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Nuclear instruments & methods in physics research / A 1047, 167904 (2023). doi:10.1016/j.nima.2022.167904, In past years efforts have concentrated on the development of arrays of Silicon Drift Detectors for X-ray spectroscopy. This is in stark contrast to the little effort that has been devoted to the improvement of germanium detectors, in particular for synchrotron applications. Germanium detectors have better energy resolution and are more efficient in detecting high energy photons than silicon detectors. In this context, the detector consortium of the European project LEAPS-INNOV has set an ambitious R&D program devoted to the development of a new generation of multi-element monolithic germanium detectors for X-ray detection. In order to improve the performance of the detector under development, simulations of the different detector design options have been performed. In this contribution, the efforts in terms of R&D are outlined with a focus on the modelization of the detector geometry and first performance results. These performance results show that a signal-to-background ratio larger than 1000 can be achieved in the energy range of interest from 5 keV to 100 keV., Published by North-Holland Publ. Co., Amsterdam

The PERCIVAL detector is a CMOS imager designed for the soft X-ray regime at photon sources. Although still in its final development phase, it has recently seen its first user experiments: ptychography at a free-electron laser, holographic imaging at a storage ring and preliminary tests on X-ray photon correlation spectroscopy. The detector performed remarkably well in terms of spatial resolution achievable in the sample plane, owing to its small pixel size, large active area and very large dynamic range; but also in terms of its frame rate, which is significantly faster than traditional CCDs. In particular, it is the combination of these features which makes PERCIVAL an attractive option for soft X-ray science.

14th International Conference on Synchrotron radiation Instrumentation, (SRI 2021), Hamburg, Germany, 28 Mar 2022 - 1 Apr 2022; Journal of physics / Conference Series 2380(1), 012093 (2022). doi:10.1088/1742-6596/2380/1/012093, An X-ray imager is being developed for use in diffraction-limited Synchrotron Rings and Continuous Wave Free Electron Lasers. The imager is named CoRDIA (COntinuous Readout Digitising Imager Array) and aims at achieving continuous operation at a frame rate in excess of 100kHz. Other goals include single-photon sensitivity at 12 keV (or below), a full well in excess of 10k photon/pixel/image, and a 100μm pixel pitch. The detector ASIC will be compatible with multiple sensor materials to cover different energy ranges. Exploratory prototypes of the readout ASIC (basic circuital blocks) have been manufactured in in TSMC 65nm technology: they are presenltly under test., Published by IOP Publ., Bristol

X-ray computed micro-tomography (μCT) is one of the most advanced and common non-destructive techniques in the field of medical imaging and material science. It allows recreating virtual models (3D models), without destroying the original objects, by measuring three-dimensional X-ray attenuation coefficient maps of samples on the (sub) micrometer scale. The quality of the images obtained using μCT is strongly dependent on the performance of the associated X-ray detector i.e. to the acquisition of information of the X-ray beam traversing the patient/sample being precise and accurate. Detectors for μCT have to meet the requirements of the specific tomography procedure in which they are going to be used. In general, the key parameters are high spatial resolution, high dynamic range, uniformity of response, high contrast sensitivity, fast acquisition readout and support of high frame rates. At present the detection devices in commercial μCT scanners are dominated by charge-coupled devices (CCD), photodiode arrays, CMOS acquisition circuits and more recently by hybrid pixel detectors. Monolithic CMOS imaging sensors, which offer reduced pixel sizes and low electronic noise, are certainly excellent candidates for μCT and may be used for the development of novel high-resolution imaging applications. The uses of monolithic CMOS based detectors such as the PERCIVAL detector are being recently explored for synchrotron and FEL applications. PERCIVAL was developed to operate in synchrotron and FEL facilities in the soft X-ray regime from 250 eV to 1 keV and it could offer all the aforementioned technical requirements needed in μCT experiments. In order to adapt the system for a typical tomography application, a scintillator is required, to convert incoming X-ray radiation (∼ tens of KeV) into visible light which may be detected with high efficiency. Such a taper-based scintillator was developed and mounted in front of the sensitive area of the PERCIVAL imager. In this presentation we will report the setup of the detector system and preliminary results of first μCTs of reference objects, which were performed in the TomoLab at ELETTRA.

In this paper, we are presenting the results of the first test of the Percival P2M-FSI detector with tender x-rays photons at a synchrotron beamline. Percival is a monolithic CMOS Imager for detection of x-rays in Synchrotron Rings and Free Electron Lasers: the Front-Side-Illuminated (FSI) version of the detector has been proven able to successfully distinguish tender (2keV) x-ray single photons.

High brilliance synchrotrons and FELs require high performing detector systems to realise their full potential. High dynamic range, low noise and high frame rate are all of great importance. In this paper we present first optical characterization results of the P2M CMOS sensor, designed for soft X-ray detection at such facilities. Previous work is summarised and an overview of the sensor is presented. Test results for the sensor’s column-parallel ADC and readout chain are presented, and first test results for the pixel acquired using the Photon Transfer Curve (PTC) method are shown. Finally, an outline of future work is provided.

The PERCIVAL collaboration to develop a soft X-ray imager able to address the challenges of high brilliance light sources, such as new-generation synchrotrons and Free Electron Lasers, has reached one of its major milestones: a full 2-MegaPixel (P2M) system (uninterrupted 4 × 4 cm2 active area) has already seen its first light.Smaller prototypes of the device, a monolithic active pixel sensor based on CMOS technology, have already been fully characterised, and have demonstrated high frame rate, large dynamic range, and relatively high quantum efficiency.The PERCIVAL modular layout allows for clover-leaf like arrangement of up to four P2M systems. Moreover, it will be post-processed in order to achieve a high quantum efficiency in its primary energy range (250 eV to 1 keV).We will present the P2M system, its status and newest results, bring these in context with achieved prototype performance, and outline future steps.

A photon-counting hybrid pixel detector (Medipix-1) has been characterized using a synchrotron X-ray source. The detector consists of a readout ASIC with 64 � 64 independent photon-counting cells of 170 � 170mm 2 pitch, bumpbonded to a 300mm thick silicon sensor, read out by a PCIbus-based electronics, and a graphical user interface (GUI) software. The intensity and the energy tunability of the X-ray source allows characterization of the detector in the time, space, and energy domains. The system can be read out on external trigger at a frame rate of 100 Hz with 3 ms exposure time per frame. The detector response is tested up to more than 7 � 10 5 detected events/pixel/s. The point-spread response shows o2% crosstalk between neighboring pixels. Fine scanning of the detector surface with a 10mm beam reveals no loss in sensitivity between adjacent pixels as could result from charge sharing in the silicon sensor. Photons down to 6 keV can be detected after equalization of the thresholds of individual pixels. The obtained results demonstrate the advantages of photon-counting hybrid pixel detectors and particularly of the Medipix-1 chip for a wide range of X-ray imaging applications, including those using synchrotron X-ray beams. r 2001 Published by Elsevier Science B.V.

Intense, coherent X-ray pulses from a free-electron laser can be used to obtain high-resolution morphology of individual sub-micrometre particles in their native state, while at the same time their composition is analysed by mass spectrometry. Aerosol particles are of importance in fields as diverse as materials engineering, toxicology and climate change, yet it is difficult to analyse the structure and properties of these materials in their native environment. This paper reports an in situ method for imaging individual sub-micrometre-sized particles to nanometre resolution in flight using intense X-ray pulses from the Linac Coherent Light Source free-electron laser. The technique can also simultaneously carry out compositional analysis using time-of-flight mass spectrometry. The morphology of micrometre-size particulate matter is of critical importance in fields ranging from toxicology1 to climate science2, yet these properties are surprisingly difficult to measure in the particles’ native environment. Electron microscopy requires collection of particles on a substrate3; visible light scattering provides insufficient resolution4; and X-ray synchrotron studies have been limited to ensembles of particles5. Here we demonstrate an in situ method for imaging individual sub-micrometre particles to nanometre resolution in their native environment, using intense, coherent X-ray pulses from the Linac Coherent Light Source6 free-electron laser. We introduced individual aerosol particles into the pulsed X-ray beam, which is sufficiently intense that diffraction from individual particles can be measured for morphological analysis. At the same time, ion fragments ejected from the beam were analysed using mass spectrometry, to determine the composition of single aerosol particles. Our results show the extent of internal dilation symmetry of individual soot particles subject to non-equilibrium aggregation, and the surprisingly large variability in their fractal dimensions. More broadly, our methods can be extended to resolve both static and dynamic morphology of general ensembles of disordered particles. Such general morphology has implications in topics such as solvent accessibilities in proteins7, vibrational energy transfer by the hydrodynamic interaction of amino acids8, and large-scale production of nanoscale structures by flame synthesis9.

The spatial resolution of a single-photon-resolving integrating system has been improved using a non-linear charge interpolation approach. The resolution limit for a 20 µm-pitch sensor is presented., A synchrotron beam has been used to test the spatial resolution of a single-photon-resolving integrating readout-chip coupled to a 320 µm-thick silicon strip sensor with a dedicated readout system. Charge interpolation methods have yielded a spatial resolution of σx ≃ 1.8 µm for a 20 µm-pitch strip.

A charge integrating readout chip for silicon strip sensors is currently under development at Paul Sherrer Institut. The goal of the project is to provide a readout system that can sustain, through charge integration and automatic gain switching, the instantaneous many-photon deposition typical of the forthcoming XFEL machines. Nevertheless, a charge integrating readout with single photon sensitivity presents several features that can be exploited in many Synchrotron source applications: the possibility of a higher position resolution, the high photon rate capabilities and the possibility to detect low energy photon. A prototype of the readout chip (ROC) has been integrated with a strip detector and with a dedicated DAQ electronic, and it has been tested at the SYRMEP beam line (ELETTRA, Trieste). This work presents the readout chip and shows the results of the beam line tests in terms of spatial resolution and rate capabilities.

The European X-ray free electron laser is a new research facility currently under construction in Hamburg, Germany. Typical for XFEL machines is the high peak brilliance several orders of magnitudes above existing synchrotron facilities. With a pulse length below 100 fs and an extremely high luminosity of 30,000 flashes per second the European XFEL will have a worldwide unique time structure that enables researchers to record movies of ultrafast processes. This demands the development of new detectors tailored to the requirements imposed by the experiments while complying with the machine specific operation parameters. The adaptive gain integrating pixel detector (AGIPD) is one response to the need for large 2D detectors, able to cope with the 5 MHz repetition rate, as well as with the high dynamic range needed by XFEL experiments (from single photons to 104 12 keV photons per pixel per pulse). In addition, doses up to 1 GGy over three years are expected.

AGIPD (Adaptive Gain Integrating Pixel Detector) is currently under development for the European X-ray Free Electron Laser (XFEL). It is a hybrid pixel detector with a specifi cally developed readout chip bump bonded to a silicon sensor. The chip is being designed in IBM 0.13 µm CMOS technology. This paper is focused on the readout chip design. The main challenges for this chip are: the high dynamic range (1 - 1.4× 10 4 ) with single photon sensitivity, the long storage chain (≥ 200) with a long hold time (99 ms), and the high radiation dose (up to 100 MGy). A charge integrating amplifier with a gain adaptive to the number of in coming photons is combined with a correlated double sampling (CDS) buffer to achieve the required dynamic range and single photon sensitivity. Several techniques are implemented in the storage cell design in order to reduce lea kage current and signal-dependent charge injection. Four prototype chips have been designed for testing the performance of the implemented switches, capacitors, amplifiers, storage cells and periphery circuitry. The recently submit ted test chip has a 16× 16 pixel matrix , 100 storage cells in each pixel and a periphery circuitry for accessing and contr olling the pixels and storage cells.

Over the last decade, synchrotron radiation sources have seen a significant increase in brilliance, and the advent of free electron lasers has made entire new research fields accessible to investigations with X-rays. These advances in light source capabilities have resulted not only in a host of scientific advances and discoveries, but also in a need for a new generation of X-ray imaging detectors that can match the sources' capabilities in terms of frame rate and image dynamic range while recording image information with fine granularity over a large - preferably uninterrupted - (multi)megapixel area with single-photon sensitivity. Developing such next-generation imagers is both costly and time-consuming, and the requirements at many photon science facilities are similar enough to invite a collaborative effort. The Percival ("Pixellated Energy Resolving CMOS Imager, Versatile And Large") imager is being developed by a collaboration of DESY, Rutherford Appleton Laboratory (RAL), Elettra, and Diamond Light Source (DLS) to answer this need for the soft X-ray regime

We report about the activity and progress on the development of TSV edgeless detectors at DESY. One part of the development is Through Silicon Via (TSV) technology for the Medipix3RX readout chip (ROC). TSV technology is a concept of connecting readout chips to readout electronics. Instead of wire-bonding which introduces a large dead area, TSV enables connection through the ROC itself. By replacing wire-bonding with TSV, the dead space between detector modules will be reduced from around 7 mm to only 1.6 mm. The thickness of the wafer will be 200 μ m, with a via diameter of 60 μ m. Inside of the via, a 5 μ m thick copper layer will be used as a conducting layer. On the back side of the chip a Redistribution Layer (RDL) will be deposited. For the RDL structure, 5 μ m thick copper with 40 μ m wide conductive lines will be used. Bump bonding of the sensor plus ROC assembly to ceramic readout board will be optimized in terms of material and bonding temperature. The second part of the project is the development of the edgeless sensor units using active edge sensor technology. Active edge sensors have been simulated with Synopsys TCAD for different polarities including p-on-n, p-on-p, n-on-p and n-on-n with p-spray or p-stop for different thicknesses from 150 μ m to 500 μ m. Results show that the bending of the electric field close to the active edge is leading to image distortion on the sensor edge. In addition, the current design of active-edge sensors shows very poor radiation hardness. We are currently working on the development of a radiation hard active-edge sensor with optimized imaging quality. The final goal of this development is to make Large Area Medipix Detector (LAMBDA) with TSV edgeless units.

Considerable interest has been manifested for the use of high-brilliance X-ray synchrotron sources and X-ray Free-Electron Lasers for the investigation of samples.

We report the results of a series of X- and γ-ray measurements on a 3 × 3 mm 2 , 2 mm thick CdZnTe detector carried out at the HASYLAB and ESRF synchrotron radiation facilities. The detector energy response function was found to be linear over the energy range 10–100 keV with an average rms non-linearity of 0.6%, consistent with statistics. Under full area illumination, the FWHM energy resolution was 270 eV at 5.9 keV and rises to 930 eV at 59.54 keV. Under pencil beam illumination, the measured energy resolution at 10 keV was 310 eV FWHM and rises to ∼1000 eV at 100 keV. At 60 keV the resolution was found to be ∼30% lower than that measured under uniform illumination, indicating a degree of non-uniform crystallinity and stoichiometry in the bulk. For energies

A unique combination of in situ synchrotron x-ray diffraction and in situ micro-Raman spectroscopy was used to study the growth process of YBa2Cu3O6+x films obtained by metal organic decomposition using trifluoroacetate precursor on LaAlO3 substrates. The techniques give complementary information: x-ray diffraction gives insight into the structural growth, whereas micro-Raman spectroscopy gives information of the chemical composition with additional information on the texture. To perform both experiments in situ, a special high-temperature process chamber was designed.

A dispersion-compensation method to remove the cube-size effect from the resolution function of diced analyzer crystals using a position-sensitive two-dimensional pixel detector is presented. For demonstration, a resolution of 23 meV was achieved with a spectrometer based on a 1 m Rowland circle and a diced Si(555) analyzer crystal in a near-backscattering geometry, with a Bragg angle of 88.5 degrees . In this geometry the spectrometer equipped with a traditional position-insensitive detector provides a resolution of 190 meV. The dispersion-compensation method thus allows a substantial increase in the resolving power without any loss of signal intensity.

The atomic surface structure of single terminated SrTiO3(0 0 1) (1 × 1) is investigated employing surface X-ray diffraction. In order to obtain these surfaces a special treatment is needed consisting of chemical etching and annealing. Since this is done in an aqueous and subsequently oxygen environment, after which the crystals are kept at ambient conditions, the surface is studied in air. Crystal truncation rods are measured and several models that are proposed in literature in recent years are tested against the experimental data. These models include surface rumpling, low temperature-like distortions, strontium adatom and lateral displacement distortions for both TiO2 and SrO-terminated surfaces. None of these models represents the data very accurately. A much better fit to the experimental results is obtained by using a model in which a TiO2-terminated crystal is covered by an oxygen layer.

Films of BaTiO3ranging from 20 nm to 300 nm in thickness were grown with pulsed laser deposition on Nb:SrTiO3. The quality of the layers was investigated using atomic force microscopy, X-ray reflectivity and X-ray diffraction. Both the micrographs and the X-ray reflectivity spectra indicate a smooth surface of the layers. The X-ray diffraction profiles measured using synchrotron radiation show features characteristic for highly crystalline thin films. The application of an external electric field parallel to thecaxis changes anhklreflection of BaTiO3to anhk\bar{l} reflection. Due to the anomalous dispersion, the intensities of these two reflections are not equal and the atomic displacements can be determined from the intensity differences. The electric field-induced intensity changes can be as large as a few percent, which makes data collection from a 100 nm film using CuKα radiation from an X-ray tube feasible. The ΔI/Ivalues of a number of reflections from the 20 and 50 nm films were measured using synchrotron radiation. The observed ΔI/Ivalues were in good agreement with the intensity changes expected for polarization switching in the bulk.

We present the results of a series of X-ray measurements on several prototype TlBr detectors. The devices were fabricated from mono-crystalline material and were typically of size 2.7×2.7×0.8 mm3. The material is extremely pure, having impurity concentrations

The PERCIVAL ("Pixelated Energy Resolving CMOS Imager, Versatile and Large") is a collaboration of DESY, RAL/STFC, ELETTRA, and DLS to develop a monolithic active pixel sensor (MAPS) to provide a suitable detector for photon science for the photon energy regime between 250 eV and 1 keV. An important performance parameter is the spatial resolution which can be inferred from the Modulation Transfer Function (MTF). The MTF measures in optical systems the relative contrast of a pattern in function of the spatial frequency. With a back-thinned and back-illuminated PERCIVAL prototype chip, dedicated MTF evaluation data were taken at Elettra's TwinMic Beamline in March 2014 at a photon energy of 535 eV. We will present our MTF derivation approaches together with MTF results for 3 pixel types of the irradiated test sensor.

Replacing planar circuits with vertically integrated ones allows to increment circuit functionalities on a given silicon area, while avoiding some of the problems associated with aggressively scaled technology nodes. This is particularly true for applications likely to subject circuits to high doses of ionizing radiation (such of x-ray detectors to be used in synchrotron rings and Free Electron Lasers), since the degradation mechanisms of some of the innovative materials to be used in most recent nodes have not been fully characterized yet. In this paper, an evolution is presented for the readout ASIC of a pixelated x-ray detector to be used for such applications. The readout circuit is distributed in a stack of two vertically interconnected tiers, thus doubling the circuitry resident in each pixel without increasing the pixel pitch (and thus compromising spatial resolution of the detector). A first prototype has been designed and manufactured, using a commercial 130 nm CMOS technology. Design issues are discussed, along with preliminary characterization results.

AGIPD is a hybrid pixel X-ray detector developed by a collaboration between Deutsches Elektronen-Synchrotron (DESY), Paul-Scherrer-Institute (PSI), University of Hamburg and the University of Bonn. The detector is designed to comply with the requirements of the European XFEL. The radiation tolerant Application Specific Integrated Circuit (ASIC) is designed with the following highlights: high dynamic range, spanning from single photon sensitivity up to 104 × 12.4 keV photons, achieved by the use of dynamic gain switching, auto-selecting one of 3 gains of the charge sensitive pre-amplifier. To cope with the unique features of the European XFEL source, image data is stored in 352 analogue memory cells per pixel. The selected gain is stored in the same way and depth, encoded as one of 3 voltage levels. These memories are operated in random-access mode at 4.5MHz frame rate. Data is read out on a row-by-row basis via multiplexers to the DAQ system for digitisation during the 99.4ms gap between the bunch trains of the European XFEL. The AGIPD 1.0 ASIC features 64×64 pixels with a pixel area of 200×200 µm2. It is bump-bonded to a 500 µm thick silicon sensor. The principles of the chip architecture were proven in different experiments and the ASIC characterization was performed with a series of development prototypes. The mechanical concept of the detector system was developed in close contact with the XFEL beamline scientists to ensure a seamless integration into the beamline setup and is currently being manufactured. The first single module system was successfully tested at APS1 the high dynamic range allows imaging of the direct synchrotron beam along with single photon sensitivity and burst imaging of 352 subsequent frames synchronized to the source.

Free-Electron Lasers and Synchrotrons are rapidly increasing in brilliance. This has led a requirement of large dynamic range and high frame rate sensors that is now being fulfilled by the PERCVIAL CMOS imager for direct X-ray detection developed at Rutherford Appleton Laboratory. Utilising a lateral overflow pixel and back-side illumination, PERCIVAL simultaneously achieves low-noise single-photon detection and high full well up to 107 e−, all while maintaining a frame rate of 120Hz. PERCIVAL is currently in test structure stage, and will be produced in 2 Mpixel and 13 Mpixel “waferscale” variants in 2015.

The PERCIVAL soft-X-ray (250 eV 1 keV) image detector project is a collaboration between DESY, STFC, Elettra Sincrotrone Trieste and Diamond Light Source. The objective of the project is to develop a back-thinned CMOS detector which outperforms present soft-X ray image detector technology, in terms of sensor size, noise, dynamic range and frame rate. The size of this 13M pixel imager associated with its 120 frames per second frame rate impose very challenging requirements to the Data Acquisition Backend of the system. A DAQ backend system architecture, using a commercial deep-buffer switch to rearrange image data streams coming from different regions of the sensor via several 10Gbps Ethernet links has been proposed to reassemble image frames. Real-time data processing is to be performed on multiple, parallel commodity compute nodes. This contribution to the conference reports on benchmarking tests performed as a feasibility study, and presents the resulting recommendations for the system architecture of the PERCIVAL detector DAQ backend. The feasibility study covered three key issues: Reliably moving data in UDP packets from multiple 10Gbps Ethernet links from the DAQ front-end electronics to commodity compute nodes; Real-time processing on the compute nodes; and finally streaming data to a central parallel storage system.

First results obtained with prototypes of a new type of beam profile monitor based on semi-transparent CVD-diamond are presented. The devices consists of a few micrometer thin membrane on a Si-substrate. Ti/Al-pixel are generated lithographically on the membrane while the signal wires are deposited on a dielectric in order to minimise signal pickup. Synchrotron radiation tests at 8 keV showed good signal homogeneity, spatial resolution and linearity for low resistivity diamond membranes. Considerable difficulties were encountered in the test of a detector grade diamond membrane. They are most likely related to enhanced surface conductivity and capacitive effects.

The conventional method to measure small induced changes in integrated intensity utilizes a zero-dimensional detector, which greatly limits the data collection speed. This paper shows that the use of an area detector in combination with an X-ray chopper decreases the data collection time significantly. A monochromatic diffraction setup using a charge-coupled device (CCD) detector coupled to an X-ray image intensifier was constructed and tested. The setup proved to be sufficiently stable to measure changes in integrated intensity well below 0.1%. Subsequently, a data set of a piezoelectric KD2PO4crystal in an external electric field was collected. The data were merged to yield 77 unique reflections. The induced structural changes were determined by a least-squares refinement. The results agree very well with experiments in which a zero-dimensional detector was used. The major improvement is the decrease in data collection time by one order of magnitude, without any degradation of the data quality, offering new possibilities for this type of perturbation study.

An accurate knowledge of zeolite structure is required for understanding their selective sorption capacities and their catalytic properties. In particular, the positions of the exchangeable cations and their interactions with the framework are essential. The present study deals with the accurate crystal structure determination of a fully exchanged and fully dehydrated CaA zeolite (Ca48Al96Si96O384, Fm\bar 3c, a = 24.47 Å) using single-crystal high-resolution synchrotron X-ray diffraction [(sin θ/λ)max = 1.4 Å−1]. It is shown that cation exchange severely distorts the skeleton, especially around the O2 atom. The high-resolution synchrotron data reveal that this latter O atom is disordered and lies out of the mirror plane it occupies in other A-type zeolites. This feature is related to that observed for Ca2+ cations.

In this paper the electric-field induced distortions in the unit cell of both KDP $({\mathrm{KH}}_{2}{\mathrm{PO}}_{4})$ and DKDP $({\mathrm{KD}}_{2}{\mathrm{PO}}_{4})$ as function of temperature are measured using x-ray diffraction. For both compounds the ${d}_{36}$ shows a Curie-Weiss behavior, with constants $3.61(3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}\mathrm{K}\mathrm{C}/\mathrm{N}$ for KDP and $4.4(2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}\mathrm{K}\mathrm{C}/\mathrm{N}$ for DKDP. For DKDP we measured the electric-field induced change in integrated intensity of a number of reflections at room temperature. These changes were submitted to a refinement where the shifts of the atoms and the ordering of the deuteriums were determined. In the presence of an electric field of $2.7\ifmmode\times\else\texttimes\fi{}{10}^{6}\mathrm{V}/\mathrm{m}$ parallel to the c axis, the P atom is displaced by $27(3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}\AA{}$ along the c axis, and a redistribution of the deuteron over the two formerly equivalent sites takes place. The site towards which the P atom moves is decreased in occupancy in favor of the other by an amount of $0.8(2)%.$ The distortion of the oxygen framework is marginal. These results agree very well with experiments where the phase transition was induced by cooling below ${T}_{C}.$ On the basis of the structural changes, the calculated electric-field induced polarization was $0.18(4)\ensuremath{\mu}{\mathrm{C}/\mathrm{c}\mathrm{m}}^{2},$ consistent with other experiments. Based on our findings we discuss the sequence of the main structural changes involved in the phase transition.

The absolute configuration of AlPO4-5 has been determined from single crystal X-ray diffraction data. The intensities of Friedel related reflections were measured at room temperature from a microcrystal (maximum size ∼50 μm) using synchrotron radiation (λ=1.46 A) and at 100 K from a larger crystal (∼250 μm) using radiation from a sealed Cu tube (λ=1.5418 A). Both data sets indicate the same absolute configuration. The Al(O)P vector, parallel to the polar channel axis, points along the main growth direction. Perpendicular to the main growth direction, the crystal is terminated by an Al(O)P plane with the Al atoms at the surface. The crystal structure of AlPO4-5, a=b=13.718(1) A, c=8.4526(5) A, and γ=120.00°, is described as consisting of three types of microdomains, each exhibiting P6 symmetry. The domains are related by two sets of glide planes. The average structure has P6cc symmetry. All observed angles and distances are within acceptable limits: P–O=1.50–1.57 A, Al–O=1.69–1.76 A, O–P–O=104–119°, O–Al–O=99–124° and Al–O–P=137–154°. The observed (weak) diffuse scattering might be caused, besides, the disorder of the template molecules, by incoherent scattering of domain walls, which exhibit geometries slightly different from each of the three domains.

A new diffraction technique based on a wide-energy-bandpass X-ray beam in connection with lock-in detection for diffraction studies of crystals subjected to external perturbations has been developed. The broad-energy-bandpass beam is obtained by combining a wiggler or bending-magnet source with a curved Si monochromator in Laue geometry. This new technique has been applied in diffraction experiments on single crystals in external electric fields. Both the speed and accuracy of the measurements are increased by more than two orders of magnitude compared with conventional methods.

Results obtained from numerical calculations of and experimental studies on the pulse height distribution inherent in ionizing radiation gallium arsenide sensors as a function of the design features of the devices and electrophysical characteristics of the detector material are presented. It is shown that the pulse height distribution is defined by the distribution pattern of the nonequilibrium charge carrier lifetime and by the electric field profile in the bulk of the sensor. Investigations on the detector sensitivity to X-ray energies in the range between 40 and 150 keV were performed. The sensor polarization was found to produce only a marginal effect compensated by an increase in the bias voltage. Prototype pixel sensors measuring 256 × 256 and 512 × 768 pixels with a 55 μm pitch and a 500 μm thick sensitive layer were produced. The dependence of the photocurrent and count rate on the X-ray radiation intensity and bias voltage applied to the sensor was examined. In the 40–80 keV energy range, the maximum count rate amounted to 800 kHz/pixel for a negative sensor bias voltage of 800 V. The sensors are demonstrated to provide spatial resolution varying with the pixel pitch and to enable high-quality X-ray images to be obtained.

High-frame-rate X-ray pixel detectors make it possible to perform time-resolved experiments at synchrotron beamlines, and to make better use of these sources by shortening experiment times. LAMBDA is a photon-counting hybrid pixel detector based on the Medipix3 chip, designed to combine a small pixel size of 55 μm, a large tileable module design, high speed, and compatibility with ``high-Z'' sensors for hard X-ray detection. This technical paper focuses on LAMBDA's high-speed-readout functionality, which allows a frame rate of 2000 frames per second with no deadtime between successive images. This takes advantage of the Medipix3 chip's ``continuous read-write'' function and highly parallelised readout. The readout electronics serialise this data and send it back to a server PC over two 10 Gigabit Ethernet links. The server PC controls the detector and receives, processes and stores the data using software designed for the Tango control system. As a demonstration of high-speed readout of a high-Z sensor, a GaAs LAMBDA detector was used to make a high-speed X-ray video of a computer fan.

Hybrid pixel semiconductor detectors provide high performance through a combination of direct detection, a relatively small pixel size, fast readout and sophisticated signal processing circuitry in each pixel. For X-ray detection above 20 keV, high-Z sensor layers rather than silicon are needed to achieve high quantum efficiency, but many high-Z materials such as GaAs and CdTe often suffer from poor material properties or nonuniformities. Germanium is available in large wafers of extremely high quality, making it an appealing option for high-performance hybrid pixel X-ray detectors, but suitable technologies for finely pixelating and bump-bonding germanium have not previously been available. A finely-pixelated germanium photodiode sensor with a 256 by 256 array of 55 mu m pixels has been produced. The sensor has an n-on-p structure, with 700 mu m thickness. Using a low-temperature indium bump process, this sensor has been bonded to the Medipix3RX photon-counting readout chip. Tests with the LAMBDA readout system have shown that the detector works successfully, with a high bond yield and higher image uniformity than comparable high-Z systems. During cooling, the system is functional around -80 degrees C (with warmer temperatures resulting in excessive leakage current), with -100 degrees C sufficient for good performance.

X-ray Diffraction (XRD) is an outstanding tool for structural analyses at the atomic scale, and both the experimental techniques and the theoretical interpretations are well established. X-rays also have the advantage of being highly penetrating, as compared to electrons for instance, allowing for the study of bulk materials, or to study samples in complicated environments. The high photon fluxes available at third generation synchrotron sources make it possible to collect full diffraction patterns in relatively short times, and thus to follow time varying processes in-situ. In the first part of this chapter we briefly discuss the advantages and disadvantages of X-rays as compared to other probes like electrons or neutrons. In the second part as an example in-situ surface X-ray diffraction studies of growing films using pulsed laser deposition (PLD) will be presented. The hetero-epitaxial growth process, especially of the first mono-layers can only be understood by in-situ diffraction studies in the PLD chamber under deposition conditions. Also high energy diffraction of buried interfaces will be discussed briefly. The final part of this chapter will present the possibilities for in-situ diffraction studies at the upcoming Free-Electron Laser sources, with fully coherent beams and sufficient intensities to collect full diffraction patterns with single 100 femto-second pulses. The characteristics of the Free-Electron-Lasers and various planned experiments will be presented.

A high-resolution structural study of magnesium formate dihydrate was performed using high-energy synchrotron radiation (0.22 A) and an X-ray image intensifier/CCD (charge-coupled device) detector. The complete data collection was performed in less than 2 h. The data were treated by two different integration programs and the results are compared. The data quality was sufficiently high to produce good-quality electron difference density maps.

A structural analysis of the double-collapsed-phase ${\mathrm{Bi}}_{6+x}{\mathrm{Sr}}_{9\ensuremath{-}x}{\mathrm{Fe}}_{5}{\mathrm{O}}_{26}$ is presented in light of the modulated-phase ${\mathrm{Bi}}_{2.4}{\mathrm{Sr}}_{2.6}{\mathrm{Fe}}_{2}{\mathrm{O}}_{9+\ensuremath{\delta}}$ previously investigated [Y. Lepage, W. R. McKinnon, J. M. Tarascon, and P. Barboux, Phys. Rev. B 40, 6810 (1989); O. P\'erez, H. Leligny, D. Grebille, J. M. Grene\^{}che, Ph. Labb\'e, D. Groult, and B. Raveau, Phys. Rev. B 55, 1236 (1997)]. The study was carried out on a single crystal, using synchrotron radiation $(\ensuremath{\lambda}=0.326 \AA{})$. The crystal is monoclinic with cell parameters $a=16.491(9) \AA{}$, $b=5.481(3) \AA{}$, $c=30.086(16) \AA{}$, $\ensuremath{\beta}=91.39(2)\ifmmode^\circ\else\textdegree\fi{}$. The real structure of symmetry ${P2}_{1}/n$ appears as a small perturbation of the ideal structure with higher symmetry $B2/m$. The undulating ${(001)}_{m}$ layers of the modulated $(m)$ phase built from one kind of cation (Bi, Sr, or Fe) are replaced by mixed layers. The waving of these layers is less regular than in the modulated phase because interrupted layers are connected. One of the most interesting results relates to the interrupted Bi layers: the isolated blocks composed of two adjacent infinite [010] ribbons, six Bi atoms wide, are similar to the ordered part (condensed zones) of the Bi-2212 modulated phase. The Bi disordered regions (diluted zones) are missing in the double-collapsed phase. An original octahedral coordination is implied for the Bi atoms located near the Fe atoms in the same undulated mixed layer. Disorder phenomena have been observed in a complementary HREM study and appear as localized faults modifying mainly the length of the Bi ribbons.

Composite samples are produced by casting copper around a long, single-fibre inclusion of tungsten. Samples are subsequently wire-drawn to reduce the grain size. Using high energy X-ray diffraction, the spatial distribution of residual lattice strains is mapped, showing large strain gradients between the sample surface and fibre matrix interface in samples with different thermal histories. The large strain gradients are primarily attributed to inhomogeneous deformation caused by the presence of the fibre during drawing. Distinct non-linearities in the strain gradients are attributed to the development of strong radial texture variations, and annealing at 300°C is found to significantly reduce the magnitude of the strain gradients.

The European X-Ray Free Electron Laser (XFEL) will provide ultra short, highly coherent X-ray pulses which will revolutionize scientific experiments in a variety of disciplines spanning physics, chemistry, materials science, and biology.

Hybrid semiconductor pixel detectors are considered of high interest for synchrotron applications like diffraction and imaging experiments. However, at photon energies above 30 keV, high-Z sensor materials have to be used due to the weak absorption of the most commonly used sensor material, for instance silicon wafers with a thickness of a few hundred μm. Besides materials like CdTe and Ge, semi-insulating, chromium compensated SI-GaAs(Cr) proves to be a promising sensor material for applications with X-rays in the mid-energy range up to ~60 keV. In this work, material characterisation of SI-GaAs(Cr) wafers by electrical measurements and synchrotron white beam topography as well as the characterization and application of pixel detector assemblies based on Medipix readout chips bump-bonded to 500 μm thick SI-GaAs(Cr) sensors are presented. The results show a very homogeneous material with high resistivity and good electrical properties of the electrons as well as a very promising imaging performance of the detector assemblies.

A modular system of techniques and software has been developed for the calibration and correction of intensity linearity, uniformity of response, spatial distortion, and image plate decay. With calibration the Molecular DynamicsTM Imaging Plate scanner system has been shown to give comparable results to the MarResearchTM scanner. The ESRF x‐ray image intensifier/charge‐coupled device detectors inherently cause large spatial and uniformity of response distortions, and successful data analysis depends on calibration and correction. Results of synchrotron radiation experiments are presented.

In this paper we present a low noise high dynamic range analog front-end ASIC designed for the Adaptive Gain Integrating Pixel Detector (AGIPD) being developed for the European X-ray Free Electron Laser (XFEL) facility. The ASIC has 64 × 64 pixels with a pixel size of 200 × 200 μm2, and is bump bonded to a silicon sensor for X-ray imaging. Each pixel includes an adaptive gain charge integrating amplifier (AGCIA) and 352 analog storage cells. The gain of the AGCIA dynamically adapts to the number of photons arriving at the sensor in order to achieve a single photon resolution and a dynamic range of more than 104 12 keV photons. The XFEL bunch trains consist of up to 2700 bunches separated by 220 ns (600 us in total) followed by an idle time of 99.4 ms. The AGCIA operates in a 220 ns repeating cycle by storing images and the gain information into the pixel memory during the pulse train. The stored images are read out during the breaks of the bunch trains. Several prototypes are designed and fabricated in IBM 130 nm CMOS technology. The measurements showed an input equivalent noise charge (ENC) lower than 300 e- and a dynamic range of 7000 photons.