Large Bandwidth X-ray ; Accelerator Physics; Free Electron Laser
Guetg Marc, Beutner Bolko, Prat Eduard, Reiche Sven (2013), Dispersion Based Beam Tilt Correction
, JaCow, Switzerland (CERN).
Guetg Marc, Optimization of free electron laser performance by dispersion-based beam-tilt correction, in Phys. Rev. STAB
, 18, 030701-1-030701-10.
In this proposal the design study for a large-bandwidth mode of operation of the hard X-ray beamline Aramis at the SwissFEL facility is proposed. It is the central part of a Ph.D. thesis in accelerator physics.This mode of operation allows for single shot spectroscopic and crystallographic measurements of time-resolved processes such as photo-induced chemical reactions in liquids or on surfaces and biochemical processes in protein crystals. To measure these structural changes, subtle differences in the spectral absorption or the Laue diffraction pattern need to be measured, which is under normal operation (non large bandwidth mode) obscured by shot-shot fluctuations of the Self-amplifying spontaneous emission (SASE) Free-electron Laser (FEL), which occur while scanning over the desired spectral range. A special large-bandwidth mode of operation can be achieved by accumulating wakefields in the main SwissFEL linac, after the electron bunch has been over-compressed in the last bunch compressor. It requires additional correction and diagnostic elements to compensate degrading effects such as the beam distortion from coherent synchrotron radiation in bending magnets.Designing and instrumentation of SwissFEL for this purpose would provide a unique mode of operation with significant interest for users, which cannot be provided by other X-ray FELs worldwide.