40 research outputs found
High throughput data streaming of individual longitudinal electron bunch profiles in a storage ring with single-shot electro-optical sampling
The development of fast detection methods for comprehensive monitoring of
electron bunches is a prerequisite to gain comprehensive control over the
synchrontron emission in storage rings with their MHz repetition rate. Here, we
present a proof-of-principle experiment with at detailed description of our
implementation to detect the longitudinal electron bunch profiles via
single-shot, near-field electro-optical sampling at the Karlsruhe Research
Accelerator (KARA). Our experiment is equipped with an ultra-fast line array
camera providing a high-throughput MHz data stream. We characterize statistical
properties of the obtained data set and give a detailed description for the
data processing as well as for the calculation of the charge density profiles,
which where measured in the short-bunch operation mode of KARA. Finally, we
discuss properties of the bunch profile dynamics on a coarse-grained level on
the example of the well-known synchrotron oscillation.Comment: 8 pages, 5 figure
Design Considerations of the Corrugated Structures in a Vacuum Chamber for Impedance Studies at KARA
Fast Mapping of Terahertz Bursting Thresholds and Characteristics at Synchrotron Light Sources
Dedicated optics with extremely short electron bunches enable synchrotron
light sources to generate intense coherent THz radiation. The high degree of
spatial compression in this so-called low-alpha optics entails a complex
longitudinal dynamics of the electron bunches, which can be probed studying the
fluctuations in the emitted terahertz radiation caused by the micro-bunching
instability ("bursting"). This article presents a "quasi-instantaneous" method
for measuring the bursting characteristics by simultaneously collecting and
evaluating the information from all bunches in a multi-bunch fill, reducing the
measurement time from hours to seconds. This speed-up allows systematic studies
of the bursting characteristics for various accelerator settings within a
single fill of the machine, enabling a comprehensive comparison of the measured
bursting thresholds with theoretical predictions by the bunched-beam theory.
This paper introduces the method and presents first results obtained at the
ANKA synchrotron radiation facility.Comment: 7 pages, 7 figures, to be published in Physical Review Accelerators
and Beam
Simultaneous Detection of Longitudinal and Transverse Bunch Signals at a Storage Ring
To understand and control the dynamics in the longitudinal phase space,
time-resolved measurements of different bunch parameters are required. For a
reconstruction of this phase space, the detector systems have to be
synchronized. This reconstruction can be used e.g. for studies of the
micro-bunching instability. It occurs if the interaction of the bunch with its
own radiation leads to the formation of sub-structures on the longitudinal
bunch profile. These sub-structures can grow rapidly -- leading to a
sawtooth-like behaviour of the bunch. At KARA, we use a fast-gated intensified
camera for energy spread studies, Schottky diodes for coherent synchrotron
radiation studies as well as electro-optical spectral decoding for longitudinal
bunch profile measurements. For a synchronization, a hardware synchronization
scheme is used which compensates for eventual hardware delays. In this paper,
the different experimental setups and their synchronization are discussed and
first results of synchronous measurements are presented
Diagnostics of longitudinal bunch instabilities at KARA
KARA, the Karlsruhe Research Accelerator, can be operated in different modes, including a short-bunch mode. During this mode, where the dispersion is stretched in order to reduce the momentum-compaction factor, micro-bunching instability can occur. At KARA, several measurement setups and techniques are used to investigate this instability further with the long-term perspective to suppress and control it. In this contribution, we give an overview about the different setups and the results achieved during the past years
Electro-Optical Diagnostics at KARA and FLUTE – Results and Prospects
Electro-optical (EO) methods are nowadays well-proven diagnostic tools, which are utilized to detect THz fields in countless experiments. The world’s first near-field EO sampling monitor at an electron storage ring was developed and installed at the KIT storage ring KARA (Karlsruhe Research Accelerator) and optimized to detect longitudinal bunch profiles. This experiment with other diagnostic techniques builds a distributed, synchronized sensor network to gain comprehensive data about the phase-space of electron bunches as well as the produced coherent synchrotron radiation (CSR). These measurements facilitate studies of physical conditions to provide, at the end, intense and stable CSR in the THz range. At KIT, we also operate FLUTE (Ferninfrarot Linac- und Test-Experiment), a new compact versatile linear accelerator as a test facility for novel techniques and diagnostics. There, EO diagnostics will be implemented to open up possibilities to evaluate and compare new techniques for longitudinal bunch diagnostics. In this contribution, we will give an overview of results achieved, the current status of the EO diagnostic setups at KARA and FLUTE and discuss future prospects
Longitudinal Beam Dynamics and Coherent Synchrotron Radiation at cSTART
The compact STorage ring for Accelerator Research and Technology (cSTART) project aims to store electron bunches of LWFA-like beams in a very large momentum acceptance storage ring. The project will be realized at the Karlsruhe Institute of Technology (KIT, Germany). Initially, the Ferninfrarot Linac- Und Test-Experiment (FLUTE), a source of ultra-short bunches, will serve as an injector for cSTART to benchmark and emulate laser-wakefield accelerator-like beams. In a second stage a laser-plasma accelerator will be used as an injector, which is being developed as part of the ATHENA project in collaboration with DESY and Helmholtz Institute Jena (HIJ). With an energy of 50 MeV and damping times of several seconds, the electron beam does not reach equilibrium emittance. Furthermore, the critical frequency of synchrotron radiation is 50 THz and in the same order as the bunch spectrum, which implies that the entire bunch radiates coherently. We perform longitudinal particle tracking simulations to investigate the evolution of the bunch length and spectrum as well as the emitted coherent synchrotron radiation. Finally, different options for the RF system are discussed
Implementing Electro-Optical Diagnostics for Measuring the CSR far-field at KARA
For measuring the temporal profile of the coherent synchrotron radiation (CSR) at the KIT storage ring KARA (Karlsruhe Research Accelerator) an experimental setup based on electro-optical spectral decoding (EOSD) is currently being implemented. The EOSD technique allows single-shot, phase-sensitive measurements of the far-field radiation on a turn-by-turn basis at rates in the MHz range. Therefore, the resulting THz radiation from the dynamics of the bunch evolution, e.g. the microbunching, can be observed with high temporal resolution. This far-field setup is part of the distributed sensor network at KARA. Additionally to the information acquired from the near-field EOSD spectral decoding and the horizontal bunch profile monitor, it enables to monitor the longitudinal phase-space of the bunch. In this contribution, the characterization of the far-field setup is summarized and its implementation is discussed