WorldWideScience

Sample records for burst x-ray light

  1. Gamma-ray burst optical light-curve zoo: comparison with X-ray observations

    CERN Document Server

    Zaninoni, Elena; Margutti, Raffaella; Oates, Samantha; Chincarini, Guido

    2013-01-01

    We present a comprehensive analysis of the optical and X-ray light curves (LCs) and spectral energy distributions (SEDs) of a large sample of gamma-ray burst (GRB) afterglows to investigate the relationship between the optical and X-ray emission after the prompt phase. We collected the optical data from the literature and determined the shapes of the optical LCs. Then, using previously presented X-ray data we modeled the optical/X-ray SEDs. We studied the SED parameter distributions and compared the optical and X-ray LC slopes and shapes. The optical and X-ray spectra become softer as a function of time while the gas-to-dust ratios of GRBs are higher than the values calculated for the Milky Way and the Large and Magellanic Clouds. For 20% of the GRBs the difference between the optical and X-ray slopes is consistent with 0 or 1=4 within the uncertainties (we did it not consider the steep decay phase), while in the remaining 80% the optical and X-ray afterglows show significantly different temporal behaviors. I...

  2. Light Echos in Kerr Geometry: A Source of High Frequency QPOs from Random X-ray Bursts

    Science.gov (United States)

    Fukumura, K.; Kazanas, D.

    2008-01-01

    We propose that high frequency quasi-periodic oscillations (HFQPOs) can be produced from randomly-formed X-ray bursts (flashes) by plasma interior to the ergosphere of a rapidly-rotating black hole. We show by direct computation of their orbits that the photons comprising the observed X-ray light curves, if due to a multitude of such flashes, are affected significantly by the black hole's dragging of inertial frames; the photons of each such burst arrive to an observer at infinity in multiple (double or triple), distinct 'bunches' separated by a roughly constant time lag of t/M approximately equal to 14, regardless of the bursts' azimuthal position. We argue that every other such 'bunch' represents photons that follow trajectories with an additional orbit around the black hole at the photon circular orbit radius (a photon 'echo'). The presence of this constant lag in the response function of the system leads to a QPO feature in its power density spectra, even though the corresponding light curve consists of a totally stochastic signal. This effect is by and large due to the black hole spin and is shown to gradually diminish as the spin parameter a decreases or the radial position of the burst moves outside the static limit surface (ergosphere). Our calculations indicate that for a black hole with Kerr parameter of a/M=0.99 and mass of M=10*Msun the QPO is expected at a frequency of approximately 1.3-1.4 kHz. We discuss the plausibility and observational implications of our model/results as well as its limitations.

  3. X-ray bursts observed with JEM-X

    DEFF Research Database (Denmark)

    Brandt, Søren Kristian; Chenevez, Jérôme; Lund, Niels; Budtz-Jørgensen, Carl; Westergaard, Niels Jørgen Stenfeldt

    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....

  4. 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....

  5. THE HARD X-RAY BEHAVIOR OF AQL X-1 DURING TYPE-I BURSTS

    International Nuclear Information System (INIS)

    We report the discovery of an anti-correlation between the soft and hard X-ray light curves of the X-ray binary Aql X-1 when bursting. This behavior may indicate that the corona is cooled by the soft X-ray shower fed by the type-I X-ray bursts, and that this process happens within a few seconds. Stacking the Aql X-1 light curves of type-I bursts, we find a shortage in the 40-50 keV band, delayed by 4.5 ± 1.4 s with respect to the soft X-rays. The photospheric radius expansion bursts are different in that neither a shortage nor an excess shows up in the hard X-ray light curve

  6. A Correlation Between the Intrinsic Brightness and Average Decay Rate of Gamma-ray Burst X-ray Afterglow Light Curves

    CERN Document Server

    Racusin, J L; de Pasquale, M; Kocevski, D

    2016-01-01

    We present a correlation between the average temporal decay ({\\alpha}X,avg,>200s) and early-time luminosity (LX,200s) of X-ray afterglows of gamma-ray bursts as observed by Swift-XRT. Both quantities are measured relative to a rest frame time of 200 s after the {\\gamma}-ray trigger. The luminosity average decay correlation does not depend on specific temporal behavior and contains one scale independent quantity minimizing the role of selection effects. This is a complementary correlation to that discovered by Oates et al. (2012) in the optical light curves observed by Swift-UVOT. The correlation indicates that on average, more luminous X-ray afterglows decay faster than less luminous ones, indicating some relative mechanism for energy dissipation. The X-ray and optical correlations are entirely consistent once corrections are applied and contamination is removed. We explore the possible biases introduced by different light curve morphologies and observational selection effects, and how either geometrical effe...

  7. The Fermi-GBM X-ray burst monitor

    Science.gov (United States)

    Linares, M.; Fermi GBM X-ray Burst Collaboration

    2010-12-01

    We discuss the first results of the Fermi-GBM all-sky search for X-ray bursts. The very large field of view and X-ray response of the Fermi-GBM make it a unique instrument to study rare, bright and short-lived X-ray bursts. We are performing a systematic search that exploits such capabilities. We present results on long/intermediate type I X-ray bursts, an unusual kind of thermonuclear bursts from accreting neutron stars, and show how Fermi-GBM is giving for the first time robust measurements of their recurrence time.

  8. Long X-ray burst monitoring with INTEGRAL

    DEFF Research Database (Denmark)

    X-ray bursts are thermonuclear explosions on the surface of accreting neutron stars in low mass X-ray binary systems. In the frame of the INTEGRAL observational Key Programme over the Galactic Center a good number of the known X-ray bursters are frequently being monitored. An international....... Of special interest are low luminosity bursting sources that exhibit X-ray bursts of very different durations allowing to study the transition from a hydrogen-rich bursting regime to a pure helium regime and from helium burning to carbon burning. I will present results obtained from INTEGRAL archive...

  9. Delayed X-Ray Afterglows from Obscured Gamma-Ray Bursts in Star-Forming Regions

    OpenAIRE

    Meszaros, P.; Gruzinov, A.

    2000-01-01

    For Gamma-Ray Bursts occurring in dense star-forming regions, the X-ray afterglow behavior minutes to days after the trigger may be dominated by the small-angle scattering of the prompt X-ray emission off dust grains. We give a simple illustrative model for the X-ray light curves at different X-ray energies, and discuss possible implications. A bump followed by a steeper decay in soft X-rays is predicted for bursts which are heavily obscured in the optical.

  10. Linking burst-only X-ray binary sources to faint X-ray transients

    OpenAIRE

    Campana, S.

    2009-01-01

    Burst-only sources are X-ray sources showing up only during short bursts but with no persistent emission (at least with the monitoring instrument which led to their discovery). These bursts have spectral characteristics consistent with thermonuclear (type I) burst from the neutron star surface, linking burst-only sources to neutron star X-ray binary transients. We have carried out a series of snapshot observations of the entire sample of burst-only sources with the Swift satellite. We found a...

  11. INTEGRAL monitoring of unusually long X-ray bursts

    DEFF Research Database (Denmark)

    Thermonuclear bursts on the surface of accreting neutron stars in low mass X-ray binaries have been studied for many years and have in a few cases confirmed theoretical models of nuclear ignition and burning mechanisms. The large majority of X-ray bursts last less than 100s. A good number of the...... known X-ray bursters are frequently observed by INTEGRAL, in particular in the frame of the Key Programmes. Taking advantage of the INTEGRAL instrumentation, an international collaboration led by the JEM-X team at the Danish National Space Institute has been monitoring the occurrence of uncommon burst...... events lasting more than a few minutes. Of special interest are exceptional X-ray bursts which duration about a few tens of minutes is intermediate between usual short bursts and hour long superbursts. The processes driving such long bursts are not yet fully understood: depending on the composition of...

  12. X-Ray Observations of Gamma-Ray Burst Afterglows

    OpenAIRE

    Frontera, Filippo

    2004-01-01

    The discovery by the BeppoSAX satellite of X-ray afterglow emission from the gamma-ray burst which occurred on 28 February 1997 produced a revolution in our knowledge of the gamma-ray burst phenomenon. Along with the discovery of X-ray afterglows, the optical afterglows of gamma-ray bursts were discovered and the distance issue was settled, at least for long $\\gamma$-ray bursts. The 30 year mystery of the gamma-ray burst phenomenon is now on the way to solution. Here I rewiew the observationa...

  13. INTEGRAL monitoring of unusually long X-ray bursts

    DEFF Research Database (Denmark)

    Chenevez, Jérôme; Falanga, M.; Kuulkers, E.;

    2008-01-01

    exceptional burst events lasting more than ~10 minutes. Half of the dozen so-called intermediate long bursts registered so far have been observed by INTEGRAL. The goal is to derive a comprehensive picture of the relationship between the nuclear ignition processes and the accretion states of the system leading......X-ray bursts are thermonuclear explosions on the surface of accreting neutron stars in X-ray binaries. As most of the known X-ray bursters are frequently observed by INTEGRAL, an international collaboration have been taking advantage of its instrumentation to specifically monitor the occurrence of...

  14. X-ray spectra of bursting neutron stars

    International Nuclear Information System (INIS)

    The global properties of type-I x-ray bursts can be successfully accounted for by the thermonuclear shell flash model of accreting neutron stars. According to this model, the luminosity of a relatively large burst approaches to the Eddington luminosity. We calculate the atmospheric structure and the photon energy spectrum of x-ray bursting neutron star taking account of comptonization. From the x-ray spectrum, theoretical color temperature-luminosity diagram is obtained. Observational color temperature-luminosity diagram of x-ray burster is constructed using data of Japanese x-ray sutellite Tenma. Comparing our theoretical diagram with observational ones, we can estimate a mass-radius relation of neutron stars and distances to the galactic center. (Mori, K.)

  15. The INTEGRAL view of intermediate long X-ray bursts

    DEFF Research Database (Denmark)

    CONCLUSIONS Most intermediate bursts are observed from low luminosity sources and are interpreted as long pure He bursts. If no H is accreted, they are consistent with the burning of a slowly accreted, thick He layer, in Ultra Compact X-ray Binaries (UCXB) where the donor star is probably a...

  16. Supercollapsars and their X-ray Bursts

    CERN Document Server

    Komissarov, S S

    2009-01-01

    The very first stars in the Universe can be very massive, frequently reaching $10^3M_\\odot$. If born in large numbers such massive stars can have strong impact on the subsequent star formation producing strong ionising radiation and contaminating the primordial gas with heavy elements. They would leave behind massive black holes that could act as seeds for growing supermassive black holes of active galactic nuclei. Given the anticipated fast rotation such stars would end their live as supermassive collapsars and drive powerful magnetically-dominated jets. In this letter we investigate the possibility of observing the bursts of high-energy emission similar to the Long Gamma Ray Bursts associated with normal collapsars. We show that during the collapse of supercollapsars, the Blandford-Znajek mechanism can extract up to $10^{56}$erg at a rate of few$\\times10^{52}$erg/s. Due to the higher intrinsic time scale and higher redshift the observed burst duration increases by a factor of $\\simeq 1000$ and can reach one...

  17. A Strong X-Ray Burst from the Low Mass X-Ray Binary EXO0748-676

    OpenAIRE

    Wolff, Michael T.; Becker, Peter A.; Ray, Paul S.; Wood, Kent S.

    2005-01-01

    We have observed an unusually strong X-ray burst as a part of our regular eclipse timing observations of the low mass binary system EXO0748-676. The burst peak flux was 5.2x10^-8 ergs cm^-2 s^-1, approximately five times the normal peak X-ray burst flux observed from this source by RXTE. Spectral fits to the data strongly suggest that photospheric radius expansion occurred during the burst. In this Letter we examine the properties of this X-ray burst, which is the first example of a radius ex...

  18. Neutron Stars and Thermonuclear X-ray Bursts

    Science.gov (United States)

    Bhattacharyya, Sudip

    2007-01-01

    Studies of thermonuclear X-ray bursts can be very useful to constrain the spin rate, mass and radius of a neutron star approaching EOS model of high density cold matter in the neutron star cores. +k Extensive observation and analysis of the data from the rising portions of the bursts - modeling of burst oscillations and thermonuclear flame spreading. +k Theoretical study of thermonuclear flame spreading on the rapidly spinning neutron stars should be done considering all the main physical effects (including magnetic field, nuclear energy generation, Coriolis effect, strong gravity, etc.).

  19. Understanding Neutron Stars using Thermonuclear X-ray Bursts

    Science.gov (United States)

    Bhattacharyya, S.

    2007-01-01

    Studies of thermonuclear X-ray bursts can be very useful to constrain the spin rate, mass and radius of a neutron star = EOS model of high density cold matter in the neutron star cores. Extensive observation and analysis of the data from the rising portions of the bursts = modeling of burst oscillations and thermonuclear flame spreading. Theoretical study of thermonuclear flame spreading on the rapidly spinning neutron stars should be done considering all the main physical effects (including magnetic field, nuclear energy generation, Coriolis effect, strong gravity, etc.).

  20. Maxi observations of long X-ray bursts

    CERN Document Server

    Serino, Motoko; Tamagawa, Toru; Sakamoto, Takanori; Nakahira, Satoshi; Matsuoka, Masaru; Yamaoka, Kazutaka; Negoro, Hitoshi

    2016-01-01

    We report nine long X-ray bursts from neutron stars, detected with Monitor of All-sky X-ray Image (MAXI). Some of these bursts lasted for hours, and hence are qualified as superbursts, which are prolonged thermonuclear flashes on neutron stars and are relatively rare events. MAXI observes roughly 85% of the whole sky every 92 minutes in the 2-20 keV energy band, and has detected nine bursts with a long e-folding decay time, ranging from 0.27 to 5.2 hours, since its launch in 2009 August until 2015 August. The majority of the nine events were found to originate from transient X-ray sources. The persistent luminosities of the sources, when these prolonged bursts were observed, were lower than 1% of the Eddington luminosity for five of them and lower than 20% for the rest. This trend is contrastive to the 18 superbursts observed before MAXI, all but two of which originated from bright persistent sources. The distribution of the total emitted energy, i.e., the product of e-folding time and luminosity, of these bu...

  1. Millisecond Oscillations During Thermonuclear X-ray Bursts

    CERN Document Server

    Muno, M P

    2004-01-01

    I review the basic phenomenology and theory of the millisecond brightness oscillations observed during thermonuclear X-ray bursts from 13 of approximately 70 accreting neutron stars in low-mass X-ray binaries. Compelling observations indicate that the oscillations are produced by surface brightness patterns on the rapidly rotating neutron stars. However, it remains to be understood (1) why the brightness patterns producing them persist for up to 15 s during an X-ray burst, whereas the burning should cover the entire surface in less than 1 s, and (2) why the frequencies drift upward by about 5 Hz during the course of the burst. These peculiarities can probably be explained by taking into account the expansion of the surface layers caused by the burning, zonal flows that form due to pressure gradients between the equator and poles, and Rossby-Alfven modes that are excited in the surface ocean. Further progress toward understanding how burning progresses on the surface of the neutron star can be made with a next...

  2. Detection of burning ashes from thermonuclear X-ray bursts

    CERN Document Server

    Kajava, J J E; Poutanen, J; Cumming, A; Suleimanov, V; Kuulkers, E

    2016-01-01

    When neutron stars (NS) accrete gas from low-mass binary companions, explosive nuclear burning reactions in the NS envelope fuse hydrogen and helium into heavier elements. The resulting thermonuclear (type-I) X-ray bursts produce energy spectra that are fit well with black bodies, but a significant number of burst observations show deviations from Planck spectra. Here we present our analysis of RXTE/PCA observations of X-ray bursts from the NS low-mass X-ray binary HETE J1900.1-2455. We have discovered that the non-Planckian spectra are caused by photo-ionization edges. The anti-correlation between the strength of the edges and the colour temperature suggests that the edges are produced by the nuclear burning ashes that have been transported upwards by convection and become exposed at the photosphere. The atmosphere model fits show that occasionally the photosphere can consist entirely of metals, and that the peculiar changes in black body temperature and radius can be attributed to the emergence and disappea...

  3. X-ray Burst Oscillations: From Flame Spreading to the Cooling Wake

    CERN Document Server

    Mahmoodifar, Simin

    2015-01-01

    Type I X-ray bursts are thermonuclear flashes observed from the surface of accreting neutron stars in Low Mass X-ray Binaries. Oscillations have been observed during the rise and/or decay of some of these X-ray bursts. Those seen during the rise can be well explained by a spreading hot spot model, but to date there haven't been any quantitative studies that consistently track the oscillation amplitude both during the rise and decay (tail) of bursts. Here we compute the light curves and amplitudes of oscillations in X-ray burst models that realistically account for both flame spreading and subsequent cooling. We present results for two such "cooling wake" models, a "canonical" cooling model where each patch on the neutron star surface heats and cools identically, and an "asymmetric" model where parts of the star cool at different rates. We show that while canonical cooling models can generate oscillations in the tails of bursts, they cannot easily produce the highest observed modulation amplitudes. Alternative...

  4. The X-ray Telescope for the SWIFT Gamma-Ray Burst Mission

    International Nuclear Information System (INIS)

    The X-ray Telescope (XRT) for the SWIFT mission, built by the international consortium from Pennsylvania State University (United States), University of Leicester (UK) and Osservatorio Astronomico di Brera (Italy), is already installed on the SWIFT spacecraft. The XRT has two key functions on SWIFT; to determine locations of GRBs to better than 5 arc seconds within 100 seconds of initial detection of a burst and to measure spectra and light curves of the X-ray afterglow over around four orders of magnitude of decay in the afterglow intensity. This paper summarises the XRT performance, operating modes and sensitivity for the detection of prompt and extended X-ray afterglows from gamma-ray bursts. The performance characteristics have been determined from data taken during the ground calibration campaign at MPE's Panter facility in September 2002

  5. The Rapid Burster and its X-ray bursts: extremes of accretion and thermonuclear burning

    OpenAIRE

    Klis, van der, M.; Zand, in 't, J.J.M.; Watts, A.; Bagnoli, T.

    2015-01-01

    X-ray bursts originate from accreting neutron stars (NSs) in X-ray binaries (XRBs). They come in two flavours: thermonuclear bursts are due to the sudden runaway burning of the material accreted on the surface; accretion bursts signal a sudden change in the mass accretion rate, leading to enhanced emission in the innermost regions of the accretion flow. While thermonuclear bursts have been observed from 105 NSs as of writing, accretion bursts remain enigmatically confined to only two sources....

  6. The Search for Type 1 X-ray Bursts with Fermi/GBM

    Science.gov (United States)

    Jenke, Peter; Linares, M.; Connaughton, V.; Camero-Arranz, A.; Finger, M. H.; WIlson-Hodge, C. A.; Van Der Horst, A.; Fermi GBM X-ray Burst Collaboration

    2012-01-01

    We discuss the first results of the Fermi-GBM all-sky search for X-ray bursts. The very large field of view and X-ray response of the Fermi-GBM make it a unique instrument to study rare, bright and short-lived X-ray bursts. We are performing a systematic search that exploits such capabilities. We present results on long/intermediate type I X-ray bursts, an unusual kind of thermonuclear bursts from accreting neutron stars, and show how Fermi-GBM is giving, for the first time, robust measurements of their recurrence time.

  7. Dependence of X-Ray Burst Models on Nuclear Reaction Rates

    OpenAIRE

    Cyburt, R. H.; Amthor, A. M.; Heger, A.; Johnson, E.; Keek, L.; Meisel, Z.; Schatz, H.; Smith, K

    2016-01-01

    X-ray bursts are thermonuclear flashes on the surface of accreting neutron stars and reliable burst models are needed to interpret observations in terms of properties of the neutron star and the binary system. We investigate the dependence of X-ray burst models on uncertainties in (p,$\\gamma$), ($\\alpha$,$\\gamma$), and ($\\alpha$,p) nuclear reaction rates using fully self-consistent burst models that account for the feedbacks between changes in nuclear energy generation and changes in astrophy...

  8. Two-phase X-ray burst from GX 3+1 observed by INTEGRAL

    NARCIS (Netherlands)

    Chenevez, J.; Falanga, M.; Brandt, S.; Farinelli, R.; Frontera, F.; Goldwurm, A.; in 't Zand, J.J.M.; Kuulkers, E.; Lund, N.

    2006-01-01

    INTEGRAL detected on August 31, 2004, an unusual thermonuclear X-ray burst from the low-mass X-ray binary GX 3+1. Its duration was 30 min, which is between the normal burst durations for this source (

  9. Thermonuclear X-ray bursts from IGR J17473-2721

    DEFF Research Database (Denmark)

    The X-ray transient source IGR J17473-2721 exhibited a renewed episode of activity between March and September 2008, which was shortly preceded by a thermonuclear X-ray burst. Interpretation of the source bursting behaviour will be presented from observation results obtained by four satellites....

  10. Modeling Gamma-Ray Burst X-Ray Flares Within the Internal Shock Model

    Science.gov (United States)

    Maxham, Amanda; Zhang, Bing

    2009-12-01

    X-ray afterglow light curves have been collected for over 400 Swift gamma-ray bursts (GRBs) with nearly half of them having X-ray flares superimposed on the regular afterglow decay. Evidence suggests that gamma-ray prompt emission and X-ray flares share a common origin and that at least some flares can only be explained by long-lasting central engine activity. We have developed a shell model code to address the question of how X-ray flares are produced within the framework of the internal shock model. The shell model creates randomized GRB explosions from a central engine with multiple shells and follows those shells as they collide, merge, and spread, producing prompt emission and X-ray flares. We pay special attention to the time history of central engine activity, internal shocks, and observed flares, but do not calculate the shock dynamics and radiation processes in detail. Using the empirical Ep -E iso (Amati) relation with an assumed Band function spectrum for each collision and an empirical flare temporal profile, we calculate the gamma-ray (Swift/BAT band) and X-ray (Swift/XRT band) lightcurves for arbitrary central engine activity and compare the model results with the observational data. We show that the observed X-ray flare phenomenology can be explained within the internal shock model. The number, width, and occurring time of flares are then used to diagnose the central engine activity, putting constraints on the energy, ejection time, width, and number of ejected shells. We find that the observed X-ray flare time history generally reflects the time history of the central engine, which reactivates multiple times after the prompt emission phase with progressively reduced energy. The same shell model predicts an external shock X-ray afterglow component, which has a shallow decay phase due to the initial pile-up of shells onto the blast wave. However, the predicted X-ray afterglow is too bright as compared with the observed flux level, unless epsilon e is

  11. MODELING GAMMA-RAY BURST X-RAY FLARES WITHIN THE INTERNAL SHOCK MODEL

    International Nuclear Information System (INIS)

    X-ray afterglow light curves have been collected for over 400 Swift gamma-ray bursts (GRBs) with nearly half of them having X-ray flares superimposed on the regular afterglow decay. Evidence suggests that gamma-ray prompt emission and X-ray flares share a common origin and that at least some flares can only be explained by long-lasting central engine activity. We have developed a shell model code to address the question of how X-ray flares are produced within the framework of the internal shock model. The shell model creates randomized GRB explosions from a central engine with multiple shells and follows those shells as they collide, merge, and spread, producing prompt emission and X-ray flares. We pay special attention to the time history of central engine activity, internal shocks, and observed flares, but do not calculate the shock dynamics and radiation processes in detail. Using the empirical Ep -Eiso (Amati) relation with an assumed Band function spectrum for each collision and an empirical flare temporal profile, we calculate the gamma-ray (Swift/BAT band) and X-ray (Swift/XRT band) lightcurves for arbitrary central engine activity and compare the model results with the observational data. We show that the observed X-ray flare phenomenology can be explained within the internal shock model. The number, width, and occurring time of flares are then used to diagnose the central engine activity, putting constraints on the energy, ejection time, width, and number of ejected shells. We find that the observed X-ray flare time history generally reflects the time history of the central engine, which reactivates multiple times after the prompt emission phase with progressively reduced energy. The same shell model predicts an external shock X-ray afterglow component, which has a shallow decay phase due to the initial pile-up of shells onto the blast wave. However, the predicted X-ray afterglow is too bright as compared with the observed flux level, unless εe is as low

  12. 30S RI Beam Production and X-ray Bursts

    CERN Document Server

    Kahl, David; Binh, Dam Nguyen; Chen, Jun; Hashimoto, Takashi; Hayakawa, Seiya; Kim, Aram; Kubono, Shigeru; Kurihara, Yuzo; Lee, Nam Hee; Michimasa, Shin'ichiro; Nishimura, Shunji; Van Ouellet, Christian; nia, Kiana Setoodeh; Wakabayashi, Yasuo; Yamaguchi, Hideotoshi

    2009-01-01

    The present work reports the results of 30S radioactive beam development for a future experiment directly measuring data to extrapolate the 30S(alpha,p) stellar reaction rate in Type I X-ray bursts, a phenomena where nuclear explosions occur repeatedly on the surface of accreting neutron stars. We produce the radioactive ion 30S via the 3He(28Si,30S)n reaction, by bombarding a cryogenically cooled target of 3He at 400 Torr and 80 K with 28Si beams of 6.9 and 7.54 MeV/u. In order to perform a successful future experiment which allows us to calculate the stellar 30S(alpha, p) reaction rate, Hauser-Feshbach calculations indicate we require a 30S beam of ~10^5 particles per second at ~32 MeV. Based on our recent beam development experiments in 2006 and 2008, it is believed that such a beam may be fabricated in 2009 according to the results presented. We plan to measure the 4He(30S,p) cross-section at astrophysical energies in 2009, and some brief remarks on the planned (alpha,p) technique are also elucidated.

  13. The hard X-ray shortages prompted by the clock bursts in GS 1826-238

    International Nuclear Information System (INIS)

    We report on a study of GS 1826-238 using all available Rossi X-Ray Timing Explorer observations, concentrating on the behavior of the hard X-rays during type-I bursts. We find a hard X-ray shortage at 30-50 keV prompted by the shower of soft X-rays coming from type-I bursts. This shortage happens with a time delay after the peak of the soft flux of 3.6 ± 1.2 s. The behavior of hard X-rays during bursts indicates cooling and reheating of the corona, during which a large amount of energy is required. We speculate that this energy originates from the feedback of the type-I bursts to the accretion process, resulting in a rapid temporary increase of the accretion rate.

  14. The observers' view of (very) long X-ray bursts: they are super!

    OpenAIRE

    Kuulkers, Erik

    2003-01-01

    In many X-ray point sources on the sky, the X-ray emission arises because hydrogen and/or helium is accreted onto a neutron star from a nearby donor star. When this matter settles on the neutron star surface, it will undergo nuclear fusion. For a large range of physical parameters the fusion is unstable. The resulting thermo-nuclear explosions last from seconds to minutes. They are observed as short flares in X-rays and are called `type I X-ray bursts'. Recently, hours-long X-ray flares have ...

  15. Puzzling thermonuclear burst behaviour from the transient low-mass X-ray binary IGR J17473-2721

    DEFF Research Database (Denmark)

    Chenevez, Jérôme; Altamirano, Diego; Galloway, Duncan;

    2010-01-01

    We investigate the thermonuclear bursting behaviour of IGR J17473−2721, an X-ray transient that in 2008 underwent a 6-month long outburst, starting (unusually) with an X-ray burst. We detected a total of 57 thermonuclear bursts throughout the outburst with AGILE, Swift, Rossi X-ray Timing Explore...

  16. The Microchannel X-ray Telescope for the Gamma-Ray Burst mission SVOM

    CERN Document Server

    Gotz, D; Cordier, B; Paul, J; Evans, P; Beardmore, A; Martindale, A; Willingale, R; O'Brien, P; Basa, S; Rossin, C; Godet, O; Webb, N; Greiner, J; Nandra, K; Meidinger, N; Perinati, E; Santangelo, A; Mercier, K; Gonzalez, F

    2014-01-01

    We present the Microchannel X-ray Telescope, a new light and compact focussing telescope that will be flying on the Sino-French SVOM mission dedicated to Gamma-Ray Burst science. The MXT design is based on the coupling of square pore micro-channel plates with a low noise pnCCD. MXT will provide an effective area of about 50 cmsq, and its point spread function is expected to be better than 3.7 arc min (FWHM) on axis. The estimated sensitivity is adequate to detect all the afterglows of the SVOM GRBs, and to localize them to better then 60 arc sec after five minutes of observation.

  17. Long Type I X-ray Bursts and Neutron Star Interior Physics

    OpenAIRE

    Cumming, Andrew; Macbeth, Jared; Zand, J. J. M. in't; Page, Dany

    2005-01-01

    Superbursts are very energetic Type I X-ray bursts discovered in recent years by long term monitoring of X-ray bursters, believed to be due to unstable ignition of carbon in the deep ocean of the neutron star. A number of "intermediate duration" bursts have also been observed, probably associated with ignition of a thick helium layer. We investigate the sensitivity of these long X-ray bursts to the thermal profile of the neutron star crust and core. We first compare cooling models of superbur...

  18. Modification of gravitational redshift of x-ray burst produced by pulsar surface magnetoplasma

    Institute of Scientific and Technical Information of China (English)

    Zhu Jun; Ji Pei-Yong

    2008-01-01

    In this paper,the propagation of x-ray bursts in the magnetoplasma of pulsar magnetosphere is discussed.The electromagnetic interaction between x-ray bursts and magnetoplasma is described as some geometry.The electromagnetic effects of surface superstrong magnetic field and dynamic effects of outflowing magnetoplasma of pulsars are treated as an optical metric.The Gordon metric is introduced to represent the gravitational metric and optical metric.So the propagation of x-ray bursts in magnetoplasma of pulsars can be described as x-ray bursts transmitting in an effective space characterized by Gordon metric.The modification of gravitational redshift,attributed to the flowing magnetoplasma of pulsars,is obtained and it is shown that the modification is of redshift and can reach the same magnitude as the gravitational redshift for ordinary pulsars.

  19. The discovery of rapidly repetitive X-ray bursts from a new source in Scorpius

    Science.gov (United States)

    Lewin, W. H. G.; Doty, J.; Clark, G. W.; Bradt, H. V. D.; Doxsey, R.; Hearn, D. R.; Hoffman, J. A.; Jernigan, J. G.; Li, F. K.; Rappaport, S. A.

    1976-01-01

    Rapidly repetitive X-ray bursts have been observed from a new X-ray source in Scorpius. More than 2000 bursts were observed during the 4-day continual SAS-3 observations of this source designated MXB 1730-335. The time interval between bursts varied from a minimum of about 6 s to a maximum of about 5 minutes. The energy in a given burst is approximately linearly proportional to the time interval to the next burst. The largest bursts observed last for about 60 s and represent an energy release of approximately 10 to the 40th ergs for an assumed distance to the source of 10 kpc. The smallest bursts observed last only for a few seconds. We suggest that the bursts are caused by sporadic precipitations of plasma from a reservoir in the magnetosphere of a neutron star. The reservoir is replenished at a nearly constant rate by mass transferred from a binary companion.

  20. THE FERMI-GBM X-RAY BURST MONITOR: THERMONUCLEAR BURSTS FROM 4U 0614+09

    Energy Technology Data Exchange (ETDEWEB)

    Linares, M.; Chakrabarty, D. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States); Connaughton, V.; Bhat, P. N.; Briggs, M. S.; Preece, R. [CSPAR and Physics Department, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Jenke, P.; Kouveliotou, C.; Wilson-Hodge, C. A. [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Van der Horst, A. J. [Astronomical Institute ' Anton Pannekoek' , University of Amsterdam, NL-1090-GE Amsterdam (Netherlands); Camero-Arranz, A.; Finger, M.; Paciesas, W. S. [Universities Space Research Association, Huntsville, AL 35805 (United States); Beklen, E. [Physics Department, Suleyman Demirel University, 32260 Isparta (Turkey); Von Kienlin, A. [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Postfach 1312, D-85748 Garching (Germany)

    2012-12-01

    Thermonuclear bursts from slowly accreting neutron stars (NSs) have proven difficult to detect, yet they are potential probes of the thermal properties of the NS interior. During the first year of a systematic all-sky search for X-ray bursts using the Gamma-ray Burst Monitor aboard the Fermi Gamma-ray Space Telescope we have detected 15 thermonuclear bursts from the NS low-mass X-ray binary 4U 0614+09 when it was accreting at nearly 1% of the Eddington limit. We measured an average burst recurrence time of 12 {+-} 3 days (68% confidence interval) between 2010 March and 2011 March, classified all bursts as normal duration bursts and placed a lower limit on the recurrence time of long/intermediate bursts of 62 days (95% confidence level). We discuss how observations of thermonuclear bursts in the hard X-ray band compare to pointed soft X-ray observations and quantify such bandpass effects on measurements of burst radiated energy and duration. We put our results for 4U 0614+09 in the context of other bursters and briefly discuss the constraints on ignition models. Interestingly, we find that the burst energies in 4U 0614+09 are on average between those of normal duration bursts and those measured in long/intermediate bursts. Such a continuous distribution in burst energy provides a new observational link between normal and long/intermediate bursts. We suggest that the apparent bimodal distribution that defined normal and long/intermediate duration bursts during the last decade could be due to an observational bias toward detecting only the longest and most energetic bursts from slowly accreting NSs.

  1. The Fermi-GBM X-Ray Burst Monitor: Thermonuclear Bursts from 4U 0614+09

    Science.gov (United States)

    Linares, M.; Connaughton, V.; Jenke, P.; van der Horst, A. J.; Camero-Arranz, A.; Kouveliotou, C.; Chakrabarty, D.; Beklen, E.; Bhat, P. N.; Briggs, M. S.; Finger, M.; Paciesas, W. S.; Preece, R.; von Kienlin, A.; Wilson-Hodge, C. A.

    2012-12-01

    Thermonuclear bursts from slowly accreting neutron stars (NSs) have proven difficult to detect, yet they are potential probes of the thermal properties of the NS interior. During the first year of a systematic all-sky search for X-ray bursts using the Gamma-ray Burst Monitor aboard the Fermi Gamma-ray Space Telescope we have detected 15 thermonuclear bursts from the NS low-mass X-ray binary 4U 0614+09 when it was accreting at nearly 1% of the Eddington limit. We measured an average burst recurrence time of 12 ± 3 days (68% confidence interval) between 2010 March and 2011 March, classified all bursts as normal duration bursts and placed a lower limit on the recurrence time of long/intermediate bursts of 62 days (95% confidence level). We discuss how observations of thermonuclear bursts in the hard X-ray band compare to pointed soft X-ray observations and quantify such bandpass effects on measurements of burst radiated energy and duration. We put our results for 4U 0614+09 in the context of other bursters and briefly discuss the constraints on ignition models. Interestingly, we find that the burst energies in 4U 0614+09 are on average between those of normal duration bursts and those measured in long/intermediate bursts. Such a continuous distribution in burst energy provides a new observational link between normal and long/intermediate bursts. We suggest that the apparent bimodal distribution that defined normal and long/intermediate duration bursts during the last decade could be due to an observational bias toward detecting only the longest and most energetic bursts from slowly accreting NSs.

  2. The Fermi–GBM Three-year X-Ray Burst Catalog

    Science.gov (United States)

    Jenke, P. A.; Linares, M.; Connaughton, V.; Beklen, E.; Camero-Arranz, A.; Finger, M. H.; Wilson-Hodge, C. A.

    2016-08-01

    The Fermi Gamma-ray Burst Monitor (GBM) is an all-sky gamma-ray monitor well known in the gamma-ray burst (GRB) community. Although GBM excels in detecting the hard, bright extragalactic GRBs, its sensitivity above 8 keV and its all-sky view make it an excellent instrument for the detection of rare, short-lived Galactic transients. In 2010 March, we initiated a systematic search for transients using GBM data. We conclude this phase of the search by presenting a three-year catalog of 1084 X-ray bursts. Using spectral analysis, location, and spatial distributions we classified the 1084 events into 752 thermonuclear X-ray bursts, 267 transient events from accretion flares and X-ray pulses, and 65 untriggered gamma-ray bursts. All thermonuclear bursts have peak blackbody temperatures broadly consistent with photospheric radius expansion (PRE) bursts. We find an average rate of 1.4 PRE bursts per day, integrated over all Galactic bursters within about 10 kpc. These include 33 and 10 bursts from the ultra-compact X-ray binaries 4U 0614+09 and 2S 0918-549, respectively. We discuss these recurrence times and estimate the total mass ejected by PRE bursts in our Galaxy.

  3. Recent advances in the modelling of classical novae and type I X-ray bursts

    International Nuclear Information System (INIS)

    Classical nova outbursts and type I X-ray bursts are thermonuclear stellar explosions driven by charged-particle reactions. Extensive numerical simulations of nova explosions have shown that the accreted envelopes attain peak temperatures between 0.1 and 0.4 GK, for about several hundred seconds, and therefore, their ejecta is expected to show signatures of significant nuclear activity. Indeed, it has been claimed that novae play some role in the enrichment of the interstellar medium through a number of intermediate-mass elements. This includes 17O, 15N, and 13C, systematically overproduced in huge amounts with respect to solar abundances, with a lower contribution to a number of species with A7Li, 19F, or 26Al. In this review, we present new 1-D hydrodynamic models of classical nova outbursts, from the onset of accretion up to the explosion and ejection phases. Special emphasis is put on their gross observational properties (including constraints from meteoritic presolar grains and potential gamma-ray signatures) and on their associated nucleosynthesis. Multidimensional models of mixing at the core-envelope interface during outbursts will also be presented. The impact of nuclear uncertainties on the final yields will be also outlined. Detailed analysis of the relevant reactions along the main nuclear path for type I X-ray bursts has only been scarcely addressed, mainly in the context of parameterized one-zone models. Here, we present a detailed study of the nucleosynthesis and nuclear processes powering type I X-ray bursts. The reported bursts have been computed by means of a spherically symmetric (1D), Lagrangian, hydrodynamic code, linked to a nuclear reaction network that contains 325 isotopes (from 1H to 107Te), and 1392 nuclear processes. These evolutionary sequences, followed from the onset of accretion up to the explosion and expansion stages, have been performed for two different metallicities to explore the dependence between the extension of the main

  4. The Fermi-GBM X-ray burst monitor: thermonuclear bursts from 4U 0614+09

    CERN Document Server

    Linares, M; Jenke, P; van der Horst, A J; Camero-Arranz, A; Kouveliotou, C; Chakrabarty, D; Beklen, E; Bhat, P N; Briggs, M S; Finger, M; Paciesas, W; Preece, R; von Kienlin, A; Wilson-Hodge, C A

    2012-01-01

    Thermonuclear bursts from slowly accreting neutron stars (NSs) have proven difficult to detect, yet they are potential probes of the thermal properties of the neutron star interior. During the first year of a systematic all-sky search for X-ray bursts using the Gamma-ray Burst Monitor (GBM) aboard the Fermi Gamma-ray Space Telescope we have detected 15 thermonuclear bursts from the NS low-mass X-ray binary 4U 0614+09, when it was accreting at nearly 1% of the Eddington limit. We measured an average burst recurrence time of 12+/-3 d (68% confidence interval) between March 2010 and March 2011, classified all bursts as normal duration bursts and placed a lower limit on the recurrence time of long/intermediate bursts of 62 d (95% confidence level). We discuss how observations of thermonuclear bursts in the hard X-ray band compare to pointed soft X-ray observations, and quantify such bandpass effects on measurements of burst radiated energy and duration. We put our results for 4U 0614+09 in the context of other bu...

  5. X-ray suppression in gamma-ray bursts through resonant Compton scattering

    Science.gov (United States)

    Brainerd, J. J.

    1992-01-01

    An X-ray that scatters with an electron in the first Landau level of a strong magnetic field is converted into a gamma ray. This process has a resonant cross section at X-ray energies and is therefore highly likely to occur even when the first Landau level is sparsely populated. Converted X-rays are cyclotron absorbed, maintaining the equilibrium between the cyclotron photon density and the population of the first Landau level. By suppressing a neutron star's black body emission, this mechanism can produce a gamma-ray burst with a low X-ray flux.

  6. Self-organized criticality in X-ray flares of gamma-ray burst afterglows

    OpenAIRE

    Wang, F.Y.; Dai, Z. G.

    2013-01-01

    X-ray flares detected in nearly half of gamma-ray burst (GRB) afterglows are one of the most intriguing phenomena in high-energy astrophysics. All the observations indicate that the central engines of bursts, after the gamma-ray emission has ended, still have long periods of activity, during which energetic explosions eject relativistic materials, leading to late-time X-ray emission. It is thus expected that X-ray flares provide important clues to the nature of the central engines of GRBs, an...

  7. A fundamental plane for gamma-ray bursts with X-ray plateaus

    CERN Document Server

    Dainotti, Maria Giovanna; Hernandez, Xavier; Ostrowski, Michał

    2016-01-01

    A class of long Gamma-Ray Bursts (GRBs) presenting light curves with an extended plateau phase in their X-ray afterglows obeys a correlation between the rest frame end time of the plateau, $T_a$, and its corresponding X-ray luminosity, $L_{a}$, Dainotti et al. (2008). In this work we perform an analysis of a total sample of 176 {\\it Swift} GRBs with known redshifts, exhibiting afterglow plateaus. By adding a third parameter, that is the peak luminosity in the prompt emission, $L_{peak}$, we discover the existence of a new three parameter correlation, a GRB `fundamental plane'. The scatter of data about this plane becomes smaller when a class-specific GRB sample is defined. This sample of 122 GRBs is selected from the total sample by excluding GRBs with associated Supernovae (SNe), X-ray flashes and short GRBs with extended emission. Moreover, we further limit our analysis to GRBs with lightcurves having good data coverage and almost flat plateaus, 40 GRBs forming our `gold sample'. The intrinsic scatter, $\\si...

  8. The X-ray Bursts from the Magnetar Candidate 1E 2259+586

    CERN Document Server

    Gavriil, F P; Woods, P M; Gavriil, Fotis P.; Kaspi, Victoria M.; Woods, Peter M.

    2004-01-01

    We present a statistical analysis of the X-ray bursts observed from the 2002 June 18 outburst of the Anomalous X-ray Pulsar (AXP) 1E 2259+586, observed with the Proportional Counter Array aboard the Rossi X-ray Timing Explorer. We show that the properties of these bursts are similar to those of Soft Gamma-Repeaters (SGRs). The similarities we find are: the burst durations follow a log-normal distribution which peaks at 99 ms, the differential burst fluence distribution is well described by a power law of index -1.7, the burst fluences are positively correlated with the burst durations, the distribution of waiting times is well described by a log-normal distribution of mean 47 s, and the bursts are generally asymmetric with faster rise than fall times. However, we find several quantitative differences between the AXP and SGR bursts. Specifically, there is a correlation of burst phase with pulsed intensity, the AXP bursts we observed exhibit a wider range of durations, the correlation between burst fluence and ...

  9. X-Ray Reflection of Thermonuclear Bursts from Neutron Stars: Constraining Flames with RXTE and an Outlook on NICER

    Science.gov (United States)

    Keek, Laurens

    2016-04-01

    Thermonuclear X-ray bursts observed from accreting neutron stars are employed to study, e.g., the nuclear physics of rare isotopes and the dense matter equation of state. Recent observations indicate that bursts strongly affect their accretion environment, and reprocessed burst emission may reflect off the inner accretion disk. The spectra of the short (10-100s) bursts are, however, of insufficient quality to accurately separate the neutron star signal from accretion disk emission and burst reflection. Only for two rare "superbursts" with durations of several hours did RXTE/PCA spectra show burst reflection signatures. We discuss the case of 4U 1636-536, where the reflection signal traced the evolution of the ionization state of the inner disk. Our simulations show that a large reflection fraction may indicate that the disk puffs up due to burst irradiation. After separating the direct burst emission from reflection, we show that the rise of the superburst light curve is shaped by a stalling carbon flame. In the near future, the Neutron Star Interior Composition ExploreR (NICER) will have a band-pass that extends below 2 keV, where reflection dominates the burst spectrum, and which was not probed by RXTE. Therefore, NICER will be able to detect reflection features during the frequent short bursts. NICER will open a new field of studying the interaction of bursts and the accretion environment, which will inform us of which bursts are optimally suited for neutron star mass-radius measurements.

  10. What can NuSTAR do for X-ray bursts?

    DEFF Research Database (Denmark)

    Chenevez, Jérôme; Tomsick, John; Chakrabarty, Deepto;

    2012-01-01

    Unstable thermonuclear burning on the surface of accreting neutron stars is commonly observed as type I X-ray bursts. The flux released during some strong bursts can temporarily exceed the Eddington limit, driving the neutron star photosphere to such large radii that heavy-element ashes of nuclear...

  11. What can NuSTAR do for X-ray bursts?

    DEFF Research Database (Denmark)

    Chenevez, Jérôme; Tomsick, J.; Chakrabarty, D.;

    Unstable thermonuclear burning on the surface of accreting neutron stars is commonly observed as type I X-ray bursts. The flux released during some strong bursts can temporarily exceed the Eddington limit, driving the neutron star photosphere to such large radii that heavy-element ashes of nuclear...

  12. The first radius-expansion X-ray burst from GX 3+1

    OpenAIRE

    Kuulkers, E; Klis, van der, M.

    2000-01-01

    During several observations in 1999 August with RXTE of the low-mass X-ray binary GX 3+1, we found a single short and strong X-ray burst. This is the first burst from GX 3+1 which clearly shows evidence for radius expansion of the neutron-star photosphere during the thermo-nuclear runaway. We show that the cooling phase of the neutron star photosphere starts already just before the end of the contraction phase. Considering the fact that the radius expansion is due to the burst luminosity bein...

  13. The WATCH solar X-ray burst catalogue

    DEFF Research Database (Denmark)

    Crosby, N.; Lund, Niels; Vilmer, N.; Sunyaev, R.

    1998-01-01

    The WATCH experiment aboard the GRANAT satellite provides observations of the Sun in the deka-keV range covering the years 1990 through mid-1992. An introduction to the experiment is given followed by an explanation of how the WATCH solar burst catalogue was created. The different parameters listed...... for each burst is given and are furthermore explained....

  14. Long duration X-ray burst from GX 3+1

    DEFF Research Database (Denmark)

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

    2004-01-01

    During an observation of the Galactic Center the JEM-X instrument on INTEGRAL detected an unusally long X-ray burst from GX 3+1. The burst began on August 31 at 18:57 UTC After an precursor spike lasting 7 s where the burst reached a flux of about 2000 mCrab in the 4 to 20 keV band the flux fell to...

  15. Puzzling thermonuclear burst behaviour from the transient low-mass X-ray binary IGR J17473-2721

    DEFF Research Database (Denmark)

    Chenevez, Jérôme

    2010-01-01

    We investigate the thermonuclear bursting behaviour of IGR J17473-2721, an X-ray transient that in 2008 underwent a six month long outburst, starting (unusually) with an X-ray burst. We detected a total of 57 thermonuclear bursts throughout the outburst with AGILE, Swift, RXTE, and INTEGRAL. The ...

  16. Inelastic x-ray scattering at the National Synchrotron Light

    International Nuclear Information System (INIS)

    The research program at the inelastic x-ray scattering beamline at the National Synchrotron Light Source is focused on the study of elementary excitations in condensed matter with total energy resolution on the order of 0.1 eV to 1.0 eV. Results from selected experiments are reported to demonstrate the capability of the beamline as well as the information can be obtained from inelastic x- ray scattering experiments

  17. Lag-luminosity relation in gamma-ray burst X-ray flares

    CERN Document Server

    Margutti, R

    2010-01-01

    In strict analogy to prompt pulses, X-ray flares observed by Swift-XRT in long Gamma-Ray Bursts define a lag-luminosity relation: L_p,iso \\propto t_lag^{-0.95+/-0.23}. The lag-luminosity is proven to be a fundamental law extending 5 decades in time and 5 in energy. This is direct evidence that GRB X-ray flares and prompt gamma-ray pulses are produced by the same mechanism.

  18. Exposing the Nuclear Burning Ashes of Radius Expansion Type I X-ray Bursts

    CERN Document Server

    Weinberg, N N; Schatz, H; Weinberg, Nevin N.; Bildsten, Lars; Schatz, Hendrik

    2006-01-01

    We solve for the evolution of the vertical extent of the convective region of a neutron star atmosphere during a Type I X-ray burst. The convective region is well-mixed with ashes of nuclear burning and its extent determines the rise time of the burst light curve. Using a full nuclear reaction network, we show that the maximum vertical extent of the convective region during photospheric radius expansion (RE) bursts can be sufficiently great that: (1) some ashes of burning are ejected by the radiation driven wind during the RE phase and, (2) some ashes of burning are exposed at the neutron star surface following the RE phase. We find that ashes with mass number A ~ 30 - 60 are mixed in with the ejected material. We calculate the expected column density of ejected and surface ashes in hydrogen-like states and determine the equivalent widths of the resulting photoionization edges from both the wind and neutron star surface. We find that these can exceed 100 eV and are potentially detectable. A detection would pr...

  19. Iron lines in the X-ray afterglows of Gamma-ray bursts

    Science.gov (United States)

    Piro, L.

    1998-12-01

    X-ray measurements of iron lines can provide a powerful diagnostics of the environment of Gamma-ray bursts, thus enlightening the still misterious nature of the central engine powering these phenomena. Furthermore, they would allow a direct measurement of the distance of the GRB, bypassing completely the long chain of steps that, from the Gamma and X-ray localization, brings to the optical determination of the redshift. In this contribution we will present the results of a search of this feature in the BeppoSAX X-ray afterglows of GRB. We will discuss their implication for near future missions, as AXAF and XMM.

  20. An Extended Burst Tail from SGR 1900+14 with a Thermal X-ray Spectrum

    Science.gov (United States)

    Lenters, Geoffrey T.; Woods, Peter M.; Goupell, Johnathan E.; Kouveliotou, Chryssa; Goegues, Ersin; Hurley, Kevin; Frederiks, Dmitry; Golenetskii, Sergey; Swank, Jean; Six, N. Frank (Technical Monitor)

    2002-01-01

    The Soft Gamma Repeater, SGR 1900+14, entered a new phase of activity in April 2001 initiated by the intermediate flare recorded on April 18. Ten days following this flare, we discovered an abrupt increase in the source flux between consecutive RXTE orbits. This X-ray flux excess decayed over the next several minutes and was subsequently linked to a high fluence burst from SGR 1900+14 recorded by other spacecraft (Ulysses and KONUS) while the SGR was Earth-occulted for RXTE. We present here spectral and temporal analysis of both the burst of 28 April and the long X-ray tail following it. We draw comparisons with other bursts and flares from SGR 1900+14 which have shown extended X-ray excesses (e.g. 1998 August 29) and discuss their physical origin.

  1. Beacons in the sky. Classical novae vs. X-ray bursts

    International Nuclear Information System (INIS)

    Thermonuclear runaways are at the origin of some of the most energetic and frequent stellar cataclysmic events. In this review talk, we outline our understanding of the mechanisms leading to classical nova explosions and X-ray bursts, together with their associated nucleosynthesis. In particular, we focus on the interplay between nova outbursts and the Galactic chemical abundances (mainly 13C, 15N, and 17O), the synthesis of radioactive nuclei of interest for gamma-ray astronomy (7Be-7Li, 22Na, or 26Al), the endpoint of nova nucleosynthesis, based both on theoretical and observational grounds, and the recent discovery of presolar meteoritic grains, both in the Murchison and Acfer 094 meteorites, likely condensed in nova shells. Recent progress in the modeling of X-ray bursts as well as an insight into the nuclear uncertainties affecting critical reactions, for both novae and X-ray bursts, will also be presented. (author)

  2. Stellar Pyrotechnics: Nucleosynthesis in Classical Novae and X-Ray Bursts

    International Nuclear Information System (INIS)

    Thermonuclear runaways are at the origin of some of the most energetic and frequent stellar cataclysmic events. In this paper, we review our understanding of the mechanisms leading to classical nova explosions and x-ray bursts, together with their associated nu- cleosynthesis. In particular, we focus on the interplay between nova outbursts and the Galactic chemical abundances (mainly 13C, 15N, and 17O), the synthesis of radioactive nuclei of interest for gamma-ray astronomy (7Be-7Li, 22Na, or 26Al), the endpoint of nova nucleosynthesis, based both on theoretical and observational grounds, and the recent discovery of presolar meteoritic grains, both in the Murchison and Acfer 094 meteorites, likely condensed in nova shells. Recent progress in the modeling of x-ray bursts as well as an insight into the nuclear uncertainties affecting critical reactions, for both novae and x-ray bursts, are also reviewed

  3. Exposing the Nuclear Burning Ashes of Radius Expansion Type I X-Ray Bursts

    Science.gov (United States)

    Weinberg, Nevin N.; Bildsten, Lars; Schatz, Hendrik

    2006-03-01

    We solve for the evolution of the vertical extent of the convective region of a neutron star atmosphere during a type I X-ray burst. The convective region is well mixed with ashes of nuclear burning, and its extent determines the rise time of the burst light curve. Using a full nuclear reaction network, we show that the maximum vertical extent of the convective region during photospheric radius expansion (RE) bursts can be sufficiently great that (1) some ashes of burning are ejected by the radiation-driven wind during the RE phase and (2) some ashes of burning are exposed at the neutron star surface following the RE phase. We find that ashes with mass numbers in the range A~30-60 are mixed in with the ejected material. We calculate the expected column density of ejected and surface ashes in hydrogen-like states and determine the equivalent widths of the resulting photoionization edges from both the wind and the neutron star surface. We find that these can exceed 100 eV and are potentially detectable. A detection would probe the nuclear burning processes and might enable a measurement of the gravitational redshift of the neutron star. In addition, we find that in bursts with pure helium burning layers, protons from (α, p) reactions cause a rapid onset of the 12C(p, γ)13N(α, p)16O reaction sequence. The sequence bypasses the relatively slow 12C(α, γ)16O reaction and leads to a sudden surge in energy production that is directly observable as a rapid (~millisecond) increase in flux during burst rise.

  4. 10 Years of XRT light curves: a general view of the X-ray afterglow

    CERN Document Server

    Bardho, O; Gendre, B

    2015-01-01

    During the pre-Swift era, a clustering of light curves was observed in the X-ray, optical and infrared afterglow of gamma-ray bursts. We used a sample of 254 GRB X-ray afterglows to check this fact in the Swift era. We corrected fluxes for distance, time dilation and losses of energy due to cosmological effects. With all our data in hand, we faced with a problem: our data were scattered. We investigated 3 possibilities to explain this, namely: the clustering does not exist, there are problems during calibration of data, and there are instrumental problems. We finally confirm that our sample is consistent with Dainotti correlation.

  5. The WATCH solar X-ray burst catalogue

    DEFF Research Database (Denmark)

    Crosby, N.; Lund, Niels; Vilmer, N.;

    1998-01-01

    The WATCH experiment aboard the GRANAT satellite provides observations of the Sun in the deka-keV range covering the years 1990 through mid-1992. An introduction to the experiment is given followed by an explanation of how the WATCH solar burst catalogue was created. The different parameters listed...

  6. The Fermi-GBM 3-year X-ray Burst Catalog

    CERN Document Server

    Jenke, P A; Connaughton, V; Beklen, E; Camero-Arranz, A; Finger, M H; Wilson-Hodge, C A

    2016-01-01

    The Fermi Gamma Ray Burst Monitor (GBM) is an all sky gamma-ray monitor well known in the gamma-ray burst community. Although GBM excels in detecting the hard, bright extragalactic GRBs, its sensitivity above 8 keV and all-sky view make it an excellent instrument for the detection of rare, short-lived Galactic transients. In March 2010, we initiated a systematic search for transients using GBM data. We conclude this phase of the search by presenting a 3 year catalog of 1084 non-solar events. Using spectral analysis, location and spatial distributions we subdivided the 1084 events into 752 thermonuclear X-ray bursts, 267 transient events from accretion flares and X-ray pulses, and 65 untriggered gamma-ray bursts.

  7. Self-organized criticality in X-ray flares of gamma-ray burst afterglows

    CERN Document Server

    Wang, F Y

    2013-01-01

    X-ray flares detected in nearly half of gamma-ray burst (GRB) afterglows are one of the most intriguing phenomena in high-energy astrophysics. All the observations indicate that the central engines of bursts, after the gamma-ray emission has ended, still have long periods of activity, during which energetic explosions eject relativistic materials, leading to late-time X-ray emission. It is thus expected that X-ray flares provide important clues to the nature of the central engines of GRBs, and more importantly, unveil the physical mechanism of the flares themselves, which has so far remained mysterious. Here we report statistical results of X-ray flares of GRBs with known redshifts, and show that X-ray flares and solar flares share three statistical properties: power-law frequency distributions for energies, durations, and waiting times. All of the distributions can be well understood within the physical framework of a self-organized criticality (SOC) system. The statistical properties of X-ray flares of GRBs...

  8. Evidence for the Connection between Prompt and X-ray Afterglow emission of Swift-Detected Gamma-Ray Bursts

    CERN Document Server

    Grupe, Dirk; Verres, Peter; Zhang, Binbin; Gehrels, Neil

    2013-01-01

    When a massive star explodes as a Gamma Ray Burst information about this explosion is retained in the properties of the prompt and afterglow emission. We report on tight relationships between the prompt and X-ray afterglow emission of Swift-detected Gamma Ray Bursts found from BAT and XRT data between 2004 December and 2013 March. These relations suggest that the prompt and afterglow emission are closely linked. In particular, we find very strong correlations between the BAT 15-150keV T90 and the break times before and after the plateau phase in the X-ray 0.3-10keV afterglow light curves. We also find a strong anti-correlation between the photon index of the GRB prompt emission and the X-ray spectral slope of the afterglow. Further, anti-correlations exist between the rest frame peak energy in the prompt emission, E_ peak, and the X-ray afterglow decay slope during the plateau phase and the break times after the plateau phase. The rest-frame break times before and after the plateau phase are also anti-correla...

  9. Hydrogen-Triggered Type I X-ray Bursts in a Two-Zone Model

    OpenAIRE

    Cooper, Randall L.; Narayan, Ramesh

    2007-01-01

    We use the two-zone model of Cooper & Narayan to study the onset and time evolution of hydrogen-triggered type I X-ray bursts on accreting neutron stars. At the lowest accretion rates, thermally unstable hydrogen burning ignites helium as well and produces a mixed hydrogen and helium burst. For somewhat higher accretion rates, thermally unstable hydrogen burning does not ignite helium and thus triggers only a weak hydrogen flash. The peak luminosities of weak hydrogen flashes are typically mu...

  10. Flare classification with X-ray, particles, and radio bursts

    International Nuclear Information System (INIS)

    Some important works are concisely reviewed on flare classification with the observational results from various satellites during the last solar maximum. First, the observational definitions of impulsive and gradual types of flares are given. Next, the phenomena pertaining to meter-wave bursts are described and explained. When these meter-wave phenomena are taken into account, it is shown that clear classification can be achieved. Basically, all the flares are classified into two types of events, that is, impulsive and gradual flares. This simple classification may help to understand the relationships among the various phenomena on the sun and those in the interplanetary space. (author)

  11. Comprehensive Study of the X-Ray Flares from Gamma-ray Bursts Observed by Swift

    Science.gov (United States)

    Yi, Shuang-Xi; Xi, Shao-Qiang; Yu, Hai; Wang, F. Y.; Mu, Hui-Jun; Lü, Lian-Zhong; Liang, En-Wei

    2016-06-01

    X-ray flares are generally supposed to be produced by later activities of the central engine, and may share a similar physical origin with the prompt emission of gamma-ray bursts (GRBs). In this paper, we have analyzed all significant X-ray flares from the GRBs observed by Swift from 2005 April to 2015 March. The catalog contains 468 bright X-ray flares, including 200 flares with redshifts. We obtain the fitting results of X-ray flares, such as start time, peak time, duration, peak flux, fluence, peak luminosity, and mean luminosity. The peak luminosity decreases with peak time, following a power-law behavior {L}{{p}}\\propto {T}{peak,z}-1.27. The flare duration increases with peak time. The 0.3–10 keV isotropic energy of the distribution of X-ray flares is a log-normal peaked at {10}51.2 erg. We also study the frequency distributions of flare parameters, including energies, durations, peak fluxes, rise times, decay times, and waiting times. Power-law distributions of energies, durations, peak fluxes, and waiting times are found in GRB X-ray flares and solar flares. These distributions could be well explained by a fractal-diffusive, self-organized criticality model. Some theoretical models based on magnetic reconnection have been proposed to explain X-ray flares. Our result shows that the relativistic jets of GRBs may be dominated by Poynting flux.

  12. X-ray Optics for BES Light Source Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Dennis [Argonne National Lab. (ANL), Argonne, IL (United States); Padmore, Howard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lessner, Eliane [Dept. of Energy (DOE), Washington DC (United States). Office of Science

    2013-03-27

    potentially revolutionary science involves soft excitations such as magnons and phonons; in general, these are well below the resolution that can be probed by today’s optical systems. The study of these low-energy excitations will only move forward if advances are made in high-resolution gratings for the soft X-ray energy region, and higher-resolution crystal analyzers for the hard X-ray region. In almost all the forefront areas of X-ray science today, the main limitation is our ability to focus, monochromate, and manipulate X-rays at the level required for these advanced measurements. To address these issues, the U.S. Department of Energy (DOE) Office of Basic Energy Sciences (BES) sponsored a workshop, X-ray Optics for BES Light Source Facilities, which was held March 27–29, 2013, near Washington, D.C. The workshop addressed a wide range of technical and organizational issues. Eleven working groups were formed in advance of the meeting and sought over several months to define the most pressing problems and emerging opportunities and to propose the best routes forward for a focused R&D program to solve these problems. The workshop participants identified eight principal research directions (PRDs), as follows: Development of advanced grating lithography and manufacturing for high-energy resolution techniques such as soft X-ray inelastic scattering. Development of higher-precision mirrors for brightness preservation through the use of advanced metrology in manufacturing, improvements in manufacturing techniques, and in mechanical mounting and cooling. Development of higher-accuracy optical metrology that can be used in manufacturing, verification, and testing of optomechanical systems, as well as at wavelength metrology that can be used for quantification of individual optics and alignment and testing of beamlines. Development of an integrated optical modeling and design framework that is designed and maintained specifically for X-ray optics. Development of

  13. Accretion disk signatures in Type I X-ray Bursts: prospects for future missions

    CERN Document Server

    Keek, L; Ballantyne, D R

    2016-01-01

    Type I X-ray bursts and superbursts from accreting neutron stars illuminate the accretion disk and produce a reflection signal that evolves as the burst fades. Examining the evolution of reflection features in the spectra will give insight into the burst-disk interaction, a potentially powerful probe of accretion disk physics. At present, reflection has been observed during only two bursts of exceptional duration. We investigate the detectability of reflection signatures with four of the latest well-studied X-ray observatory concepts: Hitomi, NICER, Athena, and LOFT. Burst spectra are modeled for different values for the flux, temperature, and the disk ionization parameter, which are representative for most known bursts and sources. The effective area and through-put of a Hitomi-like telescope are insufficient for characterizing burst reflection features. NICER and Athena will detect reflection signatures in Type I bursts with peak fluxes $\\ge 10^{-7.5}$ erg cm$^{-2}$ s$^{-1}$, and also effectively constrain ...

  14. Compact X-ray Light Source Workshop Report

    Energy Technology Data Exchange (ETDEWEB)

    Thevuthasan, Suntharampillai; Evans, James E.; Terminello, Louis J.; Koppenaal, David W.; Manke, Kristin L.; Plata, Charity

    2012-12-01

    This report, produced jointly by EMSL and FCSD, is the result of a workshop held in September 2011 that examined the utility of a compact x-ray light source (CXLS) in addressing many scientific challenges critical to advancing energy science and technology.

  15. Anisotropy of X-ray bursts from neutron stars with concave accretion disks

    CERN Document Server

    He, Chong-Chong

    2015-01-01

    Emission from neutron stars and accretion disks in low-mass X-ray binaries is not isotropic. The non-spherical shape of the disk as well as blocking of the neutron star by the disk and vice versa cause the observed flux to depend on the inclination angle of the disk with respect to the line of sight. This is of special importance for the interpretation of Type I X-ray bursts, which are powered by the thermonuclear burning of matter accreted onto the neutron star. Because part of the X-ray burst is reflected off the disk, the observed burst flux depends on the anisotropies for both direct emission from the neutron star and reflection off the disk. This influences measurements of source distance, mass accretion rate, and constraints on the neutron star equation of state. Previous studies made predictions of the anisotropy factor for the total burst flux, assuming a geometrically flat disk. Recently, detailed observations of two exceptionally long bursts (so-called superbursts) allowed for the first time for the...

  16. Data Selection Criteria for Spectroscopic Measurements of Neutron Star Radii with X-ray Bursts

    CERN Document Server

    Ozel, Feryal; Guver, Tolga

    2015-01-01

    Data selection and the determination of systematic uncertainties in the spectroscopic measurements of neutron star radii from thermonuclear X-ray bursts have been the subject of numerous recent studies. In one approach, the uncertainties and outliers were determined by a data-driven Bayesian mixture model, whereas in a second approach, data selection was performed by requiring that the observations follow theoretical expectations. We show here that, due to inherent limitations in the data, the theoretically expected trends are not discernible in the majority of X-ray bursts even if they are present. Therefore, the proposed theoretical selection criteria are not practical with the current data for distinguishing clean data sets from outliers. Furthermore, when the data limitations are not taken into account, the theoretically motivated approach selects a small subset of bursts with properties that are in fact inconsistent with the underlying assumptions of the method. We conclude that the data-driven selection...

  17. High-Resolution X-Ray Spectroscopy of the Bursting Pulsar GRO J1744-28

    CERN Document Server

    Degenaar, N; Harrison, F A; Kennea, J A; Kouveliotou, C; Younes, G

    2014-01-01

    The bursting pulsar GRO J1744-28 is a Galactic low-mass X-ray binary that distinguishes itself by displaying type-II X-ray bursts: brief, bright flashes of X-ray emission that likely arise from spasmodic accretion. Combined with its coherent 2.1 Hz X-ray pulsations and relatively high estimated magnetic field, it is a particularly interesting source to study the physics of accretion flows around neutron stars. Here we report on Chandra/HETG observations obtained near the peak of its bright 2014 accretion outburst. Spectral analysis suggests the presence of a broad iron emission line centered at E_l ~ 6.7 keV. Fits with a disk reflection model yield an inclination angle of i ~ 52 degrees and an inner disk radius of R_in ~ 85 GM/c^2, which is much further out than typically found for neutron star low-mass X-ray binaries. Assuming that the disk is truncated at the magnetospheric radius of the neutron star, we estimate a magnetic field strength of B ~ (2-6)E10 G. Furthermore, we identify an absorption feature nea...

  18. Spatial distribution of X-ray bursts in triggered lightning experiments

    Science.gov (United States)

    Bakhtiari, M.; Saleh, Z.; Dwyer, J.; Rassoul, H.; Uman, M.; Howard, J.

    2007-12-01

    During rocket-triggered lightning experiments, it has been observed that the dart leader phase is accompanied by bursts of X-rays. These experiments were carried out at the University of Florida/Florida Tech International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, FL. We report here the analysis of a sequence of X-ray bursts that occurred during the dart leader of a lightning flash triggered on July 31, 2007. The measurement of the penetrating X-ray photons was done with the Thunderstorm Energetic Radiation Array (TERA), which consists of more than 40 NaI detectors systematically distributed at various distances within 500 m from the launching tower. The integrated observed X-ray intensity at ground level over a short time prior to the return stroke shows a strong radial decay. On the other hand, the integrated radial X-ray distribution is rather flat at earlier times. The measurements are compared with simulations that include the physics of photon propagation through air. The results are consistent with a source that travels from high altitude to near ground level (the top of the rocket launching tower).

  19. Superorbital Periodic Modulation in Wind-Accretion High-Mass X-Ray Binaries from Swift Burst Alert Telescope Observations

    Science.gov (United States)

    Corbet, Robin H. D.; Krimm, Hans A.

    2013-01-01

    We report the discovery using data from the Swift-Burst Alert Telescope (BAT) of superorbital modulation in the wind-accretion supergiant high-mass X-ray binaries 4U 1909+07 (= X 1908+075), IGR J16418-4532, and IGR J16479-4514. Together with already known superorbital periodicities in 2S 0114+650 and IGR J16493-4348, the systems exhibit a monotonic relationship between superorbital and orbital periods. These systems include both supergiant fast X-ray transients and classical supergiant systems, and have a range of inclination angles. This suggests an underlying physical mechanism which is connected to the orbital period. In addition to these sources with clear detections of superorbital periods, IGR J16393-4643 (= AX J16390.4-4642) is identified as a system that may have superorbital modulation due to the coincidence of low-amplitude peaks in power spectra derived from BAT, Rossi X-Ray Timing Explorer Proportional Counter Array, and International Gamma-Ray Astrophysics Laboratory light curves. 1E 1145.1-6141 may also be worthy of further attention due to the amount of low-frequency modulation of its light curve. However, we find that the presence of superorbital modulation is not a universal feature of wind-accretion supergiant X-ray binaries.

  20. X-ray Spectral Diagnostics of $\\gamma$-Ray Burst Environments

    CERN Document Server

    Paerels, F B S; Heise, J; Liedahl, D A; Paerels, Frits; Kuulkers, Erik; Heise, John; Liedahl, Duane A.

    2000-01-01

    Recently, the detection of discrete features in the X-ray afterglow spectra of GRB970508 and GRB970828 was reported. The most natural interpretation of these features is that they are redshifted Fe K emission complexes. The identification of the line emission mechanism has drastic implications for the inferred mass of radiating material, end hence the nature of the burst site. X-ray spectroscopy provides a direct observational constraint on these properties of gamma-ray bursters. We briefly discuss how these constraints arise, in the context of an application to the spectrum of GRB970508.

  1. Millihertz Oscillation Frequency Drift Predicts the Occurrence of Type I X-ray Bursts

    CERN Document Server

    Altamirano, D; Wijnandsm, R; Cumming, A

    2007-01-01

    Millihertz quasi-periodic oscillations reported in three neutron-star low mass X-ray binaries have been suggested to be a mode of marginally stable nuclear burning on the neutron star surface. In this Letter, we show that close to the transition between the island and the banana state, 4U~1636--53 shows mHz QPOs whose frequency systematically decreases with time until the oscillations disappear and a Type I X-ray burst occurs. There is a strong correlation between the QPO frequency $\

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

    International Nuclear Information System (INIS)

    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

  3. A search for thermal X-ray signatures in Gamma-Ray Bursts I: Swift bursts with optical supernovae

    CERN Document Server

    Starling, R L C; Pe'er, A; Beardmore, A P; Osborne, J P

    2012-01-01

    The X-ray spectra of Gamma-Ray Bursts can generally be described by an absorbed power law. The landmark discovery of thermal X-ray emission in addition to the power law in the unusual GRB 060218, followed by a similar discovery in GRB 100316D, showed that during the first thousand seconds after trigger the soft X-ray spectra can be complex. Both the origin and prevalence of such spectral components still evades understanding, particularly after the discovery of thermal X-ray emission in the classical GRB 090618. Possibly most importantly, these three objects are all associated with optical supernovae, begging the question of whether the thermal X-ray components could be a result of the GRB-SN connection, possibly in the shock breakout. We therefore performed a search for blackbody components in the early Swift X-ray spectra of 11 GRBs that have or may have associated optical supernovae, accurately recovering the thermal components reported in the literature for GRBs 060218, 090618 and 100316D. We present the ...

  4. Nearly Coherent Oscillations in Type I X-Ray Bursts from KS 1731-260

    CERN Document Server

    Muno, M P; Morgan, E H; Bildsten, L; Muno, Michael P.; Fox, Derek W.; Morgan, Edward H.; Bildsten, Lars

    2000-01-01

    We present an analysis of the nine type I X-ray bursts that were observed from KS 1731-260 with RXTE. We find that the bursts divide naturally into two populations: ``fast bursts'' occur on the Banana Branch when the accretion rate is high and exhibit short decay times, high peak fluxes, and radius expansion episodes. ``Slow bursts'' occur in the Island State at lower accretion rates, have lower peak fluxes, higher fluences, longer decay times, and show no evidence of radius expansion. All five of the fast bursts, and none of the four slow bursts, show coherent oscillations near 524 Hz. We perform in-burst phase connection of the burst pulsations, which allows us to unambiguously characterize their frequency evolution. That evolution exhibits a variety of behaviors, including a sharp spin-down during one burst. Applying our phase models, we find that the pulsations are spectrally harder than the burst emission, with the strength of the pulsations increasing monotonically with photon energy. Coherently summing...

  5. Swift detection of an intermediately long X-ray burst from the very faint X-ray binary XMMU J174716.1-281048

    CERN Document Server

    Degenaar, N; Kaur, R

    2011-01-01

    We report on the Swift detection of a thermonuclear X-ray burst from the very-faint quasi-persistent neutron star X-ray binary XMMU J174716.1-281048, which triggered the satellite's Burst Alert Telescope (BAT) on 2010 August 13. Analysis of the BAT spectrum yields an observed bolometric peak flux of ~4.5E-8 erg/cm2/s, from which we infer a source distance of <8.4 kpc. Follow-up observations with Swift's X-ray Telescope (XRT) suggest that the event had a duration of ~3 h, and classifies as an intermediately long X-ray burst. This is only the second X-ray burst ever reported from this source. Inspection of Swift/XRT observations performed between 2007-2010 suggests that the 2-10 keV accretion luminosity of the system is only ~5E34 erg/s for an assumed distance of 8.4 kpc. Despite being transient, XMMU J174716.1-281048 appears to have been continuously active since its discovery in 2003.

  6. Long Type I X-ray Bursts and Neutron Star Interior Physics

    CERN Document Server

    Cumming, A; in 't Zand, J J M; Page, D; Cumming, Andrew; Macbeth, Jared; Page, Dany

    2005-01-01

    Superbursts are very energetic Type I X-ray bursts discovered in recent years by long term monitoring of X-ray bursters, believed to be due to unstable ignition of carbon in the deep ocean of the neutron star. A number of "intermediate duration" bursts have also been observed, probably associated with ignition of a thick helium layer. We investigate the sensitivity of these long X-ray bursts to the thermal profile of the neutron star crust and core. We first compare cooling models of superburst lightcurves with observations, and derive constraints on the ignition mass and energy release, and then calculate ignition models for superbursts and pure helium bursts, and compare to observations. The superburst lightcurves and ignition models imply that the carbon mass fraction is approximately 20% or greater in the fuel layer, constraining models of carbon production. However, the most important result is that when Cooper pairing neutrino emission is included in the crust, the temperature is too low to support unst...

  7. Soft X-ray Transmission Spectroscopy of Warm/Hot Intergalactic Medium: Mock Observation of Gamma-Ray Burst X-ray Afterglow

    CERN Document Server

    Kawahara, H; Sasaki, S; Suto, Y; Kawai, N; Mitsuda, K; Ohashi, T; Yamasaki, N; Kawahara, Hajime; Yoshikawa, Kohji; Sasaki, Shin; Suto, Yasushi; Kawai, Nobuyuki; Mitsuda, Kazuhisa; Ohashi, Takaya; Yamasaki, Noriko

    2005-01-01

    We discuss the detectability of Warm/Hot Intergalactic medium (WHIM) via the absorption lines toward bright gamma-ray burst (GRB) afterglows with future X-ray satellite missions like XEUS. We create mock absorption spectra for bright GRB afterglows ($\\sim 40$ per year over the entire sky) using a light-cone output of a cosmological hydrodynamic simulation. We assume that WHIM is under collisional and photo-ionization equilibrium. If we adopt the constant metallicity of $Z=0.1Z_\\odot$, approximately one O{\\sc vii} absorption line system with $>3\\sigma$ will be detected on average along a random line-of-sight up to $z=0.3$ if XEUS starts observing within a couple of hours after the GRB alert. However the above number is very sensitive to the adopted, and currently unknown, metallicity of the WHIM. We also discuss a feasibility of a follow-up observation for the emission line counterpart with a small dedicated X-ray mission like DIOS (Diffuse Intergalactic Oxygen Surveyor) and reliability of the estimate of the ...

  8. X-ray flares from dense shells formed in gamma-ray burst explosions

    CERN Document Server

    Hascoet, R; Daigne, F; Mochkovitch, R

    2015-01-01

    Bright X-ray flares are routinely detected by the Swift satellite during the early afterglow of gamma-ray bursts, when the explosion ejecta drives a blast wave into the external medium. We suggest that the flares are produced as the reverse shock propagates into the tail of the ejecta. The ejecta is expected to contain a few dense shells formed at an earlier stage of the explosion. We show an example of how such dense shells form and describe how the reverse shock interacts with them. A new reflected shock is generated in this interaction, which produces a short-lived X-ray flare. The model provides a natural explanation for the main observed features of the X-ray flares --- the fast rise, the steep power-law decline, and the characteristic peak duration \\Delta t /t= (0.1-0.3).

  9. Numbers of Electrons in Solar Flares as Deduced from Microwave and X-Ray Bursts

    Institute of Scientific and Technical Information of China (English)

    YU Xing-Feng; YAO Jin-Xing

    2001-01-01

    We discuss whether the numbers of x-ray and radio-produced electrons in solar flares are the same. The number of radio-produced electrons that is estimated with an inhomogeneous source increases by a factor of 103 - 104because of the inhomogeneity and the decreased magnetic field (B = 120 G) of the radio source. The number of x-ray-produced electrons decreases by a factor of 10 - 30 due to the increase of the number density of ions (3 × 1010 cm-3). These are the reasons why the number of radio-produced electrons is approximately equal tothat of x-ray-produced electrons in the 1981 April 27 burst.

  10. Deka-keV X-ray observations of solar bursts with WATCH/GRANAT: frequency distributions of burst parameters

    DEFF Research Database (Denmark)

    Crosby, N.; Vilmer, N.; Lund, Niels;

    1998-01-01

    Solar flare observations in the deka-keV range are performed by the WATCH experiment on board the GRANAT satellite. The WATCH experiment is presented, including the energy calibration as applied in the present work. The creation of the solar burst catalogue covering two years of observation...... is described and some examples of solar observations are given. The estimated energy releases in the flares presented here are found to extend below the range of hard X-ray flares which were previously studied by ISEE-3 and HXRBS/SMM detectors. The X-ray emitting component cannot be exclusively explained...... be observed as low as 10 keV. A statistical study is performed on the total WATCH solar database and frequency distributions are built on measured X-ray flare parameters. It is also investigated how the properties of these frequency distributions behave when subgroups of events defined by different ranges...

  11. X-ray spectra and atmospheric structures of bursting neutron stars

    International Nuclear Information System (INIS)

    I discuss atmospheric structures and emitted x-ray spectra of bursting neutron stars. The x-ray spectrum is deformed from the blackbody spectrum by Comptonization and by a strong energy dependence of absorptive opacities. The atmospheric structures deviate from those of the Eddington atmospheres due to the Compton heating-cooling. I construct color temperature vs. luminosity diagrams from the atmospheric models of neutron stars. Comparing these with observational ones, I obtain two relations among mass, radius, and distance of the x-ray bursters MXB 1636 - 536 and MXB 1608 - 522. I derive two possible sets of mass, radius, and distance of the x-ray burst source MXB 1636 - 536 taking into account of the 4.1-keV absorption line, theoretical mass-radius relation of the neutron star, and the distance to the galactic center. If the absorption line is due to Cr 23 M = 1.7 - 2.0 solar mass, R = 11 - 12 km, and d = 6.3 - 6.7 kpc, and if it is due to Fe 25, M = 1.8 - 2.1 solar mass, R = 8 - 10 km, and d = 5.8 - 6.4 kpc. (author)

  12. Effective absorbing column density in the gamma-ray burst afterglow X-ray spectra

    CERN Document Server

    Campana, S; Braito, V; Cusumano, G; D'Avanzo, P; D'Elia, V; Ghirlanda, G; Ghisellini, G; Melandri, A; Salvaterra, R; Tagliaferri, G; Vergani, S D

    2014-01-01

    We investigate the scaling relation between the observed amount of absorption in the X-ray spectra of Gamma Ray Burst (GRB) afterglows and the absorber redshift. Through dedicated numerical simulations of an ideal instrument, we establish that this dependence has a power law shape with index 2.4. However, for real instruments, this value depends on their low energy cut-off, spectral resolution and on the detector spectral response in general. We thus provide appropriate scaling laws for specific instruments. Finally, we discuss the possibility to measure the absorber redshift from X-ray data alone. We find that 10^5-10^6 counts in the 0.3-10 keV band are needed to constrain the redshift with 10% accuracy. As a test case we discuss the XMM-Newton observation of GRB 090618 at z=0.54. We are able to recover the correct redshift of this burst with the expected accuracy.

  13. Effective absorbing column density in the gamma-ray burst afterglow X-ray spectra

    Science.gov (United States)

    Campana, S.; Bernardini, M. G.; Braito, V.; Cusumano, G.; D'Avanzo, P.; D'Elia, V.; Ghirlanda, G.; Ghisellini, G.; Melandri, A.; Salvaterra, R.; Tagliaferri, G.; Vergani, S. D.

    2014-07-01

    We investigate the scaling relation between the observed amount of absorption in the X-ray spectra of gamma-ray burst afterglows and the absorber redshift. Through dedicated numerical simulations of an ideal instrument, we establish that this dependence has a power-law shape with index 2.4. However, for real instruments, this value depends on their low-energy cut-off, spectral resolution and on the detector spectral response in general. We thus provide appropriate scaling laws for specific instruments. Finally, we discuss the possibility to measure the absorber redshift from X-ray data alone. We find that 105-106 counts in the 0.3-10 keV band are needed to constrain the redshift with 10 per cent accuracy. As a test case, we discuss the XMM-Newton observation of GRB 090618 at z = 0.54. We are able to recover the correct redshift of this burst with the expected accuracy.

  14. The full curvature effect expected in early X-ray afterglow emission of gamma-ray bursts

    OpenAIRE

    Qin, Y. -P.

    2008-01-01

    We explore the influence of the full curvature effect on the flux of early X-ray afterglow of gamma-ray bursts (GRBs) in cases when the spectrum of the intrinsic emission is a power-law. We find that the well-known $t^{-(2+\\beta)}$ curve is present only when the intrinsic emission is extremely short or the emission arises from an exponential cooling. The time scale of this curve is independent of the Lorentz factor. The resulting light curve would contain two phases when the intrinsic emissio...

  15. Comprehensive study of the X-ray flares from gamma-ray bursts observed by Swift

    CERN Document Server

    Yi, Shuang-Xi; Yu, Hai; Wang, F Y; Mu, Hui-Jun; Lv, Lian-Zhong; Liang, En-Wei

    2016-01-01

    X-ray flares are generally supposed to be produced by the later central engine activities, and may share the similar physical origin with prompt emission of gamma-ray bursts (GRBs). In this paper, we have analyzed all significant X-ray flares from the GRBs observed by {\\em Swift} from April 2005 to March 2015. The catalog contains 468 bright X-ray flares, including 200 flares with redshifts. We obtain the fitting results of X-ray flares, such as start time, peak time, duration, peak flux, fluence, peak luminosity, and mean luminosity. The peak luminosity decreases with peak time, following a power-law behavior $L_p \\propto T_{peak,z}^{-1.27}$. The flare duration increases with peak time. The 0.3-10 keV isotropic energy of X-ray flares distribution is a lognormal peaked at $10^{51.2}$ erg. We also study the frequency distributions of flare parameters, including energies, durations, peak fluxes, rise times, decay times and waiting times. Power-law distributions of energies, durations, peak fluxes, and waiting t...

  16. Comparisons of Two- and Three-Dimensional Convection in Type I X-ray Bursts

    CERN Document Server

    Zingale, M; Nonaka, A; Almgren, A S; Bell, J B

    2014-01-01

    We perform the first detailed three-dimensional simulation of low Mach number convection preceding thermonuclear ignition in a mixed H/He X-ray burst. Our simulations include a moderate-sized, approximate network that captures hydrogen and helium burning up through rp-process breakout. We look in detail at the difference between two- and three-dimensional convective fields, including the details of the turbulent convection.

  17. Gamma-ray bursts and X-ray melting of material to form chondrules and planets

    CERN Document Server

    Duggan, P; Carr, A J; Winston, E; Vaughan, G; Hanlon, L; McBreen, S; Metcalfe, L; Kvick, A; Terry, A E

    2003-01-01

    Chondrules are millimeter sized objects of spherical to irregular shape that constitute the major component of chondritic meteorites that originate in the region between Mars and Jupiter and which fall to Earth. They appear to have solidified rapidly from molten or partially molten drops. The heat source that melted the chondrules remains uncertain. The intense radiation from a gamma-ray burst (GRB) is capable of melting material at distances up to 300 light years. These conditions were created in the laboratory for the first time when millimeter sized pellets were placed in a vacuum chamber in the white synchrotron beam at the European Synchrotron Radiation Facility. The pellets were rapidly heated in the X-ray and gamma-ray furnace to above 1400C melted and cooled. This process heats from the inside unlike normal furnaces. The melted spherical samples were examined with a range of techniques and found to have microstructural properties similar to the chondrules that come from meteorites. This experiment dem...

  18. Beacons in the sky: Classical novae vs. X-ray bursts

    International Nuclear Information System (INIS)

    Thermonuclear runaways are at the origin of some of the most energetic and frequent stellar cataclysmic events. In this review talk, we outline our understanding of the mechanisms leading to classical nova explosions and X-ray bursts, together with their associated nucleosynthesis. In particular, we focus on the interplay between nova outbursts and the Galactic chemical abundances (where 13C, 15N, and 17O constitute the likely imprints of many nova outbursts during the overall 10Gyr of Galactic history), the synthesis of radioactive nuclei of interest for gamma-ray astronomy (7Be-7Li, 22Na, or 26Al), the endpoint of nova nucleosynthesis, based on theoretical and observational grounds, and the recent discovery of presolar meteoritic grains, both in the Murchison and Acfer 094 meteorites, likely condensed in nova shells. Recent progress in the modeling of X-ray bursts as well as an insight into the input nuclear physics requests, for both novae and X-ray bursts, will also be presented. (orig.)

  19. The unusual X-ray light-curve of GRB 080307: the onset of the afterglow?

    CERN Document Server

    Page, K L; O'Brien, P T; Tanvir, N R; Osborne, J P; Zhang, B; Holland, S T; Levan, A J; Melandri, A; Starling, R L C; Bersier, D; Burrows, D N; Geach, J E; Maxted, P

    2009-01-01

    Swift-detected GRB 080307 showed an unusual smooth rise in its X-ray light-curve around 100 seconds after the burst, at the start of which the emission briefly softened. This `hump' has a longer duration than is normal for a flare at early times and does not demonstrate a typical flare profile. Using a two component power-law-to-exponential model, the rising emission can be modelled as the onset of the afterglow, something which is very rarely seen in Swift-X-ray light-curves. We cannot, however, rule out that the hump is a particularly slow early-time flare, or that it is caused by upscattered reverse shock electrons.

  20. A search for thermal X-ray signatures in gamma-ray bursts - I. Swift bursts with optical supernovae

    Science.gov (United States)

    Starling, R. L. C.; Page, K. L.; Pe'Er, A.; Beardmore, A. P.; Osborne, J. P.

    2012-12-01

    The X-ray spectra of gamma-ray bursts (GRBs) can generally be described by an absorbed power law. The landmark discovery of thermal X-ray emission in addition to the power law in the unusual GRB 060218, followed by a similar discovery in GRB 100316D, showed that during the first thousand seconds after trigger the soft X-ray spectra can be complex. Both the origin and prevalence of such spectral components still evade understanding, particularly after the discovery of thermal X-ray emission in the classical GRB 090618. Possibly most importantly, these three objects are all associated with optical supernovae (SNe), begging the question of whether the thermal X-ray components could be a result of the GRB-SN connection, possibly in the shock breakout. We therefore performed a search for blackbody components in the early Swift X-ray spectra of 11 GRBs that have or may have associated optical SNe, accurately recovering the thermal components reported in the literature for GRBs 060218, 090618 and 100316D. We present the discovery of a cooling blackbody in GRB 101219B/SN2010ma, and in four further GRB-SNe we find an improvement in the fit with a blackbody which we deem possible blackbody candidates due to case-specific caveats. All the possible new blackbody components we report lie at the high end of the luminosity and radius distribution. GRB 101219B appears to bridge the gap between the low-luminosity and the classical GRB-SNe with thermal emission, and following the blackbody evolution we derive an expansion velocity for this source of the order of 0.4c. We discuss potential origins for the thermal X-ray emission in our sample, including a cocoon model which we find can accommodate the more extreme physical parameters implied by many of our model fits.

  1. NuSTAR Observations of X-ray Bursts from the Magnetar 1E 1048.1-5937

    DEFF Research Database (Denmark)

    An, Hongjun; Kaspi, Victoria M.; Beloborodov, Andrei M.;

    2014-01-01

    We report the detection of eight bright X-ray bursts from the 6.5 s magnetar 1E 1048.1–5937, during a 2013 July observation campaign with the Nuclear Spectroscopic Telescope Array. We study the morphological and spectral properties of these bursts and their evolution with time. The bursts resulte...

  2. Optical and X-ray Rest-frame Light Curves of the BAT6 sample

    CERN Document Server

    Melandri, A; Rogantini, D; Salvaterra, R; Sbarufatti, B; Bernardini, M G; Campana, S; D'Avanzo, P; D'Elia, V; Fugazza, D; Ghirlanda, G; Ghisellini, G; Nava, L; Vergani, S D; Tagliaferri, G

    2014-01-01

    We present the rest-frame light curves in the optical and X-ray bands of an unbiased and complete sample of Swift long Gamma-Ray Bursts (GRBs), namely the BAT6 sample. The unbiased BAT6 sample (consisting of 58 events) has the highest level of completeness in redshift ($\\sim$ 95%), allowing us to compute the rest-frame X-ray and optical light curves for 55 and 47 objects, respectively. We compute the X-ray and optical luminosities accounting for any possible source of absorption (Galactic and intrinsic) that could affect the observed fluxes in these two bands. We compare the behaviour observed in the X-ray and in the optical bands to assess the relative contribution of the emission during the prompt and afterglow phases. We unarguably demonstrate that the GRBs rest-frame optical luminosity distribution is not bimodal, being rather clustered around the mean value Log(L$_{R}$) = 29.9 $\\pm$ 0.8 when estimated at a rest frame time of 12 hr. This is in contrast with what found in previous works and confirms that t...

  3. The X-ray quiescence of Swift J195509.6+261406 (GRB 070610): an optical bursting X-ray binary?

    NARCIS (Netherlands)

    N. Rea; P.G. Jonker; G. Nelemans; J.A. Pons; M.M. Kasliwal; S.R. Kulkarni; R. Wijnands

    2011-01-01

    We report on an ~63 ks Chandra observation of the X-ray transient Swift J195509.6+261406 discovered as the afterglow of what was first believed to be a long-duration gamma-ray burst (GRB 070610). The outburst of this source was characterized by unique optical flares on timescales of second or less,

  4. Dependence of X-Ray Burst Models on Nuclear Reaction Rates

    CERN Document Server

    Cyburt, R H; Heger, A; Johnson, E; Keek, L; Meisel, Z; Schatz, H; Smith, K

    2016-01-01

    X-ray bursts are thermonuclear flashes on the surface of accreting neutron stars and reliable burst models are needed to interpret observations in terms of properties of the neutron star and the binary system. We investigate the dependence of X-ray burst models on uncertainties in (p,$\\gamma$), ($\\alpha$,$\\gamma$), and ($\\alpha$,p) nuclear reaction rates using fully self-consistent burst models that account for the feedbacks between changes in nuclear energy generation and changes in astrophysical conditions. A two-step approach first identified sensitive nuclear reaction rates in a single-zone model with ignition conditions chosen to match calculations with a state-of-the-art 1D multi-zone model based on the {\\Kepler} stellar evolution code. All relevant reaction rates on neutron deficient isotopes up to mass 106 were individually varied by a factor of 100 up and down. Calculations of the 84 highest impact reaction rate changes were then repeated in the 1D multi-zone model. We find a number of uncertain reac...

  5. Mobile X-ray inspection of light weight materials

    Energy Technology Data Exchange (ETDEWEB)

    Ewert, Uwe; Redmer, Bernhard; Raedel, Christoph; Osterloh, Kurt [Federal Inst. for Materials Research and Testing (BAM), Berlin (Germany); Schnars, Ulf; Henrich, Rudolf; Schimmelmann, Olaf [Airbus, Bremen/Stade (Germany); Bavendiek, Klaus; Jahn, Mirko [YXLON International, Hamburg (Germany)

    2008-07-01

    Digital detectors such as phosphor imaging plates (IP) and digital detector arrays (DDA) allow radiographic inspection with higher efficiency and improved image quality in comparison to the classic film technique. Mobile X-ray flash tubes are used routinely for veterinarian and security applications. New high sensitive IPs and DDAs enable to apply them for inspection of light materials with low X-ray attenuation as in aluminium, plastics and composites. A versatile computed tomography (CT) system was developed for in situ inspection of large aircraft components under production conditions. A gate based planar computed tomograph was developed and tested for inspection of integrity of the stringer incorporation. Successful test trials were performed to prove the detection rate of cracks in embedded stringers. Honey comb structures of aircrafts have to be inspected for water inclusions during in-service inspections. Thermography is a powerful method for in house inspections when variations in temperature caused e.g. by sunshine can be excluded. A new X-ray diaphragm was developed for mobile back scatter measurements of large components. This method is insensitive to heat alterations in the field and thus can be applied also outdoors. (orig.)

  6. Mobile X-ray inspection of light weight materials

    International Nuclear Information System (INIS)

    Digital detectors such as phosphor imaging plates (IP) and digital detector arrays (DDA) allow radiographic inspection with higher efficiency and improved image quality in comparison to the classic film technique. Mobile X-ray flash tubes are used routinely for veterinarian and security applications. New high sensitive IPs and DDAs enable to apply them for inspection of light materials with low X-ray attenuation as in aluminium, plastics and composites. A versatile computed tomography (CT) system was developed for in situ inspection of large aircraft components under production conditions. A gate based planar computed tomograph was developed and tested for inspection of integrity of the stringer incorporation. Successful test trials were performed to prove the detection rate of cracks in embedded stringers. Honey comb structures of aircrafts have to be inspected for water inclusions during in-service inspections. Thermography is a powerful method for in house inspections when variations in temperature caused e.g. by sunshine can be excluded. A new X-ray diaphragm was developed for mobile back scatter measurements of large components. This method is insensitive to heat alterations in the field and thus can be applied also outdoors. (orig.)

  7. The discovery of X-ray bursts from a region in the constellation Norma

    International Nuclear Information System (INIS)

    A search through the first 15 months of data from X-ray detectors aboard the two Vela-5 satellites has revealed 20 count-rate enhancements at least 15 sigma above background. The detectors respond to X-rays in the energy band approx.3--12 keV. The collimator design permits direction determinations within a 12degree x 12degree error box. All of the observations are consistent with short X-ray bursts from distant point sources but not with incident charged-particle fluxes or with spacecraft electronic noise. Eleven of the observations above 15 sigma can be attributed to 10 X-ray flares (one outburst was observed by both spacecraft) located in a region centered at αapprox.16/sup h/, deltaapprox.-53degree in the constellation Norma. Another two of these 10 flares seen above the 15 sigma level were seen by the second spacecraft at levels of 9 sigma and 10 sigma. The observations are consistent with a single object as the source of all 10 outbursts. The most intense of these Norma flares was approximately 3/4 of the quiet phase Sco X-1 intensity. Flare durations were observed to be more than 2 s and less than 128 s for all of the events. The spectra varied considerably but were relatively hard compared to Sco X-1

  8. GeV-TeV and X-ray flares from gamma-ray burst

    CERN Document Server

    Wang, X Y; Mészáros, P; Li, Zhuo; Meszaros, Peter; Wang, Xiang-Yu

    2006-01-01

    The recent detection of delayed X-ray flares during the afterglow phase of gamma-ray bursts (GRBs) suggests an inner-engine origin, at radii inside the deceleration radius characterizing the beginning of the forward shock afterglow emission. Given the observed temporal overlapping between the flares and afterglows, there must be inverse Compton (IC) emission arising from such flare photons scattered by forward shock afterglow electrons. We find that this IC emission produces GeV-TeV flares, which may be detected by GLAST and ground-based TeV telescopes. We speculate that this kind of emission may already have been detected by EGRET from a very strong burst--GRB940217, if it had a bright X-ray flare at the time of its delayed GeV emission. The enhanced cooling of the forward shock electrons by the X-ray flare photons may suppress the synchrotron emission of the afterglows during the flare period. The detection of GeV-TeV flares combined with low energy observations may help to constrain the poorly known magnet...

  9. Note: Construction of x-ray scattering and x-ray absorption fine structure beamline at the Pohang Light Source

    International Nuclear Information System (INIS)

    A new hard x-ray beamline, 10B KIST-PAL beamline (BL10B), has been designed and constructed at the Pohang Light Source (PLS) in Korea. The beamline, operated by Pohang Accelerator Laboratory-Korean Institute of Science and Technology consortium, is dedicated to x-ray scattering (XRS) and x-ray absorption fine structure (XAFS) experiments. X rays with photon energies from 4.0 to 16.0 keV are delivered to the experimental station passing a collimating mirror, a fixed-exit double-crystal Si(111) monochromator, and a toroidal mirror. Basic experimental equipments for XAFS measurement, a high resolution diffractometry, an image plate detector system, and a hot stage have been prepared for the station. From our initial commissioning and performance testing of the beamline, it is observed that BL10B beamline can perform XRS and XAFS measurements successfully.

  10. Constraining cosmological parameters by Gamma Ray Burst X - ray afterglow lightcurves

    CERN Document Server

    Cardone, V F; Capozziello, S; Willingale, R

    2010-01-01

    We present the Hubble diagram (HD) of 66 Gamma Ray Bursts (GRBs) derived using only data from their X - ray afterglow lightcurve. To this end, we use the recently updated L_X - T_a correlation between the break time T_a and the X - ray luminosity L_X measured at T_a calibrated from a sample of Swift GRBs with lightcurves well fitted by the Willingale et al. (2007) model. We then investigate the use of this HD to constrain cosmological parameters when used alone or in combination with other data showing that the use of GRBs leads to constraints in agreement with previous results in literature. We finally argue that a larger sample of high luminosity GRBs can provide a valuable information in the search for the correct cosmological model.

  11. The Early X-ray Afterglows of Optically Bright and Dark Gamma-Ray Bursts

    Institute of Scientific and Technical Information of China (English)

    Yi-Qing Lin

    2006-01-01

    A systematic study on the early X-ray afterglows of both optically bright and dark gamma-ray bursts (B-GRBs and D-GRBs) observed by Swift is presented. Our sample includes 25 GRBs of which 13 are B-GRBs and 12 are D-GRBs. Our results show that the distributions of the X-ray afterglow fluxes (Fx), the gamma-ray fluxes (Sγ), and the ratio (Rγ,X) are similar for the two kinds of GRBs, that any observed differences should be simply statistical fluctuation. These results indicate that the progenitors of the two kinds of GRBs are of the same population with comparable total energies of explosion. The suppression of optical emission in the D-GRBs should result from circumburst but not from their central engine.

  12. X-ray flares of γ-ray bursts: Quakes of solid quark stars?

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A star-quake model is proposed to understand X-ray flares of both long and short γ-ray bursts (GRBs) in a solid quark star regime. Two kinds of central engines for GRBs are available if pulsar-like stars are actually (solid) quark stars, i.e., the SNE-type GRBs and the SGR-type GRBs. It is found that a quark star could be solidified about 103 to 106 s later after its birth if the critical temperature of phase transi- tion is a few Metga-electron-volts, and then a new source of free energy (i.e., elastic and gravitational ones, rather than rotational or magnetic energy) could be possible to power GRB X-ray flares.

  13. X-Ray Flares of Gamma-Ray Bursts: Quakes of Solid Quark Stars?

    CERN Document Server

    Xu, Renxin

    2008-01-01

    We propose a star-quake model to understand X-ray flares of both long and short Gamma-ray bursts (GRBs) in a solid quark star regime. Two kinds of central engines for GRBs are available if pulsar-like stars are actually (solid) quark stars, i.e., the SNE-type GRBs and the SGR-type GRBs. It is found that a quark star could be solidified about 10^3 to 10^6 s later after its birth if the critical temperature of phase transition is a few MeV, and then a new source of free energy (i.e., elastic and gravitational ones, rather than rotational or magnetic energy) could be possible to power GRB X-ray flares.

  14. Timing analysis of hard X-ray emission and 22 GHz flux and polarization in a solar burst

    International Nuclear Information System (INIS)

    A solar flare occurring on 26 February 1981 at 1932 UT was observed simultaneously, in hard X-rays and microwaves with a time resolution of a fraction of a second. The X-ray observations were made with the Hard X-ray Monitor on Hinotori, and the microwave observations were made at 22 GHz with the 13.7 m Itapetinga mm-wave antenna. Timing accuracy was restricted to 62.5 ms, the best time resolution obtained in hard X-rays for this burst. It is found that: (a) all 22 GHz flux structures were delayed by 0.2 - 0.9 second relative to similar structures in hard X-rays throughout the burst duration; (b) different burst structures showed different delays, suggesting that they are independent of each other; (c) the time structures of the degree of polarization at 22 GHz precede the total microwave flux time structures by 0.1-0.5 sec; (d) The time evolutions of time delays of microwaves with respect to hard X-rays and also the degree of microwave polarization show fluctuations with are not clearly related to any other time structures. If it is taken mean values for the 32 sec burst duration, it is found that hard X-ray emission precedes the degree of microwave polarization by 450 ms, which in turn precedes the total microwave flux by 110 ms. (Author)

  15. On the Late-Time Spectral Softening Found in X-ray Afterglows of Gamma-Ray Bursts

    CERN Document Server

    Wang, Yuan-Zhu; Shao, Lang; Liang, En-Wei; Lu, Zu-Jia

    2016-01-01

    Strong spectral softening has been revealed in the late X-ray afterglows of some gamma-ray bursts (GRBs). The scenario of X-ray scattering around circum-burst dusty medium has been supported by previous works due to its overall successful prediction of both the temporal and spectral evolution of some X-ray afterglows. To further investigate the observed feature of spectral softening, we now systematically search the X-ray afterglows detected by X-Ray Telescope (XRT) of Swift and collect twelve GRBs with significant late-time spectral softening. We find that dust scattering could be the dominant radiative mechanism for these X-ray afterglows regarding their temporal and spectral features. For some well observed bursts with high-quality data, their time-resolved spectra could be well produced within the scattering scenario by taking into account the X-ray absorption from circum-burst medium. We also find that during spectral softening the power-law index in the high energy end of the spectra does not vary much....

  16. Possible hard X-ray shortages in bursts from KS 1731-260 and 4U 1705-44

    CERN Document Server

    Ji, Long; Chen, YuPeng; Zhang, Shuang-Nan; Kretschmar, Peter; Wang, Jian-Min; Li, Jian

    2014-01-01

    Aims: A hard X-ray shortage, implying the cooling of the corona, was observed during bursts of IGR J17473-272, 4U 1636-536, Aql X-1, and GS 1826-238. Apart from these four sources, we investigate here an atoll sample, in which the number of bursts for each source is larger than 5, to explore the possible additional hard X-ray shortage during {\\it Rossi X-ray timing explorer (RXTE)} era. Methods: According to the source catalog that shows type-I bursts, we analyzed all the available pointing observations of these sources carried out by the {\\it RXTE} proportional counter array (PCA). We grouped and combined the bursts according to their outburst states and searched for the possible hard X-ray shortage while bursting. Results: We found that the island states of KS 1731-260 and 4U 1705-44 show a hard X-ray shortage at significant levels of 4.5 and 4.7 $\\sigma$ and a systematic time lag of $0.9 \\pm 2.1$ s and $2.5 \\pm 2.0$ s with respect to the soft X-rays, respectively. While in their banana branches and other s...

  17. Classical novae and type I X-ray bursts: Challenges for the 21st century

    International Nuclear Information System (INIS)

    Classical nova explosions and type I X-ray bursts are the most frequent types of thermonuclear stellar explosions in the Galaxy. Both phenomena arise from thermonuclear ignition in the envelopes of accreting compact objects in close binary star systems. Detailed observations of these events have stimulated numerous studies in theoretical astrophysics and experimental nuclear physics. We discuss observational features of these phenomena and theoretical efforts to better understand the energy production and nucleosynthesis in these explosions. We also examine and summarize studies directed at identifying nuclear physics quantities with uncertainties that significantly affect model predictions

  18. Internal energy dissipation of gamma-ray bursts observed with Swift: Precursors, prompt gamma-rays, extended emission, and late X-ray flares

    International Nuclear Information System (INIS)

    We jointly analyze the gamma-ray burst (GRB) data observed with Burst Alert Telescope (BAT) and X-ray Telescope on board the Swift mission to present a global view on the internal energy dissipation processes in GRBs, including precursors, prompt gamma-ray emission, extended soft gamma-ray emission, and late X-ray flares. The Bayesian block method is utilized to analyze the BAT light curves to identify various emission episodes. Our results suggest that these emission components likely share the same physical origin, which is the repeated activation of the GRB central engine. What we observe in the gamma-ray band may be a small part of more extended underlying activities. The precursor emission, which is detected in about 10% of Swift GRBs, is preferably detected in those GRBs that have a massive star core-collapse origin. The soft extended emission tail, on the other hand, is preferably detected in those GRBs that have a compact star merger origin. Bright X-ray emission is detected during the BAT quiescent phases prior to subsequent gamma-ray peaks, implying that X-ray emission may be detectable prior the BAT trigger time. Future GRB alert instruments with soft X-ray capability are essential for revealing the early stages of GRB central engine activities, and shedding light on jet composition and the jet launching mechanism in GRBs.

  19. White-light flares, Hard X-Rays, and Heights

    Science.gov (United States)

    Martinez Oliveros, Juan Carlos; Hudson, Hugh S.; Krucker, Sam

    2016-05-01

    The white-light continuum of a solar flare was the first manifestation of a solar flare ever detected. Nevertheless, its mechanisms remain unknown, even today. Improved observations confirm the identification of white-light continuum emission and hard X-rays during the impulsive phase of a solar flare, both in space and in time, to within the observational limits. Two events observed near the limb, but not occulted by it (SOL2011-02-24 and SOL2012-02-18), show that these emissions appear to have physical heights lower than predicted by models by hundreds of kms, referring height to the location of optical-depth unity at disk center in the 500 nm continuum. We describe these results and place them in the context of the three extreme-limb events (within about 1o) reported by Krucker et al. (2015). The electrons responsible for hard X-ray bremsstrahlung coincide with the most intense flare energy release, but we do not presently understand the physics of energy transport nor the nature of particle acceleration apparently taking place at heights below the preflare temperature minimum.

  20. Novel Light-Weight X-ray Optics for Future X-ray Telescopes

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Pína, L.; Inneman, A.; Brožek, V.

    Berlin : Springer, 2007 - (Lobanov, A.; Zensus , J.; Cesarsky, C.; Diamond, P.), S.75-75 ISBN 978-3-540-39755-7. - (ESO Astrophysics Symposia). [Exploring the Cosmic Frontier: Astrophysical Instruments for the 21st Century. Berlin (DE), 18.05.2004-21.05.2004] R&D Projects: GA AV ČR IAAX01220701; GA MŠk ME 918 Institutional research plan: CEZ:AV0Z10030501 Keywords : X-ray optics * X-ray telescopes Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  1. A Comprehensive Study of the X-ray Bursts from the Magnetar Candidate 1E 2259+586

    CERN Document Server

    Gavriil, F P; Woods, P M; Gavriil, Fotis P.; Kaspi, Victoria M.; Woods, Peter M.

    2003-01-01

    We present a statistical analysis of the X-ray bursts observed from the 2002 June 18 outburst of the Anomalous X-ray Pulsar (AXP) 1E 2259+586, observed with the Proportional Counter Array (PCA) aboard the Rossi X-ray Timing Explorer. We show that the properties of these bursts are similar to those of Soft Gamma-Repeaters (SGRs). The similarities we find are the burst durations follow a log-normal distribution which peaks at 99 ms, the differential burst fluence distribution is well described by a power law of index -1.7, the burst fluences are positively correlated with the burst durations, the distribution of waiting times is well described by a log-normal distribution of mean 47 s, and the bursts are generally asymmetric with faster rise than fall times. However, we find several quantitative differences between the AXP and SGR bursts. Specifically, the AXP bursts we observed exhibit a wider range of durations, the correlation between burst fluence and duration is flatter than for SGRs, the observed AXP burs...

  2. Periodicity Analysis of X-ray Light Curves of SS 433

    Science.gov (United States)

    Wang, J. Y.; Lu, X. L.; Zhao, Q. W.; Dong, D. Q.; Lao, B. Q.; Lu, Y.; Wei, Y. H.; Wu, X. C.; An, T.

    2016-03-01

    SS 433 is the only X-ray binary to date that was detected to have a pair of well-collimated jets, and its orbital period, super orbital period, and nutation period were all detected at the same time. The study on the periodic X-ray variabilities is helpful for understanding its dynamic process of the central engine and the correlation with other bands. In the present paper, two time series analysis techniques, Lomb-Scargle periodogram and weighted wavelet Z-transform, are employed to search for the periodicities from the Swift/BAT (Burst Alert Telescope)(15--50 keV) and RXTE/ASM (Rossi X-Ray Timing Explorer/All-Sky Monitor)(1.5--3, 3--5 and 5--12 keV) light curves of SS 433, and the Monte Carlo simulation is performed. For the 15--50 keV energy band, five significant periodic signals are detected, which are P_1(˜6.29 d), P_2 (˜6.54 d), P_3 (˜13.08 d), P_4 (˜81.50 d), and P_5 (˜162.30 d). For the 3--5 and 5--12 keV energy bands, periodic signals P_3 (˜13 d) and P_5 (˜162 d) are detected in both energy bands. However, for the 1.5--3 keV energy band, no significant periodic signal is detected. P_5 has the strongest periodic signal in the power spectrum for all the energy bands of 3--5, 5--12, and 15--50 keV, and it is consistent with that obtained by previous study in optical band. Further, due to the existence of relativistic radio jets, the X-ray and optical band variability of P_5 (˜162 d) is probably related to the precession of the relativistic jets. High coherence between X-ray and optical light curves may also imply that the X-ray and optical emissions are of the same physical origin. P_3 shows a good agreement with the orbital period (˜13.07 d) first obtained by previous study, and P_2 and P_4 are the high frequency harmonic components of P_3 and P_5, respectively. P_1 is detected from the power spectrum of 15--50 keV energy band only, and it is consistent with the systematic nutation period. As the power of energy band decreases (from hard X-ray to

  3. The eclipsing bursting X-ray binary EXO 0748-676 revisited by XMM-Newton

    CERN Document Server

    Bonnet-Bidaud, J M; Ferrando, P; Bennie, P J; Kendziorra, E

    2001-01-01

    The bright eclipsing and bursting low-mass X-ray binary EXO 0748-676 has been observed at several occasions by XMM-Newton during the initial calibration and performance verification (CAL/PV) phase. We present here the results obtained from observations with the EPIC cameras. Apart from several type-I X-ray bursts, the source shows a high degree of variability with the presence of soft flares. The wide energy coverage and high sensitivity of XMM-Newton allows for the first time a detailed description of the spectral variability. The source is found to be the superposition of a central (~2 10^8 cm) Comptonized emission, most probably a corona surrounding the inner edge of an accretion disk, associated with a more extended (~3 10^10 cm) thermal halo at a typical temperature of ~0.6 keV with an indication of non-solar abundances. Most of the variations of the source can be accounted for by a variable absorption affecting only the central comptonized component and reaching up to NH ~1.3 10^23 cm^{-2}. The characte...

  4. Fast and slow magnetic deflagration fronts in Type I X-ray bursts

    CERN Document Server

    Cavecchi, Yuri; Watts, Anna L; Braithwaite, Jonathan

    2015-01-01

    Type I X-ray bursts are produced by thermonuclear runaways that develop on accreting neutron stars. Once one location ignites, the flame propagates across the surface of the star. Flame propagation is fundamental in order to understand burst properties like rise time and burst oscillations. Previous work quantified the effects of rotation on the front, showing that the flame propagates as a deflagration and that the front strongly resembles a hurricane. However the effect of magnetic fields was not investigated, despite the fact that magnetic fields strong enough to have an effect on the propagating flame are expected to be present on many bursters. In this paper we show how the coupling between fluid layers introduced by an initially vertical magnetic field plays a decisive role in determining the character of the fronts that are responsible for the Type I bursts. In particular, on a star spinning at 450 Hz (typical among the bursters) we test seed magnetic fields of $10^{7} - 10^{10}$ G and find that for th...

  5. EVIDENCE FOR NEW RELATIONS BETWEEN GAMMA-RAY BURST PROMPT AND X-RAY AFTERGLOW EMISSION FROM 9 YEARS OF SWIFT

    International Nuclear Information System (INIS)

    When a massive star explodes as a gamma-ray burst (GRB), information about the explosion is retained in the properties of the prompt and afterglow emission. We report on new relations between the prompt and X-ray afterglow emission of Swift-detected GRBs found from Burst Alert Telescope (BAT) and X-Ray Telescope data covering 2004 December to 2013 August (754 in total). These relations suggest that the prompt and afterglow emission are closely linked. In particular, we find very strong correlations between the BAT 15-150 keV T 90 and the break times before and after the plateau phase in the 0.3-10 keV X-ray afterglow light curves. We also find a strong anticorrelation between the photon index of the GRB prompt emission and the X-ray spectral slope of the afterglow. Moreover, anticorrelations exist between the rest-frame peak energy in the prompt emission E peak, z and the X-ray afterglow decay slope during the plateau phase and the break times after the plateau phase. The rest- frame break times before and after the plateau phase are also anticorrelated with the rest-frame 15-150 keV luminosity and the isotropic energy during the prompt emission. A principal component analysis suggests that the GRB properties are primarily driven by the luminosity/energy release in the 15-150 keV band. Luminosity functions derived at different redshifts from a log N-log S analysis indicate that the density of bright bursts is significantly lower in the local universe than in the universe at z ≈ 3, where the density of bright GRBs peaks. Using cluster analysis, we find that the duration of BAT-detected short GRBs is less than 1 s. We also present a catalog of all Swift onboard-detected bursts

  6. Parametric X-ray generation using the burst-mode beam at LEBRA and the feasibility of the application

    International Nuclear Information System (INIS)

    At the Laboratory for Electron Beam Research and Application (LEBRA), the parametric X-ray (PXR) beam produced by using the burst-mode beam from the electron linac was observed and the several application experiments were actually performed. In the case of the 64 division mode corresponding to the bunch period of 22.4 ns, the macropulse beam current was approximately one fifth of that of the conventional full bunch mode. The result of the imaging using the PXR beam agrees with the PXR yield proportional to the beam current. Analyzer-based phase-contrast imaging and dispersive X-ray absorption spectroscopy were also carried out using the burst-mode beam. As the result, no serious problem was observed with respect to the X-ray beam quality. Thus, it is expected that the time-resolved experiments with the resolution of 1 ns will be possible using the burst-mode PXR beam. (author)

  7. Determining Neutron Star Properties by Fitting Oblate Schwarzschild Waveforms To X-ray Burst Oscillations

    CERN Document Server

    Miller, M Coleman

    2014-01-01

    We have developed sophisticated new Bayesian analysis methods that enable us to estimate quickly the masses and radii of rapidly rotating, oblate neutron stars using the energy-resolved waveforms of their X-ray burst oscillations and to determine the uncertainties in these mass and radius estimates. We demonstrate these methods by generating and analyzing the energy-resolved burst oscillation waveforms that would be produced by a hot spot on various rapidly rotating, oblate stars, using the analytic implementation of the oblate-star Schwarzschild-spacetime (OS) approximation introduced by Morsink et al. 2007. In generating these synthetic data, we assume that 10$^6$ counts have been collected from the hot spot and that the background is $9\\times10^6$ counts. This produces a realistic modulation amplitude and a total number of counts comparable to the number that could be obtained by future space missions, by combining data from many bursts from a given star. We compute the joint posterior distribution of the ...

  8. The Definitive X-Ray Light Curve of Swift J164449.3+573451

    Science.gov (United States)

    Mangano, V.; Burrows, D. N.; Sbarufatti, B.; Cannizzo, J. K.

    2016-02-01

    On 2011 March 28, the Swift Burst Alert Telescope triggered on an object that had no analog in over six years of Swift operations. Follow-up observations by the Swift X-ray Telescope (XRT) found a new, bright X-ray source covering three orders of magnitude in flux over the first few days, that was much more persistent (and variable) than gamma-ray burst afterglows. Ground-based spectroscopy found a redshift of 0.35, implying extremely high luminosity, with integrated isotropic-equivalent energy output in the X-ray band alone exceeding 1053 erg in the first two weeks after discovery. Strong evidence for a collimated outflow or beamed emission was found. The observational properties of this object are unlike anything ever before observed. We interpret these unique properties as the result of emission from a relativistic jet produced in the aftermath of the tidal disruption of a main sequence star by a massive black hole (BH) in the center of the host galaxy. The source decayed slowly as the stellar remnants were accreted onto the BH, before abruptly shutting off. Here we present the definitive XRT team light curve for Swift J164449.3+573451 and discuss its implications. We show that the unabsorbed flux decayed roughly as a {t}-1.5 power law up to 2012 August 17. The steep turnoff of an order of magnitude in 24 hr seems to be consistent with the shutdown of the jet as the accretion disk transitioned from a thick disk to a thin disk. Swift continues to monitor this source in case the jet reactivates.

  9. New soft gamma-ray bursts in the BATSE records and spectral properties of X-ray rich bursts

    CERN Document Server

    Tikhomirova, Y; Kozyreva, A V; Poutanen, J; Tikhomirova, Yana; Stern, Boris; Kozyreva, Alexandra; Poutanen, Juri

    2006-01-01

    A population of X-ray dominated gamma-ray bursts (GRBs) observed by Ginga, BeppoSax and Hete-2 should be represented in the BATSE data as presumably soft bursts. We have performed a search for soft GRBs in the BATSE records in the 25--100 keV energy band. A softness of a burst spectrum can be a reason why it has been missed by the on-board procedure and previous searches for untriggered GRBs tuned to 50--300 keV range. We have found a surprisingly small number (~20/yr down to 0.1 ph cm$^{-2}$ s$^{-1}$) of soft GRBs where the count rate is dominated by 25--50 keV energy channel. This fact as well as the analysis of HETE-2 and common BeppoSAX/BATSE GRBs indicates that the majority of GRBs with a low Epeak has a relatively hard tail with the high-energy power-law photon index >-3. An exponential cutoff in GRB spectra below 20 keV may be a distinguishing feature separating non-GRB events.

  10. A time - luminosity correlation for Gamma Ray Bursts in the X - rays

    CERN Document Server

    Dainotti, M G; Capozziello, S

    2008-01-01

    Gamma ray bursts (GRBs) have recently attracted much attention as a possible way to extend the Hubble diagram to very high redshift. However, the large scatter in their intrinsic properties prevents directly using them as distance indicator so that the hunt is open for a relation involving an observable property to standardize GRBs in the same way as the Phillips law makes it possible to use Type Ia Supernovae (SNeIa) as standardizable candles. We use here the data on the X - ray decay curve and spectral index of a sample of GRBs observed with the Swift satellite. These data are used as input to a Bayesian statistical analysis looking for a correlation between the X - ray luminosity L_X(T_a) and the time constant T_a of the afterglow curve. We find a linear relation between \\log{[L_X(T_a)]} and \\log{[T_a/(1+z)]} with an intrinsic scatter sigma_{int} = 0.33 comparable to previously reported relations. Remarkably, both the slope and the intrinsic scatter are almost independent on the matter density Omega_M and ...

  11. Absorption features in the spectra of X-ray bursting neutron stars

    CERN Document Server

    Rauch, Thomas; Werner, Klaus

    2008-01-01

    The discovery of photospheric absorption lines in XMM-Newton spectra of the X-ray bursting neutron star in EXO0748-676 by Cottam and collaborators allows us to constrain the neutron star mass-radius ratio from the measured gravitational redshift. A radius of R=9-12km for a plausible mass range of M=1.4-1.8Msun was derived by these authors. It has been claimed that the absorption features stem from gravitationally redshifted (z=0.35) n=2-3 lines of H- and He-like iron. We investigate this identification and search for alternatives. We compute LTE and non-LTE neutron-star model atmospheres and detailed synthetic spectra for a wide range of effective temperatures (effective temperatures of 1 - 20MK) and different chemical compositions. We are unable to confirm the identification of the absorption features in the X-ray spectrum of EXO0748-676 as n=2-3 lines of H- and He-like iron (Fe XXVI and Fe XXV). These are subordinate lines that are predicted by our models to be too weak at any effective temperature. It is m...

  12. Windowless microfluidic platform based on capillary burst valves for high intensity x-ray measurements

    International Nuclear Information System (INIS)

    We propose and describe a microfluidic system for high intensity x-ray measurements. The required open access to a microfluidic channel is provided by an out-of-plane capillary burst valve (CBV). The functionality of the out-of-plane CBV is characterized with respect to the diameter of the windowless access hole, ranging from 10 to 130 μm. Maximum driving pressures from 22 to 280 mbar corresponding to refresh rates of the exposed sample from 300 Hz to 54 kHz is demonstrated. The microfluidic system is tested at beamline ID09b at the ESRF synchrotron radiation facility in Grenoble, and x-ray scattering measurements are shown to be feasible and to require only very limited amounts of sample, <1 ml/h of measurements without recapturing of sample. With small adjustments of the present chip design, scattering angles up to 30 deg. can be achieved without shadowing effects and integration on-chip mixing and spectroscopy appears straightforward.

  13. X-ray bursting neutron star atmosphere models: spectra and color corrections

    CERN Document Server

    Suleimanov, V; Werner, K

    2010-01-01

    X-ray bursting neutron stars in low mass X-ray binaries constitute an appropriate source class to constrain masses and radii of neutron stars, but a sufficiently extended set of corresponding model atmospheres is necessary for these investigations. We computed such a set of model atmospheres and emergent spectra in a plane-parallel, hydrostatic, and LTE approximation with Compton scattering taken into account. The models were calculated for six different chemical compositions: pure hydrogen and pure helium atmospheres, and atmospheres with solar mix of hydrogen and helium, and various heavy element abundances Z = 1, 0.3, 0.1, and 0.01 Z_sun. For each chemical composition the models are computed for three values of surface gravity, log g =14.0, 14.3, and 14.6, and for 20 values of the luminosity in units of the Eddington luminosity, L/L_Edd, in the range 0.001--0.98. The emergent spectra of all models are redshifted and fitted by a diluted blackbody in the RXTE/PCA 3--20 keV energy band, and corresponding valu...

  14. X-raying Extended emission and rapid decay of short gamma-ray bursts

    CERN Document Server

    Kagawa, Yasuaki; Sawano, Tatsuya; Toyanago, Asuka; Nakamura, Takashi; Takahashi, Keitaro; Kashiyama, Kazumi; Ioka, Kunihito

    2015-01-01

    Extended emission is a mystery in short gamma-ray bursts (SGRBs). By making time resolved spectral analyses of brightest eight events observed by {\\it Swift} XRT, we obviously classify the early X-ray emission of SGRBs into two types. One is the extended emission with exponentially rapid decay, which shows significant spectral softening during hundreds seconds since the SGRB trigger and is also detected by {\\it Swift}-BAT. The other is a dim afterglow only showing power-law decay over $10^4$ s. The correlations between the temporal decay and spectral indices of the extended emissions are inconsistent with the $\\alpha$-$\\beta$ correlation expected for the high-latitude curvature emission from a uniform jet. The observed too-rapid decay suggests the emission from a photosphere or a patchy surface, and manifests the stopping central engine via such as magnetic reconnection at the black hole.

  15. The influence of accretion geometry on the spectral evolution during thermonuclear (type-I) X-ray bursts

    CERN Document Server

    Kajava, Jari J E; Latvala, Outi-Marja; Pursiainen, Miika; Poutanen, Juri; Suleimanov, Valery F; Revnivtsev, Mikhail G; Kuulkers, Erik; Galloway, Duncan K

    2014-01-01

    Neutron star (NS) masses and radii can be estimated from observations of photospheric radius-expansion X-ray bursts, provided the chemical composition of the photosphere, the spectral colour-correction factors in the observed luminosity range, and the emission area during the bursts are known. By analysing 246 X-ray bursts observed by the Rossi X-ray Timing Explorer from 11 low-mass X-ray binaries, we find a dependence between the persistent spectral properties and the time evolution of the black body normalisation during the bursts. All NS atmosphere models predict that the colour-correction factor decreases in the early cooling phase when the luminosity first drops below the limiting Eddington value, leading to a characteristic pattern of variability in the measured blackbody normalisation. However, the model predictions agree with the observations for most bursts occurring in hard, low-luminosity, 'island' spectral states, but rarely during soft, high-luminosity, 'banana' states. The observed behaviour may...

  16. Amplified high order harmonic light for high coherent x-ray laser

    International Nuclear Information System (INIS)

    We proposed a method to generate high spatial and temporal coherent x-ray laser, in which high order harmonic light is used as a seed light of a laser-produced x-ray amplifier. The high order harmonic light is very suitable for this purpose because it has high spatial and temporal coherence. In this report, we conducted an experiment for the amplification of the 29th order harmonic light of the Ti;Sapphire laser with the neon-like manganese x-ray laser medium (λ=26.9 nm) pumped by the Nd:Glass laser. The divergence of Ne-like Mu x-ray laser with the seed light was preserved form the divergence of the seed light. We succeed in amplification of the harmonic light for the purpose of high coherent x-ray laser. (author)

  17. Implications of the Early X-Ray Afterglow Light Curves of Swift GRBs

    Energy Technology Data Exchange (ETDEWEB)

    Granot, Jonathan; /KIPAC, Menlo Park; Konigl, Arieh; /Chicago U., Astron. Astrophys. Ctr. /Chicago U., EFI; Piran, Tsvi; /Hebrew U.

    2006-01-17

    According to current models, gamma-ray bursts (GRBs) are produced when the energy carried by a relativistic outflow is dissipated and converted into radiation. The efficiency of this process, {epsilon}{sub {gamma}}, is one of the critical factors in any GRB model. The X-ray afterglow light curves of Swift GRBs show an early stage of flattish decay. This has been interpreted as reflecting energy injection. When combined with previous estimates, which have concluded that the kinetic energy of the late ({approx}> 10 hr) afterglow is comparable to the energy emitted in {gamma}-rays, this interpretation implies very high values of {epsilon}{sub {gamma}}, corresponding to {approx}> 90% of the initial energy being converted into {gamma}-rays. Such a high efficiency is hard to reconcile with most models, including in particular the popular internal-shocks model. We re-analyze the derivation of the kinetic energy from the afterglow X-ray flux and re-examine the resulting estimates of the efficiency. We confirm that, if the flattish decay arises from energy injection and the pre-Swift broad-band estimates of the kinetic energy are correct, then {epsilon}{sub {gamma}} {approx}> 0.9. We discuss various issues related to this result, including an alternative interpretation of the light curve in terms of a two-component outflow model, which we apply to the X-ray observations of GRB 050315. We point out, however, that another interpretation of the flattish decay--a variable X-ray afterglow efficiency (e.g., due to a time dependence of afterglow shock microphysical parameters)--is possible. We also show that direct estimates of the kinetic energy from the late X-ray afterglow flux are sensitive to the assumed values of the shock microphysical parameters and suggest that broad-band afterglow fits might have underestimated the kinetic energy (e.g., by overestimating the fraction of electrons that are accelerated to relativistic energies). Either one of these possibilities implies a

  18. The 2006-2007 Active Phase of Anomalous X-ray Pulsar 4U 0142+61: Radiative and Timing Changes, Bursts, and Burst Spectral Features

    CERN Document Server

    Gavriil, Fotis P; Kaspi, Victoria M

    2009-01-01

    After at least 6 years of quiescence, Anomalous X-ray Pulsar (AXP) 4U 0142+61 entered an active phase in 2006 March that lasted several months and included six X-ray bursts as well as many changes in the persistent X-ray emission. The bursts, the first seen from this AXP in >11 years of Rossi X-ray Timing Explorer monitoring, all occurred in the interval between 2006 April 6 and 2007 February 7. The burst durations ranged from 8-3x10^3 s. The first five burst spectra are well modeled by blackbodies, with temperatures kT ~ 2-6 keV. However, the sixth burst had a complicated spectrum that is well characterized by a blackbody plus three emission features whose amplitude varied throughout the burst. The most prominent feature was at 14.0 keV. Upon entry into the active phase the pulsar showed a significant change in pulse morphology and a likely timing glitch. The glitch had a total frequency jump of 1.9+/-0.4 x 10^-7 Hz, which recovered with a decay time of 17+/-2 days by more than the initial jump, implying a n...

  19. QPOs from Random X-ray Bursts around Rotating Black Holes

    Science.gov (United States)

    Kukumura, Keigo; Kazanas, Demosthenes; Stephenson, Gordon

    2009-01-01

    We continue our earlier studies of quasi-periodic oscillations (QPOs) in the power spectra of accreting, rapidly-rotating black holes that originate from the geometric 'light echoes' of X-ray flares occurring within the black hole ergosphere. Our present work extends our previous treatment to three-dimensional photon emission and orbits to allow for arbitrary latitudes in the positions of the distant observers and the X-ray sources in place of the mainly equatorial positions and photon orbits of the earlier consideration. Following the trajectories of a large number of photons we calculate the response functions of a given geometry and use them to produce model light curves which we subsequently analyze to compute their power spectra and autocorrelation functions. In the case of an optically-thin environment, relevant to advection-dominated accretion flows, we consistently find QPOs at frequencies of order of approximately kHz for stellar-mass black hole candidates while order of approximately mHz for typical active galactic nuclei (approximately equal to 10(exp 7) solar mass) for a wide range of viewing angles (30 degrees to 80 degrees) from X-ray sources predominantly concentrated toward the equator within the ergosphere. As in out previous treatment, here too, the QPO signal is produced by the frame-dragging of the photons by the rapidly-rotating black hole, which results in photon 'bunches' separated by constant time-lags, the result of multiple photon orbits around the hole. Our model predicts for various source/observer configurations the robust presence of a new class of QPOs, which is inevitably generic to curved spacetime structure in rotating black hole systems.

  20. NuSTAR observations of X-ray bursts from the magnetar 1E 1048.1–5937

    International Nuclear Information System (INIS)

    We report the detection of eight bright X-ray bursts from the 6.5 s magnetar 1E 1048.1–5937, during a 2013 July observation campaign with the Nuclear Spectroscopic Telescope Array. We study the morphological and spectral properties of these bursts and their evolution with time. The bursts resulted in count rate increases by orders of magnitude, sometimes limited by the detector dead time, and showed blackbody spectra with kT ∼ 6-8 keV in the T90 duration of 1-4 s, similar to earlier bursts detected from the source. We find that the spectra during the tail of the bursts can be modeled with an absorbed blackbody with temperature decreasing with flux. The burst flux decays followed a power law of index 0.8-0.9. In the burst tail spectra, we detect a ∼13 keV emission feature, similar to those reported in previous bursts from this source as well as from other magnetars observed with the Rossi X-ray Timing Explorer. We explore possible origins of the spectral feature such as proton cyclotron emission, which implies a magnetic field strength of B ∼ 2 × 1015 G in the emission region. However, the consistency of the energy of the feature in different objects requires further explanation.

  1. Development of scanning X-ray microscopes for materials science spectromicroscopy at the Advanced Light Source

    International Nuclear Information System (INIS)

    Third generation synchrotron sources of soft x-rays provide an excellent opportunity to apply established x-ray spectroscopic materials analysis techniques to surface imaging on a sub-micron scale. This paper describes an effort underway at the Advanced Light Source (ALS) to pursue this development using Fresnel zone plate lenses. These are used to produce a sub-micron spot of x-rays for use in scanning microscopy. Several groups have developed microscopes using this technique. A specimen is rastered in the focused x-ray spot and a detector signal is acquired as a function of position to generate an image. Spectroscopic capability is added by holding the small spot on a feature of interest and scanning through the spectrum. The authors are pursuing two spectroscopic techniques: Near Edge X-ray Absorption Spectroscopy (NEXAFS), X-ray Photoelectron Spectroscopy (XPS) which together provide a powerful capability for light element analysis in materials science

  2. Magnetism in the light of circular polarized x-rays

    International Nuclear Information System (INIS)

    Modern synchrotron X-ray sources providing highly intense X-rays of well-defined polarization led to the development of powerful techniques to get new insights into magnetic aspects of the electronic, crystallographic and geometric structure of solids. These methods are based on the X-ray magnetic circular dichroism (XMCD) resulting from the dependence of the X-ray absorption on the magnetization relative to the photon helicity. These effects which can be larger than 50 % occur at inner-shell absorption edges and reflect the spin and orbital polarization of the empty density of state allowing a quantitative determination of local magnetic spin and orbital moments with a high sensitivity up to 0.001 Bohr magnetons. The experimental aspects are outlined, a simple model for the origin of XMCD is presented and typical results are discussed. The unique possibility of using x-ray microscopy in combination with XMCD, which can combine lateral resolution of 15 nm and time resolution of 10 psec, is described and its potential to study magnetization dynamics in nanostructures demonstrated. (author)

  3. Tomographic analysis of the nonthermal x-ray bursts during disruption instability in the T-10 tokamak

    International Nuclear Information System (INIS)

    Non-thermal x-ray radiation (Eγ up to 150 keV) is measured in the T-10 tokamaks during disruption instability using two sets of CdTe detectors (10 vertical and 7 horizontal view detectors). Special narrow cupper tubes collimators with lead screening and CdTe detectors integrated with amplifiers inside metallic containers provides enhanced spatial resolution of the system (r ∼ 3 cm) and assures protection from the parasitic hard x-ray (Eγ up to 1.5 MeV) and electromagnetic loads during disruption. Spatial localization of the nonthermal x-ray emissivity is reconstructed using tomographic Cormack technique with SVD matrix inversion. Analysis indicated appearance of an intensive non-thermal x-ray bursts during initial stage of the disruptions at high density. The bursts are characterized by repetitive spikes (2–3 kHz) of the x-ray emissivity from the plasma core area. Analysis indicated that the spikes can be connected with acceleration of the non-thermal electrons in enhanced longitudinal electric fields induced during energy quench at the disruption instability

  4. Helium in natal HII regions: the origin of the X-ray absorption in gamma-ray burst afterglows

    CERN Document Server

    Watson, Darach; Andersen, Anja C; Fynbo, Johan P U; Gorosabel, Javier; Hjorth, Jens; Jakobsson, Páll; Krühler, Thomas; Laursen, Peter; Leloudas, Giorgos; Malesani, Daniele

    2012-01-01

    Soft X-ray absorption in excess of Galactic is observed in the afterglows of most gamma-ray bursts (GRBs), but the correct solution to its origin has not been arrived at after more than a decade of work, preventing its use as a powerful diagnostic tool. We resolve this long-standing problem and find that He in the GRB's host HII region is responsible for most of the absorption. We show that the X-ray absorbing column density (N_Hx) is correlated with both the neutral gas column density and with the optical afterglow extinction (Av). This correlation explains the connection between dark bursts and bursts with high N_Hx values. From these correlations we exclude an origin of the X-ray absorption which is not related to the host galaxy, i.e. the intergalactic medium or intervening absorbers are not responsible. We find that the correlation with the dust column has a strong redshift evolution, whereas the correlation with the neutral gas does not. From this we conclude that the column density of the X-ray absorpt...

  5. Central compact objects, superslow X-ray pulsars, gamma-ray bursts: do they have anything to do with magnetars?

    CERN Document Server

    Tong, H

    2014-01-01

    Magnetars and many of the magnetar-related objects are summarized together and discussed. It is shown that there is an abuse of language in the use of "magnetar". Anomalous X-ray pulsars and soft gamma-ray repeaters are well-known magnetar candidates. The current so called anti-magnetar (for central compact objects), accreting magnetar (for superslow X-ray pulsars in high mass X-ray binaries), and millisecond magnetar (for the central engine of some gamma-ray bursts), they may not be real magnetars in present understandings. Their observational behaviors are not caused by the magnetic energy. Many of them are just neutron stars with strong surface dipole field. A neutron star plus strong dipole field is not a magnetar. The characteristic parameters of the neutron stars for the central engine of some gamma-ray bursts are atypical from the neutron stars in the Galaxy. Possible signature of magnetic activities in accreting systems are discussed, including repeated bursts and a hard X-ray tail. China's future har...

  6. Spectroscopic comparison between ultraluminous X-ray sources and magnetar bursts

    CERN Document Server

    Kajava, J J E

    2016-01-01

    Nearby galaxies host ultra-luminous X-ray sources (ULXs), whose nature remains largely unknown. Until the discovery of the first ULX pulsar, M82 X-2, the mechanism powering the large luminosities of most ULXs was thought to be super-Eddington accretion onto black holes. The ULX pulsar clearly indicates that this hypothesis is not universal, and the question arises if other ULXs are as well powered by accretion onto neutron stars. One possibility to have highly super-Eddington luminosity is by reducing the opacity by strong magnetic fields as in magnetars, as proposed for M82 X-2. To study the link between ULXs and magnetar bursts/flares, we have performed a comparative spectral study between these classes, which both emit at similar super-Eddington luminosities at around $L \\sim 10^{40}$ erg s$^{-1}$. We find that, when their spectra are fitted with dual thermal models, the long term spectral variations of ULXs are similar to short term spectral variability seen during magnetar flares. In both classes of sour...

  7. The 2006-2007 Active Phase of Anomalous X-Ray Pulsar 4U 0142+61: Radiative and Timing Changes, Bursts,and Burst Spectral Features

    Science.gov (United States)

    Gavriil, Fotis P.; Dib, Rim; Kaspi, Victoria M.

    2011-01-01

    After at least 6 years of quiescence, Anomalous X-ray Pulsar (AXP) 4U 0142+61 entered an active phase in 2006 March that lasted several months and included six X-ray bursts as well as many changes in the persistent X-ray emission. The bursts, the first seen from this AXP in > 11 years of Rossi X-ray Timing Explorer monitoring, all occurred in the interval between 2006 April 6 and 2007 February 7. The burst durations ranged from 0.4 - 1.8 x 10(exp 3) s. The first five burst spectra are well modeled by blackbodies, with temperatures kT approx 2 - 9 keV. However, the sixth burst had a complicated spectrum that is well characterized by a blackbody plus two emission features whose amplitude varied throughout the burst. The most prominent feature was at 14.0 keV. Upon entry into the active phase the pulsar showed a significant change in pulse morphology and a likely timing glitch. The glitch had a total frequency jump of (1.9+/-0.4) x 10(exp -7) Hz, which recovered with a decay time of 17+/-2 days by more than the initial jump, implying a net spin-down of the pulsar. Within the framework of the magnetar model, the net spin-down of the star could be explained by regions of the superfluid that rotate. slower than the rest. The bursts, flux enhancements, and pulse morphology changes can be explained as arising from crustal deformations due to stresses imposed by the highly twisted internal magnetic field. However, unlike other AXP outbursts, we cannot account for a major twist being implanted in the magnetosphere.

  8. Correlation of hard X-ray and white light emission in solar flares

    OpenAIRE

    Kuhar, Matej; Krucker, Säm; Oliveros, Juan Carlos Martínez; Battaglia, Marina; Kleint, Lucia; Casadei, Diego; Hudson, Hugh S.

    2015-01-01

    A statistical study of the correlation between hard X-ray and white light emission in solar flares is performed in order to search for a link between flare-accelerated electrons and white light formation. We analyze 43 flares spanning GOES classes M and X using observations from RHESSI (Reuven Ramaty High Energy Solar Spectroscopic Imager) and HMI (Helioseismic and Magnetic Imager). We calculate X-ray fluxes at 30 keV and white light fluxes at 6173 \\r{A} summed over the hard X-ray flare ribbo...

  9. Photosphere emission in the X-ray flares of swift gamma-ray bursts and implications for the fireball properties

    International Nuclear Information System (INIS)

    X-ray flares of gamma-ray bursts (GRBs) are usually observed in the soft X-ray range and the spectral coverage is limited. In this paper, we present an analysis of 32 GRB X-ray flares that are simultaneously observed by both Burst Alert Telescope and X-Ray Telescope on board the Swift mission, so that a joint spectral analysis with a wider spectral coverage is possible. Our results show that the joint spectra of 19 flares are fitted with the absorbed single power law or the Band function models. More interestingly, the joint spectra of the other 13 X-ray flares are fitted with the absorbed single power-law model plus a blackbody component. Phenomenally, the observed spectra of these 13 flares are analogous to several GRBs with a thermal component, but only with a much lower temperature of kT = 1 ∼ 3 keV. Assuming that the thermal emission is the photosphere emission of the GRB fireball, we derive the fireball properties of the 13 flares that have redshift measurements, such as the bulk Lorentz factor Γph of the outflow. The derived Γph range from 50 to 150 and a relation of Γph to the thermal emission luminosity is found. It is consistent with the Γ0 – L iso relations that are derived for the prompt gamma-ray emission. We discuss the physical implications of these results within the content of jet composition and the radiation mechanism of GRBs and X-ray flares.

  10. DETERMINING NEUTRON STAR MASSES AND RADII USING ENERGY-RESOLVED WAVEFORMS OF X-RAY BURST OSCILLATIONS

    International Nuclear Information System (INIS)

    Simultaneous, precise measurements of the mass M and radius R of neutron stars can yield uniquely valuable information about the still uncertain properties of cold matter at several times the density of nuclear matter. One method that could be used to measure M and R is to analyze the energy-dependent waveforms of the X-ray flux oscillations seen during some thermonuclear bursts from some neutron stars. These oscillations are thought to be produced by X-ray emission from hotter regions on the surface of the star that are rotating at or near the spin frequency of the star. Here we explore how well M and R could be determined by generating and analyzing, using Bayesian techniques, synthetic energy-resolved X-ray data that we produce assuming a future space mission having 2-30 keV energy coverage and an effective area of 10 m2, such as the proposed Large Observatory for X-Ray Timing or Advanced X-Ray Timing Array missions. We find that waveforms from hot spots within 10° of the rotation equator usually constrain both M and R with an uncertainty of about 10%, if there are 106 total counts from the spot, whereas waveforms from spots within 20° of the rotation pole provide no useful constraints. The constraints we report can usually be achieved even if the burst oscillations vary with time and data from multiple bursts must be used to obtain 106 counts from the hot spot. This is therefore a promising method to constrain M and R tightly enough to discriminate strongly between competing models of cold, high-density matter

  11. Soft X-ray absorption excess in gamma-ray burst afterglow spectra: Absorption by turbulent ISM

    CERN Document Server

    Tanga, M; Gatto, A; Greiner, J; Krause, M G H; Diehl, R; Savaglio, S; Walch, S

    2016-01-01

    Two-thirds of long duration gamma-ray bursts (GRBs) show soft X-ray absorption in excess of the Milky Way. The column densities of metals inferred from UV and optical spectra differ from those derived from soft X-ray spectra, at times by an order of magnitude, with the latter being higher. The origin of the soft X-ray absorption excess observed in GRB X-ray afterglow spectra remains a heavily debated issue, which has resulted in numerous investigations on the effect of hot material both internal and external to the GRB host galaxy on our X-ray afterglow observations. Nevertheless, all models proposed so far have either only been able to account for a subset of our observations (i.e. at z > 2), or they have required fairly extreme conditions to be present within the absorbing material. In this paper, we investigate the absorption of the GRB afterglow by a collisionally ionised and turbulent interstellar medium (ISM). We find that a dense (3 per cubic centimeters) collisionally ionised ISM could produce UV/opti...

  12. INTEGRAL detects an X-ray burst from SAX J1747.0-2853 with no detectable persistent emission

    DEFF Research Database (Denmark)

    Chenevez, Jérôme; Brandt, Søren Kristian; Kuulkers, Erik;

    2009-01-01

    A new season of observations for the INTEGRAL Galactic Bulge monitoring (see ATel #438) has started on 2009 Feb. 21st. During the latest observation between 2009 Feb 25 13:21 and 17:02 (UT) a type I X-ray burst from SAX J1747.0-2853 (1A 1743-288, aka GX .2-0.2) was detected by JEM-X at UT 14:50:5...

  13. A COMPREHENSIVE ANALYSIS OF SWIFT/X-RAY TELESCOPE DATA. IV. SINGLE POWER-LAW DECAYING LIGHT CURVES VERSUS CANONICAL LIGHT CURVES AND IMPLICATIONS FOR A UNIFIED ORIGIN OF X-RAYS

    International Nuclear Information System (INIS)

    By systematically analyzing the Swift/XRT light curves detected before 2009 July, we find 19 light curves that monotonously decay as a single power law (SPL) with an index of 1 ∼ 1.7 from tens (or hundreds) of seconds to ∼105 s post the gamma-ray burst (GRB) trigger. They are apparently different from the canonical light curves characterized by a shallow-to-normal decay transition. We compare the observations of the prompt gamma rays and the X-rays for these two samples of GRBs (SPL vs. canonical). No statistical difference is found in the prompt gamma-ray properties for the two samples. The X-ray properties of the two samples are also similar, although the SPL sample tends to have a slightly lower neutral hydrogen absorption column for the host galaxies and a slightly larger energy release compared with the canonical sample. The SPL X-ray Telescope (XRT) light curves in the burst frame gradually merge into a conflux, and their luminosities at 105 s are normally distributed at log L/ergs s-1 = 45.6 ± 0.5. The normal decay segment of the canonical XRT light curves has the same feature. Similar to the normal decay segment, the SPL light curves satisfy the closure relations and therefore can be roughly explained with external shock models. In the scenario that the X-rays are the afterglows of the GRB fireball, our results indicate that the shallow decay would be due to energy injection into the fireball and the total energy budget after injection for both samples of GRBs is comparable. More intriguing, we find that a prior X-ray emission model proposed by Yamazaki is more straightforward to interpret the observed XRT data. We show that the zero times (T 0) of the X-rays are 102-105 s prior to the GRB trigger for the canonical sample, and satisfy a log-normal distribution. The negligible T 0's of the SPL sample are consistent with being the tail of T 0 distributions at low end, suggesting that the SPL sample and the canonical sample may be from a same parent

  14. Propagation of Thermonuclear Flames on Rapidly Rotating Neutron Stars: Extreme Weather during Type I X-Ray Bursts

    Science.gov (United States)

    Spitkovsky, Anatoly; Levin, Yuri; Ushomirsky, Greg

    2002-02-01

    We analyze the global hydrodynamic flow in the ocean of an accreting, rapidly rotating, nonmagnetic neutron star in a low-mass X-ray binary during a type I X-ray burst. We use both analytical arguments and numerical simulations of simplified models for ocean burning. Our analysis extends previous work by taking into account the rapid rotation of the star and the lift-up of the burning ocean during the burst. We find a new regime for the spreading of a nuclear burning front, where the flame is carried along a coherent shear flow across the front. If turbulent viscosity is weak, the speed of flame propagation is vflame~(gh)1/2/ftn~20 km s-1, where h is the scale height of the burning ocean, g is the local gravitational acceleration, tn is the timescale for fast nuclear burning during the burst, and f is the Coriolis parameter, i.e., twice the local vertical component of the spin vector. If turbulent viscosity is dynamically important, the flame speed increases and reaches the maximum value, vmaxflame~(gh/ftn)1/2~300 km s-1, when the eddy overturn frequency is comparable to the Coriolis parameter f. We show that, as a result of rotationally reduced gravity, the thermonuclear runaway which ignites the ocean is likely to begin on the equator. The equatorial belt is ignited at the beginning of the burst, and the flame then propagates from the equator to the poles. Inhomogeneous cooling (equator first, poles second) of the hot ashes drives strong zonal currents which may be unstable to the formation of Jupiter-type vortices; we conjecture that these vortices are responsible for coherent modulation of X-ray flux in the tails of some bursts. We consider the effect of strong zonal currents on the frequency of modulation of the X-ray flux and show that the large values of the frequency drifts observed in some bursts can be accounted for within our model combined with the model of homogeneous radial expansion. Additionally, if vortices or other inhomogeneities are trapped in

  15. INTEGRAL/JEM-X detection of a type-I X-ray burst from MAXI J1421-613

    DEFF Research Database (Denmark)

    Bozzo, E.; Bazzano, A.; Kuulkers, Erik;

    2014-01-01

    onset of the burst occurred on 2014 January 10 at 19:05 UTC, and the total event as observed by JEM-X lasted for about 20 s (3-25 keV). The average spectrum of the burst could be roughly described by using a black-body model with temperature kT~1 keV. The corresponding flux was 1.7E-9 erg/cm^2/s...... (translating into a luminosity of 1.3E37 erg/s at 8 kpc; 3-10 keV). We estimated a persistent flux outside the burst of 7E-10 erg/cm^2/s (3-25 keV). This detection reveals that MAXI J1421-613 is a newly discovered X-ray bursting transient source, thus hosting an accreting neutron star....

  16. Boundary conditions for the solar burst phenomenons stablished from the statistical behaviour in the hard X-ray range

    International Nuclear Information System (INIS)

    A review on the statistical studies of solar burst parameters at X-rays and microwaves, as well as an analysis of the limits caused by instrumental sensitivity and their effect on the form of the distributions and on the establishment of boundary conditions for solar flare phenomena are presented. A study on the statistical behaviour of events observed with high sensitivity at hard X-rays with the HXRBS experiment (SMM) was performed. Maxima have been formed in the parameters distribution, which may be related to intrinsic characteristics of the source-regions. This result seems to confirm searly studies which indicated the influence of the sensitivity limits. Assuming the maxima of the distributions as real, it was possible to establish boundary conditions for the mechanisms of primary energy release. The principal condition establishes that solar bursts can be interpreted as a superposition of primary explosions. The statistical analysis permitted the estimate of a value for the amount of energy in a primary explosion, making use of adjustments of Poisson functions. The value found is consistent with values derived directly from ultra-fast time structures observed in bursts. Assuming an empirical pulse shape for the primary burst and the superposition condition, simulations of bursts have been successfully obtained. (Author)

  17. Bursting SN 1996cr's Bubble: Hydrodynamic and X-ray Modeling of its Circumstellar Medium

    CERN Document Server

    Dwarkadas, Vikram V; Bauer, Franz

    2010-01-01

    SN1996cr is one of the five closest SNe to explode in the past 30 years. Due to its fortuitous location in the Circinus Galaxy at ~ 3.7 Mpc, there is a wealth of recently acquired and serendipitous archival data available to piece together its evolution over the past decade, including a recent 485 ks Chandra HETG spectrum. In order to interpret this data, we have explored hydrodynamic simulations, followed by computations of simulated spectra and light curves under non-equilibrium ionization conditions, and directly compared them to the observations. Our simulated spectra manage to fit both the X-ray continuum and lines at 4 epochs satisfactorily, while our computed light curves are in good agreement with additional flux-monitoring data sets. These calculations allow us to infer the nature and structure of the circumstellar medium, the evolution of the SN shock wave, and the abundances of the ejecta and surrounding medium. The data imply that SN 1996cr exploded in a low-density medium before interacting with ...

  18. New Directions in X-Ray Light Sources or Fiat Lux: what's under the dome and watching atoms with x-rays (LBNL Summer Lecture Series)

    International Nuclear Information System (INIS)

    Summer Lecture Series 2008: Molecular movies of chemical reactions and material phase transformations need a strobe of x-rays, the penetrating light that reveals how atoms and molecules assemble in chemical and biological systems and complex materials. Roger Falcone, Director of the Advanced Light Source, will discuss a new generation of x-ray sources that will enable a new science of atomic dynamics on ultrafast timescales.

  19. The Soft X-ray Research instrument at the Linac Coherent Light Source

    International Nuclear Information System (INIS)

    A description of the Soft X-ray Research instrument (SXR) at the Linac Coherent Light Source is given. Recent scientific highlights illustrate the wide variety of experiments and detectors that can be accommodated at SXR. The Soft X-ray Research instrument provides intense ultrashort X-ray pulses in the energy range 280–2000 eV. A diverse set of experimental stations may be installed to investigate a broad range of scientific topics such as ultrafast chemistry, highly correlated materials, magnetism, surface science, and matter under extreme conditions. A brief description of the main instrument components will be given, followed by some selected scientific highlights

  20. Absolute Pulse Energy Measurements of Soft X-Rays at the Linac Coherent Light Source

    OpenAIRE

    Tiedtke, K.; Sorokin, Andrey; Soufli, R.; Fernández-Perea, M.; Juha, L.; Heimann, P.(Universität Siegen, Siegen, Germany); Nagler, B.; Lee, H. J.; Mack, S; Cammarata, M.; O. Krupin; Messerschmidt, M.; Jastrow, U.; Holmes, M.; Rowen, M.

    2014-01-01

    This paper reports novel measurements of x-ray optical radiation on an absolute scale from the intense and ultra-short radiation generated in the soft x-ray regime of a free electron laser. We give a brief description of the detection principle for radiation measurements which was specifically adapted for this photon energy range. We present data characterizing the soft x-ray instrument at the Linac Coherent Light Source (LCLS) with respect to the radiant power output and transmission by usin...

  1. The Coherent X-ray Imaging instrument at the Linac Coherent Light Source

    International Nuclear Information System (INIS)

    Description of the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source. Recent scientific highlights illustrate the femtosecond crystallography, high power density and extreme matter capabilities of the CXI instrument. The Coherent X-ray Imaging (CXI) instrument specializes in hard X-ray, in-vacuum, high power density experiments in all areas of science. Two main sample chambers, one containing a 100 nm focus and one a 1 µm focus, are available, each with multiple diagnostics, sample injection, pump–probe and detector capabilities. The flexibility of CXI has enabled it to host a diverse range of experiments, from biological to extreme matter

  2. The Coherent X-ray Imaging instrument at the Linac Coherent Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Mengning; Williams, Garth J.; Messerschmidt, Marc; Seibert, M. Marvin; Montanez, Paul A.; Hayes, Matt; Milathianaki, Despina; Aquila, Andrew; Hunter, Mark S.; Koglin, Jason E.; Schafer, Donald W.; Guillet, Serge; Busse, Armin; Bergan, Robert; Olson, William; Fox, Kay; Stewart, Nathaniel; Curtis, Robin; Miahnahri, Alireza Alan; Boutet, Sébastien, E-mail: sboutet@slac.stanford.edu [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2015-04-15

    Description of the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source. Recent scientific highlights illustrate the femtosecond crystallography, high power density and extreme matter capabilities of the CXI instrument. The Coherent X-ray Imaging (CXI) instrument specializes in hard X-ray, in-vacuum, high power density experiments in all areas of science. Two main sample chambers, one containing a 100 nm focus and one a 1 µm focus, are available, each with multiple diagnostics, sample injection, pump–probe and detector capabilities. The flexibility of CXI has enabled it to host a diverse range of experiments, from biological to extreme matter.

  3. Resonant Soft X-ray Spectroscopic Studies of Light Actinides and Copper Systems

    OpenAIRE

    Modin, Anders

    2009-01-01

    Light actinides and copper systems were studied using resonant soft X-ray spectroscopy. An instrumental and experimental setup for soft X-ray spectroscopy meeting the requirements of a closed source for radioactivity was developed and described in detail. The setup was used for studies of single-crystal PuO2 oxidation. The existence of higher oxidation state than Pu(IV) in some surface areas of the single crystal were found from O 1s X-ray absorption measurements. Furthermore, from comparison...

  4. X-ray holographic microscopy experiments at the Brookhaven synchrotron light source

    International Nuclear Information System (INIS)

    Soft x-ray holographic microscopy is discussed from an experimental point of view. Three series of measurements have been carried out using the Brookhaven 750 MeV storage ring as an x-ray source. Young slits fringes, Gabor (in line) holograms and various data pertaining to the soft x-ray performance of photographic plates are reported. The measurements are discussed in terms of the technique for recording them and the experimental limitations in effect. Some discussion is also given of the issues involved in reconstruction using visible light

  5. X-ray holographic microscopy experiments at the Brookhaven Synchrotron Light Source

    International Nuclear Information System (INIS)

    Soft X-ray holographic microscopy is discussed from an experimental point of view. Three series of measurements have been carried out using the Brookhaven 750 MeV storage ring as an X-ray source. Young slits fringes, Gabor (in line) holograms and various data pertaining to the soft x-ray performance of photographic plates are reported. The measurements are discussed in terms of the technique for recording them and the experimental limitations in effect. Some discussion is also given of the issues involved in reconstruction using visible light

  6. A preliminary study of synchrotron light sources for x-ray lithography

    International Nuclear Information System (INIS)

    A preliminary study of synchrotron light sources has been made, primarily oriented toward x-ray lithography. X-ray lithography is being pursued vigorously in several countries, with a goal of manufacturing high-density computer chips (0.25 μm feature sizes), and may attain commercial success in the next decade. Many other applications of soft x-rays appear worthy of investigation as well. The study group visited synchrotron radiation facilities and had discussions with members of the synchrotron radiation community, particularly Canadians. It concluded that accelerator technology for a conventional synchrotron light source appropriate for x-ray lithography is well established and is consistent with skills and experience at Chalk River Nuclear Laboratories. Compact superconducting systems are being developed also. Their technical requirements overlap with capabilities at Chalk River. (32 refs)

  7. LFN, QPO and fractal dimension of X-ray light curves from black hole binaries

    Science.gov (United States)

    Prosvetov, Art; Grebenev, Sergey

    The origin of the low frequency noise (LFN) and quasi-periodic oscillations (QPO) observed in X-ray flux of Galactic black hole binaries is still not recognized in spite of multiple studies and attempts to model this phenomenon. There are known correlations between the QPO frequency, X-ray power density, X-ray flux and spectral state of the system, but there is no model that can do these dependences understandable. For the low frequency (~1 Hz) QPO we still have no even an idea capable to explain their production and don't know even what part of an accretion disc is responsible for them. Here we attempted to measure the fractal dimension of X-ray light curves of several black hole X-ray binaries and to study its correlation with the frequency of quasi periodic oscillations observed in their X-ray light-curves. The fractal dimension is a measure of the space-filling capacity of the light curves' profile. To measure the fractal dimension we used R/S method, which is fast enough and has good reputation in financial analytic and materials sciences. We found that if no QPO were observed in X-ray flux from the particular source, the fractal dimension is equal to the unique value which is independent on the source, its luminosity or its spectral state. On the other hand if QPO were detected in the flux, the fractal dimension deviated from its usual value. Also, we found a clear correlation between the QPO frequency and the fractal dimension of the emission. The relationship between these two parameters is solid but nonlinear. We believe that the analysis of X-ray light curves of black hole binaries using the fractal dimension has a good scientific potential and may provide an addition information on the geometry of accretion flow and fundamental physical parameters of the system.

  8. LIGHT SOURCE: TW Laser system for Thomson scattering X-ray light source at Tsinghua University

    Science.gov (United States)

    Yan, Li-Xm; Du, Ying-Chao; Du, Qiang; Li, Ren-Kai; Hua, Jian-Fei; Huang, Wen-Hui; Tang, Chuan-Xiang

    2009-06-01

    A TW (Tera Watt) laser system based on Ti:sapphire mainly for the Tsinghua Thomson scattering X-ray light source (TTX) is being built. Both UV (ultraviolet) laser pulse for driving the photocathode radio-frequency (RF) gun and the IR (infrared) laser pulse as the electron-beam-scattered-light are provided by the system. Efforts have also been made in laser pulse shaping and laser beam transport to optimize the high-brightness electron beam production by the photocathode RF gun.

  9. THE XMM-NEWTON/EPIC X-RAY LIGHT CURVE ANALYSIS OF WR 6

    International Nuclear Information System (INIS)

    We obtained four pointings of over 100 ks each of the well-studied Wolf-Rayet star WR 6 with the XMM-Newton satellite. With a first paper emphasizing the results of spectral analysis, this follow-up highlights the X-ray variability clearly detected in all four pointings. However, phased light curves fail to confirm obvious cyclic behavior on the well-established 3.766 day period widely found at longer wavelengths. The data are of such quality that we were able to conduct a search for event clustering in the arrival times of X-ray photons. However, we fail to detect any such clustering. One possibility is that X-rays are generated in a stationary shock structure. In this context we favor a corotating interaction region (CIR) and present a phenomenological model for X-rays from a CIR structure. We show that a CIR has the potential to account simultaneously for the X-ray variability and constraints provided by the spectral analysis. Ultimately, the viability of the CIR model will require both intermittent long-term X-ray monitoring of WR 6 and better physical models of CIR X-ray production at large radii in stellar winds

  10. X-ray Flashes or soft Gamma-ray Bursts? The case of the likely distant XRF 040912

    CERN Document Server

    Stratta, G; Butler, N; Atteia, J L; Gendre, B; Pelangeon, A; Malacrino, F; Mellier, Y; Kann, D A; Klose, S; Zeh, A; Masetti, N; Palazzi, E; Gorosabel, J; Castro-Tirado, A J; De Postigo, A U; Jelinek, M; Cepa, J; Castaneda, H; Martínez-Delgado, D; Boër, M; Braga, J; Crew, G; Donaghy, T Q; Dezalay, J P; Doty, J; Fenimore, E E; Galassi, M; Graziani, C; Jernigan, J G; Kawai, N; Lamb, D Q; Levine, A; Manchanda, J; Martel, F; Matsuoka, M; Nakagawa, Y; Olive, J F; Pizzichini, G; Prigozhin, G Y; Ricker, G; Sakamoto, T; Shirasaki, Y; Sugita, S; Suzuki, M; Takagishi, K; Tamagawa, T; Vanderspek, R; Villasenor, J; Woosley, S E; Yamauchi, M; Yoshida, A

    2006-01-01

    In this work, we present a multi-wavelength study of XRF 040912, aimed at measuring its distance scale and the intrinsic burst properties. We performed a detailed spectral and temporal analysis of both the prompt and the afterglow emission and we estimated the distance scale of the likely host galaxy. We then used the currently available sample of XRFs with known distance to discuss the connection between XRFs and classical Gamma-ray Bursts (GRBs). We found that the prompt emission properties unambiguously identify this burst as an XRF, with an observed peak energy of E_p=17+/-13 keV and a burst fluence ratio S(2-30keV)/S(30-400keV)>1. A non-fading optical source with R~24 mag and with an apparently extended morphology is spatially consistent with the X-ray afterglow, likely the host galaxy. XRF 040912 is a very dark burst since no afterglow optical counterpart is detected down to R>25 mag (3 sigma limiting magnitude) at 13.6 hours after the burst. The host galaxy spectrum detected from 3800A to 10000A, shows...

  11. The soft x-ray instrument for materials studies at the linac coherent light source x-ray free-electron laser

    OpenAIRE

    Schlotter, W. F.; Turner, J. J.; Fernández-Perea, M.; Kelez, N.; Lee, S.; Coffee, R.; Hays, G.; Beye, M; Gerken, N.; Sorgenfrei, F.; Hau-Riege, S.; Juha, L.; Rowen, M; Chalupsky, J.; Hajkova, V

    2012-01-01

    The soft x-ray materials science instrument is the second operational beamline at the linac coherent light source x-ray free electron laser. The instrument operates with a photon energy range of 480-2000 eV and features a grating monochromator as well as bendable refocusing mirrors. A broad range of experimental stations may be installed to study diverse scientific topics such as: ultrafast chemistry, surface science, highly correlated electron systems, matter under extreme conditions, and la...

  12. The time ending the shallow decay of the X-ray light curves of long GRBs

    CERN Document Server

    Nava, L; Ghirlanda, G; Cabrera, J I; Firmani, C; Avila-Reese, V

    2007-01-01

    The early X-ray light curve of Gamma Ray Bursts (GRBs) is complex, and shows a typical steep-flat-steep behaviour. The time T_a at which the flat (plateau) part ends may bear some important physical information, especially if it plays the same role of the so called jet break time t_jet. To this aim, stimulated by the recent analysis of Willingale et al., we have assembled a sample of GRBs of known redshifts, spectral parameters of the prompt emission, and T_a. By using T_a as a jet angle indicator, and then estimating the collimation corrected prompt energetics, we find a correlation between the latter quantity and the peak energy of the prompt emission. However, this correlation has a large dispersion, similar to the dispersion of the Amati correlation and it is not parallel to the Ghirlanda correlation. Furthermore, we show that the correlation itself results mainly from the dependence of the jet opening angle on the isotropic prompt energy, with the time T_a playing no role, contrary to what we find for th...

  13. Can X-ray emission powered by a spinning-down magnetar explain some GRB light curve features?

    CERN Document Server

    Lyons, N; Zhang, B; Willingale, R; Troja, E; Starling, R L C

    2009-01-01

    Long duration gamma-ray bursts (GRBs) are thought to be produced by the core-collapse of a rapidly-rotating massive star. This event generates a highly relativistic jet and prompt gamma-ray and X-ray emission arises from internal shocks in the jet or magnetised outflows. If the stellar core does not immediately collapse to a black hole, it may form an unstable, highly magnetised millisecond pulsar, or magnetar. As it spins down, the magnetar would inject energy into the jet causing a distinctive bump in the GRB light curve where the emission becomes fairly constant followed by a steep decay when the magnetar collapses. We assume that the collapse of a massive star to a magnetar can launch the initial jet. By automatically fitting the X-ray lightcurves of all GRBs observed by the Swift satellite we identified a subset of bursts which have a feature in their light curves which we call an internal plateau -- unusually constant emission followed by a steep decay -- which may be powered by a magnetar. We use the d...

  14. The X-ray Pump–Probe instrument at the Linac Coherent Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Chollet, Matthieu; Alonso-Mori, Roberto; Cammarata, Marco; Damiani, Daniel; Defever, Jim; Delor, James T.; Feng, Yiping; Glownia, James M.; Langton, J. Brian; Nelson, Silke; Ramsey, Kelley; Robert, Aymeric; Sikorski, Marcin; Song, Sanghoon; Stefanescu, Daniel; Srinivasan, Venkat; Zhu, Diling, E-mail: dlzhu@slac.stanford.edu [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Lemke, Henrik T. [Paul Scherrer Institut, CH-5232 Villigen (Switzerland); Fritz, David M. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2015-04-21

    A description of the X-ray Pump–Probe (XPP) instrument at the Linac Coherent Light Source. is presented. Recent scientific highlights illustrate the versatility and the time-resolved X-ray diffraction and spectroscopy capabilities of the XPP instrument. The X-ray Pump–Probe instrument achieves femtosecond time-resolution with hard X-ray methods using a free-electron laser source. It covers a photon energy range of 4–24 keV. A femtosecond optical laser system is available across a broad spectrum of wavelengths for generating transient states of matter. The instrument is designed to emphasize versatility and the scientific goals encompass ultrafast physical, chemical and biological processes involved in the transformation of matter and transfer of energy at the atomic scale.

  15. Correlation of hard X-ray and white light emission in solar flares

    CERN Document Server

    Kuhar, Matej; Oliveros, Juan Carlos Martínez; Battaglia, Marina; Kleint, Lucia; Casadei, Diego; Hudson, Hugh S

    2015-01-01

    A statistical study of the correlation between hard X-ray and white light emission in solar flares is performed in order to search for a link between flare-accelerated electrons and white light formation. We analyze 43 flares spanning GOES classes M and X using observations from RHESSI (Reuven Ramaty High Energy Solar Spectroscopic Imager) and HMI (Helioseismic and Magnetic Imager). We calculate X-ray fluxes at 30 keV and white light fluxes at 6173 \\r{A} summed over the hard X-ray flare ribbons with an integration time of 45 seconds around the peak hard-X ray time. We find a good correlation between hard X-ray fluxes and excess white light fluxes, with a highest correlation coefficient of 0.68 for photons with energy of 30 keV. Assuming the thick target model, a similar correlation is found between the deposited power by flare-accelerated electrons and the white light fluxes. The correlation coefficient is found to be largest for energy deposition by electrons above ~50 keV. At higher electron energies the co...

  16. Single crystal scintillator plates used for light weight material X-ray radiography

    Science.gov (United States)

    Tous, J.; Blazek, K.; Nikl, M.; Mares, J. A.

    2013-03-01

    Very thin scintillator imaging plates have recently become of great interest. In high resolution X-ray projection imaging, very thin scintillators of about 5-20 micrometres are used to achieve high spatial resolution. Such thin screens are mainly used in micro-CT and nano-CT systems with either micro-focus X-ray tubes or with synchrotron sources. This work deals with a high resolution CCD camera in connection with an optical system and different single crystal scintillators in application for low energy X-ray micro-radiography. The thin screens used were prepared by mechanical polishing from Y3Al5O12 or Lu3Al5O12 single crystals. The screens can be used in equipment for the detection of different kinds of radiation and particles (UV, VUV, electrons or ions or their beams, X- or gamma-rays). A high resolution open type micro-focus X-ray tube was used to achieve the high resolution. The results show that the single crystal plates exhibit high spatial resolution and high sensitivity to low energy X-rays resulting in high image contrast. The use of the plates is highly suitable for light weight (low Z) material X-ray radiography. The resolution achieved is demonstrated using a test grid. Several light weight objects are imaged using the thin plates.

  17. Single crystal scintillator plates used for light weight material X-ray radiography

    International Nuclear Information System (INIS)

    Very thin scintillator imaging plates have recently become of great interest. In high resolution X-ray projection imaging, very thin scintillators of about 5-20 micrometres are used to achieve high spatial resolution. Such thin screens are mainly used in micro-CT and nano-CT systems with either micro-focus X-ray tubes or with synchrotron sources. This work deals with a high resolution CCD camera in connection with an optical system and different single crystal scintillators in application for low energy X-ray micro-radiography. The thin screens used were prepared by mechanical polishing from Y3Al5O12 or Lu3Al5O12 single crystals. The screens can be used in equipment for the detection of different kinds of radiation and particles (UV, VUV, electrons or ions or their beams, X- or gamma-rays). A high resolution open type micro-focus X-ray tube was used to achieve the high resolution. The results show that the single crystal plates exhibit high spatial resolution and high sensitivity to low energy X-rays resulting in high image contrast. The use of the plates is highly suitable for light weight (low Z) material X-ray radiography. The resolution achieved is demonstrated using a test grid. Several light weight objects are imaged using the thin plates.

  18. Microwave and X-Ray emission during a isentropic expansion and its application to solar bursts

    International Nuclear Information System (INIS)

    The gyro-synchrotron emission in microwaves and the free-free emission in X-rays of a plasma enclosed in a cylinder coincident with a magnetic force tube were calculated for an isentropic self-similar expansion, with plane and cylindrical symmetries. This expansion model was applied to a region of the low solar corona, and the results were compared to the emission observed in some simple solar events of low intensity. The calculations show satisfactory coincidence with the events in X-rays for energies around 1029 ergs. The solar events analyzed in microwaves, which are not the same that were studied in X-rays, in general do not fit the theoretical results. The origin of the discrepancy is probably the formulation of the processes of emission applied to the expansion. (Author)

  19. Failed Gamma-Ray Bursts: Thermal UV/Soft X-ray Emission Accompanied by Peculiar Afterglows

    CERN Document Server

    Xu, M; Huang, Y -F; Lee, S -H

    2011-01-01

    We show that the photospheres of "failed" Gamma-Ray Bursts (GRBs), whose bulk Lorentz factors are much lower than 100, can be outside of internal shocks. The resulting radiation from the photospheres is thermal and bright in UV/Soft X-ray band. The photospheric emission lasts for about one thousand seconds with luminosity about several times 10^46 erg/s. These events can be observed by current and future satellites. It is also shown that the afterglows of failed GRBs are peculiar at the early stage, which makes it possible to distinguish failed GRBs from ordinary GRBs and beaming-induced orphan afterglows.

  20. Interpretation of the burst spectra from X-ray burster MXB 1728-34 with allowance for Thomson scattering

    International Nuclear Information System (INIS)

    Spectral evolution is investigated and interpretations of the spectra are considered for a burst from the X-ray burster MXB 1728-34 detected by ASTRON. Interpretation of the burst spectra in terms of black.body radiation leads to improbably small neutron star (NS) mass M and radius R as well as distance D to the burster. Interpretation of the spectra around the burst maximum (first ≅4 s) in terms of radiation from an isothermal NS photosphere with dominating role of the Thomson scattering allows one to obtain reasonable constraints on M, R, and D (in particular, M=(1.4-2) M Sun, R=(6.5-12) km for D=6 kpk and helium photosphere). This interpretation leads to a conclusion that the photosphere expands up to several tens of kilometers in the burst maximum. The luminosity remains close to the Eddington limit during expansion and contraction; maxima of the observed flux corresponding to minima of the luminosity due to general relativity effects. The burst tail spectra are close to those of thermal bremstrahlung. Such spectra might originate in a corona around NS with mass ∼ 10 -16 MSun, radius ∼ 100 km and electron density ∼ 1019 cm-3, or in a hot layer with thickness ∼ 1-10 gxcm-2 on the photosphere

  1. X-ray micro-Tomography at the Advanced Light Source

    Science.gov (United States)

    The X-ray micro-Tomography Facility at the Advanced Light Source has been in operation since 2004. The source is a superconducting bend magnet of critical energy 10.5KeV; photon energy coverage is 8-45 KeV in monochromatic mode, and a filtered white light option yields useful photons up to 50 KeV. A...

  2. Constraints on the inner accretion flow of 4U/MXB 1636-53 (V 801 Arae) from a comparison of X-ray burst and persistent emission

    NARCIS (Netherlands)

    E. Damen; R.A.M.J. Wijers; J. van Paradijs; W. Penninx; T. Oosterbroek; W.H.G. Lewin; F. Jansen

    1990-01-01

    A detailed analysis is presented of the importance of Comptonization in burst and persistent spectra of the low-mass X-ray binary 4U/MXB 1636-53, and from this analysis it is inferred that the inner accretion flow is geometrically thin. It is found that burst spectra of 1636-53 are very nearly Planc

  3. The Definitive X-ray Light Curve of Swift J164449.3+573451

    CERN Document Server

    Mangano, V; Sbarufatti, B; Cannizzo, J K

    2015-01-01

    On March 28, 2011, the Swift Burst Alert Telescope triggered on an object that had no analog in over six years of Swift operations. Follow-up observations by the Swift X-ray Telescope (XRT) found a new, bright X-ray source covering 3 orders of magnitude in flux over the first few days, that was much more persistent (and variable) than gamma-ray burst afterglows. Ground-based spectroscopy found a redshift of 0.35, implying extremely high luminosity, with integrated isotropic-equivalent energy output in the X-ray band alone exceeding $10^{53}$ ergs in the first two weeks after discovery. Strong evidence for a collimated outflow or beamed emission was found. The observational properties of this object are unlike anything ever before observed. We interpret these unique properties as the result of emission from a relativistic jet produced in the aftermath of the tidal disruption of a main sequence star by a massive black hole (BH) in the center of the host galaxy. The source decayed slowly as the stellar remnants ...

  4. The Swift Burst Alert Telescope Detected Seyfert 1 Galaxies: X-Ray Broadband Properties and Warm Absorbers

    Science.gov (United States)

    Winter, Lisa M.; Veilleux, Sylvain; McKernan, Barry; Kallman, T.

    2012-01-01

    We present results from an analysis of the broadband, 0.3-195 keV, X-ray spectra of 48 Seyfert 1-1.5 sources detected in the very hard X-rays with the Swift Burst Alert Telescope (BAT). This sample is selected in an all-sky survey conducted in the 14-195 keV band. Therefore, our sources are largely unbiased toward both obscuration and host galaxy properties. Our detailed and uniform model fits to Suzaku/BAT and XMM-Newton/BAT spectra include the neutral absorption, direct power-law, reflected emission, soft excess, warm absorption, and narrow Fe I K[alpha] emission properties for the entire sample. We significantly detect O VII and O VIII edges in 52% of our sample. The strength of these detections is strongly correlated with the neutral column density measured in the spectrum. Among the strongest detections, X-ray grating and UV observations, where available, indicate outflowing material. The ionized column densities of sources with O VII and O VIII detections are clustered in a narrow range with Nwarm [approx] 1021 cm-2, while sources without strong detections have column densities of ionized gas an order of magnitude lower. Therefore, we note that sources without strong detections likely have warm ionized outflows present but at low column densities that are not easily probed with current X-ray observations. Sources with strong complex absorption have a strong soft excess, which may or may not be due to difficulties in modeling the complex spectra of these sources. Still, the detection of a flat [Gamma] [approx] 1 and a strong soft excess may allow us to infer the presence of strong absorption in low signal-to-noise active galactic nucleus spectra. Additionally, we include a useful correction from the Swift BAT luminosity to bolometric luminosity, based on a comparison of our spectral fitting results with published spectral energy distribution fits from 33 of our sources.

  5. Solving X-ray protein structures without a crystal: using X-ray Free Electron Laser, the fourth generation synchrotron light sources

    Institute of Scientific and Technical Information of China (English)

    Bo Huang

    2010-01-01

    @@ A synchrotron light source is a source of electromagnetic radiation artificially produced by specialized electron accelerators. Compared to the commonly used in-house X-ray sources, it is wavelength adjustable, much stronger and more focused. In the last two decades, synchrotron usage has become the mainstream for X-ray protein structure determination. Taking the advantage of micro-focus light beams of the third generation synchrotron, the size of a usable protein crystal for data collection decreases to micron level, which increases the rate of macromolecular structure determination to about 10 new protein data bank entries per day.

  6. Burst Tails from SGR J1550-5418 Observed with Rossi X-ray Timing Explorer

    CERN Document Server

    Mus, Sinem Sasmaz; Kaneko, Yuki; Chakraborty, Manoneeta; Aydin, Berk

    2015-01-01

    We present the results of our extensive search using the Bayesian block method for long tails following short bursts from a magnetar, SGR J1550-5418, over all RXTE observations of the source. We identified four bursts with extended tails, most of which occurred during its 2009 burst active episode. The durations of tails range between ~13 s and over 3 ks, which are much longer than the typical duration of bursts. We performed detailed spectral and temporal analysis of the burst tails. We find that the spectra of three tails show a thermal nature with a trend of cooling throughout the tail. We compare the results of our investigations with the properties of four other extended tails detected from SGR 1900+14 and SGR 1806-20 and suggest a scenario for the origin of the tail in the framework of the magnetar model.

  7. Hard X-ray bursts and DD microfusion neutrons from complex plasmas of vacuum discharge

    Indian Academy of Sciences (India)

    Yu K Kurilenkov; M Skowronek

    2003-12-01

    We create the random complex media of high-power density in low-energy nanosecond vacuum discharges. Hard X-ray emission efficiency, generation of energetic ions (∼ 1 MeV) and neutrons, trapping and releasing of fast ions and/or X-rays from interelectrode aerosol ensembles are the subject of our study. The neutrons from DD microfusion, as well as the modelling of some interstellar nuclear burning due to microexplosive nucleosynthesis are discussed. The value of neutron yield from DD fusion in interelectrode space varies and amounts to ∼ 105-107/4 per shot under ≈ 1 J of total energy deposited to create all discharge processes.

  8. Temporal behaviour of the thermal model of hard X-ray bursts

    Science.gov (United States)

    Mackinnon, A. L.

    1985-01-01

    A simple, analytic model is presented of a hot, thermal hard X-ray source, continuously heated, bounded by ion-acoustic conduction fronts, and expanding in a loop. The model is used to investigate the assumption that the 'rise time' of the X-ray emission is approximately given by the loop length divided by the ion-sound speed appropriate to the peak temperature. It is found that a freely-expanding source does not behave in this way; instead, the rise time is symptomatic of the timescale for primary energy release. If the energy release rate does not fall significantly before the source fills the loop, however, then this assumption may be approximately satisfied, if a condition on the temporal behavior of the energy release is satisfied. Finally, some remarks on the relative timing of temperature and emission measure peaks are made, and possible further applications mentioned of the results presented herein.

  9. Gamma-Ray Burst long lasting X-ray flaring activity

    CERN Document Server

    Bernardini, M G; Chincarini, G; Guidorzi, C; Mao, J; Pasotti, F

    2010-01-01

    We complete the flare observational picture analysing the late time (i.e. t_{pk} >~ 1000 s) flares observed by Swift in the 0.3-10 keV energy band. The aim is to extend the knowledge of the temporal and energetic properties of X-ray flares up to 3 orders of magnitude in time in order to identify possible differences in the mechanism producing the early and late time flaring emission, if any. This requires the complete understanding of the observational biases affecting the detection of X-ray flares superimposed on a fading continuum at t > 1000 s. We find that the width of flares increases with time up to 10^6 s, and the linear relation between decay time and rise time still holds for late time flares. Late time flares are less energetic than early time flares by at least 1 order of magnitude, and they are also dimmer, being the peak luminosity anticorrelated with the peak time. Whatever produces each X-ray flare keeps memory of the previous GRB history, starting from the prompt emission, and it has to be cap...

  10. Burst and Persistent Emission Properties during the Recent Active Episode of the Anomalous X-Ray Pulsar 1E 1841-045

    Science.gov (United States)

    Lin, Lin; Kouveliotou, Chryssa; Gogus, Ersin; van der Horst, Alexander J.; Watts, Anna L.; Baring, Matthew G.; Kaneko, Yuki; Wijers, Ralph A. M. J.; Woods, Peter M.; Barthelmy, Scott; Burgess, J. Michael; Chaplin, Vandiver; Gehrels, Neil; Goldstein, Adam; Granot, Jonathan; Guiriec, Sylvain; Mcenery, Julie; Preece, Robert D.; Tierney, David; van der Klis, Michiel; von Kienlin, Andreas; Zhang, Shuang Nan

    2011-01-01

    SWift/BAT detected the first burst from 1E 1841-045 in May 2010 with intermittent burst activity recorded through at least July 2011. Here we present Swift and Fermi/GBM observations of this burst activity and search for correlated changes to the persistent X-ray emission of the source. The T90 durations of the bursts range between 18 - 140 ms, comparable to other magnetar burst durations, while the energy released in each burst ranges between (0.8-25) x 1038 erg, which is in the low side of SGR bursts. We find that the bursting activity did not have a significant effect on the persistent flux level of the source. We argue that the mechanism leading to this sporadic burst activity in IE 1841-045 might not involve large scale restructuring (either crustal or magnetospheric) as seen in other magnetar sources.

  11. THE HARD X-RAY SPECTRUM OF NGC 1365: SCATTERED LIGHT, NOT BLACK HOLE SPIN

    Energy Technology Data Exchange (ETDEWEB)

    Miller, L. [Department of Physics, Oxford University, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Turner, T. J. [Department of Physics, University of Maryland Baltimore County, Baltimore, MD 21250 (United States)

    2013-08-10

    Active galactic nuclei (AGNs) show excess X-ray emission above 10 keV compared with extrapolation of spectra from lower energies. Risaliti et al. have recently attempted to model the hard X-ray excess in the type 1.8 AGN NGC 1365, concluding that the hard excess most likely arises from Compton-scattered reflection of X-rays from an inner accretion disk close to the black hole. Their analysis disfavored a model in which the hard excess arises from a high column density of circumnuclear gas partially covering a primary X-ray source, despite such components being required in the NGC 1365 data below 10 keV. Using a Monte Carlo radiative transfer approach, we demonstrate that this conclusion is invalidated by (1) use of slab absorption models, which have unrealistic transmission spectra for partial covering gas, (2) neglect of the effect of Compton scattering on transmitted spectra, and (3) inadequate modeling of the spectrum of scattered X-rays. The scattered spectrum is geometry-dependent and, for high global covering factors, may dominate above 10 keV. We further show that, in models of circumnuclear gas, the suppression of the observed hard X-ray flux by reprocessing may be no larger than required by the ''light bending'' model invoked for inner disk reflection, and the expected emission line strengths lie within the observed range. We conclude that the time-invariant ''red wing'' in AGN X-ray spectra is probably caused by continuum transmitted through and scattered from circumnuclear gas, not by highly redshifted line emission, and that measurement of black hole spin is not possible.

  12. THE HARD X-RAY SPECTRUM OF NGC 1365: SCATTERED LIGHT, NOT BLACK HOLE SPIN

    International Nuclear Information System (INIS)

    Active galactic nuclei (AGNs) show excess X-ray emission above 10 keV compared with extrapolation of spectra from lower energies. Risaliti et al. have recently attempted to model the hard X-ray excess in the type 1.8 AGN NGC 1365, concluding that the hard excess most likely arises from Compton-scattered reflection of X-rays from an inner accretion disk close to the black hole. Their analysis disfavored a model in which the hard excess arises from a high column density of circumnuclear gas partially covering a primary X-ray source, despite such components being required in the NGC 1365 data below 10 keV. Using a Monte Carlo radiative transfer approach, we demonstrate that this conclusion is invalidated by (1) use of slab absorption models, which have unrealistic transmission spectra for partial covering gas, (2) neglect of the effect of Compton scattering on transmitted spectra, and (3) inadequate modeling of the spectrum of scattered X-rays. The scattered spectrum is geometry-dependent and, for high global covering factors, may dominate above 10 keV. We further show that, in models of circumnuclear gas, the suppression of the observed hard X-ray flux by reprocessing may be no larger than required by the ''light bending'' model invoked for inner disk reflection, and the expected emission line strengths lie within the observed range. We conclude that the time-invariant ''red wing'' in AGN X-ray spectra is probably caused by continuum transmitted through and scattered from circumnuclear gas, not by highly redshifted line emission, and that measurement of black hole spin is not possible

  13. The Hard X-Ray Spectrum of NGC 1365: Scattered Light, Not Black Hole Spin

    Science.gov (United States)

    Miller, L.; Turner, T. J.

    2013-08-01

    Active galactic nuclei (AGNs) show excess X-ray emission above 10 keV compared with extrapolation of spectra from lower energies. Risaliti et al. have recently attempted to model the hard X-ray excess in the type 1.8 AGN NGC 1365, concluding that the hard excess most likely arises from Compton-scattered reflection of X-rays from an inner accretion disk close to the black hole. Their analysis disfavored a model in which the hard excess arises from a high column density of circumnuclear gas partially covering a primary X-ray source, despite such components being required in the NGC 1365 data below 10 keV. Using a Monte Carlo radiative transfer approach, we demonstrate that this conclusion is invalidated by (1) use of slab absorption models, which have unrealistic transmission spectra for partial covering gas, (2) neglect of the effect of Compton scattering on transmitted spectra, and (3) inadequate modeling of the spectrum of scattered X-rays. The scattered spectrum is geometry-dependent and, for high global covering factors, may dominate above 10 keV. We further show that, in models of circumnuclear gas, the suppression of the observed hard X-ray flux by reprocessing may be no larger than required by the "light bending" model invoked for inner disk reflection, and the expected emission line strengths lie within the observed range. We conclude that the time-invariant "red wing" in AGN X-ray spectra is probably caused by continuum transmitted through and scattered from circumnuclear gas, not by highly redshifted line emission, and that measurement of black hole spin is not possible.

  14. Inelastic x-ray scattering at the National Synchrotron Light Source

    International Nuclear Information System (INIS)

    The research program at the inelastic x-ray scattering beamline at the National Synchrotron Light Source is focused on the study of elementary excitations in condensed matter with total energy resolution on the order of 0.1 eV to 1.0 eV. Results from selected experiments are reported to demonstrate the capability of the beamline as well as the information that can be obtained from inelastic x-ray scattering experiments. copyright 1996 American Institute of Physics

  15. Scanning soft X-ray spectromicroscopy at the Pohang Light Source: commissioning results

    CERN Document Server

    Shin, H J

    2001-01-01

    A scanning spectromicroscopy facility has been installed at the undulator radiation beamline at the Pohang Light Source. The spectromicroscopy is operational in both the scanning transmission X-ray microscopy (STXM) and the scanning photoelectron microscopy (SPEM) modes. Currently, the measured X-ray spot size on the sample is about 0.4 mu m. The effective photon energy range of the STXM is 250-1000 eV and that of the SPEM is 400-1000 eV. The performance of the facility is presented in this report.

  16. X-ray holographic microscopy experiments at the Brookhaven synchrotron light source

    International Nuclear Information System (INIS)

    Soft x-ray holographic microscopy is discussed from an experimental point of view. Three series of measurements have been carried out using the Brookhaven 750 MeV storage ring as an x-ray source. Young slits fringes, Gabor (in line) holograms and various data measurements are discussed in terms of the technique for recording them and the experimental limitations in effect. Some discussion is also given of the issues involved in reconstruction using visible light. 19 references, 12 figures, 1 table

  17. Search for galactic sources and X-ray bursts with spectrometers of the Kosmos-914 satellite in the energy range of 20-320 keV

    International Nuclear Information System (INIS)

    The results of observations carried out with two scintillation spectrometers of ''Kosmos-914'' satellite used for searches for bursts of galactic hard X-rays are described. The comparison of the results obtained with ''Kosmos-428'' and ''Kosmos-856'' satellites is given. The results of observation of the Whale constellation and the celestial sphere area near the centre of Galaxy are given, where, according to the data of ''Kosmos-428'' satellite the presence of X-ray sources was experted

  18. Channeling and parametric X-ray studies at the SAGA Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Takabayashi, Y., E-mail: takabayashi@saga-ls.jp [SAGA Light Source, 8-7 Yayoigaoka, Tosu, Saga 841-0005 (Japan); Korotchenko, K.B.; Pivovarov, Yu.L.; Tukhfatullin, T.A. [National Research Tomsk Polytechnic University, 634050 Tomsk (Russian Federation)

    2013-11-15

    We present experimental results on channeling and parametric X-ray radiation obtained using a 255-MeV electron beam from an injector linac at the SAGA Light Source. Using a screen monitor, we observed both channeling phenomena and doughnut scattering by measuring the profile of an electron beam transmitted through a 20-μm-thick Si crystal. We also measured the angular distribution of parametric X-ray radiation using an imaging plate as a two-dimensional X-ray detector. The obtained results are in good agreement with theory. The final goal of these studies is the first observation of diffracted channeling radiation, and our strategy for achieving this is discussed.

  19. National Synchrotron Light Source user's manual: Guide to the VUV and x-ray beamlines

    International Nuclear Information System (INIS)

    The success of the National Synchrotron Light Source is based, in large part, on the size of the user community and the diversity of the scientific and technical disciplines represented by these users. As evidence of this success, the VUV Ring has just celebrated its 10th anniversary and the X-ray Ring will do the same in 1995. In order to enhance this success, the NSLS User's Manual: Guide to the VUV and X-Ray Beamlines - Fifth Edition, is being published. This Manual presents to the scientific community-at-large the current and projected architecture, capabilities and research programs of the various VUV and X-ray beamlines. Also detailed is the research and computer equipment a General User can expect to find and use at each beamline when working at the NSLS. The Manual is updated periodically in order to keep pace with the constant changes on these beamlines

  20. Soft x-ray spectromicroscopy development for materials science at the Advanced Light Source

    International Nuclear Information System (INIS)

    Several third generation synchrotron radiation facilities are now operational and the high brightness of these photon sources offers new opportunities for x-ray microscopy. Well developed synchrotron radiation spectroscopy techniques are being applied in new instruments capable of imaging the surface of a material with a spatial resolution smaller than one micron. There are two aspects to this. One is to further the field of surface science by exploring the effects of spatial variations across a surface on a scale not previously accessible to x-ray measurements. The other is to open up new analytical techniques in materials science using x-rays, on a spatial scale comparable to that of the processes or devices to be studied. The development of the spectromicroscopy program at the Advanced Light Source will employ a variety of instruments, some are already operational. Their development and use will be discussed, and recent results will be presented to illustrate their capabilities

  1. Energetics of impulsive solar flares: Correlating BATSE hard x-ray bursts and the solar atmosphere's soft x-ray response

    Science.gov (United States)

    Newton, Elizabeth

    1996-01-01

    This investigation has involved the correlation of BATSE-observed solar hard X-ray emission with the characteristics of soft X-ray emitting plasma observed by the Yohkoh Bragg Crystal Spectrometers. The goal was to test the hypothesis that localized electron beam heating is the dominant energy transport mechanism in impulsive flares, as formulated in the thick-target electron-heated model of Brown.

  2. High-resolution soft-X-ray beamline ADRESS at Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies

    OpenAIRE

    Strocov, V. N.; Schmitt, T; U. Flechsig; Schmidt, T.; Imhof, A; Q. Chen; J. Raabe; Betemps, R.; Zimoch, D.; Krempasky, J.; A. Piazzalunga; X Wang; Grioni, M.; Patthey, L.

    2009-01-01

    We describe the concepts and technical realization of the high-resolution soft-X-ray beamline ADRESS operating in the energy range from 300 to 1600 eV and intended for Resonant Inelastic X-ray Scattering (RIXS) and Angle-Resolved Photoelectron Spectroscopy (ARPES). The photon source is an undulator of novel fixed-gap design where longitudinal movement of permanent magnetic arrays controls not only the light polarization (including circular and 0-180 deg rotatable linear polarizations) but als...

  3. High-resolution soft X-ray beamline ADRESS at the Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies

    OpenAIRE

    Strocov, V. N.; Schmitt, T; U. Flechsig; Schmidt, T.; Imhof, A; Q. Chen; J. Raabe; Betemps, R.; Zimoch, D.; Krempasky, J.; X Wang; Grioni, M.; A. Piazzalunga; Patthey, L.

    2010-01-01

    The concepts and technical realisation of the high-resolution soft X-ray beamline ADRESS operating in the energy range from 300 to 1600 eV and intended for resonant inelastic X-ray scattering (RIXS) and angle-resolved photoelectron spectroscopy (ARPES) are described. The photon source is an undulator of novel fixed-gap design where longitudinal movement of permanent magnetic arrays controls not only the light polarization (including circular and 0–180° rotatable linear polarizations) but also...

  4. X-ray tests of a Pixel Array Detector for coherent x-ray imaging at the Linac Coherent Light Source

    International Nuclear Information System (INIS)

    Test results are presented of a pixel array detector (PAD) developed for x-ray imaging at the Stanford Linear Coherent Light Source (LCLS). The basic module of the PAD consists of two bump-bonded chips: a reverse-biased silicon diode chip of 185 x 194 pixels, each of which is coupled by bump-bonds to a charge integrating CMOS ASIC with digitization in each pixel. The LCLS experiment requires a high signal-to-noise ratio for detection of single 8 keV x-rays, a pixel full-well exceeding 1,000 8 keV x-rays, a frame-rate of 120 Hz, and the ability to handle the arrival of thousands of x-rays per pixel in tens of femtoseconds. Measurements have verified a pixel full-well value of 2,700 8 keV x-rays. Single 8 keV photon detection has been shown with a signal-to-noise ratio of >6. Line-spread response measurements confirmed charge spreading to be limited to nearest neighbor pixels. Modules still functioned after dosages up to 75 Mrad(Si) at the detector face. Work is proceeding to incorporate an array of modules into a large-area detector.

  5. AN EXTENDED AND MORE SENSITIVE SEARCH FOR PERIODICITIES IN ROSSI X-RAY TIMING EXPLORER/ALL-SKY MONITOR X-RAY LIGHT CURVES

    International Nuclear Information System (INIS)

    We present the results of a systematic search in ∼14 years of Rossi X-ray Timing Explorer All-Sky Monitor (ASM) data for evidence of periodicities. Two variations of the commonly used Fourier analysis search method have been employed to significantly improve upon the sensitivity achieved by Wen et al. in 2006, who also searched for periodicities in ASM data. In addition, the present search is comprehensive in terms of sources studied and frequency range covered, and has yielded the detection of the signatures of the orbital periods of eight low-mass X-ray binary systems and of ten high-mass X-ray binaries not listed in the tables of Wen et al. Orbital periods, epochs, signal amplitudes, modulation fractions, and folded light curves are given for each of these systems. Seven of the orbital periods are the most precise reported to date. In the course of this work, the 18.545 day orbital period of IGR J18483-0311 was co-discovered, and the first detections in X-rays were made of the ∼3.9 day orbital period of LMC X-1 and the ∼3.79 hr orbital period of 4U 1636-536. The results inform future searches for orbital and other periodicities in X-ray binaries.

  6. Temperature measurement during thermonuclear X-ray bursts with BeppoSAX

    Science.gov (United States)

    Beri, Aru; Paul, Biswajit; Orlandini, Mauro; Maitra, Chandreyee

    2016-05-01

    We have carried out a study of temperature evolution during thermonuclear bursts in LMXBs using broad band data from two instruments onboard BeppoSAX, the MECSand the PDS. However, instead of applying the standard technique of time resolved spectroscopy, we have determined the temperature in small time intervals using the ratio of count rates in the two instruments assuming a blackbody nature of burst emission and different interstellar absorption for different sources. Data from a total of twelve observations of six sources were analyzed during which 22 bursts were detected. We have obtained temperatures as high as ˜3.0 keV, even when there is no evidence of photospheric radius expansion. These high temperatures were observed in the sources within different broadband spectral states (soft and hard).

  7. Temperature Measurement during Thermonuclear X-ray Bursts with BeppoSAX

    CERN Document Server

    Beri, Aru; Orlandini, Mauro; Maitra, Chandreyee

    2015-01-01

    We have carried out a study of temperature evolution during thermonuclear bursts in LMXBs using broad band data from two instruments onboard BeppoSAX, the MECS and the PDS. However, instead of applying the standard technique of time resolved spectroscopy, we have determined the temperature in small time intervals using the ratio of count rates in the two instruments assuming a blackbody nature of burst emission and different interstellar absorption for different sources. Data from a total of twelve observations of six sources were analysed during which 22 bursts were detected. We have obtained temperatures as high as ~3.0 keV, even when there is no evidence of photospheric radius expansion. These high temperatures were observed in the sources within different broadband spectral states (soft and hard).

  8. MAGNETICALLY DRIVEN WINDS FROM DIFFERENTIALLY ROTATING NEUTRON STARS AND X-RAY AFTERGLOWS OF SHORT GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Besides being among the most promising sources of gravitational waves, merging neutron star binaries also represent a leading scenario to explain the phenomenology of short gamma-ray bursts (SGRBs). Recent observations have revealed a large subclass of SGRBs with roughly constant luminosity in their X-ray afterglows, lasting 10-104 s. These features are generally taken as evidence of a long-lived central engine powered by the magnetic spin-down of a uniformly rotating, magnetized object. We propose a different scenario in which the central engine powering the X-ray emission is a differentially rotating hypermassive neutron star (HMNS) that launches a quasi-isotropic and baryon-loaded wind driven by the magnetic field, which is built-up through differential rotation. Our model is supported by long-term, three-dimensional, general-relativistic, and ideal magnetohydrodynamic simulations, showing that this isotropic emission is a very robust feature. For a given HMNS, the presence of a collimated component depends sensitively on the initial magnetic field geometry, while the stationary electromagnetic luminosity depends only on the magnetic energy initially stored in the system. We show that our model is compatible with the observed timescales and luminosities and express the latter in terms of a simple scaling relation

  9. The dependence of gamma-ray burst X-ray column densities on the model for Galactic hydrogen

    CERN Document Server

    Arcodia, Riccardo; Salvaterra, Ruben

    2016-01-01

    We study the X-ray absorption of a complete sample of 99 bright Swift gamma-ray bursts. Over the last few years, a strong correlation between the intrinsic X-ray absorbing column density (N_H(z)) and the redshift was found. This absorption excess in high-z GRBs is now thought to be due to the overlooked contribution of the absorption along the intergalactic medium, by means of both intervening objects and the diffuse warm-hot intergalactic medium along the line of sight. In this work we neglect the absorption along the IGM, because our purpose is to study the eventual effect of a radical change in the Galactic absorption model on the N_H(z) distribution. Therefore, we derive the intrinsic absorbing column densities using two different Galactic absorption models, the Leiden Argentine Bonn HI survey and the more recent model including molecular hydrogen. We find that, if on the one hand the new Galactic model considerably affects the single column density values, on the other hand there is no drastic change in ...

  10. Prompt Ultraviolet-to-Soft X-Ray Emission of Gamma-Ray Bursts: Application to GRB 031203?

    CERN Document Server

    Li, Z; Li, Zhuo; Song, Li-Ming

    2004-01-01

    We discuss the prompt emission of GRBs, allowing for $\\gamma\\gamma$ pair production and synchrotron self-absorption. The observed hard spectra suggest heavy pair-loading in GRBs. The re-emission of the generated pairs results in the energy transmission from high-energy gamma-rays to long-wavelength radiation. Due to strong self-absorption, the synchrotron radiation by pairs is in optically thick regime. Thus, the re-emission would appear as a thermal-like spectral bump in the extreme-ultraviolet/soft X-ray band, other than the peak from the main burst. Recently, the prompt soft X-ray emission of GRB 031203 was detected thanks to the discovery of a delayed dust echo, and it seems to be consistent with the model prediction of a double-peak structure. The confirmation of the thermal-like feature and the double-peak structure by observation would indicate that the dominant radiation mechanism in GRBs is synchrotron rather than inverse-Compton radiation.

  11. Gigavolt-Energy Electrons and Femtosecond-Duration Hard X-Rays Driven by Extreme Light

    Science.gov (United States)

    Umstadter, Donald

    2012-06-01

    The interactions of high-peak power laser light focused to extremely high intensity, or ``extreme light,'' is at the core of high-energy laser-driven electron accelerators, and novel laser-synchrotron x-ray light sources. The hallmark of extreme light is its ability to cause the instantaneous electron quiver motion to become relativistic. We discuss recent progress in understanding the physics of extreme light, and the advanced electron and x-ray technologies that it drives. Through the mechanism of relativistic self-guiding, focused light from our 100-TW Diocles laser was propagated in plasma at relativistic intensity for distance of 1 cm [corresponding to over 15 vacuum diffraction (Rayleigh) ranges]. As a result of this extended propagation length, electrons were accelerated by a laser-wakefield to near GeV energy in a well-collimated beam. The electron beam was measured to be tunable over a wide energy range, 100 -- 800 MeV, with 5-- 25% energy spread, and 1-- 4-mrad divergence angle. The experimental results were found to be in reasonable agreement with the results of numerical simulation, which predict even higher electron energy (multi-GeV) with our recently upgraded peak laser power (>0.5 PW). These characteristics, along with their lack of any measurable amount of dark-current, make these electron beams good candidates for driving synchrotron x-ray sources. The development of one such x-ray source will also be discussed, one driven by inverse Compton scattering of laser light by laser-accelerated electrons. Its small radiation source size (˜ 10 microns) and low angular beam divergence (radiology. By virtue of its ultra-short pulse duration (< 10 fs) and wide energy tunability (10 keV -- 10 MeV), it can also be used to probe matter with atomic-scale spatial and temporal resolution---simultaneously.

  12. Toward Femtosecond X-ray Spectroscopy at the Advanced Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Chong, Henry Herng Wei

    2004-04-16

    The realization of tunable, ultrashort pulse x-ray sources promises to open new venues of science and to shed new light on long-standing problems in condensed matter physics and chemistry. Fundamentally new information can now be accessed. Used in a pump-probe spectroscopy, ultrashort x-ray pulses provide a means to monitor atomic rearrangement and changes in electronic structure in condensed-matter and chemical systems on the physically-limiting time-scales of atomic motion. This opens the way for the study of fast structural dynamics and the role they play in phase transitions, chemical reactions and the emergence of exotic properties in materials with strongly interacting degrees of freedom. The ultrashort pulse x-ray source developed at the Advanced Light Source at the Lawrence Berkeley Laboratory is based on electron slicing in storage rings, and generates {approx}100 femtosecond pulses of synchrotron radiation spanning wavelengths from the far-infrared to the hard x-ray region of the electromagnetic spectrum. The tunability of the source allows for the adaptation of a broad range of static x-ray spectroscopies to useful pump-probe measurements. Initial experiments are attempted on transition metal complexes that exhibit relatively large structural changes upon photo-excitation and which have excited-state evolution determined by strongly interacting structural, electronic and magnetic degrees of freedom. Specifically, iron(II) complexes undergo a spin-crossover transition upon optical irradiation. The dynamics of the transition involve a metal-to-ligand charge transfer, a {Delta}S=2 change in magnetic moment and 10% bond dilation in the first coordination shell of the iron. Studies of the electronic dynamics are studied with time-resolved optical absorption measurements. The current progress of time-resolved structural studies to complete the picture of the spin-crossover transition is presented.

  13. Toward Femtosecond X-ray Spectroscopy at the Advanced Light Source

    International Nuclear Information System (INIS)

    The realization of tunable, ultrashort pulse x-ray sources promises to open new venues of science and to shed new light on long-standing problems in condensed matter physics and chemistry. Fundamentally new information can now be accessed. Used in a pump-probe spectroscopy, ultrashort x-ray pulses provide a means to monitor atomic rearrangement and changes in electronic structure in condensed-matter and chemical systems on the physically-limiting time-scales of atomic motion. This opens the way for the study of fast structural dynamics and the role they play in phase transitions, chemical reactions and the emergence of exotic properties in materials with strongly interacting degrees of freedom. The ultrashort pulse x-ray source developed at the Advanced Light Source at the Lawrence Berkeley Laboratory is based on electron slicing in storage rings, and generates ∼100 femtosecond pulses of synchrotron radiation spanning wavelengths from the far-infrared to the hard x-ray region of the electromagnetic spectrum. The tunability of the source allows for the adaptation of a broad range of static x-ray spectroscopies to useful pump-probe measurements. Initial experiments are attempted on transition metal complexes that exhibit relatively large structural changes upon photo-excitation and which have excited-state evolution determined by strongly interacting structural, electronic and magnetic degrees of freedom. Specifically, iron(II) complexes undergo a spin-crossover transition upon optical irradiation. The dynamics of the transition involve a metal-to-ligand charge transfer, a ΔS = 2 change in magnetic moment and 10% bond dilation in the first coordination shell of the iron. Studies of the electronic dynamics are studied with time-resolved optical absorption measurements. The current progress of time-resolved structural studies to complete the picture of the spin-crossover transition is presented

  14. Comparative characteristics of electroretinograms induced by light and x-ray stimulation under different adaptation conditions

    International Nuclear Information System (INIS)

    It has been demonstrated previously that the administration of certain chemicals reveals in the X-ray-induced electroretinogram (X-ERG) two electrical processes that are not found in photoinduced electroretinograms. A question arises whether the revealed first and second X-ray reactions are natural and physiological, or whether they are the response to the chemical effect upon the retina or the entire organism of the test animal. The present study investigates changes in electroretinograms induced by X-rays and by red and blue light in the process of the natural dark adaptation of the animals eyes from standard illumination. The results show that the two-component character of X-ERG may be the result not only of the introduction of some specific chemicals, e.g., of sodium axide, monoiodoacetate, or some other specific retinal poisons, but also the result of the natural adaptation of the retina to darkness. They also provide evidence in favor of the earlier hypothesis that postulates that the summary ERG, induced by short X-ray exposure, also includes responses specific for ionizing stimuli

  15. Search for galactic sources of X-ray bursts with scintillation spectrometers of the Kosmos-856 satellite in the energy range of 20-320 keV

    International Nuclear Information System (INIS)

    Search for galactic sources of X-pay bursts with a scintillation spectrometer of ''Kosmos-856'' satellite has given a negative result. During 21 hours of observations with two independent detectors not one burst of X-rays with the energy flux P 2x10-7 erg/cm2 has been found in the energy range 20-320 keV and duration 10s. This result disagrees with the data obtained with the ''Kosmos-428'' satellite

  16. Light-Induced Structural Flexibility of Thylakoid Membranes - Investigated using Small-Angle X-ray and Neutron Scattering

    OpenAIRE

    Aagaard, Thomas Helverskov

    2005-01-01

    Using small-angle x-ray and neutron scattering the light-induced structural changes in pea thylakoids have been investigated. It is shown that light-induced shinkage in the thylakoids is connected to photosynthetic electron transduction.

  17. National Synchrotron Light Source users manual: Guide to the VUV and x-ray beam lines

    International Nuclear Information System (INIS)

    The success of the National Synchrotron Light Source in the years to come will be based, in large part, on the size of the users community and the diversity of the scientific disciplines represented by these users. In order to promote this philosophy, this National Synchrotron Light Source (NSLS) Users Manual: Guide to the VUV and X-Ray Beam Lines, has been published. This manual serves a number of purposes. In an effort to attract new research, it will present to the scientific community-at-large the current and projected architecture and capabilities of the various VUV and x-ray beam lines and storage rings. We anticipate that this publication will be updated periodically in order to keep pace with the constant changes at the NSLS

  18. Quasi-Periodic Oscillations in the X-ray Light Curves of Blazars

    Indian Academy of Sciences (India)

    Paul J. Wiita

    2011-03-01

    Any quasi-periodic variations discovered in blazar light curves would contain important information on the location and nature of the processes within the emission regions. In non-blazar active galactic nuclei, particularly Seyfert galaxies, any such fluctuations are very likely to be associated with the accretion disks, but in blazars they would almost certainly have to emanate from jets. This brief review summarizes recent claims for the presence of quasi-periodic variability in the X-ray emission of several AGN, focusing on blazars. Although no individual claim of the presence of a QPO in AGN X-ray light curves is absolutely convincing, there are some good cases for the presence of QPOs, including the Narrow Line Seyfert 1 galaxy, RE J1034+396, the quasar, 3C 273 and the BL Lac, PKS 2155−304.

  19. Propagation of thermonuclear flames on rapidly rotating neutron stars extreme weather during type I X-ray bursts

    CERN Document Server

    Spitkovsky, A; Ushomirsky, G; Spitkovsky, Anatoly; Levin, Yuri; Ushomirsky, Greg

    2002-01-01

    We analyze the global hydrodynamic flow in the ocean of an accreting, rapidly rotating, non-magnetic neutron star in an LMXB during a type I X-ray burst. Our analysis takes into account the rapid rotation of the star and the lift-up of the burning ocean during the burst. We find a new regime for spreading of a nuclear burning front, where the flame is carried along a coherent shear flow across the front. If turbulent viscosity is weak, the speed of flame propagation is ~20 km/s, while, if turbulent viscosity is dynamically important, the flame speed increases, and reaches the maximum value, ~300 km/s, when the eddy overturn frequency is comparable to the Coriolis parameter. We show that, due to rotationally reduced gravity, the thermonuclear runaway is likely to begin on the equator. The equatorial belt is ignited first, and the flame then propagates from the equator to the poles. Inhomogeneous cooling (equator first, poles second) drives strong zonal currents which may be unstable to formation of Jupiter-typ...

  20. Two types of softening detected in X-ray afterglows of Swift bursts: internal and external shock origins?

    CERN Document Server

    Qin, Y -P; Fan, J H; Lu, R -J

    2008-01-01

    The softening process observed in the steep decay phase of early X-ray afterglows of Swift bursts has remained a puzzle since its discovery. The softening process can also be observed in the later phase of the bursts and its cause has also been unknown. Recently, it was suggested that, influenced by the curvature effect, emission from high latitudes would shift the Band function spectrum from higher energy band to lower band, and this would give rise to the observed softening process accompanied by a steep decay of the flux density. The curvature effect scenario predicts that the terminating time of the softening process would be correlated with the duration of the process. In this paper, based on the data from the UNLV GRB group web-site, we found an obvious correlation between the two quantities. In addition, we found that the softening process can be divided into two classes: the early type softening ($t_{s,max}\\leq "4000"s$) and the late type softening ($t_{s,max} > "4000"s$). The two types of softening s...

  1. Interaction delocalization in characteristic X-ray emission from light elements

    International Nuclear Information System (INIS)

    Experimental results for characteristic X-ray emission in spinel are reported. Calculations of ionization cross sections and the effective ionization potential for each of the constituent atoms of the spinel MgAlsO4 have been carried out. This allows a quantitative theoretical insight into the channelling effect for the light elements Al, Mg and O which incorporates delocalization of the ionization interaction. 33 refs., 6 figs

  2. Synchrotron X-Ray Microdiffraction Studies of Electromigration in Interconnect lines at the Advanced Light Source

    OpenAIRE

    Tamura, Nobumichi

    2009-01-01

    Synchrotron polychromatic X-ray microdiffraction is a particularly suitable technique to study in situ the effect of electromigration in metal interconnects as add spatial resolution to grain orientation and strain sensitivity. This technique has been extensively used at the Advanced Light Source to monitor changes in aluminum and copper interconnect test structures while high-density current is passed into them during accelerated tests at elevated temperature. One of the principal findings i...

  3. X-ray light valve (XLV): a novel detectors' technology for digital mammography

    Science.gov (United States)

    Marcovici, Sorin; Sukhovatkin, Vlad; Oakham, Peter

    2014-03-01

    A novel method, based on X-ray Light Valve (XLV) technology, is proposed for making good image quality yet inexpensive flat panel detectors for digital mammography. The digital mammography markets, particularly in the developing countries, demand quality machines at substantially lower prices than the ones available today. Continuous pressure is applied on x-ray detectors' manufacturers to reduce the flat panel detectors' prices. XLV presents a unique opportunity to achieve the needed price - performance characteristics for direct conversion, x-ray detectors. The XLV based detectors combine the proven, superior, spatial resolution of a-Se with the simplicity and low cost of liquid crystals and optical scanning. The x-ray quanta absorbed by a 200 μm a-Se produce electron - hole pairs that move under an electric field to the top and bottom of a-Se layer. This 2D charge distribution creates at the interface with the liquid crystals a continuous (analog) charge image corresponding to the impinging radiation's information. Under the influence of local electrical charges next to them, the liquid crystals twist proportionally to the charges and vary their light reflectivity. A scanning light source illuminates the liquid crystals while an associated, pixilated photo-detector, having a 42 μm pixel size, captures the light reflected by the liquid crystals and converts it in16 bit words that are transmitted to the machine for image processing and display. The paper will describe a novel XLV, 25 cm x 30 cm, flat panel detector structure and its underlying physics as well as its preliminary performance measured on several engineering prototypes. In particular, the paper will present the results of measuring XLV detectors' DQE, MTF, dynamic range, low contrast resolution and dynamic behavior. Finally, the paper will introduce the new, low cost, XLV detector based, digital mammography machine under development at XLV Diagnostics Inc.

  4. The killing effects of ultraviolet light and x-rays on free-living nematode, Rhabditidae tokai

    International Nuclear Information System (INIS)

    The life-shortening effects of ultraviolet light (UV) and X-rays were investigated with a strain of free-living nematode, Rhabditidae tokai. UV exhibited a significant life-shortening effect on adult worms, and it also inhibited growth of larvae, hatching of eggs and reproduction. Sensitivity to UV was decreased with increasing ages. In contrast, nematodes showed a marked resistance to X-rays. Data were obtained suggesting that X-ray-induced single-strand breaks in DNA can be rapidly and efficiently rejoined by a repair mechanism. Malformations were observed when immature larvae were irradiated with X-rays. (author)

  5. Proposal to DOE Basic Energy Sciences: Ultrafast X-ray science facility at the Advanced Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Schoenlein, Robert W.; Falcone, Roger W.; Abela, R.; Alivisatos, A.P.; Belkacem, A.; Berrah, N.; Bozek, J.; Bressler, C.; Cavalleri, A.; Chergui, M.; Glover, T.E.; Heimann, P.A.; Hepburn, J.; Larsson, J.; Lee, R.W.; McCusker, J.; Padmore, H.A.; Pattison, P.; Pratt, S.T.; Shank, C.V.; Wark, J.; Chang, Z.; Robin, D.W.; Schlueter, R.D.; Zholents, A.A.; Zolotorev, M.S.

    2001-12-12

    We propose to develop a true user facility for ultrafast x-ray science at the Advanced Light Source. This facility will be unique in the world, and will fill a critical need for the growing ultrafast x-ray research community. The development of this facility builds upon the expertise from long-standing research efforts in ultrafast x-ray spectroscopy and the development of femtosecond x-ray sources and techniques at both the Lawrence Berkeley National Laboratory and at U.C. Berkeley. In particular, the technical feasibility of a femtosecond x-ray beamline at the ALS has already been demonstrated, and existing ultrafast laser technology will enable such a beamline to operate near the practical limit for femtosecond x-ray flux and brightness from a 3rd generation synchrotron.

  6. Proposal to DOE Basic Energy Sciences: Ultrafast X-ray science facility at the Advanced Light Source

    International Nuclear Information System (INIS)

    We propose to develop a true user facility for ultrafast x-ray science at the Advanced Light Source. This facility will be unique in the world, and will fill a critical need for the growing ultrafast x-ray research community. The development of this facility builds upon the expertise from long-standing research efforts in ultrafast x-ray spectroscopy and the development of femtosecond x-ray sources and techniques at both the Lawrence Berkeley National Laboratory and at U.C. Berkeley. In particular, the technical feasibility of a femtosecond x-ray beamline at the ALS has already been demonstrated, and existing ultrafast laser technology will enable such a beamline to operate near the practical limit for femtosecond x-ray flux and brightness from a 3rd generation synchrotron

  7. Compact x-ray source based on burst-mode inverse Compton scattering at 100 kHz

    OpenAIRE

    Graves, W. S.; Bessuille, J.; Brown, P.; Carbajo, S.; Dolgashev, V.; Hong, K. -H.; Ihloff, E.; Khaykovich, B.; H. Lin; Murari, K.; Nanni, E. A.; RESTA, G.; Tantawi, S.; Zapata, L. E.; Kärtner, F. X.

    2014-01-01

    A design for a compact x-ray light source (CXLS) with flux and brilliance orders of magnitude beyond existing laboratory scale sources is presented. The source is based on inverse Compton scattering of a high brightness electron bunch on a picosecond laser pulse. The accelerator is a novel high-efficiency standing-wave linac and rf photoinjector powered by a single ultrastable rf transmitter at X-band rf frequency. The high efficiency permits operation at repetition rates up to 1 kHz, which i...

  8. X-ray flares from propagation instabilities in long Gamma-Ray Burst jets

    OpenAIRE

    Lazzati, Davide; Blackwell, Chris H.; Morsony, Bran J.; Begelman, Mitch C.

    2010-01-01

    We present a numerical simulation of a gamma-ray burst jet from a long-lasting engine in the core of a 16 solar mass Wolf-Rayet star. The engine is kept active for 6000 s with a luminosity that decays in time as a power-law with index -5/3. Even though there is no short time-scale variability in the injected engine luminosity, we find that the jet's kinetic luminosity outside the progenitor star is characterized by fluctuations with relatively short time scale. We analyze the temporal charact...

  9. High-brightness beamline for X-ray spectroscopy at the advanced light source

    International Nuclear Information System (INIS)

    Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range, designed to achieve the goals of high energy resolution, high flux, and high brightness at the sample. When completed later this year, it will be the first ALS monochromatic hard-x-ray beamline, and its brightness will be an order-of-magnitude higher than presently available in this energy range. In addition, it will provide flux and resolution comparable to any other beamline now in operation. To achieve these goals, two technical improvements, relative to existing x-ray beamlines, were incorporated. First, a somewhat novel optical design for x-rays, in which matched toroidal mirrors are positioned before and after the double-crystal monochromator, was adopted. This configuration allows for high resolution by passing a collimated beam through the monochromator, and for high brightness by focusing the ALS source on the sample with unit magnification. Second, a new open-quotes Cowan typeclose quotes double-crystal monochromator based on the design used at NSLS beamline X-24A was developed. The measured mechanical precision of this new monochromator shows significant improvement over existing designs, without using positional feedback available with piezoelectric devices. Such precision is essential because of the high brightness of the radiation and the long distance (12m) from the source (sample) to the collimating (focusing) mirror. This combination of features will provide a bright, high resolution, and stable x-ray beam for use in the x-ray spectroscopy program at the ALS

  10. Two types of softening detected in x-ray afterglows of Swift bursts: internal and external shock origins?

    International Nuclear Information System (INIS)

    The softening process observed in the steep decay phase of early x-ray afterglows of Swift bursts has remained a puzzle since its discovery. The softening process can also be observed in the later phase of the bursts and its cause has also been unknown. Recently, it was suggested that, influenced by the curvature effect, emission from high latitudes would shift the Band function spectrum from a higher energy band to a lower band, and this would give rise to the observed softening process accompanied by a steep decay of the flux density. The curvature effect scenario predicts that the terminating time of the softening process would be correlated with the duration of the process. In this paper, on the basis of the data from the UNLV GRB (University of Nevada, Las Vegas, Gamma-Ray Burst) group web-site, we found an obvious correlation between the two quantities. In addition, we found that the softening process can be divided into two classes: the early type softening (ts,max≤'4000' s) and the late type softening (ts,max>'4000' s). The two types of softening show different behaviors in the duration versus terminating time plot. In the relation between the variation rates of the flux density and spectral index during the softening process, a discrepancy between the two types of softening is also observed. According to their timescales and the discrepancy between them, we propose that the two types are of different origins: the early type is of internal shock origin and the late type is of external shock origin. The early softening is related to the steep decay just following the prompt emission, whereas for the late decay one typically conceives the transition from flat decay to late afterglow decay. We suspect that there might be a great difference in Lorentz factor between the two classes, which is responsible for the observed discrepancy

  11. Evidence for Harmonic Content and Frequency Evolution of Oscillations During the Rising Phase of X-ray Bursts From 4U 1636-536

    Science.gov (United States)

    Bgattacharyya, Sudip; Strohmayer, E.

    2005-01-01

    We report on a study of the evolution of burst oscillation properties during the rising phase of X-ray bursts from 4U 1636-536 observed with the proportional counter array (PCA) on board the Rossi X-Ray Timing Explorer (RXTE) . We present evidence for significant harmonic structure of burst oscillation pulses during the early rising phases of bursts. This is the first such detection in burst rise oscillations, and is very important for constraining neutron star structure parameters and the equation of state models of matter at the core of a neutron star. The detection of harmonic content only during the initial portions of the burst rise is consistent with the theoretical expectation that with time the thermonuclear burning region becomes larger, and hence the fundamental and harmonic amplitudes both diminish. We also find, for the first time from this source, strong evidence of oscillation frequency increase during the burst rise. The timing behavior of harmonic content, amplitude, and frequency of burst rise oscillations may be important in understanding the spreading of thermonuclear flames under the extreme physical conditions on neutron star surfaces.

  12. The dependence of gamma-ray burst X-ray column densities on the model for Galactic hydrogen

    Science.gov (United States)

    Arcodia, R.; Campana, S.; Salvaterra, R.

    2016-05-01

    We study the X-ray absorption of a complete sample of 99 bright Swift gamma-ray bursts (GRBs). In recent years, a strong correlation has been found between the intrinsic X-ray absorbing column density (NH(z)) and the redshift. This absorption excess in high-z GRBs is now thought to be due to the overlooked contribution of the absorption along the intergalactic medium (IGM), by means of both intervening objects and the diffuse warm-hot intergalactic medium along the line of sight. In this work we neglect the absorption along the IGM, because our purpose is to study the eventual effect of a radical change in the Galactic absorption model on the NH(z) distribution. Therefore, we derive the intrinsic absorbing column densities using two different Galactic absorption models: the Leiden Argentine Bonn HI survey and the more recent model that includes molecular hydrogen. We find that if, on the one hand, the new Galactic model considerably affects the single column density values, on the other hand, there is no drastic change in the distribution as a whole. It becomes clear that the contribution of Galactic column densities alone, no matter how improved, is not sufficient to change the observed general trend and it has to be considered as a second order correction. The cosmological increase of NH(z) as a function of redshift persists and, to explain the observed distribution, it is necessary to include the contribution of both the diffuse intergalactic medium and the intervening systems along the line of sight of the GRBs.

  13. Chandra Observations of SN 1987A: The Soft X-Ray Light Curve Revisited

    Science.gov (United States)

    Helder, E. A.; Broos, P. S.; Dewey, D.; Dwek, E.; McCray, R.; Park, S.; Racusin, J. L.; Zhekov, S. A.; Burrows, D. N.

    2013-01-01

    We report on the present stage of SN 1987A as observed by the Chandra X-Ray Observatory. We reanalyze published Chandra observations and add three more epochs of Chandra data to get a consistent picture of the evolution of the X-ray fluxes in several energy bands. We discuss the implications of several calibration issues for Chandra data. Using the most recent Chandra calibration files, we find that the 0.5-2.0 keV band fluxes of SN 1987A have increased by approximately 6 x 10(exp-13) erg s(exp-1)cm(exp-2) per year since 2009. This is in contrast with our previous result that the 0.5-2.0 keV light curve showed a sudden flattening in 2009. Based on our new analysis, we conclude that the forward shock is still in full interaction with the equatorial ring.

  14. A Superbend X-Ray Microdiffraction Beamline at the Advanced Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, N.; Kunz, M.; Chen, K.; Celestre, R.S.; MacDowell, A.A.; Warwick, T.

    2009-03-10

    Beamline 12.3.2 at the Advanced Light Source is a newly commissioned beamline dedicated to x-ray microdiffraction. It operates in both monochromatic and polychromatic radiation mode. The facility uses a superconducting bending magnet source to deliver an X-ray spectrum ranging from 5 to 22 keV. The beam is focused down to {approx} 1 um size at the sample position using a pair of elliptically bent Kirkpatrick-Baez mirrors enclosed in a vacuum box. The sample placed on high precision stages can be raster-scanned under the microbeam while a diffraction pattern is taken at each step. The arrays of diffraction patterns are then analyzed to derive distribution maps of phases, strain/stress and/or plastic deformation inside the sample.

  15. A superbend X-ray microdiffraction beamline at the advanced light source

    International Nuclear Information System (INIS)

    Beamline 12.3.2 at the Advanced Light Source (ALS) is a newly commissioned beamline dedicated to X-ray microdiffraction. It operates in both monochromatic and polychromatic radiation mode. The facility uses a superconducting bending magnet source to deliver an X-ray spectrum ranging from 5 to 22 keV. The beam is focused down to ∼1 μm size at the sample position using a pair of elliptically bent Kirkpatrick-Baez (KB) mirrors enclosed in a vacuum box. The sample placed on high precision stages can be raster-scanned under the microbeam while a diffraction pattern is taken at each step. The arrays of diffraction patterns are then analyzed to derive distribution maps of phases, strain/stress and/or plastic deformation inside the sample.

  16. Deka-keV X-ray observations of solar bursts with WATCH/GRANAT: frequency distributions of burst parameters

    DEFF Research Database (Denmark)

    Crosby, N.; Vilmer, N.; Lund, Niels;

    1998-01-01

    Solar flare observations in the deka-keV range are performed by the WATCH experiment on board the GRANAT satellite. The WATCH experiment is presented, including the energy calibration as applied in the present work. The creation of the solar burst catalogue covering two years of observation is...... contributions from a thermal plasma around a few keV. Either a hotter component or a non-thermal population of particles must also be present to produce the observed deka-keV emission. The WATCH data furthermore shows that the relative contributions of these components may change during an event or from event...... to event and that the injection of energy contained in suprathermal electrons may occur throughout an event and not only during the rise phase. For the most energetic WATCH flares simultaneous observations performed by other experiments at higher energies further indicate that non-thermal emission...

  17. NuSTAR OBSERVATION OF A TYPE I X-RAY BURST FROM GRS 1741.9-2853

    International Nuclear Information System (INIS)

    We report on two NuSTAR observations of GRS 1741.9-2853, a faint neutron star (NS) low-mass X-ray binary burster located 10' away from the Galactic center. NuSTAR detected the source serendipitously as it was emerging from quiescence: its luminosity was 6 × 1034 erg s–1 on 2013 July 31 and 5 × 1035 erg s–1 in a second observation on 2013 August 3. A bright, 800 s long, H-triggered mixed H/He thermonuclear Type I burst with mild photospheric radius expansion (PRE) was present during the second observation. Assuming that the luminosity during the PRE was at the Eddington level, an H mass fraction X = 0.7 in the atmosphere, and an NS mass M = 1.4 M ☉, we determine a new lower limit on the distance for this source of 6.3 ± 0.5 kpc. Combining with previous upper limits, this places GRS 1741.9-2853 at a distance of 7 kpc. Energy independent (achromatic) variability is observed during the cooling of the NS, which could result from the disturbance of the inner accretion disk by the burst. The large dynamic range of this burst reveals a long power-law decay tail. We also detect, at a 95.6% confidence level (1.7σ), a narrow absorption line at 5.46 ± 0.10 keV during the PRE phase of the burst, reminiscent of the detection by Waki et al. We propose that the line, if real, is formed in the wind above the photosphere of the NS by a resonant Kα transition from H-like Cr gravitationally redshifted by a factor 1 + z = 1.09, corresponding to a radius range of 29.0-41.4 km for a mass range of 1.4-2.0 M ☉

  18. Characteristic studies on solar x-ray flares and solar radio bursts during descending phases of solar cycles 22 and 23

    International Nuclear Information System (INIS)

    In this paper, a comparative study between the solar X-ray flares and solar radio bursts in terms of their duration and energy has been done. This has been done by analyzing the data in a statistical way covering the descending phase of the 22nd and 23rd solar cycles. It has been observed that the most probable value of duration of both solar X-ray flares and solar radio bursts remain same for a particular cycle. There is a slight variation in the most probable value of duration in going from 22nd cycle to 23rd cycle in the case of both kinds of events. This small variation may be due to the variation of polar field. A low correlation has been observed between energy fluxes in solar X-ray flares and in solar radio bursts. This has been attributed to the non symmetric contribution of energy to the solar radio and X-ray band controlled by solar magnetic field

  19. Discovery of Giant X-Ray Disk Sheds Light on Elliptical Galaxies

    Science.gov (United States)

    2002-12-01

    Ohio University astronomers have discovered the largest disk of hot, X-ray emitting gas ever observed in the universe: At 90,000 light years in diameter, it's about 100,000 times the size of any comparable object. The disk, spinning through a distant galaxy, is more than just an interstellar oddity, the researchers say. The object could offer new information about the way certain galaxies form and evolve. About 20 percent of all galaxies are elliptical, the largest of the three types of galaxies in the universe. They differ from spiral galaxies like the Milky Way, as they lack new stars and spiral "arms." Scientists once believed that elliptical galaxies were ancient, simple systems that contained only old stars and formed in the early days of the universe. But new research suggests elliptical galaxies are more complex and dynamic. "It used to be thought that galaxies form and then sit there and age quietly over time. But now we understand that galaxies live, in the sense that there's an interplay of gas and stars," said Thomas Statler, an associate professor of physics and astronomy and lead author of the study, published in the Dec. 20 issue of the Astrophysical Journal. The newly discovered X-ray disk offers more evidence for that argument. Using NASA's Chandra X-ray Observatory, an orbiting spacecraft that houses the most powerful X-ray telescope in existence, the astronomers discovered the disk while analyzing data collected from NGC 1700, a young elliptical galaxy about 160 million light years from Earth. Giant in size and about 8 million degrees in temperature, the disk was an unexpected find for Statler and colleague Brian McNamara. But while its gargantuan scale is striking, the disk also yielded another surprise: The hot gas is not in calm balance with the gravitational forces as expected, but spinning through the galaxy. In fact, the giant, rotating X-ray disk suggests that this elliptical galaxy and perhaps others like it wasn't created by the merger of

  20. The Coherent X-ray Imaging (CXI) Instrument at the Linac Coherent Light Source (LCLS)

    Energy Technology Data Exchange (ETDEWEB)

    Boutet, Sebastien; Williams, Garth J.; /SLAC

    2011-08-16

    The Linac Coherent Light Source (LCLS) has become the first ever operational hard X-ray Free Electron Laser in 2009. It will operate as a user facility capable of delivering unique research opportunities in multiple fields of science. The LCLS and the LCLS Ultrafast Science Instruments (LUSI) construction projects are developing instruments designed to make full use of the capabilities afforded by the LCLS beam. One such instrument is being designed to utilize the LCLS coherent beam to image with high resolution any sub-micron object. This instrument is called the Coherent X-ray Imaging (CXI) instrument. This instrument will provide a flexible optical system capable of tailoring key beam parameters for the users. A suite of shot-to-shot diagnostics will also be provided to characterize the beam on every pulse. The provided instrumentation will include multi-purpose sample environments, sample delivery and a custom detector capable of collecting 2D data at 120 Hz. In this article, the LCLS will be briefly introduced along with the technique of Coherent X-ray Diffractive Imaging (CXDI). A few examples of scientific opportunities using the CXI instrument will be described. Finally, the conceptual layout of the instrument will be presented along with a description of the key requirements for the overall system and specific devices required.

  1. X-ray absorption evolution in Gamma-Ray Bursts: intergalactic medium or evolutionary signature of their host galaxies?

    CERN Document Server

    Starling, R L C; Tanvir, N R; Scott, A E; Wiersema, K; O'Brien, P T; Levan, A J; Stewart, G C

    2013-01-01

    The intrinsic X-ray emission of Gamma-Ray Bursts (GRBs) is often found to be absorbed over and above the column density through our own galaxy. The extra component is usually assumed to be due to absorbing gas lying within the host galaxy of the GRB itself. There is an apparent correlation between the equivalent column density of hydrogen, N(H,intrinsic) (assuming it to be at the GRB redshift), and redshift, z, with the few z>6 GRBs showing the greatest intrinsic column densities. We investigate the N(H,intrinsic) - z relation using a large sample of Swift GRBs, as well as active galactic nuclei (AGN) and quasar samples, paying particular attention to the spectral energy distributions of the two highest redshift GRBs. Various possible sample biases and systematics that might produce such a correlation are considered, and we conclude that the correlation is very likely to be real. This may indicate either an evolutionary effect in the host galaxy properties, or a contribution from gas along the line-of-sight, ...

  2. Observational Signatures of High-Energy Emission during the Shallow Decay Phase of Gamma-Ray Burst X-Ray Afterglows

    Science.gov (United States)

    Yu, Y. W.; Liu, X. W.; Dai, Z. G.

    2007-12-01

    The widely existing shallow decay phase of the X-ray afterglows of gamma-ray bursts (GRBs) is generally accepted to be due to long-lasting energy injection. The outflows carrying the injecting energy, based on the component that is dominant in energy, fall into two possible types: baryon-dominated and lepton-dominated ones. The former type of outflow could be ejecta that is ejected during the prompt phase of a GRB and consists of a series of baryonic shells with a distribution of Lorentz factors, and the latter type could be an electron-positron pair wind that is driven by the postburst central engine. We here provide a unified description for the dynamics of fireballs based on these two types of energy injection and calculate the corresponding high-energy photon emission by considering synchrotron radiation and inverse Compton scattering (including synchrotron self-Compton and combined inverse Compton) of electrons. We find that, in the two energy-injection models, there is a plateau (even a hump) in high-energy light curves during the X-ray shallow decay phase. In particular, a considerable fraction of the injecting energy in the lepton-dominated model can be shared by the long-lasting reverse shock since it is relativistic. Furthermore, almost all of the energy of the reverse shock is carried by leptons, and thus, the inverse Compton emission is enhanced dramatically. Therefore, this model predicts more significant high-energy afterglow emission than the baryon-dominated model. We argue that these observational signatures would be used to discriminate between different energy-injection models in the upcoming Gamma-Ray Large Area Space Telescope (GLAST) era.

  3. Temperature dependent x-ray diffraction study of lightly doped NaxWO3

    International Nuclear Information System (INIS)

    Temperature dependent x-ray diffraction studies have been carried out on nonstoichiometric lightly doped sodium tungsten bronze (NaxWO3 for x=0.025). The investigation reveals a structural modification around 230 K. Although the high and low temperature phases are monoclinic but at low temperature the corner sharing WO6 octahedra get significantly distorted due to displacement of tungsten and oxygen atoms from its mean position. This structural modification induces polaron formation in Na0.025WO3 below 230 K.

  4. Optimization of the soft x-ray transmission microscopy beamline at the ALBA light source

    Science.gov (United States)

    Sorrentino, Andrea; Pereiro, Eva; Valcárcel, Ricardo; Ferrer, Salvador; Nicolas, Josep

    2013-09-01

    Mistral is the soft X-ray full field microscopy beamline at the ALBA light source. The beamline is designed to have large source acceptance and to provide constant magnification at the exit slit for photon energies between 270 and 2600 eV. The monochromator is a variation of the Petersen plane grating monochromator in which a variable line spacing grating is used to maintain the beam focused at the exit slit, independently of the fixed focus constant, and to cancel aberrations. We present the alignment strategy used to compensate errors of the optical elements, and report about the commissioning results.

  5. Inactivation of bacteriophage lambda by combined X-ray and U.V.-light exposure

    International Nuclear Information System (INIS)

    Extracellular phage lambda has been successively exposed to X-rays and U.V. light. The plaque-forming ability of the irradiated phages was determined on host cells with different repair capacities. No change in sensitivity was found with a pre-treatment of one type of radiation to lethal damage inflicted by the other. This indicates that a prerequisite for an interaction of different types of radiation is either an active metabolism or repair process occurring during the two radiation exposures. (author)

  6. High Resolution X-Ray and Light Scattering Studies of Bilayer Smectic A Compounds

    DEFF Research Database (Denmark)

    Litster, J. D.; Als-Nielsen, Jens Aage; Birgeneau, R. J.;

    1979-01-01

    We summarize the results of high resolution X-ray and light scattering studies of the smectic A-nematic transition in cyanobenzylidene-octyloxyaniline, octyloxy-cyanobiphenyl, and octyl-cyanobiphenyl. Pretransitional behavior in the nematic phase is essentially consistent with the He4 analogue pr...... proposed by de Gennes with subtle effects arising from the lack of true long range order in the smectic phase. Elastic constants in the smectic phase show anomalous behavior probably associated with the logarithmically divergent phase fluctuations....

  7. Phase shifts and nonellipsoidal light curves: Challenges from mass determinations in x-ray binary stars

    Science.gov (United States)

    Cantrell, Andrew Glenn

    We consider two types of anomalous observations which have arisen from efforts to measure dynamical masses of X-ray binary stars: (1) Radial velocity curves which seemingly show the primary and the secondary out of antiphase in most systems, and (2) The observation of double-waved light curves which deviate significantly from the ellipsoidal modulations expected for a Roche lobe filling star. We consider both problems with the joint goals of understanding the physical origins of the anomalous observations, and using this understanding to allow robust dynamical determinations of mass in X-ray binary systems. In our analysis of phase-shifted radial velocity curves, we discuss a comprehensive sample of X-ray binaries with published phase-shifted radial velocity curves. We show that the most commonly adopted explanation for phase shifts is contradicted by many observations, and consider instead a generalized form of a model proposed by Smak in 1970. We show that this model is well supported by a range of observations, including some systems which had previously been considered anomalous. We lay the groundwork for the derivation of mass ratios based on our explanation for phase shifts, and we discuss the work necessary to produce more detailed physical models of the phase shift. In our analysis of non-ellipsoidal light curves, we focus on the very well-studied system A0620-00. We present new VIH SMARTS photometry spanning 1999-2007, and supplement this with a comprehensive collection of archival data obtained since 1981. We show that A0620-00 undergoes optical state changes within X-ray quiescence and argue that not all quiescent data should be used for determinations of the inclination. We identify twelve light curves which may reliably be used for determining the inclination. We show that the accretion disk contributes significantly to all twelve curves and is the dominant source of nonellipsoidal variations. We derive the disk fraction for each of the twelve curves

  8. The experimental station for white beam X-ray topography at the synchrotron light source ANKA, Karlsruhe

    CERN Document Server

    Simon, R

    2003-01-01

    At the recently constructed synchrotron radiation facility ANKA at Karlsruhe, Germany, two end stations for X-ray fluorescence and X-ray topography, respectively, are integrated into one beamline offering white light as well as band pass operation. This contribution is focussed on the design, characteristics and performance parameters of this beamline with special reference to experiments in X-ray topography. Results of characterization measurements of the horizontal and vertical beam profile, the source dimension and of components of the experimental stations are presented.

  9. Hydrodynamics associated to the X-ray light curve of A0620-00

    Science.gov (United States)

    Coronado, Y.; Mendoza, S.

    2015-12-01

    From 1975 to 1976, an outburst was detected in the light curve of the X-ray transient A0620-00 using the Ariel V and SAS-3 experiments. In this article we model the outburst with the hydrodynamical model proposed by Mendoza et al. (Mon. Not. R. Astron. Soc. 395:1403, 2009). The physical model is constructed assuming basic mass and momentum conservation laws associated to the motion of the shock waves developed inside the expanding relativistic jet of the source. These internal shock waves are produced as a result of periodic variations of the injected mass and velocity of the flow at the base of the jet. The observations of this X-ray light curve present two clear bumps. The first one is modelled assuming periodic variations of the injected velocity at the base of the jet, while the second one can either be modelled by further velocity oscillations, or by a periodic variation of the mass injection rate at the base of the jet at a latter time. This latter model is statistically more significant for the observed data, than the former. The fitting of the data fixes different parameters of the model, such as the mean mass injection rate at the base of the jet and the oscillation frequency of the flow as measured on the rest frame of the central source.

  10. A synchrotron/inverse Compton interpretation of a solar burst producing fast pulses at λ < 3 mm and hard X-rays

    International Nuclear Information System (INIS)

    The recently discovered new class of solar burst emission component exhibiting very fast pulses (durations ∼ 60 ms) at mm-waves only (λ 13 Hz, the burst sources must be short lived (∼ 60 ms), very small (7cm) and exhibiting high apparent brightness temperature (> or approx. 1010 K). This study suggest further theoretical studies on the nature of the primary acceleration sources, and on their location in the solar atmosphere. A number of crucial observational tests are needed, specially in the sub-mm and infrared range of frequencies, as well as at ratio and hard X-rays with simultaneous high spatial and time resolution. (Author)

  11. LCLS X-ray mirror measurements using a large aperture visible light interferometer

    Energy Technology Data Exchange (ETDEWEB)

    McCarville, T; Soufli, R; Pivovaroff, M

    2011-03-02

    Synchrotron or FEL X-ray mirrors are required to deliver an X-ray beam from its source to an experiment location, without contributing significantly to wave front distortion. Accurate mirror figure measurements are required prior to installation to meet this intent. This paper describes how a 300 mm aperture phasing interferometer was calibrated to <1 nm absolute accuracy and used to mount and measure 450 mm long flats for the Linear Coherent Light Source (LCLS) at Stanford Linear Accelerator Center. Measuring focus mirrors with an interferometer requires additional calibration, because high fringe density introduces systematic errors from the interferometer's imaging optics. This paper describes how these errors can be measured and corrected. The calibration approaches described here apply equally well to interferometers larger than 300 mm aperture, which are becoming more common in optics laboratories. The objective of this effort was to install LCLS flats with < 10 nm of spherical curvature, and < 2 nm rms a-sphere. The objective was met by measuring the mirrors after fabrication, coating and mounting, using a 300 mm aperture phasing interferometer calibrated to an accuracy < 1 nm. The key to calibrating the interferometer accurately was to sample the error using independent geometries that are available. The results of those measurements helped identify and reduce calibration error sources. The approach used to measure flats applies equally well to focus mirrors, provided an additional calibration is performed to measure the error introduced by fringe density. This calibration has been performed on the 300 mm aperture interferometer, and the measurement correction was evaluated for a typical focus mirror. The 300 mm aperture limitation requires stitching figure measurements together for many X-ray mirrors of interest, introducing another possible error source. Stitching is eliminated by applying the calibrations described above to larger aperture

  12. High-resolution soft-X-ray beamline ADRESS at Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies

    CERN Document Server

    Strocov, V N; Flechsig, U; Schmidt, T; Imhof, A; Chen, Q; Raabe, J; Betemps, R; Zimoch, D; Krempasky, J; Piazzalunga, A; Wang, X; Grioni, M; Patthey, L

    2009-01-01

    We describe the concepts and technical realization of the high-resolution soft-X-ray beamline ADRESS operating in the energy range from 300 to 1600 eV and intended for Resonant Inelastic X-ray Scattering (RIXS) and Angle-Resolved Photoelectron Spectroscopy (ARPES). The photon source is an undulator of novel fixed-gap design where longitudinal movement of permanent magnetic arrays controls not only the light polarization (including circular and 0-180 deg rotatable linear polarizations) but also the energy without changing the gap. The beamline optics is based on the well-established scheme of plane grating monochromator (PGM) operating in collimated light. The ultimate resolving power E/dE is above 33000 at 1 keV photon energy. The choice of blazed vs lamellar gratings and optimization of their profile parameters is described. Due to glancing angles on the mirrors as well as optimized groove densities and profiles of the gratings, high photon flux is achieved up to 1.0e13 photons/s/0.01%BW at 1 keV. Ellipsoida...

  13. The secondary maxima in black hole X-ray nova light curves - Clues toward a complete picture

    Science.gov (United States)

    Chen, Wan; Livio, Mario; Gehrels, Neil

    1993-01-01

    We study the secondary maxima observed commonly in the X-ray/optical light curves of black hole X-ray novae and show that they can play an important role in our understanding of the X-ray nova phenomenon. We discuss the observational characteristics of the secondary maxima and possible mechanisms to produce them. We propose a complete scenario for black hole X-ray nova events. The main outburst is caused by a disk instability. The second maximum is caused by X-ray evaporation of the matter near the inner Lagrangian (L1) region when the disk becomes optically thin. The third maximum (or the final minioutburst) is due to a mass transfer instability caused by hard X-ray heating of the subphotospheric layers of the secondary during the outburst. We predict that the newly discovered X-ray nova GRO J0422 + 32 may develop a final minioutburst in early 1993 and that its binary orbital period is less than 7 hr.

  14. Photon-in photon-out hard X-ray spectroscopy at the Linac Coherent Light Source

    International Nuclear Information System (INIS)

    A description of hard X-ray photon-in photon-out spectroscopy techniques for X-ray free electron laser applications is given. A discussion of the instrumentation suitable for taking full advantage of these new sources and a description of recent measurements performed and related examples are also presented. X-ray free-electron lasers (FELs) have opened unprecedented possibilities to study the structure and dynamics of matter at an atomic level and ultra-fast timescale. Many of the techniques routinely used at storage ring facilities are being adapted for experiments conducted at FELs. In order to take full advantage of these new sources several challenges have to be overcome. They are related to the very different source characteristics and its resulting impact on sample delivery, X-ray optics, X-ray detection and data acquisition. Here it is described how photon-in photon-out hard X-ray spectroscopy techniques can be applied to study the electronic structure and its dynamics of transition metal systems with ultra-bright and ultra-short FEL X-ray pulses. In particular, some of the experimental details that are different compared with synchrotron-based setups are discussed and illustrated by recent measurements performed at the Linac Coherent Light Source

  15. A JET BREAK IN THE X-RAY LIGHT CURVE OF SHORT GRB 111020A: IMPLICATIONS FOR ENERGETICS AND RATES

    Energy Technology Data Exchange (ETDEWEB)

    Fong, W.; Berger, E.; Margutti, R.; Zauderer, B. A.; Czekala, I.; Chornock, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Troja, E.; Gehrels, N.; Sakamoto, T. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Fox, D. B. [Department of Astronomy and Astrophysics, 525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802 (United States); Podsiadlowski, P. [Department of Astronomy, Oxford University, Oxford OX1 3RH (United Kingdom)

    2012-09-10

    We present broadband observations of the afterglow and environment of the short GRB 111020A. An extensive X-ray light curve from Swift/XRT, XMM-Newton, and Chandra, spanning {approx}100 s to 10 days after the burst, reveals a significant break at {delta}t Almost-Equal-To 2 days with pre- and post-break decline rates of {alpha}{sub X,1} Almost-Equal-To -0.78 and {alpha}{sub X,2} {approx}< -1.7, respectively. Interpreted as a jet break, we infer a collimated outflow with an opening angle of {theta}{sub j} Almost-Equal-To 3 Degree-Sign -8 Degree-Sign . The resulting beaming-corrected {gamma}-ray (10-1000 keV band) and blast-wave kinetic energies are (2-3) Multiplication-Sign 10{sup 48} erg and (0.3-2) Multiplication-Sign 10{sup 49} erg, respectively, with the range depending on the unknown redshift of the burst. We report a radio afterglow limit of <39 {mu}Jy (3{sigma}) from Expanded Very Large Array observations that, along with our finding that {nu}{sub c} < {nu}{sub X}, constrains the circumburst density to n{sub 0} {approx} 0.01-0.1 cm{sup -3}. Optical observations provide an afterglow limit of i {approx}> 24.4 mag at 18 hr after the burst and reveal a potential host galaxy with i Almost-Equal-To 24.3 mag. The subarcsecond localization from Chandra provides a precise offset of 0.''80 {+-} 0.''11 (1{sigma}) from this galaxy corresponding to an offset of 5-7 kpc for z 0.5-1.5. We find a high excess neutral hydrogen column density of (7.5 {+-} 2.0) Multiplication-Sign 10{sup 21} cm{sup -2} (z = 0). Our observations demonstrate that a growing fraction of short gamma-ray bursts (GRBs) are collimated, which may lead to a true event rate of {approx}> 100-1000 Gpc{sup -3} yr{sup -1}, in good agreement with the NS-NS merger rate of Almost-Equal-To 200-3000 Gpc{sup -3} yr{sup -1}. This consistency is promising for coincident short GRB-gravitational wave searches in the forthcoming era of Advanced LIGO/VIRGO.

  16. Fast Strain Mapping of Nanowire Light-Emitting Diodes Using Nanofocused X-ray Beams.

    Science.gov (United States)

    Stankevič, Tomaš; Hilner, Emelie; Seiboth, Frank; Ciechonski, Rafal; Vescovi, Giuliano; Kryliouk, Olga; Johansson, Ulf; Samuelson, Lars; Wellenreuther, Gerd; Falkenberg, Gerald; Feidenhans'l, Robert; Mikkelsen, Anders

    2015-07-28

    X-ray nanobeams are unique nondestructive probes that allow direct measurements of the nanoscale strain distribution and composition inside the micrometer thick layered structures that are found in most electronic device architectures. However, the method is usually extremely time-consuming, and as a result, data sets are often constrained to a few or even single objects. Here we demonstrate that by special design of a nanofocused X-ray beam diffraction experiment we can (in a single 2D scan with no sample rotation) measure the individual strain and composition profiles of many structures in an array of upright standing nanowires. We make use of the observation that in the generic nanowire device configuration, which is found in high-speed transistors, solar cells, and light-emitting diodes, each wire exhibits very small degrees of random tilts and twists toward the substrate. Although the tilt and twist are very small, they give a new contrast mechanism between different wires. In the present case, we image complex nanowires for nanoLED fabrication and compare to theoretical simulations, demonstrating that this fast method is suitable for real nanostructured devices. PMID:26090689

  17. Evaluating scintillator performance in time-resolved hard X-ray studies at synchrotron light sources.

    Science.gov (United States)

    Rutherford, Michael E; Chapman, David J; White, Thomas G; Drakopoulos, Michael; Rack, Alexander; Eakins, Daniel E

    2016-05-01

    The short pulse duration, small effective source size and high flux of synchrotron radiation is ideally suited for probing a wide range of transient deformation processes in materials under extreme conditions. In this paper, the challenges of high-resolution time-resolved indirect X-ray detection are reviewed in the context of dynamic synchrotron experiments. In particular, the discussion is targeted at two-dimensional integrating detector methods, such as those focused on dynamic radiography and diffraction experiments. The response of a scintillator to periodic synchrotron X-ray excitation is modelled and validated against experimental data collected at the Diamond Light Source (DLS) and European Synchrotron Radiation Facility (ESRF). An upper bound on the dynamic range accessible in a time-resolved experiment for a given bunch separation is calculated for a range of scintillators. New bunch structures are suggested for DLS and ESRF using the highest-performing commercially available crystal LYSO:Ce, allowing time-resolved experiments with an interframe time of 189 ns and a maximum dynamic range of 98 (6.6 bits). PMID:27140147

  18. The nature of very faint X-ray binaries; hints from light curves

    CERN Document Server

    Heinke, C O; Degenaar, N; Wijnands, R

    2014-01-01

    Very faint X-ray binaries (VFXBs), defined as having peak luminosities Lx of 10^34-10^36 erg/s, have been uncovered in significant numbers, but remain poorly understood. We analyse three published outburst light curves of two transient VFXBs using the exponential and linear decay formalism of King and Ritter (1998). The decay timescales and brink luminosities suggest orbital periods of order 1 hour. We review various estimates of VFXB properties, and compare these with suggested explanations of the nature of VFXBs. We suggest that: 1) VFXB outbursts showing linear decays might be explained as partial drainings of the disc of "normal" X-ray transients, and many VFXB outbursts may belong to this category; 2) VFXB outbursts showing exponential decays are best explained by old, short-period systems involving mass transfer from a low-mass white dwarf or brown dwarf; 3) persistent (or quasi-persistent) VFXBs, which maintain an Lx of 10^34-10^35 erg/s for years, may be explained by magnetospheric choking of the accr...

  19. Magnetic measurements of the NSLS [National Synchrotron Light Source] soft x-ray undulator

    International Nuclear Information System (INIS)

    The Soft X-Ray Undulator Magnet was installed in the X-ray Ring (X1 beam line) at the National Synchrotron Light Source at Brookhaven National Laboratory in June 1988. Prior to its installation extensive magnetic measurements were performed at the NSLS Magnetic Measurements Lab in order to determine the operating values for the end corrector currents, the field quality, and the integrated multipoles associated with the magnet as a function of gap. This report is intended to summarize the results of these measurements. The iron poles are 18mm x 32mm x 86mm, and the Samarium Cobalt permanent magnet blocks are 22mm x 21mm x 110mm. In each of the magnet halves there are 76 slots, 70 of which were filled with two magnets per slot, and 6 of which were left empty (3 each on the upstream and downstream ends of the magnet). These slots were left empty in order to approximate an infinitely long magnet in the algorithm for the magnet block sorting. The magnet period is 80mm, and the gap range is 31--100mm, with field values of 3500 and 200 Gauss respectively. For this gap range the undulator parameter K, where K = 0.934 B(Tesla) λ(cm), ranges from 2.6 to 0.15. 14 figs., 5 tabs

  20. Synchrotron X-Ray Microdiffraction Studies of Electromigration in Interconnect lines at the Advanced Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Nobumichi; Chen, Kai; Kunz, Martin

    2009-05-01

    Synchrotron polychromatic X-ray microdiffraction is a particularly suitable technique to study in situ the effect of electromigration in metal interconnects as add spatial resolution to grain orientation and strain sensitivity. This technique has been extensively used at the Advanced Light Source to monitor changes in aluminum and copper interconnect test structures while high-density current is passed into them during accelerated tests at elevated temperature. One of the principal findings is the observation of electromigration-induced plasticity in the metal lines that appear during the very early stages of electromigration. In some of the lines, high density of geometrically necessary dislocation are formed leading to additional diffusion paths causing an enhancement of electromigration effect at test temperature. This paper presents an overview of the principal results obtained from X-ray microdiffraction studies of electromigration effects on aluminum and copper interconnects at the ALS throughout continuous efforts that spanned over a decade (1998-2008) from approximately 40 weeks of combined beamtime.

  1. Synchrotron X-Ray Microdiffraction Studies of Electromigration in Interconnect lines at the Advanced Light Source

    International Nuclear Information System (INIS)

    Synchrotron polychromatic X-ray microdiffraction is a particularly suitable technique to study in situ the effect of electromigration in metal interconnects as add spatial resolution to grain orientation and strain sensitivity. This technique has been extensively used at the Advanced Light Source to monitor changes in aluminum and copper interconnect test structures while high-density current is passed into them during accelerated tests at elevated temperature. One of the principal findings is the observation of electromigration-induced plasticity in the metal lines that appear during the very early stages of electromigration. In some of the lines, high density of geometrically necessary dislocation are formed leading to additional diffusion paths causing an enhancement of electromigration effect at test temperature. This paper presents an overview of the principal results obtained from X-ray microdiffraction studies of electromigration effects on aluminum and copper interconnects at the ALS throughout continuous efforts that spanned over a decade (1998-2008) from approximately 40 weeks of combined beamtime.

  2. ALS-II, a potential soft X-ray, diffraction limited upgrade of the advanced light source

    International Nuclear Information System (INIS)

    The Advanced Light Source (ALS) at Berkeley Lab has seen many upgrades over the years, keeping it one of the brightest sources for soft x-rays worldwide. Recent developments in magnet technology and lattice design appear to open the door for very large further increases in brightness [1], particularly by reducing the horizontal emittance, even within the space constraints of the existing tunnel. Initial studies for possible lattices will be presented that could approach the soft x-ray diffraction limit around 2 keV in both planes within the ALS footprint. Emerging scientific applications and experimental methods that would greatly benefit from ring based sources having much higher brightness and transverse coherence than present or near future storage ring facilities include nanometer imaging applications, X-ray correlation spectroscopy, diffraction microscopy, holography, ptychography, and resonant inelastic soft X-ray scattering at high resolution.

  3. 3D-CT imaging using characteristic X-rays and visible lights produced by ion micro-beam bombardment

    Science.gov (United States)

    Ishii, K.; Matsuyama, S.; Yamazaki, H.; Watanabe, Y.; Kawamura, Y.; Yamaguchi, T.; Momose, G.; Kikuchi, Y.; Terakawa, A.; Galster, W.

    2006-08-01

    We improved the spatial resolution of a 3D-CT imaging system consisting of a micro-beam and an X-ray CCD camera of 1 mega pixels (Hamamatsu photonics C8800X), whose element size is 8 μm × 8 μm providing an image size of 8 mm × 8 mm. A small ant of ∼6 mm body length was placed in a small tube, rotated by a stepping motor, and a spatial resolution of 4 μm for X-ray micron-CT using characteristic Ti-K-X-rays (4.558 keV) produced by 3 MeV proton micro-beams was obtained. We applied the X-ray micron-CT to a small ant's head and obtained the fine structures of the head's interior. Because the CCD is sensitive to visible light, we also examined the capability of light micron-CT using visible red light from an Al2O3(Cr) ruby scintillator and applied the micron-CT to a small red tick. Though the red tick is highly transparent to Ti-K-X-rays, visible red light does not penetrate through the red tick. The most serious problem was dispersion of lights due to Thomson scattering resulting in obscure projection images.

  4. X-ray photoelectron spectroscopy and electron probe X-ray microanalysis investigation and chemical speciation of aerosol samples formed in light water reactor core-melting experiments

    International Nuclear Information System (INIS)

    Aerosol samples consisting of fission products and elements of light water reactor structural materials were collected during laboratory-scale simulation of the heat-up phase of a core melt accident. The aerosol particles were formed in a steam atmosphere at temperatures of the melting charge between 1200 and 19000C. The investigation of the samples by use of x-ray photoelectron spectroscopy (XPS) permitted the chemical speciation of the detected aerosol constituents silver, cadmium, indium, tellurium, iodine, and cesium. A comparison of the elemental analysis results obtained from XPS with those achieved from electron probe x-ray microanalysis revealed that aerosol particle surface and aerosol particle bulk are principally composed of the same elements. The compositions determined in dependence of the release temperature reflect the differing volatilities of the detected elements. Quantitative differences between the composition of surface and bulk have been observed only for those aerosol samples that were collected at higher melting charge temperatures. These samples show an enrichment of more volatile species at the particles' surfaces. In order to obtain direct information on chemical species below the surface, selected samples were argon ion bombarded. Changes in composition and chemistry were monitored by XPS, and the results were interpreted under consideration of possible influences of the sputter process on the surface composition

  5. Demonstration of a time-resolved x-ray scattering instrument utilizing the full-repetition rate of x-ray pulses at the Pohang Light Source

    Science.gov (United States)

    Jo, Wonhyuk; Eom, Intae; Landahl, Eric C.; Lee, Sooheyong; Yu, Chung-Jong

    2016-03-01

    We report on the development of a new experimental instrument for time-resolved x-ray scattering (TRXS) at the Pohang Light Source (PLS-II). It operates with a photon energy ranging from 5 to 18 keV. It is equipped with an amplified Ti:sappahire femtosecond laser, optical diagnostics, and laser beam delivery for pump-probe experiments. A high-speed single-element detector and high trigger-rate oscilloscope are used for rapid data acquisition. While this instrument is capable of measuring sub-nanosecond dynamics using standard laser pump/x-ray probe techniques, it also takes advantage of the dense 500 MHz standard fill pattern in the PLS-II storage ring to efficiently record nano-to-micro-second dynamics simultaneously. We demonstrate this capability by measuring both the (fast) impulsive strain and (slower) thermal recovery dynamics of a crystalline InSb sample following intense ultrafast laser excitation. Exploiting the full repetition rate of the storage ring results in a significant improvement in data collection rates compared to conventional bunch-tagging methods.

  6. Light Dawns on Dark Gamma-ray Bursts

    Science.gov (United States)

    2010-12-01

    Gamma-ray bursts are among the most energetic events in the Universe, but some appear curiously faint in visible light. The biggest study to date of these so-called dark gamma-ray bursts, using the GROND instrument on the 2.2-metre MPG/ESO telescope at La Silla in Chile, has found that these gigantic explosions don't require exotic explanations. Their faintness is now fully explained by a combination of causes, the most important of which is the presence of dust between the Earth and the explosion. Gamma-ray bursts (GRBs), fleeting events that last from less than a second to several minutes, are detected by orbiting observatories that can pick up their high energy radiation. Thirteen years ago, however, astronomers discovered a longer-lasting stream of less energetic radiation coming from these violent outbursts, which can last for weeks or even years after the initial explosion. Astronomers call this the burst's afterglow. While all gamma-ray bursts [1] have afterglows that give off X-rays, only about half of them were found to give off visible light, with the rest remaining mysteriously dark. Some astronomers suspected that these dark afterglows could be examples of a whole new class of gamma-ray bursts, while others thought that they might all be at very great distances. Previous studies had suggested that obscuring dust between the burst and us might also explain why they were so dim. "Studying afterglows is vital to further our understanding of the objects that become gamma-ray bursts and what they tell us about star formation in the early Universe," says the study's lead author Jochen Greiner from the Max-Planck Institute for Extraterrestrial Physics in Garching bei München, Germany. NASA launched the Swift satellite at the end of 2004. From its orbit above the Earth's atmosphere it can detect gamma-ray bursts and immediately relay their positions to other observatories so that the afterglows could be studied. In the new study, astronomers combined Swift

  7. X-Ray Irradiation of H2O + CO Ice Mixtures with Synchrotron Light

    Science.gov (United States)

    Jiménez-Escobar, A.; Chen, Y.-J.; Ciaravella, A.; Huang, C.-H.; Micela, G.; Cecchi-Pestellini, C.

    2016-03-01

    We irradiated a (4:1) mixture of water and carbon monoxide with soft X-rays of energies up to 1.2 keV. The experiments were performed using the spherical grating monochromator beamline at National Synchrotron Radiation Research Center in Taiwan. Both monochromatic (300 and 900 eV) and broader energy fluxes (250-1200 eV) were employed. During the irradiation, the H2O + CO mixture was ionized, excited, and fragmented, producing a number of reactive species. The composition of the ice has been monitored throughout both the irradiation and warm-up phases. We identified several products, which can be related through a plausible chemical reaction scheme. Such chemistry is initiated by the injection of energetic photoelectrons that produce multiple ionization events generating a secondary electron cascade. The results have been discussed in light of a model for protoplanetary disks around young solar-type stars.

  8. Synchrotron X-Ray Microdiffraction Studies of Electromigration in Interconnect lines at the Advanced Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Nobumichi; Chen, Kai; Kunz, Martin

    2009-12-01

    Synchrotron polychromatic X-ray microdiffraction is a particularly suitable technique to study in situ the effect of electromigration in metal interconnects as add spatial resolution to grain orientation and strain sensitivity. This technique has been extensively used at the Advanced Light Source to monitor changes in aluminum and copper interconnect test structures while high-density current is passed into them during accelerated tests at elevated temperature. One of the principal findings is the observation of electromigration-induced plasticity in the metal lines that appear during the very early stages of electromigration. In some of the lines, high density of geometrically necessary dislocation are formed leading to additional diffusion paths causing an enhancement of electromigration effect at test temperature.

  9. Synchrotron Vacuum Ultraviolet Light and Soft X-Ray Radiation Effects on Aluminized Teflon FEP Investigated

    Science.gov (United States)

    Dever, Joyce A.; Townsend, Jacqueline A.; Gaier, James R.; Jalics, Alice I.

    1999-01-01

    Since the Hubble Space Telescope (HST) was deployed in low Earth orbit in April 1990, two servicing missions have been conducted to upgrade its scientific capabilities. Minor cracking of second-surface metalized Teflon FEP (DuPont; fluorinated ethylene propylene) surfaces from multilayer insulation (MLI) was first observed upon close examination of samples with high solar exposure retrieved during the first servicing mission, which was conducted 3.6 years after deployment. During the second HST servicing mission, 6.8 years after deployment, astronaut observations and photographic documentation revealed significant cracks in the Teflon FEP layer of the MLI on both the solar- and anti-solar-facing surfaces of the telescope. NASA Goddard Space Flight Center directed the efforts of the Hubble Space Telescope MLI Failure Review Board, whose goals included identifying the low-Earth-orbit environmental constituent(s) responsible for the cracking and embrittling of Teflon FEP which was observed during the second servicing mission. The NASA Lewis Research Center provided significant support to this effort. Because soft x-ray radiation from solar flares had been considered as a possible cause for the degradation of the mechanical properties of Teflon FEP (ref. 1), the effects of soft xray radiation and vacuum ultraviolet light on Teflon FEP were investigated. In this Lewisled effort, samples of Teflon FEP with a 100-nm layer of vapor-deposited aluminum (VDA) on the backside were exposed to synchrotron radiation of various vacuum ultraviolet and soft x-ray wavelengths between 18 nm (69 eV) and 0.65 nm (1900 eV). Synchrotron radiation exposures were conducted using the National Synchrotron Light Source at Brookhaven National Laboratory. Samples of FEP/VDA were exposed with the FEP surface facing the synchrotron beam. Doses and fluences were compared with those estimated for the 20-yr Hubble Space Telescope mission.

  10. Light from electron avalanches and background rejection in X-ray astronomy

    International Nuclear Information System (INIS)

    A modified version of the parallel plate imaging proportional counter, developed to register images of cosmic x-ray sources in the focal planes of x-ray telescopes, has been constructed to investigate the application of risetime discrimination to the scintillation pulses caused by the electron avalanche process. It is shown that efficient background event rejection (> 90%) is achieved and the application of this system for x-ray astronomy is discussed. (U.K.)

  11. High-resolution soft X-ray beamline ADRESS at the Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies.

    Science.gov (United States)

    Strocov, V N; Schmitt, T; Flechsig, U; Schmidt, T; Imhof, A; Chen, Q; Raabe, J; Betemps, R; Zimoch, D; Krempasky, J; Wang, X; Grioni, M; Piazzalunga, A; Patthey, L

    2010-09-01

    The concepts and technical realisation of the high-resolution soft X-ray beamline ADRESS operating in the energy range from 300 to 1600 eV and intended for resonant inelastic X-ray scattering (RIXS) and angle-resolved photoelectron spectroscopy (ARPES) are described. The photon source is an undulator of novel fixed-gap design where longitudinal movement of permanent magnetic arrays controls not only the light polarization (including circular and 0-180 degrees rotatable linear polarizations) but also the energy without changing the gap. The beamline optics is based on the well established scheme of plane-grating monochromator operating in collimated light. The ultimate resolving power E/DeltaE is above 33000 at 1 keV photon energy. The choice of blazed versus lamellar gratings and optimization of their profile parameters is described. Owing to glancing angles on the mirrors as well as optimized groove densities and profiles of the gratings, the beamline is capable of delivering high photon flux up to 1 x 10(13) photons s(-1) (0.01% BW)(-1) at 1 keV. Ellipsoidal refocusing optics used for the RIXS endstation demagnifies the vertical spot size down to 4 microm, which allows slitless operation and thus maximal transmission of the high-resolution RIXS spectrometer delivering E/DeltaE > 11000 at 1 keV photon energy. Apart from the beamline optics, an overview of the control system is given, the diagnostics and software tools are described, and strategies used for the optical alignment are discussed. An introduction to the concepts and instrumental realisation of the ARPES and RIXS endstations is given. PMID:20724785

  12. A setup for resonant inelastic soft x-ray scattering on liquids at free electron laser light sources

    International Nuclear Information System (INIS)

    We present a flexible and compact experimental setup that combines an in vacuum liquid jet with an x-ray emission spectrometer to enable static and femtosecond time-resolved resonant inelastic soft x-ray scattering (RIXS) measurements from liquids at free electron laser (FEL) light sources. We demonstrate the feasibility of this type of experiments with the measurements performed at the Linac Coherent Light Source FEL facility. At the FEL we observed changes in the RIXS spectra at high peak fluences which currently sets a limit to maximum attainable count rate at FELs. The setup presented here opens up new possibilities to study the structure and dynamics in liquids.

  13. Effect of burst and recombination models for Monte Carlo transport of interacting carriers in a-Se x-ray detectors on Swank noise

    International Nuclear Information System (INIS)

    Purpose: The authors describe the modification to a previously developed Monte Carlo model of semiconductor direct x-ray detector required for studying the effect of burst and recombination algorithms on detector performance. This work provides insight into the effect of different charge generation models for a-Se detectors on Swank noise and recombination fraction. Methods: The proposed burst and recombination models are implemented in the Monte Carlo simulation package, ARTEMIS, developed byFang et al. [“Spatiotemporal Monte Carlo transport methods in x-ray semiconductor detectors: Application to pulse-height spectroscopy in a-Se,” Med. Phys. 39(1), 308–319 (2012)]. The burst model generates a cloud of electron-hole pairs based on electron velocity, energy deposition, and material parameters distributed within a spherical uniform volume (SUV) or on a spherical surface area (SSA). A simple first-hit (FH) and a more detailed but computationally expensive nearest-neighbor (NN) recombination algorithms are also described and compared. Results: Simulated recombination fractions for a single electron-hole pair show good agreement with Onsager model for a wide range of electric field, thermalization distance, and temperature. The recombination fraction and Swank noise exhibit a dependence on the burst model for generation of many electron-hole pairs from a single x ray. The Swank noise decreased for the SSA compared to the SUV model at 4 V/μm, while the recombination fraction decreased for SSA compared to the SUV model at 30 V/μm. The NN and FH recombination results were comparable. Conclusions: Results obtained with the ARTEMIS Monte Carlo transport model incorporating drift and diffusion are validated with the Onsager model for a single electron-hole pair as a function of electric field, thermalization distance, and temperature. For x-ray interactions, the authors demonstrate that the choice of burst model can affect the simulation results for the generation

  14. New Directions in X-Ray Light Sources or Fiat Lux: what's under the dome and watching atoms with x-rays (LBNL Summer Lecture Series)

    Energy Technology Data Exchange (ETDEWEB)

    Falcone, Roger

    2008-07-15

    Summer Lecture Series 2008: Molecular movies of chemical reactions and material phase transformations need a strobe of x-rays, the penetrating light that reveals how atoms and molecules assemble in chemical and biological systems and complex materials. Roger Falcone, Director of the Advanced Light Source,will discuss a new generation of x ray sources that will enable a new science of atomic dynamics on ultrafast timescales.

  15. DEVELOPMENTS IN SYNCHROTRON X-RAY COMPUTED MICROTOMOGRAPHY AT THE NATIONAL SYNCHROTRON LIGHT SOURCE.

    Energy Technology Data Exchange (ETDEWEB)

    DOWD,B.A.

    1999-07-23

    Last year, the X27A beamline at the National Synchrotron Light Source (NSLS) became dedicated solely to X-Ray Computed Microtomography (XCMT). This is a third-generation instrument capable of producing tomographic volumes of 1-2 micron resolution over a 2-3mm field of view. Recent enhancements will be discussed. These have focused on two issues: the desire for real-time data acquisition and processing and the need for highly monochromatic beam (.1 % energy bandpass). The latter will permit k-edge subtraction studies and will provide improved image contrast from below the Cr (6 keV) up to the Cs (36 keV) k-edge. A range of applications that benefit from these improvements will be discussed as well. These two goals are somewhat counterproductive, however; higher monochromaticity yields a lower flux forcing longer data acquisition times. To balance the two, a more efficient scintillator for X-ray conversion is being developed. Some testing of a prototype scintillator has been performed; preliminary results will be presented here. In the meantime, data reconstruction times have been reduced, and the entire tomographic acquisition, reconstruction and volume rendering process streamlined to make efficient use of synchrotron beam time. A Fast Filtered Back Transform (FFBT) reconstruction program recently developed helped to reduce the time to reconstruct a volume of 150 x 150 x 250 pixels{sup 3} (over 5 million voxels) from the raw camera data to 1.5 minutes on a dual R10,000 CPU. With these improvements, one can now obtain a ''quick look'' of a small tomographic volume ({approximately}10{sup 6}voxels) in just over 15 minutes from the start of data acquisition.

  16. A compact SR light source for x-ray lithography 'AURORA'

    International Nuclear Information System (INIS)

    A compact synchrotron radiation (SR) light source called AURORA has been developed for industrial use. It is specially designed for X-ray lithography. AURORA consists of a storage ring, injector microtron and SR light beam lines. The storage ring is a superconducting single magnet machine, designed to accelerate a 150 MeV electron beam to 650 MeV and to store as high as 300 mA current. The injector is a racetrack microtron (RTM) producing a pulsed 150 MeV beam. As many as 16 SR light beam channels are available for AURORA. Prototypes of the storage ring and RTM are constructed, and beam commissioning is performed. A hundred and fifty MeV electron beam of a pulsed current 10 μA from the RTM is successfully injected to the ring and accelerated to 600 MeV and 10 mA current stored with a lifetime of more than 20 hours. The half-integer method investigated is shown to work well with the injection efficiency being found to be very high. Improvement of the design is now under way. (N.K.)

  17. LIGHT SOURCE: Spot size diagnostics for flash radiographic X-ray sources at LAPA

    Science.gov (United States)

    Li, Cheng-Gang; Li, Qin; Shi, Jin-Shui; Deng, Jian-Jun

    2009-06-01

    Spot size is one of the parameters to characterize the performance of a radiographic X-ray source. It determines the degree of blurring due to magnification directly. In recent years, a variety of measurement methods have been used to diagnose X-ray spot size at Laboratory of Accelerator Physics and Application (LAPA). Computer simulations and experiments showed that using a rolled-edge to measure the spot size are more accurate, and the intensity distribution of X-ray source was obtained by a device with a square aperture. Experimental and simulation results on a flash X-ray source at our laboratory are presented and discussed in this paper. In addition, a new method for time resolved diagnostics of X-ray spot size is introduced too.

  18. Synthesis, X-ray Structure, Optical, and Electrochemical Properties of a White-Light-Emitting Molecule

    Directory of Open Access Journals (Sweden)

    Jiun-Wei Hu

    2016-01-01

    Full Text Available A new white-light-emitting molecule (1 was synthesized and characterized by NMR spectroscopy, high resolution mass spectrometry, and single-crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic space group Pnma, with a = 12.6814(6, b = 7.0824(4, c = 17.4628(9 Å, α = 90°, β = 90°, γ = 90°. In the crystal, molecules are linked by weak intermolecular C-H···O hydrogen bonds, forming an infinite chain along [100], generating a C(10 motif. Compound 1 possesses an intramolecular six-membered-ring hydrogen bond, from which excited-state intramolecular proton transfer (ESIPT takes place from the phenolic proton to the carbonyl oxygen, resulting in a tautomer that is in equilibrium with the normal species, exhibiting a dual emission that covers almost all of the visible spectrum and consequently generates white light. It exhibits one irreversible one-electron oxidation and two irreversible one-electron reductions in dichloromethane at modest potentials. Furthermore, the geometric structures, frontier molecular orbitals (MOs, and the potential energy curves (PECs for 1 in the ground and the first singlet excited state were fully rationalized by density functional theory (DFT and time-dependent DFT calculations. The results demonstrate that the forward and backward ESIPT may happen on a similar timescale, enabling the excited-state equilibrium to be established.

  19. X-ray spectroscopy of light kaonic atoms – new results and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Marton, J. [Stefan-Meyer-Institut für subatomare Physik, Boltzmanngasse 3, 1090 Wien (Austria); Bazzi, M. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); Beer, G. [Dep. of Physics and Astronomy, University of Victoria, P.O.Box 3055, Victoria B.C. Canada V8W3P6 (Canada); Berucci, C. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); Bombelli, L. [Politecnico di Milano, Dip. di Elettronica e Informazione, Piazza L. da Vinci, 32 I-20133 Milano (Italy); Bragadireanu, A.M. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); IFIN-HH, P.O. box MG-6, R76900 Magurele, Bucharest (Romania); Cargnelli, M. [Stefan-Meyer-Institut für subatomare Physik, Boltzmanngasse 3, 1090 Wien (Austria); Curceanu, C. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); D' Uffizi, A.; Fiorini, C.; Frizzi, T. [Politecnico di Milano, Dip. di Elettronica e Informazione, Piazza L. da Vinci, 32 I-20133 Milano (Italy); Ghio, F. [INFN Sez. di Roma I and Instituto Superiore di Sanita I-00161, Roma (Italy); Guaraldo, C. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); Hayano, R. [University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo (Japan); Iliescu, M. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); Ishiwatari, T. [Stefan-Meyer-Institut für subatomare Physik, Boltzmanngasse 3, 1090 Wien (Austria); Iwasaki, M. [RIKEN, Institute of Physical and Chemical Research, Saitama (Japan); and others

    2012-12-15

    The antikaon interaction on nucleons and nuclei in the low-energy regime is neither simple nor well understood. Rather direct access to this field is provided by x-ray spectroscopy of light kaonic atoms like kaonic hydrogen, deuterium and helium isotopes. A series of precision measurements on kaonic atoms was performed very successfully by the SIDDHARTA Collaboration at the DAΦNE electron-positron collider at LNF-INFN (Frascati, Italy). Consequently, new precision data on the strong interaction observables (i.e. energy shift and broadening of low-lying atomic states) were delivered having an important impact on the theory of low-energy QCD with strangeness. Presently, the follow-up experiment, SIDDHARTA-2, is in preparation, aiming at a determination of the strong interaction observables in kaonic deuterium as the highest priority; other type of measurements (light and heavier kaonic atoms) are as well foreseen. With the kaonic deuterium data the antikaon-nucleon isospin-resolved scattering lengths can be extracted for the first time. An overview of the progress and present status of experimental studies and an outlook to future perspectives in this fascinating research field is given.

  20. Improved micro x-ray fluorescence spectrometer for light element analysis

    International Nuclear Information System (INIS)

    Since most available micro x-ray fluorescence (micro-XRF) spectrometers operate in air, which does not allow the analysis of low-Z elements (Z≤14), a special micro-XRF spectrometer has been designed to extend the analytical range down to light elements (Z≥6). It offers improved excitation and detection conditions necessary for light element analysis. To eliminate absorption of the exciting and fluorescent radiation, the system operates under vacuum condition. Sample mapping is automated and controlled by specialized computer software developed for this spectrometer. Several different samples were measured to test and characterize the spectrometer. The spot size has been determined by scans across a 10 μm Cu wire which resulted in a full width at half maximum of 31 μm for Mo Kα line (17.44 keV) and 44 μm effective beam size for the Cu K edge and 71 μm effective beam size for the Cu L edge. Lower limits of detection in the picogram range for each spot (or μg/cm2) were obtained by measuring various thin metal foils under different conditions. Furthermore, detection limits in the parts per million range were found measuring NIST621 standard reference material. Area scans of a microscopic laser print and NaF droplet were performed to show mapping capabilities.

  1. Discovery of a Black Hole Mass-Period Correlation in Soft X-Ray Transients and Its Implication for Gamma-Ray Burst and Hypernova Mechanisms

    OpenAIRE

    Lee, C.H.; Brown, G. E.; Wijers, R.A.M.J.

    2002-01-01

    We investigate the soft X-ray transients with black hole primaries which may have been the sources of gamma-ray bursts and hypernovae earlier in their evolution. We find that the black-hole mass increases with the orbital period of the binary, both for systems with main-sequence donors and for those with evolved donors. This correlation can be understood in terms of angular-momentum support in the helium star progenitor of the black hole, if the systems with shorter periods had more rapidly r...

  2. Study on Brazil law type twinning in amethyst from Bahia (Brazil) by the X-ray topography and polarized light

    International Nuclear Information System (INIS)

    Brazil law type twinning is very common in quartz. Generally is not observed in normal petrographic thin section but it is possible to study this kind of twinning under polarized light in thicker sections. X-ray topography will be another powerfull method to study and it was applied for the amethytst of the Mina Cabeluda of the state of Bahia. (author)

  3. X-ray Fresnel diffractometry for micron light source size measurement of ultralow-emittance next-generation storage ring

    International Nuclear Information System (INIS)

    A novel emittance diagnostics technique with high sensitivity using X-ray Fresnel diffraction by a single slit has been developed to measure micron-order electron beam sizes at insertion devices (IDs) of photon beamlines. The X-ray Fresnel diffractometry (XFD) is promising for diagnostics of next-generation light sources, where a tuning of ultra-low emittance at IDs is essentially important to ensure the absence of degradation of brilliance and transverse coherence of radiation at beamlines due to distortion of lattice functions. The validity of the new method was theoretically and experimentally studied at SPring-8. The achievable resolution of XFD is also discussed. (author)

  4. Application of light-initiated explosive for simulating x-ray blowoff impulse effects on a full scale reentry vehicle

    International Nuclear Information System (INIS)

    Laboratory nuclear effects testing allows the study of reentry vehicle response to simulated exoatmospheric x-ray encounters. Light-initiated explosive produces the nearly simultaneous impulse loading of a structure by using a spray painted coating of explosive which is detonated by an intense flash of light. A lateral impulse test on a full scale reentry vehicle is described which demonstrates that the light-initiated explosive technique can be extended to the lateral loading of very large systems involving load discontinuities. This experiment required the development of a diagnostic method for verifying the applied impulse, and development of a large light source for simultaneously initiating the explosive over the surface of the vehicle. Acceptable comparison between measured strain response and code predictions is obtained. The structural capability and internal response of a vehicle subjected to an x-ray environment was determined from a light-initiated explosive test

  5. Instrumentation of x-ray diffraction and materials research on the National Synchrotron Light Source. Final report

    International Nuclear Information System (INIS)

    MATRIX was organized in 1980 to formulate a research team to design and construct a beam line at NSLS for x-ray diffraction studies of materials. A versatile system was designed to allow a full range of experimental capabilities for wide angle x-ray scattering experiments including surface diffraction studies. The design and construction of the system has been completed. Testing of parts of the system was completed at CHESS and with x-ray sources or other equipment at member institutions. Installation of the beam line at NSLS is in progress and will proceed in parallel with the commissioning of the x-ray ring at NSLS. Full operation of the beam line is expected to be ready by December 1, 1984 being limited only by the source power of NSLS at that time. Useful experiments could be started if the power is at least 2 GeV and 100ma. The MATRIX beam line was one of the first x-ray beam lines to see light in the beam line in early spring of 1984. In July of 1984, the MATRIX beam line as the first port at NSLS to have a monochromatic beam and to scan part of the spectrum from the source. As part of this contract, six publications have resulted from the various projects. Three publications are concerned directly with the beam line and/or its operation while the other three publications are the result of research associated with the project

  6. All-diamond optical assemblies for a beam-multiplexing X-ray monochromator at the Linac Coherent Light Source

    CERN Document Server

    Stoupin, S; Blank, V D; Shvyd'ko, Yu V; Goetze, K; Assoufid, L; Polyakov, S N; Kuznetsov, M S; Kornilov, N V; Katsoudas, J; Alonso-Mori, R; Chollet, M; Feng, Y; Glownia, J M; Lemke, H; Robert, A; Song, S; Sikorski, M; Zhu, D

    2014-01-01

    A double-crystal diamond (111) monochromator recently implemented at the Linac Coherent Light Source (LCLS) enables splitting of the primary X-ray beam into a pink (transmitted) and a monochromatic (reflected) branch. The first monochromator crystal with a thickness of 100 um provides sufficient X-ray transmittance to enable simultaneous operation of two beamlines. Here we report on the design, fabrication, and X-ray characterization of the first and second (300-um-thick) crystals utilized in the monochromator and the optical assemblies holding these crystals. Each crystal plate has a region of about 5 X 2 mm2 with low defect concentration, sufficient for use in X-ray optics at the LCLS. The optical assemblies holding the crystals were designed to provide mounting on a rigid substrate and to minimize mounting-induced crystal strain. The induced strain was evaluated using double-crystal X-ray topography and was found to be small over the 5 X 2 mm2 working regions of the crystals.

  7. Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source

    Science.gov (United States)

    Munke, Anna; Andreasson, Jakob; Aquila, Andrew; Awel, Salah; Ayyer, Kartik; Barty, Anton; Bean, Richard J.; Berntsen, Peter; Bielecki, Johan; Boutet, Sébastien; Bucher, Maximilian; Chapman, Henry N.; Daurer, Benedikt J.; DeMirci, Hasan; Elser, Veit; Fromme, Petra; Hajdu, Janos; Hantke, Max F.; Higashiura, Akifumi; Hogue, Brenda G.; Hosseinizadeh, Ahmad; Kim, Yoonhee; Kirian, Richard A.; Reddy, Hemanth K.N.; Lan, Ti-Yen; Larsson, Daniel S.D.; Liu, Haiguang; Loh, N. Duane; Maia, Filipe R.N.C.; Mancuso, Adrian P.; Mühlig, Kerstin; Nakagawa, Atsushi; Nam, Daewoong; Nelson, Garrett; Nettelblad, Carl; Okamoto, Kenta; Ourmazd, Abbas; Rose, Max; van der Schot, Gijs; Schwander, Peter; Seibert, M. Marvin; Sellberg, Jonas A.; Sierra, Raymond G.; Song, Changyong; Svenda, Martin; Timneanu, Nicusor; Vartanyants, Ivan A.; Westphal, Daniel; Wiedorn, Max O.; Williams, Garth J.; Xavier, Paulraj Lourdu; Yoon, Chun Hong; Zook, James

    2016-01-01

    Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a well-characterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 μm diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 Ångström were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here. PMID:27478984

  8. A new bend magnet beam line for scanning transmission x-ray microscopy at the Advanced Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Warwick, Tony; Ade, Harald; Kilcoyne, A.L. David; Kritscher, Michael; Tylisczcak, Tolek; Fakra, Sirine; Hitchcock, Adam P.; Hitchcock, Peter; Padmore, Howard A.

    2001-12-12

    The high brightness of the bend magnets at the Advanced Light Source has been exploited to illuminate a Scanning Transmission X-ray Microscope (STXM). This is the first diffraction-limited scanning x-ray microscope to operate with useful count rate on a synchrotron bend magnet source. A simple, dedicated beam line has been built covering the range of photon energy from 250 eV to 600 eV. Ease of use and operational availability are radically improved compared to previous installations using undulator beams. This facility provides radiation for C 1s, N 1s and O 1s near edge x-ray absorption spectro-microscopy with a spectral resolution up to about 1:5000 and with STXM count rates in excess of 1 MHz.

  9. LIGHT SOURCE: A simulation study of Tsinghua Thomson scattering X-ray source

    Science.gov (United States)

    Tang, Chuan-Xiang; Li, Ren-Kai; Huang, Wen-Hui; Chen, Huai-Bi; Du, Ying-Chao; Du, Qiang; Du, Tai-Bin; He, Xiao-Zhong; Hua, Jian-Fei; Lin, Yu-Zhen; Qian, Hou-Jun; Shi, Jia-Ru; Xiang, Dao; Yan, Li-Xin; Yu, Pei-Cheng

    2009-06-01

    Thomson scattering X-ray sources are compact and affordable facilities that produce short duration, high brightness X-ray pulses enabling new experimental capacities in ultra-fast science studies, and also medical and industrial applications. Such a facility has been built at the Accelerator Laboratory of Tsinghua University, and upgrade is in progress. In this paper, we present a proposed layout of the upgrade with design parameters by simulation, aiming at high X-ray pulses flux and brightness, and also enabling advanced dynamics studies and applications of the electron beam. Design and construction status of main subsystems are also presented.

  10. Mass and radius determination for the neutron star in X-ray burst source 4U/MXB 1728-34

    CERN Document Server

    Majczyna, A

    2006-01-01

    We analyzed archival X-ray spectra of MXB 1728-34 obtained in 1996-99 by the Proportional Counter Array on board of the RXTE satellite. X-ray spectra were fitted to our extensive grids of model atmosphere spectra to determine the effective temperature T_eff on the neutron star surface, logarithm of surface gravity log(g), and the gravitational redshift z simultaneously. We have chosen fitting by numerical model spectra plus broad Gaussian line, modified by interstellar absorption and the absorption on dust. We arbitrarily assumed either hydrogen-helium chemical composition of a model atmosphere, or H-He-Fe mixture in solar proportion. The statistically best values of log(g), and z subsequently were used to determine mass and radius of the neutron star. We obtained the best values of the parameters for the neutron star in X-ray burst source MXB 1728-34: mass either M=0.40 or 0.63 M_sol (for H-He or H-He-Fe models, respectively), radius R=4.6 or 5.3 km, log(g)=14.6 or 14.6 and the gravitational redshift z=0.14 ...

  11. Effects of 2'-chlorothymidine on Chinese hamster cells irradiated with x-rays and ultraviolet light

    International Nuclear Information System (INIS)

    Effects of 2'-chlorothymidine (2'-Cl-TdR) and its mother compound, thymidine (TdR), on cell killing induced by X- and UV-irradiation have been investigated. Chinse hamster V-79 (TK+) cells as well as thymidine kinase deficient (TK-) variant cells, which were isolated from parental V-79 cells following stepwise treatment with BUdR, were incubated in a medium containing 2'-Cl-TdR and TdR after X- and UV-irradiation. In the TK+ cells, both 2'-Cl-TdR and TdR enhanced the killing efficiency of X-rays and ultraviolet light. On the other hand, in the TK- cells, only 2'-Cl-TdR enhanced the killing efficiency of X- and UV-irradiation, and no effect of TdR was observed. These results suggest that phosphorylation of TdR by the enzyme is essential for its ability to modify radiation response, while the enhancement of cell killing by 2'-Cl-TdR must be explained by a mechanism at least partly independent of phosphorylation. (author)

  12. Studying nanomagnets and magnetic heterostructures with X-ray PEEM at the Swiss Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Le Guyader, Loiec; Kleibert, Armin [Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Fraile Rodriguez, Arantxa [Departament de Fisica Fonamental and Institut de Nanociencia i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028 Barcelona (Spain); El Moussaoui, Souliman; Balan, Ana; Buzzi, Michele; Raabe, Joerg [Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Nolting, Frithjof, E-mail: frithjof.nolting@psi.ch [Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Time resolved PEEM set up using a femtosecond laser as the pump pulse. Black-Right-Pointing-Pointer Magnetization vectometry based on advanced computer algorithms enables the determination of the in-plane and out-of-plane magnetization directions in micro and nanostructures. Black-Right-Pointing-Pointer Special sample holders allow measurements in applied magnetic fields to study the hysteresis loop of nanoparticles and to image in up to 40 mT out-of-plane magnetic fields. -- Abstract: Polarization dependent X-ray absorption spectroscopy and microscopy enables the element selective investigation of magnetic systems at the nanoscale. At the Swiss Light Source a photoemission electron microscope is used for the study of a broad variety of systems. Here, a review of recent activities is presented with a focus on instrumental and analytical developments. A new procedure for the 3 dimensional determination of the magnetization vector has been developed, and is demonstrated for GdFeCo microstructures displaying in-plane and out-of-plane domains, and sub-20 nm Fe nanoparticles. The recent progress for measurements in applied magnetic fields is presented and a new set-up for time-resolved measurements employing femtosecond laser pulses is described.

  13. A New Relationship Between Soft X-Rays and EUV Flare Light Curves

    Science.gov (United States)

    Thiemann, Edward

    2016-05-01

    Solar flares are the result of magnetic reconnection in the solar corona which converts magnetic energy into kinetic energy resulting in the rapid heating of solar plasma. As this plasma cools, it emits radiation at different EUV wavelengths when the dropping temperature passes a line’s temperature of formation. This results in a delay in the emissions from cooler EUV lines relative to hotter EUV lines. Therefore, characterizing how this hot plasma cools is important for understanding how the corresponding geo-effective extreme ultraviolet (EUV) irradiance evolves in time. I present a simple new framework in which to study flare cooling by using a Lumped Element Thermal Model (LETM). LETM is frequently used in science and engineering to simplify a complex multi-dimensional thermal system by reducing it to a 0-D thermal circuit. For example, a structure that conducts heat out of a system is simplified with a resistive element and a structure that allows a system to store heat is simplified with a capacitive element. A major advantage of LETM is that the specific geometry of a system can be ignored, allowing for an intuitive analysis of the major thermal processes. I show that LETM is able to accurately reproduce the temporal evolution of cooler flare emission lines based on hotter emission line evolution. In particular, it can be used to predict the evolution of EUV flare light curves using the NOAA X-Ray Sensor (XRS).

  14. Studying nanomagnets and magnetic heterostructures with X-ray PEEM at the Swiss Light Source

    International Nuclear Information System (INIS)

    Highlights: ► Time resolved PEEM set up using a femtosecond laser as the pump pulse. ► Magnetization vectometry based on advanced computer algorithms enables the determination of the in-plane and out-of-plane magnetization directions in micro and nanostructures. ► Special sample holders allow measurements in applied magnetic fields to study the hysteresis loop of nanoparticles and to image in up to 40 mT out-of-plane magnetic fields. -- Abstract: Polarization dependent X-ray absorption spectroscopy and microscopy enables the element selective investigation of magnetic systems at the nanoscale. At the Swiss Light Source a photoemission electron microscope is used for the study of a broad variety of systems. Here, a review of recent activities is presented with a focus on instrumental and analytical developments. A new procedure for the 3 dimensional determination of the magnetization vector has been developed, and is demonstrated for GdFeCo microstructures displaying in-plane and out-of-plane domains, and sub-20 nm Fe nanoparticles. The recent progress for measurements in applied magnetic fields is presented and a new set-up for time-resolved measurements employing femtosecond laser pulses is described.

  15. A statistical correlation of sunquakes based on their seismic, white light, and X-ray emission

    CERN Document Server

    Buitrago-Casas, J C; Lindsey, C; Calvo-Mozo, B; Krucker, S; Glesener, L; Zharkov, S

    2015-01-01

    Several mechanisms have been proposed to explain the transient seis- mic emission, i.e., sunquakes, from some solar flares. Some theories associate high-energy electrons and/or white-light emission with sunquakes. High-energy charged particles and their subsequent heating of the photosphere and/or chro- mosphere could induce acoustic waves in the solar interior. We carried out a correlative study of solar flares with emission in hard-X rays (HXRs), enhanced continuum emission at 6173{\\AA}, and transient seismic emission. We selected those flares observed by RHESSI (Reuven Ramaty High Energy Solar Spectroscopic Imager) with a considerable flux above 50 keV between January 1, 2010 and June 26, 2014. We then used data from the Helioseismic and Magnetic Imager onboard the Solar Dynamic Observatory (SDO/HMI) to search for excess visible continuum emission and new sunquakes not previously reported. We found a total of 18 sunquakes out of 75 investigated. All of the sunquakes were associated with a enhancement of th...

  16. Initial feasibility study of a dedicated synchrotron radiation light source for ultrafast X-ray science

    International Nuclear Information System (INIS)

    We present an initial feasibility summary of a femtosecond synchrotron radiation x-ray source based on a flat-beam rf gun and a recirculating superconducting linac that provides beam to an array of undulators and bend magnets. Optical pulse durations of < 100 fs are obtained by a combination of electron pulse compression, transverse temporal correlation of the electrons, and x-ray pulse compression. After an introduction and initial scientific motivation, we cover the following aspects of the design: layout and lattice, ultra-fast x-ray pulse production, flat electron-beam production, the rf gun, rf systems, cryogenic systems, collective effects, photon production, and synchronization of x-ray and laser pulses. We conclude with a summary of issues and areas of development that remain to be addressed

  17. The Soft X-ray Research instrument at the Linac Coherent Light Source

    Science.gov (United States)

    Dakovski, Georgi L.; Heimann, Philip; Holmes, Michael; Krupin, Oleg; Minitti, Michael P.; Mitra, Ankush; Moeller, Stefan; Rowen, Michael; Schlotter, William F.; Turner, Joshua J.

    2015-01-01

    The Soft X-ray Research instrument provides intense ultrashort X-ray pulses in the energy range 280–2000 eV. A diverse set of experimental stations may be installed to investigate a broad range of scientific topics such as ultrafast chemistry, highly correlated materials, magnetism, surface science, and matter under extreme conditions. A brief description of the main instrument components will be given, followed by some selected scientific highlights. PMID:25931059

  18. The Coherent X-ray Imaging instrument at the Linac Coherent Light Source

    Science.gov (United States)

    Liang, Mengning; Williams, Garth J.; Messerschmidt, Marc; Seibert, M. Marvin; Montanez, Paul A.; Hayes, Matt; Milathianaki, Despina; Aquila, Andrew; Hunter, Mark S.; Koglin, Jason E.; Schafer, Donald W.; Guillet, Serge; Busse, Armin; Bergan, Robert; Olson, William; Fox, Kay; Stewart, Nathaniel; Curtis, Robin; Miahnahri, Alireza Alan; Boutet, Sébastien

    2015-01-01

    The Coherent X-ray Imaging (CXI) instrument specializes in hard X-ray, in-vacuum, high power density experiments in all areas of science. Two main sample chambers, one containing a 100 nm focus and one a 1 µm focus, are available, each with multiple diagnostics, sample injection, pump–probe and detector capabilities. The flexibility of CXI has enabled it to host a diverse range of experiments, from biological to extreme matter. PMID:25931062

  19. Precision spectroscopy of light kaonic atom X-rays in the SIDDHARTA experiment

    International Nuclear Information System (INIS)

    The SIDDHARTA experiment successfully measured kaonic atom X-rays using four gas targets of hydrogen, deuterium, helium-3, and helium-4 at the DAΦNH electron-positron collider. Excellent performance of the SDDs under beam conditions was found in terms of X-ray energy resolution and a good background suppression capability. The preliminary results of the strong-interaction shifts of the kaonic atoms with Z = 1 and 2 are given.

  20. On the features of bursts of neutrons, hard x-rays and alpha-particles in the pulse vacuum discharge with a virtual cathode and self-organization

    Science.gov (United States)

    Kurilenkov, Yu K.; Tarakanov, V. P.; Gus'kov, S. Yu; Samoylov, I. S.; Ostashev, V. E.

    2015-11-01

    In this paper, we continue the discussion of the experimental results on the yield of DD neutrons and hard x-rays in the nanosecond vacuum discharge (NVD) with a virtual cathode, which was started in the previous article of this issue, and previously (Kurilenkov Y K et al 2006 J. Phys. A: Math. Gen. 39 4375). We have considered here the regimes of very dense interelectrode aerosol ensembles, in which diffusion of even hard x-rays is found. The yield of DD neutrons in these regimes is conditioned not only by the head-on deuteron-deuteron collisions in the potential well of virtual cathode, but also by the channel of “deuteron-deuterium cluster” reaction, which exceeds overall yield of neutrons per a shot by more than an order of magnitude, bringing it up to ∼ 107/(4π). Very bright bursts of hard x-rays are also represented and discussed here. Presumably, their nature may be associated with the appearance in the NVD of some properties of random laser in the x-ray spectrum. Good preceding agreeing of the experiment on the DD fusion in the NVD with its particle-in-cell (PIC) simulations provides a basis to begin consideration of nuclear burning “proton-boron” in the NVD, which will be accompanied by the release of alpha particles only. With this objective in view, there has been started the PIC-simulation of aneutronic burning of p-B11, and its preliminary results are presented.

  1. The Energetics of Wight-light Flares Observed in Visible Continuum and Hard X-ray

    Science.gov (United States)

    Huang, Nengyi; Xu, Yan; Wang, Haimin

    2016-05-01

    White-light (WL) flares have been observed and studied more than a century since the first discovery. However, some fundamental physics behind the brilliant emission remains highly controversial. One of the important facts in addressing the flare energetics is the spatial-temporal correlation between the white-light emission and the hard X-ray radiation, presumably suggesting that the energetic electrons are the energy sources. In this study, we present a statistical analysis of 26 strong flares (>M5) observed simultaneously by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). Among these events, WL emission was detected by SDO/HMI in 13 flares, associated with HXR emission. To quantitatively describe the strength of WL emission, equivalent area is defined as the integrated contrast enhancement over the entire flaring area. Our results show that the equivalent area is inversely proportional to the HXR power index, indicating that stronger WL emission tends to be associated with larger population of high energy electrons. Furthermore, we studied an M6.6 flare on 2015 June 22 observed by BBSO’s New Solar Telescope (NST), showing WL emission in TiO continuum (705.7 nm), but no detectable WL signal from SDO/HMI. The power index- equivalent area relationship of this flare matches the trend found in the statistical analysis. In addition, for the other group of 13 flares without detectable WL emission, the HXR spectra are softer (larger power index) than those flares with WL emission, especially for the X-class flares in this group.

  2. Lord of the Rings: A Kinematic Distance to Circinus X-1 from a Giant X-Ray Light Echo

    CERN Document Server

    Heinz, Sebastian; Braiding, Catherine; Brandt, William N; Jonker, Peter G; Sell, Paul; Fender, Robert P; Nowak, Michael A; Schulz, Norbert S

    2015-01-01

    Circinus X-1 exhibited a bright X-ray flare in late 2013. Follow-up observations with Chandra and XMM-Newton from 40 to 80 days after the flare reveal a bright X-ray light echo in the form of four well-defined rings with radii from 5 to 13 arcminutes, growing in radius with time. The large fluence of the flare and the large column density of interstellar dust towards Circinus X-1 make this the largest and brightest set of rings from an X-ray light echo observed to date. By deconvolving the radial intensity profile of the echo with the MAXI X-ray lightcurve of the flare we reconstruct the dust distribution towards Circinus X-1 into four distinct dust concentrations. By comparing the peak in scattering intensity with the peak intensity in CO maps of molecular clouds from the Mopra Southern Galactic Plane CO Survey we identify the two innermost rings with clouds at radial velocity ~ -74 km/s and ~ -81 km/s, respectively. We identify a prominent band of foreground photoelectric absorption with a lane of CO gas at...

  3. Light-sensitive elements for radiographic use and process for the formation of an X-ray image

    International Nuclear Information System (INIS)

    A light-sensitive silver halide element for radiographic use with X-ray intensifying screens comprising coated on at least one side of a transparent support base at least a spectrally sensitized silver halide emulsion layer and, between the base and a silver halide emulsion layer, a hydrophillic colloid layer containing a) substantially light-insensitivelow iodide silver bromoiodide grains having an avergae grain size in therange of from 0.01 to 0.1 μm on which a spectral sensitizing dye is adsorbed to form a J-band, said dye adsorbed on said grains having a significant portion of its absorption in a region of the electromagnetic spectrum corresponding substantially to the spectral sensitivity of the silver halide emulsion, and b) dispersed zinc oxide particles. The invention allows the use of low coverage weights of silver halide light-sensitive elements and provides X-ray images with a favorable image quality and sensitivity ratio. (author)

  4. Comparison of simulated light sensitometer and x-ray sensitometer for screen-film system in medical radiology

    Energy Technology Data Exchange (ETDEWEB)

    Tsuyama, Yasuko (Yasuda Fire and Marine Insurance Co. Osaka Clinic (Japan)); Yamamoto, Yoshinori

    1983-11-01

    Sensitometric techniques are used for determining the characteristic curve in medical imaging. In this study intensity-scale (inverse square law, simulated light) methods are used in the determination of radiographic screen-film system characteristic curve. Films which were exposed to simulated light and x-ray were processed in the same automatic processor simultaneously. These curves were overlapped at net density of 1.0 to compare the curve shapes. The results show there is a good correlation between the density of x-ray sensitometry and that of simulated light sensitometry. The differences of density are within +- 0.12 (+- 10 % log exposure). This applies to both blue sensitive and green sensitive systems.

  5. Comparison of simulated light sensitometer and x-ray sensitometer for screen-film system in medical radiology

    International Nuclear Information System (INIS)

    Sensitometric techniques are used for determining the characteristic curve in medical imaging. In this study intensity-scale (inverse square law, simulated light) methods are used in the determination of radiographic screen-film system characteristic curve. Films which were exposed to simulated light and x-ray were processed in the same automatic processor simultaneously. These curves were overlapped at Net density of 1.0 to compare the curve shapes. The results show there is a good correlation between the density of x-ray sensitometry and that of simulated light sensitometry. The differences of density are within +- 0.12 (+- 10 % log exposure). This applies to both blue sensitive and green sensitive systems. (author)

  6. The hard X-ray spectrum of NGC 1365: scattered light, not black hole spin

    CERN Document Server

    Miller, L

    2013-01-01

    Active Galactic Nuclei (AGN) show excess X-ray emission above 10 keV compared with extrapolation of spectra from lower energies. Risaliti et al. have recently attempted to model the hard X-ray excess in the type 1.8 AGN NGC 1365, concluding that the hard excess most likely arises from Compton-scattered reflection of X-rays from an inner accretion disk close to the black hole. Their analysis disfavored a model in which the hard excess arises from a high column density of circumnuclear gas partially covering a primary X-ray source, despite such components being required in the NGC 1365 data below 10 keV. Using a Monte Carlo radiative transfer approach, we demonstrate that this conclusion is invalidated by (i) use of slab absorption models, which have unrealistic transmission spectra for partial covering gas, (ii) neglect of the effect of Compton scattering on transmitted spectra and (iii) inadequate modeling of the expected spectrum of scattered X-rays. The scattered spectrum is geometry dependent and, for high...

  7. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... clothing that might interfere with the x-ray images. Women should always inform their physician and x-ray ... small burst of radiation that passes through the body, recording an image on photographic film or a special detector. Different ...

  8. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... x-ray machine produces a small burst of radiation that passes through the body, recording an image on photographic film or a special detector. Different parts of the body absorb the x- ...

  9. The Height of a White-Light Flare and its Hard X-Ray Sources

    Science.gov (United States)

    Oliveros, Juan-Carlos Martinez; Hudson, Hugh S.; Hurford, Gordon J.; Kriucker, Saem; Lin, R. P.; Lindsey, Charles; Couvidat, Sebastien; Schou, Jesper; Thompson, W. T.

    2012-01-01

    We describe observations of a white-light (WL) flare (SOL2011-02-24T07:35:00, M3.5) close to the limb of the Sun, from which we obtain estimates of the heights of the optical continuum sources and those of the associated hard X-ray (HXR) sources. For this purpose, we use HXR images from the Reuven Ramaty High Energy Spectroscopic Imager and optical images at 6173 Ang. from the Solar Dynamics Observatory.We find that the centroids of the impulsive-phase emissions in WL and HXRs (30 -80 keV) match closely in central distance (angular displacement from Sun center), within uncertainties of order 0".2. This directly implies a common source height for these radiations, strengthening the connection between visible flare continuum formation and the accelerated electrons. We also estimate the absolute heights of these emissions as vertical distances from Sun center. Such a direct estimation has not been done previously, to our knowledge. Using a simultaneous 195 Ang. image from the Solar-Terrestrial RElations Observatory spacecraft to identify the heliographic coordinates of the flare footpoints, we determine mean heights above the photosphere (as normally defined; tau = 1 at 5000 Ang.) of 305 +/- 170 km and 195 +/- 70 km, respectively, for the centroids of the HXR and WL footpoint sources of the flare. These heights are unexpectedly low in the atmosphere, and are consistent with the expected locations of tau = 1 for the 6173 Ang and the approx 40 keV photons observed, respectively.

  10. X-ray diffraction patterns of single crystals implanted with high-energy light ions

    International Nuclear Information System (INIS)

    X-ray diffraction patterns of silicon and gallium arsenide single crystals implanted with high-energy protons and α-particles were studied. A various models of lattice parameter changes were analysed. The agreement between the simulation and experiment proves that the lattice parameter depth-distribution can be assumed to be proportional to vacancy distribution obtained by Monte-Carlo method and from the Biersack-Ziegler theory. Most of the X-ray experiments were performed using synchrotron source of X-ray radiation in particular in the case of back-reflection and transmission section topographic methods. The new method of direct determination of the implanted ion ranges was proposed using synchrotron radiation back-reflection section topography. A number of new interference phenomena was revealed and explained. These interferences are important in the applications of diffraction theory in studying of the real structure of implanted layers. (author)

  11. X-ray measurements at high-power lasers. Relative conversion efficiencies of short pulse laser light into K X-ray radiation in medium to high Z elements

    Science.gov (United States)

    Szabo, C. I.; Indelicato, P.; Gumberidze, A.; Holland, G. E.; Seely, J. F.; Hudson, L. T.; Henins, A.; Audebert, P.; Bastiani-Ceccotti, S.; Tabakhoff, E.; Brambrink, E.

    2009-03-01

    Conversion efficiencies of laser light into K x-ray radiation are used to characterize laser-solid interactions e.g. in measurements with back-lighter targets in Inertial Confinement Fusion research or in ultra short x-ray science where ultra short laser pulses are used to create x-rays for investigation of dynamic processes. In our measurements we observed high energy (few tens of keV) K x-ray radiation of element pairs created upon impact of a 1 ps, 100 J laser pulse on the target surface. The high-energy electrons created in this interaction ionise and excite the target material. We have used high purity alloy foils of Pd and Ag, as well as In and Sn and crystals of CsI and rare earth molybdates as target materials. Both constituents of these targets were simultaneously excited in one shot. The K x-ray radiation was dispersed and detected with the LCS (LULI Crystal Spectrometer), a Cauchois-type cylindrically bent transmission-crystal spectrometer. Measuring ratios in the x-ray spectra permits determination of relative conversion efficiencies for pairs of elements under identical laser-target interaction conditions.

  12. Soft X-ray Tomography and Cryogenic Light Microscopy: The Cool Combination in Cellular Imaging

    OpenAIRE

    McDermott, Gerry; Le Gros, Mark A.; Knoechel, Christian G.; Uchida, Maho; Larabell, Carolyn A.

    2009-01-01

    Soft x-ray tomography (SXT) is ideally suited to imaging sub-cellular architecture and organization, particularly in eukaryotic cells. SXT is similar in concept to the well-established medical diagnostic technique computed axial tomography (CAT), except SXT is capable of imaging with a spatial resolution of 50 nm, or better. In soft x-ray tomography (SXT) cells are imaged using photons from a region of the spectrum known as the ‘water window’. This results in quantitative, high-contrast image...

  13. Light-bending Scenario for Accreting Black Holes in X-ray Polarimetry

    Czech Academy of Sciences Publication Activity Database

    Dovčiak, Michal; Muleri, F.; Goosmann, René; Karas, Vladimír; Matt, G.

    2011-01-01

    Roč. 731, č. 1 (2011), 75/1-75/15. ISSN 0004-637X R&D Projects: GA MŠk(CZ) LC06014; GA ČR GA205/07/0052 Grant ostatní: ESA(XE) ESA-PECS project No.98040 Institutional research plan: CEZ:AV0Z10030501 Keywords : polarization * relativistic processes * X-rays: binaries * X-rays: galaxies Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 6.024, year: 2011

  14. Joint Spectral Analysis for Early Bright X-ray Flares of -Ray Bursts with Swift BAT and XRT Data

    Indian Academy of Sciences (India)

    Fang-Kun Peng; You-Dong Hu; Xiang-Gao Wang; Rui-Jing Lu; En-Wei Liang

    2014-09-01

    A joint spectral analysis for early bright X-ray flares that were simultaneously observed with Swift BAT and XRT are present. Both BAT and XRT lightcurves of these flares are correlated. Our joint spectral analysis shows that the radiations in the two energy bands are from the same spectral component, which can be well fitted with a single power-law. Except for the flares in GRBs 060904B and 100906A, the photon spectral indices are < 2.0, indicating the peak energies (p) of the prompt -rays should be above the high energy end of the BAT band.

  15. Prompt Ultraviolet-to-Soft-X-Ray Emission of Gamma-Ray Bursts: Application to GRB 031203?

    OpenAIRE

    Li, Zhuo; Song, Li-Ming

    2004-01-01

    We discuss the prompt emission of GRBs, allowing for $\\gamma\\gamma$ pair production and synchrotron self-absorption. The observed hard spectra suggest heavy pair-loading in GRBs. The re-emission of the generated pairs results in the energy transmission from high-energy gamma-rays to long-wavelength radiation. Due to strong self-absorption, the synchrotron radiation by pairs is in optically thick regime, showing a thermal-like spectral bump in the extreme-ultraviolet/soft X-ray band, other tha...

  16. INTEGRAL and XMM-Newton observations of the low-luminosity and X-ray-rich burst GRB 040223

    International Nuclear Information System (INIS)

    GRB 040223 was observed by INTEGRAL and XMM-Newton. GRB 040223 has a peak flux of (1.6±0.13) x 10-8 ergs cm-2 s-1, a fluence of (4.4±0.4) x 10-7 ergs cm-2 and a steep photon power law index of -2.3±0.2, in the energy range 20-200 keV. The steep spectrum implies it is an X-ray-rich GRB with emission up to 200 keV and Epeak peak is x = -1.7±0.2, a temporal decay of t-0.75±0.25 and a large column density of 1.8 x 1022 cm-2. The luminosity-lag relationship was used to obtain a redshift z 0.1-0.02+0.04. The isotropic energy radiated in γ-rays and X-ray luminosity after 10 hours are factors of 1000 and 100 less than classical GRBs. GRB 040223 is consistent with the extrapolation of the Amati relation into the region that includes XRF 030723 and XRF 020903

  17. Atomic physics with hard X-rays from high brilliance synchrotron light sources

    Energy Technology Data Exchange (ETDEWEB)

    Southworth, S.; Gemmell, D.

    1996-08-01

    A century after the discovery of x rays, the experimental capability for studying atomic structure and dynamics with hard, bright synchrotron radiation is increasing remarkably. Tempting opportunities arise for experiments on many-body effects, aspects of fundamental photon-atom interaction processes, and relativistic and quantum-electrodynamic phenomena. Some of these possibilities are surveyed in general terms.

  18. Absolute pulse energy measurements of soft x-rays at the Linac Coherent Light Source

    Czech Academy of Sciences Publication Activity Database

    Tiedtke, K.; Sorokin, A. A.; Jastrow, U.; Juranić, P.; Kreis, S.; Gerken, N.; Richter, M.; Arp, U.; Feng, Y.; Nordlund, D.; Soufli, R.; Fernández-Perea, M.; Juha, Libor; Heimann, P.; Nagler, B.; Lee, H.J.; Mack, S.; Cammarata, M.; Krupin, O.; Messerschmidt, M.; Holmes, M.; Rowen, M.; Schlotter, W.; Moeller, S.; Turner, J.J.

    2014-01-01

    Roč. 22, č. 18 (2014), s. 21214-21226. ISSN 1094-4087 R&D Projects: GA MŠk(CZ) LG13029 Institutional support: RVO:68378271 Keywords : soft x-ray * free electron laser * LCLS * instrumentation * measurement * metrology Subject RIV: BH - Optics , Masers, Laser s Impact factor: 3.488, year: 2014

  19. Atomic physics with hard X-rays from high brilliance synchrotron light sources

    International Nuclear Information System (INIS)

    A century after the discovery of x rays, the experimental capability for studying atomic structure and dynamics with hard, bright synchrotron radiation is increasing remarkably. Tempting opportunities arise for experiments on many-body effects, aspects of fundamental photon-atom interaction processes, and relativistic and quantum-electrodynamic phenomena. Some of these possibilities are surveyed in general terms

  20. Using of X-ray apparatus in the light of the new law regulations

    International Nuclear Information System (INIS)

    By passing the new law regulations in the field of radiological protection, the requirements for location and operating rules for X-ray apparatus are intensified significantly. The regulations claim for larger rooms, better ventilation and protection of patients and personnel. (author). 1 ref

  1. Performance of a ruthenium beam separator used to separate soft x rays from light generated by a high-order harmonic light source.

    Science.gov (United States)

    Ichimaru, Satoshi; Hatayama, Masatoshi; Ohchi, Tadayuki; Gullikson, Eric M; Oku, Satoshi

    2016-02-10

    We describe the design and fabrication of a ruthenium beam separator used to simultaneously attenuate infrared light and reflect soft x rays. Measurements in the infrared and soft x-ray regions showed the beam separator to have a reflectivity of 50%-85% in the wavelength region from 6 to 10 nm at a grazing incidence angle of 7.5 deg and 4.3% at 800 nm and the same angle of grazing incidence, indicating that the amount of attenuation is 0.05-0.09. These results show that this beam separator could provide an effective means for separating IR light from soft x rays in light generated by high-order harmonic generation sources. PMID:26906363

  2. Multidimensional modeling of type I X-ray bursts. II. Two-dimensional convection in a mixed H/He accretor

    Energy Technology Data Exchange (ETDEWEB)

    Malone, C. M. [Department of Astronomy and Astrophysics, The University of California Santa Cruz, Santa Cruz, CA 95064 (United States); Zingale, M. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States); Nonaka, A.; Almgren, A. S.; Bell, J. B., E-mail: malone@ucolick.org [Center for Computational Sciences and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2014-06-20

    Type I X-ray bursts are thermonuclear explosions of accreted material on the surface of neutron stars in low-mass X-ray binaries. Prior to the ignition of a subsonic burning front, runaway burning at the base of the accreted layer drives convection that mixes fuel and heavy-element ashes. In this paper, the second in a series, we explore the behavior of this low Mach number convection in mixed hydrogen/helium layers on the surface of a neutron star using two-dimensional simulations with the Maestro code. Maestro takes advantage of the highly subsonic flow field by filtering dynamically unimportant sound waves while retaining local compressibility effects, such as those due to stratification and energy release from nuclear reactions. In these preliminary calculations, we find that the rp-process approximate network creates a convective region that is split into two layers. While this splitting appears artificial due to the approximations of the network regarding nuclear flow out of the breakout reaction {sup 18}Ne(α, p){sup 21}Na, these calculations hint at further simplifications and improvements of the burning treatment for use in subsequent calculations in three dimensions for a future paper.

  3. Multidimensional Modeling of Type I X-ray Bursts. II. Two-Dimensional Convection in a Mixed H/He Accretor

    CERN Document Server

    Malone, C M; Nonaka, A; Almgren, A S; Bell, J B

    2014-01-01

    Type I X-ray Bursts (XRBs) are thermonuclear explosions of accreted material on the surfaces of a neutron stars in low mass X-ray binaries. Prior to the ignition of a subsonic burning front, runaway burning at the base of the accreted layer drives convection that mixes fuel and heavy-element ashes. In this second paper in a series, we explore the behavior of this low Mach number convection in mixed hydrogen/helium layers on the surface of a neutron star using two-dimensional simulations with the Maestro code. Maestro takes advantage of the highly subsonic flow field by filtering dynamically unimportant sound waves while retaining local compressibility effects, such as those due to stratification and energy release from nuclear reactions. In these preliminary calculations, we find that the rp-process approximate network creates a convective region that is split into two layers. While this splitting appears artificial due to the approximations of the network regarding nuclear flow out of the breakout reaction 1...

  4. Systematic Uncertainties in the Spectroscopic Measurements of Neutron-Star Masses and Radii from Thermonuclear X-ray Bursts. III. Absolute Flux Calibration

    CERN Document Server

    Guver, Tolga; Marshall, Herman; Psaltis, Dimitrios; Guainazzi, Matteo; Diaz-Trigo, Maria

    2015-01-01

    Many techniques for measuring neutron star radii rely on absolute flux measurements in the X-rays. As a result, one of the fundamental uncertainties in these spectroscopic measurements arises from the absolute flux calibrations of the detectors being used. Using the stable X-ray burster, GS 1826-238, and its simultaneous observations by Chandra HETG/ACIS-S and RXTE/PCA as well as by XMM-Newton EPIC-pn and RXTE/PCA, we quantify the degree of uncertainty in the flux calibration by assessing the differences between the measured fluxes during bursts. We find that the RXTE/PCA and the Chandra gratings measurements agree with each other within their formal uncertainties, increasing our confidence in these flux measurements. In contrast, XMM-Newton EPIC-pn measures 14.0$\\pm$0.3% less flux than the RXTE/PCA. This is consistent with the previously reported discrepancy with the flux measurements of EPIC-pn, compared to EPIC-MOS1, MOS2 and ACIS-S detectors. We also address the calibration uncertainty in the RXTE/PCA int...

  5. The influence of the energy emitted by solar flare soft X-ray bursts on the propagation of their associated interplanetary shock waves

    Science.gov (United States)

    Pinter, S.; Dryer, M.

    1985-01-01

    The relationship between the thermal energy released from 29 solar flares and the propagation features of their associated interplanetary shock waves that were detected at 1 AU is investigated. The 29 interplanetary shock waves were identified unambiguously and their tracking from each solar flare was deduced by tracking their associated interplanetary type-II radio emission. The thermal energy released in the solar flares was estimated from the time-intensity profiles of 1-8 A soft X-ray bursts from each flare. A good relationship is found between the flares' thermal energy with the IP shock-waves' transient velocity and arrival time at the earth - that is, the largest flare energy released is associated with the faster shock waves. Finally, a possible scenario of formation of a shock wave during the early phase of the flare and its propagation features is discussed.

  6. NuSTAR Observation Of A Type I X-Ray Burst From GRS 1741.9-2853

    DEFF Research Database (Denmark)

    Barriere, Nicolas M.; Krivonos, Roman; Tomsick, John A.;

    2015-01-01

    s-1 in a second observation on 2013 August 3. A bright, 800 s long, H-triggered mixed H/He thermonuclear Type I burst with mild photospheric radius expansion (PRE) was present during the second observation. Assuming that the luminosity during the PRE was at the Eddington level, an H mass fraction X...

  7. 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.

  8. The soft x-ray instrument for materials studies at the linac coherent light source x-ray free-electron laser

    Czech Academy of Sciences Publication Activity Database

    Schlotter, W.F.; Turner, J.J.; Rowen, M.; Heimann, P.; Holmes, M.; Krupin, O.; Messerschmidt, M.; Moeller, S.; Krzywinski, J.; Soufli, R.; Fernández-Perea, M.; Kelez, N.; Lee, S.; Coffee, R.; Hays, G.; Beye, M.; Gerken, N.; Sorgenfrei, F.; Hau-Riege, S.; Juha, Libor; Chalupský, Jaromír; Hájková, Věra; Mancuso, A.P.; Singer, A.; Yefanov, O.; Vartanyants, I.A.; Cadenazzi, G.; Abbey, B.; Nugent, K.A.; Sinn, H.; Lüning, J.; Schaffert, S.; Eisebitt, S.; Lee, W.-S.; Scherz, A.; Nilsson, A.R.; Wurth, W.

    2012-01-01

    Roč. 83, č. 4 (2012), "043107-1"-"043107-11". ISSN 0034-6748 R&D Projects: GA ČR(CZ) GAP108/11/1312 Institutional research plan: CEZ:AV0Z10100523 Keywords : free-electron laser * materials science * beamline * x-ray laser Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.602, year: 2012

  9. Coasting External Shock in Wind Medium: An Origin for the X-Ray Plateau Decay Component in Swift Gamma-Ray Burst Afterglows

    Science.gov (United States)

    Shen, Rongfeng; Matzner, Christopher D.

    2012-01-01

    The plateaus observed in about one half of the early X-ray afterglows are the most puzzling feature in gamma-ray bursts (GRBs) detected by Swift. By analyzing the temporal and spectral indices of a large X-ray plateau sample, we find that 55% can be explained by external, forward shock synchrotron emission produced by a relativistic ejecta coasting in a ρvpropr -2, wind-like medium; no energy injection into the shock is needed. After the ejecta collects enough medium and transitions to the adiabatic, decelerating blast wave phase, it produces the post-plateau decay. For those bursts consistent with this model, we find an upper limit for the initial Lorentz factor of the ejecta, Γ0 <= 46(epsilon e /0.1)-0.24(epsilon B /0.01)0.17; the isotropic equivalent total ejecta energy is E iso ~ 1053(epsilon e /0.1)-1.3(epsilon B /0.01)-0.09(tb /104 s) erg, where epsilon e and epsilon B are the fractions of the total energy at the shock downstream that are carried by electrons and the magnetic field, respectively, and tb is the end of the plateau. Our finding supports Wolf-Rayet stars as the progenitor stars of some GRBs. It raises intriguing questions about the origin of an intermediate-Γ0 ejecta, which we speculate is connected to the GRB jet emergence from its host star. For the remaining 45% of the sample, the post-plateau decline is too rapid to be explained in the coasting-in-wind model, and energy injection appears to be required.

  10. COASTING EXTERNAL SHOCK IN WIND MEDIUM: AN ORIGIN FOR THE X-RAY PLATEAU DECAY COMPONENT IN SWIFT GAMMA-RAY BURST AFTERGLOWS

    International Nuclear Information System (INIS)

    The plateaus observed in about one half of the early X-ray afterglows are the most puzzling feature in gamma-ray bursts (GRBs) detected by Swift. By analyzing the temporal and spectral indices of a large X-ray plateau sample, we find that 55% can be explained by external, forward shock synchrotron emission produced by a relativistic ejecta coasting in a ρ∝r–2, wind-like medium; no energy injection into the shock is needed. After the ejecta collects enough medium and transitions to the adiabatic, decelerating blast wave phase, it produces the post-plateau decay. For those bursts consistent with this model, we find an upper limit for the initial Lorentz factor of the ejecta, Γ0 ≤ 46(εe/0.1)–0.24(εB/0.01)0.17; the isotropic equivalent total ejecta energy is Eiso ∼ 1053(εe/0.1)–1.3(εB/0.01)–0.09(tb /104 s) erg, where εe and εB are the fractions of the total energy at the shock downstream that are carried by electrons and the magnetic field, respectively, and tb is the end of the plateau. Our finding supports Wolf-Rayet stars as the progenitor stars of some GRBs. It raises intriguing questions about the origin of an intermediate-Γ0 ejecta, which we speculate is connected to the GRB jet emergence from its host star. For the remaining 45% of the sample, the post-plateau decline is too rapid to be explained in the coasting-in-wind model, and energy injection appears to be required.

  11. COASTING EXTERNAL SHOCK IN WIND MEDIUM: AN ORIGIN FOR THE X-RAY PLATEAU DECAY COMPONENT IN SWIFT GAMMA-RAY BURST AFTERGLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Shen Rongfeng; Matzner, Christopher D., E-mail: rfshen@astro.utoronto.ca, E-mail: matzner@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, Ontario M5S 3H4 (Canada)

    2012-01-01

    The plateaus observed in about one half of the early X-ray afterglows are the most puzzling feature in gamma-ray bursts (GRBs) detected by Swift. By analyzing the temporal and spectral indices of a large X-ray plateau sample, we find that 55% can be explained by external, forward shock synchrotron emission produced by a relativistic ejecta coasting in a {rho}{proportional_to}r{sup -2}, wind-like medium; no energy injection into the shock is needed. After the ejecta collects enough medium and transitions to the adiabatic, decelerating blast wave phase, it produces the post-plateau decay. For those bursts consistent with this model, we find an upper limit for the initial Lorentz factor of the ejecta, {Gamma}{sub 0} {<=} 46({epsilon}{sub e}/0.1){sup -0.24}({epsilon}{sub B}/0.01){sup 0.17}; the isotropic equivalent total ejecta energy is E{sub iso} {approx} 10{sup 53}({epsilon}{sub e}/0.1){sup -1.3}({epsilon}{sub B}/0.01){sup -0.09}(t{sub b} /10{sup 4} s) erg, where {epsilon}{sub e} and {epsilon}{sub B} are the fractions of the total energy at the shock downstream that are carried by electrons and the magnetic field, respectively, and t{sub b} is the end of the plateau. Our finding supports Wolf-Rayet stars as the progenitor stars of some GRBs. It raises intriguing questions about the origin of an intermediate-{Gamma}{sub 0} ejecta, which we speculate is connected to the GRB jet emergence from its host star. For the remaining 45% of the sample, the post-plateau decline is too rapid to be explained in the coasting-in-wind model, and energy injection appears to be required.

  12. Efficient high-order diffraction of extreme-ultraviolet light and soft x-rays by nanostructured volume gratings.

    Science.gov (United States)

    Hambach, D; Schneider, G; Gullikson, E M

    2001-08-01

    We report what is believed to be the first demonstration that volume gratings diffract extreme-ultraviolet light (EUV) or soft x-rays into high orders approximately an order of magnitude more efficiently than predicted by classical thin-grating theory. At the 13-nm wavelength, copolymer grating structures with 200-nm period and aspect ratios of ~10:1 achieved diffraction efficiencies of 11.2%, 15.3%, 11.5%, and 9.1% in the orders m of 2, 3, 4, and 5, respectively. In addition, the measured transmission spectra are consistent with electrodynamic calculations by coupled-wave theory. High-order diffraction can now be employed for substantially improved diffractive EUV and x-ray optics, e.g., highly resolving diffractive lenses and large-aperture condensers. PMID:18049562

  13. Design of a bolometer for total-energy measurement of the linear coherent light source pulsed X-ray laser

    International Nuclear Information System (INIS)

    We are developing a cryogenic bolometer to measure the total energy of the linear coherent light source (LCLS) free electron X-ray laser to be built at the Stanford Linear Accelerator Center. The laser will produce ultrabright X-ray pulses in the energy range between 0.8 and 8 keV with ∼1012 photons per ∼200 fs pulse at a repeat interval of 8 ms, and will be accompanied by a halo of spontaneous undulator radiation. The bolometer is designed to determine the total energy of each laser pulse to within (1-x)Sr x MnO3 sensor array at the metal-insulator transition, where the composition x is adjusted to produce the desired transition temperature. We discuss design considerations and material choices, and present numerical simulations of the thermal response

  14. Present trends and future perspectives for atomic and molecular physics at the new X-ray light sources

    International Nuclear Information System (INIS)

    The major advances in the actual and predicted performances of new light sources (low-emittance storage rings and soft and hard X-ray free-electron lasers) in the last few years have provided a new impulse to the development of atomic and molecular physics, in particular in what concerns electronic structure and dynamics of atoms, molecules, liquids and clusters investigated with photoelectron spectroscopy, resonant inelastic X-ray scattering and ion spectroscopy. We present here a review on the present trends and future perspectives of the field, with special emphasis on the new possibilities offered by the characteristics of the new sources (high brilliance, low emittance, short pulses). Several examples will be provided concerning state-of-the-art present results and future developments.

  15. The X-ray light curve of the massive colliding wind Wolf-Rayet + O binary WR 21a

    Science.gov (United States)

    Gosset, Eric; Nazé, Yaël

    2016-05-01

    Our dedicated XMM-Newton monitoring, as well as archival Chandra and Swift datasets, were used to examine the behaviour of the WN5h+O3V binary WR 21a at high energies. For most of the orbit, the X-ray emission exhibits few variations. However, an increase in strength of the emission is seen before periastron, following a 1 /D relative trend, where D is the separation between both components. This increase is rapidly followed by a decline due to strong absorption as the Wolf-Rayet (WR) comes in front. The fitted local absorption value appears to be coherent with a mass-loss rate of about 1 × 10-5 M⊙ yr-1 for the WR component. However, absorption is not the only parameter affecting the X-ray emission at periastron as even the hard X-ray emission decreases, suggesting a possible collapse of the colliding wind region near to or onto the photosphere of the companion just before or at periastron. An eclipse may appear as another potential scenario, but it would be in apparent contradiction with several lines of evidence, notably the width of the dip in the X-ray light curve and the absence of variations in the UV light curve. Afterwards, the emission slowly recovers, with a strong hysteresis effect. The observed behaviour is compatible with predictions from general wind-wind collision models although the absorption increase is too shallow. Based on observations collected at ESO as well as with Swift, Chandra, and the ESA science mission XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member States and the USA (NASA).

  16. Correlative cryogenic tomography of cells using light and soft x-rays

    OpenAIRE

    Smith, Elizabeth A.; Cinquin, Bertrand P.; Do, Myan; McDermott, Gerry; Le Gros, Mark A.; Larabell, Carolyn A.

    2013-01-01

    Correlated imaging is the process of imaging a specimen with two complementary modalities, and then combining the two data sets to create a highly informative, composite view. A recent implementation of this concept has been the combination of soft x-ray tomography (SXT) with fluorescence cryogenic microscopy (FCM). SXT-FCM is used to visualize cells that are held in a near-native, cryo-preserved state. The resultant images are, therefore, highly representative of both the cellular architectu...

  17. Toward Control of Matter: Basic Energy Science Needs for a New Class of X-Ray Light Sources

    International Nuclear Information System (INIS)

    Over the past quarter century, light-source user facilities have transformed research in areas ranging from gas-phase chemical dynamics to materials characterization. The ever-improving capabilities of these facilities have revolutionized our ability to study the electronic structure and dynamics of atoms, molecules, and even the most complex new materials, to understand catalytic reactions, to visualize magnetic domains, and to solve protein structures. Yet these outstanding facilities still have limitations well understood by their thousands of users. Accordingly, over the past several years, many proposals and conceptual designs for 'next-generation' x-ray light sources have been developed around the world. In order to survey the scientific problems that might be addressed specifically by those new light sources operating below a photon energy of about 3 keV and to identify the scientific requirements that should drive the design of such facilities, a workshop 'Science for a New Class of Soft X-Ray Light Sources' was held in Berkeley in October 2007. From an analysis of the most compelling scientific questions that could be identified and the experimental requirements for answering them, we set out to define, without regard to the specific technologies upon which they might be based, the capabilities such light sources would have to deliver in order to dramatically advance the state of research in the areas represented in the programs of the Department of Energy's Office of Basic Energy Sciences (BES). This report is based on the workshop presentations and discussions

  18. Toward Control of Matter: Basic Energy Science Needs for a New Class of X-Ray Light Sources

    Energy Technology Data Exchange (ETDEWEB)

    Arenholz, Elke; Belkacem, Ali; Cocke, Lew; Corlett, John; Falcone, Roger; Fischer, Peter; Fleming, Graham; Gessner, Oliver; Hasan, M. Zahid; Hussain, Zahid; Kevan, Steve; Kirz, Janos; McCurdy, Bill; Nelson, Keith; Neumark, Dan; Nilsson, Anders; Siegmann, Hans; Stocks, Malcolm; Schafer, Ken; Schoenlein, Robert; Spence, John; Weber, Thorsten

    2008-09-24

    Over the past quarter century, light-source user facilities have transformed research in areas ranging from gas-phase chemical dynamics to materials characterization. The ever-improving capabilities of these facilities have revolutionized our ability to study the electronic structure and dynamics of atoms, molecules, and even the most complex new materials, to understand catalytic reactions, to visualize magnetic domains, and to solve protein structures. Yet these outstanding facilities still have limitations well understood by their thousands of users. Accordingly, over the past several years, many proposals and conceptual designs for"next-generation" x-ray light sources have been developed around the world. In order to survey the scientific problems that might be addressed specifically by those new light sources operating below a photon energy of about 3 keV and to identify the scientific requirements that should drive the design of such facilities, a workshop"Science for a New Class of Soft X-Ray Light Sources" was held in Berkeley in October 2007. From an analysisof the most compelling scientific questions that could be identified and the experimental requirements for answering them, we set out to define, without regard to the specific technologies upon which they might be based, the capabilities such light sources would have to deliver in order to dramatically advance the state of research in the areas represented in the programs of the Department of Energy's Office of Basic Energy Sciences (BES). This report is based on the workshop presentations and discussions.

  19. Laboratory-Based Cryogenic Soft X-ray Tomography with Correlative Cryo-Light and Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, David B.; Gelb, Jeff; Palshin, Vadim; Evans, James E.

    2013-02-01

    Here we present a novel laboratory-based cryogenic soft X-ray microscope for whole cell tomography of frozen hydrated samples. We demonstrate the capabilities of this compact cryogenic microscope by visualizing internal sub-cellular structures of Saccharomyces cerevisiae cells. The microscope is shown to achieve better than 50 nm spatial resolution with a Siemens star test sample. For whole biological cells, the microscope can image specimens up to 5 micrometers thick. Structures as small as 90 nm can be detected in tomographic reconstructions at roughly 70 nm spatial resolution following a low cumulative radiation dose of only 7.2 MGy. Furthermore, the design of the specimen chamber utilizes a standard sample support that permits multimodal correlative imaging of the exact same unstained yeast cell via cryo-fluorescence light microscopy, cryo-soft x-ray microscopy and cryo-transmission electron microscopy. This completely laboratory-based cryogenic soft x-ray microscope will therefore enable greater access to three-dimensional ultrastructure determination of biological whole cells without chemical fixation or physical sectioning.

  20. Prospects for an x-ray FEL light source and some possible scientific applications

    International Nuclear Information System (INIS)

    Free electron lasers are now being designed which will operate at wavelengths down to about 1 Aa. Due to the physics of the high-gain, single pass FEL process that these sources will exploit, the radiation produced will have unique properties. In particular: The FEL peak intensity and peak brightness will be many orders of magnitude higher than can be produced by any other source. The pulse length will be less than 1 picosecond, orders of magnitude shorter than can be achieved with any other bright source such as a synchrotron. The FEL radiation will have full transverse coherence and a degeneracy parameter (photons/coherence volume) equal to 109 or more. No other source can produce hard x-radiation with a degeneracy parameter significantly greater than 1. These properties offer the chance to study chemical, biological, and condensed matter dynamical processes with sub-picosecond time resolution and angstrom spatial resolution. The high peak power of the FEL radiation (greater than 1014 W/cm2) could be used to create precisely-controlled chemical and structural modifications inside samples. There is also the possibility that nonlinear x-ray interactions could be used to give increased resolution for spectroscopic studies, to greatly expand the parameter space for atomic physics studies, and to permit new fundamental tests of quantum mechanics. The exploration of these new x-ray techniques will require considerable development, not only in technical areas such as optics and detectors, but also in understanding the basic physics of the interaction of very intense x-radiation with matter. A large collaboration of US institutions is now conducting preliminary research and development in these areas, with the intention of creating an FEL operating at 1.5 Aa in about the year 2006. Germany also has a strong short-wavelength FEL research program, with a soft x-ray FEL under construction and a proposal for a future large facility which would produce a variety of hard and

  1. Quantitative characterization of the x-ray imaging capability of rotating modulation collimators with laser light.

    Science.gov (United States)

    Gaither Iii, C C; Schmahl, E J; Crannell, C J; Dennis, B R; Lang, F L; Orwig, L E; Hartman, C N; Hurford, G J

    1996-12-01

    We developed a method for making quantitative characterizations of bi-grid rotating modulation collimators (RMC's) that are used in a Fourier transform x-ray imager. With appropriate choices of the collimator spacings, this technique can be implemented with a beam-expanded He-Ne laser to simulate the plane wave produced by a point source at infinity even though the RMC's are diffraction limited at the He-Ne wavelength of 632.8 nm. The expanded beam passes through the grid pairs at a small angle with respect to their axis of rotation, and the modulated transmission through the grids as the RMC's rotate is detected with a photomultiplier tube. In addition to providing a quantitative characterization of the RMC's, the method also produces a measured point response function and provides an end-to-end check of the imaging system. We applied our method to the RMC's on the high-energy imaging device (HEIDI) balloon payload in its preflight configuration. We computed the harmonic ratios of the modulation time profile from the laser measurements and compared them with theoretical calculations, including the diffraction effects on irregular grids. Our results indicate the 25-in. (64-cm) x-ray imaging optics on HEIDI are capable of achieving images near the theoretical limit and are not seriously compromised by imperfections in the grids. PMID:21151253

  2. Light ion induced L X-ray production cross-sections in Au and Pb

    International Nuclear Information System (INIS)

    Experimental proton-induced Lα, Lβ, Lγ, Ll and Ltot absolute X-ray production cross-sections for Au and Pb in the incident proton energy range between 1 and 2.5 MeV are presented. The experimental results for X-ray production cross-sections are compared to available data given in Sokhi and Crumpton [R.S. Sokhi, D. Crumpton, At. Data Nucl. Data Tables 30 (1984) 49], Jesus et al. [A.P. Jesus, J.S. Lopes, J.P. Ribeiro, J. Phys. B: At. Mol. Phys. 18 (1985) 2456; A.P. Jesus, T.M. Pinheiro, I.A. Nisa, J.P. Ribeiro, J.S. Lopes, Nucl. Instrum. Methods B15 (1986) 95] and Goudarzi et al. [M. Goudarzi, F. Shokouhi, M. Lamehi-Rachti, P.Olialiy, Nucl. Instrum. Methods Phys. Res. B247 (2006) 218]. The given data are also compared with the predictions of ECPSSR model [W. Brandt, G. Lapicki, Phys. Rev. A23 (1981) 1717

  3. Light ion induced L X-ray production cross-sections in Au and Pb

    Energy Technology Data Exchange (ETDEWEB)

    Ouziane, S. [Faculte de Physique, Universite des Sciences et de Technologie Houari Boumediene, BP 32, El Alia, Bab Ezzouar 16111 Alger (Algeria)], E-mail: sounucl@yahoo.fr; Amokrane, A. [Faculte de Physique, Universite des Sciences et de Technologie Houari Boumediene, BP 32, El Alia, Bab Ezzouar 16111 Alger (Algeria); Ecole Nationale Preparatoire aux Etudes d' Ingeniorat, Rouiba, Alger (Algeria); Toumert, I. [Centre de Recherches Nucleaires d' Alger, 2 Bd Frantz Fanon, BP 399, Alger (Algeria)

    2008-04-15

    Experimental proton-induced L{sub {alpha}}, L{sub {beta}}, L{sub {gamma}}, L{sub l} and L{sub tot} absolute X-ray production cross-sections for Au and Pb in the incident proton energy range between 1 and 2.5 MeV are presented. The experimental results for X-ray production cross-sections are compared to available data given in Sokhi and Crumpton [R.S. Sokhi, D. Crumpton, At. Data Nucl. Data Tables 30 (1984) 49], Jesus et al. [A.P. Jesus, J.S. Lopes, J.P. Ribeiro, J. Phys. B: At. Mol. Phys. 18 (1985) 2456; A.P. Jesus, T.M. Pinheiro, I.A. Nisa, J.P. Ribeiro, J.S. Lopes, Nucl. Instrum. Methods B15 (1986) 95] and Goudarzi et al. [M. Goudarzi, F. Shokouhi, M. Lamehi-Rachti, P.Olialiy, Nucl. Instrum. Methods Phys. Res. B247 (2006) 218]. The given data are also compared with the predictions of ECPSSR model [W. Brandt, G. Lapicki, Phys. Rev. A23 (1981) 1717].

  4. Search for the light dark matter with an X-ray spectrometer

    CERN Document Server

    Boyarsky, A; Neronov, A; Ruchayskiy, O; Boyarsky, Alexey; Herder, Jan Willem den; Neronov, Andrey; Ruchayskiy, Oleg

    2007-01-01

    Sterile neutrinos with the mass in the keV range are interesting warm dark matter (WDM) candidates. The restrictions on their parameters (mass and mixing angle) obtained by current X-ray missions (XMM-Newton or Chandra) can only be improved by less than an order of magnitude in the near future. Therefore the new strategy of search is needed. We compare the sensitivities of existing and planned X-ray missions for the detection of WDM particles with the mass ~1-20 keV. We show that existing technology allows an improvement in sensitivity by a factor of 100. Namely, two different designs can achieve such an improvement: [A] a spectrometer with the high spectral resolving power of 0.1%, wide (steradian) field of view, with small effective area of about cm^2 (which can be achieved without focusing optics) or [B] the same type of spectrometer with a smaller (degree) field of view but with a much larger effective area of 10^3 cm^2 (achieved with the help of focusing optics). To illustrate the use of the "type A" des...

  5. Barrier performance optimization of atomic layer deposited diffusion barriers for organic light emitting diodes using x-ray reflectivity investigations

    International Nuclear Information System (INIS)

    The importance of O3 pulse duration for encapsulation of organic light emitting diodes (OLEDs) with ultra thin inorganic atomic layer deposited Al2O3 layers is demonstrated for deposition temperatures of 50 °C. X-ray reflectivity (XRR) measurements show that O3 pulse durations longer than 15 s produce dense and thin Al2O3 layers. Correspondingly, black spot growth is not observed in OLEDs encapsulated with such layers during 91 days of aging under ambient conditions. This implies that XRR can be used as a tool for process optimization of OLED encapsulation layers leading to devices with long lifetimes

  6. A dedicated superbend x-ray microdiffraction beamline for materials, geo-, and environmental sciences at the advanced light source

    OpenAIRE

    Kunz, Martin; Advanced Light Source

    2009-01-01

    A new facility for microdiffraction strain measurements and microfluorescence mapping has been built on beamline 12.3.2 at the advanced light source of the Lawrence Berkeley National Laboratory. This beamline benefits from the hard x-radiation generated by a 6 T superconducting bending magnet (superbend) This provides a hard x-ray spectrum from 5 to 22 keV and a flux within a 1 mu m spot of ~;;5x109 photons/ s (0.1percent bandwidth at 8 keV). The radiation is relayed from the superbend source...

  7. THE LACK OF DIFFUSE, NON-THERMAL HARD X-RAY EMISSION IN THE COMA CLUSTER: THE SWIFT BURST ALERT TELESCOPE'S EYE VIEW

    International Nuclear Information System (INIS)

    The Coma Cluster of galaxies hosts the brightest radio halo known and has therefore been the target of numerous searches for associated inverse Compton (IC) emission, particularly at hard X-ray energies where the IC signal must eventually dominate over thermal emission. The most recent search with the Suzaku Hard X-ray Detector failed to confirm previous IC detections with RXTE and BeppoSAX, instead setting an upper limit 2.5 times below their non-thermal flux. However, this discrepancy can be resolved if the IC emission is very extended, beyond the scale of the cluster radio halo. Using reconstructed sky images from the 58-month Swift Burst Alert Telescope (BAT) all-sky survey, the feasibility of such a solution is investigated. Building on Renaud et al., we test and implement a method for extracting the fluxes of extended sources, assuming specified spatial distributions. BAT spectra are jointly fit with an XMM-Newton EPIC-pn spectrum derived from mosaic observations. We find no evidence for large-scale IC emission at the level expected from the previously detected non-thermal fluxes. For all non-thermal spatial distributions considered, which span the gamut of physically reasonable IC models, we determine upper limits for which the largest (most conservative) limit is ∼-12 erg s-1 cm-2 (20-80 keV), which corresponds to a lower limit on the magnetic field B > 0.2 μ G. A nominal flux upper limit of -12 erg s-1 cm-2, with corresponding B > 0.25 μ G, is derived for the most probable IC distribution given the size of the radio halo and likely magnetic field radial profile.

  8. Soft X-ray extended emissions of short gamma-ray bursts as electromagnetic counterparts of compact binary mergers: possible origin and detectability

    International Nuclear Information System (INIS)

    We investigate the possible origin of extended emissions (EEs) of short gamma-ray bursts with an isotropic energy of ∼1050-51 erg and a duration of a few 10 s to ∼100 s, based on a compact binary (neutron star (NS)-NS or NS-black hole (BH)) merger scenario. We analyze the evolution of magnetized neutrino-dominated accretion disks of mass ∼0.1 M ☉ around BHs formed after the mergers and estimate the power of relativistic outflows via the Blandford-Znajek (BZ) process. We show that a rotation energy of the BH up to ≳ 1052 erg can be extracted with an observed timescale of ≳ 30(1 + z) s with a relatively small disk viscosity parameter of α < 0.01. Such a BZ power dissipates by clashing with non-relativistic pre-ejected matter of mass M ∼ 10–(2-4) M ☉, and forms a mildly relativistic fireball. We show that the dissipative photospheric emissions from such fireballs are likely in the soft X-ray band (1-10 keV) for M ∼ 10–2 M ☉, possibly in NS-NS mergers, and in the BAT band (15-150 keV) for M ∼ 10–4 M ☉, possibly in NS-BH mergers. In the former case, such soft EEs can provide a good chance of ∼6 yr−1 (ΔΩsoftEE/4π) (RGW/40 yr−1) for simultaneous detections of the gravitational waves with a ∼0.°1 angular resolution by soft X-ray survey facilities like the Wide-Field MAXI. Here, ΔΩsoftEE is the beaming factor of the soft EEs and RGW is the NS-NS merger rate detectable by the advanced LIGO, the advanced Virgo, and KAGRA.

  9. VUV and X-ray coherent light with tunable polarization from single-pass free-electron lasers

    CERN Document Server

    Spezzani, C; Diviacco, B; Ferrari, E; Geloni, G; Karantzoulis, E; Mahieu, B; Vento, M; De Ninno, G

    2011-01-01

    Tunable polarization over a wide spectral range is a required feature of light sources employed to investigate the properties of local symmetry in both condensed and low-density matter. Among new-generation sources, free-electron lasers possess a unique combination of very attractive features, as they allow to generate powerful and coherent ultra-short optical pulses in the VUV and X-ray spectral range. However, the question remains open about the possibility to freely vary the light polarization of a free-electron laser, when the latter is operated in the so-called nonlinear harmonic-generation regime. In such configuration, one collects the harmonics of the free-electron laser fundamental emission, gaining access to the shortest possible wavelengths the device can generate. In this letter we provide the first experimental characterization of the polarization of the harmonic light produced by a free-electron laser and we demonstrate a method to obtain tunable polarization in the VUV and X-ray spectral range....

  10. Constraints on Compact Star Parameters from Burst Oscillation Light Curves of the Accreting Millisecond Pulsar XTE J1814-338

    CERN Document Server

    Bhattacharya, S; Miller, M C; Markwardt, C B; Bhattacharyya, Sudip; Strohmayer, Tod E.; Markwardt, Craig B.

    2004-01-01

    Detailed modeling of the millisecond brightness oscillations from low mass X-ray binaries during thermonuclear bursts can provide us with important information about compact star parameters. Until now the implementation of this idea has not been entirely successful, largely because of the negligible amount of harmonic content in burst oscillation lightcurves. However, the recent discovery of unique, non-sinusoidal burst oscillation lightcurves from the accreting millisecond pulsar XTE J1814-338 has changed this situation. We, therefore, for the first time, make use of this opportunity to constrain compact star structure parameters effectively. In our detailed study of the lightcurves of 22 bursts we fit the burst oscillation lightcurves with fully general relativistic models that include light-bending and frame-dragging for lightcurve calculation, and compute numerically the structure of compact stars using realistic equations of state. We find that the 90% confidence interval of the dimensionless radius to m...

  11. Impulsive solar X-ray bursts. 4: Polarization, directivity and spectrum of the reflected and total bremsstrahlung radiation from a beam of electrons directed toward the photosphere

    Science.gov (United States)

    Langer, S. H.; Petrosian, V.

    1976-01-01

    A Monte Carlo method is described for evaluation of the spectrum, directivity and polarization of X-rays diffusely reflected from stellar photospheres. the accuracy of the technique is evaluated through comparison with analytic results. Using the characteristics of the incident X-rays of the model for solar X-ray flares, the spectrum, directivity and polarization of the reflected and the total X-ray fluxes are evaluated. The results are compared with observations.

  12. Infrared (IR) vs x-ray power generation in the SLAC Linac Coherent Light Source (LCLS)

    International Nuclear Information System (INIS)

    The LCLS, a Free-Electron Laser (FEL) designed for operation at a first harmonic energy of 300 eV (λ congruent 40 Angstrom) in the Self-Amplified Spontaneous Emission (SASE) regime, will utilize electron bunches compressed down to durations of <0.5ps, or lengths of <150 μ. It is natural to inquire whether coherent radiation of this (and longer) wavelength will constitute a significant component of the total coherent output of the FEL. In this paper a determination of a simple upper bound on the IR that can be generated by the compressed bunches is outlines. Under the assumed operating parameters of the LCLS undulator, it is shown that that IR component of the coherent output should be strongly dominated by the x-ray component

  13. Precision spectroscopy of light kaonic atom X-rays in the SIDDHARTA experiment

    Science.gov (United States)

    Cargnelli, M.; Bazzi, M.; Beer, G.; Bombelli, L.; Bragadireanu, A. M.; Curceanu, C.; Fiorini, C.; Frizzi, T.; Ghio, F.; Girolami, B.; Guaraldo, C.; Hayano, R.; Iliescu, M.; Ishiwatari, T.; Iwasaki, M.; Kienle, P.; Lechner, P.; Sandri, P. Levi; Longoni, A.; Lucherini, V.; Marton, J.; Okada, S.; Pietreanu, D.; Ponta, T.; Vidal, A. Romero; Scordo, A.; Shi, H.-X.; Sirghi, D. L.; Sirghi, F.; Soltau, H.; Strüder, L.; Tatsuno, H.; Doce, O. Vazquez; Widmann, E.; Zmeskal, J.

    2011-10-01

    The KN system at rest makes a sensitive testing ground for low energy QCD. At the DAΦNE electron-positron collider of Laboratori Nazionali di Frascati we study kaonic atoms, taking advantage of the low-energy kaons from Φ-mesons decaying nearly at rest. The DEAR (DAΦNE Exotic Atom Research) experiment at LNF delivered the most precise data on kaonic hydrogen up to now. DEAR and its follow-up experiment SIDDHARTA (Silicon Drift Detector for Hadronic Atom Research by Timing Application) are using X-ray spectroscopy of kaonic atoms to measure the strong interaction induced shift and width of the ground state. SIDDHARTA is the first experiment on kaonic helium-3 and deuterium ever, and kaonic hydrogen was remeasured with improved precision.

  14. Precision spectroscopy of light kaonic atom X-rays in the SIDDHARTA experiment

    International Nuclear Information System (INIS)

    The KN system at rest makes a sensitive testing ground for low energy QCD. At the DAΦNE electron-positron collider of Laboratori Nazionali di Frascati we study kaonic atoms, taking advantage of the low-energy kaons from Φ-mesons decaying nearly at rest. The DEAR (DAΦNE Exotic Atom Research) experiment at LNF delivered the most precise data on kaonic hydrogen up to now. DEAR and its follow-up experiment SIDDHARTA (Silicon Drift Detector for Hadronic Atom Research by Timing Application) are using X-ray spectroscopy of kaonic atoms to measure the strong interaction induced shift and width of the ground state. SIDDHARTA is the first experiment on kaonic helium-3 and deuterium ever, and kaonic hydrogen was remeasured with improved precision.

  15. Ultrafast dynamics driven by intense light pulses from atoms to solids, from lasers to intense X-rays

    CERN Document Server

    Gräfe, Stefanie

    2016-01-01

    This book documents the recent vivid developments in the research field of ultrashort intense light pulses for probing and controlling ultrafast dynamics. The recent fascinating results in studying and controlling ultrafast dynamics in ever more complicated systems such as (bio-)molecules and structures of meso- to macroscopic sizes on ever shorter time-scales are presented. The book is written by some of the most eminent experimental and theoretical experts in the field. It covers the new groundbreaking research directions that were opened by the availability of new light sources such as fully controlled intense laser fields with durations down to a single oscillation cycle, short-wavelength laser-driven attosecond pulses and intense X-ray pulses from the upcoming free electron lasers. These light sources allowed the investigation of dynamics in atoms, molecules, clusters, on surfaces and very recently also in nanostructures and solids in new regimes of parameters which, in turn, led to the identification of...

  16. Correlative cryogenic tomography of cells using light and soft x-rays

    International Nuclear Information System (INIS)

    Correlated imaging is the process of imaging a specimen with two complementary modalities, and then combining the two data sets to create a highly informative, composite view. A recent implementation of this concept has been the combination of soft x-ray tomography (SXT) with fluorescence cryogenic microscopy (FCM). SXT–FCM is used to visualize cells that are held in a near-native, cryopreserved. The resultant images are, therefore, highly representative of both the cellular architecture and molecular organization in vivo. SXT quantitatively visualizes the cell and sub-cellular structures; FCM images the spatial distribution of fluorescently labeled molecules. Here, we review the characteristics of SXT–FCM, and briefly discuss how this method compares with existing correlative imaging techniques. We also describe how the incorporation of a cryo-rotation stage into a cryogenic fluorescence microscope allows acquisition of fluorescence cryogenic tomography (FCT) data. FCT is optimally suited for correlation with SXT, since both techniques image the specimen in 3-D, potentially with similar, isotropic spatial resolution. - Highlights: • We describe a new correlated imaging modality: soft x-ray tomography combined (SXT) with confocal fluorescence tomography (CFT). • Data from the two modalities are combined accurately and precisely using fiducials visible in both types of data. • Cells imaged by SXT–CFT are maintained close to their native state by cryo-preservation. • SXT–CFT is applicable to most cell types, especially cells grown in suspension. • ‘Super-resolution’ microscopes being developed for CFT data acquisition match the spatial resolution of SXT

  17. The Advanced Light Source at Lawrence Berkeley Laboratory: A high-brightness soft x-ray synchrotron-radiation facility

    International Nuclear Information System (INIS)

    The Advanced Light Source, a third-generation national synchrotron-radiation facility now under construction at the Lawrence Berkeley Laboratory, is scheduled to begin serving qualified users across a broad spectrum of research areas in the spring of 1993. Based on a low-emittance electron storage ring optimized to operate at 1.5 GeV, the ALS will have 10 long straight sections available for insertion devices (undulators and wigglers) and 24 high-quality bend-magnet ports. The short pulse width (30--50 ns) will be ideal for time-resolved measurements. Undulators will generate high-brightness soft x-ray and ultraviolet (XUV) radiation from below 20 eV to above 2 keV. Wigglers and bend magnets will extend the spectrum by generating high fluxes of hard x-rays to photon energies above 10 keV. The ALS will support an extensive research program in which XUV radiation is used to study matter in all its varied gaseous, liquid, and solid forms. The high brightness will open new areas of research in the materials sciences, such as spatially resolved spectroscopy (spectromicroscopy). Biological applications will include x-ray microscopy with element-specific sensitivity in the water window of the spectrum where water is much more transparent than protein. The ALS will be an excellent research tool for atomic physics and chemistry because the high flux will allow measurements to be made with tenuous gas-phase targets. 8 refs., 7 figs., 3 tabs

  18. Nanoplasma Dynamics of Single Large Xenon Clusters Irradiated with Superintense X-Ray Pulses from the Linac Coherent Light Source Free-Electron Laser

    OpenAIRE

    Gorkhover, T.; Adolph, M; Rupp, D.; Schorb, S.; Epp, S.; Erk, B.; Foucar, L.; R. Hartmann; Kimmel, N; Kühnel, K.; Rolles, D.; Rudek, B.; Rudenko, A.; Andritschke, R.; Aquila, A.

    2012-01-01

    The plasma dynamics of single mesoscopic Xe particles irradiated with intense femtosecond x-ray pulses exceeding 10¹⁶  W/cm² from the Linac Coherent Light Source free-electron laser are investigated. Simultaneous recording of diffraction patterns and ion spectra allows eliminating the influence of the laser focal volume intensity and particle size distribution. The data show that for clusters illuminated with intense x-ray pulses, highly charged ionization fragments in a narrow distribution a...

  19. Soft X-ray Extended Emissions of Short Gamma-Ray Bursts as Electromagnetic Counterparts of Compact Binary Mergers; Possible Origin and Detectability

    CERN Document Server

    Nakamura, Takashi; Nakauchi, Daisuke; Suwa, Yudai; Sakamoto, Takanori; Kawai, Nobuyuki

    2013-01-01

    We investigate the possible origin of extended emissions (EE) of short gamma-ray bursts (SGRBs) with an isotropic energy of $\\sim 10^{50\\mbox{-}51} \\ \\rm erg$ and a duration of $\\sim 100 \\ \\rm s$, based on the compact binary (neutron star (NS)-NS or NS-black hole (BH)) merger scenario. We analyze the evolution of magnetized neutrino-dominated accretion disks of mass $\\sim 0.1 \\ M_\\odot$ around BHs formed after the mergers, and estimate the power of relativistic outflows via the Blandford-Znajek (BZ) process. We show that a rotation energy of the BH up to $\\sim 10^{53} \\ \\rm erg$ can be extracted with a time scale of $\\sim 100 \\ \\rm s$ with a disk viscosity parameter of $\\alpha \\sim 0.01$. Such a BZ power dissipates by clashing with non-relativistic pre-ejected matter of mass $M \\sim 10^{-(2\\mbox{-}4)} \\ M_\\odot$, and form a mildly relativistic fireball. We show that the dissipative photospheric emissions from such fireballs are likely in soft X-ray band ($1\\mbox{-}10 \\ \\rm keV$) for $M \\sim 10^{-2} M_\\odot$ p...

  20. National synchrotron light source user's manual: Guide to the VUV and x-ray beamlines: Third edition

    International Nuclear Information System (INIS)

    This report contains information on the following topics: A Word on the Writing of Beamline Descriptions; Beamline Equipment Utilization for General Users; the Vacuum Ultraviolet (VUV) Storage Ring and Beamlines; VUV Beamline Descriptions--An Explanation; VUV Beamline Descriptions; X-Ray Storage Ring and Beamlines; X-Ray Beamline Descriptions--An Explanation; and X-Ray Beamline Descriptions

  1. Light output measurements and computational models of microcolumnar CsI scintillators for x-ray imaging

    International Nuclear Information System (INIS)

    Purpose: The authors report on measurements of light output and spatial resolution of microcolumnar CsI:Tl scintillator detectors for x-ray imaging. In addition, the authors discuss the results of simulations aimed at analyzing the results of synchrotron and sealed-source exposures with respect to the contributions of light transport to the total light output. Methods: The authors measured light output from a 490-μm CsI:Tl scintillator screen using two setups. First, the authors used a photomultiplier tube (PMT) to measure the response of the scintillator to sealed-source exposures. Second, the authors performed imaging experiments with a 27-keV monoenergetic synchrotron beam and a slit to calculate the total signal generated in terms of optical photons per keV. The results of both methods are compared to simulations obtained with hybridMANTIS, a coupled x-ray, electron, and optical photon Monte Carlo transport package. The authors report line response (LR) and light output for a range of linear absorption coefficients and describe a model that fits at the same time the light output and the blur measurements. Comparing the experimental results with the simulations, the authors obtained an estimate of the absorption coefficient for the model that provides good agreement with the experimentally measured LR. Finally, the authors report light output simulation results and their dependence on scintillator thickness and reflectivity of the backing surface. Results: The slit images from the synchrotron were analyzed to obtain a total light output of 48 keV−1 while measurements using the fast PMT instrument setup and sealed-sources reported a light output of 28 keV−1. The authors attribute the difference in light output estimates between the two methods to the difference in time constants between the camera and PMT measurements. Simulation structures were designed to match the light output measured with the camera while providing good agreement with the measured LR

  2. Pulse Phase Dependence of the Magnetar Bursts

    Indian Academy of Sciences (India)

    Chetana Jain; Anjan Dutta; Biswajit Paul

    2007-12-01

    We report here results from a study of X-ray bursts from 3 magnetar candidates (SGR 1806–20, SGR 1900+14 and AXP 1E 2259+586). We have searched for a pulse phase dependence of the X-ray burst rate from these sources. X-ray light curves were obtained with the Proportional Counter Array on-board the Rossi X-ray Timing Explorer during the periods of intense burst activity in these sources. On detailed analysis of the three sources, we found a very significant burst rate for all pulsar phases. However, some locations appear to produce bursts slightly more often, rendering the non-isotropic distribution. Only in the case of SGR 1900+14, there is a clear pulse phase dependence of burst rate.

  3. Soft X-ray extended emissions of short gamma-ray bursts as electromagnetic counterparts of compact binary mergers: possible origin and detectability

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Takashi; Nakauchi, Daisuke [Department of Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Kashiyama, Kazumi [Department of Astronomy and Astrophysics, Department of Physics, Center for Particle and Gravitational Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Suwa, Yudai [Yukawa Institute for Theoretical Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Sakamoto, Takanori [Department of Physics and Mathematics, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-5258 (Japan); Kawai, Nobuyuki [Department of Physics, Tokyo Insititute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

    2014-11-20

    We investigate the possible origin of extended emissions (EEs) of short gamma-ray bursts with an isotropic energy of ∼10{sup 50-51} erg and a duration of a few 10 s to ∼100 s, based on a compact binary (neutron star (NS)-NS or NS-black hole (BH)) merger scenario. We analyze the evolution of magnetized neutrino-dominated accretion disks of mass ∼0.1 M {sub ☉} around BHs formed after the mergers and estimate the power of relativistic outflows via the Blandford-Znajek (BZ) process. We show that a rotation energy of the BH up to ≳ 10{sup 52} erg can be extracted with an observed timescale of ≳ 30(1 + z) s with a relatively small disk viscosity parameter of α < 0.01. Such a BZ power dissipates by clashing with non-relativistic pre-ejected matter of mass M ∼ 10{sup –(2-4)} M {sub ☉}, and forms a mildly relativistic fireball. We show that the dissipative photospheric emissions from such fireballs are likely in the soft X-ray band (1-10 keV) for M ∼ 10{sup –2} M {sub ☉}, possibly in NS-NS mergers, and in the BAT band (15-150 keV) for M ∼ 10{sup –4} M {sub ☉}, possibly in NS-BH mergers. In the former case, such soft EEs can provide a good chance of ∼6 yr{sup −1} (ΔΩ{sub softEE}/4π) (R{sub GW}/40 yr{sup −1}) for simultaneous detections of the gravitational waves with a ∼0.°1 angular resolution by soft X-ray survey facilities like the Wide-Field MAXI. Here, ΔΩ{sub softEE} is the beaming factor of the soft EEs and R{sub GW} is the NS-NS merger rate detectable by the advanced LIGO, the advanced Virgo, and KAGRA.

  4. X-ray plateaus followed by sharp drops in GRBs 060413, 060522,060607A and 080330: Further evidences for central engine afterglow from gamma-ray bursts

    Institute of Scientific and Technical Information of China (English)

    Xiao-Hui Zhang

    2009-01-01

    The X-ray afterglows of GRBs 060413, 060522, 060607A and 080330 are characterized by a plateau followed by a very sharp drop. The plateau could be explained within the framework of the external forward shock model but the sharp drop can not.We interpret the plateau as the afterglows of magnetized central engines, plausibly magnetars. In this model, the X-ray afterglows are powered by the internal magnetic energy dissipation and the sudden drop is caused by the collapse of the magnetar. Accordingly,the X-ray plateau photons should have a high linear polarization, which can be tested by future X-ray polarimetry.

  5. High-field strong-focusing undulator designs for X-ray Linac Coherent Light Source (LCLS) applications

    International Nuclear Information System (INIS)

    Linac-driven X-Ray Free Electron Lasers (e.g., Linac Coherent Light Sources (LCLSs)), operating on the principle of single-pass saturation in the Self-Amplified Spontaneous Emission (SASE) regime typically require multi-GeV beam energies and undulator lengths in excess of tens of meters to attain sufficient gain in the 1 angstrom--0.1 angstrom range. In this parameter regime, the undulator structure must provide: (1) field amplitudes B0 in excess of 1T within periods of 4cm or less, (2) peak on-axis focusing gradients on the order of 30T/m, and (3) field quality in the 0.1%--0.3% range. In this paper the authors report on designs under consideration for a 4.5--1.5 angstrom LCLS based on superconducting (SC), hybrid/PM, and pulsed-Cu technologies

  6. Heavy concerns about the light axino explanation of the 3.5 keV X-ray line

    Directory of Open Access Journals (Sweden)

    Stefano Colucci

    2015-11-01

    Full Text Available An unidentified 3.5 keV line from X-ray observations of galaxy clusters has been reported recently. Although still under scrutiny, decaying dark matter could be responsible for this signal. We investigate whether an axino with a mass of 7 keV could explain the line, keeping the discussion as model independent as possible. We point out several obstacles, which were overlooked in the literature, and which make the axino an unlikely candidate. The only viable scenario predicts a light metastable neutralino, with a mass between 0.1 and 10 GeV and a lifetime between 10−3 and 104 s.

  7. Development of a microsecond X-ray protein footprinting facility at the Advanced Light Source

    OpenAIRE

    Gupta, Sayan; Celestre, Richard; Petzold, Christopher J.; Chance, Mark R.; Ralston, Corie

    2014-01-01

    Radiolytic labeling is established as a collaborative program at the Advanced Light Source (ALS). Results indicate that white-light bend-magnet beamlines at the ALS produce flux densities high enough to allow microsecond exposures yielding sufficient modification to conduct footprinting experiments, representing a significant advance for the footprinting experiment.

  8. Evaluation techniques for x-ray mirrors and systems using visible light

    International Nuclear Information System (INIS)

    Severely diffraction-broadened visible light images from grazing incidence optical systems are measured and analyzed using a diffraction integral model to predict slope errors and image quality at XUV wavelengths

  9. Suppressing effect of antimutagenic flavorings on chromosome aberrations induced by UV-light or X-rays in cultured Chinese hamster cells

    International Nuclear Information System (INIS)

    Chromosome aberrations induces by UV-light or X-rays were suppressed by the post-treatment with antimutagenic flavorings, such as anisaldehyde, cinnamaldehyde, coumarin, and vanillin. UV- or X-ray-irradiated surviving cells increased in the presence of each flavouring. X-ray-induced breakage-type and exchange-type chromosome aberrations were suppressed by the vanillin treatment in the G1 phase of the cell cycle and a greater decrease in the number of X-ray-induced chromosome aberrations during G1 holding was observed in the presence of vanillin. Furthermore, a greater decrease in the number of X-ray-induced DNA single-strand breaks was observed in the presence of vanillin. Treatment with vanillin in the G2 phase suppressed UV-and X-ray-induced breakage-type but not exchange-type chromosome aberrations. The suppression of breakage-type aberrations was assumed to be due to a modification of the capability of the post-replicational repair of DNA double-strand breaks. (author). 28 refs.; 5 figs.; 6 tabs

  10. Revealing a hard X-ray spectral component reverberating within one light hour of the central Supermassive Black Hole in Ark 564

    CERN Document Server

    Giustini, M; Reeves, J N; Miller, L; Legg, E; Kraemer, S B; George, I M

    2015-01-01

    Ark 564 (z=0.0247) is an X-ray bright NLS1. By using advanced X-ray timing techniques, Legg et al. (2012) discovered an excess of "delayed" emission in the hard X-ray band (4-7.5 keV) following about 1000 seconds after "flaring" light in the soft X-ray band (0.4-1 keV). We report on the X-ray spectral analysis of eight XMM-Newton and one Suzaku observation of Ark 564. High-resolution spectroscopy was performed with the RGS in the soft X-ray band, while broad-band spectroscopy was performed with the EPIC-pn and XIS/PIN instruments. We analysed time-averaged, flux-selected, and time-resolved spectra. Despite the large variability in flux, the broad band spectral shape of Ark 564 is not dramatically varying and can be reproduced either by a superposition of a power law and a blackbody emission, or by a Comptonized power law emission model. High resolution spectroscopy revealed the presence of ionised gas along the line of sight at the systemic redshift of the source, with a low column density and a range of ioni...

  11. Science Goals and First Light Analysis from the Miniature X-ray Solar Spectrometer (MinXSS) CubeSat

    Science.gov (United States)

    Caspi, Amir; Woods, Thomas N.; Warren, Harry; Chamberlin, Phillip C.; Jones, Andrew; Mason, James; McTiernan, James; Moore, Christopher; Palo, Scott; Solomon, Stanley

    2016-05-01

    The Miniature X-ray Solar Spectrometer (MinXSS) is a 3U CubeSat with deployment from the ISS planned in Q2 2016. Its goal is to measure the solar soft X-ray (SXR) spectral irradiance, an observational signature of hot plasma in the solar corona. Over the last few decades, there have been very few spectrally resolved observations from ~0.2 to ~4 keV (~0.3-6 nm). This range is sensitive to high-temperature plasma and contains many spectral lines (e.g., Mg, Si, Fe, S, Ar), the abundances of which probe plasma transport and provide valuable constraints on plasma heating mechanisms during both flares and quiescence. This solar SXR emission is primarily absorbed in the E-region of Earth's ionosphere, and the subsequently driven dynamical processes are still poorly understood, in large part because the energy distribution of the incident SXRs is not yet well characterized.MinXSS flies a miniature commercial off-the-shelf soft X-ray (SXR) spectrometer, the Amptek X123-SDD. The silicon drift detector has 0.5 mm fully depleted thickness and a 25 mm^2 physical area, with a ~16 micron Be entrance window; with on-board thermoelectric cooling and pulse pile-up rejection, it is sensitive to solar SXRs from ~0.5 to 30 keV with ~0.15 keV FWHM resolution. MinXSS also includes a broadband SXR photometer, providing an integrated intensity over a similar energy range for comparison, cross-calibration, and additional data, especially useful during more intense flares at the upper end of the X123 dynamic range.We present the MinXSS science goals for studying hot plasma in the solar corona, including impulsive flare heating and quiescent coronal heating, and the impact of the resultant SXR emission on Earth's ionosphere, thermosphere, and mesosphere. We present analysis of MinXSS first light results (depending on deployment date from the ISS), as well as modeling and predictions of future observations over the MinXSS 6-12 month mission lifetime.

  12. A dedicated superbend x-ray microdiffraction beamline for materials, geo-, and environmental sciences at the advanced light source

    Energy Technology Data Exchange (ETDEWEB)

    Advanced Light Source; Kunz, Martin; Tamura, Nobumichi; Chen, Kai; MacDowell, Alastair A.; Celestre, Richard S.; Church, Matthew M.; Fakra, Sirine; Domning, Edward E.; Glossinger, James M.; Kirschman, Jonathan L.; Morrison, Gregory Y.; Plate, Dave W.; Smith, Brian V.; Warwick, Tony; Padmore, Howard A.; Ustundag, Ersan; Yashchuk, Valeriy V.

    2009-03-24

    A new facility for microdiffraction strain measurements and microfluorescence mapping has been built on beamline 12.3.2 at the advanced light source of the Lawrence Berkeley National Laboratory. This beamline benefits from the hard x-radiation generated by a 6 T superconducting bending magnet (superbend) This provides a hard x-ray spectrum from 5 to 22 keV and a flux within a 1 mu m spot of ~;;5x109 photons/ s (0.1percent bandwidth at 8 keV). The radiation is relayed from the superbend source to a focus in the experimental hutch by a toroidal mirror. The focus spot is tailored bytwo pairs of adjustable slits, which serve as secondary source point. Inside the lead hutch, a pair of Kirkpatrick-Baez (KB) mirrors placed in a vacuum tank refocuses the secondary slit source onto the sample position. A new KB-bending mechanism with active temperature stabilization allows for more reproducible and stable mirror bending and thus mirror focusing. Focus spots around 1 um are routinely achieved and allow a variety of experiments, which have in common the need of spatial resolution. The effective spatial resolution (~;;0.2 mu m) is limited by a convolution of beam size, scan-stage resolution, and stage stability. A four-bounce monochromator consisting of two channel-cut Si(111) crystals placed between the secondary source and KB-mirrors allows for easy changes between white-beam and monochromatic experiments while maintaining a fixed beam position. High resolution stage scans are performed while recording a fluorescence emission signal or an x-ray diffraction signal coming from either a monochromatic or a white focused beam. The former allows for elemental mapping, whereas the latter is used to produce two-dimensional maps of crystal-phases, -orientation, -texture, and -strain/stress. Typically achieved strain resolution is in the order of 5x10-5 strain units. Accurate sample positioning in the x-ray focus spot is achieved with a commercial laser-triangulation unit. A Si

  13. Radiation-damage-free quantum crystallography and resolution-enhanced x-ray imaging techniques using quantum multipath interference of thermal light

    CERN Document Server

    Li, Zheng; Medvedev, Nikita; Wang, Fenglin; Chapman, Henry N; Shih, Yanhua

    2016-01-01

    Using higher order coherence of thermal light sources, we can achieve enhancement of resolution of standard x-ray imaging techniques, such as x-ray diffraction and phase contrast imaging. The cost of implementing such schemes is minimal comparing to the schemes using entangled two-photon pairs. The proposed diffractive quan- tum crystallography using multipath interference of thermal light can be eventually free of radiation damage, because the diffraction pattern could be formed by using low energy photons of optical wavelength. Thus it is promising to apply the proposed quantum crystallography scheme to nanocrystalline or non-crystalline samples that are too difficult to be crystallized.

  14. X-ray fluorescence microscopy of light elements in cells: self-absorption correction by integration of compositional and morphological measurements

    International Nuclear Information System (INIS)

    We present here a new methodology for quantitative mapping of light elements in cells, based on combination of compositional and morphological information, derived respectively by X-ray Fluorescence Microscopy (XRFM), Atomic Force Microscopy and Scanning Transmission X-ray Microscopy (STXM). Since XRFM of light elements (carbon, nitrogen, oxygen, sodium and magnesium), are strongly influenced by self-absorption, we developed an algorithm to correct for this effect, using the morphological and structural information provided by AFM and STXM. Finally, the corrected distributions have been obtained, thus allowing quantitative mapping

  15. Light output measurements and computational models of microcolumnar CsI scintillators for x-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Nillius, Peter, E-mail: nillius@mi.physics.kth.se; Klamra, Wlodek; Danielsson, Mats [Royal Institute of Technology (KTH), Stockholm SE-100 44 (Sweden); Sibczynski, Pawel [National Centre for Nuclear Research, Otwock 05-400 (Poland); Sharma, Diksha; Badano, Aldo [Division of Imaging, Diagnostics, and Software Reliability, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, FDA, Silver Spring, Maryland 20993 (United States)

    2015-02-15

    Purpose: The authors report on measurements of light output and spatial resolution of microcolumnar CsI:Tl scintillator detectors for x-ray imaging. In addition, the authors discuss the results of simulations aimed at analyzing the results of synchrotron and sealed-source exposures with respect to the contributions of light transport to the total light output. Methods: The authors measured light output from a 490-μm CsI:Tl scintillator screen using two setups. First, the authors used a photomultiplier tube (PMT) to measure the response of the scintillator to sealed-source exposures. Second, the authors performed imaging experiments with a 27-keV monoenergetic synchrotron beam and a slit to calculate the total signal generated in terms of optical photons per keV. The results of both methods are compared to simulations obtained with hybridMANTIS, a coupled x-ray, electron, and optical photon Monte Carlo transport package. The authors report line response (LR) and light output for a range of linear absorption coefficients and describe a model that fits at the same time the light output and the blur measurements. Comparing the experimental results with the simulations, the authors obtained an estimate of the absorption coefficient for the model that provides good agreement with the experimentally measured LR. Finally, the authors report light output simulation results and their dependence on scintillator thickness and reflectivity of the backing surface. Results: The slit images from the synchrotron were analyzed to obtain a total light output of 48 keV{sup −1} while measurements using the fast PMT instrument setup and sealed-sources reported a light output of 28 keV{sup −1}. The authors attribute the difference in light output estimates between the two methods to the difference in time constants between the camera and PMT measurements. Simulation structures were designed to match the light output measured with the camera while providing good agreement with the

  16. Comparison of the time behavior in the separation of light and heavy materials in X-ray backscattered method as a diagnostic tool in inspection

    Science.gov (United States)

    Faezeh, Rahmani; Sepideh Sadat, Azimi; Esmaiel, Bayat; Vahid, Dost Mohammadi

    2016-03-01

    X-ray backscattered method based on Compton backscattering is used in the inspection field. In contrast to transmission method, source and detectors are positioned on one side of the target, so in the situation that transmission inspection is difficult, X-ray backscattered method can be provided suitable data in the inspection field. Also, detection of hidden explosives and narcotic materials are very difficult or impossible in transmission methods. High intensity backscattered beam from light materials (low-Z), such as explosives and narcotics, in comparison to the heavy materials (high-Z), made this method as the strong technique in inspection. X-ray and gamma photons scattered by the light material (such as PE and PTFE) as well as heavy material (such as Fe and Cu) were studied using MCNPX2.6 Monte Carlo code. The results showed that rise time of pulse from light materials are slower than that of from heavy materials due to multi scattering of low energy photons in the light ones, so time expansion would occur in signals from light elements. If measurement is possible, the difference in time behavior can be used as a novel method in complementary diagnostic tool beside the use of pulse height in X-ray backscattered method.

  17. X-ray Optics and Diagnostics for the First Experiments on the Linac Coherent Light Source

    International Nuclear Information System (INIS)

    The Linac Coherent Light Source (LCLS) is a 1.5 to 15 (angstrom)-Wavelength free-electron laser (FEL), currently proposed for the Stanford Linear Accelerator Center (SLAC). The photon output consists of high brightness, transversely coherent pulses with duration < 300 fs, together with a broad spontaneous spectrum with total power comparable to the coherent output. The output fluence, and pulse duration, pose special challenges for optical component and diagnostic designs. We discuss some of the proposed solutions, and give specific examples related to the planned initial experiments

  18. X-ray Optics and Diagnostics for the First Experiments on the Linac Coherent Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Wootton, A; Arthur, J; Barbee, T; Bionta, R; London, R; Park, H-S; Ryutov, D; Spiller, E; Tatchyn, R

    2001-06-13

    The Linac Coherent Light Source (LCLS) is a 1.5 to 15 {angstrom}-wavelength free-electron laser (FEL), currently proposed for the Stanford Linear Accelerator Center (SLAC). The photon output consists of high brightness, transversely coherent pulses with duration < 300 fs, together with a broad spontaneous spectrum with total power comparable to the coherent output. The output fluence, and pulse duration, pose special challenges for optical component and diagnostic designs. We discuss some of the proposed solutions, and give specific examples related to the planned initial experiments.

  19. Impulsive solar X-ray bursts. III - Polarization, directivity, and spectrum of the reflected and total bremsstrahlung radiation from a beam of electrons directed toward the photosphere

    Science.gov (United States)

    Langer, S. H.; Petrosian, V.

    1977-01-01

    The paper presents the spectrum, directivity, and state of polarization of the bremsstrahlung radiation expected from a beam of high-energy electrons spiraling along radial magnetic field lines toward the photosphere. A Monte Carlo method is then described for evaluation of the spectrum, directivity, and polarization of X-rays diffusely reflected from stellar photospheres. The accuracy of the technique is evaluated through comparison with analytic results. The calculated characteristics of the incident X-rays are used to evaluate the spectrum, directivity, and polarization of the reflected and total X-ray fluxes. The results are compared with observations.

  20. Mircobeam X-ray total scattering experiments at the high-pressure beamline X17B3 at the National Synchrotron Light Source

    Science.gov (United States)

    Hong, X.; Ehm, L.; Duffy, T. S.; Weidner, D. J.

    2013-12-01

    Structure of minerals under extreme conditions of high pressure and temperature is very important in Geosciences. The total scattering pair distribution function (PDF) technique using high energy X-ray microbeam to access a large range of scattering vector, e.g. 20Å-1-40Å-1, is an emerging structural analysis method in high pressure research, which allows simultaneous probing of local, intermediate and long-range structure in crystalline, amorphous or complex materials[1-3]. Using high-energy X-rays of 80 keV at X17B3 beamline, National Synchrotron Light Source (NSLS), Brookhaven National Laboratory, PDF measurements has been carried out by users from multiple disciplines [4]. At this AGU meeting, we will present the current status of high-pressure total scattering pair distribution function (PDF) measurements and recent achievements on the availability of high energy X-ray microbeam at X17B3 beamline, NSLS. Accurate X-ray energy calibration is indispensable for X-ray energy-sensitive scattering and diffraction experiments, but there is still a lack of effective methods to precisely calibrate the high energy X-ray beam, because precise energy calibration XAS is problematic due to the lack of suitable X-ray absorption edges at the desired high energy. We have recently proposed an iterative method [5] for a precise and fast X-ray energy calibration over a wide range, including high energy X-ray beam for PDF measurements. Some PDF measurements on the geophysical important materials, such as GeO2 and SiO2 materials, under ambient and high-pressure using diamond anvil cell will be presented. References: 1. Billinge, S.J.L., The atomic pair distribution function: past and present. Zeitschrift für Kristallographie, 2004. 219(3-2004): p. 117-121. 2. Billinge, S.J. and I. Levin, The problem with determining atomic structure at the nanoscale. Science, 2007. 316(5824): p. 561-5. 3. Billinge, S.J.L., et al., Characterisation of amorphous and nanocrystalline molecular

  1. Crystallization and preliminary X-ray studies on the reaction center–light-harvesting 1 core complex from Rhodopseudomonas viridis

    International Nuclear Information System (INIS)

    The reaction center–light-harvesting 1 core complex from R. viridis was crystallized and X-ray diffraction data were collected to 8.0 Å resolution. The reaction center–light-harvesting 1 (RC–LH1) core complex is the photosynthetic apparatus in the membrane of the purple photosynthetic bacterium Rhodopseudomonas viridis. The RC is surrounded by an LH1 complex that is constituted of oligomers of three types of apoproteins (α, β and γ chains) with associated bacteriochlorophyll bs and carotenoid. It has been crystallized by the sitting-drop vapour-diffusion method. A promising crystal diffracted to beyond 8.0 Å resolution. It belonged to space group P1, with unit-cell parameters a = 141.4, b = 136.9, c = 185.3 Å, α = 104.6, β = 94.0, γ = 110.7°. A Patterson function calculated using data between 15.0 and 8.0 Å resolution suggested that the LH1 complex is distributed with quasi-16-fold rotational symmetry around the RC

  2. Diffuse Intracluster Light at Intermediate Redshifts: ICL observations in a X-ray cluster at z=0.29

    CERN Document Server

    Toledo, I; Selman, F; Quintana, H; Giraud, E; Zelaya, P

    2011-01-01

    The diffuse intracluster light (ICL) contains a significant fraction of the total stellar mass in clusters of galaxies, and contributes in roughly equal proportion as the hot intra-cluster medium (ICM) to the total baryon content of clusters. Because of the potential importance of understanding the origin of the ICL in the context of the formation and evolution of structure in the Universe, the field has recently undergone a revival both in the quality and quantity of observational and theoretical investigations. Due to cosmological dimming, the observational work has mostly concentrated on low redshift clusters, but clearly observations at higher redshifts can provide interesting clues about the evolution of the diffuse component. In this paper we present the first results of a program to characterize the ICL of intermediate redshift clusters. We find that at z ~ 0.3, the X-ray cluster RX J0054.0-2823 already has a significant ICL and that the fraction of the total light in the ICL and the brightest cluster ...

  3. Effect of Aberration of Light in X-ray Free Electron Lasers

    CERN Document Server

    Geloni, Gianluca; Saldin, Evgeni

    2015-01-01

    We discuss the physics of a microbunched electron beam kicked by the dipole field of a corrector magnet by describing the kinematics of coherent undulator radiation after the kick. Particle tracking shows that the electron beam direction changes after the kick, while the orientation of the microbunching wavefront stays unvaried. Therefore, electrons motion and wavefront normal have different directions. Coherent radiation emission in a downstream undulator is expected to be dramatically suppressed as soon as the kick angle becomes larger than the divergence of the output radiation. In fact, according to conventional treatments, coherent radiation is emitted along the normal to the microbunching wavefront. Here we show that kinematics predicts a surprising effect. Namely, a description of coherent undulator radiation in the laboratory frame yields the radical notion that, due light aberration, strong coherent radiation is produced along the direction of the kick. We hold a recent FEL study made at the LCLS as ...

  4. The pH induced sol-gel transition in skim milk revisited. a detailed study using time-resolved light and X-ray scattering experiments

    OpenAIRE

    Moitzi, Christian; Menzel, Andreas; Schurtenberger, Peter; Stradner, Anna

    2011-01-01

    We present a detailed study of the evolution of the size, structure and stability of casein micelles upon acidification of skim milk typically applied in yogurt-making processes using a combination of time-resolved light and small-angle X-ray scattering experiments. While most of the available light scattering studies on casein acidification have been restricted to transparent and therefore highly diluted samples, we now profit from a newly developed multiangle 3D light scattering instrument,...

  5. Structure of PEP-PEO block copolymer micelles: Exploiting the complementarity of small-angle X-ray scattering and static light scattering

    DEFF Research Database (Denmark)

    Jensen, Grethe Vestergaard; Shi, Qing; Hernansanz, María J.;

    2011-01-01

    . The present work shows that the same information can be obtained by combining static light scattering (SLS) and small-angle X-ray scattering (SAXS), which provide information on, respectively, large and short length scales. Micelles of a series of block copolymers of poly(ethylene propylene...

  6. Effect of aberration of light in X-ray free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2015-11-15

    We discuss the physics of a microbunched electron beam kicked by the dipole field of a corrector magnet by describing the kinematics of coherent undulator radiation after the kick. Particle tracking shows that the electron beam direction changes after the kick, while the orientation of the microbunching wavefront stays unvaried. Therefore, electrons motion and wavefront normal have different directions. Coherent radiation emission in a downstream undulator is expected to be dramatically suppressed as soon as the kick angle becomes larger than the divergence of the output radiation. In fact, according to conventional treatments, coherent radiation is emitted along the normal to the microbunching wavefront. Here we show that kinematics predicts a surprising effect. Namely, a description of coherent undulator radiation in the laboratory frame yields the radical notion that, due light aberration, strong coherent radiation is produced along the direction of the kick. We hold a recent FEL study made at the LCLS as a direct experimental evidence that coherent undulator radiation can be kicked by an angle of about five times the rms radiation divergence without suppression. We put forward our kinematical description of this experiment.

  7. Discovery of periodic dips in the light curve of GX 13+1: the X-ray orbital ephemeris of the source

    OpenAIRE

    Iaria, R.; Di Salvo, T.; Burderi, L.; Riggio, A.; D'Aì, A.; Robba, N.

    2014-01-01

    The bright low-mass X-ray binary (LMXB) GX 13+1 is one of the most peculiar Galactic binary systems. A periodicity of 24.27 d with a formal statistical error of 0.03 d was observed in its power spectrum density obtained with RXTE All Sky Monitor (ASM) data spanning 14 years. Starting from a recent study, indicating GX 13+1 as a possible dipping source candidate, we systematically searched for periodic dips in the X-ray light curves of GX 13+1 from 1996 up to 2013 using RXTE/ASM, and MAXI data...

  8. Nanoplasma dynamics of single large xenon clusters irradiated with superintense x-ray pulses from the linac coherent light source free-electron laser.

    Science.gov (United States)

    Gorkhover, T; Adolph, M; Rupp, D; Schorb, S; Epp, S W; Erk, B; Foucar, L; Hartmann, R; Kimmel, N; Kühnel, K-U; Rolles, D; Rudek, B; Rudenko, A; Andritschke, R; Aquila, A; Bozek, J D; Coppola, N; Erke, T; Filsinger, F; Gorke, H; Graafsma, H; Gumprecht, L; Hauser, G; Herrmann, S; Hirsemann, H; Hömke, A; Holl, P; Kaiser, C; Krasniqi, F; Meyer, J-H; Matysek, M; Messerschmidt, M; Miessner, D; Nilsson, B; Pietschner, D; Potdevin, G; Reich, C; Schaller, G; Schmidt, C; Schopper, F; Schröter, C D; Schulz, J; Soltau, H; Weidenspointner, G; Schlichting, I; Strüder, L; Ullrich, J; Möller, T; Bostedt, C

    2012-06-15

    The plasma dynamics of single mesoscopic Xe particles irradiated with intense femtosecond x-ray pulses exceeding 10(16)  W/cm2 from the Linac Coherent Light Source free-electron laser are investigated. Simultaneous recording of diffraction patterns and ion spectra allows eliminating the influence of the laser focal volume intensity and particle size distribution. The data show that for clusters illuminated with intense x-ray pulses, highly charged ionization fragments in a narrow distribution are created and that the nanoplasma recombination is efficiently suppressed. PMID:23004284

  9. Re-examination of charge and orbital ordering in lightly doped La1-xSrxMnO3 by X-ray scattering

    International Nuclear Information System (INIS)

    We report on the new synchrotron X-ray scattering results from the re-investigation of charge and orbital ordering in lightly doped La1-xSrxMnO3. The resonant X-ray scattering from forbidden Bragg reflections was observed not only in the ferromagnetic insulating phase, but also in strongly Jahn-Teller distorted regime. Some of characteristic superstructure reflections were also found to show a clear resonant behavior at the Mn K absorption edge. It can be argued that the exact pattern of charge and orbital ordering should be much more complicated

  10. Center for X-Ray Optics, 1986

    International Nuclear Information System (INIS)

    The Center for X-Ray Optics has made substantial progress during the past year on the development of very high resolution x-ray technologies, the generation of coherent radiation at x-ray wavelengths, and, based on these new developments, had embarked on several scientific investigations that would not otherwise have been possible. The investigations covered in this report are topics on x-ray sources, x-ray imaging and applications, soft x-ray spectroscopy, synchrotron radiation, advanced light source and magnet structures for undulators and wigglers

  11. Development of spatially resolved high resolution x-ray spectroscopy for fusion and light-source research

    Science.gov (United States)

    Lu, J.; Hill, K. W.; Bitter, M.; Delgado-Aparicio, L.; Pablant, N. A.; Efthimion, P.; Beiersdorfer, P.; Chen, H.; Widmann, K.; Sanchez del Rio, M.

    2014-09-01

    One dimensional spatially resolved high resolution x-ray spectroscopy with spherically bent crystals and 2D pixelated detectors is an established technique on magnetic confinement fusion (MCF) experiments world wide for Doppler measurements of spatial profiles of plasma ion temperature and flow velocity. This technique is being further developed for diagnosis of High Energy Density Physics (HEDP) plasmas at laser-plasma facilities and synchrotron/x-ray free electron laser (XFEL) facilities. Useful spatial resolution (micron scale) of such small-scale plasma sources requires magnification, because of the finite pixel size of x-ray CCD detectors (13.5 μm). A von-Hamos like spectrometer using spherical crystals is capable of magnification, as well as uniform sagittal focusing across the full x-ray spectrum, and is being tested in laboratory experiments using a tungsten-target microfocus (5-10 μm) x-ray tube and 13-μm pixel x-ray CCD. A spatial resolution better than 10 μm has been demonstrated. Good spectral resolution is indicated by small differences (0.02 - 0.1 eV) of measured line widths with best available published natural line widths. Progress and status of HEDP measurements and the physics basis for these diagnostics are presented. A new type of x-ray crystal spectrometer with a convex spherically bent crystal is also reported. The status of testing of a 2D imaging microscope using matched pairs of spherical crystals with x rays will also be presented. The use of computational x-ray optics codes in development of these instrumental concepts is addressed.

  12. Theoretical analysis of hard x-ray generation by nonperturbative interaction of ultrashort light pulses with a metal

    Directory of Open Access Journals (Sweden)

    Jannick Weisshaupt

    2015-03-01

    Full Text Available The interaction of intense femtosecond pulses with metals allows for generating ultrashort hard x-rays. In contrast to plasma theories, tunneling from the target into vacuum is introduced as electron generation step, followed by vacuum acceleration in the laser field and re-entrance into the target to generate characteristic x-rays and Bremsstrahlung. For negligible space charge in vacuum, the Kα flux is proportional to the incident intensity and the wavelength squared, suggesting a strong enhancement of the x-ray flux by mid-infrared driving pulses. This prediction is in quantitative agreement with experiments on femtosecond Cu Kα generation.

  13. Joint x-ray

    Science.gov (United States)

    X-ray - joint; Arthrography; Arthrogram ... x-ray technologist will help you position the joint to be x-rayed on the table. Once in place, pictures are taken. The joint may be moved into other positions for more ...

  14. Structure of hollow spheres analyzed by X-ray diffraction, transmission electron microscopy, and dynamic light scattering

    International Nuclear Information System (INIS)

    The structural properties of nanoscale Ag, La(OH)3, CuS (covellite), Ag2S (acanthite), and ZnO hollow spheres, massive Ag nanoparticles and In–Ag core–shell nanoparticles with outer diameters between 200 and 400 Å, were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), dynamic light scattering (DLS), and differential sedimentation (DS). Lognormal size distributions of single-crystalline (quasi)spherical nanoparticles are found in our samples by DLS, STEM, DS, and HRTEM. The lattice parameters of the nanomaterials are determined by XRD line–position analysis, while the volume-averaged size and the microstrain are derived by the average-size and strain approximation in the integral breadth method. A new expression is presented in this work to derive the real average outer diameter D-bar of hollow spherical particles. The good agreement between D-bar and the corresponding diameter determined by DLS in the case of Ag and La(OH)3 hollow spheres demonstrates the validity of the approach. The same expression is applied to derive the average wall thickness of CuS and Ag2S hollow spheres as well as for the Ag shell thickness of In–Ag core–shell nanoparticles.

  15. Confirming the 115.5-day periodicity in the X-ray light curve of ULX NGC 5408 X-1

    Institute of Scientific and Technical Information of China (English)

    Xu Han; Tao An; Jun-Yi Wang; Ji-Ming Lin; Ming-Jie Xie; Hai-Guang Xu; Xiao-Yu Hong; Sandor Frey

    2012-01-01

    The Swift/XRT light curve of the ultraluminous X-ray source NGC 5408 X-1 was re-analyzed with two new numerical approaches,the Weighted Wavelet Ztransform and CLEANest,and the results are different from previous studies.Both techniques detected a prominent periodicity with a time scale of 115.5 ± 1.5 days,in excellent agreement with the detection of the same periodicity first reported by Strohmayer.Monte Carlo simulations were employed to test the statisitical confidence of the 115.5-day periodicity,yielding a statistical significance of > 99.98% (or >3.8σ).The robust detection of the 115.5-day quasi-periodic oscillations,if they are due to the orbital motion of the binary,would infer a mass of a few thousand M⊙ for the central black hole,implying there is an intermediate-mass black hole in NGC 5408 X-1.

  16. Phases and phase transitions of polymeric liquid crystals: A high resolution x ray diffraction and light scattering study

    Science.gov (United States)

    Nachaliel, Ehud

    1991-03-01

    Liquid crystal polymers (LCP) were compared with monomeric liquid crystals (MLC) by means of high-resolution x-ray (HIREX) and light scattering (LIS). Both HIREX and LIS were used to study the nematic-smectic(sub a) phase transition of P4.1 polysiloxane; the following critical exponents were determined: nu(sub parallel) = 0.77 +/-0.05; nu(sub normal) = 0.57 +/-0.08; gamma = 1.3 +/-0.10. The bare correlation lengths were found to be: xi(sup 0)(sub parallel) = 3.27 +/-0.08; xi(sup 0)(sub normal)q(sub 0) = 1.09 +/-0.14 which are unusually large in comparison with MLC. LIS experiments confirmed these values and indicated 'cross over' of nu(sub parallel) from 0.77 to 0.53. These results are typical of a system near to a tricritical point. HIREX was used to study the nematic-smectic(sub c) phase transition in C6-polysiloxane; the results were a good fit to Chen and Lubensky's mean field theory but the correlation lengths saturated near the transition to the nematic phase. A study of the smectic(sub a) phase of PA6 polyacrylate, near the transition to the nematic phase, showed that, except very close to the transition, the first and second harmonics of the x-ray structure factor were found to be consistent with the harmonic theory of de Gennes and Caille. This is thought to indicate the importance of anharmonic corrections near the phase transition. Fits to the experimental data yielded the compressibility constant, B and the splay elastic constant, K(sub s). B was found to obey a power law: B varies as t(sup phi) in which phi = 0.82 +/-0.08. In good agreement with theoretical predictions using exponents from the literature, but in disagreement with previous experimental results on MLC's. The splay elastic constant K(sub s) has roughly the same magnitude as in MLC's but tends to decrease by approximately 50% upon approaching the transition from below. This temperature dependence might give further evidence for the importance of anharmonicity in the system. Finally, the

  17. Center for X-ray Optics, 1988

    Energy Technology Data Exchange (ETDEWEB)

    1989-04-01

    This report briefly reviews the following topics: soft-x-ray imaging; reflective optics for hard x-rays; coherent XUV sources; spectroscopy with x-rays; detectors for coronary artery imaging; synchrotron-radiation optics; and support for the advanced light source.

  18. Center for X-ray Optics, 1988

    International Nuclear Information System (INIS)

    This report briefly reviews the following topics: soft-x-ray imaging; reflective optics for hard x-rays; coherent XUV sources; spectroscopy with x-rays; detectors for coronary artery imaging; synchrotron-radiation optics; and support for the advanced light source

  19. Which process will happen in GRB radiation zone based on X-ray flares data, Internal Shock or ICMART?

    Science.gov (United States)

    Jia, Lanwei; Zhang, Bing

    2015-08-01

    If the emission from the central engine ceases abruptly in Gamma-ray burst radiation zone where Internal Shock or ICMART process may happen, then the curvature effect of the relativistic shell will shape the observed light curves. Bright X-ray flares have been detected in the early X-ray light curves of nearly one-half of the burst population, and curvature effect has been invoked to interpret the decay segment of the X-ray flares. So we choose all X-ray flares which display a very neat light curve detected by Swift satellite from 2004 to 2014, and find that the shell in radiation zone still in acceleration, demonstrating ICMART process is happening in radiation zone for our GRB sample.

  20. X-ray pulsar rush in 1998

    International Nuclear Information System (INIS)

    We present recent remarkable topics about discoveries of X-ray pulsars. 1. Pulsations from two Soft Gamma-ray Repeaters: These pulsars have enormously strong magnetic field (B ∼ 1015 G), thus these are called as 'magnetar', new type of X-ray pulsars. 2. New Crab-like pulsars: These discoveries lead to suggesting universality of Crab-like pulsars. 3. An X-ray bursting millisecond pulsar: This is strong evidence for the recycle theory of generating radio millisecond pulsars. 4. X-ray pulsar rush in the SMC: This indicates the younger star formation history in the SMC. (author)

  1. Shallow Decay of X-ray Afterglows in Short GRBs: Energy Injection from a Millisecond Magnetar?

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    With the successful launch of Swift satellite, more and more data of early X-ray afterglows from short gamma-ray bursts have been collected. Some interesting features such as unusual afterglow light curves and unexpected X-ray flares are revealed. Especially, in some cases, there is a flat segment in the X-ray afterglow light curve. Here we present a simplified model in which we believe that the flattening part is due to energy injection from the central engine. We assume that this energy injection arises from the magnetic dipole radiation of a millisecond pulsar formed after the merger of two neutron stars. We check this model with the short GRB 060313. Our numerical results suggest that energy injection from a millisecond magnetar could make part of the X-ray afterglow light curve flat.

  2. Discovery of periodic dips in the light curve of GX 13+1: the X-ray orbital ephemeris of the source

    CERN Document Server

    Iaria, R; Burderi, L; Riggio, A; D'Ai, A; Robba, N R

    2013-01-01

    The bright low-mass X-ray binary (LMXB) GX 13+1 is one of the most peculiar Galactic binary systems. A periodicity of 24.27 d with a formal statistical error of 0.03 d was observed in its power spectrum density obtained with RXTE All Sky Monitor (ASM) data spanning 14 years. Starting from a recent study, indicating GX 13+1 as a possible dipping source candidate, we systematically searched for periodic dips in the X-ray light curves of GX 13+1 from 1996 up to 2013 using RXTE/ASM, and MAXI data to determine for the first time the X-ray orbital ephemeris of GX 13+1. We searched for a periodic signal in the ASM and MAXI light curves, finding a common periodicity of 24.53 d. We folded the 1.3-5 keV and 5-12.1 keV ASM light curves and the 2-4 and 4-10 keV MAXI light curves at the period of 24.53 d finding a periodic dip. To refine the value of the period we used the timing technique dividing the ASM light curve in eight intervals and the MAXI light curve in two intervals, obtaining four and two dip arrival times fr...

  3. An accuracy assessment of photo-ionization cross-section datasets for 1–2 keV x-rays in light elements using PIXE

    International Nuclear Information System (INIS)

    Proton-induced x-ray emission (PIXE) was used to assess the accuracy of the National Institute of Standards and Technology XCOM and FFAST photo-ionization cross-section databases in the low energy region (1–2 keV) for light elements. Characteristic x-ray yields generated in thick samples of Mg, Al and Si in elemental and oxide form, were compared to fundamental parameters computations of the expected x-ray yields; the database for this computation included XCOM attenuation coefficients. The resultant PIXE instrumental efficiency constant was found to differ by 4–6% between each element and its oxide. This discrepancy was traced to use of the XCOM Hartree–Slater photo-electric cross-sections. Substitution of the FFAST Hartree–Slater cross-sections reduced the effect. This suggests that for 1–2 keV x-rays in light element absorbers, the FFAST predictions of the photo-electric cross-sections are more accurate than the XCOM values. (paper)

  4. Systematic Uncertainties in the Spectroscopic Measurements of Neutron-Star Masses and Radii from Thermonuclear X-ray Bursts. III. Absolute Flux Calibration

    OpenAIRE

    Guver, Tolga; Ozel, Feryal; Marshall, Herman; Psaltis, Dimitrios; Guainazzi, Matteo; Diaz-Trigo, Maria

    2015-01-01

    Many techniques for measuring neutron star radii rely on absolute flux measurements in the X-rays. As a result, one of the fundamental uncertainties in these spectroscopic measurements arises from the absolute flux calibrations of the detectors being used. Using the stable X-ray burster, GS 1826-238, and its simultaneous observations by Chandra HETG/ACIS-S and RXTE/PCA as well as by XMM-Newton EPIC-pn and RXTE/PCA, we quantify the degree of uncertainty in the flux calibration by assessing the...

  5. Constraints on the mass and radius of neutron stars from X-ray observations

    OpenAIRE

    Li, Zhaosheng

    2015-01-01

    This article gives a very brief introduction about measuring the mass and radius of neutron star from X-ray observations. The masses and radii of neutron stars can be determined from photospheric radius expansion bursts in low-mass X-ray binaries, X-ray pulse profile modeling in accreting X-ray pulsars, gravitational redshift measurement in low-mass X-ray binaries and thermal X-ray spectral fitting in quiescent low-mass X-ray binaries.

  6. Chest x-ray

    Science.gov (United States)

    Chest radiography; Serial chest x-ray; X-ray - chest ... You stand in front of the x-ray machine. You will be told to hold your breath when the x-ray is taken. Two images are usually taken. You will ...

  7. 5 f -Shell correlation effects in dioxides of light actinides studied by O 1s x-ray absorption and emission spectroscopies and first-principles calculations

    International Nuclear Information System (INIS)

    Soft x-ray emission and absorption spectroscopic data are reported for the O 1s region of a single crystal of UO2, a polycrystalline NpO2 sample, and a single crystal of PuO2. The experimental data are interpreted using first-principles correlated-electron calculations within the framework of the density functional theory with added Coulomb U interaction (DFT+U). A detailed analysis regarding the origin of different structures in the x-ray emission and x-ray absorption spectra is given and the effect of varying the intra-atomic Coulomb interaction-U for the 5 f electrons is investigated. Our data indicate that O 1s x-ray absorption and emission spectroscopies can, in combination with DFT+U calculations, successfully be used to study 5 f -shell Coulomb correlation effects in dioxides of light actinides. The values for the Coulomb U parameter in these dioxides are derived to be in the range of 4–5 eV. (paper)

  8. Sci—Thur PM: Imaging — 03: A novel Čerenkov detector based on air-spaced light guiding taper for megavoltage x-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Teymurazyan, A [Imaging Research, Sunnybrook Health Sciences Centre, Department of Medical Biophysics, University of Toronto, Toronto (Canada); Rowlands, J A [Thunder Bay Regional Research Institute (IBRRI), Thunder Bay (Canada); Department of Radiation Oncology, University of Toronto, Toronto (Canada); Pang, G [Imaging Research, Sunnybrook Health Sciences Centre, Department of Medical Biophysics, University of Toronto, Toronto (Canada); Department of Radiation Oncology, University of Toronto, Toronto (Canada); Odette Cancer Centre, Toronto (Canada); Department of Physics, Ryerson University, Toronto (Canada)

    2014-08-15

    Electronic Portal Imaging Devices (EPIDs) have been used in radiation therapy and are still needed on linear accelerators (Linacs) equipped with kilovoltage cone beam CT (kV-CBCT) or MRI systems. Recently a new concept of a high quantum efficiency (QE) Čerenkov Portal Imaging Device (CPID) for MV x-ray imaging in radiation therapy was introduced. It relies on Čerenkov effect for x-ray detection. The proposed design consisted of a matrix of optical fibres aligned with the incident x-rays and coupled to an active matrix flat panel imager (AMFPI) for image readout. A weakness of such design is that too few Čerenkov light photons reach the AMFPI for each incident x-ray and an AMFPI with an avalanche gain is required. In this work we propose to replace the optical fibers in the CPID with light guides without a cladding layer that are suspended in air. The air between the light guides takes on the role of the cladding layer found in a regular optical fiber. Since air has a significantly lower refractive index, a much superior light collection efficiency is achieved. Our Monte Carlo studies have shown that the modified new CPID has a QE more than an order of magnitude greater than that of current clinical systems and yet a spatial resolution similar to that of current flat-panel based EPIDs. Furthermore it has been demonstrated that the new CPID does not require an avalanche gain in the AMFPI and is quantum noise limited at dose levels corresponding to a single Linac pulse.

  9. Reaction rates of $^{64}$Ge($p,\\gamma$)$^{65}$As and $^{65}$As($p,\\gamma$)$^{66}$Se and the extent of nucleosynthesis in type I X-ray bursts

    CERN Document Server

    Lam, Y H; Parikh, A; Brown, B A; Wang, M; Guo, B; Zhang, Y H; Zhou, X H; Xu, H S

    2015-01-01

    The extent of nucleosynthesis in models of type I X-ray bursts and the associated impact on the energy released in these explosive events are sensitive to nuclear masses and reaction rates around the $^{64}$Ge waiting point. Using a recent high precision mass measurement of $^{65}$As along with large-scale shell model calculations, we have determined new thermonuclear rates of the $^{64}$Ge($p$,$\\gamma$)$^{65}$As and $^{65}$As($p$,$\\gamma$)$^{66}$Se reactions. We examine the impact of available rates for these two reactions through a representative one-zone X-ray burst model. We find that our recommended rates may strongly suppress the flow of abundances toward $A\\approx100$, in sharp contrast to recent work claiming that $^{64}$Ge is not a significant $rp$-process waiting point. Indeed, the summed mass fractions for species with $A > 70$ varies by about factors of 3 or 2 depending upon the adopted $^{64}$Ge($p$,$\\gamma$)$^{65}$As or $^{65}$As($p$,$\\gamma$)$^{66}$Se rates, respectively. Furthermore, the predi...

  10. GRB Redshift determination in the X-ray band

    OpenAIRE

    Campana, Sergio; Ghisellini, Gabriele; Lazzati, Davide; Haardt, Francesco; Covino, Stefano; .

    1999-01-01

    If gamma-ray bursts originate in dense stellar forming regions, the interstellar material can imprint detectable absorption features on the observed X-ray spectrum. Such features can be detected by existing and planned X-ray satellites, as long as the X-ray afterglow is observed after a few minutes from the burst. Detection of these X-ray features will make possible the determination of the redshift of gamma-ray bursts even when their optical afterglows are severely dimmed by extinction.

  11. RXTE/ASM and Swift/BAT Observations of Spectral Transitions in Bright X-ray Binaries in 2005-2010

    OpenAIRE

    Tang, Jing; Yu, Wenfei; Yan, Zhen

    2010-01-01

    We have studied X-ray spectral state transitions that can be seen in the long- term monitoring light curves of bright X-ray binaries from the All-Sky Monitor (ASM) on board the Rossi X-ray Timing Explorer (RXTE) and the Burst Alert Telescope (BAT) on board Swift during a period of five years from 2005 to 2010. We have applied a program to automatically identify the hard-to-soft (H-S) spectral state transitions in the bright X- ray binaries monitored by the ASM and the BAT. In total we identif...

  12. Thoracic spine x-ray

    Science.gov (United States)

    Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... care provider's office. You will lie on the x-ray table in different positions. If the x-ray ...

  13. The link between coherent burst oscillations, burst spectral evolution and accretion state in 4U 1728-34

    CERN Document Server

    Zhang, Guobao; Zamfir, Michael; Cumming, Andrew

    2015-01-01

    Coherent oscillations and the evolution of the X-ray spectrum during thermonuclear X-ray bursts in accreting neutron-star X-ray binaries have been studied intensively but separately. We analysed all the X-ray bursts of the source 4U 1728-34 with the Rossi X-ray Timing Explorer. We found that the presence of burst oscillations can be used to predict the behaviour of the blackbody radius during the cooling phase of the bursts. If a burst shows oscillations, during the cooling phase the blackbody radius remains more or less constant for ~2 - ~8s, whereas in bursts that do not show oscillations the blackbody radius either remains constant for more than ~2 - ~8s or it shows a rapid (faster than ~2s) decrease and increase. Both the presence of burst oscillations and the time-dependent spectral behaviour of the bursts are affected by accretion rate. We also found that the rise time and convexity of the bursts' light curve are different in bursts with and without oscillations in 4U 1728--34. Bursts with oscillations ...

  14. Initial Results and Future Plans for the Soft X-ray Instrument for Materials at the Linac Coherent Light Source (LCLS)

    Science.gov (United States)

    Schlotter, William; Krupin, Oleg; Minitti, Michael; Turner, Joshua

    2012-02-01

    For two years ultrafast high intensity x-ray pulses have been available at the Linac Coherent Light Source, the x-ray free electron laser at the SLAC National Accelerator Laboratory. The soft x-ray instrument (SXR) operates at an energy range from 480eV-2000eV and features a plane grating monochromator as well as a bendable refocusing mirror system. The measured performance of the instrument will be presented as well as the future direction for instrumentation development. [4pt] Acknowledgement: This research was carried out on the SXR Instrument at the Linac Coherent Light Source (LCLS), a division of SLAC National Accelerator Laboratory and an Office of Science user facility operated by Stanford University for the U.S. Department of Energy. The SXR Instrument is funded by a consortium whose membership includes the LCLS, Stanford University through the Stanford Institute for Materials Energy Sciences (SIMES), Lawrence Berkeley National Laboratory (LBNL), University of Hamburg through the BMBF priority program FSP 301, and the Center for Free Electron Laser Science (CFEL).

  15. Chest X-Ray

    Medline Plus

    Full Text Available ... the most commonly performed x-ray exams and use a very small dose of ionizing radiation to ... to your health. While a chest x-ray use a tiny dose of ionizing radiation, the benefit ...

  16. Dental x-rays

    Science.gov (United States)

    X-ray - teeth; Radiograph - dental; Bitewings; Periapical film; Panoramic film ... dentist's office. There are many types of dental x-rays. Some are: Bitewing Periapical Palatal (also called occlusal) ...

  17. X-ray (image)

    Science.gov (United States)

    X-rays are a form of ionizing radiation that can penetrate the body to form an image on ... will be shades of gray depending on density. X-rays can provide information about obstructions, tumors, and other ...

  18. X-ray apparatus

    International Nuclear Information System (INIS)

    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

  19. From 3rd- to 4th-generation light sources: Free-electron lasers in the X-ray range

    International Nuclear Information System (INIS)

    Activities on free-electron laser (FEL) x-ray sources, based on linear accelerators, to produce spatially coherent, ultra-short (∼100 fs) pulses with very high peak brilliance (1028-1032 photons/s/mm2/mrad2/0.1% BW) are summarized. The scientific case includes time-resolved studies of dynamics on sub-ps scales, structural studies by imaging of non-periodic systems, and investigation of high energy-density phenomena such as non-linear x-ray optics and the production of warm dense matter. Examples are presented, with emphasis on the operational facilities, FLASH at DESY, Hamburg and LCLS in Stanford, California, and on the European XFEL project in Hamburg.

  20. The response of silicon PNCCD sensors with aluminium on-chip filter to visible light, UV- and X-ray radiation

    International Nuclear Information System (INIS)

    There are various scientific applications, from astronomical observations to free electron lasers, that make use of X-ray semiconductor detectors like PNCCDs. The PNCCD is a pixelized semiconductor detector for simultaneous X-ray imaging and spectroscopy. For the seven PNCCD cameras of the eROSITA space telescope, a radiation entrance window including an on-chip optical blocking filter has been designed. The blocking filter is a necessity to minimize electron generation by visible light and UV radiation affecting X-ray spectroscopy. A PNCCD with such a blocking filter has not been used so far in astronomy. The following work deals with the analysis of the response of PNCCDs with on-chip filter. This includes the study of photon absorption and emission processes as well as the transport of electrons inside the detector entrance window. Furthermore it comprises the experimental characterization of the detector properties regarding the attenuation of light as well as their X-ray spectral redistribution function and quantum efficiency. With the ability to reveal the involved physical processes, the PNCCD is subject of analysis and measurement device at the same time. In addition to the results of the measurements, simulations of the solid state physics inside the detector are presented. A Geant4 Monte-Carlo code is extended by the treatment of charge loss in the entrance window and is verified by comparison with experimental data. Reproducing the chain of processes from photon absorption to charge collection, this work provides a detailed understanding of the formation of PNCCD spectra. The spectral features observed in the measurements are attributed to their point of origin inside the detector volume and explained by the model. The findings of this work allow high precision analysis of spectra of silicon detectors, e.g. of the eROSITA data, based on the presented detailed spectral response model.

  1. The response of silicon PNCCD sensors with aluminium on-chip filter to visible light, UV- and X-ray radiation

    Energy Technology Data Exchange (ETDEWEB)

    Granato, Stefanie

    2012-10-18

    There are various scientific applications, from astronomical observations to free electron lasers, that make use of X-ray semiconductor detectors like PNCCDs. The PNCCD is a pixelized semiconductor detector for simultaneous X-ray imaging and spectroscopy. For the seven PNCCD cameras of the eROSITA space telescope, a radiation entrance window including an on-chip optical blocking filter has been designed. The blocking filter is a necessity to minimize electron generation by visible light and UV radiation affecting X-ray spectroscopy. A PNCCD with such a blocking filter has not been used so far in astronomy. The following work deals with the analysis of the response of PNCCDs with on-chip filter. This includes the study of photon absorption and emission processes as well as the transport of electrons inside the detector entrance window. Furthermore it comprises the experimental characterization of the detector properties regarding the attenuation of light as well as their X-ray spectral redistribution function and quantum efficiency. With the ability to reveal the involved physical processes, the PNCCD is subject of analysis and measurement device at the same time. In addition to the results of the measurements, simulations of the solid state physics inside the detector are presented. A Geant4 Monte-Carlo code is extended by the treatment of charge loss in the entrance window and is verified by comparison with experimental data. Reproducing the chain of processes from photon absorption to charge collection, this work provides a detailed understanding of the formation of PNCCD spectra. The spectral features observed in the measurements are attributed to their point of origin inside the detector volume and explained by the model. The findings of this work allow high precision analysis of spectra of silicon detectors, e.g. of the eROSITA data, based on the presented detailed spectral response model.

  2. Emphysema diagnosis using X-ray dark-field imaging at a laser-driven compact synchrotron light source

    OpenAIRE

    Schleede, Simone; Meinel, Felix G.; Bech, Martin; Herzen, Julia; Achterhold, Klaus; Potdevin, Guillaume; Malecki, Andreas; Adam-Neumair, Silvia; Thieme, Sven F.; Bamberg, Fabian; Nikolaou, Konstantin; Bohla, Alexander; Yildirim, Ali Ö.; Loewen, Roderick; Gifford, Martin

    2012-01-01

    In early stages of various pulmonary diseases, such as emphysema and fibrosis, the change in X-ray attenuation is not detectable with absorption-based radiography. To monitor the morphological changes that the alveoli network undergoes in the progression of these diseases, we propose using the dark-field signal, which is related to small-angle scattering in the sample. Combined with the absorption-based image, the dark-field signal enables better discrimination between healthy and emphysemato...

  3. Light elements quantitative x-ray microanalysis of thin samples in STEM. Absorption correction using EELS data

    International Nuclear Information System (INIS)

    Quantification of low Z elements like oxygen by energy-dispersive x-ray spectrometry requires x-rays absorption correction even the in the case of thin films analysis in scanning transmission electron microscope. Absorption correction needs the knowledge of the sample local mass thickness. The purpose of this paper is to propose a method which allows the obtainment of the sample local mass thickness and then permits the quantification of all the elements of the sample using the quantification ratio method. Combining electron energy loss spectroscopy measured relative specimen thickness, and x-rays characteristic peaks intensities, we determine with an iterative process the local mass thickness and the absorption corrected elemental weight concentrations. We validate our method with four standard samples (SiO, SiO2, CaSiO3 and Li4SiO4) by the determination of the O/Si atomic ratio. We also ensure the method by analysing a native bioactive glass sample of known composition and of inhomogeneous mass thickness

  4. Minimum X-ray source size for a lamp-post corona in light-bending models for AGN

    CERN Document Server

    Dovciak, Michal

    2015-01-01

    The lamppost model is often used to describe the X-ray source geometry in AGN, where an infinitesimal point source is located on the black hole spin axis. This is especially invoked for Narrow Line Seyfert 1 (NLS1) galaxies, where an extremely broad iron line seen in episodes of low X-ray flux can both be explained by extremely strong relativistic effects as the source approaches the black hole horizon. The most extreme spectrum seen from the NLS1 1H0707-495 requires that the source is less than 1Rg above the event horizon in this geometry. However, the source must also be large enough to intercept sufficient seed photons from the disk to make the hard X-ray Compton continuum which produces the observed iron line/reflected spectrum. We use a fully relativistic ray tracing code to show that this implies that the source must be substantially larger than 1Rg in 1H0707-495 if the disk is the source of seed photons. Hence the source cannot fit as close as 1Rg to the horizon, so the observed spectrum and variabilit...

  5. The X-ray light curve of the massive colliding wind Wolf-Rayet + O binary WR21a

    CERN Document Server

    Gosset, Eric

    2016-01-01

    Our dedicated XMM-Newton monitoring, as well as archival Chandra and Swift datasets, were used to examine the behaviour of the WN5h+O3V binary WR21a at high energies. For most of the orbit, the X-ray emission exhibits few variations. However, an increase in strength of the emission is seen before periastron, following a 1/D relative trend, where D is the separation between both components. This increase is rapidly followed by a decline due to strong absorption as the Wolf-Rayet (WR) comes in front. The fitted local absorption value appears to be coherent with a mass-loss rate of about 1x10^{-5} M_sol/yr for the WR component. However, absorption is not the only parameter affecting the X-ray emission at periastron as even the hard X-ray emission decreases, suggesting a possible collapse of the colliding wind region near to or onto the photosphere of the companion just before or at periastron. An eclipse may appear as another potential scenario, but it would be in apparent contradiction with several lines of evi...

  6. Extra light fermions in E6-inspired models and the 3.5 keV X-ray line signal

    International Nuclear Information System (INIS)

    We propose a scenario in which extra light fermions in an E6-inspired U(1) extension of the standard model constitute the dark matter, as a simple variation of our model for dark radiation presented in 2010. Interestingly, for the light fermions of mass about 7 keV, we naturally obtain a desired mixing angle to explain the recently discovered 3.5 keV X-ray line signal through the radiative decay into active neutrinos and photons with a lifetime in the range of 1027–1028 seconds

  7. Extra light fermions in $E_6$-inspired models and the 3.5 keV X-ray line signal

    CERN Document Server

    Nakayama, Kazunori; Yanagida, Tsutomu T

    2014-01-01

    We propose a scenario in which extra light fermions in an $E_6$-inspired U(1) extension of the standard model constitute the dark matter, as a simple variation of our model for dark radiation presented in 2010. Interestingly, for the light fermions of mass about 7 keV, they radiatively decay into active neutrinos and photons with a lifetime in the range of $10^{27}-10^{28}$ seconds, which naturally explains the recently discovered 3.5 keV X-ray line signal.

  8. Compensating the electron beam energy spread by the natural transverse gradient of laser undulator in all-optical x-ray light sources

    OpenAIRE

    Tong ZHANG; Feng, Chao; Deng, Haixiao; Wang, Dong; Dai, Zhimin; Zhao, Zhentang

    2013-01-01

    All-optical ideas provide a potential to dramatically cut off the size and cost of x-ray light sources to the university-laboratory scale, with the combination of the laser-plasma accelerator and the laser undulator. However, the large longitudinal energy spread of the electron beam from laser-plasma accelerator may hinder the way to high brightness of these all-optical light sources. In this paper, the beam energy spread effect is proposed to be significantly compensated by the natural trans...

  9. X-Rays

    Science.gov (United States)

    X-rays are a type of radiation called electromagnetic waves. X-ray imaging creates pictures of the inside of your ... different amounts of radiation. Calcium in bones absorbs x-rays the most, so bones look white. Fat and ...

  10. 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 ...

  11. X-Ray Imaging

    Science.gov (United States)

    ... Brain Surgery Imaging Clinical Trials Basics Patient Information X-Ray Imaging Print This Page X-ray imaging is perhaps the most familiar type of imaging. Images produced by X-rays are due to the different absorption rates of ...

  12. THE SWIFT/BAT HARD X-RAY TRANSIENT MONITOR

    International Nuclear Information System (INIS)

    The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as fine as 64 s. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the flux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. The primary interface for the BAT transient monitor is a public Web site. Between 2005 February 12 and 2013 April 30, 245 sources have been detected in the monitor, 146 of them persistent and 99 detected only in outburst. Among these sources, 17 were previously unknown and were discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and filtering for the BAT transient monitor and review its sensitivity and exposure. We provide a summary of the source detections and classify them according to the variability of their light curves. Finally, we review all new BAT monitor discoveries. For the new sources that are previously unpublished, we present basic data analysis and interpretations

  13. The Swift-BAT Hard X-Ray Transient Monitor

    Science.gov (United States)

    Krimm, H. A.; Holland, S. T.; Corbet, R. H. D.; Pearlman, A. B.; Romano, P.; Kennea, J. A.; Bloom, J. S.; Barthelmy, S. D.; Baumgartner, W. H.; Cummings, J. R.; Gehrels, N.; Lien, A. Y.; Markwardt, C. B.; Palmer, D. M.; Sakamoto, T.; Stamatikos, M.; Ukwatta, T. N.

    2013-01-01

    The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as fine as 64 s. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the flux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. The primary interface for the BAT transient monitor is a public Web site. Between 2005 February 12 and 2013 April 30, 245 sources have been detected in the monitor, 146 of them persistent and 99 detected only in outburst. Among these sources, 17 were previously unknown and were discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and filtering for the BAT transient monitor and review its sensitivity and exposure.We provide a summary of the source detections and classify them according to the variability of their light curves. Finally, we review all new BAT monitor discoveries. For the new sources that are previously unpublished, we present basic data analysis and interpretations.

  14. The Swift/BAT Hard X-ray Transient Monitor

    Science.gov (United States)

    Krimm, H. A.; Holland, S. T.; Corbet, R.H.D.; Pearlman, A. B.; Romano, P.; Kennea, J. A.; Bloom, J. S.; Barthelmy, S. D.; Baumgartner, W. H.; Cummings, J. R.; Gehrels, N.; Lien, A. Y.; Markwardt, C. B.; Palmer, D. M.; Sakamoto, T.; Stamatikos, M.; Ukwatta, N.

    2013-01-01

    The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as ne as 64 seconds. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the ux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. The primary interface for the BAT transient monitor is a public web page. Since 2005 February, 242 sources have been detected in the monitor, 149 of them persistent and 93 detected only in outburst. Among these sources, 16 were previously unknown and discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and ltering for the BAT transient monitor and review its sensitivity and exposure. We provide a summary of the source detections and classify them according to the variability of their light curves. Finally, we review all new BAT monitor discoveries and present basic data analysis and interpretations for those sources with previously unpublished results.

  15. Gamma Ray Burst engine activity within the quark nova scenario: Prompt emission, X-ray Plateau, and sharp drop-off

    OpenAIRE

    Staff, Jan; Niebergal, Brian; Ouyed, Rachid

    2007-01-01

    We present a three-stage model for a long GRB inner engine to explain the prompt gamma ray emission, and interpret recent Swift satellite observations of early X-ray afterglow plateaus followed by a sharp drop off or a shallow power law decay. The three stages involves a neutron star phase, a quark star (QS) and a black hole phase as described in Staff et al. (2007). We find that the QS stage allows for more energy to be extracted from neutron star to QS conversion as well as from ensuing acc...

  16. Quantitative three-dimensional analysis of poly (lactic-co-glycolic acid) microsphere using hard X-ray nano-tomography revealed correlation between structural parameters and drug burst release.

    Science.gov (United States)

    Huang, Xiaozhou; Li, Na; Wang, Dajiang; Luo, Yuyan; Wu, Ziyu; Guo, Zhefei; Jin, Qixing; Liu, Zhuying; Huang, Yafei; Zhang, Yongming; Wu, Chuanbin

    2015-08-10

    The objective of this study was to investigate the use of transmission hard X-ray nano-computed-tomography (nano-CT) for characterization of the pore structure and drug distribution in poly (lactic-co-glycolic acid) (PLGA) microspheres encapsulating bovine serum albumin and to study the correlation between drug distribution and burst release. The PLGA microspheres were fabricated using a double-emulsion method. The results of pore structure analysis accessed with nano-CT were compared with those acquired by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Surface pore interconnectivity and surface protein interconnectivity were obtained using combined nano-CT and pixel analysis. The correlation between surface protein interconnectivity with the initial burst release across various tested formulations was also analyzed. The size, shape, and distribution of the pores and protein could be clearly observed in the whole microsphere using nano-CT, whereas only the sectional information was observed using SEM or CLSM. Interconnected pores and surface connected pores could be clearly distinguished in nano-CT, which enables the quantitative analysis of surface pore interconnectivity and surface protein interconnectivity. The surface protein interconnectivity in different formulations correlated well with the burst release at 5-10h. Nano-CT provided a nondestructive, high-resolution, and three-dimensional analysis method to characterize the porous microsphere. PMID:25951620

  17. Cryogenic coherent X-ray diffraction imaging of biological samples at SACLA: a correlative approach with cryo-electron and light microscopy.

    Science.gov (United States)

    Takayama, Yuki; Yonekura, Koji

    2016-03-01

    Coherent X-ray diffraction imaging at cryogenic temperature (cryo-CXDI) allows the analysis of internal structures of unstained, non-crystalline, whole biological samples in micrometre to sub-micrometre dimensions. Targets include cells and cell organelles. This approach involves preparing frozen-hydrated samples under controlled humidity, transferring the samples to a cryo-stage inside a vacuum chamber of a diffractometer, and then exposing the samples to coherent X-rays. Since 2012, cryo-coherent diffraction imaging (CDI) experiments have been carried out with the X-ray free-electron laser (XFEL) at the SPring-8 Ångstrom Compact free-electron LAser (SACLA) facility in Japan. Complementary use of cryo-electron microscopy and/or light microscopy is highly beneficial for both pre-checking samples and studying the integrity or nature of the sample. This article reports the authors' experience in cryo-XFEL-CDI of biological cells and organelles at SACLA, and describes an attempt towards reliable and higher-resolution reconstructions, including signal enhancement with strong scatterers and Patterson-search phasing. PMID:26919369

  18. New method for determining temperature and emission measure during solar flares from light curves of soft X-ray line fluxes

    International Nuclear Information System (INIS)

    I describe a new property of soft X-ray line fluxes observed during the decay phase of solar flares and a technique for using this property to determine the plasma temperature and emission measure as functions of time. The soft X-ray line fluxes analyzed in this paper were observed during the decay phase of the 1980 November 5 flare by the X-Ray Polychromator (XRP) instrument on board the Solar Maximum Mission (SMM). The resonance, intercombination, and forbidden lines of Ne IX, Mg XI, Si XIII, S XV, Ca XIX, and Fe XXV, as well as the Lyman-α line of O VIII and the resonance lines of Fe XIX, were observed. The rates at which the observed line fluxes decayed were not constant. For all but the highest temperature lines observed, the rate changed abruptly, causing the fluxes to fall at a more rapid rate later in the flare decay. These changes occurred at earlier times for lines formed at higher temperatures. This behavior is proposed to be due to the decreasing temperature of the flare plasma tracking the rise and subsequent fall of each line emissivity function. This explanation is used to empirically model the observed light curves and to estimate the temperature and the change in emission measure of the plasma as a function of time during the decay phase. Estimates are made of various plasma parameters based on the model results

  19. Point spread function and centroiding accuracy measurements with the JET-X mirror and MOS CCD detector of the Swift gamma ray burst explorer's X-ray telescope

    CERN Document Server

    Ambrosi, R M; Hutchinson, I B; Willingale, R; Wells, A; Short, A D T; Campana, S; Citterio, O; Tagliaferri, G; Burkert, W; Bräuninger, H

    2002-01-01

    The optical components of the Swift X-ray telescope (XRT) are already developed items. They are the flight spare X-ray mirror from the JET-X/Spectrum-X program and an MOS CCD (CCD22) of the type currently operating in orbit as part of the EPIC focal plane camera on XMM-Newton (SPIE 4140 (2000) 64). The JET-X mirrors were first calibrated at the Max Planck Institute for Extraterrestrial Physics' (MPE) Panter facility, Garching, Germany in 1996 (SPIE 2805 (1996) 56; SPIE 3114 (1997) 392). Half-energy widths of 16 arcsec at 1.5 keV were confirmed for the two flight mirrors and the flight spare. The calibration of the flight spare was repeated at Panter in July 2000 in order to establish whether any changes had occurred during the 4 yr that the mirror had been in storage at the OAB, Milan, Italy. The results reported in this paper confirm that the resolution of the JET-X mirrors has remained stable over this storage period. In an extension of this test program, the flight spare EPIC camera was installed at the fo...

  20. The Swift X-ray Telescope

    Science.gov (United States)

    Hill, J. E.; Burrows, D. N.; Nousek, J. A.; Wells, A.; Turner, M.; Willingale, R.; Holland, A.; Citterio, O.; Chincarini, G.; Campana, S.; Tagliaferri, G.; Swift XRT Team

    1999-12-01

    The Swift Gamma Ray Burst Explorer will be launched in 2003 to observe hundreds of gamma ray bursts per year and study their X-ray and optical afterglows, using a multiwavelength complement of three instruments: a wide-field Burst Alert Telescope (BAT), an X-Ray Telescope (XRT), and a UV/Optical Telescope (UVOT). The XRT is designed to study X-ray counterparts of the gamma ray bursts and their afterglows, beginning 20--70 s from the time of the burst, and continuing for days or weeks. The XRT utilizes a superb mirror set built for JET-X (Citterio et al. 1996) and a state-of-the-art XMM/EPIC CCD detector to provide a sensitive broad-band (0.2-10 keV) X-ray imager with effective area of 110 cm2 at 1.5 keV, field of view of 23.6 x 23.6 arcminutes, and angular resolution of 15 arcsec HPD. The sensitivity is 2 x 10-14 erg cm-2 s-1 in 104 seconds. The telescope electronics will be designed to provide automated source detection and position reporting, with a position good to 2.5 arcseconds transmitted to the ground within two minutes of the burst detection. The XRT will operate in an auto-exposure mode, adjusting the CCD readout mode automatically to optimize the science return for each frame as the source fades. The XRT will measure spectra and lightcurves of the GRB afterglow beginning within about a minute after the burst and will follow each burst until it fades from view, typically monitoring 2-3 ``old'' bursts at a time while waiting for a new burst to be detected. This work is supported at Penn State by NASA grant NAG5-8401 and at Leicester University by funding from PPARC.

  1. 1SXPS: A Deep Swift X-Ray Telescope Point Source Catalog with Light Curves and Spectra

    Science.gov (United States)

    Evans, P. A.; Osborne, J. P.; Beardmore, A. P.; Page, K. L.; Willingale, R.; Mountford, C. J.; Pagani, C.; Burrows, D. N.; Kennea, J. A.; Perri, M.; Tagliaferri, G.; Gehrels, N.

    2013-01-01

    We present the 1SXPS (Swift-XRT point source) catalog of 151,524 X-ray point sources detected by the Swift-XRT in 8 yr of operation. The catalog covers 1905 sq deg distributed approximately uniformly on the sky. We analyze the data in two ways. First we consider all observations individually, for which we have a typical sensitivity of approximately 3 × 10(exp -13) erg cm(exp -2) s(exp -1) (0.3-10 keV). Then we co-add all data covering the same location on the sky: these images have a typical sensitivity of approximately 9 × 10(exp -14) erg cm(exp -2) s(exp -1) (0.3-10 keV). Our sky coverage is nearly 2.5 times that of 3XMM-DR4, although the catalog is a factor of approximately 1.5 less sensitive. The median position error is 5.5 (90% confidence), including systematics. Our source detection method improves on that used in previous X-ray Telescope (XRT) catalogs and we report greater than 68,000 new X-ray sources. The goals and observing strategy of the Swift satellite allow us to probe source variability on multiple timescales, and we find approximately 30,000 variable objects in our catalog. For every source we give positions, fluxes, time series (in four energy bands and two hardness ratios), estimates of the spectral properties, spectra and spectral fits for the brightest sources, and variability probabilities in multiple energy bands and timescales.

  2. 1SXPS: A DEEP SWIFT X-RAY TELESCOPE POINT SOURCE CATALOG WITH LIGHT CURVES AND SPECTRA

    International Nuclear Information System (INIS)

    We present the 1SXPS (Swift-XRT point source) catalog of 151,524 X-ray point sources detected by the Swift-XRT in 8 yr of operation. The catalog covers 1905 deg2 distributed approximately uniformly on the sky. We analyze the data in two ways. First we consider all observations individually, for which we have a typical sensitivity of ∼3 × 10–13 erg cm–2 s–1 (0.3-10 keV). Then we co-add all data covering the same location on the sky: these images have a typical sensitivity of ∼9 × 10–14 erg cm–2 s–1 (0.3-10 keV). Our sky coverage is nearly 2.5 times that of 3XMM-DR4, although the catalog is a factor of ∼1.5 less sensitive. The median position error is 5.''5 (90% confidence), including systematics. Our source detection method improves on that used in previous X-ray Telescope (XRT) catalogs and we report >68, 000 new X-ray sources. The goals and observing strategy of the Swift satellite allow us to probe source variability on multiple timescales, and we find ∼30, 000 variable objects in our catalog. For every source we give positions, fluxes, time series (in four energy bands and two hardness ratios), estimates of the spectral properties, spectra and spectral fits for the brightest sources, and variability probabilities in multiple energy bands and timescales

  3. Investigation of the interaction of high intensity laser light with solids and hot plasma using X-ray spectroscopic technique

    International Nuclear Information System (INIS)

    This work investigates the properties of high power laser-produced plasmas by developing and applying x-ray spectroscopic methods which utilize spatial resolution. The shadow techniques which were developed in this work yield a high spatial resolution of 5-15μm together with an adequate X-ray spectral resolution for single shots of laser power flux of 2.1013W/cm-2. The intensity distribution in the source is calculated from the partial shadow by numerical differentiation. The main advantage of the present method is the ability to obtain spatial information simultaneously for strong and weak spectral lines for a single shot of medium power laser. Plasma parameters were derived from H-like and He-like lines and their inner-shell satellites, which were obtained from Mg, Al and Si targets. Using shadow techniques, the sizes of the emitting regions of the various spectral lines were measured; the spatial variation of the ionization stage, the electron temperature and density were investigated. A constant electron temperature of (250+-50)eV and electron density scale-length of about 50μm were derived for an expanding plasma. An experimental investigation of the possible origin and the mechanisms responsible for the Ksub(α) radiation in laser-produced plasma was carried out. It is shown that the Ksub(α) radiation was generated by fast suprathermal electrons and originated inside the target behind the interaction zone of the shock and heat waves. Energy penetration depth and hot plasma expansion were tested by using multilayer targets, thin foils and achieving a two-dimensional spatially resolved X-ray Al spectrum. (B.G.)

  4. LIGHT SOURCE: Optics for the lattice of the compact storage ring for a Compton X-ray source

    Science.gov (United States)

    Yu, Pei-Cheng; Wang, Yu; Shen, Xiao-Zhe; Huang, Wen-Hui; Yan, Li-Xin; Du, Ying-Chao; Li, Ren-Kai; Tang, Chuan-Xiang

    2009-06-01

    We present two types of optics for the lattice of a compact storage ring for a Compton X-ray source. The optics design for different operation modes of the storage ring are discussed in detail. For the pulse mode optics, an IBS-suppression scheme is applied to optimize the optics for lower IBS emittance growth rate; as for the steady mode, the method to control momentum compact factor is adopted [Gladkikh P, Phys. Rev. ST Accel. Beams 8, 050702] to obtain stability of the electron beam.

  5. The X-ray light curve of the massive colliding wind Wolf-Rayet + O binary WR21a

    OpenAIRE

    Gosset, Eric; Nazé, Yaël

    2016-01-01

    Our dedicated XMM-Newton monitoring, as well as archival Chandra and Swift datasets, were used to examine the behaviour of the WN5h+O3V binary WR 21a at high energies. For most of the orbit, the X-ray emission exhibits few variations. However, an increase in strength of the emission is seen before periastron, following a 1 /D relative trend, where D is the separation between both components. This increase is rapidly followed by a decline due to strong absorption as the Wolf-Rayet (WR) comes i...

  6. How Long does a Burst Burst?

    CERN Document Server

    Zhang, Bin-Bin; Murase, Kohta; Connaughton, Valerie; Briggs, Michael S

    2013-01-01

    Several gamma-ray bursts (GRBs) last much longer (~ hours) in gamma-rays than typical long GRBs (~ minutes), and recently it was proposed that these "ultra-long GRBs" may form a distinct population, probably with a different (e.g. blue supergiant) progenitor than typical GRBs. However, Swift observations have suggested that many GRBs have extended central engine activities manifested as flares and internal plateaus in X-rays. We perform a comprehensive study on a large sample of Swift GRBs with XRT observations to investigate GRB central engine activity duration and to check whether ultra-long GRBs are special. We define burst duration t_{burst} based on both gamma-ray and X-ray light curves rather than using gamma-ray observations only. We show that the distribution of t_{burst} peaks at ~ 320s for the entire sample, with 17.6% GRBs having t_{burst} > 10^3 s and 5.4% GRBs having t_{burst} > 10^4 s. The distribution shows a tail at the long t_{burst} end. The existence of a separate population is not ruled ou...

  7. Optical and Infrared Light Curves of the Eclipsing X-ray Binary V395 Car = 2S 0921-630

    CERN Document Server

    Ashcraft, Teresa A; Robinson, Edward L

    2012-01-01

    We present results of optical and infrared photometric monitoring of the eclipsing low-mass X-ray binary V395 Car (2S 0921-630). Our observations reveal a clear, repeating orbital modulation with an amplitude of about one magnitude in B, and V and a little less in J. Combining our data with archival observations spanning about 20 years, we derive an updated ephemeris with orbital period 9.0026+/-0.0001d. We attribute the modulation to a combination of the changing aspect of the irradiated face of the companion star and eclipses of the accretion disk around the neutron star. Both appear to be necessary as a secondary eclipse of the companion star is clearly seen. We model the B, V, and J lightcurves using a simple model of an accretion disk and companion star and find a good fit is possible for binary inclinations of 82.2+/-1.0 degrees. We estimate the irradiating luminosity to be about 8x10^35 erg/s, in good agreement with X-ray constraints.

  8. 7 Å Resolution in Protein 2-Dimentional-Crystal X-Ray Diffraction at Linac Coherent Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Pedrini, Bill; Tsai, Ching-Ju; Capitani, Guido; Padeste, Celestino; Hunter, Mark; Zatsepin, Nadia A.; Barty, Anton; Benner, Henry; Boutet, Sebastien; Feld, Geoffrey K.; Hau-Riege, Stefan; Kirian, Rick; Kupitz, Christopher; Messerschmidt, Marc; Ogren, John I.; Pardini, Tommaso; Segelke, Brent; Williams, Garth J.; Spence , John C.; Abela, Rafael; Coleman, Matthew A.; Evans, James E.; Schertler, Gebhard; Frank, Matthias; Li, Xiao-Dan

    2014-06-09

    Membrane proteins arranged as two-dimensional (2D) crystals in the lipid en- vironment provide close-to-physiological structural information, which is essential for understanding the molecular mechanisms of protein function. X-ray diffraction from individual 2D crystals did not represent a suitable investigation tool because of radiation damage. The recent availability of ultrashort pulses from X-ray Free Electron Lasers (X-FELs) has now provided a mean to outrun the damage. Here we report on measurements performed at the LCLS X-FEL on bacteriorhodopsin 2D crystals mounted on a solid support and kept at room temperature. By merg- ing data from about a dozen of single crystal diffraction images, we unambiguously identified the diffraction peaks to a resolution of 7 °A, thus improving the observable resolution with respect to that achievable from a single pattern alone. This indicates that a larger dataset will allow for reliable quantification of peak intensities, and in turn a corresponding increase of resolution. The presented results pave the way to further X-FEL studies on 2D crystals, which may include pump-probe experiments at subpicosecond time resolution.

  9. 1SXPS: A deep Swift X-ray Telescope point source catalog with light curves and spectra

    CERN Document Server

    Evans, P A; Beardmore, A P; Page, K L; Willingale, R; Mountford, C J; Pagani, C; Burrows, D N; Kennea, J A; Perri, M; Tagliaferri, G; Gehrels, N

    2013-01-01

    We present the 1SXPS (Swift-XRT Point Source) catalog of 151,524 X-ray point-sources detected by the Swift-XRT in 8 years of operation. The catalog covers 1905 square degrees distributed approximately uniformly on the sky. We analyze the data in two ways. First we consider all observations individually, for which we have a typical sensitivity of ~3e-13 erg/cm2/s (0.3--10 keV). Then we co-add all data covering the same location on the sky: these images have a typical sensitivity of ~9e-14 erg/cm2/s (0.3--10 keV). Our sky coverage is nearly 2.5 times that of 3XMM-DR4, although the catalog is a factor of ~1.5 less sensitive. The median position error is 5.5" (90% confidence), including systematics. Our source detection method improves on that used in previous XRT catalogs and we report >68,000 new X-ray sources. The goals and observing strategy of the Swift satellite allow us to probe source variability on multiple timescales, and we find ~30,000 variable objects in our catalog. For every source we give position...

  10. Monte Carlo simulation of a quantum noise limited Čerenkov detector based on air-spaced light guiding taper for megavoltage x-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Teymurazyan, A. [Imaging Research, Sunnybrook Health Sciences Centre, Department of Medical Biophysics, University of Toronto, Toronto M4N 3M5 (Canada); Rowlands, J. A. [Imaging Research, Sunnybrook Health Sciences Centre, Department of Medical Biophysics, University of Toronto, Toronto M4N 3M5 (Canada); Thunder Bay Regional Research Institute (TBRRI), Thunder Bay P7A 7T1 (Canada); Department of Radiation Oncology, University of Toronto, Toronto M5S 3E2 (Canada); Pang, G., E-mail: geordi.pang@sunnybrook.ca [Imaging Research, Sunnybrook Health Sciences Centre, Department of Medical Biophysics, University of Toronto, Toronto M4N 3M5 (Canada); Department of Radiation Oncology, University of Toronto, Toronto M5S 3E2 (Canada); Odette Cancer Centre, Toronto M4N 3M5 (Canada); Department of Physics, Ryerson University, Toronto M5B 2K3 (Canada)

    2014-04-15

    Purpose: Electronic Portal Imaging Devices (EPIDs) have been widely used in radiation therapy and are still needed on linear accelerators (Linacs) equipped with kilovoltage cone beam CT (kV-CBCT) or MRI systems. Our aim is to develop a new high quantum efficiency (QE) Čerenkov Portal Imaging Device (CPID) that is quantum noise limited at dose levels corresponding to a single Linac pulse. Methods: Recently a new concept of CPID for MV x-ray imaging in radiation therapy was introduced. It relies on Čerenkov effect for x-ray detection. The proposed design consisted of a matrix of optical fibers aligned with the incident x-rays and coupled to an active matrix flat panel imager (AMFPI) for image readout. A weakness of such design is that too few Čerenkov light photons reach the AMFPI for each incident x-ray and an AMFPI with an avalanche gain is required in order to overcome the readout noise for portal imaging application. In this work the authors propose to replace the optical fibers in the CPID with light guides without a cladding layer that are suspended in air. The air between the light guides takes on the role of the cladding layer found in a regular optical fiber. Since air has a significantly lower refractive index (∼1 versus 1.38 in a typical cladding layer), a much superior light collection efficiency is achieved. Results: A Monte Carlo simulation of the new design has been conducted to investigate its feasibility. Detector quantities such as quantum efficiency (QE), spatial resolution (MTF), and frequency dependent detective quantum efficiency (DQE) have been evaluated. The detector signal and the quantum noise have been compared to the readout noise. Conclusions: Our studies show that the modified new CPID has a QE and DQE more than an order of magnitude greater than that of current clinical systems and yet a spatial resolution similar to that of current low-QE flat-panel based EPIDs. Furthermore it was demonstrated that the new CPID does not require an

  11. Bowen blend echo-tomography of low mass X-ray binaries

    CERN Document Server

    Muñoz-Darias, T; Casares, J; Cornelisse, R; Dhillon, V S; Marsh, T R; Steeghs, D; O'Brien, K; Charles, P A; Still, M

    2007-01-01

    We present simultaneous high time resolution (1-10 Hz) X-ray and optical observations of the persistent LMXBs Sco X-1 and V801 Ara(=4U 1636-536). In the case of Sco X-1 we find that the Bowen/HeII emission lags the X-ray light-curves with a light travel time of ~11-16s which is consistent with reprocessing in the donor star. We also present the detection of three correlated X-ray/optical bursts in V801 ara. Although this latter project is still in progress our preliminary results obtained by subtracting the Continuum light-curve from the Bowen/HeII data provide evidence of orbital phase dependent echoes from the companion star.

  12. The Swift/BAT Hard X-ray Transient Monitor

    CERN Document Server

    Krimm, Hans A; Corbet, Robin H D; Perlman, Aaron B; Romano, Patrizia; Kennea, Jamie A; Bloom, Joshua S; Barthelmy, Scott D; Baumgartner, Wayne H; Cummings, James R; Gehrels, Neil; Lien, Amy Y; Markwardt, Craig B; Palmer, David M; Sakamoto, Taka; Stamatikos, Michael; Ukwatta, Tilan N

    2013-01-01

    The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as fine as 64 seconds. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the flux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. The primary interface for the BAT transient monitor is a public web page. Between 2005 February 12 and 2013 April 30, 245 sources have been detected in the monitor, 146 of them persistent and 99 detected only in outburst. Among these sources, 17 were previously unknown and were discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and filtering for the BAT transient monitor and review its sensitivity ...

  13. Synthetic off-axis light curves for short gamma-ray bursts

    CERN Document Server

    van Eerten, H J

    2011-01-01

    We present results for a large number of short gamma-ray burst (SGRB) afterglow light curve calculations. All calculations were done by combining high resolution twodimensional relativistic hydrodynamics simulations using RAM with a synchrotron radiation code. Results were obtained for different jet energies, circumburst medium densities, jet angles and observer angles and observer frequencies from low radio (75 MHz) to X-ray (1.5 keV). We summarize the light curves through smooth power law fits with up to three breaks, covering jet breaks for small observer angles, the rising phase for large observer angles and the rise and decay of the counterjet. All light curve data are publicly available via http://cosmo.nyu.edu/afterglowlibrary . The data can be used for model fits to currently available observational data and as an aid for predictions of observations by future telescopes such as LOFAR or SKA and will benefit indirectly the study of neutron star mergers using different channels, such as gravitational wa...

  14. Verification of Short-Term Predictions of Solar Soft X-ray Bursts for the Maximum Phase (2000-2001) of Solar Cycle 23

    Institute of Scientific and Technical Information of China (English)

    Cui-Lian Zhu; Jia-Long Wang

    2003-01-01

    We present a verification of the short-term predictions of solar Xray bursts for the maximum phase (2000-2001) of Solar Cycle 23, issued by two prediction centers. The results are that the rate of correct predictions is about equal for RWC-China and WWA; the rate of too high predictions is greater for RWC-China than for WWA, while the rate of too low predictions is smaller for RWC-China than for WWA.

  15. Unveiling the hard X-ray spectrum from the "burst-only" source SAX J1753.5-2349 in outburst

    CERN Document Server

    Del Santo, Melania; Romano, Patrizia; Bazzano, Angela; Wijnands, Rudy; Degenaar, Nathalie; Mereghetti, Sandro

    2010-01-01

    Discovered in 1996 by BeppoSAX during a single type-I burst event, SAX J1753.5-2349 was classified as "burst-only" source. Its persistent emission, either in outburst or in quiescence, had never been observed before October 2008, when SAX J1753.5-2349 was observed for the first time in outburst. Based on INTEGRAL observations,we present here the first high-energy emission study (above 10 keV) of a so-called "burst-only". During the outburst the SAX J1753.5-2349 flux decreased from 10 to 4 mCrab in 18-40 keV, while it was found being in a constant low/hard spectral state. The broad-band (0.3-100 keV) averaged spectrum obtained by combining INTEGRAL/IBIS and Swift/XRT data has been fitted with a thermal Comptonisation model and an electron temperature >24 keV inferred. However, the observed high column density does not allow the detection of the emission from the neutron star surface. Based on the whole set of observations of SAX J1753.5-2349, we are able to provide a rough estimate of the duty cycle of the sys...

  16. X-Ray Polarimetry

    OpenAIRE

    Kaaret, Philip

    2014-01-01

    We review the basic principles of X-ray polarimetry and current detector technologies based on the photoelectric effect, Bragg reflection, and Compton scattering. Recent technological advances in high-spatial-resolution gas-filled X-ray detectors have enabled efficient polarimeters exploiting the photoelectric effect that hold great scientific promise for X-ray polarimetry in the 2-10 keV band. Advances in the fabrication of multilayer optics have made feasible the construction of broad-band ...

  17. Visualizing Cell Architecture and Molecular Location Using Soft X-Ray Tomography and Correlated Cryo-Light Microscopy

    Science.gov (United States)

    McDermott, Gerry; Le Gros, Mark A.; Larabell, Carolyn A.

    2012-05-01

    Living cells are structured to create a range of microenvironments that support specific chemical reactions and processes. Understanding how cells function therefore requires detailed knowledge of both the subcellular architecture and the location of specific molecules within this framework. Here we review the development of two correlated cellular imaging techniques that fulfill this need. Cells are first imaged using cryogenic fluorescence microscopy to determine the location of molecules of interest that have been labeled with fluorescent tags. The same specimen is then imaged using soft X-ray tomography to generate a high-contrast, 3D reconstruction of the cells. Data from the two modalities are then combined to produce a composite, information-rich view of the cell. This correlated imaging approach can be applied across the spectrum of problems encountered in cell biology, from basic research to biotechnological and biomedical applications such as the optimization of biofuels and the development of new pharmaceuticals.

  18. LIGHT SOURCE: RF deflecting cavity for bunch length measurement in Tsinghua Thomson scattering X-ray source

    Science.gov (United States)

    Shi, Jia-Ru; Chen, Huai-Bi; Tang, Chuan-Xiang; Huang, Wen-Hui; Du, Ying-Chao; Zheng, Shu-Xin; Ren, Li

    2009-06-01

    An RF deflecting cavity used for bunch length measurement has been designed and fabricated at Tsinghua University for the Thomson Scattering X-Ray Source. The cavity is a 2856 MHz, π-mode, 3-cell standing-wave cavity, to diagnose the 3.5 MeV beam produced by photocathode electron gun. With a larger power source, the same cavity will again be used to measure the accelerated beam with energy of 50 MeV before colliding with the laser pulse. The RF design using MAFIA for both the cavity shape and the power coupler is reviewed, followed by presenting the fabrication procedure and bench measurement results of two cavities.

  19. Relative responses of an X-ray-resistant hybrid cell-line and its parent line to X-irradiation, ultraviolet light, actinomycin D and cordycepin

    International Nuclear Information System (INIS)

    Using colony formation as an assay, a rat-mouse hybrid cell-line (HD1) and one of its parent lines (H4) have been studied as to their abilities to survive exposure to ionizing radiation, ultraviolet light, and the drugs actinomycin D and cordycepin. HD1 cells were more resistant than H4 to ionizing radiation, actinomycin D and cordycepin. Both cell lines responded similarly to ultraviolet light. When both cell-lines were co-treated with actinomycin D or cordycepin, the toxic effect of ionizing radiation was enhanced, whereas that of ultraviolet light (U.V.L.) was unchanged. The data suggest that RNA synthesis is more important immediately after irradiation with X-rays than with U.V.L. and that cells resistant to the toxic effect of ionizing radiation are also resistant to the toxicity induced by inhibitors of RNA synthesis. (author)

  20. Light speed variation from gamma ray burst GRB 160509A

    CERN Document Server

    Xu, Haowei

    2016-01-01

    It is postulated in Einstein's relativity that the speed of light in vacuum is a constant for all observers. However, the effect of quantum gravity could bring an energy dependence of light speed. Even a tiny speed variation, when amplified by the cosmological distance, may be revealed by the observed time lags between photons with different energies from astrophysical sources. From the newly detected long gamma ray burst GRB~160509A, we find evidence to support the prediction for a linear form modification of light speed in cosmological space.

  1. Light speed variation from gamma ray burst GRB 160509A

    Science.gov (United States)

    Xu, Haowei; Ma, Bo-Qiang

    2016-09-01

    It is postulated in Einstein's relativity that the speed of light in vacuum is a constant for all observers. However, the effect of quantum gravity could bring an energy dependence of light speed. Even a tiny speed variation, when amplified by the cosmological distance, may be revealed by the observed time lags between photons with different energies from astrophysical sources. From the newly detected long gamma ray burst GRB 160509A, we find evidence to support the prediction for a linear form modification of light speed in cosmological space.

  2. X-ray imaging by partially coherent synchrotron light. Application to metallic alloys, tooth dentin and natural rock

    Energy Technology Data Exchange (ETDEWEB)

    Zabler, Simon Andreas

    2007-10-09

    The hard spectrum which is available on the BAMline at Berlin's synchrotron BESSY offers the rare opportunity to perform high-resolution X-ray imaging experiments with a partially coherent beam. This thesis work reports on the development of a new tomography system, including Fresnel-propagated imaging, and its application to three specific materials science problems from the fields of engineering materials, biology and earth science. Static and dynamic 2D and 3D images were recorded from a variety of aluminum-based alloys. Coarsening of particle agglomerates (at high solid volume fraction) in liquid solution, as well as rheological properties of semi-solid alloys are thus characterized. Dentin is characterized by a quasi-parallel arrangement of micrometer-sized tubules. This work shows how high-resolution 3D images of water-immersed tooth dentin are recorded, and detailed simulations of the optical wave propagation reveal that Fresnel-images contain additional information about the dense cuff of peritubular dentin surrounding the tubules. The cuff thickness can be extrapolated from the interference fringes that form the propagated images of tubules. Absorption and Fresnel-propagated X-ray tomography are applied to measure samples of different rocks before and after mechanical compression nondestructively. In a first approach, limestone and greywacke are investigated, representing two sedimentary rocks of different grain size. Basalt and granite are tested in a second approach to compare different rock types. Development of cracks is observed in all materials, leading to fracture when increasing mechanical load is applied. In this work, relatively small mm-sized samples are used in order to test a classical fracture model wherein micro-flaws initiate the formation of larger cracks. For the first time, Fresnel-propagated imaging is applied to rock samples, highlighting micrometer-sized intergranular porosity as well as different material phases. The latter is

  3. X-ray imaging by partially coherent synchrotron light. Application to metallic alloys, tooth dentin and natural rock

    International Nuclear Information System (INIS)

    The hard spectrum which is available on the BAMline at Berlin's synchrotron BESSY offers the rare opportunity to perform high-resolution X-ray imaging experiments with a partially coherent beam. This thesis work reports on the development of a new tomography system, including Fresnel-propagated imaging, and its application to three specific materials science problems from the fields of engineering materials, biology and earth science. Static and dynamic 2D and 3D images were recorded from a variety of aluminum-based alloys. Coarsening of particle agglomerates (at high solid volume fraction) in liquid solution, as well as rheological properties of semi-solid alloys are thus characterized. Dentin is characterized by a quasi-parallel arrangement of micrometer-sized tubules. This work shows how high-resolution 3D images of water-immersed tooth dentin are recorded, and detailed simulations of the optical wave propagation reveal that Fresnel-images contain additional information about the dense cuff of peritubular dentin surrounding the tubules. The cuff thickness can be extrapolated from the interference fringes that form the propagated images of tubules. Absorption and Fresnel-propagated X-ray tomography are applied to measure samples of different rocks before and after mechanical compression nondestructively. In a first approach, limestone and greywacke are investigated, representing two sedimentary rocks of different grain size. Basalt and granite are tested in a second approach to compare different rock types. Development of cracks is observed in all materials, leading to fracture when increasing mechanical load is applied. In this work, relatively small mm-sized samples are used in order to test a classical fracture model wherein micro-flaws initiate the formation of larger cracks. For the first time, Fresnel-propagated imaging is applied to rock samples, highlighting micrometer-sized intergranular porosity as well as different material phases. The latter is shown

  4. Adenocarcinoma - chest x-ray (image)

    Science.gov (United States)

    This chest x-ray shows adenocarcinoma of the lung. There is a rounded light spot in the right upper lung (left side ... density. Diseases that may cause this type of x-ray result would be tuberculous or fungal granuloma, and ...

  5. In Depth Analyses of LEDs by a Combination of X-ray Computed Tomography (CT) and Light Microscopy (LM) Correlated with Scanning Electron Microscopy (SEM).

    Science.gov (United States)

    Meyer, Jörg; Thomas, Christian; Tappe, Frank; Ogbazghi, Tekie

    2016-01-01

    In failure analysis, device characterization and reverse engineering of light emitting diodes (LEDs), and similar electronic components of micro-characterization, plays an important role. Commonly, different techniques like X-ray computed tomography (CT), light microscopy (LM) and scanning electron microscopy (SEM) are used separately. Similarly, the results have to be treated for each technique independently. Here a comprehensive study is shown which demonstrates the potentials leveraged by linking CT, LM and SEM. In depth characterization is performed on a white emitting LED, which can be operated throughout all characterization steps. Major advantages are: planned preparation of defined cross sections, correlation of optical properties to structural and compositional information, as well as reliable identification of different functional regions. This results from the breadth of information available from identical regions of interest (ROIs): polarization contrast, bright and dark-field LM images, as well as optical images of the LED cross section in operation. This is supplemented by SEM imaging techniques and micro-analysis using energy dispersive X-ray spectroscopy. PMID:27341190

  6. Quark-Novae in post-accretion Low-Mass X-ray Binaries: A universal model for short-hard Gamma-Ray Bursts

    CERN Document Server

    Ouyed, Rachid; Jaikumar, Prashanth

    2010-01-01

    We show that several features reminiscent of short-hard GRBs arise naturally when Quark-Novae occur in post-accretion low-mass X-ray binaries with a circumbinary disk. Post-accretion conditions in a neutron star-white dwarf binary are just right for the conversion of the neutron star to a quark star (Quark-Nova). In our model, the subsequent interaction of material from the neutron star's ejected crust with the circumbinary disk explains the duration, variability and near-universal nature of the prompt emission in short-hard GRBs. We also describe a statistical approach to ejecta break-up and collision to obtain the photon spectrum in our model, which turns out remarkably similar to the empirical Band function (Band et al. 1993). We apply the model to the fluence and spectrum of GRB 000727, GRB 000218, and GRB980706A obtaining excellent fits. Extended emission (spectrum and duration) is explained by shock-heating and ablation of the white dwarf by the highly energetic ejecta. Depending on the orbital separati...

  7. The Dust Scattering Model Can Not Explain The Shallow X-ray Decay in GRB Afterglows

    CERN Document Server

    Shen, Rong-Feng; Kumar, Pawan; O'Brien, Paul T; Evans, Phil A

    2008-01-01

    A dust scattering model was recently proposed to explain the shallow X-ray decay (plateau) observed prevalently in Gamma-Ray Burst (GRB) early afterglows. In this model the plateau is the scattered prompt X-ray emission by the dust located close (about 10 to a few hundred pc) to the GRB site. In this paper we carefully investigate the model and find that the scattered emission undergoes strong spectral softening with time, due to the model's essential ingredient that harder X-ray photons have smaller scattering angle thus arrive earlier, while softer photons suffer larger angle scattering and arrive later. The model predicts a significant change, i.e., $\\Delta \\beta \\sim 2 - 3$, in the X-ray spectral index from the beginning of the plateau toward the end of the plateau, while the observed data shows close to zero softening during the plateau and the plateau-to-normal transition phase. The scattering model predicts a big difference between the harder X-ray light curve and the softer X-ray light curve, i.e., th...

  8. X-ray-powered macronovae

    CERN Document Server

    Kisaka, Shota; Nakar, Ehud

    2015-01-01

    A macronova (or kilonova) was observed as an infrared excess several days after short gamma-ray burst, GRB 130603B. Although the $r$-process radioactivity is widely discussed as an energy source, it requires huge mass of ejecta from a neutron star (NS) binary merger. We propose that the X-ray excess simultaneously observed with the infrared excess can naturally heat the ejecta, leading to the thermal re-emission as observed in infrared. This X-ray-powered model explains both the X-ray and infrared excesses with a single energy source by the central engine like a black hole, and allows for broader parameter region, in particular smaller ejecta mass $\\sim10^{-3}-10^{-2}M_{\\odot}$ with iron mixed as suggested by general relativistic simulations for typical NS-NS mergers, than the previous models. We also discuss the other macronova candidates in GRB 060614 and GRB 080503, and implications for the search of electromagnetic counterparts to gravitational waves.

  9. X-Ray-powered Macronovae

    Science.gov (United States)

    Kisaka, Shota; Ioka, Kunihito; Nakar, Ehud

    2016-02-01

    A macronova (or kilonova) was observed as an infrared excess several days after the short gamma-ray burst GRB 130603B. Although the r-process radioactivity is widely discussed as an energy source, it requires a huge mass of ejecta from a neutron star (NS) binary merger. We propose a new model in which the X-ray excess gives rise to the simultaneously observed infrared excess via thermal re-emission, and explore what constraints this would place on the mass and velocity of the ejecta. This X-ray-powered model explains both the X-ray and infrared excesses with a single energy source such as the central engine like a black hole, and allows for a broader parameter region than the previous models, in particular a smaller ejecta mass ˜ {10}-3{--}{10}-2{M}⊙ and higher iron abundance mixed as suggested by general relativistic simulations for typical NS-NS mergers. We also discuss the other macronova candidates in GRB 060614 and GRB 080503, and the implications for the search of electromagnetic counterparts to gravitational waves.

  10. X-ray interferometers

    International Nuclear Information System (INIS)

    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.)

  11. X-ray - skeleton

    Science.gov (United States)

    A skeletal x-ray is an imaging test used to look at the bones. It is used to detect fractures , tumors, or ... in the health care provider's office by an x-ray technologist. You will lie on a table or ...

  12. Extremity x-ray

    Science.gov (United States)

    An extremity x-ray is an image of the hands, wrist, feet, ankle, leg, thigh, forearm humerus or upper arm, hip, shoulder ... term "extremity" often refers to a human limb. X-rays are a form of radiation that passes through ...

  13. Dental x-rays

    Science.gov (United States)

    ... addition, many dentists are taking x-rays using digital technology. The image runs through a computer. The amount of radiation given off during the procedure is less than traditional methods. Other types of dental x-rays can create a 3-D picture ...

  14. Solution properties of a hydrophobically associating polyacrylamide and its polyelectrolyte derivatives determined by Light Scattering, Small Angle X-ray Scattering and viscometry

    International Nuclear Information System (INIS)

    A hydrophobically-modified polyacrylamide and two partially hydrolyzed derivatives containing hydrophobic and carboxylic groups were prepared by micellar polymerization and post hydrolysis. The molecular weight, second virial coefficient and radius of gyration were determined by static light scattering (SLS). Dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) were employed to determine the aggregate formation and type of chain packing in the semidilute regime, respectively. The behavior of solutions in dilute and semidilute regimes was also studied by viscometry and rheology. The hydrophobically-modified polyacrylamide showed a tendency to form aggregates due to the hydrophobic groups, but not enough to increase apparent viscosity. The partially hydrolyzed derivatives did not show the same aggregate-forming tendency. Rather, they exhibited anisotropic behavior, due to the charge density introduced into the polymer chain, which led to a more elongated macromolecular conformation and higher viscosity. (author)

  15. Solution properties of a hydrophobically associating polyacrylamide and its polyelectrolyte derivatives determined by Light Scattering, Small Angle X-ray Scattering and viscometry

    Energy Technology Data Exchange (ETDEWEB)

    Maia, Ana M.S.; Vidal, Rosangela R.L.; Balaban, Rosangela C., E-mail: balaban@supercabo.com.b [Universidade Federal do Rio Grande do Norte (LAPET/DQ/UFRN), Natal, RN (Brazil). Dept. de Quimica. Lab. de Pesquisa em Petroleo; Villetti, Marcos A. [Universidade Federal de Santa Maria (DF/UFSM), RS (Brazil). Dept. de Fisica; Borsali, Redouane [Universite Bordeaux 1, Pessac Cedex (France)

    2011-07-01

    A hydrophobically-modified polyacrylamide and two partially hydrolyzed derivatives containing hydrophobic and carboxylic groups were prepared by micellar polymerization and post hydrolysis. The molecular weight, second virial coefficient and radius of gyration were determined by static light scattering (SLS). Dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) were employed to determine the aggregate formation and type of chain packing in the semidilute regime, respectively. The behavior of solutions in dilute and semidilute regimes was also studied by viscometry and rheology. The hydrophobically-modified polyacrylamide showed a tendency to form aggregates due to the hydrophobic groups, but not enough to increase apparent viscosity. The partially hydrolyzed derivatives did not show the same aggregate-forming tendency. Rather, they exhibited anisotropic behavior, due to the charge density introduced into the polymer chain, which led to a more elongated macromolecular conformation and higher viscosity. (author)

  16. Discovery of the optical polarization flare following the X-ray giant outburst of V0332+53.

    Science.gov (United States)

    Slowikowska, Agnieszka; Reig, Pablo; Krzeszowski, Krzysztof; Zejmo, M. Michal

    2016-07-01

    V0332+53 is a transient Be X-ray binary that went through a giant outburst between June 2015 and October 2015 registered by the Gamma-ray Burst Monitor (GMB) on board of the Fermi satellite. We present the discovery of a flare of linearly polarized optical light in V0332+53 that followed the X-ray outburst. We monitored the source with the multi-wavelength optical polarimeter RINGO3 on the 2-m fully robotic Liverpool Telescope located at the Observatorio del Roque de Los Muchachos on La Palma. RINGO3 measures polarization simultaneously in three spectral wavelength bands: blue (350-640 nm), green (650-760 nm) and red (770-1000 nm). The polarized optical flare went off around 90 days after the X-ray burst and lasted another 90 days in all three wavelength bands of RINGO3. Polarization degree reached up to 6% in blue and up to 4% in red, while the PA changed by more than 100 degrees during the flare. This is the first detection of optical polarization flare of high mass X-ray binary correlated with a preceding X-ray outburst. Our observations shed new light on the activities of X-ray binaries.

  17. Microscopic x-ray luminescence computed tomography

    Science.gov (United States)

    Zhang, Wei; Zhu, Dianwen; Zhang, Kun; Li, Changqing

    2015-03-01

    X-ray luminescence computed tomography (XLCT) was emerged as a new hybrid imaging modality, in which the x-rays are used to excite phosphors emitting optical photons to be measured for imaging. In this paper, we reported a microscopic x-ray luminescence computed tomography (microXLCT) with a spatial resolution up to hundreds of micrometers for deep targets. We use a superfine x-ray pencil beam to scan the phosphor targets. The superfine x-ray pencil beam is generated by a small collimator mounted in front of a powerful x-ray tube (93212, Oxford Instrument). A CT detector is used to image the x-ray beam. We have generated an x-ray beam with a diameter of 192 micrometers with a collimator of 100 micrometers in diameter. The emitted optical photons on the top surface of phantom are reflected by a mirror and acquired by an electron multiplier charge-coupled device (EMCCD) camera (C9100-13, Hamamatsu Photonics). The microXLCT imaging system is built inside an x-ray shielding and light tight cabinet. The EMCCD camera is placed in a lead box. All the imaging components are controlled by a VC++ program. The optical photon propagation is modeled with the diffusion equation solved by the finite element method. We have applied different regularization methods including L2 and L1 in the microXLCT reconstruction algorithms. Numerical simulations and phantom experiments are used to validate the microXLCT imaging system.

  18. High Energy Vision: Processing X-rays

    CERN Document Server

    DePasquale, Joseph; Edmonds, Peter

    2015-01-01

    Astronomy is by nature a visual science. The high quality imagery produced by the world's observatories can be a key to effectively engaging with the public and helping to inspire the next generation of scientists. Creating compelling astronomical imagery can, however, be particularly challenging in the non-optical wavelength regimes. In the case of X-ray astronomy, where the amount of light available to create an image is severely limited, it is necessary to employ sophisticated image processing algorithms to translate light beyond human vision into imagery that is aesthetically pleasing while still being scientifically accurate. This paper provides a brief overview of the history of X-ray astronomy leading to the deployment of NASA's Chandra X-ray Observatory, followed by an examination of the specific challenges posed by processing X-ray imagery. The authors then explore image processing techniques used to mitigate such processing challenges in order to create effective public imagery for X-ray astronomy. ...

  19. How long does a burst burst?

    International Nuclear Information System (INIS)

    Several gamma-ray bursts (GRBs) last much longer (∼hours) in γ-rays than typical long GRBs (∼minutes), and it has recently been proposed that these 'ultra-long GRBs' may form a distinct population, probably with a different (e.g., blue supergiant) progenitor than typical GRBs. However, Swift observations suggest that many GRBs have extended central engine activities manifested as flares and internal plateaus in X-rays. We perform a comprehensive study on a large sample of Swift GRBs with X-Ray Telescope observations to investigate GRB central engine activity duration and to determine whether ultra-long GRBs are unusual events. We define burst duration t burst based on both γ-ray and X-ray light curves rather than using γ-ray observations alone. We find that t burst can be reliably measured in 343 GRBs. Within this 'good' sample, 21.9% GRBs have t burst ≳ 103 s and 11.5% GRBs have t burst ≳ 104 s. There is an apparent bimodal distribution of t burst in this sample. However, when we consider an 'undetermined' sample (304 GRBs) with t burst possibly falling in the gap between GRB duration T 90 and the first X-ray observational time, as well as a selection effect against t burst falling into the first Swift orbital 'dead zone' due to observation constraints, the intrinsic underlying t burst distribution is consistent with being a single component distribution. We found that the existing evidence for a separate ultra-long GRB population is inconclusive, and further multi-wavelength observations are needed to draw a firmer conclusion. We also discuss the theoretical implications of our results. In particular, the central engine activity duration of GRBs is generally much longer than the γ-ray T 90 duration and it does not even correlate with T 90. It would be premature to make a direct connection between T 90 and the size of the progenitor star.

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

    Indian Academy of Sciences (India)

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

    2014-07-01

    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.

  1. Investigation of magnetically smart films applied to correct the surface profile of light weight X-ray optics in two directions

    Science.gov (United States)

    Wang, Xiaoli; Yao, Youwei; Cao, Jian; Vaynman, Semyon; Graham, Michael E.; Liu, Tianchen; Ulmer, M. P.

    2015-09-01

    Our goal is to improve initially fabricated X-ray optics figures by applying a magnetic field to drive a magnetic smart material (MSM) coating on the non-reflecting side of the mirror. The consequent deformation of the surface should be three-dimensional. Here we will report on the results of working with a glass sample of 50x50x0.2 mm that has been coated with MSMs. The coated glass can be deformed in 3 dimensions and its surface profile was measured under our Zygo NewView white light interferometer (WLI). The driving magnetic field was produced via a pseudo-magnetic write head made up of two permanent magnet posts. The magnet posts were moved about the bottom of the glass sample with a 3-d computer controlled translation stage. The system allowed four degrees of freedom of motion, i.e., up and down, side to side, back and forth, and rotation of the posts (3.175 mm diameter) about the vertical axis to allow us to change the orientation of the magnetic field in the (horizontal) plane of the sample. We established a finite element analysis (FEA) model to predict deformations and compare with the observed results in order to guide the application of the magnetically controlled MSMs to improve the future X-ray optics figures.

  2. Crystallization and vitrification of a PdCuNiP metallic glass upon thermal and mechanical processes detected by synchrotron light X-ray radiation

    Science.gov (United States)

    Georgarakis, K.; Yavari, A. R.; Louzguine-Luzgin, D. V.; Vaughan, G.

    2013-02-01

    In-situ vitrification and crystallization of a PdCuNiP metallic glass was investigated using synchrotron light X-ray diffraction. Distinct differences between the Bragg peaks appearing upon thermal annealing of the glassy phase and those appearing during solidification from the melt were detected. This observation indicates that the crystal phases which are in competition with the amorphous phase during rapid quenching are not always the same with those precipitating upon annealing, contrary to a general believe. Measurements during in-situ vitrification allowed the determination of structural changes in the supercooled liquid and glassy states using real-space atomic pair PDF(r) and radial RDF(r) distribution functions. The first PDF peak corresponding to the first nearest neighbor (nn) coordination shell has a pre-peak at low interatomic distance (r) which grows during cooling from the liquidus temperature to the glass transition in the supercooled liquid region. A reversible expansion of the nn distances in the first coordination shell is observed in the same temperature range. Crystallization of shear bands operating under compressive applied stress previously observed by transmission electron microscopy has been non-destructively detected by synchrotron X-ray microscopy in transmission. Analysis of crystal nucleation frequencies under hydrostatic pressure shows that crystal nucleation is more favorable under compression loading.

  3. 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.

  4. Light speed variation from gamma-ray bursts

    CERN Document Server

    Xu, Haowei

    2016-01-01

    The effect of quantum gravity can bring a tiny light speed variation which is detectable through energetic photons propagating from gamma ray bursts (GRBs) to an observer such as the space observatory. Through an analysis of the energetic photon data of the GRBs observed by the Fermi Gamma-ray Space Telescope (FGST), we reveal a surprising regularity of the observed time lags between photons of different energies with respect to the Lorentz violation factor due to the light speed energy dependence. Such regularity suggests a linear form correction of the light speed $v(E)=c(1-E/E_{\\rm LV})$, where $E$ is the photon energy and $E_{\\rm LV}=(3.60 \\pm 0.26) \\times 10^{17}~ \\rm GeV$ is the Lorentz violation scale measured by the energetic photon data of GRBs. The results support an energy dependence of the light speed in cosmological space.

  5. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  6. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  7. Bone X-Ray (Radiography)

    Medline Plus

    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 ...

  8. Lumbosacral spine x-ray

    Science.gov (United States)

    X-ray - lumbosacral spine; X-ray - lower spine ... The test is done in a hospital x-ray department or your health care provider's office by an x-ray technician. You will be asked to lie on the x-ray table ...

  9. 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 ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

  10. 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 ... of an abdominal x-ray? What is abdominal x-ray? An x-ray (radiograph) is a noninvasive medical ...

  11. 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.

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

    International Nuclear Information System (INIS)

    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

  13. X-ray apparatus

    International Nuclear Information System (INIS)

    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.)

  14. 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

  15. Tuberculosis, advanced - chest x-rays (image)

    Science.gov (United States)

    Tuberculosis is an infectious disease that causes inflammation, the formation of tubercules and other growths within tissue, ... death. These chest x-rays show advanced pulmonary tuberculosis. There are multiple light areas (opacities) of varying ...

  16. Effects of Pamidronate on Dental Enamel Formation Assessed by Light Microscopy, Energy-Dispersive X-Ray Analysis, Scanning Electron Microscopy, and Microhardness Testing.

    Science.gov (United States)

    Soares, Ana P; do Espírito Santo, Renan F; Line, Sérgio R P; Pinto, Maria das G F; Santos, Pablo de M; Toralles, Maria Betania P; do Espírito Santo, Alexandre R

    2016-06-01

    The aim of the present work was to investigate birefringence and morphology of the secretory-stage enamel organic extracellular matrix (EOECM), and structural and mechanical properties of mature enamel of upper incisors from adult rats that had been treated with pamidronate disodium (0.5 mg/kg/week for 56 days), using transmitted polarizing and bright-field light microscopies (TPLM and BFLM), energy-dispersive X-ray (EDX) analysis, scanning electron microscopy (SEM) and microhardness testing. BFLM showed no morphological changes of the EOECM in pamidronate and control groups, but TPLM revealed a statistically significant reduction in optical retardation values of birefringence brightness of pamidronate-treated rats when compared with control animals (p0.05). The present study indicates that pamidronate can affect birefringence of the secretory-stage EOECM, which does not seem to be associated with significant changes in morphological and/or mechanical properties of mature enamel. PMID:27212049

  17. Thallium magnesium chloride: A high light yield, large effective atomic number, intrinsically activated crystalline scintillator for X-ray and gamma-ray detection

    Science.gov (United States)

    Fujimoto, Yutaka; Koshimizu, Masanori; Yanagida, Takayuki; Okada, Go; Saeki, Keiichiro; Asai, Keisuke

    2016-09-01

    We report the luminescence and the scintillation properties of a newly developed thallium magnesium chloride (TlMgCl3) crystal. The crystal sample can be easily fabricated from the melt using the Bridgman method. The photoluminescence band appeared near the wavelength of 405 nm under excitation at 230 nm. An X-ray-induced scintillation spectrum showed an intense emission band near the wavelength of 405 nm. The decay time constant was estimated to be approximately 60 ns (∼25%) and 350 ns (∼75%) using a bi-exponential fitting. The scintillation light yield reached 46,000 photons/MeV with an energy resolution of 5% at 662 keV.

  18. Structural studies of polymers and polymer liquid crystals by X-ray scattering, thermal analysis and ellipsometric studies through polarized light microscopy

    Science.gov (United States)

    Georgiev, Georgi Yordanov

    We have studied the phase transformation behavior and structure of binary polymer blends and polymer liquid crystalline materials, to understand the formation of long and short-range ordered structures. We investigated their crystallization, melting and liquid crystalline behavior using Small Angle X-ray Scattering (SAXS), Wide Angle X-ray Scattering (WAXS), Modulated Differential Scanning Calorimetry (MDSC), Polarized Light Microcopy (PLM), and Scanning Probe Microscopy (SPM). Materials selected for the study were: (1) a miscible blend of semicrystalline poly(etheretherketone), PEEK, and noncrystallizable poly(etherimide), PEI; (2) an immiscible blend of poly(ethyleneterephtalate), PET, and liquid crystalline polymer, Vectra RTM; (3) a thermotropic liquid crystalline random copolyester HIQ-40; and (4) new biological collagen model peptides. We explore the phenomenon of multiple melting endotherms seen through MDSC after thermal pre-treatment of PEEK/PEI blend at different crystallization temperatures. Multiple melting endotherms have several possible origins, including melting of several populations of crystals with different lamellar thicknesses, melting of different crystallographic forms, or melting and recrystallization of the same population of crystals. The location of the amorphous phase, whether it is interlamellar, interfibrillar or interspherulite is addressed, by comparing the total crystallinity of the sample obtained by DSC and the linear stack crystallinity obtained by SAXS. Also by the temperature dependence of the smaller thickness determined from the SAXS correlation function, we were able to assign it to the crystalline thickness of the lamellae. We studied the effect of Vectra on the crystallization behavior of PET, and found that it slows the nucleation time for crystallization, and decreases the sample viscosity. By X-ray scattering and Differential Scanning Calorimetry and optical measurements we showed that the liquid crystalline component

  19. X-Ray Diffraction.

    Science.gov (United States)

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  20. Medical X-Rays

    Science.gov (United States)

    ... The Conference of Radiation Control Program Directors (CRCPD) publishes Suggested State Regulations for the Control of Radiation , ... eSubmitter Guidance for Industry and Food and Drug Administration Staff - Assembler's Guide to Diagnostic X-Ray Equipment ...