Auslegung des Laserstrahltransports und Charakterisierung des Photoinjektorlasers an FLUTE = Design of the Laser Transport System and Characterization of the Photoinjector Laser at FLUTE

Das Ferninfrarot Linac- und Testexperiment (FLUTE) wird zur Zeit am KIT aufgebaut. Ein Hauptziel des Linearbeschleunigers ist es ultra-kurze (< 10 fs) Elektronenpakete zur Generierung von THz-Strahlung zu erzeugen. Die Elektronenpakete werden durch den photoelektrischen Effekt, bei dem UV Laserpulse auf eine Kupferkathode treffen, ausgelöst. Die Qualität des Laserspots ist dabei maßgebend für die erreichbare Qualität des Elektronenpaktes und wird durch eine Transportoptik vorgegeben. Für den Transport des Laserstrahls vom Laserlabor bis zur Kathode über ca. 30 m, wurde im Rahmen der vorliegenden Arbeit über ein Raytracing-Programm die Transportoptik für sowohl die normalen Betriebsmodi als auch für den Extremfall des Split Ring Resonator (SRR)-Experimentes simuliert und ausgelegt. Zur weiteren Optimierung werden die tatsächlichen Strahlparameter des Laserstrahls benötigt, da diese einen großen Einfluss auf die Auslegung des Transportsystems und somit auf die Qualität der Elektronenpakete haben. Im zweiten Teil dieser Arbeit wurde für die Messung dieser Parameter ein sogenanntes Knife-Edge Experiment aufgebaut und konnte erfolgreich an einem sichtbaren Justierlaser getestet werden. Die Messung wurde anschließend am FLUTE Lasersystem aufgebaut und angepasst, so dass eine Messmethode zur Verfügung steht, mit der die Parameter der verbleibenden Laserausgänge bestimmt werden können.

Systematic Beam Parameter Studies at the Injector Section of FLUTE

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 energy and emittance, are measured with several diagnostic systems. This knowledge allows the establishment of different operation settings and the optimization of electron beam parameters for future experiments

Split-ring resonator experiments and data analysis at FLUTE

FLUTE (Ferninfrarot Linac- Und Test-Experiment) is a compact linac-based test facility for accelerator and diagnostics R&D located at the Karlsruher Institute of Technology (KIT). A new accelerator diagnostics tool, called the split-ring resonator (SRR), was tested at FLUTE, which aims at measuring the longitudinal bunch profile of fs-scale electron bunches. Laser-generated THz radiation is used to excite a high frequency oscillating electromagnetic field in the SRR. Electrons passing through the 20 µm x 20 µm SRR gap are time-dependently deflected in the vertical plane, leading to a vertical streaking of the electron bunch. During the commissioning of the SRR at FLUTE, large series of streaking attempts with varying machine parameters and set-ups were investigated in an automatized way. The recorded beam screen images during this experiment have been analyzed and evaluated. This contribution motivates and presents the automatized experiment and discusses the data analysis

Prospects for photon science and beam dynamics studies of a THz undulator at FLUTE

n recent years the interest in high intensity, short-pulse coherent THz radiation for non-linear experimental research and applications grew with upcoming high intensity lasers. In contrast to lasers, accelerators provide free electrons for which emission properties can be tailored to the demand at typically much higher repetition rates than high-intensity lasers can provide. Efforts are ongoing to augment short-bunch accelerators such as the European XFEL with THz radiation sources such as undulators. At the far-infrared linac and test experiment (FLUTE) at KIT, we can facil- itate experiments to investigate coherent THz radiation from different sources and provide short electron bunches. As an additional THz source, a superconducting undulator can be inserted and investigated. In this contribution, we evaluate the opportunities of this THz undulator at FLUTE for linear accelerators and FELs in terms of photon science and beam dynamics

Efficient Terahertz Generation by Tilted-Pulse-Front Pumping in Lithium Niobate for the Split-Ring Resonator Experiment at FLUTE

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 Ferninfrarot Linac- Und Test- Experiment (FLUTE). For this new streaking technique, intensive THz pulses are required, which will be generated by laser-based optical rectification. We present a setup for generating THz pulses using tilted-pulse-front pumping in lithium niobate at room temperature. Excited by an 800 nm Ti:Sa pump laser with 35 fs bandwidth-limited pulse length, conversion efficiencies up to 0.027% were achieved. Furthermore, the status of the SRR experiment is shown

Commissioning Status of FLUTE

FLUTE (Ferninfrarot Linac- Und Test-Experiment) will be a new compact versatile linear accelerator at the KIT. Its primary goal is to serve as a platform for a variety of accelerator studies as well as to generate strong ultra-short THz pulses for photon science. The phase I of the project, which includes the RF photo injector providing electrons at beam energy of 7 MeV and a corresponding diagnostics section, is currently being commissioned. In this contribution, we report on the latest progress of the commissioning phase. The status of the gun conditioning will be given, followed by an overview of the RF system and the laser system