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The suite of LED phosphors M2Si5N8:Eu2+ (M = Ca, Sr, Ba) emerged as indispensable solid-state light sources for the next-generation lighting industry and display systems due to their unique propert...

Charge exchange has been recognized as a primary source of soft X-ray emission in many astrophysical outflow environments, including cometary and planetary exospheres impacted by the solar wind. Some models have been set up by using different data collections of charge-exchange cross-sections. However, multiple-electron transfer has not been included in these models. In this paper, we set up a charge-exchange model with the inclusion of double-electron capture (DEC), and make a detailed investigation of this process on X-ray emissions of highly charged carbon, nitrogen, oxygen, and neon ions by using available experimental cross-sections. We also study the effect of different n-selective cross-sections on soft X-ray emission by using available experimental n-distributions. This work reveals that DEC enhancement on line intensity is linearly proportional to the ratio of ion abundance in the solar wind. It is more obvious for soft X-rays from carbon ions (C4+) in collision with CO2, and the enhancement on line intensity can be up to 53 per cent with typical ion abundances [Advanced Composition Explorer (ACE)] in the solar wind. The synthetic spectra with parameters from the Ulysses mission for the solar wind reveal velocity dependence, target dependence, as well as the non-negligible contribution from the DEC.

Real-time observation of an electrochemical reaction at a solid–liquid interface was performed using fluorescence-yield wavelength-dispersive soft X-ray absorption spectroscopy (XAS). A dedicated e...

Novel light sources have been new probes or “eyes” to develop our science and technology. Soft X-ray free-electron lasers (SXFELs) are an ultrahigh brilliant soft X-ray source with ultrashort pulse...

Soft X-ray absorption spectroscopy (XAS) observes element-specific intermolecular interactions of light elements in liquid phase through the core-to-valence excitation. We have newly developed liqu...

PolarLight is a compact soft X-ray polarimeter onboard a CubeSat, which was launched into a low-Earth orbit on October 29, 2018. In March 2019, PolarLight started full operation, and since then, regular observations with the Crab nebula, Sco X-1, and background regions have been conducted. Here we report the operation, calibration, and performance of PolarLight in the orbit. Based on these, we discuss how one can run a low-cost, shared CubeSat for space astronomy, and how CubeSats can play a role in modern space astronomy for technical demonstration, science observations, and student training., Comment: accepted for publication in Advances in Space Research

We proposed a data-driven science study by Bayesian spectroscopy to analyze an X-ray magnetic circular dichroism (XMCD) spectrum and magnetic moments. In Bayesian spectroscopy, model selection beco...

The paper presents the results of processing of data on the soft X-ray solar radiation obtained by the PINGVIN-M instrument aboard the KORONAS-FOTON spacecraft in July 2009. The high sensitivity of the device, combined with effective compensation for the magnetospheric background over most of the orbit, made it possible to study in detail the evolution of X-ray radiation from the active region and its X-ray bursts—from microflares to class-C bursts. The analyzed data refer to the period of deep minimum solar activity, during which there was only one active region emitting in the soft X-ray range on the solar disk. This made it possible to study the characteristics of soft X-ray radiation in this region without additional background with a device that records radiation from the entire solar disk, which significantly increases the reliability of the estimates of the parameters of the time and energy spectra of X-ray radiation derived from experimental data.

A layered manganese oxide catalyst containing K+ cations [K/MnOx catalyst] was developed, and its ability to efficiently decompose water was demonstrated. Operando hard/tender/soft X-ray absorption...

A third-order aberration analytical analysis method of soft X-ray optical systems with orthogonal and coplanar arrangement of the main planes of elements is proposed. Firstly, the transfer equations of the aperture ray and the principle ray are derived; then, based on the third-order aberration theory with the aperture-ray coordinates on the reference exit wavefront of a plane-symmetric optical system, the aberration expressions contributed by the wave aberration and defocus of this kind of optical system are studied in detail. Finally, the derived aberration calculation expressions are applied to calculate the aberration of two design examples of such types of optical systems; the images are compared with ray-tracing results obtained using the Shadow software to validate the aberration expressions. The study shows that the accuracy of the aberration expressions is satisfactory. The analytical analysis method of aberration is helpful in the design and optimization of the soft X-ray optical systems with orthogonal and coplanar arrangement of the main planes of optical elements.

The success of a neutron or X-ray scattering experiment relies on sufficient signal from the system being studied. The intensity of scattered radiation depends on instrument resolution, the structu...

Molecular orientation anisotropy can be critical in functional organic thin films. For instance, it is known that molecular orientation can affect the performance of organic electronic devices such...

A monolithic Wolter-type mirror with large acceptance, achromatism and small comatic aberration was designed and evaluated at the soft X-ray beamline BL25SU of SPring-8., A focusing optics that can provide a sub-micrometre high-flux probe for soft X-ray micrometre-scale angle-resolved photoemission spectroscopy (ARPES) is proposed. A monolithic Wolter-type mirror with a large acceptance, achromatism and small comatic aberration was designed and evaluated. A focused beam size of 0.4 µm (vertical) × 4 µm (horizontal), a high throughput of 59% and a high tolerance of 1.6 mrad to the pitching error were realized at a photon energy of 1000 eV. A Wolter-type mirror can be practically employed as a stable sub-micrometre focusing mirror with high throughput in ARPES applications.

Wide-angle soft X-ray scattering on free silica particles of different porosity prepared in a beam is reported. The explored q region is mostly dominated by features due to surface roughness and bu...

Using X-ray absorption spectroscopy (XAS), we investigated local chemical interactions in thermosetting epoxy resins for structural composites: N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane (...

Strongly correlated transition metal oxides continue to be widely studied due to the many interesting and potentially useful properties they exhibit, including superconductivity, various forms of e...

Multifunctional light stimuli-responsive NO-based gaseous theranostic systems are highly desirable due to them directly killing cancer cells at high concentration (>1 μM) with minimized adverse effects. However, on-demand NO-releasing nano-platforms for deep-tissue gas-based cancer therapy have not yet been explored. Herein, we develop a new type of soft X-ray-activated NaYF4:Gd/Tb scintillator as a light transducer for depth-independent NO release and on-demand gas-sensitized cancer therapy. Benefiting from the excellent radioluminescent property of NaYF4:Gd/Tb, deep-tissue (up to 3 cm) NO release can be achieved by ultralow dosage soft X-ray (45 kVp, 0.18–0.85 mGy) irradiation. More importantly, the designed scintillator-based NO gasotransmitter presents significant inhibition of tumor growth under ultralow dosage soft X-ray irradiation. Therefore, such a soft X-ray activated NO-releasing nanoplatform provides a promising depth-independent gaseous therapy mode for defeating deep-seated cancer in the future.

The latest experimental results of studying beryllium-containing multilayer mirrors are reviewed. The mirrors are of interest for projection nanolithography, solar astronomy, X-ray microscopy, and other applications. It is shown that for a number of ranges beryllium-containing multilayer mirrors outperform the world analogues in their X-ray optical characteristics.

The shape of soft X-ray spectra and energy confinement dynamics is studied in experiments on central ECR heating with a power to 1 MW using the L-2M stellarator. It is shown that the spectra remain two-temperature with increasing heating power. In this case, the average electron energy in the epithermal spectral region increases reaching 25% of the average energy over the entire spectrum at an ECR heating power of 950 kW. It is shown that the plasma confinement energy in the L-2M stellarator gradually decreases at heating powers above 700 kW, which is associated with an increase in the plasma radiative loss power, caused by impurity accumulation.

Mesoporous titanium peroxide TiOx nanospheres with a high surface area are synthesized for the application of an advanced drug system. The mesoporous TiOx nanospheres have a high specific surface a...

Scan free grazing emission X ray fluorescence spectroscopy GEXRF is an established technique for the investigation of the elemental depth profiles of various samples. Recently it has been applied to investigating structured nanosamples in the tender X ray range. However, lighter elements such as oxygen, nitrogen or carbon cannot be efficiently investigated in this energy range, because of the ineffective excitation. Moreover, common CCD detectors are not able to discriminate between fluorescence lines below 1 keV. Oxygen and nitrogen are important components of insulation and passivation layers, for example, in silicon oxide or silicon nitride. In this work, scan free GEXRF is applied in proof of concept measurements for the investigation of lateral ordered 2D nanostructures in the soft X ray range. The sample investigated is a Si3N4 lamellar grating, which represents 2D periodic nanostructures as used in the semiconductor industry. The emerging two dimensional fluorescence patterns are recorded with a CMOS detector. To this end, energy dispersive spectra are obtained via single photon event evaluation. In this way, spatial and therefore angular information is obtained, while discrimination between different photon energies is enabled. The results are compared to calculations of the sample model performed by a Maxwell solver based on the finite elements method. A first measurement is carried out at the UE56 2 PGM 2 beamline at the BESSY II synchrotron radiation facility to demonstrate the feasibility of the method in the soft X ray range. Furthermore, a laser produced plasma source LPP is utilized to investigate the feasibility of this technique in the laboratory. The results from the BESSY II measurements are in good agreement with the simulations and prove the applicability of scan free GEXRF in the soft X ray range for quality control and process engineering of 2D nanostructures. The LPP results illustrate the chances and challenges concerning a transfer of the methodology to the laboratory

Soft X-ray spectra coming from the ECR heating region, non-distorted by the effect of the plasma-wall interaction, are measured at the L-2M stellarator in experiments on axial and off-axial ECR heating. In both cases, the measured soft X-ray spectra turned out to be non-Maxwellian. It was found that the electrons forming the suprathermal spectral region are produced in the heating region, but do not come from the plasma-wall interaction region.

Bacterial chromosomic DNA is packed within a membrane-less structure, the nucleoid, thanks to proteins called Nucleoid Associated Proteins (NAPs). The NAP composition of the nucleoid varies during the bacterial life cycle and is growth phase-dependent. Among these NAPs, Hfq is one of the most intriguing as it plays both direct and indirect roles on DNA structure. Indeed, Hfq is best known to mediate post-transcriptional regulation by using small noncoding RNA (sRNA). Although Hfq presence in the nucleoid has been demonstrated for years, its precise role is still unclear. Recently, it has been shown in vitro that Hfq belongs to the bridging family of NAPs. Its bridging mechanism relies on the formation of the amyloid-like structure of Hfq C-terminal region. Here, using cryo soft X-ray tomography imaging of native unlabelled cells and using a semi-automatic analysis and segmentation procedure, we show that Hfq significantly remodels the Escherichia coli nucleoid, especially during the stationary growth phase. Hfq influences both nucleoid volume and absorbance. Hfq cumulates direct effects and indirect effects due to sRNA-based regulation of other NAPs. Taken together, our findings reveal a new role for this protein in nucleoid remodelling that may serve in response to stress conditions and in adapting to changing environments. This implies that Hfq regulates nucleoid compaction directly via its interaction with DNA, but also at the post-transcriptional level via its interaction with RNA.

Aqueous aerosols are important in atmospheric chemistry, drug delivery, and human health. X-ray photoelectron spectroscopy (XPS), a surface-sensitive technique and near-edge X-ray absorptionfine structure (NEXAFS) spectroscopy which informs on the bulk, is deployed to study the solvation of ammonium nitrate (NH4NO3). Aerosolised solutions of NH4NO3 were introduced into a photoelectron spectrometer via an aerodynamic lens, and interrogated with soft X-ray photons, the resulting electrons were imaged via velocity map imaging. Density functional theory calculations were performed to compare with the measured binding energies of NH4+ and NO3− solvated in water. The results reveal that the nitrate anion has a slight propensity for the surface, while both ammonium and nitrate ions are present in equal measure in the bulk.

We present our $AstroSat$ soft X-ray observations of a compact binary system, AR Sco, and analysis of its X-ray observations with $Chandra$ that were taken only about a week before the $AstroSat$ observations. An analysis of the soft X-ray ($0.3-2.0$ keV) data limits the modulation of the spin, orbital, or beat periods to less than 0.03 counts s$^{-1}$ or $, Comment: 9 pages, 8 figures, to be published in the Journal of Astrophysics and Astronomy

In magnetic Cataclysmic Variables (mCVs), X-ray radiation originates from the shock heated multi-temperature plasma in the post-shock region near the white dwarf surface. These X-rays are modified by a complex distribution of absorbers in the pre-shock region. The presence of photo-ionized lines and warm absorber features in the soft X-ray spectra of these mCVs suggests that these absorbers are ionized. We developed the ionized complex absorber model zxipab, which is represented by a power-law distribution of ionized absorbers in the pre-shock flow. Using the ionized absorber model zxipab along with a cooling flow model and a reflection component, we model the broadband Chandra/HETG and NuSTAR spectra of two IPs: NY Lup and V1223 Sgr. We find that this model describes well many of the H and He like emission lines from medium Z elements, which arises from the collisionally excited plasma. However the model fails to account for some of the He like triplets from medium Z elements, which points towards its photo-ionization origin. We do not find a compelling evidence for a blackbody component to model the soft excess seen in the residuals of the Chandra/HETG spectra, which could be due to the uncertainties in estimation of the interstellar absorption of these sources using Chandra/HETG data and/or excess fluxes seen in some photo-ionized emission lines which are not accounted by the cooling flow model. We describe the implications of this model with respect to the geometry of the pre-shock region in these two IPs., 12 pages, 7 figures, 4 tables. Accepted for publication in ApJ