nitride membrane was measured to confirm the applicability of this method to non-planar micro-specimens placed on the membrane. The three-dimensional information of diatom shells on the membrane was obtained at a spatial resolution of sub-micron. Images of biological cells on the membrane were also obtained by using a Zernike phase contrast technique.

Chest X-Ray

Medline Plus

Full Text Available ... by Image/Video Gallery Your Radiologist Explains Chest X-ray Transcript Welcome to Radiology Info dot org! Hello, ... you about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed ...

Microfocussing of synchrotron X-rays using X-ray refractive lens

Indian Academy of Sciences (India)

X-ray lenses are fabricated in polymethyl methacrylate using deep X-ray lithography beamline of Indus-2. The focussing performance of these lenses is evaluated using Indus-2 and Diamond Light Source Ltd. The process steps for the fabrication of X-ray lenses and microfocussing at 10 keV at moderate and low emittance ...

THE LOCATION OF NON-THERMAL VELOCITY IN THE EARLY PHASES OF LARGE FLARES—REVEALING PRE-ERUPTION FLUX ROPES

International Nuclear Information System (INIS)

Harra, Louise K.; Matthews, Sarah; Culhane, J. L.; Cheung, Mark C. M.; Kontar, Eduard P.; Hara, Hirohisa

2013-01-01

Non-thermal velocity measurements of the solar atmosphere, particularly from UV and X-ray emission lines have demonstrated over the decades that this parameter is important in understanding the triggering of solar flares. Enhancements have often been observed before intensity enhancements are seen. However, until the launch of Hinode, it has been difficult to determine the spatial location of the enhancements to better understand the source region. The Hinode EUV Imaging Spectrometer has the spectral and spatial resolution to allow us to probe the early stages of flares in detail. We analyze four events, all of which are GOES M- or X-classification flares, and all are located toward the limb for ease of flare geometry interpretation. Three of the flares were eruptive and one was confined. In all events, pre-flare enhancement in non-thermal velocity at the base of the active region and its surroundings has been found. These enhancements seem to be consistent with the footpoints of the dimming regions, and hence may be highlighting the activation of a coronal flux rope for the three eruptive events. In addition, pre-flare enhancements in non-thermal velocity were found above the looptops for the three eruptive events

X-ray detector array

International Nuclear Information System (INIS)

Houston, J.M.

1980-01-01

The object of the invention (an ionization chamber X-ray detector array for use with high speed computerised tomographic imaging apparatus) is to reduce the time required to produce a tomographic image. The detector array described determines the distribution of X-ray intensities in one or more flat, coplanar X-ray beams. It comprises three flat anode sheets parallel to the X-ray beam, a plurality of rod-like cathodes between the anodes, a detector gas between the electrodes and a means for applying a potential between the electrodes. Each of the X-ray sources is collimated to give a narrow, planar section of X-ray photons. Sets of X-ray sources in the array are pulsed simultaneously to obtain X-ray transmission data for tomographic image reconstruction. (U.K.)

Studies of solar flares: Homology and X-ray line broadening

Science.gov (United States)

Ranns, Neale David Raymond

This thesis starts with an introduction to the solar atmosphere and the physics that governs its behaviour. The formation processes of spectral lines are presented followed by an explanation of employed plasma diagnostic techniques and line broadening mechanisms. The current understanding on some principle concepts of flare physics are reviewed and the topics of flare homology and non-thermal line broadening are introduced. The many solar satellites and instrumentation that were utilised during this thesis are described. Analysis techniques for some instruments are also presented. A series of solar flares that conform to the literature definition for homologous flares are examined. The apparent homology is shown to be caused by emerging flux rather than continual stressing of a single, or group of, magnetic structure's. The implications for flare homology are discussed. The analysis of a solar flare with a rise and peak in the observed non-thermal X-ray line broadening (Vnt) is then performed. The location of the hot plasma within the flare area is determined and consequently the source of Vnt is located to be within and above the flare loops. The flare footpoints are therefore discarded as a possible source location. Viable source locations are discussed with a view to determining the dominant mechanism for the generation of line broadening. The timing relationships between the hard X-ray (HXR) flux and Vnt in many solar flares are then examined. I show that there is a causal relationship between these two parameters and that the HXR rise time is related to the time delay between the maxima of HXR flux and Vnt. The temporal evolution of Vnt is shown to be dependent upon the shape of the HXR burst. The implications of these results are discussed in terms of determining the line broadening mechanism and the limitations of the data. A summary of the results in this thesis is then presented together with suggestions for future research.

DISCOVERY OF C IV EMISSION FILAMENTS IN M87

International Nuclear Information System (INIS)

Sparks, W. B.; Pringle, J. E.; Cracraft, M.; Donahue, M.; Voit, M.; Carswell, R.; Martin, R. G.

2009-01-01

Gas at intermediate temperatures between the hot X-ray-emitting coronal gas in galaxies at the centers of galaxy clusters and the much cooler optical line emitting filaments yields information on transport processes and plausible scenarios for the relationship between X-ray cool cores and other galactic phenomena such as mergers or the onset of an active galactic nucleus. Hitherto, detection of intermediate temperature gas has proven elusive. Here, we present FUV imaging of the 'low excitation' emission filaments of M87 and show strong evidence for the presence of C IV 1549 A emission which arises in gas at temperature ∼10 5 K co-located with Hα+[N II] emission from cooler ∼10 4 K gas. We infer that the hot and cool phases are in thermal communication, and show that quantitatively the emission strength is consistent with thermal conduction, which in turn may account for many of the observed characteristics of cool-core galaxy clusters.

Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

Directory of Open Access Journals (Sweden)

L. Miaja-Avila

2015-03-01

Full Text Available We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ∼106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.

Mechanical response of melt-spun amorphous filaments

International Nuclear Information System (INIS)

Leal, A A; Reifler, F A; Hufenus, R; Mohanty, G; Michler, J

2014-01-01

High-speed melt spinning of a cyclo-olefin polymer (COP) and a copolyamide (CoPA) have been performed. Differential scanning calorimetry curves of the resulting monofilaments show that they remain in an amorphous state even after hot drawing. Wide angle x-ray diffraction patterns of undrawn and drawn COP filaments show that although the material remains in an amorphous state, a degree of orientation is induced in the polymer after drawing. The amorphous filaments show an enhanced bending recovery with respect to different semi-crystalline monofilaments commercially available. However, single fiber axial compressive testing indicates that the amorphous filaments exhibit a compressive modulus value which is 50% lower than what is observed for a reference semi-crystalline PET filament. Analysis of the compressive strains applied by the bending recovery test indicates that while the maximum applied strains remain well within the region of elastic deformation of the amorphous materials, the threshold between elastic and plastic deformation is reached for the semi-crystalline materials. (paper)

X-ray instrumentation in astronomy

International Nuclear Information System (INIS)

Cuhlane, J.L.

1985-01-01

This book presents the proceedings of a conference devoted to x-ray instrumentation in astronomy. Special sections are: AXAF X-Ray Optical Systems; Specialized X-Ray Systems; X-Ray Optical Systems I; X-Ray Optical Systems II; Gas Filled X-Ray Detectors II; The NASA Advanced X-Ray Astrophysics Facility; X-Ray and EUV Spectrometers; Microchannel Plates; and Solid State Detectors

Panoramic Dental X-Ray

Science.gov (United States)

... Physician Resources Professions Site Index A-Z Panoramic Dental X-ray Panoramic dental x-ray uses a very small dose of ... x-ray , is a two-dimensional (2-D) dental x-ray examination that captures the entire mouth ...

Chest X-Ray

Medline Plus

Full Text Available ... I’d like to talk with you about chest radiography also known as chest x-rays. Chest x-rays are the most ... far outweighs any risk. For more information about chest x-rays, visit Radiology Info dot org. Thank you for your time! ...

Miniature x-ray point source for alignment and calibration of x-ray optics

International Nuclear Information System (INIS)

Price, R.H.; Boyle, M.J.; Glaros, S.S.

1977-01-01

A miniature x-ray point source of high brightness similar to that of Rovinsky, et al. is described. One version of the x-ray source is used to align the x-ray optics on the Argus and Shiva laser systems. A second version is used to determine the spatial and spectral transmission functions of the x-ray optics. The spatial and spectral characteristics of the x-ray emission from the x-ray point source are described. The physical constraints including size, intensity and thermal limitations, and useful lifetime are discussed. The alignment and calibration techniques for various x-ray optics and detector combinations are described

Subluminous X-ray binaries

NARCIS (Netherlands)

Armas Padilla, M.

2013-01-01

The discovery of the first X-ray binary, Scorpius X-1, by Giacconi et al. (1962), marked the birth of X-ray astronomy. Following that discovery, many additional X-ray sources where found with the first generation of X-ray rockets and observatories (e.g., UHURU and Einstein). The short-timescale

External and Internal Reconnection in Two Filament-Carrying Magnetic-Cavity Solar Eruptions

Science.gov (United States)

Sterling, Alphonse C.; Moore, Ronald L.

2004-01-01

We observe two near-limb solar filament eruptions, one of 2000 February 26 and the other of 2002 January 4. For both we use 195 A Fe XII images from the Extreme-Ultraviolet Imaging Telescope (EIT) and magnetograms from the Michelson Doppler Imager (MDI), both of which are on the Solar and Heliospheric Observatory (SOHO). For the earlier event we also use soft X-ray telescope (SXT), hard X-ray telescope (HXT), and Bragg Crystal Spectrometer (BCS) data from the Yohkoh satellite, and hard X-ray data from the BATSE experiment on the Compton Gamma Ra.v Observatory (CGRO). Both events occur in quadrupolar magnetic regions, and both have coronal features that we infer belong to the same magnetic cavity structures as the filaments. In both cases, the cavity and filament first rise slowly at approx.10 km/s prior to eruption and then accelerate to approx.100 km/s during the eruption, although the slow-rise movement for the higher altitude cavity elements is clearer in the later event. We estimate that both filaments and both cavities contain masses of approx.10(exp 14)-10(exp 15) and approx.10(exp 15)-10(exp 16) g, respectively. We consider whether two specific magnetic reconnection-based models for eruption onset, the "tether cutting" and the "breakout" models, are consistent with our observations. In the earlier event, soft X-rays from SXT show an intensity increase during the 12 minute interval over which fast eruption begins, which is consistent with tether- cutting-model predictions. Substantial hard X-rays, however, do not occur until after fast eruption is underway, and so this is a constraint the tether-cutting model must satisfy. During the same 12 minute interval over which fast eruption begins, there are brightenings and topological changes in the corona indicative of high-altitude reconnection early in the eruption, and this is consistent with breakout predictions. In both eruptions, the state of the overlying loops at the time of onset of the fast-rise phase of

X-Ray Exam: Forearm

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español X-Ray Exam: Forearm KidsHealth / For Parents / X-Ray Exam: ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

X-Ray Exam: Foot

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español X-Ray Exam: Foot KidsHealth / For Parents / X-Ray Exam: ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

X-Ray Exam: Wrist

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español X-Ray Exam: Wrist KidsHealth / For Parents / X-Ray Exam: ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

Thoracic spine x-ray

Science.gov (United States)

Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

X-Ray Exam: Finger

Science.gov (United States)

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Hard alpha-keratin degradation inside a tissue under high flux X-ray synchrotron micro-beam: a multi-scale time-resolved study.

Science.gov (United States)

Leccia, Emilie; Gourrier, Aurélien; Doucet, Jean; Briki, Fatma

2010-04-01

X-rays interact strongly with biological organisms. Synchrotron radiation sources deliver very intense X-ray photon fluxes within micro- or submicro cross-section beams, resulting in doses larger than the MGy. The relevance of synchrotron radiation analyses of biological materials is therefore questionable since such doses, million times higher than the ones used in radiotherapy, can cause huge damages in tissues, with regard to not only DNA, but also proteic and lipid organizations. Very few data concerning the effect of very high X-ray doses in tissues are available in the literature. We present here an analysis of the structural phenomena which occur when the model tissue of human hair is irradiated by a synchrotron X-ray micro-beam. The choice of hair is supported by its hierarchical and partially ordered keratin structure which can be analysed inside the tissue by X-ray diffraction. To assess the damages caused by hard X-ray micro-beams (1 microm(2) cross-section), short exposure time scattering SAXS/WAXS patterns have been recorded at beamline ID13 (ESRF) after various irradiation times. Various modifications of the scattering patterns are observed, they provide fine insight of the radiation damages at various hierarchical levels and also unexpectedly provide information about the stability of the various hierarchical structural levels. It appears that the molecular level, i.e. the alpha helices which are stabilized by hydrogen bonds and the alpha-helical coiled coils which are stabilized by hydrophobic interactions, is more sensitive to radiation than the supramolecular architecture of the keratin filament and the filament packing within the keratin associated proteins matrix, which is stabilized by disulphide bonds. (c) 2009 Elsevier Inc. All rights reserved.

Soft x-ray lasers

International Nuclear Information System (INIS)

Matthews, D.L.; Rosen, M.D.

1988-01-01

One of the elusive dreams of laser physicists has been the development of an x-ray laser. After 25 years of waiting, the x-ray laser has at last entered the scientific scene, although those now in operation are still laboratory prototypes. They produce soft x rays down to about five nanometers. X-ray lasers retain the usual characteristics of their optical counterparts: a very tight beam, spatial and temporal coherence, and extreme brightness. Present x-ray lasers are nearly 100 times brighter that the next most powerful x-ray source in the world: the electron synchrotron. Although Lawrence Livermore National Laboratory (LLNL) is widely known for its hard-x-ray laser program which has potential applications in the Strategic Defense Initiative, the soft x-ray lasers have no direct military applications. These lasers, and the scientific tools that result from their development, may one day have a place in the design and diagnosis of both laser fusion and hard x-ray lasers. The soft x-ray lasers now in operation at the LLNL have shown great promise but are still in the primitive state. Once x-ray lasers become reliable, efficient, and economical, they will have several important applications. Chief among them might be the creation of holograms of microscopic biological structures too small to be investigated with visible light. 5 figs

Frequency filter of seed x-ray by use of x-ray laser medium. Toward the generation of the temporally coherent x-ray laser

International Nuclear Information System (INIS)

Hasegawa, Noboru; Kawachi, Tetsuya; Kishimoto, Maki; Sukegawa, Kouta; Tanaka, Momoko; Ochi, Yoshihiro; Nishikino, Masaharu; Nagashima, Keisuke; Kato, Yoshiaki; Renzhong, Tai

2009-01-01

We evaluate the characteristics of a higher-order harmonics light as a seed X-ray amplified through a laser-produced X-ray amplifier. The narrow spectral bandwidth of the X-ray amplifier works as the frequency filter of the seed X-ray, resulting in that only the temporally coherent X-ray is amplified. Experimental investigation using the 29th-order harmonic light of the Ti:sapphire laser at a wavelength of 26.9 nm together with a neon-like manganese X-ray laser medium shows evident spectral narrowing of the seed X-ray and amplification without serious diffraction effects on the propagation of the amplified X-ray beam. This implies that the present combination is potential to realize temporally coherent X-ray lasers, with an expected duration of approximately 400 fs. (author)

Joint European x-ray monitor (JEM-X): x-ray monitor for ESA's

DEFF Research Database (Denmark)

Schnopper, H.W.; Budtz-Joergensen, C.; Westergaard, Niels Jørgen Stenfeldt

1996-01-01

JEM-X will extend the energy range of the gamma ray instruments on ESA's INTEGRAL mission (SPI, IBIS) to include the x-ray band. JEM-X will provide images with arcminute angular resolution in the 2 - 60 keV band. The baseline photon detection system consists of two identical, high pressure, imagi...

Wide field x-ray telescopes: Detecting x-ray transients/afterglows related to GRBs

International Nuclear Information System (INIS)

Hudec, Rene; Pina, Ladislav; Inneman, Adolf; Gorenstein, Paul

1998-01-01

The recent discovery of X-ray afterglows of GRBs opens the possibility of analyses of GRBs by their X-ray detections. However, imaging X-ray telescopes in current use mostly have limited fields of view. Alternative X-ray optics geometries achieving very large fields of view have been theoretically suggested in the 70's but not constructed and used so far. We review the geometries and basic properties of the wide-field X-ray optical systems based on one- and two-dimensional lobster-eye geometry and suggest technologies for their development and construction. First results of the development of double replicated X-ray reflecting flats for use in one-dimensional X-ray optics of lobster-eye type are presented and discussed. The optimum strategy for locating GRBs upon their X-ray counterparts is also presented and discussed

ON THE ORIGIN OF THE EXTENDED Hα FILAMENTS IN COOLING FLOW CLUSTERS

International Nuclear Information System (INIS)

McDonald, Michael; Veilleux, Sylvain; Mushotzky, Richard; Rupke, David S. N.

2010-01-01

We present a high spatial resolution Hα survey of 23 cooling flow clusters using the Maryland Magellan Tunable Filter, covering 1-2 orders of magnitude in cooling rate, dM/dt, temperature, and entropy. We find that 8/23 (35%) of our clusters have complex, filamentary morphologies at Hα, while an additional 7/23 (30%) have marginally extended or nuclear Hα emission, in general agreement with previous studies of line emission in cooling flow cluster brightest cluster galaxies. A weak correlation between the integrated near-UV luminosity and the Hα luminosity is also found for our complete sample with a large amount of scatter about the expected relation for photoionization by young stars. We detect Hα emission out to the X-ray cooling radius, but no further, in several clusters and find a strong correlation between the Hα luminosity contained in filaments and the X-ray cooling flow rate of the cluster, suggesting that the warm ionized gas is linked to the cooling flow. Furthermore, we detect a strong enhancement in the cooling properties of the intracluster medium (ICM) coincident with the Hα emission, compared to the surrounding ICM at the same radius. While the filaments in a few clusters may be entrained by buoyant radio bubbles, in general, the radially infalling cooling flow model provides a better explanation for the observed trends. The correlation of the Hα and X-ray properties suggests that conduction may be important in keeping the filaments ionized. The thinness of the filaments suggests that magnetic fields are an important part of channeling the gas and shielding it from the surrounding hot ICM.

A Liquid-Cryogen-Free Superconducting Tunnel Junction X-ray Spectrometer for Astrobiology Research at the Synchrotron

International Nuclear Information System (INIS)

Friedrich, S.; Drury, O.B.; Hertrich, T.; Hoehne, J.

2008-01-01

Superconducting tunnel junctions (STJs) are being developed as energy-dispersive soft X-ray detectors, because they combine the high energy resolution of low-temperature detectors with the comparably high count rates of non-thermal devices. We have built a 36-pixel spectrometer based on 200 (micro)m x 200 (micro)m Nb-Al-AlOx-Al-Nb STJs. It offers an energy resolution of ∼10 to 20 eV FWHM in the soft X-ray band below 1 keV, a solid angle coverage (Omega)/4π ∼ 10 -3 , and can be operated at total rates up to ∼10 6 counts/s. For STJ operation by non-expert users, we have built a liquid-cryogen-free spectrometer with a mechanical pulse-tube cryocooler and a two-stage adiabatic demagnetization refrigerator. It is fully automated for cooldown to a base temperature of 3 days between demagnetization cycles for STJ operation at 0.3 K. The STJ spectrometers are used for speciation measurements on dilute samples by fluorescence-detected X-ray absorption spectroscopy, and can achieve sensitivities below 100 ppm. We discuss the spectrometer performance in representative applications on metals in meteorites in the context of geological signatures of biological activity

X rays and condensed matter

International Nuclear Information System (INIS)

Daillant, J.

1997-01-01

After a historical review of the discovery and study of X rays, the various interaction processes between X rays and matter are described: Thomson scattering, Compton scattering, X-photon absorption through photoelectric effect, and magnetic scattering. X ray sources such as the European Synchrotron Radiation Facility (ESRF) are described. The various X-ray applications are presented: imagery such as X tomography, X microscopy, phase contrast; X-ray photoelectron spectroscopy and X-ray absorption spectroscopy; X-ray scattering and diffraction techniques

Extending the methodology of X-ray crystallography to allow X-ray microscopy without X-ray optics

International Nuclear Information System (INIS)

Miao Jianwei; Kirz, Janos; Sayre, David; Charalambous, Pambos

2000-01-01

We demonstrate that the soft X-ray diffraction pattern from a micron-size noncrystalline specimen can be recorded and inverted to form a high-resolution image. The phase problem is overcome by oversampling the diffraction pattern. The image is obtained using an iterative algorithm. The technique provides a method for X-ray microscopy requiring no high-resolution X-ray optical elements or detectors. In the present work, a resolution of approximately 60 nm was obtained, but we believe that considerably higher resolution can be achieved

Dental X-ray apparatus

International Nuclear Information System (INIS)

Weiss, M.E.

1980-01-01

Intra-oral dental X-ray apparatus for panoramic radiography is described in detail. It comprises a tubular target carrier supporting at its distal end a target with an inclined forward face. Image definition is improved by positioning in the path of the X-rays a window of X-ray transmitting ceramic material, e.g. 90% oxide of Be, or Al, 7% Si0 2 . The target carrier forms a probe which can be positioned in the patient's mouth. X-rays are directed forwardly and laterally of the target to an X-ray film positioned externally. The probe is provided with a detachable sleeve having V-form arms of X-ray opaque material which serve to depress the tongue out of the radiation path and also shield the roof of the mouth and other regions of the head from the X-ray pattern. A cylindrical lead shield defines the X-ray beam angle. (author)

X-ray diagnostics for TFTR

International Nuclear Information System (INIS)

von Goeler, S.; Hill, K.W.; Bitter, M.

1982-12-01

A short description of the x-ray diagnostic preparation for the TFTR tokamak is given. The x-ray equipment consists of the limiter x-ray monitoring system, the soft x-ray pulse-height-analysis-system, the soft x-ray imaging system and the x-ray crystal spectrometer. Particular attention is given to the radiation protection of the x-ray systems from the neutron environment

X-ray beam generator

International Nuclear Information System (INIS)

Koller, T.J.; Randmer, J.A.

1977-01-01

A method of minimizing the preferential angular absorption of the divergent beam from an X-ray generator is described. The generator consists of an X-ray shielded housing with an X-ray transmissive window symmetrically placed in radial alignment with a focal spot area on a sloped target surface of an X-ray tube in the housing. The X-ray tube may be of the stationary anode type or of the rotating anode type. (U.K.)

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... ray examination. X-rays usually have no side effects in the typical diagnostic range for this exam. ... x-rays. A Word About Minimizing Radiation Exposure Special care is taken during x-ray examinations to ...

Cellulose/inorganic-composite fibers for producing textile fabrics of high X-ray absorption properties

Energy Technology Data Exchange (ETDEWEB)

Günther, Karoline; Giebing, Christina; Askani, Antonia [FTB, Hochschule Niederrhein – University of Applied Science, Faculty of Textile and Clothing Technology, Webschulstr. 31, 41065 Mönchengladbach (Germany); Leisegang, Tilmann [Saxray GmbH, Maria-Reiche-Str. 1, 01109 Dresden (Germany); Krieg, Marcus [TITK, Thüringisches Institut für Textil- und Kunststoff-Forschung e.V., Breitscheidstraße 97, 07407 Rudolstadt (Germany); Kyosev, Yordan; Weide, Thomas [FTB, Hochschule Niederrhein – University of Applied Science, Faculty of Textile and Clothing Technology, Webschulstr. 31, 41065 Mönchengladbach (Germany); Mahltig, Boris, E-mail: Boris.Mahltig@hs-niederrhein.de [FTB, Hochschule Niederrhein – University of Applied Science, Faculty of Textile and Clothing Technology, Webschulstr. 31, 41065 Mönchengladbach (Germany)

2015-11-01

Common textile materials as cotton or polyester do not possess reliable X-ray absorption properties. This is due to their morphology and chemical composition in particular. Common fibers are built up from organic polymers containing mainly the elements carbon, hydrogen, oxygen and nitrogen. These “light” elements only have low X-ray absorption coefficients. In contrast, inorganic materials composed of “heavy” elements with high atomic numbers, e.g. barium or bismuth, exhibit X-ray absorption coefficients higher by up to two orders of magnitude. To obtain a flexible yarn with high X-ray absorption properties both these materials, the organic polymer and the inorganic X-ray absorber, are combined to an inorganic/organic composite fiber material. Hence, as the organic component cellulose from modified Lyocell-process is used as carrier fiber and blended with inorganic absorber particles of low toxicity and high absorption coefficients, as bariumsulphate, bariumtitanate or bismuthoxide. A content of inorganic absorber particles equally distributed in the whole fiber of up to 20% is achieved. The composite fibers are produced as staple or filament fibers and processed to multifilament or staple fiber yarns. The staple fiber yarns are rotor-spinned to increase the comfort of the subsequent textile material. Several woven fabrics, considering multilayer structure and different warp/weft density, are developed. The energy dependent X-ray shielding properties are determined in dependence on the different yarn compositions, yarn types and structural parameters of the woven fabrics. As a result, a production process of textile materials with comfortable and dedicated X-ray absorption properties is established. It offers a promising opportunity for manufacturing of specialized textiles, working clothes or uniforms applicable for medicine, air craft and security personal, mining as well as for innovative composite materials. - Highlights: • Preparation of cellulosic

Cellulose/inorganic-composite fibers for producing textile fabrics of high X-ray absorption properties

International Nuclear Information System (INIS)

Günther, Karoline; Giebing, Christina; Askani, Antonia; Leisegang, Tilmann; Krieg, Marcus; Kyosev, Yordan; Weide, Thomas; Mahltig, Boris

2015-01-01

Common textile materials as cotton or polyester do not possess reliable X-ray absorption properties. This is due to their morphology and chemical composition in particular. Common fibers are built up from organic polymers containing mainly the elements carbon, hydrogen, oxygen and nitrogen. These “light” elements only have low X-ray absorption coefficients. In contrast, inorganic materials composed of “heavy” elements with high atomic numbers, e.g. barium or bismuth, exhibit X-ray absorption coefficients higher by up to two orders of magnitude. To obtain a flexible yarn with high X-ray absorption properties both these materials, the organic polymer and the inorganic X-ray absorber, are combined to an inorganic/organic composite fiber material. Hence, as the organic component cellulose from modified Lyocell-process is used as carrier fiber and blended with inorganic absorber particles of low toxicity and high absorption coefficients, as bariumsulphate, bariumtitanate or bismuthoxide. A content of inorganic absorber particles equally distributed in the whole fiber of up to 20% is achieved. The composite fibers are produced as staple or filament fibers and processed to multifilament or staple fiber yarns. The staple fiber yarns are rotor-spinned to increase the comfort of the subsequent textile material. Several woven fabrics, considering multilayer structure and different warp/weft density, are developed. The energy dependent X-ray shielding properties are determined in dependence on the different yarn compositions, yarn types and structural parameters of the woven fabrics. As a result, a production process of textile materials with comfortable and dedicated X-ray absorption properties is established. It offers a promising opportunity for manufacturing of specialized textiles, working clothes or uniforms applicable for medicine, air craft and security personal, mining as well as for innovative composite materials. - Highlights: • Preparation of cellulosic

Semiconductor X-ray detectors

CERN Document Server

Lowe, Barrie Glyn

2014-01-01

Identifying and measuring the elemental x-rays released when materials are examined with particles (electrons, protons, alpha particles, etc.) or photons (x-rays and gamma rays) is still considered to be the primary analytical technique for routine and non-destructive materials analysis. The Lithium Drifted Silicon (Si(Li)) X-Ray Detector, with its good resolution and peak to background, pioneered this type of analysis on electron microscopes, x-ray fluorescence instruments, and radioactive source- and accelerator-based excitation systems. Although rapid progress in Silicon Drift Detectors (SDDs), Charge Coupled Devices (CCDs), and Compound Semiconductor Detectors, including renewed interest in alternative materials such as CdZnTe and diamond, has made the Si(Li) X-Ray Detector nearly obsolete, the device serves as a useful benchmark and still is used in special instances where its large, sensitive depth is essential. Semiconductor X-Ray Detectors focuses on the history and development of Si(Li) X-Ray Detect...

A survey of chest medical X-ray doses

International Nuclear Information System (INIS)

Lomba, M.; Conha, P.G. da; Almeida, C.E. de

1996-01-01

The medical X-ray exposures due to radiological examinations are responsible for the largest contribution to the population collective dose as result of the normal use of artificial sources of radiation. The relative impact of the medical exposures to the total dose received by the population from all kinds of radiation sources varies from country to country and in some cases within the same country. The dose variations observed for a specific type of examination are in general associated to several factors i.e. the type of film-ecran combination, the choice of the appropriate physical parameters of the X-ray generator (Kvp, filament current, exposure time) and finally to the film processing conditions. At the present moment the data available in Brazil are scarce and scanty to allow a complete analyzis of this question so needed by the health authorities to justify the implementation of a quality assurance and dose reduction programs. In addition, it is desirable to establish a cost effective operation based on simple administrative concepts in order to reduce the number of films retake, then increasing the life expectancy of the equipment and the number of radiological procedures. The aim of this work was to assess the typical doses of an PA and LAT chest wall X-ray examinations in five different public hospitals (a University Hospital, a Cancer Hospital, a Navy Hospital, an Emergency Hospital and a State General Hospital), as representative of the city of Rio de Janeiro, and compare the results with the international data and recommendations available. (author)

Non-thermal desorption/ablation of molecular solids induced by ultra-short soft x-ray pulses

Czech Academy of Sciences Publication Activity Database

Chalupský, Jaromír; Juha, Libor; Hájková, Věra; Cihelka, Jaroslav; Vyšín, Luděk; Gautier, J.; Hajdu, J.; Hau-Riege, S.P.; Jurek, M.; Krzywinski, J.; London, R.A.; Papalazarou, E.; Pelka, J. B.; Rey, G.; Sebban, S.; Sobierajski, R.; Stojanovic, N.; Tiedtke, K.; Toleikis, S.; Tschentscher, T.; Valentin, C.; Wabnitz, H.; Zeitoun, P.

2009-01-01

Roč. 17, č. 1 (2009), s. 208-217 ISSN 1094-4087 R&D Projects: GA AV ČR KAN300100702; GA MŠk LC510; GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR IAA400100701 Grant - others:EU FP6 NEST-Adventure(XE) 012843 Institutional research plan: CEZ:AV0Z10100523 Keywords : x-ray laser * high-order harmonics * free-electron laser * desorption * ablation * organic polymer Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.278, year: 2009

X-ray apparatus

International Nuclear Information System (INIS)

Grady, J.K.

1985-01-01

X-ray apparatus is described which has a shutter between the X-ray source and the patient. The shutter controls the level of radiation to which the patient is exposed instead of merely discontinuing the electric power supplied to the source. When the shutter is opened a radiation sensor senses the level of X-radiation. When a preset quantity of X-radiation has been measured an exposure control closes the shutter. Instead of using the radiation sensor, the integrated power supplied to the anode of the X-ray source may be measured. (author)

Method for spatially modulating X-ray pulses using MEMS-based X-ray optics

Science.gov (United States)

Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

2015-03-10

A method and apparatus are provided for spatially modulating X-rays or X-ray pulses using microelectromechanical systems (MEMS) based X-ray optics. A torsionally-oscillating MEMS micromirror and a method of leveraging the grazing-angle reflection property are provided to modulate X-ray pulses with a high-degree of controllability.

Optical and X-ray studies of Compact X-ray Binaries in NGC 5904

Science.gov (United States)

Bhalotia, Vanshree; Beck-Winchatz, Bernhard

2018-06-01

Due to their high stellar densities, globular cluster systems trigger various dynamical interactions, such as the formation of compact X-ray binaries. Stellar collisional frequencies have been correlated to the number of X-ray sources detected in various clusters and we hope to measure this correlation for NGC 5904. Optical fluxes of sources from archival HST images of NGC 5904 have been measured using a DOLPHOT PSF photometry in the UV, optical and near-infrared. We developed a data analysis pipeline to process the fluxes of tens of thousands of objects using awk, python and DOLPHOT. We plot color magnitude diagrams in different photometric bands in order to identify outliers that could be X-ray binaries, since they do not evolve the same way as singular stars. Aligning previously measured astrometric data for X-ray sources in NGC 5904 from Chandra with archival astrometric data from HST will filter out the outlier objects that are not X-ray producing, and provide a sample of compact binary systems that are responsible for X-ray emission in NGC 5904. Furthermore, previously measured X-ray fluxes of NGC 5904 from Chandra have also been used to measure the X-ray to optical flux ratio and identify the types of compact X-ray binaries responsible for the X-ray emissions in NGC 5904. We gratefully acknowledge the support from the Illinois Space Grant Consortium.

EIT and SXT Observations of a Quiet Region Filament Ejection: First Eruption, Then Reconnection

Science.gov (United States)

Sterling, Alphonse C.; Moore, Ronald L.; Thompson, Barbara J.; Six, N. Frank (Technical Monitor)

2001-01-01

We observe a slow-onset quiet-region filament eruption with the EUV Imaging Telescope (EIT) on SOHO, and the Soft X-ray Telescope (SXT) on Yohkoh. This event occurred on 1999 April 18, and was likely the origin of a coronal mass ejection (CME) detected by SOHO at 08:30 UT on that day. In EIT, one-half of the filament shows two stages of evolution: Stage I is a slow, roughly constant upward movement at approx. 1 km per second lasting approximately 6.5 hours, and Stage 2 is a rapid upward eruption at approximately 16 kilometers per second occurring just before the filament disappears into interplanetary space. The other half of the filament shows little motion along the line-of-sight during the time of Stage 1, but erupts along with the rest of the filament during Stage 2. There is no obvious emission from the filament in SXT until Stage 2; at that time an arcade of EUV and soft X-ray loops forms first at the central location of the filament, and then expands outward along the length of the filament channel. A plot of EUV intensity versus time of the central portion of the filament (where the postflare loops initially form) shows a flat profile during Stage 1, and a rapid upturn after the start of Stage 2. This lightcurve is delayed from what would be expected if "tether-cutting" reconnection in the core of the erupting region were responsible for the initiation of the eruption. Rather, these observations suggest that a loss of stability of the magnetic field holding the filament initiates the eruption, with reconnection in the core region occurring only as a byproduct.

EIT And SXT Observations of a Quiet-Region Filament Ejection: First Eruption, Then Reconnection

Science.gov (United States)

Sterling, Alphonse C.; Moore, Ronald L.; Thompson, Barbara J.

2001-01-01

We observe a slow-onset quiet-region filament eruption with the Extreme Ultraviolet Imaging Telescope (EIT) on the Solar Heliospheric Observatory (SOHO) and the Soft X-ray Telescope (SXT) on Yohkoh. This event occurred on 1999 April 18 and was likely the origin of a coronal mass ejection detected by SOHO at 08:30 UT on that day. In the EIT observation, one-half of the filament shows two stages of evolution: stage 1 is a slow, roughly constant upward movement at approximately 1 km/s lasting approximately 0.5 hr, and stage 2 is a rapid upward eruption at approximately 16 km/s occurring just before the filament disappears into interplanetary space. The other half of the filament shows little motion along the line of sight during the time of stage 1 but erupts along with the rest of the filament during stage 2. There is no obvious emission from the filament in the SXT observation until stage 2; at that time, an arcade of EUV and soft X-ray loops forms first at the central location of the filament and then expands outward along the length of the filament channel. A plot of EUV intensity versus time of the central portion of the filament (where the postflare loops initially form) shows a flat profile during stage 1 and a rapid upturn after the start of stage 2. This light curve is delayed from what would be expected if 'tether-cutting' reconnection in the core of the erupting region were responsible for the initiation of the eruption. Rather, these observations suggest that a loss of stability of the magnetic field holding the filament initiates the eruption, with reconnection in the core region occurring only as a by-product.

CCD-based X-ray detectors for X-ray diffraction studies

International Nuclear Information System (INIS)

Ito, K.; Amemiya, Y.

1999-01-01

CCD-based X-ray detectors are getting to be used for X-ray diffraction studies especially in the studies where real time (automated) measurements and time-resolved measurements are required. Principles and designs of two typical types of CCD-based detectors are described; one is ths system in which x-ray image intensifiers are coupled to maximize the detective quantum efficiency for time-resolved measurements, and the other is the system in which tapered optical fibers are coupled for the reduction of the image into the CCD, which is optimized for automated measurements for protein crystallography. These CCD-based X-ray detectors have an image distortion and non-uniformity of response to be corrected by software. Correction schemes which we have developed are also described. (author)

Simulation of transmitted X-rays in a polycapillary X-ray lens

Energy Technology Data Exchange (ETDEWEB)

Peng, Shiqi [The Key Laboratory of Beam Technology and Material Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Liu, Zhiguo, E-mail: liuzhiguo512@126.com [The Key Laboratory of Beam Technology and Material Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Sun, Tianxi; Wang, Kai; Yi, Longtao; Yang, Kui; Chen, Man; Wang, Jinbang [The Key Laboratory of Beam Technology and Material Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

2015-09-21

The geometrical description of capillary systems adjusted for the controlled guiding of X-rays and the basic theory of the transmission of X-rays are presented. A method of numerical calculation, based on Ray-Tracing theory, is developed to simulate the transmission efficiency of an X-ray parallel lens and the shape and size of the light spot gain from it. The simulation results for two half-lenses are in good agreement with the experimental results.

Microfocussing of synchrotron X-rays using X-ray refractive lens developed at Indus-2 deep X-ray lithography beamline

International Nuclear Information System (INIS)

Dhamgaye, V.P.; Tiwari, M.K.; Lodha, G.S.; Sawhney, K.J.S.

2014-01-01

X-ray lenses are fabricated in polymethyl methacrylate using deep X-ray lithography beamline of Indus-2. The focussing performance of these lenses is evaluated using Indus-2 and Diamond Light Source Ltd. The process steps for the fabrication of X-ray lenses and microfocussing at 10 keV at moderate and low emittance sources are compared. (author)

On the association of magnetic clouds with disappearing filaments

International Nuclear Information System (INIS)

Wilson, R.M.; Hildner, E.

1986-01-01

We present evidence that an interplanetary magnetic cloud preceding an interaction region, observed at earth January 24, 1974, is associated with the eruptive filament or disparition brusque (DB) near central meridian on January 18. The DB also was associated with a long-decay soft X ray transient (LDE) and a long-duration gradual-rise-and-fall (GRF) radio burst. To assess whether magnetic clouds are generally associated with DBs, we present results from statistical testing of the relation of 33 magnetic clouds (and 33 control samples without magnetic clouds) to disappearing filaments near central meridian (approx. 99% confidence. There is a suggestion that clouds following shocks, probably launched at times of solar flares, are not as strongly associated with disappearing filaments as are clouds launched less violently

X pinch a point x-ray source

International Nuclear Information System (INIS)

Garg, A.B.; Rout, R.K.; Shyam, A.; Srinivasan, M.

1993-01-01

X ray emission from an X pinch, a point x-ray source has been studied using a pin-hole camera by a 30 kV, 7.2 μ F capacitor bank. The wires of different material like W, Mo, Cu, S.S.(stainless steel) and Ti were used. Molybdenum pinch gives the most intense x-rays and stainless steel gives the minimum intensity x-rays for same bank energy (∼ 3.2 kJ). Point x-ray source of size (≤ 0.5 mm) was observed using pin hole camera. The size of the source is limited by the size of the pin hole camera. The peak current in the load is approximately 150 kA. The point x-ray source could be useful in many fields like micro lithography, medicine and to study the basic physics of high Z plasmas. (author). 4 refs., 3 figs

Chest X-Ray

Medline Plus

Full Text Available ... by Image/Video Gallery Your Radiologist Explains Chest X-ray Transcript Welcome to Radiology Info dot org! Hello, ... d like to talk with you about chest radiography also known as chest x-rays. Chest x- ...

Compact X-ray sources: X-rays from self-reflection

Science.gov (United States)

Mangles, Stuart P. D.

2012-05-01

Laser-based particle acceleration offers a way to reduce the size of hard-X-ray sources. Scientists have now developed a simple scheme that produces a bright flash of hard X-rays by using a single laser pulse both to generate and to scatter an electron beam.

Multiple-wavelength analysis of energy release during a solar flare - Thermal and nonthermal electron populations

Science.gov (United States)

Willson, Robert F.; Lang, Kenneth R.; Klein, Karl-Ludwig; Kerdraon, Alain; Trottet, Gerard

1990-01-01

Collaborative solar investigations by Tufts University and the Observatoire de Paris have resulted in simultaneous radio observations with the Very Large Array (VLA) and the Nancay Radioheliograph (NR), comparisons of this radio data with X-ray observations, and theoretical interpretations of the dominant radiation mechanisms during a weak impulsive solar flare observed on May 28, 1988. The VLA has mapped the flaring structures at time intervals of 3.3 s, showing that the preflash and flash-phase components of the impulsive emission originate in spatially separated sources. The 20.7 cm preflash source is ascribed to thermal gyroresonance emission from coronal loops with typical magnetic field strengths of up to 270 G; this emission is associated with heating and exhibits no detectable hard X-ray radiation above 30 keV. The flash-phase 20.7 cm source and the hard X-ray emission are attributed to nonthermal electrons in the coronal and chromospheric portions of a magnetic loop. The combination of imaging observations at 20.7 and 91.6 cm excludes emission from a confined hot plasma during the flash phase.

Phase-contrast X-ray imaging using an X-ray interferometer for biological imaging

Energy Technology Data Exchange (ETDEWEB)

Momose, Atsushi; Koyama, Ichiro [Tokyo Univ., Dept. of Applied Physics, Tokyo (Japan); Takeda, Tohoru; Itai, Yuji [Tsukuba Univ., Inst. of Clinical Medicine, Tsukuba, Ibaraki (Japan); Yoneyama, Akio [Hitachi Ltd., Advanced Research Laboratory, Saitama (Japan)

2002-04-01

The potential of phase-contrast X-ray imaging using an X-ray interferometer is discussed comparing with other phase-contrast X-ray imaging methods, and its principle of contrast generation is presented including the case of phase-contrast X-ray computed tomography. The status of current instrumentation is described and perspectives for practical applications are discussed. (author)

X-ray crystallography

Science.gov (United States)

2001-01-01

X-rays diffracted from a well-ordered protein crystal create sharp patterns of scattered light on film. A computer can use these patterns to generate a model of a protein molecule. To analyze the selected crystal, an X-ray crystallographer shines X-rays through the crystal. Unlike a single dental X-ray, which produces a shadow image of a tooth, these X-rays have to be taken many times from different angles to produce a pattern from the scattered light, a map of the intensity of the X-rays after they diffract through the crystal. The X-rays bounce off the electron clouds that form the outer structure of each atom. A flawed crystal will yield a blurry pattern; a well-ordered protein crystal yields a series of sharp diffraction patterns. From these patterns, researchers build an electron density map. With powerful computers and a lot of calculations, scientists can use the electron density patterns to determine the structure of the protein and make a computer-generated model of the structure. The models let researchers improve their understanding of how the protein functions. They also allow scientists to look for receptor sites and active areas that control a protein's function and role in the progress of diseases. From there, pharmaceutical researchers can design molecules that fit the active site, much like a key and lock, so that the protein is locked without affecting the rest of the body. This is called structure-based drug design.

Development of X-ray excitable luminescent probes for scanning X-ray microscopy

International Nuclear Information System (INIS)

Moronne, M.M.

1999-01-01

Transmission soft X-ray microscopy is now capable of achieving resolutions that are typically 5 times better than the best-visible light microscopes. With expected improvements in zone plate optics, an additional factor of two may be realized within the next few years. Despite the high resolution now available with X-ray microscopes and the high X-ray contrast provided by biological molecules in the soft X-ray region (λ=2-5 nm), molecular probes for localizing specific biological targets have been lacking. To circumvent this problem, X-ray excitable molecular probes are needed that can target unique biological features. In this paper we report our initial results on the development of lanthanide-based fluorescent probes for biological labeling. Using scanning luminescence X-ray microscopy (SLXM, Jacobsen et al., J. Microscopy 172 (1993) 121-129), we show that lanthanide organo-polychelate complexes are sufficiently bright and radiation resistant to be the basis of a new class of X-ray excitable molecular probes capable of providing at least a fivefold improvement in resolution over visible light microscopy. Lanthanide probes, able to bind 80-100 metal ions per molecule, were found to give strong luminescent signals with X-ray doses exceeding 10 8 Gy, and were used to label actin stress fibers and in vitro preparations of polymerized tubulin. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Projection-type X-ray microscope based on a spherical compound refractive X-ray lens

OpenAIRE

Dudchik, Yu. I.; Gary, C. K.; Park, H.; Pantell, R. H.; Piestrup, M. A.

2007-01-01

New projection- type X-ray microscope with a compound refractive lens as the optical element is presented. The microscope consists of an X-ray source that is 1-2 mm in diameter, compound X-ray lens and X-ray camera that are placed in-line to satisfy the lens formula. The lens forms an image of the X-ray source at camera sensitive plate. An object is placed between the X-ray source and the lens as close as possible to the source, and the camera shows a shadow image of the object. Spatial resol...

WE-H-204-01: William D. Coolidge, Inventor of the Modern X-Ray Tube

Energy Technology Data Exchange (ETDEWEB)

Allard, D. [PA Dept. of Environmental Protection (United States)

2016-06-15

“William D. Coolidge, Inventor of the Modern X-ray Tube” David J. Allard, M.S., CHP - Director, PA DEP Bureau of Radiation Protection William David Coolidge 1873–1975 was a research scientist and inventor of the modern X-ray tube. Besides Roentgen, with his 1895 discovery and subsequent studies of X-rays, perhaps no other individual contributed more to the advancement of X-ray technology than did Coolidge. He was born in Hudson, MA and received his Bachelor of Science degree from MIT in 1896. That same year he went to Europe to study under renowned physicists of the time. Coolidge received his Ph.D. summa cum laude from the University of Leipzig in 1899 and soon after joined the staff of MIT. While studying at Leipzig, he met Roentgen. In 1905 he was asked to join the newly established General Electric Research Laboratory in Schenectady, NY. He promptly began fundamental work on the production of ductile tungsten filaments as a replacement for fragile carbon filaments used in incandescent light bulbs. This improved light bulb was brought to market by GE in 1911. It was subsequent application of his tungsten work that led Coolidge to his studies in X ray production. Circa 1910, the state-of-the-art X-ray tube was a “gas tube” or “cold cathode” type tube. These crude X-ray tubes relied on residual gas molecules as a source of electrons for bombardment of low to medium atomic number metal targets. In 1912 Coolidge described the use of tungsten as an improved anode target material for X-ray tubes. Shortly after in 1913 he published a paper in Physical Review describing “A Powerful Roentgen Ray Tube With a Pure Electron Discharge.” This tube used a tungsten filament as a thermionic source of electrons under high vacuum to bombard a tungsten anode target. Great improvements in X-ray tube stability, output and performance were obtained with the “hot cathode” or “Coolidge tube.” With some variation in filament and target geometry, this 100 year

WE-H-204-01: William D. Coolidge, Inventor of the Modern X-Ray Tube

International Nuclear Information System (INIS)

Allard, D.

2016-01-01

“William D. Coolidge, Inventor of the Modern X-ray Tube” David J. Allard, M.S., CHP - Director, PA DEP Bureau of Radiation Protection William David Coolidge 1873–1975 was a research scientist and inventor of the modern X-ray tube. Besides Roentgen, with his 1895 discovery and subsequent studies of X-rays, perhaps no other individual contributed more to the advancement of X-ray technology than did Coolidge. He was born in Hudson, MA and received his Bachelor of Science degree from MIT in 1896. That same year he went to Europe to study under renowned physicists of the time. Coolidge received his Ph.D. summa cum laude from the University of Leipzig in 1899 and soon after joined the staff of MIT. While studying at Leipzig, he met Roentgen. In 1905 he was asked to join the newly established General Electric Research Laboratory in Schenectady, NY. He promptly began fundamental work on the production of ductile tungsten filaments as a replacement for fragile carbon filaments used in incandescent light bulbs. This improved light bulb was brought to market by GE in 1911. It was subsequent application of his tungsten work that led Coolidge to his studies in X ray production. Circa 1910, the state-of-the-art X-ray tube was a “gas tube” or “cold cathode” type tube. These crude X-ray tubes relied on residual gas molecules as a source of electrons for bombardment of low to medium atomic number metal targets. In 1912 Coolidge described the use of tungsten as an improved anode target material for X-ray tubes. Shortly after in 1913 he published a paper in Physical Review describing “A Powerful Roentgen Ray Tube With a Pure Electron Discharge.” This tube used a tungsten filament as a thermionic source of electrons under high vacuum to bombard a tungsten anode target. Great improvements in X-ray tube stability, output and performance were obtained with the “hot cathode” or “Coolidge tube.” With some variation in filament and target geometry, this 100 year

X-Ray Lasers 2016

CERN Document Server

Bulanov, Sergei; Daido, Hiroyuki; Kato, Yoshiaki

2018-01-01

These proceedings comprise a selection of invited and contributed papers presented at the 15th International Conference on X-Ray Lasers (ICXRL 2016), held at the Nara Kasugano International Forum, Japan, from May 22 to 27, 2016. This conference was part of an ongoing series dedicated to recent developments in the science and technology of x-ray lasers and other coherent x-ray sources with additional focus on supporting technologies, instrumentation and applications.   The book showcases recent advances in the generation of intense, coherent x-rays, the development of practical devices and their applications across a wide variety of fields. It also discusses emerging topics such as plasma-based x-ray lasers, 4th generation accelerator-based sources and higher harmonic generations, as well as other x-ray generation schemes.

The Mapping X-ray Fluorescence Spectrometer (MapX)

Science.gov (United States)

Sarrazin, P.; Blake, D. F.; Marchis, F.; Bristow, T.; Thompson, K.

2017-12-01

Many planetary surface processes leave traces of their actions as features in the size range 10s to 100s of microns. The Mapping X-ray Fluorescence Spectrometer (MapX) will provide elemental imaging at 100 micron spatial resolution, yielding elemental chemistry at a scale where many relict physical, chemical, or biological features can be imaged and interpreted in ancient rocks on planetary bodies and planetesimals. MapX is an arm-based instrument positioned on a rock or regolith with touch sensors. During an analysis, an X-ray source (tube or radioisotope) bombards the sample with X-rays or alpha-particles / gamma-rays, resulting in sample X-ray Fluorescence (XRF). X-rays emitted in the direction of an X-ray sensitive CCD imager pass through a 1:1 focusing lens (X-ray micro-pore Optic (MPO)) that projects a spatially resolved image of the X-rays onto the CCD. The CCD is operated in single photon counting mode so that the energies and positions of individual X-ray photons are recorded. In a single analysis, several thousand frames are both stored and processed in real-time. Higher level data products include single-element maps with a lateral spatial resolution of 100 microns and quantitative XRF spectra from ground- or instrument- selected Regions of Interest (ROI). XRF spectra from ROI are compared with known rock and mineral compositions to extrapolate the data to rock types and putative mineralogies. When applied to airless bodies and implemented with an appropriate radioisotope source for alpha-particle excitation, MapX will be able to analyze biogenic elements C, N, O, P, S, in addition to the cations of the rock-forming elements >Na, accessible with either X-ray or gamma-ray excitation. The MapX concept has been demonstrated with a series of lab-based prototypes and is currently under refinement and TRL maturation.

Warming rays in cluster cool cores

Science.gov (United States)

Colafrancesco, S.; Marchegiani, P.

2008-06-01

Context: Cosmic rays are confined in the atmospheres of galaxy clusters and, therefore, they can play a crucial role in the heating of their cool cores. Aims: We discuss here the thermal and non-thermal features of a model of cosmic ray heating of cluster cores that can provide a solution to the cooling-flow problems. To this aim, we generalize a model originally proposed by Colafrancesco, Dar & DeRujula (2004) and we show that our model predicts specific correlations between the thermal and non-thermal properties of galaxy clusters and enables various observational tests. Methods: The model reproduces the observed temperature distribution in clusters by using an energy balance condition in which the X-ray energy emitted by clusters is supplied, in a quasi-steady state, by the hadronic cosmic rays, which act as “warming rays” (WRs). The temperature profile of the intracluster (IC) gas is strictly correlated with the pressure distribution of the WRs and, consequently, with the non-thermal emission (radio, hard X-ray and gamma-ray) induced by the interaction of the WRs with the IC gas and the IC magnetic field. Results: The temperature distribution of the IC gas in both cool-core and non cool-core clusters is successfully predicted from the measured IC plasma density distribution. Under this contraint, the WR model is also able to reproduce the thermal and non-thermal pressure distribution in clusters, as well as their radial entropy distribution, as shown by the analysis of three clusters studied in detail: Perseus, A2199 and Hydra. The WR model provides other observable features of galaxy clusters: a correlation of the pressure ratio (WRs to thermal IC gas) with the inner cluster temperature (P_WR/P_th) ˜ (kT_inner)-2/3, a correlation of the gamma-ray luminosity with the inner cluster temperature Lγ ˜ (kT_inner)4/3, a substantial number of cool-core clusters observable with the GLAST-LAT experiment, a surface brightness of radio halos in cool-core clusters

Combined optic system based on polycapillary X-ray optics and single-bounce monocapillary optics for focusing X-rays from a conventional laboratory X-ray source

Energy Technology Data Exchange (ETDEWEB)

Sun, Xuepeng; Liu, Zhiguo [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Sun, Tianxi, E-mail: stx@bnu.edu.cn [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Yi, Longtao; Sun, Weiyuan; Li, Fangzuo; Jiang, Bowen [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ma, Yongzhong [Center for Disease Control and Prevention of Beijing, Beijing 100013 (China); Ding, Xunliang [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

2015-12-01

Two combined optic systems based on polycapillary X-ray optics and single-bounce monocapillary optics (SBMO) were designed for focusing the X-rays from a conventional laboratory X-ray source. One was based on a polycapillary focusing X-ray lens (PFXRL) and a single-bounce ellipsoidal capillary (SBEC), in which the output focal spot with the size of tens of micrometers of the PFXRL was used as the “virtual” X-ray source for the SBEC. The other system was based on a polycapillary parallel X-ray lens (PPXRL) and a single-bounce parabolic capillary (SBPC), in which the PPXRL transformed the divergent X-ray beam from an X-ray source into a quasi-parallel X-ray beam with the divergence of sever milliradians as the incident illumination of the SBPC. The experiment results showed that the combined optic systems based on PFXRL and SBEC with a Mo rotating anode X-ray generator with the focal spot with a diameter of 300 μm could obtain a focal spot with the total gain of 14,300 and focal spot size of 37.4 μm, and the combined optic systems based on PPXRL and SBPC with the same X-ray source mentioned above could acquire a focal spot with the total gain of 580 and focal spot size of 58.3 μm, respectively. The two combined optic systems have potential applications in micro X-ray diffraction, micro X-ray fluorescence, micro X-ray absorption near edge structure, full field X-ray microscopes and so on.

Wavelength dispersive X-ray absorption fine structure imaging by parametric X-ray radiation

International Nuclear Information System (INIS)

Inagaki, Manabu; Sakai, Takeshi; Sato, Isamu; Hayakawa, Yasushi; Nogami, Kyoko; Tanaka, Toshinari; Hayakawa, Ken; Nakao, Keisuke

2008-01-01

The parametric X-ray radiation (PXR) generator system at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University is a monochromatic and coherent X-ray source with horizontal wavelength dispersion. The energy definition of the X-rays, which depends on the horizontal size of the incident electron beam on the generator target crystal, has been investigated experimentally by measuring the X-ray absorption near edge structure (XANES) spectra on Cu and CuO associated with conventional X-ray absorption imaging technique. The result demonstrated the controllability of the spectrum resolution of XANES by adjusting of the horizontal electron beam size on the target crystal. The XANES spectra were obtained with energy resolution of several eV at the narrowest case, which is in qualitative agreement with the energy definition of the PXR X-rays evaluated from geometrical consideration. The result also suggested that the wavelength dispersive X-ray absorption fine structure measurement associated with imaging technique is one of the promising applications of PXR. (author)

X-RAYS FROM A RADIO-LOUD COMPACT BROAD ABSORPTION LINE QUASAR 1045+352 AND THE NATURE OF OUTFLOWS IN RADIO-LOUD BROAD ABSORPTION LINE QUASARS

International Nuclear Information System (INIS)

Kunert-Bajraszewska, Magdalena; Katarzynski, Krzysztof; Siemiginowska, Aneta; Janiuk, Agnieszka

2009-01-01

We present new results on X-ray properties of radio-loud broad absorption line (BAL) quasars and focus on broadband spectral properties of a high-ionization BAL (HiBAL) compact steep spectrum (CSS) radio-loud quasar 1045+352. This HiBAL quasar has a very complex radio morphology indicating either strong interactions between a radio jet and the surrounding interstellar medium or a possible re-start of the jet activity. We detected 1045+352 quasar in a short 5 ksec Chandra ACIS-S observation. We applied theoretical models to explain spectral energy distribution of 1045+352 and argue that non-thermal, inverse-Compton (IC) emission from the innermost parts of the radio jet can account for a large fraction of the observed X-ray emission. In our analysis, we also consider a scenario in which the observed X-ray emission from radio-loud BAL quasars can be a sum of IC jet X-ray emission and optically thin corona X-ray emission. We compiled a sample of radio-loud BAL quasars that were observed in X-rays to date and report no correlation between their X-ray and radio luminosity. However, the radio-loud BAL quasars show a large range of X-ray luminosities and absorption columns. This is consistent with the results obtained earlier for radio-quiet BAL quasars and may indicate an orientation effect in BAL quasars or more complex dependence between X-ray emission, radio emission, and an orientation based on the radio morphology.

THE PLERIONIC SUPERNOVA REMNANT G21.5-0.9 POWERED BY PSR J1833-1034: NEW SPECTROSCOPIC AND IMAGING RESULTS REVEALED WITH THE CHANDRA X-RAY OBSERVATORY

International Nuclear Information System (INIS)

Matheson, Heather; Safi-Harb, Samar

2010-01-01

In 1999, the Chandra X-ray Observatory revealed a 150'' radius halo surrounding the 40'' radius pulsar wind nebula (PWN) G21.5-0.9. A 2005 imaging study of G21.5-0.9 showed that the halo is limb-brightened and suggested that this feature is a candidate for the long-sought supernova remnant (SNR) shell. We present a spectral analysis of SNR G21.5-0.9, using the longest effective observation to date (578.6 ks with the Advanced CCD Imaging Spectrometer (ACIS) and 278.4 ks with the High-Resolution Camera (HRC)) to study unresolved questions about the spectral nature of remnant features, such as the limb brightening of the X-ray halo and the bright knot in the northern part of the halo. The Chandra analysis favors the non-thermal interpretation of the limb. Its spectrum is fit well with a power-law model with a photon index Γ = 2.13 (1.94-2.33) and a luminosity of L x (0.5-8 keV) = (2.3 ± 0.6) x 10 33 erg s -1 (at an assumed distance of 5.0 kpc). An srcut model was also used to fit the spectrum between the radio and X-ray energies. While the absence of a shell in the radio still prohibits constraining the spectrum at radio wavelengths, we assume a range of spectral indices to infer the 1 GHz flux density and the rolloff frequency of the synchrotron spectrum in X-rays and find that the maximum energy to which electrons are accelerated at the shock ranges from ∼60 to 130 TeV (B/10 μG) -1/2 , where B is the magnetic field in units of μG. For the northern knot, we constrain previous models and find that a two-component power-law (or srcut) + pshock model provides an adequate fit, with the pshock model requiring a very low ionization timescale and solar abundances for Mg and Si. Our spectroscopic study of PSR J1833-1034, the highly energetic pulsar powering G21.5-0.9, shows that its spectrum is dominated by hard non-thermal X-ray emission with some evidence of a thermal component that represents ∼9% of the observed non-thermal emission and that suggests non

The one million volt X-ray therapy equipment at St Bartholomew's Hospital, 1936-1960

International Nuclear Information System (INIS)

Innes, G.S.

1988-01-01

St Bartholomew's Hospital in 1934 placed a contract with Messrs Metropolitan Vickers, of Manchester, for an X-ray therapy equipment to operate at 600 kV, 2mA d.c., but with the proviso that every effort would be made to attain an operating condition of 1000 kV, 4mA. The X-ray tube and rectifiers were to be continuously evacuated and demountable. This meant that components such as filaments, anodes and the target could be easily replaced, so providing cheap maintenance and continuous availability of the plant. No specification exists today, but one was assembled from the minutes of the Cancer Committee of the hospital and the contract pricing. A brief outline historical review is also presented, particularly of the personalities involved, and the War years 1939-1945. (author)

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... are the limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray ( ... leg (shin), ankle or foot. top of page What are some common uses of the procedure? A ...

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... current x-ray images for diagnosis and disease management. top of page How is the procedure performed? ... standards used by radiology professionals. Modern x-ray systems have very controlled x-ray beams and dose ...

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... that might interfere with the x-ray images. Women should always inform their physician and x-ray ... Safety page for more information about radiation dose. Women should always inform their physician or x-ray ...

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... of knee x-rays. A portable x-ray machine is a compact apparatus that can be taken ... of the body being examined, an x-ray machine produces a small burst of radiation that passes ...

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... drawer under the table holds the x-ray film or image recording plate . Sometimes the x-ray ... extended over the patient while an x-ray film holder or image recording plate is placed beneath ...

Thick filament mechano-sensing is a calcium-independent regulatory mechanism in skeletal muscle.

Science.gov (United States)

Fusi, L; Brunello, E; Yan, Z; Irving, M

2016-10-31

Recent X-ray diffraction studies on actively contracting fibres from skeletal muscle showed that the number of myosin motors available to interact with actin-containing thin filaments is controlled by the stress in the myosin-containing thick filaments. Those results suggested that thick filament mechano-sensing might constitute a novel regulatory mechanism in striated muscles that acts independently of the well-known thin filament-mediated calcium signalling pathway. Here we test that hypothesis using probes attached to the myosin regulatory light chain in demembranated muscle fibres. We show that both the extent and kinetics of thick filament activation depend on thick filament stress but are independent of intracellular calcium concentration in the physiological range. These results establish direct control of myosin motors by thick filament mechano-sensing as a general regulatory mechanism in skeletal muscle that is independent of the canonical calcium signalling pathway.

X-ray holography

International Nuclear Information System (INIS)

Faigel, G.; Tegze, M.; Belakhovsky, M.; Marchesini, S.; Bortel, G.

2003-01-01

In the last decade holographic methods using hard X-rays were developed. They are able to resolve atomic distances, and can give the 3D arrangement of atoms around a selected element. Therefore, hard X-ray holography has potential applications in chemistry, biology and physics. In this article we give a general description of these methods and discuss the developments in the experimental technique. The capabilities of hard X-ray holography are demonstrated by examples

X-ray Emitting GHz-Peaked Spectrum Galaxies: Testing a Dynamical-Radiative Model with Broad-Band Spectra

International Nuclear Information System (INIS)

Ostorero, L.; Moderski, R.; Stawarz, L.; Diaferio, A.; Kowalska, I.; Cheung, C.C.; Kataoka, J.; Begelman, M.C.; Wagner, S.J.

2010-01-01

In a dynamical-radiative model we recently developed to describe the physics of compact, GHz-Peaked-Spectrum (GPS) sources, the relativistic jets propagate across the inner, kpc-sized region of the host galaxy, while the electron population of the expanding lobes evolves and emits synchrotron and inverse-Compton (IC) radiation. Interstellar-medium gas clouds engulfed by the expanding lobes, and photoionized by the active nucleus, are responsible for the radio spectral turnover through free-free absorption (FFA) of the synchrotron photons. The model provides a description of the evolution of the GPS spectral energy distribution (SED) with the source expansion, predicting significant and complex high-energy emission, from the X-ray to the γ-ray frequency domain. Here, we test this model with the broad-band SEDs of a sample of eleven X-ray emitting GPS galaxies with Compact-Symmetric-Object (CSO) morphology, and show that: (i) the shape of the radio continuum at frequencies lower than the spectral turnover is indeed well accounted for by the FFA mechanism; (ii) the observed X-ray spectra can be interpreted as non-thermal radiation produced via IC scattering of the local radiation fields off the lobe particles, providing a viable alternative to the thermal, accretion-disk dominated scenario. We also show that the relation between the hydrogen column densities derived from the X-ray (N H ) and radio (N HI ) data of the sources is suggestive of a positive correlation, which, if confirmed by future observations, would provide further support to our scenario of high-energy emitting lobes.

Ultrashort X-ray pulse science

Energy Technology Data Exchange (ETDEWEB)

Chin, Alan Hap [Univ. of California, Berkeley, CA (US). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

1998-05-01

A variety of phenomena involves atomic motion on the femtosecond time-scale. These phenomena have been studied using ultrashort optical pulses, which indirectly probe atomic positions through changes in optical properties. Because x-rays can more directly probe atomic positions, ultrashort x-ray pulses are better suited for the study of ultrafast structural dynamics. One approach towards generating ultrashort x-ray pulses is by 90° Thomson scattering between terawatt laser pulses and relativistic electrons. Using this technique, the author generated ~ 300 fs, 30 keV (0.4 Å) x-ray pulses. These x-ray pulses are absolutely synchronized with ultrashort laser pulses, allowing femtosecond optical pump/x-ray probe experiments to be performed. Using the right-angle Thomson scattering x-ray source, the author performed time-resolved x-ray diffraction studies of laser-perturbated InSb. These experiments revealed a delayed onset of lattice expansion. This delay is due to the energy relaxation from a dense electron-hole plasma to the lattice. The dense electron-hole plasma first undergoes Auger recombination, which reduces the carrier concentration while maintaining energy content. Longitudinal-optic (LO) phonon emission then couples energy to the lattice. LO phonon decay into acoustic phonons, and acoustic phonon propagation then causes the growth of a thermally expanded layer. Source characterization is instrumental in utilizing ultrashort x-ray pulses in time-resolved x-ray spectroscopies. By measurement of the electron beam diameter at the generation point, the pulse duration of the Thomson scattered x-rays is determined. Analysis of the Thomson scattered x-ray beam properties also provides a novel means of electron bunch characterization. Although the pulse duration is inferred for the Thomson scattering x-ray source, direct measurement is required for other x-ray pulse sources. A method based on the laser-assisted photoelectric effect (LAPE) has been demonstrated as a

Ultrashort X-ray pulse science

International Nuclear Information System (INIS)

Chin, A.H.; Lawrence Berkeley National Lab., CA

1998-01-01

A variety of phenomena involves atomic motion on the femtosecond time-scale. These phenomena have been studied using ultrashort optical pulses, which indirectly probe atomic positions through changes in optical properties. Because x-rays can more directly probe atomic positions, ultrashort x-ray pulses are better suited for the study of ultrafast structural dynamics. One approach towards generating ultrashort x-ray pulses is by 90 o Thomson scattering between terawatt laser pulses and relativistic electrons. Using this technique, the author generated ∼ 300 fs, 30 keV (0.4 (angstrom)) x-ray pulses. These x-ray pulses are absolutely synchronized with ultrashort laser pulses, allowing femtosecond optical pump/x-ray probe experiments to be performed. Using the right-angle Thomson scattering x-ray source, the author performed time-resolved x-ray diffraction studies of laser-perturbated InSb. These experiments revealed a delayed onset of lattice expansion. This delay is due to the energy relaxation from a dense electron-hole plasma to the lattice. The dense electron-hole plasma first undergoes Auger recombination, which reduces the carrier concentration while maintaining energy content. Longitudinal-optic (LO) phonon emission then couples energy to the lattice. LO phonon decay into acoustic phonons, and acoustic phonon propagation then causes the growth of a thermally expanded layer. Source characterization is instrumental in utilizing ultrashort x-ray pulses in time-resolved x-ray spectroscopies. By measurement of the electron beam diameter at the generation point, the pulse duration of the Thomson scattered x-rays is determined. Analysis of the Thomson scattered x-ray beam properties also provides a novel means of electron bunch characterization. Although the pulse duration is inferred for the Thomson scattering x-ray source, direct measurement is required for other x-ray pulse sources. A method based on the laser-assisted photoelectric effect (LAPE) has been

A reaction cell with sample laser heating for in situ soft X-ray absorption spectroscopy studies under environmental conditions.

Science.gov (United States)

Escudero, Carlos; Jiang, Peng; Pach, Elzbieta; Borondics, Ferenc; West, Mark W; Tuxen, Anders; Chintapalli, Mahati; Carenco, Sophie; Guo, Jinghua; Salmeron, Miquel

2013-05-01

A miniature (1 ml volume) reaction cell with transparent X-ray windows and laser heating of the sample has been designed to conduct X-ray absorption spectroscopy studies of materials in the presence of gases at atmospheric pressures. Heating by laser solves the problems associated with the presence of reactive gases interacting with hot filaments used in resistive heating methods. It also facilitates collection of a small total electron yield signal by eliminating interference with heating current leakage and ground loops. The excellent operation of the cell is demonstrated with examples of CO and H2 Fischer-Tropsch reactions on Co nanoparticles.

Wide-area phase-contrast X-ray imaging using large X-ray interferometers

Energy Technology Data Exchange (ETDEWEB)

Momose, Atsushi E-mail: momose@exp.t.u-tokyo.ac.jp; Takeda, Tohoru; Yoneyama, Akio; Koyama, Ichiro; Itai, Yuji

2001-07-21

Large X-ray interferometers are developed for phase-contrast X-ray imaging aiming at medical applications. A monolithic X-ray interferometer and a separate one are studied, and currently a 25 mmx20 mm view area can be generated. This paper describes the strategy of our research program and some recent developments.

Wide-area phase-contrast X-ray imaging using large X-ray interferometers

Science.gov (United States)

Momose, Atsushi; Takeda, Tohoru; Yoneyama, Akio; Koyama, Ichiro; Itai, Yuji

2001-07-01

Large X-ray interferometers are developed for phase-contrast X-ray imaging aiming at medical applications. A monolithic X-ray interferometer and a separate one are studied, and currently a 25 mm×20 mm view area can be generated. This paper describes the strategy of our research program and some recent developments.

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... x-rays. top of page What does the equipment look like? The equipment typically used for bone x-rays consists of ... and joint abnormalities, such as arthritis. X-ray equipment is relatively inexpensive and widely available in emergency ...

Material Discriminated X-Ray CT System by Using New X-Ray Imager with Energy Discriminate Function

Directory of Open Access Journals (Sweden)

Toru Aoki

2008-04-01

Full Text Available Material discriminated X-ray CT system has been constructed by using conventional X-ray tube (white X-ray source and photon-counting X-ray imager as an application with energy band detection. We have already reported material identify X-ray CT using K-shell edge method elsewhere. In this report the principle of material discrimination was adapted the separation of electron-density and atomic number from attenuation coefficient mapping in X-ray CT reconstructed image in two wavelength X-ray CT method using white X-ray source and energy discriminated X-ray imager by using two monochrome X-ray source method. The measurement phantom was prepared as four kinds material rods (Carbon(C, Iron(Fe, Copper(Cu, Titanium(Ti rods of 3mm-diameter inside an aluminum(Al rod of 20mm-diameter. We could observed material discriminated X-ray CT reconstructed image, however, the discrimination properties were not good than two monochrome X-ray CT method. This results was could be explained because X-ray scattering, beam-hardening and so on based on white X-ray source, which could not observe in two monochrome X-ray CT method. However, since our developed CdTe imager can be detect five energy-bands at the same time, we can use multi-band analysis to decrease the least square error margin. We will be able to obtain more high separation in atomic number mapping in X-ray CT reconstructed image by using this system.

A Liquid-Cryogen-Free Superconducting Tunnel Junction X-ray Spectrometer for Astrobiology Research at the Synchrotron

Energy Technology Data Exchange (ETDEWEB)

Friedrich, S; Drury, O B; Hertrich, T; Hoehne, J

2008-06-15

Superconducting tunnel junctions (STJs) are being developed as energy-dispersive soft X-ray detectors, because they combine the high energy resolution of low-temperature detectors with the comparably high count rates of non-thermal devices. We have built a 36-pixel spectrometer based on 200 {micro}m x 200 {micro}m Nb-Al-AlOx-Al-Nb STJs. It offers an energy resolution of {approx}10 to 20 eV FWHM in the soft X-ray band below 1 keV, a solid angle coverage {Omega}/4{pi} {approx} 10{sup -3}, and can be operated at total rates up to {approx}10{sup 6} counts/s. For STJ operation by non-expert users, we have built a liquid-cryogen-free spectrometer with a mechanical pulse-tube cryocooler and a two-stage adiabatic demagnetization refrigerator. It is fully automated for cooldown to a base temperature of <30 mK in 15 hours, and has a hold time of >3 days between demagnetization cycles for STJ operation at 0.3 K. The STJ spectrometers are used for speciation measurements on dilute samples by fluorescence-detected X-ray absorption spectroscopy, and can achieve sensitivities below 100 ppm. We discuss the spectrometer performance in representative applications on metals in meteorites in the context of geological signatures of biological activity.

X-Pinch And Its Applications In X-ray Radiograph

International Nuclear Information System (INIS)

Zou Xiaobing; Wang Xinxin; Liu Rui; Zhao Tong; Zeng Naigong; Zhao Yongchao; Du Yanqiang

2009-01-01

An X-pinch device and the related diagnostics of x-ray emission from X-pinch were briefly described. The time-resolved x-ray measurements with photoconducting diodes show that the x-ray pulse usually consists of two subnanosecond peaks with a time interval of about 0.5 ns. Being consistent with these two peaks of the x-ray pulse, two point x-ray sources of size ranging from 100 μm to 5 μm and depending on cut-off x-ray photon energy were usually observed on the pinhole pictures. The x-pinch was used as x-ray source for backlighting of the electrical explosion of single wire and the evolution of X-pinch, and for phase-contrast imaging of soft biological objects such as a small shrimp and a mosquito.

Chest X-Ray (Chest Radiography)

Science.gov (United States)

... Resources Professions Site Index A-Z X-ray (Radiography) - Chest Chest x-ray uses a very small dose ... Radiography? What is a Chest X-ray (Chest Radiography)? The chest x-ray is the most commonly performed diagnostic ...

Radio and X-ray observations of a multiple impulsive solar burst with high time resolution

International Nuclear Information System (INIS)

Kosugi, T.

1981-01-01

A well-developed multiple impulsive microwave burst occurred on February 17, 1979 simultaneously with a hard X-ray burst and a large group of type III bursts at metric wavelengths. The whole event is composed of serveral subgroups of elementary spike bursts. Detailed comparisons between these three classes of emissions with high time resolution of approx. equal to0.5 s reveal that individual type III bursts coincide in time with corresponding elementary X-ray and microwave spike bursts. It suggests that a non-thermal electron pulse generating a type III spike burst is produced simultaneously with those responsible for the corresponding hard X-ray and microwave spike bursts. The rise and decay characteristic time scales of the elementary spike burst are << 1 s, and approx. equal to1 s and approx. equal to3 s for type III, hard X-ray and microwave emissions respectively. Radio interferometric observations made at 17 GHz reveal that the spatial structure varies from one subgroup to others while it remains unchanged in a subgroup. Spectral evolution of the microwave burst seems to be closely related to the spatial evolution. The spatial evolution together with the spectral evolution suggests that the electron-accelerating region shifts to a different location after it stays at one location for several tens of seconds, duration of a subgroup of elementary spike bursts. We discuss several requirements for a model of the impulsive burst which come out from these observational results, and propose a migrating double-source model. (orig.)

X-ray luminescent glasses

International Nuclear Information System (INIS)

Takahashi, T.; Yamada, O.

1981-01-01

X-ray luminescent glasses comprising a divalent cation such as an alkaline earth metal or other divalent cations such as pb, cd, or zn, and certain rare earth metaphosphates are suitable as vitreous, x-ray phosphors or x-ray luminescent glass fibers in an x-ray intensifying screen. The glasses have the composition n(Mo X p2o5)((1-y)tb2o3 X yce2o3 X 3p2o5) wherein N is greater than zero but less than or equal to 16, M is an alkaline earth metal or other divalent cation such as pb, cd, or zn, and Y is greater than or equal to zero but less than one

Modeling Flare Hard X-ray Emission from Electrons in Contracting Magnetic Islands

Science.gov (United States)

Guidoni, Silvina E.; Allred, Joel C.; Alaoui, Meriem; Holman, Gordon D.; DeVore, C. Richard; Karpen, Judith T.

2016-05-01

The mechanism that accelerates particles to the energies required to produce the observed impulsive hard X-ray emission in solar flares is not well understood. It is generally accepted that this emission is produced by a non-thermal beam of electrons that collides with the ambient ions as the beam propagates from the top of a flare loop to its footpoints. Most current models that investigate this transport assume an injected beam with an initial energy spectrum inferred from observed hard X-ray spectra, usually a power law with a low-energy cutoff. In our previous work (Guidoni et al. 2016), we proposed an analytical method to estimate particle energy gain in contracting, large-scale, 2.5-dimensional magnetic islands, based on a kinetic model by Drake et al. (2010). We applied this method to sunward-moving islands formed high in the corona during fast reconnection in a simulated eruptive flare. The overarching purpose of the present work is to test this proposed acceleration model by estimating the hard X-ray flux resulting from its predicted accelerated-particle distribution functions. To do so, we have coupled our model to a unified computational framework that simulates the propagation of an injected beam as it deposits energy and momentum along its way (Allred et al. 2015). This framework includes the effects of radiative transfer and return currents, necessary to estimate flare emission that can be compared directly to observations. We will present preliminary results of the coupling between these models.

X-ray electromagnetic application technology

International Nuclear Information System (INIS)

2011-01-01

The investigating committee aimed at research on electromagnetic fields in functional devices and X-ray fibers for efficient coherent X-ray generation and their material science, high-precision manufacturing, particularly for X-ray electromagnetic application technology from January 2006 to December 2008. In this report, we describe our research results, in particular, on the topics of synchrotron radiation and free-electron laser, Saga Synchrotron Project, X-ray waveguides and waveguide-based lens-less hard-X-ray imaging, X-ray nanofocusing for capillaries and zone plates, dispersion characteristics in photonics crystal consisting of periodic atoms for nanometer waveguides, electromagnetic characteristics of grid structures for scattering fields of nano-meter electromagnetic waves and X-rays, FDTD parallel computing of fundamental scattering and attenuation characteristics of X-ray for medical imaging diagnosis, orthogonal relations of electromagnetic fields including evanescent field in dispersive medium. (author)

Legal directives in the X-ray regulation for the field of X-ray diagnostics

International Nuclear Information System (INIS)

Huhn, Walter

2012-01-01

The operation of each X-ray device is subject to the requirements of the X-ray regulations (RoeV); for different operational modes or applications like curative diagnostics, X-ray serial examinations, X-ray radiotherapy and teleradiology different directives exist and have to be respected. The report discusses the issues licensing and notification procedures, radiation protection representative, requirements for the commissioning (teleradiology, serial X.ray examinations), technical qualification and radiation protection knowledge of physicians, technical qualification of the assistant personnel.

High-speed X-ray topography

International Nuclear Information System (INIS)

Eckers, W.; Oppolzer, H.

1977-01-01

The investigation of lattice defects in semiconductor crystals by conventional X-ray diffraction topography is very time-consuming. Exposure times can be reduced by using high-intensity X-rays and X-ray image intensifiers. The described system comprises a high-power rotating-anode X-ray tube, a remote-controlled X-ray topography camera, and a television system operating with an X-ray sensing VIDICON. System performance is demonstrated with reference to exploratory examples. The exposure time for photographic plates is reduced to 1/20 and for the X-ray TV system (resolution of the order of 30 μm) to 1/100 relative to that required when using a conventional topography system. (orig.) [de

13.1 micrometers hard X-ray focusing by a new type monocapillary X-ray optic designed for common laboratory X-ray source

Science.gov (United States)

Sun, Xuepeng; zhang, Xiaoyun; Zhu, Yu; Wang, Yabing; Shang, Hongzhong; Zhang, Fengshou; Liu, Zhiguo; Sun, Tianxi

2018-04-01

A new type of monocapillary X-ray optic, called 'two bounces monocapillary X-ray optics' (TBMXO), is proposed for generating a small focal spot with high power-density gain for micro X-ray analysis, using a common laboratory X-ray source. TBMXO is consists of two parts: an ellipsoidal part and a tapered part. Before experimental testing, the TBMXO was simulated by the ray tracing method in MATLAB. The simulated results predicted that the proposed TBMXO would produce a smaller focal spot with higher power-density gain than the ellipsoidal monocapillary X-ray optic (EMXO). In the experiment, the TBMXO performance was tested by both an optical device and a Cu target X-ray tube with focal spot of 100 μm. The results indicated that the TBMXO had a slope error of 57.6 μrad and a 13.1 μm focal spot and a 1360 gain in power density were obtained.

Effects of X-ray tube parameters on thickness measure precision in X-ray profile gauge

International Nuclear Information System (INIS)

Miao Jichen; Wu Zhifang; Xing Guilai

2011-01-01

Instantaneous profile gauge technology has been widely used in metallurgy industry because it can on-line get the profile of steel strip. It has characters of high measure precision and wide measure range, but the X-ray tube parameters only can be set few different values during measurement. The relations of thickness measure precision and X-ray tube current, X-ray tube voltage were analyzed. The results show that the X-ray tube current affects the thickness measure precision and the X-ray tube voltage determines the thickness measure range. The method of estimating the X-ray current by thickness measure precision was provided in the end. This method is the base of X-ray source selection and X-ray source parameter's setting in the instantaneous profile gauge. (authors)

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... X-rays are a form of radiation like light or radio waves. X-rays pass through most objects, including the body. Once it is carefully aimed at the part of the body being examined, an x-ray machine produces a small ...

X-Ray Exam: Hip

Science.gov (United States)

... for Educators Search English Español X-Ray Exam: Hip KidsHealth / For Parents / X-Ray Exam: Hip What's in this article? What It Is Why ... You Have Questions Print What It Is A hip X-ray is a safe and painless test ...

X-Ray Exam: Ankle

Science.gov (United States)

... for Educators Search English Español X-Ray Exam: Ankle KidsHealth / For Parents / X-Ray Exam: Ankle What's in this article? What It Is Why ... You Have Questions Print What It Is An ankle X-ray is a safe and painless test ...

Shield device for controlling the dose of x-rays applied in an x-ray machine

International Nuclear Information System (INIS)

Charrier, P.

1983-01-01

This invention provides an improved shield for use with an x-ray machine. The shield can control the dose of x-rays applied by the machine in different areas without affecting the power of the x-rays. This is achieved with a shield especially designed and positioned to intercept with x-rays for longer or shorter periods in different areas during the taking of the picture, but not for the whole period of time necessary for taking this picture. Each area of the subject being x-rayed is exposed to full power x-rays. However, owing to the shield, the areas that require smaller dose receive these full power x-rays for a shorter portion of the time required to take the picture while the other areas that require larger dose of x-rays, receive the full power x-rays for a longer portion of the full period of time required to take the picture. To ensure this differential exposure, the shield is placed through the path of the x-rays and rotated about an axis which is generally transverse to the direction of travel of the x-rays to cut out some of said x-rays for different portions of the period of time necessary for taking the picture. The shield is preferably shaped to intercept x-rays for a longer period in some areas than in others depending on the required doses. A plurality of differently shaped shields can be provided to suit different picture taking situations

X-Ray Exam: Cervical Spine

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español X-Ray Exam: Cervical Spine KidsHealth / For Parents / X-Ray ... MRI): Lumbar Spine Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

Differences of X-ray exposure between X-ray diagnostics with a conventional X-ray screen-system and with an image-intensifier-television-unit

International Nuclear Information System (INIS)

Loehr, H.; Vogel, H.; Reinhart, J.; Jantzen, R.

1977-01-01

During X-ray diagnostics of patients in the II. Medizinische Poliklinik the X-ray exposure was determined. It corresponded to the data described in literature. Two groups were compared: 518 patients examined with a conventional X-ray screen-system and 642 patients examined with an image-intensifier-television-system. The results demonstrated that with exception of thoracical X-ray examination the replacing of the old system by the television system brought a remarkable increase of the X-ray exposure. The doses depended of the patients constitution to a high degree. (orig.) [de

Applications of phase-contrast x-ray imaging to medicine using an x-ray interferometer

Science.gov (United States)

Momose, Atsushi; Yoneyama, Akio; Takeda, Tohoru; Itai, Yuji; Tu, Jinhong; Hirano, Keiichi

1999-10-01

We are investigating possible medical applications of phase- contrast X-ray imaging using an X-ray interferometer. This paper introduces the strategy of the research project and the present status. The main subject is to broaden the observation area to enable in vivo observation. For this purpose, large X-ray interferometers were developed, and 2.5 cm X 1.5 cm interference patterns were generated using synchrotron X-rays. An improvement of the spatial resolution is also included in the project, and an X-ray interferometer designed for high-resolution phase-contrast X-ray imaging was fabricated and tested. In parallel with the instrumental developments, various soft tissues are observed by phase- contrast X-ray CT to find correspondence between the generated contrast and our histological knowledge. The observation done so far suggests that cancerous tissues are differentiated from normal tissues and that blood can produce phase contrast. Furthermore, this project includes exploring materials that modulate phase contrast for selective imaging.

X-ray spectral meter of high voltages for X-ray apparatuses

International Nuclear Information System (INIS)

Zubkov, I.P.; Larchikov, Yu.V.

1993-01-01

Design of the X-ray spectral meter of high voltages (XRSMHV) for medical X-ray apparatuses permitting to conduct the voltage measurements without connection to current circuits. The XRSMHV consists of two main units: the detector unit based on semiconductor detector and the LP4900B multichannel analyzer (Afora, Finland). The XRSMYV was tested using the pilot plant based on RUM-20 X-ray diagnostic apparatus with high-voltage regulator. It was shown that the developed XRSMHV could be certify in the range of high constant voltages form 40 up to 120 kV with the basic relative error limits ±0.15%. The XRSMHV is used at present as the reference means for calibration of high-voltage medical X-ray equipment

Feasibility of using continuous X-ray to simulate cable response under X-ray environment

International Nuclear Information System (INIS)

Ma Liang; Zhou Hui; Cheng Yinhui; Wu Wei; Li Jinxi; Zhao Mo; Guo Jinghai

2014-01-01

The mechanism and simulating method of cable response induced by X-ray were researched, and the relationship of cable response irradiated by continuous and pulsed X-ray was analyzed. A one-dimension model of strip line irradiation response of X-ray was given, which includes the gap between cable shield and dielectric, and induced conductivity in cable dielectric. The calculation result using the model indicates that the cable responses of continuous and rectangular-pulsed X-ray have the similar current waveform and the same gap voltages. Therefore, continuous X-ray can be used to research some cable responses of pulsed X-ray irradiation under the mechanism described in the one-dimension model. (authors)

X-ray cardiovascular examination apparatus

International Nuclear Information System (INIS)

1977-01-01

An X-ray source is mounted in an enclosure for angulating longitudinally about a horizontal axis. An X-ray-permeable, patient-supporting table is mounted on the top of the enclosure for executing lateral and longitudinal movements. An X-ray image-receiving device such as an X-ray image intensifier is mounted above the table on a vertically movable arm which is on a longitudinally movable carriage. Electric control means are provided for angulating the X-ray source and image intensifier synchronously as the image intensifier system is shifted longitudinally or vertically such that the central ray from the X-ray source is kept intensifier

Application of soft X-ray microscopy to environmental microbiology of hydrosphere

International Nuclear Information System (INIS)

Takemoto, K; Yoshimura, M; Namba, H; Kihara, H; Ohigashi, T; Inagaki, Y

2017-01-01

Microstructures of unprocessed filamentous cyanobacterium, Pseudanabaena foetida sp., producing a musty smell were observed using soft X-ray microscopy. Carbon-enriched structures and granules as well as oxygen-enriched granules which have been already reported were observed. Except for early log growth phase, the oxygen-enriched granules were observed. However, the carbon-enriched structures were observed throughout log growth phase. The result suggests there is a relationship between the oxygen-enriched granules and 2-methylisoborneol (2-MIB) productivity, since the 2-MIB productivity of each cell is increased depending on the culture period in log growth phase. (paper)

Effect of Electric Voltage and Current of X-ray Chamber on the Element inthe Zirconium Alloy Analysis X-ray by X-ray Fluorescence

International Nuclear Information System (INIS)

Yusuf-Nampira; Narko-Wibowo, L; Rosika-Krisnawati; Nudia-Barenzani

2000-01-01

The using of x-ray fluorescence in the chemical analysis depend heavilyon the parameters of x-ray chamber, for examples : electric voltage andelectric current. That parameter give effect in the result of determine ofSn, Cr, Fe and Ni in the zirconium alloy. 20 kV electric voltages are used onthe Mo x-ray chamber shall product x-ray of zirconium in the sample materialcan give effect in the stability of the analysis result (deviation more than5%). The result of analysis of elements in the zirconium alloy shall givedeviation less than 5% when using of electric voltage of the x-ray chamberless than 19 kV. The sensitivity of analysis can be reached by step upelectric current of x-ray chamber. (author)

Surface modification of biphasic calcium phosphate scaffolds by non-thermal atmospheric pressure nitrogen and air plasma treatment for improving osteoblast attachment and proliferation

International Nuclear Information System (INIS)

Choi, Yu-Ri; Kwon, Jae-Sung; Song, Doo-Hoon; Choi, Eun Ha; Lee, Yong-Keun; Kim, Kyoung-Nam; Kim, Kwang-Mahn

2013-01-01

Surface modifications induced by non-thermal plasma have been used extensively in biomedical applications. The attachment and proliferation of osteoblast cells are important in bone tissue engineering using scaffolds. Hence the effect of non-thermal plasma on hydroxyapatite/β-tri-calcium phosphate (HA/β-TCP) scaffolds in terms of improving osteoblast attachment and proliferation was investigated. Experimental groups were treated with non-thermal plasma for 10 min and 20 min and a control group was not treated with non-thermal plasma. For surface chemistry analysis, X-ray photoelectron spectroscopy (XPS) analysis was carried out. The hydrophilicity was determined from contact angle measurement on the surface. Atomic force microscopy analysis (AFM) was used to test the change in surface roughness and cell attachment and proliferation were evaluated using MC3T3-E1 osteoblast cells. XPS spectra revealed a decreased amount of carbon on the surface of the plasma-treated sample. The contact angle was also decreased following plasma treatment, indicating improved hydrophilicity of plasma-treated surfaces compared to the untreated disc. A significant increase in MC3T3E-1 cell attachment and proliferation was noted on plasma-treated samples as compared to untreated specimens. The results suggest that non-thermal atmospheric pressure nitrogen and air plasma treatments provide beneficial surface characteristics on HA/β-TCP scaffolds. - Highlights: ► Non-thermal plasma increased OH- and decreased C on biphasic scaffold. ► Non-thermal plasma had no effect on surface roughness. ► Non-thermal plasma resulted in hydrophilic surface. ► Non-thermal plasma resulted in better cell attachment and proliferation. ► Non-thermal plasma treatment on biphasic scaffold is useful for tissue engineering

Compound refractive X-ray lens

International Nuclear Information System (INIS)

Nygren, D.R.; Cahn, R.; Cederstrom, B.; Danielsson, M.; Vestlund, J.

2000-01-01

An apparatus and method are disclosed for focusing X-rays. In one embodiment, his invention is a commercial-grade compound refractive X-ray lens. The commercial-grade compound refractive X-ray lens includes a volume of low-Z material. The volume of low-Z material has a first surface which is adapted to receive X-rays of commercially-applicable power emitted from a commercial-grade X-ray source. The volume of low-Z material also has a second surface from which emerge the X-rays of commercially-applicable power which were received at the first surface. Additionally, the commercial-grade compound refractive X-ray lens includes a plurality of openings which are disposed between the first surface and the second surface. The plurality of openings are oriented such that the X-rays of commercially-applicable power which are received at the first surface, pass through the volume of low-Z material and through the plurality openings. In so doing, the X-rays which emerge from the second surface are refracted to a focal point

Compound refractive X-ray lens

Science.gov (United States)

Nygren, David R.; Cahn, Robert; Cederstrom, Bjorn; Danielsson, Mats; Vestlund, Jonas

2000-01-01

An apparatus and method for focusing X-rays. In one embodiment, his invention is a commercial-grade compound refractive X-ray lens. The commercial-grade compound refractive X-ray lens includes a volume of low-Z material. The volume of low-Z material has a first surface which is adapted to receive X-rays of commercially-applicable power emitted from a commercial-grade X-ray source. The volume of low-Z material also has a second surface from which emerge the X-rays of commercially-applicable power which were received at the first surface. Additionally, the commercial-grade compound refractive X-ray lens includes a plurality of openings which are disposed between the first surface and the second surface. The plurality of openings are oriented such that the X-rays of commercially-applicable power which are received at the first surface, pass through the volume of low-Z material and through the plurality openings. In so doing, the X-rays which emerge from the second surface are refracted to a focal point.

X-ray diffraction device comprising cooling medium connections provided on the x-ray tube

NARCIS (Netherlands)

1996-01-01

An X-ray diffraction device comprises a water-cooled X-ray tube which exhibits a line focus as well as, after rotation through 90 DEG , a point focus. Contrary to customary X-ray tubes, the cooling water is not supplied via the housing (12) in which the X-ray tube is mounted, but the cooling water

X-ray hot plasma diagnostics

International Nuclear Information System (INIS)

Cojocaru, E.

1984-11-01

X-ray plasma emission study is powerful diagnostic tool of hot plasmas. In this review article the main techniques of X-ray plasma emission measurement are shortly presented: X-ray spectrometry using absorbent filters, crystal and grating spectrometers, imaging techniques using pinhole cameras, X-ray microscopes and Fresnel zone plate cameras, X-ray plasma emission calorimetry. Advances in these techniques with examples for different hot plasma devices are also presentes. (author)

Chest X-Ray

Medline Plus

Full Text Available ... some concerns about chest x-rays. However, it’s important to consider the likelihood of benefit to your health. While a chest x-ray use a ... posted: How to Obtain and Share ...

Soft x-ray streak cameras

International Nuclear Information System (INIS)

Stradling, G.L.

1988-01-01

This paper is a discussion of the development and of the current state of the art in picosecond soft x-ray streak camera technology. Accomplishments from a number of institutions are discussed. X-ray streak cameras vary from standard visible streak camera designs in the use of an x-ray transmitting window and an x-ray sensitive photocathode. The spectral sensitivity range of these instruments includes portions of the near UV and extends from the subkilovolt x- ray region to several tens of kilovolts. Attendant challenges encountered in the design and use of x-ray streak cameras include the accommodation of high-voltage and vacuum requirements, as well as manipulation of a photocathode structure which is often fragile. The x-ray transmitting window is generally too fragile to withstand atmospheric pressure, necessitating active vacuum pumping and a vacuum line of sight to the x-ray signal source. Because of the difficulty of manipulating x-ray beams with conventional optics, as is done with visible light, the size of the photocathode sensing area, access to the front of the tube, the ability to insert the streak tube into a vacuum chamber and the capability to trigger the sweep with very short internal delay times are issues uniquely relevant to x-ray streak camera use. The physics of electron imaging may place more stringent limitations on the temporal and spatial resolution obtainable with x-ray photocathodes than with the visible counterpart. Other issues which are common to the entire streak camera community also concern the x-ray streak camera users and manufacturers

Portable X-ray fluorescence analyzer of high sensitivity using X-ray tube excitation

International Nuclear Information System (INIS)

Vatai, E.; Ando, L.

1982-01-01

A review of the three main methods of X-ray fluorescence analysis and their problems is given. The attainable accuracy and effectiveness of each method are discussed. The main properties of portable X-ray analyzers required by the industry are described. The results and experiences of R and D activities in ATOMKI (Debrecen, Hungary) for developing portable X-ray analyzers are presented. The only way for increasing the accuracy and decreasing the measuring time is the application of X-ray tube excitation instead of radioactive sources. The new ATOMKI equipment presently under construction and patenting uses X-ray tube excitation; it will increase the accuracy of concentration determination by one order of magnitude. (D.Gy.)

Constraining hydrostatic mass bias of galaxy clusters with high-resolution X-ray spectroscopy

Science.gov (United States)

Ota, Naomi; Nagai, Daisuke; Lau, Erwin T.

2018-04-01

Gas motions in galaxy clusters play important roles in determining the properties of the intracluster medium (ICM) and in the constraint of cosmological parameters via X-ray and Sunyaev-Zel'dovich effect observations of galaxy clusters. The Hitomi measurements of gas motions in the core of the Perseus Cluster have provided new insights into the physics in galaxy clusters. The XARM mission, equipped with the Resolve X-ray micro-calorimeter, will continue Hitomi's legacy by measuring ICM motions through Doppler shifting and broadening of emission lines in a larger number of galaxy clusters, and at larger radii. In this work, we investigate how well we can measure bulk and turbulent gas motions in the ICM with XARM, by analyzing mock XARM simulations of galaxy clusters extracted from cosmological hydrodynamic simulations. We assess how photon counts, spectral fitting methods, multiphase ICM structure, deprojections, and region selection affect the measurements of gas motions. We first show that XARM is capable of recovering the underlying spherically averaged turbulent and bulk velocity profiles for dynamically relaxed clusters to within ˜50% with a reasonable amount of photon counts in the X-ray emission lines. We also find that there are considerable azimuthal variations in the ICM velocities, where the velocities measured in a single azimuthal direction can significantly deviate from the true value even in dynamically relaxed systems. Such variation must be taken into account when interpreting data and developing observing strategies. We will discuss the prospect of using the upcoming XARM mission to measure non-thermal pressure and to correct for the hydrostatic mass bias of galaxy clusters. Our results are broadly applicable for future X-ray missions, such as Athena and Lynx.

Constraining hydrostatic mass bias of galaxy clusters with high-resolution X-ray spectroscopy

Science.gov (United States)

Ota, Naomi; Nagai, Daisuke; Lau, Erwin T.

2018-06-01

Gas motions in galaxy clusters play important roles in determining the properties of the intracluster medium (ICM) and in the constraint of cosmological parameters via X-ray and Sunyaev-Zel'dovich effect observations of galaxy clusters. The Hitomi measurements of gas motions in the core of the Perseus Cluster have provided new insights into the physics in galaxy clusters. The XARM mission, equipped with the Resolve X-ray micro-calorimeter, will continue Hitomi's legacy by measuring ICM motions through Doppler shifting and broadening of emission lines in a larger number of galaxy clusters, and at larger radii. In this work, we investigate how well we can measure bulk and turbulent gas motions in the ICM with XARM, by analyzing mock XARM simulations of galaxy clusters extracted from cosmological hydrodynamic simulations. We assess how photon counts, spectral fitting methods, multiphase ICM structure, deprojections, and region selection affect the measurements of gas motions. We first show that XARM is capable of recovering the underlying spherically averaged turbulent and bulk velocity profiles for dynamically relaxed clusters to within ˜50% with a reasonable amount of photon counts in the X-ray emission lines. We also find that there are considerable azimuthal variations in the ICM velocities, where the velocities measured in a single azimuthal direction can significantly deviate from the true value even in dynamically relaxed systems. Such variation must be taken into account when interpreting data and developing observing strategies. We will discuss the prospect of using the upcoming XARM mission to measure non-thermal pressure and to correct for the hydrostatic mass bias of galaxy clusters. Our results are broadly applicable for future X-ray missions, such as Athena and Lynx.

X ray Production. Chapter 5

Energy Technology Data Exchange (ETDEWEB)

Nowotny, R. [Medical University of Vienna, Vienna (Austria)

2014-09-15

The differential absorption of X rays in tissues and organs, owing to their atomic composition, is the basis for the various imaging methods used in diagnostic radiology. The principles in the production of X rays have remained the same since their discovery. However, much refinement has gone into the design of X ray tubes to achieve the performance required for today’s radiological examinations. In this chapter, an outline of the principles of X ray production and a characterization of the radiation output of X ray tubes will be given. The basic processes producing X rays are dealt with in Section 1.4.

X-ray apparatus

International Nuclear Information System (INIS)

Sell, L.J.

1981-01-01

A diagnostic x-ray device, readily convertible between conventional radiographic and tomographic operating modes, is described. An improved drive system interconnects and drives the x-ray source and the imaging device through coordinated movements for tomography

X-ray astronomy 2000: Wide field X-ray monitoring with lobster-eye telescopes

International Nuclear Information System (INIS)

Inneman, A.; Hudec, R.; Pina, L.; Gorenstein, P.

2001-01-01

The recently available first prototypes of innovative very wide field X-ray telescopes of Lobster-Eye type confirm the feasibility to develop such flight instruments in a near future. These devices are expected to allow very wide field (more than 1000 square degrees) monitoring of the sky in X-rays (up to 10 keV and perhaps even more) with faint limits. We will discuss the recent status of the development of very wide field X-ray telescopes as well as related scientific questions including expected major contributions such as monitoring and study of X-ray afterglows of Gamma Ray Bursts

A laboratory-based hard x-ray monochromator for high-resolution x-ray emission spectroscopy and x-ray absorption near edge structure measurements

Energy Technology Data Exchange (ETDEWEB)

Seidler, G. T., E-mail: seidler@uw.edu; Mortensen, D. R.; Remesnik, A. J.; Pacold, J. I.; Ball, N. A.; Barry, N.; Styczinski, M.; Hoidn, O. R. [Physics Department, University of Washington, Seattle, Washington 98195-1560 (United States)

2014-11-15

We report the development of a laboratory-based Rowland-circle monochromator that incorporates a low power x-ray (bremsstrahlung) tube source, a spherically bent crystal analyzer, and an energy-resolving solid-state detector. This relatively inexpensive, introductory level instrument achieves 1-eV energy resolution for photon energies of ∼5 keV to ∼10 keV while also demonstrating a net efficiency previously seen only in laboratory monochromators having much coarser energy resolution. Despite the use of only a compact, air-cooled 10 W x-ray tube, we find count rates for nonresonant x-ray emission spectroscopy comparable to those achieved at monochromatized spectroscopy beamlines at synchrotron light sources. For x-ray absorption near edge structure, the monochromatized flux is small (due to the use of a low-powered x-ray generator) but still useful for routine transmission-mode studies of concentrated samples. These results indicate that upgrading to a standard commercial high-power line-focused x-ray tube or rotating anode x-ray generator would result in monochromatized fluxes of order 10{sup 6}–10{sup 7} photons/s with no loss in energy resolution. This work establishes core technical capabilities for a rejuvenation of laboratory-based hard x-ray spectroscopies that could have special relevance for contemporary research on catalytic or electrical energy storage systems using transition-metal, lanthanide, or noble-metal active species.

Illumination system for X-ray lithography

International Nuclear Information System (INIS)

Buckley, W.D.

1989-01-01

An X-ray lithography system is described, comprising: a point source of X-Ray radiation; a wafer plane disposed in spaced relation to the point source of X-Ray radiation; a mask disposed between the point source of X-Ray radiation and the wafer plane whereby X-Ray radiation from the point source of X-ray radiation passes through the mask to the water plane; and X-Ray absorbent means mounted between the point source of X-Ray radiation and the wafer plane, the X-Ray absorbent means being of quadratically absorption from maximum absorption at the center to minimum absorption at the edge so as to have a radial absorption gradient profile to compensate for radial flux variation of the X-Ray radiation

An X-ray and optical study of the ultracompact X-ray binary A 1246-58

NARCIS (Netherlands)

in 't Zand, J.J.M.; Bassa, C.G.; Jonker, P.G.; Keek, L.; Verbunt, F.W.M.; Méndez, M.; Markwardt, C.B.

2008-01-01

Results are discussed of an X-ray and optical observation campaign of the low-mass X-ray binary A 1246-58 performed with instruments on Satellite per Astronomia X ("BeppoSAX"), the Rossi X-ray Timing Explorer (RXTE), the X-ray Multi-mirror Mission ("XMM-Newton"), the Swift mission, and the Very

X-ray - skeleton

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/003381.htm X-ray - skeleton To use the sharing features on this ... Degenerative bone conditions Osteomyelitis Risks There is low radiation exposure. X-rays machines are set to provide the smallest ...

Extremity x-ray

Science.gov (United States)

... page: //medlineplus.gov/ency/article/003461.htm Extremity x-ray To use the sharing features on this page, ... in the body Risks There is low-level radiation exposure. X-rays are monitored and regulated to provide the ...

Chest X-Ray

Medline Plus

Full Text Available ... X-ray Transcript Welcome to Radiology Info dot org! Hello, I’m Dr. Geoffrey Rubin, a radiologist ... about chest x-rays, visit Radiology Info dot org. Thank you for your time! Spotlight Recently posted: ...

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... The x-ray tube is connected to a flexible arm that is extended over the patient while an x-ray film holder or image recording plate is placed beneath the patient. top of page How does the procedure work? X-rays are a form of radiation like ...

X-ray Absorption Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Yano, Junko; Yachandra, Vittal K.

2009-07-09

This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

X-ray filtration apparatus

International Nuclear Information System (INIS)

Thompson, G.

1992-01-01

This invention relates to an X-ray shielding support device. In spite of considerable development in X-ray taking techniques, a need still exists for effective shielding, inter alia, to compensate for variations in the thickness, density and the absorption properties of the object being studied. By appropriate shielding, the X-ray image produced is of sufficient detail, contrast and intensity over its entire area to constitute a useful diagnostic aid. It is also desirable to subject the patient to the smallest possible X-ray dosage. 4 figs

Phase-contrast X-ray CT

Energy Technology Data Exchange (ETDEWEB)

Momose, Atsushi [Hitachi Ltd., Saitama (Japan). Advanced Research Laboratory; Takeda, Tohoru; Itai, Yuji

1995-12-01

Phase-contrast X-ray computed tomography (CT) enabling the observation of biological soft tissues without contrast enhancement has been developed. The X-ray phase shift caused by an object is measured and input to a standard CT reconstruction algorithm. A thousand times increase in the image sensitivity to soft tissues is achieved compared with the conventional CT using absorption contrast. This is because the X-ray phase shift cross section of light elements is about a thousand times larger than the absorption cross section. The phase shift is detected using an X-ray interferometer and computer analyses of interference patterns. Experiments were performed using a synchrotron X-ray source. Excellent image sensitivity is demonstrated in the observation of cancerous rabbit liver. The CT images distinguish cancer lesion from normal liver tissue and, moreover, visualize the pathological condition in the lesion. Although the X-ray energy employed and the present observation area size are not suitable for medical applications as they are, phase-contrast X-ray CT is promising for investigating the internal structure of soft tissue which is almost transparent for X-rays. The high sensitivity also provides the advantage of reducing X-ray doses. (author).

Symbiotic Stars in X-rays

Science.gov (United States)

Luna, G. J. M.; Sokoloski, J. L.; Mukai, K.; Nelson, T.

2014-01-01

Until recently, symbiotic binary systems in which a white dwarf accretes from a red giant were thought to be mainly a soft X-ray population. Here we describe the detection with the X-ray Telescope (XRT) on the Swift satellite of 9 white dwarf symbiotics that were not previously known to be X-ray sources and one that was previously detected as a supersoft X-ray source. The 9 new X-ray detections were the result of a survey of 41 symbiotic stars, and they increase the number of symbiotic stars known to be X-ray sources by approximately 30%. Swift/XRT detected all of the new X-ray sources at energies greater than 2 keV. Their X-ray spectra are consistent with thermal emission and fall naturally into three distinct groups. The first group contains those sources with a single, highly absorbed hard component, which we identify as probably coming from an accretion-disk boundary layer. The second group is composed of those sources with a single, soft X-ray spectral component, which likely arises in a region where low-velocity shocks produce X-ray emission, i.e. a colliding-wind region. The third group consists of those sources with both hard and soft X-ray spectral components. We also find that unlike in the optical, where rapid, stochastic brightness variations from the accretion disk typically are not seen, detectable UV flickering is a common property of symbiotic stars. Supporting our physical interpretation of the two X-ray spectral components, simultaneous Swift UV photometry shows that symbiotic stars with harder X-ray emission tend to have stronger UV flickering, which is usually associated with accretion through a disk. To place these new observations in the context of previous work on X-ray emission from symbiotic stars, we modified and extended the alpha/beta/gamma classification scheme for symbiotic-star X-ray spectra that was introduced by Muerset et al. based upon observations with the ROSAT satellite, to include a new sigma classification for sources with

X-ray apparatus

International Nuclear Information System (INIS)

Bernstein, S.; Stagg, L.; Lambert, T.W.; Griswa, P.J.

1976-01-01

A patient support system for X-ray equipment in arteriographic studies of the heart is described in detail. The support system has been designed to overcome many of the practical problems encountered in using previous types of arteriographic X-ray equipment. The support system is capable of horizontal movement and, by a series of shafts attached to the main support system, the X-ray source and image intensifier or detector may be rotated through the same angle. The system is highly flexible and details are given of several possible operational modes. (U.K.)

Comparative study of radiation dose between digital panoramic X-ray unit and general panoramic X-ray unit

International Nuclear Information System (INIS)

Li Qingshan; Duan Tao; Wang Xiaoyun; Zhao Li; Dong Jian; Wei Lei

2010-01-01

Objective: To compare the actual dose of patients who receive the same medical practice by either digital panoramic X-ray unit and general panoramic X-ray unit and give evidence for better selection of oral X-ray examination method. Methods: Round sheet lithium fluoride (LiF) thermoluminescent dosimeters (TLD) were used. The experiment was divided into natural background contrast group, general panoramic X-ray children group, general panoramic X-ray adults group, digital panoramic X-ray children group and digital panoramic X-ray adults group. The dosimeter of natural background radiation was placed at the office of the doctor, the dosimeters of general panoramic X-ray children group and general panoramic X-ray adults group were irradiated by different conditions according to the clinical application of panoramic X-ray to children and adults, the dosimeters of digital panoramic X-ray children group and digital panoramic X-ray adults group were irradiated by different conditions according to the clinical application of digital panoramic X-ray to children and adults. The thermoluminescent dosimeter was used to count and calculate the exposure doses in various groups. Results: The dose of children exposed in general panoramic X-ray unit was 1.28 times of that in digital panoramic X-ray unit, there was significant difference (t=6.904, P<0.01). The dose of adults exposed in general panoramic X-ray unit was 1.55 times of that in the digital panoramic X-ray unit, there also was significant difference (t=-11.514. P< 0.01). Conclusion: The digital panoramic X-ray unit can reduce the dose of patients, so the digital panoramic X-ray unit should be used as far as possible. (authors)

Fundamental limitations of non-thermal plasma processing for internal combustion engine NOx control

International Nuclear Information System (INIS)

Penetrante, B.M.

1993-01-01

This paper discusses the physics and chemistry of non-thermal plasma processing for post-combustion NO x control in internal combustion engines. A comparison of electron beam and electrical discharge processing is made regarding their power consumption, radical production, NO x removal mechanisms, and by product formation. Can non-thermal deNO x operate efficiently without additives or catalysts? How much electrical power does it cost to operate? What are the by-products of the process? This paper addresses these fundamental issues based on an analysis of the electron-molecule processes and chemical kinetics

Nanoparticle-Assisted Scanning Focusing X-Ray Therapy with Needle Beam X Rays.

Science.gov (United States)

Davidson, R Andrew; Guo, Ting

2016-01-01

In this work, we show a new therapeutic approach using 40-120 keV X rays to deliver a radiation dose at the isocenter located many centimeters below the skin surface several hundred times greater than at the skin and how this dose enhancement can be augmented with nanomaterials to create several thousand-fold total dose enhancement effect. This novel approach employs a needle X-ray beam directed at the isocenter centimeters deep in the body while continuously scanning the beam to cover a large solid angle without overlapping at the skin. A Monte Carlo method was developed to simulate an X-ray dose delivered to the isocenter filled with X-ray absorbing and catalytic nanoparticles in a water phantom. An experimental apparatus consisting of a moving plastic phantom irradiated with a stationary 1 mm needle X-ray beam was built to test the theoretical predictions. X-ray films were used to characterize the dose profiles of the scanning X-ray apparatus. Through this work, it was determined that the X-ray dose delivered to the isocenter in a treatment voxel (t-voxel) underneath a 5 cm deep high-density polyethylene (HDPE) phantom was 295 ± 48 times greater than the surface dose. This measured value was in good agreement with the theoretical predicted value of 339-fold. Adding X-ray-absorbing nanoparticles, catalytic nanoparticles or both into the t-voxel can further augment the dose enhancement. For example, we predicted that adding 1 weight percentage (wp) of gold into water could increase the effective dose delivered to the target by onefold. Dose enhancement using 1 mm X-ray beam could reach about 1,600-fold in the t-voxel when 7.5 wp of 88 nm diameter silica-covered gold nanoparticles were added, which we showed in a previously published study can create a dose enhancement of 5.5 ± 0.46-fold without scanning focusing enhancement. Based on the experimental data from that study, mixing 0.02 wp 2.5 nm diameter small tetrakis hydroxymethyl phosphonium chloride (THPC

Deep optical observations of the γ-ray pulsar J0357+3205

Science.gov (United States)

Kirichenko, A.; Danilenko, A.; Shibanov, Yu.; Shternin, P.; Zharikov, S.; Zyuzin, D.

2014-04-01

Context. A middle-aged radio-quiet pulsar J0357+3205 was discovered in gamma rays with Fermi and later in X-rays with Chandra and XMM-Newton observatories. It produces an unusual thermally emitting pulsar wind nebula that is observed in X-rays. Aims: Deep optical observations were obtained to search for the pulsar optical counterpart and its nebula using the Gran Telescopio Canarias (GTC). Methods: The direct imaging mode in the Sloan g' band was used. Archival X-ray data were reanalysed and compared with the optical data. Results: No pulsar optical counterpart was detected down to g'≥slant 28.1m. No pulsar nebula was identified in the optical either. We confirm early results that the X-ray spectrum of the pulsar consists of a nonthermal power-law component of the pulsar magnetospheric origin dominating at high energies and a soft thermal component from the neutron star surface. Using magnetised, partially ionised hydrogen atmosphere models in X-ray spectral fits, we found that the thermal component can come from the entire surface of the cooling neutron star with a temperature of 36+8-6 eV, making it one of the coldest among cooling neutron stars known. The surface temperature agrees with the standard neutron star cooling scenario. The optical upper limit does not put any additional constraints on the thermal component, however it does imply a strong spectral break for the nonthermal component between the optical and X-rays as is observed in other middle-aged pulsars. Conclusions: The thermal emission from the entire surface of the neutron star very likely dominates the nonthermal emission in the UV range. Observations of PSR J0357+3205 in this range are promising to put more stringent constraints on its thermal properties. Based on observations made with the Gran Telescopio Canarias (GTC), instaled in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, in the island of La Palma under Programme GTC3-12BMEX

X-ray astronomy

International Nuclear Information System (INIS)

Narayanan, M.S.

1976-01-01

The deployment of detectors outside the deleterious effects of the atmosphere by sending them in space vehicles, has been explained. This has thrown open the entire spectrum of the electromagnetic and particle radiation to direct observations, thus enlarging the vistas of the field of astronomy and astrophysics. The discovery of strong emitters of X-rays such as SCO X-1, NorX-2, transient sources such as Cen X-2, Cen X-4, Cen X-1, Supernova remnants Tan X-1, etc., are reported. The background of the X-ray spectrum as measured during two rocket flights over Thumba, India is presented. (K.B.)

Application of X-ray CCD camera in X-ray spot diagnosis of rod-pinch diode

International Nuclear Information System (INIS)

Song Yan; Zhou Ming; Song Guzhou; Ma Jiming; Duan Baojun; Han Changcai; Yao Zhiming

2015-01-01

The pinhole imaging technique is widely used in the measurement of X-ray spot of rod-pinch diode. The X-ray CCD camera, which was composed of film, fiber optic taper and CCD camera, was employed to replace the imaging system based on scintillator, lens and CCD camera in the diagnosis of X-ray spot. The resolution of the X-ray CCD camera was studied. The resolution is restricted by the film and is 5 lp/mm in the test with Pb resolution chart. The frequency is 1.5 lp/mm when the MTF is 0.5 in the test with edge image. The resolution tests indicate that the X-ray CCD camera can meet the requirement of the diagnosis of X-ray spot whose scale is about 1.5 mm when the pinhole imaging magnification is 0.5. At last, the image of X-ray spot was gained and the restoration was implemented in the diagnosis of X-ray spot of rod-pinch diode. (authors)

Scintillating ribbon x-ray detector

International Nuclear Information System (INIS)

Kinchen, B.E.; Rogers, A.

1995-01-01

A patent in the early 1970's by Aerojet Corporation in Sacramento, CA put forth the idea of using an array of scintillating fibers for x-ray detection and imaging. In about 1975, Pratt and Whitney Aircraft in East Hartford, CT designed and manufactured an imaging system based on the patent. The device was 1.75 in thick in the direction of the x-ray beam and about 4 in. by 4 in. square. The device was used with a 8 MeV x-ray source to image and measure internal clearances within operating aircraft, gas turbines engines. There are significant advantages of fiber optic detectors in x-ray detection. However, the advantages are often outweighed by the disadvantages. Two of the advantages of scintillating fiber optic x-ray detectors are: (1) high limiting spatial frequency -- between 20 and 25 lp/mm; and (2) excellent x-ray stopping power -- they can be made thick and retain spatial resolution. In traditional fiber optic detectors the x-rays are oriented parallel to the long axis of the fiber. For the scintillating ribbon x-ray sensor, the x-rays are oriented normal to the fiber long axis. This ribbon sensor technique has a number of advantages over the two current radiographic techniques digital x-radiography and x-ray film: The main advantage the ribbon has is size and shape. It can be as thin as 0.05 in., virtually any width or length, and flexible. Once positioned in a given location, 20 to 100 square inches of the object being inspected can be imaged with a single x-ray beam sweep. It is clear that conventional digital cameras do not lend themselves to placement between walls of aircraft structures or similar items requiring x-ray inspections. A prototype scintillating ribbon x-ray sensor has been fabricated and tested by Synergistic Detector Designs. Images were acquired on corrosion test panels of aluminum fabricated by Iowa State University

Center for X-Ray Optics, 1992

International Nuclear Information System (INIS)

1993-08-01

This report discusses the following topics: Center for X-Ray Optics; Soft X-Ray Imaging wit Zone Plate Lenses; Biological X-Ray microscopy; Extreme Ultraviolet Lithography for Nanoelectronic Pattern Transfer; Multilayer Reflective Optics; EUV/Soft X-ray Reflectometer; Photoemission Microscopy with Reflective Optics; Spectroscopy with Soft X-Rays; Hard X-Ray Microprobe; Coronary Angiography; and Atomic Scattering Factors

JEM-X: The X-ray monitor on INTEGRAL

DEFF Research Database (Denmark)

Budtz-Jørgensen, Carl; Lund, Niels; Westergaard, Niels Jørgen Stenfeldt

2004-01-01

The INTEGRAL X-ray monitor, JEM-X, (together with the two gamma ray instruments, SPI and IBIS) provides simultaneous imaging with arcminute angular resolution in the 3-35 keV band. The good angular resolution and low energy response of JEM-X plays an important role in the detection and identifica......The INTEGRAL X-ray monitor, JEM-X, (together with the two gamma ray instruments, SPI and IBIS) provides simultaneous imaging with arcminute angular resolution in the 3-35 keV band. The good angular resolution and low energy response of JEM-X plays an important role in the detection...

X ray spectra of X Per. [oso-8 observations

Science.gov (United States)

Becker, R. H.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Robinson-Saba, J.; Serlemitsos, P. J.; Swank, J. H.

1978-01-01

The cosmic X-ray spectroscopy experiment on OSO-8 observed X Per for twenty days during two observations in Feb. 1976 and Feb. 1977. The spectrum of X Per varies in phase with its 13.9 min period, hardening significantly at X-ray minimum. Unlike other X-ray binary pulsar spectra, X Per's spectra do not exhibit iron line emission or strong absorption features. The data show no evidence for a 22 hour periodicity in the X-ray intensity of X Per. These results indicate that the X-ray emission from X Per may be originating from a neutron star in a low density region far from the optically identified Be star.

JEM-X: The X-ray monitor on INTEGRAL

DEFF Research Database (Denmark)

Lund, Niels; Budtz-Jørgensen, Carl; Westergaard, Niels Jørgen Stenfeldt

1999-01-01

and identification of gamma ray sources as well as in the analysis and scientific interpretation of the combined X-ray and gamma ray data. JEM-X is a coded aperture X-ray telescope consisting of two identical detectors. Each detector has a sensitive area of 500 cm(2), and views the sky (6.6 deg FOV, FWHM) through...

Accelerator-driven X-ray Sources

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-11-09

After an introduction which mentions x-ray tubes and storage rings and gives a brief review of special relativity, the subject is treated under the following topics and subtopics: synchrotron radiation (bending magnet radiation, wiggler radiation, undulator radiation, brightness and brilliance definition, synchrotron radiation facilities), x-ray free-electron lasers (linac-driven X-ray FEL, FEL interactions, self-amplified spontaneous emission (SASE), SASE self-seeding, fourth-generation light source facilities), and other X-ray sources (energy recovery linacs, Inverse Compton scattering, laser wakefield accelerator driven X-ray sources. In summary, accelerator-based light sources cover the entire electromagnetic spectrum. Synchrotron radiation (bending magnet, wiggler and undulator radiation) has unique properties that can be tailored to the users’ needs: bending magnet and wiggler radiation is broadband, undulator radiation has narrow spectral lines. X-ray FELs are the brightest coherent X-ray sources with high photon flux, femtosecond pulses, full transverse coherence, partial temporal coherence (SASE), and narrow spectral lines with seeding techniques. New developments in electron accelerators and radiation production can potentially lead to more compact sources of coherent X-rays.

Effects of X-Ray Dose On Rhizosphere Studies Using X-Ray Computed Tomography

Science.gov (United States)

Zappala, Susan; Helliwell, Jonathan R.; Tracy, Saoirse R.; Mairhofer, Stefan; Sturrock, Craig J.; Pridmore, Tony; Bennett, Malcolm; Mooney, Sacha J.

2013-01-01

X-ray Computed Tomography (CT) is a non-destructive imaging technique originally designed for diagnostic medicine, which was adopted for rhizosphere and soil science applications in the early 1980s. X-ray CT enables researchers to simultaneously visualise and quantify the heterogeneous soil matrix of mineral grains, organic matter, air-filled pores and water-filled pores. Additionally, X-ray CT allows visualisation of plant roots in situ without the need for traditional invasive methods such as root washing. However, one routinely unreported aspect of X-ray CT is the potential effect of X-ray dose on the soil-borne microorganisms and plants in rhizosphere investigations. Here we aimed to i) highlight the need for more consistent reporting of X-ray CT parameters for dose to sample, ii) to provide an overview of previously reported impacts of X-rays on soil microorganisms and plant roots and iii) present new data investigating the response of plant roots and microbial communities to X-ray exposure. Fewer than 5% of the 126 publications included in the literature review contained sufficient information to calculate dose and only 2.4% of the publications explicitly state an estimate of dose received by each sample. We conducted a study involving rice roots growing in soil, observing no significant difference between the numbers of root tips, root volume and total root length in scanned versus unscanned samples. In parallel, a soil microbe experiment scanning samples over a total of 24 weeks observed no significant difference between the scanned and unscanned microbial biomass values. We conclude from the literature review and our own experiments that X-ray CT does not impact plant growth or soil microbial populations when employing a low level of dose (<30 Gy). However, the call for higher throughput X-ray CT means that doses that biological samples receive are likely to increase and thus should be closely monitored. PMID:23840640

Synchrotron x-ray fluorescence and extended x-ray absorption fine structure analysis

International Nuclear Information System (INIS)

Chen, J.R.; Gordon, B.M.; Hanson, A.L.; Jones, K.W.; Kraner, H.W.; Chao, E.C.T.; Minkin, J.A.

1984-01-01

The advent of dedicated synchrotron radiation sources has led to a significant increase in activity in many areas of science dealing with the interaction of x-rays with matter. Synchrotron radiation provides intense, linearly polarized, naturally collimated, continuously tunable photon beams, which are used to determine not only the elemental composition of a complex, polyatomic, dilute material but also the chemical form of the elements with improved accuracy. Examples of the application of synchrotron radiation include experiments in synchrotron x-ray fluorescence (SXRF) analysis and extended x-ray absorption fine structure (EXAFS) analysis. New synchrotron radiation x-ray microprobes for elemental analysis in the parts per billion range are under construction at several laboratories. 76 references, 24 figures

X-Rays, Pregnancy and You

Science.gov (United States)

... Emitting Products and Procedures Medical Imaging Medical X-ray Imaging X-Rays, Pregnancy and You Share Tweet Linkedin Pin it ... the decision with your doctor. What Kind of X-Rays Can Affect the Unborn Child? During most x- ...

Application of non-thermal plasmas to pollution control

International Nuclear Information System (INIS)

Penetrante, B.M.; Vogtlin, G.E.; Bardsley, J.N.; Vitello, P.A.; Wallman, P.H.

1993-01-01

Non-thermal plasma techniques can be used to destroy many types of hazardous molecules. They are particularly efficient when the toxic materials are present in very small concentrations. This paper discusses three particular applications of non-thermal plasmas: (1) decomposition of hydrogen sulfide (H 2 S), (2) removal of trichloroethylene (TCE), and (3) removal of nitric oxides (NO x ) Emphasis is placed on the energy cost for implementing the decomposition or removal of these pollutants. Some of the factors affecting the energy cost are discussed. We discuss in detail our work at LLNL on pulsed plasma processing for the treatment of NO x in diesel engine exhaust. Our results suggest that our plasma reactor can remove up to 70% of NO x with relatively high initial concentrations (up to 500 ppM) at a power consumption cost of 2.5% for an engine with an output of 14 kill and an exhaust gas flow rate of 1200 liters per minute

Stellar X-ray sources

International Nuclear Information System (INIS)

Katz, J.I.; Washington Univ., St. Louis, MO

1988-01-01

I Review some of the salient accomplishments of X-rap studies of compact objects. Progress in this field has closely followed the improvement of observational methods, particularly in angular resolution and duration of exposure. Luminous compact X-ray sources are accreting neutron stars or black holes. Accreting neutron stars may have characteristic temporal signatures, but the only way to establish that an X-ray source is a black hole is to measure its mass. A rough phenomenological theory is succesful, but the transport of angular momentum in accretion flows is not onderstood. A number of interesting complications have been observed, including precessing accretion discs, X-ray bursts, and the acceleration of jets in SS433. Many puzzles remain unsolved, including the excitation of disc precession, the nature of the enigmatic A- and gamma-ray source Cyg X-3, the mechanism by which slowly spinning accreting neutron stars lose angular momentum, and the superabundance of X-ray sources in globular clusters. 41 refs.; 5 figs

Evidence for quiescent synchrotron emission in the black hole X-ray transient Swift J1357.2–0933

Directory of Open Access Journals (Sweden)

Shahbaz T.

2013-12-01

Full Text Available We present high time-resolution optical and infrared observations of the edge-on black hole X-ray transient Swift J1357.2-0933. Our data taken in 2012 shows the system to be at its pre-outburst magnitude and so the system is in quiescence. In contrast to other X-ray transients, the quiescent light curves of Swift J1357.2-0933 do not show the secondary star’s ellipsoidal modulation. The optical and infrared light curves is dominated by variability with an optical fractional rms of about 20 per cent, much larger than what is observed in other systems. The quiescent ultraviolet to mid-IR spectral energy distribution in quiescence is dominated by a nonthermal component with a power–law index of −1.4, (the broad-band rms SED has a similar index which arises from optically thin synchrotron emission from a jet; the lack of a peak in the spectral energy distribution rules out advection-dominated models (based on [19].

Toward Adaptive X-Ray Telescopes

Science.gov (United States)

O'Dell, Stephen L.; Atkins, Carolyn; Button, Tim W.; Cotroneo, Vincenzo; Davis, William N.; Doel, Peer; Feldman, Charlotte H.; Freeman, Mark D.; Gubarev, Mikhail V.; Kolodziejczak, Jeffrey J.;

Charge collection and absorption-limited x-ray sensitivity of pixellated x-ray detectors

International Nuclear Information System (INIS)

Kabir, M. Zahangir; Kasap, S.O.

2004-01-01

The charge collection and absorption-limited x-ray sensitivity of a direct conversion pixellated x-ray detector operating in the presence of deep trapping of charge carriers is calculated using the Shockley-Ramo theorem and the weighting potential of the individual pixel. The sensitivity of a pixellated x-ray detector is analyzed in terms of normalized parameters; (a) the normalized x-ray absorption depth (absorption depth/photoconductor thickness), (b) normalized pixel width (pixel size/thickness), and (c) normalized carrier schubwegs (schubweg/thickness). The charge collection and absorption-limited sensitivity of pixellated x-ray detectors mainly depends on the transport properties (mobility and lifetime) of the charges that move towards the pixel electrodes and the extent of dependence increases with decreasing normalized pixel width. The x-ray sensitivity of smaller pixels may be higher or lower than that of larger pixels depending on the rate of electron and hole trapping and the bias polarity. The sensitivity of pixellated detectors can be improved by ensuring that the carrier with the higher mobility-lifetime product is drifted towards the pixel electrodes

X-ray interferometers

International Nuclear Information System (INIS)

Franks, A.

1980-01-01

An improved type of amplitude-division x-ray interferometer is described. The wavelength at which the interferometer can operate is variable, allowing the instrument to be used to measure x-ray wavelength, and the angle of inclination is variable for sample investigation. (U.K.)

X-ray lasers

CERN Document Server

Elton, Raymond C

2012-01-01

The first in its field, this book is both an introduction to x-ray lasers and a how-to guide for specialists. It provides new entrants and others interested in the field with a comprehensive overview and describes useful examples of analysis and experiments as background and guidance for researchers undertaking new laser designs. In one succinct volume, X-Ray Lasers collects the knowledge and experience gained in two decades of x-ray laser development and conveys the exciting challenges and possibilities still to come._Add on for longer version of blurb_M>The reader is first introduced

Topological X-Rays Revisited

Science.gov (United States)

Lynch, Mark

2012-01-01

We continue our study of topological X-rays begun in Lynch ["Topological X-rays and MRI's," iJMEST 33(3) (2002), pp. 389-392]. We modify our definition of a topological magnetic resonance imaging and give an affirmative answer to the question posed there: Can we identify a closed set in a box by defining X-rays to probe the interior and without…

Systematic search for very-high-energy gamma-ray emission from bow shocks of runaway stars

Science.gov (United States)

H.E.S.S. Collaboration; Abdalla, H.; Abramowski, A.; Aharonian, F.; Ait Benkhali, F.; Akhperjanian, A. G.; Andersson, T.; Angüner, E. O.; Arakawa, M.; Arrieta, M.; Aubert, P.; Backes, M.; Balzer, A.; Barnard, M.; Becherini, Y.; Becker Tjus, J.; Berge, D.; Bernhard, S.; Bernlöhr, K.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Bregeon, J.; Brun, F.; Brun, P.; Bryan, M.; Büchele, M.; Bulik, T.; Capasso, M.; Carr, J.; Casanova, S.; Cerruti, M.; Chakraborty, N.; Chalme-Calvet, R.; Chaves, R. C. G.; Chen, A.; Chevalier, J.; Chrétien, M.; Coffaro, M.; Colafrancesco, S.; Cologna, G.; Condon, B.; Conrad, J.; Cui, Y.; Davids, I. D.; Decock, J.; Degrange, B.; Deil, C.; Devin, J.; deWilt, P.; Dirson, L.; Djannati-Ataï, A.; Domainko, W.; Donath, A.; Drury, L. O.'C.; Dutson, K.; Dyks, J.; Edwards, T.; Egberts, K.; Eger, P.; Ernenwein, J.-P.; Eschbach, S.; Farnier, C.; Fegan, S.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Funk, S.; Füßling, M.; Gabici, S.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J. F.; Gottschall, D.; Goyal, A.; Grondin, M.-H.; Hahn, J.; Haupt, M.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holler, M.; Horns, D.; Ivascenko, A.; Iwasaki, H.; Jacholkowska, A.; Jamrozy, M.; Janiak, M.; Jankowsky, D.; Jankowsky, F.; Jingo, M.; Jogler, T.; Jouvin, L.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Katsuragawa, M.; Katz, U.; Kerszberg, D.; Khangulyan, D.; Khélifi, B.; Kieffer, M.; King, J.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Krakau, S.; Kraus, M.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lees, J.-P.; Lefaucheur, J.; Lefranc, V.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leser, E.; Lohse, T.; Lorentz, M.; Liu, R.; López-Coto, R.; Lypova, I.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Mohrmann, L.; Morå, K.; Moulin, E.; Murach, T.; Nakashima, S.; de Naurois, M.; Niederwanger, F.; Niemiec, J.; Oakes, L.; O'Brien, P.; Odaka, H.; Öttl, S.; Ohm, S.; Ostrowski, M.; Oya, I.; Padovani, M.; Panter, M.; Parsons, R. D.; Pekeur, N. W.; Pelletier, G.; Perennes, C.; Petrucci, P.-O.; Peyaud, B.; Piel, Q.; Pita, S.; Poon, H.; Prokhorov, D.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Richter, S.; Rieger, F.; Romoli, C.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Saito, S.; Salek, D.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwemmer, S.; Seglar-Arroyo, M.; Settimo, M.; Seyffert, A. S.; Shafi, N.; Shilon, I.; Simoni, R.; Sol, H.; Spanier, F.; Spengler, G.; Spies, F.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stycz, K.; Sushch, I.; Takahashi, T.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tibaldo, L.; Tiziani, D.; Tluczykont, M.; Trichard, C.; Tsuji, N.; Tuffs, R.; Uchiyama, Y.; van der Walt, D. J.; van Eldik, C.; van Rensburg, C.; van Soelen, B.; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Vuillaume, T.; Wadiasingh, Z.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zabalza, V.; Zaborov, D.; Zacharias, M.; Zanin, R.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Ziegler, A.; Żywucka, N.

2018-04-01

Context. Runaway stars form bow shocks by ploughing through the interstellar medium at supersonic speeds and are promising sources of non-thermal emission of photons. One of these objects has been found to emit non-thermal radiation in the radio band. This triggered the development of theoretical models predicting non-thermal photons from radio up to very-high-energy (VHE, E ≥ 0.1 TeV) gamma rays. Subsequently, one bow shock was also detected in X-ray observations. However, the data did not allow discrimination between a hot thermal and a non-thermal origin. Further observations of different candidates at X-ray energies showed no evidence for emission at the position of the bow shocks either. A systematic search in the Fermi-LAT energy regime resulted in flux upper limits for 27 candidates listed in the E-BOSS catalogue. Aim. Here we perform the first systematic search for VHE gamma-ray emission from bow shocks of runaway stars. Methods: Using all available archival H.E.S.S. data we search for very-high-energy gamma-ray emission at the positions of bow shock candidates listed in the second E-BOSS catalogue release. Out of the 73 bow shock candidates in this catalogue, 32 have been observed with H.E.S.S. Results: None of the observed 32 bow shock candidates in this population study show significant emission in the H.E.S.S. energy range. Therefore, flux upper limits are calculated in five energy bins and the fraction of the kinetic wind power that is converted into VHE gamma rays is constrained. Conclusions: Emission from stellar bow shocks is not detected in the energy range between 0.14 and 18 TeV.The resulting upper limits constrain the level of VHE gamma-ray emission from these objects down to 0.1-1% of the kinetic wind energy.

X-ray tube

International Nuclear Information System (INIS)

Webley, R.S.

1975-01-01

The object of the invention described is to provide an X-ray tube providing a scanned X-ray output which does not require a scanned electron beam. This is obtained by an X-ray tube including an anode which is rotatable about an axis, and a source of a beam of energy, for example an electron beam, arranged to impinge on a surface of the anode to generate X-radiation substantially at the region of incidence on the anode surface. The anode is rotatable about the axis to move the region of incidence over the surface. The anode is so shaped that the rotation causes the region of incidence to move in a predetermined manner relative to fixed parts of the tube so that the generated X-radiation is scanned in a predetermined manner relative to the tube. (UK)

Studying The Spectral Shape And The X-ray/uv Variability Of Active Galactic Nuclei With Data From Swift And Xmm Archives

Science.gov (United States)

Turriziani, Sara

2011-01-01

Many efforts have been made in understanding the underlying origin of variability in Active Galactic Nuclei (AGN), but at present they could give still no conclusive answers. Since a deeper knowledge of variability will enable to understand better the accretion process onto supermassive black holes, I built the first ensemble struction function analysis of the X-ray variability of samples of quasars with data from Swift and XMM-Newton archives in order to study the average properties of their variability. Moreover, it is known that UV and X-ray luminosities of quasars are correlated and recent studies quantified this relation across 5 orders of magnitude. In this context, I presents results on the X-ray/UV ratio from simultaneous observations in UV and X-ray bands of a sample of quasars with data from XMM-Newton archive. Lastly, I will present a complete sample of Swift/SDSS faint blazars and other non-thermal dominated AGNs. I used this sample to calculate the general statistical properties of faint blazars and radio galaxies and in particular their Radio LogN-LogS with fluxes down to 10 mJy, in order to gain knowledge on the contribution to Cosmic Microwave Background (CMB) and gamma-ray background radiation from the faint tail of the radio population. I acknowledge financial support through Grant ASI I/088/06/0.

Upsurge of X-ray astronomy 230-

International Nuclear Information System (INIS)

Hudec, D.R.

1978-01-01

Instruments are described used for X-ray astronomy, namely X-ray detectors and X-ray telescopes. Unlike telescopes, the detectors do not comprise X-ray optics. A survey is given of the results obtained in solar and stellar X-ray astronomy and hypotheses are submitted on the origin of X radiation in the interstellar space. (J.B.)

Review of X-ray Tomography and X-ray Fluorescence Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Shear, Trevor A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-03-16

This literature review will focus on both laboratory and synchrotron based X-ray tomography of materials and highlight the inner workings of these instruments. X-ray fluorescence spectroscopy will also be reviewed and applications of the tandem use of these techniques will be explored. The real world application of these techniques during the internship will also be discussed.

Exploring the X-Ray Universe

Science.gov (United States)

Seward, Frederick D.; Charles, Philip A.

1995-11-01

Exploring the X-Ray Universe describes the view of the stars and galaxies that is obtained through X-ray telescopes. X-rays, which are invisible to human sight, are created in the cores of active galaxies, in cataclysmic stellar explosions, and in streams of gas expelled by the Sun and stars. The window on the heavens used by the X-ray astronomers shows the great drama of cosmic violence on the grandest scale. This account of X-ray astronomy incorporates the latest findings from several observatories operating in space. These include the Einstein Observatory operated by NASA, and the EXOSAT satellite of the European Space Agency. The book covers the entire field, with chapters on stars, supernova remnants, normal and active galaxies, clusters of galaxies, the diffuse X-ray background, and much more. The authors review basic principles, include the necessary historical background, and explain exactly what we know from X-ray observations of the Universe.

X-ray imaging system

International Nuclear Information System (INIS)

Houston, J.M.

1980-01-01

A novel, high-speed apparatus for use in X-ray computerised tomography is described in detail. It consists of a semi-circular array of X-ray sources, collimators and an ion chamber array for detection of the X-rays. The X-ray sources may be pulsed in salvos such that the corresponding detectors in the array are only illuminated by one source. The use of computer controlled salvos speeds up the image processing by at least a factor of two. The ion chamber array is designed to have a constant detection efficiency for varying angles of X-ray incidence. A detailed description of the detector construction and suggested gaseous fillings are given. It is claimed that the present tomographic system allows fast and accurate imaging of internal body organs and is insensitive to the blurring effects which motion of these organs tends to produce. (UK)

Femtosecond X-ray magnetic circular dichroism absorption spectroscopy at an X-ray free electron laser

Energy Technology Data Exchange (ETDEWEB)

Higley, Daniel J., E-mail: dhigley@stanford.edu; Yuan, Edwin [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Hirsch, Konstantin; Dakovski, Georgi L.; Jal, Emmanuelle; Lutman, Alberto A.; Coslovich, Giacomo; Hart, Philip; Hoffmann, Matthias C.; Mitra, Ankush; Moeller, Stefan; Ohldag, Hendrik; Seaberg, Matthew; Stöhr, Joachim; Nuhn, Heinz-Dieter; Reid, Alex H.; Dürr, Hermann A.; Schlotter, William F. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Liu, Tianmin; MacArthur, James P. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Department of Physics, Stanford University, Stanford, California 94305 (United States); and others

2016-03-15

X-ray magnetic circular dichroism spectroscopy using an X-ray free electron laser is demonstrated with spectra over the Fe L{sub 3,2}-edges. The high brightness of the X-ray free electron laser combined with high accuracy detection of incident and transmitted X-rays enables ultrafast X-ray magnetic circular dichroism studies of unprecedented sensitivity. This new capability is applied to a study of all-optical magnetic switching dynamics of Fe and Gd magnetic sublattices in a GdFeCo thin film above its magnetization compensation temperature.

Distortion of absorption-line velocity curves due to x-ray heating in x-ray binaries

International Nuclear Information System (INIS)

Milgrom, M.

1976-01-01

The effects of X-ray heating on the measured absorption line velocities, in X-ray binaries with low X-rays to optical luminosities ratio are considered. These effects may be appreciable even for such binaries where the effect of X-ray heating on the light-curve is negligible. The effects are studied qualitatively and suggest possible ways to partially eliminate the systematic errors introduced by them. The individual systems Cyg x-1 and SMC x-1 are treated and the results of numerical calculations are presented for them. For Cyg x-1 it is found that the effect is detectable during the X-ray 'high' state in all regions of the spectrum. During the 'low' state it may be important in the red region of the spectrum. The results for the case in which soft X-ray fluxes (E < or approximately .4 keV, suggested by theoretical models) are present are also given. For SMC x-1 a strong effect for Hα, Hβ, Hγ had been found. This effect may be responsible for the observed variable velocity curve. We also find for SMC x-1 that the average X-ray intensity falling on the primary must be considerably smaller than what is derived from the detected flux, or else the effect is too large. (author)

X-ray generation by femtosecond laser pulses and its application to soft X-ray imaging microscope

International Nuclear Information System (INIS)

Ikeda, Kenichi; Kotaki, Hideyuki; Nakajima, Kazuhisa

2002-01-01

We have developed laser-produced plasma X-ray sources using femtosecond laser pulses at 10Hz repetition rate in a table-top size in order to investigate basic mechanism of X-ray emission from laser-matter interactions and its application to a X-ray microscope. In a soft X-ray region over 5 nm wavelength, laser-plasma X-ray emission from a solid target achieved an intense flux of photons of the order of 1011 photons/rad per pulse with duration of a few 100 ps, which is intense enough to make a clear imaging in a short time exposure. As an application of laser-produced plasma X-ray source, we have developed a soft X-ray imaging microscope operating in the wavelength range around 14 nm. The microscope consists of a cylindrically ellipsoidal condenser mirror and a Schwarzshird objective mirror with highly-reflective multilayers. We report preliminary results of performance tests of the soft X-ray imaging microscope with a compact laser-produced plasma X-ray source

Monte Carlo simulation of the interaction of X-ray spectrum with human tissue, in the energies range of diagnostic radiology

International Nuclear Information System (INIS)

Cayllahua Q, L. F.; Apaza V, G.; Vega R, J. L.

2015-10-01

Full text: This paper is an approach to an increasingly complete knowledge about the nature of the processes that occur during a simple examination of radiological diagnosis; know as X-rays are produced and how they will put their energy into the tissue of patients when they are subjected to an examination of radiological diagnosis. First, using the MCNP code an X-rays tube was simulated, where electrons are emitted from a filament (cathode) which travel a certain distance with a certain kinetic energy and then be stopped suddenly in the tungsten target. The X-rays emitted as a result of this interaction, are previously filtered through the inherent filter of Pyrex glass and then by a thin aluminum foil before quantification as an X-rays spectrum. 6 spectra (for 60, 80, 100, 120 and 140 KeV) were obtained. Second, using the Penelope code was simulated the interaction of the X-rays spectrum, obtained in the first part with human tissue, putting as simile of human tissue water phantoms of different thicknesses. As final result: dose of energy deposited (in 2 and 3-dimensional) and reflected, absorbed and transmitted photons spectra. (Author)

Equipment for x- and gamma ray radiography

International Nuclear Information System (INIS)

Abd Nasir Ibrahim; Azali Muhammad; Ab Razak Hamzah; Abd Aziz Mohamed; Mohammad Pauzi Ismail

2004-01-01

The following topics related to the equipment for x - and gamma ray radiography are discussed in this chapter. The topics are x-ray source for Industrial Radiography: properties of x-ray, generation of x-ray, mechanism of x-ray production, x-ray equipment, power supply, distribution of x-ray intensity along the tube: gamma ray source for Industrial Radiography: properties of gamma rays, gamma ray sources, gamma ray projectors on cameras, source changing. Care of Radiographic Equipments: Merits and Demerits of x and Gamma Rays

Si(Li) X-ray detector

International Nuclear Information System (INIS)

Yuan Xianglin; Li Zhiyong; Hong Xiuse

1990-08-01

The fabrication technology of the 10∼80 mm 2 Si(Li) X-ray detectors are described and some problems concerning technology and measurement are discussed. The specifications of the detectors are shown as well. The Si(Li) X-ray detector is a kind of low energy X-ray detectors. Owing to very high energy resolution, fine linearity and high detection efficiency in the range of low energy X-rays, it is widely used in the fields of nuclear physics, medicine, geology and environmental protection, etc,. It is also a kernel component for the scanning electron microscope and X-ray fluorescence analysis systems

Guides for intraoral x-rays

International Nuclear Information System (INIS)

Ogunsunlade, O.A.

1988-01-01

An h-shaped exterior guide for use in combination with a SNAP-A-RAY film holder for accurately aligning a beam from an X-ray cone with an X-ray film during the process of taking intraoral periapical dental X-rays of the maxillary and mandibular teeth is described comprising: a first guide arm laterally and detachably connectable through a housing means; a traverse arm extending from the midpoint of the first guide arm and parallel to the X-ray film; and a second guide arm extending perpendicularly from an end of the traverse arm toward a plane of the X-ray film and in parallel relation up to an end point of the first guide arm

PAL-XFEL soft X-ray scientific instruments and X-ray optics: First commissioning results

Science.gov (United States)

Park, Sang Han; Kim, Minseok; Min, Changi-Ki; Eom, Intae; Nam, Inhyuk; Lee, Heung-Soo; Kang, Heung-Sik; Kim, Hyeong-Do; Jang, Ho Young; Kim, Seonghan; Hwang, Sun-min; Park, Gi-Soo; Park, Jaehun; Koo, Tae-Yeong; Kwon, Soonnam

2018-05-01

We report an overview of soft X-ray scientific instruments and X-ray optics at the free electron laser (FEL) of the Pohang Accelerator Laboratory, with selected first-commissioning results. The FEL exhibited a pulse energy of 200 μJ/pulse, a pulse width of power of 10 500 was achieved. The estimated total time resolution between optical laser and X-ray pulses was <270 fs. A resonant inelastic X-ray scattering spectrometer was set up; its commissioning results are also reported.

X-ray survey of the Pleiades: dependence of X-ray luminosity on stellar age

International Nuclear Information System (INIS)

Micela, G.; Sciortino, S.; Serio, S.; Vaiana, G.S.; Golub, L.; Harnden, F.R.; Rosner, R.

1984-01-01

The study of X-ray emission of stellar clusters, allows to decouple the influence of some individual stellar parameters, as initial conditions, composition and age, on the stellar X-ray function. The authors report preliminary results from an Einstein X-ray survey of the Pleiades. (Auth.)

X-ray detector

International Nuclear Information System (INIS)

Whetten, N.R.; Houston, J.M.

1977-01-01

An ionization chamber for use in determining the spatial distribution of x-ray photons in tomography systems comprises a plurality of substantially parallel, planar anodes separated by parallel, planar cathodes and enclosed in a gas of high atomic weight at a pressure from approximately 10 atmospheres to approximately 50 atmospheres. The cathode and anode structures comprise metals which are substantially opaque to x-ray radiation and thereby tend to reduce the resolution limiting effects of x-ray fluoresence in the gas. In another embodiment of the invention the anodes comprise parallel conductive bars disposed between two planar cathodes. Guard rings eliminate surface leakage currents between adjacent electrodes. 8 figures

Characterization of gold nanoparticle binding to microtubule filaments

International Nuclear Information System (INIS)

Zhou, Jing C.; Wang Xianghuai; Xue Mei; Xu Zheng; Hamasaki, Toshikazu; Yang, Yang; Wang Kang; Dunn, Bruce

2010-01-01

Microtubule (MT) protein filaments were used as templates for fabricating Au nanowires as a bottom-up approach for fabricating building blocks for future integrated circuits. Photochemical reduction methods were employed to form Au nanoparticles which bind and uniformly cover the MT filaments. Synthesis of the MT-templated Au nanowires was characterized using UV/vis spectroscopy and transmission electron microscopy (TEM). In addition, binding between the MT filaments and Au nanoparticles was investigated using surface enhanced Raman spectroscopy (SERS) and X-ray photoelectron spectroscopy (XPS) to establish the nature of the binding sites. A variety of functional groups were identified by SERS to interact with the Au including imidazole, sulfur, aromatic rings, amine, and carboxylate. The imidazole ring in the histidine is the most prominent functional group for Au binding. The results from these studies provide better understanding of the binding between Au and the biotemplate and give insight concerning methods to improve Au coverage for MT-templated Au nanowires.

X-Ray-induced Deuterium Enrichment of N-rich Organics in Protoplanetary Disks: An Experimental Investigation Using Synchrotron Light

Energy Technology Data Exchange (ETDEWEB)

Gavilan, Lisseth; Carrasco, Nathalie [LATMOS, Université Versailles St Quentin, UPMC Université Paris 06, CNRS, 11 blvd d’Alembert, F-78280 Guyancourt (France); Remusat, Laurent; Roskosz, Mathieu [IMPMC, CNRS UMR 7590, Sorbonne Universités, UPMC Université Paris 06, IRD, Muséum National d’Histoire Naturelle, CP 52, 57 rue Cuvier, Paris F-75231 (France); Popescu, Horia; Jaouen, Nicolas [SEXTANTS beamline, SOLEIL synchrotron, L’Orme des Merisiers, F-91190 Saint-Aubin (France); Sandt, Christophe [SMIS beamline, SOLEIL synchrotron, L’Orme des Merisiers, F-91190 Saint-Aubin (France); Jäger, Cornelia [Laboratory Astrophysics and Cluster Physics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University and Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena (Germany); Henning, Thomas [Max-Planck Institute for Astronomy Königstuhl 17, D-69117 Heidelberg (Germany); Simionovici, Alexandre [Institut des Sciences de la Terre, Observatoire des Sciences de l’Univers de Grenoble, BP 53, F-38041 Grenoble (France); Lemaire, Jean Louis [Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ. Paris Sud, Université Paris-Saclay, F-91405 Orsay (France); Mangin, Denis, E-mail: lisseth.gavilan@latmos.ipsl.fr [Institut Jean Lamour, CNRS, Université de Lorraine, F-54011 Nancy (France)

2017-05-01

The deuterium enrichment of organics in the interstellar medium, protoplanetary disks, and meteorites has been proposed to be the result of ionizing radiation. The goal of this study is to simulate and quantify the effects of soft X-rays (0.1–2 keV), an important component of stellar radiation fields illuminating protoplanetary disks, on the refractory organics present in the disks. We prepared tholins, nitrogen-rich organic analogs to solids found in several astrophysical environments, e.g., Titan’s atmosphere, cometary surfaces, and protoplanetary disks, via plasma deposition. Controlled irradiation experiments with soft X-rays at 0.5 and 1.3 keV were performed at the SEXTANTS beamline of the SOLEIL synchrotron, and were immediately followed by ex-situ infrared, Raman, and isotopic diagnostics. Infrared spectroscopy revealed the preferential loss of singly bonded groups (N–H, C–H, and R–N≡C) and the formation of sp{sup 3} carbon defects with signatures at ∼1250–1300 cm{sup −1}. Raman analysis revealed that, while the length of polyaromatic units is only slightly modified, the introduction of defects leads to structural amorphization. Finally, tholins were measured via secondary ion mass spectrometry to quantify the D, H, and C elemental abundances in the irradiated versus non-irradiated areas. Isotopic analysis revealed that significant D-enrichment is induced by X-ray irradiation. Our results are compared to previous experimental studies involving the thermal degradation and electron irradiation of organics. The penetration depth of soft X-rays in μ m-sized tholins leads to volume rather than surface modifications: lower-energy X-rays (0.5 keV) induce a larger D-enrichment than 1.3 keV X-rays, reaching a plateau for doses larger than 5 × 10{sup 27} eV cm{sup −3}. Synchrotron fluences fall within the expected soft X-ray fluences in protoplanetary disks, and thus provide evidence of a new non-thermal pathway to deuterium fractionation of

X-Ray-induced Deuterium Enrichment of N-rich Organics in Protoplanetary Disks: An Experimental Investigation Using Synchrotron Light

Science.gov (United States)

Gavilan, Lisseth; Remusat, Laurent; Roskosz, Mathieu; Popescu, Horia; Jaouen, Nicolas; Sandt, Christophe; Jäger, Cornelia; Henning, Thomas; Simionovici, Alexandre; Lemaire, Jean Louis; Mangin, Denis; Carrasco, Nathalie

2017-05-01

The deuterium enrichment of organics in the interstellar medium, protoplanetary disks, and meteorites has been proposed to be the result of ionizing radiation. The goal of this study is to simulate and quantify the effects of soft X-rays (0.1-2 keV), an important component of stellar radiation fields illuminating protoplanetary disks, on the refractory organics present in the disks. We prepared tholins, nitrogen-rich organic analogs to solids found in several astrophysical environments, e.g., Titan’s atmosphere, cometary surfaces, and protoplanetary disks, via plasma deposition. Controlled irradiation experiments with soft X-rays at 0.5 and 1.3 keV were performed at the SEXTANTS beamline of the SOLEIL synchrotron, and were immediately followed by ex-situ infrared, Raman, and isotopic diagnostics. Infrared spectroscopy revealed the preferential loss of singly bonded groups (N-H, C-H, and R-N≡C) and the formation of sp3 carbon defects with signatures at ˜1250-1300 cm-1. Raman analysis revealed that, while the length of polyaromatic units is only slightly modified, the introduction of defects leads to structural amorphization. Finally, tholins were measured via secondary ion mass spectrometry to quantify the D, H, and C elemental abundances in the irradiated versus non-irradiated areas. Isotopic analysis revealed that significant D-enrichment is induced by X-ray irradiation. Our results are compared to previous experimental studies involving the thermal degradation and electron irradiation of organics. The penetration depth of soft X-rays in μm-sized tholins leads to volume rather than surface modifications: lower-energy X-rays (0.5 keV) induce a larger D-enrichment than 1.3 keV X-rays, reaching a plateau for doses larger than 5 × 1027 eV cm-3. Synchrotron fluences fall within the expected soft X-ray fluences in protoplanetary disks, and thus provide evidence of a new non-thermal pathway to deuterium fractionation of organic matter.

Stabilized x-ray generator power supply

International Nuclear Information System (INIS)

Saha, Subimal; Purushotham, K.V.; Bose, S.K.

1986-01-01

X-ray diffraction and X-ray fluorescence analysis are very much adopted in laboratories to determine the type and structure of the constituent compounds in solid materials, chemical composition of materials, stress developed on metals etc. These experiments need X-ray beam of fixed intensity and wave length. This can only be achieved by X-ray generator having highly stabilized tube voltage and tube current. This paper describes how X-ray tube high voltage and electron beam current are stabilized. This paper also highlights generation of X-rays, diffractometry and X-ray fluorescence analysis and their wide applications. Principle of operation for stabilizing the X-ray tube voltage and current, different protection circuits adopted, special features of the mains H.V. transformer and H.T. tank are described in this report. (author)