WorldWideScience

Sample records for balloon-borne hard x-ray

  1. A 3D CZT hard x-ray polarimeter for a balloon-borne payload

    DEFF Research Database (Denmark)

    Caroli, E.; Alvarez, J. M.; Auricchio, N.;

    2012-01-01

    be optimized also for this type of measurement. In this framework, we present the concept of a small high-performance spectrometer designed for polarimetry between 100 and 1000 keV suitable as a stratospheric balloon-borne payload dedicated to perform an accurate and reliable measurement of the polarization...... development results and possible improvements currently under study. Furthermore we describe a possible baseline design of the payload, which can be also seen as a pathfinder for a high performance focal plane detector in new hard X and soft gamma ray focussing telescopes and/or advanced Compton instruments...

  2. The design and flight performance of the PoGOLite Pathfinder balloon-borne hard X-ray polarimeter

    CERN Document Server

    Chauvin, M; Jackson, M; Kamae, T; Kawano, T; Kiss, M; Kole, M; Mikhalev, V; Moretti, E; Olofsson, G; Rydström, S; Takahashi, H; Lind, J; Strömberg, J -E; Welin, O; Iyudin, A; Shifrin, D; Pearce, M

    2015-01-01

    In the 50 years since the advent of X-ray astronomy there have been many scientific advances due to the development of new experimental techniques for detecting and characterising X-rays. Observations of X-ray polarisation have, however, not undergone a similar development. This is a shortcoming since a plethora of open questions related to the nature of X-ray sources could be resolved through measurements of the linear polarisation of emitted X-rays. The PoGOLite Pathfinder is a balloon-borne hard X-ray polarimeter operating in the 25 - 240 keV energy band from a stabilised observation platform. Polarisation is determined using coincident energy deposits in a segmented array of plastic scintillators surrounded by a BGO anticoincidence system and a polyethylene neutron shield. The PoGOLite Pathfinder was launched from the SSC Esrange Space Centre in July 2013. A near-circumpolar flight was achieved with a duration of approximately two weeks. The flight performance of the Pathfinder design is discussed for the...

  3. Balloon-borne hard X-ray polarimetry with PoGOLite

    CERN Document Server

    ,

    2012-01-01

    PoGOLite is a hard X-ray polarimeter operating in the 25-100 keV energy band. The instrument design is optimised for the observation of compact astrophysical sources. Observations are conducted from a stabilised stratospheric balloon platform at an altitude of approximately 40 km. The primary targets for first balloon flights of a reduced effective area instrument are the Crab and Cygnus-X1. The polarisation of incoming photons is determined using coincident Compton scattering and photo-absorption events reconstructed in an array of plastic scintillator detector cells surrounded by a bismuth germanate oxide (BGO) side anticoincidence shield and a polyethylene neutron shield. A custom attitude control system keeps the polarimeter field-of-view aligned to targets of interest, compensating for sidereal motion and perturbations such as torsional forces in the balloon rigging. An overview of the PoGOLite project is presented and the outcome of the ill-fated maiden balloon flight is discussed.

  4. Optimising a balloon-borne polarimeter in the hard X-ray domain: From the PoGOLite Pathfinder to PoGO+

    Science.gov (United States)

    Chauvin, M.; Jackson, M.; Kawano, T.; Kiss, M.; Kole, M.; Mikhalev, V.; Moretti, E.; Takahashi, H.; Pearce, M.

    2016-09-01

    PoGOLite is a balloon-borne hard X-ray polarimeter dedicated to the study of point sources. Compton scattered events are registered using an array of plastic scintillator units to determine the polarisation of incident X-rays in the energy range 20-240 keV. In 2013, a near circumpolar balloon flight of 14 days duration was completed after launch from Esrange, Sweden, resulting in a measurement of the linear polarisation of the Crab emission. Building on the experience gained from this Pathfinder flight, the polarimeter is being modified to improve performance for a second flight in 2016. Such optimisations, based on Geant4 Monte Carlo simulations, take into account the source characteristics, the instrument response and the background environment which is dominated by atmospheric neutrons. This paper describes the optimisation of the polarimeter and details the associated increase in performance. The resulting design, PoGO+, is expected to improve the Minimum Detectable Polarisation (MDP) for the Crab from 19.8% to 11.1% for a 5 day flight. Assuming the same Crab polarisation fraction as measured during the 2013 flight, this improvement in MDP will allow a 5σ constrained result. It will also allow the study of the nebula emission only (Crab off-pulse) and Cygnus X-1 if in the hard state.

  5. Optimising a balloon-borne polarimeter in the hard X-ray domain: from the PoGOLite Pathfinder to PoGO+

    CERN Document Server

    Chauvin, Maxime; Kawano, Takafumi; Kiss, Mózsi; Kole, Merlin; Mikhalev, Victor; Moretti, Elena; Takahashi, Hiromitsu; Pearce, Mark

    2016-01-01

    PoGOLite is a balloon-borne hard X-ray polarimeter dedicated to the study of point sources. Compton scattered events are registered using an array of plastic scintillator units to determine the polarisation of incident X-rays in the energy range 20 - 240 keV. In 2013, a near circumpolar balloon flight of 14 days duration was completed after launch from Esrange, Sweden, resulting in a measurement of the linear polarisation of the Crab emission. Building on the experience gained from this Pathfinder flight, the polarimeter is being modified to improve performance for a second flight in 2016. Such optimisations, based on Geant4 Monte Carlo simulations, take into account the source characteristics, the instrument response and the background environment which is dominated by atmospheric neutrons. This paper describes the optimisation of the polarimeter and details the associated increase in performance. The resulting design, PoGO+, is expected to improve the Minimum Detectable Polarisation (MDP) for the Crab from ...

  6. Status of the Balloon-Borne X-ray Polarimetry Mission X-Calibur

    Science.gov (United States)

    Krawczynski, Henric; Kislat, Fabian; Stuchlik, David; Okajima, Takashi; de Geronimo, Gianluigi

    2016-04-01

    We report on the status of the balloon borne hard X-ray polairmetry mission X-Calibur. The missions combines a focussing hard X-ray mirror from the InFOCuS collaboration with a scattering polarimeter and the WASP (Wallops Arc Second Pointer) pointing system. The mission is scheduled for a conventonal ~1 day balloon flight in Fall 2016 and a long duration (~30 day) balloon flight from McMurdo (Ross Island) in 2018/2019. X-Calibur will allow us to measure ~5% polarization fractions for strong sources with a Crab-like enegry spectra and fluxes. The science targets of the first balloon flights will include the stellar mass black holes GRS 1915+105 and Cyg X-1, Her X-1, Sco X-1, and the Crab nebula and pulsar. The long duration balloon flight will target several X-ray binaries and the extragalactic mass accreting supermassive black hole Cen A. In this contribution we give an update on the status of the mission, and the expected science return.

  7. Study of the properties of Cosmic rays and solar X-Ray Flares by balloon borne experiments

    CERN Document Server

    Chakrabarti, S K; Chakraborty, S; Palit, S; Mondal, S K; Bhattacharya, A; Midya, S; Chakrabarti, S

    2013-01-01

    Indian Centre for Space Physics is engaged in pioneering balloon borne experiments with typical payloads less than ~ 3.5kg. Low cost rubber balloons are used to fly them to a height of about 40km. In a double balloon system, the booster balloon lifts the orbiter balloon to its cruising altitude where data is taken for a longer period of time. In this Paper, we present our first scientific report on the variation of Cosmic Rays and muons with altitude and detection of several solar flares in X-rays between 20keV and 100keV. We found the altitude of the Pfotzer maximum at Tropic of Cancer for cosmic rays and muons and catch several solar flares in hard X-rays. We find that the hard X-ray (> 40keV) sky becomes very transparent above Pfotzer maximum. We find the flare spectrum to have a power-law distribution. From these studies, we infer that valuable scientific research could be carried out in near space using low cost balloon borne experiments. Published in Online version of Indian Journal of Physics.

  8. First Images from HERO: A Hard-X-Ray Focusing Telescope

    Science.gov (United States)

    Ramsey, Brian D.; Alexander, Cheryl D.; Apple, Jeff A.; Benson, Carl M.; Dietz, Kurtis L.; Elsner, Ronald F.; Engelhaupt, Darell E.; Ghosh, Kajal K.; Kolodziejczak, Jeffery J.; ODell, Stephen L.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    We are developing a balloon-borne hard-x-ray telescope that utilizes grazing incidence optics. Termed HERO, for High-Energy Replicated Optics, the instrument will provide unprecented sensitivity in the hard-x-ray region and will achieve milliCrab-level sensitivity in a typical 3-hour balloon-flight observation and 50 microCrab sensitivity on ultra-long-duration flights. A recent proof-of-concept flight, featuring a small number of mirror shells captured the first focused hard-x-ray images of galactic x-ray sources. Full details of the payload, its expected future performance and its recent measurements are provided.

  9. Hard X-ray Modulation Telescope

    Institute of Scientific and Technical Information of China (English)

    LU Fangjun

    2011-01-01

    The Hard X-ray Modulation Telescope (HXMT) will be China's first astronomical satellite. On board HXMT there are three kinds of slat-collimated telescopes, the High Energy X-ray Telescope (HE, 20-250 keV, 5000 cm^2), the Medium Energy X-ray Telescope (ME, 5-30 keV, 952 cm^2), and the Low Energy X-ray Telescope (LE, 1-15 keV, 384 cm^2).

  10. Microfabrication of hard x-ray lenses

    DEFF Research Database (Denmark)

    Stöhr, Frederik

    in the vertical and horizontal directions was addressed. A functioning prototype of a 2D silicon objective for use in a bright-field hard-XRM was demonstrated. The results are promising; showing acceptably low aberration and performance close to theoretical expectations. A resolution of 300 nm with 17 keV x...... rate larger than 10 pieces per hour indicates the economic value of injection molded x-ray lenses, which may have applications in more readily available small laboratory x-ray instruments or medical devices. In each case, observed non-uniformities of the shaped x-ray beams were investigated and found...

  11. Systematic and Performance Tests of the Hard X-ray Polarimeter X-Calibur

    Science.gov (United States)

    Endsley, Ryan; Beilicke, Matthias; Kislat, Fabian; Krawczynski, Henric; X-Calibur/InFOCuS

    2015-01-01

    X-ray polarimetry has great potential to reveal new astrophysical information about the emission processes of high energy sources such as black hole environments, X-ray binary systems, and active galactic nuclei. Here we present the results and conclusions of systematic and performance measurements of the hard X-ray polarimeter, X-Calibur. Designed to be flown on a balloon-borne X-ray telescope, X-Calibur will achieve unprecedented sensitivity and makes use of the fact that polarized X-rays preferentially Compton-scatter perpendicular to their E-field vector. Extensive laboratory measurements taken at Washington University and the Cornell High-Energy Synchrotron Source (CHESS) indicate that X-Calibur combines a detection efficiency on the order of unity with a high modulation factor of µ ≈ 0.5 averaged over the whole detector assembly, and with values up to µ ≈ 0.7 for select subsections of the polarimeter. Additionally, we are able to suppress background flux by more than two orders of magnitude by utilizing an active shield and scintillator coincidence. Comparing laboratory data with Monte Carlo simulations of both polarized and unpolarized hard X-ray beams illustrate that we have an exceptional understanding of the detector response.

  12. Blazar microvariability at hard X-rays

    OpenAIRE

    Foschini, L.; Gliozzi, M.; Pian, E.; Tagliaferri, G.; Tavecchio, F.; Bianchin, V.; L. Maraschi(INAF National Institute for Astrophysics, I-00136 Rome, Italy); Sambruna, R. M.; Di Cocco, G.; Ghisellini, G.; Malaguti, G.; Tosti, G.; Treves, A.

    2007-01-01

    Blazars are known to display strong and erratic variability at almost all the wavelengths of electromagnetic spectrum. Presently, variability studies at high-energies (hard X-rays, gamma-rays) are hampered by low sensitivity of the instruments. Nevertheless, the latest generation of satellites (INTEGRAL, Swift) have given suggestions not yet fully confirmed of variability on intraday timescales. Some specific cases recently observed are presented and physical implications are discussed (e.g. ...

  13. AGN variability at hard X-rays

    CERN Document Server

    Soldi, S; Beckmann, V; Lubinski, P

    2010-01-01

    We present preliminary results on the variability properties of AGN above 20 keV in order to show the potential of the INTEGRAL IBIS/ISGRI and Swift/BAT instruments for hard X-ray timing analysis of AGN. The 15-50 keV light curves of 36 AGN observed by BAT during 5 years show significantly larger variations when the blazar population is considered (average normalized excess variance = 0.25) with respect to the Seyfert one (average normalized excess variance = 0.09). The hard X-ray luminosity is found to be anti-correlated to the variability amplitude in Seyfert galaxies and correlated to the black hole mass, confirming previous findings obtained with different AGN hard X-ray samples. We also present results on the Seyfert 1 galaxy IC 4329A, as an example of spectral variability study with INTEGRAL/ISGRI data. The position of the high-energy cut-off of this source is found to have varied during the INTEGRAL observations, pointing to a change of temperature of the Comptonising medium. For several bright Seyfert...

  14. The protoMIRAX Hard X-ray Imaging Balloon Experiment

    CERN Document Server

    Braga, João; Avila, Manuel A C; Penacchioni, Ana V; Sacahui, J Rodrigo; Santiago, Valdivino A de; Mattiello-Francisco, Fátima; Strauss, Cesar; Fialho, Márcio A A

    2015-01-01

    The protoMIRAX hard X-ray imaging telescope is a balloon-borne experiment developed as a pathfinder for the MIRAX satellite mission. The experiment consists essentially in a coded-aperture hard X-ray (30-200 keV) imager with a square array (13$\\times$13) of 2mm-thick planar CZT detectors with a total area of 169 cm$^2$. The total, fully-coded field-of-view is $21^{\\circ}\\times 21^{\\circ}$ and the angular resolution is 1$^{\\circ}$43'. In this paper we describe the protoMIRAX instrument and all the subsystems of its balloon gondola, and we show simulated results of the instrument performance. The main objective of protoMIRAX is to carry out imaging spectroscopy of selected bright sources to demonstrate the performance of a prototype of the MIRAX hard X-ray imager. Detailed background and imaging simulations have been performed for protoMIRAX balloon flights. The 3$\\sigma$ sensitivity for the 30-200 keV range is ~1.9 $\\times$ 10$^{-5}$ photons cm$^{-2}$ s$^{-1}$ for an integration time of 8 hs at an atmospheric ...

  15. Hard x-ray telescope mission

    DEFF Research Database (Denmark)

    Gorenstein, P.; Worrall, D.; Joensen, K.D.;

    1996-01-01

    The Hard X-Ray Telescope was selected for study as a possible new intermediate size mission for the early 21st century. Its principal attributes are: (1) multiwavelength observing with a system of focussing telescopes that collectively observe from the UV to over 1 MeV, (2) much higher sensitivity...... and much better angular resolution in the 10 - 100 keV band, and (3) higher sensitivity for detecting gamma ray lines of known energy in the 100 keV to 1 MeV band. This paper emphasizes the mission aspects of the concept study such as the payload configuration and launch vehicle. An engineering team...

  16. Preflight performance studies of the PoGOLite hard X-ray polarimeter

    CERN Document Server

    Chauvin, M; Kawano, T; Kiss, M; Kole, M; Mikhalev, V; Moretti, E; Takahashi, H; Pearce, M

    2015-01-01

    Polarimetric studies of astrophysical sources can make important contributions to resolve the geometry of the emitting region and determine the photon emission mechanism. PoGOLite is a balloon-borne polarimeter operating in the hard X-ray band (25-240 keV), with a Pathfinder mission focussing on Crab observations. Within the polarimeter, the distribution of Compton scattering angles is used to determine the polarisation fraction and angle of incident photons. To assure an unbiased measurement of the polarisation during a balloon flight it is crucial to characterise the performance of the instrument before the launch. This paper presents the results of the PoGOLite calibration tests and simulations performed before the 2013 balloon flight. The tests performed confirm that the polarimeter does not have any intrinsic asymmetries and therefore does not induce bias into the measurements. Generally, good agreement is found between results from test data and simulations which allows the polarimeter performance to be...

  17. Soft X-Ray Spectra of AGN Discovered Via Their Hard X-Ray

    Science.gov (United States)

    Schwartz, Daniel

    1998-01-01

    This final report is a study of the Active Galactic Nuclei (AGN). Investigation of the soft x-ray spectra of AGN were performed by using their hard x-ray emission. ROSAT observations of AGN was also performed, which allowed for the study of these x-ray spectra and the structures of 7 clusters of galaxies.

  18. Broad-band hard X-ray reflectors

    DEFF Research Database (Denmark)

    Joensen, K.D.; Gorenstein, P.; Hoghoj, P.;

    1997-01-01

    Interest in optics for hard X-ray broad-band application is growing. In this paper, we compare the hard X-ray (20-100 keV) reflectivity obtained with an energy-dispersive reflectometer, of a standard commercial gold thin-film with that of a 600 bilayer W/Si X-ray supermirror. The reflectivity of ...

  19. Electron spectra deduced from solar hard X-ray bursts

    Energy Technology Data Exchange (ETDEWEB)

    Trottet, G.; Vilmer, N.

    1984-01-01

    Information regarding the acceleration of electrons in solar flares may be deduced from the hard X-ray emission they produce through bremsstrahlung. From these observations, the electron energy spectra and temporal evolution as well as some characteristics of the ambient medium can be deduced through models. Here, a model of hard X-ray emission is briefly presented and some of the results are discussed in the light of hard X-ray observations and acceleration processes. 18 references.

  20. Prospects for supermirrors in hard x-ray spectroscopy

    DEFF Research Database (Denmark)

    Joensen, Karsten D.; Gorenstein, Paul; Christensen, Finn Erland;

    1994-01-01

    reflectivity for x rays. For hard x rays (≥ 15 keV), the absorption, however, is low enough that it is possible to design supermirrors with 10 - 70% reflectivity in a band ≈ 3 times the width of the total reflection regime. Supermirrors of W/Si and Ni/C have been successfully fabricated and characterized....... The measured x-ray reflectivities are well accounted for by the standard dynamical theories of multilayer reflection. Hard x ray applications that could benefit from x-ray supermirror coatings include focusing and imaging instrumentation for astrophysics, collimating and focusing devices for synchrotron...

  1. Observation of polarised hard X-ray emission from the Crab by the PoGOLite Pathfinder

    CERN Document Server

    Chauvin, M; Jackson, M; Kamae, T; Kawano, T; Kiss, M; Kole, M; Mikhalev, V; Moretti, E; Olofsson, G; Rydström, S; Takahashi, H; Iyudin, A; Arimoto, M; Fukazawa, Y; Kataoka, J; Kawai, N; Mizuno, T; Ryde, F; Tajima, H; Takahashi, T; Pearce, M

    2015-01-01

    We have measured the linear polarisation of hard X-ray emission from the Crab in a previously unexplored energy interval, 20-120 keV. The introduction of two new observational parameters, the polarisation fraction and angle stands to disentangle geometrical and physical effects, thereby providing information on the pulsar wind geometry and magnetic field environment. Measurements are conducted using the PoGOLite Pathfinder - a balloon-borne polarimeter. Polarisation is determined by measuring the azimuthal Compton scattering angle of incident X-rays in an array of plastic scintillators housed in an anticoincidence well. The polarimetric response has been characterised prior to flight using both polarised and unpolarised calibration sources. We address possible systematic effects through observations of a background field. The measured polarisation fraction for the integrated Crab light-curve is ($18.4^{+9.8}_{-10.6}$)%, corresponding to an upper limit (99% credibility) of 42.4%, for a polarisation angle of ($...

  2. The smallest hard X-ray flare?

    Science.gov (United States)

    Glesener, Lindsay; Krucker, Sam; Hannah, Iain; Smith, David M.; Grefenstette, Brian; Marsh, Andrew; Hudson, Hugh S.; White, Stephen M.; Chen, Bin

    2016-05-01

    We report a NuSTAR observation of a small solar flare on 2015 September 1, estimated to be on the order of a GOES class A.05 flare in brightness. This flare is fainter than any hard X-ray (HXR) flares in the existing literature, and with a peak rate of only ∼5 counts s‑1 detector‑1 observed by RHESSI, is effectively the smallest that can just barely be detected by the current standard (indirectly imaging) solar HXR instrumentation, though we expect that smaller flares will continue to be discovered as instrumental and observational techniques progress. The flare occurred during a solar observation by the highly sensitive NuSTAR astrophysical HXR spacecraft, which used its direct focusing optics to produce detailed flare spectra and images. The flare exhibits properties commonly observed in larger flares, including a fast rise and more gradual decay, and similar spatial dimensions to the RHESSI microflares. We will discuss the presence of non-thermal (flare-accelerated) electrons during the impulsive phase. The flare is small in emission measure, temperature, and energy, though not in physical dimensions. Its presence is an indication that flares do indeed scale down to smaller energies and retain what we customarily think of as “flarelike” properties.

  3. Hard X-ray Variability of AGN

    CERN Document Server

    Beckmann, V; Courvoisier, T J -L; Gehrels, N; Soldi, S; Tüller, J; Wendt, G

    2007-01-01

    Aims: Active Galactic Nuclei are known to be variable throughout the electromagnetic spectrum. An energy domain poorly studied in this respect is the hard X-ray range above 20 keV. Methods: The first 9 months of the Swift/BAT all-sky survey are used to study the 14 - 195 keV variability of the 44 brightest AGN. The sources have been selected due to their detection significance of >10 sigma. We tested the variability using a maximum likelihood estimator and by analysing the structure function. Results: Probing different time scales, it appears that the absorbed AGN are more variable than the unabsorbed ones. The same applies for the comparison of Seyfert 2 and Seyfert 1 objects. As expected the blazars show stronger variability. 15% of the non-blazar AGN show variability of >20% compared to the average flux on time scales of 20 days, and 30% show at least 10% flux variation. All the non-blazar AGN which show strong variability are low-luminosity objects with L(14-195 keV) < 1E44 erg/sec. Conclusions: Concer...

  4. Backscatter, anisotropy, and polarization of solar hard X-rays

    Science.gov (United States)

    Bai, T.; Ramaty, R.

    1978-01-01

    The problems of anisotropy, polarization, center-to-limb variation of the X-ray spectrum, and Compton backscatter are investigated in a study of solar hard X-rays. Effect of backscatter are found particularly important for anisotropic sources which emit hard X-rays predominantly toward the photosphere; for such anisotropic primary X-ray sources, the observed X-ray flux near 30 keV does not depend significantly on the position of the flare. In addition, the degree of polarization of the sum of the primary and reflected X-rays with energies in the 15 to 30 keV range may be as high as 30%. Determination of the height and anisotropy of the primary X-ray sources from study of the albedo patch is also discussed.

  5. Hard X-ray micro-focusing beamline at SSRF

    Institute of Scientific and Technical Information of China (English)

    张丽丽; 兰旭颖; 毛成文; 王娟; 蒋晖; 郑怡; 董朝晖; 曾乐勇; 李爱国; 闫帅; 蒋升; 杨科; 王华; 何上明; 梁东旭; 张玲; 何燕

    2015-01-01

    The hard X-ray micro-focusing beamline (BL15U1) of SSRF is dedicated to hard X-ray micro/nano-spectrochemical analysis consisting of X-ray fluorescence (XRF), X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) techniques. It is one of the most versatile instruments in hard X-ray microscopy sci-ence. Since its commission in 2009, BL15U1 has allocated over 25000 h beamtime for users, and about 700 proposals have been executed. The beamline and the experimental end-station were upgraded for several times to facilitate the users’ experimental needs and make it more convenient to operate. In this paper, we give a review on the beamline, describing its characteristics, recent technical developments, and a few examples of scientific progresses achieved in recent years on BL15U1.

  6. Hard X-Ray, Soft X-Ray, and EUV Studies of Solar Eruptions

    Science.gov (United States)

    Sterling, Alphonse C.; Wagner, William (Technical Monitor)

    2003-01-01

    Document study the hard X-ray (HXR), soft X-ray (SXR) ,EUV, and magnetic nature of solar eruptions, with the objective of elucidating the physics of the eruption process. In particular, it was examine the viability of two specific eruption mechanisms, detailed in our proposal. These mechanisms are the "breakout model", and the "tether cutting model". During the second year, it was a significant progress in the goals to Data Sets Utilized. In the publications during this second year of the grant period, the data was used from the E W Imaging Telescope (EIT) and the Michelson Doppler Imager (MDI) instruments on SOHO, and from the Soft X-ray Telescope (SXT), Hard X-ray Telescope (HXT), and the Bragg Crystal Spectrometer (BCS) on Yooh.

  7. Scotch-Tape Mirror for Hard X-rays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The project is to build a grazing incidence mirror for hard X-rays (E>20 keV) using a “scotch-tape” design, in which a thin plastic tape with a...

  8. Adaptive Lobster-Eye Hard X-Ray Telescope Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address NASA needs for hard X-ray telescopes for starlight detection and wavefront analysis, Physical Optics Corporation (POC) proposes to develop an Adjustable...

  9. CdTe Focal Plane Detector for Hard X-Ray Focusing Optics

    Science.gov (United States)

    Seller, Paul; Wilson, Matthew D.; Veale, Matthew C.; Schneider, Andreas; Gaskin, Jessica; Wilson-Hodge, Colleen; Christe, Steven; Shih, Albert Y.; Inglis, Andrew; Panessa, Marco

    2015-01-01

    The demand for higher resolution x-ray optics (a few arcseconds or better) in the areas of astrophysics and solar science has, in turn, driven the development of complementary detectors. These detectors should have fine pixels, necessary to appropriately oversample the optics at a given focal length, and an energy response also matched to that of the optics. Rutherford Appleton Laboratory have developed a 3-side buttable, 20 millimeter x 20 millimeter CdTe-based detector with 250 micrometer square pixels (80 x 80 pixels) which achieves 1 kiloelectronvolt FWHM (Full-Width Half-Maximum) @ 60 kiloelectronvolts and gives full spectroscopy between 5 kiloelectronvolts and 200 kiloelectronvolts. An added advantage of these detectors is that they have a full-frame readout rate of 10 kilohertz. Working with NASA Goddard Space Flight Center and Marshall Space Flight Center, 4 of these 1 millimeter-thick CdTe detectors are tiled into a 2 x 2 array for use at the focal plane of a balloon-borne hard-x-ray telescope, and a similar configuration could be suitable for astrophysics and solar space-based missions. This effort encompasses the fabrication and testing of flight-suitable front-end electronics and calibration of the assembled detector arrays. We explain the operation of the pixelated ASIC readout and measurements, front-end electronics development, preliminary X-ray imaging and spectral performance, and plans for full calibration of the detector assemblies. Work done in conjunction with the NASA Centers is funded through the NASA Science Mission Directorate Astrophysics Research and Analysis Program.

  10. A Transmissive X-ray Polarimeter Design For Hard X-ray Focusing Telescopes

    CERN Document Server

    Li, Hong; Ji, Jianfeng; Deng, Zhi; He, Li; Zeng, Ming; Li, Tenglin; Liu, Yinong; Heng, Peiyin; Wu, Qiong; Han, Dong; Dong, Yongwei; Lu, Fangjun; Zhang, Shuangnan

    2015-01-01

    The X-ray Timing and Polarization (XTP) is a mission concept for a future space borne X-ray observatory and is currently selected for early phase study. We present a new design of X-ray polarimeter based on the time projection gas chamber. The polarimeter, placed above the focal plane, has an additional rear window that allows hard X-rays to penetrate (a transmission of nearly 80% at 6 keV) through it and reach the detector on the focal plane. Such a design is to compensate the low detection efficiency of gas detectors, at a low cost of sensitivity, and can maximize the science return of multilayer hard X-ray telescopes without the risk of moving focal plane instruments. The sensitivity in terms of minimum detectable polarization, based on current instrument configuration, is expected to be 3% for a 1mCrab source given an observing time of 10^5 s. We present preliminary test results, including photoelectron tracks and modulation curves, using a test chamber and polarized X-ray sources in the lab.

  11. Characterization of new hard X-ray Cataclysmic Variables

    CERN Document Server

    Bernardini, F; Falanga, M; Mukai, K; Matt, G; Bonnet-Bidaud, J -M; Masetti, N; Mouchet, M

    2012-01-01

    We aim at characterizing a sample of 9 new hard X-ray selected Cataclysmic Variable (CVs), to unambiguously identify them as magnetic systems of the Intermediate Polar (IP) type. We performed timing and spectral analysis by using X-ray, and simultaneous UV and optical data collected by XMM-Newton, complemented with hard X-ray data provided by INTEGRAL and Swift. The pulse arrival time were used to estimate the orbital periods. The X-ray spectra were fitted using composite models consisting of different absorbing columns and emission components. Strong X-ray pulses at the White Dwarf (WD) spin period are detected and found to decrease with energy. Most sources are spin-dominated systems in the X-rays, though four are beat dominated at optical wavelengths. We estimated the orbital period in all system (except for IGR J16500-3307), providing the first estimate for IGR J08390-4833, IGR J18308-1232, and IGR J18173-2509. All X-ray spectra are multi-temperature. V2069 Cyg and RX J0636+3535 posses a soft X-ray optica...

  12. Attosecond Hard X-ray Free Electron Laser

    Directory of Open Access Journals (Sweden)

    Sandeep Kumar

    2013-03-01

    Full Text Available In this paper, several schemes of soft X-ray and hard X-ray free electron lasers (XFEL and their progress are reviewed. Self-amplified spontaneous emission (SASE schemes, the high gain harmonic generation (HGHG scheme and various enhancement schemes through seeding and beam manipulations are discussed, especially in view of the generation of attosecond X-ray pulses. Our recent work on the generation of attosecond hard X-ray pulses is also discussed. In our study, the enhanced SASE scheme is utilized, using electron beam parameters of an XFEL under construction at Pohang Accelerator Laboratory (PAL. Laser, chicane and electron beam parameters are optimized to generate an isolated attosecond hard X-ray pulse at 0.1 nm (12.4 keV. The simulations show that the manipulation of electron energy beam profile may lead to the generation of an isolated attosecond hard X-ray of 150 attosecond pulse at 0.1 nm.

  13. Hard X-ray properties of magnetic cataclysmic variables

    CERN Document Server

    Scaringi, S; Norton, A J; Knigge, C; Hill, A B; Clark, D J; Dean, A J; McBride, V A; Barlow, E J; Bassani, L; Bazzano, A; Fiocchi, M; Landi, R

    2009-01-01

    Hard X-ray surveys have proven remarkably efficient in detecting intermediate polars and asynchronous polars, two of the rarest type of cataclysmic variable (CV). Here we present a global study of hard X-ray selected intermediate polars and asynchronous polars, focusing particularly on the link between hard X-ray properties and spin/orbital periods. To this end, we first construct a new sample of these objects by cross-correlating candidate sources detected in INTEGRAL/IBIS observations against catalogues of known CVs. We find 23 cataclysmic variable matches, and also present an additional 9 (of which 3 are definite) likely magnetic cataclysmic variables (mCVs) identified by others through optical follow-ups of IBIS detections. We also include in our analysis hard X-ray observations from Swift/BAT and SUZAKU/HXD in order to make our study more complete. We find that most hard X-ray detected mCVs have P_{spin}/P_{orb}<0.1 above the period gap. In this respect we also point out the very low number of detecte...

  14. Injection molded polymeric hard X-ray lenses

    DEFF Research Database (Denmark)

    Stöhr, Frederik; Simons, Hugh; Jakobsen, Anders Clemen;

    2015-01-01

    A novel and economical approach for fabricating compound refractive lenses for the purpose of focusing hard X-rays is described. A silicon master was manufactured by UV-lithography and deep reactive ion etching (DRIE). Sacrificial structures were utilized, which enabled accurate control of the et......A novel and economical approach for fabricating compound refractive lenses for the purpose of focusing hard X-rays is described. A silicon master was manufactured by UV-lithography and deep reactive ion etching (DRIE). Sacrificial structures were utilized, which enabled accurate control...... energies of 17 keV. A 55 µm long line focus with a minimal waist of 770 nm (FWHM) and a total lens transmittance of 32% were measured. Due to its suitability for cheap mass production, this highly efficient optics may find widespread use in hard X-ray instruments....

  15. X-ray Properties of an Unbiased Hard X-ray Detected Sample of AGN

    Science.gov (United States)

    Winter, Lisa M.; Mushotzky, Richard F.; Tueller, Jack; Markwardt, Craig

    2007-01-01

    The SWIFT gamma ray observatory's Burst Alert Telescope (BAT) has detected a sample of active galactic nuclei (AGN) based solely on their hard X-ray flux (14-195keV). In this paper, we present for the first time XMM-Newton X-ray spectra for 22 BAT AGXs with no previously analyzed X-ray spectra. If our sources are a representative sample of the BAT AGN, as we claim, our results present for the first time global X-ray properties of an unbiased towards absorption (n(sub H) = 0.03), AGN sample. We find 9/22 low absorption (n(sub H) 2.0 keV. Five of the complex sources (NGC 612, ESO 362-G018, MRK 417, ESO 506-G027, and NGC 6860) are classified as Compton-thick candidates. Further, we find four more sources (SWIFT J0641.3+3257, SWIFT J0911.2+4533, SWIFT J1200.8+0650, and NGC 4992) with properties consistent with the hidden/buried AGN reported by Ueda et al. (2007). Finally, we include a comparison of the XMM EPIC spectra with available SWIFT X-ray Telescope (XRT) observations. From these comparisons, we find 6/16 sources with varying column densities, 6/16 sources with varying power law indices, and 13/16 sources with varying fluxes, over periods of hours to months. Flux and power law index are correlated for objects where both parameters vary.

  16. Linking Jet Emission, X-ray States and Hard X-ray Tails in the Neutron Star X-ray Binary GX 17+2

    OpenAIRE

    Migliari, S.; Miller-Jones, J. C. A.; Fender, R. P.; Homan, J.; T. Di Salvo; Rothschild, R. E.; Rupen, M P; Tomsick, J. A.; Wijnands, R.; van der Klis, M.

    2007-01-01

    We present the results from simultaneous radio (Very Large Array) and X-ray (Rossi-X-ray Timing Explorer) observations of the Z-type neutron star X-ray binary GX~17+2. The aim is to assess the coupling between X-ray and radio properties throughout its three rapidly variable X-ray states and during the time-resolved transitions. These observations allow us, for the first time, to investigate quantitatively the possible relations between the radio emission and the presence of the hard X-ray tai...

  17. Towards hard X-ray imaging at GHz frame rate

    CERN Document Server

    Wang, Zhehui; Kapustinsky, J S; Kwiatkowski, K; Luo, S -N

    2012-01-01

    Gigahertz (GHz) imaging using hard X-rays ($\\gtrsim$ 10 keV) can be useful to high-temperature plasma experiments, as well as research using coherent photons from synchrotron radiation and X-ray free electron lasers. GHz framing rate can be achieved by using multiple cameras through multiplexing. The advantages and trade-offs of single-photon detection mode, when no more than one X-ray photon is detected per pixel, are given. Two possible paths towards X-ray imaging at GHz frame rates using a single camera are a.) Avalanche photodiode arrays of high-Z materials and b.) Microchannel plate photomultipliers in conjunction with materials with large indices of refraction.

  18. Towards hard X-ray imaging at GHz frame rate

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhehui [Los Alamos National Laboratory; Morris, Christopher [Los Alamos National Laboratory; Luo, Shengnian [Los Alamos National Laboratory; Kwiatkowski, Kris K. [Los Alamos National Laboratory; Kapustinsky, Jon S. [Los Alamos National Laboratory

    2012-05-02

    Gigahertz (GHz) imaging using hard X-rays ({approx}> 10 keV) can be useful to high-temperature plasma experiments, as well as research using coherent photons from synchrotron radiation and X-ray free electron lasers. GHz framing rate can be achieved by using multiple cameras through multiplexing. The advantages and trade-offs of single-photon detection mode, when no more than one X-ray photon is detected per pixel, are given. Two possible paths towards X-ray imaging at GHz frame rates using a single camera are (a) Avalanche photodiode arrays of high-Z materials and (b) Microchannel plate photomultipliers in conjunction with materials with large indices of refraction.

  19. Towards hard x-ray imaging at GHz frame rate

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zhehui; Morris, C. L.; Kapustinsky, J. S.; Kwiatkowski, K.; Luo, S.-N. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2012-10-15

    Gigahertz (GHz) imaging using hard x-rays ( Greater-Than-Or-Equivalent-To 10 keV) can be useful to high-temperature plasma experiments, as well as research and applications using coherent photons from synchrotron radiation and x-ray free electron lasers. GHz framing rate can be achieved by using multiple cameras through multiplexing. The advantages and trade-offs of single-photon detection mode, when no more than one x-ray photon is detected per pixel, are given. Two possible paths towards x-ray imaging at GHz frame rates using a single camera are: (a) avalanche photodiode arrays of high-Z materials and (b) microchannel plate photomultipliers in conjunction with materials with large indices of refraction.

  20. Towards hard x-ray imaging at GHz frame rate.

    Science.gov (United States)

    Wang, Zhehui; Morris, C L; Kapustinsky, J S; Kwiatkowski, K; Luo, S-N

    2012-10-01

    Gigahertz (GHz) imaging using hard x-rays (> or approximately equal to 10 keV) can be useful to high-temperature plasma experiments, as well as research and applications using coherent photons from synchrotron radiation and x-ray free electron lasers. GHz framing rate can be achieved by using multiple cameras through multiplexing. The advantages and trade-offs of single-photon detection mode, when no more than one x-ray photon is detected per pixel, are given. Two possible paths towards x-ray imaging at GHz frame rates using a single camera are: (a) avalanche photodiode arrays of high-Z materials and (b) microchannel plate photomultipliers in conjunction with materials with large indices of refraction.

  1. A hard X-ray laboratory for monochromator characterisation

    Energy Technology Data Exchange (ETDEWEB)

    Hamelin, B. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1997-04-01

    Since their installation at ILL during the 1970`s the ILL {gamma}-ray diffractometers have been intensively used in the development of neutron monochromators. However, the ageing of the sources and new developments in hard X-ray diffractometry lead to a decision at the end of 1995 to replace the existing {gamma}-ray laboratory with a hard X-ray laboratory, based on a 420 keV generator, making available in the long term several beam-lines for rapid characterisation of monochromator crystals. The facility is now installed and its characteristics and advantages are outlined. (author). 2 refs.

  2. Observing Galactic Black Hole Sources in Hard X-rays

    CERN Document Server

    Rao, A R

    2013-01-01

    Observations of Galactic black hole sources are traditionally done in the classical X-ray range (2 -- 10 keV) due to sensitivity constraints. Most of the accretion power, however, is radiated above 10 keV and the study of these sources in hard X-rays has the potential to unravel the radiation mechanisms operating at the inner region of the accretion disk, which is believed to be the seat of a myriad of fascinating features like jet emission, high frequency QPO emission etc. I will briefly summarise the long term hard X-ray observational features like spectral state identification, state transitions and hints of polarised emission, and describe the new insights that would be provided by the forthcoming Astrosat satellite, particularly emphasising the contributions expected from the CZT-Imager payload.

  3. Fourier-Transform Ghost Imaging with Hard X Rays

    Science.gov (United States)

    Yu, Hong; Lu, Ronghua; Han, Shensheng; Xie, Honglan; Du, Guohao; Xiao, Tiqiao; Zhu, Daming

    2016-09-01

    Knowledge gained through x-ray crystallography fostered structural determination of materials and greatly facilitated the development of modern science and technology in the past century. However, it is only applied to crystalline structures and cannot resolve noncrystalline materials. Here we demonstrate a novel lensless Fourier-transform ghost imaging method with pseudothermal hard x rays that extends x-ray crystallography to noncrystalline samples. By measuring the second-order intensity correlation function of the light, Fourier-transform diffraction pattern of a complex amplitude sample is achieved at the Fresnel region in our experiment and the amplitude and phase distributions of the sample in the spatial domain are retrieved successfully. For the first time, ghost imaging is experimentally realized with x rays. Since a highly coherent x-ray source is not required, the method can be implemented with laboratory x-ray sources and it also provides a potential solution for lensless diffraction imaging with fermions, such as neutrons and electrons where intensive coherent sources usually are not available.

  4. Fourier-transform Ghost Imaging with Hard X-rays

    CERN Document Server

    Yu, Hong; Han, Shensheng; Xie, Honglan; Du, Guohao; Xiao, Tiqiao; Zhu, Daming

    2016-01-01

    Knowledge gained through X-ray crystallography fostered structural determination of materials and greatly facilitated the development of modern science and technology in the past century. Atomic details of sample structures is achievable by X-ray crystallography, however, it is only applied to crystalline structures. Imaging techniques based on X-ray coherent diffraction or zone plates are capable of resolving the internal structure of non-crystalline materials at nanoscales, but it is still a challenge to achieve atomic resolution. Here we demonstrate a novel lensless Fourier-transform ghost imaging method with pseudo-thermal hard X-rays by measuring the second-order intensity correlation function of the light. We show that high resolution Fourier-transform diffraction pattern of a complex structure can be achieved at Fresnel region, and the amplitude and phase distributions of a sample in spatial domain can be retrieved successfully. The method of lensless X-ray Fourier-transform ghost imaging extends X-ray...

  5. Balloon-borne gamma-ray polarimetry

    CERN Document Server

    Pearce, Mark

    2011-01-01

    The physical processes postulated to explain the high-energy emission mechanisms of compact astrophysical sources often yield polarised soft gamma rays (X-rays). PoGOLite is a balloon-borne polarimeter operating in the 25-80 keV energy band. The polarisation of incident photons is reconstructed using Compton scattering and photoelectric absorption in an array of phoswich detector cells comprising plastic and BGO scintillators, surrounded by a BGO side anticoincidence shield. The polarimeter is aligned to observation targets using a custom attitude control system. The maiden balloon flight is scheduled for summer 2011 from the Esrange Space Centre with the Crab and Cygnus X-1 as the primary observational targets.

  6. Dark Matter Detection with Hard X-ray Telescopes

    CERN Document Server

    Jeltema, Tesla E

    2011-01-01

    We analyze the impact of future hard X-ray observations on the search for indirect signatures of particle dark matter in large extragalactic systems such as nearby clusters or groups of galaxies. We argue that the hard X-ray energy band falls squarely at the peak of the inverse Compton emission from electrons and positrons produced by dark matter annihilation or decay for a large class of dark matter models. Specifically, the most promising are low-mass models with a hard electron-positron annihilation final state spectrum and intermediate-mass models with a soft electron-positron spectrum. We find that constraints on dark matter models similar to the current constraints from the Fermi Gamma-Ray Space Telescope will be close to the limit of the sensitivity of the near-term hard X-ray telescopes NuSTAR and ASTRO-H for relatively long observations, but an instrument similar to the Wide Field Imager proposed for the International X-ray Observatory would allow significant gains to be made. In the future, the abil...

  7. Imaging of reconnection processes in hard X-rays

    NARCIS (Netherlands)

    Svestka, Z.; Poletto, G.

    1984-01-01

    The Hard X-ray Spectrometer aboard the SMM detected several events of energy release late in the development of two-ribbon flares. One such event, at 21:12 UT on 21 May, 1980 ( 20 min after the flare onset and 15 min after the peak of the impulsive phase) is studied in detail. The site of new bright

  8. Crab Nebula Variations in Hard X-rays

    Science.gov (United States)

    Wilson-Hodge, Colleen A.

    2012-01-01

    The Crab Nebula was surprisingly variable from 2001-2010, with less variability before 2001 and since mid-2010. We presented evidence for spectral softening from RXTE, Swift/BAT, and Fermi GBM during the mid-2008-2010 flux decline. We see no clear connections between the hard X-ray variations and the GeV flares

  9. Solar hard X-rays and gamma-rays

    Institute of Scientific and Technical Information of China (English)

    GAN; Weiqun(甘为群); CHANG; Jin(常进); LI; Youping(李友平); LIN; Chunmei(林春梅)

    2002-01-01

    We briefly introduce our recent work on the spectral evolution of energetic protons, the beam property of accelerated electrons, the gamma-ray flare classification, the temporal features of the annihilation line, the hard X-ray delayed events, the hydrodynamic process, and the continuum emission in solar flares.

  10. Hard X-ray mirrors for Nuclear Security

    Energy Technology Data Exchange (ETDEWEB)

    Descalle, M. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brejnholt, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hill, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Decker, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Alameda, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Soufli, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Pivovaroff, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Pardini, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-01-07

    Research performed under this LDRD aimed to demonstrate the ability to detect and measure hard X-ray emissions using multilayer X-ray reflective optics above 400 keV, to enable the development of inexpensive and high-accuracy mirror substrates, and to investigate applications of hard X-ray mirrors of interest to the nuclear security community. Experiments conducted at the European Synchrotron Radiation Facility demonstrated hard X-ray mirror reflectivity up to 650 keV for the first time. Hard X-ray optics substrates must have surface roughness under 3 to 4 Angstrom rms, and three materials were evaluated as potential substrates: polycarbonates, thin Schott glass and a new type of flexible glass called Willow Glass®. Chemical smoothing and thermal heating of the surface of polycarbonate samples, which are inexpensive but have poor intrinsic surface characteristics, did not yield acceptable surface roughness. D263 Schott glass was used for the focusing optics of the NASA NuSTAR telescope. The required specialized hardware and process were costly and motivated experiments with a modified non-contact slumping technique. The surface roughness of the glass was preserved and the process yielded cylindrical shells with good net shape pointing to the potential advantage of this technique. Finally, measured surface roughness of 200 and 130 μm thick Willow Glass sheets was between 2 and 2.5 A rms. Additional results of flexibility tests and multilayer deposition campaigns indicated it is a promising substrate for hard X-ray optics. The detection of U and Pu characteristics X-ray lines and gamma emission lines in a high background environment was identified as an area for which X-ray mirrors could have an impact and where focusing optics could help reduce signal to noise ratio by focusing signal onto a smaller detector. Hence the first one twelvetant of a Wolter I focusing optics for the 90 to 140 keV energy range based on aperiodic multilayer coating was designed. Finally

  11. X-ray Measurements of Black Hole X-ray Binary Source GRS 1915+105 and the Evolution of Hard X-ray Spectrum

    Indian Academy of Sciences (India)

    R. K. Manchanda

    2000-06-01

    We report the spectral measurement of GRS 1915+105 in the hard X-ray energy band of 20-140keV. The observations were made on March 30th, 1997 during a quiescent phase of the source. We discuss the mechanism of emission of hard X-ray photons and the evolution of the spectrum by comparing the data with earlier measurements and an axiomatic model for the X-ray source.

  12. Characterization of New Hard X-ray Cataclysmic Variables

    Science.gov (United States)

    Bernardini, F.; deMartino, D.; Falanga, M.; Mukai, K.; Matt, G.; Bonnet-Bidaud, J.-M.; Masetti, N.; Mouchet, M.

    2012-01-01

    Aims. We aim at characterizing a sample of nine new hard X-ray selected Cataclysmic Variable (CVs), to unambiguously identify them as magnetic systems of the Intermediate Polar (IP) type. Methods. We performed detailed timing and spectral analysis by using X-ray, and simultaneous UV and optical data collected by XMM-Newton, complemented with hard X-ray data provided by INTEGRAL and Swift. The pulse arrival time were used to estimate the orbital periods. The broad band X-ray spectra were fitted using composite models consisting of different absorbing columns and emission components. Results. Strong X-ray pulses at the White Dwarf (WD) spin period are detected and found to decrease with energy. Most sources are spin-dominated systems in the X-rays, though four are beat dominated at optical wavelengths. We estimated the orbital period in all system (except for IGR J16500-3307), providing the first estimate for IGRJ08390-4833, IGRJ18308-1232, and IGR J18173-2509. All X-ray spectra are multi-temperature. V2069 Cyg and RX J0636+3535 poses a soft X-ray optically thick component at kT approx. 80 eV. An intense K (sub alpha) Fe line at 6.4 keV is detected in all sources. An absorption edge at 0.76 keV from OVII is detected in IGR J08390-4833. The WD masses and lower limits to the accretion rates are also estimated. Conclusions. We found all sources to be IPs. IGR J08390-4833, V2069 Cyg, and IGR J16500-3307 are pure disc accretors, while IGR J18308-1232, IGR J1509-6649, IGR J17195-4100, and RX J0636+3535 display a disc-overflow accretion mode. All sources show a temperature gradient in the post-shock regions and a highly absorbed emission from material located in the pre-shock flow which is also responsible for the X-ray pulsations. Reflection at the WD surface is likely the origin of the fluorescent iron line. There is an increasing evidence for the presence of a warm absorber in IPs, a feature that needs future exploration. The addition of two systems to the subgroup of

  13. Deducing Electron Properties From Hard X-Ray Observations

    OpenAIRE

    Kontar, E.P.; Brown, J. C.; Emslie, A. G.; Hajdas, W.; Holman, G. D.; Hurford, G. J.; Kasparova, J.; Mallik, P. C. V.; Massone, A. M.; McConnell, M. L.; M. Piana; Prato, M.; Schmahl, E. J.; Suarez-Garcia, E.

    2011-01-01

    X-radiation from energetic electrons is the prime diagnostic of flare-accelerated electrons. The observed X-ray flux (and polarization state) is fundamentally a convolution of the cross-section for the hard X-ray emission process(es) in question with the electron distribution function, which is in turn a function of energy, direction, spatial location and time. To address the problems of particle propagation and acceleration one needs to infer as much information as possible on this electron ...

  14. A hard X-ray polarimeter utilizing Compton scattering

    Science.gov (United States)

    Sakurai, H.; Noma, M.; Niizeki, H.

    1991-01-01

    The paper describes a 50-cm-diam prototype of a novel Compton-scattering-type polarimeter for hard X-rays in the energy range 30-100 keV. The characteristics of the prototype polarimeter were investigated for various conditions. It was found that, with polarized X-rays from a simple polarizer, the detection efficiency and the modulation factor of the polarimeter with a 40-mm thick scatterer were 3.2 percent and 0.57 percent, respectively, at about 60 keV.

  15. Complete Hard X-Ray Surveys, AGN Luminosity Functions and the X-Ray Background

    Science.gov (United States)

    Tueller, Jack

    2011-01-01

    AGN are believed to make up most of the Cosmic X-Ray Background (CXB) above a few keV, but this background cannot be fully resolved at energies less than 10 keV due to absorption. The Swift/BAT and INTEGRAL missions are performing the first complete hard x-ray surveys with minimal bias due to absorption. The most recent results for both missions will be presented. Although the fraction of the CXB resolved by these surveys is small, it is possible to derive unbiased number counts and luminosity functions for AGN in the local universe. The survey energy range from 15-150 keV contains the important reflection and cutoff spectral features dominate the shape of the AGN contribution to the CXB. Average spectral characteristics of survey detected AGN will be presented and compared with model distributions. The numbers of hard x-ray blazars detected in these surveys are finally sufficient to estimate this important component's contribution the cosmic background. Constraints on CXB models and their significance will be discussed.

  16. Discovery of Diffuse Hard X-ray Emission Around Jupiter

    Science.gov (United States)

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

    2009-09-01

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

  17. Observational Aspects of Hard X-ray Polarimetry

    Science.gov (United States)

    Chattopadhyay, Tanmoy

    2016-04-01

    Sensitive polarization measurements in X-ray may address a wealth of astrophysical phenomena, which so far remain beyond our understanding through available X-ray spectroscopic, imaging, and timing studies. Though scientific potential of X-ray polarimetry was realized long ago, there has not been any significant advancement in this field for the last four decades since the birth of X-ray astronomy. The only successful polarization measurement in X-rays dates back to 1976, when a Bragg polarimeter onboard OSO-8 measured polarization of Crab nebula. Primary reason behind the lack in progress is its extreme photon hungry nature, which results in poor sensitivity of the polarimeters. Recently, in the last decade or so, with the advancement in detection technology, X-ray polarimetry may see a significant progress in near future, especially in soft X-rays with the invention of photoelectron tracking polarimeters. Though photoelectric polarimeters are expected to provide sensitive polarization measurements of celestial X-ray sources, they are sensitive only in soft X-rays, where the radiation from the sources is dominated by thermal radiation and therefore expected to be less polarized. On the other hand, in hard X-rays, sources are ex-pected to be highly polarized due to the dominance of nonthermal emission over its thermal counterpart. Moreover, polarization measurements in hard X-rays promises to address few interesting scientific issues regarding geometry of corona for black hole sources, emission mechanism responsible for the higher energy peak in the blazars, accretion geometry close to the magnetic poles in accreting neutron star systems and acceleration mechanism in solar flares. Compton polarimeters provide better sensitivity than photoelectric polarimeters in hard X-rays with a broad energy band of operation. Recently, with the development of hard X-ray focusing optics e.g. NuSTAR, Astro-H, it is now possible to conceive Compton polarimeters at the focal plane

  18. Hard x-ray nanofocusing by multilayer Laue lenses

    International Nuclear Information System (INIS)

    Multilayer Laue lens (MLL) is a new class of x-ray optics that offer great promise for achieving nanometre-level spatial resolution by focusing hard x-rays. Fabricating an MLL via thin-film deposition provides the means to achieve a linear Fresnel-zone plate structure with zone widths below 1 nm, while retaining a virtually limitless aspect ratio. Despite its similarity to the Fresnel-zone plate, MLL exhibits categorically distinctive focusing properties and their fabrication comes with a wide array of challenges. This article provides a comprehensive review of advances in MLLs, and includes extensive theoretical modelling on focusing performance, discussion on fabrication challenges, their current capabilities and notable results from x-ray focusing experiments. (topical review)

  19. The hard x-ray spectrum of SN 1987A

    International Nuclear Information System (INIS)

    The authors report the discovery of hard x-rays in the energy range from 20 to 350 keV. The hard x-rays were first observed on August 10, 1987 and thereafter SN 1987A became the main target of the observatory. The measured spectrum is extremely hard. At high energies the photon spectrum has a power law index of ∼ 1.4. At lower energies the spectrum becomes flatter and there is indication of a cut-off below 25 keV. The luminosity in the above energy band is ∼ 2 x 1038 erg/s. The flux shows little variation between August 10 and beginning of October

  20. Submicron hard X-ray fluorescence imaging of synthetic elements

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Mark P., E-mail: mjensen@anl.gov [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Aryal, Baikuntha P. [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Department of Chemistry, University of Chicago, Chicago, IL 60637 (United States); Gorman-Lewis, Drew [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Paunesku, Tatjana [Department of Radiation Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 (United States); Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 (United States); Lai, Barry; Vogt, Stefan [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Woloschak, Gayle E. [Department of Radiation Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 (United States); Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 (United States)

    2012-04-13

    Highlights: Black-Right-Pointing-Pointer Actinide elements are mapped with L-edge X-rays and better than 400 nm resolution. Black-Right-Pointing-Pointer A typical detection limit was 2.9 Multiplication-Sign 10{sup -20} moles Pu {mu}m{sup -2}. Black-Right-Pointing-Pointer XANES measurements provide chemical information in 0.1 {mu}m{sup 2} spots. Black-Right-Pointing-Pointer Selection of materials for encapsulation is important for avoiding interferences. - Abstract: Synchrotron-based X-ray fluorescence microscopy (XFM) using hard X-rays focused into sub-micron spots is a powerful technique for elemental quantification and mapping, as well as microspectroscopic measurements such as {mu}-XANES (X-ray absorption near edge structure). We have used XFM to image and simultaneously quantify the transuranic element plutonium at the L{sub 3} or L{sub 2}-edge as well as Th and lighter biologically essential elements in individual rat pheochromocytoma (PC12) cells after exposure to the long-lived plutonium isotope {sup 242}Pu. Elemental maps demonstrate that plutonium localizes principally in the cytoplasm of the cells and avoids the cell nucleus, which is marked by the highest concentrations of phosphorus and zinc, under the conditions of our experiments. The minimum detection limit under typical acquisition conditions with an incident X-ray energy of 18 keV for an average 202 {mu}m{sup 2} cell is 1.4 fg Pu or 2.9 Multiplication-Sign 10{sup -20} moles Pu {mu}m{sup -2}, which is similar to the detection limit of K-edge XFM of transition metals at 10 keV. Copper electron microscopy grids were used to avoid interference from gold X-ray emissions, but traces of strontium present in naturally occurring calcium can still interfere with plutonium detection using its L{sub {alpha}} X-ray emission.

  1. Hard X-ray Imaging Polarimeter for PolariS

    Science.gov (United States)

    Hayashida, Kiyoshi

    2016-07-01

    We present the current status of development of hard X-ray imaging polarimeters for the small satellite mission PolariS. The primary aim of PolariS is hard X-ray (10-80keV) polarimetry of sources brighter than 10mCrab. Its targets include stellar black holes, neutron stars, super nova remnants, and active galactic nuclei. This aim is enabled with three sets of hard X-ray telescopes and imaging polarimeters installed on their focal planes. The imaging polarimeter consists of two kinds of (plastic and GSO) scintillator pillars and multi-anode photo multiplier tubes (MAPMTs). When an X-ray photon incident to a plastic scintillator cause a Compton scattering, a recoiled electron makes a signal on the corresponding MAPMT pixel, and a scatted X-rays absorbed in surrounding GSO makes another signal. This provide information on the incident position and the scattered direction. The latter information is employed for polarimetry. For 20keV X-ray incidence, the recoiled electron energy is as low as 1keV. Thus, the performance of this imaging polarimeter is primarily determined by the efficiency that we can detect low level signal of recoiled electrons generated in plastic scintillators. The efficiency could depend on multiple factors, e.g. quenching of light in scintillators, electric noise, pedestal error, cross talk of the lights to adjacent MAPMT pixels, MAPMT dark current etc. In this paper, we examined these process experimentally and optimize the event selection algorithm, in which single photo-electron events are selected. We then performed an X-ray (10-80keV monochromatic polarized beam) irradiation test at a synchrotron facility. The modulation contrast (M) is about 60% in 15-80keV range. We succeeded in detecting recoiled electrons for 10-80keV X-ray incidence, though detection efficiency is lower at lowest end of the energy range. Expected MDP will also be shown.

  2. Method and apparatus for micromachining using hard X-rays

    Science.gov (United States)

    Siddons, David Peter; Johnson, Erik D.; Guckel, Henry; Klein, Jonathan L.

    1997-10-21

    An X-ray source such as a synchrotron which provides a significant spectral content of hard X-rays is used to expose relatively thick photoresist such that the portions of the photoresist at an exit surface receive at least a threshold dose sufficient to render the photoresist susceptible to a developer, while the entrance surface of the photoresist receives an exposure which does not exceed a power limit at which destructive disruption of the photoresist would occur. The X-ray beam is spectrally shaped to substantially eliminate lower energy photons while allowing a substantial flux of higher energy photons to pass through to the photoresist target. Filters and the substrate of the X-ray mask may be used to spectrally shape the X-ray beam. Machining of photoresists such as polymethylmethacrylate to micron tolerances may be obtained to depths of several centimeters, and multiple targets may be exposed simultaneously. The photoresist target may be rotated and/or translated in the beam to form solids of rotation and other complex three-dimensional structures.

  3. NuSTAR Hard X-ray Survey of the Galactic Center Region. I. Hard X-ray Morphology and Spectroscopy of the Diffuse Emission

    DEFF Research Database (Denmark)

    Mori, Kaya; Hailey, Charles J.; Krivonos, Roman;

    2015-01-01

    We present the first sub-arcminute images of the Galactic Center above 10 keV, obtained with NuSTAR. NuSTAR resolves the hard X-ray source IGR J17456-2901 into non-thermal X-ray filaments, molecular clouds, point sources, and a previously unknown central component of hard X-ray emission (CHXE). N...

  4. Observing Solar Hard X-rays from Heliospheric Orbits

    Science.gov (United States)

    Hurford, Gordon J.; Benz, A.; Dennis, B.; Krucker, S.; Limousin, O.; Lin, R.; Vilmer, N.

    2010-05-01

    The coming decade provides two opportunities to acquire a different observational perspective on solar hard x-ray emission. Both ESA's Solar Orbiter and NASA's Solar Probe Plus missions will be in heliocentric orbits with perihelia of 0.28 au and 0.05 au respectively. This poster indicates the unique scientific advantages of hard x-ray imaging/spectroscopy observations from such platforms. These advantages stem from three factors: First, in combination with other payload elements, the hard x-rays provide the ability to observationally link accelerated electrons at the Sun to radio observations of the propagating electrons and to direct observations of in situ electrons. Second, the substantial gain in sensitivity afforded by close-in vantage points enables exploration of the origin of non-flare associated SEP events to be studied and the character of quiescent active-region heating and electron acceleration to be evaluated. Third, the different observational perspectives provided by the heliocentric orbits compared to low-Earth orbits enable improved separation of coronal and footpoint sources as well as measurements of the isotropy of the x-ray emission. Despite the limited payload resources (mass, power, telemetry) afforded by such missions, scientifically effective hard x-ray imaging spectroscopy from 5 keV to 150 keV is still feasible. The Spectrometer/Telescope for Imaging X-rays (STIX), accepted as part of the Solar Orbiter payload, combines high spectral resolution ( 1 keV FWHM at 10 keV) with spatial resolution as good as 1500 km, and can efficiently encode the data for several hundred optimized images per hour within a modest telemetry allocation and 4 kg / 4 watt budget. The X-ray Imaging Spectrometer (XIS) proposed for Solar Probe Plus, views the Sun through its thermal shield. It also features high spectral resolution from 6 to 150 keV and spatial resolution of 1500 km at perihelion. The poster describes the imaging principles and current configurations

  5. Observation of polarized hard X-ray emission from the Crab by the PoGOLite Pathfinder

    Science.gov (United States)

    Chauvin, M.; Florén, H.-G.; Jackson, M.; Kamae, T.; Kawano, T.; Kiss, M.; Kole, M.; Mikhalev, V.; Moretti, E.; Olofsson, G.; Rydström, S.; Takahashi, H.; Iyudin, A.; Arimoto, M.; Fukazawa, Y.; Kataoka, J.; Kawai, N.; Mizuno, T.; Ryde, F.; Tajima, H.; Takahashi, T.; Pearce, M.

    2016-02-01

    We have measured the linear polarization of hard X-ray emission from the Crab in a previously unexplored energy interval, 20-120 keV. The introduction of two new observational parameters, the polarization fraction and angle stands to disentangle geometrical and physical effects, thereby providing information on the pulsar wind geometry and magnetic field environment. Measurements are conducted using the PoGOLite Pathfinder - a balloon-borne polarimeter. Polarization is determined by measuring the azimuthal Compton scattering angle of incident X-rays in an array of plastic scintillators housed in an anticoincidence well. The polarimetric response has been characterized prior to flight using both polarized and unpolarized calibration sources. We address possible systematic effects through observations of a background field. The measured polarization fraction for the integrated Crab light curve is 18.4^{+9.8}_{-10.6} per cent, corresponding to an upper limit (99 per cent credibility) of 42.4 per cent, for a polarization angle of (149.2 ± 16.0)°.

  6. Building Large Area CZT Imaging Detectors for a Wide-Field Hard X-ray Telescope - ProtoEXIST1

    CERN Document Server

    Hong, J; Grindlay, J; Chammas, N; Barthelemy, S; Baker, R; Gehrels, N; Nelson, K E; Labov, S; Collins, J; Cook, W R; McLean, R; Harrison, F

    2009-01-01

    We have constructed a moderately large area (32 cm2), fine pixel (2.5 mm pixel, 5 mm thick) CZT imaging detector which constitutes the first section of a detector module (256 cm2) developed for a balloon-borne wide-field hard X-ray telescope, ProtoEXIST1. ProtoEXIST1 is a prototype for the High Energy Telescope (HET) in the Energetic X-ray imaging Survey Telescope (EXIST), a next generation space-borne multi-wavelength telescope. We have constructed a large (nearly gapless) detector plane through a modularization scheme by tiling of a large number of 2 cm x 2 cm CZT crystals. Our innovative packaging method is ideal for many applications such as coded-aperture imaging, where a large, continuous detector plane is desirable for the optimal performance. Currently we have been able to achieve an energy resolution of 3.2 keV (FWHM) at 59.6 keV on average, which is exceptional considering the moderate pixel size and the number of detectors in simultaneous operation. We expect to complete two modules (512 cm2) withi...

  7. A new hard X-ray transient discovered by INTEGRAL

    DEFF Research Database (Denmark)

    Gibaud, L.; Bazzano, A.; Bozzo, E.;

    2011-01-01

    INTEGRAL discovered a new hard X-ray transient, IGR J17498-2921, during the observations performed from 2011-08-11 22:45 to 2011-08-12 05:54 UTC. The source is detected in the IBIS/ISGRI mosaic at a preliminary significance level of 11 and 9 sigma in the 20-40 keV and 40-80 keV energy bands...

  8. Hard X-ray emission of Sco X-1

    CERN Document Server

    Revnivtsev, Mikhail G; Churazov, Eugene M; Krivonos, Roman A

    2014-01-01

    We study hard X-ray emission of the brightest accreting neutron star Sco X-1 with INTEGRAL observatory. Up to now INTEGRAL have collected ~4 Msec of deadtime corrected exposure on this source. We show that hard X-ray tail in time average spectrum of Sco X-1 has a power law shape without cutoff up to energies ~200-300 keV. An absence of the high energy cutoff does not agree with the predictions of a model, in which the tail is formed as a result of Comptonization of soft seed photons on bulk motion of matter near the compact object. The amplitude of the tail varies with time with factor more than ten with the faintest tail at the top of the so-called flaring branch of its color-color diagram. We show that the minimal amplitude of the power law tail is recorded when the component, corresponding to the innermost part of optically thick accretion disk, disappears from the emission spectrum. Therefore we show that the presence of the hard X-ray tail may be related with the existence of the inner part of the optica...

  9. The Correlation between Hard X-Ray Peak Flux and Soft X-Ray Peak Flux in the Outburst Rise of Low-Mass X-Ray Binaries

    NARCIS (Netherlands)

    W. Yu; M. van der Klis; R.P. Fender

    2004-01-01

    We have analyzed Rossi X-Ray Timing Explorer pointed observations of the outbursts of black hole and neutron star soft X-ray transients in which an initial low/hard state, or ``island'' state, followed by a transition to a softer state was observed. In three sources-the black hole transient XTE J155

  10. 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.

  11. 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.

  12. X-ray microscopy of soft and hard human tissues

    Energy Technology Data Exchange (ETDEWEB)

    Müller, Bert, E-mail: bert.mueller@unibas.ch; Schulz, Georg, E-mail: georg.schulz@unibas.ch; Deyhle, Hans, E-mail: hans.deyhle@unibas.ch; Stalder, Anja K., E-mail: anja.stalder@unibas.ch; Ilgenstein, Bernd, E-mail: bernd.ilgenstein@unibas.ch; Holme, Margaret N., E-mail: m.holme@imperial.ac.uk; Hieber, Simone E., E-mail: simone.hieber@unibas.ch [Biomaterials Science Center (BMC), University of Basel, c/o University Hospital, 4031 Basel (Switzerland); Weitkamp, Timm, E-mail: weitkamp@synchrotron-soleil.fr [Beamline ANATOMIX, Synchrotron Soleil, L’Orme des Merisiers, Saint Aubin - B.P. 48, 91192 Gif sur Yvette (France); Beckmann, Felix, E-mail: felix.beckmann@hzg.de [Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, 21502 Geesthacht, c/o HZG at DESY, Notkestr. 85, 22607 Hamburg (Germany)

    2016-01-28

    The simultaneous post mortem visualization of soft and hard tissues using absorption-based CT remains a challenge. If the photon energy is optimized for the visualization of hard tissue, the surrounding soft tissue components are almost X-ray transparent. Therefore, the combination with other modalities such as phase-contrast CT, magnetic resonance microscopy, and histology is essential to detect the anatomical features. The combination of the 2D and 3D data sets using sophisticated segmentation and registration tools allows for conclusions about otherwise inaccessible anatomical features essential for improved patient treatments.

  13. X-ray microscopy of soft and hard human tissues

    International Nuclear Information System (INIS)

    The simultaneous post mortem visualization of soft and hard tissues using absorption-based CT remains a challenge. If the photon energy is optimized for the visualization of hard tissue, the surrounding soft tissue components are almost X-ray transparent. Therefore, the combination with other modalities such as phase-contrast CT, magnetic resonance microscopy, and histology is essential to detect the anatomical features. The combination of the 2D and 3D data sets using sophisticated segmentation and registration tools allows for conclusions about otherwise inaccessible anatomical features essential for improved patient treatments

  14. The Correlation between Hard X-Ray Peak Flux and Soft X-Ray Peak Flux in the Outburst Rise of Low-Mass X-Ray Binaries

    OpenAIRE

    Yu, W.; Klis, van der, M.; Fender, R. P.

    2004-01-01

    We have analyzed Rossi X-Ray Timing Explorer pointed observations of the outbursts of black hole and neutron star soft X-ray transients in which an initial low/hard state, or ``island'' state, followed by a transition to a softer state was observed. In three sources-the black hole transient XTE J1550-564, the neutron star transient Aquila X-1, and the quasi-persistent neutron star low-mass X-ray binary 4U 1705-44-two such outbursts were found. We find that the flux of the soft X-ray peak, whi...

  15. Hard X-Ray Modulation Telescope(HXMT) Mission

    Institute of Scientific and Technical Information of China (English)

    LI Tipei; ZHANG Shuangnan; LU Fangjun

    2006-01-01

    The HXMT mission concept consists of a slat-collimated hard X-ray detector assembly sensitive in 20~250 keV with a collection area of about 5000 cm2. Based on the reconstruction technique by direct demodulation developed in recent years, HXMT is mainly devoted to performing a hard X-ray all-sky imaging survey with both high sensitivity and high spatial resolution. It can also be used to make pointed observations of X-ray sources to study their spectroscopic and temporal properties in details. The main detector of HXMT consists of 18 individual cylindrical NaI(T1)/CsI(Na) phoswich modules, each with anarea of 283.5 cm2 and a field of view of 5.7°× 1.1° (FWHM). Its spatial resolution and position accuracy are 5′ and 1′ by using the direct demodulation in 1994, and in 2000 its feasibility and technical demonstration study was selected as a project under the Major State Basic Research Program of China. In October 2005, this project entered the full design phase and was listed as a candidate for the first dedicated astronomy satellite around 2010. We are now also considering secondary low energy instruments for this satellite.

  16. A novel compact Tokamak Hard X-ray diagnostic detector

    Institute of Scientific and Technical Information of China (English)

    曹靖; 蒋春雨; 赵艳凤; 杨青巍; 阴泽杰

    2015-01-01

    A compact X-ray detector based on the lutetium yttrium oxyorthosilicate scintillator (LYSO) and silicon photomultiplier (SiPM) has been designed and fabricated for the hard X-ray diagnosis on the HL 2A and HL 2M Tokamak devices. The LYSO scintillator and SiPM in small dimensions were combined in a heat shrink tube package, making the detector compact and integrative. The Monte Carlo particle transport simulation tool, Geant4, was utilized for the design of the detector for the hard X-ray from 10 keV to 200 keV and the best structure scheme was presented. Finally, the detector was used to measure the photon spectrum of a 137Cs gamma source with a pre-amplifier and a multichannel amplitude analyzer. The measured spectrum is consistent with the theoretic spectrum, it has shown that the energy resolution of the detector is less than 14.8%at an energy of 662 keV.

  17. Cost effective segmented scintillating converters for hard x-rays

    International Nuclear Information System (INIS)

    Thick segmented scintillating converters coupled to optical imaging detectors offer the advantage of large area, high stopping power sensors for high energy X-ray digital imaging. The recent advent of high resolution and solid state optical sensors such as amorphous silicon arrays and CCD optical imaging detectors makes it feasible to build large, cost effective imaging arrays. This technology, however, shifts the sensor cost burden to the segmented scintillators needed for imaging. The required labor intensive fabrication of high resolution, large area hard X-ray converters results in high cost and questionable manufacturability on a large scale. The authors report on recent research of a new segmented X-ray imaging converter. This converter is fabricated using vacuum injection and crystal growth methods to induce defect free, high density scintillating fibers into a collimator matrix. This method has the potential to fabricate large area (>400 cm2), thick (10 cm) segmented scintillators. Spatial resolution calculations of these scintillator injected collimators show that the optical light spreading is significantly reduced compared to single crystalline scintillators and sub-millimeter resolution can be achieved for 10 MeV photons. They have produced 2.5 cm thick converters and sub-millimeter resolution X-ray images acquired with the segmented converter coupled to a cooled CCD camera provided the resolution to characterize the converter efficiency and noise. The proposed concept overcomes the above mentioned limitations by producing a cost-effective technique of fabricating large area X-ray scintillator converters with high stopping power and high spatial resolution. This technology will readily benefit diverse fields such as particle physics, astronomy, medicine, as well as industrial nuclear and non-destructive testing

  18. Deducing Electron Properties From Hard X-Ray Observations

    CERN Document Server

    Kontar, E P; Emslie, A G; Hajdas, W; Holman, G D; Hurford, G J; Kasparova, J; Mallik, P C V; Massone, A M; McConnell, M L; Piana, M; Prato, M; Schmahl, E J; Suarez-Garcia, E

    2011-01-01

    X-radiation from energetic electrons is the prime diagnostic of flare-accelerated electrons. The observed X-ray flux (and polarization state) is fundamentally a convolution of the cross-section for the hard X-ray emission process(es) in question with the electron distribution function, which is in turn a function of energy, direction, spatial location and time. To address the problems of particle propagation and acceleration one needs to infer as much information as possible on this electron distribution function, through a deconvolution of this fundamental relationship. This review presents recent progress toward this goal using spectroscopic, imaging and polarization measurements, primarily from the \\textit{Reuven Ramaty High Energy Solar Spectroscopic Imager} ({\\em RHESSI}). Previous conclusions regarding the energy, angular (pitch angle) and spatial distributions of energetic electrons in solar flares are critically reviewed. We discuss the role and the observational evidence of several radiation processe...

  19. Angular resolution measurements at SPring-8 of a hard X-ray optic for the New Hard X-ray Mission

    OpenAIRE

    Spiga, D.; Raimondi, L.; Furuzawa, A.; Basso, S; Binda, R.; Borghi, G.; Cotroneo, V.; Grisoni, G.; Kunieda, H.; Marioni, F.; Matsumoto, H; Mori, H.; Miyazawa, T.; B. Negri; Orlandi, A.

    2015-01-01

    The realization of X-ray telescopes with imaging capabilities in the hard (> 10 keV) X-ray band requires the adoption of optics with shallow (10 m shall be produced and tested. Full-illumination tests of such mirrors are usually performed with on- ground X-ray facilities...

  20. Deducing Electron Properties from Hard X-ray Observations

    Science.gov (United States)

    Kontar, E. P.; Brown, J. C.; Emslie, A. G.; Hajdas, W.; Holman, G. D.; Hurford, G. J.; Kašparová, J.; Mallik, P. C. V.; Massone, A. M.; McConnell, M. L.; Piana, M.; Prato, M.; Schmahl, E. J.; Suarez-Garcia, E.

    2011-09-01

    X-radiation from energetic electrons is the prime diagnostic of flare-accelerated electrons. The observed X-ray flux (and polarization state) is fundamentally a convolution of the cross-section for the hard X-ray emission process(es) in question with the electron distribution function, which is in turn a function of energy, direction, spatial location and time. To address the problems of particle propagation and acceleration one needs to infer as much information as possible on this electron distribution function, through a deconvolution of this fundamental relationship. This review presents recent progress toward this goal using spectroscopic, imaging and polarization measurements, primarily from the Reuven Ramaty High Energy Solar Spectroscopic Imager ( RHESSI). Previous conclusions regarding the energy, angular (pitch angle) and spatial distributions of energetic electrons in solar flares are critically reviewed. We discuss the role and the observational evidence of several radiation processes: free-free electron-ion, free-free electron-electron, free-bound electron-ion, photoelectric absorption and Compton backscatter (albedo), using both spectroscopic and imaging techniques. This unprecedented quality of data allows for the first time inference of the angular distributions of the X-ray-emitting electrons and improved model-independent inference of electron energy spectra and emission measures of thermal plasma. Moreover, imaging spectroscopy has revealed hitherto unknown details of solar flare morphology and detailed spectroscopy of coronal, footpoint and extended sources in flaring regions. Additional attempts to measure hard X-ray polarization were not sufficient to put constraints on the degree of anisotropy of electrons, but point to the importance of obtaining good quality polarization data in the future.

  1. Hard X-ray telescope using formation flight

    Science.gov (United States)

    Tsunemi, Hiroshi

    2012-07-01

    We are planning to have a hard X-ray telescope using a formation flight (FF) that will cover a large sky area (FFAST: formation flight astronomical survey telescope). In particular, it will focus on the energy range above 10 keV. It consists of two small satellites that will go in FF. One is an X-ray telescope satellite and the other is a detector satellite. Two satellites will be simultaneously launched by a single rocket vehicle into a low earth orbit. They are in FF with a separation of 20m +- 10cm. Two satellites are put into a "relatively circular orbit" so that they are in FF in individual Keplerian orbit. Therefore, we only need a small thruster to compensate the perturbation, which is a quite different point from those employed FF in the past projects (XEUS and SimbolX). Since we can not point to the fixed direction, we will survey the sky. The X-ray telescope satellite carries one super-mirror covering the energy range up to 80 keV. The telescope is 45-cm diameter and its focal length is 20 m. The telescope is a super mirror that has a multi-layer coating covering the energy range up to 80 keV. The detector satellite carries an SDCCD system. The SDCCD is a CCD with a scintillator that is directly attached to the CCD. The CCD chip is fully depleted which can be a back-illuminated CCD. This project, FFAST, will scan a large sky area at hard X-ray region.

  2. Powerful jets from black hole X-ray binaries in Low/Hard X-ray states

    OpenAIRE

    Fender, R. P.

    2000-01-01

    Four persistent (Cygnus X-1, GX 339-4, GRS 1758-258 and 1E 1740.7-2942) and three transient (GS 2023+38, GRO J0422+32 and GS 1354-64) black hole X-ray binary systems have been extensively observed at radio wavelengths during extended periods in the Low/Hard X-ray state, which is characterised in X-rays by a hard power-law spectrum and strong variability. All seven systems show a persistent flat or inverted (in the sense that spectral index alpha >= 0) radio spectrum in this state, markedly di...

  3. Hard-X-ray Zone Plates: Recent Progress

    Directory of Open Access Journals (Sweden)

    Syue-Ren Wu

    2012-09-01

    Full Text Available The technology to focus hard-X-rays (photon energy larger than 1–2 keV has made great progress in the past three years. The progress was particularly spectacular for lenses based on the Fresnel zone plate concept. The spatial resolution notably increased by a factor of three, opening up entirely new domains of application, specifically in biomedical research. As we shall see, this evolution is the result of a painstaking optimization of many different aspects rather than of a single technical breakthrough.

  4. NuSTAR Hard X-ray Optics

    DEFF Research Database (Denmark)

    Koglin, Jason E.; Christensen, Finn Erland; Craig, William W.;

    2005-01-01

    The Nuclear Spectroscopic Telescope Array (NuSTAR) is a small explorer (SMEX) mission currently under an extended Phase A study by NASA. NuSTAR will be the first satellite mission to employ focusing optics in the hard X-ray band (8- 80 keV). Its design eliminates high detector backgrounds, allows...... and production process. We also describe the progress of several components of our independent optics development program that are beginning to reach maturity and could possibly be incorporated into the NuSTAR production scheme. We then present environmental test results that are being conducted in preparation...... of full space qualification of the NuSTAR optics....

  5. Hard-X-Ray-Induced Multistep Ultrafast Dissociation

    Science.gov (United States)

    Travnikova, Oksana; Marchenko, Tatiana; Goldsztejn, Gildas; Jänkälä, Kari; Sisourat, Nicolas; Carniato, Stéphane; Guillemin, Renaud; Journel, Loïc; Céolin, Denis; Püttner, Ralph; Iwayama, Hiroshi; Shigemasa, Eiji; Piancastelli, Maria Novella; Simon, Marc

    2016-05-01

    Creation of deep core holes with very short (τ ≤1 fs ) lifetimes triggers a chain of relaxation events leading to extensive nuclear dynamics on a few-femtosecond time scale. Here we demonstrate a general multistep ultrafast dissociation on an example of HCl following Cl 1 s →σ* excitation. Intermediate states with one or multiple holes in the shallower core electron shells are generated in the course of the decay cascades. The repulsive character and large gradients of the potential energy surfaces of these intermediates enable ultrafast fragmentation after the absorption of a hard x-ray photon.

  6. The Hard X-ray Emission of Cen A

    CERN Document Server

    Beckmann, V; Lubinski, P; Soldi, S; Terrier, R

    2011-01-01

    The radio galaxy Cen A has been detected all the way up to the TeV energy range. This raises the question about the dominant emission mechanisms in the high-energy domain. Spectral analysis allows us to put constraints on the possible emission processes. Here we study the hard X-ray emission as measured by INTEGRAL in the 3-1000 keV energy range, in order to distinguish between a thermal and non-thermal inverse Compton process. The hard X-ray spectrum of Cen A shows a significant cut-off at energies Ec = 434 (+106 -73) keV with an underlying power law of photon index 1.73 +- 0.02. A more physical model of thermal Comptonisation (compPS) gives a plasma temperature of kT = 206+-62 keV within the optically thin corona with Compton parameter y = 0.42 (+0.09 -0.06). The reflection component is significant at the 1.9 sigma level with R = 0.12 (+0.09 -0.10), and a reflection strength R>0.3 can be excluded on a 3 sigma level. Time resolved spectral studies show that the flux, absorption, and spectral slope varied in ...

  7. 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.

  8. Hard X-rays from SN 1993J

    Science.gov (United States)

    Leising, M. D.; Kurfess, J. D.; Clayton, D. D.; Grabelsky, D. A.; Grove, J. E.; Johnson, W. N.; Jung, G. V.; Kinzer, R. L.; Kroeger, R. A.; Purcell, W. R.

    1994-01-01

    The Oriented Scintillation Spectrometer Experiment (OSSE) on the Compton Observatory observed SN 1993J during three intervals centered approximately 12, 30, and 108 days after its outburst. Hard X-ray emission was detected in the first two of these intervals. No emission was seen in the third observation or in two earlier observations in 1991 and 1992. The coincidence of the observed excess with the outburst of SN 1993J and the consistency of the spectra and time evolution with those seen at lower energies by ROSAT and ASCA (Astro-D) argue that the observed emission is indeed from SN 1993J. It is probably due to the interaction of the fast supernova ejecta with circumstellar material. The luminosity, 5 x 10(exp 40) ergs/sec (50-150 keV) in the first interval, is significantly larger than predicted. Extrapolating the spectrum to a few keV accounts for most or all of the observed emission at low energy. The observed high temperature, 10(exp 9) K, is easily obtained in the shocked circumstellar matter, but a surprisingly high density is required there to give the observed luminosity, and little or no additional X-ray emission from denser shocked supernova ejecta is allowed. The hard emission might also be explained in terms of the shocked supernova ejecta itself with unexpectedly high temperature.

  9. The Serendipitous Extragalactic X-Ray Source Identification (SEXSI) Program: I. Characteristics of the Hard X-Ray Sample

    CERN Document Server

    Harrison, F A; Mao, P H; Helfand, D J; Stern, D; Harrison, Fiona A.; Eckart, Megan E.; Mao, Peter H.; Helfand, David J.; Stern, Daniel

    2003-01-01

    The Serendipitous Extragalactic X-ray Source Identification (SEXSI) Program is designed to extend greatly the sample of identified extragalactic hard X-ray 2-10 keV sources at intermediate fluxes ($sim 10^{-13} - 10^{-15} erg/cm2/s$). SEXSI, which studies sources selected from more than 2 deg$^2$, provides an essential complement to the {em Chandra} Deep Fields, which reach depths of $5 times 10^{-16} erg/cm2/s$ (hardrange) but over a total area of $< 0.2$ deg$^2$. In this paper we describe the characteristics of the survey and our X-ray data analysis methodology. We present the cumulative flux distribution for the X-ray sample of 1034 hard sources, and discuss the distribution of spectral hardness ratios. Our lognlogs in this intermediate flux range connects to those found in the deep fields, and by combining the data sets, we constrain the hard X-ray population over the flux range where the differential number counts change slope, and from which the bulk of the 2 -- 10 keV X-ray background arises. We fur...

  10. Correlation between Hard X-ray Peak Flux and Soft X-ray Peak Flux in the Outburst Rise of Low Mass X-ray Binaries

    OpenAIRE

    Yu, Wenfei; van der Klis, Michiel; Fender, Rob

    2004-01-01

    We have analyzed {\\it Rossi} X-ray timing explorer (RXTE) pointed observations of the outbursts of black hole and neutron star soft X-ray transients in which an initial low/hard state or `island' state, followed by a transition to a softer state, was observed. In three sources, the black hole transient XTE J1550-564, the neutron star transient Aquila X-1 and a quasi-persistent neutron star low mass X-ray binary (LMXB) 4U 1705-44, two such outbursts were found. We find that the flux of the sof...

  11. Balloon-Borne, High-Energy Astrophysics: Experiences from the 1960s to the 1980s

    Science.gov (United States)

    Fishman, Gerald J.

    2008-01-01

    Observational high-energy astrophysics in the hard-x-ray and gamma-ray regions owes its development and initial successes to the balloon-borne development of detector systems, as well as pioneering observations, primarily in the timeframe from the 1960s to the 1990s. I will describe some of the first observations made by the Rice University balloon group in the 1960s, including the impetus for these observations. The appearance of SN 1987a led to several balloon-flight campaigns, sponsored by NASA, from Alice Springs, Australia in 1987 and 1988. During the 1980s, prototypes of instruments for the Compton Gamma Ray Observatory were flown on many balloon flights, which greatly enhanced the success of that mission.

  12. Backscatter of hard X-rays in the solar atmosphere. [Calculating the reflectance of solar x ray emission

    Science.gov (United States)

    Bai, T.; Ramaty, R.

    1977-01-01

    The solar photosphere backscatters a substantial fraction of the hard X rays from solar flares incident upon it. This reflection was studied using a Monte Carlo simulation which takes into account Compton scattering and photo-electric absorption. Both isotropic and anisotropic X ray sources are considered. The bremsstrahlung from an anisotropic distribution of electrons are evaluated. By taking the reflection into account, the inconsistency is removed between recent observational data regarding the center-to-limb variation of solar X ray emission and the predictions of models in which accelerated electrons are moving down toward the photosphere.

  13. Nature of Hard X-ray Source from Optical Identification of the ASCA Large Sky Survey

    OpenAIRE

    Akiyama, M.; Ohta, K.; Yamada, T.; Ueda, Y.; Takahashi, T.; M. SAKANO; Tsuru, T.; Lehmann, I.; G. Hasinger(JHU)

    1998-01-01

    We present results of optical identification of the ASCA Large Sky Survey. X-ray sources which have hard X-ray spectra were identified with type-2 AGN at redshifts smaller than 0.5. It is supported that the absorbed X-ray spectrum of type-2 AGN makes the Cosmic X-ray Background harder in the hard X-ray band than type-1 AGN, which is main contributer in the soft X-ray band. Absence of type-2 AGN at redshift larger than 1 in the identified sample, which contrasts to the existence of 6 broad-lin...

  14. Small pixel CZT detector for hard X-ray spectroscopy

    Science.gov (United States)

    Wilson, Matthew David; Cernik, Robert; Chen, Henry; Hansson, Conny; Iniewski, Kris; Jones, Lawrence L.; Seller, Paul; Veale, Matthew C.

    2011-10-01

    A new small pixel cadmium zinc telluride (CZT) detector has been developed for hard X-ray spectroscopy. The X-ray performance of four detectors is presented and the detectors are analysed in terms of the energy resolution of each pixel. The detectors were made from CZT crystals grown by the travelling heater method (THM) bonded to a 20×20 application specific integrated circuit (ASIC) and data acquisition (DAQ) system. The detectors had an array of 20×20 pixels on a 250 μm pitch, with each pixel gold-stud bonded to an energy resolving circuit in the ASIC. The DAQ system digitised the ASIC output with 14 bit resolution, performing offset corrections and data storage to disc in real time at up to 40,000 frames per second. The detector geometry and ASIC design was optimised for X-ray spectroscopy up to 150 keV and made use of the small pixel effect to preferentially measure the electron signal. A 241Am source was used to measure the spectroscopic performance and uniformity of the detectors. The average energy resolution (FWHM at 59.54 keV) of each pixel ranged from 1.09±0.46 to 1.50±0.57 keV across the four detectors. The detectors showed good spectral performance and uniform response over almost all pixels in the 20×20 array. A large area 80×80 pixel detector will be built that will utilise the scalable design of the ASIC and the large areas of monolithic spectroscopic grade THM grown CZT that are now available. The large area detector will have the same performance as that demonstrated here.

  15. NuSTAR Hard X-ray Survey of the Galactic Center Region II: X-ray Point Sources

    CERN Document Server

    Hong, JaeSub; Hailey, Charles J; Nynka, Melania; Zhang, Shuo; Gotthelf, Eric; Fornasini, Francesca M; Krivonos, Roman; Bauer, Franz; Perez, Kerstin; Tomsick, John A; Bodaghee, Arash; Chiu, Jeng-Lun; Clavel, Maïca; Stern, Daniel; Grindlay, Jonathan E; Alexander, David M; Aramaki, Tsuguo; Baganoff, Frederick K; Barret, David; Barrière, Nicolas; Boggs, Steven E; Canipe, Alicia M; Christensen, Finn E; Craig, William W; Desai, Meera A; Forster, Karl; Giommi, Paolo; Grefenstette, Brian W; Harrison, Fiona A; Hong, Dooran; Hornstrup, Allan; Kitaguchi, Takao; Koglin, Jason E; Madsen, Kristen K; Mao, Peter H; Miyasaka, Hiromasa; Perri, Matteo; Pivovaroff, Michael J; Puccetti, Simonetta; Rana, Vikram; Westergaard, Niels J; Zhang, William W; Zoglauer, Andreas

    2016-01-01

    We present the first survey results of hard X-ray point sources in the Galactic Center (GC) region by NuSTAR. We have discovered 70 hard (3-79 keV) X-ray point sources in a 0.6 deg^2 region around Sgr A* with a total exposure of 1.7 Ms, and 7 sources in the Sgr B2 field with 300 ks. We identify clear Chandra counterparts for 58 NuSTAR sources and assign candidate counterparts for the remaining 19. The NuSTAR survey reaches X-ray luminosities of ~4 x and ~8 x 10^32 erg s^-1 at the GC (8 kpc) in the 3-10 and 10-40 keV bands, respectively. The source list includes three persistent luminous X-ray binaries and the likely run-away pulsar called the Cannonball. New source-detection significance maps reveal a cluster of hard (>10 keV) X-ray sources near the Sgr A diffuse complex with no clear soft X-ray counterparts. The severe extinction observed in the Chandra spectra indicates that all the NuSTAR sources are in the central bulge or are of extragalactic origin. Spectral analysis of relatively bright NuSTAR sources ...

  16. Exploring hard X-ray polarimetry with Astrosat-CZTI

    Science.gov (United States)

    Vadawale, Santosh

    2016-07-01

    The CZT Imager instrument onboard recently launched Astrosat is a hard X-ray telescope capable of spectroscopy and imaging in the energy range of 20 - 150 keV using the technique of coded mask imaging. It consists of a large array of pixilated CZT detector modules as the detector plane having total geometric area of 976 cm^{2} and thickness of 5 mm. Since the detectors have significant detection efficiency beyond the primary energy range of CZTI, it can also be used for spectroscopy as well as polarization measurement in the extended energy range of 150 - 300 keV by identifying the Compton scattering events in the adjacent pixels. The polarimetric capability of Astrosat-CZTI using the Compton events has been investigated in detail by means of Geant4 simulations and has been experimentally demonstrated during the ground testing of CZTI. The pertinence of Compton events in the CZTI detector plane for astrophysical observation has demonstrated during the early observation with the detection of multiple GRBs in the Compton events. One GRB detected by CZTI show presence of azimuthal modulation suggesting highly polarized nature of the X-ray emission. The initial Crab observations also indicate presence of azimuthal modulation. Here we present preliminary analysis of the Compton events in the multiple observations carried out during the initial performance verification phase of Astrosat CZTI.

  17. Hard x-ray single crystal bi-mirror.

    Science.gov (United States)

    Lyubomirskiy, M; Snigireva, I; Kuznetsov, S; Yunkin, V; Snigirev, A

    2015-05-15

    We report a novel hard x-ray interferometer consisting of two parallel channels manufactured in a single Si crystal by means of microfabrication technology. The sidewall surfaces of the channels, similar to mirrors, scatter at very small incident angles, acting equivalently to narrow micrometer size slits as in the Young double-slit interferometer. Experimental tests of the interferometer were performed at the ESRF ID06 beamline in the energy range from 12 to 16 keV. The interference patterns at different grazing incidence angles were recorded in the near- and far-field. Evaluation of the influence of the channel surface roughness on the visibility of interference fringes was performed. The proposed interferometer design allows the arrangement of mirrors at different split distances.

  18. ISO investigates the nature of extremely-red hard X-ray sources responsible for the X-ray background

    CERN Document Server

    Franceschini, A; Césarsky, C J; Elbaz, D; Flores, H; Granato, G L; Franceschini, Alberto; Fadda, Dario; Cesarsky, Catherine; Elbaz, David; Flores, Hector; Granato, Gian Luigi

    2001-01-01

    We analyse very deep X-ray and mid-IR surveys in common areas of the Lockman Hole and the HDF North to study the sources of the X-ray background (XRB) and to test the standard obscured accretion paradigm. We detect with ISO a rich population of X-ray luminous sources with red optical colours, including a fraction identified with Extremely Red Objects (R-K > 5) and galaxies with SEDs typical of normal massive ellipticals or spirals at z ~ 1. The high 0.5-10 keV X-ray luminosities of these objects (1E43-1E45 erg/s) indicate that the ultimate energy source is gravitational accretion, while the X-ray to IR flux ratios and the X-ray spectral hardness show evidence of photoelectric absorption at low X-ray energies. An important hint on the physics comes from the mid-IR data at 6.7 and 15 um, well reproduced by model spectra of completely obscured quasars under standard assumptions and l.o.s. optical depths tau ~ 30-40. Other predictions of the standard XRB picture, like the distributions of intrinsic bolometric lum...

  19. Spectral Variability in Hard X-rays and the Evidence for a 13.5 Years Period in the Bright Quasar 3C273

    Indian Academy of Sciences (India)

    R. K. Manchanda

    2002-09-01

    We report the observation of nearest quasar 3C273 made with LASE instrument on November 20th, 1998 as a part of our continuing programme of balloon borne hard X-ray observations in the 20–200 keV band using high sensitivity Large Area Scintillation counter Experiment. Our data clearly show a steep spectrum in the 20–200 keV with power law spectral index = 226 ± 0.07. This is in complete contrast to the reported data from OSSE and BeppoSAX which suggest the value of 1.3 to 1.6 for the power law index in the X-ray energy band, but is quite consistent with the value derived for the high energy gamma ray data. A single power law fit in the X-ray and gamma ray energy bands points to a common origin of these photons and the absence of spectral break around 1 MeV as suggested in literature. We have reanalyzed the available data to study the temporal variability of the spectrum in the hard X-ray band. Our analysis reveals that 50 keV flux from the source, shows a strong modulation with a period of about 13.5 years. The analysis of the optical light curve of the source also supports the 5000 day period.We discuss the emission mechanism and the possible sites for X-ray photons along with the implications of the long term periodicity with respect to source geometry.

  20. Femtosecond X-ray Absorption Spectroscopy at a Hard X-ray Free Electron Laser

    DEFF Research Database (Denmark)

    Lemke, Henrik T.; Bressler, Christian; Chen, Lin X.;

    2013-01-01

    X-ray free electron lasers (XFELs) deliver short (time-resolved studies. Here we show that, despite the inherent instabilities of current (SASE based) XFELs, they can be used for measuring high......-quality X-ray absorption data and we report femtosecond time-resolved X-ray absorption near-edge spectroscopy (XANES) measurements of a spin-crossover system, iron(II) tris(2,2'-bipyridine) in water. The data indicate that the low-spin to high-spin transition can be modeled by single-exponential kinetics...

  1. Observational Aspects of Hard X-ray Polarimetry

    OpenAIRE

    Chattopadhyay, Tanmoy; Vadawale, Santosh

    2016-01-01

    Sensitive polarization measurements in X-ray may address a wealth of astrophysical phenomena, which so far remain beyond our understanding through available X-ray spectroscopic, imaging, and timing studies. Though scientific potential of X-ray polarimetry was realized long ago, there has not been any significant advancement in this field for the last four decades since the birth of X-ray astronomy. The only successful polarization measurement in X-rays dates ...

  2. High Energy Replicated Optics to Explore the Sun Balloon-Borne Telescope: Astrophysical Pointing

    Science.gov (United States)

    Gaskin, Jessica; Wilson-Hodge, Colleen; Ramsey, Brian; Apple, Jeff; Kurt, Dietz; Tennant, Allyn; Swartz, Douglas; Christe, Steven D.; Shih, Albert

    2014-01-01

    On September 21, 2013, the High Energy Replicated Optics to Explore the Sun, or HEROES, balloon-borne x-ray telescope launched from the Columbia Scientific Balloon Facility's site in Ft. Summer, NM. The flight lasted for approximately 27 hours and the observational targets included the Sun and astrophysical sources GRS 1915+105 and the Crab Nebula. Over the past year, the HEROES team upgraded the existing High Energy Replicated Optics (HERO) balloon-borne telescope to make unique scientific measurements of the Sun and astrophysical targets during the same flight. The HEROES Project is a multi-NASA Center effort with team members at both Marshall Space Flight Center (MSFC) and Goddard Space Flight Center (GSFC), and is led by Co-PIs (one at each Center). The HEROES payload consists of the hard X-ray telescope HERO, developed at MSFC, combined with several new systems. To allow the HEROES telescope to make observations of the Sun, a new solar aspect system was added to supplement the existing star camera for fine pointing during both the day and night. A mechanical shutter was added to the star camera to protect it during solar observations and two alignment monitoring systems were added for improved pointing and post-flight data reconstruction. This mission was funded by the NASA HOPE (Hands-On Project Experience) Training Opportunity awarded by the NASA Academy of Program/Project and Engineering Leadership, in partnership with NASA's Science Mission Directorate, Office of the Chief Engineer and Office of the Chief Technologist.

  3. Observation constraints of the hard X-ray modulation telescope HXMT

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The hard X-ray modulation telescope HXMT is a low orbit X-ray space telescope whose main science goals are to accomplish a hard X-ray all sky survey and to study timing and spectral characteristics of X-ray sources.HXMT has three kinds of science instruments:the high energy X-ray detector(HE),the medium energy X-ray detector(ME) and the low energy X-ray detector(LE).The observation schedule of HXMT is a key to achieving the science goal of HXMT,and the analysis of the observation constraints is one of the first tasks in making the observation schedule.This paper analyzes how the observation constraints influence the sky visibility and the visible time distribution of X-ray sources and discusses the schedule strategy with regard to the observation constraints.

  4. On the Spectral Slopes of Hard X-ray Emission from Black Hole Candidates

    OpenAIRE

    Ebisawa, Ken; Titarchuk, Lev G.; Chakrabarti, Sandip K.

    1995-01-01

    Most black hole candidates exhibit characteristic power-law like hard X-ray emission above $\\sim$ 10 keV. In the {\\em high state}, in which 2 -- 10 keV luminosity is relatively high, the energy index of the hard X-ray emission is usually greater than 1 --- typically $\\sim 1.5$. On the other hand, in the {\\em low state}, the hard X-ray energy index is 0.3 -- 0.9. In this paper, we suggest that this difference of the hard X-ray spectral slopes may be due to two different Comptonization mechanis...

  5. The origin of the hard X-ray tail in neutron-star X-ray binaries

    Science.gov (United States)

    Reig, P.; Kylafis, N.

    2016-06-01

    Context. Neutron star X-ray binaries emit a compact, optically thick, relativistic radio jet during low-luminosity, usually hard states, as Galactic black-hole X-ray binaries do. When radio emission is bright, a hard power-law tail without evidence for an exponential cutoff is observed in most systems. Aims: We have developed a jet model that explains many spectral and timing properties of black-hole binaries in the states where a jet is present. Our goal is to investigate whether our jet model can reproduce the hard tail, with the correct range of photon index and the absence of a high-energy cutoff, in neutron-star X-ray binaries. Methods: We performed Monte Carlo simulations of the Compton upscattering of soft, accretion-disk or boundary layer photons in the jet and computed the emergent energy spectra, as well as the time lag of hard photons with respect to softer ones as a function of Fourier frequency. We fit the energy spectra with a power law modified by an exponential cutoff at high energy. Results: We demonstrate that our jet model naturally explains the observed power-law distribution with photon index in the range 1.8-3. With an appropriate choice of the parameters, the cutoff expected from Comptonization is shifted to energies above ~300 keV, producing a pure power law without any evidence for a rollover, in agreement with the observations. Conclusions: Our results reinforce the idea that the link between the outflow (jet) and inflow (disk) in X-ray binaries does not depend on the nature of the compact object, but on the process of accretion. Furthermore, we address the differences between jets in black-hole and neutron-star X-ray binaries and predict that the break frequency in the spectral energy distribution of neutron-star X-ray binaries, as a class, will be lower than that of black-hole binaries.

  6. Fourier-transform Ghost Imaging with Hard X-rays

    OpenAIRE

    Hong YU; Lu, Ronghua; Han, Shensheng; Xie, Honglan; Du, Guohao; Xiao, Tiqiao; Zhu, Daming

    2016-01-01

    Knowledge gained through X-ray crystallography fostered structural determination of materials and greatly facilitated the development of modern science and technology in the past century. Atomic details of sample structures is achievable by X-ray crystallography, however, it is only applied to crystalline structures. Imaging techniques based on X-ray coherent diffraction or zone plates are capable of resolving the internal structure of non-crystalline materials at nanoscales, but it is still ...

  7. Progress on multi-order hard x-ray imaging with multilayer zone plates

    Science.gov (United States)

    Osterhoff, Markus; Döring, Florian; Eberl, Christian; Wilke, Robin; Wallentin, Jesper; Krebs, Hans-Ulrich; Sprung, Michael; Salditt, Tim

    2015-09-01

    Hard x-ray focusing and imaging on the few nano metre scale has gained a lot of attraction in the last couple of years. Thanks to new developments in fabrication and inspection of high-N.A. optics, focusing of hard x-rays has caught up with the focusing performance for soft x-rays. Here we review the latest imaging experiments of the Göttinger Multilayer zone plate collaboration, summarising our route from 1D to 2D lenses for different hard x-ray energies, and recapitulate recent progress on a journey from focusing to imaging.

  8. Hard X-ray Detector (HXD) on Board Suzaku

    CERN Document Server

    Takahashi, T; Endo, M; Endo, Y; Ezoe, Y; Fukazawa, Y; Hamaya, M; Hirakuri, S; Hong, S; Horii, M; Inoue, H; Isobe, N; Itoh, T; Iyomoto, N; Kamae, T; Kasama, D; Kataoka, J; Kato, H; Kawaharada, M; Kawano, N; Kawashima, K; Kawasoe, S; Kishishita, T; Kitaguchi, T; Kobayashi, Y; Kokubun, M; Kotoku, J; Kouda, M; Kubota, A; Kuroda, Y; Madejski, G; Makishima, K; Masukawa, K; Matsumoto, Y; Mitani, T; Miyawaki, R; Mizuno, T; Mori, K; Mori, M; Murashima, M; Murakami, T; Nakazawa, K; Niko, H; Nomachi, M; Okada, Y; Ohno, M; Oonuki, K; Ota, N; Ozawa, H; Sato, G; Shinoda, S; Sugiho, M; Suzuki, M; Taguchi, K; Takahashi, H; Takahashi, I; Takeda, S; Tamura, K; Tamura, T; Tanaka, T; Tanihata, C; Tashiro, M; Terada, Y; Tominaga, S; Uchiyama, Y; Watanabe, S; Yamaoka, K; Yanagida, T; Yonetoku, D

    2006-01-01

    The Hard X-ray Detector (HXD) on board Suzaku covers a wide energy range from 10 keV to 600 keV by combination of silicon PIN diodes and GSO scintillators. The HXD is designed to achieve an extremely low in-orbit back ground based on a combination of new techniques, including the concept of well-type active shield counter. With an effective area of 142 cm^2 at 20 keV and 273 cm2 at 150 keV, the background level at the sea level reached ~1x10^{-5} cts s^{-1} cm^{-2} keV^{-1} at 30 keV for the PI N diodes, and ~2x10^{-5} cts s^{-1} cm^{-2} keV^{-1} at 100 keV, and ~7x10^{-6} cts s^{-1} cm^{-2} keV^{-1} at 200 keV for the phoswich counter. Tight active shielding of the HXD results in a large array of guard counters surrounding the main detector parts. These anti-coincidence counters, made of ~4 cm thick BGO crystals, have a large effective area for sub-MeV to MeV gamma-rays. They work as an excellent gamma-ray burst monitor with limited angular resolution (~5 degree). The on-board signal-processing system and th...

  9. Hard X-ray and radio observations of Abell 754

    CERN Document Server

    Fusco-Femiano, R; Grandi, S D; Molendi, S; Feretti, L; Giovannini, G; Bacchi, M; Govoni, F

    2003-01-01

    We present a long BeppoSAX observation of Abell 754 that reports a nonthermal excess with respect to the thermal emission at energies greater than ~45 keV. A VLA radio observation at 1.4 GHz definitely confirms the existence of diffuse radio emission in the central region of the cluster, previously suggested by images at 74 and 330 MHz (Kassim et al 2001), and reports additional features. Besides, our observation determines a steeper radio halo spectrum in the 330-1400 MHz frequency range with respect to the spectrum detected at lower frequencies, indicating the presence of a spectral cutoff. The presence of a radio halo in A754, considered the prototype of a merging cluster, reinforces the link between formation of Mpc-scale radio regions and very recent or current merger processes. The radio results combined with the hard X-ray excess detected by BeppoSAX give information on the origin of the electron population responsible for nonthermal phenomena in galaxy clusters. We discuss also the possibility that 26...

  10. Quantitative phase imaging using hard x-rays

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, K.A.; Paganin, D.; Barnea, Z. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Cookson, D. F. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Gureyev, T.E. [Melbourne Univ., Parkville, VIC (Australia). School of Physics]|[CSIRO, Clayton, VIC (Australia). Div. of Forestry and Forest Products

    1997-06-01

    The quantitative imaging of a phase object using 16 keV x-rays is reported. The theoretical basis of the techniques is presented along with its implementation using a synchrotron x-ray source. It is found that the phase image is in quantitative agreement with independent measurements of the object. 13 refs., 5 figs.

  11. In-Line Phase-Contrast Imaging Using Partially Coherent Hard X-Ray

    Institute of Scientific and Technical Information of China (English)

    喻虹; 朱频频; 韩申生; 罗震林; 高琛

    2003-01-01

    An experimental study of in-line hard x-ray phase-contrast imaging had been performed, using the polychromatic output of an x-ray tube. The results are in good agreement with partially coherent theory of hard x-ray phasecontrast imaging. The new technique provides the advantage to obtain the radiographs of large samples in an acceptable exposure time, which is very important to clinical applications.

  12. NuSTAR Hard X-ray Survey of the Galactic Center Region I: Hard X-ray Morphology and Spectroscopy of the Diffuse Emission

    CERN Document Server

    Mori, Kaya; Krivonos, Roman; Hong, Jaesub; Ponti, Gabriele; Bauer, Franz; Perez, Kerstin; Nynka, Melania; Zhang, Shuo; Tomsick, John A; Alexander, David M; Baganoff, Frederick K; Barret, Didier; Barriere, Nicolas; Boggs, Steven E; Canipe, Alicia M; Christensen, Finn E; Craig, William W; Forster, Karl; Giommi, Paolo; Grefenstette, Brian W; Grindlay, Jonathan E; Harrison, Fiona A; Hornstrup, Allan; Kitaguchi, Takao; Koglin, Jason E; Luu, Vy; Madsen, Kristen K; Mao, Peter H; Miyasaka, Hiromasa; Perri, Matteo; Pivovaroff, Michael J; Puccetti, Simonetta; Rana, Vikram; Stern, Daniel; Westergaard, Niels J; Zhang, William W; Zoglauer, Andreas

    2015-01-01

    We present the first sub-arcminute images of the Galactic Center above 10 keV, obtained with NuSTAR. NuSTAR resolves the hard X-ray source IGR J17456-2901 into non-thermal X-ray filaments, molecular clouds, point sources and a previously unknown central component of hard X-ray emission (CHXE). NuSTAR detects four non-thermal X-ray filaments, extending the detection of their power-law spectra with $\\Gamma\\sim1.3$-$2.3$ up to ~50 keV. A morphological and spectral study of the filaments suggests that their origin may be heterogeneous, where previous studies suggested a common origin in young pulsar wind nebulae (PWNe). NuSTAR detects non-thermal X-ray continuum emission spatially correlated with the 6.4 keV Fe K$\\alpha$ fluorescence line emission associated with two Sgr A molecular clouds: MC1 and the Bridge. Broad-band X-ray spectral analysis with a Monte-Carlo based X-ray reflection model self-consistently determined their intrinsic column density ($\\sim10^{23}$ cm$^{-2}$), primary X-ray spectra (power-laws wi...

  13. Multilayer on-chip stacked Fresnel zone plates: Hard x-ray fabrication and soft x-ray simulations

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kenan; Wojcik, Michael J.; Ocola, Leonidas E.; Divan, Ralu; Jacobsen, Chris

    2015-11-01

    Fresnel zone plates are widely used as x-ray nanofocusing optics. To achieve high spatial resolution combined with good focusing efficiency, high aspect ratio nanolithography is required, and one way to achieve that is through multiple e-beam lithography writing steps to achieve on-chip stacking. A two-step writing process producing 50 nm finest zone width at a zone thickness of 1.14 µm for possible hard x-ray applications is shown here. The authors also consider in simulations the case of soft x-ray focusing where the zone thickness might exceed the depth of focus. In this case, the authors compare on-chip stacking with, and without, adjustment of zone positions and show that the offset zones lead to improved focusing efficiency. The simulations were carried out using a multislice propagation method employing Hankel transforms.

  14. Fabrication of 200 nm Period Hard X-ray Phase Gratings

    OpenAIRE

    Miao, Houxun; Gomella, Andrew A.; Chedid, Nicholas; Chen, Lei; Wen, Han

    2014-01-01

    Far field X-ray grating interferometry achieves extraordinary phase sensitivity in imaging weakly absorbing samples, provided that the grating period is within the transverse coherence length of the X-ray source. Here we describe a cost-efficient process to fabricate large area, 100 nm half-pitch hard X-ray phase gratings with an aspect ratio of 32. The nanometric gratings are suitable for ordinary compact X-ray sources having low spatial coherence, as demonstrated by X-ray diffraction experi...

  15. Hard x-ray spectrometers for NIF (abstract)

    Science.gov (United States)

    Seely, John; Holland, Glenn; Brown, Charles; Deslattes, Richard; Hudson, Lawrence; Bell, Perry; Miller, Michael; Back, Christina

    2001-01-01

    A National Ignition Facility (NIF) core diagnostic instrument has been designed and will be fabricated to record x-ray spectra in the 1.2-20 keV energy range. The high-energy electronic x-ray instrument has four reflection crystals with overlapping coverage of 1.2-10.9 keV and one transmission crystal covering 8.6-20 keV. The spectral resolving power varies from approximately 1000 at low energies to 315 at 20 keV. The spectrum produced by each crystal is recorded by a modified commercial dental x-ray charge coupled device (CCD) detector. The scintillators on the CCD detectors are optimized for the energy ranges. A one-channel x-ray spectrometer, using one transmission crystal covering 12-60 keV, will be fabricated for the OMEGA laser facility. The transmission crystal spectrometers are based on instruments originally designed at National Institute for Standards and Technology for the purpose of characterizing the x-ray flux from medical radiography sources. Utilizing one of those instruments and a commercial dental x-ray CCD detector, x-ray images were recorded using a single pulse from a laboratory x-ray source with a peak charging voltage of 200 kV. A resolving power of 300 was demonstrated by recording on film the Kα1 and Kα2 characteristic x-ray lines near 17 keV from a molybdenum anode. The continuum radiation from a tungsten anode was recorded in the 20-50 keV energy range. The transmission crystal spectrometer has sufficient spectral resolution and sensitivity to record the line and continuum radiation from high-Z targets irradiated by the NIF laser and the OMEGA laser.

  16. Weak Hard X-Ray Emission from Broad Absorption Line Quasars: Evidence for Intrinsic X-Ray Weakness

    DEFF Research Database (Denmark)

    Luo, B.; Brandt, W. N.; Alexander, D. M.;

    2014-01-01

    We report NuSTAR observations of a sample of six X-ray weak broad absorption line (BAL) quasars. These targets, at z = 0.148-1.223, are among the optically brightest and most luminous BAL quasars known at z 330 times weaker than...... are not detected. The hard X-ray (8-24 keV) weakness observed by NuSTAR requires Compton-thick absorption if these objects have nominal underlying X-ray emission. However, a soft stacked effective photon index (Γeff ≈ 1.8) for this sample disfavors Compton-thick absorption in general. The uniform hard X...... expected for typical quasars. Our results from a pilot NuSTAR study of two low-redshift BAL quasars, a Chandra stacking analysis of a sample of high-redshift BAL quasars, and a NuSTAR spectral analysis of the local BAL quasar Mrk 231 have already suggested the existence of intrinsically X-ray weak BAL...

  17. Weak hard X-ray emission from two broad absorption line quasars observed with NuSTAR: Compton-thick absorption or intrinsic X-ray weakness?

    DEFF Research Database (Denmark)

    Luo, B.; Brandt, W. N.; Alexander, D. M.;

    2013-01-01

    We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus...

  18. On the origin of the hard X-ray tail in neutron-star X-ray binaries

    CERN Document Server

    Reig, P

    2016-01-01

    Neutron star X-ray binaries emit a compact, optically thick, relativistic radio jet during low-luminosity, usually hard states, as Galactic black-hole X-ray binaries do. When radio emission is bright, a hard power-law tail without evidence for an exponential cutoff is observed in most systems. We have developed a jet model that explains many spectral and timing properties of black-hole binaries in the states where a jet is present. Our goal is to investigate whether our jet model can reproduce the hard tail, with the correct range of photon index and the absence of a high-energy cutoff, in neutron-star X-ray binaries. We have performed Monte Carlo simulations of the Compton upscattering of soft, accretion-disk or boundary layer photons, in the jet and computed the emergent energy spectra, as well as the time lag of hard photons with respect to softer ones as a function of Fourier frequency. We demonstrate that our jet model explains the observed power-law distribution with photon index in the range 1.8-3. Wit...

  19. Hard X-ray photoelectron spectroscopy: A few recent applications

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, M., E-mail: mtaguchi@spring8.or.jp [RIKEN SPring-8 Center, Sayo, Hyogo 679-5148 (Japan); Takata, Y.; Chainani, A. [RIKEN SPring-8 Center, Sayo, Hyogo 679-5148 (Japan)

    2013-10-15

    Highlights: ► We discuss recent applications of HAXPES carried out at BL29XU in SPring-8. ► We provide a brief description of the salient features of the instrument. ► The recoil effect of photoelectrons in core levels and valence band are discussed. ► We overview HAXPES studies of a series of 3d transition metal compounds. ► The extended cluster model for explaining well-screened feature is presented. -- Abstract: In this report, we discuss a few recent applications of hard X-ray photoelectron spectroscopy (HAXPES) carried out at the RIKEN beamline BL29XU in SPring-8. We first provide a brief description of the salient features of the instrument in operation at BL29 XU in SPring-8. HAXPES studies on the recoil effect of photoelectrons in core levels and valence band states are presented. The experiments show remarkable consistency with theoretical results and indicate the role of phonon excitations in the recoil effect of photoelectrons. We then overview HAXPES applied to the study of a series of 3d transition metal (TM) compounds. The HAXPES experimental results often show an additional well-screened feature in bulk sensitive electronic structure of strongly correlated compounds compared to surface sensitive spectra. The extended cluster model developed by us for explaining this well-screened feature is validated for a series of TM compounds. These results show that HAXPES is a valuable tool for the study of doping and temperature dependent electronic structure of solids with tremendous potential for future activities.

  20. Solar hard X-ray halo from decaying neutrons

    OpenAIRE

    MacKinnon, A. L.

    2007-01-01

    Aims: To quantify the solar X-ray halo resulting from inner bremsstrahlung in beta decay of neutrons generated by cosmic ray bombardment of the solar surface. Methods: We show analytically how the angular form of this X-ray halo directly reflects the energy distribution of neutrons escaping the Sun. Previous Monte Carlo calculations of solar albedo neutron production are used to normalise an assumed parametric form for the escaping neutron distribution and thus to estimate the halo's inte...

  1. Design and tests of the hard X-ray polarimeter X-Calibur

    Energy Technology Data Exchange (ETDEWEB)

    Beilicke, M., E-mail: beilicke@physics.wustl.edu [Washington University, St. Louis, MO (United States); Baring, M.G. [Rice University, TX (United States); Barthelmy, S. [Goddard Space Flight Center, MD (United States); Binns, W.R.; Buckley, J.; Cowsik, R.; Dowkontt, P.; Garson, A.; Guo, Q. [Washington University, St. Louis, MO (United States); Haba, Y. [Nagoya University (Japan); Israel, M.H. [Washington University, St. Louis, MO (United States); Kunieda, H. [Nagoya University (Japan); Lee, K. [Washington University, St. Louis, MO (United States); Matsumoto, H.; Miyazawa, T. [Nagoya University (Japan); Okajima, T.; Schnittman, J. [Goddard Space Flight Center, MD (United States); Tamura, K. [Nagoya University (Japan); Tueller, J. [Goddard Space Flight Center, MD (United States); Krawczynski, H. [Washington University, St. Louis, MO (United States)

    2012-11-11

    X-ray polarimetry will give qualitatively new information about high-energy astrophysical sources. We designed, built and tested a hard X-ray polarimeter X-Calibur to be used in the focal plane of the InFOC{mu}S grazing incidence hard X-ray telescope. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 10-80 keV X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity.

  2. Extended hard-X-ray emission in the inner few parsecs of the Galaxy

    DEFF Research Database (Denmark)

    Perez, Kerstin; Hailey, Charles J.; Bauer, Franz E.;

    2015-01-01

    of objects emitting soft X-rays (less than 10 kiloelectronvolts) within the surrounding hundreds of parsecs, as well as the population responsible for unresolved X-ray emission extending along the Galactic plane, is dominated by accreting white dwarf systems. Observations of diffuse hard-X-ray (more......-40 kiloelectronvolt range. This emission is more sharply peaked towards the Galactic Centre than is the surface brightness of the soft-X-ray population. This could indicate a significantly more massive population of accreting white dwarfs, large populations of low-mass X-ray binaries or millisecond pulsars, or...... than 10 kiloelectronvolts) emission in the inner 10 parsecs, however, have been hampered by the limited spatial resolution of previous instruments. Here we report the presence of a distinct hard-X-ray component within the central 4 × 8 parsecs, as revealed by subarcminute-resolution images in the 20...

  3. The High Energy X-ray Imager Technology (HEXITEC) for Solar Hard X-ray Observations

    Science.gov (United States)

    Christe, Steven; Shih, Albert Y.; Gaskin, Jessica; Wilson-Hodge, Colleen; Seller, Paul; Wilson, Matthew

    2015-04-01

    High angular resolution HXR optics require detectors with a large number of fine pixels in order to adequately sample the telescope point spread function (PSF) over the entire field of view. Excessively over-sampling the PSF will increase readout noise and require more processing with no appreciable increase in image quality. An appropriate level of over-sampling is to have 3 pixels within the HPD. For current high resolution X-ray mirrors, the HPD is about 25 arcsec. Over a 6-m focal length this converts to 750 µm, the optimum pixel size is around 250 µm. Annother requirement are that the detectors must also have high efficiency in the HXR region, good energy resolution, low background, low power requirements, and low sensitivity to radiation damage. For solar observations, the ability to handle high counting rates is also extremely desirable. The Rutherford Appleton Laboratory (RAL) in the UK has been developing the electronics for such a detector. Dubbed HEXITEC, for High Energy X-Ray Imaging Technology, this Application Specific Integrated Circuit (ASIC), can be bonded to 1- or 2- mm-thick Cadmium Telluride (CdTe) or Cadmium-Zinc-Telluride (CZT), to create a fine (250 µm pitch) HXR detector. The NASA Marshall Space Flight CenterMSFC and the Goddard Space Flight Center (GSFC) has been working with RAL over the past few years to develop these detectors to be used with HXR focusing telescopes. We present on recent results and capabilities as applied to solar observations.

  4. Cumulative luminosity distributions of Supergiant Fast X-ray Transients in hard X-rays

    CERN Document Server

    Paizis, A

    2014-01-01

    We have analyzed in a systematic way about nine years of INTEGRAL data (17-100 keV) focusing on Supergiant Fast X-ray Transients (SFXTs) and three classical High Mass X-ray Binaries (HMXBs). Our approach has been twofold: image based analysis, sampled over a ~ks time frame to investigate the long-term properties of the sources, and lightcurve based analysis, sampled over a 100s time frame to seize the fast variability of each source during its ~ks activity. We find that while the prototypical SFXTs (IGR J17544-2619, XTE J1739-302 and SAX J1818.6-1703) are among the sources with the lowest ~ks based duty cycle ($<$1% activity over nine years of data), when studied at the 100s level, they are the ones with the highest detection percentage, meaning that, when active, they tend to have many bright short-term flares with respect to the other SFXTs. To investigate in a coherent and self consistent way all the available results within a physical scenario, we have extracted cumulative luminosity distributions for ...

  5. Phase-contrast imaging using polychromatic hard X-rays

    International Nuclear Information System (INIS)

    In conventional radiography, X-rays which pass through an object along different paths are differentially absorbed, and the intensity pattern of the emerging beam records the distribution of absorbing materials within the sample. An alternative approach is phase-contrast radiography, which instead records variations of the phase of the emerging radiation. Such an approach offers improved contrast sensitivity, especially when imaging weakly absorbing samples. Unfortunately, current phase-contrast imaging techniques generally require highly monochromatic plane-wave radiation and sophisticated X-ray optics, so their use is greatly restricted. Here we describe and demonstrate a simplified scheme for phase-contrast imaging based on an X-ray source having high spatial (but essentially no chromatic) coherence. The method is compatible with conventional polychromatic micro-focus X-ray tube sources, is well suited to large areas of irradiation, can operate with a lower absorbed dose than traditional X-ray imaging techniques, and should find broad application in clinical, biological and industrial settings. (Author)

  6. Fluence thresholds for grazing incidence hard x-ray mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Aquila, A.; Ozkan, C.; Sinn, H.; Tschentscher, T.; Mancuso, A. P.; Gaudin, J. [European XFEL GmbH, Albert-Einstein-Ring 19, Hamburg D-22671 (Germany); Sobierajski, R.; Klepka, M. T.; Dłużewski, P.; Morawiec, K. [Institute of Physics, PAS Al. Lotnikw 32/46, Warsaw PL-02-668 (Poland); Hájková, V.; Burian, T.; Chalupský, J.; Juha, L. [Institute of Physics, ASCR, Na Slovance 2, CZ 182 21 Prague 8 (Czech Republic); Störmer, M. [Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, Geesthacht D-21502 (Germany); Bajt, S. [Deutsches Elektronen-Synchrotron, Notkestraße 85, Hamburg D-22607 (Germany); Ohashi, H.; Koyama, T.; Tono, K. [RIKEN/SPring-8 Kouto 1-1-1, Sayo, Hyogo 679-5148 (Japan); Japan Synchrotron Radiation Research Institute (JASRI), Kouto 1-1-1, Sayo, Hyogo 679-5198 (Japan); Inubushi, Y. [RIKEN/SPring-8 Kouto 1-1-1, Sayo, Hyogo 679-5148 (Japan); and others

    2015-06-15

    X-ray Free Electron Lasers (XFELs) have the potential to contribute to many fields of science and to enable many new avenues of research, in large part due to their orders of magnitude higher peak brilliance than existing and future synchrotrons. To best exploit this peak brilliance, these XFEL beams need to be focused to appropriate spot sizes. However, the survivability of X-ray optical components in these intense, femtosecond radiation conditions is not guaranteed. As mirror optics are routinely used at XFEL facilities, a physical understanding of the interaction between intense X-ray pulses and grazing incidence X-ray optics is desirable. We conducted single shot damage threshold fluence measurements on grazing incidence X-ray optics, with coatings of ruthenium and boron carbide, at the SPring-8 Angstrom compact free electron laser facility using 7 and 12 keV photon energies. The damage threshold dose limits were found to be orders of magnitude higher than would naively be expected. The incorporation of energy transport and dissipation via keV level energetic photoelectrons accounts for the observed damage threshold.

  7. Fluence thresholds for grazing incidence hard x-ray mirrors

    Science.gov (United States)

    Aquila, A.; Sobierajski, R.; Ozkan, C.; Hájková, V.; Burian, T.; Chalupský, J.; Juha, L.; Störmer, M.; Bajt, S.; Klepka, M. T.; DłuŻewski, P.; Morawiec, K.; Ohashi, H.; Koyama, T.; Tono, K.; Inubushi, Y.; Yabashi, M.; Sinn, H.; Tschentscher, T.; Mancuso, A. P.; Gaudin, J.

    2015-06-01

    X-ray Free Electron Lasers (XFELs) have the potential to contribute to many fields of science and to enable many new avenues of research, in large part due to their orders of magnitude higher peak brilliance than existing and future synchrotrons. To best exploit this peak brilliance, these XFEL beams need to be focused to appropriate spot sizes. However, the survivability of X-ray optical components in these intense, femtosecond radiation conditions is not guaranteed. As mirror optics are routinely used at XFEL facilities, a physical understanding of the interaction between intense X-ray pulses and grazing incidence X-ray optics is desirable. We conducted single shot damage threshold fluence measurements on grazing incidence X-ray optics, with coatings of ruthenium and boron carbide, at the SPring-8 Angstrom compact free electron laser facility using 7 and 12 keV photon energies. The damage threshold dose limits were found to be orders of magnitude higher than would naively be expected. The incorporation of energy transport and dissipation via keV level energetic photoelectrons accounts for the observed damage threshold.

  8. NuSTAR HARD X-RAY SURVEY OF THE GALACTIC CENTER REGION. I. HARD X-RAY MORPHOLOGY AND SPECTROSCOPY OF THE DIFFUSE EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Kaya; Hailey, Charles J.; Perez, Kerstin; Nynka, Melania; Zhang, Shuo; Canipe, Alicia M. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Krivonos, Roman; Tomsick, John A.; Barrière, Nicolas; Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Hong, Jaesub [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Ponti, Gabriele [Max-Planck-Institut f. extraterrestrische Physik, HEG, Garching (Germany); Bauer, Franz [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, 306, Santiago 22 (Chile); Alexander, David M. [Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Baganoff, Frederick K. [Kavli Institute for Astrophysics and Space Research, Massachusets Institute of Technology, Cambridge, MA 02139 (United States); Barret, Didier [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); Christensen, Finn E. [DTU Space—National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Forster, Karl [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Giommi, Paolo, E-mail: kaya@astro.columbia.edu [ASI Science Data Center, Via del Politecnico snc I-00133, Roma (Italy); and others

    2015-12-01

    We present the first sub-arcminute images of the Galactic Center above 10 keV, obtained with NuSTAR. NuSTAR resolves the hard X-ray source IGR J17456–2901 into non-thermal X-ray filaments, molecular clouds, point sources, and a previously unknown central component of hard X-ray emission (CHXE). NuSTAR detects four non-thermal X-ray filaments, extending the detection of their power-law spectra with Γ ∼ 1.3–2.3 up to ∼50 keV. A morphological and spectral study of the filaments suggests that their origin may be heterogeneous, where previous studies suggested a common origin in young pulsar wind nebulae (PWNe). NuSTAR detects non-thermal X-ray continuum emission spatially correlated with the 6.4 keV Fe Kα fluorescence line emission associated with two Sgr A molecular clouds: MC1 and the Bridge. Broadband X-ray spectral analysis with a Monte-Carlo based X-ray reflection model self-consistently determined their intrinsic column density (∼10{sup 23} cm{sup −2}), primary X-ray spectra (power-laws with Γ ∼ 2) and set a lower limit of the X-ray luminosity of Sgr A* flare illuminating the Sgr A clouds to L{sub X} ≳ 10{sup 38} erg s{sup −1}. Above ∼20 keV, hard X-ray emission in the central 10 pc region around Sgr A* consists of the candidate PWN G359.95–0.04 and the CHXE, possibly resulting from an unresolved population of massive CVs with white dwarf masses M{sub WD} ∼ 0.9 M{sub ⊙}. Spectral energy distribution analysis suggests that G359.95–0.04 is likely the hard X-ray counterpart of the ultra-high gamma-ray source HESS J1745–290, strongly favoring a leptonic origin of the GC TeV emission.

  9. A focused, hard X-ray look at ARP 299 with NuSTAR

    DEFF Research Database (Denmark)

    Ptak, A.; Hornschemeier, A.; Zezas, A.;

    2015-01-01

    -thick active galactic nucleus (AGN), and a 10-30 keV luminosity of 1.2 × 1043 erg s-1. The hard X-rays detected by NuSTAR above 10 keV are centered on the western nucleus, Arp 299-B, which previous X-ray observations have shown to be the primary source of neutral Fe-K emission. Other X-ray sources, including...

  10. Angular resolution measurements at SPring-8 of a hard x-ray optic for the New Hard X-ray Mission

    Science.gov (United States)

    Spiga, D.; Raimondi, L.; Furuzawa, A.; Basso, S.; Binda, R.; Borghi, G.; Cotroneo, V.; Grisoni, G.; Kunieda, H.; Marioni, F.; Matsumoto, H.; Mori, H.; Miyazawa, T.; Negri, B.; Orlandi, A.; Pareschi, G.; Salmaso, B.; Tagliaferri, G.; Uesugi, K.; Valsecchi, G.; Vernani, D.

    2011-09-01

    The realization of X-ray telescopes with imaging capabilities in the hard (> 10 keV) X-ray band requires the adoption of optics with shallow (=10 m shall be produced and tested. Full-illumination tests of such mirrors are usually performed with onground X-ray facilities, aimed at measuring their effective area and the angular resolution; however, they in general suffer from effects of the finite distance of the X-ray source, e.g. a loss of effective area for double reflection. These effects increase with the focal length of the mirror under test; hence a "partial" full-illumination measurement might not be fully representative of the in-flight performances. Indeed, a pencil beam test can be adopted to overcome this shortcoming, because a sector at a time is exposed to the X-ray flux, and the compensation of the beam divergence is achieved by tilting the optic. In this work we present the result of a hard X-ray test campaign performed at the BL20B2 beamline of the SPring-8 synchrotron radiation facility, aimed at characterizing the Point Spread Function (PSF) of a multilayer-coated Wolter-I mirror shell manufactured by Nickel electroforming. The mirror shell is a demonstrator for the NHXM hard X-ray imaging telescope (0.3 - 80 keV), with a predicted HEW (Half Energy Width) close to 20 arcsec. We show some reconstructed PSFs at monochromatic X-ray energies of 15 to 63 keV, and compare them with the PSFs computed from post-campaign metrology data, self-consistently treating profile and roughness data by means of a method based on the Fresnel diffraction theory. The modeling matches the measured PSFs accurately.

  11. Nanometer focusing of hard x rays by phase zone plates

    Science.gov (United States)

    Yun, W.; Lai, B.; Cai, Z.; Maser, J.; Legnini, D.; Gluskin, E.; Chen, Z.; Krasnoperova, A. A.; Vladimirsky, Y.; Cerrina, F.; Di Fabrizio, E.; Gentili, M.

    1999-05-01

    Focusing of 8 keV x rays to a spot size of 150 and 90 nm full width at half maximum have been demonstrated at the first- and third-order foci, respectively, of a phase zone plate (PZP). The PZP has a numerical aperture of 1.5 mrad and focusing efficiency of 13% for 8 keV x rays. A flux density gain of 121 000 was obtained at the first-order focus. In this article, the fabrication of the PZP and its experimental characterization are presented and some special applications are discussed.

  12. Hard X-ray irradiation of cosmic silicate analogs: structural evolution and astrophysical implications

    CERN Document Server

    Gavilan, L; Simionovici, A; Lemaire, J L; Sabri, T; Foy, E; Yagoubi, S; Henning, T; Salomon, D; Martinez-Criado, G

    2016-01-01

    Protoplanetary disks, interstellar clouds, and active galactic nuclei, contain X-ray dominated regions. X-rays interact with the dust and gas present in such environments. While a few laboratory X-ray irradiation experiments have been performed on ices, X-ray irradiation experiments on bare cosmic dust analogs have been scarce up to now. Our goal is to study the effects of hard X-rays on cosmic dust analogs via in-situ X-ray diffraction. By using a hard X-ray synchrotron nanobeam, we seek to simulate cumulative X-ray exposure on dust grains during their lifetime in these astrophysical environments, and provide an upper limit on the effect of hard X-rays on dust grain structure. We prepared enstatite nanograins, analogs to cosmic silicates, via the melting-quenching technique. These amorphous grains were then annealed to obtain polycrystalline grains. These were characterized via scanning electron microscopy and high-resolution transmission electron microscopy before irradiation. Powder samples were prepared i...

  13. Suzaku Detection of Diffuse Hard X-Ray Emission outside Vela X

    CERN Document Server

    Katsuda, Satoru; Petre, Robert; Yamaguchi, Hiroya; Tsunemi, Hiroshi; Bocchino, Fabrizio; Bamba, Aya; Miceli, Marco; Hewitt, John W; Temim, Tea; Uchida, Hiroyuki; Yoshii, Rie

    2011-01-01

    Vela X is a large, 3x2 degrees, radio-emitting pulsar wind nebula (PWN) powered by the Vela pulsar in the Vela supernova remnant. Using four Suzaku/XIS observations pointed just outside Vela X, we find hard X-ray emission extending throughout the fields of view. The hard X-ray spectra are well represented by a power-law. The photon index is measured to be constant at Gamma~2.4, similar to that of the southern outer part of Vela X. The power-law flux decreases with increasing distance from the pulsar. These properties lead us to propose that the hard X-ray emission is associated with the Vela PWN. The larger X-ray extension found in this work strongly suggests that distinct populations relativistic electrons form the X-ray PWN and Vela X, as was recently inferred from multiwavelength spectral modeling of Vela X.

  14. Angular resolution measurements at SPring-8 of a hard X-ray optic for the New Hard X-ray Mission

    CERN Document Server

    Spiga, D; Furuzawa, A; Basso, S; Binda, R; Borghi, G; Cotroneo, V; Grisoni, G; Kunieda, H; Marioni, F; Matsumoto, H; Mori, H; Miyazawa, T; Negri, B; Orlandi, A; Pareschi, G; Salmaso, B; Tagliaferri, G; Uesugi, K; Valsecchi, G; Vernani, D

    2015-01-01

    The realization of X-ray telescopes with imaging capabilities in the hard (> 10 keV) X-ray band requires the adoption of optics with shallow (10 m shall be produced and tested. Full-illumination tests of such mirrors are usually performed with on- ground X-ray facilities, aimed at measuring their effective area and the angular resolution; however, they in general suffer from effects of the finite distance of the X-ray source, e.g. a loss of effective area for double reflection. These effects increase with the focal length of the mirror under test; hence a "partial" full-illumination measurement might not be fully representative of the in-flight performances. Indeed, a pencil beam test can be adopted to overcome this shortcoming, because a sector at a time is exposed to the X-ray flux, and the compensation of the beam divergence is achieved by tilting the optic. In this work we present the result of a hard X-ray test campaign performed at the BL20B2 beamline of the SPring-8 synchrotron radiation facility, aime...

  15. Optical constants in the hard x-ray/soft gamma-ray range

    DEFF Research Database (Denmark)

    Cooper-Jensen, Carsten P.; Brejnholt, Nicolai; Romaine, S.;

    2008-01-01

    Future astrophysics missions operating in the hard X-ray/Soft Gamma ray range is slated to carry novel focusing telescopes based on the use of depth graded multilayer reflectors. Current design studies show that, at the foreseen focal lengths, it should be feasible to focus X-rays at energies as...

  16. A Hard X-Ray Power-Law Spectral Cutoff in Centaurus X-4

    DEFF Research Database (Denmark)

    Chakrabarty, Deepto; Tomsick, John A.; Grefenstette, Brian W.;

    2015-01-01

    The low-mass X-ray binary Cen X-4 is the brightest and closest (<1.2 kpc) quiescent neutron star transient. Previous 0.5-10 keV X-ray observations of Cen X-4 in quiescence identified two spectral components: soft thermal emission from the neutron star atmosphere and a hard power-law tail of unkno...

  17. Time-Resolved Hard X-Ray Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Kenneth Moya (NSTec); Ian McKennaa (NSTec); Thomas Keenana (NSTec); Michael Cuneob (Sandia)

    2007-03-01

    Wired array studies are being conducted at the SNL Z accelerator to maximize the x-ray generation for inertial confinement fusion targets and high energy density physics experiments. An integral component of these studies is the characterization of the time-resolved spectral content of the x-rays. Due to potential spatial anisotropy in the emitted radiation, it is also critical to diagnose the time-evolved spectral content in a space-resolved manner. To accomplish these two measurement goals, we developed an x-ray spectrometer using a set of high-speed detectors (silicon PIN diodes) with a collimated field-of-view that converged on a 1-cm-diameter spot at the pinch axis. Spectral discrimination is achieved by placing high Z absorbers in front of these detectors. We built two spectrometers to permit simultaneous different angular views of the emitted radiation. Spectral data have been acquired from recent Z shots for the radial and polar views. UNSPEC1 has been adapted to analyze and unfold the measured data to reconstruct the x-ray spectrum. The unfold operator code, UFO2, is being adapted for a more comprehensive spectral unfolding treatment.

  18. Time-resolved hard x-ray spectrometer

    Science.gov (United States)

    Moy, Kenneth; Cuneo, Michael; McKenna, Ian; Keenan, Thomas; Sanford, Thomas; Mock, Ray

    2006-08-01

    Wired array studies are being conducted at the SNL Z accelerator to maximize the x-ray generation for inertial confinement fusion targets and high energy density physics experiments. An integral component of these studies is the characterization of the time-resolved spectral content of the x-rays. Due to potential spatial anisotropy in the emitted radiation, it is also critical to diagnose the time-evolved spectral content in a space-resolved manner. To accomplish these two measurement goals, we developed an x-ray spectrometer using a set of high-speed detectors (silicon PIN diodes) with a collimated field-of-view that converged on a 1-cm-diameter spot at the pinch axis. Spectral discrimination is achieved by placing high Z absorbers in front of these detectors. We built two spectrometers to permit simultaneous different angular views of the emitted radiation. Spectral data have been acquired from recent Z shots for the radial and axial (polar) views. UNSPEC 1 has been adapted to analyze and unfold the measured data to reconstruct the x-ray spectrum. The unfold operator code, UFO2, is being adapted for a more comprehensive spectral unfolding treatment.

  19. Identification of the Periodic Hard X-Ray Transient GRO J1849-03 with the X-Ray Pulsar GS 1843-02 = X1845-024 - a New Be/X-Ray Binary

    OpenAIRE

    Soffitta, P.; Tomsick, J. A.; Harmon, B.A.; Costa, E.; Ford, E. C.; M. Tavani(IASF of Rome/INAF); Zhang, S.N.; Kaaret, P.

    1997-01-01

    We identify the periodic transient hard X-ray source GRO J1849-03 with the transient x-ray pulsar GS 1843-02 = X1845-024 based on the detection of x-ray outbursts from X1845-024 coincident with hard x-ray outbursts of GRO J1849--03. Based on its spin period of 94.8 s and its orbital period of 241 days, we classify the system as a Be/X-ray binary.

  20. Hard X-ray irradiation of cosmic silicate analogs: structural evolution and astrophysical implications

    Science.gov (United States)

    Gavilan, L.; Jäger, C.; Simionovici, A.; Lemaire, J. L.; Sabri, T.; Foy, E.; Yagoubi, S.; Henning, T.; Salomon, D.; Martinez-Criado, G.

    2016-03-01

    Context. Protoplanetary disks, interstellar clouds, and active galactic nuclei contain X-ray-dominated regions. X-rays interact with the dust and gas present in such environments. While a few laboratory X-ray irradiation experiments have been performed on ices, X-ray irradiation experiments on bare cosmic dust analogs have been scarce up to now. Aims: Our goal is to study the effects of hard X-rays on cosmic dust analogs via in situ X-ray diffraction. By using a hard X-ray synchrotron nanobeam, we seek to simulate cumulative X-ray exposure on dust grains during their lifetime in these astrophysical environments and provide an upper limit on the effect of hard X-rays on dust grain structure. Methods: We prepared enstatite (MgSiO3) nanograins, which are analogs to cosmic silicates, via the melting-quenching technique. These amorphous grains were then annealed to obtain polycrystalline grains. These were characterized via scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) before irradiation. Powder samples were prepared in X-ray transparent substrates and were irradiated with hard X-rays nanobeams (29.4 keV) provided by beamline ID16B of the European Synchrotron Radiation Facility (Grenoble). X-ray diffraction images were recorded in transmission mode, and the ensuing diffractograms were analyzed as a function of the total X-ray exposure time. Results: We detected the amorphization of polycrystalline silicates embedded in an organic matrix after an accumulated X-ray exposure of 6.4 × 1027 eV cm-2. Pure crystalline silicate grains (without resin) do not exhibit amorphization. None of the amorphous silicate samples (pure and embedded in resin) underwent crystallization. We analyze the evolution of the polycrystalline sample embedded in an organic matrix as a function of X-ray exposure. Conclusions: Loss of diffraction peak intensity, peak broadening, and the disappearance of discrete spots and arcs reveal the amorphization

  1. Two-colored laser circulation system for monochromatic tunable hard x-ray source

    International Nuclear Information System (INIS)

    A two-colored laser pulse circulation system for a monochromatic tunable hard X-ray source via laser electron Compton scattering is investigated. The demonstration system of the X-ray source is under construction at the University of Tokyo. It consists of the X-band (11.424 GHz) electron linear accelerator and two Nd: YAG laser systems. The main advantage of this system is a monochromatic tunable hard X-ray. It is calculated that the X-ray intensity will be about 108 photons/s. In order to enhance the X-ray intensity for medical applications such as dual energy X-ray CT, a two-colored laser pulse circulation system has been designed. The laser pulse circulation experiment without an electron beam has been carried out by using a Nd: YAG laser fundamental wave (50 mJ) and a second harmonics wave (25 mJ). The result shows that the X-ray intensity can be enhanced by a factor of 10 times higher (i.e., up to 109 photons/s). This work is a part of the JST (Japan Science and Technology Agency) project. The entire X-ray source system is a part of a larger national project on the development of an advanced compact medical accelerator sponsored by the NIRS (National Institute for Radiological Science). The University of Tokyo and KEK are responsible for the X-ray source. (author)

  2. Impulsive and gradual hard X-ray sources in a solar flare

    Energy Technology Data Exchange (ETDEWEB)

    Vilmer, N.; Trotter, G.; Kane, S.R.

    1982-04-01

    Recent observations of a relatively large hard X-ray burst with well developed impulsive and gradual components are reported. The hard X-ray burst, which was observed with the X-ray spectrometer aboard the ISEE-3 (International Sun Earth Explorer-3) spacecraft, was associated with a relatively modest optical flare on 14 August 1979. During the impulsive phase, the X-ray maxima at different energies were essentially simultaneous. However, the gradual hard X-ray component exhibited energy-dependent time delays in temporal features observed before only in the largest flares such as the one on 4 August 1972. The present observations are consistent with a relatively high density (thick-target) source for the impulsive component and a medium density (n approx. equal to 6 10/sup 10/ cm/sup -3/) source with efficient electron trapping for the gradual hard X-ray component. The different temporal development of the impulsive and gradual hard X-ray components suggest large differences in the physical parameters of the ambient plasma. The present analysis indicates that the characteristic time of the injection processes during the gradual phase in large solar flares (approx. equal to 1 min) is larger than during the impulsive phase (approx. equal to 15 s). It also suggests that the total number of electrons injected is larger during the gradual phase than during the impulsive one.

  3. Hard disk drive based microsecond x-ray chopper for characterization of ionization chambers and photodiodes

    Science.gov (United States)

    Müller, O.; Lützenkirchen-Hecht, D.; Frahm, R.

    2015-03-01

    A fast X-ray chopper capable of producing ms long X-ray pulses with a typical rise time of few μs was realized. It is ideally suited to investigate the temporal response of X-ray detectors with response times of the order of μs to ms, in particular, any kind of ionization chambers and large area photo diodes. The drive mechanism consists of a brushless DC motor and driver electronics from a common hard disk drive, keeping the cost at an absolute minimum. Due to its simple construction and small dimensions, this chopper operates at home lab based X-ray tubes and synchrotron radiation sources as well. The dynamics of the most important detectors used in time resolved X-ray absorption spectroscopy, namely, ionization chambers and Passivated Implanted Planar Silicon photodiodes, were investigated in detail. The results emphasize the applicability of this X-ray chopper.

  4. Hard disk drive based microsecond x-ray chopper for characterization of ionization chambers and photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Müller, O., E-mail: o.mueller@uni-wuppertal.de; Lützenkirchen-Hecht, D.; Frahm, R. [Bergische Universität Wuppertal, Gaußstraße 20, Wuppertal 42119 (Germany)

    2015-03-15

    A fast X-ray chopper capable of producing ms long X-ray pulses with a typical rise time of few μs was realized. It is ideally suited to investigate the temporal response of X-ray detectors with response times of the order of μs to ms, in particular, any kind of ionization chambers and large area photo diodes. The drive mechanism consists of a brushless DC motor and driver electronics from a common hard disk drive, keeping the cost at an absolute minimum. Due to its simple construction and small dimensions, this chopper operates at home lab based X-ray tubes and synchrotron radiation sources as well. The dynamics of the most important detectors used in time resolved X-ray absorption spectroscopy, namely, ionization chambers and Passivated Implanted Planar Silicon photodiodes, were investigated in detail. The results emphasize the applicability of this X-ray chopper.

  5. Hard X-rays for processing hybrid organic-inorganic thick films.

    Science.gov (United States)

    Jiang, Yu; Carboni, Davide; Pinna, Alessandra; Marmiroli, Benedetta; Malfatti, Luca; Innocenzi, Plinio

    2016-01-01

    Hard X-rays, deriving from a synchrotron light source, have been used as an effective tool for processing hybrid organic-inorganic films and thick coatings up to several micrometres. These coatings could be directly modified, in terms of composition and properties, by controlled exposure to X-rays. The physico-chemical properties of the coatings, such as hardness, refractive index and fluorescence, can be properly tuned using the interaction of hard X-rays with the sol-gel hybrid films. The changes in the microstructure have been correlated especially with the modification of the optical and the mechanical properties. A relationship between the degradation rate of the organic groups and the rise of fluorescence from the hybrid material has been observed; nanoindentation analysis of the coatings as a function of the X-ray doses has shown a not linear dependence between thickness and film hardness.

  6. Hard X-ray identification of η Carinae and steadiness close to periastron

    Science.gov (United States)

    Leyder, J.-C.; Walter, R.; Rauw, G.

    2010-12-01

    Context. The colliding-wind binary η Carinae exhibits soft X-ray thermal emission that varies strongly around the periastron passage. It has been found to have non-thermal emission, thanks to its detection in hard X-rays using INTEGRAL and Suzaku, and also in γ-rays with AGILE and Fermi. Aims: This paper attempts to definitively identify η Carinae as the source of the hard X-ray emission, to examine how changes in the 2-10 keV band influence changes in the hard X-ray band, and to understand more clearly the mechanisms producing the non-thermal emission using new INTEGRAL observations obtained close to periastron passage. Methods: To strengthen the identification of η Carinae with the hard X-ray source, a long Chandra observation encompassing the INTEGRAL/ISGRI error circle was analysed, and all other soft X-ray sources (including the outer shell of η Carinae itself) were discarded as likely counter-parts. To expand the knowledge of the physical processes governing the X-ray lightcurve, new hard X-ray images of η Carinae were studied close to periastron, and compared to previous observations far from periastron. Results: The INTEGRAL component, when represented by a power law (with a photon index Γ of 1.8), would produce more emission in the Chandra band than observed from any point source in the ISGRI error circle apart from η Carinae, as long as the hydrogen column density to the ISGRI source is lower than NH ≲ 1024 cm-2. Sources with such a high absorption are very rare, thus the hard X-ray emission is very likely to be associated with η Carinae. The eventual contribution of the outer shell to the non-thermal component also remains fairly limited. Close to periastron passage, a 3-σ detection is achieved for the hard X-ray emission of η Carinae, with a flux similar to the average value far from periastron. Conclusions: Assuming a single absorption component for both the thermal and non-thermal sources, this 3-σ detection can be explained with a

  7. Tailoring a plasma focus as hard x-ray source for imaging

    Science.gov (United States)

    Hussain, S.; Shafiq, M.; Zakaullah, M.

    2010-01-01

    An investigation on temporal and spatial properties of hard x-rays (15-88 keV) emitted in a 5.3 kJ plasma focus using Si pin diodes and a pinhole camera is reported. The maximum yield of hard x-rays of 15-88 keV range is estimated about 4.7 J and corresponding efficiency for x-ray generation is 0.09%. The x-rays with energy >15 keV have 15-20 ns pulse duration and ˜1 mm source size. This radiation is used for contact x-ray imaging of biological and compound objects and spatial resolution of ˜50 μm is demonstrated.

  8. Flux monitoring hard X-ray optics in a single electrode configuration

    CERN Document Server

    Stoupin, Stanislav; Katsoudas, John

    2014-01-01

    To explore possibilities for X-ray flux monitoring on optical elements electrical responses of silicon and diamond single crystals and that of an X-ray mirror were studied under exposure to hard X-rays in a single electrode configuration in ambient air. To introduce flux monitoring as a non-invasive capability a platinum electrode was deposited on a small unexposed portion of the entrance surface of the crystals while for the X-ray mirror the entire mirror surface served as an electrode. It was found that the electrical responses are affected by photoemission and photoionization of the surrounding air. The influence of these factors was quantified using estimations of total electron yield and the ionization current. It is shown that both phenomena can be used for the non-invasive monitoring of hard X-ray flux on the optical elements. Relevant limits of applicability such as detection sensitivity and charge collection efficiency are identified and discussed.

  9. Design of grazing-incidence multilayer supermirrors for hard-X-ray reflectors

    DEFF Research Database (Denmark)

    Joensen, K. D.; Voutov, P.; Szentgyorgyi, A.;

    1995-01-01

    Extremely broadband grazing-incidence multilayers for hard-X-ray reflection can be obtained by a gradual change of the layer thicknesses down through the structure. Existing approaches for designing similar neutron optics, called supermirrors, are shown to provide respectable performance when app......-X-ray reflector and a hard-X-ray telescope) shows that an improved performance can be obtained. A multilayer whose bilayer thicknesses are given by a power law expression is found to provide the best solution; however, it is only slightly better than some of the adapted neutron designs...

  10. Surface roughness-aided hard X-ray emission from carbon nanotubes

    Indian Academy of Sciences (India)

    Suman Bagchi; P Prem Kiran; M K Bhuyan; M Krishnamurthy; K Yang; A M Rao; G Ravindra Kumar

    2010-12-01

    Efficient low debris hard X-ray source based on multiwalled carbon nanotubes (MWNT) irradiated by intense, femtosecond laser over an intensity range of 1015 –1017 W cm−2 2 is reported. The MWNT targets yield two orders of magnitude higher X-rays (indicating significant enhancement of laser coupling) and three orders of magnitude lower debris compared to conventional metallic targets under identical experimental conditions. The simple analytical model explains the basic experimental observations and also serves as a guide to design efficient targets to achieve low-debris laser plasma-based hard X-ray sources at low laser intensities suitable for multi-kHz operation.

  11. Hard X-ray Emission along the Z Track in GX 17 + 2

    Science.gov (United States)

    Ding, G. Q.; Huang, C. P.

    2015-09-01

    Using the data from the Proportional Counter Array (PCA) and the High-Energy X-ray Timing Experiment (HEXTE) on board Rossi X-Ray Timing Explorer for Z source GX 17 + 2, we investigate the evolution of its PCA spectra and HEXTE spectra along a `Z' track on its hardness-intensity diagram. A hard X-ray tail is detected in the HEXTE spectra. The detected hard X-ray tails are discontinuously scattered throughout the Z track. The found hard X-ray tail hardens from the horizontal branch, through the normal branch, to the flaring branch in principle and it contributes ˜(20-50)% of the total flux in 20-200 keV. Our joint fitting results of the PCA + HEXTE spectra in 3-200 keV show that the portion of Comptonization in the Bulk-Motion Comptonization (BMC) model accounts for the hard X-ray tail, which indicates that the BMC process could be responsible for the detected hard tail. The temperature of the seed photons for BMC is ˜2.7 keV, implying that these seed photons might be emitted from the surface of the neutron star (NS) or the boundary layer between the NS and the disk and, therefore, this process could take place around the NS or in the boundary layer.

  12. Hard X-ray photoemission with angular resolution and standing-wave excitation

    Energy Technology Data Exchange (ETDEWEB)

    Fadley, Charles S., E-mail: fadley@physics.ucdavis.edu [Department of Physics, University of California Davis, Davis, CA 95616 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2013-10-15

    Highlights: •Hard X-ray photoemission with angle resolution and standing-waves is discussed. •Hard X-ray angle-resolved photoemission yields k{sup →}-resolved bulk electronic structure. •Hard X-ray photoelectron diffraction provides element-specific atomic structure. •Multilayer standing-wave measurements add depth-resolved composition. •Standing-wave excitation also yields element-specific densities of states. -- Abstract: Several aspects of hard X-ray photoemission that make use of angular resolution and/or standing-wave excitation are discussed. These include hard X-ray angle-resolved photoemission (HARPES) from valence levels, which has the capability of determining bulk electronic structure in a momentum-resolved way; hard X-ray photoelectron diffraction (HXPD), which shows promise for studying element-specific bulk atomic structure, including dopant site occupations; and standing wave studies of the composition and chemical states of buried layers and interfaces. Beyond this, standing wave photoemission can be used to derive element-specific densities of states. Some recent examples relevant to all of these aspects are discussed.

  13. Hard X-ray Emission along the Z Track in GX 17+2

    Indian Academy of Sciences (India)

    G. Q. Ding; C. P. Huang

    2015-09-01

    Using the data from the Proportional Counter Array (PCA) and the High-Energy X-ray Timing Experiment (HEXTE) on board Rossi X-Ray Timing Explorer for Z source GX 17+2, we investigate the evolution of its PCA spectra and HEXTE spectra along a `Z’ track on its hardness-intensity diagram. A hard X-ray tail is detected in the HEXTE spectra. The detected hard X-ray tails are discontinuously scattered throughout the Z track. The found hard X-ray tail hardens from the horizontal branch, through the normal branch, to the flaring branch in principle and it contributes ∼ (20–50)% of the total flux in 20–200 keV. Our joint fitting results of the PCA+HEXTE spectra in 3–200 keV show that the portion of Comptonization in the Bulk-Motion Comptonization (BMC) model accounts for the hard X-ray tail, which indicates that the BMC process could be responsible for the detected hard tail. The temperature of the seed photons for BMC is ∼ 2.7 keV, implying that these seed photons might be emitted from the surface of the neutron star (NS) or the boundary layer between the NS and the disk and, therefore, this process could take place around the NS or in the boundary layer.

  14. Sub-Picosecond Tunable Hard X-Ray Undulator Source for Laser/X-Ray Pump-Probe Experiments

    Science.gov (United States)

    Ingold, G.; Beaud, P.; Johnson, S.; Streun, A.; Schmidt, T.; Abela, R.; Al-Adwan, A.; Abramsohn, D.; Böge, M.; Grolimund, D.; Keller, A.; Krasniqi, F.; Rivkin, L.; Rohrer, M.; Schilcher, T.; Schmidt, T.; Schlott, V.; Schulz, L.; van der Veen, F.; Zimoch, D.

    2007-01-01

    The FEMTO source under construction at the μXAS beamline is designed to enable tunable time-resolved laser/x-ray absorption and diffraction experiments in photochemistry and condensed matter with ps- and sub-ps resolution. The design takes advantage of (1) the highly stable operation of the SLS storage ring, (2) the reliable high harmonic operation of small gap, short period undulators to generate hard x-rays with energy 3-18 keV at 2.4 GeV beam energy, and (3) the progress in high power, high repetition rate fs solid-state laser technology to employ laser/e-beam `slicing' to reach a time resolution of ultimately 100 fs. The source will profit from the inherently synchronized pump (laser I: 100 fs, 2 mJ, 1 kHz) and probe (sliced X-rays, laser II: 50 fs, 5 mJ, 1 kHz) pulses, and from the excellent stability of the SLS storage ring which is operated in top-up mode and controlled by a fast orbit feedback (FOFB). Coherent radiation emitted at THz frequencies by the sliced 100 fs electron bunches will be monitored as on-line cross-correlation signal to keep the laser-electron beam interaction at optimum. The source is designed to provide at 8 keV (100 fs) a monochromized flux of 104 ph/s/0.01% bw (Si crystal monochromator) and 106 ph/s/1.5% bw (multilayer monochromator) at the sample. It is operated in parasitic mode using a hybrid bunch filling pattern. Because of the low intensity measurements are carried out repetitively over many shots using refreshing samples and gated detectors. `Diffraction gating' experiments will be used to characterize the sub-ps X-ray pulses.

  15. Hard X-ray imaging from the solar probe. [X ray telescope and mission planning

    Science.gov (United States)

    Hudson, H. S.

    1978-01-01

    The solar probe offers a platform with particular advantages for studying solar nonthermal plasma processes via the observations of hard X-radiation from energetic electrons in the chromosphere and corona, these include (1) high sensitivity, (2) a second line of sign (in addition to the earth's) that can aid in three dimensional reconstruction of the source distribution, and, (3) the possibility of correlation with direct measurements of the nonthermal particles from the probe itself.

  16. The BeppoSAX High Energy Large Area Survey. IV. On the soft X-ray properties of the hard X-ray-selected HELLAS sources

    CERN Document Server

    Vignali, C; Fiore, F; La Franca, F

    2001-01-01

    We present a comprehensive study of the soft X-ray properties of the BeppoSAX High-Energy Large Area Survey (HELLAS) sources. A large fraction (about 2/3) of the hard X-ray selected sources is detected by ROSAT. The soft X-ray colors for many of these objects, along with the 0.5-2 keV flux upper limits for those undetected in the ROSAT band, do imply the presence of absorption. The comparison with the ROSAT Deep Survey sources indicates that a larger fraction of absorbed objects among the HELLAS sources is present, in agreement with their hard X-ray selection and the predictions of the X-ray background synthesis models. Another striking result is the presence of a soft (additional) X-ray component in a significant fraction of absorbed objects.

  17. Linking Jet Emission, X-Ray States, and Hard X-Ray Tails in the Neutron Star X-Ray Binary GX 17+2

    NARCIS (Netherlands)

    S. Migliari; J.C.A. Miller-Jones; R.P. Fender; J. Homan; T. di Salvo; R.E. Rothschild; M.P. Rupen; J.A. Tomsick; R. Wijnands; M. van der Klis

    2007-01-01

    We present the results of simultaneous radio (VLA) and X-ray (RXTE) observations of the Z-type neutron star X-ray binary GX 17+2. The aim is to assess the coupling between X-ray and radio properties throughout its three rapidly variable X-ray states and during the time-resolved transitions. These ob

  18. Design of grazing-incidence multilayer supermirrors for hard-x-ray reflectors.

    Science.gov (United States)

    Joensen, K D; Voutov, P; Szentgyorgyi, A; Roll, J; Gorenstein, P; Høghøj, P; Christensen, F E

    1995-12-01

    Extremely broadband grazing-incidence multilayers for hard-x-ray reflection can be obtained by a gradual change of the layer thicknesses down through the structure. Existing approaches for designing similar neutron optics, called supermirrors, are shown to provide respectable performance when applied to x-ray multilayers. However, none of these approaches consider the effects of imperfect layer interfaces and absorption in the overlying layers. Adaptations of neutron designs that take these effects into account are presented, and a thorough analysis of two specific applications (a single hard-x-ray reflector and a hard-x-ray telescope) shows that an improved performance can be obtained. A multilayer whose bilayer thicknesses are given by a power law expression is found to provide the best solution; however, it is only slightly better than some of the adapted neutron designs.

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

    CERN Document Server

    Long, Ji; YuPeng, Chen; Shuang-Nan, Zhang; Diego, Torres F; Peter, Kretschmar; Jian, Li

    2013-01-01

    We report on a study of GS 1826--238 using all available {\\it RXTE} 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 promoted 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 $\\pm$ 1.2 seconds.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.

  20. Detectability of rotation-powered pulsars in future hard X-ray surveys

    Institute of Scientific and Technical Information of China (English)

    Wei Wang

    2009-01-01

    Recent INTEGRAL/IBIS hard X-ray surveys have detected about 10 young pulsars.We show hard X-ray properties of these 10 young pulsars,which have a luminosity of 10~(33)-10~(37) erg s~(-1) and a photon index of 1.6-2.1 in the energy range of 20-100 keV.The correlation between X-ray luminosity and spin-down power of L_X∝ L_(sd)~(1.31) suggests that the hard X-ray emission in rotation-powered pulsars is dominated by the pulsar wind nebula (PWN) component.Assuming spectral properties are similar in 20-100keV and 2-10 keV for both the pulsar and PWN components,the hard X-ray luminosity and flux of 39 known young X-ray pulsars and 8 millisecond pulsars are obtained,and a correlation of L_X ∝ L_(sd)~(1.5) is derived.About 20 known young X-ray pulsars and 1 millisecond pulsars could be detected with future INTEGRAL and HXMT surveys.We also carry out Monte Carlo simulations of hard X-ray pulsars in the Galaxy and the Gould Belt,assuming values for the pulsar birth rate,initial position,proper motion velocity,period,and magnetic field distribution and evolution based on observational statistics and the L_X - L_(sd) relations: L_X∝ L_(sd)~(1.31) and L_X∝ L_(sd)~(1.5).More than 40 young pulsars (mostly in the Galactic plane) could be detected after ten years of INTEGRAL surveys and the launch of HXMT.So,the young pulsars would be a significant part of the hard X-ray source population in the sky,and will contribute to unidentified hard X-ray sources in present and future hard X-ray surveys by INTEGRAL and HXMT.

  1. Hard X-rays from NGC 4151: A thermal origin?

    Science.gov (United States)

    Titarchuk, Lev; Mastichiadis, Apostolos

    1994-01-01

    We present a model for explaining the recent combined X-ray and low-energy gamma-ray observations of the Seyfert galaxy NGC 4151. According to this model, soft photons become Comptonized in a hot spot producing simultaneously the low-energy power law as observed by Ginga and the high-energy cutoff observed by the Oriented Scintillation Spectrometer Experiment (OSSE). Implementing recently developed theoretical calculations toward a generalized theory of Comptonization, we were able to find fits to the observations using only two parameters which characterize the physical quantities of the emission region: the plasma cloud optical depth and its temperature. We find that there is no need for additional nonthermal, reflection, or higher temperature thermal components to fit the aforementioned OSSE and Ginga observations. We derive in addition the size of the photon region and the temperature of the upscattered soft photons. We should emphasize, also, that any attempt at fitting only the high-energy parts of the spectrum (photon energies greater than 60 keV) by the Sunyaev & Titarchuk (1980) nonrelativistic Comptonization model leads to an underestimate of the Comptonization parameter y (or, equivalently, to an overestimation of the X-ray power-law spectral slope) and leads, as a result, to incorrect proportions between the low-energy and high-energy parts of the spectrum.

  2. Attitude determination for balloon-borne experiments

    CERN Document Server

    Gandilo, N N; Amiri, M; Angile, F E; Benton, S J; Bock, J J; Bond, J R; Bryan, S A; Chiang, H C; Contaldi, C R; Crill, B P; Devlin, M J; Dober, B; Dore, O P; Farhang, M; Filippini, J P; Fissel, L M; Fraisse, A A; Fukui, Y; Galitzki, N; Gambrel, A E; Golwala, S; Gudmundsson, J E; Halpern, M; Hasselfield, M; Hilton, G C; Holmes, W A; Hristov, V V; Irwin, K D; Jones, W C; Kermish, Z D; Klein, J; Korotkov, A L; Kuo, C L; MacTavish, C J; Mason, P V; Matthews, T G; Megerian, K G; Moncelsi, L; Morford, T A; Mroczkowski, T K; Nagy, J M; Netterfield, C B; Novak, G; Nutter, D; O'Brient, R; Pascale, E; Poidevin, F; Rahlin, A S; Reintsema, C D; Ruhl, J E; Runyan, M C; Savini, G; Scott, D; Shariff, J A; Soler, J D; Thomas, N E; Trangsrud, A; Truch, M D; Tucker, C E; Tucker, G S; Tucker, R S; Turner, A D; Ward-Thompson, D; Weber, A C; Wiebe, D V; Young, E Y

    2014-01-01

    An attitude determination system for balloon-borne experiments is presented. The system provides pointing information in azimuth and elevation for instruments flying on stratospheric balloons over Antarctica. In-flight attitude is given by the real-time combination of readings from star cameras, a magnetometer, sun sensors, GPS, gyroscopes, tilt sensors and an elevation encoder. Post-flight attitude reconstruction is determined from star camera solutions, interpolated by the gyroscopes using an extended Kalman Filter. The multi-sensor system was employed by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol), an experiment that measures polarized thermal emission from interstellar dust clouds. A similar system was designed for the upcoming flight of SPIDER, a Cosmic Microwave Background polarization experiment. The pointing requirements for these experiments are discussed, as well as the challenges in designing attitude reconstruction systems for high altitude balloon flights. ...

  3. Analysis of the 1980 November 18 limb flare observed by the hard X-ray imaging spectrometer (HXIS)

    NARCIS (Netherlands)

    Hoyng, P.; Haug, E.; Elwert, G.

    1984-01-01

    X-ray images of the 18 November 1980 limb flare taken by the HXIS instrument aboard SMM were analysed. The hard X-rays originated from three spots on the SW limb of the solar disk with different altitudes and time evolution. The locations of the brightest spots in hard and soft X-rays are compared w

  4. Development of microperiodic mirrors for hard x-ray phase-contrast imaging

    International Nuclear Information System (INIS)

    Differential phase-contrast imaging with hard x rays can have important applications in medicine, material sciences, and energy research. Phase-contrast methods based on microperiodic optics, such as shearing interferometry, are particularly attractive because they allow the use of conventional x-ray tubes. To enable shearing interferometry with x rays up to 100 keV, we propose using grazing-incidence microperiodic mirrors. In addition, a simple lithographic method is proposed for the production of the microperiodic x-ray mirrors, based on the difference in grazing-incidence reflectivity between a low-Z substrate and a high-Z film. Using this method, we produced prototype mirrors with 5-100 μm periods and 90 mm active length. Experimental tests with x rays up to 60 keV indicate good microperiodic mirror reflectivity and high-contrast fringe patterns, encouraging further development of the proposed imaging concept.

  5. Epoxy replication of hard X-ray supermirrors

    Institute of Scientific and Technical Information of China (English)

    Fangfang Wang; Wenbin Li; Qiushi Huang; Jingtao Zhu; Baozhong Mu; Zhanshan Wang

    2011-01-01

    @@ The direct replication of W/Si supermirrors is investigated systematically.W/Si supermirrors are fabricated by direct current(DC)magnetron sputtering technology.After deposition,the supermirrors are replicated from the supersmooth mandrels onto ordinary float glass substrates by epoxy replication technique.The properties of the supermirrors before and after the replication are characterized by grazing incidence X-ray reflectometry(GIXR)measurement and atomic force microscope(AFM).The results show that before and after replication,the multilayer structures are almost the same and that the surface roughness is 0.240 and 0.217 run,respectively,which are close to that of the mandrel.It is demonstrated that the W/Si supermirrors are successfully replicated from the mandrel with good performance.%The direct replication of W/Si supermirrors is investigated systematically. W/Si supermirrors are fabricated by direct current (DC) magnetron sputtering technology. After deposition, the supermirrors are replicated from the supersmooth mandrels onto ordinary float glass substrates by epoxy replication technique. The properties of the supermirrors before and after the replication are characterized by grazing incidence X-ray reflectometry (GIXR) measurement and atomic force microscope (AFM). The results show that before and after replication, the multilayer structures are almost the same and that the surface roughness is 0.240 and 0.217 nm, respectively, which are close to that of the mandrel. It is demonstrated that the W/Si supermirrors are successfully replicated from the mandrel with good performance.

  6. The hard X-ray emission along the "Z" track in GX 17+2

    CERN Document Server

    Ding, G Q

    2015-01-01

    Using the data from the Proportional Counter Array (PCA) and the High-Energy X-ray Timing Experiment (HEXTE) on board it Rossi X-Ray Timing Explorer for Z source GX 17+2, we investigate the evolution of its PCA spectra and HEXTE spectra along a "Z" track on its hardness-intensity diagram. A hard X-ray tail is detected in the HEXTE spectra. The detected hard X-ray tails are discontinuously scattered throughout the "Z" track. The found hard tail hardens from the horizontal branch, through the normal branch, to the flaring branch in principle and it contributes ~(20-50)% of the total flux in 20-200 keV. Our joint fitting results of the PCA+HEXTE spectra in 3-200 keV show that the portion of Comptonization in the bulk-motion Comptonization (BMC) model accounts for the hard X-ray tail, which indicates that the BMC process could be responsible for the detected hard tail. The temperature of the seed photons for BMC is ~2.7 keV, implying that these seed photons might be emitted from the surface of the neutron star (N...

  7. The hard X-ray view of Giga-Hertz Peaked Spectrum Radio Galaxies

    CERN Document Server

    Guainazzi, M; Stanghellini, C; Grandi, P; Piconcelli, E; Azibuke, C

    2005-01-01

    We present the first broadband X-ray observations of 4 Giga-Hertz Peaked Spectrum (GPS) radio galaxies at redshift 2 keV) X-rays. All sources were detected. Their radio-to-X-ray spectral energy distributions are similar, except for PKS0941-080, which is by about two orders of magnitude X-ray under-luminous. The comparison between the full sample of GPS galaxies with measurements in hard X-rays and a control sample of radio galaxies rules out intrinsic X-ray weakness as an origin for the lower detection rate of GPS sources in X-ray surveys. 4 out of 7 GPS galaxies exhibit large X-ray column densities, whereas for the remaining 3 this measurement is hampered by the poor spectral statistics. Bearing in mind the still low number statistics in both the GPS and the control sample, the average column density measured in GPS galaxies is larger than in FRI or Broad Line Region FRII radio galaxies, but consistent with that measured in High-Excitation FRII galaxies. This leads to locating the absorbing gas in an obscuri...

  8. eHXI: a permanently installed, hard x-ray imager for the National Ignition Facility

    Science.gov (United States)

    Döppner, T.; Bachmann, B.; Albert, F.; Bell, P.; Burns, S.; Celeste, J.; Chow, R.; Divol, L.; Dewald, E. L.; Hohenberger, M.; Huntington, C. M.; Izumi, N.; LaCaille, G.; Landen, O. L.; Palmer, N.; Park, H.-S.; Thomas, C. A.

    2016-06-01

    We have designed and built a multi-pinhole imaging system for high energy x-rays (>= 50 keV) that is permanently installed in the equatorial plane outside of the target chamber at the National Ignition Facility (NIF). It records absolutely-calibrated, time-integrated x-ray images with the same line-of-sight as the multi-channel, spatially integrating hard x-ray detector FFLEX [McDonald et al., Rev. Sci. Instrum. 75 (2004) 3753], having a side view of indirect-drive inertial confinement fusion (ICF) implosion targets. The equatorial hard x-ray imager (eHXI) has recorded images on the majority of ICF implosion experiments since May 2011. eHXI provides valuable information on hot electron distribution in hohlraum experiments, target alignment, potential hohlraum drive asymmetries and serves as a long term reference for the FFLEX diagnostics.

  9. Sapphire hard X-ray Fabry-Perot resonators for synchrotron experiments.

    Science.gov (United States)

    Tsai, Yi Wei; Wu, Yu Hsin; Chang, Ying Yi; Liu, Wen Chung; Liu, Hong Lin; Chu, Chia Hong; Chen, Pei Chi; Lin, Pao Te; Fu, Chien Chung; Chang, Shih Lin

    2016-05-01

    Hard X-ray Fabry-Perot resonators (FPRs) made from sapphire crystals were constructed and characterized. The FPRs consisted of two crystal plates, part of a monolithic crystal structure of Al2O3, acting as a pair of mirrors, for the backward reflection (0 0 0 30) of hard X-rays at 14.3147 keV. The dimensional accuracy during manufacturing and the defect density in the crystal in relation to the resonance efficiency of sapphire FPRs were analyzed from a theoretical standpoint based on X-ray cavity resonance and measurements using scanning electron microscopic and X-ray topographic techniques for crystal defects. Well defined resonance spectra of sapphire FPRs were successfully obtained, and were comparable with the theoretical predictions.

  10. Association between gradual hard X-ray emission and metric continua during large flares

    Science.gov (United States)

    Klein, L.; Pick, M.; Trottet, G.; Vilmer, N.; Anderson, K.; Kane, S.

    1983-01-01

    X-ray radiation is used to study coronal phenomena in conjunction with meter wave observations during some large solar flares. It is found that metric flare continua and moving type IV bursts are associated with gradual and long lasting (a few tens of minutes) microwave and hard X-ray emissions. The detailed temporal analysis reveals that although metric and hard X-ray sources are located at very different heights, both kinds of emission result from a common and continuous/repetitive injection of electrons in the corona. The late part of the metric event (stationary type IV burst) is only associated with soft X-ray radiation. This indicates that the mean energy of the radiating electrons is lower during stationary type IV bursts than during the earlier parts of the event.

  11. Impulsive and gradual hard X-ray sources in a solar flare

    Science.gov (United States)

    Vilmer, N.; Trotter, G.; Kane, S. R.

    1982-01-01

    The paper reports recent observations of a relatively large hard X-ray burst with well developed impulsive and gradual components, that was associated with a relatively modest optical flare on Aug. 14, 1979. The impulsive X-ray source has a much higher ion density and the electron injection in the phase is shorter in duration consisting of fewer energetic electrons than in the gradual phase. The gradual X-ray source seems to consist of a lower density region, probably bounded by a magnetic arch in which the energetic electrons are perfectly trapped. The different temporal development of the impulsive and gradual hard X-ray components suggest large differences in the physical parameters of the ambient plasma.

  12. Design and Tests of the Hard X-Ray Polarimeter X-Calibur

    Science.gov (United States)

    Beilicke, M.; Baring, M. G.; Barthelmy, S.; Binns, W. R.; Buckley, J.; Cowsik, R.; Dowkontt, P.; Garson, A.; Guo, Q.; Haba, Y.; Israel, M. H.; Kunieda, H.; Lee, K.; Matsumoto, H.; Miyazawa, T.; Okajima, T.; Schnittman, J.; Tamura, K.; Tueller, J.; Krawczynski, H.

    2012-01-01

    X-ray polarimetry promises to give qualitatively new information about high-energy astrophysical sources, such as binary black hole systems, micro-quasars, active galactic nuclei, and gamma-ray bursts. We designed, built and tested a hard X-ray polarimeter X-Calibur to be used in the focal plane of the InFOC(mu)S grazing incidence hard X-ray telescope. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 10 - 80 keY X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity.

  13. Hard X-Rays from a Complete Sample of the Brightest Ultraluminous Infrared Galaxies

    Science.gov (United States)

    Sanders, David B.

    2003-01-01

    We were awarded 70kS of XMM-Newton spacecraft time using the Epic pn camera to observe three ultraluminous infrared galaxies (ULIGs) in order to measure the spectral shape of their hard X-Ray emission, and to use this information to search for the presence of an highly obscured active galactic nucleus (AGN), and to separate out the contributions from a putative starburst. By observing three objects we hope to be able to better assess the role of AGN in the complete class of ULIGs and therefore to better constrain their contribution to the X-ray background. XMM-Newton was deemed to be better suited to our proposed measurements of ULIGs than the Chandra X-ray observatory due to its larger aperture and better sensitivity to hard (2-10 keV) X-rays.

  14. Achieving few-femtosecond time-sorting at hard X-ray free-electron lasers

    International Nuclear Information System (INIS)

    Recently, few-femtosecond pulses have become available at hard X-ray free-electron lasers. Coupled with the available sub-10 fs optical pulses, investigations into few-femtosecond dynamics are not far off. However, achieving sufficient synchronization between optical lasers and X-ray pulses continues to be challenging. We report a 'measure-and-sort' approach, which achieves sub-10 fs root-mean-squared (r.m.s.) error measurement at hard X-ray FELs, far beyond the 100-200 fs r.m.s. jitter limitations. This timing diagnostic, now routinely available at the Linac Coherent Light Source (LCLS), is based on ultrafast free-carrier generation in optically transparent materials. Correlation between two independent measurements enables unambiguous demonstration of ∼6 fs r.m.s. error in reporting the optical/X-ray delay, with single shot error suggesting the possibility of reaching few-femtosecond resolution. (authors)

  15. Suzaku observations of the hard X-ray spectrum of Vela Jr

    CERN Document Server

    Takeda, Sawako; Terada, Yukikatsu; Tashiro, Makoto S; Katsuda, Satoru; Yamazaki, Ryo; Ohira, Yutaka; Iwakiri, Wataru

    2016-01-01

    We report the results of Suzaku observations of the young supernova remnant, Vela Jr.\\ (RX J0852.0$-$4622), which is known to emit synchrotron X-rays, as well as TeV gamma-rays. Utilizing 39 Suzaku mapping observation data from Vela Jr., a significant hard X-ray emission is detected with the hard X-ray detector (HXD) from the north-west TeV-emitting region. The X-ray spectrum is well reproduced by a single power-law model with the photon index of 3.15$^{+1.18}_{-1.14}$ in the 12--22 keV band. Compiling this with the soft X-ray spectrum simultaneously observed with the X-ray imaging spectrometer (XIS) onboard Suzaku, we find that the wide-band X-ray spectrum in the 2--22 keV band is reproduced with a single power-law or concave broken power-law model, which are statistically consistent with each other. Whichever the model of a single or broken power-law is appropriate, clearly the spectrum has no rolloff structure. Applying this result to the method introduced in \\citet{yama2014}, we find that one-zone synchro...

  16. Application of an EMCCD Camera for Calibration of Hard X-Ray Telescopes

    DEFF Research Database (Denmark)

    Vogel, Julia K.; Pivovaroff, M. J.; Nagarkar, V. V.;

    2012-01-01

    high frame rates due to its controllable internal gain. Additionally, thick CsI(Tl) yields high detection efficiency for x-rays [6]. This type of detector has already proven to be a unique device very suitable for calibrations in astrophysics: such a camera was used to support the characterization...... of the performance for all NuSTAR optics [7]-[9]. Further optimization will enable similar cameras to be improved and used to calibrate x-ray telescopes for future space missions. In this paper, we discuss the advantages of using an EMCCD to calibrate hard x-ray optics. We will illustrate the promising features...

  17. The small dispersion of the mid IR -- hard X-ray correlation in AGN

    OpenAIRE

    Horst, Hannes; Smette, Alain; Gandhi, Poshak; Duschl, Wolfgang J.

    2006-01-01

    Context: We investigate mid-infrared and X-ray properties of the dusty torus in unification scenarios for active galactic nuclei. Aims: We use the relation between mid IR and hard X-ray luminosities to constrain AGN unification scenarios. Methods: With VISIR at the VLT, we have obtained the currently highest angular resolution (0".35 FWHM) narrow-band mid infrared images of the nuclei of 8 nearby Seyfert galaxies. Combining these observations with X-ray data from the literature we study the c...

  18. Coherent hard x rays from attosecond pulse train-assisted harmonic generation.

    Science.gov (United States)

    Klaiber, Michael; Hatsagortsyan, Karen Z; Müller, Carsten; Keitel, Christoph H

    2008-02-15

    High-order harmonic generation from atomic systems is considered in the crossed fields of a relativistically strong infrared laser and a weak attosecond pulse train of soft x rays. Due to one-photon ionization by the x-ray pulse, the ionized electron obtains a starting momentum that compensates the relativistic drift, which is induced by the laser magnetic field, and allows the electron to efficiently emit harmonic radiation upon recombination with the atomic core in the relativistic regime. This way, short pulses of coherent hard x rays of up to 40 keV energy can be generated. PMID:18278127

  19. Crystal optics for hard-X-ray spectroscopy of highly charged ions

    OpenAIRE

    Beyer, H.F.; Attia, D.; Banas, D.; Bigot, E. -O. Le; Bosch, F.; Dousse, Jean-Claude; Förster, E; Gumberidze, A.; Hagmann, S; Heß, S.; Hoszowska, J.; Indelicato, P.; Jagodzinski, P.; Kozhuharov, Chr.; Krings, Th.

    2009-01-01

    A twin crystal-spectrometer assembly, operated in the focusing compensated asymmetric Laue geometry has been developed for accurate spectroscopy of fast highly charged heavy ions in the hard-X-ray region. Coupled to the focusing crystal optics is a specially developed two-dimensional position-sensitive X-ray detector which is necessary for retaining spectral resolution also for fast moving sources. We summarize the crystal optics and demonstrate the usefulness of the instrument for spectrosco...

  20. Upper limits from hard X-ray observations of five BL Lacertae objects

    Science.gov (United States)

    Bezler, M.; Gruber, D. E.; Rothschild, R. E.

    1988-01-01

    Results are presented from hard X-ray observations of the five brightest X-ray BL Lacertae objects: PKS 0548-322, Mrk 421 (=1101+384), 2A 1219+305, Mrk 501 (=1652+398), and PKS 2155-304. The observations covered the energy range 15-165 keV from August 1977 to December 1978. The results are compared with previous studies.

  1. Characteristics of ultrafast K line hard x-ray source from femtosecond terawatt laser-produced plasma

    Institute of Scientific and Technical Information of China (English)

    陈敏; 陈建文; 高鸿奕; 陆培祥; 徐至展

    2003-01-01

    Theoretical studies and analytical scalings were carried out to find the optimized laser parameters and target conditions so that ultrashort hard x-ray pulses and high x-ray power could be achieved. The dependence of laser intensity and wavelength on the yield of K-shell x-ray emission was studied. We propose an optimal design for a foil target for producing high-yield hard x-ray pulses of customizing duration.

  2. A Hard X-Ray Power-Law Spectral Cutoff in Centaurus X-4

    CERN Document Server

    Chakrabarty, Deepto; Grefenstette, Brian W; Psaltis, Dimitrios; Bachetti, Matteo; Barret, Didier; Boggs, Steven E; Christensen, Finn E; Craig, William W; Fuerst, Felix; Hailey, Charles J; Harrison, Fiona A; Kaspi, Victoria A; Miller, Jon M; Nowak, Michael A; Rana, Vikram; Stern, Daniel; Wik, Daniel R; Wilms, Joern; Zhang, William W

    2014-01-01

    The low-mass X-ray binary Cen X-4 is the brightest and closest (<1.2 kpc) quiescent neutron star transient. Previous 0.5-10 keV X-ray observations of Cen X-4 in quiescence identified two spectral components: soft thermal emission from the neutron star atmosphere and a hard power-law tail of unknown origin. We report here on a simultaneous observation of Cen X-4 with NuSTAR (3-79 keV) and XMM-Newton (0.3-10 keV) in 2013 January, providing the first sensitive hard X-ray spectrum of a quiescent neutron star transient. The 0.3-79 keV luminosity was 1.1 x 10^(33) erg/s (for D=1kpc), with around 60 percent in the thermal component. We clearly detect a cutoff of the hard spectral tail above 10 keV, the first time such a feature has been detected in this source class. Comptonization and synchrotron shock origins for the hard X-ray emission are ruled out on physical grounds. However, the hard X-ray spectrum is well fit by a thermal bremsstrahlung model with an 18 keV electron temperature, which can be understood as...

  3. A hard X-ray view of the soft-excess in AGN

    CERN Document Server

    Boissay, Rozenn; Paltani, Stéphane

    2015-01-01

    An excess of X-ray emission below 1 keV, called soft-excess, is detected in a large fraction of Seyfert 1-1.5s. The origin of this feature remains debated, as several models have been suggested to explain it, including warm Comptonization and blurred ionized reflection. In order to constrain the origin of this component, we exploit the different behavior of these models above 10 keV. Ionized reflection covers a broad energy range, from the soft X-rays to the hard X-rays, while Comptonization drops very quickly in the soft X-rays. We present here the results of a study done on 102 Seyfert 1s (Sy 1.0, 1.2, 1.5 and NLSy1) from the Swift/BAT 70-Month Hard X-ray Survey catalog. The joint spectral analysis of Swift/BAT and XMM-Newton data allows a hard X-ray view of the soft-excess that is present in about 80% of the objects of our sample. We discuss how the soft-excess strength is linked to the reflection at high energy, to the photon index of the primary continuum and to the Eddington ratio. In particular, we fin...

  4. The Relationship Between Solar Radio and Hard X-ray Emission

    CERN Document Server

    White, Stephen M; Christe, Steven; Farnik, Frantislav; Kundu, Mukul R; Mann, Gottfried; Ning, Zongjun; Raulin, Jean-Pierre; Silva-Valio, Adriana V R; Saint-Hilaire, Pascal; Vilmer, Nicole; Warmuth, Alexander

    2011-01-01

    This review discusses the complementary relationship between radio and hard X-ray observations of the Sun using primarily results from the era of the Reuven Ramaty High Energy Solar Spectroscopic Imager satellite. A primary focus of joint radio and hard X-ray studies of solar flares uses observations of nonthermal gyrosynchrotron emission at radio wavelengths and bremsstrahlung hard X-rays to study the properties of electrons accelerated in the main flare site, since it is well established that these two emissions show very similar temporal behavior. A quantitative prescription is given for comparing the electron energy distributions derived separately from the two wavelength ranges: this is an important application with the potential for measuring the magnetic field strength in the flaring region, and reveals significant differences between the electrons in different energy ranges. Examples of the use of simultaneous data from the two wavelength ranges to derive physical conditions are then discussed, includ...

  5. An unusual hard x-ray source in the region of SN 1987A

    International Nuclear Information System (INIS)

    An unusual hard x-ray source was discovered in the region of SN 1987A from the x-ray astronomy satellite Ginga. The error box of 0.2 degrees x 0.3 degrees includes the supernova. The energy spectrum is very hard above 10 keV and quite unusual for any of the known classes of x-ray source. The source intensity showed a steady increase from July through August till early September, while no further increase was seen in the observations in late September and mid-October. The positional agreement, a steady brightening and an unusual hard spectrum argue for this source being SN 1987A. The flux in the range 10--30 keV on September 2--3 when the source was brightest is approximately 5 x 10- 11 ergs/cm2s

  6. Hard X-ray view of microlensing events in RX J1131-1231

    CERN Document Server

    Neronov, A; Walter, R

    2016-01-01

    RX J1131-1231 is a gravitationally lensed system which includes four images of a quasar lensed by an elliptical galaxy. The flux in the individual images is known to be affected by microlensing effect in the visible and X-ray bands. We study the multi-wavelength properties of RX J1131-1231 over a broad energy range, from optical to hard X-ray, during the periods of the microlensing caustic crossings. We aim to constrain the spatial extent of the X-ray emission region at different energies. We combine the data of the source monitoring in the visible band with the X-ray data of the Burst Alert Telescope (BAT) on board of SWIFT satellite and Chandra X-ray observatory. Inspecting the broad band spectrum and lightcurves of the source we identify several microlensing caustic crossing events, and study the details of variability of the source during these events. The caustic crossings of image A on MJD 55150 and 55500 produce strong variations of the overall X-ray flux from the source. In the soft X-ray band, the ca...

  7. Tracing the Reverberation Lag in the Hard State of Black Hole X-Ray Binaries

    Science.gov (United States)

    De Marco, B.; Ponti, G.; Muñoz-Darias, T.; Nandra, K.

    2015-11-01

    We report results obtained from a systematic analysis of X-ray lags in a sample of black hole X-ray binaries, with the aim of assessing the presence of reverberation lags and studying their evolution during outburst. We used XMM-Newton and simultaneous Rossi X-ray Timing Explorer (RXTE) observations to obtain broadband energy coverage of both the disk and the hard X-ray Comptonization components. In most cases the detection of reverberation lags is hampered by low levels of variability-power signal-to-noise ratio (typically when the source is in a soft state) and/or short exposure times. The most detailed study was possible for GX 339-4 in the hard state, which allowed us to characterize the evolution of X-ray lags as a function of luminosity in a single source. Over all the sampled frequencies (˜0.05-9 Hz), we observe the hard lags intrinsic to the power-law component, already well known from previous RXTE studies. The XMM-Newton soft X-ray response allows us to detail the disk variability. At low frequencies (long timescales) the disk component always leads the power-law component. On the other hand, a soft reverberation lag (ascribable to thermal reprocessing) is always detected at high frequencies (short timescales). The intrinsic amplitude of the reverberation lag decreases as the source luminosity and the disk fraction increase. This suggests that the distance between the X-ray source and the region of the optically thick disk where reprocessing occurs gradually decreases as GX 339-4 rises in luminosity through the hard state, possibly as a consequence of reduced disk truncation.

  8. 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.

  9. The Relationship Between Solar Radio and Hard X-ray Emission

    Science.gov (United States)

    White, S. M.; Benz, A. O.; Christe, S.; Fárník, F.; Kundu, M. R.; Mann, G.; Ning, Z.; Raulin, J.-P.; Silva-Válio, A. V. R.; Saint-Hilaire, P.; Vilmer, N.; Warmuth, A.

    2011-09-01

    This review discusses the complementary relationship between radio and hard X-ray observations of the Sun using primarily results from the era of the Reuven Ramaty High Energy Solar Spectroscopic Imager satellite. A primary focus of joint radio and hard X-ray studies of solar flares uses observations of nonthermal gyrosynchrotron emission at radio wavelengths and bremsstrahlung hard X-rays to study the properties of electrons accelerated in the main flare site, since it is well established that these two emissions show very similar temporal behavior. A quantitative prescription is given for comparing the electron energy distributions derived separately from the two wavelength ranges: this is an important application with the potential for measuring the magnetic field strength in the flaring region, and reveals significant differences between the electrons in different energy ranges. Examples of the use of simultaneous data from the two wavelength ranges to derive physical conditions are then discussed, including the case of microflares, and the comparison of images at radio and hard X-ray wavelengths is presented. There have been puzzling results obtained from observations of solar flares at millimeter and submillimeter wavelengths, and the comparison of these results with corresponding hard X-ray data is presented. Finally, the review discusses the association of hard X-ray releases with radio emission at decimeter and meter wavelengths, which is dominated by plasma emission (at lower frequencies) and electron cyclotron maser emission (at higher frequencies), both coherent emission mechanisms that require small numbers of energetic electrons. These comparisons show broad general associations but detailed correspondence remains more elusive.

  10. Characterization of a 20-nm hard x-ray focus by ptychographic coherent diffractive imaging

    Science.gov (United States)

    Vila-Comamala, Joan; Diaz, Ana; Guizar-Sicairos, Manuel; Gorelick, Sergey; Guzenko, Vitaliy A.; Karvinen, Petri; Kewish, Cameron M.; Färm, Elina; Ritala, Mikko; Mantion, Alexandre; Bunk, Oliver; Menzel, Andreas; David, Christian

    2011-09-01

    Recent advances in the fabrication of diffractive X-ray optics have boosted hard X-ray microscopy into spatial resolutions of 30 nm and below. Here, we demonstrate the fabrication of zone-doubled Fresnel zone plates for multi-keV photon energies (4-12 keV) with outermost zone widths down to 20 nm. However, the characterization of such elements is not straightforward using conventional methods such as knife edge scans on well-characterized test objects. To overcome this limitation, we have used ptychographic coherent diffractive imaging to characterize a 20 nm-wide X-ray focus produced by a zone-doubled Fresnel zone plate at a photon energy of 6.2 keV. An ordinary scanning transmission X-ray microscope was modified to acquire the ptychographic data from a strongly scattering test object. The ptychographic algorithms allowed for the reconstruction of the image of the test object as well as for the reconstruction of the focused hard X-ray beam waist, with high spatial resolution and dynamic range. This method yields a full description of the focusing performance of the Fresnel zone plate and we demonstrate the usefulness ptychographic coherent diffractive imaging for metrology and alignment of nanofocusing diffractive X-ray lenses.

  11. Achieving Hard X-ray Nanofocusing Using a Wedged Multilayer Laue Lens

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaojing [Brookhaven National Lab. (BNL), Upton, NY (United States); Conley, Raymond [Brookhaven National Lab. (BNL), Upton, NY (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Bouet, Nathalie [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhou, Juan [Brookhaven National Lab. (BNL), Upton, NY (United States); Macrander, Albert [Argonne National Lab. (ANL), Argonne, IL (United States); Maser, Jorg [Argonne National Lab. (ANL), Argonne, IL (United States); Yan, Hanfei [Brookhaven National Lab. (BNL), Upton, NY (United States); Nazaretski, Evgeny [Brookhaven National Lab. (BNL), Upton, NY (United States); Lauer, Kenneth [Brookhaven National Lab. (BNL), Upton, NY (United States); Harder, Ross [Argonne National Lab. (ANL), Argonne, IL (United States); Robinson, Ian K. [Univ. College London, Bloomsbury (United Kingdom); Research Complex at Harwell, Oxfordshire (United Kingdom); Kalbfleisch, Sebastian [Brookhaven National Lab. (BNL), Upton, NY (United States); Chu, Yong S. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-05-04

    Here, we report on the fabrication and the characterization of a wedged multilayer Laue lens for x-ray nanofocusing. The lens was fabricated using a sputtering deposition technique, in which a specially designed mask was employed to introduce a thickness gradient in the lateral direction of the multilayer. X-ray characterization shows an efficiency of 27% and a focus size of 26 nm at 14.6 keV, in a good agreement with theoretical calculations. Our results indicate that the desired wedging is achieved in the fabricated structure. Furthermore, we anticipate that continuous development on wedged MLLs will advance x-ray nanofocusing optics to new frontiers and enrich capabilities and opportunities for hard X-ray microscopy.

  12. Full-field hard x-ray microscopy with interdigitated silicon lenses

    CERN Document Server

    Simons, Hugh; Michael-Lindhard, Jonas; Jensen, Flemming; Hansen, Ole; Detlefs, Carsten; Poulsen, Henning Friis

    2015-01-01

    Full-field x-ray microscopy using x-ray objectives has become a mainstay of the biological and materials sciences. However, the inefficiency of existing objectives at x-ray energies above 15 keV has limited the technique to weakly absorbing or two-dimensional (2D) samples. Here, we show that significant gains in numerical aperture and spatial resolution may be possible at hard x-ray energies by using silicon-based optics comprising 'interdigitated' refractive silicon lenslets that alternate their focus between the horizontal and vertical directions. By capitalizing on the nano-manufacturing processes available to silicon, we show that it is possible to overcome the inherent inefficiencies of silicon-based optics and interdigitated geometries. As a proof-of-concept of Si-based interdigitated objectives, we demonstrate a prototype interdigitated lens with a resolution of ~255 nm at 17 keV.

  13. Cosmological evolution of supermassive black holes in galactic centers unveiled by hard X-ray observations.

    Science.gov (United States)

    Ueda, Yoshihiro

    2015-01-01

    We review the current understanding of the cosmological evolution of supermassive black holes in galactic centers elucidated by X-ray surveys of active galactic nuclei (AGNs). Hard X-ray observations at energies above 2 keV are the most efficient and complete tools to find "obscured" AGNs, which are dominant populations among all AGNs. Combinations of surveys with various flux limits and survey area have enabled us to determine the space number density and obscuration properties of AGNs as a function of luminosity and redshift. The results have essentially solved the origin of the X-ray background in the energy band below ∼10 keV. The downsizing (or anti-hierarchical) evolution that more luminous AGNs have the space-density peak at higher redshifts has been discovered, challenging theories of galaxy and black hole formation. Finally, we summarize unresolved issues on AGN evolution and prospects for future X-ray missions. PMID:25971656

  14. Full-field hard x-ray microscopy with interdigitated silicon lenses

    Science.gov (United States)

    Simons, Hugh; Stöhr, Frederik; Michael-Lindhard, Jonas; Jensen, Flemming; Hansen, Ole; Detlefs, Carsten; Poulsen, Henning Friis

    2016-01-01

    Full-field x-ray microscopy using x-ray objectives has become a mainstay of the biological and materials sciences. However, the inefficiency of existing objectives at x-ray energies above 15 keV has limited the technique to weakly absorbing or two-dimensional (2D) samples. Here, we show that significant gains in numerical aperture and spatial resolution may be possible at hard x-ray energies by using silicon-based optics comprising 'interdigitated' refractive silicon lenslets that alternate their focus between the horizontal and vertical directions. By capitalizing on the nano-manufacturing processes available to silicon, we show that it is possible to overcome the inherent inefficiencies of silicon-based optics and interdigitated geometries. As a proof-of-concept of Si-based interdigitated objectives, we demonstrate a prototype interdigitated lens with a resolution of ≈255 nm at 17 keV.

  15. Sub-100 nm hard X-ray microbeam generation with Fresnel zone plate optics

    CERN Document Server

    Takano, H; Takeuchi, A

    2003-01-01

    A hard X-ray focusing test of a Fresnel zone plate has been performed with a synchrotron radiation source at the undulator beamline 20XU of SPring-8. Fresnel zone plate with a radius of 150 mu m, and an outermost zone width of 100 nm was used for the X-ray focusing device. The 248-m-long beamline provides fully coherent illumination for the focusing device. The focused beam evaluated by the knife-edge-scan method and scanning microscope test using test charts. Nearly diffraction- limited focusing with a size of 120 nm was achieved for the first-order diffraction at 10 keV X-ray. Evaluation for the third order diffraction was also performed at 8 keV X-ray, and a focal size of 50 m has been obtained. (author)

  16. Cosmological evolution of supermassive black holes in galactic centers unveiled by hard X-ray observations.

    Science.gov (United States)

    Ueda, Yoshihiro

    2015-01-01

    We review the current understanding of the cosmological evolution of supermassive black holes in galactic centers elucidated by X-ray surveys of active galactic nuclei (AGNs). Hard X-ray observations at energies above 2 keV are the most efficient and complete tools to find "obscured" AGNs, which are dominant populations among all AGNs. Combinations of surveys with various flux limits and survey area have enabled us to determine the space number density and obscuration properties of AGNs as a function of luminosity and redshift. The results have essentially solved the origin of the X-ray background in the energy band below ∼10 keV. The downsizing (or anti-hierarchical) evolution that more luminous AGNs have the space-density peak at higher redshifts has been discovered, challenging theories of galaxy and black hole formation. Finally, we summarize unresolved issues on AGN evolution and prospects for future X-ray missions.

  17. Weak Hard X-ray Emission from Two Broad Absorption Line Quasars Observed with NuSTAR: Compton-thick Absorption or Intrinsic X-ray Weakness?

    CERN Document Server

    Luo, B; Alexander, D M; Harrison, F A; Stern, D; Bauer, F E; Boggs, S E; Christensen, F E; Comastri, A; Craig, W W; Fabian, A C; Farrah, D; Fiore, F; Fuerst, F; Grefenstette, B W; Hailey, C J; Hickox, R; Madsen, K K; Matt, G; Ogle, P; Risaliti, G; Saez, C; Teng, S H; Walton, D J; Zhang, W W

    2013-01-01

    We present NuSTAR hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are among the optically brightest BAL quasars, yet they are known to be significantly X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars). We would expect to obtain ~400-600 hard X-ray (>10 keV) photons with NuSTAR, provided that these photons are not significantly absorbed (NH<1E24 cm^{-2}). However, both BAL quasars are only detected in the softer NuSTAR bands (e.g., 4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either the shielding gas is highly Compton-thick or the two targets are intrinsically X-ray weak. We constrain the column densities for both to be NH~7E24 cm^{-2} if the weak hard X-ray emission is caused by obscuration from the shielding gas. We d...

  18. Thick and large area PIN diodes for hard X-ray astronomy

    CERN Document Server

    Ota, N; Sugizaki, M; Kaneda, M; Tamura, T; Ozawa, H; Kamae, T; Makishima, K; Takahashi, T; Tashiro, M; Fukazawa, Y; Kataoka, J; Yamaoka, K; Kubo, S; Tanihata, C; Uchiyama, Y; Matsuzaki, K; Iyomoto, N; Kokubun, M; Nakazawa, T; Kubota, A; Mizuno, T; Matsumoto, Y; Isobe, N; Terada, Y; Sugiho, M; Onishi, T; Kubo, H; Ikeda, H; Nomachi, M; Ohsugi, T; Muramatsu, M; Akahori, H

    1999-01-01

    Thick and large area PIN diodes for the hard X-ray astronomy in the 10-60 keV range are developed. To cover this energy range in a room temperature and in a low background environment, Si PIN junction diodes of 2 mm in thickness with 2.5 cm sup 2 in effective area were developed, and will be used in the bottom of the Phoswich Hard X-ray Detector (HXD), on-board the ASTRO-E satellite. Problems related to a high purity Si and a thick depletion layer during our development and performance of the PIN diodes are presented in detail.

  19. Simulation study of phase retrieval for hard X-ray in-line phase contrast imaging

    Institute of Scientific and Technical Information of China (English)

    YU; Bin; PENG; Xiang; TIAN; Jindong; NIU; Hanben; DIAO; Luh

    2005-01-01

    Two algorithms for the phase retrieval of hard X-ray in-line phase contrast imaging are presented. One is referred to as Iterative Angular Spectrum Algorithm (IASA) and the other is a hybrid algorithm that combines IASA with TIE (transport of intensity equation). The calculations of the algorithms are based on free space propagation of the angular spectrum. The new approaches are demonstrated with numerical simulations. Comparisons with other phase retrieval algorithms are also performed. It is shown that the phase retrieval method combining the IASA and TIE is a promising technique for the application of hard X-ray phase contrast imaging.

  20. A HARD X-RAY POWER-LAW SPECTRAL CUTOFF IN CENTAURUS X-4

    Energy Technology Data Exchange (ETDEWEB)

    Chakrabarty, Deepto; Nowak, Michael A. [MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Tomsick, John A.; Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Grefenstette, Brian W.; Fürst, Felix; Harrison, Fiona A.; Rana, Vikram [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Psaltis, Dimitrios [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Bachetti, Matteo; Barret, Didier [Observatoire Midi-Pyrénées, Université de Toulouse III - Paul Sabatier, F-31400 Toulouse (France); Christensen, Finn E. [Division of Astrophysics, National Space Institute, Technical University of Denmark, DK-2800 Lyngby (Denmark); Hailey, Charles J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Kaspi, Victoria M. [Department of Physics, McGill University, Montreal, PQ H3A 2T8 (Canada); Miller, Jon M. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Wik, Daniel R.; Zhang, William W. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Wilms, Jörn, E-mail: deepto@mit.edu [Dr. Karl-Remeis-Sternwarte and Erlangen Centre for Astroparticle Physics, Universität Erlangen-Nürnberg, D-96049 Bamberg (Germany)

    2014-12-20

    The low-mass X-ray binary (LMXB) Cen X-4 is the brightest and closest (<1.2 kpc) quiescent neutron star transient. Previous 0.5-10 keV X-ray observations of Cen X-4 in quiescence identified two spectral components: soft thermal emission from the neutron star atmosphere and a hard power-law tail of unknown origin. We report here on a simultaneous observation of Cen X-4 with NuSTAR (3-79 keV) and XMM-Newton (0.3-10 keV) in 2013 January, providing the first sensitive hard X-ray spectrum of a quiescent neutron star transient. The 0.3-79 keV luminosity was 1.1×10{sup 33} D{sub kpc}{sup 2} erg s{sup –1}, with ≅60% in the thermal component. We clearly detect a cutoff of the hard spectral tail above 10 keV, the first time such a feature has been detected in this source class. We show that thermal Comptonization and synchrotron shock origins for the hard X-ray emission are ruled out on physical grounds. However, the hard X-ray spectrum is well fit by a thermal bremsstrahlung model with kT{sub e} = 18 keV, which can be understood as arising either in a hot layer above the neutron star atmosphere or in a radiatively inefficient accretion flow. The power-law cutoff energy may be set by the degree of Compton cooling of the bremsstrahlung electrons by thermal seed photons from the neutron star surface. Lower thermal luminosities should lead to higher (possibly undetectable) cutoff energies. We compare Cen X-4's behavior with PSR J1023+0038, IGR J18245–2452, and XSS J12270–4859, which have shown transitions between LMXB and radio pulsar modes at a similar X-ray luminosity.

  1. Nustar Detection of Hard X-Ray Phase Lags from the Accreting Pulsar GS 0834-430

    DEFF Research Database (Denmark)

    Miyasaka, Hiromasa; Bachetti, Matteo; Harrison, Fiona A.;

    2013-01-01

    The Nuclear Spectroscopic Telescope Array hard X-ray telescope observed the transient Be/X-ray binary GS 0834-430 during its 2012 outburst-the first active state of this system observed in the past 19 yr. We performed timing and spectral analysis and measured the X-ray spectrum between 3-79 keV w...

  2. Hard X-rays from Ultra-Compact HII Regions in W49A

    CERN Document Server

    Tsujimoto, M; Feigelson, E D; Getman, K V; Broos, P S

    2006-01-01

    We report the Chandra detection of hard X-ray emission from the Welch ring in W49A, an organized structure of ultra-compact (UC) HII regions containing a dozen nascent early-type stars. Two UC HII regions are associated with hard X-ray emission in a deep Advanced CCD Imaging Spectrometer image exposed for 96.7 ks. One of the two X-ray sources has no near-infrared counterpart and is extended by ~5 arcsec, or ~0.3 pc, at a distance of ~11.4 kpc, which is spatially aligned with the cometary radio continuum emission associated with the UC HII region. The X-ray spectrum of the emission, when fit with a thermal model, indicates a heavily absorbed plasma with extinction of \\~5x10^{23}/cm^{2}, temperature of ~7 keV, and X-ray luminosity in the 3.0-8.0 keV band of ~3x10^{33} ergs/s. Both the luminosity and the size of the emission resemble the extended hard emission found in UC HII regions in Sagittarius B2, yet they are smaller by an order of magnitude than the emission found in massive star clusters such as NGC 3603...

  3. Tracing the reverberation lag in the hard state of black hole X-ray binaries

    CERN Document Server

    De Marco, B; Muñoz-Darias, T; Nandra, K

    2015-01-01

    We report results obtained from a systematic analysis of X-ray lags in a sample of black hole X-ray binaries, with the aim of assessing the presence of reverberation lags and studying their evolution during outburst. We used XMM-Newton and simultaneous RXTE observations to obtain broad-band energy coverage of both the disc and the hard X-ray Comptonization components. In most cases the detection of reverberation lags is hampered by low levels of variability signal-to-noise ratio (e.g. typically when the source is in a soft state) and/or short exposure times. The most detailed study was possible for GX 339-4 in the hard state, which allowed us to characterize the evolution of X-ray lags as a function of luminosity in a single source. Over all the sampled frequencies (~0.05-9 Hz) we observe the hard lags intrinsic to the power law component, already well-known from previous RXTE studies. The XMM-Newton soft X-ray response allows us to detail the disc variability. At low-frequencies (long time scales) the disc c...

  4. MODELING THE THERMAL DIFFUSE SOFT AND HARD X-RAY EMISSION IN M17

    Energy Technology Data Exchange (ETDEWEB)

    Velazquez, P. F.; Rodriguez-Gonzalez, A.; Esquivel, A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ap. 70-543, 04510 D.F. (Mexico); Rosado, M. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Ap. 70-248, 04510 D.F. (Mexico); Reyes-Iturbide, J., E-mail: pablo@nucleares.unam.mx, E-mail: ary@nucleares.unam.mx, E-mail: esquivel@nucleares.unam.mx, E-mail: margarit@astro.unam.mx [LATO-DCET/Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-000 Ilheus, BA (Brazil)

    2013-04-10

    We present numerical models of very young wind driven superbubbles. The parameters chosen for the simulations correspond to the particular case of the M17 nebula, but are appropriate for any young superbubble in which the wind sources have not completely dispersed their parental cloud. From the simulations, we computed the diffuse emission in the soft ([0.5-1.5] keV) and hard ([1.5-5] keV) X-ray bands. The total luminosity in our simulations agrees with the observations of Hyodo et al., about two orders of magnitude below the prediction of the standard model of Weaver et al.. The difference with respect to the standard (adiabatic) model is the inclusion of radiative cooling, which is still important in such young bubbles. We show that for this type of object the diffuse hard X-ray luminosity is significant compared to that of soft X-rays, contributing as much as 10% of the total luminosity, in contrast with more evolved bubbles where the hard X-ray emission is indeed negligible, being at least four orders of magnitude lower than the soft X-ray emission.

  5. Hard X-ray Detectability of Small Impulsive Heating Events in the Solar Corona

    Science.gov (United States)

    Glesener, L.; Klimchuk, J. A.; Bradshaw, S. J.; Marsh, A.; Krucker, S.; Christe, S.

    2015-12-01

    Impulsive heating events ("nanoflares") are a candidate to supply the solar corona with its ~2 MK temperature. These transient events can be studied using extreme ultraviolet and soft X-ray observations, among others. However, the impulsive events may occur in tenuous loops on small enough timescales that the heating is essentially not observed due to ionization timescales, and only the cooling phase is observed. Bremsstrahlung hard X-rays could serve as a more direct and prompt indicator of transient heating events. A hard X-ray spacecraft based on the direct-focusing technology pioneered by the Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket could search for these direct signatures. In this work, we use the hydrodynamical EBTEL code to simulate differential emission measures produced by individual heating events and by ensembles of such events. We then directly predict hard X-ray spectra and consider their observability by a future spaceborne FOXSI, and also by the RHESSI and NuSTAR spacecraft.

  6. Some future perspectives in soft- and hard- X-ray photoemission

    Energy Technology Data Exchange (ETDEWEB)

    Fadley, Charles S., E-mail: fadley@physics.ucdavis.edu [Department of Physics, University of California Davis, Davis, CA 95616 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Nemšák, Slavomir [Department of Physics, University of California Davis, Davis, CA 95616 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2014-08-15

    Highlights: • Polarization-dependent differential photoelectric cross sections in valence photoemission. • Bulk electronic structure from hard X-ray angle-resolved photoemission. • Depth-resolved photoemission using standing-wave and total reflection excitation. • Standing-wave ambient-pressure photoemission as a probe of solid–liquid interfaces. • Molecular dissociation dynamics from photoelectron holography with free-electron laser excitation. - Abstract: We discuss several recent developments in photoemission, with comments on their perspectives for the future. These include an adequate allowance for differential cross section effects in core- and valence-angular distributions, as well as more accurate one-step modeling of angle-resolved photoemission (ARPES); the use of higher photon energies from the soft- to hard- X-ray regime to permit probing bulk electronic structure and buried layers and interfaces; extending ARPES into the soft- and hard- X-ray regimes; tailoring the X-ray wave field through X-ray optical effects including standing waves, total reflection, and tuning through resonances; using standing-wave excitation to provide much enhanced depth sensitivity in studying solid/gas and solid/liquid interfaces; and applying photoelectron holography to time-resolved studies of molecular reactions and dissociation. Specific application examples include a magnetic semiconductor, multilayer structures of complex metal oxides, a thin water solution on a metal oxide surface, and a halo-substituted benzene molecule.

  7. 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...

  8. A bright point source of ultrashort hard x-rays from laser bioplasmas

    CERN Document Server

    Krishnamurthy, M; Lad, Amit D; Ahmad, Saima; Narayanan, V; Rajeev, R; Kundu, M; Kumar, G Ravindra; Ray, Krishanu

    2010-01-01

    Micro and nano structures scatter light and amplify local electric fields very effectively. Energy incident as intense ultrashort laser pulses can be converted to x-rays and hot electrons more efficiently with a substrate that suitably modifies the local fields. Here we demonstrate that coating a plain glass surface with a few micron thick layer of an ubiquitous microbe, {\\it Escherichia coli}, catapults the brightness of hard x-ray bremsstrahlung emission (up to 300 keV) by more than two orders of magnitude at an incident laser intensity of 10$^{16}$ W cm$^{-2}$. This increased yield is attributed to the local enhancement of electric fields around individual {\\it E. coli} cells and is reproduced by detailed particle-in-cell (PIC) simulations. This combination of laser plasmas and biological targets can lead to turnkey, multi-kilohertz and environmentally safe sources of hard x-rays.

  9. Multilayer coating facility for the HEFT hard x-ray telescope

    DEFF Research Database (Denmark)

    Cooper-Jensen, Carsten P.; Christensen, Finn Erland; Chen, Hubert;

    2001-01-01

    A planar magnetron sputtering facility has been established at the Danish Space Research Institute (DSRI) for the production coating of depth graded multilayers on the thermally slumped glass segments which form the basis for the hard X-ray telescope on the HEFT balloon project. The facility is c...... is capable of coating 20-45 mirrors segments in each run. The coatings are optimized W/Si coatings. The paper describes the facility, the results of the calibration and presents data for the X-ray testing of flight mirrors.......A planar magnetron sputtering facility has been established at the Danish Space Research Institute (DSRI) for the production coating of depth graded multilayers on the thermally slumped glass segments which form the basis for the hard X-ray telescope on the HEFT balloon project. The facility...

  10. Recent advances in synchrotron-based hard x-ray phase contrast imaging

    International Nuclear Information System (INIS)

    Ever since the first demonstration of phase contrast imaging (PCI) in the 1930s by Frits Zernike, people have realized the significant advantage of phase contrast over conventional absorption-based imaging in terms of sensitivity to ‘transparent’ features within specimens. Thus, x-ray phase contrast imaging (XPCI) holds great potential in studies of soft biological tissues, typically containing low Z elements such as C, H, O and N. Particularly when synchrotron hard x-rays are employed, the favourable brightness, energy tunability, monochromatic characteristics and penetration depth have dramatically enhanced the quality and variety of XPCI methods, which permit detection of the phase shift associated with 3D geometry of relatively large samples in a non-destructive manner. In this paper, we review recent advances in several synchrotron-based hard x-ray XPCI methods. Challenges and key factors in methodological development are discussed, and biological and medical applications are presented. (paper)

  11. Attitude determination for balloon-borne experiments

    Science.gov (United States)

    Gandilo, N. N.; Ade, P. A. R.; Amiri, M.; Angilè, F. E.; Benton, S. J.; Bock, J. J.; Bond, J. R.; Bryan, S. A.; Chiang, H. C.; Contaldi, C. R.; Crill, B. P.; Devlin, M. J.; Dober, B.; Doré, O. P.; Farhang, M.; Filippini, J. P.; Fissel, L. M.; Fraisse, A. A.; Fukui, Y.; Galitzki, N.; Gambrel, A. E.; Golwala, S.; Gudmundsson, J. E.; Halpern, M.; Hasselfield, M.; Hilton, G. C.; Holmes, W. A.; Hristov, V. V.; Irwin, K. D.; Jones, W. C.; Kermish, Z. D.; Klein, J.; Korotkov, A. L.; Kuo, C. L.; MacTavish, C. J.; Mason, P. V.; Matthews, T. G.; Megerian, K. G.; Moncelsi, L.; Morford, T. A.; Mroczkowski, T. K.; Nagy, J. M.; Netterfield, C. B.; Novak, G.; Nutter, D.; O'Brient, R.; Pascale, E.; Poidevin, F.; Rahlin, A. S.; Reintsema, C. D.; Ruhl, J. E.; Runyan, M. C.; Savini, G.; Scott, D.; Shariff, J. A.; Soler, J. D.; Thomas, N. E.; Trangsrud, A.; Truch, M. D.; Tucker, C. E.; Tucker, G. S.; Tucker, R. S.; Turner, A. D.; Ward-Thompson, D.; Weber, A. C.; Wiebe, D. V.; Young, E. Y.

    2014-07-01

    An attitude determination system for balloon-borne experiments is presented. The system provides pointing information in azimuth and elevation for instruments flying on stratospheric balloons over Antarctica. In-flight attitude is given by the real-time combination of readings from star cameras, a magnetometer, sun sensors, GPS, gyroscopes, tilt sensors and an elevation encoder. Post-flight attitude reconstruction is determined from star camera solutions, interpolated by the gyroscopes using an extended Kalman Filter. The multi-sensor system was employed by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol), an experiment that measures polarized thermal emission from interstellar dust clouds. A similar system was designed for the upcoming flight of Spider, a Cosmic Microwave Background polarization experiment. The pointing requirements for these experiments are discussed, as well as the challenges in designing attitude reconstruction systems for high altitude balloon flights. In the 2010 and 2012 BLASTPol flights from McMurdo Station, Antarctica, the system demonstrated an accuracy of < 5' rms in-flight, and < 5" rms post-flight.

  12. Characterisation and application of a laser-based hard x-ray source

    International Nuclear Information System (INIS)

    Hard X-rays are generated by focusing 110 fs laser pulses with intensities of about 1017 W/cm2 onto solid metal targets. Characteristic properties of this X-ray source are the small source size, the short pulse duration and the high peak flux. The aim of the present work was to characterise this X-ray source and to demonstrate possible applications. A comparison with other X-ray sources and conventional imaging techniques is made. Characterising measurements were performed, including source size, emission spectrum, temporal behaviour, source stability and the influence of various laser parameters. The emission spectrum was measured using both energy-dispersive solid-state detectors and wavelength-dispersive crystal spectroscopy. The conversion efficiency from laser light to X-ray radiation was measured for different target materials. The laser ablation from different targets was studied. The feasibility of special imaging techniques, e.g. differential imaging and time-gated imaging, was investigated both theoretically and experimentally. Differential imaging allows for selective imaging of contrast agents, while time-gated imaging can reduce the influence of scattered radiation in X-ray imaging. Time-gated imaging was demonstrated in different imaging geometries, both for planar imaging and computed tomography imaging. Reasonable agreement between theoretically calculated values and experimental results was obtained

  13. 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.

  14. 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.

  15. Bragg concentrators for hard (> 10keV) x-ray astronomy: Status report

    DEFF Research Database (Denmark)

    Pareschi, G.; Frontera, F.; Pasqualini, G.

    1997-01-01

    The use of focusing telescopes in hard X-ray (E > 10 keV) astronomy will provide better flux sensitivity and imaging performances with respect to the direct-viewing detectors, utilized until now. We present recent results obtained from our group regarding the possible use of Bragg-diffraction tec...

  16. 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

  17. Development of a CZT spectroscopic 3D imager prototype for hard X ray astronomy

    DEFF Research Database (Denmark)

    Auricchio, N.; Caroli, E.; Basili, A.;

    2013-01-01

    The development of focusing optics based on wide band Laue lenses operating from ∼60 keV up to several hundreds of keV is particularly challenging. This type of hard X-ray or gamma ray optics requires a high performance focal plane detector in order to exploit to the best its intrinsic capabiliti...

  18. Hard X-ray/soft gamma-ray telescope designs for future astrophysics missions

    DEFF Research Database (Denmark)

    Ferreira, Desiree Della Monica; Christensen, Finn Erland; Pivovaroff, Michael J.;

    2013-01-01

    We present several concept designs of hard X-ray/soft λ-ray focusing telescopes for future astrophysics missions. The designs are based on depth graded multilayer coatings. These have been successfully employed on the NuSTAR mission for energies up to 80 keV. Recent advances in demonstrating...

  19. Experimental study of hard X-rays emitted from meter-scale positive discharges in air

    NARCIS (Netherlands)

    Kochkin, P.O.; Nguyen, C.V.; Deursen, A. van; Ebert, U.

    2012-01-01

    We investigate structure and evolution of long positive spark breakdown; and we study at which stage pulses of hard x-rays are emitted. Positive high-voltage pulses of standardized lightning impulse wave form of about 1 MV were applied to about 1 m of ambient air. The discharge evolution was imaged

  20. The First Focused Hard X-ray Images of the Sun with NuSTAR

    CERN Document Server

    Grefenstette, Brian W; Krucker, Säm; Hudson, Hugh; Hannah, Iain G; Smith, David M; Vogel, Julia K; White, Stephen M; Madsen, Kristin K; Marsh, Andrew J; Caspi, Amir; Chen, Bin; Shih, Albert; Kuhar, Matej; Boggs, Steven E; Christensen, Finn E; Craig, William W; Forster, Karl; Hailey, Charles J; Harrison, Fiona A; Miyasaka, Hiromasa; Stern, Daniel; Zhang, William W

    2016-01-01

    We present results from the the first campaign of dedicated solar observations undertaken by the \\textit{Nuclear Spectroscopic Telescope ARray} ({\\em NuSTAR}) hard X-ray telescope. Designed as an astrophysics mission, {\\em NuSTAR} nonetheless has the capability of directly imaging the Sun at hard X-ray energies ($>$3~keV) with an increase in sensitivity of at least two magnitude compared to current non-focusing telescopes. In this paper we describe the scientific areas where \\textit{NuSTAR} will make major improvements on existing solar measurements. We report on the techniques used to observe the Sun with \\textit{NuSTAR}, their limitations and complications, and the procedures developed to optimize solar data quality derived from our experience with the initial solar observations. These first observations are briefly described, including the measurement of the Fe K-shell lines in a decaying X-class flare, hard X-ray emission from high in the solar corona, and full-disk hard X-ray images of the Sun.

  1. The variable hard x-ray emission of NGC 4945 as observed by NUSTAR

    DEFF Research Database (Denmark)

    Puccetti, Simonetta; Comastri, Andrea; Fiore, Fabrizio;

    2014-01-01

    We present a broadband (~0.5-79 keV) spectral and temporal analysis of multiple NuSTAR observations combined with archival Suzaku and Chandra data of NGC 4945, the brightest extragalactic source at 100 keV. We observe hard X-ray (>10 keV) flux and spectral variability, with flux variations of a f...

  2. Evidence for Intermediate Polars as the Origin of the Galactic Center Hard X-ray Emission

    DEFF Research Database (Denmark)

    Hailey, Charles J.; Mori, Kaya; Perez, Kerstin;

    2016-01-01

    Recently, unresolved hard (20-40 keV) X-ray emission has been discovered within the central 10 pc of the Galaxy, possibly indicating a large population of intermediate polars (IPs). Chandra and XMM-Newton measurements in the surrounding ∼50 pc imply a much lighter population of IPs with 〈MWD〉≈0.5...

  3. Application of an EMCCD camera for calibration of hard X-ray telescopes

    DEFF Research Database (Denmark)

    Vogel, Julia K.; Pivovaro, Michael J.; Craig, William W.;

    2012-01-01

    Recent technological innovations make it feasible to construct effcient hard x-ray telescopes for space-based astronomical missions. Focusing optics are capable of improving the sensitivity in the energy range above 10 keV by orders of magnitude compared to previously used instruments. The last d...

  4. HEXITEC: A Next Generation Hard X-ray Detector for Solar Observations

    Science.gov (United States)

    Ryan, Daniel; Christe, Steven; Shih, Albert; Inglis, Andrew R.; Gregory, Kyle; Baumgartner, Wayne H.; Gaskin, Jessica; Wilson-Hodge, Colleen; Seller, Paul; Wilson, Matthew; Veale, Matthew C.; Panessa, Marco

    2016-05-01

    There is an increasing demand in solar physics for high resolution X-ray spectroscopic imaging. Such observations would present ground-breaking opportunities to study the poorly understood high energy processes in the solar corona such as solar flares, coronal heating, etc. However, such observations require a new breed of solid-state detectors sensititve to high energy X-rays with fine independent pixels to subsample the point spread function (PSF) of the X-ray optics. They must also be capable of handling very high count rates as photon fluxes from solar flares often cause pileup in current detectors. The Rutherford Appleton Laboratory (RAL) has recently developed a new Cadmium Telluride (CdTe) detector system, dubbed HEXITEC (High Energy X-ray Imaging Technology). It is an 80x80 array of 250 micron independent pixels sensitive in the 4--80 keV band and capable of a high full frame readout rate of 10 kHz. HEXITEC provides the smallest independently read out pixels currently available, and are well matched to the few arcsecond PSF produced by the current and next generation hard X-ray focusing optics. NASA's Goddard and Marshall Space Flight Centers are collaborating with RAL to develop these detectors for use on future space-borne hard X-ray focusing telescopes. In this poster we show the latest results on HEXITEC's imaging capability, high read out rate, and energy sensitivity and reveal it to be ideal for such future instruments. The potential observations obtained by combining HEXITEC with the next generation of X-ray focusing optics could to revolutionize our understanding of high energy processes in the solar corona.

  5. SAXJ1712.6-3739: a persistent hard X-ray source as monitored with INTEGRAL

    CERN Document Server

    Fiocchi, Mariateresa; Ubertini, Pietro; De Cesare, Giovanni

    2007-01-01

    The X-ray source SAXJ1712.6-3739 is a very weak Low Mass X-ray Binary discovered in 1999 with BeppoSAX and located in the Galactic Center. This region has been deeply investigated by the INTEGRAL satellite with an unprecedented exposure time, giving us an unique opportunity to study the hard X-ray behavior also for weak objects. The spectral results are based on the systematic analysis of all INTEGRAL observations covering the source position performed between February 2003 and October 2006. SAXJ1712.6-3739 did not shows any flux variation along this period as well as compared to previous BeppoSAX observation. Hence, to better constrain the physical parameters we combined both instrument data. Long INTEGRAL monitoring reveals, for the first time, that this X-ray burster is a weak persistent source, displaying a X-ray spectrum extended to high energy and spending most of the time in a low luminosity hard state. The broad-band spectrum is well modeled with a simple Comptonized model with a seed photons temperat...

  6. In-Orbit Performance of the Hard X-ray Detector on board Suzaku

    CERN Document Server

    Kokubun, M; Takahashi, T; Murakami, T; Tashiro, M; Fukazawa, Y; Kamae, T; Madejski, G M; Nakazawa, K; Yamaoka, K; Terada, Y; Yonetoku, D; Watanabe, S; Tamagawa, T; Mizuno, T; Kubota, A; Isobe, N; Takahashi, I; Sato, G; Takahashi, H; Hong, S; Kawaharada, M; Kawano, N; Mitani, T; Murashima, M; Suzuki, M; Abe, K; Miyawaki, R; Ohno, M; Tanaka, T; Yanagida, T; Itoh, T; Ohnuki, K; Tamura, K; Endo, Y; Hirakuri, S; Hiruta, T; Kitaguchi, T; Kishishita, T; Sugita, S; Takeda, S; Enoto, T; Hirasawa, A; Katsuta, J; Matsumura, S; Onda, K; Sato, M; Ushio, M; Ishikawa, S; Murase, K; Odaka, H; Yaji, Y; Yamada, S; Yamasaki, T; Yuasa, T

    2006-01-01

    The in-orbit performance and calibration of the Hard X-ray Detector (HXD) on board the X-ray astronomy satellite Suzaku are described. Its basic performances, including a wide energy bandpass of 10-600 keV, energy resolutions of ~4 keV (FWHM) at 40 keV and ~11% at 511 keV, and a high background rejection efficiency, have been confirmed by extensive in-orbit calibrations. The long-term gains of PIN-Si diodes have been stable within 1% for half a year, and those of scintillators have decreased by 5-20%. The residual non-X-ray background of the HXD is the lowest among past non-imaging hard X-ray instruments in energy ranges of 15-70 and 150-500 keV. We provide accurate calibrations of energy responses, angular responses, timing accuracy of the HXD, and relative normalizations to the X-ray CCD cameras using multiple observations of the Crab Nebula.

  7. Probing bismuth ferrite nanoparticles by hard x-ray photoemission: Anomalous occurrence of metallic bismuth

    International Nuclear Information System (INIS)

    We have investigated bismuth ferrite nanoparticles (∼75 nm and ∼155 nm) synthesized by a chemical method, using soft X-ray (1253.6 eV) and hard X-ray (3500, 5500, and 7500 eV) photoelectron spectroscopy. This provided an evidence for the variation of chemical state of bismuth in crystalline, phase pure nanoparticles. X-ray photoelectron spectroscopy analysis using Mg Kα (1253.6 eV) source showed that iron and bismuth were present in both Fe3+ and Bi3+ valence states as expected for bismuth ferrite. However, hard X-ray photoelectron spectroscopy analysis of the bismuth ferrite nanoparticles using variable photon energies unexpectedly showed the presence of Bi0 valence state below the surface region, indicating that bismuth ferrite nanoparticles are chemically inhomogeneous in the radial direction. Consistently, small-angle X-ray scattering reveals a core-shell structure for these radial inhomogeneous nanoparticles.

  8. Ultrafast Time-Resolved Hard X-Ray Emission Spectroscopy on a Tabletop

    Science.gov (United States)

    Miaja-Avila, Luis; O'Neil, Galen C.; Joe, Young I.; Alpert, Bradley K.; Damrauer, Niels H.; Doriese, William B.; Fatur, Steven M.; Fowler, Joseph W.; Hilton, Gene C.; Jimenez, Ralph; Reintsema, Carl D.; Schmidt, Daniel R.; Silverman, Kevin L.; Swetz, Daniel S.; Tatsuno, Hideyuki; Ullom, Joel N.

    2016-07-01

    Experimental tools capable of monitoring both atomic and electronic structure on ultrafast (femtosecond to picosecond) time scales are needed for investigating photophysical processes fundamental to light harvesting, photocatalysis, energy and data storage, and optical display technologies. Time-resolved hard x-ray (>3 keV ) spectroscopies have proven valuable for these measurements due to their elemental specificity and sensitivity to geometric and electronic structures. Here, we present the first tabletop apparatus capable of performing time-resolved x-ray emission spectroscopy. The time resolution of the apparatus is better than 6 ps. By combining a compact laser-driven plasma source with a highly efficient array of microcalorimeter x-ray detectors, we are able to observe photoinduced spin changes in an archetypal polypyridyl iron complex [Fe (2 ,2'-bipyridine)3]2 + and accurately measure the lifetime of the quintet spin state. Our results demonstrate that ultrafast hard x-ray emission spectroscopy is no longer confined to large facilities and now can be performed in conventional laboratories with 10 times better time resolution than at synchrotrons. Our results are enabled, in part, by a 100- to 1000-fold increase in x-ray collection efficiency compared to current techniques.

  9. Hard X-ray activity of IGR J17473-2721

    DEFF Research Database (Denmark)

    Kuulkers, E.; Shaw, S.; Beckmann, V.;

    2008-01-01

    V with INTERAL/IBIS/ISGRI. The average hard X-ray flux during the Galactic bulge monitoring observations (see ATel #1385) which started on UT 2008 April 1, 16:55 of the source was 41+2 mCrab and 42+3 mCrab, at 18-40 keV and 40-100 keV, respectively, indicating a hard spectral state....

  10. Hard X-ray photoelectron and X-ray absorption spectroscopy characterization of oxidized surfaces of iron sulfides

    Science.gov (United States)

    Mikhlin, Yuri; Tomashevich, Yevgeny; Vorobyev, Sergey; Saikova, Svetlana; Romanchenko, Alexander; Félix, Roberto

    2016-11-01

    Hard X-ray photoelectron spectroscopy (HAXPES) using an excitation energy range of 2 keV to 6 keV in combination with Fe K- and S K-edge XANES, measured simultaneously in total electron (TEY) and partial fluorescence yield (PFY) modes, have been applied to study near-surface regions of natural polycrystalline pyrite FeS2 and pyrrhotite Fe1-xS before and after etching treatments in an acidic ferric chloride solution. It was found that the following near-surface regions are formed owing to the preferential release of iron from oxidized metal sulfide lattices: (i) a thin, no more than 1-4 nm in depth, outer layer containing polysulfide species, (ii) a layer exhibiting less pronounced stoichiometry deviations and low, if any, concentrations of polysulfide, the composition and dimensions of which vary for pyrite and pyrrhotite and depend on the chemical treatment, and (iii) an extended almost stoichiometric underlayer yielding modified TEY XANES spectra, probably, due to a higher content of defects. We suggest that the extended layered structure should heavily affect the near-surface electronic properties, and processes involving the surface and interfacial charge transfer.

  11. Cosmological Evolution of the Hard X-ray AGN Luminosity Function and the Origin of the Hard X-ray Background

    OpenAIRE

    Ueda, Yoshihiro; Akiyama, Masayuki; Ohta, Kouji; Miyaji, Takamitsu

    2003-01-01

    We investigate the cosmological evolution of the hard X-ray luminosity function (HXLF) of Active Galactic Nuclei (AGN) in the 2-10 keV luminosity range of 10^{41.5} - 10^{46.5} erg s^-1 as a function of redshift up to 3. From a combination of surveys conducted at photon energies above 2 keV with HEAO1, ASCA, and Chandra, we construct a highly complete (>96%) sample consisting of 247 AGNs over the wide flux range of 10^{-10} - 3.8*10^{-15} erg cm^-2 s^-1 (2-10 keV). For our purpose, we develop...

  12. Temporal evolution of an energetic electron population in an inhomogeneous medium: Application to solar hard X-ray bursts

    Science.gov (United States)

    Vilmer, N.; Mackinnon, A. L.; Trottet, G.

    1985-01-01

    Energetic electrons accelerated during solar flares can be studied through the hard X-ray emission they produce when interacting with the solar ambient atmosphere. In the case of the non thermal hard X-ray emission, the instanteous X-ray flux emitted at one point of the atmosphere is related to the instantaneous fast electron spectrum at that point. A hard X-ray source model then requires the understanding of the evolution in space and time of the fast particle distribution. The physical processes involved here are energy losses due to Coulomb collisions and pitch angle scattering due to both collisions and magnetic field gradients.

  13. Origin of Thermal and Non-Thermal Hard X-ray Emission from the Galactic Center

    CERN Document Server

    Dogiel, Vladimir; Yuasa, Takayuki; Prokhorov, Dmitrii; Cheng, Kwong-Sang; Bamba, Aya; Inoue, Hajime; Ko, Chung-Ming; Kokubun, Motohide; Maeda, Yoshitomo; Mitsuda, Kazuhisa; Nakazawa, Kazuhiro; Yamasaki, Noriko Y

    2009-01-01

    We analyse new results of Chandra and Suzaku which found a flux of hard X-ray emission from the compact region around Sgr A$^\\ast$ (r ~ 100 pc). We suppose that this emission is generated by accretion processes onto the central supermassive blackhole when an unbounded part of captured stars obtains an additional momentum. As a result a flux of subrelativistic protons is generated near the Galactic center which heats the background plasma up to temperatures about 6-10 keV and produces by inverse bremsstrahlung a flux of non-thermal X-ray emission in the energy range above 10 keV.

  14. Development of a Hard X-ray focal plane Compton Polarimeter: A compact polarimetric configuration with Scintillators and Si photomultipliers

    OpenAIRE

    Chattopadhyay, T.; Vadawale, S. V.; Goyal, S K; S., Mithun N. P.; Patel, A. R.; Shukla, R.; Ladiya, T.; M Shanmugam; Patel, V R; Ubale, G. P.

    2015-01-01

    X-ray polarization measurement of cosmic sources provides two unique parameters namely degree and angle of polarization which can probe the emission mechanism and geometry at close vicinity of the compact objects. Specifically, the hard X-ray polarimetry is more rewarding because the sources are expected to be intrinsically highly polarized at higher energies. With the successful implementation of Hard X-ray optics in NuSTAR, it is now feasible to conceive Compton polarimeters as focal plane ...

  15. Hard X-ray variability of V404 Cyg during the 2015 outburst

    CERN Document Server

    Sanchez-Fernandez, C; Motta, S E; Kuulkers, E

    2016-01-01

    Aims. Hard X-ray spectra of black hole binaries (BHB) are produced by Comptonization of soft seed photons by hot electrons near the black hole. The slope of the resulting energy spectra is governed by two main parameters: the electron temperature and the optical depth of the emitting plasma. Given the extreme brightness of V404 Cyg during the 2015 outburst, we aim to constraint the source spectral properties using an unprecedented time resolution in hard X-rays, and to monitor their evolution over the whole outburst. Methods. We have extracted and analyzed 602 X-ray spectra of V404 Cyg obtained during the 2015 June outburst by the IBIS/ISGRI instrument onboard INTEGRAL. We have performed time-resolved spectral analysis, using a time resolution ranging between 64 and 176000 seconds. The spectra were fitted in the 20-200 keV energy range. Results. We find that while the V404 Cyg light curve and soft X-ray spectra are remarkably different from other BHBs light curves, the spectral evolution of V404 Cyg in hard X...

  16. Observations of a hard X-ray component in the spectrum of Nova Ophiuchi

    Science.gov (United States)

    Wilson, C. K.; Rothschild, R. E.

    1983-01-01

    The spectrum and time variation of Nova Ophiuchi (H1705-25) in the 10-200 keV range as measured by the UCSD/MIT instruments aboard HEAO 1 during the period 1977 August 25 to September 28 are reported. The composite curve is best fitted by a kT = 2 keV thin thermal bremsstrahlung model below 10 keV and a separate hard X-ray component fitted equally well by a power-law component with photon index 2.19 + or - 0.06 or a kT = 32.1 + or - 2.4 keV thermal bremsstrahlung model. This is the first observation of a hard tail in the spectrum of a transient X-ray source with sufficient statistical significance to allow a detailed study of its spectral and temporal variability. It is found that the intensity variations of the high-energy X-rays are consistent with the variability at lower energies (3-6 keV), but no hard X-ray spectral index variability is found on time scales from 2 days to 2 weeks. The results can be interpreted as due to accretion onto a neutron star (or possibly onto a black hole) that may also be surrounded by an extended corona.

  17. A Hard X-Ray Power-law Spectral Cutoff in Centaurus X-4

    Science.gov (United States)

    Chakrabarty, Deepto; Tomsick, John A.; Grefenstette, Brian W.; Psaltis, Dimitrios; Bachetti, Matteo; Barret, Didier; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Fürst, Felix; Hailey, Charles J.; Harrison, Fiona A.; Kaspi, Victoria M.; Miller, Jon M.; Nowak, Michael A.; Rana, Vikram; Stern, Daniel; Wik, Daniel R.; Wilms, Jörn; Zhang, William W.

    2014-12-01

    The low-mass X-ray binary (LMXB) Cen X-4 is the brightest and closest (law tail of unknown origin. We report here on a simultaneous observation of Cen X-4 with NuSTAR (3-79 keV) and XMM-Newton (0.3-10 keV) in 2013 January, providing the first sensitive hard X-ray spectrum of a quiescent neutron star transient. The 0.3-79 keV luminosity was 1.1× 1033 D^2_kpc erg s-1, with sime60% in the thermal component. We clearly detect a cutoff of the hard spectral tail above 10 keV, the first time such a feature has been detected in this source class. We show that thermal Comptonization and synchrotron shock origins for the hard X-ray emission are ruled out on physical grounds. However, the hard X-ray spectrum is well fit by a thermal bremsstrahlung model with kTe = 18 keV, which can be understood as arising either in a hot layer above the neutron star atmosphere or in a radiatively inefficient accretion flow. The power-law cutoff energy may be set by the degree of Compton cooling of the bremsstrahlung electrons by thermal seed photons from the neutron star surface. Lower thermal luminosities should lead to higher (possibly undetectable) cutoff energies. We compare Cen X-4's behavior with PSR J1023+0038, IGR J18245-2452, and XSS J12270-4859, which have shown transitions between LMXB and radio pulsar modes at a similar X-ray luminosity.

  18. The column density distribution of hard X-ray radio galaxies

    Science.gov (United States)

    Panessa, F.; Bassani, L.; Landi, R.; Bazzano, A.; Dallacasa, D.; La Franca, F.; Malizia, A.; Venturi, T.; Ubertini, P.

    2016-09-01

    In order to investigate the role of absorption in active galactic nuclei (AGN) with jets, we have studied the column density distribution of a hard X-ray selected sample of radio galaxies, derived from the INTEGRAL/Imager on Board the Integral Satellite (IBIS) and Swift/The Burst Alert Telescope (BAT) AGN catalogues (˜7-10 per cent of the total AGN population). The 64 radio galaxies have a typical FR II radio morphology and are characterized by high 20-100 keV luminosities (from 1042 to 1046 erg s-1) and high Eddington ratios (log LBol/LEdd typically larger than ˜0.01). The observed fraction of absorbed AGN (NH > 1022 cm-2) is around 40 per cent among the total sample, and ˜75 per cent among type 2 AGN. The majority of obscured AGN are narrow-line objects, while unobscured AGN are broad-line objects, obeying to the zeroth-order predictions of unified models. A significant anti-correlation between the radio core dominance parameter and the X-ray column density is found. The observed fraction of Compton thick AGN is ˜2-3 per cent, in comparison with the 5-7 per cent found in radio-quiet hard X-ray selected AGN. We have estimated the absorption and Compton thick fractions in a hard X-ray sample containing both radio galaxies and non-radio galaxies and therefore affected by the same selection biases. No statistical significant difference was found in the absorption properties of radio galaxies and non-radio galaxies sample. In particular, the Compton thick objects are likely missing in both samples and the fraction of obscured radio galaxies appears to decrease with luminosity as observed in hard X-ray non-radio galaxies.

  19. Discovery of Diffuse Hard X-ray Emission associated with Jupiter

    Science.gov (United States)

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

    2009-12-01

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

  20. Nanofocusing of hard X-ray free electron laser pulses using diamond based Fresnel zone plates

    Science.gov (United States)

    David, C.; Gorelick, S.; Rutishauser, S.; Krzywinski, J.; Vila-Comamala, J.; Guzenko, V. A.; Bunk, O.; Färm, E.; Ritala, M.; Cammarata, M.; Fritz, D. M.; Barrett, R.; Samoylova, L.; Grünert, J.; Sinn, H.

    2011-08-01

    A growing number of X-ray sources based on the free-electron laser (XFEL) principle are presently under construction or have recently started operation. The intense, ultrashort pulses of these sources will enable new insights in many different fields of science. A key problem is to provide x-ray optical elements capable of collecting the largest possible fraction of the radiation and to focus into the smallest possible focus. As a key step towards this goal, we demonstrate here the first nanofocusing of hard XFEL pulses. We developed diamond based Fresnel zone plates capable of withstanding the full beam of the world's most powerful x-ray laser. Using an imprint technique, we measured the focal spot size, which was limited to 320 nm FWHM by the spectral band width of the source. A peak power density in the focal spot of 4×1017 W/cm2 was obtained at 70 fs pulse length.

  1. An exploratory study of the hard X-ray variability properties of PG quasars with RXTE

    CERN Document Server

    Guainazzi, M; Giallongo, E; Laor, A; Elvis, M; Siemiginowska, A L

    2000-01-01

    We have monitored with the RXTE PCA the variability pattern of the 2-20 keV flux in four PG quasars (QSOs) from the Laor et al. (1994) sample. Six observations of each target at regular intervals of 1 day were performed. The sample comprises objects with extreme values of Balmer line width (and hence soft X-ray steepness) and spans about one order of magnitude in luminosity. The most robust result is that the variability amplitude decreases as energy increases. Several options for a possible ultimate driver of the soft and hard X-ray variability, such as the influx rate of Comptonizing relativistic particles, instabilities in the accretion flow or the number of X-ray active sites, are consistent with our results.

  2. At-wavelength metrology of hard X-ray mirror using near field speckle.

    Science.gov (United States)

    Berujon, Sebastien; Wang, Hongchang; Alcock, Simon; Sawhney, Kawal

    2014-03-24

    We present a method to measure the surface profile of hard X-ray reflective optics with nanometer height accuracy and sub-millimetre lateral resolution. The technique uses X-ray near-field speckle, generated by a scattering membrane translated using a piezo motor, to infer the deflection of X-rays from the surface. The method provides a nano-radian order accuracy on the mirror slopes in both the tangential and sagittal directions. As a demonstration, a pair of focusing mirrors mounted in a Kirkpatrick-Baez (KB) configuration were characterized and the results were in good agreement with offline metrology data. It is hoped that the new technique will provide feedback to optic manufacturers to improve mirror fabrication and be useful for the online optimization of active, nano-focusing mirrors on modern synchrotron beamlines.

  3. Sputtered-sliced fabrication of kinoform zone plate for hard X-ray focusing

    Science.gov (United States)

    Yasumoto, M.; Tamura, S.; Kamijo, N.; Suzuki, Y.; Awaji, M.; Takeuchi, A.; Takano, H.

    2003-03-01

    We are planning to develop a kinoform zone plate (ZP) for hard X-ray using a sputtered-sliced (SS) method with two materials (Cu/Al). The SS kinoform ZP is composed of a Cu/Al multilayer that is based on radial modulation of the refractive indices of deposition materials. The X-ray through the zones interferes constructively at the focal point. The kinoform ZP, therefore, has an advantage of high focusing efficiency. According to the our theoretical calculation, the focusing efficiency of the Cu/Al kinoform PZP is up to 86% in the 0~30 keV X-ray energy region, while one of the conventional Cu/Al multilayer Fresnel zone plate is up to 38%.

  4. The Swift BAT Hard X-ray Survey - A New Window on the Local AGN Universe

    Science.gov (United States)

    Mushotzky, Richard

    2009-01-01

    The Swift Burst and Transient telescope (BAT) has surveyed the entire sky for the last 3.5 years obtaining the first sensitive all sky survey of the 14-195 keV sky. At high galactic latitudes the vast majority of the detected sources are AGN. Since hard x-rays penetrate all but Compton thick obscuring material (Column densities of 1.6E24 atms/cm2) this survey is unbiased with respect to obscuration, host galaxy type, optical , radio or IR properties. We will present results on the broad band x-ray properties, the nature of the host galaxies, the luminosity function and will discuss a few of the optical, IR and x-ray results in detail.

  5. High resolution energy-angle correlation measurement of hard x rays from laser-Thomson backscattering.

    Science.gov (United States)

    Jochmann, A; Irman, A; Bussmann, M; Couperus, J P; Cowan, T E; Debus, A D; Kuntzsch, M; Ledingham, K W D; Lehnert, U; Sauerbrey, R; Schlenvoigt, H P; Seipt, D; Stöhlker, Th; Thorn, D B; Trotsenko, S; Wagner, A; Schramm, U

    2013-09-13

    Thomson backscattering of intense laser pulses from relativistic electrons not only allows for the generation of bright x-ray pulses but also for the investigation of the complex particle dynamics at the interaction point. For this purpose a complete spectral characterization of a Thomson source powered by a compact linear electron accelerator is performed with unprecedented angular and energy resolution. A rigorous statistical analysis comparing experimental data to 3D simulations enables, e.g., the extraction of the angular distribution of electrons with 1.5% accuracy and, in total, provides predictive capability for the future high brightness hard x-ray source PHOENIX (photon electron collider for narrow bandwidth intense x rays) and potential gamma-ray sources.

  6. The Variable Crab Nebula: Evidence for a Connection Between GeV Flares and Hard X-ray Variations

    Science.gov (United States)

    Wilson-Hodge, Colleen A.; Harding, A. K.; Hays, E. A.; Cherry, M. L.; Case, G. L.; Finger, M. H.; Jenke, P.; Zhang, X.

    2016-01-01

    In 2010, hard X-ray variations (Wilson-Hodge et al. 2011) and GeV flares (Tavani et al 2011, Abdo et al. 2011) from the Crab Nebula were discovered. Connections between these two phenomena were unclear, in part because the timescales were quite different, with yearly variations in hard X-rays and hourly to daily variations in the GeV flares. The hard X-ray flux from the Crab Nebula has again declined since 2014, much like it did in 2008-2010. During both hard X-ray decline periods, the Fermi LAT detected no GeV flares, suggesting that injection of particles from the GeV flares produces the much slower and weaker hard X-ray variations. The timescale for the particles emitting the GeV flares to lose enough energy to emit synchrotron photons in hard X-rays is consistent with the yearly variations observed in hard X-rays and with the expectation that the timescale for variations slowly increases with decreasing energy. This hypothesis also predicts even slower and weaker variations below 10 keV, consistent with the non-detection of counterparts to the GeV flares by Chandra (Weisskopf et al 2013). We will present a comparison of the observed hard X-ray variations and a simple model of the decay of particles from the GeV flares to test our hypothesis.

  7. The Variable Crab Nebula: Evidence for a Connection between GeV flares and Hard X-ray Variations

    Science.gov (United States)

    Wilson-Hodge, Colleen A.; Kust Harding, Alice; Hays, Elizabeth A.; Cherry, Michael L.; Case, Gary L.; Finger, Mark H.; Jenke, Peter; Zhang, Xiao-Ling

    2016-04-01

    In 2010, hard X-ray variations (Wilson-Hodge et al. 2011) and GeV flares (Tavani et al 2011, Abdo et al. 2011) from the Crab Nebula were discovered. Connections between these two phenomena were unclear, in part because the timescales were quite different, with yearly variations in hard X-rays and hourly to daily variations in the GeV flares. The hard X-ray flux from the Crab Nebula has again declined since 2014, much like it did in 2008-2010. During both hard X-ray decline periods, the Fermi LAT detected no GeV flares, suggesting that injection of particles from the GeV flares produces the much slower and weaker hard X-ray variations. The timescale for the particles emitting the GeV flares to lose enough energy to emit synchrotron photons in hard X-rays is consistent with the yearly variations observed in hard X-rays and with the expectation that the timescale for variations slowly increases with decreasing energy. This hypothesis also predicts even slower and weaker variations below 10 keV, consistent with the non-detection of counterparts to the GeV flares by Chandra (Weisskopf et al 2013). We will present a comparison of the observed hard X-ray variations and a simple model of the decay of particles from the GeV flares to test our hypothesis.

  8. Possibilities and Challenges of Scanning Hard X-ray Spectro-microscopy Techniques in Material Sciences

    Directory of Open Access Journals (Sweden)

    Andrea Somogyi

    2015-06-01

    Full Text Available Scanning hard X-ray spectro-microscopic imaging opens unprecedented possibilities in the study of inhomogeneous samples at different length-scales. It gives insight into the spatial variation of the major and minor components, impurities and dopants of the sample, and their chemical and electronic states at micro- and nano-meter scales. Measuring, modelling and understanding novel properties of laterally confined structures are now attainable. The large penetration depth of hard X-rays (several keV to several 10 keV beam energy makes the study of layered and buried structures possible also in in situ and in operando conditions. The combination of different X-ray analytical techniques complementary to scanning spectro-microscopy, such as X-ray diffraction, X-ray excited optical luminescence, secondary ion mass spectrometry (SIMS and nano-SIMS, provides access to optical characteristics and strain and stress distributions. Complex sample environments (temperature, pressure, controlled atmosphere/vacuum, chemical environment are also possible and were demonstrated, and allow as well the combination with other analysis techniques (Raman spectroscopy, infrared imaging, mechanical tensile devices, etc. on precisely the very same area of the sample. The use of the coherence properties of X-rays from synchrotron sources is triggering emerging experimental imaging approaches with nanometer lateral resolution. New fast analytical possibilities pave the way towards statistically significant studies at multi- length-scales and three dimensional tomographic investigations. This paper gives an overview of these techniques and their recent achievements in the field of material sciences.

  9. Two distinct phases of hard x-ray emissions in a solar eruptive flare

    CERN Document Server

    Joshi, Bhuwan; Cho, K -S; Bong, S -C; Moon, Y -J; Lee, Jeongwoo; Somov, B V; Manoharan, P K; Kim, Y -H

    2008-01-01

    We present a detailed analysis of the evolution of an M7.6 flare that occurred near the south-east limb on October 24, 2003 utilizing a multi-wavelength data set. Preflare images at TRACE 195 A show that the bright and complex system of coronal loops already existed at the flaring site. The X-ray light curves clearly reveal two phases of flare evolution. The emission during the first phase is seen in GOES and RHESSI measurements at energies below 25 keV, while the second phase is evident in all the X-ray energies as high as 300 keV. The first phase is gradual whereas the second phase shows impulsive emission with several individual hard X-ray bursts. The first phase starts with the appearance of an X-ray loop-top (LT) source in RHESSI images below 25 keV. About 5 minute later, the TRACE 195 A images show an intense emission that is cospatial with RHESSI LT source. This hot and diffuse TRACE emission is attributed to the existence of 15-20 MK plasma, heated directly from the primary energy source. Both X-ray a...

  10. Staring/focusing lobster-eye hard x-ray imaging for non-astronomical objects

    Science.gov (United States)

    Gertsenshteyn, Michael; Jannson, Tomasz; Savant, Gajendra

    2005-08-01

    A new approach to hard X-ray imaging is proposed, based on staring optics consisting of a lobster-eye lens. This new Staring Imaging Lobster-Eye X-Ray approach is especially suited to X-ray lobster-eye imaging of non-astronomical objects at finite distances, because the staring optics replacing the standard scanning optics, result in an extremely efficient power budget, making possible not only the use of low-efficiency Compton backscattering but also operation with low-flux X-ray beams, increasing operator safety. The lobster-eye optics, consisting of square-cross-section microchannels, transmit an X-ray beam by total external reflection. This mode of operation has already been verified for viewing astronomical objects. Its major challenge is minimizing image defocusing by apodization. For this purpose, a new lens imaging equation is derived, and a new local optical axis concept is defined. Applications include medical imaging, cargo inspection, non-destructive testing, industrial and security safeguards, and surveillance.

  11. The multi-purpose hard X-ray beamline BL10 at the DELTA storage ring.

    Science.gov (United States)

    Lützenkirchen-Hecht, D; Wagner, R; Szillat, S; Hüsecken, A K; Istomin, K; Pietsch, U; Frahm, Ronald

    2014-07-01

    The layout and the characteristics of the hard X-ray beamline BL10 at the superconducting asymmetric wiggler at the 1.5 GeV Dortmund Electron Accelerator DELTA are described. This beamline is equipped with a Si(111) channel-cut monochromator and is dedicated to X-ray studies in the spectral range from ∼4 keV to ∼16 keV photon energy. There are two different endstations available. While X-ray absorption studies in different detection modes (transmission, fluorescence, reflectivity) can be performed on a designated table, a six-axis kappa diffractometer is installed for X-ray scattering and reflectivity experiments. Different detector set-ups are integrated into the beamline control software, i.e. gas-filled ionization chambers, different photodiodes, as well as a Pilatus 2D-detector are permanently available. The performance of the beamline is illustrated by high-quality X-ray absorption spectra from several reference compounds. First applications include temperature-dependent EXAFS experiments from liquid-nitrogen temperature in a bath cryostat up to ∼660 K by using a dedicated furnace. Besides transmission measurements, fluorescence detection for dilute sample systems as well as surface-sensitive reflection-mode experiments are presented.

  12. Communication: The electronic structure of matter probed with a single femtosecond hard x-ray pulse

    Directory of Open Access Journals (Sweden)

    J. Szlachetko

    2014-03-01

    Full Text Available Physical, biological, and chemical transformations are initiated by changes in the electronic configuration of the species involved. These electronic changes occur on the timescales of attoseconds (10−18 s to femtoseconds (10−15 s and drive all subsequent electronic reorganization as the system moves to a new equilibrium or quasi-equilibrium state. The ability to detect the dynamics of these electronic changes is crucial for understanding the potential energy surfaces upon which chemical and biological reactions take place. Here, we report on the determination of the electronic structure of matter using a single self-seeded femtosecond x-ray pulse from the Linac Coherent Light Source hard x-ray free electron laser. By measuring the high energy resolution off-resonant spectrum (HEROS, we were able to obtain information about the electronic density of states with a single femtosecond x-ray pulse. We show that the unoccupied electronic states of the scattering atom may be determined on a shot-to-shot basis and that the measured spectral shape is independent of the large intensity fluctuations of the incoming x-ray beam. Moreover, we demonstrate the chemical sensitivity and single-shot capability and limitations of HEROS, which enables the technique to track the electronic structural dynamics in matter on femtosecond time scales, making it an ideal probe technique for time-resolved X-ray experiments.

  13. Resonantly excited betatron hard X-Rays from Ionization Injected Electron Beam in a Laser Plasma Accelerator

    CERN Document Server

    Huang, K; Li, Y F; Li, D Z; Tao, M Z; Mirzaie, M; Ma, Y; Zhao, J R; Li, M H; Chen, M; Hafz, N; Sokollik, T; Sheng, Z M; Zhang, J

    2015-01-01

    A new scheme for bright hard x-ray emission from laser wakefield electron accelerator is reported, where pure nitrogen gas is adopted. Intense Betatron x-ray beams are generated from ionization injected K-shell electrons of nitrogen into the accelerating wave bucket. The x-ray radiation shows synchrotron-like spectrum with total photon yield 8$\\times$10$^8$/shot and $10^8$ over 110keV. In particular, the betatron hard x-ray photon yield is 10 times higher compared to the case of helium gas under the same laser parameters. Particle-in-cell simulation suggests that the enhancement of the x-ray yield results from ionization injection, which enables the electrons to be quickly accelerated to the driving laser region for subsequent betatron resonance. Employing the present scheme,the single stage nitrogen gas target could be used to generate stable high brightness betatron hard x-ray beams.

  14. Hard x-ray telescopes to be onboard ASTRO-H.

    Science.gov (United States)

    Awaki, Hisamitsu; Kunieda, Hideyo; Ishida, Manabu; Matsumoto, Hironori; Babazaki, Yasunori; Demoto, Tadatsugu; Furuzawa, Akihiro; Haba, Yoshito; Hayashi, Takayuki; Iizuka, Ryo; Ishibashi, Kazunori; Ishida, Naoki; Itoh, Masayuki; Iwase, Toshihiro; Kosaka, Tatsuro; Kurihara, Daichi; Kuroda, Yuuji; Maeda, Yoshitomo; Meshino, Yoshifumi; Mitsuishi, Ikuyuki; Miyata, Yuusuke; Miyazawa, Takuya; Mori, Hideyuki; Nagano, Housei; Namba, Yoshiharu; Ogasaka, Yasushi; Ogi, Keiji; Okajima, Takashi; Saji, Shigetaka; Shimasaki, Fumiya; Sato, Takuro; Sato, Toshiki; Sugita, Satoshi; Suzuki, Yoshio; Tachibana, Kenji; Tachibana, Sasagu; Takizawa, Shunya; Tamura, Keisuke; Tawara, Yuzuru; Torii, Tatsuharu; Uesugi, Kentato; Yamashita, Koujun; Yamauchi, Shigeo

    2014-11-10

    The new Japanese x-ray astronomy satellite, ASTRO-H, will carry two identical hard x-ray telescopes (HXTs), which cover the energy range of 5 to 80 keV. The HXT mirrors employ tightly nested, conically approximated thin-foil Wolter-I optics, and the mirror surfaces are coated with Pt/C depth-graded multilayers to enhance the hard x-ray effective area by means of Bragg reflection. The HXT comprises foils 120-450 mm in diameter and 200 mm in length, with a focal length of 12 m. To obtain a large effective area, 213 aluminum foils 0.2 mm in thickness are tightly nested confocally. The requirements for HXT are a total effective area of >300  cm2 at 30 keV and an angular resolution of ' in half-power diameter (HPD). Fabrication of two HXTs has been completed, and the x-ray performance of each HXT was measured at a synchrotron radiation facility, SPring-8 BL20B2 in Japan. Angular resolutions (HPD) of 1.9' and 1.8' at 30 keV were obtained for the full telescopes of HXT-1 and HXT-2, respectively. The total effective area of the two HXTs at 30 keV is 349  cm2.

  15. A Preliminary Research on the Development of the Hard X-ray Imaging Telescope

    Science.gov (United States)

    Zheng, Chun-Xiao; Cai, Ming-Sheng; Hu, Yi-Ming; Huang, Yong-Yi; Gong, Yi-Zhong

    2014-10-01

    The hard X-ray imaging telescope based on the Fourier transform imaging technique is introduced. The double-layer parallel gratings are used to make the modulation and coding on the light emerging from a celestial X-ray source, the modulated light is acquired, to make the optoelectronic conversion by scintillation crystal detectors, and finally read out by the electronic system. The modulation collimator X-ray telescopes can be divided into two types: the spatial modulation and temporal modulation. The temporal modulation system requires the scanning motion of the detector system, but the spatial modulation system requires no motion. The technology of grating fabrication is investigated, and the basic structure design of the collimators is given. The principal compo- nents of the prototype hard X-ray imaging telescope of spatial modulation type are successfully developed, including the 8 CsI crystal detector modules (contain- ing photomultipliers or PMTs), 8-channel shaping amplifiers (two of them are prepared for experiments), and the data acquisition system. And the preliminary test results of the electronic system are also given.

  16. A novel synthesis of polymeric CO via useful hard X-ray photochemistry

    Directory of Open Access Journals (Sweden)

    Michael Pravica

    2016-12-01

    Full Text Available We report on the synchrotron hard X-ray-induced decomposition of strontium oxalate (SrC2O4 pressurized to 7 GPa inside a diamond anvil cell (DAC. After some 4 h of irradiation in a white X-ray synchrotron beam, a dark reddish/brown region formed in the area of irradiation which was surrounded by a yellowish brown remainder in the rest of the sample. Upon depressurization of the sample to ambient conditions, the reacted/decomposed sample was recoverable as a dark brown/red and yellow waxy solid. Synchrotron infrared spectroscopy confirmed the strong presence of CO2 even under ambient conditions with the sample exposed to air and other strongly absorbing regions, suggesting that the sample may likely be polymerized CO (in part with dispersed CO2 and SrO trapped within the polymer. These results will have significant implications in the ability to readily produce and trap CO2 in situ via irradiation of a simple powder for useful hard X-ray photochemistry and in the ability to easily manufacture polymeric CO (via loading of powders in a DAC or high volume press without the need for the dangerous and complex loading of toxic CO. A novel means of X-ray-induced polymerization under extreme conditions has also been demonstrated.

  17. Weak Hard X-Ray Emission from Two Broad Absorption Line Quasars Observed with NuStar: Compton-Thick Absorption or Intrinsic X-Ray Weakness?

    Science.gov (United States)

    Luo, B.; Brandt, W. N.; Alexander, D. M.; Harrison, F. A.; Stern, D.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W..; Fabian, A. C.; Farrah, D.; Fiore, F.; Fuerst, F.; Grefenstette, B. W.; Hailey, C. J.; Hickox, R.; Madsen, K. K.; Matt, G.; Ogle, P.; Risaliti, G.; Saez, C.; Teng, S. H.; Walton, D. J.; Zhang, W. W.

    2013-01-01

    We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are among the optically brightest BAL quasars, yet they are known to be significantly X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars). We would expect to obtain approx. or equal to 400-600 hard X-ray (is greater than or equal to 10 keV) photons with NuSTAR, provided that these photons are not significantly absorbed N(sub H) is less than or equal to 10(exp24) cm(exp-2). However, both BAL quasars are only detected in the softer NuSTAR bands (e.g., 4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either the shielding gas is highly Compton-thick or the two targets are intrinsically X-ray weak. We constrain the column densities for both to be N(sub H) 7 × 10(exp 24) cm(exp-2) if the weak hard X-ray emission is caused by obscuration from the shielding gas. We discuss a few possibilities for how PG 1004+130 could have Compton-thick shielding gas without strong Fe Ka line emission; dilution from jet-linked X-ray emission is one likely explanation. We also discuss the intrinsic X-ray weakness scenario based on a coronal-quenching model relevant to the shielding gas and disk wind of BAL quasars. Motivated by our NuSTAR results, we perform a Chandra stacking analysis with the Large Bright Quasar Survey BAL quasar sample and place statistical constraints upon the fraction of intrinsically X-ray weak BAL quasars; this fraction is likely 17%-40%.

  18. Resonantly excited betatron hard X-Rays from Ionization Injected Electron Beam in a Laser Plasma Accelerator

    OpenAIRE

    K. Huang; Chen, L. M.; Y. F. Li; D.Z. Li; M. Z. Tao; M. Mirzaie; Y. Ma; J. R. Zhao; M. H. Li; M. Chen; Hafz, N.; Sokollik, T.; Sheng, Z. M.; Zhang, J.

    2015-01-01

    A new scheme for bright hard x-ray emission from laser wakefield electron accelerator is reported, where pure nitrogen gas is adopted. Intense Betatron x-ray beams are generated from ionization injected K-shell electrons of nitrogen into the accelerating wave bucket. The x-ray radiation shows synchrotron-like spectrum with total photon yield 8$\\times$10$^8$/shot and $10^8$ over 110keV. In particular, the betatron hard x-ray photon yield is 10 times higher compared to the case of helium gas un...

  19. kHz femtosecond laser-plasma hard X-ray and fast ion source

    Science.gov (United States)

    Thoss, A.; Korn, G.; Richardson, M. C.; Faubel, M.; Stiel, H.; Voigt, U.; Siders, C. W.; Elsaesser, T.

    2002-04-01

    We describe the first demonstration of a new stable, kHz femtosecond laser-plasma source of hard x-ray continuum and Kα emission using a thin liquid metallic jet target. kHz femtosecond x-ray sources will find many applications in time-resolved x-ray diffraction and microscopy studies. As high intensity lasers become more compact and operate at increasingly high repetition-rates, they require a target configuration that is both repeatable from shot-to-shot and is debris-free. We have solved this requirement with the use of a fine (10-30 μm diameter) liquid metal jet target that provides a pristine, unperturbed filament surface at rates >100 kHz. A number of liquid metal targets are considered. We will show hard x-ray spectra recorded from liquid Ga targets that show the generation of the 9.3 keV and 10.3 keV, Kα and Kβ lines superimposed on a multi-keV Bremsstrahlung continuum. This source was generated by a 50fs duration, 1 kHz, 2W, high intensity Ti:Sapphire laser. We will discuss the extension of this source to higher powers and higher repetition rates, providing harder x-ray emission, with the incorporation of pulse-shaping and other techniques to enhance the x-ray conversion efficiency. Using the same liquid target technology, we have also demonstrated the generation of forward-going sub-MeV protons from a 10 μm liquid water target at 1 kHz repetition rates. kHz sources of high energy ions will find many applications in time-resolved particle interaction studies, as well as lead to the efficient generation of short-lived isotopes for use in nuclear medicine and other applications. The protons were detected with CR-39 track detectors both in the forward and backward directions up to energies of ~500 keV. As the intensity of compact high repetition-rate lasers sources increase, we can expect improvements in the energy, conversion efficiency and directionality to occur. The impact of these developments on a number of fields will be discussed. As compact

  20. Compton polarimeter as a focal plane detector for hard X-ray telescope: sensitivity estimation with Geant4 simulations

    Science.gov (United States)

    Chattopadhyay, T.; Vadawale, S. V.; Pendharkar, J.

    2013-04-01

    X-ray polarimetry can be an important tool for investigating various physical processes as well as their geometries at the celestial X-ray sources. However, X-ray polarimetry has not progressed much compared to the spectroscopy, timing and imaging mainly due to the extremely photon-hungry nature of X-ray polarimetry leading to severely limited sensitivity of X-ray polarimeters. The great improvement in sensitivity in spectroscopy and imaging was possible due to focusing X-ray optics which is effective only at the soft X-ray energy range. Similar improvement in sensitivity of polarisation measurement at soft X-ray range is expected in near future with the advent of GEM based photoelectric polarimeters. However, at energies >10 keV, even spectroscopic and imaging sensitivities of X-ray detector are limited due to lack of focusing optics. Thus hard X-ray polarimetry so far has been largely unexplored area. On the other hand, typically the polarisation degree is expected to increase at higher energies as the radiation from non-thermal processes is dominant fraction. So polarisation measurement in hard X-ray can yield significant insights into such processes. With the recent availability of hard X-ray optics (e.g. with upcoming NuSTAR, Astro-H missions) which can focus X-rays from 5 KeV to 80 KeV, sensitivity of X-ray detectors in hard X-ray range is expected to improve significantly. In this context we explore feasibility of a focal plane hard X-ray polarimeter based on Compton scattering having a thin plastic scatterer surrounded by cylindrical array scintillator detectors. We have carried out detailed Geant4 simulation to estimate the modulation factor for 100 % polarized beam as well as polarimetric efficiency of this configuration. We have also validated these results with a semi-analytical approach. Here we present the initial results of polarisation sensitivities of such focal plane Compton polarimeter coupled with the reflection efficiency of present era hard X-ray

  1. Hard X-ray optics simulation using the coherent mode decomposition of Gaussian Schell model

    CERN Document Server

    Hua, Wenqiang; Song, Li; Li, Xiuhong; Wang, Jie

    2013-01-01

    The propagation of hard X ray beam from partially coherent synchrotron source is simulated by using the novel method based on the coherent mode decomposition of Gaussian Schell model and wave front propagation. We investigate how the coherency properties and intensity distributions of the beam are changed by propagation through optical elements. Here, we simulate and analyze the propagation of the partially coherent radiation transmitted through an ideal slit. We present the first simulations for focusing partially coherent synchrotron hard X ray beams using this novel method. And when compared with the traditional method which assumes the source is a totally coherent point source or completely incoherent, this method is proved to be more reasonable and can also demonstrate the coherence properties of the focusing beam. We also simulate the double slit experiment and the simulated results validate the academic analysis.

  2. Multimodality hard-x-ray imaging of a chromosome with nanoscale spatial resolution

    Science.gov (United States)

    Yan, Hanfei; Nazaretski, Evgeny; Lauer, Kenneth; Huang, Xiaojing; Wagner, Ulrich; Rau, Christoph; Yusuf, Mohammed; Robinson, Ian; Kalbfleisch, Sebastian; Li, Li; Bouet, Nathalie; Zhou, Juan; Conley, Ray; Chu, Yong S.

    2016-02-01

    We developed a scanning hard x-ray microscope using a new class of x-ray nano-focusing optic called a multilayer Laue lens and imaged a chromosome with nanoscale spatial resolution. The combination of the hard x-ray’s superior penetration power, high sensitivity to elemental composition, high spatial-resolution and quantitative analysis creates a unique tool with capabilities that other microscopy techniques cannot provide. Using this microscope, we simultaneously obtained absorption-, phase-, and fluorescence-contrast images of Pt-stained human chromosome samples. The high spatial-resolution of the microscope and its multi-modality imaging capabilities enabled us to observe the internal ultra-structures of a thick chromosome without sectioning it.

  3. Hard X-ray Variability of the Brightest Swift/BAT AGN

    CERN Document Server

    Ricci, Claudio; Soldi, Simona; Courvoisier, Thierry J -L

    2011-01-01

    Variability is one of the hallmarks of Active Galactic Nuclei. The Burst Alert Telescope onboard of Swift, with its homogeneous coverage of the sky is a formidable tool to study variability at hard X-rays. We present here the analysis of the 1-month binned Swift/BAT lightcurves of the 20 brightest Active Galactic Nuclei in the hard X-ray sky. The sample consists of 2 blazars, 3 radio galaxies, 6 Seyfert 1/1.5s, 8 Seyfert 2s and 1 Narrow Line Seyfert 1. We found that all the objects show variability, and most of them have a value of the fractional root mean squared variability amplitude of Fvar \\sim 0.2 - 0.3. We did not find any significant correlation of Fvar with the column density or the luminosity in our sample.

  4. Radio and hard X-ray signatures of flare accelerated electrons

    Science.gov (United States)

    Vilmer, N. R.

    2003-12-01

    While imaging and spectral radio observations in the decimetric-dekametric domain provide signatures of non-thermal electrons in the middle and upper corona, hard X-rays as well as microwaves trace flare accelerated electrons in the low corona and the chromosphere. Radio observations combined with hard X-ray observations thus allow to analyse the signature of energetic electrons in a whole range of coronal heights. We shall present here the results of multiwavelength studies primarily based on the analysis of HXR and decimetric/metric spatially resolved observations from RHESSI and the Nançay Radioheliograph. We shall outline how these combined observations provide information on the magnetic structures at different spatial scales in which energetic electrons are accelerated and injected as well as on the link between the production of energetic electrons interacting at the Sun and the injection of escaping electrons giving rise to the radio emissions at the lowest frequencies.

  5. Development of thermally formed glass optics for astronomical hard X-ray telescopes

    DEFF Research Database (Denmark)

    Craig, W.W.; Hailey, C.J.; Jimenez-Garate, M.;

    2000-01-01

    . The recent development of depth-graded multilayer coatings has made the design of telescopes for this bandpass practical, however the ability to manufacture inexpensive substrates with appropriate surface quality and figure to achieve sub-arcminute performance has remained an elusive goal. In this paper, we......The next major observational advance in hard X-ray/soft gamma-ray astrophysics will come with the implementation of telescopes capable of focusing 10-200 keV radiation. Focusing allows high signal-to-noise imaging and spectroscopic observations of many sources in this band for the first time...... report on new, thermally-formed glass micro-sheet optics capable of meeting the requirements of the next-generation of astronomical hard X-ray telescopes....

  6. Point source detection performance of Hard X-ray Modulation Telescope imaging observation

    CERN Document Server

    Huo, Zhuoxi; Li, Xiaobo; Zhou, Jianfeng

    2015-01-01

    The Hard X-ray Modulation Telescope (HXMT) will perform an all-sky survey in hard X-ray band as well as deep imaging of a series of small sky regions. We expect various compact objects to be detected in these imaging observations. Point source detection performance of HXMT imaging observation depends not only on the instrument but also on its data analysis since images are reconstructed from HXMT observed data with numeric methods. Denoising technique plays an import part in HXMT imaging data analysis pipeline alongside with demodulation and source detection. In this paper we have implemented several methods for denoising HXMT data and evaluated the point source detection performances in terms of sensitivities and location accuracies. The results show that direct demodulation with 1-fold cross correlation should be the default reconstruction and regularization methods, although both sensitivity and location accuracy could be further imporved by selecting and tuning numerical methods in data analysis of HXMT i...

  7. A practical method to generate brilliant hard x-rays with a tabletop electron storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, H. [Ritsumeikan Univ., Shiga (Japan); Amano, D.; Miyade, H. [Sumitomo Heavy Industries, Ltd., Tanashi-City (Japan)

    1995-12-31

    With electron storage rings not only synchrotron radiation(SR) but also bremsstrahlung(BS) from a thin target placed in the electron orbit are mechanisms to generate brilliant x-ray beams. The calculated brilliance of BS with a 50 MeV storage ring, which is nearly 10{sup 13} photons/s, mrad{sup 2}, mm{sup 2}, 0.1% band width for 100 keV x-rays, exceeds that of SR from a 1 GeV storage ring. This photon energy spectrum is almost constant and extend up to the electron energy. The reasons for this high brilliance with this new radiation scheme is that the electron beams penetrating the thin target are utilized repeatedly, the narrow angular divergence of BS is determined by the kinematics of relativistic electron as same as SR, and the x-ray source size of the order of 1 {mu}m is determined by the size of thin target instead of electron beam sizes. Continuous injection of electron beam to the storage ring at full energy is the way to keep high and constant beam current. Peak current and repetition rate determine x-ray out put power. Note that the power of x-ray beam is also provided from a RF cavity of the storage ring. In this paper we will report some experimental results and discuss further application on a coherent bremsstrahlung generated from a set of stacked foils placed in the electron orbit of the ring. Resulting from these investigations the photon storage ring which is based on a 50 MeV exact circular electron storage ring could provide wide range of coherent and incoherent radiations from far infrared to hard x-ray in a practical amount of radiation power.

  8. HEAO 1 hard X-ray observation of clusters of galaxies and intracluster magnetic fields

    Science.gov (United States)

    Rephaeli, Yoel; Gruber, D. E.

    1988-01-01

    The results of HEAO 1 hard X-ray measurements of three clusters of galaxies, Abell 401, Abell 2255, and Abell 2256 are reported. Nonthermal components were not detected above the level of 10 to the -5th photons/sq cm/s/keV. Comparison of the flux upper limits with theoretical predictions yields lower limits of about 10 to the -7th gauss on the mean value of the intracluster magnetic fields in the central regions of these clusters.

  9. Self-standing quasi-mosaic crystals for focusing hard X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Camattari, Riccardo; Guidi, Vincenzo; Bellucci, Valerio; Neri, Ilaria; Frontera, Filippo [Department of Physics and Earth Science, University of Ferrara, Via Saragat 1/c, 44122 Ferrara (Italy); CNR-IDASC SENSOR Lab. (Italy); Jentschel, Michael [Institut Laue Langevin, F-38042 Grenoble Cedex (France)

    2013-05-15

    A quasi mosaic bent crystal for high-resolution diffraction of X and {gamma} rays has been realized. A net curvature was imprinted to the crystal thanks to a series of superficial grooves to keep the curvature without external devices. The crystal highlights very high diffraction efficiency due to quasi mosaic curvature. Quasi mosaic crystals of this kind are proposed for the realization of a high-resolution focusing Laue lens for hard X-rays.

  10. Optimization of Reconstructed Quality of Hard X-ray Phase Micro-Tomography

    OpenAIRE

    Liu, Huiqiang; Wu, Xizeng; Xiao, Tiqiao

    2015-01-01

    For the applications of hard X-ray Propagation-based Phase-contrast Computed micro-Tomography (PPCT) in high-resolution biological research, both the high spatial resolution and high contrast-to-noise ratio are simultaneously required for tiny structural discrimination and characterization. Most existing micro-CT techniques to improve image quality are limited by high cost, physical limitations, and complexity of the experimental hardware and setup. In this work a novel PPCT technique, which ...

  11. AGN in the Swift/BAT and INTEGRAL Hard X-ray Surveys

    Science.gov (United States)

    Beckmann, Volker; Tueller, Jack; Baumgartner, Wayne; Markwardt, Craig; Mushotzky, Richard; Skinner, Gerry

    2008-01-01

    Two hard X-ray surveys are in progress at this time. They provide a unique new window on compact objects and black holes. I will discuss how these two surveys complement each other and the potential for improved coordination that could yield significant near term results in both sensitivity and time coverage. I will pay particular attention to the discovery of faint sources including new results from the 36 month survey from Swift/Burst Alert Telescope (BAT).

  12. Weak Hard X-ray Emission from Broad Absorption Line Quasars: Evidence for Intrinsic X-ray Weakness

    CERN Document Server

    Luo, B; Alexander, D M; Stern, D; Teng, S H; Arévalo, P; Bauer, F E; Boggs, S E; Christensen, F E; Comastri, A; Craig, W W; Farrah, D; Gandhi, P; Hailey, C J; Harrison, F A; Koss, M; Ogle, P; Puccetti, S; Saez, C; Scott, A E; Walton, D J; Zhang, W W

    2014-01-01

    We report NuSTAR observations of a sample of six X-ray weak broad absorption line (BAL) quasars. These targets, at z=0.148-1.223, are among the optically brightest and most luminous BAL quasars known at z330 times weaker than expected for typical quasars. Our results from a pilot NuSTAR study of two low-redshift BAL quasars, a Chandra stacking analysis of a sample of high-redshift BAL quasars, and a NuSTAR spectral analysis of the local BAL quasar Mrk 231 have already suggested the existence of intrinsically X-ray weak BAL quasars, i.e., quasars not emitting X-rays at the level expected from their optical/UV emission. The aim of the current program is to extend the search for such extraordinary objects. Three of the six new targets are weakly detected by NuSTAR with 33%) of intrinsically X-ray weak objects among the BAL quasars with significantly weak <10 keV emission. We suggest that intrinsically X-ray weak quasars might be preferentially observed as BAL quasars.

  13. X-Ray Ccds for Space Applications: Calibration, Radiation Hardness, and Use for Measuring the Spectrum of the Cosmic X-Ray Background

    Science.gov (United States)

    Gendreau, Keith Charles

    1995-01-01

    This thesis has two distinct components. One concerns the physics of the high energy resolution X-ray charge coupled devices (CCD) detectors used to measure the cosmic X-ray background (XRB) spectrum. The other involves the measurements and analysis of the XRB spectrum and instrumental background with these detectors on board the advanced satellite for cosmology and astrophysics (ASCA). The XRB has a soft component and a hard component divided at ~2 keV. The hard component is extremely isotropic, suggesting a cosmological origin. The soft component is extremely anisotropic. A galactic component most likely dominates the soft band with X-ray line emission due to a hot plasma surrounding the solar system. ASCA is one of the first of a class of missions designed to overlap the hard and soft X-ray bands. The X-ray CCD's energy resolution allows us to spectrally separate the galactic and cosmological components. Also, the resolution offers the ability to test several specific cosmological models which would make up the XRB. I have concentrated on models for the XRB origin which include active galactic nuclei (AGN) as principal components. I use ASCA data to put spectral constraints on the AGN synthesis model for the XRB. The instrumental portion of this thesis concerns the development and calibration of the X-ray CCDs. I designed, built and operated an X-ray calibration facility for these detectors. It makes use of a reflection grating spectrometer to measure absolute detection efficiency, characteristic absorption edge strengths, and spectral redistribution in the CCD response function. Part of my thesis research includes a study of radiation damage mechanisms in CCDs. This work revealed radiation damage-induced degradation in the spectral response to X-rays. It also uncovered systematic effects which affect both data analysis and CCD design. I have developed a model involving trap energy levels in the CCD band gap structure. These traps reduce the efficiency in which

  14. Starburst Galaxies: Hard X-ray spectra and contribution to the diffuse background

    Science.gov (United States)

    Gruber, Duane E.

    1993-01-01

    During the period of this grant two main tasks were performed: a determination of a selection criterion for starburst galaxies most likely to emit X-rays, and performance of a pilot study of the X-ray emission from nine such systems. Starburst galaxies may be expected to emit flat-spectrum X-ray at energies above 10 keV resulting from the various remnants of the short-lived massive stars which characterize the starburst. The investigation to determine the optimum sample resulted in a change from an X-ray selected (HEAO-2) sample to infrared selection based on the IRAS catalogue. A much broader sample thereby available for study, and selection could be limited to only the nearest objects and still obtain a reasonably large sample. A sample of 99 of the brightest infrared starburst galaxies was settled on for the X-ray survey. For a set of practical size, this was then reduced to a subset of 53, based on luminosity and nearness. X-ray emission from these objects was individually measured from the UCSD HEAO-1 all-sky survey in four energy bands between 13 keV to 160 keV. This data base consists of about 20 optical disk volumes. Net significance for the result was roughly two sigma, and a very hard spectral shape is indicated for the net spectrum of the surveyed galaxies. With the possibility of detection of the class, it was then felt worthwhile to examine fluxes from these sources in other archival data. This was performed with the HEAO-1 A2 data and the HEAO-2 (EINSTEIN) main archive and slew survey. Positive results were also obtained for the sample, but again at weak significance. With three independent measures of weak X-ray fluxes from nearby starburst galaxies, we wrote a letter to the Astrophysical Journal (enclosed) discussing these results and their likely significance, in particular, for the contribution to the cosmic diffuse x-ray background, perhaps as much as 25 percent.

  15. Eta Carinae's Hard X-ray Tail Measured with XMM-Newton and NuSTAR

    Science.gov (United States)

    Hamaguchi, Kenji; Corcoran, Michael F.; Sharma, Neetika; Gull, Theodore R.; Takahashi, Hiromitsu; Grefenstette, Brian; Yuasa, Takayuki; Stuhlinger, Martin; Russell, Christopher Michael Post; Moffat, Anthony F. J.; Madura, Thomas; Richardson, Noel; Groh, Jose; Pittard, Julian; Owocki, Stan

    2016-04-01

    Massive binary stellar systems drive shock plasma heating via the collision of winds from two stars (wind-wind collision: WWC). With typical (pre-shock) wind speeds of ≥1000 km s-1, temperatures can reach as high as several tens of millions of Kelvin. X-ray emission from these stable shocks provides important tests of shock physics. While the spectrum below 10 keV is complicated by discrete line emission and absorption components, the X-ray spectrum above 10 keV is relatively simple. This high-energy emission therefore provides important clues on the condition of the maximum thermalized plasma where the winds collide head-on, while also providing important information about particle acceleration through the shock.We obtained two coordinated X-ray observations of the super massive binary system η Carinae with XMM-Newton and NuSTAR, during the elevated X-ray flux state and just before the X-ray minimum flux state around the periastron passage in the summer of 2014. These NuSTAR observations clearly detected X-ray emission associated with η Car extending up to ~50 keV for the first time. The NuSTAR spectrum above 10 keV can be fit with the bremsstrahlung tail from a kT ~6 keV plasma, about 2 keV higher than those measured from the iron K emission line complex. This result may suggest that the companion star's pre-shock wind velocity is underestimated. The NuSTAR observation near the X-ray minimum state showed a gradual decline in the >5 keV emission by 40% in a day. The extreme absorption to the hardest emission component (NH~1e24 cm-2) suggests increased obscuration of the WWC X-ray emission by the thick primary stellar wind prior to superior conjunction. Neither observation detected the power-law component in the extremely hard band that INTEGRAL and Suzaku observed prior to 2011. If the non-detection by NuSTAR is caused by absorption, the power-law source must be small and located very near the WWC apex. Alternatively, it may be that the power-law source is not

  16. A Focused, Hard X-ray Look at Arp 299 with NuSTAR

    CERN Document Server

    Ptak, A; Zezas, A; Lehmer, B; Yukita, M; Wik, D; Antoniou, V; Argo, M K; Ballo, L; Bechtol, K; Boggs, S; Della Ceca, R; Christensen, F E; Craig, W W; Hailey, C J; Harrison, F A; Krivonos, R; Maccarone, T J; Stern, D; Tatum, M; Venters, T; Zhang, W W

    2014-01-01

    We report on simultaneous observations of the local starburst system Arp 299 with NuSTAR and Chandra, which provides the first resolved images of this galaxy up to energies of ~ 45 keV. Fitting the 3-40 keV spectrum reveals a column density of $N_{\\rm H}$ ~ 4 x10^{24} cm^{-2}, characteristic of a Compton-thick AGN, and a 10-30 keV luminosity of 1.2x 10^{43} ergs s^{-1}. The hard X-rays detected by NuSTAR above 10 keV are centered on the western nucleus, Arp 299-B, which previous X-ray observations have shown to be the primary source of neutral Fe-K emission. Other X-ray sources, including Arp 299-A, the eastern nucleus which is also thought to harbor an AGN, as well as X-ray binaries, contribute $\\lesssim 10%$ to the 10-20 keV emission from the Arp 299 system. The lack of significant emission above 10 keV other than that attributed to Arp 299-B suggests that: a) any AGN in Arp 299-A must be heavily obscured ($N_{\\rm H}$ > 10^{24} cm^{-2}) or have a much lower luminosity than Arp 299-B and b) the extranuclear ...

  17. Small hard X-ray source using X-band linac

    CERN Document Server

    Uesaka, M; Iijima, H; Tsuchihashi, K; Urakawa, J; Higo, T; Akemoto, M; Hayano, H

    2002-01-01

    For application to dynamic angiographies and life science, small hard X-ray source by laser electron beam collision using X-band linac has been developed. The outline of X-band linac system and the X-ray intensity are discussed. The X-ray intensity of some combinations of laser and electron sources was evaluated by numerical calculations. Four kinds of combinations such as photo-cathode RF-gun + short pulse laser, thermionic-cathode RF-gun + Q-switch Nd:YAG laser, multi-bunch photo-cathode RF-gun + laser accumulator and 200 MeV electron storage ring + laser accumulator were investigated. X-band RF-gun is being used and S-band Mg photo-cathode RF-gun is studied. The X-ray intensity of the thermionic-cathode RF-gun + Q-switch Nd:YAG laser is 10 sup 7 phons/s(total) at 50 keV. This value can be used for structure analysis of protein. (S.Y.)

  18. Resonantly Enhanced Betatron Hard X-rays from Ionization Injected Electrons in a Laser Plasma Accelerator.

    Science.gov (United States)

    Huang, K; Li, Y F; Li, D Z; Chen, L M; Tao, M Z; Ma, Y; Zhao, J R; Li, M H; Chen, M; Mirzaie, M; Hafz, N; Sokollik, T; Sheng, Z M; Zhang, J

    2016-01-01

    Ultrafast betatron x-ray emission from electron oscillations in laser wakefield acceleration (LWFA) has been widely investigated as a promising source. Betatron x-rays are usually produced via self-injected electron beams, which are not controllable and are not optimized for x-ray yields. Here, we present a new method for bright hard x-ray emission via ionization injection from the K-shell electrons of nitrogen into the accelerating bucket. A total photon yield of 8 × 10(8)/shot and 10(8 )photons with energy greater than 110 keV is obtained. The yield is 10 times higher than that achieved with self-injection mode in helium under similar laser parameters. The simulation suggests that ionization-injected electrons are quickly accelerated to the driving laser region and are subsequently driven into betatron resonance. The present scheme enables the single-stage betatron radiation from LWFA to be extended to bright γ-ray radiation, which is beyond the capability of 3(rd) generation synchrotrons. PMID:27273170

  19. Resonantly Enhanced Betatron Hard X-rays from Ionization Injected Electrons in a Laser Plasma Accelerator

    Science.gov (United States)

    Huang, K.; Li, Y. F.; Li, D. Z.; Chen, L. M.; Tao, M. Z.; Ma, Y.; Zhao, J. R.; Li, M. H.; Chen, M.; Mirzaie, M.; Hafz, N.; Sokollik, T.; Sheng, Z. M.; Zhang, J.

    2016-06-01

    Ultrafast betatron x-ray emission from electron oscillations in laser wakefield acceleration (LWFA) has been widely investigated as a promising source. Betatron x-rays are usually produced via self-injected electron beams, which are not controllable and are not optimized for x-ray yields. Here, we present a new method for bright hard x-ray emission via ionization injection from the K-shell electrons of nitrogen into the accelerating bucket. A total photon yield of 8 × 108/shot and 108 photons with energy greater than 110 keV is obtained. The yield is 10 times higher than that achieved with self-injection mode in helium under similar laser parameters. The simulation suggests that ionization-injected electrons are quickly accelerated to the driving laser region and are subsequently driven into betatron resonance. The present scheme enables the single-stage betatron radiation from LWFA to be extended to bright γ-ray radiation, which is beyond the capability of 3rd generation synchrotrons.

  20. PLEIADES: High Peak Brightness, Subpicosecond Thomson Hard-X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Kuba, J; Anderson, S G; Barty, C J; Betts, S M; Booth, R; Brown, W J; Crane, J K; Cross, R R; Fittinghoff, D N; Gibson, D J; Harteman, F V; Le Sage, G P; Rosenzweig, J B; Tremaine, A M; Springer, P T

    2003-12-15

    The Picosecond Laser-Electron Inter-Action for the Dynamic Evaluation of Structures (PLEIADES) facility, is a unique, novel, tunable (10-200 keV), ultrafast (ps-fs), hard x-ray source that greatly extends the parameter range reached by existing 3rd generation sources, both in terms of x-ray energy range, pulse duration, and peak brightness at high energies. First light was observed at 70 keV early in 2003, and the experimental data agrees with 3D codes developed at LLNL. The x-rays are generated by the interaction of a 50 fs Fourier-transform-limited laser pulse produced by the TW-class FALCON CPA laser and a highly focused, relativistic (20-100 MeV), high brightness (1 nC, 0.3-5 ps, 5 mm.mrad, 0.2% energy spread) photo-electron bunch. The resulting x-ray brightness is expected to exceed 10{sup 20} ph/mm{sup 2}/s/mrad{sup 2}/0.1% BW. The beam is well-collimated (10 mrad divergence over the full spectrum, 1 mrad for a single color), and the source is a unique tool for time-resolved dynamic measurements in matter, including high-Z materials.

  1. Optimising hard X-ray generation from laser-produced plasmas

    International Nuclear Information System (INIS)

    The aim of this work is to increase the X-ray yield for a laser produced plasma by optimising the focusing conditions and temporal shape of the laser pulses. The focusing conditions are improved by introducing a control system that secures the laser target surface to exact focus within a range of a few micrometers, allowing continuously high laser intensity for plasma generation. The temporal shape of the laser pulses is changed by introducing a saturable absorber in the laser beam. The laser produces a substantial pre-pulse that heats and expands the target material prior to main pulse arrival. The saturable absorber can increase the main pulse/pre-pulse ratio of the laser pulse up to four orders of magnitude and consequently reduce expansion of the target material before the main pulse. The belief is that an increase in target density at the time of main pulse arrival will change the energy distribution of the X-rays, towards a more efficient X-ray production in the hard X-ray region. This report and the work connected to it, includes the preliminary measurements and results for these improvements. 17 refs

  2. Generalised Cornu spirals: an experimental study using hard x-rays.

    Science.gov (United States)

    Werdiger, Freda; Kitchen, Marcus J; Paganin, David M

    2016-05-16

    The Cornu spiral is a graphical aid that has been used historically to evaluate Fresnel integrals. It is also the Argand-plane mapping of a monochromatic complex scalar plane wave diffracted by a hard edge. We have successfully reconstructed a Cornu spiral due to diffraction of hard x-rays from a piece of Kapton tape. Additionally, we have explored the generalisation of the Cornu spiral by observing the Argand-plane mapping of complex scalar electromagnetic fields diffracted by a cylinder and a sphere embedded within a cylinder. PMID:27409884

  3. The HEXIT-SAT and SIMBOL-X Hard X-ray missions

    Science.gov (United States)

    Pareschi, G.; HEXIT-SAT and SIMBOL-X Collaborations

    HEXIT-SAT and SIMBOL-X are two astronomy mission concepts based on hard X-ray (E ge 10 keV) focusing optics, with several Italian researchers involved in the design and definition of both satellites. HEXIT-SAT is based on 4 optics modules with 8 m focal lenghth, each formed by a number of confocal multilayer-coated Wolter I shells, the maximum diameter being 35 cm. Due to their broad-band reflection response, multilayer mirrors allow us to focus X-ray photons with energies beyond 10 keV up to about 100 keV, a region where just direct-view detectors have been operated so far. The SIMBOL-X project instead relies on a single-module optics with 60 cm diameter, and it is characterized by a very large focal length (30 m), achieved by means of two separate spacecrafts (one for the mirror module, the other for the detector unit) in a formation-flight configuration. At the moment the reflecting coating assumed for the mirrors is a Pt single layer film that, due to the very small reflection angles involved, is able to guarantee a high effective area for hard X-rays up to 50 keV. The use of multilayer mirrors to further extend the reflection band is currently being considered. HEXIT-SAT and SIMBOL-X are both characterized by an unprecedented flux sensitivity (with a gain of several hundreds compared to the hard X-ray missions already flown) and a much better angular resolution. In this paper a short review of the main features of both missions is reported.

  4. Electron trapping in evolving coronal structures during a large gradual hard X-ray/radio burst

    Science.gov (United States)

    Bruggmann, G.; Vilmer, N.; Klein, K.-L.; Kane, S. R.

    1994-01-01

    Gradual hard X-ray/radio bursts are characterized by their long duration, smooth time profile, time delays between peaks at different hard X-ray energies and microwaves, and radiation from extended sources in the low and middle corona. Their characteristic properties have been ascribed to the dynamic evolution of the accelerated electrons in coronal magnetic traps or to the separate acceleration of high-energy electrons in a 'second step' process. The information available so far was drawn from quality considerations of time profiles or even only from the common occurrence of emissions in different spectral ranges. This paper presents model computations of the temporal evolution of hard X-ray and microwave spectra, together with a qualitative discussion of radio lightcurves over a wide spectral range, and metric imaging observations. The basis hypothesis investigated is that the peculiar 'gradual' features can be related to the dynamical evolution of electrons injected over an extended time interval in a coronal trap, with electrons up to relativistic energies being injected simultaneously. The analyzed event (26 April. 1981) is particularly challenging to this hypothesis because of the long time delays between peaks at different X-ray energies and microwave frequencies. The observations are shown to be consistent with the hypothesis, provided that the electrons lose their energy by Coulomb collisions and possibly betatron deceleration. The access of the electrons to different coronal structures varies in the course of the event. The evolution and likely destabilization of part of the coronal plasma-magnetic field configuration is of crucial influence in determining the access to these structures and possibly the dynamical evolution of the trapped electrons through betatron deceleration in the late phase of the event.

  5. NuSTAR detection of 4s Hard X-ray Lags from the Accreting Pulsar GS 0834-430

    DEFF Research Database (Denmark)

    Bachetti, Matteo; Miyasaka, Hiromasa; Harrison, Fiona;

    2014-01-01

    The NuSTAR hard X-ray telescope observed the transient Be/X-ray binary GS 0834􀀀430 during its 2012 outburst. The source is detected between 3 – 79 keV with high statistical significance, and we were able to perform very accurate spectral and timing analysis. The phase-averaged spectrum i...

  6. Hard X-ray Spectrum of Mkn 421 during the Active Phase

    Indian Academy of Sciences (India)

    R. K. Manchanda

    2001-06-01

    Spectral measurement of Mkn 421 were made in the hard X-ray energy band of 20–200 keV using a high sensitivity, large area scintillation counter telescope on November 21, 2000 and these coincided with the onset of an active X-ray phase as seen in the ASM counting rates on board RXTE. The observed spectrum can not be fitted to a single power law similar to the PDS data of BeppoSAX. The data can be fitted both by a two component power-law function or a combination of an exponential function with a power law component at the high energies above 80 keV. We identify these components with those arising from the synchrotron self compton and the high energy power-law tail arising from the upgrading of the thermal photons due to multiple Compton scattering a la Cyg X-1. A comparison with the earlier data clearly suggests a spectral variability in the hard X-ray spectrum of the source. We propose a continuously flaring geometry for the source as the underlying mechanism for energy release.

  7. Imaging of cochlear tissue with a grating interferometer and hard X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Richter, Claus-Peter; Shintani-Smith, Stephanie; Fishman, Andrew; David, Christian; Robinson, Ian; Rau, Christoph; (PSI); (NWU); (UCL)

    2010-01-28

    This article addresses an important current development in medical and biological imaging: the possibility of imaging soft tissue at resolutions in the micron range using hard X-rays. Challenging environments, including the cochlea, require the imaging of soft tissue structure surrounded by bone. We demonstrate that cochlear soft tissue structures can be imaged with hard X-ray phase contrast. Furthermore, we show that only a thin slice of the tissue is required to introduce a large phase shift. It is likely that the phase contrast image of the soft tissue structures is sufficient to image the structures even if surrounded by bone. For the present set of experiments, structures with low-absorption contrast have been visualized using in-line phase contrast imaging and a grating interferometer. The experiments have been performed at the Advanced Photon Source at Argonne National Laboratories, a third generation source of synchrotron radiation. The source provides highly coherent X-ray radiation with high-photon flux (>10{sup 12} photons/s) at high-photon energies (5-70 keV). Radiographic and light microscopy images of the gerbil cochlear slice samples were compared. It has been determined that a 20-{micro}m thick tissue slice induces a phase shift between 1/3{pi} and 2/3{pi}.

  8. Hard X-ray emitting black hole fed by accretion of low angular momentum matter

    CERN Document Server

    Igumenshchev, I V; Abramowicz, M A; Igumenshchev, Igor V.; Illarionov, Andrei F.; Abramowicz, Marek Artur

    1999-01-01

    Observed spectra of Active Galactic Nuclei (AGN) and luminous X-ray binaries in our Galaxy suggest that both hot (~10^9 K) and cold (~10^6 K) plasma components exist close to the central accreting black hole. Hard X-ray component of the spectra is usually explained by Compton upscattering of optical/UV photons from optically thick cold plasma by hot electrons. Observations also indicate that some of these objects are quite efficient in converting gravitational energy of accretion matter into radiation. Existing theoretical models have difficulties in explaining the two plasma components and high intensity of hard X-rays. Most of the models assume that the hot component emerges from the cold one due to some kind of instability, but no one offers a satisfactory physical explanation for this. Here we propose a solution to these difficulties that reverses what was imagined previously: in our model the hot component forms first and afterward it cools down to form the cold component. In our model, accretion flow ha...

  9. HEXTE Detections of Hard X-Ray Tails in Sco X-1

    CERN Document Server

    D'Amico, F; Rothschild, R E; Gruber, D

    2000-01-01

    We report the detection of a non-thermal hard X-ray component from Sco X-1 based upon the analysis of 20-220 keV spectra obtained with the HEXTE experiment onboard the RXTE satellite. We find that the addition of a power-law component to a thermal bremsstrahlung model is required to achieve a good fit in 5 of 16 observations analyzed. Using PCA data we were able to track the movement of the source along the Z diagram, and we found that the presence of the hard X-ray tail is not confined to a specific Z position. However, we do observe an indication that the power law index hardens with increasing mass accretion rate, as indicated from the position on the Z diagram. We find that the derived non-thermal luminosities are about 10% of that derived for the brightest of the atoll sources. These observations provide firm evidence for non-thermal X-ray activity in a Z source.

  10. Observed energy dependence of Fano factor in silicon at hard X-ray energies

    International Nuclear Information System (INIS)

    An experimental evaluation of the Fano factor F in silicon at hard X-ray energies (5.9-136.5 keV) has been performed by means of a low-noise, high charge collection efficiency silicon drift detector with on-chip electronics. A dependence of F from the detector temperature as well as from the energy of the X-ray photons has been found. Assuming a pair creation energy equal to 3.64 eV, at +20 deg. C the F factor was observed to vary from 0.124±0.006 at 5.9 keV up to 0.159±0.002 at 122 keV. At -35 deg. C, the change of F with respect to the photon energy was less remarkable but nevertheless statistically significant, from 0.123±0.002 at 5.9 keV up to 0.134±0.001 at 122 keV. To our knowledge, the present results represent the first experimental evidence of an energy dependence of the Fano factor in silicon at hard X-ray energies

  11. Observed energy dependence of Fano factor in silicon at hard X-ray energies

    CERN Document Server

    Perotti, F

    1999-01-01

    An experimental evaluation of the Fano factor F in silicon at hard X-ray energies (5.9-136.5 keV) has been performed by means of a low-noise, high charge collection efficiency silicon drift detector with on-chip electronics. A dependence of F from the detector temperature as well as from the energy of the X-ray photons has been found. Assuming a pair creation energy equal to 3.64 eV, at +20 deg. C the F factor was observed to vary from 0.124+-0.006 at 5.9 keV up to 0.159+-0.002 at 122 keV. At -35 deg. C, the change of F with respect to the photon energy was less remarkable but nevertheless statistically significant, from 0.123+-0.002 at 5.9 keV up to 0.134+-0.001 at 122 keV. To our knowledge, the present results represent the first experimental evidence of an energy dependence of the Fano factor in silicon at hard X-ray energies.

  12. Gamma-ray emitting radio galaxies at hard X-rays: Seyfert core or jet emission?

    CERN Document Server

    Beckmann, V; Mattana, F; Saez, D; Soldi, S

    2013-01-01

    A number of radio galaxies has been detected by Fermi/LAT in the gamma-ray domain. In some cases, like Cen A and M 87, these objects have been seen even in the TeV range by Cherenkov telescopes. Whereas the gamma-ray emission is likely to be connected with the non-thermal jet emission, dominating also the radio band, the situation is less clear at hard X-rays. While the smoothly curved continuum emission and the overall spectral energy distribution indicate a non-thermal emission, other features such as the iron line emission and the low variability appear to be rather of Seyfert type, i.e. created in the accretion disk and corona around the central black hole. We investigate several prominent cases using combined X-ray and gamma-ray data in order to constrain the possible contributions of the jet and the accretion disk to the overall spectral energy distribution in radio galaxies. Among the three sources we study, three different origins of the hard X-ray flux can be identified. The emission can be purely no...

  13. The column density distribution of hard X-ray radio galaxies

    CERN Document Server

    Panessa, F; Landi, R; Bazzano, A; Dallacasa, D; La Franca, F; Malizia, A; Venturi, T; Ubertini, P

    2016-01-01

    In order to investigate the role of absorption in AGN with jets, we have studied the column density distribution of a hard X-ray selected sample of radio galaxies, derived from the INTEGRAL/IBIS and Swift/BAT AGN catalogues (~7-10% of the total AGN population). The 64 radio galaxies have a typical FRII radio morphology and are characterized by high 20-100 keV luminosities (from 10^42 to 10^46 erg/s) and high Eddington ratios (Log L_{Bol}/L_{Edd} typically larger than ~0.01). The observed fraction of absorbed AGN (N_{H} > 10^{22} cm^{-2}) is around 40% among the total sample, and ~75% among type 2 AGN. The majority of obscured AGN are narrow line objects, while unobscured AGN are broad line objects, obeying to the zeroth-order predictions of unified models. A significant anti-correlation between the radio core dominance parameter and the X-ray column density is found. The observed fraction of Compton thick AGN is ~2-3%, in comparison with the 5-7% found in radio-quiet hard X-ray selected AGN. We have estimated...

  14. Hard x-ray transmission crystal spectrometer at the OMEGA-EP laser facilitya)

    Science.gov (United States)

    Seely, J. F.; Szabo, C. I.; Feldman, U.; Hudson, L. T.; Henins, A.; Audebert, P.; Brambrink, E.

    2010-10-01

    The transmission crystal spectrometer (TCS) is approved for taking data at the OMEGA-EP laser facility since 2009 and will be available for the OMEGA target chamber in 2010. TCS utilizes a Cauchois type cylindrically bent transmission crystal geometry with a source to crystal distance of 600 mm. Spectral images are recorded by image plates in four positions, one IP on the Rowland circle and three others at 200, 400, and 600 mm beyond the Rowland circle. An earlier version of TCS was used at LULI on experiments that determined the x-ray source size from spectral line broadening on one IP positioned behind the Rowland circle. TCS has recorded numerous backlighter spectra at EP for point projection radiography and for source size measurements. Hard x-ray source size can be determined from the source broadening of both K shell emission lines and from K absorption edges in the bremsstrahlung continuum, the latter being a new way to measure the spatial extent of the hard x-ray bremsstrahlung continuum.

  15. Hard x-ray transmission crystal spectrometer at the OMEGA-EP laser facility.

    Science.gov (United States)

    Seely, J F; Szabo, C I; Feldman, U; Hudson, L T; Henins, A; Audebert, P; Brambrink, E

    2010-10-01

    The transmission crystal spectrometer (TCS) is approved for taking data at the OMEGA-EP laser facility since 2009 and will be available for the OMEGA target chamber in 2010. TCS utilizes a Cauchois type cylindrically bent transmission crystal geometry with a source to crystal distance of 600 mm. Spectral images are recorded by image plates in four positions, one IP on the Rowland circle and three others at 200, 400, and 600 mm beyond the Rowland circle. An earlier version of TCS was used at LULI on experiments that determined the x-ray source size from spectral line broadening on one IP positioned behind the Rowland circle. TCS has recorded numerous backlighter spectra at EP for point projection radiography and for source size measurements. Hard x-ray source size can be determined from the source broadening of both K shell emission lines and from K absorption edges in the bremsstrahlung continuum, the latter being a new way to measure the spatial extent of the hard x-ray bremsstrahlung continuum. PMID:21034000

  16. Long-Term Variability of AGN at Hard X-Rays

    Science.gov (United States)

    Soldi, S.; Beckmann, V.; Baumgartner W. H.; Ponti, G.; Shrader, C. R.; Lubinski, P.; Krimm, H. A.; Mattana, F.; Tueller, J.

    2013-01-01

    Variability at all observed wavelengths is a distinctive property of active galactic nuclei (AGN). Hard X-rays provide us with a view of the innermost regions of AGN, mostly unbiased by absorption along the line of sight. Characterizing the intrinsic hard X-ray variability of a large AGN sample and comparing it to the results obtained at lower X-ray energies can significantly contribute to our understanding of the mechanisms underlying the high-energy radiation. Methods. Swift/BAT provides us with the unique opportunity to follow, on time scales of days to years and with a regular sampling, the 14-195 keV emission of the largest AGN sample available up to date for this kind of investigation. As a continuation of an early work on the first 9 months of BAT data, we study the amplitude of the variations, and their dependence on sub-class and on energy, for a sample of 110 radio quiet and radio loud AGN selected from the BAT 58-month survey. About 80 of the AGN in the sample are found to exhibit significant variability on months to years time scales, radio loud sources being the most variable. The amplitude of the variations and their energy dependence are incompatible with variability being driven at hard X-rays by changes of the absorption column density. In general, the variations in the 14-24 and 35-100 keV bands are well correlated, suggesting a common origin of the variability across the BAT energy band. However, radio quiet AGN display on average 10 larger variations at 14-24 keV than at 35-100 keV and a softer-when-brighter behavior for most of the Seyfert galaxies with detectable spectral variability on month time scale. In addition, sources with harder spectra are found to be more variable than softer ones. These properties are generally consistent with a variable power law continuum, in flux and shape, pivoting at energies 50 keV, to which a constant reflection component is superposed. When the same time scales are considered, the timing properties of AGN at

  17. [O III]$\\lambda 5007$ and X-ray Properties of a Complete Sample of Hard X-ray Selected AGNs in the Local Universe

    CERN Document Server

    Ueda, Y; Ichikawa, K; Ishino, Y; Kniazev, A Y; Vaisanen, P; Ricci, C; Berney, S; Gandhi, P; Koss, M; Mushotzky, R; Terashima, Y; Trakhtenbrot, B; Crenshaw, M

    2015-01-01

    We study the correlation between the [O III]$\\lambda 5007$ and X-ray luminosities of local Active Galactic Nuclei (AGNs), using a complete, hard X-ray ($>10$ keV) selected sample in the Swift/BAT 9-month catalog. From our optical spectroscopic observations at the South African Astronomical Observatory and the literature, a catalog of [O III]$\\lambda 5007$ line flux for all 103 AGNs at Galactic latitudes of $|b|>15^\\circ$ is complied. Significant correlations with intrinsic X-ray luminosity ($L_{\\rm X}$) are found both for observed ($L_{\\rm [O~III]}$) and extinction-corrected ($L_{\\rm [O~III]}^{\\rm cor}$) luminosities, separately for X-ray unabsorbed and absorbed AGNs. We obtain the regression form of $L_{\\rm [O~III]}$ $\\propto L_{\\rm 2-10\\; keV}^{1.18\\pm0.07}$ and $L_{\\rm [O~III]}^{\\rm cor}$ $\\propto L_{\\rm 2-10\\; keV}^{1.16\\pm0.09}$ from the whole sample. The absorbed AGNs with low ($<$0.5\\%) scattering fractions in soft X-rays show on average smaller $L_{\\rm [O~III]}/L_{\\rm X}$ and $L_{\\rm [O~III]}^{\\rm ...

  18. Femtosecond time-resolved X-ray absorption spectroscopy of liquid using a hard X-ray free electron laser in a dual-beam dispersive detection method.

    Science.gov (United States)

    Obara, Yuki; Katayama, Tetsuo; Ogi, Yoshihiro; Suzuki, Takayuki; Kurahashi, Naoya; Karashima, Shutaro; Chiba, Yuhei; Isokawa, Yusuke; Togashi, Tadashi; Inubushi, Yuichi; Yabashi, Makina; Suzuki, Toshinori; Misawa, Kazuhiko

    2014-01-13

    We present femtosecond time-resolved X-ray absorption spectroscopy of aqueous solution using a hard x-ray free electron laser (SACLA) and a synchronized Ti:sapphire laser. The instrumental response time is 200 fs, and the repetition rate of measurement is 10 Hz. A cylindrical liquid beam 100 μm in diameter of aqueous ammonium iron(III) oxalate solution is photoexcited at 400 nm, and the transient X-ray absorption spectra are measured in the K-edge region of iron, 7.10 - 7.26 keV, using a dual X-ray beam dispersive detection method. Each of the dual beams has the pulse energy of 1.4 μJ, and pump-induced absorbance change on the order of 10(-3) is successfully detected. The photoexcited iron complex exhibits a red shifted iron K-edge with the appearance time constant of 260 fs. The X-ray absorption difference spectra, with and without the pump pulses, are independent of time delay after 1.5 ps up to 100 ps, indicating that the photoexcited species is long-lived.

  19. Upgrading multilayer zone plate technology for hard x-ray focusing

    International Nuclear Information System (INIS)

    Multilayer zone plate (MZP) technology for hard X-ray focusing was upgraded and its focusing performance was evaluated using 20-keV X-rays at the synchrotron beamline (BL24XU) of SPring-8. The MZP consists of MoSi2 and Si layers alternately deposited on a glass fiber by magnetron sputtering so that all zone boundaries satisfy the Fresnel zone configuration. The focused beam was evaluated using knife-edge scanning in which the measured intensity distribution is identical to the line spread function (LSF) in the focal plane. The focused beamsize of about 30 nm was estimated by oscillation peaks observed in the measured LSF according to Rayleigh’s criterion

  20. Development of grazing incidence multilayer mirrors for hard X-ray focusing telescopes

    DEFF Research Database (Denmark)

    Mao, Peter H.; Harrison, Fiona A.; Platonov, Yuriy Y.;

    1997-01-01

    We are developing depth-graded, multilayer-coated mirrors for astrophysical hard X-ray focusing telescopes. In this paper, we discuss the primary technical challenges associated with the multilayer coatings, and report on progress to date. We have sputtered constant d-spacing and depth-graded W...... was measured from specular reflectivity scans (θi = θr) using Cu Kα X-rays. The thin film stress was calculated from the change in curvature induced by the coating on flat glass substrates. Thickness and roughness uniformity were measured by taking specular reflectivity scans of a multilayer deposited....../Si multilayers onto 0.3-0.5 mm thick DURAN glass (AF45 and D263) and 0.4 mm thick epoxy replicated aluminum foils (ERAFs), both of which are potential mirror substrates. We have characterized the interfacial roughness, uniformity, and stress of the coatings. The average interfacial roughness of each multilayer...

  1. 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.

  2. 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.

  3. Upgrading multilayer zone plate technology for hard x-ray focusing

    Energy Technology Data Exchange (ETDEWEB)

    Hirotomo, Toshiki; Konishi, Shigeki [Graduate School of Material Science, University of Hyogo, Kamigori, Hyogo 678-1297 (Japan); SPring-8 Service Co., Ltd (Japan); Takano, Hidekazu, E-mail: htakano@sci.u-hyogo.ac.jp; Sumida, Kazuhiro; Tsusaka, Yoshiyuki; Kagoshima, Yasushi [Graduate School of Material Science, University of Hyogo, Kamigori, Hyogo 678-1297 (Japan); Koyama, Takahisa [Graduate School of Material Science, University of Hyogo, Kamigori, Hyogo 678-1297 (Japan); Japan Synchrotron Radiation Research Institute (JASRI/SPring-8) (Japan); Ichimaru, Satoshi; Ohchi, Tadayuki [NTT Advanced Technology Corporation (Japan); Takenaka, Hisataka [NTT Advanced Technology Corporation (Japan); TOYAMA Corporation (Japan)

    2016-01-28

    Multilayer zone plate (MZP) technology for hard X-ray focusing was upgraded and its focusing performance was evaluated using 20-keV X-rays at the synchrotron beamline (BL24XU) of SPring-8. The MZP consists of MoSi{sub 2} and Si layers alternately deposited on a glass fiber by magnetron sputtering so that all zone boundaries satisfy the Fresnel zone configuration. The focused beam was evaluated using knife-edge scanning in which the measured intensity distribution is identical to the line spread function (LSF) in the focal plane. The focused beamsize of about 30 nm was estimated by oscillation peaks observed in the measured LSF according to Rayleigh’s criterion.

  4. Characteristics of the flare acceleration region derived from simultaneous hard X-ray and radio observations

    CERN Document Server

    Reid, H A S; Kontar, E P

    2011-01-01

    We investigate the type III radio bursts and X-ray signatures of accelerated electrons in a well observed solar flare in order to find the spatial properties of the acceleration region. Combining simultaneous RHESSI hard X-ray flare data and radio data from Phoenix-2 and the Nan\\c{c}ay radioheliograph, the outward transport of flare accelerated electrons is analyzed. The observations show that the starting frequencies of type III bursts are anti-correlated with the HXR spectral index of solar flare accelerated electrons. We demonstrate both analytically and numerically that the type III burst starting location is dependent upon the accelerated electron spectral index and the spatial acceleration region size, but weakly dependent on the density of energetic electrons for relatively intense electron beams. Using this relationship and the observed anti-correlation, we estimate the height and vertical extent of the acceleration region, giving values of around $50$~Mm and $10$~Mm respectively. The inferred acceler...

  5. Host Galaxy Properties of the Swift BAT Ultra Hard X-Ray Selected AGN

    Science.gov (United States)

    Koss, Michael; Mushotzky, Richard; Veilleux, Sylvain; Winter, Lisa M.; Baumgartner, Wayne; Tueller, Jack; Gehrels, Neil; Valencic, Lynne

    2011-01-01

    We have assembled the largest sample of ultra hard X-ray selected (14-195 keV) AGN with host galaxy optical data to date, with 185 nearby (zAGN from the Swift Burst Alert Telescope (BAT) sample. The BAT AGN host galaxies have intermediate optical colors (u -- r and g -- r) that are bluer than a comparison sample of inactive galaxies and optically selected AGN from the Sloan Digital Sky Survey (SDSS) which are chosen to have the same stellar mass. Based on morphological classifications from the RC3 and the Galaxy Zoo, the bluer colors of BAT AGN are mainly due to a higher fraction of mergers and massive spirals than in the comparison samples. BAT AGN in massive galaxies (log Stellar Mass >10.5) have a 5 to 10 times higher rate of spiral morphologies than in SDSS AGN or inactive galaxies. We also see enhanced far-IR emission in BAT AGN suggestive of higher levels of star formation compared to the comparison samples. BAT AGN are preferentially found in the most massive host galaxies with high concentration indexes indicative of large bulge-to-disk ratios and large supermassive black holes. The narrow-line (NL) BAT AGN have similar intrinsic luminosities as the SDSS NL Seyferts based on measurements of [O III] Lambda 5007. There is also a correlation between the stellar mass and X-ray emission. The BAT AGN in mergers have bluer colors and greater ultra hard X-ray emission compared to the BAT sample as whole. In agreement with the Unified Model of AGN, and the relatively unbiased nature of the BAT sources, the host galaxy colors and morphologies are independent of measures of obscuration such as X-ray column density or Seyfert type. The high fraction of massive spiral galaxies and galaxy mergers in BAT AGN suggest that host galaxy morphology is related to the activation and fueling of local AGN.

  6. Evidence for Intermediate Polars as the Origin of the Galactic Center Hard X-ray Emission

    Science.gov (United States)

    Hailey, Charles J.; Mori, Kaya; Perez, Kerstin; Canipe, Alicia M.; Hong, Jaesub; Tomsick, John A.; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Fornasini, Francesca; Grindlay, Jonathan E.; Harrison, Fiona A.; Nynka, Melania; Rahoui, Farid; Stern, Daniel; Zhang, Shuo; Zhang, William W.

    2016-08-01

    Recently, unresolved hard (20-40 keV) X-ray emission has been discovered within the central 10 pc of the Galaxy, possibly indicating a large population of intermediate polars (IPs). Chandra and XMM-Newton measurements in the surrounding ˜50 pc imply a much lighter population of IPs with ≈ 0.5{M}⊙ . Here we use broadband NuSTAR observations of two IPs: TV Columbae, which has a fairly typical but widely varying reported mass of {M}{{WD}}≈ 0.5-1.0{M}⊙ , and IGR J17303-0601, with a heavy reported mass of {M}{{WD}}≈ 1.0-1.2{M}⊙ . We investigate how varying spectral models and observed energy ranges influences estimated white dwarf mass. Observations of the inner 10 pc can be accounted for by IPs with ≈ 0.9{M}⊙ , consistent with that of the CV population in general and the X-ray observed field IPs in particular. The lower mass derived by Chandra and XMM-Newton appears to be an artifact of narrow energy-band fitting. To explain the (unresolved) central hard X-ray emission (CHXE) by IPs requires an X-ray (2-8 keV) luminosity function (XLF) extending down to at least 5 × 1031 erg s-1. The CHXE XLF, if extended to the surrounding ˜50 pc observed by Chandra and XMM-Newton, requires that at least ˜20%-40% of the ˜9000 point sources are IPs. If the XLF extends just a factor of a few lower in luminosity, then the vast majority of these sources are IPs. This is in contrast to recent observations of the Galactic ridge, where the bulk of the 2-8 keV emission is ascribed to non-magnetic CVs.

  7. X-ray intensity-hardness correlation in Cyg X-1

    CERN Document Server

    Wen, L; Bradt, H V; Wen, Linqing; Cui, Wei; Bradt, Hale V.

    2000-01-01

    Using data from the All-Sky Monitor aboard the Rossi X-ray Timing Explorer (RXTE), we found that the 1.5-12 keV X-ray count rate of Cyg X-1 is, on time scales from 90 seconds to at least 10 days, strongly correlated with the spectral hardness of the source in the soft state, but is weakly anti-correlated with the latter in the hard state. The correlation shows an interesting evolution during the 1996 spectral state transition. The entire episode can be roughly divided into three distinct phases: (1) a 20-d transition phase from the hard state to the soft state, during which the correlation changes from being negative to positive, (2) a 50-d soft state with a steady positive correlation, and (3) a 20-d transition back to the hard state. The pointed RXTE observations confirmed the ASM results but revealed new behaviors of the source at energies beyond the ASM pass band. We discuss the implications of our findings.

  8. Resolving the hard X-ray emission of GX 5-1 with INTEGRAL

    DEFF Research Database (Denmark)

    Paizis, A.; Ebisawa, K.; Tikkanen, T.;

    2005-01-01

    We present the study of one year of INTEGRAL data on the neutron star low mass X-ray binary GX 5-1. Thanks to the excellent angular resolution and sensitivity of INTEGRAL, we are able to obtain a high quality spectrum of GX 5-1 from similar to 5keV to similar to 100 keV, for the first time without...... contamination from the nearby black hole candidate GRS 1758-258 above 20 keV. During our observations, GX 5-1 was mostly found in the horizontal and normal branch of its hardness intensity diagram. A clear hard X-ray emission is observed above similar to 30 keV which exceeds the exponential cut-off spectrum...... expected from lower energies. This spectral flattening may have the same origin of the hard components observed in other Z sources as it shares the property of being characteristic to the horizontal branch. The hard excess is explained by introducing Compton up-scattering of soft photons from the neutron...

  9. A SUZAKU SEARCH FOR NONTHERMAL EMISSION AT HARD X-RAY ENERGIES IN THE COMA CLUSTER

    International Nuclear Information System (INIS)

    The brightest cluster radio halo known resides in the Coma cluster of galaxies. The relativistic electrons producing this diffuse synchrotron emission should also produce inverse Compton emission that becomes competitive with thermal emission from the intracluster medium (ICM) at hard X-ray energies. Thus far, claimed detections of this emission in Coma are controversial. We present a Suzaku HXD-PIN observation of the Coma cluster in order to nail down its nonthermal hard X-ray content. The contribution of thermal emission to the HXD-PIN spectrum is constrained by simultaneously fitting thermal and nonthermal models to it and a spatially equivalent spectrum derived from an XMM-Newton mosaic of the Coma field. We fail to find statistically significant evidence for nonthermal emission in the spectra which are better described by only a single- or multitemperature model for the ICM. Including systematic uncertainties, we derive a 90% upper limit on the flux of nonthermal emission of 6.0 x 10-12 erg s-1 cm-2 (20-80 keV, for Γ = 2.0), which implies a lower limit on the cluster-averaged magnetic field of B>0.15 μG. Our flux upper limit is 2.5 times lower than the detected nonthermal flux from RXTE and BeppoSAX. However, if the nonthermal hard X-ray emission in Coma is more spatially extended than the observed radio halo, the Suzaku HXD-PIN may miss some fraction of the emission. A detailed investigation indicates that ∼50%-67% of the emission might go undetected, which could make our limit consistent with that of Rephaeli and Gruber and Fusco-Femiano et al. The thermal interpretation of the hard Coma spectrum is consistent with recent analyses of INTEGRAL and Swift data.

  10. Kilohertz sources of hard x rays and fast ions with femtosecond laser plasmas

    Science.gov (United States)

    Thoss, A.; Richardson, M.; Korn, G.; Faubel, M.; Stiel, H.; Vogt, U.; Elsaesser, T.

    2003-01-01

    We demonstrate a new, stable, kilohertz femtosecond laser plasma source of hard-x-ray continuum and Kα emission that uses a microscopic liquid jet target that is continuous and debris free. Plasmas produced by ultrashort (50-fs) intense laser pulses from a fine (10-30-μm diameter) liquid Ga jet emit bright 9.3- and 10.3-keV Kα and Kβ lines superimposed on a multikilovolt bremmstrahlung continuum. Kilohertz femtosecond x-ray sources will find many applications in time-resolved x-ray diffraction and microscopy studies. As high-intensity lasers become more compact and operate at increasingly high repetition-rates, they require a target configuration that is both repeatable from shot to shot and debris free. Our target provides a pristine, unperturbed filament surface at rates >100 kHz. A number of liquid metal targets are considered. We show the hard-x-ray spectrum described above. The source was generated by a 50-fs-duration, 1-kHz, 2-W, high-intensity Ti:sapphire laser. Using the same technology, we also generate forward-going sub-mega-electron-volt (sub-MeV) protons from a 10-μm liquid water target at 1-kHz repetition rates. Kilohertz sources of high-energy ions will find many applications in time-resolved particle interaction studies and will lead to efficient generation of short-lived isotopes for use in nuclear medicine and other applications. The protons were detected with CR-39 track detectors in both the forward and the backward directions up to energies of ~500 keV. As the intensity of compact high-repetition-rate lasers sources increases, we can expect improvements in the energy, conversion efficiency, and directionality to occur. The effect of these developments is discussed. As compact, high-repetition-rate femtosecond laser technology reaches focused intensities of ~1019 W/cm2, many new applications of high-repetition-rate hard-x-ray and MeV ion sources will become practical.

  11. ID16B: a hard X-ray nanoprobe beamline at the ESRF for nano-analysis.

    Science.gov (United States)

    Martínez-Criado, Gema; Villanova, Julie; Tucoulou, Rémi; Salomon, Damien; Suuronen, Jussi-Petteri; Labouré, Sylvain; Guilloud, Cyril; Valls, Valentin; Barrett, Raymond; Gagliardini, Eric; Dabin, Yves; Baker, Robert; Bohic, Sylvain; Cohen, Cédric; Morse, John

    2016-01-01

    Within the framework of the ESRF Phase I Upgrade Programme, a new state-of-the-art synchrotron beamline ID16B has been recently developed for hard X-ray nano-analysis. The construction of ID16B was driven by research areas with major scientific and societal impact such as nanotechnology, earth and environmental sciences, and bio-medical research. Based on a canted undulator source, this long beamline provides hard X-ray nanobeams optimized mainly for spectroscopic applications, including the combination of X-ray fluorescence, X-ray diffraction, X-ray excited optical luminescence, X-ray absorption spectroscopy and 2D/3D X-ray imaging techniques. Its end-station re-uses part of the apparatus of the earlier ID22 beamline, while improving and enlarging the spectroscopic capabilities: for example, the experimental arrangement offers improved lateral spatial resolution (∼50 nm), a larger and more flexible capability for in situ experiments, and monochromatic nanobeams tunable over a wider energy range which now includes the hard X-ray regime (5-70 keV). This paper describes the characteristics of this new facility, short-term technical developments and the first scientific results. PMID:26698084

  12. Suzaku observations of the hard X-ray spectrum of Vela Jr. (SNR RX J0852.0-4622)

    Science.gov (United States)

    Takeda, Sawako; Bamba, Aya; Terada, Yukikatsu; Tashiro, Makoto S.; Katsuda, Satoru; Yamazaki, Ryo; Ohira, Yutaka; Iwakiri, Wataru

    2016-06-01

    We report the results of Suzaku observations of the young supernova remnant, Vela Jr. (RX J0852.0-4622), which is known to emit synchrotron X-rays, as well as TeV gamma-rays. Utilizing 39 Suzaku mapping observation data from Vela Jr., a significant hard X-ray emission is detected with the hard X-ray detector (HXD) from the northwest TeV-emitting region. The X-ray spectrum is reproduced well by a single power-law model with a photon index of 3.15^{+1.18}_{-1.14} in the 12-22 keV band. Compiling this hard X-ray spectrum with the soft X-ray spectrum simultaneously observed with the X-ray imaging spectrometer (XIS) onboard Suzaku, we find that the wide-band X-ray spectrum in the 2-22 keV band is reproduced with a single power-law or concave broken power-law model, which are statistically consistent with each other. Whichever of the two models, single or broken power-law, is appropriate, clearly the spectrum has no roll-off structure. Applying this result to the method introduced in Yamazaki et al. (2014, Res. Astron. Astrophys., 14, 165), we find that a one-zone synchrotron model with electron spectrum having a power-law plus exponential cut-off may not be applicable to Vela Jr.

  13. Uncooled Radiation Hard Large Area SiC X-ray and EUV Detectors and 2D Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project seeks to design, fabricate, characterize and commercialize large area, uncooled and radiative hard 4H-SiC EUV ? soft X-ray detectors capable of ultra...

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

    Science.gov (United States)

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

    2016-05-01

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

  15. New AGN classifications in the Swift/BAT All-Sky Hard X-ray Survey

    CERN Document Server

    Parisi, Pietro

    2011-01-01

    Through an optical campaign performed at the San Pedro Martir (Mexico) Telescope and using the 6dF archive (http://www.aao.gov.au/local/www/6df, Jones et al. 2004), we determine or give a better classification for 8 newly discovered Active Galactic Nuclei (AGN) in the Swift/BAT 22-months All-sky Hard X-ray Survey (Baumgartner et al. 2008, Tueller et al. 2010). All these objects have observations taken with Swift/XRT or Chandra or XMM archival data which allowed us to pinpoint their optical counterpart thanks to the precise (better than a few arcsec) soft X-ray positions afforded by these observatories. This information enabled us to obtain optical spectra of all these counterparts, since only three spectra are available on-line, but not flux calibrated, allowing us to reveal their real nature (Baumgartner et al. 2008 give only a tentative classification based upon their X-ray properties). Here we present the spectra, along with the corresponding finding charts obtained from the DSS-II red survey, of these 8 s...

  16. Examining the hard X-ray emission of the redback PSR J2129-0429

    Science.gov (United States)

    Noori, Hind Al; Roberts, Mallory; McLaughlin, Maura; Hessels, Jason; Breton, Rene; 17077031498

    2016-06-01

    We present new NuStar data of the redback millisecond pulsar (MSP) system PSR J2129-0429. Redback systems are important when it comes to understanding the evolution of MSPs, in terms of pulsar recycling, as they have been observed to transition between a state of accretion, where emission is in the optical and X-ray regimes, and a state of eclipsed radio pulsation. This system is particularly interesting due to some peculiarities: it has a more massive companion as well as a stronger magnetic field than other redbacks, indicating that the system is in a fairly early stage of recycling. It’s X-ray lightcurve (as obtained from XMM-Newton data) has a very hard power-law component and exhibits an efficiency of a few percent in X-ray. With the NuStar data, the spectrum can be seen to extend to ~30 keV. Additionally, it shows strong orbital variation, about 5 times greater than is typical for other systems, and is also very clearly double peaked. Hints of similar peaks have been observed in the lightcurves of other redback systems; hence, this system can help in understanding the intrabinary shock of eclipsing MSPs.

  17. Satellite observations of lightning-induced hard X-ray flux enhancements in the conjugate region

    Directory of Open Access Journals (Sweden)

    R. Bučík

    2006-08-01

    Full Text Available Preliminary examination of October-December 2002 SONG (SOlar Neutron and Gamma rays data aboard the Russian CORONAS-F (Complex Orbital Near-Earth Observations of the Activity of the Sun low-altitude satellite has revealed many X-ray enhanced emissions (30–500 keV in the slot region (L ~ 2–3 between the Earth's radiation belts. In one case, CORONAS-F data were analyzed when the intense hard X-ray emissions were seen westward of the South Atlantic Anomaly in a rather wide L shell range from 1.7 to 2.6. Enhanced fluxes observed on day 316 (12 November were most likely associated with a Major Severe Weather Outbreak in Eastern USA, producing extensive lightning flashes, as was documented by simultaneous optical observations from space. We propose that whistler mode signals from these lightning discharges cause precipitation of energetic electrons from terrestrial trapped radiation belts, which, in turn, produce atmospheric X-rays in the Southern Hemisphere.

  18. Transient pulsar dynamics in hard x-rays: Prognoz 9 and GRIF "Mir" space experiments data

    CERN Document Server

    Kudryavtsev, M I; Bogomolov, V V

    2006-01-01

    The long-term observations of the Galactic Centre as well as the Galactic anti-Centre regions in hard X-rays (10-300 keV) were made in experiments on board Prognoz-9 satellite and "Mir" orbital station (GRIF experiment). Some transient pulsars including A0535+262, GS1722-36, 4U1145-619, A1118-615, EXO2030+37, Sct X-1, SAX J2103.5+4545, IGR 16320-4751, IGR 16465-4507 were observed. The pulsation flux components of A0535+26 and GS1722-36 X-ray emission were revealed at significant level. For other observed pulsars the upper limits of pulsation intensity were obtained. The mean pulsation profiles of A0535+26 in different energy ranges as well as the energy spectra were obtained at different stages of outburst decreasing. The pulsation intensity-period behavior does not contradict the well-known correlation between spin-up rate and X-ray flux, while the stable character of the energy spectrum power index indicates on the absence of thermal component. The energy spectrum and mean pulsation profiles were also obtai...

  19. Optimization of the Design of the Hard X-ray Polarimeter X-Calibur

    CERN Document Server

    Guo, Qingzhen; Garson, Alfred; Kislat, Fabian; Fleming, David; Krawczynski, Henric; 10.1016/j.astropartphys.2012.11.006

    2012-01-01

    We report on the optimization of the hard X-ray polarimeter X-Calibur for a high-altitude balloon-flight in the focal plane of the InFOC{\\mu}S X-ray telescope from Fort Sumner (NM) in Fall 2013. X-Calibur combines a low-Z scintillator slab to Compton-scatter photons with a high-Z Cadmium Zinc Telluride (CZT) detector assembly to photo-absorb the scattered photons. The detector makes use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity and reaches a sensitivity close to the best theoretically possible. In this paper, we discuss the optimization of the design of the instrument based on Monte Carlo simulations of polarized and unpolarized X-ray beams and of the most important background components. We calculate the sensitivity of the polarimeter for the upcoming balloon flight from Fort Sumner and for additional longer balloon flights with higher throughput mirrors. We conclude by empha...

  20. The influence of albedo on the size of hard X-ray flare sources

    CERN Document Server

    Battaglia, Marina; Hannah, Iain G

    2010-01-01

    Context: Hard X-rays from solar flares are an important diagnostic of particle acceleration and transport in the solar atmosphere. Any observed X-ray flux from on-disc sources is composed of direct emission plus Compton backscattered photons (albedo). This affects both the observed spectra and images as well as the physical quantities derived from them such as the spatial and spectral distributions of accelerated electrons or characteristics of the solar atmosphere. Aims: We propose a new indirect method to measure albedo and to infer the directivity of X-rays in imaging using RHESSI data. Methods: Visibility forward fitting is used to determine the size of a disc event observed by RHESSI as a function of energy. This is compared to the sizes of simulated sources from a Monte Carlo simulation code of photon transport in the chromosphere for different degrees of downward directivity and true source sizes to find limits on the true source size and the directivity. Results: The observed full width half maximum o...

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

    Energy Technology Data Exchange (ETDEWEB)

    Rutherford, Michael E.; Chapman, David J.; White, Thomas G. [Imperial College London, London (United Kingdom); Drakopoulos, Michael [Diamond Light Source, I12 Joint Engineering, Environmental, Processing (JEEP) Beamline, Didcot, Oxfordshire (United Kingdom); Rack, Alexander [European Synchrotron Radiation Facility, Grenoble (France); Eakins, Daniel E., E-mail: d.eakins@imperial.ac.uk [Imperial College London, London (United Kingdom)

    2016-03-24

    Scintillator performance in time-resolved, hard, indirect detection X-ray studies on the sub-microsecond timescale at synchrotron light sources is reviewed, modelled and examined experimentally. LYSO:Ce is found to be the only commercially available crystal suitable for these experiments. 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)

  2. Solution Phase Molecular Dynamics Probed with Synchrotron Hard X-rays

    Science.gov (United States)

    March, Anne; Doumy, Gilles; Kanter, Elliot; Southworth, Stephen; Young, Linda; Nemeth, Zoltan; Vankó, Gyorgy; Assefa, Tadesse; Gawelda, Wojciech

    2013-05-01

    The ability to measure short-lived transient states during a chemical reaction is key to understanding many important processes such as oxygen binding in hemeproteins and electron transport in photosynthesis. Time resolved hard x-ray spectroscopies, which are based on laser-pump/x-ray-probe methods, are a unique tool because unlike UV-VIS techniques they are element specific and can provide electronic and structural information with atomic resolution in the vicinity of a particular atom or ion. These characteristics make them particularly powerful for studying molecules in complex environments such as solutions. Using a MHz, picosecond, high average power laser system implemented at Sector 7ID-D of the Advanced Photon Source we have been developing time resolved x-ray emission techniques to track the evolution of photoexcited molecules in solution. We will present recent studies which include the ligand substitution reaction and hydrated electron formation in the coordination complex ferrocyanide Fe(CN)64-. This work was supported by the Chemical Sciences, Geosciences, and Biosciences Division and the Advanced Photon Source by the Office of Basic Energy Sciences, Office of Science, US Dept of Energy, Contract DE-AC02-06CH11357.

  3. Quasi-periodic Variations in the Hard X-ray emission of a Large Arcade Flare

    CERN Document Server

    Jakimiec, Jerzy

    2013-01-01

    Quasi-periodic oscillations of the hard X-ray (HXR) emission of the large flare of 2 November 1991 have been investigated using HXR light curves and soft X-ray and HXR images recorded by the {\\sl Yohkoh} X-ray telescopes. The results of the analysis of these observations are the following: i) The observations confirm that electrons are accelerated in oscillating magnetic traps which are contained within the cusp magnetic structure. ii) The amplitude of the HXR pulses increase due to the increase in the amplitude of the magnetic trap oscillations and the increase in the density within the traps caused by the chromospheric evaporation upflow. iii) The increase in the amplitude of the HXR pulses terminates when further increase in the density inside the traps inhibits the acceleration of electrons. iv) The model of oscillating magnetic traps is able to explain time variation of the electron precipitation, strong asymmetry in precipitation of accelerated electrons, and systematic differences in the precipitation ...

  4. Characteristics of the flare acceleration region derived from simultaneous hard X-ray and radio observations

    Science.gov (United States)

    Reid, H. A. S.; Vilmer, N.; Kontar, E. P.

    2011-05-01

    We investigate the type III radio bursts and X-ray signatures of accelerated electrons in a well-observed solar flare in order to find the spatial properties of the acceleration region. Combining simultaneous RHESSI hard X-ray flare data and radio data from Phoenix-2 and the Nançay radioheliograph, the outward transport of flare accelerated electrons is analysed. The observations show that the starting frequencies of type III bursts are anti-correlated with the HXR spectral index of solar flare accelerated electrons. We demonstrate both analytically and numerically that the type III burst starting location is dependent upon the accelerated electron spectral index and the spatial acceleration region size, but weakly dependent on the density of energetic electrons for relatively intense electron beams. Using this relationship and the observed anti-correlation, we estimate the height and vertical extent of the acceleration region, giving values of around 50 Mm and 10 Mm, respectively. The inferred acceleration height and size suggest that electrons are accelerated well above the soft X-ray loop-top, which could be consistent with the electron acceleration between 40 Mm and 60 Mm above the flaring loop.

  5. X-ray spectromicroscopy investigation of soft and hard breakdown in RRAM devices

    Science.gov (United States)

    Carta, D.; Guttmann, P.; Regoutz, A.; Khiat, A.; Serb, A.; Gupta, I.; Mehonic, A.; Buckwell, M.; Hudziak, S.; Kenyon, A. J.; Prodromakis, T.

    2016-08-01

    Resistive random access memory (RRAM) is considered an attractive candidate for next generation memory devices due to its competitive scalability, low-power operation and high switching speed. The technology however, still faces several challenges that overall prohibit its industrial translation, such as low yields, large switching variability and ultimately hard breakdown due to long-term operation or high-voltage biasing. The latter issue is of particular interest, because it ultimately leads to device failure. In this work, we have investigated the physicochemical changes that occur within RRAM devices as a consequence of soft and hard breakdown by combining full-field transmission x-ray microscopy with soft x-ray spectroscopic analysis performed on lamella samples. The high lateral resolution of this technique (down to 25 nm) allows the investigation of localized nanometric areas underneath permanent damage of the metal top electrode. Results show that devices after hard breakdown present discontinuity in the active layer, Pt inclusions and the formation of crystalline phases such as rutile, which indicates that the temperature increased locally up to 1000 K.

  6. Sensitivity of stacked imaging detectors to hard X-ray polarization

    CERN Document Server

    Muleri, Fabio

    2012-01-01

    The development of multi-layer optics which allow to focus photons up to 100 keV and more promises an enormous jump in sensitivity in the hard X-ray energy band. This technology is already planned to be exploited by future missions dedicated to spectroscopy and imaging at energies >10 keV, e.g. Astro-H and NuSTAR. Nevertheless, our understanding of the hard X-ray sky would greatly benefit from carrying out contemporaneous polarimetric measurements, because the study of hard spectral tails and of polarized emission often are two complementary diagnostics of the same non-thermal and acceleration processes. At energies above a few tens of keV, the preferred technique to detect polarization involves the determination of photon directions after a Compton scattering. Many authors have asserted that stacked detectors with imaging capabilities can be exploited for this purpose. If it is possible to discriminate those events which initially interact in the first detector by Compton scattering and are subsequently abso...

  7. Hard X-ray Tail Discovered in the Clocked Burster GS 1826-238

    CERN Document Server

    Rodi, James; Roques, Jean-Pierre

    2015-01-01

    The LMXB NS GS 1826-238 was discovered by Ginga in 1988 September. Due to the presence of quasi-periodicity in the type I X-ray burst rate, the source has been a frequent target of X-ray observations for almost 30 years. Though the bursts were too soft to be detected by INTEGRAL/SPI, the persistent emission from GS 1826-238 was detected over 150 keV during the ~10 years of observations. Spectral analysis found a significant high-energy excess above a Comptonization model that is well fit by a power law, indicating an additional spectral component. Most previously reported spectra with hard tails in LMXB NS have had an electron temperature of a few keV and a hard tail dominating above ~50 keV with an index of \\Gamma ~ 2-3. GS 1826-238 was found to have a markedly different spectrum with $ kT_e \\sim 20 $ keV and a hard tail dominating above ~150 keV with an index of \\Gamma ~ 1.8, more similar to BHXRB. We report on our search for long-term spectral variability over the 25-370 keV energy range and on a compariso...

  8. A Balloon-borne Measurement of High Latitude Atmospheric Neutrons Using a LiCAF Neutron Detector

    CERN Document Server

    Kole, Merlin; Fukuda, Kentaro; Ishizu, Sumito; Jackson, Miranda; Kamae, Tune; Kawaguchi, Noriaki; Kawano, Takafumi; Kiss, Mózsi; Moretti, Elena; Salinas, Maria Fernanda Muñoz; Pearce, Mark; Rydström, Stefan; Takahashi, Hiromitsu; Yanagida, Takayuki

    2013-01-01

    PoGOLino is a scintillator-based neutron detector. Its main purpose is to provide data on the neutron flux in the upper stratosphere at high latitudes at thermal and nonthermal energies for the PoGOLite instrument. PoGOLite is a balloon borne hard X-ray polarimeter for which the main source of background stems from high energy neutrons. No measurements of the neutron environment for the planned flight latitude and altitude exist. Furthermore this neutron environment changes with altitude, latitude and solar activity, three variables that will vary throughout the PoGOLite flight. PoGOLino was developed to study the neutron environment and the influences from these three variables upon it. PoGOLino consists of two Europium doped Lithium Calcium Aluminium Fluoride (Eu:LiCAF) scintillators, each of which is sandwiched between 2 Bismuth Germanium Oxide (BGO) scintillating crystals, which serve to veto signals produced by gamma-rays and charged particles. This allows the neutron flux to be measured even in high rad...

  9. HEAO 1 hard X-ray observations of three Abell clusters of galaxies

    Science.gov (United States)

    Rephaeli, Y.; Gruber, D. E.; Rothschild, R. E.

    1987-01-01

    The results of an analysis of the HEAO 1 hard X-ray measurements of the Coma, A1367, and A2319 galactic clusters are presented. All three clusters have been observed to have diffuse, extended radio emission in their central regions. The results are analyzed together with radio measurements to determine the energetic electron density and the strength of the mean intracluster magnetic field in these clusters. The results show that there is no clear evidence for nonthermal flux in the spectra of the three clusters at the sensitivity limit of the low energy detectors used.

  10. Optical Identification of Four Hard X-ray Sources from the Swift All-Sky Survey

    OpenAIRE

    Lutovinov, A.; Burenin, R.; Revnivtsev, M.; Sazonov, S; Sholukhova, O.; Valeev, A.

    2012-01-01

    We present the results of our optical identifications of four hard X-ray sources from the Swift all-sky survey. We obtained optical spectra for each of the program objects with the 6-m BTA telescope (Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz), which allowed their nature to be established. Two sources (SWIFT J2237.2+6324} and SWIFT J2341.0+7645) are shown to belong to the class of cataclysmic variables (suspected polars or intermediate polars). The measured...

  11. Hard X-ray Detection and Timing of Accretion-Powered Pulsars with BATSE

    OpenAIRE

    Chakrabarty, Deepto; Prince, Thomas A.

    1996-01-01

    The BATSE all-sky monitor on the Compton Gamma Ray Observatory is a superb tool for the study of accretion-powered pulsars. In the first part of this thesis, I describe its capabilities for hard X-ray observations above 20 keV, present techniques for timing analysis of the BATSE data, and discuss general statistical issues for the detection of pulsed periodic signals in both the time and frequency domains. BATSE’s 1-day pulsed sensitivity in the 20–60 keV ...

  12. INTEGRAL discovery of a new hard X-ray transient: IGR J17177-3656

    DEFF Research Database (Denmark)

    Frankowski, A.; Ferrigo, C.; Bozzo, E.;

    2011-01-01

    We report on the discovery of a new transient source, IGR J17177-3656, detected during the INTEGRAL observation performed from 2011-03-15 09:23 to 2011-03-15 22:42 UT. The source was detected by IBIS/ISGRI at a significance level of 13 and 9 standard deviations, in the 20-40 keV and 40-80 keV ene...... = 1.2e22 cm-2). We encourage multiwavelength observations to investigate the nature of the system, which has the typical characteristics of either an X-ray transient in an initial hard state or a transient highly absorbed source....

  13. Phase-matched generation of coherent soft and hard X-rays using IR lasers

    Science.gov (United States)

    Popmintchev, Tenio V.; Chen, Ming-Chang; Bahabad, Alon; Murnane, Margaret M.; Kapteyn, Henry C.

    2013-06-11

    Phase-matched high-order harmonic generation of soft and hard X-rays is accomplished using infrared driving lasers in a high-pressure non-linear medium. The pressure of the non-linear medium is increased to multi-atmospheres and a mid-IR (or higher) laser device provides the driving pulse. Based on this scaling, also a general method for global optimization of the flux of phase-matched high-order harmonic generation at a desired wavelength is designed.

  14. Hard X-ray nanoimaging method using local diffraction from metal wire

    Energy Technology Data Exchange (ETDEWEB)

    Takano, Hidekazu, E-mail: htakano@sci.u-hyogo.ac.jp; Konishi, Shigeki; Shimomura, Sho; Azuma, Hiroaki; Tsusaka, Yoshiyuki; Kagoshima, Yasushi [Center for Novel Material Science under Multi-Extreme Conditions, Graduate School of Material Science, University of Hyogo, Kamigori, Hyogo 678-1297 (Japan)

    2014-01-13

    A simple hard X-ray imaging method achieving a high spatial resolution is proposed. Images are obtained by scanning a metal wire through the wave field to be measured and rotating the sample to collect data for back projection calculations; the local diffraction occurring at the edges of the metal wire operates as a narrow line probe. In-line holograms of a test sample were obtained with a spatial resolution of better than 100 nm. The potential high spatial resolution of this method is shown by calculations using diffraction theory.

  15. The Variable Hard X-Ray Emission of NGC4945 as Observed by NuSTAR

    Science.gov (United States)

    Puccetti, Simonetta; Comastri, Andrea; Fiore, Fabrizio; Arevalo, Patricia; Risaliti, Guido; Bauer, Franz E.; Brandt, William N.; Stern, Daniel; Harrison, Fiona A.; Alexander, David M.; Boggs, Steve E.; Christensen, Finn E.; Craig, William W.; Gandhi, Poshak; Hailey, Charles J.; Koss, Michael R.; Lansbury, George B.; Luo, Bin; Madejski, Greg M.; Matt, Giorgio; Walton, Dominic J.; Zhang, Will

    2014-01-01

    We present a broadband (approx. 0.5 - 79 keV) spectral and temporal analysis of multiple NuSTAR observations combined with archival Suzaku and Chandra data of NGC4945, the brightest extragalactic source at 100 keV. We observe hard X-ray (> 10 keV) flux and spectral variability, with flux variations of a factor 2 on timescales of 20 ksec. A variable primary continuum dominates the high energy spectrum (> 10 keV) in all the states, while the reflected/scattered flux which dominates at E< 10 keV stays approximately constant. From modelling the complex reflection/transmission spectrum we derive a Compton depth along the line of sight of Thomson approx.2.9, and a global covering factor for the circumnuclear gas of approx. 0.15. This agrees with the constraints derived from the high energy variability, which implies that most of the high energy flux is transmitted, rather that Compton-scattered. This demonstrates the effectiveness of spectral analysis in constraining the geometric properties of the circumnuclear gas, and validates similar methods used for analyzing the spectra of other bright, Compton-thick AGN. The lower limits on the e-folding energy are between 200 - 300 keV, consistent with previous BeppoSAX, Suzaku and Swift BAT observations. The accretion rate, estimated from the X-ray luminosity and assuming a bolometric correction typical of type 2 AGN, is in the range approx. 0.1 - 0.3 lambda(sub Edd) depending on the flux state. The substantial observed X-ray luminosity variability of NGC4945 implies that large errors can arise from using single-epoch X-ray data to derive L/L(sub Edd) values for obscured AGNs.

  16. The variable hard X-ray emission of NGC 4945 as observed by NuSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Puccetti, Simonetta [ASDC-ASI, Via del Politecnico, I-00133 Roma (Italy); Comastri, Andrea [INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Fiore, Fabrizio [INAF-Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monte Porzio Catone (RM) (Italy); Arévalo, Patricia; Bauer, Franz E. [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, 306, Santiago 22 (Chile); Risaliti, Guido [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Brandt, William N.; Luo, Bin [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Harrison, Fiona A. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Alexander, David M.; Gandhi, Poshak; Lansbury, George B. [Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Boggs, Steve E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, Finn E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, 2800 Lyngby (Denmark); Hailey, Charles J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Koss, Michael J. [Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Madejski, Greg M. [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Matt, Giorgio [Dipartimento di Matematica e Fisica, Universit' a Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy); and others

    2014-09-20

    We present a broadband (∼0.5-79 keV) spectral and temporal analysis of multiple NuSTAR observations combined with archival Suzaku and Chandra data of NGC 4945, the brightest extragalactic source at 100 keV. We observe hard X-ray (>10 keV) flux and spectral variability, with flux variations of a factor of two on timescales of 20 ks. A variable primary continuum dominates the high-energy spectrum (>10 keV) in all states, while the reflected/scattered flux that dominates at E <10 keV stays approximately constant. From modeling the complex reflection/transmission spectrum, we derive a Compton depth along the line of sight of τ{sub Thomson} ∼ 2.9, and a global covering factor for the circumnuclear gas of ∼0.15. This agrees with the constraints derived from the high-energy variability, which implies that most of the high-energy flux is transmitted rather than Compton-scattered. This demonstrates the effectiveness of spectral analysis at constraining the geometric properties of the circumnuclear gas, and validates similar methods used for analyzing the spectra of other bright, Compton-thick active galactic nuclei (AGNs). The lower limits on the e-folding energy are between 200 and 300 keV, consistent with previous BeppoSAX, Suzaku, and Swift Burst Alert Telescope observations. The accretion rate, estimated from the X-ray luminosity and assuming a bolometric correction typical of type 2 AGN, is in the range ∼0.1-0.3 λ{sub Edd} depending on the flux state. The substantial observed X-ray luminosity variability of NGC 4945 implies that large errors can arise from using single-epoch X-ray data to derive L/L {sub Edd} values for obscured AGNs.

  17. ASCA observations of deep ROSAT fields V. The X-ray spectrum of hard X-ray selected QSOs

    CERN Document Server

    Pappa, A; Georgantopoulos, I; Griffiths, R E; Boyle, B J; Shanks, T

    2001-01-01

    We present an analysis of the \\rosat and \\asca spectra of 21 broad line AGN (QSOs) with $z\\sim 1$ detected in the 2-10 keV band with the \\asca \\gis. The summed spectrum in the \\asca band is well described by a power-law with $\\Gamma=1.56\\pm0.18$, flatter that the average spectral index of bright QSOs and consistent with the spectrum of the X-ray background in this band. The flat spectrum in the \\asca band could be explained by only a moderate absorption ($\\sim 10^{22} \\rm cm^{-2}$) assuming the typical AGN spectrum ie a power-law with $\\Gamma$=1.9. This could in principle suggest that some of the highly obscured AGN, required by most X-ray background synthesis models, may be associated with normal blue QSOs rather than narrow-line AGN. However, the combined 0.5-8 keV \\asca-\\rosat spectrum is well fit by a power-law of $\\Gamma=1.7\\pm0.2$ with a spectral upturn at soft energies. It has been pointed out that such an upturn may be an artefact of uncertainties in the calibration of the ROSAT or ASCA detectors. Nev...

  18. INTEGRAL hard X-ray spectra of the cosmic X-ray background and Galactic ridge emission

    CERN Document Server

    Turler, M; Courvoisier, T J -L; Lubinski, P; Neronov, A; Produit, N; Walter, R

    2010-01-01

    We derive the spectra of the cosmic X-ray background (CXB) and of the Galactic ridge X-ray emission (GRXE) in the ~20-200 keV range from the data of the IBIS instrument aboard the INTEGRAL satellite obtained during the four dedicated Earth-occultation observations of early 2006. We analyse the modulation of the IBIS/ISGRI detector counts induced by the passage of the Earth through the field of view of the instrument. Unlike previous studies, we do not fix the spectral shape of the various contributions, but model instead their spatial distribution and derive for each of them the expected modulation of the detector counts. The spectra of the diffuse emission components are obtained by fitting the normalizations of the model lightcurves to the observed modulation in different energy bins. The obtained CXB spectrum is consistent with the historic HEAO-1 results and falls slightly below the spectrum derived with Swift/BAT. A 10% higher normalization of the CXB cannot be completely excluded, but it would imply an ...

  19. Lens coupled tunable Young's double pinhole system for hard X-ray spatial coherence characterization.

    Science.gov (United States)

    Lyubomirskiy, Mikhail; Snigireva, Irina; Snigirev, Anatoly

    2016-06-13

    We have implemented a modified Young's double slit experiment using pinholes with tunable separation distance coupled with compound refractive lens for hard X-ray spatial coherence characterization. Varying distance between the apertures provides a high sensitivity to the determination of spatial coherence across a wide range of experimental parameters. The use of refractive lenses as a Fourier transformer ensures far field registration conditions and allows the realization of a very compact experimental setup in comparison with the classical Young technique and its derivatives. The tunable double aperture interferometer was experimentally tested at the ESRF ID06 beamline in the energy range from 8 to 25 keV. The spatial coherence and the source size were measured by evaluating the visibility of the interference fringes at various separation distances between the apertures and this value agrees very well with the data obtained by other techniques. The proposed scheme can be used for comprehensive characterization of the coherence properties of the source on low emittance synchrotrons in the hard X-ray region.

  20. Stellar population properties for a sample of hard X-ray AGNs

    CERN Document Server

    Morelli, L; Masetti, N; Parisi, P; Landi, R; Maiorano, E; Minniti, D; Galaz, G

    2013-01-01

    The aim of this paper is to study the stellar population of galaxies hosting an active galactic nucleus (AGN). We studied a sub-sample of hard X-ray emitting AGNs from the INTEGRAL and Swift catalogs which were previously identified and characterized through optical spectroscopy. Our analysis provides complementary information, namely age and metallicity, which is necessary to complete the panoramic view of such interesting objects. We selected hard X-ray emitting objects identified as AGNs by checking their optical spectra in search for absorption lines suitable for the stellar population analysis. We obtained a final sample consisting of 20 objects with redshift lower than 0.3. We used the full-spectrum fitting method and, in particular, the penalized pixel one applying the PPXF code. After masking all the regions affected by emission lines, we fitted the spectra with the MILES single stellar population templates and we derived mass-weighted ages and metallicities. Most of the objects in our sample show an ...

  1. Morphology and Spectral Behavior of Solar Hard X-Ray Sources

    Directory of Open Access Journals (Sweden)

    F. C. R. Fernandes

    2002-01-01

    Full Text Available Las imágenes de 17 fulguraciones solares, correspondiendo a 61 explosiones de rayos-X observados en cuatro rangos de energía (14-23, 23-33, 33-53 y 53-93 keV por el experimento Hard X-Ray Telescope (HXT a bordo del satélite Yohkoh, han sido investigadas. Las imágenes sugieren que el tamaño de las fuentes de rayos-X duros es del orden de 20 segundos de arco y que existen 3 tipos: fuentes individuales simples (30%, fuentes dobles (41%, con separación mínima típica de 30{40 segundos de arco y fuentes múltiples (29%. Hemos ajustado un único espectro de potencia para las emisiones de rayos-X en el rango de 20{830 keV utilizando datos del experimento Hard X-Ray Spectrometer (HXS. La evolución temporal del espectro de estas explosiones también fue estudiada. El comportamiento típico del índice es "blando-duro-blando".

  2. Constraining the hard X-ray properties of the quiet Sun with new RHESSI observations

    CERN Document Server

    Hannah, I G; Hurford, G J; Lin, R P

    2010-01-01

    We present new RHESSI upper limits in the 3-200 keV energy range for solar hard X-ray emission in the absence of flares and active regions, i.e. the quiet Sun, using data obtained between July 2005 and April 2009. These new limits, substantially deeper than any previous ones, constrain several physical processes that could produce hard X-ray emission. These include cosmic-ray effects and the generation of axions within the solar core. The data also limit the properties of "nanoflares", a leading candidate to explain coronal heating. We find it unlikely for nanoflares involving nonthermal effects to heat the corona because such events would require a steep electron spectrum E^{-\\delta} with index \\delta > 5 extending to very low energies (<1 keV), into the thermal energy range. We also use the limits to constrain the parameter space of an isothermal model and coronal thin-target emission models (powerlaw and kappa distributions)

  3. The Clustering of XMM-Newton Hard X-ray Sources

    CERN Document Server

    Basilakos, S; Plionis, M; Georgantopoulos, I

    2004-01-01

    This paper presents the clustering properties of hard (2-8 keV) X-ray selected sources detected in a wide field ($\\approx \\rm 2 deg^{2}$) shallow [$f_X(\\rm 2-8 keV)\\approx 10^{-14}\\rm erg cm^{-2} s^{-1}$] and contiguous XMM-{\\it Newton} survey. We perform an angular correlation function analysis using a total of 171 sources to the above flux limit. We detect a $\\sim 4\\sigma$ correlation signal out to 300 arcsec with $w(\\theta < 300^{''})\\simeq 0.13 \\pm 0.03$. Modeling the two point correlation function as a power law of the form $w(\\theta)=(\\theta_{\\circ}/\\theta)^{\\gamma-1}$ we find: $\\theta_{\\circ}=48.9^{+15.8}_{-24.5}$ arcsec and $\\gamma=2.2\\pm {0.30}$. Fixing the correlation function slope to $\\gamma=1.8$ we obtain $\\theta_{\\circ}=22.2^{+9.4}_{-8.6}$ arcsec. Using Limber's intergral equation and a variety of possible luminosity functions of the hard X-ray population, we find a relatively large correlation length, ranging from $r_{\\circ}\\sim 9$ to 19 $h^{-1}$ Mpc (for $\\gamma=1.8$ and the {\\em concordanc...

  4. Long-term variability of AGN at hard X-rays

    CERN Document Server

    Soldi, S; Baumgartner, W H; Ponti, G; Shrader, C R; Lubinski, P; Krimm, H A; Mattana, F; Tueller, J

    2013-01-01

    Variability at all observed wavelengths is a distinctive property of AGN. Hard X-rays provide us with a view of the innermost regions of AGN, mostly unbiased by absorption along the line of sight. Swift/BAT offers the unique opportunity to follow, on time scales of days to years and with a regular sampling, the 14-195 keV emission of the largest AGN sample available up to date for this kind of investigation. We study the amplitude of the variations, and their dependence on sub-class and on energy, for a sample of 110 radio quiet and radio loud AGN selected from the BAT 58-month survey. About 80% of the AGN in the sample are found to exhibit significant variability on months to years time scales, radio loud sources being the most variable. The amplitude of the variations and their energy dependence are incompatible with variability being driven at hard X-rays by changes of the absorption column density. In general, the variations in the 14-24 and 35-100 keV bands are well correlated, suggesting a common origin...

  5. Hard X-ray flux variations in AGN from NuSTAR

    CERN Document Server

    Rani, Priyanka

    2016-01-01

    We present here our results on the hour like time scale X-ray flux variations in a sample of active galactic nuclei using data from the Nuclear Spectroscopic Telescope Array (NuSTAR). We find that in the 3-79 keV band, BL Lacs are more variable than flat spectrum radio quasars and Seyfert galaxies. Among Seyferts, Seyfert 2s are more variable than Seyfert 1s. Also, radio-loud quasars are more variable in the hard (10-79 keV) band than the soft (3-10 keV) band while, Seyfert galaxies tend to show more variations in the soft band relative to the hard band.

  6. X-ray Radiation Hardness of Fully-Depleted SOI MOSFETs and Its Improvement

    CERN Document Server

    Kurachi, Ikuo; Kasai, Hiroki; Mochizuki, Marie; Okihara, Masao; Hatsui, Takaki; Hara, Kazuhiko; Arai, Yasuo

    2015-01-01

    X-ray radiation hardness of FD-SOI n- and p-MOSFET has been investigated. After 1.4 kGy(Si) irradiation, 15% drain current increase for n-MOSFET and 20% drain current decrease for p-MOSFET are observed. From analysis of gmmax-Vsub, the major cause of n-MOSFET drain current change is the generated positive charge in BOX. On the other hand, the major cause of p-MOSFET drain current change is the radiation induced gate channel modulation by the generated positive charge in sidewall spacer. It is confirmed that the p-MOSFET drain current change is improved by higher PLDD dose. Thinner BOX is also proposed for further radiation hardness improvement.

  7. An X-ray Imaging System for Hard-to-Reach Facility Diagnosis Using Femtosecond Laser-Plasma

    Science.gov (United States)

    Oishi, Yuji; Nayuki, Takuya; Nakajima, Chikahito; Fujii, Takashi; Zhidkov, Alexei; Nemoto, Koshichi

    2010-04-01

    For hard-to-reach facility diagnosis, a radiographic testing system that consists of a compact laser-plasma X-ray (LPX) generator and a compact X-ray imaging sensor is shown to be competitive to that based on the isotope imaging. A 1-mm-thick CsI charge-coupled device (CCD) sensor supplied with a cooling system was developed to tolerate a long X-ray exposition. Even without optimization of X-ray yield from a Ta thin film irradiated by 230 mJ, 70 fs laser pulses, clear X-ray images of a SUS304 pipe (outer diameter 34 mm with 4.5 mm thickness) with an elbow were produced.

  8. Optimization of graded multilayer designs for astronomical x-ray telescopes

    DEFF Research Database (Denmark)

    Mao, P.H.; Harrison, F.A.; Windt, D.L.;

    1999-01-01

    We developed a systematic method for optimizing the design of depth-graded multilayers for astronomical hard-x-ray and soft-gamma-ray telescopes based on the instrument's bandpass and the field of view. We apply these methods to the design of the conical-approximation Wolter I optics employed...... by the balloon-borne High Energy Focusing Telescope, using W/Si as the multilayer materials. In addition, we present optimized performance calculations of mirrors, using other material pairs that are capable of extending performance to photon energies above the W K-absorption edge (69.5 keV), including Pt/C, Ni...

  9. 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...

  10. HEXTE Studies of Sco X-1 Spectra Detections of Hard X-Ray Tails Beyond 200 keV

    CERN Document Server

    D'Amico, F; Rothschild, R E; Peterson, L E; Gruber, D E; Pelling, M R; Tomsick, J A

    2001-01-01

    Using the HEXTE experiment on-board the RXTE satellite, we performed a search for hard X-ray tails in Sco X-1 spectra. We found strong evidence for the presence of such a non-thermal component on several occasions. Using the PCA/RXTE we were able to track the position of the source along the Z diagram, and we observed that the presence of the hard X-ray tail is not confined to a particular region. However, we found a correlation between the power law index of the non-thermal component and the position of the source in the Z diagram, suggesting that the hard X-ray spectrum (i.e., E > 50 keV) becomes flatter as the mass accretion rate increases. We were also able to study the temporal variation of the appearance/absence of the hard X-ray component. With our derived luminosities, we were also able to test the idea that X-ray luminosities can be used to distinguish between X-ray binary systems containing neutron stars and black holes.

  11. First flight of SMASH, the SwRI Miniature Assembly for Solar Hard X-rays

    Science.gov (United States)

    Caspi, Amir; Laurent, Glenn Thomas; Shoffner, Michael; Higuera Caubilla, David; Meurisse, Jeremie; Smith, Kelly; Shih, Albert Y.; Saint-Hilaire, Pascal; DeForest, Craig; Mansour, Nagi N.; Hathaway, David H.

    2016-05-01

    The SwRI Miniature Assembly for Solar Hard X-rays (SMASH) was successfully flown from Antarctica in January (19-30) 2016, as a piggy-back instrument on the Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) high altitude balloon payload. SMASH is a technological demonstration of a new miniaturized hard X-ray (HXR) detector for use on CubeSats and other small spacecraft, including the proposed CubeSat Imaging X-ray Solar Spectrometer (CubIXSS).HXRs are the observational signatures of energetic processes on the Sun, including plasma heating and particle acceleration. One of the goals of CubIXSS will be to address the question of how plasma is heated during solar flares, including the relationship between thermal plasma and non-thermal particles. SMASH demonstrated the space-borne application of the commercial off-the-shelf Amptek X123-CdTe, a miniature cadmium telluride photon-counting HXR spectrometer. The CdTe detector has a physical area of 25 mm^2 and 1 mm fully-depleted thickness, with a ~100 micron Be window; with on-board thermoelectric cooling and pulse pile-up rejection, it is sensitive to solar photons from ~5 to ~100 keV with ~0.5-1.0 keV FWHM resolution. Photons are accumulated into histogram spectra with customizable energy binning and integration time. With modest resource requirements (~1/8 U, ~200 g, ~2.5 W) and low cost (~$10K), the X123-CdTe is an attractive solution for HXR measurements from budget- and resource-limited platforms such as CubeSats. SMASH flew two identical X123-CdTe detectors for redundancy and increased collecting area; the supporting electronics (power, CPU) were largely build-to-print using the Miniature X-ray Solar Spectrometer (MinXSS) CubeSat design.We review the SMASH mission, design, and detector performance during the 12-day Antarctic flight. We present current progress on our data analysis of observed solar flares, and discuss future applications of the space-qualified X123-CdTe detector, including the CubIXSS mission

  12. The radio/X-ray correlation in Cyg X-3 and the nature of its hard spectral state

    CERN Document Server

    Zdziarski, Andrzej A; Pooley, Guy G

    2015-01-01

    We study the radio/X-ray correlation in Cyg X-3. It has been known that the soft and hard X-ray fluxes in the hard spectral state are correlated positively and negatively, respectively, with the radio flux. We show that this implies that the observed $\\sim$2--100 keV flux (which is a fair approximation to the bolometric flux) is completely uncorrelated with the radio flux. We can recover a positive correlation (seen in other sources and expected theoretically) if the soft X-rays are strongly absorbed by a local medium. Then, however, the intrinsic X-ray spectrum of Cyg X-3 in its hard state is relatively soft, similar to that of an intermediate spectral state of black-hole binaries, but not to their true hard state. We also find the radio spectra in the hard state of Cyg X-3 to be hard on average, and the flux distributions of the radio emission and soft X-rays to follow a sum of two log-normal functions.

  13. Improvement of density resolution in short-pulse hard x-ray radiographic imaging using detector stacks

    Science.gov (United States)

    Borm, B.; Gärtner, F.; Khaghani, D.; Neumayer, P.

    2016-09-01

    We demonstrate that stacking several imaging plates (IPs) constitutes an easy method to increase hard x-ray detection efficiency. Used to record x-ray radiographic images produced by an intense-laser driven hard x-ray backlighter source, the IP stacks resulted in a significant improvement of the radiograph density resolution. We attribute this to the higher quantum efficiency of the combined detectors, leading to a reduced photon noise. Electron-photon transport simulations of the interaction processes in the detector reproduce the observed contrast improvement. Increasing the detection efficiency to enhance radiographic imaging capabilities is equally effective as increasing the x-ray source yield, e.g., by a larger drive laser energy.

  14. Hard X-ray morphology of the X1.3 April 25, 2014 partially occulted limb solar flare

    CERN Document Server

    Effenberger, Frederic; Petrosian, Vahe

    2016-01-01

    At hard X-ray energies, the bright footpoint emission from solar flare loops often prevents a detailed analysis of the weaker loop-top source morphology due to the limited dynamic range available for X-ray imaging. Here, we study the X1.3 April 25, 2014 flare with the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI). This partially occulted limb flare allows the analysis of the loop-top emission in isolation. We present results on the flare light curve at different energies, the source morphology from X-ray imaging and a detailed spectral analysis of the different source components by imaging spectroscopy. The loop-top source, a likely site of particle acceleration, shows a clear composition of different emission components. The results indicate the opportunities that detailed imaging of hard X-rays can provide to learn about particle acceleration, transport and heating processes in solar flares.

  15. Recent progress of hard x-ray imaging microscopy and microtomography at BL37XU of SPring-8

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Yoshio, E-mail: yoshio@spring8.or.jp; Takeuchi, Akihisa; Terada, Yasuko; Uesugi, Kentaro [Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), Sayo, Hyogo 679-5198 (Japan); Mizutani, Ryuta [Department of Applied Biochemistry, Tokai University, Hiratsuka, Kanagawa 259-1292 (Japan)

    2016-01-28

    A hard x-ray imaging microscopy and microtomography system is now being developed at the beamline 37XU of SPring-8. In the latest improvement, a spatial resolution of about 50 nm is achieved in two-dimensional imaging at 6 keV x-ray energy using a Fresnel zone plate objective with an outermost zone width of 35 nm. In the tomographic measurement, a spatial resolution of about 100 nm is achieved at 8 keV using an x-ray guide tube condenser optic and a Fresnel zone plate objective with an outermost zone width of 50 nm.

  16. Nonlinear delayed symmetry breaking in a solid excited by hard x-ray free electron laser pulses

    International Nuclear Information System (INIS)

    We have studied the ultrafast changes of electronic states in bulk ZnO upon intense hard x-ray excitation from a free electron laser. By monitoring the transient anisotropy induced in an optical probe beam, we observe a delayed breaking of the initial c-plane symmetry of the crystal that lasts for several picoseconds. Interaction with the intense x-ray pulses modifies the electronic state filling in a manner inconsistent with a simple increase in electronic temperature. These results may indicate a way to use intense ultrashort x-ray pulses to investigate high-energy carrier dynamics and to control certain properties of solid-state materials

  17. 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.

  18. On the X-ray and optical properties of the Be star HD 110432: a very hard-thermal X-ray emitter

    Science.gov (United States)

    Lopes de Oliveira, R.; Motch, C.; Smith, M. A.; Negueruela, I.; Torrejón, J. M.

    2007-11-01

    HD 110432 is the first proposed, and best studied, member of a growing group of Be stars with X-ray properties similar to γ Cas. These stars exhibit hard-thermal X-rays that are variable on all measurable timescales. This emission contrasts with the soft emission of “normal" massive stars and with the non-thermal emission of all well known Be/X-ray binaries - so far, all Be + neutron star systems. In this work we present X-ray spectral and timing properties of HD 110432 from three XMM-Newton observations in addition to new optical spectroscopic observations. Like γ Cas, the X-rays of HD 110432 appear to have a thermal origin, as supported by strongly ionized Fe XXV and Fe XXVI lines detected in emission. A fluorescent iron feature at 6.4 keV is present in all observations, while the Fe XXVI Lyβ line is present in two of them. Its X-ray spectrum, complex and time variable, is well described in each observation by three thermal plasmas with temperatures ranging between 0.2-0.7, 3-6, and 16-37 keV. Thus, HD 110432 has the hottest thermal plasma of any known Be star. A sub-solar iron abundance (~0.3-0.5 ×Z_Fe,⊙) is derived for the hottest plasma, while lines of less excited ions at longer wavelengths are consistent with solar abundances. The star has a moderate 0.2-12 keV luminosity of ~5×1032 erg s-1. The intensity of the X-ray emission is strongly variable. Recurrent flare-like events on time scales as short as ~10 s are superimposed over a basal flux which varies on timescales of ~5-10×103 s, followed by similarly rapid hardness variabilities. There is no evidence for coherent oscillations, and an upper limit of ~2.5% is derived on the pulsed fraction for short pulsations from 0.005 to 2.5 Hz. In the optical region the strong and quasi-symmetrical profile of the Hα line (EW ~ -60 Å) as well as the detection of several metallic lines in emission strongly suggest a dense and/or large circumstellar disk. Also, the double-peaked profiles of metallic lines

  19. Optical constants in the hard X-ray/Soft gamma ray range of selected materials for multilayer reflectors

    DEFF Research Database (Denmark)

    Cooper-Jensen, Carsten P.; Romaine, S.; Bruni, R.;

    2007-01-01

    Future Astrophysics missions operating in the hard X-ray/Soft Gamma ray range is slated to carry novel focusing telescopes based on the use of depth graded multilayer reflectors. Current design studies show that, at the foreseen focal lengths, it should be feasible to focus X-rays at energies...... Synchrotron Light Source in Brookhaven and compare these to results obtained previously up to 180 keV of some of the same materials at the European Synchrotron Radiation Facility in Grenoble....

  20. The Global Implications of the Hard X-ray Excess in Type 1 AGN

    CERN Document Server

    Tatum, M M; Miller, L; Reeves, J N

    2012-01-01

    Recent evidence for a strong 'hard excess' of flux at energies > 20 keV in some Suzaku observations of type 1 Active Galactic Nuclei (AGN) has motivated an exploratory study of the phenomenon in the local type 1 AGN population. We have selected all type 1 AGN in the Swift Burst Alert Telescope (BAT) 58-month catalog and cross-correlated them with the holdings of the Suzaku public archive. We find the hard excess phenomenon to be a ubiquitous property of type 1 AGN. Taken together, the spectral hardness and equivalent width of Fe K alpha emission are consistent with reprocessing by an ensemble of Compton-thick clouds that partially cover the continuum source. In the context of such a model, ~ 80 % of the sample has a hardness ratio consistent with > 50% covering of the continuum by low-ionization, Compton-thick gas. More detailed study of the three hardest X-ray spectra in our sample reveal a sharp Fe K absorption edge at ~ 7 keV in each of them, indicating that blurred reflection is not responsible for the ve...

  1. Swift J2218.4+1925: a new hard X-ray selected Polar observed with XMM-Newton

    CERN Document Server

    Bernardini, Federico; Mukai, Koji; Falanga, Maurizio

    2014-01-01

    Swift J2218.4+1925, a hard X-ray source detected by Swift BAT, has been proposed as a candidate magnetic cataclysmic variable of the polar type from optical spectroscopy. Using XMM-Newton we perform detailed timing and spectral analysis with simultaneous X-ray ($0.3-10$ keV) and optical B band data. We complement the spectral study with archival hard X-ray (14-70 keV) spectra collected by Swift BAT as well as with optical, near and mid-infrared photometry from $SDSS$, $2MASS$ and $WISE$ archive, respectively. A strong periodic X-ray signal at 2.16 h, consistent with the recently determined spectroscopic orbital period, adds Swift J2218.4+1925 to the small group of hard X-ray polars and locates it at the low edge of the orbital period gap. The X-ray pulse profile shows the typical bright and faint phases seen in polars ($\\sim 70%$ and $\\sim 30%$ of the orbit, respectively). A pronounced dip centred on the bright phase is also detected. It is stronger at lower energies and is mainly produced by photoelectric ab...

  2. On-orbit calibration status of the hard x-ray detector (HXD) onboard Suzaku

    Science.gov (United States)

    Nishino, S.; Fukazawa, Y.; Mizuno, T.; Takahashi, H.; Hayashi, K.; Hiragi, K.; Mizuno, M.; Yamada, S.; Kawaharada, M.; Kokubun, M.; Nakazawa, K.; Watanabe, S.; Tanaka, T.; Terada, Y.

    2010-07-01

    Hard X-ray Detector (HXD) onboard Suzaku, the Japanese 5th X-ray observatory, consists of 64 PIN photo diodes with 2 mm thickness (10-70 keV) and 16 phoswich detectors using 5 mm-thick GSO scintillators and BGO active collimators (40-600 keV), and these are surrounded by 20 units of BGO Active shields. All the detector units have been working well with no significant troubles in four and a half years since the launch on July 2005, and given many important scientific results. In this paper, we report the recent status of on-orbit calibrations for PIN/GSO detectors. For the PIN, analog/digital threshold levels of both in-orbit and on-ground are raised up to avoid the increasing noise events due to in-orbit radiation damage. For the GSO, the accuracy of the energy scale and modeling of gain variations are improved, and newly calibrated data set including background files and response matrices are released on April 2010.

  3. The LCLS variable-energy hard X-ray single-shot spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Rich, David; Zhu, Diling; Turner, James; Zhang, Dehong; Hill, Bruce; Feng, Yiping

    2016-01-01

    The engineering design, implementation, operation and performance of the new variable-energy hard X-ray single-shot spectrometer (HXSSS) for the LCLS free-electron laser (FEL) are reported. The HXSSS system is based on a cylindrically bent Si thin crystal for dispersing the incident polychromatic FEL beam. A spatially resolved detector system consisting of a Ce:YAG X-ray scintillator screen, an optical imaging system and a low-noise pixelated optical camera is used to record the spectrograph. The HXSSS provides single-shot spectrum measurements for users whose experiments depend critically on the knowledge of the self-amplified spontaneous emission FEL spectrum. It also helps accelerator physicists for the continuing studies and optimization of self-seeding, various improved mechanisms for lasing mechanisms, and FEL performance improvements. The designed operating energy range of the HXSSS is from 4 to 20 keV, with the spectral range of order larger than 2% and a spectral resolution of 2 × 10-5or better. Those performance goals have all been achieved during the commissioning of the HXSSS.

  4. The LCLS variable-energy hard X-ray single-shot spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Rich, David; Zhu, Diling; Turner, James; Zhang, Dehong; Hill, Bruce; Feng, Yiping

    2016-01-01

    The engineering design, implementation, operation and performance of the new variable-energy hard X-ray single-shot spectrometer (HXSSS) for the LCLS free-electron laser (FEL) are reported. The HXSSS system is based on a cylindrically bent Si thin crystal for dispersing the incident polychromatic FEL beam. A spatially resolved detector system consisting of a Ce:YAG X-ray scintillator screen, an optical imaging system and a low-noise pixelated optical camera is used to record the spectrograph. The HXSSS provides single-shot spectrum measurements for users whose experiments depend critically on the knowledge of the self-amplified spontaneous emission FEL spectrum. It also helps accelerator physicists for the continuing studies and optimization of self-seeding, various improved mechanisms for lasing mechanisms, and FEL performance improvements. The designed operating energy range of the HXSSS is from 4 to 20 keV, with the spectral range of order larger than 2% and a spectral resolution of 2 × 10-5or better. Those performance goals have all been achieved during the commissioning of the HXSSS.

  5. INTEGRAL 11-year hard X-ray survey above 100 keV

    CERN Document Server

    Krivonos, Roman A; Lutovinov, Alexander A; Revnivtsev, Mikhail G; Churazov, Eugene M; Sunyaev, Rashid A

    2014-01-01

    We present results of all sky survey, performed with data acquired by the IBIS telescope onboard the INTEGRAL observatory over eleven years of operation, at energies above 100 keV. A catalogue of detected sources includes 132 objects. The statistical sample detected on the time-averaged 100-150 keV map at a significance above 5 sigma contains 88 sources: 28 AGNs, 38 LMXBs, 10 HMXBs and 12 rotation-powered young X-ray pulsars. The catalogue includes also 15 persistent sources, which were registered with the significance 4 sigma 12 sigma) in the 17-60 keV energy band. All sources from these two groups are known X-ray emitters, that means that the catalogue has 100% purity in respect to them. Additionally, 29 sources were found in different time intervals. In the context of the survey we present a hardness ratio of galactic and extragalactic sources, a LMXBs longitudinal asymmetry and a number-flux relation for non-blazar AGNs. At higher energies, in the 150-300 keV energy band, 25 sources have been detected wit...

  6. Space and time resolved emission of hard X-rays from a plasma focus

    Science.gov (United States)

    Harries, W. L.; Lee, J. H.; Mcfarland, D. R.

    1978-01-01

    The X-ray emission from focused plasmas was observed with an image converter camera in the streak and framing modes. Use of a very high gain image intensifier enabled weak hard X-ray emission (above 25 keV) to be recorded. The use of an admixture of higher atomic number into the deuterium was avoided, and the role of the vapor from the anode surface could be discerned. The recorded bremsstrahlung emission seemed to be from a metallic plasma of copper released from the anode surface by bombardment from an intense electron beam. The intensity of emission was determined by the density of copper and the density and energy of the electron beam. The main emission recorded occurred several 100 nsec after the focus was over, which implies that the electric fields driving the beam existed for this duration. It is suggested that the fields were created by annihilation of magnetic flux for a time much longer than the focus duration.

  7. Scattered hard X-ray and γ-ray generation from a chromatic electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, J. E. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Welch, D. R.; Miller, C. L. [Voss Scientific, Albuquerque, New Mexico 87108 (United States)

    2015-11-14

    An array of photon diagnostics has been deployed on a high power relativistic electron beam diode. Electrons are extracted through a 17.8 cm diode from the surface discharge of a carbon fiber velvet cathode with a nominal diode voltage of 3.8 MV. <10% of the 100 ns electron pulse is composed of off energy electrons (1–3 MeV) accelerated during the rise and fall of the pulse that impact the stainless steel beam pipe and generate a Bremsstrahlung spectrum of 0.1–3 MeV photons with a total count of 10{sup 11}. The principal objective of these experiments is to quantify the electron beam dynamics and spatial dynamics of the hard X-ray and γ-ray flux generated in the diode region. A qualitative comparison of experimental and calculated results are presented, including time and energy resolved electron beam propagation and scattered photon measurements with X-ray PIN diodes and a photomultiplier tube indicating a dose dependence on the diode voltage >V{sup 4} and detected photon counts of nearly 10{sup 6} at a radial distance of 1 m which corresponds to dose ∼40 μrad at 1 m.

  8. Hard X-ray Luminosity Function of Tidal Disruption Events: First Results from MAXI Extragalactic Survey

    CERN Document Server

    Kawamuro, Taiki; Shidatsu, Megumi; Hori, Takafumi; Kawai, Nobuyuki; Negoro, Hitoshi; Mihara, Tatehiro

    2016-01-01

    We derive the first hard X-ray luminosity function (XLF) of stellar tidal disruption events (TDEs) by supermassive black holes (SMBHs), which gives an occurrence rate of TDEs per unit volume as a function of peak luminosity and redshift, utilizing an unbiased sample observed by the Monitor of All-sky X-ray Image (MAXI). On the basis of the light curves characterized by a power-law decay with an index of $-5/3$, a systematic search using the MAXI data in the first 37 months detected four TDEs, all of which have been found in the literature. To formulate the TDE XLF, we consider the mass function of SMBHs, that of disrupted stars, the specific TDE rate as a function of SMBH mass, and the fraction of TDEs with relativistic jets. We perform an unbinned maximum likelihood fit to the MAXI TDE list and check the consistency with the observed TDE rate in the ROSAT all sky survey. The results suggest that the intrinsic fraction of the jet-accompanying events is $0.0007$--$34\\%$. We confirm that at $z \\lesssim 1.5$ the...

  9. Quantitative spectromicroscopy from inelastically scattered photoelectrons in the hard X-ray range

    Science.gov (United States)

    Renault, O.; Zborowski, C.; Risterucci, P.; Wiemann, C.; Grenet, G.; Schneider, C. M.; Tougaard, S.

    2016-07-01

    We demonstrate quantitative, highly bulk-sensitive x-ray photoelectron emission microscopy by analysis of inelastically scattered photoelectrons in the hard X-ray range, enabling elemental depth distribution analysis in deeply buried layers. We show results on patterned structures used in electrical testing of high electron mobility power transistor devices with an epitaxial Al0.25Ga0.75N channel and a Ti/Al metal contact. From the image series taken over an energy range of up to 120 eV in the Ti 1s loss feature region and over a typical 100 μm field of view, one can accurately retrieve, using background analysis together with an optimized scattering cross-section, the Ti depth distribution from 14 nm up to 25 nm below the surface. The method paves the way to multi-elemental, bulk-sensitive 3D imaging and investigation of phenomena at deeply buried interfaces and microscopic scales by photoemission.

  10. Scattered hard X-ray and γ-ray generation from a chromatic electron beam

    International Nuclear Information System (INIS)

    An array of photon diagnostics has been deployed on a high power relativistic electron beam diode. Electrons are extracted through a 17.8 cm diode from the surface discharge of a carbon fiber velvet cathode with a nominal diode voltage of 3.8 MV. <10% of the 100 ns electron pulse is composed of off energy electrons (1–3 MeV) accelerated during the rise and fall of the pulse that impact the stainless steel beam pipe and generate a Bremsstrahlung spectrum of 0.1–3 MeV photons with a total count of 1011. The principal objective of these experiments is to quantify the electron beam dynamics and spatial dynamics of the hard X-ray and γ-ray flux generated in the diode region. A qualitative comparison of experimental and calculated results are presented, including time and energy resolved electron beam propagation and scattered photon measurements with X-ray PIN diodes and a photomultiplier tube indicating a dose dependence on the diode voltage >V4 and detected photon counts of nearly 106 at a radial distance of 1 m which corresponds to dose ∼40 μrad at 1 m

  11. Toward TW-Level, Hard X-Ray Pulses at LCLS

    Energy Technology Data Exchange (ETDEWEB)

    Fawley, W.M.; Frisch, J.; Huang, Z.; Jiao, Y.; Nuhn, H.-D.; /SLAC; Pellegrini, C.; /SLAC /UCLA; Reiche, S.; /PSI, Villigen; Wu, J,; /SLAC

    2011-12-13

    Coherent diffraction imaging of complex molecules such as proteins requires a large number (e.g., {approx} 10{sup 13}/pulse) of hard X-ray photons within a time scale of {approx} 10 fs or less. This corresponds to a peak power of {approx} 1 TW, much larger than that currently generated by LCLS or other proposed X-ray free electron lasers (FELs). We study the feasibility of producing such pulses using a LCLS-like, low charge electron beam, as will be possible in the LCLS-II upgrade project, employing a configuration beginning with a SASE amplifier, followed by a 'self-seeding' crystal monochromator, and finishing with a long tapered undulator. Our results suggest that TW-level output power at 8.3 keV is possible from a total undulator system length around 200 m. In addition power levels larger than 100 GW are generated at the third harmonic. We present a tapering strategy that extends the original 'resonant particle' formalism by optimizing the transport lattice to maximize optical guiding and enhance net energy extraction. We discuss the transverse and longitudinal coherence properties of the output radiation pulse and the expected output pulse energy sensitivity, both to taper errors and to power fluctuations on the monochromatized SASE seed.

  12. Compton Heating of the Intergalactic Medium by the Hard X-ray Background

    CERN Document Server

    Madau, P; Madau, Piero; Efstathiou, George

    1999-01-01

    High-resolution hydrodynamics simulations of the Ly-alpha forest in cold dark matter dominated cosmologies appear to predict line widths that are substantially narrower than those observed. Here we point out that Compton heating of the intergalactic gas by the hard X-ray background (XRB), an effect neglected in all previous investigations, may resolve this discrepancy. The rate of gain in thermal energy by Compton scattering will dominate over the energy input from hydrogen photoionization if the XRB energy density is 0.2x/ times higher than the energy density of the UV background at a given epoch, where x is the hydrogen neutral fraction in units of 1e-6 and is the mean X-ray photon energy in units of m_ec^2. The numerical integration of the time-dependent rate equations shows that the intergalactic medium approaches a temperature of about 20,000 K at z>3 in popular models for the redshift evolution of the extragalactic background radiation. The importance of Compton heating can be tested experimentally by ...

  13. A comprehensive analysis of the hard X-ray spectra of bright Seyfert galaxies

    CERN Document Server

    Lubinski, P; Gibaud, L; Paltani, S; Papadakis, I E; Ricci, C; Soldi, S; Türler, M; Walter, R; Zdziarski, A A

    2016-01-01

    Hard X-ray spectra of 28 bright Seyfert galaxies observed with INTEGRAL were analyzed together with the X-ray spectra from XMM-Newton, Suzaku and RXTE. These broad-band data were fitted with a model assuming a thermal Comptonization as a primary continuum component. We tested several model options through a fitting of the Comptonized continuum accompanied by a complex absorption and a Compton reflection. Both the large data set used and the model space explored allowed us to accurately determine a mean temperature kTe of the electron plasma, the Compton parameter y and the Compton reflection strength R for the majority of objects in the sample. Our main finding is that a vast majority of the sample (20 objects) is characterized by kTe 200 keV. The median kTe for entire sample is 48(-14,+57) keV. The distribution of the y parameter is bimodal, with a broad component centered at ~0.8 and a narrow peak at ~1.1. A complex, dual absorber model improved the fit for all data sets, compared to a simple absorption mo...

  14. Achromatic nested Kirkpatrick-Baez mirror optics for hard X-ray nanofocusing.

    Science.gov (United States)

    Liu, Wenjun; Ice, Gene E; Assoufid, Lahsen; Liu, Chian; Shi, Bing; Khachatryan, Ruben; Qian, Jun; Zschack, Paul; Tischler, Jonathan Z; Choi, J Y

    2011-07-01

    The first test of nanoscale-focusing Kirkpatrick-Baez (KB) mirrors in the nested (or Montel) configuration used at a hard X-ray synchrotron beamline is reported. The two mirrors are both 40 mm long and coated with Pt to produce a focal length of 60 mm at 3 mrad incident angle, and collect up to a 120 µm by 120 µm incident X-ray beam with maximum angular acceptance of 2 mrad and a broad bandwidth of energies up to 30 keV. In an initial test a focal spot of about 150 nm in both horizontal and vertical directions was achieved with either polychromatic or monochromatic beam. The nested mirror geometry, with two mirrors mounted side-by-side and perpendicular to each other, is significantly more compact and provides higher demagnification than the traditional sequential KB mirror arrangement. Ultimately, nested mirrors can focus larger divergence to improve the diffraction limit of achromatic optics. A major challenge with the fabrication of the required mirrors is the need for near-perfect mirror surfaces near the edge of at least one of the mirrors. Special polishing procedures and surface profile coating were used to preserve the mirror surface quality at the reflecting edge. Further developments aimed at achieving diffraction-limited focusing below 50 nm are underway.

  15. Evidence for intermediate polars as the origin of the Galactic Center hard X-ray emission

    CERN Document Server

    Hailey, Charles J; Perez, Kerstin; Canipe, Alicia M; Hong, Jaesub; Tomsick, John A; Boggs, Steven E; Christensen, Finn E; Craig, William W; Fornasini, Francesca; Grindlay, Jonathan E; Harrison, Fiona A; Nynka, Melania; Rahoui, Farid; Stern, Daniel; Zhang, Shuo; Zhang, William W

    2016-01-01

    Recently, unresolved hard (20-40 keV) X-ray emission has been discovered within the central 10 pc of the Galaxy, possibly indicating a large population of intermediate polars (IPs). Chandra and XMM-Newton measurements in the surrounding ~50 pc imply a much lighter population of IPs with $\\langle M_{\\rm WD} \\rangle \\approx 0.5 M_\\odot$. Here we use broad-band NuSTAR observations of two IPs: TV Columbae, which has a fairly typical but widely varying reported mass of $M_{\\rm WD} \\approx 0.5-1.0 M_\\odot$, and IGR J17303-0601, with a heavy reported mass of $M_{\\rm WD} \\approx 1.0-1.2 M_\\odot$. We investigate how varying spectral models and observed energy ranges influence estimated white dwarf mass. Observations of the inner 10 pc can be accounted for by IPs with $\\langle M_{\\rm WD} \\rangle \\approx 0.9 M_\\odot$, consistent with that of the CV population in general, and the X-ray observed field IPs in particular. The lower mass derived by Chandra and XMM-Newton appears to be an artifact of narrow energy band fittin...

  16. The influence of albedo on the size of hard X-ray flare sources

    Science.gov (United States)

    Battaglia, M.; Kontar, E. P.; Hannah, I. G.

    2011-02-01

    Context. Hard X-rays from solar flares are an important diagnostic of particle acceleration and transport in the solar atmosphere. However, any observed X-ray flux from on-disc sources is composed of direct emission plus Compton backscattered photons (albedo). This affects both the observed spectra and images and the physical quantities derived from them, such as the spatial and spectral distributions of accelerated electrons or characteristics of the solar atmosphere (e.g. density). Aims: We propose a new indirect method to measure albedo and to infer the directivity of X-rays in imaging using RHESSI data. We describe this method and demonstrate its application to a compact disc event observed with RHESSI. Methods: Visibility forward fitting is used to determine the size (second moment) of a disc event observed by RHESSI as a function of energy. Using a Monte Carlo simulation code of photon transport in the chromosphere, maps for different degrees of downward directivity and true source sizes are computed. The resulting sizes from the simulated maps are compared with the sizes from the observations to find limits on the true source size and the directivity. Results: The observed full width half maximum of the source varies in size between 7.4 arcsec and 9.1 arcsec with the maximum between 30 and 40 keV. Such behaviour is expected in the presence of albedo and is found in the simulations. The uncertainties in the data are not small enough to make unambiguous statements about the true source size and the directivity simultaneously. However, a source size smaller than 6 arcsec is improbable for modest directivities, and the true source size is likely to be around 7 arcsec for small directivities. Conclusions: While it is difficult to image the albedo patch directly, the effect of backscattered photons on the observed source size can be estimated. This is demonstrated here on observations for the first time. The increase in source size caused by albedo has to be

  17. Hard X-ray diffraction enhanced imaging only using two crystals

    Institute of Scientific and Technical Information of China (English)

    LI Gang; WANG Nan; WU Ziyu

    2004-01-01

    Different configurations for the monochromator crystals and the analyzer crystals have been used in hard X-ray diffraction enhanced imaging (DEI) methods to overcome the complex task to adjust each of them to the ideal position. Here we present a very compact DEI configuration, and preliminary results of experiments performed at the Beijing Synchrotron Radiation Facility (BSRF) using only two crystals: the first one acting as monochromator and the second one as analyzer in the Bragg geometry. Refraction contrast images characterized by high contrast and spatial resolution are obtained and compared with absorption images. Differences among these images will be outlined and discussed emphasizing the potential capabilities of this very simple layout that guarantees a high transmission efficiency.

  18. Photon Temperatures of Hard X-Ray Emission of LHCD Plasmas in HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    Jawad YOUNIS; WAN Baonian; CHEN Zhongyong; LIN Shiyao; SHI Yuejiang; SHAN Jiafang; LIU Fukun

    2008-01-01

    A detailed study of photon temperatures (Tph) of hard X-ray emission in lower hybrid current drive (LHCD) plasmas is presented.The photon temperature increases with the increase in plasma current and decreases with the increase in plasma density.In lower hybrid power and phase scanning experiments;there is no appreciable change in the photon temperature.The numerical results based on ray-tracing calculation and Fokker-Planck solver gives reasonable explanation for the experimental observation.Both experimental and numerical results reveal that the photon temperature depends mainly on global effects of the fast electron population,synergy between the fast electron and the loop voltage and the Coulomb slowing down.

  19. Tunable hard X-ray spectrometer utilizing asymmetric planes of a quartz transmission crystal.

    Science.gov (United States)

    Seely, John F; Henins, Albert; Feldman, Uri

    2016-05-01

    A Cauchois type hard x-ray spectrometer was developed that utilizes the (301) diffraction planes at an asymmetric angle of 23.51° to the normal to the surface of a cylindrically curved quartz transmission crystal. The energy coverage is tunable by rotating the crystal and the detector arm, and spectra were recorded in the 8 keV to 20 keV range with greater than 2000 resolving power. The high resolution results from low aberrations enabled by the nearly perpendicular angle of the diffracted rays with the back surface of the crystal. By using other asymmetric planes of the same crystal and rotating to selected angles, the spectrometer can operate with high resolution up to 50 keV.

  20. Expected Hard X-Ray and Soft Gamma-Ray from Supernovae

    CERN Document Server

    Maeda, Keiichi; Bamba, Aya

    2014-01-01

    High energy emissions from supernovae (SNe), originated from newly formed radioactive species, provide direct evidence of nucleosynthesis at SN explosions. However, observational difficulties in the MeV range have so far allowed the signal detected only from the extremely nearby core-collapse SN 1987A. No solid detection has been reported for thermonuclear SNe Ia, despite the importance of the direct confirmation of the formation of 56Ni, which is believed to be a key ingredient in their nature as distance indicators. In this paper, we show that the new generation hard X-ray and soft gamma-ray instruments, on board Astro-H and NuStar, are capable of detecting the signal, at least at a pace of once in a few years, opening up this new window for studying SN explosion and nucleosynthesis.

  1. INTEGRAL discovered a new hard X-ray source: IGRJ17511-3057

    DEFF Research Database (Denmark)

    Baldovin, C.; Kuulkers, E.; Ferrigno, C.;

    2009-01-01

    During the latest observations of the Galactic Bulge monitoring (see ATel #438), carried out between 2009-09-12 03:21:34 and 2009-09-12 05:27:22 (UTC), INTEGRAL discovered a new bright hard X-ray source, which we designate IGRJ17511-3057. The source is detected in the INTEGRAL/IBIS mosaic image w...... by a single power-law with photon index 2.0+/-0.2. The source flux is 5.7e-10 erg/cm2/s in the 3-20 keV energy band and 4.8e-10 erg/cm2/s in the 20-100 keV energy band....

  2. Spatially resolved hard X-ray polarization in solar flares: effects of Compton scattering and bremsstrahlung

    CERN Document Server

    Jeffrey, Natasha

    2011-01-01

    This paper aims to study the polarization of hard X-ray (HXR) sources in the solar atmosphere, including Compton backscattering of photons in the photosphere (the albedo effect) and the spatial distribution of polarization across the source. HXR photon polarization and spectra produced via electron-ion bremsstrahlung are calculated from electron distributions typical for solar flares. Compton scattering and photoelectric absorption are then modelled using Monte Carlo simulations of photon transport in the photosphere. Polarization maps across HXR sources (primary and albedo components) for each of the modelled electron distributions are calculated at various source locations from the solar centre to the limb. We show that Compton scattering produces a distinct polarization variation across the albedo patch at peak albedo energies of 20-50 keV for all anisotropies modelled. The results show that there are distinct spatial polarization changes in both the radial and perpendicular to radial directions across the...

  3. NuSTAR hard x-ray optics design and performance

    DEFF Research Database (Denmark)

    Koglin, J. E.; An, H.; Blaedel, K. L.;

    2009-01-01

    The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA satellite mission scheduled for launch in 2011. Using focusing optics with multilayer coating for enhanced reflectivity of hard X-rays (6-79 keV), NuSTAR will provide a combination of clarity, sensitivity and spectral resolution...... surpassing the largest observatories in this band by orders of magnitude. This advance will allow NuSTAR to test theories of how heavy elements are born, discover collapsed stars and black holes on all scales and explore the most extreme physical environments. We will present an overview of the NuSTAR optics...... design and production process and detail the optics performance....

  4. Solar Hard X-ray Source Sizes in a Beam-Heated and Ionised Chromosphere

    CERN Document Server

    O'Flannagain, A; Gallagher, P T

    2014-01-01

    Solar flare hard X-rays (HXRs) are produced as bremsstrahlung when an accelerated population of electrons interacts with the dense chromospheric plasma. HXR observations presented by using the Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) have shown that HXR source sizes are 3-6 times more extended in height than those predicted by the standard collisional thick target model (CTTM). Several possible explanations have been put forward including the multi-threaded nature of flare loops, pitch-angle scattering, and magnetic mirroring. However, the nonuniform ionisation (NUI) structure along the path of the electron beam has not been fully explored as a solution to this problem. Ionised plasma is known to be less effective at producing nonthermal bremsstrahlung HXRs when compared to neutral plasma. If the peak HXR emission was produced in a locally ionised region within the chromosphere, the intensity of emission will be preferentially reduced around this peak, resulting in a more extended source. Due to...

  5. A hard x-ray KB-FZP microscope for tomography with sub-100-nm resolution

    Energy Technology Data Exchange (ETDEWEB)

    Rau, C.; Crecea, V.; Richter, C.-P.; Peterson, K.M.; Jemian, P.R.; Neuhausler, U.; Schneider, G.; Yu, X.; Braun, P.V.; Chiang, T.-C.; Robinson, I.K. (UIUC); (NWU); (Bessy); (U Bielefeld)

    2008-08-04

    An instrument for high-resolution imaging and tomography has been built at the APS beamline 34 ID-C, Argonne National Laboratory. In-line phase contrast tomography can be performed with micrometer resolution. For imaging and tomography with resolution better than 100nm a hard X-ray microscope has been integrated to the instrument. It works with a Kirkpatrick-Baez (KB) mirror as condenser and a Fresnel-Zone plate (FZP) as an objective lens. 50 nm-features have been resolved in a Nickel structure operating the microscope at a photon energy of 9keV. Phase objects with negligible absorption contrast have been imaged. Tomography scans were performed on photonic crystals.

  6. Bulk electronic structure of FeRh undergoing metamagnetic transition via hard x-ray photoemission

    Science.gov (United States)

    Gray, Alexander; Cooke, David; Kruger, Peter; Bordel, Catherine; Fullerton, Eric; Ueda, Shigenori; Kobayashi, Keisuke; Hellman, Frances; Fadley, Charles

    2012-02-01

    In this study changes in the electronic structure accompanying a temperature-induced metamagnetic transition from anti-ferromagnetic to ferromagnetic order are investigated in strained epitaxial FeRh thin films via valence-band and core-level hard x-ray photoelectron spectroscopy with a photon energy of 6 keV. At such high photon energy, the resulting inelastic mean-free paths of the photoemitted electrons and therefore the average probing depths are on the order of 60 å, corresponding to about 20 unit cells and ensuring truly bulk-sensitive measurement. Clear differences between the AFM and FM states are observed across the entire valence-band spectrum and these are well reproduced using density functional theory. Changes in the Fe 2p core-levels of Fe are also observed and interpreted using Anderson impurity model calculations. These results suggest that significant electronic structure changes are involved in this AFM-FM transition.

  7. Background and Imaging Simulations for the Hard X-Ray Camera of the MIRAX Mission

    CERN Document Server

    Castro, Manuel; Penacchioni, Ana; D'Amico, Flavio; Sacahui, Rodrigo

    2016-01-01

    We report the results of detailed Monte Carlo simulations of the performance expected both at balloon altitudes and at the probable satellite orbit of a hard X-ray coded-aperture camera being developed for the {\\it MIRAX\\/} mission. Based on a thorough mass model of the instrument and detailed specifications of the spectra and angular dependence of the various relevant radiation fields at both the stratospheric and orbital environments, we have used the well-known package GEANT4 to simulate the instrumental background of the camera. We also show simulated images of source fields to be observed and calculated the detailed sensitivity of the instrument in both situations. The results reported here are especially important to researchers in this field considering that we provide important information, not easily found in the literature, on how to prepare input files and calculate crucial instrumental parameters to perform GEANT4 simulations for high-energy astrophysics space experiments.

  8. Background and imaging simulations for the hard X-ray camera of the MIRAX mission

    Science.gov (United States)

    Castro, M.; Braga, J.; Penacchioni, A.; D'Amico, F.; Sacahui, R.

    2016-07-01

    We report the results of detailed Monte Carlo simulations of the performance expected both at balloon altitudes and at the probable satellite orbit of a hard X-ray coded-aperture camera being developed for the Monitor e Imageador de RAios X (MIRAX) mission. Based on a thorough mass model of the instrument and detailed specifications of the spectra and angular dependence of the various relevant radiation fields at both the stratospheric and orbital environments, we have used the well-known package GEANT4 to simulate the instrumental background of the camera. We also show simulated images of source fields to be observed and calculated the detailed sensitivity of the instrument in both situations. The results reported here are especially important to researchers in this field considering that we provide important information, not easily found in the literature, on how to prepare input files and calculate crucial instrumental parameters to perform GEANT4 simulations for high-energy astrophysics space experiments.

  9. Effect of precipitation on diagnostics for electron trap models of solar hard X-ray bursts

    Energy Technology Data Exchange (ETDEWEB)

    MacKinnon, A.L.; Brown, J.C.; Trottet, G.; Vilmer, N.

    1983-03-01

    Some extended hard X-ray bursts exhibit increasing delays in peak times with photon energy. These delays have been interpreted in terms of the energy dependence of collisional decay time of energetic electrons in a magnetic trap and used to infer the trap density. Here we consider the effect on such analyses of the inevitable collisional precipitation of electrons from the trap to the thick target chromosphere, which has been neglected previously. We find that although precipitation does influence burst time profiles, in particular shortening burst decay times for a given trap density, it has very little effect on the relative delays of burst peak with energy. Consequently values of trap density previously inferred neglecting precipitation should be essentially correct.

  10. Depth-resolved X-ray residual stress analysis in PVD (Ti, Cr) N hard coatings

    CERN Document Server

    Genzel, C

    2003-01-01

    Physical vapour deposition (PVD) of thin hard coatings on TiN basis is usually performed at rather low temperatures (T sub D < 500 C) far from thermal equilibrium, which leads to high intrinsic residual stresses in the growing film. In contrast to the extrinsic thermal residual stresses which can easily be estimated from the difference of the coefficients of thermal expansion between the substrate and the coating, a theoretical prediction of the intrinsic residual stresses is difficult, because their amount as well as their distribution within the film depend in a very complex way on the deposition kinetics. By the example of strongly fibre-textured PVD (Ti, Cr)N coatings which have been prepared under defined variation of the deposition parameters in order to adjust the residual stress distribution within the coatings, the paper compares different X-ray diffraction techniques with respect to their applicability for detecting residual stresses which are non-uniform over the coating thickness. (orig.)

  11. Development of a Hard X-ray focal plane Compton Polarimeter: A compact polarimetric configuration with Scintillators and Si photomultipliers

    CERN Document Server

    Chattopadhyay, T; Goyal, S K; S., Mithun N P; Patel, A R; Shukla, R; Ladiya, T; Shanmugam, M; Patel, V R; Ubale, G P

    2015-01-01

    X-ray polarization measurement of cosmic sources provides two unique parameters namely degree and angle of polarization which can probe the emission mechanism and geometry at close vicinity of the compact objects. Specifically, the hard X-ray polarimetry is more rewarding because the sources are expected to be intrinsically highly polarized at higher energies. With the successful implementation of Hard X-ray optics in NuSTAR, it is now feasible to conceive Compton polarimeters as focal plane detectors. Such a configuration is likely to provide sensitive polarization measurements in hard X-rays with a broad energy band. We are developing a focal plane hard X-ray Compton polarimeter consisting of a plastic scintillator as active scatterer surrounded by a cylindrical array of CsI(Tl) scintillators. The scatterer is 5 mm diameter and 100 mm long plastic scintillator (BC404) viewed by normal PMT. The photons scattered by the plastic scatterer are collected by a cylindrical array of 16 CsI(Tl) scintillators (5 mm x...

  12. 6 MeV storage ring dedicated to hard X-ray imaging and far-infrared spectroscopy

    Indian Academy of Sciences (India)

    M M Haque; A Moon; T Hirai; H Yamada

    2011-02-01

    The tabletop storage ring, 6 MeV MIRRORCLE, is dedicated to hard X-ray imaging as well as far-infrared (FIR) spectroscopy. In spite of low electron energy, the 6 MeV MIRRORCLE generates hard X-rays ranging from 10 keV up to its electron energy and milliwatt order submillimetre range FIR rays. Bremsstrahlung is the mechanism for the hard X-ray generation. Images produced with 11 × geometrical magnification display a sharply enhanced edge effect when generated using a 25 mm rod electron target. Bright far-infrared is generated in the same way using a conventional synchrotron light source, but with MIRRORCLE the spectral flux is found to be ∼ 1000 times greater than that of a standard thermal source. Partially coherent enhancement is observed in the case of FIR output.

  13. A `high-hard' outburst of the black hole X-ray binary GS 1354-64

    Science.gov (United States)

    Koljonen, K. I. I.; Russell, D. M.; Corral-Santana, J. M.; Armas Padilla, M.; Muñoz-Darias, T.; Lewis, F.; Coriat, M.; Bauer, F. E.

    2016-07-01

    We study in detail the evolution of the 2015 outburst of GS 1354-64 (BW Cir) at optical, UV and X-ray wavelengths using Faulkes Telescope South/Las Cumbres Observatory Global Telescope Network, Small & Moderate Aperture Research Telescope System and Swift. The outburst was found to stay in the hard X-ray state, albeit being anomalously luminous with a peak luminosity of LX > 0.15 LEdd, which could be the most luminous hard state observed in a black hole X-ray binary. We found that the optical/UV emission is tightly correlated with the X-ray emission, consistent with accretion disc irradiation and/or a jet producing the optical emission. The X-ray spectra can be fitted well with a Comptonization model, and show softening towards the end of the outburst. In addition, we detect a QPO in the X-ray light curves with increasing centroid frequency during the peak and decay periods of the outburst. The long-term optical light curves during quiescence show a statistically significant, slow rise of the source brightness over the 7 years prior to the 2015 outburst. This behaviour as well as the outburst evolution at all wavelengths studied can be explained by the disc instability model with irradiation and disc evaporation/condensation.

  14. A "high-hard" outburst of the black hole X-ray binary GS 1354-64

    CERN Document Server

    Koljonen, K I I; Corral-Santana, J M; Padilla, M Armas; Muñoz-Darias, T; Lewis, F; Coriat, M; Bauer, F E

    2016-01-01

    We study in detail the evolution of the 2015 outburst of GS 1354-64 (BW Cir) at optical, UV and X-ray wavelengths using Faulkes Telescope South, SMARTS and Swift. The outburst was found to stay in the hard X-ray state, albeit being anomalously luminous with a peak luminosity of L$_{X} >$ 0.15 L$_{Edd}$, which could be the most luminous hard state observed in a black hole X-ray binary. We found that the optical/UV emission is tightly correlated with the X-ray emission, consistent with accretion disc irradiation and/or a jet producing the optical emission. The X-ray spectra can be fitted well with a Comptonisation model, and show softening towards the end of the outburst. In addition, we detect a QPO in the X-ray lightcurves with increasing centroid frequency during the peak and decay periods of the outburst. The long-term optical lightcurves during quiescence show a statistically significant, slow rise of the source brightness over the 7 years prior to the 2015 outburst. This behaviour as well as the outburst ...

  15. Hard X-ray photoelectron spectroscopy of bulk and thin films of Heusler compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kozina, Xeniya

    2012-03-26

    X-ray photoemission spectroscopy (XPS) is one of the most universal and powerful tools for investigation of chemical states and electronic structures of materials. The application of hard X-rays increases the inelastic mean free path of the emitted electrons within the solid and thus makes hard X-ray photoelectron spectroscopy (HAXPES) a bulk sensitive probe for solid state research and especially a very effective nondestructive technique to study buried layers. This thesis focuses on the investigation of multilayer structures, used in magnetic tunnel junctions (MTJs), by a number of techniques applying HAXPES. MTJs are the most important components of novel nanoscale devices employed in spintronics. The investigation and deep understanding of the mechanisms responsible for the high performance of such devices and properties of employed magnetic materials that are, in turn, defined by their electronic structure becomes feasible applying HAXPES. Thus the process of B diffusion in CoFeB-based MTJs was investigated with respect to the annealing temperature and its influence on the changes in the electronic structure of CoFeB electrodes that clarify the behaviour and huge TMR ratio values obtained in such devices. These results are presented in chapter 6. The results of investigation of the changes in the valence states of buried off-stoichiometric Co{sub 2}MnSi electrodes were investigated with respect to the Mn content {alpha} and its influence on the observed TMR ratio are described in chapter 7. Magnetoelectronic properties such as exchange splitting in ferromagnetic materials as well as the macroscopic magnetic ordering can be studied by magnetic circular dichroism in photoemission (MCDAD). It is characterized by the appearance of an asymmetry in the photoemission spectra taken either from the magnetized sample with the reversal of the photon helicity or by reversal of magnetization direction of the sample when the photon helicity direction is fixed. Though

  16. Investigation of drug loading behavior of dendrimers nano-vectors with synchrotron radiation hard X-ray fluorescence analysis

    International Nuclear Information System (INIS)

    Background: Synchrotron Radiation X-ray fluorescence analysis is an advanced method of quantitative elemental analysis. It is a scientific platform for life science, material science, and environmental science. Purpose: In this present study, the drug loading behavior of dendrimers nano-vectors was investigated by using the method of Synchrotron Radiation X-ray fluorescence analysis. Methods: The copper (Ⅱ) ions were loaded into acetyl-modified generation 5(G5) PAMAM dendrimers. We monitored and imaged the distribution of copper in A549 cell by Shanghai Synchrotron Radiation Facility (SSRF) to observe the cellular uptake of copper-dendrimers conjugates. Results: The results of hard X-ray fluorescence mapping showed a stronger fluorescence of Cu in the cells treated with G5-Ac-Cu than that of control. Conclusions: This investigation provided a method of using synchrotron radiation X-ray fluorescence analysis to study the drug loading behavior of dendrimers. (authors)

  17. Fully coherent hard X-ray generation by two-stage phase-merging enhanced harmonic generation

    Science.gov (United States)

    Wang, Guang-Lei; Zhang, Wei-Qing; Yang, Xue-Ming; Feng, Chao; Deng, Hai-Xiao

    2016-09-01

    Cascading stages of seeded free electron lasers (FELs) is a promising way to produce fully coherent X-ray radiation. We study a new approach to produce coherent hard X-rays by cascading the recently proposed phase-merging enhanced harmonic generation (PEHG) The scheme consists of one dogleg and two PEHG configurations, and may be one of the leading candidates for the extracted undulator branch in future X-ray FEL facilities. FEL physics studies show that such a scheme is feasible within the present technology and can provide high brightness X-ray radiation pulses with narrow bandwidth and full coherence The radiated peak power at 1 Å wavelength converted from an initial 200 nm seed laser is over 2 GW Supported by the National Natural Science Foundation of China (21127902 & 11322550) and Ten Thousand Talent Program

  18. Fully coherent hard X-ray generation by two-stage of Phase-merging Enhanced Harmonic Generation

    CERN Document Server

    Wang, Guanglei; Yang, Xueming; Feng, Chao; Deng, Haixiao

    2016-01-01

    Cascading stages of seeded free electron laser (FEL) is a promising way to produce fully coherent X-ray radiations. We study a new approach to produce coherent hard X-rays by cascading the recently proposed phase-merging enhanced harmonic generation (PEHG). The scheme consists of one dogleg and two PEHG configurations, which may be one of the leading candidates for the extracted undulator branch in future X-ray FEL facilities. FEL physics studies show that such a scheme is feasible within the present technology and can provide high brightness X-ray radiation pulses with narrow bandwidth and fully coherence, and the radiated peak power at 1 angstrom wavelength converted from an initial 200 nm seed laser is over 2 GW.

  19. The OPTX Project II: Hard X-ray Luminosity Functions of Active Galactic Nuclei for z<5

    OpenAIRE

    Yencho, B.; Barger, A. J.; Trouille, L.; Winter, L. M.

    2009-01-01

    We use the largest, most uniform, and most spectroscopically complete to faint X-ray flux limits Chandra sample to date to construct hard 2-8 keV rest-frame X-ray luminosity functions (HXLFs) of spectroscopically identified active galactic nuclei (AGNs) to z~5. In addition, we use a new 2-8 keV local sample selected by the very hard (14-195 keV) SWIFT 9-month Burst Alert Telescope (BAT) survey to construct the local 2-8 keV HXLF. We do maximum likelihood fits of the combined distant plus loca...

  20. Utilization of synchrotron radiation in analytical chemistry. Hard X-ray emission and absorption spectroscopy

    International Nuclear Information System (INIS)

    This paper takes up X-ray absorption fine structure (XAFS) method, which has widely spread due to the energy selectivity of radiation, and fluorescent X-ray spectroscopy, which is utilized in non-destructive screening analysis and high precision quantitative analysis method for bulk materials due to the popularity of commercialized devices that usually use X-ray sources, and explains their devices, measurement principle, and applications. As the device, it introduces X-ray fluorescence spectrometer that was installed in SPring-8 beamline (BL05SS). As the application examples of fluorescent X-ray spectroscopy, it introduces the analysis of heavy elements due to high-energy X-ray excitation, and fluorescent X-ray analysis using microbeams. As the example of the use of XAFS method, it introduces the in-situ observation of the charging/discharging process of lithium battery. (A.O.)

  1. Plasma heating in solar flares and their soft and hard X-ray emissions

    International Nuclear Information System (INIS)

    symmetric and there are no differences in the emissions originating from the feet of the flares loop and by relative simplicity of the applied numerical 1D code and procedures. No doubt a significant refinement of the applied numerical models and more sophisticated implementation of the various physical mechanisms involved are required to achieve a better agreement. Despite these problems, a collation of modeled results with observations shows that soft and hard X-ray emissions observed for analyzed single-loop-like events may be fully explained by electron-beam-driven evaporation only.

  2. Hard x-ray polarimetry with a thick CdTe position sensitive spectrometer

    Science.gov (United States)

    Caroli, Ezio; Bertuccio, Giuseppe; Cola, Adriano; Curado da Silva, R. M.; Donati, Ariano; Dusi, Waldes; Landini, Gianni; Siffert, Paul; Sampietro, Marco; Stephen, John B.

    2000-12-01

    Even though it is recognized that the study of polarization from cosmic high-energy sources can give very important information about the nature of the emission mechanism, to date very few measurements have been attempted. For several years we have proposed the use of a thick CdTe array as a position sensitive spectrometer for hard X- and soft gamma-ray astronomy, a design which is also efficient for use as a polarimeter at energies above approximately 100 keV. Herein we describe the preliminary results of our study of a polarimeter based on 4096 CdTe microcrystals that we would like to develop for a high altitude balloon experiment. We present the telescope concept with a description of each subsystem together with some results on activities devoted to the optimization of the CdTe detector units' response. Furthermore we give an evaluation of the telescope performance in terms of achievable spectroscopic and polarimetric performance. In particular we will show the results of Monte Carlo simulations developed to evaluate the efficiency of our detector as a hard X ray polarimeter.

  3. The Low-High-Low Trend of Type III Radio Burst Starting Frequencies and Solar Flare Hard X-rays

    CERN Document Server

    Reid, Hamish A S; Kontar, Eduard P

    2014-01-01

    Using simultaneous X-ray and radio observations from solar flares, we investigate the link between the type III radio burst starting frequency and hard X-ray spectral index. For a proportion of events the relation derived between the starting height (frequency) of type III radio bursts and the electron beam velocity spectral index (deduced from X-rays) is used to infer the spatial properties (height and size) of the electron beam acceleration region. Both quantities can be related to the distance travelled before an electron beam becomes unstable to Langmuir waves. To obtain a list of suitable events we considered the RHESSI catalogue of X-ray flares and the Phoenix 2 catalogue of type III radio bursts. From the 200 events that showed both type III and X-ray signatures, we selected 30 events which had simultaneous emission in both wavelengths, good signal to noise in the X-ray domain and > 20 seconds duration. We find that > 50 % of the selected events show a good correlation between the starting frequencies ...

  4. SUPERMODEL ANALYSIS OF THE HARD X-RAY EXCESS IN THE COMA CLUSTER

    International Nuclear Information System (INIS)

    The Supermodel (SM) provides an accurate description of the thermal contribution by the hot intracluster plasma which is crucial for the analysis of the hard excess. In this paper, the thermal emissivity in the Coma cluster is derived starting from the intracluster gas temperature and density profiles obtained by the SM analysis of X-ray observables: the XMM-Newton temperature profile and the ROSAT brightness distribution. The SM analysis of the BeppoSAX/Phoswich Detector System (PDS) hard X-ray (HXR) spectrum confirms our previous results, namely, an excess at the confidence level (c.l.) of ∼4.8σ and a nonthermal (NT) flux of (1.30 ± 0.40) x 10-11 erg cm-2 erg cm-1 in the energy range 20-80 keV. A recent joint XMM-Newton/Suzaku analysis reports an upper limit of ∼6 x 10-12 erg cm-2 erg cm-1 in the energy range 20-80 keV for the NT flux with an average gas temperature of 8.45 ± 0.06 keV and an excess of NT radiation at a c.l. above 4σ, without including systematic effects, for an average XMM-Newton temperature of 8.2 keV in the Suzaku/HXD-PIN FOV, in agreement with our earlier PDS analysis. Here we present a further evidence of the compatibility between the Suzaku and BeppoSAX spectra, obtained by our SM analysis of the PDS data, when the smaller size of the HXD-PIN FOV and the two different average temperatures derived by XMM-Newton and by the joint XMM-Newton/Suzaku analysis are taken into account. The consistency of the PDS and HXD-PIN spectra reaffirms the presence of an NT component in the HXR spectrum of the Coma cluster. The SM analysis of the PDS data reports an excess at c.l. above 4σ also for the higher average temperature of 8.45 keV thanks to the PDS FOV being considerably greater than the HXD-PIN FOV.

  5. Analysis of Intermittency in Submillimeter Radio and Hard X-Ray Data During the Impulsive Phase of a Solar Flare

    Science.gov (United States)

    Giménez de Castro, G.; Simões, P. J. A.; Raulin, J.-P.; Guimarães, O. M.

    2016-08-01

    We present an analysis of intermittent processes occurring during the impulsive phase of the flare SOL2012-03-13, using hard X-rays and submillimeter radio data. Intermittency is a key characteristic in turbulent plasmas and has so far only been analyzed for hard X-ray data. Since in a typical flare the same accelerated electron population is believed to produce both hard X-rays and gyrosynchrotron radiation, we compare the two time profiles by searching for intermittency signatures. For this, we define a cross-wavelet power spectrum, which is used to obtain the local intermittency measure, or {LIM}. When greater than three, the square {LIM} coefficients indicate a local intermittent process. The {LIM}2 coefficient distribution in time and scale helps to identify avalanche or cascade energy release processes. We find two different and well-separated intermittent behaviors in the submillimeter data: for scales greater than 20 s, a broad distribution during the rising and maximum phases of the emission seems to favor a cascade process; for scales below 1 s, short pulses centered on the peak time are representative of avalanches. When applying the same analysis to hard X-rays, we find that only the scales above 10 s produce a distribution related to a cascade energy fragmentation. Our results suggest that different acceleration mechanisms are responsible for tens of keV and MeV energy ranges of electrons.

  6. Simultaneous soft and hard X-ray spectroscopy of AM Herculis with EXOSAT: Discovery of photospheric absorption features

    Science.gov (United States)

    Paerels, Frits; Heise, John; Teeseling, Andre Van

    1994-01-01

    We present 0.1-10 keV spectroscopic observations of AM Herculis obtained with the Transmission Grating Spectrometers and Medium Energy experiments on EXOSAT, taken when the object was in its 'reversed X-ray mode.' The observation covers over six binary orbits without interruption, enabling us to analyze the phase and intensity dependence of both the hard and the soft spectrum simultaneously. We resolve the optically thick soft X-ray spectrum, and find definite evidence for time- and phase-dependent photospheric absorption structure arising in the white dwarf atmosphere. We present a simple empirical analysis of the combined soft and hard X-ray spectra, to examine whether the effect of a better determination of the column density of neutral absorbing material, afforded by our data, would solve the problem of the large relative soft X-ray overluminosity previously observed in AM Her. We find that a single absorbing column fits the entire spectrum, and that the column densities implied are indeed substantially lower than previously estimated. However, during half the binary orbit we still determine a strong lower limit to the soft-to-hard luminosity ratio of L(sub soft)/L(sub hard) is greater than or approximately equal to 10, in conflict with the simple radiative shock models for the accretion region. We argue that this indicates the need to reexamine the luminosity problem using explicit models for the emission spectrum based on a full solution of the atmospheric radiative transfer problem.

  7. The First Focused Hard X-Ray Images of the Sun With NuSTAR

    DEFF Research Database (Denmark)

    Grefenstette, Brian W.; Glesener, Lindsay; Krucker, Sam;

    2016-01-01

    We present results from the the first campaign of dedicated solar observations undertaken by the Nuclear Spectroscopic Telescope ARray (NuSTAR) hard X-ray (HXR) telescope. Designed as an astrophysics mission, NuSTAR nonetheless has the capability of directly imaging the Sun at HXR energies (>3 ke...

  8. In-flight PSF calibration of the NuSTAR hard X-ray optics

    DEFF Research Database (Denmark)

    An, Hongjun; Madsen, Kristin K.; Westergaard, Niels J.;

    2014-01-01

    We present results of the point spread function (PSF) calibration of the hard X-ray optics of the Nuclear Spectroscopic Telescope Array (NuSTAR). Immediately post-launch, NuSTAR has observed bright point sources such as Cyg X-1, Vela X-1, and Her X-1 for the PSF calibration. We use the point sour...

  9. GRAPE - A Balloon-Borne Gamma-Ray Polarimeter Experiment

    CERN Document Server

    Bloser, P F; Macri, J R; McConnell, M L; Narita, T; Ryan, J M

    2005-01-01

    This paper reviews the development status of GRAPE (the Gamma-Ray Polarimeter Experiment), a hard X-ray Compton Polarimeter. The purpose of GRAPE is to measure the polarization of hard X-rays in the 50-300 keV energy range. We are particularly interested in X-rays that are emitted from solar flares and gamma-ray bursts (GRBs), although GRAPE could also be employed in the study of other astrophysical sources. Accurately measuring the polarization of the emitted radiation will lead to a better understating of both emission mechanisms and source geometries. The GRAPE design consists of an array of plastic scintillators surrounding a central high-Z crystal scintillator. The azimuthal distribution of photon scatters from the plastic array into the central calorimeter provides a measure of the polarization fraction and polarization angle of the incident radiation. The design of the detector provides sensitivity over a large field-of-view (>pi steradian). The design facilitates the fabrication of large area arrays w...

  10. Solar Impulsive Hard X-Ray Emission and Two-Stage Electron Acceleration

    Institute of Scientific and Technical Information of China (English)

    Tian-Xi Zhang; Arjun Tan; Shi Tsan Wu

    2006-01-01

    Heating and acceleration of electrons in solar impulsive hard X-ray (HXR) flares are studied according to the two-stage acceleration model developed by Zhang for solar 3Herich events. It is shown that electrostatic H-cyclotron waves can be excited at a parallel phase velocity less than about the electron thermal velocity and thus can significantly heat the electrons (up to 40 MK) through Landau resonance. The preheated electrons with velocities above a threshold are further accelerated to high energies in the flare-acceleration process. The flareproduced electron spectrum is obtained and shown to be thermal at low energies and power law at high energies. In the non-thermal energy range, the spectrum can be double power law if the spectral power index is energy dependent or related. The electron energy spectrum obtained by this study agrees quantitatively with the result derived from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) HXR observations in the flare of 2002 July 23. The total flux and energy flux of electrons accelerated in the solar flare also agree with the measurements.

  11. Hard x-ray/soft gamma-ray telescope designs for future astrophysics missions

    Science.gov (United States)

    Della Monica Ferreira, Desiree; Christensen, Finn E.; Pivovaroff, Michael J.; Brejnholt, Nicolai; Fernandez-Perea, Monica; Westergaard, Niels Jørgen S.; Jakobsen, Anders C.; Descalle, Marie-Anne; Soufli, Regina; Vogel, Julia K.

    2013-09-01

    We present several concept designs of hard X-ray/soft λ-ray focusing telescopes for future astrophysics missions. The designs are based on depth graded multilayer coatings. These have been successfully employed on the NuSTAR mission for energies up to 80 keV. Recent advances in demonstrating theoretical reflectivities for candidate multilayer material combinations up to 400 keV including effects of incoherent scatter has given an experimental base for extending this type of designs to the soft λ-ray range. At the same time, the calibration of the in-flight performance of the NuSTAR mission has given a solid understanding and modelling of the relevant effects influencing the performance, including optical constants, roughness, scatter, non-uniformities and figure error. This allows for a realistic extension for designs going to much higher energies. Similarly, both thin slumped glass and silicon pore optics has been developed to a prototype stage which promises imaging resolution in the sub 10 arcsecond range. We present designs based on a 20 m and 50 m focal lengths with energy ranges up to 200 keV and 600 keV.

  12. Magnetic dichroism in angle-resolved hard x-ray photoemission from buried layers

    Science.gov (United States)

    Kozina, Xeniya; Fecher, Gerhard H.; Stryganyuk, Gregory; Ouardi, Siham; Balke, Benjamin; Felser, Claudia; Schönhense, Gerd; Ikenaga, Eiji; Sugiyama, Takeharu; Kawamura, Naomi; Suzuki, Motohiro; Taira, Tomoyuki; Uemura, Tetsuya; Yamamoto, Masafumi; Sukegawa, Hiroaki; Wang, Wenhong; Inomata, Koichiro; Kobayashi, Keisuke

    2011-08-01

    This work reports the measurement of magnetic dichroism in angular-resolved photoemission from in-plane magnetized buried thin films. The high bulk sensitivity of hard x-ray photoelectron spectroscopy (HAXPES) in combination with circularly polarized radiation enables the investigation of the magnetic properties of buried layers. HAXPES experiments with an excitation energy of 8 keV were performed on exchange-biased magnetic layers covered by thin oxide films. Two types of structures were investigated with the IrMn exchange-biasing layer either above or below the ferromagnetic layer: one with a CoFe layer on top and another with a Co2FeAl layer buried beneath the IrMn layer. A pronounced magnetic dichroism is found in the Co and Fe 2p states of both materials. The localization of the magnetic moments at the Fe site conditioning the peculiar characteristics of the Co2FeAl Heusler compound, predicted to be a half-metallic ferromagnet, is revealed from the magnetic dichroism detected in the Fe 2p states.

  13. Spatio-temporal dynamics of sources of hard X-ray pulsations in solar flares

    CERN Document Server

    Kuznetsov, S A; Morgachev, A S; Struminsky, A B

    2016-01-01

    We present systematic analysis of spatio-temporal evolution of sources of hard X-ray (HXR) pulsations in solar flares. We concentrate on disk flares whose impulsive phase are accompanied by a series of more than three peaks (pulsations) of HXR emission detected in the RHESSI 50-100 keV channel with 4-second cadence. 29 such flares observed from February 2002 to June 2015 with time differences between successive peaks of 8-270 s are studied. The main observational result is that sources of HXR pulsations in all flares are not stationary, they demonstrate apparent displacements from pulsation to pulsation. The flares can be subdivided into two groups depending on character of dynamics of HXR sources. The group-1 consists of 16 flares (55%) with systematic dynamics of HXR sources from pulsation to pulsation with respect to a magnetic polarity inversion line (MPIL), which has simple extended trace on the photosphere. The group-2 consists of 13 flares (45%) with more chaotic displacements of HXR sources with respe...

  14. Prospects for CW and LP operation of the European XFEL in hard X-ray regime

    Energy Technology Data Exchange (ETDEWEB)

    Brinkmann, R.; Schneidmiller, E.A.; Sekutowicz, J.; Yurkov, M.V.

    2014-03-15

    The European XFEL will operate nominally at 17.5 GeV in SP (short pulse) mode with 0.65 ms long bunch train and 10 Hz repetition rate. A possible upgrade of the linac to CW (continuous wave) or LP (long pulse) modes with a corresponding reduction of electron beam energy is under discussion since many years. Recent successes in the dedicated R and D program allow to forecast a technical feasibility of such an upgrade in the foreseeable future. One of the challenges is to provide sub-Aangstrom FEL operation in CW and LP modes. In this paper we perform a preliminary analysis of a possible operation of the European XFEL in the hard X-ray regime in CW and LP modes with the energies of 7 GeV and 10 GeV, respectively. We consider lasing in the baseline XFEL undulator as well as in a new undulator with a reduced period. We show that, with reasonable requirements on electron beam quality, lasing on the fundamental will be possible in sub-Aangstrom regime. As an option for generation of brilliant photon beams at short wavelengths we also consider harmonic lasing that has recently attracted a significant attention.

  15. Hard X-ray Emission During Flares and Photospheric Field Changes

    CERN Document Server

    Burtseva, O; Petrie, G J D; Pevtsov, A A

    2015-01-01

    We study the correlation between abrupt permanent changes of magnetic field during X-class flares observed by the GONG and HMI instruments, and the hard X-ray (HXR) emission observed by RHESSI, to relate the photospheric field changes to the coronal restructuring and investigate the origin of the field changes. We find that spatially the early RHESSI emission corresponds well to locations of the strong field changes. The field changes occur predominantly in the regions of strong magnetic field near the polarity inversion line (PIL). The later RHESSI emission does not correspond to significant field changes as the flare footpoints are moving away from the PIL. Most of the field changes start before or around the start time of the detectable HXR signal, and they end at about the same time or later than the detectable HXR flare emission. Some of the field changes propagate with speed close to that of the HXR footpoint at a later phase of the flare. The propagation of the field changes often takes place after the...

  16. Hard X-Ray sources observed by INTEGRAL/IBIS and their science

    CERN Document Server

    Ubertini, Pietro

    2008-01-01

    After more than 5.5 years of in flight lifetime, the ESA space observatory INTEGRAL is depicting a new scenario in the soft gamma Ray domain. With the observation and discovery of more than 400 hard X-Ray sources has changed our view of a moderately crowded and dark sky basically populated by "peculiar" and erratic sources. The new high energy sky is also composed by a large variety of "normal" though very powerful objects, characterized by new accretion and acceleration processes. Among the 421 sources detected in the energy range 17-100 keV the 3rd INTEGRAL/IBIS catalogue includes 41% galactic accreting system, 29% extragalactic objects, 8% of other types, and 26% not classified i.e. of unknown origin. If compared to to previous IBIS/ISGRI surveys it is clear that there is a continuous increase of the rate of discovery of HMXB, an increase in the number of AGN discovered, including a variety of distant QSOs, basically due to the increased exposure away from the Galaxy Plane, while the percentage of sources ...

  17. Distributed seeding for narrow-line width hard x-ray free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Anisimov, Petr Mikhaylovich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewellen, IV, John W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Marksteiner, Quinn R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-09

    We describe a new FEL line-narrowing technique called distributed seeding (DS), using Si(111) Bragg crystal monochromators to enhance the spectral brightness of the MaRIE hard X-ray freeelectron laser. DS differs from self-seeding in three important aspects. First, DS relies on spectral filtering of the radiation at multiple locations along the undulator, with a monochromator located every few power gain lengths. Second, DS performs filtering early in the exponential gain region before SASE spikes start to appear in the radiation longitudinal profile. Third, DS provides the option to select a wavelength longer than the peak of the SASE gain curve, which leads to improved spectral contrast of the seeded FEL over the SASE background. Timedependent Genesis simulations show the power-vs-z growth curves for DS exhibit behaviors of a seeded FEL amplifier, such as exponential growth region immediately after the filters. Of the seeding approaches considered, the two-stage DS spectra produce the highest contrast of seeded FEL over the SASE background and that the three-stage DS provides the narrowest linewidth with a relative spectral FWHM of 8 X 10-5 .

  18. In operando tracking phase transformation evolution of lithium iron phosphate with hard X-ray microscopy

    Science.gov (United States)

    Wang, Jiajun; Chen-Wiegart, Yu-Chen Karen; Wang, Jun

    2014-08-01

    The delithiation reaction in lithium ion batteries is often accompanied by an electrochemically driven phase transformation process. Tracking the phase transformation process at nanoscale resolution during battery operation provides invaluable information for tailoring the kinetic barrier to optimize the physical and electrochemical properties of battery materials. Here, using hard X-ray microscopy—which offers nanoscale resolution and deep penetration of the material, and takes advantage of the elemental and chemical sensitivity—we develop an in operando approach to track the dynamic phase transformation process in olivine-type lithium iron phosphate at two size scales: a multiple-particle scale to reveal a rate-dependent intercalation pathway through the entire electrode and a single-particle scale to disclose the intraparticle two-phase coexistence mechanism. These findings uncover the underlying two-phase mechanism on the intraparticle scale and the inhomogeneous charge distribution on the multiple-particle scale. This in operando approach opens up unique opportunities for advancing high-performance energy materials.

  19. In operando tracking phase transformation evolution of lithium iron phosphate with hard X-ray microscopy.

    Science.gov (United States)

    Wang, Jiajun; Chen-Wiegart, Yu-chen Karen; Wang, Jun

    2014-01-01

    The delithiation reaction in lithium ion batteries is often accompanied by an electrochemically driven phase transformation process. Tracking the phase transformation process at nanoscale resolution during battery operation provides invaluable information for tailoring the kinetic barrier to optimize the physical and electrochemical properties of battery materials. Here, using hard X-ray microscopy--which offers nanoscale resolution and deep penetration of the material, and takes advantage of the elemental and chemical sensitivity--we develop an in operando approach to track the dynamic phase transformation process in olivine-type lithium iron phosphate at two size scales: a multiple-particle scale to reveal a rate-dependent intercalation pathway through the entire electrode and a single-particle scale to disclose the intraparticle two-phase coexistence mechanism. These findings uncover the underlying two-phase mechanism on the intraparticle scale and the inhomogeneous charge distribution on the multiple-particle scale. This in operando approach opens up unique opportunities for advancing high-performance energy materials. PMID:25087693

  20. Simulation of Quiet-Sun Hard X-rays Related to Solar Wind Superhalo Electrons

    CERN Document Server

    Wang, Wen; Krucker, Sam; Hannah, Iain

    2016-01-01

    In this paper, we propose that the accelerated electrons in the quiet Sun could collide with the solar atmosphere to emit Hard X-rays (HXRs) via non-thermal bremsstrahlung, while some of these electrons would move upwards and escape into the interplanetary medium, to form a superhalo electron population measured in the solar wind. After considering the electron energy loss due to Coulomb collisions and the ambipolar electrostatic potential, we find that the sources of the superhalo could only occur high in the corona (at a heliocentric altitude $\\gtrsim 1.9$ R$_\\odot$ (the mean radius of the Sun)), to remain a power-law shape of electron spectrum as observed by STEREO at 1AU near solar minimum (Wang et al., 2012). The modeled quiet-Sun HXRs related to the superhalo electrons fit well to a power-law spectrum, $f \\sim \\varepsilon^{-\\gamma}$, with an index $\\gamma$ $\\approx$ 2.0 - 2.3 (3.3 - 3.7) at 10 - 100 keV, for the warm/cold thick-target (thin-target) emissions produced by the downward-traveling (upward-tr...

  1. A hard X-ray telescope/concentrator design based on graded period multilayer coatings

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Joensen, K. D.; Gorenstein, P.;

    1995-01-01

    It is shown that compact designs of multifocus, conical approximations to highly nested Wolter I telescopes, as well as single reflection concentrators, employing realistic graded period W/Si or Ni/C multilayer coatings, allow one to obtain more than 1000 cm2 of on-axis effective area at 40 keV a....../cm2/s/keV which demonstrates the great potential of this hard X-ray imaging telescope in the energy range up to 100 keV....... of the telescope configuration provided that mirrors can be coated to an inner radius of 3 cm. Specifically we find that a change of focal length from 5 to 12 m affects the effective area by less than 10%. In addition the result is insensitive to the thickness of the individual mirror shell provided...... that it is smaller than roughly 1 mm. The design can be realized with foils as thin (≤0.4 mm) as used for ASCA and SODART or with closed, slightly thicker (∼1.0 mm) mirror shells as used for JET-X and XMM. The effect of an increase of the inner radius is quantified on the effective area for multilayered mirrors up...

  2. Hard X-ray polarimetry with Caliste, a high performance CdTe based imaging spectrometer

    CERN Document Server

    Antier, S; Limousin, O; Caroli, E; da Silva, R M Curado; Blondel, C; Chipaux, R; Honkimaki, V; Horeau, B; Laurent, P; Maia, J M; Meuris, A; Del Sordo, S; Stephen, J B

    2015-01-01

    Since the initial exploration of soft gamma-ray sky in the 60's, high-energy celestial sources have been mainly characterized through imaging, spectroscopy and timing analysis. Despite tremendous progress in the field, the radiation mechanisms at work in sources such as neutrons stars and black holes are still unclear. The polarization state of the radiation is an observational parameter which brings key additional information about the physical process. This is why most of the projects for the next generation of space missions covering the tens of keV to the MeV region require a polarization measurement capability. A key element enabling this capability is a detector system allowing the identification and characterization of Compton interactions as they are the main process at play. The hard X-ray imaging spectrometer module, developed in CEA with the generic name of Caliste module, is such a detector. In this paper, we present experimental results for two types of Caliste-256 modules, one based on a CdTe cr...

  3. The First Focused Hard X-ray Images of the Sun with NuSTAR

    Science.gov (United States)

    Grefenstette, Brian W.; Glesener, Lindsay; Krucker, Säm; Hudson, Hugh; Hannah, Iain G.; Smith, David M.; Vogel, Julia K.; White, Stephen M.; Madsen, Kristin K.; Marsh, Andrew J.; Caspi, Amir; Chen, Bin; Shih, Albert; Kuhar, Matej; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Forster, Karl; Hailey, Charles J.; Harrison, Fiona A.; Miyasaka, Hiromasa; Stern, Daniel; Zhang, William W.

    2016-07-01

    We present results from the the first campaign of dedicated solar observations undertaken by the Nuclear Spectroscopic Telescope ARray (NuSTAR) hard X-ray (HXR) telescope. Designed as an astrophysics mission, NuSTAR nonetheless has the capability of directly imaging the Sun at HXR energies (>3 keV) with an increase in sensitivity of at least two magnitude compared to current non-focusing telescopes. In this paper we describe the scientific areas where NuSTAR will make major improvements on existing solar measurements. We report on the techniques used to observe the Sun with NuSTAR, their limitations and complications, and the procedures developed to optimize solar data quality derived from our experience with the initial solar observations. These first observations are briefly described, including the measurement of the Fe K-shell lines in a decaying X-class flare, HXR emission from high in the solar corona, and full-disk HXR images of the Sun.

  4. Optimization of reconstructed quality of hard x-ray phase microtomography.

    Science.gov (United States)

    Liu, Huiqiang; Wu, Xizeng; Xiao, Tiqiao

    2015-06-20

    For applications of hard x-ray propagation-based phase-contrast computed microtomography (PPCT) in high-resolution biological research, high spatial resolution and high contrast-to-noise ratio are simultaneously required for tiny structural discrimination and characterization. Most existing micro-CT techniques to improve image quality are limited by high cost, physical limitations, and complexity of the experimental hardware and setup. In this work, a novel PPCT technique, which combines a wavelet-transform-based modulation transform function compensation algorithm and a generalized phase-retrieval algorithm, is proposed to optimize the reconstruction quality of tomographic slices. Our experimental results, which compared the spatial resolutions and contrast-to-noise ratios of reconstructed images, demonstrated the validity of the proposed generalized PPCT technique. The experimental results showed that the proposed generalized PPCT technique is superior to the direct PPCT and the linearized phase-retrieval PPCT techniques. This novel PPCT technique demonstrates great potential for biological imaging, especially for applications that require high spatial resolution and limit radiation exposure. PMID:26193002

  5. Quantitative hard x-ray phase contrast imaging of micropipes in SiC

    International Nuclear Information System (INIS)

    Peculiarities of quantitative hard x-ray phase contrast imaging of micropipes in SiC are discussed. The micropipe is assumed as a hollow cylinder with an elliptical cross section. The major and minor diameters can be restored using the least square fitting procedure by comparing the experimental data, i.e. the profile across the micropipe axis, with those calculated based on phase contrast theory. It is shown that one projection image gives an information which does not allow a complete determination of the elliptical cross section, if an orientation of micropipe is not known. Another problem is a weak accuracy in estimating the diameters, partly because of using pink synchrotron radiation, which is necessary because a monochromatic beam intensity is not sufficient to reveal the weak contrast from a very small object. The general problems of accuracy in estimating the two diameters using the least square procedure are discussed. Two experimental examples are considered to demonstrate small as well as modest accuracies in estimating the diameters

  6. Fabrication of laser deposited high-quality multilayer zone plates for hard X-ray nanofocusing

    Energy Technology Data Exchange (ETDEWEB)

    Eberl, Christian; Döring, Florian; Liese, Tobias; Schlenkrich, Felix; Roos, Burkhard; Hahn, Matthias [Institut für Materialphysik, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Hoinkes, Thomas; Rauschenbeutel, Arno [Vienna Center for Quantum Science and Technology, TU Wien – Atominstitut, Stadionallee 2, 1020 Wien (Austria); Osterhoff, Markus; Salditt, Tim [Institut für Röntgenphysik, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Krebs, Hans-Ulrich, E-mail: krebs@ump.gwdg.de [Institut für Materialphysik, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany)

    2014-07-01

    Recently, we demonstrated unprecedented sub-5 nm point focusing of hard X-rays (at 7.9 keV) based on the combination of a high gain Kirkpatrick–Baez (KB) mirror system and a high resolution W/Si multilayer zone plate (MZP). This MZP was prepared by the combination of pulsed laser deposition (PLD) and focused ion beam (FIB). Despite the small focus size, the MZP's quality suffered from sufficient but comparatively low efficiency (2%). In this paper we discuss how to overcome limitations of MZP fabrication by PLD by investigating the material systems W/Si, W/ZrO{sub 2}, and Ta{sub 2}O{sub 5}/ZrO{sub 2}. We give a detailed description on the optimization processes for the deposition of smooth multilayers with highly precise layer thicknesses on a rotating wire. Furthermore, we present our latest results regarding a Ta{sub 2}O{sub 5}/ZrO{sub 2} MZP, which has been proven already to be a system of high potential in the very first experiments as the efficiency reached 6.9% (at 18 keV).

  7. Monitoring the hard X-ray sky with SuperAGILE

    CERN Document Server

    Feroci, M; Del Monte, E; Donnarumma, I; Evangelista, Y; Lapshov, I; Lazzarotto, F; Pacciani, L; Rapisarda, M; Soffitta, P; Di Persio, G; Frutti, M; Mastropietro, M; Morelli, E; Porrovecchio, G; Rubini, A; Antonelli, A; Argan, A; Barbiellini, G; Boffelli, F; Bulgarelli, A; Caraveo, P; Cattaneo, P W; Chen, A W; Cocco, V; Colafrancesco, S; Cutini, S; D'Ammando, F; De Paris, G; Di Cocco, G; Fanari, G; Ferrari, A; Fiorini, M; Fornari, F; Fuschino, F; Froysland, T; Galli, M; Gasparrini, D; Gianotti, F; Giommi, P; Giuliani, A; Labanti, C; Liello, F; Lipari, P; Longo, F; Mattaini, E; Marisaldi, M; Mauri, A; Mauri, F; Mereghetti, S; Moretti, E; Morselli, A; Pellizzoni, A; Perotti, F; Piano, G; Picozza, P; Pilia, M; Pittori, C; Pontoni, C; Preger, B; Prest, M; Primavera, R; Pucella, G; Rappoldi, A; Rossi, E; Sabatini, S; Santolamazza, P; Tavani, M; Stellato, S; Tamburelli, F; Traci, A; Trifoglio, M; Trois, A; Vallazza, E; Vercellone, S; Verrecchia, F; Vittorini, V; Zambra, A; Zanello, D; Salotti, L

    2009-01-01

    SuperAGILE is the hard X-ray monitor of the AGILE gamma ray mission, in orbit since 23$^{rd}$ April 2007. It is an imaging experiment based on a set of four independent silicon strip detectors, equipped with one-dimensional coded masks, operating in the nominal energy range 18-60 keV. The main goal of SuperAGILE is the observation of cosmic sources simultaneously with the main gamma-ray AGILE experiment, the Gamma Ray Imaging Detector (GRID). Given its $\\sim$steradian-wide field of view and its $\\sim$15 mCrab day-sensitivity, SuperAGILE is also well suited for the long-term monitoring of Galactic compact objects and the detection of bright transients. The SuperAGILE detector properties and design allow for a 6 arcmin angular resolution in each of the two independent orthogonal projections of the celestial coordinates. Photon by photon data are continuously available by the experiment telemetry, and are used to derive images and fluxes of individual sources, with integration times depending on the source inten...

  8. Hard X-ray emission and $^{44}$Ti line features of Tycho Supernova Remnant

    CERN Document Server

    Wang, Wei

    2014-01-01

    A deep hard X-ray survey of the INTEGRAL satellite first detected the non-thermal emission up to 90 keV in the Tycho supernova (SN) remnant. Its 3 -- 100 keV spectrum is fitted with a thermal bremsstrahlung of $kT\\sim 0.81\\pm 0.45$ keV plus a power-law model of $\\Gamma \\sim 3.01\\pm 0.16$. Based on the diffusive shock acceleration theory, this non-thermal emission, together with radio measurements, implies that Tycho remnant may not accelerate protons up to $>$PeV but hundreds TeV. Only heavier nuclei may be accelerated to the cosmic ray spectral "knee". In addition, we search for soft gamma-ray lines at 67.9 and 78.4 keV coming from the decay of radioactive $^{44}$Ti in Tycho remnant by INTEGRAL. A bump feature in the 60-90 keV energy band, potentially associated with the $^{44}$Ti line emission, is found with a marginal significance level of $\\sim$ 2.6 $\\sigma$. The corresponding 3 $\\sigma$ upper limit on the $^{44}$Ti line flux amounts to 1.5 $\\times$ 10$^{-5}$ ph cm$^{-2}$ s$^{-1}$. Implications on the pro...

  9. On the Spatial Distribution of Hard X-Rays from Solar Flare Loops

    CERN Document Server

    Petrosyan, V; Petrosian, Vahe; Donaghy, Timothy Q.

    1999-01-01

    The aim of this paper is to investigate the spatial structure of the impulsive phase hard X-ray emission from solar flares. This work is motivated by the YOHKOH and the forthcoming HESSI observations. Summarizing past results, it is shown that the transport effects can account for the observations by inhomogeneous loops where there is a strong field convergence and/or density enhancement at the top of the flaring loop. Scattering by plasma turbulence at the acceleration site or pancake type pitch angle distribution of the accelerated electrons can also give rise to enhanced emission at the loop tops. These could be a natural consequence of acceleration by plasma waves. This paper considers a general case of stochastic scattering and acceleration that leads to an isotropic pitch angle distribution and an enhanced emission from the loop tops or the acceleration site. Following the formalism developed in earlier papers the strength and the spectrum of the radiation expected from the acceleration site and the foo...

  10. Design of a transmission grating hard X-ray spectrometer for laser-driven undulator sources

    Energy Technology Data Exchange (ETDEWEB)

    Werle, Christian; Maier, Andreas; Zeitler, Benno; Delbos, Niels; Gruener, Florian [University of Hamburg - CFEL, Hamburg (Germany); Kajumba, Nathaniel [Ludwig Maximilian Univ., Muenchen (Germany)

    2013-07-01

    State-of-the-art laser-driven undulator sources are already becoming very versatile and powerful light sources, especially due to their wavelength tunability and ultra-short pulses. However, being still in development, they suffer from instabilities, which can make the spectral characterization of their radiation rather challenging, especially in the few-nm range. The hard X-ray transmission grating spectrometer, presented in this talk, was specifically optimized to tackle these difficulties. Its simple base design and its fully motorized optical components grant a high degree of flexibility during operation, fitting nicely to the nature of this radiation source. During calibration the device has been proven to measure wavelengths from 18 nm to 5 nm, but was in general also designed to address the sub-nm range. Following these test runs, the spectrometer was installed during a undulator campaign and was successfully used to measure laser-driven undulator radiation from 100 eV up to 300 eV, being the highest energy photons ever demonstrated with such a source.

  11. Simbol-X Hard X-ray Focusing Mirrors: Results Obtained During the Phase A Study

    CERN Document Server

    Tagliaferri, G; Borghi, G; Burkert, W; Citterio, O; Civitani, M; Conconi, P; Cotroneo, V; Freyberg, M; Garoli, D; Gorenstein, P; Hartner, G; Mattarello, V; Orlandi, A; Pareschi, G; Romaine, S; Spiga, D; Valsecchi, G; Vernani, D

    2009-01-01

    Simbol-X will push grazing incidence imaging up to 80 keV, providing a strong improvement both in sensitivity and angular resolution compared to all instruments that have operated so far above 10 keV. The superb hard X-ray imaging capability will be guaranteed by a mirror module of 100 electroformed Nickel shells with a multilayer reflecting coating. Here we will describe the technogical development and solutions adopted for the fabrication of the mirror module, that must guarantee an Half Energy Width (HEW) better than 20 arcsec from 0.5 up to 30 keV and a goal of 40 arcsec at 60 keV. During the phase A, terminated at the end of 2008, we have developed three engineering models with two, two and three shells, respectively. The most critical aspects in the development of the Simbol-X mirrors are i) the production of the 100 mandrels with very good surface quality within the timeline of the mission; ii) the replication of shells that must be very thin (a factor of 2 thinner than those of XMM-Newton) and still h...

  12. Hard X-Ray Polarization from Non-vertical Solar Flare Loops

    Science.gov (United States)

    Emslie, A. Gordon; Bradsher, Henry L.; McConnell, Mark L.

    2008-02-01

    McConnell et al. have reported preliminary results of hard X-ray polarization measured by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) in an intense solar flare on 2002 July 23. The magnitude of the reported polarization is broadly consistent with the predictions of existing solar flare models which invoke the precipitation of a nonthermal electron beam into a dense chromospheric target. However, the orientation of the polarization vector lies at a substantial angle to the local solar radial direction. This is inconsistent with model predictions of a polarization vector along the local radial direction, a prediction that is a direct consequence of the assumption of a vertical guiding magnetic field. Smith et al., in a study of the same 2002 July 23 event, have suggested that the magnetic structure in which the flare occurs is tilted relative to the local vertical. Motivated by this observation, and by the preliminary nonradial polarization vector reported by McConnell et al., we explore the effect of tilt of the flaring loop on the magnitude and orientation of the predicted polarization vector. We find that allowing loops tilted from the local solar vertical does indeed permit a much wider range of polarization vector orientations than allowed by purely vertical loop geometries. In particular, adding tilt of the magnitude inferred by Smith et al. for the 2002 July 23 event can in principle account for both the magnitude and direction of the polarization vector reported by McConnell et al. for that event.

  13. Hard X-ray emissions from Cassiopeia A observed by INTEGRAL

    CERN Document Server

    Wang, Wei

    2016-01-01

    Cassiopeia A (Cas A) as the nearby young remnant of a core-collapse supernova is the best candidate for astrophysical studies in supernova explosion and its environment. We studied hard X-ray emissions from Cas A using the ten-year data of INTEGRAL observations, and first detected non-thermal continuum emission from the source up to 220 keV. The $^{44}$Ti line emissions at 68 and 78 keV are confirmed by our observations with a mean flux of $\\sim (2.2\\pm 0.4)\\times 10^{-5}$ ph cm$^{-2}$ s$^{-1}$, corresponding to a $^{44}$Ti yield in Cas A of $(1.3\\pm 0.4)\\times 10^{-4}$ \\ms. The continuum emission from 3 -- 500 keV can be fitted with a thermal bremsstrahlung of $kT\\sim 0.79\\pm 0.08$ keV plus a power-law model of $\\Gamma \\sim 3.13\\pm 0.03$. The non-thermal emission from Cas A is well fitted with a power-law model without a cutoff up to 220 keV. This radiation characteristic is inconsistent with the diffusive shock acceleration models with the remnant shock velocity of only 5000km s$^{-1}$. The central compact ...

  14. Solar flare hard X-ray spikes observed by RHESSI: a statistical study

    CERN Document Server

    Cheng, J X; Ding, M D; Wang, H

    2012-01-01

    Context. Hard X-ray (HXR) spikes refer to fine time structures on timescales of seconds to milliseconds in high-energy HXR emission profiles during solar flare eruptions. Aims. We present a preliminary statistical investigation of temporal and spectral properties of HXR spikes. Methods. Using a three-sigma spike selection rule, we detected 184 spikes in 94 out of 322 flares with significant counts at given photon energies, which were detected from demodulated HXR light curves obtained by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). About one fifth of these spikes are also detected at photon energies higher than 100 keV. Results. The statistical properties of the spikes are as follows. (1) HXR spikes are produced in both impulsive flares and long-duration flares with nearly the same occurrence rates. Ninety percent of the spikes occur during the rise phase of the flares, and about 70% occur around the peak times of the flares. (2) The time durations of the spikes vary from 0.2 to 2 s, wit...

  15. Multi-modal hard x-ray imaging with a laboratory source using selective reflection from a mirror.

    Science.gov (United States)

    Pelliccia, Daniele; Paganin, David M

    2014-04-01

    Multi-modal hard x-ray imaging sensitive to absorption, refraction, phase and scattering contrast is demonstrated using a simple setup implemented with a laboratory source. The method is based on selective reflection at the edge of a mirror, aligned to partially reflect a pencil x-ray beam after its interaction with a sample. Quantitative scattering contrast from a test sample is experimentally demonstrated using this method. Multi-modal imaging of a house fly (Musca domestica) is shown as proof of principle of the technique for biological samples.

  16. Improved Contact X-Ray Microradiographic Method to Measure Mineral Density of Hard Dental Tissues

    OpenAIRE

    Schmuck, B.D.; Carey, C.M.

    2010-01-01

    Contact X-ray microradiography is the current gold standard for measuring mineral densities of partially demineralized tooth specimens. The X-ray sensitive film specified in the last J Res NIST publication on the subject is no longer commercially available.

  17. Experimental study on hard X-rays emitted from metre-scale negative discharges in air

    NARCIS (Netherlands)

    Kochkin, P.O.; Deursen, A. van; Ebert, U.

    2015-01-01

    We investigate the development of metre long negative discharges and focus on their x-ray emissions. We describe appearance, timing and spatial distribution of the x-rays. They appear in bursts of nanosecond duration mostly in the cathode area. The spectrum can be characterized by an exponential fun

  18. The Palermo Swift-BAT hard X-ray catalogue III. Results after 54 months of sky survey

    CERN Document Server

    Cusumano, G; Segreto, A; Ferrigno, C; Maselli, A; Sbarufatti, B; Romano, P; Chincarini, G; Giommi, P; Masetti, N; Moretti, A; Parisi, P; Tagliaferri, G

    2010-01-01

    We present the Second Palermo Swift-BAT hard X-ray catalogue obtained by analysing data acquired in the first 54 months of the Swift mission. Using our software dedicated to the analysis of data from coded mask telescopes, we analysed the BAT survey data in three energy bands (15-30 keV, 15-70 keV, 15-150 keV), obtaining a list of 1256 detections above a significance threshold of 4.8 standard deviations. The identification of the source counterparts is pursued using two strategies: the analysis of field observations of soft X-ray instruments and cross-correlation of our catalogue with source databases.The survey covers 50% of the sky to a 15--150 keV flux limit of 1.0 x 10^-11 erg s^-1 cm^-2 and 9.2 x 10^-12 erg s^-1 cm^-2 for |b| 10 degrees, respectively. The Second Palermo Swift-BAT hard X-ray catalogue includes 1079 (86%) hard X-ray sources with an associated counterpart (26 with a double association and 2 with a triple association) and 177 BAT excesses (14%) that still lack a counterpart. The distribution...

  19. Correlations of the IR Luminosity and Eddington Ratio with a Hard X-ray Selected Sample of AGN

    Science.gov (United States)

    Mushotzy, Richard F.; Winter, Lisa M.; McIntosh, Daniel H.; Tueller, Jack

    2008-01-01

    We use the SWIFT Burst Alert Telescope (BAT) sample of hard x-ray selected active galactic nuclei (AGN) with a median redshift of 0.03 and the 2MASS J and K band photometry to examine the correlation of hard x-ray emission to Eddington ratio as well as the relationship of the J and K band nuclear luminosity to the hard x-ray luminosity. The BAT sample is almost unbiased by the effects of obscuration and thus offers the first large unbiased sample for the examination of correlations between different wavelength bands. We find that the near-IR nuclear J and K band luminosity is related to the BAT (14 - 195 keV) luminosity over a factor of 10(exp 3) in luminosity (L(sub IR) approx.equals L(sub BAT)(sup 1.25) and thus is unlikely to be due to dust. We also find that the Eddington ratio is proportional to the x-ray luminosity. This new result should be a strong constraint on models of the formation of the broad band continuum.

  20. Development of a hard x-ray focal plane compton polarimeter: a compact polarimetric configuration with scintillators and Si photomultipliers

    Science.gov (United States)

    Chattopadhyay, T.; Vadawale, S. V.; Goyal, S. K.; Mithun, N. P. S.; Patel, A. R.; Shukla, R.; Ladiya, T.; Shanmugam, M.; Patel, V. R.; Ubale, G. P.

    2016-02-01

    X-ray polarization measurement of cosmic sources provides two unique parameters namely degree and angle of polarization which can probe the emission mechanism and geometry at close vicinity of the compact objects. Specifically, the hard X-ray polarimetry is more rewarding because the sources are expected to be intrinsically highly polarized at higher energies. With the successful implementation of Hard X-ray optics in NuSTAR, it is now feasible to conceive Compton polarimeters as focal plane detectors. Such a configuration is likely to provide sensitive polarization measurements in hard X-rays with a broad energy band. We are developing a focal plane hard X-ray Compton polarimeter consisting of a plastic scintillator as active scatterer surrounded by a cylindrical array of CsI(Tl) scintillators. The scatterer is 5 mm diameter and 100 mm long plastic scintillator (BC404) viewed by normal PMT. The photons scattered by the plastic scatterer are collected by a cylindrical array of 16 CsI(Tl) scintillators (5 mm × 5 mm × 150 mm) which are read by Si Photomultiplier (SiPM). Use of the new generation SiPMs ensures the compactness of the instrument which is essential for the design of focal plane detectors. The expected sensitivity of such polarimetric configuration and complete characterization of the plastic scatterer, specially at lower energies have been discussed in [11, 13]. In this paper, we characterize the CsI(Tl) absorbers coupled to SiPM. We also present the experimental results from the fully assembled configuration of the Compton polarimeter.

  1. The low-high-low trend of type III radio burst starting frequencies and solar flare hard X-rays

    Science.gov (United States)

    Reid, Hamish A. S.; Vilmer, Nicole; Kontar, Eduard P.

    2014-07-01

    Aims: Using simultaneous X-ray and radio observations from solar flares, we investigate the link between the type III radio burst starting frequency and hard X-ray spectral index. For a proportion of events the relation derived between the starting height (frequency) of type III radio bursts and the electron beam velocity spectral index (deduced from X-rays) is used to infer the spatial properties (height and size) of the electron beam acceleration region. Both quantities can be related to the distance travelled before an electron beam becomes unstable to Langmuir waves. Methods: To obtain a list of suitable events we considered the RHESSI catalogue of X-ray flares and the Phoenix 2 catalogue of type III radio bursts. From the 200 events that showed both type III and X-ray signatures, we selected 30 events which had simultaneous emission in both wavelengths, good signal to noise in the X-ray domain and >20 s duration. Results: We find that >50% of the selected events show a good correlation between the starting frequencies of the groups of type III bursts and the hard X-ray spectral indices. A low-high-low trend for the starting frequency of type III bursts is frequently observed. Assuming a background electron density model and the thick target approximation for X-ray observations, this leads to a correlation between starting heights of the type III emission and the beam electron spectral index. Using this correlation we infer the altitude and vertical extents of the flare acceleration regions. We find heights from 183 Mm down to 25 Mm while the sizes range from 13 Mm to 2 Mm. These values agree with previous work that places an extended flare acceleration region high in the corona. We also analyse the assumptions that are required to obtain our estimates and explore possible extensions to our assumed model. We discuss these results with respect to the acceleration heights and sizes derived from X-ray observations alone. Appendices are available in electronic form

  2. 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

  3. Damage threshold of platinum/carbon multilayers under hard X-ray free-electron laser irradiation.

    Science.gov (United States)

    Kim, Jangwoo; Nagahira, Ayaka; Koyama, Takahisa; Matsuyama, Satoshi; Sano, Yasuhisa; Yabashi, Makina; Ohashi, Haruhiko; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2015-11-01

    We evaluated the irradiation damage induced by hard X-ray free-electron lasers to platinum/carbon multilayers intended for use in a focusing reflective mirror. In order to determine the damage threshold, we compared X-ray reflectivities before and after irradiation at the first-order Bragg angle using a focused X-ray free-electron laser with a beam size of approximately 1 μm and a pulse energy ranging from 0.01 to 10 μJ at a photon energy of 10 keV. We confirmed that the damage threshold of the platinum/carbon multilayer with a bilayer period of 3 nm was 0.051 μJ/μm(2), which is sufficiently higher than that in practical applications.

  4. Time-resolved hard X-Ray hardness variation of solar flares observed by Suzaku Wide-band All-sky monitor

    OpenAIRE

    遠藤, 輝; Endo, Akira; 守上, 浩市; Morigami, Kouichi; 田代, 信; Tashiro, Makoto; 寺田, 幸功; Terada, Yukikatsu; 山岡, 和貴; Yamaoka, Kazutaka; 園田 絵里; Sonoda, Eri; 簑島, 敬; Minoshima, Takashi; Krucker, Sam

    2010-01-01

    Results of solar flare observations in the hard X-ray band with the Suzaku Wide-band All-sky Monitor (WAM) are reported. On June 2009, 108 solar flares (GOES class X:16, M:29, C:46, B:17) have been detected with the WAM since the launch. One of the brightest flares WAM detected was the event occurring on 2006 December 13. It lasted for more than 700 seconds even in above 500 keV. This event was simultaneously observed by the solar missions Hinode and RHESSI in soft and hard X-ray region respe...

  5. Probing the hard and intermediate states of X-ray binaries using short time-scale variability

    CERN Document Server

    Skipper, Chris J

    2016-01-01

    Below an accretion rate of approximately a few per cent of the Eddington accretion rate, X-ray binary systems are not usually found in the soft spectral state. However, at accretion rates a factor of a few lower still, in the hard state, there is another spectral transition which is well observed but not well understood. Below ~0.5-1 per cent of the Eddington accretion rate (m_crit), the spectral index hardens with increasing accretion rate, but above m_crit, although still in the hard state, the spectral index softens with increasing accretion rate. Here we use a combination of X-ray spectral fitting and a study of short time-scale spectral variability to examine the behaviour of three well-known X-ray binaries: Cygnus X-1, GX 339-4 and XTE J1118+480. In Cygnus X-1 we find separate hard and soft continuum components, and show using root-mean-square (rms) spectra that the soft component dominates the variability. The spectral transition at m_crit is clearly present in the hard-state hardness-intensity diagram...

  6. Radio/X-ray correlation in the low/hard state of GX 339-4

    OpenAIRE

    Corbel, S.; Nowak, M A; Fender, R. P.; Tzioumis, A. K.; Markoff, S. B.

    2003-01-01

    We present the results of a long-term study of the black hole candidate GX 339-4 using simultaneous radio (from the Australia Telescope Compact Array) and X-ray (from the Rossi X-ray Timing Explorer and BeppoSAX) observations performed between 1997 and 2000. We find strong evidence for a correlation between these two emission regimes that extends over more than three decades in X-ray flux, down to the quiescence level of GX 339-4. This is the strongest evidence to date for such strong couplin...

  7. The large-scale bias of the hard X-ray background

    OpenAIRE

    Boughn, S.; Crittenden, Robert

    2004-01-01

    Recent deep X-ray surveys combined with spectroscopic identification of the sources have allowed the determination of the rest-frame 2-8 keV luminosity as a function of redshift. In addition, an analysis of the HEAO1 A2 2-10 keV full-sky map of the X-ray background (XRB) reveals clustering on the scale of several degrees. Combining these two results in the context of the currently favored Lambda-CDM cosmological model implies an average X-ray bias factor, b_x, of b_x^2 = 1.12 +- 0.33, i.e., b...

  8. A "high-hard" outburst of the black hole X-ray binary GS 1354-64

    Science.gov (United States)

    Koljonen, Karri; Russell, David; Corral-Santana, Jesus; Armas Padilla, Montserrat; Munoz-Darias, Teo; Lewis, Fraser

    2016-06-01

    In the shadows of the V404 Cyg outburst in the summer of 2015, GS 1354-64 (BW Cir) went into outburst as well. We followed the evolution of the outburst at optical, UV and X-ray wavelengths using Faulkes Telescope South, SMARTS and Swift. The outburst was found to stay in the hard X-ray state, albeit being anomalously luminous with a peak X-ray luminosity exceeding 0.15 LEdd, which could be the most luminous hard state observed in a black hole X-ray binary. In this talk I will present our results showing that the the outburst evolution at all wavelengths can be explained by the disk instability model with irradiation and disk evaporation/condensation. In addition, I will present our long-term optical monitoring results that show a statistically significant, slow rise of the source brightness over the 7 years prior to the 2015 outburst. This could be the much-sought observational evidence of matter slowly accumulating in the accretion disk, and subsequently getting optically brighter, as predicted by the disk instability model.

  9. Violent Hard X-ray Variability of Mrk 421 Observed by NuSTAR in 2013 April

    CERN Document Server

    Paliya, Vaidehi S; Diltz, Chris; Stalin, C S; Sahayanathan, S; Ravikumar, C D

    2015-01-01

    The well studied blazar Markarian 421 (Mrk 421, $z$=0.031) was the subject of an intensive multi-wavelength campaign when it flared in 2013 April. The recorded X-ray and very high energy (VHE, E$>$100 GeV) $\\gamma$-ray fluxes are the highest ever measured from this object. At the peak of the activity, it was monitored by the hard X-ray focusing telescope {\\it Nuclear Spectroscopic Telescope Array} ({\\it NuSTAR}) and {\\it Swift} X-Ray Telescope (XRT). In this work, we present a detailed variability analysis of {\\it NuSTAR} and {\\it Swift}-XRT observations of Mrk 421 during this flaring episode. We obtained the shortest flux doubling time of 14.01$\\pm$5.03 minutes, which is the shortest hard X-ray (3$-$79 keV) variability ever recorded from Mrk 421 and is on the order of the light crossing time of the black hole's event horizon. A pattern of extremely fast variability events superposed on slowly varying flares is found in most of the {\\it NuSTAR} observations. We suggest that these peculiar variability patterns...

  10. Thin-film-based scintillators for hard x-ray microimaging detectors: the ScinTAX Project

    Science.gov (United States)

    Rack, A.; Cecilia, A.; Douissard, P.-A.; Dupré, K.; Wesemann, V.; Baumbach, T.; Couchaud, M.; Rochet, X.; Riesemeier, H.; Radtke, M.; Martin, T.

    2014-09-01

    The project ScinTAX developed novel thin scintillating films for the application in high performance X-ray imaging and subsequent introduced new X-ray detectors to the market. To achieve this aim lutetium orthosilicate (LSO) scintillators doped with different activators were grown successfully by liquid phase epitaxy. The high density of LSO (7.4 g/cm3), the effective atomic number (65.2) and the high light yield make this scintillator highly applicable for indirect X-ray detection in which the ionizing radiation is converted into visible light and then registered by a digital detector. A modular indirect detection system has been developed to fully exploit the potential of this thin film scintillator for radiographic and tomographic imaging. The system is compatible for high-resolution imaging with moderate dose as well as adaptable to intense high-dose applications where radiation hard microimaging detectors are required. This proceedings article shall review the achieved performances and technical details on this high-resolution detector system which is now available. A selected example application demonstrates the great potential of the optimized detector system for hard X-ray microimaging, i.e. either to improve image contrast due to the availability of efficient thin crystal films or to reduce the dose to the sample.

  11. Spherical-Wave Far-Field Interferometer for Hard X-Ray Phase Contrast Imaging

    CERN Document Server

    Miao, Houxun; Harmon, Katherine J; Bennett, Eric E; Chedid, Nicholas; Panna, Alireza; Bhandarkar, Priya; Wen, Han

    2014-01-01

    Low dose, high contrast x-ray imaging is of general interest in medical diagnostic applications. X-ray Mach-Zehnder interferometers using collimated synchrotron beams demonstrate the highest levels of phase contrast under a given exposure dose. However, common x-ray sources emit divergent cone beams. Here, we developed a spherical-wave inline Mach-Zehnder interferometer for phase contrast imaging over an extended area with a broadband and divergent source. The first tabletop system was tested in imaging experiments of a mammographic accreditation phantom and various biological specimens. The noise level of the phase contrast images at a clinical radiation dose corresponded to a 6 nano radian bending of the x-ray wavefront. Un-resolved structures with conventional radiography and near-field interferometer techniques became visible at a fraction of the radiation dose.

  12. Hard X-ray Detector Calibrations for the FOXSI Sounding Rocket

    Science.gov (United States)

    Lopez, A.; Glesener, L.; Buitrago Casas, J. C.; Han, R.; Ishikawa, S. N.; Christe, S.; Krucker, S.

    2015-12-01

    In the study of high-energy solar flares, detailed X-ray images and spectra of the Sun are required. The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket experiment is used to test direct-focusing X-ray telescopes and Double-sided Silicon Strip Detectors (DSSD) for solar flare study and to further understand coronal heating. The measurement of active region differential emission measures, flare temperatures, and possible quiet-Sun emission requires a precisely calibrated spectral response. This poster describes recent updates in the calibration of FOXSI's DSSDs based on new calibration tests that were performed after the second flight. The gain for each strip was recalculated using additional radioactive sources. Additionally, the varying strip sensitivity across the detectors was investigated and based on these measurements, the flight images were flatfielded. These improvements lead to more precise X-ray data for future FOXSI flights and show promise for these new technologies in imaging the Sun.

  13. Spatially resolved hard X-ray polarization in solar flares: effects of Compton scattering and bremsstrahlung

    Science.gov (United States)

    Jeffrey, N. L. S.; Kontar, E. P.

    2011-12-01

    Aims: We study the polarization of hard X-ray (HXR) sources in the solar atmosphere, including Compton backscattering of photons in the photosphere (the albedo effect) and the spatial distribution of polarization across the source. Methods: HXR photon polarization and spectra produced via electron-ion bremsstrahlung emission are calculated from various electron distributions typical for solar flares. Compton scattering and photoelectric absorption are then modelled using Monte Carlo simulations of photon transport in the photosphere to study the observed (primary and albedo) sources. Polarization maps across HXR sources (primary and albedo components) for each of the modelled electron distributions are calculated at various source locations from the solar centre to the limb. Results: We show that Compton scattering produces a distinct polarization variation across the albedo patch at peak albedo energies of 20-50 keV for all anisotropies modelled. The results show that there are distinct spatial polarization changes in both the radial and perpendicular to radial directions across the extent of the HXR source at a given disk location. In the radial direction, the polarization magnitude and direction at specific positions along the HXR source will either increase or decrease with increased photon distribution directivity towards the photosphere. We also show how high electron cutoff energies influence the direction of polarization at above ~100 keV. Conclusions: Spatially resolved HXR polarization measurements can provide important information about the directivity and energetics of the electron distribution. Our results indicate the preferred angular resolution of polarization measurements required to distinguish between the scattered and primary components. We also show how spatially resolved polarization measurements could be used to probe the emission pattern of an HXR source, using both the magnitude and the direction of the polarization.

  14. SOLAR HARD X-RAY SOURCE SIZES IN A BEAM-HEATED AND IONIZED CHROMOSPHERE

    International Nuclear Information System (INIS)

    Solar flare hard X-rays (HXRs) are produced as bremsstrahlung when an accelerated population of electrons interacts with the dense chromospheric plasma. HXR observations presented by Kontar et al. using the Ramaty High-Energy Solar Spectroscopic Imager have shown that HXR source sizes are three to six times more extended in height than those predicted by the standard collisional thick target model (CTTM). Several possible explanations have been put forward including the multi-threaded nature of flare loops, pitch-angle scattering, and magnetic mirroring. However, the nonuniform ionization (NUI) structure along the path of the electron beam has not been fully explored as a solution to this problem. Ionized plasma is known to be less effective at producing nonthermal bremsstrahlung HXRs when compared to neutral plasma. If the peak HXR emission was produced in a locally ionized region within the chromosphere, the intensity of emission will be preferentially reduced around this peak, resulting in a more extended source. Due to this effect, along with the associated density enhancement in the upper chromosphere, injection of a beam of electrons into a partially ionized plasma should result in an HXR source that is substantially more vertically extended relative to that for a neutral target. Here we present the results of a modification to the CTTM, which takes into account both a localized form of chromospheric NUI and an increased target density. We find 50 keV HXR source widths, with and without the inclusion of a locally ionized region, of ∼3 Mm and ∼0.7 Mm, respectively. This helps to provide a theoretical solution to the currently open question of overly extended HXR sources

  15. 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.

  16. Hard X-Ray Flare Source Sizes Measured with the Ramaty High Energy Solar Spectroscopic Imager

    Science.gov (United States)

    Dennis, Brian R.; Pernak, Rick L.

    2009-01-01

    Ramaty High Energy Solar Spectroscopic Imager (RHESSI) observations of 18 double hard X-ray sources seen at energies above 25 keV are analyzed to determine the spatial extent of the most compact structures evident in each case. The following four image reconstruction algorithms were used: Clean, Pixon, and two routines using visibilities maximum entropy and forward fit (VFF). All have been adapted for this study to optimize their ability to provide reliable estimates of the sizes of the more compact sources. The source fluxes, sizes, and morphologies obtained with each method are cross-correlated and the similarities and disagreements are discussed. The full width at half-maximum (FWHM) of the major axes of the sources with assumed elliptical Gaussian shapes are generally well correlated between the four image reconstruction routines and vary between the RHESSI resolution limit of approximately 2" up to approximately 20" with most below 10". The FWHM of the minor axes are generally at or just above the RHESSI limit and hence should be considered as unresolved in most cases. The orientation angles of the elliptical sources are also well correlated. These results suggest that the elongated sources are generally aligned along a flare ribbon with the minor axis perpendicular to the ribbon. This is verified for the one flare in our list with coincident Transition Region and Coronal Explorer (TRACE) images. There is evidence for significant extra flux in many of the flares in addition to the two identified compact sources, thus rendering the VFF assumption of just two Gaussians inadequate. A more realistic approximation in many cases would be of two line sources with unresolved widths. Recommendations are given for optimizing the RHESSI imaging reconstruction process to ensure that the finest possible details of the source morphology become evident and that reliable estimates can be made of the source dimensions.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-01

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

  18. SOLAR HARD X-RAY SOURCE SIZES IN A BEAM-HEATED AND IONIZED CHROMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    O' Flannagain, Aidan M.; Gallagher, Peter T. [Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Brown, John C. [Astronomy and Astrophysics Group, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2015-02-01

    Solar flare hard X-rays (HXRs) are produced as bremsstrahlung when an accelerated population of electrons interacts with the dense chromospheric plasma. HXR observations presented by Kontar et al. using the Ramaty High-Energy Solar Spectroscopic Imager have shown that HXR source sizes are three to six times more extended in height than those predicted by the standard collisional thick target model (CTTM). Several possible explanations have been put forward including the multi-threaded nature of flare loops, pitch-angle scattering, and magnetic mirroring. However, the nonuniform ionization (NUI) structure along the path of the electron beam has not been fully explored as a solution to this problem. Ionized plasma is known to be less effective at producing nonthermal bremsstrahlung HXRs when compared to neutral plasma. If the peak HXR emission was produced in a locally ionized region within the chromosphere, the intensity of emission will be preferentially reduced around this peak, resulting in a more extended source. Due to this effect, along with the associated density enhancement in the upper chromosphere, injection of a beam of electrons into a partially ionized plasma should result in an HXR source that is substantially more vertically extended relative to that for a neutral target. Here we present the results of a modification to the CTTM, which takes into account both a localized form of chromospheric NUI and an increased target density. We find 50 keV HXR source widths, with and without the inclusion of a locally ionized region, of ∼3 Mm and ∼0.7 Mm, respectively. This helps to provide a theoretical solution to the currently open question of overly extended HXR sources.

  19. Real-time algorithms for JET hard X-ray and gamma-ray profile monitor

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, A., E-mail: anaf@ipfn.ist.utl.pt [Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa (Portugal); Pereira, R.C.; Valcárcel, D.F.; Alves, D.; Carvalho, B.B.; Sousa, J. [Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa (Portugal); Kiptily, V. [EURATOM/CCFE Fusion Association, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Correia, C.M.B.A. [Centro de Instrumentação, Dept. de Física, Universidade de Coimbra, 3004-516 Coimbra (Portugal); Gonçalves, B. [Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa (Portugal)

    2014-03-15

    Highlights: • Real-time tools and mechanisms are required for data handling and machine control. • A new DAQ system, ATCA based, with embedded FPGAs, was installed at JET. • Different real-time algorithms were developed for FPGAs and MARTe application. • MARTe provides the interface to CODAS and to the JET real-time network. • The new DAQ system is capable to process and deliver data in real-time. - Abstract: The steady state operation with high energy content foreseen for future generation of fusion devices will necessarily demand dedicated real-time tools and mechanisms for data handling and machine control. Consequently, the real-time systems for those devices should be carefully selected and their capabilities previously established. The Joint European Torus (JET) is undertaking an enhancement program, which includes tests of relevant real-time tools for the International Thermonuclear Experimental Reactor (ITER), a key experiment for future fusion devices. In these enhancements a new Data AcQuisition (DAQ) system is included, with real-time processing capabilities, for the JET hard X-ray and gamma-ray profile monitor. The DAQ system is composed of dedicated digitizer modules with embedded Field Programmable Gate Array (FPGA) devices. The interface between the DAQ system, the JET control and data acquisition system and the JET real-time data network is provided by the Multithreaded Application Real-Time executor (MARTe). This paper describes the real-time algorithms, developed for both digitizers’ FPGAs and MARTe application, capable of meeting the DAQ real-time requirements. The new DAQ system, including the embedded real-time features, was commissioned during the 2012 experiments. Results achieved with these real-time algorithms during experiments are presented.

  20. Sub-500  nm hard x ray focusing by compound long kinoform lenses.

    Science.gov (United States)

    Liao, Keliang; Liu, Jing; Liang, Hao; Wu, Xuehui; Zhang, Kai; Yuan, Qingxi; Yi, Futing; Sheng, Weifan

    2016-01-01

    The focusing performance of polymethyl methacrylate compound long kinoform lenses with 70 μm aperture and 19.5 mm focal length was characterized with 8 keV x rays using the knife-edge scan method at the 4W1A transmission x-ray microscope beamline of Beijing Synchrotron Radiation Facility. The experiment result shows a best FWHM focus size of 440 nm with 31% diffraction efficiency. PMID:26835618

  1. Swift J2218.4+1925: a new hard-X-ray-selected polar observed with XMM-Newton

    Science.gov (United States)

    Bernardini, F.; de Martino, D.; Mukai, K.; Falanga, M.

    2014-12-01

    Swift J2218.4+1925, a hard-X-ray source detected by Swift Burst Alert Telescope (BAT), has been proposed as a candidate magnetic cataclysmic variable of the polar type from optical spectroscopy. Using XMM-Newton we perform detailed timing and spectral analysis with simultaneous X-ray (0.3-10 keV) and optical B-band data. We complement the spectral study with archival hard-X-ray (14-70 keV) spectra collected by Swift BAT as well as with optical, near and mid-infrared photometry from Sloan Digital Sky Survey, Two-Micron All Sky Survey and Wide-field Infrared Survey Explorer archive, respectively. A strong periodic X-ray signal at 2.16 h, fully consistent with the recently determined spectroscopic orbital period, adds Swift J2218.4+1925 to the small group of hard-X-ray polars and locates it at the low edge of the orbital period gap. The X-ray pulse profile shows the typical bright and faint phases seen in polars, that last ˜70 and ˜30 per cent of the orbit, respectively. A pronounced dip centred on the bright phase is also detected. It is stronger at lower energies and is mainly produced by photoelectric absorption. A binary inclination i ˜ 40°-50° and a magnetic colatitude β ˜ 55°-64° are estimated. The source appears to accrete over a large area ˜24° wide. A multitemperature optically thin emission with complex absorption well describes the broad-band (0.3-70 keV) spectrum, with no signs of a soft X-ray blackbody component. The spectral shape strongly varies with the source rotation reaching plasma temperatures up to 55 keV, hardening at the dip and being softer during the faint phase (˜7 keV). We also find the first indication of an absorption edge due to a warm absorber in a polar. Indication of overabundance of neon is found in the Reflection Grating Spectrometer (RGS) spectra. The UV to mid-IR spectral energy distribution reveals an excess in the near and mid-IR, likely due to low cyclotron harmonics. We further estimate a white dwarf mass of 0.97 M

  2. Establishment of medium-hard x-ray reference fields for performance tests of radiation measuring instruments based on national standard

    International Nuclear Information System (INIS)

    In the Japanese Industrial Standard, JIS Z 4511 sets the condition of X-ray reference fields to be used for the performance test of radiation measuring instruments for radiation protection. We renewed a X-ray tube of the medium-hard X-ray irradiation device that was damaged in the Facility of Radiation Standards in Nuclear Science Research Institute. Therefore, we established four series of medium-hard X-ray reference fields with quality index of 0.6, 0.7, 0.8 and 0.9 based on JIS Z 4511. In this article, quality of the X-ray fields, X-ray spectra, conversion coefficients to the dose equivalents from Air-kerma were evaluated in the medium-hard X-ray fields produced with X-ray tube voltage ranging from 20 kV to 300 kV, and set about 52 qualities of medium-hard X-ray reference fields based on JIS Z 4511. These X-ray reference fields were well adapted to a setting condition of JIS and precision of conversion factors to various dose equivalents from Air-kerma was good. We also confirmed the soundness of the spectrum of each X-ray quality. As a result, medium-hard X-ray reference fields were established that can provide the dose equivalent standard with good precision and wide range of test energy points and dose rates, for the performance tests such as the energy characteristic and the direction characteristic for various radiation measuring instruments. We clarified these detailed data. (author)

  3. Time resolved, 2-D hard X-ray imaging of relativistic electron-beam target interactions on ETA-II

    International Nuclear Information System (INIS)

    Advanced radiographic applications require a constant source size less than 1 mm. To study the time history of a relativistic electron beam as it interacts with a bremsstrahlung converter, one of the diagnostics they use is a multi-frame time-resolved hard x-ray camera. They are performing experiments on the ETA-II accelerator at Lawrence Livermore National Laboratory to investigate details of the electron beam/converter interactions. The camera they are using contains 6 time-resolved images, each image is a 5 ns frame. By starting each successive frame 10 ns after the previous frame, they create a 6-frame movie from the hard x-rays produced from the interaction of the 50-ns electron beam pulse

  4. Study of expected performance of the hard X-ray beam for the FEL-X project

    CERN Document Server

    Sei, N; Ohgaki, H; Mikado, T; Yasumoto, M; Ogawa, H

    2002-01-01

    We advance the FEL-X project and plan to install a new optical klystron for the infrared FELs within next year. The expected FEL gain at a wavelength of 10.6 mu m is over 2% with the present electron-beam qualities in the storage ring NIJI-IV. Infrared FELs based on the fundamental and higher harmonics from the new optical klystron will generate hard X-ray beams with an energy of 0.1-2 MeV by the FEL-Compton backscattering process. Conventional light sources cannot provide sufficient amounts of photons in this energy region. The expected yield of the hard X-ray beam is 10 sup 5 -10 sup 6 per second with an energy spread of 3%.

  5. Penetrating view of nano-structures in Aleochara verna spermatheca and flagellum by hard X-ray microscopy

    Institute of Scientific and Technical Information of China (English)

    Zhang Kai; Li De-E; Hong You-Li; Zhu Pei-Ping; Yuan Qing-Xi; Huang Wan-Xia; Gao Kun

    2013-01-01

    A penetrating view of the three-dimensional nanostructure of female spermatheca and male flagellum in the species Aleochara verna is obtained with 100-nm resolution using a hard X-ray microscope,which provides a fast noninvasive imaging technology for insect morphology.Through introducing Zernike phase contrast and heavy metal staining,images taken at 8 keV displayed sufficient contrast for observing nanoscale fine structures,such as the spermatheca cochleate duct and the subapex of the flagellum,which have some implications for the study of the sperm transfer process and genital evolution in insects.This work shows that both the spatial resolution and the contrast characteristic of hard X-ray microscopy are quite promising for insect morphology studies and,particularly,provide an attractive alternative to the destructive techniques used for investigating internal soft tissues.

  6. Visualization of electrochemically driven solid-state phase transformations using operando hard X-ray spectro-imaging

    OpenAIRE

    Li, Linsen; Chen-Wiegart, Yu-chen Karen; Wang, Jiajun; Gao, Peng; Ding, Qi; Yu, Young-Sang; Wang, Feng; Cabana, Jordi; Wang, Jun; Jin, Song

    2015-01-01

    In situ techniques with high temporal, spatial and chemical resolution are key to understand ubiquitous solid-state phase transformations, which are crucial to many technological applications. Hard X-ray spectro-imaging can visualize electrochemically driven phase transformations but demands considerably large samples with strong absorption signal so far. Here we show a conceptually new data analysis method to enable operando visualization of mechanistically relevant weakly absorbing samples ...

  7. A New Method for Investigation of the Hair Shaft: Hard X-Ray Microscopy with a 90-nm Spatial Resolution

    OpenAIRE

    Jeon, Soo-Young; Goo, Ja Woong; Hong, Seung Phil; Oh, Tak Heon; Youn, Hwa Shik; Lee, Won-Soo

    2008-01-01

    Various methods have been used to investigate the hair shaft. In the ultrastructural hair field, scanning and transmission electron microscopies are widely used investigative methods, but they have some technical limitations. Recently, X-ray microscopes with sub-micron spatial resolution have emerged as useful instruments because they offer a unique opportunity to observe the interior of an undamaged sample in greater detail. In this report, we examined damaged hair shaft tips using hard X-ra...

  8. Efficient high-resolution hard x-ray imaging with transparent Lu2O3:Eu scintillator thin films

    Science.gov (United States)

    Marton, Zsolt; Miller, Stuart R.; Brecher, Charles; Kenesei, Peter; Moore, Matthew D.; Woods, Russell; Almer, Jonathan D.; Miceli, Antonino; Nagarkar, Vivek V.

    2015-09-01

    We have developed microstructured Lu2O3:Eu scintillator films that provide spatial resolution on the order of micrometers for hard X-ray imaging. In addition to their outstanding resolution, Lu2O3:Eu films also exhibits both high absorption efficiency for 20 to 100 keV X-rays, and bright 610 nm emission whose intensity rivals that of the brightest known scintillators. At present, high spatial resolution of such a magnitude is achieved using ultra-thin scintillators measuring only about 1 to 5 μm in thickness, which limits absorption efficiency to ~3% for 12 keV X-rays and less than 0.1% for 20 to 100 keV X-rays; this results in excessive measurement time and exposure to the specimen. But the absorption efficiency of Lu2O3:Eu (99.9% @12 keV and 30% @ 70 keV) is much greater, significantly decreasing measurement time and radiation exposure. Our Lu2O3:Eu scintillator material, fabricated by our electron-beam physical vapor deposition (EB-PVD) process, combines superior density of 9.5 g/cm3, a microcolumnar structure for higher spatial resolution, and a bright emission (48000 photons/MeV) whose wavelength is an ideal match for the underlying CCD detector array. We grew thin films of this material on a variety of matching substrates, measuring some 5-10μm in thickness and covering areas up to 1 x 1 cm2, which can be a suitable basis for microtomography, digital radiography as well as CT and hard X-ray Micro-Tomography (XMT). The microstructure and optical transparency of such screens was optimized, and their imaging performance was evaluated in the Argonne National Laboratory's Advanced Photon Source. Spatial resolution and efficiency were also characterized.

  9. Practical chemical analysis of Pt and Pd based heterogeneous catalysts with hard X-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Highlights: •Hard X-ray photoelectron spectroscopy (HAXPES) enables interface analysis of catalyst. •HAXPES enables overall analysis of porous film of Pt-doped CeO2 and related catalyst. •HAXPES enables analysis of trace elements for Pd and Pt3Ni nanoparticle catalysts. -- Abstract: Interfacial properties including configuration, porosity, chemical states, and atomic diffusion greatly affect the performance of supported heterogeneous catalysts. Hard X-ray photoelectron spectroscopy (HAXPES) can be used to analyze the interfaces of heterogeneous catalysts because of its large information depth of more than 20 nm. We use HAXPES to examine Pt-doped CeO2 and related thin film catalysts evaporated on Si, carbon, and carbon nanotube substrates, because Pt-doped CeO2 has great potential as a noble metal-based heterogeneous catalyst for fuel cells. The HAXPES measurements clarify that the dopant material, substrate material, and surface pretreatment of substrate are important parameters that affect the interfacial properties of Pt-doped CeO2 and related thin film catalysts. Another advantage of HAXPES measurement of heterogeneous catalysts is that it can be used for chemical analysis of trace elements by detecting photoelectrons from deep core levels, which have large photoionization cross-sections in the hard X-ray region. We use HAXPES for chemical analysis of trace elements in Pd nanoparticle catalysts immobilized on sulfur-terminated substrates and Pt3Ni nanoparticle catalysts enveloped by dendrimer molecules

  10. Analysis of intermittency in submillimeter radio and Hard X-Rays during the impulsive phase of a solar flare

    CERN Document Server

    de Castro, C Guillermo Giménez; Raulin, Jean-Pierre; Guimarães, Odilon M

    2016-01-01

    We present an analysis of intermittent processes occurred during the impulsive phase of the flare SOL2012-03-13, using hard X-rays and submillimeter radio data. Intermittency is a key characteristic in turbulent plasmas and have been a analyzed recently for Hard X-rays data only. Since in a typical flare the same accelerated electron population is believed to produce both Hard X-rays and gyrosynchrotron, we compare both time profiles searching for intermittency signatures. For that we define a cross-wavelet power spectrum, that is used to obtain the Local Intermittency Measure or LIM. When greater than 3, the square LIM coefficients indicate a local intermittent process. The LIM$^2$ coefficient distribution in time and scale helps to identify avalanche or cascade energy release processes. We find two different and well separated intermittent behaviors in the submillimeter data: for scales greater than 20 s, a broad distribution during the rising and maximum phases of the emission seems to favor a cascade proc...

  11. Modeling the flaring activity of the high z, hard X-ray selected blazar IGR J22517+2217

    CERN Document Server

    Lanzuisi, G; Ghisellini, G; Ubertini, P; Panessa, F; Ajello, M; Bassani, L; Fukazawa, Y; D'Ammando, F

    2011-01-01

    We present new Suzaku and Fermi data, and re-analyzed archival hard X-ray data from INTEGRAL and Swift-BAT survey, to investigate the physical properties of the luminous, high-redshift, hard X-ray selected blazar IGR J22517+2217, through the modelization of its broad band spectral energy distribution (SED) in two different activity states. Through the analysis of the new Suzaku data and the flux selected data from archival hard X-ray observations, we build the source SED in two different states, one for the newly discovered flare occurred in 2005 and one for the following quiescent period. Both SEDs are strongly dominated by the high energy hump peaked at 10^20 -10^22 Hz, that is at least two orders of magnitude higher than the low energy (synchrotron) one at 10^11 -10^14 Hz, and varies by a factor of 10 between the two states. In both states the high energy hump is modeled as inverse Compton emission between relativistic electrons and seed photons produced externally to the jet, while the synchrotron self-Co...

  12. The origin of the puzzling hard X-ray emission of $\\gamma$ Cassiopeiae

    CERN Document Server

    Motch, Christian; Smith, Myron A

    2015-01-01

    Massive B and Be stars produce X-rays from shocks in high velocity winds with temperatures of a few million degrees and maximum X-ray luminosities of $\\approx$ 10$^{31}$ erg/s. Surprisingly, a sub-group of early Be stars exhibits > 20 times hotter X-ray temperatures and > 10 times higher X-ray luminosities than normal. This group of Be stars, dubbed Gamma-Cas analogs, contains about 10 known objects. The origin of this bizarre behavior has been extensively debated in the past decades. Two mechanisms have been put forward, accretion of circumstellar disk matter onto an orbiting white dwarf, or magnetic field interaction between the star and the circumstellar disk (Smith & Robinson 1999). We show here that the X-ray and optical emissions of the prototype of the class, Gamma-Cas, are very well correlated on year time scales with no significant time delay. Since the expected migration time from internal disk regions that emit most of the optical flux to the orbit of the companion star is of several years, the...

  13. Probing the hard and intermediate states of X-ray binaries using short time-scale variability

    Science.gov (United States)

    Skipper, Chris J.; McHardy, Ian M.

    2016-05-01

    Below an accretion rate of approximately a few per cent of the Eddington accretion rate, X-ray binary systems are not usually found in the soft spectral state. However, at accretion rates a factor of a few lower still, in the hard state, there is another spectral transition which is well observed but not well understood. Below {˜ }0.5-1 per cent of the Eddington accretion rate (dot{m}_crit), the spectral index hardens with increasing accretion rate, but above dot{m}_crit, although still in the hard state, the spectral index softens with increasing accretion rate. Here we use a combination of X-ray spectral fitting and a study of short time-scale spectral variability to examine the behaviour of three well-known X-ray binaries: Cygnus X-1, GX 339-4 and XTE J1118+480. In Cygnus X-1 we find separate hard and soft continuum components, and show using root mean square (rms) spectra that the soft component dominates the variability. The spectral transition at dot{m}_crit is clearly present in the hard-state hardness-intensity diagrams of Cygnus X-1. Above dot{m}_crit, GX 339-4 shows similar softer-when-brighter behaviour at both long and short time-scales. Similarly, XTE J1118+480, which remains well below dot{m}_crit, has harder-when-brighter behaviour on all time-scales. We interpret these results in terms of two continuum components: a hard power law which dominates the spectra when the accretion rate is low, probably arising from Comptonization of cyclo-synchrotron photons from the corona, and a soft power law which dominates at higher accretion rates, arising from Comptonization of seed photons from the accretion disc.

  14. Hard X-ray dose intensity and spatial distribution in a plasma focus device using thermoluminescence dosimeters

    Indian Academy of Sciences (India)

    A Kanani; M N Nasrabadi; B Shirani; I Jabbari

    2015-07-01

    In the present study, X-ray emission dose characteristics from a small Mather-type PF device in various pressures of argon as the operating gas were studied. The PF device was powered by a 12 F capacitor at 25 kV charging voltage. Time-integrated hard X-ray (HXR) emission was investigated using thermoluminescence dosimeters (TLDs). These detectors were calibrated with 60Co and 131Cs sources. Twenty-four dosimeters were placed at four different radial distances from the axis of the electrodes at the top of the anode to measure the dose spatial distribution at the top of the anode for different pressures (0.5–1.3 mbar). At each radius, six dosimeters were placed circularly with equal angular intervals on the inner surface of the device chamber. It was found that the optimum pressure for the highest yield of X-ray is 0.9 mbar. The maximum measured dose was 17 mGy per shot at the top of the anode and about 0.5 mGy per shot at 90° with respect to the anode axis. Furthermore, these results showed that the dose at each radius is symmetrical at 360° around the top of the anode, but X-ray distribution follows an anisotropical behaviour. A fast plastic scintillator was also used for time-resolved HXR detection, and a linear relation was observed between the amplitude of the scintillator-PMT signals and TLD responses.

  15. Hard X-ray Ptychography: Making It Cool, Colorful and Fast

    Science.gov (United States)

    Deng, Junjing

    Ptychography is a recently developed coherent imaging technique for extended objects, with a resolution not limited by the lens. Because X-rays have short wavelengths and high penetration ability, X-ray ptychography provides a powerful and unique tool for studying thick samples at high spatial resolution. We have advanced X-ray ptychography by making it cool, colorful, and fast. We make it cool by carrying out ptychography experiments at cryogenic conditions to image frozen-hydrated specimens. This largely removes the limitations of radiation damage on the achievable resolution, and allows one to obtain excellent preservation of structure and chemistry in biological specimens. We make it colorful by combining it with X-ray fluorescence measurements of chemical element distributions. In studies of biological specimens, this means that ptychography can reveal cellular ultrastructure at high contrast and at a resolution well beyond that of X-ray focusing optics, while X-ray fluorescence is used to simultaneously image the distribution of trace elements in cells (such as metals that play key roles in cell functions and which can be used in various disease therapeutic agents). Because X-ray fluorescence is not very sensitive for showing the light elements that comprise the majority of cellular materials, this combined approach provides the unique tool to obtain simultaneous views of ultrastructure and elemental compositions of specimens. We make it fast by using continuous-scan (or "fly-scan") methods. Conventional ptychography is implemented in a move-settle-measure approach, which is slow due to the positioning overheads. To overcome this bottleneck, we have developed fly-scan ptychography that is able to speed up the data collection, and real time on-site data analysis can be achieved by using a parallelized reconstruction code. With these advances, we conducted combined cryo X-ray ptychography and fluorescence imaging at 5.2 keV in a more practical way using fly

  16. Defect-Assisted Hard-X-Ray Microscopy with Capillary Optics.

    Science.gov (United States)

    Korecki, Paweł; Sowa, Katarzyna M; Jany, Benedykt R; Krok, Franciszek

    2016-06-10

    Polycapillary x-ray focusing devices are built from hundreds of thousands of bent microcapillaries that are stacked into hexagonal arrays. We show that intrinsic point defects of the optics (e.g., missing or larger capillaries) lead to the formation of multiple x-ray images of an object positioned in the focal plane. These images can be recorded in parallel, and can provide spatial resolution that is limited by the defect size and not by the focal spot size. In a proof-of-principle experiment, we demonstrate submicron resolution, which has not yet been achieved with polycapillary focusing optics. Tailored optics with a controlled distribution of "defects" could be used for multimodal nanoscale x-ray imaging with laboratory setups.

  17. A High Speed, Radiation Hard X-Ray Imaging Spectroscometer for Planetary Investigations

    Science.gov (United States)

    Kraft, R. P.; Kenter, A. T.; Murray, S. S.; Martindale, A.; Pearson, J.; Gladstone, R.; Branduardi-Raymont, G.; Elsner, R.; Kimura, T.; Ezoe, Y.; Grant, C.; Roediger, E.; Howell, R.; Elvis, M.; Smith, R.; Campbell, B.; Morgenthaler, J.; Kravens, T.; Steffl, A. J.; Hong, J.

    2014-01-01

    X-ray observations provide a unique window into fundamental processes in planetary physics, and one that is complementary to observations obtained at other wavelengths. We propose to develop an X-ray imaging spectrometer (0.1-10 keV band) that, on orbital planetary missions, would measure the elemental composition, density, and temperature of the hot plasma in gas giant magnetospheres, the interaction of the Solar wind with the upper atmospheres of terrestrial planets, and map the elemental composition of the surfaces of the Galilean moons and rocky or icy airless systems on spatial scales as small as a few meters. The X-ray emission from gas giants, terrestrial planets and moons with atmospheres, displays diverse characteristics that depend on the Solar wind's interaction with their upper atmospheres and/or magnetospheres. Our imaging spectrometer, as part of a dedicated mission to a gas giant, will be a paradigm changing technology. On a mission to the Jovian system, our baseline instrument would map the elemental composition of the rocky and icy surfaces of the Galilean moons via particle-induced X-ray fluorescence. This instrument would also measure the temperature, density and elemental abundance of the thermal plasma in the magnetosphere and in the Io plasma torus (IPT), explore the interaction of the Solar wind with the magnetosphere, and characterize the spectrum, flux, and temporal variability of X-ray emission from the polar auroras. We will constrain both the mode of energy transport and the effective transport coefficients in the IPT and throughout the Jovian magnetosphere by comparing temporal and spatial variations of the X-ray emitting plasma with those seen from the cooler but energetically dominant 5 eV plasma.

  18. Spatio-temporal Dynamics of Sources of Hard X-Ray Pulsations in Solar Flares

    Science.gov (United States)

    Kuznetsov, S. A.; Zimovets, I. V.; Morgachev, A. S.; Struminsky, A. B.

    2016-09-01

    We present a systematic analysis of the spatio-temporal evolution of sources of hard X-ray (HXR) pulsations in solar flares. We concentrate on disk flares whose impulsive phases are accompanied by a series of more than three successive peaks (pulsations) of HXR emission detected in the RHESSI 50 - 100 keV energy channel with a four-second time cadence. Twenty-nine such flares observed from February 2002 to June 2015 with characteristic time differences between successive peaks P ≈8 - 270 s are studied. The main observational result of the analysis is that sources of HXR pulsations in all flares are not stationary, they demonstrate apparent movements or displacements in the parent active regions from pulsation to pulsation. The flares can be subdivided into two main groups depending on the character of the dynamics of the HXR sources. Group 1 consists of 16 flares ( 55~%) that show systematic dynamics of the HXR sources from pulsation to pulsation with respect to a magnetic polarity inversion line (MPIL), which has a simple extended trace on the photosphere. Group 2 consists of 13 flares ( 45~%) that show more chaotic displacements of the HXR sources with respect to an MPIL with a more complex structure, and sometimes several MPILs are present in the parent active regions of such flares. Based on the observations, we conclude that the mechanism of the flare HXR pulsations (at least with time differences of the considered range) is related to successive triggering of the flare energy release process in different magnetic loops (or bundles of loops) of the parent active regions. Group 1 flare regions consist of loops stacked into magnetic arcades that are extended along MPILs. Group 2 flare regions have more complex magnetic structures, and the loops are arranged more chaotically and randomly there. We also found that at least 14 ( 88~%) group 1 flares and 11 ( 85~%) group 2 flares are accompanied by coronal mass ejections (CMEs), i.e. the absolute majority of the

  19. Simulation of Quiet-Sun Hard X-Rays Related to Solar Wind Superhalo Electrons

    Science.gov (United States)

    Wang, Wen; Wang, Linghua; Krucker, Säm; Hannah, Iain

    2016-05-01

    In this paper, we propose that the accelerated electrons in the quiet Sun could collide with the solar atmosphere to emit Hard X-rays (HXRs) via non-thermal bremsstrahlung, while some of these electrons would move upwards and escape into the interplanetary medium, to form a superhalo electron population measured in the solar wind. After considering the electron energy loss due to Coulomb collisions and the ambipolar electrostatic potential, we find that the sources of the superhalo could only occur high in the corona (at a heliocentric altitude ≳ 1.9 R_{⊙} (the mean radius of the Sun)), to remain a power-law shape of electron spectrum as observed by Solar Terrestrial Relations Observatory (STEREO) at 1 AU near solar minimum (Wang et al. in Astrophys. J. Lett. 753, L23, 2012). The modeled quiet-Sun HXRs related to the superhalo electrons fit well to a power-law spectrum, f ˜ ɛ^{-γ} in the photon energy ɛ, with an index γ≈2.0 - 2.3 (3.3 - 3.7) at 10 - 100 keV, for the warm/cold-thick-target (thin-target) emissions produced by the downward-traveling (upward-traveling) accelerated electrons. These simulated quiet-Sun spectra are significantly harder than the observed spectra of most solar HXR flares. Assuming that the quiet-Sun sources cover 5 % of the solar surface, the modeled thin-target HXRs are more than six orders of magnitude weaker than the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) upper limit for quiet-Sun HXRs (Hannah et al. in Astrophys. J. 724, 487, 2010). Using the thick-target model for the downward-traveling electrons, the RHESSI upper limit restricts the number of downward-traveling electrons to at most {≈} 3 times the number of escaping electrons. This ratio is fundamentally different from what is observed during solar flares associated with escaping electrons where the fraction of downward-traveling electrons dominates by a factor of 100 to 1000 over the escaping population.

  20. Exploring hardness enhancement in superhard tungsten tetraboride-based solid solutions using radial X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Miao; Turner, Christopher L. [Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095 (United States); Mohammadi, Reza [Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095 (United States); Department of Materials Science and Engineering, UCLA, Los Angeles, California 90095 (United States); Kaner, Richard B., E-mail: kaner@chem.ucla.edu, E-mail: akavner@ucla.edu, E-mail: tolbert@chem.ucla.edu; Tolbert, Sarah H., E-mail: kaner@chem.ucla.edu, E-mail: akavner@ucla.edu, E-mail: tolbert@chem.ucla.edu [Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095 (United States); Department of Materials Science and Engineering, UCLA, Los Angeles, California 90095 (United States); The California NanoSystems Institute (CNSI), UCLA, Los Angeles, California 90095 (United States); Kavner, Abby, E-mail: kaner@chem.ucla.edu, E-mail: akavner@ucla.edu, E-mail: tolbert@chem.ucla.edu [Department of Earth, Planetary, and Space Sciences, UCLA, Los Angeles, California 90095 (United States)

    2015-07-27

    In this work, we explore the hardening mechanisms in WB{sub 4}-based solid solutions upon addition of Ta, Mn, and Cr using in situ radial X-ray diffraction techniques under non-hydrostatic pressure. By examining the lattice-supported differential strain, we provide insights into the mechanism for hardness increase in binary solid solutions at low dopant concentrations. Speculations on the combined effects of electronic structure and atomic size in ternary WB{sub 4} solid solutions containing Ta with Mn or Cr are also included to understand the extremely high hardness of these materials.

  1. Exploring hardness enhancement in superhard tungsten tetraboride-based solid solutions using radial X-ray diffraction

    International Nuclear Information System (INIS)

    In this work, we explore the hardening mechanisms in WB4-based solid solutions upon addition of Ta, Mn, and Cr using in situ radial X-ray diffraction techniques under non-hydrostatic pressure. By examining the lattice-supported differential strain, we provide insights into the mechanism for hardness increase in binary solid solutions at low dopant concentrations. Speculations on the combined effects of electronic structure and atomic size in ternary WB4 solid solutions containing Ta with Mn or Cr are also included to understand the extremely high hardness of these materials

  2. Nanofocusing of hard X-ray free electron laser pulses using diamond based Fresnel zone plates

    OpenAIRE

    David, C.; Gorelick, S.; S. Rutishauser; Krzywinski, J.; Vila-Comamala, J.; Guzenko, V.A.; Bunk, O.; E. Färm; Ritala, M; Cammarata, M.; Fritz, D. M.; Barrett, R.; Samoylova, L.; Grünert, J.; Sinn, H.

    2011-01-01

    A growing number of X-ray sources based on the free-electron laser (XFEL) principle are presently under construction or have recently started operation. The intense, ultrashort pulses of these sources will enable new insights in many different fields of science. A key problem is to provide x-ray optical elements capable of collecting the largest possible fraction of the radiation and to focus into the smallest possible focus. As a key step towards this goal, we demonstrate here the first nano...

  3. 11 nm hard X-ray focus from a large-aperture multilayer Laue lens

    OpenAIRE

    Xiaojing Huang; Hanfei Yan; Evgeny Nazaretski; Raymond Conley; Nathalie Bouet; Juan Zhou; Kenneth Lauer; Li Li; Daejin Eom; Daniel Legnini; Ross Harder; Robinson, Ian K.; Chu, Yong S.

    2013-01-01

    The focusing performance of a multilayer Laue lens (MLL) with 43.4 μm aperture, 4 nm finest zone width and 4.2 mm focal length at 12 keV was characterized with X-rays using ptychography method. The reconstructed probe shows a full-width-at-half-maximum (FWHM) peak size of 11.2 nm. The obtained X-ray wavefront shows excellent agreement with the dynamical calculations, exhibiting aberrations less than 0.3 wave period, which ensures the MLL capable of producing a diffraction-limited focus while ...

  4. Micro-structural characterization of materials using synchrotron hard X-ray imaging techniques

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Ashish, E-mail: neoashu@hotmail.com; Singh, Balwant; Kashyap, Yogesh; Sarkar, P. S.; Shukla, Mayank; Sinha, Amar [Neutron and X-ray Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2015-06-24

    X-ray imaging has been an important tool to study the materials microstructure with the laboratory based sources however the advent of third generation synchrotron sources has introduced new concepts in X-ray imaging such as phase contrast imaging, micro-tomography, fluorescence imaging and diffraction enhance imaging. These techniques are being used to provide information of materials about their density distribution, porosity, geometrical and morphological characteristics at sub-micron scalewith improved contrast. This paper discusses the development of various imaging techniques at synchrotron based imaging beamline Indus-2 and few recent experiments carried out at this facility.

  5. Extended Hard-X-Ray Emission in the Inner Few Parsecs of the Galaxy

    Science.gov (United States)

    Perez, Kerstin; Hailey, Charles J.; Bauer, Franz E.; Krivonos, Roman A.; Mori, Kaya; Baganoff, Frederick K.; Barriere, Nicholas M.; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Grefenstette, Brian W.; Grindlay, Jonathan E.; Harrison, Fiona A.; Hong, Jaesub; Madsen, Kristin K.; Nynka, Melania; Stern, Daniel; Tomsick, John A.; Wik, Daniel R.; Zhang, Shuo; Zhang, William W.; Zoglauer, Andreas

    2015-01-01

    The Galactic Centre hosts a puzzling stellar population in its inner few parsecs, with a high abundance of surprisingly young, relatively massive stars bound within the deep potential well of the central supermassive black hole, Sagittarius A* (ref. 1). Previous studies suggest that the population of objects emitting soft X-rays (less than 10 kiloelectronvolts) within the surrounding hundreds of parsecs, as well as the population responsible for unresolved X-ray emission extending along the Galactic plane, is dominated by accreting white dwarf systems2, 3, 4, 5.

  6. Coherent hard x-rays from attosecond pulse train-assisted harmonic generation

    OpenAIRE

    Klaiber, Michael; Hatsagortsyan, Karen Z.; Müller, Carsten; Christoph H. Keitel

    2007-01-01

    High-order harmonic generation from atomic systems is considered in the crossed fields of a relativistically strong infrared laser and a weak attosecond-pulse train of soft x-rays. Due to one-photon ionization by the x-ray pulse, the ionized electron obtains a starting momentum that compensates the relativistic drift which is induced by the laser magnetic field, and allows the electron to efficiently emit harmonic radiation upon recombination with the atomic core in the relativistic regime. I...

  7. The Si/CdTe semiconductor camera of the ASTRO-H Hard X-ray Imager (HXI)

    Science.gov (United States)

    Sato, Goro; Hagino, Kouichi; Watanabe, Shin; Genba, Kei; Harayama, Atsushi; Kanematsu, Hironori; Kataoka, Jun; Katsuragawa, Miho; Kawaharada, Madoka; Kobayashi, Shogo; Kokubun, Motohide; Kuroda, Yoshikatsu; Makishima, Kazuo; Masukawa, Kazunori; Mimura, Taketo; Miyake, Katsuma; Murakami, Hiroaki; Nakano, Toshio; Nakazawa, Kazuhiro; Noda, Hirofumi; Odaka, Hirokazu; Onishi, Mitsunobu; Saito, Shinya; Sato, Rie; Sato, Tamotsu; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shin`ichiro; Yuasa, Takayuki

    2016-09-01

    The Hard X-ray Imager (HXI) is one of the instruments onboard the ASTRO-H mission [1-4] to be launched in early 2016. The HXI is the focal plane detector of the hard X-ray reflecting telescope that covers an energy range from 5 to 80 keV. It will execute observations of astronomical objects with a sensitivity for point sources as faint as 1/100,000 of the Crab nebula at > 10 keV. The HXI camera - the imaging part of the HXI - is realized by a hybrid semiconductor detector system that consists of silicon (Si) and cadmium telluride (CdTe) semiconductor detectors. Here, we present the final design of the HXI camera and report on the development of the flight model. The camera is composed of four layers of Double-sided Silicon Strip Detectors (DSSDs) and one layer of CdTe Double-sided Strip Detector (CdTe-DSD), each with an imaging area of 32 mm×32 mm. The strip pitch of the Si and CdTe sensors is 250 μm, and the signals from all 1280 strips are processed by 40 Application Specified Integrated Circuits (ASICs) developed for the HXI. The five layers of sensors are vertically stacked with a 4 mm spacing to increase the detection efficiency. The thickness of the sensors is 0.5 mm for the Si, and 0.75 mm for the CdTe. In this configuration, soft X-ray photons will be absorbed in the Si part, while hard X-ray photons will go through the Si part and will be detected in the CdTe part. The design of the sensor trays, peripheral circuits, power connections, and readout schemes are also described. The flight models of the HXI camera have been manufactured, tested and installed in the HXI instrument and then on the satellite.

  8. Pointing System for the Balloon-Borne Astronomical Payloads

    CERN Document Server

    Nirmal, K; Mathew, Joice; Sarpotdar, Mayuresh; Suresh, Ambily; Prakash, Ajin; Safonova, Margarita; Murthy, Jayant

    2016-01-01

    We describe the development and implementation of a light-weight, fully autonomous 2-axis pointing and stabilization system designed for balloon-borne astronomical payloads. The system is developed using off-the-shelf components such as Arduino Uno controller, HMC 5883L magnetometer, MPU-9150 Inertial Measurement Unit (IMU) and iWave GPS receiver unit. It is a compact and rugged system which can also be used to take images/video in a moving vehicle, or in areal photography. The system performance is evaluated from the ground, as well as in conditions simulated to imitate the actual flight by using a tethered launch.

  9. Balloon-Borne System Would Aim Instrument Toward Sun

    Science.gov (United States)

    Polites, M. E.

    1992-01-01

    Proposed system including digital control computer, control sensors, and control actuators aims telescope or other balloon-borne instrument toward Sun. Pointing system and instrument flown on gondola, suspended from balloon. System includes reaction wheel, which applies azimuthal control torques to gondola, and torque motor to apply low-frequency azimuthal torques between gondola and cable. Three single-axis rate gyroscopes measure yaw, pitch, and roll. Inclinometer measures roll angle. Two-axis Sun sensor measures deviation, in yaw and pitch, of attitude of instrument from line to apparent center of Sun. System provides initial coarse pointing, then maintains fine pointing.

  10. Trends in hard X-ray fluorescence mapping: environmental applications in the age of fast detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lombi, E.; Donner, E. [University of South Australia, Centre for Environmental Risk Assessment and Remediation, Mawson Lakes, South Australia (Australia); CRC CARE, PO Box 486, Salisbury, South Australia (Australia); Jonge, M.D. de; Paterson, D. [Australian Synchrotron, X-ray Fluorescence Microscopy, 800 Blackburn Road, Clayton, Victoria (Australia); Ryan, C.G. [CSIRO Earth Science and Resource Engineering, Normanby Road, Clayton, Victoria (Australia)

    2011-06-15

    Environmental samples are extremely diverse but share a tendency for heterogeneity and complexity. This heterogeneity poses methodological challenges when investigating biogeochemical processes. In recent years, the development of analytical tools capable of probing element distribution and speciation at the microscale have allowed this challenge to be addressed. Of these available tools, laterally resolved synchrotron techniques such as X-ray fluorescence mapping are key methods for the in situ investigation of micronutrients and inorganic contaminants in environmental samples. This article demonstrates how recent advances in X-ray fluorescence detector technology are bringing new possibilities to environmental research. Fast detectors are helping to circumvent major issues such as X-ray beam damage of hydrated samples, as dwell times during scanning are reduced. They are also helping to reduce temporal beamtime requirements, making particularly time-consuming techniques such as micro X-ray fluorescence ({mu}XRF) tomography increasingly feasible. This article focuses on {mu}XRF mapping of nutrients and metalloids in environmental samples, and suggests that the current divide between mapping and speciation techniques will be increasingly blurred by the development of combined approaches. (orig.)

  11. Wavefront metrology for coherent hard X-rays by scanning a microsphere.

    Science.gov (United States)

    Skjønsfjell, Eirik Torbjørn Bakken; Chushkin, Yuriy; Zontone, Federico; Patil, Nilesh; Gibaud, Alain; Breiby, Dag W

    2016-05-16

    Characterization of the wavefront of an X-ray beam is of primary importance for all applications where coherence plays a major role. Imaging techniques based on numerically retrieving the phase from interference patterns are often relying on an a-priori assumption of the wavefront shape. In Coherent X-ray Diffraction Imaging (CXDI) a planar incoming wave field is often assumed for the inversion of the measured diffraction pattern, which allows retrieving the real space image via simple Fourier transformation. It is therefore important to know how reliable the plane wave approximation is to describe the real wavefront. Here, we demonstrate that the quantitative wavefront shape and flux distribution of an X-ray beam used for CXDI can be measured by using a micrometer size metal-coated polymer sphere serving in a similar way as the hole array in a Hartmann wavefront sensor. The method relies on monitoring the shape and center of the scattered intensity distribution in the far field using a 2D area detector while raster-scanning the microsphere with respect to the incoming beam. The reconstructed X-ray wavefront was found to have a well-defined central region of approximately 16 µm diameter and a weaker, asymmetric, intensity distribution extending 30 µm from the beam center. The phase front distortion was primarily spherical with an effective radius of 0.55 m which matches the distance to the last upstream beam-defining slit, and could be accurately represented by Zernike polynomials. PMID:27409892

  12. New developments for the investigation of hard X-rays emitted by peeling adhesive tapes.

    Science.gov (United States)

    Krämer, D; Lützenkirchen-Hecht, D; Lühmann, B; Keite-Telgenbüscher, K; Frahm, R

    2013-05-01

    We realized an advanced apparatus for the investigation of emitted X-rays produced by peeling adhesive tape rolls under vacuum conditions. Two stepper motors can unwind and rewind a tape roll, and an additional roller with an optical encoder provides measurement and control of the tape speed. This way reproducible and consecutive experiments are feasible without having to change the tape or break the vacuum. The dependence of the X-ray emission on tape speed, gas pressure, type of adhesive tape, and detector angle has been investigated. The resulting spectra are continuous and span an X-ray energy range of typically 2-60 keV with high intensity. Furthermore, the new apparatus allows the in situ metalization of adhesive tape rolls by a gold sputter source. A significantly increased X-ray emission was observed for adhesive tapes with a metal coating. Thin metal foils have been placed between the tape and the detector, different K- and L-absorption edges could be measured. A considerable enhancement of the emission was achieved under the influence of the magnetic field of an NdFeB permanent magnet. PMID:23742586

  13. Hard X-ray luminosity function of tidal disruption events: First results from the MAXI extragalactic survey

    Science.gov (United States)

    Kawamuro, Taiki; Ueda, Yoshihiro; Shidatsu, Megumi; Hori, Takafumi; Kawai, Nobuyuki; Negoro, Hitoshi; Mihara, Tatehiro

    2016-08-01

    We derive the first hard X-ray luminosity function (XLF) of stellar tidal disruption events (TDEs) by supermassive black holes (SMBHs), which gives an occurrence rate of TDEs per unit volume as a function of peak luminosity and redshift, utilizing an unbiased sample observed by the Monitor of All-sky X-ray Image (MAXI). On the basis of the light curves characterized by a power-law decay with an index of -5/3, a systematic search using the MAXI data detected four TDEs in the first 37 months of observations, all of which have been found in the literature. To formulate the TDE XLF, we consider the mass function of SMBHs, that of disrupted stars, the specific TDE rate as a function of SMBH mass, and the fraction of TDEs with relativistic jets. We perform an unbinned maximum likelihood fit to the MAXI TDE list and check the consistency with the observed TDE rate in the ROSAT all-sky survey. The results suggest that the intrinsic fraction of the jet-accompanying events is 0.0007%-34%. We confirm that at z ≲ 1.5 the contamination of the hard X-ray luminosity functions of active galactic nuclei by TDEs is not significant and hence that their contribution to the growth of SMBHs is negligible at the redshifts.

  14. Hard X-ray Emission from Sh2-104: A NuSTAR search for Gamma-ray Counterparts

    CERN Document Server

    Gotthelf, E V; Aliu, E; Paredes, J M; Tomsick, J A; Boggs, S E; Christensen, F E; Craig, W W; Hailey, C J; Harrison, F A; Hong, J S; Rahoui, F; Stern, D; Zhang, W W

    2016-01-01

    We present NuSTAR hard X-ray observations of Sh 2-104, a compact HII region containing several young massive stellar clusters (YMSCs). We have detected distinct hard X-ray sources coincident with localized VERITAS TeV emission recently resolved from the giant gamma-ray complex MGRO J2019+37 in the Cygnus region. Faint, diffuse X-ray emission coincident with the eastern YMSC in Sh2-104 is likely the result of colliding winds of component stars. Just outside the radio shell of Sh 2-104 lies 3XMM J201744.7+365045 and a nearby nebula NuSTAR J201744.3+364812, whose properties are most consistent with extragalactic objects. The combined XMM-Newton and NuSTAR spectrum of 3XMM J201744.7+365045 is well-fit to an absorbed power-law model with NH = (3.1 +/- 1.0)E22 cm^-2 and photon index Gamma = 2.1 +/- 0.1. Based on possible long-term flux variation and the lack of detected pulsations (< 43% modulation), this object is likely a background AGN rather than a Galactic pulsar. The spectrum of the NuSTAR nebula shows evi...

  15. SU Lyncis, a hard X-ray bright M giant: Clues point to a large hidden population of symbiotic stars

    CERN Document Server

    Mukai, K; Cusumano, G; Segreto, A; Munari, U; Sokoloski, J L; Lucy, A B; Nelson, T; Nunez, N E

    2016-01-01

    Symbiotic star surveys have traditionally relied almost exclusively on low resolution optical spectroscopy. However, we can obtain a more reliable estimate of their total Galactic population by using all available signatures of the symbiotic phenomenon. Here we report the discovery of a hard X-ray source, 4PBC J0642.9+5528, in the Swift hard X-ray all-sky survey, and identify it with a poorly studied red giant, SU Lyn, using pointed Swift observations and ground-based optical spectroscopy. The X-ray spectrum, the optical to UV spectrum, and the rapid UV variability of SU Lyn are all consistent with our interpretation that it is a symbiotic star containing an accreting white dwarf. The symbiotic nature of SU Lyn went unnoticed until now, because it does not exhibit emission lines strong enough to be obvious in low resolution spectra. We argue that symbiotic stars without shell-burning have weak emission lines, and that the current lists of symbiotic stars are biased in favor of shell-burning systems. We conclu...

  16. SU Lyncis, a hard X-ray bright M giant: clues point to a large hidden population of symbiotic stars

    Science.gov (United States)

    Mukai, K.; Luna, G. J. M.; Cusumano, G.; Segreto, A.; Munari, U.; Sokoloski, J. L.; Lucy, A. B.; Nelson, T.; Nuñez, N. E.

    2016-09-01

    Symbiotic star surveys have traditionally relied almost exclusively on low resolution optical spectroscopy. However, we can obtain a more reliable estimate of their total Galactic population by using all available signatures of the symbiotic phenomenon. Here we report the discovery of a hard X-ray source, 4PBC J0642.9+5528, in the Swift hard X-ray all-sky survey, and identify it with a poorly studied red giant, SU Lyn, using pointed Swift observations and ground-based optical spectroscopy. The X-ray spectrum, the optical to UV spectrum, and the rapid UV variability of SU Lyn are all consistent with our interpretation that it is a symbiotic star containing an accreting white dwarf. The symbiotic nature of SU Lyn went unnoticed until now, because it does not exhibit emission lines strong enough to be obvious in low resolution spectra. We argue that symbiotic stars without shell-burning have weak emission lines, and that the current lists of symbiotic stars are biased in favour of shell-burning systems. We conclude that the true population of symbiotic stars has been underestimated, potentially by a large factor.

  17. NuSTAR detection of 4s Hard X-ray Lags from the Accreting Pulsar GS 0834-430

    Directory of Open Access Journals (Sweden)

    Bachetti Matteo

    2014-01-01

    Full Text Available The NuSTAR hard X-ray telescope observed the transient Be/X-ray binary GS 0834–430 during its 2012 outburst. The source is detected between 3 – 79 keV with high statistical significance, and we were able to perform very accurate spectral and timing analysis. The phase-averaged spectrum is consistent with that observed in many other magnetized accreting pulsars. We fail to detect cyclotron resonance scattering features in either phase-averaged nor phase-resolved spectra that would allow us to constrain the pulsar’s magnetic field. We detect a pulse period of ~ 12:29 s in all energy bands. The pulse profile can be modeled with a double Gaussian and shows a strong and smooth hard lag of up to 0.3 cycles in phase, or about 4s between the pulse at ~ 3 and ≳ 30 keV. This is the first report of such a strong lag in high-mass X-ray binary (HMXB pulsars. Previously reported lags have been significantly smaller in phase and restricted to low-energies (E<10 keV. We investigate the possible mechanisms that might produce such lags. We find the most likely explanation for this effect to be a complex beam geometry.

  18. Optical Spectroscopic Follow-up Of Hard X-ray Sources In The Xmm-slew Survey

    Science.gov (United States)

    Lewis, Karen T.; Buckingham, S.; Mushotzky, R. F.

    2007-12-01

    The XMM Slew Survey is projected to cover 80% of the sky in the soft (0.5--2 keV) and hard (2--10 keV) bands. The survey has a flux limit of 4 × 10-12 erg s-1 cm-2 in the hard band. Like all hard-band surveys, it has the ability to detect even heavily absorbed AGN, and the large area coverage makes it possible to detect rare and/or luminous AGN. Thus the XMM Slew Survey offers a rare opportunity to obtain an accurate "census" of the z\\ 0.1-0.2 AGN population which has not been well probed by previous, less-sensitive hard-band all sky surveys or deep "pencil beam" surveys. Over the past year, we have used the 4m Mayall and Blanco telescopes to obtain optical spectra of all the optical sources within the error circle of the un-identified X-ray sources in the 1st release of the XMM Sleww Survey. Approximately 2/3 of the sources have been robustly identified as AGN with an average redshift of 0.15. The precise classification of the remaining sources is unknown as follow-up observations with Swift XRT revealed that some sources were transient and most likely stellar in nature. In other cases, the more accurate position provided by Swift made it clear that none of the observed sources was the counterpart, implying that the counterpart has an r-band magnitude of greater than 20 which is unexpected for a source with such a large X-ray flux. The overwhelming majority of the AGN exhibit broad optical emission lines. This is very surprising because the X-ray properties suggested that many of these sources were heavily absorbed. Here we present our preliminary results and motivate the need for dedicated X-ray observations ( 5 ks) of this sample to help unravel the apparent discrepancy between the optical and X-ray properties of these sources.

  19. Evidence for a change in the X-ray radiation mechanism in the hard state of Galactic black holes

    CERN Document Server

    Sobolewska, M A; Done, C; Malzac, J

    2011-01-01

    We present results on spectral variability of two Galactic black hole X-ray binaries, GRO J1655-40 and GX 339-4, in the hard state. We confirm a transition in behaviour of the photon index with luminosity, such that the well known decrease in X-ray photon index with decreasing luminosity only continues down to L_bol ~ 0.01 L_Edd . Below this point the photon index increases again. For Comptonisation models, this implies that the ratio of the Compton luminosity to seed photon luminosity, lh/ls, changes with bolometric luminosity, consistent with a scenario where seed photons change from cyclo-synchrotron at the lowest luminosities to those from a truncated disc. Alternatively, the transition could mark the point below which the non-thermal jet starts to dominate, or where reprocessed photons replace the viscous ones in an outflowing corona model.

  20. Laser-wakefield accelerators as hard x-ray sources for 3D medical imaging of human bone.

    Science.gov (United States)

    Cole, J M; Wood, J C; Lopes, N C; Poder, K; Abel, R L; Alatabi, S; Bryant, J S J; Jin, A; Kneip, S; Mecseki, K; Symes, D R; Mangles, S P D; Najmudin, Z

    2015-01-01

    A bright μm-sized source of hard synchrotron x-rays (critical energy Ecrit > 30 keV) based on the betatron oscillations of laser wakefield accelerated electrons has been developed. The potential of this source for medical imaging was demonstrated by performing micro-computed tomography of a human femoral trabecular bone sample, allowing full 3D reconstruction to a resolution below 50 μm. The use of a 1 cm long wakefield accelerator means that the length of the beamline (excluding the laser) is dominated by the x-ray imaging distances rather than the electron acceleration distances. The source possesses high peak brightness, which allows each image to be recorded with a single exposure and reduces the time required for a full tomographic scan. These properties make this an interesting laboratory source for many tomographic imaging applications. PMID:26283308