Two-dimensional X-ray Detector Research Articles

Simultaneous quick-scanning X-ray absorption spectroscopy and X-ray diffraction

The existing setup for time-resolved quick-scanning X-ray absorption spectroscopy (QEXAFS) at beamline P64 at the PETRA III storage ring is complemented by new infrastructure suited for the collection of X-ray diffraction data simultaneously to the QEXAFS experiment. In particular, the sinusoidal periodic movements of the quick-EXAFS mono-chromator are modified in such a way, that an energy plateau with approximately constant energy over a certain time is created in the pre-edge region of the absorption edge of interest. By employing a properly defined trigger signal in this time, the exposure of a two-dimensional X-ray detector placed behind the sample is actuated, thus allowing to collect an X-ray diffraction pattern over a certain angular range as defined by the actual X-ray energy and the position of the 2D-detector. Details of the new setup as well as exemplary results obtained during the solvothermal synthesis of ZnO nanoparticles and the bcc-fcc phase transition of iron at elevated temperatures are presented.

X-ray imaging of moving objects using on-chip TDI and MDX methods with single photon counting CdTe hybrid pixel detector

X-ray imaging of moving objects using line detectors remains the most popular method of object content and structure examination with a typical resolution limited to 0.4–1 mm. Higher resolutions are difficult to obtain as, for the detector in the form of a single pixel row, the narrower the detector is, the lower the image Signal to Noise Ratio (SNR). This is because, for smaller pixel sizes, fewer photons hit the pixel in each time unit for a given radiation intensity.To overcome the trade-off between the SNR and spatial resolution, a two-dimensional sensor, namely a pixel matrix can be used. Imaging of moving objects with a pixel matrix requires time-domain integration (TDI). Straightforward TDI implementation is based on the proper accumulation of images acquired during consecutive phases of an object’s movement. Unfortunately, this method is much more demanding regarding data transfer and processing. Data from the whole pixel matrix instead of a single pixel row must be transferred out of the chip and then processed.The alternative approach is on-chip TDI implementation. It takes advantage of photons acquired by multiple rows (a higher SNR), but generates similar data amount as a single pixel row and does not require data processing out of the chip. In this paper, on-chip TDI is described and verified by using a single photon counting two-dimensional (a matrix of 128 × 192 pixels) CdTe hybrid X-ray detector with the 100 µm × 100 µm pixel size with up to four energy thresholds per pixel. Spatial resolution verification is combined with the Material Discrimination X-ray (MDX) imaging method.

Observation of parametric X-ray radiation for the asymmetric Laue geometry

Angular distributions of parametric X-ray radiation from 255-MeV electrons in a thin Si crystal have been investigated for asymmetric Laue geometries using an imaging plate as a two-dimensional position-sensitive X-ray detector. The peak intensities of parametric X-ray radiation observed for (111) and (1¯1¯ 1) reflections, normalized by taking into account the effective target thickness and the transmission fraction of X-rays in the crystal, coincided within several percent. A large intensity difference depending on the asymmetry parameter, which is predicted by a dynamical theory dealing with the asymmetric Laue geometry, was not observed under the present experimental conditions. This indicates that the dependence of angular distributions of parametric X-ray radiation on the asymmetry parameter is negligibly weak, i.e., that it can be well explained by the well-established kinematical theory and dynamical theory as well as those for symmetric Laue and Bragg geometries.

Development of a half-cell for x-ray structural analysis of liquid electrolytes in rechargeable batteries.

A half-cell of the rechargeable Li-ion battery was developed to characterize an electrolyte structure using high energy x-ray total scattering measurements in combination with a two-dimensional x-ray detector. The scattering pattern consisted of strong Bragg peaks from electrodes and diffuse scatterings from sapphire windows, in addition to a weak halo pattern from the electrolyte. By selectively removing the signals of the electrodes and windows using specific numerical procedures, we could successfully extract the structural information of the electrolyte, which was in reasonable agreement with the reference data obtained from the electrolyte in a glass capillary. The present demonstration with a half-cell is expected to shed new light on operand characterization of the electrolyte structure during charging and discharging.

Development of integration-type silicon-on-insulator monolithic pixel detectors using a float zone silicon

In this paper, we describe the development of monolithic pixel detectors using silicon-on-insulator (SOI) technology for a rapid X-ray residual stress measurement system. Conventional two-dimensional X-ray detectors are not suitable for rapid X-ray residual stress measurement because of their large pixel size and slow readout. For this reason, we developed highly sensitive SOI monolithic pixel detectors that are made up of smaller pixels and can provide a more rapid X-ray residual stress measurement readout. The detectors are fabricated using a 0.2μm CMOS fully-depleted SOI process (Lapis Semiconductor Co., Ltd). The SOI wafer is made by directly bonding a thick, high-resistivity Si wafer and a low-resistivity Si CMOS wafer. The process does not make use of mechanical bump bonding. We developed an integration-type SOI pixel detector, INTPIX4, for a rapid X-ray residual stress measurement system; it uses a float zone (FZ) or Czochralski (Cz) silicon wafer. Cz SOI detectors have been in use since 2005. After 2011, FZ SOI detectors were successfully fabricated. In this paper, we state recent progresses and test results of the SOI monolithic pixel detector using a FZ silicon and compare them with the results obtained using the Cz detector.

Microsecond time-resolved X-ray diffraction for the investigation of fatigue behavior during ultrasonic fatigue loading.

A new method based on time-resolved X-ray diffraction is proposed in order to measure the elastic strain and stress during ultrasonic fatigue loading experiments. Pure Cu was chosen as an example material for the experiments using a 20 kHz ultrasonic fatigue machine mounted on the six-circle diffractometer available at the DiffAbs beamline on the SOLEIL synchrotron facility in France. A two-dimensional hybrid pixel X-ray detector (XPAD3.2) was triggered by the strain gage signal in a synchronous data acquisition scheme (pump-probe-like). The method enables studying loading cycles with a period of 50 µs, achieving a temporal resolution of 1 µs. This allows a precise reconstruction of the diffraction patterns during the loading cycles. From the diffraction patterns, the position of the peaks, their shifts and their respective broadening can be deduced. The diffraction peak shift allows the elastic lattice strain to be estimated with a resolution of ∼10-5. Stress is calculated by the self-consistent scale-transition model through which the elastic response of the material is estimated. The amplitudes of the cyclic stresses range from 40 to 120 MPa and vary linearly with respect to the displacement applied by the ultrasonic machine. Moreover, the experimental results highlight an increase of the diffraction peak broadening with the number of applied cycles.

Analysis of powder diffraction data collected with synchrotron X-ray and multiple 2D X-ray detectors applying a beta-distribution peak profile model

A powder diffraction measurement system constructed on a beam-line BL5S2 at Aichi Synchrotron Radiation Center in Seto, Japan, has been modified for extensive use of two-dimensional (2D) X-ray detectors. Four flat 2D detectors are currently mounted on the movable stages on supporting rods radially attached to the 2Θ-wheel of the goniometer with the interval of 25°. The 2D powder diffraction intensity data are reduced to conventional 1D format of powder diffraction data by the method based on averaging of the pixel intensities with geometrical corrections, which also enables evaluation of standard uncertainties about the reduced intensity data. The 1D powder diffraction data of a 0.1 mm-capillary LaB6 (NIST SRM660b) sample obtained at the camera length of 340 mm have shown almost symmetric peak profile with slight asymmetry simulated by a beta-distribution profile function.

Single-shot full strain tensor determination with microbeam X-ray Laue diffraction and a two-dimensional energy-dispersive detector.

The full strain and stress tensor determination in a triaxially stressed single crystal using X-ray diffraction requires a series of lattice spacing measurements at different crystal orientations. This can be achieved using a tunable X-ray source. This article reports on a novel experimental procedure for single-shot full strain tensor determination using polychromatic synchrotron radiation with an energy range from 5 to 23 keV. Microbeam X-ray Laue diffraction patterns were collected from a copper micro-bending beam along the central axis (centroid of the cross section). Taking advantage of a two-dimensional energy-dispersive X-ray detector (pnCCD), the position and energy of the collected Laue spots were measured for multiple positions on the sample, allowing the measurement of variations in the local microstructure. At the same time, both the deviatoric and hydrostatic components of the elastic strain and stress tensors were calculated.

Angular distributions of parametric X-ray radiation from a diamond crystal

Angular distributions of parametric X-ray radiation (PXR) from 255MeV electrons incident on a 50μm thick diamond crystal are presented. Almost all experiments on the angular distributions of PXR have been performed using Si crystals. The purpose of the present work is to extend this research to diamond crystals. An imaging plate was adopted as a two-dimensional position-sensitive X-ray detector, and high-quality PXR angular distribution data were successfully obtained. The measured PXR angular distributions were compared with those predicted theoretically and good agreement was obtained. The cause of the slight difference observed around the center position (Bragg direction) is also discussed.

X-Ray Stress Measurement of Austenitic Stainless Steel with cosα Method and Two-Dimensional X-Ray Detector

This paper describes a fundamental experiment on X-ray stress measurement of austenitic stainless steel (JIS SUS316L) with a new equipment which was developed in this study. An image plate (IP) as a two-dimensional X-ray detector and the cosα method as a principle of the measurement of stress were used in it. An experiment was conducted with CrKβ characteristic X-ray and γFe-311 diffraction line, and the results were compared to those that were obtained with the conventional sin2ψ method under the similar X-ray conditions. It was found that the accuracy of stresses obtained with the equipment developed are almost as same as those of the sin2ψ method. However, the measuring time can be shorten by several times by using it.

Experimental estimation of uncertainties in powder diffraction intensities with a two-dimensional X-ray detector

A method to obtain both one-dimensional powder diffraction intensities I(2θ) and statistical uncertainties σ(2θ) from the data collected with a flat two-dimensional X-ray detector is proposed. The method has been applied to analysis of the diffraction data of fine quartz powder recorded with synchrotron X-ray. The profile and magnitude of the estimated uncertainties σ(2θ) have shown that the effects of propagation of the errors in 2θ are dominant as the uncertainties about the observed intensity values I(2θ). The powder diffraction intensity data I(2θ), including nine reflection peaks have been analyzed by the Rietveld method incorporating the experimentally estimated uncertainties σ(2θ). The observed I(2θ) data have been reproduced with a symmetric peak profile function (Rwp = 0.84 %), and no significant peak shifts from calculated locations have been detected as compared with the experimental errors. The optimized values of the lattice constants of the quartz sample have nominally been estimated at a = 4.9131(4) Å and c = 5.4043(2) Å, where the uncertainties in parentheses are evaluated by the Rietveld optimization based on the estimated uncertainties σ(2θ) for intensities I(2θ). It is likely that reliability of error estimation about unit-cell dimensions has been improved by this analytical method.

BINoculars: data reduction and analysis software for two-dimensional detectors in surface X-ray diffraction

BINoculars is a tool for data reduction and analysis of large sets of surface diffraction data that have been acquired with a two-dimensional X-ray detector. The intensity of each pixel of a two-dimensional detector is projected onto a three-dimensional grid in reciprocal-lattice coordinates using a binning algorithm. This allows for fast acquisition and processing of high-resolution data sets and results in a significant reduction of the size of the data set. The subsequent analysis then proceeds in reciprocal space. It has evolved from the specific needs of the ID03 beamline at the ESRF, but it has a modular design and can be easily adjusted and extended to work with data from other beamlines or from other measurement techniques. This paper covers the design and the underlying methods employed in this software package and explains how BINoculars can be used to improve the workflow of surface X-ray diffraction measurements and analysis.

Combined linear polarization and angular distribution measurements of x-rays for precise determination of multipole-mixing in characteristic transitions of high-Z systems

By applying novel-type position sensitive x-ray detectors as Compton polarimeters we recently performed a study of the linear polarization of Lyman- radiation following radiative electron capture into initially bare uranium ions. It was found that a model-independent determination of the ratio of the E1 and M2 transition amplitudes, and consequently of the corresponding transition rates, is feasible by combining the linear polarization data with a measurement of the angular distribution of the emitted radiation. In this work a detailed description of the underlying experimental technique for combined measurements of the linear polarization and the angular distribution of characteristic transitions in high-Z ions is presented. Special emphasis is given to the application of two, two-dimensional position-sensitive x-ray detectors for Compton polarimetry of hard x-rays. Moreover, we demonstrate the polarimeter efficiency of such detector systems can be significantly improved if events, where the charge is spread over neighboring segments, are reconstructed to be used in the polarization analysis.

Nebula: reconstruction and visualization of scattering data in reciprocal space.

Two-dimensional solid-state X-ray detectors can now operate at considerable data throughput rates that allow full three-dimensional sampling of scattering data from extended volumes of reciprocal space within second to minute time-scales. For such experiments, simultaneous analysis and visualization allows for remeasurements and a more dynamic measurement strategy. A new software, Nebula, is presented. It efficiently reconstructs X-ray scattering data, generates three-dimensional reciprocal space data sets that can be visualized interactively, and aims to enable real-time processing in high-throughput measurements by employing parallel computing on commodity hardware.

Compton polarimetry using double-sided segmented x-ray detectors

Hard x-ray polarimetry of radiation emitted in collisions of heavy ions, electrons or photons with matter provides detailed information on the collision dynamics as well as of the atomic structure in the presence of extreme field strengths. Moreover, it also opens a route for polarization diagnosis of spin-polarized ion and electron beams which, for example, might be useful in future parity non-conservation studies. Owing to recent progress in the development of highly segmented solid-state detectors, a novel type of polarimeter for the hard x-ray regime has become available. Applied as Compton polarimeters, two-dimensional position-sensitive x-ray detectors now allow for precise and efficient measurements of x-ray linear polarization properties. In this report recent polarimetry studies using such detector systems are reviewed.

デバイリングのフーリエ解析による鉄鋼材料のX線応力測定

In this study, X-ray stress measurements of ferritic steel based on Fourier analysis are conducted. Taira et al. developed the cosα method for X-ray stress measurements using a two-dimensional X-ray detector. Miyazaki et al. reported that the cosα method can be described more concisely by developing the Fourier series (the Fourier analysis method). The Fourier analysis method is expected to yield the stress measurement with an imperfect Debye-Scherrer ring and there is a possibility that the materials evaluation is different compared with the conventional method, that is, the sin2ψ method. In the Fourier analysis method, the strain measured by X-rays is developed as a Fourier series, and all the plane-stress components can be calculated from the Fourier series. In this study, the normal stress calculation was confirmed. In addition, the Fourier-analysis and cosα methods were used for X-ray stress measurements during a four-point bending test on a S45C test piece, and the effectiveness of the Fourier analysis method was confirmed. It was found that the experimental results from the Fourier analysis and cosα methods were nearly identical. In addition, the measurement accuracies of both the methods were equivalent.

On the estimation of statistical uncertainties on powder diffraction and small-angle scattering data from two-dimensional X-ray detectors

Optimal methods are explored for obtaining one-dimensional powder pattern intensities from two-dimensional planar detectors with good estimates of their standard deviations. Methods are described to estimate uncertainties when the same image is measured in multiple frames as well as from a single frame. The importance of considering the correlation of diffraction points during the integration and the resampling process of data analysis is shown. It is found that correlations between adjacent pixels in the image can lead to seriously overestimated uncertainties if such correlations are neglected in the integration process. Off-diagonal entries in the variance–covariance (VC) matrix are problematic as virtually all data processing and modeling programs cannot handle the full VC matrix. It is shown that the off-diagonal terms come mainly from the pixel-splitting algorithm used as the default integration algorithm in many popular two-dimensional integration programs, as well as from rebinning and resampling steps later in the processing. When the full VC matrix can be propagated during the data reduction, it is possible to get accurate refined parameters and their uncertainties at the cost of increasing computational complexity. However, as this is not normally possible, the best approximate methods for data processing in order to estimate uncertainties on refined parameters with the greatest accuracy from just the diagonal variance terms in the VC matrix is explored.

Breakthroughs in hard X-ray diffraction: towards a multiscale science approach in heterogeneous catalysis.

Breakthroughs in hard X-ray diffraction: towards a multiscale science approach in heterogeneous catalysis.

New method for measuring beam profiles using a parametric X-ray pinhole camera

We propose a new method for measuring electron beam profiles using parametric X-ray radiation. In this method, a pinhole is placed between the source of parametric X-ray radiation and a two-dimensional X-ray detector, and the beam profile can be reconstructed on the detector, i.e., based on the principle of a pinhole camera. The profiles are in good agreement with the results obtained using a standard method with optical transition radiation. This method may prove useful to measure profiles of electron beams with short bunch lengths in recent advanced linear accelerators. • We propose a new method for measuring beam profiles using parametric X-ray radiation. • The proposed method is based on the principle of a pinhole camera. • We have succeeded in performing a proof-of-principle experiment. • The proposed method may be useful for beam monitors in recent advanced accelerators.

Evaluation of data-acquisition front ends for handling high-bandwidth data from X-ray 2D detectors: A feasibility study

Two-dimensional (2D) X-ray detectors are indispensable for synchrotron radiation and X-ray free-electron laser experiments, such as coherent X-ray imaging, spectroscopy, and time-resolved experiments. In these experiments, special, temporal, or photon-energy information is projected onto the surface of a 2D X-ray detector, and it is generally accepted that detectors with a larger number of pixels and a higher dynamic range will provide better information on the sample. An example of a high-performance application in this area is SOPHIAS (Silicon-On-Insulator Photon Imaging Array Sensor), which is a next generation detector under development at the SPring-8 facility, Japan. Since such systems demand a high-bandwidth front end for data acquisition (DAQ), a prototype front end for SOPHIAS is also under development. Here, we have performed a feasibility study of the prototype front end using an evaluation board, which consists of an FPGA (field-programmable gate array) with an FMC (FPGA mezzanine card) interface to support various physical layers of sensor readout modules and back-end DAQ. The bandwidths were measured for various combinations of protocols and physical layers. In many photon science applications, scalability from a single module to many modules is important, so a compact desktop-type DAQ system was also evaluated. Measurements of the bandwidth using the evaluation board indicated that an effective bandwidth of 9 Gbps and 16 Gbps was achieved using SFP+ (Small Form-factor Pluggable Plus) with XAUI (X (ten) Attached Unit Interface) and PCI Express (Peripheral Component Interconnect Express), respectively.