A5005958078- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Gyrotron and Vacuum Electronics Research
- Advanced X-ray Imaging Techniques
- Electromagnetic Simulation and Numerical Methods
- Superconducting Materials and Applications
- Electromagnetic Scattering and Analysis
- X-ray Spectroscopy and Fluorescence Analysis
- Particle Detector Development and Performance
- Lightning and Electromagnetic Phenomena
- Enzyme Structure and Function
- Advanced Electron Microscopy Techniques and Applications
- Crystallography and Radiation Phenomena
- Microwave Engineering and Waveguides
- Photocathodes and Microchannel Plates
- Advanced Numerical Methods in Computational Mathematics
- Distributed and Parallel Computing Systems
- Advancements in Photolithography Techniques
- Scientific Research and Discoveries
- Laser-Plasma Interactions and Diagnostics
- Differential Equations and Numerical Methods
- Engineering Applied Research
- Numerical methods in inverse problems
- Electromagnetic Compatibility and Noise Suppression
- Internet of Things and Social Network Interactions
Deutsches Elektronen-Synchrotron DESY
2014-2024
Universität Hamburg
2017-2019
SLAC National Accelerator Laboratory
2007-2016
Menlo School
2007-2016
Stanford University
2011
Hamburg Institut (Germany)
2007
Technical University of Darmstadt
2002-2005
Lomonosov Moscow State University
2002
X-ray pump/X-ray probe applications are made possible at Free Electron Laser (XFEL) facilities by generating two pulses with different wavelengths and controllable temporal delay. In order to enable this capability the European XFEL, an upgrade project equip soft SASE3 beamline a magnetic chicane is underway. present paper we describe status of project, its scientific focus expected performance, including start-to-end simulations photon beam transport up sample, as well recent experimental...
Abstract A conformal finite‐difference time‐domain algorithm for the solution of electrodynamic problems in general perfectly conducting 3D geometries is presented. Unlike previous approaches it has second‐order convergence without need to reduce maximal stable time step conventional staircase approach. novel proof local error rate given, and method verified compared other by means several numerical 2D examples. Copyright © 2003 John Wiley & Sons, Ltd.
The Yee finite-difference time domain method (FDTD) is commonly used in wake field and particle-in-cell simulations. However, accelerator modeling the high energy particles can travel vacuum faster than their own radiation. This effect referred to as numerical Cherenkov radiation a consequence of grid dispersion. Several approaches are proposed reduce dispersion for all angles given frequency range, that justifies itself domains big three directions. On contrary, transverse dimensions beam...
The Single Particles, Clusters and Biomolecules & Serial Femtosecond Crystallography (SPB/SFX) instrument at the European XFEL is located behind SASE1 undulator aims to support imaging structure determination of biological specimen between about 0.1 μm 1 size. designed work photon energies from 3 keV up 16 keV. Here, we propose a cost-effective proof-of-principle experiment, aiming demonstrate actual feasibility single molecule diffraction experiment XFEL. To this end, assume...
Temporally modulated electron beams have a wide array of applications ranging from the generation coherently enhanced electromagnetic radiation to resonant excitation wakefields in advanced-accelerator concepts. Likewise producing low-energy ultrashort microbunches could be useful for ultrafast diffraction and new accelerator-based light-source In this Letter we propose experimentally demonstrate passive microbunching technique capable forming picosecond bunch train at...
In this paper we introduce an analytical solution (up to the third order) for a multistage bunch compression and acceleration system without collective effects. The with effects is found by iterative procedure based on result. developed formalism applied FLASH facility at DESY. Analytical estimations of RF tolerances are given.
The output power of a free electron laser (FEL) has extremely high variance even when all FEL parameter set points are held constant because the stochastic nature self-amplified spontaneous emission (SASE) process, drift thousands coupled parameters, such as thermal drifts, and uncertainty time variation distribution coming off photo cathode entering accelerator. In this work, we demonstrate application automatic, model-independent feedback for maximization average pulse energy light...
We develop analytical models of the longitudinal and transverse wakes, on off axis for a flat, corrugated beam pipe with realistic parameters, then compare them numerical calculations, generally find good agreement. These ``first order'' formulas approximate droop at origin wake slope wakes; they represent an improvement in accuracy over earlier, ``zeroth formulas. In example calculations RadiaBeam/LCLS dechirper using typical we 16% energy chirp bunch tail compared to simpler calculations....
This document provides detailed information on the status of Advanced and Novel Accelerators techniques describes steps that need to be envisaged for their implementation in future accelerators, particular high energy physics applications. It complements overview prepared update European Strategy particle physics, a description field. The scientific priorities community are described each technique acceleration able achieve accelerating gradient GeV~range or above. ALEGRO working group...
We consider the calculation of electromagnetic fields generated by an electron bunch passing through a vacuum chamber structure that, in general, consists entry pipe, followed some kind transition or cavity, and ending exit pipe. limit our study to structures having rectangular cross section, where height can vary as function longitudinal coordinate but width side walls remain fixed. For such structures, we derive Fourier representation wake potentials one-dimensional functions. A new...
Abstract We propose to develop, characterize and operate a superconducting undulator (SCU) afterburner consisting of 5 modules (1 module = 2 SCU coils m length 1 phase shifter) plus pre-series prototype at the SASE2 hard X-ray beamline European XFEL. This will produce an output in order 10 ph/pulse photon energies above 30 keV. The project is divided into production small-series modules. Central goals this R&D activity are: demonstration functionality SCUs FEL, set up needed...
The development of the modern accelerator and free-electron laser projects requires to consider wake fields very short bunches in arbitrary three dimensional structures. To obtain numerically by direct integration is difficult, since it takes a long time for scattered catch up bunch. On other hand no general algorithm indirect field available literature so far. In this paper we review known methods compute potentials rotationally symmetric cavity-like For geometries introduce several new...
In this paper we introduce an optical approximation into the theory of impedance calculation, one valid in limit high frequencies. This neglects diffraction effects radiation process, and is conceptually equivalent to geometric optics electromagnetic theory. Using approximation, derive equations for longitudinal arbitrary offsets, with respect a reference orbit, source test particles. With help Panofsky-Wenzel theorem, also obtain expressions transverse (also offsets). We further simplify...
We consider the collective beam dynamics in accelerator of European X-ray Free Electron Laser for electron bunches with charges 250 and 500 pC. The has been studied numerically different computer programs, we struggle to include properly whole physics effects. Several scenarios longitudinal are considered peak currents 5 10 kA. A procedure choice machine parameters is described, tolerances radio frequency accelerating modules along calculated. bunch properties at end before undulator line...
For more than 5 years, superconducting undulators (SCUs) have been successfully delivering X-rays in storage rings. The European X-Ray Free-Electron Laser Facility (XFEL) plans to demonstrate the operation of SCUs X-ray free-electron lasers (FELs). same geometry, can reach a higher peak field on axis with respect all other available technologies, offering larger photon energy tunability range. application short-period high electron beam FEL > 11 GeV will enable lasing at very hard 40...
Undulator tapering controls the resonance properties of free-electron laser (FEL) amplification process. Wakefield energy losses in an undulator’s vacuum chamber are one factors that determine linear taper. While another contribution to losses, namely due spontaneous radiation, can be calculated analytically, estimating wakefield requires detailed knowledge geometry and electron beam current profile. We introduce a method for automatic estimation which leverages noninvasive THz diagnostics,...
We report on a recent set of measurements the transverse wakefields from longitudinally tapered collimators. The were performed with low-emittance 1.19 GeV beam in SLAC linac by inserting collimator aperture into path and reconstructing vertical deflection as function position aperture. Each experiment was designed to present relatively large impedance minimize other contributions such resistivity. In addition, parameters chosen provide some insight scaling geometric wakefield collimator's...
For modern linac- and storage-ring-based light sources certain amount of empirical tuning is used to reach ultimate performance. The possibility perform such by automatic methods has now been demonstrated several authors (e.g. I.Agapov et al. in proc IPAC 2015). In this paper we present the progress development our optimisation software based on OCELOT its applications SASE FEL optimization at FLASH LCLS, potential for storage ring optimization.
In a companion report, we have derived method for finding the impedance at high frequencies of vacuum chamber transitions that are short compared to catch-up distance, in frequency regime that---in analogy geometric optics light---we call optical regime. this report apply various nonaxisymmetric geometries such as irises/short collimators beam pipe, step-in transitions, step-out and more complicated practical importance. Most our results analytical, with few given terms simple...
We consider a 3D electron bunch at the cathode, modelled via photoemission, with realistic (asymmetric) spatial and temporal distributions for accelerator beam dynamics studies European X-ray Free-Electron Laser (European XFEL). A series of measurements are performed low energy beams in XFEL injector. Using modeled bunches, simulations, enabled by three-dimensional (3D) space-charge solver valid image-charge calculation on photocathode plane, have shown improved agreements measured...