At the KIT Synchrotron KARA several systems are in place to measure and interact with individual electron bunches. A Bunch-by-Bunch (BBB) feedback system provides capabilities to control individual bunch motion whereas KAPTURE allows to readout multiple synchrotron radiation detector channels on the bunch-by-bunch level. This allows to closely study coherent radiation effects in our short...
Like many other subsystems in particle accelerators, the optical synchronization system at the European XFEL implements a joint high-performance control task over individual stations along the spatial extend of the facility. In the case of the optical synchronization system, this ensures a stable timing reference in the region of a few femtoseconds over more than 3.5km distance. Using...
For pump-probe experiments at free electron lasers, like the European XFEL,
a femtosecond precise bunch arrival time stability is mandatory. The
longitudinal intra bunch-train feedback (L-IBFB) system regulates the
arrival time, measured by a bunch arrival time monitor (BAM), with
femtosecond resolution. Due to the energy dependent path length of the
electron bunches through a...
FLUTE (Ferninfrarot Linac- und Test-Experiment) is a compact linac-based test facility for accelerator R&D and source of intense THz radiation for photon science. In preparation for the next experiments, the electron beam of the injector section of FLUTE has been characterized. In systematic studies the electron beam parameters, e.g., beam charge and emittance, are measured with several...
Multi-alkali antimonide-based photocathodes are suitable candidates for the electron sources of next-generation high brightness RF photoinjectors due to their excellent photoemissive properties, especially low thermal emittances, and high sensitivity to visible light. The utilization of these photocathodes is so far successfully demonstrated in low field DC gun-based photoinjectors. However,...
The ARES linac at DESY aims at producing and characterizing ultrashort electron bunches for cutting-edge applications (e.g. advanced and compact longitudinal diagnostics development, advanced and compact accelerating structures test, FLASH radiotherapy, etc.). The targeted properties (100-150 MeV, down to sub-pC charge and sub-fs duration) make the characterization of the bunch duration a...
Modeling of large-scale research facilities is extremely challenging due to complex physical pro-
cesses and engineering problems. We adopt a data-driven approach to model the longitudinal
phase-space diagnostic beamline at the photoinector of the European XFEL with an encoder-decoder
neural network model. We demonstrate that the model trained only with experimental data can make...
Within the scope of the Helmholtz AI Autonomous Accelerator Project machine learning methods for automating the accelerator operation are investigated. The recurrent task of manipulating the transverse beam parameters in the ARES experimental area poses as a test bed for studying reinforcement learning applications helping to automate complex tasks during accelerator operation. In this talk...
For future installations, new and powerful hardware components are required. In this talk, an 8-channel low-latency RF-digitizer, a distributed motion controller card and a RTM Class D1.3 digital processing board targeting serial JESD204 ADCs will be presented. All these boards are designed on the basis of ARM-based MPSoCs, which allow convenient board bring-up, configuration and...
To serve the diverse community at the ARD-ST 3 workshop, this presentation first introduces some key concepts of longitudinal beam dynamics before discussing the longitudinal beam dynamics at cSTART.
The compact STorage ring for Accelerator Research and Technology (cSTART) project aims to store electron bunches of laser-wakefield accelerator-like beams in a very large momentum acceptance...
During the operation of an electron synchrotron with short electron bunches the beam dynamics are influenced by the occurrence of the micro-bunching instability. This collective instability is caused by the self-interaction of a short electron bunch with its own emitted coherent synchrotron radiation (CSR). Above a certain threshold bunch current dynamic micro-structures start to occur on the...
New operation modes are often considered during the development of new synchrotron light sources. An understanding of the effects involved is inevitable for a successful operation of these schemes. At the KIT storage ring KARA (Karlsruhe Research Accelerator), new mode scan be implemented and tested at various energies, employing a variety of performant beam diagnostics devices. Negative...
Due to the exotic shape of the longitudinal phase space of electron bunches in
free-electron lasers, it is challenging to efficiently simulate their dynamics
using Vlasov methods. We present SeLaV1D, a semi-lagrangian Vlasov solver which
addresses this challenge by employing tree-based domain decomposition, and its
application to the analysis of the microbunching instability in...
Status update of the ARES construction works and results from beam commissioning.
Ultrafast Electron Diffraction (UED) is a technique used to observe dynamical changes in the structure of materials. It consists of a pump-probe scheme in which a laser pulse excites the target structure and a subsequent electron bunch scatters in the sample producing a diffraction pattern. The time resolution of MeV UED experiments is mainly governed by the electron bunch length and the time...
Slice energy spread is one of the key parameters of beam brightness for free electron laser optimizations, but its measurement is not straightforward. Two recent studies at high energy (>100 MeV) photoinjectors at SwissFEL and European XFEL have measured much higher slice energy spread than simulations, leading to the debate of necessity of laser heaters. In this report, we will show a new...
Intra-train bunch charge at FLASH shows an RMS of approx. 2 pC at 0.4 nC, with periodic oscillation that originates from within an injection laser cavity. Noticeable adverse effects on the final SASE were reported recently. The implementation of a slow and fast intra-train charge feedback is discussed. The measurement results show sub-pC charge flatness with the feed-back activated.
At the KIT storage ring KARA (KArlsruhe Research Accelerator) it is
planned to install an impedance manipulation structure in a versatile chamber
to study and eventually control the in
uence of an additional impedance on
the beam dynamics and the emitted coherent synchrotron radiation. For this
purpose the impedance of a corrugated pipe is under investigation. In this contribution,
we...
The Split Ring Resonator is a novel tool for longitudinal beam diagnostics of short bunches. The small metal device is a THz-driven resonator which creates a strong, vertical oscillating electro-magnetic field. This allows a time dependent streaking of an electron bunch with a frequency of around 300 GHz. The device is being installed and tested in FLUTE at KIT. The vertical streaking combined...
At the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany, a prototype cryomodule (Advanced Demonstrator) for the superconducting (SC) continuous wave (CW) Helmholtz Linear Accelerator (HELIAC) is under construction.
A transport line, comprising quadrupole lenses, rebuncher cavities, beam steerers and sufficient beam instrumentation has been built to deliver the beam from the...
The SRF linac-based Radiation Source ELBE operates with picosecond and sub-picosecond bunch length. The accelerator system provides beam in CW mode for two (FIR and MIR) FEL oscillators or for two THz sources comprising a superradiant undulator and coherent diffraction radiation (CDR) source. Performances of these sources depend critically on the bunch length. Single shot bunch length...
During accelerator operation, quadrupole gradients can be different from the set values for a variety of reasons.
Precise knowledge of quadrupole gradient errors is desirable in order to improve the optics with respect to the model.
The measured orbit matrix response encodes the optics of the lattice and hence can be used for inverse modeling of quadrupole gradients. The thus derived...
A very common bottleneck to study short electron bunch dynamics in accelerators is a detection scheme that can deal with high repetition rates in the MHz range. The KIT electron storage ring KARA (Karlsruhe Research Accelerator) is the first storage ring with a near-field single-shot electro-optical (EO) bunch profile monitor installed for the measurement of electron bunch dynamics in the...
Fundamentally, synchrotron radiation contains information about the particle distribution in the bunch. From this, among other things, the charge, length, shape and arrival time of the bunch can be determined. However, bunch lengths in the lower picosecond range were too short for conventional, commercial electronics in the past. In this talk, we will provide a glimpse of our recent...
Ultra-short pulses in the picosecond range, combined with the high repetition rate, high power and high brilliance at accelerator facilities opens a wide range possibilities for both fundamental as well as application-oriented research. Radiation generated at Free Electron Lasers (FELs) and Coherent Synchrotron Radiation (CSR) can be used for atomic and sub-atomic level studies. A frequent...
Emerging applications of X-ray free-electron lasers would benefit from femtosecond (fs) pulse durations and fs timing accuracies. The latter requires synchronization that can simultaneously lock all components with a precision better than the accelerator pulse duration. Large-scale facilities are usually synchronized using an RF reference clock and electronic phase-locking techniques. With...
A compact, longitudinal diagnostics for fs-scale electron bunches using a THz electric-field transient in a split-ring resonator (SRR) for streaking will be tested at the Far Infrared Linac and Test Experiment (FLUTE). We present the most important measures that have been carried out in the course of the preparations for the experiment: These include, first, the redesign of the laser optics at...
cSTART (compact Storage ring for Accelerator Research and technology) is a future project at KIT to demonstrate and examine the injection of ultra-short electron bunches and the storage of a laser wakefield accelerated (LWFA) like beam in a very large acceptance compact storage ring (VLA-cSR). Several parameters of the machine and the beam impose some challenges on the beam diagnostics at...
The task of the Particle Detector Combination detectors is to measure the beam intensity of slowly extracted ion beams. The complete range of possible beam intensities at FAIR cannot be covered by single detector type. At GSI this task is accomplished by a combination of three detectors, a plastic SCintillator (SC), an Ionization Chamber (IC) and a Secondary Electron Monitor (SEM).
The SEM...
For the European XFEL it was decided to use scintillator screens, as the standard diagnostics based on optical transition radiation (OTR) would undergo coherent effects at the machine. LYSO:Ce was chosen as scintillator material. However significantly larger emittances have been measured during the comissioning of the XFEL. Moreover there were measured "smoke-ring" distributions [*] at high...
Echo-Enabled Harmonic Generation (EEHG) is an external seeding technique for Free Electron Lasers (FEL). The technique implies complex transformations of the electron beam phase space. The transformations include laser-induced energy modulations and subsequent shearing of the modulations with dispersive chicanes. The goal of the transformations is to have the electron beam pre-bunched at a...
