High Repetition Rate and Coherent Free-Electron Laser in the X-Rays Range Tailored for Linear Spectroscopy
oleh: Vittoria Petrillo, Michele Opromolla, Alberto Bacci, Illya Drebot, Giacomo Ghiringhelli, Alberto Petralia, Ezio Puppin, Marcello Rossetti Conti, Andrea Renato Rossi, Alberto Tagliaferri, Sanae Samsam, Luca Serafini, Giorgio Rossi
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2019-09-01 |
Deskripsi
Fine time-resolved analysis of matter—i.e., spectroscopy and photon scattering—in the linear response regime requires fs-scale pulsed, high repetition rate, fully coherent X-ray sources. A seeded Free Electron Laser (FEL) driven by a Linac based on Super Conducting cavities, generating <inline-formula> <math display="inline"> <semantics> <msup> <mn>10</mn> <mn>8</mn> </msup> </semantics> </math> </inline-formula>−<inline-formula> <math display="inline"> <semantics> <msup> <mn>10</mn> <mn>10</mn> </msup> </semantics> </math> </inline-formula> coherent photons at 2−5 keV with 0.2−1 MHz of repetition rate, can address this need. Three different seeding schemes, reaching the X-ray range, are described hereafter. The first two are multi-stage cascades upshifting the radiation frequency by a factor of 10−30 starting from a seed represented by a coherent flash of extreme ultraviolet light. This radiation can be provided either by the High Harmonic Generation of an optical laser or by an FEL Oscillator operating at 12−14 nm. The third scheme is a regenerative amplifier working with X-ray mirrors. The whole chain of the X-ray generation is here described by means of start-to-end simulations.