We present a summary of the Czech contribution to the EU H2020 Project AHEAD2020 with emphasis on the X-RAY OPTICS work package where innovative Lobster Eye (LE) and Kirpatrick Baez (KB) modules based on Multi Foil Optics technology (MFO) were studied. The LE X- ray optics is a wide field of view (FOV) optics type Lobster Eye (LE) with short focal length (suitable for cubesat application) based on Schmidt design. The 2D LE optics consists of two orthogonal sub-modules of flat smooth reflective foils and each sub-modules focuses in one direction. The advantage of MFO LE is that for off-axis points the angular resolution is preserved throughout the FOV, as demonstrated by simulations and measurements. In addition, two major events were organized, namely a workshop in December 2023 and a summer school in May 2024.

The lobster eye shows a specific point-spread function (PSF). The PSF consists of a cross and spots around the cross. The cross consists of focal spot and four arms. The analysis how much radiation is collected to each of these parts is presented. The analysis is done for lobster eye with reflecting surfaces of ideal reflectivity and few reflectivity models. Results are demonstrated on ray-tracing simulations. The results have an important consequence: If a smart image processing algorithm (e.g. deconvolution) that utilizes not only the focal spot but all the focal cross is used then the utilized collecting area of the optics is increased.

The Einstein Probe (EP) dedicated to time-domain astronomy to monitor the sky in the soft X-ray band, was launched in Jan 2024. It is in normal operation led by the Chinese Academy of Sciences with international collaboration. Its wide-field imaging capability is achieved by using established technology of the micro-pore lobster-eye X-ray focusing optics. In this talk, we will briefly present the developments of Micro-Pore optics, a Lobster-eye telescope, covering a FOV of about 3830 square degrees. The performances of MPO chips for flight, the automatic mounting facility as well as the performance of all the optics assemblies will be presented. A nova way to achieve the 1 arcmin MPO optics will also be proposed.

We report on the status of an X-ray optics development effort at Goddard Space Flight Center. The development effort is designed to enable future flagship missions like Lynx in the long term and to support Probe missions and Explorer missions like AXIS, HEX-P, and LEM, in the near term. It takes into consideration the three major work areas of building an X-ray mirror assembly, i.e., technology, engineering, and production, while focusing its resources on developing and maturing a technology based single crystal silicon. Boiled down to the most essentials, the development tackles four major technical areas: fabrication, coating, alignment, and bonding of thin, lightweight mirror segments. The technology is based on single crystal silicon, whose lack of internal stress makes it possible to use many polishing techniques to make the best possible thin, lightweight mirror segments. We will report results achieved with repeated building and testing mirror modules, as well as knowledge and lessons learned in each of the four technical areas.

The “Deutsches Röntgenmuseum” in Remscheid is the unique institution worldwide that researches and documents the life and work of the first Nobel Prize winner, Wilhelm Conrad Röntgen, and the effects of his discovery of X-rays. As an integral part of the museum, the RöLab laboratory offers visitors the opportunity to gain practical experience in X-rays, optics and technology through own experiments. As part of a joint development project, students from Aschaffenburg University of Applied Sciences are currently designing a visitor experiment on astronomical X-ray optics for the museum laboratory. An optical set-up with visible light illustrate the focusing principle of X-ray telescopes, e.g. for wide-angle optics based on the lobster-eye principle. Display boards explain the optics of various types of telescopes with accompanying text and corresponding illustrations. Modern X-ray observatories such as CHANDRA, XMM-Newton and eROSITA are presented clearly. Once implemented, the new visitor experiment inside the “Deutsches Röntgenmuseum” intend to inspire young researchers for the fascinating world of X-ray optics and X-ray astronomy.

Although the organic molecule dopamine (3,4-dihydroxyphenethylamine) is commonly known as the “hormone of happiness”, thin polymer films of poly-dopamine also have interesting technical properties. When produced by dip coating, these self-organizing layers grow in a reproducible thickness of single or multiple molecule monolayers of a few nanometre thickness only. One application is the use of thin poly-dopamine overcoatings to increase the soft X-ray reflectivity of astronomical X-ray mirrors. We thereby introduce a method of determining the layer thickness of poly-dopamine, which is based on spectroscopic ellipsometry measurements and applies an optical model for the poly-dopamine layers including their dielectric function. Furthermore, we give an outlook to other technical applications for this promising material, presenting this bio-inspired organic polymer as an innovative technical solution for the future.

The poster presents description of LOPSIMUL ray-tracing simulation software that offers extremely high computational rate. LOPSIMUL has not a specific requirements for computer hardware and the computing time is less than one second or few seconds on a common personal computer. The software is optimized for lobster eye reflective optics (Angel as well as Schmidt variants) and various types of multi-foil optics. These systems are commonly used for X-rays. As the optimization supposes a specific optics design, the software cannot be used for a generic optics. Lopsimul draws focal image and x and y profiles. LOPSIMUL calculates FWHM, effective collecting area and other principal results.

The space radiation field in LEO orbit is measured and characterized in high-resolution and wide range by the miniaturized (100 g) low-power (2 W) particle tracker detector "MiniPix-Timepix3 Space" deployed as a radiation monitor in LEO orbit (600 km, polar sun synchronous) onboard the JoeySat One Web telecommunications satellite (150 kg) launched in May 2023. Timepix3 provides quantum imaging sensitivity [1], particle-type resolving power [2], high-resolution spectral response (energy loss, linear-energy-transfer LET) [3] and wide field-of-view directional-tracking information [4]. Particle fluxes (total, partial) and dose rates (total, partial) are produced in wide range (over 8 orders of magnitude) together with charged particle (proton, electron) LET spectra (range 0.01 – 500 keV/µm in silicon). The X-ray component is resolved and analyzed with navigation-time stamp into detailed radiation maps along the satellite orbit. References [1] C. Granja, S. Pospisil, “Quantum Dosimetry and Online Visualization of X-ray and Charged Particle Radiation in Aircraft at Operational Flight Altitudes with the Pixel Detector Timepix”, Adv. Space Research 54 (2014) 241-251 [2] C. Granja, J. Jakubek, S. Polansky, et al., Resolving power of pixel detector Timepix for wide-range electron, proton and ion detection, Nuclear Instr. Methods A 908 (2018) 60-71 [3] C. Granja, C. Oancea, J. Jakubek, et al., Wide-range tracking and LET-spectra of energetic light and heavy charged particles, Nucl. Instrum. and Methods A 988 (2021) 164901 [4] C. Granja, K. Kudela, J. Jakubek, et al., Directional detection of charged particles and cosmic rays with the miniaturized radiation camera MiniPIX Timepix, Nuclear Instr. Methods A 911 (2018) 142-152 [5] C. Granja, Z. Vykydal., A. Owens, S. Pospisil, et al., The SATRAM Timepix spacecraft payload in open space on board the Proba-V satellite for wide range radiation monitoring in LEO orbit, Planetary and Space Science 125 (2016) 114-129

The X-ray Imaging and Spectroscopy Mission (XRISM), an international JAXA/NASA collaboration including participation from ESA, is an advanced X-ray observatory carrying out a science program that will address some of the most important questions in astrophysics in the 2020s. Resolve, the primary instrument, is a high-resolution, non-dispersive X-ray spectrometer, providing high-resolution (~5 eV) spectroscopic imaging capabilities in in the ~2-12 keV band, with a response peaking around the ubiquitous 6.4 keV Fe K-alpha line. A wide-field imager, Xtend, offers simultaneous coverage over nearly a 40’ square field of view, with ~1’ angular resolution. XRISM is observing a wide variety of astrophysical objects, including galaxies and clusters, AGN, X-ray binaries, supernova remnants, and transient phenomena. This talk will highlight the on-orbit performance of XRISM and its instruments and some of the early science results.

SRG/eROSITA has made it possible for the first time to separate the heliospheric foreground emission from the diffuse X-ray sky beyond, on a global scale and on a baseline of more than two years. In this presentation we focus on the observed spectral properties of the heliospheric X-ray emission. This is challenging, because the emission is faint, while the pronounced temporal variability requires to perform the analysis on a high number (about 10^5) of samples. We describe how we have faced this challenge by finding a suitable spectral model with only 3 free parameters and by developing a fitting method which is so efficient that 10^5 spectra can be processed within 30 s. We find that (i) the observed spectral properties can be reproduced by charge exchange interactions between C, N, and O ions in the solar wind and interstellar Helium, that (ii) there is substantial short-term variability in the CNO abundances, that (iii) there is a long-term trend of increasing CNO from solar minimum towards solar maximum, and that (iv) the increase rate raises with atomic number.

We discuss how combining the observations of various X-ray monitors onboard different satellites can be helpful for investigating the long-term activity of a given object using the light curves of the 1-day means. We show how observing the activity of X-ray binaries can contribute and how combining the MAXI/ISS data with those obtained by the monitor BAT onboard Swift can be helpful if the light curves containing the 1-day means are used. Combining observations from MAXI/ISS and BAT/Swift enables the investigation of long-term activity at energies between 2 keV and 50 keV. We show examples of several X-ray sources containing compact objects accreting matter from their companions. We analyzed the typical features of the activity that are distinguishable on the light curves with a 1-day binning. We show the features for which observing with this binning is sufficient. This provides the scientific potential to investigate the role of various physical mechanisms.

The AXRO history is related to the history of X–ray astronomy in general and to the history of X-ray optics developments in the Czech Republic (and formerly in Czechoslovakia) in particular. The first Czech X-ray mirror was built already in the years 1969/1970, for a solar telescope within the Eastern Europe/Soviet INTERKOSMOS program, There were also essential efforts devoted to the development of novel technologies for satellite projects which were either canceled or interrupted. The two wasted years of development on the technology of high-quality Ni foils for the Danish SODART telescope (Schnopper, 1990), 1986-1988, can serve as an example. The SOviet-DAnish Roentgen Telescope (SODART) was planned for on board the Spectrum Roentgen Gamma (SRG) satellite equipped with three different instruments devoted to X–ray spectroscopy. Each of the two thin foil telescopes had an 8m focal length, a 60 cm diameter, a 1 deg field-of-view (FOV), a half-power width better than 2 arcmin and ca. 1 700 and 1 200 cm2 collecting area at 2 and 8 keV, respectively. In the last three decades developments of innovative technologies for X-ray optics continued with an emphasis on glass foils and silicon wafers mostly in Multi Foil Optics arrangements and Schmidt Lobster Eye and Kirkpatrick Baez geometries.