Current Issue : July-September Volume : 2026 Issue Number : 3 Articles : 5 Articles
Additive manufacturing offers a promising route to low-cost, rapidly deployable X-ray focusing optics with geometries that are difficult to realize by conventional machining. Here, we report polymer compound refractive lenses (CRLs) for hard X-ray focusing fabricated by projection micro-stereolithography (PμSL, DLP-based) and by two-photon polymerization (2PP). Two-dimensional bi-parabolic CRL elements were produced in multiple photopolymer resins (HTL, Tough, ST1400 for PμSL; IP-S for 2PP) and evaluated by at-wavelength metrology at the Shanghai Synchrotron Radiation Facility. The single-lens residual phase errors (RMS) less than 0.1 λ were measured for PμSL-fabricated HTL, and Toughlenses, respectively, while 2PP-fabricated IP-S lenses achieved 0.008 λ. And the analysis indicates that PμSL lenses are primarily limited by systematic mid-order aberrations, whereas 2PP substantially suppresses coma but shows residual spherical aberration attributable to process calibration and shrinkage. Leveraging the higher fidelity of 2PP, a 65-element parabolic CRL array (radius of curvature of 100 μm) was fabricated and demonstrated hard X-ray focusing at 15 keV with focal spot sizes of 6.4 ± 1 μm (H) and 6.8 ± 1 μm (V), and a flux gain of 220. The measured performance agrees with theoretical expectations when accounting for X-ray source properties, detector resolution and chromatic aberration. These results establish a practical pathway for additively manufactured polymer CRLs with DLP and 2PP techniques as compact, customization focusing optics for synchrotron beamlines....
The beam-shaping condenser (BSC) has become a key optical component in X-ray microscopy, providing a wide field of view with stable and uniform illumination. However, alternating bright and dark fringes often appear at the focal spot, compromising illumination uniformity. To elucidate the formation mechanism of these diffraction fringes, this study conducted theoretical analyses and numerical simulations. Based on this, a defocused illumination approach was developed to alter the focal positions and spatial relative phases of the subgratings, thereby enhancing illumination uniformity. The influence of defocused illumination on fringe patterns and intensity distribution was systematically investigated. To validate this approach, a BSC with a Fresnel number of 20 and a 60 mm 60 mm field of view was fabricated and tested at the soft X-ray imaging beamline of the Hefei Light Source. Experimental results demonstrate that the device achieves uniform top-hat illumination across the full field, effectively suppressing diffraction-induced artifacts. This work offers an efficient and practical approach for achieving wide-field uniform illumination in X-ray microscopy....
Aims. The spectral analysis of two XMM-Newton observations of the high-mass X-ray binary system Cen X−3 is presented. In particular, it is focused on the eclipse and out-of-eclipse spectra in order to compare the properties of the environment around the compact object. Methods. The high-resolution spectra obtained from the reflection grating spectrometer on board XMM-Newton were analysed, with a focus on studying eclipse and out-of-eclipse spectra separately. Several continuum models were explored in SPEX, for which we studied the properties of emitting and absorbing matter depending on the emission and absorption lines identified in the spectra. Results. It was found that the X-ray continuum is heavily absorbed by a neutral gas and photoionised matter. Emission lines from Si v, Mg xii, Mg xi, and Ne x were detected in the eclipse spectrum; in particular, H-like lines of Mg and Ne with a significance of 5σ in the eclipse spectrum and ∼3σ in the out-of-eclipse spectrum. However, in the out-of-eclipse spectrum any absorption lines were detected with a significance of less than 2σ. RGS light curve showed dips in the out-of-eclipse spectrum that are not due to an increase in the column absorption but that may be produced by instabilities in the accretion stream. On the other hand, the level of counts above 20Å was compatible with the X-ray background. A simple local continuum model was used to describe the He-like triplet of Ne and the derived values of R and G ratio parameters pointed out that the UV photospheric field should be important at the line production site and an electron density greater than 1012 cm−3. As a consequence, a hybrid plasma may be present in the binary system....
The successful detection of X-ray polarization from many celestial sources belonging to different classes by the IXPE mission has opened a new window in X-ray astronomy. While an impressive number of scientific topics have already been addressed by IXPE, many of them would benefit from a new class of instrumentation that could be launched on a relatively short time scale. In this contribution, we present the development activities of a focal-plane polarimeter whose goal is to extend the energy range of IXPE up to tens of keV, with better sensitivity and lower background. Our design is based on the use of multilayer mirrors and stacked instrumentation, comprising either a low- or mediumenergy imaging photoelectric polarimeter and an active Compton polarimeter. Such an approach relies on hardware with flight heritage and—although still under development for the specific application in X-ray polarimetry—it has the potential to answer compelling scientific questions and to soon become competitive from the point of view of feasibility for space applications....
In X-ray imaging, tissue scattering is an important factor that degrades image clarity, especially using a portable gridless X-ray imaging device. This study focuses on using Monte Carlo simulation to quantify the effect of scatter radiation on image resolution, by analyzing the point spread function (PSF) and the corresponding modulation transfer function (MTF). Lateral energy absorption profiles in tissue and a cesium iodide (CsI) scintillator were calculated at different X-ray tube voltages (70–90 kV) and filter configurations. Results showed that 85.7% of the total scattered radiation is concentrated at a distance of 4 cm from the central axis for the tissue and 67.37% for the CsI scintillator. The MTF remained high at low spatial frequencies (23% at 0.04 cycles/cm) but dropped at mid frequencies (0.015–0.025 at 0.3–0.6 cycles/cm) and was almost zero at high frequencies (0.004 at 0.8 cycles/cm), indicating loss of detail due to scattering. Increasing the thickness of the filter or adding a copper (Cu) filter reduced the contrast at low spatial frequencies (from 23% to 21%). The study quantitatively investigated the MTF degradation in portable X-ray imaging devices without grid, due to scatter. These results may aid in the development of scatter correction algorithms to improve image quality without the need for an anti-scatter grid....
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