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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.

Journal of synchrotron radiation 28(1), 131 - 145 (2021). doi:10.1107/S1600577520013958, In this paper the back-side-illuminated Percival 2-Megapixel (P2M) detector is presented, along with its characterization by means of optical and X-ray photons. For the first time, the response of the system to soft X-rays (250 eV to 1 keV) is presented. The main performance parameters of the first detector are measured, assessing the capabilities in terms of noise, dynamic range and single-photon discrimination capability. Present limitations and coming improvements are discussed., Published by Wiley-Blackwell, [S.l.]

An alternative to the currently existing elemental basis for creating dynamic random-access memory and flash memory is memristor structures, i.e., two-electrode systems, whose operation is based on the resistance switching effect. In this paper, the results of studying the specific features of the production of memristor structures on the basis of copper sulfide as a promising material providing high-efficiency performance of the structures are reported. The process of copper sulfurization is considered. In this process, the surface region of the copper layer is transformed into sulfide, and the remaining part of the layer is used as the active electrode for the later formed memristor structure. It is shown that, as the concentrations of the initial chemical reagents is increased, the surface roughness of the sulfide layer significantly increases. The sulfide growth rate at optimal initial concentrations of the chemical reagents is ~30 nm/min. In studies of memristor structures, it is established that, as the copper sulfide thickness is increased, the ratio between the resistances in the low- and high-resistance states increases from 11.2 to 12.5. In the memristor structures formed in the study, the time of switching from the high- to low-resistance state is about 1.3 μs, whereas the time of switching from the low- to high-resistance state is 0.9 μs.

In this paper, the study of the dynamic pyroelectric effect under different powers of modulated heat flux in deuterated triglycine sulfate (DTGS) near the Curie point is presented. It was f...

For a typical low complexity video sequence, the weight of each P-frame in the stream is approximately three times smaller than the I-frame weight. However, taking into account the number of P-frames in the group, they make the main contribution to the total video data amount. Therefore, the possibility of upgrading coding methods for P-frames is considered on preliminary blocks' type identification with the subsequent formation of block code structures. As the correlation coefficient between adjacent frames increases, the compression ratio of the differential-represented frame's binary mask increases. The compression ratio of the differential-represented frame's binary mask varies from 3 to 21 depending on the correlation coefficient between adjacent frames. Estimation of the bit representation's information content of the differential-represented frame's binary mask on the basis of accounting for the nonequilibrium of the bases of the lengths of the binary series does not require an increase in the complexity of the software-hardware implementation. Due to the double-alphabetic power code, the differential-represented frame's binary mask is relative to the single-alphabet code will decrease by 17%. The most preferable method for constructing the compact representation technology of the binary masks of frames represented in a differential form is the approach. This is based on the identification and description of the lengths of one-dimensional binary series. A binary series is a consecutive binary elements sequence with the same value. In this case, sequences of identical binary elements are replaced by their lengths. And since the elements of the binary masks of the frames represented in the differential form take only two possible values 0 or 1, it is suggested to form the lengths of the binary series without indicating their level.

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 work, a process solution for the formation of an array of piezo- and pyroelectric structures with the use of a matrix of nanoprofiled silica is demonstrated. It is proposed to use plasma etching through a hard mask of porous anodic alumina for the formation of the matrix. Nanoparticles of a ferroelectric copolymer of vinylidene fluoride with trifluoroethylene are formed in the pores of the matrix. The results of measurements of the piezoelectric and pyroelectric responses of this structure are presented.

The frequency dependence of real (e′) and imaginary (e″) components of the complex dielectric permittivity has been determined for tin-thiohypodiphosphate Sn2P2S6 films in the temperature region from 150 to 400 K. There are two dielectric relaxation regions in the frequency range between 10−1 and 107 Hz. The high-frequency dielectric dispersion region at 103–107 Hz exhibits Debye type behaviour due to a semiconductor-metal interface barrier similar to a Schottky barrier. At low frequencies from 10−1 to 103 Hz, dielectric response is nearly a “flat loss” at least in the low-temperature region. At elevated temperature, the flat dispersion region disappears and a strong linear decrease of e″ (ω) is observed because of the dc conductivity.

In this paper we demonstrate a technological route for the formation of an array of memristor structures using a self-assembly matrix of porous anodic aluminum oxide. We propose using a porous alumina matrix as a solid mask to develop pores in the dense silicon oxide layer below the mask, in which a material characterized by the possibility of resistive switching is formed. The merit of this mask should include reproducibility and the high-precision control of geometric parameters of the pores. The current-voltage characteristics of a memristor structure based on solid electrolyte Cu2S are determined.

Improving the ways of magnetic structure investigation with the lowest possible resolution is important in the study and practical implementation of fundamental magnetism. Here we discuss one of the most modern magneto-optical method of domain structure (DS) imaging, scanning near-field magneto-optical microscopy (SNMOM), and propose the new technology based on focused ion beam (FIB) treatment to produce aperture cantilevers with carbon hollow pyramid tip (ACCT). Estimated ACCT light transmission coefficients show better results compare to commonly used aperture silicon cantilevers. By measuring the polarization characteristics of aperture with diameter from 83 to 263 nm, we illustrate the possibility of ACCT to maintain a liner polarization of transmitted light. Testing of ACCT in atomic-force and SNMOM modes shows that ACCT are the effective tool in near-field imaging. Features of morphology and DS of Bi-substituted iron garnet (Bi: IG) films synthesized and used as the test objects, including DS peculiarities of 100 nm-size, is revealed.

The preparation method of magnetoelectric multilayered ceramic heterostructures was suggested, and series of the rectangular and disk shape samples were produced on the base of this method. The maximum value of a magnetoelectric voltage coefficient αE = 35 V/(cm × Oe) was observed for the eleven-layered rectangular specimen at the electromechanical resonance frequency fr = 144 kHz, НDC = 84 Oe, and НAC = 2.5 Oe. The sensitivity to static magnetic fields is equal to 3.5 × 10−2 Oe, and the alternating field sensitivity is equal to 8 × 10−3 Oe.

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.

Atomic force microscopy is one of the most popular method of investigation of samples surface at nanoscale. The most common problem of atomic force microscopy (AFM) is the obtaining real geometrical parameters during the studing of nano scale objects. Actually obtained AFM image is a “convolution” of images of the cantilever tip and the investigated object. This effect, called “image convolution” limits the resolution of AFM. Thus one of the most important task for researchers is to minimize this effect by reducing tip size. Classic microelectronic batch process allows to create hundreds AFM cantilevers simultaneously with tip curvature radius from 10 nm and more. Individual process methods (for example focused ion beam) allows to reduce tip radius down to several nanometers but for one cantilever per time only. Authors developed technology to reduce probes curvature radius by using defocused ion beam. The method could be used for both individual and batch processes. Basic principles of technology and results of its implementation are showed in this paper.

The work is devoted to the study of the formation of zinc oxide films in four different ways: by magnetron sputtering, deposition from the gas phase, by dip-coating, and by atomic layer deposition. The effect of alloying additives of subsequent thermal annealing on the morphology and electrical conductivity of the films obtained is reflected. It has been established that the smallest roughness of films is obtained when films are deposited by atomic layer deposition.

In this work experimental research results of silicon deep plasma etching features during 3D-TSV structure producing in inductively coupled plasma are presented. Silicon etching operational parameters influence (inductor RF power, working gas consumption) on process technological characteristics (Si etching rate, selectivity and etching profile) is investigated. Wherein passivation stage’s operational parameters were not changed and were constant. It is shown that microroughness in the form of microneedles and column structures can be formed on the bottom of formed structures at low RF power values; full stop of Si etching process can be also possible. It has been revealed that during polymerization stage fluorocarbon film’s deposition rate increase is observed on structure’s inclined surface in comparison with film’s deposition rate on vertical surfaces. At the same time fluorocarbon film’s deposition rate on the bottom of trench is higher than in inclined surface of the structure. Silicon surface after deep plasma etching process is studied. Fluorocarbon film’s adhesion to silicon and silicon oxide ability is researched. It is demonstrated that adhesion on test samples has small values or missing.

2019 26th IEEE International Conference on Electronics, Circuits and Systems (ICECS), Genoa, Italy, 27 Nov 2019 - 29 Nov 2019; ... IEEE International Symposium on Circuits and Systems proceedings 51, 50 (2019). doi:10.1109/ICECS46596.2019.8964996, High brilliance synchrotrons and Free Electron Lasers (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 describe the P2M CMOS sensor, designed for soft X-ray detection at such facilities. We refer to previous work on test devices demonstrating a noise of 5Me- and quantum efficiency of >80% at 400eV (and with good sensitivity even below this value). Initial test results on the first Front Side Illuminated (FSI) 2 Megapixel device are also presented, and an outline of future work is described., Published by Inst. of Electr. and Electronics Engineers, New York, N.Y.

Certifying a transport airplane for the flights under icing conditions requires calculations aimed at definition of the dimensions and shapes of the ice formed on the airplane surfaces. Up to date, software developed in Russia for simulation of ice accretion and authorized by Russian certifying supervisory authority, is absent. The paper describes methodology IceVision recently developed in Russia for calculations of ice accretion on airplane surfaces. This methodology is implemented in CFD software FlowVision used by numerous companies and universities in Russia and abroad. The methodology differs from known approaches to simulation of ice accretion. In particular, changing the ice shape is calculated with use of technology VOF. This technology assumes calculations of continuous ice growth accompanied by local rebuilding the computational mesh. The implemented mathematical model provides capability to simulate formation of rime (dry) and glaze (wet) ice. Numerical solutions of validation test problems performed using methodology IceVision are demonstrated.Certifying a transport airplane for the flights under icing conditions requires calculations aimed at definition of the dimensions and shapes of the ice formed on the airplane surfaces. Up to date, software developed in Russia for simulation of ice accretion and authorized by Russian certifying supervisory authority, is absent. The paper describes methodology IceVision recently developed in Russia for calculations of ice accretion on airplane surfaces. This methodology is implemented in CFD software FlowVision used by numerous companies and universities in Russia and abroad. The methodology differs from known approaches to simulation of ice accretion. In particular, changing the ice shape is calculated with use of technology VOF. This technology assumes calculations of continuous ice growth accompanied by local rebuilding the computational mesh. The implemented mathematical model provides capability to simulate formation of rime (dry) and glaze (wet) ice. Numerical solutions of validation test problems pe...

In this paper, we are presenting the Percival detector, a monolithic CMOS Imager for detection of soft x-rays in Synchrotron Rings and Free Electron Lasers. The imager consists in a 2D array of many (2M) small (27um pitch) pixels, without dead or blind zones in the imaging area. The imager achieves low noise and high dynamic range by means of an adaptive-gain in-pixel circuitry, that has been validated on prototypes. The imager features on-chip Analogue-to-Digital conversion to 12+1 bits, and has a readout speed which is compatible with most of Free Electron Laser Facilities. For direct detection of low-energy x-rays, the imager is back-illuminated and post-processed to achieve 100% fill factor.

A study of functioning of the magneto-optical method as part of magnetic force microscopy (MFM) is presented. Major errors in measuring the samples with MFM are discussed. The magneto-optical method enables us to perform a preliminary verification of a sample magnetic structure, providing minimal errors being specific for MFM. Design options for operation of the magneto-optical method as a part of MFM are proposed.

Scanning probe microscopy (SPM) is a widely used method for the different kind of objects investigation. It allows to obtain information about the surface topography including its mechanical and electromagnetic characteristics at nano scale. SPM also could be used for manipulation of nanoobjects. The most popular and widely used SPM methods are atomic force (AFM) and magnetic force microscopy (MFM). Both of them based on measuring interaction between sample and cantilever (probe). Type of cantilever its curvature radius, coating, resonant frequency, hardness and other parameters significantly influence on the SPM images. Scientist constantly improving process of probes producing to fit the current demands. It is important to keep in mind that collected AFM data could contain not only direct information about the sample but also it might be a convolution of the sample and cantilever in case then the tip size comparable with the studied object. Convolution effect limits the AFM resolution [1]. Thus one of the most important task for researchers is to minimize this effect by reducing tip size both for AFM and MFM methods.

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.

In this work, pyroelectric properties of composite films on the basis of poly(vinylidene fluoride-trifluoroethylene) copolymer with a various level of ferroelectric ceramics inclusions of barium lead zirconate titanate solid solution were investigated by the dynamic method. The composite films were prepared by the solvent cast method. The unusual spike-like dynamic response with a quasi-stationary component was observed. It is supposed that composite films may be effectively used for pyroelectric applications.

We demonstrate application of integration scanning near-field optical microscopy and atomic force microscopy for investigation of magnetic and ferroelectric materials. This integration is made by using innovative optical and micromechanical components. Optical measuring head with cantilever holder was designed for both near-field optical microscopy and atomic force microscopy modes. Hollow pyramid cantilever with aperture at the tip was designed for registration both optical signal and tip=sample interaction forces. Cantilever aperture was made by ion beam at the center of pyramid. Same probe was used for both topography and domain structure visualization of magnetic samples. Bi: YIG-thin films topography and domain structure were investigated by this method as well as by conventional magnetic force microscopy (MFM). In integrated method of scanning nearfield polarization optical microscopy and atomic force microscopy samples were excited through cantilever aperture by tightly focused linearly polarized laser beam. Magneto-optical effect of the rotation of polarization plane of transmitted light depends on domain orientation. Visualization of magnetic domains was performed by detecting cross polarized component of transmitted light. Near field map of magnetic domains provides direct information of the magnetic moment of domains unlike MFM image which provides distribution of magnetic force gradient. Moreover, non-magnetic hollow-pyramid probe prevents sample from possible disturbances by internal magnetic moment of the MFM probe. Comparison of results obtained by near field polarization microscopy and conventional MFM was performed. We demonstrate possibility of investigation of topography and domain structure ferroelectric materials by integration method of near-field optical microscopy and atomic force microscopy.

In this paper the different digital phase-locked loop based structures and techniques to implement carrier recovery and data demodulation of high rate M-ary PSK signals are analysed. Costas and Square Loops are a main in the consideration. Methods to cope with inherent problems related to noise performance, settling time and lock range are discussed and corresponding algorithms are proposed. The Questions of handling Doppler-shifted carriers are also in subject.

Magneto-optical microscopy is a well-known and widely used method of magnetic domain structure investigation. Spatial resolution is limited by diffraction limit of the light and practically not exceed 0.5μm. Possibility to overcome diffraction limit by combination of magneto-optical microscopy and magnetic-force microscopy was showed earlier [1]. Aperture cantilever was used to light up the sample in near-field mode. In this paper, authors review most popular technology for aperture cantilever production with its advantages and disadvantages. Authors propose new technology based on focused ion beam treatment for creation aperture cantilevers with advanced parameters such as small aperture size and light throughput. Bi-substituted yttrium iron garnet (Bi: YIG) thin films with high magneto-optical activity and different period of domain structure were used as test objects. High resolution images of both morphology and domain structure obtained with new advanced aperture cantilevers are shown.

In this work, we have formed CuO memristive array embedded into porous SiO2 layer. Such an approach would create synaptic system on silicon substrate using standard integrated electronics operations. It also provides control over the geometric parameters of artificial synapses, which determines their synaptic weights. The results of synaptic behavior have shown that the value of synaptic weights and currents are dependent on the thickness of the CuO filled SiO2 porous layer.

The film structures on the base of soft and crystalline ferroelectrics (poly(vinylidene fluoride - trifluoroethylene) copolymer and deuterated triglycine sulfate) were produced. The volume content of the DTGS microcrystal particles embedded in the polymer matrix of the composite films was up to 10%. It was found crystalline phase changes in the polymer matrix at the DTGS inclusions presence. The DTGS crystal particles increased dielectric permittivity and electrical conductivity of the composite films. The temperature dependences of the dielectric permittivity indicated increasing the phase transition temperature of polymer matrix at the DTGS inclusions growth.

In the present work, the comparative study of the electric response of Sn2P2S6 films to the visible light action was carried out without and under external electric field. The light flux modulated by a chopper induces the integral response comprising time-dependent photoelectric and photovoltaic components. It was shown that spontaneous polarization influences the electric response characteristics.

The peak brilliance reached by today's Free-Electron Laser and Synchrotron light sources requires photon detectors matching their output intensity and other characteristics in order to fully realiz ...

The results of a study into the effect of cantilever structural parameters on the sensitivity of magnetic force microscopy (MFM) have been presented. It has been shown that it is necessary to use cantilevers with an optimal thickness of the magnetic coating and hardness of the beam lying in the range from 0.1 to 1.0 N/m in order to ensure the maximum sensitivity of the method. The use of these cantilevers makes it possible to register locally arranged single-domain iron particles ∼50 nm in size.

This paper presents the results of comparative analysis of the electrical and mechanical characteristics of the tungsten and tungsten alloyed with rhenium films deposited on silicon, from the point of view of their use as interconnects in silicon ICs. W and W (Re-5%) alloyed with rhenium films were made by magnetron deposition. Sheet resistivity for W and W (Re- 5%) was 13 and 27 μOhm·cm respectively. Elemental composition the formed films was examined by Auger spectroscopy. To investigate the electromigration resistance of the conductors a methodology based on the accelerated electromigration testing at constant temperature was used. A comparative analysis of the mechanical stresses carried out in the W and W(Re - 5%) films. For this purpose was applied non-destructive method for optical laser scanning. At the same time, these films explored their ability of adhesion to silicon and silicon oxide. It is shown that the pull force of the W(Re - 5%) films was ~1500 G/mm 2 , of the W films ~ 700 G/mm 2