Specimen Holder for Analytical Electron Microscopes

NASA Technical Reports Server (NTRS)

Clanton, U. S.; Isaacs, A. M.; Mackinnon, I.

1985-01-01

Reduces spectral contamination by spurious X-ray. Specimen holder made of compressed carbon, securely retains standard electron microscope grid (disk) 3 mm in diameter and absorbs backscattered electrons that otherwise generate spurious X-rays. Since holder inexpensive, dedicated to single specimen when numerous samples examined.

X-ray Reciprocal Space Mapping of Graded Al x Ga1 - x N Films and Nanowires.

PubMed

Stanchu, Hryhorii V; Kuchuk, Andrian V; Kladko, Vasyl P; Ware, Morgan E; Mazur, Yuriy I; Zytkiewicz, Zbigniew R; Belyaev, Alexander E; Salamo, Gregory J

2016-12-01

The depth distribution of strain and composition in graded Al x Ga1 - x N films and nanowires (NWs) are studied theoretically using the kinematical theory of X-ray diffraction. By calculating [Formula: see text] reciprocal space maps (RSMs), we demonstrate significant differences in the intensity distributions from graded Al x Ga1 - x N films and NWs. We attribute these differences to relaxation of the substrate-induced strain on the NWs free side walls. Finally, we demonstrate that the developed X-ray reciprocal space map model allows for reliable depth profiles of strain and Al composition determination in both Al x Ga1 - x N films and NWs.

Thin film growth studies using time-resolved x-ray scattering

NASA Astrophysics Data System (ADS)

Kowarik, Stefan

2017-02-01

Thin-film growth is important for novel functional materials and new generations of devices. The non-equilibrium growth physics involved is very challenging, because the energy landscape for atomic scale processes is determined by many parameters, such as the diffusion and Ehrlich-Schwoebel barriers. We review the in situ real-time techniques of x-ray diffraction (XRD), x-ray growth oscillations and diffuse x-ray scattering (GISAXS) for the determination of structure and morphology on length scales from Å to µm. We give examples of time resolved growth experiments mainly from molecular thin film growth, but also highlight growth of inorganic materials using molecular beam epitaxy (MBE) and electrochemical deposition from liquids. We discuss how scaling parameters of rate equation models and fundamental energy barriers in kinetic Monte Carlo methods can be determined from fits of the real-time x-ray data.

Thin film growth studies using time-resolved x-ray scattering.

PubMed

Kowarik, Stefan

2017-02-01

Thin-film growth is important for novel functional materials and new generations of devices. The non-equilibrium growth physics involved is very challenging, because the energy landscape for atomic scale processes is determined by many parameters, such as the diffusion and Ehrlich-Schwoebel barriers. We review the in situ real-time techniques of x-ray diffraction (XRD), x-ray growth oscillations and diffuse x-ray scattering (GISAXS) for the determination of structure and morphology on length scales from Å to µm. We give examples of time resolved growth experiments mainly from molecular thin film growth, but also highlight growth of inorganic materials using molecular beam epitaxy (MBE) and electrochemical deposition from liquids. We discuss how scaling parameters of rate equation models and fundamental energy barriers in kinetic Monte Carlo methods can be determined from fits of the real-time x-ray data.

Measurements of reciprocity law failure in green-sensitive X-ray films.

PubMed

Arnold, B A; Eisenberg, H; Bjärngard, B E

1978-02-01

Reciprocity law failure was measured for four brands of medical x-ray films exposed with intensifying screens. Three of the films are green light-sensitized for use in combination with green light-emitting rare-earth screens. These films showed larger reciprocity failure effects than one conventional blue-sensitive film, Dupont Cronex-2. Development conditions had a small effect on reciprocity failure. As part of the investigation, a detector was constructed with a response that accurately monitors the light emission from the double screen-cassette combination over a wide range of x-ray photon energies.

Preventing bacterial growth on implanted device with an interfacial metallic film and penetrating X-rays.

PubMed

An, Jincui; Sun, An; Qiao, Yong; Zhang, Peipei; Su, Ming

2015-02-01

Device-related infections have been a big problem for a long time. This paper describes a new method to inhibit bacterial growth on implanted device with tissue-penetrating X-ray radiation, where a thin metallic film deposited on the device is used as a radio-sensitizing film for bacterial inhibition. At a given dose of X-ray, the bacterial viability decreases as the thickness of metal film (bismuth) increases. The bacterial viability decreases with X-ray dose increases. At X-ray dose of 2.5 Gy, 98% of bacteria on 10 nm thick bismuth film are killed; while it is only 25% of bacteria are killed on the bare petri dish. The same dose of X-ray kills 8% fibroblast cells that are within a short distance from bismuth film (4 mm). These results suggest that penetrating X-rays can kill bacteria on bismuth thin film deposited on surface of implant device efficiently.

[Quality assurance from the viewpoint of the x-ray film industry].

PubMed

von Volkmann, T

1992-08-01

The parameters of a film-screen-combination are listed in the directive to section 16 of the german X-ray Regulation. These parameters are determined by methods described in DIN standards and published by the manufacturer. Comparable but less precise parameters are determined in the Acceptance Test. For physical reasons it is not possible to determine the speed of an X-ray film or the intensification factor of a screen separately. The films, screens and processing chemicals delivered by the members of the manufacturer association ZVEI are kept below a deviation (expressed as relative contribution to the system speed S) of +/- 10% for the majority of products, the upper limit is +/- 15%. Poor storage and transport conditions may adversely affect the quality of X-ray films. A special labeling of the film box shall serve to guarantee safe distribution channels. The processing conditions are adjusted at the Acceptance Test according to the manufacturers recommendations. The Constancy Test of film processing serves to maintain these correct conditions. Methods deviating from the DIN-method are of limited (Bayerische method) or no value (Stuttgart method).

Characterization of aluminum nitride based films with high resolution X-ray fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Anagnostopoulos, D. F.; Siozios, A.; Patsalas, P.

2018-02-01

X-ray fluorescence spectra of Al based films are measured, using a lab-scale wavelength dispersive flat crystal spectrometer. Various structures of AlN films were studied, like single layered, capped, stratified, nanostructured, crystalline, or amorphous. By optimizing the set-up for enhanced energy resolution and detection efficiency, the measured line shapes of Κα, Kβ, and KLL radiative Auger transitions are shown to be adequately detailed to allow chemical characterization. The chemistry identification is based on the pattern comparison of the emitted line shape from the chemically unknown film and the reference line shapes from standard materials, recorded under identical experimental conditions. The ultimate strength of lab-scale high resolution X-ray fluorescence spectroscopy on film analysis is verified, in cases that ordinary applied techniques like X-ray photoelectron and X-ray diffraction fail, while the characterization refers to the non-destructive determination of the bulk properties of the film and not to its surface, as the probed depth is in the micrometer range.

High-Performance X-ray Detection in a New Analytical Electron Microscope

NASA Technical Reports Server (NTRS)

Lyman, C. E.; Goldstein, J. I.; Williams, D. B.; Ackland, D. W.; vonHarrach, S.; Nicholls, A. W.; Statham, P. J.

1994-01-01

X-ray detection by energy-dispersive spectrometry in the analytical electron microscope (AEM) is often limited by low collected X-ray intensity (P), modest peak-to-background (P/B) ratios, and limitations on total counting time (tau) due to specimen drift and contamination. A new AFM has been designed with maximization of P. P/B, and tau as the primary considerations. Maximization of P has been accomplished by employing a field-emission electron gun, X-ray detectors with high collection angles, high-speed beam blanking to allow only one photon into the detector at a time, and simultaneous collection from two detectors. P/B has been maximized by reducing extraneous background signals generated at the specimen holder, the polepieces and the detector collimator. The maximum practical tau has been increased by reducing specimen contamination and employing electronic drift correction. Performance improvments have been measured using the NIST standard Cr thin film. The 0-3 steradian solid angle of X-ray collection is the highest value available. The beam blanking scheme for X-ray detection provides 3-4 times greater throughput of X-rays at high count rates into a recorded spectrum than normal systems employing pulse-pileup rejection circuits. Simultaneous X-ray collection from two detectors allows the highest X-ray intensity yet recorded to be collected from the NIST Cr thin film. The measured P/B of 6300 is the highest level recorded for an AEM. In addition to collected X-ray intensity (cps/nA) and P/B measured on the standard Cr film, the product of these can be used as a figure-of-merit to evaluate instruments. Estimated minimum mass fraction (MMF) for Cr measured on the standard NIST Cr thin film is also proposed as a figure-of-merit for comparing X-ray detection in AEMs. Determinations here of the MMF of Cr detectable show at least a threefold improvement over previous instruments.

Development of x-ray laminography under an x-ray microscopic condition

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

Hoshino, Masato; Uesugi, Kentaro; Takeuchi, Akihisa

2011-07-15

An x-ray laminography system under an x-ray microscopic condition was developed to obtain a three-dimensional structure of laterally-extended planar objects which were difficult to observe by x-ray tomography. An x-ray laminography technique was introduced to an x-ray transmission microscope with zone plate optics. Three prototype sample holders were evaluated for x-ray imaging laminography. Layered copper grid sheets were imaged as a laminated sample. Diatomite powder on a silicon nitride membrane was measured to confirm the applicability of this method to non-planar micro-specimens placed on the membrane. The three-dimensional information of diatom shells on the membrane was obtained at a spatialmore » resolution of sub-micron. Images of biological cells on the membrane were also obtained by using a Zernike phase contrast technique.« less

Thoracic spine x-ray

MedlinePlus

Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... The test is done in a hospital radiology department or in the health care provider's office. You will lie on the x-ray table in different positions. If the x-ray ...

X-ray beamsplitter

DOEpatents

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

1989-01-01

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

An Atomic-Scale X-ray View of Functional Oxide Films

NASA Astrophysics Data System (ADS)

Tung, I.-Cheng

Complex oxides are a class of materials that exhibit a wide variety of physical functionalities, such as ferroelectricity, colossal magnetoresistance, mulitferroicity and superconductivity, with outstanding potential for meeting many of our technological demands. The primary objective of this dissertation is to understand the structural and electronic behavior of complex oxide ultrathin films subjected to confinement, lattice misfit and broken symmetry at the interface. In complex oxide ultrathin films, heteroepitaxial synthesis has evolved into a reliable strategy to engineer orbital-lattice interactions in correlated materials and led to new and entirely unexpected phenomena at their interfaces. I experimentally demonstrated that the bulk crystal symmetry directs the atomic and orbital responses adopted by coherently strained ultrathin films of RNiO3 (R = La, Nd) with detailed X-ray scattering, polarization-dependent X-ray absorption spectroscopy (XAS) and supported by a mathematical point group symmetry analysis, found that strain-stabilized phases maintain a ``memory'' of their bulk state. This topic, however, touched only upon the properties of such films. A fundamental challenge in this research area occurs before this and centers around the understanding of how to create high-quality films with arbitrary configurations. A longstanding challenge in the oxide thin film community has been the growth of An+1BnO3 n+1 Ruddlesden-Popper (RP) compounds. To understand this problem, we have utilized a newly constructed oxide MBE with in situ synchrotron X-ray scattering capability to study the initial growth of such layered oxides and track the dynamic evolution. X-ray results are supported by theoretical calculations that demonstrated the layered oxide films dynamically rearrange during growth, leading to structures that are highly unexpected, and suggest a general approach that may be essential for the construction of metastable RP phases with performing the first

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.

X-Ray Diffraction Apparatus

NASA Technical Reports Server (NTRS)

Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

1996-01-01

An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

Thermalization of X-rays in evaporated tin and bismuth films used as the absorbing materials in X-ray calorimeters

NASA Astrophysics Data System (ADS)

Stahle, C. K.; Kelley, R. L.; Moseley, S. H.; Szymkowiak, A. E.; Juda, M.; McCammon, D.; Zhang, J.

1993-11-01

We have investigated the use of evaporated tin and bismuth films as the absorbing materials in X-ray calorimeters. When the films were deposited directly on monolithic silicon calorimeters, the output signal from both Sn and Bi devices was strongly dependent on the location of the absorption event relative to the ion-implanted thermistors, presumably indicating thermistor sensitivity to a non-thermal spectrum of phonons. With Sn films we also observed that a component of the thermalization proceeded slowly, relative to a complete thermalization reference. The thermalization function could be modified by trapping magnetic flux within the film. In order to distinguish thermalization effects in the films from the thermistor sensitivity to energetic phonons, we deposited Sn and Bi films on thin Si substrates which we then affixed to calorimeters using epoxy. With glued Sn films, we were able to attain as good as 13.6 eV resolution of 6 keV X-rays with no excess broadening of the line beyond the width of the baseline, while similarly made Bi devices showed excess broadening.

Resonant soft x-ray GISAXS on block copolymer films

NASA Astrophysics Data System (ADS)

Wang, Cheng; Araki, T.; Watts, B.; Ade, H.; Hexemer, A.; Park, S.; Russell, T. P.; Schlotter, W. F.; Stein, G. E.; Tang, C.; Kramer, E. J.

2008-03-01

Ordered block copolymer thin films may have important applications in modern device fabrication. Current characterization methods such as conventional GISAXS have fixed electron density contrast that can be overwhelmed by surface scattering. However, soft x-rays have longer wavelength, energy dependent contrast and tunable penetration, making resonant GISAXS a very promising tool for probing nanostructured polymer thin films. Our preliminary investigation was performed using PS-b-P2VP block copolymer films on beam-line 5-2 SSRL, and beam-line 6.3.2 at ALS, LBNL. The contrast/sensitivity of the scattering pattern varies significantly with photon energy close to the C K-edge (˜290 eV). Also, higher order peaks are readily observed, indicating hexagonal packing structure in the sample. Comparing to the hard x-ray GISAXS data of the same system, it is clear that resonant GISAXS has richer data and better resolution. Beyond the results on the A-B diblock copolymers, results on ABC block copolymers are especially interesting.

Thin-film X-ray filters on microstructured substrates and their thermophysical properties

NASA Astrophysics Data System (ADS)

Mitrofanov, A. V.

2018-02-01

It is shown that structured substrates having micron- or submicron-sized through holes and coated with an ultrathin organic film can be used for the fabrication of thin-film X-ray filters via direct growth of functional layers on a substrate by sputter deposition, without additional complex processing steps. An optimised process is considered for the fabrication of X-ray filters on support structures in the form of electroplated fine nickel grids and on track-etched polymer membranes with micron- and submicrondiameter through pores. 'Optimisation' is here taken to mean matching the sputter deposition conditions with the properties of substrates so as to avoid overheating. The filters in question are intended for both imaging and single-channel detectors operating in the soft X-ray and vacuum UV spectral regions, at wavelengths from 10 to 60 nm. Thermal calculations are presented for the heating of ultrathin layers of organic films and thin-film support substrates during the sputter deposition of aluminium or other functional materials. The paper discusses approaches for cooling thinfilm composites during the sputter deposition process and the service of the filters in experiments and gives a brief overview of the works that utilised filters produced by the described technique on microstructured substrates, including orbital solar X-ray research in the framework of the CORONAS programme and laboratory laser plasma experiments.

Comparison of light and x-ray sensitometric responses of double-emulsion films for different processing conditions.

PubMed

Blendl, C; Buhr, E

2001-12-01

The effects of different film processing conditions on light and x-ray sensitometric responses were compared for a variety of double-emulsion x-ray films. The processing conditions were altered by changes of the developer temperature. Three different exposure variants were applied: x-ray sensitometry using two stepped neutral density attenuators between film and screens, simultaneous double-sided light sensitometry, and single-sided light sensitometry. 13 different types of double-emulsion x-ray films were investigated, among them three asymmetric films. In the special case of exposing the asymmetric films with the single-sided light sensitometer, a method was investigated where each side of the film is exposed at different locations and the sum effect is analyzed. From each sensitometric curve shape two parameters, the logarithmic speed (logS) and the average gradient (G), were evaluated. The results of this study can be summarized as follows: (1) Single-sided and double-sided light sensitometers revealed almost equal changes of logS when the processing conditions are altered. Thus, single-sided light sensitometers can serve as a substitute for double-sided light sensitometers provided that suited exposure methods are used and appropriate sensitometric parameters are evaluated. (2) Light sensitometry quantitatively indicated changes of the film processing that affect the x-ray speed. Hence, light sensitometry is a useful method to monitor changes in film processing.

Micro X-ray diffraction analysis of thin films using grazing-exit conditions.

PubMed

Noma, T; Iida, A

1998-05-01

An X-ray diffraction technique using a hard X-ray microbeam for thin-film analysis has been developed. To optimize the spatial resolution and the surface sensitivity, the X-ray microbeam strikes the sample surface at a large glancing angle while the diffracted X-ray signal is detected with a small (grazing) exit angle. Kirkpatrick-Baez optics developed at the Photon Factory were used, in combination with a multilayer monochromator, for focusing X-rays. The focused beam size was about 10 x 10 micro m. X-ray diffraction patterns of Pd, Pt and their layered structure were measured. Using a small exit angle, the signal-to-background ratio was improved due to a shallow escape depth. Under the grazing-exit condition, the refraction effect of diffracted X-rays was observed, indicating the possibility of surface sensitivity.

{ital In-situ} x-ray investigation of hydrogen charging in thin film bimetallic electrodes

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

Jisrawi, N.M.; Wiesmann, H.; Ruckman, M.W.

Hydrogen uptake and discharge by thin metallic films under potentiostatic control was studied using x-ray diffraction at the National Synchrotron Light Source (NSLS). The formation of metal-hydrogen phases in Pd, Pd-capped Nb and Pd/Nb multilayer electrode structures was deduced from x-ray diffraction data and correlated with the cyclic voltammetry (CV) peaks. The x-ray data was also used to construct a plot of the hydrogen concentration as a function of cell potential for a multilayered thin film. {copyright} {ital 1997 Materials Research Society.}

Influence of annealing on X-ray radiation sensing properties of TiO2 thin film

NASA Astrophysics Data System (ADS)

Sarma, M. P.; Kalita, J. M.; Wary, G.

2018-03-01

A recent study shows that the titanium dioxide (TiO2) thin film synthesised by a chemical bath deposition technique is a very useful material for the X-ray radiation sensor. In this work, we reported the influence of annealing on the X-ray radiation detection sensitivity of the TiO2 film. The films were annealed at 333 K, 363 K, 393 K, 473 K, and 573 K for 1 hour. Structural analyses showed that the microstrain and dislocation density decreased whereas the average crystallite size increased with annealing. The band gap of the films also decreased from 3.26 eV to 3.10 eV after annealing. The I-V characteristics record under the dark condition and under the X-ray irradiation showed that the conductivity increased with annealing. The influence of annealing on the detection sensitivity was negligible if the bias voltage applied across the films was low (within 0.2 V‒1.0 V). At higher bias voltage (>1.0 V), the contribution of electrons excited by X-ray became less significant which affected the detection sensitivity.

A comparison of Kodak Ultraspeed and Ektaspeed plus dental X-ray films for the detection of dental caries.

PubMed

Wong, A; Monsour, P A; Moule, A J; Basford, K E

2002-03-01

Using the fastest dental X-ray film available is an easy way of reducing exposure to ionizing radiation. However, the diagnostic ability of fast films for the detection of proximal surface caries must be demonstrated before these films will become universally accepted. Extracted premolar and molar teeth were arranged to simulate a bitewing examination and radiographed using Ultraspeed and Ektaspeed Plus dental X-ray films. Three different exposure times were used for each film type. Six general dentists were used to determine the presence and depth of the decay in the proximal surfaces of the teeth radiographed. The actual extent of the decay in the teeth was determined by sectioning the teeth and examining them under a microscope. There was no significant difference between the two films for the mean correct diagnosis. However, there was a significant difference between the means for the three exposure times used for Ultraspeed film. The practitioners used were not consistent in their ability to make a correct diagnosis, or for the film for which they got the highest correct diagnosis. Ektaspeed Plus dental X-ray film is just as reliable as Ultraspeed dental X-ray film for the detection of proximal surface decay. The effect of underexposure was significant for Ultraspeed, but not for Ektaspeed Plus. Patient exposure can be reduced significantly with no loss of diagnostic ability by changing from Ultraspeed X-ray film to Ektaspeed Plus X-ray film.

Characterization of SiGe thin films using a laboratory X-ray instrument.

PubMed

Ulyanenkova, Tatjana; Myronov, Maksym; Benediktovitch, Andrei; Mikhalychev, Alexander; Halpin, John; Ulyanenkov, Alex

2013-08-01

The technique of reciprocal space mapping using X-rays is a recognized tool for the nondestructive characterization of epitaxial films. X-ray scattering from epitaxial Si 0.4 Ge 0.6 films on Si(100) substrates using a laboratory X-ray source was investigated. It is shown that a laboratory source with a rotating anode makes it possible to investigate the material parameters of the super-thin 2-6 nm layers. For another set of partially relaxed layers, 50-200 nm thick, it is shown that from a high-resolution reciprocal space map, conditioned from diffuse scattering on dislocations, it is possible to determine quantitatively from the shape of a diffraction peak (possessing no thickness fringes) additional parameters such as misfit dislocation density and layer thickness as well as concentration and relaxation.

Sizes of X-ray radiation coherent domains in thin SmS films and their visualization

NASA Astrophysics Data System (ADS)

Sharenkova, N. V.; Kaminskii, V. V.; Petrov, S. N.

2011-09-01

The size of X-ray radiation coherent domains (250 ± 20 Å) is determined in a thin polycrystalline SmS film using X-ray diffraction patterns (θ-2θ scanning, DRON-2 diffractometer, Cu K α radiation) and the Selyakov-Scherrer formula with allowance for the effect of microstrains. An image of this film is taken with a transmission electron microscope, and regions with a characteristic size of 240 Å are clearly visible in it. It is concluded that X-ray radiation coherent domains are visualized.

Characterization of SiGe thin films using a laboratory X-ray instrument

PubMed Central

Ulyanenkova, Tatjana; Myronov, Maksym; Benediktovitch, Andrei; Mikhalychev, Alexander; Halpin, John; Ulyanenkov, Alex

2013-01-01

The technique of reciprocal space mapping using X-rays is a recognized tool for the nondestructive characterization of epitaxial films. X-ray scattering from epitaxial Si0.4Ge0.6 films on Si(100) substrates using a laboratory X-ray source was investigated. It is shown that a laboratory source with a rotating anode makes it possible to investigate the material parameters of the super-thin 2–6 nm layers. For another set of partially relaxed layers, 50–200 nm thick, it is shown that from a high-resolution reciprocal space map, conditioned from diffuse scattering on dislocations, it is possible to determine quantitatively from the shape of a diffraction peak (possessing no thickness fringes) additional parameters such as misfit dislocation density and layer thickness as well as concentration and relaxation. PMID:24046495

Radiation damage in polymer films from grazing-incidence X-ray scattering measurements

DOE PAGES

Vaselabadi, Saeed Ahmadi; Shakarisaz, David; Ruchhoeft, Paul; ...

2016-02-16

Grazing-incidence X-ray scattering (GIXS) is widely used to analyze the crystallinity and nanoscale structure in thin polymer films. However, ionizing radiation will generate free radicals that initiate cross-linking and/or chain scission, and structural damage will impact the ordering kinetics, thermodynamics, and crystallinity in many polymers. We report a simple methodology to screen for beam damage that is based on lithographic principles: films are exposed to patterns of x-ray radiation, and changes in polymer structure are revealed by immersing the film in a solvent that dissolves the shortest chains. The experiments are implemented with high throughput using the standard beam linemore » instrumentation and a typical GIXS configuration. The extent of damage (at a fixed radiation dose) depends on a range of intrinsic material properties and experimental variables, including the polymer chemistry and molecular weight, exposure environment, film thickness, and angle of incidence. The solubility switch for common polymers is detected within 10-60 sec at ambient temperature, and we verified that this first indication of damage corresponds with the onset of network formation in glassy polystyrene and a loss of crystallinity in polyalkylthiophenes. Therefore, grazing-incidence x-ray patterning offers an efficient approach to determine the appropriate data acquisition times for any GIXS experiment.« less

Quantitative determination of radio-opacity: equivalence of digital and film X-ray systems.

PubMed

Nomoto, R; Mishima, A; Kobayashi, K; McCabe, J F; Darvell, B W; Watts, D C; Momoi, Y; Hirano, S

2008-01-01

To evaluate the equivalence of a digital X-ray system (DenOptix) to conventional X-ray film in terms of the measured radio-opacity of known filled-resin materials and the suitability of attenuation coefficient for radio-opacity determination. Discs of five thicknesses (0.5-2.5mm) and step-wedges of each of three composite materials of nominal aluminum-equivalence of 50%, 200% and 450% were used. X-ray images of a set of discs (or step-wedge), an aluminum step-wedge, and a lead block were taken at 65 kV and 10 mA at a focus-film distance of 400 mm for 0.15s and 1.6s using an X-ray film or imaging plate. Radio-opacity was determined as equivalent aluminum thickness and attenuation coefficient. The logarithm of the individual optical density or gray scale value, corrected for background, was plotted against thickness, and the attenuation coefficient determined from the slope. The method of ISO 4049 was used for equivalent aluminum thickness. The equivalent aluminum thickness method is not suitable for materials of low radio-opacity, while the attenuation coefficient method could be used for all without difficulty. The digital system gave attenuation coefficients of greater precision than did film, but the use of automatic gain control (AGC) distorted the outcome unusably. Attenuation coefficient is a more precise and generally applicable approach to the determination of radio-opacity. The digital system was equivalent to film but with less noise. The use of AGC is inappropriate for such determinations.

Early predictive value of supine and upright X-ray films of odontoid fractures treated with halo-vest immobilization.

PubMed

Kim, David H; Vaccaro, Alexander R; Affonso, Jesse; Jenis, Louis; Hilibrand, Alan S; Albert, Todd J

2008-01-01

Although halo-vest immobilization remains a common form of treatment for type II odontoid fractures, nonunion and C1-2 instability may be the result in up to 20% to 40% of patients. Supine and upright lateral X-ray films may allow early identification of patients likely to fail halo-vest treatment and earlier surgical treatment with decreased morbidity from prolonged unsuccessful halo-vest immobilization. A prospective cohort study was performed. Twenty patients with type II odontoid fractures. Posttreatment nonunion and C1-2 instability as determined by plain X-ray films and computed tomography scan. Both supine and upright lateral X-ray films were obtained immediately after halo-vest application and at the 2-week, 6-week, and 3-month follow-up. Flexion-extension lateral X-ray films were obtained after halo-vest removal. Patients with nonunion or instability underwent computed tomography scan. Upright X-ray films were compared serially to identify loss of reduction. Pairs of supine and upright X-ray films were compared to measure any change in displacement or angulation upon transition from supine to upright position. Nonunion patients were compared with healed patients to determine any difference in fracture behavior based on serial supine and upright X-ray films. Twenty patients with type II odontoid fractures were identified during the study period. Three patients with multiple trauma underwent immediate surgical stabilization. Three elderly patients with nondisplaced fractures were treated in a cervical orthosis. Fourteen patients initiated and completed 3 months of halo-vest immobilization. After halo-vest removal, 4 of 14 patients (29%) showed radiographic nonunion or instability. In all 4 nonunion patients, supine and upright radiographs at 2 weeks revealed change in fracture angulation > or =5 degrees between the supine and upright positions. In three of these patients standard serial upright lateral X-ray films failed to identify any loss of reduction. In

Irreversible metal-insulator transition in thin film VO2 induced by soft X-ray irradiation

NASA Astrophysics Data System (ADS)

Singh, V. R.; Jovic, V.; Valmianski, I.; Ramirez, J. G.; Lamoureux, B.; Schuller, Ivan K.; Smith, K. E.

2017-12-01

In this study, we show the ability of soft x-ray irradiation to induce room temperature metal-insulator transitions (MITs) in VO2 thin films grown on R-plane sapphire. The ability of soft x-rays to induce MIT in VO2 thin films is confirmed by photoemission spectroscopy and soft x-ray spectroscopy measurements. When irradiation was discontinued, the systems do not return to the insulating phase. Analysis of valence band photoemission spectra revealed that the density of states (DOSs) of the V 3d band increased with irradiation time, while the DOS of the O 2p band decreased. We use these results to propose a model in which the MIT is driven by oxygen desorption from thin films during irradiation.

Probing molecular orientations in thin films by x-ray photoelectron spectroscopy

NASA Astrophysics Data System (ADS)

Li, Y.; Li, P.; Lu, Z.-H.

2018-03-01

A great number of functional organic molecules in active thin-film layers of optoelectronic devices have highly asymmetric structures, such as plate-like, rod-like, etc. This makes molecular orientation an important aspect in thin-films as it can significantly affect both the optical and electrical performance of optoelectronic devices. With a combination of in-situ ultra violet photoelectron spectroscopy (UPS) and x-ray photoelectron spectroscopy (XPS) investigations for organic molecules having a broad range of structural properties, we discovered a rigid connection of core levels and frontier highest occupied molecular orbital levels at organic interfaces. This finding opens up opportunities of using X-ray photoemission spectroscopy as an alternative tool to UPS for providing an easy and unambiguous data interpretation in probing molecular orientations.

Implant image quality in dental radiographs recorded using a customized imaging guide or a standard film holder.

PubMed

Schropp, Lars; Stavropoulos, Andreas; Spin-Neto, Rubens; Wenzel, Ann

2012-01-01

To compare a customized imaging guide and a standard film holder for obtaining optimally projected intraoral radiographs of dental implants. Intraoral radiographs of four screw-type implants with different inclination placed in an upper or lower dental phantom model were recorded by 32 groups of examiners after a short instruction in the use of the RB-RB/LB-LB mnemonic rule. Half of the examiners recorded the images using a standard film holder and the other half used a customized imaging guide. Each radiograph was assessed under blinded conditions with regard to rendering of the implant threads and was assigned to one of four quality categories: (1) perfect, (2) not perfect, but clinically acceptable, (3) not acceptable, and (4) hopeless. For the upper jaw, the same number of exposures per implant were made to achieve an acceptable image (P=0.86) by the standard film holder method (median=2) and the imaging guide method (median=2). For the lower jaw, medians for the imaging guide method and the film holder method were 1 and 2, respectively (P=0.004). For the imaging guide method, the first exposure was rated as perfect/acceptable in 62% of the cases and for the film holder method in 41% of the cases (P=0.013). After ≤ 2 exposures, 78% (imaging guide method) and 69% (film holder method) of the implant images were perfect/acceptable (P=0.23). The implant inclination did not have a major influence on the outcomes. Perfect or acceptable images were achieved after two exposures with the same frequency either using a customized imaging guide method or a standard film holder method. However, the use of a customized imaging guide method was overall significantly superior to a standard film holder method in terms of obtaining perfect or acceptable images with only one exposure. © 2011 John Wiley & Sons A/S.

Investigation on growth, structural, optical, electrical and X-ray sensing properties of chemically deposited zinc bismuth sulfide (ZnxBi2‑xS3) thin films

NASA Astrophysics Data System (ADS)

Sabarish, R.; Suriyanarayanan, N.; Kalita, J. M.; Sarma, M. P.; Wary, G.

2018-05-01

In the present work, ZnxBi2‑xS3 films were synthesized (x = 0.2 M) by a chemical bath deposition (CBD) technique at different bath temperatures (60 °C, 70 °C and 80 °C). The role of bath temperature on the formation of the films has been examined. The crystalline nature, structural parameters and surface morphology of the films were ascertained using x-ray diffraction (XRD), Raman spectroscopy and scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDS) respectively. These studies confirmed the formation of crystalline Zn0.2Bi1.8S3 films with uniform distribution of homogenous grains. The characterization results revealed that the film deposited at 70 °C has the good crystalline quality than the films deposited at 60 and 80 °C. Further, the optical absorption spectra showed that the bandgap (E g ) of the film deposited at 70 °C was about 2.39 eV which was found to be less than the same film deposited at 60 and 80 °C. The Current-Voltage (I-V) characteristics of all the films were measured under dark condition. This showed that the electrical conductivity of the film deposited at 70 °C was 1.61 × 10‑5 S cm‑1 which is ten times higher than other films. Further, the I-V characteristics of the film deposited at 70 °C was studied under x-ray radiation. The current under the x-ray radiation was significantly higher compared to the dark current. The x-ray detection sensitivity of the film was found to be maximum at 0.7 V and gradually decreases with increase of bias voltage. This analysis reveals that the film deposited at 70 °C can be used as an x-ray sensor.

X-ray diffraction analysis of residual stresses in textured ZnO thin films

NASA Astrophysics Data System (ADS)

Dobročka, E.; Novák, P.; Búc, D.; Harmatha, L.; Murín, J.

2017-02-01

Residual stresses are commonly generated in thin films during the deposition process and can influence the film properties. Among a number of techniques developed for stress analysis, X-ray diffraction methods, especially the grazing incidence set-up, are of special importance due to their capability to analyze the stresses in very thin layers as well as to investigate the depth variation of the stresses. In this contribution a method combining multiple {hkl} and multiple χ modes of X-ray diffraction stress analysis in grazing incidence set-up is used for the measurement of residual stress in strongly textured ZnO thin films. The method improves the precision of the stress evaluation in textured samples. Because the measurements are performed at very low incidence angles, the effect of refraction of X-rays on the measured stress is analyzed in details for the general case of non-coplanar geometry. It is shown that this effect cannot be neglected if the angle of incidence approaches the critical angle. The X-ray stress factors are calculated for hexagonal fiber-textured ZnO for the Reuss model of grain-interaction and the effect of texture on the stress factors is analyzed. The texture in the layer is modelled by Gaussian distribution function. Numerical results indicate that in the process of stress evaluation the Reuss model can be replaced by much simpler crystallite group method if the standard deviation of Gaussian describing the texture is less than 6°. The results can be adapted for fiber-textured films of various hexagonal materials.

Synchrotron X-ray Microdiffraction Analysis of Proton Irradiated Polycrystalline Diamond Films

NASA Technical Reports Server (NTRS)

Newton, R. I.; Davidson, J. L.; Ice, G. E.; Liu, W.

2004-01-01

X-ray microdiffraction is a non-destructive technique that allows for depth-resolved, strain measurements with sub-micron spatial resolution. These capabilities make this technique promising for understanding the mechanical properties of MicroElectroMechanical Systems (MEMS). This investigation examined the local strain induced by irradiating a polycrystalline diamond thin film with a dose of 2x10(exp 17) H(+)per square centimeter protons. Preliminary results indicate that a measurable strain, on the order of 10(exp -3), was introduced into the film near the End of Range (EOR) region of the protons.

Erosion of fluorinated diamond-like carbon films by exposure to soft X-rays

NASA Astrophysics Data System (ADS)

Kanda, Kazuhiro; Takamatsu, Hiroki; Miura-Fujiwara, Eri; Akasaka, Hiroki; Saiga, Akihiro; Tamada, Koji

2018-04-01

The effects of soft X-ray irradiation on fluorinated diamond-like carbon (F-DLC) films were investigated using synchrotron radiation (SR). The Vickers hardness of the F-DLC films substantially increased from an initial value of about 290 to about 800 HV at a dose of 50 mA·h and the remained constant at about 1100 HV at doses of more than 300 mA·h. This dose dependence was consistent with those of the film thickness and elemental composition. The depth profile of the elemental composition inside each F-DLC film obtained by the measurement of the X-ray photoelectron spectrum (XPS) during sputtering showed that the composition ratio of fluorine was approximately constant from the surface to the neighborhood of the substrate. Namely, fluorine atoms were desorbed by SR irradiation from not only the surface but also the substrate neighborhood. Modification by SR irradiation was found to occur in the entire F-DLC film of about 200 nm thickness.

[Development and prospect on skeletal age evaluation methods of X-ray film].

PubMed

Wang, Ya-hui; Zhu, Guang-you; Qiao, Ke; Bian, Shi-zhong; Fan, Li-hua; Cheng, Yi-bin; Ying, Chong-liang; Shen, Yan

2007-10-01

The traditional methods of skeletal age estimation mainly include Numeration, Atlas, and Counting scores. In recent years, other new methods were proposed by several scholars. Utilizing image logical characteristics of X-ray film to extrapolate skeletal age is a key means by present forensic medicine workers in evaluating skeletal age. However, there exist some variations when we present the conclusion of skeletal age as an "evidence" directly to the Justice Trial Authority. In order to enhance the accuracy of skeletal age determination, further investigation for appropriate methodology should be undertaken. After a collective study of pertinent domestic and international literatures, we present this review of the research and advancement on skeletal age evaluation methods of X-ray film.

X-ray diffraction characterization of epitaxial CVD diamond films with natural and isotopically modified compositions

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

Prokhorov, I. A., E-mail: igor.prokhorov@mail.ru; Voloshin, A. E.; Ralchenko, V. G.

2016-11-15

Comparative investigations of homoepitaxial diamond films with natural and modified isotopic compositions, grown by chemical vapor deposition (CVD) on type-Ib diamond substrates, are carried out using double-crystal X-ray diffractometry and topography. The lattice mismatch between the substrate and film is precisely measured. A decrease in the lattice constant on the order of (Δa/a){sub relax} ∼ (1.1–1.2) × 10{sup –4} is recorded in isotopically modified {sup 13}C (99.96%) films. The critical thicknesses of pseudomorphic diamond films is calculated. A significant increase in the dislocation density due to the elastic stress relaxation is revealed by X-ray topography.

Abdominal x-ray

MedlinePlus

... are, or may be, pregnant. Alternative Names Abdominal film; X-ray - abdomen; Flat plate; KUB x-ray ... Guidelines Viewers & Players MedlinePlus Connect for EHRs For Developers U.S. National Library of Medicine 8600 Rockville Pike, ...

Practical aspects of the use of the X(2) holder for HRTEM-quality TEM sample preparation by FIB.

PubMed

van Mierlo, Willem; Geiger, Dorin; Robins, Alan; Stumpf, Matthias; Ray, Mary Louise; Fischione, Paul; Kaiser, Ute

2014-12-01

The X(2) holder enables the effective production of thin, electron transparent samples for high-resolution transmission electron microscopy (HRTEM). Improvements to the X(2) holder for high-quality transmission electron microscopy (TEM) sample preparation are presented in this paper. We discuss the influence of backscattered electrons (BSE) from the sample holder in determining the lamella thickness in situ and demonstrate that a significant improvement in thickness determination can be achieved by comparatively simple means using the relative BSE intensity. We show (using Monte Carlo simulations) that by taking into account the finite collection angle of the electron backscatter detector, an approximately 20% underestimation of the lamella thickness in a silicon sample can be avoided. However, a correct thickness determination for light-element lamellas still remains a problem with the backscatter method; we introduce a more accurate method using the energy dispersive X-ray spectroscopy (EDX) signal for in situ thickness determination. Finally, we demonstrate how to produce a thin lamella with a nearly damage-free surface using the X(2) holder in combination with sub-kV polishing in the Fischione Instruments׳ NanoMill(®) TEM specimen preparation system. Copyright © 2014 Elsevier B.V. All rights reserved.

Thin-film-based scintillators for hard x-ray microimaging detectors: the ScinTAX Project

NASA Astrophysics Data System (ADS)

Rack, A.; Cecilia, A.; Douissard, P.-A.; Dupré, K.; Wesemann, V.; Baumbach, T.; Couchaud, M.; Rochet, X.; Riesemeier, H.; Radtke, M.; Martin, T.

2014-09-01

The project ScinTAX developed novel thin scintillating films for the application in high performance X-ray imaging and subsequent introduced new X-ray detectors to the market. To achieve this aim lutetium orthosilicate (LSO) scintillators doped with different activators were grown successfully by liquid phase epitaxy. The high density of LSO (7.4 g/cm3), the effective atomic number (65.2) and the high light yield make this scintillator highly applicable for indirect X-ray detection in which the ionizing radiation is converted into visible light and then registered by a digital detector. A modular indirect detection system has been developed to fully exploit the potential of this thin film scintillator for radiographic and tomographic imaging. The system is compatible for high-resolution imaging with moderate dose as well as adaptable to intense high-dose applications where radiation hard microimaging detectors are required. This proceedings article shall review the achieved performances and technical details on this high-resolution detector system which is now available. A selected example application demonstrates the great potential of the optimized detector system for hard X-ray microimaging, i.e. either to improve image contrast due to the availability of efficient thin crystal films or to reduce the dose to the sample.

Image alignment for tomography reconstruction from synchrotron X-ray microscopic images.

PubMed

Cheng, Chang-Chieh; Chien, Chia-Chi; Chen, Hsiang-Hsin; Hwu, Yeukuang; Ching, Yu-Tai

2014-01-01

A synchrotron X-ray microscope is a powerful imaging apparatus for taking high-resolution and high-contrast X-ray images of nanoscale objects. A sufficient number of X-ray projection images from different angles is required for constructing 3D volume images of an object. Because a synchrotron light source is immobile, a rotational object holder is required for tomography. At a resolution of 10 nm per pixel, the vibration of the holder caused by rotating the object cannot be disregarded if tomographic images are to be reconstructed accurately. This paper presents a computer method to compensate for the vibration of the rotational holder by aligning neighboring X-ray images. This alignment process involves two steps. The first step is to match the "projected feature points" in the sequence of images. The matched projected feature points in the x-θ plane should form a set of sine-shaped loci. The second step is to fit the loci to a set of sine waves to compute the parameters required for alignment. The experimental results show that the proposed method outperforms two previously proposed methods, Xradia and SPIDER. The developed software system can be downloaded from the URL, http://www.cs.nctu.edu.tw/~chengchc/SCTA or http://goo.gl/s4AMx.

Sputter deposition of PZT piezoelectric films on thin glass substrates for adjustable x-ray optics.

PubMed

Wilke, Rudeger H T; Johnson-Wilke, Raegan L; Cotroneo, Vincenzo; Davis, William N; Reid, Paul B; Schwartz, Daniel A; Trolier-McKinstry, Susan

2013-05-10

Piezoelectric PbZr(0.52)Ti(0.48)O(3) (PZT) thin films deposited on thin glass substrates have been proposed for adjustable optics in future x-ray telescopes. The light weight of these x-ray optics enables large collecting areas, while the capability to correct mirror figure errors with the PZT thin film will allow much higher imaging resolution than possible with conventional lightweight optics. However, the low strain temperature and flexible nature of the thin glass complicate the use of chemical-solution deposition due to warping of the substrate at typical crystallization temperatures for the PZT. RF magnetron sputtering enabled preparation of PZT films with thicknesses up to 3 μm on Schott D263 glass substrates with much less deformation. X-ray diffraction analysis indicated that the films crystallized with the perovskite phase and showed no indication of secondary phases. Films with 1 cm(2) electrodes exhibited relative permittivity values near 1100 and loss tangents below 0.05. In addition, the remanent polarization was 26 μC/cm(2) with coercive fields of 33 kV/cm. The transverse piezoelectric coefficient was as high as -6.1±0.6 C/m(2). To assess influence functions for the x-ray optics application, the piezoelectrically induced deflection of individual cells was measured and compared with finite-element-analysis calculations. The good agreement between the results suggests that actuation of PZT thin films can control mirror figure errors to a precision of about 5 nm, allowing sub-arcsecond imaging.

Crystalline Stratification in Semiconducting Polymer Thin Film Quantified by Grazing Incidence X-ray Scattering

NASA Astrophysics Data System (ADS)

Gann, Eliot; Caironi, Mario; Noh, Yong-Young; Kim, Yun-Hi; McNeill, Christopher R.

The depth dependence of crystalline structure within thin films is critical for many technological applications, but has been impossible to measure directly using common techniques. In this work, by monitoring diffraction peak intensity and location and utilizing the highly angle-dependent waveguiding effects of X-rays near grazing incidence we quantitatively measure the thickness, roughness and orientation of stratified crystalline layers within thin films of a high-performance semiconducting polymer. In particular, this diffractive X-ray waveguiding reveals a self-organized 5-nm-thick crystalline surface layer with crystalline orientation orthogonal to the underlying 65-nm-thick layer. While demonstrated for an organic semiconductor film, this approach is applicable to any thin film material system where stratified crystalline structure and orientation can influence important interfacial processes such as charge injection and field-effect transport.

High-Resolution Detector For X-Ray Diffraction

NASA Technical Reports Server (NTRS)

Carter, Daniel C.; Withrow, William K.; Pusey, Marc L.; Yost, Vaughn H.

1988-01-01

Proposed x-ray-sensitive imaging detector offers superior spatial resolution, counting-rate capacity, and dynamic range. Instrument based on laser-stimulated luminescence and reusable x-ray-sensitive film. Detector scans x-ray film line by line. Extracts latent image in film and simultaneously erases film for reuse. Used primarily for protein crystallography. Principle adapted to imaging detectors for electron microscopy and fluorescence spectroscopy and general use in astronomy, engineering, and medicine.

In situ x-ray diffraction observation of multiple texture turnovers in sputtered Cr films

NASA Astrophysics Data System (ADS)

Zhao, Z. B.; Rek, Z. U.; Yalisove, S. M.; Bilello, J. C.

2004-11-01

A series of Cr films were deposited onto native oxides of (100) Si substrates via a confocal deposition geometry in a magnetron sputter chamber. The film growth chamber was incorporated with an in situ x-ray diffraction system, which allowed the collection of x-ray diffraction data on the growing film in a quasi real time fashion without interruption of film deposition. The in situ x-ray diffraction, coupled with other ex situ characterization techniques, was used to study structural evolutions of the Cr films deposited at various Ar pressures. It was observed that the evolution of the crystallographic structures of Cr films was very sensitive to both deposition conditions and film thickness. With the confocal deposition geometry, the Cr films developed various types of out-of-plane textures. In addition to the (110) and (100) types of textures commonly reported for vapor deposited Cr films, the (111) and (112) types of textures were also observed. The film deposited at low Ar pressure (2 mTorr) developed strong (111) type texture. With the increase in either Ar pressure or film thickness, the Cr films tended to develop (112) and (100) types of texture. At high Ar pressures (>10 mTorr), several changes in texture type with increasing film thickness were observed. The sequence can be described as (110)-->(112)-->(100). The strong tendency for these films to ultimately assume the (100) type of texture could be related to significant rises in substrate temperatures during the late stages of film growth with high Ar pressures. The observation of the multiple texture type changes suggests that the evolution of Cr films is controlled by complex growth kinetics. The competitive growth of grains with different orientations can be altered not only by controllable deposition parameters such as Ar pressure, but also by the variations of in situ film attributes (e.g., residual stress and substrate temperature) occurring concurrently with film growth.

Crossover And MTF Characteristics Of A Tabular-Grain X-Ray Film

NASA Astrophysics Data System (ADS)

Huff, K. E.; Wagner, P. W.

1984-08-01

An orthochromatic x-ray film made with tabular silver halide grains has a significantly higher MTF when exposed with green-emitting intensifying screens than do conventional films with similar sensitometric properties. The primary reason for the improved MTF is a decrease in the amount of crossover exposure, i.e., exposure by light that has crossed the support one or more times. Two well-established sensitometric procedures for measuring crossover have been compared. One produces results accurate enough for calculations of MTF relationships. Calculated MTF relationships for tabulargrain and conventional films are compared with measured values.

Surface Morphology of Liquid and Solid Thin Films via X-Ray Reflectivity.

NASA Astrophysics Data System (ADS)

Shindler, Joseph Daniel

X-ray reflectivity can be used to measure the spatial variations in the electron density on length scales from Angstroms to microns. It is sensitive to atomic scale roughness, interdiffusion in buried layers, the thickness of multilayer stacks, and in-plane correlations in each of these cases. We have pioneered the use of a high intensity, moderate resolution configuration for x-ray reflectivity which utilizes a bent crystal graphite monochromator. With this technique we can obtain a beam intensity one hundred times greater than is possible using the high resolution rotating anode configuration, while we have shown that the resulting instrumental resolution is appropriate for the vast majority of thin film work. For all of the systems studied, we were able to measure the weak diffuse scattering signal to probe the in-plane length scales of interfacial roughness, a measurement which had previously only been attempted at synchrotron sources. Studied systems include thin films and surfaces with a wide range of structural order and surface morphologies. Interest in liquid films has been of a fundamental nature. Theories on the expected film evolution with changing thickness and temperature are currently being tested with scattering experiments. We have pursued the issues of film/substrate wetting and conformality, focussing on the temperature dependence of these phenomena near the triple point. Despite the heterogeneity of the substrate potential, we see a very sharp wetting transition at or near the triple point, although below the triple point the film is still smooth, consistent with a uniform layer. We also see a loss of conformality as the fluid films thicken; this is consistent with theory and with other recent experiments. The properties of a multilayer solid film depend not only on the magnitude of the roughness of each interface, but also on the conformality between interfaces and the length scales of the roughness--i.e., whether the roughness is on the atomic

Synchrotron X-ray studies of epitaxial ferroelectric thin films and nanostructures

NASA Astrophysics Data System (ADS)

Klug, Jeffrey A.

The study of ferroelectric thin films is a field of considerable scientific and technological interest. In this dissertation synchrotron x-ray techniques were applied to examine the effects of lateral confinement and epitaxial strain in ferroelectric thin films and nanostructures. Three materials systems were investigated: laterally confined epitaxial BiFeO3 nanostructures on SrTiO3 (001), ultra-thin commensurate SrTiO 3 films on Si (001), and coherently strained films of BaTiO3 on DyScO3 (110). Epitaxial films of BiFeO3 were deposited by radio frequency magnetron sputtering on SrRuO3 coated SrTiO 3 (001) substrates. Laterally confined nanostructures were fabricated using focused ion-beam processing and subsequently characterized with focused beam x-ray nanodiffraction measurements with unprecedented spatial resolution. Results from a series of rectangular nanostructures with lateral dimensions between 500 nm and 1 mum and a comparably-sized region of the unpatterned BiFeO3 film revealed qualitatively similar distributions of local strain and lattice rotation with a 2-3 times larger magnitude of variation observed in those of the nanostructures compared to the unpatterned film. This indicates that lateral confinement leads to enhanced variation in the local strain and lattice rotation fields in epitaxial BiFeO3 nanostructures. A commensurate 2 nm thick film of SrTiO3 on Si was characterized by the x-ray standing wave (XSW) technique to determine the Sr and Ti cation positions in the strained unit cell in order to verify strain-induced ferroelectricity in SrTiO3/Si. A Si (004) XSW measurement at 10°C indicated that the average Ti displacement from the midpoint between Sr planes was consistent in magnitude to that predicted by a density functional theory (DFT) calculated ferroelectric structure. The Ti displacement determined from a 35°C measurement better matched a DFT-predicted nonpolar structure. The thin film extension of the XSW technique was employed to

Study on growth of large area mercuric iodide polycrystalline film and its x-ray imaging

NASA Astrophysics Data System (ADS)

Xu, Gang; Guo, Yanfei; Xi, Zengzhe; Gu, Zhi; Zhang, Lan; Yu, Wentao; Ma, Xuming; Li, Bo

2014-11-01

Tetragonal mercuric iodide, as a group of wide band gap semiconductors, has been widely investigation during most of the last half-century, applied on room-temperature X-ray and gamma-ray spectrometers. Up to the present, Mercuric iodide (HgI2) is still thought to be one of the most outstanding vitality semiconductor materials because of its wide band gap, for which the device was required to be high resistivity, high atomic number, adequate mechanical strength, long carrier lifetimes and high mobility-lifetime produces. Now, HgI2 polycrystalline films are being developed as a new detector technology for digital x-ray imaging. In this research, HgI2 polycrystalline films with different surface areas of 1 and 36 cm2 were grown by vapor sublimation method within a self-design growth furnace. XRD, SEM and J-V analysis were used to characterize the properties of these as-grown films. The results of XRD show that the ratio of (001) / (hkl) on all as-grown films is amount to be 90% for the area of 1 cm2 films. Grain size of 1 cm2 films was measured to be 120-150 μm. Their electrical resistivity were also determined to be about 1011 Ω·cm operated at the bias voltage of ~100 V by I-V characteristic measurement. Utilizing the polycrystalline film with the area of 36 cm2 deposited on TFT, we then prepared the direct image detector after capsulation for non-corrosive steel screw imaging. The results indicated that profile of screw was distinctly exhibited in digital x-ray imaging systems.

Depth resolved compositional analysis of aluminium oxide thin film using non-destructive soft x-ray reflectivity technique

NASA Astrophysics Data System (ADS)

Sinha, Mangalika; Modi, Mohammed H.

2017-10-01

In-depth compositional analysis of 240 Å thick aluminium oxide thin film has been carried out using soft x-ray reflectivity (SXR) and x-ray photoelectron spectroscopy technique (XPS). The compositional details of the film is estimated by modelling the optical index profile obtained from the SXR measurements over 60-200 Å wavelength region. The SXR measurements are carried out at Indus-1 reflectivity beamline. The method suggests that the principal film region is comprised of Al2O3 and AlOx (x = 1.6) phases whereas the interface region comprised of SiO2 and AlOx (x = 1.6) mixture. The soft x-ray reflectivity technique combined with XPS measurements explains the compositional details of principal layer. Since the interface region cannot be analyzed with the XPS technique in a non-destructive manner in such a case the SXR technique is a powerful tool for nondestructive compositional analysis of interface region.

Elastohydrodynamic film thickness formula based on X-ray measurements with a synthetic paraffinic oil

NASA Technical Reports Server (NTRS)

Loewenthal, S. H.; Parker, R. J.; Zaretsky, E. V.

1973-01-01

An empirical elastohydrodynamic film thickness formula for heavily loaded contacts based upon X-ray film thickness measurements made with a synthetic paraffinic oil is presented. The deduced relation was found to adequately reflect the high load dependence exhibited by the measured minimum film thickness data at high Hertizian contact stresses, that is, above 1.04 x 10 to the ninth N/sq m (150,000 psi). Comparisons were made with the numerical results from a theoretical isothermal film thickness formula. The effects of changes in contact geometry, material, and lubricant properties on the form of the empirical model are also discussed.

Topographic measurement of buried thin-film interfaces using a grazing resonant soft x-ray scattering technique

NASA Astrophysics Data System (ADS)

Gann, Eliot; Watson, Anne; Tumbleston, John R.; Cochran, Justin; Yan, Hongping; Wang, Cheng; Seok, Jaewook; Chabinyc, Michael; Ade, Harald

2014-12-01

The internal structures of thin films, particularly interfaces between different materials, are critical to system properties and performance across many disciplines, but characterization of buried interface topography is often unfeasible. In this work, we demonstrate that grazing resonant soft x-ray scattering (GRSoXS), a technique measuring diffusely scattered soft x rays from grazing incidence, can reveal the statistical topography of buried thin-film interfaces. By controlling and predicting the x-ray electric field intensity throughout the depth of the film and simultaneously the scattering contrast between materials, we are able to unambiguously identify the microstructure at different interfaces of a model polymer bilayer system. We additionally demonstrate the use of GRSoXS to selectively measure the topography of the surface and buried polymer-polymer interface in an organic thin-film transistor, revealing different microstructure and markedly differing evolution upon annealing. In such systems, where only indirect control of interface topography is possible, accurate measurement of the structure of interfaces for feedback is critically important. While we demonstrate the method here using organic materials, we also show that the technique is readily extendable to any thin-film system with elemental or chemical contrasts exploitable at absorption edges.

Design of a diamond-crystal monochromator for the LCLS hard x-ray self-seeding project

NASA Astrophysics Data System (ADS)

Shu, D.; Shvyd'ko, Y.; Amann, J.; Emma, P.; Stoupin, S.; Quintana, J.

2013-03-01

As the result of collaborations between the Advanced Photon Source (APS), Argonne National Laboratory, and the Linac Coherent Light Source (LCLS) at SLAC National Accelerator Laboratory, we have designed and constructed a diamond crystal monochromator for the LCLS hard x-ray self-seeding project. The novel monochromator is ultrahigh-vacuum compatible to meet the LCLS linear accelerator vacuum environmental requirement. A special graphite holder was designed for strain-free mount of the 110-μm thin synthetic diamond crystal plate provided by Technological Institute for Super-hard and Novel Carbon Materials of Russia (TISNCM). An in-vacuum multi-axis precision positioning mechanism is designed to manipulate the thin-film diamond holder with resolutions and stabilities required by the hard x-ray self-seeding physics. Optical encoders, limit switches, and hardware stops are established in the mechanism to ensure system reliability and to meet the accelerator personal and equipment safety interlock requirements. Molybdenum shields are installed in the monochromator to protect the encoders and associated electronics from radiation damage. Mechanical specifications, designs, and preliminary test results of the diamond monochromator are presented in this paper.

X-ray absorption fine structure and x-ray diffraction studies of crystallographic grains in nanocrystalline FePd:Cu thin films

NASA Astrophysics Data System (ADS)

Krupinski, M.; Perzanowski, M.; Polit, A.; Zabila, Y.; Zarzycki, A.; Dobrowolska, A.; Marszalek, M.

2011-03-01

FePd alloys have recently attracted considerable attention as candidates for ultrahigh density magnetic storage media. In this paper we investigate FePd thin alloy film with a copper admixture composed of nanometer-sized grains. [Fe(0.9 nm)/Pd(1.1 nm)/Cu(d nm)]×5 multilayers were prepared by thermal deposition at room temperature in UHV conditions on Si(100) substrates covered by 100 nm SiO2. The thickness of the copper layer has been changed from 0 to 0.4 nm. After deposition, the multilayers were rapidly annealed at 600 °C in a nitrogen atmosphere, which resulted in the creation of the FePd:Cu alloy. The structure of alloy films obtained this way was determined by x-ray diffraction (XRD), glancing angle x-ray diffraction, and x-ray absorption fine structure (EXAFS). The measurements clearly showed that the L10 FePd:Cu nanocrystalline phase has been formed during the annealing process for all investigated copper compositions. This paper concentrates on the crystallographic grain features of FePd:Cu alloys and illustrates that the EXAFS technique, supported by XRD measurements, can help to extend the information about grain size and grain shape of poorly crystallized materials. We show that, using an appropriate model of the FePd:Cu grains, the comparison of EXAFS and XRD results gives a reasonable agreement.

Contact x-ray microscopy using Asterix

NASA Astrophysics Data System (ADS)

Conti, Aldo; Batani, Dimitri; Botto, Cesare; Masini, Alessandra; Bernardinello, A.; Bortolotto, Fulvia; Moret, M.; Poletti, G.; Piccoli, S.; Cotelli, F.; Lora Lamia Donin, C.; Stead, Anthony D.; Marranca, A.; Eidmann, Klaus; Flora, Francesco; Palladino, Libero; Reale, Lucia

1997-10-01

The use of a high energy laser source for soft x-ray contact microscopy is discussed. Several different targets were used and their emission spectra compared. The x-ray emission, inside and outside the Water Window, was characterized in detail by means of many diagnostics, including pin hole and streak cameras. Up to 12 samples holders per shot were exposed thanks to the large x-ray flux and the geometry of the interaction chamber. Images of several biological samples were obtained, including Chlamydomonas and Crethidia green algae, fish and boar sperms and Saccharomyces Cerevisiae yeast cells. A 50 nm resolution was reached on the images of boar sperm. Original information concerning the density of inner structures of Crethidia green algae were obtained.

X-Ray Detection Visits the Classroom

ERIC Educational Resources Information Center

Peralta, Luis; Farinha, Ana; Pinto, Ana

2008-01-01

Film has been used to detect x-rays since the early days of their discovery by Rontgen. Although nowadays superseded by other techniques, film still provides a cheap means of x-ray detection, making it attractive in high-school or undergraduate university courses. If some sort of quantitative result is required, the film's optical absorbance or…

Dose-response curve of EBT, EBT2, and EBT3 radiochromic films to synchrotron-produced monochromatic x-ray beams

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

Brown, Thomas A. D.; Hogstrom, Kenneth R.; Alvarez, Diane

Purpose: This work investigates the dose-response curves of GAFCHROMIC{sup Registered-Sign} EBT, EBT2, and EBT3 radiochromic films using synchrotron-produced monochromatic x-ray beams. EBT2 film is being utilized for dose verification in photoactivated Auger electron therapy at the Louisiana State University Center for Advanced Microstructures and Devices (CAMD) synchrotron facility. Methods: Monochromatic beams of 25, 30, and 35 keV were generated on the tomography beamline at CAMD. Ion chamber depth-dose measurements were used to determine the dose delivered to films irradiated at depths from 0.7 to 8.5 cm in a 10 Multiplication-Sign 10 Multiplication-Sign 10-cm{sup 3} polymethylmethacrylate phantom. AAPM TG-61 protocol wasmore » applied to convert measured ionization into dose. Films were digitized using an Epson 1680 Professional flatbed scanner and analyzed using the net optical density (NOD) derived from the red channel. A dose-response curve was obtained at 35 keV for EBT film, and at 25, 30, and 35 keV for EBT2 and EBT3 films. Calibrations of films for 4 MV x-rays were obtained for comparison using a radiotherapy accelerator at Mary Bird Perkins Cancer Center. Results: The sensitivity (NOD per unit dose) of EBT film at 35 keV relative to that for 4-MV x-rays was 0.73 and 0.76 for doses 50 and 100 cGy, respectively. The sensitivity of EBT2 film at 25, 30, and 35 keV relative to that for 4-MV x-rays varied from 1.09-1.07, 1.23-1.17, and 1.27-1.19 for doses 50-200 cGy, respectively. For EBT3 film the relative sensitivity was within 3% of unity for all three monochromatic x-ray beams. Conclusions: EBT and EBT2 film sensitivity showed strong energy dependence over an energy range of 25 keV-4 MV, although this dependence becomes weaker for larger doses. EBT3 film shows weak energy dependence, indicating that it would be a better dosimeter for kV x-ray beams where beam hardening effects can result in large changes in the effective energy.« less

Technique charts for Kodak EC-L film screen system for portal localization in a 6MV X-ray beam.

PubMed

Sandilos, P; Antypas, C; Paraskevopoulou, C; Kouvaris, J; Vlachos, L

2006-01-01

Port films are used in radiotherapy for visual evaluation of the radiation fields and subsequent quantitative analysis. Common port films suffer from poor image quality compared to the simulator-diagnostic films and is desirable to determine the appropriate exposure required for the best image contrast. The aim of this work is to generate technique charts for the Kodak EC-L film screen system for use in a 6MV x-ray beam. Three homogeneous water phantoms were used to simulate head-neck, thorax and abdomen dimensions of adult human, correspondingly. The film screen system was calibrated in a 6MV x-ray beam and under various irradiation conditions. The film screen system behavior was studied as a function of phantom thickness, field size and air gap between the phantom and the film screen system. In each case the optimum film exposure which produces the maximum image contrast was determined. The generated technique charts for the EC-L film screen system and for a 6 MV x-ray beam are used in our radiotherapy department for daily quality assurance of the radiotherapy procedure.

Mechanical design of thin-film diamond crystal mounting apparatus for coherence preservation hard x-ray optics

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

Shu, Deming, E-mail: shu@aps.anl.gov; Shvyd’ko, Yuri V.; Stoupin, Stanislav

2016-07-27

A new thin-film diamond crystal mounting apparatus has been designed at the Advanced Photon Source (APS) for coherence preservation hard x-ray optics with optimized thermal contact and minimized crystal strain. This novel mechanical design can be applied to new development in the field of: x-ray optics cavities for hard x-ray free-electron laser oscillators (XFELOs), self-seeding monochromators for hard x-ray free-electron laser (XFEL) with high average thermal loading, high heat load diamond crystal monochromators and beam-sharing/beam-split-and-delay devices for XFEL facilities and future upgraded high-brightness coherent x-ray source in the MBA lattice configuration at the APS.

Synchrotron X-ray studies of model SOFC cathodes, part I: Thin film cathodes

DOE PAGES

Chang, Kee-Chul; Ingram, Brian; Ilavsky, Jan; ...

2017-10-14

In this work, we present synchrotron x-ray investigations of thin film La 0.6Sr 0.4Co 0.2Fe 0.8O 3-δ (LSCF) model cathodes for solid oxide fuel cells, grown on electrolyte substrates by pulse laser deposition, in situ during half-cell operations. We observed dynamic segregations of cations, such as Sr and Co, on the surfaces of the film cathodes. The effects of temperature, applied potentials, and capping layers on the segregations were investigated using a surfacesensitive technique of total external reflection x-ray fluorescence. We also studied patterned thin film LSCF cathodes using high-resolution micro-beam diffraction measurements. We find chemical expansion decreases for narrowmore » stripes. This suggests the expansion is dominated by the bulk pathway reactions. Lastly, the chemical expansion vs. the distance from the electrode contact was measured at three temperatures and an oxygen vacancy activation energy was estimated to be ~1.4 eV.« less

X ray, extreme and far ultraviolet optical thin films for space applications

NASA Technical Reports Server (NTRS)

Zukic, Muamer; Torr, Douglas G.; Kim, Jongmin

1993-01-01

Far and extreme ultraviolet optical thin film filters find many uses in space astronomy, space astrophysics, and space aeronomy. Spacebased spectrographs are used for studying emission and absorption features of the earth, planets, sun, stars, and the interstellar medium. Most of these spectrographs use transmission or reflection filters. This requirement has prompted a search for selective filtering coatings with high throughput in the FUV and EUV spectral region. Important progress toward the development of thin film filters with improved efficiency and stability has been made in recent years. The goal for this field is the minimization of absorption to get high throughput and enhancement of wavelength selection. The Optical Aeronomy Laboratory (OAL) at the University of Alabama in Huntsville has recently developed the technology to determine optical constants of bulk and film materials for wavelengths extending from x-rays (0.1 nm) to the FUV (200 nm), and several materials have been identified that were used for designs of various optical devices which previously have been restricted to space application in the visible and near infrared. A new design concept called the Pi-multilayer was introduced and applied to the design of optical coatings for wavelengths extending from x-rays to the FUV. Section 3 of this report explains the Pi-multilayer approach and demonstrates its application for the design and fabrication of the FUV coatings. Two layer Pi-stacks have been utilized for the design of reflection filters in the EUV wavelength range from 70 - 100 nm. In order to eliminate losses due to the low reflection of the imaging optics and increase throughput and out-of-band rejection of the EUV instrumentation we introduced a self-filtering camera concept. In the FUV region, MgF2 and LiF crystals are known to be birefringent. Transmission polarizers and quarterwave retarders made of MgF2 or LiF crystals are commercially available but the performances are poor. New

Broadband X-ray edge-enhancement imaging of a boron fibre on lithium fluoride thin film detector

NASA Astrophysics Data System (ADS)

Nichelatti, E.; Bonfigli, F.; Vincenti, M. A.; Cecilia, A.; Vagovič, P.; Baumbach, T.; Montereali, R. M.

2016-10-01

The white beam (∼6-80 keV) available at the TopoTomo X-ray beamline of the ANKA synchrotron facility (KIT, Karlsruhe, Germany) was used to perform edge-enhancement imaging tests on lithium fluoride radiation detectors. The diffracted X-ray image of a microscopic boron fibre, consisting of tungsten wire wrapped by boron cladding, was projected onto lithium fluoride thin films placed at several distances, from contact to 1 m . X-ray photons cause the local formation of primary and aggregate colour centres in lithium fluoride; these latter, once illuminated under blue light, luminesce forming visible-light patterns-acquired by a confocal laser scanning microscope-that reproduce the intensity of the X-ray diffracted images. The tests demonstrated the excellent performances of lithium fluoride films as radiation detectors at the investigated photon energies. The experimental results are here discussed and compared with those calculated with a model that takes into account all the processes that concern image formation, storing and readout.

Evaluating structure in thin block copolymer films with soft x-rays (Conference Presentation)

NASA Astrophysics Data System (ADS)

Sunday, Daniel; Liman, Christopher; Hannon, Adam F.; Ren, Jiaxing; Chen, Xuanxuan; Suh, Hyo Seon; de Pablo, Juan J.; Nealey, Paul F.; Kline, R. Joseph

2017-03-01

The semiconductor industry is evaluating a variety of approaches for the cost efficient production of future processing and memory generations. Amongst the technologies being explored are multiple patterning steps, extreme ultraviolet (EUV) lithography, multiple-beam electron beam lithography and the directed self-assembly (DSA) of block copolymers (BCPs). BCP DSA utilizes a chemical or topographical template to induce long range order in a thin film of BCP which enhances the resolution of the original pattern. The characterization of buried structure within a DSA BCP film is challenging due to the lack of contrast between the organic materials. Critical-dimension small angle x-ray scattering (CDSAXS) measurements were performed on DSA BCP films, using soft X-rays to tune the contrast, in order to understand the relationship between template structure and film morphology.1 The results of these measurements show that as the width of the guiding stripe widens the arrangement of the BCP on the guiding stripe inverts, shifting from the A block being centered on the guiding stripe to the B block being centered on the guiding stripe. The initial results of integration of mean field simulations into the analysis of scattering data will also be discussed. In addition to examining the BCP structure with CDSAXS, soft X-ray reflectivity2 measurements were performed on BCP to better understand the relationship between interface width for systems with alternative architectures (triblocks) and additives (polymers/ionic liquids). The addition of a selectively associating additive increases the interaction parameter between the two blocks, resulting in the reduction of the interface width and access to smaller pitches. The use of soft X-ray reflectivity allows the evaluation of the distribution of the additive. (1) Sunday, D. F.; Hammond, M. R.; Wang, C.; Wu, W.; Delongchamp, D. M.; Tjio, M.; Cheng, J. Y.; Kline, R. J.; Pitera, J. W. Determination of the Internal Morphology of

Effects of gamma-ray irradiation on the optical properties of amorphous Se100-xHgx thin films

NASA Astrophysics Data System (ADS)

Ahmad, Shabir; Islam, Shama; Nasir, Mohd.; Asokan, K.; Zulfequar, M.

2018-06-01

In this study, the thermal quenching technique was employed to prepare bulk samples of Se100-xHgx (x = 0, 5, 10, 15). Thin films with a thickness of ∼250 nm were deposited on glass substrates using the thermal evaporation technique. These films were irradiated with gamma rays at doses of 25-100 kGy. The elemental compositions of the as-deposited thin films were confirmed by energy dispersive X-ray analysis and Rutherford backscattering spectrometry. X-ray diffraction analysis confirmed the crystalline nature of these thin films upto the dose of 75 kGy. Fourier transform-infrared spectroscopy showed that the concentration of defects decreased after gamma irradiation. Microstructural analysis by field emission scanning electron microscopy indicated that the grain size increases after irradiation. Optical study based on spectrophotometry showed that the optical band gap values of these films increase after the addition of Hg whereas they decrease after gamma irradiation. We found that the absorption coefficient increases with doses up to 75 kGy but decreases at higher doses. These remarkable shifts in the optical band gap and absorption coefficient values are interpreted in terms of the creation and annihilation of defects, which are the main effects produced by gamma irradiation.

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

NASA Astrophysics Data System (ADS)

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

2013-03-01

We have developed microstructured Lu2O3:Eu scintillator films capable of providing spatial resolution on the order of micrometers for hard X-ray imaging. In addition to their extraordinary resolution, Lu2O3:Eu films simultaneously provide high absorption efficiency for 20 to 100 keV X-rays, and bright 610 nm emission, with intensity rivalling that of the brightest known scintillators. At present, high spatial resolution of such a magnitude is achieved using ultra-thin scintillators measuring only about 1 to 5 μm in thickness, which limits absorption efficiency to ~3% for 12 keV X-rays and less than 0.1% for 20 to 100 keV X-rays, resulting in excessive measurement time and exposure to the specimen. Lu2O3:Eu would significantly improve that (99.9% @12 keV and 30% @ 70 keV). Important properties and features of our Lu2O3:Eu scintillator material, fabricated by our electron-beam physical vapour deposition (EB-PVD) process, combines superior density of 9.5 g/cm3, microcolumnar structure emitting 48000 photons/MeV whose wavelength is an ideal match for the underlying CCD detector array. We grew thin films measuring 5-50μm in thickness as well as covering areas up to 5 × 5 cm2 which can be a suitable basis for microtomography, digital radiography as well as CT and hard X-ray Micro-Tomography (XMT).

Structural analysis of polymer thin films using GISAXS in the tender X-ray region: Concept and design of GISAXS experiments using the tender X-ray energy at BL-15A2 at the Photon Factory

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

Takagi, H., E-mail: takagih@post.kek.jp; Igarashi, N.; Mori, T.

If small angle X-ray scattering (SAXS) utilizing the soft X-ray region is available, advanced and unique experiments, which differ from traditional SAXS methods, can be realized. For example, grazing-incidence small angle X-ray scattering (GISAXS) using hard X-ray is a powerful tool for understanding the nanostructure in both vertical and lateral directions of thin films, while GISAXS utilizing the tender X-ray region (SX-GISAXS) enables depth-resolved analysis as well as a standard GISAXS analysis in thin films. Thus, at BL-15A2 at the Photon Factory, a dedicated diffractometer for SX-GISAXS (above 2.1 keV) was constructed. This diffractometer is composed of four vacuum chambers andmore » can be converted into the vacuum state from the sample chamber in front of the detector surface. Diffractions are clearly observed until 12th peak when measuring collagen by SAXS with an X-ray energy of 2.40 keV and a camera length of 825 mm. Additionally, we conducted the model experiment using SX-GISAXS with an X-ray energy of 2.40 keV to confirm that a poly(methyl methacrylate)-poly(n-butyl acrylate) block copolymer thin film has a microphase-separated structure in the thin film, which is composed of lamellae aligned both parallel and perpendicular to the substrate surface. Similarly, in a polystyrene-poly(methyl methacrylate) block copolymer thin film, SX-GISAXS with 3.60 keV and 5.73 keV revealed that hexagonally packed cylinders are aligned parallel to the substrate surface. The incident angle dependence of the first order peak position of the q{sub z} direction obtained from experiments at various incident X-ray energies agrees very well with the theoretical one calculated from the distorted wave Born approximation.« less

Retrieving spin textures on curved magnetic thin films with full-field soft X-ray microscopies

DOE PAGES

Streubel, Robert; Kronast, Florian; Fischer, Peter; ...

2015-07-03

X-ray tomography is a well-established technique to characterize 3D structures in material sciences and biology; its magnetic analogue—magnetic X-ray tomography—is yet to be developed. We demonstrate the visualization and reconstruction of magnetic domain structures in a 3D curved magnetic thin films with tubular shape by means of full-field soft X-ray microscopies. In the 3D arrangement of the magnetization is retrieved from a set of 2D projections by analysing the evolution of the magnetic contrast with varying projection angle. By using reconstruction algorithms to analyse the angular evolution of 2D projections provides quantitative information about domain patterns and magnetic coupling phenomenamore » between windings of azimuthally and radially magnetized tubular objects. In conclusion, the present approach represents a first milestone towards visualizing magnetization textures of 3D curved thin films with virtually arbitrary shape.« less

Retrieving spin textures on curved magnetic thin films with full-field soft X-ray microscopies

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

Streubel, Robert; Kronast, Florian; Fischer, Peter

X-ray tomography is a well-established technique to characterize 3D structures in material sciences and biology; its magnetic analogue—magnetic X-ray tomography—is yet to be developed. We demonstrate the visualization and reconstruction of magnetic domain structures in a 3D curved magnetic thin films with tubular shape by means of full-field soft X-ray microscopies. In the 3D arrangement of the magnetization is retrieved from a set of 2D projections by analysing the evolution of the magnetic contrast with varying projection angle. By using reconstruction algorithms to analyse the angular evolution of 2D projections provides quantitative information about domain patterns and magnetic coupling phenomenamore » between windings of azimuthally and radially magnetized tubular objects. In conclusion, the present approach represents a first milestone towards visualizing magnetization textures of 3D curved thin films with virtually arbitrary shape.« less

X-ray diffraction and Raman investigations of thickness dependent stress effects on Pb(ZrxTi1-x)O3 thin films

NASA Astrophysics Data System (ADS)

Lappalainen, Jyrki; Lantto, Vilho; Frantti, Johannes; Hiltunen, Jussi

2006-06-01

Microstructure, film orientation, and optical transmission spectra of polycrystalline Nd-modified Pb(ZrxTi1-x)O3 films were studied as a function of film thickness. Pulsed laser deposition was used for the fabrication of films with thickness from 80to465nm on single-crystal MgO(100) substrates. Raman spectroscopy, x-ray diffraction, and spectrophotometry measurements were utilized in the film characterization. With the decreasing film thickness, films first oriented with c axis perpendicular to film surface, and then, after some critical thickness, changed to a-axis orientation. At the same time, compressive stress increased up to 1.3GPa and a clear blueshift of the optical absorption edge was found in transmission spectra.

Verwey transition in a magnetite ultrathin film by resonant x-ray scattering

NASA Astrophysics Data System (ADS)

Grenier, S.; Bailly, A.; Ramos, A. Y.; De Santis, M.; Joly, Y.; Lorenzo, J. E.; Garaudée, S.; Frericks, M.; Arnaud, S.; Blanc, N.; Boudet, N.

2018-03-01

We report a detailed study of the Verwey transition in a magnetite ultrathin film (UTF) grown on Ag(001) using resonant x-ray scattering (RXS). RXS was measured at the Fe K-edge on the crystal truncation rod of the substrate, increasing the sensitivity to the film thanks to the cross-interference, thereby obtaining an x-ray phase-shift reference and a polarization analyzer. The spectra were interpreted with ad hoc calculations based on density functional theory within a surface-scattering formalism. We observed that the UTF has a relatively sharp transition temperature TV=120 K and is remarkably close to the bulk temperature for such thickness. We determined the specific Fe stacking at the interface with the substrate below TV, and detected a spectroscopic signal evolving with temperature from TV up to at least TV+80 K, hinting that the RT crystallographic structure does not set at TV in the UTF.

Development of x-ray mask in Taiwan

NASA Astrophysics Data System (ADS)

Sheu, Jeng Tzong; Su, Shyang

1996-05-01

This paper presents results of using silicon carbide (SiC) and silicon-rich silicon nitride (SiNx) as membrane for X-ray masks in technology of X-ray lithography. Microcrystalline silicon carbide film was deposited on silicon substrate by electron synchrotron resonance plasma-enhanced chemical vapor deposition at 300 degrees C utilizing a SiH4/CH4/H2/Ar gas mixture. Low tensile stress film which is suitable as X-ray membrane can be achieved by annealing after silicon carbide film deposition. The microwave power over 800 watts and the gas ratio (Methane:Silane) larger than 1.5 are needed for the stoichiometry of SiC film. On the other hand, we deposited silicon-rich silicon nitride film on silicon substrate by low pressure chemical vapor deposition at 850 degrees C to 900 degrees C. In order to get low tensile stress film, different gas flow ratios (Dichlorosilane:Ammonia) were tested. The increased gas flow ratio (Dichlorosilane:Ammonia) and the increased deposition temperature are related to the decrease of tensile stress of film. Roughness, uniformity, optical transmittance and soft X-ray transmission of both films are reported. The absorption bands of both films were measured by FTIR spectroscopy. The surface morphology was monitored by AFM. The photon transmission of both films was measured in the range of 400 to 800 nm for visible light and 800 to 1600 ev photon energy for SR soft X-ray transmission was conducted at the Synchrotron Radiation Research Center, Hsinchu, Taiwan. The deposition rate of both films are 13 nm/min and 40 nm/min for silicon nitride and silicon carbide, respectively.

X-ray photoelectron spectroscopy study of excimer laser treated alumina films

NASA Astrophysics Data System (ADS)

Georgiev, D. G.; Kolev, K.; Laude, L. D.; Mednikarov, B.; Starbov, N.

1998-01-01

Amorphous alumina layers are deposited on a single crystal Si substrate by a e-gun evaporation technique. These films are then thermally annealed in oxygen to be crystallized and, further, irradiated with an excimer laser beam. At each stage of the film preparation, an x-ray photoelectron spectroscopy analysis is performed at the film surface and in depth, upon ion beam grinding. Results give evidence for the formation of an aluminosilicate upon thermal annealing of the film in oxygen. At the surface itself, this compound is observed to decompose upon excimer laser irradiation at energy densities exceeding 1.75 J/cm2, giving rise to free Si atoms and SiO2, however with complete disappearance of Al atoms. Model photochemical reactions are proposed to explain such transformations.

Langmuir-Blodgett films of random copolymers of fluoroalkyl(meth)acrylate and methacrylic acid: Fabrication and X-ray diffraction study

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

Safronov, V.; Feigin, L.A.; Budovskaya, L.D.

1994-12-31

Langmuir-Blodgett films of amphiphilic fluorinated copolymers were fabricated and studied by X-ray diffraction. Although these films show poor interlayer periodicity, they possess a uniform thickness even in the case of very thin films of one bilayer (22 {angstrom}). This feature was used to obtain complex LB structures (superlattices) with alteration of copolymer and fatty acid bilayers. X-ray diffraction data proved the regular periodical organization of these structures and allowed to calculate electron density distribution across the superlattices.

X-Ray Standing Waves on Surfaces

DTIC Science & Technology

1993-01-01

dependent distributional changes of iodine on Pt 6.3 X-ray standing wave study of a Langmuir - Blodgett multilayer film 7. Conclusions 8. Acknowledgments...4B. 6.3 X-ray standing wave study of a Langmuir - Blodgett multilayer film As mentioned previously the total external reflection condition occurs...for a Zn atom layer embedded in the top arachidate bilayer of a Langmuir - Blodgett (LB) multilayer film which was deposited on the surface of a gold

Structural characterization of porous low-k thin films prepared by different techniques using x-ray porosimetry

NASA Astrophysics Data System (ADS)

Lee, Hae-Jeong; Soles, Christopher L.; Liu, Da-Wei; Bauer, Barry J.; Lin, Eric K.; Wu, Wen-li; Grill, Alfred

2004-03-01

Three different types of porous low-k dielectric films, with similar dielectric constants, are characterized using x-ray porosimetry (XRP). XRP is used to extract critical structural information, such as the average density, wall density, porosity, and pore size distribution. The materials include a plasma-enhanced-chemical-vapor-deposited carbon-doped oxide film composed of Si, C, O, and H (SiCOH) and two spin cast silsesquioxane type films—methylsilsesquioxane with a polymeric porogen (porous MSQ) and hydrogensilsesquioxane with a high boiling point solvent (porous HSQ). The porous SiCOH film displays the smallest pore sizes, while porous HSQ film has both the highest density wall material and porosity. The porous MSQ film exhibits a broad range of pores with the largest average pore size. We demonstrate that the average pore size obtained by the well-established method of neutron scattering and x-ray reflectivity is in good agreement with the XRP results.

Roles of Thin Film Stress in Making Extremely Lightweight X-Ray Optics

NASA Technical Reports Server (NTRS)

Zhang, William W.

2010-01-01

X-ray optics typically must be coated with one of the noble metals, gold, platinum, or iridium, to enhance their photon collection area. In general, iridium is preferred to the other two because it generates the highest X-ray reflectivity in the I to 10 keV band. Unfortunately, iridium films typically have also the highest stress that can severely degrade the optical figure of the mirror substrate, resulting in a poorer image quality. In this paper we will report our work in understanding this stress and our method to counterbalance it. In particular we will also report on potential ways of using this stress to improve the substrate's optical figure, turning a bug into a desirable feature. This work is done in the context of developing an enabling technology for the International X-ray Observatory which is a collaborative mission of NASA, ESA, and JAXA, and expected to be launched into an L2 orbit in 2021.

Grazing incidence X-ray absorption characterization of amorphous Zn-Sn-O thin film

NASA Astrophysics Data System (ADS)

Moffitt, S. L.; Ma, Q.; Buchholz, D. B.; Chang, R. P. H.; Bedzyk, M. J.; Mason, T. O.

2016-05-01

We report a surface structure study of an amorphous Zn-Sn-O (a-ZTO) transparent conducting film using the grazing incidence X-ray absorption spectroscopy technique. By setting the measuring angles far below the critical angle at which the total external reflection occurs, the details of the surface structure of a film or bulk can be successfully accessed. The results show that unlike in the film where Zn is severely under coordinated (N < 4), it is fully coordinated (N = 4) near the surface while the coordination number around Sn is slightly smaller near the surface than in the film. Despite a 30% Zn doping, the local structure in the film is rutile-like.

Magnetic and chemical nonuniformity in Ga{sub 1-x}Mn{sub x}As films as probed by polarized neutron and x-ray reflectometry

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

Kirby, B. J.; Borchers, J. A.; Rhyne, J. J.

We have used complementary neutron and x-ray reflectivity techniques to examine the depth profiles of a series of as-grown and annealed Ga{sub 1-x}Mn{sub x}As thin films. A magnetization gradient is observed for two as-grown films and originates from a nonuniformity of Mn at interstitial sites, and not from local variations in Mn at Ga sites. Furthermore, we see that the depth-dependent magnetization can vary drastically among as-grown Ga{sub 1-x}Mn{sub x}As films despite being deposited under seemingly similar conditions. These results imply that the depth profile of interstitial Mn is dependent not only on annealing, but is also extremely sensitive tomore » initial growth conditions. We observe that annealing improves the magnetization by producing a surface layer that is rich in Mn and O, indicating that the interstitial Mn migrates to the surface. Finally, we expand upon our previous neutron reflectivity study of Ga{sub 1-x}Mn{sub x}As, by showing how the depth profile of the chemical composition at the surface and through the film thickness is directly responsible for the complex magnetization profiles observed in both as-grown and annealed films.« less

Note: Soft X-ray transmission polarizer based on ferromagnetic thin films

NASA Astrophysics Data System (ADS)

Müller, L.; Hartmann, G.; Schleitzer, S.; Berntsen, M. H.; Walther, M.; Rysov, R.; Roseker, W.; Scholz, F.; Seltmann, J.; Glaser, L.; Viefhaus, J.; Mertens, K.; Bagschik, K.; Frömter, R.; De Fanis, A.; Shevchuk, I.; Medjanik, K.; Öhrwall, G.; Oepen, H. P.; Martins, M.; Meyer, M.; Grübel, G.

2018-03-01

A transmission polarizer for producing elliptically polarized soft X-ray radiation from linearly polarized light is presented. The setup is intended for use at synchrotron and free-electron laser beamlines that do not directly offer circularly polarized light for, e.g., X-ray magnetic circular dichroism (XMCD) measurements or holographic imaging. Here, we investigate the degree of ellipticity upon transmission of linearly polarized radiation through a cobalt thin film. The experiment was performed at a photon energy resonant to the Co L3-edge, i.e., 778 eV, and the polarization of the transmitted radiation was determined using a polarization analyzer that measures the directional dependence of photo electrons emitted from a gas target. Elliptically polarized radiation can be created at any absorption edge showing the XMCD effect by using the respective magnetic element.

Advances in photographic X-ray imaging for solar astronomy

NASA Technical Reports Server (NTRS)

Moses, J. Daniel; Schueller, R.; Waljeski, K.; Davis, John M.

1989-01-01

The technique of obtaining quantitative data from high resolution soft X-ray photographic images produced by grazing incidence optics was successfully developed to a high degree during the Solar Research Sounding Rocket Program and the S-054 X-Ray Spectrographic Telescope Experiment Program on Skylab. Continued use of soft X-ray photographic imaging in sounding rocket flights of the High Resolution Solar Soft X-Ray Imaging Payload has provided opportunities to further develop these techniques. The developments discussed include: (1) The calibration and use of an inexpensive, commercially available microprocessor controlled drum type film processor for photometric film development; (2) The use of Kodak Technical Pan 2415 film and Kodak SO-253 High Speed Holographic film for improved resolution; and (3) The application of a technique described by Cook, Ewing, and Sutton for determining the film characteristics curves from density histograms of the flight film. Although the superior sensitivity, noise level, and linearity of microchannel plate and CCD detectors attracts the development efforts of many groups working in soft X-ray imaging, the high spatial resolution and dynamic range as well as the reliability and ease of application of photographic media assures the continued use of these techniques in solar X-ray astronomy observations.

Structure of disordered gold-polymer thin films using small angle x-ray scattering

NASA Astrophysics Data System (ADS)

Teixeira, F. S.; Salvadori, M. C.; Cattani, M.; Brown, I. G.

2010-11-01

We have investigated the structure of disordered gold-polymer thin films using small angle x-ray scattering and compared the results with the predictions of a theoretical model based on two approaches—a structure form factor approach and the generalized Porod law. The films are formed of polymer-embedded gold nanoclusters and were fabricated by very low energy gold ion implantation into polymethylmethacrylate (PMMA). The composite films span (with dose variation) the transition from electrically insulating to electrically conducting regimes, a range of interest fundamentally and technologically. We find excellent agreement with theory and show that the PMMA-Au films have monodispersive or polydispersive characteristics depending on the implanted ion dose.

X-ray line profile analysis of BaTiO3 thin film prepared by sol-gel deposition

NASA Astrophysics Data System (ADS)

Ooi, Zeen Vee; Saif, Ala'eddin A.; Wahab, Yufridin; Jamal, Zul Azhar Zahid

2017-04-01

Barium titanate (BaTiO3) thin film was prepared using sol-gel method and spun-coated on SiO2/Si substrate. The phase and crystallinity of the synthesized film were identified using X-ray diffractometer (XRD), which scanned at the range of 20° to 60°. The phase and lattice parameters of the fabricated film were extracted from the recorded XRD patterns using lattice geometry equations. The crystallite size and lattice strain were determined using X-ray line profile analysis (XLPA) with various approaches. The Scherrer equation was applied to the perovskite peaks of the film to explore the size contribution on the peak broadening. Meanwhile, the Williamson-Hall and size-strain plot (SSP) methods were used to review two main independent contributions, i.e. crystallite sizes and lattice strain, on the X-ray line broadening. From the analysis, it is found that Scherrer method gives smallest crystallite size value by ignoring the strain-induced broadening effect. On the other hand, Williamson-Hall and SSP graphs revealed the existence of the lattice strain within the film, which contributes to the broadening in the Bragg peak. The results that analyzed via both techniques show a linear trend with all data points fitted. However, result obtained from SSP method gives better settlement due to the best fit of the data.

X-ray analyses of thermally grown and reactively sputtered tantalum oxide films on NiTi alloy

NASA Astrophysics Data System (ADS)

McNamara, Karrina; Tofail, Syed A. M.; Conroy, Derek; Butler, James; Gandhi, Abbasi A.; Redington, Wynette

2012-08-01

Sputter deposition of tantalum (Ta) on the surface of NiTi alloy is expected to improve the alloy's corrosion resistance and biocompatibility. Tantalum is a well-known biomaterial which is not affected by body fluids and is not irritating to human tissue. Here we compare the oxidation chemistry crystal structure evolution of tantalum oxide films grown on NiTi by reactive O2 sputtering and by thermal oxidation of sputter deposited Ta films. The effect of sputtering parameters and post-sputtering treatments on the morphology, oxidation state and crystal structure of the tantalum oxide layer have been investigated by field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The study has found that it may be better to avoid oxidation at and above 600 °C. The study establishes that reactive sputtering in presence of low oxygen mixture yields thicker film with better control of the film quality except that the surface oxidation state of Ta is slightly lower.

Characterization of thermally evaporated lead iodide films aimed for the detection of X-rays

NASA Astrophysics Data System (ADS)

Caldeira Filho, A. M.; Mulato, M.

2011-04-01

Some semiconductor materials such as lead iodide (PbI2) have applications in the detection of ionizing radiation at room temperature using the direct detection method. In this work we investigate lead iodide films deposited by thermal evaporation. The morphology, structure, and electric properties were investigated as a function of deposition height, i.e. the distance between evaporation-boat and substrates. The results show a morphology of vertical leaves and X-ray diffraction shows just one preferential orientation along the direction 110. Energy dispersive spectroscopy reveals that the films are not stoichiometric, with excess iodine atoms. Electrical resistivity of about 108 Ω cm was measured. This is smaller than for the bulk due to structural defects. The values of activation energy for electric transport increase from 0.52 up to 1.1 eV with decreasing deposition height, what indicates that the best film is the one deposited at the shortest distance. Exposure under X-ray mammographic energy shows a linear behavior up to 500 mR. No variation in sensibility was observed between 22 and 30 kVp.

Mechanical design of multiple zone plates precision alignment apparatus for hard X-ray focusing in twenty-nanometer scale

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

Shu, Deming; Liu, Jie; Gleber, Sophie C.

An enhanced mechanical design of multiple zone plates precision alignment apparatus for hard x-ray focusing in a twenty-nanometer scale is provided. The precision alignment apparatus includes a zone plate alignment base frame; a plurality of zone plates; and a plurality of zone plate holders, each said zone plate holder for mounting and aligning a respective zone plate for hard x-ray focusing. At least one respective positioning stage drives and positions each respective zone plate holder. Each respective positioning stage is mounted on the zone plate alignment base frame. A respective linkage component connects each respective positioning stage and the respectivemore » zone plate holder. The zone plate alignment base frame, each zone plate holder and each linkage component is formed of a selected material for providing thermal expansion stability and positioning stability for the precision alignment apparatus.« less

Multilayer films with sharp, stable interfaces for use in EUV and soft X-ray application

DOEpatents

Barbee, Jr., Troy W.; Bajt, Sasa

2002-01-01

The reflectivity and thermal stability of Mo/Si (molybdenum/silicon) multilayer films, used in soft x-ray and extreme ultraviolet region, is enhanced by deposition of a thin layer of boron carbide (e.g., B.sub.4 C) between alternating layers of Mo and Si. The invention is useful for reflective coatings for soft X-ray and extreme ultraviolet optics, multilayer for masks, coatings for other wavelengths and multilayers for masks that are more thermally stable than pure Mo/Si multilayers

Prototyping iridium coated mirrors for x-ray astronomy

NASA Astrophysics Data System (ADS)

Döhring, Thorsten; Probst, Anne-Catherine; Stollenwerk, Manfred; Emmerich, Florian; Stehlíková, Veronika; Inneman, Adolf

2017-05-01

X-ray astronomy uses space-based telescopes to overcome the disturbing absorption of the Earth's atmosphere. The telescope mirrors are operating at grazing incidence angles and are coated with thin metal films of high-Z materials to get sufficient reflectivity for the high-energy radiation to be observed. In addition the optical payload needs to be light-weighted for launcher mass constrains. Within the project JEUMICO, an acronym for "Joint European Mirror Competence", the Aschaffenburg University of Applied Sciences and the Czech Technical University in Prague started a collaboration to develop mirrors for X-ray telescopes. The X-ray telescopes currently developed within this Bavarian- Czech project are of Lobster eye type optical design. Corresponding mirror segments use substrates of flat silicon wafers which are coated with thin iridium films, as this material is promising high reflectivity in the X-ray range of interest. The deposition of the iridium films is based on a magnetron sputtering process. Sputtering with different parameters, especially by variation of the argon gas pressure, leads to iridium films with different properties. In addition to investigations of the uncoated mirror substrates the achieved surface roughness has been studied. Occasional delamination of the iridium films due to high stress levels is prevented by chromium sublayers. Thereby the sputtering parameters are optimized in the context of the expected reflectivity of the coated X-ray mirrors. In near future measurements of the assembled mirror modules optical performances are planned at an X-ray test facility.

A comparison of Kodak Ultraspeed and Ektaspeed Plus dental X-ray films for use in endodontics.

PubMed

Moule, A J; Wong, A; Monsour, P A; Basford, K E

2001-06-01

The advantage of using a faster film for length determination in endodontic therapy is obvious. However, for such a film to be generally accepted, it must demonstrate comparable diagnostic quality to traditionally used films. The comparative accuracy of canal length determination of Ultraspeed and Ektaspeed Plus dental X-ray films was assessed in maxillary first and second molars; for different canals, for different teeth, for different exposures, and for different examiners (five general dentists and three endodontic specialists). In general, there were no significant differences between films, among examiners, or any interaction between films and exposures. That is, an assessor's ability to estimate lengths was not significantly influenced by the film type or by exposure used. There was a wide divergence in the individual assessor's ability to estimate lengths. Specialists estimated lengths more accurately than general practitioners and estimated lengths more accurately with Ektaspeed Plus film. Length determination in distobuccal and mesiobuccal canals was more accurate than in palatal canals. Most palatal canals were underestimated in length by more than 1mm. The use of file sizes larger in number than size 15 is recommended in these canals. For length determination, Ektaspeed Plus dental X-ray film is as effective as Ultraspeed film. Given the acceptable quality and accuracy of Ektaspeed Plus film, there seems to be no clinical reason to subject patients to greater radiation by using a slower film during endodontic therapy.

Characterization of crystallographic properties of thin films using X-ray diffraction

NASA Astrophysics Data System (ADS)

Zoo, Yeongseok

2007-12-01

Silver (Ag) has been recognized as one of promising candidates in Ultra-Large Scale Integrated (ULSI) applications in that it has the lowest bulk electrical resistivity of all pure metals and higher electromigration resistance than other interconnect materials. However, low thermal stability on Silicon Dioxide (Si02) at high temperatures (e.g., agglomeration) is considered a drawback for the Ag metallization scheme. Moreover, if a thin film is attached on a substrate, its properties may differ significantly from that of the bulk, since the properties of thin films can be significantly affected by the substrate. In this study, the Coefficient of Thermal Expansion (CTE) and texture evolution of Ag thin films on different substrates were characterized using various analytical techniques. The experimental results showed that the CTE of the Ag thin film was significantly affected by underlying substrate and the surface roughness of substrate. To investigate the alloying effect for Ag meatallization, small amounts of Copper (Cu) were added and characterized using theta-2theta X-ray Diffraction (XRD) scan and pole figure analysis. These XRD techniques are useful for investigating the primary texture of a metal film, (111) in this study, which (111) is the notation of a specific plane in the orthogonal coordinate system. They revealed that the (111) textures of Ag and Ag(Cu) thin films were enhanced with increasing temperature. Comparison of texture profiles between Ag and Ag(Cu) thin films showed that Cu additions enhanced (111) texture in Ag thin films. Accordingly, the texture enhancement in Ag thin films by Cu addition was discussed. Strained Silicon-On-Insulator (SSOI) is being considered as a potential substrate for Complementary Metal-Oxide-Semiconductor (CMOS) technology since the induced strain results in a significant improvement in device performance. High resolution X-ray diffraction (XRD) techniques were used to characterize the perpendicular and parallel

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

NASA Astrophysics Data System (ADS)

Marton, Zsolt; Miller, Stuart R.; Brecher, Charles; Kenesei, Peter; Moore, Matthew D.; Woods, Russell; Almer, Jonathan D.; Miceli, Antonino; Nagarkar, Vivek V.

2015-09-01

We have developed microstructured Lu2O3:Eu scintillator films that provide spatial resolution on the order of micrometers for hard X-ray imaging. In addition to their outstanding resolution, Lu2O3:Eu films also exhibits both high absorption efficiency for 20 to 100 keV X-rays, and bright 610 nm emission whose intensity rivals that of the brightest known scintillators. At present, high spatial resolution of such a magnitude is achieved using ultra-thin scintillators measuring only about 1 to 5 μm in thickness, which limits absorption efficiency to ~3% for 12 keV X-rays and less than 0.1% for 20 to 100 keV X-rays; this results in excessive measurement time and exposure to the specimen. But the absorption efficiency of Lu2O3:Eu (99.9% @12 keV and 30% @ 70 keV) is much greater, significantly decreasing measurement time and radiation exposure. Our Lu2O3:Eu scintillator material, fabricated by our electron-beam physical vapor deposition (EB-PVD) process, combines superior density of 9.5 g/cm3, a microcolumnar structure for higher spatial resolution, and a bright emission (48000 photons/MeV) whose wavelength is an ideal match for the underlying CCD detector array. We grew thin films of this material on a variety of matching substrates, measuring some 5-10μm in thickness and covering areas up to 1 x 1 cm2, which can be a suitable basis for microtomography, digital radiography as well as CT and hard X-ray Micro-Tomography (XMT). The microstructure and optical transparency of such screens was optimized, and their imaging performance was evaluated in the Argonne National Laboratory's Advanced Photon Source. Spatial resolution and efficiency were also characterized.

Positron annihilation and X-ray diffraction studies on tin oxide thin films

NASA Astrophysics Data System (ADS)

Prabakar, K.; Abhaya, S.; Krishnan, R.; Kalavathi, S.; Dash, S.; Jayapandian, J.; Amarendra, G.

2009-04-01

Positron annihilation spectroscopy along with glancing incidence X-ray diffraction have been used to investigate tin oxide thin films grown on Si by pulsed laser deposition. The films were prepared at room temperature and at 670 K under oxygen partial pressure. As-grown samples are amorphous and are found to contain large concentration of open volume sites (vacancy defects). Post-deposition annealing of as-grown samples at 970 K is found to drastically reduce the number of open volume sites and the film becomes crystalline. However, film grown under elevated temperature and under partial pressure of oxygen is found to exhibit a lower S-parameter, indicating lower defect concentration. Based on the analysis of experimental positron annihilation results, the defect-sensitive S-parameter and the overlayer thickness of tin oxide thin films are deduced. S- W correlation plots exhibit distinct positron trapping defect states in three samples.

Direct X-ray photoconversion in flexible organic thin film devices operated below 1 V

PubMed Central

Basiricò, Laura; Ciavatti, Andrea; Cramer, Tobias; Cosseddu, Piero; Bonfiglio, Annalisa; Fraboni, Beatrice

2016-01-01

The application of organic electronic materials for the detection of ionizing radiations is very appealing thanks to their mechanical flexibility, low-cost and simple processing in comparison to their inorganic counterpart. In this work we investigate the direct X-ray photoconversion process in organic thin film photoconductors. The devices are realized by drop casting solution-processed bis-(triisopropylsilylethynyl)pentacene (TIPS-pentacene) onto flexible plastic substrates patterned with metal electrodes; they exhibit a strong sensitivity to X-rays despite the low X-ray photon absorption typical of low-Z organic materials. We propose a model, based on the accumulation of photogenerated charges and photoconductive gain, able to describe the magnitude as well as the dynamics of the X-ray-induced photocurrent. This finding allows us to fabricate and test a flexible 2 × 2 pixelated X-ray detector operating at 0.2 V, with gain and sensitivity up to 4.7 × 104 and 77,000 nC mGy−1 cm−3, respectively. PMID:27708274

Two-photon x-ray diffraction

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

Stohr, J.

The interference pattern of a circular photon source has long been used to define the optical diffraction limit. Here we show the breakdown of conventional x-ray diffraction theory for the fundamental case of a “source”, consisting of a back-illuminated thin film in a circular aperture. When the conventional spontaneous x-ray scattering by atoms in the film is replaced at high incident intensity by stimulated resonant scattering, the film becomes the source of cloned photon twins and the diffraction pattern becomes self-focused beyond the diffraction limit. Furthermore, the case of cloned photon pairs is compared to and distinguished from entangled photonmore » pairs or biphotons.« less

Two-photon x-ray diffraction

DOE PAGES

Stohr, J.

2017-01-11

The interference pattern of a circular photon source has long been used to define the optical diffraction limit. Here we show the breakdown of conventional x-ray diffraction theory for the fundamental case of a “source”, consisting of a back-illuminated thin film in a circular aperture. When the conventional spontaneous x-ray scattering by atoms in the film is replaced at high incident intensity by stimulated resonant scattering, the film becomes the source of cloned photon twins and the diffraction pattern becomes self-focused beyond the diffraction limit. Furthermore, the case of cloned photon pairs is compared to and distinguished from entangled photonmore » pairs or biphotons.« less

Characterisation of LSO:Tb scintillator films for high resolution X-ray imaging applications

NASA Astrophysics Data System (ADS)

Cecilia, A.; Rack, A.; Douissard, P.-A.; Martin, T.; Dos Santos Rolo, T.; Vagovič, P.; Pelliccia, D.; Couchaud, M.; Dupré, K.; Baumbach, T.

2011-05-01

Within the framework of an FP6 project (SCINTAX)1The Project SCINTAX is funded by the European Community (STRP 033 427), . we developed a new thin film single crystal scintillator for high resolution X-ray imaging based on a layer of modified LSO (Lu2SiO5) grown by liquid phase epitaxy (LPE) on a dedicated substrate. In this work we present the characterisation of the scintillating LSO films in terms of optical and scintillation properties as well as spatial resolution performances. The obtained results are discussed and compared with the performances of the thin scintillating films commonly used in synchrotron-based micro-imaging applications.

Imaging Local Polarization in Ferroelectric Thin Films by Coherent X-Ray Bragg Projection Ptychography

NASA Astrophysics Data System (ADS)

Hruszkewycz, S. O.; Highland, M. J.; Holt, M. V.; Kim, Dongjin; Folkman, C. M.; Thompson, Carol; Tripathi, A.; Stephenson, G. B.; Hong, Seungbum; Fuoss, P. H.

2013-04-01

We used x-ray Bragg projection ptychography (BPP) to map spatial variations of ferroelectric polarization in thin film PbTiO3, which exhibited a striped nanoscale domain pattern on a high-miscut (001) SrTiO3 substrate. By converting the reconstructed BPP phase image to picometer-scale ionic displacements in the polar unit cell, a quantitative polarization map was made that was consistent with other characterization. The spatial resolution of 5.7 nm demonstrated here establishes BPP as an important tool for nanoscale ferroelectric domain imaging, especially in complex environments accessible with hard x rays.

Composition measurement of epitaxial Sc x Ga1-x N films

NASA Astrophysics Data System (ADS)

Tsui, H. C. L.; Goff, L. E.; Barradas, N. P.; Alves, E.; Pereira, S.; Palgrave, R. G.; Davies, R. J.; Beere, H. E.; Farrer, I.; Ritchie, D. A.; Moram, M. A.

2016-06-01

Four different methods for measuring the compositions of epitaxial Sc x Ga1-x N films were assessed and compared to determine which was the most reliable and accurate. The compositions of epitaxial Sc x Ga1-x N films with 0 ≤ x ≤ 0.26 were measured directly using Rutherford backscattering (RBS) and x-ray photoelectron spectroscopy (XPS), and indirectly using c lattice parameter measurements from x-ray diffraction and c/a ratio measurements from electron diffraction patterns. RBS measurements were taken as a standard reference. XPS was found to underestimate the Sc content, whereas c lattice parameter and c/a ratio were not reliable for composition determination due to the unknown degree of strain relaxation in the film. However, the Sc flux used during growth was found to relate linearly with x and could be used to estimate the Sc content.

X-ray probe of GaN thin films grown on InGaN compliant substrates

NASA Astrophysics Data System (ADS)

Xu, Xiaoqing; Li, Yang; Liu, Jianming; Wei, Hongyuan; Liu, Xianglin; Yang, Shaoyan; Wang, Zhanguo; Wang, Huanhua

2013-04-01

GaN thin films grown on InGaN compliant substrates were characterized by several X-ray technologies: X-ray reciprocal space mapping (RSM), grazing incidence X-ray diffraction (GIXRD), and X-ray photoemission spectrum (XPS). Narrow Lorentz broadening and stress free state were observed for GaN grown on InGaN compliant substrate, while mosaic structure and large tensile stress were observed at the presence of residual indium atoms. RSM disclosed the mosaicity, and the GIXRD was conducted to investigate the depth dependences of crystal quality and strain states. XPS depth profile of indium contents indicated that residual indium atoms deteriorated the crystal quality of GaN not only by producing lattice mismatch at the interface of InGaN and GaN but also by diffusing into GaN overlayers. Accordingly, two solutions were proposed to improve the efficiency of self-patterned lateral epitaxial overgrowth method. This research goes a further step in resolving the urgent substrate problem in GaN fabrication.

X-Ray Photoelectron Spectroscopy of Stabilized Zirconia Films with Embedded Au Nanoparticles Formed under Irradiation with Gold Ions

NASA Astrophysics Data System (ADS)

Zubkov, S. Yu.; Antonov, I. N.; Gorshkov, O. N.; Kasatkin, A. P.; Kryukov, R. N.; Nikolichev, D. E.; Pavlov, D. A.; Shenina, M. E.

2018-03-01

Nanosized films of stabilized zirconia with Au nanoparticles formed by implanting Au ions are studied by X-ray photoelectron spectroscopy and transmission electron microscopy. The effect of irradiation of films with Au ions and postimplantation annealing on the distribution of chemical elements and zirconium- containing ZrO x compounds over the depth of the films is studied. Based on the data on the dimensional shift of the Au 4 f photoelectron line, the average value of the nanoparticle size is determined.

The characterization of Cr secondary oxide phases in ZnO films studied by X-ray spectroscopy and photoemission spectroscopy

NASA Astrophysics Data System (ADS)

Chiou, J. W.; Chang, S. Y.; Huang, W. H.; Chen, Y. T.; Hsu, C. W.; Hu, Y. M.; Chen, J. M.; Chen, C.-H.; Kumar, K.; Guo, J.-H.

2011-03-01

X-ray absorption near-edge structure (XANES), X-ray emission spectroscopy (XES), and X-ray photoemission spectroscopy (XPS) were used to characterize the Cr secondary oxide phases in ZnO films that had been prepared using a co-sputtering method. Analysis of the Cr L3,2-edge XANES spectra reveals that the intensity of white-line features decreases subtly as the sputtering power increases, indicating that the occupation of Cr 3 d orbitals increases with Cr concentration in (Zn, Cr)O films. The O K-edge spectra show that the intensity of XANES features of (Zn, Cr)O films is lower than those of ZnO film, suggesting enhanced occupation of O 2 p-derived states through O 2 p-Cr 3 d hybridization. The XES and XPS spectra indicate that the line shapes in the valence band of (Zn, Cr)O films are quite different from those of ZnO and that the Cr 2O 3 phase dominates the spinel structure of (Zn, Cr)O films increasingly as the Cr sputtering power is increased. Over all results suggest that the non-ferromagnetic behavior of (Zn, Cr)O films can be attributed to the dominant presence of Cr 2O 3, whereas the bulk comprise phase segregations of Cr 2O 3 and/or ZnCr 2O 4, which results them the most stable TM-doped ZnO material against etching.

Elemental depth profiling in transparent conducting oxide thin film by X-ray reflectivity and grazing incidence X-ray fluorescence combined analysis

NASA Astrophysics Data System (ADS)

Rotella, H.; Caby, B.; Ménesguen, Y.; Mazel, Y.; Valla, A.; Ingerle, D.; Detlefs, B.; Lépy, M.-C.; Novikova, A.; Rodriguez, G.; Streli, C.; Nolot, E.

2017-09-01

The optical and electrical properties of transparent conducting oxide (TCO) thin films are strongly linked with the structural and chemical properties such as elemental depth profile. In R&D environments, the development of non-destructive characterization techniques to probe the composition over the depth of deposited films is thus necessary. The combination of Grazing-Incidence X-ray Fluorescence (GIXRF) and X-ray reflectometry (XRR) is emerging as a fab-compatible solution for the measurement of thickness, density and elemental profile in complex stacks. Based on the same formalism, both techniques can be implemented on the same experimental set-up and the analysis can be combined in a single software in order to refine the sample model. While XRR is sensitive to the electronic density profile, GIXRF is sensitive to the atomic density (i. e. the elemental depth profile). The combination of both techniques allows to get simultaneous information about structural properties (thickness and roughness) as well as the chemical properties. In this study, we performed a XRR-GIXRF combined analysis on indium-free TCO thin films (Ga doped ZnO compound) in order to correlate the optical properties of the films with the elemental distribution of Ga dopant over the thickness. The variation of optical properties due to annealing process were probed by spectroscopic ellipsometry measurements. We studied the evolution of atomic profiles before and after annealing process. We show that the blue shift of the band gap in the optical absorption edge is linked to a homogenization of the atomic profiles of Ga and Zn over the layer after the annealing. This work demonstrates that the combination of the techniques gives insight into the material composition and makes the XRR-GIXRF combined analysis a promising technique for elemental depth profiling.

Local Plasticity of Al Thin Films as Revealed by X-Ray Microdiffraction

NASA Astrophysics Data System (ADS)

Spolenak, R.; Brown, W. L.; Tamura, N.; MacDowell, A. A.; Celestre, R. S.; Padmore, H. A.; Valek, B.; Bravman, J. C.; Marieb, T.; Fujimoto, H.; Batterman, B. W.; Patel, J. R.

2003-03-01

Grain-to-grain interactions dominate the plasticity of Al thin films and establish effective length scales smaller than the grain size. We have measured large strain distributions and their changes under plastic strain in 1.5-μm-thick Al0.5%Cu films using a 0.8-μm-diameter white x-ray probe at the Advanced Light Source. Strain distributions arise not only from the distribution of grain sizes and orientation, but also from the differences in grain shape and from stress environment. Multiple active glide plane domains have been found within single grains. Large grains behave like multiple smaller grains even before a dislocation substructure can evolve.

Automatic SMT Inspection With -X-Ray Vision

NASA Astrophysics Data System (ADS)

Kuntz, Robert A.; Steinmetz, Peter D.

1988-02-01

X-ray is used in many different ways and in a broad variety of applications with today's world. One of the most obvious uses is in the medically related applications. Although less obvious, x-ray is used within industry as well. Inspection of metal castings, pipe-line welds, equipment structures and personal security are just a few. Historically, both medical and industrial x-ray have been dependent on film exposure, development and reading to capture and present the projected image. This process however is labor intensive, time consuming and costly. Correct exposure time and proper view orientation are in question until the film is developed and examined. In many cases, this trial and error causes retakes with the accompanying expense and delays. Recently, due to advances in x-ray tube technology, tubes with microfocus construction have become available. These tubes operate at high enough flux density such that when combined with x-ray to visible light converters, real-time imaging is possible.

LPE grown LSO:Tb scintillator films for high-resolution X-ray imaging applications at synchrotron light sources

NASA Astrophysics Data System (ADS)

Cecilia, A.; Rack, A.; Douissard, P.-A.; Martin, T.; Dos Santos Rolo, T.; Vagovič, P.; Hamann, E.; van de Kamp, T.; Riedel, A.; Fiederle, M.; Baumbach, T.

2011-08-01

Within the project ScinTAX of the 6th framework program (FP6) of the European Commission (SCINTAX—STRP 033 427) we have developed a new thin single crystal scintillator for high-resolution X-ray imaging. The scintillator is based on a Tb-doped Lu2SiO5 (LSO) film epitaxially grown on an adapted substrate. The high density, effective atomic number and light yield of the scintillating LSO significantly improves the efficiency of the X-ray imaging detectors currently used in synchrotron micro-imaging applications. In this work we present the characterization of the scintillating LSO films in terms of their spatial resolution performance and we provide two examples of high spatial and high temporal resolution applications.

High spatial resolution grain orientation and strain mapping in thin films using polychromatic submicron x-ray diffraction

NASA Astrophysics Data System (ADS)

Tamura, N.; MacDowell, A. A.; Celestre, R. S.; Padmore, H. A.; Valek, B.; Bravman, J. C.; Spolenak, R.; Brown, W. L.; Marieb, T.; Fujimoto, H.; Batterman, B. W.; Patel, J. R.

2002-05-01

The availability of high brilliance synchrotron sources, coupled with recent progress in achromatic focusing optics and large area two-dimensional detector technology, has allowed us to develop an x-ray synchrotron technique that is capable of mapping orientation and strain/stress in polycrystalline thin films with submicron spatial resolution. To demonstrate the capabilities of this instrument, we have employed it to study the microstructure of aluminum thin film structures at the granular and subgranular levels. Due to the relatively low absorption of x-rays in materials, this technique can be used to study passivated samples, an important advantage over most electron probes given the very different mechanical behavior of buried and unpassivated materials.

Adjustable Grazing-Incidence X-Ray Optics

NASA Technical Reports Server (NTRS)

O'Dell, Stephen L.; Reid, Paul B.

2015-01-01

With its unique subarcsecond imaging performance, NASA's Chandra X-ray Observatory illustrates the importance of fine angular resolution for x-ray astronomy. Indeed, the future of x-ray astronomy relies upon x-ray telescopes with comparable angular resolution but larger aperture areas. Combined with the special requirements of nested grazing-incidence optics, mass, and envelope constraints of space-borne telescopes render such advances technologically and programmatically challenging. The goal of this technology research is to enable the cost-effective fabrication of large-area, lightweight grazing-incidence x-ray optics with subarcsecond resolution. Toward this end, the project is developing active x-ray optics using slumped-glass mirrors with thin-film piezoelectric arrays for correction of intrinsic or mount-induced distortions.

Recent developments of x-ray lithography in Canada

NASA Astrophysics Data System (ADS)

Chaker, Mohamed; Boily, Stephane; Ginovker, A.; Jean, Alain; Kieffer, Jean-Claude; Mercier, P. P.; Pepin, Henri; Leung, Pak; Currie, John F.; Lafontaine, Hugues

1991-08-01

An overview of current activities in Canada is reported, including x-ray lithography studies based on laser plasma sources and x-ray mask development. In particular, the application of laser plasma sources for x-ray lithography is discussed, taking into account the industrial requirement and the present state of laser technology. The authors describe the development of silicon carbide membranes for x-ray lithography application. SiC films were prepared using either a 100 kHz plasma-enhanced chemical vapor deposition (PECVD) system or a laser ablation technique. These membranes have a relatively large diameter (> 1 in.) and a high optical transparency (> 50%). Experimental studies on stresses in tungsten films deposited with triode sputtering are reported.

Compound formation and superconductivity in Au-Si: X-ray absorption measurements on ion-beam-mixed Au-Si films

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

Jeon, Y.; Jisrawi, N.; Liang, G.

Multilayered Au-Si thin films have been deposited with the net compositions ''Au/sub 1-//sub x/Si/sub x/,'' x = 0.29, 0.5, and 0.8. After ion-beam mixing these films exhibited superconductivity in the 0.3--1.2 K range despite the nonsuperconducting character of both Au and Si. Near-edge x-ray absorption spectroscopy (XAS) measurements on the Au L/sub 3/ edge in these films indicate that metastable Au-Si compound formation occurs in these ion-mixed materials. Specifically, the XAS measurements indicate changes in Au 5d-orbital occupancy and changes in the local Au structural environment which are both consistent with local compound formation.

Electronic and magnetic properties of manganite thin films with different compositions and its correlation with transport properties: An X-ray resonant magnetic scattering study

DOE PAGES

Singh, Surendra; Freeland, J. W.; Fitzsimmons, M. R.; ...

2014-12-08

Here, we present x-ray resonant magnetic dichroism and x-ray resonant magnetic scattering measurements of the temperature dependence of magnetism in Pr-doped La-Ca-Mn-O films grown on (110) NdGaO3 substrates. We observed thermal hysteresis of the ferromagnetism in one film that also showed large thermal hysteresis of ~18K in transport measurements. While in a second film of a different nominal chemistry, which showed very small thermal hysteresis ~3K in transport measurements, no thermal hysteresis of the ferromagnetism was observed. As a result, these macroscopic properties are correlated with evolution of surface magnetization across metal insulator transition for these films as observed bymore » soft x-ray resonant magnetic scattering measurements.« less

X-ray crystallography

NASA Technical Reports Server (NTRS)

2001-01-01

X-rays diffracted from a well-ordered protein crystal create sharp patterns of scattered light on film. A computer can use these patterns to generate a model of a protein molecule. To analyze the selected crystal, an X-ray crystallographer shines X-rays through the crystal. Unlike a single dental X-ray, which produces a shadow image of a tooth, these X-rays have to be taken many times from different angles to produce a pattern from the scattered light, a map of the intensity of the X-rays after they diffract through the crystal. The X-rays bounce off the electron clouds that form the outer structure of each atom. A flawed crystal will yield a blurry pattern; a well-ordered protein crystal yields a series of sharp diffraction patterns. From these patterns, researchers build an electron density map. With powerful computers and a lot of calculations, scientists can use the electron density patterns to determine the structure of the protein and make a computer-generated model of the structure. The models let researchers improve their understanding of how the protein functions. They also allow scientists to look for receptor sites and active areas that control a protein's function and role in the progress of diseases. From there, pharmaceutical researchers can design molecules that fit the active site, much like a key and lock, so that the protein is locked without affecting the rest of the body. This is called structure-based drug design.

X ray sensitive area detection device

NASA Technical Reports Server (NTRS)

Carter, Daniel C. (Inventor); Witherow, William K. (Inventor); Pusey, Marc L. (Inventor); Yost, Vaughn H. (Inventor)

1990-01-01

A radiation sensitive area detection device is disclosed which comprises a phosphor-containing film capable of receiving and storing an image formed by a pattern of incoming x rays, UV, or other radiation falling on the film. The device is capable of fluorescing in response to stimulation by a light source in a manner directly proportional to the stored radiation pattern. The device includes: (1) a light source capable of projecting light or other appropriate electromagnetic wave on the film so as to cause it to fluoresce; (2) a means to focus the fluoresced light coming from the phosphor-containing film after light stimulation; and (3) at least one charged coupled detector or other detecting element capable of receiving and digitizing the pattern of fluoresced light coming from the phosphor-containing film. The device will be able to generate superior x ray images of high resolution from a crystal or other sample and will be particularly advantageous in that instantaneous near-real-time images of rapidly deteriorating samples can be obtained. Furthermore, the device can be made compact and sturdy, thus capable of carrying out x ray or other radiation imaging under a variety of conditions, including those experienced in space.

Using iridium films to compensate for piezo-electric materials processing stresses in adjustable x-ray optics

NASA Astrophysics Data System (ADS)

Ames, A.; Bruni, R.; Cotroneo, V.; Johnson-Wilke, R.; Kester, T.; Reid, P.; Romaine, S.; Tolier-McKinstry, S.; Wilke, R. H. T.

2015-09-01

Adjustable X-ray optics represent a potential enabling technology for simultaneously achieving large effective area and high angular resolution for future X-ray Astronomy missions. The adjustable optics employ a bimorph mirror composed of a thin (1.5 μm) film of piezoelectric material deposited on the back of a 0.4 mm thick conical mirror segment. The application of localized electric fields in the piezoelectric material, normal to the mirror surface, result in localized deformations in mirror shape. Thus, mirror fabrication and mounting induced figure errors can be corrected, without the need for a massive reaction structure. With this approach, though, film stresses in the piezoelectric layer, resulting from deposition, crystallization, and differences in coefficient of thermal expansion, can distort the mirror. The large relative thickness of the piezoelectric material compared to the glass means that even 100MPa stresses can result in significant distortions. We have examined compensating for the piezoelectric processing related distortions by the deposition of controlled stress chromium/iridium films on the front surface of the mirror. We describe our experiments with tuning the product of the chromium/iridium film stress and film thickness to balance that resulting from the piezoelectric layer. We also evaluated the repeatability of this deposition process, and the robustness of the iridium coating.

X-ray metal film filters at cryogenic temperatures

NASA Technical Reports Server (NTRS)

Keski-Kuha, Ritva A. M.

1989-01-01

Thin aluminum foil filters have been evaluated at cryogenic temperatures. The results of the test program, including cold cycling and vibration testing, indicate that these filters are fully successful at cryogenic temperatures and can provide the high X-ray transmittance and high background rejection required for the blocking filters which are being developed for the X-Ray Spectrometer, one of the focal plane instruments on the Advanced X-Ray Astrophysics Facility.

Cation distribution in NiZn-ferrite films via extended x-ray absorption fine structure

NASA Astrophysics Data System (ADS)

Harris, V. G.; Koon, N. C.; Williams, C. M.; Zhang, Q.; Abe, M.; Kirkland, J. P.

1996-04-01

We have applied extended x-ray absorption fine structure (EXAFS) spectroscopy to study the cation distribution in a series of spin-sprayed NiZn-ferrite films. A least-squares fitting of experimental EXAFS data with theoretical, multiple-scattering, EXAFS data allowed the quantitative determination of site distributions for all transition metal cations.

Structural anisotropy in amorphous SnO2 film probed by X-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Zhu, Q.; Ma, Q.; Buchholz, D. B.; Chang, R. P. H.; Bedzyk, M. J.; Mason, T. O.

2013-07-01

Polarization-dependent X-ray absorption measurements reveal the existence of structural anisotropy in amorphous (a-) SnO2 film. The anisotropy is readily seen for the second neighbor interaction whose magnitude differs along three measured directions. The differences can be well accounted for by 10%-20% variation in the Debye-Waller factor. Instead of a single Gaussian distribution found in crystalline SnO2, the Sn-O bond distribution is bimodal in a-SnO2 whose separation shows a weak angular dependence. The oxygen vacancies, existing in the a-SnO2 film in the order of 1021 cm-3, distribute preferentially along the film surface direction.

A developer solution for tank processing of x-ray film under ambient, tropical conditions.

PubMed

Wayrynen, R E; McKinney, W E

1976-05-01

A modification of a proprietary 90-sec. x-ray-film developer which permits its use as a hand-tank developer at ambient temperatures between 21.6 degrees-30.6 degrees C (80 degrees-100 degrees F) is described. This processing technique is useful in tropical countries where the control of developer temperature is particularly difficult.

Cadaveric and in vivo human joint imaging based on differential phase contrast by X-ray Talbot-Lau interferometry.

PubMed

Tanaka, Junji; Nagashima, Masabumi; Kido, Kazuhiro; Hoshino, Yoshihide; Kiyohara, Junko; Makifuchi, Chiho; Nishino, Satoshi; Nagatsuka, Sumiya; Momose, Atsushi

2013-09-01

We developed an X-ray phase imaging system based on Talbot-Lau interferometry and studied its feasibility for clinical diagnoses of joint diseases. The system consists of three X-ray gratings, a conventional X-ray tube, an object holder, an X-ray image sensor, and a computer for image processing. The joints of human cadavers and healthy volunteers were imaged, and the results indicated sufficient sensitivity to cartilage, suggesting medical significance. Copyright © 2012. Published by Elsevier GmbH.

Visualisation by high resolution synchrotron X-ray phase contrast micro-tomography of gas films on submerged superhydrophobic leaves.

PubMed

Lauridsen, Torsten; Glavina, Kyriaki; Colmer, Timothy David; Winkel, Anders; Irvine, Sarah; Lefmann, Kim; Feidenhans'l, Robert; Pedersen, Ole

2014-10-01

Floods can completely submerge terrestrial plants but some wetland species can sustain O2 and CO2 exchange with the environment via gas films forming on superhydrophobic leaf surfaces. We used high resolution synchrotron X-ray phase contrast micro-tomography in a novel approach to visualise gas films on submerged leaves of common cordgrass (Spartina anglica). 3D tomograms enabled a hitherto unmatched level of detail regarding the micro-topography of leaf gas films. Gas films formed only on the superhydrophobic adaxial leaf side (water droplet contact angle, Φ=162°) but not on the abaxial side (Φ=135°). The adaxial side of the leaves of common cordgrass is plicate with a longitudinal system of parallel grooves and ridges and the vast majority of the gas film volume was found in large ∼180μm deep elongated triangular volumes in the grooves and these volumes were connected to each neighbouring groove via a fine network of gas tubules (∼1.7μm diameter) across the ridges. In addition to the gas film retained on the leaf exterior, the X-ray phase contrast micro-tomography also successfully distinguished gas spaces internally in the leaf tissues, and the tissue porosity (gas volume per unit tissue volume) ranged from 6.3% to 20.3% in tip and base leaf segments, respectively. We conclude that X-ray phase contrast micro-tomography is a powerful tool to obtain quantitative data of exterior gas features on biological samples because of the significant difference in electron density between air, biological tissues and water. Copyright © 2014 Elsevier Inc. All rights reserved.

A comparison of five methods for monitoring the precision of automated x-ray film processors.

PubMed

Nickoloff, E L; Leo, F; Reese, M

1978-11-01

Five different methods for preparing sensitometric strips used to monitor the precision of automated film processors are compared. A method for determining the sensitivity of each system to processor variations is presented; the observed statistical variability is multiplied by the system response to temperature or chemical changes. Pre-exposed sensitometric strips required the use of accurate densitometers and stringent control limits to be effective. X-ray exposed sensitometric strips demonstrated large variations in the x-ray output (2 omega approximately equal to 8.0%) over a period of one month. Some light sensitometers were capable of detecting +/- 1.0 degrees F (+/- 0.6 degrees C) variations in developer temperature in the processor and/or about 10.0 ml of chemical contamination in the processor. Nevertheless, even the light sensitometers were susceptible to problems, e.g. film emulsion selection, line voltage variations, and latent image fading. Advantages and disadvantages of the various sensitometric methods are discussed.

X-ray phase contrast imaging at MAMI

NASA Astrophysics Data System (ADS)

El-Ghazaly, M.; Backe, H.; Lauth, W.; Kube, G.; Kunz, P.; Sharafutdinov, A.; Weber, T.

2006-05-01

Experiments have been performed to explore the potential of the low emittance 855MeV electron beam of the Mainz Microtron MAMI for imaging with coherent X-rays. Transition radiation from a micro-focused electron beam traversing a foil stack served as X-ray source with good transverse coherence. Refraction contrast radiographs of low absorbing materials, in particular polymer strings with diameters between 30 and 450μm, were taken with a polychromatic transition radiation X-ray source with a spectral distribution in the energy range between 8 and about 40keV. The electron beam spot size had standard deviation σh = (8.6±0.1)μm in the horizontal and σv = (7.5±0.1)μm in the vertical direction. X-ray films were used as detectors. The source-to-detector distance amounted to 11.4m. The objects were placed in a distance of up to 6m from the X-ray film. Holograms of strings were taken with a beam spot size σv = (0.50±0.05)μm in vertical direction, and a monochromatic X-ray beam of 6keV energy. A good longitudinal coherence has been obtained by the (111) reflection of a flat silicon single crystal in Bragg geometry. It has been demonstrated that a direct exposure CCD chip with a pixel size of 13×13μm^2 provides a highly efficient on-line detector. Contrast images can easily be generated with a complete elimination of all parasitic background. The on-line capability allows a minimization of the beam spot size by observing the smallest visible interference fringe spacings or the number of visible fringes. It has been demonstrated that X-ray films are also very useful detectors. The main advantage in comparison with the direct exposure CCD chip is the resolution. For the Structurix D3 (Agfa) X-ray film the standard deviation of the resolution was measured to be σf = (1.2±0.4)μm, which is about a factor of 6 better than for the direct exposure CCD chip. With the small effective X-ray spot size in vertical direction of σv = (1.2±0.3)μm and a geometrical

Dewetting of thin polymer films: an X-ray scattering study

NASA Astrophysics Data System (ADS)

Müller-Buschbaum, P.; Stamm, M.

1998-06-01

The surface morphology of different dewetting states of thin polymer films (polystyrene) on top of silicon substrates was investigated. With diffuse X-ray scattering in the region of total external reflection a high in-plane resolution was achieved. We observe a new nano-dewetting structure which coexists with the well known mesoscopic dewetting structures of holes, cellular pattern and drops. This nano-dewetting structure consists of small dimples with a diameter in the nanometer range. It results from the dewetting of a remaining ultra-thin polymer layer and can be explained with theoretical predictions of spinodal decomposition. The experimental results of the scattering study are confirmed with scanning-force microscopy measurements.

Preferred site occupation of 3 d atoms in NixF e4 -xN (x =1 and 3) films revealed by x-ray absorption spectroscopy and magnetic circular dichroism

NASA Astrophysics Data System (ADS)

Takata, Fumiya; Ito, Keita; Takeda, Yukiharu; Saitoh, Yuji; Takanashi, Koki; Kimura, Akio; Suemasu, Takashi

2018-02-01

X-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism measurements were performed at the Ni and Fe L2 ,3 absorption edges for N ixF e4 -xN (x =1 and 3) epitaxial films. Spectral line-shape analysis and element-specific magnetic moment evaluations are presented. Shoulders at approximately 2 eV above the Ni L2 ,3 main peaks in the XAS spectrum of N i3FeN were interpreted to originate from hybridization of orbitals between Ni 3 d at face-centered (II) sites and N 2 p at body-centered sites, while such features were missing in NiF e3N film. Similar shoulders were observed at Fe L2 ,3 edges in both films. These results indicate that the orbitals of Ni atoms did not hybridize with those of N atoms in the NiF e3N film. Hence, Ni atoms preferentially occupied corner (I) sites, where the hybridization was weak because of the relatively long distance between Ni at I sites and N atoms. The relatively large magnetic moment deduced from sum-rule analysis of NiF e3N also showed a good agreement with the presence of Ni atoms at I sites.

X-ray absorption spectroscopy study of annealing process on Sr1-xLaxCuO2 electron-doped cuprate thin films

NASA Astrophysics Data System (ADS)

Galdi, A.; Orgiani, P.; Sacco, C.; Gobaut, B.; Torelli, P.; Aruta, C.; Brookes, N. B.; Minola, M.; Harter, J. W.; Shen, K. M.; Schlom, D. G.; Maritato, L.

2018-03-01

The superconducting properties of Sr1-xLaxCuO2 thin films are strongly affected by sample preparation procedures, including the annealing step, which are not always well controlled. We have studied the evolution of Cu L2,3 and O K edge x-ray absorption spectra (XAS) of Sr1-xLaxCuO2 thin films as a function of reducing annealing, both qualitatively and quantitatively. By using linearly polarized radiation, we are able to identify the signatures of the presence of apical oxygen in the as-grown sample and its gradual removal as a function of duration of 350 °C Ar annealing performed on the same sample. Even though the as-grown sample appears to be hole doped, we cannot identify the signature of the Zhang-Rice singlet in the O K XAS, and it is extremely unlikely that the interstitial excess oxygen can give rise to a superconducting or even a metallic ground state. XAS and x-ray linear dichroism analyses are, therefore, shown to be valuable tools to improving the control over the annealing process of electron doped superconductors.

Calibration of GafChromic XR-RV3 radiochromic film for skin dose measurement using standardized x-ray spectra and a commercial flatbed scanner

PubMed Central

McCabe, Bradley P.; Speidel, Michael A.; Pike, Tina L.; Van Lysel, Michael S.

2011-01-01

Purpose: In this study, newly formulated XR-RV3 GafChromic® film was calibrated with National Institute of Standards and Technology (NIST) traceability for measurement of patient skin dose during fluoroscopically guided interventional procedures. Methods: The film was calibrated free-in-air to air kerma levels between 15 and 1100 cGy using four moderately filtered x-ray beam qualities (60, 80, 100, and 120 kVp). The calibration films were scanned with a commercial flatbed document scanner. Film reflective density-to-air kerma calibration curves were constructed for each beam quality, with both the orange and white sides facing the x-ray source. A method to correct for nonuniformity in scanner response (up to 25% depending on position) was developed to enable dose measurement with large films. The response of XR-RV3 film under patient backscattering conditions was examined using on-phantom film exposures and Monte Carlo simulations. Results: The response of XR-RV3 film to a given air kerma depended on kVp and film orientation. For a 200 cGy air kerma exposure with the orange side of the film facing the source, the film response increased by 20% from 60 to 120 kVp. At 500 cGy, the increase was 12%. When 500 cGy exposures were performed with the white side facing the x-ray source, the film response increased by 4.0% (60 kVp) to 9.9% (120 kVp) compared to the orange-facing orientation. On-phantom film measurements and Monte Carlo simulations show that using a NIST-traceable free-in-air calibration curve to determine air kerma in the presence of backscatter results in an error from 2% up to 8% depending on beam quality. The combined uncertainty in the air kerma measurement from the calibration curves and scanner nonuniformity correction was ±7.1% (95% C.I.). The film showed notable stability. Calibrations of film and scanner separated by 1 yr differed by 1.0%. Conclusions: XR-RV3 radiochromic film response to a given air kerma shows dependence on beam quality and film

Calibration of GafChromic XR-RV3 radiochromic film for skin dose measurement using standardized x-ray spectra and a commercial flatbed scanner.

PubMed

McCabe, Bradley P; Speidel, Michael A; Pike, Tina L; Van Lysel, Michael S

2011-04-01

In this study, newly formulated XR-RV3 GafChromic film was calibrated with National Institute of Standards and Technology (NIST) traceability for measurement of patient skin dose during fluoroscopically guided interventional procedures. The film was calibrated free-in-air to air kerma levels between 15 and 1100 cGy using four moderately filtered x-ray beam qualities (60, 80, 100, and 120 kVp). The calibration films were scanned with a commercial flatbed document scanner. Film reflective density-to-air kerma calibration curves were constructed for each beam quality, with both the orange and white sides facing the x-ray source. A method to correct for nonuniformity in scanner response (up to 25% depending on position) was developed to enable dose measurement with large films. The response of XR-RV3 film under patient backscattering conditions was examined using on-phantom film exposures and Monte Carlo simulations. The response of XR-RV3 film to a given air kerma depended on kVp and film orientation. For a 200 cGy air kerma exposure with the orange side of the film facing the source, the film response increased by 20% from 60 to 120 kVp. At 500 cGy, the increase was 12%. When 500 cGy exposures were performed with the white side facing the x-ray source, the film response increased by 4.0% (60 kVp) to 9.9% (120 kVp) compared to the orange-facing orientation. On-phantom film measurements and Monte Carlo simulations show that using a NIST-traceable free-in-air calibration curve to determine air kerma in the presence of backscatter results in an error from 2% up to 8% depending on beam quality. The combined uncertainty in the air kerma measurement from the calibration curves and scanner nonuniformity correction was +/- 7.1% (95% C.I.). The film showed notable stability. Calibrations of film and scanner separated by 1 yr differed by 1.0%. XR-RV3 radiochromic film response to a given air kerma shows dependence on beam quality and film orientation. The presence of

X-ray agricultural product inspection: segmentation and classification

NASA Astrophysics Data System (ADS)

Casasent, David P.; Talukder, Ashit; Lee, Ha-Woon

1997-09-01

Processing of real-time x-ray images of randomly oriented and touching pistachio nuts for product inspection is considered. We describe the image processing used to isolate individual nuts (segmentation). This involves a new watershed transform algorithm. Segmentation results on approximately 3000 x-ray (film) and real time x-ray (linescan) nut images were excellent (greater than 99.9% correct). Initial classification results on film images are presented that indicate that the percentage of infested nuts can be reduced to 1.6% of the crop with only 2% of the good nuts rejected; this performance is much better than present manual methods and other automated classifiers have achieved.

X-ray combined analysis of fiber-textured and epitaxial Ba(Sr,Ti)O{sub 3} thin films deposited by radio frequency sputtering

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

Remiens, D.; Ponchel, F.; Legier, J. F.

2011-06-01

A complete study is given in this paper on the structural properties of Ba(Sr,Ti)O{sub 3} (BST) thin films which present various preferred orientations: (111) and (001) fiber and epitaxial textures. The films are deposited in situ at 800 deg. C by sputtering on Si/SiO{sub 2}/TiO{sub x}/Pt substrates and the orientation is controlled by monitoring the concentration of O{sub 2} in the reactive plasma or by prior deposition of a very thin TiO{sub x} buffer layer between BST films and substrates. The epitaxial films are obtained on (001)-alpha-Al{sub 2}O{sub 3} substrates covered with TiO{sub x} buffer layers. In order to analyzemore » finely the preferred orientations, the texture, the microstructural features, and the anisotropy-related quantities such as residual stresses in the films, the conventional Bragg-Brentano {theta} - 2{theta} x-ray diffraction diagrams is shown not to be sufficient. So, we systematically used x-ray combined analysis, a recently developed methodology which gives access to precise determination of the structure (cell parameters and space group) of the films, their orientation distributions (texture strengths and types) and mean crystallite sizes, their residual stresses. This fine structural analysis shows important modifications between the film qualities which induce differences in BST films electrical behavior, permittivity, loss tangent, and tunability.« less

Absolute calibration of Kodak Biomax-MS film response to x rays in the 1.5- to 8-keV energy range

NASA Astrophysics Data System (ADS)

Marshall, F. J.; Knauer, J. P.; Anderson, D.; Schmitt, B. L.

2006-10-01

The absolute response of Kodak Biomax-MS film to x rays in the range from 1.5- to 8-keV has been measured using a laboratory electron-beam generated x-ray source. The measurements were taken at specific line energies by using Bragg diffraction to produce monochromatic beams of x rays. Multiple exposures were taken on Biomax MS film up to levels exceeding optical densities of 2 as measured by a microdensitometer. The absolute beam intensity for each exposure was measured with a Si (Li) detector. Additional response measurements were taken with Kodak direct exposure film (DEF) so as to compare the results of this technique to previously published calibrations. The Biomax-MS results have been fitted to a semiempirical mathematical model (Knauer et al., these proceedings). Users of the model can infer absolute fluences from observed exposure levels at either interpolated or extrapolated energies. To summarize the results: Biomax MS has comparable sensitivity to DEF film below 3keV but has reduced sensitivity above 3keV (˜50%). The lower exposure results from thinner emulsion layers, designed for use with phosphor screens. The ease with which Biomax-MS can be used in place of DEF (same format film, same developing process, and comparable sensitivity) makes it a good replacement.

Confocal total reflection X-ray fluorescence technology based on an elliptical monocapillary and a parallel polycapillary X-ray optics.

PubMed

Zhu, Yu; Wang, Yabing; Sun, Tianxi; Sun, Xuepeng; Zhang, Xiaoyun; Liu, Zhiguo; Li, Yufei; Zhang, Fengshou

2018-07-01

A total reflection X-ray fluorescence (TXRF) spectrometer based on an elliptical monocapillary X-ray lens (MXRL) and a parallel polycapillary X-ray lens (PPXRL) was designed. This TXRF instrument has micro focal spot, low divergence and high intensity of incident X-ray beam. The diameter of the focal spot of MXRL was 16.5 µm, and the divergence of the incident X-ray beam was 3.4 mrad. We applied this TXRF instrument to the micro analysis of a single-layer film containing Ni deposited on a Si substrate by metal vapor vacuum arc ion source. Copyright © 2018 Elsevier Ltd. All rights reserved.

X-ray magnetic spectroscopy of MBE-grown Mn-doped Bi{sub 2}Se{sub 3} thin films

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

Collins-McIntyre, L. J.; Watson, M. D.; Zhang, S. L.

2014-12-15

We report the growth of Mn-doped Bi{sub 2}Se{sub 3} thin films by molecular beam epitaxy (MBE), investigated by x-ray diffraction (XRD), atomic force microscopy (AFM), SQUID magnetometry and x-ray magnetic circular dichroism (XMCD). Epitaxial films were deposited on c-plane sapphire substrates by co-evaporation. The films exhibit a spiral growth mechanism typical of this material class, as revealed by AFM. The XRD measurements demonstrate a good crystalline structure which is retained upon doping up to ∼7.5 atomic-% Mn, determined by Rutherford backscattering spectrometry (RBS), and show no evidence of the formation of parasitic phases. However an increasing interstitial incorporation of Mnmore » is observed with increasing doping concentration. A magnetic moment of 5.1 μ{sub B}/Mn is obtained from bulk-sensitive SQUID measurements, and a much lower moment of 1.6 μ{sub B}/Mn from surface-sensitive XMCD. At ∼2.5 K, XMCD at the Mn L{sub 2,3} edge, reveals short-range magnetic order in the films and indicates ferromagnetic order below 1.5 K.« less

Optimization of X-ray Absorbers for TES Microcalorimeters

NASA Technical Reports Server (NTRS)

Iyomoto, Naoko; Sadleir, John E.; Figueroa-Feliciano, Enectali; Saab, Tarek; Bandler, Simon; Kilbourne, Caroline; Chervenak, James; Talley, Dorothy; Finkbeiner, Fred; Brekosky, Regis

2004-01-01

We have investigated the thermal, electrical, and structural properties of Bi and BiCu films that are being developed as X-ray absorbers for transition-edge sensor (TES) microcalorimeter arrays for imaging X-ray spectroscopy. Bi could be an ideal material for an X-ray absorber due to its high X-ray stopping power and low heat capacity, but it has a low thermal conductivity, which can result in position dependence of the pulses in the absorber. In order to improve the thermal conductivity, we added Cu layers in between the Bi layers. We measured electrical and thermal conductivities of the films around 0.1 K(sub 1) the operating temperature of the TES calorimeter, to examine the films and to determine the optimal thickness of the Cu layer. From the electrical conductivity measurements, we found that the Cu is more resistive on the Bi than on a Si substrate. Together with an SEM picture of the Bi surface, we concluded that the rough surface of the Bi film makes the Cu layer resistive when the Cu layer is not thick enough t o fill in the roughness. From the thermal conductivity measurements, we determined the thermal diffusion constant to be 2 x l0(exp 3) micrometers squared per microsecond in a film that consists of 2.25 micrometers of Bi and 0.1 micrometers of Cu. We measured the position dependence in the film and found that its thermal diffusion constant is too low to get good energy resolution, because of the resistive Cu layer and/or possibly a very high heat capacity of our Bi films. We show plans to improve the thermal diffusion constant in our BiCu absorbers.

Pair distribution functions of amorphous organic thin films from synchrotron X-ray scattering in transmission mode

DOE PAGES

Shi, Chenyang; Teerakapibal, Rattavut; Yu, Lian; ...

2017-07-10

Using high-brilliance high-energy synchrotron X-ray radiation, for the first time the total scattering of a thin organic glass film deposited on a strongly scattering inorganic substrate has been measured in transmission mode. The organic thin film was composed of the weakly scattering pharmaceutical substance indomethacin in the amorphous state. The film was 130 µm thick atop a borosilicate glass substrate of equal thickness. The atomic pair distribution function derived from the thin-film measurement is in excellent agreement with that from bulk measurements. This ability to measure the total scattering of amorphous organic thin films in transmission will enable accurate in situmore » structural studies for a wide range of materials.« less

Pair distribution functions of amorphous organic thin films from synchrotron X-ray scattering in transmission mode

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

Shi, Chenyang; Teerakapibal, Rattavut; Yu, Lian

2017-07-10

Using high-brilliance high-energy synchrotron X-ray radiation, for the first time the total scattering of a thin organic glass film deposited on a strongly scattering inorganic substrate has been measured in transmission mode. The organic thin film was composed of the weakly scattering pharmaceutical substance indomethacin in the amorphous state. The film was 130 µm thick atop a borosilicate glass substrate of equal thickness. The atomic pair distribution function derived from the thin-film measurement is in excellent agreement with that from bulk measurements. This ability to measure the total scattering of amorphous organic thin films in transmission will enable accuratein situstructuralmore » studies for a wide range of materials.« less

Lacquer polishing of X-ray optics

NASA Technical Reports Server (NTRS)

Catura, R. C.; Joki, E. G.; Roethig, D. T.; Brookover, W. J.

1987-01-01

Techniques for polishing figured X-ray optics by a lacquer-coating process are described. This acrylic lacquer coating has been applied with an optical quality of an eighth-wave in red light and very effectively covers surface roughness with spatial wavelengths less than about 0.2 mm. Tungsten films have been deposited on the lacquer coatings to provide highly efficient X-ray reflectivity.

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

NASA Astrophysics Data System (ADS)

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

1995-02-01

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

[Value of chest x-ray films in the diagnosis of congenital heart defects in infants].

PubMed

Koczyński, A

1982-01-01

The respiratory distress and suspicion of the heart defects in newborns and infants is indicated by x-ray chest examinations. The right interpretation of the x-ray pictures is very important but it must be followed by other diagnostic procedures. In every child it is possible to take the linear measurements of the great vessels and arteries in parahilar lung areas as well as the heart and chest in two dimensions from x-ray plain films. The measurements let to establish the indices: cardio-thoracic (ICP), vasculo-cardiac (IVC) and sagittal one (IS), which play important role in radiological evaluation of the chest. It results from the investigated material, that the evaluation of the pulmonary vascular pattern and the indices particularly facilitate the diagnosis of heart deformities coexisting with higher blood flow in pulmonary circulation. Nevertheless the measurements and the indices play the relative role in establishing of the final opinion about the chest and should be considered together with clinical and cardiological data.

Electronic and atomic structures of Ti{sub 1-x}Al{sub x}N thin films related to their damage behavior

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

Tuilier, M.-H.; Pac, M.-J.; Girleanu, M.

2008-04-15

Ti and Al K-edge x-ray absorption spectroscopy is used to investigate the electronic structure of Ti{sub 1-x}Al{sub x}N thin films deposited by reactive magnetron sputtering. The experimental near edge spectra of TiN and AlN are interpreted in the light of unoccupied density of state band structure calculations. The comparison of the structural parameters derived from x-ray absorption fine structure and x-ray diffraction reveals segregation between Al-rich and Ti-rich domains within the Ti{sub 1-x}Al{sub x}N films. Whereas x-ray diffraction probes only the crystallized domains, the structural information derived from extended x-ray absorption fine structure analysis turns on both crystalline and grainmore » boundaries. The results are discussed by considering the damage behavior of the films depending on the composition.« less

High resolution projection X-ray microscope equipped with fluorescent X-ray analyzer and its applications

NASA Astrophysics Data System (ADS)

Minami, K.; Saito, Y.; Kai, H.; Shirota, K.; Yada, K.

2009-09-01

We have newly developed an open type fine-focus X-ray tube "TX-510" to realize a spatial resolution of 50nm and to radiate low energy characteristic X-rays for giving high absorption contrast to images of microscopic organisms. The "TX-510" employs a ZrO/W(100) Schottky emitter and an "In-Lens Field Emission Gun". The key points of the improvements are (1) reduced spherical aberration coefficient of magnetic objective lens, (2) easy and accurate focusing, (3) newly designed astigmatism compensator, (4) segmented thin film target for interchanging the target materials by electron beam shift and (5) fluorescent X-ray analysis system.

The development of efficient X-ray conversion material for digital mammography

NASA Astrophysics Data System (ADS)

Oh, K.; Shin, J.; Kim, S.; Lee, Y.; Jeon, S.; Kim, J.; Nam, S.

2012-02-01

In this study, an experimental method based on theory is used to develop photoconductor that can replace the a-Se currently used as X-ray conversion layer in digital mammography. This is necessary because a-Se produced by the commercial fabrication method, of physical vapor deposition, has exhibited several problems when applied to digital mammography: instability due to crystallization and defect expansion due to high operating voltages, which is called the aging effect. Therefore, our work focused on developing a method of fabricating X-ray conversion films that do not suffer from crystallization and X-ray damage and optimizing the factors affecting the properties of the candidate photoconductors in order to acquire sufficient electrical signals to detect minute calcifications. The photoconductors were initially selected after the requirements for X-ray conversion materials, such as high atomic absorption, density, band-gap energy, work function, and resistivity, were examined. We selected HgI2, PbI2, and PbO because of their basic properties. Next, we experimentally investigated the performance of film samples fabricated by sedimentation and screen printing instead of physical vapor deposition. The structure of the X-ray conversion films (e.g., the thickness, electrodes, and blocking layer) were optimized for the application of a relatively low voltage to the X-ray conversion layer. The performance of the films were morphologically and electrically evaluated under mammography X-ray exposure conditions, and compared with those of a-Se films produced by physical vapor deposition. PbO appeared to be the most suitable alternative material because its electrical properties, such as the dark current, sensitivity, and signal-to-noise ratio (SNR), did not reveal the X-ray damage problem, and thus were maintained after repeated exposure to X-rays. Although PbO showed low sensitivity to X-ray exposure, its SNR was superior to that of the other materials, which is expected

Fluorescence X-ray absorption spectroscopy using a Ge pixel array detector: application to high-temperature superconducting thin-film single crystals.

PubMed

Oyanagi, H; Tsukada, A; Naito, M; Saini, N L; Lampert, M O; Gutknecht, D; Dressler, P; Ogawa, S; Kasai, K; Mohamed, S; Fukano, A

2006-07-01

A Ge pixel array detector with 100 segments was applied to fluorescence X-ray absorption spectroscopy, probing the local structure of high-temperature superconducting thin-film single crystals (100 nm in thickness). Independent monitoring of pixel signals allows real-time inspection of artifacts owing to substrate diffractions. By optimizing the grazing-incidence angle theta and adjusting the azimuthal angle phi, smooth extended X-ray absorption fine structure (EXAFS) oscillations were obtained for strained (La,Sr)2CuO4 thin-film single crystals grown by molecular beam epitaxy. The results of EXAFS data analysis show that the local structure (CuO6 octahedron) in (La,Sr)2CuO4 thin films grown on LaSrAlO4 and SrTiO3 substrates is uniaxially distorted changing the tetragonality by approximately 5 x 10(-3) in accordance with the crystallographic lattice mismatch. It is demonstrated that the local structure of thin-film single crystals can be probed with high accuracy at low temperature without interference from substrates.

Attenuation characteristics of fiberoptic plates for digital mammography and other X-ray imaging applications.

PubMed

Vedantham, S; Karellas, A; Suryanarayanan, S

2003-01-01

Spatially coherent fiberoptic plates are important components of some charge-coupled device (CCD)-based x-ray imaging systems. These plates efficiently transmit scintillations from the phosphor, and also filter out x-rays not absorbed by the phosphor, thus protecting the CCD from direct x-ray interaction. The thickness of the fiberoptic plate and the CCD package present a significant challenge in the design of a digital x-ray cassette capable of insertion into the existing film-screen cassette holders of digital mammography systems. This study was performed with an aim to optimize fiberoptic plate thickness. Attenuation measurements were performed on nine fiberoptic plates varying in material composition that exhibit desirable optical characteristics such as good coupling efficiency. Mammographic spectra from a clinical mammographic system and an Americium-241 (Am-241) source (59.54 KeV) were used. The spectra were recorded with a high-resolution cadmium zinc telluride (CZT)-based spectrometer and corrected for dead time and pile-up. The linear attenuation coefficients varied by a factor of 3 in the set of tested fiberoptic plates at both mammographic energies and 59.54 keV. Our results suggest that a 3-mm thick high-absorption plate might provide adequate for shielding at mammographic energies. A thickness of 2-mm is feasible for mammographic applications with further optimization of the fiberoptic plate composition by incorporating non-scintillating, high-atomic number material. This would allow more space for cooling components of the cassette and for a more compact device, which is critical for clinical implementation of the technology.

Study on the influence of X-ray tube spectral distribution on the analysis of bulk samples and thin films: Fundamental parameters method and theoretical coefficient algorithms

NASA Astrophysics Data System (ADS)

Sitko, Rafał

2008-11-01

Knowledge of X-ray tube spectral distribution is necessary in theoretical methods of matrix correction, i.e. in both fundamental parameter (FP) methods and theoretical influence coefficient algorithms. Thus, the influence of X-ray tube distribution on the accuracy of the analysis of thin films and bulk samples is presented. The calculations are performed using experimental X-ray tube spectra taken from the literature and theoretical X-ray tube spectra evaluated by three different algorithms proposed by Pella et al. (X-Ray Spectrom. 14 (1985) 125-135), Ebel (X-Ray Spectrom. 28 (1999) 255-266), and Finkelshtein and Pavlova (X-Ray Spectrom. 28 (1999) 27-32). In this study, Fe-Cr-Ni system is selected as an example and the calculations are performed for X-ray tubes commonly applied in X-ray fluorescence analysis (XRF), i.e., Cr, Mo, Rh and W. The influence of X-ray tube spectra on FP analysis is evaluated when quantification is performed using various types of calibration samples. FP analysis of bulk samples is performed using pure-element bulk standards and multielement bulk standards similar to the analyzed material, whereas for FP analysis of thin films, the bulk and thin pure-element standards are used. For the evaluation of the influence of X-ray tube spectra on XRF analysis performed by theoretical influence coefficient methods, two algorithms for bulk samples are selected, i.e. Claisse-Quintin (Can. Spectrosc. 12 (1967) 129-134) and COLA algorithms (G.R. Lachance, Paper Presented at the International Conference on Industrial Inorganic Elemental Analysis, Metz, France, June 3, 1981) and two algorithms (constant and linear coefficients) for thin films recently proposed by Sitko (X-Ray Spectrom. 37 (2008) 265-272).

Capability of X-ray diffraction for the study of microstructure of metastable thin films

PubMed Central

Rafaja, David; Wüstefeld, Christina; Dopita, Milan; Motylenko, Mykhaylo; Baehtz, Carsten

2014-01-01

Metastable phases are often used to design materials with outstanding properties, which cannot be achieved with thermodynamically stable compounds. In many cases, the metastable phases are employed as precursors for controlled formation of nanocomposites. This contribution shows how the microstructure of crystalline metastable phases and the formation of nanocomposites can be concluded from X-ray diffraction experiments by taking advantage of the high sensitivity of X-ray diffraction to macroscopic and microscopic lattice deformations and to the dependence of the lattice deformations on the crystallographic direction. The lattice deformations were determined from the positions and from the widths of the diffraction lines, the dependence of the lattice deformations on the crystallographic direction from the anisotropy of the line shift and the line broadening. As an example of the metastable system, the supersaturated solid solution of titanium nitride and aluminium nitride was investigated, which was prepared in the form of thin films by using cathodic arc evaporation of titanium and aluminium in a nitrogen atmosphere. The microstructure of the (Ti,Al)N samples under study was tailored by modifying the [Al]/[Ti] ratio in the thin films and the surface mobility of the deposited species. PMID:25485125

Projection x-ray topography system at 1-BM x-ray optics test beamline at the advanced photon source

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

Stoupin, Stanislav, E-mail: sstoupin@aps.anl.gov; Liu, Zunping; Trakhtenberg, Emil

2016-07-27

Projection X-ray topography of single crystals is a classic technique for the evaluation of intrinsic crystal quality of large crystals. In this technique a crystal sample and an area detector (e.g., X-ray film) collecting intensity of a chosen crystallographic reflection are translated simultaneously across an X-ray beam collimated in the diffraction scattering plane (e.g., [1, 2]). A bending magnet beamline of a third-generation synchrotron source delivering x-ray beam with a large horizontal divergence, and therefore, a large horizontal beam size at a crystal sample position offers an opportunity to obtain X-ray topographs of large crystalline samples (e.g., 6-inch wafers) inmore » just a few exposures. Here we report projection X-ray topography system implemented recently at 1-BM beamline of the Advanced Photon Source. A selected X-ray topograph of a 6-inch wafer of 4H-SiC illustrates capabilities and limitations of the technique.« less

SMART-X: Square Meter, Arcsecond Resolution Telescope for X-rays

NASA Astrophysics Data System (ADS)

Vikhlinin, Alexey; SMART-X Collaboration

2013-04-01

SMART-X is a concept for a next-generation X-ray observatory with large-area, 0.5" angular resolution grazing incidence adjustable X-ray mirrors, high-throughput critical angle transmission gratings, and X-ray microcalorimeter and CMOS-based imager in the focal plane. High angular resolution is enabled by new technology based on controlling the shape of mirror segments using thin film piezo actuators deposited on the back surface. Science applications include observations of growth of supermassive black holes since redshifts of ~10, ultra-deep surveys over 10's of square degrees, galaxy assembly at z=2-3, as well as new opportunities in the high-resolution X-ray spectroscopy and time domains. We also review the progress in technology development, tests, and mission design over the past year.

Anisotropic spin-density distribution and magnetic anisotropy of strained La1-xSrxMnO3 thin films: angle-dependent x-ray magnetic circular dichroism

NASA Astrophysics Data System (ADS)

Shibata, Goro; Kitamura, Miho; Minohara, Makoto; Yoshimatsu, Kohei; Kadono, Toshiharu; Ishigami, Keisuke; Harano, Takayuki; Takahashi, Yukio; Sakamoto, Shoya; Nonaka, Yosuke; Ikeda, Keisuke; Chi, Zhendong; Furuse, Mitsuho; Fuchino, Shuichiro; Okano, Makoto; Fujihira, Jun-ichi; Uchida, Akira; Watanabe, Kazunori; Fujihira, Hideyuki; Fujihira, Seiichi; Tanaka, Arata; Kumigashira, Hiroshi; Koide, Tsuneharu; Fujimori, Atsushi

2018-01-01

Magnetic anisotropies of ferromagnetic thin films are induced by epitaxial strain from the substrate via strain-induced anisotropy in the orbital magnetic moment and that in the spatial distribution of spin-polarized electrons. However, the preferential orbital occupation in ferromagnetic metallic La1-xSrxMnO3 (LSMO) thin films studied by x-ray linear dichroism (XLD) has always been found out-of-plane for both tensile and compressive epitaxial strain and hence irrespective of the magnetic anisotropy. In order to resolve this mystery, we directly probed the preferential orbital occupation of spin-polarized electrons in LSMO thin films under strain by angle-dependent x-ray magnetic circular dichroism (XMCD). Anisotropy of the spin-density distribution was found to be in-plane for the tensile strain and out-of-plane for the compressive strain, consistent with the observed magnetic anisotropy. The ubiquitous out-of-plane preferential orbital occupation seen by XLD is attributed to the occupation of both spin-up and spin-down out-of-plane orbitals in the surface magnetic dead layer.

Microfabrication of High Resolution X-ray Magnetic Calorimeters

NASA Astrophysics Data System (ADS)

Hsieh, Wen-Ting; Bandler, Simon R.; Kelly, Daniel P.; Porst, Jan P.; Rotzinger, Hannes; Seidel, George M.; Stevenson, Thomas R.

2009-12-01

Metallic magnetic calorimeter (MMC) is one of the most promising x-ray detector technologies for providing the very high energy resolution needed for future astronomical x-ray imaging spectroscopy. For this purpose, we have developed micro-fabricated 5×5 arrays of MMC of which each individual pixel has excellent energy resolution as good as 3.4 eV at 6 keV x-ray. Here we report on the fabrication techniques developed to achieve good resolution and high efficiency. These include: processing of a thin insulation layer for strong magnetic coupling between the AuEr sensor film and the niobium pick-up coil; production of overhanging absorbers for enhanced efficiency of x-ray absorption; fabrication on SiN membranes to minimize the effects on energy resolution from athermal phonon loss. We have also improved the deposition of the magnetic sensor film such that the film magnetization is nearly completely that is expected from the AuEr sputter target bulk material. In addition, we have included a study of a positional sensitive design, the Hydra design, which allows thermal coupling of four absorbers to a common MMC sensor and circuit.

Absolute calibration of Kodak Biomax-MS film response to x rays in the 1.5- to 8-keV energy range

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

Marshall, F. J.; Knauer, J. P.; Anderson, D.

2006-10-15

The absolute response of Kodak Biomax-MS film to x rays in the range from 1.5- to 8-keV has been measured using a laboratory electron-beam generated x-ray source. The measurements were taken at specific line energies by using Bragg diffraction to produce monochromatic beams of x rays. Multiple exposures were taken on Biomax MS film up to levels exceeding optical densities of 2 as measured by a microdensitometer. The absolute beam intensity for each exposure was measured with a Si(Li) detector. Additional response measurements were taken with Kodak direct exposure film (DEF) so as to compare the results of this techniquemore » to previously published calibrations. The Biomax-MS results have been fitted to a semiempirical mathematical model (Knauer et al., these proceedings). Users of the model can infer absolute fluences from observed exposure levels at either interpolated or extrapolated energies. To summarize the results: Biomax MS has comparable sensitivity to DEF film below 3 keV but has reduced sensitivity above 3 keV ({approx}50%). The lower exposure results from thinner emulsion layers, designed for use with phosphor screens. The ease with which Biomax-MS can be used in place of DEF (same format film, same developing process, and comparable sensitivity) makes it a good replacement.« less

Real-time growth study of plasma assisted atomic layer epitaxy of InN films by synchrotron x-ray methods

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

Nepal, Neeraj; Anderson, Virginia R.; Johnson, Scooter D.

The temporal evolution of high quality indium nitride (InN) growth by plasma-assisted atomic layer epitaxy (ALEp) on a-plane sapphire at 200 and 248 °C was probed by synchrotron x-ray methods. The growth was carried out in a thin film growth facility installed at beamline X21 of the National Synchrotron Light Source at Brookhaven National Laboratory and at beamline G3 of the Cornell High Energy Synchrotron Source, Cornell University. Measurements of grazing incidence small angle x-ray scattering (GISAXS) during the initial cycles of growth revealed a broadening and scattering near the diffuse specular rod and the development of scattering intensities duemore » to half unit cell thick nucleation islands in the Yoneda wing with correlation length scale of 7.1 and 8.2 nm, at growth temperatures (Tg) of 200 and 248 °C, respectively. At about 1.1 nm (two unit cells) of growth thickness nucleation islands coarsen, grow, and the intensity of correlated scattering peak increased at the correlation length scale of 8.0 and 8.7 nm for Tg = 200 and 248 °C, respectively. The correlated peaks at both growth temperatures can be fitted with a single peak Lorentzian function, which support single mode growth. Post-growth in situ x-ray reflectivity measurements indicate a growth rate of ~0.36 Å/cycle consistent with the growth rate previously reported for self-limited InN growth in a commercial ALEp reactor. Consistent with the in situ GISAXS study, ex situ atomic force microscopy power spectral density measurements also indicate single mode growth. Electrical characterization of the resulting film revealed an electron mobility of 50 cm2/V s for a 5.6 nm thick InN film on a-plane sapphire, which is higher than the previously reported mobility of much thicker InN films grown at higher temperature by molecular beam epitaxy directly on sapphire. These early results indicated that in situ synchrotron x-ray study of the epitaxial growth kinetics of InN films is a very powerful

Experimental study and analytical model of deformation of magnetostrictive films as applied to mirrors for x-ray space telescopes.

PubMed

Wang, Xiaoli; Knapp, Peter; Vaynman, S; Graham, M E; Cao, Jian; Ulmer, M P

2014-09-20

The desire for continuously gaining new knowledge in astronomy has pushed the frontier of engineering methods to deliver lighter, thinner, higher quality mirrors at an affordable cost for use in an x-ray observatory. To address these needs, we have been investigating the application of magnetic smart materials (MSMs) deposited as a thin film on mirror substrates. MSMs have some interesting properties that make the application of MSMs to mirror substrates a promising solution for making the next generation of x-ray telescopes. Due to the ability to hold a shape with an impressed permanent magnetic field, MSMs have the potential to be the method used to make light weight, affordable x-ray telescope mirrors. This paper presents the experimental setup for measuring the deformation of the magnetostrictive bimorph specimens under an applied magnetic field, and the analytical and numerical analysis of the deformation. As a first step in the development of tools to predict deflections, we deposited Terfenol-D on the glass substrates. We then made measurements that were compared with the results from the analytical and numerical analysis. The surface profiles of thin-film specimens were measured under an external magnetic field with white light interferometry (WLI). The analytical model provides good predictions of film deformation behavior under various magnetic field strengths. This work establishes a solid foundation for further research to analyze the full three-dimensional deformation behavior of magnetostrictive thin films.

Simultaneous parameter optimization of x-ray and neutron reflectivity data using genetic algorithms

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

Singh, Surendra, E-mail: surendra@barc.gov.in; Basu, Saibal

2016-05-23

X-ray and neutron reflectivity are two non destructive techniques which provide a wealth of information on thickness, structure and interracial properties in nanometer length scale. Combination of X-ray and neutron reflectivity is well suited for obtaining physical parameters of nanostructured thin films and superlattices. Neutrons provide a different contrast between the elements than X-rays and are also sensitive to the magnetization depth profile in thin films and superlattices. The real space information is extracted by fitting a model for the structure of the thin film sample in reflectometry experiments. We have applied a Genetic Algorithms technique to extract depth dependentmore » structure and magnetic in thin film and multilayer systems by simultaneously fitting X-ray and neutron reflectivity data.« less

Flexible digital x-ray technology for far-forward remote diagnostic and conformal x-ray imaging applications

NASA Astrophysics Data System (ADS)

Smith, Joseph; Marrs, Michael; Strnad, Mark; Apte, Raj B.; Bert, Julie; Allee, David; Colaneri, Nicholas; Forsythe, Eric; Morton, David

2013-05-01

Today's flat panel digital x-ray image sensors, which have been in production since the mid-1990s, are produced exclusively on glass substrates. While acceptable for use in a hospital or doctor's office, conventional glass substrate digital x-ray sensors are too fragile for use outside these controlled environments without extensive reinforcement. Reinforcement, however, significantly increases weight, bulk, and cost, making them impractical for far-forward remote diagnostic applications, which demand rugged and lightweight x-ray detectors. Additionally, glass substrate x-ray detectors are inherently rigid. This limits their use in curved or bendable, conformal x-ray imaging applications such as the non-destructive testing (NDT) of oil pipelines. However, by extending low-temperature thin-film transistor (TFT) technology previously demonstrated on plastic substrate- based electrophoretic and organic light emitting diode (OLED) flexible displays, it is now possible to manufacture durable, lightweight, as well as flexible digital x-ray detectors. In this paper, we discuss the principal technical approaches used to apply flexible display technology to two new large-area flexible digital x-ray sensors for defense, security, and industrial applications and demonstrate their imaging capabilities. Our results include a 4.8″ diagonal, 353 x 463 resolution, flexible digital x-ray detector, fabricated on a 6″ polyethylene naphthalate (PEN) plastic substrate; and a larger, 7.9″ diagonal, 720 x 640 resolution, flexible digital x-ray detector also fabricated on PEN and manufactured on a gen 2 (370 x 470 mm) substrate.

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

NASA Astrophysics Data System (ADS)

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

2000-06-01

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

Intensities of Incident and Transmitted Ultraviolet-A Rays through Gafchromic Films

PubMed Central

Katsuda, Toshizo; Gotanda, Rumi; Gotanda, Tatsuhiro; Akagawa, Takuya; Tanki, Nobuyoshi; Kuwano, Tadao; Noguchi, Atsushi; Yabunaka, Kouichi

2017-01-01

Gafchromic films have been applied to X-ray dosimetry in diagnostic radiology. To correct nonuniformity errors in Gafchromic films, X-rays in the double-exposure technique can be replaced with ultraviolet (UV)-A rays. Intensities of the incident and transmitted UV-A rays were measured. However, it is unclear whether the chemical color change of Gafchromic films affects the UV-A transmission intensity. Gafchromic EBT3 films were suitable to be used in this study because non-UV protection layers are present on both sides of the film. The film is placed between UV-A ray light-emitting diodes and a probe of a UV meter. Gafchromic EBT3 films were irradiated by UV-A rays for up to 60 min. Data for analysis were obtained in the subsequent 60 min. Images from before and after UV-A irradiation were subtracted. When using 375 nm UV-A, the mean ± standard deviation (SD) of the pixel values in the subtracted image was remarkably high (11,194.15 ± 586.63). However, the UV-A transmissivity remained constant throughout the 60 min irradiation period. The mean ± SD UV-A transmission intensity was 184.48 ± 0.50 μm/cm2. Our findings demonstrate that color density changes in Gafchromic EBT3 films do not affect their UV-A transmission. Therefore, Gafchromic films were irradiated by UV-A rays as a preexposure. PMID:28706354

X-ray structural investigation of nonsymmetrically and symmetrically alkylated [1]benzothieno[3,2-b]benzothiophene derivatives in bulk and thin films.

PubMed

Gbabode, Gabin; Dohr, Michael; Niebel, Claude; Balandier, Jean-Yves; Ruzié, Christian; Négrier, Philippe; Mondieig, Denise; Geerts, Yves H; Resel, Roland; Sferrazza, Michele

2014-08-27

A detailed structural study of the bulk and thin film phases observed for two potential high-performance organic semiconductors has been carried out. The molecules are based on [1]benzothieno[3,2-b]benzothiophene (BTBT) as conjugated core and octyl side groups, which are anchored either symmetrically at both sides of the BTBT core (C8-BTBT-C8) or nonsymmetrically at one side only (C8-BTBT). Thin films of different thickness (8-85 nm) have been prepared by spin-coating for both systems and analyzed by combining specular and grazing incidence X-ray diffraction. In the case of C8-BTBT-C8, the known crystal structure obtained from single-crystal investigations is observed within all thin films, down to a film thickness of 9 nm. In the case of C8-BTBT, the crystal structure of the bulk phase has been determined from X-ray powder diffraction data with a consistent matching of experimental and calculated X-ray diffraction patterns (Rwp = 5.8%). The packing arrangement of C8-BTBT is similar to that of C8-BTBT-C8, that is, consisting of a lamellar structure with molecules arranged in a "herringbone" fashion, yet with lamellae composed of two head-to-head (or tail-to-tail as the structure is periodic) superimposed molecules instead of only one molecule for C8-BTBT-C8. As for C8-BTBT-C8, we demonstrate that the same phase is observed in bulk and thin films for C8-BTBT whatever the film thickness investigated.

In-situ Synchrotron X-ray Studies of the Microstructure and Stability of In 2O 3 Epitaxial Films

DOE PAGES

Highland, M. J.; Hruszkewycz, S. O.; Fong, D. D.; ...

2017-10-16

Here, we report on the synthesis, stability, and local structure of In 2O 3 thin films grown via rf-magnetron sputtering and characterized by in-situ x-ray scattering and focused x-ray nanodiffraction. We find that In 2O 3 deposited onto (001)-oriented single crystal yttria-stabilized zirconia substrates adopts a Stranski–Krastanov growth mode at a temperature of 850°C, resulting in epitaxial, truncated square pyramids with (111) side walls. We find that at this temperature, the pyramids evaporate unless they are stabilized by a low flux of In 2O 3 from the magnetron source. Lastly, we also find that the internal lattice structure of onemore » such pyramid is made up of differently strained volumes, revealing local structural heterogeneity that may impact the properties of In 2O 3 nanostructures and films.« less

Characterization of linear accelerator X-ray source size using a laminated beam-spot camera.

PubMed

Yeboah, Collins

2011-05-10

A laminated beam-spot camera of length 20 cm and effective cross-sectional area 2.5 cm × 3 cm was designed and constructed for the measurement of X-ray beam-spot sizes on different models of Siemens accelerators. With the accelerator gantry at 180° and camera positioned on an accessory tray holder, an XV film placed in contact with the camera at the distal end of it detected those X-rays that were transmitted through the camera. The FWHM of the detected X-ray intensity profile in the gun-target (G-T) direction or the orthogonal A-B direction was used as a measure of the beam-spot size in that direction. Siemens Mevatron MXEs exhibited a beam-spot size of 1.7 ± 0.2 mm in both the in-plane and cross-plane directions for 6 MV photon beams. The beam-spot size observed for a Mevatron MDX-2 was larger by up to 1 mm, and also was different for the in-plane and cross-plane directions. For Siemens PRIMUS accelerators, the beam-spot size in the in-plane direction was found to fall in the range 2.0-2.2 ± 0.2 mm, whereas the beam-spot size in the cross-plane direction fell within 1.7-1.9 ± 0.2 mm for 6, 10, and 18 MV photon beams. Assessment of long-term stability of the beam-spot size shows the spot size remains fairly stable over time.

[Microfabricated X-ray Optics Technology Development for the Constellation X-Mission

NASA Technical Reports Server (NTRS)

Schattenburg, Mark L.

2005-01-01

MIT has previously developed advanced methods for the application of silicon microstructures (so-called microcombs) in the precision assembly of foil x-ray optics in support of the Constellation-X Spectroscopy X-ray Telescope (SXT) technology development at the NASA Goddard Space Flight Center (GSFC). During the first year of the above Cooperative Agreement, MIT has developed a new, mature, potentially high- yield process for the manufacturing of microcombs that can be applied to a range of substrates independent of thickness. MIT also developed techniques to extract microcomb accuracy from an assembly truss metrology test stand and to extend the dynamic range of its Shack-Hartmann foil metrology tool. The placement repeatability of foil optics with microcombs in the assembly truss has been improved by a factor of two to approximately 0.15 micron. This was achieved by electric contact determination in favor of determining contact through force measurements. Development work on a stress-free thin foil holder was also supported by this agreement and successfully continued under a different grant.

Solar x ray astronomy rocket program

NASA Technical Reports Server (NTRS)

1990-01-01

The dynamics were studied of the solar corona through the imaging of large scale coronal structures with AS&E High Resolution Soft X ray Imaging Solar Sounding Rocket Payload. The proposal for this program outlined a plan of research based on the construction of a high sensitivity X ray telescope from the optical and electronic components of the previous flight of this payload (36.038CS). Specifically, the X ray sensitive CCD camera was to be placed in the prime focus of the grazing incidence X ray mirror. The improved quantum efficiency of the CCD detector (over the film which had previously been used) allows quantitative measurements of temperature and emission measure in regions of low x ray emission such as helmet streamers beyond 1.2 solar radii or coronal holes. Furthermore, the improved sensitivity of the CCD allows short exposures of bright objects to study unexplored temporal regimes of active region loop evolution.

Photoinduced coherent acoustic phonon dynamics inside Mott insulator Sr2IrO4 films observed by femtosecond X-ray pulses

NASA Astrophysics Data System (ADS)

Zhang, Bing-Bing; Liu, Jian; Wei, Xu; Sun, Da-Rui; Jia, Quan-Jie; Li, Yuelin; Tao, Ye

2017-04-01

We investigate the transient photoexcited lattice dynamics in a layered perovskite Mott insulator Sr2IrO4 film by femtosecond X-ray diffraction using a laser plasma-based X-ray source. The ultrafast structural dynamics of Sr2IrO4 thin films are determined by observing the shift and broadening of (0012) Bragg diffraction after excitation by 1.5 eV and 3.0 eV pump photons for films with different thicknesses. The observed transient lattice response can be well interpreted as a distinct three-step dynamics due to the propagation of coherent acoustic phonons generated by photoinduced quasiparticles (QPs). Employing a normalized phonon propagation model, we found that the photoinduced angular shifts of the Bragg peak collapse into a universal curve after introducing normalized coordinates to account for different thicknesses and pump photon energies, pinpointing the origin of the lattice distortion and its early evolution. In addition, a transient photocurrent measurement indicates that the photoinduced QPs are charge neutral excitons. Mapping the phonon propagation and correlating its dynamics with the QP by ultrafast X-ray diffraction (UXRD) establish a powerful way to study electron-phonon coupling and uncover the exotic physics in strongly correlated systems under nonequilibrium conditions.

JEUMICO: Czech-Bavarian astronomical X-ray optics project

NASA Astrophysics Data System (ADS)

Hudec, R.; Döhring, T.

2017-07-01

Within the project JEUMICO, an acronym for "Joint European Mirror Competence", the Aschaffenburg University of Applied Sciences and the Czech Technical University in Prague started a collaboration to develop mirrors for X-ray telescopes. Corresponding mirror segments use substrates of flat silicon wafers which are coated with thin iridium films, as this material is promising high reflectivity in the X-ray range of interest. The sputtering parameters are optimized in the context of the expected reflectivity of the coated X-ray mirrors. In near future measurements of the assembled mirror modules optical performances are planned at an X-ray test facility.

Electron-Beam Deposition of Superconducting Molybdenum Thin Films for the Development of Mo/Au TES X-Ray Microcalorimeter

NASA Technical Reports Server (NTRS)

Finkbeiner, Fred Michael; Adams, Joseph S.; Bandler, Simon R.; Betancour-Martinez, Gabriele L.; Brown, Ari David; Chang, Meng-Ping; Chervenak, James A.; Chiao, Meng P.; Datesman, Aaron; Eckart, Megan E.;

X-ray imaging of fibers

NASA Astrophysics Data System (ADS)

Moosman, B.; Song, Y.; Weathers, L.; Wessel, F.

1996-11-01

A pulsed x-ray backlighter was developed to image exploding wires and cryogenic fibers. The x-ray pulse width is between 10-20 ns, with an output of 100-150 mJ, mostly in the Al k-shell (1.486 keV). The backlighter is located 50 cm from the 20-50 micron diameter target (typically, a copper wire). A 15 micron Al filter eliminates UV emission from the backlighter and target. It is placed 3 cm from the target with SB-5 film directly behind it. From the optical density of the film, target absorption and density can be calculated. The spatial resolution of this system is better than 40 microns. The wire is exploded using a 10 kA, 1 microsecond pulser. Analysis with simultaneous Moire imaging will also be presented. Supported by Los Alamos National Laboratories

Note: application of a pixel-array area detector to simultaneous single crystal X-ray diffraction and X-ray absorption spectroscopy measurements.

PubMed

Sun, Cheng-Jun; Zhang, Bangmin; Brewe, Dale L; Chen, Jing-Sheng; Chow, G M; Venkatesan, T; Heald, Steve M

2014-04-01

X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are two main x-ray techniques in synchrotron radiation facilities. In this Note, we present an experimental setup capable of performing simultaneous XRD and XAS measurements by the application of a pixel-array area detector. For XRD, the momentum transfer in specular diffraction was measured by scanning the X-ray energy with fixed incoming and outgoing x-ray angles. By selecting a small fixed region of the detector to collect the XRD signal, the rest of the area was available for collecting the x-ray fluorescence for XAS measurements. The simultaneous measurement of XRD and X-ray absorption near edge structure for Pr0.67Sr0.33MnO3 film was demonstrated as a proof of principle for future time-resolved pump-probe measurements. A static sample makes it easy to maintain an accurate overlap of the X-ray spot and laser pump beam.

X-ray diffraction from shock-loaded polycrystals.

PubMed

Swift, Damian C

2008-01-01

X-ray diffraction was demonstrated from shock-compressed polycrystalline metals on nanosecond time scales. Laser ablation was used to induce shock waves in polycrystalline foils of Be, 25-125 microm thick. A second laser pulse was used to generate a plasma x-ray source by irradiation of a Ti foil. The x-ray source was collimated to produce a beam of controllable diameter, which was directed at the Be sample. X-rays were diffracted from the sample, and detected using films and x-ray streak cameras. The diffraction angle was observed to change with shock pressure. The diffraction angles were consistent with the uniaxial (elastic) and isotropic (plastic) compressions expected for the loading conditions used. Polycrystalline diffraction will be used to measure the response of the crystal lattice to high shock pressures and through phase changes.

A normal incidence X-ray telescope

NASA Technical Reports Server (NTRS)

Golub, Leon

1987-01-01

The postflight performance evaluation of the X-ray telescope was summarized. All payload systems and subsystems performed well within acceptable limits, with the sole exception of the light-blocking prefilters. Launch, flight and recovery were performed in a fully satisfactory manner. The payload was recovered in a timely manner and in excellent condition. The prefilter performance analysis showed that no X-ray images were detected on the processed flight film. Recommendations for improved performance are listed.

75 FR 41894 - Carestream Health, Inc. Medical X-Ray Division Windsor, CO; Amended Certification Regarding...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-19

.... Medical X-Ray Division Windsor, CO; Amended Certification Regarding Eligibility To Apply for Worker... Carestream Health, Inc., X-Ray/Mammography Film Division, Windsor, Colorado. The notice was published in the... medical x-ray film. New information shows that the subject firm name was not identified in its entirety...

The geometry of three-dimensional measurement from paired coplanar x-ray images.

PubMed

Baumrind, S; Moffitt, F H; Curry, S

1983-10-01

This article outlines the geometric principles which underlie the process of making craniofacial measurements in three dimensions by combining information from pairs of coplanar x-ray images. The main focus is upon the rationale of the method rather than upon the computational details. We stress particularly the importance of having available accurate measurements as to the relative positions of the x-ray tubes and the film plane. The use of control arrays of radiopaque "points" whose projected images upon the film plane allow the retrospective calculation of the spatial relationship between the x-ray tubes and the film plane is explained. Finally, the question of correcting for movement of the subject between two films of an image pair is considered briefly.

Image plates as x-ray detectors in plasma physics experiments

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

Gales, S.G.; Bentley, C.D.

2004-10-01

The performance of image plates based on the photostimulable phosphor BaF(Br,l):Eu{sup 2+} has been investigated and compared with x-ray film. Evaluation of detective quantum efficiency (DQE), sensitivity, dynamic range, and linearity was carried out for several types of commercially available image plate, using the Excalibur soft x-ray calibration facility at AWE. Image plate response was found to be linear over a dynamic range of 5 orders of magnitude. One type of image plate was found to have a number of advantages for soft x-ray detection, with a measured sensitivity 1 order of magnitude greater than that of Kodak Industrex CXmore » and DEF-5 x-ray film. The DQE of this plate was found to be superior to that of film at low [less than 10{sup 3} photons/(50 {mu}m){sup 2}] and high fluxes [greater than 10{sup 4} photons/(50 {mu}m){sup 2}]. The spatial resolution of image plates, scanned with several models of commercial image plate readers, has been evaluated using a USAF resolution test target. The highest spatial resolution measured is 35 {mu}m. Though this is significantly lower than the resolution possible with film, it is sufficient for many applications. Image plates were fielded in a refractive x-ray lens imaging diagnostic on the 1 TW Helen laser and these results are discussed.« less

Correcting and coating thin walled X-ray Optics via a combination of controlled film deposition and magnetic smart materials

NASA Astrophysics Data System (ADS)

Ulmer, Melville

The project goal is to demonstrate that thin walled (<400 micron thick) X-ray optics can be controllably shaped to produce high quality (~1" or better) X-ray optics at an affordable price. Since the desired surface area for the next generation X-ray telescope is >10x that of Chandra, the >10x requirement is then for >200 m^2 of surface area with a surface finish of better than 0.5 nm. Therefore, replication of some sort is called for. Because no replication technology has been shown to achieve ≤1" angular resolution, post fabrication figure corrections are likely going to be necessary. Some have proposed to do this in orbit and others prelaunch including us. Our prelaunch approach is to apply in-plane stresses to the thin walled mirror shells via a magnetic field. The field will be held in by some magnetically hard material such as NiCo. By use of a so called magnetic smart material (MSM) such as Terfenol-D, we already shown that strong enough stresses can be generated. Preliminary work has also shown that the magnetic field can be held in well enough to apply the figure correcting stresses pre-launch. What we call "set-it and forget-it." However, what is unique about our approach is that at the cost of complexity and some areal coverage, our concept will also accommodate in-orbit adjustments. Furthermore, to the best of our knowledge ours is one of two known stress modification processes that are bi-axial. Our plan is first to validate set-it and forget-it first on cantilevers and then to expand this to working on 5 cm x 5 cm pieces. We will work both with NiCo and glass or Si coated with Terfenol-D. Except for the NiCo, substrates we will also coat the samples with NiCo in order to have a film that will hold in the magnetic field. As part of the coating process, we will control the stress of the film by varying the voltage bias while coating. The bias stress control can be used to apply films with minimal stress such as Terfenol-D and X-ray reflecting coatings

Fabrication process for a gradient index x-ray lens

DOEpatents

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

1995-01-17

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

Fabrication process for a gradient index x-ray lens

DOEpatents

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

1995-01-01

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

An audit of rejected repeated x-ray films as a quality assurance element in a radiology department.

PubMed

Eze, K C; Omodia, N; Okegbunam, B; Adewonyi, T; Nzotta, C C

2008-12-01

To find out the causes, number, percentage and sizes of rejected radiographic films with a view of adopting measures that will reduce the rate and number of rejected films. Radiology Department of a University Teaching Hospital. Over a two-year period (1st April 2002 to 31st March 2004), the total number of x-ray films utilized for radiographic examinations, rejected films and sizes of rejected films were collected retrospectively from the medical record of radiology department. All the rejected films were viewed by a radiologist and three radiographers for the causes of the rejects which was arrived at by consensus. The data was analysed. A total of 15,095 films were used in the study period and 1,338 films (8.86%) were rejected or wasted. The rate of rejected films varied from 7.69% to 13.82% with average of 8.86%. The greatest cause of film rejects was radiographers' faults 547 (40.88%), followed by equipments faults 255 (19.06%), and patients' faults 250 (18.90%). The highest reject rate (13.82%) was for films used for examination of the spine (15 x 30) cm size. This is followed by 9.92% for skull (18 x 24) cm films and 8.83% for small sized films (24 x 30) cm used for paediatric patients. Of a total of 1,338 rejected films, 1276 (95.37%) additional exposure were done to obtain the basic desired diagnostic information involving 1151 patients; 885 (76.89%) of these patients needed at least one additional hospital visit to take the repeat exposure. Rejected films are not billable; patients receive additional radiation and may even come to hospital in another day for the repeat. Radiographer's work is increased as well as that of the support staff. The waiting room may be congested and waiting time increased. The cost of processing chemical and films are increased, thus if work is quantified in monetary terms, the cost of repeats is high. Rejected-repeated film analysis is cheap, simple, practicable, easy to interpret and an effective indictor of quality assurance

Thin-film preparation by back-surface irradiation pulsed laser deposition using metal powder targets

NASA Astrophysics Data System (ADS)

Kawasaki, Hiroharu; Ohshima, Tamiko; Yagyu, Yoshihito; Ihara, Takeshi; Yamauchi, Makiko; Suda, Yoshiaki

2017-01-01

Several kinds of functional thin films were deposited using a new thin-film preparation method named the back-surface irradiation pulsed laser deposition (BIPLD) method. In this BIPLD method, powder targets were used as the film source placed on a transparent target holder, and then a visible-wavelength pulsed laser was irradiated from the holder side to the substrate. Using this new method, titanium oxide and boron nitride thin films were deposited on the silicon substrate. Surface scanning electron microscopy (SEM) images suggest that all of the thin films were deposited on the substrate with some large droplets irrespective of the kind of target used. The deposition rate of the films prepared by using this method was calculated from film thickness and deposition time to be much lower than that of the films prepared by conventional PLD. X-ray diffraction (XRD) measurement results suggest that rutile and anatase TiO2 crystal peaks were formed for the films prepared using the TiO2 rutile powder target. Crystal peaks of hexagonal boron nitride were observed for the films prepared using the boron nitride powder target. The crystallinity of the prepared films was changed by annealing after deposition.

A flexible and accurate quantification algorithm for electron probe X-ray microanalysis based on thin-film element yields

NASA Astrophysics Data System (ADS)

Schalm, O.; Janssens, K.

2003-04-01

Quantitative analysis by means of electron probe X-ray microanalysis (EPXMA) of low Z materials such as silicate glasses can be hampered by the fact that ice or other contaminants build up on the Si(Li) detector beryllium window or (in the case of a windowless detector) on the Si(Li) crystal itself. These layers act as an additional absorber in front of the detector crystal, decreasing the detection efficiency at low energies (<5 keV). Since the layer thickness gradually changes with time, also the detector efficiency in the low energy region is not constant. Using the normal ZAF approach to quantification of EPXMA data is cumbersome in these conditions, because spectra from reference materials and from unknown samples must be acquired within a fairly short period of time in order to avoid the effect of the change in efficiency. To avoid this problem, an alternative approach to quantification of EPXMA data is proposed, following a philosophy often employed in quantitative analysis of X-ray fluorescence (XRF) and proton-induced X-ray emission (PIXE) data. This approach is based on the (experimental) determination of thin-film element yields, rather than starting from infinitely thick and single element calibration standards. These thin-film sensitivity coefficients can also be interpolated to allow quantification of elements for which no suitable standards are available. The change in detector efficiency can be monitored by collecting an X-ray spectrum of one multi-element glass standard. This information is used to adapt the previously determined thin-film sensitivity coefficients to the actual detector efficiency conditions valid on the day that the experiments were carried out. The main advantage of this method is that spectra collected from the standards and from the unknown samples should not be acquired within a short period of time. This new approach is evaluated for glass and metal matrices and is compared with a standard ZAF method.

Laser Plasma Soft X-ray Microscope with Wolter Mirrors for Observation of Biological Specimens in Air

NASA Astrophysics Data System (ADS)

Hoshino, Masato; Aoki, Sadao

2006-02-01

A laser plasma soft X-ray microscope with Wolter mirrors was developed so that specimens could be set in the atmosphere. Silicon nitride membranes 100 nm thick were used as vacuum-tight windows. Using relatively large windows (0.46× 0.46 mm2), an adequate working distance for samples, which was approximately 1.2 mm, was assured. The endurance of the vacuum-tight window was measured briefly. Dry biological cells could be observed with resolution better than 100 nm. A preliminary observation of wet biological cells was carried out using a wet environmental sample holder which was composed of only two sheets of silicon nitride membrane. An X-ray micrograph of wet red blood cells from a chicken was obtained without apparent effects of radiation damage. The properties of a vacuum-tight window and a wet sample holder are discussed.

[Technology Development for X-Ray Reflection for the Constellation-X Reflection Grating Spectrometer (RGS)

NASA Technical Reports Server (NTRS)

Schattenburg, Mark L.

2003-01-01

This Grant covers MIT support for the technology development of x-ray reflection gratings for the Constellation-X Reflection Grating Spectrometer (RGS). Since the start of the Grant MIT has extended its previously-developed patterning and super-smooth, blazed grating fabrication technology to ten-times smaller grating periods and ten-times larger blaze angles to demonstrate feasibility and performance in the off-plane grating geometry. In the past year we successfully developed several nanoimprint grating replication methods that achieved very high fidelity replication of master silicon gratings. Grating geometry on the nano and macro scales were faithfully replicated, demonstrating the viability of the process for manufacturing the thousands of gratings required for the RGS. We also successfully developed an improved metrology truss for holding test grating substrates during metrology. The flatness goal of grating substrates is under 500 nm. In the past, grating holders would cause non-repeatable distortion of >> 500 nm to the substrates due to friction and gravity sag. The new holder has a repeatability of under 50 nm which is adequate for the proposed RGS grating substrates.

In Situ Ramp Anneal X-ray Diffraction Study of Atomic Layer Deposited Ultrathin TaN and Ta 1-x Al x N y Films for Cu Diffusion Barrier Applications

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

Consiglio, S.; Dey, S.; Yu, K.

2016-01-01

Ultrathin TaN and Ta 1-xAl xN y films with x = 0.21 to 0.88 were deposited by atomic layer deposition (ALD) and evaluated for Cu diffusion barrier effectiveness compared to physical vapor deposition (PVD) grown TaN. Cu diffusion barrier effectiveness was investigated using in-situ ramp anneal synchrotron X-ray diffraction (XRD) on Cu/1.8 nm barrier/Si stacks. A Kissinger-like analysis was used to assess the kinetics of Cu 3Si formation and determine the effective activation energy (E a) for Cu silicidation. Compared to the stack with a PVD TaN barrier, the stacks with the ALD films exhibited a higher crystallization temperature (Tmore » c) for Cu silicidation. The Ea values of Cu 3Si formation for stacks with the ALD films were close to the reported value for grain boundary diffusion of Cu whereas the Ea of Cu 3Si formation for the stack with PVD TaN is closer to the reported value for lattice diffusion. For 3 nm films, grazing incidence in-plane XRD showed evidence of nanocrystallites in an amorphous matrix with broad peaks corresponding to high density cubic phase for the ALD grown films and lower density hexagonal phase for the PVD grown film further elucidating the difference in initial failure mechanisms due to differences in barrier crystallinity and associated phase.« less

Atomic moments in Mn 2CoAl thin films analyzed by X-ray magnetic circular dichroism

DOE PAGES

Jamer, M. E.; Assaf, B. A.; Sterbinsky, G. E.; ...

2014-12-05

Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn 2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. Results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value.

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

PubMed

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

2014-04-15

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

Synchrotron x-ray modification of nanoparticle superlattice formation

NASA Astrophysics Data System (ADS)

Lu, Chenguang; Akey, Austin J.; Herman, Irving P.

2012-09-01

The synchrotron x-ray radiation used to perform small angle x-ray scattering (SAXS) during the formation of three-dimensional nanoparticle superlattices by drop casting nanoparticle solutions affects the structure and the local crystalline order of the resulting films. The domain size decreases due to the real-time SAXS analysis during drying and more macroscopic changes are visible to the eye.

High Resolution Adjustable Mirror Control for X-ray Astronomy

NASA Astrophysics Data System (ADS)

Trolier-McKinstry, Susan

We propose to build and test thin film transistor control circuitry for a new highresolution adjustable X-ray mirror technology. This control circuitry will greatly simplify the wiring scheme to address individual actuator cells. The result will be a transformative improvement for the X-ray Surveyor mission concept: mathematical models, which fit the experimental data quite well, indicate that 0.5 arcsecond imaging is feasible through this technique utilizing thin slumped glass substrates with uncorrected angular resolution of order 5-10 arcseconds. In order to correct for figures errors in a telescope with several square meters of collecting area, millions of actuator cells must be set and held at specific voltages. It is clearly not feasible to do this via millions of wires, each one connected to an actuator. Instead, we propose to develop and test thin-film technology that operates on the same principle as megapixel computer screens. We will develop the technologies needed to build thin film piezoelectric actuators, controlled by thin film ZnO transistors, on flexible polyimide films, and to connect those films to the back surfaces of X-ray mirrors on thin glass substrates without deforming the surface. These technologies represent a promising avenue of the development of mirrors for the X-Ray Surveyor mission concept. Such a telescope will make possible detailed studies of a wide variety of astrophysical sources. One example is the Warm-Hot Intergalactic Medium (WHIM), which is thought to account for a large fraction of the normal matter in the universe but which has not been detected unambiguously to date. Another is the growth of supermassive black holes in the early universe. This proposal supports NASA's goals of technical advancement of technologies suitable for future missions, and training of graduate students.

Synchrotron x-ray study of a low roughness and high efficiency K 2 CsSb photocathode during film growth

DOE PAGES

Xie, Junqi; Demarteau, Marcel; Wagner, Robert; ...

2017-04-24

Reduction of roughness to the nm level is critical of achieving the ultimate performance from photocathodes used in high gradient fields. The thrust of this paper is to explore the evolution of roughness during sequential growth, and to show that deposition of multilayer structures consisting of very thin reacted layers results in an nm level smooth photocathode. Synchrotron x-ray methods were applied to study the multi-step growth process of a high efficiency K 2CsSb photocathode. We observed a transition point of the Sb film grown on Si at the film thickness of similar to 40 angstrom with the substrate temperaturemore » at 100 degrees C and the growth rate at 0.1 Å s -1. The final K 2CsSb photocathode exhibits a thickness of around five times that of the total deposited Sb film regardless of how the Sb film was grown. The film surface roughening process occurs first at the step when K diffuses into the crystalline Sb. Furthermore, the photocathode we obtained from the multi-step growth exhibits roughness in an order of magnitude lower than the normal sequential process. X-ray diffraction measurements show that the material goes through two structural changes of the crystalline phase during formation, from crystalline Sb to K 3Sb and finally to K 2CsSb.« less

Synchrotron x-ray study of a low roughness and high efficiency K 2 CsSb photocathode during film growth

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

Xie, Junqi; Demarteau, Marcel; Wagner, Robert

Reduction of roughness to the nm level is critical of achieving the ultimate performance from photocathodes used in high gradient fields. The thrust of this paper is to explore the evolution of roughness during sequential growth, and to show that deposition of multilayer structures consisting of very thin reacted layers results in an nm level smooth photocathode. Synchrotron x-ray methods were applied to study the multi-step growth process of a high efficiency K 2CsSb photocathode. We observed a transition point of the Sb film grown on Si at the film thickness of similar to 40 angstrom with the substrate temperaturemore » at 100 degrees C and the growth rate at 0.1 Å s -1. The final K 2CsSb photocathode exhibits a thickness of around five times that of the total deposited Sb film regardless of how the Sb film was grown. The film surface roughening process occurs first at the step when K diffuses into the crystalline Sb. Furthermore, the photocathode we obtained from the multi-step growth exhibits roughness in an order of magnitude lower than the normal sequential process. X-ray diffraction measurements show that the material goes through two structural changes of the crystalline phase during formation, from crystalline Sb to K 3Sb and finally to K 2CsSb.« less

An all-diamond X-ray position and flux monitor using nitrogen-incorporated ultra-nanocrystalline diamond contacts

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

Zou, Mengnan; Gaowei, Mengjia; Zhou, Tianyi

Diamond X-ray detectors with conducting nitrogen-incorporated ultra-nanocrystalline diamond (N-UNCD) films as electrodes were fabricated to measure X-ray beam flux and position. Structural characterization and functionality tests were performed for these devices. The N-UNCD films grown on unseeded diamond substrates were compared with N-UNCD films grown on a seeded silicon substrate. The feasibility of the N-UNCD films acting as electrodes for X-ray detectors was confirmed by the stable performance in a monochromatic X-ray beam. The fabrication process is able to change the surface status which may influence the signal uniformity under low bias, but this effect can be neglected under fullmore » collection bias.« less

Technical Note: Nanometric organic photovoltaic thin film detectors for dose monitoring in diagnostic x-ray imaging

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

Elshahat, Bassem; Gill, Hardeep Singh; Kumar, Jayant

2015-07-15

Purpose: To fabricate organic photovoltaic (OPV) cells with nanometric active layers sensitive to ionizing radiation and measure their dosimetric characteristics in clinical x-ray beams in the diagnostic tube potential range of 60–150 kVp. Methods: Experiments were designed to optimize the detector’s x-ray response and find the best parameter combination by changing the active layer thickness and the area of the electrode. The OPV cell consisted of poly (3-hexylthiophene-2,5-diyl): [6,6]-phenyl C{sub 61} butyric acid methyl ester photoactive donor and acceptor semiconducting organic materials sandwiched between an aluminum electrode as an anode and an indium tin oxide electrode as a cathode. Themore » authors measured the radiation-induced electric current at zero bias voltage in all fabricated OPV cells. Results: The net OPV current as a function of beam potential (kVp) was proportional to kVp{sup −0.5} when normalized to x-ray tube output, which varies with kVp. Of the tested configurations, the best combination of parameters was 270 nm active layer thicknesses with 0.7 cm{sup 2} electrode area, which provided the highest signal per electrode area. For this cell, the measured current ranged from approximately 0.7 to 2.4 nA/cm{sup 2} for 60–150 kVp, corresponding to about 0.09 nA–0.06 nA/mGy air kerma, respectively. When compared to commercial amorphous silicon thin film photovoltaic cells irradiated under the same conditions, this represents 2.5 times greater sensitivity. An additional 40% signal enhancement was observed when a 1 mm layer of plastic scintillator was attached to the cells’ beam-facing side. Conclusions: Since both OPVs can be produced as flexible devices and they do not require external bias voltage, they open the possibility for use as thin film in vivo detectors for dose monitoring in diagnostic x-ray imaging.« less

Flash X-ray with image enhancement applied to combustion events

NASA Astrophysics Data System (ADS)

White, K. J.; McCoy, D. G.

1983-10-01

Flow visualization of interior ballistic processes by use of X-rays has placed more stringent requirements on flash X-ray techniques. The problem of improving radiographic contrast of propellants in X-ray transparent chambers was studied by devising techniques for evaluating, measuring and reducing the effects of scattering from both the test object and structures in the test area. X-ray film and processing is reviewed and techniques for evaluating and calibrating these are outlined. Finally, after X-ray techniques were optimized, the application of image enhancement processing which can improve image quality is described. This technique was applied to X-ray studies of the combustion of very high burning rate (VHBR) propellants and stick propellant charges.

Development of an X-ray fluorescence holographic measurement system for protein crystals

NASA Astrophysics Data System (ADS)

Sato-Tomita, Ayana; Shibayama, Naoya; Happo, Naohisa; Kimura, Koji; Okabe, Takahiro; Matsushita, Tomohiro; Park, Sam-Yong; Sasaki, Yuji C.; Hayashi, Kouichi

2016-06-01

Experimental procedure and setup for obtaining X-ray fluorescence hologram of crystalline metalloprotein samples are described. Human hemoglobin, an α2β2 tetrameric metalloprotein containing the Fe(II) heme active-site in each chain, was chosen for this study because of its wealth of crystallographic data. A cold gas flow system was introduced to reduce X-ray radiation damage of protein crystals that are usually fragile and susceptible to damage. A χ-stage was installed to rotate the sample while avoiding intersection between the X-ray beam and the sample loop or holder, which is needed for supporting fragile protein crystals. Huge hemoglobin crystals (with a maximum size of 8 × 6 × 3 mm3) were prepared and used to keep the footprint of the incident X-ray beam smaller than the sample size during the entire course of the measurement with the incident angle of 0°-70°. Under these experimental and data acquisition conditions, we achieved the first observation of the X-ray fluorescence hologram pattern from the protein crystals with minimal radiation damage, opening up a new and potential method for investigating the stereochemistry of the metal active-sites in biomacromolecules.

Note: Setup for chemical atmospheric control during in situ grazing incidence X-ray scattering of printed thin films

DOE PAGES

Pröller, Stephan; Moseguí González, Daniel; Zhu, Chenhuii; ...

2017-06-01

In order to tailor the assembling of polymers and organic molecules, a deeper understanding of the kinetics involved in thin film production is necessary. While post-production characterization only provides insight on the final film structure, more sophisticated experimental setups are needed to probe the structure formation processes in situ during deposition. The drying kinetics of a deposited organic thin film strongly influences the assembling process on the nanometer scale. Lastly, this work presents an experimental setup that enables fine control of the atmosphere composition surrounding the sample during slot die coating, while simultaneously probing the film formation kinetics using inmore » situ grazing incidence X-ray scattering and spectroscopy.« less

Study of the gel films of Acetobacter Xylinum cellulose and its modified samples by {sup 1}H NMR cryoporometry and small-angle X-ray scattering

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

Babushkina, T. A.; Klimova, T. P.; Shtykova, E. V.

2010-03-15

Gel films of Acetobacter Xylinum cellulose and its modified samples have been investigated by 1H nuclear magnetic resonance (NMR) cryoporometry and small-angle X-ray scattering. The joint use of these two methods made it possible to characterize the sizes of aqueous pores in gel films and estimate the sizes of structural inhomogeneities before and after the sorption of polyvinylpyrrolidone and Se{sub 0} nanoparticles (stabilized by polyvinylpyrrolidone) into the films. According to small-angle X-ray scattering data, the sizes of inhomogeneities in a gel film change only slightly upon the sorption of polyvinylpyrrolidone and nanoparticles. The impregnated material is sorbed into water-filled cavitiesmore » that are present in the gel film. {sup 1}H NMR cryoporometry allowed us to reveal the details of changes in the sizes of small aqueous pores during modifications.« less

Low- Z polymer sample supports for fixed-target serial femtosecond X-ray crystallography

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

Feld, Geoffrey K.; Heymann, Michael; Benner, W. Henry

X-ray free-electron lasers (XFELs) offer a new avenue to the structural probing of complex materials, including biomolecules. Delivery of precious sample to the XFEL beam is a key consideration, as the sample of interest must be serially replaced after each destructive pulse. The fixed-target approach to sample delivery involves depositing samples on a thin-film support and subsequent serial introduction via a translating stage. Some classes of biological materials, including two-dimensional protein crystals, must be introduced on fixed-target supports, as they require a flat surface to prevent sample wrinkling. A series of wafer and transmission electron microscopy (TEM)-style grid supports constructedmore » of low- Z plastic have been custom-designed and produced. Aluminium TEM grid holders were engineered, capable of delivering up to 20 different conventional or plastic TEM grids using fixed-target stages available at the Linac Coherent Light Source (LCLS). As proof-of-principle, X-ray diffraction has been demonstrated from two-dimensional crystals of bacteriorhodopsin and three-dimensional crystals of anthrax toxin protective antigen mounted on these supports at the LCLS. In conclusion, the benefits and limitations of these low- Z fixed-target supports are discussed; it is the authors' belief that they represent a viable and efficient alternative to previously reported fixed-target supports for conducting diffraction studies with XFELs.« less

X-ray photoelectron spectroscopic study of the oxide film on an aluminum-tin alloy in 3.5% sodium chloride solution

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

Venugopal, A.; Selvam, P.; Raja, V.S.

1997-10-01

Oxide films on Al and an Al-Sn alloy were analyzed by x-ray photoelectron spectroscopy (XPS) after immersion in 3.5% sodium chloride (NaCl) solution. Results showed Sn exhibited both Sn{sup 2+} and Sn{sup 4+} oxidation stats in the oxide film. It was proposed that incorporation of these cations in the film would result in generation of more anionic and cationic vacancies in aluminum oxide (Al{sub 2}O{sub 3}), leading to active dissolution of Al.

Direct measurement of the propagation velocity of defects using coherent X-rays

DOE PAGES

Ulbrandt, Jeffrey G.; Rainville, Meliha G.; Wagenbach, Christa; ...

2016-03-28

The properties of artificially grown thin films are often strongly affected by the dynamic relationships between surface growth processes and subsurface structure. Coherent mixing of X-ray signals promises to provide an approach to better understand such processes. Here, we demonstrate the continuously variable mixing of surface and bulk scattering signals during realtime studies of sputter deposition of a-Si and a-WSi2 films by controlling the X-ray penetration and escape depths in coherent grazing-incidence small-angle X-ray scattering. Under conditions where the X-ray signal comes from both the growth surface and the thin film bulk, oscillations in temporal correlations arise from coherent interferencemore » between scattering from stationary bulk features and from the advancing surface. We also observe evidence that elongated bulk features propagate upwards at the same velocity as the surface. Moreover, a highly surface-sensitive mode is demonstrated that can access the surface dynamics independently of the subsurface structure.« less

Characterization of a-SiC:H films produced in a standard plasma enhanced chemical vapor deposition system for x-ray mask application

NASA Astrophysics Data System (ADS)

Jean, A.; Chaker, M.; Diawara, Y.; Leung, P. K.; Gat, E.; Mercier, P. P.; Pépin, H.; Gujrathi, S.; Ross, G. G.; Kieffer, J. C.

1992-10-01

Hydrogenated amorphous a-SixC1-x:H films with various compositions (0.2≤x≤0.8) were prepared by a radio frequency (rf 100 kHz) glow discharge decomposition of a silane and methane mixture diluted in argon. The deposition system used was a commercially available plasma enhanced chemical vapor deposition reactor allowing a high throughput (22 wafers of 4 in. diameter each run). The properties of the films such as thickness, density, and stress were investigated. The composition, including hydrogen content and Si/C ratio, and the structure of the films were systematically examined by means of several diagnostics including electron recoil detection, x-ray photoelectron spectroscopy, and infrared (IR) absorption analysis. Thickness and density of the films were dependent on the film composition, while the stress of the films was highly compressive (3×109-1×1010 dynes/cm2). Density was about 2.4 g/cm3 for nearly stoichiometric SiC films. The hydrogen content of the films was practically constant at 27 at. % over the whole investigated composition range. The IR analyses suggested that the structure of the silicon carbide films is inorganic-like over the whole range of compositions. From stoichiometric to carbon-rich films, the structure mainly consists of a tetrahedral network where silicon atoms are randomly replaced by carbon atoms and one hydrogen atom is bonded to silicon (SiH group). However, the presence of SiH2 groups and microvoids was observed in the structure of Si-rich silicon carbide films. Finally, the development of SiC membranes for x-ray lithography was presented including the control of film stress by means of rapid thermal annealing. Silicon carbide membranes of relatively high surface area (32×32 mm2) and showing high optical transparency (80%) were successfully fabricated.

Studies on RF sputtered (WO3)1-x (V2O5)x thin films for smart window applications

NASA Astrophysics Data System (ADS)

Meenakshi, M.; Sivakumar, R.; Perumal, P.; Sanjeeviraja, C.

2016-05-01

V2O5 doped WO3 targets for RF sputtering thin film deposition were prepared for various compositions. Thin films of (WO3)1-x (V2O5)x were deposited on to glass substrates using these targets. Structural characteristics of the prepared targets and thin films were studied using X-ray diffraction. Laser Raman studies were carried out on the thin films to confirm the compound formation.

SU-E-I-42: Measurement of X-Ray Beam Width and Geometric Efficiency in MDCT Using Radiochromic Films.

PubMed

Liillau, T; Liebmann, M; von Boetticher, H; Poppe, B

2012-06-01

The purpose of this work was to measure the x-ray beam width and geometric efficiency (GE) of a multi detector computed tomography scanner (MDCT) for different beam collimations using radiochromic films. In MDCT, the primary beam width extends the nominal beam collimation to irradiate the active detector elements uniformly (called 'over-beaming') which contributes to increased radiation dose to the patient compared to single detector CT. Therefore, the precise determination of the primary beam width and GE is of value for any CT dose calculation using Monte Carlo or analytical methods. Single axial dose profiles free in air were measured for 6 different beam collimations nT for a Siemens SOMATOM Sensation 64 Scanner with Gafchromic XR-QA2 films. The films were calibrated relative to the measured charge of a PTW semiflex ionization chamber (type: 31010) for a single rotation in the CT scanner at the largest available beam collimation of 28.8 mm. The beam energy for all measurements in this work was set to 120 kVp. For every measured dose profile and beam collimation the GEin-air and the full-width-at-half- maximum value (FWHM) as a value for the x-ray beam width was determined. Over-beaming factors FWHM / nT were calculated accordingly. For MDCT beam collimations from 7.2 (12×0.6 mm) to 28.8 (24×1.2 mm) the geometric efficiency was between 58 and 85 %. The over- beaming factor ranged from 1.43 to 1.11. For beam collimations of 1×5 mm and 1×10 mm the GE was 77 % and 84 % respectively. The over-beaming factors were close to 1, as expected. This work has shown that radiochromic films can be used for accurate x-ray beam width and geometric efficiency measurements due to their high spatial resolution. The measured free-in-air geometric efficiency and the over-beaming factor depend strongly on beam collimation. © 2012 American Association of Physicists in Medicine.

Surface morphology of vacuum-evaporated pentacene film on Si substrate studied by in situ grazing-incidence small-angle X-ray scattering: I. The initial stage of formation of pentacene film

NASA Astrophysics Data System (ADS)

Hirosawa, Ichiro; Watanabe, Takeshi; Koganezawa, Tomoyuki; Kikuchi, Mamoru; Yoshimoto, Noriyuki

2018-03-01

The progress of the surface morphology of a growing sub-monolayered pentacene film on a Si substrate was studied by in situ grazing-incidence small angle X-ray scattering (GISAXS). The observed GISAXS profiles did not show sizes of pentacene islands but mainly protuberances on the boundaries around pentacene film. Scattering of X-ray by residual pits in the pentacene film was also detected in the GISAXS profiles of an almost fully covered film. The average radius of pentacene protuberances increased from 13 to 24 nm as the coverage increased to 0.83 monolayer, and the most frequent radius was almost constant at approximately 9 nm. This result suggests that the population of larger protuberances increase with increasing lengths of boundaries of the pentacene film. It can also be considered that the detected protuberances were crystallites of pentacene, since the average size of protuberances was nearly equal to crystallite sizes of pentacene films. The almost constant characteristic distance of 610 nm and amplitudes of pair correlation functions at low coverages suggest that the growth of pentacene films obeyed the diffusion-limited aggregation (DLA) model, as previously reported. It is also considered that the sites of islands show a triangular distribution for small variations of estimated correlation distances.

Rapid crystallization of WS2 films assisted by a thin nickel layer: An in situ energy-dispersive X-ray diffraction study

NASA Astrophysics Data System (ADS)

Ellmer, K.; Seeger, S.; Mientus, R.

2006-08-01

By rapid thermal crystallization of an amorphous WS3+x film, deposited by reactive magnetron sputtering at temperatures below 150 °C, layer-type semiconducting tungsten disulfide films (WS2) were grown. The rapid crystallization was monitored in real-time by in situ energy-dispersive X-ray diffraction. The films crystallize very fast (>40 nm/s), provided that a thin nickel film acts as nucleation seeds. Experiments on different substrates and the onset of the crystallization only at a temperature between 600 and 700 °C points to the decisive role of seeds for the textured growth of WS2, most probably liquid NiSx drops. The rapidly crystallized WS2 films exhibit a pronounced (001) texture with the van der Waals planes oriented parallel to the surface, leading to photoactive layers with a high hole mobility of about 80 cm2/Vs making such films suitable as absorbers for thin film solar cells.

Monitoring X-Ray Emission from X-Ray Bursters

NASA Technical Reports Server (NTRS)

Halpern, Jules P.; Kaaret, Philip

1999-01-01

The scientific goal of this project was to monitor a selected sample of x-ray bursters using data from the All-Sky Monitor (ASM) on the Rossi X-Ray Timing Explorer together with data from the Burst and Transient Source Experiment (BATSE) on the Compton Gamma-Ray Observatory to study the long-term temporal evolution of these sources in the x-ray and hard x-ray bands. The project was closely related to "Long-Term Hard X-Ray Monitoring of X-Ray Bursters", NASA project NAG5-3891, and and "Hard x-ray emission of x-ray bursters", NASA project NAG5-4633, and shares publications in common with both of these. The project involved preparation of software for use in monitoring and then the actual monitoring itself. These efforts have lead to results directly from the ASM data and also from Target of Opportunity Observations (TOO) made with the Rossi X-Ray Timing Explorer based on detection of transient hard x-ray outbursts with the ASM and BATSE.

Electronic properties and bonding in Zr Hx thin films investigated by valence-band x-ray photoelectron spectroscopy

NASA Astrophysics Data System (ADS)

Magnuson, Martin; Schmidt, Susann; Hultman, Lars; Högberg, Hans

2017-11-01

The electronic structure and chemical bonding in reactively magnetron sputtered Zr Hx (x =0.15 , 0.30, 1.16) thin films with oxygen content as low as 0.2 at.% are investigated by 4d valence band, shallow 4p core-level, and 3d core-level x-ray photoelectron spectroscopy. With increasing hydrogen content, we observe significant reduction of the 4d valence states close to the Fermi level as a result of redistribution of intensity toward the H 1s-Zr 4d hybridization region at ˜6 eV below the Fermi level. For low hydrogen content (x =0.15 , 0.30), the films consist of a superposition of hexagonal closest-packed metal (α phase) and understoichiometric δ -Zr Hx (Ca F2 -type structure) phases, while for x =1.16 , the films form single-phase Zr Hx that largely resembles that of stoichiometric δ -Zr H2 phase. We show that the cubic δ -Zr Hx phase is metastable as thin film up to x =1.16 , while for higher H contents the structure is predicted to be tetragonally distorted. For the investigated Zr H1.16 film, we find chemical shifts of 0.68 and 0.51 eV toward higher binding energies for the Zr 4 p3 /2 and 3 d5 /2 peak positions, respectively. Compared to the Zr metal binding energies of 27.26 and 178.87 eV, this signifies a charge transfer from Zr to H atoms. The change in the electronic structure, spectral line shapes, and chemical shifts as a function of hydrogen content is discussed in relation to the charge transfer from Zr to H that affects the conductivity by charge redistribution in the valence band.

New insights into microstructural evolution of epitaxial Ni-Mn-Ga films on MgO (1 0 0) substrate by high-resolution X-ray diffraction and orientation imaging investigations

NASA Astrophysics Data System (ADS)

Sharma, Amit; Mohan, Sangeneni; Suwas, Satyam

2018-04-01

In this work, a detailed investigation has been performed on hetero-epitaxial growth and microstructural evolution in highly oriented Ni-Mn-Ga (1 0 0) films grown on MgO (1 0 0) substrate using high-resolution X-ray diffraction and orientation imaging microscopy. Mosaicity of the films has been analysed in terms of tilt angle, twist angle, lateral and vertical coherence length and threading dislocation densities by performing rocking curve measurements and reciprocal space mapping. Density of edge dislocations is found to be an order of magnitude higher than the density of screw dislocations, irrespective of film thickness. X-ray pole figure measurements have revealed an orientation relationship of ? || (1 0 0)MgO; ? || [0 0 1]MgO between the film and substrate. Microstructure predicted by X-ray diffraction is in agreement with that obtained from electron microscopy and atomic force microscopy. The evolution of microstructure in the film with increasing thickness has been explained vis-à-vis dislocation generation and growth mechanisms. Orientation imaging microscopy observations indicate evolutionary growth of film by overgrowth mechanism. Decrease in coercivity with film thickness has been explained as an interplay between stress field developed due to crystal defects and magnetic domain pinning due to surface roughness.

Oriented polyvinylidene fluoride–trifluoroethylene (P(VDF–TrFE)) films by Langmuir–Blodgett deposition: A synchrotron X-ray diffraction study

DOE PAGES

Lindemann, W. R.; Philiph, R. L.; Chan, D. W. W.; ...

2015-10-07

Langmuir–Blodgett films of polyvinylidene fluoride trifluoroethylene – P(VDF–TrFE)-copolymers possess substantially improved electrocaloric and pyroelectric properties, when compared with conventionally spin-cast films. In order to rationalize this, we prepared single-layered films of P(VDF–TrFE) (70:30) using both deposition techniques. Grazing incidence wide-angle X-ray scattering (GIWAXS), reveals that Langmuir–Blodgett deposited films have a higher concentration of the ferroelectric β-phase crystals, and that these films are highly oriented with respect to the substrate. Based on these observations, we suggest alternative means of deposition, which may substantially enhance the electrocaloric effect in P(VDF–TrFE) films. As a result, this development has significant implications for the potentialmore » use of P(VDF–TrFE) in solid-state refrigeration.« less

X-ray reflectometry and simulation of the parameters of SiC epitaxial films on Si(111), grown by the atomic substitution method

NASA Astrophysics Data System (ADS)

Kukushkin, S. A.; Nussupov, K. Kh.; Osipov, A. V.; Beisenkhanov, N. B.; Bakranova, D. I.

2017-05-01

The structure and composition of SiC nanolayers are comprehensively studied by X-ray reflectometry, IR-spectroscopy, and atomic-force microscopy (AFM) methods for the first time. SiC films were synthesized by the new method of topochemical substitution of substrate atoms at various temperatures and pressure of CO active gas on the surface of high-resistivity low-dislocation single-crystal n-type silicon (111). Based on an analysis and generalization of experimental data obtained using X-ray reflectometry, IR spectroscopy, and AFM methods, a structural model of SiC films on Si was proposed. According to this model, silicon carbide film consists of a number of layers parallel to the substrate, reminiscent of a layer cake. The composition and thickness of each layer entering the film structure is experimentally determined. It was found that all samples contain superstoichiometric carbon; however, its structure is significantly different for the samples synthesized at temperatures of 1250 and 1330°C, respectively. In the former case, the film surface is saturated with silicon vacancies and carbon in the structurally loose form reminiscent of HOPG carbon. In the films grown at 1330°C, carbon is in a dense structure with a close-to-diamond density.

Effects of the carrier concentration on polarity determination in Ga-doped ZnO films by hard x-ray photoelectron spectroscopy

NASA Astrophysics Data System (ADS)

Song, Huaping; Makino, Hisao; Kobata, Masaaki; Nomoto, Junichi; Kobayashi, Keisuke; Yamamoto, Tetsuya

2018-03-01

Core level (CL) and valence band (VB) spectra of heavily Ga-doped ZnO (GZO) films with carrier concentrations (Ne) ranging from 1.8 × 1020 to 1.0 × 1021 cm-3 were measured by high-resolution Al Kα (hν = 1486.6 eV) x-ray photoelectron spectroscopy (XPS) and Cr Kα (hν = 5414.7 eV) hard x-ray photoelectron spectroscopy (HAXPES). The CL spectra of the GZO films measured by XPS had little dependence on Ne. In contrast, clear differences in asymmetric broadening were observed in the HAXPES spectra owing to the large probing depth. The asymmetry in the Zn 2p3/2 and O 1s HAXPES spectra is mainly attributed to the energy loss of the conduction electron plasmon caused by the high Ne of the GZO films. Similar asymmetry was also observed in the VB spectra of these GZO films. It was found that such asymmetry plays a crucial role in the determination of crystal polarity. With increasing Ne, the intensity of the sub-peak at a binding energy Eb of about 5 eV in the VB spectrum decreased and the sub-peak became indistinguishable. We clarified the limitation of the criterion using the sub-peak and proposed an alternative method for polarity determination.

Sputtered carbon as a corrosion barrier for x-ray detector windows

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

Rowley, Joseph; Pei, Lei; Davis, Robert C., E-mail: davis@byu.edu

Sputtered amorphous carbon thin films were explored as corrosion resistant coatings on aluminum thin films to be incorporated into x-ray detector windows. The requirements for this application include high corrosion resistance, low intrinsic stress, high strains at failure, and high x-ray transmission. Low temperature sputtering was used because of its compatibility with the rest of the window fabrication process. Corrosion resistance was tested by exposure of carbon coated and uncoated Al thin films to humidity. Substrate curvature and bulge testing measurements were used to determine intrinsic stress and ultimate strain at failure. The composition and bonding of the carbon filmsmore » were further characterized by electron energy loss spectroscopy, Raman spectroscopy, and carbon, hydrogen, and nitrogen elemental analyses. Samples had low compressive stress (down to.08 GPa), a high strain at failure (3%), and a low fraction of sp{sup 3} carbon–carbon bonds (less than 5%). The high breaking strain and excellent x-ray transmission of these sputtered carbon films indicate that they will work well as corrosion barriers in this application.« less

Research in Solar Physics: Analysis of Skylab/ATM S-056 X-Ray Data

NASA Technical Reports Server (NTRS)

Henze, W., Jr.

1977-01-01

Data obtained by the X-ray event analyzer are described as well as methods used for film calibration. Topics discussed include analyses of the 15 June 1973 flare, oscillations in the solar soft X-ray flux, and deconvolution of X-ray images of the 5 September 1973 flare.

Coherent X-ray Scattering from Liquid-Air Interfaces

NASA Astrophysics Data System (ADS)

Shpyrko, Oleg

Advances in synchrotron x-ray scattering techniques allow studies of structure and dynamics of liquid surfaces with unprecedented resolution. I will review x-ray scattering measurements of thermally excited capillary fluctuations in liquids, thin polymer liquid films and polymer surfaces in confined geometry. X-ray Diffuse scattering profile due to Debye-Waller like roughening of the surface allows to probe the distribution of capillary fluctuations over a wide range of length scales, while using X-ray Photon Correlation Spectroscopy (XPCS) one is able to directly couple to nanoscale dynamics of these surface fluctuations, over a wide range of temporal and spacial scales. I will also discuss recent XPCS measurements of lateral diffusion dynamics in Langmuir monolayers assembled at the liquid-air interface. This research was supported by NSF CAREER Grant 0956131.

Characterization of ion beam sputtered deposited W/Si multilayers by grazing incidence x-ray diffraction and x-ray reflectivity technique

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

Dhawan, Rajnish, E-mail: rajnish@rrcat.gov.in; Rai, Sanjay

2016-05-23

W/Si multilayers four samples have been deposited on silicon substrate using ion beam sputtering system. Thickness of tungsten (W) varies from around 10 Å to 40 Å while the silicon (Si) thickness remains constant at around 30 Å in multilayers [W-Si]{sub x4}. The samples have been characterized by grazing incidence X-ray diffraction (GIXRD) and X-ray reflectivity technique (XRR). GIXRD study shows the crystalline behaviour of W/Si multilayer by varying W thickness and it is found that above 20 Å the W film transform from amorphous to crystalline phase and X-ray reflectivity data shows that the roughnesses of W increases onmore » increasing the W thicknesses in W/Si multilayers.« less

Trans-oral miniature X-ray radiation delivery system with endoscopic optical feedback.

PubMed

Boese, Axel; Johnson, Fredrick; Ebert, Till; Mahmoud-Pashazadeh, Ali; Arens, Christoph; Friebe, Michael

2017-11-01

Surgery, chemo- and/or external radiation therapy are the standard therapy options for the treatment of laryngeal cancer. Trans-oral access for the surgery reduces traumata and hospitalization time. A new trend in treatment is organ-preserving surgery. To avoid regrowth of cancer, this type of surgery can be combined with radiation therapy. Since external radiation includes healthy tissue surrounding the cancerous zone, a local and direct intraoral radiation delivery would be beneficial. A general concept for a trans-oral radiation system was designed, based on clinical need identification with a medical user. A miniaturized X-ray tube was used as the radiation source for the intraoperative radiation delivery. To reduce dose distribution on healthy areas, the X-ray source was collimated by a newly designed adjustable shielding system as part of the housing. For direct optical visualization of the radiation zone, a miniature flexible endoscope was integrated into the system. The endoscopic light cone and the field of view were aligned with the zone of the collimated radiation. The intraoperative radiation system was mounted on a semi-automatic medical holder that was combined with a frontal actuator for rotational and translational movement using piezoelectric motors to provide precise placement. The entire technical set-up was tested in a simulated environment. The shielding of the X-ray source was verified by performing conventional detector-based dose measurements. The delivered dose was estimated by an ionization chamber. The adjustment of the radiation zone was performed by a manual controlling mechanism integrated into the hand piece of the device. An endoscopic fibre was also added to offer visualization and illumination of the radiation zone. The combination of the radiation system with the semi-automatic holder and actuator offered precise and stable positioning of the device in range of micrometres and will allow for future combination with a radiation

Soft x-ray speckle from rough surfaces

NASA Astrophysics Data System (ADS)

Porter, Matthew Stanton

Dynamic light scattering has been of great use in determining diffusion times for polymer solutions. At the same time, polymer thin films are becoming of increasing importance, especially in the semiconductor industry where they are used as photoresists and interlevel dielectrics. As the dimensions of these devices decrease we will reach a point where lasers will no longer be able to probe the length scales of interest. Current laser wavelengths limit the size of observable diffusion lengths to 180-700 nm. This dissertation will discuss attempts at pushing dynamic fight scattering experiments into the soft x-ray region so that we can examine fluctuations in polymer thin films on the molecular length scale. The dissertation explores the possibility of carrying out a dynamic light scattering experiment in the soft x-ray regime. A detailed account of how to meet the basic requirements for a coherent scattering experiment in the soft x-ray regime win be given. In addition, a complete description of the chamber design will be discussed. We used our custom designed scattering chamber to collect reproducible coherent soft x-ray scattering data from etched silicon wafers and from polystyrene coated silicon wafers. The data from the silicon wafers followed the statistics for a well-developed speckle pattern while the data from the polystyrene films exhibited Poisson statistics. We used the data from both the etched wafers and the polystyrene coated wafers to place a lower limit of ~20 Å on the RMS surface roughness of samples which will produce well defined speckle patterns for the current detector setup. Future experiments which use the criteria set forth in this dissertation have the opportunity to be even more successful than this dissertation project.

Angular distribution of fusion products and x rays emitted by a small dense plasma focus machine

NASA Astrophysics Data System (ADS)

Castillo, F.; Herrera, J. J. E.; Gamboa, Isabel; Rangel, J.; Golzarri, J. I.; Espinosa, G.

2007-01-01

Time integrated measurements of the angular distributions of fusion products and x rays in a small dense plasma focus machine are made inside the discharge chamber, using passive detectors. The machine is operated at 37kV with a stored energy of 4.8kJ and a deuterium filling pressure of 2.75torr. Distributions of protons and neutrons are measured with CR-39 Lantrack® nuclear track detectors, on 1.8×0.9cm2 chips, 500μm thick. A set of detectors was placed on a semicircular Teflon® holder, 13cm away from the plasma column, and covered with 15μm Al filters, thus eliminating tritium and helium-3 ions, but not protons and neutrons. A second set was placed on the opposite side of the holder, eliminating protons. The angular distribution of x rays is also studied within the chamber with TLD-200 dosimeters. While the neutron angular distributions can be fitted by Gaussian curves mounted on constant pedestals and the proton distributions are strongly peaked, falling rapidly after ±40°, the x-ray distributions show two maxima around the axis, presumably as a result of the collision of a collimated electron beam against the inner electrode, along the axis.

High-resolution x-ray diffraction and transmission electron microscopy of multiferroic BiFeO3 films

NASA Astrophysics Data System (ADS)

Qi, Xiaoding; Wei, Ming; Lin, Yuan; Jia, Quanxi; Zhi, Dan; Dho, Joonghoe; Blamire, Mark G.; MacManus-Driscoll, Judith L.

2005-02-01

High-resolution x-ray diffraction and transmission electron microscopy (TEM) have been used to study BiFeO3 thin films grown on the bare and SrRuO3 buffered (001) SrTiO3 substrates. Reciprocal space mapping (RSM) around (002) and (103) reflections revealed that BFO films with a thickness of about 200 nm were almost fully relaxed and had a rhombohedral structure. Cross-sectional, high-resolution TEM showed that the films started to relax at a very early stage of growth, which was consistent with the RSM results. A thin intermediate layer of about 2 nm was observed at the interface, which had a smaller lattice than the overgrown film. Twist distortions about the c axis to release the shear strain introduced by the growth of rhombic (001) BiFeO3 on cubic (001) SrTiO3 were also observed. The results indicate that a strained, coherent BiFeO3 film on (001) SrTiO3 is very difficult to maintain and (111) STO substrates are preferable.

Energy dependent calibration of XR-QA2 radiochromic film with monochromatic and polychromatic x-ray beams

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

Di Lillo, F.; Mettivier, G., E-mail: mettivier@na.infn.it; Sarno, A.

2016-01-15

Purpose: This work investigates the energy response and dose-response curve determinations for XR-QA2 radiochromic film dosimetry system used for synchrotron radiation work and for quality assurance in diagnostic radiology, in the range of effective energies 18–46.5 keV. Methods: Pieces of XR-QA2 films were irradiated, in a plane transverse to the beam axis, with a monochromatic beam of energy in the range 18–40 keV at the ELETTRA synchrotron radiation facility (Trieste, Italy) and with a polychromatic beam from a laboratory x-ray tube operated at 80, 100, and 120 kV. The film calibration curve was expressed as air kerma (measured free-in-air withmore » an ionization chamber) versus the net optical reflectance change (netΔR) derived from the red channel of the RGB scanned film image. Four functional relationships (rational, linear exponential, power, and logarithm) were tested to evaluate the best curve for fitting the calibration data. The adequacy of the various fitting functions was tested by using the uncertainty analysis and by assessing the average of the absolute air kerma error calculated as the difference between calculated and delivered air kerma. The sensitivity of the film was evaluated as the ratio of the change in net reflectance to the corresponding air kerma. Results: The sensitivity of XR-QA2 films increased in the energy range 18–39 keV, with a maximum variation of about 170%, and decreased in the energy range 38–46.5 keV. The present results confirmed and extended previous findings by this and other groups, as regards the dose response of the radiochromic film XR-QA2 to monochromatic and polychromatic x-ray beams, respectively. Conclusions: The XR-QA2 radiochromic film response showed a strong dependence on beam energy for both monochromatic and polychromatic beams in the range of half value layer values from 0.55 to 6.1 mm Al and corresponding effective energies from 18 to 46.5 keV. In this range, the film response varied by 170

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

DOE PAGES

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

2017-02-20

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

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

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

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

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

In-plane x-ray diffraction for characterization of monolayer and few-layer transition metal dichalcogenide films

NASA Astrophysics Data System (ADS)

Chubarov, Mikhail; Choudhury, Tanushree H.; Zhang, Xiaotian; Redwing, Joan M.

2018-02-01

There is significant interest in the growth of single crystal monolayer and few-layer films of transition metal dichalcogenides (TMD) and other 2D materials for scientific exploration and potential applications in optics, electronics, sensing, catalysis and others. The characterization of these materials is crucial in determining the properties and hence the applications. The ultra-thin nature of 2D layers presents a challenge to the use of x-ray diffraction (XRD) analysis with conventional Bragg-Brentano geometry in analyzing the crystallinity and epitaxial orientation of 2D films. To circumvent this problem, we demonstrate the use of in-plane XRD employing lab scale equipment which uses a standard Cu x-ray tube for the analysis of the crystallinity of TMD monolayer and few-layer films. The applicability of this technique is demonstrated in several examples for WSe2 and WS2 films grown by chemical vapor deposition on single crystal substrates. In-plane XRD was used to determine the epitaxial relation of WSe2 grown on c-plane sapphire and on SiC with an epitaxial graphene interlayer. The evolution of the crystal structure orientation of WS2 films on sapphire as a function of growth temperature was also examined. Finally, the epitaxial relation of a WS2/WSe2 vertical heterostructure deposited on sapphire substrate was determined. We observed that WSe2 grows epitaxially on both substrates employed in this work under all conditions studied while WS2 exhibits various preferred orientations on sapphire substrate which are temperature dependent. In contrast to the sapphire substrate, WS2 deposited on WSe2 exhibits only one preferred orientation which may provide a route to better control the orientation and crystal quality of WS2. In the case of epitaxial graphene on SiC, no graphene-related peaks were observed in in-plane XRD while its presence was confirmed using Raman spectroscopy. This demonstrates the limitation of the in-plane XRD technique for characterizing low

X-ray filter for x-ray powder diffraction

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

Sinsheimer, John Jay; Conley, Raymond P.; Bouet, Nathalie C. D.

Technologies are described for apparatus, methods and systems effective for filtering. The filters may comprise a first plate. The first plate may include an x-ray absorbing material and walls defining first slits. The first slits may include arc shaped openings through the first plate. The walls of the first plate may be configured to absorb at least some of first x-rays when the first x-rays are incident on the x-ray absorbing material, and to output second x-rays. The filters may comprise a second plate spaced from the first plate. The second plate may include the x-ray absorbing material and wallsmore » defining second slits. The second slits may include arc shaped openings through the second plate. The walls of the second plate may be configured to absorb at least some of second x-rays and to output third x-rays.« less

A New Development in the Method of Measurement of Reciprocity-Law Failure and Its Application to Screen/Green-Sensitive X-Ray Film Systems

NASA Astrophysics Data System (ADS)

Fujita, Hiroshi; Uchida, Suguru

1981-01-01

Since it has been confirmed by experiment that the intensity of X-rays varies approximately as the focus-film distance (FFD) to the minus 2.12th power, the X-ray intensity can be changed by varying the FFD. It is shown in this paper that two types of reciprocity failure curve, density vs. exposure time for constant exposure and relative exposure vs. exposure time for constant density, can easily be obtained from several time-scale characteristic curves taken experimentally for several FFD’s in the rare-earth screen-film systems used. Only low-intensity reciprocity failure is present for exposure times of more than about 0.1 sec for one film, but both low-intensity and high-intensity reciprocity failures occur in the other one. The effects of reciprocity failure on the H & D curves can be seen in the shape of the curves and the relative speed.

Apparatus for X-ray diffraction microscopy and tomography of cryo specimens

DOE PAGES

Beetz, T.; Howells, M. R.; Jacobsen, C.; ...

2005-03-14

An apparatus for diffraction microscopy of biological and materials science specimens is described. In this system, a coherent soft X-ray beam is selected with a pinhole, and the illuminated specimen is followed by an adjustable beamstop and CCD camera to record diffraction data from non-crystalline specimens. In addition, a Fresnel zone plate can be inserted to allow for direct imaging. The system makes use of a cryogenic specimen holder with cryotransfer capabilities to allow frozen hydrated specimens to be loaded. The specimen can be tilted over a range of ± 80 ° degrees for three-dimensional imaging; this is done bymore » computer-controlled motors, enabling automated alignment of the specimen through a tilt series. The system is now in use for experiments in soft X-ray diffraction microscopy.« less

Ultrashort x-ray backlighters and applications

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

Umstadter, D., University of Michigan

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

Porous plug phase separator and superfluid film flow suppression system for the soft x-ray spectrometer onboard ASTRO-H

NASA Astrophysics Data System (ADS)

Ezoe, Yuichiro; Ishikawa, Kumi; Mitsuishi, Ikuyuki; Ohashi, Takaya; Mitsuda, Kazuhisa; Fujimoto, Ryuichi; Murakami, Masahide; Kanao, Kenichi; Yoshida, Seiji; Tsunematsu, Shoji; DiPirro, Michael; Shirron, Peter

2016-07-01

Suppression of super fluid helium flow is critical for the Soft X-ray Spectrometer onboard ASTRO-H (Hitomi). In nominal operation, a small helium gas flow of 30 μg/s must be safely vented and a super fluid film flow must be sufficiently small <2 μg/s. To achieve a life time of the liquid helium, a porous plug phase separator and a film flow suppression system composed of an orifice, a heat exchanger, and knife edge devices are employed. In this paper, design, on-ground testing results and in-orbit performance of the porous plug and the film flow suppression system are described.

Picosecond x-ray diagnostics for third and fourth generation synchrotron sources

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

DeCamp, Matthew

2016-03-30

In the DOE-EPSCoR State/National Laboratory partnership grant ``Picosecond x-ray diagnostics for third and fourth generation synchrotron sources'' Dr. DeCamp set forth a partnership between the University of Delaware and Argonne National Laboratory. This proposal aimed to design and implement a series of experiments utilizing, or improving upon, existing time-domain hard x-ray spectroscopies at a third generation synchrotron source. Specifically, the PI put forth three experimental projects to be explored in the grant cycle: 1) implementing a picosecond ``x-ray Bragg switch'' using a laser excited nano-structured metallic film, 2) designing a robust x-ray optical delay stage for x-ray pump-probe studies atmore » a hard x-ray synchrotron source, and 3) building/installing a laser based x-ray source at the Advanced Photon Source for two-color x-ray pump-probe studies.« less

Proton-induces and x-ray induced fluorescence analysis of scoliotic tissue

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

Panessa-Warren, B J; Kraner, H W; Jones, K W

1980-02-01

Adolescent idiopathic scoliosis is characterized by a curvature or assymetry of the spine which may become progressively more severe, with clinical symptoms appearing just prior to, or during, puberty. The incidence for scoliosis in the age group from 12 to 14 years of age has been reported as high as 8 to 10%, with more than 80% of the cases occurring in females. Although pathologic changes exist in muscles from both sides of the spinal curvature, and no statistically significant side differences have been reported, morphologic changes suggest that the concanve side is the most affected. This paper reports ourmore » preliminary data on the elemental composition of individual muscle fibers derived from convex, concave and gluteal scoliotic muscle, and erythrocytes from scoliotic and normal patients, analyzed by proton induced x-ray emission (PIXE) and x-ray fluorescence spectroscopy (XRF). A new type of specimen holder was designed for this study which offers low x-ray background, minimal absorption and maintenance of a moist environment around the specimen.« less

Observation of the X-Ray Magneto-Optical Voigt Effect

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

Mertins, H.-Ch.; Oppeneer, P. M.; Kunes, J.

2001-07-23

The existence of the x-ray magneto-optical Voigt effect is demonstrated. By means of polarization analysis the Voigt rotation and ellipticity of linearly polarized synchrotron radiation are measured at the Co L{sub 3} edge upon transmission through an amorphous Co film. The observed x-ray Voigt rotation is about 7.5{sup o}/{mu}m . On the basis of ab initio calculations it is shown that the x-ray Voigt effect follows sensitively the amount of spin polarization of the 2p core states. Therefore it provides a unique measure of the spin splitting of the core states.

Structural and magnetic properties of sol-gel Co2xNi0.5-x Zn0.5-xFe2O4 thin films

NASA Astrophysics Data System (ADS)

Rebrov, Evgeny V.; Gao, Pengzhao; Verhoeven, Tiny M. W. G. M.; Schouten, Jaap C.; Kleismit, Richard; Turgut, Zafer; Kozlowski, Gregory

2011-03-01

Nanocrystalline Co2xNi0.5-xZn0.5-xFe2O4 (x=0-0.5) thin films have been synthesized with various grain sizes by a sol-gel method on polycrystalline silicon substrates. The morphology as well as magnetic and microwave absorption properties of the films calcined at 1073 K were studied using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. All films were uniform without microcracks. The Co content in the Co-Ni-Zn films resulted in a grain size ranging from 15 to 32 nm while it ranged from 33 to 49 nm in the corresponding powders. Saturation and remnant magnetization increased with increase in grain size, while coercivity demonstrated a drop due to multidomain behavior of crystallites for a given value of x. Saturation magnetization increased and remnant magnetization had a maximum as a function of grain size independent of x. In turn, coercivity increased with x independent of grain size. Complex permittivity of the Co-Ni-Zn ferrite films was measured in the frequency range 2-15 GHz. The highest hysteretic heating rate in the temperature range 315-355 K was observed in CoFe2O4. The maximum absorption band shifted from 13 to 11 GHz as cobalt content increased from x=0.1 to 0.2.

Refractive Optics for Hard X-ray Transmission Microscopy

NASA Astrophysics Data System (ADS)

Simon, M.; Ahrens, G.; Last, A.; Mohr, J.; Nazmov, V.; Reznikova, E.; Voigt, A.

2011-09-01

For hard x-ray transmission microscopy at photon energies higher than 15 keV we design refractive condenser and imaging elements to be used with synchrotron light sources as well as with x-ray tube sources. The condenser lenses are optimized for low x-ray attenuation—resulting in apertures greater than 1 mm—and homogeneous intensity distribution on the detector plane, whereas the imaging enables high-resolution (<100 nm) full-field imaging. To obtain high image quality at reasonable exposure times, custom-tailored matched pairs of condenser and imaging lenses are being developed. The imaging lenses (compound refractive lenses, CRLs) are made of SU-8 negative resist by deep x-ray lithography. SU-8 shows high radiation stability. The fabrication technique enables high-quality lens structures regarding surface roughness and arrangement precision with arbitrary 2D geometry. To provide point foci, crossed pairs of lenses are used. Condenser lenses have been made utilizing deep x-ray lithographic patterning of thick SU-8 layers, too, whereas in this case, the aperture is limited due to process restrictions. Thus, in terms of large apertures, condenser lenses made of structured and rolled polyimide film are more attractive. Both condenser types, x-ray mosaic lenses and rolled x-ray prism lenses (RXPLs), are considered to be implemented into a microscope setup. The x-ray optical elements mentioned above are characterized with synchrotron radiation and x-ray laboratory sources, respectively.

Technology Requirements for a Square Meter, Arcsecond Resolution Telescope for X-Rays: The SMART-X Mission

NASA Technical Reports Server (NTRS)

Schwartz, Daniel A.; Allured, Ryan; Bookbinder, Jay A.; Cotroneo, Vincenzo; Forman, William R.; Freeman, Mark D.; McMuldroch, Stuart; Reid, Paul B.; Tananbaum, Harvey; Vikhlinin, Alexey A.;

Perpendicular magnetic anisotropy in amorphous NdxCo1 -x thin films studied by x-ray magnetic circular dichroism

NASA Astrophysics Data System (ADS)

Cid, R.; Alameda, J. M.; Valvidares, S. M.; Cezar, J. C.; Bencok, P.; Brookes, N. B.; Díaz, J.

2017-06-01

The origin of perpendicular magnetic anisotropy (PMA) in amorphous NdxCo1 -x thin films is investigated using x-ray magnetic circular dichroism (XMCD) spectroscopy at the Co L2 ,3 and Nd M4 ,5 edges. The magnetic orbital and spin moments of the 3 d cobalt and 4 f neodymium electrons were measured as a function of the magnetic field orientation, neodymium concentration, and temperature. In all the studied samples, the magnetic anisotropy of the neodymium subnetwork is always oriented perpendicular to the plane, whereas the anisotropy of the orbital moment of cobalt is in the basal plane. The ratio Lz/Sz of the neodymium 4 f orbitals changes with the sample orientation angle, being higher and closer to the atomic expected value at normal orientation and smaller at grazing angles. This result is well explained by assuming that the 4 f orbital is distorted by the effect of an anisotropic crystal field when it is magnetized along its hard axis, clearly indicating that the 4 f states are not rotationally invariant. The magnetic anisotropy energy associated to the neodymium subnetwork should be proportional to this distortion, which we demonstrate is accessible by applying the XMCD sum rules for the spin and intensity at the Nd M4 ,5 edges. The analysis unveils a significant portion of neodymium atoms magnetically uncoupled to cobalt, i.e., paramagnetic, confirming the inhomogeneity of the films and the presence of a highly disordered neodymium rich phase already detected by extended x-ray-absorption fine structure (EXAFS) spectroscopy. The presence of these inhomogeneities is inherent to the evaporation preparation method when the chosen concentration in the alloy is far from its eutectic concentrations. An interesting consequence of the particular way in which cobalt and neodymium segregates in this system is the enhancement of the cobalt spin moment which reaches 1.95 μB in the sample with the largest segregation.

Optical Density Analysis of X-Rays Utilizing Calibration Tooling to Estimate Thickness of Parts

NASA Technical Reports Server (NTRS)

Grau, David

2012-01-01

This process is designed to estimate the thickness change of a material through data analysis of a digitized version of an x-ray (or a digital x-ray) containing the material (with the thickness in question) and various tooling. Using this process, it is possible to estimate a material's thickness change in a region of the material or part that is thinner than the rest of the reference thickness. However, that same principle process can be used to determine the thickness change of material using a thinner region to determine thickening, or it can be used to develop contour plots of an entire part. Proper tooling must be used. An x-ray film with an S-shaped characteristic curve or a digital x-ray device with a product resulting in like characteristics is necessary. If a film exists with linear characteristics, this type of film would be ideal; however, at the time of this reporting, no such film has been known. Machined components (with known fractional thicknesses) of a like material (similar density) to that of the material to be measured are necessary. The machined components should have machined through-holes. For ease of use and better accuracy, the throughholes should be a size larger than 0.125 in. (.3 mm). Standard components for this use are known as penetrameters or image quality indicators. Also needed is standard x-ray equipment, if film is used in place of digital equipment, or x-ray digitization equipment with proven conversion properties. Typical x-ray digitization equipment is commonly used in the medical industry, and creates digital images of x-rays in DICOM format. It is recommended to scan the image in a 16-bit format. However, 12-bit and 8-bit resolutions are acceptable. Finally, x-ray analysis software that allows accurate digital image density calculations, such as Image-J freeware, is needed. The actual procedure requires the test article to be placed on the raw x-ray, ensuring the region of interest is aligned for perpendicular x-ray exposure

Influence of Oxygen Content in Oriented LaCoO3-δ Thin Films: Probed by X-ray diffraction and Raman Spectroscopy

NASA Astrophysics Data System (ADS)

Mishra, D. K.; Ahlawat, Anju; Sathe, V. G.

2011-07-01

Nonstoichiometric oriented thin films of LaCoO3-δ of equal thickness and varying oxygen content has been deposited on STO (001) substrate by pulsed laser deposition. X-ray diffraction results show that all films are single phase and c-axis oriented in the (001) direction with in plane tensile strain. In these films strain reduces with increasing oxygen content and Raman study also support this result. Low temperature Raman study shows no change in spin state of Co3+ in temperature range from 300 K to down to 80 K.

Improved control of medical x-ray film exposure

NASA Technical Reports Server (NTRS)

Berdahl, C. M.

1978-01-01

Exposure sensing system for light-intensified motion-picture X-ray system uses aperture or adjustable diaphragm to sample light from image region of interest. Approach, along with approximate optics, can optimize exposure sensitivity.

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.

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

PubMed

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.

Imaging Nanometer Phase Coexistence at Defects During the Insulator-Metal Phase Transformation in VO2 Thin Films by Resonant Soft X-ray Holography.

PubMed

Vidas, Luciana; Günther, Christian M; Miller, Timothy A; Pfau, Bastian; Perez-Salinas, Daniel; Martínez, Elías; Schneider, Michael; Gührs, Erik; Gargiani, Pierluigi; Valvidares, Manuel; Marvel, Robert E; Hallman, Kent A; Haglund, Richard F; Eisebitt, Stefan; Wall, Simon

2018-05-18

We use resonant soft X-ray holography to image the insulator-metal phase transition in vanadium dioxide with element and polarization specificity and nanometer spatial resolution. We observe that nanoscale inhomogeneity in the film results in spatial-dependent transition pathways between the insulating and metallic states. Additional nanoscale phases form in the vicinity of defects which are not apparent in the initial or final states of the system, which would be missed in area-integrated X-ray absorption measurements. These intermediate phases are vital to understand the phase transition in VO 2 , and our results demonstrate how resonant imaging can be used to understand the electronic properties of phase-separated correlated materials obtained by X-ray absorption.

Giant Faraday rotation in Bi(x)Ce(3-x)Fe5O12 epitaxial garnet films.

PubMed

Chandra Sekhar, M; Singh, Mahi R; Basu, Shantanu; Pinnepalli, Sai

2012-04-23

Thin films of Bi(x)Ce(3-x)Fe(5)O(12) with x = 0.7 and 0.8 compositions were prepared by using pulsed laser deposition. We investigated the effects of processing parameters used to fabricate these films by measuring various physical properties such as X-ray diffraction, transmittance, magnetization and Faraday rotation. In this study, we propose a phase diagram which provides a suitable window for the deposition of Bi(x)Ce(3-x)Fe(5)O(12) epitaxial films. We have also observed a giant Faraday rotation of 1-1.10 degree/µm in our optimized films. The measured Faraday rotation value is 1.6 and 50 times larger than that of CeYIG and YIG respectively. A theoretical model has been proposed for Faraday rotation based on density matrix method and an excellent agreement between experiment and theory is found. © 2012 Optical Society of America

Gritty Surface Sample Holder Invented To Obtain Correct X-ray Absorption Fine Structure Spectra for Concentrated Materials by Fluorescence Yield.

PubMed

Abe, Hitoshi; Niwa, Yasuhiro; Kimura, Masao; Murakami, Youichi; Yokoyama, Toshiharu; Hosono, Hideo

2016-04-05

A gritty surface sample holder has been invented to obtain correct XAFS spectra for concentrated samples by fluorescence yield (FY). Materials are usually mixed with boron nitride (BN) to prepare proper concentrations to measure XAFS spectra. Some materials, however, could not be mixed with BN and would be measured in too concentrated conditions to obtain correct XAFS spectra. Consequently, XAFS spectra will be incorrect typically with decreased intensities of the peaks. We have invented the gritty surface sample holders to obtain correct XAFS spectra even for concentrated materials for FY measurements. Pure Cu and CuO powders were measured mounted on the sample holders, and the same spectra were obtained as transmission spectra of properly prepared samples. This sample holder is useful to measure XAFS for any concentrated materials.

Real-time X-ray Diffraction: Applications to Materials Characterization

NASA Technical Reports Server (NTRS)

Rosemeier, R. G.

1984-01-01

With the high speed growth of materials it becomes necessary to develop measuring systems which also have the capabilities of characterizing these materials at high speeds. One of the conventional techniques of characterizing materials was X-ray diffraction. Film, which is the oldest method of recording the X-ray diffraction phenomenon, is not quite adequate in most circumstances to record fast changing events. Even though conventional proportional counters and scintillation counters can provide the speed necessary to record these changing events, they lack the ability to provide image information which may be important in some types of experiment or production arrangements. A selected number of novel applications of using X-ray diffraction to characterize materials in real-time are discussed. Also, device characteristics of some X-ray intensifiers useful in instantaneous X-ray diffraction applications briefly presented. Real-time X-ray diffraction experiments with the incorporation of image X-ray intensification add a new dimension in the characterization of materials. The uses of real-time image intensification in laboratory and production arrangements are quite unlimited and their application depends more upon the ingenuity of the scientist or engineer.

Archetypal structure of ultrathin alumina films: Grazing-incidence x-ray diffraction on Ni(111)

NASA Astrophysics Data System (ADS)

Prévot, G.; Le Moal, S.; Bernard, R.; Croset, B.; Lazzari, R.; Schmaus, D.

2012-05-01

We have studied by grazing-incidence x-ray diffraction the atomic structure of an ultrathin alumina film grown on Ni(111). We show that, since there is neither registry between the film and the substrate nor induced Ni relaxations, this system appears to be a prototypical freestanding oxide layer. We have been able to unambiguously determine the three-dimensional structure of the film, which consists of a substrate/Al16/O24/Al24/O28 stacking within a (18.23 × 10.53 Å) R0° unit cell. From the different Al coordinations (3/4/5) in the layer and from the precise determination of the Al-O interatomic distances, we conclude that the film structure presents some similarities with the η phase of bulk alumina, which also has a high surface/bulk ratio. The precise comparison between these two structures allows us to explain that the perfect 3 ratio between the two sides of the mesh of the film is governed by the stacking of the two central planes, combining oxygen close-packed atoms below Al atoms in tetrahedral or pyramidal positions. Moreover, Al atoms at the interface plane of the ultrathin film adopt a quasitrihedral configuration, which confirms that, in the alumina η phase, Al atoms with such a coordination are located near the surface of the nanocrystals. The atomic structure is also very close to the one first proposed by Kresse [G. Kresse, M. Schmid, E. Napetschnig, M. Shishkin, L. Köhler, and P. Varga, ScienceSCIEAS0036-807510.1126/science.1107783 308, 1440 (2005)] for alumina films on NiAl(110). This strongly suggests that this atomic model, within small variations, can be extended to ultrathin alumina film on numerous other metal substrates and may be quasi-intrinsic to a freestanding layer rather than governed by the interactions between the film and the substrate.

In-situ X-Ray Analysis of Rapid Thermal Processing for Thin-Film Solar Cells: Closing the Gap between Production and Laboratory Efficiency

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

Toney, Michael F.; van Hest, Maikel F. A. M.

empirically. Again, the proposed in situ monitoring will provide insight into the conversion process. We have developed a unique instrument for in situ monitoring of the reaction process during RTP. The most fundamental property to monitor is the atomic arrangement (for solids, crystalline structure) and thus we have focused on this property. The chamber was designed to collect X-ray diffraction (XRD) for crystal phase determination, although it has lent insight in the formation of liquids. We designed and constructed both inert (air) and reactive (S/Se) versions of this chamber. We have applied the RTP-XRD methodology to: silicon solar cell electrical contact formation; the reaction sequence for forming CIGS PV thin films from copper selenide and indium gallium selenide precursors; the phase sequence for forming HC(NH2)2PbI3 (FAPbI3) and CH3NH3PbI3 (MAPbI3) hybrid-perovskite PV thin films. The RTP instrument enables real-time collection of X-ray diffraction data with intervals as short as 100 ms, and while heating at ramp rates as high 100 ºCs-1 up to 1200 ºC. The system is portable and can be installed on a synchrotron beamline. The RTP reactor consists of a metallic body (front cap assembly, central block and end cap assembly) that houses a quartz reaction chamber. The sample is secured inside the reaction chamber on a sample holder connected to the front-cap assembly. Modifications of the chamber were made for safely handling sulfur and selenium vapor environments. A Se/S source holder was added to generate a Se/S over pressure in the chamber on heating and the entrance window is made wider in order to accommodate the detachable additional holder. Se/S are toxic in nature and therefore a proper Se/S trapping is used before releasing the gases to exhaust. Screen-printing provides an economically attractive means for making Ag electrical contacts to Si solar cells, but the use of Ag substantiates a significant manufacturing cost, and the glass frit used in the paste to

X-Ray Excited Luminescence Chemical Imaging of Bacterial Growth on Surfaces Implanted in Tissue.

PubMed

Wang, Fenglin; Raval, Yash; Tzeng, Tzuen-Rong J; Anker, Jeffrey N

2015-04-22

A pH sensor film is developed that can be coated on an implant surface and imaged using a combination of X-ray excitation and visible spectroscopy to monitor bacterial infection and treatment of implanted medical devices (IMDs) through tissue. X-ray scintillators in the pH sensor film generate light when an X-ray beam irradiates them. This light first passes through a layer containing pH indicator that alters the spectrum according to pH, then passes through and out of the tissue where it is detected by a spectrometer. A reference region on the film is used to account for spectral distortion from wavelength-dependent absorption and scattering in the tissue. pH images are acquired by moving the sample relative to the X-ray beam and collecting a spectrum at each location, with a spatial resolution limited by the X-ray beam width. Using this X-ray excited luminescence chemical imaging (XELCI) to map pH through ex vivo porcine tissue, a pH drop is detected during normal bacterial growth on the sensor surface, and a restoration of the pH to the bulk value during antibiotic treatment over the course of hours with milli-meter resolution. Overall, XELCI provides a novel approach to noninvasively image surface pH for studying implant infections and treatments. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reflective Coating for Lightweight X-Ray Optics

NASA Technical Reports Server (NTRS)

Chan, Kai-Wing; Zhang, William W.; Windt, David; Hong, Mao-Ling; Saha, Timo; McClelland, Ryan; Sharpe, Marton; Dwivedi, Vivek H.

2012-01-01

X-ray reflective coating for next generation's lightweight, high resolution, optics for astronomy requires thin-film deposition that is precisely fine-tuned so that it will not distort the thin sub-mm substrates. Film of very low stress is required. Alternatively, mirror distortion can be cancelled by precisely balancing the deformation from multiple films. We will present results on metallic film deposition for the lightweight optics under development. These efforts include: low-stress deposition by magnetron sputtering and atomic layer deposition of the metals, balancing of gross deformation with two-layer depositions of opposite stresses and with depositions on both sides of the thin mirrors.

Design and fabrication of adjustable x-ray optics using piezoelectric thin films

NASA Astrophysics Data System (ADS)

Walker, J.; Liu, T.; Tendulkar, M.; Burrows, D.; DeRoo, C. T.; Allured, R.; Hertz, E.; Cotroneo, V.; Reid, P.; Schwartz, E. D.; Jackson, T. N.; Trolier-McKinstry, S.

2017-08-01

Piezoelectric adjustable optics are being developed for high throughput, high resolution, low mass Xray mirror assemblies. These optics require robust piezoelectric thin films and reproducible lithographic patterning on curved glass substrates. This work details the cleaning of Corning Eagle XG glass substrates for thin shell X-ray mirrors by a three stage acid and solvent cleaning procedure before a 0.02 μm Ti adhesion layer and a 0.1 μm Pt bottom electrode layer was deposited using DC magnetron sputtering. Piezoelectric Pb(Zr0.52Ti0.48)0.99Nb0.01O3 thin films with a thickness of 1.5 μm were then deposited by radio frequency magnetron sputtering in three 0.5 µm layers with intermittent annealing steps in a rapid thermal annealing furnace at 650°C for 60 seconds. Defects observed in the piezoelectric thin films were linked to residue remaining on the glass after cleaning. 112 piezoelectric cells and 100 μm wide conductive Pt traces were patterned using bilayer photolithography. The photoresist layers were deposited using spin coating at 2000 and 4000 RPM to achieve uniform 1 μm thick layers, resulting in reproducibly resolved features with limiting resolutions of approximately >25 μm. The resulting mirror pieces achieved a 100% yield, with average relative permittivity of 1270, dielectric loss 0.047, coercive field 30 kV/cm and remanent polarization of 20 μC/cm2 . While the defects observed in the films appeared to have not influence on the electrical properties, additional cleaning steps using DI water were proposed to further reduce their presence.

Mechanical design of thin-film diamond crystal mounting apparatus with optimized thermal contact and crystal strain for coherence preservation x-ray optics

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

Shu, Deming; Shvydko, Yury; Stoupin, Stanislav

A method and mechanical design for a thin-film diamond crystal mounting apparatus for coherence preservation x-ray optics with optimized thermal contact and minimized crystal strain are provided. The novel thin-film diamond crystal mounting apparatus mounts a thin-film diamond crystal supported by a thick chemical vapor deposition (CVD) diamond film spacer with a thickness slightly thicker than the thin-film diamond crystal, and two groups of thin film thermal conductors, such as thin CVD diamond film thermal conductor groups separated by the thick CVD diamond spacer. The two groups of thin CVD film thermal conductors provide thermal conducting interface media with themore » thin-film diamond crystal. A piezoelectric actuator is integrated into a flexural clamping mechanism generating clamping force from zero to an optimal level.« less

Technology Requirements For a Square-Meter, Arcsecond-Resolution Telescope for X-Rays: The SMART-X Mission

NASA Technical Reports Server (NTRS)

Schwartz, Daniel A.; Allured, Ryan; Bookbinder, Jay; Cotroneo, Vincenzo; Forman, William; Freeman, Mark; McMuldroch, Stuart; Reid, Paul; Tananbaum, Harvey; Vikhlinin, Alexey;

Parametric studies and characterization measurements of x-ray lithography mask membranes

NASA Astrophysics Data System (ADS)

Wells, Gregory M.; Chen, Hector T. H.; Engelstad, Roxann L.; Palmer, Shane R.

1991-08-01

The techniques used in the experimental characterization of thin membranes are considered for their potential use as mask blanks for x-ray lithography. Among the parameters of interest for this evaluation are the film's stress, fracture strength, uniformity of thickness, absorption in the x-ray and visible spectral regions and the modulus and grain structure of the material. The experimental techniques used for measuring these properties are described. The accuracy and applicability of the assumptions used to derive the formulas that relate the experimental measurements to the parameters of interest are considered. Experimental results for silicon carbide and diamond films are provided. Another characteristic needed for an x-ray mask carrier is radiation stability. The number of x-ray exposures expected to be performed in the lifetime of an x-ray mask on a production line is on the order of 107. The dimensional stability requirements placed on the membranes during this period are discussed. Interferometric techniques that provide sufficient sensitivity for these stability measurements are described. A comparison is made between the different techniques that have been developed in term of the information that each technique provides, the accuracy of the various techniques, and the implementation issues that are involved with each technique.

Microwave Kinetic Inductance Detectors: Large Format X-ray Spectral Imagers for the Next Generation of X-ray Telescopes

NASA Astrophysics Data System (ADS)

Eckart, Megan E.; Mazin, B. A.; Bumble, B.; Golwala, S. R.; Zmuidzinas, J.; Day, P. K.; Harrison, F. A.

2006-09-01

Microwave Kinetic Inductance Detectors (MKIDs) have the potential to provide megapixel imagers with few eV spectral resolution for future X-ray missions such as Gen-X. MKIDs offer the advantage over many other cryogenic detector technologies that they can be easily multiplexed, so that arrays with many thousand pixels are readily achievable. In addition, the readout electronics can be operated at room temperature, a significant advantage for space applications. MKIDs exploit the dependence of surface impedance of a superconductorwith the quasiparticle density. Quasiparticles are created by absorption of X-rays, with number proportional to the X-ray energy. The impedance change may be sensitively measured using a thin-film resonant circuit. The practical application of MKIDs for photon detection requires a method of efficiently coupling the photon energy to the MKID. To apply the MKID scheme to X-ray detection we pattern tantalum strips with aluminum MKIDs attached at each end. An incident X-ray is absorbed in the Ta and creates millions of quasiparticle excitations, which diffuse to each end of the strip, finally entering the Al resonators where they are trapped and sensed. Simultaneous monitoring of the signal at both ends of the strip allow position and energy determination for each photon. We have demonstrated working strip detectors in the laboratory, and will present our measurements of the quasiparticle diffusion constant and the quasiparticle lifetime in tantalum, the aluminum quasiparticle lifetime, and the energy resolution of the detector. We will also discuss ideas for future detector designs and suggest ultimate performance goals for X-ray astronomy applications.

Hard X-ray photoelectron spectroscopy of Li{sub x}Ni{sub 1−x}O epitaxial thin films with a high lithium content

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

Kumara, L. S. R., E-mail: KUMARA.Rosantha@nims.go.jp; Yang, Anli; Sakata, Osami, E-mail: SAKATA.Osami@nims.go.jp

2014-07-28

The core-level and valence-band electronic structures of Li{sub x}Ni{sub 1−x}O epitaxial thin films with x = 0, 0.27, and 0.48 were studied by hard X-ray photoelectron spectroscopy. A double peak structure, consisting of a main peak and a shoulder peak, and a satellite structure were observed in the Ni 2p{sub 3/2} core-level spectra. The intensity ratio of the shoulder to main peak in this double peak structure increased with increasing lithium content in Li{sub x}Ni{sub 1−x}O. This lithium doping dependence of the Ni 2p{sub 3/2} core-level spectra was investigated using an extended cluster model, which included the Zhang–Rice (ZR) doubletmore » bound states arising from a competition between O 2p – Ni 3d hybridization and the Ni on-site Coulomb interaction. The results indicated that the change in the intensity ratio in the main peak is because of a reduction in the ZR doublet bound states from lithium substitutions. This strongly suggests that holes compensating Li doping in Li{sub x}Ni{sub 1−x}O are of primarily ZR character.« less

Determination of the Mass Absorption Coefficient in Two-Layer Ti/V and V/Ti Thin Film Systems by the X-Ray Fluorescence Method

NASA Astrophysics Data System (ADS)

Mashin, N. I.; Chernyaeva, E. A.; Tumanova, A. N.; Gafarova, L. M.

2016-03-01

A new XRF procedure for the determination of the mass absorption coefficient in thin film Ti/V and V/Ti two-layer systems has been proposed. The procedure uses easy-to-make thin-film layers of sputtered titanium and vanadium on a polymer film substrate. Correction coefficients have been calculated that take into account attenuation of primary radiation of the X-ray tube, as well as attenuation of the spectral line of the bottom layer element in the top layer.

Finite element analyses of thin film active grazing incidence x-ray optics

NASA Astrophysics Data System (ADS)

Davis, William N.; Reid, Paul B.; Schwartz, Daniel A.

2010-09-01

The Chandra X-ray Observatory, with its sub-arc second resolution, has revolutionized X-ray astronomy by revealing an extremely complex X-ray sky and demonstrating the power of the X-ray window in exploring fundamental astrophysical problems. Larger area telescopes of still higher angular resolution promise further advances. We are engaged in the development of a mission concept, Generation-X, a 0.1 arc second resolution x-ray telescope with tens of square meters of collecting area, 500 times that of Chandra. To achieve these two requirements of imaging and area, we are developing a grazing incidence telescope comprised of many mirror segments. Each segment is an adjustable mirror that is a section of a paraboloid or hyperboloid, aligned and figure corrected in situ on-orbit. To that end, finite element analyses of thin glass mirrors are performed to determine influence functions for each actuator on the mirrors, in order to develop algorithms for correction of mirror deformations. The effects of several mirror mounting schemes are also studied. The finite element analysis results, combined with measurements made on prototype mirrors, will be used to further refine the correction algorithms.

Water window imaging x ray microscope

NASA Technical Reports Server (NTRS)

Hoover, Richard B. (Inventor)

1992-01-01

A high resolution x ray microscope for imaging microscopic structures within biological specimens has an optical system including a highly polished primary and secondary mirror coated with identical multilayer coatings, the mirrors acting at normal incidence. The coatings have a high reflectivity in the narrow wave bandpass between 23.3 and 43.7 angstroms and have low reflectivity outside of this range. The primary mirror has a spherical concave surface and the secondary mirror has a spherical convex surface. The radii of the mirrors are concentric about a common center of curvature on the optical axis of the microscope extending from the object focal plane to the image focal plane. The primary mirror has an annular configuration with a central aperture and the secondary mirror is positioned between the primary mirror and the center of curvature for reflecting radiation through the aperture to a detector. An x ray filter is mounted at the stage end of the microscope, and film sensitive to x rays in the desired band width is mounted in a camera at the image plane of the optical system. The microscope is mounted within a vacuum chamber for minimizing the absorption of x rays in air from a source through the microscope.

Phase degradation in B xGa 1–xN films grown at low temperature by metalorganic vapor phase epitaxy

DOE PAGES

Gunning, Brendan P.; Moseley, Michael W.; Koleske, Daniel D.; ...

2016-11-01

Using metalorganic vapor phase epitaxy, a comprehensive study of B xGa 1-xN growth on GaN and AlN templates is described. BGaN growth at high-temperature and high-pressure results in rough surfaces and poor boron incorporation efficiency, while growth at low-temperature and low-pressure (750–900 °C and 20 Torr) using nitrogen carrier gas results in improved surface morphology and boron incorporation up to ~7.4% as determined by nuclear reaction analysis. However, further structural analysis by transmission electron microscopy and x-ray pole figures points to severe degradation of the high boron composition films, into a twinned cubic structure with a high density of stackingmore » faults and little or no room temperature photoluminescence emission. Films with <1% triethylboron (TEB) flow show more intense, narrower x-ray diffraction peaks, near-band-edge photoluminescence emission at ~362 nm, and primarily wurtzite-phase structure in the x-ray pole figures. For films with >1% TEB flow, the crystal structure becomes dominated by the cubic phase. As a result, only when the TEB flow is zero (pure GaN), does the cubic phase entirely disappear from the x-ray pole figure, suggesting that under these growth conditions even very low boron compositions lead to mixed crystalline phases.« less

Phase degradation in B xGa 1–xN films grown at low temperature by metalorganic vapor phase epitaxy

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

Gunning, Brendan P.; Moseley, Michael W.; Koleske, Daniel D.

Using metalorganic vapor phase epitaxy, a comprehensive study of B xGa 1-xN growth on GaN and AlN templates is described. BGaN growth at high-temperature and high-pressure results in rough surfaces and poor boron incorporation efficiency, while growth at low-temperature and low-pressure (750–900 °C and 20 Torr) using nitrogen carrier gas results in improved surface morphology and boron incorporation up to ~7.4% as determined by nuclear reaction analysis. However, further structural analysis by transmission electron microscopy and x-ray pole figures points to severe degradation of the high boron composition films, into a twinned cubic structure with a high density of stackingmore » faults and little or no room temperature photoluminescence emission. Films with <1% triethylboron (TEB) flow show more intense, narrower x-ray diffraction peaks, near-band-edge photoluminescence emission at ~362 nm, and primarily wurtzite-phase structure in the x-ray pole figures. For films with >1% TEB flow, the crystal structure becomes dominated by the cubic phase. As a result, only when the TEB flow is zero (pure GaN), does the cubic phase entirely disappear from the x-ray pole figure, suggesting that under these growth conditions even very low boron compositions lead to mixed crystalline phases.« less

Effects of strain relaxation in Pr 0.67Sr 0.33MnO 3 films probed by polarization dependent X-ray absorption near edge structure

DOE PAGES

zhang, Bangmin; Chen, Jingsheng; Venkatesan, T.; ...

2016-01-28

In this study, the Mn K edge X-ray absorption near edge structure (XANES) of Pr 0.67Sr 0.33MnO 3 films with different thicknesses on (001) LaAlO 3 substrate were measured, and the effects of strain relaxation on film properties were investigated. The films experienced in-plane compressive strain and out-of-plane tensile strain. Strain relaxation evolved with the film thickness. In the polarization dependent XANES measurements, the in-plane (parallel) and out-of-plane (perpendicular) XANES spectrocopies were anisotropic with different absorption energy E r. The resonance energy Er along two directions shifted towards each other with increasing film thickness. Based on the X-ray diffraction results,more » it was suggested that the strain relaxation weakened the difference of the local environment and probability of electronic charge transfer (between Mn 3d and O 2p orbitals) along the in-plane and out-of-plane directions, which was responsible for the change of E r. XANES is a useful tool to probe the electronic structures, of which the effects on magnetic properties with the strain relaxation was also been studied.« less

Fabrication of a Polymer Micro Needle Array by Mask-Dragging X-Ray Lithography and Alignment X-Ray Lithography

NASA Astrophysics Data System (ADS)

Li, Yi-Gui; Yang, Chun-Sheng; Liu, Jing-Quan; Sugiyama, Susumu

2011-03-01

Polymer materials such as transparent thermoplastic poly(methyl methacrylate) (PMMA) have been of great interest in the research and development of integrated circuits and micro-electromechanical systems due to their relatively low cost and easy process. We fabricated PMMA-based polymer hollow microneedle arrays by mask-dragging and aligning x-ray lithography. Techniques for 3D micromachining by direct lithography using x-rays are developed. These techniques are based on using image projection in which the x-ray is used to illuminate an appropriate gold pattern on a polyimide film mask. The mask is imaged onto the PMMA sample. A pattern with an area of up to 100 × 100mm2 can be fabricated with sub-micron resolution and a highly accurate order of a few microns by using a dragging mask. The fabrication technology has several advantages, such as forming complex 3D micro structures, high throughput and low cost.

Structural and Optical Properties of Cd 1- x Se x Thin Films Deposited by Electron Beam Evaporation Technique

NASA Astrophysics Data System (ADS)

Tripathi, Ravishankar Nath; Verma, Aneet Kumar; Rahul, Vishwakarma, S. R.

2011-10-01

Cadmium selenide (CdSe) thin films deposited by means of electron beam evaporation technique under high vacuum ˜10 -5 torr on ultrasonically cleaned glass substrate. Using stating materials of various compositions of cadmium and selenium using formula Cd 1- x Se x where x is orbitory constant having value 0.20≤ x ≤0.40 here we take less value of x for the creation of anion vacancy in thin films. In present work the structural properties have been studies using XRD technique and found that starting materials and thin films both are polycrystalline in nature having hexagonal structure. Here we study the effect of composition ratio Cd/Se in starting material and its prepared thin films on its grain size and lattice parameter. From the analysis of X-Ray diffractogram found that lattice parameter and grain size both are decreases with increasing Cd/Se ratio in thin films as well as in starting material the preferred orientation in thin films along (100) plane. The surface morphology was studied using SEM characterization and found that films are smooth and homogeneous. The films have been analysed for optical band gap and absorbed a direct band gap.

In situ micro-Raman analysis and X-ray diffraction of nickel silicide thin films on silicon.

PubMed

Bhaskaran, M; Sriram, S; Perova, T S; Ermakov, V; Thorogood, G J; Short, K T; Holland, A S

2009-01-01

This article reports on the in situ analysis of nickel silicide (NiSi) thin films formed by thermal processing of nickel thin films deposited on silicon substrates. The in situ techniques employed for this study include micro-Raman spectroscopy (microRS) and X-ray diffraction (XRD); in both cases the variations for temperatures up to 350 degrees C has been studied. Nickel silicide thin films formed by vacuum annealing of nickel on silicon were used as a reference for these measurements. In situ analysis was carried out on nickel thin films on silicon, while the samples were heated from room temperature to 350 degrees C. Data was gathered at regular temperature intervals and other specific points of interest (such as 250 degrees C, where the reaction between nickel and silicon to form Ni(2)Si is expected). The transformations from the metallic state, through the intermediate reaction states, until the desired metal-silicon reaction product is attained, are discussed. The evolution of nickel silicide from the nickel film can be observed from both the microRS and XRD in situ studies. Variations in the evolution of silicide from metal for different silicon substrates are discussed, and these include (100) n-type, (100) p-type, and (110) p-type silicon substrates.

Soft X-ray imaging of thick carbon-based materials using the normal incidence multilayer optics.

PubMed

Artyukov, I A; Feschenko, R M; Vinogradov, A V; Bugayev, Ye A; Devizenko, O Y; Kondratenko, V V; Kasyanov, Yu S; Hatano, T; Yamamoto, M; Saveliev, S V

2010-10-01

The high transparency of carbon-containing materials in the spectral region of "carbon window" (lambda approximately 4.5-5nm) introduces new opportunities for various soft X-ray microscopy applications. The development of efficient multilayer coated X-ray optics operating at the wavelengths of about 4.5nm has stimulated a series of our imaging experiments to study thick biological and synthetic objects. Our experimental set-up consisted of a laser plasma X-ray source generated with the 2nd harmonics of Nd-glass laser, scandium-based thin-film filters, Co/C multilayer mirror and X-ray film UF-4. All soft X-ray images were produced with a single nanosecond exposure and demonstrated appropriate absorption contrast and detector-limited spatial resolution. A special attention was paid to the 3D imaging of thick low-density foam materials to be used in design of laser fusion targets.

X-Rays

MedlinePlus

X-rays are a type of radiation called electromagnetic waves. X-ray imaging creates pictures of the inside of ... different amounts of radiation. Calcium in bones absorbs x-rays the most, so bones look white. Fat ...

Observation of electric potential in organic thin-film transistor by bias-applied hard X-ray photoemission spectroscopy

NASA Astrophysics Data System (ADS)

Watanabe, Takeshi; Tada, Keisuke; Yasuno, Satoshi; Oji, Hiroshi; Yoshimoto, Noriyuki; Hirosawa, Ichiro

2016-03-01

The effect of gate voltage on electric potential in a pentacene (PEN) layer was studied by hard X-ray photoelectron spectroscopy under a bias voltage. It was observed that applying a negative gate voltage substantially increases the width of a C 1s peak. This suggested that injected and accumulated carriers in an organic thin film transistor channel modified the potential depth profile in PEN. It was also observed that the C 1s kinetic energy tends to increase monotonically with threshold voltage.

LPE growth and characterization of InAs1-xNx films

NASA Astrophysics Data System (ADS)

Lv, Y. F.; Hu, S. H.; Yang, X. Y.; Wang, Y.; Sun, C. H.; Qiu, F.; Cong, R.; Dong, W. J.; Zhang, Y.; Yu, G. L.; Dai, N.

2014-07-01

A series of InAs1-xNx films have been successfully grown on (100) oriented InAs substrates by liquid phase epitaxy technique. Samples with different nitrogen contents have been analyzed by high-resolution x-ray diffraction measurement, which confirms the incorporation of N in the epilayers. N-related modes are detected in the Raman spectra of InAs1-xNx epilayers. The fundamental absorption edges of InAs1-xNx films obtained by Fourier transform infrared transmission spectroscopy exhibit a red-shift compared with that of InAs homoepilayer.

Assessment study of ion-exchange chromatography combined with solution X-ray scattering measurement for protein characterization.

PubMed

Watanabe, Yasushi

2018-03-02

The performance of ion-exchange chromatography combined with small-angle X-ray scattering measurement was evaluated by characterization of the hen egg white lysozyme as a model protein. The X-ray transmittance was estimated using a micro-ionization chamber equipped with a sample cell holder for the real-time monitoring of the X-ray beam strength through the salt gradient elution. The radius of gyration of the eluted protein was estimated to be 1.50 ± 0.06 (n = 3) nm and 1.4 ± 0.1 nm as the value at the zero protein concentration. By using the X-ray transmittance values for the scattering intensity correction, the molecular weight of the eluted protein was estimated to be 15,200 ± 500 (n = 3) and 14,400 ± 200 as the value at the zero protein concentration. These values are close to those of the monomer of this protein. The ion-exchange chromatography combined with the small-angle X-ray scattering measurement system equipped with the X-ray transmittance monitor is a reliable method for protein characterization in solution. Copyright © 2018 Elsevier B.V. All rights reserved.

Spatially resolved high-resolution x-ray spectroscopy of high-current plasma-focus discharges.

PubMed

Zając, S; Rzadkiewicz, J; Rosmej, O; Scholz, M; Yongtao, Zhao; Gójska, A; Paduch, M; Zielińska, E

2010-10-01

Soft x-ray emission from a Mather-type plasma-focus device (PF-1000) operated at ∼400 kJ was measured. The high density and temperature plasma were generated by the discharge in the deuterium-argon gas mixture in the modified (high-current) plasma-focus configuration. A spherically bent mica crystal spectrograph viewing the axial output of the pinch region was used to measure the x-ray spectra. Spatially resolved spectra including the characteristic x-ray lines of highly ionized Ar and continua were recorded by means of an x-ray film. The x-ray emission of PF-1000 device was studied at different areas of the pinch.

Spatially resolved high-resolution x-ray spectroscopy of high-current plasma-focus discharges

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

ZajaPc, S.; Rzadkiewicz, J.; Scholz, M.

Soft x-ray emission from a Mather-type plasma-focus device (PF-1000) operated at {approx}400 kJ was measured. The high density and temperature plasma were generated by the discharge in the deuterium-argon gas mixture in the modified (high-current) plasma-focus configuration. A spherically bent mica crystal spectrograph viewing the axial output of the pinch region was used to measure the x-ray spectra. Spatially resolved spectra including the characteristic x-ray lines of highly ionized Ar and continua were recorded by means of an x-ray film. The x-ray emission of PF-1000 device was studied at different areas of the pinch.

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

DOE PAGES

Lee, J. H.; Tung, I. C.; Chang, S. -H.; ...

2016-01-05

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-raymore » 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. Finally, 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.« less

X-ray diffraction on radioactive materials

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

Schiferl, D.; Roof, R.B.

1978-01-01

X-ray diffraction studies on radioactive materials are discussed with the aim of providing a guide to new researchers in the field. Considerable emphasis is placed on the safe handling and loading of not-too-exotic samples. Special considerations such as the problems of film blackening by the gamma rays and changes induced by the self-irradiation of the sample are covered. Some modifications of common diffraction techniques are presented. Finally, diffraction studies on radioactive samples under extreme conditions are discussed, with primary emphasis on high-pressure studies involving diamond-anvil cells.

Synthesis and characteristics of PbTe1-xSex thin films formed via electrodeposition

NASA Astrophysics Data System (ADS)

Bae, Sangwoo; Lee, Sangwon; Sohn, Ho-Sang; Lee, Ho Seong

2017-09-01

PbTe1-xSex films were grown using electrodeposition and their microstructural and electrical properties were investigated. The Se content incorporated in the PbTe1-xSex films increased with the Se content in the electrolyte. X-ray diffraction peaks of the PbTe1-xSex films shifted to higher angles according to Vegard's law. For the sample with a small Se content, the PbTe1-xSex films showed a characteristic feather-like dendrite, while PbTe1-xSex films with a higher Se content showed faceted particles. Transmission electron microscopy results showed that the feather-like dendritic PbTe1-xSex grew like a single crystal and a growing twinning was formed in some dendrites. With an increase in the Se content in the PbTe1-xSex thin films, the carrier concentrations increased but the mobility reduced. Electrical conductivity of the PbTe1-xSex thin films increased and then slightly decreased with increasing Se content.

X-Ray Spectroscopy of Ultra-Thin Oxide/Oxide Heteroepitaxial Films: A Case Study of Single-Nanometer VO2/TiO2

PubMed Central

Quackenbush, Nicholas F.; Paik, Hanjong; Woicik, Joseph C.; Arena, Dario A.; Schlom, Darrell G.; Piper, Louis F. J.

2015-01-01

Epitaxial ultra-thin oxide films can support large percent level strains well beyond their bulk counterparts, thereby enabling strain-engineering in oxides that can tailor various phenomena. At these reduced dimensions (typically < 10 nm), contributions from the substrate can dwarf the signal from the epilayer, making it difficult to distinguish the properties of the epilayer from the bulk. This is especially true for oxide on oxide systems. Here, we have employed a combination of hard X-ray photoelectron spectroscopy (HAXPES) and angular soft X-ray absorption spectroscopy (XAS) to study epitaxial VO2/TiO2 (100) films ranging from 7.5 to 1 nm. We observe a low-temperature (300 K) insulating phase with evidence of vanadium-vanadium (V-V) dimers and a high-temperature (400 K) metallic phase absent of V-V dimers irrespective of film thickness. Our results confirm that the metal insulator transition can exist at atomic dimensions and that biaxial strain can still be used to control the temperature of its transition when the interfaces are atomically sharp. More generally, our case study highlights the benefits of using non-destructive XAS and HAXPES to extract out information regarding the interfacial quality of the epilayers and spectroscopic signatures associated with exotic phenomena at these dimensions. PMID:28793516

X-Ray Spectroscopy of Ultra-Thin Oxide/Oxide Heteroepitaxial Films: A Case Study of Single-Nanometer VO2/TiO2.

PubMed

Quackenbush, Nicholas F; Paik, Hanjong; Woicik, Joseph C; Arena, Dario A; Schlom, Darrell G; Piper, Louis F J

2015-08-21

Epitaxial ultra-thin oxide films can support large percent level strains well beyond their bulk counterparts, thereby enabling strain-engineering in oxides that can tailor various phenomena. At these reduced dimensions (typically < 10 nm), contributions from the substrate can dwarf the signal from the epilayer, making it difficult to distinguish the properties of the epilayer from the bulk. This is especially true for oxide on oxide systems. Here, we have employed a combination of hard X-ray photoelectron spectroscopy (HAXPES) and angular soft X-ray absorption spectroscopy (XAS) to study epitaxial VO2/TiO2 (100) films ranging from 7.5 to 1 nm. We observe a low-temperature (300 K) insulating phase with evidence of vanadium-vanadium (V-V) dimers and a high-temperature (400 K) metallic phase absent of V-V dimers irrespective of film thickness. Our results confirm that the metal insulator transition can exist at atomic dimensions and that biaxial strain can still be used to control the temperature of its transition when the interfaces are atomically sharp. More generally, our case study highlights the benefits of using non-destructive XAS and HAXPES to extract out information regarding the interfacial quality of the epilayers and spectroscopic signatures associated with exotic phenomena at these dimensions.

X-ray Spectroscopy of Ultra-thin Oxide/oxide Heteroepitaxial Films: A Case Study of Single-nanometer VO2/TiO2

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

Quackenbush, Nicholas F.; Paik, Hanjong; Woicik, Joseph C.

2015-08-21

Epitaxial ultra-thin oxide films can support large percent level strains well beyond their bulk counterparts, thereby enabling strain-engineering in oxides that can tailor various phenomena. At these reduced dimensions (typically < 10 nm), contributions from the substrate can dwarf the signal from the epilayer, making it difficult to distinguish the properties of the epilayer from the bulk. This is especially true for oxide on oxide systems. Here, we have employed a combination of hard X-ray photoelectron spectroscopy (HAXPES) and angular soft X-ray absorption spectroscopy (XAS) to study epitaxial VO2/TiO2 (100) films ranging from 7.5 to 1 nm. We observe amore » low-temperature (300 K) insulating phase with evidence of vanadium-vanadium (V-V) dimers and a high-temperature (400 K) metallic phase absent of V-V dimers irrespective of film thickness. Results confirm that the metal insulator transition can exist at atomic dimensions and that biaxial strain can still be used to control the temperature of its transition when the interfaces are atomically sharp. Generally, our case study highlights the benefits of using non-destructive XAS and HAXPES to extract out information regarding the interfacial quality of the epilayers and spectroscopic signatures associated with exotic phenomena at these dimensions.« less

A novel x-ray imaging system and its imaging performance

NASA Astrophysics Data System (ADS)

Yu, Chunyu; Chang, Benkang; Wang, Shiyun; Zhang, Junju; Yao, Xiao

2006-09-01

Since x-ray was discovered and applied to the imaging technology, the x-ray imaging techniques have experienced several improvements, from film-screen, x-ray image intensifier, CR to DR. To store and transmit the image information conveniently, the digital imaging is necessary for the imaging techniques in medicine and biology. Usually as the intensifying screen technique as for concerned, to get the digital image signals, the CCD was lens coupled directly to the screen, but which suffers from a loss of x-ray signal and resulted in the poor x-ray image perfonnance. Therefore, to improve the image performance, we joined the brightness intensifier, which, was named the Low Light Level (LLL) image intensifier in military affairs, between the intensifying screen and the CCD and designed the novel x-ray imaging system. This design method improved the image performance of the whole system thus decreased the x-ray dose. Comparison between two systems with and without the brightness intensifier was given in detail in this paper. Moreover, the main noise source of the image produced by the novel system was analyzed, and in this paper, the original images produced by the novel x-ray imaging system and the processed images were given respectively. It was clear that the image performance was satisfied and the x-ray imaging system can be used in security checking and many other nondestructive checking fields.

[The clinical and X-ray classification of osteonecrosis of the low jaw].

PubMed

Medvedev, Iu A; Basin, E M; Sokolina, I A

2013-01-01

To elaborate a clinical and X-ray classification of osteonecrosis of the low jaw in people with desomorphine or pervitin addiction. Ninety-two patients with drug addiction who had undergone orthopantomography, direct frontal X-ray of the skull, and multislice computed tomography, followed by multiplanar and three-dimensional imaging reconstruction were examined. One hundred thirty four X-ray films and 74 computed tomographic images were analyzed. The authors proposed a clinical and X-ray classification of osteonecrosis of the low jaw in people with desomorphine or pervitin addiction and elaborated recommendations for surgical interventions on the basis of the developed classification. The developed clinical and X-ray classification and recommendations for surgical interventions may be used to treat osteonecroses of various etiology.

The Extended Range X-Ray Telescope center director's discretionary fund report

NASA Technical Reports Server (NTRS)

Hoover, R. B.; Cumings, N. P.; Hildner, E.; Moore, R. L.; Tandberg-Hanssen, E. A.

1985-01-01

An Extended Range X-Ray Telescope (ERXRT) of high sensitivity and spatial resolution capable of functioning over a broad region of the X-ray/XUV portion of the spectrum has been designed and analyzed. This system has been configured around the glancing-incidence Wolter Type I X-ray mirror system which was flown on the Skylab Apollo Telescope Mount as ATM Experiment S-056. Enhanced sensitivity over a vastly broader spectral range can be realized by the utilization of a thinned, back-illuminated, buried-channel Charge Coupled Device (CCD) as the X-ray/XUV detector rather than photographic film. However, to maintain the high spatial resolution inherent in the X-ray optics when a CCD of 30 micron pixel size is used, it is necessary to increase the telescope plate scale. This can be accomplished by use of a glancing-incidence X-ray microscope to enlarge and re-focus the primary image onto the focal surface of the CCD.

Soft x-ray spectroscopy studies of novel electronic materials using synchrotron radiation

NASA Astrophysics Data System (ADS)

Newby, David, Jr.

Soft x-ray spectroscopy can provide a wealth of information on the electronic structure of solids. In this work, a suite of soft x-ray spectroscopies is applied to organic and inorganic materials with potential applications in electronic and energy generation devices. Using the techniques of x-ray absorption (XAS), x-ray emission spectroscopy (XES), and x-ray photoemission spectroscopy (XPS), the fundamental properties of these different materials are explored. Cycloparaphenylenes (CPPs) are a recently synthesized family of cyclic hydrocarbons with very interesting properties and many potential applications. Unusual UV/Visible fluorescence trends have spurred a number of theoretical investigations into the electronic properties of the CPP family, but thus far no comprehensive electronic structure measurements have been conducted. XPS, XAS, and XES data for two varieties, [8]- and [10]-CPP, are presented here, and compared with the results of relevant DFT calculations. Turning towards more application-centered investigations, similar measurements are applied to two materials commonly used in solid oxide fuel cell (SOFC) cathodes: La1-xSrxMnO 3 (LSMO) and La1-xSr1- xCo1-yFe yO3 (LSCF). Both materials are structurally perovskites, but they exhibit strikingly different electronic properties. SOFC systems very efficiently produce electricity by catalyzing reactions between oxygen and petroleum-based hydrocarbons at high temperatures (> 800 C). Such systems are already utilized to great effect in many industries, but more widespread adoption could be had if the cells could operate at lower temperatures. Understanding the electronic structure and operational evolution of the cathode materials is essential for the development of better low-temperature fuel cells. LSCF is a mixed ion-electron conductor which holds promise for low-temperature SOFC applications. XPS spectra of LSCF thin films are collected as the films are heated and gas-dosed in a controlled environment. The

Magnetic and chemical nonuniformity in Ga{sub 1-x}Mn{sub x}As as probed with neutron & x-ray reflectivfity.

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

Kirby, B. J.; Borchers, J. A.; Rhyne, J. J.

We have used complementary neutron and x-ray reflectivity techniques to examine the depth profiles of a series of as-grown and annealed Ga{sub 1-x}Mn{sub x}As thin films. A magnetization gradient is observed for two as-grown films and originates from a nonuniformity of Mn at interstitial sites, and not from local variations in Mn at Ga sites. Furthermore, we see that the depth-dependent magnetization can vary drastically among as-grown Ga{sub 1-x}Mn{sub x}As films despite being deposited under seemingly similar conditions. These results imply that the depth profile of interstitial Mn is dependent not only on annealing, but is also extremely sensitive tomore » initial growth conditions. We observe that annealing improves the magnetization by producing a surface layer that is rich in Mn and O, indicating that the interstitial Mn migrates to the surface. Finally, we expand upon our previous neutron reflectivity study of Ga{sub 1-x}Mn{sub x}As, by showing how the depth profile of the chemical composition at the surface and through the film thickness is directly responsible for the complex magnetization profiles observed in both as-grown and annealed films.« less

Mammographic x-ray unit kilovoltage test tool based on k-edge absorption effect.

PubMed

Napolitano, Mary E; Trueblood, Jon H; Hertel, Nolan E; David, George

2002-09-01

A simple tool to determine the peak kilovoltage (kVp) of a mammographic x-ray unit has been designed. Tool design is based on comparing the effect of k-edge discontinuity of the attenuation coefficient for a series of element filters. Compatibility with the mammography accreditation phantom (MAP) to obtain a single quality control film is a second design objective. When the attenuation of a series of sequential elements is studied simultaneously, differences in the absorption characteristics due to the k-edge discontinuities are more evident. Specifically, when the incident photon energy is higher than the k-edge energy of a number of the elements and lower than the remainder, an inflection may be seen in the resulting attenuation data. The maximum energy of the incident photon spectra may be determined based on this inflection point for a series of element filters. Monte Carlo photon transport analysis was used to estimate the photon transmission probabilities for each of the sequential k-edge filter elements. The photon transmission corresponds directly to optical density recorded on mammographic x-ray film. To observe the inflection, the element filters chosen must have k-edge energies that span a range greater than the expected range of the end point energies to be determined. For the design, incident x-ray spectra ranging from 25 to 40 kVp were assumed to be from a molybdenum target. Over this range, the k-edge energy changes by approximately 1.5 keV between sequential elements. For this design 21 elements spanning an energy range from 20 to 50 keV were chosen. Optimum filter element thicknesses were calculated to maximize attenuation differences at the k-edge while maintaining optical densities between 0.10 and 3.00. Calculated relative transmission data show that the kVp could be determined to within +/-1 kV. To obtain experimental data, a phantom was constructed containing 21 different elements placed in an acrylic holder. MAP images were used to determine

Preparation of CuIn{sub x}Ga{sub 1{minus}x}Se{sub 2} thin films on Si substrates

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

Yamamoto, Yukio; Yamaguchi, Toshiyuki; Suzuki, Masayoshi

For fabricating efficient tandem solar cells, CuIn{sub x}Ga{sub 1{minus}x}Se{sub 2} thin films have been prepared on Si(100), Si(110) and Si(111) substrates in the temperature range (R.T.{approximately}400 C) by rf sputtering. From EPMA analysis, these sputtered thin films are found to be nearly stoichiometric over the whole substrate temperature range, irrespective of the azimuth plane of the Si substrate. XPS studies showed that the compositional depth profile in these thin films is uniform. X-ray diffraction analysis indicated that all the thin films had a chalcopyrite structure. CuIn{sub x}Ga{sub 1{minus}x}Se{sub 2} thin films were strongly oriented along the (112) plane with increasingmore » the substrate temperature, independent of the azimuth plane of the Si substrate, suggesting the larger grain growth.« less

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

DOE PAGES

Shin, Kyung -Wook; Karim, Karim S.

2017-03-15

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

Dedicated Stereophotogrammetric X-Ray System For Craniofacial Research And Treatment Planning

NASA Astrophysics Data System (ADS)

Baumrind, Sheldon; Moffitt, Francis; Curry, Sean; Isaacson, Robert J.

1983-07-01

We have constructed and brought into use what we believe to be the first dedicated coplanar craniofacial stereometric x-ray system for clinical use. Paired Machlett Dynamax 50/58 x-ray tubes with 0.3 mm focal spots are employed. Displacement between emitters is 16 inches. The focus film distance for both emitters is 66.5 inches. The mid-sagittal plane to focus distance is 60 inches. One film of each stereo pair conforms with the standards of the Second Roentgenocephalometric Workshop and can be used to make all standard two-dimensional orthodontic and cephalometric measurements. When supplemented by data from the conjugate film, a three-dimensional coordinate map can be generated as a machine operation. Specialized complementary software has been developed to increase the reliability of landmark location both in two and in three dimensions.

Phonon Lifetime Observation in Epitaxial ScN Film with Inelastic X-Ray Scattering Spectroscopy.

PubMed

Uchiyama, H; Oshima, Y; Patterson, R; Iwamoto, S; Shiomi, J; Shimamura, K

2018-06-08

Phonon-phonon scattering dominates the thermal properties in nonmetallic materials, and it directly influences device performance in applications. The understanding of the scattering has been progressing using computational approaches, and the direct and systematic observation of phonon modes that include momentum dependences is desirable. We report experimental data on the phonon dispersion curves and lifetimes in an epitaxially grown ScN film using inelastic x-ray scattering measurements. The momentum dependence of the optical phonon lifetimes is estimated from the spectral width, and the highest-energy phonon mode around the zone center is found to possess a short lifetime of 0.21 ps. A comparison with first-principles calculations shows that our observed phonon lifetimes are quantitatively explained by three-body phonon-phonon interactions.

Phonon Lifetime Observation in Epitaxial ScN Film with Inelastic X-Ray Scattering Spectroscopy

NASA Astrophysics Data System (ADS)

Uchiyama, H.; Oshima, Y.; Patterson, R.; Iwamoto, S.; Shiomi, J.; Shimamura, K.

2018-06-01

Phonon-phonon scattering dominates the thermal properties in nonmetallic materials, and it directly influences device performance in applications. The understanding of the scattering has been progressing using computational approaches, and the direct and systematic observation of phonon modes that include momentum dependences is desirable. We report experimental data on the phonon dispersion curves and lifetimes in an epitaxially grown ScN film using inelastic x-ray scattering measurements. The momentum dependence of the optical phonon lifetimes is estimated from the spectral width, and the highest-energy phonon mode around the zone center is found to possess a short lifetime of 0.21 ps. A comparison with first-principles calculations shows that our observed phonon lifetimes are quantitatively explained by three-body phonon-phonon interactions.

Structural and optical properties of Sb65Se35-xGex thin films

NASA Astrophysics Data System (ADS)

Saleh, S. A.; Al-Hajry, A.; Ali, H. M.

2011-07-01

Sb65Se35-xGex (x=0-20 at.%) thin films, prepared by the electron beam evaporation technique on ultrasonically cleaned glass substrates at 300 K, were investigated. The amorphous structure of the thin films was confirmed by x-ray diffraction analysis. The structure was deduced from the Raman spectra measured for all germanium contents in the Sb-Se-Ge matrix. The absorption coefficient (α) of the films was determined by optical transmission measurements. The compositional dependence of the optical band gap is discussed in light of topological and chemical ordered network models.

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

NASA Astrophysics Data System (ADS)

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

1994-12-01

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

The calibration of photographic and spectroscopic films: 1: A microscopic analysis of IIaO films. 2: The effects of agitation and soaking on IIaO films. 3: The effects of electric field on IIaO films. 4: The effects of X-ray radiation on IIaO films

NASA Technical Reports Server (NTRS)

Hammond, E. C., Jr.; Peters, K.; Boone, K.

1978-01-01

The grain structure of the emulsion using both reflected and transmission light was examined along with the effects of soaking. The effect of a static charge by a Tesla-coil, and the effects of airport equipment, and dental X-rays on the film were also analyzed.

Studies on RF sputtered (WO{sub 3}){sub 1-x} (V{sub 2}O{sub 5}){sub x} thin films for smart window applications

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

Meenakshi, M.; Perumal, P.; Sivakumar, R.

2016-05-23

V{sub 2}O{sub 5} doped WO{sub 3} targets for RF sputtering thin film deposition were prepared for various compositions. Thin films of (WO{sub 3}){sub 1-x} (V{sub 2}O{sub 5}){sub x} were deposited on to glass substrates using these targets. Structural characteristics of the prepared targets and thin films were studied using X-ray diffraction. Laser Raman studies were carried out on the thin films to confirm the compound formation.

Optimizing soft X-ray NEXAFS spectroscopy in the laboratory

NASA Astrophysics Data System (ADS)

Mantouvalou, I.; Jonas, A.; Witte, K.; Jung, R.; Stiel, H.; Kanngießer, B.

2017-05-01

Near edge X-ray absorption fine structure (NEXAFS) spectroscopy in the soft X-ray range is feasible in the laboratory using laser-produced plasma sources. We present a study using seven different target materials for optimized data analysis. The emission spectra of the materials with atomic numbers ranging from Z = 6 to Z = 79 show distinct differences, rendering the adapted selection of a suitable target material for specialized experiments feasible. For NEXAFS spectroscopy a 112.5 nm thick polyimide film is investigated as a reference exemplifying the superiority of quasi-continuum like emission spectra.

Thickness determination of thin solid films by angle-resolved X-ray fluorescence spectrometry using monochromatized synchrotron radiation

NASA Astrophysics Data System (ADS)

Schmitt, W.; Drotbohm, P.; Rothe, J.; Hormes, J.; Ottermann, C. R.; Bange, K.

1995-05-01

Thickness measurements by the method of angle-resolved, self-ratio X-ray fluorescence spectrometry (AR/SR/XFS) have been carried out on thin solid films using monochromatized synchrotron radiation at the Bonn storage ring ELSA. Synchrotron radiation was monochromatized by means of a double-crystal monochromator and fluorescence radiation was detected by a Si(Li) semiconductor detector. The results for sample systems consisting of Au on Si, Cr on SiO2 and TiO2 on alkali-free glass are very satisfactory and agree well with results obtained by other methods.

Development of a spectro-electrochemical cell for soft X-ray photon-in photon-out spectroscopy

NASA Astrophysics Data System (ADS)

Ishihara, Tomoko; Tokushima, Takashi; Horikawa, Yuka; Kato, Masaru; Yagi, Ichizo

2017-10-01

We developed a spectro-electrochemical cell for X-ray absorption and X-ray emission spectroscopy, which are element-specific methods to study local electronic structures in the soft X-ray region. In the usual electrochemical measurement setup, the electrode is placed in solution, and the surface/interface region of the electrode is not normally accessible by soft X-rays that have low penetration depth in liquids. To realize soft X-ray observation of electrochemical reactions, a 15-nm-thick Pt layer was deposited on a 150-nm-thick film window with an adhesive 3-nm-thick Ti layer for use as both the working electrode and the separator window between vacuum and a sample liquid under atmospheric pressure. The designed three-electrode electrochemical cell consists of a Pt film on a SiC window, a platinized Pt wire, and a commercial Ag|AgCl electrode as the working, counter, and reference electrodes, respectively. The functionality of the cell was tested by cyclic voltammetry and X-ray absorption and emission spectroscopy. As a demonstration, the electroplating of Pb on the Pt/SiC membrane window was measured by X-ray absorption and real-time monitoring of fluorescence intensity at the O 1s excitation.

Simultaneous Neutron and X-ray Tomography for Quantitative analysis of Geological Samples

NASA Astrophysics Data System (ADS)

LaManna, J.; Hussey, D. S.; Baltic, E.; Jacobson, D. L.

2016-12-01

Multiphase flow is a critical area of research for shale gas, oil recovery, underground CO2 sequestration, geothermal power, and aquifer management. It is critical to understand the porous structure of the geological formations in addition to the fluid/pore and fluid/fluid interactions. Difficulties for analyzing flow characteristics of rock cores are in obtaining 3D distribution information on the fluid flow and maintaining the cores in a state for other analysis methods. Two powerful non-destructive methods for obtaining 3D structural and compositional information are X-ray and neutron tomography. X-ray tomography produces information on density and structure while neutrons excel at acquiring the liquid phase and produces compositional information. These two methods can offer strong complementary information but are typically conducted at separate times and often at different facilities. This poses issues for obtaining dynamic and stochastic information as the sample will change between analysis modes. To address this, NIST has developed a system that allows for multimodal, simultaneous tomography using thermal neutrons and X-rays by placing a 90 keVp micro-focus X-ray tube 90° to the neutron beam. High pressure core holders that simulate underground conditions have been developed to facilitate simultaneous tomography. These cells allow for the control of confining pressure, axial load, temperature, and fluid flow through the core. This talk will give an overview the simultaneous neutron and x-ray tomography capabilities at NIST, the benefits of multimodal imaging, environmental equipment for geology studies, and several case studies that have been conducted at NIST.

Printable organometallic perovskite enables large-area, low-dose X-ray imaging

NASA Astrophysics Data System (ADS)

Kim, Yong Churl; Kim, Kwang Hee; Son, Dae-Yong; Jeong, Dong-Nyuk; Seo, Ja-Young; Choi, Yeong Suk; Han, In Taek; Lee, Sang Yoon; Park, Nam-Gyu

2017-10-01

Medical X-ray imaging procedures require digital flat detectors operating at low doses to reduce radiation health risks. Solution-processed organic-inorganic hybrid perovskites have characteristics that make them good candidates for the photoconductive layer of such sensitive detectors. However, such detectors have not yet been built on thin-film transistor arrays because it has been difficult to prepare thick perovskite films (more than a few hundred micrometres) over large areas (a detector is typically 50 centimetres by 50 centimetres). We report here an all-solution-based (in contrast to conventional vacuum processing) synthetic route to producing printable polycrystalline perovskites with sharply faceted large grains having morphologies and optoelectronic properties comparable to those of single crystals. High sensitivities of up to 11 microcoulombs per air KERMA of milligray per square centimetre (μC mGyair-1 cm-2) are achieved under irradiation with a 100-kilovolt bremsstrahlung source, which are at least one order of magnitude higher than the sensitivities achieved with currently used amorphous selenium or thallium-doped cesium iodide detectors. We demonstrate X-ray imaging in a conventional thin-film transistor substrate by embedding an 830-micrometre-thick perovskite film and an additional two interlayers of polymer/perovskite composites to provide conformal interfaces between perovskite films and electrodes that control dark currents and temporal charge carrier transportation. Such an all-solution-based perovskite detector could enable low-dose X-ray imaging, and could also be used in photoconductive devices for radiation imaging, sensing and energy harvesting.

Printable organometallic perovskite enables large-area, low-dose X-ray imaging.

PubMed

Kim, Yong Churl; Kim, Kwang Hee; Son, Dae-Yong; Jeong, Dong-Nyuk; Seo, Ja-Young; Choi, Yeong Suk; Han, In Taek; Lee, Sang Yoon; Park, Nam-Gyu

2017-10-04

Medical X-ray imaging procedures require digital flat detectors operating at low doses to reduce radiation health risks. Solution-processed organic-inorganic hybrid perovskites have characteristics that make them good candidates for the photoconductive layer of such sensitive detectors. However, such detectors have not yet been built on thin-film transistor arrays because it has been difficult to prepare thick perovskite films (more than a few hundred micrometres) over large areas (a detector is typically 50 centimetres by 50 centimetres). We report here an all-solution-based (in contrast to conventional vacuum processing) synthetic route to producing printable polycrystalline perovskites with sharply faceted large grains having morphologies and optoelectronic properties comparable to those of single crystals. High sensitivities of up to 11 microcoulombs per air KERMA of milligray per square centimetre (μC mGy air -1 cm -2 ) are achieved under irradiation with a 100-kilovolt bremsstrahlung source, which are at least one order of magnitude higher than the sensitivities achieved with currently used amorphous selenium or thallium-doped cesium iodide detectors. We demonstrate X-ray imaging in a conventional thin-film transistor substrate by embedding an 830-micrometre-thick perovskite film and an additional two interlayers of polymer/perovskite composites to provide conformal interfaces between perovskite films and electrodes that control dark currents and temporal charge carrier transportation. Such an all-solution-based perovskite detector could enable low-dose X-ray imaging, and could also be used in photoconductive devices for radiation imaging, sensing and energy harvesting.

GIXSGUI : a MATLAB toolbox for grazing-incidence X-ray scattering data visualization and reduction, and indexing of buried three-dimensional periodic nanostructured films

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

Jiang, Zhang

GIXSGUIis a MATLAB toolbox that offers both a graphical user interface and script-based access to visualize and process grazing-incidence X-ray scattering data from nanostructures on surfaces and in thin films. It provides routine surface scattering data reduction methods such as geometric correction, one-dimensional intensity linecut, two-dimensional intensity reshapingetc. Three-dimensional indexing is also implemented to determine the space group and lattice parameters of buried organized nanoscopic structures in supported thin films.

Evaluation of detector dynamic range in the x-ray exposure domain in mammography: a comparison between film-screen and flat panel detector systems.

PubMed

Cooper, Virgil N; Oshiro, Thomas; Cagnon, Christopher H; Bassett, Lawrence W; McLeod-Stockmann, Tyler M; Bezrukiy, Nikita V

2003-10-01

Digital detectors in mammography have wide dynamic range in addition to the benefit of decoupled acquisition and display. How wide the dynamic range is and how it compares to film-screen systems in the clinical x-ray exposure domain are unclear. In this work, we compare the effective dynamic ranges of film-screen and flat panel mammography systems, along with the dynamic ranges of their component image receptors in the clinical x-ray exposure domain. An ACR mammography phantom was imaged using variable mAs (exposure) values for both systems. The dynamic range of the contrast-limited film-screen system was defined as that ratio of mAs (exposure) values for a 26 kVp Mo/Mo (HVL=0.34 mm Al) beam that yielded passing phantom scores. The same approach was done for the noise-limited digital system. Data from three independent observers delineated a useful phantom background optical density range of 1.27 to 2.63, which corresponded to a dynamic range of 2.3 +/- 0.53. The digital system had a dynamic range of 9.9 +/- 1.8, which was wider than the film-screen system (p<0.02). The dynamic range of the film-screen system was limited by the dynamic range of the film. The digital detector, on the other hand, had an estimated dynamic range of 42, which was wider than the dynamic range of the digital system in its entirety by a factor of 4. The generator/tube combination was the limiting factor in determining the digital system's dynamic range.

Transmission type flat-panel X-ray source using ZnO nanowire field emitters

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

Chen, Daokun; Song, Xiaomeng; Zhang, Zhipeng

2015-12-14

A transmission type flat-panel X-ray source in diode structure was fabricated. Large-scale patterned ZnO nanowires grown on a glass substrate by thermal oxidation were utilized as field emitters, and tungsten thin film coated on silica glass was used as the transmission anode. Uniform distribution of X-ray generation was achieved, which benefited from the uniform electron emission from ZnO nanowires. Self-ballasting effect induced by the intrinsic resistance of ZnO nanowire and decreasing of screening effect caused by patterned emitters account for the uniform emission. Characteristic X-ray peaks of W-L lines and bremsstrahlung X-rays have been observed under anode voltages at amore » range of 18–20 kV, the latter of which were the dominant X-ray signals. High-resolution X-ray images with spatial resolution less than 25 μm were obtained by the flat-panel X-ray source. The high resolution was attributed to the small divergence angle of the emitted X-rays from the transmission X-ray source.« less

Effects of deposition temperatures on structure and physical properties of Cd 1-xZn xTe films prepared by RF magnetron sputtering

NASA Astrophysics Data System (ADS)

Zeng, Dongmei; Jie, Wanqi; Zhou, Hai; Yang, Yingge

2010-02-01

Cd 1-xZn xTe films were deposited by RF magnetron sputtering from Cd 0.9Zn 0.1Te crystals target at different substrate temperatures (100-400 °C). The effects of the deposition temperature on structure and physical properties of Cd 1-xZn xTe films have been studied using X-ray diffraction (XRD), step profilometer, atomic force microscopy (AFM), ultraviolet spectrophotometer and Hall effect measurements. X-ray studies suggest that the deposited films were polycrystalline with preferential (1 1 1) orientation. AFM micrographs show that the grain size was changed from 50 to 250 nm with the increase of deposition temperatures, the increased grain size may result from kinetic factors during sputtering growth. The optical transmission data indicate that shallow absorption edge occurs in the range of 744-835 nm and that the optical absorption coefficient is varied with the increase of deposition temperatures. In Hall Effect measurements, the sheet resistivities of the deposited films are 3.2×10 8, 3.0×10 8, 1.9×10 8 and 1.1×10 8 Ohm/sq, which were decreased with the increase of substrate temperatures. Analysis of the resistivity of films depended on the substrate temperatures is discussed.

Transport Measurements and Synchrotron-Based X-Ray Absorption Spectroscopy of Iron Silicon Germanide Grown by Molecular Beam Epitaxy

NASA Astrophysics Data System (ADS)

Elmarhoumi, Nader; Cottier, Ryan; Merchan, Greg; Roy, Amitava; Lohn, Chris; Geisler, Heike; Ventrice, Carl, Jr.; Golding, Terry

2009-03-01

Some of the iron-based metal silicide and germanide phases have been predicted to be direct band gap semiconductors. Therefore, they show promise for use as optoelectronic materials. We have used synchrotron-based x-ray absorption spectroscopy to study the structure of iron silicon germanide films grown by molecular beam epitaxy. A series of Fe(Si1-xGex)2 thin films (2000 -- 8000å) with a nominal Ge concentration of up to x = 0.04 have been grown. X-ray absorption near edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) measurements have been performed on the films. The nearest neighbor co-ordination corresponding to the β-FeSi2 phase of iron silicide provides the best fit with the EXAFS data. Temperature dependent (20 < T < 350 K) magneto transport measurements were done on the Fe(Si1-xGex)2 thin films via Van Der Paw (VDP) Hall configuration using a 0.5-1T magnetic field and a current of 10-200 μA through indium ohmic contacts, the Hall coefficient was calculated. Results suggest semiconducting behavior of the films which is consistent with the EXAFS results.

Quest for ultrahigh resolution in X-ray optics. [for solar astronomy

NASA Technical Reports Server (NTRS)

Davis, J. M.; Krieger, A. S.; Silk, J. K.; Chase, R. C.

1979-01-01

A program of solar X-ray astronomy using grazing incidence optics has culminated in X-ray images of the corona having one arc second spatial resolution. These images have demonstrated that, in general, X-ray optics can be fabricated to their specifications and can provide the level of resolution for which they are designed. Several aspects of these programs relating to the performance of X-ray optics in regard to resolution, including the point response function, the variation of resolution with off-axis position and the recognition that nearly all solar X-ray images have been film limited, are discussed. By extending the experience gained on this and other programs it is clearly possible to design and fabricate X-ray optics with sub arc sec resolution. The performance required to meet the scientific objectives for the remainder of the century are discussed in relation to AXIO, an Advanced X-Ray Imaging Observatory for solar observations which is proposed for flight on the Space Shuttle. Several configurations of AXIO are described, each of which would be a major step in the quest for ultrahigh-resolution observations.

Surface Termination Conversion during SrTiO3 Thin Film Growth Revealed by X-ray Photoelectron Spectroscopy

PubMed Central

Baeumer, Christoph; Xu, Chencheng; Gunkel, Felix; Raab, Nicolas; Heinen, Ronja Anika; Koehl, Annemarie; Dittmann, Regina

2015-01-01

Emerging electrical and magnetic properties of oxide interfaces are often dominated by the termination and stoichiometry of substrates and thin films, which depend critically on the growth conditions. Currently, these quantities have to be measured separately with different sophisticated techniques. This report will demonstrate that the analysis of angle dependent X-ray photoelectron intensity ratios provides a unique tool to determine both termination and stoichiometry simultaneously in a straightforward experiment. Fitting the experimental angle dependence with a simple analytical model directly yields both values. The model is calibrated through the determination of the termination of SrTiO3 single crystals after systematic pulsed laser deposition of sub-monolayer thin films of SrO. We then use the model to demonstrate that during homoepitaxial SrTiO3 growth, excess Sr cations are consumed in a self-organized surface termination conversion before cation defects are incorporated into the film. We show that this termination conversion results in insulating properties of interfaces between polar perovskites and SrTiO3 thin films. These insights about oxide thin film growth can be utilized for interface engineering of oxide heterostructures. In particular, they suggest a recipe for obtaining two-dimensional electron gases at thin film interfaces: SrTiO3 should be deposited slightly Ti-rich to conserve the TiO2-termination. PMID:26189436

Orientational behavior of thin films of poly(3-methylthiophene) on platinium: A FTIR and near edge x-ray absorption fine structure (NEXAFS) study

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

Yang, X.Q.; Chen, J.; Hale, P.D.

1988-01-01

Near edge x-ray absorption fine structure (NEXAFS) and infrared reflection-absorption spectroscopy (IRRAS) have been used to study the orientational behavior of thin films of poly(3-methylthiophene) electrochemically polymerized on a platinum surface. Clear orientational effects, with the thiophene rings predominantly oriented parallel to the platinum surface, were observed when the thickness of the polymer films were within a few hundred /angstrom/A. It was found that more highly ordered films were produced at lower polymerization potential (1.4V vs SCE) than at higher potential (1.8V vs SCE). 5 refs., 4 figs., 2 tabs.

X-Ray Polarization from High Mass X-Ray Binaries

NASA Technical Reports Server (NTRS)

Kallman, T.; Dorodnitsyn, A.; Blondin, J.

2015-01-01

X-ray astronomy allows study of objects which may be associated with compact objects, i.e. neutron stars or black holes, and also may contain strong magnetic fields. Such objects are categorically non-spherical, and likely non-circular when projected on the sky. Polarization allows study of such geometric effects, and X-ray polarimetry is likely to become feasible for a significant number of sources in the future. A class of potential targets for future X-ray polarization observations is the high mass X-ray binaries (HMXBs), which consist of a compact object in orbit with an early type star. In this paper we show that X-ray polarization from HMXBs has a distinct signature which depends on the source inclination and orbital phase. The presence of the X-ray source displaced from the star creates linear polarization even if the primary wind is spherically symmetric whenever the system is viewed away from conjunction. Direct X-rays dilute this polarization whenever the X-ray source is not eclipsed; at mid-eclipse the net polarization is expected to be small or zero if the wind is circularly symmetric around the line of centers. Resonance line scattering increases the scattering fraction, often by large factors, over the energy band spanned by resonance lines. Real winds are not expected to be spherically symmetric, or circularly symmetric around the line of centers, owing to the combined effects of the compact object gravity and ionization on the wind hydrodynamics. A sample calculation shows that this creates polarization fractions ranging up to tens of percent at mid-eclipse.

Ultra-fast LuI{sub 3}:Ce scintillators for hard x-ray imaging

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

Marton, Zsolt, E-mail: zmarton@rmdinc.com; Miller, Stuart R.; Ovechkina, Elena

We have developed ultra-fast cerium-coped lutetium-iodide (LuI{sub 3}:Ce) films thermally evaporated as polycrystalline, structured scintillator using hot wall epitaxy (HWE) method. The films have shown a 13 ns decay compared to the 28 ns reported for crystals. The fast speed coupled with its high density (∼5.6 g/cm{sup 3}), high effective atomic number (59.7), and the fact that it can be vapor deposited in a columnar form makes LuI{sub 3}:Ce an attractive candidate for high frame rate, high-resolution, hard X-ray imaging. In crystal form, LuI{sub 3}:Ce has demonstrated bright (>100,000 photons/MeV) green (540 nm) emission, which is well matched to commercialmore » CCD/CMOS sensors and is critical for maintaining high signal to noise ratio in light starved applications. Here, we report on the scintillation properties of films and those for corresponding crystalline material. The vapor grown films were integrated into a high-speed CMOS imager to demonstrate high-speed radiography capability. The films were also tested at Advanced Photon Source, Argonne National Laboratory beamline 1-ID under hard X-ray irradiation. The data show a factor of four higher efficiency than the reference LuAG:Ce scintillators, high image quality, and linearity of scintillation response over a wide energy range. The films were employed to perform hard X-ray microtomography, the results of which will also be discussed.« less

Near Edge X-Ray Absorption and X-Ray Photoelectron Diffraction Studies of the Structural Environment of Ge-Si Systems

NASA Astrophysics Data System (ADS)

Castrucci, P.; Gunnella, R.; Pinto, N.; Bernardini, R.; de Crescenzi, M.; Sacchi, M.

Near edge X-ray absorption spectroscopy (XAS), X-ray photoelectron diffraction (XPD) and Auger electron diffraction (AED) are powerful techniques for the qualitative study of the structural and electronic properties of several systems. The recent development of a multiple scattering approach to simulating experimental spectra opened a friendly way to the study of structural environments of solids and surfaces. This article reviews recent X-ray absorption experiments using synchrotron radiation which were performed at Ge L edges and core level electron diffraction measurements obtained using a traditional X-ray source from Ge core levels for ultrathin Ge films deposited on silicon substrates. Thermodynamics and surface reconstruction have been found to play a crucial role in the first stages of Ge growth on Si(001) and Si(111) surfaces. Both techniques show the occurrence of intermixing processes even for room-temperature-grown Ge/Si(001) samples and give a straightforward measurement of the overlayer tetragonal distortion. The effects of Sb as a surfactant on the Ge/Si(001) interface have also been investigated. In this case, evidence of layer-by-layer growth of the fully strained Ge overlayer with a reduced intermixing is obtained when one monolayer of Sb is predeposited on the surface.

Be/X-ray Binary Science for Future X-ray Timing Missions

NASA Technical Reports Server (NTRS)

Wilson-Hodge, Colleen A.

2011-01-01

For future missions, the Be/X-ray binary community needs to clearly define our science priorities for the future to advocate for their inclusion in future missions. In this talk, I will describe current designs for two potential future missions and Be X-ray binary science enabled by these designs. The Large Observatory For X-ray Timing (LOFT) is an X-ray timing mission selected in February 2011 for the assessment phase from the 2010 ESA M3 call for proposals. The Advanced X-ray Timing ARray (AXTAR) is a NASA explorer concept X-ray timing mission. This talk is intended to initiate discussions of our science priorities for the future.

X-ray standing wave analysis of nanostructures using partially coherent radiation

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

Tiwari, M. K., E-mail: mktiwari@rrcat.gov.in; Das, Gangadhar; Bedzyk, M. J.

2015-09-07

The effect of longitudinal (or temporal) coherence on total reflection assisted x-ray standing wave (TR-XSW) analysis of nanoscale materials is quantitatively demonstrated by showing how the XSW fringe visibility can be strongly damped by decreasing the spectral resolution of the incident x-ray beam. The correction for nonzero wavelength dispersion (δλ ≠ 0) of the incident x-ray wave field is accounted for in the model computations of TR-XSW assisted angle dependent fluorescence yields of the nanostructure coatings on x-ray mirror surfaces. Given examples include 90 nm diameter Au nanospheres deposited on a Si(100) surface and a 3 nm thick Zn layer trapped on top amore » 100 nm Langmuir-Blodgett film coating on a Au mirror surface. Present method opens up important applications, such as enabling XSW studies of large dimensioned nanostructures using conventional laboratory based partially coherent x-ray sources.« less

Abdomen X-Ray (Radiography)

MedlinePlus

... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Abdomen Abdominal x-ray uses a ... of an abdominal x-ray? What is abdominal x-ray? An x-ray (radiograph) is a noninvasive ...

A direct correlation of x-ray diffraction orientation distributions to the in-plane stiffness of semi-crystalline organic semiconducting films

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

Zhao, Bingxiao; Awartani, Omar; O'Connor, Brendan

2016-05-02

Large charge mobilities of semi-crystalline organic semiconducting films could be obtained by mechanically aligning the material phases of the film with the loading axis. A key element is to utilize the inherent stiffness of the material for optimal or desired alignment. However, experimentally determining the moduli of semi-crystalline organic thin films for different loading directions is difficult, if not impossible, due to film thickness and material anisotropy. In this paper, we address these challenges by presenting an approach based on combining a composite mechanics stiffness orientation formulation with a Gaussian statistical distribution to directly estimate the in-plane stiffness (transverse isotropy)more » of aligned semi-crystalline polymer films based on crystalline orientation distributions obtained by X-ray diffraction experimentally at different applied strains. Our predicted results indicate that the in-plane stiffness of an annealing film was initially isotropic, and then it evolved to transverse isotropy with increasing mechanical strains. This study underscores the significance of accounting for the crystalline orientation distributions of the film to obtain an accurate understanding and prediction of the elastic anisotropy of semi-crystalline polymer films.« less

A search for X-ray polarization in cosmic X-ray sources. [binary X-ray sources and supernovae remnants

NASA Technical Reports Server (NTRS)

Hughes, J. P.; Long, K. S.; Novick, R.

1983-01-01

Fifteen strong X-ray sources were observed by the X-ray polarimeters on board the OSO-8 satellite from 1975 to 1978. The final results of this search for X-ray polarization in cosmic sources are presented in the form of upper limits for the ten sources which are discussed elsewhere. These limits in all cases are consistent with a thermal origin for the X-ray emission.

Indirect X-ray Detectors Based on Inkjet-Printed Photodetectors with a Screen-Printed Scintillator Layer.

PubMed

Oliveira, Juliana; Correia, Vitor; Sowade, Enrico; Etxebarria, Ikerne; Rodriguez, Raul D; Mitra, Kalyan Y; Baumann, Reinhard R; Lanceros-Mendez, Senentxu

2018-04-18

Organic photodetectors (PDs) based on printing technologies will allow to expand the current field of PD applications toward large-area and flexible applications in areas such as medical imaging, security, and quality control, among others. Inkjet printing is a powerful digital tool for the deposition of smart and functional materials on various substrates, allowing the development of electronic devices such as PDs on various substrates. In this work, inkjet-printed PD arrays, based on the organic thin-film transistor architecture, have been developed and applied for the indirect detection of X-ray radiation using a scintillator ink as an X-ray absorber. The >90% increase of the photocurrent of the PDs under X-ray radiation, from about 53 nA without the scintillator film to about 102 nA with the scintillator located on top of the PD, proves the suitability of the developed printed device for X-ray detection applications.

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

NASA Technical Reports Server (NTRS)

Tavani, Marco

1998-01-01

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

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

NASA Technical Reports Server (NTRS)

Halpern, Jules P.; Kaaret, Philip

1999-01-01

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

Lumbosacral spine x-ray

MedlinePlus

X-ray - lumbosacral spine; X-ray - lower spine ... The test is done in a hospital x-ray department or your health care provider's office by an x-ray technician. You will be asked to lie on the x-ray ...

Agreement and reading time for differently-priced devices for the digital capture of X-ray films.

PubMed

Salazar, Antonio José; Camacho, Juan Camilo; Aguirre, Diego Andrés

2012-03-01

We assessed the reliability of three digital capture devices: a film digitizer (which cost US $15,000), a flat-bed scanner (US $1800) and a digital camera (US $450). Reliability was measured as the agreement between six observers when reading images acquired from a single device and also in terms of the pair-device agreement. The images were 136 chest X-ray cases. The variables measured were the interstitial opacities distribution, interstitial patterns, nodule size and percentage pneumothorax size. The agreement between the six readers when reading images acquired from a single device was similar for the three devices. The pair-device agreements were moderate for all variables. There were significant differences in reading-time between devices: the mean reading-time for the film digitizer was 93 s, it was 59 s for the flat-bed scanner and 70 s for the digital camera. Despite the differences in their cost, there were no substantial differences in the performance of the three devices.

X-ray spectroscopy study of electronic structure of laser-irradiated Au nanoparticles in a silica film

NASA Astrophysics Data System (ADS)

Jonnard, P.; Bercegol, H.; Lamaignère, L.; Morreeuw, J.-P.; Rullier, J.-L.; Cottancin, E.; Pellarin, M.

2005-03-01

The electronic structure of gold nanoparticles embedded in a silica film is studied, both before and after irradiation at 355nm by a laser. The Au 5d occupied valence states are observed by x-ray emission spectroscopy. They show that before irradiation the gold atoms are in metallic states within the nanoparticles. After irradiation with a fluence of 0.5J/cm2, it is found that gold valence states are close to those of a metal-poor gold silicide; thanks to a comparison of the experimental Au 5d states with the calculated ones for gold silicides using the density-functional theory. The formation of such a compound is driven by the diffusion of the gold atoms into the silica film upon the laser irradiation. At higher fluence, 1J/cm2, we find a higher percentage of metallic gold that could be attributed to annealing in the silica matrix.

The Dram As An X-Ray Sensor

NASA Astrophysics Data System (ADS)

Jacobs, Alan M.; Cox, John D.; Juang, Yi-Shung

1987-01-01

A solid-state digital x-ray detector is described which can replace high resolution film in industrial radiography and has potential for application in some medical imaging. Because of the 10 micron pixel pitch on the sensor, contact magnification radiology is possible and is demonstrated. Methods for frame speed increase and integration of sensor to a large format are discussed.

X-ray ptychography

NASA Astrophysics Data System (ADS)

Pfeiffer, Franz

2018-01-01

X-ray ptychographic microscopy combines the advantages of raster scanning X-ray microscopy with the more recently developed techniques of coherent diffraction imaging. It is limited neither by the fabricational challenges associated with X-ray optics nor by the requirements of isolated specimen preparation, and offers in principle wavelength-limited resolution, as well as stable access and solution to the phase problem. In this Review, we discuss the basic principles of X-ray ptychography and summarize the main milestones in the evolution of X-ray ptychographic microscopy and tomography over the past ten years, since its first demonstration with X-rays. We also highlight the potential for applications in the life and materials sciences, and discuss the latest advanced concepts and probable future developments.

Deviations from Vegard's law in semiconductor thin films measured with X-ray diffraction and Rutherford backscattering: The Ge1-ySny and Ge1-xSix cases

NASA Astrophysics Data System (ADS)

Xu, Chi; Senaratne, Charutha L.; Culbertson, Robert J.; Kouvetakis, John; Menéndez, José

2017-09-01

The compositional dependence of the lattice parameter in Ge1-ySny alloys has been determined from combined X-ray diffraction and Rutherford Backscattering (RBS) measurements of a large set of epitaxial films with compositions in the 0 < y < 0.14 range. In view of contradictory prior results, a critical analysis of this method has been carried out, with emphasis on nonlinear elasticity corrections and systematic errors in popular RBS simulation codes. The approach followed is validated by showing that measurements of Ge1-xSix films yield a bowing parameter θGeSi =-0.0253(30) Å, in excellent agreement with the classic work by Dismukes. When the same methodology is applied to Ge1-ySny alloy films, it is found that the bowing parameter θGeSn is zero within experimental error, so that the system follows Vegard's law. This is in qualitative agreement with ab initio theory, but the value of the experimental bowing parameter is significantly smaller than the theoretical prediction. Possible reasons for this discrepancy are discussed in detail.

Band gap states in nanocrystalline WO3 thin films studied by soft x-ray spectroscopy and optical spectrophotometry.

PubMed

Johansson, M B; Kristiansen, P T; Duda, L; Niklasson, G A; Österlund, L

2016-11-30

Nanocrystalline tungsten trioxide (WO3) thin films prepared by DC magnetron sputtering have been studied using soft x-ray spectroscopy and optical spectrophotometry. Resonant inelastic x-ray scattering (RIXS) measurements reveal band gap states in sub-stoichiometric γ-WO3-x with x  =  0.001-0.005. The energy positions of these states are in good agreement with recently reported density functional calculations. The results were compared with optical absorption measurements in the near infrared spectral region. An optical absorption peak at 0.74 eV is assigned to intervalence transfer of polarons between W sites. A less prominent peak at energies between 0.96 and 1.16 eV is assigned to electron excitation of oxygen vacancies. The latter results are supported by RIXS measurements, where an energy loss in this energy range was observed, and this suggests that electron transfer processes involving transitions from oxygen vacancy states can be observed in RIXS. Our results have implications for the interpretation of optical properties of WO3, and the optical transitions close to the band gap, which are important in photocatalytic and photoelectrochemical applications.

Investigation of ZrO x /ZrC-ZrN/Zr thin-film structural evolution and their degradation using X-ray diffraction and Raman spectrometry

NASA Astrophysics Data System (ADS)

Usmani, B.; Vijay, V.; Chhibber, R.; Dixit, A.

2016-11-01

The thin-film structures of DC/FR magnetron-sputtered ZrO x /ZrC-ZrN/Zr tandem solar-selective coatings are investigated using X-ray diffraction and room-temperature Raman spectroscopic measurements. These studies suggest that the major contribution is coming from h-ZrN0.28, c-ZrC, h-Zr3C2 crystallographic phases in ZrN-ZrC absorber layer, in conjunction with mixed ZrO x crystallographic phases. The change in structure for thermally annealed samples has been examined and observed that cubic and hexagonal ZrO x phase converted partially into tetragonal and monoclinic ZrO x phases, whereas hexagonal and cubic ZrN phases, from absorber layer, have not been observed for these thermally treated samples in air. These studies suggest that thermal treatment may lead to the loss of ZrN phase in absorber, degrading the thermal response for the desired wavelength range in open ambient conditions in contrast to vacuum conditions.

Improved adhesion of Ni films on X-ray damaged polytetrafluoroethylene

NASA Technical Reports Server (NTRS)

Wheeler, D. R.; Pepper, S. V.

1981-01-01

The considered investigation shows that the adhesion of evaporated Ni on polytetrafluoroethylene (PTFE) is enhanced by irradiating the PTFE surface prior to evaporation. Evidence obtained with the aid of X-ray photoelectron spectroscopy is presented concerning the association of the enhanced adhesion with an interfacial chemical reaction. Evaporated Ni clearly adheres better to the X-ray damaged PTFE surface than to the undamaged surface. There is evidence that the improved adhesion is not related to the Ni-C bond, but rather to the NiF2. A possible mechanism which may be consistent with the data is the formation of a F-Ni-C complex, where C is a member of the polymer chain.

Toward broad-band x-ray detected ferromagnetic resonance in longitudinal geometry

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

Ollefs, K.; European Synchrotron Radiation Facility; Meckenstock, R.

2015-06-14

An ultrahigh-vacuum-compatible setup for broad-band X-ray detected ferromagnetic resonance (XFMR) in longitudinal geometry is introduced which relies on a low-power, continuous-wave excitation of the ferromagnetic sample. A simultaneous detection of the conventional ferromagnetic resonance via measuring the reflected microwave power and the XFMR signal of the X-ray absorption is possible. First experiments on the Fe and Co L{sub 3}-edges of a permalloy film covered with Co nanostripes as well as the Fe and Ni K-edges of a permalloy film are presented and discussed. Two different XFMR signals are found, one of which is independent of the photon energy and thereforemore » does not provide element-selective information. The other much weaker signal is element-selective, and the dynamic magnetic properties could be detected for Fe and Co separately. The dependence of the latter XFMR signal on the photon helicity of the synchrotron light is found to be distinct from the usual x-ray magnetic circular dichroism effect.« less

Efficient modeling of Bragg coherent x-ray nanobeam diffraction

DOE PAGES

Hruszkewycz, S. O.; Holt, M. V.; Allain, M.; ...

2015-07-02

X-ray Bragg diffraction experiments that utilize tightly focused coherent beams produce complicated Bragg diffraction patterns that depend on scattering geometry, characteristics of the sample, and properties of the x-ray focusing optic. In this paper, we use a Fourier-transform-based method of modeling the 2D intensity distribution of a Bragg peak and apply it to the case of thin films illuminated with a Fresnel zone plate in three different Bragg scattering geometries. Finally, the calculations agree well with experimental coherent diffraction patterns, demonstrating that nanodiffraction patterns can be modeled at nonsymmetric Bragg conditions with this approach—a capability critical for advancing nanofocused x-raymore » diffraction microscopy.« less

Nanosecond X-ray Photon Correlation Spectroscopy on Magnetic Skyrmions

DOE PAGES

Seaberg, M. H.; Holladay, B.; Lee, J. C. T.; ...

2017-08-09

We report an X-ray photon correlation spectroscopy method that exploits the recent development of the two-pulse mode at the Linac Coherent Light Source. By using coherent resonant X-ray magnetic scattering, we studied spontaneous fluctuations on nanosecond timescales in thin films of multilayered Fe/Gd that exhibit ordered stripe and skyrmion lattice phases. The correlation time of the fluctuations was found to differ between the skyrmion phase and near the stripe-skyrmion boundary. As a result, this technique will enable a significant new area of research on the study of equilibrium fluctuations in condensed matter.

Nanosecond X-ray Photon Correlation Spectroscopy on Magnetic Skyrmions

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

Seaberg, M. H.; Holladay, B.; Lee, J. C. T.

We report an X-ray photon correlation spectroscopy method that exploits the recent development of the two-pulse mode at the Linac Coherent Light Source. By using coherent resonant X-ray magnetic scattering, we studied spontaneous fluctuations on nanosecond timescales in thin films of multilayered Fe/Gd that exhibit ordered stripe and skyrmion lattice phases. The correlation time of the fluctuations was found to differ between the skyrmion phase and near the stripe-skyrmion boundary. As a result, this technique will enable a significant new area of research on the study of equilibrium fluctuations in condensed matter.

Does a chest x-ray alter the management of new patients attending a geriatric day hospital?

PubMed

Logan, J A; Vallance, R; Williams, B O; Paul, H

1997-01-01

Studies have suggested that routine chest x-ray is never indicated but all new attenders at our day hospitals have a chest x-ray carried out. Our aim was to determine if this investigation altered the clinical management of patients and to try to select those patients in whom a chest x-ray is indicated. A prospective study was carried out over a 7 month period from February to September 1995. All new patients had cardiorespiratory symptoms/signs documented and a management plan made. A chest x-ray was then carried out and change in management as a result of the x-ray report noted. Knightswood and Drumchapel Geriatric Day Hospitals, West Glasgow University NHS Trust. All new Day Hospital attenders. Of 207 new Day Hospital attenders, 53 had no clinical indication for a chest x-ray and although 70% had an abnormal film in no case was patient management changed as a result of this. A chest x-ray was indicated in 154 patients and of these 114 (74%) had an abnormal film with a resultant change in management in 23 patients (this comprised either a change in drug treatment or a further investigation.) Of those whose management was changed as a result of the x-ray report 61% had respiratory symptoms. We would recommend that chest x-ray should be performed in those patients who have a clear clinical indication and that the diagnostic yield is highest in the presence of respiratory symptoms or signs.

In-Vivo Real-Time X-ray μ-Imaging

NASA Astrophysics Data System (ADS)

Dammer, Jiri; Holy, Tomas; Jakubek, Jan; Jakubek, Martin; Pospisil, Stanislav; Vavrík, Daniel

2007-11-01

The technique of X-ray transmission imaging is available for more than 100 years and it is still one of the fastest and easiest ways how to study the internal structure of living biological samples. The advances in semiconductor technology in last years make possible to fabricate new types of X-ray detectors with direct conversion of interacting X-ray photon to an electric signal. Especially semiconductor pixel detectors seem to be very promising. Compared to the film technique they bring single-quantum and real-time digital information about the studied object with high resolution, high sensitivity and broad dynamic range. These pixel detector-based imaging stand promising as a new tool in the field of small animal imaging, for cancer research and for observation of dynamic processes inside organisms. These detectors open up for instance new possibilities for researchers to perform non-invasive studies of tissue for mutations or pathologies and to monitor disease progression or response to therapy.

Engine materials characterization and damage monitoring by using x ray technologies

NASA Technical Reports Server (NTRS)

Baaklini, George Y.

1993-01-01

on the fracture behavior of composites. Results from one-, three-, five-, and eight-ply ceramic composite specimens show that x ray film radiography can monitor damage accumulation during tensile loading. Matrix cracking, fiber-matrix debonding, fiber bridging, and fiber pullout are imaged throughout the tensile loading of the specimens. In situ film radiography is found to be a practical technique for estimating interfacial shear strength between the silicon carbide fibers and the reaction-bonded silicon nitride matrix. It is concluded that pretest, in situ, and post-test x ray imaging can provide greater understanding of ceramic matrix composite mechanical behavior.

UNDERSTANDING X-RAY STARS:. The Discovery of Binary X-ray Sources

NASA Astrophysics Data System (ADS)

Schreier, E. J.; Tananbaum, H.

2000-09-01

The discovery of binary X-ray sources with UHURU introduced many new concepts to astronomy. It provided the canonical model which explained X-ray emission from a large class of galactic X-ray sources: it confirmed the existence of collapsed objects as the source of intense X-ray emission; showed that such collapsed objects existed in binary systems, with mass accretion as the energy source for the X-ray emission; and provided compelling evidence for the existence of black holes. This model also provided the basis for explaining the power source of AGNs and QSOs. The process of discovery and interpretation also established X-ray astronomy as an essential sub-discipline of astronomy, beginning its incorporation into the mainstream of astronomy.

Determinants of exposure to chemical pollutants in wet X-ray film processing in Iran.

PubMed

Kakooei, Hossein; Ardakani, Mehdi B; Sadighi, Alireza

2007-07-15

The aim of the current study was to measure glutaraldehyde, acetic acid and sulfur dioxide and levels inside wet x-ray processing areas in a developing country and comparing data with those in developed countries. Forty-five radiographers from 10 educational hospitals affiliated to the Tehran University of Medical Sciences (TUMS) in Tehran, Iran participated in this descriptive-analytical study. Exposure to glutaraldehyde (a constituent of developer chemistry), acetic acid (a constituent of fixer chemistry) and sulfur dioxide (a byproduct of sulfites present in both developer and fixer solutions) was measured in all participants as well as area exposure. Average full-shift exposure to glutaraldehyde, acetic acid and sulfur dioxide were 0.0018, 2.65 and 1.64 mg m(-1), respectively. The results showed that the TUMS radiographers full-shift exposures are generally lower than the American Conference of Governmental Industrial Hygienists (ACGIH) recommended levels. The concentration of glutaraldehyde collected by area sampling (darkroom) was almost five times (0.0104 mg m(-3)) greater than taken by personal sampling. Exposure to the chemical pollutants in the currents study were generally higher than in developed countries. Identification of these key exposure determinants is useful in targeting exposure evaluation and controls to reduce developer and fixer chemicals exposures in the radiology departments. Employing of a digital imaging system that do not involve wet x-ray processing of photographic film would be a useful device for radiographers protection.

Determining optimum wavelength of ultraviolet rays to pre-exposure of non-uniformity error correction in Gafchromic EBT2 films

NASA Astrophysics Data System (ADS)

Katsuda, Toshizo; Gotanda, Rumi; Gotanda, Tatsuhiro; Akagawa, Takuya; Tanki, Nobuyoshi; Kuwano, Tadao; Noguchi, Atsushi; Yabunaka, Kouichi

2018-03-01

Gafchromic films have been used to measure X-ray doses in diagnostic radiology such as computed tomography. The double-exposure technique is used to correct non-uniformity error of Gafchromic EBT2 films. Because of the heel effect of diagnostic x-rays, ultraviolet A (UV-A) is intended to be used as a substitute for x-rays. When using a UV-A light-emitting diode (LED), it is necessary to determine the effective optimal UV wavelength for the active layer of Gafchromic EBT2 films. This study evaluated the relation between the increase in color density of Gafchromic EBT2 films and the UV wavelengths. First, to correct non-uniformity, a Gafchromic EBT2 film was pre-irradiated using uniform UV-A radiation for 60 min from a 72-cm distance. Second, the film was irradiated using a UV-LED with a wavelength of 353-410 nm for 60 min from a 5.3-cm distance. The maximum, minimum, and mean ± standard deviation (SD) of pixel values of the subtraction images were evaluated using 0.5 inches of a circular region of interest (ROI). The highest mean ± SD (8915.25 ± 608.86) of the pixel value was obtained at a wavelength of 375 nm. The results indicated that 375 nm is the most effective and sensitive wavelength of UV-A for Gafchromic EBT2 films and that UV-A can be used as a substitute for x-rays in the double-exposure technique.

X-ray binaries

NASA Technical Reports Server (NTRS)

1976-01-01

Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

Nano-metrology: The art of measuring X-ray mirrors with slope errors <100 nrad

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

Alcock, Simon G., E-mail: simon.alcock@diamond.ac.uk; Nistea, Ioana; Sawhney, Kawal

2016-05-15

We present a comprehensive investigation of the systematic and random errors of the nano-metrology instruments used to characterize synchrotron X-ray optics at Diamond Light Source. With experimental skill and careful analysis, we show that these instruments used in combination are capable of measuring state-of-the-art X-ray mirrors. Examples are provided of how Diamond metrology data have helped to achieve slope errors of <100 nrad for optical systems installed on synchrotron beamlines, including: iterative correction of substrates using ion beam figuring and optimal clamping of monochromator grating blanks in their holders. Simulations demonstrate how random noise from the Diamond-NOM’s autocollimator adds intomore » the overall measured value of the mirror’s slope error, and thus predict how many averaged scans are required to accurately characterize different grades of mirror.« less

Skull x-ray

MedlinePlus

X-ray - head; X-ray - skull; Skull radiography; Head x-ray ... Chernecky CC, Berger BJ. Radiography of skull, chest, and cervical spine - diagnostic. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures . 6th ed. ...

Full-field transmission x-ray imaging with confocal polycapillary x-ray optics

PubMed Central

Sun, Tianxi; MacDonald, C. A.

2013-01-01

A transmission x-ray imaging setup based on a confocal combination of a polycapillary focusing x-ray optic followed by a polycapillary collimating x-ray optic was designed and demonstrated to have good resolution, better than the unmagnified pixel size and unlimited by the x-ray tube spot size. This imaging setup has potential application in x-ray imaging for small samples, for example, for histology specimens. PMID:23460760

Generation of flash x-rays using a mercury-anode radiation tube

NASA Astrophysics Data System (ADS)

Oizumi, Teiji; Sato, Eiichi; Sagae, Michiaki; Hayasi, Yasuomi; Tamakawa, Yoshiharu; Yanagisawa, Toru

1993-02-01

The constructions and the radiographic characteristics of a flash x-ray generator having a liquid-anode radiation tube are described. This generator consisted of the following essential components: a high-voltage power supply, a combined ceramic condenser of 10.7 nF, an oil- diffusion pump, an oil circulator, a trigger device, and a flash x-ray tube. The x-ray tube was of a triode and was composed of the following major devices: a mercury anode, a rod-shaped graphite cathode, a trigger electrode made from a copper wire, an x-ray window made from a polyethyleneterephthalate film, and a glass tube body. The ceramic condenser was charged from 40 to 60 kV by a power supply, and the electric charges in the condenser were discharged to the x-ray tube after the triggering. The maximum tube voltage was equivalent to the initial charged voltage of the condenser, and the tube current was less than 0.7 kA. The pulse widths of the flash x rays had values of about 1 microsecond(s) , and the time-integrated x-ray intensity was about 2.4 (mu) C/kg at 0.26 m per pulse with a charged voltage of 60 kV.

X-ray generator

DOEpatents

Dawson, John M.

1976-01-01

Apparatus and method for producing coherent secondary x-rays that are controlled as to direction by illuminating a mixture of high z and low z gases with an intense burst of primary x-rays. The primary x-rays are produced with a laser activated plasma, and these x-rays strip off the electrons of the high z atoms in the lasing medium, while the low z atoms retain their electrons. The neutral atoms transfer electrons to highly excited states of the highly striped high z ions giving an inverted population which produces the desired coherent x-rays. In one embodiment, a laser, light beam provides a laser spark that produces the intense burst of coherent x-rays that illuminates the mixture of high z and low z gases, whereby the high z atoms are stripped while the low z ones are not, giving the desired mixture of highly ionized and neutral atoms. To this end, the laser spark is produced by injecting a laser light beam, or a plurality of beams, into a first gas in a cylindrical container having an adjacent second gas layer co-axial therewith, the laser producing a plasma and the intense primary x-rays in the first gas, and the second gas containing the high and low atomic number elements for receiving the primary x-rays, whereupon the secondary x-rays are produced therein by stripping desired ions in a neutral gas and transfer of electrons to highly excited states of the stripped ions from the unionized atoms. Means for magnetically confining and stabilizing the plasma are disclosed for controlling the direction of the x-rays.

Cross-calibration of Fuji TR image plate and RAR 2492 x-ray film to determine the response of a DITABIS Super Micron image plate scanner

NASA Astrophysics Data System (ADS)

Dunham, G.; Harding, E. C.; Loisel, G. P.; Lake, P. W.; Nielsen-Weber, L. B.

2016-11-01

Fuji TR image plate is frequently used as a replacement detector medium for x-ray imaging and spectroscopy diagnostics at NIF, Omega, and Z facilities. However, the familiar Fuji BAS line of image plate scanners is no longer supported by the industry, and so a replacement scanning system is needed. While the General Electric Typhoon line of scanners could replace the Fuji systems, the shift away from photo stimulated luminescence units to 16-bit grayscale Tag Image File Format (TIFF) leaves a discontinuity when comparing data collected from both systems. For the purposes of quantitative spectroscopy, a known unit of intensity applied to the grayscale values of the TIFF is needed. The DITABIS Super Micron image plate scanning system was tested and shown to potentially rival the resolution and dynamic range of Kodak RAR 2492 x-ray film. However, the absolute sensitivity of the scanner is unknown. In this work, a methodology to cross calibrate Fuji TR image plate and the absolutely calibrated Kodak RAR 2492 x-ray film is presented. Details of the experimental configurations used are included. An energy dependent scale factor to convert Fuji TR IP scanned on a DITABIS Super Micron scanner from 16-bit grayscale TIFF to intensity units (i.e., photons per square micron) is discussed.

Electronic Structure of Tl2Ba2CuO(6+Delta) Epitaxial Films Measured by X-Ray Photoemission

NASA Technical Reports Server (NTRS)

Vasquez, R. P.; Ren, Z. F.; Wang, J. H.

1996-01-01

The valence electronic structure and core levels of Tl2Ba2CuO(6 + delta) (Tl-2201) epitaxial films have been measured with X-ray photoelectron spectroscopy and are compared to those of Tl2Ba2CaCu2O(8 + delta) (Tl-2212). Changes in the Tl-2201 core-level binding energies with oxygen doping are consistent with a change in the chemical potential. Differences between the Tl-2201 and Tl-2212 measured densities of states are consistent with the calculated Cu 3d and Tl 6s partial densities of states.

PREFACE: Exploring surfaces and buried interfaces of functional materials by advanced x-ray and neutron techniques Exploring surfaces and buried interfaces of functional materials by advanced x-ray and neutron techniques

NASA Astrophysics Data System (ADS)

Sakurai, Kenji

2010-12-01

updates on recent progress and global trends in the field. We planned to cover quite a wide area of surface and buried interface science with x-rays and neutrons. Following a great deal of discussion during the editing process, we have decided to change direction. As we intend to publish similar special issues on a frequent basis, we will not insist on editing this issue as systematic and complete collections of research. Many authors decided to write an ordinary research paper rather than an article including systematic accounts. Due to this change in policy, some authors declined to contribute, and the number of papers is now just 12. However, readers will find that the special issue gives an interesting collection of new original research in surface and buried interface studies with x-rays and neutrons. The 12 papers cover the following research topics: (1) polymer analysis by diffuse scattering; (2) discussion of the electrochemical solid--liquid interface by synchrotron x-ray diffraction; (3) analysis of capped nanodots by grazing incidence small-angle x-ray scattering (GISAXS); (4) discussion of the strain distribution in silicon by high-resolution x-ray diffraction; (5) study of mesoporous structures by a combination of x-ray reflectivity and GISAXS; (6) discussion of energy-dispersive x-ray reflectometry and its applications; (7) neutron reflectivity studies on hydrogen terminated silicon interface; (8) the fabrication and performance of a special mirror for water windows; (9) depth selective analysis by total-reflection x-ray diffraction; (10) nanoparticle thin films prepared by a gas deposition technique; (11) discussion of crystal truncation rod (CTR) scattering of semiconductor nanostructures; (12) magnetic structure analysis of thin films by polarized neutron reflectivity. While not discussed in the present special issue, x-ray and neutron techniques have made great progress. The most important steps forward have been in 2D/3D real-space imaging, and realtime

In-situ stress measurement of single and multilayer thin-films used in x-ray astronomy optics applications

NASA Astrophysics Data System (ADS)

Broadway, David M.; Ramsey, Brian D.; O'Dell, Stephen L.; Gurgew, Danielle

2017-09-01

We present in-situ stress measurement results for single and multilayer thin-films deposited by magnetron sputtering. In particular, we report on the influence of the material interfaces on the ensuing stress in both the transient and steady-state regimes of film growth. This behavior is used to determine the appropriate thicknesses of the constituent layers that will result in a net tensile stress in multilayers composed of various material combinations. These multilayers can then be used to compensate the compressive integrated stress in single and multilayer EUV and x-ray optical coatings. The use of multilayers to compensate the integrated stress might be advantageous because, unlike single layers of chromium, the roughness is not expected to increase with the total thickness of the multilayer. In this paper, we demonstrate the technique for W/Si and Mo/Si multilayers and discuss its application to other material combinations.

X-ray lithography masking

NASA Technical Reports Server (NTRS)

Smith, Henry I. (Inventor); Lim, Michael (Inventor); Carter, James (Inventor); Schattenburg, Mark (Inventor)

1998-01-01

X-ray masking apparatus includes a frame having a supporting rim surrounding an x-ray transparent region, a thin membrane of hard inorganic x-ray transparent material attached at its periphery to the supporting rim covering the x-ray transparent region and a layer of x-ray opaque material on the thin membrane inside the x-ray transparent region arranged in a pattern to selectively transmit x-ray energy entering the x-ray transparent region through the membrane to a predetermined image plane separated from the layer by the thin membrane. A method of making the masking apparatus includes depositing back and front layers of hard inorganic x-ray transparent material on front and back surfaces of a substrate, depositing back and front layers of reinforcing material on the back and front layers, respectively, of the hard inorganic x-ray transparent material, removing the material including at least a portion of the substrate and the back layers of an inside region adjacent to the front layer of hard inorganic x-ray transparent material, removing a portion of the front layer of reinforcing material opposite the inside region to expose the surface of the front layer of hard inorganic x-ray transparent material separated from the inside region by the latter front layer, and depositing a layer of x-ray opaque material on the surface of the latter front layer adjacent to the inside region.

Structural and morphological studies on Bi{sub 1-x}Ca{sub x}MnO{sub 3} thin films grown by RF magnetron sputtering

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

Pugazhvadivu, K. S.; Santhiya, M.; Tamilarasan, K., E-mail: dr.k.tamilarasan@gmail.com

2016-05-23

Bi{sub 1-x}Ca{sub x}MnO{sub 3} (0 ≤ X ≤ 0.4) thin films are deposited on n–type Si (100) substrate at 800 °C by RF magnetron sputtering. X-ray diffraction pattern shows that the films are crystallized in monoclinic structure with C2 space group. The crystallite size and induced strain in the prepared films are measured by W-H plot. The cell parameters and texture coefficient of the films are calculated. The surface morphology of the films is examined by atomic force microscope. The study confirms the optimum level of calcium doping is 20 at. % in Bi site of BiMnO{sub 3} film, thesemore » findings pave the way for further research in the Ca modified BiMnO{sub 3} films towards device fabrication.« less

Sinus x-ray

MedlinePlus

Paranasal sinus radiography; X-ray - sinuses ... sinus x-ray is taken in a hospital radiology department. Or the x-ray may be taken ... Brown J, Rout J. ENT, neck, and dental radiology. In: Adam A, Dixon AK, Gillard JH, Schaefer- ...

X-Ray Data Booklet

Science.gov Websites

X-RAY DATA BOOKLET Center for X-ray Optics and Advanced Light Source Lawrence Berkeley National Laboratory Introduction X-Ray Properties of Elements Electron Binding Energies X-Ray Energy Emission Energies Table of X-Ray Properties Synchrotron Radiation Characteristics of Synchrotron Radiation History of X

Elasticity study of textured barium strontium titanate thin films by X-ray diffraction and laser acoustic waves

NASA Astrophysics Data System (ADS)

Chaabani, Anouar; Njeh, Anouar; Donner, Wolfgang; Klein, Andreas; Hédi Ben Ghozlen, Mohamed

2017-05-01

Ba0.65Sr0.35TiO3 (BST) thin films of 300 nm were deposited on Pt(111)/TiO2/SiO2/Si(001) substrates by radio frequency magnetron sputtering. Two thin films with different (111) and (001) fiber textures were prepared. X-ray diffraction was applied to measure texture. The raw pole figure data were further processed using the MTEX quantitative texture analysis software for plotting pole figures and calculating elastic constants and Young’s modulus from the orientation distribution function (ODF) for each type of textured fiber. The calculated elastic constants were used in the theoretical studies of surface acoustics waves (SAW) propagating in two types of multilayered BST systems. Theoretical dispersion curves were plotted by the application of the ordinary differential equation (ODE) and the stiffness matrix methods (SMM). A laser acoustic waves (LAW) technique was applied to generate surface acoustic waves (SAW) propagating in the BST films, and from a recursive process, the effective Young’s modulus are determined for the two samples. These methods are used to extract and compare elastic properties of two types of BST films, and quantify the influence of texture on the direction-dependent Young’s modulus.

X-ray photoelectron spectroscopy characterization of composite TiO 2-poly(vinylidenefluoride) films synthesised for applications in pesticide photocatalytic degradation

NASA Astrophysics Data System (ADS)

Losito, I.; Amorisco, A.; Palmisano, F.; Zambonin, P. G.

2005-02-01

X-ray photoelectron spectroscopy (XPS) was adopted for the analytical characterization of composite titanium dioxide-poly(vinylidenefluoride) (TiO 2-PVDF) films developed for applications in the photocatalytic degradation of pollutants. The composites were deposited on glass substrates by casting or spin coating from TiO 2-PVDF suspensions in dimethylformamide (DMF). XPS data on the TiO 2-PVDF surface composition were used to optimize preparation conditions (composition of the TiO 2/PVDF suspension, deposition technique) in terms of titanium dioxide surface amount and film stability. The use of spin-coating deposition and the increase of TiO 2 amount in the DMF suspensions were found to improve the titanium surface content, although high TiO 2/PVDF ratios led to film instability. PVDF-TiO 2 films were also used in preliminary photocatalytic degradation tests on isoproturon, a phenylurea herbicide, under solar UV irradiation; the results were compared to direct photolysis to evaluate the catalytic efficiency of immobilized TiO 2 and the role played by the PVDF film during the degradation process.

Porous plug phase separator and superfluid film flow suppression system for the soft x-ray spectrometer onboard Hitomi

NASA Astrophysics Data System (ADS)

Ezoe, Yuichiro; DiPirro, Michael; Fujimoto, Ryuichi; Ishikawa, Kumi; Ishisaki, Yoshitaka; Kanao, Kenichi; Kimball, Mark; Mitsuda, Kazuhisa; Mitsuishi, Ikuyuki; Murakami, Masahide; Noda, Hirofumi; Ohashi, Takaya; Okamoto, Atsushi; Satoh, Yohichi; Sato, Kosuke; Shirron, Peter; Tsunematsu, Shoji; Yamaguchi, Hiroya; Yoshida, Seiji

2018-01-01

When using superfluid helium in low-gravity environments, porous plug phase separators are commonly used to vent boil-off gas while confining the bulk liquid to the tank. Invariably, there is a flow of superfluid film from the perimeter of the porous plug down the vent line. For the soft x-ray spectrometer onboard ASTRO-H (Hitomi), its approximately 30-liter helium supply has a lifetime requirement of more than 3 years. A nominal vent rate is estimated as ˜30 μg/s, equivalent to ˜0.7 mW heat load. It is, therefore, critical to suppress any film flow whose evaporation would not provide direct cooling of the remaining liquid helium. That is, the porous plug vent system must be designed to both minimize film flow and to ensure maximum extraction of latent heat from the film. The design goal for Hitomi is to reduce the film flow losses to <2 μg/s, corresponding to a loss of cooling capacity of <40 μW. The design adopts the same general design as implemented for Astro-E and E2, using a vent system composed of a porous plug, combined with an orifice, a heat exchanger, and knife-edge devices. Design, on-ground testing results, and in-orbit performance are described.

X-Ray Absorption Microspectroscopy with Electrostatic Force Microscopy and its Application to Chemical States Mapping

NASA Astrophysics Data System (ADS)

Ishii, M.; Rigopoulos, N.; Poolton, N. R. J.; Hamilton, B.

2007-02-01

A new technique named X-EFM that measures the x-ray absorption fine structure (XAFS) of nanometer objects was developed. In X-EFM, electrostatic force microscopy (EFM) is used as an x-ray absorption detector, and photoionization induced by x-ray absorption of surface electron trapping sites is detected by EFM. An EFM signal with respect to x-ray photon energy provides the XAFS spectra of the trapping sites. We adopted X-EFM to observe Si oxide thin films. An edge jump shift intrinsic to the X-EFM spectrum was found, and it was explained with a model where an electric field between the trapping site and probe deepens the energy level of the inner-shell. A scanning probe under x-rays with fixed photon energy provided the chemical state mapping on the surface.

Recent X-ray Variability of Eta Car Approaching The X-ray Eclipse

NASA Technical Reports Server (NTRS)

Corcoran, M.; Swank, J. H.; Ishibashi, K.; Gull, T.; Humphreys, R.; Damineli, A.; Walborn, N.; Hillier, D. J.; Davidson, K.; White, S. M.

2002-01-01

We discuss recent X-ray spectral variability of the supermassive star Eta Car in the interval since the last X-ray eclipse in 1998. We concentrate on the interval just prior to the next X-ray eclipse which is expected to occur in June 2003. We compare the X-ray behavior during the 2001-2003 cycle with the previous cycle (1996-1998) and note similarities and differences in the temporal X-ray behavior. We also compare a recent X-ray observation of Eta Car obtained with the Chandra high energy transmission grating in October 2002 with an earlier observation from Nov 2002, and interpret these results in terms of the proposed colliding wind binary model for the star. In addition we discuss planned observations for the upcoming X-ray eclipse.

Nanoconfinement platform for nanostructure quantification via grazing-transmission X-ray scattering

DOEpatents

Black, Charles T.; Yager, Kevin G.

2017-01-31

A nano-confinement platform that may allow improved quantification of the structural order of nanometer-scale systems. Sample-holder `chips` are designed for the GTSAXS experimental geometry. The platform involves fabricated nanostructured sample holders on and in one or more corners of a substrate support where the sample material of interest is positioned at the corner of the substrate support. In an embodiment, the substrate material making up the substrate support beneath the sample-holding area is removed. A scattering x-ray sample platform includes a substrate support arranged in a parallelepiped form, having a substantially flat base and a substantially flat top surface, the top surface being substantially parallel with the base, the parallelepiped having a plurality of corners. At least one corner of the substrate support has a sample holding area formed in the top surface of the substrate support and within a predetermined distance from the corner. The sample holding area includes a regular array of nano-wells formed in the top surface of the substrate support.

Soft x-ray submicron imaging detector based on point defects in LiF

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

Baldacchini, G.; Bollanti, S.; Bonfigli, F.

2005-11-15

The use of lithium fluoride (LiF) crystals and films as imaging detectors for EUV and soft-x-ray radiation is discussed. The EUV or soft-x-ray radiation can generate stable color centers, emitting in the visible spectral range an intense fluorescence from the exposed areas. The high dynamic response of the material to the received dose and the atomic scale of the color centers make this detector extremely interesting for imaging at a spatial resolution which can be much smaller than the light wavelength. Experimental results of contact microscopy imaging of test meshes demonstrate a resolution of the order of 400 nm. Thismore » high spatial resolution has been obtained in a wide field of view, up to several mm{sup 2}. Images obtained on different biological samples, as well as an investigation of a soft x-ray laser beam are presented. The behavior of the generated color centers density as a function of the deposited x-ray dose and the advantages of this new diagnostic technique for both coherent and noncoherent EUV sources, compared with CCDs detectors, photographic films, and photoresists are discussed.« less

An in situ grazing incidence x-ray scattering study of block copolymer thin films during solvent vapor annealing

NASA Astrophysics Data System (ADS)

Gu, Xiaodan; Gunkel, Ilja; Hexemer, Alexander; Russell, Thomas

2014-03-01

Although solvent vapor annealing (SVA) has been widely applied to block copolymer (BCP) thin films to obtain well-ordered microdomains, the mechanism of enhancing lateral order is not well understood. Here, we used real time in situ grazing-incidence small-angle x-ray scattering (in situGISAXS) to study the self-assembly of PS-b-P2VP BCP BCPs with different molecular weights thin films in THF vapor, a near neutral solvent for both blocks. Both swelling and deswelling behavior of BCP thin films were examined. The extent of swellingand the solvent removal rate not only affect the domain spacing of BCPs but also dictate the extent of lateral ordering of the BCP microdomains. Larger grains were observed at higher values of the swelling ratio (close to disordering). To preserve the maximal lateral ordering of the microdomains in the swollen state, the fastest solvent removal rate is required to freeze in the ordered microdomain structure of the swollen BCP film. We thanks support from U.S. Department of Energy BES under contract BES-DE-FG02-96ER45612 and ALS doctoral fellowship.

Large area soft x-ray collimator to facilitate x-ray optics testing

NASA Technical Reports Server (NTRS)

Espy, Samuel L.

1994-01-01

The first objective of this program is to design a nested conical foil x-ray optic which will collimate x-rays diverging from a point source. The collimator could then be employed in a small, inexpensive x-ray test stand which would be used to test various x-ray optics and detector systems. The second objective is to demonstrate the fabrication of the x-ray reflectors for this optic using lacquer-smoothing and zero-stress electroforming techniques.

A comparative study of optical and radiative characteristics of X-ray-induced luminescent defects in Ag-doped glass and LiF thin films and their applications in 2-D imaging

NASA Astrophysics Data System (ADS)

Kurobori, T.; Miyamoto, Y.; Maruyama, Y.; Yamamoto, T.; Sasaki, T.

2014-05-01

We report novel disk-type X-ray two-dimensional (2-D) imaging detectors utilising Ag-doped phosphate glass and lithium fluoride (LiF) thin films based on the radiophotoluminescence (RPL) and photoluminescence (PL) phenomena, respectively. The accumulated X-ray doses written in the form of atomic-scale Ag-related luminescent centres in Ag-doped glass and F-aggregated centres in LiF thin films were rapidly reconstructed as a dose distribution using a homemade readout system. The 2-D images reconstructed from the RPL and PL detectors are compared with that from the optically stimulated luminescence (OSL) detector. In addition, the optical and dosimetric characteristics of LiF thin films are investigated and evaluated. The possibilities of dose distributions with a high spatial resolution on the order of microns over large areas, a wide dynamic range covering 11 orders of magnitude and a non-destructive readout are successfully demonstrated by combining the Ag-doped glass with LiF thin films.

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

DOE PAGES

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

2015-03-02

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

Panoramic Dental X-Ray

MedlinePlus

... Physician Resources Professions Site Index A-Z Panoramic Dental X-ray Panoramic dental x-ray uses a very small dose of ... x-ray , is a two-dimensional (2-D) dental x-ray examination that captures the entire mouth ...

Detection of fruit-fly infestation in olives using X-ray imaging: Algorithm development and prospects

USDA-ARS?s Scientific Manuscript database

An algorithm using a Bayesian classifier was developed to automatically detect olive fruit fly infestations in x-ray images of olives. The data set consisted of 249 olives with various degrees of infestation and 161 non-infested olives. Each olive was x-rayed on film and digital images were acquired...

Design and image-quality performance of high resolution CMOS-based X-ray imaging detectors for digital mammography

NASA Astrophysics Data System (ADS)

Cha, B. K.; Kim, J. Y.; Kim, Y. J.; Yun, S.; Cho, G.; Kim, H. K.; Seo, C.-W.; Jeon, S.; Huh, Y.

2012-04-01

In digital X-ray imaging systems, X-ray imaging detectors based on scintillating screens with electronic devices such as charge-coupled devices (CCDs), thin-film transistors (TFT), complementary metal oxide semiconductor (CMOS) flat panel imagers have been introduced for general radiography, dental, mammography and non-destructive testing (NDT) applications. Recently, a large-area CMOS active-pixel sensor (APS) in combination with scintillation films has been widely used in a variety of digital X-ray imaging applications. We employed a scintillator-based CMOS APS image sensor for high-resolution mammography. In this work, both powder-type Gd2O2S:Tb and a columnar structured CsI:Tl scintillation screens with various thicknesses were fabricated and used as materials to convert X-ray into visible light. These scintillating screens were directly coupled to a CMOS flat panel imager with a 25 × 50 mm2 active area and a 48 μm pixel pitch for high spatial resolution acquisition. We used a W/Al mammographic X-ray source with a 30 kVp energy condition. The imaging characterization of the X-ray detector was measured and analyzed in terms of linearity in incident X-ray dose, modulation transfer function (MTF), noise-power spectrum (NPS) and detective quantum efficiency (DQE).

X-ray powder data for uranium and thorium minerals

USGS Publications Warehouse

Frondel, Clifford; Riska, Daphne; Frondel, Judith Weiss

1956-01-01

The U.S. Geological Survey has in preparation a comprehensive volume on the mineralogy of uranium and thorium. This work has been done as part of a continuing systematic survey of data on uranium and thorium minerals on behalf of the Division of Raw Materials, U.S. Atomic Energy Commission. Pending publication of this volume and in response to a widespread demand among workers in uranium and thorium mineralogy, the X-ray powder diffraction data for the known minerals that contain uranium or thorium as an essential constituent are presented here. The coverage is complete except for a few minerals for which there are no reliable data owing to lack of authentic specimens. With the exception of that for ianthinite, the new data either originated in the Geological Survey or in the Mineralogical Laboratory of Harvard University. Data from the literature or other sources were cross-checked against the files of standard patterns of these laboratories; the sources are indicated in the references. Data not accompanied by a reference were obtained from films in the Harvard Standard File and cross-checked as to the identity of the film with the Geological Survey's file. Minor differences can be expected in the d-spacings reported for the same specimens by different investigators because of the manner of preparation of the mount, the conditions of X-ray irradiation, and the method of photography and measurement of the film or chart. The Harvard and Geological Survey data all were obtained from films taken in 114-mm diameter cameras, using either ethyl cellulose and toluene or collodion spindle mounts and Straumanis-type film mounting. Unless otherwise indicated all patterns were taken with copper radiation (Kα 1.5418 A.) and nickel filter and data are given in Angstrom units. The d-spacings are not corrected for film shrinkage. The correction ordinarily is small and in general is less than either the variation in spacing arising from differences in experimental technique of

[Development of cloud chamber having thin-film entrance windows and proposal of practical training for beginners using X-ray equipment and unsealed radioactive material].

PubMed

Konishi, Yuki; Hayashi, Hiroaki; Takegami, Kazuki; Fukuda, Ikuma; Ueno, Junji

2014-01-01

A cloud chamber is a detector that can visualize the tracks of charged particles. Hayashi, et al. suggested a visualization experiment in which X-rays generated by diagnostic X-ray equipment were directed into a cloud chamber; however, there was a problem in that the wall of the cloud chamber scattered the incoming X-rays. In this study, we developed a new cloud chamber with entrance windows. Because these windows are made of thin film, we were able to direct the X-rays through them without contamination by scattered X-rays from the cloud chamber wall. We have newly proposed an experiment in which beta-particles emitted from radioisotopes are directed into a cloud chamber. We place shielding material in the cloud chamber and visualize the various shielding effects seen with the material positioned in different ways. During the experiment, electrons scattered in the air were measured quantitatively using GM counters. We explained the physical phenomena in the cloud chamber using Monte Carlo simulation code EGS5. Because electrons follow a tortuous path in air, the shielding material must be placed appropriately to be able to effectively block their emissions. Visualization of the tracks of charged particles in this experiment proved effective for instructing not only trainee radiological technologists but also different types of healthcare professionals.

Study of surface cleaning methods and pyrolysis temperatures on nanostructured carbon films using x-ray photoelectron spectroscopy

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

Kerber, Pranita; Porter, Lisa M.; McCullough, Lynne A.

2012-11-15

Nanostructured carbon (ns-C) films fabricated by stabilization and pyrolysis of diblock copolymers are of interest for a variety of electrical/electronic applications due to their chemical inertness, high-temperature insensitivity, very high surface area, and tunable electrical resistivity over a wide range [Kulkarni et al., Synth. Met. 159, 177 (2009)]. Because of their high porosity and associated high specific surface area, controlled surface cleaning studies are important for fabricating electronic devices from these films. In this study, quantification of surface composition and surface cleaning studies on ns-C films synthesized by carbonization of diblock copolymers of polyacrylonitrile-b-poly(n-butyl acrylate) at two different temperatures weremore » carried out. X-ray photoelectron spectroscopy was used for elemental analysis and to determine the efficacy of various surface cleaning methods for ns-C films and to examine the polymer residues in the films. The in-situ surface cleaning methods included HF vapor treatment, vacuum annealing, and exposure to UV-ozone. Quantitative analysis of high-resolution XPS scans showed 11 at. % nitrogen was present in the films pyrolyzed at 600 Degree-Sign C, suggesting incomplete denitrogenation of the copolymer films. The nitrogen atomic concentration decreased significantly for films pyrolyzed at 900 Degree-Sign C confirming extensive denitrogenation at that temperature. Furthermore, quantitative analysis of nitrogen subpeaks indicated higher loss of nitrogen atoms residing at the edge of graphitic clusters relative to that of nitrogen atoms within the graphitic clusters, suggesting higher graphitization with increasing pyrolysis temperature. Of the surface cleaning methods investigated, in-situ annealing of the films at 300 Degree-Sign C for 40 min was found to be the most efficacious in removing adventitious carbon and oxygen impurities from the surface.« less

X-ray Spectral Formation In High-mass X-ray Binaries: The Case Of Vela X-1

NASA Astrophysics Data System (ADS)

Akiyama, Shizuka; Mauche, C. W.; Liedahl, D. A.; Plewa, T.

2007-05-01

We are working to develop improved models of radiatively-driven mass flows in the presence of an X-ray source -- such as in X-ray binaries, cataclysmic variables, and active galactic nuclei -- in order to infer the physical properties that determine the X-ray spectra of such systems. The models integrate a three-dimensional time-dependent hydrodynamics capability (FLASH); a comprehensive and uniform set of atomic data, improved calculations of the line force multiplier that account for X-ray photoionization and non-LTE population kinetics, and X-ray emission-line models appropriate to X-ray photoionized plasmas (HULLAC); and a Monte Carlo radiation transport code that simulates Compton scattering and recombination cascades following photoionization. As a test bed, we have simulated a high-mass X-ray binary with parameters appropriate to Vela X-1. While the orbital and stellar parameters of this system are well constrained, the physics of X-ray spectral formation is less well understood because the canonical analytical wind velocity profile of OB stars does not account for the dynamical and radiative feedback effects due to the rotation of the system and to the irradiation of the stellar wind by X-rays from the neutron star. We discuss the dynamical wind structure of Vela X-1 as determined by the FLASH simulation, where in the binary the X-ray emission features originate, and how the spatial and spectral properties of the X-ray emission features are modified by Compton scattering, photoabsorption, and fluorescent emission. This work was performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

Characterization of thin films of the solid electrolyte Li(x)Mg(1-2x)Al(2+x)O4 (x = 0, 0.05, 0.15, 0.25).

PubMed

Put, Brecht; Vereecken, Philippe M; Mees, Maarten J; Rosciano, Fabio; Radu, Iuliana P; Stesmans, Andre

2015-11-21

RF-sputtered thin films of spinel Li(x)Mg(1-2x)Al(2+x)O4 were investigated for use as solid electrolyte. The usage of this material can enable the fabrication of a lattice matched battery stack, which is predicted to lead to superior battery performance. Spinel Li(x)Mg(1-2x)Al(2+x)O4 thin films, with stoichiometry (x) ranging between 0 and 0.25, were formed after a crystallization anneal as shown by X-ray diffraction and transmission electron microscopy. The stoichiometry of the films was evaluated by elastic recoil detection and Rutherford backscattering and found to be slightly aluminum rich. The excellent electronic insulation properties were confirmed by both current-voltage measurements as well as by copper plating tests. The electrochemical stability window of the material was probed using cyclic voltammetry. Lithium plating and stripping was observed together with the formation of a Li-Pt alloy, indicating that Li-ions passed through the film. This observation contradicted with impedance measurements at open circuit potential, which showed no apparent Li-ion conductivity of the film. Impedance spectroscopy as a function of potential showed the occurrence of Li-ion intercalation into the Li(x)Mg(1-2x)Al(2+x)O4 layers. When incorporating Li-ions in the material the ionic conductivity can be increased by 3 orders of magnitude. Therefore it is anticipated that the response of Li(x)Mg(1-2x)Al(2+x)O4 is more adequate for a buffer layer than as the solid electrolyte.

Engineering solar cells based on correlative X-ray microscopy

DOE PAGES

Stuckelberger, Michael; West, Bradley; Nietzold, Tara; ...

2017-05-01

In situ and operando measurement techniques combined with nanoscale resolution have proven invaluable in multiple fields of study. We argue that evaluating device performance as well as material behavior by correlative X-ray microscopy with <100 nm resolution can radically change the approach for optimizing absorbers, interfaces and full devices in solar cell research. Here, we thoroughly discuss the measurement technique of X-ray beam induced current and point out fundamental differences between measurements of wafer-based silicon and thin-film solar cells. Based on reports of the last years, we showcase the potential that X-ray microscopy measurements have in combination with in situmore » and operando approaches throughout the solar cell lifecycle: from the growth of individual layers to the performance under operating conditions and degradation mechanisms. Enabled by new developments in synchrotron beamlines, the combination of high spatial resolution with high brilliance and a safe working distance allows for the insertion of measurement equipment that can pave the way for a new class of experiments. When applied to photovoltaics research, we highlight today’s opportunities and challenges in the field of nanoscale X-ray microscopy, and give an outlook on future developments.« less

X-ray and gamma ray astronomy detectors

NASA Technical Reports Server (NTRS)

Decher, Rudolf; Ramsey, Brian D.; Austin, Robert

1994-01-01

X-ray and gamma ray astronomy was made possible by the advent of space flight. Discovery and early observations of celestial x-rays and gamma rays, dating back almost 40 years, were first done with high altitude rockets, followed by Earth-orbiting satellites> once it became possible to carry detectors above the Earth's atmosphere, a new view of the universe in the high-energy part of the electromagnetic spectrum evolved. Many of the detector concepts used for x-ray and gamma ray astronomy were derived from radiation measuring instruments used in atomic physics, nuclear physics, and other fields. However, these instruments, when used in x-ray and gamma ray astronomy, have to meet unique and demanding requirements related to their operation in space and the need to detect and measure extremely weak radiation fluxes from celestial x-ray and gamma ray sources. Their design for x-ray and gamma ray astronomy has, therefore, become a rather specialized and rapidly advancing field in which improved sensitivity, higher energy and spatial resolution, wider spectral coverage, and enhanced imaging capabilities are all sought. This text is intended as an introduction to x-ray and gamma ray astronomy instruments. It provides an overview of detector design and technology and is aimed at scientists, engineers, and technical personnel and managers associated with this field. The discussion is limited to basic principles and design concepts and provides examples of applications in past, present, and future space flight missions.

Nanosecond time resolved x-ray diagnostics of relativistic electron beam initiated events

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

Kuswa, Glenn W.; Chang, James

The dynamic behavior of a test sample during aid shortly after it has teen irradiated by an intense relativistic electron beam (REB) is of great interest to the study of team energy deposition. Since the sample densities are far beyond the cutoff in the optical region, flash x-radiography techniques have been developed to diagnose the evolution of the samples. The conventional approach of analyzing the dynamic behavior of solid densities utilizes one or more short x-ray bursts to record images on photographic emulsion. This technique is not useful in the presence of the intense x-rays from the REB interacting withmore » the sample. We report two techniques for isolating the film package from the REB x-ray pulse.« less

X-ray imaging crystal spectrometer for extended X-ray sources

DOEpatents

Bitter, Manfred L.; Fraenkel, Ben; Gorman, James L.; Hill, Kenneth W.; Roquemore, A. Lane; Stodiek, Wolfgang; von Goeler, Schweickhard E.

2001-01-01

Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokomak fusion experiment to provide spatially and temporally resolved data on plasma parameters using the imaging properties for Bragg angles near 45. For a Bragg angle of 45.degree., the spherical crystal focuses a bundle of near parallel X-rays (the cross section of which is determined by the cross section of the crystal) from the plasma to a point on a detector, with parallel rays inclined to the main plain of diffraction focused to different points on the detector. Thus, it is possible to radially image the plasma X-ray emission in different wavelengths simultaneously with a single crystal.

Measurement of breast-tissue x-ray attenuation by spectral mammography: solid lesions

NASA Astrophysics Data System (ADS)

Fredenberg, Erik; Kilburn-Toppin, Fleur; Willsher, Paula; Moa, Elin; Danielsson, Mats; Dance, David R.; Young, Kenneth C.; Wallis, Matthew G.

2016-04-01

Knowledge of x-ray attenuation is essential for developing and evaluating x-ray imaging technologies. For instance, techniques to distinguish between cysts and solid tumours at mammography screening would be highly desirable to reduce recalls, but the development requires knowledge of the x-ray attenuation for cysts and tumours. We have previously measured the attenuation of cyst fluid using photon-counting spectral mammography. Data on x-ray attenuation for solid breast lesions are available in the literature, but cover a relatively wide range, likely caused by natural spread between samples, random measurement errors, and different experimental conditions. In this study, we have adapted a previously developed spectral method to measure the linear attenuation of solid breast lesions. A total of 56 malignant and 5 benign lesions were included in the study. The samples were placed in a holder that allowed for thickness measurement. Spectral (energy-resolved) images of the samples were acquired and the image signal was mapped to equivalent thicknesses of two known reference materials, which can be used to derive the x-ray attenuation as a function of energy. The spread in equivalent material thicknesses was relatively large between samples, which is likely to be caused mainly by natural variation and only to a minor extent by random measurement errors and sample inhomogeneity. No significant difference in attenuation was found between benign and malignant solid lesions. The separation between cyst-fluid and tumour attenuation was, however, significant, which suggests it may be possible to distinguish cystic from solid breast lesions, and the results lay the groundwork for a clinical trial. In addition, the study adds a relatively large sample set to the published data and may contribute to a reduction in the overall uncertainty in the literature.

Local structure study of (In{sub 0.95−x}Fe{sub x}Cu{sub 0.05}){sub 2}O{sub 3} thin films using x-ray absorption spectroscopy

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

Ren, Yuan; Xing, Yaya; Ma, Guanxiong

2015-07-15

The (In{sub 0.95−x}Fe{sub x}Cu{sub 0.05}){sub 2}O{sub 3} (x = 0.06, 0.08, 0.15, and 0.20) films prepared by RF-magnetron sputtering were investigated by the combination of x-ray absorption spectroscopy (XAS) at Fe, Cu, and O K-edge. Although the Fe and O K-edge XAS spectra show that the Fe atoms substitute for the In sites of In{sub 2}O{sub 3} lattice for all the films, the Cu K-edge XAS spectra reveal that the codoped Cu atoms are separated to form the Cu metal clusters. After being annealed in air, the Fe atoms are still substitutionally incorporated into the In{sub 2}O{sub 3} lattice, while the Cumore » atoms form the CuO secondary phases. With the increase of Fe concentration, the bond length R{sub Fe-O} shortens and the Debye–Waller factor σ{sup 2}{sub Fe-O} increases in the first coordination shell of Fe, which are attributed to the relaxation of oxygen environment around the substitutional Fe ions. The forming of Cu relating secondary phases in the films is due to high ionization energy of Cu atoms, leading that the Cu atoms are energetically much harder to be oxidized to substitute for the In sites of In{sub 2}O{sub 3} lattice than Fe atoms. These results provide new experimental guidance in the preparation of the codoped In{sub 2}O{sub 3} based dilute magnetic oxides.« less

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.

X-ray lithography source

DOEpatents

Piestrup, Melvin A.; Boyers, David G.; Pincus, Cary

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.

Bone cartilage imaging with x-ray interferometry using a practical x-ray tube

NASA Astrophysics Data System (ADS)

Kido, Kazuhiro; Makifuchi, Chiho; Kiyohara, Junko; Itou, Tsukasa; Honda, Chika; Momose, Atsushi

2010-04-01

The purpose of this study was to design an X-ray Talbot-Lau interferometer for the imaging of bone cartilage using a practical X-ray tube and to develop that imaging system for clinical use. Wave-optics simulation was performed to design the interferometer with a practical X-ray tube, a source grating, two X-ray gratings, and an X-ray detector. An imaging system was created based on the results of the simulation. The specifications were as follows: the focal spot size was 0.3 mm of an X-ray tube with a tungsten anode (Toshiba, Tokyo, Japan). The tube voltage was set at 40 kVp with an additive aluminum filter, and the mean energy was 31 keV. The pixel size of the X-ray detector, a Condor 486 (Fairchild Imaging, California, USA), was 15 μm. The second grating was a Ronchi-type grating whose pitch was 5.3 μm. Imaging performance of the system was examined with X-ray doses of 0.5, 3 and 9 mGy so that the bone cartilage of a chicken wing was clearly depicted with X-ray doses of 3 and 9 mGy. This was consistent with the simulation's predictions. The results suggest that X-ray Talbot-Lau interferometry would be a promising tool in detecting soft tissues in the human body such as bone cartilage for the X-ray image diagnosis of rheumatoid arthritis. Further optimization of the system will follow to reduce the X-ray dose for clinical use.

Bandpass x-ray diode and x-ray multiplier detector

DOEpatents

Wang, C.L.

1982-09-27

An absorption-edge of an x-ray absorption filter and a quantum jump of a photocathode determine the bandpass characteristics of an x-ray diode detector. An anode, which collects the photoelectrons emitted by the photocathode, has enhanced amplification provided by photoelectron-multiplying means which include dynodes or a microchannel-plate electron-multiplier. Suppression of undesired high frequency response for a bandpass x-ray diode is provided by subtracting a signal representative of energies above the passband from a signal representative of the overall response of the bandpass diode.

X-ray astronomical spectroscopy

NASA Technical Reports Server (NTRS)

Holt, Stephen S.

1987-01-01

The contributions of the Goddard group to the history of X-ray astronomy are numerous and varied. One role that the group has continued to play involves the pursuit of techniques for the measurement and interpretation of the X-ray spectra of cosmic sources. The latest development is the selection of the X-ray microcalorimeter for the Advanced X-ray Astrophysics Facility (AXAF) study payload. This technology is likely to revolutionize the study of cosmic X-ray spectra.

Depth profiling of marker layers using x-ray waveguide structures

NASA Astrophysics Data System (ADS)

Gupta, Ajay; Rajput, Parasmani; Saraiya, Amit; Reddy, V. R.; Gupta, Mukul; Bernstorff, Sigrid; Amenitsch, H.

2005-08-01

It is demonstrated that x-ray waveguide structures can be used for depth profiling of a marker layer inside the guiding layer with an accuracy of better than 0.2 nm. A combination of x-ray fluorescence and x-ray reflectivity measurements can provide detailed information about the structure of the guiding layer. The position and thickness of the marker layer affect different aspects of the angle-dependent x-ray fluorescence pattern, thus making it possible to determine the structure of the marker layer in an unambiguous manner. As an example, effects of swift heavy ion irradiation on a Si/M/Si trilayer ( M=Fe , W), forming the cavity of the waveguide structure, have been studied. It is found that in accordance with the prediction of thermal spike model, Fe is much more sensitive to swift heavy ion induced modifications as compared to W, even in thin film form. However, a clear evidence of movement of the Fe marker layer towards the surface is observed after irradiation, which cannot be understood in terms of the thermal spike model alone.

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

NASA Technical Reports Server (NTRS)

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

X-Ray

MedlinePlus

... of gray. For some types of X-ray tests, a contrast medium — such as iodine or barium — is introduced into your body to provide greater detail on the images. Why it's done X-ray technology is used to examine many parts of the ...

Cross-calibration of Fuji TR image plate and RAR 2492 x-ray film to determine the response of a DITABIS Super Micron image plate scanner

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

Dunham, G., E-mail: gsdunha@sandia.gov; Harding, E. C.; Loisel, G. P.

Fuji TR image plate is frequently used as a replacement detector medium for x-ray imaging and spectroscopy diagnostics at NIF, Omega, and Z facilities. However, the familiar Fuji BAS line of image plate scanners is no longer supported by the industry, and so a replacement scanning system is needed. While the General Electric Typhoon line of scanners could replace the Fuji systems, the shift away from photo stimulated luminescence units to 16-bit grayscale Tag Image File Format (TIFF) leaves a discontinuity when comparing data collected from both systems. For the purposes of quantitative spectroscopy, a known unit of intensity appliedmore » to the grayscale values of the TIFF is needed. The DITABIS Super Micron image plate scanning system was tested and shown to potentially rival the resolution and dynamic range of Kodak RAR 2492 x-ray film. However, the absolute sensitivity of the scanner is unknown. In this work, a methodology to cross calibrate Fuji TR image plate and the absolutely calibrated Kodak RAR 2492 x-ray film is presented. Details of the experimental configurations used are included. An energy dependent scale factor to convert Fuji TR IP scanned on a DITABIS Super Micron scanner from 16-bit grayscale TIFF to intensity units (i.e., photons per square micron) is discussed.« less

X-ray luminescence computed tomography using a focused x-ray beam.

PubMed