Narrow-line Seyfert 1 galaxies at hard X-rays

NASA Astrophysics Data System (ADS)

Panessa, F.; de Rosa, A.; Bassani, L.; Bazzano, A.; Bird, A.; Landi, R.; Malizia, A.; Miniutti, G.; Molina, M.; Ubertini, P.

2011-11-01

Narrow-line Seyfert 1 (NLSy1) galaxies are a peculiar class of type 1 active galactic nuclei (broad-line Seyfert 1 galaxies, hereinafter BLSy1). The X-ray properties of individual objects belonging to this class are often extreme and associated with accretion at high Eddington ratios. Here, we present a study on a sample of 14 NLSy1 galaxies selected at hard X-rays (>20 keV) from the fourth INTEGRAL/IBIS catalogue. The 20-100 keV IBIS spectra show hard-X-ray photon indices flatly distributed (Γ20-100 keV ranging from ˜1.3 to ˜3.6) with an average value of <Γ20-100 keV>= 2.3 ± 0.7, compatible with a sample of hard-X-ray BLSy1 average slopes. Instead, NLSy1 galaxies show steeper spectral indices with respect to BLSy1 galaxies when broad-band spectra are considered. Indeed, we combine XMM-Newton and Swift/XRT with INTEGRAL/IBIS data sets to obtain a wide energy spectral coverage (0.3-100 keV). A constraint on the high energy cut-off and on the reflection component is achieved only in one source, SWIFT J2127.4+5654 (Ecut-off˜ 50 keV, R= 1.0+0.5- 0.4). Hard-X-ray-selected NLSy1 galaxies do not display particularly strong soft excess emission, while absorption fully or partially covering the continuum is often measured as well as Fe line emission features. Variability is a common trait in this sample, both at X-rays and at hard X-rays. The fraction of NLSy1 galaxies in the hard-X-ray sky is likely to be ˜15 per cent, in agreement with estimates derived in optically selected NLSy1 samples. We confirm the association of NLSy1 galaxies with small black hole masses with a peak at 107 M⊙ in the distribution; however, hard-X-ray NLSy1 galaxies seem to occupy the lower tail of the Eddington ratio distribution of classical NLSy1 galaxies. Based on observations obtained with the INTEGRAL/IBIS, XMM-Newton and Swift/XRT.

A Multiwavelength Study of Cygnus X-3

NASA Technical Reports Server (NTRS)

McCollough, M. L; Robinson, C. R.; Zhang, S. N.; Paciesas, W. S.; Harmon, B. A.; Hjellming, R. M.; Rupen, M.; Waltman, E. B.; Foster, R. S.; Ghigo, F. D.

1997-01-01

We present a global comparison of long term observations of the hard X-ray (20-100 keV), soft X-ray (1.5-12 keV), infrared (1-2 micron) and radio (2.25, 8.3 and 15 GHz) bands for the unusual X-ray binary Cygnus X-3. Data were obtained in the hard X-ray band from CGRO/BATSE, in the soft X-ray band from Rossi Xray Timing Explorer (RXTE)/ASM, in the radio band from the Green Bank Interferometer and Ryle Telescope and in the infrared band from various ground based observatories. Radio flares, quenched radio states and quiescent radio emission can all be associated with changes in the hard and soft X-ray intensity. The injection of plasma into the radio jet is directly related to changes in the hard and soft X-ray emission. The infrared observations are examined in the context of these findings.

Final Report on X-ray Yields from OMEGA II Targets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fournier, K B; May, M J; MacLaren, S A

2007-06-20

We present details about X-ray yields measured with Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories (SNL) diagnostics in soft and moderately hard X-ray bands from laser-driven, doped-aerogel targets shot on 07/14/06 during the OMEGA II test series. Yields accurate to {+-}25% in the 5-15 keV band are measured with Livermore's HENWAY spectrometer. Yields in the sub-keV to 3.2 keV band are measured with LLNL's DANTE diagnostic, the DANTE yields are accurate to 10-15%. SNL ran a PCD-based diagnostic that also measured X-ray yields in the spectral region above 4 keV, and also down to the sub-keV range. Themore » PCD and HENWAY and DANTE numbers are compared. The time histories of the moderately hard (h{nu} > 4 keV) X-ray signals are measured with LLNL's H11 PCD, and from two SNL PCDs with comparable filtration. There is general agreement between the H11 PCD and SNL PCD measured FWHM except for two of the shorter-laser-pulse shots, which is shown not to be due to analysis techniques. The recommended X-ray waveform is that from the SNL PCD p66k10, which was recorded on a fast, high-bandwidth TDS 6804 oscilloscope. X-ray waveforms from target emission in two softer spectral bands are also shown; the X-ray emissions have increasing duration as the spectral content gets softer.« less

Full-field x-ray nano-imaging at SSRF

NASA Astrophysics Data System (ADS)

Deng, Biao; Ren, Yuqi; Wang, Yudan; Du, Guohao; Xie, Honglan; Xiao, Tiqiao

2013-09-01

Full field X-ray nano-imaging focusing on material science is under developing at SSRF. A dedicated full field X-ray nano-imaging beamline based on bending magnet will be built in the SSRF phase-II project. The beamline aims at the 3D imaging of the nano-scale inner structures. The photon energy range is of 5-14keV. The design goals with the field of view (FOV) of 20μm and a spatial resolution of 20nm are proposed at 8 keV, taking a Fresnel zone plate (FZP) with outermost zone width of 25 nm. Futhermore, an X-ray nano-imaging microscope is under developing at the SSRF BL13W beamline, in which a larger FOV will be emphasized. This microscope is based on a beam shaper and a zone plate using both absorption contrast and Zernike phase contrast, with the optimized energy set to 10keV. The detailed design and the progress of the project will be introduced.

Optimization of niobium tunnel junctions as X-ray detectors

NASA Technical Reports Server (NTRS)

Saulnier, Gregory G.; Zacher, Robert A.; Van Vechten, Deborah; Boyer, Craig; Lovellette, Michael N.; Fritz, Gilbert G.; Soulen, Robert J.; Kang, Joonhee; Blamire, Mark; Kirk, Eugenie C. G.

1992-01-01

We report on our ongoing work using Nb/Al/AlO(x)/Nb junctions for the detection of X-rays. Detectors based on superconducting tunneling junctions offer the prospect of resolution over an order of magnitude higher than is obtainable with the current generation of semiconductor-based detectors. Results of measurements taken at 1.85 K (a temperature achievable with current space flight technology) include the current-voltage (I-V) curve, subgap current vs temperature, the dependence of the superconducting current on the applied magnetic field (Fraunhofer pattern), X-ray pulses, and the spectra from a 6 keV X-ray source which gave an intrinsic device resolution of approximately 700 eV. The collection of more than 10 exp 5 electrons per 6 keV photon is established.

The NuSTAR Serendipitous Survey: Hunting for the Most Extreme Obscured AGN at >10 keV

NASA Astrophysics Data System (ADS)

Lansbury, G. B.; Alexander, D. M.; Aird, J.; Gandhi, P.; Stern, D.; Koss, M.; Lamperti, I.; Ajello, M.; Annuar, A.; Assef, R. J.; Ballantyne, D. R.; Baloković, M.; Bauer, F. E.; Brandt, W. N.; Brightman, M.; Chen, C.-T. J.; Civano, F.; Comastri, A.; Del Moro, A.; Fuentes, C.; Harrison, F. A.; Marchesi, S.; Masini, A.; Mullaney, J. R.; Ricci, C.; Saez, C.; Tomsick, J. A.; Treister, E.; Walton, D. J.; Zappacosta, L.

2017-09-01

We identify sources with extremely hard X-ray spectra (I.e., with photon indices of {{Γ }}≲ 0.6) in the 13 deg2 NuSTAR serendipitous survey, to search for the most highly obscured active galactic nuclei (AGNs) detected at > 10 {keV}. Eight extreme NuSTAR sources are identified, and we use the NuSTAR data in combination with lower-energy X-ray observations (from Chandra, Swift XRT, and XMM-Newton) to characterize the broadband (0.5-24 keV) X-ray spectra. We find that all of the extreme sources are highly obscured AGNs, including three robust Compton-thick (CT; {N}{{H}}> 1.5× {10}24 cm-2) AGNs at low redshift (z< 0.1) and a likely CT AGN at higher redshift (z = 0.16). Most of the extreme sources would not have been identified as highly obscured based on the low-energy (< 10 keV) X-ray coverage alone. The multiwavelength properties (e.g., optical spectra and X-ray-mid-IR luminosity ratios) provide further support for the eight sources being significantly obscured. Correcting for absorption, the intrinsic rest-frame 10-40 keV luminosities of the extreme sources cover a broad range, from ≈ 5× {10}42 to 1045 erg s-1. The estimated number counts of CT AGNs in the NuSTAR serendipitous survey are in broad agreement with model expectations based on previous X-ray surveys, except for the lowest redshifts (z< 0.07), where we measure a high CT fraction of {f}{CT}{obs}={30}-12+16 % . For the small sample of CT AGNs, we find a high fraction of galaxy major mergers (50% ± 33%) compared to control samples of “normal” AGNs.

Applications of “Tender” Energy (1-5 keV) X-ray Absorption Spectroscopy in Life Sciences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Northrup, Paul; Leri, Alessandra; Tappero, Ryan

The “tender” energy range of 1 to 5 keV, between the energy ranges of most “hard” (>5 keV) and “soft” (<1 keV) synchrotron X-ray facilities, offers some unique opportunities for synchrotron-based X-ray absorption fine structure spectroscopy in life sciences. In particular the K absorption edges of Na through Ca offer opportunities to study local structure, speciation, and chemistry of many important biological compounds, structures and processes. This is an area of largely untapped science, in part due to a scarcity of optimized facilities. Such measurements also entail unique experimental challenges. Lastly, this brief review describes the technique, its experimental challenges,more » recent progress in development of microbeam measurement capabilities, and several highlights illustrating applications in life sciences.« less

Applications of “Tender” Energy (1-5 keV) X-ray Absorption Spectroscopy in Life Sciences

DOE PAGES

Northrup, Paul; Leri, Alessandra; Tappero, Ryan

2016-02-15

The “tender” energy range of 1 to 5 keV, between the energy ranges of most “hard” (>5 keV) and “soft” (<1 keV) synchrotron X-ray facilities, offers some unique opportunities for synchrotron-based X-ray absorption fine structure spectroscopy in life sciences. In particular the K absorption edges of Na through Ca offer opportunities to study local structure, speciation, and chemistry of many important biological compounds, structures and processes. This is an area of largely untapped science, in part due to a scarcity of optimized facilities. Such measurements also entail unique experimental challenges. Lastly, this brief review describes the technique, its experimental challenges,more » recent progress in development of microbeam measurement capabilities, and several highlights illustrating applications in life sciences.« less

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

NASA Astrophysics Data System (ADS)

Mori, Kaya; Hailey, Charles J.; 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; Barrière, 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

2015-12-01

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 (˜1023 cm-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 LX ≳ 1038 erg s-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 MWD ˜ 0.9 M⊙. 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.

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

THz-pump and X-ray-probe sources based on an electron linac

NASA Astrophysics Data System (ADS)

Setiniyaz, Sadiq; Park, Seong Hee; Kim, Hyun Woo; Vinokurov, Nikolay A.; Jang, Kyu-Ha; Lee, Kitae; Baek, In Hyung; Jeong, Young Uk

2017-11-01

We describe a compact THz-pump and X-ray-probe beamline, based on an electron linac, for ultrafast time-resolved diffraction applications. Two high-energy electron (γ > 50) bunches, 5 ns apart, impinge upon a single-foil or multifoil radiator and generate THz radiation and X-rays simultaneously. The THz pulse from the first bunch is synchronized to the X-ray beam of the second bunch by using an adjustable optical delay of a THz pulse. The peak power of THz radiation from the multifoil radiator is estimated to be 0.14 GW for a 200 pC well-optimized electron bunch. GEANT4 simulations show that a carbon foil with a thickness of 0.5-1.0 mm has the highest yield of 10-20 keV hard X-rays for a 25 MeV beam, which is approximately 103 photons/(keV pC-electrons) within a few degrees of the polar angle. A carbon multifoil radiator with 35 foils (25 μm thick each) can generate close to 103 hard X-rays/(keV pC-electrons) within a 2° acceptance angle. With 200 pC charge and a 100 Hz repetition rate, we can generate 107 X-rays per 1 keV energy bin per second or 105 X-rays per 1 keV energy bin per pulse. The longitudinal time profile of an X-ray pulse ranges from 400 to 600 fs depending on the acceptance angle. The broadening of the time duration of an X-ray pulse is observed owing to its diverging effect. A double-crystal monochromator will be used to select and transport the desired X-rays to the sample. The heating of the radiators by an electron beam is negligible because of the low beam current.

Sub-arcsec X-Ray Telescope for Imaging The Solar Corona In the 0.25 - 1.2 keV Band

NASA Technical Reports Server (NTRS)

Gallagher, Dennis; Cash, Webster; Jelsma, Schuyler; Farmer, Jason

1996-01-01

We have developed an X-ray telescope that uses a new technique for focusing X-rays with grazing incidence optics. The telescope was built with spherical optics for all of its components, utilizing the high quality surfaces obtainable when polishing spherical (as opposed to aspherical) optics. We tested the prototype X-ray telescope in the 300 meter vacuum pipe at White Sands Missile Range, NM. The telescope features 2 degee graze angles with tungsten coatings, yielding a bandpass of 0.25-1.5 keV with a peak effective area of 0.8 sq cm at 0.83 keV. Results from X-ray testing at energies of 0.25 keV and 0.93 keV (C-K and Cu-L) verify 0.5 arcsecond performance at 0.93 keV. Results from modeling the X-ray telescope's response to the Sun show that the current design would be capable of recording 10 half arcsecond images of a solar active region during a 300 second NASA sounding rocket flight.

Design of T-GEM detectors for X-ray diagnostics on JET

NASA Astrophysics Data System (ADS)

Rzadkiewicz, J.; Dominik, W.; Scholz, M.; Chernyshova, M.; Czarski, T.; Czyrkowski, H.; Dabrowski, R.; Jakubowska, K.; Karpinski, L.; Kasprowicz, G.; Kierzkowski, K.; Pozniak, K.; Salapa, Z.; Zabolotny, W.; Blanchard, P.; Tyrrell, S.; Zastrow, K.-D.; JET EFDA Contributors

2013-08-01

Upgraded high-resolution X-ray diagnostics on JET is expected to monitor the plasma radiation emitted by W46+ and Ni26+ ions at 2.4 keV and 7.8 keV photon energies, respectively. Both X-ray lines will be monitored by new generation energy-resolved micropattern gas detectors with 1-D position reconstruction capability. The detection structure is based on triple GEM (T-GEM) amplification structure followed by the strip readout electrode. This article presents a design of new detectors and prototype detector tests.

Hard X-ray spectrum of Cygnus X-1

NASA Technical Reports Server (NTRS)

Nolan, P. L.; Gruber, D. E.; Knight, F. K.; Matteson, J. L.; Rothschild, R. E.; Marshall, F. E.; Levine, A. M.; Primini, F. A.

1981-01-01

Long-term measurements of the hard X-ray spectrum from 3 keV to 8 MeV of the black-hole candidate Cygnus X-1 in its low state are reported. Observations were made from October 26 to November 18, 1977 with the A2 (Cosmic X-ray) and A4 (Hard X-ray and Low-Energy Gamma-Ray) experiments on board HEAO 1 in the spacecraft's scanning mode. The measured spectrum below 200 keV is found to agree well with previous spectra which have been fit by a model of the Compton scattering of optical or UV photons in a very hot plasma of electron temperature 32.4 keV and optical depth 3.9 or 1.6 for spherical or disk geometry, respectively. At energies above 300 keV, however, flux excess is observed which may be accounted for by a distribution of electron temperatures from 15 to about 100 keV.

Applications of a pnCCD detector coupled to columnar structure CsI(Tl) scintillator system in ultra high energy X-ray Laue diffraction

NASA Astrophysics Data System (ADS)

Shokr, M.; Schlosser, D.; Abboud, A.; Algashi, A.; Tosson, A.; Conka, T.; Hartmann, R.; Klaus, M.; Genzel, C.; Strüder, L.; Pietsch, U.

2017-12-01

Most charge coupled devices (CCDs) are made of silicon (Si) with typical active layer thicknesses of several microns. In case of a pnCCD detector the sensitive Si thickness is 450 μm. However, for silicon based detectors the quantum efficiency for hard X-rays drops significantly for photon energies above 10 keV . This drawback can be overcome by combining a pixelated silicon-based detector system with a columnar scintillator. Here we report on the characterization of a low noise, fully depleted 128×128 pixels pnCCD detector with 75×75 μm2 pixel size coupled to a 700 μm thick columnar CsI(Tl) scintillator in the photon range between 1 keV to 130 keV . The excellent performance of the detection system in the hard X-ray range is demonstrated in a Laue type X-ray diffraction experiment performed at EDDI beamline of the BESSY II synchrotron taken at a set of several GaAs single crystals irradiated by white synchrotron radiation. With the columnar structure of the scintillator, the position resolution of the whole system reaches a value of less than one pixel. Using the presented detector system and considering the functional relation between indirect and direct photon events Laue diffraction peaks with X-ray energies up to 120 keV were efficiently detected. As one of possible applications of the combined CsI-pnCCD system we demonstrate that the accuracy of X-ray structure factors extracted from Laue diffraction peaks can be significantly improved in hard X-ray range using the combined CsI(Tl)-pnCCD system compared to a bare pnCCD.

The first search for X-ray polarization in the Centaurus X-3 and Hercules X-1 pulsars

NASA Technical Reports Server (NTRS)

Silver, E. H.; Weisskopf, M. C.; Kestenbaum, H. L.; Long, K. S.; Novick, R.; Wolff, R. S.

1979-01-01

The first search for X-ray polarization in the Cen X-3 and Her X-1 pulsars was performed by the OSO 8 polarimeters in 1975 July and 1975 August, respectively. Three-sigma upper limits to the polarization in Cen X-3 of 13.5% and 19% at 2.6 keV and 5.2 keV, respectively, were obtained when the data were averaged over the pulse and binary periods. The upper limit for Her X-1 at 2.6 keV is 60%. A search for pulse-phase dependent X-ray polarization from both objects was also performed. At the 91% confidence level, emission from Cen X-3 exhibits evidence for X-ray polarization at 2.6 keV that varies with pulse phase. Upper limits to polarization are presented for the leading and trailing edges and peak of the Her X-1 pulse at 2.6 keV.

An observation of the Galactic center hard X-ray source, 1E 1740.7-2942, with the Caltech coded-aperture telescope

NASA Technical Reports Server (NTRS)

Heindl, William A.; Cook, Walter R.; Grunsfeld, John M.; Palmer, David M.; Prince, Thomas A.; Schindler, Stephen M.; Stone, Edward C.

1993-01-01

The Galactic center region hard X-ray source IE 1740.7-2942 has been observed with the Caltech Gamma-Ray Imaging Payload (GRIP) from Alice Springs, Australia, on 1988 April 12 and on 1989 April 3 and 4. We report here results from the 1989 measurements based on 14 hr of observation of the Galactic center region. The observations showed IE 1740.7-2942 to be in its normal state, having a spectrum between 35 and 200 keV characterized by a power law with an exponent of -2.2 +/- 0.3 and flux at 100 keV of (7.0 +/- 0.7) x 10 exp -5 sq cm s keV. No flux was detected above 200 keV. A search for time variability in the spectrum of IE 1740.7-2942 on one hour time scales showed no evidence for variability.

First demonstration of 10 keV-width energy-discrimination K-edge radiography using a cadmium-telluride X-ray camera with a tungsten-target tube

NASA Astrophysics Data System (ADS)

Watanabe, Manabu; Sato, Eiichi; Abderyim, Purkhet; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Nagao, Jiro; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-05-01

Energy-discrimination X-ray camera is useful to perform monochromatic radiography using polychromatic X-rays. This X-ray camera was developed to carry out K-edge radiography using cerium and gadolinium-based contrast media. In this camera, objects are irradiated by a cone beam from a tungsten-target X-ray generator, and penetrating X-ray photons are detected by a cadmium-telluride detector with amplifiers. Both optimal photon-energy level and energy width are selected using a multichannel analyzer, and the photon number is counted by a counter card. Radiography was performed by the detector scanning using an x- y stage driven by a two-stage controller, and radiograms were shown on a personal computer monitor. In radiography, tube voltage and current were 90 kV and 5.8 μA, respectively, and the X-ray intensity was 0.61 μGy/s at 1.0 m from the X-ray source. The K-edge energies of cerium and gadolinium are 40.3 and 50.3 keV, respectively, and 10 keV-width enhanced K-edge radiography was performed using X-ray photons with energies just beyond K-edge energies of cerium and gadolinium. Thus, cerium K-edge radiography was carried out using X-ray photons with an energy range from 40.3 to 50. 3 keV, and gadolinium K-edge radiography was accomplished utilizing photon energies ranging from 50.3 to 60.3 keV.

THE NuSTAR Hard X-Ray Survey of the Norma Arm Region

NASA Technical Reports Server (NTRS)

Fornasini, Francesca M.; Tomsick, John A.; Hong, Jaesub; Gotthelf, Eric V.; Bauer, Franz; Rahoui, Farid; Stern, Daniel K.; Bodaghee, Arash; Chiu, Jeng-Lun; Clavel, Maïca;

The NuSTAR Hard X-Ray Survey of the Norma Arm Region

DOE PAGES

Fornasini, Francesca M.; Tomsick, John A.; Hong, JaeSub; ...

2017-04-06

We present a catalog of hard X-ray sources in a square-degree region surveyed by NuSTAR in the direction of the Norma spiral arm. This survey has a total exposure time of 1.7 Ms, and typical and maximum exposure depths of 50 ks and 1 Ms, respectively. In the area of deepest coverage, sensitivity limits of 5 x 10 -14 and 4 x 10-14 erg s -1 cm -2 in the 3–10 and 10–20 keV bands, respectively, are reached. Twenty-eight sources are firmly detected and ten are detected with low significance; eight of the 38 sources are expected to be activemore » galactic nuclei. The three brightest sources were previously identified as a low-mass X-ray binary, high-mass X-ray binary, and pulsar wind nebula. Based on their X-ray properties and multi-wavelength counterparts, we identify the likely nature of the other sources as two colliding wind binaries, three pulsar wind nebulae, a black hole binary, and a plurality of cataclysmic variables (CVs). The CV candidates in the Norma region have plasma temperatures of ≈10–20 keV, consistent with the Galactic Ridge X-ray emission spectrum but lower than temperatures of CVs near the Galactic Center. This temperature difference may indicate that the Norma region has a lower fraction of intermediate polars relative to other types of CVs compared to the Galactic Center. The NuSTAR logN-logS distribution in the 10–20 keV band is consistent with the distribution measured by Chandra at 2–10 keV if the average source spectrum is assumed to be a thermal model with kT ≈ 15 keV, as observed for the CV candidates.« less

Characteristic of x-ray tomography performance using CdTe timepix detector

NASA Astrophysics Data System (ADS)

Zain, R. M.; O'Shea, V.; Maneuski, D.

2017-01-01

X-ray Computed Tomography (CT) is a non-destructive technique for visualizing interior features within solid objects, and for obtaining digital information on their 3-D geometries and properties. The selection of CdTe Timepix detector has a sufficient performance of imaging detector is based on quality of detector performance and energy resolution. The study of Modulation Transfer Function (MTF) shows a 70% contrast at 4 lp/mm was achieved for the 55 µm pixel pitch detector with the 60 kVp X-ray tube and 5 keV noise level. No significant degradation in performance was observed for X-ray tube energies of 20 - 60 keV. The paper discusses the application of the CdTe Timepix detector to produce a good quality image of X-ray tomography imaging.

Single crystal CVD diamond membranes as Position Sensitive X-ray Detector

NASA Astrophysics Data System (ADS)

Desjardins, K.; Menneglier, C.; Pomorski, M.

2017-12-01

Transparent X-ray Beam Position Monitor (XBPM) has been specifically developed for low energy X-ray beamlines (1.4 keV < E < 5 keV) allowing to transmit more than 80% of 2 keV energy beam. The detector is based on a free-standing single crystal CVD diamond membrane of 4 μm thickness with position-sensitive DLC (Diamond-Like Carbon) resistive electrodes in duo-lateral configuration. The measured X-ray beam induced current (XBIC) due to the interaction of X-rays with diamond membrane allows precise monitoring of the absolute beam flux and the beam position (by the reconstruction of its center-of-gravity) at beam transmissions reaching 95%. This detector has been installed at SOLEIL synchrotron on the SIRIUS beamline monochromator output and it has shown charge collection efficiency (CCE) reaching 100% with no lag-effects and excellent beam intensity sensitivity monitoring. X-ray beam mapping of the detector showed an XBIC response inhomogeneity of less than 10% across the membrane, corresponding mainly to the measured variation of the diamond plate thickness. The measured beam position resolution is at sub-micron level depending on the beam flux and the readout electronics bandwidth.

Thermal characteristics of a B8.3 flare observed on July 04, 2009

NASA Astrophysics Data System (ADS)

Awasthi, Arun Kumar; Sylwester, Barbara; Sylwester, Janusz; Jain, Rajmal

We explore the temporal evolution of flare plasma parameters including temperature (T) - differential emission measure (DEM) relationship by analyzing high spectral and temporal cadence of X-ray emission in 1.6-8.0 keV energy band, recorded by SphinX (Polish) and Solar X-ray Spectrometer (SOXS; Indian) instruments, during a B8.3 flare which occurred on July 04, 2009. SphinX records X-ray emission in 1.2-15.0 keV energy band with the temporal and spectral cadence as good as 6 μs and 0.4 keV, respectively. On the other hand, SOXS provides X-ray observations in 4-25 keV energy band with the temporal and spectral resolution of 3 s and 0.7 keV, respectively. We derive the thermal plasma parameters during impulsive phase of the flare employing well-established Withbroe-Sylwester DEM inversion algorithm.

The MXT X-Ray Telescope on Board the SVOM Mission

NASA Astrophysics Data System (ADS)

Götz, D.

2016-10-01

We present the Microchannel X-ray Telescope to be flown on the SVOM mission. The MXT telescope is a compact an light focussing X-ray (0.2-10 keV) instrument based on the coupling of a micropore optics in a narrow field "Lobster -Eye" and a pn CCD.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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 6.4more » 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.« less

Detection of potential periodicities in the unique hard X-ray source Swift J0042.6+4112, dominating the hard X-ray emission in M31

NASA Astrophysics Data System (ADS)

Yukita, Mihoko; Tzanavaris, Panayiotis; Corbet, Robin; Ptak, Andrew; Hornschemeier, Ann; Pottschmidt, Katja; Ballhausen, Ralf; Enoto, Teruaki; Antoniou, Vallia; Lehmer, Bret; Maccarone, Thomas J.; Wik, Daniel; Williams, Ben; Zezas, Andreas

2018-01-01

Recent NuSTAR-Swift observations revealed that a single resolved X-ray source, Swift J0042.6+4112, with Lx of a few times 1038 erg/s dominates the hard X-ray emission from the Andromeda galaxy. HST-based stellar population synthesis modeling combined with the 0.5-50 keV spectral shape suggests that this might be an X-ray pulsar with an intermediate- (or low-) mass donor. Here we further explore the alternative scenario of a symbiotic or ultracompact X-ray binary, based on long-term variability from Swift observations between 2005 and 2016. We find that the soft (0.3-8.0 keV) X-ray flux varies within a factor of 4 but does not exhibit transient behavior. Its power spectrum suggests a 6.1-day period. Additionally, we find a strong 3s-period candidate from both NuSTAR and XMM observations taken in 2017. If interpreted as an orbital and spin period respectively, the source's temporal behavior would not support either the symbiotic or the ultracompact X-ray binary scenario. Rather, it is more consistent with an accreting pulsar with a higher mass donor.

The Chandra Deep Field-South Survey: 7 Ms Source Catalogs

NASA Technical Reports Server (NTRS)

Luo, B.; Brandt, W. N.; Xue, Y. Q.; Lehmer, B.; Alexander, D. M.; Bauer, F. E.; Vito, F.; Yang, G.; Basu-Zych, A. R.; Comastri, A.;

Superiority of Low Energy 160 KV X-Rays Compared to High Energy 6 MV X-Rays in Heavy Element Radiosensitization for Cancer Treatment

NASA Astrophysics Data System (ADS)

Lim, Sara N.; Pradhan, Anil K.; Nahar, Sultana N.; Barth, Rolf F.; Yang, Weilian; Nakkula, Robin J.; Palmer, Alycia; Turro, Claudia

2013-06-01

High energy X-rays in the MeV range are generally employed in conventional radiation therapy from linear accelerators (LINAC) to ensure sufficient penetration depths. However, lower energy X-rays in the keV range may be more effective when coupled with heavy element (high-Z or HZ) radiosensitizers. Numerical simulations of X-ray energy deposition for tumor phantoms sensitized with HZ radiosensitizers were performed using the Monte Carlo code Geant4. The results showed enhancement in energy deposition to radiosensitized phantoms relative to unsensitized phantoms for low energy X-rays in the keV range. In contrast, minimal enhancement was seen using high energy X-rays in the MeV range. Dose enhancement factors (DEFs) were computed and showed radiosensitization only in the low energy range < 200 keV, far lower than the energy of the majority of photons in the LINAC energy range. In vitro studies were carried to demonstrate the tumoricidal effects of HZ sensitized F98 rat glioma cells following irradiation with both low energy 160 kV and high energy 6 MV X-ray sources. The platinum compound, pyridine terpyridine Pt(II) nitrate, was initially used because it was 7x less toxic that an equivalent amount of carboplatin in vitro studies. This would allow us to separate the radiotoxic and the chemotoxic effects of HZ sensitizers. Results from this study showed a 10-fold dose dependent reduction in surviving fractions (SF) of radiosensitized cells treated with low energy 160 kV X-rays compared to those treated with 6 MV X-rays. This is in agreement with our simulations that show an increase in dose deposition in radiosensitized tumors for low energy X-rays. Due to unforeen in vivo toxicity, however, another in vitro study was performed using the commonly used, Pt-based chemotherapeutic drug carboplatin which confirmed earlier results. This lays the ground work for a planned in vivo study using F98 glioma bearing rats. This study demonstrates that while high energy X-rays are commonly used in cancer radiotherapy, low energy keV X-rays might be much more effective with HZ radiosensitization.

X-ray emission from galaxies - The distribution of low-luminosity X-ray sources in the Galactic Centre region

NASA Astrophysics Data System (ADS)

Heard, Victoria; Warwick, Robert

2012-09-01

We report a study of the extended X-ray emission observed in the Galactic Centre (GC) region based on archival XMM-Newton data. The GC diffuse emission can be decomposed into three distinct components: the emission from low-luminosity point sources; the fluorescence of (and reflection from) dense molecular material; and soft (kT ~1 keV), diffuse thermal plasma emission most likely energised by supernova explosions. Here, we examine the emission due to unresolved point sources. We show that this source component accounts for the bulk of the 6.7-keV and 6.9-keV line emission. We fit the surface brightness distribution evident in these lines with an empirical 2-d model, which we then compare with a prediction derived from a 3-d mass model for the old stellar population in the GC region. We find that the X-ray surface brightness declines more rapidly with angular offset from Sgr A* than the mass-model prediction. One interpretation is that the X-ray luminosity per solar mass characterising the GC source population is increasing towards the GC. Alternatively, some refinement of the mass-distribution within the nuclear stellar disc may be required. The unresolved X-ray source population is most likely dominated by magnetic CVs. We use the X-ray observations to set constraints on the number density of such sources in the GC region. Our analysis does not support the premise that the GC is pervaded by very hot (~ 7.5 keV) thermal plasma, which is truly diffuse in nature.

X-ray spectroscopy with silicon pin and avalanche photo diodes

NASA Technical Reports Server (NTRS)

Desai, U. D.

1992-01-01

Results of an evaluation of silicon P-Intrinsic-N (PIN) photodiodes and Avalanche Photodiodes (APD) for the direct detection of soft x rays from 1 to 20 keV and for the detection of scintillation light output from CsI(TI) for higher x ray energies (30 to 1000 keV) are presented. About one keV resolution was achieved at room temperature for both the PIN and APD detectors for soft x rays (1 to 20 keV). Commercially available, low power (18 mV), low noise, hybrid preamplifiers, were used. These photodiodes were also coupled to CsI(TI) scintillator and obtained about 6 resolution at 662 keV. The photodiode frequency response matches well with the emission spectrum of the CsI(TI) scintillator providing good spectral resolution and a higher signal than NaI(TI) when viewed by conventional photomultipliers. A PIN-CsI(TI) combination provides a low energy threshold of around 60 keV while for the APD-CsI(TI) it is 15 keV.

Ellipsoidal and parabolic glass capillaries as condensers for x-ray microscopes.

PubMed

Zeng, Xianghui; Duewer, Fred; Feser, Michael; Huang, Carson; Lyon, Alan; Tkachuk, Andrei; Yun, Wenbing

2008-05-01

Single-bounce ellipsoidal and paraboloidal glass capillary focusing optics have been fabricated for use as condenser lenses for both synchrotron and tabletop x-ray microscopes in the x-ray energy range of 2.5-18 keV. The condenser numerical apertures (NAs) of these devices are designed to match the NA of x-ray zone plate objectives, which gives them a great advantage over zone plate condensers in laboratory microscopes. The fabricated condensers have slope errors as low as 20 murad rms. These capillaries provide a uniform hollow-cone illumination with almost full focusing efficiency, which is much higher than what is available with zone plate condensers. Sub-50 nm resolution at 8 keV x-ray energy was achieved by utilizing this high-efficiency condenser in a laboratory microscope based on a rotating anode generator.

Eclipse and Collapse of the Colliding Wind X-ray Emission from Eta Carinae

NASA Technical Reports Server (NTRS)

Hamaguchi, Kenji; Corcoran, Michael F.

2012-01-01

X-ray emission from the massive stellar binary system, Eta Carinae, drops strongly around periastron passage; the event is called the X-ray minimum. We launched a focused observing campaign in early 2009 to understand the mechanism of causing the X-ray minimum. During the campaign, hard X-ray emission (<10 keV) from Eta Carinae declined as in the previous minimum, though it recovered a month earlier. Extremely hard X-ray emission between 15-25 keV, closely monitored for the first time with the Suzaku HXD/PIN, decreased similarly to the hard X-rays, but it reached minimum only after hard X-ray emission from the star had already began to recover. This indicates that the X-ray minimum is produced by two composite mechanisms: the thick primary wind first obscured the hard, 2-10 keV thermal X-ray emission from the wind-wind collision (WWC) plasma; the WWC activity then decays as the two stars reach periastron.

Cryogenic, high-resolution x-ray detector with high count rate capability

DOEpatents

Frank, Matthias; Mears, Carl A.; Labov, Simon E.; Hiller, Larry J.; Barfknecht, Andrew T.

2003-03-04

A cryogenic, high-resolution X-ray detector with high count rate capability has been invented. The new X-ray detector is based on superconducting tunnel junctions (STJs), and operates without thermal stabilization at or below 500 mK. The X-ray detector exhibits good resolution (.about.5-20 eV FWHM) for soft X-rays in the keV region, and is capable of counting at count rates of more than 20,000 counts per second (cps). Simple, FET-based charge amplifiers, current amplifiers, or conventional spectroscopy shaping amplifiers can provide the electronic readout of this X-ray detector.

Reflectivity around the gold L-edges of x-ray reflector of the soft x-ray telescope onboard ASTRO-H

NASA Astrophysics Data System (ADS)

Maeda, Yoshitomo; Kikuchi, Naomichi; Kurashima, Sho; Ishida, Manabu; Iizuka, Ryo; Hayashi, Takayuki; Okajima, Takashi; Matsumoto, Hironori; Mitsuishi, Ikuyuki; Saji, Shigetaka; Sato, Toshiki; Tachibana, Sasagu; Mori, Hideyuki; Christensen, Finn; Brejnholt, Nicolai; Nitta, Kiyofumi; Uruga, Tomoya

2016-07-01

We report the atomic scattering factor in the 11.2{15.4 keV for the ASTRO-H Soft X-ray Telescope (SXT)9 obtained in the ground based measurements. The large effective area of the SXT covers above 10 keV. In fact, the flight data show the spectra of the celestical objects in the hard X-ray band. In order to model the area, the reflectivity measurements in the 11.2{15.4 keV band with the energy pitch of 0.4 { 0.7 eV were made in the synchrotron beamline Spring-8 BL01B1. We obtained atomic scattering factors f1 and f2 by the curve fitting to the reflectivities of our witness sample. The edges associated with the gold's L-I, II, and III transitions are identified, of which the depths are found to be roughly 60% shallower than those expected from the Henke's atomic scattering factor.

Reflectivity Around the Gold L-Edges of X-Ray Reflector of the Soft X-Ray Telescope Onboard ASTRO-H

NASA Technical Reports Server (NTRS)

Maeda, Yoshitomo; Kikuchi, Naomichi; Kurashima, Sho; Ishida, Manabu; Iizuka, Ryo; Hayashi, Takayuki; Okajima, Takashi; Matsumoto, Hironori; Mitsuishi, Ikuyuki; Saji, Shigetaka;

Resolving the Cygnus X-3 iron K line

NASA Technical Reports Server (NTRS)

Kitamoto, Shunji; Kawashima, Kenji; Negoro, Hitoshi; Miyamoto, Sigenori; White, N. E.; Nagase, Fumiaki

1994-01-01

An Advanced Satellite for Cosmology and Astrophysics (ASCA) observation of Cygnus X-3 on 1993 June 11, in its X-ray high intensity state, has for the first time resolved the broad iron K line emission into three components: a He-like line at 6.67 +/- 0.01 keV, a H-like line at 6.96 +/- 0.02 keV, and a neutral line at 6.37 +/- 0.03 keV. The line intensities of the 6.67 keV and 6.96 keV lines are modulated with the 4.8 hr orbital period and are maximum when the continuum intensity is minimum. There is a sharp minimum of the line intensity on the rising phase of the continuum intensity. An iron absorption edge is observed at 7.19 +/- 0.02 keV. The optical depth of the absorption edge varies from 0.3 to 0.5 and is in anti-phase with the overall X-ray continuum modulation. The observed complexity of the iron K line region is greater than that had been assumed in previous spectral modeling based on observations with lower resolution detectors.

RXTE All-Sky Slew Survey. Catalog of X-Ray Sources at B Greater Than 10 deg

NASA Technical Reports Server (NTRS)

Revnivtsev, M.; Sazonov, S.; Jahoda, K.; Gilfanov, M.

2004-01-01

We report results of a serendipitous hard X-ray (3-20 keV), nearly all-sky (absolute value of b greater than l0 deg.) survey based on RXTE/PCA observations performed during satellite reorientations in 1996-2002. The survey is 80% (90%) complete to a 4(sigma) limiting flux of approx. = 1.8 (2.5) x 10(exp -l1) erg/s sq cm in the 3-20 keV band. The achieved sensitivity in the 3-8 keV and 8-20 keV subbands is similar to and an order of magnitude higher than that of the previously record HEAO-1 A1 and HEAO-1 A4 all-sky surveys, respectively. A combined 7 x 10(exp 3) sq. deg area of the sky is sampled to flux levels below l0(exp -11) erg/ s sq cm (3-20 keV). In total 294 sources are detected and localized to better than 1 deg. 236 (80%) of these can be confidently associated with a known astrophysical object; another 22 likely result from the superposition of 2 or 3 closely located known sources. 35 detected sources remain unidentified, although for 12 of these we report a likely soft X-ray counterpart from the ROSAT all-sky survey bright source catalog. Of the reliably identified sources, 63 have local origin (Milky Way, LMC or SMC), 64 are clusters of galaxies and 100 are active galactic nuclei (AGN). The fact that the unidentified X-ray sources have hard spectra suggests that the majority of them are AGN, including highly obscured ones (N(sub H) greater than l0(exp 23)/sq cm). For the first time we present a log N-log S diagram for extragalactic sources above 4 x l0(exp -12) erg/ s sq cm at 8-20 keV. Key words. cosmo1ogy:observations - diffuse radiation - X-rays general

THz-pump and X-ray-probe sources based on an electron linac.

PubMed

Setiniyaz, Sadiq; Park, Seong Hee; Kim, Hyun Woo; Vinokurov, Nikolay A; Jang, Kyu-Ha; Lee, Kitae; Baek, In Hyung; Jeong, Young Uk

2017-11-01

We describe a compact THz-pump and X-ray-probe beamline, based on an electron linac, for ultrafast time-resolved diffraction applications. Two high-energy electron (γ > 50) bunches, 5 ns apart, impinge upon a single-foil or multifoil radiator and generate THz radiation and X-rays simultaneously. The THz pulse from the first bunch is synchronized to the X-ray beam of the second bunch by using an adjustable optical delay of a THz pulse. The peak power of THz radiation from the multifoil radiator is estimated to be 0.14 GW for a 200 pC well-optimized electron bunch. GEANT4 simulations show that a carbon foil with a thickness of 0.5-1.0 mm has the highest yield of 10-20 keV hard X-rays for a 25 MeV beam, which is approximately 10 3 photons/(keV pC-electrons) within a few degrees of the polar angle. A carbon multifoil radiator with 35 foils (25 μm thick each) can generate close to 10 3 hard X-rays/(keV pC-electrons) within a 2° acceptance angle. With 200 pC charge and a 100 Hz repetition rate, we can generate 10 7 X-rays per 1 keV energy bin per second or 10 5 X-rays per 1 keV energy bin per pulse. The longitudinal time profile of an X-ray pulse ranges from 400 to 600 fs depending on the acceptance angle. The broadening of the time duration of an X-ray pulse is observed owing to its diverging effect. A double-crystal monochromator will be used to select and transport the desired X-rays to the sample. The heating of the radiators by an electron beam is negligible because of the low beam current.

High Resolution, Non-Dispersive X-Ray Calorimeter Spectrometers on EBITs and Orbiting Observatories

NASA Technical Reports Server (NTRS)

Porter, Frederick S.

2010-01-01

X-ray spectroscopy is the primary tool for performing atomic physics with Electron beam ion trap (EBITs). X-ray instruments have generally fallen into two general categories, 1) dispersive instruments with very high spectral resolving powers but limited spectral range, limited count rates, and require an entrance slit, generally, for EBITs, defined by the electron beam itself, and 2) non-dispersive solid-state detectors with much lower spectral resolving powers but that have a broad dynamic range, high count rate ability and do not require a slit. Both of these approaches have compromises that limit the type and efficiency of measurements that can be performed. In 1984 NASA initiated a program to produce a non-dispersive instrument with high spectral resolving power for x-ray astrophysics based on the cryogenic x-ray calorimeter. This program produced the XRS non-dispersive spectrometers on the Astro-E, Astro-E2 (Suzaku) orbiting observatories, the SXS instrument on the Astro-H observatory, and the planned XMS instrument on the International X-ray Observatory. Complimenting these spaceflight programs, a permanent high-resolution x-ray calorimeter spectrometer, the XRS/EBIT, was installed on the LLNL EBIT in 2000. This unique instrument was upgraded to a spectral resolving power of 1000 at 6 keV in 2003 and replaced by a nearly autonomous production-class spectrometer, the EBIT Calorimeter Spectrometer (ECS), in 2007. The ECS spectrometer has a simultaneous bandpass from 0.07 to over 100 keV with a spectral resolving power of 1300 at 6 keV with unit quantum efficiency, and 1900 at 60 keV with a quantum efficiency of 30%. X-ray calorimeters are event based, single photon spectrometers with event time tagging to better than 10 us. We are currently developing a follow-on instrument based on a newer generation of x-ray calorimeters with a spectral resolving power of 3000 at 6 keV, and improved timing and measurement cadence. The unique capabilities of the x-ray calorimeter spectrometer, coupled with higher spectral resolution dispersive spectrometers to resolve line blends, has enabled many science investigations, to date mostly in our x-ray laboratory astrophysics program. These include measurements of absolute cross sections for Land K shell emission from Fe and Ni, charge exchange measurements in many astrophysically abundant elements, lifetime measurements, line ratios, and wavelength measurements. In addition, we have performed many additional measurements in nuclear physics, and in support of diagnostics for laser fusion, for example. In this presentation we will give a detailed overview of x-ray calorimeter instruments in general and in our EBIT laboratory astrophysics program in particular. We will also discuss the science yield of our measurements at EBIT over the last decade) prospects for future science enabled by the current generation of spectrometers and that will be expanded in the near future by the next generation of spectrometers starting in 2611.

Characterizing X-Ray and Radio Emission in the Black Hole X-Ray Binary V404 Cygni During Quiescence

NASA Technical Reports Server (NTRS)

Rana, Vikram; Loh, Alan; Corbel, Stephane; Tomsick, John A.; Chakrabarty, Deepto; Walton, Dominic J.; Barret, Didier; Boggs, Steven E.; Christensen, Finn E.; Craig, William;

An XMM Investigation of Non-Thermal Phenomena in the Winds of Early-Type Stars

NASA Technical Reports Server (NTRS)

Waldron, Wayne L.; Mushotzky, Richard (Technical Monitor)

2002-01-01

The X-ray emission from early-type stars is believed to arise from a stellar wind distribution of shocks. Hence, X-ray analyses of these stars must include the effects of stellar wind X-ray absorption, which, in general dominates the ISM absorption. Although the absorption cross sections for the wind and ISM are essentially identical above 1 keV, there is substantial differences below 1 keV. Typically, if one only uses ISM cross sections to obtain fits to X-ray spectra, the fits usually indicate a model deficiency at energies below 1 keV which is attributed to the large increase in ISM cross sections at these energies. This deficiency can be eliminated by using stellar wind absorption models with a fixed ISM component. Since all early-type stars have substantial X-ray emission below 1 keV, than inclusion of wind absorption has proven to be a critical component in fitting X-ray spectra at low energies, verifying that these X-rays are indeed arising from within the stellar wind.

X-Ray Emission from a Merger Remnant, NGC 7252 (the ``Atoms-for-Peace'' Galaxy)

NASA Astrophysics Data System (ADS)

Awaki, Hisamitsu; Matsumoto, Hironori; Tomida, Hiroshi

2002-03-01

We observed a nearby merger remnant NGC 7252 with the X-ray satellite ASCA and detected X-ray emission with the X-ray flux of (1.8+/-0.3)×10-13 ergs s-1 cm-2 in the 0.5-10 keV band. This corresponds to the X-ray luminosity of 8.1×1040 ergs s-1. The X-ray emission is well described with a two-component model: a soft component with kT=0.72+/-0.13 keV and a hard component with kT>5.1 keV. Although NGC 7252 is referred to as a dynamically young protoelliptical, the 0.5-4 keV luminosity of the soft component is about 2×1040 ergs s-1, which is low for an early-type galaxy. The ratio of LX/LFIR suggests that the soft component originated from the hot gas due to star formation. Its low luminosity can be explained by the gas ejection from the galaxy as galaxy winds. Our observation reveals the existence of hard X-ray emission with the 2-10 keV luminosity of 5.6×1040 ergs s-1. This may indicate the existence of nuclear activity or an intermediate-mass black hole in NGC 7252.

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

NASA Technical Reports Server (NTRS)

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.

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

NASA Technical Reports Server (NTRS)

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..;

WEAK HARD X-RAY EMISSION FROM TWO BROAD ABSORPTION LINE QUASARS OBSERVED WITH NuSTAR: COMPTON-THICK ABSORPTION OR INTRINSIC X-RAY WEAKNESS?

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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 Almost-Equal-To 400-600 hard X-ray ({approx}> 10 keV) photons with NuSTAR, provided that these photons are not significantlymore » absorbed (N{sub H} {approx}< 10{sup 24} cm{sup -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} Almost-Equal-To 7 Multiplication-Sign 10{sup 24} cm{sup -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 K{alpha} 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%.« less

Curved diamond-crystal spectrographs for x-ray free-electron laser noninvasive diagnostics.

PubMed

Terentyev, Sergey; Blank, Vladimir; Kolodziej, Tomasz; Shvyd'ko, Yuri

2016-12-01

We report on the manufacturing and X-ray tests of bent diamond-crystal X-ray spectrographs, designed for noninvasive diagnostics of the X-ray free-electron laser (XFEL) spectra in the spectral range from 5 to 15 keV. The key component is a curved, 20-μm thin, single crystalline diamond triangular plate in the (110) orientation. The radius of curvature can be varied between R = 0.6 m and R = 0.1 m in a controlled fashion, ensuring imaging in a spectral window of up to 60 eV for ≃8 keV X-rays. All of the components of the bending mechanism (about 10 parts) are manufactured from diamond, thus ensuring safe operations in intense XFEL beams. The spectrograph is transparent to 88% for 5-keV photons and to 98% for 15-keV photons. Therefore, it can be used for noninvasive diagnostics of the X-ray spectra during XFEL operations.

Curved diamond-crystal spectrographs for x-ray free-electron laser noninvasive diagnostics

DOE PAGES

Terentyev, Sergey; Blank, Vladimir; Kolodziej, Tomasz; ...

2016-12-29

Here, we report on the manufacturing and X-ray tests of bent diamond-crystal X-ray spectrographs, designed for noninvasive diagnostics of the X-ray free-electron laser (XFEL) spectra in the spectral range from 5 to 15 keV. The key component is a curved, 20-µm thin, single crystalline diamond triangular plate in the (110) orientation. The radius of curvature can be varied between R = 0.6 m and R = 0.1 m in a controlled fashion, ensuring imaging in a spectral window of up to 60 eV for ' 8 keV X-rays. All of the components of the bending mechanism (about 10 parts) aremore » manufactured from diamond, thus ensuring safe operations in intense XFEL beams. The spectrograph is transparent to 88% for 5-keV photons, and to 98% for 15-keV photons. Therefore, it can be used for noninvasive diagnostics of the X-ray spectra during XFEL operations.« less

Curved diamond-crystal spectrographs for x-ray free-electron laser noninvasive diagnostics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Terentyev, Sergey; Blank, Vladimir; Kolodziej, Tomasz

Here, we report on the manufacturing and X-ray tests of bent diamond-crystal X-ray spectrographs, designed for noninvasive diagnostics of the X-ray free-electron laser (XFEL) spectra in the spectral range from 5 to 15 keV. The key component is a curved, 20-µm thin, single crystalline diamond triangular plate in the (110) orientation. The radius of curvature can be varied between R = 0.6 m and R = 0.1 m in a controlled fashion, ensuring imaging in a spectral window of up to 60 eV for ' 8 keV X-rays. All of the components of the bending mechanism (about 10 parts) aremore » manufactured from diamond, thus ensuring safe operations in intense XFEL beams. The spectrograph is transparent to 88% for 5-keV photons, and to 98% for 15-keV photons. Therefore, it can be used for noninvasive diagnostics of the X-ray spectra during XFEL operations.« less

X-ray and radio observations of flares from the RS Canum Venaticorum system UX ARIETIS

NASA Astrophysics Data System (ADS)

Tsuru, T.; Makishima, K.; Ohashi, T.; Inoue, H.; Koyama, K.; Turner, M. J. L.; Barstow, M. A.; McHardy, I. M.; Pye, J. P.; Tsunemi, H.; Kitamoto, S.; Taylor, A. R.; Nelson, R. F.

In July 1987 the RS CVn system UX Ari was observed in the 2-20-keV X-ray band by Ginga, immediately followed by 5-GHz radio observations. UX Ari was found to be very active at both radio and X-ray frequencies. Quiescent X-ray emission with a luminosity of 3 x 10 to the 31st erg/s (in the 2-20-keV band) was detected, together with two intense X-ray flares up to 2 x 10 to the 32nd and 6 x 10 to the 31st erg/s, respectively. Both flare and quiescent X-ray spectra are well fitted by single-temperature thermal bremsstrahlung models, with the continuum temperature and emission measure in the range 4-7 kev (in kT) and (2-10) x 10 to the 54th/cu cm, respectively.

The Marshall Space Flight Center Development of Mirror Modules for the ART-XC Ins1rument Aboard the Spectrum-Roentgen-Gamma Mission

NASA Technical Reports Server (NTRS)

Gubarev, M.; Ramsey, B.; ODell, S. L.; Elsner, R.; Kilaru, K.; McCracken, J.; Pavlinsky, M.; Tkachenko, A.; Lapshov, I.

2012-01-01

The Spectrum-Rontgen-Gamma (SRG) mission is a Russian-German X-ray astrophysical observatory that carries two co-aligned and complementary X-ray telescope systems. The primary instrument is the German-led extended ROentgen Survey with an Imaging Telescope Array (eROSITA), a 7-module X-ray telescope system that covers the energy range from 0.2-12 keV. The complementary instrument is the Russian-led Astronomical Roentgen Telescope -- X-ray Concentrator (ART-XC or ART), a 7-module X-ray telescope system that provides higher energy coverage, up to 30 keV (with limited sensitivity above 12 keV).

CdTe focal plane detector for hard x-ray focusing optics

NASA Astrophysics Data System (ADS)

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

2015-08-01

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 mm x 20 mm CdTe-based detector with 250 μm square pixels (80x80 pixels) which achieves 1 keV FWHM @ 60 keV and gives full spectroscopy between 5 keV and 200 keV. An added advantage of these detectors is that they have a full-frame readout rate of 10 kHz. Working with NASA Goddard Space Flight Center and Marshall Space Flight Center, 4 of these 1mm-thick CdTe detectors are tiled into a 2x2 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 flightsuitable 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.

X-Ray Emission from the Soft X-Ray Transient Aquila X-1

NASA Technical Reports Server (NTRS)

Tavani, Marco

1998-01-01

Aquila X-1 is the most prolific of soft X-ray transients. It is believed to contain a rapidly spinning neutron star sporadically accreting near the Eddington limit from a low-mass companion star. The interest in studying the repeated X-ray outbursts from Aquila X-1 is twofold: (1) studying the relation between optical, soft and hard X-ray emission during the outburst onset, development and decay; (2) relating the spectral component to thermal and non-thermal processes occurring near the magnetosphere and in the boundary layer of a time-variable accretion disk. Our investigation is based on the BATSE monitoring of Aquila X-1 performed by our group. We observed Aquila X-1 in 1997 and re-analyzed archival information obtained in April 1994 during a period of extraordinary outbursting activity of the source in the hard X-ray range. Our results allow, for the first time for this important source, to obtain simultaneous spectral information from 2 keV to 200 keV. A black body (T = 0.8 keV) plus a broken power-law spectrum describe accurately the 1994 spectrum. Substantial hard X-ray emission is evident in the data, confirming that the accretion phase during sub-Eddington limit episodes is capable of producing energetic hard emission near 5 x 10(exp 35) ergs(exp -1). A preliminary paper summarizes our results, and a more comprehensive account is being written. We performed a theoretical analysis of possible emission mechanisms, and confirmed that a non-thermal emission mechanism triggered in a highly sheared magnetosphere at the accretion disk inner boundary can explain the hard X-ray emission. An anticorrelation between soft and hard X-ray emission is indeed prominently observed as predicted by this model.

Second Preliminary Report on X-ray Yields from OMEGA II Targets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fournier, K B; May, M J; MacLaren, S A

2006-08-28

We present details about X-ray yields measured with LLNL and SNL diagnostics in soft and moderately hard X-ray bands from laser-driven, doped-aerogel targets shot on 07/14/06 during the OMEGA II test series. Yields accurate to {+-}25% in the 5-15 keV band are measured with Livermore's HENWAY spectrometer. Yields in the sub-keV to 3.2 keV band are measured with LLNL's DANTE diagnostic, the DANTE yields may be 35-40% too large. SNL ran a PCD-based diagnostic that also measured X-ray yields in the spectral region above 4 keV, and also down to the nearly sub-keV range. The PCD and HENWAY and DANTEmore » numbers are compared. The time histories of the X-ray signals are measured with LLNL's H11 PCD, and from two SNL PCDs with comparable filtering. There is a persistent disagreement between the H11 PCD and SNL PCD measured FWHM, which is shown not to be due to analysis techniques. The recommended X-ray waveform is that from the SNL PCD p66k10, which was recorded on a fast, high-bandwidth TDS 6804 oscilloscope, and which are not plotted here.« less

The Cryogenic AntiCoincidence detector for ATHENA X-IFU: a scientific assessment of the observational capabilities in the hard X-ray band

NASA Astrophysics Data System (ADS)

D'Andrea, M.; Lotti, S.; Macculi, C.; Piro, L.; Argan, A.; Gatti, F.

2017-12-01

ATHENA is a large X-ray observatory, planned to be launched by ESA in 2028 towards an L2 orbit. One of the two instruments of the payload is the X-IFU: a cryogenic spectrometer based on a large array of TES microcalorimeters, able to perform integral field spectrography in the 0.2-12 keV band (2.5 eV FWHM at 6 keV). The X-IFU sensitivity is highly degraded by the particle background expected in the L2 orbit, which is induced by primary protons of both galactic and solar origin, and mostly by secondary electrons. To reduce the particle background level and enable the mission science goals, the instrument incorporates a Cryogenic AntiCoincidence detector (CryoAC). It is a 4 pixel TES based detector, placed < 1 mm below the main array. In this paper we report a scientific assessment of the CryoAC observational capabilities in the hard X-ray band (E > 10 keV). The aim of the study has been to understand if the present detector design can be improved in order to enlarge the X-IFU scientific capability on an energy band wider than the TES array. This is beyond the CryoAC baseline, being this instrument aimed to operate as anticoincidence particle detector and not conceived to perform X-ray observations.

Omega Dante Soft X-Ray Power Diagnostic Component Calibration at the National Synchrotron Light Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, K; Weber, F; Dewald, E

2004-04-15

The Dante soft x-ray spectrometer installed on the Omega laser facility at the Laboratory for Laser Energetics, University of Rochester is a twelve-channel filter-edge defined x-ray power diagnostic. It is used to measure the absolute flux from direct drive, indirect drive (hohlraums) and other plasma sources. Calibration efforts using two beam lines, U3C (50eV-1keV) and X8A (1keV-6keV) at the National Synchrotron Light Source (NSLS) have been implemented to insure the accuracy of these measurements. We have calibrated vacuum x-ray diodes, mirrors and filters.

Hard X-ray Flux from Low-Mass Stars in the Cygnus OB2 Association

NASA Astrophysics Data System (ADS)

Caramazza, M.; Drake, J. J.; Micela, G.; Flaccomio, E.

2009-05-01

We investigate the X-ray emission in the 20-40 keV band expected from the flaring low-mass stellar population in Cygnus OB2 assuming that the observed soft X-ray emission is due to a superposition of flares and that the ratio of hard X-ray to soft X-ray emission is described by a scaling found for solar flares by Isola and co-workers. We estimate a low-mass stellar hard X-ray flux in the 20-40 keV band in the range ~7×1031-7×1033 erg/s and speculate the limit of this values. Hard X-ray emission could lie at a level not much below the current observed flux upper limits for Cygnus OB2. Simbol-X, with its broad energy band (10-100 keV) and its sensitivity should be able to detect this emission and would provide insights into the hard X-ray production of flares on pre-main sequence stars.

Simbol-X: a formation flight mission with an unprecedented imaging capability in the 0.5-80 keV energy band

NASA Astrophysics Data System (ADS)

Tagliaferri, Gianpiero; Ferrando, Philippe; Le Duigou, Jean-Michel; Pareschi, Giovanni; Laurent, Philippe; Malaguti, Giuseppe; Clédassou, Rodolphe; Piermaria, Mauro; La Marle, Olivier; Fiore, Fabrizio; Giommi, Paolo

2017-11-01

The discovery of X-ray emission from cosmic sources in the 1960s has opened a new powerful observing window on the Universe. In fact, the exploration of the X-ray sky during the 70s-90s has established X-ray astronomy as a fundamental field of astrophysics. Today, the emission from astrophysical sources is by large best known at energies below 10 keV. The main reason for this situation is purely technical since grazing incidence reflection has so far been limited to the soft X-ray band. Above 10 keV all the observations have been obtained with collimated detectors or coded mask instruments. To make a leap step forward in Xray astronomy above 10 keV it is necessary to extend the principle of focusing X ray optics to higher energies, up to 80 keV and beyond. To this end, ASI and CNES are presently studying the implementation of a X-ray mission called Simbol-X. Taking advantage of emerging technology in mirror manufacturing and spacecraft formation flying, Simbol-X will push grazing incidence imaging up to 80 keV and beyond, providing a strong improvement both in sensitivity and angular resolution compared to all instruments that have operated so far above 10 keV. This technological breakthrough will open a new highenergy window in astrophysics and cosmology. Here we will address the problematic of the development for such a distributed and deformable instrument. We will focus on the main performances of the telescope, like angular resolution, sensitivity and source localization. We will also describe the specificity of the calibration aspects of the payload distributed over two satellites and therefore in a not "frozen" configuration.

Luminescence imaging of water during irradiation of X-ray photons lower energy than Cerenkov- light threshold

NASA Astrophysics Data System (ADS)

Yamamoto, Seiichi; Koyama, Shuji; Komori, Masataka; Toshito, Toshiyuki

2016-10-01

Luminescence imaging of water using X-ray photon irradiation at energy lower than maximum energy of 200 keV is thought to be impossible because the secondary electrons produced in this energy range do not emit Cerenkov- light. Contrary to this consensus assumption, we show that the luminescence imaging of water can be achieved by X-ray irradiation at energy lower than 120 keV. We placed water phantoms on a table with a conventional X-ray imaging system, and luminescence images of these phantoms were measured with a high-sensitivity, cooled charge coupled device (CCD) camera during X-ray photon irradiation at energy below 120 keV. We also carried out such imaging of an acrylic block and plastic scintillator. The luminescence images of water phantoms taken during X-ray photon irradiation clearly showed X-ray photon distribution. The intensity of the X-ray photon images of the phantom increased almost proportionally to the number of X-ray irradiations. Lower-energy X-ray photon irradiation showed lower-intensity luminescence at the deeper parts of the phantom due to the higher X-ray absorption in the water phantom. Furthermore, lower-intensity luminescence also appeared at the deeper parts of the acrylic phantom due to its higher density than water. The intensity of the luminescence for water was 0.005% of that for plastic scintillator. Luminescence imaging of water during X-ray photon irradiation at energy lower than 120 keV was possible. This luminescence imaging method is promising for dose estimation in X-ray imaging systems.

Determination of Differential Emission Measure Distribution of Coronal Structures Observed by SphinX During Recent Minimum of Solar Activity

NASA Astrophysics Data System (ADS)

Kepa, Anna; Gburek, Szymon; Siarkowski, Marek; Sylwester, Barbara; Sylwester, Janusz; Kowalinski, Miroslaw

SphinX is a high-sensitivity soft X-ray spectrophotometer which measures soft X-ray spectra in the energy range between 0.8 keV and 15 keV. From February to November 2009 the instrument has observed unusually quiet solar coronal emission as well as a number of weak solar flares. Based on SphinX spectra it is possible to study the differential emission measure distributions (DEM) in the temperature range roughly between 1 MK and 10 MK. The aim of the present study is to unveil DEM plasma distributions for selected activity conditions and analyze their variability.

The hard x-ray imager onboard IXO

NASA Astrophysics Data System (ADS)

Nakazawa, Kazuhiro; Takahashi, Tadayuki; Limousin, Olivier; Kokubun, Motohide; Watanabe, Shin; Laurent, Philippe; Arnaud, Monique; Tajima, Hiroyasu

2010-07-01

The Hard X-ray Imager (HXI) is one of the instruments onboard International X-ray Observatory (IXO), to be launched into orbit in 2020s. It covers the energy band of 10-40 keV, providing imaging-spectroscopy with a field of view of 8 x 8 arcmin2. The HXI is attached beneath the Wide Field Imager (WFI) covering 0.1-15 keV. Combined with the super-mirror coating on the mirror assembly, this configuration provides observation of X-ray source in wide energy band (0.1-40.0 keV) simultaneously, which is especially important for varying sources. The HXI sensor part consists of the semiconductor imaging spectrometer, using Si in the medium energy detector and CdTe in the high energy detector as its material, and an active shield covering its back to reduce background in orbit. The HXI technology is based on those of the Japanese-lead new generation X-ray observatory ASTRO-H, and partly from those developed for Simbol-X. Therefore, the technological development is in good progress. In the IXO mission, HXI will provide a major assets to identify the nature of the object by penetrating into thick absorbing materials and determined the inherent spectral shape in the energy band well above the structure around Fe-K lines and edges.

The Ophiuchus cluster - A bright X-ray cluster of galaxies at low galactic latitude

NASA Technical Reports Server (NTRS)

Johnston, M. D.; Bradt, H. V.; Doxsey, R. E.; Marshall, F. E.; Schwartz, D. A.; Margon, B.

1981-01-01

The discovery of an extended X-ray source identified with a cluster of galaxies at low galactic latitude is reported. The source, designated the Ophiuchus cluster, was detected near 4U 1708-23 with the HEAO 1 Scanning Modulation Collimator, and identified with the cluster on the basis of extended X-ray size and positional coincidence on the ESO/SRC (J) plate of the region. An X-ray flux density in the region 2-10 keV of approximately 25 microJ was measured, along with an X-ray luminosity of 1.6 x 10 to the 45th ergs/sec and an X-ray core radius of approximately 4 arcmin (0.2 Mpc) for an assumed isothermal sphere surface brightness distribution. The X-ray spectrum in the range 2-10 keV obtained with the HEAO 1 A-2 instrument is well fit by a thermal bremsstrahlung model with kT = 8 keV and a 6.7-keV iron line of equivalent width 450 eV. The steep-spectrum radio source MSH 17-203 also appears to be associated with the cluster, which is the closest and brightest representative of the class of X-ray clusters with a dominant central galaxy.

Gamma-ray lens development status for a European gamma-ray imager

NASA Astrophysics Data System (ADS)

Frontera, F.; Pisa, A.; Carassiti, V.; Evangelisti, F.; Loffredo, G.; Pellicciotta, D.; Andersen, K. H.; Courtois, P.; Amati, L.; Caroli, E.; Franceschini, T.; Landini, G.; Silvestri, S.; Stephen, J. B.

2006-06-01

A breakthrough in the sensitivity level of the hard X-/gamma-ray telescopes, which today are based on detectors that view the sky through (or not) coded masks, is expected when focusing optics will be available also in this energy range. Focusing techniques are now in an advanced stage of development. To date the most efficient technique to focus hard X-rays with energies above 100 keV appears to be the Bragg diffraction from crystals in transmission configuration (Laue lenses). Crystals with mosaic structure appear to be the most suitable to build a Laue lens with a broad passband, even though other alternative structures are being investigated. The goal of our project is the development of a broad band focusing telescope based on gamma-ray lenses for the study of the continuum emission of celestial sources from 60 keV up to >600 keV. We will report details of our project, its development status and results of our assessment study of a lens configuration for the European Gamma Ray Imager (GRI) mission now under study for the ESA plan Cosmic Vision 2015-2025.

Identification of the Hard X-Ray Source Dominating the E > 25 keV Emission of the Nearby Galaxy M31

NASA Technical Reports Server (NTRS)

Yukita, M.; Ptak, A.; Hornschemeier, A. E.; Wik, D.; Maccarone, T. J.; Pottschmidt, K.; Zezas, A.; Antoniou, V.; Ballhausen, R.; Lehmer, B. D.;

Extensive Broadband X-Ray Monitoring During the Formation of a Giant Radio Jet Base in Cyg X-3 with AstroSat

NASA Astrophysics Data System (ADS)

Pahari, Mayukh; Yadav, J. S.; Verdhan Chauhan, Jai; Rawat, Divya; Misra, Ranjeev; Agrawal, P. C.; Chandra, Sunil; Bagri, Kalyani; Jain, Pankaj; Manchanda, R. K.; Chitnis, Varsha; Bhattacharyya, Sudip

2018-01-01

We present X-ray spectral and timing behavior of Cyg X-3 as observed by AstroSat during the onset of a giant radio flare on 2017 April 1–2. Within a timescale of a few hours, the source shows a transition from the hypersoft state (HPS) to a more luminous state (we termed as the very high state), which coincides with the time of the steep rise in radio flux density by an order of magnitude. Modeling the Soft X-ray Telescope (SXT) and Large Area X-ray Proportional Counter (LAXPC) spectra jointly in 0.5–70.0 keV, we found that the first few hours of the observation is dominated by the HPS with no significant counts above 17 keV. Later, an additional flat power-law component suddenly appeared in the spectra that extends to very high energies with the power-law photon index of {1.49}-0.03+0.04. Such a flat power-law component has never been reported from Cyg X-3. Interestingly the fitted power-law model in 25–70 keV, when extrapolated to the radio frequency, predicts the radio flux density to be consistent with the trend measured from the RATAN-600 telescope at 11.2 GHz. This provides direct evidence of the synchrotron origin of flat X-ray power-law component and the most extensive monitoring of the broadband X-ray behavior at the moment of decoupling the giant radio jet base from the compact object in Cyg X-3. Using SXT and LAXPC observations, we determine the giant flare ejection time as MJD 57845.34 ± 0.08 when 11.2 GHz radio flux density increases from ∼100 to ∼478 mJy.

MAXI/GSC 7-year Source Catalog

NASA Astrophysics Data System (ADS)

Ueda, Y.; Kawamuro, T.; Hori, T.; Shidatsu, M.; Tanimoto, A.; MAXI Team

2017-10-01

Monitor of All-sky X-ray Image (MAXI) on the International Space Station has been continuously observing the X-ray sky since its launch in 2009. The MAXI survey has achieved the best sensitivity in the 4-10 keV band as an all sky X-ray mission, and is complementary to the ROSAT all sky survey (<2 keV) and hard X-ray (>10 keV) surveys performed with Swift and INTEGRAL. Here we present the latest source catalog of MAXI/Gas Slit Camera (GSC) constructed from the first 7-year data, which is an extension of the 37-month catalog of the high Galactic-latitude sky (Hiroi et al. 2013). We summarize statistical properties of the X-ray sources and results of cross identification with other catalogs.

Ionized Absorbers in Active Galactic Nuclei and Very Steap Soft X-Ray Quasars

NASA Technical Reports Server (NTRS)

Fiore, Fabrizio; White, Nicholas (Technical Monitor)

2000-01-01

Steep soft X-ray (0.1-2 keV) quasars share several unusual properties: narrow Balmer lines, strong Fe II emission, large and fast X-ray variability, and a rather steep 2-10 keV spectrum. These intriguing objects have been suggested to be the analogues of Galactic black hole candidates in the high, soft state. We present here results from ASCA observations for two of these quasars: NAB 0205 + 024 and PG 1244 + 026. Both objects show similar variations (factor of approximately 2 in 10 ks), despite a factor of approximately 10 difference in the 0.5-10 keV luminosity (7.3 x 10(exp 43) erg/s for PG 1244 + 026 and 6.4 x 10(exp 44) erg/s for NAB 0205 + 024, assuming isotropic emission, H(sub 0) = 50.0 and q(sub 0) = 0.0). The X-ray continuum of the two quasars flattens by 0.5-1 going from the 0.1-2 keV band towards higher energies, strengthening recent results on another half-dozen steep soft X-ray active galactic nuclei. PG 1244 + 026 shows a significant feature in the '1-keV' region, which can be described either as a broad emission line centered at 0.95 keV (quasar frame) or as edge or line absorption at 1.17 (1.22) keV. The line emission could be a result of reflection from a highly ionized accretion disc, in line with the view that steep soft X-ray quasars are emitting close to the Eddington luminosity. Photoelectric edge absorption or resonant line absorption could be produced by gas outflowing at a large velocity (0.3-0.6 c).

High repetition rate compact source of nanosecond pulses of 5-100 keV x-ray photons

NASA Astrophysics Data System (ADS)

Khacef, A.; Viladrosa, R.; Cachoncinlle, C.; Robert, E.; Pouvesle, J. M.

1997-06-01

A powerful, compact, and repetitive flash x-ray system based on a cable transformer technology powered by ceramic capacitors in a Blumlein-like configuration has been developed. Open circuit voltages in excess of 100 kV can be achieved while commutation occurs at low voltage (<20 kV). The x-ray emission from a low impedance x-ray diode with a hollow cathode configuration was observed under a wide range of experimental conditions. The critical parameters limiting the flash x-ray performances are mainly the pressure in the x-ray diode and the anode-cathode space. This true table top device is able to produce doses up to 1 R per shot, measured at the output window, of x-rays between 5 and 100 keV. The pulse widths were about 20 ns and the maximum repetition rate was about 60 Hz. Operation is possible in air or in other gases (He, Ne, Ar, Kr, Xe, H2, N2) at pressures varying from 10-3 mbar for xenon to about 1 mbar for helium.

Contrast cancellation technique applied to digital x-ray imaging using silicon strip detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avila, C.; Lopez, J.; Sanabria, J. C.

2005-12-15

Dual-energy mammographic imaging experimental tests have been performed using a compact dichromatic imaging system based on a conventional x-ray tube, a mosaic crystal, and a 384-strip silicon detector equipped with full-custom electronics with single photon counting capability. For simulating mammal tissue, a three-component phantom, made of Plexiglass, polyethylene, and water, has been used. Images have been collected with three different pairs of x-ray energies: 16-32 keV, 18-36 keV, and 20-40 keV. A Monte Carlo simulation of the experiment has also been carried out using the MCNP-4C transport code. The Alvarez-Macovski algorithm has been applied both to experimental and simulated datamore » to remove the contrast between two of the phantom materials so as to enhance the visibility of the third one.« less

Variability of the symbiotic X-ray binary GX 1+4. Enhanced activity near periastron passage

NASA Astrophysics Data System (ADS)

Iłkiewicz, Krystian; Mikołajewska, Joanna; Monard, Berto

2017-05-01

Context. GX 1+4 belongs to a rare class of X-ray binaries with red giant donors, symbiotic X-ray binaries. It has a history of complicated variability on multiple timescales in the optical light and X-rays. The nature of this variability remains poorly understood. Aims: We aim to study variability of GX 1+4 on long timescale in X-ray and optical bands. Methods: We took X-ray observations from the INTEGRAL Soft Gamma-Ray Imager and RXTE All Sky Monitor. Optical observations were made with the INTEGRAL Optical Monitoring Camera. Results: The variability of GX 1+4 both in optical light and hard X-ray emission (>17 keV) is dominated by 50-70 d quasi-periodic changes. The amplitude of this variability is highest during the periastron passage, while during the potential neutron star eclipse the system is always at minimum. This confirms the 1161 d orbital period that has had been proposed for the system based on radial velocity curve. Neither the quasi-periodic variability or the orbital period are detected in soft X-ray emission (1.3-12.2 keV), where the binary shows no apparent periodicity.

Advanced X-ray Astrophysics Facility (AXAF): An overview

NASA Technical Reports Server (NTRS)

Weisskopf, M. C.; ODell, S. L.; Elsner, R. F.; VanSpeybroeck, L. P.

1995-01-01

The Advanced X-ray Astrophysics Facility (AXAF) is the x-ray component of NASA's Great Observatories. To be launched in late 1998, AXAF will provide unprecedented capabilities for high-resolution imaging, spectrometric imaging, and high-resolution disperse spectroscopy, over the x-ray band from about 0.1 keV to 10 keV. With these capabilities, AXAF observations will address many of the outstanding questions in astronomy, astrophysics, and cosmology.

Discovery of Oxygen Kalpha X-ray Emission from the Rings of Saturn

NASA Technical Reports Server (NTRS)

Bhardwaj, Anil; Elsner, Ronald F.; Waite, J. Hunter, Jr.; Gladstone, G Randall; Cravens, Thomas E.; Ford, Peter G.

2005-01-01

Using the Advanced CCD Imaging Spectrometer (ACIS), the Chandra X-ray Observatory (CXO) observed the Saturnian system for one rotation of the planet (approx.37 ks) on 20 January, 2004, and again on 26-27 January, 2004. In this letter we report the detection of X-ray emission from the rings of Saturn. The X-ray spectrum from the rings is dominated by emission in a narrow (approx.130 eV wide) energy band centered on the atomic oxygen Ka fluorescence line at 0.53 keV. The X-ray power emitted from the rings in the 0.49-0.62 keV band is about one-third of that emitted from Saturn disk in the photon energy range 0.24-2.0 keV. Our analysis also finds a clear detection of X-ray emission from the rings in the 0.49-0.62 keV band in an earlier (14-15 April, 2003) Chandra ACIS observation of Saturn. Fluorescent scattering of solar X-rays from oxygen atoms in the H20 icy ring material is the likely source mechanism for ring X-rays, consistent with the scenario of solar photo-production of a tenuous ring oxygen atmosphere and ionosphere recently discovered by Cassini.

Preparation of relatively clean carbon backings used in charged particle induced x-ray studies for x-rays below 4 KeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kocur, P.; Duggan, J.L.; McDaniel, F.D.

1983-04-01

In a recent series of studies of M-shell ionization induced by protons, alpha particles, and fluorine ions, an unmanageable background of low energy contaminant x rays was observed. These K-shell x rays were primarily from Ca, K, Cl, S, P, Si and Na. The energy range of these contaminants is from 3.691 to 1.041 keV. The M-shell x rays being studied were for various elements from U ( about 3.5 keV) down to Eu (1.5 keV). In order to evaluate and reduce the problem, the contaminants for carbon foils from a number of different manufacturers and a wide variety ofmore » foil float-off procedures have been studied. Carbon foils have been produced in our laboratory using carbon rods from several different manufacturers. In this paper, techniques will be described that are most appropriate to reduce the above contaminants to a reasonable level. These techniques should be useful in trace element analysis (PIXE) studies and fundamental ionization measurements for low x-ray energies.« less

Circumstellar X-ray Emission from SN1978K

NASA Astrophysics Data System (ADS)

Schlegel, Eric M.; Colbert, E.; Petre, R.

1995-02-01

We present the X-ray light curve in the 0.2 2.4 keV band based on fiveROSAT observations of SN1978K in NGC 1313. The X-ray emission is believed to arise from the interaction of the reverse shock and the expanding debris from the supernova. The reverse shock becomes established after the outgoing shock runs into circumstellar matter.

Diagnostic X-ray sources-present and future

NASA Astrophysics Data System (ADS)

Behling, Rolf; Grüner, Florian

2018-01-01

This paper compares very different physical principles of X-ray production to spur ideation. Since more than 120 years, bremsstrahlung from X-ray tubes has been the workhorse of medical diagnostics. Generated by X-ray segments comprised of X-ray tubes and high-voltage generators in the various medical systems, X-ray photons in the spectral range between about 16 keV and 150 keV deliver information about anatomy and function of human patients and in pre-clinical animal studies. Despite of strides to employ the wave nature of X-rays as phase sensitive means, commercial diagnostic X-ray systems available until the time of writing still rely exclusively on measuring the attenuation and scattering of X-rays by matter. Significant activities in research aim at building highly brilliant short pulse X-ray sources, based on e.g. synchrotron radiation, free electron lasers and/or laser wake-field acceleration of electrons followed by wiggling with magnetic structures or Thomson scattering in bunches of light. While both approaches, non-brilliant and brilliant sources, have different scope of application, we speculate that a combination may expand the efficacy in medical application. At this point, however, severe technical and commercial difficulties hinder closing this gap. This article may inspire further development and spark innovation in this important field.

Extremely Hard X-ray Emission from Eta Carinae observed with XMM-Newton and NuSTAR around Periastron in 2014.5

NASA Astrophysics Data System (ADS)

Hamaguchi, Kenji; Corcoran, Michael F.; Takahashi, Hiromitsu; Yuasa, Tadayuki; Groh, Jose H.; Russell, Christopher Michael Post; Pittard, Julian M.; Madura, Thomas; Owocki, Stanley P.; Grefenstette, Brian

2015-01-01

The super massive colliding wind binary system, Eta Carinae, experienced another periastron passage in the summer of 2014. We monitored this event using the multiple X-ray observatories, Chandra, XMM-Newton, NuSTAR, Suzaku and Swift. With a high eccentricity of its 5.5 year orbit, X-ray emission from the wind-wind collision (WWC) increases strongly toward periastron but then drops sharply by more than two orders of magnitude in two weeks around periastron due probably to an eclipse and an intrinsic activity decline of the WWC plasma. In this observing campaign, XMM-Newton and NuSTAR coordinated two simultaneous observations around the X-ray flux maximum on June 6 and just before the flux minimum on July 28. These two observations captured Eta Carinae with X-ray focusing telescopes in the extreme hard X-ray band above 10 keV for the first time.During the first observation, XMM and NuSTAR detected stable X-ray emission from the central binary system between 1 - 40 keV. A fit of a 1-temperature bremsstrahlung model to the high energy slope in the NuSTAR spectrum derives an electron temperature of ~6 keV, which is significantly higher than an ionization temperature at ~4.5 keV, measured from the Fe K emission lines resolved in the XMM spectrum.This result suggests the presence of very hot plasma and/or X-ray reflection at surrounding cold material. During the second observation, the X-ray flux between 5 - 10 keV declined steadily by a factor of ~2 in a day, while the other energy bands were rather stable. This variation may be explained by an increase of the line of sight absorption to emission from the plasma component that dominates above 5 keV. NuSTAR did not detect, in either observation, the very hard non-thermal component that dominated emission above 25 keV seen in earlier INTEGRAL and Suzaku observations. We discuss the plasma condition and the wind structure of Eta Carinae around periastron, and the nature of the non-thermal component.

An Ultradeep Chandra Catalog of X-Ray Point Sources in the Galactic Center Star Cluster

NASA Astrophysics Data System (ADS)

Zhu, Zhenlin; Li, Zhiyuan; Morris, Mark R.

2018-04-01

We present an updated catalog of X-ray point sources in the inner 500″ (∼20 pc) of the Galactic center (GC), where the nuclear star cluster (NSC) stands, based on a total of ∼4.5 Ms of Chandra observations taken from 1999 September to 2013 April. This ultradeep data set offers unprecedented sensitivity for detecting X-ray sources in the GC, down to an intrinsic 2–10 keV luminosity of 1.0 × 1031 erg s‑1. A total of 3619 sources are detected in the 2–8 keV band, among which ∼3500 are probable GC sources and ∼1300 are new identifications. The GC sources collectively account for ∼20% of the total 2–8 keV flux from the inner 250″ region where detection sensitivity is the greatest. Taking advantage of this unprecedented sample of faint X-ray sources that primarily traces the old stellar populations in the NSC, we revisit global source properties, including long-term variability, cumulative spectra, luminosity function, and spatial distribution. Based on the equivalent width and relative strength of the iron lines, we suggest that in addition to the arguably predominant population of magnetic cataclysmic variables (CVs), nonmagnetic CVs contribute substantially to the detected sources, especially in the lower-luminosity group. On the other hand, the X-ray sources have a radial distribution closely following the stellar mass distribution in the NSC, but much flatter than that of the known X-ray transients, which are presumably low-mass X-ray binaries (LMXBs) caught in outburst. This, together with the very modest long-term variability of the detected sources, strongly suggests that quiescent LMXBs are a minor (less than a few percent) population.

Discovery of Diffuse Hard X-ray Emission associated with Jupiter

NASA Astrophysics Data System (ADS)

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.

The Hard X-ray Imager (HXI) for the ASTRO-H mission

NASA Astrophysics Data System (ADS)

Kokubun, Motohide; Nakazawa, Kazuhiro; Enoto, Teruaki; Fukazawa, Yasushi; Kataoka, Jun; Kawaharada, Madoka; Laurent, Philippe; Lebrun, François; Limousin, Olivier; Makishima, Kazuo; Mizuno, Tsunefumi; Mori, Kunishiro; Nakamori, Takeshi; Odaka, Hirokazu; Ohno, Masanori; Ohta, Masayuki; Sato, Goro; Sato, Rie; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Tanaka, Takaaki; Terada, Yukikatsu; Uchiyama, Hideki; Uchiyama, Yasunobu; Watanabe, Shin; Yatsu, Yoichi; Yuasa, Takayuki

2012-09-01

The Hard X-ray Imager (HXI) is one of the four detectors on board the ASTRO-H mission (6th Japanese X-ray satellite), which is scheduled to be launched in 2014. Using the hybrid structure composed of double-sided silicon strip detectors and a cadmium telluride double-sided strip detector, both with a high spatial resolution of 250 μm. Combined with the hard X-ray telescope (HXT), it consists a hard X-ray imaging spectroscopic instrument covering the energy range from 5 to 80 keV with an effective area of <300 cm2 in total at 30 keV. An energy resolution of 1-2 keV (FWHM) and lower threshold of 5 keV are both achieved with using a low noise front-end ASICs. In addition, the thick BGO active shields surrounding the main detector package is a heritage of the successful performance of the Hard X-ray Detector on board the Suzaku satellite. This feature enables the instrument to achieve an extremely good reduction of background caused by cosmic-ray particles, cosmic X-ray background, and in-orbit radiation activation. In this paper, we present the detector concept, design, latest results of the detector development, and the current status of the hardware.

Broadband high resolution X-ray spectral analyzer

DOEpatents

Silver, Eric H.; Legros, Mark; Madden, Norm W.; Goulding, Fred; Landis, Don

1998-01-01

A broad bandwidth high resolution x-ray fluorescence spectrometer has a performance that is superior in many ways to those currently available. It consists of an array of 4 large area microcalorimeters with 95% quantum efficiency at 6 keV and it produces x-ray spectra between 0.2 keV and 7 keV with an energy resolution of 7 to 10 eV. The resolution is obtained at input count rates per array element of 10 to 50 Hz in real-time, with analog pulse processing and thermal pile-up rejection. This performance cannot be matched by currently available x-ray spectrometers. The detectors are incorporated into a compact and portable cryogenic refrigerator system that is ready for use in many analytical spectroscopy applications as a tool for x-ray microanalysis or in research applications such as laboratory and astrophysical x-ray and particle spectroscopy.

Broadband high resolution X-ray spectral analyzer

DOEpatents

Silver, E.H.; Legros, M.; Madden, N.W.; Goulding, F.; Landis, D.

1998-07-07

A broad bandwidth high resolution X-ray fluorescence spectrometer has a performance that is superior in many ways to those currently available. It consists of an array of 4 large area microcalorimeters with 95% quantum efficiency at 6 keV and it produces X-ray spectra between 0.2 keV and 7 keV with an energy resolution of 7 to 10 eV. The resolution is obtained at input count rates per array element of 10 to 50 Hz in real-time, with analog pulse processing and thermal pile-up rejection. This performance cannot be matched by currently available X-ray spectrometers. The detectors are incorporated into a compact and portable cryogenic refrigerator system that is ready for use in many analytical spectroscopy applications as a tool for X-ray microanalysis or in research applications such as laboratory and astrophysical X-ray and particle spectroscopy. 6 figs.

Eta Carinae's Thermal X-Ray Tail Measured with XMM-Newton and NuStar

NASA Technical Reports Server (NTRS)

Hamaguchi, Kenji; Corcoran, Michael F.; Gull, Theodore R.; Takahashi, Hiromitsu; Grefenstette, Brian; Yuasa, Takayuki; Stuhlinger, Martin; Russell, Christopher; Moffat, Anthony F. J.; Madura, Thomas

2016-01-01

The evolved, massive highly eccentric binary system, Car, underwent a periastron passage in the summer of 2014. We obtained two coordinated X-ray observations with XMM-Newton and NuSTAR during the elevated X-ray flux state and just before the X-ray minimum flux state around this passage. These NuSTAR observations clearly detected X-ray emission associated with eta Car extending up to approx. 50 keV for the first time. The NuSTAR spectrum above 10 keV can be fit with the bremsstrahlung tail from a kT approx. 6 keV plasma. This temperature is delta kT 2 keV higher than those measured from the iron K emission line complex, if the shocked gas is in collisional ionization equilibrium. 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 X-ray emission by 40% at energies above 5 keV in a day, the largest rate of change of the X-ray flux yet observed in individual eta Car observations. The column density to the hardest emission component, N(sub H) approx. 10(exp24) H cm(exp-2), marked one of the highest values ever observed for eta Car, strongly suggesting the increased obscuration of the wind-wind colliding 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. The power-law source might have faded before these observations.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakrabarty, Deepto; Nowak, Michael A.; Tomsick, John A.

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 thermalmore » 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.« less

A study of 2-20 KeV X-rays from the Cygnus region

NASA Technical Reports Server (NTRS)

Bleach, R. D.

1972-01-01

Two rocket-borne proportional counters, each with 650 sq c, met area and 1.8 x 7.1 deg FWHM rectangular mechanical collimation, surveyed the Cygnus region in the 2 to 20 keV energy range on two occasions. X-ray spectral data gathered on 21 September 1970 from discrete sources in Cygnus are presented. The data from Cyg X-1, Cyg X-2, and Cyg X-3 have sufficient statistical significance to indicate mutually exclusive spectral forms for the three. Upper limits are presented for X-ray intensities above 2 keV for Cyg X-4 and Cyg X-5 (Cygnus loop). A search was made on 9 August 1971 for a diffuse component of X-rays 1.5 keV associated with an interarm region of the galaxy at galactic longitudes in the vicinity of 60 degrees. A statistically significant excess associated with a narrow disk component was detected. Several possible emission models are discussed, with the most likely candidate being a population of unresolvable low luminosity discrete sources.

ASCA Observation of an "X-Ray Shadow" in the Galactic Plane

NASA Technical Reports Server (NTRS)

Park, Sangwook; Ebisawa, Ken

2001-01-01

The diffuse X-ray background (DXB) emission near the Galactic plane (l,b approximately 25.6 degrees, 0.78 degrees) has been observed with ASCA (Advanced Satellite for Cosmology and Astrophysics). The observed region is toward a Galactic molecular cloud which was recently reported to cast a deep X-ray shadow in the 0.5 - 2.0 keV band DXB. The selection of this particular region is intended to provide a constraint on the spatial distribution of the DXB emission along the line of sight: i.e., the molecular cloud is optically thick at <2 keV and so the bulk of the observed soft X-rays must originate in the foreground of the cloud, which is at approximately 3 kpc from the Sun. In the 0.8 - 9.0 keV band, the observed spectrum is primarily from multiple components of thermal plasmas. We here report a detection of soft X-ray (0.5 - 2 keV) emission from an approximately 10(exp 7) K thermal plasma. Comparisons with the ROSAT (Roentgen Satellite) data suggest that this soft X-ray emission is absorbed by N(sub H) = 1 - 3 x 10(exp 21) cm(exp -2), which implies a path-length through the soft X-ray emitting regions of approximately less than 1 kpc from the Sun.

Weak hard X-ray emission from broad absorption line quasars: evidence for intrinsic X-ray weakness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, B.; Brandt, W. N.; Scott, A. E.

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 < 1.3. However, their rest-frame ≈2 keV luminosities are 14 to >330 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,more » 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 ≲ 45 counts in the 3-24 keV band, and the other three 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 (Γ{sub eff} ≈ 1.8) for this sample disfavors Compton-thick absorption in general. The uniform hard X-ray weakness observed by NuSTAR for this and the pilot samples selected with <10 keV weakness also suggests that the X-ray weakness is intrinsic in at least some of the targets. We conclude that the NuSTAR observations have likely discovered a significant population (≳ 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.« less

X-ray spectrometer with a low-cost SiC photodiode

NASA Astrophysics Data System (ADS)

Zhao, S.; Lioliou, G.; Barnett, A. M.

2018-04-01

A low-cost Commercial-Off-The-Shelf (COTS) 4H-SiC 0.06 mm2 UV p-n photodiode was coupled to a low-noise charge-sensitive preamplifier and used as photon counting X-ray spectrometer. The photodiode/spectrometer was investigated at X-ray energies from 4.95 keV to 21.17 keV: a Mo cathode X-ray tube was used to fluoresce eight high-purity metal foils to produce characteristic X-ray emission lines which were used to characterise the instrument. The energy resolution (full width at half maximum, FWHM) of the spectrometer was found to be 1.6 keV to 1.8 keV, across the energy range. The energy linearity of the detector/spectrometer (i.e. the detector's charge output per photon as a function of incident photon energy across the 4.95 keV to 21.17 keV energy range), as well as the count rate linearity of the detector/spectrometer (i.e. number of detected photons as a function of photon fluence at a specific energy) were investigated. The energy linearity of the detector/spectrometer was linear with an error < ± 0.7 %; the count rate linearity of the detector/spectrometer was linear with an error < ± 2 %. The use of COTS SiC photodiodes as detectors for X-ray spectrometers is attractive for nanosatellite/CubeSat applications (including solar flare monitoring), and for cost sensitive industrial uses.

LABORATORY MEASUREMENTS COMPELLINGLY SUPPORT A CHARGE-EXCHANGE MECHANISM FOR THE “DARK MATTER” ∼3.5 keV X-Ray LINE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shah, Chintan; Dobrodey, Stepan; Bernitt, Sven

2016-12-10

The reported observations of an unidentified X-ray line feature at ∼3.5 keV have driven a lively discussion about its possible dark matter origin. Motivated by this, we have measured the K-shell X-ray spectra of highly ionized bare sulfur ions following charge exchange with gaseous molecules in an electron beam ion trap, as a source of or a contributor to this X-ray line. We produced S{sup 16+} and S{sup 15+} ions and let them capture electrons in collision with those molecules with the electron beam turned off while recording X-ray spectra. We observed a charge-exchange-induced X-ray feature at the Lyman seriesmore » limit (3.47 ± 0.06 keV). The inferred X-ray energy is in full agreement with the reported astrophysical observations and supports the novel scenario proposed by Gu et al.« less

Energy-dependent Orbital Modulation of X-rays and Constraints on Emission of the Jet in Cyg X-3

NASA Technical Reports Server (NTRS)

Zdziarski, Andrzej A.; Maitra, Chandreyee; Frankowski, Adam; Skinner, Gerald K.; Misra, Ranjeev

2012-01-01

We study orbital modulation of X-rays from Cyg X-3, using data from Swift, INTEGRAL and RXTE. Using the wealth of the presently available data and an improved averaging method, we obtain energy-dependent folded and averaged light curves with unprecedented accuracy. We find that above 5 keV, the modulation depth decreases with the increasing energy, which is consistent with the modulation being caused by both bound-free absorption and Compton scattering in the stellar wind of the donor, with minima corresponding to the highest optical depth, which occurs around the superior conjunction. We find a decrease of the depth below 3 keV, which appears to be due to re-emission of the absorbed continuum by the wind in soft X-ray lines. Based on the shape of the folded light curves, any X-ray contribution from the jet in Cyg X-3, which emits ?-rays detected at energies > 0.1 GeV in soft spectral states, is found to be minor up to 100 keV. This implies the presence of a rather sharp low-energy break in the jet MeV-range spectrum.We also calculate phase-resolved RXTE X-ray spectra, and show the difference between the spectra corresponding to phases around the superior and inferior conjunctions can indeed be accounted for by a combined effect of bound-free absorption in an ionized medium and Compton scattering.

Observations of 12-200 keV X-rays from GX 339-4

NASA Technical Reports Server (NTRS)

Nolan, P. L.; Gruber, D. E.; Knight, F. K.; Matteson, J. L.; Peterson, L. E.; Levine, A. M.; Lewin, W. H. G.; Primini, F. A.

1982-01-01

X-ray spectra of GX 339-4 measured on three occasions in 1977 and 1978 are presented. These are the first reported measurements above 10 keV. The spectra can be described as the superposition of a soft component, which is dominant below about 20 keV, and a hard component at higher energy. Simultaneous measurements at lower energy show that the soft component vanished during the observation in early 1978. The behavior of these two components is similar to that of the spectrum of Cygnus X-1; this reinforces the previously noted resemblance in rapid X-ray variability.

Note: A disposable x-ray camera based on mass produced complementary metal-oxide-semiconductor sensors and single-board computers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoidn, Oliver R.; Seidler, Gerald T., E-mail: seidler@uw.edu

We have integrated mass-produced commercial complementary metal-oxide-semiconductor (CMOS) image sensors and off-the-shelf single-board computers into an x-ray camera platform optimized for acquisition of x-ray spectra and radiographs at energies of 2–6 keV. The CMOS sensor and single-board computer are complemented by custom mounting and interface hardware that can be easily acquired from rapid prototyping services. For single-pixel detection events, i.e., events where the deposited energy from one photon is substantially localized in a single pixel, we establish ∼20% quantum efficiency at 2.6 keV with ∼190 eV resolution and a 100 kHz maximum detection rate. The detector platform’s useful intrinsic energymore » resolution, 5-μm pixel size, ease of use, and obvious potential for parallelization make it a promising candidate for many applications at synchrotron facilities, in laser-heating plasma physics studies, and in laboratory-based x-ray spectrometry.« less

The weak Fe fluorescence line and long-term X-ray evolution of the Compton-thick active galactic nucleus in NGC 7674

NASA Astrophysics Data System (ADS)

Gandhi, P.; Annuar, A.; Lansbury, G. B.; Stern, D.; Alexander, D. M.; Bauer, F. E.; Bianchi, S.; Boggs, S. E.; Boorman, P. G.; Brandt, W. N.; Brightman, M.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Del Moro, A.; Elvis, M.; Guainazzi, M.; Hailey, C. J.; Harrison, F. A.; Koss, M.; Lamperti, I.; Malaguti, G.; Masini, A.; Matt, G.; Puccetti, S.; Ricci, C.; Rivers, E.; Walton, D. J.; Zhang, W. W.

2017-06-01

We present NuSTAR X-ray observations of the active galactic nucleus (AGN) in NGC 7674. The source shows a flat X-ray spectrum, suggesting that it is obscured by Compton-thick gas columns. Based upon long-term flux dimming, previous work suggested the alternate possibility that the source is a recently switched-off AGN with the observed X-rays being the lagged echo from the torus. Our high-quality data show the source to be reflection-dominated in hard X-rays, but with a relatively weak neutral Fe Kα emission line (equivalent width [EW] of ≈ 0.4 keV) and a strong Fe xxvi ionized line (EW ≈ 0.2 keV). We construct an updated long-term X-ray light curve of NGC 7674 and find that the observed 2-10 keV flux has remained constant for the past ≈ 20 yr, following a high-flux state probed by Ginga. Light travel time arguments constrain the minimum radius of the reflector to be ˜ 3.2 pc under the switched-off AGN scenario, ≈ 30 times larger than the expected dust sublimation radius, rendering this possibility unlikely. A patchy Compton-thick AGN (CTAGN) solution is plausible, requiring a minimum line-of-sight column density (NH) of 3 × 1024 cm-2 at present, and yields an intrinsic 2-10 keV luminosity of (3-5) × 1043 erg s-1. Realistic uncertainties span the range of ≈ (1-13) × 1043 erg s-1. The source has one of the weakest fluorescence lines amongst bona fide CTAGN, and is potentially a local analogue of bolometrically luminous systems showing complex neutral and ionized Fe emission. It exemplifies the difficulty of identification and proper characterization of distant CTAGN based on the strength of the neutral Fe Kα line.

X-ray fluorescence cross sections for K and L x rays of the elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krause, M.O.; Nestor, C.W. Jr.; Sparks, C.J. Jr.

1978-06-01

X-ray fluorescence cross sections are calculated for the major x rays of the K series 5 less than or equal to Z less than or equal to 101, and the three L series 12 less than or equal to Z less than or equal to 101 in the energy range 1 to 200 keV. This calculation uses Scofield's theoretical partical photoionization cross sections, Krause's evaluation of fluorescence and Coster-Kronig yields, and Scofield's theoretical radiative rates. Values are presented in table and graph format, and an estimate of their accuracy is made. The following x rays are considered: K..cap alpha../sub 1/,more » K..cap alpha../sub 1/,/sub 2/, K..beta../sub 1/, K..beta../sub 1/,/sub 3/, L..cap alpha../sub 1/, L..cap alpha../sub 1/,/sub 2/, L..beta../sub 1/, L..beta../sub 2/,/sub 15/, L..beta../sub 3/, Ll, L..gamma../sub 1/, L..gamma../sub 4/, and L/sub 1/ ..-->.. L/sub 2/,/sub 3/. For use in x-ray fluorescence analysis, K..cap alpha.. and L..cap alpha.. fluorescence cross sections are presented at specific energies: TiK identical with 4.55 keV, CrK identical with 5.46 keV, CoK identical with 7.00 keV, CuK identical with 8.13 keV, MoK..cap alpha.. identical with 17.44 keV, AgK identical with 22.5 keV, DyK identical with 47.0 keV, and /sup 241/Am identical with 59.54 keV. Supplementary material includes fluorescence and Coster--Kronig yields, fractional radiative rates, fractional fluorescence yields, total L-shell fluorescence cross sections, fluorescence and Coster-Kronig yields in condensed matter, effective fluorescence yields, average L-shell fluorescence yield, L-subshell photoionization cross section ratios, and conversion factors from barns per atom to square centimeters per gram.« less

A sealed titanium window proportional counter for the detection of .5-keV X rays.

NASA Technical Reports Server (NTRS)

Mcclintock, J. E.; Levine, A.; Rappaport, S.

1972-01-01

A sealed Ti window proportional counter sensitive to X radiation in the energy range 0.35-0.45 keV and above 1.5 keV is described. Measurements of the Ti mass absorption coefficients and a graphical summary of the literature values are presented. For a proportional counter with a 930 microgram/sq cm (2.1-micron) Ti window, the peak efficiency at 0.45 keV is found to lie between 4.6% and 7.1%. An application in X-ray astronomy involving a rocket observation of Sco X-1 is discussed.

BAT AGN Spectroscopic Survey. V. X-Ray Properties of the Swift/BAT 70-month AGN Catalog

NASA Astrophysics Data System (ADS)

Ricci, C.; Trakhtenbrot, B.; Koss, M. J.; Ueda, Y.; Del Vecchio, I.; Treister, E.; Schawinski, K.; Paltani, S.; Oh, K.; Lamperti, I.; Berney, S.; Gandhi, P.; Ichikawa, K.; Bauer, F. E.; Ho, L. C.; Asmus, D.; Beckmann, V.; Soldi, S.; Baloković, M.; Gehrels, N.; Markwardt, C. B.

2017-12-01

Hard X-ray (≥10 keV) observations of active galactic nuclei (AGNs) can shed light on some of the most obscured episodes of accretion onto supermassive black holes. The 70-month Swift/BAT all-sky survey, which probes the 14-195 keV energy range, has currently detected 838 AGNs. We report here on the broadband X-ray (0.3-150 keV) characteristics of these AGNs, obtained by combining XMM-Newton, Swift/XRT, ASCA, Chandra, and Suzaku observations in the soft X-ray band (≤slant 10 keV) with 70-month averaged Swift/BAT data. The nonblazar AGNs of our sample are almost equally divided into unobscured ({N}{{H}}< {10}22 {{cm}}-2) and obscured ({N}{{H}}≥slant {10}22 {{cm}}-2) AGNs, and their Swift/BAT continuum is systematically steeper than the 0.3-10 keV emission, which suggests that the presence of a high-energy cutoff is almost ubiquitous. We discuss the main X-ray spectral parameters obtained, such as the photon index, the reflection parameter, the energy of the cutoff, neutral and ionized absorbers, and the soft excess for both obscured and unobscured AGNs.

NuSTAR Observations of Heavily Obscured Quasars at z Is Approximately 0.5

NASA Technical Reports Server (NTRS)

Lansbury, G. B.; Alexander, D. M.; Del Moro, A.; Gandhi, P.; Assef, R. J.; Stern, D.; Aird, J.; Ballantyne, D. R.; Balokovic, M.; Bauer, F. E.;

Multi-keV X-ray area source intensity at SGII laser facility

NASA Astrophysics Data System (ADS)

Wang, Rui-rong; An, Hong-hai; Xie, Zhi-yong; Wang, Wei

2018-05-01

Experiments for investigating the feasibility of multi-keV backlighters for several different metallic foil targets were performed at the Shenguang II (SGII) laser facility in China. Emission spectra in the energy range of 1.65-7.0 keV were measured with an elliptically bent crystal spectrometer, and the X-ray source size was measured with a pinhole camera. The X-ray intensity near 4.75 keV and the X-ray source size for titanium targets at different laser intensity irradiances were studied. By adjusting the total laser energy at a fixed focal spot size, laser intensity in the range of 1.5-5.0 × 1015 W/cm2, was achieved. The results show that the line emission intensity near 4.75 keV and the X-ray source size are dependent on the laser intensity and increase as the laser intensity increases. However, an observed "peak" in the X-ray intensity near 4.75 keV occurs at an irradiance of 4.0 × 1015 W/cm2. For the employed experimental conditions, it was confirmed that the laser intensity could play a significant role in the development of an efficient multi-keV X-ray source. The experimental results for titanium indicate that the production of a large (˜350 μm in diameter) intense backlighter source of multi-keV X-rays is feasible at the SGII facility.

Performance of NICER flight x-ray concentrator

NASA Astrophysics Data System (ADS)

Okajima, Takashi; Soong, Yang; Balsamo, Erin R.; Enoto, Teruaki; Olsen, Larry; Koenecke, Richard; Lozipone, Larry; Kearney, John; Fitzsimmons, Sean; Numata, Ai; Kenyon, Steven J.; Arzoumanian, Zaven; Gendreau, Keith

2016-07-01

Neutron star Interior Composition ExploreR (NICER) is a NASA instrument to be onboard International Space Station, which is equipped with 56 pairs of an X-ray concentrator (XRC) and a silicon drift detector for high timing observations. The XRC is based on an epoxy replicated thin aluminum foil X-ray mirror, similar to those of Suzaku and ASTRO-H (Hitomi), but only a single stage parabolic grazing incidence optic. Each has a focal length of 1.085m and a diameter of 105 mm, with 24 confocally aligned parabolic shells. Grazing incident angles to individual shells range from 0.4 to 1.4 deg. The flight 56 XRCs have been completed and successfully delivered to the payload integration. All the XRC was characterized at the NASA/GSFC 100-m X-ray beamline using 1.5 keV X-rays (some of them are also at 4.5 keV). The XRC performance, effective area and point spread function, was measured by a CCD camera and a proportional counter. The average effective area is about 44 cm2 at 1.5 keV and about 18 cm2 at 4.5 keV, which is consistent with a micro-roughness of 0.5nm from individual shell reflectivity measurements. The XRC focuses about 91% of X-rays into a 2mm aperture at the focal plane, which is the NICER detector window size. Each XRC weighs only 325 g. These performance met the project requirement. In this paper, we will present summary of the flight XRC performance as well as co-alignment results of the 56 XRCs on the flight payload as it is important to estimate the total effective for astronomical observations.

High-Resolution X-Ray Spectra of the Symbiotic Star SS73 17

NASA Technical Reports Server (NTRS)

Eze, R. N. C.; Luna, G. J. M.; Smith, R. K.

2010-01-01

SS73 17 was an innocuous Mira-type symbiotic star until the International Gamma-Ray Astrophysics Laboratory and Swift discovered its bright hard X-ray emission, adding it to the small class of "hard X-ray emitting symbiotics." Suzaku observations in 2006 then showed it emits three bright iron lines as well, with little to no emission in the 0.3-2.0 keV bandpass. We present here follow-up observations with the Chandra High Energy Transmission Grating and Suzaku that confirm the earlier detection of strong emission lines of Fe K(alpha) fluorescence, Fe XXV and Fe XXVI but also show significantly more soft X-ray emission. The high-resolution spectrum also shows emission lines of other highly ionized ions as Si xiv and possibly S XVI. In addition, a re-analysis of the 2006 Suzaku data using the latest calibration shows that the hard (15-50 keV) X-ray emission is brighter than previously thought and remains constant in both the 2006 and 2008 data. The G ratio calculated from the Fe xxv lines shows that these lines are thermal, not photoionized, in origin.With the exception of the hard X-ray emission, the spectra from both epochs can be fit using thermal radiation assuming a differential emission measure based on a cooling-flow model combined with a full and partial absorber. We show that acceptable fits can be obtained for all the data in the 1-10 keV band varying only the partial absorber. Based on the temperature and accretion rate, the thermal emission appears to be arising from the boundary layer between the accreting white dwarf and the accretion disk.

X-ray micro-Tomography at the Advanced Light Source

USDA-ARS?s Scientific Manuscript database

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

CALET Upper Limits on X-Ray and Gamma-Ray Counterparts of GW151226

NASA Astrophysics Data System (ADS)

Adriani, O.; Akaike, Y.; Asano, K.; Asaoka, Y.; Bagliesi, M. G.; Bigongiari, G.; Binns, W. R.; Bonechi, S.; Bongi, M.; Brogi, P.; Buckley, J. H.; Cannady, N.; Castellini, G.; Checchia, C.; Cherry, M. L.; Collazuol, G.; Di Felice, V.; Ebisawa, K.; Fuke, H.; Guzik, T. G.; Hams, T.; Hareyama, M.; Hasebe, N.; Hibino, K.; Ichimura, M.; Ioka, K.; Ishizaki, W.; Israel, M. H.; Javaid, A.; Kasahara, K.; Kataoka, J.; Kataoka, R.; Katayose, Y.; Kato, C.; Kawanaka, N.; Kawakubo, Y.; Kitamura, H.; Krawczynski, H. S.; Krizmanic, J. F.; Kuramata, S.; Lomtadze, T.; Maestro, P.; Marrocchesi, P. S.; Messineo, A. M.; Mitchell, J. W.; Miyake, S.; Mizutani, K.; Moiseev, A. A.; Mori, K.; Mori, M.; Mori, N.; Motz, H. M.; Munakata, K.; Murakami, H.; Nakagawa, Y. E.; Nakahira, S.; Nishimura, J.; Okuno, S.; Ormes, J. F.; Ozawa, S.; Pacini, L.; Palma, F.; Papini, P.; Penacchioni, A. V.; Rauch, B. F.; Ricciarini, S.; Sakai, K.; Sakamoto, T.; Sasaki, M.; Shimizu, Y.; Shiomi, A.; Sparvoli, R.; Spillantini, P.; Stolzi, F.; Takahashi, I.; Takayanagi, M.; Takita, M.; Tamura, T.; Tateyama, N.; Terasawa, T.; Tomida, H.; Torii, S.; Tsunesada, Y.; Uchihori, Y.; Ueno, S.; Vannuccini, E.; Wefel, J. P.; Yamaoka, K.; Yanagita, S.; Yoshida, A.; Yoshida, K.; Yuda, T.

2016-09-01

We present upper limits in the hard X-ray and gamma-ray bands at the time of the Laser Interferometer Gravitational-wave Observatory (LIGO) gravitational-wave event GW151226 derived from the CALorimetric Electron Telescope (CALET) observation. The main instrument of CALET, CALorimeter (CAL), observes gamma-rays from ˜1 GeV up to 10 TeV with a field of view of ˜2 sr. The CALET gamma-ray burst monitor (CGBM) views ˜3 sr and ˜2π sr of the sky in the 7 keV-1 MeV and the 40 keV-20 MeV bands, respectively, by using two different scintillator-based instruments. The CGBM covered 32.5% and 49.1% of the GW151226 sky localization probability in the 7 keV-1 MeV and 40 keV-20 MeV bands respectively. We place a 90% upper limit of 2 × 10-7 erg cm-2 s-1 in the 1-100 GeV band where CAL reaches 15% of the integrated LIGO probability (˜1.1 sr). The CGBM 7σ upper limits are 1.0 × 10-6 erg cm-2 s-1 (7-500 keV) and 1.8 × 10-6 erg cm-2 s-1 (50-1000 keV) for a 1 s exposure. Those upper limits correspond to the luminosity of 3-5 × 1049 erg s-1, which is significantly lower than typical short GRBs.

RS Ophiuchi in Quiescence: Why Is It X-ray Faint?

NASA Technical Reports Server (NTRS)

Mukai, Koji

2007-01-01

The short interval between successive outbursts of RS Oph strongly suggests that it has a high mass white dwarf accreting at a high rate. This, in turn, suggests the possibility of prominent X-ray emission from RS Oph in quiescence. However, archival quiescent X-ray observations of RS Oph show it to be a modest soft X-ray source but not a strong 2-10 keV X-ray source. In this aspect, RS Oph differs markedly from T CrB. We speculate on the possible mechanisms that could significantly suppress the 2-10 keV X-ray emission in RS Oph.

X-ray observations of two short but intense solar flares

NASA Technical Reports Server (NTRS)

Nitta, Nariaki; Dennis, Brian R.; Kiplinger, Alan L.

1990-01-01

This paper presents continuum X-ray spectra of impulsive emission in two short but intense solar flares which have relatively weak soft X-ray emissions, combining data obtained with soft X-ray and hard X-ray spectrometers on board two satellites, the SMM and Hinotori. In both flares, photon spectra of the impulsive component are found to flatten toward low energies, suggesting that a low-energy cutoff of the electron spectrum could be greater than about 50 keV and that the total energy contained in the electrons is significantly less than that usually quoted for a cutoff energy of about 20 keV. Different shapes of the X-ray spectrum at energies below 50 keV in other flares can be attributed to the variety in the relative strength of gradual and impulsive emissions. In one of the two flares, observations with the imager on Hinotori suggest that hard X-ray emission is likely to be associated with loop footpoints. It is argued that contamination by the gradual soft X-ray emission and/or the asymmetry of loops could explain the detection of single sources in the majority of flares that have been imaged in hard X-rays.

The average 0.5-200 keV spectrum of local active galactic nuclei and a new determination of the 2-10 keV luminosity function at z ≈ 0

NASA Astrophysics Data System (ADS)

Ballantyne, D. R.

2014-01-01

The broad-band X-ray spectra of active galactic nuclei (AGNs) contains information about the nuclear environment from Schwarzschild radii scales (where the primary power law is generated in a corona) to distances of ˜1 pc (where the distant reflector may be located). In addition, the average shape of the X-ray spectrum is an important input into X-ray background synthesis models. Here, local (z ≈ 0) AGN luminosity functions (LFs) in five energy bands are used as a low-resolution, luminosity-dependent X-ray spectrometer in order to constrain the average AGN X-ray spectrum between 0.5 and 200 keV. The 15-55 keV LF measured by Swift-BAT is assumed to be the best determination of the local LF, and then a spectral model is varied to determine the best fit to the 0.5-2 keV, 2-10 keV, 3-20 keV and 14-195 keV LFs. The spectral model consists of a Gaussian distribution of power laws with a mean photon-index <Γ> and cutoff energy Ecut, as well as contributions from distant and disc reflection. The reflection strength is parametrized by varying the Fe abundance relative to solar, AFe, and requiring a specific Fe Kα equivalent width (EW). In this way, the presence of the X-ray Baldwin effect can be tested. The spectral model that best fits the four LFs has <Γ> = 1.85 ± 0.15, E_{cut}=270^{+170}_{-80} keV, A_{Fe}=0.3^{+0.3}_{-0.15}. The sub-solar AFe is unlikely to be a true measure of the gas-phase metallicity, but indicates the presence of strong reflection given the assumed Fe Kα EW. Indeed, parametrizing the reflection strength with the R parameter gives R=1.7^{+1.7}_{-0.85}. There is moderate evidence for no X-ray Baldwin effect. Accretion disc reflection is included in the best-fitting model, but it is relatively weak (broad iron Kα EW < 100 eV) and does not significantly affect any of the conclusions. A critical result of our procedure is that the shape of the local 2-10 keV LF measured by HEAO-1 and MAXI is incompatible with the LFs measured in the hard X-rays by Swift-BAT and RXTE. We therefore present a new determination of the local 2-10 keV LF that is consistent with all other energy bands, as well as the de-evolved 2-10 keV LF estimated from the XMM-Newton Hard Bright Survey. This new LF should be used to revise current measurements of the evolving AGN LF in the 2-10 keV band. Finally, the suggested absence of the X-ray Baldwin effect points to a possible origin for the distant reflector in dusty gas not associated with the AGN obscuring medium. This may be the same material that produces the compact 12 μm source in local AGNs.

T-REX: Thomson-Radiated Extreme X-rays Moving X-Ray Science into the ''Nuclear'' Applications Space with Thompson Scattered Photons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barty, C P; Hartemann, F V

2004-09-21

The scattering of laser photons from relativistic electrons (Thomson scattering) has been demonstrated to be a viable method for the production of ultrashort-duration pulses of tunable radiation in the 10-keV to 100-keV range. Photons in this range are capable of exciting or ionizing even the most tightly bound of atomic electrons. A wide variety of atomistic scale applications are possible. For example, Thomson x-ray sources have been constructed at LLNL (PLEIADES) and LBL as picosecond, stroboscopic probes of atomic-scale dynamics and at Vanderbilt University as element-specific tools for medical radiography and radiology. While these sources have demonstrated an attractive abilitymore » to simultaneously probe on an atomic spatial and temporal scale, they do not necessarily exploit the full potential of the Thomson scattering process to produce high-brightness, high-energy photons. In this white paper, we suggest that the peak brightness of Thomson sources can scale as fast as the 4th power of electron beam energy and that production via Thomson scattering of quasi-monochromatic, tunable radiation in the ''nuclear-range'' between 100-keV and several MeV is potentially a much more attractive application space for this process. Traditional sources in this regime are inherently ultra-broadband and decline rapidly in brightness as a function of photon energy. The output from dedicated, national-laboratory-scale, synchrotron facilities, e.g. APS, SPring8, ESRF etc., declines by more than 10 orders from 100 keV to 1 MeV. At 1 MeV, we conservatively estimate that Thomson-source, peak brightness can exceed that of APS (the best machine in the DOE complex) by more than 15 orders of magnitude. In much the same way that tunable lasers revolutionized atomic spectroscopy, this ''Peta-step'' advance in tunable, narrow-bandwidth, capability should enable entirely new fields of study and new, programmatically-interesting, applications such as: micrometer-spatial-resolution, MeV, flash radiography of dense, energetic systems (NIF, JASPER), precision, photo-nuclear absorption spectroscopy (DNT, PAT), non-destructive, resonant nuclear fluorescent imaging of special nuclear materials (NAI, DHS), dynamic, micro-crack failure analysis (aerospace industry, SSP) etc. Concepts are presented for new Thomson-Radiated Extreme X-ray (T-REX) sources at LLNL. These leverage LLNL's world-leading expertise in high-intensity lasers, high average power lasers, diffractive optics, Thomson-based x-ray source development, and advanced photoguns to produce tunable, quasi-monochromatic radiation from 50-keV to several MeV. Above {approx}100 keV, T-REX would be unique in the world with respect to BOTH peak x-ray brilliance AND average x-ray brilliance. This capability would naturally compliment the x-ray capability of large-scale, synchrotron facilities currently within the DoE complex by significantly extending the x-ray energy range over which, tunable, high-brightness applications could be pursued. It would do so at a small fraction of the cost of the purely, accelerator-based facilities. It is anticipated that T-REX could provide new opportunities for interaction of LLNL with the DoE Office of Science, DARPA, DHS etc. and would place LLNL clearly at the forefront of laser-based, x-ray generation world-wide.« less

Nustar Reveals an Intrinsically X-ray Weak Broad Absorption Line Quasar in the Ultraluminous Infrared Galaxy Markarian 231

NASA Technical Reports Server (NTRS)

Teng, Stacy H.; Brandt. W. N.; Harrison, F. A.; Luo, B.; Alexander, D. M.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W.;

Statistical analysis of tiny SXR flares observed by SphinX

NASA Astrophysics Data System (ADS)

Gryciuk, Magdalena; Siarkowski, Marek; Sylwester, Janusz; Kepa, Anna; Gburek, Szymon; Mrozek, Tomasz; Podgórski, Piotr

2015-08-01

The Solar Photometer in X-rays (SphinX) was designed to observe soft X-ray solar emission in the energy range between ~1 keV and 15 keV with the resolution better than 0.5 keV. The instrument operated from February until November 2009 aboard CORONAS-Photon satellite, during the phase of exceptionally low minimum of solar activity. Here we use SphinX data for analysis of micro-flares and brightenings. Despite a very low activity more than a thousand small X-ray events have been recognized by semi-automatic inspection of SphinX light curves. A catalogue of temporal and physical characteristics of these events is shown and discussed and results of the statistical analysis of the catalogue data are presented.

The Morphology of the X-ray Emission above 2 keV from Jupiter's Aurorae

NASA Technical Reports Server (NTRS)

Elsner, R.; Branduardi-Raymont, G.; Galand, M.; Grodent, D.; Waite, J. H.; Cravens, T.; Ford, P.

2007-01-01

The discovery in XMM-Newton X-ray data of X-ray emission above 2 keV from Jupiter's aurorae has led us to reexamine the Chandra ACIS-S observations taken in Feb 2003. Chandra's superior spatial resolution has revealed that the auroral X-rays with E > 2 keV are emitted from the periphery of the region emitting those with E < 1 keV. We are presently exploring the relationship of this morphology to that of the FUV emission from the main auroral oval and the polar cap. The low energy emission has previously been established as due to charge exchange between energetic precipitating ions of oxygen and either sulfur or carbon. It seems likely to us that the higher energy emission is due to precipitation of energetic electrons, possibly the same population of electrons responsible for the FUV emission. We discuss our analysis and interpretation.

Mission and Objectives for the X-1 Advanced Radiation Source*

NASA Astrophysics Data System (ADS)

Rochau, Gary E.; Ramirez, Juan J.; Raglin, Paul S.

1998-11-01

Sandia National Laboratories PO Box 5800, MS-1178, Albuquerque, NM 87185 The X-1 Advanced Radiation Source represents a next step in providing the U.S. Department of Energy's Stockpile Stewardship Program with the high-energy, large volume, laboratory x-ray source for the Radiation Effects Science and Simulation, Inertial Confinement Fusion, and Weapon Physics Programs. Advances in fast pulsed power technology and in z-pinch hohlraums on Sandia National Laboratories' Z Accelerator provide sufficient basis for pursuing the development of X-1. The X-1 plan follows a strategy based on scaling the 2 MJ x-ray output on Z via a 3-fold increase in z-pinch load current. The large volume (>5 cm3), high temperature (>150 eV), temporally long (>10 ns) hohlraums are unique outside of underground nuclear weapon testing. Analytical scaling arguments and hydrodynamic simulations indicate that these hohlraums at temperatures of 230-300 eV will ignite thermonuclear fuel and drive the reaction to a yield of 200 to 1,200 MJ in the laboratory. Non-ignition sources will provide cold x-ray environments (<15 keV) and high yield fusion burn sources will provide high fidelity warm x-ray environments (15 keV-80 keV). This paper will introduce the X-1 Advanced Radiation Source Facility Project, describe the project mission, objective, and preliminary schedule.

Spectral and temporal properties of the X-ray pulsar SMC X-1 at hard X-rays

NASA Technical Reports Server (NTRS)

Kunz, M.; Gruber, D. E.; Kendziorra, E .; Kretschmar, P.; Maisack, M.; Mony, B.; Staubert, R.; Doebereiner, S.; Englhauser, J.; Pietsch, W.

1993-01-01

The binary X-ray pulsar SMC X- 1 has been observed at hard X-rays with the High Energy X-Ray Experiment (HEXE) on nine occasions between Nov. 1987 and March 1989. A thin thermal bremsstrahlung fit to the phase averaged spectrum yields a plasma temperature (14.4 +/- 1.3) keV and a luminosity above (1.1 +/- 0.1) x 10 exp 38 erg/s in the 20-80 keV band. Pulse period values have been established for three observations, confirming the remarkably stable spin-up trend of SMC X-1. In one of the three observations the pulse profile was seen to deviate from a dominant double pulsation, while at the same time the pulsed fraction was unusually large. For one observation we determined for the first time the pulsed fraction in narrow energy bands. It increases with photon energy from about 20 percent up to over 60 percent in the energy range from 20 to 80 keV.

The XMM-SERVS survey: new XMM-Newton point-source catalog for the XMM-LSS field

NASA Astrophysics Data System (ADS)

Chen, C.-T. J.; Brandt, W. N.; Luo, B.; Ranalli, P.; Yang, G.; Alexander, D. M.; Bauer, F. E.; Kelson, D. D.; Lacy, M.; Nyland, K.; Tozzi, P.; Vito, F.; Cirasuolo, M.; Gilli, R.; Jarvis, M. J.; Lehmer, B. D.; Paolillo, M.; Schneider, D. P.; Shemmer, O.; Smail, I.; Sun, M.; Tanaka, M.; Vaccari, M.; Vignali, C.; Xue, Y. Q.; Banerji, M.; Chow, K. E.; Häußler, B.; Norris, R. P.; Silverman, J. D.; Trump, J. R.

2018-04-01

We present an X-ray point-source catalog from the XMM-Large Scale Structure survey region (XMM-LSS), one of the XMM-Spitzer Extragalactic Representative Volume Survey (XMM-SERVS) fields. We target the XMM-LSS region with 1.3 Ms of new XMM-Newton AO-15 observations, transforming the archival X-ray coverage in this region into a 5.3 deg2 contiguous field with uniform X-ray coverage totaling 2.7 Ms of flare-filtered exposure, with a 46 ks median PN exposure time. We provide an X-ray catalog of 5242 sources detected in the soft (0.5-2 keV), hard (2-10 keV), and/or full (0.5-10 keV) bands with a 1% expected spurious fraction determined from simulations. A total of 2381 new X-ray sources are detected compared to previous source catalogs in the same area. Our survey has flux limits of 1.7 × 10-15, 1.3 × 10-14, and 6.5 × 10-15 erg cm-2 s-1 over 90% of its area in the soft, hard, and full bands, respectively, which is comparable to those of the XMM-COSMOS survey. We identify multiwavelength counterpart candidates for 99.9% of the X-ray sources, of which 93% are considered as reliable based on their matching likelihood ratios. The reliabilities of these high-likelihood-ratio counterparts are further confirmed to be ≈97% reliable based on deep Chandra coverage over ≈5% of the XMM-LSS region. Results of multiwavelength identifications are also included in the source catalog, along with basic optical-to-infrared photometry and spectroscopic redshifts from publicly available surveys. We compute photometric redshifts for X-ray sources in 4.5 deg2 of our field where forced-aperture multi-band photometry is available; >70% of the X-ray sources in this subfield have either spectroscopic or high-quality photometric redshifts.

High Spectral Resolution, High Cadence, Imaging X-Ray Microcalorimeters for Solar Physics

NASA Technical Reports Server (NTRS)

Bandler, Simon R.; Bailey, Catherine N.; Bookbinder, Jay A.; DeLuca, Edward E.; Chervenak, Jay A.; Eckart, Megan E.; Finkbeiner, Fred M.; Kelley, Daniel P.; Kelley, Richard L.; Kilbourne, Caroline A.;

Hard x ray observations of Vela X-1 and A0535+26 with HEXE: Discovery of cyclotron lines

NASA Technical Reports Server (NTRS)

Kendziorra, E.; Mony, B.; Kretschmar, P.; Maisack, M.; Staubert, R.; Doebereiner, S.; Englhauser, J.; Pietsch, W.; Reppin, C.; Truemper, J.

1992-01-01

The X ray pulsars Vela X-1 (4U 0900-40) and A0535+26) were observed with the High Energy X ray Experiment (HEXE) onboard the Mir space station at energies above 20 keV. The pulse profiles of Vela X-1 (P = 283.22 s for JD 244 7486) and A0535+26 (P = 103.27 s for JD 244 7626) were measured up to at least 100 keV. The time averaged pulse profiles of the two sources both show a clear double peak structure with an asymmetric main pulse and a more symmetric secondary pulse. The spectrum of the main pulse is significantly harder than that of the secondary. Pulse phase resolved spectra show absorption features at 54 keV and possibly 27 keV for Vela X-1 and around 100 keV for A0535+26. If these features are interpreted as second and first harmonic (fundamental) cyclotron absorption lines, lower limits are derived of 2.6 x 10(exp 12) and 4.3 x 10(exp 12) Gauss for the magnetic fields of the neutron stars in Vela X-1 and A0535+26, respectively.

M ξ, M αβ, M γ and M m X-ray production cross-sections for elements with 71⩽ z⩽92 at 5.96 keV photon energy

NASA Astrophysics Data System (ADS)

Sharma, Manju; Sharma, Veena; Kumar, Sanjeev; Puri, S.; Singh, Nirmal

2006-11-01

The M ξ, M αβ, M γ and M m X-ray production (XRP) cross-sections have been measured for the elements with 71⩽ Z⩽92 at 5.96 keV incident photon energy satisfying EM1< Einc< EL3, where EM1(L3) is the M 1(L 3) subshell binding energy. These XRP cross-sections have been calculated using photoionization cross-sections based on the relativistic Dirac-Hartree-Slater (RDHS) model with three sets of X-ray emission rates, fluorescence, Coster-Kronig and super Coster-Kronig yields based on (i) the non-relativistic Hartree-Slater (NRHS) potential model, (ii) the RDHS model and (iii) the relativistic Dirac-Fock (RDF) model. For the third set, the M i ( i=1-5) subshell fluorescence yields have been calculated using the RDF model-based X-ray emission rates and total widths reevaluated to incorporate the RDF model-based radiative widths. The measured cross-sections have been compared with the calculated values to check the applicability of the physical parameters based on different models.

First NICER Observations of the Enigmatic Be Star, Gamma Cassiopeiae

NASA Astrophysics Data System (ADS)

Hamaguchi, Kenji; Drake, Stephen; Corcoran, Michael; Gendreau, Keith C.; Steiner, Jack; NICER team

2018-01-01

Gamma Cassiopeiae is an enigmatic Be star with unusually hard, strong X-ray emission compared with normal main-sequence B stars (but a much lower X-ray luminosity than the classic X-ray binaries). The X-ray characteristics - hot (kT ~12 keV), thermal plasma spectrum and rapid time variations on timescales of 10-1000 sec - is reminiscent of accreting compact objects. Alternatively, its shot-like rapid variations somewhat resemble solar-type magnetic reconnection flares, so that plasma heating by the star-disk magnetic dynamo of the Be star has been proposed. A recent discovery of rapid X-ray color variations with the Suzaku X-ray observatory revealed the presence of rapidly moving absorbers in the X-ray line of sight, giving a strong constraint on the geometry of the X-ray emitting regions and absorbers.The X-ray observatory onboard ISS, NICER, has observed Gamma Cas multiple times. The large collecting area in the 0.3-10 keV band, tolerance to photon pile-ups, and decent energy resolution in particular below 1 keV, should provide excellent pieces of information on how the X-ray emission and/or absorbing column change on short timescales. We will present the first result of the gamma Cas observations made by the NICER observatory.

Ethanol fixed brain imaging by phase-contrast X-ray technique

NASA Astrophysics Data System (ADS)

Takeda, Tohoru; Thet-Thet-Lwin; Kunii, Takuya; Sirai, Ryota; Ohizumi, Takahito; Maruyama, Hiroko; Hyodo, Kazuyuki; Yoneyama, Akio; Ueda, Kazuhiro

2013-03-01

The two-crystal phase-contrast X-ray imaging technique using an X-ray crystal interferometer can depict the fine structures of rat's brain such as cerebral cortex, white matter, and basal ganglia. Image quality and contrast by ethanol fixed brain showed significantly better than those by usually used formalin fixation at 35 keV X-ray energy. Image contrast of cortex by ethanol fixation was more than 3-times higher than that by formalin fixation. Thus, the technique of ethanol fixation might be better suited to image cerebral structural detail at 35 keV X-ray energy.

The MIT HEDP Accelerator Facility for Diagnostic Development for OMEGA, Z, and the NIF

NASA Astrophysics Data System (ADS)

Parker, C. E.; Gatu Johnson, M.; Birkel, A.; Kabadi, N. V.; Lahmann, B.; Milanese, L. M.; Simpson, R. A.; Sio, H.; Sutcliffe, G. D.; Wink, C.; Frenje, J. A.; Li, C. K.; Seguin, F. H.; Petrasso, R. D.; Leeper, R.; Ruiz, C. L.; Sangster, T. C.

2016-10-01

The MIT HEDP Accelerator Facility utilizes a 135-keV linear electrostatic ion accelerator, DT and DD neutron sources, and two x-ray sources for development and characterization of nuclear diagnostics for OMEGA, Z, and the NIF. The accelerator generates DD and D3He fusion products through the acceleration of D+ ions onto a 3He-doped Erbium-Deuteride target. Accurately characterized fusion product rates of around 106 s-1 are routinely achieved. The DT and DD neutron sources generate up to 6x108, and 1x107 neutrons/s, respectively. One x-ray generator is a thick-target W source with a peak energy of 225 keV and a maximum dose rate of 12 Gy/min; the other uses Cu, Mo, or Ti elemental tubes to generate x-rays with a maximum energy of 40 keV. Diagnostics developed and calibrated at this facility include CR-39-based charged-particle spectrometers, neutron detectors, and the particle Time-Of-Flight (pTOF) and Magnetic PTOF CVD-diamond-based bang time detectors. The accelerator is also a valuable hands-on tool for graduate and undergraduate education at MIT. This work was supported in part by the U.S. DoE, SNL, LLE and LLNL.

On-ground calibration of the ART-XC/SRG mirror system and detector unit at IKI. Part I

NASA Astrophysics Data System (ADS)

Pavlinsky, M.; Tkachenko, A.; Levin, V.; Krivchenko, A.; Rotin, A.; Kuznetsova, M.; Lapshov, I.; Krivonos, R.; Semena, A.; Semena, N.; Serbinov, D.; Shtykovsky, A.; Yaskovich, A.; Oleinikov, V.; Glushenko, A.; Mereminskiy, I.; Molkov, S.; Sazonov, S.; Arefiev, V.

2018-05-01

From October 2016 to September 2017, we performed tests of the ART-XC /SRG spare mirror system and detector unit at the 60-m-long IKI X-ray test facility. We describe some technical features of this test facility. We also present a brief description of the ART-XC mirror system and focal detectors. The nominal focal length of the ART-XC optics is 2700 mm. The field of view is determined by the combination of the mirror system and the detector unit and is equal to ˜0.31 square degrees. The declared operating energy range is 5-30 keV. During the tests, we illuminated the detector with a 55Fe+241 Am calibration source and also with a quasi-parallel X-ray beam. The calibration source is integrated into the detector's collimator. The X-ray beam was generated by a set of Oxford Instruments X-ray tubes with Cr, Cu and Mo targets and an Amptek miniature X-ray tube (Mini-X) with Ag transmission target. The detector was exposed to the X-ray beam either directly or through the mirror system. We present the obtained results on the detector's energy resolution, the muon on-ground background level and the energy dependence of the W90 value. The accuracy of a mathematical model of the ART-XC mirror system, based on ray-tracing simulations, proves to be within 3.5% in the main energy range of 4-20 keV and 5.4% in the "hard" energy range of 20-40 keV.

In situ flow cell for combined X-ray absorption spectroscopy, X-ray diffraction, and mass spectrometry at high photon energies under solar thermochemical looping conditions

NASA Astrophysics Data System (ADS)

Rothensteiner, Matthäus; Jenni, Joel; Emerich, Hermann; Bonk, Alexander; Vogt, Ulrich F.; van Bokhoven, Jeroen A.

2017-08-01

An in situ/operando flow cell for transmission mode X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), and combined XAS/XRD measurements in a single experiment under the extreme conditions of two-step solar thermochemical looping for the dissociation of water and/or carbon dioxide was developed. The apparatus exposes materials to relevant conditions of both the auto-reduction and the oxidation sub-steps of the thermochemical cycle at ambient temperature up to 1773 K and enables determination of the composition of the effluent gases by online quadrupole mass spectrometry. The cell is based on a tube-in-tube design and is heated by means of a focusing infrared furnace. It was tested successfully for carbon dioxide splitting. In combined XAS/XRD experiments with an unfocused beam, XAS measurements were performed at the Ce K edge (40.4 keV) and XRD measurements at 64.8 keV and 55.9 keV. Furthermore, XRD measurements with a focused beam at 41.5 keV were carried out. Equimolar ceria-hafnia was auto-reduced in a flow of argon and chemically reduced in a flow of hydrogen/helium. Under reducing conditions, all cerium(iv) was converted to cerium(iii) and a cation-ordered pyrochlore-type structure was formed, which was not stable upon oxidation in a flow of carbon dioxide.

In situ flow cell for combined X-ray absorption spectroscopy, X-ray diffraction, and mass spectrometry at high photon energies under solar thermochemical looping conditions.

PubMed

Rothensteiner, Matthäus; Jenni, Joel; Emerich, Hermann; Bonk, Alexander; Vogt, Ulrich F; van Bokhoven, Jeroen A

2017-08-01

An in situ/operando flow cell for transmission mode X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), and combined XAS/XRD measurements in a single experiment under the extreme conditions of two-step solar thermochemical looping for the dissociation of water and/or carbon dioxide was developed. The apparatus exposes materials to relevant conditions of both the auto-reduction and the oxidation sub-steps of the thermochemical cycle at ambient temperature up to 1773 K and enables determination of the composition of the effluent gases by online quadrupole mass spectrometry. The cell is based on a tube-in-tube design and is heated by means of a focusing infrared furnace. It was tested successfully for carbon dioxide splitting. In combined XAS/XRD experiments with an unfocused beam, XAS measurements were performed at the Ce K edge (40.4 keV) and XRD measurements at 64.8 keV and 55.9 keV. Furthermore, XRD measurements with a focused beam at 41.5 keV were carried out. Equimolar ceria-hafnia was auto-reduced in a flow of argon and chemically reduced in a flow of hydrogen/helium. Under reducing conditions, all cerium(iv) was converted to cerium(iii) and a cation-ordered pyrochlore-type structure was formed, which was not stable upon oxidation in a flow of carbon dioxide.

ETA CARINAE’S THERMAL X-RAY TAIL MEASURED WITH XMM-NEWTON AND NuSTAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamaguchi, Kenji; Corcoran, Michael F.; Gull, Theodore R.

The evolved, massive highly eccentric binary system, η Car, underwent a periastron passage in the summer of 2014. We obtained two coordinated X-ray observations with XMM-Newton and NuSTAR during the elevated X-ray flux state and just before the X-ray minimum flux state around this passage. 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. This temperature is ΔkT ∼ 2 keV higher than those measured from the iron K emission line complex, if the shockedmore » gas is in collisional ionization equilibrium. 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 X-ray emission by 40% at energies above 5 keV in a day, the largest rate of change of the X-ray flux yet observed in individual η Car observations. The column density to the hardest emission component, N{sub H} ∼ 10{sup 24} H cm{sup −2}, marked one of the highest values ever observed for η Car, strongly suggesting increased obscuration of the wind–wind colliding 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 wind–wind collision apex. Alternatively, it may be that the power-law source is not related to either η Car or the GeV γ-ray source.« less

Energy distribution measurement of narrow-band ultrashort x-ray beams via K-edge filters subtraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cardarelli, Paolo; Di Domenico, Giovanni; Marziani, Michele

2012-10-01

The characterization of novel x-ray sources includes the measurement of the photon flux and the energy distribution of the produced beam. The aim of BEATS2 experiment at the SPARC-LAB facility of the INFN National Laboratories of Frascati (Rome, Italy) is to investigate possible medical applications of an x-ray source based on Thomson relativistic back-scattering. This source is expected to produce a pulsed quasi-monochromatic x-ray beam with an instantaneous flux of 10{sup 20} ph/s in pulses 10 ps long and with an average energy of about 20 keV. A direct measurement of energy distribution of this beam is very difficult withmore » traditional detectors because of the extremely high photon flux. In this paper, we present a method for the evaluation of the energy distribution of quasi-monochromatic x-ray beams based on beam filtration with K-edge absorbing foils in the energy range of interest (16-22 keV). The technique was tested measuring the energy distribution of an x-ray beam having a spectrum similar to the expected one (SPARC-LAB Thomson source) by using a tungsten anode x-ray tube properly filtered and powered. The energy distribution obtained has been compared with the one measured with a HPGe detector showing very good agreement.« less

Fabrication process for a gradient index x-ray lens

DOEpatents

Bionta, R.M.; Makowiecki, D.M.; Skulina, K.M.

1995-01-17

A process is disclosed for fabricating high efficiency x-ray lenses that operate in the 0.5-4.0 keV region suitable for use in biological imaging, surface science, and x-ray lithography of integrated circuits. The gradient index x-ray optics fabrication process broadly involves co-sputtering multi-layers of film on a wire, followed by slicing and mounting on block, and then ion beam thinning to a thickness determined by periodic testing for efficiency. The process enables the fabrication of transmissive gradient index x-ray optics for the 0.5-4.0 keV energy range. This process allows the fabrication of optical elements for the next generation of imaging and x-ray lithography instruments in the soft x-ray region. 13 figures.

Fabrication process for a gradient index x-ray lens

DOEpatents

Bionta, Richard M.; Makowiecki, Daniel M.; Skulina, Kenneth M.

1995-01-01

A process for fabricating high efficiency x-ray lenses that operate in the 0.5-4.0 keV region suitable for use in biological imaging, surface science, and x-ray lithography of integrated circuits. The gradient index x-ray optics fabrication process broadly involves co-sputtering multi-layers of film on a wire, followed by slicing and mounting on block, and then ion beam thinning to a thickness determined by periodic testing for efficiency. The process enables the fabrication of transmissive gradient index x-ray optics for the 0.5-4.0 keV energy range. This process allows the fabrication of optical elements for the next generation of imaging and x-ray lithography instruments m the soft x-ray region.

The Hitomi (ASTRO-H) Soft X-ray Telescope (SXT): current status of calibration

NASA Astrophysics Data System (ADS)

Maeda, Yoshitomo; Kikuchi, Naomichi; Kurashima, Sho; Ishida, Manabu; Iizuka, Ryo; Hayashi, Takayuki; Okajima, Takashi; Matsumoto, Hironori; Mitsuishi, Ikuyuki; Saji, Shigetaka; Sato, Toshiki; Tachibana, Sasagu; Mori, Hideyuki; Christensen, Finn; Brejnholt, Nicolai; Nitta, Kiyofumi; Uruga, Tomoya

2017-08-01

We report the atomic scattering factor in the 11.2-15.4 keV for the ASTRO-H Soft X-ray Telescope (SXT)9 obtained in the ground based measurements. The large effective area of the SXT covers above 10 keV. In fact, the flight data show the spectra of the celestical objects in the hard X-ray band. In order to model the area, the reflectivity measurements in the 11.2-15.4 keV band with the energy pitch of 0.4 - 0.7 eV were made in the synchrotron beamline Spring-8 BL01B1. We obtained atomic scattering factors f1 and f2 by the curve fitting to the reflectivities of our witness sample. The edges associated with the gold' s L-I, II, and III transitions are identified, of which the depths are found to be roughly 60% shallower than those expected from the Henke's atomic scattering factor.

Development of Ni-based multilayers for future focusing soft gamma ray telescopes

NASA Astrophysics Data System (ADS)

Girou, David A.; Massahi, Sonny; Sleire, Erlend K.; Jakobsen, Anders C.; Christensen, Finn E.

2015-09-01

Ni-based multilayers are a possible solution to extend the upper energy range of hard X-ray focusing telescopes currently limited at ≈79:4 keV by the Pt-K absorption edge. In this study 10 bilayers multilayers with a constant bilayer thickness were coated with the DC magnetron sputtering facility at DTU Space, characterized at 8 keV using X-ray reectometry and fitted using the IMD software. Ni/C multilayers were found to have a mean interface roughness ≈ 1:5 times lower than Ni/B4C multilayers. Reactive sputtering with ≈ 76% of Ar and ≈ 24% of N2 reduced the mean interface roughness by a factor of ≈ 1:7. It also increased the coating rate of C by a factor of ≈ 3:1 and lead to a coating process going ≈ 1:6 times faster. Honeycomb collimation proved to limit the increase in mean interface roughness when the bilayer thickness increases at the price of a coating process going ≈ 1:9 times longer than with separator plates. Finally a Ni/C 150 bilayers depth-graded mutilayer was coated with reactive sputtering and honeycomb collimation and then characterized from 10 keV to 150 keV. It showed 10% reectance up to 85 keV.

Hard X-ray Emission from the M87 AGN Detected with NuSTAR

NASA Astrophysics Data System (ADS)

Wong, Ka-Wah; Nemmen, Rodrigo; Irwin, Jimmy; Lin, Dacheng

2018-01-01

M87 hosts a 3–6 billion solar mass black hole with a remarkable relativistic jet that has been regularly monitored in radio to TeV bands. However, hard X-ray emission above 10keV expected to primarily come from the jet or the accretion flow had never been detected from its unresolved X-ray core. We report NuSTAR detection up to 40 keV from the the central regions of M87. Together with simultaneous Chandra observations, we have constrained the dominant hard X-ray emission to be from its unresolved X-ray core, presumably in its quiescent state. The core spectrum is well fitted by a power-law. The measured flux density at 40keV is consistent with a jet origin, although emission from the advection-dominated accretion flow cannot be completely ruled out. The detected hard X-ray emission is significantly lower than that predicted by synchrotron self-Compton models introduced to explain emission above a GeV.

Performance of the PRAXyS X-Ray Polarimeter

NASA Technical Reports Server (NTRS)

Iwakiri, W. B.; Black, J. K.; Cole, R.; Enoto, T.; Hayato, A.; Hill, J. E.; Jahoda, Keith M.; Kaaret, P.; Kitaguchi, T.; Kubota, M.

2016-01-01

The performance of the Time Projection Chamber (TPC) polarimeter for the Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) Small Explorer was evaluated using polarized and unpolarized X-ray sources. The PRAXyS mission will enable exploration of the universe through X-ray polarimetry in the 2-10 keV energy band. We carried out performance tests of the polarimeter at the Brookhaven National Laboratory, National Synchrotron Light Source (BNL-NSLS) and at NASA's Goddard Space Flight Center. The polarimeter was tested with linearly polarized, monochromatic X-rays at 11 different energies between 2.5 and 8.0 keV. At maximum sensitivity, the measured modulation factors at 2.7, 4.5 and 8.0 keV are 27%, 43% and 59%, respectively and the measured angle of polarization is consistent with the expected value at all energies. Measurements with a broadband, unpolarized X-ray source placed a limit of less than 1% on false polarization in the PRAXyS polarimeter.

Performance of the PRAXyS X-ray polarimeter

NASA Astrophysics Data System (ADS)

Iwakiri, W. B.; Black, J. K.; Cole, R.; Enoto, T.; Hayato, A.; Hill, J. E.; Jahoda, K.; Kaaret, P.; Kitaguchi, T.; Kubota, M.; Marlowe, H.; McCurdy, R.; Takeuchi, Y.; Tamagawa, T.

2016-12-01

The performance of the Time Projection Chamber (TPC) polarimeter for the Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) Small Explorer was evaluated using polarized and unpolarized X-ray sources. The PRAXyS mission will enable exploration of the universe through X-ray polarimetry in the 2-10 keV energy band. We carried out performance tests of the polarimeter at the Brookhaven National Laboratory, National Synchrotron Light Source (BNL-NSLS) and at NASA's Goddard Space Flight Center. The polarimeter was tested with linearly polarized, monochromatic X-rays at 11 different energies between 2.5 and 8.0 keV. At maximum sensitivity, the measured modulation factors at 2.7, 4.5 and 8.0 keV are 27%, 43% and 59%, respectively and the measured angle of polarization is consistent with the expected value at all energies. Measurements with a broadband, unpolarized X-ray source placed a limit of less than 1% on false polarization in the PRAXyS polarimeter.

Sub-second variations of high energy ( 300 keV) hard X-ray emission from solar flares

NASA Technical Reports Server (NTRS)

Bai, Taeil

1986-01-01

Subsecond variations of hard X-ray emission from solar flares were first observed with a balloon-borne detector. With the launch of the Solar Maximum Mission (SMM), it is now well known that subsecond variations of hard X-ray emission occur quite frequently. Such rapid variations give constraints on the modeling of electron energization. Such rapid variations reported until now, however, were observed at relatively low energies. Fast mode data obtained by the Hard X-ray Burst Spectrometer (HXRBS) has time resolution of approximately 1 ms but has no energy resolution. Therefore, rapid fluctuations observed in the fast-mode HXRBS data are dominated by the low energy hard X-rays. It is of interest to know whether rapid fluctuations are observed in high-energy X-rays. The highest energy band at which subsecond variations were observed is 223 to 1057 keV. Subsecond variations observed with HXRBS at energies greater than 300 keV are reported, and the implications discussed.

Soft X-ray maps of the Large Magellanic Cloud (LMC)

NASA Technical Reports Server (NTRS)

Singh, K. P.; Nousek, J. A.; Burrows, D. N.; Garmire, G. P.

1985-01-01

Soft X-ray maps of the Large Magellanic Cloud (LMC) were obtained from scanning-observations with the HEAO-1 low energy detectors. Comparison of the 1/4 keV X-ray observations with the neutral hydrogen column densities in the LMC obtained from a 21 cm line survey, shows no evidence for absorption effects in the 1/4 keV X-ray flux from the LMC due to the neutral matter in the LMC. Instead, faint X-ray emission is detected from the LMC. The extent of this emission is smaller than the size of the halo or the disk of the LMC. Assuming this 1/4 keV emission to be diffuse, it is identified with a supergiant shell of optical nebulosity known as Shapley III, and the bar of the LMC. The X-ray luminosities of the regions are estimated to be 9 times 10 to the 38th power ergs/sec and 1.8 times 10 to the 39th power ergs/sec for the Shapley III region and the bar of the LMC respectively. Shapley III could be an X-ray superbubble.

Ground Laboratory Soft X-Ray Durability Evaluation of Aluminized Teflon FEP Thermal Control Insulation

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; deGroh, Kim K.; Stueber, Thomas J.; Sechkar, Edward A.

1998-01-01

Metallized Teflon fluorinated ethylene propylene (FEP) thermal control insulation is mechanically degraded if exposed to a sufficient fluence of soft x-ray radiation. Soft x-ray photons (4-8 A in wavelength or 1.55 - 3.2 keV) emitted during solar flares have been proposed as a cause of mechanical properties degradation of aluminized Teflon FEP thermal control insulation on the Hubble Space Telescope (HST). Such degradation can be characterized by a reduction in elongation-to-failure of the Teflon FER Ground laboratory soft x-ray exposure tests of aluminized Teflon FEP were conducted to assess the degree of elongation degradation which would occur as a result of exposure to soft x-rays in the range of 3-10 keV. Tests results indicate that soft x-ray exposure in the 3-10 keV range, at mission fluence levels, does not alone cause the observed reduction in elongation of flight retrieved samples. The soft x-ray exposure facility design, mechanical properties degradation results and implications will be presented.

Ground Laboratory Soft X-Ray Durability Evaluation of Aluminized Teflon FEP Thermal Control Insulation. Revised

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; deGroh, Kim K.; Stueber, Thomas J.; Sechkar, Edward A.; Hall, Rachelle L.

1998-01-01

Metallized Teflon fluorinated ethylene propylene (FEP) thermal control insulation is mechanically degraded if exposed to a sufficient fluence of soft x-ray radiation. Soft x-ray photons (4-8 A in wavelength or 1.55 - 3.2 keV) emitted during solar flares have been proposed as a cause of mechanical properties degradation of aluminized Teflon FEP thermal control insulation on the Hubble Space Telescope (HST). Such degradation can be characterized by a reduction in elongation-to-failure of the Teflon FEP. Ground laboratory soft x-ray exposure tests of aluminized Teflon FEP were conducted to assess the degree of elongation degradation which would occur as a result of exposure to soft x-rays in the range of 3-10 keV. Tests results indicate that soft x-ray exposure in the 3-10 keV range, at mission fluence levels, does not alone cause the observed reduction in elongation of flight retrieved samples. The soft x-ray exposure facility design, mechanical properties degradation results and implications will be presented.

A NuSTAR Observation of the Gamma-Ray Emitting Millisecond Pulsar PSR J1723–2837

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kong, A. K. H.; Hui, C. Y.; Takata, J.

We report on the first NuSTAR observation of the gamma-ray emitting millisecond pulsar binary PSR J1723–2837. X-ray radiation up to 79 keV is clearly detected, and the simultaneous NuSTAR and Swift spectrum is well described by an absorbed power law with a photon index of ∼1.3. We also find X-ray modulations in the 3–10, 10–20, 20–79, and 3–79 keV bands at the 14.8 hr binary orbital period. All of these are entirely consistent with previous X-ray observations below 10 keV. This new hard X-ray observation of PSR J1723–2837 provides strong evidence that the X-rays are from the intrabinary shock viamore » an interaction between the pulsar wind and the outflow from the companion star. We discuss how the NuSTAR observation constrains the physical parameters of the intrabinary shock model.« less

Absolute x-ray energy calibration and monitoring using a diffraction-based method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, Xinguo, E-mail: xhong@bnl.gov; Weidner, Donald J.; Duffy, Thomas S.

2016-07-27

In this paper, we report some recent developments of the diffraction-based absolute X-ray energy calibration method. In this calibration method, high spatial resolution of the measured detector offset is essential. To this end, a remotely controlled long-translation motorized stage was employed instead of the less convenient gauge blocks. It is found that the precision of absolute X-ray energy calibration (ΔE/E) is readily achieved down to the level of 10{sup −4} for high-energy monochromatic X-rays (e.g. 80 keV). Examples of applications to pair distribution function (PDF) measurements and energy monitoring for high-energy X-rays are presented.

First Hard X-Ray Detection of the Non-Thermal Emission Around the Arches Cluster: Morphology and Spectral Studies With NuSTAR

NASA Technical Reports Server (NTRS)

Krivonos, Roman A.; Tomsick, John A.; Bauer, Franz E.; Baganoff, Frederick K.; Barriere, Nicolas M.; Bodaghee, Arash; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Grefenstette, Brian W.;

Swift/BAT Detects Increase in Hard X-ray Emission from the Ultra-compact X-ray Binary 4U 1543-624

NASA Astrophysics Data System (ADS)

Ludlam, Renee; Miller, Jon M.; Miller-Jones, James; Reynolds, Mark

2017-08-01

The Swift/BAT detected an increase in hard X-ray emission (15-50 keV) coming from the ultra-compact X-ray binary 4U 1543-624 around 2017 August 9. The MAXI daily monitoring also shows a gradual increase in 2.0-20.0 keV X-ray intensity as of 2017 August 19. Swift/XRT ToO monitoring of the source was triggered and shows an increase in unabsorbed flux to 1.06E-9 ergs/cm2/s in the 0.3-10.0 keV energy band as of 2017 August 26. ATCA performed ToO observations for approximately 4 hours in the 5.5 GHz and 9.0 GHz bands while the antennas were in the 1.5A array configuration from 11:25-16:09 UTC on 2017 August 23. The source was not detected in either band.

The Hard X-ray 20-40 keV AGN Luminosity Function

NASA Technical Reports Server (NTRS)

Beckmann, V.; Soldi, S.; Shrader, C. R.; Gehrels, N.; Produit, N.

2006-01-01

We have compiled a complete, significance limited extragalactic sample based on approximately 25,000 deg(sup 2) to a limiting flux of 3 x 10(exp -11) ergs per square centimeter per second. (approximately 7,000 deg(sup 2)) to a flux limit of 10(exp -11) ergs per square centimeter per second)) in the 20 - 40 keV band with INTEGRAL. We have constructed a detailed exposure map to compensate for effects of non-uniform exposure. The flux-number relation is best described by a power-law with a slope of alpha = 1.66 plus or minus 0.11. The integration of the cumulative flux per unit area leads to f(sub 20-40 keV) = 2.6 x 10(exp -10) ergs per square centimeter per second per sr(sup -1) which is about 1% of the known 20-40 keV X-ray background. We present the first luminosity function of AGN in the 20-40 keV energy range, based on 68 extragalactic objects detected by the imager IBIS/ISGRI on-board INTEGRAL. The luminosity function shows a smoothly connected two power-law form, with an index of gamma (sub 1) = 0.9 below, and gamma (sub 2) = 2.2 above the turn-over luminosity of L(sub *), = 4.6 x 10(sup 43) ergs per second. The emissivity of all INTEGRAL AGNs per unit volume is W(sub 20-40keV)(greater than 10(sup 41) ergs per second) = 2.8 x 10(sup 38) ergs per second h(sup 3)(sub 70) Mpc(sup -3). These results are consistent with those derived in the 2-20keV energy band and do not show a significant contribution by Compton-thick objects. Because the sample used in this study is truly local (z(raised bar) = 0.022)), only limited conclusions can be drawn for the evolution of AGNs in this energy band. But the objects explaining the peak in the cosmic X-ray background are likely to be either low luminosity AGN (L(sub x) less than 10(sup 41) ergs per second) or of other type, such as intermediate mass black holes, clusters, and star forming regions.

A 7.2 keV spherical x-ray crystal backlighter for two-frame, two-color backlighting at Sandia's Z Pulsed Power Facility

NASA Astrophysics Data System (ADS)

Schollmeier, M. S.; Knapp, P. F.; Ampleford, D. J.; Harding, E. C.; Jennings, C. A.; Lamppa, D. C.; Loisel, G. P.; Martin, M. R.; Robertson, G. K.; Shores, J. E.; Smith, I. C.; Speas, C. S.; Weis, M. R.; Porter, J. L.; McBride, R. D.

2017-10-01

Many experiments on Sandia National Laboratories' Z Pulsed Power Facility—a 30 MA, 100 ns rise-time, pulsed-power driver—use a monochromatic quartz crystal backlighter system at 1.865 keV (Si He α ) or 6.151 keV (Mn He α ) x-ray energy to radiograph an imploding liner (cylindrical tube) or wire array z-pinch. The x-ray source is generated by the Z-Beamlet laser, which provides two 527-nm, 1 kJ, 1-ns laser pulses. Radiographs of imploding, thick-walled beryllium liners at convergence ratios CR above 15 [ C R = r i ( 0 ) / r i ( t ) ] using the 6.151-keV backlighter system were too opaque to identify the inner radius r i of the liner with high confidence, demonstrating the need for a higher-energy x-ray radiography system. Here, we present a 7.242 keV backlighter system using a Ge(335) spherical crystal with the Co He α resonance line. This system operates at a similar Bragg angle as the existing 1.865 keV and 6.151 keV backlighters, enhancing our capabilities for two-color, two-frame radiography without modifying the system integration at Z. The first data taken at Z include 6.2-keV and 7.2-keV two-color radiographs as well as radiographs of low-convergence (CR about 4-5), high-areal-density liner implosions.

A 7.2 keV spherical x-ray crystal backlighter for two-frame, two-color backlighting at Sandia’s Z Pulsed Power Facility

DOE PAGES

Schollmeier, M. S.; Knapp, P. F.; Ampleford, D. J.; ...

2017-10-10

Many experiments on Sandia National Laboratories’ Z Pulsed Power Facility—a 30 MA, 100 ns rise-time, pulsed-power driver—use a monochromatic quartz crystal backlighter system at 1.865 keV (Si He α) or 6.151 keV (Mn He α) x-ray energy to radiograph an imploding liner (cylindrical tube) or wire array z-pinch. The x-ray source is generated by the Z-Beamlet laser, which provides two 527-nm, 1 kJ, 1-ns laser pulses. Radiographs of imploding, thick-walled beryllium liners at convergence ratios C R above 15 [C R=r i(0)/r i(t)] using the 6.151-keV backlighter system were too opaque to identify the inner radius ri of the linermore » with high confidence, demonstrating the need for a higher-energy x-ray radiography system. Here, we present a 7.242 keV backlighter system using a Ge(335) spherical crystal with the Co He α resonance line. This system operates at a similar Bragg angle as the existing 1.865 keV and 6.151 keV backlighters, enhancing our capabilities for two-color, two-frame radiography without modifying the system integration at Z. The first data taken at Z include 6.2-keV and 7.2-keV two-color radiographs as well as radiographs of low-convergence (C R about 4-5), high-areal-density liner implosions.« less

A 7.2 keV spherical x-ray crystal backlighter for two-frame, two-color backlighting at Sandia’s Z Pulsed Power Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schollmeier, M. S.; Knapp, P. F.; Ampleford, D. J.

Many experiments on Sandia National Laboratories’ Z Pulsed Power Facility—a 30 MA, 100 ns rise-time, pulsed-power driver—use a monochromatic quartz crystal backlighter system at 1.865 keV (Si He α) or 6.151 keV (Mn He α) x-ray energy to radiograph an imploding liner (cylindrical tube) or wire array z-pinch. The x-ray source is generated by the Z-Beamlet laser, which provides two 527-nm, 1 kJ, 1-ns laser pulses. Radiographs of imploding, thick-walled beryllium liners at convergence ratios C R above 15 [C R=r i(0)/r i(t)] using the 6.151-keV backlighter system were too opaque to identify the inner radius ri of the linermore » with high confidence, demonstrating the need for a higher-energy x-ray radiography system. Here, we present a 7.242 keV backlighter system using a Ge(335) spherical crystal with the Co He α resonance line. This system operates at a similar Bragg angle as the existing 1.865 keV and 6.151 keV backlighters, enhancing our capabilities for two-color, two-frame radiography without modifying the system integration at Z. The first data taken at Z include 6.2-keV and 7.2-keV two-color radiographs as well as radiographs of low-convergence (C R about 4-5), high-areal-density liner implosions.« less

Energy dependent features of X-ray signals in a GridPix detector

NASA Astrophysics Data System (ADS)

Krieger, C.; Kaminski, J.; Vafeiadis, T.; Desch, K.

2018-06-01

We report on the calibration of an argon/isobutane (97.7%/2.3%)-filled GridPix detector with soft X-rays (277 eV to 8 keV) using the variable energy X-ray source of the CAST Detector Lab at CERN. We study the linearity and energy resolution of the detector using both the number of pixels hit and the total measured charge as energy measures. For the latter, the energy resolution σE / E is better than 10% (20%) for energies above 2 keV (0.5 keV). Several characteristics of the recorded events are studied.

The soft X-ray diffuse background observed with the HEAO 1 low-energy detectors

NASA Technical Reports Server (NTRS)

Garmire, G. P.; Nousek, J. A.; Apparao, K. M. V.; Burrows, D. N.; Fink, R. L.; Kraft, R. P.

1992-01-01

Results of a study of the diffuse soft-X-ray background as observed by the low-energy detectors of the A-2 experiment aboard the HEAO 1 satellite are reported. The observed sky intensities are presented as maps of the diffuse X-ray background sky in several energy bands covering the energy range 0.15-2.8 keV. It is found that the soft X-ray diffuse background (SXDB) between 1.5 and 2.8 keV, assuming a power law form with photon number index 1.4, has a normalization constant of 10.5 +/- 1.0 photons/sq cm s sr keV. Below 1.5 keV the spectrum of the SXDB exceeds the extrapolation of this power law. The low-energy excess for the NEP can be fitted with emission from a two-temperature equilibrium plasma model with the temperatures given by log I1 = 6.16 and log T2 = 6.33. It is found that this model is able to account for the spectrum below 1 keV, but fails to yield the observed Galactic latitude variation.

Extended observations of higher than 7-keV X-rays from Centaurus X-3 by the OSO-7 satellite

NASA Technical Reports Server (NTRS)

Baity, W. A.; Ulmer, M. P.; Wheaton, W. A.; Peterson, L. E.

1974-01-01

The UCSD X-ray telescope on board OSO-7 provided 43 days of continuous coverage of the variable X-ray source Cen X-3 at energies above 7 keV during December 1971 and January 1972. We detected the 4.8-sec pulsation period, the 2.087-day eclipse cycle, and an apparently nonperiodic, low-intensity state lasting more than 12 days. Spectra obtained over the 7-30 keV range during noneclipsed high-intensity states are steeper than those previously reported. Large changes, which may be characterized by a number spectral index alpha varying between 3.0 plus or minus 0.2 and 2.0 plus or minus 0.3, or by exponential spectra with kT varying from 6 plus or minus 2 to 13 plus or minus 3 keV, occur at different high-intensity states.

Hitomi X-ray observation of the pulsar wind nebula G21.5-0.9

NASA Astrophysics Data System (ADS)

Aharonian, Felix; Akamatsu, Hiroki; Akimoto, Fumie; Allen, Steven W.; Angelini, Lorella; Audard, Marc; Awaki, Hisamitsu; Axelsson, Magnus; Bamba, Aya; Bautz, Marshall W.; Blandford, Roger; Brenneman, Laura W.; Brown, Gregory V.; Bulbul, Esra; Cackett, Edward M.; Chernyakova, Maria; Chiao, Meng P.; Coppi, Paolo S.; Costantini, Elisa; de Plaa, Jelle; de Vries, Cor P.; den Herder, Jan-Willem; Done, Chris; Dotani, Tadayasu; Ebisawa, Ken; Eckart, Megan E.; Enoto, Teruaki; Ezoe, Yuichiro; Fabian, Andrew C.; Ferrigno, Carlo; Foster, Adam R.; Fujimoto, Ryuichi; Fukazawa, Yasushi; Furuzawa, Akihiro; Galeazzi, Massimiliano; Gallo, Luigi C.; Gandhi, Poshak; Giustini, Margherita; Goldwurm, Andrea; Gu, Liyi; Guainazzi, Matteo; Haba, Yoshito; Hagino, Kouichi; Hamaguchi, Kenji; Harrus, Ilana M.; Hatsukade, Isamu; Hayashi, Katsuhiro; Hayashi, Takayuki; Hayashida, Kiyoshi; Hiraga, Junko S.; Hornschemeier, Ann; Hoshino, Akio; Hughes, John P.; Ichinohe, Yuto; Iizuka, Ryo; Inoue, Hajime; Inoue, Yoshiyuki; Ishida, Manabu; Ishikawa, Kumi; Ishisaki, Yoshitaka; Iwai, Masachika; Kaastra, Jelle; Kallman, Tim; Kamae, Tsuneyoshi; Kataoka, Jun; Katsuda, Satoru; Kawai, Nobuyuki; Kelley, Richard L.; Kilbourne, Caroline A.; Kitaguchi, Takao; Kitamoto, Shunji; Kitayama, Tetsu; Kohmura, Takayoshi; Kokubun, Motohide; Koyama, Katsuji; Koyama, Shu; Kretschmar, Peter; Krimm, Hans A.; Kubota, Aya; Kunieda, Hideyo; Laurent, Philippe; Lee, Shiu-Hang; Leutenegger, Maurice A.; Limousin, Olivier; Loewenstein, Michael; Long, Knox S.; Lumb, David; Madejski, Greg; Maeda, Yoshitomo; Maier, Daniel; Makishima, Kazuo; Markevitch, Maxim; Matsumoto, Hironori; Matsushita, Kyoko; McCammon, Dan; McNamara, Brian R.; Mehdipour, Missagh; Miller, Eric D.; Miller, Jon M.; Mineshige, Shin; Mitsuda, Kazuhisa; Mitsuishi, Ikuyuki; Miyazawa, Takuya; Mizuno, Tsunefumi; Mori, Hideyuki; Mori, Koji; Mukai, Koji; Murakami, Hiroshi; Mushotzky, Richard F.; Nakagawa, Takao; Nakajima, Hiroshi; Nakamori, Takeshi; Nakashima, Shinya; Nakazawa, Kazuhiro; Nobukawa, Kumiko K.; Nobukawa, Masayoshi; Noda, Hirofumi; Odaka, Hirokazu; Ohashi, Takaya; Ohno, Masanori; Okajima, Takashi; Ota, Naomi; Ozaki, Masanobu; Paerels, Frits; Paltani, Stéphane; Petre, Robert; Pinto, Ciro; Porter, Frederick S.; Pottschmidt, Katja; Reynolds, Christopher S.; Safi-Harb, Samar; Saito, Shinya; Sakai, Kazuhiro; Sasaki, Toru; Sato, Goro; Sato, Kosuke; Sato, Rie; Sawada, Makoto; Schartel, Norbert; Serlemtsos, Peter J.; Seta, Hiromi; Shidatsu, Megumi; Simionescu, Aurora; Smith, Randall K.; Soong, Yang; Stawarz, Łukasz; Sugawara, Yasuharu; Sugita, Satoshi; Szymkowiak, Andrew; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shin'ichiro; Takei, Yoh; Tamagawa, Toru; Tamura, Takayuki; Tanaka, Takaaki; Tanaka, Yasuo; Tanaka, Yasuyuki T.; Tashiro, Makoto S.; Tawara, Yuzuru; Terada, Yukikatsu; Terashima, Yuichi; Tombesi, Francesco; Tomida, Hiroshi; Tsuboi, Yohko; Tsujimoto, Masahiro; Tsunemi, Hiroshi; Tsuru, Takeshi Go; Uchida, Hiroyuki; Uchiyama, Hideki; Uchiyama, Yasunobu; Ueda, Shutaro; Ueda, Yoshihiro; Uno, Shin'ichiro; Urry, C. Megan; Ursino, Eugenio; Watanabe, Shin; Werner, Norbert; Wilkins, Dan R.; Williams, Brian J.; Yamada, Shinya; Yamaguchi, Hiroya; Yamaoka, Kazutaka; Yamasaki, Noriko Y.; Yamauchi, Makoto; Yamauchi, Shigeo; Yaqoob, Tahir; Yatsu, Yoichi; Yonetoku, Daisuke; Zhuravleva, Irina; Zoghbi, Abderahmen; Sato, Toshiki; Nakaniwa, Nozomu; Murakami, Hiroaki; Guest, Benson

2018-04-01

We present results from the Hitomi X-ray observation of a young composite-type supernova remnant (SNR) G21.5-0.9, whose emission is dominated by the pulsar wind nebula (PWN) contribution. The X-ray spectra in the 0.8-80 keV range obtained with the Soft X-ray Spectrometer (SXS), Soft X-ray Imager, and Hard X-ray Imager (HXI) show a significant break in the continuum as previously found with the NuSTAR observation. After taking into account all known emissions from the SNR other than the PWN itself, we find that the Hitomi spectra can be fitted with a broken power law with photon indices of Γ1 = 1.74 ± 0.02 and Γ2 = 2.14 ± 0.01 below and above the break at 7.1 ± 0.3 keV, which is significantly lower than the NuSTAR result (˜9.0 keV). The spectral break cannot be reproduced by time-dependent particle injection one-zone spectral energy distribution models, which strongly indicates that a more complex emission model is needed, as suggested by recent theoretical models. We also search for narrow emission or absorption lines with the SXS, and perform a timing analysis of PSR J1833-1034 with the HXI and the Soft Gamma-ray Detector. No significant pulsation is found from the pulsar. However, unexpectedly, narrow absorption line features are detected in the SXS data at 4.2345 keV and 9.296 keV with a significance of 3.65 σ. While the origin of these features is not understood, their mere detection opens up a new field of research and was only possible with the high resolution, sensitivity, and ability to measure extended sources provided by an X-ray microcalorimeter.

Hitomi X-ray observation of the pulsar wind nebula G21.5-0.9

NASA Astrophysics Data System (ADS)

Hitomi Collaboration; Aharonian, Felix; Akamatsu, Hiroki; Akimoto, Fumie; Allen, Steven W.; Angelini, Lorella; Audard, Marc; Awaki, Hisamitsu; Axelsson, Magnus; Bamba, Aya; Bautz, Marshall W.; Blandford, Roger; Brenneman, Laura W.; Brown, Gregory V.; Bulbul, Esra; Cackett, Edward M.; Chernyakova, Maria; Chiao, Meng P.; Coppi, Paolo S.; Costantini, Elisa; de Plaa, Jelle; de Vries, Cor P.; den Herder, Jan-Willem; Done, Chris; Dotani, Tadayasu; Ebisawa, Ken; Eckart, Megan E.; Enoto, Teruaki; Ezoe, Yuichiro; Fabian, Andrew C.; Ferrigno, Carlo; Foster, Adam R.; Fujimoto, Ryuichi; Fukazawa, Yasushi; Furuzawa, Akihiro; Galeazzi, Massimiliano; Gallo, Luigi C.; Gandhi, Poshak; Giustini, Margherita; Goldwurm, Andrea; Gu, Liyi; Guainazzi, Matteo; Haba, Yoshito; Hagino, Kouichi; Hamaguchi, Kenji; Harrus, Ilana M.; Hatsukade, Isamu; Hayashi, Katsuhiro; Hayashi, Takayuki; Hayashida, Kiyoshi; Hiraga, Junko S.; Hornschemeier, Ann; Hoshino, Akio; Hughes, John P.; Ichinohe, Yuto; Iizuka, Ryo; Inoue, Hajime; Inoue, Yoshiyuki; Ishida, Manabu; Ishikawa, Kumi; Ishisaki, Yoshitaka; Iwai, Masachika; Kaastra, Jelle; Kallman, Tim; Kamae, Tsuneyoshi; Kataoka, Jun; Katsuda, Satoru; Kawai, Nobuyuki; Kelley, Richard L.; Kilbourne, Caroline A.; Kitaguchi, Takao; Kitamoto, Shunji; Kitayama, Tetsu; Kohmura, Takayoshi; Kokubun, Motohide; Koyama, Katsuji; Koyama, Shu; Kretschmar, Peter; Krimm, Hans A.; Kubota, Aya; Kunieda, Hideyo; Laurent, Philippe; Lee, Shiu-Hang; Leutenegger, Maurice A.; Limousin, Olivier; Loewenstein, Michael; Long, Knox S.; Lumb, David; Madejski, Greg; Maeda, Yoshitomo; Maier, Daniel; Makishima, Kazuo; Markevitch, Maxim; Matsumoto, Hironori; Matsushita, Kyoko; McCammon, Dan; McNamara, Brian R.; Mehdipour, Missagh; Miller, Eric D.; Miller, Jon M.; Mineshige, Shin; Mitsuda, Kazuhisa; Mitsuishi, Ikuyuki; Miyazawa, Takuya; Mizuno, Tsunefumi; Mori, Hideyuki; Mori, Koji; Mukai, Koji; Murakami, Hiroshi; Mushotzky, Richard F.; Nakagawa, Takao; Nakajima, Hiroshi; Nakamori, Takeshi; Nakashima, Shinya; Nakazawa, Kazuhiro; Nobukawa, Kumiko K.; Nobukawa, Masayoshi; Noda, Hirofumi; Odaka, Hirokazu; Ohashi, Takaya; Ohno, Masanori; Okajima, Takashi; Ota, Naomi; Ozaki, Masanobu; Paerels, Frits; Paltani, Stéphane; Petre, Robert; Pinto, Ciro; Porter, Frederick S.; Pottschmidt, Katja; Reynolds, Christopher S.; Safi-Harb, Samar; Saito, Shinya; Sakai, Kazuhiro; Sasaki, Toru; Sato, Goro; Sato, Kosuke; Sato, Rie; Sawada, Makoto; Schartel, Norbert; Serlemtsos, Peter J.; Seta, Hiromi; Shidatsu, Megumi; Simionescu, Aurora; Smith, Randall K.; Soong, Yang; Stawarz, Łukasz; Sugawara, Yasuharu; Sugita, Satoshi; Szymkowiak, Andrew; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shin'ichiro; Takei, Yoh; Tamagawa, Toru; Tamura, Takayuki; Tanaka, Takaaki; Tanaka, Yasuo; Tanaka, Yasuyuki T.; Tashiro, Makoto S.; Tawara, Yuzuru; Terada, Yukikatsu; Terashima, Yuichi; Tombesi, Francesco; Tomida, Hiroshi; Tsuboi, Yohko; Tsujimoto, Masahiro; Tsunemi, Hiroshi; Tsuru, Takeshi Go; Uchida, Hiroyuki; Uchiyama, Hideki; Uchiyama, Yasunobu; Ueda, Shutaro; Ueda, Yoshihiro; Uno, Shin'ichiro; Urry, C. Megan; Ursino, Eugenio; Watanabe, Shin; Werner, Norbert; Wilkins, Dan R.; Williams, Brian J.; Yamada, Shinya; Yamaguchi, Hiroya; Yamaoka, Kazutaka; Yamasaki, Noriko Y.; Yamauchi, Makoto; Yamauchi, Shigeo; Yaqoob, Tahir; Yatsu, Yoichi; Yonetoku, Daisuke; Zhuravleva, Irina; Zoghbi, Abderahmen; Sato, Toshiki; Nakaniwa, Nozomu; Murakami, Hiroaki; Guest, Benson

2018-06-01

We present results from the Hitomi X-ray observation of a young composite-type supernova remnant (SNR) G21.5-0.9, whose emission is dominated by the pulsar wind nebula (PWN) contribution. The X-ray spectra in the 0.8-80 keV range obtained with the Soft X-ray Spectrometer (SXS), Soft X-ray Imager, and Hard X-ray Imager (HXI) show a significant break in the continuum as previously found with the NuSTAR observation. After taking into account all known emissions from the SNR other than the PWN itself, we find that the Hitomi spectra can be fitted with a broken power law with photon indices of Γ1 = 1.74 ± 0.02 and Γ2 = 2.14 ± 0.01 below and above the break at 7.1 ± 0.3 keV, which is significantly lower than the NuSTAR result (˜9.0 keV). The spectral break cannot be reproduced by time-dependent particle injection one-zone spectral energy distribution models, which strongly indicates that a more complex emission model is needed, as suggested by recent theoretical models. We also search for narrow emission or absorption lines with the SXS, and perform a timing analysis of PSR J1833-1034 with the HXI and the Soft Gamma-ray Detector. No significant pulsation is found from the pulsar. However, unexpectedly, narrow absorption line features are detected in the SXS data at 4.2345 keV and 9.296 keV with a significance of 3.65 σ. While the origin of these features is not understood, their mere detection opens up a new field of research and was only possible with the high resolution, sensitivity, and ability to measure extended sources provided by an X-ray microcalorimeter.

NuSTAR Hard X-Ray Survey of the Galactic Center Region. II. X-Ray Point Sources

NASA Technical Reports Server (NTRS)

Hong, Jaesub; Mori, Kaya; Hailey, Charles J.; Nynka, Melania; Zhang, Shou; Gotthelf, Eric; Fornasini, Francesca M.; Krivonos, Roman; Bauer, Franz; Perez, Kerstin;

The X-ray absorption spectrum of 4U1700-37 and its implications for the stellar wind of the companion HD153919

NASA Technical Reports Server (NTRS)

White, N. E.; Kallman, T. R.; Swank, J. H.

1982-01-01

The first high resolution non-dispersive 2-60 KeV X-ray spectra of 4U1700-37 is presented. The continuum is typical of that found from X-ray pulsars; that is a flat power law between 2 and 10 keV and, beyond 10 keV, an exponential decay of characteristic energy varying between 10 and 20 keV. No X-ray pulsations were detected between 160 ms and 6 min with an amplitude greater than approximately 2%. The absorption measured at binary phases approximately 0.72 is comparable to that expected from the stellar wind of the primary. The gravitational capture of material in the wind is found to be more than enough to power the X-ray source. The increase in the average absorption after phi o approximately 0.5 is confirmed. The minimum level of adsorption is a factor of 2 or 3 lower than that reported by previous observers, which may be related to a factor of approximately 10 decline in the average X-ray luminosity over the same interval. Short term approximately 50% variations in adsorption are seen for the first time which appear to be loosely correlated with approximately 10 min flickering activity in the X-ray flux. These most likely originate from inhomogeneities in the stellar wind of the primary.

Design and construction of the Mini-Calorimeter of the AGILE satellite

NASA Astrophysics Data System (ADS)

Labanti, C.; Marisaldi, M.; Fuschino, F.; Galli, M.; Argan, A.; Bulgarelli, A.; Di Cocco, G.; Gianotti, F.; Tavani, M.; Trifoglio, M.

2009-01-01

AGILE is a small space mission of the Italian Space Agency (ASI) devoted to gamma-ray and hard-X astrophysics, successfully launched on April 23, 2007. The AGILE Payload is composed of three instruments: a gamma-ray imager based on a tungsten-silicon tracker (ST), for observations in the gamma ray energy range 30 MeV-50 GeV, a Silicon based X-ray detector, SuperAGILE (SA), for imaging in the range 18-60 keV and a CsI(Tl) Mini-Calorimeter (MCAL) that detects gamma rays or charged particles energy loss in the range 300 keV-100 MeV. MCAL is composed of 30 CsI(Tl) scintillator bars with photodiode readout at both ends, arranged in two orthogonal layers. MCAL can work both as a slave of the ST and as an independent gamma-ray detector for transients and gamma-ray bursts detection. In this paper a detailed description of MCAL is presented together with its performance.

NuSTAR Hard X-ray Observations of the Energetic Millisecond Pulsars PSR B1821-24, PSR B1937+21, and PSR J0218+4232

NASA Astrophysics Data System (ADS)

Gotthelf, Eric V.; Bogdanov, Slavko

2017-08-01

We present NuSTAR hard X-ray timing and spectroscopy of the three exceptionally energetic rotation-powered millisecond pulsars PSRs B1821-24, B1937+21, and J0218+4232. By correcting for frequency and phase drifts of the NuSTAR on-board clock we are able to recover the intrinsic hard X-ray pulse profiles of all three pulsars with a resolution down to <15 ms. The substantial reduction of background emission relative to previous broad-band X-ray observations allows us to detect for the first time pulsed emission up to ~50 keV, ~20 keV, and ~25 keV, for the three pulsars, respectively. We conduct phase-resolved spectroscopy in the 0.5 - 79 keV range for all three objects, obtaining the best yet measurements of the broad-band spectral shape and high-energy pulsed emission to date. We find extensions of the same power-law continua seen at lower energies, with no conclusive evidence for a spectral turnover or break. Extrapolation of the X-ray power-law spectrum to higher energies reveals that a turnover in the 100 keV to 100 MeV range is required to accommodate the high energy gamma-ray emission observed with Fermi LAT, similar to the broad-band spectral energy distribution observed for the Crab pulsar.

Room temperature X- and gamma-ray detectors using thallium bromide crystals

NASA Astrophysics Data System (ADS)

Hitomi, K.; Muroi, O.; Shoji, T.; Suehiro, T.; Hiratate, Y.

1999-10-01

Thallium bromide (TlBr) is a compound semiconductor with wide band gap (2.68eV) and high X- and γ-ray stopping power. The TlBr crystals were grown by the horizontal travelling molten zone (TMZ) method using purified material. Two types of room temperature X- and γ-ray detectors were fabricated from the TlBr crystals: TlBr detectors with high detection efficiency for positron annihilation γ-ray (511keV) detection and TlBr detectors with high-energy resolution for low-energy X-ray detection. The detector of the former type demonstrated energy resolution of 56keV FWHM (11%) for 511keV γ-rays. Energy resolution of 1.81keV FWHM for 5.9keV was obtained from the detector of the latter type. In order to analyze noise characteristics of the detector-preamplifier assembly, the equivalent noise charge (ENC) was measured as a function of the amplifier shaping time for the high-resolution detector. This analysis shows that parallel white noise and /1/f noise were dominant noise sources in the detector system. Current-voltage characteristics of the TlBr detector with a small Peltier cooler were also measured. Significant reduction of the detector leakage current was observed for the cooled detectors.

Measurement of the Energy and High-Pressure Dependence of X-ray-Induced Decomposition of Crystalline Strontium Oxalate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldberger, David; Evlyukhin, Egor; Cifligu, Petrika

We report measurements of the X-ray-induced decomposition of crystalline strontium oxalate (SrC2O4) as a function of energy and high pressure in two separate experiments. SrC2O4 at ambient conditions was irradiated with monochromatic synchrotron X-rays ranging in energy from 15 to 28 keV. A broad resonance of the decomposition yield was observed with a clear maximum when irradiating with ~20 keV X-rays and ambient pressure. Little or no decomposition was observed at 15 keV, which is below the Sr K-shell energy of 16.12 keV, suggesting that excitation of core electrons may play an important role in the destabilization of the C2O42–more » anion. A second experiment was performed to investigate the high-pressure dependence of the X-ray-induced decomposition of strontium oxalate at fixed energy. SrC2O4 was compressed in a diamond anvil cell (DAC) in the pressure range from 0 to 7.6 GPa with 1 GPa increments and irradiated in situ with 20 keV X-rays. A marked pressure dependence of the decomposition yield of SrC2O4 was observed with a decomposition yield maximum at around 1 GPa, suggesting that different crystal structures of the material play an important role in the decomposition process. This may be due in part to a phase transition observed near this pressure.« less

High efficiency microcolumnar Lu2O3:Eu scintillator thin film for hard X-ray microtomography

NASA Astrophysics Data System (ADS)

Marton, Z.; Bhandari, H. B.; Brecher, C.; Miller, S. R.; Singh, B.; Nagarkar, V. V.

2013-03-01

We have developed microstructured Lu2O3:Eu scintillator films capable of providing spatial resolution on the order of micrometers for hard X-ray imaging. In addition to their extraordinary resolution, Lu2O3:Eu films simultaneously provide high absorption efficiency for 20 to 100 keV X-rays, and bright 610 nm emission, with intensity rivalling 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, resulting in excessive measurement time and exposure to the specimen. Lu2O3:Eu would significantly improve that (99.9% @12 keV and 30% @ 70 keV). Important properties and features of our Lu2O3:Eu scintillator material, fabricated by our electron-beam physical vapour deposition (EB-PVD) process, combines superior density of 9.5 g/cm3, microcolumnar structure emitting 48000 photons/MeV whose wavelength is an ideal match for the underlying CCD detector array. We grew thin films measuring 5-50μm in thickness as well as covering areas up to 5 × 5 cm2 which can be a suitable basis for microtomography, digital radiography as well as CT and hard X-ray Micro-Tomography (XMT).

Measurement of the Energy and High-Pressure Dependence of X-ray-Induced Decomposition of Crystalline Strontium Oxalate.

PubMed

Goldberger, David; Evlyukhin, Egor; Cifligu, Petrika; Wang, Yonggang; Pravica, Michael

2017-09-28

We report measurements of the X-ray-induced decomposition of crystalline strontium oxalate (SrC 2 O 4 ) as a function of energy and high pressure in two separate experiments. SrC 2 O 4 at ambient conditions was irradiated with monochromatic synchrotron X-rays ranging in energy from 15 to 28 keV. A broad resonance of the decomposition yield was observed with a clear maximum when irradiating with ∼20 keV X-rays and ambient pressure. Little or no decomposition was observed at 15 keV, which is below the Sr K-shell energy of 16.12 keV, suggesting that excitation of core electrons may play an important role in the destabilization of the C 2 O 4 2- anion. A second experiment was performed to investigate the high-pressure dependence of the X-ray-induced decomposition of strontium oxalate at fixed energy. SrC 2 O 4 was compressed in a diamond anvil cell (DAC) in the pressure range from 0 to 7.6 GPa with 1 GPa increments and irradiated in situ with 20 keV X-rays. A marked pressure dependence of the decomposition yield of SrC 2 O 4 was observed with a decomposition yield maximum at around 1 GPa, suggesting that different crystal structures of the material play an important role in the decomposition process. This may be due in part to a phase transition observed near this pressure.

A New Observation of the Quiet Sun Soft X-ray (0.5-5 keV) Spectrum

NASA Astrophysics Data System (ADS)

Caspi, A.; Woods, T. N.; Stone, J.

2012-12-01

The solar corona is the brightest source of X-rays in the solar system, and the X-ray emission is highly variable with solar activity. While this is particularly true during solar flares, when emission can be enhanced by many orders of magnitude up to gamma-ray energies, even the so-called "quiet Sun" is bright in soft X-rays (SXRs), as the ~1-2 MK ambient plasma of the corona emits significant thermal bremsstrahlung up to ~5 keV. However, the actual solar SXR (0.5-5 keV) spectrum is not well known, particularly during quiet periods, as, with few exceptions, this energy range has not been systematically studied in many years. Previous observations include ultra-high-resolution but very narrow-band spectra from crystral spectrometers (e.g. Yohkoh/BCS), or integrated broadband irradiances from photometers (e.g. GOES/XRS, TIMED/XPS, etc.) that lack detailed spectral information. In recent years, broadband measurements with fair energy resolution (~0.5-0.7 keV FWHM) were made by SphinX on CORONAS-Photon and XRS on MESSENGER, although they did not extend below ~1 keV. We present observations of the quiet Sun SXR emission obtained using a new SXR spectrometer flown on the third SDO/EVE underflight calibration rocket (NASA 36.286). The commercial off-the-shelf Amptek X123 silicon drift detector, with an 8-micron Be window and custom aperture, measured the solar SXR emission from ~0.5 to >10 keV with ~0.15 keV FWHM resolution (though, due to hardware limitations, with only ~0.12 keV binning) and 2-sec cadence over ~5 minutes on 23 June 2012. Despite the rising solar cycle, activity on 23 June 2012 was abnormally low, with no visible active regions and GOES XRS emission near 2010 levels; we measured no solar counts above ~4 keV during the observation period. We compare our X123 measurements with spectra and broadband irradiances from other instruments, including the SphinX observations during the deep solar minimum of 2009, and with upper limits of >3 keV quiet Sun emission determined from RHESSI. We discuss the possible implications for X-ray-producing physical processes in the quiescent, active-region-free corona. The X123 spectrum could potentially serve as a reference for ~0.5-4 keV quiet Sun emission, to help improve solar spectral models such as CHIANTI and XPS Level 4. Our comparisons indicate that XPS Level 4 likely requires significant revisions in the SXR range, which may have downstream implications for the Earth ionosphere models that have used XPS Level 4 as their solar input.

A New Observation of the Quiet Sun Soft X-ray (0.5-5 keV) Spectrum

NASA Astrophysics Data System (ADS)

Caspi, Amir; Woods, Thomas N.; Stone, Jordan

2013-03-01

The solar corona is the brightest source of X-rays in the solar system, and the X-ray emission is highly variable with solar activity. While this is particularly true during solar flares, when emission can be enhanced by many orders of magnitude up to gamma-ray energies, even the so-called "quiet Sun" is bright in soft X-rays (SXRs), as the 1-2 MK ambient plasma of the corona emits significant thermal bremsstrahlung up to 5 keV. However, the actual solar SXR (0.5-5 keV) spectrum is not well known, particularly during quiet periods, as, with few exceptions, this energy range has not been systematically studied in many years. Previous observations include ultra-high-resolution but very narrow-band spectra from crystral spectrometers (e.g. Yohkoh/BCS), or integrated broadband irradiances from photometers (e.g. GOES/XRS, TIMED/XPS, etc.) that lack detailed spectral information. In recent years, broadband measurements with fair energy resolution ( 0.5-0.7 keV FWHM) were made by SphinX on CORONAS-Photon and XRS on MESSENGER, although they did not extend below 1 keV. We present observations of the quiet Sun SXR emission obtained using a new SXR spectrometer flown on the third SDO/EVE underflight calibration rocket (NASA 36.286). The commercial off-the-shelf Amptek X123 silicon drift detector, with an 8-micron Be window and custom aperture, measured the solar SXR emission from 0.5 to >10 keV with 0.15 keV FWHM resolution (though, due to hardware limitations, with only 0.12 keV binning) and 2-sec cadence over 5 minutes on 23 June 2012. Despite the rising solar cycle, activity on 23 June 2012 was abnormally low, with no visible active regions and GOES XRS emission near 2010 levels; we measured no solar counts above 4 keV during the observation period. We compare our X123 measurements with spectra and broadband irradiances from other instruments, including the SphinX observations during the deep solar minimum of 2009, and with upper limits of >3 keV quiet Sun emission determined from RHESSI. We discuss the possible implications for X-ray-producing physical processes in the quiescent, active-region-free corona. The X123 spectrum could potentially serve as a reference for 0.5-4 keV quiet Sun emission, to help improve solar spectral models such as CHIANTI and XPS Level 4. Our comparisons indicate that XPS Level 4 likely requires significant revisions in the SXR range, which may have downstream implications for the Earth ionosphere models that have used XPS Level 4 as their solar input.

Small-Size High-Current Generators for X-Ray Backlighting

NASA Astrophysics Data System (ADS)

Chaikovsky, S. A.; Artyomov, A. P.; Zharova, N. V.; Zhigalin, A. S.; Lavrinovich, I. V.; Oreshkin, V. I.; Ratakhin, N. A.; Rousskikh, A. G.; Fedunin, A. V.; Fedushchak, V. F.; Erfort, A. A.

2017-12-01

The paper deals with the soft X-ray backlighting based on the X-pinch as a powerful tool for physical studies of fast processes. Proposed are the unique small-size pulsed power generators operating as a low-inductance capacitor bank. These pulse generators provide the X-pinch-based soft X-ray source (hν = 1-10 keV) of micron size at 2-3 ns pulse duration. The small size and weight of pulse generators allow them to be transported to any laboratory for conducting X-ray backlighting of test objects with micron space resolution and nanosecond exposure time. These generators also allow creating synchronized multi-frame radiographic complexes with frame delay variation in a broad range.

Chandra X-Rays from the Redshift 7.54 Quasar ULAS J1342+0928

NASA Astrophysics Data System (ADS)

Bañados, Eduardo; Connor, Thomas; Stern, Daniel; Mulchaey, John; Fan, Xiaohui; Decarli, Roberto; Farina, Emanuele P.; Mazzucchelli, Chiara; Venemans, Bram P.; Walter, Fabian; Wang, Feige; Yang, Jinyi

2018-04-01

We present a 45 ks Chandra observation of the quasar ULAS J1342+0928 at z = 7.54. We detect {14.0}-3.7+4.8 counts from the quasar in the observed-frame energy range 0.5–7.0 keV (6σ detection), representing the most distant non-transient astronomical source identified in X-rays to date. The present data are sufficient only to infer rough constraints on the spectral parameters. We find an X-ray hardness ratio of { \\mathcal H }{ \\mathcal R }=-{0.51}-0.28+0.26 between the 0.5–2.0 keV and 2.0–7.0 keV ranges and derive a power-law photon index of {{Γ }}={1.95}-0.53+0.55. Assuming a typical value for high-redshift quasars of Γ = 1.9, ULAS J1342+0928 has a 2–10 keV rest-frame X-ray luminosity of {L}2-10={11.6}-3.5+4.3× {10}44 {erg} {{{s}}}-1. Its X-ray-to-optical power-law slope is {α }OX}=-{1.67}-0.10+0.16, consistent with the general trend indicating that the X-ray emission in the most bolometrically powerful quasars is weaker relative to their optical emission.

Enhancement of X-ray dose absorption for medical applications

NASA Astrophysics Data System (ADS)

Lim, Sara; Montenegro, Maximiliano; Nahar, Sultana; Pradhan, Anil; Barth, Rolf; Nakkula, Robin; Bell, Erica; Yu, Yan

2012-06-01

Interaction of high-Z (HZ) elements with X-rays occurs efficiently at specific resonant energies. Cross sections for photoionization rapidly decrease after the K-edge; higher energy X-rays are mostly Compton-scattered. These features restrict the energy range for the use of HZ moities for radiosensitization in cancer therapy. Conventional X-ray sources such as linear accelerators (LINAC) used in radiotherapy emit a broad spectrum up to MeV energies. We explore the dichotomy between X-ray radiotherapy in two ranges: (i) E < 100 keV including HZ sensitization, and (ii) E > 100 keV where sensitization is inefficient. We perform Monte Carlo numerical simulations of tumor tissue embedded with platinum compounds and gold nanoparticles and compute radiation dose enhancement factors (DEF) upon irradiation with 100 kV, 170 kV and 6 MV sources. Our results demonstrate that the DEF peak below 100 keV and fall sharply above 200 keV to very small values. Therefore most of the X-ray output from LINACs up to the MeV range is utilized very inefficiently. We also describe experimental studies for implementation of option (i) using Pt and Au reagents and selected cancer cell lines. Resultant radiation exposure to patients could be greatly reduced, yet still result in increased tumoricidal ability.

Measurement of the energy dependence of X-ray-induced decomposition of potassium chlorate.

PubMed

Pravica, Michael; Bai, Ligang; Sneed, Daniel; Park, Changyong

2013-03-21

We report the first measurements of the X-ray induced decomposition of KClO3 as a function of energy in two experiments. KClO3 was pressurized to 3.5 GPa and irradiated with monochromatic synchrotron X-rays ranging in energy from 15 to 35 keV in 5 keV increments. A systematic increase in the decomposition rate as the energy was decreased was observed, which agrees with the 1/E(3) trend for the photoelectric process, except at the lowest energy studied. A second experiment was performed to access lower energies (10 and 12 keV) using a beryllium gasket; suggesting an apparent resonance near 15 keV or 0.83 Ǻ maximizing the chemical decomposition rate. A third experiment was performed using KIO3 to ascertain the anionic dependence of the decomposition rate, which was observed to be far slower than in KClO3, suggesting that the O-O distance is the critical factor in chemical reactions. These results will be important for more efficiently initiating chemical decomposition in materials using selected X-ray wavelengths that maximize decomposition to aid useful hard X-ray-induced chemistry and contribute understanding of the mechanism of X-ray-induced decomposition of the chlorates.

L x-ray production cross sections in Th and U at 17.8, 25.8 and 46.9 keV photon energies

NASA Astrophysics Data System (ADS)

Kumar, Ajay; Puri, Sanjiv; Shahi, J. S.; Garg, M. L.; Mehta, D.; Singh, Nirmal

2001-02-01

The L x-ray production (XRP) differential cross sections in Th and U have been measured at the 17.8 keV incident photon energy (E_L3

The Weak Fe Fluorescence Line and Long-Term X-Ray Evolution of the Compton-Thick Active Galactic Nucleus in NGC7674

NASA Technical Reports Server (NTRS)

Ghandi, P.; Annuar, A.; Lansbury, G. B.; Stern, D.; Alexander, D. M.; Bauer, F. E.; Bianchi, S.; Boggs, S. E.; Boorman, P. G.; Brandt, W. N.;

X-ray Lobster Eye all-sky monitor for rocket experiment

NASA Astrophysics Data System (ADS)

Dániel, V.; Inneman, A.; Pína, L.; Zadražil, V.; Báča, T.; Stehlíková, V.; Nentvich, O.; Urban, M.; Maršíková, V.; McEntaffer, R.; Tutt, J.; Schulz, T.

2017-05-01

This paper presents a Lobster Eye (LE) X-ray telescope developed for the Water Recovery X-ray Rocket (WRX-R) experiment. The primary payload of the rocket experiment is a soft X-ray spectroscope developed by the Pennsylvania State University (PSU), USA. The Czech team participates by hard LE X-ray telescope as a secondary payload. The astrophysical objective of the rocket experiment is the Vela Supernova of size about 8deg x 8deg. In the center of the nebula is a neutron star with a strong magnetic field, roughly the mass of the Sun and a diameter of about 20 kilometers forming the Vela pulsar. The primary objective of WRX-R is the spectral measurement of the outer part of the nebula in soft X-ray and FOV of 3.25deg x 3.25deg. The secondary objective (hard LE X-ray telescope) is the Vela neutron star observation. The hard LE telescope consists of two X-ray telescopes with the Timepix detector. First telescope uses 2D LE Schmidt optics (2DLE- REX) with focal length over 1m and 4 Timepix detectors (2x2 matrix). The telescope FOV is 1.5deg x 1.5deg with spectral range from 3keV to 60keV. The second telescope uses 1D LE Schmidt optics (1D-LE-REX) with focal length of 25 cm and one Timepix detector. The telescope is made as a wide field with FOV 4.5deg x 3.5deg and spectral range from 3keV to 40keV. The rocket experiment serves as a technology demonstration mission for the payloads. The LE X-ray telescopes can be in the future used as all-sky monitor/surveyor. The astrophysical observation can cover the hard X-ray observation of astrophysical sources in time-domain, the GRBs surveying or the exploration of the gravitational wave sources.

Picosecond excimer laser-plasma x-ray source for microscopy, biochemistry, and lithography

NASA Astrophysics Data System (ADS)

Turcu, I. C. Edmond; Ross, Ian N.; Trenda, P.; Wharton, C. W.; Meldrum, R. A.; Daido, Hiroyuki; Schulz, M. S.; Fluck, P.; Michette, Alan G.; Juna, A. P.; Maldonado, Juan R.; Shields, Harry; Tallents, Gregory J.; Dwivedi, L.; Krishnan, J.; Stevens, D. L.; Jenner, T.; Batani, Dimitri; Goodson, H.

1994-02-01

At Rutherford Appleton Laboratory we developed a high repetition rate, picosecond, excimer laser system which generates a high temperature and density plasma source emitting approximately 200 mW (78 mW/sr) x ray average power at h(nu) approximately 1.2 KeV or 0.28 KeV < h(nu) < 0.53 KeV (the `water window'). At 3.37 nm wavelength the spectral brightness of the source is approximately 9 X 1011 photons/s/mm2/mrad2/0.1% bandwidth. The x-ray source serves a large user community for applications such as: scanning and holographic microscopy, the study of the biochemistry of DNA damage and repair, microlithography and spectroscopy.

Facilities and Techniques for X-Ray Diagnostic Calibration in the 100-eV to 100-keV Energy Range

NASA Astrophysics Data System (ADS)

Gaines, J. L.; Wittmayer, F. J.

1986-08-01

The Lawrence Livermore National Laboratory (LLNL) has been a pioneer in the field of x-ray diagnostic calibration for more than 20 years. We have built steady state x-ray sources capable of supplying fluorescent lines of high spectral purity in the 100-eV to 100-keV energy range, and these sources have been used in the calibration of x-ray detectors, mirrors, crystals, filters, and film. This paper discusses our calibration philosophy and techniques, and describes some of our x-ray sources. Examples of actual calibration data are presented as well.

Curved focusing crystals for hard X-ray astronomy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferrari, C., E-mail: ferrari@imem.cnr.it; Buffagni, E.; Bonnini, E.

A lens made by a properly arranged array of crystals can be used to focus x-rays of energy ranging from 30 to 500 keV for x-ray astronomy. Mosaic or curved crystals can be employed as x-ray optical elements. In this work self standing curved focusing Si and GaAs crystals in which the lattice bending is induced by a controlled damaging process on one side of planar crystals are characterized. Diffraction profiles in Laue geometry have been measured in crystals at x-ray energies E = 17, 59 and 120 keV. An enhancement of diffraction efficiency is found in asymmetric geometries.

Exposure Dose Reconstruction from EPR Spectra of Tooth Enamel Exposed to the Combined Effect of X-rays and Gamma Radiation

NASA Astrophysics Data System (ADS)

Kirillov, V. A.; Kuchuro, J. I.

2014-09-01

We have used EPR dosimetry on tooth enamel to show that the combined effect of x-rays with effective energy 34 keV and gamma radiation with average energy 1250 keV leads to a significant increase in the reconstructed absorbed dose compared with the applied dose from a gamma source or from an x-ray source or from both sources of electromagnetic radiation. In simulation experiments, we develop an approach to estimating the contribution of diagnostic x-rays to the exposure dose formed in the tooth enamel by the combined effect of x-rays and gamma radiation.

A Broad-band Spectral and Timing Study of the X-Ray Binary System Centaurus X-3

NASA Technical Reports Server (NTRS)

Audley, Michael Damian

1998-01-01

This dissertation describes a multi-mission investigation of the high mass X-ray binary pulsar Centaurus X-3. Cen X-3 was observed with the Broad Band X-Ray Telescope (BBXRT) in December 1990. This was the first high-resolution solid state X-ray spectrometer to cover the iron K fluorescence region. The Fe K emission feature was resolved into two components for the first time. A broad 6.7 keV feature was found to be a blend of lines from Fe XXI-Fe XXVI with energies ranging from 6.6 to 6.9 keV due to photoionization of the companion's stellar wind. A narrow line at 6.4 keV due to fluorescence of iron in relatively low ionization states was also found. The quasi-periodic oscillations (QPO) at about 40 mHz were used to estimate the surface magnetic field of Cen X-3 as approx. 2.6 x 10(exp 12) G and to predict that there should be a cyclotron scattering resonance absorption feature (CSRF) near 30 keV. In order to further resolve the iron line complex and to investigate the pulse-phase dependence of the iron line intensities, Cen X-3 was observed with the Advanced Satellite for Cosmology and Astrophysics (ASCA). Using ASCA's state-of-the-art non-dispersive X-ray spectrometers the 6.4 keV fluorescent iron line was found to be pulsing while the intensities of the 6.7 and 6.9 keV recombination lines do not vary with pulse phase. This confirms that the 6.4 keV line is due to reflection by relatively neutral matter close to the neutron star while the recombination lines originate in the extended stellar wind. The continuum spectrum was found to be modified by reflection from matter close to the neutron star. Observations with the EXOSAT GSPC were used to search for a CSRF. The EXOSAT spectra were consistent with the presence of a CSRF but an unambiguous detection was not possible because of a lack of sensitivity at energies higher than the cyclotron energy. Cen X-3 was then observed with the Rossi X-Ray Timing Explorer (RXTE) and evidence for a CSRF at 25.1 +/- 0.3 keV was found. This corresponds to a magnetic field of (2.16 +/- 0.03) X 10(exp 12) G and is consistent with the value obtained from the QPO analysis.

Suzaku Observation of Two Ultraluminous X-ray Sources in NGC 1313

NASA Technical Reports Server (NTRS)

Mizuno, T.; Miyawaki, R.; Ebisawa, K.; Kubota, A.; Miyamoto, M.; Winter, L.; Ueda, Y.; Isobe, N.; Dewangan, G.; Mushotzky, R.F.;

Coherence Length and Vibrations of the Coherence Beamline I13 at the Diamond Light Source

NASA Astrophysics Data System (ADS)

Wagner, U. H.; Parson, A.; Rau, C.

2017-06-01

I13 is a 250 m long hard x-ray beamline for imaging and coherent diffraction at the Diamond Light Source. The beamline (6 keV to 35 keV) comprises two independent experimental endstations: one for imaging in direct space using x-ray microscopy and one for imaging in reciprocal space using coherent diffraction based imaging techniques [1]. In particular the coherence experiments pose very high demands on the performance on the beamline instrumentation, requiring extensive testing and optimisation of each component, even during the assembly phase. Various aspects like the quality of optical components, the mechanical design concept, vibrations, drifts, thermal influences and the performance of motion systems are of particular importance. In this paper we study the impact of the front-end slit size (FE slit size), which determines the horizontal source size, onto the coherence length and the detrimental impact of monochromator vibrations using in-situ x-ray metrology in conjunction with fringe visibility measurements and vibration measurements, based on centroid tracking of an x-ray pencil beam with a photon-counting detector.

POET: a SMEX mission for gamma ray burst polarimetry

NASA Astrophysics Data System (ADS)

McConnell, Mark L.; Baring, Matthew; Bloser, Peter; Dwyer, Joseph F.; Emslie, A. Gordon; Ertley, Camden D.; Greiner, Jochen; Harding, Alice K.; Hartmann, Dieter H.; Hill, Joanne E.; Kaaret, Philip; Kippen, R. M.; Mattingly, David; McBreen, Sheila; Pearce, Mark; Produit, Nicolas; Ryan, James M.; Ryde, Felix; Sakamoto, Takanori; Toma, Kenji; Vestrand, W. Thomas; Zhang, Bing

2014-07-01

Polarimeters for Energetic Transients (POET) is a mission concept designed to t within the envelope of a NASA Small Explorer (SMEX) mission. POET will use X-ray and gamma-ray polarimetry to uncover the energy release mechanism associated with the formation of stellar-mass black holes and investigate the physics of extreme magnetic ields in the vicinity of compact objects. Two wide-FoV, non-imaging polarimeters will provide polarization measurements over the broad energy range from about 2 keV up to about 500 keV. A Compton scatter polarimeter, using an array of independent scintillation detector elements, will be used to collect data from 50 keV up to 500 keV. At low energies (2{15 keV), data will be provided by a photoelectric polarimeter based on the use of a Time Projection Chamber for photoelectron tracking. During a two-year baseline mission, POET will be able to collect data that will allow us to distinguish between three basic models for the inner jet of gamma-ray bursts.

NuSTARUnveils a Compton-Thick Type 2 Quasar in MrK 34

DOE PAGES

Gandhi, P.; Lansbury, G. B.; Alexander, D. M.; ...

2014-08-22

We present Nuclear Spectroscopic Telescope Array ( NuSTAR) 3-40 keV observations of the optically selected Type 2 quasar (QSO2) SDSS J1034+6001 or Mrk 34. The high-quality hard X-ray spectrum and archival XMM- Newton data can be fitted self-consistently with a reflection-dominated continuum and a strong Fe Kα fluorescence line with equivalent width >1 keV. Prior X-ray spectral fitting below 10 keV showed the source to be consistent with being obscured by Compton-thin column densities of gas along the line of sight, despite evidence for much higher columns from multiwavelength data. NuSTAR now enables a direct measurement of this column andmore » shows that N H lies in the Compton-thick (CT) regime. The new data also show a high intrinsic 2-10 keV luminosity of L 2-10 ~ 10 44 erg s –1, in contrast to previous low-energy X-ray measurements where L 2-10 ≲ 10 43 erg s –1 (i.e., X-ray selection below 10 keV does not pick up this source as an intrinsically luminous obscured quasar). Both the obscuring column and the intrinsic power are about an order of magnitude (or more) larger than inferred from pre- NuSTAR X-ray spectral fitting. Mrk 34 is thus a "gold standard" CT QSO2 and is the nearest non-merging system in this class, in contrast to the other local CT quasar NGC 6240, which is currently undergoing a major merger coupled with strong star formation. For typical X-ray bolometric correction factors, the accretion luminosity of Mrk 34 is high enough to potentially power the total infrared luminosity. In conclusion, X-ray spectral fitting also shows that thermal emission related to star formation is unlikely to drive the observed bright soft component below ~3 keV, favoring photoionization instead.« less

The MIT/OSO 7 catalog of X-ray sources - Intensities, spectra, and long-term variability

NASA Technical Reports Server (NTRS)

Markert, T. H.; Laird, F. N.; Clark, G. W.; Hearn, D. R.; Sprott, G. F.; Li, F. K.; Bradt, H. V.; Lewin, W. H. G.; Schnopper, H. W.; Winkler, P. F.

1979-01-01

This paper is a summary of the observations of the cosmic X-ray sky performed by the MIT 1-40-keV X-ray detectors on OSO 7 between October 1971 and May 1973. Specifically, mean intensities or upper limits of all third Uhuru or OSO 7 cataloged sources (185 sources) in the 3-10-keV range are computed. For those sources for which a statistically significant (greater than 20) intensity was found in the 3-10-keV band (138 sources), further intensity determinations were made in the 1-15-keV, 1-6-keV, and 15-40-keV energy bands. Graphs and other simple techniques are provided to aid the user in converting the observed counting rates to convenient units and in determining spectral parameters. Long-term light curves (counting rates in one or more energy bands as a function of time) are plotted for 86 of the brighter sources.

A Chandra-Swift View of Point Sources in Hickson Compact Groups: High AGN Fraction but a Dearth of Strong AGNs

NASA Technical Reports Server (NTRS)

Tzanavaris, P.; Gallagher, S. C.; Hornschemeier, A. E.; Fedotov, K.; Eracleous, M.; Brandt, W. N.; Desjardins, T. D.; Charlton, J. C.; Gronwall, C.

2014-01-01

We present Chandra X-ray point source catalogs for 9 Hickson Compact Groups (HCGs, 37 galaxies) at distances of 34-89 Mpc. We perform detailed X-ray point source detection and photometry and interpret the point source population by means of simulated hardness ratios. We thus estimate X-ray luminosities (L(sub x)) for all sources, most of which are too weak for reliable spectral fitting. For all sources, we provide catalogs with counts, count rates, power-law indices (gamma), hardness ratios, and L(sub X), in the full (0.5-8.0 keV), soft (0.5-2.0 keV), and hard (2.0-8.0 keV) bands. We use optical emission-line ratios from the literature to re-classify 24 galaxies as star-forming, accreting onto a supermassive black hole (AGNs), transition objects, or low-ionization nuclear emission regions. Two-thirds of our galaxies have nuclear X-ray sources with Swift/UVOT counterparts. Two nuclei have L(sub X),0.5-8.0 keV > 10(exp 42) erg s-1, are strong multi-wavelength active galactic nuclei (AGNs), and follow the known alpha OX-?L? (nearUV) correlation for strong AGNs. Otherwise, most nuclei are X-ray faint, consistent with either a low-luminosity AGN or a nuclear X-ray binary population, and fall in the 'non-AGN locus' in alpha OX-?L? (nearUV) space, which also hosts other normal galaxies. Our results suggest that HCG X-ray nuclei in high specific star formation rate spiral galaxies are likely dominated by star formation, while those with low specific star formation rates in earlier types likely harbor a weak AGN. The AGN fraction in HCG galaxies with MR (is) less than -20 and L(sub X),0.5-8.0 keV (is) greater than 10(exp 41) erg s-1 is 0.08+0.35 -0.01, somewhat higher than the 5% fraction in galaxy clusters.

Measurement of Lα and Lβ1,3,4 fluorescence cross sections of La, Ce, Pr and Nd induced by photons of energies between 7.01 keV and 8.75 keV

NASA Astrophysics Data System (ADS)

Reyes-Herrera, J.; Miranda, J.

2016-06-01

This study presents measurement results of x-ray production cross sections of Lα and Lβ1,3,4 emitted by four lanthanoid elements (La, Ce, Pr and Nd), after irradiation with Kα and Kβ X rays of the elements Co, Ni, Cu, and Zn (covering energies between 7.01 keV and 8.75 keV). Primary x-rays were induced in turn by the irradiation of thick targets of these elements with a beam of x-rays produced by a tube with an Rh anode, operating at 50 kV and 850 μA. The experimental results are compared with theoretical cross sections predicted using known tabulations of photoelectric cross sections. Dirac-Hartree-Slater (DHS) atomic parameters were used for these calculations. An acceptable match between experiment and both sets of tabulated data is found.

CORRELATION OF HARD X-RAY AND WHITE LIGHT EMISSION IN SOLAR FLARES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuhar, Matej; Krucker, Säm; Battaglia, Marina

A statistical study of the correlation between hard X-ray and white light emission in solar flares is performed in order to search for a link between flare-accelerated electrons and white light formation. We analyze 43 flares spanning GOES classes M and X using observations from the Reuven Ramaty High Energy Solar Spectroscopic Imager and Helioseismic and Magnetic Imager. We calculate X-ray fluxes at 30 keV and white light fluxes at 6173 Å summed over the hard X-ray flare ribbons with an integration time of 45 s around the peak hard-X ray time. We find a good correlation between hard X-raymore » fluxes and excess white light fluxes, with a highest correlation coefficient of 0.68 for photons with energy of 30 keV. Assuming the thick target model, a similar correlation is found between the deposited power by flare-accelerated electrons and the white light fluxes. The correlation coefficient is found to be largest for energy deposition by electrons above ∼50 keV. At higher electron energies the correlation decreases gradually while a rapid decrease is seen if the energy provided by low-energy electrons is added. This suggests that flare-accelerated electrons of energy ∼50 keV are the main source for white light production.« less

Soft X-Ray Emissions from Planets and Moons

NASA Technical Reports Server (NTRS)

Bhardwaj, A.; Gladstone, G. R.; Elsner, R. F.; Waite, J. H., Jr.; Grodent, D.; Cravens, T. E.; Howell, R. R.; Metzger, A. E.; Ostgaard, N.; Maurellis, A.;

Compound refractive lenses as prefocusing optics for X-ray FEL radiation

DOE PAGES

Heimann, Philip; MacDonald, Michael; Nagler, Bob; ...

2016-01-27

The performance of X-ray free-electron laser beamlines may be limited by the angular aperture. Compound refractive lenses (CRLs) can be employed to prefocus the X-ray beam, thereby increasing the beamline transmission. A prefocusing CRL was implemented in the X-ray transport of the Matter under Extreme Conditions Instrument at the Linac Coherent Light Source. A significant improvement in the beamline transmission was calculated over the 3–10 keV photon energy range. At 5 keV, the relative X-ray intensity was measured and a factor of four increase was seen in the beamline transmission. As a result, the X-ray focus was also determined bymore » the ablation imprint method.« less

Development of the hard x-ray monitor onboard WF-MAXI

NASA Astrophysics Data System (ADS)

Arimoto, Makoto; Yatsu, Yoichi; Kawai, Nobuyuki; Ikeda, Hirokazu; Harayama, Atsushi; Takeda, Shin'ichiro; Takahashi, Tadayuki; Tomida, Hiroshi; Ueno, Shiro; Kimura, Masashi; Mihara, Tatehiro; Serino, Motoko; Tsunemi, Hiroshi; Yoshida, Atsumasa; Sakamoto, Takanori; Kohmura, Tadayoshi; Negoro, Hitoshi; Ueda, Yoshihiro

2014-07-01

WF-MAXI is a mission to detect and localize X-ray transients with short-term variability as gravitational-wave (GW) candidates including gamma-ray bursts, supernovae etc. We are planning on starting observations by WF-MAXI to be ready for the initial operation of the next generation GW telescopes (e.g., KAGRA, Advanced LIGO etc.). WF-MAXI consists of two main instruments, Soft X-ray Large Solid Angle Camera (SLC) and Hard X-ray Monitor (HXM) which totally cover 0.7 keV to 1 MeV band. HXM is a multi-channel array of crystal scintillators coupled with APDs observing photons in the hard X-ray band with an effective area of above 100 cm2. We have developed an analog application specific integrated circuit (ASIC) dedicated for the readout of 32-channel APDs' signals using 0.35 μm CMOS technology based on Open IP project and an analog amplifier was designed to achieve a low-noise readout. The developed ASIC showed a low-noise performance of 2080 e- + 2.3 e-/pF at root mean square and with a reverse-type APD coupled to a Ce:GAGG crystal a good FWHM energy resolution of 6.9% for 662 keV -rays.

Quantitative Electron-Excited X-Ray Microanalysis of Borides, Carbides, Nitrides, Oxides, and Fluorides with Scanning Electron Microscopy/Silicon Drift Detector Energy-Dispersive Spectrometry (SEM/SDD-EDS) and NIST DTSA-II.

PubMed

Newbury, Dale E; Ritchie, Nicholas W M

2015-10-01

A scanning electron microscope with a silicon drift detector energy-dispersive X-ray spectrometer (SEM/SDD-EDS) was used to analyze materials containing the low atomic number elements B, C, N, O, and F achieving a high degree of accuracy. Nearly all results fell well within an uncertainty envelope of ±5% relative (where relative uncertainty (%)=[(measured-ideal)/ideal]×100%). Quantification was performed with the standards-based "k-ratio" method with matrix corrections calculated based on the Pouchou and Pichoir expression for the ionization depth distribution function, as implemented in the NIST DTSA-II EDS software platform. The analytical strategy that was followed involved collection of high count (>2.5 million counts from 100 eV to the incident beam energy) spectra measured with a conservative input count rate that restricted the deadtime to ~10% to minimize coincidence effects. Standards employed included pure elements and simple compounds. A 10 keV beam was employed to excite the K- and L-shell X-rays of intermediate and high atomic number elements with excitation energies above 3 keV, e.g., the Fe K-family, while a 5 keV beam was used for analyses of elements with excitation energies below 3 keV, e.g., the Mo L-family.

1RXS J173021.5-055933: a cataclysmic variable with a fast-spinning magnetic white dwarf

NASA Astrophysics Data System (ADS)

de Martino, D.; Matt, G.; Mukai, K.; Bonnet-Bidaud, J.-M.; Falanga, M.; Gänsicke, B. T.; Haberl, F.; Marsh, T. R.; Mouchet, M.; Littlefair, S. P.; Dhillon, V.

2008-04-01

Aims:We present the first X-ray observations with the XMM-Newton and INTEGRAL satellites of the recently discovered cataclysmic variable 1RXS J173021.5-055933, together with simultaneous UV and coordinated optical photometry aiming at characterising its broad-band temporal and spectral properties and classifying this system as a magnetic one. Methods: We performed a timing analysis of the X-ray, UV, and optical light curves to identify and to study the energy dependence of the fast 128 s pulsation over a wide energy range. X-ray spectral analysis in the broad 0.2-100 keV X-ray range was performed to characterise the peculiar emission properties of this source. Results: We find that the X-ray light curve is dominated by the spin period of the accreting white dwarf in contrast to the far-UV range, which turns out to be unmodulated at a 3σ level. Near-UV and optical pulses are instead detected at twice the spin frequency. We identify the contributions from two accreting poles that imply a moderately inclined dipole field allowing, one pole to dominate at energies at least up to 10 keV, and a secondary that instead is negligible above 5 keV. X-ray spectral analysis reveals the presence of multiple emission components consisting of optically thin plasma with temperatures ranging from 0.17 keV to 60 keV and a hot blackbody at ~90 eV. The spectrum is also strongly affected by peculiar absorption components consisting of two high-density (~3 × 1021~cm-2 and 2 × 1023~cm-2) intervening columns, plus a warm absorber. The last is detected from an OVII absorption edge at 0.74 keV, which suggests that photoionization of pre-shock material is also occurring in this system. Conclusions: The observed properties indicate that the accretor in 1RXS J173021.5-055933 is a white dwarf with a likely weak magnetic field, thus confirming this cataclysmic variable as an intermediate polar (IP) with one of the most extreme spin-to-orbit period ratios. This system also joins the small group of IPs showing a soft X-ray reprocessed component, suggesting that this characteristics is not uncommon in these systems. Based on observations obtained with XMM-Newton and INTEGRAL, ESA science missions with instruments and contributions directly funded by ESA Member States and NASA.

MULTI-KEV X-RAY YIELDS FROM HIGH-Z GAS TARGETS FIELDED AT OMEGA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kane, J O; Fournier, K B; May, M J

2010-11-04

The authors report on modeling of x-ray yield from gas-filled targets shot at the OMEGA laser facility. The OMEGA targets were 1.8 mm long, 1.95 mm in diameter Be cans filled with either a 50:50 Ar:Xe mixture, pure Ar, pure Kr or pure Xe at {approx} 1 atm. The OMEGA experiments heated the gas with 20 kJ of 3{omega} ({approx} 350 nm) laser energy delivered in a 1 ns square pulse. the emitted x-ray flux was monitored with the x-ray diode based DANTE instruments in the sub-keV range. Two-dimensional x-ray images (for energies 3-5 keV) of the targets were recordedmore » with gated x-ray detectors. The x-ray spectra were recorded with the HENWAY crystal spectrometer at OMEGA. Predictions are 2D r-z cylindrical with DCA NLTE atomic physics. Models generally: (1) underpredict the Xe L-shell yields; (2) overpredict the Ar K-shell yields; (3) correctly predict the Xe thermal yields; and (4) greatly underpredict the Ar thermal yields. However, there are spreads within the data, e.g. the DMX Ar K-shell yields are correctly predicted. The predicted thermal yields show strong angular dependence.« less

A catalogue of optical to X-ray spectral energy distributions of z ≈ 2 quasars observed with Swift - I. First results

NASA Astrophysics Data System (ADS)

Lawther, D.; Vestergaard, M.; Raimundo, S.; Grupe, D.

2017-06-01

We present the Swift optical to X-ray spectral energy distributions (SEDs) of 44 quasars at redshifts z ≈ 2 observed by Swift, part of a larger program to establish and characterize the optical through X-ray SEDs of moderate-redshift quasars. Here, we outline our analysis approach and present preliminary analysis and results for the first third of the full quasar sample. Not all quasars in the sample are detected in X-rays; all of the X-ray-detected objects so far are radio loud. As expected for radio-loud objects, they are X-ray bright relative to radio-quiet quasars of comparable optical luminosities, with an average αox =1.39 ± 0.03 (where αox is the power-law slope connecting the monochromatic flux at 2500 Å and at 2 keV), and display hard X-ray spectra. We find integrated 3000 Å-25 keV accretion luminosities of between 0.7 × 1046 erg s-1 and 5.2 × 1047 erg s-1. Based on single-epoch spectroscopic virial black hole mass estimates, we find that these quasars are accreting at substantial Eddington fractions, 0.1 ≲ L/LEdd ≲ 1.

Ground Calibration of the Astro-H (Hitomi) Soft X-Ray Spectrometer

NASA Technical Reports Server (NTRS)

Eckart, M. E.; Adams, J. S.; Boyce, K. R.; Brown, G. V.; Chiao, Meng P.; Fujimoto, R. J.; Haas, D.; Den Herder, J. W.; Ishisaki, Y.; Kelley, R. L.;

MOXE: An X-ray all-sky monitor for Soviet Spectrum-X-Gamma Mission

NASA Technical Reports Server (NTRS)

Priedhorsky, W.; Fenimore, E. E.; Moss, C. E.; Kelley, R. L.; Holt, S. S.

1989-01-01

A Monitoring Monitoring X-Ray Equipment (MOXE) is being developed for the Soviet Spectrum-X-Gamma Mission. MOXE is an X-ray all-sky monitor based on array of pinhole cameras, to be provided via a collaboration between Goddard Space Flight Center and Los Alamos National Laboratory. The objectives are to alert other observers on Spectrum-X-Gamma and other platforms of interesting transient activity, and to synoptically monitor the X-ray sky and study long-term changes in X-ray binaries. MOXE will be sensitive to sources as faint as 2 milliCrab (5 sigma) in 1 day, and cover the 2 to 20 KeV band.

SMM observations of gamma-ray transients. 2: A search for gamma-ray lines between 400 and 600 keV from the Crab Nebula

NASA Technical Reports Server (NTRS)

Harris, Michael J.; Share, Gerald H.; Leising, Mark D.

1994-01-01

We have search spectra obtained by the Solar Maximum Mission Gamma-Ray Spectrometer during 1981-1988 for evidence of transient gamma-ray lines from the Crab Nebula which have been reported by previous experiments at energies 400-460 keV and 539 keV. We find no evidence for significant emission in any of these lines on time scales between aproximately 1 day and approximately 1 yr. Our 3 sigma upper limits on the transient flux during 1 d intervals are approximately equal to 2.2 x 10(exp -3) photons/sq cm/s for narrow lines at any energy, and approximately equal to 2.9 x 10(exp -3) photons/sq cm/s for the 539 keV line if it is as broad as 42 keV Full Width at Half Maximum (FWHM). We also searched our data during the approximately 5 hr period on 1981 June 6 during which Owens, Myers, & Thompson (1985) reported a strong line at 405 keV. We detected no line down to a 3 upper sigma limit of 3.3 x 10(exp -3) photons/sq cm/s in disagreement with the flux 7.2 +/- 2.1 x 10(exp -3) photos/sq cm/s measured by Owens et al.

The cosmic X-ray experiment aboard HEAO-1

NASA Technical Reports Server (NTRS)

Rothschild, R. E.; Bolt, E.; Holt, S.; Serlemitsos, P. J.; Garmire, G.; Agrawal, P.; Reigler, G.; Bowyer, C. S.; Lampton, M.

1978-01-01

The HEAO-1 A-2 experiment, designed to study the large scale structure of the galaxy and the universe at X-ray energies is described. The instrument consists of six gas proportional counters of three types nominally covering the energy ranges of 0.15-3 keV, 1.2-20 keV, and 2.5-60 keV. The two low energy detectors have about 400 sq cm open area each while the four others have about 800 sq cm each. Dual field of view collimators allow the unambiguous determination of instrument internal background and diffuse X-ray brightness. Instrument characteristics and early performance are discussed.

Periodicity Analysis of X-ray Light Curves of SS 433

NASA Astrophysics Data System (ADS)

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

2016-03-01

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

Efficient Production of 4-KeV X Rays from Laser-Heated Xe Gas = Confined Within a Hohlraum

NASA Astrophysics Data System (ADS)

Grun, Jacob; Suter, Larry J.; Back, Christina A.; Decker, Chris; Kauffman, Robert L.; Davis, John F.

1996-11-01

Clean (debris-free) and efficient multi-kilovolt x-ray sources are needed for irradiating large military test objects and for use as backlighters in future Inertial Confinement Fusion experiments. Laser-plasma x-ray sources are particularly attractive for these uses since their spectrum can be controlled by proper choice of plasma material and laser intensity; and because many laser-plasma sources can be designed to produce little or no particulate debris. We report on an experiment in which we measured the production-efficiency, spectrum, and time history of 1-4 KeV x-rays from beryllium hohlraums which were filled with 1 and 2 atm of Xe gas and then irradiated by a 2-nsec pulse from the NOVA laser. It is predicted that 17be converted into > 4KeV x rays and 30history of >4KeV part of the spectrum is predicted to exhibit a dip in intensity whose depth and location vary with fill pressure and hohlraum size.. We also measured the debris produced by these sources. Work supported by the Defense Special Weapons Agency and the U.S. Department of Energy at LLNL under W-7405-ENG-48.

The Athena X-ray Integral Field Unit (X-IFU)

NASA Astrophysics Data System (ADS)

Pajot, F.; Barret, D.; Lam-Trong, T.; den Herder, J.-W.; Piro, L.; Cappi, M.; Huovelin, J.; Kelley, R.; Mas-Hesse, J. M.; Mitsuda, K.; Paltani, S.; Rauw, G.; Rozanska, A.; Wilms, J.; Barbera, M.; Douchin, F.; Geoffray, H.; den Hartog, R.; Kilbourne, C.; Le Du, M.; Macculi, C.; Mesnager, J.-M.; Peille, P.

2018-04-01

The X-ray Integral Field Unit (X-IFU) of the Advanced Telescope for High-ENergy Astrophysics (Athena) large-scale mission of ESA will provide spatially resolved high-resolution X-ray spectroscopy from 0.2 to 12 keV, with 5^' ' } pixels over a field of view of 5 arc minute equivalent diameter and a spectral resolution of 2.5 eV (FWHM) up to 7 keV. The core scientific objectives of Athena drive the main performance parameters of the X-IFU. We present the current reference configuration of the X-IFU, and the key issues driving the design of the instrument.

Performance of ASTRO-H Hard X-Ray Telescope (HXT)

NASA Technical Reports Server (NTRS)

Awaki, Hisamitsu; Kunieda, Hideyo; Ishida, Manabu; Matsumoto, Hironori; Furuzawa, Akihiro; Haba, Yohsito; Hayashi, Takayuki; Iizuka, Ryo; Ishibashi, Kazunori; Itoh, Masayuki;

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

NASA Technical Reports Server (NTRS)

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

2013-01-01

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

Design and development of the SIMBOL-X hard x-ray optics

NASA Astrophysics Data System (ADS)

Pareschi, G.; Attinà, P.; Basso, S.; Borghi, G.; Burkert, W.; Buzzi, R.; Citterio, O.; Civitani, M.; Conconi, P.; Cotroneo, V.; Cusumano, G.; Dell'Orto, E.; Freyberg, M.; Hartner, G. D.; Gorenstein, P.; Mattaini, E.; Mazzoleni, F.; Parodi, G.; Romaine, S.; Spiga, D.; Tagliaferri, G.; Valtolina, R.; Valsecchi, G.; Vernani, D.

2008-07-01

The SIMBOL-X formation-flight X-ray mission will be operated by ASI and CNES in 2014, with a large participation of the French and Italian high energy astrophysics scientific community. Also German and US Institutions are contributing in the implementation of the scientific payload. Thanks to the formation-flight architecture, it will be possible to operate a long (20 m) focal length grazing incidence mirror module, formed by 100 confocal multilayer-coated Wolter I shells. This system will allow us to focus X-rays over a very broad energy band, from 0.5 keV up to 80 keV and beyond, with more than two orders of magnitude improvement in angular resolution (20 arcsec HEW) and sensitivity (0.5 µCrab on axis @30 keV) compared to non focusing detectors used so far. The X-ray mirrors will be realized by Ni electroforming replication, already successfully used for BeppoSAX, XMM-Newton, and JET-X/SWIFT; the thickness trend will be about two times less than for XMM, in order to save mass. Multilayer reflecting coatings will be implemented, in order to improve the reflectivity beyond 10 keV and to increase the field of view 812 arcmin at 30 keV). In this paper, the SIMBOL-X optics design, technology and implementation challenges will be discussed; it will be also reported on recent results obtained in the context of the SIMBOL-X optics development activities.

Terrestrial gamma-ray flashes monitor demonstrator on CubeSat

NASA Astrophysics Data System (ADS)

Dániel, V.; Pína, L.; Inneman, A.; Zadražil, V.; Báča, T.; Platkevič, M.; Stehlíková, V.; Nentvich, O.; Urban, M.

2016-09-01

The CubeSat mission with the demonstrator of miniaturized X-ray telescope is presented. The paper presents one of the mission objectives of using the instrument for remote sensing of the Terrestrial Gamma-ray Flashes (TGFs). TGFs are intense sources of gamma-rays associated with lightning bolt activity and tropical thunderstorms. The measurement of TGFs exists and was measured by sounding rockets, high altitude balloons or several satellite missions. Past satellite missions were equipped with different detectors working from 10 keV up to 10 MeV. The RHESSI mission spectrum measurement of TGFs shows the maximum counts per second around 75 keV. The used detectors were in general big in volume and cannot be utilized by the CubeSat mission. The presented CubeSat is equipped with miniaturized X-ray telescope using the Timepix non-cooled pixel detector. The detector works between 3 and 60 keV in counting mode (dosimetry) or in spectrum mode with resolution 5 keV. The wide-field X-ray "Lobster-eye" optics/collimator (depending on energy) is used with a view angle of 3 degrees for the source location definition. The UV detectors with FOV 30 degrees and 1.5 degrees are added parallel with the optic as a part of the telescope. The telescope is equipped with software distinguishing between the photons and other particles. Using this software the TGF's detection is possible also in the field of South Atlantic anomaly. For the total ionization dose, the additional detector is used based on Silicone (12-60 keV) and CdTe (20 keV - 1 MeV). The presented instruments are the demonstrators suitable also for the astrophysical, sun and moon observation. The paper shows the details of TGF's observation modes, detectors details, data processing and handling system and mission. The CubeSat launch is planned to summer 2016.

Imaging Research With Non-Periodic Multilayers for Inertial Confinement Fusion Diagnostic Experiments

NASA Astrophysics Data System (ADS)

L. Wang, F.; Mu, B. Z.; Wang, Z. S.; Gu, C. S.; Zhang, Z.; Qin, S. J.; Chen, L. Y.

A grazing Kirkpatrick-Baez (K-B) microscope was designed for hard x-ray (8keV; Cu Ka radiation) imaging in Inertial Confinement Fusion (ICF) diagnostic experiments. Ray tracing software was used to simulate optical system performance. The optimized theoretical resolution of K-B microscope was about 2 micron and better than 10 micron in 200 micron field of view. Tungsten and boron carbide were chosen as multilayer materials and the multilayer was deposited onto the silicon wafer substrate and the reflectivity was measured by x-ray diffraction (XRD). The reflectivity of supermirror was about 20 % in 0.3 % of bandwidth. 8keV Cu target x-ray tube source was used in x-ray imaging experiments and the magnification of 1x and 2x x-ray images were obtained.

Soft X-ray observations of two BL Lacertae objects - Markarian 421 and 501

NASA Technical Reports Server (NTRS)

Singh, K. P.; Garmire, G. P.

1985-01-01

This paper reports on the soft X-ray (0.15-2.8 keV) observations of two BL Lacertae-type objects, viz., Mrk 421 and Mrk 501. The observations were made with the low-energy detectors on the HEAO 1 satellite during the period 1977 August-1978 December. Steep, soft X-ray power-law spectra with photon index Gamma = 3 are found for both Mrk 421 and Mrk 501. The power-law models are found to give a significantly better fit than the thermal models to the observed pulse-height spectra of Mrk 421 and Mrk 501. Day-to-day soft X-ray (0.25 keV band) intensity variations are observed only in Mrk 501. No significant change is found in Gamma from both the BL Lac objects during the period of observations. However, the sum of all the X-ray observations from 1976 until 1980 can be understood in terms of two spectral components of variable intensity to account for the X-ray emission observed between 0.15 and 20 keV from Mrk 421 and Mrk 501.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ceglio, N.M.; George, E.V.; Brooks, K.M.

The first successful demonstration of high resolution, tomographic imaging of a laboratory plasma using coded imaging techniques is reported. ZPCI has been used to image the x-ray emission from laser compressed DT filled microballoons. The zone plate camera viewed an x-ray spectral window extending from below 2 keV to above 6 keV. It exhibited a resolution approximately 8 ..mu..m, a magnification factor approximately 13, and subtended a radiation collection solid angle at the target approximately 10/sup -2/ sr. X-ray images using ZPCI were compared with those taken using a grazing incidence reflection x-ray microscope. The agreement was excellent. In addition,more » the zone plate camera produced tomographic images. The nominal tomographic resolution was approximately 75 ..mu..m. This allowed three dimensional viewing of target emission from a single shot in planar ''slices''. In addition to its tomographic capability, the great advantage of the coded imaging technique lies in its applicability to hard (greater than 10 keV) x-ray and charged particle imaging. Experiments involving coded imaging of the suprathermal x-ray and high energy alpha particle emission from laser compressed microballoon targets are discussed.« less

High temperature GaAs X-ray detectors

NASA Astrophysics Data System (ADS)

Lioliou, G.; Whitaker, M. D. C.; Barnett, A. M.

2017-12-01

Two GaAs p+-i-n+ mesa X-ray photodiodes were characterized for their electrical and photon counting X-ray spectroscopic performance over the temperature range of 100 °C to -20 °C. The devices had 10 μm thick i layers with different diameters: 200 μm (D1) and 400 μm (D2). The electrical characterization included dark current and capacitance measurements at internal electric field strengths of up to 50 kV/cm. The determined properties of the two devices were compared with previously reported results that were made with a view to informing the future development of photon counting X-ray spectrometers for harsh environments, e.g., X-ray fluorescence spectroscopy of planetary surfaces in high temperature environments. The best energy resolution obtained (Full Width at Half Maximum at 5.9 keV) decreased from 2.00 keV at 100 °C to 0.66 keV at -20 °C for the spectrometer with D1, and from 2.71 keV at 100 °C to 0.71 keV at -20 °C for the spectrometer with D2. Dielectric noise was found to be the dominant source of noise in the spectra, apart from at high temperatures and long shaping times, where the main source of photopeak broadening was found to be the white parallel noise.

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

PubMed

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

2006-06-01

A characteristic hot-filament type X-ray generator was constructed for irradiation of cultured cells. The source provides copper K, iron K, chromium K, molybdenum L, aluminium K and carbon K shell characteristic X-rays. When cultured mouse m5S cells were irradiated and frequencies of dicentrics were fitted to a linear-quadratic model, Y = alphaD + betaD2, the chromosomal effectiveness was not a simple function of photon energy. The alpha-terms increased with the decrease of the photon energy and then decreased with further decrease of the energy with an inflection point at around 10 keV. The beta-terms stayed constant for the photon energy down to 10 keV and then increased with further decrease of energy. Below 10 keV, the relative biological effectiveness (RBE) at low doses was proportional to the photon energy, which contrasted to that for high energy X- or gamma-rays where the RBE was inversely related with the photon energy. The reversion of the energy dependency occurred at around 1-2 Gy, where the RBE of soft X-rays was insensitive to X-ray energy. The reversion of energy-RBE relation at a moderate dose may shed light on the controversy on energy dependency of RBE of ultrasoft X-rays in cell survival experiments.

Indus-2 X-ray lithography beamline for X-ray optics and material science applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dhamgaye, V. P., E-mail: vishal@rrcat.gov.in; Lodha, G. S., E-mail: vishal@rrcat.gov.in

2014-04-24

X-ray lithography is an ideal technique by which high aspect ratio and high spatial resolution micro/nano structures are fabricated using X-rays from synchrotron radiation source. The technique has been used for fabricating optics (X-ray, visible and infrared), sensors and actuators, fluidics and photonics. A beamline for X-ray lithography is operational on Indus-2. The beamline offers wide lithographic window from 1-40keV photon energy and wide beam for producing microstructures in polymers upto size ∼100mm × 100mm. X-ray exposures are possible in air, vacuum and He gas environment. The air based exposures enables the X-ray irradiation of resist for lithography and alsomore » irradiation of biological and liquid samples.« less

Nanofiber-Based Bulk-Heterojunction Organic Solar Cells Using Coaxial Electrospinning

DTIC Science & Technology

2012-01-01

chains are likely oriented with the [010] direction, perpendicular to the substrate, in the fi lm device. Glancing incidence X - ray diffraction (GIXD...Electron and X - ray diffraction measurements were per- formed in order to study the structural order in annealed fi bers and devices. For reference... angle X - ray scattering (SAXS/WAXS) beamline 7.3.3 of the Advanced Light Source at Lawrence Berkeley National Laboratory at 10 keV (1.24 Å) from a bend

Development of grating-based x-ray Talbot interferometry at the advanced photon source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marathe, Shashidhara; Xiao Xianghui; Wojcik, Michael J.

2012-07-31

We report on the ongoing effort to develop hard x-ray Talbot interferometry at the Advanced Photon Source (APS), Argonne National Laboratory, USA. We describe the design of the interferometer and preliminary results obtained at 25 keV using a feather and a phantom sample lithographically fabricated of gold. We mention the future developmental goals and applications of this technique as a metrology tool for x-ray optics and beam wavefront characterization.

NuSTAR Hard X-Ray Observations of the Energetic Millisecond Pulsars PSR B1821-24, PSR B1937+21, and PSR J0218+4232

NASA Astrophysics Data System (ADS)

Gotthelf, E. V.; Bogdanov, S.

2017-08-01

We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray timing and spectroscopy of the three exceptionally energetic rotation-powered millisecond pulsars PSRs B1821-24, B1937+21, and J0218+4232. By correcting for the frequency and phase drifts of the NuSTAR onboard clock, we are able to recover the intrinsic hard X-ray pulse profiles of all three pulsars with a resolution down to ≤slant 15 μ {{s}}. The substantial reduction of background emission relative to previous broadband X-ray observations allows us to detect for the first time pulsed emission up to ˜50 keV, ˜20 keV, and ˜25 keV for the three pulsars, respectively. We conduct phase-resolved spectroscopy in the 0.5-79 keV range for all three objects, obtaining the best measurements yet of the broadband spectral shape and high-energy pulsed emission to date. We find extensions of the same power-law continua seen at lower energies, with no conclusive evidence for a spectral turnover or break. Extrapolation of the X-ray power-law spectrum to higher energies reveals that a turnover in the 100 keV to 100 MeV range is required to accommodate the high-energy γ-ray emission observed with Fermi-LAT, similar to the spectral energy distribution observed for the Crab pulsar.

Long term X-ray variability characteristics of the narrow-line Seyfert 1 galaxy RE J1034+396

NASA Astrophysics Data System (ADS)

Chaudhury, K.; Chitnis, V. R.; Rao, A. R.; Singh, K. P.; Bhattacharyya, Sudip; Dewangan, G. C.; Chakraborty, S.; Chandra, S.; Stewart, G. C.; Mukerjee, K.; Dey, R. K.

2018-05-01

We present the results of our study of the long term X-ray variability characteristics of the Narrow Line Seyfert 1 galaxy RE J1034+396. We use data obtained from the AstroSat satellite along with the light curves obtained from XMM-Newton and Swift-XRT. We use the 0.3 - 7.0 keV and 3 - 20 keV data, respectively, from the SXT and the LAXPC of AstroSat. The X-ray spectra in the 0.3 - 20 keV region are well fit with a model consisting of a power-law and a soft excess described by a thermal-Compton emission with a large optical depth, consistent with the earlier reported results. We have examined the X-ray light curves in the soft and hard X-ray bands of SXT and LAXPC, respectively, and find that the variability is slightly larger in the hard band. To investigate the variability characteristics of this source at different time scales, we have used X-ray light curves obtained from XMM-Newton data (200 s to 100 ks range) and Swift-XRT data (1 day to 100 day range) and find that there are evidences to suggest that the variability sharply increases at longer time scales. We argue that the mass of the black hole in RE J1034+396 is likely to be ˜3 × 106 M⊙, based on the similarity of the observed QPO to the high frequency QPO seen in the Galactic black hole binary, GRS 1915+105.

The NuSTAR Serendipitous Survey: The 40-month Catalog and the Properties of the Distant High-energy X-Ray Source Population

NASA Astrophysics Data System (ADS)

Lansbury, G. B.; Stern, D.; Aird, J.; Alexander, D. M.; Fuentes, C.; Harrison, F. A.; Treister, E.; Bauer, F. E.; Tomsick, J. A.; Baloković, M.; Del Moro, A.; Gandhi, P.; Ajello, M.; Annuar, A.; Ballantyne, D. R.; Boggs, S. E.; Brandt, W. N.; Brightman, M.; Chen, C.-T. J.; Christensen, F. E.; Civano, F.; Comastri, A.; Craig, W. W.; Forster, K.; Grefenstette, B. W.; Hailey, C. J.; Hickox, R. C.; Jiang, B.; Jun, H. D.; Koss, M.; Marchesi, S.; Melo, A. D.; Mullaney, J. R.; Noirot, G.; Schulze, S.; Walton, D. J.; Zappacosta, L.; Zhang, W. W.

2017-02-01

We present the first full catalog and science results for the Nuclear Spectroscopic Telescope Array (NuSTAR) serendipitous survey. The catalog incorporates data taken during the first 40 months of NuSTAR operation, which provide ≈20 Ms of effective exposure time over 331 fields, with an areal coverage of 13 deg2, and 497 sources detected in total over the 3-24 keV energy range. There are 276 sources with spectroscopic redshifts and classifications, largely resulting from our extensive campaign of ground-based spectroscopic follow-up. We characterize the overall sample in terms of the X-ray, optical, and infrared source properties. The sample is primarily composed of active galactic nuclei (AGNs), detected over a large range in redshift from z = 0.002 to 3.4 (median of < z> =0.56), but also includes 16 spectroscopically confirmed Galactic sources. There is a large range in X-ray flux, from {log}({f}3-24{keV}/{erg} {{{s}}}-1 {{cm}}-2)≈ -14 to -11, and in rest-frame 10-40 keV luminosity, from {log}({L}10-40{keV}/{erg} {{{s}}}-1)≈ 39 to 46, with a median of 44.1. Approximately 79% of the NuSTAR sources have lower-energy (<10 keV) X-ray counterparts from XMM-Newton, Chandra, and Swift XRT. The mid-infrared (MIR) analysis, using WISE all-sky survey data, shows that MIR AGN color selections miss a large fraction of the NuSTAR-selected AGN population, from ≈15% at the highest luminosities ({L}{{X}}> {10}44 erg s-1) to ≈80% at the lowest luminosities ({L}{{X}}< {10}43 erg s-1). Our optical spectroscopic analysis finds that the observed fraction of optically obscured AGNs (I.e., the type 2 fraction) is {F}{Type2}={53}-15+14 % , for a well-defined subset of the 8-24 keV selected sample. This is higher, albeit at a low significance level, than the type 2 fraction measured for redshift- and luminosity-matched AGNs selected by <10 keV X-ray missions.

The changing source of X-ray reflection in the radio-intermediate Seyfert 1 galaxy III Zw 2

NASA Astrophysics Data System (ADS)

Gonzalez, A. G.; Waddell, S. G. H.; Gallo, L. C.

2018-03-01

We report on X-ray observations of the radio-intermediate, X-ray bright Seyfert 1 galaxy, III Zw 2, obtained with XMM-Newton, Suzaku, and Swift over the past 17 yr. The source brightness varies significantly over yearly time-scales, but more modestly over periods of days. Pointed observations with XMM-Newton in 2000 and Suzaku in 2011 show spectral differences despite comparable X-ray fluxes. The Suzaku spectra are consistent with a power-law continuum and a narrow Gaussian emission feature at ˜6.4 keV, whereas the earlier XMM-Newton spectrum requires a broader Gaussian profile and soft-excess below ˜2 keV. A potential interpretation is that the primary power-law emission, perhaps from a jet base, preferentially illuminates the inner accretion disc in 2000, but the distant torus in 2011. The interpretation could be consistent with the hypothesized precessing radio jet in III Zw 2 that may have originated from disc instabilities due to an ongoing merging event.

Hard X-Ray Emission and the Ionizing Source in LINERs

NASA Technical Reports Server (NTRS)

Terashima, Yuichi; Ho, Luis C.; Ptak, Andrew F.

2000-01-01

We report X-ray fluxes in the 2-10 keV band from LINERs (low-ionization nuclear emission-line regions) and low-luminosity Seyfert galaxies obtained with the ASCA satellite. Observed X-ray luminosities are in the range between 4 x 10(exp 39) and 5 x 10(exp 41) ergs/s, which are significantly smaller than that of the "classical" low-luminosity Seyfert 1 galaxy NGC 4051. We found that X-ray luminosities in 2-10 keV of LINERs with broad H.alpha emission in their optical spectra (LINER 1s) are proportional to their Ha luminosities. This correlation strongly supports the hypothesis that the dominant ionizing source in LINER 1s is photoionization by hard photons from low-luminosity AGNs. On the other hand, the X-ray luminosities of most LINERs without broad H.alpha emission (LINER 2s) in our sample are lower than LINER 1s at a given H.alpha luminosity. The observed X-ray luminosities in these objects are insufficient to power their H.alpha luminosities, suggesting that their primary ionizing source is other than an AGN, or that an AGN, if present, is obscured even at energies above 2 keV.

An off-axis galaxy cluster merger: Abell 0141

NASA Astrophysics Data System (ADS)

Caglar, Turgay

2018-04-01

We present structural analysis results of Abell 0141 (z = 0.23) based on X-ray data. The X-ray luminosity map demonstrates that Abell 0141 (A0141) is a bimodal galaxy cluster, which is separated on the sky by ˜0.65 Mpc with an elongation along the north-south direction. The optical galaxy density map also demonstrates this bimodality. We estimate sub-cluster ICM temperatures of 5.17^{+0.20}_{-0.19} keV for A0141N and 5.23^{+0.24}_{-0.23} keV for A0141S. We obtain X-ray morphological parameters w = 0.034 ± 0.004, c = 0.113 ± 0.004, and w = 0.039 ± 0.004, c = 0.104 ± 0.005 for A0141N and A0141S, respectively. The resulting X-ray morphological parameters indicate that both sub-clusters are moderately disturbed non-cool core structures. We find a slight brightness jump in the bridge region, and yet, there is still an absence of strong X-ray emitting gas between sub-clusters. We discover a significantly hotspot (˜10 keV) between sub-clusters, and a Mach number M = 1.69^{+0.40}_{-0.37} is obtained by using the temperature jump condition. However, we did not find direct evidence for shock-heating between sub-clusters. We estimate the sub-clusters' central entropies as K0 > 100 keV cm2, which indicates that the sub-clusters are not cool cores. We find some evidence that the system undergoes an off-axis collision; however, the cores of each sub-clusters have not yet been destroyed. Due to the orientation of X-ray tails of sub-clusters, we suggest that the northern sub-cluster moves through the south-west direction, and the southern cluster moves through the north-east direction. In conclusion, we are witnessing an earlier phase of close core passage between sub-clusters.

Multi-Element X-Ray Shields for Spacecraft

DTIC Science & Technology

1983-12-30

34 Theoretical Photoionization Crcss Sections from I to 1500 keV", UCRL-51326 (1973). Values are given for shells and subshells as well as the atomic...effect data are from Hubbell, et al.1 The photoeffect data are from Scofield 2 at 1.0 keV and greater; values at 0.5 to 1.0 keV are from Veigele.3 An...example (not requiring interpolation) is given in Table I, the case of a 100 keV x-ray on lead. Each step in the process of filling the photoionization

In-flight performance of the soft x-ray spectrometer detector system on Astro-H

NASA Astrophysics Data System (ADS)

Porter, Frederick S.; Boyce, Kevin R.; Chiao, Meng P.; Eckart, Megan E.; Fujimoto, Ryuichi; Ishisaki, Yoshitaka; Kilbourne, Caroline Anne; Leutenegger, Maurice A.; McCammon, Daniel; Mitsuda, Kazuhisa; Sato, Kosuke; Seta, Hiromi; Sawada, Makoto; Sneiderman, Gary A.; Szymkowiak, Andrew E.; Takei, Yoh; Tashiro, Makoto S.; Tsujimoto, Masahiro; Watanabe, Tomomi; Yamada, Shinya

2018-01-01

The soft x-ray spectrometer (SXS) instrument was launched aboard the Astro-H (Hitomi) observatory on February 17, 2016. The SXS is based on a high-sensitivity x-ray calorimeter detector system that has been successfully deployed in many ground and suborbital spectrometers. The instrument was to provide essential diagnostics for nearly every class of x-ray emitting objects from the atmosphere of Jupiter to the outskirts of galaxy clusters, without degradation for spatially extended objects. The SXS detector system consisted of a 36-pixel cryogenic microcalorimeter array operated at a heat sink temperature of 50 mK. In preflight testing, the detector system demonstrated a resolving power of better than 1300 at 6 keV with a simultaneous bandpass from below 0.3 keV to above 12 keV with a timing precision better than 100 μs. In addition, a solid-state anticoincidence detector was placed directly behind the detector array for background suppression. The detector error budget included the measured interference from the SXS cooling system and the spacecraft. Additional margin for on-orbit gain stability and on-orbit spacecraft interference were also included predicting an on-orbit performance that meets or exceeds the 7-eV FWHM at 6-keV requirement. The actual on-orbit spectral resolution was better than 5 eV FWHM at 6 keV, easily satisfying the instrument requirement. Here, we discuss the actual on-orbit performance of the SXS detector system and compare this to performance in preflight testing and the on-orbit predictions. We will also discuss the on-orbit gain stability, additional on-orbit interference, and measurements of the on-orbit background.

MAXI/GSC detection of a rapid X-ray brightening from Mrk 421

NASA Astrophysics Data System (ADS)

Tachibana, Y.; Ueda, Y.; Negoro, H.; Ueno, S.; Tomida, H.; Ishikawa, M.; Sugawara, Y.; Isobe, N.; Shimomukai, R.; Mihara, T.; Sugizaki, M.; Nakahira, S.; Iwakiri, W.; Shidatsu, M.; Yatabe, F.; Takao, Y.; Matsuoka, M.; Kawai, N.; Sugita, S.; Yoshii, T.; Harita, S.; Muraki, Y.; Morita, K.; Yoshida, A.; Sakamoto, T.; Serino, M.; Kawakubo, Y.; Kitaoka, Y.; Hashimoto, T.; Tsunemi, H.; Yoneyama, T.; Nakajima, M.; Kawase, T.; Sakamaki, A.; Hori, T.; Tanimoto, A.; Oda, S.; Morita, T.; Yamada, S.; Tsuboi, Y.; Nakamura, Y.; Sasaki, R.; Kawai, H.; Sato, T.; Yamauchi, M.; Hanyu, C.; Hidaka, K.; Kawamuro, T.; Yamaoka, K.

2018-01-01

MAXI/GSC is detecting a bright X-ray flare from the BL Lac object Mrk 421. The MAXI daily fluxes for the last 5 days are following: MJD & emsp; 2-4 keV (mCrab) & emsp; 4-10 keV (mCrab) 58131 & emsp; 53 +- 5 & emsp; 52 +- 6 58132 & emsp; 34 +- 5 & emsp; 29 +- 5 58133 & emsp; 56 +- 5 & emsp; 53 +- 6 58134 & emsp; 91 +- 7 & emsp; 98 +- 7 58135 & emsp; 106 +- 8 & emsp; 124 +- 9 The current flux is comparable with the peak daily flux in the brightest X-ray flare from this object ever since the beginning of the MAXI observation (156 +- 11 mCrab in 1.5-10 keV on 2010 February 16, ATEL #2444; Isobe et al. 2010 PASJ 52, L55), and the X-ray brightening is still ongoing.

A laboratory 8 keV transmission full-field x-ray microscope with a polycapillary as condenser for bright and dark field imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baumbach, S., E-mail: baumbach@rheinahrcampus.de; Wilhein, T.; Kanngießer, B.

2015-08-15

This article introduces a laboratory setup of a transmission full-field x-ray microscope at 8 keV photon energy. The microscope operates in bright and dark field imaging mode with a maximum field of view of 50 μm. Since the illumination geometry determines whether the sample is illuminated homogeneously and moreover, if different imaging methods can be applied, the condenser optic is one of the most significant parts. With a new type of x-ray condenser, a polycapillary optic, we realized bright field imaging and for the first time dark field imaging at 8 keV photon energy in a laboratory setup. A detectormore » limited spatial resolution of 210 nm is measured on x-ray images of Siemens star test patterns.« less

A laboratory 8 keV transmission full-field x-ray microscope with a polycapillary as condenser for bright and dark field imaging.

PubMed

Baumbach, S; Kanngießer, B; Malzer, W; Stiel, H; Wilhein, T

2015-08-01

This article introduces a laboratory setup of a transmission full-field x-ray microscope at 8 keV photon energy. The microscope operates in bright and dark field imaging mode with a maximum field of view of 50 μm. Since the illumination geometry determines whether the sample is illuminated homogeneously and moreover, if different imaging methods can be applied, the condenser optic is one of the most significant parts. With a new type of x-ray condenser, a polycapillary optic, we realized bright field imaging and for the first time dark field imaging at 8 keV photon energy in a laboratory setup. A detector limited spatial resolution of 210 nm is measured on x-ray images of Siemens star test patterns.

X-ray source for mammography

DOEpatents

Logan, Clinton M.

1994-01-01

An x-ray source utilizing anode material which shifts the output spectrum to higher energy and thereby obtains higher penetrating ability for screening mammography application, than the currently utilized anode material. The currently used anode material (molybdenum) produces an energy x-ray spectrum of 17.5/19.6 keV, which using the anode material of this invention (e.g. silver, rhodium, and tungsten) the x-ray spectrum would be in the 20-35 keV region. Thus, the anode material of this invention provides for imaging of breasts with higher than average x-ray opacity without increase of the radiation dose, and thus reduces the risk of induced breast cancer due to the radiation dose administered for mammograms.

Soft X-ray Focusing Telescope Aboard AstroSat: Design, Characteristics and Performance

NASA Astrophysics Data System (ADS)

Singh, K. P.; Stewart, G. C.; Westergaard, N. J.; Bhattacharayya, S.; Chandra, S.; Chitnis, V. R.; Dewangan, G. C.; Kothare, A. T.; Mirza, I. M.; Mukerjee, K.; Navalkar, V.; Shah, H.; Abbey, A. F.; Beardmore, A. P.; Kotak, S.; Kamble, N.; Vishwakarama, S.; Pathare, D. P.; Risbud, V. M.; Koyande, J. P.; Stevenson, T.; Bicknell, C.; Crawford, T.; Hansford, G.; Peters, G.; Sykes, J.; Agarwal, P.; Sebastian, M.; Rajarajan, A.; Nagesh, G.; Narendra, S.; Ramesh, M.; Rai, R.; Navalgund, K. H.; Sarma, K. S.; Pandiyan, R.; Subbarao, K.; Gupta, T.; Thakkar, N.; Singh, A. K.; Bajpai, A.

2017-06-01

The Soft X-ray focusing Telescope (SXT), India's first X-ray telescope based on the principle of grazing incidence, was launched aboard the AstroSat and made operational on October 26, 2015. X-rays in the energy band of 0.3-8.0 keV are focussed on to a cooled charge coupled device thus providing medium resolution X-ray spectroscopy of cosmic X-ray sources of various types. It is the most sensitive X-ray instrument aboard the AstroSat. In its first year of operation, SXT has been used to observe objects ranging from active stars, compact binaries, supernova remnants, active galactic nuclei and clusters of galaxies in order to study its performance and quantify its characteriztics. Here, we present an overview of its design, mechanical hardware, electronics, data modes, observational constraints, pipeline processing and its in-orbit performance based on preliminary results from its characterization during the performance verification phase.

The cosmic X-ray background. [heao observations

NASA Technical Reports Server (NTRS)

Boldt, E. A.

1980-01-01

The cosmic X-ray experiment carried out with the A2 Instrument on HEAO-1 made systematics-free measurements of the extra-galactic X-ray sky and yielded the broadband spectral characteristics for two extreme aspects of this radiation. For the apparently isotropic radiation of cosmological origin that dominates the extragalactic X-ray flux ( 3 keV), the spectrum over the energy band of maximum intensity is remarkably well described by a thermal model with a temperature of a half-billion degrees. At the other extreme, broadband observations of individual extragalactic X-ray sources with HEAO-1 are restricted to objects within the present epoch. While the non-thermal hard spectral components associated with unevolved X-ray emitting active galaxies could account for most of the gamma-ray background, the contribution of such sources to the X-ray background must be relatively small. In contrast, the 'deep-space' sources detected in soft X-rays with the HEAO-2 telescope probably represent a major portion of the extragalactic soft X-ray ( 3 keV) background.

Time-dependent wave front propagation simulation of a hard x-ray split-and-delay unit: Towards a measurement of the temporal coherence properties of x-ray free electron lasers

DOE PAGES

Roling, S.; Zacharias, H.; Samoylova, L.; ...

2014-11-18

For the European x-ray free electron laser (XFEL) a split-and-delay unit based on geometrical wavefront beam splitting and multilayer mirrors is built which covers the range of photon energies from 5 keV up to 20 keV. Maximum delays between Δτ = ±2.5 ps at hν=20 keV and up to Δτ = ±23 ps at hν = 5 keV will be possible. Time-dependent wave-optics simulations have been performed by means of Synchrotron Radiation Workshop software for XFEL pulses at hν = 5 keV. The XFEL radiation was simulated using results of time-dependent simulations applying the self-amplified spontaneous emission code FAST. Mainmore » features of the optical layout, including diffraction on the beam splitter edge and optics imperfections measured with a nanometer optic component measuring machine slope measuring profiler, were taken into account. The impact of these effects on the characterization of the temporal properties of XFEL pulses is analyzed. An approach based on fast Fourier transformation allows for the evaluation of the temporal coherence despite large wavefront distortions caused by the optics imperfections. In this manner, the fringes resulting from time-dependent two-beam interference can be filtered and evaluated yielding a coherence time of τ c = 0.187 fs (HWHM) for real, nonperfect mirrors, while for ideal mirrors a coherence time of τ c = 0.191 fs (HWHM) is expected.« less

Titanium-Dioxide Nano-Fiber-Cotton Targets for Efficient Multi-keV X-Ray Generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanabe, M; Nishimura, H; Fujioka, S

Multi-keV x-ray generation from low-density (27 {+-} 7 mg/cc) nano-fiber-cotton targets composed of titanium-dioxide has been investigated. The cotton targets were heated volumetrically and supersonically to a peak electron temperature of 2.3 keV, which is optimal to yield Ti K-shell x rays. Considerable enhancement of conversion efficiency (3.7 {+-} 0.5%) from incident laser energy into Ti K-shell x rays (4-6 keV band) was attained in comparison with that (1.4 {+-} 0.9%) for a planar Ti-foil target.

Titanium dioxide nanofiber-cotton targets for efficient multi-keV x-ray generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanabe, Minoru; Nishimura, Hiroaki; Fujioka, Shinsuke

Multi-keV x-ray generation from low-density (27{+-}7 mg/cm{sup 3}) nanofiber-cotton targets composed of titanium dioxide has been investigated. The cotton targets were heated volumetrically and supersonically to a peak electron temperature of 2.3 keV, which is optimal to yield Ti K-shell x rays. Considerable enhancement of conversion efficiency [(3.7{+-}0.5)%] from incident laser energy into Ti K-shell x rays (4-6 keV band) was attained in comparison with that [(1.4{+-}0.9)%] for a planar Ti-foil target.

XTE J1550-564; GRB 990123

NASA Technical Reports Server (NTRS)

Harmon, B. A.; Finger, M. H.; McCollough, M. L.; Zhang, S. N.; Paciesas, W. S.; Wilson, C. A.

1999-01-01

The x-ray transient XTE Jl550-564 (IAUC 7008) was detected in Burst and Transient Source Experiment (BATSE) data beginning on Jan. 21. As of Jan. 23. the one-day averaged flux was 300 mCrab (+/- 20 percent, 20-100 keV), with a hard spectrum (power-law photon-number index -2.3 +/- 0.2). This is a reflare in hard x-rays, following the primary outburst in 1998 Sept.-Oct. (IAUC 7010). The source has been active in soft x-rays (2-12 keV) since about Dec. 18, according to observations by the Rossi X-ray Timing Explorer ASM.

Development and Calibration of the ART-XC Mirror Modules for the Spectrum Rontgen Gamma Mission

NASA Technical Reports Server (NTRS)

Ramsey, B.; Gubarev, M.; Elsner, R.; Kolodziejczak, J.; Odell, S.; Swartz, D.; Pavlinsky, M.; Tkachenko, A.; Lapshov, I.

2013-01-01

The Spectrum-Röntgen-Gamma (SRG) mission is a Russian-lead X-ray astrophysical observatory that carries two co-aligned X-ray telescope systems. The primary instrument is the German-led extended ROentgen Survey with an Imaging Telescope Array (eROSITA), a 7-module X-ray telescope system that covers the energy range from 0.2-12 keV. The complementary instrument is the Astronomical Roentgen Telescope -- X-ray Concentrator (ART-XC or ART), a 7-module Xray telescope system that provides higher energy coverage, up to 30 keV.

Development of Mirror Modules for the ART-XC Instrument aboard the Spectrum-Roentgen-Gamma Mission

NASA Technical Reports Server (NTRS)

Gubarev, Mikhail V.; Ramsey, Brian; O'Dell, Stephen L.; Elsner, Ronald F.; Kilaru, Kiranmayee; Atkins, Carolyn; Pavlinskiy, Mikhail N.; Tkachenko, Alexey V.; Lapshov, Igor Y.

2013-01-01

The Marshall Space Flight Center (MSFC) is developing x-ray mirror modules for the Astronomical Roengen Telescope- X-ray Concentrator (ART-XC) instrument on board the Spectrum-Roentgen-Gamma Mission. ART-XC will consist of seven co-aligned x-ray mirror modules with seven corresponding CdTe focal plane detectors. Each module provides an effective area of 65 sq cm at 8 keV, response out to 30 keV, and an angular resolution of 45 arcsec or better HPD. We will present a status of the ART x-ray module development at MSFC.

A Chandra-Swift View of Point Sources in Hickson Compact Groups: High AGN Fraction but a Dearth of Strong AGNs

NASA Astrophysics Data System (ADS)

Tzanavaris, P.; Gallagher, S. C.; Hornschemeier, A. E.; Fedotov, K.; Eracleous, M.; Brandt, W. N.; Desjardins, T. D.; Charlton, J. C.; Gronwall, C.

2014-05-01

We present Chandra X-ray point source catalogs for 9 Hickson Compact Groups (HCGs, 37 galaxies) at distances of 34-89 Mpc. We perform detailed X-ray point source detection and photometry and interpret the point source population by means of simulated hardness ratios. We thus estimate X-ray luminosities (LX ) for all sources, most of which are too weak for reliable spectral fitting. For all sources, we provide catalogs with counts, count rates, power-law indices (Γ), hardness ratios, and LX , in the full (0.5-8.0 keV), soft (0.5-2.0 keV), and hard (2.0-8.0 keV) bands. We use optical emission-line ratios from the literature to re-classify 24 galaxies as star-forming, accreting onto a supermassive black hole (AGNs), transition objects, or low-ionization nuclear emission regions. Two-thirds of our galaxies have nuclear X-ray sources with Swift/UVOT counterparts. Two nuclei have L X, 0.5-8.0 keV >1042 erg s-1, are strong multi-wavelength active galactic nuclei (AGNs), and follow the known αOX-νL ν (nearUV) correlation for strong AGNs. Otherwise, most nuclei are X-ray faint, consistent with either a low-luminosity AGN or a nuclear X-ray binary population, and fall in the "non-AGN locus" in αOX-νL ν (nearUV) space, which also hosts other normal galaxies. Our results suggest that HCG X-ray nuclei in high specific star formation rate spiral galaxies are likely dominated by star formation, while those with low specific star formation rates in earlier types likely harbor a weak AGN. The AGN fraction in HCG galaxies with MR <= -20 and L X, 0.5-8.0 keV >=1041 erg s-1 is 0.08^{+0.35}_{-0.01}, somewhat higher than the ~5% fraction in galaxy clusters.

Improving a high-efficiency, gated spectrometer for x-ray Thomson scattering experiments at the National Ignition Facility.

PubMed

Döppner, T; Kraus, D; Neumayer, P; Bachmann, B; Emig, J; Falcone, R W; Fletcher, L B; Hardy, M; Kalantar, D H; Kritcher, A L; Landen, O L; Ma, T; Saunders, A M; Wood, R D

2016-11-01

We are developing x-ray Thomson scattering for applications in implosion experiments at the National Ignition Facility. In particular we have designed and fielded MACS, a high-efficiency, gated x-ray spectrometer at 7.5-10 keV [T. Döppner et al., Rev. Sci. Instrum. 85, 11D617 (2014)]. Here we report on two new Bragg crystals based on Highly Oriented Pyrolytic Graphite (HOPG), a flat crystal and a dual-section cylindrically curved crystal. We have performed in situ calibration measurements using a brass foil target, and we used the flat HOPG crystal to measure Mo K-shell emission at 18 keV in 2nd order diffraction. Such high photon energy line emission will be required to penetrate and probe ultra-high-density plasmas or plasmas of mid-Z elements.

DTRA National Ignition Facility (NIF)

DTIC Science & Technology

2009-01-16

might provide a capability closer to that of UGT ‟s, particularly in the 15-100 keV X-ray band. We conclude that DRTA should monitor developments in...presently be tested. This is because, since the cessation of underground tests ( UGT ‟s), available facilities cannot produce X-ray environments of...provide a capability closer to that of UGT ‟s, particularly in the 15-100 keV X-ray band. However, source characteristics, including the level of

A high-density relativistic reflection origin for the soft and hard X-ray excess emission from Mrk 1044

NASA Astrophysics Data System (ADS)

Mallick, L.; Alston, W. N.; Parker, M. L.; Fabian, A. C.; Pinto, C.; Dewangan, G. C.; Markowitz, A.; Gandhi, P.; Kembhavi, A. K.; Misra, R.

2018-06-01

We present the first results from a detailed spectral-timing analysis of a long (˜130 ks) XMM-Newton observation and quasi-simultaneous NuSTAR and Swift observations of the highly-accreting narrow-line Seyfert 1 galaxy Mrk 1044. The broadband (0.3-50 keV) spectrum reveals the presence of a strong soft X-ray excess emission below ˜1.5 keV, iron Kα emission complex at ˜6 -7 keV and a `Compton hump' at ˜15 -30 keV. We find that the relativistic reflection from a high-density accretion disc with a broken power-law emissivity profile can simultaneously explain the soft X-ray excess, highly ionized broad iron line and the Compton hump. At low frequencies ([2 - 6] × 10-5 Hz), the power-law continuum dominated 1.5-5 keV band lags behind the reflection dominated 0.3-1 keV band, which is explained with a combination of propagation fluctuation and Comptonization processes, while at higher frequencies ([1 - 2] × 10-4 Hz), we detect a soft lag which is interpreted as a signature of X-ray reverberation from the accretion disc. The fractional root-mean-squared (rms) variability of the source decreases with energy and is well described by two variable components: a less variable relativistic disc reflection and a more variable direct coronal emission. Our combined spectral-timing analyses suggest that the observed broadband X-ray variability of Mrk 1044 is mainly driven by variations in the location or geometry of the optically thin, hot corona.

Efficient high-resolution hard x-ray imaging with transparent Lu2O3:Eu scintillator thin films

NASA Astrophysics Data System (ADS)

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.

Coherent x-ray diffraction imaging with nanofocused illumination.

PubMed

Schroer, C G; Boye, P; Feldkamp, J M; Patommel, J; Schropp, A; Schwab, A; Stephan, S; Burghammer, M; Schöder, S; Riekel, C

2008-08-29

Coherent x-ray diffraction imaging is an x-ray microscopy technique with the potential of reaching spatial resolutions well beyond the diffraction limits of x-ray microscopes based on optics. However, the available coherent dose at modern x-ray sources is limited, setting practical bounds on the spatial resolution of the technique. By focusing the available coherent flux onto the sample, the spatial resolution can be improved for radiation-hard specimens. A small gold particle (size <100 nm) was illuminated with a hard x-ray nanobeam (E=15.25 keV, beam dimensions approximately 100 x 100 nm2) and is reconstructed from its coherent diffraction pattern. A resolution of about 5 nm is achieved in 600 s exposure time.

NuSTAR Observations of the Compton-thick Active Galactic Nucleus and Ultraluminous X-Ray Source Candidate in NGC 5643

NASA Astrophysics Data System (ADS)

Annuar, A.; Gandhi, P.; Alexander, D. M.; Lansbury, G. B.; Arévalo, P.; Ballantyne, D. R.; Baloković, M.; Bauer, F. E.; Boggs, S. E.; Brandt, W. N.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Del Moro, A.; Hailey, C. J.; Harrison, F. A.; Hickox, R. C.; Matt, G.; Puccetti, S.; Ricci, C.; Rigby, J. R.; Stern, D.; Walton, D. J.; Zappacosta, L.; Zhang, W.

2015-12-01

We present two Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the local Seyfert 2 active galactic nucleus (AGN) and an ultraluminous X-ray source (ULX) candidate in NGC 5643. Together with archival data from Chandra, XMM-Newton, and Swift-BAT, we perform a high-quality broadband spectral analysis of the AGN over two decades in energy (˜0.5-100 keV). Previous X-ray observations suggested that the AGN is obscured by a Compton-thick (CT) column of obscuring gas along our line of sight. However, the lack of high-quality ≳10 keV observations, together with the presence of a nearby X-ray luminous source, NGC 5643 X-1, have left significant uncertainties in the characterization of the nuclear spectrum. NuSTAR now enables the AGN and NGC 5643 X-1 to be separately resolved above 10 keV for the first time and allows a direct measurement of the absorbing column density toward the nucleus. The new data show that the nucleus is indeed obscured by a CT column of NH ≳ 5 × 1024 cm-2. The range of 2-10 keV absorption-corrected luminosity inferred from the best-fitting models is L2-10,int = (0.8-1.7) × 1042 erg s-1, consistent with that predicted from multiwavelength intrinsic luminosity indicators. In addition, we also study the NuSTAR data for NGC 5643 X-1 and show that it exhibits evidence of a spectral cutoff at energy E ˜ 10 keV, similar to that seen in other ULXs observed by NuSTAR. Along with the evidence for significant X-ray luminosity variations in the 3-8 keV band from 2003 to 2014, our results further strengthen the ULX classification of NGC 5643 X-1.

Monte Carlo simulation of photon buildup factors for shielding materials in diagnostic x-ray facilities.

PubMed

Kharrati, Hedi; Agrebi, Amel; Karoui, Mohamed Karim

2012-10-01

A simulation of buildup factors for ordinary concrete, steel, lead, plate glass, lead glass, and gypsum wallboard in broad beam geometry for photons energies from 10 keV to 150 keV at 5 keV intervals is presented. Monte Carlo N-particle radiation transport computer code has been used to determine the buildup factors for the studied shielding materials. An example concretizing the use of the obtained buildup factors data in computing the broad beam transmission for tube potentials at 70, 100, 120, and 140 kVp is given. The half value layer, the tenth value layer, and the equilibrium tenth value layer are calculated from the broad beam transmission for these tube potentials. The obtained values compared with those calculated from the published data show the ability of these data to predict shielding transmission curves. Therefore, the buildup factors data can be combined with primary, scatter, and leakage x-ray spectra to provide a computationally based solution to broad beam transmission for barriers in shielding x-ray facilities.

Monte Carlo simulation of photon buildup factors for shielding materials in diagnostic x-ray facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kharrati, Hedi; Agrebi, Amel; Karoui, Mohamed Karim

2012-10-15

Purpose: A simulation of buildup factors for ordinary concrete, steel, lead, plate glass, lead glass, and gypsum wallboard in broad beam geometry for photons energies from 10 keV to 150 keV at 5 keV intervals is presented. Methods: Monte Carlo N-particle radiation transport computer code has been used to determine the buildup factors for the studied shielding materials. Results: An example concretizing the use of the obtained buildup factors data in computing the broad beam transmission for tube potentials at 70, 100, 120, and 140 kVp is given. The half value layer, the tenth value layer, and the equilibrium tenthmore » value layer are calculated from the broad beam transmission for these tube potentials. Conclusions: The obtained values compared with those calculated from the published data show the ability of these data to predict shielding transmission curves. Therefore, the buildup factors data can be combined with primary, scatter, and leakage x-ray spectra to provide a computationally based solution to broad beam transmission for barriers in shielding x-ray facilities.« less

Thermal characteristics of multi-wavelength emission during a B8.3 flare occurred on July 04, 2009

NASA Astrophysics Data System (ADS)

Awasthi, Arun Kumar; Sylwester, Barbara; Sylwester, Janusz; Jain, Rajmal

2015-08-01

We explore the temporal evolution of flare plasma parameters including temperature (T) - differential emission measure (DEM) relationship by analyzing high spectral and temporal cadence X-ray emission in 1.2-20 keV energy band, recorded by SphinX (Polish) and Solar X-ray Spectrometer (SOXS; Indian) instruments, during a B8.3 flare which occurred on July 04, 2009. SphinX records X-ray emission in 1.2-15 keV energy band with the temporal and spectral cadence as good as 6µs and 0.4 keV, respectively. On the other hand, SOXS provides X-ray observations in 4-25 keV energy band with the temporal and spectral resolution of 3s and 0.7 keV, respectively. In addition, we integrate co-temporal EUV line emission in 171, 194 and 284 angstrom obtained from STEREO mission in order to explore low-temperature response to the flare emission. In order to fit observed evolution of multi-wavelength emission during the flare, we incorporate multi-Gaussian and well-established Withbroe - Sylwester maximum likelihood DEM inversion algorithms. Thermal energetics are also estimated using geometrically corrected flaring loop structure obtained through EUV images of the active region from STEREO twin satellites. In addition, we also study the trigger and energy release scenario of this low-intensity class flare in terms of magnetic field as well as multi-wavelength emission.

Unique X-ray emission characteristics from volumetrically heated nanowire array plasmas

NASA Astrophysics Data System (ADS)

Rocca, J. J.; Bargsten, C.; Hollinger, R.; Shlyaptsev, V.; Pukhov, A.; Kaymak, V.; Capeluto, G.; Keiss, D.; Townsend, A.; Rockwood, A.; Wang, Y.; Wang, S.

2015-11-01

Highly anisotropic emission of hard X-ray radiation (h ν >10 keV) is observed when arrays of ordered nanowires (50 nm diameter wires of Au or Ni) are volumetrically heated by normal incidence irradiation with high contrast 50-60 fs laser pulses of relativistic intensity. The annular emission is in contrast with angular distribution of softer X-rays (h ν >1 KeV) from these targets and with the X-ray radiation emitted by polished flat targets, both of which are nearly isotropic. Model computations that make use the electron energy distribution computed by particle-in-cell simulations show that the unexpected annular distribution of the hard x-rays is the result of bremsstrahlung from fast electrons. Volumetric heating of Au nanowire arrays irradiated with an intensity of 2 x 10 19 W cm-2 is measured to convert laser energy into h ν>1KeV photons with a record efficiency of >8 percent into 2 π, creating a bright picosecond X-ray source for applications. Work supported by the Office of Fusion Energy Science of the U.S Department of Energy, and the Defense Threat Reduction Agency. A.P was supported by DFG project TR18.

ASCA Observations of W44

NASA Technical Reports Server (NTRS)

Hughes, John P.

1999-01-01

We report the detection, using data from the Advanced Satellite for Cosmology and Astrophysics (ASCA), of a hard X-ray source in the vicinity of the radio pulsar PSR B1853+01, which is located within the supernova remnant (SNR) W44. PSR B1853+01, a 267 ms pulsar, has to date been detected only in the radio band. Previous observations at soft X-ray energies (e.g., with ROSAT HRI) have failed to detect any significant X-ray emission (pulsed or unpulsed) from the pulsar. In addition, no high-energy emission (approx. > 4 keV) has been detected previously from W44. Over the 0.5-4.0 keV band, the ASCA data show soft thermal emission from W44, with a morphology very similar to that observed earlier by Einstein and ROSAT. In the high-energy band (4.0-9.5 keV), the SNR is, for the most part, invisible, although a source coincident with the position of PSR B1853+01 is evident. The observed ASCA spectra are consistent with a power-law origin (photon index approx. 2.3) for the X-ray emission from this source at a flux level (flux density approx. 0.5 micro Jy at I keV) consistent with previous upper limits. The maximum allowed size for the source is determined directiv from the ASCA data (<5 min.), while the minimum size is derived from the nondetection of a point source in the ROSAT HRI data (approx. > 30 sec.). Timing analysis of the hard X-ray source failed to detect pulsations at the pulsar's period. Based on these lines of evidence, we conclude that the new hard source in W44 represents an X-ray synchrotron nebula associated with PSR B1853+01, rather than the beamed output of the pulsar itself. This discoverv adds W44 to the small group of previously known plerionic SNRs This nebula lies at the low end of, but is consistent with, the correlation between X-ray luminosity and pulsar spin-down energy loss found for such objects, lending further support to our interpretation.

Sigma observations of the low mass X-ray binaries of the galactic bulge

NASA Technical Reports Server (NTRS)

Goldwurm, A.; Denis, M.; Paul, J.; Faisse, S.; Roques, J. P.; Bouchet, L.; Vedrenne, G.; Mandrou, P.; Sunyaev, R.; Churazov, E.

1995-01-01

The soft gamma-ray telescope (35-1300 keV) SIGMA aboard the high energy GRANAT space observatory has been monitoring the Galactic Bulge region for more than 2000 h of effective time since March 1990. In the resulting average 35-75 keV image we detected ten sources at a level of greater than 5 standard deviations, 6 of which can be identified with low mass X-ray binaries (LMXB). Among them, one is the 1993 X-ray nova in Ophiuchus (GRS 1726-249), one is an X-ray pulsar (GX 1+4), two are associated with X-ray bursters (GX 354-0 and A 1742-294) and two with bursting X-ray binaries in the globular clusters Terzan 2 and Terzan 1. Their spectral and long term variability behavior as measured by SIGMMA are presented and discussed.

High-Energy X-Ray Detection of G359.89-0.08 (SGR A-E): Magnetic Flux Tube Emission Powered by Cosmic Rays?

NASA Technical Reports Server (NTRS)

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

A practical superconducting-microcalorimeter X-ray spectrometer for beamline and laboratory science

DOE PAGES

Doriese, W. B.; Abbamonte, P.; Alpert, B. K.; ...

2017-05-01

We describe a series of microcalorimeter X-ray spectrometers designed for a broad suite of measurement applications. The chief advantage of this type of spectrometer is that it can be orders of magnitude more efficient at collecting X-rays than more traditional high-resolution spectrometers that rely on wavelength-dispersive techniques. This advantage is most useful in applications that are traditionally photon-starved and/or involve radiation-sensitive samples. Each energy-dispersive spectrometer is built around an array of several hundred transition-edge sensors (TESs). TESs are superconducting thin films that are biased into their superconducting-to-normal-metal transitions. The spectrometers share a common readout architecture and many design elements, suchmore » as a compact, 65 mK detector package, 8-column time-division-multiplexed superconducting quantum-interference device readout, and a liquid-cryogen-free cryogenic system that is a two-stage adiabatic-demagnetization refrigerator backed by a pulse-tube cryocooler. We have adapted this flexible architecture to mate to a variety of sample chambers and measurement systems that encompass a range of observing geometries. There are two different types of TES pixels employed. The first, designed for X-ray energies below 10 keV, has a best demonstrated energy resolution of 2.1 eV (full-width-at-half-maximum or FWHM) at 5.9 keV. The second, designed for X-ray energies below 2 keV, has a best demonstrated resolution of 1.0 eV (FWHM) at 500 eV. Our team has now deployed seven of these X-ray spectrometers to a variety of light sources, accelerator facilities, and laboratory-scale experiments; these seven spectrometers have already performed measurements related to their applications. Another five of these spectrometers will come online in the near future. We have applied our TES spectrometers to the following measurement applications: synchrotron-based absorption and emission spectroscopy and energy-resolved scattering; accelerator-based spectroscopy of hadronic atoms and particle-induced-emission spectroscopy; laboratory-based time-resolved absorption and emission spectroscopy with a tabletop, broadband source; and laboratory-based metrology of X-ray-emission lines. Here, we discuss the design, construction, and operation of our TES spectrometers and show first-light measurements from the various systems. Finally, because X-ray-TES technology continues to mature, we discuss improvements to array size, energy resolution, and counting speed that we anticipate in our next generation of TES-X-ray spectrometers and beyond.« less

A practical superconducting-microcalorimeter X-ray spectrometer for beamline and laboratory science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doriese, W. B.; Abbamonte, P.; Alpert, B. K.

We describe a series of microcalorimeter X-ray spectrometers designed for a broad suite of measurement applications. The chief advantage of this type of spectrometer is that it can be orders of magnitude more efficient at collecting X-rays than more traditional high-resolution spectrometers that rely on wavelength-dispersive techniques. This advantage is most useful in applications that are traditionally photon-starved and/or involve radiation-sensitive samples. Each energy-dispersive spectrometer is built around an array of several hundred transition-edge sensors (TESs). TESs are superconducting thin films that are biased into their superconducting-to-normal-metal transitions. The spectrometers share a common readout architecture and many design elements, suchmore » as a compact, 65 mK detector package, 8-column time-division-multiplexed superconducting quantum-interference device readout, and a liquid-cryogen-free cryogenic system that is a two-stage adiabatic-demagnetization refrigerator backed by a pulse-tube cryocooler. We have adapted this flexible architecture to mate to a variety of sample chambers and measurement systems that encompass a range of observing geometries. There are two different types of TES pixels employed. The first, designed for X-ray energies below 10 keV, has a best demonstrated energy resolution of 2.1 eV (full-width-at-half-maximum or FWHM) at 5.9 keV. The second, designed for X-ray energies below 2 keV, has a best demonstrated resolution of 1.0 eV (FWHM) at 500 eV. Our team has now deployed seven of these X-ray spectrometers to a variety of light sources, accelerator facilities, and laboratory-scale experiments; these seven spectrometers have already performed measurements related to their applications. Another five of these spectrometers will come online in the near future. We have applied our TES spectrometers to the following measurement applications: synchrotron-based absorption and emission spectroscopy and energy-resolved scattering; accelerator-based spectroscopy of hadronic atoms and particle-induced-emission spectroscopy; laboratory-based time-resolved absorption and emission spectroscopy with a tabletop, broadband source; and laboratory-based metrology of X-ray-emission lines. Here, we discuss the design, construction, and operation of our TES spectrometers and show first-light measurements from the various systems. Finally, because X-ray-TES technology continues to mature, we discuss improvements to array size, energy resolution, and counting speed that we anticipate in our next generation of TES-X-ray spectrometers and beyond.« less

A practical superconducting-microcalorimeter X-ray spectrometer for beamline and laboratory science

NASA Astrophysics Data System (ADS)

Doriese, W. B.; Abbamonte, P.; Alpert, B. K.; Bennett, D. A.; Denison, E. V.; Fang, Y.; Fischer, D. A.; Fitzgerald, C. P.; Fowler, J. W.; Gard, J. D.; Hays-Wehle, J. P.; Hilton, G. C.; Jaye, C.; McChesney, J. L.; Miaja-Avila, L.; Morgan, K. M.; Joe, Y. I.; O'Neil, G. C.; Reintsema, C. D.; Rodolakis, F.; Schmidt, D. R.; Tatsuno, H.; Uhlig, J.; Vale, L. R.; Ullom, J. N.; Swetz, D. S.

2017-05-01

We describe a series of microcalorimeter X-ray spectrometers designed for a broad suite of measurement applications. The chief advantage of this type of spectrometer is that it can be orders of magnitude more efficient at collecting X-rays than more traditional high-resolution spectrometers that rely on wavelength-dispersive techniques. This advantage is most useful in applications that are traditionally photon-starved and/or involve radiation-sensitive samples. Each energy-dispersive spectrometer is built around an array of several hundred transition-edge sensors (TESs). TESs are superconducting thin films that are biased into their superconducting-to-normal-metal transitions. The spectrometers share a common readout architecture and many design elements, such as a compact, 65 mK detector package, 8-column time-division-multiplexed superconducting quantum-interference device readout, and a liquid-cryogen-free cryogenic system that is a two-stage adiabatic-demagnetization refrigerator backed by a pulse-tube cryocooler. We have adapted this flexible architecture to mate to a variety of sample chambers and measurement systems that encompass a range of observing geometries. There are two different types of TES pixels employed. The first, designed for X-ray energies below 10 keV, has a best demonstrated energy resolution of 2.1 eV (full-width-at-half-maximum or FWHM) at 5.9 keV. The second, designed for X-ray energies below 2 keV, has a best demonstrated resolution of 1.0 eV (FWHM) at 500 eV. Our team has now deployed seven of these X-ray spectrometers to a variety of light sources, accelerator facilities, and laboratory-scale experiments; these seven spectrometers have already performed measurements related to their applications. Another five of these spectrometers will come online in the near future. We have applied our TES spectrometers to the following measurement applications: synchrotron-based absorption and emission spectroscopy and energy-resolved scattering; accelerator-based spectroscopy of hadronic atoms and particle-induced-emission spectroscopy; laboratory-based time-resolved absorption and emission spectroscopy with a tabletop, broadband source; and laboratory-based metrology of X-ray-emission lines. Here, we discuss the design, construction, and operation of our TES spectrometers and show first-light measurements from the various systems. Finally, because X-ray-TES technology continues to mature, we discuss improvements to array size, energy resolution, and counting speed that we anticipate in our next generation of TES-X-ray spectrometers and beyond.

A practical superconducting-microcalorimeter X-ray spectrometer for beamline and laboratory science.

PubMed

Doriese, W B; Abbamonte, P; Alpert, B K; Bennett, D A; Denison, E V; Fang, Y; Fischer, D A; Fitzgerald, C P; Fowler, J W; Gard, J D; Hays-Wehle, J P; Hilton, G C; Jaye, C; McChesney, J L; Miaja-Avila, L; Morgan, K M; Joe, Y I; O'Neil, G C; Reintsema, C D; Rodolakis, F; Schmidt, D R; Tatsuno, H; Uhlig, J; Vale, L R; Ullom, J N; Swetz, D S

2017-05-01

We describe a series of microcalorimeter X-ray spectrometers designed for a broad suite of measurement applications. The chief advantage of this type of spectrometer is that it can be orders of magnitude more efficient at collecting X-rays than more traditional high-resolution spectrometers that rely on wavelength-dispersive techniques. This advantage is most useful in applications that are traditionally photon-starved and/or involve radiation-sensitive samples. Each energy-dispersive spectrometer is built around an array of several hundred transition-edge sensors (TESs). TESs are superconducting thin films that are biased into their superconducting-to-normal-metal transitions. The spectrometers share a common readout architecture and many design elements, such as a compact, 65 mK detector package, 8-column time-division-multiplexed superconducting quantum-interference device readout, and a liquid-cryogen-free cryogenic system that is a two-stage adiabatic-demagnetization refrigerator backed by a pulse-tube cryocooler. We have adapted this flexible architecture to mate to a variety of sample chambers and measurement systems that encompass a range of observing geometries. There are two different types of TES pixels employed. The first, designed for X-ray energies below 10 keV, has a best demonstrated energy resolution of 2.1 eV (full-width-at-half-maximum or FWHM) at 5.9 keV. The second, designed for X-ray energies below 2 keV, has a best demonstrated resolution of 1.0 eV (FWHM) at 500 eV. Our team has now deployed seven of these X-ray spectrometers to a variety of light sources, accelerator facilities, and laboratory-scale experiments; these seven spectrometers have already performed measurements related to their applications. Another five of these spectrometers will come online in the near future. We have applied our TES spectrometers to the following measurement applications: synchrotron-based absorption and emission spectroscopy and energy-resolved scattering; accelerator-based spectroscopy of hadronic atoms and particle-induced-emission spectroscopy; laboratory-based time-resolved absorption and emission spectroscopy with a tabletop, broadband source; and laboratory-based metrology of X-ray-emission lines. Here, we discuss the design, construction, and operation of our TES spectrometers and show first-light measurements from the various systems. Finally, because X-ray-TES technology continues to mature, we discuss improvements to array size, energy resolution, and counting speed that we anticipate in our next generation of TES-X-ray spectrometers and beyond.

Importance of Doppler broadening in Compton scatter imaging techniques

NASA Astrophysics Data System (ADS)

Rao, Donepudi V.; Takeda, Tohoru; Itai, Yuji; Seltzer, S. M.; Hubbell, John H.; Zeniya, Tsutomu; Akatsuka, Takao; Cesareo, Roberto; Brunetti, Antonio; Gigante, Giovanni E.

2001-12-01

Compton scattering is a potential tool for the determination of bone mineral content or tissue density for dose planning purposes, and requires knowledge of the energy distribution of the X-rays through biological materials of medical interest in the X-ray and (gamma) -ray region. The energy distribution is utilized in a number of ways in diagnostic radiology, for example, in determining primary photon spectra, electron densities in separate volumes, and in tomography and imaging. The choice of the X-ray energy is more related to X-ray absorption, where as that of the scattering angle is more related to geometry. The evaluation of all the contributions are mandatory in Compton profile measurements and is important in X-ray imaging systems in order to achieve good results. In view of this, Compton profile cross-sections for few biological materials are estimated at nineteen K(alpha) X-ray energies and 60 keV (Am-241) photons. Energy broadening, geometrical broadening from 1 to 180 degree(s), FWHM of J(Pz) and FWHM of Compton energy broadening has been evaluated at various incident photon energies. These values are estimated around the centroid of the Compton profile with an energy interval of 0.1 keV and 1.0 keV for 60 keV photons. The interaction cross sections for the above materials are estimated using fractions-by-weight of the constituent elements. Input data for these tables are purely theoretical.

The broad-band X-ray spectral variability of Mrk 841

NASA Technical Reports Server (NTRS)

George, I. M.; Nandra, K.; Fabian, A. C.; Turner, T. J.; Done, C.; Day, C. S. R.

1993-01-01

A detailed spectral analysis of five X-ray observations of Mrk 841 with the EXOSAT, Ginga, and ROSAT satellites is reported. Variability is apparent in both the soft (0.1-1.0 keV) and medium (1-20 keV) energy bands. Above, 1 keV, the spectra are adequately modeled by a power law with a strong emission line of equivalent width 450 eV. The large equivalent width of the emission line indicates a strongly enhanced reflection component of the source compared with other Seyferts observed with Ginga. The implications of the results of the analysis for physical models of the emission regions in this and other X-ray bright Seyferts are briefly examined.

Soft X-ray production by photon scattering in pulsating binary neutron star sources

NASA Technical Reports Server (NTRS)

Bussard, R. W.; Meszaros, P.; Alexander, S.

1985-01-01

A new mechanism is proposed as a source of soft (less than 1 keV) radiation in binary pulsating X-ray sources, in the form of photon scattering which leaves the electron in an excited Landau level. In a plasma with parameters typical of such sources, the low-energy X-ray emissivity of this mechanism far exceeds that of bremsstrahlung. This copious source of soft photons is quite adequate to provide the seed photons needed to explain the power-law hard X-ray spectrum by inverse Comptonization on the hot electrons at the base of the accretion column.

High spectral resolution studies of gamma ray bursts on new missions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Desai, U. D.; Acuna, M. H.; Cline, T. L.

1996-08-01

Two new missions will be launched in 1996 and 1997, each carrying X-ray and gamma ray detectors capable of high spectral resolution at room temperature. The Argentine Satelite de Aplicaciones Cientificas (SAC-B) and the Small Spacecraft Technology Initiative (SSTI) Clark missions will each carry several arrays of X-ray detectors primarily intended for the study of solar flares and gamma-ray bursts. Arrays of small (1 cm{sup 2}) cadmium zinc telluride (CZT) units will provide x-ray measurements in the 10 to 80 keV range with an energy resolution of {approx_equal}6 keV. Arrays of both silicon avalanche photodiodes (APD) and P-intrinsic-N (PIN) photodiodesmore » (for the SAC-B mission only) will provide energy coverage from 2-25 keV with {approx_equal}1 keV resolution. For SAC-B, higher energy spectral data covering the 30-300 keV energy range will be provided by CsI(Tl) scintillators coupled to silicon APDs, resulting in similar resolution but greater simplicity relative to conventional CsI/PMT systems. Because of problems with the Pegasus launch vehicle, the launch of SAC-B has been delayed until 1997. The launch of the SSTI Clark mission is scheduled for June 1996.« less

EUV Spectroscopy of High-redshift X-ray Objects

NASA Astrophysics Data System (ADS)

Kowalski, Michael Paul; Wolff, M. T.; Wood, K. S.; Barbee, T. W., Jr.

2010-03-01

As astronomical observations are pushed to cosmological distances (z>3) the spectral energy distributions of X-ray objects, AGNs for example, will have their maxima redshifted into the EUV waveband ( 90-912 Å/0.1-0.01 keV). Consequently, a wealth of spectral diagnostics, provided by, for example, the Fe L-shell complex ( 60-6 Å/0.2-2.0 keV) and the O VII/VIII lines ( 20 Å/0.5 keV), will be lost to X-ray instruments operating at traditional ( 0.5-10 keV) and higher X-ray energies. There are precedents in other wavebands. For example, HST evolutionary studies will become largely the province of JWST. Despite the successes of EUVE, the ROSAT WFC, and the Chandra LETG, the EUV continues to be unappreciated and under-utilized, partly because of a preconception that absorption by neutral galactic Hydrogen in the ISM prevents any useful extragalactic measurements at all EUV wavelengths and, until recently, by a lack of a suitable enabling technology. Thus, if future planned X-ray missions (e.g., IXO, Gen-X) are optimized again for traditional X-ray energies, their performance (effective area, resolving power) will be cut off at ultrasoft X-ray energies or at best be radically reduced in the EUV. This opens up a critical gap in performance located right at short EUV wavelengths, where the critical X-ray spectral transitions occur in high-z objects. However, normal-incidence multilayer-grating technology, which performs best precisely at such wavelengths, together with advanced nano-laminate fabrication techniques have been developed and are now mature to the point where advanced EUV instrument designs with performance complementary to IXO and Gen-X are practical. Such EUV instruments could be flown either independently or as secondary instruments on these X-ray missions. We present here a critical examination of the limits placed on extragalactic EUV measurements by ISM absorption, the range where high-z measurements are practical, and the requirements this imposes on next-generation instrument designs.

An accurate method for computer-generating tungsten anode x-ray spectra from 30 to 140 kV.

PubMed

Boone, J M; Seibert, J A

1997-11-01

A tungsten anode spectral model using interpolating polynomials (TASMIP) was used to compute x-ray spectra at 1 keV intervals over the range from 30 kV to 140 kV. The TASMIP is not semi-empirical and uses no physical assumptions regarding x-ray production, but rather interpolates measured constant potential x-ray spectra published by Fewell et al. [Handbook of Computed Tomography X-ray Spectra (U.S. Government Printing Office, Washington, D.C., 1981)]. X-ray output measurements (mR/mAs measured at 1 m) were made on a calibrated constant potential generator in our laboratory from 50 kV to 124 kV, and with 0-5 mm added aluminum filtration. The Fewell spectra were slightly modified (numerically hardened) and normalized based on the attenuation and output characteristics of a constant potential generator and metal-insert x-ray tube in our laboratory. Then, using the modified Fewell spectra of different kVs, the photon fluence phi at each 1 keV energy bin (E) over energies from 10 keV to 140 keV was characterized using polynomial functions of the form phi (E) = a0[E] + a1[E] kV + a2[E] kV2 + ... + a(n)[E] kVn. A total of 131 polynomial functions were used to calculate accurate x-ray spectra, each function requiring between two and four terms. The resulting TASMIP algorithm produced x-ray spectra that match both the quality and quantity characteristics of the x-ray system in our laboratory. For photon fluences above 10% of the peak fluence in the spectrum, the average percent difference (and standard deviation) between the modified Fewell spectra and the TASMIP photon fluence was -1.43% (3.8%) for the 50 kV spectrum, -0.89% (1.37%) for the 70 kV spectrum, and for the 80, 90, 100, 110, 120, 130 and 140 kV spectra, the mean differences between spectra were all less than 0.20% and the standard deviations were less than approximately 1.1%. The model was also extended to include the effects of generator-induced kV ripple. Finally, the x-ray photon fluence in the units of photons/mm2 per mR was calculated as a function of HVL, kV, and ripple factor, for various (water-equivalent) patient thicknesses (0, 10, 20, and 30 cm). These values may be useful for computing the detective quantum efficiency, DQE(f), of x-ray detector systems. The TASMIP algorithm and ancillary data are made available on line at http:/(/)www.aip.org/epaps/epaps.html.

The Physics of AGN, a Deep Understanding of the Quasar 3C 273

NASA Technical Reports Server (NTRS)

Courvoisier, T.; Bottcher, Markus

2004-01-01

Upon our successful AO-1 proposal no. 120023, the quasar 3C 273 has been observed with INTEGRAL in 3 epochs in January 2003. The first observation, on January 5, 2003, with a total INTEGRAL exposure of 1.2 x 10(exp 5) s, was simultaneous with RXTE and XMM- Newton observations. Two more INTEGRAL observations were carried out on January 11, 2003 (exposure: lo4 s) and January 17, 2003 (exposure: 1.1 x 10(exp 5) s). The source was detected with high significance by all INTEGRAL instruments, the OMC, JEM-X, SPI, and IBIS/ISGRI. Being one of the first INTEGRAL observations simultaneous with XMM and RXTE, our observations were also used to fix the cross calibration with those instruments. The combined spectrum resulting from the XMM-Newton, JEM-X, RXTE, SPI and ISGRI X-ray / soft gamma-ray observations is consistent with a straight power-law of photon index Gamma = (1.73 +/- 0.015) between 3 keV and at least 200 keV. A possible detection in the 200 keV - 500 keV band by SPI can not be confirmed with our observations. The normalization of the X/gamma-ray spectrum is (2.24 +/- 0.05) x 10(exp -2) photons /sq cm keV at 1 keV. The source showed a moderate amount of optical variability as observed with the OMC onboard INTEGRAL. No evidence for variability at X-rays and gamma-rays could be reported, which may have been a result of insufficient photon statistics. The X-/gamma-ray spectrum observed in our 2003 observations is consistent with previously measured and modelled broadband spectral energy distributions of 3C 273. It has been included in the U.S. lead Col's work on spectral and variability modelling of gamma-ray blazars, supporting the trend of flat-spectrum radio quasars such as 3C 273 being 7-ray dominated due to a strong contribution from Compton upscattering of external radiation by ultrarelativistic electrons in a relativistic jet. 3C 273 is a particularly convincing example for such a picture since it provides very direct evidence for a strong external radiation field by virtue of its obvious big blue bump, most likely originating in a very luminous accretion disk.

Cosmic X-ray physics

NASA Technical Reports Server (NTRS)

Mccammon, D.; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1985-01-01

A progress report of research activities carried out in the area of cosmic X-ray physics is presented. The Diffuse X-ray Spectrometer DXS which has been flown twice as a rocket payload is described. The observation times proved to be too small for meaningful X-ray data to be obtained. Data collection and reduction activities from the Ultra-Soft X-ray background (UXT) instrument are described. UXT consists of three mechanically-collimated X-ray gas proportional counters with window/filter combinations which allow measurements in three energy bands, Be (80-110 eV), B (90-187 eV), and O (e84-532 eV). The Be band measurements provide an important constraint on local absorption of X-rays from the hot component of the local interstellar medium. Work has also continued on the development of a calorimetric detector for high-resolution spectroscopy in the 0.1 keV - 8keV energy range.

Evidence for variability of the hard X-ray feature in the Hercules X-1 energy spectrum

NASA Technical Reports Server (NTRS)

Tueller, J.; Cline, T. L.; Teegarden, B. J.; Paciesas, W. S.; Boclet, D.; Durochoux, P.; Hameury, J. M.; Prantzos, N.; Haymes, R. C.

1983-01-01

The hard X-ray spectrum of HER X-1 was measured for the first time with a high resolution (1.4 keV FWHM) germanium spectrometer. The observation was performed near the peak of the on-state in the 35 day cycle and the 1.24 pulsations were observed between the energies of 20 keV and 70 keV. The feature corresponds to an excess of 7.5 sigma over the low energy continuum. Smooth continuum models are poor fits to the entire energy range (chance probabilities of 2 percent or less). The best fit energies are 35 keV for an absorption line and 39 keV for an emission line. These are significantly lower energies than those derived from previous experiments. A direct comparison of our data with the results of the MPI/AIT group shows statistically significant variations which strongly suggest variability in the source.

PheniX: A New Vision for the Hard X-ray Sky

NASA Technical Reports Server (NTRS)

Roques, Jean-Pierre; Jourdain, Elisabeth; Bassani, Loredana; Bazzano, Angela; Belmont, Renaud; Bird, A. J.; Caroli, E.; Chauvin, M.; Clark, D.; Gehrels, N.;

PheniX: a new vision for the hard X-ray sky

NASA Astrophysics Data System (ADS)

Roques, Jean-Pierre; Jourdain, Elisabeth; Bassani, Loredana; Bazzano, Angela; Belmont, Renaud; Bird, A. J.; Caroli, E.; Chauvin, M.; Clark, D.; Gehrels, N.; Goerlach, U.; Harrisson, F.; Laurent, P.; Malzac, J.; Medina, P.; Merloni, A.; Paltani, S.; Stephen, J.; Ubertini, P.; Wilms, J.

2012-10-01

We are proposing a mission devoted to high energy X-ray astronomy that is based on a focusing telescope operating in the 1-200 keV energy range but optimized for the hard X-ray range. The main scientific topics concern: Physics of compact objects: The proximity of compact objects provides a unique laboratory to study matter and radiation in extreme conditions of temperature and density in strong gravitational environment. The emission of high energy photons from these objects is far from being understood. The unprecedented sensitivity in the high energy domain will allow a precise determination of the non-thermal processes at work in the vicinity of compact objects. The full 1-200 keV energy coverage will be ideal to disentangle the emission processes produced in the spacetime regions most affected by strong-gravity, as well as the physical links: disk-thermal emission-iron line-comptonisation-reflection-non-thermal emission-jets. Neutron stars-magnetic field-cyclotron lines: Time resolved spectroscopy (and polarimetry) at ultra-high sensitivity of AXP, milliseconds pulsars and magnetars will give new tools to study the role of the synchrotron processes at work in these objects. Cyclotron lines-direct measurement of magnetic filed-equation of state constraints-short bursts-giant flares could all be studied with great details. AGN: The large sensitivity improvement will provide detailed spectral properties of the high energy emission of AGN's. This will give a fresh look to the connection between accretion and jet emission and will provide a new understanding of the physical processes at work. Detection of high-redshift active nuclei in this energy range will allow to introduce an evolutionary aspect to high-energy studies of AGN, probing directly the origin of the Cosmic X-ray Background also in the non-thermal range (> 20 keV). Element formation-Supernovae: The energy resolution achievable for this mission (<0.5 keV) and a large high energy effective area are ideally suited for the 44Ti line study (68 and 78 keV). This radioactive nuclei emission will give an estimate of their quantities and speed in their environment. In addition the study of the spatial structure and spectral emission of SNR will advance our knowledge of the dynamics of supernovae explosions, of particles acceleration mechanisms and how the elements are released in the interstellar medium. Instrumental design: The progress of X-ray focusing optics techniques allows a major step in the instrumental design: the collecting area becomes independent of the detection area. This drastically reduces the instrumental background and will open a new era. The optics will be based on depth-graded multi-layer mirrors in a Wolter I configuration. To obtain a significant effective area in the hundred of keV range a focal length in the 40-50 meters range (attainable with a deployable mast) is needed. In addition such a mission could benefit from recent progress made on mirror coating. We propose to cover the 1-200 keV energy range with a single detector, a double-sided Germanium strip detector operating at 80 K. The main features will be: (a) good energy resolution (.150 keV at 5 keV and <.5 keV at 100 keV), (b) 3 dimensional event localization with a low number of electronic chains, (c) background rejection by the 3D localization, (d) polarisation capabilities in the Compton regime.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodi, J.; Jourdain, E.; Roques, J. P., E-mail: jrodi@irap.omp.eu

The low-mass X-ray binary (LMXB) neutron star (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 spectramore » 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 Γ ∼ 2–3. GS 1826–238 was found to have a markedly different spectrum with kT{sub e} ∼ 20 keV and a hard tail dominating above ∼150 keV with an index of Γ ∼ 1.8, more similar to black hole X-ray binaries. We report on our search for long-term spectral variability over the 25–370 keV energy range and on a comparison of the GS 1826–238 average spectrum to the spectra of other LMXB NSs with hard tails.« less

Simulation of energy spectrum of GEM detector from an x-ray quantum

NASA Astrophysics Data System (ADS)

Malinowski, K.; Chernyshova, M.; Czarski, T.; Kowalska-Strzęciwilk, E.; Linczuk, P.; Wojeński, A.; Krawczyk, R.; Gąska, M.

2018-01-01

This paper presents the results of the energy resolution simulation for the triple GEM-based detector for x-ray quantum of 5.9 keV . Photons of this energy are emitted by 55Fe source, which is a standard calibration marker for this type of detectors. The calculations were made in Garfield++ in two stages. In the first stage, the distribution of the amount of primary electrons generated in the drift volume by the x-ray quantum was simulated using the Heed program. Secondly, the primary electrons of the resulting quantitative distribution were treated as a source of electron avalanches propagated through the whole volume of the triple GEM-based detector. The distribution of the obtained signals created a spectrum corresponding to the peak at 5.9 keV, which allowed us to determine the theoretical energy resolution of the detector. Its knowledge allows observing and improving the eventual experimental deterioration of the energy resolution, inevitably accompanying processes of registration and processing of the signals.

Simultaneous X-Ray, Gamma-Ray, and Radio Observations of the Repeating Fast Radio Burst FRB 121102

NASA Astrophysics Data System (ADS)

Scholz, P.; Bogdanov, S.; Hessels, J. W. T.; Lynch, R. S.; Spitler, L. G.; Bassa, C. G.; Bower, G. C.; Burke-Spolaor, S.; Butler, B. J.; Chatterjee, S.; Cordes, J. M.; Gourdji, K.; Kaspi, V. M.; Law, C. J.; Marcote, B.; McLaughlin, M. A.; Michilli, D.; Paragi, Z.; Ransom, S. M.; Seymour, A.; Tendulkar, S. P.; Wharton, R. S.

2017-09-01

We undertook coordinated campaigns with the Green Bank, Effelsberg, and Arecibo radio telescopes during Chandra X-ray Observatory and XMM-Newton observations of the repeating fast radio burst FRB 121102 to search for simultaneous radio and X-ray bursts. We find 12 radio bursts from FRB 121102 during 70 ks total of X-ray observations. We detect no X-ray photons at the times of radio bursts from FRB 121102 and further detect no X-ray bursts above the measured background at any time. We place a 5σ upper limit of 3 × 10‑11 erg cm‑2 on the 0.5–10 keV fluence for X-ray bursts at the time of radio bursts for durations < 700 ms, which corresponds to a burst energy of 4 × 1045 erg at the measured distance of FRB 121102. We also place limits on the 0.5–10 keV fluence of 5 × 10‑10 and 1 × 10‑9 erg cm‑2 for bursts emitted at any time during the XMM-Newton and Chandra observations, respectively, assuming a typical X-ray burst duration of 5 ms. We analyze data from the Fermi Gamma-ray Space Telescope Gamma-ray Burst Monitor and place a 5σ upper limit on the 10–100 keV fluence of 4 × 10‑9 erg cm‑2 (5 × 1047 erg at the distance of FRB 121102) for gamma-ray bursts at the time of radio bursts. We also present a deep search for a persistent X-ray source using all of the X-ray observations taken to date and place a 5σ upper limit on the 0.5–10 keV flux of 4 × 10‑15 erg s‑1 cm‑2 (3 × 1041 erg s‑1 at the distance of FRB 121102). We discuss these non-detections in the context of the host environment of FRB 121102 and of possible sources of fast radio bursts in general.

SphinX Measurements of the 2009 Solar Minimum X-Ray Emission

NASA Astrophysics Data System (ADS)

Sylwester, J.; Kowalinski, M.; Gburek, S.; Siarkowski, M.; Kuzin, S.; Farnik, F.; Reale, F.; Phillips, K. J. H.; Bakała, J.; Gryciuk, M.; Podgorski, P.; Sylwester, B.

2012-06-01

The SphinX X-ray spectrophotometer on the CORONAS-PHOTON spacecraft measured soft X-ray emission in the 1-15 keV energy range during the deep solar minimum of 2009 with a sensitivity much greater than GOES. Several intervals are identified when the X-ray flux was exceptionally low, and the flux and solar X-ray luminosity are estimated. Spectral fits to the emission at these times give temperatures of 1.7-1.9 MK and emission measures between 4 × 1047 cm-3 and 1.1 × 1048 cm-3. Comparing SphinX emission with that from the Hinode X-ray Telescope, we deduce that most of the emission is from general coronal structures rather than confined features like bright points. For one of 27 intervals of exceptionally low activity identified in the SphinX data, the Sun's X-ray luminosity in an energy range roughly extrapolated to that of ROSAT (0.1-2.4 keV) was less than most nearby K and M dwarfs.

Energy discriminating x-ray camera utilizing a cadmium telluride detector

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Purkhet, Abderyim; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Wantanabe, Manabu; Nagao, Jiro; Nomiya, Seiichiro; Hitomi, Keitaro; Tanaka, Etsuro; Kawai, Toshiaki; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2009-07-01

An energy-discriminating x-ray camera is useful for performing monochromatic radiography using polychromatic x rays. This x-ray camera was developed to carry out K-edge radiography using iodine-based contrast media. In this camera, objects are exposed by a cone beam from a cerium x-ray generator, and penetrating x-ray photons are detected by a cadmium telluride detector with an amplifier unit. The optimal x-ray photon energy and the energy width are selected out using a multichannel analyzer, and the photon number is counted by a counter card. Radiography was performed by the detector scanning using an x-y stage driven by a two-stage controller, and radiograms obtained by energy discriminating are shown on a personal computer monitor. In radiography, the tube voltage and current were 60 kV and 36 μA, respectively, and the x-ray intensity was 4.7 μGy/s. Cerium K-series characteristic x rays are absorbed effectively by iodine-based contrast media, and iodine K-edge radiography was performed using x rays with energies just beyond iodine K-edge energy 33.2 keV.

The Morphology of the X-ray Emission above 2 keV from Jupiter's Aurorae

NASA Technical Reports Server (NTRS)

Elsner, R.; Branduardi-Raymont, G.; Galand, M.; Grodent, D.; Gladstone, G. R.; Waite, J. H.; Cravens, T.; Ford, P.

2007-01-01

The discovery in XMM-Newton X-ray data of X-ray emission above 2 keY from Jupiter's aurorae has led us to reexamine the Chandra ACIS-S observations taken in Feb 2003. Chandra's superior spatial resolution has revealed that the auroral X-rays with E > 2 keV are emitted from the periphery of the region emitting those with E < 1 keV. We are presently exploring the relationship of this morphology to that of the FUV emission from the main auroral oval and the polar cap. The low energy emission has previously been established as due to charge exchange between energetic precipitating ions of oxygen and either sulfur or carbon. It seems likely to us that the higher energy emission is due to precipitation of energetic electrons, possibly the same population of electrons responsible for the FUV emission. We discuss our analysis and interpretation.

MODEL-INDEPENDENT LIMITS ON THE LINE-OF-SIGHT DEPTH OF CLUSTERS OF GALAXIES USING X-RAY AND SUNYAEV-ZEL'DOVICH DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahdavi, Andisheh; Chang Weihan

2011-07-01

We derive a model-independent expression for the minimum line-of-sight extent of the hot plasma in a cluster of galaxies. The only inputs are the 1-5 keV X-ray surface brightness and the Comptonization from Sunyaev-Zel'dovich (SZ) data. No a priori assumptions regarding equilibrium or geometry are required. The method applies when the X-ray emitting material has temperatures anywhere between 0.3 keV and 20 keV and metallicities between 0 and twice solar-conditions fulfilled by nearly all intracluster plasma. Using this method, joint APEX-SZ and Chandra X-ray Observatory data on the Bullet Cluster yield a lower limit of 400 {+-} 56 kpc onmore » the half-pressure depth of the main component, limiting it to being at least spherical, if not cigar-shaped primarily along the line of sight.« less

New Observations of Soft X-ray (0.5-5 keV) Solar Spectra

NASA Astrophysics Data System (ADS)

Caspi, A.; Woods, T. N.; Mason, J. P.; Jones, A. R.; Warren, H. P.

2013-12-01

The solar corona is the brightest source of X-rays in the solar system, and the X-ray emission is highly variable on many time scales. However, the actual solar soft X-ray (SXR) (0.5-5 keV) spectrum is not well known, particularly during solar quiet periods, as, with few exceptions, this energy range has not been systematically studied in many years. Previous observations include high-resolution but very narrow-band spectra from crystal spectrometers (e.g., Yohkoh/BCS), or integrated broadband irradiances from photometers (e.g., GOES/XRS, TIMED/XPS, etc.) that lack detailed spectral information. In recent years, broadband measurements with moderate energy resolution (~0.5-0.7 keV FWHM) were made by SphinX on CORONAS-Photon and SAX on MESSENGER, although they did not extend to energies below ~1 keV. We present observations of solar SXR emission obtained using new instrumentation flown on recent SDO/EVE calibration rocket underflights. The photon-counting spectrometer, a commercial Amptek X123 with a silicon drift detector and an 8 μm Be window, measures the solar disk-integrated SXR emission from ~0.5 to >10 keV with ~0.15 keV FWHM resolution and 1 s cadence. A novel imager, a pinhole X-ray camera using a cooled frame-transfer CCD (15 μm pixel pitch), Ti/Al/C filter, and 5000 line/mm Au transmission grating, images the full Sun in multiple spectral orders from ~0.1 to ~5 nm with ~10 arcsec/pixel and ~0.01 nm/pixel spatial and spectral detector scales, respectively, and 10 s cadence. These instruments are prototypes for future CubeSat missions currently being developed. We present new results of solar observations on 04 October 2013 (NASA sounding rocket 36.290). We compare with previous results from 23 June 2012 (NASA sounding rocket 36.286), during which solar activity was low and no signal was observed above ~4 keV. We compare our spectral and imaging measurements with spectra and broadband irradiances from other instruments, including SDO/EVE, GOES/XRS, TIMED/XPS, and RHESSI, as well as the SphinX observations during the deep solar minimum of 2009. Using newly-developed computational methods, we analyze the differential emission measure (DEM) of the solar corona, and discuss the possible implications for X-ray-producing physical processes in the quiescent corona.

Periodicity Analysis of X-ray Light Curves of SS 433

NASA Astrophysics Data System (ADS)

Wang, Jun-yi; Lu, Xiang-long; Zhao, Qiu-wen; Dong, Dian-qiao; Lao, Bao-qiang; Lu, Yang; Wei, Yan-heng; Wu, Xiao-cong; An, Tao

2017-01-01

SS 433 is sofar the unique X-ray binary that has the simultaneously detected orbital period, super-orbital period, and nutation period, as well as a bidirectional spiral jet. The study on its X-ray light variability is helpful for understanding the dynamic process of the system, and the correlations between the different wavebands. In this paper, two time-series analysis techniques, i.e., the Lomb-Scargle periodogram and weighted wavelet Z-transform, are employed to search for the periods in the Swift/BAT (Burst Alert Telescope) (15-50 keV) and RXTE/ASM (Rose X-ray Timing Explorer/All Sky Monitor) (1.5-3, 3- 4, and 5-12 keV) light curves of SS 433, and the Monte Carlo simulation is performed for the obtained periodical components. For the 15-50 keV energy band, five significant periodical components are detected, which are P1(∼6.29 d), P2 (∼6.54 d), P3 (∼13.08 d), P4 (∼81.50 d), and P5 (∼162.30 d). For the 3-5 and 5-12 keV energy bands, the periodical components P3 (∼13 d) and P5 (∼162 d) are detected in both energy bands. However, for the 1.5-3 keV energy band, no significant periodic signal is detected. P5 is the strongest periodic signal in the power spectrum for all the energy bands of 3-5, 5-12, and 15-50 keV, and it is consistent with the previous result obtained from the study of optical light curves. Furthermore, in combination with the radio spiral jet of SS 433, it is suggested that the X-ray and optical variability of P5 (∼162 d) is probably related to the precession of its relativistic jet. The high correlation between the X-ray and optical light curves may also imply that the X-ray and optical radiations are of the same physical origin. P3 shows a good agreement with the orbital period (∼13.07 d) obtained by the previous study, and P2 and P4 are respectively the high-frequency harmonics of P3 and P5. P1 is detected only in the power spectrum of the 15-50 keV energy band, and it is consistent with the nutation period of the system. As the energy of energy band decreases (from hard X-ray to soft X-ray), the number of detected periods becomes gradually less, this result verifies that the radiation in the high-energy band (hard X-ray) comes primarily from the jet, and the radiation in the low-energy band (soft X-ray) may be dominated by the medium around the binary system. The multiple X-ray periods obtained from the present study have provided a reliable basis for the further analysis of the multi-band data of SS 433, and the study on the dynamical mechanism of the system.

Chandra Reveals Heavy Obscuration and Circumnuclear Star Formation in Seyfert 2 Galaxy NGC 4968

NASA Astrophysics Data System (ADS)

LaMassa, Stephanie M.; Yaqoob, Tahir; Levenson, N. A.; Boorman, Peter; Heckman, Timothy M.; Gandhi, Poshak; Rigby, Jane R.; Urry, C. Megan; Ptak, Andrew F.

2017-01-01

We present the Chandra imaging and spectral analysis of NGC 4968, a nearby (z = 0.00986) Seyfert 2 galaxy. We discover extended (˜1 kpc) X-ray emission in the soft band (0.5-2 keV) that is neither coincident with the narrow line region nor the extended radio emission. Based on spectral modeling, it is linked to on-going star formation (˜2.6-4 M⊙ yr-1). The soft emission at circumnuclear scales (inner ˜400 pc) originates from hot gas, with kT ˜ 0.7 keV, while the most extended thermal emission is cooler (kT ˜ 0.3 keV). We refine previous measurements of the extreme Fe Kα equivalent width in this source ({EW}={2.5}-1.0+2.6 {keV}), which suggests the central engine is completely embedded within Compton-thick levels of obscuration. Using physically motivated models fit to the Chandra spectrum, we derive a Compton-thick column density (NH > 1.25 × 1024 cm-2) and an intrinsic hard (2-10 keV) X-ray luminosity of ˜3-8 × 1042 erg s-1 (depending on the presumed geometry of the obscurer), which is over two orders of magnitude larger than that observed. The large Fe Kα EW suggests a spherical covering geometry, which could be confirmed with X-ray measurements above 10 keV. NGC 4968 is similar to other active galaxies that exhibit extreme Fe Kα EWs (I.e., >2 keV) in that they also contain on-going star formation. This work supports the idea that gas associated with nuclear star formation may increase the covering factor of the enshrouding gas and play a role in obscuring active galactic nuclei.

System for phase-contrast x-ray radiography using X pinch radiation and a method thereof

DOEpatents

Chandler, Katherine; Chelkovenko, Tatiana; Hammer, David; Pikuz, Sergei; Sinars, Daniel; Song, Byungmoo

2007-11-06

A radiograph system with an anode plate, a cathode plate, and a power source coupled to said anode plate and the cathode plate. At least two wires coupled between the anode plate and the cathode plate provide a configuration to form an X-pinch having a photon source size of less than five microns at energies above 2.5 keV. Material at the configuration forming the X-pinch vaporizes upon application of a suitable current to the wires forming a dense hot plasma and emitting a single x-ray pulse with sufficient photons having energies in the range of from about 2.5 keV to about 20 keV to provide a phase contrast image of an object in the path of the photons. Multiple simultaneous images may be formed of a plurality of objects. Suitable filters and x-ray detectors are provided.

X-Rays from the Explosion Site: Fifteen Years of Light Curves of SN 1993J

NASA Technical Reports Server (NTRS)

Chandra, Poonam; Dwarkadas, Vikram V.; Ray, Alak; Immler, Stefan; Pooley, David

2009-01-01

We present a comprehensive analysis of the X-ray light curves of SN 1993J in a nearby galaxy M81. This is the only supernova other than SN 1987A, which is so extensively followed in the X-ray bands. Here we report on SN 1993J observations with the Chandra in the year 2005 and 2008, and Swift observations in 2005, 2006 and 2008. We combined these observations with all available archival data of SN 1993J, which includes ROSAT, ASCA, Chandra, and XMM-Newton, observations from 1993 April to 2006 August. In this paper we report the X-ray light curves of SN 1993J, extending up to fifteen years, in the soft (0.3-2.4 keV), hard (2-8 keV) and combined (0.3-8 keV) bands. The hard and soft-band fluxes decline at different rates initially, but after about 5 years they both undergo a t(sup -1) decline. The soft X-rays, which are initially low, start dominating after a few hundred days. We interpret that most of the emission below 8 keV is coming from the reverse shock which is radiative initially for around first 1000-2000 days and then turn into adiabatic shock. Our hydrodynamic simulation also confirms the reverse shock origin of the observed light curves. We also compare the Ha line luminosity of SN 1993J with its X-ray light curve and note that the Ha line luminosity has a fairly high fraction of the X-ray emission, indicating presence of clumps in the emitting plasma.

A compact and high efficiency GAGG well counter for radiocesium concentration measurements

NASA Astrophysics Data System (ADS)

Yamamoto, Seiichi; Ogata, Yoshimune

2014-07-01

After the Fukushima nuclear disaster, social concern about radiocesium (137Cs and 134Cs) contamination in food increased. However, highly efficient instruments that can measure low level radioactivity are quite expensive and heavy. A compact, lightweight, and reliable radiation detector that can inexpensively monitor low level radiocesium is highly desired. We developed a compact and highly efficient radiocesium detector to detect ~32 keV X-rays from radiocesium instead of high energy gamma photons. A 1-mm thick GAGG scintillator was selected to effectively detect ~32 keV X-rays from 137Cs to reduce the influence of ambient radiation. Four sets of 25 mm×25 mm×1 mm GAGG plates, each of which was optically coupled to a triangular-shaped light guide, were optically coupled to a photomultiplier tube (PMT) to form a square-shaped well counter. Another GAGG plate was directly optically coupled to the PMT to form its bottom detector. The energy resolution of the GAGG well counter was 22.3% FWHM for 122 keV gamma rays and 32% FWHM for ~32 keV X-rays. The counting efficiency for the X-rays from radiocesium (mixture of 137Cs and 134Cs) was 4.5%. In measurements of the low level radiocesium mixture, a photo-peak of ~32 keV X-rays can clearly be distinguished from the background. The minimum detectable activity (MDA) was estimated to be ~100 Bq/kg for 1000 s measurement. The results show that our developed GAGG well counter is promising for the detection of radiocesium in food.

Measured reflectance of graded multilayer mirrors designed for astronomical hard X-ray telescopes

NASA Astrophysics Data System (ADS)

Christensen, F. E.; Craig, W. W.; Windt, D. L.; Jimenez-Garate, M. A.; Hailey, C. J.; Harrison, F. A.; Mao, P. H.; Chakan, J. M.; Ziegler, E.; Honkimaki, V.

2000-09-01

Future astronomical X-ray telescopes, including the balloon-borne High-Energy Focusing Telescope (HEFT) and the Constellation-X Hard X-ray Telescope (Con-X HXT) plan to incorporate depth-graded multilayer coatings in order to extend sensitivity into the hard X-ray (10<~E<~80keV) band. In this paper, we present measurements of the reflectance in the 18-170 keV energy range of a cylindrical prototype nested optic taken at the European Synchrotron Radiation Facility (ESRF). The mirror segments, mounted in a single bounce stack, are coated with depth-graded W/Si multilayers optimized for broadband performance up to 69.5 keV (WK-edge). These designs are ideal for both the HEFT and Con-X HXT applications. We compare the measurements to model calculations to demonstrate that the reflectivity can be well described by the intended power law distribution of the bilayer thicknesses, and that the coatings are uniform at the 5% level over the mirror surface. Finally, we apply the measurements to predict effective areas achievable for HEFT and Con-X HXT using these W/Si designs.

X-ray source for mammography

DOEpatents

Logan, C.M.

1994-12-20

An x-ray source is described utilizing anode material which shifts the output spectrum to higher energy and thereby obtains higher penetrating ability for screening mammography application, than the currently utilized anode material. The currently used anode material (molybdenum) produces an energy x-ray spectrum of 17.5/19.6 keV, which using the anode material of this invention (e.g. silver, rhodium, and tungsten) the x-ray spectrum would be in the 20-35 keV region. Thus, the anode material of this invention provides for imaging of breasts with higher than average x-ray opacity without increase of the radiation dose, and thus reduces the risk of induced breast cancer due to the radiation dose administered for mammograms. 6 figures.

Comparison of simulated and measured spectra from an X-ray tube for the energies between 20 and 35 keV

NASA Astrophysics Data System (ADS)

Yücel, M.; Emirhan, E.; Bayrak, A.; Ozben, C. S.; Yücel, E. Barlas

2015-11-01

Design and production of a simple and low cost X-ray imaging system that can be used for light industrial applications was targeted in the Nuclear Physics Laboratory of Istanbul Technical University. In this study, production, transmission and detection of X-rays were simulated for the proposed imaging device. OX/70-P dental tube was used and X-ray spectra simulated by Geant4 were validated by comparison with X-ray spectra measured between 20 and 35 keV. Relative detection efficiency of the detector was also determined to confirm the physics processes used in the simulations. Various time optimization tools were performed to reduce the simulation time.

a-Si:H TFT-silicon hybrid low-energy x-ray detector

DOE PAGES

Shin, Kyung -Wook; Karim, Karim S.

2017-03-15

Direct conversion crystalline silicon X-ray imagers are used for low-energy X-ray photon (4-20 keV) detection in scientific research applications such as protein crystallography. In this paper, we demonstrate a novel pixel architecture that integrates a crystalline silicon X-ray detector with a thin-film transistor amorphous silicon pixel readout circuit. We describe a simplified two-mask process to fabricate a complete imaging array and present preliminary results that show the fabricated pixel to be sensitive to 5.89-keV photons from a low activity Fe-55 gamma source. Furthermore, this paper presented can expedite the development of high spatial resolution, low cost, direct conversion imagers formore » X-ray diffraction and crystallography applications.« less

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

NASA Technical Reports Server (NTRS)

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

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

NASA Astrophysics Data System (ADS)

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.

Self-modulated laser wakefield accelerators as x-ray sources

DOE PAGES

Lemos, N.; Martins, J. L.; Tsung, F. S.; ...

2016-02-17

The development of a directional, small-divergence, and short-duration picosecond x-ray probe beam with an energy greater than 50 keV is desirable for high energy density science experiments. We therefore explore through particle-in-cell (PIC) computer simulations the possibility of using x-rays radiated by betatron-like motion of electrons from a self-modulated laser wakefield accelerator as a possible candidate to meet this need. Two OSIRIS 2D PIC simulations with mobile ions are presented, one with a normalized vector potential a 0 = 1.5 and the other with an a 0 = 3. We find that in both cases direct laser acceleration (DLA) ismore » an important additional acceleration mechanism in addition to the longitudinal electric field of the plasma wave. Together these mechanisms produce electrons with a continuous energy spectrum with a maximum energy of 300 MeV for a 0 = 3 case and 180 MeV in the a 0 = 1.5 case. Forward-directed x-ray radiation with a photon energy up to 100 keV was calculated for the a 0 = 3 case and up to 12 keV for the a 0 = 1.5 case. The x-ray spectrum can be fitted with a sum of two synchrotron spectra with critical photon energies of 13 and 45 keV for the a 0 of 3 and critical photon energies of 0.3 and 1.4 keV for a 0 of 1.5 in the plane of polarization of the laser. As a result, the full width at half maximum divergence angle of the x-rays was 62 × 1.9 mrad for a 0 = 3 and 77 × 3.8 mrad for a 0 = 1.5.« less

Bright end of the luminosity function of high-mass X-ray binaries: contributions of hard, soft and supersoft sources

NASA Astrophysics Data System (ADS)

Sazonov, S.; Khabibullin, I.

2017-04-01

Using a spectral analysis of bright Chandra X-ray sources located in 27 nearby galaxies and maps of star-formation rate (SFR) and interstellar medium surface densities for these galaxies, we constructed the intrinsic X-ray luminosity function (XLF) of luminous high-mass X-ray binaries (HMXBs), taking into account absorption effects and the diversity of HMXB spectra. The XLF per unit SFR can be described by a power-law dN/dlog LX,unabs ≈ 2.0(LX,unabs/1039 erg s-1)-0.6 (M⊙ yr-1)-1 from LX,unabs = 1038 to 1040.5 erg s-1, where LX,unabs is the unabsorbed luminosity at 0.25-8 keV. The intrinsic number of luminous HMXBs per unit SFR is a factor of ˜2.3 larger than the observed number reported before. The intrinsic XLF is composed of hard, soft and supersoft sources (defined here as those with the 0.25-2 keV to 0.25-8 keV flux ratio of <0.6, 0.6-0.95 and >0.95, respectively) in ˜ 2:1:1 proportion. We also constructed the intrinsic HMXB XLF in the soft X-ray band (0.25-2 keV). Here, the numbers of hard, soft and supersoft sources prove to be nearly equal. The cumulative present-day 0.25-2 keV emissivity of HMXBs with luminosities between 1038 and 1040.5 erg s-1 is ˜5 × 1039 erg s-1(M⊙ yr-1)-1, which may be relevant for studying the X-ray preheating of the early Universe.

The high energy X-ray spectrum of 4U 1700-37 observed from OSO 8

NASA Technical Reports Server (NTRS)

Dolan, J. F.; Coe, M. J.; Crannell, C. J.; Dennis, B. R.; Frost, K. J.; Orwig, L. E.; Maurer, G. S.

1980-01-01

The most intense hard X-ray source in the confused region in Scorpius has been identified as 4U 1700-37 (=HD 153919). Observations extending over three binary periods in 1978 September were carried out with the high-energy X-ray spectrometer on OSO 8. The 3.4 day modulation is seen above 20 keV with the intensity during eclipse being consistent with zero flux. The photonumber spectrum from 20 to 150 keV is well represented by a single power law with a photonumber spectral index of -2.77 + or - 0.35 or by a thermal bremsstrahlung spectrum with kT = 27 (+15, -7)keV. The counting rate above 20 keV outside of eclipse shows no evidence for the 96.8 minute X-ray modulation previously reported at lower energies. Despite the difficulties that exist in reconciling both the lack of periodic modulation in the emitted X-radiation and the orbital dynamics of the system with our currently accepted theories of the evolution and physical properties of neutron stars, the observed properties of 4U 1700-37 are all consistent with the source being a spherically accreting neutron star rather than a black hole.

Inferred UV Fluence Focal-Spot Profiles from Soft X-Ray Pinhole Camera Measurements on OMEGA

NASA Astrophysics Data System (ADS)

Theobald, W.; Sorce, C.; Epstein, R.; Keck, R. L.; Kellogg, C.; Kessler, T. J.; Kwiatkowski, J.; Marshall, F. J.; Seka, W.; Shvydky, A.; Stoeckl, C.

2017-10-01

The drive uniformity of OMEGA cryogenic implosions is affected by UV beamfluence variations on target, which require careful monitoring at full laser power. This is routinely performed with multiple pinhole cameras equipped with charge-injection devices (CID's) that record the x-ray emission in the 3- to 7-keV photon energy range from an Au-coated target. The technique relies on the knowledge of the relation between x-ray fluence Fx and UV fluence FUV ,Fx FUVγ , with a measured γ = 3.42 for the CID-based diagnostic and 1-ns laser pulse. It is demonstrated here that using a back-thinned charge-coupled-device camera with softer filtration for x-rays with photon energies <2 keV and well calibrated pinhole provides a lower γ 2 and a larger dynamic range in the measured UV fluence. Inferred UV fluence profiles were measured for 100-ps and 1-ns laser pulses and were compared to directly measured profiles from a UV equivalent-target-plane diagnostic. Good agreement between both techniques is reported for selected beams. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

Measurement of Kα and Kβ fluorescence cross sections for elements in the range 44<=Z<=68 at 59.5 keV

NASA Astrophysics Data System (ADS)

Budak, G.; Karabulut, A.; Demir, L.; Sahin, Y.

1999-09-01

The Kα and Kβ x-ray fluorescence cross sections have been measured for elements in the range 44<=Z<=68 at an excitation energy of 59.5-keV γ ray from 241Am radioisotope with a Si(Li) detector. A reasonable agreement is found between the present experimental results and the theoretically calculated values based on photoionization cross sections by Scofield using Hartree-Slater and Hartree-Fock central potential theory.

Submicron hard X-ray fluorescence imaging of synthetic elements.

PubMed

Jensen, Mark P; Aryal, Baikuntha P; Gorman-Lewis, Drew; Paunesku, Tatjana; Lai, Barry; Vogt, Stefan; Woloschak, Gayle E

2012-04-13

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 μ-XANES (X-ray absorption near edge structure). We have used XFM to image and simultaneously quantify the transuranic element plutonium at the L(3) or L(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 (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 μm(2) cell is 1.4 fg Pu or 2.9×10(-20) moles Pu μm(-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(α) X-ray emission. Copyright © 2012 Elsevier B.V. All rights reserved.

BEaTriX, expanded x-ray beam facility for testing modular elements of telescope optics: an update

NASA Astrophysics Data System (ADS)

Pelliciari, C.; Spiga, D.; Bonnini, E.; Buffagni, E.; Ferrari, C.; Pareschi, G.; Tagliaferri, G.

2015-09-01

We present in this paper an update on the design of BEaTriX (Beam Expander Testing X-ray facility), an X-ray apparatus to be realized at INAF/OAB and that will generate an expanded, uniform and parallel beam of soft X-rays. BEaTriX will be used to perform the functional tests of X-ray focusing modules of large X-ray optics such as those for the ATHENA X-ray observatory, using the Silicon Pore Optics (SPO) as a baseline technology, and Slumped Glass Optics (SGO) as a possible alternative. Performing the tests in X-rays provides the advantage of an in-situ, at-wavelength quality control of the optical modules produced in series by the industry, performing a selection of the modules with the best angular resolution, and, in the case of SPOs, there is also the interesting possibility to align the parabolic and the hyperbolic stacks directly under X-rays, to minimize the aberrations. However, a parallel beam with divergence below 2 arcsec is necessary in order to measure mirror elements that are expected to reach an angular resolution of about 4 arcsec, since the ATHENA requirement for the entire telescope is 5 arcsec. Such a low divergence over the typical aperture of modular optics would require an X-ray source to be located in a several kilometers long vacuum tube. In contrast, BEaTriX will be compact enough (5 m x 14 m) to be housed in a small laboratory, will produce an expanded X-ray beam 60 mm x 200 mm broad, characterized by a very low divergence (1.5 arcsec HEW), strong polarization, high uniformity, and X-ray energy selectable between 1.5 keV and 4.5 keV. In this work we describe the BEaTriX layout and show a performance simulation for the X-ray energy of 4.5 keV.

Synchrotron X-ray studies of the keel of the short-spined sea urchin Lytechinus variegatus: absorption microtomography (microCT) and small beam diffraction mapping.

PubMed

Stock, S R; Barss, J; Dahl, T; Veis, A; Almer, J D; Carlo, F

2003-05-01

In sea urchin teeth, the keel plays an important structural role, and this paper reports results of microstructural characterization of the keel of Lytechinus variegatus using two noninvasive synchrotron x-ray techniques: x-ray absorption microtomography (microCT) and x-ray diffraction mapping. MicroCT with 14 keV x-rays mapped the spatial distribution of mineral at the 1.3 microm level in a millimeter-sized fragment of a mature portion of the keel. Two rows of low absorption channels (i.e., primary channels) slightly less than 10 microm in diameter were found running linearly from the flange to the base of the keel and parallel to its sides. The primary channels paralleled the oral edge of the keel, and the microCT slices revealed a planar secondary channel leading from each primary channel to the side of the keel. The primary and secondary channels were more or less coplanar and may correspond to the soft tissue between plates of the carinar process. Transmission x-ray diffraction with 80.8 keV x-rays and a 0.1 mm beam mapped the distribution of calcite crystal orientations and the composition Ca(1-x)Mg(x)CO(3) of the calcite. Unlike the variable Mg concentration and highly curved prisms found in the keel of Paracentrotus lividus, a constant Mg content (x = 0.13) and relatively little prism curvature was found in the keel of Lytechinus variegatus.

Measurement of X-ray mass attenuation coefficients in biological and geological samples in the energy range of 7-12keV.

PubMed

Trunova, Valentina; Sidorina, Anna; Kriventsov, Vladimir

2015-01-01

Information about X-ray mass attenuation coefficients in different materials is necessary for accurate X-ray fluorescent analysis. The X-ray mass attenuation coefficients for energy of 7-12keV were measured in biological (Mussel and Oyster tissues, blood, hair, liver, and Cabbage leaves) and geological (Baikal sludge, soil, and Alaskite granite) samples. The measurements were carried out at the EXAFS Station of Siberian Synchrotron Radiation Center (VEPP-3). Obtained experimental mass attenuation coefficients were compared with theoretical values calculated for some samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

X-ray Full Field Microscopy at 30 keV

NASA Astrophysics Data System (ADS)

Marschall, F.; Last, A.; Simon, M.; Kluge, M.; Nazmov, V.; Vogt, H.; Ogurreck, M.; Greving, I.; Mohr, J.

2014-04-01

In our X-ray full field microscopy experiments, we demonstrated a resolution better than 260 nm over the entire field of view of 80 μm × 80 μm at 30 keV. Our experimental setup at PETRA III, P05, had a length of about 5 m consisting of an illumination optics, an imaging lens and a detector. For imaging, we used a compound refractive lens (CLR) consisting of mr-L negative photo resist, which was fabricated by deep X-ray lithography. As illumination optics, we choose a refractive rolled X-ray prism lens, which was adapted to the numerical aperture of the imaging lens.

Recent progress of hard x-ray imaging microscopy and microtomography at BL37XU of SPring-8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Yoshio, E-mail: yoshio@spring8.or.jp; Takeuchi, Akihisa; Terada, Yasuko

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.

High energy X-ray observations of COS-B gamma-ray sources from OSO-8

NASA Technical Reports Server (NTRS)

Dolan, J. F.; Crannell, C. J.; Dennis, B. R.; Frost, K. J.; Orwig, L. E.; Caraveo, P. A.

1985-01-01

During the three years between satellite launch in June 1975 and turn-off in October 1978, the high energy X-ray spectrometer on board OSO-8 observed nearly all of the COS-B gamma-ray source positions given in the 2CG catalog (Swanenburg et al., 1981). An X-ray source was detected at energies above 20 keV at the 6-sigma level of significance in the gamma-ray error box containing 2CG342 - 02 and at the 3-sigma level of significance in the error boxes containing 2CG065 + 00, 2CG195 + 04, and 2CG311 - 01. No definite association between the X-ray and gamma-ray sources can be made from these data alone. Upper limits are given for the 2CG sources from which no X-ray flux was detected above 20 keV.

Search for X rays from the planet Jupiter.

NASA Technical Reports Server (NTRS)

Hurley, K. C.

1972-01-01

Actively collimated balloon-borne scintillation counters employing a special phoswich anticoincidence technique were flown a total of 5 times from Palestine, Texas. Jupiter was observed for a total of 133 min, and an upper limit to the flux of X rays present at the observation time is .016 X rays/sq cm sec in the energy range 30-100 keV. Three separate calculations are made to estimate the flux of Jovian X rays at the earth. These estimates range from .000000001 to .1 X rays/sq cm sec in the energy range 30-100 keV. It is concluded that, since there was no decametric emission at the time of the flight and there had been no significant solar activity for several days prior to the flight, no X rays were being generated at the time of the observation.

Omega Dante soft x-ray power diagnostic component calibration at the National Synchrotron Light Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, K.M.; Weber, F.A.; Dewald, E.L.

2004-10-01

The Dante soft x-ray spectrometer, installed on the Omega laser facility at the Laboratory for Laser Energetics, University of Rochester, is a 12-channel filter-edge defined soft x-ray power diagnostic. It is used to measure the spectrally resolved, absolute flux from direct drive, indirect drive (hohlraums) and other plasma sources. Dante component calibration efforts using two beam lines, U3C (50 eV-1 keV) and X8A (1-6 keV) at the National Synchrotron Light Source have been implemented to improve the accuracy of these measurements. We have calibrated metallic vacuum x-ray diodes, mirrors and filters.

Determination of natural line widths of Kα X-ray lines for some elements in the atomic range 50≤Z≤65 at 59.5 keV

NASA Astrophysics Data System (ADS)

Kündeyi, Kadriye; Aylıkcı, Nuray Küp; Tıraşoǧlu, Engin; Kahoul, Abdelhalim; Aylıkcı, Volkan

2017-02-01

The semi-empirical determination of natural widths of Kα X-ray lines (Kα1 and Kα2) were performed for Sn, Sb, Te, I, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd and Tb. For the semi-empirical determination of the line widths, K shell fluorescence yields of elements were measured. The samples were excited by 59.5 keV γ rays from a 241Am annular radioactive source in order to measure the K shell fluorescence yields. The emitted K X-rays from the samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The measured K shell fluorescence yields were used for the calculation of K shell level widths. Finally, the natural widths of K X-ray lines were determined as the sums of levels which involved in the transition. The obtained values were compared with earlier studies.

A first evaluation of the analytical capabilities of the new X-ray fluorescence facility at International Atomic Energy Agency-Elettra Sincrotrone Trieste for multipurpose total reflection X-ray fluorescence analysis

NASA Astrophysics Data System (ADS)

Marguí, Eva; Hidalgo, Manuela; Migliori, Alessandro; Leani, Juan José; Queralt, Ignasi; Kallithrakas-Kontos, Nikolaos; Streli, Christina; Prost, Josef; Karydas, Andreas Germanos

2018-07-01

The aim of the work is to present a systematic evaluation of the analytical capabilities of the new X-ray fluorescence facility jointly operated between the International Atomic Energy Agency and the Elettra Sincrotrone Trieste for multipurpose total reflection X-ray fluorescence analysis. The analytical performance of the XRF beamline end-station (IAEAXspe) was systematically evaluated under TXRF excitation geometry by analyzing different types of aqueous (lake, waste and fresh water) and solid (soil, vegetal, biological) certified reference materials using an excitation energy of 13.0 keV (for the purpose of multielemental analysis). The results obtained for both types of samples in terms of limits of detection and accuracy were also compared with those obtained using laboratory X-ray tube based TXRF systems with different features (including Mo and W X-ray tube systems). Taking advantage of the possibility to work under high vacuum, the IAEAXspe set-up instrumental sensitivity was also determined using an excitation energy of 6.2 keV to explore the possibilities for light elements determination. A clear improvement of the element detection limits is achieved when comparing this facility to conventional X-ray tube based TXRF systems highlighting the benefits of using the monoenergetic synchrotron exciting radiation and the ultra-high vacuum chamber in comparison with conventional laboratory systems. The results of the present work are discussed in view of further exploitation of the facility for different environmental and biological related applications.

The Chandra COSMOS-Legacy Survey: Source X-Ray Spectral Properties

NASA Astrophysics Data System (ADS)

Marchesi, S.; Lanzuisi, G.; Civano, F.; Iwasawa, K.; Suh, H.; Comastri, A.; Zamorani, G.; Allevato, V.; Griffiths, R.; Miyaji, T.; Ranalli, P.; Salvato, M.; Schawinski, K.; Silverman, J.; Treister, E.; Urry, C. M.; Vignali, C.

2016-10-01

We present the X-ray spectral analysis of the 1855 extragalactic sources in the Chandra COSMOS-Legacy survey catalog having more than 30 net counts in the 0.5-7 keV band. A total of 38% of the sources are optically classified type 1 active galactic nuclei (AGNs), 60% are type 2 AGNs, and 2% are passive, low-redshift galaxies. We study the distribution of AGN photon index Γ and of the intrinsic absorption {N}{{H},{{z}}} based on the sources’ optical classification: type 1 AGNs have a slightly steeper mean photon index Γ than type 2 AGNs, which, on the other hand, have average {N}{{H},{{z}}} ˜ 3 times higher than type 1 AGNs. We find that ˜15% of type 1 AGNs have {N}{{H},{{z}}}\\gt {10}22 cm-2, I.e., are obscured according to the X-ray spectral fitting; the vast majority of these sources have {L}2{--10{keV}} \\gt 1044 erg s-1. The existence of these objects suggests that optical and X-ray obscuration can be caused by different phenomena, the X-ray obscuration being, for example, caused by dust-free material surrounding the inner part of the nuclei. Approximately 18% of type 2 AGNs have {N}{{H},{{z}}}\\lt {10}22 cm-2, and most of these sources have low X-ray luminosities (L {}2{--10{keV}} \\lt 1043 erg s-1). We expect a part of these sources to be low-accretion, unobscured AGNs lacking broad emission lines. Finally, we also find a direct proportional trend between {N}{{H},{{z}}} and host-galaxy mass and star formation rate, although part of this trend is due to a redshift selection effect.

Direct measurement of mammographic X-ray spectra with a digital CdTe detection system.

PubMed

Abbene, Leonardo; Gerardi, Gaetano; Principato, Fabio; Del Sordo, Stefano; Raso, Giuseppe

2012-01-01

In this work we present a detection system, based on a CdTe detector and an innovative digital pulse processing (DPP) system, for high-rate X-ray spectroscopy in mammography (1-30 keV). The DPP system performs a height and shape analysis of the detector pulses, sampled and digitized by a 14-bit, 100 MHz ADC. We show the results of the characterization of the detection system both at low and high photon counting rates by using monoenergetic X-ray sources and a nonclinical X-ray tube. The detection system exhibits excellent performance up to 830 kcps with an energy resolution of 4.5% FWHM at 22.1 keV. Direct measurements of clinical molybdenum X-ray spectra were carried out by using a pinhole collimator and a custom alignment device. A comparison with the attenuation curves and the half value layer values, obtained from the measured and simulated spectra, from an ionization chamber and from a solid state dosimeter, also shows the accuracy of the measurements. These results make the proposed detection system a very attractive tool for both laboratory research, calibration of dosimeters and advanced quality controls in mammography.

Relative efficiency calibration between two silicon drift detectors performed with a monochromatized X-ray generator over the 0.1-1.5 keV range

NASA Astrophysics Data System (ADS)

Hubert, S.; Boubault, F.

2018-03-01

In this article, we present the first X-ray calibration performed over the 0.1-1.5 keV spectral range by means of a soft X-ray Manson source and the monochromator SYMPAX. This monochromator, based on a classical Rowland geometry, presents the novelty to be able to board simultaneously two detectors and move them under vacuum in front of the exit slit of the monochromatizing stage. This provides the great advantage to perform radiometric measurements of the monochromatic X-ray photon flux with one reference detector while calibrating another X-ray detector. To achieve this, at least one secondary standard must be operated with SYMPAX. This paper presents thereby an efficiency transfer experiment between a secondary standard silicon drift detector (SDD), previously calibrated on BESSY II synchrotron Facility, and another one ("unknown" SDD), devoted to be used permanently with SYMPAX. The associated calibration process is described as well as corresponding results. Comparison with calibrated measurements performed at the Physikalisch-Technische Bundesanstalt (PTB) Radiometric Laboratory shows a very good agreement between the secondary standard and the unknown SDD.

The MIT HEDP Accelerator Facility for Diagnostic Development for OMEGA, Z, and the NIF

NASA Astrophysics Data System (ADS)

Sio, H.; Gatu Johnson, M.; Birkel, A.; Doeg, E.; Frankel, R.; Kabadi, N. V.; Lahmann, B.; Manzin, M.; Simpson, R. A.; Parker, C. E.; Sutcliffe, G. D.; Wink, C.; Frenje, J. A.; Li, C. K.; Seguin, F. H.; Petrasso, R. D.; Leeper, R.; Hahn, K.; Ruiz, C. L.; Sangster, T. C.; Hilsabeck, T.

2017-10-01

The MIT HEDP Accelerator Facility utilizes a 135-keV, linear electrostatic ion accelerator; DT and DD neutron sources; and two x-ray sources for development and characterization of nuclear diagnostics for OMEGA, Z, and the NIF. The accelerator generates DD and D3He fusion products through the acceleration of D+ ions onto a 3He-doped Erbium-Deuteride target. Accurately characterized fusion product rates of around 106 s- 1 are routinely achieved. The DT and DD neutron sources generate up to 6×108 and 1×107 neutrons/s, respectively. One x-ray generator is a thick-target W source with a peak energy of 225 keV and a maximum dose rate of 12 Gy/min; the other uses Cu, Mo, or Ti elemental tubes to generate x-rays with a maximum energy of 40 keV. Diagnostics developed and calibrated at this facility include CR-39-based charged-particle spectrometers, neutron detectors, and the particle Time-Of-Flight (pTOF) and Magnetic PTOF CVD-diamond-based bang time detectors. The accelerator is also a valuable hands-on tool for graduate and undergraduate education at MIT. This work was supported in part by the U.S. DoE, SNL, LLE and LLNL.

Electromagnetic diagnostics of ECR-Ion Sources plasmas: optical/X-ray imaging and spectroscopy

NASA Astrophysics Data System (ADS)

Mascali, D.; Castro, G.; Altana, C.; Caliri, C.; Mazzaglia, M.; Romano, F. P.; Leone, F.; Musumarra, A.; Naselli, E.; Reitano, R.; Torrisi, G.; Celona, L.; Cosentino, L. G.; Giarrusso, M.; Gammino, S.

2017-12-01

Magnetoplasmas in ECR-Ion Sources are excited from gaseous elements or vapours by microwaves in the range 2.45-28 GHz via Electron Cyclotron Resonance. A B-minimum, magnetohydrodynamic stable configuration is used for trapping the plasma. The values of plasma density, temperature and confinement times are typically ne= 1011-1013 cm-3, 01 eV

The reawakening of the sleeping X-ray pulsar XTE J1946+274

NASA Astrophysics Data System (ADS)

Müller, S.; Kühnel, M.; Caballero, I.; Pottschmidt, K.; Fürst, F.; Kreykenbohm, I.; Sagredo, M.; Obst, M.; Wilms, J.; Ferrigno, C.; Rothschild, R. E.; Staubert, R.

2012-10-01

We report on a series of outbursts of the high-mass X-ray binary XTE J1946+274 in 2010/2011 observed with INTEGRAL, RXTE, and Swift. We discuss possible mechanisms resulting in the extraordinary outburst behavior of this source. The X-ray spectra can be described by standard phenomenological models, enhanced by an absorption feature of unknown origin at about 10 keV and a narrow iron Kα fluorescence line at 6.4 keV, which are variable in flux and pulse phase. We find possible evidence for a cyclotron resonance scattering feature at about 25 keV at the 93% level. The presence of a strong cyclotron line at 35 keV seen in data from the source's 1998 outburst that was confirmed by a reanalysis of these data can be excluded. This result indicates that the cyclotron line feature in XTE J1946+274 is variable between individual outbursts.

The Reawakening of the Sleeping X-ray Pulsar XTE J1946+274

NASA Technical Reports Server (NTRS)

Mueller, Sebastian; Mueller, Sebastian; Kuechnel, Matthias; Fuerst, Felix; Kreykenbohm, Ingo; Sagredo, Macarena; Obst, Maria; Wilms, Joern; Caballero, Isabel; Potttschmidt, Katja;

The Variable Hard X-Ray Emission of NGC4945 as Observed by NuSTAR

NASA Technical Reports Server (NTRS)

Puccetti, Simonetta; Comastri, Andrea; Fiore, Fabrizio; Arevalo, Patricia; Risaliti, Guido; Bauer, Franz E.; Brandt, William N.; Stern, Daniel; Harrison, Fiona A.; Alexander, David M.;

The Variable Hard X-Ray Emission of NGC 4945 as Observed by NUSTAR

DOE PAGES

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

2014-09-02

Here, 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 τThomson ~more » 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 λEdd depending on the flux state. As a result, 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 Edd values for obscured AGNs.« less

The Hard X-ray Imager (HXI) for the ASTRO-H Mission

NASA Astrophysics Data System (ADS)

Sato, Goro; Kokubun, Motohide; Nakazawa, Kazuhiro; Enoto, Teruaki; Fukazawa, Yasushi; Harayama, Atsushi; Hayashi, Katsuhiro; Kataoka, Jun; Katsuta, Junichiro; Kawaharada, Madoka; Laurent, Philippe; Lebrun, François; Limousin, Olivier; Makishima, Kazuo; Mizuno, Tsunefumi; Mori, Kunishiro; Nakamori, Takeshi; Noda, Hirofumi; Odaka, Hirokazu; Ohno, Masanori; Ohta, Masayuki; Saito, Shinya; Sato, Rie; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shinichiro; Terada, Yukikatsu; Uchiyama, Hideki; Uchiyama, Yasunobu; Watanabe, Shin; Yamaoka, Kazutaka; Yatsu, Yoichi; Yuasa, Takayuki

2014-07-01

The 6th Japanese X-ray satellite, ASTRO-H, is scheduled for launch in 2015. The hard X-ray focusing imaging system will observe astronomical objects with the sensitivity for detecting point sources with a brightness of 1/100,000 times fainter than the Crab nebula at > 10 keV. The Hard X-ray Imager (HXI) is a focal plane detector 12 m below the hard X-ray telescope (HXT) covering the energy range from 5 to 80 keV. The HXI is composed of a stacked Si/CdTe semiconductor detector module and surrounding BGO scintillators. The latter work as active shields for efficient reduction of background events caused by cosmic-ray particles, cosmic X-ray background, and in-orbit radiation activation. In this paper, we describe the detector system, and present current status of flight model development, and performance of HXI using an engineering model of HXI.

Broadband X-Ray Spectral Analysis of the Double-nucleus Luminous Infrared Galaxy Mrk 463

NASA Astrophysics Data System (ADS)

Yamada, Satoshi; Ueda, Yoshihiro; Oda, Saeko; Tanimoto, Atsushi; Imanishi, Masatoshi; Terashima, Yuichi; Ricci, Claudio

2018-05-01

We present a broadband (0.4–70 keV) X-ray spectral analysis of the luminous infrared galaxy (LIRG) system Mrk 463 observed with Nuclear Spectroscopic Telescope Array (NuSTAR), Chandra, and XMM-Newton, which contains double active galactic nuclei (AGNs; Mrk 463E and Mrk 463W) with a separation of ∼3.8 kpc. Detecting their transmitted hard X-ray >10 keV continua with NuSTAR, we confirm that Mrk 463E and Mrk 463W have AGNs with intrinsic luminosities of (1.6–2.2) × 1043 and (0.5–0.6) × 1043 erg s‑1 (2–10 keV) obscured by hydrogen column densities of 8 × 1023 and 3 × 1023 cm‑2, respectively. Both nuclei show strong reflection components from cold matter. The luminosity ratio between X-ray (2–10 keV) and [O IV] 25.89 μm of Mrk 463E is ∼5 times smaller than those of normal Seyfert galaxies, suggesting that the intrinsic SED is X-ray weak relative to the UV luminosity. In fact, the bolometric AGN luminosity of Mrk 463E estimated from L‧-band (3.8 μm), [O IV] 25.89 μm, and [Ne V] 14.32 μm lines indicate a large bolometric-to-X-ray luminosity ratio, κ 2–10 keV ≈ 110–410, and a high Eddington ratio, λ Edd ∼ 0.4–0.8. We suggest that the merger triggered a rapid growth of the black hole in Mrk 463E, which is not yet deeply “buried” by circumnuclear dust. By contrast, the L‧-band luminosity of Mrk 463W is unusually small relative to the X-ray luminosity, suggesting that the Eddington ratio is low (<10‑3) and it might be still in an early phase of merger-driven AGN activity.

Improving a high-efficiency, gated spectrometer for x-ray Thomson scattering experiments at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Döppner, T., E-mail: doeppner1@llnl.gov; Bachmann, B.; Emig, J.

We are developing x-ray Thomson scattering for applications in implosion experiments at the National Ignition Facility. In particular we have designed and fielded MACS, a high-efficiency, gated x-ray spectrometer at 7.5–10 keV [T. Döppner et al., Rev. Sci. Instrum. 85, 11D617 (2014)]. Here we report on two new Bragg crystals based on Highly Oriented Pyrolytic Graphite (HOPG), a flat crystal and a dual-section cylindrically curved crystal. We have performed in situ calibration measurements using a brass foil target, and we used the flat HOPG crystal to measure Mo K-shell emission at 18 keV in 2nd order diffraction. Such high photonmore » energy line emission will be required to penetrate and probe ultra-high-density plasmas or plasmas of mid-Z elements.« less

Improving a high-efficiency, gated spectrometer for x-ray Thomson scattering experiments at the National Ignition Facility

DOE PAGES

Döppner, T.; Kraus, D.; Neumayer, P.; ...

2016-08-03

We are developing x-ray Thomson scattering for applications in implosion experiments at the National Ignition Facility. In particular we have designed and fielded MACS, a high-efficiency, gated x-ray spectrometer at 7.5-10 keV [T. Döppner et al., Rev. Sci. Instrum. 85, 11D617 (2014)]. Here in this paper we report on two new Bragg crystals based on Highly Oriented Pyrolytic Graphite (HOPG), a flat crystal and a dual-section cylindrically curved crystal. We have performed in situ calibration measurements using a brass foil target, and we used the flat HOPG crystal to measure Mo K-shell emission at 18 keV in 2nd order diffraction.more » Such high photon energy line emission will be required to penetrate and probe ultra-high-density plasmas or plasmas of mid-Z elements.« less

The Structure of the Local Hot Bubble

NASA Technical Reports Server (NTRS)

Liu, W.; Chiao, M.; Collier, M. R.; Cravens, T.; Galeazzi, M.; Koutroumpa, D.; Kuntz, K. D.; Lallement, R.; Lepri, S. T.; McCammon, Dan;

Search for Hard X-Ray Emission from the Soft X-Ray Transient Aquila X-1

NASA Astrophysics Data System (ADS)

Harmon, B. A.; Zhang, S. N.; Paciesas, W. S.; Tavani, M.; Kaaret, P.; Ford, E.

1994-12-01

We are investigating the possibility of hard x-ray emission from the recurrent soft x-ray transient and x-ray burst source Aquila X-1 (Aql X-1). Outbursts of this source are relatively frequent with a spacing of ~ 4-10 months (Kitamoto, S. et al. 1993, ApJ, 403, 315). The recent detections of hard tails (\\(>\\)20 keV) in low luminosity x-ray bursters (Barret, D. & Vedrenne, G. 1994, ApJ Supp. S. 92, 505) suggest that neutron star transient systems such as Aql X-1 can produce hard x-ray emission which is detectable by BATSE. We are correlating reported optical and soft x-ray observations since 1991 of Aql X-1 with BATSE observations in order to search for hard x-ray emission episodes, and to study their temporal and spectral evolution. We will present preliminary results of this search in the 20-1000 keV band using the Earth occultation technique applied to the large area detectors. If this work is successful, we hope to alert the astronomical community for the next Aql X-1 outburst expected in 1995. Simultaneous x-ray/hard x-ray and optical observations of Aql X-1 during outburst would be of great importance for the modeling of soft x-ray transients and related systems.

Development of double-sided silicon strip detectors for solar hard x-ray observation

NASA Astrophysics Data System (ADS)

Saito, Shinya; Ishikawa, Shin-Nosuke; Watanabe, Shin; Odaka, Hirokazu; Sugimoto, Soichiro; Fukuyama, Taro; Kokubun, Motohide; Takahashi, Tadayuki; Terada, Yukikatsu; Tajima, Hiroyasu; Tanaka, Takaaki; Krucker, Säm; Christe, Steven; McBride, Steve; Glesener, Lindsay

2010-07-01

The Focusing Optics X-ray Solar Imager (FOXSI) is a rocket experiment scheduled for January 2011 launch. FOXSI observes 5 - 15 keV hard X-ray emission from quiet-region solar flares in order to study the acceleration process of electrons and the mechanism of coronal heating. For observing faint hard X-ray emission, FOXSI uses focusing optics for the first time in solar hard X-ray observation, and attains 100 times higher sensitivity than RHESSI, which is the present solar hard X-ray observing satellite. Now our group is working on developments of both Double-sided Silicon Strip Detector (DSSD) and read-out analog ASIC "VATA451" used for FOXSI. Our DSSD has a very fine strip pitch of 75 μm, which has sufficient position resolution for FOXSI mirrors with angular resolution (FWHM) of 12 arcseconds. DSSD also has high spectral resolution and efficiency in the FOXSI's energy range of 5 - 15 keV, when it is read out by our 64-channel analog ASIC. In advance of the FOXSI launch, we have established and tested a setup of 75 μm pitch DSSD bonded with "VATA451" ASICs. We successfully read out from almost all the channels of the detector, and proved ability to make a shadow image of tungsten plate. We also confirmed that our DSSD has energy resolution (FWHM) of 0.5 keV, lower threshold of 5 keV, and position resolution less than 63 μm. These performance satisfy FOXSI's requirements.

An Expanded Rossi X-Ray Timing Explorer Survey of X-Ray Variability in Seyfert 1 Galaxies

NASA Astrophysics Data System (ADS)

Markowitz, A.; Edelson, R.

2004-12-01

The first seven years of RXTE monitoring of Seyfert 1 active galactic nuclei have been systematically analyzed to yield five homogeneous samples of 2-12 keV light curves, probing hard X-ray variability on successively longer durations from ~1 day to ~3.5 yr. The 2-10 keV variability on timescales of ~1 day, as probed by ASCA, is included. All sources exhibit stronger X-ray variability toward longer timescales, but the increase is greater for relatively higher luminosity sources. Variability amplitudes are anticorrelated with X-ray luminosity and black hole mass, but amplitudes saturate and become independent of luminosity or black hole mass toward the longest timescales. The data are consistent with the models of power spectral density (PSD) movement described by Markowitz and coworkers and McHardy and coworkers, whereby Seyfert 1 galaxies' variability can be described by a single, universal PSD shape whose break frequency scales with black hole mass. The best-fitting scaling relations between variability timescale, black hole mass, and X-ray luminosity imply an average accretion rate of ~5% of the Eddington limit for the sample. Nearly all sources exhibit stronger variability in the relatively soft 2-4 keV band compared to the 7-12 keV band on all timescales. There are indications that relatively less luminous or less massive sources exhibit a greater degree of spectral variability for a given increase in overall flux.

Discovery of soft X-ray flux from 2A 1102+384 = Markarian 421

NASA Technical Reports Server (NTRS)

Hearn, D. R.; Marshall, F. J.; Jernigan, J. G.

1979-01-01

During April 1976 a soft X-ray flux was detected with SAS 3 from the vicinity of 2A 1102+384. The average flux densities were 4.3 x 10 to the -11th and 14 x 10 to the -11th erg/sq cm per sec in the energy bands 0.1-0.28 keV and 1-6 keV, respectively. There is an indication of variability over about 0.5 day in the lowest energy band. An upper limit of 3 x 10 to the 20th H atoms per sq cm is found for the gas column density to the X-ray source. In May 1978, observations with the modulation collimators of SAS 3 yielded an accurate (40 arcsec error radius) position for the X-ray source (2-6 keV) at right ascension 11 h 1 m 39.7 s, declination + 38 deg 28 min 51 sec (equinox 1950). The earlier tentative identification by Ricketts et al. (1976) with the BL Lacertae object B2 1101+38 = Markarian 421 is thus confirmed.

High-resolution hard x-ray spectroscopy of high-temperature plasmas using an array of quantum microcalorimeters.

PubMed

Thorn, Daniel B; Gu, Ming F; Brown, Greg V; Beiersdorfer, Peter; Porter, F Scott; Kilbourne, Caroline A; Kelley, Richard L

2008-10-01

Quantum microcalorimeters show promise in being able to fully resolve x-ray spectra from heavy highly charged ions, such as would be found in hot plasmas with temperatures in excess of 50 keV. Quantum microcalorimeter arrays are able to achieve this as they have a high-resolving power and good effective quantum efficiency for hard x-ray photons up to 60 keV. To demonstrate this, we present a measurement using an array of thin HgTe quantum microcalorimeters to measure the K-shell spectrum of hydrogenlike through carbonlike praseodymium (Z=57). With this device we are able to attain a resolving power, E/DeltaE, of 1000 at a photon energy of 37 keV.

Low energy X-ray spectra measured with a mercuric iodide energy dispersive spectrometer in a scanning electron microscope

NASA Technical Reports Server (NTRS)

Iwanczyk, J. S.; Dabrowski, A. J.; Huth, G. C.; Bradley, J. G.; Conley, J. M.

1986-01-01

A mercuric iodide energy dispersive X-ray spectrometer, with Peltier cooling provided for the detector and input field effect transistor, has been developed and tested in a scanning electron microscope. X-ray spectra were obtained with the 15 keV electron beam. An energy resolution of 225 eV (FWHM) for Mn-K(alpha) at 5.9 keV and 195 eV (FWHM) for the Mg-K line at 1.25 keV has been measured. Overall system noise level was 175 eV (FWHM). The detector system characterization with a carbon target demonstrated good energy sensitivity at low energies and lack of significant spectral artifacts at higher energies.

X-Ray Detector for 1 to 30 keV

NASA Technical Reports Server (NTRS)

Alcorn, G.; Jackson, J., Jr; Grant, P.; Marshall, F.

1983-01-01

Array of silicon X-ray detecting diodes measures photon energy and provides image of X-ray pattern. Regardless of thickness of new X-ray detector, depletion region extends through it. Impinging X-rays generate electrons in quantities proportional to X-ray energy. X-ray detector is mated to chargecoupled-device array for image generation and processing. Useful in industrial part inspection, pulsed-plasma research and medical application.

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

NASA Technical Reports Server (NTRS)

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.

Feasibility study of a ``4H'' X-ray camera based on GaAs:Cr sensor

NASA Astrophysics Data System (ADS)

Dragone, A.; Kenney, C.; Lozinskaya, A.; Tolbanov, O.; Tyazhev, A.; Zarubin, A.; Wang, Zhehui

2016-11-01

A multilayer stacked X-ray camera concept is described. This type of technology is called `4H' X-ray cameras, where 4H stands for high-Z (Z>30) sensor, high-resolution (less than 300 micron pixel pitch), high-speed (above 100 MHz), and high-energy (above 30 keV in photon energy). The components of the technology, similar to the popular two-dimensional (2D) hybrid pixelated array detectors, consists of GaAs:Cr sensors bonded to high-speed ASICs. 4H cameras based on GaAs also use integration mode of X-ray detection. The number of layers, on the order of ten, is smaller than an earlier configuration for single-photon-counting (SPC) mode of detection [1]. High-speed ASIC based on modification to the ePix family of ASIC is discussed. Applications in X-ray free electron lasers (XFELs), synchrotrons, medicine and non-destructive testing are possible.

A software platform for phase contrast x-ray breast imaging research.

PubMed

Bliznakova, K; Russo, P; Mettivier, G; Requardt, H; Popov, P; Bravin, A; Buliev, I

2015-06-01

To present and validate a computer-based simulation platform dedicated for phase contrast x-ray breast imaging research. The software platform, developed at the Technical University of Varna on the basis of a previously validated x-ray imaging software simulator, comprises modules for object creation and for x-ray image formation. These modules were updated to take into account the refractive index for phase contrast imaging as well as implementation of the Fresnel-Kirchhoff diffraction theory of the propagating x-ray waves. Projection images are generated in an in-line acquisition geometry. To test and validate the platform, several phantoms differing in their complexity were constructed and imaged at 25 keV and 60 keV at the beamline ID17 of the European Synchrotron Radiation Facility. The software platform was used to design computational phantoms that mimic those used in the experimental study and to generate x-ray images in absorption and phase contrast modes. The visual and quantitative results of the validation process showed an overall good correlation between simulated and experimental images and show the potential of this platform for research in phase contrast x-ray imaging of the breast. The application of the platform is demonstrated in a feasibility study for phase contrast images of complex inhomogeneous and anthropomorphic breast phantoms, compared to x-ray images generated in absorption mode. The improved visibility of mammographic structures suggests further investigation and optimisation of phase contrast x-ray breast imaging, especially when abnormalities are present. The software platform can be exploited also for educational purposes. Copyright © 2015 Elsevier Ltd. All rights reserved.

KINEMATICS OF SUPERBUBBLES AND SUPERSHELLS IN THE IRREGULAR GALAXY, NGC 1569

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sánchez-Cruces, M.; Rosado, M.; Rodríguez-González, A.

We present observations in the optical lines of Hα and [S II] (λλ6717, 6731 Å) and in X-rays of the irregular galaxy, NGC 1569. The observations in Hα and [S II] were made with the UNAM scanning Fabry-Perot interferometer (PUMA) and the X-ray data were obtained from the Chandra data archive. We detected several superbubbles, filaments, and supershells in NGC 1569 for which we determined size as well as their kinematic properties. We present a catalog of expansion velocities of 12 superbubbles, listing their positions, diameters, and physical parameters. Likewise, we present a catalog of 15 filaments and 4 supershells. In order tomore » identify possible X-ray emission from the superbubbles in this galaxy, we analyzed the X-ray emission of NGC 1569 in two energy bands: 0.2-2.0 keV (soft X-rays) and 2.0-8.0 keV (hard X-rays). Based on X-ray images, we detected X-ray emission that could possibly be related to some of the superbubbles. The spectrum of the X-ray superbubbles can be described by an optically thin thermal plasma model. In order to identify the possible coexistence of galactic super winds and superbubbles we have performed adiabatic three-dimensional N-body/smoothed particle hydrodynamics simulations to follow the evolution of the most important stellar clusters in this galaxy, SSC A and SSC B, using the GADGET-2 code. Those simulations demonstrate that depending on the specific initial conditions, the formation of superbubbles or a galactic superwind can result in NGC 1569.« less

X-rays and gamma-rays from accretion flows onto black holes in Seyferts and X-ray binaries

NASA Technical Reports Server (NTRS)

Zdziarski, Andrzej A.; Johnson, W. Neil; Poutanen, Juri; Magdziarz, Pawel; Gierlinski, Marek

1997-01-01

Observations and theoretical models of X-ray/gamma ray spectra of radio quiet Seyfert galaxies and Galactic black hole candidates are reviewed. The spectra from these objects share the following characteristics: an underlying power law with a high energy cutoff above 200 keV; a Compton reflection component with a Fe K alpha line, and a low energy absorption by intervening cold matter. The X-ray energy spectral index, alpha, is typically in the range between 0.8 and 1 in Seyfert spectra, and that of the hard state spectra of the black hole candidates Cygnus X-1 and GX 339-4 is typically between 0.6 and 0.8. The Compton reflection component corresponds with cold matter covering a solid angle of between 0.8pi and 2pi as seen from the X-ray source. The broadband spectra of both classes of sources are well fitted by Compton upscattering of soft photons in thermal plasma. The fits yield a thermal plasma temperature of 100 keV and the Thomson optical depth of 1. All the spectra presented are cut off before the electron rest energy 511 keV, indicating that electron/positron pair production is an important process.

On-ground calibration of the Hitomi Hard X-ray Telescopes

NASA Astrophysics Data System (ADS)

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

2018-01-01

We present x-ray characteristics of the Hard X-ray Telescopes (HXTs) on board the Hitomi (ASTRO-H) satellite. Measurements were conducted at the SPring-8 BL20B2 beamline and the ISAS/JAXA 27-m beamline. The angular resolution defined by a half-power diameter was 1.9‧ (HXT-1) and 2.1‧ (HXT-2) at 8 keV, 1.9‧ at 30 keV, and 1.8‧ at 50 keV. The effective area was found to be 620 cm2 at 8 keV, 178 cm2 at 30 keV, and 82 cm2 at 50 keV per mirror module. Although the angular resolutions were slightly worse than the requirement (1.7‧), the effective areas sufficiently exceeded the requirements of 150 cm2 at 30 keV and 55 cm2 at 50 keV. The off-axis measurements of the effective areas resulted in the field of view being 6.1‧ at 50 keV, 7.7‧ at 30 keV, and 9.7‧ at 8 keV in diameter. We confirmed that the main component of the stray x-ray light was significantly reduced by mounting the precollimator as designed. Detailed analysis of the data revealed that the angular resolution was degraded mainly by figure errors of mirror foils, and the angular resolution is completely explained by the figure errors, positioning errors of the foils, and conical approximation of the foil shape. We found that the effective areas were ˜80% of the designed values below 40 keV, whereas they steeply decline above 40 keV and become only ˜50%. We investigated this abrupt decline and found that neither the error of the multilayer design nor the errors of the incident angles induced by the positioning errors of the foils can be the cause. The reflection profile of each foil pair from the defocused image strongly suggests that the figure errors of the foils probably bring about the reduction in the effective areas at higher energies.

Suzaku Observation of Two Ultraluminous X-Ray Sources in NGC 1313

NASA Technical Reports Server (NTRS)

Mizuno, T.; Miyawaki, R.; Ebisawa, K.; Kubota, A.; Miyamoto, M.; Winter, L.; Ueda, Y.; Isobe, N.; Dewangan, G.; Done, C.;

Fundamental x-ray interaction limits in diagnostic imaging detectors: frequency-dependent Swank noise.

PubMed

Hajdok, G; Battista, J J; Cunningham, I A

2008-07-01

A frequency-dependent x-ray Swank factor based on the "x-ray interaction" modulation transfer function and normalized noise power spectrum is determined from a Monte Carlo analysis. This factor was calculated in four converter materials: amorphous silicon (a-Si), amorphous selenium (a-Se), cesium iodide (CsI), and lead iodide (PbI2) for incident photon energies between 10 and 150 keV and various converter thicknesses. When scaled by the quantum efficiency, the x-ray Swank factor describes the best possible detective quantum efficiency (DQE) a detector can have. As such, this x-ray interaction DQE provides a target performance benchmark. It is expressed as a function of (Fourier-based) spatial frequency and takes into consideration signal and noise correlations introduced by reabsorption of Compton scatter and photoelectric characteristic emissions. It is shown that the x-ray Swank factor is largely insensitive to converter thickness for quantum efficiency values greater than 0.5. Thus, while most of the tabulated values correspond to thick converters with a quantum efficiency of 0.99, they are appropriate to use for many detectors in current use. A simple expression for the x-ray interaction DQE of digital detectors (including noise aliasing) is derived in terms of the quantum efficiency, x-ray Swank factor, detector element size, and fill factor. Good agreement is shown with DQE curves published by other investigators for each converter material, and the conditions required to achieve this ideal performance are discussed. For high-resolution imaging applications, the x-ray Swank factor indicates: (i) a-Si should only be used at low-energy (e.g., mammography); (ii) a-Se has the most promise for any application below 100 keV; and (iii) while quantum efficiency may be increased at energies just above the K edge in CsI and PbI2, this benefit is offset by a substantial drop in the x-ray Swank factor, particularly at high spatial frequencies.

The gamma-ray emitting radio-loud narrow-line Seyfert 1 galaxy PKS 2004-447. I. The X-ray View

NASA Astrophysics Data System (ADS)

Kreikenbohm, A.; Schulz, R.; Kadler, M.; Wilms, J.; Markowitz, A.; Chang, C. S.; Carpenter, B.; Elsässer, D.; Gehrels, N.; Mannheim, K.; Müller, C.; Ojha, R.; Ros, E.; Trüstedt, J.

2016-01-01

As part of the TANAMI multiwavelength progam, we discuss new X-ray observations of the γ-ray and radio-loud narrow line Seyfert 1 galaxy (γ-NLS1) PKS 2004-447. The active galaxy is a member of a small sample of radio-loud NLS1s detected in γ-rays by the Fermi Large Area Telescope. It stands out for being the radio-loudest and the only southern-hemisphere source in this sample. We present results from our X-ray monitoring program comprised of Swift snapshot observations from 2012 through 2014 and two new X-ray observations with XMM-Newton in 2012. Supplemented by archival data from 2004 and 2011, our data set allows for a careful analysis of the X-ray spectrum and variability of this peculiar source. The (0.5-10) keV spectrum is described well by a power law (Γ ~ 1.6), which can be interpreted as non-thermal emission from a relativistic jet. The source exhibits moderate flux variability on timescales of both months and years. Correlated brightness variations in the (0.5-2) keV and (2-10) keV bands are explained by a single variable spectral component, such as the one from the jet. A possible soft excess seen in the data from 2004 cannot be confirmed by the new XMM-Newton observations taken during low-flux states. Any contribution to the total flux in 2004 is less than 20% of the power-law component. The (0.5-10) keV luminosities of PKS 2004-447 are in the range of (0.5-2.7) × 1044 erg s-1. A comparison of the X-ray properties among the known γ-NLS1 galaxies shows that in four out of five cases the X-ray spectrum is dominated by a flat power law without intrinsic absorption. These objects are moderately variable in their brightness, while spectral variability is observed in at least two sources. The major difference across the X-ray spectra of γ-NLS1s is the luminosity, which spans a range of almost two orders of magnitude from 1044 erg s-1 to 1046 erg s-1 in the (0.5-10) keV band.

Two new intermediate polars with a soft X-ray component

NASA Astrophysics Data System (ADS)

Anzolin, G.; de Martino, D.; Bonnet-Bidaud, J.-M.; Mouchet, M.; Gänsicke, B. T.; Matt, G.; Mukai, K.

2008-10-01

Aims: We analyze the first X-ray observations with XMM-Newton of 1RXS J070407.9+262501 and 1RXS 180340.0+401214, in order to characterize their broad-band temporal and spectral properties, also in the UV/optical domain, and to confirm them as intermediate polars. Methods: For both objects, we performed a timing analysis of the X-ray and UV/optical light curves to detect the white dwarf spin pulsations and study their energy dependence. For 1RXS 180340.0+401214 we also analyzed optical spectroscopic data to determine the orbital period. X-ray spectra were analyzed in the 0.2-10.0 keV range to characterize the emission properties of both sources. Results: We find that the X-ray light curves of both systems are energy dependent and are dominated, below 3-5 keV, by strong pulsations at the white dwarf rotational periods (480 s for 1RXS J070407.9+262501 and 1520.5 s for 1RXS 180340.0+401214). In 1RXS 180340.0+401214 we also detect an X-ray beat variability at 1697 s which, together with our new optical spectroscopy, favours an orbital period of 4.4 h that is longer than previously estimated. Both systems show complex spectra with a hard (temperature up to 40 keV) optically thin and a soft (kT ~ 85-100 eV) optically thick components heavily absorbed by material partially covering the X-ray sources. Conclusions: Our observations confirm the two systems as intermediate polars and also add them as new members of the growing group of “soft” systems which show the presence of a soft X-ray blackbody component. Differences in the temperatures of the blackbodies are qualitatively explained in terms of reprocessing over different sizes of the white dwarf spot. We suggest that systems showing cooler soft X-ray blackbody components also possess white dwarfs irradiated by cyclotron radiation. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA, and with the Observatoire de Haute Provence (CNRS), France.

Hard X-ray mirrors for Nuclear Security

DOE Office of Scientific and Technical Information (OSTI.GOV)

Descalle, M. A.; Brejnholt, N.; Hill, R.

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 newmore » 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, we conducted the first demonstration that reflective multilayer mirrors could be used as diagnostic for HED experiment with an order of magnitude improvement in signal-to-noise ratio for the multilayer optic compared a transmission crystal spectrometer.« less

Thermal and Nonthermal X-ray Emission from the Forward Shock in Tycho's Supernova Remnant

NASA Technical Reports Server (NTRS)

Hwang, Una; Decourchelle, Anne; Holt, Stephen S.; Petre, Robert; White, Nicholas E. (Technical Monitor)

2002-01-01

We present Chandra CCD images of Tycho's supernova remnant that delineate its outer shock, seen as a thin, smooth rim along the straight northeastern edge and most of the circular western half. The images also show that the Si and S ejecta are highly clumpy, and have reached the forward shock at numerous locations. Most of the X-ray spectra that we examine along the rim show line emission from Si and S, which in some cases must come from ejecta; the continuum is well represented by either thermal or nonthermal models. In the case that the continuum is assumed to be thermal, the temperatures at the rim are all similar at about 2 keV, and the ionization ages are very low because of the overall weakness of the line emission. Assuming shock velocities inferred from radio and X-ray expansion measurements, these temperatures are substantially below those expected for equilibration of the electron and ion temperatures; electron to mean temperature ratios of approximately less than 0.1 - 0.2 indicate at most modest collisionless heating of the electrons at the shock. The nonthermal contribution to these spectra may be important, however, and may account for as many as half of the counts in the 4-6 keV energy range, based on an extrapolation of the hard X-ray spectrum above 10 keV.

Observation of soft X-ray spectra from a Seyfert 1 and a narrow emission-line galaxy

NASA Technical Reports Server (NTRS)

Singh, K. P.; Garmire, G. P.; Nousek, J.

1985-01-01

The 0.2-40 keV X-ray spectra of the Seyfert 1 galaxy Mrk 509 and the narrow emission-line galaxy NGC 2992 are analyzed. The results suggest the presence of a steep soft X-ray component in Mrk 509 in addition to the well-known Gamma = 1.7 component found in other active galactic nuclei in the 2-40 keV energy range. The soft X-ray component is interpreted as due to thermal emission from a hot gas, probably associated with the highly ionized gas observed to be outflowing from the galaxy. The X-ray spectrum of NGC 2992 does not show any steepening in the soft X-ray band and is consistent with a single power law (Gamma = 1.78) with very low absorbing column density of 4 x 10 to the 21st/sq cm. A model with partial covering of the nuclear X-ray source is preferred, however, to a simple model with a single power law and absorption.

Fluorescent x-ray computed tomography to visualize specific material distribution

NASA Astrophysics Data System (ADS)

Takeda, Tohoru; Yuasa, Tetsuya; Hoshino, Atsunori; Akiba, Masahiro; Uchida, Akira; Kazama, Masahiro; Hyodo, Kazuyuki; Dilmanian, F. Avraham; Akatsuka, Takao; Itai, Yuji

1997-10-01

Fluorescent x-ray computed tomography (FXCT) is being developed to detect non-radioactive contrast materials in living specimens. The FXCT systems consists of a silicon channel cut monochromator, an x-ray slit and a collimator for detection, a scanning table for the target organ and an x-ray detector for fluorescent x-ray and transmission x-ray. To reduce Compton scattering overlapped on the K(alpha) line, incident monochromatic x-ray was set at 37 keV. At 37 keV Monte Carlo simulation showed almost complete separation between Compton scattering and the K(alpha) line. Actual experiments revealed small contamination of Compton scattering on the K(alpha) line. A clear FXCT image of a phantom was obtained. Using this system the minimal detectable dose of iodine was 30 ng in a volume of 1 mm3, and a linear relationship was demonstrated between photon counts of fluorescent x-rays and the concentration of iodine contrast material. The use of high incident x-ray energy allows an increase in the signal to noise ratio by reducing the Compton scattering on the K(alpha) line.

SphinX catalogue of small flares and brightenings

NASA Astrophysics Data System (ADS)

Gryciuk, Magdalena; Sylwester, Janusz; Gburek, Szymon; Siarkowski, Marek; Mrozek, Tomasz; Kepa, Anna

The Solar Photometer in X-rays (SphinX) was designed to measure soft X-ray solar emission in the energy range between 1 keV and 15 keV. The instrument operated from February until November 2009 aboard CORONAS-Photon satellite, during the phase of extraordinary low minimum of solar activity. Thanks to its very high sensitivity SphinX was able to record large number of tiny flares and brightenings. A catalogue of events observed by SphinX will be presented. Results of statistical analysis of events’ characteristics will be discussed.

UCSD OSO-7 observations of the hard X-ray spectrum and variability of Centaurus A

NASA Technical Reports Server (NTRS)

Mushotzky, R. F.; Baity, W. A.; Wheaton, W. A.; Peterson, L. E.

1976-01-01

Results are reported for four X-ray scans of the region containing Cen A. It is found that the X-ray source had a hard number spectrum (spectral index of -1.2) during these observations and that the intensity in the range from 10 to 100 keV apparently increased by 230% with no detectable change in spectral shape between two observations 210 days apart. Either a Compton-synchrotron mechanism or thermal bremsstrahlung at any temperature greater than 200 keV is suggested as the source of the X-rays. It is noted that the present observations, together with a similar detection of another galaxy, may establish a distinct class of extragalactic X-ray objects with flat and highly absorbed spectra.

Discovery of a Hand X-Ray Source, SAX J0635+0533, in the Error Box of the Gamma-Ray Source 2EG J0635+0521

NASA Technical Reports Server (NTRS)

Kaaret, P.; Piraino, S.; Halpern, Jules P.; Eracleous, M.; Oliversen, Ronald (Technical Monitor)

2001-01-01

We have discovered an X-ray source, SAX J0635+0533, with a hard spectrum within the error box of the GeV gamma-ray source in Monoceros, 2EG J0635+0521. The unabsorbed flux from the source is 1.2 x 10(exp -11) ergs /sq cm s in the 2-10 keV band. The X-ray spectrum is consistent with a simple power-law model with absorption. The photon index is 1.50 +/- 0.08, and we detect emission out to 40 keV. Optical observations identify a counterpart with a V magnitude of 12.8. The counterpart has broad emission lines and the colors of an early B-type star. If the identification of the X-ray/optical source with the gamma-ray source is correct, then the source would be a gamma-ray-emitting X-ray binary.

[Basic concepts of radiology physics].

PubMed

Gambini, D-J

2010-11-01

An x-ray tube mainly emits low-energy X-rays, with few maximum energy E₀ (equal in keV to the voltage U in kV) x-rays. Aluminium filtration (mandatory minimum thickness of 1.5 to 2.5 mm based on tube voltage) reduces soft X-rays and provides a mean energy equal to 2/3 E₀. The half value layer of a reference material characterizes the spectrum. X-ray attenuation in tissues is due to secondary electron interactions: photoelectric effect at low-energy, especially in dense materials with high Z number; compton effect at intermediate-energy, proportional to density. The optimization of acquisition parameters of a medically necessary examination is based on appropriate selection of the highest voltage (U in kV) providing the best contrast and lowest tube current (Q in mAs) providing a diagnostic image.

FOXSI: Properties of optics and detectors for hard-X rays

NASA Astrophysics Data System (ADS)

Buitrago-Casas, Juan Camilo; Glesener, Lindsay; Christe, Steven; Krucker, Sam; Ishikawa, Shin-nosuke; Foster, Natalie

2015-04-01

The Focusing Optics X-ray Solar Imager (FOXSI) is a state-of-the-art direct focusing X-ray telescope designed to observe the Sun. This experiment completed its second flight onboard a sounding rocket last December 11, 2014 from the White Sands Missile Range in New Mexico. The optics use a set of iridium-coated nickel/cobalt mirrors made using a replication technique based on an electroformed perfect polished surface. Since this technique creates full shells that no need to be co-aligned with other segments, an angular resolution of up to ~5 arcsec is gotten. The FOXSI focal plane consists of seven double-sided strip detectors. Five Silicon and 2 CdTe detectors were used during the second flight.We present on various properties of Wolter-I optics that are applicable to solar HXR observation, including ray-tracing simulations of the single-bounce (“ghost ray”) patterns from sources outside the field of view and angular resolution for different source angles and effective area measurements of the FOXSI optics. We also present the detectors calibration results, paying attention to energy resolution (~0.5 keV), energy thresholds (~4-15 keV for Silicon and ~4-20 keV for CdTe detectors), and spatial coherence of these values over the entire detector.

The Astro-H Soft X-Ray Mirror

NASA Technical Reports Server (NTRS)

Robinson, David; Okajima, Takashi; Serlemitsos, Peter; Soong, Yang

2012-01-01

The Astro-H is led by the Japanese Space Agency (JAXA) in collaboration with many other institutions including the NASA Goddard Space Flight Center. Goddard's contributions include two soft X-ray telescopes (SXTs). The telescopes have an effective area of 562 square cm at 1 keV and 425 square cm at 6 keV with an image quality requirement of 1.7 arc-minutes half power diameter (HPD). The engineering model has demonstrated 1.1 arc-minutes HPD error. The design of the SXT is based on the successful Suzaku mission mirrors with some enhancements to improve the image quality. Two major enhancements are bonding the X-ray mirror foils to alignment bars instead of allowing the mirrors to float, and fabricating alignment bars with grooves within 5 microns of accuracy. An engineering model SXT was recently built and subjected to several tests including vibration, thermal, and X-ray performance in a beamline. Several lessons were learned during this testing that will be incorporated in the flight design. Test results and optical performance are discussed, along with a description of the design of the SXT.

Imaging plates calibration to X-rays

NASA Astrophysics Data System (ADS)

Curcio, A.; Andreoli, P.; Cipriani, M.; Claps, G.; Consoli, F.; Cristofari, G.; De Angelis, R.; Giulietti, D.; Ingenito, F.; Pacella, D.

2016-05-01

The growing interest for the Imaging Plates, due to their high sensitivity range and versatility, has induced, in the last years, to detailed characterizations of their response function in different energy ranges and kind of radiation/particles. A calibration of the Imaging Plates BAS-MS, BAS-SR, BAS-TR has been performed at the ENEA-Frascati labs by exploiting the X-ray fluorescence of different targets (Ca, Cu, Pb, Mo, I, Ta) and the radioactivity of a BaCs source, in order to cover the X-ray range between few keV to 80 keV.

MAXI/GSC detection of a new outburst from SAX J1810.8-2609

NASA Astrophysics Data System (ADS)

Negoro, H.; Mihara, T.; Nakahira, S.; Yatabe, F.; Takao, Y.; Matsuoka, M.; Kawai, N.; Sugizaki, M.; Tachibana, Y.; Morita, K.; Sakamoto, T.; Serino, M.; Sugita, S.; Kawakubo, Y.; Hashimoto, T.; Yoshida, A.; Nakajima, M.; Sakamaki, A.; Maruyama, W.; Ueno, S.; Tomida, H.; Ishikawa, M.; Sugawara, Y.; Isobe, N.; Shimomukai, R.; Ueda, Y.; Tanimoto, A.; Morita, T.; Yamada, S.; Tsuboi, Y.; Iwakiri, W.; Sasaki, R.; Kawai, H.; Sato, T.; Tsunemi, H.; Yoneyama, T.; Yamauchi, M.; Hidaka, K.; Iwahori, S.; Kawamuro, T.; Yamaoka, K.; Shidatsu, M.

2018-05-01

We report a new X-ray outburst from the low-mass X-ray binary SAX J1810.8-2609 (aka V4722 Sgr; Ubertini et al. 1998, IAUC 6838) observed with MAXI/GSC. The enhancement was recognized from 2018 April 23 (MJD 58231), and X-ray count rates in the 2-4 keV and 4-10 keV bands peaked on April 26 at 0.085 +/- 0.008 c/s/cm2 ( 80 mCrab) and 0.096+/-0.008 c/s/cm2 ( 82 mCrab), respectively.

The high energy X-ray spectrum of 4U 0900-40 observed from OSO 8

NASA Technical Reports Server (NTRS)

Dolan, J. F.; Crannell, C. J.; Dennis, B. R.; Frost, K. J.; Orwig, L. E.; Ellison, D. C.

1981-01-01

The X-ray source 4U 0900-40 (= Vela XR-1) was observed with the high-energy X-ray spectrometer on OSO 8 for one week in 1976 and three weeks in 1978. Spectra of the source are presented above 16 keV. No systematic difference exists between the X-ray eclipse centers and the eclipse centers predicted from optical ephermerides. Short period intrinsic variability in the system's X-ray intensity may be related to changes in the Compton scattering optical depth in the system and does not require sporadic mass transfer via Roche lobe overflow. The 282 s modulation in the source's X-ray flux above 21 keV consists of two essentially similar pulses per period, most easily interpreted as arising from the two different magnetic poles of a rotating neutron star. The secondary appears to be a spherically accreting, magnetic neutron star.

Design and Development of Thin Plastic Foil, Conical Approximation, High Through-out X-Ray Telescope: Light Weight, Thin Plastic Foil, X-Ray Telescopes

NASA Technical Reports Server (NTRS)

Schnopper, Herbert W.; Barbera, Marco; Silver, Eric; Ingram, Russell; Christensen, Finn E.; Romaine, Suzanne; Cohen, Lester; Collura, Alfonso; Murray, Stephen S.; Brinton, John C. (Technical Monitor)

2002-01-01

We present results from a program to develop an X-ray telescope made from thin plastic shells. Our initial results have been obtained from multi-shell cylindrical lenses that are used in a point-to-point configuration to image the small focal spot of a an X-ray tube on a microchannel plate detector. We describe the steps that led up to the present design and present data from the tests that have been used to identify the properties of the plastic material that make it a suitable X-ray reflector. We discuss two applications of our technology to X-ray missions that are designed to address some of the scientific priorities set forth in NASA's long term plans for high energy astrophysics. One mission will observe in the 1 - 10 keV band, the other will extend up to ca. 100 keV.

A 7.2 keV spherical crystal backlighter system for Sandia's Z Pulsed Power Facility

NASA Astrophysics Data System (ADS)

Schollmeier, M.; Knapp, P. F.; Ampleford, D. J.; Loisel, G. P.; Robertson, G.; Shores, J. E.; Smith, I. C.; Speas, C. S.; Porter, J. L.; McBride, R. D.

2016-10-01

Many experiments on Sandia's Z facility, a 30 MA, 100 ns rise-time, pulsed-power driver, use a monochromatic Quartz crystal imaging backlighter system at 1.865 keV (Si Heα) or 6.151 keV (Mn Heα) x-ray energy to radiograph an imploding liner (cylindrical tube) or wire array. The x-ray source is generated by the Z-Beamlet Laser (ZBL), which provides up to 4.5 kJ at 527 nm during a 6 ns window. Radiographs of an imploding thick-walled Beryllium liner at a convergence ratio of about 20 [CR =Rin . (0) /Rin . (t) ] were too opaque to identify the inner surface of the liner with high confidence, demonstrating the need for a higher-energy x-ray backlighter between 6 and 10 keV. We present the design, test and first application of a Ge (335) spherical crystal x-ray backlighter system using the 7.242 keV Co Heα resonance line. The system operates at an almost identical Bragg angle as the existing 1.865 and 6.151 keV backlighters, enhancing our capabilities such as two-color, two-frame radiography, without changing detector shielding hardware. SAND No: SAND2016-6724 A. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. DoE NNSA under contract DE-AC04-94AL85000.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosch, R.; Boutin, J. Y.; Le Breton, J. P.

This article describes x-ray imaging with grazing-incidence microscopes, developed for the experimental program carried out on the Ligne d'Integration Laser (LIL) facility [J. P. Le Breton et al., Inertial Fusion Sciences and Applications 2001 (Elsevier, Paris, 2002), pp. 856-862] (24 kJ, UV--0.35 nm). The design includes a large target-to-microscope (400-700 mm) distance required by the x-ray ablation issues anticipated on the Laser MegaJoule facility [P. A. Holstein et al., Laser Part. Beams 17, 403 (1999)] (1.8 MJ) which is under construction. Two eight-image Kirkpatrick-Baez microscopes [P. Kirkpatrick and A. V. Baez J. Opt. Soc. Am. 38, 766 (1948)] with differentmore » spectral wavelength ranges and with a 400 mm source-to-mirror distance image the target on a custom-built framing camera (time resolution of {approx}80 ps). The soft x-ray version microscope is sensitive below 1 keV and its spatial resolution is better than 30 {mu}m over a 2-mm-diam region. The hard x-ray version microscope has a 10 {mu}m resolution over an 800-{mu}m-diam region and is sensitive in the 1-5 keV energy range. Two other x-ray microscopes based on an association of toroidal/spherical surfaces (T/S microscopes) produce an image on a streak camera with a spatial resolution better than 30 {mu}m over a 3 mm field of view in the direction of the camera slit. Both microscopes have been designed to have, respectively, a maximum sensitivity in the 0.1-1 and 1-5 keV energy range. We present the original design of these four microscopes and their test on a dc x-ray tube in the laboratory. The diagnostics were successfully used on LIL first experiments early in 2005. Results of soft x-ray imaging of a radiative jet during conical shaped laser interaction are shown.« less

Development of Si-APD Timing Detectors for Nuclear Resonant Scattering using High-energy Synchrotron X-rays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kishimoto, Shunji; Zhang Xiaowei; Yoda, Yoshitaka

2007-01-19

A timing detector with silicon avalanche photodiodes (Si-APDs) has been developed for nuclear resonant scattering using synchrotron x-rays. The detector had four pairs of a germanium plate 0.1mm thick and a Si-APD (3 mm in dia., a depletion layer of 30-{mu}m thickness). Using synchrotron x-rays of 67.4 keV, the efficiency increased to 1.5% for the incident beam, while the efficiency was 0.76 % without the germanium converters. A measurement of SR-PAC on Ni-61 was executed by using the detector. Some other types of timing detectors are planned for x-rays of E>20 keV.

Close-packed Arrays of Transition-edge X-ray Microcalorimeters with High Spectral Resolution at 5.9 keV

NASA Technical Reports Server (NTRS)

Iyomoto, N.; Bandler, S. R.; Brekosky, R. P.; Brown, A.-D.; Chervenak, J. A.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Porter, F. S.; Sadleir, J. E.;

Columbia University OSO-8 instrument for stellar and solar X-ray spectroscopy and polarimetry

NASA Technical Reports Server (NTRS)

Wolff, R. S.

1976-01-01

A spectrometer and a polarimeter consisting of large-area panels of mosaic crystals have been constructed and prepared for use in the OSO-8 satellite. The instrumentation is planned for study of stellar and solar X-ray spectra between 1.8-8 keV and stellar X-ray polarization at 2.6 keV. Aspects of the design which enable the instrument to make measurements of the diverse range of stellar and solar phenomena are described. Some of the unique features, such as high sensitivity, high temporal resolution, and spectral range, are discussed. The applicability of the spectrometer and polarimeter to various current problems in X-ray astronomy is considered.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Kyung -Wook; Karim, Karim S.

Direct conversion crystalline silicon X-ray imagers are used for low-energy X-ray photon (4-20 keV) detection in scientific research applications such as protein crystallography. In this paper, we demonstrate a novel pixel architecture that integrates a crystalline silicon X-ray detector with a thin-film transistor amorphous silicon pixel readout circuit. We describe a simplified two-mask process to fabricate a complete imaging array and present preliminary results that show the fabricated pixel to be sensitive to 5.89-keV photons from a low activity Fe-55 gamma source. Furthermore, this paper presented can expedite the development of high spatial resolution, low cost, direct conversion imagers formore » X-ray diffraction and crystallography applications.« less

X-Ray Spectra from MHD Simulations of Accreting Black Holes

NASA Technical Reports Server (NTRS)

Schnittman, Jeremy D.; Noble, Scott C.; Krolik, Julian H.

2011-01-01

We present new global calculations of X-ray spectra from fully relativistic magneto-hydrodynamic (MHO) simulations of black hole (BH) accretion disks. With a self consistent radiative transfer code including Compton scattering and returning radiation, we can reproduce the predominant spectral features seen in decades of X-ray observations of stellar-mass BHs: a broad thermal peak around 1 keV, power-law continuum up to >100 keV, and a relativistically broadened iron fluorescent line. By varying the mass accretion rate, different spectral states naturally emerge: thermal-dominant, steep power-law, and low/hard. In addition to the spectral features, we briefly discuss applications to X-ray timing and polarization.

Gamma-Ray Spectra & Variability of Cygnus X-1 Observed by BATSE

NASA Technical Reports Server (NTRS)

Ling, J. C.; Wheaton, A.; Wallyn, P.; Mahoney, W. A.; Paciesas, W. W.; Harmon, B. A.; Fishman, G. J.; Zhang, S. N.; Hua, X. M.

1996-01-01

We present new BATSE Earth occultation observations of the 25 keV-1.8 MeV spectrum and variability of Cygnus X-1 made between August 1993 and May 1994. We observed that the normal soft gamma-ray spectrum (gamma2) of Cygnus X-1 has two components: a Comptonized part seen below 30keV, and a high-energy tail in the 0.3-2 MeV range.

X-RAY FLARING ACTIVITY OF MRK 421 IN THE FIRST HALF OF 2013

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kapanadze, B.; Kapanadze, S.; Tabagari, L.

2016-11-01

We present the results of the Swift and NuSTAR observations of the nearby BL Lac object Mrk 421 during 2013 January–June. The source exhibited a strong long-term variability in the 0.3–10 keV and 3–79 keV bands with the maximum-to-minimum daily-binned flux ratios of 22 and 95, respectively, in about 3 months, mainly due to unprecedented strong X-ray outbursts by more than an order of magnitude in both bands within 2 weeks in 2013 April when the 0.3–10 keV count rate exceeded the level of 200 cts s{sup −1} for the first time, and Mrk 421 became one of the brightestmore » sources in the X-ray sky. The source was also very active on intra-day timescales, and it showed flux doubling and halving timescales of 1.16–7.20 hr and 1.04–3.54 hr, respectively. On some occasions, the flux varied by 4%–23% within 300–840 s. During this period, the source also exhibited some of the most extreme X-ray spectral variability ever reported for BL Lacs—the location of the synchrotron spectral energy distribution peak shifted from a few eV to ∼10 keV, and the photon index at 1 keV and curvature parameter varied on timescales from a few weeks down to intervals shorter than 1 ks. MAGIC and First G-APD Cherenkov Telescope observations also revealed a very strong very high energy (VHE) flare during April 11–17. The UV and HE γ -ray flares were much weaker compared to their X-ray counterparts, and they generally showed significantly stronger correlation with each other than with the X-ray fluxes.« less

High-spatial resolution and high-spectral resolution detector for use in the measurement of solar flare hard X-rays

NASA Technical Reports Server (NTRS)

Desai, U. D.; Orwig, Larry E.

1988-01-01

In the areas of high spatial resolution, the evaluation of a hard X-ray detector with 65 micron spatial resolution for operation in the energy range from 30 to 400 keV is proposed. The basic detector is a thick large-area scintillator faceplate, composed of a matrix of high-density scintillating glass fibers, attached to a proximity type image intensifier tube with a resistive-anode digital readout system. Such a detector, combined with a coded-aperture mask, would be ideal for use as a modest-sized hard X-ray imaging instrument up to X-ray energies as high as several hundred keV. As an integral part of this study it was also proposed that several techniques be critically evaluated for X-ray image coding which could be used with this detector. In the area of high spectral resolution, it is proposed to evaluate two different types of detectors for use as X-ray spectrometers for solar flares: planar silicon detectors and high-purity germanium detectors (HPGe). Instruments utilizing these high-spatial-resolution detectors for hard X-ray imaging measurements from 30 to 400 keV and high-spectral-resolution detectors for measurements over a similar energy range would be ideally suited for making crucial solar flare observations during the upcoming maximum in the solar cycle.

Multi-energy x-ray detector calibration for Te and impurity density (nZ) measurements of MCF plasmas

NASA Astrophysics Data System (ADS)

Maddox, J.; Pablant, N.; Efthimion, P.; Delgado-Aparicio, L.; Hill, K. W.; Bitter, M.; Reinke, M. L.; Rissi, M.; Donath, T.; Luethi, B.; Stratton, B.

2016-11-01

Soft x-ray detection with the new "multi-energy" PILATUS3 detector systems holds promise as a magnetically confined fusion (MCF) plasma diagnostic for ITER and beyond. The measured x-ray brightness can be used to determine impurity concentrations, electron temperatures, ne 2 Z eff products, and to probe the electron energy distribution. However, in order to be effective, these detectors which are really large arrays of detectors with photon energy gating capabilities must be precisely calibrated for each pixel. The energy-dependence of the detector response of the multi-energy PILATUS3 system with 100 K pixels has been measured at Dectris Laboratory. X-rays emitted from a tube under high voltage bombard various elements such that they emit x-ray lines from Zr-Lα to Ag-Kα between 1.8 and 22.16 keV. Each pixel on the PILATUS3 can be set to a minimum energy threshold in the range from 1.6 to 25 keV. This feature allows a single detector to be sensitive to a variety of x-ray energies, so that it is possible to sample the energy distribution of the x-ray continuum and line-emission. PILATUS3 can be configured for 1D or 2D imaging of MCF plasmas with typical spatial energy and temporal resolution of 1 cm, 0.6 keV, and 5 ms, respectively.

Plasma instability control toward high fluence, high energy x-ray continuum source

NASA Astrophysics Data System (ADS)

Poole, Patrick; Kirkwood, Robert; Wilks, Scott; Blue, Brent

2017-10-01

X-ray source development at Omega and NIF seeks to produce powerful radiation with high conversion efficiency for material effects studies in extreme fluence environments. While current K-shell emission sources can achieve tens of kJ on NIF up to 22 keV, the conversion efficiency drops rapidly for higher Z K-alpha energies. Pulsed power devices are efficient generators of MeV bremsstrahlung x-rays but are unable to produce lower energy photons in isolation, and so a capability gap exists for high fluence x-rays in the 30 - 100 keV range. A continuum source under development utilizes instabilities like Stimulated Raman Scattering (SRS) to generate plasma waves that accelerate electrons into high-Z converter walls. Optimizing instabilities using existing knowledge on their elimination will allow sufficiently hot and high yield electron distributions to create a superior bremsstrahlung x-ray source. An Omega experiment has been performed to investigate the optimization of SRS and high energy x-rays using Au hohlraums with parylene inner lining and foam fills, producing 10× greater x-ray yield at 50 keV than conventional direct drive experiments on the facility. Experiment and simulation details on this campaign will be presented. This work was performed under the auspices of the US DoE by LLNL under Contract No. DE-AC52-07NA27344.

Quantum efficiency measurements of eROSITA pnCCDs

NASA Astrophysics Data System (ADS)

Ebermayer, Stefanie; Andritschke, Robert; Elbs, Johannes; Meidinger, Norbert; Strüder, Lothar; Hartmann, Robert; Gottwald, Alexander; Krumrey, Michael; Scholze, Frank

2010-07-01

For the eROSITA X-ray telescope, which is planned to be launched in 2012, detectors were developed and fabricated at the MPI Semiconductor Laboratory. The fully depleted, back-illuminated pnCCDs have an ultrathin pn-junction to improve the low-energy X-ray response function and quantum efficiency. The device thickness of 450 μm is fully sensitive to X-ray photons yielding high quantum efficiency of more than 90% at photon energies of 10 keV. An on-chip filter is deposited on top of the entrance window to suppress visible and UV light which would interfere with the X-ray observations. The pnCCD type developed for the eROSITA telescope was characterized in terms of quantum efficiency and spectral response function. The described measurements were performed in 2009 at the synchrotron radiation sources BESSY II and MLS as cooperation between the MPI Semiconductor Laboratory and the Physikalisch-Technische Bundesanstalt (PTB). Quantum efficiency measurements over a wide range of photon energies from 3 eV to 11 keV as well as spectral response measurements are presented. For X-ray energies from 3 keV to 10 keV the quantum efficiency of the CCD including on-chip filter is shown to be above 90% with an attenuation of visible light of more than five orders of magnitude. A detector response model is described and compared to the measurements.

Simulation study of enhancing laser-driven multi-keV line-radiation through application of external magnetic fields

NASA Astrophysics Data System (ADS)

Kemp, G. Elijah; Colvin, J. D.; Fournier, K. B.; May, M. J.; Barrios, M. A.; Patel, M. V.; Koning, J. M.; Scott, H. A.; Marinak, M. M.

2015-11-01

Laser-driven, spectrally tailored, high-flux x-ray sources have been developed over the past decade for testing the radiation hardness of materials used in various civilian, space and military applications. The optimal electron temperatures for these x-ray sources occur around twice the desired photon energy. At the National Ignition Facility (NIF) laser, the available energy can produce plasmas with ~ 10keV electron temperatures which result in highly-efficient ~ 5keV radiation but less than optimal emission from the > 10keV sources. In this work, we present a possible venue for enhancing multi-keV x-ray emission on existing laser platforms through the application of an external magnetic field. Preliminary radiation-hydrodynamics calculations with Hydra suggest as much as 2 - 14 × increases in laser-to-x-ray conversion efficiency for 22 - 68keV K-shell sources are possible on the NIF laser - without any changes in laser-drive conditions - through the application of an external axial 50 T field. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.

A deep NuSTAR observation of M51: Investigating its Compton-thick nucleus, LINER companion and ULXs above 10 keV

NASA Astrophysics Data System (ADS)

Brightman, Murray; Annuar, Ady; Alexander, David M.; Earnshaw, Hannah; Gandhi, Poshak; Hornschemeier, Ann E.; Lehmer, Bret; Ptak, Andrew; Rangelov, Blagoy; Roberts, Tim P.; Stern, Daniel; Zezas, Andreas

2017-08-01

We present the results from a deep 200ks observation of M51 with NuSTAR. This observation was taken simultaneously with Chandra to provide soft-X-ray-coverage as well as to resolve the different point sources. We detect the Compton-thick nucleus of M51a, the LINER nucleus of M51b and several ultraluminous X-ray sources located in the galaxies above 10 keV. From X-ray torus modeling, we find that the covering factor of the torus in the nucleus of M51a is ~40% and supports a decline in the obscured fration at low X-ray luminosities. We find that the X-ray spectrum of the intermediate mass black hole candidate, ULX-7, is consistent with a power-law up to high energies, supporting its IMBH status. We further resolve the nucleus of M51b into two X-ray sources with Chandra, and measure its X-ray luminosity.

Soft X-ray spectral observations of quasars and high X-ray luminosity Seyfert galaxies

NASA Technical Reports Server (NTRS)

Petre, R.; Mushotzky, R. F.; Krolik, J. H.; Holt, S. S.

1983-01-01

Results of the analysis of 28 Einstein SSS observations of 15 high X-ray luminosity (L(x) 10 to the 435 power erg/s) quasars and Seyfert type 1 nuclei are presented. The 0.75-4.5 keV spectra are in general well fit by a simple model consisting of a power law plus absorption by cold gas. The averager spectral index alpha is 0.66 + or - .36, consistent with alpha for the spectrum of these objects above 2 keV. In all but one case, no evidence was found for intrinsic absorption, with an upper limit of 2 x 10 to the 21st power/sq cm. Neither was evidence found for partial covering of the active nucleus by dense, cold matter (N(H) 10 to the 22nd power/sq cm; the average upper limit on the partial covering fraction is 0.5. There is no obvious correlation between spectral index and 0175-4.5 keV X-ray luminosity (which ranges from 3 x 10 to the 43rd to 47th powers erg/s or with other source properties. The lack of intrinsic X-ray absorption allows us to place constraints on the density and temperature of the broad-line emission region, and narrow line emission region, and the intergalactic medium.

X-ray Binaries and the Galaxy Structure in Hard X-rays

NASA Astrophysics Data System (ADS)

Lutovinov, Alexander

The Galaxy structure in the hard X-ray energy band (¿20 keV) was studied using data of the INTEGRAL observatory. A deep and nearly uniform coverage of the galactic plane allowed to increase significantly the sensitivity of the survey and discover several dozens new galac-tic sources. The follow-up observations with XMM-Newton and CHANDRA observatories in X-rays and ground-based telescopes in optical and infrared wavebands gave us a possibility to determine optical counterparts and distances for number of new and already known faint sources. That, in turn, allowed us to build the spatial distribution of different classes of galactic X-ray binaries and obtain preliminary results of the structure of the further part of the Galaxy.

Hard x-ray broad band Laue lenses (80-600 keV): building methods and performances

NASA Astrophysics Data System (ADS)

Virgilli, E.; Frontera, F.; Rosati, P.; Liccardo, V.; Squerzanti, S.; Carassiti, V.; Caroli, E.; Auricchio, N.; Stephen, J. B.

2015-09-01

We present the status of the LAUE project devoted to develop a technology for building a 20 meter long focal length Laue lens for hard X-/soft gamma-ray astronomy (80-600 keV). The Laue lens is composed of bent crystals of Gallium Arsenide (GaAs, 220) and Germanium (Ge, 111), and, for the first time, the focusing property of bent crystals has been exploited for this field of applications. We show the preliminary results concerning the adhesive employed to fix the crystal tiles over the lens support, the positioning accuracy obtained and possible further improvements. The Laue lens petal that will be completed in a few months has a pass band of 80-300 keV and is a fraction of an entire Laue lens capable of focusing x-rays up to 600 keV, possibly extendable down to ~20-30 keV with suitable low absorption crystal materials and focal length. The final goal is to develop a focusing optics that can improve the sensitivity over current telescopes in this energy band by 2 orders of magnitude.

Increased x-ray conversion efficiency from ultra high contrast, relativistic laser pulse irradiation of large aspect ratio, vertically aligned nanowires

NASA Astrophysics Data System (ADS)

Hollinger, R. C.; Bargsten, C.; Shlyaptsev, V. N.; Kaymak, V.; Pukhov, A.; Capeluto, M. G.; Wang, Y.; Wang, S.; Rockwood, A.; Curtis, A.; Rocca, J. J.

2016-10-01

Recent experiments at Colorado State University have shown that the effective trapping of clean, Joule-level fs laser pulses of relativistic intensity in arrays of high aspect ratio aligned nanowire creates multi-kev, near solid density, large scale (>4um deep) plasmas. The drastically decreased radiative life time and increased hydrodynamic cooling time from these plasmas increases the x-ray conversion efficiency. We measured a record conversion efficiency of 10% into hv>1KeV photons (2pi steradians), and of 0.3% for hv>6KeV. The experiments used Au and Ni nanowires of 55nm, 80nm and 100nm in diameter with 12% of solid density irradiated by high contrast (>1012) pulses of 60fs FWHM duration from a frequency doubled Ti:Sa laser at intensities of I =5x1019Wcm-2. We also present preliminary results on x-ray emission from Rhodium nanowires in the 19-22KeV range and demonstrate the potential of this picosecond X-ray source in flash radiography. This work was supported by the Fusion Energy Program, Office of Science of the U.S Department of Energy, and by the Defense Threat Reduction Agency Grant HDTRA-1-10-1-0079.

Evaluation of a photon counting Medipix3RX CZT spectral x-ray detector

PubMed Central

Jorgensen, Steven M.; Vercnocke, Andrew J.; Rundle, David S.; Butler, Philip H.; McCollough, Cynthia H.; Ritman, Erik L.

2016-01-01

We assessed the performance of a cadmium zinc telluride (CZT)-based Medipix3RX x-ray detector as a candidate for micro-computed tomography (micro-CT) imaging. This technology was developed at CERN for the Large Hadron Collider. It features an array of 128 by 128, 110 micrometer square pixels, each with eight simultaneous threshold counters, five of which utilize real-time charge summing, significantly reducing the charge sharing between contiguous pixels. Pixel response curves were created by imaging a range of x-ray intensities by varying x-ray tube current and by varying the exposure time with fixed x-ray current. Photon energy-related assessments were made by flooding the detector with the tin foil filtered emission of an I-125 radioisotope brachytherapy seed and sweeping the energy threshold of each of the four charge-summed counters of each pixel in 1 keV steps. Long term stability assessments were made by repeating exposures over the course of one hour. The high properly-functioning pixel yield (99%), long term stability (linear regression of whole-chip response over one hour of acquisitions: y = −0.0038x + 2284; standard deviation: 3.7 counts) and energy resolution (2.5 keV FWHM (single pixel), 3.7 keV FWHM across the full image) make this device suitable for spectral micro-CT. The charge summing performance effectively reduced the measurement corruption caused by charge sharing which, when unaccounted for, shifts the photon energy assignment to lower energies, degrading both count and energy accuracy. Effective charge summing greatly improves the potential for calibrated, energy-specific material decomposition and K edge difference imaging approaches. PMID:27795606

Evaluation of a photon counting Medipix3RX CZT spectral x-ray detector.

PubMed

Jorgensen, Steven M; Vercnocke, Andrew J; Rundle, David S; Butler, Philip H; McCollough, Cynthia H; Ritman, Erik L

2016-08-28

We assessed the performance of a cadmium zinc telluride (CZT)-based Medipix3RX x-ray detector as a candidate for micro-computed tomography (micro-CT) imaging. This technology was developed at CERN for the Large Hadron Collider. It features an array of 128 by 128, 110 micrometer square pixels, each with eight simultaneous threshold counters, five of which utilize real-time charge summing, significantly reducing the charge sharing between contiguous pixels. Pixel response curves were created by imaging a range of x-ray intensities by varying x-ray tube current and by varying the exposure time with fixed x-ray current. Photon energy-related assessments were made by flooding the detector with the tin foil filtered emission of an I-125 radioisotope brachytherapy seed and sweeping the energy threshold of each of the four charge-summed counters of each pixel in 1 keV steps. Long term stability assessments were made by repeating exposures over the course of one hour. The high properly-functioning pixel yield (99%), long term stability (linear regression of whole-chip response over one hour of acquisitions: y = -0.0038x + 2284; standard deviation: 3.7 counts) and energy resolution (2.5 keV FWHM (single pixel), 3.7 keV FWHM across the full image) make this device suitable for spectral micro-CT. The charge summing performance effectively reduced the measurement corruption caused by charge sharing which, when unaccounted for, shifts the photon energy assignment to lower energies, degrading both count and energy accuracy. Effective charge summing greatly improves the potential for calibrated, energy-specific material decomposition and K edge difference imaging approaches.

Calibration of X-ray spectrometers for opacity experiments at the Orion laser facility (invited).

PubMed

Bentley, C; Allan, P; Brent, K; Bruce, N; Hoarty, D; Meadowcroft, A; Percival, J; Opie, C

2016-11-01

Accurately calibrated and characterised x-ray diagnostics are a key requirement in the fielding of experiments on the Orion laser where absolute measurements of x-ray emission are used to underpin the validity of models of emissivity and opacity. Diffraction crystals are used in spectrometers on Orion to record the dispersed spectral features emitted by the laser produced plasma to obtain a measurement of the plasma conditions. The ability to undertake diffraction crystal calibrations supports the successful outcome of these Orion experiments. This paper details the design and commissioning of a system to undertake these calibrations in the energy range 2.0 keV to approximately 8.5 keV. Improvements to the design are detailed which will extend the commissioned range of energies to below 1 keV.

A 70 Kiloparsec X-Ray Tail in the Cluster A3627

NASA Technical Reports Server (NTRS)

Sun, M.; Jones, C.; Forman, W.; Nulsen, P. E. J.; Donahue, M.; Voit, G. M.

2006-01-01

We present the discovery of a 70 kpc X-ray tail behind the small late-type galaxy ESO 137-001, in the nearby, hot (T=6.5 keV) merging cluster A3627, from both Chandra and XMM-Newton observations. The tail has a length-to-width ratio of approx. 10. It is luminous (L(0.5-2keV) approx 1041 ergs/s), with a temperature of approx. 0.7 keV and an X-ray gas mass of approx 10(exp 9) solar masses (approx 10% of the galaxy's stellar mass). We interpret this tail as the stripped interstellar medium of ESO 137-001 mixed with the hot cluster medium, with this blue galaxy being converted into a gas-poor galaxy. Three X-ray point sources are detected in the axis of the tail, which may imply active star formation there. The straightness and narrowness of the tail also imply that the turbulence in the intracluster medium is not strong on scales of 20-70 kpc.

X-ray observations of the colliding wind binary WR 25

NASA Astrophysics Data System (ADS)

Arora, Bharti; Pandey, Jeewan Chandra

2018-04-01

Using the archival data obtained from Chandra and Suzaku spanning over '8 years, we present an analysis of a WN6h+O4f Wolf-Rayet binary, WR 25. The X-ray light curves folded over a period of '208 d in the 0.3 - 10.0 keV energy band showed phase-locked variability where the count rates were found to be maximum near the periastron passage. The X-ray spectra of WR 25 were well explained by a two-temperature plasma model with temperatures of 0.64 ± 0.01 and 2.96 ± 0.05 keV and are consistent with previous results. The orbital phase dependent local hydrogen column density was found to be maximum just after the periastron passage, when the WN type star is in front of the O star. The hard (2.0 - 10.0 keV) X-ray luminosity was linearly dependent on the inverse of binary separation which confirms that WR 25 is a colliding wind binary.

A study of starting time in great hard X-ray flares

NASA Technical Reports Server (NTRS)

Klein, K. L.; Pick, M.; Magun, A.

1986-01-01

An analysis of the starting time in ten great hard X-ray bursts observed with the X-Ray Burst Spectrometer (HXRBS) is presented. It is shown that the impulsive phase of nine of them is composed of a preflash phase, during which the burst is observed up to an energy limit ranging from some tens of keV to 200 keV, followed ten to some tens of seconds afterwards by a flash phase, where the count rate rises simultaneously in all detector channels. For two events strong gamma-ray line emission is observed and is shown to start close to the onset of the flash phase.

X-ray Emission From Eta Carinae near Periastron in 2009 I: A Two State Solution

NASA Technical Reports Server (NTRS)

Hamaguchi, Kenji; Corcoran, Michael F.; Russell, Christopher; Pollock, Andrew M. T.; Gull, Theodore R.; Teodoro, Mairan; Madura, Thomas I.; Damineli, Augusto; Pittard, Julian M.

2014-01-01

X-ray emission from the supermassive binary system Eta Carinae declines sharply around periastron. This X-ray minimum has two distinct phases the lowest flux phase in the first 3 weeks and a brighter phase thereafter. In 2009, the Chandra X-ray Observatory monitored the first phase five times and found the lowest observed flux at 1.91012 ergs/sq cm/s (38 keV). The spectral shape changed such that the hard band above 4 keV dropped quickly at the beginning and the soft band flux gradually decreased to its lowest observed value in 2 weeks. The hard band spectrum had begun to recover by that time. This spectral variation suggests that the shocked gas producing the hottest X-ray gas near the apex of the wind-wind collision (WWC) is blocked behind the dense inner wind of the primary star, which later occults slightly cooler gas down-stream. Shocked gas previously produced by the system at earlier orbital phases is suggested to produce the faint residual X-ray emission seen when the emission near the apex is completely blocked by the primary wind. The brighter phase is probably caused by the re-appearance of the WWC plasma, whose emissivity significantly declined during the occultation. We interpret this to mean that the X-ray minimum is produced by a hybrid mechanism of an occultation and a decline in emissivity of the WWC shock. We constrain timings of superior conjunction and periastron based on these results.

X-Ray-induced Deuterium Enrichment of N-rich Organics in Protoplanetary Disks: An Experimental Investigation Using Synchrotron Light

NASA Astrophysics Data System (ADS)

Gavilan, Lisseth; Remusat, Laurent; Roskosz, Mathieu; Popescu, Horia; Jaouen, Nicolas; Sandt, Christophe; Jäger, Cornelia; Henning, Thomas; Simionovici, Alexandre; Lemaire, Jean Louis; Mangin, Denis; Carrasco, Nathalie

2017-05-01

The deuterium enrichment of organics in the interstellar medium, protoplanetary disks, and meteorites has been proposed to be the result of ionizing radiation. The goal of this study is to simulate and quantify the effects of soft X-rays (0.1-2 keV), an important component of stellar radiation fields illuminating protoplanetary disks, on the refractory organics present in the disks. We prepared tholins, nitrogen-rich organic analogs to solids found in several astrophysical environments, e.g., Titan’s atmosphere, cometary surfaces, and protoplanetary disks, via plasma deposition. Controlled irradiation experiments with soft X-rays at 0.5 and 1.3 keV were performed at the SEXTANTS beamline of the SOLEIL synchrotron, and were immediately followed by ex-situ infrared, Raman, and isotopic diagnostics. Infrared spectroscopy revealed the preferential loss of singly bonded groups (N-H, C-H, and R-N≡C) and the formation of sp3 carbon defects with signatures at ˜1250-1300 cm-1. Raman analysis revealed that, while the length of polyaromatic units is only slightly modified, the introduction of defects leads to structural amorphization. Finally, tholins were measured via secondary ion mass spectrometry to quantify the D, H, and C elemental abundances in the irradiated versus non-irradiated areas. Isotopic analysis revealed that significant D-enrichment is induced by X-ray irradiation. Our results are compared to previous experimental studies involving the thermal degradation and electron irradiation of organics. The penetration depth of soft X-rays in μm-sized tholins leads to volume rather than surface modifications: lower-energy X-rays (0.5 keV) induce a larger D-enrichment than 1.3 keV X-rays, reaching a plateau for doses larger than 5 × 1027 eV cm-3. Synchrotron fluences fall within the expected soft X-ray fluences in protoplanetary disks, and thus provide evidence of a new non-thermal pathway to deuterium fractionation of organic matter.

Simulation study of 3-5 keV x-ray conversion efficiency from Ar K-shell vs. Ag L-shell targets on the National Ignition Facility laser

NASA Astrophysics Data System (ADS)

Kemp, G. E.; Colvin, J. D.; Fournier, K. B.; May, M. J.; Barrios, M. A.; Patel, M. V.; Scott, H. A.; Marinak, M. M.

2015-05-01

Tailored, high-flux, multi-keV x-ray sources are desirable for studying x-ray interactions with matter for various civilian, space and military applications. For this study, we focus on designing an efficient laser-driven non-local thermodynamic equilibrium 3-5 keV x-ray source from photon-energy-matched Ar K-shell and Ag L-shell targets at sub-critical densities (˜nc/10) to ensure supersonic, volumetric laser heating with minimal losses to kinetic energy, thermal x rays and laser-plasma instabilities. Using Hydra, a multi-dimensional, arbitrary Lagrangian-Eulerian, radiation-hydrodynamics code, we performed a parameter study by varying initial target density and laser parameters for each material using conditions readily achievable on the National Ignition Facility (NIF) laser. We employ a model, benchmarked against Kr data collected on the NIF, that uses flux-limited Lee-More thermal conductivity and multi-group implicit Monte-Carlo photonics with non-local thermodynamic equilibrium, detailed super-configuration accounting opacities from Cretin, an atomic-kinetics code. While the highest power laser configurations produced the largest x-ray yields, we report that the peak simulated laser to 3-5 keV x-ray conversion efficiencies of 17.7% and 36.4% for Ar and Ag, respectively, occurred at lower powers between ˜100-150 TW. For identical initial target densities and laser illumination, the Ag L-shell is observed to have ≳10× higher emissivity per ion per deposited laser energy than the Ar K-shell. Although such low-density Ag targets have not yet been demonstrated, simulations of targets fabricated using atomic layer deposition of Ag on silica aerogels (˜20% by atomic fraction) suggest similar performance to atomically pure metal foams and that either fabrication technique may be worth pursuing for an efficient 3-5 keV x-ray source on NIF.

TES-Based X-Ray Microcalorimeter Performances Under AC Bias and FDM for Athena

NASA Technical Reports Server (NTRS)

Akamatsu, H.; Gottardi, L.; de Vries, C. P.; Adams, J. S.; Bandler, S. R.; Bruijn, M. P.; Chervenak, J. A.; Eckart, M. E.; Finkbeiner, F. M.; Gao, J. R.;

950 keV X-Band Linac For Material Recognition Using Two-Fold Scintillator Detector As A Concept Of Dual-Energy X-Ray System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Kiwoo; Natsui, Takuya; Hirai, Shunsuke

2011-06-01

One of the advantages of applying X-band linear accelerator (Linac) is the compact size of the whole system. That shows us the possibility of on-site system such as the custom inspection system in an airport. As X-ray source, we have developed X-band Linac and achieved maximum X-ray energy 950 keV using the low power magnetron (250 kW) in 2 {mu}s pulse length. The whole size of the Linac system is 1x1x1 m{sup 3}. That is realized by introducing X-band system. In addition, we have designed two-fold scintillator detector in dual energy X-ray concept. Monte carlo N-particle transport (MCNP) code wasmore » used to make up sensor part of the design with two scintillators, CsI and CdWO4. The custom inspection system is composed of two equipments: 950 keV X-band Linac and two-fold scintillator and they are operated simulating real situation such as baggage check in an airport. We will show you the results of experiment which was performed with metal samples: iron and lead as targets in several conditions.« less

ROSAT and ASCA Observations of the Seyfert Galaxy 1H0419-577-577, Identified with LB 1727

NASA Technical Reports Server (NTRS)

Turner, T. J.; George, I. M.; Nandra, K.; Marshall, H. L.; Grupe, D.; Remillard, R.; Leighly, K.

1998-01-01

We discuss the properties of the Seyfert 1.5 galaxy LB 1727 based upon the analysis of two ASCA observations, a two-month Rosat monitoring campaign, and optical data. The target is identified with the HEAO-A1 source 1H0419-577, so it has been observed by ASCA and ROSAT in order to obtain better X-ray variability and spectra data. Only modest (20%) variability is observed within or between ASCA and BeppoSAX observations in the approximately 2 - 10 keV band. However, the soft X-ray flux increased by a factor of 3 over a period of 2 months, while it was monitored daily by the ROSAT HRI instrument. The hard X-ray continuum can be parameterized as a power-law of slope Gamma approximately 1.5 - 1.6 across 0.7 - 11 keV in the rest-frame. We also report the first detection of an iron K(alpha) line in this source, consistent with emission from neutral material. The X-ray spectrum steepens sharply below 0.7 keV yielding a power-law of slope Gamma approximately 3.2. There is no evidence for absorption by neutral material, intrinsic to the nucleus. If the nucleus is unattenuated, then the break energy between the soft-excess and hard component is 0.7+/-0.08 keV. An ionized absorber may produce some turn-up in the spectrum at low energies, but a steepening of the underlying continuum is also required to explain the simultaneous ASCA and HRI data. We cannot rule out the possibility that a significant column of ionized material exists in the line-of-sight, if that is true, then the continuum break-energy can only be constrained to lie within the approximately 0.1 - 0.7 keV band.

ROSAT and ASCA Observations of the Seyfert Galaxy 1H0419-577, Identified with LB 1727

NASA Technical Reports Server (NTRS)

Turner, T. J.; George, I. M.; Nandra, K.; Grupe, D.; Remillard, R.; Leighly, K.; Marshall, H. L.

1998-01-01

We discuss the properties of the Seyfert 1.5 galaxy LB 1727 based upon the analysis of two ASCA observations, a two-month Rosat monitoring campaign, and optical data. The target is identified with the HEAO-A1 source 1H0419-577, so it has been observed by ASCA and ROSAT in order to obtain better X-ray variability and spectra data. Only modest (20%) variability is observed within or between ASCA and BeppoSAX observations in the approximately 2 - 10 keV band. However, the soft X-ray flux increased by a factor of 3 over a period of 2 months, while it was monitored daily by the ROSAT HRI instrument. The hard X-ray continuum can be parameterized as a power-law of slope Gamma approximately 1.5 - 1.6 across 9.7 - 11 keV in the rest-frame. We also report the first detection of an iron K(alpha) line in this source, consistent with emission from neutral material. The X-ray spectrum steepens sharply below 0.7 keV yielding a power-law of slope Gamma approximately 3.2. There is no evidence for absorption by neutral material, instrinsic to the nucleus. If the nucleus is unattenuated, then the break energy between the soft-excess and hard component is 0.7+/-0.08 keV. An ionized absorber may produce some tum-up in the spectrum at low energies, but a steepening of the underlying continuum is also required to explain the simultaneous ASCA and HRI data. We cannot rule out the possibility that a significant column of ionized material exists in the line-of-sight, if that is true, then the continuum break-energy can only be constrained to lie within the approximately 0.1 - -0.7 keV band.

Dynamics of the Upper Atmosphere X-ray Emission during the 23rd Solar Cycle

NASA Astrophysics Data System (ADS)

Pugacheva, Galina; Gusev, Anatoly; Martin, Inácio M.; Spjeldvik, Walther

Long-term observations with the RPS-1instrument on the CORONAS-F satellite (July 2001 to December 2005) permitted the evaluation of the low energy 3.0-31.5 keV X-ray emission flux radiated by the upper nocturnal atmosphere. This emission mostly results from the bremsstrahlung radiation from magnetospheric electrons. The entire nocturnal atmosphere emits energy in the range of 3 to 5 keV, especially in the southern hemisphere, over the Pacific and Indian ocean areas. In the northern hemisphere, the brightest emission from the atmo-sphere is observed at high latitudes in the region of Earth's radiation belt (ERB). In lower northern latitudes, the X-ray emission intensity is rather weak especially during the summer, and on 5-8 keV maps there are regions where there are no discernible emissions. At energies higher than 8 keV, only areas over the South-Atlantic magnetic anomaly and ERB at high latitudes are distinctly observed. This emission is produced by X-rays arising from interactions of ERB particles, descending to the altitude of 500 km in their bounce motion with the am-bient atmospheric matter, and by direct ERB particles passing through the lateral walls and entrance window of the detector (electrons with energies higher than 100 keV and protons with energies higher than 3 MeV). In order to determine the source mechanisms of soft X-rays in the energy range 3 to 8 keV from regions in the ERB, we studied the relationship between the seasonal variation of the X-ray atmospheric radiation and phases of the solar activity cycle. The global monthly, six-monthly, and yearly-averaged X-ray flux distributions were statistically determined for the five-year duration of the CORONAS-F mission. From these distributions, it is possible to infer about the influence of the phase of the solar activity and seasonal effects on the fluxes with energy in the range of 3 to 8 keV. Analysis of these data revealed important regularities in the behavior of this emission. We noted that the emission decreased about 10 times from 2001 to 2005, i.e. from maximum to almost minimum of the solar activity cycle 23 when mean annual values of sunspot number decreased from 110.6 to 28.9. Some compact terrestrial sources of unknown origin located outside of ERB zones were detected. Also, X-rays flux distributions out of ERB were obtained during five strong geomagnetic storms that oc-curred during the CORONAS-F mission on November 6 and 24, 2001; October 28 to November 4, 2003; November 20, 2004; and May15, 2005. (To the memory of V.M. Pankov and V.L. Prokhin, colleagues and coworkers in the Coronas-F mission.)

Solar flare hard and soft x ray relationship determined from SMM HXRBS and BCS data

NASA Technical Reports Server (NTRS)

Toot, G. David

1989-01-01

The exact nature of the solar flare process is still somewhat a mystery. A key element to understanding flares if the relationship between the hard x rays emitted by the most energetic portions of the flare and the soft x rays from other areas and times. This relationship was studied by comparing hard x ray light curved from the Hard X-Ray Burst Spectrometer (HXRBS) with the soft x ray light curve and its derivation from the Bent Crystal Spectrometer (BCS) which is part of the X-Ray Polychrometer (XRP), these instruments being on the Solar Maximum Mission spacecraft (SMM). Data sample was taken from flares observed with the above instruments during 1980, the peak of the previous maximum of solar activity. Flares were chosen based on complete coverage of the event by several instruments. The HXRBS data covers the x ray spectrum from about 25 keV to about 440 keV in 15 spectral channels, while the BCS data used covers a region of the Spectrum around 3 angstroms including emission from the Ca XIX ion. Both sets of data were summed over their spectral ranges and plotted against time at a maximum time resolution of around 3 seconds. The most popular theory of flares holds that a beam of electrons produces the hard x rays by bremsstrahlung while the soft x rays are the thermal response to this energy deposition. The question is whether the rate of change of soft x ray emission might reflect the variability of the electron beam and hence the variability of the hard x rays. To address this, we took the time derivative of the soft x ray light curve and compared it to the hard flares, 12 of them showed very closed agreement between the soft x ray derivative and the hard x ray light curve. The other five did not show this behavior but were similar to each other in general soft x ray behavior. Efforts to determine basic differences between the two kinds of flares continue. In addition the behavior of soft x ray temperature of flares was examined.

Solar flare hard and soft X ray relationship determined from SMM HXRBS and BCS data

NASA Astrophysics Data System (ADS)

Toot, G. David

1989-09-01

The exact nature of the solar flare process is still somewhat a mystery. A key element to understanding flares if the relationship between the hard x rays emitted by the most energetic portions of the flare and the soft x rays from other areas and times. This relationship was studied by comparing hard x ray light curved from the Hard X-Ray Burst Spectrometer (HXRBS) with the soft x ray light curve and its derivation from the Bent Crystal Spectrometer (BCS) which is part of the X-Ray Polychrometer (XRP), these instruments being on the Solar Maximum Mission spacecraft (SMM). Data sample was taken from flares observed with the above instruments during 1980, the peak of the previous maximum of solar activity. Flares were chosen based on complete coverage of the event by several instruments. The HXRBS data covers the x ray spectrum from about 25 keV to about 440 keV in 15 spectral channels, while the BCS data used covers a region of the Spectrum around 3 angstroms including emission from the Ca XIX ion. Both sets of data were summed over their spectral ranges and plotted against time at a maximum time resolution of around 3 seconds. The most popular theory of flares holds that a beam of electrons produces the hard x rays by bremsstrahlung while the soft x rays are the thermal response to this energy deposition. The question is whether the rate of change of soft x ray emission might reflect the variability of the electron beam and hence the variability of the hard x rays. To address this, we took the time derivative of the soft x ray light curve and compared it to the hard flares, 12 of them showed very closed agreement between the soft x ray derivative and the hard x ray light curve. The other five did not show this behavior but were similar to each other in general soft x ray behavior. Efforts to determine basic differences between the two kinds of flares continue. In addition the behavior of soft x ray temperature of flares was examined.

Operation of the CESR-TA vertical beam size monitor at Eb = 4 GeV

NASA Astrophysics Data System (ADS)

Alexander, J. P.; Conolly, C.; Edwards, E.; Flanagan, J. W.; Fontes, E.; Heltsley, B. K.; Lyndaker, A.; Peterson, D. P.; Rider, N. T.; Rubin, D. L.; Seeley, R.; Shanks, J.

2015-10-01

We describe operation of the CESR-TA vertical beam size monitor (xBSM) with e± beams with Eb=4 GeV. The xBSM measures vertical beam size by imaging synchrotron radiation x-rays through an optical element onto a detector array of 32 InGaAs photodiodes with 50 μm pitch. The device has previously been successfully used to measure vertical beam sizes of 10-100 μm on a bunch-by-bunch, turn-by-turn basis at e± beam energies of ~2 GeV and source magnetic fields below 2.8 kG, for which the detector required calibration for incident x-rays of 1-5 keV. At Eb = 4.0 GeV and B=4.5 kG, however, the incident synchrotron radiation spectrum extends to ~20 keV, requiring calibration of detector response in that regime. Such a calibration is described and then used to analyze data taken with several different thicknesses of filters in front of the detector. We obtain a relative precision of better than 4% on beam size measurement from 15 to 100 μm over several different ranges of x-ray energy, including both 1-12 keV and 6-17 keV. The response of an identical detector, but tilted vertically by 60° in order to increase magnification without a longer beamline, is measured and shown to improve x-ray detection above 4 keV without compromising sensitivity to beam size. We also investigate operation of a coded aperture using gold masking backed by synthetic diamond.

INVERSE COMPTON X-RAY EMISSION FROM TeV BLAZAR MRK 421 DURING A HISTORICAL LOW-FLUX STATE OBSERVED WITH NuSTAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kataoka, Jun; Stawarz, Łukasz, E-mail: kataoka.jun@waseda.jp

2016-08-10

We report on the detection of excess hard X-ray emission from the TeV BL Lac object Mrk 421 during the historical low-flux state of the source in 2013 January. Nuclear Spectroscopic Telescope Array observations were conducted four times between MJD 56294 and MJD 56312 with a total exposure of 80.9 ks. The source flux in the 3–40 keV range was nearly constant, except for MJD 56307 when the average flux level increased by a factor of three. Throughout the exposure, the X-ray spectra of Mrk 421 were well represented by a steep power-law model with a photon index of Γmore » ≃ 3.1, although a significant excess was noted above 20 keV in the MJD 56302 data when the source was in its faintest state. Moreover, Mrk 421 was detected at more than the 4 σ level in the 40–79 keV count maps for both MJD 56307 and MJD 56302 but not during the remaining two observations. The detected excess hard X-ray emission connects smoothly with the extrapolation of the high-energy γ -ray continuum of the blazar constrained by Fermi -LAT during source quiescence. These findings indicate that while the overall X-ray spectrum of Mrk 421 is dominated by the highest-energy tail of the synchrotron continuum, the variable excess hard X-ray emission above 20 keV (on the timescale of a week) is related to the inverse Compton emission component. We discuss the resulting constraints on the variability and spectral properties of the low-energy segment of the electron energy distribution in the source.« less

Development and tests of x-ray multifoil optical system for 1D imaging (Conference Presentation)

NASA Astrophysics Data System (ADS)

Pína, Ladislav; Hudec, René; Inneman, Adolf J.; Baca, Tomas; Blazek, M.; Platkevic, M.; Sieger, Ladislav; Doubravova, Daniela; McEntaffer, Randall L.; Schultz, Ted B.; Dániel, Vladimír.

2016-09-01

The proposed wide-field optical system has not been used yet. Described novel approach is based on the use of 1D "Lobster eye" optics in combination with Timepix X-ray detector in the energy range 3 - 40 keV. The proposed project includes theoretical study and a functional sample of the Timepix X-ray detector with multifoil wide-field X-ray "Lobster eye" optics. Using optics to focus X-rays on a detector is necessary in cases where the intensity of impinging X-ray radiation is below the sensitivity of the detector without optic. Generally this is the case of very low light phenomena, or e.g. monitoring astrophysical objects in space. Namely, such optical system could find applications in laboratory spectroscopy systems or in a rocket space experiment. Designed wide-field optical system combined with Timepix X-ray detector is described together with experimental results obtained during laboratory tests.

Generation of first hard X-ray pulse at Tsinghua Thomson Scattering X-ray Source.

PubMed

Du, Yingchao; Yan, Lixin; Hua, Jianfei; Du, Qiang; Zhang, Zhen; Li, Renkai; Qian, Houjun; Huang, Wenhui; Chen, Huaibi; Tang, Chuanxiang

2013-05-01

Tsinghua Thomson Scattering X-ray Source (TTX) is the first-of-its-kind dedicated hard X-ray source in China based on the Thomson scattering between a terawatt ultrashort laser and relativistic electron beams. In this paper, we report the experimental generation and characterization of the first hard X-ray pulses (51.7 keV) via head-on collision of an 800 nm laser and 46.7 MeV electron beams. The measured yield is 1.0 × 10(6) per pulse with an electron bunch charge of 200 pC and laser pulse energy of 300 mJ. The angular intensity distribution and energy spectra of the X-ray pulse are measured with an electron-multiplying charge-coupled device using a CsI scintillator and silicon attenuators. These measurements agree well with theoretical and simulation predictions. An imaging test using the X-ray pulse at the TTX is also presented.

The discovery of an 81 minute modulation of the X-ray flux from 2A0311-227

NASA Technical Reports Server (NTRS)

White, N. E.

1980-01-01

The X-ray flux from 2A0311-227 was modulated at the 81 min orbital period of its optical counterpart. An absorption dip with N sub H equivalent to 5 x 10 to the 22nd power H atoms per square cm was observed at magnetic phase 0.42. It was interpreted as the accretion column of a magnetic white dwarf passing in front of the X-ray source. The spectrum was thermal with a temperature of 18 keV and a 300 eV equivalent width iron line at 6.6 keV.

Simulation, optimization and testing of a novel high spatial resolution X-ray imager based on Zinc Oxide nanowires in Anodic Aluminium Oxide membrane using Geant4

NASA Astrophysics Data System (ADS)

Esfandi, F.; Saramad, S.

2015-07-01

In this work, a new generation of scintillator based X-ray imagers based on ZnO nanowires in Anodized Aluminum Oxide (AAO) nanoporous template is characterized. The optical response of ordered ZnO nanowire arrays in porous AAO template under low energy X-ray illumination is simulated by the Geant4 Monte Carlo code and compared with experimental results. The results show that for 10 keV X-ray photons, by considering the light guiding properties of zinc oxide inside the AAO template and suitable selection of detector thickness and pore diameter, the spatial resolution less than one micrometer and the detector detection efficiency of 66% are accessible. This novel nano scintillator detector can have many advantages for medical applications in the future.

Centaurus A /NGC 5128/ at 2 keV-2.3 MeV - HEAO 1 observations and implications

NASA Technical Reports Server (NTRS)

Baity, W. A.; Rothschild, R. E.; Lingenfelter, R. E.; Stein, W. A.; Nolan, P. L.; Gruber, D. E.; Knight, F. K.; Matteson, J. L.; Peterson, L. E.; Mushotzky, R. F.

1981-01-01

The active-nucleus galaxy Centaurus A has been studied at 2 keV-2.3 MeV using data from the UCSD/MIT hard X-ray and low-energy gamma-ray instrument and the GSFC/CIT cosmic X-ray experiment on HEAO-1. It is found that an E exp -1.60 + or - 0.03 power law spectrum breaking to E exp -2.0 + or - 0.2 at 140 keV best describes the January and July 1978 data. The average intensity was 50% higher during the January observations. Upper limits to unresolved lines at 511 keV and 1.6 MeV were found to be 6.5 x 10 to the -4th photons/sq cm-s and 2.2 x 10 to the -4th photons/sq cm-s, respectively, at the 90% confidence level. The present data are consistent with the detailed calculations of the synchrotron self-Compton mechanism; they may also agree, marginally, with the predictions of emission from spherical accretion onto black holes.

BioCARS: a synchrotron resource for time-resolved X-ray science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graber, T.; Anderson, S.; Brewer, H.

2011-08-16

BioCARS, a NIH-supported national user facility for macromolecular time-resolved X-ray crystallography at the Advanced Photon Source (APS), has recently completed commissioning of an upgraded undulator-based beamline optimized for single-shot laser-pump X-ray-probe measurements with time resolution as short as 100 ps. The source consists of two in-line undulators with periods of 23 and 27 mm that together provide high-flux pink-beam capability at 12 keV as well as first-harmonic coverage from 6.8 to 19 keV. A high-heat-load chopper reduces the average power load on downstream components, thereby preserving the surface figure of a Kirkpatrick-Baez mirror system capable of focusing the X-ray beammore » to a spot size of 90 {micro}m horizontal by 20 {micro}m vertical. A high-speed chopper isolates single X-ray pulses at 1 kHz in both hybrid and 24-bunch modes of the APS storage ring. In hybrid mode each isolated X-ray pulse delivers up to {approx}4 x 10{sup 10} photons to the sample, thereby achieving a time-averaged flux approaching that of fourth-generation X-FEL sources. A new high-power picosecond laser system delivers pulses tunable over the wavelength range 450-2000 nm. These pulses are synchronized to the storage-ring RF clock with long-term stability better than 10 ps RMS. Monochromatic experimental capability with Biosafety Level 3 certification has been retained.« less

Dose-response curve of EBT, EBT2, and EBT3 radiochromic films to synchrotron-produced monochromatic x-ray beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Thomas A. D.; Hogstrom, Kenneth R.; Alvarez, Diane

Purpose: This work investigates the dose-response curves of GAFCHROMIC{sup Registered-Sign} EBT, EBT2, and EBT3 radiochromic films using synchrotron-produced monochromatic x-ray beams. EBT2 film is being utilized for dose verification in photoactivated Auger electron therapy at the Louisiana State University Center for Advanced Microstructures and Devices (CAMD) synchrotron facility. Methods: Monochromatic beams of 25, 30, and 35 keV were generated on the tomography beamline at CAMD. Ion chamber depth-dose measurements were used to determine the dose delivered to films irradiated at depths from 0.7 to 8.5 cm in a 10 Multiplication-Sign 10 Multiplication-Sign 10-cm{sup 3} polymethylmethacrylate phantom. AAPM TG-61 protocol wasmore » applied to convert measured ionization into dose. Films were digitized using an Epson 1680 Professional flatbed scanner and analyzed using the net optical density (NOD) derived from the red channel. A dose-response curve was obtained at 35 keV for EBT film, and at 25, 30, and 35 keV for EBT2 and EBT3 films. Calibrations of films for 4 MV x-rays were obtained for comparison using a radiotherapy accelerator at Mary Bird Perkins Cancer Center. Results: The sensitivity (NOD per unit dose) of EBT film at 35 keV relative to that for 4-MV x-rays was 0.73 and 0.76 for doses 50 and 100 cGy, respectively. The sensitivity of EBT2 film at 25, 30, and 35 keV relative to that for 4-MV x-rays varied from 1.09-1.07, 1.23-1.17, and 1.27-1.19 for doses 50-200 cGy, respectively. For EBT3 film the relative sensitivity was within 3% of unity for all three monochromatic x-ray beams. Conclusions: EBT and EBT2 film sensitivity showed strong energy dependence over an energy range of 25 keV-4 MV, although this dependence becomes weaker for larger doses. EBT3 film shows weak energy dependence, indicating that it would be a better dosimeter for kV x-ray beams where beam hardening effects can result in large changes in the effective energy.« less

The X-ray emitting galaxy Cen-A

NASA Technical Reports Server (NTRS)

Mushotzky, R. F.; Sercemitsos, P. J.; Becker, R. H.; Boldt, E. A.; Holt, S. S.

1977-01-01

OSO-8 X-ray observations of Cen-A in 1975 and 1976 are reported. The source spectrum is well fit in both years by a power law of number index 1.62 and absorption due to 1.3 x 10 to the 23rd power at/sq cm. The total flux varied by a factor 2 between 1975 and 1976. In 1976 there were approximately 40% flux variations on a time scale of days. The 6.4 keV Fe fluorescent line and the 7.1 keV absorption edge were measured implying Fe/H approximately equals .000016. Simultaneous radio measurements show variation in phase with X-ray variability. Models considering radio, milimeter, IR and X-ray data show that all the data can be accounted for by a model in which the X-rays are due to a synchrotron self-Compton source embedded in a cold H(2) cloud.

Chandra Observation of Polaris: Census of Low-mass Companions

NASA Astrophysics Data System (ADS)

Evans, Nancy Remage; Guinan, Edward; Engle, Scott; Wolk, Scott J.; Schlegel, Eric; Mason, Brian D.; Karovska, Margarita; Spitzbart, Bradley

2010-05-01

We have observed Cepheid Polaris (α UMi A: F7 Ib [Aa] + F6 V [Ab]) with Chandra ACIS-I for 10 ks. An X-ray source was found at the location of Polaris with log LX = 28.89 erg s-1 (0.3-8 keV) and kT = 0.6 keV. A spectrum this soft could come from either the supergiant or the dwarf, as shown by comparable coronal stars. Two resolved low-mass visual companions, "C" and "D," are not physical members of the system based on the lack of X-rays (indicating an age older than the Cepheid) and inconsistent proper motions. Polaris B is not an X-ray source, consistent with its early F spectral type, and probably does not have a lower mass companion itself. A possible more distant member is identified, and an additional less plausible one. This provides a complete census of companions out to 0.1 pc covering a mass ratio range of an order of magnitude and a ΔV of nearly 15 mag. Based on observations made with the NASA Chandra Satellite.

Characterising the large coherence length at diamond’s beamline I13L

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagner, U. H., E-mail: ulrich.wagner@diamond.ac.uk; Parsons, A.; Rahomaki, J.

2016-07-27

I13 is a 250 m long hard x-ray beamline (6 keV to 35 keV) at the Diamond Light Source. The beamline comprises of two independent experimental endstations: one for imaging in direct space using x-ray microscopy and one for imaging in reciprocal space using coherent diffraction based imaging techniques [1]. An outstanding feature of the coherence branch, due to its length and a new generation of ultra-stable beamline instrumentation [2], is its capability of delivering a very large coherence length well beyond 200 μm, providing opportunities for unique x-ray optical experiments. In this paper we discuss the challenges of measuringmore » a large coherence length and present quantitative measurement based on analyzing diffraction patterns from a boron fiber [3]. We also discuss the limitations of this classical method in respect to detector performance, very short and long coherence lengths. Furthermore we demonstrate how a Ronchi grating setup [4] can be used to quickly establish if the beam is coherent over a large area.« less

IGR J17329-2731: The birth of a symbiotic X-ray binary

NASA Astrophysics Data System (ADS)

Bozzo, E.; Bahramian, A.; Ferrigno, C.; Sanna, A.; Strader, J.; Lewis, F.; Russell, D. M.; di Salvo, T.; Burderi, L.; Riggio, A.; Papitto, A.; Gandhi, P.; Romano, P.

2018-05-01

We report on the results of the multiwavelength campaign carried out after the discovery of the INTEGRAL transient IGR J17329-2731. The optical data collected with the SOAR telescope allowed us to identify the donor star in this system as a late M giant at a distance of 2.7-1.2+3.4 kpc. The data collected quasi-simultaneously with XMM-Newton and NuSTAR showed the presence of a modulation with a period of 6680 ± 3 s in the X-ray light curves of the source. This unveils that the compact object hosted in this system is a slowly rotating neutron star. The broadband X-ray spectrum showed the presence of a strong absorption (≫1023 cm-2) and prominent emission lines at 6.4 keV, and 7.1 keV. These features are usually found in wind-fed systems, in which the emission lines result from the fluorescence of the X-rays from the accreting compact object on the surrounding stellar wind. The presence of a strong absorption line around 21 keV in the spectrum suggests a cyclotron origin, thus allowing us to estimate the neutron star magnetic field as 2.4 × 1012 G. All evidencethus suggests IGR J17329-2731 is a symbiotic X-ray binary. As no X-ray emission was ever observed from the location of IGR J17329-2731 by INTEGRAL (or other X-ray facilities) during the past 15 yr in orbit and considering that symbiotic X-ray binaries are known to be variable but persistent X-ray sources, we concluded that INTEGRAL caught the first detectable X-ray emission from IGR J17329-2731 when the source shined as a symbiotic X-ray binary. The Swift XRT monitoring performed up to 3 months after the discovery of the source, showed that it maintained a relatively stable X-ray flux and spectral properties.

Spectral and timing properties of the accreting X-ray millisecond pulsar IGR J17498-2921

NASA Astrophysics Data System (ADS)

Falanga, M.; Kuiper, L.; Poutanen, J.; Galloway, D. K.; Bozzo, E.; Goldwurm, A.; Hermsen, W.; Stella, L.

2012-09-01

Context. IGR J17498-2921 is the third X-ray transient accreting millisecond pulsar discovered by INTEGRAL. It was in outburst for about 40 days beginning on August 08, 2011. Aims: We analyze the spectral and timing properties of the object and the characteristics of X-ray bursts to constrain the physical processes responsible for the X-ray production in this class of sources. Methods: We studied the broad-band spectrum of the persistent emission in the 0.6-300 keV energy band using simultaneous INTEGRAL, RXTE, and Swift data obtained in August-September 2011. We also describe the timing properties in the 2-100 keV energy range such as the outburst lightcurve, pulse profile, pulsed fraction, pulsed emission, time lags, and study the properties of X-ray bursts discovered by RXTE, Swift, and INTEGRAL and the recurrence time. Results: The broad-band average spectrum is well-described by thermal Comptonization with an electron temperature of kTe ~ 50 keV, soft seed photons of kTbb ~ 1 keV, and Thomson optical depth τT ~ 1 in a slab geometry. The slab area corresponds to a black body radius of Rbb ~ 9 km. During the outburst, the spectrum stays remarkably stable with plasma and soft seed photon temperatures and scattering optical depth that are constant within the errors. This behavior has been interpreted as indicating that the X-ray emission originates above the neutron star (NS) surface in a hot slab (either the heated NS surface or the accretion shock). The INTEGRAL, RXTE, and Swift data reveal the X-ray pulsation at a period of 2.5 ms up to ~65 keV. The pulsed fraction is consistent with being constant, i.e. energy independent and has a typical value of 6-7%. The nearly sinusoidal pulses show soft lags that seem to saturate near 10 keV at a rather small value of ~-60 μs with those observed in other accreting pulsars. The short burst profiles indicate that there is a hydrogen-poor material at ignition, which suggests either that the accreted material is hydrogen-deficient, or that the CNO metallicity is up to a factor of about two times solar. However, the variation in the burst recurrence time as a function of ṁ (inferred from the X-ray flux) is much smaller than predicted by helium-ignition models.

Calculation of x-ray spectra emerging from an x-ray tube. Part I. electron penetration characteristics in x-ray targets.

PubMed

Poludniowski, Gavin G; Evans, Philip M

2007-06-01

The penetration characteristics of electron beams into x-ray targets are investigated for incident electron kinetic energies in the range 50-150 keV. The frequency densities of electrons penetrating to a depth x in a target, with a fraction of initial kinetic energy, u, are calculated using Monte Carlo methods for beam energies of 50, 80, 100, 120 and 150 keV in a tungsten target. The frequency densities for 100 keV electrons in Al, Mo and Re targets are also calculated. A mixture of simple modeling with equations and interpolation from data is used to generalize the calculations in tungsten. Where possible, parameters derived from the Monte Carlo data are compared to experimental measurements. Previous electron transport approximations in the semiempirical models of other authors are discussed and related to this work. In particular, the crudity of the use of the Thomson-Whiddington law to describe electron penetration and energy loss is highlighted. The results presented here may be used towards calculating the target self-attenuation correction for bremsstrahlung photons emitted within a tungsten target.

All-Sky Monitoring with the Fermi Gamma Ray Burst Monitor

NASA Technical Reports Server (NTRS)

Wilson-Hodge, Colleen A.

2010-01-01

We are currently monitoring the transient hard X-ray/soft gamma ray sky using the Gamma Ray Burst Monitor (GBM) on-board Fermi. The twelve GBM NaI detectors span 8 keV to 1MeV, while the two GBM BGO detectors span about 150 keV to 40 MeV. With GBM, we detect transient events on multiple timescales. Brief events, such as Gamma Ray Bursts, Solar flares, and magnetar bursts are detected with on-board triggers. On longer timescales, we use the Earth occultation technique to monitor a number of sources, including X-ray binaries, AGN, and solar flaring activity. To date we have detected 7 sources above 100 keV. Transient activity from accretion-powered pulsars is monitored using epoch-folding techniques. With GBM we track the pulsed flux and frequency for a number of pulsars. We will present highlights of GBM observations on various timescales.

Development and verification of signal processing system of avalanche photo diode for the active shields onboard ASTRO-H

NASA Astrophysics Data System (ADS)

Ohno, M.; Kawano, T.; Edahiro, I.; Shirakawa, H.; Ohashi, N.; Okada, C.; Habata, S.; Katsuta, J.; Tanaka, Y.; Takahashi, H.; Mizuno, T.; Fukazawa, Y.; Murakami, H.; Kobayashi, S.; Miyake, K.; Ono, K.; Kato, Y.; Furuta, Y.; Murota, Y.; Okuda, K.; Wada, Y.; Nakazawa, K.; Mimura, T.; Kataoka, J.; Ichinohe, Y.; Uchida, Y.; Katsuragawa, M.; Yoneda, H.; Sato, G.; Sato, R.; Kawaharada, M.; Harayama, A.; Odaka, H.; Hayashi, K.; Ohta, M.; Watanabe, S.; Kokubun, M.; Takahashi, T.; Takeda, S.; Kinoshita, M.; Yamaoka, K.; Tajima, H.; Yatsu, Y.; Uchiyama, H.; Saito, S.; Yuasa, T.; Makishima, K.; ASTRO-H HXI/SGD Team

2016-09-01

The hard X-ray Imager and Soft Gamma-ray Detector onboard ASTRO-H demonstrate high sensitivity to hard X-ray (5-80 keV) and soft gamma-rays (60-600 keV), respectively. To reduce the background, both instruments are actively shielded by large, thick Bismuth Germanate scintillators. We have developed the signal processing system of the avalanche photodiode in the BGO active shields and have demonstrated its effectiveness after assembly in the flight model of the HXI/SGD sensor and after integration into the satellite. The energy threshold achieved is about 150 keV and anti-coincidence efficiency for cosmic-ray events is almost 100%. Installed in the BGO active shield, the developed signal processing system successfully reduces the room background level of the main detector.

Absolute brightness modeling for improved measurement of electron temperature from soft x-rays on MST

NASA Astrophysics Data System (ADS)

Reusch, L. M.; Franz, P.; Goetz, J. A.; den Hartog, D. J.; Nornberg, M. D.; van Meter, P.

2017-10-01

The two-color soft x-ray tomography (SXT) diagnostic on MST is now capable of Te measurement down to 500 eV. The previous lower limit was 1 keV, due to the presence of SXR emission lines from Al sputtered from the MST wall. The two-color technique uses two filters of different thickness to form a coarse spectrometer to estimate the slope of the continuum x-ray spectrum, which depends on Te. The 1.6 - 2.0 keV Al emission lines were previously filtered out by using thick Be filters (400 µm and 800 µm), thus restricting the range of the SXT diagnostic to Te >= 1 keV. Absolute brightness modeling explicitly includes several sources of radiation in the analysis model, enabling the use of thinner filters and measurement of much lower Te. Models based on the atomic database and analysis structure (ADAS) agree very well with our experimental SXR measurements. We used ADAS to assess the effect of bremsstrahlung, recombination, dielectronic recombination, and line emission on the inferred Te. This assessment informed the choice of the optimum filter pair to extend the Te range of the SXT diagnostic. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Fusion Energy Sciences program under Award Numbers DE-FC02-05ER54814 and DE-SC0015474.

X-RAY EMISSION FROM THE WOLF-RAYET BUBBLE S 308

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toala, J. A.; Guerrero, M. A.; Chu, Y.-H.

The Wolf-Rayet (WR) bubble S 308 around the WR star HD 50896 is one of the only two WR bubbles known to possess X-ray emission. We present XMM-Newton observations of three fields of this WR bubble that, in conjunction with an existing observation of its northwest quadrant, map most of the nebula. The X-ray emission from S 308 displays a limb-brightened morphology, with a central cavity {approx}22' in size and a shell thickness of {approx}8'. This X-ray shell is confined by the optical shell of ionized material. The spectrum is dominated by the He-like triplets of N VI at 0.43more » keV and O VII at 0.57 keV, and declines toward high energies, with a faint tail up to 1 keV. This spectrum can be described by a two-temperature optically thin plasma emission model (T{sub 1} {approx} 1.1 Multiplication-Sign 10{sup 6} K, T{sub 2} {approx} 13 Multiplication-Sign 10{sup 6} K), with a total X-ray luminosity {approx}2 Multiplication-Sign 10{sup 33} erg s{sup -1} at the assumed distance of 1.5 kpc.« less

Hard X-ray quiescent emission in magnetars via resonant Compton upscattering

NASA Astrophysics Data System (ADS)

Baring, M. G.; Wadiasingh, Z.; Gonthier, P. L.; Harding, A. K.

2017-12-01

Non-thermal quiescent X-ray emission extending between 10 keV and around 150 keV has been seen in about 10 magnetars by RXTE, INTEGRAL, Suzaku, NuSTAR and Fermi-GBM. For inner magnetospheric models of such hard X-ray signals, inverse Compton scattering is anticipated to be the most efficient process for generating the continuum radiation, because the scattering cross section is resonant at the cyclotron frequency. We present hard X-ray upscattering spectra for uncooled monoenergetic relativistic electrons injected in inner regions of pulsar magnetospheres. These model spectra are integrated over bundles of closed field lines and obtained for different observing perspectives. The spectral turnover energies are critically dependent on the observer viewing angles and electron Lorentz factor. We find that electrons with energies less than around 15 MeV will emit most of their radiation below 250 keV, consistent with the turnovers inferred in magnetar hard X-ray tails. Electrons of higher energy still emit most of the radiation below around 1 MeV, except for quasi-equatorial emission locales for select pulse phases. Our spectral computations use a new state-of-the-art, spin-dependent formalism for the QED Compton scattering cross section in strong magnetic fields.

APXS on board Chandrayaan-2 Rover

NASA Astrophysics Data System (ADS)

Shanmugam, M.; Sripada, V. S. Murty; Acharya, Y. B.; Goyal, S. K.

2012-07-01

Alpha Particle X-ray Spectrometer (APXS) is a well proven instrument for quantitative in situ elemental analysis of the planetary surfaces and has been successfully employed for Mars surface exploration. Chandrayaan-2, ISRO's second lunar mission having an Orbiter, Lander and Rover has provided an opportunity to explore the lunar surface with superior detectors such as Silicon Drift Detector (SDD) with energy resolution of about 150eV @ 5.9keV. The objective of the APXS instrument is to analyse several soil/rock samples along the rover traverse for the major elements with characteristic X-rays in 1 to 25keV range. The working principle of APXS involves measuring the intensity of characteristic X-rays emitted from the sample due to Alpha Particle Induced X-ray Emission (PIXE) and X-ray florescence (XRF) processes using suitable radioactive sources, allowing the determination of elements from Na to Br, spanning the energy range of 0.9 to 16keV. For this experiment ^{244}Cm radioactive source has been chosen which emits both Alpha particles (5.8MeV) and X-rays (14.1keV, 18keV). APXS uses six Alpha sources, each about 5mCi activity. Unlike Mars, lunar environment poses additional challenges due to the regolith and extreme surface temperature changes, to operate the APXS. Our APXS instrument consists of two packages namely APXS sensor head and APXS signal electronics. The sensor head assembly contains SDD, six alpha sources and front end electronic circuits such as preamplifier and shaper circuits and will be mounted on a robotic arm which on command brings the sensor head close to the lunar surface at a height of 35±10mm. SDD module to be used in the experiment has 30mm ^{2} active detector area with in-built peltier cooler and heat sink to maintain the detector at about -35°C. The detector is covered with 8 micron thick Be window which results in the low energy threshold of about 1keV. The size of the APXS sensor head is 70x70x70mm ^{3} (approx). APXS signal electronics consists of a PCB having digital, power and rover interface electronics circuits, which are housed inside the Warm Electronics Box (WEB) mounted under the rover chassis where the temperature is maintained between -50°C to +70°C. Presently, we have completed the design verification model of the APXS payload and engineering model of the payload is in progress. The developed system has been tested using laboratory X-ray sources and observed an energy resolution of about 150eV at 5.9keV when the detector is cooled to -35°C. We also carried out the detection of X-ray fluorescence for some of the USGS standards for a fixed geometry of detector, source and sample, using ^{55}Fe and ^{241}Am X-ray sources. It is shown that the count rate of a given peak varies linearly with the concentration of the corresponding element. The detailed developments and results will be discussed at the conference.

Implementation of a preamplifier-amplifier system for radiation detectors used in Mössbauer spectroscopy

NASA Astrophysics Data System (ADS)

Velásquez, A. A.; Arroyave, M.

2014-01-01

We report the assembly and testing of a preamplification and amplification system for pulses produced by gaseous radiation detectors commonly used in Mössbauer spectroscopy. The system is composed by a pair of commercial integrated circuits A203 and A206, which operate as charge sensitive preamplifier-shaping amplifier and linear amplifier-low level discriminator, respectively. The integrated circuits were interconnected in the unipolar output mode and placed inside a metallic shielding, which prevents noise amplification for a suitable signal-noise ratio. The system was tested by irradiating a proportional counter LND-45431 with characteristic X rays of 6.3 keV and gamma rays of 14.4 keV emitted by a Mössbauer radioactive source of 57Co (Rh). Unipolar pulses with Gaussian profile were obtained at the output of the linear amplifier, whose amplitudes were close to 0.4 V for 6.3 keV X rays and 1.4 V for 14.4 keV gamma rays. Pulse height spectra showed that the system allows a satisfactory identification of the X-rays and gamma rays emitted by the 57Co source, giving the possibility to make a good selection of the 14.4 keV peak for having a suitable signal-noise ratio in the Mössbauer spectra. Absorption percentages of 14 % were found by taking the Mössbauer spectra of a natural iron absorber. The assembly and tests of the system are presented through this paper.

High energy X-ray observations of the 38-second pulsar

NASA Technical Reports Server (NTRS)

Byrne, P. F.; Levine, A. M.; Bautz, M.; Howe, S. K.; Lang, F. L.; Primini, F. A.; Lewin, W. H. G.; Gruber, D. E.; Knight, F. K.; Nolan, P. L.

1981-01-01

The results of observations of the 38-second pulsar obtained at high X-ray energies (13-180 keV) with the UCSD/MIT instrument aboard HEAO 1 are reported. The results include a measurement of the source location, measurement of the pulse profile, and determination of the average intensity and spectrum during each of three time intervals spanning a baseline of 1 year. The total intensity of the pulsar is seen to vary on a 6-month time scale. The spectrum is hard but, like other X-ray pulsars, steepens at energies above 20 keV.

An experiment to measure the mass density of a plasma armature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, J.W.; Thomas, K.A.; Clothiaux, E.J.

1991-01-01

In this paper a diagnostic technique for determining the mass density, and possibly the plasma composition, of the plasma armature in the MIDI-3 free-running arc device is described. The armature consists primarily of the components of polythylene and copper, and it can reach velocities in excess of 8 km/sec. The approach in this proof-of-principle experiment utilizes a flash x-ray source with x rays having energies from 3 keV to 20 keV, an elliptical x-ray crystal spectrometer, and an appropriate detector array and data acquisition system.

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

NASA Astrophysics Data System (ADS)

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

2018-06-01

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

6 x 6-cm fully depleted pn-junction CCD for high-resolution spectroscopy in the 0.1- to 15-keV photon energy range

NASA Astrophysics Data System (ADS)

von Zanthier, Christoph; Holl, Peter; Kemmer, Josef; Lechner, Peter; Maier, B.; Soltau, Heike; Stoetter, R.; Braeuninger, Heinrich W.; Dennerl, Konrad; Haberl, Frank; Hartmann, R.; Hartner, Gisela D.; Hippmann, H.; Kastelic, E.; Kink, W.; Krause, N.; Meidinger, Norbert; Metzner, G.; Pfeffermann, Elmar; Popp, M.; Reppin, Claus; Stoetter, Diana; Strueder, Lothar; Truemper, Joachim; Weber, U.; Carathanassis, D.; Engelhard, S.; Gebhart, Th.; Hauff, D.; Lutz, G.; Richter, R. H.; Seitz, H.; Solc, P.; Bihler, Edgar; Boettcher, H.; Kendziorra, Eckhard; Kraemer, J.; Pflueger, Bernhard; Staubert, Ruediger

1998-04-01

The concept and performance of the fully depleted pn- junction CCD system, developed for the European XMM- and the German ABRIXAS-satellite missions for soft x-ray imaging and spectroscopy in the 0.1 keV to 15 keV photon range, is presented. The 58 mm X 60 mm large pn-CCD array uses pn- junctions for registers and for the backside instead of MOS registers. This concept naturally allows to fully deplete the detector volume to make it an efficient detector to photons with energies up to 15 keV. For high detection efficiency in the soft x-ray region down to 100 eV, an ultrathin pn-CCD backside deadlayer has been realized. Each pn-CCD-channel is equipped with an on-chip JFET amplifier which, in combination with the CAMEX-amplifier and multiplexing chip, facilitates parallel readout with a pixel read rate of 3 MHz and an electronic noise floor of ENC < e-. With the complete parallel readout, very fast pn-CCD readout modi can be implemented in the system which allow for high resolution photon spectroscopy of even the brightest x-ray sources in the sky.

Optical Design for a Survey X-Ray Telescope

NASA Technical Reports Server (NTRS)

Saha, Timo T.; Zhang, William W.; McClelland, Ryan S.

2014-01-01

Optical design trades are underway at the Goddard Space Flight Center to define a telescope for an x-ray survey mission. Top-level science objectives of the mission include the study of x-ray transients, surveying and long-term monitoring of compact objects in nearby galaxies, as well as both deep and wide-field x-ray surveys. In this paper we consider Wolter, Wolter-Schwarzschild, and modified Wolter-Schwarzschild telescope designs as basic building blocks for the tightly nested survey telescope. Design principles and dominating aberrations of individual telescopes and nested telescopes are discussed and we compare the off-axis optical performance at 1.0 KeV and 4.0 KeV across a 1.0-degree full field-of-view.

Variability in the x-ray emission of H0538+608: An unusual AM Her-type cataclysmic variable. Thesis, Final Report

NASA Technical Reports Server (NTRS)

Catelli, Jennifer

1992-01-01

The x-ray emissions of AM Herculis-type object H0538+608 were observed using the ROSAT satellite. Evidence was found for a highly varying soft x-ray component with a much lower intensity than is typical for this class. The spectrum was well fit by a thermal bremsstrahlung model (exponential plus gaunt factor) of 35 +/- 5 KeV plus a 0.05 +/- 0.01 KeV blackbody component, with absorption by interstellar medium with a neutral hydrogen column density of log N(sub H) (atoms/sq cm) = 20.2. No obvious periodic variations were found. There was very little correlation between the hard and soft x-ray bands.

POLAR: Design of a novel X-ray polarimeter based on plastic scintillators and MAPMTs

NASA Astrophysics Data System (ADS)

Suarez-Garcia, Estela; Hajdas, Wojtek; Polar Collaboration

2009-10-01

POLAR is a space-borne hard X-ray polarimeter whose design has been optimized to measure the level of linear polarization of gamma-ray bursts (GRB) in the energy range of 50-500 keV. In POLAR, the GRB photons undergo Compton scattering in a target constituted by 1600 plastic scintillator bars. The light output from the whole target is read by 25 multi-anode photomultipliers (MAPMTs). The azimuthal distribution of the scattered photons inside the target provides the information on the GRB polarization. To be able to measure polarization of photons with energy as low as 50 keV, an energy threshold for each single channel of maximum 5 keV is required. This introduces strong constraints in the photon collection efficiency. To maximize it, detailed studies of the scintillator bar surfaces and the available wrapping materials have been performed using both Monte Carlo simulations and laboratory measurements. At present, a POLAR demonstration model (2 of the 25 units of the final design) is being tested in the laboratory. The engineering-qualification model will be ready in 2010.

X-Ray Emission from the Wolf-Rayet Bubble S 308

NASA Technical Reports Server (NTRS)

Toala, J. A.; Guerrero, M. A.; Chu, Y.-H.; Gruendl, R. A.; Arthur, S. J.; Smith, R. C.; Snowden, S. L.

2012-01-01

The Wolf-Rayet (WR) bubble S 308 around the WR star HD 50896 is one of the only two WR bubbles known to possess X-ray emission. We present XMM-Newton observations of three fields of this WR bubble that, in conjunction with an existing observation of its Northwest quadrant (Chu et al. 2003), map most of the nebula. The X-ray emission from S 308 displays a limb-brightened morphology, with a 22' in size central cavity and a shell thickness of approx. 8'. This X-ray shell is confined by the optical shell of ionized material. The spectrum is dominated by the He-like triplets of N VI at approx.0.43 keV and O VII at approx.0.5 keV, and declines towards high energies, with a faint tail up to 1 keV. This spectrum can be described by a two-temperature optically thin plasma emission model (T1 approx.1.1 x 10(exp 6) K, T2 approx.13 x 10(exp 6) K), with a total X-ray luminosity approx.3 x 10(exp 33) erg/s at the assumed distance of 1.8 kpc. Qualitative comparison of the X-ray morphology of S 308 with the results of numerical simulations of wind-blown WR bubbles suggests a progenitor mass of 40 Stellar mass and an age in the WR phase approx.20,000 yrs. The X-ray luminosity predicted by simulatioms including the effects of heat conduction is in agreement with the observations, however, the simulated X-ray spectrum indicates generally hotter gas than is derived from the observations. We suggest that non-equilibrium ionization (NEI) may provide an explanation for this discrepancy.

Bragg crystal spectroscopy on the OSO 8 satellite

NASA Technical Reports Server (NTRS)

Long, K. S.; Chanan, G. A.; Helfand, D. J.; Ku, W. H.-M.; Novick, R.

1979-01-01

Results are reported for high-resolution OSO 8 Bragg-crystal spectroscopy of a variety of cosmic X-ray sources in the energy range from 2 to 10 keV. A continuous spectrum of Sco X-1 is examined, and results of a search for narrow line emission due to iron near 6.7 keV are presented for 32 galactic X-ray sources, including Sco X-1, Cyg X-3, and Cen X-3. It is noted that the strongest evidence for iron line emission has been obtained for Cyg X-3 and that evidence for an iron line feature has also been found in the spectrum of Cen X-3.

Hyper-filter-fluorescer spectrometer for x-rays above 120 keV

DOEpatents

Wang, Ching L.

1983-01-01

An apparatus utilizing filter-fluorescer combinations is provided to measure short bursts of high fluence x-rays above 120 keV energy, where there are no practical absorption edges available for conventional filter-fluorescer techniques. The absorption edge of the prefilter is chosen to be less than that of the fluorescer, i.e., E.sub.PRF E.sub.F. In this way, the response function is virtually zero between E.sub.PRF and E.sub.F and well defined and enhanced in an energy band of less than 1000 keV above the 120 keV energy.

Understanding the X-ray spectrum of anomalous X-ray pulsars and soft gamma-ray repeaters

NASA Astrophysics Data System (ADS)

Guo, Yan-Jun; Dai, Shi; Li, Zhao-Sheng; Liu, Yuan; Tong, Hao; Xu, Ren-Xin

2015-04-01

Hard X-rays above 10 keV are detected from several anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs), and different models have been proposed to explain the physical origin within the frame of either a magnetar model or a fallback disk system. Using data from Suzaku and INTEGRAL, we study the soft and hard X-ray spectra of four AXPs/SGRs: 1RXS J170849-400910, 1E 1547.0-5408, SGR 1806-20 and SGR 0501+4516. It is found that the spectra could be well reproduced by the bulk-motion Comptonization (BMC) process as was first suggested by Trümper et al., showing that the accretion scenario could be compatible with X-ray emission from AXPs/SGRs. Simulated results from the Hard X-ray Modulation Telescope using the BMC model show that the spectra would have discrepancies from the power-law, especially the cutoff at ˜200 keV. Thus future observations will allow researchers to distinguish different models of the hard X-ray emission and will help us understand the nature of AXPs/SGRs. Supported by the National Natural Science Foundation of China.

Element-specific spectral imaging of multiple contrast agents: a phantom study

NASA Astrophysics Data System (ADS)

Panta, R. K.; Bell, S. T.; Healy, J. L.; Aamir, R.; Bateman, C. J.; Moghiseh, M.; Butler, A. P. H.; Anderson, N. G.

2018-02-01

This work demonstrates the feasibility of simultaneous discrimination of multiple contrast agents based on their element-specific and energy-dependent X-ray attenuation properties using a pre-clinical photon-counting spectral CT. We used a photon-counting based pre-clinical spectral CT scanner with four energy thresholds to measure the X-ray attenuation properties of various concentrations of iodine (9, 18 and 36 mg/ml), gadolinium (2, 4 and 8 mg/ml) and gold (2, 4 and 8 mg/ml) based contrast agents, calcium chloride (140 and 280 mg/ml) and water. We evaluated the spectral imaging performances of different energy threshold schemes between 25 to 82 keV at 118 kVp, based on K-factor and signal-to-noise ratio and ranked them. K-factor was defined as the X-ray attenuation in the K-edge containing energy range divided by the X-ray attenuation in the preceding energy range, expressed as a percentage. We evaluated the effectiveness of the optimised energy selection to discriminate all three contrast agents in a phantom of 33 mm diameter. A photon-counting spectral CT using four energy thresholds of 27, 33, 49 and 81 keV at 118 kVp simultaneously discriminated three contrast agents based on iodine, gadolinium and gold at various concentrations using their K-edge and energy-dependent X-ray attenuation features in a single scan. A ranking method to evaluate spectral imaging performance enabled energy thresholds to be optimised to discriminate iodine, gadolinium and gold contrast agents in a single spectral CT scan. Simultaneous discrimination of multiple contrast agents in a single scan is likely to open up new possibilities of improving the accuracy of disease diagnosis by simultaneously imaging multiple bio-markers each labelled with a nano-contrast agent.

Characterization of a spectroscopic detector for application in x-ray computed tomography

NASA Astrophysics Data System (ADS)

Dooraghi, Alex A.; Fix, Brian J.; Smith, Jerel A.; Brown, William D.; Azevedo, Stephen G.; Martz, Harry E.

2017-09-01

Recent advances in cadmium telluride (CdTe) energy-discriminating pixelated detectors have enabled the possibility of Multi-Spectral X-ray Computed Tomography (MSXCT) to incorporate spectroscopic information into CT. MultiX ME 100 V2 is a CdTe-based spectroscopic x-ray detector array capable of recording energies from 20 to 160 keV in 1.1 keV energy bin increments. Hardware and software have been designed to perform radiographic and computed tomography tasks with this spectroscopic detector. Energy calibration is examined using the end-point energy of a bremsstrahlung spectrum and radioisotope spectral lines. When measuring the spectrum from Am-241 across 500 detector elements, the standard deviation of the peak-location and FWHM measurements are +/- 0.4 and +/- 0.6 keV, respectively. As these values are within the energy bin size (1.1 keV), detector elements are consistent with each other. The count rate is characterized, using a nonparalyzable model with a dead time of 64 +/- 5 ns. This is consistent with the manufacturer's quoted per detector-element linear-deviation at 2 Mpps (million photons per sec) of 8.9 % (typical) and 12 % (max). When comparing measured and simulated spectra, a low-energy tail is visible in the measured data due to the spectral response of the detector. If no valid photon detections are expected in the low-energy tail, then a background subtraction may be applied to allow for a possible first-order correction. If photons are expected in the low-energy tail, a detailed model must be implemented. A radiograph of an aluminum step wedge with a maximum height of 20 mm shows an underestimation of attenuation by about 10 % at 60 keV. This error is due to partial energy deposition from higher energy (>60 keV) photons into a lower-energy ( 60 keV) bin, reducing the apparent attenuation. A radiograph of a polytetrafluoroethylene (PTFE) cylinder taken using a bremsstrahlung spectrum from an x-ray voltage of 100 kV filtered by 1.3 mm Cu is reconstructed using Abel inversion. As no counts are expected in the low energy tail, a first order background correction is applied to the spectrum. The measured linear attenuation coefficient (LAC) is within 10% of the expected value in the 60 to 100 keV range. Below 60 keV, low counts in the corrected spectrum and partial energy deposition from incident photons of energy greater than 60 keV into energy bins below 60 keV impact the LAC measurements. This report ends with a demonstration of the tomographic capability of the system. The quantitative understanding of the detector developed in this report will enable further study in evaluating the system for characterization of an object's chemical make-up for industrial and security purposes.

Characterization of a spectroscopic detector for application in x-ray computed tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooraghi, A. A.; Fix, B. J.; Smith, J. A.

Recent advances in cadmium telluride (CdTe) energy-discriminating pixelated detectors have enabled the possibility of Multi-Spectral X-ray Computed Tomography (MSXCT) to incorporate spectroscopic information into CT. MultiX ME 100 V2 is a CdTe-based spectroscopic x-ray detector array capable of recording energies from 20 to 160 keV in 1.1 keV energy bin increments. Hardware and software have been designed to perform radiographic and computed tomography tasks with this spectroscopic detector. Energy calibration is examined using the end-point energy of a bremsstrahlung spectrum and radioisotope spectral lines. When measuring the spectrum from Am-241 across 500 detector elements, the standard deviation of the peak-locationmore » and FWHM measurements are ±0.4 and ±0.6 keV, respectively. As these values are within the energy bin size (1.1 keV), detector elements are consistent with each other. The count rate is characterized, using a nonparalyzable model with a dead time of 64 ± 5 ns. This is consistent with the manufacturer’s quoted per detector-element linear-deviation at 2 Mpps (million photons per sec) of 8.9% (typical) and 12% (max). When comparing measured and simulated spectra, a low-energy tail is visible in the measured data due to the spectral response of the detector. If no valid photon detections are expected in the low-energy tail, then a background subtraction may be applied to allow for a possible first-order correction. If photons are expected in the low-energy tail, a detailed model must be implemented. A radiograph of an aluminum step wedge with a maximum height of about 20 mm shows an underestimation of attenuation by about 10% at 60 keV. This error is due to partial energy deposition from higher-energy (> 60 keV) photons into a lower-energy (~60 keV) bin, reducing the apparent attenuation. A radiograph of a PTFE cylinder taken using a bremsstrahlung spectrum from an x-ray voltage of 100 kV filtered by 1.3 mm Cu is reconstructed using Abel inversion. As no counts are expected in the low energy tail, a first order background correction is applied to the spectrum. The measured linear attenuation coefficient (LAC) is within 10% of the expected value in the 60 to 100 keV range. Below 60 keV, low counts in the corrected spectrum and partial energy deposition from incident photons of energy greater than 60 keV into energy bins below 60 keV impact the LAC measurements. This report ends with a demonstration of the tomographic capability of the system. The quantitative understanding of the detector developed in this report will enable further study in evaluating the system for characterization of an object’s chemical make-up for industrial and security purposes.« less

A deep X-ray view of the bare AGN Ark 120. IV. XMM-Newton and NuSTAR spectra dominated by two temperature (warm, hot) Comptonization processes

NASA Astrophysics Data System (ADS)

Porquet, D.; Reeves, J. N.; Matt, G.; Marinucci, A.; Nardini, E.; Braito, V.; Lobban, A.; Ballantyne, D. R.; Boggs, S. E.; Christensen, F. E.; Dauser, T.; Farrah, D.; Garcia, J.; Hailey, C. J.; Harrison, F.; Stern, D.; Tortosa, A.; Ursini, F.; Zhang, W. W.

2018-01-01

Context. The physical characteristics of the material closest to supermassive black holes (SMBHs) are primarily studied through X-ray observations. However, the origins of the main X-ray components such as the soft X-ray excess, the Fe Kα line complex, and the hard X-ray excess are still hotly debated. This is particularly problematic for active galactic nuclei (AGN) showing a significant intrinsic absorption, either warm or neutral, which can severely distort the observed continuum. Therefore, AGN with no (or very weak) intrinsic absorption along the line of sight, so-called "bare AGN", are the best targets to directly probe matter very close to the SMBH. Aims: We perform an X-ray spectral analysis of the brightest and cleanest bare AGN known so far, Ark 120, in order to determine the process(es) at work in the vicinity of the SMBH. Methods: We present spectral analyses of data from an extensive campaign observing Ark 120 in X-rays with XMM-Newton (4 × 120 ks, 2014 March 18-24), and NuSTAR (65.5 ks, 2014 March 22). Results: During this very deep X-ray campaign, the source was caught in a high-flux state similar to the earlier 2003 XMM-Newton observation, and about twice as bright as the lower-flux observation in 2013. The spectral analysis confirms the "softer when brighter" behavior of Ark 120. The four XMM-Newton/pn spectra are characterized by the presence of a prominent soft X-ray excess and a significant Fe Kα complex. The continuum is very similar above about 3 keV, while significant variability is present for the soft X-ray excess. We find that relativistic reflection from a constant-density, flat accretion disk cannot simultaneously produce the soft excess, broad Fe Kα complex, and hard X-ray excess. Instead, Comptonization reproduces the broadband (0.3-79 keV) continuum well, together with a contribution from a mildly relativistic disk reflection spectrum. Conclusions: During this 2014 observational campaign, the soft X-ray spectrum of Ark 120 below 0.5 keV was found to be dominated by Comptonization of seed photons from the disk by a warm (kTe 0.5 keV), optically-thick corona (τ 9). Above this energy, the X-ray spectrum becomes dominated by Comptonization from electrons in a hot optically thin corona, while the broad Fe Kα line and the mild Compton hump result from reflection off the disk at several tens of gravitational radii.

X-ray emission from the Pleiades cluster

NASA Technical Reports Server (NTRS)

Agrawal, P. C.; Singh, K. P.; Riegler, G. R.

1983-01-01

The detection and identification of H0344+24, a new X-ray source located in the Pleiades cluster, is reported, based on observations made with HEAO A-2 low-energy detector 1 in the 0.15-3.0-keV energy band in August, 1977. The 90-percent-confidence error box for the new source is centered at 03 h 44.1 min right ascension (1950), near the center star of the 500-star Pleiades cluster, 25-eta-Tau. Since no likely galactic or extragalactic source of X-rays was found in a catalog search of the error-box region, identification of the source with the Pleiades cluster is considered secure. X-ray luminosity of the source is calculated to be about 10 to the 32nd ergs/sec, based on a distance of 125 pc. The X-ray characteristics of the Pleiades stars are discussed, and it is concluded that H0344+24 can best be explained as the integrated X-ray emission of all the B and F stars in the cluster.

Low-energy proton induced M X-ray production cross sections for 70Yb, 81Tl and 82Pb

NASA Astrophysics Data System (ADS)

Shehla; Mandal, A.; Kumar, Ajay; Roy Chowdhury, M.; Puri, Sanjiv; Tribedi, L. C.

2018-07-01

The cross sections for production of Mk (k = Mξ, Mαβ, Mγ, Mm1) X-rays of 70Yb, 81Tl and 82Pb induced by 50-250 keV protons have been measured in the present work. The experimental cross sections have been compared with the earlier reported values and those calculated using the ionization cross sections based on the ECPSSR (Perturbed (P) stationary(S) state(S), incident ion energy (E) loss, Coulomb (C) deflection and relativistic (R) correction) model, the X-ray emission rates based on the Dirac-Fock model, the fluorescence and Coster-Kronig yields based on the Dirac-Hartree-Slater (DHS) model. In addition, the present measured proton induced X-ray production cross sections have also been compared with those calculated using the Dirac-Hartree-Slater (DHS) model based ionization cross sections and those based on the Plane wave Born Approximation (PWBA). The measured M X-ray production cross sections are, in general, found to be higher than the ECPSSR and DHS model based values and lower than the PWBA model based cross sections.

Characterization of an in-vacuum PILATUS 1M detector.

PubMed

Wernecke, Jan; Gollwitzer, Christian; Müller, Peter; Krumrey, Michael

2014-05-01

A dedicated in-vacuum X-ray detector based on the hybrid pixel PILATUS 1M detector has been installed at the four-crystal monochromator beamline of the PTB at the electron storage ring BESSY II in Berlin, Germany. Owing to its windowless operation, the detector can be used in the entire photon energy range of the beamline from 10 keV down to 1.75 keV for small-angle X-ray scattering (SAXS) experiments and anomalous SAXS at absorption edges of light elements. The radiometric and geometric properties of the detector such as quantum efficiency, pixel pitch and module alignment have been determined with low uncertainties. The first grazing-incidence SAXS results demonstrate the superior resolution in momentum transfer achievable at low photon energies.

Complex optical/UV and X-ray variability of the Seyfert 1 galaxy 1H 0419-577

NASA Astrophysics Data System (ADS)

Pal, Main; Dewangan, Gulab C.; Kembhavi, Ajit K.; Misra, Ranjeev; Naik, Sachindra

2018-01-01

We present detailed broad-band UV/optical to X-ray spectral variability of the Seyfert 1 galaxy 1H 0419-577 using six XMM-Newton observations performed during 2002-2003. These observations covered a large amplitude variability event in which the soft X-ray (0.3-2 keV) count rate increased by a factor of ∼4 in six months. The X-ray spectra during the variability are well described by a model consisting of a primary power law, blurred and distant reflection. The 2-10 keV power-law flux varied by a factor of ∼7 while the 0.3-2 keV soft X-ray excess flux derived from the blurred reflection component varied only by a factor of ∼2. The variability event was also observed in the optical and UV bands but the variability amplitudes were only at the 6-10 per cent level. The variations in the optical and UV bands appear to follow the variations in the X-ray band. During the rising phase, the optical bands appear to lag behind the UV band but during the declining phase, the optical bands appear to lead the UV band. Such behaviour is not expected in the reprocessing models where the optical/UV emission is the result of reprocessing of X-ray emission in the accretion disc. The delayed contribution of the broad emission lines in the UV band or the changes in the accretion disc/corona geometry combined with X-ray reprocessing may give rise to the observed behaviour of the variations.

Forward directed x-ray from source produced by relativistic electrons from a Self-Modulated Laser Wakefield Accelerator

NASA Astrophysics Data System (ADS)

Lemos, Nuno; Albert, Felicie; Shaw, Jessica; King, Paul; Milder, Avi; Marsh, Ken; Pak, Arthur; Joshi, Chan

2017-10-01

Plasma-based particle accelerators are now able to provide the scientific community with novel light sources. Their applications span many disciplines, including high-energy density sciences, where they can be used as probes to explore the physics of dense plasmas and warm dense matter. A recent advance is in the experimental and theoretical characterization of x-ray emission from electrons in the self-modulated laser wakefield regime (SMLWFA) where little is known about the x-ray properties. A series of experiments at the LLNL Jupiter Laser Facility, using the 1 ps 150 J Titan laser, have demonstrated low divergence electron beams with energies up to 300 MeV and 6 nCs of charge, and betatron x-rays with critical energies up to 20 keV. This work identifies two other mechanisms which produce high energy broadband x-rays and gamma-rays from the SMLWFA: Bremsstrahlung and inverse Compton scattering. We demonstrate the use of Compton scattering and bremsstrahlung to generate x/Gamma-rays from 3 keV up to 1.5 MeV with a source size of 50um and a divergence of 100 mrad. This work is an important step towards developing this x-ray light source on large-scale international laser facilities, and also opens up the prospect of using them for applications. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under the contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC.

Millimeter, microwave, hard X-ray, and soft X-ray observations of energetic electron populations in solar flares

NASA Technical Reports Server (NTRS)

Kundu, M. R.; White, S. M.; Gopalswamy, N.; Lim, J.

1994-01-01

We present comparisons of multiwavelength data for a number of solar flares observed during the major campaign of 1991 June. The different wavelengths are diagnostics of energetic electrons in different energy ranges: soft X-rays are produced by electrons with energies typically below 10 keV, hard X-rays by electrons with energies in the range 10-200 keV, microwaves by electrons in the range 100 keV-1 MeV, and millimeter-wavelength emission by electrons with energies of 0.5 MeV and above. The flares in the 1991 June active period were remarkable in two ways: all have very high turnover frequencies in their microwave spectra, and very soft hard X-ray spectra. The sensitivity of the microwave and millimeter data permit us to study the more energetic (greater than 0.3 MeV) electrons even in small flares, where their high-energy bremsstrahlung is too weak for present detectors. The millimeter data show delays in the onset of emission with respect to the emissions associated with lower energy electrons and differences in time profiles, energy spectral indices incompatible with those implied by the hard X-ray data, and a range of variability of the peak flux in the impulsive phase when compared with the peak hard X-ray flux which is two orders of magnitude larger than the corresponding variability in the peak microwave flux. All these results suggest that the hard X-ray-emitting electrons and those at higher energies which produce millimeter emission must be regarded as separate populations. This has implications for the well-known 'number problem' found previously when comparing the numbers of non thermal electrons required to produce the hard X-ray and radio emissions.

The 3CR Chandra Snapshot Survey: Extragalactic Radio Sources with Redshifts between 1 and 1.5

NASA Astrophysics Data System (ADS)

Stuardi, C.; Missaglia, V.; Massaro, F.; Ricci, F.; Liuzzo, E.; Paggi, A.; Kraft, R. P.; Tremblay, G. R.; Baum, S. A.; O’Dea, C. P.; Wilkes, B. J.; Kuraszkiewicz, J.; Forman, W. R.; Harris, D. E.

2018-04-01

The aim of this paper is to present an analysis of newly acquired X-ray observations of 16 extragalactic radio sources listed in the Third Cambridge Revised (3CR) catalog and not previously observed by Chandra. Observations were performed during Chandra Cycle 17, extending X-ray coverage for the 3CR extragalactic catalog up to z = 1.5. Among the 16 targets, two lie at z < 0.5 (3CR 27 at z = 0.184 and 3CR 69 at z = 0.458) all of the remaining 14 have redshifts between 1.0 and 1.5. In the current sample, there are three compact steep spectrum (CSS) sources, three quasars, and an FR I radio galaxy, while the other nine are FR II radio galaxies. All radio sources have an X-ray counterpart. We measured nuclear X-ray fluxes as well as X-ray emission associated with radio jet knots, hotspots, or lobes in three energy bands: soft (0.5–1 keV), medium (1–2 keV), and hard (2–7 keV). We also performed standard X-ray spectral analysis for the four brightest nuclei. We discovered X-ray emission associated with the radio lobe of 3CR 124, a hotspot of the quasar 3CR 220.2, another hotspot of the radio galaxy 3CR 238, and the jet knot of 3CR 297. We also detected extended X-ray emission around the nuclear region of 3CR 124 and 3CR 297 on scales of several tens of kiloparsecs. Finally, we present an update on the X-ray observations performed with Chandra and XMM-Newton on the entire 3CR extragalactic catalog.

The microchannel x-ray telescope status

NASA Astrophysics Data System (ADS)

Götz, D.; Meuris, A.; Pinsard, F.; Doumayrou, E.; Tourrette, T.; Osborne, J. P.; Willingale, R.; Sykes, J. M.; Pearson, J. F.; Le Duigou, J. M.; Mercier, K.

2016-07-01

We present design status of the Microchannel X-ray Telescope, the focussing X-ray telescope on board the Sino- French SVOM mission dedicated to Gamma-Ray Bursts. Its optical design is based on square micro-pore optics (MPOs) in a Lobster-Eye configuration. The optics will be coupled to a low-noise pnCCD sensitive in the 0.2{10 keV energy range. With an expected point spread function of 4.5 arcmin (FWHM) and an estimated sensitivity adequate to detect all the afterglows of the SVOM GRBs, MXT will be able to provide error boxes smaller than 60 (90% c.l.) arc sec after five minutes of observation.

NuSTAR Observations of Magnetar 1E 1841-045

NASA Astrophysics Data System (ADS)

An, Hongjun; Hascoët, Romain; Kaspi, Victoria M.; Beloborodov, Andrei M.; Dufour, François; Gotthelf, Eric V.; Archibald, Robert; Bachetti, Matteo; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Greffenstette, Brian W.; Hailey, Charles J.; Harrison, Fiona A.; Kitaguchi, Takao; Kouveliotou, Chryssa; Madsen, Kristin K.; Markwardt, Craig B.; Stern, Daniel; Vogel, Julia K.; Zhang, William W.

2013-12-01

We report new spectral and temporal observations of the magnetar 1E 1841-045 in the Kes 73 supernova remnant obtained with the Nuclear Spectroscopic Telescope Array. Combined with new Swift and archival XMM-Newton and Chandra observations, the phase-averaged spectrum is well characterized by a blackbody plus double power law, in agreement with previous multimission X-ray results. However, we are unable to reproduce the spectral results reported based on Suzaku observations. The pulsed fraction of the source is found to increase with photon energy. The measured rms pulsed fractions are ~12% and ~17% at ~20 and ~50 keV, respectively. We detect a new feature in the 24-35 keV band pulse profile that is uniquely double peaked. This feature may be associated with a possible absorption or emission feature in the phase-resolved spectrum. We fit the X-ray data using the recently developed electron-positron outflow model by Beloborodov for the hard X-ray emission from magnetars. This produces a satisfactory fit, allowing a constraint on the angle between the rotation and magnetic axes of the neutron star of ~20° and on the angle between the rotation axis and line of sight of ~50°. In this model, the soft X-ray component is inconsistent with a single blackbody; adding a second blackbody or a power-law component fits the data. The two-blackbody interpretation suggests a hot spot of temperature kT ≈ 0.9 keV occupying ~1% of the stellar surface.

NuSTAR OBSERVATIONS OF THE COMPTON-THICK ACTIVE GALACTIC NUCLEUS AND ULTRALUMINOUS X-RAY SOURCE CANDIDATE IN NGC 5643

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annuar, A.; Gandhi, P.; Alexander, D. M.

2015-12-10

We present two Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the local Seyfert 2 active galactic nucleus (AGN) and an ultraluminous X-ray source (ULX) candidate in NGC 5643. Together with archival data from Chandra, XMM-Newton, and Swift-BAT, we perform a high-quality broadband spectral analysis of the AGN over two decades in energy (∼0.5–100 keV). Previous X-ray observations suggested that the AGN is obscured by a Compton-thick (CT) column of obscuring gas along our line of sight. However, the lack of high-quality ≳10 keV observations, together with the presence of a nearby X-ray luminous source, NGC 5643 X–1, have left significantmore » uncertainties in the characterization of the nuclear spectrum. NuSTAR now enables the AGN and NGC 5643 X–1 to be separately resolved above 10 keV for the first time and allows a direct measurement of the absorbing column density toward the nucleus. The new data show that the nucleus is indeed obscured by a CT column of N{sub H} ≳ 5 × 10{sup 24} cm{sup −2}. The range of 2–10 keV absorption-corrected luminosity inferred from the best-fitting models is L{sub 2–10,int} = (0.8–1.7) × 10{sup 42} erg s{sup −1}, consistent with that predicted from multiwavelength intrinsic luminosity indicators. In addition, we also study the NuSTAR data for NGC 5643 X–1 and show that it exhibits evidence of a spectral cutoff at energy E ∼ 10 keV, similar to that seen in other ULXs observed by NuSTAR. Along with the evidence for significant X-ray luminosity variations in the 3–8 keV band from 2003 to 2014, our results further strengthen the ULX classification of NGC 5643 X–1.« less

The hard x-ray imager (HXI) onboard ASTRO-H

NASA Astrophysics Data System (ADS)

Nakazawa, Kazuhiro; Sato, Goro; Kokubun, Motohide; Enoto, Teruaki; Fukazawa, Yasushi; Hagino, Kouichi; Harayama, Atsushi; Hayashi, Katsuhiro; Kataoka, Jun; Katsuta, Junichiro; Laurent, Philippe; Lebrun, François; Limousin, Olivier; Makishima, Kazuo; Mizuno, Tsunefumi; Mori, Kunishiro; Nakamori, Takeshi; Nakano, Toshio; Noda, Hirofumi; Odaka, Hirokazu; Ohno, Masanori; Ohta, Masayuki; Saito, Shinya; Sato, Rie; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shin'ichiro; Terada, Yukikatsu; Uchiyama, Hideki; Uchiyama, Yasunobu; Watanabe, Shin; Yamaoka, Kazutaka; Yatsu, Yoichi; Yuasa, Takayuki

2016-07-01

Hitomi X-ray observatory launched in 17 February 2016 had a hard X-ray imaging spectroscopy system made of two hard X-ray imagers (HXIs) coupled with two hard X-ray telescopes (HXTs). With 12 m focal length, they provide fine (2' half-power diameter; HPD) imaging spectroscopy at 5 to 80 keV. The HXI main imagers are made of 4 layers of Si and a CdTe semiconductor double-sided strip detectors, stacked to enhance detection efficiency as well as to enable photon interaction-depth sensing. Active shield made of 9 BGO scintillators surrounds the imager to provide with low background. Following the deployment of the Extensible Optical Bench (EOB) on 28 February, the HXI was gradually turned on. Two imagers successfully started observation on 14 March, and was operational till the incident lead to Hitomo loss, on 26 March. All detector channels, 1280 ch of imager and 11 channel of active shields and others each, worked well and showed performance consistent with those seen on ground. From the first light observation of G21.5-0.9 and the following Crab observations, 5-80 keV energy coverage and good detection efficiency were confirmed. With blank sky observations, we checked our background level. In some geomagnetic region, strong background continuum, presumably caused by trapped electron with energy 100 keV, is seen. But by cutting the high-background time-intervals, the background became significantly lower, typically with 1-3 x 10-4 counts s-1 keV-1 cm-2 (here cm2 is shown with detector geometrical area). Above 30 keV, line and continuum emission originating from activation of CdTe was significantly seen, though the level of 1-4 x 10-4 counts s-1 keV-1 cm-2 is still comparable to those seen in NuSTAR. By comparing the effective area and background rate, preliminary analysis shows that the HXI had a statistical sensitivity similar to NuSTAR for point sources, and more than twice better for largely extended sources.

The Instruments and Capabilities of the Miniature X-Ray Solar Spectrometer (MinXSS) CubeSats

NASA Astrophysics Data System (ADS)

Moore, Christopher S.; Caspi, Amir; Woods, Thomas N.; Chamberlin, Phillip C.; Dennis, Brian R.; Jones, Andrew R.; Mason, James P.; Schwartz, Richard A.; Tolbert, Anne K.

2018-02-01

The Miniature X-ray Solar Spectrometer (MinXSS) CubeSat is the first solar science oriented CubeSat mission flown for the NASA Science Mission Directorate, with the main objective of measuring the solar soft X-ray (SXR) flux and a science goal of determining its influence on Earth's ionosphere and thermosphere. These observations can also be used to investigate solar quiescent, active region, and flare properties. The MinXSS X-ray instruments consist of a spectrometer, called X123, with a nominal 0.15 keV full-width at half-maximum (FWHM) resolution at 5.9 keV and a broadband X-ray photometer, called XP. Both instruments are designed to obtain measurements from 0.5 - 30 keV at a nominal time cadence of 10 s. A description of the MinXSS instruments, performance capabilities, and relation to the Geostationary Operational Environmental Satellite (GOES) 0.1 - 0.8 nm flux is given in this article. Early MinXSS results demonstrate the capability of measuring variations of the solar spectral soft X-ray (SXR) flux between 0.8 - 12 keV from at least GOES A5-M5 (5 × 10^{-8} - 5 ×10^{-5} W m^{-2}) levels and of inferring physical properties (temperature and emission measure) from the MinXSS data alone. Moreover, coronal elemental abundances can be inferred, specifically for Fe, Ca, Si, Mg, S, Ar, and Ni, when the count rate is sufficiently high at each elemental spectral feature. Additionally, temperature response curves and emission measure loci demonstrate the MinXSS sensitivity to plasma emission at different temperatures. MinXSS observations coupled with those from other solar observatories can help address some of the most compelling questions in solar coronal physics. Finally, simultaneous observations by MinXSS and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) can provide the most spectrally complete soft X-ray solar flare photon flux measurements to date.

The broad-band x ray spectral variability of Mkn 841

NASA Technical Reports Server (NTRS)

George, I. M.; Nandra, K.; Fabian, A. C.; Turner, T. J.; Done, C.; Day, C. S. R.

1992-01-01

The results of a detailed spectral analysis of four X-ray observations of the luminous Seyfert 1.5 galaxy Mkn 841 performed using the EXOSAT and Ginga satellites over the period June 1984 to July 1990 are reported. Preliminary results from a short ROSAT PSPC observation of Mkn 841 in July 1990 are also presented. Variability is apparent in both the soft (0.1-1.0 keV) and medium (1-20 keV) energy bands. Above 1 keV, the spectra are adequately modelled by a power-law with a strong emission line of equivalent width approximately 450 eV. The energy of the line (approximately 6.4 keV) is indicative of K-shell fluorescence from neutral iron, leading to the interpretation that the line arises via X-ray illumination of cold material surrounding the source. In addition to the flux variability, the continuum shape also changes in a dramatic fashion, with variations in the apparent photon index Delta(Gamma) approximately 0.6. The large equivalent width of the emission line clearly indicates a strongly enhanced reflection component in the source, compared to other Seyferts observed with Ginga. The spectral changes are interpreted in terms of a variable power-law continuum superimposed on a flatter reflection component. For one Ginga observation, the reflected flux appears to dominate the medium energy X-ray emission, resulting in an unusually flat slope (Gamma approximately 1.0). The soft X-ray excess is found to be highly variable by a factor approximately 10. These variations are not correlated with the hard flux, but it seems likely that the soft component arises via reprocessing of the hard X-rays. We find no evidence for intrinsic absorption, with the equivalent hydrogen column density constrained to be less than or equal to few x 10(exp 20) cm(exp -2). The implications of these results for physical models for the emission regions in this and other X-ray bright Seyferts are briefly discussed.

The Detection of Circumnuclear X-Ray Emission from the Seyfert Galaxy NGC 3516

NASA Technical Reports Server (NTRS)

George, I. M.; Turner, T. J.; Netzer, H.; Kraemer, S. B.; Ruiz, J.; Chelouche, D.; Crenshaw, D. M.; Yaqoob, T.; Nandra, K.; Mushotzky, R. F.;

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Huanjun; Cho, Hyo-Min; Molloi, Sabee, E-mail: symolloi@uci.edu

Purpose: To investigate the feasibility of characterizing a Si strip photon-counting detector using x-ray fluorescence. Methods: X-ray fluorescence was generated by using a pencil beam from a tungsten anode x-ray tube with 2 mm Al filtration. Spectra were acquired at 90° from the primary beam direction with an energy-resolved photon-counting detector based on an edge illuminated Si strip detector. The distances from the source to target and the target to detector were approximately 19 and 11 cm, respectively. Four different materials, containing silver (Ag), iodine (I), barium (Ba), and gadolinium (Gd), were placed in small plastic containers with a diametermore » of approximately 0.7 cm for x-ray fluorescence measurements. Linear regression analysis was performed to derive the gain and offset values for the correlation between the measured fluorescence peak center and the known fluorescence energies. The energy resolutions and charge-sharing fractions were also obtained from analytical fittings of the recorded fluorescence spectra. An analytical model, which employed four parameters that can be determined from the fluorescence calibration, was used to estimate the detector response function. Results: Strong fluorescence signals of all four target materials were recorded with the investigated geometry for the Si strip detector. The average gain and offset of all pixels for detector energy calibration were determined to be 6.95 mV/keV and −66.33 mV, respectively. The detector’s energy resolution remained at approximately 2.7 keV for low energies, and increased slightly at 45 keV. The average charge-sharing fraction was estimated to be 36% within the investigated energy range of 20–45 keV. The simulated detector output based on the proposed response function agreed well with the experimental measurement. Conclusions: The performance of a spectral imaging system using energy-resolved photon-counting detectors is very dependent on the energy calibration of the detector. The proposed x-ray fluorescence technique offers an accurate and efficient way to calibrate the energy response of a photon-counting detector.« less

NuSTAR Detection of a Hard X-Ray Source in the Supernova Remnant-molecular Cloud Interaction Site of IC 443

NASA Astrophysics Data System (ADS)

Zhang, Shuo; Tang, Xiaping; Zhang, Xiao; Sun, Lei; Gotthelf, Eric V.; Zhang, Zhi-Yu; Li, Hui; Cheng, Allen; Pasham, Dheeraj; Baganoff, Frederick K.; Perez, Kerstin; Hailey, Charles J.; Mori, Kaya

2018-06-01

We report on a broadband study of a complex X-ray source (1SAX J0618.0+2227) associated with the interaction site of the supernova remnant (SNR) IC 443 and ambient molecular cloud (MC) using NuSTAR, XMM-Newton, and Chandra observations. Its X-ray spectrum is composed of both thermal and nonthermal components. The thermal component can be equally well represented by either a thin plasma model with kT = 0.19 keV or a blackbody model with kT = 0.11 keV. The nonthermal component can be fit with either a power law with Γ ∼ 1.7 or a cutoff power law with Γ ∼ 1.5 and a cutoff energy at E cut ∼ 18 keV. Using the newly obtained NuSTAR data set, we test three possible scenarios for isolated X-ray sources in the SNR–MC interaction site: (1) a pulsar wind nebula (PWN); (2) an SNR ejecta fragment; and (3) a shocked molecular clump. We conclude that this source is most likely composed of an SNR ejecta (or a PWN) and surrounding shocked molecular clumps. The nature of this hard X-ray source in the SNR–MC interaction site of IC 443 may shed light on unidentified X-ray sources with hard X-ray spectra in rich environments for star-forming regions, such as the Galactic center.

Multi-energy x-ray detector calibration for T e and impurity density (n Z) measurements of MCF plasmas

DOE PAGES

Maddox, J.; Pablant, N.; Efthimion, P.; ...

2016-09-07

Here, soft x-ray detection with the new "multi-energy" PILATUS3 detector systems holds promise as a magnetically confined fusion (MCF) plasma diagnostic for ITER and beyond. The measured x-ray brightness can be used to determine impurity concentrations, electron temperatures, n 2 eZ eff products, and to probe the electron energy distribution. However, in order to be effective, these detectors which are really large arrays of detectors with photon energy gating capabilities must be precisely calibrated for each pixel. The energy-dependence of the detector response of the multi-energy PILATUS3 system with 100 K pixels has been measured at Dectris Laboratory. X-rays emittedmore » from a tube under high voltage bombard various elements such that they emit x-ray lines from Zr-Lα to Ag-Kα between 1.8 and 22.16 keV. Each pixel on the PILATUS3 can be set to a minimum energy threshold in the range from 1.6 to 25 keV. This feature allows a single detector to be sensitive to a variety of x-ray energies, so that it is possible to sample the energy distribution of the x-ray continuum and line-emission. PILATUS3 can be configured for 1D or 2D imaging of MCF plasmas with typical spatial energy and temporal resolution of 1 cm, 0.6 keV, and 5 ms, respectively.« less

Thick-target-method study of Mα β x-ray production cross sections of Pb and Bi impacted by positrons up to 9 keV

NASA Astrophysics Data System (ADS)

Wu, Y.; Liang, Y.; Xu, M. X.; Yuan, Y.; Chang, C. H.; Qian, Z. C.; Wang, B. Y.; Kuang, P.; Zhang, P.

2018-03-01

Atomic M -shell x-ray production cross sections induced by positrons near the threshold energy have been presented in this paper. In the experiment, online monitoring technology, which utilizes a high-purity germanium detector to record the annihilation photons emitted from the pure thick target impacted by positrons, was developed to obtain the accurate number of the incident positrons. The effects of the multiple scattering of incident positrons, from the bremsstrahlung and annihilation photons and other secondary particles on the experimental characteristic x-ray yield, were eliminated by Monte Carlo simulation in combination with theoretical integral calculation. The Tikhonov regularization method was adopted to handle the ill-posed inverse problem involved in the thick-target method, i.e., x-ray production cross sections by the corrected characteristic x-ray yield. Experimental results of Mα β x-ray production cross sections for Pb and Bi impacted by 6-9-keV positrons were compared with the corresponding values predicted by the distorted-wave Born approximation (DWBA). Good agreement was found between the two. Moreover, we have presented the experimental results on the ratios of the Mα β x-ray production cross sections by electron impact in the literature to that by 6-9-keV positron impact in this work. They were also in accordance with the theoretical ratios calculated by the predictions of DWBA theory.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shidatsu, M.; Ueda, Y.; Fabrika, S., E-mail: megumi.shidatsu@riken.jp

We report on an X-ray observing campaign of the ultraluminous X-ray source IC 342 X-1 with NuSTAR and Swift in 2016 October, in which we captured the very moment when the source showed spectral variation. The Swift/XRT spectrum obtained in October 9–11 has a power-law shape and is consistent with those observed in the coordinated XMM-Newton and NuSTAR observations in 2012. In October 16–17, when the 3–10 keV flux became ≈4 times higher, we performed simultaneous NuSTAR and Swift observations. In this epoch, the source showed a more round-shaped spectrum like that seen with ASCA 23 years ago. Thanks tomore » the wide energy coverage and high sensitivity of NuSTAR , we obtained hard X-ray data covering up to ∼30 keV for the first time during the high-luminosity state of IC 342 X-1. The observed spectrum has a broader profile than the multi-color disk blackbody model. The X-ray flux decreased again in the last several hours of the NuSTAR observation, when the spectral shape approached those seen in 2012 and 2016 October 9–11. The spectra obtained in our observations and in 2012 can be commonly described with disk emission and its Comptonization in cool ( T {sub e} ≈ 4 keV), optically thick ( τ ≈ 5) plasma. The spectral turnover seen at around 5–10 keV shifts to higher energies as the X-ray luminosity decreases. This behavior is consistent with that predicted from recent numerical simulations of super-Eddington accretion flows with Compton-thick outflows. We suggest that the spectral evolution observed in IC 342 X-1 can be explained by a smooth change in mass-accretion rate.« less

Chandra Reveals Heavy Obscuration and Circumnuclear Star Formation in Seyfert 2 Galaxy NGC 4968

NASA Technical Reports Server (NTRS)

LaMassa, Stephanie M.; Yaqoob, Tahir; Levenson, N. A.; Boorman, Peter; Heckman, Timothy M.; Gandhi, Poshak; Rigby, Jane R.; Urry, C. Megan; Ptak, Andrew F.

2017-01-01

We present the Chandra imaging and spectral analysis of NGC 4968, a nearby (z = 0.00986) Seyfert 2 galaxy. We discover extended (approx. 1 kpc) X-ray emission in the soft band (0.5-2 keV) that is neither coincident with the narrow line region nor the extended radio emission. Based on spectral modeling, it is linked to on-going star formation [approx. 2.6-4 Mass compared to Earth yr(exp.- 1)]. The soft emission at circumnuclear scales (inner approx. 400 pc) originates from hot gas, with kT approx. 0.7 keV, while the most extended thermal emission is cooler (kT approx. 0.3 keV). We refine previous measurements of the extreme Fe K alpha equivalent width in this source (EW 2.5 + 2.6/-1.0 keV), which suggests the central engine is completely embedded within Compton-thick levels of obscuration. Using physically motivated models fit to the Chandra spectrum, we derive a Compton-thick column density [N(sub H) is greater than 1.25× 10(exp 24) cm(exp.- 2)] and an intrinsic hard (2-10 keV) X-ray luminosity of approx. 3-8× 10(exp. 42) erg s(exp. - 1) (depending on the presumed geometry of the obscurer), which is over two orders of magnitude larger than that observed. The large Fe K Alpha EW suggests a spherical covering geometry, which could be confirmed with X-ray measurements above 10 keV. NGC 4968 is similar to other active galaxies that exhibit extreme Fe K Alpha EWs (i.e., greater than 2 keV) in that they also contain on-going star formation. This work supports the idea that gas associated with nuclear star formation may increase the covering factor of the enshrouding gas and play a role in obscuring active galactic nuclei.

Gamma-ray Spectral Characteristics of Thermal and Non-thermal Emission from Three Black Holes

NASA Technical Reports Server (NTRS)

Ling, James C.; Wheaton, William A.

2004-01-01

Cygnus X-1 and the gamma-ray transients GROJ0422+32 and GROJ1719-24 displayed similar spectral properties when they underwent transitions between the high and low gamma-ray (30 keV to few MeV) intensity states. When these sources were in the high (gamma)-ray intensity state ((gamma)2, for Cygnus X-l), their spectra featured two components: a Comptonized shape below 200-300 keV with a soft power-law tail (photon index >= 3) that extended to 1 MeV or beyond. When the sources were in the low-intensity state ((gamma)0, for Cygnus X-l), the Comptonized spectral shape below 200 keV typically vanished and the entire spectrum from 30 keV to 1 MeV can be characterized by a single power law with a relatively harder photon index 2-2.7. Consequently the high- and low-intensity gamma-ray spectra intersect, generally in the 400 KeV - 1 MeV range, in contrast to the spectral pivoting seen previously at lower (10 keV) energies. The presence of the power-law component in both the high- and low-intensity gammaray spectra strongly suggests that the non-thermal process is likely to be at work in both the high and the low-intensity situations. We have suggested a possible scenario (Ling & Wheaton, 2003), by combining the ADAF model of Esin et al. (1998) with a separate jet region that produces the non-thermal gamma-ray emission, and which explains the state transitions. Such a scenario will be discussed in the context of the observational evidence, summarized above, from the database produced by EBOP, JPL's BATSE earth occultation analysis system.

Non-invasive localization of organic matter in soil aggregates using SR-μCT

NASA Astrophysics Data System (ADS)

Peth, Stephan; Mordhorst, Anneka; Chenu, Claire; Uteau Puschmann, Daniel; Garnier, Patricia; Nunan, Naoise; Pot, Valerie; Beckmann, Felix; Ogurreck, Malte

2014-05-01

Knowledge of the location of soil organic matter (SOM) and its spatial association to soil structure is an important step in improving modeling approaches for simulating organic matter turnover processes. Advanced models for carbon mineralization are able to account for the 3D distribution of SOM which is assumed to influence mineralisation. However, their application is still limited by the fact that no method exists to non-invasively determine the 3D spatial distribution of SOM in structured soils. SR-based X-ray microtomography (SR-µCT) is an advanced and promising tool in gaining knowledge on the 3-dimensional organization of soil phases (minerals, organic matter, water, air) which on a voxel level could be implemented into spatially explicit models. However, since the contrast of linear attenuation coefficients of soil organic matter on the one hand and mineral components and water on the other hand are relatively low, especially when materials are finely dispersed, organic matter within the soil pore space is often not resolved in ordinary X-ray absorption contrast imaging. To circumvent this problem we have developed a staining procedure for organic matter using Osmium-tetroxide since Osmium is an element with an absorption edge at a higher X-ray energy level. Osmium is known from transmission electron microscopy analysis (TEM) to stain organic matter specifically and irreversibly while having an absorption edge at approximately 74 keV. We report on the application of a novel Osmium vapor staining method to analyze differences in organic matter content and identify small scale spatial distribution of SOM in soil aggregates. To achieve this we have taken soil aggregate samples (6-8 mm across) obtained from arable soils differing in soil management. Aggregate samples were investigated by synchrotron-based X-ray microtomography (SR-µCT) after staining the sample with Osmium-tetroxide (OsO4) vapor. We utilized the monochromatic X-ray beam to locate osmium bound to SOM in the stained soil aggregate samples by scanning the aggregates at different photon energies: 30 keV at which the attenuation contrast is optimal for distinguishing other soil constituents, 70 keV (below the absorption of osmium) and 78 keV (above the absorption edge of osmium). The results suggest that particulate organic matter, which was not visibly by scanning samples at energy levels optimal for resolving soil structure (30 keV), was identified after osmium staining and scanning the samples at energy levels just below (70 keV) and above (78 keV) the absorption edge of Osmium. Subtracting the images below from the images above the osmium edged we were able to isolate stained particulate organic matter which otherwise would have been wrongly interpreted as pore space without staining. Combining both pore space and organic matter distribution we are able to investigate the association of SOM with soil structure.

Low- to Middle-Latitude X-Ray Emission from Jupiter

NASA Technical Reports Server (NTRS)

Bhardwaj, Anil; Elsner, Ronald F.; Gladstone, G. Randall; Waite, J. Hunter, Jr.; Branduardi-Raymont, Graziella; Cravens, Thomas E.; Ford, Peter G.

2006-01-01

The Chandra X-ray Observatory (CXO) observed Jupiter during the period 24-26 February 2003 for approx. 40 hours (4 Jupiter rotations), using both the spectroscopy array of the Advanced CCD Imaging Spectrometer (ACIS-S) and the imaging array of the High-Resolution Camera (HRC-I). Two ACIS-S exposures, each -8.5 hours long, were separated by an HRC-I exposure of approx. 20 hours. The low- to middle-latitude nonauroral disk X-ray emission is much more spatially uniform than the auroral emission. However, the low- to middle-latitude X-ray count rate shows a small but statistically significant hour angle dependence and depends on surface magnetic field strength. In addition, the X-ray spectra from regions corresponding to 3-5 gauss and 5-7 gauss surface fields show significant differences in the energy band 1.26-1.38 keV, perhaps partly due to line emission occurring in the 3-5 gauss region but not the 5-7 gauss region. A similar correlation of surface magnetic field strength with count rate is found for the 18 December 2000 HRC-I data, at a time when solar activity was high. The low- to middle-latitude disk X-ray count rate observed by the HRC-I in the February 2003 observation is about 50% of that observed in December 2000, roughly consistent with a decrease in the solar activity index (F10.7 cm flux) by a similar amount over the same time period. The low- to middle-latitude X-ray emission does not show any oscillations similar to the approx. 45 min oscillations sometimes seen from the northern auroral zone. The temporal variation in Jupiter's nonauroral X-ray emission exhibits similarities to variations in solar X-ray flux observed by GOES and TIMED/SEE. The two ACIS-S 0.3-2.0 keV low- to middle-latitude X-ray spectra are harder than the auroral spectrum and are different from each other at energies above 0.7 keV, showing variability in Jupiter's nonauroral X-ray emission on a timescale of a day. The 0.3-2.0 keV X-ray power emitted at low to middle latitudes is 0.21 GW and 0.39 GW for the first and second ACIS-S exposures, respectively. We suggest that X-ray emission from Jupiter's disk may be largely generated by the scattering and fluorescence of solar X rays in its upper atmosphere, especially at times of high incident solar X-ray flux. However, the dependence of count rate on surface magnetic-field strength may indicate the presence of some secondary component, possibly ion precipitation from radiation belts close to the planet.

Edge-on illumination photon-counting for medical imaging

NASA Astrophysics Data System (ADS)

Doni, M.; Visser, J.; Koffeman, E.; Herrmann, C.

2015-08-01

In medical X-ray Computed Tomography (CT) a silicon based sensor (300-1000 μm) in face-on configuration does not collect the incoming X-rays effectively because of their high energy (40-140 keV). For example, only 2% of the incoming photons at 100 keV are stopped by a 500 μm thick silicon layer. To increase the efficiency, one possibility is to use materials with higher Z (e.g. GaAs, CZT), which have some drawbacks compared to silicon, such as short carrier lifetime or low mobility. Therefore, we investigate whether illuminating silicon edge-on instead of face-on is a solution. Aim of the project is to find and take advantage of the benefits of this new geometry when used for a pixel detector. In particular, we employ a silicon hybrid pixel detector, which is read out by a chip from the Medipix family. Its capabilities to be energy selective will be a notable advantage in energy resolved (spectral) X-ray CT.

The high-energy X-ray spectrum of black hole candidate GX 339-4 during a transition

NASA Technical Reports Server (NTRS)

Dolan, J. F.; Crannell, C. J.; Dennis, B. R.; Orwig, L. E.

1987-01-01

The X-ray emitting system GX 339-4 contains one of the prime candidates for a stellar mass-sized black hole. Determining the observational similarities and differences between the members of this group is of value in specifying which characteristics can be used to identify systems containing a black hole, especially those for which no mass determination can be made. The first observations of the E greater than 20 keV spectrum of GX 339-4 during a transition between luminosity states are reported here. The hard spectral state is the lower luminosity state of the system. GX 339-4 has a power-low spectrum above 20 keV which pivots during transitions between distinct luminosity states. The only other X-ray sources known to exhibit this behavior, Cyg XR-1 and (probably) A0620-00, are leading candidates for systems containing a black hole component based on their measured spectrocopic mass function.

THE STRUCTURE OF THE LOCAL HOT BUBBLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, W.; Galeazzi, M.; Uprety, Y.

Diffuse X-rays from the Local Galaxy ( DXL ) is a sounding rocket mission designed to quantify and characterize the contribution of Solar Wind Charge eXchange (SWCX) to the Diffuse X-ray Background and study the properties of the Local Hot Bubble (LHB). Based on the results from the DXL mission, we quantified and removed the contribution of SWCX to the diffuse X-ray background measured by the ROSAT All Sky Survey. The “cleaned” maps were used to investigate the physical properties of the LHB. Assuming thermal ionization equilibrium, we measured a highly uniform temperature distributed around kT  = 0.097 keV ± 0.013 keV (FWHM) ± 0.006more » keV (systematic). We also generated a thermal emission measure map and used it to characterize the three-dimensional (3D) structure of the LHB, which we found to be in good agreement with the structure of the local cavity measured from dust and gas.« less

Microcalorimeter X-ray Detectors for Solar Physics

NASA Astrophysics Data System (ADS)

Deiker, S.; Boerner, P.; Martinez-Galarce, D.; Metcalf, T.; Rausch, A.; Shing, L.; Stern, R.; Irwin, K.; William, D.; Reintsema, C.; Ullom, J.; Cabrera, B.; Lehman, S.; Brink, P.

2005-05-01

Cryogenic X-ray microcalorimeters provide high spectral resolution over a large bandwidth. They have achieved < 3 eV resolution at 5.9 keV, and can produce this performance simultaneously from 0.25 to 10 keV. Although they operate at low (< 0.1 K) temperatures, such temperature are now easily produced. Microcalorimeters cooled by adiabatic demagnetization refrigerators have already flown on sounding rocket flights to study the soft X-ray background of the interstellar medium, and will soon be launched on the ASTRO-E II satellite. Microcalorimeters based on superconducting transition edge sensors are multiplexable and may be fabricated using standard photolithographic techniques. This makes large arrays of microcalorimeters feasible. Each pixel of such an array detects the arrival time of each photon to within < 0.01 ms. Such an instrument would offer simultaneous spatial, temporal and energy resolution, bringing a wealth of new information about solar processes. Current design and performance of microcalorimeters will be presented. Future improvements required to optimize microcalorimeters for solar physics applications will also be discussed.

The Miniature X-ray Solar Spectrometer (MinXSS) CubeSats: New soft X-ray spectrometer to investigate properties of hot plasma in the quiet Sun, active regions, and flares.

NASA Astrophysics Data System (ADS)

Moore, C. S.; Dennis, B. R.; Woods, T. N.

2017-12-01

Detection of soft X-rays from the Sun provides direct information on coronal plasma at temperatures in excess of 1 MK. The Miniature X-ray Solar Spectrometer (MinXSS) CubeSats provides new spectrally resolved measurements from 0.8 -12 keV. The MinXSS spectral resolving power (R 40 at 5.9 keV) allows plasma abundances to be determined for Fe, Mg, Ni, Ca, Si, S, and Ar. Long-term temporal variations during quiet-Sun times allow active region contributions to be extracted from the full solar flux. The MinXSS 10 second time cadence allows short-term variations of the soft X-ray flux, temperature, and abundances to be determined during flares. The MinXSS spectroscopic observations, combined with the imaging spectroscopy from the Hinode X-ray Telescope (XRT) and the Reuven Ramaty Solar Spectroscopic Imager (RHESSI), hold great potential for advancing our understanding of solar dynamics.

Tunable all-optical quasimonochromatic thomson x-ray source in the nonlinear regime.

PubMed

Khrennikov, K; Wenz, J; Buck, A; Xu, J; Heigoldt, M; Veisz, L; Karsch, S

2015-05-15

We present an all-laser-driven, energy-tunable, and quasimonochromatic x-ray source based on Thomson scattering from laser-wakefield-accelerated electrons. One part of the laser beam was used to drive a few-fs bunch of quasimonoenergetic electrons, while the remainder was backscattered off the bunch at weakly relativistic intensity. When the electron energy was tuned from 17-50 MeV, narrow x-ray spectra peaking at 5-42 keV were recorded with high resolution, revealing nonlinear features. We present a large set of measurements showing the stability and practicality of our source.

Characterization of energy response for photon-counting detectors using x-ray fluorescence

PubMed Central

Ding, Huanjun; Cho, Hyo-Min; Barber, William C.; Iwanczyk, Jan S.; Molloi, Sabee

2014-01-01

Purpose: To investigate the feasibility of characterizing a Si strip photon-counting detector using x-ray fluorescence. Methods: X-ray fluorescence was generated by using a pencil beam from a tungsten anode x-ray tube with 2 mm Al filtration. Spectra were acquired at 90° from the primary beam direction with an energy-resolved photon-counting detector based on an edge illuminated Si strip detector. The distances from the source to target and the target to detector were approximately 19 and 11 cm, respectively. Four different materials, containing silver (Ag), iodine (I), barium (Ba), and gadolinium (Gd), were placed in small plastic containers with a diameter of approximately 0.7 cm for x-ray fluorescence measurements. Linear regression analysis was performed to derive the gain and offset values for the correlation between the measured fluorescence peak center and the known fluorescence energies. The energy resolutions and charge-sharing fractions were also obtained from analytical fittings of the recorded fluorescence spectra. An analytical model, which employed four parameters that can be determined from the fluorescence calibration, was used to estimate the detector response function. Results: Strong fluorescence signals of all four target materials were recorded with the investigated geometry for the Si strip detector. The average gain and offset of all pixels for detector energy calibration were determined to be 6.95 mV/keV and −66.33 mV, respectively. The detector’s energy resolution remained at approximately 2.7 keV for low energies, and increased slightly at 45 keV. The average charge-sharing fraction was estimated to be 36% within the investigated energy range of 20–45 keV. The simulated detector output based on the proposed response function agreed well with the experimental measurement. Conclusions: The performance of a spectral imaging system using energy-resolved photon-counting detectors is very dependent on the energy calibration of the detector. The proposed x-ray fluorescence technique offers an accurate and efficient way to calibrate the energy response of a photon-counting detector. PMID:25471962

Feasibility study of a ``4H'' X-ray camera based on GaAs:Cr sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dragone, Angelo; Kenney, Chris; Lozinskaya, Anastassiya

Here, we describe a multilayer stacked X-ray camera concept. This type of technology is called `4H' X-ray cameras, where 4H stands for high-Z (Z>30) sensor, high-resolution (less than 300 micron pixel pitch), high-speed (above 100 MHz), and high-energy (above 30 keV in photon energy). The components of the technology, similar to the popular two-dimensional (2D) hybrid pixelated array detectors, consists of GaAs:Cr sensors bonded to high-speed ASICs. 4H cameras based on GaAs also use integration mode of X-ray detection. The number of layers, on the order of ten, is smaller than an earlier configuration for single-photon-counting (SPC) mode of detectionmore » [1]. High-speed ASIC based on modification to the ePix family of ASIC is discussed. Applications in X-ray free electron lasers (XFELs), synchrotrons, medicine and non-destructive testing are possible.« less

Feasibility study of a ``4H'' X-ray camera based on GaAs:Cr sensor

DOE PAGES

Dragone, Angelo; Kenney, Chris; Lozinskaya, Anastassiya; ...

2016-11-29

Here, we describe a multilayer stacked X-ray camera concept. This type of technology is called `4H' X-ray cameras, where 4H stands for high-Z (Z>30) sensor, high-resolution (less than 300 micron pixel pitch), high-speed (above 100 MHz), and high-energy (above 30 keV in photon energy). The components of the technology, similar to the popular two-dimensional (2D) hybrid pixelated array detectors, consists of GaAs:Cr sensors bonded to high-speed ASICs. 4H cameras based on GaAs also use integration mode of X-ray detection. The number of layers, on the order of ten, is smaller than an earlier configuration for single-photon-counting (SPC) mode of detectionmore » [1]. High-speed ASIC based on modification to the ePix family of ASIC is discussed. Applications in X-ray free electron lasers (XFELs), synchrotrons, medicine and non-destructive testing are possible.« less

Preliminary designs for X-ray source modifications for the Marshall Space Flight Center's X-ray calibration facility

NASA Technical Reports Server (NTRS)

Croft, W. L.

1986-01-01

The objective of this investigation is to develop preliminary designs for modifications to the X-ray source of the MSFC X-Ray Calibration Facility. Recommendations are made regarding: (1) the production of an unpolarized X-ray beam, (2) modification of the source to provide characteristic X-rays with energies up to 40 keV, and (3) addition of the capability to calibrate instruments in the extreme ultraviolet wavelength region.

SphinX x-ray spectrophotometer

NASA Astrophysics Data System (ADS)

Kowaliński, Mirosław

2012-05-01

This paper presents assumptions to a PhD thesis. The thesis will be based on the construction of Solar Photometer in X-rays (SphinX). SphinX was an instrument developed to detect the soft X-rays from the Sun. It was flown on board the Russian CORONAS-Photon satellite from January 30, 2009 to the end of November, 2009. During 9 months in orbit SphinX provided an excellent and unique set of observations. It revealed about 750 flares and brightenings. The instrument observed in energy range 1.0 - 15.0 keV with resolution below ~0.5 keV. Here, the SphinX instrument objectives, design, performance and operation principle are described. Below results of mechanical and thermal - vacuum tests necessary to qualify the instrument to use in space environment are presented. Also the calibration results of the instrument are discussed. In particular detail it is described the Electrical Ground Support Equipment (EGSE) for SphinX. The EGSE was used for all tests of the instrument. At the end of the paper results obtained from the instrument during operation in orbit are discussed. These results are compared with the other similar measurements performed from the separate spacecraft instruments. It is suggested design changes in future versions of SphinX.

The X-ray emitting galaxy Centaurus A

NASA Technical Reports Server (NTRS)

Mushotzky, R. F.; Serlemitsos, P. J.; Boldt, E. A.; Holt, S. S.; Becker, R. H.

1978-01-01

OSO-8 X-ray observations of Cen A in 1975 and 1976 are reported. The source spectrum can be well fitted in both years by a power law of number index 1.66 and absorption due to 1.3 by 10 to the 23rd power atoms/sq cm. The total flux varied by a factor of 2 between 1975 and 1976. In 1976 there were flux variations of approximately 40% on a time scale of days. Measurements of the 6.4-keV Fe fluorescent line and the 7.1-keV absorption edge imply Fe/H of approximately 0.000016. Simultaneous radio measurements show variation in phase with X-ray variability. Consideration of radio, millimeter, infrared, and X-ray data shows that all the data can be accounted for by a model in which the X-rays are due to a synchrotron self-Compton source embedded in a cold H2 cloud.

Simulations of Beam Optics and Bremsstrahlung for High Intensity and Brightness Channeling Radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hyun, J.; Piot, P.; Sen, T.

2018-04-12

This paper presents X-ray spectra of channeling radiation expected at the FAST (Fermi Accelerator Science and Technology) facility in Fermilab. Our purpose is to produce high brightness quasi-monochromatic X-rays in an energy range from 40 keV to 110 keV. We will use a diamond crystal and low emittance electrons with an energy of around 43 MeV. The quality of emitted X-rays depends on parameters of the electron beam at the crystal. We present simulations of the beam optics for high brightness and high yield operations for a range of bunch charges. We estimate the X-ray spectra including bremsstrahlung background. Wemore » discuss how the electron beam distributions after the diamond crystal are affected by channeling. We discuss an X-ray detector system to avoid pile-up effects during high charge operations.« less

Simulations of Beam Optics and Bremsstrahlung for High Intensity and Brightness Channeling Radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hyun, J.; Piot, P.; Sen, T.

This paper presents X-ray spectra of channeling radiation expected at the FAST (Fermi Accelerator Science and Technology) facility in Fermilab. Our purpose is to produce high brightness quasi-monochromatic X-rays in an energy range from 40 keV to 110 keV. We will use a diamond crystal and low emittance electrons with an energy of around 43 MeV. The quality of emitted X-rays depends on parameters of the electron beam at the crystal. We present simulations of the beam optics for high brightness and high yield operations for a range of bunch charges. We estimate the X-ray spectra including bremsstrahlung background. Wemore » discuss how the electron beam distributions after the diamond crystal are affected by channeling. Here, we discuss an X-ray detector system to avoid pile-up effects during high charge operations.« less

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

PubMed

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.

Simulations of Beam Optics and Bremsstrahlung for High Intensity and Brightness Channeling Radiation

DOE PAGES

Hyun, J.; Piot, P.; Sen, T.

2018-06-14

This paper presents X-ray spectra of channeling radiation expected at the FAST (Fermi Accelerator Science and Technology) facility in Fermilab. Our purpose is to produce high brightness quasi-monochromatic X-rays in an energy range from 40 keV to 110 keV. We will use a diamond crystal and low emittance electrons with an energy of around 43 MeV. The quality of emitted X-rays depends on parameters of the electron beam at the crystal. We present simulations of the beam optics for high brightness and high yield operations for a range of bunch charges. We estimate the X-ray spectra including bremsstrahlung background. Wemore » discuss how the electron beam distributions after the diamond crystal are affected by channeling. Here, we discuss an X-ray detector system to avoid pile-up effects during high charge operations.« less

High-energy (>70 keV) x-ray conversion efficiency measurement on the ARC laser at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Chen, Hui; Hermann, M. R.; Kalantar, D. H.; Martinez, D. A.; Di Nicola, P.; Tommasini, R.; Landen, O. L.; Alessi, D.; Bowers, M.; Browning, D.; Brunton, G.; Budge, T.; Crane, J.; Di Nicola, J.-M.; Döppner, T.; Dixit, S.; Erbert, G.; Fishler, B.; Halpin, J.; Hamamoto, M.; Heebner, J.; Hernandez, V. J.; Hohenberger, M.; Homoelle, D.; Honig, J.; Hsing, W.; Izumi, N.; Khan, S.; LaFortune, K.; Lawson, J.; Nagel, S. R.; Negres, R. A.; Novikova, L.; Orth, C.; Pelz, L.; Prantil, M.; Rushford, M.; Shaw, M.; Sherlock, M.; Sigurdsson, R.; Wegner, P.; Widmayer, C.; Williams, G. J.; Williams, W.; Whitman, P.; Yang, S.

2017-03-01

The Advanced Radiographic Capability (ARC) laser system at the National Ignition Facility (NIF) is designed to ultimately provide eight beamlets with a pulse duration adjustable from 1 to 30 ps, and energies up to 1.5 kJ per beamlet. Currently, four beamlets have been commissioned. In the first set of 6 commissioning target experiments, the individual beamlets were fired onto gold foil targets with energy up to 1 kJ per beamlet at 20-30 ps pulse length. The x-ray energy distribution and pulse duration were measured, yielding energy conversion efficiencies of 4-9 × 10-4 for x-rays with energies greater than 70 keV. With greater than 3 J of such x-rays, ARC provides a high-precision x-ray backlighting capability for upcoming inertial confinement fusion and high-energy-density physics experiments on NIF.

Effect of shape and thickness of asbestos bundles and fibres on EDS microanalysis: A Monte Carlo simulation

NASA Astrophysics Data System (ADS)

Moro, D.; Valdre, G.

2016-02-01

Quantitative microanalysis of tiny asbestos mineral fibres by scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM-EDS) still represents a complex analytical issue. This complexity arises from the variable fibre shape and small thickness (< 5 μm) compared with the penetration of the incident electron beam. Here, we present the results of Monte Carlo simulations of chrysotile, crocidolite and amosite fibres (and bundles of fibres) of circular and square section and thicknesses from 0.1 μm to 10 μm, to investigate the effect of shape and thickness on SEM-EDS microanalysis. The influence of shape and thickness on the simulated spectrum was investigated for electron beam energies of 5, 15 and 25 keV, respectively. A strong influence of the asbestos bundles and fibres shape and thickness on the detected EDS X-ray intensity was observed. The X-ray intensity trends as a function of fibre thickness showed a non-linear dependence for all the elements and minerals. In general, the X-ray intensities showed a considerable reduction for thicknesses below about 5 μm at 5 keV, 2 μm at 15 keV, and 5 μm at 25 keV. Correction parameters, k-ratios, for the asbestos fibre thickness effect, are reported.

Energy-discrimination X-ray computed tomography system utilizing a silicon-PIN detector and its application to 2.0-keV-width K-edge imaging

NASA Astrophysics Data System (ADS)

Hagiwara, Osahiko; Watanabe, Manabu; Sato, Eiichi; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Nagao, Jiro; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-05-01

Demonstration of narrow-energy-width computed tomography (CT) was carried out by means of energy-discrimination. An X-ray CT system is of a first-generation type and consists of an X-ray generator, a turntable, a translation stage, a two-stage controller, a silicon-PIN detector system with amplifiers, a multi-channel analyzer (MCA), a counter card (CC), and a personal computer (PC). CT is accomplished by repeating the translation and the rotation of an object, and projection curves of the object are obtained by the translation of the moving object. Both photon-energy level and energy width are determined by the MCA, and the pulses of the discriminated event signal from the MCA are counted by CC in conjunction with PC. The maximum count rate was approximately 300 cps (counts per second) with energy widths of 2.0 keV, and energy-discrimination CT was carried out with a photon-energy resolution of 0.15 keV. To perform iodine K-edge CT, X-ray photons with an energy range from 33.2 to 35.2 keV were used. Next, to carry out cerium K-edge CT, an energy range from 40.3 to 42.3 keV was selected.

Status and expected perfomance of the MAXI mission for the JEM/ISS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kataoka, J.; Kawai, N.

2008-12-24

MAXI (Monitor of All-sky X-ray Image) is the first payload to be attached on JEM-EF (Kibo exposed facility) of ISS. It provides an all sky X-ray image every ISS orbit. Only with a few weeks scan, MAXI is expected to make a milli-Crab X-ray all sky map excluding bright region around the sun. Thus, MAXI does not only inform X-ray novae and transients rapidly to world astronomers if once they occur, but also observes long-term variability of Galact ic and extra-Galactic X-ray sources. MAXI also provides an X-ray source catalogue at that time with diffuse cosmic X-ray background. MAXI consistsmore » of two kinds of detectors, position sensitive gas-proportional counters for 2-30 keV X-rays and CCD cameras for 0.5-10 keV X-rays. All instruments of MAXI are now in final phase of pre-launching tests of their flight modules. We are also carrying out performance tests for X-ray detectors and collimators. Data processing and analysis software including alert system on ground are being developed by mission team. In this paper we report an overview of final instruments of MAXI and capability of MAXI.« less

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

NASA Technical Reports Server (NTRS)

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

Resonant Compton Upscattering Models of Magnetar Hard X-ray Emission and Polarization

NASA Astrophysics Data System (ADS)

Baring, Matthew G.; Wadiasingh, Zorawar; Gonthier, Peter L.; Kust Harding, Alice

2017-08-01

Non-thermal quiescent X-ray emission extending between 10 keV and around 150 keV has been seen in about 10 magnetars by RXTE, INTEGRAL, Suzaku and Fermi-GBM. For inner magnetospheric models of such hard X-ray signals, resonant Compton upscattering is anticipated to be the most efficient process for generating the continuum radiation. This is because the scattering becomes resonant at the cyclotron frequency, and the effective cross section exceeds the classical Thomson value by over two orders of magnitude. We present angle-dependent hard X-ray upscattering model spectra for uncooled monoenergetic relativistic electrons injected in inner regions of pulsar magnetospheres. These spectra are integrated over closed field lines and obtained for different observing perspectives. The spectral cut-off energies are critically dependent on the observer viewing angles and electron Lorentz factor. We find that electrons with energies less than around 15 MeV will emit most of their radiation below 250 keV, consistent with the observed turnovers in magnetar hard X-ray tails. Moreover, electrons of higher energy still emit most of the radiation below around 1 MeV, except for quasi-equatorial emission locales for select pulses phases. In such cases, attenuation mechanisms such as pair creation will be prolific, thereby making it difficult to observe signals extending into the Fermi-LAT band. Our spectral computations use new state-of-the-art, spin-dependent formalism for the QED Compton scattering cross section in strong magnetic fields. The emission exhibits strong polarization above around 30 keV that is anticipated to be dependent on pulse phase, thereby defining science agendas for future hard X-ray polarimeters.

Spectral and Temporal Characteristics of LS PEG and TW PIC Using XMM-NEWTON Data

NASA Astrophysics Data System (ADS)

Talebpour Sheshvan, Nasrin; Balman, Solen

2016-07-01

We report the analysis of archival XMM-Newton X-ray observations of LS Peg and TW Pic. These are Cataclysmic Variables (CVs) suggested as Intermediate Polars (IPs), but unconfirmed in the X-rays. Identification of several periodic oscillations in the optical band hint them as IPs. Unlike the previous spectral analysis on the EPIC-MOS data by fitting a hot optically thin plasma emission model with a single temperature for LS Peg, we simultaneously fitted all EPIC spectrum (pn+MOS) using a composite model of absorption for interstellar medium (tbabs) with two different partial covering absorbers (pcfabs) including a multitemperature plasma emission component (cevmkl) and a Gaussian emission line at 6.4 keV. TW Pic is best modeled in a similar manner with only one partial covering absorber and an extra Gaussian emission line at 6.7 keV. LS Peg has a maximum plasma temperature of ˜14.8 keV with an X-ray luminosity of ˜5×10^{32}ergs ^{-1} translating to an accretion rate of ˜1.27×10^{-10}M _{⊙}yr ^{-1}. TW Pic shows kT _{max} ˜38.7 keV with an X-ray luminosity around 1.6×10^{33}ergs ^{-1} at an accretion rate of ˜4×10^{-10}M _{⊙}yr ^{-1}. In addition, we discuss orbital modulations in the X-rays and power spectral analysis, and derive the EPIC pn spectra for orbital minimum and orbital maximum phases for both sources. We elaborate on the geometry of accretion and absorption in the X-ray emitting regions of both sources with articulation on the magnetic nature.

The NuSTAR Extragalactic Surveys: The Number Counts of Active Galactic Nuclei and The Resolved Fraction of The Cosmic X-Ray Background

DOE PAGES

Harrison, F. A.; Aird, J.; Civano, F.; ...

2016-11-07

Here, we present the 3–8 keV and 8–24 keV number counts of active galactic nuclei (AGNs) identified in the Nuclear Spectroscopic Telescope Array (NuSTAR) extragalactic surveys. NuSTAR has now resolved 33%–39% of the X-ray background in the 8–24 keV band, directly identifying AGNs with obscuring columns up tomore » $$\\sim {10}^{25}\\,{\\mathrm{cm}}^{-2}$$. In the softer 3–8 keV band the number counts are in general agreement with those measured by XMM-Newton and Chandra over the flux range $$5\\times {10}^{-15}\\,\\lesssim $$ S(3–8 keV)/$$\\mathrm{erg}\\,{{\\rm{s}}}^{-1}\\,{\\mathrm{cm}}^{-2}\\,\\lesssim \\,{10}^{-12}$$ probed by NuSTAR. In the hard 8–24 keV band NuSTAR probes fluxes over the range $$2\\times {10}^{-14}\\,\\lesssim $$ S(8–24 keV)/$$\\mathrm{erg}\\,{{\\rm{s}}}^{-1}\\,{\\mathrm{cm}}^{-2}\\,\\lesssim \\,{10}^{-12}$$, a factor ~100 fainter than previous measurements. The 8–24 keV number counts match predictions from AGN population synthesis models, directly confirming the existence of a population of obscured and/or hard X-ray sources inferred from the shape of the integrated cosmic X-ray background. The measured NuSTAR counts lie significantly above simple extrapolation with a Euclidian slope to low flux of the Swift/BAT 15–55 keV number counts measured at higher fluxes (S(15–55 keV) gsim 10-11 $$\\mathrm{erg}\\,{{\\rm{s}}}^{-1}\\,{\\mathrm{cm}}^{-2}$$), reflecting the evolution of the AGN population between the Swift/BAT local ($$z\\lt 0.1$$) sample and NuSTAR's $$z\\sim 1$$ sample. CXB synthesis models, which account for AGN evolution, lie above the Swift/BAT measurements, suggesting that they do not fully capture the evolution of obscured AGNs at low redshifts.« less

Feasibility of spectro-photometry in X-rays (SPHINX) from the moon

NASA Astrophysics Data System (ADS)

Sarkar, Ritabrata; Chakrabarti, Sandip Kumar

2010-08-01

Doing space Astronomy on lunar surface has several advantages. We present here feasibility of an All Sky Monitoring Payload for Spectro-photometry in X-rays (SPHINX) which can be placed on a lander on the moon or in a space craft orbiting around the moon. The Si-PIN photo-diodes and CdTe crystals are used to detect solar flares, bright gamma bursts, soft gamma-ray repeaters from space and also X-ray fluorescence (XRF) from lunar surface. We present the complete Geant4 simulation to study the feasibility of such an instrument in presence of Cosmic Diffused X-Ray Background (CDXRB). We find that the signal to noise ratio is sufficient for moderate to bright GRBs (above 5 keV), for the quiet sun (up to 100 keV), solar flares, soft gamma-ray repeaters, X-ray Fluorescence (XRF) of lunar surface etc. This is a low-cost system which is capable of performing multiple tasks while stationed at the natural satellite of our planet.

Current developments and tests of small x-ray optical systems for space applications

NASA Astrophysics Data System (ADS)

Pina, L.; Hudec, R.; Inneman, A.; Doubravová, D.; Marsikova, V.

2017-05-01

The paper addresses the X-ray monitoring for astrophysical applications. A novel approach based on the use of 1D and 2D "Lobster eye" optics in combination with Timepix X-ray detector in the energy range 3 - 40 keV was further studied. Wide-field optical system of this type has not been used in space yet. Designed wide-field optical system combined with Timepix X-ray detector is described together with latest experimental results obtained during laboratory tests. Proposed project includes theoretical study and a functional sample of the Timepix X-ray detector with multifoil wide-field X-ray "Lobster eye" optics. Using optics to focus X-rays on a detector is the only solution in cases where intensity of impinging X-ray radiation is below the sensitivity of the detector, e.g. while monitoring astrophysical objects in space, or phenomena in the Earth's atmosphere. The optical system is considered to be used in a student rocket experiment.

X-Ray Detector Research at MSFC for Space Applications

NASA Technical Reports Server (NTRS)

Gaskin, Jessica

2006-01-01

NASA's Vision for Space Exploration has specific goals aimed at exploring the Solar System. This vision, under presidential mandate includes landing humans on the moon before the end of the next decade, paving the way for eventual journeys to Mars and beyond. The first missions to the moon will be in the form of both Orbiters and Landers, with the goal of paving the way for human return. One of the instruments we are currently working on,in collaboration with Brookhaven National Laboratory, is a lunar orbiter fluorescent x-ray spectrometer to finely map the light elements (down to Carbon) on surface of the moon. Funded NASA s Planetary Instrument Definition and Development Program the instrument is based on silicon drift detector arrays read out by custom ASICs. These offer the promise of high spectral resolution, necessary for resolving weak lines against a strong background continuum, and very low power requirements, necessary for large areas (greater than 500 square centimeters) required for future lunar missions. Further, the inherent radiation hardness of these detectors makes them ideal candidates for exploring the Jovian system, where the harsh radiation environment from Jupiter s radiation belts creates unfavorable detector conditions. Looking beyond our solar system, in the hard x-ray regime (20-80keV.), we are studying Cadmium-Zinc-Telluride pixilated detectors as feasible candidates for focal plane detectors of a hard x-ray telescope. This energy region bridges the gap between thermal and non-thermal x-ray emission from astronomical sources, will allow us to better understand supernovae nucleosynthesis (such as through the Ti-44 lines at 68keV and 78keV), Active Galactic Nuclei and other compact objects, more completely. The detectors that we are characterizing are 2mm in thickness and are pixilated with a 16x16 array of 300 micrometer pitch pixels (50micometer gap). These detectors are designed at Rutherford Appleton Laboratory, material is from eV Products, and polymer flip-chip assembly was performed by a commercial vendor. An energy resolution of 2.0% at 60keV (or better) should allow us to sufficiently distinguish lines of interest from background continuum, and the detector spatial resolution should be fine enough to over-sample the focal spot from the x-ray focusing optics by about a factor of two. Full technical details of these developments will be presented.

THCOBRA X-ray imaging detector operating in pure Kr

NASA Astrophysics Data System (ADS)

Carramate, L. F. N. D.; Silva, A. L. M.; Azevedo, C. D. R.; Fortes, I.; Monteiro, S. G.; Sousa, S.; Ribeiro, F. M.; De Francesco, S.; Covita, D. S.; Veloso, J. F. C. A.

2017-05-01

MicroPattern Gaseous Detectors (MPGD) have been explored for X-ray imaging, namely for photon counting imaging which allows the improvement of image quality and the collection of more information than the conventional commercial systems. A 2D-THCOBRA based detector was developed, studied and used to acquire X-ray transmission images. The 2D-THCOBRA structure used has an active area of 2.8 × 2.8 cm2 and allows obtaining the position and energy information of each single photon that interacts with the detector. It is filled with pure Kr at 1 bar operating in a sealed mode. Within this work the performance of the detector is evaluated in terms of charge gain, count rate, time stability, energy and spatial resolutions. The detector presents a charge gain of 2 × 104 and an energy resolution of 23% for 5.9 keV, showing gain stability along time for a count rate of about 1 × 105 Hz/mm2. It presents a spatial resolution of 600 μm (σ = 255 μm) and 500 μm (σ = 213 μm) for x and y directions, respectively, and, considering energy bins about 650 μm (σ = 277 μm) for approximately 16.5 keV. X-ray transmission images of some samples presented here show good prospects for X-ray imaging applications.

A laser-Compton scattering prototype experiment at 100 MeV linac of Shanghai Institute of Applied Physics.

PubMed

Luo, W; Xu, W; Pan, Q Y; Cai, X Z; Chen, J G; Chen, Y Z; Fan, G T; Fan, G W; Guo, W; Li, Y J; Liu, W H; Lin, G Q; Ma, Y G; Shen, W Q; Shi, X C; Xu, B J; Xu, J Q; Xu, Y; Zhang, H O; Yan, Z; Yang, L F; Zhao, M H

2010-01-01

As a prototype of the Shanghai Laser Electron Gamma Source in the Shanghai Synchrotron Radiation Facility, an x-ray source based on laser-Compton scattering (LCS) has been installed at the terminal of the 100 MeV linac of the Shanghai Institute of Applied Physics. LCS x-rays are generated by interactions between Q-switched Nd:yttrium aluminum garnet laser pulses [with wavelength of 1064 nm and pulse width of 21 ns (full width at half maximum)] and electron bunches [with energy of 108 MeV and pulse width of 0.95 ns (rms)] at an angle of 42 degrees between laser and electron beam. In order to measure the energy spectrum of LCS x-rays, a Si(Li) detector along the electron beam line axis is positioned at 9.8 m away from a LCS chamber. After background subtraction, the LCS x-ray spectrum with the peak energy of 29.1+/-4.4|(stat)+/-2.1|(syst) keV and the peak width (rms) of 7.8+/-2.8|(stat)+/-0.4|(syst) keV is observed. Normally the 100 MeV linac operates with the electron macropulse charge of 1.0 nC/pulse, and the electron and laser collision repetition rate of 20 Hz. Therefore, the total LCS x-ray flux of (5.2+/-2.0) x 10(2) Hz can be achieved.

Near- and Extended-Edge X-Ray-Absorption Fine-Structure Spectroscopy Using Ultrafast Coherent High-Order Harmonic Supercontinua

NASA Astrophysics Data System (ADS)

Popmintchev, Dimitar; Galloway, Benjamin R.; Chen, Ming-Chang; Dollar, Franklin; Mancuso, Christopher A.; Hankla, Amelia; Miaja-Avila, Luis; O'Neil, Galen; Shaw, Justin M.; Fan, Guangyu; Ališauskas, Skirmantas; Andriukaitis, Giedrius; Balčiunas, Tadas; Mücke, Oliver D.; Pugzlys, Audrius; Baltuška, Andrius; Kapteyn, Henry C.; Popmintchev, Tenio; Murnane, Margaret M.

2018-03-01

Recent advances in high-order harmonic generation have made it possible to use a tabletop-scale setup to produce spatially and temporally coherent beams of light with bandwidth spanning 12 octaves, from the ultraviolet up to x-ray photon energies >1.6 keV . Here we demonstrate the use of this light for x-ray-absorption spectroscopy at the K - and L -absorption edges of solids at photon energies near 1 keV. We also report x-ray-absorption spectroscopy in the water window spectral region (284-543 eV) using a high flux high-order harmonic generation x-ray supercontinuum with 109 photons/s in 1% bandwidth, 3 orders of magnitude larger than has previously been possible using tabletop sources. Since this x-ray radiation emerges as a single attosecond-to-femtosecond pulse with peak brightness exceeding 1026 photons/s /mrad2/mm2/1 % bandwidth, these novel coherent x-ray sources are ideal for probing the fastest molecular and materials processes on femtosecond-to-attosecond time scales and picometer length scales.

The Linac Coherent Light Source: Recent Developments and Future Plans

DOE PAGES

Schoenlein, R. W.; Boutet, S.; Minitti, M. P.; ...

2017-08-18

The development of X-ray free-electron lasers (XFELs) has launched a new era in X-ray science by providing ultrafast coherent X-ray pulses with a peak brightness that is approximately one billion times higher than previous X-ray sources. The Linac Coherent Light Source (LCLS) facility at the SLAC National Accelerator Laboratory, the world’s first hard X-ray FEL, has already demonstrated a tremendous scientific impact across broad areas of science. Here in this paper, a few of the more recent representative highlights from LCLS are presented in the areas of atomic, molecular, and optical science; chemistry; condensed matter physics; matter in extreme conditions;more » and biology. This paper also outlines the near term upgrade (LCLS-II) and motivating science opportunities for ultrafast X-rays in the 0.25–5 keV range at repetition rates up to 1 MHz. Future plans to extend the X-ray energy reach to beyond 13 keV (<1 Å) at high repetition rate (LCLS-II-HE) are envisioned, motivated by compelling new science of structural dynamics at the atomic scale.« less

X-ray Emission Characteristics of Ultra-High Energy Density Relativistic Plasmas Created by Ultrafast Laser Irradiation of Nanowire Arrays

NASA Astrophysics Data System (ADS)

Hollinger, R. C.; Bargsten, C.; Shlyaptsev, V. N.; Pukhov, A.; Purvis, M. A.; Townsend, A.; Keiss, D.; Wang, Y.; Wang, S.; Prieto, A.; Rocca, J. J.

2014-10-01

Irradiation of ordered nanowire arrays with high contrast femtosecond laser pulses of relativistic intensity creates volumetrically heated near solid density plasmas characterized by multi-KeV temperatures and extreme degrees of ionization. The large hydrodynamic-to-radiative lifetime ratio of these plasmas results in very efficient X-ray generation. Au nanowire array plasmas irradiated at I 5×1018 Wcm-2 are measured to convert ~ 5 percent of the laser energy into h ν > 0.9 KeV X-rays, and >1 × 10-4 into h ν > 9 KeV photons, creating bright picosecond X-ray sources. The angular distribution of the higher energy photons is measured to change from isotropic into annular as the intensity increases, while softer X-ray emission (h ν >1 KeV) remains isotropic and nearly unchanged. Model simulations suggest the unexpected annular distribution of the hard X-rays might result from bremsstrahlung of fast electrons confined in a high aspect ratio near solid density plasma in which the electron-ion collision mean free-path is of the order of the plasma thickness. Work supported by the U.S Department of Energy, Fusion Energy Sciences and the Defense Threat Reduction Agency Grant HDTRA-1-10-1-0079. A.P was supported by of DFG-funded project TR18.

SPECTRAL SURVEY OF X-RAY BRIGHT ACTIVE GALACTIC NUCLEI FROM THE ROSSI X-RAY TIMING EXPLORER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rivers, Elizabeth; Markowitz, Alex; Rothschild, Richard, E-mail: erivers@ucsd.edu

2011-03-15

Using long-term monitoring data from the Rossi X-ray Timing Explorer (RXTE), we have selected 23 active galactic nuclei (AGNs) with sufficient brightness and overall observation time to derive broadband X-ray spectra from 3 to {approx}>100 keV. Our sample includes mainly radio-quiet Seyferts, as well as seven radio-loud sources. Given the longevity of the RXTE mission, the greater part of our data is spread out over more than a decade, providing truly long-term average spectra and eliminating inconsistencies arising from variability. We present long-term average values of absorption, Fe line parameters, Compton reflection strengths, and photon indices, as well as fluxesmore » and luminosities for the hard and very hard energy bands, 2-10 keV and 20-100 keV, respectively. We find tentative evidence for high-energy rollovers in three of our objects. We improve upon previous surveys of the very hard X-ray energy band in terms of accuracy and sensitivity, particularly with respect to confirming and quantifying the Compton reflection component. This survey is meant to provide a baseline for future analysis with respect to the long-term averages for these sources and to cement the legacy of RXTE, and especially its High Energy X-ray Timing Experiment, as a contributor to AGN spectral science.« less

The Cambridge-Cambridge X-ray Serendipity Survey: I X-ray luminous galaxies

NASA Technical Reports Server (NTRS)

Boyle, B. J.; Mcmahon, R. G.; Wilkes, B. J.; Elvis, M.

1994-01-01

We report on the first results obtained from a new optical identification program of 123 faint X-ray sources with S(0.5-2 keV) greater than 2 x 10(exp -14) erg/s/sq cm serendipitously detected in ROSAT PSPC pointed observations. We have spectroscopically identified the optical counterparts to more than 100 sources in this survey. Although the majority of the sample (68 objects) are QSO's, we have also identified 12 narrow emission line galaxies which have extreme X-ray luminosities (10(exp 42) less than L(sub X) less than 10(exp 43.5) erg/s). Subsequent spectroscopy reveals them to be a mixture of star-burst galaxies and Seyfert 2 galaxies in approximately equal numbers. Combined with potentially similar objects identified in the Einstein Extended Medium Sensitivity Survey, these X-ray luminous galaxies exhibit a rate of cosmological evolution, L(sub X) varies as (1 + z)(exp 2.5 +/- 1.0), consistent with that derived for X-ray QSO's. This evolution, coupled with the steep slope determined for the faint end of the X-ray luminosity function (Phi(L(sub X)) varies as L(sub X)(exp -1.9)), implies that such objects could comprise 15-35% of the soft (1-2 keV) X-ray background.

Performance verification of the Gravity and Extreme Magnetism Small explorer (GEMS) x-ray polarimeter

NASA Astrophysics Data System (ADS)

Enoto, Teruaki; Black, J. Kevin; Kitaguchi, Takao; Hayato, Asami; Hill, Joanne E.; Jahoda, Keith; Tamagawa, Toru; Kaneko, Kenta; Takeuchi, Yoko; Yoshikawa, Akifumi; Marlowe, Hannah; Griffiths, Scott; Kaaret, Philip E.; Kenward, David; Khalid, Syed

2014-07-01

Polarimetry is a powerful tool for astrophysical observations that has yet to be exploited in the X-ray band. For satellite-borne and sounding rocket experiments, we have developed a photoelectric gas polarimeter to measure X-ray polarization in the 2-10 keV range utilizing a time projection chamber (TPC) and advanced micro-pattern gas electron multiplier (GEM) techniques. We carried out performance verification of a flight equivalent unit (1/4 model) which was planned to be launched on the NASA Gravity and Extreme Magnetism Small Explorer (GEMS) satellite. The test was performed at Brookhaven National Laboratory, National Synchrotron Light Source (NSLS) facility in April 2013. The polarimeter was irradiated with linearly-polarized monochromatic X-rays between 2.3 and 10.0 keV and scanned with a collimated beam at 5 different detector positions. After a systematic investigation of the detector response, a modulation factor >=35% above 4 keV was obtained with the expected polarization angle. At energies below 4 keV where the photoelectron track becomes short, diffusion in the region between the GEM and readout strips leaves an asymmetric photoelectron image. A correction method retrieves an expected modulation angle, and the expected modulation factor, ~20% at 2.7 keV. Folding the measured values of modulation through an instrument model gives sensitivity, parameterized by minimum detectable polarization (MDP), nearly identical to that assumed at the preliminary design review (PDR).

Conception and realization of a parallel-plate free-air ionization chamber for the absolute dosimetry of an ultrasoft X-ray beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Groetz, J.-E., E-mail: jegroetz@univ-fcomte.fr; Mavon, C.; Fromm, M.

2014-08-15

We report the design of a millimeter-sized parallel plate free-air ionization chamber (IC) aimed at determining the absolute air kerma rate of an ultra-soft X-ray beam (E = 1.5 keV). The size of the IC was determined so that the measurement volume satisfies the condition of charged-particle equilibrium. The correction factors necessary to properly measure the absolute kerma using the IC have been established. Particular attention was given to the determination of the effective mean energy for the 1.5 keV photons using the PENELOPE code. Other correction factors were determined by means of computer simulation (COMSOL™and FLUKA). Measurements of airmore » kerma rates under specific operating parameters of the lab-bench X-ray source have been performed at various distances from that source and compared to Monte Carlo calculations. We show that the developed ionization chamber makes it possible to determine accurate photon fluence rates in routine work and will constitute substantial time-savings for future radiobiological experiments based on the use of ultra-soft X-rays.« less

Galactic Sources Detected in the NuSTAR Serendipitous Survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tomsick, John A.; Clavel, Maïca; Chiu, Jeng-Lun

The Nuclear Spectroscopic Telescope Array (NuSTAR) provides an improvement in sensitivity at energies above 10 keV by two orders of magnitude over non-focusing satellites, making it possible to probe deeper into the Galaxy and universe. Lansbury and collaborators recently completed a catalog of 497 sources serendipitously detected in the 3–24 keV band using 13 deg{sup 2} of NuSTAR coverage. Here, we report on an optical and X-ray study of 16 Galactic sources in the catalog. We identify 8 of them as stars (but some or all could have binary companions), and use information from Gaia to report distances and X-ray luminositiesmore » for 3 of them. There are 4 CVs or CV candidates, and we argue that NuSTAR J233426–2343.9 is a relatively strong CV candidate based partly on an X-ray spectrum from XMM-Newton . NuSTAR J092418–3142.2, which is the brightest serendipitous source in the Lansbury catalog, and NuSTAR J073959–3147.8 are low-mass X-ray binary candidates, but it is also possible that these 2 sources are CVs. One of the sources is a known high-mass X-ray binary (HMXB), and NuSTAR J105008–5958.8 is a new HMXB candidate that has strong Balmer emission lines in its optical spectrum and a hard X-ray spectrum. We discuss the implications of finding these HMXBs for the surface density (log N –log S ) and luminosity function of Galactic HMXBs. We conclude that with the large fraction of unclassified sources in the Galactic plane detected by NuSTAR in the 8–24 keV band, there could be a significant population of low-luminosity HMXBs.« less

Distance and spectrum of the Apollo gamma-ray burst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilman, D.; Metzger, A.E.; Parker, R.H.

1980-03-15

The ..gamma..-ray spectrometer on Apollo 16 obtained spectral information with good energy resolution from more than 2500 burst photons in the energy range 0.06--5.16 MeV. The spectrum from 2 keV to 2 MeV, observed at X-ray energies by the Apollo X-ray spectrometer, is fitted by a thermal bremsstrahlung spectrum with kT=500 keV. The success of the fit implies that the source is optically thin, and it follows that it must be closer than 50 pc. Absence of spectral variability suggests that the burst results from isothermal changes in emission measure.

Optical identification of X-ray source 1RXS J180431.1-273932 as a magnetic cataclysmic variable

NASA Astrophysics Data System (ADS)

Masetti, N.; Nucita, A. A.; Parisi, P.

2012-08-01

The X-ray source 1RXS J180431.1-273932 has been proposed as a new member of the symbiotic X-ray binary (SyXB) class of systems, which are composed of a late-type giant that loses matter to an extremely compact object, most likely a neutron star. In this paper, we present an optical campaign of imaging plus spectroscopy on selected candidate counterparts of this object. We also reanalyzed the available archival X-ray data collected with XMM-Newton. We find that the brightest optical source inside the 90% X-ray positional error circle is spectroscopically identified as a magnetic cataclysmic variable (CV), most likely of intermediate polar type, through the detection of prominent Balmer, He i, He ii, and Bowen blend emissions. On either spectroscopic or statistical grounds, we discard as counterparts of the X-ray source the other optical objects in the XMM-Newton error circle. A red giant star of spectral type M5 III is found lying just outside the X-ray position: we consider this latter object as a fore-/background one and likewise rule it out as a counterpart of 1RXS J180431.1-273932. The description of the X-ray spectrum of the source using a bremsstrahlung plus black-body model gives temperatures of kTbr ~ 40 keV and kTbb ~ 0.1 keV for these two components. We estimate a distance of d ~ 450 pc and a 0.2-10 keV X-ray luminosity of LX ~ 1.7 × 1032 erg s-1 for this system and, using the information obtained from the X-ray spectral analysis, a mass MWD ~ 0.8 M⊙ for the accreting white dwarf (WD). We also confirm an X-ray periodicity of 494 s for this source, which we interpret as the spin period of the WD. In summary, 1RXS J180431.1-273932 is identified as a magnetic CV and its SyXB nature is excluded. Partly based on observations collected at the Italian Telescopio Nazionale Galileo, located at the Observatorio del Roque de los Muchachos (Canary Islands, Spain).Reduced data used for imaging and spectra is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/544/A114

Structure determination from XAFS using high-accuracy measurements of x-ray mass attenuation coefficients of silver, 11 keV-28 keV, and development of an all-energies approach to local dynamical analysis of bond length, revealing variation of effective thermal contributions across the XAFS spectrum.

PubMed

Tantau, L J; Chantler, C T; Bourke, J D; Islam, M T; Payne, A T; Rae, N A; Tran, C Q

2015-07-08

We use the x-ray extended range technique (XERT) to experimentally determine the mass attenuation coefficient of silver in the x-ray energy range 11 kev-28 kev including the silver K absorption edge. The results are accurate to better than 0.1%, permitting critical tests of atomic and solid state theory. This is one of the most accurate demonstrations of cross-platform accuracy in synchrotron studies thus far. We derive the mass absorption coefficients and the imaginary component of the form factor over this range. We apply conventional XAFS analytic techniques, extended to include error propagation and uncertainty, yielding bond lengths accurate to approximately 0.24% and thermal Debye-Waller parameters accurate to 30%. We then introduce the FDMX technique for accurate analysis of such data across the full XAFS spectrum, built on full-potential theory, yielding a bond length accuracy of order 0.1% and the demonstration that a single Debye parameter is inadequate and inconsistent across the XAFS range. Two effective Debye-Waller parameters are determined: a high-energy value based on the highly-correlated motion of bonded atoms (σ(DW) = 0.1413(21) Å), and an uncorrelated bulk value (σ(DW) = 0.1766(9) Å) in good agreement with that derived from (room-temperature) crystallography.

Soft X-ray Emission from Large-Scale Galactic Outflows in Seyfert Galaxies

NASA Astrophysics Data System (ADS)

Colbert, E. J. M.; Baum, S.; O'Dea, C.; Veilleux, S.

1998-01-01

Kiloparsec-scale soft X-ray nebulae extend along the galaxy minor axes in several Seyfert galaxies, including NGC 2992, NGC 4388 and NGC 5506. In these three galaxies, the extended X-ray emission observed in ROSAT HRI images has 0.2-2.4 keV X-ray luminosities of 0.4-3.5 x 10(40) erg s(-1) . The X-ray nebulae are roughly co-spatial with the large-scale radio emission, suggesting that both are produced by large-scale galactic outflows. Assuming pressure balance between the radio and X-ray plasmas, the X-ray filling factor is >~ 10(4) times as large as the radio plasma filling factor, suggesting that large-scale outflows in Seyfert galaxies are predominantly winds of thermal X-ray emitting gas. We favor an interpretation in which large-scale outflows originate as AGN-driven jets that entrain and heat gas on kpc scales as they make their way out of the galaxy. AGN- and starburst-driven winds are also possible explanations if the winds are oriented along the rotation axis of the galaxy disk. Since large-scale outflows are present in at least 50 percent of Seyfert galaxies, the soft X-ray emission from the outflowing gas may, in many cases, explain the ``soft excess" X-ray feature observed below 2 keV in X-ray spectra of many Seyfert 2 galaxies.

Consequences of narrow cyclotron emission from Hercules X-1

NASA Technical Reports Server (NTRS)

Weaver, R. P.

1978-01-01

The implications of the recent observations of a narrow cyclotron line in the hard X-ray spectrum of Hercules X-1 are studied. A Monte Carlo code is used to simulate the X-ray transfer of an intrinsically narrow feature at approximately 56 keV through an opaque, cold magnetospheric shell. The results of this study indicate that if a narrow line can be emitted by the source region, then only about 10% of the photons remain in a narrow feature after scattering through the shell. The remaining photons are scattered into a broad feature (FWHM approximately 30 keV) that peaks near 20 keV. Thus, these calculations indicate that the intrinsic source luminosity of the cyclotron line is at least an order of magnitude greater than the observed luminosity.

Two types of electron events in solar flares

NASA Technical Reports Server (NTRS)

Daibog, E. I.; Kurt, V. G.; Logachev, Y. I.; Stolpovsky, V. G.

1985-01-01

The fluxes and spectra of the flare electrons measured on board Venera-I3 and I4 space probes are compared with the parameters of the hard (E sub x approximately 55 keV) and thermal X-ray bursts. The electron flux amplitude has been found to correlate with flare importance in the thermal X-ray range (r approximately 0.8). The following two types of flare events have been found in the electron component of SCR. The electron flux increase is accompanied by a hard X-ray burst and the electron spectrum index in the approximately 25 to 200 keV energy range is gamma approximately 2 to 3. The electron flux increase is not accompanied by a hard X-ray burst and the electron spectrum is softer (Delta gamma approximately 0.7 to 1.0).

The Orbital Parameters and Nature of the X-ray Pulsar IGR J16393-4643 Using Pulse Timing Analysis

NASA Astrophysics Data System (ADS)

Pearlman, Aaron B.; Corbet, R. H. D.; Pottschmidt, K.; Skinner, G. K.

2011-09-01

A 3.7 day orbital period was previously suggested for the 910 s X-ray pulsar IGR J16393-4643 from a pulse timing study of widely separated X-ray observations (Thompson et al., 2006), placing the system in the supergiant wind-fed region of the Ppulse-Porb diagram. However, orbital periods of 50.2 and 8.1 days could not be excluded. Nespoli et al. (2010) refute this wind-accreting high-mass X-ray binary classification and suggest a symbiotic X-ray binary (SyXB) designation based on infrared spectroscopy of the proposed counterpart and the potential 50.2 day orbital solution. SyXBs are low-mass X-ray binaries in which a neutron star accretes from the inhomogeneous medium around an M-type giant companion. We find that two statistically independent light curves of IGR J16393-4643, from the Swift Burst Alert Telescope (15-50 keV) and the Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) Galactic bulge scans (2-10 keV), show highly significant orbital modulation near 4.24 days. Making use of this precise orbital period, we present the results from pulse arrival time analysis on IGR J16393-4643 using RXTE PCA observations. We provide significantly improved phase-connected pulse timing results using archival observations presented in Thompson et al. (2006) and additional pulse timing data not included in their study to determine the orbital parameters of the system. The derived 7.5 M⊙ mass function is inconsistent with a SyXB identification.

X-Rays from Galaxies Teeming with Black Holes and Neutron Stars

NASA Technical Reports Server (NTRS)

Hornschemeier, Ann

2010-01-01

Thanks to more than forty years of investment in space-based technology capable of observing the Universe in the x-ray band (0.5 - 100 keV), we have learned quite a bit about the X-ray universe. It has become clear that most of the glow of the X-ray sky is attributed to accretion onto supermassive black holes. However, as we push ever fainter in our detection methods, we find an interesting population of very faint sources arising. These are normal "Milky-way-type" galaxies that also glow in X-rays. The X-ray emission from these galaxies arises from populations of accreting black holes and neutron stars contained in binary systems. This talk will describe our understanding of this population, including some strange regularity in the production of such accreting binary systems. The future, including new technology planned for the next 5-10 years and anticipated theoretical advancements, will also be discussed.

CARNAÚBA: The Coherent X-Ray Nanoprobe Beamline for the Brazilian Synchrotron SIRIUS/LNLS

NASA Astrophysics Data System (ADS)

Tolentino, Hélio C. N.; Soares, Márcio M.; Perez, Carlos A.; Vicentin, Flávio C.; Abdala, Dalton B.; Galante, Douglas; Teixeira, Verônica de C.; de Araújo, Douglas H. C.; Westfahl, Harry, Jr.

2017-06-01

The CARNAÚBA beamline is the tender-to-hard X-ray (2 - 15 keV) scanning nanoprobe planned for the 4th generation storage ring SIRIUS at the LNLS. CARNAÚBA uses an undulator source with vertical linear polarization in a low-beta straight section and grazing incidence-focusing mirrors to create a nanoprobe at 143 m from the source. The beamline optic is based on KB mirrors and provides high brilliance at an achromatic focal spot down to the diffraction limit diameter of ˜30 nm with a working distance of ˜6 cm. These characteristics are crucial for studying nanometric samples in experiments involving complex stages and environments. The CARNAÚBA beamline aims to perform raster scans using x-ray fluorescence, x-ray absorption spectroscopy, x-ray diffraction and coherent x-ray imaging techniques. Computed tomography will extend these methods to three dimensions.

The X-Ray Light Curve of the Very Luminous Supernova SN 1978K in NGC 1313

NASA Astrophysics Data System (ADS)

Schlegel, Eric M.; Petre, R.; Colbert, E. J. M.

1996-01-01

We present the 0.5-2.0 keV light curve of the X-ray luminous supernova SN 1978K in NGC 1313, based on six ROSAT observations spanning 1990 July to t994 July. SN 1978K is one of a few supernovae or supernova remnants that are very luminous (˜1039-1040 ergs s-1) in the X-ray, optical, and radio bands, and the first, at a supernova age of 10-20 yr, for which sufficient data exist to create an X-ray light curve. The X-ray flux is approximately constant over the 4 yr sampled by our observations, which were obtained 12-16 yr after the initial explosion. Three models exist to explain the large X-ray luminosity: pulsar input, a reverse shock running back into the expanding debris of the supernova, and the outgoing shock crushing of cloudlets in the debris field. Based upon calculations of Chevalier & Fransson, a pulsar cannot provide sufficient energy to produce the soft X-ray luminosity. Based upon the models and the light curve to date, it is not possible to discern the evolutionary phase of the supernova.

M sub-shell X-ray fluorescence cross-section measurements for six elements in the range Z = 78-92 at tuned synchrotron photon energies 5, 7 and 9 keV.

NASA Astrophysics Data System (ADS)

Bansal, Himani; Tiwari, M. K.; Mittal, Raj

2018-01-01

M sub-shell X-ray fluorescence cross-sections of elements Pt, Au, Hg, Pb, Th and U have been measured with linearly polarized photon beams from Indus-II synchrotron source at Raja Ramanna Centre for Advanced Technology (RRCAT), India at tuned 5, 7 and 9 keV energies less than the L3 edge energy of elements. Measurements at present energies and elements are not available in literature. Therefore, measured cross-sections for Mξ, Mδ, Mα, Mβ, Mγ, Mm1 and Mm2 group of X-rays were compared with calculated theoretical values based upon Non Relativistic Hartree-Slater (NRHS) and relativistic Dirac-Fork (DF) and Dirac-Hartree-Slater (DHS) models. The measured cross-sections along with our earlier quoted measurements at 8 and 10 keV by Kaur et al. [Nucl. Instrum. Meth. B, 2014; 320: 37] are found in good agreement with DF and DHS values around 20% deviations and are highly deviated from NRHS values. Most of the spots of observed high deviations in measured and theoretical cross-sections are found to coincide with the presence of crisscrosses/sharp variations in contributing physical parameters photo-ionization cross-sections σMi's and Coster-Kronig yields fij's with Zs.

Development of a compact radiation-hardened low-noise front-end readout ASIC for CZT-based hard X-ray imager

NASA Astrophysics Data System (ADS)

Gao, W.; Gan, B.; Li, X.; Wei, T.; Gao, D.; Hu, Y.

2015-04-01

In this paper, we present the development and performances of a radiation-hardened front-end readout application-specific integrated circuit (ASIC) dedicated to CZT detectors for a hard X-ray imager in space applications. The readout channel consists of a charge sensitive amplifier (CSA), a CR-RC shaper, a fast shaper, a discriminator and a driving buffer. With the additional digital filtering, the readout channel can achieve very low noise performances and low power dissipation. An eight-channel prototype ASIC is designed and fabricated in 0.35 μm CMOS process. The energy range of the detected X-rays is evaluated as 1.45 keV to 281 keV. The gain is larger than 100 mV/fC. The equivalent noise charge (ENC) of the ASIC is 53 e- at zero farad plus 10 e- per picofarad. The power dissipation is less than 4.4 mW/channel. Through the measurement with a CZT detector, the energy resolution is less than 3.45 keV (FWHM) under the irradiation of the radioactive source 241Am. The radiation effect experiments indicate that the proposed ASIC can resist the total ionization dose (TID) irradiation of higher than 200 krad (Si).

The BAT AGN Spectroscopic Survey (BASS)

NASA Astrophysics Data System (ADS)

Koss, Michael

2017-08-01

We present the Swift BAT AGN Spectroscopic Survey (BASS) and discus the first four papers. The catalog represents an unprecedented census of hard-X-ray selected AGN in the local universe, with ~90% of sources at z<0.2. Starting from an all-sky catalog of AGN detected based on their 14-195 keV flux from the 70-month Swift/BAT catalog, we analyze a total of 1279 optical spectra, taken from twelve different telescopes, for a total of 642 spectra of unique AGN. We present the absorption and emission line measurements as well as black hole masses and accretion rates for the majority of obscured and un-obscured AGN (473), representing more than a factor of 10 increase from past studies. Consistent with previous surveys, we find an increase in the fraction of un-obscured (type 1) AGN, as measured from broad Hbeta and Halpha, with increasing 14-195 keV and 2-10 keV luminosity. We find the FWHM of the emission lines to show broad agreement with the X-ray obscuration measurements. Compared to narrow line AGN in the SDSS, the X-ray selected AGN in our sample with emission lines have a larger fraction of dustier galaxies suggesting these types of galaxies are missed in optical AGN surveys using emission line diagnostics.

Measurement of the effective energy of pulsed X-rays emitted from a Mather-type plasma focus device.

PubMed

Miremad, Seyed Milad; Shirani Bidabadi, Babak

2017-07-01

The current study examined the effective energy of pulsed x-rays emitted from a Mather-type plasma focus device with copper anodes at an energy range of 2-3kJ using x-ray transmission radiography. Aluminum filters of different thicknesses and dental x-ray film were used. When air gas was used at a constant voltage of 21kV at 0.3, 0.6, 0.9 and 1.2 mbar, the effective energy of pulsed the x-ray was 10.9, 10.7, 17.3 and 15.8keV, respectively. At 0.6 mbar of air, as the operating voltage increased to 19, 21 and 23kV, the effective energy of the x-ray radiation was 10.6, 10.7 and 12.4keV, respectively. Comprehensive investigation of the characteristics of x-ray emission from plasma focus devices makes it feasible to use this device as an intensive x-ray generator for medical and industrial purposes. The present study is a part of a program which is planned to realize these applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

DEEP CHANDRA X-RAY IMAGING OF A NEARBY RADIO GALAXY 4C+29.30: X-RAY/RADIO CONNECTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siemiginowska, Aneta; Aldcroft, Thomas L.; Burke, D. J.

2012-05-10

We report results from our deep Chandra X-ray observations of a nearby radio galaxy, 4C+29.30 (z = 0.0647). The Chandra image resolves structures on sub-arcsec to arcsec scales, revealing complex X-ray morphology and detecting the main radio features: the nucleus, a jet, hotspots, and lobes. The nucleus is absorbed (N{sub H} {approx_equal} 3.95{sup +0.27}{sub -0.33} Multiplication-Sign 10{sup 23} cm{sup -2}) with an unabsorbed luminosity of L{sub 2-10keV} {approx_equal} (5.08 {+-} 0.52) Multiplication-Sign 10{sup 43} erg s{sup -1} characteristic of Type 2 active galactic nuclei. Regions of soft (<2 keV) X-ray emission that trace the hot interstellar medium (ISM) are correlatedmore » with radio structures along the main radio axis, indicating a strong relation between the two. The X-ray emission extends beyond the radio source and correlates with the morphology of optical-line-emitting regions. We measured the ISM temperature in several regions across the galaxy to be kT {approx_equal} 0.5 keV, with slightly higher temperatures (of a few keV) in the center and in the vicinity of the radio hotspots. Assuming that these regions were heated by weak shocks driven by the expanding radio source, we estimated the corresponding Mach number of 1.6 in the southern regions. The thermal pressure of the X-ray-emitting gas in the outermost regions suggests that the hot ISM is slightly underpressured with respect to the cold optical-line-emitting gas and radio-emitting plasma, which both seem to be in a rough pressure equilibrium. We conclude that 4C+29.30 displays a complex view of interactions between the jet-driven radio outflow and host galaxy environment, signaling feedback processes closely associated with the central active nucleus.« less

Combined FDTD-Monte Carlo analysis and a novel design for ZnO scintillator rods in polycarbonate membrane for X-ray imaging

NASA Astrophysics Data System (ADS)

Mohammadian-Behbahani, Mohammad-Reza; Saramad, Shahyar; Mohammadi, Mohammad

2017-05-01

A combination of Finite Difference Time Domain (FDTD) and Monte Carlo (MC) methods is proposed for simulation and analysis of ZnO microscintillators grown in polycarbonate membrane. A planar 10 keV X-ray source irradiating the detector is simulated by MC method, which provides the amount of absorbed X-ray energy in the assembly. The transport of generated UV scintillation light and its propagation in the detector was studied by the FDTD method. Detector responses to different probable scintillation sites and under different energies of X-ray source from 10 to 25 keV are reported. Finally, the tapered geometry for the scintillators is proposed, which shows enhanced spatial resolution in comparison to cylindrical geometry for imaging applications.

Investigation of L X-ray intensity ratios in Pt induced by proton collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaur, Manpuneet; Kaur, Mandeep; Department of Physics, Punjabi University, Patiala, 147 002, Punjab

2015-08-28

A survey of literature on L X-ray parameters inspires us for taking up the present investigation. These parameters are useful to study atomic properties. In view of this, we report L X-ray intensity ratios for Pt, namely, L{sub ℓ} / L{sub α}, L{sub β} / L{sub α} and L{sub γ} / L{sub α} with proton collisions over the energy range 260 - 400 keV with an interval of 20 keV. The intention of research presented in this paper is to explore their energy dependence and comparison with theoretical calculations. These analyses will yield a data in the low energy regionmore » which assist in better clarity of proton induced X-ray emission phenomenon.« less

HIGH ENERGY, HIGH BRIGHTNESS X-RAYS PRODUCED BY COMPTON BACKSCATTERING AT THE LIVERMORE PLEIADES FACILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tremaine, A M; Anderson, S G; Betts, S

2005-05-19

PLEIADES (Picosecond Laser Electron Interaction for the Dynamic Evaluation of Structures) produces tunable 30-140 keV x-rays with 0.3-5 ps pulse lengths and up to 10{sup 7} photons/pulse by colliding a high brightness electron beam with a high power laser. The electron beam is created by an rf photo-injector system, accelerated by a 120 MeV linac, and focused to 20 {micro}m with novel permanent magnet quadrupoles. To produce Compton back scattered x-rays, the electron bunch is overlapped with a Ti:Sapphire laser that delivers 500 mJ, 100 fs, pulses to the interaction point. K-edge radiography at 115 keV on Uranium has verifiedmore » the angle correlated energy spectrum inherent in Compton scattering and high-energy tunability of the Livermore source. Current upgrades to the facility will allow laser pumping of targets synchronized to the x-ray source enabling dynamic diffraction and time-resolved studies of high Z materials. Near future plans include extending the radiation energies to >400 keV, allowing for nuclear fluorescence studies of materials.« less