Documents in process

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. [...]

In this paper, we present a design of a high-efficiency high-gain free-electron laser oscillator based on the use of a strongly tapered undulator for extracting energy from high-brightness electron beams. We provide an analytical model of the setup followed by numerical simulations for lasing at the wavelength of 13.5 nm. [...]

We report the first direct experimental observations of resonance island formation in a hybrid multibendachromat (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. [...]

The reflectivity and optical quality of laser pulses reflected off 125 μm Kapton™ tape was investigated for use as a repeatable plasma mirror. Reflectivities of around 70% were measured at ≈2 × 10$^{21}$ Wm$^{−2}$ while maintaining the quality of the laser beam. [...]

Preserving the quality of positron beams in plasma-based accelerators, where wakefields are generated in electron filaments, is challenging. These wakefields are characterized by transversely non-linear focusing fields and non-uniform accelerating fields. [...]

Recent theoretical advancements propose multiple positron acceleration schemes in plasma wakefield acceleration (PWFA). One of the most promising ideas involves the creation of an electron-driven blowout wake within a finite-radius pre-ionized plasma column. [...]

Using realistic laser profiles for simulations of laser-plasma interaction is critical to reproduce experimental measurements, but the interface between experiments and simulations can be challenging. Similarly, start-to-end simulations with different codes may require error-prone manipulations to convert between different representations of a laser pulse. [...]

Plasma wakefield acceleration using an electron filament offers stable, high-gradient, high-quality acceleration of positron beams analogous to the acceleration of electrons in the blowout regime. However, low energy-transfer efficiency is currently a limiting factor for future collider applications. [...]