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In this paper, X-ray induced color-tunable long afterglow luminescent material Ca 9-x Tb(PO 4) 7 :xMn2+ was synthesized by high-temperature solid state reaction. The effects of Mn2+ doping concentration on the properties of the samples were studied by XRD, SEM, fluorescence and afterglow spectra. The results showed that there was a very efficient energy transfer between Tb 3+ and Mn 2+ under X-ray excitation, with a transfer efficiency of up to 94.6%, which also contributed to the tunable green-red emission. With the increase of Mn2+ concentration, the green afterglow emissions of Tb3+ mainly at 546.9 nm gradually decreased and even disappeared, while the red afterglow emissions of Mn2+ at 647.3 nm gradually increases due to excellent energy transfer. When the doping concentration of Mn2+ was 0.07, the red afterglow emissions were the strongest. Furthermore, even at low-dose radiation (3 mGy), the sample still possessed excellent afterglow performance, which can persist for more than 5 h. In addition, the samples also showed excellent photostimulated luminescence properties, which can be persist for many cycles by the irradiation of 980 nm laser. The thermoluminescence results revealed that the doping Mn2+ ions can not only enhance the trap concentrations obviously but also created new deep traps with trap depth of 0.864 eV, which thus resulted in better long afterglow luminescence and photostimulated luminescence properties of Ca 9 Tb(PO 4) 7 :Mn2+. [ABSTRACT FROM AUTHOR]

• A soft topological insulator system with imperfect interfaces is modeled. • Tunable phase transitions through finite deformation and adjusting imperfect interfaces' stiffness are studied. • Stiffness of soft imperfect interfaces under finite deformations is given. • Enhancing the stiffness of imperfect interfaces transfers the system from a resonance type to a dispersion type. Acoustic metamaterials, especially the topological insulators, have garnered substantial research attention due to their unique wave properties. Recent research emphasizes the crucial role of imperfect interfaces in accurately simulating and understanding wave propagation within these metamaterials. This paper studies the mechanical properties of soft imperfect interfaces and derives the effects of finite deformations on their stiffness. We present a comprehensive model of a soft Rayleigh beam system that incorporates these interfaces, allowing for the observation of the topological phase transition by altering the distance between them. Our investigation into the impacts of finite deformations and interface stiffness adjustment reveals that longitudinal waves' phase transition points are mainly influenced by interface stiffness. In contrast, transverse waves are predominantly affected by finite deformations. The decisive parameters driving these phenomena are also identified theoretically. The transmission studies of supercells further confirm the presence of topologically protected interface modes and their extensive tunability. Overall, this study offers a novel methodology and framework for managing topological phase transition in composite and soft topological insulator systems. This paper models a soft topological insulator system that integrates the Rayleigh beams with imperfect interfaces. Several methods are utilized to calculate the band structure. The topological phase diagrams are used to investigate the phase transition process. Finally, tunable topologically protected interface modes are studied. [Display omitted] [ABSTRACT FROM AUTHOR]

Solar flares, along with other sun-originated events such as Coronal Mass Ejections, fast solar wind streams, and solar energetic particles are among the most relevant events in Space Weather. Moreover, solar flares are the most energetic processes that occur in our solar system. The in-depth study of their occurrence statistics, both over extended periods or during individual solar cycles, allows us to improve and constrain the basic physical models of their origin. Increasing the number of detected events, especially those of lower intensity, and the number of physical parameters that describe the detected flares is, therefore, a mandatory goal. In this paper, we present a computationally efficient algorithm for the detection of solar flares in the soft-X solar flux provided by the GOES (NASA/NOAA) satellite constellation. Our code produces a new flare catalogue increasing the number of events with respect to the official GOES list. In addition to increasing the number of identified events, the catalogue contains information such as: an estimate of the total energy released, start and end time of the event, possible overlap with other events, background level of the GOES X-ray emission close to the revealed event. After a detailed description of the detection algorithm, we carry out a preliminary analysis of the flares reported in our catalogue and compare our results with the official list of GOES for the period from 1998 to 2020. [ABSTRACT FROM AUTHOR]

In this paper, we propose a novel soft origami tripod structure and mechanism capable of multimodal motions based on electrohydraulic actuators. The tripod structure consists of top and bottom plates connected by three origami legs in parallel. The three electrohydraulic actuators are located at the connecting points between the bottom plate and legs. The actuators are independently swelled by the applied voltage and utilized for extending the soft legs from unfolding. A high degree of freedom (DOF) of the tripod is realized by applying the classic origami pattern waterbomb to the legs, which serve as a spherical joint. The soft tripod has linear and tilting motions while the legs are stretched by independently operated actuators. Basically, the three extended legs achieve linear movement of the top plate. When only one leg is straightened, the other legs become asymmetrical and cause the tripod to tilt. The structure exhibits a linear strain of 122.15% and a tilting angle of 22.25°. In addition, we predict the trajectory of the tripod structure via kinematic modeling and analyze the results based on validation. As a result, the soft origami tripod using electrohydraulic actuators is scalable and controllable with the advantages of multimodal motion and light structure. [Display omitted] • Soft origami tripod had multimodal motions based on electrohydraulic actuators. • Actuators simultaneously utilized electrostatic force and hydraulic pressure. • Tripod structure comprised three origami legs connecting top and bottom plates. • Each leg was self-unfolding by actuator, which could control position of top plate. • Tripod exhibited a linear strain of 122.15% and tilting angle of 22.25°. [ABSTRACT FROM AUTHOR]

Abstract The interlayer plays a crucial role in improving the properties of many extremely important magnetic materials and devices by regulating the magnetic exchange coupling, while it is still not fully understood in a quantitative way. The main obstacle is that there is still no effective way to characterize quantitatively the ferromagnetic exchange coupling (FEC) strength after inserting the interlayer. In this paper, a rationally designed hard/interlayer/soft layered film is used to study the interlayer effects. It is demonstrated that the magnetic properties of nanocomposite magnets can be effectively enhanced through the modification of interface. Here a new concept, using the nucleation field H ns of soft phase as a "detector" to directly and quantitatively characterize/measure the FEC strength across interface and interlayer, is put forward. It is applied to address the dependence of FEC strength on thickness of nonmagnetic Cr and rare earth-rich phase interlayers. The detailed, distinguishing and typical decay behavior and length of FEC strength for these interlayers are successfully resolved for the first time. The new conception and experimental results get also strongly supported by the theoretical calculation. The nature or mechanism of exchange coupling between ferromagnetic grains or layers after adding the nonmagnetic interlayer is identified by using the hard/interlayer/soft layered film as a model system. Our results demonstrate the validity for characterizing/measuring quantitatively the FEC strength across different interlayer materials via strategy established in this work. It opens up new perspectives to gain insight into the interlayer property, and mechanism comprehension and high-performance design for magnetic materials and devices, such as permanent magnets, high-density magnetic recording media, advanced spin-orbit torque devices, etc. Highlights • The interface layer (interlayer) plays a crucial role in improving the properties of many important magnetic materials and devices by regulating the ferromagnetic exchange coupling (FEC), while it is still not fully understood. The main obstacle is that there is no effective way to quantitatively characterize the FEC strength across the interlayer. • In this paper, a new conception, using the nucleation field Hns of soft phase in a rationally designed hard/interlayer/soft layered film to directly characterize/measure the FEC strength across the interlayer(or interface), is put forward. • It is applied to address the dependence of FEC strength on thickness of nonmagnetic Cr and rare earth-rich phase interlayers. The detailed, distinguishing and typical decay behavior and length of FEC strength are successfully resolved. The new conception and experimental results get strongly supported by theoretical calculation. • The nature or mechanism of exchange coupling between ferromagnetic grains or layers after adding the nonmagnetic interlayer is also identified by using the hard/interlayer/soft layered film as a model system. • Our results open up new perspectives to gain insight into the interlayer property, and mechanism comprehension and high-performance design for magnetic materials and devices, such as permanent magnets, magnetic recording media, advanced spin-orbit torque devices, etc. [ABSTRACT FROM AUTHOR]

EUV light optics are either reflective or diffractive due to the substantial absorption characteristics by almost all materials. Despite great successes in manufacturing integrated circuit chips, reflective EUV optics are still unfriendly to small-to-medium enterprise (SME) because of the enormous costs. Recently, diffractive EUV optics has come to the light in hopes to be able to establish manufacturing nanoscale products and inspecting nanoscale structures. Diffractive zone plates with high resolution in EUV wavelengths are urgently needed. This paper reports our latest success in developing 20 nm resolution zone plates for focusing and imaging in the EUV and soft X-ray regions. It firstly discusses the diffraction efficiency of FZPs tailored for 13.5 nm wavelength to decide the essential height of the zone plate. Then, Monte Carlo simulation method was used to figure out the achievable zone plate parameters by high-resolution electron beam lithography (EBL). Finally, this work systematically explored the viability of nanofabricating top-tier 20 nm resolution hydrogen silsesquioxane (HSQ) zone plates with the duty cycle ratio nearing 1:1 and the aspect ratio approaching 13:1 on 50 nm thick Si 3 N 4 membranes. [Display omitted] • 20 nm resolution Fresnel zone plates (FZPs) for EUV were successfully fabricated. • 50-nm thick silicon nitride substrate can improve FZPs' diffraction efficiency. • Hydrogen silsesquioxane (HSQ) FZPs only require a one-step exposure process. • Simulated and experimental results show the 20-nm designed width is the optimal. [ABSTRACT FROM AUTHOR]

The linear depolarization ratio (LDR) is a key parameter used in remote sensing to distinguish particle types. The LDR of the soot fractal model is uneasy to match the measured values. In this paper we used three-dimensional (3D) synchrotron soft X-ray tomography (SXT) for the 3D reconstruction of the toluene-burning soot particles and used discrete dipole approximation to calculate optical properties. The obtained results showed the 3D reconstructed soot particles can efficiently reproduce the measured LDR. The results of this study will encourage us to develop a new morphology model, completely different from the traditional fractal model, for bare soot based on 3D reconstruction. This study is helpful for the understanding and explanation of LDR of bare soot particles. • Soft X-ray tomography is used to construct the three-dimensional soot models. • Three-dimensional (3D) reconstruction is based on voxel recognition of RGB. • 3D reconstructed soot particles can efficiently reproduce the measured LDR. [ABSTRACT FROM AUTHOR]

A microbunching instability (MBI) driven by beam collective effects can deteriorate electron beam quality in advanced x-ray free electron lasers. In this paper, we demonstrate a scheme to suppress microbunching instability by adjusting the compression ratio of two-stage bunch compressor in linear accelerator of the Shanghai soft X-ray Free-Electron Laser User Facility (SXFEL-UF). The calculation of the microbunching instability gain and the mechanism of MBI suppression scheme can be revealed by the theoretical model in this paper. Numerical simulations are presented to verify the analytical results. Furthermore, benefit by the high temporal resolution of transverse deflecting structure (TDS), beam experiments for direct analysis of MBI were carried out at SXFEL-UF. Theoretical calculations as well as simulation and consistent experimental results illustrate that the suppression of microbunching instability can be achieved by increasing the first stage compression ratio of the linac in the SXFEL-UF. The feasible theme provides a promising beam optimization method for future X-FEL facilities. [ABSTRACT FROM AUTHOR]

We developed a 2-mm-thick CdTe double-sided strip detector (CdTe-DSD) with a 250 μ m strip pitch, which has high spatial resolution with a uniform large imaging area of 10 cm 2 and high energy resolution with high detection efficiency in tens to hundreds keV. The detector can be employed in a wide variety of fields for quantitative observations of hard X-ray and soft gamma-ray with spectroscopic imaging, for example, space observation, nuclear medicine, and non-destructive elemental analysis. This detector is thicker than the 0.75-mm-thick one previously developed by a factor of ∼ 2.7, thus providing better detection efficiency for hard X-rays and soft gamma rays. The increased thickness could potentially enhance bias-induced polarization if we do not apply sufficient bias and if we do not operate at a low temperature, but the polarization is not evident in our detector when a high voltage of 500 V is applied to the CdTe diode and the temperature is maintained at − 20 °C during one-day experiments. The "Depth Of Interaction" (DOI) dependence due to the CdTe diode's poor carrier-transport property is also more significant, resulting in much DOI information while complicated detector responses such as charge sharings or low-energy tails that exacerbate the loss in the energy resolution. In this paper, we developed 2-mm-thick CdTe-DSDs, studied their response, and evaluated their energy resolution, spatial resolution, and uniformity. We also constructed a theoretical model to understand the detector response theoretically, resulting in reconstructing the DOI with an accuracy of 100 μ m while estimating the carrier-transport property. First, we evaluated the energy resolution using 22Na, 133Ba, and 57Co reconstructing the DOI effect from the energy correlation on both the anode and cathode sides. We obtained an energy resolution of 4.3 keV (FWHM) at 356 keV. Second, we formulated a theoretical detector-response model that reproduced the experimental data. Using the model, we determined the mobility-lifetime products of carriers μ τ e , h = (4 ± 1) × 1 0 − 3 , (1. 15 ± 0. 05) × 1 0 − 4 [cm 2 /V] with the space charge density of n s p = − 6. 0 × 1 0 10 [1/cm − 3 ] and then reconstructed the DOI with an accuracy of 100 μ m. Finally, we evaluated the spatial resolution and demonstrated to resolve patterns of 250- μ m -width slits with an X-ray test chart. We found no positional variation in the detector response. We realized the detector that has high energy resolution and high 3D spatial resolution with a uniform large imaging area. [ABSTRACT FROM AUTHOR]

A transmission diffraction grating is a useful tool for studying spectra in the soft X-ray and extreme ultraviolet range, created by the radiation of small–sized sources, such as laser produced plasma, vacuum spark, Z-pinch, X-pinch, etc. In almost all such experiments, a distance between the source and the grating is much larger than the size of the source, so the incident wave can be considered plane with sufficient accuracy, the distance from the recording detector to the grating is also much larger than the size of the grating and, therefore, Fraunhofer diffraction takes place here and the presence of a focusing element is not required. The interpretation of the results obtained using such a grating is difficult due to the fact that different diffraction orders overlap in the registered diffraction pattern. Therefore, there is a problem of reconstruction the true spectrum from an experimental diffraction pattern. In this paper, this problem is solved by approximating the function of the radiation intensity recorded on the diffraction pattern by a polynomial. In this case, due to the properties of the transmission diffraction grating, the desired function describing the spectrum being reconstructed is also a polynomial, which can be calculated according to the developed algorithm. Both the direct conversion of the spectrum into the diffraction pattern and the reverse conversion of the diffraction pattern into the spectrum do not change the radius of convergence, since multiplication is carried out by multipliers uniformly bounded from above and below. It follows from this that minor errors in the definition of the function describing the diffraction pattern cannot lead to significant errors in the reconstructed spectrum. [ABSTRACT FROM AUTHOR]

• Image recognition of cracks inside maize seeds based on soft X-rays. • Image enhancement of soft X-ray images was implemented with effective results. • The YOLOv8 model was used and optimized and compared. The current investigation on image recognition and internal crack detection of maize seeds primarily relies on visible light imaging. However, due to the low transmissivity of plant cells, even with image enhancement measures, the clarity of internal cracks in the images and the subsequent feature extraction process can be a trade-off. Soft X-rays possess exceptional penetration capability and offer better safety and convenience compared to hard X-rays, making them highly suitable for visualizing internal structures within plant tissues like maize seeds. In this paper, a non-invasive Imaging Technique for Image Enhancement is proposed, combining wavelet thresholding denoising, image standardization, bilateral filtering, and laplacian sharpening. This method is based on soft X-rays and successfully achieves image recognition of cracks present inside Zhengdan 958 maize seeds using an optimized YOLOv8 model. It effectively addresses challenges related to the limited light transmission of maize seeds, difficulty in crack localization, and algorithm generalization issues. The optimized YOLOv8 model demonstrates an average precision (AP) value that is 3.1% higher than that of the original model. Furthermore, by applying image enhancement, the AP value increases by 1.8%. The proposed method exhibits an average recognition accuracy of 99.66% for intact or broken seeds, an average precision of 99.87%, an average recognition recall of 99.48%, and an average single-frame image detection time of 7.49 ms in the single seed detection experiment. [ABSTRACT FROM AUTHOR]

The Korea fourth-generation storage ring (Korea-4GSR) has a low electron beam emittance of 60 p.m.-rad, and provides a photon beam that is 100 times brighter and 100 times more coherent than the third-generation Pohang Light Source (PLS-II). However, the new source imposes a higher heat load on beamline optics. In particular, the first mirror (M1), which receives the broad-bandwidth white beam will be distorted by the thermal load from X-ray beam and the heat bump will degrade the beam quality. For the thermal analysis of M1, a method is developed to solve the thermal deformation with temperature gradient and absorbed power density. To implement the method in the analysis of heat load effect on M1, a benchmark study was performed on beamline 8A at PLS-II. In this paper, we describe the thermal analysis of M1 in Korea-4GSR after verifying our simulation method in a benchmark study. [ABSTRACT FROM AUTHOR]

Free-electron lasers are capable of producing high-quality radiation in a wide wavelength range and at very high power and brilliance. To reach improved performance especially regarding coherence, bandwidth and wavelength stability, different seeding techniques are often required. However, a successful implementation of seeding typically demands a very high-quality electron beam, in terms of energy distribution and emittance. Techniques like Echo-Enabled Harmonic Generation (EEHG) and High-Brightness SASE (HB-SASE) require, or are significantly enhanced, by a flat distribution of particles in the longitudinal phase space. In this paper we describe how the initially chirped longitudinal phase space in the proposed Soft X-ray Laser (SXL) at the MAX IV laboratory can be tailored by first overcompressing and then de-chirping the electron pulse. We also show that it is possible to retain the properties of the electron bunch and how such an enhanced distribution can drive HB-SASE "seeding", resulting in a significantly reduced bandwidth and a better wavelength stability. [ABSTRACT FROM AUTHOR]

• Interference of transition and Cherenkov radiation fields causes hybrid radiation. • Interference sets the range of the angular distribution with monochromatic X-rays. • Monochromaticity of Cherenkov X-rays is limited by transition radiation influence. • We predict a spectral asymmetry of hybrid radiation in the soft X-ray range. • Considered radiation geometry allows controlling X-rays spectrum and polarization. Vavilov-Cherenkov emission and transition radiation are the well-known phenomena and find a broad application for different scientific communities. In the case of simultaneous generation of both types of radiation, there is a possibility of interference between radiation fields. Thus, the emitted radiation could possess both transition radiation and Vavilov-Cherenkov radiation properties, that is why it should be considered as hybrid radiation. In this paper, we present the results of the theoretical investigation of X-ray hybrid radiation. Using the polarization current approach and the atomic scattering factor formalism to account anomalous dispersion of the complex permittivity we study spectral-angular distributions and polarization states of X-ray hybrid radiation when a charge obliquely falls on a foil. The theoretical results greatly contribute to understanding of X-ray Vavilov-Cherenkov radiation as well as the development of the X-ray narrow band radiation sources based on Vavilov-Cherenkov effect. [ABSTRACT FROM AUTHOR]

This paper investigated the structural evolution of carbon deposition on a Ni/YSZ cermet of a SOFC. The Ni/YSZ cermet was heated in CH 4 /Ar environment with a thermobalance. It was observed that carbon deposition preferentially occurred on Ni particles, and the area on which carbon deposited touched the Ni/YSZ interfaces. Meanwhile, carbon deposition was not found on some of the Ni/YSZ interfaces. The Ni/Zr interfaces had various defects, suggesting that the defect pattern may be an important factor for carbon deposition. XANES spectra showed that structural defects and C–H bonds were present in the nascent carbon deposition. As carbon deposition advanced, a graphite structure developed and C–H bonds diminished. Reactants produced from CH 4 cracking converted to a nascent amorphous carbon at the Ni/YSZ interface, and then contributed to the growth of carbon deposition on Ni surfaces, leading to the deposition of carbon encapsulating the Ni particles. Image 1 • The structural evolution of carbon deposition on Ni/YSZ was analyzed by XANES. • An amorphous structure and C–H bonds were seen in nascent carbon deposition. • As carbon deposition continued, a graphite structure developed. • Various defects on Ni/YSZ interface had different sensitivities to carbon deposition. [ABSTRACT FROM AUTHOR]

• Inter-particle contact evolution of a sheared sand was studied using X-ray μ CT. • The duration and stress-transmission characteristics of inter-particle contacts were studied. • The buckling of stress-transmission contacts was quantified. This paper presents the use of X-ray micro-tomography (X-ray μ CT) and image processing and analysis techniques to investigate the stress transmission and buckling of inter-particle contacts within a granular material. A triaxial testing of a miniature Leighton Buzzard sand (LBS) sample was carried out with full-field in-situ X-ray μ CT scanning. High-spatial-resolution CT images of the sample were acquired at several loading stages of the test. Image processing and analysis techniques were used to quantify the inter-particle contact evolution (contact gain, contact loss and contact movement), fabric, contact duration and buckling of stress-transmission contacts based on the CT images. The results indicated that contact gain and loss, and contact movement played two competing roles in determining the overall fabric evolution of the sample. Contacts with a longer duration were more likely to orient in the major principal stress direction and form a stress-transmission contact network. A gradual decrease in the buckling rate of the stress-transmission contacts was observed outside of the shear band, and a relatively stable buckling rate was observed within the shear band during the shear. The results suggested that jamming occurred outside of the shear band and that unjamming occurred within the shear band. [ABSTRACT FROM AUTHOR]

• Non-radioactive ECD using soft X-rays for electron generation. • Limits of detection in the ppt range for halogenated substances and pesticides. • Similar analytical performance as radioactive ECDs. • Possible replacement of radioactive ECDs in GC and other applications. In this paper, we present a new electron capture detector based on a compact X-ray tube (X-ECD) for electron generation by soft X-ray radiation instead of using a radioactive source. ECDs are commonly used in many laboratories as standard GC detectors since their invention in the 1950s, especially for highly sensitive detection of halogenated substances, pesticides or other environmental pollutants. However, due to unsatisfactory alternatives, many ECDs are still used with radioactive β-emitters, which is difficult and expensive in most applications today due to legal restrictions. The new X-ECD contains a small X-ray tube for generating free electrons by ionizing the carrier gas like in radioactive ECDs. Thus, no additional dopants or special gases are required. The X-ECD has limits of detection in the ppt v range and shows linearity over a wide concentration range. Furthermore, the used X-ray tube shows good long-term stability. So far, we have operated the X-ray tube continuously for about one year without notable degradation. However, in case of future degradation, the X-ECD can still be operated with the same sensitivity by simple adjusting the set point current in constant current mode. This makes calibration robust against possible degradation of the X-ray tube. In combination with a conventional gas chromatograph, the X-ECD is able to detect halogenated hydrocarbons and even low volatile pesticides without any peak distortion such as tailing. Thereby a minimum detectability in the upper fg/µL range for Lindane was reached, which is similar when compared to radioactive ECDs. [ABSTRACT FROM AUTHOR]

In this paper, we have successfully demonstrated that the directional control of the light output of the scintillator can be achieved by mixed-scale microstructures which integrate photonic crystals on the wavelength scale and microlens arrays on the micrometer scale. Compared to the reference sample, the mixed-scale microstructures can enhance the light output of the scintillator by 3.07-fold at the emergence angle of 35°. This enhancement in the light output exhibits both azimuthal angle and wavelength dependence. Our hybrid simulation and experimental characterization explain the physical mechanism behind the enhanced directional light output. This method holds potential for application in radiation detection systems and other light-emitting devices requiring directional light output. • Mixed-scale microstructures control directional light output of scintillators. • Soft X-ray interference lithography can prepare mixed-scale microstructures. • Directional light output is beneficial for the radiation detection system. [ABSTRACT FROM AUTHOR]

This paper reviews our contributions and the development of an instrument for X-ray photoelectron diffraction (XPED) and X-ray holography. XPED and X-ray holography have been extensively applied in materials analysis over the past decades. We made pioneering contributions in this area that fueled the development of the corresponding instrumentation and technology. In this review, we briefly discuss the theory of XPED and X-ray holography instrument, the genesis, and applications. The instruments comprise a high-power soft and hard X-ray source as well as a diffraction aperture; further, they are capable of high-angular-resolution detection and patterning. The applications of these instruments for practical surface analysis are also reviewed for ultrathin insulators, catalysts, and magnetic materials. Finally, possibilities for the differential photoelectron holography (DPH) approach are premiered based on a novel approach. • This paper reviews our contributions and the development of instruments for XPED and X-ray holography over the last decades. • We demonstrated our original laboratory-level XPED instruments from the perspectives of a high-power soft and hard X-ray source, diffraction aperture, and high-angular-resolution detection. • We also demonstrated applications of practical surface analysis for ultrathin insulators, catalysts, and magnetic materials. • We premiered possibilities for differential photoelectron holography (DPH) based on the atomic reconstruction method using typical four-wave numbers. [ABSTRACT FROM AUTHOR]

Abstract: Thin-film solar cells based on compound semiconductors consist of a multilayer structure with various interfaces and contain a multitude of elements and impurities, etc. A rapid progress of these photovoltaic technologies can only be achieved by an insight-driven optimization/development. Hence it is crucial to characterize and understand the relationship between the chemical and electronic properties of these components. This paper reviews some examples of our recent work characterizing compound semiconductor thin films using laboratory- and synchrotron-based electron and soft X-ray spectroscopic characterization methods. It is demonstrated how these different analytical techniques are extraordinarily powerful to reveal the material characteristics from many different perspectives, ultimately resulting in a comprehensive picture of the related electronic and chemical properties. As examples, the paper will discuss the electronic surface structure of chalcopyrite thin-film solar cell absorbers, the chemical structure of the CdS/chalcopyrite interface, present the band alignment at the CdS/kesterite interface, and report on how post-deposition treatments cause chemical interaction/interdiffusion processes in CdTe/CdS thin-film solar cell structures. [Copyright &y& Elsevier]

Abstract We have been developing event-driven SOI Pixel Detectors, named "XRPIX" (X-ray soiPIXel) based on the silicon-on-insulator (SOI) pixel technology, for the future X-ray astronomical satellite with wide band coverage from 0.5 keV to 40 keV. XRPIX has event trigger output function at each pixel to acquire a good time resolution of a few μ s and has Correlated Double Sampling function to reduce electric noises. The good time resolution enables the XRPIX to reduce Non X-ray Background in the high energy band above 10 keV drastically by using anti-coincidence technique with active shield counters surrounding XRPIX. In order to increase the soft X-ray sensitivity, it is necessary to make the dead layer on the X-ray incident surface as thin as possible. Since XRPIX1b, which is a device at the initial stage of development, is a front-illuminated (FI) type of XRPIX, low energy X-ray photons are absorbed in the 8 μ m thick circuit layer, lowering the sensitivity in the soft X-ray band. Therefore, we developed a back-illuminated (BI) device XRPIX2b, and confirmed high detection efficiency down to 2.6 keV, below which the efficiency is affected by the readout noise. In order to further improve the detection efficiency in the soft X-ray band, we developed a back-illuminated device XRPIX3b with lower readout noise. In this work, we irradiated 2–5 keV X-ray beam collimated to 4 μ m ϕ to the sensor layer side of the XRPIX3b at 6 μ m pitch. In this paper, we reported the uniformity of the relative detection efficiency, gain and energy resolution in the subpixel level for the first time. We also confirmed that the variation in the relative detection efficiency at the subpixel level reported by Matsumura (2015) has improved. [ABSTRACT FROM AUTHOR]

Abstract The paper presents experimental results obtained during the first operational phase (called OP1.1) of the Wendelstein 7-X stellarator (W7-X). One of W7-X diagnostics that delivers information about plasma impurities and was commissioned during the OP1.1, is the Pulse Height Analysis (PHA) system which provides soft X-ray spectra of highly ionized impurity species over a very broad energy range with energy resolution not worse than 200 eV and with temporal resolution of 100 ms. The line-of-sight integrated spectra, collected by a Silicon Drift Detector in the energy range between 0.9 and 10 keV, have been analyzed for various experimental conditions and are discussed with respect to results from other diagnostics. In this work, injected impurities (argon and neon) as well as intrinsic impurities (sulphur and chlorine) have been identified. Spectral lines corresponding to heavier impurities have not been observed. [ABSTRACT FROM AUTHOR]

Abstract The overlap between the electron beam and the radiation field is one of the most important characteristics during the free-electron laser (FEL) amplification processes, which will dramatically influence the quality of the FEL radiation. The beam-based alignment (BBA), first proposed in 1980s, has achieved great success in both theoretical and experimental studies on hard X-ray FELs. This paper gives a brief analysis on the undulator misalignment, which has been ignored in the original BBA algorithm. These misalignments, as revealed by the calculation and simulation, tend to have significant impacts on the soft X-ray FELs which are driven by the low energy accelerators. Furthermore, we demonstrate a method that can probably solve this dilemma using a searching algorithm — genetic algorithm. [ABSTRACT FROM AUTHOR]

Spectroptychography is being used to realize a significant improvement in the spatial resolution of x-ray spectromicroscopy, allowing chemical microanalysis at finer spatial scales. The chemical sensitivity of near edge X-ray absorption fine structure (NEXAFS) is familiar to most researchers who use x-ray spectromicroscopy for chemical microanalysis. However, the additional phase information available through ptychography provides additional and tantalizing data, and potentially additional chemical information. This paper explores the chemical information available in phase for a system of silicon dioxide nanospheres. • Soft x-ray spectroptychography provides chemical information through absorption and phase. • Phase spectra reveal chemical information in an indirect manner. • The Kramers–Kronig relation is useful for understanding contrast in ptychography chemical analysis. [ABSTRACT FROM AUTHOR]

In this paper, we give an overview of the nanoscale spectromicroscopy studies performed with the full-field X-ray microscope at the BESSY II electron storage ring. We do not consider spectromicroscopy studies performed with X-ray microscopes operated at other synchrotron sources. Such studies can be found in the literature. To our knowledge, the full-field X-ray microscope at the BESSY II storage ring is the first one operating with both a plane-grating-monochromator (PGM) beamline equipped with multi-layer optics for the tender X-ray range, as well as with standard optical elements for the soft X-ray range. We discuss how this instrument has been used in various published NEXAFS-TXM studies to probe low dimensional nanostructures. This research work paves the way for understanding electronic structures approaching the atomic scale, and will thereby help in the design of tailored functional systems. • Nanoscale X-ray spectromicroscopy with a full-field X-ray microscope. • Nanoscale oxides in catalysis and light harvesting/storage applications. • X-ray spectromicroscopy studies of microelectronic devices. • X-ray spectromicroscopy studies of graphene based materials. • X-ray spectromicroscopy studies of nanomaterials for different sensor types. [ABSTRACT FROM AUTHOR]

The beamline, BL4U, in UVSOR-III Synchrotron is dedicated to scanning transmission X-ray microscopy (STXM) based on 2-dimensional soft X-ray absorption and has been in operation since 2013, to enable both academic and industrial users to carry out advanced chemical analysis under various sample environments. In this paper, we have summarized our major developments for the last decade; especially, expansion of the photon energy range down to the Li K-edge (55 eV), sample cryo-cooling to reduce radiation damage, 3-dimensional computer tomography, and air-free sample transfer. • Lithium K absorption edge around 55 eV is available for STXM by reducing higher order harmonics. • Cryo-cooling setup is developed to reduce X-ray radiation damage to samples. • By using computer tomography, 3-dimensional X-ray absorption spectroscopy of an isolated cell nucleus was performed. • Air-free sample transfer system is developed for samples which are highly reactive with oxygen or water. [ABSTRACT FROM AUTHOR]

In the last 30 years much effort was made in order to develop compact laser-produced plasma sources emitting short wavelength radiation, from the soft X-ray (SXR, λ = 0.1–10 nm), especially in the so-called “water window” (λ = 2.3–4.4 nm) and in the extreme ultraviolet (EUV, λ = 10–120 nm) spectral ranges. Investigations in the nanometer scale, employing short wavelengths, drive the need for developing table-top microscopes, to overpass the limitations imposed by large facilities, such as their high complexity, maintenance costs and the limited user access. In this paper we present our recent results related to nanoscale imaging using such table-top and desk-top EUV/SXR microscopes. Their construction is based on a double stream gas puff target laser plasma source. The double stream gas puff target EUV and SXR sources, coupled with Fresnel zone plates (FZPs) represent a suitable platform for microscopy experiments in transmission mode, employing SXR and EUV radiation. It represents a possible complementary technique to synchrotrons and free-electron laser facilities. The sources, which are very easy to be used by a single user, allow for efficient generation of plasma radiation with high SXR/EUV flux. Presented herein compact microscopes, based on that source, allow one to capture SXR and EUV images of various samples, with 50–60 nm half-pitch spatial resolution (corresponding to a Rayleigh resolution of 100–120 nm) and exposure time of the order of few seconds. Thus, herein, we would like to present our recent developments and progress in compact desk-top SXR/EUV microscopy employing laser plasma gas puff target sources, showing examples of acquired images and possible applications. [ABSTRACT FROM AUTHOR]

In its startup configuration the SASE3 beamline of the European XFEL provides only soft X-ray radiation, linearly polarized in the horizontal plane. In order to enhance capabilities of this beamline an afterburner scheme is proposed. It will be used as a coherent radiator using the micro-bunched electron beam of the linear SASE3 system. Radiation with variable polarization, which covers the full SASE3 wavelength range can be generated. For the radiator a new type of undulator design called Apple-X will be used. In this paper the design is described and magnet parameters, which are compatible with the SASE3 afterburner are determined using RADIA simulations. The end structure of such a device is optimized for minimum 1st field integrals. [ABSTRACT FROM AUTHOR]

Proffered Papers: Proffered papers 3: Sarcoma OC-0087: Preoperative Hypofractionated Radiation Therapy for Soft Tissue Sarcomas of Extremity and Trunk F. Navarria, A. Lauretta, E. Palazzari, R. Innocente, M. Gigante, A. Caroli, V. Canzonieri, A. Buonadonna, F. Gherlinzoni, J. Polesel, G. Bertola, A. De Paoli. [Extracted from the article]

A high-resolution cavity-based beam arrival/flight time measurement system has been established at SXFEL (Shanghai soft X-ray free-electron laser facility). During the development of the system, a correlation between the energy jitter and the beam flight time jitter was found which inspires and motivates us to further explore the possibility of using the beam arrival/flight time measurement system to measure the beam energy. On the one hand, beam energy is one of the most fundamental and critical parameters for accelerator facilities. Only precise handling of the beam energy enables precise control of the FEL (free-electron laser) radiation wavelength. On the other hand, there are only a few methods for beam energy measurement. The profile-based beam energy measurement method is commonly used but is interceptive. The BPM-based beam energy measurement scheme is non-interceptive but has a limited dynamic range and requires initial beam position calibration. This paper reports a promising application of a cavity-based high-resolution beam arrival/flight time measurement system: non-intercepting wide-range beam energy measurement. A brief introduction of the method principle and system implementation has been covered in this article. Moreover, a beam-based preliminary test has been performed and the test results show a linear correlation between the beam energy and the beam flight time under the current system configuration. The measured linear factor is 0.692 ps/MeV. In addition, the relative bunch energy measurement resolution is 0.0001. [ABSTRACT FROM AUTHOR]

In this paper we present in a first part the latest results of our group which are in relation with the study of DNA damages inflicted by low energy electrons (0-20 eV) in ultra-high vacuum as well as in air under atmospheric conditions. A short description of the drop-casting technique we developed to produce thin and nanometre-scaled DNA layers onto graphite sheets is given. We provide the absolute cross-section for loss of supercoiled topology of plasmid DNA complexed with 1,3-diaminopropane (Dap) in the vacuum under 10 eV electron impact and suggest a specific pathway for the dissociation of the transient negative ion formed by resonant capture of such a low energy electron (LEE) by the DNA's phosphate group when complexed to Dap. Well-gauged DNA-Dap layers with various nanometre-scaled thicknesses are used to evaluate the effective attenuation length of secondary photo-LEEs in the energy range (0–20 eV). The values of 11–16 nm for DNA kept under atmospheric conditions are in good agreement with the rare literature data available and which are stemming from computer simulations. In a second part, we describe the method we have developed in order to expose liquid samples of plasmid DNA to ultra-soft X-rays (Al Kα line at 1.5 keV) under hydroxyl radical scavenging conditions. We provide an experimentally determined percentage of indirect effects in aqueous medium kept under standard conditions of 94.7±2.1% indirect effects; in satisfactory agreement with the data published by others (i.e. 97.7%) relative to gamma irradiation of frozen solutions (Tomita et al., 1995). [ABSTRACT FROM AUTHOR]

The echo enabled harmonic generation (EEHG) scheme holds the ability for the generation of fully coherent soft x-ray free-electron laser (FEL) pulses directly from external UV seeding sources. In this paper, we study the feasibility of using a single stage EEHG to generate coherent radiation in the “water window” and beyond. Using the high-order operating modes of the EEHG scheme, intensive numerical simulations have been performed considering various three-dimensional effects. The simulation results demonstrated that coherent soft x-ray radiation at 150th harmonic (1.77 nm) of the seed can be produced by a single stage EEHG. The decreasing of the final bunching factor at the desired harmonic caused by intra beam scattering (IBS) effect has also been analyzed. [ABSTRACT FROM AUTHOR]

In this paper, we report a novel process for the fabrication of Fresnel zone plate (FZP) in poly methyl methacrylate (PMMA) using ultra-thin titanium film on carbon as sacrificial layer by electron-beam lithography at 30 keV with proximity correction. The process involves fabrication of free standing structure with high mechanical stability. A study was undertaken to understand the interaction of an electron beam in the resist stack, leading to the optimization of the process for high aspect ratio structures in a single step of exposure and development. The negative tone of PMMA was also utilized to provide mechanical strength to the structure. FZPs of 800 μm diameter were designed and fabricated for a capillary discharge based argon x-ray laser operating at 46.9 nm, to have a focal length of 25 mm. Each FZP had 165 zones with an outer most zone width of 1.34 μm, and a numerical aperture of 17 mrad. [ABSTRACT FROM AUTHOR]

Beam-based alignment and feedback systems are essential for the operation of the Free Electron Lasers (FELs) and Linear colliders. They require a certain number of beam position monitors (BPMs) at selected locations and that their resolution can reach hundreds of nanometers or even the order of nanometers. Cavity BPMs adopting a resonant cavity structure having the advantage of high position resolution are widely used in the field of accelerators. A typical system includes a cavity BPM pickup, a radio frequency signal conditioning front-end and a digital signal processing electronic. How to systematically analyze the impact of the key parameters of each subsystem on the performance of the whole system, and combine the requirements of the system, operation mode of the facilities, the current level of equipment processing and the development of the electronics, so as to achieve the optimal and balanced allocation of the key technical indicators of each subsystem, is the primary issue to be considered when designing a CBPM system. In this paper, based on theoretical analysis, the relationship between the relative amplitude extraction uncertainty of the CBPM system and the key parameters of each subsystem is proposed, which could provide clear guidance for the design and optimization of a CBPM system. In addition, considering the engineering requirements of the Shanghai High repetition rate X-ray Free Electron Laser and Extreme Light facility (SHINE) for beam position monitor, the allocation of the key technical indicators of the CBPM system using the optimized design method is also introduced. Accordingly, the development of each subsystem was completed, and the beam test bench was also built at the Shanghai Soft X-ray FEL facility (SXFEL), based on the evaluation method of divided power, the beam experiment results show that the position measurement uncertainty of the CBPM system can reach 40 nm at the bunch charge of 100 pC, which is consistent with the theoretical analysis results and better than the requirements of the SHINE. [ABSTRACT FROM AUTHOR]

Layered oxides have been investigated as electrode materials for Na-ion battery owing to its abundant species and easy preparation. Most of the layered oxides are sensitive to water and can't be applied to aqueous Na-ion battery. Layered anode Na 2 [Mn 3 Vac 0.5 ]O 7 with vacancies distributed uniformly in the transition-metal layer is moisture-stable, and the working potential is suitable for aqueous system. However, no effort has been devoted on the development aqueous Na-ion battery based on layered Na 2 [Mn 3 Vac 0.5 ]O 7. Moreover, the cycling and rate performance are poor. In this paper, we first proposed to change the local crystal structure by doping the vacancy with Ti4+ ions. Na 2 [Mn 3 Vac 0.1 Ti 0.4 ]O 7 was screened out with enhanced rate capability and cycling stability. As demonstrated by in-situ X-ray diffraction patterns and electrochemical impedance spectroscopy, the enhanced performance is ascribed to the improved kinetics after Ti doping at the vacancy, which facilitates fast transportation of electron and Na+ ion. Soft X-ray absorption results suggest that Mn4+/Mn3+ redox is involved in the charge transfer during the cycling process. Base on this, aqueous Na-ion cell was successfully fabricated using layered Na 2 [Mn 3 Vac 0.1 Ti 0.4 ]O 7 as anode for the first time, which exhibited excellent rate and cycle performance. [Display omitted] • Layered Na 2 [Mn 3 Vac 0.5- x Ti x ]O 7 is synthesized successfully and studied as anode materials for Na-ion batteries. • The negative electrode exhibits enhanced rate capability and cycling performance. • Kinetics is greatly improved after Ti doping, which facilitates fast transportation of electron and Na+ ions. • Aqueous Na-ion batteries was successfully fabricated with layered oxide, Na 2 [Mn 3 Vac 0.1 Ti 0.4 ]O 7 , as negative electrode material for the first time. • Synthetic atmosphere and carbon content have a great influence on the performance of P-1 type Na 2 [Mn 3 Vac 0.5 ]O 7. [ABSTRACT FROM AUTHOR]

X-ray free-electron lasers (XFELs) are powerful tools to explore and study nature for achieving remarkable advances. Generally, seeded FELs are ideal sources for supplying fully coherent soft x-ray pulses. Benefiting from the high-frequency up-conversion efficiency, the cascading configuration with echo-enabled harmonic generation (EEHG) and high-gain harmonic generation (HGHG) holds promising prospects for generating fully coherent radiation at 1 nm wavelength. In this paper, we design and optimize EEHG-HGHG configuration using parameters of Shanghai High-Repetition-Rate XFEL and Extreme Light Facility. In addition, we systematically analyze the effect of relative timing jitter on the output FEL performance based on various start-to-end electron beams. The intensive numerical simulations show that the cascaded EEHG-HGHG scheme can achieve 1 nm FEL pulses with peak power up to 15 GW. Further sensitivity analysis indicates that the relative timing jitter between the electron beam and seed laser has a significant impact on the FEL performance. The RMS timing jitter of 3 fs can lead to the final output pulse energy fluctuations of 29%. [ABSTRACT FROM AUTHOR]

Besides the designed beam acceleration, the energy of electrons is changed by the longitudinal wakefields in a real free-electron laser (FEL) facility, which may degrade FEL performances from the theoretical expectation. In this paper, with the help of simulation codes, the wakefields induced beam energy loss in the sophisticated undulator section is calculated for Shanghai soft X-ray FEL, which is a two-stage seeded FEL test facility. While the 1st stage 44 nm FEL output is almost not affected by the wakefields, it is found that a beam energy loss about 0.8 MeV degrades the peak brightness of the 2nd stage 8.8 nm FEL by a factor of 1.6, which however can be compensated by a magnetic field fine tuning of each undulator segment. And the longitudinal coherence of the 8.8 nm FEL output illustrates a slight degradation, because of the beam energy curvatures induced by the wakefields. [ABSTRACT FROM AUTHOR]

The last decades have witnessed substantial efforts in the development of several detector technologies for X-ray fluorescence (XRF) applications. In spite of the increasing trend towards performing, cost-effective and reliable XRF systems, detectors for soft X-ray spectroscopy still remain a challenge, requiring further study, engineering and customization in order to yield effective and efficient systems. In this paper we report on the development, first characterization and tests of a novel multielement detector system based on low leakage current silicon drift detectors (SDD) coupled to ultra low noise custom CMOS preamplifiers for synchrotron-based low energy XRF. This new system exhibits the potential for improving the count rate by at least an order of magnitude resulting in ten-fold shorter dwell time at an energy resolution similar to that of single element silicon drift detectors. [ABSTRACT FROM AUTHOR]

In metallic tokamaks, the interplay between particle transport and MagnetoHydroDynamic (MHD) activity might lead to impurities accumulation and finally to disruption. Studying such phenomena is thus essential if stationary discharges are to be achieved. Measuring the soft X-ray (SXR) radiation ([0.1 keV; 20 keV]) of magnetic fusion plasmas is a standard way of accessing valuable information on particle transport and MHD. Generally, like at Tore Supra (TS), the analysis is performed with a 2D tomographic system composed of several cameras equipped with silicon barrier diodes (SBD). On WEST the installation of an upper divertor masks many of the actual TS vertical diodes so that no proper tomography is possible. This paper presents the design of a new SXR diagnostic for the WEST project developed in collaboration with IPPLM (Poland) and the Warsaw University of Technology, based on a triple gas electron multiplier (GEM) detector. Preliminary simulations performed to size and position the detector and its electronics inside the vertical thimble are also presented, in particular estimation of magnetic field and temperature variation affecting GEM spatial resolution and signal quality. As a conclusion, perspectives about tomographic capabilities of the new system for studying impurity transport are given. [ABSTRACT FROM AUTHOR]

• An inclined light is adopted to manipulate the rolling of a straight LCE rod. • There exists an illumination angle range for triggering the self-sustained rolling. • The straight rod can roll spontaneously from the rest under the inclined light. • The rolling velocity can be controlled by the light intensity and illumination angle. The self-sustained motion of active materials has the great application values in the fields of soft robots, medical devices, micro nano devices, etc., due to its advantage of directly harvesting energy from the environment. Recent experiment has discovered that a straight liquid crystal elastomer (LCE) rod on a horizontal surface can roll continuously under the vertical light illumination, but the start of rolling requires external disturbance. In this paper, we adopt an inclined light to manipulate the rolling of a straight LCE rod, and theoretically study its rolling behaviors to obtain the illumination angle range for triggering the self-sustained rolling. It is found that the rolling of straight LCE rod can be triggered from rest without external disturbance under the inclined light, which is different from the case of the vertical light illumination. In addition, the rolling velocity of the LCE rod can be easily controlled by the light intensity and illumination angle. These predictions are consistent with the existing experimental results. This study may guide the potential applications of the optically-responsive rod in soft robots, harvesting energy and active machinery. [Display omitted] [ABSTRACT FROM AUTHOR]

Gd 2 O 2 S:Tb (P43) powder was widely used in soft X-ray detection due to its high light yield. Compared with P43, GAGG:Ce scintillator has high light transmittance, fast decay time and strong radiation resistance. Photonic crystals (PhCs) can be used to enhance the light output of scintillator. In this paper, two-dimensional (2D) photonic crystals that consist of square arrays of air holes etched into TiO 2 layer were fabricated on the exit surface of GAGG:Ce scintillator to enhance its light output. The luminescence spectra and the light output of GAGG:Ce scintillator with/without PhCs were measured at the BL08U1A beamline of Shanghai Synchrotron Radiation Facility. The results showed that the light output of GAGG:Ce scintillator with PhCs can be enhanced by a factor of 1.43 times compared with the reference GAGG:Ce scintillator, 2.35 times compared with YAG:Ce scintillator, 1.24 times compared with Gd 2 O 2 S:Tb scintillation ceramic and 0.76 times compared with P43 powder layer with the mass thickness of about 1.3mg/cm 2 with optical grease coupling. No significant change was observed in luminescence decay time between GAGG:Ce scintillator with and without PhCs. It makes GAGG:Ce scintillator with PhCs a promising material instead of P43 powder and YAG:Ce scintillator in soft X-ray detector. [ABSTRACT FROM AUTHOR]

In this paper, a low-temperature technology was introduced for the fabrication of PIN photodiode. A double dielectric oxide layers were prepared by nitric acid oxidation and PECVD, respectively. The selective epitaxial growth of SiGe thin layers, which were in-situ doped in a reactive thermal chemical vapor deposition system, were applied for the preparation of PN junction and high-low junction. A SiNx passivation layer combined with a post-annealing was adopted to lower the reverse current. The temperature was controlled below 450 °C for the whole fabrication process. Finally, the reverse current of 0.7 nA was achieved at room temperature for our 5 mm-diameter PIN detector and the energy resolution of 240 eV was obtained at 5.9 keV, −60 °C. The results indicated that the low-temperature technology is suitable for the fabrication of high quality PIN detector, and the cost can be reduced effectively. • PIN X-ray detector was fabricated using in-situ doped SiGe layers. • Low-temperature technology was applied. • The reverse current decreased when the dopant concentration increased in p-type SiGe thin films. • The energy solution of our new PIN detector was 240 eV when 55Fe radioactive source was used. [ABSTRACT FROM AUTHOR]

Abstract: The engineering and design of the soft X-ray Multi Camera Tomography System (XMCTS) in Wendelstein 7-X stellarator (W7-X) must fulfill several additional requirements compared to short pulse machines. The XMCTS has to withstand irradiation and electron cyclotron microwave loads in addition to being ultra high vacuum compatible, having low magnetic permeability and using low neutron activation materials (e.g. Co≤2000ppm). A further difficulty is the limited space inside the plasma vessel, which requires special engineering solutions. After detailed design development, supported by finite element analyses, prototypes have been manufactured and tested. At the end all test results have successfully proven that the components fulfill the requirements and that reliable and stable measurements will be possible with the XMCTS diagnostics during W7-X operation. The paper describes the design and the technological development, in particular on the electric multipin feedthrough (UHV barrier between in vessel detectors and the preamplifiers), the active cooling of the electronic components (reducing dark current/noise increase), the pneumatic shutter (protection of the detectors from sputtering and during baking) and the fiber optics illumination system (calibration of the detectors). [Copyright &y& Elsevier]

Time-resolved X-ray spectroscopies have the potential of unveiling ultrafast processes with chemical sensitivity, but their widespread application is still withheld by technical and experimental constraints on two levels: the count rate and the amount of signal to be measured. In this paper, we will give a brief overview of the available pulsed X-ray sources focusing in particular on those delivering photons with energies inside the water window (280–550 eV), thus allowing to access the C1s, N1s and O1s core levels which are relevant for the characterization of thin organic films and small molecules adsorbed on surfaces. We will mainly discuss the photon fluxes delivered by such sources in relation to their repetition rates, and we will see how these factors affect time-resolved measurements. The main purpose of this work is to discuss the most crucial parameter to adjust in pump-probe spectroscopies: the excitation density, which corresponds to the fraction of photoexcited molecules/atoms. We show that such quantity may be increased up to roughly 25% in gas phase and other robust samples, however, due to a lower damage threshold, in organic films it is typically constrained to be in the order of 1–5%. Despite the initially limited population of excited states in the latter case, we show that the evolution of the system may lead to a collective response of the material, which entirely modifies the measured core level line shape, thus providing a clear signal that may nonetheless offer valuable insights into the dynamics of the studied process. • The experimental challenges of time-resolved soft X-ray spectroscopies are outlined. • A formula for excitation density generated by optical pumping is derived. • In organic films the fraction of photoexcited molecules is usually as low as 1–5%. [ABSTRACT FROM AUTHOR]

INTEGRAL is an ESA mission in fundamental astrophysics that was launched in October 2002. It has been in orbit for over 18 years, during which it has been observing the high-energy sky with a set of instruments specifically designed to probe the emission from hard X-ray and soft γ -ray sources. This paper is devoted to the subject of black hole binaries, which are among the most important sources that populate the high-energy sky. We present a review of the scientific literature based on INTEGRAL data, which has significantly advanced our knowledge in the field of relativistic astrophysics. We briefly summarise the state-of-the-art of the study of black hole binaries, with a particular focus on the topics closer to the INTEGRAL science. We then give an overview of the results obtained by INTEGRAL and by other observatories on a number of sources of importance in the field. Finally, we review the main results obtained over the past 18 years on all the black hole binaries that INTEGRAL has observed. We conclude with a summary of the main contributions of INTEGRAL to the field, and on the future perspectives. [ABSTRACT FROM AUTHOR]

Abstract: This paper is focused on the soft X-ray tomography system set-up at Tore Supra (DTOMOX) and the recent developments made to get precise information about plasma features from a raw or inverted data. The ultimate aim is not only to use this information in real time for visualisation but also for potential feedback, with a particular emphasis on the optimisation of the reconstruction technique and on simple analysis tools developed for an automatic treatment of these inverted data. Recent progress made on the optimisation of free parameters used for the tomographic inversion will be explained. Finally, future techniques using advanced imaging detector will be presented. In particular, preliminary investigation on the use on Tore Supra of Gas Electron Multiplier (GEM) detector for imaging purposes will be described also including some first observations in situ. [Copyright &y& Elsevier]

Abstract: Progress toward a fundamental understanding of magnetism continues to be of great scientific interest and high technological relevance. To control magnetization on the nanoscale, external magnetic fields and spin polarized currents are commonly used. In addition, novel concepts based on spin manipulation by electric fields or photons are emerging which benefit from advances in tailoring complex magnetic materials. Although the nanoscale is at the very origin of magnetic behavior, there is a new trend toward investigating mesoscale magnetic phenomena, thus adding complexity and functionality, both of which will become crucial for future magnetic devices. Advanced analytical tools are thus needed for the characterization of magnetic properties spanning the nano- to the meso-scale. Imaging magnetic structures with high spatial and temporal resolution over a large field of view and in three dimensions is therefore a key challenge. A variety of spectromicroscopic techniques address this challenge by taking advantage of variable-polarization soft X-rays, thus enabling X-ray dichroism effects provide magnetic contrast. These techniques are also capable of quantifying in an element-, valence- and site-sensitive way the basic properties of ferro(i)- and antiferro-magnetic systems, such as spin and orbital moments, spin configurations from the nano- to the meso-scale and spin dynamics with sub-ns time resolution. This paper reviews current achievements and outlines future trends with one of these spectromicroscopies, magnetic full field transmission soft X-ray microscopy (MTXM) using a few selected examples of recent research on nano- and meso-scale magnetic phenomena. The complementarity of MTXM to X-ray photoemission electron microscopy (X-PEEM) is also emphasized. [Copyright &y& Elsevier]

Cavity Beam Position Monitor (CBPM) adopting a resonant cavity structure and using the characteristic modes excited by the electron beam to measure the beam parameters, has the advantage of high position resolution and is widely used in Free-electron Laser (FEL) facilities. The wake field of different modes carries different bunch information, the amplitude and phase of the signals of different modes can be extracted through the signal processing method to obtain the characteristic parameters of the source bunch. In the application of bunch charge and position measurement, the accurate amplitude extraction method for cavity BPM signal is the primary issue to be considered when designing the data acquisition and processing system. In this paper, through theoretical analysis and numerical simulation, it is proved that the optimal algorithm of amplitude extraction for CBPM exists, and the dependence between the data processing window size and the decay time of the cavity BPM under the optimal design is given. In addition, the relationship between the optimized amplitude extraction uncertainty and the noise-to-signal ratio, sampling rate of data acquisition and processing system, and the decay time of the cavity BPM is also proposed, which can provide clear guidance for the design and optimization of the CBPM system. Accordingly, the CBPM system in Shanghai Soft X-ray FEL (SXFEL) facility is optimized, and the resolution improved from 273 nm to 177 nm at the bunch charge of 500 pC. [ABSTRACT FROM AUTHOR]

• Activation and radwaste analysis was completed for ITER soft X-ray camera. • Combine specific activity and clearance index to determine the radwaste classification. • The linear relationship between the neutron flux and specific activity is obtained by expanding the neutron flux, so that the activation of SXR can be rapidly predicted. • The SXR model is simplified and integrated into ITER CLITE model. The Soft X-Ray camera (SXR) is designed to measure the polar profile of plasma X-ray emissivity with high spatial and temporal resolution. The camera is located on the Equatorial 12 Port Plug of ITER Tokamak. During the nuclear operation phase, a large number of high-energy neutrons are generated. These neutrons will activate the camera components and make them radioactive. In order to evaluate the activation of SXR's structural and shielding materials, an activation and radwaste analysis has been performed, and the results are summarized in this paper. A simplified model of all necessary parts of SXR is integrated into the ITER C-lite model for neutron transport. The activation of the components is calculated using the FISPACT-2007 code. The safety scenario SA2 for ITER activation calculations is recommended as irradiation history. The contact dose rate provides recommendations for the maintenance of SXR. The security risk of decay heat to SXR is analyzed. Specific activity and clearance index provide the basis for the classification of radwaste. The linear relationship between the neutron flux and activation parameters is obtained by expanding the neutron flux, so that the activation of SXR can be rapidly predicted according to the flux measured in the actual operation of ITER. [ABSTRACT FROM AUTHOR]

We present the assembly and preliminary results of a prototype detector, which was developed to evaluate the performance of the Topmetal-II − for application in Soft X-ray Polarimeter (SXP). SXP is used to measure the polarization of X-rays emitted from randomly occurring gamma-ray bursts (GRBs) and other specific dense celestial bodies. The Topmetal-II − is a silicon pixel sensor designed to directly track charged particles. The test was conducted on a gas mixture of Ne and DME at 0.8 atm pressure, and the Topmetal-II − sensor was used to image the photoelectron tracks. Typical real X-ray tracks obtained under four conditions are presented in this paper. The modulation factor derived from the tracks of 100% polarized 4.5 keV X-rays reached ∼ 29% at ∼ 53% signal efficiency, with a residual modulation of the order of ∼ 2% for unpolarized 5.9 keV X-rays. [ABSTRACT FROM AUTHOR]