X-ray emission as a potential hazard during ultrashort pulse laser material processing

NASA Astrophysics Data System (ADS)

Legall, Herbert; Schwanke, Christoph; Pentzien, Simone; Dittmar, Günter; Bonse, Jörn; Krüger, Jörg

2018-06-01

In laser machining with ultrashort laser pulses unwanted X-ray radiation in the keV range can be generated when a critical laser intensity is exceeded. Even if the emitted X-ray dose per pulse is low, high laser repetition rates can lead to an accumulation of X-ray doses beyond exposure safety limits. For 925 fs pulse duration at a center wavelength of 1030 nm, the X-ray emission was investigated up to an intensity of 2.6 × 1014 W/cm2. The experiments were performed in air with a thin disk laser at a repetition rate of 400 kHz. X-ray spectra and doses were measured for various planar target materials covering a wide range of the periodic table from aluminum to tungsten. Without radiation shielding, the measured radiation doses at this high repetition rate clearly exceed the regulatory limits. Estimations for an adequate radiation shielding are provided.

Temporal characteristic analysis of laser-modulated pulsed X-ray source for space X-ray communication

NASA Astrophysics Data System (ADS)

Hang, Shuang; Liu, Yunpeng; Li, Huan; Tang, Xiaobin; Chen, Da

2018-04-01

X-ray communication (XCOM) is a new communication type and is expected to realize high-speed data transmission in some special communication scenarios, such as deep space communication and blackout communication. This study proposes a high-speed modulated X-ray source scheme based on the laser-to-X-ray conversion. The temporal characteristics of the essential components of the proposed laser-modulated pulsed X-ray source (LMPXS) were analyzed to evaluate its pulse emission performance. Results show that the LMPXS can provide a maximum modulation rate up to 100 Mbps which is expected to significantly improve the data rate of XCOM.

A Deep Pulse Search in 11 Low Mass X-Ray Binaries

NASA Astrophysics Data System (ADS)

Patruno, A.; Wette, K.; Messenger, C.

2018-06-01

We present a systematic coherent X-ray pulsation search in 11 low mass X-ray binaries (LMXBs). We select a relatively broad variety of LMXBs, including persistent and transient sources, spanning orbital periods between 0.3 and 17 hr. We use about 3.6 Ms of data collected by the Rossi X-Ray Timing Explorer and XMM-Newton and apply a semi-coherent search strategy to look for weak and persistent pulses in a wide spin frequency range. We find no evidence for X-ray pulsations in these systems and consequently set upper limits on the pulsed sinusoidal semi-amplitude below 1.6% for ten outbursting/persistent LMXBs and 6% for a quiescent system; the upper limits are further refined, by searching a narrower parameter space around the outliers, down to 0.14%–0.78% and 2.9%, respectively. These results suggest that weak pulsations might not form in (most) non pulsating LMXBs.

Quasi-periodic pulsations in solar hard X-ray and microwave flares

NASA Technical Reports Server (NTRS)

Kosugi, Takeo; Kiplinger, Alan L.

1986-01-01

For more than a decade, various studies have pointed out that hard X-ray and microwave time profiles of some solar flares show quasi-periodic fluctuations or pulsations. Nevertheless, it was not until recently that a flare displaying large amplitude quasi-periodic pulsations in X-rays and microwaves was observed with good spectral coverage and with a sufficient time resolution. The event occurred on June 7, 1980, at approximately 0312 UT, and exhibits seven intense pulses with a quasi-periodicity of approximately 8 seconds in microwaves, hard X-rays, and gamma-ray lines. On May 12, 1983, at approximately 0253 UT, another good example of this type of flare was observed both in hard X-rays and in microwaves. Temporal and spectral characteristics of this flare are compared with the event of June 7, 1980. In order to further explore these observational results and theoretical scenarios, a study of nine additional quasi-periodic events were incorporated with the results from the two flares described. Analysis of these events are briefly summarized.

Temporal cross-correlation of x-ray free electron and optical lasers using soft x-ray pulse induced transient reflectivity.

PubMed

Krupin, O; Trigo, M; Schlotter, W F; Beye, M; Sorgenfrei, F; Turner, J J; Reis, D A; Gerken, N; Lee, S; Lee, W S; Hays, G; Acremann, Y; Abbey, B; Coffee, R; Messerschmidt, M; Hau-Riege, S P; Lapertot, G; Lüning, J; Heimann, P; Soufli, R; Fernández-Perea, M; Rowen, M; Holmes, M; Molodtsov, S L; Föhlisch, A; Wurth, W

2012-05-07

The recent development of x-ray free electron lasers providing coherent, femtosecond-long pulses of high brilliance and variable energy opens new areas of scientific research in a variety of disciplines such as physics, chemistry, and biology. Pump-probe experimental techniques which observe the temporal evolution of systems after optical or x-ray pulse excitation are one of the main experimental schemes currently in use for ultrafast studies. The key challenge in these experiments is to reliably achieve temporal and spatial overlap of the x-ray and optical pulses. Here we present measurements of the x-ray pulse induced transient change of optical reflectivity from a variety of materials covering the soft x-ray photon energy range from 500eV to 2000eV and outline the use of this technique to establish and characterize temporal synchronization of the optical-laser and FEL x-ray pulses.

Single-pulse coherent diffraction imaging using soft x-ray laser.

PubMed

Kang, Hyon Chol; Kim, Hyung Taek; Kim, Sang Soo; Kim, Chan; Yu, Tae Jun; Lee, Seong Ku; Kim, Chul Min; Kim, I Jong; Sung, Jae Hee; Janulewicz, Karol A; Lee, Jongmin; Noh, Do Young

2012-05-15

We report a coherent diffraction imaging (CDI) using a single 8 ps soft x-ray laser pulse at a wavelength of 13.9 nm. The soft x-ray pulse was generated by a laboratory-scale intense pumping laser providing coherent x-ray pulses up to the level of 10(11) photons/pulse. A spatial resolution below 194 nm was achieved with a single pulse, and it was shown that a resolution below 55 nm is feasible with improved detector capability. The single-pulse CDI might provide a way to investigate dynamics of nanoscale molecules or particles.

Macrophage and tumor cell responses to repetitive pulsed X-ray radiation

NASA Astrophysics Data System (ADS)

Buldakov, M. A.; Tretyakova, M. S.; Ryabov, V. B.; Klimov, I. A.; Kutenkov, O. P.; Kzhyshkowska, J.; Bol'shakov, M. A.; Rostov, V. V.; Cherdyntseva, N. V.

2017-05-01

To study a response of tumor cells and macrophages to the repetitive pulsed low-dose X-ray radiation. Methods. Tumor growth and lung metastasis of mice with an injected Lewis lung carcinoma were analysed, using C57Bl6. Monocytes were isolated from a human blood, using CD14+ magnetic beads. IL6, IL1-betta, and TNF-alpha were determined by ELISA. For macrophage phenotyping, a confocal microscopy was applied. “Sinus-150” was used for the generation of pulsed X-ray radiation (the absorbed dose was below 0.1 Gy, the pulse repetition frequency was 10 pulse/sec). The irradiation of mice by 0.1 Gy pulsed X-rays significantly inhibited the growth of primary tumor and reduced the number of metastatic colonies in the lung. Furthermore, the changes in macrophage phenotype and cytokine secretion were observed after repetitive pulsed X-ray radiation. Conclusion. Macrophages and tumor cells had a different response to a low-dose pulsed X-ray radiation. An activation of the immune system through changes of a macrophage phenotype can result in a significant antitumor effect of the low-dose repetitive pulsed X-ray radiation.

A search for millisecond periodic and quasi-periodic pulsations in low-mass X-ray binaries

NASA Technical Reports Server (NTRS)

Mereghetti, S.; Grindlay, J. E.

1987-01-01

The results of a Fourier analysis to detect fast periodic and quasi-periodic pulsations in the X-ray emission from the sources 4U 0614 + 091, 4U 1636 - 536, 4U 1735 - 44, 4U 1820 30, GX 5 - 1, GX 9 + 9, Ser X-1, and Cyg X-2 are presented. This search has been carried out for the first time in the soft energy band (0.2-2.0 keV), using data from the Einstein Observatory high resolution imager instrument. An approximate method of minimizing the decrease in search sensitivity produced by the Doppler shift of the pulse periods due to source orbital motion is discussed. No pulsations have been detected, and upper limits, which depend on the orbital parameters assumed for the sources, are set on the pulsed flux fraction.

ROSAT observations of pulsed soft X-ray emission from PSR 1055-52

NASA Technical Reports Server (NTRS)

Oegelman, Hakki; Finley, John P.

1993-01-01

Utilizing the position-sensitive proportional counter and the high-resolution imager aboard the orbiting X-ray observatory ROSAT, we have detected pulsations at the radio period from the pulsar PSR 1055-52. The pulse shapes are energy-dependent and show a transition at about 0.5 keV where the phase angle of the pulse peak changes by about -120 deg and the pulsed fraction increases from 11 percent to 63 percent toward larger energies. Simple spectral models are found to be unsatisfactory, while multicomponent models, such as a soft blackbody and hard power-law tail, yield better fits to the pulse-height data. The hard power-law tail is consistent with the extension of the recently reported EGRET results and may indicate a common emission mechanism for the X-ray through GeV gamma-ray regime. The soft blackbody component with T(infinity) = (7.5 +/- 0.6) x 10 exp 5 K, if interpreted as the initial cooling of a neutron star, is consistent with standard cooling models and does not require the presence of exotic components.

Attosecond time-energy structure of X-ray free-electron laser pulses

NASA Astrophysics Data System (ADS)

Hartmann, N.; Hartmann, G.; Heider, R.; Wagner, M. S.; Ilchen, M.; Buck, J.; Lindahl, A. O.; Benko, C.; Grünert, J.; Krzywinski, J.; Liu, J.; Lutman, A. A.; Marinelli, A.; Maxwell, T.; Miahnahri, A. A.; Moeller, S. P.; Planas, M.; Robinson, J.; Kazansky, A. K.; Kabachnik, N. M.; Viefhaus, J.; Feurer, T.; Kienberger, R.; Coffee, R. N.; Helml, W.

2018-04-01

The time-energy information of ultrashort X-ray free-electron laser pulses generated by the Linac Coherent Light Source is measured with attosecond resolution via angular streaking of neon 1s photoelectrons. The X-ray pulses promote electrons from the neon core level into an ionization continuum, where they are dressed with the electric field of a circularly polarized infrared laser. This induces characteristic modulations of the resulting photoelectron energy and angular distribution. From these modulations we recover the single-shot attosecond intensity structure and chirp of arbitrary X-ray pulses based on self-amplified spontaneous emission, which have eluded direct measurement so far. We characterize individual attosecond pulses, including their instantaneous frequency, and identify double pulses with well-defined delays and spectral properties, thus paving the way for X-ray pump/X-ray probe attosecond free-electron laser science.

HEAO 1 high-energy X-ray observations of Centaurus X-3

NASA Technical Reports Server (NTRS)

Howe, S. K.; Primini, F. A.; Bautz, M. W.; Lang, F. L.; Levine, A. M.; Lewin, W. H. G.

1983-01-01

Pulsations of 4.8 sec were detected up to energies above 38 keV by the present High Energy X-ray and Low Energy Gamma-Ray HEAO 1 satellite experiment observations of Cen X-3, and an analysis of the X-ray spectrum as a function of pulse phase indicates that the spectrum hardens during an interval of about 1.2 sec which lags the pulse peak by about 0.6 sec. The results of correlated observations of pulse period and X-ray intensity include (1) the detection of a high intensity state during which the pulse period is on the average increasing, (2) the measurement of comparable high intensities during episodes of both period increase and decrease, (3) the detection of X-ray pulsations at a much reduced level during a period of low intensity, and (4) the detection of a transition between spin-down, and spin-up episodes that coincides with a rapid decrease in X-ray intensity.

Impact of intense x-ray pulses on a NaI(Tl)-based gamma camera

NASA Astrophysics Data System (ADS)

Koppert, W. J. C.; van der Velden, S.; Steenbergen, J. H. L.; de Jong, H. W. A. M.

2018-03-01

In SPECT/CT systems x-ray and γ-ray imaging is performed sequentially. Simultaneous acquisition may have advantages, for instance in interventional settings. However, this may expose a gamma camera to relatively high x-ray doses and deteriorate its functioning. We studied the NaI(Tl) response to x-ray pulses with a photodiode, PMT and gamma camera, respectively. First, we exposed a NaI(Tl)-photodiode assembly to x-ray pulses to investigate potential crystal afterglow. Next, we exposed a NaI(Tl)-PMT assembly to 10 ms LED pulses (mimicking x-ray pulses) and measured the response to flashing LED probe-pulses (mimicking γ-pulses). We then exposed the assembly to x-ray pulses, with detector entrance doses of up to 9 nGy/pulse, and analysed the response for γ-pulse variations. Finally, we studied the response of a Siemens Diacam gamma camera to γ-rays while exposed to x-ray pulses. X-ray exposure of the crystal, read out with a photodiode, revealed 15% afterglow fraction after 3 ms. The NaI(Tl)-PMT assembly showed disturbances up to 10 ms after 10 ms LED exposure. After x-ray exposure however, responses showed elevated baselines, with 60 ms decay-time. Both for x-ray and LED exposure and after baseline subtraction, probe-pulse analysis revealed disturbed pulse height measurements shortly after exposure. X-ray exposure of the Diacam corroborated the elementary experiments. Up to 50 ms after an x-ray pulse, no events are registered, followed by apparent energy elevations up to 100 ms after exposure. Limiting the dose to 0.02 nGy/pulse prevents detrimental effects. Conventional gamma cameras exhibit substantial dead-time and mis-registration of photon energies up to 100 ms after intense x-ray pulses. This is due PMT limitations and due to afterglow in the crystal. Using PMTs with modified circuitry, we show that deteriorative afterglow effects can be reduced without noticeable effects on the PMT performance, up to x-ray pulse doses of 1 nGy.

High-intensity double-pulse X-ray free-electron laser

DOE PAGES

Marinelli, A.; Ratner, D.; Lutman, A. A.; ...

2015-03-06

The X-ray free-electron laser has opened a new era for photon science, improving the X-ray brightness by ten orders of magnitude over previously available sources. Similar to an optical laser, the spectral and temporal structure of the radiation pulses can be tailored to the specific needs of many experiments by accurately manipulating the lasing medium, that is, the electron beam. Here we report the generation of mJ-level two-colour hard X-ray pulses of few femtoseconds duration with an XFEL driven by twin electron bunches at the Linac Coherent Light Source. This performance represents an improvement of over an order of magnitudemore » in peak power over state-of-the-art two-colour XFELs. The unprecedented intensity and temporal coherence of this new two-colour X-ray free-electron laser enable an entirely new set of scientific applications, ranging from X-ray pump/X-ray probe experiments to the imaging of complex biological samples with multiple wavelength anomalous dispersion.« less

Coherent Multidimensional Core Spectroscopy of Molecules with Multiple X-ray pulses

NASA Astrophysics Data System (ADS)

Mukamel, Shaul

2017-04-01

Multidimensional spectroscopy uses sequences of optical pulses to study dynamical processes in complex molecules through correlation plots involving several time delay periods. Extensions of these techniques to the x-ray regime will be discussed. Ultrafast nonlinear x-ray spectroscopy is made possible by newly developed free electron laser and high harmonic generation sources. The attosecond duration of X-ray pulses and the atomic selectivity of core X-ray excitations offer a uniquely high spatial and temporal resolution. We demonstrate how stimulated Raman detection of an X-ray probe may be used to monitor the phase and dynamics of the nonequilibrium valence electronic state wavepacket created by e.g. photoexcitation, photoionization and Auger processes. Spectroscopy of multiplecore excitations provides a new window into electron correlations. Applications will be presented to long-range charge transfer in proteins and to excitation energy transfer in porphyrin arrays. Conical intersections (CoIn) dominate the pathways and outcomes of virtually all photophysical and photochemical molecular processes. Despite extensive experimental and theoretical effort CoIns have not been directly observed yet and the experimental evidence is being inferred from fast reaction rates and some vibrational signatures. Novel ultrafast X ray probes for these processes will be presented. Short X-ray pulses can directly detect the passage through a CoIn with the adequate temporal and spectral sensitivity. The technique is based on a coherent Raman process that employs a composite femtosecond/attosecond X-ray pulse to directly detect the electronic coherences (rather than populations) that are generated as the system passes through the CoIn. Streaking of time-resolved photoelectron spectroscopy (TRPES) signals offers another powerful window into the joint electronic/vibrational dynamics at concial intersections. Strong coupling of molecules to the vacuum field of micro cavities can modify

Few-cycle pulse generation in an x-ray free-electron laser.

PubMed

Dunning, D J; McNeil, B W J; Thompson, N R

2013-03-08

A method is proposed to generate trains of few-cycle x-ray pulses from a free-electron laser (FEL) amplifier via a compact "afterburner" extension consisting of several few-period undulator sections separated by electron chicane delays. Simulations show that in the hard x ray (wavelength ~0.1 nm; photon energy ~10 keV) and with peak powers approaching normal FEL saturation (GW) levels, root mean square pulse durations of 700 zs may be obtained. This is approximately two orders of magnitude shorter than that possible for normal FEL amplifier operation. The spectrum is discretely multichromatic with a bandwidth envelope increased by approximately 2 orders of magnitude over unseeded FEL amplifier operation. Such a source would significantly enhance research opportunity in atomic dynamics and push capability toward nuclear dynamics.

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.

Establishing nonlinearity thresholds with ultraintense X-ray pulses

NASA Astrophysics Data System (ADS)

Szlachetko, Jakub; Hoszowska, Joanna; Dousse, Jean-Claude; Nachtegaal, Maarten; Błachucki, Wojciech; Kayser, Yves; Sà, Jacinto; Messerschmidt, Marc; Boutet, Sebastien; Williams, Garth J.; David, Christian; Smolentsev, Grigory; van Bokhoven, Jeroen A.; Patterson, Bruce D.; Penfold, Thomas J.; Knopp, Gregor; Pajek, Marek; Abela, Rafael; Milne, Christopher J.

2016-09-01

X-ray techniques have evolved over decades to become highly refined tools for a broad range of investigations. Importantly, these approaches rely on X-ray measurements that depend linearly on the number of incident X-ray photons. The advent of X-ray free electron lasers (XFELs) is opening the ability to reach extremely high photon numbers within ultrashort X-ray pulse durations and is leading to a paradigm shift in our ability to explore nonlinear X-ray signals. However, the enormous increase in X-ray peak power is a double-edged sword with new and exciting methods being developed but at the same time well-established techniques proving unreliable. Consequently, accurate knowledge about the threshold for nonlinear X-ray signals is essential. Herein we report an X-ray spectroscopic study that reveals important details on the thresholds for nonlinear X-ray interactions. By varying both the incident X-ray intensity and photon energy, we establish the regimes at which the simplest nonlinear process, two-photon X-ray absorption (TPA), can be observed. From these measurements we can extract the probability of this process as a function of photon energy and confirm both the nature and sub-femtosecond lifetime of the virtual intermediate electronic state.

Establishing nonlinearity thresholds with ultraintense X-ray pulses

DOE PAGES

Szlachetko, Jakub; Hoszowska, Joanna; Dousse, Jean-Claude; ...

2016-09-13

X-ray techniques have evolved over decades to become highly refined tools for a broad range of investigations. Importantly, these approaches rely on X-ray measurements that depend linearly on the number of incident X-ray photons. The advent of X-ray free electron lasers (XFELs) is opening the ability to reach extremely high photon numbers within ultrashort X-ray pulse durations and is leading to a paradigm shift in our ability to explore nonlinear X-ray signals. However, the enormous increase in X-ray peak power is a double-edged sword with new and exciting methods being developed but at the same time well-established techniques proving unreliable.more » Consequently, accurate knowledge about the threshold for nonlinear X-ray signals is essential. Here in this paper we report an X-ray spectroscopic study that reveals important details on the thresholds for nonlinear X-ray interactions. By varying both the incident X-ray intensity and photon energy, we establish the regimes at which the simplest nonlinear process, two-photon X-ray absorption (TPA), can be observed. From these measurements we can extract the probability of this process as a function of photon energy and confirm both the nature and sub-femtosecond lifetime of the virtual intermediate electronic state.« less

A photodiode amplifier system for pulse-by-pulse intensity measurement of an x-ray free electron laser.

PubMed

Kudo, Togo; Tono, Kensuke; Yabashi, Makina; Togashi, Tadashi; Sato, Takahiro; Inubushi, Yuichi; Omodani, Motohiko; Kirihara, Yoichi; Matsushita, Tomohiro; Kobayashi, Kazuo; Yamaga, Mitsuhiro; Uchiyama, Sadayuki; Hatsui, Takaki

2012-04-01

We have developed a single-shot intensity-measurement system using a silicon positive-intrinsic-negative (PIN) photodiode for x-ray pulses from an x-ray free electron laser. A wide dynamic range (10(3)-10(11) photons/pulse) and long distance signal transmission (>100 m) were required for this measurement system. For this purpose, we developed charge-sensitive and shaping amplifiers, which can process charge pulses with a wide dynamic range and variable durations (ns-μs) and charge levels (pC-μC). Output signals from the amplifiers were transmitted to a data acquisition system through a long cable in the form of a differential signal. The x-ray pulse intensities were calculated from the peak values of the signals by a waveform fitting procedure. This system can measure 10(3)-10(9) photons/pulse of ~10 keV x-rays by direct irradiation of a silicon PIN photodiode, and from 10(7)-10(11) photons/pulse by detecting the x-rays scattered by a diamond film using the silicon PIN photodiode. This system gives a relative accuracy of ~10(-3) with a proper gain setting of the amplifiers for each measurement. Using this system, we succeeded in detecting weak light at the developmental phase of the light source, as well as intense light during lasing of the x-ray free electron laser. © 2012 American Institute of Physics

High-average-power 2-kHz laser for generation of ultrashort x-ray pulses.

PubMed

Jiang, Yan; Lee, Taewoo; Li, Wei; Ketwaroo, Gyanprakash; Rose-Petruck, Christoph G

2002-06-01

We describe a Ti:sapphire-based laser-x-ray system specifically designed for generation of ultrafast x-ray pulses in the tenths-of-nanometers spectral range at a 2-kHz repetition rate. To obtain high-contrast laser pulses we divide the laser system into a section for generation of microjoule, high-contrast pulses with pulse cleaning and a subsequent section for chirped-pulse amplification and pulse compression. This laser section operates in conjunction with an x-ray-generation section based on a moving copper wire in a He atmosphere. The high reliability of the entire system permits maintenance-free production of x-ray pulses over tens of hours. Average x-ray fluxes of 10(13) photons/(s 4pi sr 1 keV) at 3 keV and 10(9) photons/(s 4pi sr) above 5 keV of photon energy are produced.

X-Ray Pulse Selector With 2 ns Lock-in Phase Setting And Stability

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

Lindenau, B.; Raebiger, J.; Polachowski, S.

2004-05-12

Selector devices, which are based on magnetically suspended, high speed triangular shutter rotors, have been designed and built in cooperation with ESRF, APS, and recently Spring-8 for time resolved studies with isolated x-ray pulses at white beam lines. The x-ray pulse selection is accomplished by means of a beam channel along one of the edges of the triangular rotor, which opens once per revolution. Entrance and exit apertures of the channel can be designed wedge shaped for variable tuning of the channel height between 0.1 mm to 0.9 mm. At the 1 kHz maximum operation frequency of a 220 mmmore » diameter disk with 190 mm channel length, the practicable open times of the channel are demonstrated to range down to 200 ns. The selector drive electronics is directly coupled to the storage ring RF clock for rotational phase control. It allows for continuous selector operation in phase locked mode to the temporal pulse structure of the synchrotron at 2 ns RMS stability. The phase angle between the pulse transmission period and the synchrotron bunch sequence can be adjusted with similar precision for X-ray pulse selection according to the experimental needs. ID09, Michael Wulff ; BioCARS 14-BM, Reinhard Pahl; BL40-XU, Shin-ichi Adachi.« less

Single-pulse x-ray diffraction using polycapillary optics for in situ dynamic diffraction

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

Maddox, B. R., E-mail: maddox3@llnl.gov; Akin, M. C., E-mail: akin1@llnl.gov; Teruya, A.

2016-08-15

Diagnostic use of single-pulse x-ray diffraction (XRD) at pulsed power facilities can be challenging due to factors such as the high flux and brightness requirements for diffraction and the geometric constraints of experimental platforms. By necessity, the x-ray source is usually positioned very close, within a few inches of the sample. On dynamic compression platforms, this puts the x-ray source in the debris field. We coupled x-ray polycapillary optics to a single-shot needle-and-washer x-ray diode source using a laser-based alignment scheme to obtain high-quality x-ray diffraction using a single 16 ns x-ray pulse with the source >1 m from themore » sample. The system was tested on a Mo sample in reflection geometry using 17 keV x-rays from a Mo anode. We also identified an anode conditioning effect that increased the x-ray intensity by 180%. Quantitative measurements of the x-ray focal spot produced by the polycapillary yielded a total x-ray flux on the sample of 3.3 ± 0.5 × 10{sup 7} molybdenum Kα photons.« less

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.

Method and apparatus for producing durationally short ultraviolet or x-ray laser pulses

DOEpatents

MacGowan, B.J.; Matthews, D.L.; Trebes, J.E.

1987-05-05

A method and apparatus is disclosed for producing ultraviolet or x- ray laser pulses of short duration. An ultraviolet or x-ray laser pulse of long duration is progressively refracted, across the surface of an opaque barrier, by a streaming plasma that is produced by illuminating a solid target with a pulse of conventional line focused high power laser radiation. The short pulse of ultraviolet or x-ray laser radiation, which may be amplified to high power, is separated out by passage through a slit aperture in the opaque barrier.

Accretion torques in X-ray pulsars

NASA Technical Reports Server (NTRS)

Rappaport, S.; Joss, P. C.

1977-01-01

An analysis of the accretion process in an X-ray pulsar, whereby angular momentum is transferred to the star and its rotation period is changed, is presented, and an expression for the fractional rate of change of the pulse period in terms of X-ray luminosity and other star parameters is derived. It is shown that observed characteristic spin-up time scales for seven X-ray pulsars strongly support the view that in every source (1) the pulse period reflects the rotation period of a compact object, (2) the accretion is mediated by a disk surrounding the compact object and rotating in the same sense, and (3) the compact object is a neutron star rather than a white dwarf.

THz pulses from 4th generation X-ray light sources: Perspectives for fully synchronized THz pump X-ray probe experiments

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

Gensch, M.

2010-02-03

In this paper the prospects of terahertz (THz) pulses generated at 4th generation X-ray light sources are presented on the example of recent results from a prototype set-up at the soft X-ray FEL FLASH. It is shown, that the THz pulses from the relativistic ultra short electron bunches have unique properties, that at FLASH are utilized for novel THz pump X-ray probe experiments with a robust few fs resolution. Based on these experiences it is discussed, how future facilities can benefit from implementation of similar or further improved instrumentation.

Method and apparatus for producing durationally short ultraviolet or X-ray laser pulses

DOEpatents

MacGowan, Brian J.; Matthews, Dennis L.; Trebes, James E.

1988-01-01

A method and apparatus is disclosed for producing ultraviolet or X-ray laser pulses of short duration (32). An ultraviolet or X-ray laser pulse of long duration (12) is progressively refracted, across the surface of an opaque barrier (28), by a streaming plasma (22) that is produced by illuminating a solid target (16, 18) with a pulse of conventional line focused high power laser radiation (20). The short pulse of ultraviolet or X-ray laser radiation (32), which may be amplified to high power (40, 42), is separated out by passage through a slit aperture (30) in the opaque barrier (28).

Vela X-1 pulse timing. II - Variations in pulse frequency

NASA Technical Reports Server (NTRS)

Deeter, J. E.; Boynton, P. E.; Lamb, F. K.; Zylstra, G.

1989-01-01

The pulsed X-ray emission of Vela X-1 during May 1978 and December-January 1978-1979 is investigated analytically on the basis of published satellite observations. The data are compiled in tables and graphs and discussed in detail, with reference to data for the entire 1975-1982 period. Variations in pulse frequency are identified on time scales from 2 to 2600 days; the lower nine octaves are characterized as white noise (or random walk in pulse frequency), while the longer-period variations are attributed to changes in neutron-star rotation rates.

Hitomi X-ray studies of giant radio pulses from the Crab pulsar

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 O.; 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; Oshimizu, Kenya; 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, Shiníchiro; 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, Shiníchiro; 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; Terasawa, Toshio; Sekido, Mamoru; Takefuji, Kazuhiro; Kawai, Eiji; Misawa, Hiroaki; Tsuchiya, Fuminori; Yamazaki, Ryo; Kobayashi, Eiji; Kisaka, Shota; Aoki, Takahiro

2018-03-01

To search for giant X-ray pulses correlated with the giant radio pulses (GRPs) from the Crab pulsar, we performed a simultaneous observation of the Crab pulsar with the X-ray satellite Hitomi in the 2-300 keV band and the Kashima NICT radio telescope in the 1.4-1.7 GHz band with a net exposure of about 2 ks on 2016 March 25, just before the loss of the Hitomi mission. The timing performance of the Hitomi instruments was confirmed to meet the timing requirement and about 1000 and 100 GRPs were simultaneously observed at the main pulse and inter-pulse phases, respectively, and we found no apparent correlation between the giant radio pulses and the X-ray emission in either the main pulse or inter-pulse phase. All variations are within the 2 σ fluctuations of the X-ray fluxes at the pulse peaks, and the 3 σ upper limits of variations of main pulse or inter-pulse GRPs are 22% or 80% of the peak flux in a 0.20 phase width, respectively, in the 2-300 keV band. The values for main pulse or inter-pulse GRPs become 25% or 110%, respectively, when the phase width is restricted to the 0.03 phase. Among the upper limits from the Hitomi satellite, those in the 4.5-10 keV and 70-300 keV bands are obtained for the first time, and those in other bands are consistent with previous reports. Numerically, the upper limits of the main pulse and inter-pulse GRPs in the 0.20 phase width are about (2.4 and 9.3) × 10-11 erg cm-2, respectively. No significant variability in pulse profiles implies that the GRPs originated from a local place within the magnetosphere. Although the number of photon-emitting particles should temporarily increase to account for the brightening of the radio emission, the results do not statistically rule out variations correlated with the GRPs, because the possible X-ray enhancement may appear due to a >0.02% brightening of the pulse-peak flux under such conditions.

Finding a 24 Day Orbital Period for the X-Ray Binary 1A 1118-616

NASA Technical Reports Server (NTRS)

Staubert, R.; Pottschmidt, K.; Doroshenko, V.; Wilms, J.; Suchy, S.; Rothschild, R.; Santangelo, A.

2010-01-01

We report the first determination of the binary period and the orbital ephemeris of the Be X-ray binary containing the pulsar IA 1118-616 (35 years after the discovery of the source). The orbital period is found to be P(sub orb) = 24.0+/-0.4 days. The source was observed by RXTE during its last big X-ray outburst in January 2009, peaking at MJD 54845.4. This outburst was sampled by taking short observations every few days, covering an elapsed time comparable to the orbital period. Using the phase connection technique, pulse arrival time delays could be measured and an orbital solution determined. The data are consistent with a circular orbit, the time of 90 degrees longitude was found to be T,/2 = MJD 54845.37(10), coincident with the peak X-ray flux.

Isolated terawatt attosecond hard X-ray pulse generated from single current spike.

PubMed

Shim, Chi Hyun; Parc, Yong Woon; Kumar, Sandeep; Ko, In Soo; Kim, Dong Eon

2018-05-10

Isolated terawatt (TW) attosecond (as) hard X-ray pulse is greatly desired for four-dimensional investigations of natural phenomena with picometer spatial and attosecond temporal resolutions. Since the demand for such sources is continuously increasing, the possibility of generating such pulse by a single current spike without the use of optical or electron delay units in an undulator line is addressed. The conditions of a current spike (width and height) and a modulation laser pulse (wavelength and power) is also discussed. We demonstrate that an isolated TW-level as a hard X-ray can be produced by a properly chosen single current spike in an electron bunch with simulation results. By using realistic specifications of an electron bunch of the Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL), we show that an isolated, >1.0 TW and ~36 as X-ray pulse at 12.4 keV can be generated in an optimized-tapered undulator line. This result opens a new vista for current XFEL operation: the attosecond XFEL.

Nonlinear resonance scattering of femtosecond X-ray pulses on atoms in plasmas

NASA Astrophysics Data System (ADS)

Rosmej, F. B.; Astapenko, V. A.; Lisitsa, V. S.; Moroz, N. N.

2017-11-01

It is shown that for sufficiently short pulses the resonance scattering probability becomes a nonlinear function of the pulse duration. For fs X-ray pulses scattered on atoms in plasmas maxima and minima develop in the nonlinear regime whereas in the limit of long pulses the probability becomes linear and turns over into the standard description of the electromagnetic pulse scattering. Numerical calculations are carried out in terms of a generalized scattering probability for the total time of pulse duration including fine structure splitting and ion Doppler broadening in hot plasmas. For projected X-ray monocycles, the generalized nonlinear approach differs by 1-2 orders of magnitude from the standard theory.

Generation of High-Power High-Intensity Short X-Ray Free-Electron-Laser Pulses

DOE PAGES

Guetg, Marc W.; Lutman, Alberto A.; Ding, Yuantao; ...

2018-01-03

X-ray free-electron lasers combine a high pulse power, short pulse length, narrow bandwidth, and high degree of transverse coherence. Any increase in the photon pulse power, while shortening the pulse length, will further push the frontier on several key x-ray free-electron laser applications including single-molecule imaging and novel nonlinear x-ray methods. This Letter shows experimental results at the Linac Coherent Light Source raising its maximum power to more than 300% of the current limit while reducing the photon pulse length to 10 fs. As a result, this was achieved by minimizing residual transverse-longitudinal centroid beam offsets and beam yaw andmore » by correcting the dispersion when operating over 6 kA peak current with a longitudinally shaped beam.« less

Generation of High-Power High-Intensity Short X-Ray Free-Electron-Laser Pulses

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

Guetg, Marc W.; Lutman, Alberto A.; Ding, Yuantao

X-ray free-electron lasers combine a high pulse power, short pulse length, narrow bandwidth, and high degree of transverse coherence. Any increase in the photon pulse power, while shortening the pulse length, will further push the frontier on several key x-ray free-electron laser applications including single-molecule imaging and novel nonlinear x-ray methods. This Letter shows experimental results at the Linac Coherent Light Source raising its maximum power to more than 300% of the current limit while reducing the photon pulse length to 10 fs. As a result, this was achieved by minimizing residual transverse-longitudinal centroid beam offsets and beam yaw andmore » by correcting the dispersion when operating over 6 kA peak current with a longitudinally shaped beam.« less

Counting-loss correction for X-ray spectroscopy using unit impulse pulse shaping.

PubMed

Hong, Xu; Zhou, Jianbin; Ni, Shijun; Ma, Yingjie; Yao, Jianfeng; Zhou, Wei; Liu, Yi; Wang, Min

2018-03-01

High-precision measurement of X-ray spectra is affected by the statistical fluctuation of the X-ray beam under low-counting-rate conditions. It is also limited by counting loss resulting from the dead-time of the system and pile-up pulse effects, especially in a high-counting-rate environment. In this paper a detection system based on a FAST-SDD detector and a new kind of unit impulse pulse-shaping method is presented, for counting-loss correction in X-ray spectroscopy. The unit impulse pulse-shaping method is evolved by inverse deviation of the pulse from a reset-type preamplifier and a C-R shaper. It is applied to obtain the true incoming rate of the system based on a general fast-slow channel processing model. The pulses in the fast channel are shaped to unit impulse pulse shape which possesses small width and no undershoot. The counting rate in the fast channel is corrected by evaluating the dead-time of the fast channel before it is used to correct the counting loss in the slow channel.

X-ray pulsars in nearby irregular galaxies

NASA Astrophysics Data System (ADS)

Yang, Jun

2018-01-01

The Small Magellanic Cloud (SMC), Large Magellanic Cloud (LMC) and Irregular Galaxy IC 10 are valuable laboratories to study the physical, temporal and statistical properties of the X-ray pulsar population with multi-satellite observations, in order to probe fundamental physics. The known distance of these galaxies can help us easily categorize the luminosity of the pulsars and their age difference can be helpful for for studying the origin and evolution of compact objects. Therefore, a complete archive of 116 XMM-Newton PN, 151 Chandra (Advanced CCD Imaging Spectrometer) ACIS, and 952 RXTE PCA observations for the pulsars in the Small Magellanic Cloud (SMC) were collected and analyzed, along with 42 XMM-Newton and 30 Chandra observations for the Large Magellanic Cloud, spanning 1997-2014. From a sample of 67 SMC pulsars we generate a suite of products for each pulsar detection: spin period, flux, event list, high time-resolution light-curve, pulse-profile, periodogram, and X-ray spectrum. Combining all three satellites, I generated complete histories of the spin periods, pulse amplitudes, pulsed fractions and X-ray luminosities. Many of the pulsars show variations in pulse period due to the combination of orbital motion and accretion torques. Long-term spin-up/down trends are seen in 28/25 pulsars respectively, pointing to sustained transfer of mass and angular momentum to the neutron star on decadal timescales. The distributions of pulse detection and flux as functions of spin period provide interesting findings: mapping boundaries of accretion-driven X-ray luminosity, and showing that fast pulsars (P<10 s) are rarely detected, which yet are more prone to giant outbursts. In parallel we compare the observed pulse profiles to our general relativity (GR) model of X-ray emission in order to constrain the physical parameters of the pulsars.In addition, we conduct a search for optical counterparts to X-ray sources in the local dwarf galaxy IC 10 to form a comparison

X-ray two-photon absorption with high fluence XFEL pulses

DOE PAGES

Hoszowska, Joanna; Szlachetko, J.; Dousse, J. -Cl.; ...

2015-09-07

Here, we report on nonlinear interaction of solid Fe with intense femtosecond hard x-ray free-electron laser (XFEL) pulses. The experiment was performed at the CXI end-station of the Linac Coherent Light Source (LCLS) by means of high- resolution x-ray emission spectroscopy. The focused x-ray beam provided extreme fluence of ~10 5 photons/Å 2. Two-photon absorption leading to K-shell hollow atom formation and to single K-shell ionization of solid Fe was investigated.

A Non-thermal Pulsed X-Ray Emission of AR Scorpii

NASA Astrophysics Data System (ADS)

Takata, J.; Hu, C.-P.; Lin, L. C. C.; Tam, P. H. T.; Pal, P. S.; Hui, C. Y.; Kong, A. K. H.; Cheng, K. S.

2018-02-01

We report the analysis result of UV/X-ray emission from AR Scorpii, which is an intermediate polar (IP) composed of a magnetic white dwarf and an M-type star, with the XMM-Newton data. The X-ray/UV emission clearly shows a large variation over the orbit, and their intensity maximum (or minimum) is located at the superior conjunction (or inferior conjunction) of the M star orbit. The hardness ratio of the X-ray emission shows a small variation over the orbital phase and shows no indication of the absorption by an accretion column. These properties are naturally explained by the emission from the M star surface rather than that from the accretion column on the white dwarf’s (WD) star, which is similar to usual IPs. Additionally, the observed X-ray emission also modulates with the WD’s spin with a pulse fraction of ∼14%. The peak position is aligned in the optical/UV/X-ray band. This supports the hypothesis that the electrons in AR Scorpii are accelerated to a relativistic speed and emit non-thermal photons via the synchrotron radiation. In the X-ray bands, evidence of the power-law spectrum is found in the pulsed component, although the observed emission is dominated by the optically thin thermal plasma emissions with several different temperatures. It is considered that the magnetic dissipation/reconnection process on the M star surface heats up the plasma to a temperature of several keV and also accelerates the electrons to the relativistic speed. The relativistic electrons are trapped in the WD’s closed magnetic field lines by the magnetic mirror effect. In this model, the observed pulsed component is explained by the emissions from the first magnetic mirror point.

The method of pulsed x-ray detection with a diode laser.

PubMed

Liu, Jun; Ouyang, Xiaoping; Zhang, Zhongbing; Sheng, Liang; Chen, Liang; Tan, Xinjian; Weng, Xiufeng

2016-12-01

A new class of pulsed X-ray detection methods by sensing carrier changes in a diode laser cavity has been presented and demonstrated. The proof-of-principle experiments on detecting pulsed X-ray temporal profile have been done through the diode laser with a multiple quantum well active layer. The result shows that our method can achieve the aim of detecting the temporal profile of a pulsed X-ray source. We predict that there is a minimum value for the pre-bias current of the diode laser by analyzing the carrier rate equation, which exists near the threshold current of the diode laser chip in experiments. This behaviour generally agrees with the characterizations of theoretical analysis. The relative sensitivity is estimated at about 3.3 × 10 -17 C ⋅ cm 2 . We have analyzed the time scale of about 10 ps response with both rate equation and Monte Carlo methods.

Liquid explosions induced by X-ray laser pulses

DOE PAGES

Stan, Claudiu A.; Milathianaki, Despina; Laksmono, Hartawan; ...

2016-05-23

Explosions are spectacular and intriguing phenomena that expose the dynamics of matter under extreme conditions. We investigated, using time-resolved imaging, explosions induced by ultraintense X-ray laser pulses in water drops and jets. Our observations revealed an explosive vaporization followed by high-velocity interacting flows of liquid and vapour, and by the generation of shock trains in the liquid jets. These flows are different from those previously observed in laser ablation, owing to a simpler spatial pattern of X-ray absorption. We show that the explosion dynamics in our experiments is consistent with a redistribution of absorbed energy, mediated by a pressure ormore » shock wave in the liquid, and we model the effects of explosions, including their adverse impact on X-ray laser experiments. As a result, X-ray laser explosions have predictable dynamics that may prove useful for controlling the state of pure liquids over broad energy scales and timescales, and for triggering pressure-sensitive molecular dynamics in solutions.« less

Pulsed x-ray generator for commercial gas lasers

NASA Astrophysics Data System (ADS)

Bollanti, S.; Bonfigli, F.; Di Lazzaro, P.; Flora, F.; Giordano, G.; Letardi, T.; Murra, D.; Schina, G.; Zheng, C. E.

2001-10-01

We have designed and tested a 1-m-long x-ray diode based on innovative plasma cathodes, which exploit commercial spark plugs as electron emitters. Based on the results of a numerical study, we optimized both diode geometry (e.g., the angle between anode and cathode surfaces, the thickness of the Al window) and electrical circuitry (e.g., the capacitance in series to each spark plug, the peak voltage of the anode) of our x-ray generator. The overall result is a simple and efficient circuitry, giving a total diode current in excess of 2.1 kA with a breakdown voltage of 70 kV, which generates a 50 ns rise-time x-ray pulse with a spatially averaged dosage of up to 6×10-4 Gy when using a Pb-wrapped anode. The double-diode x-ray generator was operated for 1.5×106 shots at a repetition rate of up to 30 Hz, and the lifetime test was interrupted without any fault. During the lifetime test, it was not necessary to adjust any working parameter. At the end of the lifetime test, the x-ray emission uniformity was better than 80% along the longitudinal axis. This x-ray generator has a lifetime, reliability, and cost fitting the requirements of industrial users. Among the broad range of potential applications, this x-ray generator is particularly suitable to ionize discharge pumped gas lasers, like TEA CO2 and excimer lasers, including those operated by x-ray triggered discharges.

Short x-ray pulse generation using deflecting cavities at the Advanced Photon Source.

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

Sajaev, V.; Borland, M.; Chae, Y.-C.

2007-11-11

Storage-ring-based third-generation light sources can provide intense radiation pulses with durations as short as 100 ps. However, there is growing interest within the synchrotron radiation user community in performing experiments with much shorter X-ray pulses. Zholents et al. [Nucl. Instr. and Meth. A 425 (1999) 385] recently proposed using RF orbit deflection to generate sub-ps X-ray pulses. In this scheme, two deflecting cavities are used to deliver a longitudinally dependent vertical kick to the beam. An optical slit can then be used to slice out a short part of the radiation pulse. Implementation of this scheme is planned for onemore » APS beamline in the near future. In this paper, we summarize our feasibility study of this method and the expected X-ray beam parameters. We find that a pulse length of less than two picoseconds can be achieved.« less

Exploring coherent electron excitation and migration dynamics by electron diffraction with ultrashort X-ray pulses.

PubMed

Yuan, Kai-Jun; Bandrauk, André D

2017-10-04

Exploring ultrafast charge migration is of great importance in biological and chemical reactions. We present a scheme to monitor attosecond charge migration in molecules by electron diffraction with spatial and temporal resolutions from ab initio numerical simulations. An ultraviolet pulse creates a coherent superposition of electronic states, after which a time-delayed attosecond X-ray pulse is used to ionize the molecule. It is found that diffraction patterns in the X-ray photoelectron spectra show an asymmetric structure, which is dependent on the time delay between the pump-probe pulses, encoding the information of molecular orbital symmetry and chemical bonding. We describe these phenomena by developing an electronic time-dependent ultrafast molecular photoionization model of a coherent superposition state. The periodical distortion of electron diffraction patterns illustrates the evolution of the electronic coherence, providing a tool for attosecond imaging of ultrafast molecular reaction processes.

The fluid dynamics of microjet explosions caused by extremely intense X-ray pulses

NASA Astrophysics Data System (ADS)

Stan, Claudiu; Laksmono, Hartawan; Sierra, Raymond; Milathianaki, Despina; Koglin, Jason; Messerschmidt, Marc; Williams, Garth; Demirci, Hasan; Botha, Sabine; Nass, Karol; Stone, Howard; Schlichting, Ilme; Shoeman, Robert; Boutet, Sebastien

2014-11-01

Femtosecond X-ray scattering experiments at free-electron laser facilities typically requires liquid jet delivery methods to bring samples to the region of interaction with X-rays. We have imaged optically the damage process in water microjets due to intense hard X-ray pulses at the Linac Coherent Light Source (LCLS), using time-resolved imaging techniques to record movies at rates up to half a billion frames per second. For pulse energies larger than a few percent of the maximum pulse energy available at LCLS, the X-rays deposit energies much larger than the latent heat of vaporization in water, and induce a phase explosion that opens a gap in the jet. The LCLS pulses last a few tens of femtoseconds, but the full evolution of the broken jet is orders of magnitude slower - typically in the microsecond range - due to complex fluid dynamics processes triggered by the phase explosion. Although the explosion results in a complex sequence of phenomena, they lead to an approximately self-similar flow of the liquid in the jet.

Pile-up corrections in laser-driven pulsed X-ray sources

NASA Astrophysics Data System (ADS)

Hernández, G.; Fernández, F.

2018-06-01

A formalism for treating the pile-up produced in solid-state detectors by laser-driven pulsed X-ray sources has been developed. It allows the direct use of X-ray spectroscopy without artificially decreasing the number of counts in the detector, assuming the duration of a pulse is much shorter than the detector response time and the loss of counts from the energy window of the detector can be modeled or neglected. Experimental application shows that having a small amount of pile-up subsequently corrected improves the signal-to-noise ratio, which would be more beneficial than the strict single-hit condition usually imposed on this detectors.

Pulse pile-up in hard X-ray detector systems. [for solar X-rays

NASA Technical Reports Server (NTRS)

Datlowe, D. W.

1975-01-01

When pulse-height spectra are measured by a nuclear detection system at high counting rates, the probability that two or more pulses will arrive within the resolving time of the system is significant. This phenomenon, pulse pile-up, distorts the pulse-height spectrum and must be considered in the interpretation of spectra taken at high counting rates. A computational technique for the simulation of pile-up is developed. The model is examined in the three regimes where (1) the time between pulses is long compared to the detector-system resolving time, (2) the time between pulses is comparable to the resolving time, and (3) many pulses occur within the resolving time. The technique is used to model the solar hard X-ray experiment on the OSO-7 satellite; comparison of the model with data taken during three large flares shows excellent agreement. The paper also describes rule-of-thumb tests for pile-up and identifies the important detector design factors for minimizing pile-up, i.e., thick entrance windows and short resolving times in the system electronics.

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

DOE PAGES

Miaja-Avila, L.; O'Neil, G. C.; Uhlig, J.; ...

2015-03-02

We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ~10 6 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >10 7 laser pulses, wemore » also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.« less

Evidence For Quasi-Periodic X-ray Dips From An Ultraluminous X-ray Source: Implications for the Binary Motion

NASA Technical Reports Server (NTRS)

Pasham, Dheeraj R.; Strohmayer, Tod E.

2013-01-01

We report results from long-term (approx.1240 days) X-ray (0.3-8.0 keV) monitoring of the ultraluminous X-ray source NGC 5408 X-1 with the Swift/X-Ray Telescope. Here we expand on earlier work by Strohmayer (2009) who used only a part of the present data set. Our primary results are: (1) the discovery of sharp, quasi-periodic, energy-independent dips in the X-ray intensity that recur on average every 243 days, (2) the detection of an energy dependent (variability amplitude decreases with increasing energy), quasi-sinusoidal X-ray modulation with a period of 112.6 +/- 4 days, the amplitude of which weakens during the second half of the light curve, and (3) spectral evidence for an increase in photoelectric absorption during the last continuous segment of the data. We interpret the X-ray modulations within the context of binary motion in analogy to that seen in high-inclination accreting X-ray binaries. If correct, this implies that NGC 5408 X-1 is in a binary with an orbital period of 243 +/- 23 days, in contrast to the 115.5 day quasi-sinusoidal period previously reported by Strohmayer (2009). We discuss the overall X-ray modulation within the framework of accretion via Roche-lobe overflow of the donor star. In addition, if the X-ray modulation is caused by vertically structured obscuring material in the accretion disk, this would imply a high value for the inclination of the orbit. A comparison with estimates from accreting X-ray binaries suggests an inclination > or approx.70deg. We note that, in principle, a precessing accretion disk could also produce the observed X-ray modulations.

High energy X-ray observations of CYG X-3 from from OSO-8: Further evidence of a 34.1 day period

NASA Technical Reports Server (NTRS)

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

1981-01-01

The X-ray source Cyg X-3 (=4U2030+40) was observed with the high energy X-ray spectrometer on OSO-8 for two weeks in 1975 and in 1976 and for one week in 1977. No change in spectral shape and intensity above 23 keV was observed from year to year. No correlation is observed between the source's intensity and the phase of the 34.1 day period discovered by Molteni, et al. (1980). The pulsed fraction of the 4.8 hour light curve between 23 and 73 keV varies from week to week, however, and the magnitude of the pulsed fraction appears to be correlated with the 34.1 day phase. No immediate explanation of this behavior is apparent in terms of previously proposed models of the source.

The use of short and wide x-ray pulses for time-of-flight x-ray Compton Scatter Imaging in cargo security

NASA Astrophysics Data System (ADS)

Calvert, Nick; Betcke, Marta M.; Cresswell, John R.; Deacon, Alick N.; Gleeson, Anthony J.; Judson, Daniel S.; Mason, Peter; McIntosh, Peter A.; Morton, Edward J.; Nolan, Paul J.; Ollier, James; Procter, Mark G.; Speller, Robert D.

2015-05-01

Using a short pulse width x-ray source and measuring the time-of-flight of photons that scatter from an object under inspection allows for the point of interaction to be determined, and a profile of the object to be sampled along the path of the beam. A three dimensional image can be formed by interrogating the entire object. Using high energy x rays enables the inspection of cargo containers with steel walls, in the search for concealed items. A longer pulse width x-ray source can also be used with deconvolution techniques to determine the points of interaction. We present time-of-flight results from both short (picosecond) width and long (hundreds of nanoseconds) width x-ray sources, and show that the position of scatter can be localised with a resolution of 2 ns, equivalent to 30 cm, for a 3 cm thick plastic test object.

Investigating radiation induced damage processes with femtosecond x-ray pulses (Conference Presentation)

NASA Astrophysics Data System (ADS)

Song, Changyong

2017-05-01

Interest in high-resolution structure investigation has been zealous, especially with the advent of X-ray free electron lasers (XFELs). The intense and ultra-short X-ray laser pulses ( 10 GW) pave new routes to explore structures and dynamics of single macromolecules, functional nanomaterials and complex electronic materials. In the last several years, we have developed XFEL single-shot diffraction imaging by probing ultrafast phase changes directly. Pump-probe single-shot imaging was realized by synchronizing femtosecond (<10 fs in FWHM) X-ray laser (probe) with femtosecond (50 fs) IR laser (pump) at better than 1 ps resolution. Nanoparticles under intense fs-laser pulses were investigated with fs XFEL pulses to provide insight into the irreversible particle damage processes with nanoscale resolution. Research effort, introduced, aims to extend the current spatio-temporal resolution beyond the present limit. We expect this single-shot dynamic imaging to open new science opportunity with XFELs.

Generation of bright isolated attosecond soft X-ray pulses driven by multicycle midinfrared lasers

PubMed Central

Chen, Ming-Chang; Mancuso, Christopher; Hernández-García, Carlos; Dollar, Franklin; Galloway, Ben; Popmintchev, Dimitar; Huang, Pei-Chi; Walker, Barry; Plaja, Luis; Jaroń-Becker, Agnieszka A.; Becker, Andreas; Murnane, Margaret M.; Kapteyn, Henry C.; Popmintchev, Tenio

2014-01-01

High harmonic generation driven by femtosecond lasers makes it possible to capture the fastest dynamics in molecules and materials. However, to date the shortest subfemtosecond (attosecond, 10−18 s) pulses have been produced only in the extreme UV region of the spectrum below 100 eV, which limits the range of materials and molecular systems that can be explored. Here we experimentally demonstrate a remarkable convergence of physics: when midinfrared lasers are used to drive high harmonic generation, the conditions for optimal bright, soft X-ray generation naturally coincide with the generation of isolated attosecond pulses. The temporal window over which phase matching occurs shrinks rapidly with increasing driving laser wavelength, to the extent that bright isolated attosecond pulses are the norm for 2-µm driving lasers. Harnessing this realization, we experimentally demonstrate the generation of isolated soft X-ray attosecond pulses at photon energies up to 180 eV for the first time, to our knowledge, with a transform limit of 35 attoseconds (as), and a predicted linear chirp of 300 as. Most surprisingly, advanced theory shows that in contrast with as pulse generation in the extreme UV, long-duration, 10-cycle, driving laser pulses are required to generate isolated soft X-ray bursts efficiently, to mitigate group velocity walk-off between the laser and the X-ray fields that otherwise limit the conversion efficiency. Our work demonstrates a clear and straightforward approach for robustly generating bright isolated attosecond pulses of electromagnetic radiation throughout the soft X-ray region of the spectrum. PMID:24850866

Generation of bright isolated attosecond soft X-ray pulses driven by multicycle midinfrared lasers.

PubMed

Chen, Ming-Chang; Mancuso, Christopher; Hernández-García, Carlos; Dollar, Franklin; Galloway, Ben; Popmintchev, Dimitar; Huang, Pei-Chi; Walker, Barry; Plaja, Luis; Jaroń-Becker, Agnieszka A; Becker, Andreas; Murnane, Margaret M; Kapteyn, Henry C; Popmintchev, Tenio

2014-06-10

High harmonic generation driven by femtosecond lasers makes it possible to capture the fastest dynamics in molecules and materials. However, to date the shortest subfemtosecond (attosecond, 10(-18) s) pulses have been produced only in the extreme UV region of the spectrum below 100 eV, which limits the range of materials and molecular systems that can be explored. Here we experimentally demonstrate a remarkable convergence of physics: when midinfrared lasers are used to drive high harmonic generation, the conditions for optimal bright, soft X-ray generation naturally coincide with the generation of isolated attosecond pulses. The temporal window over which phase matching occurs shrinks rapidly with increasing driving laser wavelength, to the extent that bright isolated attosecond pulses are the norm for 2-µm driving lasers. Harnessing this realization, we experimentally demonstrate the generation of isolated soft X-ray attosecond pulses at photon energies up to 180 eV for the first time, to our knowledge, with a transform limit of 35 attoseconds (as), and a predicted linear chirp of 300 as. Most surprisingly, advanced theory shows that in contrast with as pulse generation in the extreme UV, long-duration, 10-cycle, driving laser pulses are required to generate isolated soft X-ray bursts efficiently, to mitigate group velocity walk-off between the laser and the X-ray fields that otherwise limit the conversion efficiency. Our work demonstrates a clear and straightforward approach for robustly generating bright isolated attosecond pulses of electromagnetic radiation throughout the soft X-ray region of the spectrum.

A0535+26 - Refined position measurement and new pulse period data

NASA Technical Reports Server (NTRS)

Li, F.; Clark, G. W.; Jernigan, J. G.; Rappaport, S.

1979-01-01

The hard, pulsing, transient X-ray source A0535+26 has been observed with SAS 3 on three occasions during 1977-1978. These observations have yielded a precise position measurement (20 arcsec error radius), which renders the identification of A0535+26 with the Be star HDE 245770 virtually certain. The pulse phase was tracked for about 9 days in April 1978 and clearly showed both first and second derivatives in the pulse period. An analysis of these timing data, combined with data from previous observations, leads to the following conclusions: (1) a significant fraction of the observed changes in pulse period is probably intrinsic to the compact X-ray star (e.g., accretion torques on a neutron star), and (2) conservative limits on binary orbital parameters tend to further confirm a long orbital period (at least about 20 days).

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

Pulsed x-ray sources for characterization of gated framing cameras

NASA Astrophysics Data System (ADS)

Filip, Catalin V.; Koch, Jeffrey A.; Freeman, Richard R.; King, James A.

2017-08-01

Gated X-ray framing cameras are used to measure important characteristics of inertial confinement fusion (ICF) implosions such as size and symmetry, with 50 ps time resolution in two dimensions. A pulsed source of hard (>8 keV) X-rays, would be a valuable calibration device, for example for gain-droop measurements of the variation in sensitivity of the gated strips. We have explored the requirements for such a source and a variety of options that could meet these requirements. We find that a small-size dense plasma focus machine could be a practical single-shot X-ray source for this application if timing uncertainties can be overcome.

Tamper to delay motion and decrease ionization of a sample during short pulse x-ray imaging

DOEpatents

London, Richard A [Orinda, CA; Szoke,; Abraham, Hau-Riege [Fremont, CA; Stefan P. , Chapman; Henry, N [Livermore, CA

2007-06-26

A system for x-ray imaging of a small sample comprising positioning a tamper so that it is operatively connected to the sample, directing short intense x-ray pulses onto the tamper and the sample, and detecting an image from the sample. The tamper delays the explosive motion of the sample during irradiation by the short intense x-ray pulses, thereby extending the time to obtain an x-ray image of the original structure of the sample.

Generation of bright attosecond x-ray pulse trains via Thomson scattering from laser-plasma accelerators.

PubMed

Luo, W; Yu, T P; Chen, M; Song, Y M; Zhu, Z C; Ma, Y Y; Zhuo, H B

2014-12-29

Generation of attosecond x-ray pulse attracts more and more attention within the advanced light source user community due to its potentially wide applications. Here we propose an all-optical scheme to generate bright, attosecond hard x-ray pulse trains by Thomson backscattering of similarly structured electron beams produced in a vacuum channel by a tightly focused laser pulse. Design parameters for a proof-of-concept experiment are presented and demonstrated by using a particle-in-cell code and a four-dimensional laser-Compton scattering simulation code to model both the laser-based electron acceleration and Thomson scattering processes. Trains of 200 attosecond duration hard x-ray pulses holding stable longitudinal spacing with photon energies approaching 50 keV and maximum achievable peak brightness up to 10²⁰ photons/s/mm²/mrad²/0.1%BW for each micro-bunch are observed. The suggested physical scheme for attosecond x-ray pulse trains generation may directly access the fastest time scales relevant to electron dynamics in atoms, molecules and materials.

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 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.

Enhanced water window x-ray emission from in situ formed carbon clusters irradiated by intense ultra-short laser pulses

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

Chakravarty, U.; Rao, B. S.; Arora, V.

Enhanced water window x-ray emission (23–44 Å) from carbon clusters, formed in situ using a pre-pulse, irradiated by intense (I > 10{sup 17} W/cm{sup 2}) ultra-short laser pulse, is demonstrated. An order of magnitude x-ray enhancement over planar graphite target is observed in carbon clusters, formed by a sub-ns pre-pulse, interacting with intense main pulse after a delay. The effect of the delay and the duration of the main pulse is studied for optimizing the x-ray emission in the water window region. This x-ray source has added advantages of being an efficient, high repetition rate, and low debris x-ray source.

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

NASA Technical Reports Server (NTRS)

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

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

NASA Technical Reports Server (NTRS)

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

2001-01-01

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

Numerical simulations of the hard X-ray pulse intensity distribution at the Linac Coherent Light Source

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

Pardini, Tom; Aquila, Andrew; Boutet, Sebastien

Numerical simulations of the current and future pulse intensity distributions at selected locations along the Far Experimental Hall, the hard X-ray section of the Linac Coherent Light Source (LCLS), are provided. Estimates are given for the pulse fluence, energy and size in and out of focus, taking into account effects due to the experimentally measured divergence of the X-ray beam, and measured figure errors of all X-ray optics in the beam path. Out-of-focus results are validated by comparison with experimental data. Previous work is expanded on, providing quantitatively correct predictions of the pulse intensity distribution. Numerical estimates in focus aremore » particularly important given that the latter cannot be measured with direct imaging techniques due to detector damage. Finally, novel numerical estimates of improvements to the pulse intensity distribution expected as part of the on-going upgrade of the LCLS X-ray transport system are provided. As a result, we suggest how the new generation of X-ray optics to be installed would outperform the old one, satisfying the tight requirements imposed by X-ray free-electron laser facilities.« less

Numerical simulations of the hard X-ray pulse intensity distribution at the Linac Coherent Light Source

DOE PAGES

Pardini, Tom; Aquila, Andrew; Boutet, Sebastien; ...

2017-06-15

Numerical simulations of the current and future pulse intensity distributions at selected locations along the Far Experimental Hall, the hard X-ray section of the Linac Coherent Light Source (LCLS), are provided. Estimates are given for the pulse fluence, energy and size in and out of focus, taking into account effects due to the experimentally measured divergence of the X-ray beam, and measured figure errors of all X-ray optics in the beam path. Out-of-focus results are validated by comparison with experimental data. Previous work is expanded on, providing quantitatively correct predictions of the pulse intensity distribution. Numerical estimates in focus aremore » particularly important given that the latter cannot be measured with direct imaging techniques due to detector damage. Finally, novel numerical estimates of improvements to the pulse intensity distribution expected as part of the on-going upgrade of the LCLS X-ray transport system are provided. As a result, we suggest how the new generation of X-ray optics to be installed would outperform the old one, satisfying the tight requirements imposed by X-ray free-electron laser facilities.« less

Deconvolving the temporal response of photoelectric x-ray detectors for the diagnosis of pulsed radiations

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

Zou, Shiyang; Song, Peng; Pei, Wenbing

2013-09-15

Based on the conjugate gradient method, a simple algorithm is presented for deconvolving the temporal response of photoelectric x-ray detectors (XRDs) to reconstruct the resolved time-dependent x-ray fluxes. With this algorithm, we have studied the impact of temporal response of XRD on the radiation diagnosis of hohlraum heated by a short intense laser pulse. It is found that the limiting temporal response of XRD not only postpones the rising edge and peak position of x-ray pulses but also smoothes the possible fluctuations of radiation fluxes. Without a proper consideration of the temporal response of XRD, the measured radiation flux canmore » be largely misinterpreted for radiation pulses of a hohlraum heated by short or shaped laser pulses.« less

Pulsed x-ray imaging of high-density objects using a ten picosecond high-intensity laser driver

NASA Astrophysics Data System (ADS)

Rusby, D. R.; Brenner, C. M.; Armstrong, C.; Wilson, L. A.; Clarke, R.; Alejo, A.; Ahmed, H.; Butler, N. M. H.; Haddock, D.; Higginson, A.; McClymont, A.; Mirfayzi, S. R.; Murphy, C.; Notley, M.; Oliver, P.; Allott, R.; Hernandez-Gomez, C.; Kar, S.; McKenna, P.; Neely, D.

2016-10-01

Point-like sources of X-rays that are pulsed (sub nanosecond), high energy (up to several MeV) and bright are very promising for industrial and security applications where imaging through large and dense objects is required. Highly penetrating X-rays can be produced by electrons that have been accelerated by a high intensity laser pulse incident onto a thin solid target. We have used a pulse length of 10ps to accelerate electrons to create a bright x-ray source. The bremsstrahlung temperature was measured for a laser intensity from 8.5-12×1018 W/cm2. These x-rays have sequentially been used to image high density materials using image plate and a pixelated scintillator system.

Hercules X-1: Pulsed gamma-rays detected above 150 GeV

NASA Technical Reports Server (NTRS)

Cawley, M. F.; Fegan, D. J.; Gibbs, K. G.; Gorham, P. W.; Kenny, S.; Lamb, R. C.; Liebing, D. F.; Porter, N. A.; Stenger, V. J.; Weekes, T. C.

1985-01-01

The 1.24 second binary pulsar Her X-1, first observed in X-rays in 1971 by UHURU has now been seen as a sporadic gamma ray source from 1 TeV up to at least 500 TeV. In addition, reprocessed optical and infrared pulses are seen from the companion star HZ Herculis. Thus measurements of the Her X-1/HZ Herculis system span 15 decades in energy, rivaling both the Crab pulsar and Cygnus X-3 in this respect for a discrete galactic source.

Experimental strategies for imaging bioparticles with femtosecond hard X-ray pulses

DOE Data Explorer

Daurer, Benedikt, J.

2016-12-09

Facilitating the very short and intense pulses from an X-ray laser for the purpose of imaging small bioparticles carries the potential for structure determination at atomic resolution without the need for crystallization. In this study, we explore experimental strategies for this idea based on data collected at the Linac Coherent Light Source from 40 nm virus particles injected into a hard X-ray beam.

Long pulse Soft X-ray Emission from Laser Generated Irradiated Gold Foils

NASA Astrophysics Data System (ADS)

Davis, Joshua; Frank, Yechiel; Raicher, Erez; Fraenkel, Moshe; Keiter, Paul; Klein, Sallee; Drake, R. P.; Shvarts, Dov

2016-10-01

Long pulse soft x-ray sources (SXS) allow for flexibility in high-energy-density experimental designs by providing a means of driving matter to the high temperatures needed, for example to study radiation waves in different materials. SXSs can be made by using lasers to heat a high-Z thin foil, which then acts as a quasi-blackbody emitter. Previous studies of the x-ray emission characteristics of gold foils have focused on laser pulses of 1ns or less. We performed experiments using a 6.0ns laser pulse with energy of 2kJ on the Omega-60 system to generate and characterize multi-ns laser heated Au foils of thicknesses between 0.5-2.0 μm. We measured the 2D spatial profile of the emission with a soft x-ray camera and the time history of the emission with the Dante photodiode array . Effective temperatures for the emission were then calculated using the Dante measurements. Discussion of experimental results and a comparison with 1-D Rad-Hydro NLTE simulations will be presented.

High-flux soft x-ray harmonic generation from ionization-shaped few-cycle laser pulses

PubMed Central

Brahms, Christian; Gregory, Andrew; Tisch, John W. G.; Marangos, Jon P.

2018-01-01

Laser-driven high-harmonic generation provides the only demonstrated route to generating stable, tabletop attosecond x-ray pulses but has low flux compared to other x-ray technologies. We show that high-harmonic generation can produce higher photon energies and flux by using higher laser intensities than are typical, strongly ionizing the medium and creating plasma that reshapes the driving laser field. We obtain high harmonics capable of supporting attosecond pulses up to photon energies of 600 eV and a photon flux inside the water window (284 to 540 eV) 10 times higher than previous attosecond sources. We demonstrate that operating in this regime is key for attosecond pulse generation in the x-ray range and will become increasingly important as harmonic generation moves to fields that drive even longer wavelengths. PMID:29756033

Generation of stable subfemtosecond hard x-ray pulses with optimized nonlinear bunch compression

DOE PAGES

Huang, Senlin; Ding, Yuantao; Huang, Zhirong; ...

2014-12-15

In this paper, we propose a simple scheme that leverages existing x-ray free-electron laser hardware to produce stable single-spike, subfemtosecond x-ray pulses. By optimizing a high-harmonic radio-frequency linearizer to achieve nonlinear compression of a low-charge (20 pC) electron beam, we obtain a sharp current profile possessing a few-femtosecond full width at half maximum temporal duration. A reverse undulator taper is applied to enable lasing only within the current spike, where longitudinal space charge forces induce an electron beam time-energy chirp. Simulations based on the Linac Coherent Light Source parameters show that stable single-spike x-ray pulses with a duration less thanmore » 200 attoseconds can be obtained.« less

A two-stage series diode for intense large-area moderate pulsed X rays production.

PubMed

Lai, Dingguo; Qiu, Mengtong; Xu, Qifu; Su, Zhaofeng; Li, Mo; Ren, Shuqing; Huang, Zhongliang

2017-01-01

This paper presents a method for moderate pulsed X rays produced by a series diode, which can be driven by high voltage pulse to generate intense large-area uniform sub-100-keV X rays. A two stage series diode was designed for Flash-II accelerator and experimentally investigated. A compact support system of floating converter/cathode was invented, the extra cathode is floating electrically and mechanically, by withdrawing three support pins several milliseconds before a diode electrical pulse. A double ring cathode was developed to improve the surface electric field and emission stability. The cathode radii and diode separation gap were optimized to enhance the uniformity of X rays and coincidence of the two diode voltages based on the simulation and theoretical calculation. The experimental results show that the two stage series diode can work stably under 700 kV and 300 kA, the average energy of X rays is 86 keV, and the dose is about 296 rad(Si) over 615 cm 2 area with uniformity 2:1 at 5 cm from the last converter. Compared with the single diode, the average X rays' energy reduces from 132 keV to 88 keV, and the proportion of sub-100-keV photons increases from 39% to 69%.

Accurate prediction of X-ray pulse properties from a free-electron laser using machine learning

DOE PAGES

Sanchez-Gonzalez, A.; Micaelli, P.; Olivier, C.; ...

2017-06-05

Free-electron lasers providing ultra-short high-brightness pulses of X-ray radiation have great potential for a wide impact on science, and are a critical element for unravelling the structural dynamics of matter. To fully harness this potential, we must accurately know the X-ray properties: intensity, spectrum and temporal profile. Owing to the inherent fluctuations in free-electron lasers, this mandates a full characterization of the properties for each and every pulse. While diagnostics of these properties exist, they are often invasive and many cannot operate at a high-repetition rate. Here, we present a technique for circumventing this limitation. Employing a machine learning strategy,more » we can accurately predict X-ray properties for every shot using only parameters that are easily recorded at high-repetition rate, by training a model on a small set of fully diagnosed pulses. Lastly, this opens the door to fully realizing the promise of next-generation high-repetition rate X-ray lasers.« less

Accurate prediction of X-ray pulse properties from a free-electron laser using machine learning

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

Sanchez-Gonzalez, A.; Micaelli, P.; Olivier, C.

Free-electron lasers providing ultra-short high-brightness pulses of X-ray radiation have great potential for a wide impact on science, and are a critical element for unravelling the structural dynamics of matter. To fully harness this potential, we must accurately know the X-ray properties: intensity, spectrum and temporal profile. Owing to the inherent fluctuations in free-electron lasers, this mandates a full characterization of the properties for each and every pulse. While diagnostics of these properties exist, they are often invasive and many cannot operate at a high-repetition rate. Here, we present a technique for circumventing this limitation. Employing a machine learning strategy,more » we can accurately predict X-ray properties for every shot using only parameters that are easily recorded at high-repetition rate, by training a model on a small set of fully diagnosed pulses. Lastly, this opens the door to fully realizing the promise of next-generation high-repetition rate X-ray lasers.« less

Distance Estimation for Eclipsing X-Ray Pulsars

NASA Astrophysics Data System (ADS)

Wilson, Robert E.; Paul, B.; Raichur, H.

2006-06-01

Recent interest in eclipsing binaries as distance indicators leads naturally into direct distance estimation for X-ray pulsars by combination of pulse arrival times, radial velocities, X-ray eclipse duration, and spectra. Optical light curves may help in some cases by measuring tides and irradiation, although dynamical tides in eccentric systems limit light curve usefulness. Pulse arrivals give an absolute scale and also orbit shape and orientation, which may be poorly known from radial velocities. For example, orbital eccentricity of 0.09 is known from Vela X1 pulse arrivals, although optical velocities are too noisy to measure eccentricity accurately. Combined pulse and optical velocity data give mass information. A lower limit to sin i from eclipse duration sets a lower limit to R2, and for the general eccentric case. A mass ratio sets lobe size and thus an upper limit to R2, so boxing R2 within a narrow range may be possible. T2 can be assessed from spectra so EB distance estimation can work if magnitude is known in one or more standard bands such as B or V. Realistic distance uncertainties are explored. In regard to new observations, Vela X-1 was observed by RXTE over about nine days in January 2005, including an eclipse of about 3.5 days. We extracted the light curves with time resolution 0.125 s. Spin period measurements by the Chi square criterion show Doppler variation with orbital phase and mean spin period 283.5 s. Pulse profiles of that period were averaged in sets of 10 at 138 phases. Cross correlation for the first 40 pulses show the expected Doppler arrival time variation. As the Vela X-1 pulse period is large compared to light travel time across the orbit, the pulses are already phase connected. Support is by U.S. National Science Foundation grant 0307561.

Observation of femtosecond X-ray interactions with matter using an X-ray–X-ray pump–probe scheme

PubMed Central

Inoue, Ichiro; Inubushi, Yuichi; Sato, Takahiro; Tono, Kensuke; Katayama, Tetsuo; Kameshima, Takashi; Ogawa, Kanade; Togashi, Tadashi; Owada, Shigeki; Amemiya, Yoshiyuki; Tanaka, Takashi; Hara, Toru

2016-01-01

Resolution in the X-ray structure determination of noncrystalline samples has been limited to several tens of nanometers, because deep X-ray irradiation required for enhanced resolution causes radiation damage to samples. However, theoretical studies predict that the femtosecond (fs) durations of X-ray free-electron laser (XFEL) pulses make it possible to record scattering signals before the initiation of X-ray damage processes; thus, an ultraintense X-ray beam can be used beyond the conventional limit of radiation dose. Here, we verify this scenario by directly observing femtosecond X-ray damage processes in diamond irradiated with extraordinarily intense (∼1019 W/cm2) XFEL pulses. An X-ray pump–probe diffraction scheme was developed in this study; tightly focused double–5-fs XFEL pulses with time separations ranging from sub-fs to 80 fs were used to excite (i.e., pump) the diamond and characterize (i.e., probe) the temporal changes of the crystalline structures through Bragg reflection. It was found that the pump and probe diffraction intensities remain almost constant for shorter time separations of the double pulse, whereas the probe diffraction intensities decreased after 20 fs following pump pulse irradiation due to the X-ray–induced atomic displacement. This result indicates that sub-10-fs XFEL pulses enable conductions of damageless structural determinations and supports the validity of the theoretical predictions of ultraintense X-ray–matter interactions. The X-ray pump–probe scheme demonstrated here would be effective for understanding ultraintense X-ray–matter interactions, which will greatly stimulate advanced XFEL applications, such as atomic structure determination of a single molecule and generation of exotic matters with high energy densities. PMID:26811449

PAL-XFEL soft X-ray scientific instruments and X-ray optics: First commissioning results

NASA Astrophysics Data System (ADS)

Park, Sang Han; Kim, Minseok; Min, Changi-Ki; Eom, Intae; Nam, Inhyuk; Lee, Heung-Soo; Kang, Heung-Sik; Kim, Hyeong-Do; Jang, Ho Young; Kim, Seonghan; Hwang, Sun-min; Park, Gi-Soo; Park, Jaehun; Koo, Tae-Yeong; Kwon, Soonnam

2018-05-01

We report an overview of soft X-ray scientific instruments and X-ray optics at the free electron laser (FEL) of the Pohang Accelerator Laboratory, with selected first-commissioning results. The FEL exhibited a pulse energy of 200 μJ/pulse, a pulse width of <50 fs full width at half maximum, and an energy bandwidth of 0.44% at a photon energy of 850 eV. Monochromator resolving power of 10 500 was achieved. The estimated total time resolution between optical laser and X-ray pulses was <270 fs. A resonant inelastic X-ray scattering spectrometer was set up; its commissioning results are also reported.

Intense Non-Linear Soft X-Ray Emission from a Hydride Target during Pulsed D Bombardment

NASA Astrophysics Data System (ADS)

Miley, George H.; Yang, Yang; Lipson, Andrei; Haque, Munima; Percel, Ian; Romer, Michael

Radiation emission from low-energy nuclear radiation (LENR) electrodes (both charged-particle and X-rays) represents an important feature of LENR in general. Here, calibration, measurement techniques, and soft X-ray emission results from deuterium bombardment of a Pd target (cathode) placed in a pulsed deuterium glow discharge (PGD) are described. An X-ray intensity of 13.4 mW/cm2 and a dose of 3.3 μJ/cm2 were calculated over a 0.5 ms pulse time from AXUV photodiode radiation detector measurements. A most striking feature is that X-ray energies >600 V are observed with a discharge voltage only about half of that value. To further investigate this phenomenon, emission during room temperature D-desorption from electrolytically loaded Pd:Dx cathodes was also studied. The X-ray emission energy observed was quite similar to the PGD case. However, the intensity in this case was almost 13 orders of magnitude lower due to the much lower deuterium fluxes involved.

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

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

Levine, Alan M.; Bradt, Hale V.; Chakrabarty, Deepto

2011-09-01

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

X-ray Free-electron Lasers

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

Feldhaus, J.; /DESY; Arthur, J.

In a free-electron laser (FEL) the lasing medium is a high-energy beam of electrons flying with relativistic speed through a periodic magnetic field. The interaction between the synchrotron radiation that is produced and the electrons in the beam induces a periodic bunching of the electrons, greatly increasing the intensity of radiation produced at a particular wavelength. Depending only on a phase match between the electron energy and the magnetic period, the wavelength of the FEL radiation can be continuously tuned within a wide spectral range. The FEL concept can be adapted to produce radiation wavelengths from millimeters to Angstroms, andmore » can in principle produce hard x-ray beams with unprecedented peak brightness, exceeding that of the brightest synchrotron source by ten orders of magnitude or more. This paper focuses on short-wavelength FELs. It reviews the physics and characteristic properties of single-pass FELs, as well as current technical developments aiming for fully coherent x-ray radiation pulses with pulse durations in the 100 fs to 100 as range. First experimental results at wavelengths around 100 nm and examples of scientific applications planned on the new, emerging x-ray FEL facilities are presented.« less

Radiation-Induced Chemical Dynamics in Ar Clusters Exposed to Strong X-Ray Pulses.

PubMed

Kumagai, Yoshiaki; Jurek, Zoltan; Xu, Weiqing; Fukuzawa, Hironobu; Motomura, Koji; Iablonskyi, Denys; Nagaya, Kiyonobu; Wada, Shin-Ichi; Mondal, Subhendu; Tachibana, Tetsuya; Ito, Yuta; Sakai, Tsukasa; Matsunami, Kenji; Nishiyama, Toshiyuki; Umemoto, Takayuki; Nicolas, Christophe; Miron, Catalin; Togashi, Tadashi; Ogawa, Kanade; Owada, Shigeki; Tono, Kensuke; Yabashi, Makina; Son, Sang-Kil; Ziaja, Beata; Santra, Robin; Ueda, Kiyoshi

2018-06-01

We show that electron and ion spectroscopy reveals the details of the oligomer formation in Ar clusters exposed to an x-ray free electron laser (XFEL) pulse, i.e., chemical dynamics triggered by x rays. With guidance from a dedicated molecular dynamics simulation tool, we find that van der Waals bonding, the oligomer formation mechanism, and charge transfer among the cluster constituents significantly affect ionization dynamics induced by an XFEL pulse of moderate fluence. Our results clearly demonstrate that XFEL pulses can be used not only to "damage and destroy" molecular assemblies but also to modify and transform their molecular structure. The accuracy of the predictions obtained makes it possible to apply the cluster spectroscopy, in connection with the respective simulations, for estimation of the XFEL pulse fluence in the fluence regime below single-atom multiple-photon absorption, which is hardly accessible with other diagnostic tools.

Radiation-Induced Chemical Dynamics in Ar Clusters Exposed to Strong X-Ray Pulses

NASA Astrophysics Data System (ADS)

Kumagai, Yoshiaki; Jurek, Zoltan; Xu, Weiqing; Fukuzawa, Hironobu; Motomura, Koji; Iablonskyi, Denys; Nagaya, Kiyonobu; Wada, Shin-ichi; Mondal, Subhendu; Tachibana, Tetsuya; Ito, Yuta; Sakai, Tsukasa; Matsunami, Kenji; Nishiyama, Toshiyuki; Umemoto, Takayuki; Nicolas, Christophe; Miron, Catalin; Togashi, Tadashi; Ogawa, Kanade; Owada, Shigeki; Tono, Kensuke; Yabashi, Makina; Son, Sang-Kil; Ziaja, Beata; Santra, Robin; Ueda, Kiyoshi

2018-06-01

We show that electron and ion spectroscopy reveals the details of the oligomer formation in Ar clusters exposed to an x-ray free electron laser (XFEL) pulse, i.e., chemical dynamics triggered by x rays. With guidance from a dedicated molecular dynamics simulation tool, we find that van der Waals bonding, the oligomer formation mechanism, and charge transfer among the cluster constituents significantly affect ionization dynamics induced by an XFEL pulse of moderate fluence. Our results clearly demonstrate that XFEL pulses can be used not only to "damage and destroy" molecular assemblies but also to modify and transform their molecular structure. The accuracy of the predictions obtained makes it possible to apply the cluster spectroscopy, in connection with the respective simulations, for estimation of the XFEL pulse fluence in the fluence regime below single-atom multiple-photon absorption, which is hardly accessible with other diagnostic tools.

A pulse shape discriminator and an online system for the balloon-borne hard X-ray/gamma-ray detector

NASA Astrophysics Data System (ADS)

Takahashi, T.; Kamae, T.; Tanaka, M.; Gunji, S.; Miyazuki, S.; Tamura, T.; Sekimoto, Y.; Yamaoka, N.; Nishimura, J.; Yajima, N.

Attention is given to a new kind of phoswich counters (the well-type phoswich counter) that will be capable of detecting very low flux hard X-rays/gamma-rays (40-1000 keV) from astronomical objects. A specially designed pulse-shape discriminator (PSD) selects hard X-rays/gamma-rays that has deposited energy only in the detection part. Sixty-four such counters are assembled into an array where each phoswich element acts as an active shield to the neighboring elements too. The ADCs, the TDCs, the hit-pattern latches, and the precision clock are read out by a VME-based online system, stored on an 8-mm video tape, and transmitted to the ground station. The design and performance of the pulse shape discriminator and the online system are described.

Generation of subterawatt-attosecond pulses in a soft x-ray free-electron laser

DOE PAGES

Huang, Senlin; Ding, Yuantao; Huang, Zhirong; ...

2016-08-15

Here, we propose a novel scheme to generate attosecond soft x rays in a self-seeded free-electron laser (FEL) suitable for enabling attosecond spectroscopic investigations. A time-energy chirped electron bunch with additional sinusoidal energy modulation is adopted to produce a short seed pulse through a self-seeding monochromator. This short seed pulse, together with high electron current spikes and a cascaded delay setup, enables a high-efficiency FEL with a fresh bunch scheme. Simulations show that using the Linac Coherent Light Source (LCLS) parameters, soft x-ray pulses with a FWHM of 260 attoseconds and a peak power of 0.5 TW can be obtained.more » This scheme also has the feature of providing a stable central wavelength determined by the self-seeding monochromator.« less

Electron and fluorescence spectra of a water molecule irradiated by an x-ray free-electron laser pulse

NASA Astrophysics Data System (ADS)

Schäfer, Julia M.; Inhester, Ludger; Son, Sang-Kil; Fink, Reinhold F.; Santra, Robin

2018-05-01

With the highly intense x-ray light generated by x-ray free-electron lasers (XFELs), molecular samples can be ionized many times in a single pulse. Here we report on a computational study of molecular spectroscopy at the high x-ray intensity provided by XFELs. Calculated photoelectron, Auger electron, and x-ray fluorescence spectra are presented for a single water molecule that reaches many electronic hole configurations through repeated ionization steps. The rich details shown in the spectra depend on the x-ray pulse parameters in a nonintuitive way. We discuss how the observed trends can be explained by the competition of microscopic electronic transition processes. A detailed comparison between spectra calculated within the independent-atom model and within the molecular-orbital framework highlights the chemical sensitivity of the spectral lines of multiple-hole configurations. Our results demonstrate how x-ray multiphoton ionization-related effects such as charge-rearrangement-enhanced x-ray ionization of molecules and frustrated absorption manifest themselves in the electron and fluorescence spectra.

X1908+075: An X-Ray Binary with a 4.4 Day Period

NASA Astrophysics Data System (ADS)

Wen, Linqing; Remillard, Ronald A.; Bradt, Hale V.

2000-04-01

X1908+075 is an optically unidentified and highly absorbed X-ray source that appeared in early surveys such as Uhuru, OSO 7, Ariel 5, HEAO-1, and the EXOSAT Galactic Plane Survey. These surveys measured a source intensity in the range 2-12 mcrab at 2-10 keV, and the position was localized to ~0.5d. We use the Rossi X-Ray Timing Explorer (RXTE) All-Sky Monitor (ASM) to confirm our expectation that a particular Einstein/IPC detection (1E 1908.4+0730) provides the correct position for X1908+075. The analysis of the coded mask shadows from the ASM for the position of 1E 1908.4+0730 yields a persistent intensity ~8 mcrab (1.5-12 keV) over a 3 yr interval beginning in 1996 February. Furthermore, we detect a period of 4.400+/-0.001 days with a false-alarm probability less than 10-7. The folded light curve is roughly sinusoidal, with an amplitude that is 26% of the mean flux. The X-ray period may be attributed to the scattering and absorption of X-rays through a stellar wind combined with the orbital motion in a binary system. We suggest that X1908+075 is an X-ray binary with a high-mass companion star.

A Study of Pulse Shape Evolution and X-Ray Reprocessing in Her X-1

NASA Technical Reports Server (NTRS)

Cushman, Paula P.

1998-01-01

This study focused on the pulse shape evolution and spectral properties of the X-ray binary Her X-1 with regard to the well known 35-day cycle of Her X-1. A follow-up set of RXTE observations has been conducted in RXTE AO-2 phase and the two observation sets are being analyzed together. We presented results of early analysis of pulse shape evolution in "Proceedings of the Fourth Compton Symposium". More advanced analysis was presented at the HEAD meeting in November, 1997 in Estes Park, Colorado. A related study of the 35-day cycle using RXTE/ASM data, which laid out the overall picture within which the more detailed PCA observations could be placed has also been conducted. The results of this study have been published. A pair of papers on the detailed pulse evolution and the spectral/color evolution are currently being prepared for publication. Some of the significant results of this study have been a confirmation of the detailed pulse profile changes at the end of the Main High state in HerX-1 first observed by GINGA, observations of the pulse evolution in several Short High states which agree with the pulse evolution pattern predicted using a disk occultation model, observation of a systematic lengthening of the eclipse egress during the Main High state of the 35-day phase and observation of a new type of extended eclipse ingress during which pulsations cease to observed during the Short High state.

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

NASA Astrophysics Data System (ADS)

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

2016-11-01

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

Overview of options for generating high-brightness attosecond x-ray pulses at free-electron lasers and applications at the European XFEL

NASA Astrophysics Data System (ADS)

Serkez, S.; Geloni, G.; Tomin, S.; Feng, G.; Gryzlova, E. V.; Grum-Grzhimailo, A. N.; Meyer, M.

2018-02-01

The generation of attosecond, highbrightness x-ray pulses is a matter of great interest given their applications in the study of ultra-fast processes. In recent years, the production of x-ray pulses of high brightness, both in the soft and in the hard x-ray range, has been enabled by x-ray free-electron lasers (XFELs). In contrast to conventional quantum lasers, XFELs are based on the use of an ultra-relativistic electron beam as gain medium. They often work in the self-amplified spontaneous emission (SASE) regime, which provides pulses of duration down to a few femtoseconds, composed of several longitudinal modes. In order to further decrease the duration of these pulses, special methods need to be implemented. In this paper we review available methods, with particular focus on the x-ray laser-enhanced attosecond pulse generation, which is one of the most promising techniques. We illustrate the method using the SASE3 soft x-ray undulator of the European XFEL facility as a case study, emphasizing the importance of high-repetition rate attosecond x-ray pulses. The expected attosecond-level radiation output is used for simulations of sequential ionization processes in atoms in the case of ionization in the soft x-ray regime, demonstrating the importance of this opportunity for the user community.

Characterization of short-pulse laser-produced x-rays for diagnosing magnetically driven cylindrical isentropic compression

NASA Astrophysics Data System (ADS)

Sawada, Hiroshi; Daykin, Tyler; Bauer, Bruno; Beg, Farhat

2017-10-01

We have developed an experimental platform to study material properties of magnetically compressed cylinder using a 1 MA pulsed power generator Zebra and a 50 TW subpicosecond short-pulse laser Leopard at the UNR's Nevada Terawatt Facility. According to a MHD simulation, strong magnetic fields generated by 100 ns rise time Zebra current can quasi-isentropically compress a material to the strongly coupled plasma regime. Taking advantage of the cylindrical geometry, a metal rod can be brought to higher pressures than that in the planar geometry. To diagnose the compressed rod with high precision x-ray measurements, an initial laser-only experiment was carried out to characterize laser-produced x-rays. Interaction of a high-intensity, short-pulse laser with solids produces broadband and monochromatic x-rays with photon energies high enough to probe dense metal rods. Bremsstrahlung was measured with Imaging plate-based filter stack spectrometers and monochromatic 8.0 keV Cu K-alpha was recorded with an absolutely calibrated Bragg crystal spectrometer. The broadband x-ray source was applied to radiography of thick metal objects and different filter materials were tested. The experimental results and a design of a coupled experiment will be presented.

Gas gun shock experiments with single-pulse x-ray phase contrast imaging and diffraction at the Advanced Photon Source

NASA Astrophysics Data System (ADS)

Luo, S. N.; Jensen, B. J.; Hooks, D. E.; Fezzaa, K.; Ramos, K. J.; Yeager, J. D.; Kwiatkowski, K.; Shimada, T.

2012-07-01

The highly transient nature of shock loading and pronounced microstructure effects on dynamic materials response call for in situ, temporally and spatially resolved, x-ray-based diagnostics. Third-generation synchrotron x-ray sources are advantageous for x-ray phase contrast imaging (PCI) and diffraction under dynamic loading, due to their high photon fluxes, high coherency, and high pulse repetition rates. The feasibility of bulk-scale gas gun shock experiments with dynamic x-ray PCI and diffraction measurements was investigated at the beamline 32ID-B of the Advanced Photon Source. The x-ray beam characteristics, experimental setup, x-ray diagnostics, and static and dynamic test results are described. We demonstrate ultrafast, multiframe, single-pulse PCI measurements with unprecedented temporal (<100 ps) and spatial (˜2 μm) resolutions for bulk-scale shock experiments, as well as single-pulse dynamic Laue diffraction. The results not only substantiate the potential of synchrotron-based experiments for addressing a variety of shock physics problems, but also allow us to identify the technical challenges related to image detection, x-ray source, and dynamic loading.

A bright attosecond x-ray pulse train generation in a double-laser-driven cone target

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

Hu, Li-Xiang; Yu, Tong-Pu, E-mail: tongpu@nudt.edu.cn; Shao, Fu-Qiu

By using full three-dimensional particle-in-cell and Monte Carlo simulations, we investigate the generation of a high-brightness attosecond x-ray pulse train in a double-laser-driven cone target. The scheme makes use of two lasers: the first high-intensity laser with a laser peak intensity 1.37 × 10{sup 20 }W/cm{sup 2} irradiates the cone and produces overdense attosecond electron bunches; the second counterpropagating weakly relativistic laser with a laser peak intensity 4.932 × 10{sup 17 }W/cm{sup 2} interacts with the produced electron bunches and a bright x-ray pulse train is generated by Thomson backscattering of the second laser off the attosecond electron bunches. It is shown that the photon fluxmore » rises by 5 times using the cone target as compared with a normal channel. Meanwhile, the x-ray peak brightness increases significantly from 1.4 × 10{sup 21}/(s mm{sup 2} mrad{sup 2} 0.1 keV) to 6.0 × 10{sup 21}/(s mm{sup 2} mrad{sup 2} 0.1 keV), which is much higher than that of the Thomson x-ray source generated from traditional accelerators. We also discuss the influence of the laser and target parameters on the x-ray pulse properties. This compact bright x-ray source may have diverse applications, e.g., the study of electric dynamics and harmonics emission in the atomic scale.« less

X-Ray Radiation Measurements With Photodiodes In Plasmas Generated By 1017 W/Cm2 Intensity Krf Excimer Laser Pulses

NASA Astrophysics Data System (ADS)

Rácz, E.; Földes, I. B.; Ryć, L.

2006-01-01

Experiments were carried out using a prepulse-free hybrid KrF excimer-dye laser system (700fs pulse duration, 248nm wavelength, 15mJ pulse energy). The intensity of the p-polarized, focused laser beam was 1.5ṡ1017 W/cm2. Vacuum ultraviolet (VUV) and x-rays from solid state laser plasmas were generated in the laser-plasma interaction of subpicosecond laser pulses of nonrelativistic laser intensities. An x-ray sensitive FLM photodiode (ITE, Warsaw) was used to detect x-rays between 1-19 keV in front of the targets. The diode was filtered by a 4μm Al foil. The dependence of the x-ray flux on laser intensity and the angular distribution of x-rays for aluminum and copper targets in the half space of the front side of the targets were investigated.

Calculation of x-ray scattering patterns from nanocrystals at high x-ray intensity

PubMed Central

Abdullah, Malik Muhammad; Jurek, Zoltan; Son, Sang-Kil; Santra, Robin

2016-01-01

We present a generalized method to describe the x-ray scattering intensity of the Bragg spots in a diffraction pattern from nanocrystals exposed to intense x-ray pulses. Our method involves the subdivision of a crystal into smaller units. In order to calculate the dynamics within every unit, we employ a Monte-Carlo-molecular dynamics-ab-initio hybrid framework using real space periodic boundary conditions. By combining all the units, we simulate the diffraction pattern of a crystal larger than the transverse x-ray beam profile, a situation commonly encountered in femtosecond nanocrystallography experiments with focused x-ray free-electron laser radiation. Radiation damage is not spatially uniform and depends on the fluence associated with each specific region inside the crystal. To investigate the effects of uniform and non-uniform fluence distribution, we have used two different spatial beam profiles, Gaussian and flattop. PMID:27478859

Rate equations for nitrogen molecules in ultrashort and intense x-ray pulses

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

Liu, Ji -Cai; Berrah, Nora; Cederbaum, Lorenz S.

Here, we study theoretically the quantum dynamics of nitrogen molecules (N2) exposed to intense and ultrafast x-rays at a wavelength ofmore » $$1.1\\;{\\rm{nm}}$$ ($$1100\\;{\\rm{eV}}$$ photon energy) from the Linac Coherent Light Source (LCLS) free electron laser. Molecular rate equations are derived to describe the intertwined photoionization, decay, and dissociation processes occurring for N2. This model complements our earlier phenomenological approaches, the single-atom, symmetric-sharing, and fragmentation-matrix models of 2012 (J. Chem. Phys. 136 214310). Our rate-equations are used to obtain the effective pulse energy at the sample and the time scale for the dissociation of the metastable dication $${{\\rm{N}}}_{2}^{2+}$$. This leads to a very good agreement between the theoretically and experimentally determined ion yields and, consequently, the average charge states. The effective pulse energy is found to decrease with shortening pulse duration. This variation together with a change in the molecular fragmentation pattern and frustrated absorption—an effect that reduces absorption of x-rays due to (double) core hole formation—are the causes for the drop of the average charge state with shortening LCLS pulse duration discovered previously.« less

Rate equations for nitrogen molecules in ultrashort and intense x-ray pulses

DOE PAGES

Liu, Ji -Cai; Berrah, Nora; Cederbaum, Lorenz S.; ...

2016-03-16

Here, we study theoretically the quantum dynamics of nitrogen molecules (N2) exposed to intense and ultrafast x-rays at a wavelength ofmore » $$1.1\\;{\\rm{nm}}$$ ($$1100\\;{\\rm{eV}}$$ photon energy) from the Linac Coherent Light Source (LCLS) free electron laser. Molecular rate equations are derived to describe the intertwined photoionization, decay, and dissociation processes occurring for N2. This model complements our earlier phenomenological approaches, the single-atom, symmetric-sharing, and fragmentation-matrix models of 2012 (J. Chem. Phys. 136 214310). Our rate-equations are used to obtain the effective pulse energy at the sample and the time scale for the dissociation of the metastable dication $${{\\rm{N}}}_{2}^{2+}$$. This leads to a very good agreement between the theoretically and experimentally determined ion yields and, consequently, the average charge states. The effective pulse energy is found to decrease with shortening pulse duration. This variation together with a change in the molecular fragmentation pattern and frustrated absorption—an effect that reduces absorption of x-rays due to (double) core hole formation—are the causes for the drop of the average charge state with shortening LCLS pulse duration discovered previously.« less

Construction of a magnetic bottle spectrometer and its application to pulse duration measurement of X-ray laser using a pump-probe method

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

Namba, S., E-mail: namba@hiroshima-u.ac.jp; Hasegawa, N.; Kishimoto, M.

To characterize the temporal evolution of ultrashort X-ray pulses emitted by laser plasmas using a pump-probe method, a magnetic bottle time-of-flight electron spectrometer is constructed. The design is determined by numerical calculations of a mirror magnetic field and of the electron trajectory in a flight tube. The performance of the spectrometer is characterized by measuring the electron spectra of xenon atoms irradiated with a laser-driven plasma X-ray pulse. In addition, two-color above-threshold ionization (ATI) experiment is conducted for measurement of the X-ray laser pulse duration, in which xenon atoms are simultaneously irradiated with an X-ray laser pump and an IRmore » laser probe. The correlation in the intensity of the sideband spectra of the 4d inner-shell photoelectrons and in the time delay of the two laser pulses yields an X-ray pulse width of 5.7 ps, in good agreement with the value obtained using an X-ray streak camera.« less

Characterisation of flash X-ray source generated by Kali-1000 Pulse Power System

NASA Astrophysics Data System (ADS)

Satyanarayana, N.; Durga Prasada Rao, A.; Mittal, K. C.

2016-02-01

The electron beam-driven Rod Pinch Diode (RPD) is presently fielded on KALI-1000 Pulse Power System at Bhabha Atomic Research Centre, Visakhapatnam and is a leading candidate for future flash X-ray radiographic sources. The diode is capable of producing less than 2-mm radiation spot sizes and greater than 350 milli rads of dose measured at 1 m from the X-ray source. KALI-1000 Pulse Power Source is capable of delivering up to 600 kV using a Tesla Transformer with Demineralized Insulated Transmission Line (DITL), the diode typically operates between 250-330 kV . Since the radiation dose has a power-law dependence on diode voltage, this limits the dose production on KALI-1000 system. Radiation dose with angular variation is measured using thermoluminescent detectors (TLD's) and the X-ray spot size is measured using pin hole arrangement with image plate (IP) to obtain the time-integrated source profile as well as a time-resolved spot diagnostic. An X-ray pinhole camera was used to pick out where the energetic e-beam connects to the anode. Ideally the diode should function such that the radiation is emitted from the tip. The camera was mounted perpendicular to the machine's axis to view the radiation from the tip. Comparison of the spot sizes of the X-ray sources obtained by the pin hole and rolled edge arrangements was carried and results obtained by both the techniques are with in ± 10% of the average values.

Generation of plasma X-ray sources via high repetition rate femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Baguckis, Artūras; Plukis, Artūras; Reklaitis, Jonas; Remeikis, Vidmantas; Giniūnas, Linas; Vengris, Mikas

2017-12-01

In this study, we present the development and characterization of Cu plasma X-ray source driven by 20 W average power high repetition rate femtosecond laser in ambient atmosphere environment. The peak Cu- Kα photon flux of 2.3 × 109 photons/s into full solid angle is demonstrated (with a process conversion efficiency of 10-7), using pulses with peak intensity of 4.65 × 1014 W/cm2. Such Cu- Kα flux is significantly larger than others found in comparable experiments, performed in air environment. The effects of resonance plasma absorption process, when optimized, are shown to increase measured flux by the factor of 2-3. The relationship between X-ray photon flux and plasma-driving pulse repetition rate is quasi-linear, suggesting that fluxes could further be increased to 1010 photons/s using even higher average powers of driving radiation. These results suggest that to fully utilize the potential of high repetition rate laser sources, novel target material delivery systems (for example, jet-based ones) are required. On the other hand, this study demonstrates that high energy lasers currently used for plasma X-ray sources can be conveniently and efficiently replaced by high average power and repetition rate laser radiation, as a way to increase the brightness of the generated X-rays.

Pulse-resolved intensity measurements at a hard X-ray FEL using semi-transparent diamond detectors

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

Roth, Thomas; Freund, Wolfgang; Boesenberg, Ulrike

Solid-state ionization chambers are presented based on thin diamond crystals that allow pulse-resolved intensity measurements at a hard X-ray free-electron laser (FEL), up to the 4.5 MHz repetition rate that will become available at the European XFEL. Due to the small X-ray absorption of diamond the thin detectors are semi-transparent which eases their use as non-invasive monitoring devices in the beam. FELs are characterized by strong pulse-to-pulse intensity fluctuations due to the self-amplified spontaneous emission (SASE) process and in many experiments it is mandatory to monitor the intensity of each individual pulse. Two diamond detectors with different electrode materials, berylliummore » and graphite, were tested as intensity monitors at the XCS endstation of the Linac Coherent Light Source (LCLS) using the pink SASE beam at 9 keV. The performance is compared with LCLS standard monitors that detect X-rays backscattered from thin SiN foils placed in the beam. In conclusion, the graphite detector can also be used as a beam position monitor although with rather coarse resolution.« less

Pulse-resolved intensity measurements at a hard X-ray FEL using semi-transparent diamond detectors

DOE PAGES

Roth, Thomas; Freund, Wolfgang; Boesenberg, Ulrike; ...

2018-01-01

Solid-state ionization chambers are presented based on thin diamond crystals that allow pulse-resolved intensity measurements at a hard X-ray free-electron laser (FEL), up to the 4.5 MHz repetition rate that will become available at the European XFEL. Due to the small X-ray absorption of diamond the thin detectors are semi-transparent which eases their use as non-invasive monitoring devices in the beam. FELs are characterized by strong pulse-to-pulse intensity fluctuations due to the self-amplified spontaneous emission (SASE) process and in many experiments it is mandatory to monitor the intensity of each individual pulse. Two diamond detectors with different electrode materials, berylliummore » and graphite, were tested as intensity monitors at the XCS endstation of the Linac Coherent Light Source (LCLS) using the pink SASE beam at 9 keV. The performance is compared with LCLS standard monitors that detect X-rays backscattered from thin SiN foils placed in the beam. In conclusion, the graphite detector can also be used as a beam position monitor although with rather coarse resolution.« less

XUV and x-ray elastic scattering of attosecond electromagnetic pulses on atoms

NASA Astrophysics Data System (ADS)

Rosmej, F. B.; Astapenko, V. A.; Lisitsa, V. S.

2017-12-01

Elastic scattering of electromagnetic pulses on atoms in XUV and soft x-ray ranges is considered for ultra-short pulses. The inclusion of the retardation term, non-dipole interaction and an efficient scattering tensor approximation allowed studying the scattering probability in dependence of the pulse duration for different carrier frequencies. Numerical calculations carried out for Mg, Al and Fe atoms demonstrate that the scattering probability is a highly nonlinear function of the pulse duration and has extrema for pulse carrier frequencies in the vicinity of the resonance-like features of the polarization charge spectrum. Closed expressions for the non-dipole correction and the angular dependence of the scattered radiation are obtained.

Discovery of X-ray pulsations in the Be/X-ray binary IGR J06074+2205

NASA Astrophysics Data System (ADS)

Reig, P.; Zezas, A.

2018-05-01

Context. IGR J06074+2205 is a poorly studied X-ray source with a Be star companion. It has been proposed to belong to the group of Be/X-ray binaries (BeXBs). In BeXBs, accretion onto the neutron star occurs via the transfer of material from the Be star's circumstellar disk. Thus, in the absence of the disk, no X-ray should be detected. Aims: The main goal of this work is to study the quiescent X-ray emission of IGR J06074+2205 during a disk-loss episode. Methods: We obtained light curves at different energy bands and a spectrum covering the energy range 0.4-12 keV. We used Fourier analysis to study the aperiodic variability and epoch folding methods to study the periodic variability. Model fitting to the energy spectrum allowed us to identify the possible physical processes that generated the X-rays. Results: We show that at the time of the XMM-Newton observation, the decretion disk around the Be star had vanished. Still, accretion appears as the source of energy that powers the high-energy radiation in IGR J06074+2205. We report the discovery of X-ray pulsations with a pulse period of 373.2 s and a pulse fraction of 50%. The 0.4-12 keV spectrum is well described by an absorbed power law and blackbody components with the best fitting parameters: NH = (6.2 ± 0.5) × 1021 cm-2, kTbb = 1.16 ± 0.03 keV, and Γ = 1.5 ± 0.1. The absorbed X-ray luminosity is LX = 1.4 × 1034 erg s-1 assuming a distance of 4.5 kpc. Conclusions: The detection of X-ray pulsations confirms the nature of IGR J06074+2205 as a BeXB. We discuss various scenarios to explain the quiescent X-ray emission of this pulsar. We rule out cooling of the neutron star surface and magnetospheric emission and conclude that accretion is the most likely scenario. The origin of the accreted material remains an open question.

X-Pinch And Its Applications In X-ray Radiograph

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

Zou Xiaobing; Wang Xinxin; Liu Rui

2009-07-07

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

Measurements of Cyclotron Features and Pulse Periods in the High-Mass X-Ray Binaries 4U 1538-522 and 4U 1907+09 with the International Gamma-Ray Astrophysics Laboratory

NASA Technical Reports Server (NTRS)

Hemphill, Paul B.; Rothschild, Richard E.; Caballero, Isabel; Pottschmidt, Katja; Kuhnel, Matthias; Furst, Felix; Wilms, Jorn

2013-01-01

We present a spectral and timing analysis of International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of two high-mass X-ray binaries, 4U 1538-522 and 4U 1907+09. Our timing measurements for 4U 1538-522 find the pulse period to have exhibited a spin-up trend until approximately 2009, after which there is evidence for a torque reversal, with the source beginning to spin down to the most recently measured period of 525.407 plus or minus 0.001 seconds. The most recent INTEGRAL observations of 4U 1907+09 are not found to yield statistically significant pulse periods due to the significantly lower flux from the source compared with 4U 1538-522. A spectral model consisting of a power-law continuum with an exponential cutoff and modified by two cyclotron resonance scattering features is found to fit both sources well, with the cyclotron scattering features detected at approximately 22 and approximately 49 kiloelectronvolts for 4U 1538-522 and at approximately 18 and approximately 36 kiloelectronvolts for 4U 1907+09. The spectral parameters of 4U 1538-522 are generally not found to vary significantly with flux and there is little to no variation across the torque reversal. Examining our results in conjunction with previous work, we find no evidence for a correlation between cyclotron line energy and luminosity for 4U 1538-522. 4U 1907+09 shows evidence for a positive correlation between cyclotron line energy and luminosity, which would make it the fourth, and lowest luminosity, cyclotron line source to exhibit this relationship.

Large-scale atomistic calculations of clusters in intense x-ray pulses

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

Ho, Phay J.; Knight, Chris

Here, we present the methodology of our recently developed Monte-Carlo/ Molecular-Dynamics method for studying the fundamental ultrafast dynamics induced by high-fluence, high-intensity x-ray free electron laser (XFEL) pulses in clusters. The quantum nature of the initiating ionization process is accounted for by a Monte Carlo method to calculate probabilities of electronic transitions, including photo absorption, inner-shell relaxation, photon scattering, electron collision and recombination dynamics, and thus track the transient electronic configurations explicitly. The freed electrons and ions are followed by classical particle trajectories using a molecular dynamics algorithm. These calculations reveal the surprising role of electron-ion recombination processes that leadmore » to the development of nonuniform spatial charge density profiles in x-ray excited clusters over femtosecond timescales. In the high-intensity limit, it is important to include the recombination dynamics in the calculated scattering response even for a 2- fs pulse. We also demonstrate that our numerical codes and algorithms can make e!cient use of the computational power of massively parallel supercomputers to investigate the intense-field dynamics in systems with increasing complexity and size at the ultrafast timescale and in non-linear x-ray interaction regimes. In particular, picosecond trajectories of XFEL clusters with attosecond time resolution containing millions of particles can be e!ciently computed on upwards of 262,144 processes.« less

Large-scale atomistic calculations of clusters in intense x-ray pulses

DOE PAGES

Ho, Phay J.; Knight, Chris

2017-04-28

Here, we present the methodology of our recently developed Monte-Carlo/ Molecular-Dynamics method for studying the fundamental ultrafast dynamics induced by high-fluence, high-intensity x-ray free electron laser (XFEL) pulses in clusters. The quantum nature of the initiating ionization process is accounted for by a Monte Carlo method to calculate probabilities of electronic transitions, including photo absorption, inner-shell relaxation, photon scattering, electron collision and recombination dynamics, and thus track the transient electronic configurations explicitly. The freed electrons and ions are followed by classical particle trajectories using a molecular dynamics algorithm. These calculations reveal the surprising role of electron-ion recombination processes that leadmore » to the development of nonuniform spatial charge density profiles in x-ray excited clusters over femtosecond timescales. In the high-intensity limit, it is important to include the recombination dynamics in the calculated scattering response even for a 2- fs pulse. We also demonstrate that our numerical codes and algorithms can make e!cient use of the computational power of massively parallel supercomputers to investigate the intense-field dynamics in systems with increasing complexity and size at the ultrafast timescale and in non-linear x-ray interaction regimes. In particular, picosecond trajectories of XFEL clusters with attosecond time resolution containing millions of particles can be e!ciently computed on upwards of 262,144 processes.« less

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

NASA Astrophysics Data System (ADS)

Mangles, Stuart P. D.

2012-05-01

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

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.

Femtosecond laser-electron x-ray source

DOEpatents

Hartemann, Frederic V.; Baldis, Hector A.; Barty, Chris P.; Gibson, David J.; Rupp, Bernhard

2004-04-20

A femtosecond laser-electron X-ray source. A high-brightness relativistic electron injector produces an electron beam pulse train. A system accelerates the electron beam pulse train. The femtosecond laser-electron X-ray source includes a high intra-cavity power, mode-locked laser and an x-ray optics system.

Numerical optimization of a picosecond pulse driven Ni-like Nb x-ray laser at 20.3 nm

NASA Astrophysics Data System (ADS)

Lu, X.; Zhong, J. Y.; Li, Y. J.; Zhang, J.

2003-07-01

Detailed simulations of a Ni-like Nb x-ray laser pumped by a nanosecond prepulse followed by a picosecond main pulse are presented. The atomic physics data are obtained using the Cowan code [R. D. Cowan, The Theory of Atomic Structure and Spectra (University of California Press, Berkeley, CA, 1981)]. The optimization calculations are performed in terms of the intensity of prepulse and the time delay between the prepulse and the main pulse. A high gain over 150 cm-1 is obtained for the optimized drive pulse configuration. The ray-tracing calculations suggest that the total pump energy for a saturated x-ray laser can be reduced to less than 1 J.

Long-term X-ray studies of Scorpius X-1. I - Search for binary periodicity

NASA Technical Reports Server (NTRS)

Holt, S. S.; Boldt, E. A.; Serlemitsos, P. J.; Kaluzienski, L. J.

1976-01-01

No evidence for modulation of the Sco X-1 intensity between 3 and 6 keV at the optical period of 0.787313 day is found during one year of quasi-continuous observation. Any persistent X-ray modulation at this period must be less than one percent.

Analyzing the effect of slotted foil on radiation pulse profile in a mode locked afterburner X-ray free electron laser

NASA Astrophysics Data System (ADS)

Kumar, Sandeep; Hur, Min Sup; Chung, Moses

2017-06-01

Extremely short X-ray pulses in the attosecond (as) range are important tools for ultrafast dynamics, high resolution microscopy, and nuclear dynamics study. In this paper, we numerically examine the generation of gigawatt (GW) mode-locked (ML) multichromatic X-rays using the parameters of the Pohang Accelerator Laboratory (PAL)-X-ray free electron laser (XFEL), the Korean XFEL. In this vein, we analyze the ML-FEL [Thompson and McNeil, Phys. Rev. Lett. 100, 203901 (2008)] and mode-locked afterburner (MLAB) FEL [Dunning et al., Phys. Rev. Lett. 110, 104801 (2013)] schemes on the hard X-ray beamline of the PAL-XFEL. Using the ML scheme, we numerically demonstrate a train of radiation pulses in the hard X-ray (photon energy ˜12.4 keV) with 3.5 GW power and 16 as full-width half maximum (FWHM) pulse duration. On the other hand, using the MLAB scheme, a train of radiation pulses with 3 GW power and 1 as FWHM (900 zs in RMS) pulse duration has been obtained at 12.4 keV photon energy. Both schemes generate broadband, discrete, and coherent spectrum compared to the XFEL's narrowband spectrum. Furthermore, the effect of slotted foil is also studied first time on the MLAB-FEL output. Numerical comparisons show that the temporal structure of the MLAB-FEL output can be improved significantly by the use of the slotted foil. Such short X-ray pulses at XFEL facilities will allow the studies of electron-nuclear and nuclear dynamics in atoms or molecules, and the broadband radiation will substantially improve the efficiency of the experimental techniques such as X-ray crystallography and spectroscopy, paving the way for outstanding progress in biology and material science.

Development of a Real-Time Pulse Processing Algorithm for TES-Based X-Ray Microcalorimeters

NASA Technical Reports Server (NTRS)

Tan, Hui; Hennig, Wolfgang; Warburton, William K.; Doriese, W. Bertrand; Kilbourne, Caroline A.

2011-01-01

We report here a real-time pulse processing algorithm for superconducting transition-edge sensor (TES) based x-ray microcalorimeters. TES-based. microca1orimeters offer ultra-high energy resolutions, but the small volume of each pixel requires that large arrays of identical microcalorimeter pixe1s be built to achieve sufficient detection efficiency. That in turn requires as much pulse processing as possible must be performed at the front end of readout electronics to avoid transferring large amounts of data to a host computer for post-processing. Therefore, a real-time pulse processing algorithm that not only can be implemented in the readout electronics but also achieve satisfactory energy resolutions is desired. We have developed an algorithm that can be easily implemented. in hardware. We then tested the algorithm offline using several data sets acquired with an 8 x 8 Goddard TES x-ray calorimeter array and 2x16 NIST time-division SQUID multiplexer. We obtained an average energy resolution of close to 3.0 eV at 6 keV for the multiplexed pixels while preserving over 99% of the events in the data sets.

Tunable X-ray source

DOEpatents

Boyce, James R [Williamsburg, VA

2011-02-08

A method for the production of X-ray bunches tunable in both time and energy level by generating multiple photon, X-ray, beams through the use of Thomson scattering. The method of the present invention simultaneously produces two X-ray pulses that are tunable in energy and/or time.

Orbital Parameters for the X-Ray Pulsar IGR J16393-4643

NASA Astrophysics Data System (ADS)

Thompson, Thomas W. J.; Tomsick, John A.; Rothschild, Richard E.; in't Zand, J. J. M.; Walter, Roland

2006-09-01

With recent and archival Rossi X-Ray Timing Explorer (RXTE) X-ray measurements of the heavily obscured X-ray pulsar IGR J16393-4643, we carried out a pulse timing analysis to determine the orbital parameters. Assuming a circular orbit, we phase-connected data spanning over 1.5 yr. The most likely orbital solution has a projected semimajor axis of 43+/-2 lt-s and an orbital period of 3.6875+/-0.0006 days. This implies a mass function of 6.5+/-1.1 Msolar and confirms that this INTEGRAL source is a high-mass X-ray binary (HMXB) system. By including eccentricity in the orbital model, we find e<0.25 at the 2 σ level. The 3.7 day orbital period and the previously known ~910 s pulse period place the system in the region of the Corbet diagram populated by supergiant wind accretors, and the low eccentricity is also consistent with this type of system. Finally, it should be noted that although the 3.7 day solution is the most likely one, we cannot completely rule out two other solutions with orbital periods of 50.2 and 8.1 days.

Pulse X-ray device for stereo imaging and few-projection tomography of explosive and fast processes

NASA Astrophysics Data System (ADS)

Palchikov, E. I.; Dolgikh, A. V.; Klypin, V. V.; Krasnikov, I. Y.; Ryabchun, A. M.

2017-10-01

This paper describes the operation principles and design features of the device for single pulse X-raying of explosive and high-speed processes, developed on the basis of a Tesla transformer with lumped secondary capacitor bank. The circuit with the lumped capacitor bank allows transferring a greater amount of energy to the discharge circuit as compared with the Marks-surge generator for more effective operation with remote X-ray tubes connected by coaxial cables. The device equipped with multiple X-ray tubes provides simultaneous X-raying of extended or spaced objects, stereo imaging, or few-projection tomography.

Periodicities in the high-mass X-ray binary system RXJ0146.9+6121/LSI+61°235

NASA Astrophysics Data System (ADS)

Sarty, Gordon E.; Kiss, László L.; Huziak, Richard; Catalan, Lionel J. J.; Luciuk, Diane; Crawford, Timothy R.; Lane, David J.; Pickard, Roger D.; Grzybowski, Thomas A.; Closas, Pere; Johnston, Helen; Balam, David; Wu, Kinwah

2009-01-01

The high-mass X-ray binary RXJ0146.9+6121, with optical counterpart LSI+61°235 (V831Cas), is an intriguing system on the outskirts of the open cluster NGC663. It contains the slowest Be type X-ray pulsar known with a pulse period of around 1400s and, primarily from the study of variation in the emission line profile of Hα, it is known to have a Be decretion disc with a one-armed density wave period of approximately 1240d. Here we present the results of an extensive photometric campaign, supplemented with optical spectroscopy, aimed at measuring short time-scale periodicities. We find three significant periodicities in the photometric data at, in order of statistical significance, 0.34, 0.67 and 0.10d. We give arguments to support the interpretation that the 0.34 and 0.10d periods could be due to stellar oscillations of the B-type primary star and that the 0.67d period is the spin period of the Be star with a spin axis inclination of 23+10-8 degrees. We measured a systemic velocity of -37.0 +/- 4.3kms-1 confirming that LSI+61°235 has a high probability of membership in the young cluster NGC663 from which the system's age can be estimated as 20-25Myr. From archival RXTE All Sky Monitor (ASM) data we further find `super' X-ray outbursts roughly every 450d. If these super outbursts are caused by the alignment of the compact star with the one-armed decretion disc enhancement, then the orbital period is approximately 330d.

Generation of High Brightness X-rays with the PLEIADES Thomson X-ray Source

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

Brown, W J; Anderson, S G; Barty, C P J

2003-05-28

The use of short laser pulses to generate high peak intensity, ultra-short x-ray pulses enables exciting new experimental capabilities, such as femtosecond pump-probe experiments used to temporally resolve material structural dynamics on atomic time scales. PLEIADES (Picosecond Laser Electron InterAction for Dynamic Evaluation of Structures) is a next generation Thomson scattering x-ray source being developed at Lawrence Livermore National Laboratory (LLNL). Ultra-fast picosecond x-rays (10-200 keV) are generated by colliding an energetic electron beam (20-100 MeV) with a high intensity, sub-ps, 800 nm laser pulse. The peak brightness of the source is expected to exceed 10{sup 20} photons/s/0.1% bandwidth/mm2/mrad2. Simulationsmore » of the electron beam production, transport, and final focus are presented. Electron beam measurements, including emittance and final focus spot size are also presented and compared to simulation results. Measurements of x-ray production are also reported and compared to theoretical calculations.« less

Fresh-slice multicolour X-ray free-electron lasers

DOE PAGES

Lutman, Alberto A.; Maxwell, Timothy J.; MacArthur, James P.; ...

2016-10-24

X-ray free-electron lasers (XFELs) provide femtosecond X-ray pulses with a narrow energy bandwidth and unprecedented brightness. Ultrafast physical and chemical dynamics, initiated with a site-specific X-ray pulse, can be explored using XFELs with a second ultrashort X-ray probe pulse. However, existing double-pulse schemes are complicated, difficult to customize or provide only low-intensity pulses. Here we present the novel fresh-slice technique for multicolour pulse production, wherein different temporal slices of an electron bunch lase to saturation in separate undulator sections. This method combines electron bunch tailoring from a passive wakefield device with trajectory control to provide multicolour pulses. The fresh-slice schememore » outperforms existing techniques at soft X-ray wavelengths. It produces femtosecond pulses with a power of tens of gigawatts and flexible colour separation. The pulse delay can be varied from temporal overlap to almost one picosecond. As a result, we also demonstrate the first three-colour XFEL and variably polarized two-colour pulses.« less

Characterization of New Hard X-ray Cataclysmic Variables

NASA Technical Reports Server (NTRS)

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

2012-01-01

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

Fabrication of 200 nanometer period centimeter area hard x-ray absorption gratings by multilayer deposition

PubMed Central

Lynch, S K; Liu, C; Morgan, N Y; Xiao, X; Gomella, A A; Mazilu, D; Bennett, E E; Assoufid, L; de Carlo, F; Wen, H

2012-01-01

We describe the design and fabrication trials of x-ray absorption gratings of 200 nm period and up to 100:1 depth-to-period ratios for full-field hard x-ray imaging applications. Hard x-ray phase-contrast imaging relies on gratings of ultra-small periods and sufficient depth to achieve high sensitivity. Current grating designs utilize lithographic processes to produce periodic vertical structures, where grating periods below 2.0 μm are difficult due to the extreme aspect ratios of the structures. In our design, multiple bilayers of x-ray transparent and opaque materials are deposited on a staircase substrate, and mostly on the floor surfaces of the steps only. When illuminated by an x-ray beam horizontally, the multilayer stack on each step functions as a micro-grating whose grating period is the thickness of a bilayer. The array of micro-gratings over the length of the staircase works as a single grating over a large area when continuity conditions are met. Since the layers can be nanometers thick and many microns wide, this design allows sub-micron grating periods and sufficient grating depth to modulate hard x-rays. We present the details of the fabrication process and diffraction profiles and contact radiography images showing successful intensity modulation of a 25 keV x-ray beam. PMID:23066175

Ultra-short wavelength x-ray system

DOEpatents

Umstadter, Donald [Ann Arbor, MI; He, Fei [Ann Arbor, MI; Lau, Yue-Ying [Potomac, MD

2008-01-22

A method and apparatus to generate a beam of coherent light including x-rays or XUV by colliding a high-intensity laser pulse with an electron beam that is accelerated by a synchronized laser pulse. Applications include x-ray and EUV lithography, protein structural analysis, plasma diagnostics, x-ray diffraction, crack analysis, non-destructive testing, surface science and ultrafast science.

Long-Term Time Variability in the X-Ray Pulse Shape of the Crab Nebula Pulsar

NASA Astrophysics Data System (ADS)

Fazio, Giovanni G.

2000-01-01

This is the final performance report for our grant 'Long-Term Time Variability in the X-Ray Pulse Shape of the Crab Nebula Pulsar.' In the first year of this grant, we received the 50,000-second ROSAT (German acronym for X-ray satellite) High Resolution Images (HRI) observation of the Crab Nebula pulsar. We used the data to create a 65-ms-resolution pulse profile and compared it to a similar pulse profile obtained in 1991. No statistically significant differences were found. These results were presented at the January 1998 meeting of the American Astronomical Society. Since then, we have performed more sensitive analyses to search for potential changes in the pulse profile shape between the two data sets. Again, no significant variability was found. In order to augment this long (six-year) baseline data set, we have analyzed archival observations of the Crab Nebula pulsar with the Rossi X-Ray Timing Explorer (RXTE). While these observations have shorter time baselines than the ROSAT data set, their higher signal-to-noise offers similar sensitivity to long-term variability. Again, no significant variations have been found, confirming our ROSAT results. This work was done in collaboration with Prof. Stephen Eikenberry, Cornell University. These analyses will be included in Cornell University graduate student Dae-Sik Moon's doctoral thesis.

The determination of the pulse pile-up reject (PUR) counting for X and gamma ray spectrometry

NASA Astrophysics Data System (ADS)

Karabıdak, S. M.; Kaya, S.

2017-02-01

The collection the charged particles produced by the incident radiation on a detector requires a time interval. If this time interval is not sufficiently short compared with the peaking time of the amplifier, a loss in the recovered signal amplitude occurs. Another major constraint on the throughput of modern x or gamma-ray spectrometers is the time required for the subsequent the pulse processing by the electronics. Two above-mentioned limitations are cause of counting losses resulting from the dead time and the pile-up. The pulse pile-up is a common problem in x and gamma ray radiation detection systems. The pulses pile-up in spectroscopic analysis can cause significant errors. Therefore, inhibition of these pulses is a vital step. A way to reduce errors due to the pulse pile-up is a pile-up inspection circuitry (PUR). Such a circuit rejects some of the pulse pile-up. Therefore, this circuit leads to counting losses. Determination of these counting losses is an important problem. In this work, a new method is suggested for the determination of the pulse pile-up reject.

Marked depression of time interval between fertilization period and hatching period following exposure to low-dose X-rays in zebrafish.

PubMed

Miyachi, Yukihisa; Kanao, Tomoko; Okamoto, Takehito

2003-10-01

In recent years there has been growing concern over the stimulating effects of very low-dose X-rays. Our laboratory had observed that zebrafish irradiated with low-dose X-rays tended to emerge earlier than sham controls. This observation led us to quantitatively examine the effects of low-dose X irradiation on a series of stages of development in the zebrafish. The embryos were fertilized simultaneously in vitro and incubated at an optimal temperature without crowding. Following exposure of the cleavage period (1.5 h after fertilization) to 0.025-Gy X-rays, the duration to hatching was slightly shorter than that of the sham controls. This tendency was increased when the X-ray exposure occurred during the blastula period (3.5 h). In these embryos, the duration to hatching decreased significantly by an average of 6 h sooner than for sham controls. No differences in duration to hatching were seen when irradiation was given during either the zygote period (45 min) or the segmentation period (12 h). On the contrary, upon exposure to 0.5-Gy X-rays during the blastula period, the duration to hatching increased significantly relative to that of sham controls. These results suggest that the radiation-induced early hatching effect is observed for low doses of X-rays.

Focusing X-ray free-electron laser pulses using Kirkpatrick-Baez mirrors at the NCI hutch of the PAL-XFEL.

PubMed

Kim, Jangwoo; Kim, Hyo Yun; Park, Jaehyun; Kim, Sangsoo; Kim, Sunam; Rah, Seungyu; Lim, Jun; Nam, Ki Hyun

2018-01-01

The Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL) is a recently commissioned X-ray free-electron laser (XFEL) facility that provides intense ultrashort X-ray pulses based on the self-amplified spontaneous emission process. The nano-crystallography and coherent imaging (NCI) hutch with forward-scattering geometry is located at the hard X-ray beamline of the PAL-XFEL and provides opportunities to perform serial femtosecond crystallography and coherent X-ray diffraction imaging. To produce intense high-density XFEL pulses at the interaction positions between the X-rays and various samples, a microfocusing Kirkpatrick-Baez (KB) mirror system that includes an ultra-precision manipulator has been developed. In this paper, the design of a KB mirror system that focuses the hard XFEL beam onto a fixed sample point of the NCI hutch, which is positioned along the hard XFEL beamline, is described. The focusing system produces a two-dimensional focusing beam at approximately 2 µm scale across the 2-11 keV photon energy range. XFEL pulses of 9.7 keV energy were successfully focused onto an area of size 1.94 µm × 2.08 µm FWHM.

Gain dynamics in a soft X-ray laser ampli er perturbed by a strong injected X-ray eld

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

Wang, Yong; Wang, Shoujun; Oliva, E

2014-01-01

Seeding soft X-ray plasma ampli ers with high harmonics has been demonstrated to generate high-brightness soft X-ray laser pulses with full spatial and temporal coherence. The interaction between the injected coherent eld and the swept-gain medium has been modelled. However, no exper- iment has been conducted to probe the gain dynamics when perturbed by a strong external seed eld. Here, we report the rst X-ray pump X-ray probe measurement of the nonlinear response of a plasma ampli er perturbed by a strong soft X-ray ultra-short pulse. We injected a sequence of two time-delayed high-harmonic pulses (l518.9 nm) into a collisionallymore » excited nickel-like molybdenum plasma to measure with femto-second resolution the gain depletion induced by the saturated ampli cation of the high-harmonic pump and its subsequent recovery. The measured fast gain recovery in 1.5 1.75 ps con rms the possibility to generate ultra-intense, fully phase-coherent soft X-ray lasers by chirped pulse ampli cation in plasma ampli ers.« less

The Peculiar X-ray Transient IGR 16358-4726

NASA Technical Reports Server (NTRS)

Patel, S. K.; Kouveliotou, C.; Tennant, A. F.; Woods, P. M.; King, A.; Ubertini, P.; Winkler, C.; Courvoisier, T.; VanDerKlis, M.; Wachter, S.

2003-01-01

The new transient IGR 16358-4726 was discovered on 2003 March 19 with INTEGRAL. We detected the source serendipitously during our 2003 March 24 observation of SGR 1627 - 4lwith the Chandra X-ray observatory at the 1.7 x 10(exp -l0) ergs/s sq cm flux level ( 2-10 keV) with a very high absorption column (N_H = 3.3 x 10(exp 23)/sq cm and a hard power law spectrum of index 0.5(1). We discovered a very strong flux modulation with a period of 5880(50) s and peak-to-peak pulse fraction of 70(6)% (2-10 keV), clearly visible in the X-ray data. The nature of IGR 16358-4726 remains unresolved. The only neutron star systems known with similar spin periods are low luminosity persistent wind-fed pulsars; if this is a spin period, this transient is a new kind of object. If this is an orbital period, then the system could be a compact Low Mass X-ray Binary (LMXB).

Correlations in Scattered X-Ray Laser Pulses Reveal Nanoscale Structural Features of Viruses

NASA Astrophysics Data System (ADS)

Kurta, Ruslan P.; Donatelli, Jeffrey J.; Yoon, Chun Hong; Berntsen, Peter; Bielecki, Johan; Daurer, Benedikt J.; DeMirci, Hasan; Fromme, Petra; Hantke, Max Felix; Maia, Filipe R. N. C.; Munke, Anna; Nettelblad, Carl; Pande, Kanupriya; Reddy, Hemanth K. N.; Sellberg, Jonas A.; Sierra, Raymond G.; Svenda, Martin; van der Schot, Gijs; Vartanyants, Ivan A.; Williams, Garth J.; Xavier, P. Lourdu; Aquila, Andrew; Zwart, Peter H.; Mancuso, Adrian P.

2017-10-01

We use extremely bright and ultrashort pulses from an x-ray free-electron laser (XFEL) to measure correlations in x rays scattered from individual bioparticles. This allows us to go beyond the traditional crystallography and single-particle imaging approaches for structure investigations. We employ angular correlations to recover the three-dimensional (3D) structure of nanoscale viruses from x-ray diffraction data measured at the Linac Coherent Light Source. Correlations provide us with a comprehensive structural fingerprint of a 3D virus, which we use both for model-based and ab initio structure recovery. The analyses reveal a clear indication that the structure of the viruses deviates from the expected perfect icosahedral symmetry. Our results anticipate exciting opportunities for XFEL studies of the structure and dynamics of nanoscale objects by means of angular correlations.

MEASUREMENTS OF CYCLOTRON FEATURES AND PULSE PERIODS IN THE HIGH-MASS X-RAY BINARIES 4U 1538–522 AND 4U 1907+09 WITH THE INTERNATIONAL GAMMA-RAY ASTROPHYSICS LABORATORY

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

Hemphill, Paul B.; Rothschild, Richard E.; Caballero, Isabel

We present a spectral and timing analysis of International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of two high-mass X-ray binaries, 4U 1538–522 and 4U 1907+09. Our timing measurements for 4U 1538–522 find the pulse period to have exhibited a spin-up trend until approximately 2009, after which there is evidence for a torque reversal, with the source beginning to spin down to the most recently measured period of 525.407 ± 0.001 s. The most recent INTEGRAL observations of 4U 1907+09 are not found to yield statistically significant pulse periods due to the significantly lower flux from the source compared with 4U 1538–522.more » A spectral model consisting of a power-law continuum with an exponential cutoff and modified by two cyclotron resonance scattering features is found to fit both sources well, with the cyclotron scattering features detected at ∼22 and ∼49 keV for 4U 1538–522 and at ∼18 and ∼36 keV for 4U 1907+09. The spectral parameters of 4U 1538–522 are generally not found to vary significantly with flux and there is little to no variation across the torque reversal. Examining our results in conjunction with previous work, we find no evidence for a correlation between cyclotron line energy and luminosity for 4U 1538–522. 4U 1907+09 shows evidence for a positive correlation between cyclotron line energy and luminosity, which would make it the fourth, and lowest luminosity, cyclotron line source to exhibit this relationship.« less

The Experimental Study of Characterized Noble Gas Puffs Irradiated by Ultra-Short Laser Pulses Compared with X-Pinches as an X-Ray Source

NASA Astrophysics Data System (ADS)

Schultz, Kimberly Ann

The goal of this dissertation is to study the basic physics and X-ray emission (1-10 keV) of two X-ray sources: X-pinch plasmas and a clustered gas-puff irradiated by an ultrashort laser pulse. X-pinches and other typical X-ray sources using solid targets create hot debris that can damage sensitive equipment. Therefore, to perform sensitive backlighting or X-ray effects testing, debris-free sources of radiation must be investigated. In this work, the author presents a broad study of clustered noble gas puffs including characterization measurements and laser heating experiments using several gas nozzles and multiple gases. Ultimately, the goal is to compare the laser-irradiated gas-puff and X-pinch plasmas as X-ray sources. Characterization of the gas puffs is performed at the Radiation Physics Laboratory at the University of Nevada, Reno (UNR) Physics Department using optical interferometry and Rayleigh scattering to determine density and cluster radius. By changing the gas-puff variables control of both the density and cluster size of the gas jets is obtained. Two laser systems provide the high intensities desired for the laser-irradiated gas puff experiments: the UNR Leopard Laser (1-2x1019 W/cm2) and the Lawrence Livermore National Laboratory's Titan Laser (7x1019 W/cm2). X-ray emission is studied as a function of laser pulse parameters, gas target type, gas puff density, and the gas-delay timing between puff initiation and laser interaction with the puff. The tested gases are Ar, Kr, Xe, and four mixtures of the noble gases. Time-resolved X-ray measurements are captured with Silicon diodes and photoconducting diamond detectors. Electron beam detectors include Faraday cups and a high-energy (> 1 MeV) electron spectrometer. Modeling of spectra from X-ray crystal spectrometers provides plasma density and temperature measurement and a molecular dynamics (MD) code describes cluster interactions with the laser pulse. The conversion of laser energy into X rays is also

Optimal generation of spatially coherent soft X-ray isolated attosecond pulses in a gas-filled waveguide using two-color synthesized laser pulses

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

Jin, Cheng; Hong, Kyung -Han; Lin, C. D.

2016-12-08

Here, we numerically demonstrate the generation of intense, low-divergence soft X-ray isolated attosecond pulses in a gas-filled hollow waveguide using synthesized few-cycle two-color laser waveforms. The waveform is a superposition of a fundamental and its second harmonic optimized such that highest harmonic yields are emitted from each atom. We then optimize the gas pressure and the length and radius of the waveguide such that bright coherent high-order harmonics with angular divergence smaller than 1 mrad are generated, for photon energy from the extreme ultraviolet to soft X-rays. By selecting a proper spectral range enhanced isolated attosecond pulses are generated. Wemore » study how dynamic phase matching caused by the interplay among waveguide mode, neutral atomic dispersion, and plasma effect is achieved at the optimal macroscopic conditions, by performing time-frequency analysis and by analyzing the evolution of the driving laser’s electric field during the propagation. Our results, when combined with the on-going push of high-repetition-rate lasers (sub- to few MHz’s) may eventually lead to the generation of high-flux, low-divergence soft X-ray tabletop isolated attosecond pulses for applications.« less

Thin film beam splitter multiple short pulse generation for enhanced Ni-like Ag x-ray laser emission.

PubMed

Cojocaru, Gabriel V; Ungureanu, Razvan G; Banici, Romeo A; Ursescu, Daniel; Delmas, Olivier; Pittman, Moana; Guilbaud, Olivier; Kazamias, Sophie; Cassou, Kevin; Demailly, Julien; Neveu, Olivier; Baynard, Elsa; Ros, David

2014-04-15

An alternative, novel multiple pulse generation scheme was implemented directly after the optical compressor output of an x-ray pump laser. The new method uses a polarization sensitive thin film beam splitter and a half-wavelength wave plate for tuning the energy ratio in the multiple short pulses. Based on this method, an extensive study was made of the running parameters for a grazing incidence pumped silver x-ray laser (XRL) pumped with a long pulse of 145 mJ in 6 ns at 532 nm and up to 1.45 J in few picoseconds at 810 nm. Fivefold enhancement in the emission of the silver XRL was demonstrated using the new pump method.

Specific features of thermocouple calorimeter application for measurements of pulsed X-ray emission from plasma

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

Gavrilov, V. V.; Fasakhov, I. K.

2012-01-15

It is shown that the accuracy of time-integrated measurements of pulsed X-ray emission from hot plasma with calibrated thermocouple calorimeters is mainly determined by two factors. The first and the most important factor is heating of the filter by the absorbed X-rays; as a result, the calorimeter measures the thermal radiation of the filter, which causes appreciable distortion of the temporal profile and amplitude of the recorded signal. The second factor is the dependence of the effective depth of X-ray absorption in the dielectric that covers the entrance window of the calorimeter on the energy of X-ray photons, i.e., onmore » the recorded radiation spectrum. The results of model calculations of the calorimeter signal are compared with the experimental data.« less

Correlations in Scattered X-Ray Laser Pulses Reveal Nanoscale Structural Features of Viruses

DOE PAGES

Kurta, Ruslan P.; Donatelli, Jeffrey J.; Yoon, Chun Hong; ...

2017-10-12

We use extremely bright and ultrashort pulses from an x-ray free-electron laser (XFEL) to measure correlations in x rays scattered from individual bioparticles. This allows us to go beyond the traditional crystallography and single-particle imaging approaches for structure investigations. We employ angular correlations to recover the three-dimensional (3D) structure of nanoscale viruses from x-ray diffraction data measured at the Linac Coherent Light Source. Correlations provide us with a comprehensive structural fingerprint of a 3D virus, which we use both for model-based and ab initio structure recovery. The analyses reveal a clear indication that the structure of the viruses deviates frommore » the expected perfect icosahedral symmetry. Lastly, our results anticipate exciting opportunities for XFEL studies of the structure and dynamics of nanoscale objects by means of angular correlations.« less

Infrared x-ray pump-probe spectroscopy of the NO molecule

NASA Astrophysics Data System (ADS)

Guimarães, F. F.; Kimberg, V.; Felicíssimo, V. C.; Gel'Mukhanov, F.; Cesar, A.; Ågren, H.

2005-07-01

Two color infrared x-ray pump-probe spectroscopy of the NO molecule is studied theoretically and numerically in order to obtain a deeper insight of the underlying physics and of the potential of this suggested technology. From the theoretical investigation a number of conclusions could be drawn: It is found that the phase of the infrared field strongly influences the trajectory of the nuclear wave packet, and hence, the x-ray spectrum. The trajectory experiences fast oscillations with the vibrational frequency with a modulation due to the anharmonicity of the potential. The dependences of the x-ray spectra on the delay time, the duration, and the shape of the pulses are studied in detail. It is shown that the x-ray spectrum keep memory about the infrared phase after the pump field left the system. This memory effect is sensitive to the time of switching-off the pump field and the Rabi frequency. The phase effect takes maximum value when the duration of the x-ray pulse is one-fourth of the infrared field period, and can be enhanced by a proper control of the duration and intensity of the pump pulse. The manifestation of the phase is different for oriented and disordered molecules and depends strongly on the intensity of the pump radiation.

Simultaneous, single-pulse, synchrotron x-ray imaging and diffraction under gas gun loading

DOE PAGES

Fan, D.; Huang, J. W.; Zeng, X. L.; ...

2016-05-23

We develop a mini gas gun system for simultaneous, single-pulse, x-ray diffraction and imaging under high strain-rate loading at the beamline 32-ID of the Advanced Photon Source. In order to increase the reciprocal space covered by a small-area detector, a conventional target chamber is split into two chambers: a narrowed measurement chamber and a relief chamber. The gas gun impact is synchronized with synchrotron x-ray pulses and high-speed cameras. Depending on a camera’s capability, multiframe imaging and diffraction can be achieved. The proof-of-principle experiments are performed on single-crystal sapphire. The diffraction spots and images during impact are analyzed to quantifymore » lattice deformation and fracture; diffraction peak broadening is largely caused by fracture-induced strain inhomogeneity. Finally, our results demonstrate the potential of such multiscale measurements for revealing and understanding high strain-rate phenomena at dynamic extremes.« less

Simultaneous, single-pulse, synchrotron x-ray imaging and diffraction under gas gun loading

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

Fan, D.; Luo, S. N., E-mail: sluo@pims.ac.cn; Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu, Sichuan 610031

We develop a mini gas gun system for simultaneous, single-pulse, x-ray diffraction and imaging under high strain-rate loading at the beamline 32-ID of the Advanced Photon Source. In order to increase the reciprocal space covered by a small-area detector, a conventional target chamber is split into two chambers: a narrowed measurement chamber and a relief chamber. The gas gun impact is synchronized with synchrotron x-ray pulses and high-speed cameras. Depending on a camera’s capability, multiframe imaging and diffraction can be achieved. The proof-of-principle experiments are performed on single-crystal sapphire. The diffraction spots and images during impact are analyzed to quantifymore » lattice deformation and fracture; fracture is dominated by splitting cracks followed by wing cracks, and diffraction peaks are broadened likely due to mosaic spread. Our results demonstrate the potential of such multiscale measurements for studying high strain-rate phenomena at dynamic extremes.« less

Simultaneous, single-pulse, synchrotron x-ray imaging and diffraction under gas gun loading

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

Fan, D.; Huang, J. W.; Zeng, X. L.

We develop a mini gas gun system for simultaneous, single-pulse, x-ray diffraction and imaging under high strain-rate loading at the beamline 32-ID of the Advanced Photon Source. In order to increase the reciprocal space covered by a small-area detector, a conventional target chamber is split into two chambers: a narrowed measurement chamber and a relief chamber. The gas gun impact is synchronized with synchrotron x-ray pulses and high-speed cameras. Depending on a camera’s capability, multiframe imaging and diffraction can be achieved. The proof-of-principle experiments are performed on single-crystal sapphire. The diffraction spots and images during impact are analyzed to quantifymore » lattice deformation and fracture; diffraction peak broadening is largely caused by fracture-induced strain inhomogeneity. Finally, our results demonstrate the potential of such multiscale measurements for revealing and understanding high strain-rate phenomena at dynamic extremes.« less

Microjet formation and hard x-ray production from a liquid metal target irradiated by intense femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Lar'kin, A.; Uryupina, D.; Ivanov, K.; Savel'ev, A.; Bonnet, T.; Gobet, F.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Spohr, K.; Breil, J.; Chimier, B.; Dorchies, F.; Fourment, C.; Leguay, P.-M.; Tikhonchuk, V. T.

2014-09-01

By using a liquid metal as a target one may significantly enhance the yield of hard x-rays with a sequence of two intense femtosecond laser pulses. The influence of the time delay between the two pulses is studied experimentally and interpreted with numerical simulations. It was suggested that the first arbitrary weak pulse produces microjets from the target surface, while the second intense pulse provides an efficient electron heating and acceleration along the jet surface. These energetic electrons are the source of x-ray emission while striking the target surface. The microjet formation is explained based on the results given by both optical diagnostics and hydrodynamic modeling by a collision of shocks originated from two distinct zones of laser energy deposition.

Searching for X-ray variability/periodicity in HD 4004.

NASA Astrophysics Data System (ADS)

Wessolowski, U.; Niedzielski, A.

1996-02-01

The authors present preliminary results of a combined X-ray and optical search for variability/periodicity in HD 4004 (WR 1, WN5-s), an apparently single Wolf-Rayet star known to show radial velocity variations (Lamontagne 1983) and some variability both in photometry (Moffat and Shara 1986) and in optical line profiles (Niedzielski 1995). The two ROSAT PSPC pointed observations of HD 4004 (total effective exposure time of 35 ks) do not provide significant evidence for variability in X-rays. Line profile variations present in newly obtained optical spectra are similar to those of EZ CMa (WR 6, WN5-s+c?), the banner WR+compact companion candidate.

Single mimivirus particles intercepted and imaged with an X-ray laser

PubMed Central

Seibert, M. Marvin; Ekeberg, Tomas; Maia, Filipe R. N. C.; Svenda, Martin; Andreasson, Jakob; Jönsson, Olof; Odić, Duško; Iwan, Bianca; Rocker, Andrea; Westphal, Daniel; Hantke, Max; DePonte, Daniel P.; Barty, Anton; Schulz, Joachim; Gumprecht, Lars; Coppola, Nicola; Aquila, Andrew; Liang, Mengning; White, Thomas A.; Martin, Andrew; Caleman, Carl; Stern, Stephan; Abergel, Chantal; Seltzer, Virginie; Claverie, Jean-Michel; Bostedt, Christoph; Bozek, John D.; Boutet, Sébastien; Miahnahri, A. Alan; Messerschmidt, Marc; Krzywinski, Jacek; Williams, Garth; Hodgson, Keith O.; Bogan, Michael J.; Hampton, Christina Y.; Sierra, Raymond G.; Starodub, Dmitri; Andersson, Inger; Bajt, Saša; Barthelmess, Miriam; Spence, John C. H.; Fromme, Petra; Weierstall, Uwe; Kirian, Richard; Hunter, Mark; Doak, R. Bruce; Marchesini, Stefano; Hau-Riege, Stefan P.; Frank, Matthias; Shoeman, Robert L.; Lomb, Lukas; Epp, Sascha W.; Hartmann, Robert; Rolles, Daniel; Rudenko, Artem; Schmidt, Carlo; Foucar, Lutz; Kimmel, Nils; Holl, Peter; Rudek, Benedikt; Erk, Benjamin; Hömke, André; Reich, Christian; Pietschner, Daniel; Weidenspointner, Georg; Strüder, Lothar; Hauser, Günter; Gorke, Hubert; Ullrich, Joachim; Schlichting, Ilme; Herrmann, Sven; Schaller, Gerhard; Schopper, Florian; Soltau, Heike; Kühnel, Kai-Uwe; Andritschke, Robert; Schröter, Claus-Dieter; Krasniqi, Faton; Bott, Mario; Schorb, Sebastian; Rupp, Daniela; Adolph, Marcus; Gorkhover, Tais; Hirsemann, Helmut; Potdevin, Guillaume; Graafsma, Heinz; Nilsson, Björn; Chapman, Henry N.; Hajdu, Janos

2014-01-01

X-ray lasers offer new capabilities in understanding the structure of biological systems, complex materials and matter under extreme conditions1–4. Very short and extremely bright, coherent X-ray pulses can be used to outrun key damage processes and obtain a single diffraction pattern from a large macromolecule, a virus or a cell before the sample explodes and turns into plasma1. The continuous diffraction pattern of non-crystalline objects permits oversampling and direct phase retrieval2. Here we show that high-quality diffraction data can be obtained with a single X-ray pulse from a non-crystalline biological sample, a single mimivirus particle, which was injected into the pulsed beam of a hard-X-ray free-electron laser, the Linac Coherent Light Source5. Calculations indicate that the energy deposited into the virus by the pulse heated the particle to over 100,000 K after the pulse had left the sample. The reconstructed exit wavefront (image) yielded 32-nm full-period resolution in a single exposure and showed no measurable damage. The reconstruction indicates inhomogeneous arrangement of dense material inside the virion. We expect that significantly higher resolutions will be achieved in such experiments with shorter and brighter photon pulses focused to a smaller area. The resolution in such experiments can be further extended for samples available in multiple identical copies. PMID:21293374

The UHURU X-ray instrument.

NASA Technical Reports Server (NTRS)

Jagoda, N.; Austin, G.; Mickiewicz, S.; Goddard, R.

1972-01-01

On Dec. 12, 1970, the UHURU X-ray observatory was launched into equatorial orbit with the prime mission of conducting an all-sky survey of astronomical X-ray sources with intensities of 0.00005 Sco-X1 or greater. The X-ray detection system contains 12 gas-filled proportional counters, 6 behind each collimator. The aspect system is discussed together with the structure, the pulse height analyzer, the command system, the calibration system, and the power distribution system. Pulse shape discrimination circuits used on UHURU use the same technique that was used on the system originally developed for large area proportional counters described by Gorenstein and Mickiewicz (1968).

Soft x ray properties of the Geminga pulsar

NASA Technical Reports Server (NTRS)

Halpern, J. P.; Ruderman, M.

1993-01-01

The ROSAT soft x ray spectrum and pulse profile of the Geminga pulsar are analyzed and interpreted in terms of thermal emission from the surface of the neutron star. The x ray spectrum appears to consist of two blackbody components with T(sub 1) = (5.2 +/- 1.0) x 10 (exp 5) K and T(sub 2) approximately 3 x 10(exp 6) K, respectively. The inferred ratio of surface areas, A(sub 2)/A(sub 1), is approximately 3 x 10(exp -5). Both components are highly modulated at the pulsar rotation period, but the harder x ray pulse is narrower, and leads the main (soft) x ray pulse by about 105 deg of phase. The soft x ray component is interpreted as photospheric cooling of much of the neutron star's surface area, while the small, hot region could be part of the much smaller polar cap heated by energetic particles flowing inward from the magnetospheric accelerator which is responsible for the production of Geminga's gamma rays. Geminga's gamma ray emission is consistent with outer-magnetosphere accelerator models for highly inclined dipoles. These predict the beaming of energetic gamma rays close enough to the star to give copious e(+/-) production in the stellar magnetic field and a large circumstellar pair density from pair inflow toward the surface. These pairs may quench radio emission, and also reflect most of the hard polar cap x rays back to the stellar surface by cyclotron resonance scattering. They are then reemitted from that much larger area at the lower temperature T(sub 1). The single-peaked nature of the x ray pulse and its energy-dependent phase suggest an off-center dipole geometry for the surface magnetic field. Under the assumption that the soft x ray emission comes from the full surface of a neutron star of radius R = 10 km, a distance estimate of (150-400) pc is derived. This range is consistent with the fit interstellar column density of (1.5 +/- 0.5) x 10(exp 20) cm(exp -2). Distances less than 150 pc are probably ruled out both by the lower limit on the column

Mode-Locked Multichromatic X-Rays in a Seeded Free-Electron Laser for Single-Shot X-Ray Spectroscopy

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

Xiang, Dao; Ding, Yuantao; Raubenheimer, Tor

2012-05-10

We present the promise of generating gigawatt mode-locked multichromatic x rays in a seeded free-electron laser (FEL). We show that, by using a laser to imprint periodic modulation in electron beam phase space, a single-frequency coherent seed can be amplified and further translated to a mode-locked multichromatic output in an FEL. With this configuration the FEL output consists of a train of mode-locked ultrashort pulses which span a wide frequency gap with a series of equally spaced sharp lines. These gigawatt multichromatic x rays may potentially allow one to explore the structure and dynamics of a large number of atomicmore » states simultaneously. The feasibility of generating mode-locked x rays ranging from carbon K edge ({approx}284 eV) to copper L{sub 3} edge ({approx}931 eV) is confirmed with numerical simulation using the realistic parameters of the linac coherent light source (LCLS) and LCLS-II. We anticipate that the mode-locked multichromatic x rays in FELs may open up new opportunities in x-ray spectroscopy (i.e. resonant inelastic x-ray scattering, time-resolved scattering and spectroscopy, etc.).« less

X-ray laser–induced electron dynamics observed by femtosecond diffraction from nanocrystals of Buckminsterfullerene

PubMed Central

Abbey, Brian; Dilanian, Ruben A.; Darmanin, Connie; Ryan, Rebecca A.; Putkunz, Corey T.; Martin, Andrew V.; Wood, David; Streltsov, Victor; Jones, Michael W. M.; Gaffney, Naylyn; Hofmann, Felix; Williams, Garth J.; Boutet, Sébastien; Messerschmidt, Marc; Seibert, M. Marvin; Williams, Sophie; Curwood, Evan; Balaur, Eugeniu; Peele, Andrew G.; Nugent, Keith A.; Quiney, Harry M.

2016-01-01

X-ray free-electron lasers (XFELs) deliver x-ray pulses with a coherent flux that is approximately eight orders of magnitude greater than that available from a modern third-generation synchrotron source. The power density of an XFEL pulse may be so high that it can modify the electronic properties of a sample on a femtosecond time scale. Exploration of the interaction of intense coherent x-ray pulses and matter is both of intrinsic scientific interest and of critical importance to the interpretation of experiments that probe the structures of materials using high-brightness femtosecond XFEL pulses. We report observations of the diffraction of extremely intense 32-fs nanofocused x-ray pulses by a powder sample of crystalline C60. We find that the diffraction pattern at the highest available incident power significantly differs from the one obtained using either third-generation synchrotron sources or XFEL sources operating at low output power and does not correspond to the diffraction pattern expected from any known phase of crystalline C60. We interpret these data as evidence of a long-range, coherent dynamic electronic distortion that is driven by the interaction of the periodic array of C60 molecular targets with intense x-ray pulses of femtosecond duration. PMID:27626076

Towards ultrafast dynamics with split-pulse X-ray photon correlation spectroscopy at free electron laser sources

DOE PAGES

Roseker, W.; Hruszkewycz, S. O.; Lehmkuhler, F.; ...

2018-04-27

One of the important challenges in condensed matter science is to understand ultrafast, atomic-scale fluctuations that dictate dynamic processes in equilibrium and non-equilibrium materials. Here, we report an important step towards reaching that goal by using a state-of-the-art perfect crystal based split-and-delay system, capable of splitting individual X-ray pulses and introducing femtosecond to nanosecond time delays. We show the results of an ultrafast hard X-ray photon correlation spectroscopy experiment at LCLS where split X-ray pulses were used to measure the dynamics of gold nanoparticles suspended in hexane. We show how reliable speckle contrast values can be extracted even from verymore » low intensity free electron laser (FEL) speckle patterns by applying maximum likelihood fitting, thus demonstrating the potential of a split-and-delay approach for dynamics measurements at FEL sources. This will enable the characterization of equilibrium and, importantly also reversible non-equilibrium processes in atomically disordered materials.« less

Towards ultrafast dynamics with split-pulse X-ray photon correlation spectroscopy at free electron laser sources

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

Roseker, W.; Hruszkewycz, S. O.; Lehmkuhler, F.

One of the important challenges in condensed matter science is to understand ultrafast, atomic-scale fluctuations that dictate dynamic processes in equilibrium and non-equilibrium materials. Here, we report an important step towards reaching that goal by using a state-of-the-art perfect crystal based split-and-delay system, capable of splitting individual X-ray pulses and introducing femtosecond to nanosecond time delays. We show the results of an ultrafast hard X-ray photon correlation spectroscopy experiment at LCLS where split X-ray pulses were used to measure the dynamics of gold nanoparticles suspended in hexane. We show how reliable speckle contrast values can be extracted even from verymore » low intensity free electron laser (FEL) speckle patterns by applying maximum likelihood fitting, thus demonstrating the potential of a split-and-delay approach for dynamics measurements at FEL sources. This will enable the characterization of equilibrium and, importantly also reversible non-equilibrium processes in atomically disordered materials.« less

Short Pulse High Brightness X-ray Production with the PLEIADES Thomson Scattering Source

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

Anderson, S G; Barty, C P J; Betts, S M

2003-07-01

We describe PLEIADES, a compact, tunable, high-brightness, ultra-short pulse, Thomson x-ray source. The peak brightness of the source is expected to exceed 10{sup 20} photons/s/0.1% bandwidth/mm{sup 2}/mrad{sup 2}. Initial results are reported and compared to theoretical calculations.

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.

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

High-rate x-ray spectroscopy in mammography with a CdTe detector: a digital pulse processing approach.

PubMed

Abbene, L; Gerardi, G; Principato, F; Del Sordo, S; Ienzi, R; Raso, G

2010-12-01

Direct measurement of mammographic x-ray spectra under clinical conditions is a difficult task due to the high fluence rate of the x-ray beams as well as the limits in the development of high resolution detection systems in a high counting rate environment. 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. The DPP system performs a digital pile-up inspection and a digital pulse height analysis of the detector signals, digitized through a 14-bit, 100 MHz digitizer, for x-ray spectroscopy even at high photon counting rates. We investigated on the response of the digital detection system both at low (150 cps) and at high photon counting rates (up to 500 kcps) by using monoenergetic x-ray sources and a nonclinical molybdenum anode x-ray tube. Clinical molybdenum x-ray spectrum measurements were also performed by using a pinhole collimator and a custom alignment device. The detection system shows excellent performance up to 512 kcps with an energy resolution of 4.08% FWHM at 22.1 keV. Despite the high photon counting rate (up to 453 kcps), the molybdenum x-ray spectra, measured under clinical conditions, are characterized by a low number of pile-up events. The agreement between the attenuation curves and the half value layer values, obtained from the measured spectra, simulated spectra, and from the exposure values directly measured with an ionization chamber, also shows the accuracy of the measurements. These results make the proposed detection system a very attractive tool for both laboratory research and advanced quality controls in mammography.

Burning plasmas with ultrashort soft-x-ray flashing

NASA Astrophysics Data System (ADS)

Hu, S. X.; Goncharov, V. N.; Skupsky, S.

2012-07-01

Fast ignition with narrow-band coherent x-ray pulses has been revisited for cryogenic deuterium-tritium (DT) plasma conditions achieved on the OMEGA Laser System. In contrast to using hard-x-rays (hv = 3-6 keV) proposed in the original x-ray fast-ignition proposal, we find that soft-x-ray sources with hv ≈ 500 eV photons can be suitable for igniting the dense DT-plasmas achieved on OMEGA. Two-dimensional radiation-hydrodynamics simulations have identified the break-even conditions for realizing such a "hybrid" ignition scheme (direct-drive compression with soft-x-ray heating) with 50-μm-offset targets: ˜10 ps soft-x-ray pulse (hv ≈ 500 eV) with a total energy of 500-1000 J to be focused into a 10 μm spot-size. A variety of x-ray pulse parameters have also been investigated for optimization. It is noted that an order of magnitude increase in neutron yield has been predicted even with x-ray energy as low as ˜50 J. Scaling this idea to a 1 MJ large-scale target, a gain above ˜30 can be reached with the same soft-x-ray pulse at 1.65 kJ energy. Even though such energetic x-ray sources do not currently exist, we hope that the proposed ignition scheme may stimulate efforts on generating powerful soft-x-ray sources in the near future.

Variable neutron star free precession in Hercules X-1 from evolution of RXTE X-ray pulse profiles with phase of the 35-d cycle

NASA Astrophysics Data System (ADS)

Postnov, K.; Shakura, N.; Staubert, R.; Kochetkova, A.; Klochkov, D.; Wilms, J.

2013-10-01

Accretion of matter on to the surface of a freely precessing neutron star (NS) with a complex non-dipole magnetic field can explain the change of X-ray pulse profiles of Her X-1 observed by RXTE with the phase of the 35-d cycle. We demonstrate this using all available measurements of X-ray pulse profiles in the 9-13 keV energy range obtained with the RXTE/Proportional Counter Array (PCA). The measured profiles guided the elaboration of a geometrical model and the definition of locations of emitting poles, arcs and spots on the NS surface which satisfactorily reproduce the observed pulse profiles and their dependence on free precession phase. We have found that the observed trend of the times of the 35-d turn-ons on the O-C diagram, which can be approximated by a collection of consecutive linear segments around the mean value, can be described by our model by assuming a variable free precession period, with a fractional period change of about a few per cent. Under this assumption and using our model, we have found that the times of phase zero of the NS free precession (which we identify with the maximum separation of the brightest spot on the NS surface with the NS spin axis) occur about 1.6 d after the mean turn-on times inside each `stable' epoch, producing a linear trend on the O-C diagram with the same slope as the observed times of turn-ons. We propose that the 2.5 per cent changes in the free precession period that occur on time scales of several to tens of 35-d cycles can be related to wandering of the principal inertia axis of the NS body due to variations in the patterns of accretion on to the NS surface. The closeness of periods of the disc precession and the NS free precession can be explained by the presence of a synchronization mechanism in the system, which modulates the dynamical interaction of the gas streams and the accretion disc with the NS free precession period.

Serendipitous Detections of XTE J1906+09 with the Rossi X-Ray Timing Explorer

NASA Technical Reports Server (NTRS)

Wilson, Colleen A.; Finger, Mark H.; Gogus, Ersin; Woods, Peter M.; Kouveliotou, Chryssa

2002-01-01

The 89 s X-ray pulsar XTE J1906+09 was discovered during Rossi X-Ray Timing Explorer (RXTE) observations of SGR 1900+14 in 1996. Because of monitoring campaigns of SGR 1900+14, XTE J1906+09 was also monitored regularly in 1996 September, 1998 May-June, 1998 August-1999 July, and 2000 March-2001 January. A search for pulsations resulted in detections of only the two previously reported outbursts in 1996 September and 1998 August-September. Pulsed flux upper limits for the rest of the observations show that XTE J1906+09 is a transient X-ray pulsar and likely has a Be star companion. The RXTE all-sky monitor did not reveal XTE J1906+09. Pulse-timing analysis of the second outburst discovered a sinusoidal signature in the pulse frequencies that is likely produced by an orbital periastron passage. Fits to pulse phases using an orbital model and quadratic phase model have chi(exp 2) minima at orbital periods of 26-30 days for fixed mass functions of 5, 10, 15, and 20 solar masses. The pulse shape showed energy- and intensity-dependent variations. Pulse-phase spectroscopy quantified the energy-dependent variations. The phase-averaged spectrum used the pulse minimum spectrum as the background spectrum to eliminate effects from SGR 1900+14 and the Galactic ridge and was well fitted by an absorbed power law with a high-energy cutoff with column density N(sub H) = 6 +/- 1 x 10(exp 22)/sq cm, a photon index of 1.01 +/- 0.08, cutoff energy E(sub cut) = 11 +/- 1 keV, and e-folding energy E(sub fold) = 19 +/- 4 keV. Estimated 2-10 keV peak fluxes, corrected for contributions from the Galactic ridge and SGR 1900+14, are 6 x l0(exp -12) and 1.1 x 10(exp -10) ergs/sq cm/s for the 1996 and 1998 outbursts, respectively. XTE J1906+09 may be part of an unusual class of Be/X-ray binaries that do not lie on the general spin period versus orbital period correlation with the majority of Be/X-ray binaries.

The high-energy pulsed X-ray spectrum of Hercules X-1 as observed with OSO 8

NASA Technical Reports Server (NTRS)

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

1979-01-01

Hercules X-1 was observed from August 30 to September 10, 1977, by using the high-energy X-ray scintillation spectrometer on board the OSO 8 satellite. The observation, during which the source was monitored continually for nearly an entire ON-state, covered the energy range from 16 to 280 keV. Pulsed-flux measurements as a function of binary orbit and binary phase are presented for energies between 16 and 98 keV. The pulsed flux between 16 and 33 keV exhibited a sharp decrease following the fourth binary orbit and was consistent with zero pulsed flux thereafter. Only weak evidence was found for temporal variation in the pulsed flux between 33 and 98 keV. The pulsed spectrum has been fitted with a power law, a thermal spectrum without features, and a thermal spectrum with a superposed Gaussian centered at 55 keV. The latter fit has the smallest value of chi-square per degree of freedom, and the resulting integrated line intensity is approximately 0.0015 photon/sec per sq cm for a width of 3.1 (+9.1, -2.6) keV. This result, while of low statistical significance, agrees with the value observed by Truemper (1978) during the same ON-state.

Simple Method to Generate Terawatt-Attosecond X-Ray Free-Electron-Laser Pulses.

PubMed

Prat, Eduard; Reiche, Sven

2015-06-19

X-ray free-electron lasers (XFELs) are cutting-edge research tools that produce almost fully coherent radiation with high power and short-pulse length with applications in multiple science fields. There is a strong demand to achieve even shorter pulses and higher radiation powers than the ones obtained at state-of-the-art XFEL facilities. In this context we propose a novel method to generate terawatt-attosecond XFEL pulses, where an XFEL pulse is pushed through several short good-beam regions of the electron bunch. In addition to the elements of conventional XFEL facilities, the method uses only a multiple-slotted foil and small electron delays between undulator sections. Our scheme is thus simple, compact, and easy to implement both in already operating as well as future XFEL projects. We present numerical simulations that confirm the feasibility and validity of our proposal.

Direct micromachining of quartz glass plates using pulsed laser plasma soft x-rays

NASA Astrophysics Data System (ADS)

Makimura, Tetsuya; Miyamoto, Hisao; Kenmotsu, Youichi; Murakami, Kouichi; Niino, Hiroyuki

2005-03-01

We have investigated direct micromachining of quartz glass, using pulsed laser plasma soft x-rays (LPSXs) having a potential capability of nanomachining because the diffraction limit is ˜10nm. The LPSX's were generated by irradiation of a Ta target with 532nm laser light from a conventional Q switched Nd :YAG laser at 700mJ/pulse. In order to achieve a sufficient power density of LPSX's beyond the ablation threshold, we developed an ellipsoidal mirror to obtain efficient focusing of LPSXs at around 10nm. It was found that quartz glass plates are smoothly ablated at 45nm/shot using the focused and pulsed LPSX's.

Nonlinear X-Ray and Auger Spectroscopy at X-Ray Free-Electron Laser Sources

NASA Astrophysics Data System (ADS)

Rohringer, Nina

2015-05-01

X-ray free-electron lasers (XFELs) open the pathway to transfer non-linear spectroscopic techniques to the x-ray domain. A promising all x-ray pump probe technique is based on coherent stimulated electronic x-ray Raman scattering, which was recently demonstrated in atomic neon. By tuning the XFEL pulse to core-excited resonances, a few seed photons in the spectral tail of the XFEL pulse drive an avalanche of resonant inelastic x-ray scattering events, resulting in exponential amplification of the scattering signal by of 6-7 orders of magnitude. Analysis of the line profile of the emitted radiation permits to demonstrate the cross over from amplified spontaneous emission to coherent stimulated resonance scattering. In combination with statistical covariance mapping, a high-resolution spectrum of the resonant inelastic scattering process can be obtained, opening the path to coherent stimulated x-ray Raman spectroscopy. An extension of these ideas to molecules and a realistic feasibility study of stimulated electronic x-ray Raman scattering in CO will be presented. Challenges to realizing stimulated electronic x-ray Raman scattering at present-day XFEL sources will be discussed, corroborated by results of a recent experiment at the LCLS XFEL. Due to the small gain cross section in molecular targets, other nonlinear spectroscopic techniques such as nonlinear Auger spectroscopy could become a powerful alternative. Theory predictions of a novel pump probe technique based on resonant nonlinear Auger spectroscopic will be discussed and the method will be compared to stimulated x-ray Raman spectroscopy.

Intensity correlation measurement system by picosecond single shot soft x-ray laser.

PubMed

Kishimoto, Maki; Namikawa, Kazumichi; Sukegawa, Kouta; Yamatani, Hiroshi; Hasegawa, Noboru; Tanaka, Momoko

2010-01-01

We developed a new soft x-ray speckle intensity correlation spectroscopy system by use of a single shot high brilliant plasma soft x-ray laser. The plasma soft x-ray laser is characterized by several picoseconds in pulse width, more than 90% special coherence, and 10(11) soft x-ray photons within a single pulse. We developed a Michelson type delay pulse generator using a soft x-ray beam splitter to measure the intensity correlation of x-ray speckles from materials and succeeded in generating double coherent x-ray pulses with picosecond delay times. Moreover, we employed a high-speed soft x-ray streak camera for the picosecond time-resolved measurement of x-ray speckles caused by double coherent x-ray pulse illumination. We performed the x-ray speckle intensity correlation measurements for probing the relaxation phenomena of polarizations in polarization clusters in the paraelectric phase of the ferroelectric material BaTiO(3) near its Curie temperature and verified its performance.

Table-top soft x-ray microscope using laser-induced plasma from a pulsed gas jet.

PubMed

Müller, Matthias; Mey, Tobias; Niemeyer, Jürgen; Mann, Klaus

2014-09-22

An extremely compact soft x-ray microscope operating in the "water window" region at the wavelength λ = 2.88 nm is presented, making use of a long-term stable and nearly debris-free laser-induced plasma from a pulsed nitrogen gas jet target. The well characterized soft x-ray radiation is focused by an ellipsoidal grazing incidence condenser mirror. Imaging of a sample onto a CCD camera is achieved with a Fresnel zone plate using magnifications up to 500x. The spatial resolution of the recorded microscopic images is about 100 nm as demonstrated for a Siemens star test pattern.

Application of MEMS-based x-ray optics as tuneable nanosecond choppers

NASA Astrophysics Data System (ADS)

Chen, Pice; Walko, Donald A.; Jung, Il Woong; Li, Zhilong; Gao, Ya; Shenoy, Gopal K.; Lopez, Daniel; Wang, Jin

2017-08-01

Time-resolved synchrotron x-ray measurements often rely on using a mechanical chopper to isolate a set of x-ray pulses. We have started the development of micro electromechanical systems (MEMS)-based x-ray optics, as an alternate method to manipulate x-ray beams. In the application of x-ray pulse isolation, we recently achieved a pulse-picking time window of half a nanosecond, which is more than 100 times faster than mechanical choppers can achieve. The MEMS device consists of a comb-drive silicon micromirror, designed for efficiently diffracting an x-ray beam during oscillation. The MEMS devices were operated in Bragg geometry and their oscillation was synchronized to x-ray pulses, with a frequency matching subharmonics of the cycling frequency of x-ray pulses. The microscale structure of the silicon mirror in terms of the curvature and the quality of crystallinity ensures a narrow angular spread of the Bragg reflection. With the discussion of factors determining the diffractive time window, this report showed our approaches to narrow down the time window to half a nanosecond. The short diffractive time window will allow us to select single x-ray pulse out of a train of pulses from synchrotron radiation facilities.

Anti-correlation between X-ray luminosity and pulsed fraction in the Small Magellanic Cloud pulsar SXP 1323

NASA Astrophysics Data System (ADS)

Yang, Jun; Zezas, Andreas; Coe, Malcolm J.; Drake, Jeremy J.; Hong, JaeSub; Laycock, Silas G. T.; Wik, Daniel R.

2018-05-01

We report the evidence for the anti-correlation between pulsed fraction (PF) and luminosity of the X-ray pulsar SXP 1323, found for the first time in a luminosity range 1035-1037 erg s-1 from observations spanning 15 years. The phenomenon of a decrease in X-ray PF when the source flux increases has been observed in our pipeline analysis of other X-ray pulsars in the Small Magellanic Cloud (SMC). It is expected that the luminosity under a certain value decreases as the PF decreases due to the propeller effect. Above the propeller region, an anti-correlation between the PF and flux might occur either as a result of an increase in the un-pulsed component of the total emission or a decrease of the pulsed component. Additional modes of accretion may also be possible, such as spherical accretion and a change in emission geometry. At higher mass accretion rates, the accretion disk could also extend closer to the neutron star (NS) surface, where a reduced inner radius leads to hotter inner disk emission. These modes of plasma accretion may affect the change in the beam configuration to fan-beam dominant emission.

A 4.2 Day Period in the X-ray Pulsar IGR J16393-4643 from Swift/BAT and RXTE/PCA Observations

NASA Astrophysics Data System (ADS)

Corbet, R. H. D.; Krimm, H. A.; Barthelmy, S. D.; Baumgartner, W. H.; Markwardt, C. B.; Skinner, G. K.; Tueller, J.

2010-04-01

The 910s X-ray pulsar IGR J16393-4643 was reported by Thompson et al. (2006, ApJ 649, 373) to have a 3.6875 ±0.0006 day orbital period from a pulse timing analysis, although other solutions with orbital periods of 50.2 and 8.1 days could not be excluded. Thompson et al. proposed, on the basis of their orbital parameters, that IGR J16393-4643 is a supergiant wind-accretion powered HMXB. Nespoli et al.

Terahertz pulsed imaging for the monitoring of dental caries: a comparison with x-ray imaging

NASA Astrophysics Data System (ADS)

Karagoz, Burcu; Kamburoglu, Kıvanc; Altan, Hakan

2017-07-01

Dental caries in sliced samples are investigated using terahertz pulsed imaging. Frequency domain terahertz response of these structures consistent with X-ray imaging results show the potential of this technique in the detection of early caries.

Proposed Laser-driven, Dielectric Microstructure Few-cm Long Undulator for Attosecond Coherent X-rays

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

Plettner, T; Byer, R.L.; /Stanford U., Ginzton Lab.

This article presents the concept of an all-dielectric laser-driven undulator for the generation of coherent X-rays. The proposed laser-driven undulator is expected to produce internal deflection forces equivalent to a several-Tesla magnetic field acting on a speed-of-light particle. The key idea for this laser-driven undulator is its ability to provide phase synchronicity between the deflection force and the electron beam for a distance that is much greater than the laser wavelength. The potential advantage of this undulator is illustrated with a possible design example that assumes a small laser accelerator which delivers a 2 GeV, 1 pC, 1 kHz electronmore » bunch train to a 10 cm long, 1/2 mm period laser-driven undulator. Such an undulator could produce coherent X-ray pulses with {approx}10{sup 9} photons of 64 keV energy. The numerical modeling for the expected X-ray pulse shape was performed with GENESIS, which predicts X-ray pulse durations in the few-attosecond range. Possible applications for nonlinear electromagnetic effects from these X-ray pulses are briefly discussed.« less

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.

Discovery of a 115 Day Orbital Period in the Ultraluminous X-ray Source NGC 5408 X-1

NASA Technical Reports Server (NTRS)

Strohmayer, Tod E.

2009-01-01

We report the detection of a 115 day periodicity in SWIFT/XRT monitoring data from the ultraluminous X-ray source (ULX) NGC 5408 X-1. Our o ngoing campaign samples its X-ray flux approximately twice weekly and has now achieved a temporal baseline of ti 485 days. Periodogram ana lysis reveals a significant periodicity with a period of 115.5 +/- 4 days. The modulation is detected with a significance of 3.2 x 10(exp -4) . The fractional modulation amplitude decreases with increasing e nergy, ranging from 0.13 +/- 0.02 above 1 keV to 0.24 +/- 0.02 below 1 keV. The shape of the profile evolves as well, becoming less sharply peaked at higher energies. The periodogram analysis is consistent wi th a periodic process, however, continued monitoring is required to c onfirm the coherent nature of the modulation. Spectral analysis indic ates that NGC 5408 X-1 can reach 0.3 - 10 keV luminosities of approxi mately 2 x 10 40 ergs/s . We suggest that, like the 62 day period of the ULX in M82 (X41.4-1-60), the periodicity detected in NGC 5408 X-1 represents the orbital period of the black hole binary containing the ULX. If this is true then the secondary can only be a giant or super giant star.

Ultrafast Dynamics of a Nucleobase Analogue Illuminated by a Short Intense X-ray Free Electron Laser Pulse

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

Nagaya, K.; Motomura, K.; Kukk, E.

Understanding x-ray radiation damage is a crucial issue for both medical applications of x rays and x-ray free-electron-laser (XFEL) science aimed at molecular imaging. Decrypting the charge and fragmentation dynamics of nucleobases, the smallest units of a macro-biomolecule, contributes to a bottom-up understanding of the damage via cascades of phenomena following x-ray exposure. We investigate experimentally and by numerical simulations the ultrafast radiation damage induced on a nucleobase analogue (5-iodouracil) by an ultrashort (10 fs) high-intensity radiation pulse generated by XFEL at SPring-8 Angstrom Compact free electron Laser (SACLA). The present study elucidates a plausible underlying radiosensitizing mechanism of 5-iodouracil.more » This mechanism is independent of the exact composition of 5-iodouracil and thus relevant to other such radiosensitizers. Furthermore, we found that despite a rapid increase of the net molecular charge in the presence of iodine, and of the ultrafast release of hydrogen, the other atoms are almost frozen within the 10-fs duration of the exposure. Finally, this validates single-shot molecular imaging as a consistent approach, provided the radiation pulse used is brief enough.« less

Ultrafast Dynamics of a Nucleobase Analogue Illuminated by a Short Intense X-ray Free Electron Laser Pulse

DOE PAGES

Nagaya, K.; Motomura, K.; Kukk, E.; ...

2016-06-16

Understanding x-ray radiation damage is a crucial issue for both medical applications of x rays and x-ray free-electron-laser (XFEL) science aimed at molecular imaging. Decrypting the charge and fragmentation dynamics of nucleobases, the smallest units of a macro-biomolecule, contributes to a bottom-up understanding of the damage via cascades of phenomena following x-ray exposure. We investigate experimentally and by numerical simulations the ultrafast radiation damage induced on a nucleobase analogue (5-iodouracil) by an ultrashort (10 fs) high-intensity radiation pulse generated by XFEL at SPring-8 Angstrom Compact free electron Laser (SACLA). The present study elucidates a plausible underlying radiosensitizing mechanism of 5-iodouracil.more » This mechanism is independent of the exact composition of 5-iodouracil and thus relevant to other such radiosensitizers. Furthermore, we found that despite a rapid increase of the net molecular charge in the presence of iodine, and of the ultrafast release of hydrogen, the other atoms are almost frozen within the 10-fs duration of the exposure. Finally, this validates single-shot molecular imaging as a consistent approach, provided the radiation pulse used is brief enough.« less

M.I.T. studies of transient X-ray phenomena. [astronomical observations

NASA Technical Reports Server (NTRS)

Canizares, C. R.

1976-01-01

A variety of transient X-ray phenomena have been studied. Data from the OSO-7 satellite reveal both long and short time-scale transients. Extensive observations have been made of the Lupus X-ray Nova (3U1543-47) and GX339-4(MX 1658-48) which may represent a very different type of transient source. A unique, intense X-ray flare lasting ten minutes was also recorded, and the X-ray emission from the active galaxy Cen A was found to vary significantly over a period of several days. In a recent balloon flight the Crab pulsar, NP0532, was observed to exhibit a transient pulsed component distinct from the usual main pulse and interpulse. A sounding-rocket experiment detected an ultrasoft transient X-ray source tentatively associated with SS Cygni, and preliminary results from SAS-3 show a very hard spectrum for the new source A0535 + 26. On the other hand, extensive OSO-7 null observations of both Type I and II supernovae and of the flaring radio star Algol make it unlikely that these types of objects are potent transient X-ray emitters.

ZAP! The X-Ray Laser is Born

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

Ratner, Daniel

2009-11-17

SLAC has converted its giant particle accelerator into the world's first X-ray laser. By a billion fold the world's brightest X-ray source, the laser packs a trillion photons into pulses as short as a millionth of a billionth of a second. The ultra-bright, ultra-short X-ray pulses will drive a wide range of new experiments, as scientists strip electrons from atoms, photograph single molecules and make movies of chemical reactions. How has SLAC accomplished such feats of X-ray wizardry? Attend this public lecture to learn about the basics of an X-ray laser, the technologies at SLAC that make it possible, andmore » the exciting new experiments now underway.« less

The impact of an ICME on the Jovian X-ray aurora.

PubMed

Dunn, William R; Branduardi-Raymont, Graziella; Elsner, Ronald F; Vogt, Marissa F; Lamy, Laurent; Ford, Peter G; Coates, Andrew J; Gladstone, G Randall; Jackman, Caitriona M; Nichols, Jonathan D; Rae, I Jonathan; Varsani, Ali; Kimura, Tomoki; Hansen, Kenneth C; Jasinski, Jamie M

2016-03-01

We report the first Jupiter X-ray observations planned to coincide with an interplanetary coronal mass ejection (ICME). At the predicted ICME arrival time, we observed a factor of ∼8 enhancement in Jupiter's X-ray aurora. Within 1.5 h of this enhancement, intense bursts of non-Io decametric radio emission occurred. Spatial, spectral, and temporal characteristics also varied between ICME arrival and another X-ray observation two days later. Gladstone et al. (2002) discovered the polar X-ray hot spot and found it pulsed with 45 min quasiperiodicity. During the ICME arrival, the hot spot expanded and exhibited two periods: 26 min periodicity from sulfur ions and 12 min periodicity from a mixture of carbon/sulfur and oxygen ions. After the ICME, the dominant period became 42 min. By comparing Vogt et al. (2011) Jovian mapping models with spectral analysis, we found that during ICME arrival at least two distinct ion populations, from Jupiter's dayside, produced the X-ray aurora. Auroras mapping to magnetospheric field lines between 50 and 70  R J were dominated by emission from precipitating sulfur ions (S 7+,…,14+ ). Emissions mapping to closed field lines between 70 and 120  R J and to open field lines were generated by a mixture of precipitating oxygen (O 7+,8+ ) and sulfur/carbon ions, possibly implying some solar wind precipitation. We suggest that the best explanation for the X-ray hot spot is pulsed dayside reconnection perturbing magnetospheric downward currents, as proposed by Bunce et al. (2004). The auroral enhancement has different spectral, spatial, and temporal characteristics to the hot spot. By analyzing these characteristics and coincident radio emissions, we propose that the enhancement is driven directly by the ICME through Jovian magnetosphere compression and/or a large-scale dayside reconnection event.

Start-to-end simulation of single-particle imaging using ultra-short pulses at the European X-ray Free-Electron Laser

DOE PAGES

Fortmann-Grote, Carsten; Buzmakov, Alexey; Jurek, Zoltan; ...

2017-09-01

Single-particle imaging with X-ray free-electron lasers (XFELs) has the potential to provide structural information at atomic resolution for non-crystalline biomolecules. This potential exists because ultra-short intense pulses can produce interpretable diffraction data notwithstanding radiation damage. This paper explores the impact of pulse duration on the interpretability of diffraction data using comprehensive and realistic simulations of an imaging experiment at the European X-ray Free-Electron Laser. In conclusion, it is found that the optimal pulse duration for molecules with a few thousand atoms at 5 keV lies between 3 and 9 fs.

Start-to-end simulation of single-particle imaging using ultra-short pulses at the European X-ray Free-Electron Laser

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

Fortmann-Grote, Carsten; Buzmakov, Alexey; Jurek, Zoltan

Single-particle imaging with X-ray free-electron lasers (XFELs) has the potential to provide structural information at atomic resolution for non-crystalline biomolecules. This potential exists because ultra-short intense pulses can produce interpretable diffraction data notwithstanding radiation damage. This paper explores the impact of pulse duration on the interpretability of diffraction data using comprehensive and realistic simulations of an imaging experiment at the European X-ray Free-Electron Laser. In conclusion, it is found that the optimal pulse duration for molecules with a few thousand atoms at 5 keV lies between 3 and 9 fs.

Start-to-end simulation of single-particle imaging using ultra-short pulses at the European X-ray Free-Electron Laser

PubMed Central

Buzmakov, Alexey; Jurek, Zoltan; Loh, Ne-Te Duane; Samoylova, Liubov; Santra, Robin; Schneidmiller, Evgeny A.; Tschentscher, Thomas; Yakubov, Sergey; Yoon, Chun Hong; Yurkov, Michael V.; Ziaja-Motyka, Beata; Mancuso, Adrian P.

2017-01-01

Single-particle imaging with X-ray free-electron lasers (XFELs) has the potential to provide structural information at atomic resolution for non-crystalline biomolecules. This potential exists because ultra-short intense pulses can produce interpretable diffraction data notwithstanding radiation damage. This paper explores the impact of pulse duration on the interpretability of diffraction data using comprehensive and realistic simulations of an imaging experiment at the European X-ray Free-Electron Laser. It is found that the optimal pulse duration for molecules with a few thousand atoms at 5 keV lies between 3 and 9 fs. PMID:28989713

Hetero-site-specific X-ray pump-probe spectroscopy for femtosecond intramolecular dynamics

PubMed Central

Picón, A.; Lehmann, C. S.; Bostedt, C.; Rudenko, A.; Marinelli, A.; Osipov, T.; Rolles, D.; Berrah, N.; Bomme, C.; Bucher, M.; Doumy, G.; Erk, B.; Ferguson, K. R.; Gorkhover, T.; Ho, P. J.; Kanter, E. P.; Krässig, B.; Krzywinski, J.; Lutman, A. A.; March, A. M.; Moonshiram, D.; Ray, D.; Young, L.; Pratt, S. T.; Southworth, S. H.

2016-01-01

New capabilities at X-ray free-electron laser facilities allow the generation of two-colour femtosecond X-ray pulses, opening the possibility of performing ultrafast studies of X-ray-induced phenomena. Particularly, the experimental realization of hetero-site-specific X-ray-pump/X-ray-probe spectroscopy is of special interest, in which an X-ray pump pulse is absorbed at one site within a molecule and an X-ray probe pulse follows the X-ray-induced dynamics at another site within the same molecule. Here we show experimental evidence of a hetero-site pump-probe signal. By using two-colour 10-fs X-ray pulses, we are able to observe the femtosecond time dependence for the formation of F ions during the fragmentation of XeF2 molecules following X-ray absorption at the Xe site. PMID:27212390

Hetero-site-specific X-ray pump-probe spectroscopy for femtosecond intramolecular dynamics

DOE PAGES

Picón, A.; Lehmann, C. S.; Bostedt, C.; ...

2016-05-23

New capabilities at X-ray free-electron laser facilities allow the generation of two-colour femtosecond X-ray pulses, opening the possibility of performing ultrafast studies of X-ray-induced phenomena. Specifically, the experimental realization of hetero-site-specific X-ray-pump/X-ray-probe spectroscopy is of special interest, in which an X-ray pump pulse is absorbed at one site within a molecule and an X-ray probe pulse follows the X-ray-induced dynamics at another site within the same molecule. In this paper, we show experimental evidence of a hetero-site pump-probe signal. By using two-colour 10-fs X-ray pulses, we are able to observe the femtosecond time dependence for the formation of F ionsmore » during the fragmentation of XeF 2 molecules following X-ray absorption at the Xe site.« less

Hetero-site-specific X-ray pump-probe spectroscopy for femtosecond intramolecular dynamics.

PubMed

Picón, A; Lehmann, C S; Bostedt, C; Rudenko, A; Marinelli, A; Osipov, T; Rolles, D; Berrah, N; Bomme, C; Bucher, M; Doumy, G; Erk, B; Ferguson, K R; Gorkhover, T; Ho, P J; Kanter, E P; Krässig, B; Krzywinski, J; Lutman, A A; March, A M; Moonshiram, D; Ray, D; Young, L; Pratt, S T; Southworth, S H

2016-05-23

New capabilities at X-ray free-electron laser facilities allow the generation of two-colour femtosecond X-ray pulses, opening the possibility of performing ultrafast studies of X-ray-induced phenomena. Particularly, the experimental realization of hetero-site-specific X-ray-pump/X-ray-probe spectroscopy is of special interest, in which an X-ray pump pulse is absorbed at one site within a molecule and an X-ray probe pulse follows the X-ray-induced dynamics at another site within the same molecule. Here we show experimental evidence of a hetero-site pump-probe signal. By using two-colour 10-fs X-ray pulses, we are able to observe the femtosecond time dependence for the formation of F ions during the fragmentation of XeF2 molecules following X-ray absorption at the Xe site.

STUDIES OF THE ORIGIN OF HIGH-FREQUENCY QUASI-PERIODIC OSCILLATIONS OF MASS-ACCRETING BLACK HOLES IN X-RAY BINARIES WITH NEXT-GENERATION X-RAY TELESCOPES

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

Beheshtipour, Banafsheh; Hoormann, Janie K.; Krawczynski, Henric, E-mail: b.beheshtipour@wustl.edu

Observations with RXTE ( Rossi X-ray Timing Explorer ) revealed the presence of high-frequency quasi-periodic oscillations (HFQPOs) of the X-ray flux from several accreting stellar-mass black holes. HFQPOs (and their counterparts at lower frequencies) may allow us to study general relativity in the regime of strong gravity. However, the observational evidence today does not yet allow us to distinguish between different HFQPO models. In this paper we use a general-relativistic ray-tracing code to investigate X-ray timing spectroscopy and polarization properties of HFQPOs in the orbiting Hotspot model. We study observational signatures for the particular case of the 166 Hz quasi-periodicmore » oscillation (QPO) in the galactic binary GRS 1915+105. We conclude with a discussion of the observability of spectral signatures with a timing-spectroscopy experiment such as the LOFT ( Large Observatory for X-ray Timing ) and polarization signatures with space-borne X-ray polarimeters such as IXPE ( Imaging X-ray Polarimetry Explorer ), PolSTAR ( Polarization Spectroscopic Telescope Array ), PRAXyS ( Polarimetry of Relativistic X-ray Sources ), or XIPE ( X-ray Imaging Polarimetry Explorer ). A mission with high count rate such as LOFT would make it possible to get a QPO phase for each photon, enabling the study of the QPO-phase-resolved spectral shape and the correlation between this and the flux level. Owing to the short periods of the HFQPOs, first-generation X-ray polarimeters would not be able to assign a QPO phase to each photon. The study of QPO-phase-resolved polarization energy spectra would thus require simultaneous observations with a first-generation X-ray polarimeter and a LOFT -type mission.« less

Exotic X-ray Sources from Intermediate Energy Electron Beams

NASA Astrophysics Data System (ADS)

Chouffani, K.; Wells, D.; Harmon, F.; Jones, J. L.; Lancaster, G.

2003-08-01

High intensity x-ray beams are used in a wide variety of applications in solid-state physics, medicine, biology and material sciences. Synchrotron radiation (SR) is currently the primary, high-quality x-ray source that satisfies both brilliance and tunability. The high cost, large size and low x-ray energies of SR facilities, however, are serious limitations. Alternatively, "novel" x-ray sources are now possible due to new small linear accelerator (LINAC) technology, such as improved beam emittance, low background, sub-Picosecond beam pulses, high beam stability and higher repetition rate. These sources all stem from processes that produce Radiation from relativistic Electron beams in (crystalline) Periodic Structures (REPS), or the periodic "structure" of laser light. REPS x-ray sources are serious candidates for bright, compact, portable, monochromatic, and tunable x-ray sources with varying degrees of polarization and coherence. Despite the discovery and early research into these sources over the past 25 years, these sources are still in their infancy. Experimental and theoretical research are still urgently needed to answer fundamental questions about the practical and ultimate limits of their brightness, mono-chromaticity etc. We present experimental results and theoretical comparisons for three exotic REPS sources. These are Laser-Compton Scattering (LCS), Channeling Radiation (CR) and Parametric X-Radiation (PXR).

Periodicities in the X-ray Emission from the Solar Corona: SphinX and SOXS Observations

NASA Astrophysics Data System (ADS)

Steślicki, M.; Awasthi, A. K.; Gryciuk, M.; Jain, R.

The structure and evolution of the solar magnetic field is driven by a magnetohydrodynamic dynamo operating in the solar interior, which induces various solar activities that exhibit periodic variations on different timescales. Therefore, probing the periodic nature of emission originating from the solar corona may provide insights of the convection-zone-photosphere-corona coupling processes. We present the study of the mid-range periodicities, between rotation period (˜27 days) and the Schwabe cycle period (˜11 yr), in the solar soft X-ray emission, based on the data obtained by two instruments: SphinX and SOXS in various energy bands.

Generation of sub-two-cycle millijoule infrared pulses in an optical parametric chirped-pulse amplifier and their application to soft x-ray absorption spectroscopy with high-flux high harmonics

NASA Astrophysics Data System (ADS)

Ishii, Nobuhisa; Kaneshima, Keisuke; Kanai, Teruto; Watanabe, Shuntaro; Itatani, Jiro

2018-01-01

An optical parametric chirped-pulse amplifier (OPCPA) based on bismuth triborate (BiB3O6, BIBO) crystals has been developed to deliver 1.5 mJ, 10.1 fs optical pulses around 1.6 μm with a repetition rate of 1 kHz and a stable carrier-envelope phase. The seed and pump pulses of the BIBO-based OPCPA are provided from two Ti:sapphire chirped-pulse amplification (CPA) systems. In both CPA systems, transmission gratings are used in the stretchers and compressors that result in a high throughput and robust operation without causing any thermal problem and optical damage. The seed pulses of the OPCPA are generated by intrapulse frequency mixing of a spectrally broadened continuum, temporally stretched to approximately 5 ps then, and amplified to more than 1.5 mJ. The amplified pulses are compressed in a fused silica block down to 10.1 fs. This BIBO-based OPCPA has been applied to high-flux high harmonic generation beyond the carbon K edge at 284 eV. The high-flux soft-x-ray continuum allows measuring the x-ray absorption near-edge structure of the carbon K edge within 2 min, which is shorter than a typical measurement time using synchrotron-based light sources. This laser-based table-top soft-x-ray source is a promising candidate for ultrafast soft x-ray spectroscopy with femtosecond to attosecond time resolution.

BioCARS: a synchrotron resource for time-resolved X-ray science

PubMed Central

Graber, T.; Anderson, S.; Brewer, H.; Chen, Y.-S.; Cho, H. S.; Dashdorj, N.; Henning, R. W.; Kosheleva, I.; Macha, G.; Meron, M.; Pahl, R.; Ren, Z.; Ruan, S.; Schotte, F.; Šrajer, V.; Viccaro, P. J.; Westferro, F.; Anfinrud, P.; Moffat, K.

2011-01-01

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 beam to a spot size of 90 µm horizontal by 20 µm 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 ∼4 × 1010 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. PMID:21685684

Improving the efficiency of x-ray lasers

NASA Astrophysics Data System (ADS)

Tallents, Gregory J.; Zeitoun, Philippe; Behjat, A.; Demir, A.; Holden, M.; Krishnan, J.; Lewis, Ciaran L. S.; MacPhee, Andrew G.; Warwick, P. J.; Nantel, Marc; Jamelot, Gerard; Rus, Bedrich; Jaegle, Pierre; Klisnick, Annie; Goedtkindt, P.; Carillon, Antoine; Fill, Ernst E.; Li, Yuelin; Pretzler, Georg; Schloegl, Dieter; Steingruber, Juergen; Neely, David; Norreys, Peter A.; Key, Michael H.; Zhang, Jie; Pert, Geoffrey J.; Healy, S. B.; Plowes, J. A.

1995-09-01

Current successful approaches for achieving soft x-ray lasing typically require pumping laser pulses of duration approximately ns and energy approximately kJ (collisionally pumped schemes) or approximately ps pulses and powers of approximately several TW (recombination-pumped schemes). For applications, it is important to improve the efficiency of soft x-ray lasers and so reduce the required power of pumping lasers. The effect of pre- pulse on neon-like collisionally pumped lasers has been investigated using the LULI laser (Ecole Polytechnique, France). A small pre-pulse level approximately 10-3 of the main pulse energy was found to increase the J equals 0 minus 1 neon-like zinc laser output at 21 nm by an order-of-magnitude with a comparable increase in efficiency. A double pumping laser pulse on neon-like yttrium lasing output at 15 nm obtained with the VULCAN laser (Rutherford Appleton Laboratory, England) was also found to increase the x-ray lasing efficiency. With adiabatically cooled recombination lasing, it is shown that approximately 2 ps pulses are optimum for achieving the desired ionization balance for lasing output. The possibility of achieving recombination lasing at short wavelengths on lithium-like ions with longer pulse lasers has been investigated using the ASTERIX laser (Max-Planck Quantenoptik, Germany). These results are presented and interpreted to provide possible directions for improving the efficiency of x-ray lasers.

X-ray Follow-ups of XSS J12270-4859: A Low-mass X-ray Binary with Gamma-ray Fermi-LAT Association

NASA Technical Reports Server (NTRS)

deMartino, D.; Belloni, T.; Falanga, M.; Papitto, A.; Motta, S.; Pellizzoni, A.; Evangelista, Y.; Piano, G.; Masetti, N.; Mouchet, M.;

Hidden explosives detector employing pulsed neutron and x-ray interrogation

DOEpatents

Schultz, F.J.; Caldwell, J.T.

1993-04-06

Methods and systems for the detection of small amounts of modern, highly-explosive nitrogen-based explosives, such as plastic explosives, hidden in airline baggage. Several techniques are employed either individually or combined in a hybrid system. One technique employed in combination is X-ray imaging. Another technique is interrogation with a pulsed neutron source in a two-phase mode of operation to image both nitrogen and oxygen densities. Another technique employed in combination is neutron interrogation to form a hydrogen density image or three-dimensional map. In addition, deliberately-placed neutron-absorbing materials can be detected.

Hidden explosives detector employing pulsed neutron and x-ray interrogation

DOEpatents

Schultz, Frederick J.; Caldwell, John T.

1993-01-01

Methods and systems for the detection of small amounts of modern, highly-explosive nitrogen-based explosives, such as plastic explosives, hidden in airline baggage. Several techniques are employed either individually or combined in a hybrid system. One technique employed in combination is X-ray imaging. Another technique is interrogation with a pulsed neutron source in a two-phase mode of operation to image both nitrogen and oxygen densities. Another technique employed in combination is neutron interrogation to form a hydrogen density image or three-dimensional map. In addition, deliberately-placed neutron-absorbing materials can be detected.

Can the 62 Day X-ray Period of ULX M82 X-1 Be Due to a Precessing Accretion Disk?

NASA Technical Reports Server (NTRS)

Pasham, Dheeraj R.; Strohmayer, Tod E.

2013-01-01

We have analyzed all the archival RXTE/PCA monitoring observations of the ultraluminous X-ray source (ULX) M82 X-1 in order to study the properties of its previously discovered 62 day X-ray period (Kaaret & Feng 2007). Based on the high coherence of the modulation it has been argued that the observed period is the orbital period of the binary. Utilizing a much longer data set than in previous studies we find: (1) The phase-resolved X-ray (3-15 keV) energy spectra - modeled with a thermal accretion disk and a power-law corona - suggest that the accretion disk's contribution to the total flux is responsible for the overall periodic modulation while the power-law flux remains approximately constant with phase. (2) Suggestive evidence for a sudden phase shift-of approximately 0.3 in phase (20 days)-between the first and the second halves of the light curve separated by roughly 1000 days. If confirmed, the implied timescale to change the period is approx. = 10 yrs, which is exceptionally fast for an orbital phenomenon. These independent pieces of evidence are consistent with the 62 day period being due to a precessing accretion disk, similar to the so-called super-orbital periods observed in systems like Her X-1, LMC X-4, and SS433. However, the timing evidence for a change in the period needs to be confirmed with additional observations. This should be possible with further monitoring of M82 with instruments such as the X-ray telescope (XRT) on board Swift.

In situ x-ray surface diffraction chamber for pulsed laser ablation film growth studies

NASA Astrophysics Data System (ADS)

Tischler, J. Z.; Eres, G.; Lowndes, D. H.; Larson, B. C.; Yoon, M.; Chiang, T.-C.; Zschack, Paul

2000-06-01

Pulsed laser deposition is highly successful for growing complex films such as oxides for substrate buffer layers and HiTc oxide superconductors. A surface diffraction chamber has been constructed to study fundamental aspects of non-equilibrium film growth using pulsed laser deposition. Due to the pulsed nature of the ablating laser, the deposited atoms arrive on the substrate in short sub-millisecond pulses. Thus monitoring the surface x-ray diffraction following individual laser pulses (with resolution down to ˜1 ms) provides direct information on surface kinetics and the aggregation process during film growth. The chamber design, based upon a 2+2 surface diffraction geometry with the modifications necessary for laser ablation, is discussed, and initial measurements on homo-epitaxial growth of SrTiO3 are presented.

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.

Experimental strategies for imaging bioparticles with femtosecond hard X-ray pulses

PubMed Central

Okamoto, Kenta; Bielecki, Johan; Maia, Filipe R. N. C.; Mühlig, Kerstin; Seibert, M. Marvin; Hantke, Max F.; Benner, W. Henry; Svenda, Martin; Ekeberg, Tomas; Loh, N. Duane; Pietrini, Alberto; Zani, Alessandro; Rath, Asawari D.; Westphal, Daniel; Kirian, Richard A.; Awel, Salah; Wiedorn, Max O.; van der Schot, Gijs; Carlsson, Gunilla H.; Hasse, Dirk; Sellberg, Jonas A.; Barty, Anton; Andreasson, Jakob; Boutet, Sébastien; Williams, Garth; Koglin, Jason; Hajdu, Janos; Larsson, Daniel S. D.

2017-01-01

This study explores the capabilities of the Coherent X-ray Imaging Instrument at the Linac Coherent Light Source to image small biological samples. The weak signal from small samples puts a significant demand on the experiment. Aerosolized Omono River virus particles of ∼40 nm in diameter were injected into the submicrometre X-ray focus at a reduced pressure. Diffraction patterns were recorded on two area detectors. The statistical nature of the measurements from many individual particles provided information about the intensity profile of the X-ray beam, phase variations in the wavefront and the size distribution of the injected particles. The results point to a wider than expected size distribution (from ∼35 to ∼300 nm in diameter). This is likely to be owing to nonvolatile contaminants from larger droplets during aerosolization and droplet evaporation. The results suggest that the concentration of nonvolatile contaminants and the ratio between the volumes of the initial droplet and the sample particles is critical in such studies. The maximum beam intensity in the focus was found to be 1.9 × 1012 photons per µm2 per pulse. The full-width of the focus at half-maximum was estimated to be 500 nm (assuming 20% beamline transmission), and this width is larger than expected. Under these conditions, the diffraction signal from a sample-sized particle remained above the average background to a resolution of 4.25 nm. The results suggest that reducing the size of the initial droplets during aerosolization is necessary to bring small particles into the scope of detailed structural studies with X-ray lasers. PMID:28512572

Experimental strategies for imaging bioparticles with femtosecond hard X-ray pulses

DOE PAGES

Daurer, Benedikt J.; Okamoto, Kenta; Bielecki, Johan; ...

2017-04-07

This study explores the capabilities of the Coherent X-ray Imaging Instrument at the Linac Coherent Light Source to image small biological samples. The weak signal from small samples puts a significant demand on the experiment. AerosolizedOmono River virusparticles of ~40 nm in diameter were injected into the submicrometre X-ray focus at a reduced pressure. Diffraction patterns were recorded on two area detectors. The statistical nature of the measurements from many individual particles provided information about the intensity profile of the X-ray beam, phase variations in the wavefront and the size distribution of the injected particles. The results point to amore » wider than expected size distribution (from ~35 to ~300 nm in diameter). This is likely to be owing to nonvolatile contaminants from larger droplets during aerosolization and droplet evaporation. The results suggest that the concentration of nonvolatile contaminants and the ratio between the volumes of the initial droplet and the sample particles is critical in such studies. The maximum beam intensity in the focus was found to be 1.9 × 10 12photons per µm 2per pulse. The full-width of the focus at half-maximum was estimated to be 500 nm (assuming 20% beamline transmission), and this width is larger than expected. Under these conditions, the diffraction signal from a sample-sized particle remained above the average background to a resolution of 4.25 nm. Finally, the results suggest that reducing the size of the initial droplets during aerosolization is necessary to bring small particles into the scope of detailed structural studies with X-ray lasers.« less

Single- and double-core-hole ion emission spectroscopy of transient neon plasmas produced by ultraintense x-ray laser pulses

NASA Astrophysics Data System (ADS)

Gao, Cheng; Zeng, Jiaolong; Yuan, Jianmin

2016-02-01

Single-core-hole (SCH) and double-core-hole (DCH) spectroscopy is investigated systematically for neon gas in the interaction with ultraintense x-ray pulses with photon energy from 937 eV to 2000 eV. A time-dependent rate equation, implemented in detailed level accounting approximation, is utilized to study the dynamical evolution of the level population and emission properties of the laser-produced highly transient plasmas. The plasma-density effects on level populations and charge-state distribution are demonstrated with an x-ray photon energy of 2000 eV. It is shown that atomic number density of relevant experiment is about 1 × 1018 cm-3, which is comparable to a recent experiment. At this density, we systematically investigate the emissivity of the transient neon plasmas. For laser photon energy in the range 937-1360 eV, resonant absorptions (RA) of 1s\\to {np} (n≥slant 2) transitions play important roles in time evolution of the population and DCH emission spectroscopy. The RA effects are illustrated in detail for an x-ray pulse of 944 eV photon energy, which creates the 1s\\to 2p RA from the SCH states (1s2{s}22{p}4, 1s2s2p5, and 1s2p6) of Ne3+. After averaging over the space and time distribution of x-ray pulse, DCH emission spectroscopy is studied at x-ray photon energies of 937, 944, 955, 968, 980, and 990 eV, where there exist 1s\\to 2p resonances from SCH states of Ne2+-Ne7+. The processes with producing DCH states are discussed. For x-ray photon energy larger than 1360 eV, no RA exist and transient plasmas show different features in the DCH spectroscopy.

Chandra's Observations of Jupiter's X-Ray Aurora During Juno Upstream and Apojove Intervals

NASA Technical Reports Server (NTRS)

Jackman, C.M.; Dunn, W.; Kraft, R.; Gladstone, R.; Branduardi-Raymont, G.; Knigge, C.; Altamirano, D.; Elsner, R.

2017-01-01

The Chandra space telescope has recently conducted a number of campaigns to observe Jupiter's X-ray aurora. The first set of campaigns took place in summer 2016 while the Juno spacecraft was upstream of the planet sampling the solar wind. The second set of campaigns took place in February, June and August 2017 at times when the Juno spacecraft was at apojove (expected close to the magnetopause). We report on these upstream and apojove campaigns including intensities and periodicities of auroral X-ray emissions. This new era of jovian X-ray astronomy means we have more data than ever before, long observing windows (up to 72 kiloseconds for this Chandra set), and successive observations relatively closely spaced in time. These features combine to allow us to pursue novel methods for examining periodicities in the X-ray emission. Our work will explore significance testing of emerging periodicities, and the search for coherence in X-ray pulsing over weeks and months, seeking to understand the robustness and regularity of previously reported hot spot X-ray emissions. The periods that emerge from our analysis will be compared against those which emerge from radio and UV wavelengths.

Optoelectronic Picosecond Detection of Synchrotron X-rays

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

Durbin, Stephen M.

2017-08-04

The goal of this research program was to develop a detector that would measure x-ray time profiles with picosecond resolution. This was specifically aimed for use at x-ray synchrotrons, where x-ray pulse profiles have Gaussian time spreads of 50-100 ps (FWHM), so the successful development of such a detector with picosecond resolution would permit x-ray synchrotron studies to break through the pulse width barrier. That is, synchrotron time-resolved studies are currently limited to pump-probe studies that cannot reveal dynamics faster than ~50 ps, whereas the proposed detector would push this into the physically important 1 ps domain. The results ofmore » this research effort, described in detail below, are twofold: 1) the original plan to rely on converting electronic signals from a semiconductor sensor into an optical signal proved to be insufficient for generating signals with the necessary time resolution and sensitivity to be widely applicable; and 2) an all-optical method was discovered whereby the x-rays are directly absorbed in an optoelectronic material, lithium tantalate, which can then be probed by laser pulses with the desired picosecond sensitivity for detection of synchrotron x-rays. This research program has also produced new fundamental understanding of the interaction of x-rays and optical lasers in materials that has now created a viable path for true picosecond detection of synchrotron x-rays.« less

Quasi-Periodic Pulse Amplitude Modulation in the Accreting Millisecond Pulsar IGR J00291+5934

NASA Technical Reports Server (NTRS)

Bult, Peter; van Doesburgh, Marieke; van der Klis, Michiel

2017-01-01

We introduce a new method for analyzing the a periodic variability of coherent pulsations in accreting millisecond X-ray pulsars (AMXPs). Our method involves applying a complex frequency correction to the time-domain lightcurve, allowing for the aperiodic modulation of the pulse amplitude to be robustly extracted in the frequency domain. We discuss the statistical properties of the resulting modulation spectrum and show how it can be correlated with the non-pulsed emission to determine if the periodic and a periodic variability are coupled processes. Using this method, we study the 598.88 Hz coherent pulsations of the AMXP IGR J00291+5934 as observed with the Rossi X-ray Timing Explorer and XMM-Newton. We demonstrate that our method easily confirms the known coupling between the pulsations and a strong 8 mHz quasi-periodic oscillation (QPO) in XMM-Newton observations. Applying our method to the RXTE observations, we further show, for the first time, that the much weaker 20 mHz QPO and its harmonic are also coupled with the pulsations. We discuss the implications of this coupling and indicate how it may be used to extract new information on the underlying accretion process.

Generation of double pulses at the Shanghai soft X-ray free electron laser facility

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

Wang, Zhen; Feng, Chao; Gu, Qiang

2017-01-28

In this paper, we present the promise of a new method generating double electron pulses with the picosecond-scale pulse length and the tunable interpulse spacing at several picoseconds, which has been witnessed an impressive potential of application in pump-probe techniques, two-color X-ray free electron laser (FEL), high-gradient witness bunch acceleration in a plasma, etc. Three-dimensional simulations are carried out to analyze the dynamic of the electron beam in the linear accelerator. Some comparisons have been made between the new method and the existing ways as well.

Pulse Repetition Frequency Effects In A High Average Power X-Ray Preionised Excimer Laser

NASA Astrophysics Data System (ADS)

Fontaine, Bernard L.; Forestier, Bernard M.; Delaporte, Philippe C.; Canarelli, Patrick

1989-10-01

Experimental study of waves damping in a high repetition rate excimer laser is undertaken. Excitation of laser active medium in a subsonic loop is achieved by means of a classical discharge, through transfer capacitors. The discharge stability is controlled by a wire ion plasma (w.i.p.) X-rays gun. The strong acoustic waves induced by the active medium excitation may lead to a decrease, at high PRF, of the energy per pulse. First results of the influence of a damping of induced density perturbations between two successive pulses are presented.

Apparatus for monitoring X-ray beam alignment

DOEpatents

Steinmeyer, Peter A.

1991-10-08

A self-contained, hand-held apparatus is provided for minitoring alignment of an X-ray beam in an instrument employing an X-ray source. The apparatus includes a transducer assembly containing a photoresistor for providing a range of electrical signals responsive to a range of X-ray beam intensities from the X-ray beam being aligned. A circuit, powered by a 7.5 VDC power supply and containing an audio frequency pulse generator whose frequency varies with the resistance of the photoresistor, is provided for generating a range of audible sounds. A portion of the audible range corresponds to low X-ray beam intensity. Another portion of the audible range corresponds to high X-ray beam intensity. The transducer assembly may include an a photoresistor, a thin layer of X-ray fluorescent material, and a filter layer transparent to X-rays but opaque to visible light. X-rays from the beam undergoing alignment penetrate the filter layer and excite the layer of fluorescent material. The light emitted from the fluorescent material alters the resistance of the photoresistor which is in the electrical circuit including the audio pulse generator and a speaker. In employing the apparatus, the X-ray beam is aligned to a complete alignment by adjusting the X-ray beam to produce an audible sound of the maximum frequency.

Apparatus for monitoring X-ray beam alignment

DOEpatents

Steinmeyer, P.A.

1991-10-08

A self-contained, hand-held apparatus is provided for monitoring alignment of an X-ray beam in an instrument employing an X-ray source. The apparatus includes a transducer assembly containing a photoresistor for providing a range of electrical signals responsive to a range of X-ray beam intensities from the X-ray beam being aligned. A circuit, powered by a 7.5 VDC power supply and containing an audio frequency pulse generator whose frequency varies with the resistance of the photoresistor, is provided for generating a range of audible sounds. A portion of the audible range corresponds to low X-ray beam intensity. Another portion of the audible range corresponds to high X-ray beam intensity. The transducer assembly may include an a photoresistor, a thin layer of X-ray fluorescent material, and a filter layer transparent to X-rays but opaque to visible light. X-rays from the beam undergoing alignment penetrate the filter layer and excite the layer of fluorescent material. The light emitted from the fluorescent material alters the resistance of the photoresistor which is in the electrical circuit including the audio pulse generator and a speaker. In employing the apparatus, the X-ray beam is aligned to a complete alignment by adjusting the X-ray beam to produce an audible sound of the maximum frequency. 2 figures.

X-Ray Timing Analysis of Cyg X-3 Using AstroSat/LAXPC: Detection of Milli-hertz Quasi-periodic Oscillations during the Flaring Hard X-Ray State

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

Pahari, Mayukh; Misra, Ranjeev; Antia, H M

We present here results from the X-ray timing and spectral analysis of the X-ray binary Cyg X-3 using observations from the Large Area X-ray proportional Counter on board AstroSat . Consecutive light curves observed over a period of one year show the binary orbital period of 17253.56 ± 0.19 s. Another low-amplitude, slow periodicity of the order of 35.8 ± 1.4 days is observed, which may be due to the orbital precession as suggested earlier by Molteni et al. During the rising binary phase, power density spectra from different observations during the flaring hard X-ray state show quasi-periodic oscillations (QPOs)more » at ∼5–8 mHz, ∼12–14 mHz, and ∼18–24 mHz frequencies at the minimum confidence of 99%. However, during the consecutive binary decay phase, no QPO is detected up to 2 σ significance. Energy-dependent time-lag spectra show soft lag (soft photons lag hard photons) at the mHz QPO frequency and the fractional rms of the QPO increases with the photon energy. During the binary motion, the observation of mHz QPOs during the rising phase of the flaring hard state may be linked to the increase in the supply of the accreting material in the disk and corona via stellar wind from the companion star. During the decay phase, the compact source moves in the outer wind region causing the decrease in supply of material for accretion. This may cause weakening of the mHz QPOs below the detection limit. This is also consistent with the preliminary analysis of the orbital phase-resolved energy spectra presented in this paper.« less

Discovery and Orbital Determination of the Transient X-Ray Pulsar GRO J1750-27

NASA Technical Reports Server (NTRS)

Scott, D. M.; Finger, M. H.; Wilson, R. B.; Koh, D. T.; Prince, T. A.; Vaughan, B. A.; Chakrabarty, D.

1997-01-01

We report on the discovery and hard X-ray (20 - 70 keV) observations of the 4.45 s period transient X-ray pulsar GRO J1750-27 with the BATSE all-sky monitor on board CGRO. A relatively faint out- burst (less than 30 mcrab peak) lasting at least 60 days was observed during which the spin-up rate peaked at 38 pHz/s and was correlated with the pulsed intensity. An orbit with a period of 29.8 days was found. The large spin-up rate, spin period, and orbital period together suggest that accretion is occurring from a disk and that the outburst is a "giant" outburst typical of a Be/X-ray transient system. No optical counterpart has yet been reported.

Discovery and Orbital Determination of the Transient X-Ray Pulsar GRO J1750-27

NASA Technical Reports Server (NTRS)

Scott, D. M.; Finger, M. H.; Wilson, R. B.; Koh, D. T.; Prince, T. A.; Vaughan, B. A.; Chakrabarty, D.

1997-01-01

We report on the discovery and hard X-ray (20-70 keV) observations of the 4.45 second period transient X-ray pulsar GRO J1750-27 with the BATSE all-sky monitor on board CCRO. A relatively faint outburst (< 30 mCrab peak) lasting at least 60 days was observed during which the spin-up rate peaked at 38 pHz/sec and was correlated with the pulsed intensity. An orbit with a period of 29.8 days was found. The large spin-up rate, spin period and orbital period together suggest that accretion is occurring from a disk and that the outburst is a 'giant' outburst typical of a Be/X-ray transient system. No optical counterpart has been reported yet.

Performance verification and system integration tests of the pulse shape processor for the soft x-ray spectrometer onboard ASTRO-H

NASA Astrophysics Data System (ADS)

Takeda, Sawako; Tashiro, Makoto S.; Ishisaki, Yoshitaka; Tsujimoto, Masahiro; Seta, Hiromi; Shimoda, Yuya; Yamaguchi, Sunao; Uehara, Sho; Terada, Yukikatsu; Fujimoto, Ryuichi; Mitsuda, Kazuhisa

2014-07-01

The soft X-ray spectrometer (SXS) aboard ASTRO-H is equipped with dedicated digital signal processing units called pulse shape processors (PSPs). The X-ray microcalorimeter system SXS has 36 sensor pixels, which are operated at 50 mK to measure heat input of X-ray photons and realize an energy resolution of 7 eV FWHM in the range 0.3-12.0 keV. Front-end signal processing electronics are used to filter and amplify the electrical pulse output from the sensor and for analog-to-digital conversion. The digitized pulses from the 36 pixels are multiplexed and are sent to the PSP over low-voltage differential signaling lines. Each of two identical PSP units consists of an FPGA board, which assists the hardware logic, and two CPU boards, which assist the onboard software. The FPGA board triggers at every pixel event and stores the triggering information as a pulse waveform in the installed memory. The CPU boards read the event data to evaluate pulse heights by an optimal filtering algorithm. The evaluated X-ray photon data (including the pixel ID, energy, and arrival time information) are transferred to the satellite data recorder along with event quality information. The PSP units have been developed and tested with the engineering model (EM) and the flight model. Utilizing the EM PSP, we successfully verified the entire hardware system and the basic software design of the PSPs, including their communication capability and signal processing performance. In this paper, we show the key metrics of the EM test, such as accuracy and synchronicity of sampling clocks, event grading capability, and resultant energy resolution.

A laser driven pulsed X-ray backscatter technique for enhanced penetrative imaging.

PubMed

Deas, R M; Wilson, L A; Rusby, D; Alejo, A; Allott, R; Black, P P; Black, S E; Borghesi, M; Brenner, C M; Bryant, J; Clarke, R J; Collier, J C; Edwards, B; Foster, P; Greenhalgh, J; Hernandez-Gomez, C; Kar, S; Lockley, D; Moss, R M; Najmudin, Z; Pattathil, R; Symes, D; Whittle, M D; Wood, J C; McKenna, P; Neely, D

2015-01-01

X-ray backscatter imaging can be used for a wide range of imaging applications, in particular for industrial inspection and portal security. Currently, the application of this imaging technique to the detection of landmines is limited due to the surrounding sand or soil strongly attenuating the 10s to 100s of keV X-rays required for backscatter imaging. Here, we introduce a new approach involving a 140 MeV short-pulse (< 100 fs) electron beam generated by laser wakefield acceleration to probe the sample, which produces Bremsstrahlung X-rays within the sample enabling greater depths to be imaged. A variety of detector and scintillator configurations are examined, with the best time response seen from an absorptive coated BaF2 scintillator with a bandpass filter to remove the slow scintillation emission components. An X-ray backscatter image of an array of different density and atomic number items is demonstrated. The use of a compact laser wakefield accelerator to generate the electron source, combined with the rapid development of more compact, efficient and higher repetition rate high power laser systems will make this system feasible for applications in the field. Content includes material subject to Dstl (c) Crown copyright (2014). Licensed under the terms of the Open Government Licence except where otherwise stated. To view this licence, visit http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@ nationalarchives.gsi.gov.uk.

Soft X-Ray Optics by Pulsed Laser Deposition

NASA Technical Reports Server (NTRS)

Fernandez, Felix E.

1996-01-01

Mo/Si and C/Co multilayers for soft x-ray optics were designed for spectral regions of interest in possible applications. Fabrication was effected by Pulsed Laser Deposition using Nd:YAG (355 nm) or excimer (248 nm) lasers in order to evaluate the suitability of this technique. Results for Mo/Si structures were not considered satisfactory due mainly to problems with particulate production and target surface modification during Si ablation. These problems may be alleviated by a two-wavelength approach, using separate lasers for each target. Results for C/Co multilayers are much more encouraging, since indication of good layering was observed for extremely thin layers. We expect to continue investigating this possibility. In order to compete with traditional PVD techniques, it is necessary to achieve film coverage uniformity over large enough areas. It was shown that this is feasible, and novel means of achieving it were devised.

Pump–probe spectrometer for measuring x-ray induced strain

DOE PAGES

Loether, A.; Adams, B. W.; DiCharia, A.; ...

2016-04-20

A hard x-ray pump–probe spectrometer using a multi-crystal Bragg reflector is demonstrated at a third generation synchrotron source. This device derives both broadband pump and monochromatic probe pulses directly from a single intense, broadband x-ray pulse centered at 8.767 keV. In conclusion, we present a proof-of-concept experiment which directly measures x-ray induced crystalline lattice strain.

Oxidized nanocrystalline Fe-Cu pseudoalloy subjected to high pressure and electrodischarge pulses: Mössbauer and x-ray investigations

NASA Astrophysics Data System (ADS)

Gavriliuk, A. G.; Voitkovsky, V. S.; Sidorov, V. A.; Filonenko, V. P.; Tsiok, O. B.; Khvostantsev, L. G.

1998-05-01

Nanocrystalline Fe15Cu85 pseudoalloy has been subjected to pulsed heating up to 1500 K at high pressure (8 GPa). Two regimes were studied: the direct heating using electrodischarge through the sample and indirect heating with the use of cylindrical heater around the sample. The temperature and time conditions in both types of experiments were adjusted to be equivalent. The discharge parameters (stored energy, discharge time, and magnitude of current pulse) were sufficient to move defects by conduction electrons, but insufficient to melt the sample. The properties of treated samples were studied using Mössbauer absorption spectra and x-ray diffraction for three types of samples: (a) primary powder treated by high pressure up to 8 GPa, (b) powder subjected to indirect pulsed heating at 8 GPa, (c) powder treated by electrical pulses at 8 GPa. The x-ray diffraction pattern of primary powder exhibits peaks of copper, iron, and copper oxide (CuO). The Mössbauer spectrum of primary powder exhibits six peaks of alpha iron and some peaks near zero velocity due to the small iron clusters in the copper matrix and ultrafine clusters of paramagnetic phase x-Fe2O3. The transformation of CuO to Cu2O takes place in the course of indirect heating, the Mössbauer spectrum being almost unchanged. The direct electrodischarge heating causes the appearance of new magnetic phase with the magnetic field on iron nucleus 505 kOe, which corresponds to α-Fe2O3. The formation of α-Fe2O3 was confirmed by x-ray diffraction. At the same time the transformation of CuO to Cu2O is incomplete. These experiments demonstrate that high density current pulses, causing the electron wind, can be a useful tool to influence the structure of nanocrystalline powder.

Characterization of temporal coherence of hard X-ray free-electron laser pulses with single-shot interferograms

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

Osaka, Taito; Hirano, Takashi; Morioka, Yuki

Temporal coherence is one of the most fundamental characteristics of light, connecting to spectral information through the Fourier transform relationship between time and frequency. Interferometers with a variable path-length difference (PLD) between the two branches have widely been employed to characterize temporal coherence properties for broad spectral regimes. Hard X-ray interferometers reported previously, however, have strict limitations in their operational photon energies, due to the specific optical layouts utilized to satisfy the stringent requirement for extreme stability of the PLD at sub-ångström scales. The work presented here characterizes the temporal coherence of hard X-ray free-electron laser (XFEL) pulses by capturingmore » single-shot interferograms. Since the stability requirement is drastically relieved with this approach, it was possible to build a versatile hard X-ray interferometer composed of six separate optical elements to cover a wide photon energy range from 6.5 to 11.5 keV while providing a large variable delay time of up to 47 ps at 10 keV. A high visibility of up to 0.55 was observed at a photon energy of 10 keV. The visibility measurement as a function of time delay reveals a mean coherence time of 5.9 ± 0.7 fs, which agrees with that expected from the single-shot spectral information. In conclusion, this is the first result of characterizing the temporal coherence of XFEL pulses in the hard X-ray regime and is an important milestone towards ultra-high energy resolutions at micro-electronvolt levels in time-domain X-ray spectroscopy, which will open up new opportunities for revealing dynamic properties in diverse systems on timescales from femtoseconds to nanoseconds, associated with fluctuations from ångström to nanometre spatial scales.« less

Characterization of temporal coherence of hard X-ray free-electron laser pulses with single-shot interferograms

DOE PAGES

Osaka, Taito; Hirano, Takashi; Morioka, Yuki; ...

2017-10-13

Temporal coherence is one of the most fundamental characteristics of light, connecting to spectral information through the Fourier transform relationship between time and frequency. Interferometers with a variable path-length difference (PLD) between the two branches have widely been employed to characterize temporal coherence properties for broad spectral regimes. Hard X-ray interferometers reported previously, however, have strict limitations in their operational photon energies, due to the specific optical layouts utilized to satisfy the stringent requirement for extreme stability of the PLD at sub-ångström scales. The work presented here characterizes the temporal coherence of hard X-ray free-electron laser (XFEL) pulses by capturingmore » single-shot interferograms. Since the stability requirement is drastically relieved with this approach, it was possible to build a versatile hard X-ray interferometer composed of six separate optical elements to cover a wide photon energy range from 6.5 to 11.5 keV while providing a large variable delay time of up to 47 ps at 10 keV. A high visibility of up to 0.55 was observed at a photon energy of 10 keV. The visibility measurement as a function of time delay reveals a mean coherence time of 5.9 ± 0.7 fs, which agrees with that expected from the single-shot spectral information. In conclusion, this is the first result of characterizing the temporal coherence of XFEL pulses in the hard X-ray regime and is an important milestone towards ultra-high energy resolutions at micro-electronvolt levels in time-domain X-ray spectroscopy, which will open up new opportunities for revealing dynamic properties in diverse systems on timescales from femtoseconds to nanoseconds, associated with fluctuations from ångström to nanometre spatial scales.« less

Double core-hole emissivity of transient aluminum plasmas produced in the interaction with ultra-intense x-ray laser pulse

NASA Astrophysics Data System (ADS)

Gao, Cheng; Zeng, Jiaolong; Yuan, Jianmin

2015-11-01

Emissivity of single core-hole (SCH) and double core-hole (DCH) states of aluminum plasmas produced in the interaction with ultra-intense x-ray laser pulse interaction are investigated systematically by solving the time-dependent rate equation implemented in the detailed level accounting approximation. We first demonstrated the plasma density effects on level populations and charge state distribution. Compared with recent experiments, it is shown that the plasma density effects play important roles in the evolution dynamics. Then we systematically investigated the emissivity of the transient aluminum plasmas produced by the x-ray laser pulses with a few photon energies above the threshold photon energy to create DCH states. For the laser photon energy where there are resonant absorptions (RA), 1s-np transitions with both full 1s and SCH 1s states play important roles in time evolution of the population and DCH emission spectroscopy. The significant RA effects are illustrated in detail for x-ray pulses, which creates the 1s-2p resonant absorption from the SCH states of Al VII. With the increase of the photon energy, the emissions from lower charge states become larger.

Time-resolved study of SrTiO3 homoepitaxial pulsed-laser deposition using surface x-ray diffraction

NASA Astrophysics Data System (ADS)

Eres, G.; Tischler, J. Z.; Yoon, M.; Larson, B. C.; Rouleau, C. M.; Lowndes, D. H.; Zschack, P.

2002-05-01

Homoepitaxy of SrTiO3 by pulsed-laser deposition has been studied using in situ time-resolved surface x-ray diffraction in the temperature range of 310 °C to 780 °C. Using a two-detector configuration, surface x-ray diffraction intensities were monitored simultaneously at the (0 0 1/2) specular and the (0 1 1/2) off-specular truncation rod positions. Abrupt intensity changes in both the specular and off-specular rods after laser pulses indicated prompt crystallization into SrTiO3 layers followed by slower intra- and interlayer surface rearrangements on time scales of seconds. Specular rod intensity oscillations indicated layer-by-layer growth, while off-specular rod intensity measurements suggested the presence of transient in-plane lattice distortions for depositions above 600 °C.

Polarization control in an X-ray free-electron laser

DOE PAGES

Lutman, Alberto A.; MacArthur, James P.; Ilchen, Markus; ...

2016-05-09

X-ray free-electron lasers are unique sources of high-brightness coherent radiation. However, existing devices supply only linearly polarized light, precluding studies of chiral dynamics. A device called the Delta undulator has been installed at the Linac Coherent Light Source (LCLS) to provide tunable polarization. With a reverse tapered planar undulator line to pre-microbunch the beam and the novel technique of beam diverting, hundreds of microjoules of circularly polarized X-ray pulses are produced at 500–1,200 eV. These X-ray pulses are tens of femtoseconds long, have a degree of circular polarization of 0.98 –0.04 +0.02 at 707 eV and may be scanned inmore » energy. We also present a new two-colour X-ray pump–X-ray probe operating mode for the LCLS. As a result, energy differences of ΔE/E = 2.4% are supported, and the second pulse can be adjusted to any elliptical polarization. In this mode, the pointing, timing, intensity and wavelength of the two pulses can be modified.« less

Modeling the performance of a photon counting x-ray detector for CT: energy response and pulse pileup effects.

PubMed

Taguchi, Katsuyuki; Zhang, Mengxi; Frey, Eric C; Wang, Xiaolan; Iwanczyk, Jan S; Nygard, Einar; Hartsough, Neal E; Tsui, Benjamin M W; Barber, William C

2011-02-01

Recently, photon counting x-ray detectors (PCXDs) with energy discrimination capabilities have been developed for potential use in clinical computed tomography (CT) scanners. These PCXDs have great potential to improve the quality of CT images due to the absence of electronic noise and weights applied to the counts and the additional spectral information. With high count rates encountered in clinical CT, however, coincident photons are recorded as one event with a higher or lower energy due to the finite speed of the PCXD. This phenomenon is called a "pulse pileup event" and results in both a loss of counts (called "deadtime losses") and distortion of the recorded energy spectrum. Even though the performance of PCXDs is being improved, it is essential to develop algorithmic methods based on accurate models of the properties of detectors to compensate for these effects. To date, only one PCXD (model DXMCT-1, DxRay, Inc., Northridge, CA) has been used for clinical CT studies. The aim of that study was to evaluate the agreement between data measured by DXMCT-1 and those predicted by analytical models for the energy response, the deadtime losses, and the distorted recorded spectrum caused by pulse pileup effects. An energy calibration was performed using 99mTc (140 keV), 57Co (122 keV), and an x-ray beam obtained with four x-ray tube voltages (35, 50, 65, and 80 kVp). The DXMCT-1 was placed 150 mm from the x-ray focal spot; the count rates and the spectra were recorded at various tube current values from 10 to 500 microA for a tube voltage of 80 kVp. Using these measurements, for each pulse height comparator we estimated three parameters describing the photon energy-pulse height curve, the detector deadtime tau, a coefficient k that relates the x-ray tube current I to an incident count rate a by a = k x I, and the incident spectrum. The mean pulse shape of all comparators was acquired in a separate study and was used in the model to estimate the distorted recorded

A1540-53, an eclipsing X-ray binary pulsator

NASA Technical Reports Server (NTRS)

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

1977-01-01

An eclipsing X-ray binary pulsator consistent with the location of A1540-53 has been observed. The source pulse period was 528.93 + or - 0.10 s. The binary nature is confirmed by a Doppler curve for the pulsation period. The eclipse angle of 30.5 + or - 3 deg and the 4-hour transition to and from eclipse suggest an early-type giant or supergiant primary star.

Deep Chandra Survey of the Small Magellanic Cloud. II. Timing Analysis of X-Ray Pulsars

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

Hong, JaeSub; Antoniou, Vallia; Zezas, Andreas

We report the timing analysis results of X-ray pulsars from a recent deep Chandra survey of the Small Magellanic Cloud (SMC). We analyzed a total exposure of 1.4 Ms from 31 observations over a 1.2 deg{sup 2} region in the SMC under a Chandra X-ray Visionary Program. Using the Lomb–Scargle and epoch-folding techniques, we detected periodic modulations from 20 pulsars and a new candidate pulsar. The survey also covered 11 other pulsars with no clear sign of periodic modulation. The 0.5–8 keV X-ray luminosity ( L {sub X} ) of the pulsars ranges from 10{sup 34} to 10{sup 37} ergmore » s{sup −1} at 60 kpc. All of the Chandra sources with L {sub X} ≳ 4 × 10{sup 35} erg s{sup −1} exhibit X-ray pulsations. The X-ray spectra of the SMC pulsars (and high-mass X-ray binaries) are in general harder than those of the SMC field population. All but SXP 8.02 can be fitted by an absorbed power-law model with a photon index of Γ ≲ 1.5. The X-ray spectrum of the known magnetar SXP 8.02 is better fitted with a two-temperature blackbody model. Newly measured pulsation periods of SXP 51.0, SXP 214, and SXP 701, are significantly different from the previous XMM-Newton and RXTE measurements. This survey provides a rich data set for energy-dependent pulse profile modeling. Six pulsars show an almost eclipse-like dip in the pulse profile. Phase-resolved spectral analysis reveals diverse spectral variations during pulsation cycles: e.g., for an absorbed power-law model, some exhibit an (anti)-correlation between absorption and X-ray flux, while others show more intrinsic spectral variation (i.e., changes in photon indices).« less

Thomson-backscattered x rays from laser-accelerated electrons.

PubMed

Schwoerer, H; Liesfeld, B; Schlenvoigt, H-P; Amthor, K-U; Sauerbrey, R

2006-01-13

We present the first observation of Thomson-backscattered light from laser-accelerated electrons. In a compact, all-optical setup, the "photon collider," a high-intensity laser pulse is focused into a pulsed He gas jet and accelerates electrons to relativistic energies. A counterpropagating laser probe pulse is scattered from these high-energy electrons, and the backscattered x-ray photons are spectrally analyzed. This experiment demonstrates a novel source of directed ultrashort x-ray pulses and additionally allows for time-resolved spectroscopy of the laser acceleration of electrons.

Long-Term Properties of Accretion Discs in X-ray Binaries. 1; The Variable Third Period in SMC X-1

NASA Technical Reports Server (NTRS)

Charles, P. A.; Clarkson, W. I.; Coe, M. J.; Laycock, S.; Tout, M.; Wilson, C.; Six, N. Frank (Technical Monitor)

2002-01-01

Long term X-ray monitoring data from the RXTE All Sky Monitor (ASM) reveal that the third (superorbital) period in SMC X-1 is not constant but varies between 40-60 days. A dynamic power spectrum analysis indicates that the third period has been present continuously throughout the five years of ASM observations. This period changed smoothly from 60 days to 45 days and then returned to its former value, on a timescale of approximately 1600 days. During the nearly 4 years of overlap between the CGRO & RXTE missions, the simultaneous BATSE hard X-ray data confirm this variation in SMC X-1. Sources of systematic error and possible artefacts are investigated and found to be incapable of reproducing the results reported here. Our disco cry of such an instability in the superorbital period of SMC X-1 is interpreted in the context of recent theoretical studies of warped, precessing accretion discs. We find that the behaviour of SMC X-1 is consistent with a radiation - driven warping model.

X-ray laser microscope apparatus

DOEpatents

Suckewer, Szymon; DiCicco, Darrell S.; Hirschberg, Joseph G.; Meixler, Lewis D.; Sathre, Robert; Skinner, Charles H.

1990-01-01

A microscope consisting of an x-ray contact microscope and an optical microscope. The optical, phase contrast, microscope is used to align a target with respect to a source of soft x-rays. The source of soft x-rays preferably comprises an x-ray laser but could comprise a synchrotron or other pulse source of x-rays. Transparent resist material is used to support the target. The optical microscope is located on the opposite side of the transparent resist material from the target and is employed to align the target with respect to the anticipated soft x-ray laser beam. After alignment with the use of the optical microscope, the target is exposed to the soft x-ray laser beam. The x-ray sensitive transparent resist material whose chemical bonds are altered by the x-ray beam passing through the target mater GOVERNMENT LICENSE RIGHTS This invention was made with government support under Contract No. De-FG02-86ER13609 awarded by the Department of Energy. The Government has certain rights in this invention.

"X-Ray Transients in Star-Forming Regions" and "Hard X-Ray Emission from X-Ray Bursters"

NASA Technical Reports Server (NTRS)

Halpern, Jules P.; Kaaret, Philip

1999-01-01

This grant funded work on the analysis of data obtained with the Burst and Transient Experiment (BATSE) on the Compton Gamma-Ray Observatory. The goal of the work was to search for hard x-ray transients in star forming regions using the all-sky hard x-ray monitoring capability of BATSE. Our initial work lead to the discovery of a hard x-ray transient, GRO J1849-03. Follow-up observations of this source made with the Wide Field Camera on BeppoSAX showed that the source should be identified with the previously known x-ray pulsar GS 1843-02 which itself is identified with the x-ray source X1845-024 originally discovered with the SAS-3 satellite. Our identification of the source and measurement of the outburst recurrence time, lead to the identification of the source as a Be/X-ray binary with a spin period of 94.8 s and an orbital period of 241 days. The funding was used primarily for partial salary and travel support for John Tomsick, then a graduate student at Columbia University. John Tomsick, now Dr. Tomsick, received his Ph.D. from Columbia University in July 1999, based partially on results obtained under this investigation. He is now a postdoctoral research scientist at the University of California, San Diego.

Evidence for Quasi-Periodic X-ray Dips from an ULX: Implications for the Binary Motion and the Orbital Inclination

NASA Technical Reports Server (NTRS)

Pasham, Dheeraj R.; Strohmayer, Tod E.

2012-01-01

We report results from long-term X-ray (0.3-8.0 keY) monitoring of the ultraluminous X-ray source NGC 5408 X-1 with the Swift/X-Ray Telescope. Our primary results are: (1) the discovery of quasi-periodic dips in the X-ray intensity that recur on average every 243 days, (2) the detection of an energy-dependent (variability amplitude decreases with increasing energy), quasi-sinusoidal X-ray modulation with a period of 112.6 +/- 4 days the amplitude of which decreases during the second half of the light curve and (3) energy spectral evidence for an increase in photoelectric absorption during the last continuous segment of the data, possibly due to a change in the ionization state of the circumbinary material. We interpret the X-ray modulations in the context of binary motion in analogy to that seen in high-inclination low-mass X-ray binaries. If correct, this implies that NGC 5408 X-1 is in a binary with an orbital period of 243 +/- 23 days in contrast to the 115.5 day quasi-sinusoidal period previously reported. In addition, if the X-ray modulation is caused by vertically structured obscuring material in the accretion disk (similar to the phenomenon of dipping LMXBs), this would imply a high value for the inclination of the orbit. A comparison with estimates from accreting X-ray binaries suggests an inclination approx > 60 deg. We note that, in principle, a precessing accretion disk could also produce the observed X-ray modulations.

Femtosecond all-optical synchronization of an X-ray free-electron laser

DOE PAGES

Schulz, S.; Grguraš, I.; Behrens, C.; ...

2015-01-20

Many advanced applications of X-ray free-electron lasers require pulse durations and time resolutions of only a few femtoseconds. To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed. Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses. Crucially, our analysis indicates that the performance of this optical synchronization is limited primarilymore » by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses.« less

Femtosecond all-optical synchronization of an X-ray free-electron laser

PubMed Central

Schulz, S.; Grguraš, I.; Behrens, C.; Bromberger, H.; Costello, J. T.; Czwalinna, M. K.; Felber, M.; Hoffmann, M. C.; Ilchen, M.; Liu, H. Y.; Mazza, T.; Meyer, M.; Pfeiffer, S.; Prędki, P.; Schefer, S.; Schmidt, C.; Wegner, U.; Schlarb, H.; Cavalieri, A. L.

2015-01-01

Many advanced applications of X-ray free-electron lasers require pulse durations and time resolutions of only a few femtoseconds. To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed. Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses. Crucially, our analysis indicates that the performance of this optical synchronization is limited primarily by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses. PMID:25600823

Development of X-ray CCD camera based X-ray micro-CT system

NASA Astrophysics Data System (ADS)

Sarkar, Partha S.; Ray, N. K.; Pal, Manoj K.; Baribaddala, Ravi; Agrawal, Ashish; Kashyap, Y.; Sinha, A.; Gadkari, S. C.

2017-02-01

Availability of microfocus X-ray sources and high resolution X-ray area detectors has made it possible for high resolution microtomography studies to be performed outside the purview of synchrotron. In this paper, we present the work towards the use of an external shutter on a high resolution microtomography system using X-ray CCD camera as a detector. During micro computed tomography experiments, the X-ray source is continuously ON and owing to the readout mechanism of the CCD detector electronics, the detector registers photons reaching it during the read-out period too. This introduces a shadow like pattern in the image known as smear whose direction is defined by the vertical shift register. To resolve this issue, the developed system has been incorporated with a synchronized shutter just in front of the X-ray source. This is positioned in the X-ray beam path during the image readout period and out of the beam path during the image acquisition period. This technique has resulted in improved data quality and hence the same is reflected in the reconstructed images.

Ultrafast Coulomb explosion of a diiodomethane molecule induced by an X-ray free-electron laser pulse.

PubMed

Takanashi, Tsukasa; Nakamura, Kosuke; Kukk, Edwin; Motomura, Koji; Fukuzawa, Hironobu; Nagaya, Kiyonobu; Wada, Shin-Ichi; Kumagai, Yoshiaki; Iablonskyi, Denys; Ito, Yuta; Sakakibara, Yuta; You, Daehyun; Nishiyama, Toshiyuki; Asa, Kazuki; Sato, Yuhiro; Umemoto, Takayuki; Kariyazono, Kango; Ochiai, Kohei; Kanno, Manabu; Yamazaki, Kaoru; Kooser, Kuno; Nicolas, Christophe; Miron, Catalin; Asavei, Theodor; Neagu, Liviu; Schöffler, Markus; Kastirke, Gregor; Liu, Xiao-Jing; Rudenko, Artem; Owada, Shigeki; Katayama, Tetsuo; Togashi, Tadashi; Tono, Kensuke; Yabashi, Makina; Kono, Hirohiko; Ueda, Kiyoshi

2017-08-02

Coulomb explosion of diiodomethane CH 2 I 2 molecules irradiated by ultrashort and intense X-ray pulses from SACLA, the Japanese X-ray free electron laser facility, was investigated by multi-ion coincidence measurements and self-consistent charge density-functional-based tight-binding (SCC-DFTB) simulations. The diiodomethane molecule, containing two heavy-atom X-ray absorbing sites, exhibits a rather different charge generation and nuclear motion dynamics compared to iodomethane CH 3 I with only a single heavy atom, as studied earlier. We focus on charge creation and distribution in CH 2 I 2 in comparison to CH 3 I. The release of kinetic energy into atomic ion fragments is also studied by comparing SCC-DFTB simulations with the experiment. Compared to earlier simulations, several key enhancements are made, such as the introduction of a bond axis recoil model, where vibrational energy generated during charge creation processes induces only bond stretching or shrinking. We also propose an analytical Coulomb energy partition model to extract the essential mechanism of Coulomb explosion of molecules from the computed and the experimentally measured kinetic energies of fragment atomic ions by partitioning each pair Coulomb interaction energy into two ions of the pair under the constraint of momentum conservation. Effective internuclear distances assigned to individual fragment ions at the critical moment of the Coulomb explosion are then estimated from the average kinetic energies of the ions. We demonstrate, with good agreement between the experiment and the SCC-DFTB simulation, how the more heavily charged iodine fragments and their interplay define the characteristic features of the Coulomb explosion of CH 2 I 2 . The present study also confirms earlier findings concerning the magnitude of bond elongation in the ultrashort X-ray pulse duration, showing that structural damage to all but C-H bonds does not develop to a noticeable degree in the pulse length of ∼10

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Feasibility of generation of picosecond and subpicosecond x-ray pulses in thin films

NASA Astrophysics Data System (ADS)

Gordienko, Vyacheslav M.; Dzhidzhoev, M. S.; Kolchin, V. V.; Magnitskiy, Sergey A.; Platonenko, Viktor T.; Savel'ev, Andrei B.; Tarasevitch, A. P.

1995-02-01

The characteristics of a femtosecond laser plasma, formed by irradiation of a thin freely suspended carbon film, are investigated numerically. It is shown that the use of thin films can increase considerably the electron temperature of a femtosecond laser plasma and make it possible to generate x-rays of shorter wavelengths. This method can also be used to increase the efficiency of conversion of the energy of laser pulses into the radiation emitted by hydrogen-like carbon ions without a significant increase in the duration of x-ray pulses.

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.

Periodic Recurrence Patterns In X-Ray Solar Flare Appearances

NASA Astrophysics Data System (ADS)

Gyenge, N.; Erdélyi, R.

2018-06-01

The temporal recurrence of micro-flare events is studied for a time interval before and after of major solar flares. Our sample is based on the X-ray flare observations by the Geostationary Operational Environmental Satellite (GOES) and Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The analyzed data contain 1330/301 M-class and X-class GOES/RHESSI energetic solar flares and 4062/4119 GOES/RHESSI micro-flares covering the period elapse since 2002. The temporal analysis of recurrence, by Fast Fourier Transform, of the micro-flares, shows multiple significant periods. Based on the GOES and RHESSI data, the temporal analysis also demonstrates that multiple periods manifest simultaneously in both statistical samples without any significant shift over time. In the GOES sample, the detected significant periods are: 11.33, 5.61, 3.75, 2.80, and 2.24 minutes. The RHESSI data show similar significant periods at 8.54, 5.28, 3.66, 2.88, and 2.19 minutes. The periods are interpreted as signatures of standing oscillations, with the longest period (P 1) being the fundamental and others being higher harmonic modes. The period ratio of the fundamental and higher harmonics (P 1/P N ) is also analyzed. The standing modes may be signatures of global oscillations of the entire solar atmosphere encompassing magnetized plasma from the photosphere to the corona in active regions.

The Mysterious sdO X-ray Binary BD+37°442

NASA Astrophysics Data System (ADS)

Heber, U.; Geier, S.; Irrgang, A.; Schneider, D.; Barbu-Barna, I.; Mereghetti, S.; La Palombara, N.

2014-04-01

Pulsed X-ray emission in the luminous, helium-rich sdO BD +37°442 has recently been discovered (La Palombara et al. 2012). It was suggested that the sdO star has a neutron star or white dwarf companion with a spin period of 19.2 s. After HD 49798, which has a massive white dwarf companion spinning at 13.2 s in an 1.55 day orbit, this is only the second O-type subdwarf from which X-ray emission has been detected. We report preliminary results of our ongoing campaign to obtain time-resolved high-resolution spectroscopy using the CAFE instrument at Calar Alto observatory and SARG at the Telescopio Nationale Galileo. Atmospheric parameters were derived via a quantitative NLTE spectral analysis. The line fits hint at an unusually large projected rotation velocity. Therefore it seemed likely that BD +37°442 is a binary similar to HD 49798 and that the orbital period is also similar. The level of X-ray emission from BD +37°442 could be explained by accretion from the sdO wind by a neutron star orbiting at a period of less than ten days. Hence, we embarked on radial velocity monitoring in order to derive the binary parameters of the BD+37°442 system and obtained 41 spectra spread out over several month in 2012. Unlike for HD 49798, no radial velocity variations were found and, hence, there is no dynamical evidence for the existence of a compact companion yet. The origin of the pulsed X-ray emission remains as a mystery.

Single-pulse enhanced coherent diffraction imaging of bacteria with an X-ray free-electron laser

NASA Astrophysics Data System (ADS)

Fan, Jiadong; Sun, Zhibin; Wang, Yaling; Park, Jaehyun; Kim, Sunam; Gallagher-Jones, Marcus; Kim, Yoonhee; Song, Changyong; Yao, Shengkun; Zhang, Jian; Zhang, Jianhua; Duan, Xiulan; Tono, Kensuke; Yabashi, Makina; Ishikawa, Tetsuya; Fan, Chunhai; Zhao, Yuliang; Chai, Zhifang; Gao, Xueyun; Earnest, Thomas; Jiang, Huaidong

2016-09-01

High-resolution imaging offers one of the most promising approaches for exploring and understanding the structure and function of biomaterials and biological systems. X-ray free-electron lasers (XFELs) combined with coherent diffraction imaging can theoretically provide high-resolution spatial information regarding biological materials using a single XFEL pulse. Currently, the application of this method suffers from the low scattering cross-section of biomaterials and X-ray damage to the sample. However, XFELs can provide pulses of such short duration that the data can be collected using the “diffract and destroy” approach before the effects of radiation damage on the data become significant. These experiments combine the use of enhanced coherent diffraction imaging with single-shot XFEL radiation to investigate the cellular architecture of Staphylococcus aureus with and without labeling by gold (Au) nanoclusters. The resolution of the images reconstructed from these diffraction patterns were twice as high or more for gold-labeled samples, demonstrating that this enhancement method provides a promising approach for the high-resolution imaging of biomaterials and biological systems.

Single-pulse enhanced coherent diffraction imaging of bacteria with an X-ray free-electron laser

PubMed Central

Fan, Jiadong; Sun, Zhibin; Wang, Yaling; Park, Jaehyun; Kim, Sunam; Gallagher-Jones, Marcus; Kim, Yoonhee; Song, Changyong; Yao, Shengkun; Zhang, Jian; Zhang, Jianhua; Duan, Xiulan; Tono, Kensuke; Yabashi, Makina; Ishikawa, Tetsuya; Fan, Chunhai; Zhao, Yuliang; Chai, Zhifang; Gao, Xueyun; Earnest, Thomas; Jiang, Huaidong

2016-01-01

High-resolution imaging offers one of the most promising approaches for exploring and understanding the structure and function of biomaterials and biological systems. X-ray free-electron lasers (XFELs) combined with coherent diffraction imaging can theoretically provide high-resolution spatial information regarding biological materials using a single XFEL pulse. Currently, the application of this method suffers from the low scattering cross-section of biomaterials and X-ray damage to the sample. However, XFELs can provide pulses of such short duration that the data can be collected using the “diffract and destroy” approach before the effects of radiation damage on the data become significant. These experiments combine the use of enhanced coherent diffraction imaging with single-shot XFEL radiation to investigate the cellular architecture of Staphylococcus aureus with and without labeling by gold (Au) nanoclusters. The resolution of the images reconstructed from these diffraction patterns were twice as high or more for gold-labeled samples, demonstrating that this enhancement method provides a promising approach for the high-resolution imaging of biomaterials and biological systems. PMID:27659203

Single-pulse enhanced coherent diffraction imaging of bacteria with an X-ray free-electron laser.

PubMed

Fan, Jiadong; Sun, Zhibin; Wang, Yaling; Park, Jaehyun; Kim, Sunam; Gallagher-Jones, Marcus; Kim, Yoonhee; Song, Changyong; Yao, Shengkun; Zhang, Jian; Zhang, Jianhua; Duan, Xiulan; Tono, Kensuke; Yabashi, Makina; Ishikawa, Tetsuya; Fan, Chunhai; Zhao, Yuliang; Chai, Zhifang; Gao, Xueyun; Earnest, Thomas; Jiang, Huaidong

2016-09-23

High-resolution imaging offers one of the most promising approaches for exploring and understanding the structure and function of biomaterials and biological systems. X-ray free-electron lasers (XFELs) combined with coherent diffraction imaging can theoretically provide high-resolution spatial information regarding biological materials using a single XFEL pulse. Currently, the application of this method suffers from the low scattering cross-section of biomaterials and X-ray damage to the sample. However, XFELs can provide pulses of such short duration that the data can be collected using the "diffract and destroy" approach before the effects of radiation damage on the data become significant. These experiments combine the use of enhanced coherent diffraction imaging with single-shot XFEL radiation to investigate the cellular architecture of Staphylococcus aureus with and without labeling by gold (Au) nanoclusters. The resolution of the images reconstructed from these diffraction patterns were twice as high or more for gold-labeled samples, demonstrating that this enhancement method provides a promising approach for the high-resolution imaging of biomaterials and biological systems.

In situ monitoring of laser-induced periodic surface structures formation on polymer films by grazing incidence small-angle X-ray scattering.

PubMed

Rebollar, Esther; Rueda, Daniel R; Martín-Fabiani, Ignacio; Rodríguez-Rodríguez, Álvaro; García-Gutiérrez, Mari-Cruz; Portale, Giuseppe; Castillejo, Marta; Ezquerra, Tiberio A

2015-04-07

The formation of laser-induced periodic surface structures (LIPSS) on model spin-coated polymer films has been followed in situ by grazing incidence small-angle X-ray scattering (GISAXS) using synchrotron radiation. The samples were irradiated at different repetition rates ranging from 1 up to 10 Hz by using the fourth harmonic of a Nd:YAG laser (266 nm) with pulses of 8 ns. Simultaneously, GISAXS patterns were acquired during laser irradiation. The variation of both the GISAXS signal with the number of pulses and the LIPSS period with laser irradiation time is revealing key kinetic aspects of the nanostructure formation process. By considering LIPSS as one-dimensional paracrystalline lattice and using a correlation found between the paracrystalline disorder parameter, g, and the number of reflections observed in the GISAXS patterns, the variation of the structural order of LIPSS can be assessed. The role of the laser repetition rate in the nanostructure formation has been clarified. For high pulse repetition rates (i.e., 10 Hz), LIPSS evolve in time to reach the expected period matching the wavelength of the irradiating laser. For lower pulse repetition rates LIPSS formation is less effective, and the period of the ripples never reaches the wavelength value. Results support and provide information on the existence of a feedback mechanism for LIPSS formation in polymer films.

Characterization of multilayer coated replicated Wolter optics for imaging x-ray emission from pulsed power

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

Ames, Andrew; Ampleford, David; Bourdon, Chris

Here, we have developed a process for indirectly coating small diameter electroformed nickel replicated optics with multilayers to increase their response at high energy (i.e. >10 keV). The ability to fabricate small diameter multilayer-coated full-shell Wolter X-ray optics with narrow bandpass opens the door to several applications within astronomy and also provides a path for cross-fertilization to other fields. We report on the characterization and evaluation of the first two prototype X-ray Wolter optics to be delivered to the Z Pulsed Power Facility at Sandia National Laboratories. The intent is to develop and field several optics as part of anmore » imaging system with targeted spectral ranges.« less

Characterization of multilayer coated replicated Wolter optics for imaging x-ray emission from pulsed power

DOE PAGES

Ames, Andrew; Ampleford, David; Bourdon, Chris; ...

2017-08-29

Here, we have developed a process for indirectly coating small diameter electroformed nickel replicated optics with multilayers to increase their response at high energy (i.e. >10 keV). The ability to fabricate small diameter multilayer-coated full-shell Wolter X-ray optics with narrow bandpass opens the door to several applications within astronomy and also provides a path for cross-fertilization to other fields. We report on the characterization and evaluation of the first two prototype X-ray Wolter optics to be delivered to the Z Pulsed Power Facility at Sandia National Laboratories. The intent is to develop and field several optics as part of anmore » imaging system with targeted spectral ranges.« less

Characterization of multilayer coated replicated Wolter optics for imaging x-ray emission from pulsed power

NASA Astrophysics Data System (ADS)

Ames, A.; Ampleford, D.; Bourdon, C.; Bruni, R.; Kilaru, K.; Kozioziemski, B.; Pivovaroff, M.; Ramsey, B.; Romaine, S.; Vogel, J.; Walton, C.; Wu, M.

2017-08-01

We have developed a process for indirectly coating arbitrarily small diameter electroformed nickel replicated optics with multilayers to increase their response at high energy (i.e. >10 keV). The ability to fabricate small diameter multilayer coated full shell Wolter X-ray optics with narrow bandpass opens the door to several applications within astronomy and also provides a path for cross-fertilization to other fields. We report on the characterization and evaluation of the first two prototype X-ray Wolter optics to be delivered to the Z Pulsed Power Facility at Sandia National Laboratories. The intent is to develop and field several optics as part of an imaging system with targeted spectral ranges.

Timing Studies of X Persei and the Discovery of Its Transient Quasi-periodic Oscillation Feature

NASA Technical Reports Server (NTRS)

Acuner, Z.; Inam,S. C.; Sahiner, S.; Serim, M. M.; Baykal, A.; Swank, J.

2014-01-01

We present a timing analysis of X Persei (X Per) using observations made between 1998 and 2010 with the Proportional Counter Array (PCA) onboard the Rossi X-ray Timing Explorer (RXTE) and with the INTEGRAL Soft Gamma-Ray Imager (ISGRI). All pulse arrival times obtained from the RXTE-PCA observations are phase-connected and a timing solution is obtained using these arrival times. We update the long-term pulse frequency history of the source by measuring its pulse frequencies using RXTE-PCA and ISGRI data. From the RXTEPCA data, the relation between the frequency derivative and X-ray flux suggests accretion via the companion's stellar wind. However, the detection of a transient quasi-periodic oscillation feature, peaking at approximately 0.2 Hz, suggests the existence of an accretion disc. We find that doublebreak models fit the average power spectra well, which suggests that the source has at least two different accretion flow components dominating the overall flow. From the power spectrum of frequency derivatives, we measure a power-law index of approximately - 1, which implies that, on short time-scales, disc accretion dominates over noise, while on time-scales longer than the viscous time-scales, the noise dominates. From pulse profiles, we find a correlation between the pulse fraction and the count rate of the source.

Optical spectroscopy of the Be/X-ray binary V850 Centauri/GX 304-1 during faint X-ray periodical activity

NASA Astrophysics Data System (ADS)

Malacaria, C.; Kollatschny, W.; Whelan, E.; Santangelo, A.; Klochkov, D.; McBride, V.; Ducci, L.

2017-07-01

Context. Be/X-ray binaries (BeXRBs) are the most populous class of high-mass X-ray binaries. Their X-ray duty cycle is tightly related to the optical companion wind activity, which in turn can be studied through dedicated optical spectroscopic observations. Aims: We study optical spectral features of the Be circumstellar disk to test their long-term variability and their relation with the X-ray activity. Special attention has been given to the Hα emission line, one of the best tracers of the disk conditions. Methods: We obtained optical broadband medium resolution spectra from a dedicated campaign with the Anglo-Australian Telescope and the Southern African Large Telescope in 2014-2015. Data span over one entire binary orbit, and cover both X-ray quiescent and moderately active periods. We used Balmer emission lines to follow the evolution of the circumstellar disk. Results: We observe prominent spectral features, like double-peaked Hα and Hβ emission lines. The HαV/R ratio significantly changes over a timescale of about one year. Our observations are consistent with a system observed at a large inclination angle (I ≳ 60°). The derived circumstellar disk size shows that the disk evolves from a configuration that prevents accretion onto the neutron star, to one that allows only moderate accretion. This is in agreement with the contemporary observed X-ray activity. Our results are interpreted within the context of inefficient tidal truncation of the circumstellar disk, as expected for this source's binary configuration. We derived the Hβ-emitting region size, which is equal to about half of the corresponding Hα-emitting disk, and constrain the luminosity class of V850 Cen as III-V, consistent with the previously proposed class.

A1540-53, an eclipsing X-ray binary pulsator

NASA Technical Reports Server (NTRS)

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

1977-01-01

An eclipsing X-ray binary pulsator consistent with the location of A1540-53 was observed. The source pulse period was 528.93 plus or minus 0.10 seconds. The binary nature is confirmed by a Doppler curve for the pulsation period. The eclipse angle of 30.5 deg plus or minus 3 deg and the 4 h transition to and from eclipse suggest an early type, giant or supergiant, primary star.

Discovery of the 198 s X-Ray Pulsar GRO J2058+42

NASA Technical Reports Server (NTRS)

Wilson, Colleen A.; Finger, Mark H.; Harmon, B. Alan; Chakrabarty, Deepto; Strohmayer, Tod

1997-01-01

GRO J2058+42, a transient 198 second x-ray pulsar, was discovered by the Burst and Transient Source Experiment (BATSE) on the Compton Gamma-Ray Observatory (CGRO), during a "giant" outburst in 1995 September-October. The total flux peaked at about 300 mCrab (20-50 keV) as measured by Earth occultation. The pulse period decreased from 198 s to 196 s during the 46-day outburst. The pulse shape evolved over the course of the outburst and exhibited energy dependent variations. BATSE observed five additional weak outbursts from GRO J2058+427 each with two week duration and peak pulsed flux of about 15 mcrab (20-50 keV), that were spaced by about 110 days. An observation of the 1996 November outburst by the Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) localized the source to within a 4' radius error circle (90% confidence) centered on R.A. = 20 h 59 m.0, Decl. = 41 deg 43 min (J2000). Additional shorter outbursts with peak pulsed fluxes of about 8 mCrab were detected by BATSE halfway between the first four 15 mCrab outbursts. The RXTE All-Sky Monitor detected 8 weak outbursts with approximately equal durations and intensities. GRO J2058+42 is most likely a Be/X-ray binary that appears to outburst at periastron and apastron. No optical counterpart has been identified to date and no x-ray source was present in the error circle in archival ROSAT observations.

Discovery of the 198 Second X-Ray Pulsar GRO J2058+42

NASA Technical Reports Server (NTRS)

Wilson, Colleen A.; Finger, Mark H.; Harmon, B. Alan; Chakrabarty, Deepto; Strohmayer, Tod

1998-01-01

GRO J2058+42, a transient 198 s X-ray pulsar, was discovered by the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO) during a "giant" outburst in 1995 September-October. The total flux peaked at about 300 mcrab (20-50 keV) as measured by Earth occultation. The pulse period decreased from 198 to 196 s during the 46 day outburst. The pulse shape evolved over the course of the outburst and exhibited energy-dependent variations. BATSE observed five additional weak outbursts from GRO J2058 + 42, each with a 2 week duration and a peak-pulsed flux of about 15 mcrab (20-50 keV), that were spaced by about 110 days. An observation of the 1996 November outburst by the Rossi X-Ray Timing Explorer (RXTE) proportional counter array (PCA) localized the source to within a 4 s radius error circle (90% confidence) centered on R.A. = 20h 59m.0, decl. = 41 deg 43 s (J2000). Additional shorter outbursts with peak-pulsed fluxes of about 8 mcrab were detected by BATSE halfway between the first four 15 mcrab outbursts. The RXTE All-Sky Monitor detected all eight weak outbursts with approximately equal durations and intensities. GRO J2058 + 42 is most likely a Be/X-ray binary that appears to outburst at periastron and apastron, No optical counterpart has been identified to date, and no X-ray source was present in the error circle in archival ROSAT observations.

Soft x-ray contact imaging of biological specimens using a laser-produced plasma as an x-ray source

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

Cheng, P.C.

The use of a laser-produced plasma as an x-ray source provides significant advantages over other types of sources for x-ray microradiography of, particularly, living biological specimens. The pulsed nature of the x-rays enables imaging of the specimen in a living state, and the small source size minimizes penumbral blurring. This makes it possible to make an exposure close to the source, thereby increasing the x-ray intensity. In this article, we will demonstrate the applications of x-ray contact microradiography in structural and developmental botany such as the localization of silica deposition and the floral morphologenesis of maize.

Two-colour hard X-ray free-electron laser with wide tunability.

PubMed

Hara, Toru; Inubushi, Yuichi; Katayama, Tetsuo; Sato, Takahiro; Tanaka, Hitoshi; Tanaka, Takashi; Togashi, Tadashi; Togawa, Kazuaki; Tono, Kensuke; Yabashi, Makina; Ishikawa, Tetsuya

2013-01-01

Ultrabrilliant, femtosecond X-ray pulses from X-ray free-electron lasers (XFELs) have promoted the investigation of exotic interactions between intense X-rays and matters, and the observation of minute targets with high spatio-temporal resolution. Although a single X-ray beam has been utilized for these experiments, the use of multiple beams with flexible and optimum beam parameters should drastically enhance the capability and potentiality of XFELs. Here we show a new light source of a two-colour double-pulse (TCDP) XFEL in hard X-rays using variable-gap undulators, which realizes a large and flexible wavelength separation of more than 30% with an ultraprecisely controlled time interval in the attosecond regime. Together with sub-10-fs pulse duration and multi-gigawatt peak powers, the TCDP scheme enables us to elucidate X-ray-induced ultrafast transitions of electronic states and structures, which will significantly contribute to the advancement of ultrafast chemistry, plasma and astronomical physics, and quantum X-ray optics.

X-Ray Pulsar Studies With RXTE

NASA Technical Reports Server (NTRS)

Rappaport, Saul

2004-01-01

Our activities here at MIT have largely concentrated on four different binary X-ray pulsars: LMC X-4; 4UO352+3O/XPer; 4U0115+63; and X1908+075. We have also recently initiated a search for millisecond X-ray pulsations in RXTE archival data for several bright LMXBs using a new technique. Since this study is just getting under way, we will not report any results here. Using RXTE timing observations of LMC X-4 we have definitively measured, for the first time, the orbital decay of this high-mass X-ray binary. The e-folding decay time scale is very close to lo6 years, comparable to, but somewhat longer than, the corresponding orbital decay times for SMC X-1 and Cen X-3. We find that the orbital decay in LMC X-4 is likely driven by tidal interactions, where the asynchronism between the orbital motion and the rotation of the companion star is maintained by the evolutionary expansion of the companion. Under NASA grant NAGS7479 we carried out RXTE observations of X Per/4U0352+30 in order to track the pulse phase over a one year interval. This effort was successful in tentatively identifying a N 250-day orbital period. However, due to the fact that the observing interval was only somewhat longer than the orbital period, we asked for the observations of X Per to continue as public, or non-proprietary observations. Dr. Jean Swank kindly agreed to the continuation of the observations and they were carried out on a less frequent basis over the next year and a half. After 72 separate observations of X Per, we have the orbital period and semimajor axis firmly determined. In addition, we were able to measure the orbital eccentricity-which turns out to be remarkably small (e = 0.10) for such a wide binary orbit. This has led us establish the birth of a neutron star with a very small (or zero) natal kick.

Few-femtosecond time-resolved measurements of X-ray free-electron lasers.

PubMed

Behrens, C; Decker, F-J; Ding, Y; Dolgashev, V A; Frisch, J; Huang, Z; Krejcik, P; Loos, H; Lutman, A; Maxwell, T J; Turner, J; Wang, J; Wang, M-H; Welch, J; Wu, J

2014-04-30

X-ray free-electron lasers, with pulse durations ranging from a few to several hundred femtoseconds, are uniquely suited for studying atomic, molecular, chemical and biological systems. Characterizing the temporal profiles of these femtosecond X-ray pulses that vary from shot to shot is not only challenging but also important for data interpretation. Here we report the time-resolved measurements of X-ray free-electron lasers by using an X-band radiofrequency transverse deflector at the Linac Coherent Light Source. We demonstrate this method to be a simple, non-invasive technique with a large dynamic range for single-shot electron and X-ray temporal characterization. A resolution of less than 1 fs root mean square has been achieved for soft X-ray pulses. The lasing evolution along the undulator has been studied with the electron trapping being observed as the X-ray peak power approaches 100 GW.

Cosmic x ray physics

NASA Technical Reports Server (NTRS)

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

1991-01-01

The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

Modeling the performance of a photon counting x-ray detector for CT: Energy response and pulse pileup effects

PubMed Central

Taguchi, Katsuyuki; Zhang, Mengxi; Frey, Eric C.; Wang, Xiaolan; Iwanczyk, Jan S.; Nygard, Einar; Hartsough, Neal E.; Tsui, Benjamin M. W.; Barber, William C.

2011-01-01

Purpose: Recently, photon counting x-ray detectors (PCXDs) with energy discrimination capabilities have been developed for potential use in clinical computed tomography (CT) scanners. These PCXDs have great potential to improve the quality of CT images due to the absence of electronic noise and weights applied to the counts and the additional spectral information. With high count rates encountered in clinical CT, however, coincident photons are recorded as one event with a higher or lower energy due to the finite speed of the PCXD. This phenomenon is called a “pulse pileup event” and results in both a loss of counts (called “deadtime losses”) and distortion of the recorded energy spectrum. Even though the performance of PCXDs is being improved, it is essential to develop algorithmic methods based on accurate models of the properties of detectors to compensate for these effects. To date, only one PCXD (model DXMCT-1, DxRay, Inc., Northridge, CA) has been used for clinical CT studies. The aim of that study was to evaluate the agreement between data measured by DXMCT-1 and those predicted by analytical models for the energy response, the deadtime losses, and the distorted recorded spectrum caused by pulse pileup effects. Methods: An energy calibration was performed using 99mTc (140 keV), 57Co (122 keV), and an x-ray beam obtained with four x-ray tube voltages (35, 50, 65, and 80 kVp). The DXMCT-1 was placed 150 mm from the x-ray focal spot; the count rates and the spectra were recorded at various tube current values from 10 to 500 μA for a tube voltage of 80 kVp. Using these measurements, for each pulse height comparator we estimated three parameters describing the photon energy-pulse height curve, the detector deadtime τ, a coefficient k that relates the x-ray tube current I to an incident count rate a by a=k×I, and the incident spectrum. The mean pulse shape of all comparators was acquired in a separate study and was used in the model to estimate the

XTE J1946+274: An Enigmatic X-Ray Pulsar

NASA Technical Reports Server (NTRS)

Wilson, Colleen A.; Finger, Mark H.; Coe, M. J.; Negueruela, Ignacio; Six, N. Frank (Technical Monitor)

2002-01-01

XTE J1946+274 = GRO J1944+26 is a 15.8-s X-ray pulsar discovered simultaneously by the Rossi X-ray Timing Explorer (RXTE) and the Burst and Transient Source Experiment (BATSE) in September 1998. Follow-up optical/IR observations resulted in the discovery of a Be star companion. Our pulse timing analysis of BATSE and RXTE data indicates that the orbital period is approximately 169 days. Since its discovery in 1998, XTE J1946+274 has undergone 13 outbursts. These outbursts axe not regularly spaced. They occur approximately twice per orbit and are not locked in orbital phase, unlike most Be/X-ray transient systems. A possible explanation for this is a global-one armed oscillation or density perturbation propagating rapidly in the Be star's disk. We will investigate radial velocity variations in the central peak of the H-alpha line to look for evidence of such a perturbation. From 2001 March-September, we regularly monitored XTE J1946+274 with the RXTE PCA. We will demonstrate that the spectrum appears to be varying with orbital phase, based on the 2001 and 1998 RXTE PCA observations. We will also present histories of pulsed frequency and flux.

Explosives detection using photoneutrons produced by X-rays

NASA Astrophysics Data System (ADS)

Yang, Yigang; Li, Yuanjing; Wang, Haidong; Li, Tiezhu; Wu, Bin

2007-08-01

The detection of explosives has become a critical issue after recent terrorist attacks. This paper describes research on explosives detection using photoneutrons from a photoneutron convertor that consists of 20 kg heavy water in an aluminum container whose shape was optimized to most effectively convert X-rays to photoneutrons. The X-rays were produced by a 9 MeV electron accelerator with an average electron current of 100 μA, resulted in a photoneutron yield of >10 11 n/s. Monte-Carlo simulations show that the radiation field is composed of X-ray pulses, fast neutron pulses and thermal neutrons. Both the X-ray and fast neutron pulses are 5 μs wide with a 300 Hz repetition frequency. The thermal neutron flux, which is higher than 10 4 n/cm 2/s, is essentially time invariant. A time shielding circuit was developed for the spectrometry system to halt the sampling process during the intense X-ray pulses. Paraffin, boron carbide and lead were used to protect the detector from interference from the X-rays, fast neutrons, thermal neutrons and background γ-rays coming from the system materials induced by photoneutrons. 5″×5″ NaI (Tl) scintillators were chosen as the detectors to detect the photoneutrons induced γ-rays from the inspected explosive simulant. Nitrogen (6.01 cps) 10.828 MeV γ-rays were detected with one detector from a 50 kg carbamide block placed 60 cm in front of the detector. A collimator was used to reduce the number of background 10.828 MeV γ-rays coming from the nitrogen in the air to improve the signal to background ratio from 0.136 to 1.81. A detector array of seven 5″×5″ NaI (Tl) detectors was used to measure the 2-D distributions of N and H in the sample. The combination of photoneutron analysis and X-ray imaging shows promise for enhancing explosives detection capabilities.

Hercules X-1: Spectral Variability of an X-Ray Pulsar in a Stellar Binary System. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Pravdo, S. H.

1976-01-01

A cosmic X-ray spectroscopy experiment onboard the Orbiting Solar Observatory 8 (OSO-8), observed Her x-1 continuously for approximately 8 days. Spectral-temporal correlations of the X-ray emission were obtained. The major results concern observations of: (1) iron band emission, (2) spectral hardening (increase in effective x-ray temperature) within the X-ray pulse, and (3) a transition from an X-ray low state to a high state. The spectrum obtained prior to the high state can be interpreted as reflected emission from a hot coronal gas surrounding an accretion disk, which itself shields the primary X-ray source from the line of sight during the low state. The spectral hardening within the X-ray pulse was indicative of the beaming mechanism at the neutron star surface. The hardest spectrum by pulse phase was identified with the line of sight close to the Her x-1 magnetic dipole axis, and the X-ray pencil beam become harder with decreasing angle between the line of sight and the dipole axis.

Dilation x-ray imager a new∕faster gated x-ray imager for the NIF.

PubMed

Nagel, S R; Hilsabeck, T J; Bell, P M; Bradley, D K; Ayers, M J; Barrios, M A; Felker, B; Smith, R F; Collins, G W; Jones, O S; Kilkenny, J D; Chung, T; Piston, K; Raman, K S; Sammuli, B; Hares, J D; Dymoke-Bradshaw, A K L

2012-10-01

As the yield on implosion shots increases it is expected that the peak x-ray emission reduces to a duration with a FWHM as short as 20 ps for ∼7 × 10(18) neutron yield. However, the temporal resolution of currently used gated x-ray imagers on the NIF is 40-100 ps. We discuss the benefits of the higher temporal resolution for the NIF and present performance measurements for dilation x-ray imager, which utilizes pulse-dilation technology [T. J. Hilsabeck et al., Rev. Sci. Instrum. 81, 10E317 (2010)] to achieve x-ray imaging with temporal gate times below 10 ps. The measurements were conducted using the COMET laser, which is part of the Jupiter Laser Facility at the Lawrence Livermore National Laboratory.

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

NASA Technical Reports Server (NTRS)

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

2013-01-01

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

Outbursts from the Transient X-Ray Pulsar Cep X-4 (GS 2138+56)

NASA Technical Reports Server (NTRS)

Wilson, Colleen A.; Finger, Mark H.; Scott, D. Matthew

1997-01-01

Cep X-4 was discovered with the Orbiting Solar Observatory (OSO) 7 Satellite in 1973 June-July, but no pulsations were detected. In March 1988, an additional outburst was observed with Gingaq. Pulsations at a period of 66.2490 +/- .0001 s were detected during a month long outburst which peaked at about 100 mCrab (1-20 keV) in early April 1988. The source apparently did not appear again until June 1993 when it was detected by Roentgen Satellite (ROSAT) and Burst and Transient Source Experiment (BATSE). Pulsations at a period of 66.2499 +/- .0007 s were detected by BATSE. The outburst lasted about two weeks and had a peak pulsed flux of 15-20 mCrab (20-50 keV). In July 1997, BATSE and the All-Sky Monitor (ASM) on Rossi X-ray Timing Explorer (RXTE) observed a new outburst from Cep X-4. Pulsations at a period of 66.2743 +/- 0.0005 s were detected by BATSE. This outburst lasted about 2 weeks and peaked at a pulsed flux of about 10-15 mCrab (20-50 keV). Results of a search of BATSE data for additional outbursts will be presented. Pulse frequency and flux histories will be presented and compared to the flux history from the RXTE ASM. Implications of the apparent spin-down between outbursts will be discussed.

IGR J170626143 is an Accreting Millisecond X-Ray Pulsar

NASA Technical Reports Server (NTRS)

Strohmayer, Tod E.; Keek, Laurens

2017-01-01

We present the discovery of 163.65 Hz X-ray pulsations from IGR J17062-6143 in the only observation obtained from the source with the Rossi X-ray Timing Explorer. This detection makes IGR J17062-6143 the lowest frequency accreting millisecond X-ray pulsar presently known. The pulsations are detected in the 2-12 keV band with an overall significance of 4.3sigma and an observed pulsed amplitude of 5.54% +/-0.67% (in this band). Both dynamic power spectral and coherent phase timing analysis indicate that the pulsation frequency is decreasing during the approx. =1.2 ks observation in a manner consistent with orbital motion of the neutron star. Because the observation interval is short, we cannot precisely measure the orbital period; however, periods shorter than 17 minutes are excluded at 90% confidence. For the range of acceptable circular orbits the inferred binary mass function substantially overlaps the observed range for the AMXP population as a whole.

CAN THE SUBSONIC ACCRETION MODEL EXPLAIN THE SPIN PERIOD DISTRIBUTION OF WIND-FED X-RAY PULSARS?

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

Li, Tao; Shao, Yong; Li, Xiang-Dong, E-mail: lixd@nju.edu.cn

Neutron stars in high-mass X-ray binaries (HMXBs) generally accrete from the wind matter of their massive companion stars. Recently, Shakura et al. suggested a subsonic accretion model for low-luminosity (<4 × 10{sup 36} erg s{sup −1}), wind-fed X-ray pulsars. To test the feasibility of this model, we investigate the spin period distribution of wind-fed X-ray pulsars with a supergiant companion star, using a population synthesis method. We find that the modeled distribution of supergiant HMXBs in the spin period–orbital period diagram is consistent with observations, provided that the winds from the donor stars have relatively low terminal velocities (≲1000 kmmore » s{sup −1}). The measured wind velocities in several supergiant HMXBs seem to favor this viewpoint. The predicted number ratio of wind-fed X-ray pulsars with persistent X-ray luminosities that are higher and lower than 4 × 10{sup 36} erg s{sup −1} is about 1:10.« less

Laser-driven powerful kHz hard x-ray source

NASA Astrophysics Data System (ADS)

Li, Minghua; Huang, Kai; Chen, Liming; Yan, Wenchao; Tao, Mengze; Zhao, Jiarui; Ma, Yong; Li, Yifei; Zhang, Jie

2017-08-01

A powerful hard x-ray source based on laser plasma interaction is developed. By introducing the kHz, 800 nm pulses onto a rotating molybdenum (Mo) disk target, intense Mo Kα x-rays are emitted with suppressed bremsstrahlung background. Results obtained with different laser intensities suggest that the dominant absorption mechanism responsible for the high conversion efficiency is vacuum heating (VH). The high degree of spatial coherence is verified. With the high average flux and a source size comparable to the laser focus spot, absorption contrast imaging and phase contrast imaging are carried out to test the imaging capability of the source. Not only useful for imaging application, this compact x-ray source is also holding great potential for ultrafast x-ray diffraction (XRD) due to the intrinsic merits such as femtosecond pulse duration and natural synchronization with the driving laser pulses.

Stimulated resonant x-ray Raman scattering with incoherent radiation

NASA Astrophysics Data System (ADS)

Weninger, Clemens; Rohringer, Nina

2013-11-01

We present a theoretical study on stimulated electronic Raman scattering in neon by resonant excitation with an x-ray free electron laser (XFEL). This study is in support of the recent experimental demonstration [C. Weninger , Phys. Rev. Lett. (to be published)] of stimulated x-ray Raman scattering. Focusing the broadband XFEL pulses into a cell of neon gas at atmospheric pressure a strong inelastic x-ray scattering signal in the forward direction was observed, as the x-ray energy was varied across the region of core-excited Rydberg states and the K edge. The broadband and intrinsically incoherent x-ray pulses from the XFEL lead to a rich, structured line shape of the scattered radiation. We present a generalized Maxwell-Liouville-von Neumann approach to self-consistently solve for the amplification of the scattered radiation along with the time evolution of the density matrix of the atomic and residual ionic system. An in-depth analysis of the evolution of the emission spectra as a function of the Raman gain is presented. Furthermore, we propose the use of statistical methods to obtain high-resolution scattering data beyond the lifetime broadening despite pumping with incoherent x-ray pulses.

Black holes in short period X-ray binaries and the transition to radiatively inefficient accretion

NASA Astrophysics Data System (ADS)

Knevitt, G.; Wynn, G. A.; Vaughan, S.; Watson, M. G.

2014-02-01

By comparing the orbital period distributions of black hole and neutron star low-mass X-ray binaries (LMXBs) in the Ritter-Kolb catalogue we show that there is statistical evidence for a dearth of black hole systems at short orbital periods (Porb < 4 h). This could either be due to a true divergence in orbital period distributions of these two types of system, or to black hole LMXBs being preferentially hidden from view at short orbital periods. We explore the latter possibility, by investigating whether black hole LMXBs could be concealed by a switch to radiatively inefficient accretion at low luminosities. The peak luminosity and the duration of X-ray binary outbursts are related to the disc radius and, hence, the orbital period. At short periods, where the peak outburst luminosity drops close to the threshold for radiatively inefficient accretion, black hole LMXBs have lower outburst luminosities, shorter outburst durations and lower X-ray duty cycles than comparable neutron star systems. These factors can combine to severely reduce the detection probability of short period black hole LMXBs relative to those containing neutron stars. We estimate the outburst properties and orbital period distribution of black hole LMXBs using two models of the transition to radiatively inefficient accretion: an instantaneous drop in accretion efficiency (η) to zero, at a fraction (f) of the Eddington luminosity (LEdd) and a power-law efficiency decrease, η ∝ dot{M}^n, for L < f LEdd. We show that a population of black hole LMXBs at short orbital periods can only be hidden by a sharp drop in efficiency, either instantaneous or for n ≳ 3. This could be achieved by a genuine drop in luminosity or through abrupt spectral changes that shift the accretion power out of a given X-ray band.

Ultrafast X-Ray Coherent Control

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

Reis, David

2009-05-01

This main purpose of this grant was to develop the nascent eld of ultrafast x-ray science using accelerator-based sources, and originally developed from an idea that a laser could modulate the di racting properties of a x-ray di racting crystal on a fast enough time scale to switch out in time a shorter slice from the already short x-ray pulses from a synchrotron. The research was carried out primarily at the Advanced Photon Source (APS) sector 7 at Argonne National Laboratory and the Sub-Picosecond Pulse Source (SPPS) at SLAC; in anticipation of the Linac Coherent Light Source (LCLS) x-ray freemore » electron laser that became operational in 2009 at SLAC (all National User Facilities operated by BES). The research centered on the generation, control and measurement of atomic-scale dynamics in atomic, molecular optical and condensed matter systems with temporal and spatial resolution . It helped develop the ultrafast physics, techniques and scienti c case for using the unprecedented characteristics of the LCLS. The project has been very successful with results have been disseminated widely and in top journals, have been well cited in the eld, and have laid the foundation for many experiments being performed on the LCLS, the world's rst hard x-ray free electron laser.« less

Repetitive flash x-ray generator operated at low-dose rates for a medical x-ray television system

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Isobe, Hiroshi; Takahashi, Kei; Tamakawa, Yoshiharu; Yanagisawa, Toru

1991-04-01

The fundamental studies for the repetitive flash x-ray generator operated at lowdose rates for a medical x-ray television system are described. This x-ray generator consisted of the following components: a high-voltage power supply, an energy storage condenser of lOOnF, a coaxial cable condenser with a capacity of l000pF, a repetitive impulse switching system, a turbo molecular pump, and an x-ray tube having a cold cathode. The condenser was charged from 40 to 70kV by a power supply, and the electric charges stored in the condenser were discharged repetitively by using a trigger electrode operated by an impulse switching system. The x-ray tube was of the triode-type which was connected to the turbo molecular pump and had a large discharge impedance in order to prevent the damped oscillations of the tube current and voltage. The maximum tube voltage was equivalent to the initial charged voltage, and the peak current was less than 70A. The durations were about 2ps, and the x-ray intensities were less than 1. OpC/kg at 0. 5m per pulse. The repetition frequency was less than 50Hz, and the effective focal spot size was equivalent to the anode diameter of 3. 0mm. For the x-ray television system used in conjunction with this repetitive pulsed x-ray generator, since the electromagnetic noise primarily caused by the high tube current was decreased, noise-free stroboscopic radiography performed by the television system could be realized.

X-ray beamsplitter

DOEpatents

Ceglio, Natale M.; Stearns, Daniel S.; Hawryluk, Andrew M.; Barbee, Jr., Troy W.

1989-01-01

An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5-50 pairs of alternate Mo/Si layers with a period of 20-250 A. The support membrane is 10-200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window.

The PoGO+ view on Crab off-pulse hard X-ray polarization

NASA Astrophysics Data System (ADS)

Chauvin, M.; Florén, H.-G.; Friis, M.; Jackson, M.; Kamae, T.; Kataoka, J.; Kawano, T.; Kiss, M.; Mikhalev, V.; Mizuno, T.; Tajima, H.; Takahashi, H.; Uchida, N.; Pearce, M.

2018-06-01

The linear polarization fraction (PF) and angle of the hard X-ray emission from the Crab provide unique insight into high-energy radiation mechanisms, complementing the usual imaging, timing, and spectroscopic approaches. Results have recently been presented by two missions operating in partially overlapping energy bands, PoGO+ (18-160 keV) and AstroSat CZTI (100-380 keV). We previously reported PoGO+ results on the polarization parameters integrated across the light curve and for the entire nebula-dominated off-pulse region. We now introduce finer phase binning, in light of the AstroSat CZTI claim that the PF varies across the off-pulse region. Since both missions are operating in a regime where errors on the reconstructed polarization parameters are non-Gaussian, we adopt a Bayesian approach to compare results from each mission. We find no statistically significant variation in off-pulse polarization parameters, neither when considering the mission data separately nor when they are combined. This supports expectations from standard high-energy emission models.

Performance Assessment of Different Pulse Reconstruction Algorithms for the ATHENA X-Ray Integral Field Unit

NASA Technical Reports Server (NTRS)

Peille, Phillip; Ceballos, Maria Teresa; Cobo, Beatriz; Wilms, Joern; Bandler, Simon; Smith, Stephen J.; Dauser, Thomas; Brand, Thorsten; Den Haretog, Roland; de Plaa, Jelle;

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.

Observation of Reverse Saturable Absorption of an X-ray Laser

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

Cho, B. I.; Cho, M. S.; Kim, M.

A nonlinear absorber in which the excited state absorption is larger than the ground state can undergo a process called reverse saturable absorption. It is a well-known phenomenon in laser physics in the optical regime, but is more difficult to generate in the x-ray regime, where fast nonradiative core electron transitions typically dominate the population kinetics during light matter interactions. Here, we report the first observation of decreasing x-ray transmission in a solid target pumped by intense x-ray free electron laser pulses. The measurement has been made below the K-absorption edge of aluminum, and the x-ray intensity ranges are 10more » 16 –10 17 W=cm 2. It has been confirmed by collisional radiative population kinetic calculations, underscoring the fast spectral modulation of the x-ray pulses and charge states relevant to the absorption and transmission of x-ray photons. The processes shown through detailed simulations are consistent with reverse saturable absorption, which would be the first observation of this phenomena in the x-ray regime. These light matter interactions provide a unique opportunity to investigate optical transport properties in the extreme state of matters, as well as affording the potential to regulate ultrafast x-ray freeelectron laser pulses.« less

Observation of Reverse Saturable Absorption of an X-ray Laser

DOE PAGES

Cho, B. I.; Cho, M. S.; Kim, M.; ...

2017-08-16

A nonlinear absorber in which the excited state absorption is larger than the ground state can undergo a process called reverse saturable absorption. It is a well-known phenomenon in laser physics in the optical regime, but is more difficult to generate in the x-ray regime, where fast nonradiative core electron transitions typically dominate the population kinetics during light matter interactions. Here, we report the first observation of decreasing x-ray transmission in a solid target pumped by intense x-ray free electron laser pulses. The measurement has been made below the K-absorption edge of aluminum, and the x-ray intensity ranges are 10more » 16 –10 17 W=cm 2. It has been confirmed by collisional radiative population kinetic calculations, underscoring the fast spectral modulation of the x-ray pulses and charge states relevant to the absorption and transmission of x-ray photons. The processes shown through detailed simulations are consistent with reverse saturable absorption, which would be the first observation of this phenomena in the x-ray regime. These light matter interactions provide a unique opportunity to investigate optical transport properties in the extreme state of matters, as well as affording the potential to regulate ultrafast x-ray freeelectron laser pulses.« less

500-MHz x-ray counting with a Si-APD and a fast-pulse processing system

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

Kishimoto, Shunji; Taniguchi, Takashi; Tanaka, Manobu

2010-06-23

We introduce a counting system of up to 500 MHz for synchrotron x-ray high-rate measurements. A silicon avalanche photodiode detector was used in the counting system. The fast-pulse circuit of the amplifier was designed with hybrid ICs to prepare an ASIC system for a large-scale pixel array detector in near future. The fast amplifier consists of two cascading emitter-followers using 10-GHz band transistors. A count-rate of 3.25x10{sup 8} s{sup -1} was then achieved using the system for 8-keV x-rays. However, a baseline shift by adopting AC-coupling in the amplifier disturbed us to observe the maximum count of 4.49x10{sup 8} s{supmore » -1}, determined by electron-bunch filling into a ring accelerator. We also report that an amplifier with a baseline restorer was tested in order to keep the baseline level to be 0 V even at high input rates.« less

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

NASA Technical Reports Server (NTRS)

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

1978-01-01

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

Observation of Betatron X-Ray Radiation in a Self-Modulated Laser Wakefield Accelerator Driven with Picosecond Laser Pulses

DOE PAGES

Albert, F.; Lemos, N.; Shaw, J. L.; ...

2017-03-31

We investigate a new regime for betatron x-ray emission that utilizes kilojoule-class picosecond lasers to drive wakes in plasmas. When such laser pulses with intensities of ~ 5 × 1 0 18 W / cm 2 are focused into plasmas with electron densities of ~ 1 × 1 0 19 cm - 3 , they undergo self-modulation and channeling, which accelerates electrons up to 200 MeV energies and causes those electrons to emit x rays. The measured x-ray spectra are fit with a synchrotron spectrum with a critical energy of 10–20 keV, and 2D particle-in-cell simulations were used to modelmore » the acceleration and radiation of the electrons in our experimental conditions« less

Pulse-phase dependence of emission lines in the X-ray pulsar 4U 1626-67

NASA Astrophysics Data System (ADS)

Beri, Aru; Paul, Biswajit; Dewangan, Gulab C.

2015-07-01

We present results from a pulse-phase-resolved spectroscopy of the complex emission lines around 1 keV in the unique accretion-powered X-ray pulsar 4U 1626-67, using the observation made with XMM-Newton in 2003. In this source, the redshifted and blueshifted emission lines and the linewidths measured earlier with Chandra suggest their accretion-disc origin. Another possible signature of lines produced in the accretion disc can be a modulation of the line strength with the pulse phase. We have found that the line fluxes have pulse-phase dependence, making 4U 1626-67 only the second pulsar after Hercules X-1 to show such variability. The O VII line at 0.568 keV from 4U 1626-67 varied by a factor of ˜4, stronger than the continuum variability, which supports the accretion-disc origin. The line flux variability can appear due to variable illumination of the accretion disc by the pulsar or, more likely, a warp-like structure in the accretion disc. We also discuss some further possible diagnostics of the accretion disc in 4U 1626-67 with pulse-phase-resolved emission-line spectroscopy.

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.

X-ray beamsplitter

DOEpatents

Ceglio, N.M.; Stearns, D.G.; Hawryluk, A.M.; Barbee, T.W. Jr.

1987-08-07

An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5--50 pairs of alternate Mo/Si layers with a period of 20--250 A. The support membrane is 10--200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window. 6 figs.

A unified lense-thirring precession model for optical and X-ray quasi-periodic oscillations in black hole binaries

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

Veledina, Alexandra; Poutanen, Juri; Ingram, Adam, E-mail: alexandra.veledina@oulu.fi, E-mail: juri.poutanen@oulu.fi

2013-12-01

Recent observations of accreting black holes reveal the presence of quasi-periodic oscillations (QPO) in the optical power density spectra. The corresponding oscillation periods match those found in X-rays, implying a common origin. Among the numerous suggested X-ray QPO mechanisms, some may also work in the optical. However, their relevance to the broadband—optical through X-ray—spectral properties have not been investigated. For the first time, we discuss the QPO mechanism in the context of the self-consistent spectral model. We propose that the QPOs are produced by Lense-Thirring precession of the hot accretion flow, whose outer parts radiate in optical wavelengths. At themore » same time, its innermost parts are emitting X-rays, which explains the observed connection of QPO periods. We predict that the X-ray and optical QPOs should be either in phase or shifted by half a period, depending on the observer position. We investigate the QPO harmonic content and find that the variability amplitudes at the fundamental frequency are larger in the optical, while the X-rays are expected to have strong harmonics. We then discuss the QPO spectral dependence and compare the expectations to the existing data.« less

Talbot-Lau X-ray Deflectometer electron density diagnostic for laser and pulsed power high energy density plasma experiments

DOE PAGES

Valdivia, M. P.; Stutman, D.; Stoeckl, C.; ...

2016-04-21

Talbot-Lau X-ray Deflectometry has been developed as an electron density diagnostic for High Energy Density plasmas. The technique can deliver x-ray refraction, attenuation, elemental composition, and scatter information from a single Moiré image. An 8 keV Talbot-Lau interferometer was deployed using laser and x-pinch backlighters. Grating survival and electron density mapping was demonstrated for 25-29 J, 8-30 ps laser pulses using copper foil targets. Moire pattern formation and grating survival was also observed using a copper x-pinch driven at 400 kA, ~1 kA/ns. Lastly, these results demonstrate the potential of TXD as an electron density diagnostic for HED plasmas.

Characterization of x-ray framing cameras for the National Ignition Facility using single photon pulse height analysis.

PubMed

Holder, J P; Benedetti, L R; Bradley, D K

2016-11-01

Single hit pulse height analysis is applied to National Ignition Facility x-ray framing cameras to quantify gain and gain variation in a single micro-channel plate-based instrument. This method allows the separation of gain from detectability in these photon-detecting devices. While pulse heights measured by standard-DC calibration methods follow the expected exponential distribution at the limit of a compound-Poisson process, gain-gated pulse heights follow a more complex distribution that may be approximated as a weighted sum of a few exponentials. We can reproduce this behavior with a simple statistical-sampling model.

Stimulated Electronic X-Ray Raman Scattering

NASA Astrophysics Data System (ADS)

Weninger, Clemens; Purvis, Michael; Ryan, Duncan; London, Richard A.; Bozek, John D.; Bostedt, Christoph; Graf, Alexander; Brown, Gregory; Rocca, Jorge J.; Rohringer, Nina

2013-12-01

We demonstrate strong stimulated inelastic x-ray scattering by resonantly exciting a dense gas target of neon with femtosecond, high-intensity x-ray pulses from an x-ray free-electron laser (XFEL). A small number of lower energy XFEL seed photons drive an avalanche of stimulated resonant inelastic x-ray scattering processes that amplify the Raman scattering signal by several orders of magnitude until it reaches saturation. Despite the large overall spectral width, the internal spiky structure of the XFEL spectrum determines the energy resolution of the scattering process in a statistical sense. This is demonstrated by observing a stochastic line shift of the inelastically scattered x-ray radiation. In conjunction with statistical methods, XFELs can be used for stimulated resonant inelastic x-ray scattering, with spectral resolution smaller than the natural width of the core-excited, intermediate state.

X-Ray Simulator Theory Support

DTIC Science & Technology

1993-11-01

the pulse power elements in existing and future DNA flash x-ray simulators, in particular DECADE. The pulse power for this machine is based on...usually requires usage at less than the radiation the longer the radiation pulse. full power . Energy delivered to the plasma load is converted into...on the Proto II generator sured with ap-i-n diode filtered with 25 pm ofaluminum; the TABLE 1. Nominal parameters for some pulse power generators used

Method for efficient, narrow-bandwidth, laser compton x-ray and gamma-ray sources

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

Barty, Christopher P. J.

A method of x-ray and gamma-ray generation via laser Compton scattering uses the interaction of a specially-formatted, highly modulated, long duration, laser pulse with a high-frequency train of high-brightness electron bunches to both create narrow bandwidth x-ray and gamma-ray sources and significantly increase the laser to Compton photon conversion efficiency.

The X-ray monitoring of the long-period colliding wind binaries

NASA Astrophysics Data System (ADS)

Sugawara, Y.; Maeda, Y.; Tsuboi, Y.

2017-10-01

We present the first results from XMM-Newton and Swift observations of two long-period colliding wind binaries WR19 and WR125 around periastron passages. Mass-loss is one of the most important and uncertain parameters in the evolution of a massive star. The X-ray spectrum off the colliding wind binary is the best measure of conditions in the hot postshock gas. By monitoring the changing of the X-ray luminosity and column density along with the orbital phases, we derive the mass-loss rates of these stars. It is known that WR19 (WC5+O9; P=10.1 yr) and WR125 (WC7+O9; P> 24.3 yr) are the dust-making binaries. Each periastron is expected to come in 2016-2017. Since 2016, we carry out on-going monitoring campaigns of WR19 and WR125 with XMM-Newton and Swift. On these observations, the X-rays from WR19 and WR125 were detected for the first time. In the case of WR19, as periastron approached, the column density increased, which indicates that the emission from the wind-wind collision plasma was absorbed by the dense Wolf-Rayet wind.

Apparatus and method to enhance X-ray production in laser produced plasmas

DOEpatents

Augustoni, A.L.; Gerardo, J.B.; Raymond, T.D.

1992-12-29

Method and apparatus for generating x-rays for use in, for instance, x-ray photolithography is disclosed. The method of generating x-rays includes the steps of providing a target and irradiating the target with a laser system which produces a train of sub-pulses to generate an x-ray producing plasma. The sub-pulses are of both high intensity and short duration. The apparatus for generating x-rays from a plasma includes a vacuum chamber, a target supported within the chamber and a laser system, including a short storage time laser. 8 figs.

Apparatus and method to enhance X-ray production in laser produced plasmas

DOEpatents

Augustoni, Arnold L.; Gerardo, James B.; Raymond, Thomas D.

1992-01-01

Method and apparatus for generating x-rays for use in, for instance, x-ray photolithography. The method of generating x-rays includes the steps of providing a target and irradiating the target with a laser system which produces a train of sub-pulses to generate an x-ray producing plasma. The sub-pulses are of both high intensity and short duration. The apparatus for generating x-rays from a plasma includes a vacuum chamber, a target supported within the chamber and a laser system, including a short storage time laser.

X-Ray and Optical Observations of A 0535+26

NASA Technical Reports Server (NTRS)

Camero-Arranz, A.; Finger, M. H.; Wilson-Hodge, C. A.; Jenke, P.; Steele, I.; Coe, M. J.; Gutierrez-Soto, J.; Kretschmar, P.; Caballero, I.; Yan, J.;

A 149 min periodicity underlies the X-ray flaring of Sgr A*

NASA Astrophysics Data System (ADS)

Leibowitz, Elia

2018-03-01

In a paper in 2017, I have shown that 39 large X-ray flares of Sgr A* that were recorded by Chandra observatory in the year 2012 are concentrated preferably around tick marks of an equi-distance grid on the time axis. The period of this grid as found in that paper is 0.1033 d. In this work I show that the effect can be found among all the large X-ray flares recorded by Chandra and XMM - Newton along 15 yr. The mid-points of all the 71 large flares recorded between years 2000 and 2014 are also tightly grouped around tick marks of a grid with this period, or more likely, 0.1032 d. This result is obtained with a confidence level of at least 3.27σ and very likely of 4.62σ. I find also a possible hint that a similar grid is underlying IR flares of the object. I suggest that the pacemaker in the occurrences of the large X-ray flares of Sgr A* is a mass of the order of a low-mass star or a small planet, in a slightly eccentric Keplerian orbit around the SMBH at the centre of the Galaxy. The radius of this orbit is about 6.6 Schwarzschild radii of the BH.

Ultrashort x-ray backlighters and applications

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

Umstadter, D., University of Michigan

Previously, using ultrashort laser pulses focused onto solid targets, we have experimentally studied a controllable ultrafast broadband radiation source in the extreme ultraviolet for time-resolved dynamical studies in ultrafast science [J. Workman, A. Maksimchuk, X. Llu, U. Ellenberger, J. S. Coe, C.-Y. Chien, and D. Umstadter, ``Control of Bright Picosecond X-Ray Emission from Intense Sub- Picosecond Laser-Plasma Interactions,`` Phys. Rev. Lett. 75, 2324 (1995)]. Once armed with a bright ultrafast broadband continuum x-ray source and appropriate detectors, we used the source as a backlighter to study a remotely produced plasma. The application of the source to a problem relevant tomore » high-density matter completes the triad: creating and controlling, efficiently detecting, and applying the source. This work represented the first use of an ultrafast laser- produced x-ray source as a time-resolving probe in an application relevant to atomic, plasma and high-energy-density matter physics. Using the x-ray source as a backlighter, we adopted a pump-probe geometry to investigate the dynamic changes in electronic structure of a thin metallic film as it is perturbed by an ultrashort laser pulse. Because the laser deposits its energy in a skin depth of about 100 {Angstrom} before expansion occurs, up to gigabar pressure shock waves lasting picosecond in duration have been predicted to form in these novel plasmas. This raises the possibility of studying high- energy-density matter relevant to inertial confinement fusion (ICF) and astrophysics in small-scale laboratory experiments. In the past, time-resolved measurements of K-edge shifts in plasmas driven by nanosecond pulses have been used to infer conditions in highly compressed materials. In this study, we used 100-fs laser pulses to impulsively drive shocks into a sample (an untamped 1000 {Angstrom} aluminum film on 2000 {Angstrom} of parylene-n), measuring L-edge shifts.« less

Local terahertz field enhancement for time-resolved x-ray diffraction

DOE PAGES

Kozina, M.; Pancaldi, M.; Bernhard, C.; ...

2017-02-20

We report local field strength enhancement of single-cycle terahertz (THz) pulses in an ultrafast time-resolved x-ray diffraction experiment. We show that patterning the sample with gold microstructures increases the THz field without changing the THz pulse shape or drastically affecting the quality of the x-ray diffraction pattern. Lastly, we find a five-fold increase in THz-induced x-ray diffraction intensity change in the presence of microstructures on a SrTiO 3 thin-film sample.

Local terahertz field enhancement for time-resolved x-ray diffraction

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

Kozina, M.; Pancaldi, M.; Bernhard, C.

We report local field strength enhancement of single-cycle terahertz (THz) pulses in an ultrafast time-resolved x-ray diffraction experiment. We show that patterning the sample with gold microstructures increases the THz field without changing the THz pulse shape or drastically affecting the quality of the x-ray diffraction pattern. Lastly, we find a five-fold increase in THz-induced x-ray diffraction intensity change in the presence of microstructures on a SrTiO 3 thin-film sample.

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.

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.

Tracking reaction dynamics in solution by pump-probe X-ray absorption spectroscopy and X-ray liquidography (solution scattering).

PubMed

Kim, Jeongho; Kim, Kyung Hwan; Oang, Key Young; Lee, Jae Hyuk; Hong, Kiryong; Cho, Hana; Huse, Nils; Schoenlein, Robert W; Kim, Tae Kyu; Ihee, Hyotcherl

2016-03-07

Characterization of transient molecular structures formed during chemical and biological processes is essential for understanding their mechanisms and functions. Over the last decade, time-resolved X-ray liquidography (TRXL) and time-resolved X-ray absorption spectroscopy (TRXAS) have emerged as powerful techniques for molecular and electronic structural analysis of photoinduced reactions in the solution phase. Both techniques make use of a pump-probe scheme that consists of (1) an optical pump pulse to initiate a photoinduced process and (2) an X-ray probe pulse to monitor changes in the molecular structure as a function of time delay between pump and probe pulses. TRXL is sensitive to changes in the global molecular structure and therefore can be used to elucidate structural changes of reacting solute molecules as well as the collective response of solvent molecules. On the other hand, TRXAS can be used to probe changes in both local geometrical and electronic structures of specific X-ray-absorbing atoms due to the element-specific nature of core-level transitions. These techniques are complementary to each other and a combination of the two methods will enhance the capability of accurately obtaining structural changes induced by photoexcitation. Here we review the principles of TRXL and TRXAS and present recent application examples of the two methods for studying chemical and biological processes in solution. Furthermore, we briefly discuss the prospect of using X-ray free electron lasers for the two techniques, which will allow us to keep track of structural dynamics on femtosecond time scales in various solution-phase molecular reactions.

An analytical model of the effects of pulse pileup on the energy spectrum recorded by energy resolved photon counting x-ray detectors

PubMed Central

Taguchi, Katsuyuki; Frey, Eric C.; Wang, Xiaolan; Iwanczyk, Jan S.; Barber, William C.

2010-01-01

Purpose: Recently, novel CdTe photon counting x-ray detectors (PCXDs) with energy discrimination capabilities have been developed. When such detectors are operated under a high x-ray flux, however, coincident pulses distort the recorded energy spectrum. These distortions are called pulse pileup effects. It is essential to compensate for these effects on the recorded energy spectrum in order to take full advantage of spectral information PCXDs provide. Such compensation can be achieved by incorporating a pileup model into the image reconstruction process for computed tomography, that is, as a part of the forward imaging process, and iteratively estimating either the imaged object or the line integrals using, e.g., a maximum likelihood approach. The aim of this study was to develop a new analytical pulse pileup model for both peak and tail pileup effects for nonparalyzable detectors. Methods: The model takes into account the following factors: The bipolar shape of the pulse, the distribution function of time intervals between random events, and the input probability density function of photon energies. The authors used Monte Carlo simulations to evaluate the model. Results: The recorded spectra estimated by the model were in an excellent agreement with those obtained by Monte Carlo simulations for various levels of pulse pileup effects. The coefficients of variation (i.e., the root mean square difference divided by the mean of measurements) were 5.3%–10.0% for deadtime losses of 1%–50% with a polychromatic incident x-ray spectrum. Conclusions: The proposed pulse pileup model can predict recorded spectrum with relatively good accuracy. PMID:20879558

Towards shot-noise limited diffraction experiments with table-top femtosecond hard x-ray sources.

PubMed

Holtz, Marcel; Hauf, Christoph; Weisshaupt, Jannick; Salvador, Antonio-Andres Hernandez; Woerner, Michael; Elsaesser, Thomas

2017-09-01

Table-top laser-driven hard x-ray sources with kilohertz repetition rates are an attractive alternative to large-scale accelerator-based systems and have found widespread applications in x-ray studies of ultrafast structural dynamics. Hard x-ray pulses of 100 fs duration have been generated at the Cu K α wavelength with a photon flux of up to 10 9 photons per pulse into the full solid angle, perfectly synchronized to the sub-100-fs optical pulses from the driving laser system. Based on spontaneous x-ray emission, such sources display a particular noise behavior which impacts the sensitivity of x-ray diffraction experiments. We present a detailed analysis of the photon statistics and temporal fluctuations of the x-ray flux, together with experimental strategies to optimize the sensitivity of optical pump/x-ray probe experiments. We demonstrate measurements close to the shot-noise limit of the x-ray source.

Towards shot-noise limited diffraction experiments with table-top femtosecond hard x-ray sources

PubMed Central

Holtz, Marcel; Hauf, Christoph; Weisshaupt, Jannick; Salvador, Antonio-Andres Hernandez; Woerner, Michael; Elsaesser, Thomas

2017-01-01

Table-top laser-driven hard x-ray sources with kilohertz repetition rates are an attractive alternative to large-scale accelerator-based systems and have found widespread applications in x-ray studies of ultrafast structural dynamics. Hard x-ray pulses of 100 fs duration have been generated at the Cu Kα wavelength with a photon flux of up to 109 photons per pulse into the full solid angle, perfectly synchronized to the sub-100-fs optical pulses from the driving laser system. Based on spontaneous x-ray emission, such sources display a particular noise behavior which impacts the sensitivity of x-ray diffraction experiments. We present a detailed analysis of the photon statistics and temporal fluctuations of the x-ray flux, together with experimental strategies to optimize the sensitivity of optical pump/x-ray probe experiments. We demonstrate measurements close to the shot-noise limit of the x-ray source. PMID:28795079

The superslow pulsation X-ray pulsars in high mass X-ray binaries

NASA Astrophysics Data System (ADS)

Wang, Wei

2013-03-01

There exists a special class of X-ray pulsars that exhibit very slow pulsation of P spin > 1000 s in the high mass X-ray binaries (HMXBs). We have studied the temporal and spectral properties of these superslow pulsation neutron star binaries in hard X-ray bands with INTEGRAL observations. Long-term monitoring observations find spin period evolution of two sources: spin-down trend for 4U 2206+54 (P spin ~ 5560 s with Ṗ spin ~ 4.9 × 10-7 s s-1) and long-term spin-up trend for 2S 0114+65 (P spin ~ 9600 s with Ṗ spin ~ -1 × 10-6 s s-1) in the last 20 years. A Be X-ray transient, SXP 1062 (P spin ~ 1062 s), also showed a fast spin-down rate of Ṗ spin ~ 3 × 10-6 s s-1 during an outburst. These superslow pulsation neutron stars cannot be produced in the standard X-ray binary evolution model unless the neutron star has a much stronger surface magnetic field (B > 1014 G). The physical origin of the superslow spin period is still unclear. The possible origin and evolution channels of the superslow pulsation X-ray pulsars are discussed. Superslow pulsation X-ray pulsars could be younger X-ray binary systems, still in the fast evolution phase preceding the final equilibrium state. Alternatively, they could be a new class of neutron star system - accreting magnetars.

GREEN BANK TELESCOPE AND SWIFT X-RAY TELESCOPE OBSERVATIONS OF THE GALACTIC CENTER RADIO MAGNETAR SGR J1745–2900

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

Lynch, Ryan S.; Archibald, Robert F.; Kaspi, Victoria M.

We present results from eight months of Green Bank Telescope 8.7 GHz observations and nearly 18 months of Swift X-ray telescope observations of the radio magnetar SGR J1745–2900. We tracked the radio and X-ray flux density, polarization properties, profile evolution, rotation, and single-pulse behavior. We identified two main periods of activity. The first is characterized by approximately 5.5 months of relatively stable evolution in radio flux density, rotation, and profile shape, while in the second these properties varied substantially. Specifically, a third profile component emerged and the radio flux also became more variable. The single pulse properties also changed, mostmore » notably with a larger fraction of pulses with pulse widths ∼5–20 ms in the erratic state. Bright single pulses are well described by a log-normal energy distribution at low energies, but with an excess at high energies. The 2–10 keV flux decayed steadily since the initial X-ray outburst, while the radio flux remained stable to within ∼20% during the stable state. A joint pulsar timing analysis of the radio and X-ray data shows a level of timing noise unprecedented in a radio magnetar, though during the time covered by the radio data alone the timing noise was at a level similar to that observed in other radio magnetars. While SGR J1745–2900 is similar to other radio magnetars in many regards, it differs by having experienced a period of relative stability in the radio that now appears to have ended, while the X-ray properties evolved independently.« less

Modulated method for efficient, narrow-bandwidth, laser Compton X-ray and gamma-ray sources

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

Barty, Christopher P. J.

A method of x-ray and gamma-ray generation via laser Compton scattering uses the interaction of a specially-formatted, highly modulated, long duration, laser pulse with a high-frequency train of high-brightness electron bunches to both create narrow bandwidth x-ray and gamma-ray sources and significantly increase the laser to Compton photon conversion efficiency.

Talbot-Lau x-ray deflectometer electron density diagnostic for laser and pulsed power high energy density plasma experiments (invited)

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

Valdivia, M. P., E-mail: mpvaldivia@pha.jhu.edu; Stutman, D.; Stoeckl, C.

2016-11-15

Talbot-Lau X-ray deflectometry (TXD) has been developed as an electron density diagnostic for High Energy Density (HED) plasmas. The technique can deliver x-ray refraction, attenuation, elemental composition, and scatter information from a single Moiré image. An 8 keV Talbot-Lau interferometer was deployed using laser and x-pinch backlighters. Grating survival and electron density mapping were demonstrated for 25–29 J, 8–30 ps laser pulses using copper foil targets. Moiré pattern formation and grating survival were also observed using a copper x-pinch driven at 400 kA, ∼1 kA/ns. These results demonstrate the potential of TXD as an electron density diagnostic for HED plasmas.

Talbot-Lau x-ray deflectometer electron density diagnostic for laser and pulsed power high energy density plasma experiments (invited).

PubMed

Valdivia, M P; Stutman, D; Stoeckl, C; Mileham, C; Begishev, I A; Theobald, W; Bromage, J; Regan, S P; Klein, S R; Muñoz-Cordovez, G; Vescovi, M; Valenzuela-Villaseca, V; Veloso, F

2016-11-01

Talbot-Lau X-ray deflectometry (TXD) has been developed as an electron density diagnostic for High Energy Density (HED) plasmas. The technique can deliver x-ray refraction, attenuation, elemental composition, and scatter information from a single Moiré image. An 8 keV Talbot-Lau interferometer was deployed using laser and x-pinch backlighters. Grating survival and electron density mapping were demonstrated for 25-29 J, 8-30 ps laser pulses using copper foil targets. Moiré pattern formation and grating survival were also observed using a copper x-pinch driven at 400 kA, ∼1 kA/ns. These results demonstrate the potential of TXD as an electron density diagnostic for HED plasmas.

Compton backscattered collimated x-ray source

DOEpatents

Ruth, R.D.; Huang, Z.

1998-10-20

A high-intensity, inexpensive and collimated x-ray source is disclosed for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications. 4 figs.

Compton backscattered collimated x-ray source

DOEpatents

Ruth, Ronald D.; Huang, Zhirong

1998-01-01

A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

Compton backscattered collmated X-ray source

DOEpatents

Ruth, Ronald D.; Huang, Zhirong

2000-01-01

A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

An eLIMA model for the 67 s X-ray periodicity in CAL 83

NASA Astrophysics Data System (ADS)

Odendaal, A.; Meintjes, P. J.

2017-05-01

Supersoft X-ray sources (SSSs) are characterized by their low effective temperatures and high X-ray luminosities. The soft X-ray emission can be explained by hydrogen nuclear burning on the surface of a white dwarf (WD) accreting at an extremely high rate. A peculiar ˜67 s periodicity (P67) was previously discovered in the XMM-Newton light curves of the SSS CAL 83. P67 was detected in X-ray light curves spanning ˜9 yr, but exhibits variability of several seconds on time-scales as short as a few hours, and its properties are remarkably similar to those of dwarf nova oscillations (DNOs). DNOs are short time-scale modulations (≲1 min) often observed in dwarf novae during outburst. DNOs are explained by the well-established low-inertia magnetic accretor (LIMA) model. In this paper, we show that P67 and its associated period variability can be satisfactorily explained by an application of the LIMA model to the more 'extreme' environment in an SSS (eLIMA), contrary to another recent study attempting to explain P67 and its associated variability in terms of non-radial g-mode oscillations in the extended envelope of the rapidly accreting WD in CAL 83. In the eLIMA model, P67 originates in an equatorial belt in the WD envelope at the boundary with the inner accretion disc, with the belt weakly coupled to the WD core by an ˜105 G magnetic field. New optical light curves obtained with the Sutherland High-speed Optical Camera are also presented, exhibiting quasi-periodic modulations on time-scales of ˜1000 s, compatible with the eLIMA framework.

The high-energy pulsed X-ray spectrum of HER X-1 as observed with OSO-8. Ph.D. Thesis - Catholic Univ. of America

NASA Technical Reports Server (NTRS)

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

1978-01-01

Her X-1 was observed from 1977 August 30 to September 10 using the High-Energy X-Ray Scintillation Spectrometer on board the OSO-8 satellite. The observation, during which the source was monitored continually for nearly an entire ON-state, covered the energy range from 16 to 280 keV. Pulsed flux measurements as a function of binary orbit and binary phase are presented for energies between 16 and 98 keV. The pulsed flux between 16 and 33 keV exhibited a sharp decrease following the fourth binary orbit and was consistent with zero pulsed flux thereafter. The pulsed spectrum was fitted with a power law, a thermal spectrum without features, and a thermal spectrum with a superposed gaussian centered at 55 keV. The latter fit has the smallest value of chi - squared per degree of freedom, and the resulting integrated line intensity is 1.5 superscript + 4.1 subscript - 1.4 x .001 photons s superscript-1 cm superscript-2 for a width of 3.1 superscript + 9.1 subscript -2.6 keV. This result, while of low statistical significance, agrees with the value observed by Trumper (1978) during the same On-state.

X-ray transmission microscope development

NASA Astrophysics Data System (ADS)

Kaukler, William F.; Rosenberger, Franz E.

1995-08-01

This report covers the third 6 month period, from February 28, 1995 to August 31, 1995, under this contract. The main efforts during this period were the construction of the X-ray furnace, evaluation and selection of the CCD technology for the X-ray camera, solidification experiments with Al alloys and Al-zirconia composites in the prototype furnace, evaluation of specimens for the particle pushing flight experiment - PEPSI, measurements of emitted spectra from X-ray source, testing of the high resolution X-ray test targets, and the establishment of criteria for and selection of peripheral equipment. In addition to these tasks, two presentations were prepared in this period; one for the AIAA Microgravity Symposium and another for the Gordon Conference on Gravitational Effects in Pyisico-Chemical Systems.

X-ray transmission microscope development

NASA Technical Reports Server (NTRS)

Kaukler, William F.; Rosenberger, Franz E.

1995-01-01

This report covers the third 6 month period, from February 28, 1995 to August 31, 1995, under this contract. The main efforts during this period were the construction of the X-ray furnace, evaluation and selection of the CCD technology for the X-ray camera, solidification experiments with Al alloys and Al-zirconia composites in the prototype furnace, evaluation of specimens for the particle pushing flight experiment - PEPSI, measurements of emitted spectra from X-ray source, testing of the high resolution X-ray test targets, and the establishment of criteria for and selection of peripheral equipment. In addition to these tasks, two presentations were prepared in this period; one for the AIAA Microgravity Symposium and another for the Gordon Conference on Gravitational Effects in Pyisico-Chemical Systems.

X-band RF gun and linac for medical Compton scattering X-ray source

NASA Astrophysics Data System (ADS)

Dobashi, Katsuhito; Uesaka, Mitsuru; Fukasawa, Atsushi; Sakamoto, Fumito; Ebina, Futaro; Ogino, Haruyuki; Urakawa, Junji; Higo, Toshiyasu; Akemoto, Mitsuo; Hayano, Hitoshi; Nakagawa, Keiichi

2004-12-01

Compton scattering hard X-ray source for 10-80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U.Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard (10-80 keV) X-rays with the intensities of 108-1010 photons/s (at several stages) and the table-top size. Second important aspect is to reduce noise radiation at a beam dump by adopting the deceleration of electrons after the Compton scattering. This realizes one beamline of a 3rd generation SR source at small facilities without heavy shielding. The final goal is that the linac and laser are installed on the moving gantry. We have designed the X-band (11.424 GHz) traveling-wave-type linac for the purpose. Numerical consideration by CAIN code and luminosity calculation are performed to estimate the X-ray yield. X-band thermionic-cathode RF-gun and RDS(Round Detuned Structure)-type X-band accelerating structure are applied to generate 50 MeV electron beam with 20 pC microbunches (104) for 1 microsecond RF macro-pulse. The X-ray yield by the electron beam and Q-switch Nd:YAG laser of 2 J/10 ns is 107 photons/RF-pulse (108 photons/sec at 10 pps). We design to adopt a technique of laser circulation to increase the X-ray yield up to 109 photons/pulse (1010 photons/s). 50 MW X-band klystron and compact modulator have been constructed and now under tuning. The construction of the whole system has started. X-ray generation and medical application will be performed in the early next year.

Chandra observations of Jupiter's X-ray Aurora during Juno upstream and apojove intervals

NASA Astrophysics Data System (ADS)

Dunn, W.; Jackman, C. M.; Kraft, R.; Gladstone, R.; Branduardi-Raymont, G.; Knigge, C.; Altamirano, D.; Elsner, R.; Kammer, J.

2017-12-01

The Chandra space telescope has recently conducted a number of campaigns to observe Jupiter's X-ray aurora. The first set of campaigns took place in summer 2016 while the Juno spacecraft was upstream of the planet sampling the solar wind. The second set of campaigns took place in February, June and August 2017 at times when the Juno spacecraft was at apojove. These campaigns were planned following the Juno orbit correction to capitalise on the opportunity to image the X-ray emission while Juno was orbiting close to the expected position of the magnetopause. Previous work has suggested that the auroral X-ray emissions map close to the magnetopause boundary [e.g. Vogt et al., 2015; Kimura et al., 2016; Dunn et al., 2016] and thus in situ spacecraft coverage in this region combined with remote observation of the X-rays afford the chance to constrain the drivers of these energetic emissions and determine if they originate on open or closed field lines. We aim to examine possible drivers of X-ray emission including reconnection and the Kelvin-Helmholtz instability and to explore the role of the solar wind in controlling the emissions. We report on these upstream and apojove campaigns including intensities and periodicities of auroral X-ray emissions. This new era of jovian X-ray astronomy means we have more data than ever before, long observing windows (up to 72 ks for this Chandra set), and successive observations relatively closely spaced in time. These features combine to allow us to pursue novel methods for examining periodicities in the X-ray emission. Our work will explore significance testing of emerging periodicities, and the search for coherence in X-ray pulsing over weeks and months, seeking to understand the robustness and regularity of previously reported hot spot X-ray emissions. The periods that emerge from our analysis will be compared against those which emerge from radio and UV wavelengths.

Femtosecond X-ray protein nanocrystallography

PubMed Central

Chapman, Henry N.; Fromme, Petra; Barty, Anton; White, Thomas A.; Kirian, Richard A.; Aquila, Andrew; Hunter, Mark S.; Schulz, Joachim; DePonte, Daniel P.; Weierstall, Uwe; Doak, R. Bruce; Maia, Filipe R. N. C.; Martin, Andrew V.; Schlichting, Ilme; Lomb, Lukas; Coppola, Nicola; Shoeman, Robert L.; Epp, Sascha W.; Hartmann, Robert; Rolles, Daniel; Rudenko, Artem; Foucar, Lutz; Kimmel, Nils; Weidenspointner, Georg; Holl, Peter; Liang, Mengning; Barthelmess, Miriam; Caleman, Carl; Boutet, Sébastien; Bogan, Michael J.; Krzywinski, Jacek; Bostedt, Christoph; Bajt, Saša; Gumprecht, Lars; Rudek, Benedikt; Erk, Benjamin; Schmidt, Carlo; Hömke, André; Reich, Christian; Pietschner, Daniel; Strüder, Lothar; Hauser, Günter; Gorke, Hubert; Ullrich, Joachim; Herrmann, Sven; Schaller, Gerhard; Schopper, Florian; Soltau, Heike; Kühnel, Kai-Uwe; Messerschmidt, Marc; Bozek, John D.; Hau-Riege, Stefan P.; Frank, Matthias; Hampton, Christina Y.; Sierra, Raymond G.; Starodub, Dmitri; Williams, Garth J.; Hajdu, Janos; Timneanu, Nicusor; Seibert, M. Marvin; Andreasson, Jakob; Rocker, Andrea; Jönsson, Olof; Svenda, Martin; Stern, Stephan; Nass, Karol; Andritschke, Robert; Schröter, Claus-Dieter; Krasniqi, Faton; Bott, Mario; Schmidt, Kevin E.; Wang, Xiaoyu; Grotjohann, Ingo; Holton, James M.; Barends, Thomas R. M.; Neutze, Richard; Marchesini, Stefano; Fromme, Raimund; Schorb, Sebastian; Rupp, Daniela; Adolph, Marcus; Gorkhover, Tais; Andersson, Inger; Hirsemann, Helmut; Potdevin, Guillaume; Graafsma, Heinz; Nilsson, Björn; Spence, John C. H.

2012-01-01

X-ray crystallography provides the vast majority of macromolecular structures, but the success of the method relies on growing crystals of sufficient size. In conventional measurements, the necessary increase in X-ray dose to record data from crystals that are too small leads to extensive damage before a diffraction signal can be recorded1-3. It is particularly challenging to obtain large, well-diffracting crystals of membrane proteins, for which fewer than 300 unique structures have been determined despite their importance in all living cells. Here we present a method for structure determination where single-crystal X-ray diffraction ‘snapshots’ are collected from a fully hydrated stream of nanocrystals using femtosecond pulses from a hard-X-ray free-electron laser, the Linac Coherent Light Source4. We prove this concept with nanocrystals of photosystem I, one of the largest membrane protein complexes5. More than 3,000,000 diffraction patterns were collected in this study, and a three-dimensional data set was assembled from individual photosystem I nanocrystals (~200 nm to 2 μm in size). We mitigate the problem of radiation damage in crystallography by using pulses briefer than the timescale of most damage processes6. This offers a new approach to structure determination of macromolecules that do not yield crystals of sufficient size for studies using conventional radiation sources or are particularly sensitive to radiation damage. PMID:21293373

Femtosecond X-ray protein nanocrystallography.

PubMed

Chapman, Henry N; Fromme, Petra; Barty, Anton; White, Thomas A; Kirian, Richard A; Aquila, Andrew; Hunter, Mark S; Schulz, Joachim; DePonte, Daniel P; Weierstall, Uwe; Doak, R Bruce; Maia, Filipe R N C; Martin, Andrew V; Schlichting, Ilme; Lomb, Lukas; Coppola, Nicola; Shoeman, Robert L; Epp, Sascha W; Hartmann, Robert; Rolles, Daniel; Rudenko, Artem; Foucar, Lutz; Kimmel, Nils; Weidenspointner, Georg; Holl, Peter; Liang, Mengning; Barthelmess, Miriam; Caleman, Carl; Boutet, Sébastien; Bogan, Michael J; Krzywinski, Jacek; Bostedt, Christoph; Bajt, Saša; Gumprecht, Lars; Rudek, Benedikt; Erk, Benjamin; Schmidt, Carlo; Hömke, André; Reich, Christian; Pietschner, Daniel; Strüder, Lothar; Hauser, Günter; Gorke, Hubert; Ullrich, Joachim; Herrmann, Sven; Schaller, Gerhard; Schopper, Florian; Soltau, Heike; Kühnel, Kai-Uwe; Messerschmidt, Marc; Bozek, John D; Hau-Riege, Stefan P; Frank, Matthias; Hampton, Christina Y; Sierra, Raymond G; Starodub, Dmitri; Williams, Garth J; Hajdu, Janos; Timneanu, Nicusor; Seibert, M Marvin; Andreasson, Jakob; Rocker, Andrea; Jönsson, Olof; Svenda, Martin; Stern, Stephan; Nass, Karol; Andritschke, Robert; Schröter, Claus-Dieter; Krasniqi, Faton; Bott, Mario; Schmidt, Kevin E; Wang, Xiaoyu; Grotjohann, Ingo; Holton, James M; Barends, Thomas R M; Neutze, Richard; Marchesini, Stefano; Fromme, Raimund; Schorb, Sebastian; Rupp, Daniela; Adolph, Marcus; Gorkhover, Tais; Andersson, Inger; Hirsemann, Helmut; Potdevin, Guillaume; Graafsma, Heinz; Nilsson, Björn; Spence, John C H

2011-02-03

X-ray crystallography provides the vast majority of macromolecular structures, but the success of the method relies on growing crystals of sufficient size. In conventional measurements, the necessary increase in X-ray dose to record data from crystals that are too small leads to extensive damage before a diffraction signal can be recorded. It is particularly challenging to obtain large, well-diffracting crystals of membrane proteins, for which fewer than 300 unique structures have been determined despite their importance in all living cells. Here we present a method for structure determination where single-crystal X-ray diffraction 'snapshots' are collected from a fully hydrated stream of nanocrystals using femtosecond pulses from a hard-X-ray free-electron laser, the Linac Coherent Light Source. We prove this concept with nanocrystals of photosystem I, one of the largest membrane protein complexes. More than 3,000,000 diffraction patterns were collected in this study, and a three-dimensional data set was assembled from individual photosystem I nanocrystals (∼200 nm to 2 μm in size). We mitigate the problem of radiation damage in crystallography by using pulses briefer than the timescale of most damage processes. This offers a new approach to structure determination of macromolecules that do not yield crystals of sufficient size for studies using conventional radiation sources or are particularly sensitive to radiation damage.

Pulse pileup statistics for energy discriminating photon counting x-ray detectors

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

Wang, Adam S.; Harrison, Daniel; Lobastov, Vladimir

Purpose: Energy discriminating photon counting x-ray detectors can be subject to a wide range of flux rates if applied in clinical settings. Even when the incident rate is a small fraction of the detector's maximum periodic rate N{sub 0}, pulse pileup leads to count rate losses and spectral distortion. Although the deterministic effects can be corrected, the detrimental effect of pileup on image noise is not well understood and may limit the performance of photon counting systems. Therefore, the authors devise a method to determine the detector count statistics and imaging performance. Methods: The detector count statistics are derived analyticallymore » for an idealized pileup model with delta pulses of a nonparalyzable detector. These statistics are then used to compute the performance (e.g., contrast-to-noise ratio) for both single material and material decomposition contrast detection tasks via the Cramer-Rao lower bound (CRLB) as a function of the detector input count rate. With more realistic unipolar and bipolar pulse pileup models of a nonparalyzable detector, the imaging task performance is determined by Monte Carlo simulations and also approximated by a multinomial method based solely on the mean detected output spectrum. Photon counting performance at different count rates is compared with ideal energy integration, which is unaffected by count rate. Results: The authors found that an ideal photon counting detector with perfect energy resolution outperforms energy integration for our contrast detection tasks, but when the input count rate exceeds 20%N{sub 0}, many of these benefits disappear. The benefit with iodine contrast falls rapidly with increased count rate while water contrast is not as sensitive to count rates. The performance with a delta pulse model is overoptimistic when compared to the more realistic bipolar pulse model. The multinomial approximation predicts imaging performance very close to the prediction from Monte Carlo simulations. The

Generation of Bright, Spatially Coherent Soft X-Ray High Harmonics in a Hollow Waveguide Using Two-Color Synthesized Laser Pulses.

PubMed

Jin, Cheng; Stein, Gregory J; Hong, Kyung-Han; Lin, C D

2015-07-24

We investigate the efficient generation of low-divergence high-order harmonics driven by waveform-optimized laser pulses in a gas-filled hollow waveguide. The drive waveform is obtained by synthesizing two-color laser pulses, optimized such that highest harmonic yields are emitted from each atom. Optimization of the gas pressure and waveguide configuration has enabled us to produce bright and spatially coherent harmonics extending from the extreme ultraviolet to soft x rays. Our study on the interplay among waveguide mode, atomic dispersion, and plasma effect uncovers how dynamic phase matching is accomplished and how an optimized waveform is maintained when optimal waveguide parameters (radius and length) and gas pressure are identified. Our analysis should help laboratory development in the generation of high-flux bright coherent soft x rays as tabletop light sources for applications.

RXTE and BeppoSAX Observations of the Transient X-ray Pulsar XTE J 18591+083

NASA Technical Reports Server (NTRS)

Corbet, R. H. D.; intZand, J. J. M.; Levine, A. M.; Marshall, F. E.

2008-01-01

We present observations of the 9.8 s X-ray pulsar XTE J159+083 made with the All-Sky Monitor (ASM) and Proportional Counter Array (PCA) on board the Rossi X-ray Timing Explorer (RXTE), and the Wide Field Cameras (WFC) on board BeppoSAX. The ASM data cover a 12 year time interval and show that an extended outburst occurred between approximately MJD50, 250, and 50, 460 (1996 June 16 to 1997 January 12). The ASM data excluding this outburst interval suggest a possible 61 day modulation. Eighteen sets of PCA observations were obtained over an approx. one month interval in 1999. The flux variability measured with the PCA appears consistent with the possible period found with the ASM. The PCA measurements of the pulse period showed it to decrease non-monotonically and then to increase significantly. Doppler shifts due to orbital motion rather than accretion torques appear to be better able to explain the pulse period changes. Observations with the WFC during the extended outburst give an error box which is consistent with a previously determined PCA error box but is significantly smaller. The transient nature of XTE J1859+083 and the length of its pulse period are consistent with it being a Be/neutral star binary. The possible 61 day orbital period would be of the expected length for a Be star system with a 9.8 s pulse period.

Quasi-periodic Pulse Amplitude Modulation in the Accreting Millisecond Pulsar IGR J00291+5934

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

Bult, Peter; Doesburgh, Marieke van; Klis, Michiel van der

We introduce a new method for analyzing the aperiodic variability of coherent pulsations in accreting millisecond X-ray pulsars (AMXPs). Our method involves applying a complex frequency correction to the time-domain light curve, allowing for the aperiodic modulation of the pulse amplitude to be robustly extracted in the frequency domain. We discuss the statistical properties of the resulting modulation spectrum and show how it can be correlated with the non-pulsed emission to determine if the periodic and aperiodic variability are coupled processes. Using this method, we study the 598.88 Hz coherent pulsations of the AMXP IGR J00291+5934 as observed with themore » Rossi X-ray Timing Explorer and XMM-Newton . We demonstrate that our method easily confirms the known coupling between the pulsations and a strong 8 mHz quasi-periodic oscillation (QPO) in XMM-Newton observations. Applying our method to the RXTE observations, we further show, for the first time, that the much weaker 20 mHz QPO and its harmonic are also coupled with the pulsations. We discuss the implications of this coupling and indicate how it may be used to extract new information on the underlying accretion process.« less

A Search for Periodicity in the X-Ray Spectrum of Black Hole Candidate A0620-00

DTIC Science & Technology

1991-06-01

They are observed as radio pulsars and as the X-ray emitting components of binary X-ray sources. The limits of stability of neutron stars are not...4 Lo ). The three candidates are CYG X-1, LMC X-3, and A0620. In this section all data such as mass functions, luminosities, distances, periods, etc...1.4. Finally, we discard data for which a/ lo > 1. Such a point is of little statistical significance since its error bars are so large. Figure 2.2d

Satellite Observations of Rapidly Varying Cosmic X-ray Sources. Ph.D. Thesis - Catholic Univ.

NASA Technical Reports Server (NTRS)

Maurer, G. S.

1979-01-01

The X-ray source data obtained with the high energy celestial X-ray detector on the Orbiting Solar Observatory -8 are presented. The results from the 1977 Crab observation show nonstatistical fluctuations in the pulsed emission and in the structure of the integrated pulse profile which cannot be attributed to any known systematic effect. The Hercules observations presented here provide information on three different aspects of the pulsed X-ray emission: the variation of pulsed flux as a function of the time from the beginning of the ON-state, the variation of pulsed flux as a function of binary phase, and the energy spectrum of the pulse emission.

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.

X-ray absorption spectroscopy using a self-seeded soft X-ray free-electron laser

DOE PAGES

Kroll, Thomas; Kern, Jan; Kubin, Markus; ...

2016-09-19

X-ray free electron lasers (XFELs) enable unprecedented new ways to study the electronic structure and dynamics of transition metal systems. L-edge absorption spectroscopy is a powerful technique for such studies and the feasibility of this method at XFELs for solutions and solids has been demonstrated. But, the required x-ray bandwidth is an order of magnitude narrower than that of self-amplified spontaneous emission (SASE), and additional monochromatization is needed. We compare L-edge x-ray absorption spectroscopy (XAS) of a prototypical transition metal system based on monochromatizing the SASE radiation of the linac coherent light source (LCLS) with a new technique based onmore » self-seeding of LCLS. We demonstrate how L-edge XAS can be performed using the self-seeding scheme without the need of an additional beam line monochromator. Lastly, we show how the spectral shape and pulse energy depend on the undulator setup and how this affects the x-ray spectroscopy measurements.« less

X-ray absorption spectroscopy using a self-seeded soft X-ray free-electron laser

PubMed Central

Kroll, Thomas; Kern, Jan; Kubin, Markus; Ratner, Daniel; Gul, Sheraz; Fuller, Franklin D.; Löchel, Heike; Krzywinski, Jacek; Lutman, Alberto; Ding, Yuantao; Dakovski, Georgi L.; Moeller, Stefan; Turner, Joshua J.; Alonso-Mori, Roberto; Nordlund, Dennis L.; Rehanek, Jens; Weniger, Christian; Firsov, Alexander; Brzhezinskaya, Maria; Chatterjee, Ruchira; Lassalle-Kaiser, Benedikt; Sierra, Raymond G.; Laksmono, Hartawan; Hill, Ethan; Borovik, Andrew; Erko, Alexei; Föhlisch, Alexander; Mitzner, Rolf; Yachandra, Vittal K.; Yano, Junko; Wernet, Philippe; Bergmann, Uwe

2016-01-01

X-ray free electron lasers (XFELs) enable unprecedented new ways to study the electronic structure and dynamics of transition metal systems. L-edge absorption spectroscopy is a powerful technique for such studies and the feasibility of this method at XFELs for solutions and solids has been demonstrated. However, the required x-ray bandwidth is an order of magnitude narrower than that of self-amplified spontaneous emission (SASE), and additional monochromatization is needed. Here we compare L-edge x-ray absorption spectroscopy (XAS) of a prototypical transition metal system based on monochromatizing the SASE radiation of the linac coherent light source (LCLS) with a new technique based on self-seeding of LCLS. We demonstrate how L-edge XAS can be performed using the self-seeding scheme without the need of an additional beam line monochromator. We show how the spectral shape and pulse energy depend on the undulator setup and how this affects the x-ray spectroscopy measurements. PMID:27828320

Broad-band characteristics of seven new hard X-ray selected cataclysmic variables

NASA Astrophysics Data System (ADS)

Bernardini, F.; de Martino, D.; Mukai, K.; Russell, D. M.; Falanga, M.; Masetti, N.; Ferrigno, C.; Israel, G.

2017-10-01

We present timing and spectral analysis of a sample of seven hard X-ray selected cataclysmic variable candidates based on simultaneous X-ray and optical observations collected with XMM-Newton, complemented with Swift/BAT and INTEGRAL /IBIS hard X-ray data and ground-based optical photometry. For six sources, X-ray pulsations are detected for the first time in the range of ˜296-6098 s, identifying them as members of the magnetic class. Swift J0927.7-6945, Swift J0958.0-4208, Swift J1701.3-4304, Swift J2113.5+5422 and possibly PBC J0801.2-4625 are intermediate polars (IPs), while Swift J0706.8+0325 is a short (1.7 h) orbital period polar, the 11th hard X-ray-selected identified so far. X-ray orbital modulation is also observed in Swift J0927.7-6945 (5.2 h) and Swift J2113.5+5422 (4.1 h). Swift J1701.3-4304 is discovered as the longest orbital period (12.8 h) deep eclipsing IP. The spectra of the magnetic systems reveal optically thin multitemperature emission between 0.2 and 60 keV. Energy-dependent spin pulses and the orbital modulation in Swift J0927.7-6945 and Swift J2113.5+5422 are due to intervening local high-density absorbing material (NH ˜ 1022 - 23 cm-2). In Swift J0958.0-4208 and Swift J1701.3-4304, a soft X-ray blackbody (kT ˜ 50 and ˜80 eV) is detected, adding them to the growing group of `soft' IPs. White dwarf masses are determined in the range of ˜ 0.58-1.18 M⊙, indicating massive accreting primaries in five of them. Most sources accrete at rates lower than the expected secular value for their orbital period. Formerly proposed as a long-period (9.4 h) nova-like CV, Swift J0746.3-1608 shows peculiar spectrum and light curves suggesting either an atypical low-luminosity CV or a low-mass X-ray binary.

Massively parallel X-ray holography

NASA Astrophysics Data System (ADS)

Marchesini, Stefano; Boutet, Sébastien; Sakdinawat, Anne E.; Bogan, Michael J.; Bajt, Saša; Barty, Anton; Chapman, Henry N.; Frank, Matthias; Hau-Riege, Stefan P.; Szöke, Abraham; Cui, Congwu; Shapiro, David A.; Howells, Malcolm R.; Spence, John C. H.; Shaevitz, Joshua W.; Lee, Joanna Y.; Hajdu, Janos; Seibert, Marvin M.

2008-09-01

Advances in the development of free-electron lasers offer the realistic prospect of nanoscale imaging on the timescale of atomic motions. We identify X-ray Fourier-transform holography as a promising but, so far, inefficient scheme to do this. We show that a uniformly redundant array placed next to the sample, multiplies the efficiency of X-ray Fourier transform holography by more than three orders of magnitude, approaching that of a perfect lens, and provides holographic images with both amplitude- and phase-contrast information. The experiments reported here demonstrate this concept by imaging a nano-fabricated object at a synchrotron source, and a bacterial cell with a soft-X-ray free-electron laser, where illumination by a single 15-fs pulse was successfully used in producing the holographic image. As X-ray lasers move to shorter wavelengths we expect to obtain higher spatial resolution ultrafast movies of transient states of matter.

Using Poisson-regularized inversion of Bremsstrahlung emission to extract full electron energy distribution functions from x-ray pulse-height detector data

DOE PAGES

Swanson, C.; Jandovitz, P.; Cohen, S. A.

2018-02-27

We measured Electron Energy Distribution Functions (EEDFs) from below 200 eV to over 8 keV and spanning five orders-of-magnitude in intensity, produced in a low-power, RF-heated, tandem mirror discharge in the PFRC-II apparatus. The EEDF was obtained from the x-ray energy distribution function (XEDF) using a novel Poisson-regularized spectrum inversion algorithm applied to pulse-height spectra that included both Bremsstrahlung and line emissions. The XEDF was measured using a specially calibrated Amptek Silicon Drift Detector (SDD) pulse-height system with 125 eV FWHM at 5.9 keV. Finally, the algorithm is found to out-perform current leading x-ray inversion algorithms when the error duemore » to counting statistics is high.« less

Using Poisson-regularized inversion of Bremsstrahlung emission to extract full electron energy distribution functions from x-ray pulse-height detector data

NASA Astrophysics Data System (ADS)

Swanson, C.; Jandovitz, P.; Cohen, S. A.

2018-02-01

We measured Electron Energy Distribution Functions (EEDFs) from below 200 eV to over 8 keV and spanning five orders-of-magnitude in intensity, produced in a low-power, RF-heated, tandem mirror discharge in the PFRC-II apparatus. The EEDF was obtained from the x-ray energy distribution function (XEDF) using a novel Poisson-regularized spectrum inversion algorithm applied to pulse-height spectra that included both Bremsstrahlung and line emissions. The XEDF was measured using a specially calibrated Amptek Silicon Drift Detector (SDD) pulse-height system with 125 eV FWHM at 5.9 keV. The algorithm is found to out-perform current leading x-ray inversion algorithms when the error due to counting statistics is high.

Using Poisson-regularized inversion of Bremsstrahlung emission to extract full electron energy distribution functions from x-ray pulse-height detector data

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

Swanson, C.; Jandovitz, P.; Cohen, S. A.

We measured Electron Energy Distribution Functions (EEDFs) from below 200 eV to over 8 keV and spanning five orders-of-magnitude in intensity, produced in a low-power, RF-heated, tandem mirror discharge in the PFRC-II apparatus. The EEDF was obtained from the x-ray energy distribution function (XEDF) using a novel Poisson-regularized spectrum inversion algorithm applied to pulse-height spectra that included both Bremsstrahlung and line emissions. The XEDF was measured using a specially calibrated Amptek Silicon Drift Detector (SDD) pulse-height system with 125 eV FWHM at 5.9 keV. Finally, the algorithm is found to out-perform current leading x-ray inversion algorithms when the error duemore » to counting statistics is high.« less

Intensity-Modulated Advanced X-ray Source (IMAXS) for Homeland Security Applications

NASA Astrophysics Data System (ADS)

Langeveld, Willem G. J.; Johnson, William A.; Owen, Roger D.; Schonberg, Russell G.

2009-03-01

X-ray cargo inspection systems for the detection and verification of threats and contraband require high x-ray energy and high x-ray intensity to penetrate dense cargo. On the other hand, low intensity is desirable to minimize the radiation footprint. A collaboration between HESCO/PTSE Inc., Schonberg Research Corporation and Rapiscan Laboratories, Inc. has been formed in order to design and build an Intensity-Modulated Advanced X-ray Source (IMAXS). Such a source would allow cargo inspection systems to achieve up to two inches greater imaging penetration capability, while retaining the same average radiation footprint as present fixed-intensity sources. Alternatively, the same penetration capability can be obtained as with conventional sources with a reduction of the average radiation footprint by about a factor of three. The key idea is to change the intensity of the source for each x-ray pulse based on the signal strengths in the inspection system detector array during the previous pulse. In this paper we describe methods to accomplish pulse-to-pulse intensity modulation in both S-band (2998 MHz) and X-band (9303 MHz) linac sources, with diode or triode (gridded) electron guns. The feasibility of these methods has been demonstrated. Additionally, we describe a study of a shielding design that would allow a 6 MV X-band source to be used in mobile applications.

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

Nonlocal heat transport and improved target design for x-ray heating studies at x-ray free electron lasers

NASA Astrophysics Data System (ADS)

Hoidn, Oliver; Seidler, Gerald T.

2018-01-01

The extremely high-power densities and short durations of single pulses of x-ray free electron lasers (XFELs) have opened new opportunities in atomic physics, where complex excitation-relaxation chains allow for high ionization states in atomic and molecular systems, and in dense plasma physics, where XFEL heating of solid-density targets can create unique dense states of matter having temperatures on the order of the Fermi energy. We focus here on the latter phenomena, with special emphasis on the problem of optimum target design to achieve high x-ray heating into the warm dense matter (WDM) state. We report fully three-dimensional simulations of the incident x-ray pulse and the resulting multielectron relaxation cascade to model the spatial energy density deposition in multicomponent targets, with particular focus on the effects of nonlocal heat transport due to the motion of high energy photoelectrons and Auger electrons. We find that nanoscale high-Z /low-Z multicomponent targets can give much improved energy density deposition in lower-Z materials, with enhancements reaching a factor of 100. This has three important benefits. First, it greatly enlarges the thermodynamic parameter space in XFEL x-ray heating studies of lower-Z materials. Second, it allows the use of higher probe photon energies, enabling higher-information content x-ray diffraction (XRD) measurements such as in two-color XFEL operations. Third, while this is merely one step toward optimization of x-ray heating target design, the demonstration of the importance of nonlocal heat transport establishes important common ground between XFEL-based x-ray heating studies and more traditional laser plasma methods.

Experimental Validation of Pulse Phase Tracking for X-Ray Pulsar Based

NASA Technical Reports Server (NTRS)

Anderson, Kevin

2012-01-01

Pulsars are a form of variable celestial source that have shown to be usable as aids for autonomous, deep space navigation. Particularly those sources emitting in the X-ray band are ideal for navigation due to smaller detector sizes. In this paper X-ray photons arriving from a pulsar are modeled as a non-homogeneous Poisson process. The method of pulse phase tracking is then investigated as a technique to measure the radial distance traveled by a spacecraft over an observation interval. A maximum-likelihood phase estimator (MLE) is used for the case where the observed frequency signal is constant. For the varying signal frequency case, an algorithm is used in which the observation window is broken up into smaller blocks over which an MLE is used. The outputs of this phase estimation process were then looped through a digital phase-locked loop (DPLL) in order to reduce the errors and produce estimates of the doppler frequency. These phase tracking algorithms were tested both in a computer simulation environment and using the NASA Goddard Space flight Center X-ray Navigation Laboratory Testbed (GXLT). This provided an experimental validation with photons being emitted by a modulated X-ray source and detected by a silicon-drift detector. Models of the Crab pulsar and the pulsar B1821-24 were used in order to generate test scenarios. Three different simulated detector trajectories were used to be tracked by the phase tracking algorithm: a stationary case, one with constant velocity, and one with constant acceleration. All three were performed in one-dimension along the line of sight to the pulsar. The first two had a constant signal frequency and the third had a time varying frequency. All of the constant frequency cases were processed using the MLE, and it was shown that they tracked the initial phase within 0.15% for the simulations and 2.5% in the experiments, based on an average of ten runs. The MLE-DPLL cascade version of the phase tracking algorithm was used in

Orbital Parameters and Spectroscopy of the Transient X-Ray Pulsar 4U 0115+63

NASA Technical Reports Server (NTRS)

Mueller, Sebastian; Obst,Maria; Kreykenbohm, Ingo; Fuerst, Felix; Kuehnel, Matthias; Wilms, Joern; Klochkov, Dmitry; Staubert, Ruediger; Santangelo, Andrea; Pottschmidt, Katja;

Application of a Focused, Pulsed X-Ray Beam to the Investigation of Single-Event Transients in Al 0.3Ga 0.7N/GaN HEMTs

DOE PAGES

Khachatrian, Ani; Roche, Nicolas J. -H.; Buchner, Stephen P.; ...

2016-12-19

A focused, pulsed x-ray beam was used to compare SET characteristics in pristine and proton-irradiated Al 0.3Ga 0.7N/GaN HEMTs. Measured SET amplitudes and trailing-edge decay times were analyzed as was the collected charge, obtained by integrating the SET pulses over time. SETs generated in proton-irradiated HEMTs differed significantly from those in pristine HEMTs with regard to the decay times and collected charge. The decay times have previously been shown to be attributed to charge trapping by defect states that are caused either by imperfect material growth conditions or by protoninduced displacement damage. The longer decay times observed for proton-irradiated HEMTsmore » are attributed to the presence of additional deep traps created when protons lose energy as they collide with the nuclei of constituent atoms. Comparison of electrical parameters measured before and immediately following exposure to the focused x-ray beam showed little change, confirming the absence of significant charge buildup in passivation layers by the x-rays themselves. In conclusion, a major advantage of the pulsed x-ray technique is that the region under the metal gate can be probed for single-event transients from the top side, an approach incompatible with pulsed-laser SEE testing that involves the use of visible light.« less

Creation of X-Ray Transparency of Matter by Stimulated Elastic Forward Scattering.

PubMed

Stöhr, J; Scherz, A

2015-09-04

X-ray absorption by matter has long been described by the famous Beer-Lambert law. Here, we show how this fundamental law needs to be modified for high-intensity coherent x-ray pulses, now available at x-ray free electron lasers, due to the onset of stimulated elastic forward scattering. We present an analytical expression for the modified polarization-dependent Beer-Lambert law for the case of resonant core-to-valence electronic transitions and incident transform limited x-ray pulses. Upon transmission through a solid, the resonant absorption and dichroic contrasts are found to vanish with increasing x-ray intensity, with the stimulation threshold lowered by orders of magnitude through a resonant superradiantlike effect. Our results have broad implications for the study of matter with x-ray lasers.

Creation of X-Ray Transparency of Matter by Stimulated Elastic Forward Scattering

NASA Astrophysics Data System (ADS)

Stöhr, J.; Scherz, A.

2015-09-01

X-ray absorption by matter has long been described by the famous Beer-Lambert law. Here, we show how this fundamental law needs to be modified for high-intensity coherent x-ray pulses, now available at x-ray free electron lasers, due to the onset of stimulated elastic forward scattering. We present an analytical expression for the modified polarization-dependent Beer-Lambert law for the case of resonant core-to-valence electronic transitions and incident transform limited x-ray pulses. Upon transmission through a solid, the resonant absorption and dichroic contrasts are found to vanish with increasing x-ray intensity, with the stimulation threshold lowered by orders of magnitude through a resonant superradiantlike effect. Our results have broad implications for the study of matter with x-ray lasers.

X-Ray Flare Candidates in Short Gamma-Ray Bursts

NASA Technical Reports Server (NTRS)

Margutti, R.; Chincarini, G.; Granot, J.; Guidorzi, C.; Berger, E.; Bernardini, M. G.; Geherls, N.; Soderberg, A. M.; Stamatikos, M.; Zaninoni, E.

2012-01-01

We present the first systematic study of X-ray flare candidates in short gamma-ray bursts (SGRBs) exploiting the large 6-year Swift database with the aim to constrain the physical nature of such fluctuations. We find that flare candidates appear in different types of SGRB host galaxy environments and show no clear correlation with the X-ray afterglow lifetime; flare candidates are detected both in SGRBs with a bright extended emission in the soft gamma-rays and in SGRBs which do not show such component. We furthermore show that SGRB X-ray flare candidates only partially share the set of observational properties of long GRB (LGRB) flares. In particular, the main parameter driving the duration evolution of X-ray variability episodes in both classes is found to be the elapsed time from the explosion, with very limited dependence on the different progenitors, environments, central engine life-times, prompt variability time-scales and energy budgets. On the contrary, SGRB flare candidates significantly differ from LGRB flares in terms of peak luminosity, isotropic energy, flare-to-prompt luminosity ratio and relative variability flux. However, these differences disappear when the central engine time-scales and energy budget are accounted for, suggesting that (i) flare candidates and prompt pulses in SGRBs likely have a common origin; (ii) similar dissipation and/or emission mechanisms are responsible for the prompt and flare emission in long and short GRBs, with SGRBs being less energetic albeit faster evolving versions of the long class. Finally, we show that in strict analogy to the SGRB prompt emission, flares candidates fall off the lag-luminosity relation defined by LGRBs, thus strengthening the SGRB flare-prompt pulse connection.

Improvement of the radiographic method for measurement of effective energy of pulsed X-ray emission from a PF device for different anode's insert materials.

PubMed

Miremad, Seyed Milad; Shirani, Babak

2018-06-01

In this paper, effective energy of pulsed X-Ray emitted from a Mather-type plasma focus device in stored energy of 2.5 kJ with six different anode's insert materials was measured using radiographic method with attenuation filters. Since intensity and energy of X-ray beam were considerably changed with changing the insert material, the method was improved by using different filters simultaneously in all the experiments and selection of the best filter in each experiment according to the appropriate criteria. Effective energy of pulsed X-ray beam was measured 16, 28, 50, 51, 34 and 44 keV when aluminum, copper, zinc, tin, tungsten and lead were used as insert materials, and aluminum, copper, silver, silver, copper and lead were used as filters, respectively. Copyright © 2018 Elsevier Ltd. All rights reserved.

Technological Challenges to X-Ray FELs

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

Nuhn, Heinz-Dieter

1999-09-16

There is strong interest in the development of x-ray free electron lasers (x-ray FELs). The interest is driven by the scientific opportunities provided by intense, coherent x-rays. An x-ray FEL has all the characteristics of a fourth-generation source: brightness several orders of magnitude greater than presently achieved in third-generation sources, full transverse coherence, and sub-picosecond long pulses. The SLAC and DESY laboratories have presented detailed design studies for X-Ray FEL user facilities around the 0.1 nm wavelength-regime (LCLS at SLAC, TESLA X-Ray FEL at DESY). Both laboratories are engaged in proof-of-principle experiments are longer wavelengths (TTF FEL Phase I atmore » 71 nm, VISA at 600-800 nm) with results expected in 1999. The technologies needed to achieve the proposed performances are those of bright electron sources, of acceleration systems capable of preserving the brightness of the source, and of undulators capable of meeting the magnetic and mechanical tolerances that are required for operation in the SASE mode. This paper discusses the technological challenges presented by the X-Ray FEL projects.« less

Inter-satellites x-ray communication system

NASA Astrophysics Data System (ADS)

Mou, Huan; Li, Bao-quan

2017-02-01

An inter-satellite X-ray communication system is presented in this paper. X-ray has a strong penetrating power without almost attenuation for transmission in outer space when the energy of X-ray photons is more than 10KeV and the atmospheric pressure is lower than 10-1 Pa, so it is convincing of x-ray communication in inter-satellite communication and deep space exploration. Additionally, using X-ray photons as information carriers can be used in some communication applications that laser communication and radio frequency (RF) communication are not available, such as ionization blackout area communication. The inter-satellites X-ray communication system, including the grid modulated X-ray source, the high-sensitivity X-ray detector and the transmitting and receiving antenna, is described explicitly. As the X-ray transmitter, a vacuum-sealed miniature modulated X-ray source has been fabricated via the single-step brazing process in a vacuum furnace. Pulse modulation of X-rays, by means of controlling the voltage value of the grid electrode, is realized. Three focusing electrodes, meanwhile, are used to make the electron beam converge and finally 150μm focusing spot diameter is obtained. The X-ray detector based on silicon avalanche photodiodes (APDs) is chosen as the communication receiver on account of its high temporal resolution and non-vacuum operating environment. Furthermore, considering x-ray emission characteristic and communication distance of X-rays, the multilayer nested rotary parabolic optics is picked out as transmitting and receiving antenna. And as a new concept of the space communication, there will be more important scientific significance and application prospects, called "Next-Generation Communications".

Roadmap of ultrafast x-ray atomic and molecular physics

NASA Astrophysics Data System (ADS)

Young, Linda; Ueda, Kiyoshi; Gühr, Markus; Bucksbaum, Philip H.; Simon, Marc; Mukamel, Shaul; Rohringer, Nina; Prince, Kevin C.; Masciovecchio, Claudio; Meyer, Michael; Rudenko, Artem; Rolles, Daniel; Bostedt, Christoph; Fuchs, Matthias; Reis, David A.; Santra, Robin; Kapteyn, Henry; Murnane, Margaret; Ibrahim, Heide; Légaré, François; Vrakking, Marc; Isinger, Marcus; Kroon, David; Gisselbrecht, Mathieu; L'Huillier, Anne; Wörner, Hans Jakob; Leone, Stephen R.

2018-02-01

X-ray free-electron lasers (XFELs) and table-top sources of x-rays based upon high harmonic generation (HHG) have revolutionized the field of ultrafast x-ray atomic and molecular physics, largely due to an explosive growth in capabilities in the past decade. XFELs now provide unprecedented intensity (1020 W cm-2) of x-rays at wavelengths down to ˜1 Ångstrom, and HHG provides unprecedented time resolution (˜50 attoseconds) and a correspondingly large coherent bandwidth at longer wavelengths. For context, timescales can be referenced to the Bohr orbital period in hydrogen atom of 150 attoseconds and the hydrogen-molecule vibrational period of 8 femtoseconds; wavelength scales can be referenced to the chemically significant carbon K-edge at a photon energy of ˜280 eV (44 Ångstroms) and the bond length in methane of ˜1 Ångstrom. With these modern x-ray sources one now has the ability to focus on individual atoms, even when embedded in a complex molecule, and view electronic and nuclear motion on their intrinsic scales (attoseconds and Ångstroms). These sources have enabled coherent diffractive imaging, where one can image non-crystalline objects in three dimensions on ultrafast timescales, potentially with atomic resolution. The unprecedented intensity available with XFELs has opened new fields of multiphoton and nonlinear x-ray physics where behavior of matter under extreme conditions can be explored. The unprecedented time resolution and pulse synchronization provided by HHG sources has kindled fundamental investigations of time delays in photoionization, charge migration in molecules, and dynamics near conical intersections that are foundational to AMO physics and chemistry. This roadmap coincides with the year when three new XFEL facilities, operating at Ångstrom wavelengths, opened for users (European XFEL, Swiss-FEL and PAL-FEL in Korea) almost doubling the present worldwide number of XFELs, and documents the remarkable progress in HHG capabilities since

Roadmap of ultrafast x-ray atomic and molecular physics

DOE PAGES

Young, Linda; Ueda, Kiyoshi; Gühr, Markus; ...

2018-01-09

X-ray free-electron lasers (XFELs) and table-top sources of x-rays based upon high harmonic generation (HHG) have revolutionized the field of ultrafast x-ray atomic and molecular physics, largely due to an explosive growth in capabilities in the past decade. XFELs now provide unprecedented intensity (10 20 W cm -2) of x-rays at wavelengths down to ~1 Ångstrom, and HHG provides unprecedented time resolution (~50 attoseconds) and a correspondingly large coherent bandwidth at longer wavelengths. For context, timescales can be referenced to the Bohr orbital period in hydrogen atom of 150 attoseconds and the hydrogen-molecule vibrational period of 8 femtoseconds; wavelength scalesmore » can be referenced to the chemically significant carbon K-edge at a photon energy of ~280 eV (44 Ångstroms) and the bond length in methane of ~1 Ångstrom. With these modern x-ray sources one now has the ability to focus on individual atoms, even when embedded in a complex molecule, and view electronic and nuclear motion on their intrinsic scales (attoseconds and Ångstroms). These sources have enabled coherent diffractive imaging, where one can image non-crystalline objects in three dimensions on ultrafast timescales, potentially with atomic resolution. The unprecedented intensity available with XFELs has opened new fields of multiphoton and nonlinear x-ray physics where behavior of matter under extreme conditions can be explored. The unprecedented time resolution and pulse synchronization provided by HHG sources has kindled fundamental investigations of time delays in photoionization, charge migration in molecules, and dynamics near conical intersections that are foundational to AMO physics and chemistry. This roadmap coincides with the year when three new XFEL facilities, operating at Ångstrom wavelengths, opened for users (European XFEL, Swiss-FEL and PAL-FEL in Korea) almost doubling the present worldwide number of XFELs, and documents the remarkable progress in HHG capabilities

Roadmap of ultrafast x-ray atomic and molecular physics

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

Young, Linda; Ueda, Kiyoshi; Gühr, Markus

X-ray free-electron lasers (XFELs) and table-top sources of x-rays based upon high harmonic generation (HHG) have revolutionized the field of ultrafast x-ray atomic and molecular physics, largely due to an explosive growth in capabilities in the past decade. XFELs now provide unprecedented intensity (10 20 W cm -2) of x-rays at wavelengths down to ~1 Ångstrom, and HHG provides unprecedented time resolution (~50 attoseconds) and a correspondingly large coherent bandwidth at longer wavelengths. For context, timescales can be referenced to the Bohr orbital period in hydrogen atom of 150 attoseconds and the hydrogen-molecule vibrational period of 8 femtoseconds; wavelength scalesmore » can be referenced to the chemically significant carbon K-edge at a photon energy of ~280 eV (44 Ångstroms) and the bond length in methane of ~1 Ångstrom. With these modern x-ray sources one now has the ability to focus on individual atoms, even when embedded in a complex molecule, and view electronic and nuclear motion on their intrinsic scales (attoseconds and Ångstroms). These sources have enabled coherent diffractive imaging, where one can image non-crystalline objects in three dimensions on ultrafast timescales, potentially with atomic resolution. The unprecedented intensity available with XFELs has opened new fields of multiphoton and nonlinear x-ray physics where behavior of matter under extreme conditions can be explored. The unprecedented time resolution and pulse synchronization provided by HHG sources has kindled fundamental investigations of time delays in photoionization, charge migration in molecules, and dynamics near conical intersections that are foundational to AMO physics and chemistry. This roadmap coincides with the year when three new XFEL facilities, operating at Ångstrom wavelengths, opened for users (European XFEL, Swiss-FEL and PAL-FEL in Korea) almost doubling the present worldwide number of XFELs, and documents the remarkable progress in HHG capabilities

X-Ray Study of Variable Gamma-Ray Pulsar PSR J2021+4026

NASA Astrophysics Data System (ADS)

Wang, H. H.; Takata, J.; Hu, C.-P.; Lin, L. C. C.; Zhao, J.

2018-04-01

PSR J2021+4026 showed a sudden decrease in the gamma-ray emission at the glitch that occurred around 2011 October 16, and a relaxation of the flux to the pre-glitch state at around 2014 December. We report X-ray analysis results of the data observed by XMM-Newton on 2015 December 20 in the post-relaxation state. To examine any change in the X-ray emission, we compare the properties of the pulse profiles and spectra at the low gamma-ray flux state and at the post-relaxation state. The phase-averaged spectra for both states can be well described by a power-law component plus a blackbody component. The former is dominated by unpulsed emission and probably originated from the pulsar wind nebula as reported by Hui et al. The emission property of the blackbody component is consistent with the emission from the polar cap heated by the back-flow bombardment of the high-energy electrons or positrons that were accelerated in the magnetosphere. We found no significant change in the X-ray emission properties between two states. We suggest that the change of the X-ray luminosity is at an order of ∼4%, which is difficult to measure with the current observations. We model the observed X-ray light curve with the heated polar cap emission, and we speculate that the observed large pulsed fraction is owing to asymmetric magnetospheric structure.

Emerging opportunities in structural biology with X-ray free-electron lasers

PubMed Central

Schlichting, Ilme; Miao, Jianwei

2012-01-01

X-ray free-electron lasers (X-FELs) produce X-ray pulses with extremely brilliant peak intensity and ultrashort pulse duration. It has been proposed that radiation damage can be “outrun” by using an ultra intense and short X-FEL pulse that passes a biological sample before the onset of significant radiation damage. The concept of “diffraction-before-destruction” has been demonstrated recently at the Linac Coherent Light Source, the first operational hard X-ray FEL, for protein nanocrystals and giant virus particles. The continuous diffraction patterns from single particles allow solving the classical “phase problem” by the oversampling method with iterative algorithms. If enough data are collected from many identical copies of a (biological) particle, its three-dimensional structure can be reconstructed. We review the current status and future prospects of serial femtosecond crystallography (SFX) and single-particle coherent diffraction imaging (CDI) with X-FELs. PMID:22922042

X-ray analog pixel array detector for single synchrotron bunch time-resolved imaging.

PubMed

Koerner, Lucas J; Gruner, Sol M

2011-03-01

Dynamic X-ray studies can reach temporal resolutions limited by only the X-ray pulse duration if the detector is fast enough to segregate synchrotron pulses. An analog integrating pixel array detector with in-pixel storage and temporal resolution of around 150 ns, sufficient to isolate pulses, is presented. Analog integration minimizes count-rate limitations and in-pixel storage captures successive pulses. Fundamental tests of noise and linearity as well as high-speed laser measurements are shown. The detector resolved individual bunch trains at the Cornell High Energy Synchrotron Source at levels of up to 3.7 × 10(3) X-rays per pixel per train. When applied to turn-by-turn X-ray beam characterization, single-shot intensity measurements were made with a repeatability of 0.4% and horizontal oscillations of the positron cloud were detected.

X-ray analog pixel array detector for single synchrotron bunch time-resolved imaging

PubMed Central

Koerner, Lucas J.; Gruner, Sol M.

2011-01-01

Dynamic X-ray studies can reach temporal resolutions limited by only the X-ray pulse duration if the detector is fast enough to segregate synchrotron pulses. An analog integrating pixel array detector with in-pixel storage and temporal resolution of around 150 ns, sufficient to isolate pulses, is presented. Analog integration minimizes count-rate limitations and in-pixel storage captures successive pulses. Fundamental tests of noise and linearity as well as high-speed laser measurements are shown. The detector resolved individual bunch trains at the Cornell High Energy Synchrotron Source at levels of up to 3.7 × 103 X-rays per pixel per train. When applied to turn-by-turn X-ray beam characterization, single-shot intensity measurements were made with a repeatability of 0.4% and horizontal oscillations of the positron cloud were detected. PMID:21335901

NuSTAR Hard X-Ray Observation of the Gamma-Ray Binary Candidate HESS J1832-093

NASA Astrophysics Data System (ADS)

Mori, Kaya; Gotthelf, E. V.; Hailey, Charles J.; Hord, Ben J.; de Oña Wilhelmi, Emma; Rahoui, Farid; Tomsick, John A.; Zhang, Shuo; Hong, Jaesub; Garvin, Amani M.; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Harrison, Fiona A.; Stern, Daniel; Zhang, William W.

2017-10-01

We present a hard X-ray observation of the TeV gamma-ray binary candidate HESS J1832-093, which is coincident with the supernova remnant G22.7-0.2, using the Nuclear Spectroscopic Telescope Array. Non-thermal X-ray emission from XMMU J183245-0921539, the X-ray source associated with HESS J1832-093, is detected up to ˜30 keV and is well-described by an absorbed power-law model with a best-fit photon index {{Γ }}=1.5+/- 0.1. A re-analysis of archival Chandra and XMM-Newton data finds that the long-term X-ray flux increase of XMMU J183245-0921539 is {50}-20+40 % (90% C.L.), much less than previously reported. A search for a pulsar spin period or binary orbit modulation yields no significant signal to a pulse fraction limit of {f}p< 19 % in the range 4 ms < P< 40 ks. No red noise is detected in the FFT power spectrum to suggest active accretion from a binary system. While further evidence is required, we argue that the X-ray and gamma-ray properties of XMMU J183245-0921539 are most consistent with a non-accreting binary generating synchrotron X-rays from particle acceleration in the shock formed as a result of the pulsar and stellar wind collision. We also report on three nearby hard X-ray sources, one of which may be associated with diffuse emission from a fast-moving supernova fragment interacting with a dense molecular cloud.

X-ray imaging of fibers

NASA Astrophysics Data System (ADS)

Moosman, B.; Song, Y.; Weathers, L.; Wessel, F.

1996-11-01

A pulsed x-ray backlighter was developed to image exploding wires and cryogenic fibers. The x-ray pulse width is between 10-20 ns, with an output of 100-150 mJ, mostly in the Al k-shell (1.486 keV). The backlighter is located 50 cm from the 20-50 micron diameter target (typically, a copper wire). A 15 micron Al filter eliminates UV emission from the backlighter and target. It is placed 3 cm from the target with SB-5 film directly behind it. From the optical density of the film, target absorption and density can be calculated. The spatial resolution of this system is better than 40 microns. The wire is exploded using a 10 kA, 1 microsecond pulser. Analysis with simultaneous Moire imaging will also be presented. Supported by Los Alamos National Laboratories

Pulsed high-energy gamma rays from PSR 1055-52

NASA Technical Reports Server (NTRS)

Fierro, J. M.; Bertsch, D. L.; Brazier, K. T.; Chiang, J.; D'Amico, N.; Fichtel, C. E.; Hartman, R. C.; Hunter, S. D.; Johnston, S.; Kanbach, G.

1993-01-01

The Energetic Gamma Ray Experiment Telescope (EGRET) aboard the Compton Gamma Ray Observatory has detected a high-energy gamma-ray source at a position coincident with that of the radio pulsar PSR 1055-52. Analysis of the EGRET data at the radio pulsar period of 197 ms has revealed pulsed gamma-radiation at energies above 300 MeV, making PSR 1055-52 the fifth detected high-energy gamma-ray pulsar. The pulsed radiation from PSR 1055-52 has a very hard photon spectral index of -1.18 +/- 0.16 and a high efficiency for converting its rotational energy into gamma-rays. No unpulsed emission was observed.

Diverse Long-Term Variability of Five Candidate High-Mass X-Ray Binaries from Swift Burst Alert Telescope Observations

NASA Technical Reports Server (NTRS)

Corbet, Robin H. D.; Coley, Joel B.; Krimm, Hans A.

2017-01-01

We present an investigation of long-term modulation in the X-ray light curves of five little-studied candidate high-mass X-ray binaries using the Swift Burst Alert Telescope (SWIFT-BAT). IGR J14488-5942 and AX J1700.2-4220 show strong modulation at periods of 49.6 and 44 days, respectively, which are interpreted as orbital periods of Be star systems. For IGR J14488-5942, observations with the Swift X-ray Telescope show a hint of pulsations at 33.4 seconds. For AX J1700.2-4220, 54 second-pulsations were previously found with XMM-Newton. Swift J1816.7-1613 exhibits complicated behavior. The strongest peak in the power spectrum is at a period near 150 days, but this conflicts with a determination of a period of 118.5 days by La Parola et al. AX J1820.5-1434 has been proposed to exhibit modulation near 54 days, but the extended BAT observations suggest modulation at slightly longer than double this at approximately 111 days. There appears to be a long-term change in the shape of the modulation near 111 days, which may explain the apparent discrepancy. The X-ray pulsar XTE J1906+090,which was previously proposed to be a Be star system with an orbital period of approximately 30 days from pulse timing, shows peaks in the power spectrum at 81 and 173 days. The origins of these periods are unclear, although theymight be the orbital period and a superorbital period respectively. For all five sources, the long-term variability, together with the combination of orbital and proposed pulse periods, suggests that the sources contain Be starmass donors.

Diverse Long-term Variability of Five Candidate High-mass X-Ray Binaries from Swift Burst Alert Telescope Observations

NASA Astrophysics Data System (ADS)

Corbet, Robin H. D.; Coley, Joel B.; Krimm, Hans A.

2017-09-01

We present an investigation of long-term modulation in the X-ray light curves of five little-studied candidate high-mass X-ray binaries using the Swift Burst Alert Telescope. IGR J14488-5942 and AX J1700.2-4220 show strong modulation at periods of 49.6 and 44 days, respectively, which are interpreted as orbital periods of Be star systems. For IGR J14488-5942, observations with the Swift X-ray Telescope show a hint of pulsations at 33.4 s. For AX J1700.2-4220, 54 s pulsations were previously found with XMM-Newton. Swift J1816.7-1613 exhibits complicated behavior. The strongest peak in the power spectrum is at a period near 150 days, but this conflicts with a determination of a period of 118.5 days by La Parola et al. AX J1820.5-1434 has been proposed to exhibit modulation near 54 days, but the extended BAT observations suggest modulation at slightly longer than double this at approximately 111 days. There appears to be a long-term change in the shape of the modulation near 111 days, which may explain the apparent discrepancy. The X-ray pulsar XTE J1906+090, which was previously proposed to be a Be star system with an orbital period of ˜30 days from pulse timing, shows peaks in the power spectrum at 81 and 173 days. The origins of these periods are unclear, although they might be the orbital period and a superorbital period respectively. For all five sources, the long-term variability, together with the combination of orbital and proposed pulse periods, suggests that the sources contain Be star mass donors.

Diverse Long-Term Variability of Five Candidate High-Mass X-ray Binaries from Swift Burst Alert Telescope Observations

NASA Astrophysics Data System (ADS)

Corbet, Robin; Coley, Joel Barry; Krimm, Hans A.

2017-08-01

We present an investigation of long-term modulation in the X-ray light curves of five little-studied candidate high-mass X-ray binaries using the Swift Burst Alert Telescope. IGR J14488-5942 and AX J1700.2-4220 show strong modulation at periods of 49.6 and 44 days, respectively, which are interpreted as orbital periods of Be star systems. For IGR J14488-5942, observations with Swift X-ray Telescope show a hint of pulsations at 33.4 s. For AX J1700.2-4220, 54 s pulsations were previously found with XMM-Newton. Swift J1816.7-1613 exhibits complicated behavior. The strongest peak in the power spectrum is at a period near 150 days, but this conflicts with a determination of a period of 118.5 days by La Parola et al. (2014). AX J1820.5-1434 has been proposed to exhibit modulation near 54 days, but the extended BAT observations suggest modulation at slightly longer than double this at approximately 111 days. There appears to be a long-term change in the shape of the modulation near 111 days, which may explain the apparent discrepancy. The X-ray pulsar XTE J1906+090, which was previously proposed to be a Be star system with an orbital period of ˜30 days from pulse timing, shows peaks in the power spectrum at 81 and 173 days. The origins of these periods are unclear, although they might be the orbital period and a superorbital period respectively. For all five sources, the long-term variability, together with the combination of orbital and proposed pulse periods, suggests that the sources contain Be star mass donors.