Dresden 2014 – wissenschaftliches Programm

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BE: Beschleunigerphysik

BE 15: Beam Dynamics and Fields III

BE 15.6: Gruppenbericht

Donnerstag, 3. April 2014, 16:45–17:15, ZEU 255

Short-pulse studies at FLASH — •Marie Rehders — Universität Hamburg, for the short bunches project at FLASH

Many users at FLASH work on pump-probe experiments, where time resolution is determined by the FEL pulse duration. Therefore they have expressed a keen interest in being provided with shorter XUV pulses. The shortest possible SASE pulse is a single longitudinal optical mode of the FEL radiation, resulting in radiation pulses of some 3 fs.

The most direct way to realize this at FLASH would be to reduce the electron bunch length to only a few μm at the entrance of the undulator section. The maximum tolerable bunch compression from the cathode to the FEL is limited to a factor of approximately 300 due to beam dynamics issues and RF tolerances. Thus, the bunch duration at the injector has to be as short as approximately 1ps, which in turn calls for low bunch charges to make space charge effects tolerable. A new photo-injector laser with adjustable pulse duration is thus used to optimize the initial bunch length at the cathode.

Beam dynamic studies are performed to optimize the injection and compression of low charge electron bunches, starting with the pulse parameters of the injector laser. Also, first experimental results with several injector laser settings are compared with beam dynamic simulations and presented in this contribution.