Beam loss simulations for the implementation of the Hard X-Ray Self-Seeding system at European XFEL

8th International Particle Accelerator Conference

Liu, Shan^1 ; Decking, Winfried^1 ; Fröhlich, Lars^1

Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, Hamburg

22607, Germany^1

关键词: Beam energies;    Critical numbers;    Diamond crystals;    European xfel;    High repetition rate;    Operation mode;    Particle tracking;    Repetition rate;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/874/1/012022/pdf
DOI  :  10.1088/1742-6596/874/1/012022

来源: IOP

【 摘 要 】

The European XFEL is designed to be operated with a nominal beam energy of 17.5 GeV at a maximum repetition rate of 27000 bunches/second. The high repetition rate together with the high loss sensitivity of the undulators raises serious radiation damage concern, especially for the implementation of the Hard X-ray Self-Seeding (HXRSS) system, where a 100 μm thick diamond crystal will be inserted close to the beam in the undulator section. Since the seeding power level highly depends on the delay of the electron beam with respect to the photon beam, it is crucial to define the minimum electron beam offset to the edge of the crystal in the HXRSS chicane. At European XFEL a ∼200 m long post-linac collimation section has been designed to protect the undulators. In the HXRSS scheme, however, beam halo particles hitting the crystal can generate additional radiation. Particle tracking simulations have been performed using GEANT4 and BDSIM for the undulator and the collimation section, respectively. The critical number of electrons allowed to hit the crystal is estimated for a certain operation mode and the efficiency of beam halo collimation is investigated to predict the minimum HXRSS chicane delay.