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Sample records for x-ray beam intensity

  1. Compact integrated X-ray intensity and beam position monitor based on rare gas scintillation

    SciTech Connect

    Revesz, Peter; Ruff, Jacob; Dale, Darren; Krawczyk, Thomas

    2013-05-15

    We have created and tested a compact integrated X-ray beam intensity and position monitor using Ar-gas scintillation. The light generated inside the device's cavity is detected by diametrically opposed PIN diodes located above and below the beam. The intensity is derived from the sum of the top and bottom signals, while the beam position is calculated from the difference-over-sum of the two signals. The device was tested at Cornell High Energy Synchrotron Source with both 17 keV and 59 keV x-rays. For intensity monitoring, the Ar-scintillation monitor performance is comparable to standard ion chambers in terms of precision. As an X-ray beam position monitor the new device response is linear with vertical beam position over a 2 mm span with a precision of 2 {mu}m.

  2. Compact integrated X-ray intensity and beam position monitor based on rare gas scintillation

    NASA Astrophysics Data System (ADS)

    Revesz, Peter; Ruff, Jacob; Dale, Darren; Krawczyk, Thomas

    2013-05-01

    We have created and tested a compact integrated X-ray beam intensity and position monitor using Ar-gas scintillation. The light generated inside the device's cavity is detected by diametrically opposed PIN diodes located above and below the beam. The intensity is derived from the sum of the top and bottom signals, while the beam position is calculated from the difference-over-sum of the two signals. The device was tested at Cornell High Energy Synchrotron Source with both 17 keV and 59 keV x-rays. For intensity monitoring, the Ar-scintillation monitor performance is comparable to standard ion chambers in terms of precision. As an X-ray beam position monitor the new device response is linear with vertical beam position over a 2 mm span with a precision of 2 μm.

  3. Study on fundamental processes of laser welded metals observed with intense x-ray beams

    NASA Astrophysics Data System (ADS)

    Muramatsu, T.; Daido, H.; Shobu, T.; Takase, K.; Tsukimori, K.; Kureta, M.; Segawa, M.; Nishimura, A.; Suzuki, Y.; Kawachi, T.

    With use of photon techniques including visible light, soft and hard x-rays, precise fundamental laser welding processes in the repair and maintenance of nuclear plant engineering were reviewed mechanistically. We make discussions centered on the usefulness of an intense soft x-ray beams for evaluations of spatial residual strain distribution and welded metal convection behavior including the surface morphology. Numerical results obtained with a general purpose three-dimensional code SPLICE for the simulation of the welding and solidifying phenomena. Then it is concluded that the x-ray beam would be useful as one of the powerful tools for understanding the mechanisms of various complex phenomena with higher accuracy and higher resolution.

  4. Thin conductive diamond films as beam intensity monitors for soft x-ray beamlines

    SciTech Connect

    Kummer, K.; Fondacaro, A.; Yakhou-Harris, F.; Sessi, V.; Brookes, N. B.; Pobedinskas, P.; Janssens, S. D.; Haenen, K.; Williams, O. A.; Hees, J.

    2013-03-15

    Quantitative analysis of X-ray absorption and dichroism data requires knowledge of the beamline photon flux during the measurements. We show that thin conductive (B-doped) diamond thin films can be an alternative to the widely used gold meshes for monitoring the beam intensity of soft X-ray beamlines in situ. Limited by the carbon extended x-ray absorption fine structure oscillations, the diamond films become applicable beginning from about 600 eV photon energy, where the important transition metal edges and the rare-earth edges are found. The 100 nm and 250 nm thick free-standing diamond films were grown and tested against standard gold meshes in real-life dichroism experiments performed at beamline ID08 of the European Synchrotron Radiation Facility, Grenoble, France. Quantitative agreement was found between the two experimental data sets. The films feature an extremely high transmission of about 90% and, at the same time, yield a sufficiently strong and clean reference signal. Furthermore, the thin films do not affect the shape of the transmitted beam. X-rays passing mesh-type monitors are subject to diffraction effects, which widen the beam and become particularly disturbing for small beamsizes in the micrometer range.

  5. Generation of Intense Attosecond X-Ray Pulses Using Ultraviolet Laser Induced Microbunching in Electron Beams

    SciTech Connect

    Xiang, D.; Huang, Z.; Stupakov, G.; /SLAC

    2011-11-29

    We propose a scheme that combines the echo-enabled harmonic generation technique with the bunch compression and allows one to generate harmonic numbers of a few hundred in a microbunched beam through up-conversion of the frequency of an ultraviolet seed laser. A few-cycle intense laser is used to generate the required energy chirp in the beam for bunch compression and for selection of an attosecond x-ray pulse. Sending this beam through a short undulator results in an intense isolated attosecond x-ray pulse. Using a representative realistic set of parameters, we show that 1 nm x-ray pulse with peak power of a few hundred MW and duration as short as 20 attoseconds (FWHM) can be generated from a 200 nm ultraviolet seed laser. The proposed scheme may enable the study of electronic dynamics with a resolution beyond the atomic unit of time ({approx}24 attoseconds) and may open a new regime of ultrafast sciences.

  6. High Intensity e-beam Diode Development for Flash X-ray Radiography

    NASA Astrophysics Data System (ADS)

    Oliver, Bryan

    2007-11-01

    A variety of electron beam diodes are being used and developed for the purpose of creating high-brightness, flash x-ray radiography sources. In these diodes, high energy (multi MeV), high current (multi kA), small spot (multi mm) electron beams are generated and stopped in high atomic number anode-targets (typically Ta or W). Beam stopping in the target creates copious amounts of bremsstrahlung radiation. In addition, beam heating of the target liberates material, either in the form of low density (10^12-10^14 cm-3) ion emission or higher density (> 10^15 cm-3) plasma. In all cases, beam/target collective effects dominate the diode and beam characteristics, affecting the radiation properties (dose and spot-size). Recent experiments at Sandia National Laboratories have demonstrated diodes capable of producing > 350 rad@m with 1.7mm FWHM x-ray source distributions. A review of our present theoretical understanding of the diode (s) operation and our experimental and simulation methods to investigate them will be presented. Emphasis will be given to e- beam sources used on state-of-the-art Inductive Voltage Adder (IVA) pulsed-power accelerators. In particular, the physics of magnetically pinched diodes (e.g. the rod-pinch [1,2]), gas-cell focusing diodes [3] and the magnetically immersed [4] diode will be discussed. Various proposed methods to optimize the x-ray intensity and the direction of future diode research will be discussed. [1] G. Cooperstein, et al., Phys. Plasmas 8, 4618 (2001).[2] B.V. Oliver et al., Phys. Plasmas 11, 3976 (2004)[3] B.V. Oliver, et al., IEEE Trans. on Plasma Science 33, 704 (2005).[4] M.G. Mazarakis, et al., Appl. Phys. Lett. 70, 832 (1997)

  7. X-ray beam finder

    DOEpatents

    Gilbert, H.W.

    1983-06-16

    An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

  8. Generating Intense Attosecond X-Ray Pulses Using Ultraviolet-Laser-Induced Microbunching in Electron Beams

    SciTech Connect

    Xiang, D.; Huang, Z.; Stupakov, G.; /SLAC

    2009-03-04

    We propose a scheme that combines the echo-enabled harmonic generation technique with the bunch compression and allows to generate harmonic numbers of a few hundred in a microbunched beam through up-conversion of the frequency of an ultraviolet seed laser. Sending this beam through a short undulator results in an isolated sub-100 attoseconds pulse of x-ray radiation. Using a representative realistic set of parameters, we show that 1 nm x-ray pulse with peak power exceeding 100 MW and duration as short as 34 attoseconds (FWHM) can be generated from a 200 nm ultraviolet seed laser.

  9. Ablation rate estimation of inertial fusion reactor candidate material with intense ion beam and X-ray

    NASA Astrophysics Data System (ADS)

    Kasuya, K.; Kasamatsu, A.; Kinoshita, Y.; Kamiya, T.; Saiki, A.; Renk, T. J.; Olson, C. L.

    2003-03-01

    Various candidate materials were collected from many sources. Some of them were irradiated with intense proton beams at Yokohama campus of Tokyo Institute of Technology (TITech), and some others were irradiated with intense nitrogen beams at Albuquerque site of Sandia National Laboratories (SNL). Intense X-rays of SNL were also used to irradiate other materials including the above collected ones. A series of numerical calculations of X-ray ablations was additionally performed at TITech, which results were compared with the experimental ones. Our aims were to supply necessary data for the future design of inertial fusion reactor chambers. One of the key issues in this field was the ablation thickness of the various chamber wall materials with typical inertial fusion reactions. We measured the ablation thickness of various samples, and we also observed the surface conditions of the samples before and after the irradiations with a microscope and an X-ray luminescence composition analyzer.

  10. White beam x-ray waveguide optics

    SciTech Connect

    Jarre, A.; Salditt, T.; Panzner, T.; Pietsch, U.; Pfeiffer, F.

    2004-07-12

    We report a white beam x-ray waveguide (WG) experiment. A resonant beam coupler x-ray waveguide (RBC) is used simultaneously as a broad bandpass (or multibandpass) monochromator and as a beam compressor. We show that, depending on the geometrical properties of the WG, the exiting beam consists of a defined number of wavelengths which can be shifted by changing the angle of incidence of the white x-ray synchrotron beam. The characteristic far-field pattern is recorded as a function of exit angle and energy. This x-ray optical setup may be used to enhance the intensity of coherent x-ray WG beams since the full energetic acceptance of the WG mode is transmitted.

  11. Results of a search for paraphotons with intense X-ray beams at SPring-8

    NASA Astrophysics Data System (ADS)

    Inada, T.; Namba, T.; Asai, S.; Kobayashi, T.; Tanaka, Y.; Tamasaku, K.; Sawada, K.; Ishikawa, T.

    2013-05-01

    A search for paraphotons, or hidden U (1) gauge bosons, is performed using an intense X-ray beamline at SPring-8. "Light Shining through a Wall" technique is used in this search. No excess of events above background is observed. A stringent constraint is obtained on the photon-paraphoton mixing angle, ? < 8.06 10-5 (95% C.L.) for 0.04eV

  12. Quantitative Measurements of X-ray Intensity

    SciTech Connect

    Haugh, M. J., Schneider, M.

    2011-09-01

    This chapter describes the characterization of several X-ray sources and their use in calibrating different types of X-ray cameras at National Security Technologies, LLC (NSTec). The cameras are employed in experimental plasma studies at Lawrence Livermore National Laboratory (LLNL), including the National Ignition Facility (NIF). The sources provide X-rays in the energy range from several hundred eV to 110 keV. The key to this effort is measuring the X-ray beam intensity accurately and traceable to international standards. This is accomplished using photodiodes of several types that are calibrated using radioactive sources and a synchrotron source using methods and materials that are traceable to the U.S. National Institute of Standards and Technology (NIST). The accreditation procedures are described. The chapter begins with an introduction to the fundamental concepts of X-ray physics. The types of X-ray sources that are used for device calibration are described. The next section describes the photodiode types that are used for measuring X-ray intensity: power measuring photodiodes, energy dispersive photodiodes, and cameras comprising photodiodes as pixel elements. Following their description, the methods used to calibrate the primary detectors, the power measuring photodiodes and the energy dispersive photodiodes, as well as the method used to get traceability to international standards are described. The X-ray source beams can then be measured using the primary detectors. The final section then describes the use of the calibrated X-ray beams to calibrate X-ray cameras. Many of the references are web sites that provide databases, explanations of the data and how it was generated, and data calculations for specific cases. Several general reference books related to the major topics are included. Papers expanding some subjects are cited.

  13. Electron intensity modulation for mixed-beam radiation therapy with an x-ray multi-leaf collimator

    NASA Astrophysics Data System (ADS)

    Weinberg, Rebecca

    The current standard treatment for head and neck cancer at our institution uses intensity-modulated x-ray therapy (IMRT), which improves target coverage and sparing of critical structures by delivering complex fluence patterns from a variety of beam directions to conform dose distributions to the shape of the target volume. The standard treatment for breast patients is field-in-field forward-planned IMRT, with initial tangential fields and additional reduced-weight tangents with blocking to minimize hot spots. For these treatment sites, the addition of electrons has the potential of improving target coverage and sparing of critical structures due to rapid dose falloff with depth and reduced exit dose. In this work, the use of mixed-beam therapy (MBT), i.e., combined intensity-modulated electron and x-ray beams using the x-ray multi-leaf collimator (MLC), was explored. The hypothesis of this study was that addition of intensity-modulated electron beams to existing clinical IMRT plans would produce MBT plans that were superior to the original IMRT plans for at least 50% of selected head and neck and 50% of breast cases. Dose calculations for electron beams collimated by the MLC were performed with Monte Carlo methods. An automation system was created to facilitate communication between the dose calculation engine and the treatment planning system. Energy and intensity modulation of the electron beams was accomplished by dividing the electron beams into 2x2-cm2 beamlets, which were then beam-weight optimized along with intensity-modulated x-ray beams. Treatment plans were optimized to obtain equivalent target dose coverage, and then compared with the original treatment plans. MBT treatment plans were evaluated by participating physicians with respect to target coverage, normal structure dose, and overall plan quality in comparison with original clinical plans. The physician evaluations did not support the hypothesis for either site, with MBT selected as superior in 1 out of the 15 head and neck cases (p=1) and 6 out of 18 breast cases (p=0.95). While MBT was not shown to be superior to IMRT, reductions were observed in doses to critical structures distal to the target along the electron beam direction and to non-target tissues, at the expense of target coverage and dose homogeneity.

  14. Time-dependent, x-ray spectral unfolds and brightness temperatures for intense Li + ion beam-driven hohlraums

    NASA Astrophysics Data System (ADS)

    Fehl, D. L.; Chandler, G. A.; Biggs, F.; Dukart, R. J.; Moats, A. R.; Leeper, R. J.

    1997-01-01

    X-ray-producing hohlraums are being studied as indirect drives for inertial confinement fusion targets. In a 1994 target series on the PBFAII accelerator, cylindrical hohlraum targets were heated by an intense Li+ ion beam and viewed by an array of 13 time-resolved, filtered x-ray detectors (XRDs). The unfold operator (UFO) code and its suite of auxiliary functions were used extensively in obtaining time-resolved x-ray spectra and radiation temperatures from this diagnostic. The UFO was also used to obtain fitted response functions from calibration data, to simulate data from blackbody x-ray spectra of interest, to determine the suitability of various unfolding parameters (e.g., energy domain, energy partition, smoothing conditions, and basis functions), to interpolate the XRD signal traces, and to unfold experimental data. The simulation capabilities of the code were useful in understanding an anomalous feature in the unfolded spectra at low photon energies (⩽100 eV). Uncertainties in the differential and energy-integrated unfolded spectra were estimated from uncertainties in the data. The time-history of the radiation temperature agreed well with independent calculations of the wall temperature in the hohlraum.

  15. Study of x-ray emission from an intense relativistic electron beam using nuclear emulsions and thermoluminescent detectors

    SciTech Connect

    Gordeev, E.M.; Grebenshchikov, V.L.; Drygin, V.N.; Kuksov, P.V.; Kushin, V.V.; Lyapidevskii, V.K.; Meshcherin, B.N.; Smirnova, E.A.; Fanchenko, S.D.; Khokhlov, N.B.

    1984-03-01

    It is shown experimentally that nuclear emulsions can be used to determine the x-ray emission spectra of relativistic electron beams with good spatial resolution. X-ray emission spectra were recorded for the first time in different focusing regions of an electron beam produced by the ''Kal'mar-1'' high-current REB generator. The spectra were found to differ: the hardest x-rays were emitted at the center of the focal spot.

  16. 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.

  17. 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.

  18. Area X-ray or UV camera system for high-intensity beams

    DOEpatents

    Chapman, Henry N. (Livermore, CA); Bajt, Sasa (Livermore, CA); Spiller, Eberhard A. (Livermore, CA); Hau-Riege, Stefan (Fremont, CA), Marchesini, Stefano (Oakland, CA)

    2010-03-02

    A system in one embodiment includes a source for directing a beam of radiation at a sample; a multilayer mirror having a face oriented at an angle of less than 90 degrees from an axis of the beam from the source, the mirror reflecting at least a portion of the radiation after the beam encounters a sample; and a pixellated detector for detecting radiation reflected by the mirror. A method in a further embodiment includes directing a beam of radiation at a sample; reflecting at least some of the radiation diffracted by the sample; not reflecting at least a majority of the radiation that is not diffracted by the sample; and detecting at least some of the reflected radiation. A method in yet another embodiment includes directing a beam of radiation at a sample; reflecting at least some of the radiation diffracted by the sample using a multilayer mirror; and detecting at least some of the reflected radiation.

  19. High speed x-ray beam chopper

    DOEpatents

    McPherson, Armon (Oswego, IL); Mills, Dennis M. (Naperville, IL)

    2002-01-01

    A fast, economical, and compact x-ray beam chopper with a small mass and a small moment of inertia whose rotation can be synchronized and phase locked to an electronic signal from an x-ray source and be monitored by a light beam is disclosed. X-ray bursts shorter than 2.5 microseconds have been produced with a jitter time of less than 3 ns.

  20. X-ray intensity interferometer for undulator radiation

    SciTech Connect

    Gluskin, E.; McNulty, I.; Viccaro, P.J. ); Howells, M.R. )

    1991-01-01

    Intensity interferometry is well established with visible light but has never been demonstrated with x-radiation. We propose to measure the transverse coherence of an x-ray beam, for the first time, using the method of Hanbury Brown and Twiss. The x-ray interferometer consists of an array of slits, a grazing incidence reflective beamsplitter, a pair of fast multichannel plate detectors and a broadband, low-noise correlator circuit. The NSLS X1 or X13 soft x-ray undulator will supply the partially coherent x-rays. We are developing this technique to characterize the coherence properties of x-ray beams from high brilliance insertion devices at third-generation synchrotron light facilities such as the Advanced Photon Source and the Advanced Light Source. 17 refs.

  1. X-ray intensity interferometer for undulator radiation

    SciTech Connect

    Gluskin, E.; McNulty, I.; Viccaro, P.J.; Howells, M.R.

    1991-12-31

    Intensity interferometry is well established with visible light but has never been demonstrated with x-radiation. We propose to measure the transverse coherence of an x-ray beam, for the first time, using the method of Hanbury Brown and Twiss. The x-ray interferometer consists of an array of slits, a grazing incidence reflective beamsplitter, a pair of fast multichannel plate detectors and a broadband, low-noise correlator circuit. The NSLS X1 or X13 soft x-ray undulator will supply the partially coherent x-rays. We are developing this technique to characterize the coherence properties of x-ray beams from high brilliance insertion devices at third-generation synchrotron light facilities such as the Advanced Photon Source and the Advanced Light Source. 17 refs.

  2. Relativistic self-focusing of ultra-high intensity X-ray laser beams in warm quantum plasma with upward density profile

    SciTech Connect

    Habibi, M.; Ghamari, F.

    2014-05-15

    The results of a numerical study of high-intensity X-ray laser beam interaction with warm quantum plasma (WQP) are presented. By means of an upward ramp density profile combined with quantum factors specially the Fermi velocity, we have demonstrated significant relativistic self-focusing (RSF) of a Gaussian electromagnetic beam in the WQP where the Fermi temperature term in the dielectric function is important. For this purpose, we have considered the quantum hydrodynamics model that modifies refractive index of inhomogeneous WQPs with the inclusion of quantum correction through the quantum statistical and diffraction effects in the relativistic regime. Also, to better illustration of the physical difference between warm and cold quantum plasmas and their effect on the RSF, we have derived the envelope equation governing the spot size of X-ray laser beam in Q-plasmas. In addition to the upward ramp density profile, we have found that the quantum effects would be caused much higher oscillation and better focusing of X-ray laser beam in the WQP compared to that of cold quantum case. Our computational results reveal the importance of the use of electrons density profile and Fermi speed in enhancing self-focusing of laser beam.

  3. Dependence of relative intensity of L 1 sub-shell X-rays on ion beam energy

    NASA Astrophysics Data System (ADS)

    Chaves, P. C.; Reis, M. A.; Barradas, N. P.; Kav?i?, Matja

    2007-08-01

    In a previous work, it was shown that L shell X-ray yields relative to the L? transition depend on the irradiation ion beam energy and the chemical species being irradiated [M.A. Reis, P.C. Chaves, J.C. Soares, Nucl. Instr. and Meth. B 239 (2005) 413]. Further studies give rise to the possibility that this dependence persists for transitions to the same sub-shell, where the ionization process is expected to play no role [P.C. Chaves, M.A. Reis, in: Milo Budnar, Matja Kav?i? (Eds.), Proceedings (CD) of the Tenth International Conference on Particle Induced X-ray Emission and its Analytical Application, 4-8 June, Portoro - Slovenia, J. Stefan Institute, Ljubljana, 2004, p. 810]. In the present work, very high counting statistics (>4 106 counts in the peak) W-L spectra collected using a Si(Li) detector and Mo-L spectra obtained using the high resolution Johanson type crystal spectrometer from the Josef Stefan Institute were studied. In the case of Mo, an ultra pure Mo metal foil was used to avoid any possible target contamination and spectra were obtained for proton beam energies between 0.4 and 2.0 MeV. In the case of the W spectra, proton beam energies between 1.40 and 2.38 MeV were used. Normalizing to the theoretical yield ratios and plotting results as a function of the reduced velocity allows a single curve to be drawn for both cases. In this communication the results obtained are presented and discussed.

  4. Time-dependent, x-ray spectral unfolds and brightness temperatures for intense Li{sup +} ion beam-driven hohlraums

    SciTech Connect

    Fehl, D.L.; Chandler, G.A.; Biggs, F.; Dukart, R.J.; Moats, A.R.; Leeper, R.J.

    1996-07-01

    X-ray-producing hohlraums are being studied as indirect drives for Inertial Confinement Fusion targets. In a 1994 target series on the PBFAII accelerator, cylindrical hohlraum targets were heated by an intense Li{sup +} ion beam and viewed by an array of 13 time-resolved, filtered x-ray detectors (XRDs). The UFO unfold code and its suite of auxiliary functions were used extensively in obtaining time- resolved x-ray spectra and radiation temperatures from this diagnostic. UFO was also used to obtain fitted response functions from calibration data, to simulate data from blackbody x-ray spectra of interest, to determine the suitability of various unfolding parameters (e.g., energy domain, energy partition, smoothing conditions, and basis functions), to interpolate the XRD signal traces, and to unfold experimental data. The simulation capabilities of the code were useful in understanding an anomalous feature in the unfolded spectra at low photon energies ({le} 100 eV). Uncertainties in the differential and energy-integrated unfolded spectra were estimated from uncertainties in the data. The time-history of the radiation temperature agreed well with independent calculations of the wall temperature in the hohlraum.

  5. Time-dependent, x-ray spectral unfolds and brightness temperatures for intense Li{sup +} ion beam-driven hohlraums

    SciTech Connect

    Fehl, D.L.; Chandler, G.A.; Biggs, F.; Dukart, R.J.; Moats, A.R.; Leeper, R.J.

    1997-01-01

    X-ray-producing hohlraums are being studied as indirect drives for inertial confinement fusion targets. In a 1994 target series on the PBFAII accelerator, cylindrical hohlraum targets were heated by an intense Li{sup +} ion beam and viewed by an array of 13 time-resolved, filtered x-ray detectors (XRDs). The unfold operator (UFO) code and its suite of auxiliary functions were used extensively in obtaining time-resolved x-ray spectra and radiation temperatures from this diagnostic. The UFO was also used to obtain fitted response functions from calibration data, to simulate data from blackbody x-ray spectra of interest, to determine the suitability of various unfolding parameters (e.g., energy domain, energy partition, smoothing conditions, and basis functions), to interpolate the XRD signal traces, and to unfold experimental data. The simulation capabilities of the code were useful in understanding an anomalous feature in the unfolded spectra at low photon energies ({le}100 eV). Uncertainties in the differential and energy-integrated unfolded spectra were estimated from uncertainties in the data. The time{endash}history of the radiation temperature agreed well with independent calculations of the wall temperature in the hohlraum. {copyright} {ital 1997 American Institute of Physics.}

  6. A new beamstop for microfocus X-ray capillary beams.

    PubMed

    Englich, Ulrich; Revesz, Peter; Miller, William

    2011-09-01

    In order to accurately measure the photon flux and to assist in aligning the beam, we have designed a modified beam stop device based on a photo diode integrated with the beam stop. The beam stop contains a small CdWO(4) crystal that completely stops the X-rays and at the same time produces photoluminescence proportional to the X-ray flux. The light is then guided to a photosensitive diode, using a flexible light pipe, to monitor the flux. With this device we achieve the goal of stopping the primary X-ray beam and simultaneously monitoring the X-ray intensity, thus eliminating the need for integrating ion-chambers into the capillary or collimator mount. PMID:21822345

  7. Clusters in intense x-ray pulses

    NASA Astrophysics Data System (ADS)

    Bostedt, Christoph

    2012-06-01

    Free-electron lasers can deliver extremely intense, coherent x-ray flashes with femtosecond pulse length, opening the door for imaging single nanoscale objects in a single shot. All matter irradiated by these intense x-ray pulses, however, will be transformed into a highly-excited non-equilibrium plasma within femtoseconds. During the x-ray pulse complex electron dynamics and the onset of atomic disorder will be induced, leading to a time-varying sample. We have performed first experiments about x-ray laser pulse -- cluster interaction with a combined spectroscopy and imaging approach at both, the FLASH free electron laser in Hamburg (Germany) and the LCLS x-ray free-electron laser in Stanford (California). Atomic clusters are ideal for investigating the light - matter interaction because their size can be tuned from the molecular to the bulk regime, thus allowing to distinguish between intra and inter atomic processes. Imaging experiments with xenon clusters show power-density dependent changes in the scattering patterns. Modeling the scattering data indicates that the optical constants of the clusters change during the femtosecond pulse due to the transient creation of high charge states. The results show that ultra fast scattering is a promising approach to study transient states of matter on a femtosecond time scale. Coincident recording of time-of-flight spectra and scattering patterns allows the deconvolution of focal volume and particle size distribution effects. Single-shot single-particle experiments with keV x-rays reveal that for the highest power densities an highly excited and hot cluster plasma is formed for which recombination is suppressed. Time resolved infrared pump -- x-ray probe experiments have started. Here, the clusters are pumped into a nanoplasma state and their time evolution is probed with femtosecond x-ray scattering. The data show strong variations in the scattering patterns stemming from electronic reconfigurations in the cluster plasma. The results will be compared to theoretical predictions and discussed in light of current developments at free-electron laser sources.

  8. Exotic X-ray Sources from Intermediate Energy Electron Beams

    SciTech Connect

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

    2003-08-26

    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)

  9. Focal construct geometry for high intensity energy dispersive x-ray diffraction based on x-ray capillary optics

    NASA Astrophysics Data System (ADS)

    Li, Fangzuo; Liu, Zhiguo; Sun, Tianxi; Jiang, Bowen; Zhu, Yu

    2016-03-01

    We presented a focal construct geometry (FCG) method for high intensity energy dispersive X-ray diffraction by utilizing a home-made ellipsoidal single-bounce capillary (ESBC) and a polycapillary parallel X-ray lens (PPXRL). The ESBC was employed to focus the X-rays from a conventional laboratory source into a small focal spot and to produce an annular X-ray beam in the far-field. Additionally, diffracted polychromatic X-rays were confocally collected by the PPXRL attached to a stationary energy-resolved detector. Our FCG method based on ESBC and PPXRL had achieved relatively high intensity diffraction peaks and effectively narrowed the diffraction peak width which was helpful in improving the potential d-spacing resolution for material phase analysis.

  10. Intense attosecond radiation from an X-ray FEL - extended version

    SciTech Connect

    Zholents, Alexander A.; Fawley, William M.

    2003-12-01

    We propose the use of a ultra-relativistic electron beam interacting with a few-cycle, intense laser pulse and an intense pulse of the coherent x-rays to produce a multi-MW intensity, x-ray pulses {approx}100 attoseconds in duration. Due to a naturally-occurring frequency chirp, these pulses can be further temporally compressed.

  11. Fundamental study on ultra-high-speed tomography system utilizing intense flash x-ray generators

    NASA Astrophysics Data System (ADS)

    Sato, Eiichi; Enomoto, Toshiyuki; Kawai, Toshiaki; Izumisawa, Mitsuru; Sato, Koetsu; Ogawa, Akira; Sato, Shigehiro; Takayama, Kazuyoshi

    2008-11-01

    A high-speed x-ray tomography system is useful for observing high-speed phenomena. The experimental setup for tomography consists of a tungsten-target x-ray generator, a tungsten collimator, and a computed radiography system. An object was exposed by a 2-mm-thick fun beam from the x-ray generator, and scattering x-rays from the slice plane were detected using an imaging plate through a tungsten collimator with hole diameters of 0.8 mm. Because the exposed dose for tomography was almost equal to those obtained using two intense flash x-ray generators, ultra-high-speed tomography could be performed.

  12. Calibrating X-ray Imaging Devices for Accurate Intensity Measurement

    SciTech Connect

    Haugh, M. J.

    2011-07-28

    The purpose of the project presented is to develop methods to accurately calibrate X-ray imaging devices. The approach was to develop X-ray source systems suitable for this endeavor and to develop methods to calibrate solid state detectors to measure source intensity. NSTec X-ray sources used for the absolute calibration of cameras are described, as well as the method of calibrating the source by calibrating the detectors. The work resulted in calibration measurements for several types of X-ray cameras. X-ray camera calibration measured efficiency and efficiency variation over the CCD. Camera types calibrated include: CCD, CID, back thinned (back illuminated), front illuminated.

  13. 1D X-ray Beam Compressing Monochromators

    SciTech Connect

    Korytar, D.; Dobrocka, E.; Konopka, P.; Zaprazny, Z.; Ferrari, C.; Mikulik, P.; Vagovic, P.; Ac, V.; Erko, A.; Abrosimov, N.

    2010-04-06

    A total beam compression of 5 and 10 corresponding to the asymmetry angles of 9 deg. and 12 deg. is achieved with V-5 and V-10 monochromators, respectively, in standard single crystal pure germanium (220) X-ray beam compressing (V-shaped) monochromators for CuKalpha{sub 1} radiation. A higher 1D compression of X-ray beam is possible using larger angles of asymmetry, however it is achieved at the expense of the total intensity, which is decreased due to the refraction effect. To increase the monochromator intensity, several ways are considered both theoretically and experimentally. Linearly graded germanium rich Ge{sub x}Si{sub (1-x)} single crystal was used to prepare a V-21 single crystal monochromator with 15 deg. asymmetry angles (compression factor of 21). Its temperature gradient version is discussed for CuKalpha{sub 1} radiation. X-ray diffraction measurements on the graded GeSi monochromator showed more than 3-times higher intensity at the output compared with that of a pure Ge monochromator.

  14. 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. PMID:20113111

  15. Standoff detection of hidden objects using backscattered ultra-intense laser-produced x-rays

    SciTech Connect

    Kuwabara, H.; Mori, Y.; Kitagawa, Y.

    2013-08-28

    Ultra-intense laser-produced sub-ps X-ray pulses can detect backscattered signals from objects hidden in aluminium containers. Coincident measurements using primary X-rays enable differentiation among acrylic, copper, and lead blocks inside the container. Backscattering reveals the shapes of the objects, while their material composition can be identified from the modification methods of the energy spectra of backscattered X-ray beams. This achievement is an important step toward more effective homeland security.

  16. High energy transmission annular beam X-ray diffraction.

    PubMed

    Dicken, Anthony; Shevchuk, Alex; Rogers, Keith; Godber, Simon; Evans, Paul

    2015-03-01

    We demonstrate material phase retrieval by linearly translating extended polycrystalline samples along the symmetry axis of an annular beam of high-energy X-rays. A series of pseudo-monochromatic diffraction images are recorded from the dark region encompassed by the beam. We measure Bragg maxima from different annular gauge volumes in the form of bright spots in the X-ray diffraction intensity. We present the experiment data from three materials with different crystallographic structural properties i.e. near ideal, large grain size and preferred orientation. This technique shows great promise for analytical inspection tasks requiring highly penetrating radiation such as security screening, medicine and non-destructive testing. PMID:25836851

  17. Multiwavelength Anomalous Diffraction at High X-Ray Intensity

    NASA Astrophysics Data System (ADS)

    Son, Sang-Kil; Chapman, Henry N.; Santra, Robin

    2011-11-01

    The multiwavelength anomalous diffraction (MAD) method is used to determine phase information in x-ray crystallography by employing anomalous scattering from heavy atoms. X-ray free-electron lasers (FELs) show promise for revealing the structure of single molecules or nanocrystals, but the phase problem remains largely unsolved. Because of the ultrabrightness of x-ray FEL, samples experience severe electronic radiation damage, especially to heavy atoms, which hinders direct implementation of MAD with x-ray FELs. Here, we propose a generalized version of MAD phasing at high x-ray intensity. We demonstrate the existence of a Karle-Hendrickson-type equation in the high-intensity regime and calculate relevant coefficients with detailed electronic damage dynamics of heavy atoms. The present method offers a potential for ab initio structural determination in femtosecond x-ray nanocrystallography.

  18. Detectors based on wide-gap insulating crystals for registration of intensive beams of nuclear, x-ray, and electromagnetic radiation

    NASA Astrophysics Data System (ADS)

    Kasherininov, P. G.; Lodygin, A. N.; Sokolov, V. K.

    2005-02-01

    The paper concerns the development of a new type of semiconductor detectors based on wide-gap insulating crystals, which are not polarized during the registration of intensive nuclear radiation, x-ray or electromagnetic waves. The detectors offered allow simultaneous registration of the shape and intensity and energy (doze) of radiation as well. I.e. they are detectors-dozemeters of radiations, reveals linear lux-ampere characteristics in a wide range of radiation intensities, are highly sensitive and stable under radiation. Detectors could be prepared on the basis of various insulating crystals with a gap width 2 - 6 eV.

  19. Electron beam welder X-rays its own welds

    NASA Technical Reports Server (NTRS)

    Roden, W. A.

    1967-01-01

    Beam of an electron beam welder X rays its own welds, enabling rapid weld quality checks to be made without removing the work from the vacuum chamber. A tungsten target produces X rays when hit by the beam. They are directed at the weld specimen and recorded on polaroid film.

  20. X-ray generation in laser-heated cluster beams

    NASA Astrophysics Data System (ADS)

    Smirnov, M. B.; Becker, W.

    2006-07-01

    Emission of x-rays by large clusters with 108 to 1010 constituents irradiated by an intense laser pulse ( 1016 to 1018Wcm-2 ) is analyzed. A self-consistent model for the cluster evolution during and after the irradiation is developed. The model takes into account absorption of radiation, formation of multicharged ions, and cluster expansion. The model is applied to relate the parameters of the cluster beam and the laser pulse to those of the forming plasma. It predicts that the plasma stays quasineutral and Maxwellian. We find that the expansion of large clusters goes through different stages after the end of the laser pulse and is not appropriately described by the Coulomb expansion model, which underestimates the cluster lifetime. For a more realistic description, the nonuniformity of the plasma must be considered. X-rays are generated in the interaction of the trapped electrons with the cluster ions. Two such radiative processes are considered in detail: dielectronic recombination and excitation of ions by electron impact followed by photon emission. Under the above conditions, the contributions of both processes to x-ray emission are comparable. To evaluate the x-ray spectrum a statistical description of the spectral lines is justified and applied. Knowing the rates that characterize the processes in the plasma, the main processes proceeding in the system can be identified. A simple calculation including several types of transitions is carried out.

  1. Beam synchronous detection techniques for X-Ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Goujon, Grard; Rogalev, Andre; Goulon, Jos; Feite, Serge; Wilhelm, Fabrice

    2013-03-01

    The Photo diode detectors combine a set of properties that make them most appropriate, in particular, for X-ray Magnetic Circular Dichroism (XMCD) experiments. Under standard operating conditions, the detection bandwidth is primarily limited by the transimpedance preamplifier that converts the very low ac photocurrent into a voltage. On the other hand, when the photodiode is reverse biased, its finite shunt resistance will cause an undesirable, temperature dependent DC dark current. The best strategy to get rid of it is to use synchronous detection techniques. A classical implementation is based on the use of a chopper modulating the X-ray beam intensity at rather low frequencies (typically below 1 kHz). Here we report on the recent development of a fast Xray detection which has the capability to fully exploit the frequency structure of the ESRF X-ray beam (355 KHz and its harmonics). The availability of new wide band preamplifiers allowed us to extend the working frequency range up to a few MHz. A beam synchronous data processing was implemented in large FPGAs. Performances of the new detection system implemented at the ESRF beamline ID12 are illustrated with detection of the Fe K-edge XMCD spectra in garnets, using 4 bunches operation mode with modulation frequency of 1.4 MHz.

  2. Thermal deformation of cryogenically cooled silicon crystals under intense X-ray beams: measurement and finite-element predictions ofthesurface shape

    PubMed Central

    Zhang, Lin; Snchez del Ro, Manuel; Monaco, Giulio; Detlefs, Carsten; Roth, Thomas; Chumakov, Aleksandr I.; Glatzel, Pieter

    2013-01-01

    X-ray crystal monochromators exposed to white-beam X-rays in third-generation synchrotron light sources are subject to thermal deformations that must be minimized using an adequate cooling system. A new approach was used to measure the crystal shape profile and slope of several cryogenically cooled (liquid nitrogen) silicon monochromators as a function of beam power in situ and under heat load. The method utilizes multiple angular scans across the Bragg peak (rocking curve) at various vertical positions of a narrow-gap slit downstream from the monochromator. When increasing the beam power, the surface of the liquid-nitrogen-cooled silicon crystal deforms from a concave shape at low heat load to a convex shape at high heat load, passing through an approximately flat shape at intermediate heat load. Finite-element analysis is used to calculate the crystal thermal deformations. The simulated crystal profiles and slopes are in excellent agreement with experiments. The parameters used in simulations, such as material properties, absorbed power distribution on the crystal and cooling boundary conditions, are described in detail as they are fundamental for obtaining accurate results. PMID:23765298

  3. X-ray interferometer with an x-ray beam splitter

    NASA Astrophysics Data System (ADS)

    Kitamoto, S.; Sakata, K.; Murakami, H.; Yoshida, Y.; Seta, H.

    2012-09-01

    We report our examination of a new X-ray interferometer for observation of celestial objects and our recent work for preparation of laboratory experiments. The new X-ray interferometer is consisting of two at mirrors and one at beam splitter which are used as grazing incident optics. The aimed wave length is a O-K band or a C-K band. The beam splitter and the mirrors are fabricated by Mo/Si multilayer. We measured their atness and found that the measured atness is acceptable for the test experiment. A pin hole X-ray source is also preparing for a laboratory experiment in order to demonstrate a X-ray interference. We investigated a possible observation of accretion disks around BHs and nearby stars. With a reasonable size of the base line, we can measure their size and possibly we can obtain an evidence of a black hole shadow.

  4. X-ray polarization spectroscopy from ultra-intense interactions

    NASA Astrophysics Data System (ADS)

    Booth, N.; Clarke, R.; Gallegos, P.; Gizzi, L.; Gregori, G.; Koester, P.; Labate, L.; Levato, T.; Li, B.; Makita, M.; Pasley, J.; Rajeev, P. P.; Riley, D.; Wagenaars, E.; Waugh, J. N.; Woolsey, N. C.

    2010-08-01

    Detailed knowledge of fast electron energy transport following the interaction of ultrashort intense laser pulses is a key subject for fast ignition. This is a problem relevant to many areas of laser-plasma physics with particular importance to fast ignition and X-ray secondary source development, necessary for the development of large-scale facilities such as HiPER and ELI. Operating two orthogonal crystal spectrometers set at Bragg angles close to 45° determines the X-ray s- and p- polarization ratio. From this ratio, it is possible to infer the velocity distribution function of the fast electron beam within the dense plasma. We report on results of polarization measurements at high density for sulphur and nickel buried layer targets in the high intensity range of 1019 - 1021 Wcm-2. We observe at 45° the Ly-α doublet using two sets of orthogonal highly-orientated pyrolytic graphite (HOPG) crystals set in 1st order for sulphur and 3rd order for nickel.

  5. Generation of intense ultrashort x-ray pulses

    SciTech Connect

    Eder, D.C.; London, R.A.; Rosen, M.D.; Strobel, G.L.

    1993-08-01

    Modeling of x-ray emission from targets heated by an ultrashort-pulse high-intensity optical laser is discussed. One application, using the emitted x rays, is pumping inner-shell photo-ionized x-ray lasers. Short wavelength lasing ({lambda} {le} 15 {Angstrom}) requires fast rise-time 1--3 key x rays to ionize inner K-shell electrons. It has been shown that structured targets, consisting of grooves on a solid material or a composite of clusters, have high absorption. We model grooved targets as an ensemble of exploding foils finding that the rise time of x rays is rapid enough for pumping inner-shell x-ray lasers. We show that simple atomic models can overestimate the energy in x-ray emission bands. High-Z materials are found to have the highest conversion efficiency but mid-Z materials can be used to provide a band of emission at a particular energy. We show that the pondermotive inhibition of expansion has only a small effect on the x-ray emission. The emission of a Au plasma is found to be appropriate for pumping inner-shell lasing at 14.6 {Angstrom} in Ne. The required optical laser intensity is of order 10{sup 17} W/cm{sup 2} using a 100 fsec FWHM duration pulse. To produce a laser with a gain-length product of order 10 requires 5--15 J of optical energy.

  6. LCLS mirror switching of x-ray beam

    NASA Astrophysics Data System (ADS)

    Yin, J.; Zhang, D.; Arnold, B.; Nagler, B.; Lee, H.; Galtier, E.; Heimann, P.

    2013-09-01

    The number of proposals for LCLS science has rapidly increased as all six LCLS x-ray instruments have come online. It created rising demand on beam time. Statistics shows that only about 25 % of LCLS proposals can be allocated beam time. One way to increase access is to share the x-ray beam between the different instruments. The purpose of this study is to quickly switch the x-ray beam between the Matter in Extreme Conditions (MEC) Instrument and the Coherent X-ray Imaging (CXI) or X-ray Correlation Spectroscopy (XCS) Instruments, in order that two of the instruments can perform experiments simultaneously. In the most common operational mode, the MEC Instrument uses one x-ray pulse every 10 minutes, limited by the repetition rate of the high power nanosecond laser system. The MEC M3H mirror steers the x-ray beam to the MEC Instrument from the XCS or CXI Instruments. If the M3H mirror could switch the x-ray beam to MEC within a fraction of the 10 minutes waiting time, multiplexing of the x-ray beam would be achieved. The M3H mirror system has two motion stages for translation and rotation. The long path, 230 m, from the mirror to MEC hutch makes the pointing resolution 0f 100 microns and stability requirements challenging. The present study investigates such capabilities by measuring the correlation between the translation speed and the beam pointing reproducibility. We show that mirror translation can multiplex the LCLS x-ray beam.

  7. Resonant Auger Effect at High X-Ray Intensity

    SciTech Connect

    Rohringer, N; Santra, R

    2008-03-27

    The resonant Auger effect of atomic neon exposed to high-intensity x-ray radiation in resonance with the 1s {yields} 3p transition is discussed. High intensity here means that the x-ray peak intensity is sufficient ({approx} 10{sup 18} W/cm{sup 2}) to induce Rabi oscillations between the neon ground state and the 1s{sup -1}3p ({sup 1}P) state within the relaxation lifetime of the inner-shell vacancy. For the numerical analysis presented, an effective two-level model, including a description of the resonant Auger decay process, is employed. Both coherent and chaotic x-ray pulses are treated. The latter are used to simulate radiation from x-ray free-electron lasers based on the principle of self-amplified spontaneous emission. Observing x-ray-driven atomic population dynamics in the time domain is challenging for chaotic pulse ensembles. A more practical option for experiments using x-ray free-electron lasers is to measure the line profiles in the kinetic energy distribution of the resonant Auger electron. This provides information on both atomic population dynamics and x-ray pulse properties.

  8. Multiwavelength anomalous diffraction at high x-ray intensity

    NASA Astrophysics Data System (ADS)

    Santra, Robin

    2013-05-01

    The coherent x-ray scattering pattern of a molecule is connected to the modulus squared of the Fourier transform of the electron density of the molecule. The phase of this Fourier transform is not measured. As a consequence, a reconstruction of the electron density--and thus of the molecular structure--is not immediately possible. In x-ray crystallography at storage-ring-based synchrotron radiation sources, the multiwavelength anomalous diffraction (MAD) method is used to determine phase information by employing anomalous scattering from heavy atoms. X-ray free-electron lasers (FELs) provide the extremely high x-ray intensity required for revealing the structure of single molecules or nanocrystals, but the phase problem remains largely unsolved. A particular challenge is that, at high x-ray intensity, samples experience severe electronic radiation damage, especially to heavy atoms, which hinders direct implementation of MAD with x-ray FELs. In the first part of the talk, I will discuss how MAD phasing can be extended to high x-ray intensity. The proposed technique relies on the existence of a Karle-Hendrickson-type equation in the high-intensity regime and requires the ability to computationally predict the x-ray-induced ionization dynamics of heavy atoms. In the second part of the talk, this ability will be put to the test. I will review x-ray FEL experiments that have been carried out on atomic xenon and will compare the observations to extensive first-principles calculations. At sufficiently high photon energies, there is good agreement between experiment and theory. However, close to inner-shell edges, which play a key role for MAD phasing, specific discrepancies are found. A strategy will be discussed that is expected to allow us to eliminate these discrepancies.

  9. Saturable absorption of intense hard X-rays in iron.

    PubMed

    Yoneda, Hitoki; Inubushi, Yuichi; Yabashi, Makina; Katayama, Tetsuo; Ishikawa, Tetsuya; Ohashi, Haruhiko; Yumoto, Hirokatsu; Yamauchi, Kazuto; Mimura, Hidekazu; Kitamura, Hikaru

    2014-01-01

    In 1913, Maurice de Broglie discovered the presence of X-ray absorption bands of silver and bromine in photographic emulsion. Over the following century, X-ray absorption spectroscopy was established as a standard basis for element analysis, and further applied to advanced investigation of the structures and electronic states of complex materials. Here we show the first observation of an X-ray-induced change of absorption spectra of the iron K-edge for 7.1-keV ultra-brilliant X-ray free-electron laser pulses with an extreme intensity of 10(20)?W?cm(-2). The highly excited state yields a shift of the absorption edge and an increase of transparency by a factor of 10 with an improvement of the phase front of the transmitted X-rays. This finding, the saturable absorption of hard X-rays, opens a promising path for future innovations of X-ray science by enabling novel attosecond active optics, such as lasing and dynamical spatiotemporal control of X-rays. PMID:25270525

  10. Intense x-ray machine for penetrating radiography

    SciTech Connect

    Lucht, R.A.; Eckhouse, S.

    1989-01-01

    Penetrating radiography has been used for many years in the nuclear weapons research programs. In frequently penetrating radiography has been used in conventional weapons research programs. For example the Los Alamos PHERMEX machine was used to view uranium rods penetrating steel for the GAU-8 program, and the Ector machine was used to see low-density regions in forming metal jets. The armor/anti-armor program at Los Alamos has created a need for an intense flash x-ray machine that can be dedicated to conventional weapons research. The Balanced Technology Initiative, through DARPA, has funded the design and construction of such a machine at Los Alamos. It will be an 8- to 10-MeV diode machine capable of delivering a dose of 500 R at 1 m with a spot size of less than 5 mm. The machine used an 87.5-stage low-inductance Marx generator that charges up a 7.4-/Omega/, 32-ns water line. The water line is discharged through a self-breakdown oil switch into a 12.4-/Omega/ water line that rings up the voltage into the high-impendance x-ray diode. A long (233-cm) vacuum drift tube is used to separate the large-diameter oil-insulated diode region from the x-ray source area that may be exposed to high overpressures by the explosive experiments. The electron beam is self-focused at the target area using a low-pressure background gas. 15 refs., 11 figs.

  11. Quantitative cone beam X-ray luminescence tomography/X-ray computed tomography imaging

    NASA Astrophysics Data System (ADS)

    Chen, Dongmei; Zhu, Shouping; Chen, Xueli; Chao, Tiantian; Cao, Xu; Zhao, Fengjun; Huang, Liyu; Liang, Jimin

    2014-11-01

    X-ray luminescence tomography (XLT) is an imaging technology based on X-ray-excitable materials. The main purpose of this paper is to obtain quantitative luminescence concentration using the structural information of the X-ray computed tomography (XCT) in the hybrid cone beam XLT/XCT system. A multi-wavelength luminescence cone beam XLT method with the structural a priori information is presented to relieve the severe ill-posedness problem in the cone beam XLT. The nanophosphors and phantom experiments were undertaken to access the linear relationship of the system response. Then, an in vivo mouse experiment was conducted. The in vivo experimental results show that the recovered concentration error as low as 6.67% with the location error of 0.85 mm can be achieved. The results demonstrate that the proposed method can accurately recover the nanophosphor inclusion and realize the quantitative imaging.

  12. Quantitative cone beam X-ray luminescence tomography/X-ray computed tomography imaging

    SciTech Connect

    Chen, Dongmei; Zhu, Shouping Chen, Xueli; Chao, Tiantian; Cao, Xu; Zhao, Fengjun; Huang, Liyu; Liang, Jimin

    2014-11-10

    X-ray luminescence tomography (XLT) is an imaging technology based on X-ray-excitable materials. The main purpose of this paper is to obtain quantitative luminescence concentration using the structural information of the X-ray computed tomography (XCT) in the hybrid cone beam XLT/XCT system. A multi-wavelength luminescence cone beam XLT method with the structural a priori information is presented to relieve the severe ill-posedness problem in the cone beam XLT. The nanophosphors and phantom experiments were undertaken to access the linear relationship of the system response. Then, an in vivo mouse experiment was conducted. The in vivo experimental results show that the recovered concentration error as low as 6.67% with the location error of 0.85?mm can be achieved. The results demonstrate that the proposed method can accurately recover the nanophosphor inclusion and realize the quantitative imaging.

  13. Solar Intensity X-ray and particle Spectrometer (SIXS)

    NASA Astrophysics Data System (ADS)

    Huovelin, J.; Vainio, R.; Andersson, H.; Valtonen, E.; Alha, L.; Mlkki, A.; Grande, M.; Fraser, G. W.; Kato, M.; Koskinen, H.; Muinonen, K.; Nrnen, J.; Schmidt, W.; Syrjsuo, M.; Anttila, M.; Vihavainen, T.; Kiuru, E.; Roos, M.; Peltonen, J.; Lehti, J.; Talvioja, M.; Portin, P.; Prydderch, M.

    2010-01-01

    The Solar Intensity X-ray and particle Spectrometer (SIXS) on the BepiColombo Mercury Planetary Orbiter (MPO) will investigate the direct solar X-rays, and energetic protons and electrons which pass the Spacecraft on their way to the surface of Mercury. These measurements are vitally important for understanding quantitatively the processes that make Mercury's surface glow in X-rays, since all X-rays from Mercury are due to interactions of the surface with incoming highly energetic photons and space particles. The X-ray emission of Mercury's surface will be analysed to understand its structure and composition. SIXS data will also be utilised for studies of the solar X-ray corona, flares, solar energetic particles, and the magnetosphere of Mercury, and for providing information on solar eruptions to other BepiColombo instruments. SIXS consists of two detector subsystems. The X-ray detector system includes three identical GaAs PIN detectors which measure the solar spectrum at 1-20 keV energy range, and their combined field-of-view covers 1/4 of the whole sky. The particle detector system consists of an assembly including a cubic central CsI(Tl) scintillator detector with five of its six surfaces covered by a thin Si detector, which together perform low-resolution particle spectroscopy with a rough angular resolution over a field-of-view covering 1/4 of the whole sky. The energy range of detected particle spectra is 0.1-3 MeV for electrons and 1-30 MeV for protons. A major task for the SIXS instrument is the measurement of solar X-rays on the dayside of Mercury's surface to enable modeling of X-ray fluorescence and scattering on the planet's surface. Since highly energetic particles are expected to also induce a significant amount of X-ray emission via particle-induced X-ray emission (PIXE) and bremsstrahlung when they are absorbed by the solid surface of the planet Mercury, SIXS performs measurements of fluxes and spectra of protons and electrons. SIXS performs particle measurement at all orbital phases of the MPO as the particle radiation can occur also on the night side of Mercury. The energy ranges, resolutions, and timings of X-ray and particle measurements by SIXS have been adjusted to match with the requirements for interpretation of data from Mercury's surface, to be performed by utilising the data of the Mercury Imaging X-ray Spectrometer (MIXS), which will measure X-ray emission from the surface.

  14. Single-shot beam-position monitor for x-ray free electron laser

    SciTech Connect

    Tono, Kensuke; Yabashi, Makina; Ishikawa, Tetsuya; Feng Yiping; Fritz, David; Hastings, Jerome

    2011-02-15

    We have developed an x-ray beam-position monitor for detecting the radiation properties of an x-ray free electron laser (FEL). It is composed of four PIN photodiodes that detect backscattered x-rays from a semitransparent diamond film placed in the beam path. The signal intensities from the photodiodes are used to compute the beam intensity and position. A proof-of-principle experiment at a synchrotron light source revealed that the error in the beam position is reduced to below 7 {mu}m by using a nanocrystal diamond film prepared by plasma-enhanced chemical vapor deposition. Owing to high dose tolerance and transparency of the diamond film, the monitor is suitable for routine diagnostics of extremely intense x-ray pulses from the FEL.

  15. The low intensity X-ray imaging scope /Lixiscope/

    NASA Technical Reports Server (NTRS)

    Yin, L. I.; Trombka, J. I.; Seltzer, S. M.; Webber, R. L.; Farr, M. R.; Rennie, J.

    1978-01-01

    A fully portable, small-format X-ray imaging system, Lixiscope (low intensity X-ray imaging scope) is described. In the prototype, which has been built to demonstrate the feasibility of the Lixiscope concept, only well-developed and available components have been used. Consideration is given to the principles of operation of the device, some of its performance characteristics as well as possible dental, medical and industrial applications.

  16. Laboratory-based micro-X-ray fluorescence setup using a von Hamos crystal spectrometer and a focused beam X-ray tube.

    PubMed

    Kayser, Y; B?achucki, W; Dousse, J-Cl; Hoszowska, J; Neff, M; Romano, V

    2014-04-01

    The high-resolution von Hamos bent crystal spectrometer of the University of Fribourg was upgraded with a focused X-ray beam source with the aim of performing micro-sized X-ray fluorescence (XRF) measurements in the laboratory. The focused X-ray beam source integrates a collimating optics mounted on a low-power micro-spot X-ray tube and a focusing polycapillary half-lens placed in front of the sample. The performances of the setup were probed in terms of spatial and energy resolution. In particular, the fluorescence intensity and energy resolution of the von Hamos spectrometer equipped with the novel micro-focused X-ray source and a standard high-power water-cooled X-ray tube were compared. The XRF analysis capability of the new setup was assessed by measuring the dopant distribution within the core of Er-doped SiO2 optical fibers. PMID:24784587

  17. Laboratory-based micro-X-ray fluorescence setup using a von Hamos crystal spectrometer and a focused beam X-ray tube

    SciTech Connect

    Kayser, Y.; B?achucki, W.; Dousse, J.-Cl.; Hoszowska, J.; Neff, M.; Romano, V.

    2014-04-15

    The high-resolution von Hamos bent crystal spectrometer of the University of Fribourg was upgraded with a focused X-ray beam source with the aim of performing micro-sized X-ray fluorescence (XRF) measurements in the laboratory. The focused X-ray beam source integrates a collimating optics mounted on a low-power micro-spot X-ray tube and a focusing polycapillary half-lens placed in front of the sample. The performances of the setup were probed in terms of spatial and energy resolution. In particular, the fluorescence intensity and energy resolution of the von Hamos spectrometer equipped with the novel micro-focused X-ray source and a standard high-power water-cooled X-ray tube were compared. The XRF analysis capability of the new setup was assessed by measuring the dopant distribution within the core of Er-doped SiO{sub 2} optical fibers.

  18. Diffraction imaging of crystals with focused x-ray beams

    SciTech Connect

    Kazimirov, A.; Kohn, V. G.; Cai, Z.-H.

    2010-06-01

    We describe an imaging technique based on diffraction of a focused x-ray beam in crystals. A focused beam is formed by a zone plate and Bragg diffracted from a crystalline sample positioned between the zone plate and the focus. The intensity pattern is recorded by a high-resolution charge-coupled-device detector placed in the focus. Diffraction images recorded from perfect Si and GaAs crystals for various reflections demonstrate the broadening of the focused beam due to a finite scattering length. The images from semiconductor epitaxial films and heterostructures show additional peaks originating from the interfaces with their spatial position corresponding to the depth from the surface. Diffraction images from isolated defects in Si crystal demonstrate capabilities to study bulk defects. Theoretical simulations for perfect crystals show excellent agreement with experiments. We demonstrate that the new imaging technique is depth sensitive and combines structural sensitivity of traditional x-ray topography methods with spatial in-plane resolution provided by focusing.

  19. X-ray beam size measurements on the Advanced Test Accelerator

    SciTech Connect

    Struve, K.W.; Chambers, F.W.; Lauer, E.J.; Slaughter, D.R.

    1986-01-01

    The electron beam size has been determined on the Advanced Test Accelerator (ATA) by intercepting the beam with a target and measuring the resulting x-ray intensity as a function of time as the target is moved through the beam. Several types of targets have been used. One is a tantalum rod which extends completely across the drift chamber. Another is a tungsten powder filled carbon crucible. Both of these probes are moved from shot to shot so that the x-ray signal intensity varies with probe position. A third is a larger tantalum disk which is inserted on beam axis to allow determining beam size on a one shot basis. The x-ray signals are detected with an MCP photomultiplier tube located at 90/sup 0/ to the beamline. It is sufficiently shielded to reject background x-rays and neutrons. The signals were digitized, recorded and later unfolded to produce plots of x-ray intensity versus probe position for several times during the pulse. The presumption that the x-ray intensity is proportional to beam current density is checked computationally. Details of the probe construction and PMT shielding, as well as sample measurements are given.

  20. Spherical nanoplasmas irradiated by intense x-ray sources

    NASA Astrophysics Data System (ADS)

    Martins, Joana; Peano, Fabio; Fajardo, Marta; Fonseca, Ricardo; Silva, Luis

    2006-10-01

    Clusters exposed to ultra-short ultra-intense infra-red laser pulses can undergo a Coulomb explosion. Using two sequential pulses it is possible to control the dynamics of the explosion, and to produce multibranch structures in the phase space (shock shells). In x-ray irradiated clusters, the electron excursion length in the radiation field is shorter than the typical cluster dimension, and a pure Coulomb explosion is difficult to achieve. The initial cluster dynamics is mainly determined by the electron distribution function generated by ionization. Using particle-in-cell simulations performed with OSIRIS 2.0 coupled with an x-ray ionization code, we have studied the role of ionization in the expansion dynamics and shock shell formation in clusters irradiated by intense x-ray pulses (e.g. XFEL and LCLS sources). Our results show that under suitable conditions, the dynamics of the cluster expansion can be controlled, and shock shell formation with intense x-ray sources is possible using pulse sequences with different intensities, thus opening the way to phase space control of the expansion of nanoplasmas with x-ray sources.

  1. New X-ray beam position monitors with submicron resolution utilizing imaging of scattered X-rays at CHESS

    NASA Astrophysics Data System (ADS)

    Revesz, Peter; Temnykh, Alexander B.; Pauling, Alan K.

    2011-09-01

    At CHESS' A, F and G wiggler beam lines three new video beam position monitors (VBPMs) have been commissioned. These new VBPMs utilize X-rays scattered from the graphite filter (A and F line) or from a beryllium window (G-line) as the white wiggler beam passes through them. As the X-rays scatter in all directions from the scattering medium, a slit camera creates an image of the beam's footprint on a fluorescent screen. This image is then viewed by a CCD camera and analyzed using a computer program to calculate the intensity centroid, the beam profile and integrated intensity. These data are delivered to the CHESS signal archiving system for storage and display. The new systems employ digital cameras. These cameras are free of the noise inherent to the analog systems with long video signal connections. As a result, the beam position data delivered by the new systems are more reliable and accurate as shown by beam position traces using different beam position monitors on the same beam line.

  2. Characterization of X-ray generator beam profiles.

    SciTech Connect

    Mitchell, Dean J; Harding, Lee T.; Thoreson, Gregory G.; Theisen, Lisa Anne; Parmeter, John Ethan; Thompson, Kyle Richard

    2013-07-01

    T to compute the radiography properties of various materials, the flux profiles of X-ray sources must be characterized. This report describes the characterization of X-ray beam profiles from a Kimtron industrial 450 kVp radiography system with a Comet MXC-45 HP/11 bipolar oil-cooled X-ray tube. The empirical method described here uses a detector response function to derive photon flux profiles based on data collected with a small cadmium telluride detector. The flux profiles are then reduced to a simple parametric form that enables computation of beam profiles for arbitrary accelerator energies.

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

    PubMed

    Davidson, R Andrew; Guo, Ting

    2016-01-01

    In this work, we show a new therapeutic approach using 40-120 keV X rays to deliver a radiation dose at the isocenter located many centimeters below the skin surface several hundred times greater than at the skin and how this dose enhancement can be augmented with nanomaterials to create several thousand-fold total dose enhancement effect. This novel approach employs a needle X-ray beam directed at the isocenter centimeters deep in the body while continuously scanning the beam to cover a large solid angle without overlapping at the skin. A Monte Carlo method was developed to simulate an X-ray dose delivered to the isocenter filled with X-ray absorbing and catalytic nanoparticles in a water phantom. An experimental apparatus consisting of a moving plastic phantom irradiated with a stationary 1 mm needle X-ray beam was built to test the theoretical predictions. X-ray films were used to characterize the dose profiles of the scanning X-ray apparatus. Through this work, it was determined that the X-ray dose delivered to the isocenter in a treatment voxel (t-voxel) underneath a 5 cm deep high-density polyethylene (HDPE) phantom was 295 ± 48 times greater than the surface dose. This measured value was in good agreement with the theoretical predicted value of 339-fold. Adding X-ray-absorbing nanoparticles, catalytic nanoparticles or both into the t-voxel can further augment the dose enhancement. For example, we predicted that adding 1 weight percentage (wp) of gold into water could increase the effective dose delivered to the target by onefold. Dose enhancement using 1 mm X-ray beam could reach about 1,600-fold in the t-voxel when 7.5 wp of 88 nm diameter silica-covered gold nanoparticles were added, which we showed in a previously published study can create a dose enhancement of 5.5 ± 0.46-fold without scanning focusing enhancement. Based on the experimental data from that study, mixing 0.02 wp 2.5 nm diameter small tetrakis hydroxymethyl phosphonium chloride (THPC)-coated gold nanoparticles, which created chemical enhancement, with the 7.5 wp 88 nm diameter silica-covered gold nanoparticles, could further double the dose effect at the isocenter, resulting in a total dose enhancement effect of 3,245 ± 600-fold. These results indicate that the three-dimensional scanning focusing method using a needle beam of X rays can deliver a dose several hundred times greater at a deeply embeded target located well below the skin surface. Total dose effect can be enhanced to several thousand-fold by augmenting the scanning focusing effect with X-ray-absorbing and catalytic nanoparticles in the t-voxel. PMID:26731297

  4. Ultrafast absorption of intense x rays by nitrogen molecules

    SciTech Connect

    Buth, Christian; Liu Jicai; Chen, Mau Hsiung; Cryan, James P.; Fang Li; Hoener, Matthias; Berrah, Nora; Glownia, James M.; Coffee, Ryan N.

    2012-06-07

    We devise a theoretical description for the response of nitrogen molecules (N{sub 2}) to ultrashort and intense x rays from the free electron laser Linac Coherent Light Source (LCLS). We set out from a rate-equation description for the x-ray absorption by a nitrogen atom. The equations are formulated using all one-x-ray-photon absorption cross sections and the Auger and radiative decay widths of multiply-ionized nitrogen atoms. Cross sections are obtained with a one-electron theory and decay widths are determined from ab initio computations using the Dirac-Hartree-Slater (DHS) method. We also calculate all binding and transition energies of nitrogen atoms in all charge states with the DHS method as the difference of two self-consistent field (SCF) calculations ({Delta}SCF method). To describe the interaction with N{sub 2}, a detailed investigation of intense x-ray-induced ionization and molecular fragmentation are carried out. As a figure of merit, we calculate ion yields and the average charge state measured in recent experiments at the LCLS. We use a series of phenomenological models of increasing sophistication to unravel the mechanisms of the interaction of x rays with N{sub 2}: a single atom, a symmetric-sharing model, and a fragmentation-matrix model are developed. The role of the formation and decay of single and double core holes, the metastable states of N{sub 2}{sup 2+}, and molecular fragmentation are explained.

  5. High Intensity X-Ray Coupling to Meteorite Targets

    NASA Astrophysics Data System (ADS)

    Remo, J. L.; Furnish, M. D.; Hammerling, P.

    2001-06-01

    The responses of iron-nickel and stony meteorite samples to high-intensity X-ray pulses (70 - 215 GW/cm^2) pulses generated by exploding wire array hohlraums from the Sandia Z machine are reported. Induced shock waves created particle velocities of 25 - 75 m/s after rarefaction overtake, as measured by VISAR. From these values both momentum and energy coupling coefficients were obtained. These results are compared to recent high-powered-pulsed ( 1 GW/cm2 for 20 ns) 1054 nm laser induced shock pressures and momentum transfer, and energy coupling to iron-rich and stony meteorite targets (J. L. Remo et al, Laser and Particle Beams, 17, 25-44, 1999). These comparisons provide data on the scaling of shock induced effects on inhomogeneous materials in general and meteoritic materials in particular. The combination of both of these experiments extends the regime of high intensity pulsed energy deposition on non-homogeneous materials from the GW/cm^2 to 100's of GW/cm^2, providing valuable empirical insights into the shock critical equations of state and coupling responses. Application to astrophysical and geophysical modeling will be discussed.

  6. Silicon single crystal as back-reflector for high-intensity hard x-rays

    NASA Astrophysics Data System (ADS)

    Pardini, Tom; Boutet, Sbastien; Bradley, Joseph; Doeppner, Tilo; Fletcher, Luke B.; Gardner, Dennis F.; Hill, Randy M.; Hunter, Mark S.; Krzywinski, Jacek; Messerschmidt, Marc; Pak, Arthur E.; Quirin, Florian; Sokolowski-Tinten, Klaus; Williams, Garth J.; Hau-Riege, Stefan P.

    2014-09-01

    At the Lawrence Livermore National Laboratory (LLNL) we have engineered a silicon prototype sample that can be used to reflect focused hard x-ray photons at high intensities in back-scattering geometry.1 Our work is motivated by the need for an all-x-ray pump-and-probe capability at X-ray Free Electron Lasers (XFELs) such as the Linac Coherent Light Source (LCSL) at SLAC. In the first phase of our project, we exposed silicon single crystal to the LCLS beam, and quantitatively studied the x-ray induced damage as a function of x-ray fluence. The damage we observed is extensive at fluences typical of pump-and-probe experiments. The conclusions drawn from our data allowed us to design and manufacture a silicon mirror that can limit the local damage, and reflect the incident beam before its single crystal structure is destroyed. In the second phase of this project we tested this prototype back-reflector at the LCLS. Preliminary results suggest that the new mirror geometry yields reproducible Bragg reflectivity at high x-ray fluences, promising a path forward for silicon single crystals as x-ray back-reflectors.

  7. An x-ray technique for precision laser beam synchronization

    SciTech Connect

    Landen, O.L.; Lerche, R.A.; Hay, R.G.; Hammel, B.A.; Kalantar, D.; Cable, M.D.

    1994-05-02

    A new x-ray technique for recording the relative arrival times of multiple laser beams at a common target with better than {+-} 10 ps accuracy has been implemented at the Nova laser facility. 100 ps, 3{omega} Nova beam are focused to separate locations on a gold ribbon target viewed from the side. The measurement consists of using well characterized re-entrant x-ray streak cameras for 1-dimensional streaked imaging of the > 3 keV x-rays emanating from these isolated laser plasmas. After making the necessary correction for the differential laser, x-ray and electron transit times involved, timing offsets as low as {+-} 7 ps are resolved, and on subsequent shots, corrected for, verified and independently checked. This level of synchronization proved critical in meeting the power balance requirements for indirectly-driven pulse-shaped Nova implosions.

  8. Advances in kilovoltage x-ray beam dosimetry

    NASA Astrophysics Data System (ADS)

    Hill, Robin; Healy, Brendan; Holloway, Lois; Kuncic, Zdenka; Thwaites, David; Baldock, Clive

    2014-03-01

    This topical review provides an up-to-date overview of the theoretical and practical aspects of therapeutic kilovoltage x-ray beam dosimetry. Kilovoltage x-ray beams have the property that the maximum dose occurs very close to the surface and thus, they are predominantly used in the treatment of skin cancers but also have applications for the treatment of other cancers. In addition, kilovoltage x-ray beams are used in intra operative units, within animal irradiators and in on-board imagers on linear accelerators and kilovoltage dosimetry is important in these applications as well. This review covers both reference and relative dosimetry of kilovoltage x-ray beams and provides recommendations for clinical measurements based on the literature to date. In particular, practical aspects for the selection of dosimeter and phantom material are reviewed to provide suitable advice for medical physicists. An overview is also presented of dosimeters other than ionization chambers which can be used for both relative and in vivo dosimetry. Finally, issues related to the treatment planning and the use of Monte Carlo codes for solving radiation transport problems in kilovoltage x-ray beams are presented.

  9. Nanoplasma Formation by High Intensity Hard X-rays.

    PubMed

    Tachibana, T; Jurek, Z; Fukuzawa, H; Motomura, K; Nagaya, K; Wada, S; Johnsson, P; Siano, M; Mondal, S; Ito, Y; Kimura, M; Sakai, T; Matsunami, K; Hayashita, H; Kajikawa, J; Liu, X-J; Robert, E; Miron, C; Feifel, R; Marangos, J P; Tono, K; Inubushi, Y; Yabashi, M; Son, S-K; Ziaja, B; Yao, M; Santra, R; Ueda, K

    2015-01-01

    Using electron spectroscopy, we have investigated nanoplasma formation from noble gas clusters exposed to high-intensity hard-x-ray pulses at ~5 keV. Our experiment was carried out at the SPring-8 Angstrom Compact free electron LAser (SACLA) facility in Japan. Dedicated theoretical simulations were performed with the molecular dynamics tool XMDYN. We found that in this unprecedented wavelength regime nanoplasma formation is a highly indirect process. In the argon clusters investigated, nanoplasma is mainly formed through secondary electron cascading initiated by slow Auger electrons. Energy is distributed within the sample entirely through Auger processes and secondary electron cascading following photoabsorption, as in the hard x-ray regime there is no direct energy transfer from the field to the plasma. This plasma formation mechanism is specific to the hard-x-ray regime and may, thus, also be important for XFEL-based molecular imaging studies. In xenon clusters, photo- and Auger electrons contribute more significantly to the nanoplasma formation. Good agreement between experiment and simulations validates our modelling approach. This has wide-ranging implications for our ability to quantitatively predict the behavior of complex molecular systems irradiated by high-intensity hard x-rays. PMID:26077863

  10. Nanoplasma Formation by High Intensity Hard X-rays

    NASA Astrophysics Data System (ADS)

    Tachibana, T.; Jurek, Z.; Fukuzawa, H.; Motomura, K.; Nagaya, K.; Wada, S.; Johnsson, P.; Siano, M.; Mondal, S.; Ito, Y.; Kimura, M.; Sakai, T.; Matsunami, K.; Hayashita, H.; Kajikawa, J.; Liu, X.-J.; Robert, E.; Miron, C.; Feifel, R.; Marangos, J. P.; Tono, K.; Inubushi, Y.; Yabashi, M.; Son, S.-K.; Ziaja, B.; Yao, M.; Santra, R.; Ueda, K.

    2015-06-01

    Using electron spectroscopy, we have investigated nanoplasma formation from noble gas clusters exposed to high-intensity hard-x-ray pulses at ~5?keV. Our experiment was carried out at the SPring-8 Angstrom Compact free electron LAser (SACLA) facility in Japan. Dedicated theoretical simulations were performed with the molecular dynamics tool XMDYN. We found that in this unprecedented wavelength regime nanoplasma formation is a highly indirect process. In the argon clusters investigated, nanoplasma is mainly formed through secondary electron cascading initiated by slow Auger electrons. Energy is distributed within the sample entirely through Auger processes and secondary electron cascading following photoabsorption, as in the hard x-ray regime there is no direct energy transfer from the field to the plasma. This plasma formation mechanism is specific to the hard-x-ray regime and may, thus, also be important for XFEL-based molecular imaging studies. In xenon clusters, photo- and Auger electrons contribute more significantly to the nanoplasma formation. Good agreement between experiment and simulations validates our modelling approach. This has wide-ranging implications for our ability to quantitatively predict the behavior of complex molecular systems irradiated by high-intensity hard x-rays.

  11. Nanoplasma Formation by High Intensity Hard X-rays

    PubMed Central

    Tachibana, T.; Jurek, Z.; Fukuzawa, H.; Motomura, K.; Nagaya, K.; Wada, S.; Johnsson, P.; Siano, M.; Mondal, S.; Ito, Y.; Kimura, M.; Sakai, T.; Matsunami, K.; Hayashita, H.; Kajikawa, J.; Liu, X.-J.; Robert, E.; Miron, C.; Feifel, R.; Marangos, J. P.; Tono, K.; Inubushi, Y.; Yabashi, M.; Son, S.-K.; Ziaja, B.; Yao, M.; Santra, R.; Ueda, K.

    2015-01-01

    Using electron spectroscopy, we have investigated nanoplasma formation from noble gas clusters exposed to high-intensity hard-x-ray pulses at ~5 keV. Our experiment was carried out at the SPring-8 Angstrom Compact free electron LAser (SACLA) facility in Japan. Dedicated theoretical simulations were performed with the molecular dynamics tool XMDYN. We found that in this unprecedented wavelength regime nanoplasma formation is a highly indirect process. In the argon clusters investigated, nanoplasma is mainly formed through secondary electron cascading initiated by slow Auger electrons. Energy is distributed within the sample entirely through Auger processes and secondary electron cascading following photoabsorption, as in the hard x-ray regime there is no direct energy transfer from the field to the plasma. This plasma formation mechanism is specific to the hard-x-ray regime and may, thus, also be important for XFEL-based molecular imaging studies. In xenon clusters, photo- and Auger electrons contribute more significantly to the nanoplasma formation. Good agreement between experiment and simulations validates our modelling approach. This has wide-ranging implications for our ability to quantitatively predict the behavior of complex molecular systems irradiated by high-intensity hard x-rays. PMID:26077863

  12. Quantitative measurement of hard x-ray spectra for high intensity laser produced plasma

    SciTech Connect

    Zhang, Z.; Nishimura, H.; Namimoto, T.; Fujioka, S.; Arikawa, Y.; Hosoda, H.; Azechi, H.; Nishikino, M.; Kawachi, T.; Sagisaka, A.; Orimo, S.; Ogura, K.; Pirozhkov, A.; Yogo, A.; Kiriyama, H.; Kondo, K.; Okano, Y.; Ohshima, S.

    2012-05-15

    X-ray line spectra ranging from 17 to 77 keV were quantitatively measured with a Laue spectrometer, composed of a cylindrically curved crystal and a detector. Either a visible CCD detector coupled with a CsI phosphor screen or an imaging plate can be chosen, depending on the signal intensities and exposure times. The absolute sensitivity of the spectrometer system was calibrated using pre-characterized laser-produced x-ray sources and radioisotopes. The integrated reflectivity for the crystal is in good agreement with predictions by an open code for x-ray diffraction. The energy transfer efficiency from incident laser beams to hot electrons, as the energy transfer agency for specific x-ray line emissions, is derived as a consequence of this work.

  13. Quantitative measurement of hard x-ray spectra for high intensity laser produced plasma.

    PubMed

    Zhang, Z; Nishimura, H; Namimoto, T; Fujioka, S; Arikawa, Y; Nishikino, M; Kawachi, T; Sagisaka, A; Hosoda, H; Orimo, S; Ogura, K; Pirozhkov, A; Yogo, A; Okano, Y; Kiriyama, H; Kondo, K; Ohshima, S; Azechi, H

    2012-05-01

    X-ray line spectra ranging from 17 to 77 keV were quantitatively measured with a Laue spectrometer, composed of a cylindrically curved crystal and a detector. Either a visible CCD detector coupled with a CsI phosphor screen or an imaging plate can be chosen, depending on the signal intensities and exposure times. The absolute sensitivity of the spectrometer system was calibrated using pre-characterized laser-produced x-ray sources and radioisotopes. The integrated reflectivity for the crystal is in good agreement with predictions by an open code for x-ray diffraction. The energy transfer efficiency from incident laser beams to hot electrons, as the energy transfer agency for specific x-ray line emissions, is derived as a consequence of this work. PMID:22667617

  14. Relative intensity of the K ?5 X-ray line

    NASA Astrophysics Data System (ADS)

    Trk, I.; Papp, T.; Plinks, J.; Budnar, M.; Mhleisen, A.; Kawai, J.; Campbell, J. L.

    1996-06-01

    The relative intensity of the K ?5 (K-M IV,V) X-ray line as a function of the atomic number of the emitting elements is very strongly enhanced around Z = 24 (chromium) relative to predictions of the single-particle model for this electric dipole (E1) forbidden transition. The enhancement is attributed to solid state or chemical effects. The K ?5 transition can be E1-allowed because in chemical compounds the outermost 3d level forms the valence shells, while in metals it becomes a broad band. The intensity of this line can therefore vary with the chemical state. We have determined the {K? 5}/{K? 1} intensity ratio that results from proton impact on Ca, Ti and Cr, and we have collected the experimental data available in the literature. The influence of the sharp increase in the K ?5 intensity on the {K? }/{K? } intensity ratio and on X-ray analytical methods (e.g. proton induced X-ray emission, electron probe microanalysis, etc.) is discussed.

  15. {sup 30}S Beam Development and X-ray Bursts

    SciTech Connect

    Kahl, D.; Kubono, S.; Binh, D. N.; Hashimoto, T.; Hayakawa, S.; Kurihara, Y.; Ohshiro, Y.; Yamaguchi, H.; Chen, A. A.; Chen, J.; Setoodeh nia, K.; Kaji, D.; Nishimura, S.; Kim, A.; Lee, N. H.; Wakabayashi, Y.

    2010-03-01

    Over the past three years, we have worked on developing a well-characterized {sup 30}S radioactive beam to be used in a future experiment aiming to directly measure to extrapolate the {sup 30}S(alpha,p) stellar reaction rate within the Gamow window of Type I X-ray bursts. The importance of the {sup 30}S(alpha,p) reaction to X-ray bursts is discussed. Given the astrophysical motivation, the successful results of and challenges involved in the production of a low-energy {sup 30}S beam are detailed. Finally, an overview of our future plans regarding this on-going project are presented.

  16. L X-ray intensity ratios for high Z elements induced with X-ray tube

    NASA Astrophysics Data System (ADS)

    Wang, Xing; Xu, Zhongfeng; Zhang, Limin

    2015-07-01

    We have studied the intensity ratios I(Lα1,2)/I(Lβ1,2), I(Lα1,2)/I(Lγ) and I(Lβ1,2)/I(Lγ) for elements Ta, W, Au and Pb by 13.1 keV bremsstrahlung radiation. In this work, experimental values were compared with the theoretical results and other experimental results. Theoretical results of the intensity ratios were calculated with theoretical subshell photoionization cross sections, fractional X-ray emission rates, fluorescence yields, and Coster-Kronig transition probabilities. Good agreement can be observed between experimental values and theoretical results. Comparing with L1 and L2 subshells, the ionization cross section of L3 subshell shows a large increase for Ta and W with the variation of excitation energy from 59.5 keV to 13.1 keV.

  17. Relationship between x-ray illumination field size and flat field intensity and its impacts on x-ray imaging

    SciTech Connect

    Dong Xue; Niu Tianye; Jia Xun; Zhu Lei

    2012-10-15

    Purpose: X-ray cone-beam CT (CBCT) is being increasingly used for various clinical applications, while its performance is still hindered by image artifacts. This work investigates a new source of reconstruction error, which is often overlooked in the current CBCT imaging. The authors find that the x-ray flat field intensity (I{sub 0}) varies significantly as the illumination volume size changes at different collimator settings. A wrong I{sub 0} value leads to inaccurate CT numbers of reconstructed images as well as wrong scatter measurements in the CBCT research. Methods: The authors argue that the finite size of x-ray focal spot together with the detector glare effect cause the I{sub 0} variation at different illumination sizes. Although the focal spot of commercial x-ray tubes typically has a nominal size of less than 1 mm, the off-focal-spot radiation covers an area of several millimeters on the tungsten target. Due to the large magnification factor from the field collimator to the detector, the penumbra effects of the collimator blades result in different I{sub 0} values for different illumination field sizes. Detector glare further increases the variation, since one pencil beam of incident x-ray is scattered into an area of several centimeters on the detector. In this paper, the authors study these two effects by measuring the focal spot distribution with a pinhole assembly and the detector point spread function (PSF) with an edge-spread function method. The authors then derive a formula to estimate the I{sub 0} value for different illumination field sizes, using the measured focal spot distribution and the detector PSF. Phantom studies are carried out to investigate the accuracy of scatter measurements and CT images with and without considering the I{sub 0} variation effects. Results: On our tabletop system with a Varian Paxscan 4030CB flat-panel detector and a Varian RAD-94 x-ray tube as used on a clinical CBCT system, the focal spot distribution has a measured full-width-at-half-maximum (FWHM) of around 0.4 mm, while non-negligible off-focal-spot radiation is observed at a distance of over 2 mm from the center. The measured detector PSF has an FWHM of 0.510 mm, with a shape close to Gaussian. From these two distributions, the author calculate the estimated I{sub 0} values at different collimator settings. The I{sub 0} variation mainly comes from the focal spot effect. The estimation matches well with the measurements at different collimator widths in both horizontal and vertical directions, with an average error of less than 3%. Our method improves the accuracy of conventional scatter measurements, where the scatter is measured as the difference between fan-beam and cone-beam projections. On a uniform water cylinder phantom, more accurate I{sub 0} suppresses the unfaithful high-frequency signals at the object boundaries of the measured scatter, and the SPR estimation error is reduced from 0.158 to 0.014. The proposed I{sub 0} estimation also reduces the reconstruction error from about 20 HU on the Catphan Copyright-Sign 600 phantom in the selected regions of interest to less than 4 HU. Conclusions: The I{sub 0} variation is identified as one additional error source in x-ray imaging. By measuring the focal-spot distribution and detector PSF, the authors propose an accurate method of estimating the I{sub 0} value for different illumination field sizes. The method obtains more accurate scatter measurements and therefore facilitates scatter correction algorithm designs. As correction methods for other CBCT artifacts become more successful, our research is significant in further improving the CBCT imaging accuracy.

  18. 3D Magnetic Field Effects in an NSC KIPT Compact Intense X-ray Generator

    SciTech Connect

    Zelinsky, A.; Mytsykov, A.

    2004-05-12

    The new generation of the intense X-rays sources based on low energy electron storage ring and Compton scattering of intense laser beam allows to produce hard X-rays with intensity up to 1014 phot/s. One of the main traits of a storage ring lattice for such generator type is using of magnetic elements with combined focusing functions such as bending magnets with quadrupole and sextupole field components. In combination with very low bending radius and dense magnetic elements setting along ring circumference it leads to increasing of 3D magnetic field effects on electron beam dynamics and can decrease generated radiation intensity drastically. The article is devoted to the investigations of the effects of 3D magnetic fields on bending magnet edges and lattice lenses interference on electron beam dynamics and parameters of produced radiation for NSC KIPT 225 MeV storage ring.

  19. X-ray beam method for displacement measurement in hostile environments

    NASA Technical Reports Server (NTRS)

    Jordan, Eric H.; Pease, D. M.; Canistraro, H.; Brew, Dale

    1989-01-01

    A new method of extensometry using an X-ray beam was devised, and the results of current testing reveal it to be highly feasible. This technique has been shown to provide a non-contacting system that is immune to problems associated with density variations in gaseous environments, that plague currently available optical methods. This advantage is a result of the non-refracting penetrating nature of X-rays. The method is based on X-ray-induced X-ray fluorescence of targets, which subsequently serve as fudicial markers. Some target materials have melting points over 1600 degrees C which will facilitate measurement at extremely high temperatures. A highly focused intense X-ray beam, which is produced using a Johansen 'bent crystal', is then scanned across the target, which responds by fluorescing X-rays when stimulated by the incident beam. This secondary radiation is monitored using a detector. By carefully measuring beam orientation, change in target edge position can be determined. Many variations on this basic theme are now possible such as two targets demarcating a gage length, or a beam shadowing method using opaque targets.

  20. Investigating dynamics of complex system irradiated by intense x-ray free electron laser pulses

    NASA Astrophysics Data System (ADS)

    Fang, L.; Jurek, Z.; Osipov, T.; Murphy, B. F.; Santra, R.; Berrah, N.

    2015-04-01

    We carried out experimental and theoretical investigation of the response of a complex molecule, C60, to intense x-ray photon beam from a free-electron-laser. We show good agreement between the modelling and the experiment. Our model, which can be scaled well to larger systems, reveals femotosecond molecular dynamics details, at the level of atomic resolution, which are inaccessible directly by our experiments. Our results illustrate the variety of physical and chemical processes in the interaction between large molecules and intense x- ray pulses, including photoelectric effect, secondary ionization, recombination and inter-atomic Auger decays. The understanding of these processes has a broad impact on research that implements intense x-ray pulses.

  1. Beam optics of exploding foil plasma X-ray lasers

    NASA Astrophysics Data System (ADS)

    London, Richard A.

    1988-01-01

    In solf x-ray lasers, amplification is achieved as the x-rays propagate down a long narrow plasma column. Refraction, due to electron density gradients, tends to direct the x-rays out of high density regions. This can have the undesirable effect of shortening the distance that the x-rays stay within the plasma, thereby limiting the amount of amplification. The exploding foil design lessens refraction, but does not eliminate it. In this paper, a quantitative analysis of propagation and amplification in an exploding foil x-ray laser is presented. The density and gain profiles within the plasma are modeled in an approximate manner, which enables considerable analytic progress. It is found that refraction introduces a loss term to the laser amplification. The beam pattern from a parabolic gain profile laser has a dominant peak on the x-ray laser axis. The pattern from a quartic gain profile having a dip on-axis can produce a profile with off-axis peaks, in better agreement with recent experimental data.

  2. Highly porous nanoberyllium for X-ray beam speckle suppression.

    PubMed

    Goikhman, Alexander; Lyatun, Ivan; Ershov, Petr; Snigireva, Irina; Wojda, Pawel; Gorlevsky, Vladimir; Semenov, Alexander; Sheverdyaev, Maksim; Koletskiy, Viktor; Snigirev, Anatoly

    2015-05-01

    This paper reports a special device called a `speckle suppressor', which contains a highly porous nanoberyllium plate squeezed between two beryllium windows. The insertion of the speckle suppressor in an X-ray beam allows manipulation of the spatial coherence length, thus changing the effective source size and removing the undesirable speckle structure in X-ray imaging experiments almost without beam attenuation. The absorption of the nanoberyllium plate is below 1% for 1 mm thickness at 12 keV. The speckle suppressor was tested on the ID06 ESRF beamline with X-rays in the energy range from 9 to 15 keV. It was applied for the transformation of the phase-amplitude contrast to the pure amplitude contrast in full-field microscopy. PMID:25931099

  3. Highly porous nanoberyllium for X-ray beam speckle suppression

    PubMed Central

    Goikhman, Alexander; Lyatun, Ivan; Ershov, Petr; Snigireva, Irina; Wojda, Pawel; Gorlevsky, Vladimir; Semenov, Alexander; Sheverdyaev, Maksim; Koletskiy, Viktor; Snigirev, Anatoly

    2015-01-01

    This paper reports a special device called a speckle suppressor, which contains a highly porous nanoberyllium plate squeezed between two beryllium windows. The insertion of the speckle suppressor in an X-ray beam allows manipulation of the spatial coherence length, thus changing the effective source size and removing the undesirable speckle structure in X-ray imaging experiments almost without beam attenuation. The absorption of the nanoberyllium plate is below 1% for 1?mm thickness at 12?keV. The speckle suppressor was tested on the ID06 ESRF beamline with X-rays in the energy range from 9 to 15?keV. It was applied for the transformation of the phaseamplitude contrast to the pure amplitude contrast in full-field microscopy. PMID:25931099

  4. Interpretation of nanoparticle X-ray photoelectron intensities

    NASA Astrophysics Data System (ADS)

    Werner, Wolfgang S. M.; Chudzicki, Maksymillian; Smekal, Werner; Powell, Cedric J.

    2014-06-01

    X-ray photoelectron (XPS) intensities have been simulated for spherical core-shell nanoparticles (NPs) in different geometrical arrangements in order to investigate the validity of commonly made assumptions for the interpretation of XPS NP intensities. The single-sphere approximation is valid for a powder sample when all spatial coordinates of the NP positions are uncorrelated. Correlations along either the depth coordinate or the lateral coordinates lead to features in the angular distribution that provide information on these correlations. The XPS intensity is proportional to the surface-to-volume ratio of nanoparticles but only for NP sizes exceeding the inelastic mean free path of the photoelectrons.

  5. Interpretation of nanoparticle X-ray photoelectron intensities

    SciTech Connect

    Werner, Wolfgang S. M. Chudzicki, Maksymillian; Smekal, Werner; Powell, Cedric J.

    2014-06-16

    X-ray photoelectron (XPS) intensities have been simulated for spherical core-shell nanoparticles (NPs) in different geometrical arrangements in order to investigate the validity of commonly made assumptions for the interpretation of XPS NP intensities. The single-sphere approximation is valid for a powder sample when all spatial coordinates of the NP positions are uncorrelated. Correlations along either the depth coordinate or the lateral coordinates lead to features in the angular distribution that provide information on these correlations. The XPS intensity is proportional to the surface-to-volume ratio of nanoparticles but only for NP sizes exceeding the inelastic mean free path of the photoelectrons.

  6. X-ray divergent-beam (Kossel) technique: A review

    SciTech Connect

    Lider, V. V.

    2011-03-15

    The development of the X-ray divergent-beam (Kossel) technique over the last 50 years is traced. The fundamentals of this technique and ways to implement it experimentally are considered, and its potential for studying the real structure of crystals is analyzed in detail.

  7. Towards phasing using high X-ray intensity

    SciTech Connect

    Galli, Lorenzo; Son, Sang-Kil; Barends, Thomas R. M.; White, Thomas A.; Barty, Anton; Botha, Sabine; Boutet, Sébastien; Caleman, Carl; Doak, R. Bruce; Nanao, Max H.; Nass, Karol; Shoeman, Robert L.; Timneanu, Nicusor; Santra, Robin; Schlichting, Ilme; Chapman, Henry N.

    2015-09-30

    X-ray free-electron lasers (XFELs) show great promise for macromolecular structure determination from sub-micrometre-sized crystals, using the emerging method of serial femtosecond crystallography. The extreme brightness of the XFEL radiation can multiply ionize most, if not all, atoms in a protein, causing their scattering factors to change during the pulse, with a preferential `bleaching' of heavy atoms. This paper investigates the effects of electronic damage on experimental data collected from a Gd derivative of lysozyme microcrystals at different X-ray intensities, and the degree of ionization of Gd atoms is quantified from phased difference Fourier maps. A pattern sorting scheme is proposed to maximize the ionization contrast and the way in which the local electronic damage can be used for a new experimental phasing method is discussed.

  8. Towards phasing using high X-ray intensity.

    PubMed

    Galli, Lorenzo; Son, Sang-Kil; Barends, Thomas R M; White, Thomas A; Barty, Anton; Botha, Sabine; Boutet, Sbastien; Caleman, Carl; Doak, R Bruce; Nanao, Max H; Nass, Karol; Shoeman, Robert L; Timneanu, Nicusor; Santra, Robin; Schlichting, Ilme; Chapman, Henry N

    2015-11-01

    X-ray free-electron lasers (XFELs) show great promise for macromolecular structure determination from sub-micrometre-sized crystals, using the emerging method of serial femtosecond crystallography. The extreme brightness of the XFEL radiation can multiply ionize most, if not all, atoms in a protein, causing their scattering factors to change during the pulse, with a preferential 'bleaching' of heavy atoms. This paper investigates the effects of electronic damage on experimental data collected from a Gd derivative of lysozyme microcrystals at different X-ray intensities, and the degree of ionization of Gd atoms is quantified from phased difference Fourier maps. A pattern sorting scheme is proposed to maximize the ionization contrast and the way in which the local electronic damage can be used for a new experimental phasing method is discussed. PMID:26594370

  9. Towards phasing using high X-ray intensity

    SciTech Connect

    Galli, Lorenzo; Son, Sang -Kil; Barends, Thomas R. M.; White, Thomas A.; Barty, Anton; Botha, Sabine; Boutet, Sébastien; Caleman, Carl; Doak, R. Bruce; Nanao, Max H.; Nass, Karol; Shoeman, Robert L.; Timneanu, Nicusor; Santra, Robin; Schlichting, Ilme; Chapman, Henry N.

    2015-09-30

    X-ray free-electron lasers (XFELs) show great promise for macromolecular structure determination from sub-micrometre-sized crystals, using the emerging method of serial femtosecond crystallography. The extreme brightness of the XFEL radiation can multiply ionize most, if not all, atoms in a protein, causing their scattering factors to change during the pulse, with a preferential `bleaching' of heavy atoms. This paper investigates the effects of electronic damage on experimental data collected from a Gd derivative of lysozyme microcrystals at different X-ray intensities, and the degree of ionization of Gd atoms is quantified from phased difference Fourier maps. In conclusion, a pattern sorting scheme is proposed to maximize the ionization contrast and the way in which the local electronic damage can be used for a new experimental phasing method is discussed.

  10. Towards phasing using high X-ray intensity

    DOE PAGESBeta

    Galli, Lorenzo; Son, Sang -Kil; Barends, Thomas R. M.; White, Thomas A.; Barty, Anton; Botha, Sabine; Boutet, Sébastien; Caleman, Carl; Doak, R. Bruce; Nanao, Max H.; et al

    2015-09-30

    X-ray free-electron lasers (XFELs) show great promise for macromolecular structure determination from sub-micrometre-sized crystals, using the emerging method of serial femtosecond crystallography. The extreme brightness of the XFEL radiation can multiply ionize most, if not all, atoms in a protein, causing their scattering factors to change during the pulse, with a preferential `bleaching' of heavy atoms. This paper investigates the effects of electronic damage on experimental data collected from a Gd derivative of lysozyme microcrystals at different X-ray intensities, and the degree of ionization of Gd atoms is quantified from phased difference Fourier maps. In conclusion, a pattern sorting schememore » is proposed to maximize the ionization contrast and the way in which the local electronic damage can be used for a new experimental phasing method is discussed.« less

  11. Towards phasing using high X-ray intensity

    PubMed Central

    Galli, Lorenzo; Son, Sang-Kil; Barends, Thomas R. M.; White, Thomas A.; Barty, Anton; Botha, Sabine; Boutet, Sébastien; Caleman, Carl; Doak, R. Bruce; Nanao, Max H.; Nass, Karol; Shoeman, Robert L.; Timneanu, Nicusor; Santra, Robin; Schlichting, Ilme; Chapman, Henry N.

    2015-01-01

    X-ray free-electron lasers (XFELs) show great promise for macromolecular structure determination from sub-micrometre-sized crystals, using the emerging method of serial femtosecond crystallography. The extreme brightness of the XFEL radiation can multiply ionize most, if not all, atoms in a protein, causing their scattering factors to change during the pulse, with a preferential ‘bleaching’ of heavy atoms. This paper investigates the effects of electronic damage on experimental data collected from a Gd derivative of lysozyme microcrystals at different X-ray intensities, and the degree of ionization of Gd atoms is quantified from phased difference Fourier maps. A pattern sorting scheme is proposed to maximize the ionization contrast and the way in which the local electronic damage can be used for a new experimental phasing method is discussed. PMID:26594370

  12. Soft X-ray beam induced current technique

    NASA Astrophysics Data System (ADS)

    Watts, B.; Queen, D.; Kilcoyne, A. L. D.; Tyliszczak, T.; Hellman, F.; Ade, H.

    2009-09-01

    Direct mapping of the charge transport efficiency of polymer solar cell devices using a soft X-ray beam induced current (SoXBIC) method is described. By fabricating a polymer solar cell on an x-ray transparent substrate, we demonstrate the ability to map polymer composition and nanoscale structure within an operating solar cell device and to simultaneously measure the local charge transport efficiency via the short-circuit current. A simple model is calculated and compared to experimental SoXBIC data of a PFB:F8BT bulk-heterojunction device in order to gain greater insight into the device operation and physics.

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

    PubMed Central

    Marinelli, A.; Ratner, D.; Lutman, A. A.; Turner, J.; Welch, J.; Decker, F.-J.; Loos, H.; Behrens, C.; Gilevich, S.; Miahnahri, A. A.; Vetter, S.; Maxwell, T.J.; Ding, Y.; Coffee, R.; Wakatsuki, S.; Huang, Z.

    2015-01-01

    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 magnitude 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. PMID:25744344

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

    PubMed

    Marinelli, A; Ratner, D; Lutman, A A; Turner, J; Welch, J; Decker, F-J; Loos, H; Behrens, C; Gilevich, S; Miahnahri, A A; Vetter, S; Maxwell, T J; Ding, Y; Coffee, R; Wakatsuki, S; Huang, Z

    2015-01-01

    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 magnitude 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. PMID:25744344

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

    DOE PAGESBeta

    Marinelli, A.; Ratner, D.; Lutman, A. A.; Turner, J.; Welch, J.; Decker, F. J.; Loos, H.; Behrens, C.; Gilevich, S.; Miahnahri, A. A.; et al

    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

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

    SciTech Connect

    Marinelli, A.; Ratner, D.; Lutman, A. A.; Turner, J.; Welch, J.; Decker, F. J.; Loos, H.; Behrens, C.; Gilevich, S.; Miahnahri, A. A.; Vetter, S.; Maxwell, T. J.; Ding, Y.; Coffee, R.; Wakatsuki, S.; Huang, Z.

    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 magnitude 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.

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

    NASA Astrophysics Data System (ADS)

    Marinelli, A.; Ratner, D.; Lutman, A. A.; Turner, J.; Welch, J.; Decker, F.-J.; Loos, H.; Behrens, C.; Gilevich, S.; Miahnahri, A. A.; Vetter, S.; Maxwell, T. J.; Ding, Y.; Coffee, R.; Wakatsuki, S.; Huang, Z.

    2015-03-01

    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 magnitude 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.

  18. A simple hard x-ray ''nanoslit'' for measuring wavefront intensity

    SciTech Connect

    Takano, Hidekazu; Hashimoto, Takuto; Tsuji, Takuya; Koyama, Takahisa; Tsusaka, Yoshiyuki; Kagoshima, Yasushi

    2010-07-15

    A new method is proposed for nanoscale hard x-ray measurements. This method uses a reflection on a heavy-metal wire that functions as a single slit with a nanoscale aperture for a parallel x-ray beam. This ''nanoslit'' can be used to perform high-spatial-resolution measurements of the intensity distribution of a wavefront that diverges from an aperture. In experiments, Fresnel fringes generated by a rectangular aperture were measured using a 300-{mu}m-diameter platinum wire as the nanoslit. In these experiments, the finest fringes with a period of 26 nm could be successfully resolved.

  19. Motorized Beam Alignment of a Commercial X-ray Diffractometer

    NASA Technical Reports Server (NTRS)

    Van Zandt, Noah R.; Myers, James F.; Rogers, Richard B

    2013-01-01

    X-ray diffraction (XRD) is a powerful analysis method that allows researchers to noninvasively probe the crystalline structure of a material. This includes the ability to determine the crystalline phases present, quantify surface residual stresses, and measure the distribution of crystallographic orientations. The Structures and Materials Division at the NASA Glenn Research Center (GRC) heavily uses the on-site XRD lab to characterize advanced metal alloys, ceramics, and polymers. One of the x-ray diffractometers in the XRD lab (Bruker D8 Discover) uses three different x-ray tubes (Cu, Cr, and Mn) for optimal performance over numerous material types and various experimental techniques. This requires that the tubes be switched out and aligned between experiments. This alignment maximizes the x-ray tube s output through an iterative process involving four set screws. However, the output of the x-ray tube cannot be monitored during the adjustment process due to standard radiation safety engineering controls that prevent exposure to the x-ray beam when the diffractometer doors are open. Therefore, the adjustment process is a very tedious series of blind adjustments, each followed by measurement of the output beam using a PIN diode after the enclosure doors are shut. This process can take up to 4 hr to perform. This technical memorandum documents an in-house project to motorize this alignment process. Unlike a human, motors are not harmed by x-ray radiation of the energy range used in this instrument. Therefore, using motors to adjust the set screws will allow the researcher to monitor the x-ray tube s output while making interactive adjustments from outside the diffractometer. The motorized alignment system consists of four motors, a motor controller, and a hand-held user interface module. Our goal was to reduce the alignment time to less than 30 min. The time available was the 10-week span of the Lewis' Educational and Research Collaborative Internship Project (LERCIP) summer internship program and the budget goal was $1200. In this report, we will describe our motorization design and discuss the results of its implementation.

  20. Editorial: Focus on X-ray Beams with High Coherence

    NASA Astrophysics Data System (ADS)

    Robinson, Ian; Gruebel, Gerhard; Mochrie, Simon

    2010-03-01

    This editorial serves as the preface to a special issue of New Journal of Physics, which collects together solicited papers on a common subject, x-ray beams with high coherence. We summarize the issue's content, and explain why there is so much current interest both in the sources themselves and in the applications to the study of the structure of matter and its fluctuations (both spontaneous and driven). As this collection demonstrates, the field brings together accelerator physics in the design of new sources, particle physics in the design of detectors, and chemical and materials scientists who make use of the coherent beams produced. Focus on X-ray Beams with High Coherence Contents Femtosecond pulse x-ray imaging with a large field of view B Pfau, C M Gnther, S Schaffert, R Mitzner, B Siemer, S Roling, H Zacharias, O Kutz, I Rudolph, R Treusch and S Eisebitt The FERMI@Elettra free-electron-laser source for coherent x-ray physics: photon properties, beam transport system and applications E Allaria, C Callegari, D Cocco, W M Fawley, M Kiskinova, C Masciovecchio and F Parmigiani Beyond simple exponential correlation functions and equilibrium dynamics in x-ray photon correlation spectroscopy Anders Madsen, Robert L Leheny, Hongyu Guo, Michael Sprung and Orsolya Czakkel The Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS) Sbastien Boutet and Garth J Williams Dynamics and rheology under continuous shear flow studied by x-ray photon correlation spectroscopy Andrei Fluerasu, Pawel Kwasniewski, Chiara Caronna, Fanny Destremaut, Jean-Baptiste Salmon and Anders Madsen Exploration of crystal strains using coherent x-ray diffraction Wonsuk Cha, Sanghoon Song, Nak Cheon Jeong, Ross Harder, Kyung Byung Yoon, Ian K Robinson and Hyunjung Kim Coherence properties of the European XFEL G Geloni, E Saldin, L Samoylova, E Schneidmiller, H Sinn, Th Tschentscher and M Yurkov Fresnel coherent diffractive imaging: treatment and analysis of data G J Williams, H M Quiney, A G Peele and K A Nugent Imaging of complex density in silver nanocubes by coherent x-ray diffraction R Harder, M Liang, Y Sun, Y Xia and I K Robinson Methodology for studying strain inhomogeneities in polycrystalline thin films during in situ thermal loading using coherent x-ray diffraction N Vaxelaire, H Proudhon, S Labat, C Kirchlechner, J Keckes, V Jacques, S Ravy, S Forest and O Thomas Ptychographic coherent diffractive imaging of weakly scattering specimens Martin Dierolf, Pierre Thibault, Andreas Menzel, Cameron M Kewish, Konstantins Jefimovs, Ilme Schlichting, Konstanze von Knig, Oliver Bunk and Franz Pfeiffer Dose requirements for resolving a given feature in an object by coherent x-ray diffraction imaging Andreas Schropp and Christian G Schroer FLASH: new opportunities for (time-resolved) coherent imaging of nanostructures R Treusch and J Feldhaus Structure of a single particle from scattering by many particles randomly oriented about an axis: toward structure solution without crystallization? D K Saldin, V L Shneerson, M R Howells, S Marchesini, H N Chapman, M Bogan, D Shapiro, R A Kirian, U Weierstall, K E Schmidt and J C H Spence Analysis of strain and stacking faults in single nanowires using Bragg coherent diffraction imaging V Favre-Nicolin, F Mastropietro, J Eymery, D Camacho, Y M Niquet, B M Borg, M E Messing, L-E Wernersson, R E Algra, E P A M Bakkers, T H Metzger, R Harder and I K Robinson Coherent science at the SwissFEL x-ray laser B D Patterson, R Abela, H-H Braun, U Flechsig, R Ganter, Y Kim, E Kirk, A Oppelt, M Pedrozzi, S Reiche, L Rivkin, Th Schmidt, B Schmitt, V N Strocov, S Tsujino and A F Wrulich Energy recovery linac (ERL) coherent hard x-ray sources Donald H Bilderback, Joel D Brock, Darren S Dale, Kenneth D Finkelstein, Mark A Pfeifer and Sol M Gruner Statistical and coherence properties of radiation from x-ray free-electron lasers E L Saldin, E A Schneidmiller and M V Yurkov Microscopic return point memory in Co/Pd multilayer films K A Seu, R Su, S Roy, D Parks, E Shipton, E E Fullerton and S D Kevan Holographic and diffractive x-ray imaging using waveguides as quasi-point sources K Giewekemeyer, H Neubauer, S Kalbfleisch, S P Krger and T Salditt Mapping the conformations of biological assemblies P Schwander, R Fung, G N Phillips Jr and A Ourmazd Imaging the displacement field within epitaxial nanostructures by coherent diffraction: a feasibility study Ana Diaz, Virginie Chamard, Cristian Mocuta, Rogerio Magalhes-Paniago, Julian Stangl, Dina Carbone, Till H Metzger and Gnther Bauer The potential for two-dimensional crystallography of membrane proteins at future x-ray free-electron laser sources Cameron M Kewish, Pierre Thibault, Oliver Bunk and Franz Pfeiffer Coherence properties of hard x-ray synchrotron sources and x-ray free-electron lasers I A Vartanyants and A Singer Coherent imaging of biological samples with femtosecond pulses at the free-electron laser FLASH A P Mancuso, Th Gorniak, F Staier, O M Yefanov, R Barth, C Christophis, B Reime, J Gulden, A Singer, M E Pettit, Th Nisius, Th Wilhein, C Gutt, G Grbel, N Guerassimova, R Treusch, J Feldhaus, S Eisebitt, E Weckert, M Grunze, A Rosenhahn and I A Vartanyants

  1. Coherent Cone-Beam X-ray Microscopy

    SciTech Connect

    Harder, R.; Xiao, X.

    2011-09-09

    A novel full-field imaging method using the (111) Bragg diffraction of a sub-micron gold crystal as the divergent cone-beam for sample illumination is reported. The divergence of the illumination allows for very high magnification, limited only by the achievable ratio of the crystal-to-sample and sample-to-detector distances. In this case an x-ray magnification of approximately 115 was achieved.

  2. Phase oscillations in lead monoxide under the X-ray beam

    NASA Astrophysics Data System (ADS)

    Schoonover, J. R.

    1992-10-01

    Time-resolved X-ray diffraction is used to examine phase oscillations in the lead monoxide system. The X-ray beam maintains the system far from equilibrium by producing highly disordered metastable lead monoxide. Experimentally determined logistics maps indicate that a minimum of three phases are required for the oscillations. One phase is a disordered phase, the other are commensurate and incommensurate phases in different diffraction domains. The oscillations are postulated to occur between the crystalline phases and the disordered phase. The kinetics are modeled as quasiperiodic for three or more phases, one disordered and two or more crystalline. The model predicts temperature, X-ray beam intensity, and defect dependence, but does not account for nonlinear effects.

  3. Photometry of Two Intense Low Mass X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Wachter, S.; Margon, B.; Anderson, S.

    1995-12-01

    The intense galactic X-ray source GX349+2 (Sco X-2) belongs to the class of persistently bright low-mass X-ray binaries called Z-sources. GX349+2 has only recently been optically identified with a 19th mag star. Of the six known Z-sources, only two (Sco X-1 and Cyg X-2) have been studied in the optical. It has been suggested that Z-sources as a group are characterized by evolved companions and correspondingly long orbital periods (Sco X-1, P=0.8d; Cyg X-2, P=9.8d). Recently Southwell et al. have presented spectroscopic observations of GX349+2 suggesting a 14d orbital period. We have obtained broadband photometry of the system on six consecutive nights in May 1995, and find evidence for a 21.7 +/- 0.3hr period of 0.14 mag half-amplitude, superposed on erratic flickering typical of Sco X-1 type objects. As with other Z-sources, caution will be needed to insure that the variations are truly periodic, and not simply due to chaotic variability observed over a relatively short time span. If our period is confirmed, then the nature of the 14d spectroscopic variation found by Southwell et al. is unclear. GX13+1 is a bright X-ray burst source, located in the galactic bulge. Due to heavy obscuration, no optical counterpart brighter than R ~ 22 has been detected, but an infrared counterpart (K=12) has recently been identified by Naylor et al. (1991) based on spatial coincidence with an accurate radio position. GX13+1 is unusual as there is a disagreement over its classification. Studies of the X-ray time variability place it among the Atoll-sources. However, there is some evidence that the system contains a giant companion (Garcia et al. 1992) which would place it among the Z-sources. In an attempt to determine the period of the system, we observed GX13+1 for 9 days in May -- July 1995. Preliminary photometry confirms variability of ~ 0.4 mag on a timescale of several days, as previously discovered by Charles & Naylor (1992). If GX13+1 is found to have a large orbital period, it would be indicative of a giant companion, and thus challenge the distinction between Atoll- and Z-sources on the basis of orbital and evolutionary characteristics.

  4. L X-ray Intensity Ratios in Pb With Protons

    SciTech Connect

    Mohan, Harsh; Jain, Arvind Kumar; Sharma, Sunita

    2009-03-10

    Accelerators play a significant role in the investigation of inner-shell ionization. Inner-shell excitation through the impact of protons has shown renewed interest recently. These studies indicate that in the case of L-shell ionization, most of the experiments have been conducted with protons having energies greater than 500 keV. Thus, there is not only a lack of experimental data but there also exists large discrepancies between the experimental measurements and the theoretical calculations based on different models prevailing in this energy regime. In view of this, we report in this paper the experimentally measured values of L X-ray intensity ratios for Pb, namely, L{sub l}/L{sub {alpha}}, L{sub {beta}}/L{sub {alpha}} and L{sub {gamma}}/L{sub {alpha}} with protons over the energy range 225 keV-400 keV using a Van de Graaff accelerator. Their energy dependence and comparison with theoretical calculations will also be discussed. These measurements have yielded data in the low energy region, which helps in the emergence of better understanding of proton induced X-ray emission phenomenon.

  5. 21 CFR 892.1610 - Diagnostic x-ray beam-limiting device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic x-ray beam-limiting device. 892.1610... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1610 Diagnostic x-ray beam-limiting device. (a) Identification. A diagnostic x-ray beam-limiting device is a device such as a collimator,...

  6. 21 CFR 892.1610 - Diagnostic x-ray beam-limiting device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Diagnostic x-ray beam-limiting device. 892.1610... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1610 Diagnostic x-ray beam-limiting device. (a) Identification. A diagnostic x-ray beam-limiting device is a device such as a collimator,...

  7. 21 CFR 892.1610 - Diagnostic x-ray beam-limiting device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Diagnostic x-ray beam-limiting device. 892.1610... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1610 Diagnostic x-ray beam-limiting device. (a) Identification. A diagnostic x-ray beam-limiting device is a device such as a collimator,...

  8. 21 CFR 892.1610 - Diagnostic x-ray beam-limiting device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Diagnostic x-ray beam-limiting device. 892.1610... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1610 Diagnostic x-ray beam-limiting device. (a) Identification. A diagnostic x-ray beam-limiting device is a device such as a collimator,...

  9. 21 CFR 892.1610 - Diagnostic x-ray beam-limiting device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Diagnostic x-ray beam-limiting device. 892.1610... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1610 Diagnostic x-ray beam-limiting device. (a) Identification. A diagnostic x-ray beam-limiting device is a device such as a collimator,...

  10. A compact and portable X-ray beam position monitor using Medipix3

    NASA Astrophysics Data System (ADS)

    Rico-Alvarez, O.; Kachatkou, A.; Marchal, J.; Willis, B.; Sawhney, K.; Tartoni, N.; van Silfhout, R. G.

    2014-12-01

    The present work reports on the design and implementation of a novel portable X-ray beam diagnostics (XBPM) device. The device is transparent to the X-ray beam and provides real-time measurements of beam position, intensity, and size. The measurement principle is based on a pinhole camera which records scattered radiation from a Kapton foil which is placed in the beam path. The use of hybrid detectors (Medipix3) that feature a virtually noiseless readout system with capability of single photon detection and energy resolving power enables the diagnostics with a better resolution and higher sensitivity compared to the use of traditional indirect X-ray detection schemes. We describe the detailed system design, which consists of a vacuum compatible focal plane sensor array, a sensor conditioning and readout board and a heterogeneous data processing unit, which also acts as a network server that handles network communications with clients. The readout protocol for the Medipix3 sensor is implemented using field programmable gate array (FPGA) logic resulting in a versatile and scalable system that is capable of performing advanced functions such as data compression techniques and feature extraction. For the system performance measurements, we equipped the instrument with a single Medipix3 die, bump bonded to a Si sensor, rather than four for which it was designed. Without data compression, it is capable of acquiring magnified images and profiles of synchrotron X-ray beams at a transfer rate through Ethernet of 27 frames/s for one Medipix3 die.

  11. Measurements of fusion reactions of low-intensity radioactive carbon beams on 12C and their implications for the understanding of X-ray bursts.

    PubMed

    Carnelli, P F F; Almaraz-Calderon, S; Rehm, K E; Albers, M; Alcorta, M; Bertone, P F; Digiovine, B; Esbensen, H; Niello, J O Fernndez; Henderson, D; Jiang, C L; Lai, J; Marley, S T; Nusair, O; Palchan-Hazan, T; Pardo, R C; Paul, M; Ugalde, C

    2014-05-16

    The interaction between neutron-rich nuclei plays an important role for understanding the reaction mechanism of the fusion process as well as for the energy production through pycnonuclear reactions in the crust of neutron stars. We have performed the first measurements of the total fusion cross sections in the systems (10,14,15)C+(12)C using a new active target-detector system. In the energy region accessible with existing radioactive beams, a good agreement between the experimental and theoretical cross sections is observed. This gives confidence in our ability to calculate fusion cross sections for systems which are outside the range of today's radioactive beam facilities. PMID:24877935

  12. Low intensity X-ray and gamma-ray spectrometer

    NASA Technical Reports Server (NTRS)

    Yin, L. I. (inventor)

    1982-01-01

    A low intensity X-ray and gamma ray spectrometer for imaging, counting, and energy resolving of single invisible radiation particles is described. The spectrometer includes a converting device for converting single invisible radiation particles to visible light photons. Another converting device converts the visible light photons to photoelectrons. A fiber optics coupling device couples together the two converting devices. An intensifying device intensifies the photoelectrons by an average gain factor of between 10 to the 4th power and 10 to the 7th power. The tensifying device is an anti-ion feedback microchannel plate amplifier which is operated substantially below saturation. A displaying device displays the intensified photoelectrons. The displaying device 32 indicates the spatial position, number, and energy of the incoming single invisible radiation particles.

  13. X-ray beam compression by tapered waveguides

    NASA Astrophysics Data System (ADS)

    Chen, H.-Y.; Hoffmann, S.; Salditt, T.

    2015-05-01

    We have fabricated linear tapered waveguide channels filled with air and imbedded in silicon for the hard x-ray regime, using a processing scheme involving e-beam lithography, reactive ion etching, and wafer bonding. Beam compression in such channels is demonstrated by coupling a pre-focused undulator beam into the channels, and recording the exit flux and far-field diffraction patterns. We achieved a compressed beam with a spot size of 16.48 nm (horizontal) 14.6 nm (vertical) near the waveguide exit plane, as determined from the reconstructed near-field distribution, at an exit flux which is eight times higher than that of an equivalent straight channel. Simulations indicate that this gain could reach three to four orders of magnitude for longer channels with tapering in two directions.

  14. X-ray beam compression by tapered waveguides

    SciTech Connect

    Chen, H.-Y. E-mail: tsaldit@gwdg.de; Hoffmann, S.; Salditt, T. E-mail: tsaldit@gwdg.de

    2015-05-11

    We have fabricated linear tapered waveguide channels filled with air and imbedded in silicon for the hard x-ray regime, using a processing scheme involving e-beam lithography, reactive ion etching, and wafer bonding. Beam compression in such channels is demonstrated by coupling a pre-focused undulator beam into the channels, and recording the exit flux and far-field diffraction patterns. We achieved a compressed beam with a spot size of 16.48 nm (horizontal) × 14.6 nm (vertical) near the waveguide exit plane, as determined from the reconstructed near-field distribution, at an exit flux which is eight times higher than that of an equivalent straight channel. Simulations indicate that this gain could reach three to four orders of magnitude for longer channels with tapering in two directions.

  15. Tolerance of Arteries to Microplanar X-Ray Beams

    SciTech Connect

    Sanden, Boudewijn van der; Braeuer-Krisch, Elke; Siegbahn, Erik Albert; Ricard, Clement; Vial, Jean-Claude; Laissue, Jean

    2010-08-01

    Purpose: The purpose is to evaluate effects of a new radiotherapy protocol, microbeam radiation therapy, on the artery wall. In previous studies on animal models, it was shown that capillaries recover well from hectogray doses of X-rays delivered in arrays of narrow ({<=}50 {mu}m) beams with a minimum spacing of 200 {mu}m. Here, short- and long-term effects of comparable microplanar beam configurations on the saphenous artery of the mouse hind leg were analyzed in situ by use of nonlinear optics and compared with histopathologic findings. Methods and Materials: The left hind leg of normal mice including the saphenous artery was irradiated by an array of 26 microbeams of synchrotron X-rays (50 {mu}m wide, spaced 400 {mu}m on center) with peak entrance doses of 312 Gy and 2,000 Gy. Results: The artery remained patent, but narrow arterial smooth muscle cell layer segments that were in the microplanar beam paths became atrophic and fibrotic in a dose-dependent pattern. The wide tunica media segments between those paths hypertrophied, as observed in situ by two-photon microscopy and histopathologically. Conclusions: Clinical risks of long-delayed disruption or occlusion of nontargeted arteries from microbeam radiation therapy will prove less than corresponding risks from broad-beam radiosurgery, especially if peak doses are kept below 3 hectograys.

  16. Characterization of low intensity X-ray imaging devices (Lixiscope)

    NASA Technical Reports Server (NTRS)

    Ferguson, G. A.

    1981-01-01

    Radioisotopic sources were used to excite the LIXISCOPE in preliminary experimental attempts to evaluate the usefulness of this instrument for industrial and medical applications. The characteristics of the LIXISCOPE when excited by x-ray produced by conventional electrically powered x-ray generators were studied. The optimum x-ray spectrum was determined and the mode of operation of the generator, which yields satisfactory LIXISCOPE images of medical and industrial specimens was investigated.

  17. The effects of laser beam non-uniformities on x-ray conversion efficiency

    SciTech Connect

    Langer, S.H.; Estabrook, K.G.

    1990-11-05

    High gain Inertial Confinement Fusion (ICF) targets require a highly uniform drive. In the case of direct drive, the inherent non-uniformities in a high-power glass laser beam are large enough to prevent high compression of targets. In recent years two methods for smoothing the laser drive, Induced Spatial Incoherence (ISI) and Smoothing by Spectral Dispersion (SSD), have been proposed. Both methods break the original laser beam up into many beamlets that then interfere at the target to produce an illumination pattern with large instantaneous intensity variations over a wide range of spatial scales. This interferences pattern dances around at the coherence time of the laser and averages out to produce a smooth beam on longer time scales. Indirect drive schemes shine the laser on high-Z material, usually gold, which converts the laser energy into x-rays. The x-rays are then used to drive the target. Non-uniformities in the laser beam can imprint themselves on the emitted x-rays and potentially cause problems, although the spatial transport of the x-rays to the target tends to smooth out these non-uniformities. As a result, ISI and SSD schemes are also being considered for indirect drive laser systems. We address this problem by modeling the effects on the x-ray conversion efficiency of shining a laser beam with a sinusoidal intensity modulation on a gold slab. Our principal results are that electron heat transport is quite efficient in smoothing out non-uniformities in the laser deposition before they reach the ablation surface if the spatial scale of the laser modulation is less than roughly 500 {mu}m. We also show that the gold plasma is below the Raman and Brillouin thresholds throughout the pulse.

  18. Calibration of a gated flat field spectrometer as a function of x-ray intensity.

    PubMed

    Xiong, Gang; Yang, Guohong; Li, Hang; Zhang, Jiyan; Zhao, Yang; Hu, Zhimin; Wei, Minxi; Qing, Bo; Yang, Jiamin; Liu, Shenye; Jiang, Shaoen

    2014-04-01

    We present an experimental determination of the response of a gated flat-field spectrometer at the Shenguang-II laser facility. X-rays were emitted from a target that was heated by laser beams and then were divided into different intensities with a step aluminum filter and collected by a spectrometer. The transmission of the filter was calibrated using the Beijing Synchrotron Radiation Facility. The response characteristics of the spectrometer were determined by comparing the counts recorded by the spectrometer with the relative intensities of the x-rays transmitted through the step aluminum filter. The response characteristics were used to correct the transmission from two shots of an opacity experiment using the same samples. The transmissions from the two shots are consistent with corrections, but discrepant without corrections. PMID:24784590

  19. Calibration of a gated flat field spectrometer as a function of x-ray intensity

    SciTech Connect

    Xiong, Gang; Yang, Guohong; Li, Hang; Zhang, Jiyan Zhao, Yang; Hu, Zhimin; Wei, Minxi; Qing, Bo; Yang, Jiamin; Liu, Shenye; Jiang, Shaoen

    2014-04-15

    We present an experimental determination of the response of a gated flat-field spectrometer at the Shenguang-II laser facility. X-rays were emitted from a target that was heated by laser beams and then were divided into different intensities with a step aluminum filter and collected by a spectrometer. The transmission of the filter was calibrated using the Beijing Synchrotron Radiation Facility. The response characteristics of the spectrometer were determined by comparing the counts recorded by the spectrometer with the relative intensities of the x-rays transmitted through the step aluminum filter. The response characteristics were used to correct the transmission from two shots of an opacity experiment using the same samples. The transmissions from the two shots are consistent with corrections, but discrepant without corrections.

  20. Calibration of a gated flat field spectrometer as a function of x-ray intensity

    NASA Astrophysics Data System (ADS)

    Xiong, Gang; Yang, Guohong; Li, Hang; Zhang, Jiyan; Zhao, Yang; Hu, Zhimin; Wei, Minxi; Qing, Bo; Yang, Jiamin; Liu, Shenye; Jiang, Shaoen

    2014-04-01

    We present an experimental determination of the response of a gated flat-field spectrometer at the Shenguang-II laser facility. X-rays were emitted from a target that was heated by laser beams and then were divided into different intensities with a step aluminum filter and collected by a spectrometer. The transmission of the filter was calibrated using the Beijing Synchrotron Radiation Facility. The response characteristics of the spectrometer were determined by comparing the counts recorded by the spectrometer with the relative intensities of the x-rays transmitted through the step aluminum filter. The response characteristics were used to correct the transmission from two shots of an opacity experiment using the same samples. The transmissions from the two shots are consistent with corrections, but discrepant without corrections.

  1. Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

    SciTech Connect

    Sutter, John P. Dolbnya, Igor P.; Collins, Stephen P.; Harris, Kenneth D. M.; Edwards-Gau, Gregory R.; Palmer, Benjamin A.

    2015-04-28

    In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

  2. Conceptual design study of an intense x-ray source for coronary angiography

    SciTech Connect

    Blumberg, L.N.

    1992-03-01

    Calculations are presented for several 1.4 GeV electron storage ring designs which, with an ultra-high field (80 kG) superconducting wiggler magnet and beam current I = 400 mA, will generate a 33.16 keV x-ray beam at 20 m from the wiggler of adequate intensity (6 10{sup 9}/mm{sup {minus}2} sec{sup {minus}1}) and areal size for iodine K-edge coronary dichromography in humans.

  3. Development of a Scanning X-ray Fluorescence Microscope Using Size-Controllable Focused X-ray Beam from 50 to 1500nm

    SciTech Connect

    Matsuyama, Satoshi; Mimura, Hidekazu; Yumoto, Hirokatsu; Katagishi, Keiko; Handa, Soichiro; Shibatani, Akihiko; Sano, Yasuhisa; Yamauchi, Kazuto; Yamamura, Kazuya; Endo, Katsuyoshi; Mori, Yuzo; Nishino, Yoshinori; Tamasaku, Kenji

    2007-01-19

    In scanning X-ray microscopy, focused beam intensity and size are very important from the viewpoints of improvements of various performances such as sensitivity and spatial resolution. The K-B mirror optical system is considered to be the most promising method for hard X-ray focusing, allowing highly efficient and energy-tunable focusing. We developed focusing optical system using K-B mirrors where the focused beam size is controllable within the range of 50 - 1500 nm. The focused beam size and beam intensity can be adjusted by changing the source size, although beam intensity and size are in a trade-off relationship. This controllability provides convenience for microscopy application. Diffraction limited focal size is also achieved by setting the source size to 10 {mu}m. Intracellular elemental mappings at the single-cell level were performed to demonstrate the performance of the scanning X-ray fluorescence microscope equipped with the optical system at the BL29XUL of SPring-8. We will show magnified elemental images with spatial resolution of {approx}70 nm.

  4. Femtosecond laser-driven intense Cu K α X-ray source with a novel film target driver

    NASA Astrophysics Data System (ADS)

    Lee, Sungman; Choi, Il Woo; Sohn, Ik-Bu; Lee, Kitae; Shim, Gyu Il; Jeong, Young Uk; Han, Byung Heon; Ryu, Woo Je; Kim, Ha-Na; Cha, Hyungki

    2015-09-01

    A laser-induced intense Ka hard X-ray source was developed by using a novel copper film target and a 27-TW femtosecond laser system. A specially designed pinhole camera was employed to measure the X-ray photon flux, X-ray energy spectrum, and X-ray source image. By adapting a single photon counting method, we estimated the photon number in the full width at half maximum (FWHM) spectral region to be 1.74 × 109 photons/sr for 8.05-keV Cu Ka X-rays. The shape of the X-ray source was matched well with that of the focused laser beam on the target. By provision of a lengthy copper film of 50 m with a thickness of 50 µm, the novel copper film target is capable of long time operation of more than 27 hours at a repetition rate of 10 Hz. The hard X-ray source is suitable for applications in single-shot X-ray contrast imaging or in ultrafast pump-probe analyses of material structures.

  5. Study of ion beam mixing in C/Si multilayers by X-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Asokan, K.; Srivastava, S. K.; Kabiraj, D.; Mookerjee, S.; Avasthi, D. K.; Jan, J. C.; Chiou, J. W.; Pong, W. F.; Ting, L. C.; Chien, F. Z.

    2002-06-01

    The C/Si multilayers were prepared by electron beam evaporation in a cryo-pumped vacuum deposition system. These were characterized by X-ray diffraction before and after high-energy heavy ion, 120 MeV Au, irradiation. Soft X-ray absorption spectra in the C K-edge region were measured using synchrotron radiation to identify the chemical bonding states of the Si and C. This study indicates that ion beam mixing induces SiC phase and carbon clusters. A significant increase in the intensity of pre-edge peak of C K-edge, assigned to ? ?, is observed in the irradiated C/Si multilayer sample. It is intriguing to note such sharp increase in intensity after irradiation that may be associated with the effect of large electronic excitation energy transferred by energetic Au ions.

  6. Food Irradiation Using Electron Beams and X-Rays

    NASA Astrophysics Data System (ADS)

    Miller, Bruce

    2003-04-01

    In this presentation we will discuss the technology of food irradiation using electron accelerators. Food irradiation has generally come to describe the use of ionizing radiation to decrease the population of, or prevent the growth of, undesirable biological organisms in food. The many beneficial applications include insect disinfestation, sprouting inhibition, delayed ripening, and the enhanced safety and sterilization of fresh and frozen meat products, seafood, and eggs. With special regard to food safety, bacteria such as Salmonella enteridis, Listeria monocytogenes, Campylobacter jejuni and Escherichia coli serotype O157:H7 are the primary causes of food poisoning in industrialized countries. Ionizing doses in the range of only 1-5 kilogray (kGy) can virtually eliminate these organisms from food, without affecting the food's sensory and nutritional qualities, and without inducing radioactivity. The key elements of an accelerator-based irradiation facility include the accelerator system, a scanning system, and a material handling system that moves the product through the beam in a precisely controlled manner. Extensive radiation shielding is necessary to reduce the external dose to acceptable levels, and a safety system is necessary to prevent accidental exposure of personnel during accelerator operation. Parameters that affect the dose distribution must be continuously monitored and controlled with process control software. The choice of electron beam vs x-ray depends on the areal density (density times thickness) of the product and the anticipated mass throughput. To eliminate nuclear activation concerns, the maximum kinetic energy of the accelerator is limited by regulation to 10 MeV for electron beams, and 5 MeV for x-rays. From penetration considerations, the largest areal density that can be treated by double-sided electron irradiation at 10 MeV is about 8.8 g/cm2. Products having greater areal densities must be processed using more penetrating x-rays. The mass throughput (dM/dt in kg/s) of an accelerator-based system is proportional to the average beam power (P in kW), and inversely proportional to the minimum required dose (Dm in kGy, with 1 kGy = 1 kJ/kg). The constant of proportionality is the mass throughput efficiency. Throughput efficiencies of 0.4 or better are typical of electron beam installations, but are only 0.025-0.035 for x-ray installations, primarily because of the inefficiency of bremsstrahlung generation at 5 MeV (about 8an axially-coupled, standing-wave, L-band linac with an average power in excess of 100 kW to achieve reasonable throughput rates with x-ray processing. Various design aspects of this new machine will be presented.

  7. Eye sparing in high energy x ray beams

    SciTech Connect

    Galbraith, D.M.; Aget, H.; Leung, P.M.K.; Rider, W.D.

    1985-03-01

    Treatment of cancer of the antrum and nasopharynx often includes the radiation of tissues close to an uninvolved eye. One treatment method consists of using an anterior high energy X ray beam directed to the tumor through the eye. To maintain a high dose adjacent to and behind the eye while reducing the entrance dose to the eye, build-up material is placed on the skin and a tunnel cut through to the eye. When the build-up material is tissue-like, the tunnel can be several centimeters in height and scattered radiation from the tunnel walls will largely offset the build-up material, the dose to the superficial layers of the eye can be reduced almost to the limit set by the open beam characteristics. This technique has been used successfully for 8 years.

  8. Beamed X-rays in radio-loud quasars

    NASA Astrophysics Data System (ADS)

    Buhler, P.; Courvoisier, T. J.-L.; Staubert, R.

    1994-07-01

    The X-ray spectra of radio-loud quasars are considerably steeper in the ROSAT PSPC band (0.1-2.4 keV) than in the slightly harder Einstein IPC band (0.3-3.5 keV). In order to explain this fact Jackson et al. (1993) simulated PSPC and IPC observations of a beaming model spectrum (Browne & Murphy 1987) plus a soft power law component. Whereas they succeeded to reproduce the observed steep ROSAT spectra, their simulated Einstein spectra were too steep. They therefore concluded that the concept of the beaming model might be wrong. With the help of a PSPC observation of 3C273 we show that the assumed shape of the soft component could be the origin of this failure.

  9. Mistakes encountered during automatic peak identification in low beam energy X-ray microanalysis.

    PubMed

    Newbury, Dale E

    2007-01-01

    Automated peak identification in electron beam excited X-ray microanalysis with energy dispersive X-ray spectrometry (EDS) is subject to occasional mistakes even on well-separated, high-intensity peaks arising from major constituents. The problem is exacerbated when analysis conditions are restricted to operation in the "low beam energy scanning electron microscopy" (i.e. "low voltage scanning electron microscopy" or LVSEM) regime where the incident beam energy is 5 keV or less. These low beam energy microanalysis conditions force the analyst to use low fluorescence yield L-shell and M-shell peaks rather than higher yield K-shell and L-shell peaks typically selected for elements of intermediate and high atomic number under conventional high beam energy (>10 keV) conditions. Misidentifications can arise in automated peak identification procedures when only a single energy channel is used to characterize an EDS peak. The effect of the EDS measurement process is to convolve the closely spaced Lalpha-Lbeta and Malpha-Mbeta peaks into a single peak with a peak channel shift of 20 eV or more from the Lalpha or Malpha value, which is typically sought in an X-ray database. An extensive list of problem situations encountered in low beam energy microanalysis is presented based upon observed peak identification mistakes as well as likely troublesome situations based upon proximity in peak energy. Robust automatic peak identification requires implementation of peak fitting that utilizes the full peak shape. PMID:17676629

  10. An experimental measurement of metal multilayer x-ray reflectivity degradation due to intense x-ray flux

    SciTech Connect

    Hockaday, M.Y.P.

    1987-06-01

    The degradation of the x-ray reflection characteristics of metal multilayer Bragg diffractors due to intense x-ray flux was investigated. The Z-pinch plasma produced by PROTO II of Sandia National Laboratories, Albuquerque, New Mexico, was used as the source. The plasma generated total x-ray yields of as much as 40 kJ with up to 15 kJ in the neon hydrogen- and helium-like resonance lines in nominal 20-ns pulses. Molybdenum-carbon, palladium-carbon, and tungsten-carbon metal multilayers were placed at 15 and 150 cm from the plasma center. The multilayers were at nominal angles of 5/sup 0/ and 10/sup 0/ to diffract the neon resonance lines. The time-integrated x-ray reflection of the metal multilayers was monitored by x-ray film. A fluorescer-fiber optic-visible streak camera detector system was then used to monitor the time-resolved x-ray reflection characteristics of 135 A- 2d tungsten-carbon multilayers. A large specular component in the reflectivity prevented determination of the rocking curve of the multilayer. For a neon implosion onto a vanadium-doped polyacrylic acid foam target shot, detailed modeling was attempted. The spectral flux was determined with data from 5 XRD channels and deconvolved using the code SHAZAM. The observed decay in reflectivity was assumed to correspond to the melting of the first tungsten layer. A ''conduction factor'' of 82 was required to manipulate the heat loading of the first tungsten layer such that the time of melting corresponded to the observed decay. The power at destruction was 141 MW/cm/sup 2/ and the integrated energy at destruction was 2.0 J/cm/sup 2/. 82 refs., 66 figs., 10 tabs.

  11. Study of the angular distribution of W-L X-ray intensity ratios in photoionization

    NASA Astrophysics Data System (ADS)

    Wang, Xing; Xu, Zhongfeng; Zhang, Limin

    2016-03-01

    The angular distribution of W-Lα, Lβ1 and Lβ2 X-rays induced by 13.1 keV bremsstrahlung has been measured at different emission angles from 110∘ to 140∘ at intervals of 10∘. The investigation of angular dependence of L X-ray intensity ratios by bremsstrahlung is barely found in previous works. The Lβ1 X-ray yield shows isotropic emission, while the measured Lα and Lβ2 X-ray yields are found to be spatially anisotropic. At last, the anisotropy parameters for Lα and Lβ2 X-rays have been derived.

  12. X-ray framing camera for pulsed, high current, electron beam x-ray sources

    NASA Astrophysics Data System (ADS)

    Failor, B. H.; Rodriguez, J. C.; Riordan, J. C.; Lojewski, D. Y.

    2007-07-01

    High power x-ray sources built for nuclear weapons effects testing are evolving toward larger overall diameters and smaller anode cathode gaps. We describe a framing camera developed to measure the time-evolution of these 20-50 ns pulsed x-ray sources produced by currents in the 1.5-2.5 MA range and endpoint voltages between 0.2 and 1.5 MV. The camera has up to 4 frames with 5 ns gate widths; the frames are separated by 5 ns. The image data are recorded electronically with a gated intensified CCD camera and the data are available immediately following a shot. A fast plastic scintillator (2.1 ns decay time) converts the x-rays to visible light and, for high sensitivity, a fiber optic imaging bundle carries the light to the CCD input. Examples of image data are shown.

  13. Hiresmon: A Fast High Resolution Beam Position Monitor for Medium Hard and Hard X-Rays

    SciTech Connect

    Menk, Ralf Hendrik; Giuressi, Dario; Arfelli, Fulvia; Rigon, Luigi

    2007-01-19

    The high-resolution x-ray beam position monitor (XBPM) is based on the principle of a segmented longitudinal ionization chamber with integrated readout and USB2 link. In contrast to traditional transversal ionization chambers here the incident x-rays are parallel to the collecting field which allows absolute intensity measurements with a precision better than 0.3 %. Simultaneously the beam position in vertical and horizontal direction can be measured with a frame rate of one kHz. The precision of position encoding depends only on the SNR of the synchrotron radiation and is in the order of micro meters at one kHz frame rate and 108 photon /sec at 9 KeV.

  14. A Bragg beam splitter for hard x-ray free-electron lasers.

    PubMed

    Osaka, Taito; Yabashi, Makina; Sano, Yasuhisa; Tono, Kensuke; Inubushi, Yuichi; Sato, Takahiro; Matsuyama, Satoshi; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2013-02-11

    We report a Bragg beam splitter developed for utilization of hard x-ray free-electron lasers. The splitter is based on an ultrathin silicon crystal operating in the symmetric Bragg geometry to provide high reflectivity and transmissivity simultaneously. We fabricated frame-shaped Si(511) and (110) crystals with thicknesses below 10 ?m by a reactive dry etching method using atmospheric-pressure plasma. The thickness variation over an illuminated area is less than 300 nm peak-to-valley. High crystalline perfection was verified by topographic and diffractometric measurements. The crystal thickness was evaluated from the period of the Pendellsung beats measured with a highly monochromatic and collimated x-ray probe. The crystals provide two replica pulses with uniform wavefront [(<1/50)?] and low spatial intensity variation (<5%). These Bragg beam splitters will play an important role in innovating XFEL applications. PMID:23481739

  15. High intensity compact Compton X-ray sources: Challenges and potential of applications

    NASA Astrophysics Data System (ADS)

    Jacquet, M.

    2014-07-01

    Thanks to the exceptional development of high power femtosecond lasers in the last 15 years, Compton based X-ray sources are in full development over the world in the recent years. Compact Compton sources are able to combine the compactness of the instrument with a beam of high intensity, high quality, tunable in energy. In various fields of applications such as biomedical science, cultural heritage preservation and material science researches, these sources should provide an easy working environment and the methods currently used at synchrotrons could be largely developed in a lab-size environment as hospitals, labs, or museums.

  16. Self-regulated propagation of intense infrared pulses in elongated soft-x-ray plasma amplifiers

    NASA Astrophysics Data System (ADS)

    Oliva, Eduardo; Depresseux, Adrien; Tissandier, Fabien; Gautier, Julien; Sebban, Stéphane; Maynard, Gilles

    2015-08-01

    Increasing the electron density of collisionally pumped plasma-based soft-x-ray lasers offers promising opportunities to deliver ultrashort pulses. However, strong nonlinear effects, such as overionization-induced refraction and self-focusing, hinder the propagation of the laser beam and thus the generation of elongated volume of lasing ions to be pumped. Using a particle-in-cell code and a ray-tracing model we demonstrate that optically preformed waveguides allow for addressing those issues through a self-regulation regime between self-focusing and overionization processes. As a result, guiding intense pulses over several millimeters leads to the implementation of saturated plasma amplifiers.

  17. Constancy check of beam quality in conventional diagnostic X-ray equipment.

    PubMed

    Costa, Alessandro M; Badin, Rômulo S; Leite, Marina S; Caldas, Linda V E

    2008-10-01

    A tandem ionization chamber was developed for quality control programs of X-ray equipment used in conventional radiography and mammography. A methodology for the use of the tandem chamber in the constancy check of diagnostic X-ray beam qualities was established. The application at a medical X-ray imaging facility of this established methodology is presented. The use of the tandem chamber in the constancy check of diagnostic X-ray beam qualities is a useful method to control the performance of the X-ray equipment. PMID:18434171

  18. The X-ray Beam Passage through the Collimator Made of Different Materials: Numerical Simulation

    NASA Astrophysics Data System (ADS)

    Stuchebrov, S. G.; Miloichikova, I. A.; Danilova, I. B.

    2016-01-01

    The X-ray beam application grows in the research investigations, in the medical diagnosis and treatment, in the industry. In this paper the theoretical model of the actual pulsed X-ray generator RAP-160-5 beam developed in the program “Computer Laboratory (PCLab)” is shown. The simulation data of the X-ray beam profile and shape collimated by different materials (gypsum, corund-zirconia ceramic, lead) are illustrated.

  19. Divergence measurements of soft x-ray laser beam

    SciTech Connect

    Suckewer, S.; Skinner, C.H.; Kim, D.; Valeo, E.; Voorhees, D.; Wouters, A.

    1986-07-01

    The divergence of the CVI 182 A lasing line generated in a rapidly recombining, magnetically confined plasma column was measured using soft x-ray spectrometers equipped with multichannel detectors. In addition to measurements of the relative divergence, an absolute divergence of approx.9 mrad at a magnetic field of 20 kG and approx.5 mrad at a magnetic field of 35 or 50 kG was obtained by a direct scan of the 182 A axial radiation. Based on this data a peak 182 A intensity of approx.100 kW is obtained. Calculations of the spatial distribution of gain in the plasma were in very good agreement with the experimental data.

  20. Stereotactic breast irradiation with kilovoltage x-ray beams

    NASA Astrophysics Data System (ADS)

    Garnica-Garza, H. M.

    2016-01-01

    The purpose of this work is to determine, using Monte Carlo simulation and a realistic patient model, the characteristics of the resultant absorbed dose distributions when breast tumors are irradiated using small-field stereotactic body radiation therapy (SBRT) with kilovoltage x-ray beams instead of the standard megavoltage energies currently in use. The Rensselaer Polytechnic Institute (RPI) female phantom was used to model a pair of small-field SBRT breast treatments: in one treatment the tumor at depth and another one with the tumor located close to the breast surface. Each treatment consisted of 300 circular beams aimed at the tumor from a plurality of positions. The PENELOPE Monte Carlo code was used to determine the absorbed dose distribution for each beam and subsequently an optimization algorithm determined each beam weight according to a set of prescription goals. Both kilo- and megavoltage beam treatments were modeled, the latter to be used as a reference. Cumulative dose-volume histograms for eleven structures were used to compare the kilovoltage and reference treatments. Integral dose values are also reported. Absorbed dose distributions for the target volumes as well as the organs at risk were within the parameters reported in a clinical trial for both treatments. While for the ipsilateral healthy breast tissue the megavoltage treatment does offer an advantage in terms of less volume irradiated to intermediate doses, for the contralateral structures, breast and lung, the low penetration ability of the kilovoltage treatment results in a lower maximum dose. Skin dose is higher for the kilovoltage treatment but still well within the tolerance limits reported in the clinical trial.

  1. Stereotactic breast irradiation with kilovoltage x-ray beams.

    PubMed

    Garnica-Garza, H M

    2016-01-21

    The purpose of this work is to determine, using Monte Carlo simulation and a realistic patient model, the characteristics of the resultant absorbed dose distributions when breast tumors are irradiated using small-field stereotactic body radiation therapy (SBRT) with kilovoltage x-ray beams instead of the standard megavoltage energies currently in use. The Rensselaer Polytechnic Institute (RPI) female phantom was used to model a pair of small-field SBRT breast treatments: in one treatment the tumor at depth and another one with the tumor located close to the breast surface. Each treatment consisted of 300 circular beams aimed at the tumor from a plurality of positions. The PENELOPE Monte Carlo code was used to determine the absorbed dose distribution for each beam and subsequently an optimization algorithm determined each beam weight according to a set of prescription goals. Both kilo- and megavoltage beam treatments were modeled, the latter to be used as a reference. Cumulative dose-volume histograms for eleven structures were used to compare the kilovoltage and reference treatments. Integral dose values are also reported. Absorbed dose distributions for the target volumes as well as the organs at risk were within the parameters reported in a clinical trial for both treatments. While for the ipsilateral healthy breast tissue the megavoltage treatment does offer an advantage in terms of less volume irradiated to intermediate doses, for the contralateral structures, breast and lung, the low penetration ability of the kilovoltage treatment results in a lower maximum dose. Skin dose is higher for the kilovoltage treatment but still well within the tolerance limits reported in the clinical trial. PMID:26738938

  2. Synchrotron white-beam X-ray topography of ribonuclease S crystals.

    PubMed

    Vetter, W M; Gallagher, D T; Dudley, M

    2002-04-01

    With careful experimental design, indexed synchrotron white-beam X-ray topographs of ribonuclease S crystals at ambient temperature could be recorded with a definition and contrast comparable to that of monochromatic beam topographs of other proteins reported in the literature. By excluding wavelengths longer than 1 A from the white beam with a filter, a radiation dose equivalent to that required to record about 18 topographs could be tolerated without appreciable radiation damage to the samples. Bragg angles of 0.5 degrees or less were required to select low-index harmonically pure reflections with high intensities and extinction lengths only several times the sample's thickness. The resulting X-ray topographs in some cases showed topographic detail and in others showed the even featureless background that has been considered characteristic of a protein crystal of low mosaicity. The ribonuclease S crystals were well ordered single crystals of a quality comparable to other protein crystals that have been studied by X-ray topography. PMID:11914480

  3. Time Integrated Soft X-ray Imaging in High Intensity Laser Experiments (thesis)

    SciTech Connect

    Stafford, D

    2009-06-01

    2009 marks a significant achievement and the dawn of a new era in high intensity laser research with the final commissioning of all 192 beams at the National Ignition Facility (NIF). NIF is a department of energy (DOE) funded project more than 10 years in the making located at the Lawrence Livermore National Laboratory (LLNL). The following research was done as one of many preliminary experiments done to prepare for these historic events. The primary focus of the experimental campaign this paper addresses is to test and develop a thermal x-radiation source using a short pulse laser. This data is hoped to provide information about the thermal transport mechanisms important in the development of prediction models in High Energy Density (HED) science. One of several diagnostics fielded was a soft x-ray imager (SXRI) which is detailed in this paper. The SXRI will be used to measure the relative size of the heated region and also the relative level of specific x-ray emissions among several shot and target configurations. The laser system used was the Titan laser located in the Jupiter Laser Facility (JLF) at Lawrence Livermore National Laboratory (LLNL). Titan uses the JLF Janus Nd:glass laser west frontend system with a Optical Parametric Chirped Pulse Amplification (OPCPA) in place of the nanosecond oscillator. The system is capable of producing laser intensities of over a petawatt with several tens of joules delivered in the beam.

  4. Fracture response of several metals to fast heating of samples by intensive X-ray radiation

    NASA Astrophysics Data System (ADS)

    Golubev, Vladimir

    2015-06-01

    Results on studying the fracture response of metals samples in the form of thin disks to fast heating by the intensive pulse of X-ray radiation of a complete spectrum are presented in the paper. The samples of such metals as iron, copper, AMg6 aluminum, VT14 titanium, molybdenum, tungsten, cadmium, lead and zinc were tested. The samples were fixed in the special cartridges that were placed at such distances from the X-ray irradiator where the energy fluxes were 1.38, 0.90 and 0.29 kJ/cm2. The irradiating X-ray pulse was about 2 ns in duration. After testing, the depth of material ablation from a sample front surface and the degree and character of its spall damage were determined. The method of metallographic analysis was used for these purposes. The spectrum data were used for the calculations of samples heating. Numerical calculations of thermomechanical and shock wave loading conditions were made with the use of the equation of state taking into account the process of evaporation. The calculated value of maximum negative pressure in the sample at the coordinate corresponding to the depth of ablation and formation of spallation zones or spall cracks was conventionally accepted as the material resistance to spall fracture in such conditions. The comparison of obtained results with the data on the fracture of examined materials in the conditions of fast heating by the X-ray pulse with a hard spectrum and by the high-current electron beam of an electron pulse generator was conducted.

  5. Z pinches as intense x-ray sources for inertial confinement fusion applications

    SciTech Connect

    Matzen, M.K.

    1997-05-01

    Fast z-pinch implosions can convert more than 10% of the stored electrical energy in a pulsed-power accelerator into x-rays. On the Saturn pulsed-power accelerator at Sandia National Laboratories, currents of 6 to 8 MA with a risetime of less than 50 ns have been used to drive cylindrically-symmetric arrays of wires, producing x-ray energies greater than 400 kJ with x-ray pulsewidths less than 5 ns and peak x-ray powers of 75 {+-} 10 TW. Using similar loads, PBFA Z has produced > 1.5 MJ and > 150 TW of x-rays in the first four months of operation in the z-pinch mode. These x-ray energies and powers are records for laboratory x-ray production. The x-ray output can be thermalized into a near-Planckian x-ray source by containing it within a cylindrical radiation case (a hohlraum). These energetic, intense, large volume, long-lived hohlraum x-ray sources have recently been used for ICF-relevant ablator physics experiments and offer the potential for performing many new basic physics and fusion-relevant experiments.

  6. Time dependence of X-ray polarizability of a crystal induced by an intense femtosecond X-ray pulse

    PubMed Central

    Leonov, A.; Ksenzov, D.; Benediktovitch, A.; Feranchuk, I.; Pietsch, U.

    2014-01-01

    The time evolution of the electron density and the resulting time dependence of Fourier components of the X-ray polarizability of a crystal irradiated by highly intense femtosecond pulses of an X-ray free-electron laser (XFEL) is investigated theoretically on the basis of rate equations for bound electrons and the Boltzmann equation for the kinetics of the unbound electron gas. The photoionization, Auger process, electron-impact ionization, electronelectron scattering and three-body recombination have been implemented in the system of rate equations. An algorithm for the numerical solution of the rate equations was simplified by incorporating analytical expressions for the cross sections of all the electron configurations in ions within the framework of the effective charge model. Using this approach, the time dependence of the inner shell populations during the time of XFEL pulse propagation through the crystal was evaluated for photon energies between 4 and 12?keV and a pulse width of 40?fs considering a flux of 1012?photons pulse?1 (focusing on a spot size of ?1?m). This flux corresponds to a fluence ranging between 0.8 and 2.4?mJ?m?2. The time evolution of the X-ray polarizability caused by the change of the atomic scattering factor during the pulse propagation is numerically analyzed for the case of a silicon crystal. The time-integrated polarizability drops dramatically if the fluence of the X-ray pulse exceeds 1.6?mJ?m?2. PMID:25485121

  7. Prediction and Measurement of X-Ray Spectral and Intensity Distributions from Low Energy Electron Impact Sources

    NASA Technical Reports Server (NTRS)

    Edwards, David L.

    1999-01-01

    In-vacuum electron beam welding is a technology that NASA considered as a joining technique for manufacture of space structures. The interaction of energetic electrons with metal produces x-rays. The radiation exposure to astronauts performing the in-vacuum electron beam welding must be characterized and minimized to insure safe operating conditions. This investigation characterized the x-ray environment due to operation of an in-vacuum electron beam welding tool. NASA, in a joint venture with the Russian Space Agency, was scheduled to perform a series of welding in space experiments on board the United States Space Shuttle. This series of experiments was named the International Space Welding Experiment (ISWE). The hardware associated with the ISWE was leased to NASA, by the Paton Welding Institute (PWI) in Ukraine, for ground based welding experiments in preparation for flight. Two tests were scheduled, using the ISWE electron beam welding tool, to characterize the radiation exposure to an astronaut during the operation of the ISWE. These radiation exposure tests consisted of Thermoluminescence Dosimeters (TLD's) shielded with material currently used by astronauts during Extra Vehicular Activities (EVA) and exposed to x-ray radiation generated by operation of an in-vacuum electron beam welding tool. This investigation was the first known application of TLD's to measure absorbed dose from x-rays of energy less than 10 KeV. The ISWE hardware was returned to Ukraine before the issue of adequate shielding for the astronauts was verified. Therefore, alternate experimental and analytical methods were developed to measure and predict the x-ray spectral and intensity distribution generated by electron impact with metal. These x-ray spectra were used to calculate the absorbed radiation dose to astronauts. These absorbed dose values were compared to TLD measurements obtained during actual operation of the in-vacuum electron beam welding tool. The calculated absorbed dose values were found to be in good agreement with the TLD values.

  8. Observation of material, thickness, and bremsstrahlung x-ray intensity dependent effects in moderate and high Z targets in a gamma and x-ray LIDAR experiment

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaodong; Ayaz-Maierhafer, Birsen; Laubach, Mitchell A.; Hayward, Jason P.

    2015-06-01

    A high energy gamma and x-ray LIDAR system consisting of a fast pulse (~50 ps, FWHM) LINAC and a Cherenkov detection system was used to investigate response differences among materials, their thicknesses, and bremsstrahlung x-ray intensities. The energies and pulse width of electrons used to produce bremsstrahlung x-rays were set at 20 or 40 MeV and 50 ps FWHM duration, respectively. The Cherenkov detector was built with a fused silica glass optically coupled to a 51 mm fast timing photomultiplier tube, which has an intrinsic energy threshold of 340.7 keV for Compton backscattered gammas. Such a fast detection system yields a coincidence resolving time of 93 ps FWHM, which is equivalent to a depth resolving capability of about 3 cm FWHM. The thicknesses of iron and lead targets were varied from 1 in. to 7 in. with a step of 1 in., and the thicknesses of DU were varied from 1/3 in. to 1 in. with a step of 1/3 in. The experimental results show that iron targets tend to produce a factor of five less observed x-rays and gammas, with less energetic photoelectron frequency distributions, compared with DU and lead targets for the same beam intensity and target thicknesses. Additionally, the self-shielding effect causes the lead to yield more gammas than the DU considering the experimental observation point. For the setup used in this study, a charge per pulse in the range of 1-2.5 nC yields the best resolving capability between the DU and lead targets.

  9. A Laue-Bragg monolithic beam splitter for efficient X-ray 2-beam imaging

    NASA Astrophysics Data System (ADS)

    Oberta, P.; Mokso, R.

    2013-03-01

    Newly emerging techniques for probing matter simultaneously by two spatially and angularly separated X-ray beams require efficient and versatile beam splitting. We present a Laue-Bragg monolithic crystal beam splitter in the form of an L-shaped monolithic Si crystal. By simultaneous Laue and Bragg diffractions the X-ray beam is split into a transmitted polychromatic and a diffracted monochromatic branch with a spatial separation of tens of millimeters. The energy spectrum of the transmitted branch can be tuned via diffraction on a second crystal re-creating a beam intersection on the sample. We propose three multi-modal imaging setups exploiting the large angular separation of the two intersecting beams provided by the proposed optics. Photon efficiency and dual-energy operation are the main assets of our scheme as compared to other existing setups. The theoretical description for an energy range between 10 keV and 30 keV was developed.

  10. Synchrotron radiation x-ray beam profile monitor using chemical vapor deposition diamond film

    SciTech Connect

    Kudo, Togo; Takahashi, Sunao; Nariyama, Nobuteru; Hirono, Toko; Tachibana, Takeshi; Kitamura, Hideo

    2006-12-15

    Photoluminescence (PL) of a Si-doped polycrystalline diamond film fabricated using the chemical vapor deposition technique was employed to measure the profile of a synchrotron radiation pink x-ray beam emitted from an in-vacuum hybrid undulator at the SPring-8 facility. The spectrum of the section of the diamond film penetrated by the emitted visible red light exhibited a peak at 739 nm and a wideband structure extending from 550 to 700 nm. The PL intensity increased with the absorbed dose of the incident beam in the diamond within a dynamic range of 10{sup 3}. A two-dimensional distribution of the PL intensity revealed the undulator beam profile.

  11. Signal-to-noise ratio of intensity interferometry experiments with highly asymmetric x-ray sources

    SciTech Connect

    Feng, Y.P.; McNulty, I.; Xu, Z.; Gluskin, E.

    1997-02-11

    We discuss the signal-to-noise ratio of an intensity interferometry experiment for a highly asymmetric x-ray source using different aperture shapes in front of the photodetectors. It is argued that, under ideal conditions using noiseless detectors and electronics, the use of slit-shaped apertures, whose widths are smaller but whose lengths are much greater than the transverse coherence widths of the beam in the corresponding directions, provides no signal-to-noise advantage over the use of pinhole apertures equal to or smaller than the coherence area. As with pinholes, the signal-to-noise ratio is determined solely by the count degeneracy parameter and the degree of coherence of the beam. This contrasts with the signal-to-noise ratio enhancement achievable using slit-shaped apertures with an asymmetric source in a Young`s experiment.

  12. Signal-to-noise ratio of intensity interferometry experiments with highly asymmetric x-ray sources

    SciTech Connect

    Feng, Y.P.; McNulty, I.; Xu, Z.; Gluskin, E.

    1995-06-23

    The authors discuss the signal-to-noise ratio of an intensity interferometry experiment for a highly asymmetric x-ray source using different aperture shapes in front of the photodetectors. It is argued that, under ideal conditions using noiseless detectors and electronics, the use of slit-shaped apertures, whose widths are smaller but whose lengths are much greater than the transverse coherence widths of the beam in the corresponding directions, provides no signal-to-noise advantage over the use of pinhole apertures equal to or smaller than the coherence area. As with pinholes, the signal-to-noise ratio is determined solely by the count degeneracy parameter and the degree of coherence of the beam. This contrasts with the signal-to-noise ratio enhancement achievable using slit-shaped apertures with an asymmetric source in a Young`s experiment.

  13. Silicon Mirrors for High-Intensity X-Ray Pump and Probe Experiments

    NASA Astrophysics Data System (ADS)

    Pardini, Tom; Boutet, Sbastien; Bradley, Joseph; Dppner, Tilo; Fletcher, Luke B.; Gardner, Dennis F.; Hill, Randy M.; Hunter, Mark S.; Krzywinski, Jacek; Messerschmidt, Marc; Pak, Arthur E.; Quirin, Florian; Sokolowski-Tinten, Klaus; Williams, Garth J.; Hau-Riege, Stefan P.

    2014-05-01

    An all-x-ray pump and probe capability is highly desired for the free-electron laser community. A possible implementation involves the use of an x-ray mirror downstream of the sample to backreflect the pump beam onto itself. We expose silicon single crystals, a candidate for this hard-x-ray mirror, to the hard-x-ray beam of the Linac Coherent Light Source (SLAC National Acceleration Laboratory) to assess its suitability. We find that silicon is an appropriate mirror material, but its reflectivity at high x-ray fluences is somewhat unpredictable. We attribute this behavior to x-ray-induced local damage in the mirror, which we have characterized post mortem via microdiffraction, scanning electron microscopy, and Raman spectroscopy. We demonstrate a strategy to reduce local damage by using a structured silicon-based mirror. Preliminary results suggest that the latter yields reproducible Bragg reflectivity at high x-ray fluences, promising a path forward for silicon single crystals as x-ray backreflectors.

  14. Femtosecond electronic response of atoms to ultra-intense x-rays.

    SciTech Connect

    Young, L.; Kanter, E .P.; Li, Y.; March, A.-M.; Pratt, S. T.; Santra, R.; Southworth, S. H.; Rohringer, N.; DiMauro, L. F.; Doumy, G.; Roedig, C. A.; Berrah, N.; Fang, L.; Hoener, M.; Bucksbaum, P. H.; Cryan, J. P .; Ghimire, S.; Glownia, J. M.; Reis, D. A.; Bozek, J. D.; Bostedt, C.; Messerschmidt, M.; Western Michigan Univ.; SLAC National Accelerator Lab.; The Ohio State Univ.; LLNL; Univ. of Chicago

    2010-07-01

    An era of exploring the interactions of high-intensity, hard X-rays with matter has begun with the start-up of a hard-X-ray free-electron laser, the Linac Coherent Light Source (LCLS). Understanding how electrons in matter respond to ultra-intense X-ray radiation is essential for all applications. Here we reveal the nature of the electronic response in a free atom to unprecedented high-intensity, short-wavelength, high-fluence radiation (respectively 10{sup 18} W cm{sup -2}, 1.5-0.6 nm, {approx}10{sup 5} X-ray photons per {angstrom}{sup 2}). At this fluence, the neon target inevitably changes during the course of a single femtosecond-duration X-ray pulse - by sequentially ejecting electrons - to produce fully-stripped neon through absorption of six photons. Rapid photoejection of inner-shell electrons produces 'hollow' atoms and an intensity-induced X-ray transparency. Such transparency, due to the presence of inner-shell vacancies, can be induced in all atomic, molecular and condensed matter systems at high intensity. Quantitative comparison with theory allows us to extract LCLS fluence and pulse duration. Our successful modelling of X-ray/atom interactions using a straightforward rate equation approach augurs favourably for extension to complex systems.

  15. Preliminary Designs for Modifications to the X-Ray Source and Beam Monitor of the Marshall Space Flight Center's X-Ray Calibration Facility

    NASA Technical Reports Server (NTRS)

    Croft, W. L.

    1983-01-01

    Preliminary designs for modifications to the X-ray source and beam monitor of the MSFC X-Ray Calibration Facility to meet requirements for the calibration of the Advanced X-Ray Astrophysics Facility are considered. A rhodium plated copper target and rhodium foil filter are proposed as a source of X-rays of approximately 2.6 keV energy. Bragg scattering of the unpolarized X-ray beam from the present source through an angle of 90 deg by a single crystal placed on the axis of the guide tube is proposed as a source of approximately monoenergetic plane polarized X-rays. A sealed xenon proportional counter with a Beryllium window is proposed as a beam monitor for use between 2.5 and 8 keV to obtain improved detection efficiency.

  16. Transmissive Imaging X-Ray Beam Position Monitors (XBPM) for Protein Crystallography (PX) Beamlines

    SciTech Connect

    Fuchs, Martin R.

    2007-01-19

    We present the development of transmissive imaging X-ray Beam Position Monitors (XBPM) for use in Protein Crystallography (PX) beamlines and beamlines operating at photon energies around and above 10 keV and fluxes of 1010 photons/s or higher. Results from different phosphors, substrates and coating techniques are compared with respect to transmission, layer quality and image resolution. The screen absorption is below 10 % for selected phosphors at photon energies above 10 keV. This enables continuous monitoring of both beam shape and intensity during experimental data collection at a few micron resolution. The screens have been designed for monochromatic beams, with a maximum beam diameter of 2 mm (extendible to 25 mm). The presented approach not only promises a generic solution for use in the automation of PX beamlines, but will also be extendible to other state-of-the-art crystal monochromator beamlines.

  17. The VANILLA sensor as a beam monitoring device for X-ray radiation therapy.

    PubMed

    Velthuis, J J; Hugtenburg, R P; Cussans, D; Perry, M; Hall, C; Stevens, P; Lawrence, H; McKenzie, A

    2014-01-01

    Cancer treatments such as intensity-modulated radiotherapy (IMRT) require increasingly complex methods to verify the accuracy and precision of the treatment delivery. In vivo dosimetry based on measurements made in an electronic portal imaging device (EPID) has been demonstrated. The distorting effect of the patient anatomy on the beam intensity means it is difficult to separate changes in patient anatomy from changes in the beam intensity profile. Alternatively, upstream detectors scatter and attenuate the beam, changing the energy spectrum of the beam, and generate contaminant radiation such as electrons. We used the VANILLA device, a Monolithic Active Pixel Sensor (MAPS), to measure the 2D beam profile of a 6 MV X-ray beam at Bristol Hospital in real-time in an upstream position to the patient without clinically significant disturbance of the beam (0.1% attenuation). MAPSs can be made very thin (~20 ?m) with still a very good signal-to-noise performance. The VANILLA can reconstruct the collimated beam edge with approximately 64 ?m precision. PMID:24215812

  18. A split-beam probe-pump-probe scheme for femtosecond time resolved protein X-ray crystallography.

    PubMed

    van Thor, Jasper J; Madsen, Anders

    2015-01-01

    In order to exploit the femtosecond pulse duration of X-ray Free-Electron Lasers (XFEL) operating in the hard X-ray regime for ultrafast time-resolved protein crystallography experiments, critical parameters that determine the crystallographic signal-to-noise (I/?I) must be addressed. For single-crystal studies under low absorbed dose conditions, it has been shown that the intrinsic pulse intensity stability as well as mode structure and jitter of this structure, significantly affect the crystallographic signal-to-noise. Here, geometrical parameters are theoretically explored for a three-beam scheme: X-ray probe, optical pump, X-ray probe (or "probe-pump-probe") which will allow experimental determination of the photo-induced structure factor amplitude differences, ?F, in a ratiometric manner, thereby internally referencing the intensity noise of the XFEL source. In addition to a non-collinear split-beam geometry which separates un-pumped and pumped diffraction patterns on an area detector, applying an additional convergence angle to both beams by focusing leads to integration over mosaic blocks in the case of well-ordered stationary protein crystals. Ray-tracing X-ray diffraction simulations are performed for an example using photoactive yellow protein crystals in order to explore the geometrical design parameters which would be needed. The specifications for an X-ray split and delay instrument that implements both an offset angle and focused beams are discussed, for implementation of a probe-pump-probe scheme at the European XFEL. We discuss possible extension of single crystal studies to serial femtosecond crystallography, particularly in view of the expected X-ray damage and ablation due to the first probe pulse. PMID:26798786

  19. A split-beam probe-pump-probe scheme for femtosecond time resolved protein X-ray crystallography

    SciTech Connect

    van Thor, Jasper J.; Madsen, Anders

    2015-01-01

    In order to exploit the femtosecond pulse duration of X-ray Free-Electron Lasers (XFEL) operating in the hard X-ray regime for ultrafast time-resolved protein crystallography experiments, critical parameters that determine the crystallographic signal-to-noise (I/σI) must be addressed. For single-crystal studies under low absorbed dose conditions, it has been shown that the intrinsic pulse intensity stability as well as mode structure and jitter of this structure, significantly affect the crystallographic signal-to-noise. Here, geometrical parameters are theoretically explored for a three-beam scheme: X-ray probe, optical pump, X-ray probe (or “probe-pump-probe”) which will allow experimental determination of the photo-induced structure factor amplitude differences, ΔF, in a ratiometric manner, thereby internally referencing the intensity noise of the XFEL source. In addition to a non-collinear split-beam geometry which separates un-pumped and pumped diffraction patterns on an area detector, applying an additional convergence angle to both beams by focusing leads to integration over mosaic blocks in the case of well-ordered stationary protein crystals. Ray-tracing X-ray diffraction simulations are performed for an example using photoactive yellow protein crystals in order to explore the geometrical design parameters which would be needed. The specifications for an X-ray split and delay instrument that implements both an offset angle and focused beams are discussed, for implementation of a probe-pump-probe scheme at the European XFEL. We discuss possible extension of single crystal studies to serial femtosecond crystallography, particularly in view of the expected X-ray damage and ablation due to the first probe pulse.

  20. A split-beam probe-pump-probe scheme for femtosecond time resolved protein X-ray crystallography

    PubMed Central

    van Thor, Jasper J.; Madsen, Anders

    2015-01-01

    In order to exploit the femtosecond pulse duration of X-ray Free-Electron Lasers (XFEL) operating in the hard X-ray regime for ultrafast time-resolved protein crystallography experiments, critical parameters that determine the crystallographic signal-to-noise (I/?I) must be addressed. For single-crystal studies under low absorbed dose conditions, it has been shown that the intrinsic pulse intensity stability as well as mode structure and jitter of this structure, significantly affect the crystallographic signal-to-noise. Here, geometrical parameters are theoretically explored for a three-beam scheme: X-ray probe, optical pump, X-ray probe (or probe-pump-probe) which will allow experimental determination of the photo-induced structure factor amplitude differences, ?F, in a ratiometric manner, thereby internally referencing the intensity noise of the XFEL source. In addition to a non-collinear split-beam geometry which separates un-pumped and pumped diffraction patterns on an area detector, applying an additional convergence angle to both beams by focusing leads to integration over mosaic blocks in the case of well-ordered stationary protein crystals. Ray-tracing X-ray diffraction simulations are performed for an example using photoactive yellow protein crystals in order to explore the geometrical design parameters which would be needed. The specifications for an X-ray split and delay instrument that implements both an offset angle and focused beams are discussed, for implementation of a probe-pump-probe scheme at the European XFEL. We discuss possible extension of single crystal studies to serial femtosecond crystallography, particularly in view of the expected X-ray damage and ablation due to the first probe pulse. PMID:26798786

  1. A split-beam probe-pump-probe scheme for femtosecond time resolved protein X-ray crystallography

    DOE PAGESBeta

    van Thor, Jasper J.; Madsen, Anders

    2015-01-01

    In order to exploit the femtosecond pulse duration of X-ray Free-Electron Lasers (XFEL) operating in the hard X-ray regime for ultrafast time-resolved protein crystallography experiments, critical parameters that determine the crystallographic signal-to-noise (I/σI) must be addressed. For single-crystal studies under low absorbed dose conditions, it has been shown that the intrinsic pulse intensity stability as well as mode structure and jitter of this structure, significantly affect the crystallographic signal-to-noise. Here, geometrical parameters are theoretically explored for a three-beam scheme: X-ray probe, optical pump, X-ray probe (or “probe-pump-probe”) which will allow experimental determination of the photo-induced structure factor amplitude differences, ΔF,more » in a ratiometric manner, thereby internally referencing the intensity noise of the XFEL source. In addition to a non-collinear split-beam geometry which separates un-pumped and pumped diffraction patterns on an area detector, applying an additional convergence angle to both beams by focusing leads to integration over mosaic blocks in the case of well-ordered stationary protein crystals. Ray-tracing X-ray diffraction simulations are performed for an example using photoactive yellow protein crystals in order to explore the geometrical design parameters which would be needed. The specifications for an X-ray split and delay instrument that implements both an offset angle and focused beams are discussed, for implementation of a probe-pump-probe scheme at the European XFEL. We discuss possible extension of single crystal studies to serial femtosecond crystallography, particularly in view of the expected X-ray damage and ablation due to the first probe pulse.« less

  2. Damage to inorganic materials illuminated by focused beam of x-ray free-electron laser radiation

    NASA Astrophysics Data System (ADS)

    Koyama, Takahisa; Yumoto, Hirokatsu; Tono, Kensuke; Togashi, Tadashi; Inubushi, Yuichi; Katayama, Tetsuo; Kim, Jangwoo; Matsuyama, Satoshi; Yabashi, Makina; Yamauchi, Kazuto; Ohashi, Haruhiko

    2015-05-01

    X-ray free-electron lasers (XFELs) that utilize intense and ultra-short pulse X-rays may damage optical elements. We investigated the damage fluence thresholds of optical materials by using an XFEL focusing beam that had a power density sufficient to induce ablation phenomena. The 1 ?m focusing beams with 5.5 keV and/or 10 keV photon energies were produced at the XFEL facility SACLA (SPring-8 Angstrom Compact free electron LAser). Test samples were irradiated with the focusing beams under normal and/or grazing incidence conditions. The samples were uncoated Si, synthetic silica glass (SiO2), and metal (Rh, Pt)-coated substrates, which are often used as X-ray mirror materials.

  3. X-ray photoelectron spectroscopy analysis of organic materials irradiated with gas cluster ion beam

    SciTech Connect

    Nakagiri, Motohiro; Toyoda, Noriaki; Yamada, Isao

    2011-01-07

    Irradiation effect of gas cluster ion beams (GCIB) on organic materials were studied with X-ray photoelectron spectroscopy by comparison to that with Ar-monomer ions. In the case of polyimide, the intensity of both N-C = O and -C-O- bond decreased with 500 eV Ar monomer ion irradiation. On the other hand, there was no significant change in the XPS spectra after Ar-GCIB irradiation. From the size-selected GCIB irradiation study, the damages in polyimide decreased with increasing the cluster size owing to the reduction of energy per atoms.

  4. Flash imaging of fine structures of cellular organelles by contact x-ray microscopy with a high intensity laser plasma x-ray source

    NASA Astrophysics Data System (ADS)

    Kado, Masataka; Ishino, Masahiko; Kishimoto, Maki; Tamotsu, Satoshi; Yasuda, Keiko; Kinjo, Yasuhito; Shinohara, Kunio

    2011-09-01

    X-ray flash imaging by contact microscopy with a highly intense laser-plasma x-ray source was achieved for the observation of wet biological cells. The exposure time to obtain a single x-ray image was about 600 ps as determined by the pulse duration of the driving laser pulse. The x-ray flash imaging makes it possible to capture an x-ray image of living biological cells without any artificial treatment such as staining, fixation, freezing, and so on. The biological cells were cultivated directly on the surface of the silicon nitride membranes, which are used for the x-ray microscope. Before exposing the cells to x-rays they were observed by a conventional fluorescent microscope as reference, since the fluorescent microscopes can visualize specific organelles stained with fluorescent dye. Comparing the x-ray images with the fluorescent images of the exact same cells, each cellular organelle observed in the x-ray images was identified one by one and actin filaments and mitochondria were clearly identified in the x-ray images.

  5. X-ray topography using the forward transmitted beam under multiple-beam diffraction conditions

    NASA Astrophysics Data System (ADS)

    Tsusaka, Y.; Takeda, S.; Takano, H.; Yokoyama, K.; Kagoshima, Y.; Matsui, J.

    2016-02-01

    X-ray topographs are taken for a sapphire wafer with the [0001] surface normal, as an example, by forward transmitted synchrotron x-ray beams combined with two-dimensional electronic arrays in the x-ray detector having a spatial resolution of 1 μm. They exhibit no shape deformation and no position shift of the dislocation lines on the topographs. Since the topography is performed under multiple-beam diffraction conditions, the topographic images of a single diffraction (two-wave approximation condition) or plural diffractions (six-wave approximation condition) can be recorded without large specimen position changes. As usual Lang topographs, it is possible to determine the Burgers vector of each dislocation line. Because of high parallelism of the incoming x-rays and linear sensitivity of the electronic arrays to the incident x-rays, the present technique can be used to visualize individual dislocations in single crystals of the dislocation density as high as 1 × 105 cm-2.

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

    NASA Astrophysics Data System (ADS)

    Rcz, E.; Fldes, I. B.; Ry?, 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 1.5?1017 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 4?m 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.

  7. L X-ray satellite effects on the determination of photon emission intensities of radionuclides.

    PubMed

    Rodrigues, M; Loidl, M

    2016-03-01

    L X-ray satellites are usually not considered during the fitting procedure of L X-ray spectra obtained with semiconductor detectors. Based on a high energy resolution spectrum of X-rays of (241)Am obtained with a metallic magnetic calorimeter, it has been demonstrated that satellites are intense with respect to their parent diagram line. In addition, it has been shown that the presence of satellites involves significant systematic errors on the determined photon intensities when they are ignored in the spectrum processing. PMID:26701657

  8. Novel multi-beam X-ray source for vacuum electronics enabled medical imaging applications

    NASA Astrophysics Data System (ADS)

    Neculaes, V. Bogdan

    2013-10-01

    For almost 100 of years, commercial medical X-ray applications have relied heavily on X-ray tube architectures based on the vacuum electronics design developed by William Coolidge at the beginning of the twentieth century. Typically, the Coolidge design employs one hot tungsten filament as the electron source; the output of the tube is one X-ray beam. This X-ray source architecture is the state of the art in today's commercial medical imaging applications, such as Computed Tomography. Recently, GE Global Research has demonstrated the most dramatic extension of the Coolidge vacuum tube design for Computed Tomography (CT) in almost a century: a multi-beam X-ray source containing thirty two cathodes emitting up to 1000 mA, in a cathode grounded - anode at potential architecture (anode up to 140 kV). This talk will present the challenges of the X-ray multi-beam vacuum source design - space charge electron gun design, beam focusing to compression ratios needed in CT medical imaging applications (image resolution is critically dependent on how well the electron beam is focused in vacuum X-ray tubes), electron emitter choice to fit the aggressive beam current requirements, novel electronics for beam control and focusing, high voltage and vacuum solutions, as well as vacuum chamber design to sustain the considerable G forces typically encountered on a CT gantry (an X-ray vacuum tube typically rotates on the CT gantry at less than 0.5 s per revolution). Consideration will be given to various electron emitter technologies available for this application - tungsten emitters, dispenser cathodes and carbon nano tubes (CNT) - and their tradeoffs. The medical benefits potentially enabled by this unique vacuum multi-beam X-ray source are: X-ray dose reduction, reduction of image artifacts and improved image resolution. This work was funded in part by NIH grant R01EB006837.

  9. Design of parallel dual-energy X-ray beam and its performance for security radiography

    NASA Astrophysics Data System (ADS)

    Hyun Kim, Kwang; Min Myoung, Sung; Hyun Chung, Yong

    2011-10-01

    A new concept of dual-energy X-ray beam generation and acquisition of dual-energy security radiography is proposed. Erbium (Er) and rhodium (Rh) with a copper filter were positioned in front of X-ray tube to generate low- and high-energy X-ray spectra. Low- and high-energy X-rays were guided to separately enter into two parallel detectors. Monte Carlo code of MCNPX was used to derive an optimum thickness of each filter for improved dual X-ray image quality. It was desired to provide separation ability between organic and inorganic matters for the condition of 140 kVp/0.8 mA as used in the security application. Acquired dual-energy X-ray beams were evaluated by the dual-energy Z-map yielding enhanced performance compared with a commercial dual-energy detector. A collimator for the parallel dual-energy X-ray beam was designed to minimize X-ray beam interference between low- and high-energy parallel beams for 500 mm source-to-detector distance.

  10. Quasitransient regimes of backward Raman amplification of intense x-ray pulses

    SciTech Connect

    Malkin, V. M.; Fisch, N. J.

    2009-10-15

    New powerful soft x-ray sources may be able to access intensities needed for backward Raman amplification (BRA) of x-ray pulses in plasmas. However, high plasma densities, needed to provide enough coupling between the pump and seed x-ray pulses, cause strong damping of the Langmuir wave that mediates energy transfer from the pump to the seed pulse. Such damping could reduce the coupling, thus making efficient BRA impossible. This work shows that efficient BRA can survive despite the Langmuir wave damping significantly exceeding the linear BRA growth rate. Moreover, the strong Langmuir wave damping can automatically suppress deleterious instabilities of BRA to the thermal noise. The class of 'quasitransient' BRA regimes identified here shows that it may be feasible to observe x-ray BRA within available x-ray facilities.

  11. Quasitransient regimes of backward Raman amplification of intense x-ray pulses

    NASA Astrophysics Data System (ADS)

    Malkin, V. M.; Fisch, N. J.

    2009-10-01

    New powerful soft x-ray sources may be able to access intensities needed for backward Raman amplification (BRA) of x-ray pulses in plasmas. However, high plasma densities, needed to provide enough coupling between the pump and seed x-ray pulses, cause strong damping of the Langmuir wave that mediates energy transfer from the pump to the seed pulse. Such damping could reduce the coupling, thus making efficient BRA impossible. This work shows that efficient BRA can survive despite the Langmuir wave damping significantly exceeding the linear BRA growth rate. Moreover, the strong Langmuir wave damping can automatically suppress deleterious instabilities of BRA to the thermal noise. The class of quasitransient BRA regimes identified here shows that it may be feasible to observe x-ray BRA within available x-ray facilities.

  12. Calibration of X-ray Imaging Devices for Accurate Intensity Measurement

    SciTech Connect

    Haugh, M. J., Charest, M., Ross, P., Lee, J. Schneider, M., Palmer, N., Teruya,

    2012-06-01

    National Security Technologies (NSTec) has developed calibration procedures for X-ray imaging systems using NIST traceable sources. The X-ray sources that are used for calibration are both diode type and diode/fluorescer combinations. Calibrating the X-ray detectors is the key to accurate calibration of the X-ray sources. Both energy dispersive detectors and photodiodes measuring total flux were used. We have developed calibration techniques for the detectors using radioactive sources that are traceable to the National Institute of Standards and Technology (NIST). The German synchrotron at Physikalische Technische Bundestalt (PTB) is used to calibrate silicon photodiodes over the energy range from 50 eV to 60 keV. The measurements on X-ray cameras made using the NSTec X-ray sources have included the quantum efficiency averaged over all pixels, the camera counts per photon per pixel, and response variation across the sensor. The instrumentation required to accomplish the calibrations is described. X-ray energies ranged from 720 eV to 22.7 keV. The X-ray sources produce narrow energy bands, allowing us to determine the properties as a function of X-ray energy. The calibrations were done for several types of imaging devices. There were back illuminated and front illuminated CCD (charge coupled device) sensors, and a CID (charge injection device) type camera. The CCD and CID camera types differ significantly in some of their properties that affect the accuracy of X-ray intensity measurements. All cameras discussed here are silicon based. The measurements of quantum efficiency variation with X-ray energy are compared to models for the sensor structure. Cameras that are not back-thinned are compared to those that are.

  13. CALIBRATION OF X-RAY IMAGING DEVICES FOR ACCURATE INTENSITY MEASUREMENT

    SciTech Connect

    Haugh, M J; Charest, M R; Ross, P W; Lee, J J; Schneider, M B; Palmer, N E; Teruya, A T

    2012-02-16

    National Security Technologies (NSTec) has developed calibration procedures for X-ray imaging systems. The X-ray sources that are used for calibration are both diode type and diode/fluorescer combinations. Calibrating the X-ray detectors is key to accurate calibration of the X-ray sources. Both energy dispersive detectors and photodiodes measuring total flux were used. We have developed calibration techniques for the detectors using radioactive sources that are traceable to the National Institute of Standards and Technology (NIST). The German synchrotron at Physikalische Technische Bundestalt (PTB) is used to calibrate silicon photodiodes over the energy range from 50 eV to 60 keV. The measurements on X-ray cameras made using the NSTec X-ray sources have included quantum efficiency averaged over all pixels, camera counts per photon per pixel, and response variation across the sensor. The instrumentation required to accomplish the calibrations is described. X-ray energies ranged from 720 eV to 22.7 keV. The X-ray sources produce narrow energy bands, allowing us to determine the properties as a function of X-ray energy. The calibrations were done for several types of imaging devices. There were back illuminated and front illuminated CCD (charge coupled device) sensors, and a CID (charge injection device) type camera. The CCD and CID camera types differ significantly in some of their properties that affect the accuracy of X-ray intensity measurements. All cameras discussed here are silicon based. The measurements of quantum efficiency variation with X-ray energy are compared to models for the sensor structure. Cameras that are not back-thinned are compared to those that are.

  14. Intense quasi-monochromatic flash x-ray generator utilizing molybdenum-target diode

    NASA Astrophysics Data System (ADS)

    Sagae, Michiaki; Sato, Eiichi; Obara, Haruo; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Sato, Shigehiro; Ojima, Hidenori; Takayama, Kazuyoshi; Ido, Hideaki

    2005-03-01

    In the flash x-ray generator, a 150 nF condenser is charged up to 80 kV by a power supply, and flash x rays are produced by the discharging. The x-ray tube is a demountable diode, and the turbomolecular pump evacuates air from the tube with a pressure of approximately 1 mPa. Since the electric circuit of the high-voltage pulse generator employs a cable transmission line, the high-voltage pulse generator produces twice the potential of the condenser charging voltage. At a charging voltage of 80 kV, the estimated maximum tube voltage and current were approximately 160 kV and 40 kA, respectively. When the charging voltage was increased, the K-series characteristic x-ray intensities of molybdenum increased. The K lines were clean and intense, and hardly any bremsstrahlung rays were detected at all. The x-ray pulse widths were approximately 100 ns, and the time-integrated x-ray intensity had a value of approximately 15 ?C/kg at 1.0 m from the x-ray source with a charging voltage of 80 kV.

  15. In situ micro-focused X-ray beam characterization with a lensless camera using a hybrid pixel detector.

    PubMed

    Kachatkou, Anton; Marchal, Julien; van Silfhout, Roelof

    2014-03-01

    Results of studies on micro-focused X-ray beam diagnostics using an X-ray beam imaging (XBI) instrument based on the idea of recording radiation scattered from a thin foil of a low-Z material with a lensless camera are reported. The XBI instrument captures magnified images of the scattering region within the foil as illuminated by the incident beam. These images contain information about beam size, beam position and beam intensity that is extracted during dedicated signal processing steps. In this work the use of the device with beams for which the beam size is significantly smaller than that of a single detector pixel is explored. The performance of the XBI device equipped with a state-of-the-art hybrid pixel X-ray imaging sensor is analysed. Compared with traditional methods such as slit edge or wire scanners, the XBI micro-focused beam characterization is significantly faster and does not interfere with on-going experiments. The challenges associated with measuring micrometre-sized beams are described and ways of optimizing the resolution of beam position and size measurements of the XBI instrument are discussed. PMID:24562554

  16. The effect of exit beam phase aberrations on parallel beam coherent x-ray reconstructions.

    SciTech Connect

    Hruszkewycz, S. O.; Harder, R.; Xiao, X.; Fuoss, P. H.

    2010-12-01

    Diffraction artifacts from imperfect x-ray windows near the sample are an important consideration in the design of coherent x-ray diffraction measurements. In this study, we used simulated and experimental diffraction patterns in two and three dimensions to explore the effect of phase imperfections in a beryllium window (such as a void or inclusion) on the convergence behavior of phasing algorithms and on the ultimate reconstruction. A predictive relationship between beam wavelength, sample size, and window position was derived to explain the dependence of reconstruction quality on beryllium defect size. Defects corresponding to this prediction cause the most damage to the sample exit wave and induce signature error oscillations during phasing that can be used as a fingerprint of experimental x-ray window artifacts. The relationship between x-ray window imperfection size and coherent x-ray diffractive imaging reconstruction quality explored in this work can play an important role in designing high-resolution in situ coherent imaging instrumentation and will help interpret the phasing behavior of coherent diffraction measured in these in situ environments.

  17. The effect of exit beam phase aberrations on parallel beam coherent x-ray reconstructions

    SciTech Connect

    Hruszkewycz, S. O.; Fuoss, P. H.; Harder, R.; Xiao, X.

    2010-12-15

    Diffraction artifacts from imperfect x-ray windows near the sample are an important consideration in the design of coherent x-ray diffraction measurements. In this study, we used simulated and experimental diffraction patterns in two and three dimensions to explore the effect of phase imperfections in a beryllium window (such as a void or inclusion) on the convergence behavior of phasing algorithms and on the ultimate reconstruction. A predictive relationship between beam wavelength, sample size, and window position was derived to explain the dependence of reconstruction quality on beryllium defect size. Defects corresponding to this prediction cause the most damage to the sample exit wave and induce signature error oscillations during phasing that can be used as a fingerprint of experimental x-ray window artifacts. The relationship between x-ray window imperfection size and coherent x-ray diffractive imaging reconstruction quality explored in this work can play an important role in designing high-resolution in situ coherent imaging instrumentation and will help interpret the phasing behavior of coherent diffraction measured in these in situ environments.

  18. An investigation on some of the tumor treatment cases using x-rays and electron beams

    NASA Astrophysics Data System (ADS)

    Ucar, Burcu; Yigitoglu, Ibrahim; Arslan Kabalay, Ipek; Altiparmak, Duygu; Kilicaslan, Sinem

    2015-07-01

    In this work, we discussed some of the applications which X-rays and electron beam used in radiotherapy for tumor treatments. This study has been performed at Radiation Oncology Department, Medicine Faculty in Gaziosmanpasa University by using the VARIAN CLINICA DHX linear accelerator which is operated in the range of 6 MeV - 15 MeV. Processes for the treatments that X-rays used for pancreas, bladder and prostate tumors and the processes that the electron beam used for some of the derm tumors are studied. Effects of X-rays and electron beams to treatments process are examined and the obtained results are presented comparatively.

  19. Modulation of hard x-ray beam profiles by Borrmann pyramid

    SciTech Connect

    Xu, G.; Britten, J.

    2008-01-15

    Spatial modulation of hard x-ray beam profiles is reported, using the 'Borrmann pyramid' formed in dual Bragg diffraction of a single crystal, where a small angular change of the incident beam is magnified to span the entire pyramid base. As an attempt, it is demonstrated using hard x rays by (1) the linear shift of a micrometer sized mask; (2) the partial blockade of a two micron beam; and (3) the millimeter shadow of a nanoscale gold strip, which shows the potential application of Borrmann pyramids in the form of an enlarged x-ray image.

  20. Efficient electronic structure calculation for molecular ionization dynamics at high x-ray intensity

    PubMed Central

    Hao, Yajiang; Inhester, Ludger; Hanasaki, Kota; Son, Sang-Kil; Santra, Robin

    2015-01-01

    We present the implementation of an electronic-structure approach dedicated to ionization dynamics of molecules interacting with x-ray free-electron laser (XFEL) pulses. In our scheme, molecular orbitals for molecular core-hole states are represented by linear combination of numerical atomic orbitals that are solutions of corresponding atomic core-hole states. We demonstrate that our scheme efficiently calculates all possible multiple-hole configurations of molecules formed during XFEL pulses. The present method is suitable to investigate x-ray multiphoton multiple ionization dynamics and accompanying nuclear dynamics, providing essential information on the chemical dynamics relevant for high-intensity x-ray imaging. PMID:26798806

  1. Possibility Of Enlarging X-Ray Exposure Area With X-Ray Mirror Or By Electron Beam Vertical Motion

    NASA Astrophysics Data System (ADS)

    Betz, H.; Mulhaupt, G.

    1984-03-01

    High collimation of synchrotron radiation perpendicular to the orbital plane of the 'electrons in a storage ring results in only a small exposed stripe on the wafer. Typically, the height ranges between 0.5 and 1 cm. Two methods of enlarging the exposure field, dealt with in this paper, are the application of plane scanning X-ray mirrors and the stimulation of electron beam oscillations in the ring. Due to the considerable decrease in reflectivity with decreasing wavelength and increasing mirror angle, the usable reflection angles are limited to the grazing-incidence region below 2° in the case of X-ray lithography. The pure Si02-mirror (Zerodur) used in the experiments has reflectivities above 80 % at up to 1.5°. For the wavelengths in question (--1 nm). The theoretical values of the absorbed energy in the resist, depending on the glacing angle, have been compared with experimental results. From this dependence, the velocity profile of the mirror movement for attaining a homogeneous exposure can be derived. The preliminary experiments concerning surface degradation due to cracked hydrocarbons indicate that this factor is not as severe as previously expected in the case of the soft X-rays used in lithography. The alternative method of enlarging the exposed area, by stimulating electron oscillations in the storage ring, has also been investigated. The initial results show a practically-homogeneous exposure area 3 cm in height. A simple improvement in the control electronics for the additional steering magnets, which is being made at the moment, will at least double this area. Then, the exposable step-and-repeat field will amount to 6 x 6 cm2 with this specific method, which does not require any special arrangements in the beam line.

  2. 77 FR 12226 - Sadex Corp.; Filing of Food Additive Petition (Animal Use); Electron Beam and X-Ray Sources for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-29

    ... Petition (Animal Use); Electron Beam and X-Ray Sources for Irradiation of Poultry Feed and Poultry Feed... regulations be amended to provide for the safe use of electron beam and x-ray sources for irradiation of... use of electron beam and x- ray sources for irradiation of poultry feed and poultry feed...

  3. X-ray lithography source

    DOEpatents

    Piestrup, M.A.; Boyers, D.G.; Pincus, C.

    1991-12-31

    A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits is disclosed. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and eliminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an excellent moderate-priced X-ray source for lithography. 26 figures.

  4. X-ray lithography source

    DOEpatents

    Piestrup, Melvin A. (Woodside, CA); Boyers, David G. (Mountain View, CA); Pincus, Cary (Sunnyvale, CA)

    1991-01-01

    A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and elminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an exellent moderate-priced X-ray source for lithography.

  5. ANALYSIS AND MITIGATION OF X-RAY HAZARD GENERATED FROM HIGH INTENSITY LASER-TARGET INTERACTIONS

    SciTech Connect

    Qiu, R.; Liu, J.C.; Prinz, A.A.; Rokni, S.H.; Woods, M.; Xia, Z.; ,

    2011-03-21

    Interaction of a high intensity laser with matter may generate an ionizing radiation hazard. Very limited studies have been made, however, on the laser-induced radiation protection issue. This work reviews available literature on the physics and characteristics of laser-induced X-ray hazards. Important aspects include the laser-to-electron energy conversion efficiency, electron angular distribution, electron energy spectrum and effective temperature, and bremsstrahlung production of X-rays in the target. The possible X-ray dose rates for several femtosecond Ti:sapphire laser systems used at SLAC, including the short pulse laser system for the Matter in Extreme Conditions Instrument (peak power 4 TW and peak intensity 2.4 x 10{sup 18} W/cm{sup 2}) were analysed. A graded approach to mitigate the laser-induced X-ray hazard with a combination of engineered and administrative controls is also proposed.

  6. On the resolution and linearity of lensless in situ X-ray beam diagnostics using pixelated sensors.

    PubMed

    Kachatkou, Anton; van Silfhout, Roelof

    2013-02-25

    We present a theoretical model that describes the resolution and linearity of a novel transparent X-ray beam imaging and position measurement method. Using a pinhole or coded aperture camera with pixelated area sensors to image a small fraction of radiation scattered by a thin foil placed at oblique angles with respect to the beam, a very precise measurement of the beam position is made. We show that the resolution of the method is determined by incident beam intensity, beam size, camera parameters, sensor pixel size and noise. The model is verified experimentally showing a sub-micrometer resolution over a large linear range. PMID:23481962

  7. Calculated X-ray Intensities Using Monte Carlo Algorithms: A Comparison to Experimental EPMA Data

    NASA Technical Reports Server (NTRS)

    Carpenter, P. K.

    2005-01-01

    Monte Carlo (MC) modeling has been used extensively to simulate electron scattering and x-ray emission from complex geometries. Here are presented comparisons between MC results and experimental electron-probe microanalysis (EPMA) measurements as well as phi(rhoz) correction algorithms. Experimental EPMA measurements made on NIST SRM 481 (AgAu) and 482 (CuAu) alloys, at a range of accelerating potential and instrument take-off angles, represent a formal microanalysis data set that has been widely used to develop phi(rhoz) correction algorithms. X-ray intensity data produced by MC simulations represents an independent test of both experimental and phi(rhoz) correction algorithms. The alpha-factor method has previously been used to evaluate systematic errors in the analysis of semiconductor and silicate minerals, and is used here to compare the accuracy of experimental and MC-calculated x-ray data. X-ray intensities calculated by MC are used to generate a-factors using the certificated compositions in the CuAu binary relative to pure Cu and Au standards. MC simulations are obtained using the NIST, WinCasino, and WinXray algorithms; derived x-ray intensities have a built-in atomic number correction, and are further corrected for absorption and characteristic fluorescence using the PAP phi(rhoz) correction algorithm. The Penelope code additionally simulates both characteristic and continuum x-ray fluorescence and thus requires no further correction for use in calculating alpha-factors.

  8. Two (and more) sharp X-ray wavelengths in one beam

    NASA Astrophysics Data System (ADS)

    Hrd, J.; Hrd, J.; Oberta, P.; Pacherov, O.

    2016-01-01

    It is proposed how to create and merge two parallel X-ray beams with different wavelengths. The proposed method is based on simultaneous diffraction on two or more different crystallographic planes of perfect single crystals. Possible applications are discussed.

  9. 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.

  10. Diamond X-ray beam-position monitoring using signal readout at the synchrotron radiofrequency.

    PubMed

    Morse, J; Solar, B; Graafsma, H

    2010-07-01

    Single-crystal diamond is a material with great potential for the fabrication of X-ray photon beam-position monitors with submicrometre spatial resolution. Low X-ray absorption combined with radiation hardness and excellent thermal-mechanical properties make possible beam-transmissive diamond devices for monitoring synchrotron and free-electron laser X-ray beams. Tests were made using a white bending-magnet synchrotron X-ray beam at DESY to investigate the performance of a position-sensitive diamond device using radiofrequency readout electronics. The device uniformity and position response were measured in a 25 microm collimated X-ray beam with an I-Tech Libera ;Brilliance' system. This readout system was designed for position measurement and feedback control of the electron beam in the synchrotron storage ring, but, as shown here, it can also be used for accurate position readout of a quadrant-electrode single-crystal diamond sensor. The centre-of-gravity position of the F4 X-ray beam at the DORIS III synchrotron was measured with the diamond signal output digitally sampled at a rate of 130 Msample s(-1) by the Brilliance system. Narrow-band filtering and digital averaging of the position signals resulted in a measured position noise below 50 nm (r.m.s.) for a 10 Hz bandwidth. PMID:20567077

  11. Diffraction of a focused X-ray beam by surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Tucoulou, R.; Schelokov, I. A.; Roschchupkin, D. V.; Brunel, M.; Ortega, L.; Chevallier, P.

    1995-02-01

    This paper reports the first attempt to carry out a focusing followed by a space-time scanning of a synchrotron X-ray beam. The focusing is performed through an elliptical multilayer Bragg-Fresnel lens while the space-time scanning is due to the grazing incidence diffraction on the YZ-cut of a LiNbO 3 crystal modulated by pulsed surface acoustic waves. It opens the field of a new generation of X-ray beam control devices which should be of interest for X-ray scanning microscopy or time resolved spectroscopy. These experiments were carried out at LURE (Orsay, France).

  12. X ray constraints on the beaming hypothesis for BL Lacertae objects

    NASA Technical Reports Server (NTRS)

    Padovani, P.; Urry, C. M.

    1989-01-01

    BL Lacertae objects may be Fanaroff-Riley type I (FR I) galaxies with a relativistic jet roughly parallel to the line of sight. The ratio of parent objects (FR Is) to beamed objects (BL Lacs) depends only on the jet velocity. Recently this ratio become observable. X-ray-flux-limited samples are used to demonstrate the viability of the beaming hypothesis. In the process, the X-ray luminosity functions of FR I galaxies and BL Lac objects are derived. Their respective contributions to the cosmic X-ray background radiation are calculated.

  13. Lensless Diffractive Imaging Using Tabletop Coherent High-Harmonic Soft-X-Ray Beams

    SciTech Connect

    Sandberg, Richard L.; Paul, Ariel; Raymondson, Daisy A.; Haedrich, Steffen; Gaudiosi, David M.; Holtsnider, Jim; Tobey, Ra'anan I.; Cohen, Oren; Murnane, Margaret M.; Kapteyn, Henry C.; Song, Changyong; Miao Jianwei; Liu Yanwei; Salmassi, Farhad

    2007-08-31

    We present the first experimental demonstration of lensless diffractive imaging using coherent soft x rays generated by a tabletop soft-x-ray source. A 29 nm high harmonic beam illuminates an object, and the subsequent diffraction is collected on an x-ray CCD camera. High dynamic range diffraction patterns are obtained by taking multiple exposures while blocking small-angle diffraction using beam blocks of varying size. These patterns reconstruct to images with 214 nm resolution. This work demonstrates a practical tabletop lensless microscope that promises to find applications in materials science, nanoscience, and biology.

  14. Determination of multiwavelength anomalous diffraction coefficients at high x-ray intensity

    NASA Astrophysics Data System (ADS)

    Son, Sang-Kil; Chapman, Henry N.; Santra, Robin

    2013-08-01

    The high-intensity version of multiwavelength anomalous diffraction (MAD) has a potential for solving the phase problem in femtosecond crystallography with x-ray free-electron lasers (XFELs). For MAD phasing, it is required to calculate or measure the MAD coefficients involved in the key equation, which depend on XFEL pulse parameters. In this work, we revisit the generalized Karle-Hendrickson equation to clarify the importance of configurational fluctuations of heavy atoms induced by intense x-ray pulses, and investigate the high-intensity cases of transmission and fluorescence measurements of samples containing heavy atoms. Based on transmission/fluorescence and diffraction experiments with crystalline samples of known structures, we propose an experimental procedure to determine all MAD coefficients at high x-ray intensity, which can be used in ab initio phasing for unknown structures.

  15. Impact of hollow-atom formation on coherent x-ray scattering at high intensity

    SciTech Connect

    Son, Sang-Kil; Young, Linda; Santra, Robin

    2011-03-15

    X-ray free-electron lasers (FELs) are promising tools for structural determination of macromolecules via coherent x-ray scattering. During ultrashort and ultraintense x-ray pulses with an atomic-scale wavelength, samples are subject to radiation damage and possibly become highly ionized, which may influence the quality of x-ray scattering patterns. We develop a toolkit to treat detailed ionization, relaxation, and scattering dynamics for an atom within a consistent theoretical framework. The coherent x-ray scattering problem including radiation damage is investigated as a function of x-ray FEL parameters such as pulse length, fluence, and photon energy. We find that the x-ray scattering intensity saturates at a fluence of {approx}10{sup 7} photon/A{sup 2} per pulse but can be maximized by using a pulse duration much shorter than the time scales involved in the relaxation of the inner-shell vacancy states created. Under these conditions, both inner-shell electrons in a carbon atom are removed, and the resulting hollow atom gives rise to a scattering pattern with little loss of quality for a spatial resolution >1 A. Our numerical results predict that in order to scatter from a carbon atom 0.1 photon per x-ray pulse, within a spatial resolution of 1.7 A, a fluence of 1x10{sup 7} photons/A{sup 2} per pulse is required at a pulse length of 1 fs and a photon energy of 12 keV. By using a pulse length of a few hundred attoseconds, one can suppress even secondary ionization processes in extended systems. The present results suggest that high-brightness attosecond x-ray FELs would be ideal for single-shot imaging of individual macromolecules.

  16. Spectrum bandwidth narrowing of Thomson scattering X-rays with energy chirped electron beams from laser wakefield acceleration

    SciTech Connect

    Xu, Tong; Chen, Min Li, Fei-Yu; Yu, Lu-Le; Sheng, Zheng-Ming; SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG ; Zhang, Jie; Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190

    2014-01-06

    We study incoherent Thomson scattering between an ultrashort laser pulse and an electron beam accelerated from a laser wakefield. The energy chirp effects of the accelerated electron beam on the final radiation spectrum bandwidth are investigated. It is found that the scattered X-ray radiation has the minimum spectrum width and highest intensity as electrons are accelerated up to around the dephasing point. Furthermore, it is proposed that the electron acceleration process inside the wakefield can be studied by use of 90° Thomson scattering. The dephasing position and beam energy chirp can be deduced from the intensity and bandwidth of the scattered radiation.

  17. Soft X-Ray Emission and Charged Particles Beams from a Plasma Focus of Hundreds Joules

    SciTech Connect

    Silva, Patricio; Moreno, Jose; Soto, Leopoldo; Pavez, Cristian; Arancibia, Jaime

    2006-12-04

    In a new stage of characterization of our plasma focus devices of hundred and tens of joules (PF-400J and PF-50J), preliminary series of measurements on soft X-ray and ion beams have been performed in the device PF-400J (176-539 J, 880 nF, T/4 {approx}300 ns). The device was operated in hydrogen to 7 mbar of pressure . The temporal and spatial X-ray characteristics are investigated by means filtered PIN diodes and a multipinhole camera. Graphite collectors, operating in the bias ion collector mode, are used to estimate the characteristic ion energy using the time flight across the probe array. The time of the ion beam emission to be correlated with plasma emission events associated with the soft X-ray pulses detected by the probes. Temporal correlations between soft X-ray signals and ion beams are performed.

  18. An X-ray scattering beam line at the national synchrotron light source

    NASA Astrophysics Data System (ADS)

    Kvick, .; Koetzle, T. F.; Hastings, J. B.; Thomlinson, W.

    An X-ray beam line for chemical crystallography and scattering research is under construction at the National Synchrotron Light Source (Brookhaven National Laboratory). The X-ray beam is designed to be tunable in the energy region 4 to 21 keV ( ? = 0.6-3.1 ) with an energy resolution ( ?E/ E) of 5 10 -4. The intensity will be uniform to better than 1% over an area of 0.3 10.3 mm 2 at the sample position. The beam optics will consist of two mirrors: one spherical and one bent cylinder approximating an ellipsoid, as well as a fixed exit double-crystal (Si) monochromator. The line will be instrumental with a four-circle goniostat (Huber) designed to work in both vertical and horizontal modes. The chi-circle has an inner diameter of 40 cm and an offset phi-axis to allow the use of a variety of sample chambers such as high- or low-temperature devices. The diffractometer will be controlled by a PDP-11/23 microcomputer operating under RSX-11M. The beam line initially will be outfitted with a single-channel detector. Equipment will also include a rotation camera for extensive data collections on macromolecules using film as a detection medium. The beam line is designed and built jointly by a Participating Research Team and the National Synchrotron Light Source Facility and is expected to commence regular experimental research, after an initial start-up period, during the first half of 1982.

  19. Pseudopotential calculations of photoionization of atoms in the x-ray photon energy range and FEL beam monitor development

    NASA Astrophysics Data System (ADS)

    Chernov, V. E.; Dorofeev, D. L.; Elfimov, S. V.; Zon, B. A.; Gavrilov, G. E.; Naryshkin, Yu G.

    2015-03-01

    A pseudopotential model for calculation of atomic processes under interaction with hard x-ray photons is applied to calculation of Krypton photoionization cross sections by photons with energy in the 20-25 keV range. These cross sections, as well as the mean charge of the resulting ions calculated using the Monte Carlo simulation scheme, are in good agreement with the other theoretical calculations and with the experiment. The obtained results open the doors for new techniques in the design of gas-monitor detectors to control the intensity, coordinates and energy of x-ray free-electron laser (XFEL) beams in the hard x-ray photon energy range. First, Monte Carlo simulations of a scintillation detector application for gas-monitors have been performed.

  20. Performance Characteristics Of An Intensity Modulated Advanced X-Ray Source (IMAXS) For Homeland Security Applications

    SciTech Connect

    Langeveld, Willem G. J.; Brown, Craig; Condron, Cathie; Ingle, Mike; Christensen, Phil A.; Johnson, William A.; Owen, Roger D.; Ross, Randy

    2011-06-01

    X-ray cargo inspection systems for the detection and verification of threats and contraband must address stringent, competitive performance requirements. High x-ray intensity is needed to penetrate dense cargo, while low intensity is desirable to minimize the radiation footprint, i.e. the size of the controlled area, required shielding and the dose to personnel. In a collaborative effort between HESCO/PTSE Inc., XScell Corp., Stangenes Industries, Inc. and Rapiscan Laboratories, Inc., an Intensity Modulated Advanced X-ray Source (IMAXS) was designed and produced. Cargo inspection systems utilizing such a source have been projected to achieve up to 2 inches steel-equivalent greater penetration capability, while on average producing the same or smaller radiation footprint as present fixed-intensity sources. Alternatively, the design can be used to obtain the same penetration capability as with conventional sources, but reducing the radiation footprint by about a factor of three. The key idea is to anticipate the needed intensity for each x-ray pulse by evaluating signal strength in the cargo inspection system detector array for the previous pulse. The IMAXS is therefore capable of changing intensity from one pulse to the next by an electronic signal provided by electronics inside the cargo inspection system detector array, which determine the required source intensity for the next pulse. We report on the completion of a 9 MV S-band (2998 MHz) IMAXS source and comment on its performance.

  1. X-ray intensity patterns from finite perfect crystals.

    PubMed

    Thorkildsen; Larsen

    1999-11-01

    A theoretical study dealing with intensity interference patterns from the exit surfaces of finite perfect t x l crystals has been undertaken using the Takagi-Taupin equations and the Riemann-Green technique. Nu-meri-cal simulations have been performed for the 220 reflection in diamond allowing for different types of amplitude-modulated incoming plane waves. The effects caused by limiting the waves by a slit system are also discussed. The results show strong influence of the lateral crystal boundaries and are closely related to the geometrical region structures formed by the characteristic lines associated with the equations. In the limit of a semi-infinite crystal, the Borrmann-Lehmann interference patterns are retrieved. PMID:10927317

  2. Surface profiling of X-ray mirrors for shaping focused beams.

    PubMed

    Laundy, David; Alianelli, Lucia; Sutter, John; Evans, Gwyndaf; Sawhney, Kawal

    2015-01-26

    Grazing incidence mirrors are a standard optic for focusing X-rays. Active mirrors, whose surface profile can be finely adjusted, allow control of beam shape and size at the sample. However, progress towards their routine use for beam shaping has been hampered by the strong striations in reflected beams away from the focal plane. Re-entrant (partly concave and partly convex) surface modifications are proposed for shaping X-ray beams to a top-hat in the focal plane while reducing the striations caused by unavoidable polishing errors. A method for constructing such surfaces with continuous height and slope (but only piecewise continuous curvature) will be provided. Ray tracing and wave propagation calculations confirm its effectiveness. A mirror system is proposed allowing vertical beam sizes in the range 0.5 to 10?m. A prototype will be fabricated and is expected to have applications on many synchrotron X-ray beamlines. PMID:25835915

  3. Application of focused-beam flat-sample method to synchrotron powder X-ray diffraction with anomalous scattering effect

    NASA Astrophysics Data System (ADS)

    Tanaka, M.; Katsuya, Y.; Matsushita, Y.

    2013-03-01

    The focused-beam flat-sample method (FFM), which is a method for high-resolution and rapid synchrotron X-ray powder diffraction measurements by combination of beam focusing optics, a flat shape sample and an area detector, was applied for diffraction experiments with anomalous scattering effect. The advantages of FFM for anomalous diffraction were absorption correction without approximation, rapid data collection by an area detector and good signal-to-noise ratio data by focusing optics. In the X-ray diffraction experiments of CoFe2O4 and Fe3O4 (By FFM) using X-rays near the Fe K absorption edge, the anomalous scattering effect between Fe/Co or Fe2+/Fe3+ can be clearly detected, due to the change of diffraction intensity. The change of observed diffraction intensity as the incident X-ray energy was consistent with the calculation. The FFM is expected to be a method for anomalous powder diffraction.

  4. A method for implementing the diffraction of a widely divergent X-ray beam

    SciTech Connect

    Avetyan, K. T.; Arakelyan, M. M.

    2008-11-15

    A method for implementing the diffraction of a widely divergent characteristic X-ray beam from a standard X-ray tube with a linear focal spot was improved. X rays, passing through a diaphragm 30 {mu}m in diameter, diffract from a crystal adjacent to the diaphragm. The crystal, together with a photographic plate, rotates around the axis perpendicular to the plate. It is shown that the diffraction image is a set of hyperbolas in this case. The equations of the hyperbolas are obtained and investigated. A method for interpreting the diffraction images in the case of small crystal asymmetry is proposed.

  5. Method for beam hardening correction in quantitative computed X-ray tomography

    NASA Technical Reports Server (NTRS)

    Yan, Chye Hwang (Inventor); Whalen, Robert T. (Inventor); Napel, Sandy (Inventor)

    2001-01-01

    Each voxel is assumed to contain exactly two distinct materials, with the volume fraction of each material being iteratively calculated. According to the method, the spectrum of the X-ray beam must be known, and the attenuation spectra of the materials in the object must be known, and be monotonically decreasing with increasing X-ray photon energy. Then, a volume fraction is estimated for the voxel, and the spectrum is iteratively calculated.

  6. High Gain, Fast Scan, Broad Spectrum, Parallel Beam Wavelength Dispersive X-ray Spectrometer for SEM

    SciTech Connect

    David OHara; Dr. Eric Lochmer

    2003-09-12

    Parallax Research, Inc. proposes to produce a new type of x-ray spectrometer for use with Scanning Electron Microscopy (SEM) that would have the energy resolution of WDS and the ease of use of EDS with sufficient gain for lower energies that it can be used at low beam currents as is EDS. Parallax proposes to do this by development of new multiple reflection x-ray collimation optics, new diffractor technology, new detector technology and new scan algorithms.

  7. X-ray laser

    DOEpatents

    Nilsen, Joseph (Livermore, CA)

    1991-01-01

    An X-ray laser (10) that lases between the K edges of carbon and oxygen, i.e. between 44 and 23 Angstroms, is provided. The laser comprises a silicon (12) and dysprosium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like dysprosium ions (34) are resonantly photo-pumped to their upper X-ray laser state by line emission from hydrogen-like silicon ions (32). The novel X-ray laser should prove especially useful for the microscopy of biological specimens.

  8. Transverse Coherence of the LCLS X-Ray Beam

    SciTech Connect

    Not Available

    2010-12-01

    Self-amplifying spontaneous radiation free-electron lasers, such as the LCLS or the European X-FEL, rely on the incoherent, spontaneous radiation as the seed for the amplifying process. Though this method overcomes the need for an external seed source one drawback is the incoherence of the effective seed signal. The FEL process allows for a natural growth of the coherence because the radiation phase information is spread out within the bunch due to slippage and diffraction of the radiation field. However, at short wavelengths this spreading is not sufficient to achieve complete coherence. In this presentation we report on the results of numerical simulations of the LCLS X-ray FEL. From the obtained radiation field distribution the coherence properties are extracted to help to characterize the FEL as a light source.

  9. Transverse Coherence Properties of the LCLS X-Ray Beam

    SciTech Connect

    Reiche, S.; /UCLA

    2007-04-16

    Self-amplifying spontaneous radiation free-electron lasers, such as the LCLS or the European X-FEL, rely on the incoherent, spontaneous radiation as the seed for the amplifying process. Though this method overcomes the need for an external seed source one drawback is the incoherence of the effective seed signal. The FEL process allows for a natural growth of the coherence because the radiation phase information is spread out within the bunch due to slippage and diffraction of the radiation field. However, at short wavelengths this spreading is not sufficient to achieve complete coherence. In this presentation we report on the results of numerical simulations of the LCLS X-ray FEL. From the obtained radiation field distribution the coherence properties are extracted to help to characterize the FEL as a light source.

  10. X-ray enhancement in a nanohole target irradiated by intense ultrashort laser pulses

    SciTech Connect

    Chakravarty, U.; Arora, V.; Chakera, J. A.; Naik, P. A.; Srivastava, H.; Tiwari, P.; Srivastava, A.; Gupta, P. D

    2011-03-01

    In this paper, we present a comparative study of the laser energy absorption, soft x-ray emission (in the water window region: 2.3-4.4 nm) and hard x-ray emission (in the 2-20 keV range) from planar aluminum and nanohole alumina of 40 nm average diameter, when irradiated by Ti:sapphire laser pulses. The laser pulse duration was varied from 45 to 500 fs, and the focused intensity on the target ranged from {approx}3 x 10{sup 16} W/cm{sup 2} to 3x10{sup 17} W/cm{sup 2}. The x-ray yield enhancement from the nanoholes shows an increased coupling of the laser energy to the target. The effect of laser pulse duration on the x-ray emission was also studied, where a resonance like phenomenon was observed. The laser energy absorption measurements in the nanoholes showed a marginal enhancement in absorption as compared to planar Al. The integrated keV x-ray yield, from nanohole alumina and planar Al, at an intensity of 3 x 10{sup 17} W/cm{sup 2}, was 25 and 3.5 {mu}J, respectively. The results can be explained by considering the hydrodynamic expansion of the laser irradiated structure and field enhancement in the nanoholes.

  11. Modeling Relativistic Electron Precipitation Bremsstrahlung X-Ray Intensities at 10-100 km Manned Vehicle Altitudes

    NASA Technical Reports Server (NTRS)

    Krause, L. Habsh; Gilchrist, B. E.; Nishikawa, Ken-Ichi

    2013-01-01

    Relativisitic electron precipitation (REP) events occur when beams or bunches of relativistic electrons of magnetospheric origin enter the Earth's atmosphere, typically at auroral latitudes. REP events are associated with a variety of space weather effects, including production of transitional and bremsstrahlung radiation, catalytic depletion of stratospheric ozone, and scintillation of transionospheric radio waves. This study examines the intensities of x-rays produced at airliner, manned balloon, and space reuseable launch vehicles (sRLVs). The monoenergetic beam is modeled in cylindrical symetry using the paraxial ray equation. Bremsstrahlung photon production is calculated using the traditional Sauter-Elwert cross-section, providing x-ray emission spectra differential in energy and angle. Attenuation is computed for a plane-stratified standard atmosphere, and the loss processes include photoionization, Rayleigh and Compton scattering, electron-positron pair production, and photonuclear interaction. Peak altitudes of electron energy deposition and bremsstrahlung x-ray production were calculated for beams of energies from 1 MeV through 100 MeV. The altitude peak of bremsstrahlung deposition was consistently and significantly lower that that of the electron deposition due to the longer mean free paths of x-rays compared to electrons within the atmosphere. For example, for a nadir-directed monoenergetic 5 MeV beam, the peak deposition altitude was calculated to be 42 km, but the resulting bremsstrahlung deposition peaked at 25 km. This has implications for crew and passenger safety, especially with the growth of the space tourism industry. A survey of results covering the 1-100 MeV spectrum for the three altitude ranges of interest will be presented.

  12. Modeling Relativistic Electron Precipitation Bremsstrahlung X-Ray Intensities at 10-100 km Manned Vehicle Altitudes

    NASA Astrophysics Data System (ADS)

    Habash Krause, L.; Gilchrist, B. E.; Nishikawa, K.; Williams, A.

    2013-12-01

    Relativistic electron precipitation (REP) events occur when beams or bunches of relativistic electrons of magnetospheric origin enter the Earth's atmosphere, typically at auroral latitudes. REP events are associated with a variety of space weather effects, including production of transitional and bremsstrahlung radiation, catalytic depletion of stratospheric ozone, and scintillation of transionospheric radio waves. This study examines the intensities of x-rays produced at airliner, manned balloon, and suborbital Reusable Launch Vehicle (sRLV) altitudes. The monoenergetic beam is modeled in cylindrical symmetry using the paraxial ray equation. Bremsstrahlung photon production is calculated using the traditional Sauter-Elwert cross-section, providing x-ray emission spectra differential in energy and angle. Attenuation is computed for a plane-stratified standard atmosphere, and the loss processes include photoionization, Rayleigh and Compton scattering, electron-positron pair production, and photonuclear interaction. Peak altitudes of electron energy deposition and bremsstrahlung x-ray production were calculated for beams of energies from 1 MeV through 100 MeV. The altitude peak of bremsstrahlung deposition was consistently and significantly lower that that of the electron deposition due to the longer mean free paths of x-rays compared to electrons within the atmosphere. For example, for a nadir-directed monoenergetic 5 MeV beam, the peak deposition altitude was calculated to be 42 km, but the resulting bremmstrahlung deposition peaked at 25 km. This has implications for crew and passenger safety, especially with the growth of the space tourism industry that relies on sRLVs with a nominal apogee of 100 km. A survey of results covering the 1-100 MeV spectrum for the three altitude ranges of interest will be presented.

  13. Photoionized argon plasmas induced with intense soft x-ray and extreme ultraviolet pulses

    NASA Astrophysics Data System (ADS)

    Bartnik, A.; Wachulak, P.; Fok, T.; Węgrzyński, Ł.; Fiedorowicz, H.; Skrzeczanowski, W.; Pisarczyk, T.; Chodukowski, T.; Kalinowska, Z.; Dudzak, R.; Dostal, J.; Krousky, E.; Skala, J.; Ullschmied, J.; Hrebicek, J.; Medrik, T.

    2016-01-01

    In this work, photoionized plasmas were created by irradiation of gaseous argon with soft x-ray (SXR) and extreme ultraviolet (EUV) intense radiation pulses. Two different laser-produced plasma sources, employing a low energy Nd:YAG laser and a high energy iodine laser system (PALS), were used for creation of photoionized plasmas. In both cases the EUV or SXR beam irradiated the Ar stream, injected into a vacuum chamber synchronously with the radiation pulse. Emission spectra, measured for the Ar photoionized plasmas indicated strong differences in ionization degree for plasmas produced using low and high energy systems. In case of the the EUV driving pulses, emission lines corresponding to neutral atoms and singly charged ions were observed. In case of the SXR pulses utilized for the photoionized plasma creation, only Ar V–VIII emission lines were recorded. Additionally, electron density measurements were performed by laser interferometry employing a femtosecond laser system synchronized with the irradiating system. Maximum electron density for the Ar photoionized plasma, induced using the high energy system, reached 1.9 · 1018 cm‑3. Interferometric measurements performed for the moment of maximum intensity of the main laser pulse (t  =  0) revealed no fringe shift. Detection limit for the interferometric measurements was estimated. It allowed to estimate the upper limit for electron density at t  =  0 as 5 · 1016 cm‑3.

  14. Superficial dosimetry imaging based on ?erenkov emission for external beam radiotherapy with megavoltage x-ray beam

    PubMed Central

    Zhang, Rongxiao; Glaser, Adam K.; Gladstone, David J.; Fox, Colleen J.; Pogue, Brian W.

    2013-01-01

    Purpose: ?erenkov radiation emission occurs in all tissue, when charged particles (either primary or secondary) travel at velocity above the threshold for the ?erenkov effect (about 220 KeV in tissue for electrons). This study presents the first examination of optical ?erenkov emission as a surrogate for the absorbed superficial dose for MV x-ray beams. Methods: In this study, Monte Carlo simulations of flat and curved surfaces were studied to analyze the energy spectra of charged particles produced in different regions near the surfaces when irradiated by MV x-ray beams. ?erenkov emission intensity and radiation dose were directly simulated in voxelized flat and cylindrical phantoms. The sampling region of superficial dosimetry based on ?erenkov radiation was simulated in layered skin models. Angular distributions of optical emission from the surfaces were investigated. Tissue mimicking phantoms with flat and curved surfaces were imaged with a time domain gating system. The beam field sizes (50 50200 200 mm2), incident angles (070) and imaging regions were all varied. Results: The entrance or exit region of the tissue has nearly homogeneous energy spectra across the beam, such that their ?erenkov emission is proportional to dose. Directly simulated local intensity of ?erenkov and radiation dose in voxelized flat and cylindrical phantoms further validate that this signal is proportional to radiation dose with absolute average discrepancy within 2%, and the largest within 5% typically at the beam edges. The effective sampling depth could be tuned from near 0 up to 6 mm by spectral filtering. The angular profiles near the theoretical Lambertian emission distribution for a perfect diffusive medium, suggesting that angular correction of ?erenkov images may not be required even for curved surface. The acquisition speed and signal to noise ratio of the time domain gating system were investigated for different acquisition procedures, and the results show there is good potential for real-time superficial dose monitoring. Dose imaging under normal ambient room lighting was validated, using gated detection and a breast phantom. Conclusions: This study indicates that ?erenkov emission imaging might provide a valuable way to superficial dosimetry imaging in real time for external beam radiotherapy with megavoltage x-ray beams. PMID:24089916

  15. Superficial dosimetry imaging based on Čerenkov emission for external beam radiotherapy with megavoltage x-ray beam

    SciTech Connect

    Zhang, Rongxiao; Glaser, Adam K.; Gladstone, David J.; Fox, Colleen J.; Pogue, Brian W.; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766; Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755

    2013-10-15

    Purpose: Čerenkov radiation emission occurs in all tissue, when charged particles (either primary or secondary) travel at velocity above the threshold for the Čerenkov effect (about 220 KeV in tissue for electrons). This study presents the first examination of optical Čerenkov emission as a surrogate for the absorbed superficial dose for MV x-ray beams.Methods: In this study, Monte Carlo simulations of flat and curved surfaces were studied to analyze the energy spectra of charged particles produced in different regions near the surfaces when irradiated by MV x-ray beams. Čerenkov emission intensity and radiation dose were directly simulated in voxelized flat and cylindrical phantoms. The sampling region of superficial dosimetry based on Čerenkov radiation was simulated in layered skin models. Angular distributions of optical emission from the surfaces were investigated. Tissue mimicking phantoms with flat and curved surfaces were imaged with a time domain gating system. The beam field sizes (50 × 50–200 × 200 mm{sup 2}), incident angles (0°–70°) and imaging regions were all varied.Results: The entrance or exit region of the tissue has nearly homogeneous energy spectra across the beam, such that their Čerenkov emission is proportional to dose. Directly simulated local intensity of Čerenkov and radiation dose in voxelized flat and cylindrical phantoms further validate that this signal is proportional to radiation dose with absolute average discrepancy within 2%, and the largest within 5% typically at the beam edges. The effective sampling depth could be tuned from near 0 up to 6 mm by spectral filtering. The angular profiles near the theoretical Lambertian emission distribution for a perfect diffusive medium, suggesting that angular correction of Čerenkov images may not be required even for curved surface. The acquisition speed and signal to noise ratio of the time domain gating system were investigated for different acquisition procedures, and the results show there is good potential for real-time superficial dose monitoring. Dose imaging under normal ambient room lighting was validated, using gated detection and a breast phantom.Conclusions: This study indicates that Čerenkov emission imaging might provide a valuable way to superficial dosimetry imaging in real time for external beam radiotherapy with megavoltage x-ray beams.

  16. Fast X-Ray Transients and Gamma-Ray Bursts: Constraints on Beaming

    NASA Astrophysics Data System (ADS)

    Grindlay, Jonathan E.

    1999-01-01

    The detection of X-ray afterglows of ?-ray burst (GRB) sources has enabled the optical discovery that GRBs are at cosmological distances, which confirms that the enormous luminosities required must produce a relativistically expanding fireball. It is not yet clear whether this expansion is quasi-spherical or beamed, or if the beaming differs between the prompt GRB and afterglow, although the differences for both source emission and population models are profound. We show that relative beaming (prompt vs. afterglow) may be constrained by analysis of the ``fast transient'' X-ray sources cataloged by Pye & McHardy from the Ariel 5 survey as well as several other surveys (e.g., HEAO 1 experiments A-1/A-2). After removing contamination from likely stellar transients, and scaling from X-ray/?-ray fluence ratios recently derived from Ginga and BeppoSAX, approximately half of the sources were possible prompt emission or afterglows from GRBs with ?-ray fluence of >~1.2 10-5 ergs cm-2. Since the rate of these candidate afterglow events, 0.15 day-1, is consistent with the BATSE log N-log S distribution, no difference in prompt versus afterglow beaming is required. However, more sensitive X-ray monitors or hard X-ray imaging surveys, with better temporal and spatial resolution, could provide strong constraints on GRBs and beaming.

  17. Quasitransient regimes of backward Raman amplification of intense x-ray pulses

    NASA Astrophysics Data System (ADS)

    Malkin, Vladimir; Fisch, Nathaniel

    2008-11-01

    The backward Raman amplification (BRA) of laser pulses is considered under conditions when important features of the transient BRA survive, while BRA is noticeably affected by damping of the Langmuir wave mediating energy transfer from the pump to the pumped pulse. These quasitransient BRA regimes appear to be relevant to possible principle-of-proof experiments on BRA of intense x-ray laser pulses in plasmas. In particular, such experiments found to be feasible within the parameter range of currently built powerful soft x-ray sources.

  18. The Location of the Most Intense Unidentified X-Ray Source on the Celestial Sphere

    NASA Astrophysics Data System (ADS)

    Margon, Bruce

    1999-09-01

    We propose to use the unprecedented X-ray spatial resolution and aspect determination accuracy of AXAF to obtain the optical/IR identification of what may be the most intense but as yet unidentified steady X-ray source on the celestial sphere, GX17+2 (=X1813-140). Although this object is a prototype of the important Z-sources (which include Sco X-1 and Cyg X-2), evidence is now very strong that the long-accepted optical identification is incorrect. We have recently obtained HST NICMOS observations of the field which point the way towards reopening this perplexing problem of 25 years duration. The proposed observations will simultaneously provide a high-quality X-ray spectrum.

  19. Effect of X-ray beam quality on determination of exposure index.

    PubMed

    Yasumatsu, Shogo; Tanaka, Nobukazu; Iwase, Kensuke; Shimizu, Yoichiro; Morishita, Junji

    2016-01-01

    We investigated the effect of X-ray beam qualities RQA3, 5, 7, and 9 on the exposure index (EI) as defined by International Electrotechnical Commission guideline 62494-1. Half-value layers (HVLs) of RQA5 X-rays passing through anti-scatter grids (grid ratios 6:1, 8:1, 10:1, and 12:1) were also evaluated because grids are frequently used in clinical situations. The maximum percent differences in the EIs for RQA3, 7, and 9 with respect to RQA5 were 35.0, 11.6, and 38.7 %, respectively. The range of HVLs for RQA5-7 beams was 7.10-9.10 mm of aluminum (mm Al). This was wider than the range of HVLs when grids were used (6.94-7.29 mm Al). The effect of variations in X-ray beam qualities in the RQA series on the EI was significantly greater than the effect of grids. This study indicated that, in clinical settings, the EI should be used carefully in X-ray examinations with different X-ray beam qualities. PMID:26619973

  20. Application of a transmission crystal x-ray spectrometer to moderate-intensity laser driven sources

    NASA Astrophysics Data System (ADS)

    Mao, J. Y.; Chen, L. M.; Hudson, L. T.; Seely, J. F.; Zhang, L.; Sun, Y. Q.; Lin, X. X.; Zhang, J.

    2012-04-01

    In the pursuit of novel, laser-produced x-ray sources for medical imaging applications, appropriate instrumental diagnostics need to be developed concurrently. A type of transmission crystal spectroscopy has previously been demonstrated as a survey tool for sources produced by high-power and high-energy lasers. The present work demonstrates the extension of this method into the study of medium-intensity laser driven hard x-ray sources with a design that preserves resolving power while maintaining high sensitivity. Specifically, spectroscopic measurements of characteristic K? and K? emissions were studied from Mo targets irradiated by a 100 fs, 200 mJ, Ti: sapphire laser with intensity of 1017 W/cm2 to 1018 W/cm2 per shot. Using a transmission curved crystal spectrometer and off-Rowland circle imaging, resolving powers (E/?E) of around 300 for Mo K?2 at 17.37 keV were obtained with an end-to-end spectrometer efficiency of (1.13 0.10) 10-5. This sensitivity is sufficient for registering x-ray lines with high signal to background from targets following irradiation by a single laser pulse, demonstrating the utility of this method in the study of the development of medium-intensity laser driven x-ray sources.

  1. Microcontrolled pyro-electric instrument for measuring X-ray intensity in mammography.

    PubMed

    de Paula, M H; de Carvalho, A A; Brassalotti, A L; Alter, A J; Sakamoto, W K; Malmonge, J A; de Almeida, A

    2005-11-01

    A novel instrument for measurement of X-ray intensity from mammography consists of a sensitive pyro-electric detector, a high-sensitivity, low-noise current-to-voltage converter, a microcontroller and a digital display. The heart of this device, and what makes it unique is the pyro-electric detector, which measures radiation by converting heat from absorbed incident X-rays into an electric current. This current is then converted to a voltage and digitised. The detector consists of a ferro-electric crystal; two types were tested: lithium tantalate and lithium niobate. X-ray measurement in mammography is challenging because of its relatively low photon energy range, from 11 keV to 15 keV equivalent mean energy, corresponding to a peak tube potential from 22 to 36 kV. Consequently, energy fluence rate or intensity is low compared with that of common diagnostic X-ray. The instrument is capable of measuring intensities as low as 0.25 mW m(-2) with precision greater than 99%. Not only was the instrument capable of performing in the clinical environment, with high background electromagnetic interference and vibration, but its performance was not degraded after being subjected to 140 roentgen (3.6 x 10(-2) C kg(-2) air) as measured by piezo-electric (d33) or pyro-electric coefficients. PMID:16594302

  2. Fragmentation of clusters and recombination induced by intense and ultrashort x-ray laser pulses

    NASA Astrophysics Data System (ADS)

    Timneanu, N.; Iwan, B.; Andreasson, J.; Bergh, M.; Seibert, M.; Bostedt, C.; Schorb, S.; Thomas, H.; Rupp, D.; Gorkhover, T.; Adolph, M.; Mller, T.; Helal, A.; Hoffmann, K.; Kandadai, N.; Keto, J.; Ditmire, T.

    2013-05-01

    Understanding the ultrafast dynamics of matter under extreme conditions is relevant for structural studies and plasma physics with X-ray lasers. We used the pulses from free-electron lasers (FLASH in Hamburg and LCLS in Stanford) to trigger X-ray induced explosions in atomic atoms (Xe) and molecular clusters (CH4 and CD4). The explosion dynamics depends on cluster size and the intensity of the X-ray pulse, and a transition from Coulomb explosion to hydrodynamic expansion is expected with increasing size and increasing pulse intensity. In methane clusters experiments at FLASH, the time-of-flight spectrometry shows the appearance of molecular adducts which are the result of molecular recombination between ions and molecules. The recombination depends on the cluster size and the expansion mechanism and becomes significant in larger clusters. In Xenon cluster experiments at the LCLS, measurements of the ion charge states in clusters suggest a formation of Xe nanoplasma which expands hydrodynamically. The dominance of low charge states of Xe is due to three-body recombination processes involving electron and Xe ions, and it depends on the X-ray intensity and nanoplasma formation.

  3. Application of a transmission crystal x-ray spectrometer to moderate-intensity laser driven sources

    SciTech Connect

    Mao, J. Y.; Chen, L. M.; Zhang, L.; Sun, Y. Q.; Lin, X. X.; Hudson, L. T.; Seely, J. F.; Zhang, J.

    2012-04-15

    In the pursuit of novel, laser-produced x-ray sources for medical imaging applications, appropriate instrumental diagnostics need to be developed concurrently. A type of transmission crystal spectroscopy has previously been demonstrated as a survey tool for sources produced by high-power and high-energy lasers. The present work demonstrates the extension of this method into the study of medium-intensity laser driven hard x-ray sources with a design that preserves resolving power while maintaining high sensitivity. Specifically, spectroscopic measurements of characteristic K{alpha} and K{beta} emissions were studied from Mo targets irradiated by a 100 fs, 200 mJ, Ti: sapphire laser with intensity of 10{sup 17} W/cm{sup 2} to 10{sup 18} W/cm{sup 2} per shot. Using a transmission curved crystal spectrometer and off-Rowland circle imaging, resolving powers (E/{Delta}E) of around 300 for Mo K{alpha}{sub 2} at 17.37 keV were obtained with an end-to-end spectrometer efficiency of (1.13 {+-} 0.10) x 10{sup -5}. This sensitivity is sufficient for registering x-ray lines with high signal to background from targets following irradiation by a single laser pulse, demonstrating the utility of this method in the study of the development of medium-intensity laser driven x-ray sources.

  4. Application of a transmission crystal x-ray spectrometer to moderate-intensity laser driven sources.

    PubMed

    Mao, J Y; Chen, L M; Hudson, L T; Seely, J F; Zhang, L; Sun, Y Q; Lin, X X; Zhang, J

    2012-04-01

    In the pursuit of novel, laser-produced x-ray sources for medical imaging applications, appropriate instrumental diagnostics need to be developed concurrently. A type of transmission crystal spectroscopy has previously been demonstrated as a survey tool for sources produced by high-power and high-energy lasers. The present work demonstrates the extension of this method into the study of medium-intensity laser driven hard x-ray sources with a design that preserves resolving power while maintaining high sensitivity. Specifically, spectroscopic measurements of characteristic K? and K? emissions were studied from Mo targets irradiated by a 100 fs, 200 mJ, Ti: sapphire laser with intensity of 10(17) W/cm(2) to 10(18) W?cm(2) per shot. Using a transmission curved crystal spectrometer and off-Rowland circle imaging, resolving powers (E/?E) of around 300 for Mo K?(2) at 17.37 keV were obtained with an end-to-end spectrometer efficiency of (1.13 0.10) 10(-5). This sensitivity is sufficient for registering x-ray lines with high signal to background from targets following irradiation by a single laser pulse, demonstrating the utility of this method in the study of the development of medium-intensity laser driven x-ray sources. PMID:22559512

  5. Design and Implementation of an Acoustic X-ray Detector to Measure the LCLS Beam Energy

    SciTech Connect

    Loos, Jennifer L.; /San Jose State U. /SLAC

    2010-08-25

    On April 11, 2009, first light was seen from LCLS. The present apparatus being used to measure the x-ray beam energy is the Total Energy Sensor which uses a suite of thermal sensors. Another device is needed to cross-check the energy measurements. This new diagnostic tool utilizes radiation acoustic phenomena to determine the x-ray beam energy. A target is hit by the x-rays from the beam, and a voltage is generated in two piezoelectric sensors attached to the target in response to the consequent deformation. Once the voltage is known, the power can be obtained. Thermal sensors will also be attached to the target for calibration purposes. Material selection and design were based on: durability, ultra-high vacuum compatibility, safety and thermal properties. The target material was also chosen for its acoustic properties which were determined from tests using a frequency generator and laser. Initial tests suggest the device will function as anticipated.

  6. Fast X-ray Transients and Gamma-ray Bursts: Constraints on Beaming

    NASA Astrophysics Data System (ADS)

    Grindlay, Jonathan E.

    1998-04-01

    The detection of x-ray afterglows of gamma-ray burst (GRB) sources has allowed the optical discovery that GRBs are at cosmological distances so that the enormous luminosities required must produce a relativistically expanding fireball. It is not yet clear if this expansion is quasi-spherical or beamed, although the differences for both source emission and population models are profound. We show that x-ray afterglows may constrain beaming by analysis of the ``fast transient" x-ray sources catalogued by Pye and McHardy (1983) from the Ariel V survey. Many or most of these 2-10 keV sources were probably GRB afterglows, implying limits on the corresponding total GRB rate. Comparison with the GRB rate measured by BATSE at 50-300 keV then allows constraints on both beaming and afterglow emission models to be derived.

  7. Time-delayed beam splitting with energy separation of x-ray channels

    SciTech Connect

    Stetsko, Yuri P.; Shvyd'ko, Yuri V.; Brian Stephenson, G.

    2013-10-21

    We introduce a time-delayed beam splitting method based on the energy separation of x-ray photon beams. It is implemented and theoretically substantiated on an example of an x-ray optical scheme similar to that of the classical Michelson interferometer. The splitter/mixer uses Bragg-case diffraction from a thin diamond crystal. Another two diamond crystals are used as back-reflectors. Because of energy separation and a minimal number (three) of optical elements, the split-delay line has high efficiency and is simple to operate. Due to the high transparency of diamond crystal, the split-delay line can be used in a beam sharing mode at x-ray free-electron laser facilities.

  8. X-ray beam-shaping via deformable mirrors: Analytical computation of the required mirror profile

    NASA Astrophysics Data System (ADS)

    Spiga, Daniele; Raimondi, Lorenzo; Svetina, Cristian; Zangrando, Marco

    2013-05-01

    X-ray mirrors with high focusing performances are in use in both mirror modules for X-ray telescopes and in synchrotron and FEL (Free Electron Laser) beamlines. A degradation of the focus sharpness arises in general from geometrical deformations and surface roughness, the former usually described by geometrical optics and the latter by physical optics. In general, technological developments are aimed at a very tight focusing, which requires the mirror profile to comply with the nominal shape as much as possible and to keep the roughness at a negligible level. However, a deliberate deformation of the mirror can be made to endow the focus with a desired size and distribution, via piezo actuators as done at the EIS-TIMEX beamline of FERMI@Elettra. The resulting profile can be characterized with a Long Trace Profilometer and correlated with the expected optical quality via a wavefront propagation code. However, if the roughness contribution can be neglected, the computation can be performed via a ray-tracing routine, and, under opportune assumptions, the focal spot profile (the Point Spread Function, PSF) can even be predicted analytically. The advantage of this approach is that the analytical relation can be reversed; i.e., from the desired PSF the required mirror profile can be computed easily, thereby avoiding the use of complex and time-consuming numerical codes. The method can also be suited in the case of spatially inhomogeneous beam intensities, as commonly experienced at synchrotrons and FELs. In this work we expose the analytical method and the application to the beam shaping problem.

  9. X-ray Radiation and Electron Injection from Beam Envelope Oscillations in Plasma Wakefield Accelerator Experiments at FACET

    NASA Astrophysics Data System (ADS)

    Marsh, K. A.; An, W.; Clayton, C. E.; Joshi, C.; Lu, W.; Mori, W. B.; Vafaei-Najafabadi, N.; Clarke, C.; Corde, S.; Delahaye, J. P.; England, J.; Fisher, A.; Frederico, J.; Gessner, S.; Hogan, M. J.; Li, S.; Litos, M.; Walz, D.; Wu, Z.; Adli, E.

    2013-10-01

    PWFA experiments at FACET at the SLAC National Accelerator Laboratory have shown a correlation between ionization-injected electrons and the betatron x-ray yield. The PWFA experiments were carried out using a rubidium vapor heat pipe oven. The vapor density was 2.5 1017 cm-3 and was ionized by the 20 GeV electron beam via tunneling ionization. The injected charge and x-ray yield are attributed to the beam envelope oscillations where at the oscillation minima, the field of the beam is strong enough to ionize RbII, and at the electron oscillation maxima, the beam electrons radiate x-rays. In general the x-ray yield scales as r2n2?2 , but for a matched beam the x-ray yield is reduced and scales as r3/2n3/2 ? . The FACET x-ray diagnostic can be used to tune the drive beam parameters for matched propagation by minimizing the x-ray yield. For a matched beam, there is no beam envelope oscillation, thus the x-ray yield and unwanted beam loading are greatly reduced. Injection of plasma electrons into the wake can limit the wake amplitude and deplete the accelerating gradient. Minimizing the x-ray yield should reduce unwanted beam loading. UCLA supported by: DE-FG02-92-ER40727 and PHY-0936266. SLAC supported by DE-AC02-76SF00515.

  10. Delivery confirmation of bolus electron conformal therapy combined with intensity modulated x-ray therapy

    SciTech Connect

    Kavanaugh, James A.; Hogstrom, Kenneth R.; Fontenot, Jonas P.; Henkelmann, Gregory; Chu, Connel; Carver, Robert A.

    2013-02-15

    Purpose: The purpose of this study was to demonstrate that a bolus electron conformal therapy (ECT) dose plan and a mixed beam plan, composed of an intensity modulated x-ray therapy (IMXT) dose plan optimized on top of the bolus ECT plan, can be accurately delivered. Methods: Calculated dose distributions were compared with measured dose distributions for parotid and chest wall (CW) bolus ECT and mixed beam plans, each simulated in a cylindrical polystyrene phantom that allowed film dose measurements. Bolus ECT plans were created for both parotid and CW PTVs (planning target volumes) using 20 and 16 MeV beams, respectively, whose 90% dose surface conformed to the PTV. Mixed beam plans consisted of an IMXT dose plan optimized on top of the bolus ECT dose plan. The bolus ECT, IMXT, and mixed beam dose distributions were measured using radiographic films in five transverse and one sagittal planes for a total of 36 measurement conditions. Corrections for film dose response, effects of edge-on photon irradiation, and effects of irregular phantom optical properties on the Cerenkov component of the film signal resulted in high precision measurements. Data set consistency was verified by agreement of depth dose at the intersections of the sagittal plane with the five measured transverse planes. For these same depth doses, results for the mixed beam plan agreed with the sum of the individual depth doses for the bolus ECT and IMXT plans. The six mean measured planar dose distributions were compared with those calculated by the treatment planning system for all modalities. Dose agreement was assessed using the 4% dose difference and 0.2 cm distance to agreement. Results: For the combined high-dose region and low-dose region, pass rates for the parotid and CW plans were 98.7% and 96.2%, respectively, for the bolus ECT plans and 97.9% and 97.4%, respectively, for the mixed beam plans. For the high-dose gradient region, pass rates for the parotid and CW plans were 93.1% and 94.62%, respectively, for the bolus ECT plans and 89.2% and 95.1%, respectively, for the mixed beam plans. For all regions, pass rates for the parotid and CW plans were 98.8% and 97.3%, respectively, for the bolus ECT plans and 97.5% and 95.9%, respectively, for the mixed beam plans. For the IMXT component of the mixed beam plans, pass rates for the parotid and CW plans were 93.7% and 95.8%. Conclusions: Bolus ECT and mixed beam therapy dose delivery to the phantom were more accurate than IMXT delivery, adding confidence to the use of planning, fabrication, and delivery for bolus ECT tools either alone or as part of mixed beam therapy. The methodology reported in this work could serve as a basis for future standardization of the commissioning of bolus ECT or mixed beam therapy. When applying this technology to patients, it is recommended that an electron dose algorithm more accurate than the pencil beam algorithm, e.g., a Monte Carlo algorithm or analytical transport such as the pencil beam redefinition algorithm, be used for planning to ensure the desired accuracy.

  11. Observation of the Talbot effect using broadband hard x-ray beam

    SciTech Connect

    Kim, J.M.; Conley, R.; Cho, I. H.; Lee, S. Y.; Kang, H. C.; Liu, C.; Macrander, A. T.; Noh, D. Y.

    2010-11-15

    We demonstrated the Talbot effect using a broadband hard x-ray beam ({Delta}{lambda}/{lambda} {approx}1). The exit wave-field of the x-ray beam passing through a grating with a sub micro-meter scale period was successfully replicated and recorded at effective Talbot distance, Z{sub T}. The period was reduced to half at Z{sub T}/4 and 3/4Z{sub T}, and the phase reversal was observed at Z{sub T}/2. The propagating wave-field recorded on photoresists was consistent with a simulated result.

  12. Monte Carlo model of the scanning beam digital x-ray (SBDX) source

    PubMed Central

    Bazalova, M; Weil, MD; Wilfley, B; Graves, EE

    2014-01-01

    The scanning-beam digital x-ray (SBDX) system has been developed for fluoroscopic imaging using an inverse x-ray imaging geometry. The SBDX system consists of a large-area x-ray source with a multihole collimator and a small detector. The goal of this study was to build a Monte Carlo (MC) model of the SBDX source as a useful tool for optimization of the SBDX imaging system in terms of its hardware components and imaging parameters. The MC model of the source was built in the EGSnrc/BEAMnrc code and validated using the DOSXYZnrc code and Gafchromic film measurements for 80, 100, and 120 kV x-ray source voltages. The MC simulated depth dose curves agreed with measurements to within 5%, and beam profiles at three selected depths generally agreed within 5%. Exposure rates and half-value layers for three voltages were also calculated from the MC simulations. Patient skin-dose per unit detector-dose was quantified as a function of patient size for all three x-ray source voltages. The skin-dose to detector-dose ratio ranged from 510 for a 20 cm thick patient to 1 1031 105 for a 50 cm patient for the 120 and 80 kV beams, respectively. Simulations of imaging dose for a prostate patient using common imaging parameters revealed that skin-dose per frame was as low as 0.2 mGy. PMID:23093305

  13. Characteristics of secondary electrons produced by 6, 10 and 24 MV x-ray beams

    NASA Astrophysics Data System (ADS)

    Jursinic, Paul A.; Mackie, T. Rock

    1996-08-01

    Megavoltage x-ray beams generated by linear accelerators (linacs) deliver their maximum dose a few centimetres below the treatment or phantom surface. This skin-sparing effect is degraded by the generation of secondary electrons as the x-ray beam passes to the patient or phantom. This work measures the characteristics of these electrons. A light-weight electromagnet was constructed that could be mounted in the block-tray position, 58 cm from the x-ray source of a Varian Clinac 2100C or 2500 linac. A field strength as high as 0.1500 T was generated, which was strong enough to sweep secondary electrons out of a field. For 6, 10 and 24 MV x-ray beams, secondary contamination electrons produced 18, 38 and 65% of the surface dose, corresponding to 3, 5 and 12% of the maximum dose, respectively. A parameterized depth - dose curve for the contamination electrons was produced and was valid for all the x-ray energies studied.

  14. A study of monochromatic x-ray area beam for application in diffraction enhanced imaging

    NASA Astrophysics Data System (ADS)

    Kim, Chang Hyeuk

    Synchrotron-based Diffraction Enhanced Imaging (DEI) system has shown improved contrast images on low attenuation material. In a previous DEI study great potential to detect earlier stage breast cancer was reported. However, to apply DEI technique at the clinical level, a synchrotron source is not feasible for clinically-approved systems due to the size of the accelerator, and hence a compact x-ray source that can replace synchrotron is desirable. Development of an x-ray source compatible to synchrotron radiation is an essential part for a clinical DEI system. Some important features for the design of an x-ray source, based on synchrotron radiation, are the photon flux and beam collimation. The NCSU research group suggested a wide-beam x-ray source, which consists of concentric circular filaments producing electron flux onto a cylindrically-shaped oxygen-free copper stationary target with a thin layer of Molybdenum for x-ray production. This source design emphasizes large field of view, which can eliminate the line by line scanning process experienced in a DEI experimental setup. In this study, the proof of principle model of a wide beam x-ray source was used to study for control electron trajectory of the concentric filaments design, calculations of the produced x-ray flux, simulation of the DEI imaging, and estimation of the operation time with target's active cooling system. The DEI images from the electron distribution were computationally generated by adopting a monochromator and an analyzer with a computationally generated dual cylindrical object. The image simulation showed that the wide-beam x-ray source based DEI images are highly dependent on the electron distribution at the target. Uniform electron distribution by electron trajectory optimization is carried out through independent powering of the filaments inside the focusing cup. For higher electron beam current the x-ray flux satisfies obtaining a successful DEI image scan, but such high current increases the heat loading on the target. The target cooling with a contact cold finger does not provide sufficient thermal management, and hence not enough scanning time. The impinging jet nozzle cooling option was investigated to maximize convective heat transfer, and has shown feasible thermal management and adequate operation time for DEI imaging.

  15. Imprinting a Focused X-Ray Laser Beam to Measure Its Full Spatial Characteristics

    NASA Astrophysics Data System (ADS)

    Chalupský, J.; Boháček, P.; Burian, T.; Hájková, V.; Hau-Riege, S. P.; Heimann, P. A.; Juha, L.; Messerschmidt, M.; Moeller, S. P.; Nagler, B.; Rowen, M.; Schlotter, W. F.; Swiggers, M. L.; Turner, J. J.; Krzywinski, J.

    2015-07-01

    The new generation of x-ray free-electron lasers opens up unique avenues for exploring matter under exotic and extreme conditions. Extensive spatial characterization of focused, typically (sub)micron-sized, laser beams is indispensable but, nevertheless, difficult to be accomplished due to excessive radiation intensities. Methods exist allowing indirect or semidirect focus characterization from a safe distance far from the focal point. Here we present a direct method of in-focus numerical phase recovery exploiting multishot desorption imprints in poly(methyl methacrylate). Shapes of the imprints serve as input data for the newly developed code PhaRe (phase recovery), inspired by the iterative Gerchberg-Saxton algorithm. A procedure of dynamic input-output mixing guarantees that the algorithm always converges to a self-consistent paraxial Helmholtz equation solution, which is thereafter optimized for transverse spatial coherence. Very good agreement with single-shot ablation imprints in lead tungstate (PbWO4 ) is found. The experiment is carried out at the Linac Coherent Light Source with a focused beam monochromatized at 800 eV. The results of the coherence optimization indicate that the act of monochromatization may have an effect on otherwise very good transverse coherence of free-electron laser beams.

  16. Cone beam x-ray luminescence computed tomography: A feasibility study

    SciTech Connect

    Chen Dongmei; Zhu Shouping; Yi Huangjian; Zhang Xianghan; Chen Duofang; Liang Jimin; Tian Jie

    2013-03-15

    Purpose: The appearance of x-ray luminescence computed tomography (XLCT) opens new possibilities to perform molecular imaging by x ray. In the previous XLCT system, the sample was irradiated by a sequence of narrow x-ray beams and the x-ray luminescence was measured by a highly sensitive charge coupled device (CCD) camera. This resulted in a relatively long sampling time and relatively low utilization of the x-ray beam. In this paper, a novel cone beam x-ray luminescence computed tomography strategy is proposed, which can fully utilize the x-ray dose and shorten the scanning time. The imaging model and reconstruction method are described. The validity of the imaging strategy has been studied in this paper. Methods: In the cone beam XLCT system, the cone beam x ray was adopted to illuminate the sample and a highly sensitive CCD camera was utilized to acquire luminescent photons emitted from the sample. Photons scattering in biological tissues makes it an ill-posed problem to reconstruct the 3D distribution of the x-ray luminescent sample in the cone beam XLCT. In order to overcome this issue, the authors used the diffusion approximation model to describe the photon propagation in tissues, and employed the sparse regularization method for reconstruction. An incomplete variables truncated conjugate gradient method and permissible region strategy were used for reconstruction. Meanwhile, traditional x-ray CT imaging could also be performed in this system. The x-ray attenuation effect has been considered in their imaging model, which is helpful in improving the reconstruction accuracy. Results: First, simulation experiments with cylinder phantoms were carried out to illustrate the validity of the proposed compensated method. The experimental results showed that the location error of the compensated algorithm was smaller than that of the uncompensated method. The permissible region strategy was applied and reduced the reconstruction error to less than 2 mm. The robustness and stability were then evaluated from different view numbers, different regularization parameters, different measurement noise levels, and optical parameters mismatch. The reconstruction results showed that the settings had a small effect on the reconstruction. The nonhomogeneous phantom simulation was also carried out to simulate a more complex experimental situation and evaluated their proposed method. Second, the physical cylinder phantom experiments further showed similar results in their prototype XLCT system. With the discussion of the above experiments, it was shown that the proposed method is feasible to the general case and actual experiments. Conclusions: Utilizing numerical simulation and physical experiments, the authors demonstrated the validity of the new cone beam XLCT method. Furthermore, compared with the previous narrow beam XLCT, the cone beam XLCT could more fully utilize the x-ray dose and the scanning time would be shortened greatly. The study of both simulation experiments and physical phantom experiments indicated that the proposed method was feasible to the general case and actual experiments.

  17. SU-E-I-01: A Fast, Analytical Pencil Beam Based Method for First Order X-Ray Scatter Estimation of Kilovoltage Cone Beam X-Rays

    SciTech Connect

    Liu, J; Bourland, J

    2014-06-01

    Purpose: To analytically estimate first-order x-ray scatter for kV cone beam x-ray imaging with high computational efficiency. Methods: In calculating first-order scatter using the Klein-Nishina formula, we found that by integrating the point-to-point scatter along an interaction line, a “pencil-beam” scatter kernel (BSK) can be approximated to a quartic expression when the imaging field is small. This BSK model for monoenergetic, 100keV x-rays has been verified on homogeneous cube and cylinder water phantoms by comparing with the exact implementation of KN formula. For heterogeneous medium, the water-equivalent length of a BSK was acquired with an improved Siddon's ray-tracing algorithm, which was also used in calculating pre- and post- scattering attenuation. To include the electron binding effect for scattering of low-kV photons, the mean corresponding scattering angle is determined from the effective point of scattered photons of a BSK. The behavior of polyenergetic x-rays was also investigated for 120kV x-rays incident to a sandwiched infinite heterogeneous slab phantom, with the electron binding effect incorporated. Exact computation and Monte Carlo simulations were performed for comparisons, using the EGSnrc code package. Results: By reducing the 3D volumetric target (o(n{sup 3})) to 2D pencil-beams (o(n{sup 2})), the computation expense can be generally lowered by n times, which our experience verifies. The scatter distribution on a flat detector shows high agreement between the analytic BSK model and exact calculations. The pixel-to-pixel differences are within (-2%, 2%) for the homogeneous cube and cylinder phantoms and within (0, 6%) for the heterogeneous slab phantom. However, the Monte Carlo simulation shows increased deviation of the BSK model toward detector periphery. Conclusion: The proposed BSK model, accommodating polyenergetic x-rays and electron binding effect at low kV, shows great potential in efficiently estimating the first-order scatter from small imaging fields. We are investigating more thoroughly to improve performance and explore applications.

  18. Characteristics of a contract electron beam and bremsstrahlung (X-ray) irradiation facility of Radia industry

    NASA Astrophysics Data System (ADS)

    Takehisa, Masaaki; Saito, Toshio; Takahashi, Thoru; Sato, Yoshishige; Sato, Toshio

    1993-07-01

    A contract electron beam(EB) and bremsstrahlung(X-ray) facility with use of NHV 5 MeV, 30 mA Cock-Croft Walton machine is operational for EB since April 1991, and X-ray commercial irradiation was started in 1992 summer. The facility is consisted of the EB machine, bremsstrahlung target, chain and roller conveyor, and automatic turnover machine for dual sided irradiation. The operation of the system is fully controlled by LAN of personal computers for client's order, EB characteristics, beam current control proportional to the conveyor speed, turnover of product in processing mid point, and output of processing record to clients. The control and recording systems avoid human errors. This paper mainly discusses X-ray processing.

  19. Radiation exposure in a modern, circularly scanned-beam laminographic X-ray inspection system.

    PubMed

    Fazzio, R S

    1998-01-01

    Circularly scanned-beam laminography is currently the predominant technique used for the nondestructive examination of printed circuit solder assemblies via cross-sectional X-ray imaging. Given industry trends towards double-sided assemblies and limited access components, cross-sectional X-ray inspection is furthermore becoming increasingly important. Use of X-rays for inspection of solder joints on loaded printed circuit boards nonetheless often leads to concern surrounding possible undesirable radiation effects on the circuitry mounted on the board. In this paper we develop a simple analytical model useful for predicting the radiation exposure rates in a scanned-beam laminography system. We demonstrate the validity of the model through a series of dosimetry experiments. PMID:22388470

  20. Diamond monochromator for high heat flux synchrotron x-ray beams

    SciTech Connect

    Khounsary, A.M.; Smither, R.K.; Davey, S.; Purohit, A.

    1992-12-01

    Single crystal silicon has been the material of choice for x-ray monochromators for the past several decades. However, the need for suitable monochromators to handle the high heat load of the next generation synchrotron x-ray beams on the one hand and the rapid and on-going advances in synthetic diamond technology on the other make a compelling case for the consideration of a diamond mollochromator system. In this Paper, we consider various aspects, advantage and disadvantages, and promises and pitfalls of such a system and evaluate the comparative an monochromator subjected to the high heat load of the most powerful x-ray beam that will become available in the next few years. The results of experiments performed to evaluate the diffraction properties of a currently available synthetic single crystal diamond are also presented. Fabrication of diamond-based monochromator is within present technical means.

  1. Diamond monochromator for high heat flux synchrotron x-ray beams

    SciTech Connect

    Khounsary, A.M.; Smither, R.K.; Davey, S.; Purohit, A.

    1993-01-28

    Single crystal silicon has been the material of choice for x-ray monochromators for the past several decades. However, the need for suitable monochromators to handle the high heat load of the next generation synchrotron x-ray beams on the one hand and the rapid and on-going advances in synthetic diamond technology on the other make a compelling case for the consideration of a diamond monochromator system. In this paper, we consider various aspects, advantages and disadvantages, and promises and pitfalls of such a system and evaluate the comparative performance of a diamond monochromator subjected to the high heat load of the most powerful x-ray beam that will become available in the next few years. The results of experiments performed to evaluate the diffraction properties of a currently available synthetic single crystal diamond are also presented. Fabrication of a diamond-based monochromator is within present technical means.

  2. The influence of bowtie filtration on x-ray photons distribution in cone beam CT

    NASA Astrophysics Data System (ADS)

    Jiang, Shanghai; Feng, Peng; Wei, Biao; He, Peng; Deng, Luzhen; Zhang, Wei

    2015-10-01

    Bowtie filters are used to modulate an incoming x-ray beam as a function of the angle of the x-ray to balance the photon flux on a detector array. Because of their key roles in radiation dose reduction and multi-energy imaging, bowtie filters have attracted a major attention in modern X-ray computed tomography (CT). However, few researches are concerned on the effects of the structure and materials for the bowtie filter in the Cone Beam CT (CBCT). In this study, the influence of bowtie filters' structure and materials on X-ray photons distribution are analyzed using Monte Carlo (MC) simulations by MCNP5 code. In the current model, the phantom was radiated by virtual X-ray source (its' energy spectrum calculated by SpekCalc program) filtered using bowtie, then all photons were collected through array photoncounting detectors. In the process above, two bowtie filters' parameters which include center thickness (B), edge thickness (controlled by A), changed respectively. Two kinds of situation are simulated: 1) A=0.036, B=1, 2, 3, 4, 5, 6mm and the material is aluminum; 2) A=0.016, 0.036, 0.056, 0.076, 0.096, B=2mm and the material is aluminum. All the X-ray photons' distribution are measured through MCNP. The results show that reduction in center thickness and edge thickness can reduce the number of background photons in CBCT. Our preliminary research shows that structure parameters of bowtie filter can influence X-ray photons, furthermore, radiation dose distribution, which provide some evidences in design of bowtie filter for reducing radiation dose in CBCT.

  3. Radiation beam therapy evolution: From X-rays to hadrons

    SciTech Connect

    Khoroshkov, V. S.

    2006-10-15

    The history of external radiation beam therapy (radiotherapy)-in particular, proton therapy (PT)-is brietly outlined. Two possible strategies in increasing the efficacy of radiotherapy are considered. The radiotherapy methods and techniques are brietly described. The possibilities of PT in providing effective treatment and the main achievements are demonstrated. The state of the art in the PT development involving the active creation of large clinical PT centers since 1990 is analyzed.

  4. A preliminary investigation of cell growth after irradiation using a modulated x-ray intensity pattern

    NASA Astrophysics Data System (ADS)

    Bromley, Regina; Davey, Ross; Oliver, Lyn; Harvie, Rozelle; Baldock, Clive

    2006-08-01

    In this study we have investigated a spatial distribution of cell growth after their irradiation using a modulated x-ray intensity pattern. An A549 human non-small cell lung cancer cell line was grown in a 6-well culture. Two of the wells were the unirradiated control wells, whilst another two wells were irradiated with a modulated x-ray intensity pattern and the third two wells were uniformly irradiated. A number of plates were incubated for various times after irradiation and stained with crystal violet. The spatial distribution of the stained cells within each well was determined by measurement of the crystal violet optical density at multiple positions in the plate using a microplate photospectrometer. The crystal violet optical density for a range of cell densities was measured for the unirradiated well and this correlated with cell viability as determined by the MTT cell viability assay. An exponential dose response curve was measured for A549 cells from the average crystal violet optical density in the uniformly irradiated well up to a dose of 30 Gy. By measuring the crystal violet optical density distribution within a well the spatial distribution of cell growth after irradiation with a modulated x-ray intensity pattern can be plotted. This method can be used for in vitro investigation into the changes in radiation response associated with treatment using intensity modulated radiation therapy (IMRT).

  5. Generation of Attosecond X-ray Pulses Beyond the Atomic Unit of Time Using Laser Induced Microbunching in Electron Beams

    SciTech Connect

    Xiang, D.; Huang, Z.; Stupakov, G.; /SLAC

    2009-12-11

    Ever since the discovery of mode-locking, efforts have been devoted to reducing the duration of laser pulses since the ultrashort pulses are critical to explore the dynamics occurred on a ever-shorter timescale. In this paper we describe a scheme that's capable of generating intense attosecond x-ray pulses with duration beyond the atomic unit of time ({approx}24 attoseconds). The scheme combines the echo-enabled harmonic generation technique with the bunch compression which allows one to generate harmonic numbers of a few hundred in a microbunched beam through up-conversion of the frequency of a UV seed laser. A few-cycle intense IR laser is used to generate the required energy chirp in the beam for bunch compression and for selection of an attosecond x-ray pulse. Using a representative realistic set of parameters, we show that 1 nm x-ray pulse with peak power of a few hundred MW and duration as short as 20 attoseconds (FWHM) can be generated from a 200 nm UV seed laser. The proposed scheme may enable the study of electronic dynamics with a resolution beyond the atomic unit of time and may open a new regime of ultrafast sciences.

  6. THE X-RAY DETECTABILITY OF ELECTRON BEAMS ESCAPING FROM THE SUN

    SciTech Connect

    Saint-Hilaire, Pascal; Krucker, Saem; Christe, Steven; Lin, Robert P.

    2009-05-01

    We study the detectability and characterization of electron beams as they leave their acceleration site in the low corona toward interplanetary space through their nonthermal X-ray bremsstrahlung emission. We demonstrate that the largest interplanetary electron beams ({approx}>10{sup 35} electrons above 10 keV) can be detected in X-rays with current and future instrumentation, such as RHESSI or the X-Ray Telescope (XRT) onboard Hinode. We make a list of optimal observing conditions and beam characteristics. Amongst others, good imaging (as opposed to mere localization or detection in spatially integrated data) is required for proper characterization, putting the requirement on the number of escaping electrons (above 10 keV) to {approx}>3 x 10{sup 36} for RHESSI, {approx}>3 x 10{sup 35} for Hinode/XRT, and {approx}>10{sup 33} electrons for the FOXSI sounding rocket scheduled to fly in 2011. Moreover, we have found that simple modeling hints at the possibility that coronal soft X-ray jets could be the result of local heating by propagating electron beams.

  7. X-ray spectroscopy of highly-ionized atoms in an electron beam ion trap (EBIT)

    SciTech Connect

    Marrs, R.E.; Bennett, C.; Chen, M.H.; Cowan, T.; Dietrich, D.; Henderson, J.R.; Knapp, D.A.; Levine, M.A.; Schneider, M.B.; Scofield, J.H.

    1988-01-01

    An Electron Beam Ion Trap at Lawrence Livermore National Laboratory is being used to produce and trap very-highly-charged-ions (q /le/ 70+) for x-ray spectroscopy measurements. Recent measurements of dielectronic recombination, electron impact excitation and transition energies are presented. 15 refs., 12 figs., 1 tab.

  8. Ultra-thin optical grade scCVD diamond as X-ray beam position monitor.

    PubMed

    Desjardins, Kewin; Pomorski, Michal; Morse, John

    2014-11-01

    Results of measurements made at the SIRIUS beamline of the SOLEIL synchrotron for a new X-ray beam position monitor based on a super-thin single crystal of diamond grown by chemical vapor deposition (CVD) are presented. This detector is a quadrant electrode design processed on a 3?m-thick membrane obtained by argon-oxygen plasma etching the central area of a CVD-grown diamond plate of 60?m thickness. The membrane transmits more than 50% of the incident 1.3?keV energy X-ray beam. The diamond plate was of moderate purity (?1?p.p.m. nitrogen), but the X-ray beam induced current (XBIC) measurements nevertheless showed a photo-charge collection efficiency approaching 100% for an electric field of 2?V?m(-1), corresponding to an applied bias voltage of only 6?V. XBIC mapping of the membrane showed an inhomogeneity of more than 10% across the membrane, corresponding to the measured variation in the thickness of the diamond plate before the plasma etching process. The measured XBIC signal-to-dark-current ratio of the device was greater than 10(5), and the X-ray beam position resolution of the device was better than a micrometer for a 1?kHz sampling rate. PMID:25343787

  9. Investigation of tomosynthetic perfusion measurements using the scanning-beam digital x-ray (SBDX) system

    NASA Astrophysics Data System (ADS)

    Nett, Brian E.; Chen, Guang-Hong; Van Lysel, Michael S.; Betts, Timothy; Speidel, Michael; Rowley, Howard A.; Aagaard Kienitz, Beverly D.; Mistretta, Charles A.

    2004-10-01

    The feasibility of making regional perfusion measurements using a tomosynthetic digital subtraction angiography (TDSA) acquisition has been demonstrated. The study of tomosynthetic perfusion measurements was motivated by the clinical desire for perfusion measurements in an interventional angiography suite. These pilot studies were performed using the scanning-beam digital x-ray (SBDX) system which is an inverse-geometry imaging device which utilizes an electromagnetically-scanned x-ray source, and a small CdTe direct conversion photon counting detector. The scanning electron source was used to acquire planar-tomographic images of a 12.5 x 12.5 cm field of view at a frame rate of 15 frames/sec during dynamic contrast injection. A beagle animal model was used to evaluate the tomosynthetic perfusion measurements. A manual bolus injection of iodinated contrast solution was used in order to resolve the parameters of the contrast pass curve. The acquired planar tomosynthetic dataset was reconstructed with a simple back-projection algorithm. Digital subtraction techniques were used to visualize the change in contrast agent intensity in each reconstructed plane. Given the TDSA images, region of interest based analysis was used in the selection of the image pixels corresponding to the artery and tissue bed. The mean transit time (MTT), regional cerebral blood volume (rCBV) and regional cerebral blood flow (rCBF) were extracted from the tomosynthetic data for selected regions in each of the desired reconstructed planes. For the purpose of this study, the arterial contrast enhancement curve was fit with a combination of gamma variate terms, and the MTT was calculated using a deconvolution based on the singular value decomposition (SVD). The results of the contrast pass curves derived with TDSA were consistent with the results from perfusion measurements as implemented with CT acquisition.

  10. Design and initial characterisation of X-ray beam diagnostic imagers for the European XFEL

    NASA Astrophysics Data System (ADS)

    Koch, Andreas; Freund, Wolfgang; Grnert, Jan; Planas, Marc; Roth, Thomas; Samoylova, Liubov; Lyamayev, Viktor

    2015-05-01

    The European X-Ray Free-Electron-Laser facility requires diagnostics of its x-ray photon beam. Besides other diagnostic components, imaging stations will be employed for the characterisation of beam properties like position, profile, and pointing, before and after different types of mirrors, slits and monochromators. In combination with soft x-ray grating monochromators or other dispersive devices, imagers can also deliver spectral information. The imagers will usually absorb the beam (invasive devices), however, for some applications they will be partially transmissive to allow for beam pointing monitoring together with a second imaging unit further downstream. For the first commissioning 25 diagnostic imagers are planned at various positions in the photon beam tunnels. Further similar devices are under development for monitoring the beam properties at the experimental stations. The design of theses imaging stations will be described. Initial testing has started and the optimization of some components will be reported. The main components of these imaging stations are: retractable scintillators for conversion of x-rays to visible light, mirrors, optics and CCD / CMOS cameras for image recording, an ultra-high vacuum (UHV) chamber, and the associated control electronics and software. Scintillators and mirrors will be the only components in an ultra-high vacuum chamber. Performance characteristics are addressed, especially mechanical stability, spatial resolution, signal-to-noise properties, and radiation hardness. The challenge in the design is to deal with a wide range of beam properties: photon energies from 0.26 - 25 keV, beam sizes from several 100 ?m to several mm, large beam position shifts of up to 120 mm, pulse durations of 10 fs and pulse energies up to 10 mJ which may destroy materials by a single pulse.

  11. Development of high-resolution x-ray CT system using parallel beam geometry

    NASA Astrophysics Data System (ADS)

    Yoneyama, Akio; Baba, Rika; Hyodo, Kazuyuki; Takeda, Tohoru; Nakano, Haruhisa; Maki, Koutaro; Sumitani, Kazushi; Hirai, Yasuharu

    2016-01-01

    For fine three-dimensional observations of large biomedical and organic material samples, we developed a high-resolution X-ray CT system. The system consists of a sample positioner, a 5-μm scintillator, microscopy lenses, and a water-cooled sCMOS detector. Parallel beam geometry was adopted to attain a field of view of a few mm square. A fine three-dimensional image of birch branch was obtained using a 9-keV X-ray at BL16XU of SPring-8 in Japan. The spatial resolution estimated from the line profile of a sectional image was about 3 μm.

  12. X-ray beam stabilization at BL-17A, the protein microcrystallography beamline of the Photon Factory

    PubMed Central

    Igarashi, Noriyuki; Ikuta, Kazuyuki; Miyoshi, Toshinobu; Matsugaki, Naohiro; Yamada, Yusuke; Yousef, Mohammad S.; Wakatsuki, Soichi

    2008-01-01

    BL-17A is a new structural biology beamline at the Photon Factory, Japan. The high-brilliance beam, derived from the new short-gap undulator (SGU#17), allows for unique protein crystallographic experiments such as data collection from microcrystals and structural determination using softer X-rays. However, microcrystal experiments require robust beam stability during data collection and minor fluctuations could not be ignored. Initially, significant beam instability was observed at BL-17A. The causes of the beam instability were investigated and its various sources identified. Subsequently, several effective countermeasures have been implemented, and the fluctuation of the beam intensity successfully suppressed to within 1%. Here the instability reduction techniques used at BL-17A are presented. PMID:18421162

  13. The effect of beam-driven return current instability on solar hard X-ray bursts

    NASA Technical Reports Server (NTRS)

    Cromwell, D.; Mcquillan, P.; Brown, J. C.

    1986-01-01

    The problem of electrostatic wave generation by a return current driven by a small area electron beam during solar hard X-ray bursts is discussed. The marginal stability method is used to solve numerically the electron and ion heating equations for a prescribed beam current evolution. When ion-acoustic waves are considered, the method appears satisfactory and, following an initial phase of Coulomb resistivity in which T sub e/T sub i rise, predicts a rapid heating of substantial plasma volumes by anomalous ohmic dissipation. This hot plasma emits so much thermal bremsstrahlung that, contrary to previous expectations, the unstable beam-plasma system actually emits more hard X-rays than does the beam in the purely collisional thick target regime relevant to larger injection areas. Inclusion of ion-cyclotron waves results in ion-acoustic wave onset at lower T sub e/T sub i and a marginal stability treatment yields unphysical results.

  14. Synchrotron-based coherent scatter x-ray projection imaging using an array of monoenergetic pencil beams

    NASA Astrophysics Data System (ADS)

    Landheer, Karl; Johns, Paul C.

    2012-09-01

    Traditional projection x-ray imaging utilizes only the information from the primary photons. Low-angle coherent scatter images can be acquired simultaneous to the primary images and provide additional information. In medical applications scatter imaging can improve x-ray contrast or reduce dose using information that is currently discarded in radiological images to augment the transmitted radiation information. Other applications include non-destructive testing and security. A system at the Canadian Light Source synchrotron was configured which utilizes multiple pencil beams (up to five) to create both primary and coherent scatter projection images, simultaneously. The sample was scanned through the beams using an automated step-and-shoot setup. Pixels were acquired in a hexagonal lattice to maximize packing efficiency. The typical pitch was between 1.0 and 1.6 mm. A Maximum Likelihood-Expectation Maximization-based iterative method was used to disentangle the overlapping information from the flat panel digital x-ray detector. The pixel value of the coherent scatter image was generated by integrating the radial profile (scatter intensity versus scattering angle) over an angular range. Different angular ranges maximize the contrast between different materials of interest. A five-beam primary and scatter image set (which had a pixel beam time of 990 ms and total scan time of 56 min) of a porcine phantom is included. For comparison a single-beam coherent scatter image of the same phantom is included. The muscle-fat contrast was 0.10 0.01 and 1.16 0.03 for the five-beam primary and scatter images, respectively. The air kerma was measured free in air using aluminum oxide optically stimulated luminescent dosimeters. The total area-averaged air kerma for the scan was measured to be 7.2 0.4 cGy although due to difficulties in small-beam dosimetry this number could be inaccurate.

  15. Possibilities of Controlling an X-ray Beam with a Crystal Subjected to Long-Wave Ultrasonic Vibrations

    SciTech Connect

    Blagov, A.E.; Lider, V.V.; Pisarevskii, Yu.V.; Koval'chuk, M.V.; Kohn, V.G.

    2005-11-01

    X-ray diffraction is experimentally studied in the Laue geometry in a germanium crystal carrying a long-wave ultrasonic wave that creates an alternating lattice deformation along the sample surface. Stroboscopic equipment is used to separate different phases and, correspondingly, different profiles of a spatial deformation distribution from the periodic deformation. A uniform deformation is shown to change the angular position of the X-ray beam, and a nonuniform deformation broadens the angular region of reflection and decreases the peak intensity. Ultrasound can be used to compensate for the static deformation at the place where the single-crystal sample and the resonator are glued together. Apart from the fundamental long-wave harmonic, the crystal contains a parasitic deformation with a shorter wavelength. A simple theoretical model is developed, and it rather accurately describes the experimental results.

  16. Measuring the Impact of AGN Outflows via Intensive UV and X-ray Monitoring Campaigns

    NASA Astrophysics Data System (ADS)

    Kriss, Gerard

    2015-08-01

    Observations of AGN outflows have progressed from the era of single-object surveys to intensive monitoring campaigns spanning weeks to months. The combination of multiple observations, improved temporal coverage, multi-wavelength monitoring in both the X-ray and UV bands, and the baseline of prior historical observations has enabled determinations of the locations, mass flux, and kinetic luminosities of the outflowing absorbing gas in several AGN, notably Mrk 509, NGC 5548, Mrk 335, and NGC 985. Another intensive campaign is planned for 2015-2016 on NGC 7469. In all cases, the mass flux and kinetic energy is dominated by the higher-ionization X-ray absorbing gas. But the higher-resolution UV observations give a kinematically resolved picture of the overall outflow. In most cases, the outflowing gas is located at parsec to kpc scales, with insufficient kinetic luminosity to have an evolutionary impact on the host galaxy. Typically, the kinetic luminosity is less than a percent of the Eddington luminosity. In some cases, transient, broad UV absorption troughs have appeared (e.g., Mrk 335 and NGC 5548), with variability timescales suggesting locations near the broad-line region of the AGN. Yet these higher-velocity outflows also have low-impact kinetic luminosities. In the best-studied case of NGC 5548, the strength of the broad UV absorption lines varies with the degree of soft X-ray obscuration first revealed by XMM-Newton spectra. The lower-ionization, narrow associated absorption lines in the UV spectrum of NGC 5548 that appeared concurrently with the soft X-ray obscuration vary in response to the changing UV flux on a daily basis. The intensive monitoring allows us to fit time-dependent photoionization models to the UV-absorbing gas, allowing precise determinations of the locations, mass flux, and kinetic luminosities of the absorbers.

  17. X-ray spectra of Hercules X-1. 2: Intrinsic beam

    NASA Technical Reports Server (NTRS)

    Pravdo, S. H.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.

    1977-01-01

    The X-ray spectrum of Hercules X-1 was observed in the energy range 2-24 keV with sufficient temporal resolution to allow detailed study of spectral correlations with the 1.24 sec pulse phase. A region of spectral hardening which extends over approximately the 1/10 pulse phase may be associated with the underlying beam. The pulse shape stability and its asymmetry relative to this intrinsic beam are discussed.

  18. Scaling of Pressure with Intensity in Laser-Driven Shocks and Effects of Hot X-Ray Preheat

    SciTech Connect

    Colvin, Jeffrey D.; Kalantar, Daniel H.

    2006-07-28

    To drive shocks into solids with a laser we either illuminate the material directly, or to get higher pressures, illuminate a plastic ablator that overlays the material of interest. In both cases the illumination intensity is low, <<1013 W/cm2, compared to that for traditional laser fusion targets. In this regime, the laser beam creates and interacts with a collisional, rather than a collisionless, plasma. We present scaling relationships for shock pressure with intensity derived from simulations for this low-intensity collisional plasma regime. In addition, sometimes the plastic-ablator targets have a thin flash-coating of Al on the plastic surface as a shine-through barrier; this Al layer can be a source of hot x-ray preheat. We discuss how the preheat affects the shock pressure, with application to simulating VISAR measurements from experiments conducted on various lasers on shock compression of Fe.

  19. Scaling of Pressure with Intensity in Laser-Driven Shocks and Effects of Hot X-ray Preheat

    SciTech Connect

    Colvin, J D; Kalantar, D H

    2005-08-29

    To drive shocks into solids with a laser we either illuminate the material directly, or to get higher pressures, illuminate a plastic ablator that overlays the material of interest. In both cases the illumination intensity is low, <<10{sup 13} W/cm{sup 2}, compared to that for traditional laser fusion targets. In this regime, the laser beam creates and interacts with a collisional, rather than a collisionless, plasma. We present scaling relationships for shock pressure with intensity derived from simulations for this low-intensity collisional plasma regime. In addition, sometimes the plastic-ablator targets have a thin flashcoating of Al on the plastic surface as a shine-through barrier; this Al layer can be a source of hot x-ray preheat. We discuss how the preheat affects the shock pressure, with application to simulating VISAR measurements from experiments conducted on various lasers on shock compression of Fe.

  20. Directionality effects in the transfer of X-rays from a magnetized atmosphere: Beam pulse shape

    NASA Technical Reports Server (NTRS)

    Meszaros, P.; Bonazzola, S.

    1981-01-01

    A formalism is presented for radiation transfer in two normal polarization modes in finite and semiinfinite plane parallel uniform atmospheres with a magnetic field perpendicular to the surface and arbitrary propagation angles. This method is based on the coupled integral equations of transfer, including emission, absorption, and scattering. Calculations are performed for atmosphere parameters typical of X-ray pulsars. The directionality of the escaping radiation is investigated for several cases, varying the input distributions. Theoretical pencil beam profiles and X-ray pulse shapes are obtained assuming the radiation is emitted from the polar caps of spinning neutron stars. Implications for realistic models of accreting magnetized X-ray sources are briefly discussed.

  1. Thermal Acoustic Sensor for High Pulse Energy X-ray FEL Beams

    SciTech Connect

    Smith, T.J.; Frisch, J.C.; Kraft, E.M.; Loos, J.; Bentsen, G.S.; /Rochester U.

    2011-12-13

    The pulse energy density of X-ray FELs will saturate or destroy conventional X-ray diagnostics, and the use of large beam attenuation will result in a beam that is dominated by harmonics. We present preliminary results at the LCLS from a pulse energy detector based on the thermal acoustic effect. In this type of detector an X-ray resistant material (boron carbide in this system) intercepts the beam. The pulse heating of the target material produces an acoustic pulse that can be detected with high frequency microphones to produce a signal that is linear in the absorbed energy. The thermal acoustic detector is designed to provide first- and second-order calorimetric measurement of X-ray FEL pulse energy. The first-order calorimetry is a direct temperature measurement of a target designed to absorb all or most of the FEL pulse power with minimal heat leak. The second-order measurement detects the vibration caused by the rapid thermoelastic expansion of the target material each time it absorbs a photon pulse. Both the temperature change and the amplitude of the acoustic signal are directly related to the photon pulse energy.

  2. Markerless Lung Tumor Motion Tracking by Dynamic Decomposition of X-Ray Image Intensity

    PubMed Central

    Takai, Yoshihiro; Endo, Haruna; Narita, Yuichiro; Zhang, Xiaoyong; Sakai, Masao; Osanai, Makoto; Abe, Makoto; Yoshizawa, Makoto

    2013-01-01

    We propose a new markerless tracking technique of lung tumor motion by using an X-ray fluoroscopic image sequence for real-time image-guided radiation therapy (IGRT). A core innovation of the new technique is to extract a moving tumor intensity component from the fluoroscopic image intensity. The fluoroscopic intensity is the superimposition of intensity components of all the structures passed through by the X-ray. The tumor can then be extracted by decomposing the fluoroscopic intensity into the tumor intensity component and the others. The decomposition problem for more than two structures is ill posed, but it can be transformed into a well-posed one by temporally accumulating constraints that must be satisfied by the decomposed moving tumor component and the rest of the intensity components. The extracted tumor image can then be used to achieve accurate tumor motion tracking without implanted markers that are widely used in the current tracking techniques. The performance evaluation showed that the extraction error was sufficiently small and the extracted tumor tracking achieved a high and sufficient accuracy less than 1 mm for clinical datasets. These results clearly demonstrate the usefulness of the proposed method for markerless tumor motion tracking.

  3. Intense high repetition rate Mo K? x-ray source generated from laser solid interaction for imaging application

    SciTech Connect

    Huang, K.; Li, M. H.; Yan, W. C.; Ma, Y.; Zhao, J. R.; Li, Y. F.; Chen, L. M.; Guo, X.; Li, D. Z.; Chen, Y. P.; Zhang, J.

    2014-11-15

    We report an efficient Mo K? x-ray source produced by interaction of femtosecond Ti: sapphire laser pulses with a solid Molybdenum target working at 1 kHz repetition rate. The generated Mo K? x-ray intensity reaches to 4.7 10{sup 10} photons?sr{sup ?1}?s{sup ?1}, corresponding to an average power of 0.8 mW into 2? solid angle. The spatial resolution of this x-ray source is measured to be 26 lp/mm. With the high flux and high spatial resolution characteristics, high resolving in-line x-ray radiography was realized on test objects and large size biological samples within merely half a minute. This experiment shows the possibility of laser plasma hard x-ray source as a new low cost and high resolution system for radiography and its ability of ultrafast x-ray pump-probe study of matter.

  4. Electron beam-based sources of ultrashort x-ray pulses.

    SciTech Connect

    Zholents, A.; Accelerator Systems Division

    2010-09-30

    A review of various methods for generation of ultrashort x-ray pulses using relativistic electron beam from conventional accelerators is presented. Both spontaneous and coherent emission of electrons is considered. The importance of the time-resolved studies of matter at picosecond (ps), femtosecond (fs), and atttosecond (as) time scales using x-rays has been widely recognized including by award of a Nobel Prize in 1999 [Zewa]. Extensive reviews of scientific drivers can be found in [BES1, BES2, BES3, Lawr, Whit]. Several laser-based techniques have been used to generate ultrashort x-ray pulses including laser-driven plasmas [Murn, Alte, Risc, Rose, Zamp], high-order harmonic generation [Schn, Rund, Wang, Arpi], and laser-driven anode sources [Ande]. In addition, ultrafast streak-camera detectors have been applied at synchrotron sources to achieve temporal resolution on the picosecond time scale [Wulf, Lind1]. In this paper, we focus on a different group of techniques that are based on the use of the relativistic electron beam produced in conventional accelerators. In the first part we review several techniques that utilize spontaneous emission of electrons and show how solitary sub-ps x-ray pulses can be obtained at existing storage ring based synchrotron light sources and linacs. In the second part we consider coherent emission of electrons in the free-electron lasers (FELs) and review several techniques for a generation of solitary sub-fs x-ray pulses. Remarkably, the x-ray pulses that can be obtained with the FELs are not only significantly shorter than the ones considered in Part 1, but also carry more photons per pulse by many orders of magnitude.

  5. TU-A-9A-09: Proton Beam X-Ray Fluorescence CT

    SciTech Connect

    Bazalova, M; Ahmad, M; Fahrig, R; Xing, L

    2014-06-15

    Purpose: To evaluate x-ray fluorescence computed tomography induced with proton beams (pXFCT) for imaging of gold contrast agent. Methods: Proton-induced x-ray fluorescence was studied by means of Monte Carlo (MC) simulations using TOPAS, a MC code based on GEANT4. First, proton-induced K-shell and L-shell fluorescence was studied as a function of proton beam energy and 1) depth in water and 2) size of contrast object. Second, pXFCT images of a 2-cm diameter cylindrical phantom with four 5- mm diameter contrast vials and of a 20-cm diameter phantom with 1-cm diameter vials were simulated. Contrast vials were filled with water and water solutions with 1-5% gold per weight. Proton beam energies were varied from 70-250MeV. pXFCT sinograms were generated based on the net number of gold K-shell or L-shell x-rays determined by interpolations from the neighboring 0.5keV energy bins of spectra collected with an idealized 4π detector. pXFCT images were reconstructed with filtered-back projection, and no attenuation correction was applied. Results: Proton induced x-ray fluorescence spectra showed very low background compared to x-ray induced fluorescence. Proton induced L-shell fluorescence had a higher cross-section compared to K-shell fluorescence. Excitation of L-shell fluorescence was most efficient for low-energy protons, i.e. at the Bragg peak. K-shell fluorescence increased with increasing proton beam energy and object size. The 2% and 5% gold contrast vials were accurately reconstructed in K-shell pXFCT images of both the 2-cm and 20-cm diameter phantoms. Small phantom L-shell pXFCT image required attenuation correction and had a higher sensitivity for 70MeV protons compared to 250MeV protons. With attenuation correction, L-shell pXFCT might be a feasible option for imaging of small size (∼2cm) objects. Imaging doses for all simulations were 5-30cGy. Conclusion: Proton induced x-ray fluorescence CT promises to be an alternative quantitative imaging technique to the commonly considered XFCT imaging with x-ray beams.

  6. Electron Beam-Target Interaction and Spot Size Stabilization in Flash X-Ray Radiography*

    NASA Astrophysics Data System (ADS)

    Kwan, Thomas J. T.

    1999-11-01

    The Dual Axis Radiographic Hydro-Test (DARHT) facility is one of the most important capabilities in science based stockpile stewardship program of the US Department of Energy. DARHT uses an intense relativistic electron beam (20 MeV, 2-4 kA) to provide the necessary dose and a very small radiation spot size ( 1 mm) to achieve the desired optical resolution. Linear induction accelerator technology and electron beam diode technology can produce beams with the desirable characteristics. However, the high current densities at the converter target will cause strong nonlinear effects, which can adversely influence the radiographic performance. Over a time scale of tens of nanoseconds, intense space charge fields of the electron beam will extract positively charged ions from the vaporized target. These ions will partially neutralize the electron beam, reducing its Coulomb self-repulsive force. Initially the beam will pinch near the target, giving a favorable reduction in spot size but possibly degrading the beam quality. The ion column will then propagate upstream, moving the location of the pinch away from the target. The beam will pinch on axis and expand, producing a progressive increase in spot size as the pinch migrates upstream. This phenomenon can severely degrade resolution. In multiple-pulse applications where longer time scale phenomena become important, the expanding plasma plume of the vaporized target material can cause disruption of subsequent electron beam pulses. In this study, we investigate the physics of beam transport and explore methods for mitigating the undesirable effects. Theoretical models have been developed and validated against available experimental data from the Los Alamos Integrated Test Stand (ITS). It is shown that ion propagation can be suppressed by applying a negative bias potential to the target. The ions then become trapped in the target vicinity and actually reduce the spot size rather than increasing it due to the additional ion focusing. The negative bias can be created by inductively isolating the target, by an external voltage source, or most simply by using charge deposition from the electron beam itself to resistively bias the target. An alternative approach utilizes a very thin upstream barrier foil that is transparent to the incoming electron beam but opaque to the lower-velocity ions. Simulations indicate that any of these methods can effectively stabilize the beam spot size. The self-biasing target concept was implemented and tested on the ITS machine and performed as predicted. Computer simulations and data from these experiments allowed us to predict the time scale for ion emission and identify the ion species present. Another key factor is the influence of beam pinch and emittance growth on the radiative output. Results from our beam transport calculations have been linked to a Monte Carlo code to analyze the quantitative impact on the x-ray output spectrum. The presentation will focus on the physics of converter targets and on designs applicable to the DARHT radiographic facility.

  7. Intense Electron Beam Sources for Flash Radiography

    NASA Astrophysics Data System (ADS)

    Maenchen, J. E.; Hahn, K.; Kincy, M.; Kitterman, D.; Lucero, R.; Menge, P. R.; Molina, I.; Olson, C.; Rovang, D. C.; Fulton, R. D.; Carlson, R.; Smith, J.; Martinson, D.; Droemer, D.; Gignac, R.; Helvin, T.; Ormand, E.; Wilkins, F.; Welch, D. R.; Oliver, B. V.; Rose, D. V.; Bailey, V.; Corcoran, P.; Johnson, D. L.; Smith, I. D.; Weidenheimer, D.; Cooperstein, G.; Commisso, R.; Mosher, D.; Stephanakis, S.; Schumer, J.; Swanekamp, S.; Young, F.; Goldsack, T. J.; Cooper, G. M.; Pearce, A. G.; Phillips, M. A.; Sinclair, M. A.; Thomas, K. J.; Williamson, M.; Cordova, S.; Woodring, R.; Schamiloglu, E.

    2002-12-01

    High intensity pulsed electron beams are used to create bremsstrahlung x-ray sources for flash radiographic interrogation of dynamic experiments. Typical industrial sources operate below 200 GW/cm2 intensities, while experimental requirements can demand above 50 TW/cm2. Recent developments in pulsed power-driven high intensity electron beam systems have significantly increased these operating regimes, demonstrating 20 TW/cm2, and computations predict successful extrapolation to higher intensities. Detailed studies of electron beam configurations, both theoretical and experimental, and the prognosis for each to increase to the required levels is discussed.

  8. In situ surface/interface x-ray diffractometer for oxide molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Lee, J. H.; Tung, I. C.; Chang, S.-H.; Bhattacharya, A.; Fong, D. D.; Freeland, J. W.; Hong, Hawoong

    2016-01-01

    In situ studies of oxide molecular beam epitaxy by synchrotron x-ray scattering has been made possible by upgrading an existing UHV/molecular beam epitaxy (MBE) six-circle diffractometer system. For oxide MBE growth, pure ozone delivery to the chamber has been made available, and several new deposition sources have been made available on a new 12 in. CF (ConFlat, a registered trademark of Varian, Inc.) flange. X-ray diffraction has been used as a major probe for film growth and structures for the system. In the original design, electron diffraction was intended for the secondary diagnostics available without the necessity of the x-ray and located at separate positions. Deposition of films was made possible at the two diagnostic positions. And, the aiming of the evaporation sources is fixed to the point between two locations. Ozone can be supplied through two separate nozzles for each location. Also two separate thickness monitors are installed. Additional features of the equipment are also presented together with the data taken during typical oxide film growth to illustrate the depth of information available via in situ x-ray techniques.

  9. X-Ray Scatter Correction on Soft Tissue Images for Portable Cone Beam CT

    PubMed Central

    Aootaphao, Sorapong; Thongvigitmanee, Saowapak S.; Rajruangrabin, Jartuwat; Thanasupsombat, Chalinee; Srivongsa, Tanapon; Thajchayapong, Pairash

    2016-01-01

    Soft tissue images from portable cone beam computed tomography (CBCT) scanners can be used for diagnosis and detection of tumor, cancer, intracerebral hemorrhage, and so forth. Due to large field of view, X-ray scattering which is the main cause of artifacts degrades image quality, such as cupping artifacts, CT number inaccuracy, and low contrast, especially on soft tissue images. In this work, we propose the X-ray scatter correction method for improving soft tissue images. The X-ray scatter correction scheme to estimate X-ray scatter signals is based on the deconvolution technique using the maximum likelihood estimation maximization (MLEM) method. The scatter kernels are obtained by simulating the PMMA sheet on the Monte Carlo simulation (MCS) software. In the experiment, we used the QRM phantom to quantitatively compare with fan-beam CT (FBCT) data in terms of CT number values, contrast to noise ratio, cupping artifacts, and low contrast detectability. Moreover, the PH3 angiography phantom was also used to mimic human soft tissues in the brain. The reconstructed images with our proposed scatter correction show significant improvement on image quality. Thus the proposed scatter correction technique has high potential to detect soft tissues in the brain.

  10. X-Ray Scatter Correction on Soft Tissue Images for Portable Cone Beam CT.

    PubMed

    Aootaphao, Sorapong; Thongvigitmanee, Saowapak S; Rajruangrabin, Jartuwat; Thanasupsombat, Chalinee; Srivongsa, Tanapon; Thajchayapong, Pairash

    2016-01-01

    Soft tissue images from portable cone beam computed tomography (CBCT) scanners can be used for diagnosis and detection of tumor, cancer, intracerebral hemorrhage, and so forth. Due to large field of view, X-ray scattering which is the main cause of artifacts degrades image quality, such as cupping artifacts, CT number inaccuracy, and low contrast, especially on soft tissue images. In this work, we propose the X-ray scatter correction method for improving soft tissue images. The X-ray scatter correction scheme to estimate X-ray scatter signals is based on the deconvolution technique using the maximum likelihood estimation maximization (MLEM) method. The scatter kernels are obtained by simulating the PMMA sheet on the Monte Carlo simulation (MCS) software. In the experiment, we used the QRM phantom to quantitatively compare with fan-beam CT (FBCT) data in terms of CT number values, contrast to noise ratio, cupping artifacts, and low contrast detectability. Moreover, the PH3 angiography phantom was also used to mimic human soft tissues in the brain. The reconstructed images with our proposed scatter correction show significant improvement on image quality. Thus the proposed scatter correction technique has high potential to detect soft tissues in the brain. PMID:27022608

  11. Monte Carlo model of the scanning beam digital x-ray (SBDX) source.

    PubMed

    Bazalova, M; Weil, M D; Wilfley, B; Graves, E E

    2012-11-21

    The scanning-beam digital x-ray (SBDX) system has been developed for fluoroscopic imaging using an inverse x-ray imaging geometry. The SBDX system consists of a large-area x-ray source with a multihole collimator and a small detector. The goal of this study was to build a Monte Carlo (MC) model of the SBDX source as a useful tool for optimization of the SBDX imaging system in terms of its hardware components and imaging parameters. The MC model of the source was built in the EGSnrc/BEAMnrc code and validated using the DOSXYZnrc code and Gafchromic film measurements for 80, 100, and 120kV x-ray source voltages. The MC simulated depth dose curves agreed with measurements to within 5%, and beam profiles at three selected depths generally agreed within 5%. Exposure rates and half-value layers for three voltages were also calculated from the MC simulations. Patient skin-dose per unit detector-dose was quantified as a function of patient size for all three x-ray source voltages. The skin-dose to detector-dose ratio ranged from 5-10 for a 20cm thick patient to 1נ10(3)-1נ10(5)for a 50cm patient for the 120 and 80kV beams, respectively. Simulations of imaging dose for a prostate patient using common imaging parameters revealed that skin-dose per frame was as low as 0.2 mGy. PMID:23093305

  12. Mapping the continuous reciprocal space intensity distribution of X-ray serial crystallography

    PubMed Central

    Yefanov, Oleksandr; Gati, Cornelius; Bourenkov, Gleb; Kirian, Richard A.; White, Thomas A.; Spence, John C. H.; Chapman, Henry N.; Barty, Anton

    2014-01-01

    Serial crystallography using X-ray free-electron lasers enables the collection of tens of thousands of measurements from an equal number of individual crystals, each of which can be smaller than 1 m in size. This manuscript describes an alternative way of handling diffraction data recorded by serial femtosecond crystallography, by mapping the diffracted intensities into three-dimensional reciprocal space rather than integrating each image in two dimensions as in the classical approach. We call this procedure three-dimensional merging. This procedure retains information about asymmetry in Bragg peaks and diffracted intensities between Bragg spots. This intensity distribution can be used to extract reflection intensities for structure determination and opens up novel avenues for post-refinement, while observed intensity between Bragg peaks and peak asymmetry are of potential use in novel direct phasing strategies. PMID:24914160

  13. Electron beam stability and beam peak to peak motion data for NSLS X-Ray storage ring

    SciTech Connect

    Singh, O.

    1993-07-01

    In the past two years, a significant reduction in electron beam motion has been achieved at the NSLS X-Ray storage ring. The implementation of global analog orbit feedbacks, based on a harmonics correction scheme, has reduced the beam motion globally. Implementation of six local analog feedback systems has reduced the beam motion even further at the corresponding beam line straight sections. This paper presents beam motion measurements, showing the improvement due to the feedback systems. Beam motion is measured using a spectrum analyzer and data is presented at various frequencies, where peaks were observed. Finally, some of the beam motion sources are discussed.

  14. Performance of X-ray Beam lines at Superconducting Wavelength Shifter

    SciTech Connect

    Song, Y. F.; Chang, C. H.; Liu, C. Y.; Chang, S. H.; Jeng, U.; Lai, Y. H.; Liu, D. G.; Yin, G. C.; Lee, J. F.; Sheu, H. S.; Chung, S. C.; Tsang, K. L.; Liang, K. S.; Hwu, Y.

    2007-01-19

    To fully utilize a hard X-ray source generated by a 5-Tesla superconducting wavelength shifter (SWLS) that shifts the critical energy of synchrotron spectrum from 2.1 to 7.5 keV, we have designed and constructed three hard X-ray beamlines, BL01A, BL01B, and BL0IC. BL01A is a white light beamline for phase-contrast X-ray image applications. The spatial resolution of phase-contrast X-ray image is 1 {mu}m. The photon flux can saturate a camera of 700-microns field-of-view within 10 ms. BL01B equipped with a double crystal monochromator (DCM) and a toroidal focusing mirror, which provides photon beams with energies from 5 to 20 keV, is adequate for scattering related experiments and hard X-ray microscopy. The energy-resolution {delta}E/E is 1 x 10-3. The photon flux is optimized to be 4.5 x 1011 photons s-1 with 200 mA ring current, which outcasts the flux of the wiggler beamline BL17B by 110 times at 15 keV. BL01C equipped with a DCM and both collimating and focusing mirrors, covering photon energies from 6 to 33 keV, is ideal for EXAFS and X-ray diffraction (XRD) experiments. The average photon flux is 3 x 1010 photons s-1 with 200 mA ring current. The energy-resolution is between 1.7 x 10-4 and 3.0 x 10-4. In this article, we will present the measured performance of these beamlines.

  15. Toward steering a jet of particles into an x-ray beam with optically induced forces

    NASA Astrophysics Data System (ADS)

    Eckerskorn, Niko; Bowman, Richard; Kirian, Richard A.; Awel, Salah; Wiedorn, Max; Küpper, Jochen; Padgett, Miles J.; Chapman, Henry N.; Rode, Andrei V.

    2015-08-01

    Optical trapping of light-absorbing particles in a gaseous environment is governed by a laser-induced photophoretic force, which can be orders of magnitude stronger than the force of radiation pressure induced by the same light intensity. In spite of many experimental studies, the exact theoretical background underlying the photophoretic force and the prediction of its influence on the particle motion is still in its infancy. Here, we report the results of a quantitative analysis of the photophoretic force and the stiffness of trapping achieved by levitating graphite and carbon-coated glass shells of calibrated sizes in an upright diverging hollow-core vortex beam, which we refer to as an `optical funnel'. The measurements of forces were conducted in air at various gas pressures in the range from 5 mbar to 2 bar. The results of these measurements lay the foundation for developing a touch-free optical system for precisely positioning sub-micrometer bioparticles at the focal spot of an x-ray free electron laser, which would significantly enhance the efficiency of studying nanoscale morphology of proteins and biomolecules in femtosecond coherent diffractive imaging experiments.

  16. Kinetic effects and nonlinear heating in intense x-ray-laser-produced carbon plasmas

    NASA Astrophysics Data System (ADS)

    Sentoku, Y.; Paraschiv, I.; Royle, R.; Mancini, R. C.; Johzaki, T.

    2014-11-01

    The x-ray laser-matter interaction for a low-Z material, carbon, is studied with a particle-in-cell code that solves the photoionization and x-ray transport self-consistently. Photoionization is the dominant absorption mechanism and nonthermal photoelectrons are produced with energy near the x-ray photon energy. The photoelectrons ionize the target rapidly via collisional impact ionization and field ionization, producing a hot plasma column behind the laser pulse. The radial size of the heated region becomes larger than the laser spot size due to the kinetic nature of the photoelectrons. The plasma can have a temperature of more than 10 000 K (>1 eV ), an energy density greater than 104 J /cm3 , an ion-ion Coulomb coupling parameter ? ?1 , and electron degeneracy ? ?1 , i.e., strongly coupled warm dense matter. By increasing the laser intensity, the plasma temperature rises nonlinearly from tens of eV to hundreds of eV, bringing it into the high energy density matter regime. The heating depth and temperature are also controllable by changing the photon energy of the incident laser light.

  17. Time response of a type IIa natural diamond photoconductor to long-pulse low-intensity soft x rays

    NASA Astrophysics Data System (ADS)

    Coleman, J. W.; Lierzer, J. R.; Petrasso, R. D.

    1995-01-01

    For the study of soft x rays from plasmas and laser-plasma interactions, type IIa diamond photoconductor detector (PCD) is an important diagnostic for emissions from z pinches, [R. B. Spielman, Rev. Sci. Instrum. 63, 5056 (1992)], synchrotons, and laser-produced plasmas [D. R. Kania et al., Rev. Sci. Instrum. 61, 2765 (1990)]. Among diamond's advantages are its time response (in the picosecond-to-nanosecond range for high-intensity fast pulses of soft x rays [D. R. Kania et al., J. Appl. Phys. 68, 124 (1990)]), and its band gap of 5.45 eV (which reduces its visible and near-uv sensitivity to near zero). We have investigated type IIa PCD using low-intensity slow pulses generated by a pulsed e beam hitting a copper target, with repetitions up to 50 kHz. The time response in this case is presented, leading to a proposal for a new type of diamond PCD for tokamaks, where the single detector has an array capability for position sensing and energy analysis.

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

    SciTech Connect

    Gmuer, N.F.; White-DePace, S.M.

    1987-08-01

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

  19. Resonant photo-pumping x-ray-laser scheme using intense characteristic x rays for water-window radiation generation

    SciTech Connect

    Kawachi, Tetsuya; Kato, Yoshiaki

    2011-12-15

    A line pair for a resonant photo-pumping x-ray-laser scheme is proposed in which the wavelength matching between the aluminum K{alpha}{sub 2} line ({lambda}= 0.833 95 nm) and the 2p{sup 6}-(2p{sub 1/2},4d{sub 3/2}){sub 1} transition of the neonlike zinc ions ({lambda}= 0.834 00 nm) is used. The population kinetics code of the neonlike zinc ions in plasma under irradiation of the aluminum K{alpha} line shows that substantial amplification gain can be generated in the transition of (2p{sub 1/2},3p{sub 1/2}){sub 0}-(2p{sub 1/2},4d{sub 3/2}){sub 1} at a wavelength of 3.5 nm. We also investigate the experimental arrangement of this scheme, which implies that this scheme is feasible with the present ultra-short-pulse-laser technology.

  20. Flash X-Ray (FXR) Accelerator Optimization - Beam-induced Voltage Simulation and TDR Measurements

    SciTech Connect

    Ong, M M; Vogtlin, G E

    2004-04-07

    Lawrence Livermore National Laboratory (LLNL) is evaluating design alternatives to improve the voltage regulation in our Flash X-Ray (FXR) accelerator cell and pulse-power system. The goal is to create a more mono-energetic electron beam that will create an x-ray source with a smaller spot-size. Studying the interaction of the beam and accelerator cell will generate improved designs for high-current accelerators at Livermore and elsewhere. When an electron beam crosses the energized gap of an accelerator cell, the electron energy is increased. However, the beam with the associated electromagnetic wave also looses a small amount of energy because of the increased impedance seen across the gap. The phenomenon is sometimes called beam loading. It can also be described as a beam-induced voltage at the gap which is time varying. This creates beam energy variations that we need to understand and control. A high-fidelity computer simulation of the beam and cell interaction has been completed to quantify the time varying induced voltage at the gap. The cell and pulse-power system was characterized using a Time-domain Reflectometry (TDR) measurement technique with a coaxial air-line to drive the cell gap. The beam-induced cell voltage is computed by convoluting the cell impedance with measured beam current. The voltage was checked against other measurements to validate the accuracy. The simulation results predicted that there are significant beam-induced gap voltage variations. Beam-induced voltages from different current profiles and cell impedances were simulated and compared. This allows us to predict the effect on voltage regulation for different design alternatives before making hardware changes and high-voltage testing. The beam-induced voltages are incorporated into a larger accelerator system-model to quantify their effect on total beam energy variations.

  1. Hard x-ray or gamma ray laser by a dense electron beam

    SciTech Connect

    Son, S.; Joon Moon, Sung

    2012-06-15

    A dense electron beam propagating through a laser undulator can radiate a coherent x-ray or gamma ray. This lasing scheme is studied with the Landau damping theory. The analysis suggests that, with currently available physical parameters, coherent gamma rays of up to 50 keV can be generated. The electron quantum diffraction suppresses the free electron laser action, which limits the maximum radiation.

  2. High gain, Fast Scan, Broad Spectrum Parallel Beam Wavelength Dispersive X-ray Spectrometer for SEM

    SciTech Connect

    OHara, David

    2009-05-08

    During contract # DE-FG02-ER83545, Parallax Research, Inc. developed a High gain, Fast Scan Broad Spectrum Parallel beam Wavelength Dispersive X-ray Spectrometer for use on Scanning Electron Microscopes (SEM). This new spectrometer allows very fast high resolution elemental analysis of samples in an electron microscope. By comparison to previous WDS spectrometers, it can change from one energy position to another very quickly and has an extended range compared to some similar products.

  3. Interaction of high intensity laser with non-uniform clusters and enhanced X-ray emission

    SciTech Connect

    Liu, C. S.; Tripathi, V. K.; Kumar, Manoj

    2014-10-15

    Laser irradiated clusters with non-uniform density variation are shown to broaden surface plasmon resonance very significantly. As the clusters get heated and expand hydro-dynamically, the Bremsstrahlung X-ray emission yield passes through a maximum in time. The maximum yield decreases with increase in non-uniformity in the electron density inside the clusters. At higher laser intensity, the nonlinearity in laser cluster interaction may arise even prior to electron heating, via the relativistic mass variation and the nonlinear restoration force on electrons. For clusters with radius less than one tenth of the laser wavelength, the restoration force nonlinearity dominates.

  4. A Positional X-ray Instrumentation Test Stand For Beam-Line Experiments

    NASA Astrophysics Data System (ADS)

    Nikoleyczik, Jonathan; Prieskorn, Z.; Burrows, D. N.; Falcone, A.

    2014-01-01

    A multi-axis, motion controlled test stand has been built in the PSU 47 m X-ray beam-line for the purpose of testing X-ray instrumentation and mirrors using parallel rays. The test stand is capable of translation along two axes and rotation about two axes with motorized fine position control. The translation stages have a range of motion of 200 mm with a movement accuracy of ± 2.5 microns. Rotation is accomplished with a two-axis gimbal which can rotate 360° about one axis and 240° about another; movement with ± 35 arcsecond accuracy are achieved in both axes. The position and status are monitored using a LabView program. An XCalibr source with multiple target materials is used as an X-ray source and can produce multiple lines between 0.8 and 8 keV. Some sample spectra are shown from a Si-PIN diode detector. This system is well suited for testing X-ray mirror segments which are currently being developed.

  5. Monte Carlo Simulation of the Conversion X-Rays from the Electron Beam of PFMA-3

    SciTech Connect

    Ceccolini, E.; Mostacci, D.; Sumini, M.; Rocchi, F.; Tartari, A.

    2011-12-13

    PFMA-3, a dense Plasma Focus device, is being optimized as an X-ray generator. X-rays are obtained from the conversion of the electron beam emitted in the backward direction and driven to impinge on a 50 {mu}m brass foil. Monte Carlo simulations of the X-ray emission have been conducted with MCNPX. The electron spectrum had been determined experimentally and is used in the present work as input to the simulations. Dose to the brass foil has been determined both from simulations and from measurements with a thermographic camera, and the two results are found in excellent agreement, thus validating further the electron spectrum assumed as well as the simulation set-up. X-ray emission has been predicted both from bremsstrahlung and from characteristic lines. The spectrum has been found to be comprised of two components of which the one at higher energy, 30 divide 70 keV, is most useful for IORT applications. The results are necessary to estimate penetration in and dose to Standard Human Tissue.

  6. Imaging single cells in a beam of live cyanobacteria with an X-ray laser.

    PubMed

    van der Schot, Gijs; Svenda, Martin; Maia, Filipe R N C; Hantke, Max; DePonte, Daniel P; Seibert, M Marvin; Aquila, Andrew; Schulz, Joachim; Kirian, Richard; Liang, Mengning; Stellato, Francesco; Iwan, Bianca; Andreasson, Jakob; Timneanu, Nicusor; Westphal, Daniel; Almeida, F Nunes; Odic, Dusko; Hasse, Dirk; Carlsson, Gunilla H; Larsson, Daniel S D; Barty, Anton; Martin, Andrew V; Schorb, Sebastian; Bostedt, Christoph; Bozek, John D; Rolles, Daniel; Rudenko, Artem; Epp, Sascha; Foucar, Lutz; Rudek, Benedikt; Hartmann, Robert; Kimmel, Nils; Holl, Peter; Englert, Lars; Duane Loh, Ne-Te; Chapman, Henry N; Andersson, Inger; Hajdu, Janos; Ekeberg, Tomas

    2015-01-01

    There exists a conspicuous gap of knowledge about the organization of life at mesoscopic levels. Ultra-fast coherent diffractive imaging with X-ray free-electron lasers can probe structures at the relevant length scales and may reach sub-nanometer resolution on micron-sized living cells. Here we show that we can introduce a beam of aerosolised cyanobacteria into the focus of the Linac Coherent Light Source and record diffraction patterns from individual living cells at very low noise levels and at high hit ratios. We obtain two-dimensional projection images directly from the diffraction patterns, and present the results as synthetic X-ray Nomarski images calculated from the complex-valued reconstructions. We further demonstrate that it is possible to record diffraction data to nanometer resolution on live cells with X-ray lasers. Extension to sub-nanometer resolution is within reach, although improvements in pulse parameters and X-ray area detectors will be necessary to unlock this potential. PMID:25669616

  7. Temperature- and energy-dependent phase shifts of resonant multiple-beam X-ray diffraction in germanium crystals.

    PubMed

    Liao, Po-Yu; Liu, Wen-Chung; Cheng, Chih-Hao; Chiu, Yi-Hua; Kung, Ying-Yu; Chang, Shih-Lin

    2015-07-01

    This paper reports temperature- and energy-dependent phase shifts of resonant multiple-beam X-ray diffraction in germanium crystals, involving forbidden (002) and weak (222) reflections. Phase determination based on multiple-beam diffraction is employed to estimate phase shifts from (002)-based {(002)(375)(373?)} four-beam cases and (222)-based { (222)(5?33?)} three-beam cases in the vicinity of the Ge K edge for temperatures from 20?K up to 300?K. The forbidden/weak reflections enhance the sensitivity of measuring phases at resonance. At room temperature, the resonance triplet phases reach a maximum of 8 for the four-beam cases and -19 for the three-beam cases. It is found that the peak intensities and triplet phases obtained from the (002) four-beam diffraction are related to thermal motion induced anisotropy and anomalous dispersion, while the (222) three-beam diffraction depends on the aspherical covalent electron distribution and anomalous dispersion. However, the electron-phonon interaction usually affects the forbidden reflections with increasing temperatures and seems to have less effect on the resonance triplet phase shifts measured from the (002) four-beam diffraction. The resonance triplet phase shifts of the (222) three-beam diffraction versus temperature are also small. PMID:26131901

  8. On the scaling of multicrystal data sets collected at high-intensity X-ray and electron sources

    PubMed Central

    Coppens, Philip; Fournier, Bertrand

    2015-01-01

    The need for data-scaling has become increasingly evident as time-resolved pump-probe photocrystallography is rapidly developing at high intensity X-ray sources. Several aspects of the scaling of data sets collected at synchrotrons, XFELs (X-ray Free Electron Lasers) and high-intensity pulsed electron sources are discussed. They include laser-ON/laser-OFF data scaling, inter- and intra-data set scaling. PMID:26798829

  9. Design and characterization of electron beam focusing for X-ray generation in novel medical imaging architecturea

    PubMed Central

    Bogdan Neculaes, V.; Zou, Yun; Zavodszky, Peter; Inzinna, Louis; Zhang, Xi; Conway, Kenneth; Caiafa, Antonio; Frutschy, Kristopher; Waters, William; De Man, Bruno

    2014-01-01

    A novel electron beam focusing scheme for medical X-ray sources is described in this paper. Most vacuum based medical X-ray sources today employ a tungsten filament operated in temperature limited regime, with electrostatic focusing tabs for limited range beam optics. This paper presents the electron beam optics designed for the first distributed X-ray source in the world for Computed Tomography (CT) applications. This distributed source includes 32 electron beamlets in a common vacuum chamber, with 32 circular dispenser cathodes operated in space charge limited regime, where the initial circular beam is transformed into an elliptical beam before being collected at the anode. The electron beam optics designed and validated here are at the heart of the first Inverse Geometry CT system, with potential benefits in terms of improved image quality and dramatic X-ray dose reduction for the patient. PMID:24826066

  10. Design and characterization of electron beam focusing for X-ray generation in novel medical imaging architecturea)

    NASA Astrophysics Data System (ADS)

    Bogdan Neculaes, V.; Zou, Yun; Zavodszky, Peter; Inzinna, Louis; Zhang, Xi; Conway, Kenneth; Caiafa, Antonio; Frutschy, Kristopher; Waters, William; De Man, Bruno

    2014-05-01

    A novel electron beam focusing scheme for medical X-ray sources is described in this paper. Most vacuum based medical X-ray sources today employ a tungsten filament operated in temperature limited regime, with electrostatic focusing tabs for limited range beam optics. This paper presents the electron beam optics designed for the first distributed X-ray source in the world for Computed Tomography (CT) applications. This distributed source includes 32 electron beamlets in a common vacuum chamber, with 32 circular dispenser cathodes operated in space charge limited regime, where the initial circular beam is transformed into an elliptical beam before being collected at the anode. The electron beam optics designed and validated here are at the heart of the first Inverse Geometry CT system, with potential benefits in terms of improved image quality and dramatic X-ray dose reduction for the patient.

  11. Design and characterization of electron beam focusing for X-ray generation in novel medical imaging architecture

    SciTech Connect

    Bogdan Neculaes, V. Zou, Yun; Zavodszky, Peter; Inzinna, Louis; Zhang, Xi; Conway, Kenneth; Caiafa, Antonio; Frutschy, Kristopher; Waters, William; De Man, Bruno

    2014-05-15

    A novel electron beam focusing scheme for medical X-ray sources is described in this paper. Most vacuum based medical X-ray sources today employ a tungsten filament operated in temperature limited regime, with electrostatic focusing tabs for limited range beam optics. This paper presents the electron beam optics designed for the first distributed X-ray source in the world for Computed Tomography (CT) applications. This distributed source includes 32 electron beamlets in a common vacuum chamber, with 32 circular dispenser cathodes operated in space charge limited regime, where the initial circular beam is transformed into an elliptical beam before being collected at the anode. The electron beam optics designed and validated here are at the heart of the first Inverse Geometry CT system, with potential benefits in terms of improved image quality and dramatic X-ray dose reduction for the patient.

  12. Wide-band, high-resolution soft x-ray spectrometer for the Electron Beam Ion Trap

    SciTech Connect

    Brown, G.V.; Beiersdorfer, P.; Widmann, K.

    1999-01-01

    We have constructed two wide-band, high-resolution vacuum flat crystal spectrometers and implemented them on the Electron Beam Ion Trap located at the Lawrence Livermore National Laboratory. Working in unison, these spectrometers can measure an x-ray bandwidth {le}9 {Angstrom} in the soft x-ray region below 21 {Angstrom}. In order to achieve this large bandwidth each spectrometer houses either two 125 mm {times} 13 mm {times} 2 mm RAP (rubidium acid phthalate, 2d=26.121 {Angstrom}), two 114 mm {times} 13 mm {times} 2 mm TlAP (thallium acid phthalate, 2d=25.75 {Angstrom}) crystals, or some combination thereof, for dispersion and two position sensitive proportional counters for detection of x rays. The spectrometers are used to measure wavelengths and relative intensities of the L-shell line emission from FethinspXVII{endash}XXIV for comparison with spectra obtained from astrophysical and laboratory plasmas. The wide wavelength coverage attainable by these spectrometers makes it possible to measure all the L-shell emission from a given iron ion species simultaneously. {copyright} {ital 1999 American Institute of Physics.}

  13. SOLAR HARD X-RAY SOURCE SIZES IN A BEAM-HEATED AND IONIZED CHROMOSPHERE

    SciTech Connect

    O'Flannagain, Aidan M.; Gallagher, Peter T.; Brown, John C.

    2015-02-01

    Solar flare hard X-rays (HXRs) are produced as bremsstrahlung when an accelerated population of electrons interacts with the dense chromospheric plasma. HXR observations presented by Kontar et al. using the Ramaty High-Energy Solar Spectroscopic Imager have shown that HXR source sizes are three to six times more extended in height than those predicted by the standard collisional thick target model (CTTM). Several possible explanations have been put forward including the multi-threaded nature of flare loops, pitch-angle scattering, and magnetic mirroring. However, the nonuniform ionization (NUI) structure along the path of the electron beam has not been fully explored as a solution to this problem. Ionized plasma is known to be less effective at producing nonthermal bremsstrahlung HXRs when compared to neutral plasma. If the peak HXR emission was produced in a locally ionized region within the chromosphere, the intensity of emission will be preferentially reduced around this peak, resulting in a more extended source. Due to this effect, along with the associated density enhancement in the upper chromosphere, injection of a beam of electrons into a partially ionized plasma should result in an HXR source that is substantially more vertically extended relative to that for a neutral target. Here we present the results of a modification to the CTTM, which takes into account both a localized form of chromospheric NUI and an increased target density. We find 50 keV HXR source widths, with and without the inclusion of a locally ionized region, of ∼3 Mm and ∼0.7 Mm, respectively. This helps to provide a theoretical solution to the currently open question of overly extended HXR sources.

  14. Optical and x-ray imaging of electron beams using synchrotron emission

    SciTech Connect

    Wilke, M.D.

    1994-12-01

    In the case of very low eniittance electron and positron storage ring beams, it is impossible to make intrusive measurements of beam properties without increasing the emittance and possibly disrupting the beam. In cases where electron or positron beams have high average power densities (such as free electron laser linacs), intrusive probes such as wires and optical transition radiation screens or Cherenkov emitting screens can be easily damaged or destroyed. The optical and x-ray emissions from the bends in the storage rings and often from linac bending magnets can be used to image the beam profile to obtain emittance information about the beam. The techniques, advantages and limitations of using both optical and x-ray synchrotron emission to measure beam properties are discussed and the possibility of single bunch imaging is considered. The properties of suitable imagers and converters such as phosphors are described. Examples of previous, existing and planned applications are given where available, including a pinhole imaging system currently being designed for the Advanced Photon Source at Argonne National Laboratory.

  15. Optical and x-ray imaging of electron beams using synchrotron emission

    SciTech Connect

    Wilke, M.

    1995-01-01

    In the case of very low emittance electron and positron storage ring beams, it is impossible to make intrusive measurements of beam properties without increasing the emittance and possibly disrupting the beam. In cases where electron or positron beams have high average power densities (such as free electron laser linacs), intrusive probes such as wires and optical transition radiation screens or Cherenkov emitting screens can be easily damaged or destroyed. The optical and x-ray emissions from the bends in the storage rings and often from linac bending magnets can be used to image the beam profile to obtain emittance information about the beam. The techniques, advantages and limitations of using both optical and x-ray synchrotron emission to measure beam properties are discussed and the possibility of single bunch imaging is considered. The properties of suitable imagers and converters such as phosphors are described. Examples of previous, existing and planned applications are given where available, including a pinhole imaging system currently being designed for the Advanced Photon Source at Argonne National Laboratory.

  16. EBT2 dosimetry of x-rays produced by the electron beam from a Plasma Focus for medical applications

    SciTech Connect

    Ceccolini, E.; Mostacci, D.; Sumini, M.; Rocchi, F.; Tartari, A.; Mariotti, F.

    2012-09-01

    The electron beam emitted from the back of Plasma Focus devices is being studied as a radiation source for intraoperative radiation therapy applications. A Plasma Focus device is being developed to this aim, to be utilized as an x-ray source. The electron beam is driven to impinge on 50 {mu}m brass foil, where conversion x-rays are generated. Measurements with gafchromic film are performed to analyse the attenuation of the x-rays beam and to predict the dose given to the culture cell in radiobiological experiments to follow.

  17. Common features of particle beams and x-rays generated in a low energy dense plasma focus device

    SciTech Connect

    Behbahani, R. A.; Xiao, C.

    2015-02-15

    Features of energetic charged particle beams and x-ray emission in a low energy (1–2 kJ) plasma focus (DPF) device are described and the possible mechanism are explained based on circuit analyses and energy balance in the DPF system. In particular, the resistance and the voltage across the plasma column are estimated to explain the mechanisms of the generation of particle beams and hard x-ray. The analysis shows that the total inductance of a DPF might have played a role for enhancement of the particle beams and x-ray emissions during the phase of anomalous resistance.

  18. Common features of particle beams and x-rays generated in a low energy dense plasma focus device

    NASA Astrophysics Data System (ADS)

    Behbahani, R. A.; Xiao, C.

    2015-02-01

    Features of energetic charged particle beams and x-ray emission in a low energy (1-2 kJ) plasma focus (DPF) device are described and the possible mechanism are explained based on circuit analyses and energy balance in the DPF system. In particular, the resistance and the voltage across the plasma column are estimated to explain the mechanisms of the generation of particle beams and hard x-ray. The analysis shows that the total inductance of a DPF might have played a role for enhancement of the particle beams and x-ray emissions during the phase of anomalous resistance.

  19. Combined X-ray fluorescence and absorption computed tomography using a synchrotron beam

    NASA Astrophysics Data System (ADS)

    Hall, C.

    2013-06-01

    X-ray computed tomography (CT) and fluorescence X-ray computed tomography (FXCT) using synchrotron sources are both useful tools in biomedical imaging research. Synchrotron CT (SRCT) in its various forms is considered an important technique for biomedical imaging since the phase coherence of SR beams can be exploited to obtain images with high contrast resolution. Using a synchrotron as the source for FXCT ensures a fluorescence signal that is optimally detectable by exploiting the beam monochromaticity and polarisation. The ability to combine these techniques so that SRCT and FXCT images are collected simultaneously, would bring distinct benefits to certain biomedical experiments. Simultaneous image acquisition would alleviate some of the registration difficulties which comes from collecting separate data, and it would provide increased information about the sample: functional X-ray images from the FXCT, with the morphological information from the SRCT. A method is presented for generating simultaneous SRCT and FXCT images. Proof of principle modelling has been used to show that it is possible to recover a fluorescence image of a point-like source from an SRCT apparatus by suitably modulating the illuminating planar X-ray beam. The projection image can be successfully used for reconstruction by removing the static modulation from the sinogram in the normal flat and dark field processing. Detection of the modulated fluorescence signal using an energy resolving detector allows the position of a fluorescent marker to be obtained using inverse reconstruction techniques. A discussion is made of particular reconstruction methods which might be applied by utilising both the CT and FXCT data.

  20. Supershort avalanche electron beams and x-ray in high-pressure nanosecond discharges

    NASA Astrophysics Data System (ADS)

    Tarasenko, V.

    2008-07-01

    Since 2003, an interest to investigation of e-beams generation in gas-filled diodes with high pressures has been rekindled. In 2005, the advanced recording methods of electron beams and the use of digital oscilloscopes with wide bandwidth provided the measurements of the beam current duration with time resolution of sim 100 ps. In this paper, the recent measurement results on duration and amplitude of a beam, generated at a nanosecond discharge in different gases have been summarized (Tarasenko et al. 2005, Baksht et al. 2007, Tarasenko et al. 2008). Voltage pulses sim 25, sim 150 and sim 250 kV in amplitude were applied to the gas gap with inhomogeneous electric field. It is presented that the current of supershort avalanche electrons beam (SAEB) recording through a area with a small diameter the pulse duration behind a foil from the gas diode with air at atmospheric pressure is no more than 90 ps. For recording, the pulse shape it is necessary to use a small-sized coaxial collector, loaded to a high-frequency cable, and the same collector is used for taking the charge density distribution over the foil surface in order to determine the SAEB amplitude. The electron distribution over the foil section should be compared with a per pulse distribution. In these experiments, we have compared the distributions obtained per pulse on a RF-3 and luminophore films, placed behind a foil. Besides that, intensity distribution of X-ray radiation at the gas diode output was recorded by using a multi-channel detection device based on microstrip arsenide-gallium detectors of ionizing radiation. An analysis of those data shows that at the beam current duration (FWHM) of sim 90 ps the beam current amplitude behind the 10- mu m thickness Al-foil at atmospheric pressure of air is sim 50 A. Discharge formation and SAEB generation in sulfur hexafluoride and xenon at pressure of 0.01-2.5 atm and helium of 10^-4 - 12 atm have been investigated. The beam of runaway electrons behind 45 mu m Al-Be foil was observed at sulfur hexafluoride and xenon pressure up to 2 atm. It was found that the SAEB duration (FWHM) increased with sulfur hexafluoride pressure in the range 1-2 atm. Spectra of a diffuse and contracted discharges in sulfur hexafluoride are presented. Waveforms of the electrons beams generated in helium at pressure 10^-4 - 12 atm were registered. Therewith the electrons beam in helium at p = 12 atm was obtained for the first time. Complex dependence of the electrons beam current amplitude from helium pressure was obtained. Three peaks of the current were observed at pressure 0.01, sim 0.07 and sim 3 atm.

  1. Chemical effects on the K?/K? X-ray intensity ratios of Mn, Ni and Cu complexes

    NASA Astrophysics Data System (ADS)

    evik, U.; De?irmencio?lu, I.; Ertu?ral, B.; Apayd?n, G.; Balta?, H.

    2005-10-01

    Chemical effects on the K?/K? X-ray intensity ratios for some Mn, Ni, and Cu complexes of a new schiff-base with salen N2H2 type were investigated. The samples were excited by 59.543 keV ?-rays from a 241Am annular radioactive source. K X-rays emitted by samples were counted by a Si(Li) detector with resolution 157 eV at 5.9 keV. We observed the chemical effect on the K?/K? X-ray intensity ratios for Mn, Ni and Cu complexes. The experimental results showed that the K?/K? X-ray intensity ratios for compounds with complexes are generally larger than those with salt form. The experimental values have been compared with the other experimental and the theoretically calculated values of pure elements. The results are in very good agreement with the others.

  2. Optimization for Single-Spike X-Ray FELs at LCLS with a Low Charge Beam

    SciTech Connect

    Wang, L.; Ding, Y.; Huang, Z.; /SLAC

    2011-12-14

    The Linac Coherent Light Source is an x-ray free-electron laser at the SLAC National Accelerator Laboratory, which is operating at x-ray wavelengths of 20-1.2 Angstrom with peak brightness nearly ten orders of magnitude beyond conventional synchrotron radiation sources. At the low charge operation mode (20 pC), the x-ray pulse length can be <10 fs. In this paper we report our numerical optimization and simulations to produce even shorter x-ray pulses by optimizing the machine and undulator setup at 20 pC charge. In the soft x-ray regime, with combination of slotted-foil or undulator taper, a single spike x-ray pulse is achievable with peak FEL power of a few 10s GW. Linac Coherent Light Source (LCLS), the world's first hard x-ray Free electron laser (FEL), has started operation since 2009. With nominal operation charge of 250 pC, the generated x-ray pulse length is from 70 fs to a few hundred fs. This marks the beginning of a new era of ultrashort x-ray sciences. In addition, a low charge (20pC) operation mode has also been established. Since the collective effects are reduced at the low charge mode, we can increase the compression factor and still achieve a few kA peak current. The expected electron beam and x-ray pulses are less than 10 fs. There are growing interests in even shorter x-ray pulses, such as fs to sub-fs regime. One of the simple solutions is going to even lower charge. As discussed, single-spike x-ray pulses can be generated using 1 pC charge. However, this charge level is out of the present LCLS diagnostic range. 20 pC is a reasonable operation charge at LCLS, based on the present diagnostic system. At 20 pC in the soft x-ray wavelength regime, we have experimentally demonstrated that FEL can work at undercompression or over-compression mode, such as 1 degree off the full-compression; at full-compression, however, there is almost no lasing. In hard x-ray wavelength regime, we observed that there are reasonable photons generated even at full-compression mode, although the photon number is less than that from under-compression or over-compression mode. Since we cannot measure the x-ray pulse length at this time scale, the machine is typically optimized for generating maximum photons, not minimum pulse length. In this paper, we study the methods of producing femtosecond (or single-spike) x-ray pulses at LCLS with 20 pC charge, based on start-to-end simulations. Figure 1 shows a layout of LCLS. The compression in the second bunch compressor (BC2) determines the final e-beam bunch length. However, the laser heater, dog-leg after the main linac (DL2) and collective effects also affect the final bunch length. To adjust BC2 compression, we can either change the L2 phase or BC2 R{sub 56}. In this paper we only tune L2 phase while keep BC2 R{sub 56} fixed. For the start-to-end simulations, we used IMPACT-T and ELEGANT tracking from the photocathode to the entrance of the undulator, after that the FEL radiation was simulated with GENESIS. IMPACT-T tracks about 10{sup 6} particles in the injector part until 135 MeV, including 3D space charge force. The output particles from IMPACT-T are smoothed and increased to 12 x 10{sup 6} to reduce high-frequency numerical noise for subsequent ELEGANT simulations, which include linear and nonlinear transport effects, a 1D transient model of CSR, and longitudinal space charge effects, as well as geometric and resistive wake fields in the accelerator. In GENESIS part, the longitudinal wake field from undulator chamber and longitudinal space field are also included.

  3. Incident photon energy and Z dependence of L X-ray relative intensities

    SciTech Connect

    Kumar, Anil; Chauhan, Yogeshwar; Puri, Sanjiv

    2010-11-15

    The intensity ratios, I{sub Lk}/I{sub L{alpha}1} (k = l, {eta}, {alpha}{sub 2}, {beta}{sub 1}, {beta}{sub 2,15}, {beta}{sub 3}, {beta}{sub 4}, {beta}{sub 5,7}, {beta}{sub 6}, {beta}{sub 9,10}, {gamma}{sub 1,5}, {gamma}{sub 6,8}, {gamma}{sub 2,3}, {gamma}{sub 4}), have been evaluated for elements with atomic number 36 {<=} Z {<=} 92 at incident photon energies ranging E{sub L1} < E{sub inc} {<=} 200 keV using currently considered to be more reliable theoretical data sets of different physical parameters, namely, L{sub i} (i = 1-3) subshell photoionization cross sections based on the relativistic Hartree-Fock-Slater model, the X-ray emission rates based on the Dirac-Fock model, and the fluorescence and Coster-Kronig yields based on the Dirac-Hartree-Slater model. At incident photon energies above the K-shell ionization threshold, the contribution to the production of different L X-ray lines due to the additional L{sub i} (i = 1-3) subshell vacancies created following decay of the primary K-shell vacancies have also been included in the present calculations. The important features pertaining to dependence of the tabulated intensity ratios on the incident photon energy and atomic number have been discussed.

  4. A study of diagnostic x-ray lines in heliumlike neon using an electron beam ion trap

    SciTech Connect

    Wargelin, B.J.

    1993-10-01

    Heliumlike ions play an extremely important role in X-ray astrophysics because of their emissivity and because the relative intensities of their emission lines can be used to infer physical characteristics of X-ray emitting plasmas, including temperature, electron density, and ionization balance. In order to properly apply these diagnostics, accurate atomic data are required, including cross sections for collisional excitation and ionization, radiative rates, and the wavelengths and strengths of satellite lines. Although theoretical atomic models have been created to estimate many of the rates and cross sections involved, very few experimental results are available for comparison with theoretical predictions. This thesis describes an experimental study of heliumlike neon using an electron beam ion trap, a device specifically designed to study X-ray emission from highly charged ions. Using a low-energy X-ray spectrometer designed and built for this experiment, electron impact excitation cross sections and dielectronic satellite strengths were measured for all significant n = 2{yields}1 emission lines in He-like and Li-like Ne over a range of energy extending from well below the direct excitation threshold of the lines to over fourteen times the threshold energy. The cross section for innershell ionization of Li-like Ne, which excites the He-like forbidden line, was also measured. In addition, the radiative and collisional depopulation rates of the metastable ls2s {sup 3}S{sub 1}, state, which form the basis of the He-like Ne density diagnostic, were determined. Experimental results were generally in agreement with theoretical predictions, although some significant differences were noted, particularly for the wavelengths and resonance strengths of dielectronic satellites.

  5. Soft-x-ray spectra of highly charged Kr ions in an electron beam ion trap.

    PubMed

    Chen, H; Beiersdorfer, P; Fournier, K B; Träbert, E

    2002-05-01

    Systematic variation of the electron-beam energy in the EBIT-II electron beam ion trap has been employed to produce soft-x-ray spectra (20-75 A) of Kr with well-defined maximum charge states ranging from Cu- to Al-like ions. Guided by large-scale relativistic atomic structure calculations, the strongest lines have been identified with Delta n=1 (n=3 to n(')=4) transitions from Ni- to P-like ions (Kr(8+)-Kr(21+)), as well as a number of 3p-4d and 3d-5f transitions. PMID:12059709

  6. Circular grating interferometer for mapping transverse coherence area of X-ray beams

    SciTech Connect

    Shi, Xianbo Marathe, Shashidhara; Wojcik, Michael J.; Kujala, Naresh G.; Macrander, Albert T.; Assoufid, Lahsen

    2014-07-28

    A circular grating interferometer was used to map the transverse coherence area of an X-ray beam. Due to the radial symmetry of the circular grating, coherence lengths along all transverse directions were obtained simultaneously by measuring the visibility decay of interferograms recorded at different distances behind a single circular ?/2 phase grating. The technique is model-free and provides direct measurement of the complex coherence factor of the beam. The use of a circular grating also enables the unique capability of measuring the source shape profile. Sensitivity of this technique was demonstrated by detecting the small source tilt of a few degrees.

  7. Use of 10 MV spoiled x ray beam for treatment of head and neck tumors

    SciTech Connect

    Kubo, H.; Russell, M.D.; Wang, C.C.

    1982-10-01

    The employment of a 10 MV X ray beam for treatment of head and neck tumors has been investigated. A 1.2 cm thick beam spoiler positioned 7 cm from the patient surface was used to achive adequate dose to the superficial region. This technique provides at least 90% depth dose at 0.5 cm depth, which is clinically required for the treatment. For departments able to acquire only one megavoltage machine, the technique can provide an option to treat adequately both shallow as well as deep-seated tumors by choosing a high megavoltage machine; a low megavoltage machine cannot provide an equivalent option to treat deep-seated tumors.

  8. Use of 10 MV spoiled x ray beam for treatment of head and neck tumors

    SciTech Connect

    Kubo, H.; Russell, M.D.; Wang, C.C.

    1982-10-01

    The employment of a 10 MV X ray beam for treatment of head and neck tumors has been investigated. A 1.2 cm thick beam spoiler positioned 7 cm from the patient surface was used to achieve adequate dose to the superficial region. This technique provides at least 90% depth dose at 0.5 cm depth, which is clinically required for the treatment. For departments able to acquire only one megavoltage machine, the technique can provide an option to treat adequately both shallow as well as deep-seated tumors by choosing a high megavoltage machine: a low megavoltage machine cannot provide an equivalent option to treat deep-seated tumors.

  9. Heat transfer issues in high-heat-load synchrotron x-ray beams

    SciTech Connect

    Khounsary, A.M.; Mills, D.M.

    1994-09-01

    In this paper, a short description of the synchrotron radiation x-ray sources and the associated power loads is given, followed by a brief description of typical synchrotron components and their heat load. It is emphasized that the design goals for most of these components is to limit (a) temperature, (b) stresses, or (c) strains in the system. Each design calls for a different geometry, material selection, and cooling scheme. Cooling schemes that have been utilized so far are primarily single phase and include simple macrochannel cooling, microchannel cooling, contact cooling, pin-post cooling, porous-flow cooling, jet cooling, etc. Water, liquid metals, and various cryogenic coolants have been used. Because the trend in x-ray beam development is towards brighter (i.e., more powerful) beams and assuming that no radical changes in the design of x-ray generating machines occurs in the next few years, it is fair to state that the utilization of various effective cooling schemes and, in particular, two-phase flow (e.g., subcooled boiling) warrants further investigation. This, however, requires a thorough examination of stability and reliability of two-phase flows for high-heat-flux components operating in ultrahigh vacuum with stringent reliability requirements.

  10. Soft X-Ray Magnetic Imaging of Focused Ion Beam Lithographically Patterned Fe Thin Films

    SciTech Connect

    Cook, Paul J.; Shen, Tichan H.; Grundy, PhilJ.; Im, Mi Young; Fischer, Peter; Morton, Simon A.; Kilcoyne, Arthur D.L.

    2008-11-09

    We illustrate the potential of modifying the magnetic behavior and structural properties of ferromagnetic thin films using focused ion beam 'direct-write' lithography. Patterns inspired by the split-ring resonators often used as components in meta-materials were defined upon 15 nm Fe films using a 30 keV Ga{sup +} focused ion beam at a dose of 2 x 10{sup 16} ions cm{sup -2}. Structural, chemical and magnetic changes to the Fe were studied using transmission soft X-ray microscopy at the ALS, Berkeley CA. X-ray absorption spectra showed a 23% reduction in the thickness of the film in the Ga irradiated areas, but no change to the chemical environment of Fe was evident. X-ray images of the magnetic reversal process show domain wall pinning around the implanted areas, resulting in an overall increase in the coercivity of the film. Transmission electron microscopy showed significant grain growth in the implanted regions.

  11. Model-based inspection of multipackage food products using a twin-beam x-ray system

    NASA Astrophysics Data System (ADS)

    Palmer, Stephen C.; Batchelor, Bruce G.

    1998-10-01

    A twin-orthogonal-fanbeam x-ray system has been built as part of a six-partner project funded by the Commission of the European Union. The images created by this system represent plan and side views of the object to be inspected. Using such a system, it is possible to locate a point-like feature that creates a significant shadow in both beams, in a 3D space. However, the real value of such a system lies in the fact that it is often possible to see a foreign body, such as a small piece of loose glass, within a jar using one beam, when the same contaminant is invisible to the other beam. Such a situation typically arises when the foreign body is obscured by the x-ray shadow of the neck-shoulder region of a jar. The x-ray system built by our colleagues in this consortium is being used to examine, simultaneously, six jars of semi-fluid savory sauce, held together by shrink-wrapping on a cardboard tray. The inspection algorithm consists of fitting multi-part models of the image intensity function to both the plan and side-view images. Once a model has been fitted, it is possible to use image comparison, in order to highlight any foreign bodies. The pre-processed plan and side-view images are analyzed and correlated together, so that in many cases, a foreign body whose view is obscured in one image can be detected in the other.

  12. Infrared Candidates for the Intense Galactic X-Ray Source GX 17+2

    NASA Astrophysics Data System (ADS)

    Deutsch, Eric W.; Margon, Bruce; Anderson, Scott F.; Wachter, Stefanie; Goss, W. M.

    1999-10-01

    We present new astrometric solutions and infrared Hubble Space Telescope observations of GX 17+2 (X1813-140), one of the brightest X-ray sources on the celestial sphere. Despite 30 years of intensive study and the existence of a strong radio counterpart with a subarcsecond position, the object remains optically unidentified. The observed X-ray characteristics strongly suggest that it is a so-called Z source, the rare but important category that includes Sco X-1 and Cyg X-2. Use of the USNO-A2.0 catalog enables us to measure the position of optical and infrared objects near the radio source to subarcsecond precision within the International Celestial Reference Frame for direct comparison with the radio position, which we also recompute using modern calibrators. With high confidence we eliminate the V~17.5 star NP Ser, often listed as the probable optical counterpart of the X-ray source, as a candidate. Our HST NICMOS observations show two faint objects within our 0.5" radius 90% confidence error circle. Even the brighter of the two, star A, is far fainter than expected (H~19.8), given multiple estimates of the extinction in this field and our previous understanding of Z sources, but it becomes the best candidate for the counterpart of GX 17+2. The probability of a chance coincidence of an unrelated faint object on the radio position is high. However, if the true counterpart is not star A, it is fainter still, and our conclusion that the optical counterpart is surprisingly underluminous is but strengthened. Based on observations with the Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  13. Beam hardening effects in grating-based x-ray phase-contrast imaging

    SciTech Connect

    Chabior, Michael; Donath, Tilman; David, Christian; Bunk, Oliver; Schuster, Manfred; Schroer, Christian; Pfeiffer, Franz

    2011-03-15

    Purpose: In this work, the authors investigate how beam hardening affects the image formation in x-ray phase-contrast imaging and consecutively develop a correction algorithm based on the results of the analysis. Methods: The authors' approach utilizes a recently developed x-ray imaging technique using a grating interferometer capable of visualizing the differential phase shift of a wave front traversing an object. An analytical description of beam hardening is given, highlighting differences between attenuation and phase-contrast imaging. The authors present exemplary beam hardening artifacts for a number of well-defined samples in measurements at a compact laboratory setup using a polychromatic source. Results: Despite the differences in image formation, the authors show that beam hardening leads to a similar reduction of image quality in phase-contrast imaging as in conventional attenuation-contrast imaging. Additionally, the authors demonstrate that for homogeneous objects, beam hardening artifacts can be corrected by a linearization technique, applicable to all kinds of phase-contrast methods using polychromatic sources. Conclusions: The evaluated correction algorithm is shown to yield good results for a number of simple test objects and can thus be advocated in medical imaging and nondestructive testing.

  14. Effects of electron beam dynamics on resolution of X-ray radiography

    NASA Astrophysics Data System (ADS)

    Christenson, P. J.; Kwan, T. J. T.

    2000-10-01

    In this study we link particle in cell (PIC) calculations from the code, MERLIN, with electron-photon Monte Carlo calculations using the code, MCNP, to produce synthetic radiographs. The results are used to examine several factors that may have an effect on the resolution of dynamic x-ray radiography such as done at the DARHT (Dual Axis Radiographic Hydro-Test) facility. Three properties are varied in this study, and the results of those variations are examined. First, the electron beam rise time from the accelerator is altered, and the difference on the temporal x-ray production is examined as well as the overall effects on the resolution of the radiographic image. Next, the effects of thermal velocity and energy spread of the electron beam as it exits the accelerator are studied by varying from a cold beam to a more realistic beam that fits with the expected or measured DARHT beam parameters. Finally, the bremsstrahlung conversion target composition is varied, and the effects of target materials and configurations are examined.

  15. Systems and methods for detecting an image of an object using multi-beam imaging from an X-ray beam having a polychromatic distribution

    DOEpatents

    Parham, Christopher A; Zhong, Zhong; Pisano, Etta; Connor, Jr., Dean M

    2015-03-03

    Systems and methods for detecting an image of an object using a multi-beam imaging system from an x-ray beam having a polychromatic energy distribution are disclosed. According to one aspect, a method can include generating a first X-ray beam having a polychromatic energy distribution. Further, the method can include positioning a plurality of monochromator crystals in a predetermined position to directly intercept the first X-ray beam such that a plurality of second X-ray beams having predetermined energy levels are produced. Further, an object can be positioned in the path of the second X-ray beams for transmission of the second X-ray beams through the object and emission from the object as transmitted X-ray beams. The transmitted X-ray beams can each be directed at an angle of incidence upon one or more crystal analyzers. Further, an image of the object can be detected from the beams diffracted from the analyzer crystals.

  16. Intensity distribution of the x ray source for the AXAF VETA-I mirror test

    NASA Technical Reports Server (NTRS)

    Zhao, Ping; Kellogg, Edwin M.; Schwartz, Daniel A.; Shao, Yibo; Fulton, M. Ann

    1992-01-01

    The X-ray generator for the AXAF VETA-I mirror test is an electron impact X-ray source with various anode materials. The source sizes of different anodes and their intensity distributions were measured with a pinhole camera before the VETA-I test. The pinhole camera consists of a 30 micrometers diameter pinhole for imaging the source and a Microchannel Plate Imaging Detector with 25 micrometers FWHM spatial resolution for detecting and recording the image. The camera has a magnification factor of 8.79, which enables measuring the detailed spatial structure of the source. The spot size, the intensity distribution, and the flux level of each source were measured with different operating parameters. During the VETA-I test, microscope pictures were taken for each used anode immediately after it was brought out of the source chamber. The source sizes and the intensity distribution structures are clearly shown in the pictures. They are compared and agree with the results from the pinhole camera measurements. This paper presents the results of the above measurements. The results show that under operating conditions characteristic of the VETA-I test, all the source sizes have a FWHM of less than 0.45 mm. For a source of this size at 528 meters away, the angular size to VETA is less than 0.17 arcsec which is small compared to the on ground VETA angular resolution (0.5 arcsec, required and 0.22 arcsec, measured). Even so, the results show the intensity distributions of the sources have complicated structures. These results were crucial for the VETA data analysis and for obtaining the on ground and predicted in orbit VETA Point Response Function.

  17. Measurement of X-ray intensity in mammography by a ferroelectric dosimeter

    NASA Astrophysics Data System (ADS)

    Alter, Albert J.

    2005-07-01

    Each year in the US over 20 million women undergo mammography, a relatively high dose x-ray examination of the breast, which is relatively sensitive to the carcinogenic effect of ionizing radiation. The radiation risk from mammography is usually expressed in terms of mean glandular dose (MGD) which is calculated as the product of measured entrance exposure (ESE) and a dose conversion factor which is a function of anode material, peak tube voltage (23 to 35 kVp), half-value layer, filtration, compressed breast thickness and breast composition. Mammographic units may have anodes made of molybdenum, rhodium or tungsten and filters of molybdenum, rhodium, or aluminum. In order to accommodate all these parameters, multiple extensive tables of conversion factors are required to cover the range of possibilities. Energy fluence and energy imparted are alternative measures of radiation hazard, which have been used in situations where geometry or filtration is unconventional such as computed tomography or fluoroscopy. Unfortunately, at the present there is no way to directly measure these quantities clinically. In radiation therapy applications, calorimetry has been used to measure energy absorbed. A ferroelectric-based detector has been described that measures energy fluence rate (x-ray intensity) for diagnostic x-ray, 50 to 140 kVp, aluminum filtered tungsten spectrum [Carvalho & Alter: IEEE Transactions 44(6) 1997]. This work explores use of ferroelectric detectors to measure energy fluence, energy fluence rate and energy imparted in mammography. A detector interfaced with a laptop computer was developed to allow measurements on clinical units of five different manufactures having targets of molybdenum, rhodium and tungsten and filters of molybdenum, rhodium, and aluminum of various thicknesses. The measurements provide the first values of energy fluence and energy imparted in mammography. These measurements are compared with conventional parameters such as entrance exposure and mean glandular dose as well as published values of energy imparted for other types of x-ray examinations. Advantage of measuring dose in terms of energy imparted in mammography are simplicity of comparison with other sources of radiation exposure and potential (relative ease) of measurement across a variety of anode and filter combinations.

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

    SciTech Connect

    Vig, Asger Laurberg; Enevoldsen, Nikolaj; Thilsted, Anil Haraksingh; Eriksen, Johan; Kristensen, Anders; Haldrup, Kristoffer; Feidenhans'l, Robert; Nielsen, Martin Meedom

    2009-11-15

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

  19. Probing electron recombination in atomic clusters excited by intense X-Ray fields

    NASA Astrophysics Data System (ADS)

    Georgescu, Ionut

    2011-05-01

    Shining an intense x-ray laser on large molecules and atomic clusters produces a large number of photo-electrons which leave the cluster in a highly charged state, leading to its Coulomb explosion. However, not all photo-electrons are able to leave. Some will be trapped in the cluster potential and will form a nano-plasma, slowing down the expansion and contributing to the optical response of the cluster. X-Rays couple to core electrons and the holes created via photo-ionization can relax via Auger decays, which heat up the plasma and accelerate the expansion on the one side, and repopulate the core levels for further ionization on the other side. Simulations for large Argon clusters (N = 923,2869) at current FEL parameters (1.5 keV, 5 fs, 100 ?J) have shown that collisional ionization and field fluctuations in the plasma can stop this chain reaction very early in the process by removing valence electrons. The expansion is slowed down and the core holes survive for very long times, their decay providing a probe of the electron recombination during the cluster expansion.

  20. Radiological characterization and water equivalency of genipin gel for x-ray and electron beam dosimetry

    NASA Astrophysics Data System (ADS)

    Gorjiara, Tina; Hill, Robin; Kuncic, Zdenka; Bosi, Stephen; Davies, Justin B.; Baldock, Clive

    2011-08-01

    The genipin radiochromic gel offers enormous potential as a three-dimensional dosimeter in advanced radiotherapy techniques. We have used several methods (including Monte Carlo simulation), to investigate the water equivalency of genipin gel by characterizing its radiological properties, including mass and electron densities, photon interaction cross sections, mass energy absorption coefficient, effective atomic number, collisional, radiative and total mass stopping powers and electron mass scattering power. Depth doses were also calculated for clinical kilovoltage and megavoltage x-ray beams as well as megavoltage electron beams. The mass density, electron density and effective atomic number of genipin were found to differ from water by less than 2%. For energies below 150 keV, photoelectric absorption cross sections are more than 3% higher than water due to the strong dependence on atomic number. Compton scattering and pair production interaction cross sections for genipin gel differ from water by less than 1%. The mass energy absorption coefficient is approximately 3% higher than water for energies <60 keV due to the dominance of photoelectric absorption in this energy range. The electron mass stopping power and mass scattering power differ from water by approximately 0.3%. X-ray depth dose curves for genipin gel agree to within 1% with those for water. Our results demonstrate that genipin gel can be considered water equivalent for kilovoltage and megavoltage x-ray beam dosimetry. For megavoltage electron beam dosimetry, however, our results suggest that a correction factor may be needed to convert measured dose in genipin gel to that of water, since differences in some radiological properties of up to 3% compared to water are observed. Our results indicate that genipin gel exhibits greater water equivalency than polymer gels and PRESAGE formulations.

  1. Study of X-ray polarization and e-beams generation during hot-spots formation in PF-discharges

    SciTech Connect

    Jakubowski, L.; Sadowski, M.; Baronova, E. O.; Vikhrev, V. V.

    1997-05-05

    Strong turbulence phenomena, as observed within dense magnetized plasmas, are of interest for theoretical and experimental studies. This paper concerns the filamentation and formation of 'hot-spots' in high current PF-type discharges, as well as the emission of fast electron beams and X-ray pulses. The generation of oriented e-beams can induce the polarization of X-rays, as observed within the MAJA-PF facility at SINS.

  2. Scattered hard X-ray and γ-ray generation from a chromatic electron beam

    NASA Astrophysics Data System (ADS)

    Coleman, J. E.; Welch, D. R.; Miller, C. L.

    2015-11-01

    An array of photon diagnostics has been deployed on a high power relativistic electron beam diode. Electrons are extracted through a 17.8 cm diode from the surface discharge of a carbon fiber velvet cathode with a nominal diode voltage of 3.8 MV. <10% of the 100 ns electron pulse is composed of off energy electrons (1-3 MeV) accelerated during the rise and fall of the pulse that impact the stainless steel beam pipe and generate a Bremsstrahlung spectrum of 0.1-3 MeV photons with a total count of 1011. The principal objective of these experiments is to quantify the electron beam dynamics and spatial dynamics of the hard X-ray and γ-ray flux generated in the diode region. A qualitative comparison of experimental and calculated results are presented, including time and energy resolved electron beam propagation and scattered photon measurements with X-ray PIN diodes and a photomultiplier tube indicating a dose dependence on the diode voltage >V4 and detected photon counts of nearly 106 at a radial distance of 1 m which corresponds to dose ˜40 μrad at 1 m.

  3. Beam hardening: analytical considerations of the effective attenuation coefficient of X-ray tomography.

    PubMed

    Alles, J; Mudde, R F

    2007-07-01

    Polychromatic x-ray beams traveling though material are prone to beam hardening, i.e., the high energy part of the incident spectrum gets over represented when traveling farther into the material. This study discusses the concept of a mean attenuation coefficient in a formal way. The total energy fluence is one-to-one related to the traveled distance in case of a polychromatic beam moving through a given, inhomogeneous material. On the basis of this one-to-one relation, it is useful to define a mean attenuation coefficient and study its decrease with depth. Our results are based on a novel parametrization of the energy dependence of the attenuation coefficient that allows for closed form evaluation of certain spectral integrals. This approach underpins the ad hoc semianalytical expressions given in the literature. An analytical model for the average attenuation coefficient is proposed that uses a simple fit of the attenuation coefficient as a function of the photon energy as input. It is shown that a simple extension of this model gives a rather good description of beam hardening for x-rays traveling through water. PMID:17821996

  4. Beam hardening: Analytical considerations of the effective attenuation coefficient of x-ray tomography

    SciTech Connect

    Alles, J.; Mudde, R. F.

    2007-07-15

    Polychromatic x-ray beams traveling though material are prone to beam hardening, i.e., the high energy part of the incident spectrum gets over represented when traveling farther into the material. This study discusses the concept of a mean attenuation coefficient in a formal way. The total energy fluence is one-to-one related to the traveled distance in case of a polychromatic beam moving through a given, inhomogeneous material. On the basis of this one-to-one relation, it is useful to define a mean attenuation coefficient and study its decrease with depth. Our results are based on a novel parametrization of the energy dependence of the attenuation coefficient that allows for closed form evaluation of certain spectral integrals. This approach underpins the ad hoc semianalytical expressions given in the literature. An analytical model for the average attenuation coefficient is proposed that uses a simple fit of the attenuation coefficient as a function of the photon energy as input. It is shown that a simple extension of this model gives a rather good description of beam hardening for x-rays traveling through water.

  5. Development of ion beam figuring system with electrostatic deflection for ultraprecise X-ray reflective optics

    NASA Astrophysics Data System (ADS)

    Yamada, Jumpei; Matsuyama, Satoshi; Sano, Yasuhisa; Yamauchi, Kazuto

    2015-09-01

    We developed an ion beam figuring system that utilizes electrostatic deflection. The system can produce an arbitrary shape by deterministically scanning the ion beam. The scan of the ion beam, which can be precisely controlled using only an electrical signal, enables us to avoid degradation of the mirror shape caused by imperfect acceleration or deceleration of a mechanically scanning stage. Additionally, this surface figuring method can easily be combined with X-ray metrology because the workpiece remains fixed during the figuring. We evaluated the figuring accuracy of the system by fabricating a plano-elliptical mirror for X-ray focusing. A mirror with a shape error of 1.4 nm root mean square (RMS) with a maximum removal depth of 992 nm, which corresponds to figuring accuracy of 0.14% RMS, was achieved. After the second shape corrections, an elliptical shape with a shape error of approximately 1 nm peak-to-valley, 0.48 nm RMS could be fabricated. Then, the mirror surface was smoothed by a low-energy ion beam. Consequently, a micro-roughness of 0.117 nm RMS, measured by atomic force microscopy, was achieved over an area of 1 1 ?m2.

  6. An adjustable short-focal length, high-gradient PMQ electron-beam final-focus system for the PLEIADES ultra-fast x-ray Thomson source

    NASA Astrophysics Data System (ADS)

    Lim, Jae-Ku

    In the span of a 100 year since the discovery of first x-rays by Roentgen that won him the first Nobel prize in physics, several types of radiation sources have been developed. Currently, radiations at extremely short wavelengths have only been accessed at synchrotron radiation sources. However, the current 3rd generation synchrotron sources can only produce x-rays of energy up to 60 keV and pulse lengths of several picoseconds long. But needs for shorter wavelength and shorter pulse duration radiations demanded by scientists to understand the nature of matter at atomic/molecular scale initiated the new scientific research for the production of sub-picosecond, hard x-rays. At the Lawrence Livermore National Laboratory, a Thomson x-ray source in the backscattering mode---a head-on collision between a high intensity Ti:Sapphire Chirped Pulse Amplification laser and a relativistic electron beam---called the PLEIADES (Picosecond Laser-Electron Inter-Action for the Dynamical Evaluation of Structures) laboratory has been developed. Early works demonstrated the production of quasi-monochromatic, femto-second long, hard x-rays. Initially reported x-ray flux was in the low range of 105--10 6 photons per shot. During the early stage of PLEIADES experiments, 15 T/m electromagnet final focusing quadrupoles (in a triplet lattice configuration) were employed to focus the beam to a 40-50 mum spot-size. A larger focal spot-size beam has a low-density of electron particles available at the interaction with incident photons, which leads to a low scattering probability. The current dissertation shows that by employing a 560 T/m PMQ (Permanent-Magnet Quadrupole) final focus system, an electron beam as small as 10-20 mum can be achieved. The implementation of this final focus system demonstrated the improvement of the total x-ray flux by two orders of magnitude. The PMQ final focus system also produced small electron beams consistently over 30-100 MeV electron beam energy, which enabled the production of x-ray energy over 40-140 keV. In this dissertation, the PLEIADES Thomson x-ray facility will be described in detail includes the 100 MeV linac and the FALCON laser system. Later, we will discuss the design, construction and implementation of the PMQ final focus system in the beamline. The measurement of electron beam parameters before and after the final focus system will be presented. The beam measurements at the interaction region were accomplished with the use of both OTR (Optical Transition Radiation) imaged by a CCD camera and the fast streak camera for respective spatial and temporal alignments. The theoretical analysis in "real beam" effects and spacetime beam jitter effects will be given to help understand the observations. A 3D simulation tool developed for x-ray data analysis was used to provide direct comparisons with the x-ray flux, spectrum distribution and transverse x-ray profile.

  7. Thermometric- and Acoustic-Based Beam Power Monitor for Ultra-Bright X-Rays

    SciTech Connect

    Bentsen, Gregory; /Rochester U. /SLAC

    2010-08-25

    A design for an average beam power monitor for ultra-bright X-ray sources is proposed that makes simultaneous use of calorimetry and radiation acoustics. Radiation incident on a solid target will induce heating and ultrasonic vibrations, both of which may be measured to give a fairly precise value of the beam power. The monitor is intended for measuring ultra-bright Free-Electron Laser (FEL) X-ray beams, for which traditional monitoring technologies such as photo-diodes or scintillators are unsuitable. The monitor consists of a Boron Carbide (B{sub 4}C) target designed to absorb most of the incident beam's energy. Resistance temperature detectors (RTD) and piezoelectric actuators are mounted on the outward faces of the target to measure the temperature changes and ultrasonic vibrations induced by the incident beam. The design was tested using an optical pulsed beam (780 nm, 120 and 360 Hz) from a Ti:sapphire oscillator at several energies between 0.8 and 2.6 mJ. The RTDs measured an increase in temperature of about 10 K over a period of several minutes. The piezoelectric sensors recorded ringing acoustic oscillations at 580 {+-} 40 kHz. Most importantly, the amplitude of the acoustic signals was observed to scale linearly with beam power up to 2 mJ of pulse energy. Above this pulse energy, the vibrational signals became nonlinear. Several causes for this nonlinearity are discussed, including amplifier saturation and piezoelectric saturation. Despite this nonlinearity, these measurements demonstrate the feasibility of such a beam power measurement device. The advantage of two distinct measurements (acoustic and thermometric) provides a useful method of calibration that is unavailable to current LCLS diagnostics tools.

  8. Fast X-Ray Fluorescence Camera Combined with Wide Band Pass Monochromatic Synchrotron Beam

    SciTech Connect

    Sakurai, Kenji; Mizusawa, Mari

    2004-05-12

    A double W/B4C multilayer monochromator (2d=50.4A) was commissioned for non-scanning X-ray fluorescence (XRF) imaging experiments. The combination of a brilliant multi-pole wiggler source and the present wide band pass monochromator permits 1.2 x 1013 photons/sec at the sample position for 8.04 keV X-rays. Energy resolution {delta}E and {delta}E/E are 300{approx}500 eV and {approx}5%, respectively. The exit beam height is constant for X-ray energy ranging from 5.5 to 13.0 keV. Indirect cooling of the 1st multilayer works successfully. In addition, a new fast CCD camera was developed for quick readout and transfer of the image data. It was found that the typical exposure time for one XRF image with 1000 x 1000 pixels is 0.03{approx}1 sec. This permits in-situ movie recording for the distribution of elements.

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

    SciTech Connect

    Cardarelli, Paolo; Di Domenico, Giovanni; Marziani, Michele; Mucollari, Irena; Pupillo, Gaia; Sisini, Francesco; Taibi, Angelo; Gambaccini, Mauro

    2012-10-01

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

  10. Determination of the energy dependence of the BC-408 plastic scintillation detector in medium energy x-ray beams

    NASA Astrophysics Data System (ADS)

    Ycel, H.; ubuku, ?.; Uyar, E.; Engin, Y.

    2014-11-01

    The energy dependence of the response of BC-408 plastic scintillator (PS), an approximately water-equivalent material, has been investigated by employing standardized x-ray beams. IEC RQA and ISO N series x-ray beam qualities, in the range of 40-100?kVp, were calibrated using a PTW-type ionization chamber. The energy response of a thick BC-408 PS detector was measured using the multichannel pulse height analysis method. The response of BC-408 PS increased gradually with increasing energy in the energy range of 40-80?kVp and then showed a flat behavior at about 80 to 120?kVp. This might be due to the self-attenuation of scintillation light by the scintillator itself and may also be partly due to the ionization quenching, leading to a reduction in the intensity of the light output from the scintillator. The results indicated that the sensitivity drop in BC-408 PS material at lower photon energies may be overcome by adding some high-Z elements to its polyvinyltoluene (PVT) base. The material modification may compensate for the drop in the response at lower photon energies. Thus plastic scintillation dosimetry is potentially suitable for applications in diagnostic radiology.

  11. Hard x-ray production from high intensity laser solid interactions

    SciTech Connect

    Sefcik, J. A., LLNL

    1998-06-03

    Intense laser (> 10{sup 21} W/cm{sup 2}) driven hard x-ray sources offer a new alternative to conventional electron accelerator bremsstrahlung sources. These laser driven sources offer considerable simplicity in design and cost advantage for multiple axis views and have the potential for much higher spatial and temporal resolution than is achievable with accelerator sources We have begun a series of experiments using the Petawatt Laser system at LLNL to determine the potential of these sources for radiography applications Absolutely calibrated spectra extending to 20 MeV and high resolution radiographs through a {rho}r{>=}150 gm/cm{sup 2} have been obtained The physics of these sources and the scaling relationships and laser technology required to provide the dose levels necessary for radiography applications will be discussed Diagnostics of the laser produced electrons and photons will be addressed

  12. Improving x-ray fluorescence signal for benchtop polychromatic cone-beam x-ray fluorescence computed tomography by incident x-ray spectrum optimization: A Monte Carlo study

    SciTech Connect

    Manohar, Nivedh; Cho, Sang Hyun

    2014-10-15

    Purpose: To develop an accurate and comprehensive Monte Carlo (MC) model of an experimental benchtop polychromatic cone-beam x-ray fluorescence computed tomography (XFCT) setup and apply this MC model to optimize incident x-ray spectrum for improving production/detection of x-ray fluorescence photons from gold nanoparticles (GNPs). Methods: A detailed MC model, based on an experimental XFCT system, was created using the Monte Carlo N-Particle (MCNP) transport code. The model was validated by comparing MC results including x-ray fluorescence (XRF) and scatter photon spectra with measured data obtained under identical conditions using 105 kVp cone-beam x-rays filtered by either 1 mm of lead (Pb) or 0.9 mm of tin (Sn). After validation, the model was used to investigate the effects of additional filtration of the incident beam with Pb and Sn. Supplementary incident x-ray spectra, representing heavier filtration (Pb: 2 and 3 mm; Sn: 1, 2, and 3 mm) were computationally generated and used with the model to obtain XRF/scatter spectra. Quasimonochromatic incident x-ray spectra (81, 85, 90, 95, and 100 keV with 10 keV full width at half maximum) were also investigated to determine the ideal energy for distinguishing gold XRF signal from the scatter background. Fluorescence signal-to-dose ratio (FSDR) and fluorescence-normalized scan time (FNST) were used as metrics to assess results. Results: Calculated XRF/scatter spectra for 1-mm Pb and 0.9-mm Sn filters matched (r ≥ 0.996) experimental measurements. Calculated spectra representing additional filtration for both filter materials showed that the spectral hardening improved the FSDR at the expense of requiring a much longer FNST. In general, using Sn instead of Pb, at a given filter thickness, allowed an increase of up to 20% in FSDR, more prominent gold XRF peaks, and up to an order of magnitude decrease in FNST. Simulations using quasimonochromatic spectra suggested that increasing source x-ray energy, in the investigated range of 81–100 keV, increased the FSDR up to a factor of 20, compared to 1 mm Pb, and further facilitated separation of gold XRF peaks from the scatter background. Conclusions: A detailed MC model of an experimental benchtop XFCT system has been developed and validated. In exemplary calculations to illustrate the usefulness of this model, it was shown that potential use of quasimonochromatic spectra or judicious choice of filter material/thickness to tailor the spectrum of a polychromatic x-ray source can significantly improve the performance of benchtop XFCT, while considering trade-offs between FSDR and FNST. As demonstrated, the current MC model is a reliable and powerful computational tool that can greatly expedite the further development of a benchtop XFCT system for routine preclinical molecular imaging with GNPs and other metal probes.

  13. Improving x-ray fluorescence signal for benchtop polychromatic cone-beam x-ray fluorescence computed tomography by incident x-ray spectrum optimization: A Monte Carlo study

    PubMed Central

    Manohar, Nivedh; Jones, Bernard L.; Cho, Sang Hyun

    2014-01-01

    Purpose: To develop an accurate and comprehensive Monte Carlo (MC) model of an experimental benchtop polychromatic cone-beam x-ray fluorescence computed tomography (XFCT) setup and apply this MC model to optimize incident x-ray spectrum for improving production/detection of x-ray fluorescence photons from gold nanoparticles (GNPs). Methods: A detailed MC model, based on an experimental XFCT system, was created using the Monte Carlo N-Particle (MCNP) transport code. The model was validated by comparing MC results including x-ray fluorescence (XRF) and scatter photon spectra with measured data obtained under identical conditions using 105 kVp cone-beam x-rays filtered by either 1 mm of lead (Pb) or 0.9 mm of tin (Sn). After validation, the model was used to investigate the effects of additional filtration of the incident beam with Pb and Sn. Supplementary incident x-ray spectra, representing heavier filtration (Pb: 2 and 3 mm; Sn: 1, 2, and 3 mm) were computationally generated and used with the model to obtain XRF/scatter spectra. Quasimonochromatic incident x-ray spectra (81, 85, 90, 95, and 100 keV with 10 keV full width at half maximum) were also investigated to determine the ideal energy for distinguishing gold XRF signal from the scatter background. Fluorescence signal-to-dose ratio (FSDR) and fluorescence-normalized scan time (FNST) were used as metrics to assess results. Results: Calculated XRF/scatter spectra for 1-mm Pb and 0.9-mm Sn filters matched (r ? 0.996) experimental measurements. Calculated spectra representing additional filtration for both filter materials showed that the spectral hardening improved the FSDR at the expense of requiring a much longer FNST. In general, using Sn instead of Pb, at a given filter thickness, allowed an increase of up to 20% in FSDR, more prominent gold XRF peaks, and up to an order of magnitude decrease in FNST. Simulations using quasimonochromatic spectra suggested that increasing source x-ray energy, in the investigated range of 81100 keV, increased the FSDR up to a factor of 20, compared to 1 mm Pb, and further facilitated separation of gold XRF peaks from the scatter background. Conclusions: A detailed MC model of an experimental benchtop XFCT system has been developed and validated. In exemplary calculations to illustrate the usefulness of this model, it was shown that potential use of quasimonochromatic spectra or judicious choice of filter material/thickness to tailor the spectrum of a polychromatic x-ray source can significantly improve the performance of benchtop XFCT, while considering trade-offs between FSDR and FNST. As demonstrated, the current MC model is a reliable and powerful computational tool that can greatly expedite the further development of a benchtop XFCT system for routine preclinical molecular imaging with GNPs and other metal probes. PMID:25281958

  14. Semi-empirical model for fluorescence lines evaluation in diagnostic x-ray beams.

    PubMed

    Bontempi, Marco; Andreani, Lucia; Labanti, Claudio; Costa, Paulo Roberto; Rossi, Pier Luca; Baldazzi, Giuseppe

    2016-01-01

    Diagnostic x-ray beams are composed of bremsstrahlung and discrete fluorescence lines. The aim of this study is the development of an efficient model for the evaluation of the fluorescence lines. The most important electron ionization models are analyzed and implemented. The model results were compared with experimental data and with other independent spectra presented in the literature. The implemented peak models allow the discrimination between direct and indirect radiation emitted from tungsten anodes. The comparison with the independent literature spectra indicated a good agreement. PMID:26497807

  15. A portable molecular beam epitaxy system for in situ x-ray investigations at synchrotron beamlines

    SciTech Connect

    Slobodskyy, T.; Schroth, P.; Grigoriev, D.; Minkevich, A. A.; Baumbach, T.; Hu, D. Z.; Schaadt, D. M.

    2012-10-15

    A portable synchrotron molecular beam epitaxy (MBE) system is designed and applied for in situ investigations. The growth chamber is equipped with all the standard MBE components such as effusion cells with shutters, main shutter, cooling shroud, manipulator, reflection high energy electron diffraction setup, and pressure gauges. The characteristic feature of the system is the beryllium windows which are used for in situ x-ray measurements. An UHV sample transfer case allows in vacuo transfer of samples prepared elsewhere. We describe the system design and demonstrate its performance by investigating the annealing process of buried InGaAs self-organized quantum dots.

  16. A portable molecular beam epitaxy system for in situ x-ray investigations at synchrotron beamlines

    NASA Astrophysics Data System (ADS)

    Slobodskyy, T.; Schroth, P.; Grigoriev, D.; Minkevich, A. A.; Hu, D. Z.; Schaadt, D. M.; Baumbach, T.

    2012-10-01

    A portable synchrotron molecular beam epitaxy (MBE) system is designed and applied for in situ investigations. The growth chamber is equipped with all the standard MBE components such as effusion cells with shutters, main shutter, cooling shroud, manipulator, reflection high energy electron diffraction setup, and pressure gauges. The characteristic feature of the system is the beryllium windows which are used for in situ x-ray measurements. An UHV sample transfer case allows in vacuo transfer of samples prepared elsewhere. We describe the system design and demonstrate its performance by investigating the annealing process of buried InGaAs self-organized quantum dots.

  17. A portable molecular beam epitaxy system for in situ x-ray investigations at synchrotron beamlines.

    PubMed

    Slobodskyy, T; Schroth, P; Grigoriev, D; Minkevich, A A; Hu, D Z; Schaadt, D M; Baumbach, T

    2012-10-01

    A portable synchrotron molecular beam epitaxy (MBE) system is designed and applied for in situ investigations. The growth chamber is equipped with all the standard MBE components such as effusion cells with shutters, main shutter, cooling shroud, manipulator, reflection high energy electron diffraction setup, and pressure gauges. The characteristic feature of the system is the beryllium windows which are used for in situ x-ray measurements. An UHV sample transfer case allows in vacuo transfer of samples prepared elsewhere. We describe the system design and demonstrate its performance by investigating the annealing process of buried InGaAs self-organized quantum dots. PMID:23126809

  18. Projection phase contrast microscopy with a hard x-ray nanofocused beam: Defocus and contrast transfer

    SciTech Connect

    Salditt, T.; Giewekemeyer, K.; Fuhse, C.; Krueger, S. P.; Tucoulou, R.; Cloetens, P.

    2009-05-01

    We report a projection phase contrast microscopy experiment using hard x-ray pink beam undulator radiation focused by an adaptive mirror system to 100-200 nm spot size. This source is used to illuminate a lithographic test pattern with a well-controlled range of spatial frequencies. The oscillatory nature of the contrast transfer function with source-to-sample distance in this holographic imaging scheme is quantified and the validity of the weak phase object approximation is confirmed for the experimental conditions.

  19. Intensity-dependent quasi-periodic oscillations in the X-ray flux of GX5 - 1

    NASA Technical Reports Server (NTRS)

    Van Der Klis, M.; Jansen, F.; Van Paradijs, J.; Van Den Heuvel, E. P. J.; Lewin, W. H. G.

    1985-01-01

    The X-ray flux of the bright galactic bulge source GX5 - 1 shows intensity-dependent quasi-periodic oscillations between 20 and 40 Hz, appearing as a broad peak in the power spectrum whose centroid frequency, width, and integrated excess power strongly depend on the source intensity. The strength and steepness of low-frequency noise present in the power spectra below 15 Hz also depend on the source intensity. No evidence is found for coherent X-ray pulsations between 0.5 and 2000 Hz. Possible mechanisms to explain these new phenomena are discussed.

  20. X-ray Interferometry with Transmissive Beam Combiners for Ultra-High Angular Resolution Astronomy

    NASA Technical Reports Server (NTRS)

    Skinner, G. K.; Krismanic, John F.

    2009-01-01

    Abstract Interferometry provides one of the possible routes to ultra-high angular resolution for X-ray and gamma-ray astronomy. Sub-micro-arc-second angular resolution, necessary to achieve objectives such as imaging the regions around the event horizon of a super-massive black hole at the center of an active galaxy, can be achieved if beams from parts of the incoming wavefront separated by 100s of meters can be stably and accurately brought together at small angles. One way of achieving this is by using grazing incidence mirrors. We here investigate an alternative approach in which the beams are recombined by optical elements working in transmission. It is shown that the use of diffractive elements is a particularly attractive option. We report experimental results from a simple 2-beam interferometer using a low-cost commercially available profiled film as the diffractive elements. A rotationally symmetric filled (or mostly filled) aperture variant of such an interferometer, equivalent to an X-ray axicon, is shown to offer a much wider bandpass than either a Phase Fresnel Lens (PFL) or a PFL with a refractive lens in an achromatic pair. Simulations of an example system are presented.

  1. X-ray cone-beam computed tomography: principles, applications, challenges and solutions

    NASA Astrophysics Data System (ADS)

    Noo, Frederic

    2010-03-01

    In the nineties, x-ray computed tomography, commonly referred to as CT, seemed to be on the track to become old technology, bound to be replaced by more sophisticated techniques such as magnetic resonance imaging, due in particular to the harmful effects of x-ray radiation exposure. Yet, the new century brought with it new technology that allowed a complete change in trends and re-affirmed CT as an essential tool in radiology. For instance, the popularity of CT in 2007 was such that approximately 68.7 million CT examinations were performed in the United States, which was nearly 2.5 times the number of magnetic resonance (MRI) examinations. More than that, CT has expanded beyond its conventional diagnostic role; CT is now used routinely in interventional radiology and also in radiation therapy treatment. The technology advances that allowed the revival of CT are those that made fast, accurate cone-beam data acquisition possible. Nowadays, cone-beam data acquisition allows scanning large volumes with isotropic sub-millimeter spatial resolution in a very fast time, which can be as short as 500ms for cardiac imaging. The principles of cone-beam imaging will be first reviewed. Then a discussion of its applications will be given. Old and new challenges will be presented along the way with current solutions.

  2. Pulse-periodic generation of supershort avalanche electron beams and X-ray emission

    NASA Astrophysics Data System (ADS)

    Baksht, E. Kh.; Burachenko, A. G.; Erofeev, M. V.; Tarasenko, V. F.

    2014-05-01

    Pulse-periodic generation of supershort avalanche electron beams (SAEBs) and X-ray emission in nitrogen, as well as the transition from a single-pulse mode to a pulse-periodic mode with a high repetition frequency, was studied experimentally. It is shown that, in the pulse-periodic mode, the full width at halfmaximum of the SAEB is larger and the decrease rate of the gap voltage is lower than those in the single-pulse mode. It is found that, when the front duration of the voltage pulse at a nitrogen pressure of 90 Torr decreases from 2.5 to 0.3 ns, the X-ray exposure dose in the pulse-periodic mode increases by more than one order of magnitude and the number of SAEB electrons also increases. It is shown that, in the pulse-periodic mode of a diffuse discharge, gas heating in the discharge gap results in a severalfold increase in the SAEB amplitude (the number of electrons in the beam). At a generator voltage of 25 kV, nitrogen pressure of 90 Torr, and pulse repetition frequency of 3.5 kHz, a runaway electron beam was detected behind the anode foil.

  3. Supershort avalanche electron beams and x-ray in high-pressure nanosecond discharges

    NASA Astrophysics Data System (ADS)

    Tarasenko, V. F.; Baksht, E. H.; Kostyrya, I. D.; Lomaev, M. I.; Rybka, D. V.

    2008-10-01

    The properties of a supershort avalanche electron beam (S AEB) and X-ray radiation produced using a nanosecond volume discharge are examined. An electron beam of the runaway electrons with amplitude of ~ 50 A has been obtained in air atmospheric pressure. It is reported that S AEB is formed in the angle above 2π sr. Three groups of the runaway electrons are formed in a gas diode under atmospheric air pressure, when nanosecond voltage pulses with amplitude of hundreds of kilovolts are applied. The electron beam has been generated behind a 45 μm thick AlBe foil in SF6 and Xe under the pressure of 2 arm, and in He under the pressure of about 12 atm. The paper gives the analysis of a generation mechanism of SAEB.

  4. White Beam Slits and Pink Beam Slits for the Hard X-ray Nanoprobe Beamline at the Advanced Photon Source

    SciTech Connect

    Benson, C.; Jaski, Y.; Powers, T.; Schmidt, O.; Rossi, E.; Maser, J.

    2007-01-19

    A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a clean cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam.The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits' accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.

  5. White beam slits and pink beam slits for the hard x-ray nanoprobe beamline at the Advanced Photon Source.

    SciTech Connect

    Benson, C.; Jaski, Y.; Maser, J.; Powers, T.; Schmidt, O.; Rossi, E.

    2007-01-01

    A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a clean cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam. The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.

  6. An empirical model of diagnostic x-ray attenuation under narrow-beam geometry

    PubMed Central

    Mathieu, Kelsey B.; Kappadath, S. Cheenu; White, R. Allen; Atkinson, E. Neely; Cody, Dianna D.

    2011-01-01

    Purpose: The purpose of this study was to develop and validate a mathematical model to describe narrow-beam attenuation of kilovoltage x-ray beams for the intended applications of half-value layer (HVL) and quarter-value layer (QVL) estimations, patient organ shielding, and computer modeling. Methods: An empirical model, which uses the Lambert W function and represents a generalized Lambert-Beer law, was developed. To validate this model, transmission of diagnostic energy x-ray beams was measured over a wide range of attenuator thicknesses [0.49–33.03 mm Al on a computed tomography (CT) scanner, 0.09–1.93 mm Al on two mammography systems, and 0.1–0.45 mm Cu and 0.49–14.87 mm Al using general radiography]. Exposure measurements were acquired under narrow-beam geometry using standard methods, including the appropriate ionization chamber, for each radiographic system. Nonlinear regression was used to find the best-fit curve of the proposed Lambert W model to each measured transmission versus attenuator thickness data set. In addition to validating the Lambert W model, we also assessed the performance of two-point Lambert W interpolation compared to traditional methods for estimating the HVL and QVL [i.e., semilogarithmic (exponential) and linear interpolation]. Results: The Lambert W model was validated for modeling attenuation versus attenuator thickness with respect to the data collected in this study (R2 > 0.99). Furthermore, Lambert W interpolation was more accurate and less sensitive to the choice of interpolation points used to estimate the HVL and∕or QVL than the traditional methods of semilogarithmic and linear interpolation. Conclusions: The proposed Lambert W model accurately describes attenuation of both monoenergetic radiation and (kilovoltage) polyenergetic beams (under narrow-beam geometry). PMID:21928626

  7. An empirical model of diagnostic x-ray attenuation under narrow-beam geometry

    SciTech Connect

    Mathieu, Kelsey B.; Kappadath, S. Cheenu; White, R. Allen; Atkinson, E. Neely; Cody, Dianna D.

    2011-08-15

    Purpose: The purpose of this study was to develop and validate a mathematical model to describe narrow-beam attenuation of kilovoltage x-ray beams for the intended applications of half-value layer (HVL) and quarter-value layer (QVL) estimations, patient organ shielding, and computer modeling. Methods: An empirical model, which uses the Lambert W function and represents a generalized Lambert-Beer law, was developed. To validate this model, transmission of diagnostic energy x-ray beams was measured over a wide range of attenuator thicknesses [0.49-33.03 mm Al on a computed tomography (CT) scanner, 0.09-1.93 mm Al on two mammography systems, and 0.1-0.45 mm Cu and 0.49-14.87 mm Al using general radiography]. Exposure measurements were acquired under narrow-beam geometry using standard methods, including the appropriate ionization chamber, for each radiographic system. Nonlinear regression was used to find the best-fit curve of the proposed Lambert W model to each measured transmission versus attenuator thickness data set. In addition to validating the Lambert W model, we also assessed the performance of two-point Lambert W interpolation compared to traditional methods for estimating the HVL and QVL [i.e., semilogarithmic (exponential) and linear interpolation]. Results: The Lambert W model was validated for modeling attenuation versus attenuator thickness with respect to the data collected in this study (R{sup 2} > 0.99). Furthermore, Lambert W interpolation was more accurate and less sensitive to the choice of interpolation points used to estimate the HVL and/or QVL than the traditional methods of semilogarithmic and linear interpolation. Conclusions: The proposed Lambert W model accurately describes attenuation of both monoenergetic radiation and (kilovoltage) polyenergetic beams (under narrow-beam geometry).

  8. Subacute Neuropathological Effects of Microplanar Beams of X-Rays from a Synchrotron Wiggler

    NASA Astrophysics Data System (ADS)

    Slatkin, D. N.; Spanne, P.; Dilmanian, F. A.; Gebbers, J.-O.; Laissue, J. A.

    1995-09-01

    Microplanar beam radiation therapy has been proposed to treat brain tumors by using a series of rapid exposures to an array of parallel x-ray beams, each beam having uniform microscopic thickness and macroscopic breadth (i.e., microplanar). Thirty-six rats were exposed head-on either to an upright 4-mm-high, 20- or 37-μ m-wide beam or to a horizontal 7-mm-wide, 42-μ m-high beam of mostly 32- to 126-keV, minimally divergent x-rays from the X17 wiggler at the National Synchrotron Light Source at Brookhaven National Laboratory. Parallel slices of the head, separated at either 75 or 200 μ m on center, were exposed sequentially at 310-650 grays (Gy) per second until each skin-entrance absorbed dose reached 312, 625, 1250, 2500, 5000, or 10,000 Gy. The rats were euthanized 2 weeks or 1 month later. Two rats with 10,000-Gy-entrance slices developed brain tissue necrosis. All the other 10,000- and 5000-Gy-entrance slices and some of the 2500- and 1250-Gy-entrance slices showed loss of neuronal and astrocytic nuclei and their perikarya. No other kind of brain damage was evident histologically in any rat with entrance absorbed doses <=5000 Gy. Brain tissues in and between all the 312- and 625-Gy-entrance slices appeared normal. This unusual resistance to necrosis is central to the rationale of microplanar beam radiation therapy for brain tumors.

  9. Flash X-Ray (FXR) Accelerator Optimization Beam-induced Voltage Simulation and TDR Measurements

    SciTech Connect

    Ong, M M; Vogtlin, G E

    2005-05-12

    Lawrence Livermore National Laboratory (LLNL) is evaluating design alternatives to improve the voltage regulation in our Flash X-Ray (FXR) accelerator cell and pulse-power system. The goal is to create a more mono-energetic electron beam. When an electron beam crosses the energized gap of an accelerator cell, the electron energy is increased. However, the beam with the associated electromagnetic wave also looses a small amount of energy because of the increased impedance seen across the gap. The beam-induced voltage at the gap is time varying. This creates beam energy variations that we need to understand and control. A high-fidelity computer simulation of the beam and cell interaction has been completed to quantify the time varying induced voltage at the gap. The cell and pulse-power system was characterized using a Time-domain Reflectometry (TDR) measurement technique with a coaxial air-line to drive the cell gap. The beam-induced cell voltage is computed by convoluting the cell impedance with measured beam current. The voltage was checked against other measurements to validate the accuracy.

  10. Determination of electron energy, spectral width, and beam divergence at the exit window for clinical megavoltage x-ray beams

    PubMed Central

    Sawkey, D. L.; Faddegon, B. A.

    2009-01-01

    Monte Carlo simulations of x-ray beams typically take parameters of the electron beam in the accelerating waveguide to be free parameters. In this paper, a methodology is proposed and implemented to determine the energy, spectral width, and beam divergence of the electron source. All treatment head components were removed from the beam path, leaving only the exit window. With the x-ray target and flattener out of the beam, uncertainties in physical characteristics and relative position of the target and flattening filter, and in spot size, did not contribute to uncertainty in the energy. Beam current was lowered to reduce recombination effects. The measured dose distributions were compared with Monte Carlo simulation of the electron beam through the treatment head to extract the electron source characteristics. For the nominal 6 and 18 MV x-ray beams, the energies were 6.510.15 and 13.90.2 MeV, respectively, with the uncertainties resulting from uncertainties in the detector position in the measurement and in the stopping power in the simulations. Gaussian spectral distributions were used, with full widths at half maximum ranging from 204% at 6 MV to 134% at 18 MV required to match the fall-off portion of the percent-depth ionization curve. Profiles at the depth of maximum dose from simulations that used the manufacturer-specified exit window geometry and no beam divergence were 23 cm narrower than measured profiles. Two simulation configurations yielding the measured profile width were the manufacturer-specified exit window thickness with electron source divergences of 3.3 at 6 MV and 1.8 at 18 MV and an exit window 40% thicker than the manufacturers specification with no beam divergence. With the x-ray target in place (and no flattener), comparison of measured to simulated profiles sets upper limits on the electron source divergences of 0.2 at 6 MV and 0.1 at 18 MV. A method of determining source characteristics without mechanical modification of the treatment head, and therefore feasible in clinics, is presented. The energies and spectral widths determined using this method agree with those determined with only the exit window in the beam path. PMID:19378730

  11. X-ray beam lines and beam line components for the SLAC Linac Coherent Light Source (LCLS)

    SciTech Connect

    Tatchyn, R.; Pianetta, P.

    1993-04-01

    The LCLS is a novel high-brightness x-ray source designed to operate in the 300--400 eV range. In contrast to conventional synchrotron radiation sources, its output pulses will be characterized by unprecedented levels of brevity and peak power. In this paper we present recently-developed beam line layouts and design features intended to optimize the delivery of the LCLS photons to various experimental stations.

  12. Integral window/photon beam position monitor and beam flux detectors for x-ray beams

    DOEpatents

    Shu, Deming (Darien, IL); Kuzay, Tuncer M. (Naperville, IL)

    1995-01-01

    A monitor/detector assembly in a synchrotron for either monitoring the position of a photon beam or detecting beam flux may additionally function as a vacuum barrier between the front end and downstream segment of the beamline in the synchrotron. A base flange of the monitor/detector assembly is formed of oxygen free copper with a central opening covered by a window foil that is fused thereon. The window foil is made of man-made materials, such as chemical vapor deposition diamond or cubic boron nitrate and in certain configurations includes a central opening through which the beams are transmitted. Sensors of low atomic number materials, such as aluminum or beryllium, are laid on the window foil. The configuration of the sensors on the window foil may be varied depending on the function to be performed. A contact plate of insulating material, such as aluminum oxide, is secured to the base flange and is thereby clamped against the sensor on the window foil. The sensor is coupled to external electronic signal processing devices via a gold or silver lead printed onto the contact plate and a copper post screw or alternatively via a copper screw and a copper spring that can be inserted through the contact plate and coupled to the sensors. In an alternate embodiment of the monitor/detector assembly, the sensors are sandwiched between the window foil of chemical vapor deposition diamond or cubic boron nitrate and a front foil made of similar material.

  13. Using an electron beam to produce a bright isotropic subsurface x-ray source for back illumination in landmine detection

    NASA Astrophysics Data System (ADS)

    Retsky, Michael W.

    2005-06-01

    Why is it so difficult to detect concealed shallow buried landmines while it is relatively easy to image and detect cancers within the human body? One reason is that in medical x-ray imaging, the source is on one side of the body and the detectors are on the other. This is back-illumination, the optimal orientation for x-ray imaging. Can back-illumination be used in landmine detection? That is, is it possible to generate sufficient xrays 10 or more cm below the soil surface so that suitable detectors above ground could be used to image shallow buried objects including landmines? In an x-ray tube, high voltage electron beams produce x-rays by electron deceleration (bremsstrahlung) and induced orbital transitions. It may be possible to produce 1000 amp short pulses of electrons at 30 MeV using an electron gun with multiple field emitters. (This is a section of an antiballistic missile device proposed at SPIE Defense and Security 2004.) Electron beams of such energy have range of approximately 100 m in air and 10-15 cm in soil. This 5-10 m tall device could be carried by balloon, helicopter or land vehicle. X-ray production efficiency at 30 MeV is over 50 fold higher compared to medical x-ray tube efficiency. Such a device would produce a bright isotropic source of x-rays in a subsurface plume that might be usable in landmine detection.

  14. Two-dimensional transverse coherence measurement of hard-x-ray beams using near-field speckle

    NASA Astrophysics Data System (ADS)

    Kashyap, Yogesh; Wang, Hongchang; Sawhney, Kawal

    2015-09-01

    Knowledge of the transverse coherence of hard x rays is essential, not only for understanding the source properties, but also to study the impact of x-ray optics. However, the precise measurement of transverse coherence in the x-ray regime is more difficult than in the visible light regime since it often involves complex experimental setups or sophisticated x-ray optics. In this paper, we present a model-free method to measure transverse coherence properties of x-ray beams by using a simple phase membrane. Our method allows one to map the two-dimensional source distribution in the transverse plane by analyzing the power spectrum of x-ray near-field speckle patterns, which are collected at a single distance only. The method has been validated by performing measurements for a range of source sizes, which was achieved by varying the vertical coupling of the electron beam in the Diamond storage ring. We expect that this method will be widely used in transverse coherence measurements for both synchrotron sources and x-ray free-electron lasers.

  15. Fast GPU-based absolute intensity determination for energy-dispersive X-ray Laue diffraction

    NASA Astrophysics Data System (ADS)

    Alghabi, F.; Send, S.; Schipper, U.; Abboud, A.; Pietsch, U.; Kolb, A.

    2016-01-01

    This paper presents a novel method for fast determination of absolute intensities in the sites of Laue spots generated by a tetragonal hen egg-white lysozyme crystal after exposure to white synchrotron radiation during an energy-dispersive X-ray Laue diffraction experiment. The Laue spots are taken by means of an energy-dispersive X-ray 2D pnCCD detector. Current pnCCD detectors have a spatial resolution of 384 × 384 pixels of size 75 × 75 μm2 each and operate at a maximum of 400 Hz. Future devices are going to have higher spatial resolution and frame rates. The proposed method runs on a computer equipped with multiple Graphics Processing Units (GPUs) which provide fast and parallel processing capabilities. Accordingly, our GPU-based algorithm exploits these capabilities to further analyse the Laue spots of the sample. The main contribution of the paper is therefore an alternative algorithm for determining absolute intensities of Laue spots which are themselves computed from a sequence of pnCCD frames. Moreover, a new method for integrating spectral peak intensities and improved background correction, a different way of calculating mean count rate of the background signal and also a new method for n-dimensional Poisson fitting are presented.We present a comparison of the quality of results from the GPU-based algorithm with the quality of results from a prior (base) algorithm running on CPU. This comparison shows that our algorithm is able to produce results with at least the same quality as the base algorithm. Furthermore, the GPU-based algorithm is able to speed up one of the most time-consuming parts of the base algorithm, which is n-dimensional Poisson fitting, by a factor of more than 3. Also, the entire procedure of extracting Laue spots' positions, energies and absolute intensities from a raw dataset of pnCCD frames is accelerated by a factor of more than 3.

  16. Monte Carlo simulation of an x-ray volume imaging cone beam CT unit

    SciTech Connect

    Spezi, Emiliano; Downes, Patrick; Radu, Emil; Jarvis, Richard

    2009-01-15

    In this work the authors characterized the radiation field produced by a kilovolt cone beam computed tomography (CBCT) unit integrated in the Elekta Synergy linear accelerator. The x-ray volume imaging (XVI) radiation unit was modeled in detail using the BEAMNRC Monte Carlo (MC) code system. The simulations of eight collimator cassettes and the neutral filter F0 were successfully carried out. MC calculations from the EGSNRC code DOSXYZNRC were benchmarked against measurements in water. A large set of depth dose and lateral profiles was acquired with the ionization chamber in water, with the x-ray tube in a stationary position, and with the beam energy set to 120 kV. Measurements for all the available collimator cassettes were compared with calculations, showing very good agreement (<2% in most cases). Furthermore, half value layer measurements were carried out and used to validate the MC model of the XVI unit. In this case dose calculations were performed with the EGSNRC code cavity and these showed excellent agreement. In this manuscript the authors also report on the optimization work of the relevant parameters that influenced the development of the MC model. The dosimetric part of this work was very useful in characterizing the XVI radiation output for the energy of interest. The detailed simulation part of the work is the first step toward an accurate MC based assessment of the dose delivered to patients during routine CBCT scans for image and dose guided radiotherapy.

  17. Monte Carlo simulation of an x-ray volume imaging cone beam CT unit.

    PubMed

    Spezi, Emiliano; Downes, Patrick; Radu, Emil; Jarvis, Richard

    2009-01-01

    In this work the authors characterized the radiation field produced by a kilovolt cone beam computed tomography (CBCT) unit integrated in the Elekta Synergy linear accelerator. The x-ray volume imaging (XVI) radiation unit was modeled in detail using the BEAMNRC Monte Carlo (MC) code system. The simulations of eight collimator cassettes and the neutral filter F0 were successfully carried out. MC calculations from the EGSNRC code DOSXYZNRC were benchmarked against measurements in water. A large set of depth dose and lateral profiles was acquired with the ionization chamber in water, with the x-ray tube in a stationary position, and with the beam energy set to 120 kV. Measurements for all the available collimator cassettes were compared with calculations, showing very good agreement (< 2% in most cases). Furthermore, half value layer measurements were carried out and used to validate the MC model of the XVI unit. In this case dose calculations were performed with the EGSNRC code cavity and these showed excellent agreement. In this manuscript the authors also report on the optimization work of the relevant parameters that influenced the development of the MC model. The dosimetric part of this work was very useful in characterizing the XVI radiation output for the energy of interest. The detailed simulation part of the work is the first step toward an accurate MC based assessment of the dose delivered to patients during routine CBCT scans for image and dose guided radiotherapy. PMID:19235381

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  19. Beam Damage of Poly(Vinyl Chloride) [PVC] Film as Observed by X-ray Photoelectron Spectroscopy

    SciTech Connect

    Engelhard, Mark H.; Krishna, Abhilash; Kulkarni, Pranita B.; Lee, Chi-Ying M.; Baer, Donald R.

    2003-03-08

    XPS spectra of a spin-coated film poly(vinyl chloride) (PVC) were collected over a period of 243 minutes at 303 K to determine specimen damage during long exposures to monochromatic Al Ka x-rays. For this PVC film we measured the loss of chlorine as a function of time by rastering a focused 104.6 w 100 um diameter x-ray beam over a 1.4 mm x 0.2 mm area on the sample.

  20. Dosimetric application of a special pencil ionization chamber in radiotherapy X-ray beams

    NASA Astrophysics Data System (ADS)

    Neves, Lucio P.; Perini, Ana P.; Fernndez-Varea, Jos M.; Cassola, Vagner F.; Kramer, Richard; Khoury, Helen J.; Caldas, Linda V. E.

    2014-02-01

    The aim of this work was to study the performance of a pencil ionization chamber with a sensitive volume of only 1.06 cm3 and a length of 3.0 cm, developed at the Calibration Laboratory of the IPEN, in very low-energy radiotherapy X-ray beams. These beams are still used for certain skin cancer treatments due to their rapid attenuation in tissue. The dosimeter performance was evaluated in some tests proposed by the IEC 60731 standard: short- and long-term stability and linearity of response. For a complete analysis of the dosimeter response, the EGSnrc Monte Carlo simulation was utilized to investigate the influence of its different parts on the ionization chamber response. All results of the tests were in accordance with the recommended limits, and this work shows that it is possible to extend the application of this pencil-type ionization chamber developed at the LCI.

  1. Ptychographical imaging of the phase vortices in the x-ray beam formed by nanofocusing lenses

    NASA Astrophysics Data System (ADS)

    Dzhigaev, D.; Lorenz, U.; Kurta, R. P.; Seiboth, F.; Stankevic, T.; Mickevicius, S.; Singer, A.; Shabalin, A.; Yefanov, O. M.; Strikhanov, M. N.; Falkenberg, G.; Schroer, C. G.; Feidenhans'l, R.; Vartanyants, I. A.

    2014-04-01

    We present the ptychographical reconstruction of the x-ray beam formed by nanofocusing lenses (NFLs) containing a number of phase singularities (vortices) in the vicinity of the focal plane. As a test object Siemens star pattern was used with the finest features of 50 nm for ptychographical measurements. The extended ptychographical iterative engine (ePIE) algorithm was applied to retrieve both complex illumination and object functions from the set of diffraction patterns. The reconstruction revealed the focus size of 91.4±1.1 nm in horizontal and 70±0.3 nm in vertical direction at full width at half maximum (FWHM). The complex probe function was propagated along the optical axis of the beam revealing the evolution of the phase singularities.

  2. Matching X-ray beam and detector properties toprotein crystals of different perfection

    PubMed Central

    Nave, Colin

    2014-01-01

    An analysis is given of the effect of different beam and detector parameters on the sharpness of recorded diffraction features for macromolecular crystals of different quality. The crystal quality parameters include crystal strain, crystal or mosaic block size and mosaic block misorientation. Calculations are given for instrument parameters such as angular resolution of the detector, beam divergence and wavelength bandpass to be matched to the intrinsic diffraction properties from these crystals with the aim of obtaining the best possible data out of each crystal. Examples are given using typical crystal imperfections obtained from the literature for both room-temperature and cryo-cooled crystals. Possible implications for the choice of X-ray source, beamline design, detector specifications, instrument set-up and data processing are discussed, together with the limitations of the approach. PMID:24763643

  3. Energy-dispersive X-ray diffraction using an annular beam.

    PubMed

    Dicken, A J; Evans, J P O; Rogers, K D; Greenwood, C; Godber, S X; Prokopiou, D; Stone, N; Clement, J G; Lyburn, I; Martin, R M; Zioupos, P

    2015-05-18

    We demonstrate material phase identification by measuring polychromatic diffraction spots from samples at least 20 mm in diameter and up to 10 mm thick with an energy resolving point detector. Within our method an annular X-ray beam in the form of a conical shell is incident with its symmetry axis normal to an extended polycrystalline sample. The detector is configured to receive diffracted flux transmitted through the sample and is positioned on the symmetry axis of the annular beam. We present the experiment data from a range of different materials and demonstrate the acquisition of useful data with sub-second collection times of 0.5 s; equating to 0.15 mAs. Our technique should be highly relevant in fields that demand rapid analytical methods such as medicine, security screening and non-destructive testing. PMID:26074592

  4. Diffraction with a coherent X-ray beam: dynamics and imaging

    PubMed Central

    Livet, Frédéric

    2007-01-01

    Methods for carrying out coherent X-ray scattering experiments are reviewed. The brilliance of the available synchrotron sources, the characteristics of the existing optics, the various ways of obtaining a beam of controlled coherence properties and the detectors used are summarized. Applications in the study of the dynamics of speckle patterns are described. In the case of soft condensed matter, the movement of inclusions like fillers in polymers or colloidal particles can be observed and these can reflect polymer or liquid-crystal fluctuations. In hard condensed-matter problems, like phase transitions, charge-density waves or phasons in quasicrystals, the study of speckle fluctuations provides new time-resolved methods. In the domain of lensless imaging, the coherent beam gives the modulus of the sample Fourier transform. If oversampling conditions are fulfilled, the phase can be obtained and the image in the direct space can be reconstructed. The forthcoming improvements of all these techniques are discussed. PMID:17301470

  5. Fast-electron refluxing effects on anisotropic hard-x-ray emission from intense laser-plasma interactions.

    PubMed

    McKeever, K; Makita, M; Nersisyan, G; Dzelzainis, T; White, S; Kettle, B; Dromey, B; Zepf, M; Sarri, G; Doria, D; Ahmed, H; Lewis, C L S; Riley, D; Robinson, A P L

    2015-03-01

    Fast-electron generation and dynamics, including electron refluxing, is at the core of understanding high-intensity laser-plasma interactions. This field is itself of strong relevance to fast ignition fusion and the development of new short-pulse, intense, x-ray, γ-ray, and particle sources. In this paper, we describe experiments that explicitly link fast-electron refluxing and anisotropy in hard-x-ray emission. We find the anisotropy in x-ray emission to be strongly correlated to the suppression of refluxing. In contrast to some previous work, the peak of emission is directly along the rear normal to the target rather than along either the incident laser direction or the specular reflection direction. PMID:25871224

  6. 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.

  7. Nonlinear increase of X-ray intensities from thin foils irradiated with a 200 TW femtosecond laser

    DOE PAGESBeta

    Faenov, A. Ya.; Colgan, J.; Hansen, S. B.; Zhidkov, A.; Pikuz, T. A.; Nishiuchi, M.; Pikuz, S. A.; Skobelev, I. Yu.; Abdallah, J.; Sakaki, H.; et al

    2015-09-02

    We report, for the first time, that the energy of femtosecond optical laser pulses, E, with relativistic intensities I > 1021 W/cm2 is efficiently converted to X-ray radiation, which is emitted by “hot” electron component in collision-less processes and heats the solid density plasma periphery. As shown by direct high-resolution spectroscopic measurements X-ray radiation from plasma periphery exhibits unusual non-linear growth ~E4–5 of its power. The non-linear power growth occurs far earlier than the known regime when the radiation reaction dominates particle motion (RDR). Nevertheless, the radiation is shown to dominate the kinetics of the plasma periphery, changing in thismore » regime (now labeled RDKR) the physical picture of the laser plasma interaction. Although in the experiments reported here we demonstrated by observation of KK hollow ions that X-ray intensities in the keV range exceeds ~1017 W/cm2, there is no theoretical limit of the radiation power. Therefore, such powerful X-ray sources can produce and probe exotic material states with high densities and multiple inner-shell electron excitations even for higher Z elements. As a result, femtosecond laser-produced plasmas may thus provide unique ultra-bright X-ray sources, for future studies of matter in extreme conditions, material science studies, and radiography of biological systems.« less

  8. Nonlinear increase of X-ray intensities from thin foils irradiated with a 200 TW femtosecond laser

    PubMed Central

    Faenov, A. Ya.; Colgan, J.; Hansen, S. B.; Zhidkov, A.; Pikuz, T. A.; Nishiuchi, M.; Pikuz, S. A.; Skobelev, I. Yu.; Abdallah, J.; Sakaki, H.; Sagisaka, A.; Pirozhkov, A. S.; Ogura, K.; Fukuda, Y.; Kanasaki, M.; Hasegawa, N.; Nishikino, M.; Kando, M.; Watanabe, Y.; Kawachi, T.; Masuda, S.; Hosokai, T.; Kodama, R.; Kondo, K.

    2015-01-01

    We report, for the first time, that the energy of femtosecond optical laser pulses, E, with relativistic intensities I > 1021  W/cm2 is efficiently converted to X-ray radiation, which is emitted by “hot” electron component in collision-less processes and heats the solid density plasma periphery. As shown by direct high-resolution spectroscopic measurements X-ray radiation from plasma periphery exhibits unusual non-linear growth ~E4–5 of its power. The non-linear power growth occurs far earlier than the known regime when the radiation reaction dominates particle motion (RDR). Nevertheless, the radiation is shown to dominate the kinetics of the plasma periphery, changing in this regime (now labeled RDKR) the physical picture of the laser plasma interaction. Although in the experiments reported here we demonstrated by observation of KK hollow ions that X-ray intensities in the keV range exceeds ~1017  W/cm2, there is no theoretical limit of the radiation power. Therefore, such powerful X-ray sources can produce and probe exotic material states with high densities and multiple inner-shell electron excitations even for higher Z elements. Femtosecond laser-produced plasmas may thus provide unique ultra-bright X-ray sources, for future studies of matter in extreme conditions, material science studies, and radiography of biological systems. PMID:26330230

  9. Nonlinear increase of X-ray intensities from thin foils irradiated with a 200 TW femtosecond laser.

    PubMed

    Faenov, A Ya; Colgan, J; Hansen, S B; Zhidkov, A; Pikuz, T A; Nishiuchi, M; Pikuz, S A; Skobelev, I Yu; Abdallah, J; Sakaki, H; Sagisaka, A; Pirozhkov, A S; Ogura, K; Fukuda, Y; Kanasaki, M; Hasegawa, N; Nishikino, M; Kando, M; Watanabe, Y; Kawachi, T; Masuda, S; Hosokai, T; Kodama, R; Kondo, K

    2015-01-01

    We report, for the first time, that the energy of femtosecond optical laser pulses, E, with relativistic intensities I?>?10(21)??W/cm(2) is efficiently converted to X-ray radiation, which is emitted by "hot" electron component in collision-less processes and heats the solid density plasma periphery. As shown by direct high-resolution spectroscopic measurements X-ray radiation from plasma periphery exhibits unusual non-linear growth ~E(4-5) of its power. The non-linear power growth occurs far earlier than the known regime when the radiation reaction dominates particle motion (RDR). Nevertheless, the radiation is shown to dominate the kinetics of the plasma periphery, changing in this regime (now labeled RDKR) the physical picture of the laser plasma interaction. Although in the experiments reported here we demonstrated by observation of KK hollow ions that X-ray intensities in the keV range exceeds ~10(17)??W/cm(2), there is no theoretical limit of the radiation power. Therefore, such powerful X-ray sources can produce and probe exotic material states with high densities and multiple inner-shell electron excitations even for higher Z elements. Femtosecond laser-produced plasmas may thus provide unique ultra-bright X-ray sources, for future studies of matter in extreme conditions, material science studies, and radiography of biological systems. PMID:26330230

  10. Nonlinear increase of X-ray intensities from thin foils irradiated with a 200 TW femtosecond laser

    NASA Astrophysics Data System (ADS)

    Faenov, A. Ya.; Colgan, J.; Hansen, S. B.; Zhidkov, A.; Pikuz, T. A.; Nishiuchi, M.; Pikuz, S. A.; Skobelev, I. Yu.; Abdallah, J.; Sakaki, H.; Sagisaka, A.; Pirozhkov, A. S.; Ogura, K.; Fukuda, Y.; Kanasaki, M.; Hasegawa, N.; Nishikino, M.; Kando, M.; Watanabe, Y.; Kawachi, T.; Masuda, S.; Hosokai, T.; Kodama, R.; Kondo, K.

    2015-09-01

    We report, for the first time, that the energy of femtosecond optical laser pulses, E, with relativistic intensities I?>?1021??W/cm2 is efficiently converted to X-ray radiation, which is emitted by hot electron component in collision-less processes and heats the solid density plasma periphery. As shown by direct high-resolution spectroscopic measurements X-ray radiation from plasma periphery exhibits unusual non-linear growth ~E4-5 of its power. The non-linear power growth occurs far earlier than the known regime when the radiation reaction dominates particle motion (RDR). Nevertheless, the radiation is shown to dominate the kinetics of the plasma periphery, changing in this regime (now labeled RDKR) the physical picture of the laser plasma interaction. Although in the experiments reported here we demonstrated by observation of KK hollow ions that X-ray intensities in the keV range exceeds ~1017??W/cm2, there is no theoretical limit of the radiation power. Therefore, such powerful X-ray sources can produce and probe exotic material states with high densities and multiple inner-shell electron excitations even for higher Z elements. Femtosecond laser-produced plasmas may thus provide unique ultra-bright X-ray sources, for future studies of matter in extreme conditions, material science studies, and radiography of biological systems.

  11. Nonlinear increase of X-ray intensities from thin foils irradiated with a 200 TW femtosecond laser

    SciTech Connect

    Faenov, A. Ya.; Colgan, J.; Hansen, S. B.; Zhidkov, A.; Pikuz, T. A.; Nishiuchi, M.; Pikuz, S. A.; Skobelev, I. Yu.; Abdallah, J.; Sakaki, H.; Sagisaka, A.; Pirozhkov, A. S.; Ogura, K.; Fukuda, Y.; Kanasaki, M.; Hasegawa, N.; Nishikino, M.; Kando, M.; Watanabe, Y.; Kawachi, T.; Masuda, S.; Hosokai, T.; Kodama, R.; Kondo, K.

    2015-09-02

    We report, for the first time, that the energy of femtosecond optical laser pulses, E, with relativistic intensities I > 1021 W/cm2 is efficiently converted to X-ray radiation, which is emitted by “hot” electron component in collision-less processes and heats the solid density plasma periphery. As shown by direct high-resolution spectroscopic measurements X-ray radiation from plasma periphery exhibits unusual non-linear growth ~E4–5 of its power. The non-linear power growth occurs far earlier than the known regime when the radiation reaction dominates particle motion (RDR). Nevertheless, the radiation is shown to dominate the kinetics of the plasma periphery, changing in this regime (now labeled RDKR) the physical picture of the laser plasma interaction. Although in the experiments reported here we demonstrated by observation of KK hollow ions that X-ray intensities in the keV range exceeds ~1017 W/cm2, there is no theoretical limit of the radiation power. Therefore, such powerful X-ray sources can produce and probe exotic material states with high densities and multiple inner-shell electron excitations even for higher Z elements. As a result, femtosecond laser-produced plasmas may thus provide unique ultra-bright X-ray sources, for future studies of matter in extreme conditions, material science studies, and radiography of biological systems.

  12. Absolute x-ray dosimetry on a synchrotron medical beam line with a graphite calorimeter

    SciTech Connect

    Harty, P. D. Ramanathan, G.; Butler, D. J.; Johnston, P. N.; Lye, J. E.; Hall, C. J.; Stevenson, A. W.

    2014-05-15

    Purpose: The absolute dose rate of the Imaging and Medical Beamline (IMBL) on the Australian Synchrotron was measured with a graphite calorimeter. The calorimetry results were compared to measurements from the existing free-air chamber, to provide a robust determination of the absolute dose in the synchrotron beam and provide confidence in the first implementation of a graphite calorimeter on a synchrotron medical beam line. Methods: The graphite calorimeter has a core which rises in temperature when irradiated by the beam. A collimated x-ray beam from the synchrotron with well-defined edges was used to partially irradiate the core. Two filtration sets were used, one corresponding to an average beam energy of about 80 keV, with dose rate about 50 Gy/s, and the second filtration set corresponding to average beam energy of 90 keV, with dose rate about 20 Gy/s. The temperature rise from this beam was measured by a calibrated thermistor embedded in the core which was then converted to absorbed dose to graphite by multiplying the rise in temperature by the specific heat capacity for graphite and the ratio of cross-sectional areas of the core and beam. Conversion of the measured absorbed dose to graphite to absorbed dose to water was achieved using Monte Carlo calculations with the EGSnrc code. The air kerma measurements from the free-air chamber were converted to absorbed dose to water using the AAPM TG-61 protocol. Results: Absolute measurements of the IMBL dose rate were made using the graphite calorimeter and compared to measurements with the free-air chamber. The measurements were at three different depths in graphite and two different filtrations. The calorimetry measurements at depths in graphite show agreement within 1% with free-air chamber measurements, when converted to absorbed dose to water. The calorimetry at the surface and free-air chamber results show agreement of order 3% when converted to absorbed dose to water. The combined standard uncertainty is 3.9%. Conclusions: The good agreement of the graphite calorimeter and free-air chamber results indicates that both devices are performing as expected. Further investigations at higher dose rates than 50 Gy/s are planned. At higher dose rates, recombination effects for the free-air chamber are much higher and expected to lead to much larger uncertainties. Since the graphite calorimeter does not have problems associated with dose rate, it is an appropriate primary standard detector for the synchrotron IMBL x rays and is the more accurate dosimeter for the higher dose rates expected in radiotherapy applications.

  13. Upgrade of the thirty-meter x-ray pencil beam line at the Institute of Space and Astronautical Science

    NASA Astrophysics Data System (ADS)

    Hayashi, Takayuki; Sato, Toshiki; Tomikawa, Kazuki; Kikuchi, Naomichi; Sato, Takuro; Iizuka, Ryo; Maeda, Yoshitomo; Ishida, Manabu

    2014-07-01

    The thirty-meter X-ray pencil beam line at the Institute of Space and Astronautical Science (ISAS) was utilized for ground-based calibrations of X-ray telescopes (XRTs) onboard the ASTRO-D, the ASTRO-E and the ASTRO- E2 satellites. Recent upsizing or downsizing of XRT required upgrade of the ISAS beam line. We replaced a vacuum chamber in which the stages had been installed by a new cylindrical chamber whose diameter and length are 1.8 m and 11.3 m, respectively. Stages on which a telescope and detectors had been mounted were also replaced. At same time, a new CCD consists of 12401152 pixels whose size are 22.522.5 ?m was introduced. The detector stage can be moved along the X-ray beam in the vacuum chamber, which allows us to change the distance between the sample and the detectors from 0.7 m to 9 m. The two stages can move in at least 500500 mm2 of square in the plane normal to the X-ray beam. The pitching of some moving axes are measured at 60 arcsec at most. The others are no more than about 30 arcsec. From April 2013, the ASTRO-H Soft X-ray telescopes (SXTs) have been calibrated at the new ISAS beam line.

  14. Intensity-modulated x-ray (IMXT) versus proton (IMPT) therapy for theragnostic hypoxia-based dose painting

    NASA Astrophysics Data System (ADS)

    Flynn, Ryan T.; Bowen, Stephen R.; Bentzen, Søren M.; Rockwell Mackie, T.; Jeraj, Robert

    2008-08-01

    In this work the abilities of intensity-modulated x-ray therapy (IMXT) and intensity-modulated proton therapy (IMPT) to deliver boosts based on theragnostic imaging were assessed. Theragnostic imaging is the use of functional or molecular imaging data for prescribing radiation dose distributions. Distal gradient tracking, an IMPT method designed for the delivery of non-uniform dose distributions, was assessed. Dose prescriptions for a hypoxic region in a head and neck squamous cell carcinoma patient were designed to either uniformly boost the region or redistribute the dose based on positron emission tomography (PET) images of the 61Cu(II)-diacetyl-bis(N4-methylthiosemicarbazone) (61Cu-ATSM) hypoxia surrogate. Treatment plans for the prescriptions were created for four different delivery methods: IMXT delivered with step-and-shoot and with helical tomotherapy, and IMPT delivered with spot scanning and distal gradient tracking. IMXT and IMPT delivered comparable dose distributions within the boost region for both uniform and redistributed theragnostic boosts. Normal tissue integral dose was lower by a factor of up to 3 for IMPT relative to the IMXT. For all delivery methods, the mean dose to the nearby organs at risk changed by less than 2 Gy for redistributed versus uniform boosts. The distal gradient tracking method resulted in comparable plans to the spot scanning method while reducing the number of proton beam spots by a factor of over 3.

  15. Intensity modulated x-ray (IMXT) vs. proton (IMPT) therapy for theragnostic hypoxia-based dose painting

    PubMed Central

    Flynn, Ryan T; Bowen, Stephen R; Bentzen, Soren M; Mackie, T Rockwell; Jeraj, Robert

    2009-01-01

    In this work the abilities of intensity modulated x-ray therapy (IMXT) and intensity modulated proton therapy (IMPT) to deliver boosts based on theragnostic imaging were assessed. Theragnostic imaging is the use of functional or molecular imaging data for prescribing radiation dose distributions. Distal gradient tracking, a new IMPT method designed for the delivery of non-uniform dose distributions, was assessed. Dose prescriptions for a hypoxic region in a head and neck squamous cell carcinoma patient were designed to either uniformly boost the region or redistribute the dose based on positron emission tomography (PET) images of the 61Cu(II)-diacetyl-bis(N4-methylthiosemicarbazone) (61Cu-ATSM) hypoxia surrogate. Treatment plans for the prescriptions were created for four different delivery methods: IMXT delivered with step-and-shoot and with helical tomotherapy, and IMPT delivered with spot scanning and distal gradient tracking. IMXT and IMPT delivered comparable dose distributions within the boost region for both uniform and redistributed theragnostic boosts. Normal tissue integral dose was lower by a factor of up to three for IMPT relative to the IMXT. For all delivery methods, the mean dose to the nearby organs at risk changed by less than 2 Gy for redistributed versus uniform boosts. The distal gradient tracking method resulted in comparable plans to the spot scanning method while reducing the number of proton beam spots by a factor of over three. PMID:18635895

  16. Beam characterization of a lab bench cold cathode ultra-soft X-ray generator

    NASA Astrophysics Data System (ADS)

    Ounoughi, N.; Mavon, C.; Belafrites, A.; Groetz, J.-E.; Fromm, M.

    2013-06-01

    The aim of this work is to characterize the Ultra Soft X-ray (USX, 1.5 keV, Al K?) photon beam of a customized lab bench cold cathode generator. Within this generator, the electron beam is slowed down in a thin aluminium foil (16 ?m) supported by an easily exchangeable anode. It is shown that the thickness of the foil and the anode configuration determine the spatial distribution and the fluence rate of the photon beam, whereas accelerating voltage determines both fluence rate and energy spectrum feature. It is shown also that under specific operation parameters (i.e. accelerating voltage), a Gaussian energy distribution of the beam can be generated which is centred on the energy of the Al K? line (1.5 keV). Dosimetric films of GAFCHROMIC HD-810 were used to estimate the photon fluence rate distribution of the beam. Its variation, when the generator acts as a monoenergetic source, was characterized with the two different configurations of the anode assembly. Finally, it is verified that the anode assembly consisting in a flat washer, on which the aluminium foil is set, acts as a simple point-source.

  17. A new generation of detectors for scanning x-ray beam imaging systems

    NASA Astrophysics Data System (ADS)

    Rommel, J. Martin

    2016-01-01

    Scanning x-ray beam imaging systems were first developed by American Science and Engineering, Inc. (AS&E) in the early 1970s [1]. Since then, these systems have found a wide range of applications in security inspection and non-destructive testing. Large-area detectors are most frequently used to collect backscattered radiation but smaller transmission detectors are also employed for selected applications. Until recently, only two basic detector designs have been used: large scintillator blocks with attached photomultiplier tubes (PMTs) or large-volume light-sealed boxes, lined with scintillating screens and port windows for PMTs. In both cases, the detectors have required considerable depth to provide acceptable light collection efficiency. A new design recently developed by AS&E relies on wavelength shifting fibres (WSF) for light collection. For the first time, this approach enables the construction of thin large-area detectors. Stacking layers of WSF ribbons and scintillating screens in varying combinations enables optimization of the detection efficiency for different applications. Taking separate readings from different layers provides an energy-sensitive signal combination. Energy sensitivity can be improved further by adding filtration between the signal channels. Several prototype configurations have been built and characterized for both backscatter and transmission imaging. A WSF-based detector has been commercialized for a transmission x-ray imaging application.

  18. Charge exchange measurements with an x-ray calorimeter at an electron beam ion trap

    NASA Astrophysics Data System (ADS)

    Leutenegger, Maurice A.; Betancourt-Martinez, Gabriele L.; Beiersdorfer, Peter; Brown, Gregory V.; Kelley, Richard L.; Kilbourne, Caroline A.; Porter, F. Scott

    2013-09-01

    We present K-shell x-ray spectra of highly ionized Mg acquired with the EBIT calorimeter spectrometer at a resolution of 4.5 eV in charge exchange recombination experiments using the LLNL EBIT-I electron beam ion trap. We measured the Doppler width of Mg11+ Lyα in the same experiments using a high resolution crystal spectrometer, giving an estimate of the ion temperature. We find hardness ratios for Mg11+ ranging from 0.6 to 1.6, depending on the neutral gas target. In most of the experiments, the ion temperature was ˜ 10-15 eV amu-1, indicating that the variations in hardness ratio are intrinsic to the choice of neutral target gas, and are not simply a consequence of variations in the collision velocity resulting from evaporative cooling of the trapped ions. The spectral variations show that high resolution x-ray spectroscopy is highly diagnostic of charge exchange reactions, but requires well-developed theory to interpret.

  19. X-ray diffraction from bone employing annular and semi-annular beams

    NASA Astrophysics Data System (ADS)

    Dicken, A. J.; Evans, J. P. O.; Rogers, K. D.; Stone, N.; Greenwood, C.; Godber, S. X.; Prokopiou, D.; Clement, J. G.; Lyburn, I. D.; Martin, R. M.; Zioupos, P.

    2015-08-01

    There is a compelling need for accurate, low cost diagnostics to identify osteo-tissues that are associated with a high risk of fracture within an individual. To satisfy this requirement the quantification of bone characteristics such as bone quality need to exceed that provided currently by densitometry. Bone mineral chemistry and microstructure can be determined from coherent x-ray scatter signatures of bone specimens. Therefore, if these signatures can be measured, in vivo, to an appropriate accuracy it should be possible by extending terms within a fracture risk model to improve fracture risk prediction. In this preliminary study we present an examination of a new x-ray diffraction technique that employs hollow annular and semi-annular beams to measure aspects of bone quality. We present diffractograms obtained with our approach from ex vivo bone specimens at Mo K? and W K? energies. Primary data is parameterized to provide estimates of bone characteristics and to indicate the precision with which these can be determined.

  20. Strict X-ray beam collimation for facial bones examination can increase lens exposure

    PubMed Central

    Powys, R; Robinson, J; Kench, P L; Ryan, J; Brennan, P C

    2012-01-01

    Objectives It is well accepted that collimation is a cost-effective dose-reducing tool for X-ray examinations. This phantom-based study investigated the impact of X-ray beam collimation on radiation dose to the lenses of the eyes and thyroid along with the effect on image quality in facial bone radiography. Methods A three-view series (occipitomental, occipitomental 30 and lateral) was investigated, and radiation doses to the lenses and thyroid were measured using an Unfors dosemeter. Images were assessed by six experienced observers using a visual grading analysis and a total of 5400 observations were made. Results Strict collimation significantly (p<0.0001) reduced the radiation dose to the lenses of the eyes and thyroid when using a fixed projection-specific exposure. With a variable exposure technique (fixed exit dose, to simulate the behaviour of an automatic exposure control), while strict collimation was again shown to reduce thyroid dose, higher lens doses were demonstrated when compared with larger fields of exposure. Image quality was found to significantly improve using strict collimation, with observer preference being demonstrated using visual grading characteristic curves. Conclusion The complexities of optimising radiographic techniques have been shown and the data presented emphasise the importance of examining dose-reducing strategies in a comprehensive way. PMID:22374279

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

    PubMed

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

    2015-07-28

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

  2. Commercial CMOS image sensors as X-ray imagers and particle beam monitors

    NASA Astrophysics Data System (ADS)

    Castoldi, A.; Guazzoni, C.; Maffessanti, S.; Montemurro, G. V.; Carraresi, L.

    2015-01-01

    CMOS image sensors are widely used in several applications such as mobile handsets webcams and digital cameras among others. Furthermore they are available across a wide range of resolutions with excellent spectral and chromatic responses. In order to fulfill the need of cheap systems as beam monitors and high resolution image sensors for scientific applications we exploited the possibility of using commercial CMOS image sensors as X-rays and proton detectors. Two different sensors have been mounted and tested. An Aptina MT9v034, featuring 752 × 480 pixels, 6μm × 6μm pixel size has been mounted and successfully tested as bi-dimensional beam profile monitor, able to take pictures of the incoming proton bunches at the DeFEL beamline (1-6 MeV pulsed proton beam) of the LaBeC of INFN in Florence. The naked sensor is able to successfully detect the interactions of the single protons. The sensor point-spread-function (PSF) has been qualified with 1MeV protons and is equal to one pixel (6 mm) r.m.s. in both directions. A second sensor MT9M032, featuring 1472 × 1096 pixels, 2.2 × 2.2 μm pixel size has been mounted on a dedicated board as high-resolution imager to be used in X-ray imaging experiments with table-top generators. In order to ease and simplify the data transfer and the image acquisition the system is controlled by a dedicated micro-processor board (DM3730 1GHz SoC ARM Cortex-A8) on which a modified LINUX kernel has been implemented. The paper presents the architecture of the sensor systems and the results of the experimental measurements.

  3. Nanoscale radiation transport and clinical beam modeling for gold nanoparticle dose enhanced radiotherapy (GNPT) using X-rays.

    PubMed

    Zygmanski, Piotr; Sajo, Erno

    2016-03-01

    We review radiation transport and clinical beam modelling for gold nanoparticle dose-enhanced radiotherapy using X-rays. We focus on the nanoscale radiation transport and its relation to macroscopic dosimetry for monoenergetic and clinical beams. Among other aspects, we discuss Monte Carlo and deterministic methods and their applications to predicting dose enhancement using various metrics. PMID:26642305

  4. Evaluation of soft x-ray average recombination coefficient and average charge for metallic impurities in beam-heated plasmas

    SciTech Connect

    Sesnic, S.S.; Bitter, M.; Hill, K.W.; Hiroe, S.; Hulse, R.; Shimada, M.; Stratton, B.; von Goeler, S.

    1986-05-01

    The soft x-ray continuum radiation in TFTR low density neutral beam discharges can be much lower than its theoretical value obtained by assuming a corona equilibrium. This reduced continuum radiation is caused by an ionization equilibrium shift toward lower states, which strongly changes the value of the average recombination coefficient of metallic impurities anti ..gamma.., even for only slight changes in the average charge, anti Z. The primary agent for this shift is the charge exchange between the highly ionized impurity ions and the neutral hydrogen, rather than impurity transport, because the central density of the neutral hydrogen is strongly enhanced at lower plasma densities with intense beam injection. In the extreme case of low density, high neutral beam power TFTR operation (energetic ion mode) the reduction in anti ..gamma.. can be as much as one-half to two-thirds. We calculate the parametric dependence of anti ..gamma.. and anti Z for Ti, Cr, Fe, and Ni impurities on neutral density (equivalent to beam power), electron temperature, and electron density. These values are obtained by using either a one-dimensional impurity transport code (MIST) or a zero-dimensional code with a finite particle confinement time. As an example, we show the variation of anti ..gamma.. and anti Z in different TFTR discharges.

  5. Chemical Environment Effects on K[beta]/K[alpha] Intensity Ratio: An X-Ray Fluorescence Experiment on Periodic Trends

    ERIC Educational Resources Information Center

    Durham, Chaney R.; Chase, Jeffery M.; Nivens, Delana A.; Baird, William H.; Padgett, Clifford W.

    2011-01-01

    X-ray fluorescence (XRF) data from an energy-dispersive XRF instrument were used to investigate the chlorine K[alpha] and K[beta] peaks in several group 1 salts. The ratio of the peak intensity is sensitive to the local chemical environment of the chlorine atoms studied in this experiment and it shows a periodic trend for these salts. (Contains 1

  6. A study on the use of Gafchromic EBT3 film for output factor measurements in kilovoltage X-ray beams.

    PubMed

    Gill, Simran; Hill, Robin

    2013-12-01

    Relative output factors are used in radiation therapy for treatment planning purposes including treatments using kilovoltage X-ray beams. The output factor is the relative dose output for a particular applicator relative to a reference applicator. Due to the differences in the scatter contribution from the inside of an applicator, it is more accurate if output factors are measured for all combinations of X-ray beam energy and applicator. Previously published papers and various kilovoltage X-ray beam dosimetry protocols have discussed the validity of using various cylindrical and parallel plate ionization chambers for relative output factor measurements. In this work, we evaluated the suitability of Gafchromic EBT3 film for the determination of output factors for kilovoltage X-ray beams. Output factors were measured with Gafchromic EBT3 film for beam qualities of 50, 75, 100 and 125kVp and applicator sizes of 2, 3, 4cm diameter, 8נ8 and 12נ12cm(2) square applicators. The film read out was performed with a flatbed EPSON Expression10000XL scanner. The measured data was compared with benchmark data from measurements using an Advanced Markus ionisation chamber as well as comparing with ratios of published backscatter factor values. The agreement between output factors measured with EBT3 film and the ionisation chamber was generally better than 2%, with the largest difference of 3.3% occurring for the 2cm diameter field with the 50kVp X-ray beam. These differences were consistent with the estimated total uncertainty in the measurements as calculated by the ISO GUM. The agreement between the output factors measured with film and the published BSFs was generally better than 5% but differences of up to 12% occurred for the smallest field size. The results demonstrate that Gafchromic EBT3 film is a suitable dosimeter for output factor measurements of kilovoltage X-ray beams. PMID:24264224

  7. Comparison of SOFC Cathode Microstructure Quantified using X-ray Nanotomography and Focused Ioni Beam-scanning Electron Microscopy

    SciTech Connect

    G Nelson; W Harris; J Lombardo; J Izzo Jr.; W Chiu; P Tanasini; M Cantoni; J Van herle; C Comninellis; et al.

    2011-12-31

    X-ray nanotomography and focused ion beam scanning electron microscopy (FIB-SEM) have been applied to investigate the complex 3D microstructure of solid oxide fuel cell (SOFC) electrodes at spatial resolutions of 45 nm and below. The application of near edge differential absorption for x-ray nanotomography and energy selected backscatter detection for FIB-SEM enable elemental mapping within the microstructure. Using these methods, non-destructive 3D x-ray imaging and FIB-SEM serial sectioning have been applied to compare three-dimensional elemental mapping of the LSM, YSZ, and pore phases in the SOFC cathode microstructure. The microstructural characterization of an SOFC cathode is reported based on these measurements. The results presented demonstrate the viability of x-ray nanotomography as a quantitative characterization technique and provide key insights into the SOFC cathode microstructure.

  8. Comparison of SOFC Cathode Microstructure Quantified using X-ray Nanotomography and Focused Ion Beam - Scanning Electron Microscopy

    SciTech Connect

    Nelson, George J.; Harris, William H.; Lombardo, Jeffrey J.; Izzo, Jr., John R.; Chiu, W. K. S.; Tanasini, Pietro; Cantoni, Marco; Van herle, Jan; Comninellis, Christos; Andrews, Joy C.; Liu, Yijin; Pianetta, Piero; Chu, Yong

    2011-03-24

    X-ray nanotomography and focused ion beam scanning electron microscopy (FIB-SEM) have been applied to investigate the complex 3D microstructure of solid oxide fuel cell (SOFC) electrodes at spatial resolutions of 45 nm and below. The application of near edge differential absorption for x-ray nanotomography and energy selected backscatter detection for FIBSEM enable elemental mapping within the microstructure. Using these methods, non-destructive 3D x-ray imaging and FIBSEM serial sectioning have been applied to compare three-dimensional elemental mapping of the LSM, YSZ, and pore phases in the SOFC cathode microstructure. The microstructural characterization of an SOFC cathode is reported based on these measurements. The results presented demonstrate the viability of x-ray nanotomography as a quantitative characterization technique and provide key insights into the SOFC cathode microstructure.

  9. TEM and x-ray investigation of single crystal-like zirconia films fabricated by dual ion beam deposition

    SciTech Connect

    Ressler, K.G.; Sonnenberg, N.; Cima, M.J.

    1996-12-31

    Single crystal-like yttria-stabilized zirconia (YSZ) thin films have been deposited on amorphous quartz, polycrystalline zirconia, single crystal Si, and Hastelloy substrates using dual ion beam deposition (IBAD). These films are highly crystallographically aligned both normal to and within the film plane. The films are deposited at low substrate temperatures (< 200 C), and the film orientation is substrate independent. 0--20 X-ray diffraction, X-ray rocking curves, X-ray pole figures and X-ray phi scans are used to evaluate the film structure. High resolution cross-sectional TEM is used to examine the evolution of crystallographic film alignment on an amorphous quartz substrate. The data suggest that the evolution of biaxial alignment is nucleation controlled under these conditions.

  10. Signal formation and decay in CdTe x-ray detectors under intense irradiation.

    PubMed

    Jahnke, A; Matz, R

    1999-01-01

    The response of Cd(Zn)Te Schottky and resistive detectors to intense x-rays is investigated in a commercial computed tomography (CT) system to assess their potential for medical diagnostics. To describe their signal height, responsivity, signal-to-noise ratio (SNR), and detective quantum efficiency the devices are modeled as solid-state ionization chambers with spatially varying electric field and charge collection efficiency. The thicknesses and pixel areas of the discrete detector elements are 0.5-2 mm and a few mm2, respectively. The incident spectrum extends from 26 to 120 keV and comprises 10(10) quanta/s cm2. It photogenerates a carrier concentration in the semiconductor that is two to three orders of magnitude above the intrinsic concentration, but remains to a similar extent below the charge densities on the device electrodes. Stable linear operation is achieved with the Schottky-type devices under high bias. Their behavior can be modeled well if negatively charged near-midgap bulk defects with a concentration of 10(11)-10(13) cm-3 are assumed. The bulk defects explain the amount and time constant (about 100 ms) of the detrapping current measured after x-ray pulses (afterglow). To avoid screening by the trapped space charge the bias voltage should exceed 100(V) x [detector thickness/mm]2. Dark currents are of the order of the generation-recombination current, i.e., 300 pA/mm3 detector volume. With proper device design the signal height approaches the theoretical maximum of 0.2 A/W. This high responsivity, however, is not exploited in CT since the SNR is determined here by the incident quantum noise. As a consequence of the detrapping current, the response speed does not meet CT requirements. A medium-term effort for crystal growth appears necessary to achieve the required reduction of the trap density by an order of magnitude. Scintillation based detectors are, therefore, still preferred in fast operating medical diagnostic systems. PMID:9949396

  11. Effect of beam hardening on a visibility-contrast image obtained by X-ray grating interferometry.

    PubMed

    Yashiro, Wataru; Vagovi?, Patrik; Momose, Atsushi

    2015-09-01

    X-ray grating interferometry has been highlighted in the last decade as a multi-modal X-ray phase-imaging technique for providing absorption, differential phase, and visibility-contrast images. It has been mainly reported that the visibility contrast in the visibility-contrast image originates from unresolvable random microstructures. In this paper, we show that the visibility contrast is even reduced by a uniform sample with flat surfaces due to the so-called "beam-hardening effect", which has to be taken into account when X-rays with a continuous spectrum is used. We drive a criterion for determining whether the beam-hardening effect occurs or not, and propose a method for correcting the effect of beam hardening on a visibility-contrast image. PMID:26368446

  12. Kharkov X-ray Generator Based On Compton Scattering

    SciTech Connect

    Shcherbakov, A.; Zelinsky, A.; Mytsykov, A.; Gladkikh, P.; Karnaukhov, I.; Lapshin, V.; Telegin, Y.; Androsov, V.; Bulyak, E.; Botman, J.I.M.; Tatchyn, R.; Lebedev, A.

    2004-05-12

    Nowadays X-ray sources based on storage rings with low beam energy and Compton scattering of intense laser beams are under development in several laboratories. An international cooperative project of an advanced X-ray source of this type at the Kharkov Institute of Physics and Technology (KIPT) is described. The status of the project is reviewed. The design lattice of the storage ring and calculated X-ray beam parameters are presented. The results of numerical simulation carried out for proposed facility show a peak spectral X-ray intensity of about 1014 can be produced.

  13. Excitation-resolved cone-beam x-ray luminescence tomography.

    PubMed

    Liu, Xin; Liao, Qimei; Wang, Hongkai; Yan, Zhuangzhi

    2015-07-01

    Cone-beam x-ray luminescence computed tomography (CB-XLCT), as an emerging imaging technique, plays an important role in in vivo small animal imaging studies. However, CB-XLCT suffers from low-spatial resolution due to the ill-posed nature of reconstruction. We improve the imaging performance of CB-XLCT by using a multiband excitation-resolved imaging scheme combined with principal component analysis. To evaluate the performance of the proposed method, the physical phantom experiment is performed with a custom-made XLCT/XCT imaging system. The experimental results validate the feasibility of the method, where two adjacent nanophosphors (with an edge-to-edge distance of 2.4 mm) can be located. PMID:26160344

  14. Excitation-resolved cone-beam x-ray luminescence tomography

    NASA Astrophysics Data System (ADS)

    Liu, Xin; Liao, Qimei; Wang, Hongkai; Yan, Zhuangzhi

    2015-07-01

    Cone-beam x-ray luminescence computed tomography (CB-XLCT), as an emerging imaging technique, plays an important role in in vivo small animal imaging studies. However, CB-XLCT suffers from low-spatial resolution due to the ill-posed nature of reconstruction. We improve the imaging performance of CB-XLCT by using a multiband excitation-resolved imaging scheme combined with principal component analysis. To evaluate the performance of the proposed method, the physical phantom experiment is performed with a custom-made XLCT/XCT imaging system. The experimental results validate the feasibility of the method, where two adjacent nanophosphors (with an edge-to-edge distance of 2.4 mm) can be located.

  15. Development of X-ray Beam Position Monitors for Superconducting Wiggler

    SciTech Connect

    Kuan, C.-K.; Sheng, I. C.; Lai, W.-Y.; Cheng, Y.-T.; Chen, C.-L.; Hsiung, G.-Y.; Chen, J.-R.

    2010-06-23

    For the development of an X-ray beam position monitor (XBPM) for the superconducting wiggler (SW) at the NSRRC, two XBPM are installed in the SW front end. The blades of the XBPM were manufactured with material of three types; tungsten, Glidcop and aluminium, to test the effect of the material on the performance of the XBPM. These three materials are compared with blades of molybdenum that were previously installed. The vibration and thermal expansion of the pillar of a XBPM affects the position reading of the XBPM. For pillars of XBPM of various designs, each type has a distinct thermal isolating material and is filled with a separate damping material for comparison. The design requirements of these XBPM include high spatial resolution of the monitor and mechanical stability of the structure with a large thermal load. The design, fabrication and measurement results are presented here.

  16. Probing transverse coherence of x-ray beam with 2-D phase grating interferometer

    PubMed Central

    Marathe, Shashidhara; Shi, Xianbo; Wojcik, Michael J.; Kujala, Naresh G.; Divan, Ralu; Mancini, Derrick C.; Macrander, Albert T.; Assoufid, Lahsen

    2014-01-01

    Transverse coherence of the x-ray beam from a bending magnet source was studied along multiple directions using a 2-D ?/2 phase grating by measuring interferogram visibilities at different distances behind the grating. These measurements suggest that the preferred measuring orientation of a 2-D checkerboard grating is along the diagonal directions of the square blocks, where the interferograms have higher visibility and are not sensitive to the deviation of the duty cycle of the grating period. These observations are verified by thorough wavefront propagation simulations. The accuracy of the measured coherence values was also validated by the simulation and analytical results obtained from the source parameters. In addition, capability of the technique in probing spatially resolved local transverse coherence is demonstrated. PMID:24977503

  17. Dosimetry of x-ray beams: The measure of the problem

    SciTech Connect

    de Castro, T.M.

    1986-08-01

    This document contains the text of an oral presentation on dosimetry of analytical x-ray equipment presented at the Denver X-Ray Conference. Included are discussions of sources of background radiation, exposure limits from occupational sources, and the relationship of these sources to the high dose source of x-rays found in analytical machines. The mathematical basis of x-ray dosimetry is reviewed in preparation for more detailed notes on personnel dosimetry and the selection of the most appropriate dosimeter for a specific application. The presentation concludes with a discussion common to previous x-ray equipment accidents. 2 refs. (TEM)

  18. Caustic structures in x-ray Compton scattering off electrons driven by a short intense laser pulse

    NASA Astrophysics Data System (ADS)

    Seipt, D.; Surzhykov, A.; Fritzsche, S.; Kämpfer, B.

    2016-02-01

    We study the Compton scattering of x-rays off electrons that are driven by a relativistically intense short optical laser pulse. The frequency spectrum of the laser-assisted Compton radiation shows a broad plateau in the vicinity of the laser-free Compton line due to a nonlinear mixing between x-ray and laser photons. Special emphasis is placed on how the shape of the short assisting laser pulse affects the spectrum of the scattered x-rays. In particular, we observe sharp peak structures in the plateau region, whose number and locations are highly sensitive to the laser pulse shape. These structures are interpreted as spectral caustics by using a semiclassical analysis of the laser-assisted QED matrix element, relating the caustic peak locations to the laser-driven electron motion.

  19. Hot electron and x-ray production from intense laser irradiation of wavelength-scale polystyrene spheres

    SciTech Connect

    Sumeruk, H. A.; Kneip, S.; Symes, D. R.; Churina, I. V.; Belolipetski, A. V.; Dyer, G.; Landry, J.; Bansal, G.; Bernstein, A.; Donnelly, T. D.; Karmakar, A.; Pukhov, A.; Ditmire, T.

    2007-06-15

    Hot electron and x-ray production from solid targets coated with polystyrene-spheres which are irradiated with high-contrast, 100 fs, 400 nm light pulses at intensity up to 2x10{sup 17} W/cm{sup 2} have been studied. The peak hard x-ray signal from uncoated fused silica targets is an order of magnitude smaller than the signal from targets coated with submicron sized spheres. The temperature of the x-rays in the case of sphere-coated targets is twice as hot as that of uncoated glass. A sphere-size scan of the x-ray yield and observation of a peak in both the x-ray production and temperature at a sphere diameter of 0.26 {mu}m, indicate that these results are consistent with Mie enhancements of the laser field at the sphere surface and multipass stochastic heating of the hot electrons in the oscillating laser field. These results also match well with particle-in-cell simulations of the interaction.

  20. Characteristic x-ray emission from undermines plasmas irradiated by ultra-intense lasers

    SciTech Connect

    Niemann, Christoph

    2012-05-05

    Between FY09 and FY11 we have conducted more than a dozen three-week experimental campaigns at high-power laser facilities around the world to investigate laser-channeling through x-ray and optical imaging and the conversion from laser-energy to xrays. We have performed simultaneous two-wavelength x-ray imaging (K-alpha and He-alpha) to distinguish the hot-plasma region (hot-spot) from the laser-produced electrons (K-alpha). In addition, we have initiated a new collaboration with SNL and have performed first shots on the 100 TW beamlet chamber to commission a fast x-ray streak camera to be used to investigate the temporal evolution of our K-alpha sources. We also collaborated on campaigns at the Rutherford Appleton Laboratory (UK) and the LANL Trident laser to employ laser produced x-ray sources for Thomson scattering off dense matter.

  1. A fast white-beam shutter for hard x-ray topography at beamline 1-BM of the Advanced Photon Source

    NASA Astrophysics Data System (ADS)

    Kujala, Naresh; Erdmann, Mark; Goetze, Kurt; Sullivan, Joseph; Huang, Xianrong; Macrander, Albert

    2014-03-01

    Beamline 1-BM at the Advanced Photon Source (APS) delivers a white beam from a bending magnet with very intense x-ray photon flux. One important application of this beamline is white-beam x-ray topography imaging for crystal-based x-ray optics development and for industrial characterization of single crystals and epitaxial materials. Due to the intense photon flux from the third-generation synchrotron source of the APS, the exposure time of the imaging process should be accurately controlled down to the millisecond level. For this purpose we have designed and implemented a fast shutter that is vacuum compatible to 10-8 torr. The aperture is a copper block with a 70 mm horizontal and 5 mm vertical opening and is water cooled. The aperture is moved vertically up and down by means of a linear voice-coil actuator. The aperture's position is controlled using encoder feedback in a servo loop running on an industrial motion controller. A shutter opening response time of 32 milliseconds was measured. In this paper, we describe the shutter mechanics and its associated electronics installed at the 1-BM, and we report example white-beam topographs of diamond type IIa crystals.

  2. High intensity neutrino beams

    NASA Astrophysics Data System (ADS)

    Ichikawa, A. K.

    2015-07-01

    High-intensity proton accelerator complex enabled long baseline neutrino oscillation experiments with a precisely controlled neutrino beam. The beam power so far achieved is a few hundred kW with enourmorous efforts of accelerator physicists and engineers. However, to fully understand the lepton mixing structure, MW-class accelerators are desired. We describe the current intensity-frontier high-energy proton accelerators, their plans to go beyond and technical challenges in the neutrino beamline facilities.

  3. Investigation of the applicability of a special parallel-plate ionization chamber for x-ray beam dosimetry

    NASA Astrophysics Data System (ADS)

    Perini, Ana P.; P. Neves, Lucio; E. Caldas, Linda V.

    2014-02-01

    Diagnostic x-rays are the greatest source of exposition to ionizing radiation of the population worldwide. In order to obtain accurate and lower-cost dosimeters for quality control assurance of medical x-ray facilities, a special ionization chamber was designed at the Calibration Laboratory of the IPEN, for dosimetry in diagnostic radiology beams. For the chamber characterization some tests were undertaken. Monte Carlo simulations were proposed to evaluate the distribution of the deposited energy in the sensitive volume of the ionization chamber and the collecting electrode effect on the chamber response. According to the obtained results, this special ionization chamber presents potential use for dosimetry of conventional diagnostic radiology beams.

  4. Characterizing transverse coherence of an ultra-intense focused X-ray free-electron laser by an extended Youngs experiment

    PubMed Central

    Inoue, Ichiro; Tono, Kensuke; Joti, Yasumasa; Kameshima, Takashi; Ogawa, Kanade; Shinohara, Yuya; Amemiya, Yoshiyuki; Yabashi, Makina

    2015-01-01

    Characterization of transverse coherence is one of the most critical themes for advanced X-ray sources and their applications in many fields of science. However, for hard X-ray free-electron laser (XFEL) sources there is very little knowledge available on their transverse coherence characteristics, despite their extreme importance. This is because the unique characteristics of the sources, such as the ultra-intense nature of XFEL radiation and the shot-by-shot fluctuations in the intensity distribution, make it difficult to apply conventional techniques. Here, an extended Youngs interference experiment using a stream of bimodal gold particles is shown to achieve a direct measurement of the modulus of the complex degree of coherence of XFEL pulses. The use of interference patterns from two differently sized particles enables analysis of the transverse coherence on a single-shot basis without a priori knowledge of the instantaneous intensity ratio at the particles. For a focused X-ray spot as small as 1.8?m (horizontal) 1.3?m (vertical) with an ultrahigh intensity that exceeds 1018?W?cm?2 from the SPring-8 ngstrom Compact free-electron LAser (SACLA), the coherence lengths were estimated to be 1.7??0.2?m (horizontal) and 1.3??0.1?m (vertical). The ratios between the coherence lengths and the focused beam sizes are almost the same in the horizontal and vertical directions, indicating that the transverse coherence properties of unfocused XFEL pulses are isotropic. The experiment presented here enables measurements free from radiation damage and will be readily applicable to the analysis of the transverse coherence of ultra-intense nanometre-sized focused XFEL beams. PMID:26594369

  5. Integration of a broad beam ion source with a high-temperature x-ray diffraction vacuum chamber.

    PubMed

    Manova, D; Bergmann, A; Mndl, S; Neumann, H; Rauschenbach, B

    2012-11-01

    Here, the integration of a low energy, linearly variable ion beam current density, mechanically in situ adjustable broad beam ion source with a high-temperature x-ray diffraction (XRD) vacuum chamber is reported. This allows in situ XRD investigation of phase formation and evolution processes induced by low energy ion implantation. Special care has been taken to an independent adjustment of the ion beam for geometrical directing towards the substrate, a 15 mm small ion source exit aperture to avoid a secondary sputter process of the chamber walls, linearly variable ion current density by using a pulse length modulation (PLM) for the accelerating voltages without changing the ion beam density profile, nearly homogeneous ion beam distribution over the x-ray footprint, together with easily replaceable Kapton() windows for x-rays entry and exit. By combining a position sensitive x-ray detector with this PLM-modulated ion beam, a fast and efficient time resolved investigation of low energy implantation processes is obtained in a compact experimental setup. PMID:23206070

  6. Integration of a broad beam ion source with a high-temperature x-ray diffraction vacuum chamber

    NASA Astrophysics Data System (ADS)

    Manova, D.; Bergmann, A.; Mndl, S.; Neumann, H.; Rauschenbach, B.

    2012-11-01

    Here, the integration of a low energy, linearly variable ion beam current density, mechanically in situ adjustable broad beam ion source with a high-temperature x-ray diffraction (XRD) vacuum chamber is reported. This allows in situ XRD investigation of phase formation and evolution processes induced by low energy ion implantation. Special care has been taken to an independent adjustment of the ion beam for geometrical directing towards the substrate, a 15 mm small ion source exit aperture to avoid a secondary sputter process of the chamber walls, linearly variable ion current density by using a pulse length modulation (PLM) for the accelerating voltages without changing the ion beam density profile, nearly homogeneous ion beam distribution over the x-ray footprint, together with easily replaceable Kapton windows for x-rays entry and exit. By combining a position sensitive x-ray detector with this PLM-modulated ion beam, a fast and efficient time resolved investigation of low energy implantation processes is obtained in a compact experimental setup.

  7. Integration of a broad beam ion source with a high-temperature x-ray diffraction vacuum chamber

    SciTech Connect

    Manova, D.; Bergmann, A.; Maendl, S.; Neumann, H.; Rauschenbach, B.

    2012-11-15

    Here, the integration of a low energy, linearly variable ion beam current density, mechanically in situ adjustable broad beam ion source with a high-temperature x-ray diffraction (XRD) vacuum chamber is reported. This allows in situ XRD investigation of phase formation and evolution processes induced by low energy ion implantation. Special care has been taken to an independent adjustment of the ion beam for geometrical directing towards the substrate, a 15 mm small ion source exit aperture to avoid a secondary sputter process of the chamber walls, linearly variable ion current density by using a pulse length modulation (PLM) for the accelerating voltages without changing the ion beam density profile, nearly homogeneous ion beam distribution over the x-ray footprint, together with easily replaceable Kapton{sup Registered-Sign} windows for x-rays entry and exit. By combining a position sensitive x-ray detector with this PLM-modulated ion beam, a fast and efficient time resolved investigation of low energy implantation processes is obtained in a compact experimental setup.

  8. Beam Dynamics Study of X-Band Linac Driven X-Ray FELS

    SciTech Connect

    Adolphsen, C.; Limborg-Deprey, C.; Raubenheimer, T.O.; Wu, J.; Sun, Y.; /SLAC

    2011-12-13

    Several linac driven X-ray Free Electron Lasers (XFELs) are being developed to provide high brightness photon beams with very short, tunable wavelengths. In this paper, three XFEL configurations are proposed that achieve LCLS-like performance using X-band linac drivers. These linacs are more versatile, efficient and compact than ones using S-band or C-band rf technology. For each of the designs, the overall accelerator layout and the shaping of the bunch longitudinal phase space are described briefly. During the last 40 years, the photon wavelengths from linac driven FELs have been pushed shorter by increasing the electron beam energy and adopting shorter period undulators. Recently, the wavelengths have reached the X-ray range, with FLASH (Free-Electron Laser in Hamburg) and LCLS (Linac Coherent Light Source) successfully providing users with soft and hard X-rays, respectively. FLASH uses a 1.2 GeV L-band (1.3 GHz) superconducting linac driver and can deliver 10-70 fs FWHM long photon pulses in a wavelength range of 44 nm to 4.1 nm. LCLS uses the last third of the SLAC 3 km S-band (2.856 GHz) normal-conducting linac to produce 3.5 GeV to 15 GeV bunches to generate soft and hard X-rays with good spatial coherence at wavelengths from 2.2 nm to 0.12 nm. Newer XFELs (at Spring8 and PSI) use C-band (5.7 GHz) normal-conducting linac drivers, which can sustain higher acceleration gradients, and hence shorten the linac length, and are more efficient at converting rf energy to bunch energy. The X-band (11.4 GHz) rf technology developed for NLC/GLC offers even higher gradients and efficiencies, and the shorter rf wavelength allows more versatility in longitudinal bunch phase space compression and manipulation. In the following sections, three different configurations of X-band linac driven XFELs are described that operate from 6 to 14 GeV. The first (LOW CHARGE DESIGN) has an electron bunch charge of only 10 pC; the second (OPTICS LINEARIZATION DESIGN) is based on optics linearization of the longitudinal phase space in the first stage bunch compressor and can operate with either a high (250 pC) or low (20 pC) bunch charge; and the third (LCLS INJECTOR DESIGN) is similar to LCLS but uses an X-band linac after the first stage bunch compressor at 250 MeV to achieve a final beam energy up to 14 GeV. Compared with LCLS, these X-band linacs are at least a factor of three shorter.

  9. X-ray beam design for multi-energy imaging with charge-integrating detector: A simulation study

    NASA Astrophysics Data System (ADS)

    Baek, Cheol-Ha; Kim, Daehong

    2015-11-01

    Multi-energy X-ray imaging systems have been widely used for clinical examinations. In order to enhance the imaging quality of these X-ray systems, a dual-energy system that can obtain specific information has been developed in order to discriminate different materials. Although the dual-energy system shows reliable performance for clinical applications, it is necessary to improve the method in order to minimize radiation dose, reduce projection error, and increase image contrast. The purpose of this study is to develop a triple energy technique that can discriminate three materials for the purpose of enhancing imaging quality and patient safety. The X-ray system tube voltage was varied from 40 to 90 kV, and filters (that can generate three X-ray energies) were installed, consisting of pure elemental materials in foil form (including Al, Cu, I, Ba, Ce, Gd, Er, and W). The X-ray beam was evaluated with respect to mean energy ratio, contrast variation ratio, and exposure efficiency. In order to estimate the performance of the suggested technique, Monte Carlo was conducted, and the results were compared to the photon-counting method. As a result, the density maps of iodine, aluminum, and polymethyl methacrylate (PMMA) using the X-ray beam were more accurate in comparison to that obtained with the photon-counting method. According to the results, the suggested triple energy technique can improve the accuracy of the determination of thickness of density. Moreover, the X-ray beam could reduce unnecessary patient dose.

  10. Study of 18 keV K-? x-ray emission from high intensity femtosecond laser produced plasma

    SciTech Connect

    Arora, V. Naik, P. A.; Chakera, J. A.; Bagchi, S.; Tayyab, M.; Gupta, P. D.

    2014-04-15

    We report an experimental study on the optimization of a laser plasma based x-ray source of ultra-short duration K-? line radiation. The interaction of pulses from a CPA based Ti:sapphire laser (10 TW, 45 fs, 10 Hz) system with magnesium, titanium, iron and copper solid target generates bright 1-8 keV K-? x-ray radiation. The x-ray yield was optimized with the laser pulse duration (at fixed fluence) which is varied in the range of 45 fs to 1.4 ps. It showed a maximum at laser pulse duration of ?740 fs, 420 fs, 350 and 250 fs for Mg (1.3 keV), Ti (4.5 keV), Fe (6.4 keV) and Cu (8.05 keV) respectively. The x-ray yield is observed to be independent of the sign of the chirp. The scaling of the K-? yield (I{sub x} ? I{sub L}{sup ?}) for 45 fs and optimized pulse duration were measured for laser intensities in the region of 3 10{sup 14} 8 10{sup 17}. The x-ray yield shows a much faster scaling exponent ? = 1.5, 2.1, 2.4 and 2.6 for Mg, Ti, Fe and Cu respectively at optimized pulse duration compared to scaling exponent of 0.65, 1.3, 1.5, and 1.7 obtained for 45 fs duration laser pulses. The laser to x-ray energy conversion efficiencies obtained for different target materials are ?{sub Mg} = 1.2 10{sup ?5}, ?{sub Ti} = 3.1 10{sup ?5}, ?{sub Fe} = 2.7 10{sup ?5}, ?{sub Cu} = 1.9 10{sup ?5}. The results have been explained from the efficient generation of optimal energy hot electrons at longer laser pulse duration. The faster scaling observed at optimal pulse duration indicates that the x-ray source is generated at the target surface and saturation of x-ray emission would appear at larger laser fluence. An example of utilization of the source for measurement of shock-wave profiles in a silicon crystal by time resolved x-ray diffraction is also presented.

  11. Cluster beam targets for laser plasma extreme ultraviolet and soft x-ray sources

    DOEpatents

    Kublak, Glenn D.; Richardson, Martin C. (CREOL

    1996-01-01

    Method and apparatus for producing extreme ultra violet (EUV) and soft x-ray radiation from an ultra-low debris plasma source are disclosed. Targets are produced by the free jet expansion of various gases through a temperature controlled nozzle to form molecular clusters. These target clusters are subsequently irradiated with commercially available lasers of moderate intensity (10.sup.11 -10.sup.12 watts/cm.sup.2) to produce a plasma radiating in the region of 0.5 to 100 nanometers. By appropriate adjustment of the experimental conditions the laser focus can be moved 10-30 mm from the nozzle thereby eliminating debris produced by plasma erosion of the nozzle.

  12. Cluster beam targets for laser plasma extreme ultraviolet and soft x-ray sources

    DOEpatents

    Kublak, G.D.; Richardson, M.C.

    1996-11-19

    Method and apparatus for producing extreme ultraviolet (EUV) and soft x-ray radiation from an ultra-low debris plasma source are disclosed. Targets are produced by the free jet expansion of various gases through a temperature controlled nozzle to form molecular clusters. These target clusters are subsequently irradiated with commercially available lasers of moderate intensity (10{sup 11}--10{sup 12} watts/cm{sup 2}) to produce a plasma radiating in the region of 0.5 to 100 nanometers. By appropriate adjustment of the experimental conditions the laser focus can be moved 10--30 mm from the nozzle thereby eliminating debris produced by plasma erosion of the nozzle. 5 figs.

  13. Dependence of Coulomb capture ratio and x-ray intensities on the mesonic-particle energy spectrum

    NASA Astrophysics Data System (ADS)

    Daniel, H.

    1981-09-01

    The dependence of the per-atom capture ratio A(Z1, Z2) and the x-ray intensity pattern on the spectral flux density n(W) of slow mesonic particles in the target is calculated in closed form with a semiclassical theory. The intensity pattern turns out to vary only slightly with n(W) whereas the capture ratio shows a more pronounced dependence. Numerical results are presented.

  14. Multiphoton dissociation of H2S by intense x-ray pulses from the Linac Coherent Light Source FEL

    NASA Astrophysics Data System (ADS)

    Murphy, Brendan; Fang, Li; Hoener, Matthias; Kukk, Edwin; Kanter, Elliot; Bozek, John; Berrah, Nora

    2011-05-01

    We will report on sequential multiphoton ionization of H2S by intense pulses of x-rays from the LCLS free electron laser. Following L-shell excitation, fragmentation of the molecule is observed by Auger electron, photoelectron, and ion time-of-flight spectroscopy. Intensity dependent features in these spectra shed light on the dynamics of the dissociation process. This work is funded by the DOE-SC-BES, Chemical Sciences, Geosciences and Biosciences Division.

  15. Z-pinches as intense x-ray sources for high energy density physics application

    SciTech Connect

    Matzen, M.K.

    1997-02-01

    Fast z-pinch implosions can convert more than 10% of the stored electrical energy in a pulsed-power accelerator into x rays. These x rays are produced when an imploding cylindrical plasma, driven by the magnetic field pressure associated with very large axial currents, stagnates upon the cylindrical axis of symmetry. On the Saturn pulsed-power accelerator at Sandia National Laboratories, for example, currents of 6 to 8 MA with a risetime of less than 50 ns are driven through cylindrically-symmetric loads, producing implosions velocities as high as 100 cm/{mu}s and x-ray energies as high as 500 kJ. The keV component of the resulting x-ray spectrum has been used for many years 8 a radiation source for material response studies. Alternatively, the x-ray output can be thermalized into a near-Planckian x-ray source by containing it within a large cylindrical radiation case. These large volume, long-lived radiation sources have recently been used for ICF-relevant ablator physics experiments as well as astrophysical opacity and radiation-material interaction experiments. Hydromagnetic Rayleigh-Taylor instabilities and cylindrical load symmetry are critical, limiting factors in determining the assembled plasma densities and temperatures, and thus in the x-ray pulse widths that can be produced on these accelerators. In recent experiments on the Saturn accelerator, these implosion nonuniformities have been minimized by using uniform-fill gas puff loads or by using wire arrays with as many a 192 wires. These techniques produced significant improvements in the pinched plasma quality, Zn reproducibility, and x-ray output power. X-ray pulse widths of less than 5 ns and peak powers of 75{+-}10 TW have been achieved with arrays of 120 tungsten wires. These powers represent greater than a factor of three in power amplification over the electrical power of the Saturn n accelerator, and are a record for x-ray powers in the laboratory.

  16. 3D visualization of XFEL beam focusing properties using LiF crystal X-ray detector

    NASA Astrophysics Data System (ADS)

    Pikuz, Tatiana; Faenov, Anatoly; Matsuoka, Takeshi; Matsuyama, Satoshi; Yamauchi, Kazuto; Ozaki, Norimasa; Albertazzi, Bruno; Inubushi, Yuichi; Yabashi, Makina; Tono, Kensuke; Sato, Yuya; Yumoto, Hirokatsu; Ohashi, Haruhiko; Pikuz, Sergei; Grum-Grzhimailo, Alexei N.; Nishikino, Masaharu; Kawachi, Tetsuya; Ishikawa, Tetsuya; Kodama, Ryosuke

    2015-12-01

    Here, we report, that by means of direct irradiation of lithium fluoride a (LiF) crystal, in situ 3D visualization of the SACLA XFEL focused beam profile along the propagation direction is realized, including propagation inside photoluminescence solid matter. High sensitivity and large dynamic range of the LiF crystal detector allowed measurements of the intensity distribution of the beam at distances far from the best focus as well as near the best focus and evaluation of XFEL source size and beam quality factor M2. Our measurements also support the theoretical prediction that for X-ray photons with energies ~10?keV the radius of the generated photoelectron cloud within the LiF crystal reaches about 600?nm before thermalization. The proposed method has a spatial resolution ~?0.42.0??m for photons with energies 614?keV and potentially could be used in a single shot mode for optimization of different focusing systems developed at XFEL and synchrotron facilities.

  17. 3D visualization of XFEL beam focusing properties using LiF crystal X-ray detector.

    PubMed

    Pikuz, Tatiana; Faenov, Anatoly; Matsuoka, Takeshi; Matsuyama, Satoshi; Yamauchi, Kazuto; Ozaki, Norimasa; Albertazzi, Bruno; Inubushi, Yuichi; Yabashi, Makina; Tono, Kensuke; Sato, Yuya; Yumoto, Hirokatsu; Ohashi, Haruhiko; Pikuz, Sergei; Grum-Grzhimailo, Alexei N; Nishikino, Masaharu; Kawachi, Tetsuya; Ishikawa, Tetsuya; Kodama, Ryosuke

    2015-01-01

    Here, we report, that by means of direct irradiation of lithium fluoride a (LiF) crystal, in situ 3D visualization of the SACLA XFEL focused beam profile along the propagation direction is realized, including propagation inside photoluminescence solid matter. High sensitivity and large dynamic range of the LiF crystal detector allowed measurements of the intensity distribution of the beam at distances far from the best focus as well as near the best focus and evaluation of XFEL source size and beam quality factor M(2). Our measurements also support the theoretical prediction that for X-ray photons with energies ~10?keV the radius of the generated photoelectron cloud within the LiF crystal reaches about 600?nm before thermalization. The proposed method has a spatial resolution ~?0.4-2.0??m for photons with energies 6-14?keV and potentially could be used in a single shot mode for optimization of different focusing systems developed at XFEL and synchrotron facilities. PMID:26634431

  18. 3D visualization of XFEL beam focusing properties using LiF crystal X-ray detector

    PubMed Central

    Pikuz, Tatiana; Faenov, Anatoly; Matsuoka, Takeshi; Matsuyama, Satoshi; Yamauchi, Kazuto; Ozaki, Norimasa; Albertazzi, Bruno; Inubushi, Yuichi; Yabashi, Makina; Tono, Kensuke; Sato, Yuya; Yumoto, Hirokatsu; Ohashi, Haruhiko; Pikuz, Sergei; Grum-Grzhimailo, Alexei N.; Nishikino, Masaharu; Kawachi, Tetsuya; Ishikawa, Tetsuya; Kodama, Ryosuke

    2015-01-01

    Here, we report, that by means of direct irradiation of lithium fluoride a (LiF) crystal, in situ 3D visualization of the SACLA XFEL focused beam profile along the propagation direction is realized, including propagation inside photoluminescence solid matter. High sensitivity and large dynamic range of the LiF crystal detector allowed measurements of the intensity distribution of the beam at distances far from the best focus as well as near the best focus and evaluation of XFEL source size and beam quality factor M2. Our measurements also support the theoretical prediction that for X-ray photons with energies ~10 keV the radius of the generated photoelectron cloud within the LiF crystal reaches about 600 nm before thermalization. The proposed method has a spatial resolution ~ 0.4–2.0 μm for photons with energies 6–14 keV and potentially could be used in a single shot mode for optimization of different focusing systems developed at XFEL and synchrotron facilities. PMID:26634431

  19. Beam hardening correction for X-ray computed tomography of heterogeneous natural materials

    NASA Astrophysics Data System (ADS)

    Ketcham, Richard A.; Hanna, Romy D.

    2014-06-01

    We present a new method for correcting beam hardening artifacts in polychromatic X-ray CT data. On most industrial CT systems, software beam-hardening correction employs some variety of linearization, which attempts to transform the polychromatic attenuation data into its monochromatic equivalent prior to image reconstruction. However, determining optimal coefficients for the transform equation is not straightforward, especially if the material is not well known or characterized, as is the usual case when imaging geological materials. Our method uses an iterative optimization algorithm to find a generalized spline-interpolated transform that minimizes artifacts as defined by an expert user. This generality accesses a richer set of linearization functions that may better accommodate the effects of multiple materials in heterogeneous samples. When multiple materials are present in the scan field, there is no single optimal correction, and the solution can vary depending on which aspects of the beam-hardening and other image artifacts the user wants to minimize. For example, the correction can be optimized to maximize the fidelity of the object outline for solid model creation rather than simply to minimize variation of CT numbers within the material. We demonstrate our method on a range of specimens of varying difficulty and complexity, with consistently positive results.

  20. Wide-angle monochromatic x-ray beam shutter: a design study

    SciTech Connect

    Brajuskovic, Bran; Chang, Joseph; Carrera, Frank; Lurio, Laurence; Pelletier, Jean-Francois; Shu, Deming

    2003-10-15

    A novel design of a wide-angle monochromatic x-ray beam shutter is discussed. The shutter is designed as a compact unit capable of providing users with the means of shutting off the beam in secondary beamlines that are at an angle to the primary beamline and to each other. The single-unit design used the fact that all the secondary beamlines will be closed at the same time. The main challenge was to fit the shutter in the limited space of the existing Advanced Photon Source IMMW-CAT hutch. Space limitations led to the change in position of the actuator subassembly as compared to the standard shutter design. Although the actuator subassembly is placed underneath the shutter, fail-safe shutting is achieved by placing tungsten blocks above the beam while the shutter is open and using gravity to close the shutter in case of pneumatic failure. Redundancy required by safety concerns was achieved by duplicating the tungsten block/actuator subunits. Tungsten blocks of uneven length were used to counteract the increase in the center-to-center distance among secondary beamlines due to their angular offset. A special support table was designed to facilitate assembly and adjustability of the shutter position in the available space. To provide a radiation-tight hutch, a non-standard guillotine system was designed. In this paper, the design, specifications and optical ray tracing of the shutter assembly are presented.

  1. Wide-angle monochromatic x-ray beam shutter : a design study.

    SciTech Connect

    Brajuskovic, B.; Chang, J.; Carrera, F.; Lourio, L.; Pelletier, J.F.; Shu, D.

    2002-07-09

    A novel design of a wide-angle monochromatic x-ray beam shutter is discussed. The shutter is designed as a compact unit capable of providing users with the means of shutting off the beam in secondary beamlines that are at an angle to the primary beamline and to each other. The single-unit design used the fact that all the secondary beamlines will be closed at the same time. The main challenge was to fit the shutter in the limited space of the existing Advanced Photon Source IMMW-CAT hutch. Space limitations led to the change in position of the actuator subassembly as compared to the standard shutter design. Although the actuator subassembly is placed underneath the shutter, fail-safe shutting is achieved by placing tungsten blocks above the beam while the shutter is open and using gravity to close the shutter in case of pneumatic failure. Redundancy required by safety concerns was achieved by duplicating the tungsten block/actuator subunits. Tungsten blocks of uneven length were used to counteract the increase in the center-to-center distance among secondary beamlines due to their angular offset. A special support table was designed to facilitate assembly and adjustability of the shutter position in the available space. To provide a radiation-tight hutch, a non-standard guillotine system was designed. In this paper, the design, specifications and optical ray tracing of the shutter assembly are presented.

  2. Charge integrating type position-sensitive proportional chamber for time-resolved measurements using intense X-ray sources

    NASA Astrophysics Data System (ADS)

    Mochiki, Koh-ichi; Hasegawa, Ken-ichi

    1985-02-01

    A position-sensitive detecting system for time-resolved diffraction measurements with very intensive X-ray sources has been developed. It consists of a charge integrating type gas-filled detector, multichannel analog multiplexers, a signal processor and a memory (120 ch.×128 phases×24 bits). The detector is 120 mm long in effective length by 10 mm×10 mm in cross section with a single anode of 20 μm diameter. One of the cathode planes consists of 120 cathode strips with a pitch of 1 mm. The spatial resolution is equal to the pitch under a certain detector current limit. The gas gain is adjustable to an appropriate value according to the X-ray intensity range of interest. For experiments with 8 keV X-ray sources, maximum absorption rates of 9×10 7 photons/s·mm with low applied voltage and minimum absorption rates of about 3 photons/s·mm with high applied voltage can be achieved. This system was applied to a time-resolved X-ray diffraction study on frog muscle using a synchrotron radiation source at the Photon Factory and we could collect diffraction patterns with a time resolution of 10 ms and only 10 stimulations.

  3. Glass capillary optics for making x-ray beams of 0.1 to 50 microns diameter

    SciTech Connect

    Bilderback, Donald H.; Fontes, Ernest

    1997-07-01

    We have fabricated a unique computerized glass puller that can make parabolic or elliptically tapered glass capillaries for microbeam x-ray experiments from hollow glass tubing. We have produced optics that work in a single-bounce imaging mode or in a multi-bounce condensing mode. The imaging-mode capillaries have been used to create 20 to 50 micron diameter x-ray beams at 12 keV that are quite useful for imaging diffraction patterns from tiny bundles of carbon and Kevlar fibers. The condensing-mode capillaries are useful for creating submicron diameter beams and show great promise in x-ray fluorescence applications with femtogram sensitivity for patterned Er and Ti dopants diffused into an optically-active lithium niobate wafer.

  4. Focused ion beam patterned Fe thin films A study by selective area Stokes polarimetry and soft x-Ray microscopy

    SciTech Connect

    Cook, P. J.; Shen, T. H.; Grundy, P. J.; Im, M.-Y.; Fischer, P.; Morton, S. A.; Kilcoyne, A. L. D.

    2010-11-14

    We demonstrate the potential to modify the magnetic behavior and structural properties of ferromagnetic thin films using focused ion beam 'direct-write' lithography. Patterns inspired by the split-ring resonators often used as components in meta-materials were defined upon 15 nm Fe films using a 30 keV Ga{sup +} focused ion beam at a dose of 2 x 10{sup 16} ions cm{sup -2}. Structural, chemical and magnetic changes to the Fe were studied using transmission soft X-ray microscopy at the ALS, Berkeley CA. X-ray absorption spectra showed a 23% reduction in the thickness of the film in the Ga irradiated areas, but no chemical change to the Fe was evident. X-ray images of the magnetic reversal process show domain wall pinning around the implanted areas, resulting in an overall increase in the coercivity of the film. Transmission electron microscopy showed significant grain growth in the implanted regions.

  5. X-ray and gamma-ray intensity measurements in 131I, 166Ho, 198Au and 199Au decays

    NASA Astrophysics Data System (ADS)

    Chand, Bakhshish; Goswamy, Jatinder; Mehta, Devinder; Singh, Nirmal; Trehan, P. N.

    1989-12-01

    Relative intensities of X- and gamma rays emitted in the decays of 131I, 166Ho, 198Au and 199Au have been measured precisely using a set of five detectors: 96.0 cm 3 and 57.1 cm 3 coaxial HPGe detectors, a 28.27 mm 2 × 5.0 mm vertical planar HPGe detector and two 28.27 mm 2 × 5.5 mm Si(Li) detectors. The measured values of X-ray intensities are, in general, in good agreement with the theoretically calculated values. The intensities of different components of K and L X-rays in the above mentioned decays have been measured for the first time.

  6. Speciman holder design improves accuracy of X-ray powder analysis

    NASA Technical Reports Server (NTRS)

    Mack, M.

    1966-01-01

    Specimen holder for X ray diffraction analysis presents the specimen to the incident X rays in a curvature. This permits the use of an X ray beam having a larger divergence angle, the beam intensity is increased, and the statistical accuracy of analysis is improved.

  7. Ultra-short wavelength x-ray system

    DOEpatents

    Umstadter, Donald; He, Fei; Lau, Yue-Ying

    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.

  8. Noise reduction by projection direction dependent diffusion for low dose fan-beam x-ray computed tomography

    NASA Astrophysics Data System (ADS)

    Tang, Shaojie; Mou, Xuanqin; Zhang, Yanbo; Yu, Hengyong

    2011-03-01

    We propose a novel method to reduce the noise in fan-beam computed tomography (CT) imaging. First, the inverse Radon transform is induced for a family of differential expression of projection function. Second, the diffusion partial differential equation (PDE) is generalized from image space to projection space in parallel-beam geometry. Third, the diffusion PDE is further induced from parallel-beam geometry to fan-beam geometry. Finally, the projection direction dependent diffusion is developed to reduce CT noise, which arises from the quantum variation in the low dose exposure of a medical x-ray CT (XCT) system. The proposed noise reduction processes projections iteratively and dependently on x-ray path position, followed by a general CT reconstruction. Numerical simulation studies have demonstrated its feasibility in the noise reduction of low dose fan-beam XCT imaging.

  9. Ground calibrations of the X-ray detector system of the Solar Intensity X-ray Spectrometer (SIXS) on board BepiColombo

    NASA Astrophysics Data System (ADS)

    Huovelin, Juhani; Lehtolainen, Arto; Genzer, Maria; Korpela, Seppo; Esko, Eero; Andersson, Hans

    2014-05-01

    SIXS includes X-ray and particle detector systems for the BepiColombo Mercury Planetary Orbiter (MPO). Its task is to monitor the direct solar X-rays and energetic particles in a wide field of view in the energy range of 1-20 keV (X-rays), 0.1-3 MeV (electrons) and 1-30 MeV (protons). The main purpose of these measurements is to provide quantitative information on the high energy radiation incident on Mercury's surface which causes the X-ray glow of the planet measured by the MIXS instrument. The X-ray and particle measurements of SIXS are also useful for investigations of the solar corona and the magnetosphere of Mercury. The ground calibrations of the X-ray detectors of the SIXS flight model were carried out in the X-ray laboratory of the Helsinki University during May and June 2012. The aim of the ground calibrations was to characterize the performance of the SIXS instrument's three High-Purity Silicon PIN X-ray detectors and verify that they fulfil their scientific performance requirements. The calibrations included the determination of the beginning of life energy resolution at different operational temperatures, determination of the detector's sensitivity within the field of view as a function of the off-axis and roll angles, pile-up tests for determining the speed of the read out electronics, measurements of the low energy threshold of the energy scale, a cross-calibration with the SMART-1 XSM flight spare detector, and the determination of the temperature dependence of the energy scale. An X-ray tube and the detectors' internal Ti coated 55Fe calibration sources were used as primary X-ray sources. In addition, two external fluorescence sources were used as secondary X-ray sources in the determination of the energy resolutions and in the comparison calibration with the SMART-1 XSM. The calibration results show that the detectors fulfill all of the scientific performance requirements. The ground calibration data combined with the instrument house-keeping data, spacecraft attitude data in relation to the Sun, and the in-flight calibration spectra measured during the operations contain all required information for the final analysis of the solar X-ray data.

  10. Mass-energy absorption coefficient and backscatter factor ratios for kilovoltage x-ray beams

    NASA Astrophysics Data System (ADS)

    Ma, C.-M.; Seuntjens, J. P.

    1999-01-01

    For low-energy (up to 150 kV) x-rays, the ratio of mass-energy absorption coefficients for water to air, , and the backscatter factor B are used in the conversion of air kerma, measured free-in-air, to water kerma on the surface of a water phantom. For clinical radiotherapy, similar conversion factors are needed for the determination of the absorbed dose to biological tissues on (or near) the surface of a human body. We have computed the ratios and B factor ratios for different biological tissues including muscle, soft tissue, lung, skin and bone relative to water. The ratios were obtained by integrating the respective mass-energy absorption coefficients over the in-air primary photon spectra. We have also calculated the ratios at different depths in a water phantom in order to convert the measured in-phantom water kerma to the absorbed dose to various biological tissues. The EGS4/DOSIMETER Monte Carlo code system has been used for the simulation of the energy fluence at different depths in a water phantom irradiated by a kilovoltage x-ray beam of variable beam quality (HVL: 0.1 mm Al-5 mm Cu), field size and source-surface distance (SSD). The same code was also used in the calculation of the B factor ratios, soft tissue to water and bone to water. The results show that the B factor for bone differs from the B factor for water by up to 20% for a 100 kV beam (HVL: 2.65 mm Al) with a 100 field. On the other hand, the difference in the B factor between water and soft tissue is insignificant (well within 1% generally). This means that the B factors for water may be directly used to convert the `in-air' water kerma to surface kerma for human soft tissues.

  11. 3D-CT imaging using characteristic X-rays and visible lights produced by ion micro-beam bombardment

    NASA Astrophysics Data System (ADS)

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

    2006-08-01

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

  12. Analytical reconstructions of intensity modulated x-ray phase-contrast imaging of human scale phantoms

    PubMed Central

    Włodarczyk, Bartłomiej; Pietrzak, Jakub

    2015-01-01

    This paper presents analytical approach to modeling of a full planar and volumetric acquisition system with image reconstructions originated from partial illumination x-ray phase-contrast imaging at a human scale using graphics processor units. The model is based on x-ray tracing and wave optics methods to develop a numerical framework for predicting the performance of a preclinical phase-contrast imaging system of a human-scaled phantom. In this study, experimental images of simple numerical phantoms and high resolution anthropomorphic phantoms of head and thorax based on non-uniform rational b-spline shapes (NURBS) prove the correctness of the model. Presented results can be used to simulate the performance of partial illumination x-ray phase-contrast imaging system on various preclinical applications. PMID:26600991

  13. Analytical reconstructions of intensity modulated x-ray phase-contrast imaging of human scale phantoms.

    PubMed

    Włodarczyk, Bartłomiej; Pietrzak, Jakub

    2015-11-01

    This paper presents analytical approach to modeling of a full planar and volumetric acquisition system with image reconstructions originated from partial illumination x-ray phase-contrast imaging at a human scale using graphics processor units. The model is based on x-ray tracing and wave optics methods to develop a numerical framework for predicting the performance of a preclinical phase-contrast imaging system of a human-scaled phantom. In this study, experimental images of simple numerical phantoms and high resolution anthropomorphic phantoms of head and thorax based on non-uniform rational b-spline shapes (NURBS) prove the correctness of the model. Presented results can be used to simulate the performance of partial illumination x-ray phase-contrast imaging system on various preclinical applications. PMID:26600991

  14. Perspectives of ion beam polishing of mandrels for x-ray replication optics

    NASA Astrophysics Data System (ADS)

    Ghigo, Mauro; Citterio, Oberto; Conconi, Paolo; Loi, Ralf; Mazzoleni, Franco

    1995-06-01

    The optical system requirements for high throughput, high resolution, x-ray telescopes for future space missions that foresee the use of a manufacturing process by replica method, demand a tight control of the shape of the mandrels used for the production of the shells. Since the number of mandrels to be manufactured for a project is generally high, it's also important that the technology adopted for the shape control be cost-effective. With the proposed approach, the aluminum-kanigen mandrels are diamond turned and superpolished to the required microroughness. The final figuring is then obtained with the ion-beam polishing technology that allows the fine tuning of the mandrel shape preserving its microroughness. This method has significant advantages over other conventional figuring processes since no physical load is applied to the mandrel and the material removal function generated from the ion source is stable and repeatable, allowing a deterministic final figuring in one or few passes. A computer simulation of the ion-beam polishing of a mandrel has been executed. An evaluation of the effect of the size of the material removal function used, the final surface error, and the working time required have been obtained.

  15. Parameterized algorithms for quantitative differentials in spectrally equivalent medical diagnostic x-ray beams

    SciTech Connect

    Okunade, Akintunde Akangbe

    2005-06-15

    Qualitative and quantitative equivalence of spectra transmitted by two different elemental filters require a good match in terms of shape and size over the entire energy range of 0-150 keV used in medical diagnostic radiology. However, the photoelectric absorptions and Compton scattering involved in the interaction of x rays with matter at these relatively low photon energies differ in a nonuniform manner with energy and atomic number. By careful choice of thicknesses for filter materials with an atomic number between 12 and 39, when compared with aluminum, it is possible to obtain transmitted beams of the same shape (quality) but not of the same size (quantity). In this paper, calculations have been carried out for the matching of the shapes and sizes of beams transmitted through specified thicknesses of aluminium filter and spectrally equivalent thicknesses of other filter materials (different from aluminium) using FORTRAN source codes traceable to the American Association of Physics in Medicine (AAPM), College Park, MD, USA. Parametrized algorithms for the evaluation of quantitative differentials (deficit or surplus) in radiation output (namely, photon fluence, exposure, kerma, energy imparted, absorbed dose, and effective dose) from these transmitted spectrally equivalent beams were developed. These differentials range between 1%, and 4% at 1 mm Al filtration and between 8%, and 25% for filtration of 6 mm Al for different filter materials in comparison with aluminum. Also developed were models for factors for converting measures of photon fluence, exposure-area product, (EAP), and kerma-area product (KAP) to risk related quantities such as energy imparted, absorbed dose, and effective dose from the spectrally equivalent beams. The thicknesses of other filter materials that are spectrally equivalent to given thicknesses of aluminum filter were characterized using polynomial functions. The fact that the use of equivalent spectra in radiological practice can provide means of ranking the differentials in radiographic image quality and stochastic risk is discussed.

  16. Tissue-Sparing Effect of X-ray Microplanar Beams Particulary in the CNS: Is a Bystander Effect Involved?

    SciTech Connect

    Dilmanian,A.; Qu, Y.; Feinendegen, L.; Pena, L.; Bacarian, T.; Henn, F.; Kalef-Ezra, J.; Liu, S.; Zhong, Z.; McDonald, J.

    2007-01-01

    Normal tissues, including the central nervous system, tolerate single exposures to narrow planes of synchrotron-generated x-rays (microplanar beams; microbeams) up to several hundred Gy. The repairs apparently involve the microvasculature and the glial system. We evaluate a hypothesis on the involvement of bystander effects in these repairs.

  17. Tokamak x ray diagnostic instrumentation

    SciTech Connect

    Hill, K.W.; Beiersdorfer, P.; Bitter, M.; Fredrickson, E.; Von Goeler, S.; Hsuan, H.; Johnson, L.C.; Liew, S.L.; McGuire, K.; Pare, V.

    1987-01-01

    Three classes of x-ray diagnostic instruments enable measurement of a variety of tokamak physics parameters from different features of the x-ray emission spectrum. (1) The soft x-ray (1 to 50 keV) pulse-height-analysis (PHA) diagnostic measures impurity concentrations from characteristic line intensities and the continuum enhancement, and measures the electron temperature from the continuum slope. (2) The Bragg x-ray crystal spectrometer (XCS) measures the ion temperature and neutral-beam-induced toroidal rotation velocity from the Doppler broadening and wavelength shift, respectively, of spectral lines of medium-Z impurity ions. Impurity charge state distributions, precise wavelengths, and inner-shell excitation and recombination rates can also be studied. X rays are diffracted and focused by a bent crystal onto a position-sensitive detector. The spectral resolving power E/..delta..E is greater than 10/sup 4/ and time resolution is 10 ms. (3) The x-ray imaging system (XIS) measures the spatial structure of rapid fluctuations (0.1 to 100 kHZ) providing information on MHD phenomena, impurity transport rates, toroidal rotation velocity, plasma position, and the electron temperature profile. It uses an array of silicon surface-barrier diodes which view different chords of the plasma through a common slot aperture and operate in current (as opposed to counting) mode. The effectiveness of shields to protect detectors from fusion-neutron radiation effects has been studied both theoretically and experimentally.

  18. Energy dependence of normal branch quasi-periodic intensity oscillations in low-mass X-ray binaries

    NASA Technical Reports Server (NTRS)

    Miller, Guy S.; Lamb, Frederick K.

    1992-01-01

    The properties of the approximately 6 Hz quasi-periodic X-ray intensity oscillations observed in the low-mass X-ray binary Cyg X-2 when it is on the normal spectral branch are shown to be consistent with a model in which photons from a central source with a fixed spectrum are Comptonized by an oscillating radial inflow. As the electron scattering optical depth of the flow varies, the spectrum of the escaping X-rays appears to rotate about a pivot energy that depends mainly on the electron temperature in the flow. The temperature derived from the observed energy dependence of the Cyg X-2 normal branch oscillations is approximately 1 keV, in good agreement with the estimated Compton temperature of its X-ray spectrum. The mean optical depth tau of the Comptonizing flow is inferred to be about 10, while the change in tau over an oscillation is estimated to be about 1; both values are in good agreement with radiation hydrodcode simulations of the radial flow.

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

    SciTech Connect

    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.

    2014-09-15

    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.

  20. Approximated transport-of-intensity equation for coded-aperture x-ray phase-contrast imaging.

    PubMed

    Das, Mini; Liang, Zhihua

    2014-09-15

    Transport-of-intensity equations (TIEs) allow better understanding of image formation and assist in simplifying the "phase problem" associated with phase-sensitive x-ray measurements. In this Letter, we present for the first time to our knowledge a simplified form of TIE that models x-ray differential phase-contrast (DPC) imaging with coded-aperture (CA) geometry. The validity of our approximation is demonstrated through comparison with an exact TIE in numerical simulations. The relative contributions of absorption, phase, and differential phase to the acquired phase-sensitive intensity images are made readily apparent with the approximate TIE, which may prove useful for solving the inverse phase-retrieval problem associated with these CA geometry based DPC. PMID:26466281

  1. Systems and methods for detecting an image of an object by use of an X-ray beam having a polychromatic distribution

    DOEpatents

    Parham, Christopher; Zhong, Zhong; Pisano, Etta; Connor, Dean; Chapman, Leroy D.

    2010-06-22

    Systems and methods for detecting an image of an object using an X-ray beam having a polychromatic energy distribution are disclosed. According to one aspect, a method can include detecting an image of an object. The method can include generating a first X-ray beam having a polychromatic energy distribution. Further, the method can include positioning a single monochromator crystal in a predetermined position to directly intercept the first X-ray beam such that a second X-ray beam having a predetermined energy level is produced. Further, an object can be positioned in the path of the second X-ray beam for transmission of the second X-ray beam through the object and emission from the object as a transmitted X-ray beam. The transmitted X-ray beam can be directed at an angle of incidence upon a crystal analyzer. Further, an image of the object can be detected from a beam diffracted from the analyzer crystal.

  2. Comparing neutron and X-ray-based dual beam gauges for characterising industrial organic-based materials.

    PubMed

    Bartle, C Murray; Kroger, Chris; West, John G

    2005-01-01

    Comparisons are made of the neutron gamma transmission (NEUGAT) and dual energy X-ray absorption (DEXA) methods of measuring the composition of organic-based industrial products. A simple model is developed to allow comparisons to be made particularly of the measurement precision and the industrial performance. These gauges have similar applications but the latter gauge is shown to be more suitable for high and variable product throughputs. X-ray tube source and detector combinations provide higher beam fluxes, superior imaging and require less bulky shielding. PMID:15996469

  3. High-Resolution X-Ray and Light Beam Induced Current (LBIC) Measurements of Multcrystalline Silicon Solar Cells

    SciTech Connect

    Jellison Jr, Gerald Earle; Budai, John D; Bennett, Charlee J C; Tischler, Jonathan Zachary; Duty, Chad E; Yelundur, V.; Rohatgi, A.

    2010-01-01

    High-resolution, spatially-resolved x-ray Laue patterns and high-resolution light beam induced current (LBIC) measurements are combined to study two multicrystalline solar cells made from the Heat Exchanger Method (HEM) and the Sting Ribbon Growth technique. The LBIC measurements were made at 4 different wavelengths (488, 633, 780, and 980 nm), resulting in penetration depths ranging from <1 {mu}m to >100 {mu}m. There is a strong correlation between the x-ray and LBIC measurements, showing that some twins and grain boundaries are effective in the reduction of local quantum efficiency, while others are benign.

  4. Generating Ultrashort Coherent Soft X-ray Radiation in Storage Rings Using Angular-modulated Electron Beams

    SciTech Connect

    Xiang, D.; Wan, W.

    2010-08-23

    A technique is proposed to generate ultrashort coherent soft x-ray radiation in storage rings using angular-modulated electron beams. In the scheme a laser operating in the TEM01 mode is first used to modulate the angular distribution of the electron beam in an undulator. After passing through a special beam line with non-zero transfer matrix element R{sub 54}, the angular modulation is converted to density modulation which contains considerable higher harmonic contents of the laser. It is found that the harmonic number can be one or two orders of magnitude higher than the standard coherent harmonic generation method which relies on beam energy modulation. The technique has the potential of generating femtosecond coherent soft x-ray radiation directly from an infrared seed laser and may open new research opportunities for ultrafast sciences in storage rings.

  5. A simulation-based study on the influence of beam hardening in X-ray computed tomography for dimensional metrology.

    PubMed

    Lifton, Joseph J; Malcolm, Andrew A; McBride, John W

    2015-01-01

    X-ray computed tomography (CT) is a radiographic scanning technique for visualising cross-sectional images of an object non-destructively. From these cross-sectional images it is possible to evaluate internal dimensional features of a workpiece which may otherwise be inaccessible to tactile and optical instruments. Beam hardening is a physical process that degrades the quality of CT images and has previously been suggested to influence dimensional measurements. Using a validated simulation tool, the influence of spectrum pre-filtration and beam hardening correction are evaluated for internal and external dimensional measurements. Beam hardening is shown to influence internal and external dimensions in opposition, and to have a greater influence on outer dimensions compared to inner dimensions. The results suggest the combination of spectrum pre-filtration and a local gradient-based surface determination method are able to greatly reduce the influence of beam hardening in X-ray CT for dimensional metrology. PMID:25567408

  6. Chemical Environment Effects on K[beta]/K[alpha] Intensity Ratio: An X-Ray Fluorescence Experiment on Periodic Trends

    ERIC Educational Resources Information Center

    Durham, Chaney R.; Chase, Jeffery M.; Nivens, Delana A.; Baird, William H.; Padgett, Clifford W.

    2011-01-01

    X-ray fluorescence (XRF) data from an energy-dispersive XRF instrument were used to investigate the chlorine K[alpha] and K[beta] peaks in several group 1 salts. The ratio of the peak intensity is sensitive to the local chemical environment of the chlorine atoms studied in this experiment and it shows a periodic trend for these salts. (Contains 1…

  7. Operation of beam line facilities for real-time x-ray studies at Sector 7 of the advanced photon source. Final Report

    SciTech Connect

    Clarke, Roy

    2003-09-10

    This Final Report documents the research accomplishments achieved in the first phase of operations of a new Advanced Photon Source beam line (7-ID MHATT-CAT) dedicated to real-time x-ray studies. The period covered by this report covers the establishment of a world-class facility for time-dependent x-ray studies of materials. During this period many new and innovative research programs were initiated at Sector 7 with support of this grant, most notably using a combination of ultrafast lasers and pulsed synchrotron radiation. This work initiated a new frontier of materials research: namely, the study of the dynamics of materials under extreme conditions of high intensity impulsive laser irradiation.

  8. Data consistency-driven scatter kernel optimization for x-ray cone-beam CT.

    PubMed

    Kim, Changhwan; Park, Miran; Sung, Younghun; Lee, Jaehak; Choi, Jiyoung; Cho, Seungryong

    2015-08-01

    Accurate and efficient scatter correction is essential for acquisition of high-quality x-ray cone-beam CT (CBCT) images for various applications. This study was conducted to demonstrate the feasibility of using the data consistency condition (DCC) as a criterion for scatter kernel optimization in scatter deconvolution methods in CBCT. As in CBCT, data consistency in the mid-plane is primarily challenged by scatter, we utilized data consistency to confirm the degree of scatter correction and to steer the update in iterative kernel optimization. By means of the parallel-beam DCC via fan-parallel rebinning, we iteratively optimized the scatter kernel parameters, using a particle swarm optimization algorithm for its computational efficiency and excellent convergence. The proposed method was validated by a simulation study using the XCAT numerical phantom and also by experimental studies using the ACS head phantom and the pelvic part of the Rando phantom. The results showed that the proposed method can effectively improve the accuracy of deconvolution-based scatter correction. Quantitative assessments of image quality parameters such as contrast and structure similarity (SSIM) revealed that the optimally selected scatter kernel improves the contrast of scatter-free images by up to 99.5%, 94.4%, and 84.4%, and of the SSIM in an XCAT study, an ACS head phantom study, and a pelvis phantom study by up to 96.7%, 90.5%, and 87.8%, respectively. The proposed method can achieve accurate and efficient scatter correction from a single cone-beam scan without need of any auxiliary hardware or additional experimentation. PMID:26183058

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

    PubMed

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

    2016-02-01

    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 (∼10(19) W/cm(2)) 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

  10. Spectral energetic properties of the X-ray-boosted photoionization by an intense few-cycle laser

    NASA Astrophysics Data System (ADS)

    Ge, Yu-Cheng; He, Hai-Ping

    2014-07-01

    We report a discovery that an intense few-cycle laser pulse passing through gas leaves a fingerprint of its field envelope on the photoelectron energy spectrum, which involves continuous X-ray radiations. The spectrum resulting from the photoionization processes includes significant quantum enhancement and interference and exhibits interesting energetic properties. The spectral cut-off energies reflect the strength, time, and interference of the laser field modulation on the photoelectron energy. These energetic properties suggest a new method for precise intense-laser-pulse measurement in situ. The method has the advantages of accuracy, simplicity, speed, and large dynamic ranges (up to many orders of intensity).

  11. Routine chest x-rays in intensive care units: a systematic review and meta-analysis

    PubMed Central

    2012-01-01

    Introduction Chest x-rays (CXRs) are the most frequent radiological tests performed in the intensive care unit (ICU). However, the utility of performing daily routine CXRs is unclear. Methods We searched Medline and Embase (1948 to March 2011) for randomized and quasi-randomized controlled trials (RCTs) and before-after observational studies comparing a strategy of routine CXRs to a more restrictive approach with CXRs performed to investigate clinical changes among critically ill adults or children. In duplicate, we extracted data on the CXR strategy, study quality and clinical outcomes (ICU and hospital mortality; duration of mechanical ventilation and ICU and hospital stay). Results Nine studies (39,358 CXRs; 9,611 patients) were included in the meta-analysis. Three trials (N = 870) of moderate to good quality provided information on the safety of a restrictive routine CXR strategy; only one trial systematically assessed for missed findings. Pooled data from trials showed no evidence of effect of a restrictive approach on ICU mortality (risk ratio [RR] 1.04, 95% confidence interval [CI] 0.84 to 1.28, P = 0.72; two trials, N = 776), hospital mortality (RR 0.98, 95% CI 0.68 to 1.41, P = 0.91; two trials, N = 259), ICU length of stay (weighted mean difference [WMD] -0.86 days, 95% CI -2.38 to 0.66 days, P = 0.27; three trials, N = 870), hospital length of stay (WMD -2.50 days, 95% CI -6.62 to 1.61 days, P = 0.23; two trials, N = 259), or duration of mechanical ventilation (WMD -0.30 days, 95% CI -1.48 to 0.89 days, P = 0.62; three trials, N = 705). Adding data from six observational studies, one of which systematically screened for missed findings, gave similar results. Conclusions This meta-analysis did not detect any harm associated with a restrictive chest radiograph strategy. However, confidence intervals were wide and harm was not rigorously assessed. Therefore, the safety of abandoning routine CXRs in patients admitted to the ICU remains uncertain. PMID:22541022

  12. Measurement of high energy x-ray beam penumbra with Gafchromic trade mark sign EBT radiochromic film

    SciTech Connect

    Cheung Tsang; Butson, Martin J.; Yu, Peter K. N.

    2006-08-15

    High energy x-ray beam penumbra are measured using Gafchromic trade mark sign EBT film. Gafchromic trade mark sign EBT, due to its limited energy dependence and high spatial resolution provide a high level of accuracy for dose assessment in penumbral regions. The spatial resolution of film detector systems is normally limited by the scanning resolution of the densitometer. Penumbral widths (80%/20%) measured at D{sub max} were found to be 2.8, 3.0, 3.2, and 3.4 mm ({+-}0.2 mm) using 5, 10, 20, and 30 cm square field sizes, respectively, for a 6 MV linear accelerator produced x-ray beam. This is compared to 3.2 mm{+-}0.2 mm (Kodak EDR2) and 3.6 mm{+-}0.2 mm (Kodak X-Omat V) at 10 cmx10 cm measured using radiographic film. Using a zero volume extrapolation technique for ionization chamber measurements, the 10 cmx10 cm field penumbra at D{sub max} was measured to be 3.1 mm, a close match to Gafchromic trade mark sign EBT results. Penumbral measurements can also be made at other depths, including the surface, as the film does not suffer significantly from dosimetric variations caused by changing x-ray energy spectra. Gafchromic trade mark sign EBT film provides an adequate measure of penumbral dose for high energy x-ray beams.

  13. Interaction between x-ray and magnetic vortices

    NASA Astrophysics Data System (ADS)

    van Veenendaal, Michel

    2015-12-01

    The interaction between two topological objects, an x-ray beam carrying orbital angular momentum (OAM) and a magnetic vortex, is studied theoretically. The resonant x-ray scattering intensity is calculated as a function of the relative position of the magnetic and x-ray vortices. For a homogeneous system, the charge scattering is zero. For magnetic scattering, the intensity profile strongly depends on the relative topological indices of the x-ray and magnetic singularities. A strong enhancement in the intensity profile is observed for equal winding factors. Additionally, the profile displays edge effects, which depend on the scattering conditions, the radial dependence of the magnetic vortex, and the Laguerre-Gaussian mode of the OAM x-ray beam. The potential of resonant OAM x-ray scattering from magnetic vortices opens the door to study the dynamics and switching of magnetic vortices.

  14. Proton therapy versus intensity modulated x-ray therapy in the treatment of prostate cancer: Estimating secondary cancer risks

    NASA Astrophysics Data System (ADS)

    Fontenot, Jonas David

    External beam radiation therapy is used to treat nearly half of the more than 200,000 new cases of prostate cancer diagnosed in the United States each year. During a radiation therapy treatment, healthy tissues in the path of the therapeutic beam are exposed to high doses. In addition, the whole body is exposed to a low-dose bath of unwanted scatter radiation from the pelvis and leakage radiation from the treatment unit. As a result, survivors of radiation therapy for prostate cancer face an elevated risk of developing a radiogenic second cancer. Recently, proton therapy has been shown to reduce the dose delivered by the therapeutic beam to normal tissues during treatment compared to intensity modulated x-ray therapy (IMXT, the current standard of care). However, the magnitude of stray radiation doses from proton therapy, and their impact on this incidence of radiogenic second cancers, was not known. The risk of a radiogenic second cancer following proton therapy for prostate cancer relative to IMXT was determined for 3 patients of large, median, and small anatomical stature. Doses delivered to healthy tissues from the therapeutic beam were obtained from treatment planning system calculations. Stray doses from IMXT were taken from the literature, while stray doses from proton therapy were simulated using a Monte Carlo model of a passive scattering treatment unit and an anthropomorphic phantom. Baseline risk models were taken from the Biological Effects of Ionizing Radiation VII report. A sensitivity analysis was conducted to characterize the uncertainty of risk calculations to uncertainties in the risk model, the relative biological effectiveness (RBE) of neutrons for carcinogenesis, and inter-patient anatomical variations. The risk projections revealed that proton therapy carries a lower risk for radiogenic second cancer incidence following prostate irradiation compared to IMXT. The sensitivity analysis revealed that the results of the risk analysis depended only weakly on uncertainties in the risk model and inter-patient variations. Second cancer risks were sensitive to changes in the RBE of neutrons. However, the findings of the study were qualitatively consistent for all patient sizes and risk models considered, and for all neutron RBE values less than 100.

  15. Physiologically gated micro-beam radiation therapy using electronically controlled field emission x-ray source array

    NASA Astrophysics Data System (ADS)

    Chtcheprov, Pavel; Hadsell, Michael; Burk, Laurel; Ger, Rachel; Zhang, Lei; Yuan, Hong; Lee, Yueh Z.; Chang, Sha; Lu, Jianping; Zhou, Otto

    2013-03-01

    Micro-beam radiation therapy (MRT) uses parallel planes of high dose narrow (10-100 um in width) radiation beams separated by a fraction of a millimeter to treat cancerous tumors. This experimental therapy method based on synchrotron radiation has been shown to spare normal tissue at up to 1000Gy of entrance dose while still being effective in tumor eradication and extending the lifetime of tumor-bearing small animal models. Motion during the treatment can result in significant movement of micro beam positions resulting in broader beam width and lower peak to valley dose ratio (PVDR), and thus can reduce the effectiveness of the MRT. Recently we have developed the first bench-top image guided MRT system for small animal treatment using a high powered carbon nanotube (CNT) x-ray source array. The CNT field emission x-ray source can be electronically synchronized to an external triggering signal to enable physiologically gated firing of x-ray radiation to minimize motion blurring. Here we report the results of phantom study of respiratory gated MRT. A simulation of mouse breathing was performed using a servo motor. Preliminary results show that without gating the micro beam full width at tenth maximum (FWTM) can increase by 70% and PVDR can decrease up to 50%. But with proper gating, both the beam width and PVDR changes can be negligible. Future experiments will involve irradiation of mouse models and comparing histology stains between the controls and the gated irradiation.

  16. Energy calibration of energy-resolved photon-counting pixel detectors using laboratory polychromatic x-ray beams

    NASA Astrophysics Data System (ADS)

    Youn, Hanbean; Han, Jong Chul; Kam, Soohwa; Yun, Seungman; Kim, Ho Kyung

    2014-10-01

    Recently, photon-counting detectors capable of resolving incident x-ray photon energies have been considered for use in spectral x-ray imaging applications. For reliable use of energy-resolved photon-counting detectors (ERPCDs), energy calibration is an essential procedure prior to their use because variations in responses from each pixel of the ERPCD for incident photons, even at the same energy, are inevitable. Energy calibration can be performed using a variety of methods. In all of these methods, the photon spectra with well-defined peak energies are recorded. Every pixel should be calibrated on its own. In this study, we suggest the use of a conventional polychromatic x-ray source (that is typically used in laboratories) for energy calibration. The energy calibration procedure mainly includes the determination of the peak energies in the spectra, flood-field irradiation, determination of peak channels, and determination of calibration curves (i.e., the slopes and intercepts of linear polynomials). We applied a calibration algorithm to a CdTe ERPCD comprised of 128128 pixels with a pitch of 0.35 mm using highly attenuated polychromatic x-ray beams to reduce the pulse pile-up effect, and to obtain a narrow-shaped spectrum due to beam hardening. The averaged relative error in calibration curves obtained from 16,384 pixels was about 0.56% for 59.6 keV photons from an Americium radioisotope. This pixel-by-pixel energy calibration enhanced the signal- and contrast-to-noise ratios in images, respectively, by a factor of ~5 and 3 due to improvement in image homogeneity, compared to those obtained without energy calibration. One secondary finding of this study was that the x-ray photon spectra obtained using a common algorithm for computing x-ray spectra reasonably described the peaks in the measured spectra, which implies easier peak detection without the direct measurement of spectra using a separate spectrometer. The proposed method will be a useful alternative to conventional approaches using radioisotopes, a synchrotron, or specialized x-ray sources (e.g., characteristic or fluorescent x-rays) by reducing concerns over the beam flux, the irradiation field of view, accessibility, and cost.

  17. Peat archives from Siberia: Synchrotron beam scanning with X-ray fluorescence measurements

    NASA Astrophysics Data System (ADS)

    Phedorin, M. A.; Bobrov, V. A.; Zolotarev, K. V.

    2007-05-01

    We used a new approach to measure the downcore distribution of some major and trace elements that record the Holocene history of peat-forming processes in peat from the Elovka mesotrophic swamp (West Siberia). The approach implies continuous non-destructive scanning of natural wet-core fragments under a sharp synchrotron beam combined with measurements of the excited X-ray fluorescence, in attempt to avoid errors due to the loss of volatiles abundant in peat. The obtained data are in good agreement with the results of the certified methods of neutron activation gamma-spectrometry (INAA) and classical SR XRF, though, as we expected, there is some discrepancy in the contents of volatiles (Br, Zn) which are most probably lost in INAA and/or in ignition. The precision of the suggested SR XRF scanning resolved the variability of 18 elements in the peat-core deposited during 0-8 kyr bp at no worse than 30 years in most cases. The distribution of the measured elements provided a clue to the evolution of peat deposition environments that controlled biogenic production, aerosol input, post-depositional processes, and Ca mineralization associated with pore water circulation in soil during the non-mesotrophic stages of the swamp history.

  18. Local structure of human hair spatially resolved by sub-micron X-ray beam

    PubMed Central

    Stanić, Vesna; Bettini, Jefferson; Montoro, Fabiano Emmanuel; Stein, Aaron; Evans-Lutterodt, Kenneth

    2015-01-01

    Human hair has three main regions, the medulla, the cortex, and the cuticle. An existing model for the cortex suggests that the α-keratin- based intermediate filaments (IFs) align with the hair’s axis, but are orientationally disordered in-plane. We found that there is a new region in the cortex near the cuticle’s boundary in which the IFs are aligned with the hair’s axis, but additionally, they are orientationally ordered in-plane due to the presence of the cuticle/hair boundary. Further into the cortex, the IF arrangement becomes disordered, eventually losing all in-plane orientation. We also find that in the cuticle, a key diffraction feature is absent, indicating the presence of the β-keratin rather than that of the α-keratin phase. This is direct structural evidence that the cuticle contains β-keratin sheets. This work highlights the importance of using a sub-micron x-ray beam to unravel the structures of poorly ordered, multi-phase systems. PMID:26617337

  19. Local structure of human hair spatially resolved by sub-micron X-ray beam

    NASA Astrophysics Data System (ADS)

    Stanić, Vesna; Bettini, Jefferson; Montoro, Fabiano Emmanuel; Stein, Aaron; Evans-Lutterodt, Kenneth

    2015-11-01

    Human hair has three main regions, the medulla, the cortex, and the cuticle. An existing model for the cortex suggests that the α-keratin- based intermediate filaments (IFs) align with the hair’s axis, but are orientationally disordered in-plane. We found that there is a new region in the cortex near the cuticle’s boundary in which the IFs are aligned with the hair’s axis, but additionally, they are orientationally ordered in-plane due to the presence of the cuticle/hair boundary. Further into the cortex, the IF arrangement becomes disordered, eventually losing all in-plane orientation. We also find that in the cuticle, a key diffraction feature is absent, indicating the presence of the β-keratin rather than that of the α-keratin phase. This is direct structural evidence that the cuticle contains β-keratin sheets. This work highlights the importance of using a sub-micron x-ray beam to unravel the structures of poorly ordered, multi-phase systems.

  20. Output beam polarisation of x-ray lasers with transient inversion

    NASA Astrophysics Data System (ADS)

    Janulewicz, K. A.; Kim, C. M.; Stiel, H.; Kawachi, T.; Nishikino, M.; Hasegawa, N.

    2015-09-01

    We describe measurement results on the polarisation state of amplified spontaneous emission (ASE) signal from a collisionally pumped Ni-like Ag soft X-ray laser with a transient inversion. The result obtained with a calibrated membrane beam splitter as a polarisation state (P-state) selector shows that dominance one of the mutually perpendicular electric field components (p- or s-) in the output signal depends on the hydrodynamic state of the plasma medium. Hence, the output radiation has well defined polarisation state, even if this varies from shot to shot. Two different hydrodynamic state were referred as a "low gain" and "high gain" regimes and the allocated P-states had dominant s- and p-component, respectively. It was also shown that due to correlations between p- and s-components in the process of coherent amplification of noise, correct description of the polarisation state requires applying the generalised theory of polarisation and formulated there the generalised degree of polarisation (DOP). The critical role of active medium gain in the polarisation development is elucidated in a broader way.

  1. Specific features of two diffraction schemes for a widely divergent X-ray beam

    NASA Astrophysics Data System (ADS)

    Avetyan, K. T.; Levonyan, L. V.; Semerjian, H. S.; Arakelyan, M. M.; Badalyan, O. M.

    2015-03-01

    We investigated the specific features of two diffraction schemes for a widely divergent X-ray beam that use a circular diaphragm 30-50 ?m in diameter as a point source of characteristic radiation. In one of the schemes, the diaphragm was set in front of the crystal (the diaphragm-crystal ( d-c) scheme); in the other, it was installed behind the crystal (the crystal-diaphragm ( c-d) scheme). It was established that the diffraction image in the c-d scheme is a topographic map of the investigated crystal area. In the d-c scheme at L = 2 l ( l and L are the distances between the crystal and the diaphragm and between the photographic plate and the diaphragm, respectively), the branches of hyperbolas formed in this family of planes ( hkl) by the characteristic K ? and K ? radiations, including higher order reflections, converge into one straight line. It is experimentally demonstrated that this convergence is very sensitive to structural inhomogeneities in the crystal under study.

  2. A tetrahedron beam computed tomography benchtop system with a multiple pixel field emission x-ray tube

    SciTech Connect

    Xu, Xiaochao; Kim, Joshua; Laganis, Philip; Schulze, Derek; Liang, Yongguang; Zhang, Tiezhi

    2011-10-15

    Purpose: To demonstrate the feasibility of Tetrahedron Beam Computed Tomography (TBCT) using a carbon nanotube (CNT) multiple pixel field emission x-ray (MPFEX) tube. Methods: A multiple pixel x-ray source facilitates the creation of novel x-ray imaging modalities. In a previous publication, the authors proposed a Tetrahedron Beam Computed Tomography (TBCT) imaging system which comprises a linear source array and a linear detector array that are orthogonal to each other. TBCT is expected to reduce scatter compared with Cone Beam Computed Tomography (CBCT) and to have better detector performance. Therefore, it may produce improved image quality for image guided radiotherapy. In this study, a TBCT benchtop system has been developed with an MPFEX tube. The tube has 75 CNT cold cathodes, which generate 75 x-ray focal spots on an elongated anode, and has 4 mm pixel spacing. An in-house-developed, 5-row CT detector array using silicon photodiodes and CdWO{sub 4} scintillators was employed in the system. Hardware and software were developed for tube control and detector data acquisition. The raw data were preprocessed for beam hardening and detector response linearity and were reconstructed with an FDK-based image reconstruction algorithm. Results: The focal spots were measured at about 1 x 2 mm{sup 2} using a star phantom. Each cathode generates around 3 mA cathode current with 2190 V gate voltage. The benchtop system is able to perform TBCT scans with a prolonged scanning time. Images of a commercial CT phantom were successfully acquired. Conclusions: A prototype system was developed, and preliminary phantom images were successfully acquired. MPFEX is a promising x-ray source for TBCT. Further improvement of tube output is needed in order for it to be used in clinical TBCT systems.

  3. Upgrade of the 30-m x-ray pencil beam line at the Institute of Space and Astronautical Science

    NASA Astrophysics Data System (ADS)

    Hayashi, Takayuki; Sato, Toshiki; Kikuchi, Naomichi; Kurashima, Sho; Nakaniwa, Nozomi; Sato, Takuro; Iizuka, Ryo; Maeda, Yoshitomo; Ishida, Manabu

    2015-10-01

    The 30-m x-ray pencil beam line at the Institute of Space and Astronautical Science has been upgraded. The vacuum chamber has been replaced by a new cylindrical chamber of diameter 1.8μm and length 11.3μm. Stages on which a telescope and detectors had been mounted were also replaced. At the same time, a new charge-coupled device consisting of 1240×1152 pixels of size 22.5×22.5 μm2 was introduced. The detector stage can be moved along the x-ray beam in the vacuum chamber, which enables us to vary the distance between the sample and the detectors from 0.7 to 9μm. The two stages can be moved in a square region 500×500 mm2 in the plane normal to the x-ray beam. The pitching of moving axes of Y direction (horizontal and normal to the beam) of the sample and the detector stages is somewhat large, but does not exceed 60 arc sec. The pitching of the other axes and the yawing of all the axes are less than 30 arc sec. As for rolling, we could obtain only the upper limits because of the difficulty in measuring them. The upper limit of the Z direction (vertical and normal to the beam) of the detector stage moving axis is somewhat large and is about 60 arc sec, and those of the other axes are less than 30 arc sec. A summary of the beam line performance is presented. Soon after the upgrade, the ASTRO-H Soft X-ray telescopes were calibrated in this beam line.

  4. X-ray absorption, phase and dark-field tomography through a beam tracking approach.

    PubMed

    Vittoria, Fabio A; Endrizzi, Marco; Diemoz, Paul C; Zamir, Anna; Wagner, Ulrich H; Rau, Christoph; Robinson, Ian K; Olivo, Alessandro

    2015-01-01

    We present a development of the beam-tracking approach that allows its implementation in computed tomography. One absorbing mask placed before the sample and a high resolution detector are used to track variations in the beam intensity distribution caused by the sample. Absorption, refraction, and dark-field are retrieved through a multi-Gaussian interpolation of the beam. Standard filtered back projection is used to reconstruct three dimensional maps of the real and imaginary part of the refractive index, and of the dark-field signal. While the method is here demonstrated using synchrotron radiation, its low coherence requirements suggest a possible implementation with laboratory sources. PMID:26541117

  5. Transmissive x-ray beam position monitors with submicron position- and submillisecond time resolution

    SciTech Connect

    Fuchs, Martin R.; Holldack, Karsten; Erko, Alexei; Schaefers, Franz; Mueller, Uwe; Bullough, Mark; Walsh, Susanne; Wilburn, Colin

    2008-06-15

    We present the development of fast transmissive center-of-mass x-ray beam position monitors with a large active area, based on a thinned position sensitive detector in both a duo- and a tetra-lateral variant. The detectors were tested at BESSY beamlines BL14.1, KMC-1, and KMC-2 and yielded signal currents of up to 3 {mu}A/100 mA current at 10 keV photon energy using the monochromatic focused beam of BL14.1. The active area sizes were 1x1 and 3x3 mm{sup 2} for the duo-lateral and 5x5 mm{sup 2} for the tetra-lateral devices, with the duo-lateral detectors currently being available in sizes from 1x1 to 10x10 mm{sup 2} and thicknesses between 5 and 10 {mu}m. The presented detectors' thicknesses were measured to be 5 and 8 {mu}m with a corresponding transmission of up to 93% at 10 keV and 15% at 2.5 keV. Up to a detection bandwidth of 10 kHz, the monitors provide submicron position resolution. For lower detection bandwidths, the signal-to-noise reaches values of up to 6x10{sup 4} at 10 Hz, corresponding to a position resolution of better than 50 nm for both detector sizes. As it stands, this monitor design approach promises to be a generic solution for automation of state-of-the-art crystal monochromator beamlines.

  6. Time resolved, 2-D hard X-ray imaging of relativistic electron-beam target interactions on ETA-II

    SciTech Connect

    Crist, C.E.; Sampayan, S.; Westenskow, G.; Caporaso, G.; Houck, T.; Weir, J.; Trimble, D.; Krogh, M.

    1998-11-01

    Advanced radiographic applications require a constant source size less than 1 mm. To study the time history of a relativistic electron beam as it interacts with a bremsstrahlung converter, one of the diagnostics they use is a multi-frame time-resolved hard x-ray camera. They are performing experiments on the ETA-II accelerator at Lawrence Livermore National Laboratory to investigate details of the electron beam/converter interactions. The camera they are using contains 6 time-resolved images, each image is a 5 ns frame. By starting each successive frame 10 ns after the previous frame, they create a 6-frame movie from the hard x-rays produced from the interaction of the 50-ns electron beam pulse.

  7. Grazing-incidence X-ray diffraction of single GaAs nanowires at locations defined by focused ion beams

    PubMed Central

    Bussone, Genziana; Schott, Rdiger; Biermanns, Andreas; Davydok, Anton; Reuter, Dirk; Carbone, Gerardina; Schlli, Tobias U.; Wieck, Andreas D.; Pietsch, Ullrich

    2013-01-01

    Grazing-incidence X-ray diffraction measurements on single GaAs nanowires (NWs) grown on a (111)-oriented GaAs substrate by molecular beam epitaxy are reported. The positions of the NWs are intentionally determined by a direct implantation of Au with focused ion beams. This controlled arrangement in combination with a nanofocused X-ray beam allows the in-plane lattice parameter of single NWs to be probed, which is not possible for randomly grown NWs. Reciprocal space maps were collected at different heights along the NW to investigate the crystal structure. Simultaneously, substrate areas with different distances from the Au-implantation spots below the NWs were probed. Around the NWs, the data revealed a 0.4% decrease in the lattice spacing in the substrate compared with the expected unstrained value. This suggests the presence of a compressed region due to Au implantation. PMID:24046493

  8. On amplitude beam splitting of tender X-rays (2-8 keV photon energy) using conical diffraction from reflection gratings with laminar profile.

    PubMed

    Jark, Werner; Eichert, Diane

    2016-01-01

    Conical diffraction is obtained when a radiation beam impinges onto a periodically ruled surface structure parallel or almost parallel to the ruling. In this condition the incident intensity is diffracted through an arc, away from the plane of incidence. The diffracted intensity thus lies on a cone, which leads to the name `conical diffraction'. In this configuration almost no part of the ruled structure will produce any shadowing effect for the incident or the diffracted beam. Then, compared with a grating in the classical orientation, relatively higher diffraction efficiencies will be observed for fewer diffraction orders. When the incident beam is perfectly parallel to the grooves of a rectangular grating profile, the symmetry of the setup causes diffraction of the intensity symmetrically around the plane of incidence. This situation was previously tested experimentally in the VUV spectral range for the amplitude beam splitting of a radiation beam with a photon energy of 25 eV. In this case the ideally expected beam splitting efficiency of about 80% for the diffraction into the two first orders was confirmed for the optimum combination of groove depth and angle of grazing incidence. The feasibility of the amplitude beam splitting for hard X-rays with 12 keV photon energy by use of the same concept was theoretically confirmed. However, no related experimental data are presented yet, not even for lower energy soft X-rays. The present study reports the first experimental data for the conical diffraction from a rectangular grating profile in the tender X-ray range for photon energies of 4 keV and 6 keV. The expected symmetries are observed. The maximum absolute efficiency for beam splitting was measured to be only about 30%. As the reflectivity of the grating coating at the corresponding angle of grazing incidence was found to be only of the order of 50%, the relative beam splitting efficiency was thus 60%. This is to be compared also here with an ideally expected relative efficiency of 80%. It is predicted that a beam splitting efficiency exceeding 50% should be possible by use of more appropriate materials. PMID:26698049

  9. Wearable device for monitoring momentary presence of intense x-ray and/or ultra-violet radiations

    SciTech Connect

    Shriner, W.

    1981-03-10

    A credit-card-size clear-plastic-encased device can be worn or carried by a person to warn him of the momentary presence of dangerous intensities of ultra-violet and/or x-ray radiations. A base lamina (e.g. of cardboard) is coated with a material (e.g. zinc-cadmium sulfide or lead-barium sulfate) which fluoresces under such radiations. Numerals, letters, words or symbols are printed over the fluorescent coat with a material inhibitory to said radiations so that a warning message in dark print will appear on a light background when dangerous intensities of said radiations are present. An x-ray-warning area is covered with an ultra-violet absorbing screen so that said area will glow only under x-rays (Which rays will also activate the remaining ultra-violet-responsive area). The colors of the laminas and the coats are so selected that the messages are not visible when dangerous radiations are not present. If desired, only the message can be printed with fluorescent material so as to glow on a darker background. Optionally, step-layer attenuation devices can be added to indicate degrees of radiation; and reflecting surfaces can underlie the fluorescent coat to increase efficiency and/or sensitively.

  10. Hot Electron and X-ray Production from Intense Laser Irradiation of Wavelength-scale Polystyrene Spheres

    NASA Astrophysics Data System (ADS)

    Ditmire, T.; Sumeruk, H. A.; Kneip, S.; Symes, D. R.; Churina, I. V.; Belolipetski, A. V.; Dyer, G.; Bernstein, A.; Donnelly, T. D.

    2008-04-01

    In an attempt to control the electric fields at the surface of a high intensity solid target we have studied hot electron generation and x-ray production from targets coated with microspheres. This work is motivated by the possibility that spheres with size comparable to the wavelength of the incident laser radiation can result in electric field enhancements through well know Mie resonances. This local field enhancement can then lead to more efficient electron generation. We investigated hard x-ray (above 100 keV) generation from copper and fused silica targets coated with a monolayer covering of polystyrene microspheres. We performed the experiment using the 20 TW THOR laser system at the University of Texas. We frequency doubled the laser to improve temporal contrast and irradiated the spheres with 400 nm pulses at an intensity of 2 x 1017 W/cm2. Hard X-ray emission from the plasma was observed using filtered NaI scintillation detectors and K-alpha emission was measured with a Von Hamos spectrometer. We illuminated polystyrene spheres of diameters 0.1 -2.9 microns on a glass substrate, with the 400 nm 100fs pulse, and find that there is a clear Mie enhancement in the field and hot electron generation for a specific range of sphere sizes.

  11. Ground calibrations of the Solar Intensity X-ray Spectrometer (SIXS) on board BepiColombo

    NASA Astrophysics Data System (ADS)

    Lehtolainen, A.; Alha, L.; Huovelin, J.; Moissl, R.; Korpela, S.; Andersson, H.; Kuparinen, K.

    2014-01-01

    In this paper we present the methods, results, and analysis of the BepiColombo SIXS instruments' ground calibrations. The aim of these calibrations was to characterize the performance of the three SIXS X-ray detectors to enable reliable spectral analysis of the solar X-ray data. The ground calibrations for characterizing the performance of the three separate HPSi (High-Purity Silicon) PIN (Positive Intrinsic Negative) X-ray detectors included the following tasks. Determination of the energy resolution as a function of photon energy at different operational temperatures, determination of the detector sensitivity within the FoV (Field of View) as a function of the off-axis and roll angles, pile-up tests for determining the speed of the read out electronics, measurements of the low energy threshold of the energy scale, i.e. the minimum measurable photon energy corresponding to the adjustable software parameter, a comparison calibration of the fluorescence line fluxes with the SMART-1 XSM FS (Flight Spare) detector, and determination of the shifting of the energy scale as a function of the ambient temperature. We also describe the method and results of determining the geometrical area of the detector apertures based on the image analysis of very high resolution photographs obtained with by the Scanning Electron Microscope (SEM).

  12. In situ X-ray beam imaging using an off-axis magnifying coded aperture camera system.

    PubMed

    Kachatkou, Anton; Kyele, Nicholas; Scott, Peter; van Silfhout, Roelof

    2013-07-01

    An imaging model and an image reconstruction algorithm for a transparent X-ray beam imaging and position measuring instrument are presented. The instrument relies on a coded aperture camera to record magnified images of the footprint of the incident beam on a thin foil placed in the beam at an oblique angle. The imaging model represents the instrument as a linear system whose impulse response takes into account the image blur owing to the finite thickness of the foil, the shape and size of camera's aperture and detector's point-spread function. The image reconstruction algorithm first removes the image blur using the modelled impulse response function and then corrects for geometrical distortions caused by the foil tilt. The performance of the image reconstruction algorithm was tested in experiments at synchrotron radiation beamlines. The results show that the proposed imaging system produces images of the X-ray beam cross section with a quality comparable with images obtained using X-ray cameras that are exposed to the direct beam. PMID:23765302

  13. Thermal distortion of wavefront in high-intensity-laser system for inverse Compton x-ray generation

    NASA Astrophysics Data System (ADS)

    Ishikawa, Hiroki; Ito, Shinji; Endo, Akira; Yanagida, Tatsuya; Torizuka, Kenji; Sakai, Fumio; Washio, Masakazu

    2003-06-01

    We have developed a stable 7 terawatt (TW) (168 mJ per pulse, 24 fs pulse duration) Ti: sapphire laser system operating at 50 Hz for a generation of femtosecond X-ray pulses by inverse Compton scattering. We corrected the wavefront distortion of these high intensity laser pulses with adaptive optics using a Shack-Hartmann type wavefront sensor and a deformable mirror. We have also started developing a compact all-solid-state Yb: Sr5(PO4)3F (Yb: S-FAP) laser system to realize a practical X-ray pulse generation system. We measured thermal lensing induced in Yb: S-FAP crystal for design of a high-energy regenerative amplifier. In addition, we measured wavefront of the amplified pulses in the Yb: S-FAP regenerative amplifier with the wavefront sensor.

  14. Scanning x-ray microscope

    SciTech Connect

    Wang, C.

    1982-02-23

    A scanning x-ray microscope is described including: an x-ray source capable of emitting a beam of x-rays; a collimator positioned to receive the beam of x-rays and to collimate this beam, a focusing cone means to focus the beam of x-rays, directed by the collimator, onto a focal plane, a specimen mount for supporting a specimen in the focal plane to receive the focused beam of x-rays, and x-ray beam scanning means to relatively move the specimen and the focusing cone means and collimator to scan the focused x-ray beam across the specimen. A detector is disposed adjacent the specimen to detect flourescent photons emitted by the specimen upon exposure to the focused beam of x-rays to provide an electrical output representative of this detection. Means are included for displaying and/or recording the information provided by the output from the detector, as are means for providing information to the recording and/or display means representative of the scan rate and position of the focused x-ray beam relative to the specimen whereby the recording and/or display means can correlate the information received to record and/or display quantitive and distributive information as to the quantity and distribution of elements detected in the specimen. Preferably there is provided an x-ray beam modulation means upstream, relative to the direction of emission of the xray beam, of the focusing cone means.

  15. X-ray micro-beam characterization of lattice rotations and distortions due to an individual dislocation.

    PubMed

    Hofmann, Felix; Abbey, Brian; Liu, Wenjun; Xu, Ruqing; Usher, Brian F; Balaur, Eugeniu; Liu, Yuzi

    2013-01-01

    Understanding and controlling the behaviour of dislocations is crucial for a wide range of applications, from nano-electronics and solar cells to structural engineering alloys. Quantitative X-ray diffraction measurements of the strain fields due to individual dislocations, particularly in the bulk, however, have thus far remained elusive. Here we report the first characterization of a single dislocation in a freestanding GaAs/In0.2Ga0.8As/GaAs membrane by synchrotron X-ray micro-beam Laue diffraction. Our experimental X-ray data agrees closely with textbook anisotropic elasticity solutions for dislocations, providing one of few experimental validations of this fundamental theory. On the basis of the experimental uncertainty in our measurements, we predict the X-ray beam size required for three-dimensional measurements of lattice strains and rotations due to individual dislocations in the material bulk. These findings have important implications for the in situ study of dislocation structure formation, self-organization and evolution in the bulk. PMID:24216614

  16. Narrowband inverse Compton scattering x-ray sources at high laser intensities

    NASA Astrophysics Data System (ADS)

    Seipt, D.; Rykovanov, S. G.; Surzhykov, A.; Fritzsche, S.

    2015-03-01

    Narrowband x- and γ -ray sources based on the inverse Compton scattering of laser pulses suffer from a limitation of the allowed laser intensity due to the onset of nonlinear effects that increase their bandwidth. It has been suggested that laser pulses with a suitable frequency modulation could compensate this ponderomotive broadening and reduce the bandwidth of the spectral lines, which would allow one to operate narrowband Compton sources in the high-intensity regime. In this paper we therefore present the theory of nonlinear Compton scattering in a frequency-modulated intense laser pulse. We systematically derive the optimal frequency modulation of the laser pulse from the scattering matrix element of nonlinear Compton scattering, taking into account the electron spin and recoil. We show that, for some particular scattering angle, an optimized frequency modulation completely cancels the ponderomotive broadening for all harmonics of the backscattered light. We also explore how sensitively this compensation depends on the electron-beam energy spread and emittance, as well as the laser focusing.

  17. Characterization of low-energy photon-emitting brachytherapy sources and kilovoltage x-ray beams using spectrometry

    NASA Astrophysics Data System (ADS)

    Moga, Jacqueline D.

    Low-energy photon sources are used in therapeutic radiation oncology for brachytherapy with low dose-rate (LDR) sources and for superficial and orthovoltage therapy with kilovolt-age x-ray beams. Current dosimetry methods for these sources utilize energy-integrating devices, such as thermoluminescent dosimeters and ionization chambers. This thesis work investigates the dosimetry of LDR brachytherapy sources and kilovoltage x-ray beams using spectrometry, which preserves the energy-specific source output. Several LDR brachytherapy source models were measured with a reverse-electrode germanium (REGe) detector. The measured spectra were corrected for MCNP5-calculated detector response using a deconvolution algorithm (Beach, 2005). The peak areas determined from the corrected spectra were used to calculate the dose-rate constant (Chen and Nath, 2001) and the air-kerma strength. Dose-rate constant results agreed well with the published values (Rivard et al., 2004; Chen and Nath, 2007). Air-kerma strength results were systematically 2%--5% low compared to calibration values and primary air-kerma strength measurements. The spectrometry methods for LDR brachytherapy sources offer a promising alternative to existing experimental techniques, but further work is necessary to improve agreement with the current air-kerma strength standard methodology. Spectra of 20kVp---250kVp x-ray beams were measured with a low-energy germanium detector (LEGe). The LEGe spectrometry system was modeled in MCNP5 to calculate a detector response function. Backward stripping, which showed less variability than deconvolution, was used for correcting the measured x-ray spectra. The corrected experimental spectra were compared to spectra from: (1) Monte Carlo simulations of the full x-ray tube with EGSnrc, (2) the SpekCalc program (Poludniowski et al., 2009), and (3) the Gesellschaft fur Strahlen-und Umweltforschung mbH Munchen (GSF) Report 560. Agreement was best for the UW60-M through UW150-M beams and poorest for the UW20-M and UW-30M beams due to incomplete modeling of tungsten L-shell fluorescence peaks by the EGSnrc code and SpekCalc program. Monte Carlo simulations of thermoluminescent dosimeter and ionization chamber dosimetry demonstrated that variability in response due to the input spectrum was within the limits of accurate geometry simulation. This work has contributed to more accurate x-ray spectra that can be used for future dosimetry investigations with these beams.

  18. X-Ray Exam: Wrist

    MedlinePLUS

    ... person's wrist. During the examination, an X-ray machine sends a beam of radiation through the wrist, ... have a table and a large X-ray machine hanging from the ceiling. Parents are usually able ...

  19. X-Ray Exam: Foot

    MedlinePLUS

    ... person's foot. During the examination, an X-ray machine sends a beam of radiation through the foot, ... contain a table and a large X-ray machine hanging from the ceiling. Parents are usually able ...

  20. Concurrence of monoenergetic electron beams and bright X-rays from an evolving laser-plasma bubble.

    PubMed

    Yan, Wenchao; Chen, Liming; Li, Dazhang; Zhang, Lu; Hafz, Nasr A M; Dunn, James; Ma, Yong; Huang, Kai; Su, Luning; Chen, Min; Sheng, Zhengming; Zhang, Jie

    2014-04-22

    Desktop laser plasma acceleration has proven to be able to generate gigaelectronvolt-level quasi-monoenergetic electron beams. Moreover, such electron beams can oscillate transversely (wiggling motion) in the laser-produced plasma bubble/channel and emit collimated ultrashort X-ray flashes known as betatron radiation with photon energy ranging from kiloelectronvolts to megaelectronvolts. This implies that usually one cannot obtain bright betatron X-rays and high-quality electron beams with low emittance and small energy spread simultaneously in the same accelerating wave bucket. Here, we report the first (to our knowledge) experimental observation of two distinct electron bunches in a single laser shot, one featured with quasi-monoenergetic spectrum and another with continuous spectrum along with large emittance. The latter is able to generate high-flux betatron X-rays. Such is observed only when the laser self-guiding is extended over 4 mm at a fixed plasma density (4 10(18) cm(-3)). Numerical simulation reveals that two bunches of electrons are injected at different stages due to the bubble evolution. The first bunch is injected at the beginning to form a stable quasi-monoenergetic electron beam, whereas the second one is injected later due to the oscillation of the bubble size as a result of the change of the laser spot size during the propagation. Due to the inherent temporal synchronization, this unique electron-photon source can be ideal for pump-probe applications with femtosecond time resolution. PMID:24711405

  1. Development of an on-axis-visualization stage to observe and align sample with an x-ray beam

    NASA Astrophysics Data System (ADS)

    Gutirrez-Len, A.; Heyman, C.; Rubio-Zuazo, J.; Castro, G. R.

    2013-03-01

    An on-axis-visualization stage for accurate sample alignment respect to X-ray beam has been designed and implemented at the diffraction and absorption/fluorescence stations of the BM25-SpLine synchrotron beamline at the ESRF. It is mostly intended for studies involving heterogeneous samples where the analysis is restricted to a particular area of the sample. The OAV system provides a parallax-free image of the sample. This is accomplished by a front-surface mirror at an angle of 45 degrees to reflect the visible sample image 90 up to a zoom optics and digital colour CCD camera. A pinhole (PH) on the mirror in combination with a second PH 100 mm backward provides an on-axis collimated X-ray beam at image centre. The collimator is aligned to the beam axis by two angular and two translational high-precision motorized motions. The OAV stage is synchronized with the sample positioning stage, by a computer software so that the desired sample region is aligned on the X-ray beam by selecting it on the image produced by the video camera. In this work, a complete description of the on-axis-visualization system will be presented including the experimental determination of the alignment accuracy.

  2. Concurrence of monoenergetic electron beams and bright X-rays from an evolving laser-plasma bubble

    PubMed Central

    Yan, Wenchao; Chen, Liming; Li, Dazhang; Zhang, Lu; Hafz, Nasr A. M.; Dunn, James; Ma, Yong; Huang, Kai; Su, Luning; Chen, Min; Sheng, Zhengming; Zhang, Jie

    2014-01-01

    Desktop laser plasma acceleration has proven to be able to generate gigaelectronvolt-level quasi-monoenergetic electron beams. Moreover, such electron beams can oscillate transversely (wiggling motion) in the laser-produced plasma bubble/channel and emit collimated ultrashort X-ray flashes known as betatron radiation with photon energy ranging from kiloelectronvolts to megaelectronvolts. This implies that usually one cannot obtain bright betatron X-rays and high-quality electron beams with low emittance and small energy spread simultaneously in the same accelerating wave bucket. Here, we report the first (to our knowledge) experimental observation of two distinct electron bunches in a single laser shot, one featured with quasi-monoenergetic spectrum and another with continuous spectrum along with large emittance. The latter is able to generate high-flux betatron X-rays. Such is observed only when the laser self-guiding is extended over 4 mm at a fixed plasma density (4 × 1018 cm−3). Numerical simulation reveals that two bunches of electrons are injected at different stages due to the bubble evolution. The first bunch is injected at the beginning to form a stable quasi-monoenergetic electron beam, whereas the second one is injected later due to the oscillation of the bubble size as a result of the change of the laser spot size during the propagation. Due to the inherent temporal synchronization, this unique electron–photon source can be ideal for pump–probe applications with femtosecond time resolution. PMID:24711405

  3. A beam branching method for timing and spectral characterization of hard X-ray free-electron lasers

    PubMed Central

    Katayama, Tetsuo; Owada, Shigeki; Togashi, Tadashi; Ogawa, Kanade; Karvinen, Petri; Vartiainen, Ismo; Eronen, Anni; David, Christian; Sato, Takahiro; Nakajima, Kyo; Joti, Yasumasa; Yumoto, Hirokatsu; Ohashi, Haruhiko; Yabashi, Makina

    2016-01-01

    We report a method for achieving advanced photon diagnostics of x-ray free-electron lasers (XFELs) under a quasi-noninvasive condition by using a beam-splitting scheme. Here, we used a transmission grating to generate multiple branches of x-ray beams. One of the two primary diffracted branches (+1st-order) is utilized for spectral measurement in a dispersive scheme, while the other (−1st-order) is dedicated for arrival timing diagnostics between the XFEL and the optical laser pulses. The transmitted x-ray beam (0th-order) is guided to an experimental station. To confirm the validity of this timing-monitoring scheme, we measured the correlation between the arrival timings of the −1st and 0th branches. The observed error was as small as 7.0 fs in root-mean-square. Our result showed the applicability of the beam branching scheme to advanced photon diagnostics, which will further enhance experimental capabilities of XFEL. PMID:26958586

  4. Quality indexes based on water measurements for low and medium energy x-ray beams: A theoretical study with PENELOPE

    SciTech Connect

    Chica, U.; Anguiano, M.; Lallena, A. M.; Vilches, M.

    2014-01-15

    Purpose : To study the use of quality indexes based on ratios of absorbed doses in water at two different depths to characterize x-ray beams of low and medium energies. Methods : A total of 55 x-ray beam spectra were generated with the codes XCOMP5R and SPEKCALC and used as input of a series of Monte Carlo simulations performed with PENELOPE, in which the percentage depth doses in water and thek{sub Q,Q{sub 0}} factors, defined in the TRS-398 protocol, were determined for each beam. Some of these calculations were performed by simulating the ionization chamber PTW 30010. Results : The authors found that the relation betweenk{sub Q,Q{sub 0}} and the ratios of absorbed doses at two depths is almost linear. A set of ratios statistically compatible with that showing the best fit has been determined. Conclusions : The results of this study point out which of these ratios of absorbed doses in water could be used to better characterize x-ray beams of low and medium energies.

  5. A beam branching method for timing and spectral characterization of hard X-ray free-electron lasers.

    PubMed

    Katayama, Tetsuo; Owada, Shigeki; Togashi, Tadashi; Ogawa, Kanade; Karvinen, Petri; Vartiainen, Ismo; Eronen, Anni; David, Christian; Sato, Takahiro; Nakajima, Kyo; Joti, Yasumasa; Yumoto, Hirokatsu; Ohashi, Haruhiko; Yabashi, Makina

    2016-05-01

    We report a method for achieving advanced photon diagnostics of x-ray free-electron lasers (XFELs) under a quasi-noninvasive condition by using a beam-splitting scheme. Here, we used a transmission grating to generate multiple branches of x-ray beams. One of the two primary diffracted branches (+1st-order) is utilized for spectral measurement in a dispersive scheme, while the other (-1st-order) is dedicated for arrival timing diagnostics between the XFEL and the optical laser pulses. The transmitted x-ray beam (0th-order) is guided to an experimental station. To confirm the validity of this timing-monitoring scheme, we measured the correlation between the arrival timings of the -1st and 0th branches. The observed error was as small as 7.0 fs in root-mean-square. Our result showed the applicability of the beam branching scheme to advanced photon diagnostics, which will further enhance experimental capabilities of XFEL. PMID:26958586

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

    SciTech Connect

    Chakravarty, U.; Rao, B. S.; Arora, V.; Upadhyay, A.; Singhal, H.; Naik, P. A.; Chakera, J. A.; Mukherjee, C.; Gupta, P. D.

    2013-07-29

    Enhanced water window x-ray emission (2344 ) 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.

  7. X-ray beamsplitter

    DOEpatents

    Ceglio, Natale M. (Livermore, CA); Stearns, Daniel S. (Mountain View, CA); Hawryluk, Andrew M. (Modesto, CA); Barbee, Jr., Troy W. (Palo Alto, CA)

    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.

  8. 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.

  9. MOSFET dosimetry with high spatial resolution in intense synchrotron-generated x-ray microbeams.

    PubMed

    Siegbahn, E A; Bruer-Krisch, E; Bravin, A; Nettelbeck, H; Lerch, M L F; Rosenfeld, A B

    2009-04-01

    Various dosimeters have been tested for assessing absorbed doses with microscopic spatial resolution in targets irradiated by high-flux, synchrotron-generated, low-energy (approximately 30-300 keV) x-ray microbeams. A MOSFET detector has been used for this study since its radio sensitive element, which is extraordinarily narrow (approximately 1 microm), suits the main applications of interest, microbeam radiation biology and microbeam radiation therapy (MRT). In MRT, micrometer-wide, centimeter-high, and vertically oriented swaths of tissue are irradiated by arrays of rectangular x-ray microbeams produced by a multislit collimator (MSC). We used MOSFETs to measure the dose distribution, produced by arrays of x-ray microbeams shaped by two different MSCs, in a tissue-equivalent phantom. Doses were measured near the center of the arrays and maximum/minimum (peak/valley) dose ratios (PVDRs) were calculated to determine how variations in heights and in widths of the microbeams influenced this for the therapy, potentially important parameter. Monte Carlo (MC) simulations of the absorbed dose distribution in the phantom were also performed. The results show that when the heights of the irradiated swaths were below those applicable to clinical therapy (< 1 mm) the MC simulations produce estimates of PVDRs that are up to a factor of 3 higher than the measured values. For arrays of higher microbeams (i.e., 25 microm x 1 cm instead of 25 x 500 microm2), this difference between measured and simulated PVDRs becomes less than 50%. Closer agreement was observed between the measured and simulated PVDRs for the Tecomet MSC (current collimator design) than for the Archer MSC. Sources of discrepancies between measured and simulated doses are discussed, of which the energy dependent response of the MOSFET was shown to be among the most important. PMID:19472618

  10. 3D Algebraic Iterative Reconstruction for Cone-Beam X-Ray Differential Phase-Contrast Computed Tomography

    PubMed Central

    Fu, Jian; Hu, Xinhua; Velroyen, Astrid; Bech, Martin; Jiang, Ming; Pfeiffer, Franz

    2015-01-01

    Due to the potential of compact imaging systems with magnified spatial resolution and contrast, cone-beam x-ray differential phase-contrast computed tomography (DPC-CT) has attracted significant interest. The current proposed FDK reconstruction algorithm with the Hilbert imaginary filter will induce severe cone-beam artifacts when the cone-beam angle becomes large. In this paper, we propose an algebraic iterative reconstruction (AIR) method for cone-beam DPC-CT and report its experiment results. This approach considers the reconstruction process as the optimization of a discrete representation of the object function to satisfy a system of equations that describes the cone-beam DPC-CT imaging modality. Unlike the conventional iterative algorithms for absorption-based CT, it involves the derivative operation to the forward projections of the reconstructed intermediate image to take into account the differential nature of the DPC projections. This method is based on the algebraic reconstruction technique, reconstructs the image ray by ray, and is expected to provide better derivative estimates in iterations. This work comprises a numerical study of the algorithm and its experimental verification using a dataset measured with a three-grating interferometer and a mini-focus x-ray tube source. It is shown that the proposed method can reduce the cone-beam artifacts and performs better than FDK under large cone-beam angles. This algorithm is of interest for future cone-beam DPC-CT applications. PMID:25775480

  11. Monte Carlo comparison of x-ray and proton CT for range calculations of proton therapy beams

    NASA Astrophysics Data System (ADS)

    Arbor, N.; Dauvergne, D.; Dedes, G.; Létang, J. M.; Parodi, K.; Quiñones, C. T.; Testa, E.; Rit, S.

    2015-10-01

    Proton computed tomography (CT) has been described as a solution for imaging the proton stopping power of patient tissues, therefore reducing the uncertainty of the conversion of x-ray CT images to relative stopping power (RSP) maps and its associated margins. This study aimed to investigate this assertion under the assumption of ideal detection systems. We have developed a Monte Carlo framework to assess proton CT performances for the main steps of a proton therapy treatment planning, i.e. proton or x-ray CT imaging, conversion to RSP maps based on the calibration of a tissue phantom, and proton dose simulations. Irradiations of a computational phantom with pencil beams were simulated on various anatomical sites and the proton range was assessed on the reference, the proton CT-based and the x-ray CT-based material maps. Errors on the tissue’s RSP reconstructed from proton CT were found to be significantly smaller and less dependent on the tissue distribution. The imaging dose was also found to be much more uniform and conformal to the primary beam. The mean absolute deviation for range calculations based on x-ray CT varies from 0.18 to 2.01 mm depending on the localization, while it is smaller than 0.1 mm for proton CT. Under the assumption of a perfect detection system, proton range predictions based on proton CT are therefore both more accurate and more uniform than those based on x-ray CT.

  12. Ultra-bright, ultra-broadband hard x-ray driven by laser-produced energetic electron beams

    SciTech Connect

    Shi, Yin; Shen, Baifei; Zhang, Xiaomei; Wang, Wenpeng; Ji, Liangliang; Zhang, Lingang; Xu, Jiancai; Yu, Yahong; Zhao, Xueyan; Wang, Xiaofeng; Yi, Longqing; Xu, Tongjun; Xu, Zhizhan

    2013-09-15

    We propose a new method of obtaining a compact ultra-bright, ultra-broadband hard X-ray source. This X-ray source has a high peak brightness in the order of 10{sup 22} photons/(s mm{sup 2} mrad{sup 2} 0.1\\%BW), an ultrashort duration (10 fs), and a broadband spectrum (flat distribution from 0.1 MeV to 4 MeV), and thus has wide-ranging potential applications, such as in ultrafast Laue diffraction experiments. In our scheme, laser-plasma accelerators (LPAs) provide driven electron beams. A foil target is placed oblique to the beam direction so that the target normal sheath field (TNSF) is used to provide a bending force. Using this TNSF-kick scheme, we can fully utilize the advantages of current LPAs, including their high charge, high energy, and low emittance.

  13. High aspect ratio x-ray waveguide channels fabricated by e-beam lithography and wafer bonding

    SciTech Connect

    Neubauer, H.; Hoffmann, S.; Kanbach, M.; Haber, J.; Kalbfleisch, S.; Krüger, S. P.; Salditt, T.

    2014-06-07

    We report on the fabrication and characterization of hard x-ray waveguide channels manufactured by e-beam lithography, reactive ion etching and wafer bonding. The guiding layer consists of air or vacuum and the cladding material of silicon, which is favorable in view of minimizing absorption losses. The specifications for waveguide channels which have to be met in the hard x-ray range to achieve a suitable beam confinement in two orthogonal directions are extremely demanding. First, high aspect ratios up to 10{sup 6} have to be achieved between lateral structure size and length of the guides. Second, the channels have to be deeply embedded in material to warrant the guiding of the desired modes while absorbing all other (radiative) modes in the cladding material. We give a detailed report on device fabrication with the respective protocols and parameter optimization, the inspection and the optical characterization.

  14. Scanning x-ray microdiffraction with submicron white beam for strain and orientation mapping in thin films

    SciTech Connect

    Tamura, N.; MacDowell, A.A.; Spolenak, R.; Valek, B.C.; Bravman, J.C.; Brown, W.L.; Celestre, R.S.; Padmore, H.A.; Batterman, B.W.; Patel, J.R.

    2003-01-14

    Scanning X-ray Microdiffraction (m-SXRD) combines the use of high brilliance synchrotron sources with the latest achromatic X-ray focusing optics and fast large area 2D-detector technology. Using white beams or a combination of white and monochromatic beams, it allows for orientation and strain/stress mapping of polycrystalline thin films with submicron spatial resolution. The technique is described in detail as applied to the study of thin aluminium and copper blanket films and lines following electromigration testing and/or thermal cycling experiments. It is shown that there are significant orientation and strain/stress variations between grains and inside individual grains. A polycrystalline film when investigated at the granular (micron) level shows a highly mechanically inhomogeneous medium that allows insight into its mesoscopic properties. If the m-SXRD data are averaged over a macroscopic range, results show good agreement with direct macroscopic texture and stress measurements .

  15. X-ray luminescence computed tomography imaging based on X-ray distribution model and adaptively split Bregman method.

    PubMed

    Chen, Dongmei; Zhu, Shouping; Cao, Xu; Zhao, Fengjun; Liang, Jimin

    2015-07-01

    X-ray luminescence computed tomography (XLCT) has become a promising imaging technology for biological application based on phosphor nanoparticles. There are mainly three kinds of XLCT imaging systems: pencil beam XLCT, narrow beam XLCT and cone beam XLCT. Narrow beam XLCT can be regarded as a balance between the pencil beam mode and the cone-beam mode in terms of imaging efficiency and image quality. The collimated X-ray beams are assumed to be parallel ones in the traditional narrow beam XLCT. However, we observe that the cone beam X-rays are collimated into X-ray beams with fan-shaped broadening instead of parallel ones in our prototype narrow beam XLCT. Hence we incorporate the distribution of the X-ray beams in the physical model and collected the optical data from only two perpendicular directions to further speed up the scanning time. Meanwhile we propose a depth related adaptive regularized split Bregman (DARSB) method in reconstruction. The simulation experiments show that the proposed physical model and method can achieve better results in the location error, dice coefficient, mean square error and the intensity error than the traditional split Bregman method and validate the feasibility of method. The phantom experiment can obtain the location error less than 1.1 mm and validate that the incorporation of fan-shaped X-ray beams in our model can achieve better results than the parallel X-rays. PMID:26203388

  16. X-ray luminescence computed tomography imaging based on X-ray distribution model and adaptively split Bregman method

    PubMed Central

    Chen, Dongmei; Zhu, Shouping; Cao, Xu; Zhao, Fengjun; Liang, Jimin

    2015-01-01

    X-ray luminescence computed tomography (XLCT) has become a promising imaging technology for biological application based on phosphor nanoparticles. There are mainly three kinds of XLCT imaging systems: pencil beam XLCT, narrow beam XLCT and cone beam XLCT. Narrow beam XLCT can be regarded as a balance between the pencil beam mode and the cone-beam mode in terms of imaging efficiency and image quality. The collimated X-ray beams are assumed to be parallel ones in the traditional narrow beam XLCT. However, we observe that the cone beam X-rays are collimated into X-ray beams with fan-shaped broadening instead of parallel ones in our prototype narrow beam XLCT. Hence we incorporate the distribution of the X-ray beams in the physical model and collected the optical data from only two perpendicular directions to further speed up the scanning time. Meanwhile we propose a depth related adaptive regularized split Bregman (DARSB) method in reconstruction. The simulation experiments show that the proposed physical model and method can achieve better results in the location error, dice coefficient, mean square error and the intensity error than the traditional split Bregman method and validate the feasibility of method. The phantom experiment can obtain the location error less than 1.1 mm and validate that the incorporation of fan-shaped X-ray beams in our model can achieve better results than the parallel X-rays. PMID:26203388

  17. Research and development of an electron beam focusing system for a high-brightness X-ray generator

    PubMed Central

    Sakai, Takeshi; Ohsawa, Satoshi; Sakabe, Noriyoshi; Sugimura, Takashi; Ikeda, Mitsuo

    2011-01-01

    A new type of rotating anticathode X-ray generator, where an electron beam of up to 60?keV irradiates the inner surface of a U-shaped Cu anticathode, has achieved a beam brilliance of 130?kW mm?2 (at 2.3?kW). A higher-flux electron beam is expected from simulation by optimizing the geometry of a combined-function-type magnet instead of the fringing field of the bending magnet. In order to minimize the size of the X-ray source the electron beam has been focused over a short distance by a new combined-function bending magnet, whose geometrical shape was determined by simulation using the Opera-3D, General Particle Tracer and CST-STUDIO codes. The result of the simulation clearly shows that the role of combined functions in both the bending and the steering magnets is important for focusing the beam to a small size. FWHM sizes of the beam are predicted by simulation to be 0.45?mm (horizontal) and 0.05?mm (vertical) for a 120?keV/75?mA beam, of which the effective brilliance is about 500?kW mm?2 on the supposition of a two-dimensional Gaussian distribution. High-power tests have begun using a high-voltage 120?kV/75?mA power supply for the X-ray generator instead of 60?kV/100?mA. The beam focus size on the target will be verified in the experiments. PMID:21169692

  18. Research and development of an electron beam focusing system for a high-brightness X-ray generator.

    PubMed

    Sakai, Takeshi; Ohsawa, Satoshi; Sakabe, Noriyoshi; Sugimura, Takashi; Ikeda, Mitsuo

    2011-01-01

    A new type of rotating anticathode X-ray generator, where an electron beam of up to 60 keV irradiates the inner surface of a U-shaped Cu anticathode, has achieved a beam brilliance of 130 kW mm(-2) (at 2.3 kW). A higher-flux electron beam is expected from simulation by optimizing the geometry of a combined-function-type magnet instead of the fringing field of the bending magnet. In order to minimize the size of the X-ray source the electron beam has been focused over a short distance by a new combined-function bending magnet, whose geometrical shape was determined by simulation using the Opera-3D, General Particle Tracer and CST-STUDIO codes. The result of the simulation clearly shows that the role of combined functions in both the bending and the steering magnets is important for focusing the beam to a small size. FWHM sizes of the beam are predicted by simulation to be 0.45 mm (horizontal) and 0.05 mm (vertical) for a 120 keV/75 mA beam, of which the effective brilliance is about 500 kW mm(-2) on the supposition of a two-dimensional Gaussian distribution. High-power tests have begun using a high-voltage 120 kV/75 mA power supply for the X-ray generator instead of 60 kV/100 mA. The beam focus size on the target will be verified in the experiments. PMID:21169692

  19. Optimisation of NSLS-II Blade X-ray Beam Position Monitors: from Photoemission type to Diamond Detector

    SciTech Connect

    ILINSKI P.

    2012-07-10

    Optimisation of blade type x-ray beam position monitors (XBPM) was performed for NSLS-II undulator IVU20. Blade material, con and #64257;guration and operation principle was analysed in order to improve XBPM performance. Optimisation is based on calculation of the XBPM signal spatial distribution. Along with standard photoemission type XBPM a Diamond Detector Blades (DDB) were analysed as blades for XBPMs. DDB XBPMs can help to overcome drawbacks of the photoemission blade XBPMs.

  20. X-ray diffraction analysis of an osmium silicide epilayer grown on Si(1 0 0) by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Amir, F. Z.; Cottier, R. J.; Golding, T. D.; Donner, W.; Anibou, N.; Stokes, D. W.

    2006-09-01

    Osmium silicide epilayers have been grown by molecular beam epitaxy on (1 0 0)-oriented Si wafers. Multiple-phase (Os 2Si 3 and OsSi 2) and single-phase epilayers are observed, depending on the growth parameters. In this paper we report on a detailed investigation of the structure of a single-phase Os 2Si 3 epilayer and epilayer/silicon interface using X-ray diffraction, and reflectivity analysis. Optical absorption results will also be presented.