44 research outputs found
Different Charges in the Same Bunch Train at the European XFEL
In this paper we have investigated the possibility of the operation of
different charges in the bunch train for the nominal design of the XFEL
injector and for the case that it is extended by an additional laser system on
the cathode. We have examined the problem of similarity of beam optical
functions for different bunch charges in a train. We report also about the
sensitivity of the beam optical functions on the chosen compression scenario
and give an overview over the working points for the settings at the injector
for single charge operation as well as combined working points for different
bunch pairs
European XFEL Post-TDR Description
This document lists and describes design changes of the European XFEL with respect to the technical design report (TDR), points out regions or components that are worked out and documented in much more detail than in the TDR, and provides an overview of possible upgrades that are presently being discussed. Includes the EDMS identifiers of detailed documents
Neue Optik zur Akzeptanz-Vergroesserung im PR-Weg mit einem Spiegelplatten-Quadrupolmagneten
Uncorrelated Emittance Growth in the TTF-FEL Bunch Compression Sections due to Coherent Synchrotron Radiation and Space Charge Effects
In the bunch compressing sections of the Tesla Test Facil-ity Free Electron Laser[1] (TTF FEL), short bunches travel on trajectories with small bending radii. Thus, coherent synchrotron radiation (CSR) will play a significant role in beam dynamics. The energy loss of the bunch will vary longitudinally as well as transversally across the bunch and will induce an emittance growth. The occuring transversal forces, especially the so-called “Talman force ” ([3]) and its effects on emittance have been treated before analytically for some specialized arrangements ([2, 4]). The emittance growth will affect the projective as well as the slice emittance (i.e., the emittance of sub-ensembles of particles with equal longitudinal position). The com-puter simulation code TraFiC4 calculates the fields in the bunch from first principles, thus taking into account radia-tive as well as space charge effects, which are inseparable on curved trajectories. In addition to dealing with longi-tudinal dynamics [5], this code has now been extended to handle the transversal dynamics of the bunch. We use it to study the behavior of the fields across the beam and the re-sulting slice and projective emittance growth. We study its dependence on bunch parameters such as charge and shape and investigate possible cures by shielding.
Corrugated Structure Insert to Extend SASE Bandwidth Up to 3% at the European XFEL
The usage of x-ray free electron laser (XFEL) in femtosecondnanocrystallography involves sequential illumination ofmany small crystals of arbitrary orientation. Hence a wideradiation bandwidth could be useful in order to obtain and toindex a larger number of Bragg peaks used for determinationof crystal orientation.Considering the baseline configuration of the EuropeanXFEL in Hamburg, and based on beam dynamics simulations,we demonstrate here that usage of corrugated structuresallows for a considerable increase in radiation bandwidth.It allows for data collection with a 3% bandwidth, afew micrjoule radiation pulse energy, a few fs pulse duration,and a photon energy 5.4 keV