Title :
Investigations of electron-beam microbunching and beam coalignment using CTR in a high-gain SASEe FEL
Author :
Lumpkin, A. ; Berg, W. ; Biedron, S. ; Borland, M. ; Chae, Y.-C. ; Dejus, R. ; Lewellen, J. ; Milton, S. ; Moog, E. ; Travish, G. ; Yang, B.
Author_Institution :
Adv. Photon Source, Argonne Nat. Lab., IL, USA
Abstract :
We recently extended our experiments on z-dependent electron-beam microbunching using coherent transition radiation (CTR) into the high-gain, self-amplified spontaneous emission free-electron laser (FEL) regime. The UV-visible FEL at the Advanced Photon Source was operated at 530 nm and 385 nm using the bunch-compressed photocathode gun electron beam, linac, and 21.6 m of undulator length. The longitudinal microbunching of the electron beam was tracked by inserting a metal foil and a mirror after each of the nine 2.4-m-long undulators. The visible CTR generated by the electron-beam interaction was imaged and analyzed for z-dependent intensity, angular distribution, and spot size. Additionally, the image centroids and structures were used in evaluating the critical electron beam/photon beam overlap issue as a complement to the trajectory data from the beam position monitors
Keywords :
free electron lasers; linear accelerators; particle beam bunching; particle beam diagnostics; 385 nm; 530 nm; Advanced Photon Source; UV-visible FEL; angular distribution; coherent transition radiation; electron beam coalignment; electron beam/photon beam overlap; electron-beam microbunching; high-gain SASE FEL; image centroids; longitudinal microbunching; spot size; Cathodes; Charge carrier processes; Electron beams; Free electron lasers; Laser beams; Laser transitions; Linear particle accelerator; Mirrors; Spontaneous emission; Undulators;
Conference_Titel :
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001
Conference_Location :
Chicago, IL
Print_ISBN :
0-7803-7191-7
DOI :
10.1109/PAC.2001.987566
