Coherent, high repetition rate tender x-ray free-electron laser seeded by an extreme ultra-violet free-electron laser oscillator

Abstract

A seeded FEL driven by a linac based on super conducting cavities, generating 108–1010 coherent photons per shot at 2–5 keV with 0.2–1 MHz of repetition rate, can address the need of a source devoted to fine analysis of matter using the linear spectroscopy technique. The seeding scheme described hereafter is a multi-stage cascade upshifting the radiation frequency by a factor 20–40. The x-ray range can be achieved with a seed constituted by a coherent flash in the extreme ultraviolet range provided by an FEL oscillator operating at 12–14 nm. The whole chain of x-ray generation is described by means of start-to-end three-dimensional simulations.

Two-Color TeraHertz Radiation by a Multi-Pass FEL Oscillator

“…Furthermore, the values of the macroscopic electron beam parameters, such as energy, current, emittance, and energy spread, have been varied to reproduce the shot-to-shot jitters. Each radiation output result is obtained by maximizing the output power as a function of the delay time compensating the slippage, and cycling the radiation within the cavity, taking into account the details of the optical line that returns the radiation to the undulator entrance [19,20]. Mirror reflectivities of the order of 95-97% have been assumed.…”

Three-Dimensional, Time-Dependent Analysis of High- and Low-Q Free-Electron Laser Oscillators

“…The development of both low-gain/high-Q and high-gain/low-Q oscillators is an active and ongoing area of research into FEL sources over virtually the entire electromagnetic spectrum [30,86,91,92,241,[244][245][246][247][248]. Both types of FEL oscillators have their own merits.…”

Features and futures of X-ray free-electron lasers

“…Extreme UV FEL oscillators driven by 2–2.6 GeV electron beams have been proposed as a seeding source for a triple cascade, thereby generating few Ångstrom-class radiation. 145 As the energy spread is large when the FEL oscillator is saturated, multi-bunch operation is needed for this scheme to achieve a high peak power. Recently, a resonator-like seed recirculation feedback system was proposed in which the radiation in the cavity is recirculated to modulate following bunches but is far from saturation.…”