U.S. Particle Accelerator School

Fourth Generation Light Sources I : X-Ray Laser course

Sponsoring University:

Indiana University


Fourth Generation Light Sources I : X-Ray Laser


Sven Reiche and Alex Murokh, UCLA

The future of synchrotron radiation sources is defined by a variety of new developments underway to reach, so far unattainable, photon beam characteristics. During the past 15 years much effort was dedicated to minimize the electron beam emittance leading to third generation light sources. Fourth generation light sources seem to be dominated by the desire to produce femtosecond x-ray pulses. Specifically, two concepts are under study and development to reach high-brightness x-rays. Both concepts are the content of a one-week course each. This course concentrates on the X-Ray Laser facility based on the SASE principle to be followed, next week, by another storage ring based approach. The physics and technology involved together with challenges will be introduced to provide a broad overview of the whole facility. The courses are focused primarily towards scientists, students, engineers and technicians, who are interested in participating in these developments.

Lectures will cover the operating principle of a single-pass high-gain Free-Electron Laser, closely following LCLS, the proposed X-ray FEL at SLAC. Besides the introduction to the general analytical model of an FEL, the focus is on the generation of a high-brightness beam driving the FEL. The content of the lecture is: FEL - motion in an undulator; interaction with a radiation field; 1D FEL model; diffraction and emittance effects (3D-model); self-amplification of spontaneous emission (SASE FEL). LCLS - RF-photo guns and emittance compensation; bunch compression; CSR and microbunch instabilities in a magnetic chicane; wakefields in linac and undulator. The students will work with various simulation tools (e.g. ELEGANT, PARMELA, GENESIS 1.3) using predefined input decks. The influence of certain key parameters (e.g. emittance) on the performances of the FEL, rf gun and linac will be studied. Prerequisites: Basic knowledge of accelerator physics, electrodynamics and Hamilton mechanics.