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Interferometry
Kinds of Interferometry Selected AbstractsRESIDUAL STRESS MEASUREMENT USING THE HOLE DRILLING METHOD AND LASER SPECKLE INTERFEROMETRYEXPERIMENTAL TECHNIQUES, Issue 4 2003E. Ponslet First page of article [source] REAL-TIME DIGITAL SPECKLE INTERFEROMETRY TO MEASURE CRACK LENGTHEXPERIMENTAL TECHNIQUES, Issue 1 2002G.L. Cloud No abstract is available for this article. [source] CORRELATION SPECKLE INTERFEROMETRY FOR DISPLACEMENT MEASUREMENT IN CRT-PANELSEXPERIMENTAL TECHNIQUES, Issue 4 2001M.J. Huang First page of article [source] MEASUREMENT OF THERMAL EXPANSION COEFFICIENT OF FLEXIBLE SUBSTRATE BY MOIRÉ INTERFEROMETRYEXPERIMENTAL TECHNIQUES, Issue 3 2001B. Han First page of article [source] Surface deformation induced by present-day ice melting in SvalbardGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2009H. P. Kierulf SUMMARY The vertical movement of the Earth's surface is the result of a number of internal processes in the solid Earth, tidal forces and mass redistribution in the atmosphere, oceans, terrestrial hydrosphere and cryosphere. Close to ice sheets and glaciers, the changes in the ice loads can induce large vertical motions at intraseasonal to secular timescales. The Global Positioning System (GPS) and Very Long Baseline Interferometry (VLBI) antennas in Ny-Ålesund, Svalbard that started observations in 1991 and 1995, respectively, observe vertical uplift rates on the order of 8 ± 2 mm yr,1, which are considerably larger than those predicted by postglacial rebound (PGR) models (order 2 mm yr,1). The observations also indicate increased uplift rates starting some time in 2000. A local GPS campaign network that has been reoccupied annually since 1998, reveals a tilting away from the neighbouring glaciers. The Svalbard glaciers have been undergoing melting and retreat during the last century, with increased melting since about 2000. We compared the observed vertical motion to the motion predicted by loading models using a detailed ice model with annual time resolution as forcing. The model predictions correlate well with the observations both with respect to the interannual variations and the spatial pattern of long-term trends. The regression coefficients for predicted and observed interannual variations in height is 1.08 ± 0.38, whereas the regression coefficient for the predicted and observed spatial pattern turns out to be 1.26 ± 0.42. Estimates of the predicted secular trend in height due to PGR and present-day melting are on the order of 4.8 ± 0.3 mm yr,1 and thus smaller than the observed secular trend in height. This discrepancy between predictions and observations is likely caused by the sum of errors in the secular rates determined from observations (due to technique-dependent large-scale offsets) and incomplete or erroneous models (unaccounted tectonic vertical motion, errors in the ice load history, scale errors in the viscoelastic PGR models and the elastic models for present-day melting). [source] Design Strategy of Minipig Molars Using Electronic Speckle Pattern Interferometry: Comparison of Deformation under Load between the Tooth-Mandible Complex and the Isolated Tooth,ADVANCED MATERIALS, Issue 4 2009Netta Lev-Tov Chattah Using electronic speckle pattern interferometry minipig molars were tested under load inside the bone socket and when embedded in a stiff polymer. It is demonstrated that the molar bends in the direction of the load in both configurations even at low loads. This shows that the intrinsic reaction of the tooth crown to load is complemented by the structures supporting the tooth. [source] SPIDER: A decade of measuring ultrashort pulsesLASER PHYSICS LETTERS, Issue 4 2008M.E. Anderson Abstract It was ten years ago in Rochester, New York that the first SPIDER was built. This simple acronym belies the subtleties of its inner workings; Spectral Phase Interferometry for Direct Electric-field Reconstruction (the "f" in field conveniently missed the cut) is a device that measures ultrashort pulses, utilizing spectral shearing interferometry and directly recovering the spectral phase. The very first SPIDER apparatus occupied nearly half an optical table, used a scanning monochromator, and had no computerized inversion routine. In the intervening decade, SPIDER has grown up. It has found a strong foothold in ultrafast laboratories throughout the world. Multiple groups have found useful new applications with this vital measurement tool, while others have contributed to the improvement of SPIDER itself, reaching to ever shorter pulses, new wavelength regimes, and making devices more sensitive, robust, smaller and faster. It also adapts to a field of research that changes rapidly. It was first designed to track and quantify the remaining spectral phase in a pulse to perfect its compression. In ten years, with the advent of pulse shapers, the real benefits of field diagnostics are becoming apparent. We have shifted away from the race towards the shortest IR pulse to a wide use of complex shaped pulses in almost every spectral range from far IR to XUV. But the quest of the shortest pulse is not over and new compression techniques utilize really broad spectra that are highly structured. All these applications provide new challenges for characterization techniques. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Bulk motion of ultrarelativistic conical blazar jetsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2006Gopal-Krishna ABSTRACT Allowing for the conical shape of ultrarelativistic blazar jets with opening angles of a few degrees on parsec-scales, we show that their bulk Lorentz factors and viewing angles can be much larger than the values usually inferred by combining their flux-variability and proper-motion measurements. This is in accord with our earlier finding that such ultrarelativistic (Lorentz factor, , > 30) conical jets can reconcile the relatively slow apparent motions of Very Long Baseline Interferometry (VLBI) knots in TeV blazars with the extremely fast flows implied by their rapid ,-ray variability. This jet geometry also implies that de-projected jet opening angles will typically be significantly underestimated from VLBI measurements. In addition, de-projected jet lengths will be considerably overestimated if high Lorentz factors and significant opening angles are not taken into account. [source] Raman interferometry: probing nanostructures by acoustic phononsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2004F. Poinsotte Abstract We report on a non-destructive and reliable technique to characterize nanostructures based on low frequency Raman scattering interferences. Raman Interferometry uses THz acoustic phonons to investigate semiconductors nanostructures. By combining experiments with spectra modelling and Fourier analysis, quantitative information on the electronic state localisation and on structural parameters can be obtained. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Damage Detection by Wave Propagation Observation with Laser SpeckleInterferometryPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2005Alexander Schmidt For quality insurance and fault detection, one and three dimensional ESPI (Electronic Speckle Pattern Interferometry) technique is applied to various structures. These experiments are an extension of previous experiments with Holographic Interferometry [4], a related measurement technique. ESPI is a non contact, high resolution Laser measurement technique. It facilitates transient full field vibration measurements that deliver absolute deflections, either one dimensional out-of-plane or three dimensional in and out-of-plane. Experiments have been performed with a full scale concrete embedded track segment. Different known artificial defects represent various flaws and voids due to the fabrication process and operation. Wave propagation due to impact is observed and allows for damage detection. ESPI measurements are in good accordance with expectations. An in-situ measurement setup for quality management of concrete embedded railway tracks has been built. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Interferometric Insights into the Cycle of MatterASTRONOMISCHE NACHRICHTEN, Issue S2 2003Katharina Schreyer C01 A Multiplicity Survey of the , Oph Molecular Cloud , Preliminary Results C02 Bispectrum Speckle Interferometry of Young Jet- and Outflow-sources [source] Electronic Speckle Pattern Interferometry: A Tool for Determining Diffusion and Partition Coefficients for Proteins in GelsBIOTECHNOLOGY PROGRESS, Issue 6 2002David Karlsson The aim of this study was to demonstrate electronic speckle pattern interferometry (ESPI) as a powerful tool in determining diffusion coefficients and partition coefficients for proteins in gels. ESPI employs a CCD camera instead of a holographic plate as in conventional holographic interferometry. This gives the advantage of being able to choose the reference state freely. If a hologram at the reference state is taken and compared to a hologram during the diffusion process, an interferometric picture can be generated that describes the refraction index gradients and thus the concentration gradients in the gel as well as in the liquid. MATLAB is then used to fit Fick's law to the experimental data to obtain the diffusion coefficients in gel and liquid. The partition coefficient is obtained from the same experiment from the flux condition at the interface between gel and liquid. This makes the comparison between the different diffusants more reliable than when the measurements are performed in separate experiments. The diffusion and partitioning coefficients of lysozyme, BSA, and IgG in 4% agarose gel at pH 5.6 and in 0.1 M NaCl have been determined. In the gel the diffusion coefficients were 11.2 ± 1.6, 4.8 ± 0.6, and 3.0 ± 0.3 m2/s for lysozyme, BSA, and IgG, respectively. The partition coefficients were determined to be 0.65 ± 0.04, 0.44 ± 0.06, and 0.51 ± 0.04 for lysozyme, BSA, and IgG, respectively. The current study shows that ESPI is easy to use and gives diffusion coefficients and partition coefficients for proteins with sufficient accuracy from the same experiment. [source] Generation of Nanopores Down to 10 nm for Use in Deep-Nulling InterferometryCHEMPHYSCHEM, Issue 2 2008Axel Wehling Dr. Abstract Scanning electron microscope images show that it is easy to generate nanopores on polycarbonate membranes with well-defined pore diameters by ion-track perforation and subsequent magnetron sputtering with metal. The size reduction of the nanopores during sputtering with gold is a linear function of time. Images of different angles and from the bottom side of the membrane show that the channels are the smallest very close to the surface of the metal layer, have a conelike shape, and reach about half as much into the polymer membranes as the metal-layer thickness. This topographical pore shape is ideal for use as optically coherent near-field sources in deep-nulling microscopy. We present the first results of significantly improved nulling stabilization in the presence (<2 nm optical pathway difference) and the absence (<0.6 nm optical pathway difference) of the nanoapertures in the focal region of a deep-nulling microscope. [source] Free fatty acids exert a greater effect on ocular and skin blood flow than triglycerides in healthy subjectsEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 8 2004M. Bayerle-Eder Abstract Background, Free fatty acids (FFAs) and triglycerides (TGs) can cause vascular dysfunction and arteriosclerosis. Acute elevation of plasma FFA and TG concentration strongly increase ocular and skin blood flow. This study was designed to discriminate whether FFA or TG independently induce hyperperfusion by measuring regional and systemic haemodynamics. Methods, In a balanced, randomized, placebo-controlled, double-blind, three-way, crossover study nine healthy subjects received either Intralipid® (Pharmacia and Upjohn, Vienna, Austria) with heparin, Intralipid® alone or placebo control. Pulsatile choroidal blood flow was measured with laser interferometry, retinal blood flow and retinal red blood cell velocity with laser Doppler velocimetry, and skin blood flow with laser Doppler flowmetry during an euglycaemic insulin clamp. Results, A sevenfold increase of FFA during Intralipid®/heparin infusion was paralleled by enhanced choriodal, retinal, and skin blood flow by 17 ± 4%, 26 ± 5% (P < 0·001), and 47 ± 19% (P = 0·03) from baseline, respectively. In contrast, a mere threefold increase of FFA by infusion of Intralipid® alone did not affect outcome parameters, despite the presence of plasma TG levels of 250,700 mg dL,1; similar to those obtained during combined Intralipid®/heparin infusion. Systemic haemodynamics were not affected by drug infusion. Conclusions, Present findings demonstrate a concentration-dependent increase in ocular and skin blood flow by FFA independently of elevated TG plasma concentrations. As vasodilation of resistance vessels occur rapidly, FFA may play a role in the development of continued regional hyperperfusion and deteriorate microvascular function. [source] Advanced resonant ultrasound spectroscopy for measuring anisotropic elastic constants of thin filmsFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 8 2005H. OGI ABSTRACT This paper presents an advanced resonant ultrasound spectroscopy (RUS) method to determine the elastic constants Cij of thin films. Polycrystalline thin films often exhibit elastic anisotropy between the film growth direction and the in-plane direction, and they macroscopically show five independent elastic constants. Because all of the Cij of a deposited thin film affect the mechanical resonance frequencies of the film/substrate layer specimen, measuring resonance frequencies enables one to determine the Cij of the film with known density, dimensions and the Cij of the substrate. Resonance frequencies have to be measured accurately because of low sensitivity of the Cij of films to them. We achieved this by a piezoelectric tripod. Mode identification has to be made unambiguously. We made this measuring displacement,amplitude distributions on the resonated specimen surface by laser Doppler interferometry. We applied our technique to copper thin film and diamond thin film. They show elastic anisotropy and the Cij smaller than bulk values of Cij. Micromechanics calculations indicate the presence of incohesive bonded regions. [source] Optimizing atom interferometry on atom chipsFORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 11-12 2009U. Hohenester Abstract We theoretically investigate the performance of atom interferometers based on ultracold atoms and atom chips. Within the framework of the Gross-Pitaevskii equation, we simulate the splitting and trapping of a condensate. Within the two-mode model and the multi-configurational Hartree method for Bosons, we investigate number squeezing and its impact on the interferometer performance. We show that optimized control strategies allow for efficient condensate trapping and number squeezing on short time scales. [source] Multiphoton entanglement and interferometryFORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 4-5 2003M. Bourennane Multiphoton entanglement is the basis of many quantum communication schemes, quantum cryptographic protocols, and fundamental tests of quantum theory. Spontaneous parametric down-conversion is the most effective source for polarization entangled photon pairs. Here we show, that a class of entangled 4-photon states can be directly created by parametric down-conversion. These states exhibit perfect quantum correlations and a high robustness of entanglement against photon loss. Therefore these states are well suited for new types of quantum communication. [source] Quantum interferometry with intense optical pulsesFORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 4-5 2003G. Leuchs For intense optical pulses the optical Kerr interaction in matter such as an optical fiber is large enough to generate quantum states of light with significant non-classical properties. On this basis pairs of entangled light pulses have been generated. This entanglement can be used for novel schemes in high precision interferometry and for quantum communication protocols such as quantum dense coding. [source] Required source distribution for interferometry of waves and diffusive fieldsGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2009Yuanzhong Fan SUMMARY The Green's function that describes wave propagation between two receivers can be reconstructed by cross-correlation provided that the receivers are surrounded by sources on a closed surface. This technique is referred to as ,interferometry' in exploration seismology. The same technique for Green's function extraction can be applied to the solution of the diffusion equation if there are sources throughout in the volume. In practice, we have only a finite number of active sources. The issues of the required source distribution is investigated, as is the feasibility of reconstructing the Green's function of the diffusion equation using a limited number of sources within a finite volume. We study these questions for homogeneous and heterogeneous media for wave propagation and homogeneous media for diffusion using numerical simulations. These simulations show that for the used model, the angular distribution of sources is critical in wave problems in homogeneous media. In heterogeneous media, the position and size of the heterogeneous area with respect to the sources determine the required source distribution. For diffusion, the sensitivity to the sources decays from the midpoint between the two receivers. The required width of the source distribution decreases with frequency, with the result that the required source distribution for early- and late-time reconstruction is different. The derived source distribution criterion for diffusion suggests that the cross-correlation-based interferometry is difficult to apply in field condition. [source] Monitoring in situ stress changes in a mining environment with coda wave interferometryGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2006Alexandre Grêt SUMMARY Coda waves are highly sensitive to changes in the subsurface; we use this sensitivity to monitor small stress changes in an underground mine. We apply coda wave interferometry to seismic data excited by a hammer source, collected at an experimental hard rock mine in Idaho Springs, CO. We carried out a controlled stress-change experiment in a mine pillar and we show how coda wave interferometry can be used to monitor the in situ stress change with modest hardware requirements. [source] Application of SAR interferometry to a large thrust deformation: the 1999 Mw= 7.6 Chichi earthquake in central TaiwanGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2004C. P. Chang SUMMARY Application of the interferometric method to four ERS2-SAR images acquired before and after the 1999 Chichi earthquake has allowed determination of the coseismic surface displacement in the footwall area of the Chelungpu fault. The interferometric results revealed a relative shortening in the round trip distance between the radar antenna and the ground of the footwall side of Chelungpu fault, during the earthquake. This shortening progressively increased from the west to the east and reaches the maximum amount of approximately 26 cm near the central segment of the Chelungpu fault. Our interferometric results have been precisely examined using a dense GPS network in the investigated area. We mapped the GPS coseismic measurements into the radar line of sight and implemented a forward simulation of SAR interferogram from this synthesized result to control our unwrapping performance. In this study, these two observations are compared with a 3-D dislocation model of the fault. Finally, a deformation analysis based on our interferometric result has indicated that a segment with irregular deformation behaviour can be distinguished in the footwall area of the Chelungpu fault. This segment may result from either the influence of inherited basement faults or the presence of a structural terrace that provide local opportunities for superficial deformation. [source] Geodetic imaging: reservoir monitoring using satellite interferometryGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2002D. W. Vasco Summary Fluid fluxes within subsurface reservoirs give rise to surface displacements, particularly over periods of a year or more. Observations of such deformation provide a powerful tool for mapping fluid migration within the Earth, providing new insights into reservoir dynamics. In this paper we use Interferometric Synthetic Aperture Radar (InSAR) range changes to infer subsurface fluid volume strain at the Coso geothermal field. Furthermore, we conduct a complete model assessment, using an iterative approach to compute model parameter resolution and covariance matrices. The method is a generalization of a Lanczos-based technique which allows us to include fairly general regularization, such as roughness penalties. We find that we can resolve quite detailed lateral variations in volume strain both within the reservoir depth range (0.4,2.5 km) and below the geothermal production zone (2.5,5.0 km). The fractional volume change in all three layers of the model exceeds the estimated model parameter uncertainty by a factor of two or more. In the reservoir depth interval (0.4,2.5 km), the predominant volume change is associated with northerly and westerly oriented faults and their intersections. However, below the geothermal production zone proper [the depth range 2.5,5.0 km], there is the suggestion that both north- and northeast-trending faults may act as conduits for fluid flow. [source] Seismic interferometry, intrinsic losses and Q -estimation,GEOPHYSICAL PROSPECTING, Issue 3 2010Deyan Draganov ABSTRACT Seismic interferometry is the process of generating new seismic traces from the cross-correlation, convolution or deconvolution of existing traces. One of the starting assumptions for deriving the representations for seismic interferometry by cross-correlation is that there is no intrinsic loss in the medium where the recordings are performed. In practice, this condition is not always met. Here, we investigate the effect of intrinsic losses in the medium on the results retrieved from seismic interferometry by cross-correlation. First, we show results from a laboratory experiment in a homogeneous sand chamber with strong losses. Then, using numerical modelling results, we show that in the case of a lossy medium ghost reflections will appear in the cross-correlation result when internal multiple scattering occurs. We also show that if a loss compensation is applied to the traces to be correlated, these ghosts in the retrieved result can be weakened, can disappear, or can reverse their polarity. This compensation process can be used to estimate the quality factor in the medium. [source] Synthesis of a seismic virtual reflector,GEOPHYSICAL PROSPECTING, Issue 3 2010Flavio Poletto ABSTRACT We describe a method to process the seismic data generated by a plurality of sources and registered by an appropriate distribution of receivers, which provides new seismic signals as if in the position of the receivers (or sources) there was an ideal reflector, even if this reflector is not present there. The data provided by this method represent the signals of a virtual reflector. The proposed algorithm performs the convolution and the subsequent sum of the real traces without needing subsurface model information. The approach can be used in combination with seismic interferometry to separate wavefields and process the reflection events. The application is described with synthetic examples, including stationary phase analysis and with real data in which the virtual reflector signal can be appreciated. [source] Consistency of the spatial autocorrelation method with seismic interferometry and its consequenceGEOPHYSICAL PROSPECTING, Issue 3 2008Toshiaki Yokoi ABSTRACT We have cross-checked the conventional theory of the spatial autocorrelation method and the consequence of seismic interferometry: the retrieval of the elastodynamic Green's function. Their mutual consistency is almost complete. The basic formulas of the conventional spatial autocorrelation theory can be derived by an alternative approach based on the retrieval of the elastodynamic Green's function. The only discrepancy is found with the average of the complex coherence function over azimuth in a wavefield dependent on azimuth. It is hypothesized, in discussion, that this discrepancy is due to the way of representing the wavefield in the background theory of seismic interferometry that can produce only wavefields moderately dependent on azimuth and that the mentioned consequence of seismic interferometry can also only make sense in a wavefield moderately dependent on azimuth. Our field experiment with a wavefield dependent on azimuth showed that the consequence of seismic interferometry in the logical framework of the conventional spatial autocorrelation theory is appropriate under such degrees of approximation as the measure proposed in this study, i.e., the deviation of the total dispersion curves is between about 10 and 16 per cent at the maximum from those averaged over azimuth. The acceptance of the retrieval of Green's function gives a proper physical meaning to the complex coherence function: the real part of the elastodynamic Green's function normalized by its zero-offset version. This makes it possible to take a deterministic approach rather than the statistical one on which the conventional spatial autocorrelation method is based and gives fruitful new aspects and perspectives. For example, the formula for the multi-mode case is given and the possibility of exploration of two or three dimensional velocity structures is suggested. [source] SAR imaging using multidimensional continuous wavelet transform and applications to polarimetry and interferometryINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 5 2004E. Colin Abstract Usual SAR imaging process makes the assumption that the reflectors are isotropic and white (i.e., they behave in the same way regardless the angle from which they are viewed and the emitted frequency within the bandwidth). The multidimensional continuous wavelet transform (CWT) in radar imaging was initially developed to highlight the image degradations due to these assumptions. In this article the wavelet transform method is widened to polarimetry and interferometry fields. The wavelet tool is first used for polarimetric image enhancement, then for coherence optimization in interferometry. This optimization by wavelets, compared with the polarimetric one, gives better results on the coherence level. Finally, a combination of both methods is proposed. © 2005 Wiley Periodicals Inc. Int J Imaging Syst Technol, 14, 206,212, 2004; Published online in Wiley Inter-Science (www.interscience.wiley.com). DOI 10.1002/ima.20025 [source] Early stages of protein crystallization as revealed by emerging optical waveguide technologyJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3 2008Attia Boudjemline A highly sensitive method for studying the onset of protein crystallization in real time using an optical-waveguide-based technique is reported. Dual polarization interferometry uses light from sensing and reference waveguides to produce an interference pattern, which when the sensing waveguide is immersed in a protein solution supplies information on the thickness and density of any protein adlayer on the sensing waveguide's surface. This technique provides evidence that crystallization proceeds via large protein aggregates but, more strikingly, shows dramatic light loss from the sensing waveguide at a very early stage during crystallization. The technique proves relatively insensitive to the crystallization of small molecules or poorly formed protein crystals and affords a method of distinguishing crystal formation from the formation of other protein aggregates or salt crystals. The experimental setup currently necessitates crystallization using the batch method, and precipitant mixing at high supersaturation is known to introduce a greater variability compared with methods such as vapour diffusion or dialysis, but first results promise to bridge the paucity of real-time methods available to distinguish the onset of protein crystallization from other forms of aggregation. [source] Coherence and wavefront characterization of Si-111 monochromators using double-grating interferometryJOURNAL OF SYNCHROTRON RADIATION, Issue 3 2010Ana Diaz A study of the coherence and wavefront properties of a pseudo-channel-cut monochromator in comparison with a double-crystal monochromator is presented. Using a double-grating interferometer designed for the hard X-ray regime, the complex coherence factor was measured and the wavefront distortions at the sample position were analyzed. A transverse coherence length was found in the vertical direction that was a factor of two larger for the channel-cut monochromator owing to its higher mechanical stability. The wavefront distortions after different optical elements in the beam, such as monochromators and mirrors, were also quantified. This work is particularly relevant for coherent diffraction imaging experiments with synchrotron sources. [source] Two-dimensional visible synchrotron light interferometry for transverse beam-profile measurement at the SPring-8 storage ringJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2003Mitsuhiro Masaki A two-dimensional visible synchrotron light interferometer has been developed to measure the transverse profile of an electron beam at the SPring-8 storage ring. The new interferometer enables the simultaneous measurement of beam sizes along the major and minor axes and the beam-tilt angle of an assumed elliptical Gaussian distribution. The principle of the interferometer is explained through basic formulae. To calibrate the point-spread function of the interferometer, a simple error model was assumed for disturbances in the amplitude and phase of the light; these disturbances were presumably caused by optical elements, such as mirrors and lenses. The experimental method to determine the parameters in the error model is shown. To verify the two-dimensional profiling capabilities of the interferometer, an electron beam stored in the SPring-8 storage ring operated at various working points was observed. A beam broadening from 20 to 120,µm in the vertical direction and changes in the beam-tilt angle were clearly observed at working points close to the differential resonance. However, the vertical spatial resolution is limited by the available vertical separation of the apertures of the diffracting mask because of the narrow aperture of the upstream vacuum duct. [source] Multiple-beam X-ray interferometry for phase-contrast microtomographyJOURNAL OF SYNCHROTRON RADIATION, Issue 1 2001Ulrich Bonse The first successful operation of an X-ray interferometer under conditions of non-planar three-beam diffraction for phase-contrast X-ray microtomography is reported. Intrinsic phase differences of the reflections used cancel from the three-dimensional phase image of the specimen. With simultaneous hkl and reflections of a synchrotron radiation beam in a side-by-side geometry, the size of the usable field of view is doubled and the investigated specimen volume is increased by a factor of four. As an example, the reconstructed slice of a mouse kidney is shown in phase contrast at 71,keV. Optimized choices of three-beam reflections and matching interferometer geometries useful for applications are presented. [source] | |||||||||||||||||||||||||||||||||||||