OpenAccess

We report the first direct experimental observations of resonance island formation in a hybrid multibend achromat (HMBA) storage ring lattice. Using a low-emittance electron beam, we achieved high-precision measurements that resolve the onset, evolution, and transient dynamics of particle capture near resonance islands. [...]

Traditional x-ray photoelectron spectroscopy (XPS) relies upon a direct mapping between the photoelectron binding energies and the local chemical environment, which is well characterized by an electrostatic partial charges (PC) model for systems in equilibrium. However, the extension of this technique to out-of-equilibrium systems has been hampered by the lack of x-ray sources capable of accessing multiple atomic sites with high spectral and temporal resolution, as well as the lack of simple theoretical procedures to interpret the observed signals. [...]

Nonlinear spectroscopic techniques using entangled photon pairs can provide an opportunity to exploit non-classical correlations encoded in two-photon wave functions to manipulate two-exciton wave functions. We propose an entangled photon pair-enhanced multidimensional spectroscopic technique that is sensitive to exciton–exciton interactions and correlations at the femtosecond timescale. [...]

The ID11-L HESEB Soft X-ray beamline and end station significantly enhance soft X-ray research capabilities. Operating in an energy range of 90–1800 eV, extendable to 70–2000 eV, the beamline achieves high performance with an energy resolution of E/ΔE > 8000 and a photon flux of 10$^{10}$ to 3.4 × 10$^{12}$ photons/s. [...]

The TR-XPES (Time Resolved X-Ray Photoelectron Spectroscopy) setup is the first experimental station integrated at the Soft X-ray Port (SXP) instrument of the European XFEL. It has been developed to perform femtosecond time resolved photoelectron spectroscopy experiments on solid state samples in the soft X-ray photon energy range from 0.25 keV to 3 keV, generated by the SASE3 undulator system. [...]

In a coherent scattering experiment, one of the important experimental parameters is the speckle visibility, which can be changed by adjusting the size of the X-ray beam on the sample. Focussing optics provide therefore a convenient tool to increase the speckle visibility, while simultaneously increasing the flux density and thus the dose on the sample. [...]

This paper studies the 𝑝-biharmonic equation on graphs, which arises in point cloud processing and can be interpreted as a natural extension of the graph 𝑝-Laplacian from the perspective of hypergraphs. The asymptotic behavior of the solution is investigated for the random geometric graph when the number of data points goes to infinity. [...]

Up to six superconducting undulator (SCU) modules are foreseen to be installed downstream with respect to the permanent magnet undulators of SASE2, one of the two hard X-ray lines at European XFEL. Aim is to provide users with photon energies above 30 keV. [...]

A ubiquitous feature of accreting black hole systems is their hard X-ray emission which is thought to be produced through Comptonization of soft photons by electrons and positrons in the vicinity of the black hole, in a region with optical depth of order unity. The origin and composition of this Comptonizing region, known as the corona, is a matter open for debate. [...]

Traditional x-ray photoelectron spectroscopy (XPS) relies upon a direct mapping between the photoelectron binding energies and the local chemical environment, which is well characterized by an electrostatic partial charges (PC) model for systems in equilibrium. However, the extension of this technique to out-of-equilibrium systems has been hampered by the lack of x-ray sources capable of accessing multiple atomic sites with high spectral and temporal resolution, as well as the lack of simple theoretical procedures to interpret the observed signals. [...]