FEL-Oscillator Simulations with Genesis 1.3

Modeling free-electron laser (FEL) oscillators requires calculation of both the light-beam interaction within the undulator and the propagation of the light outside the undulator. We present a paraxial Optical Propagation Code (OPC) based on the Spectral Method and Fresnel Diffraction Integral, which in combination with Genesis 1.3 can be used to perform either steady-state or time-dependent FEL oscillator simulations. A flexible scripting interface is used both to describe the optical resonator and to control the codes for propagation and amplification. OPC enables modeling of complex resonator designs that may include hard-edge elements (apertures) or hole-coupled mirrors with arbitrary\ud shapes. Some capabilities of OPC are illustrated using the FELIX system as an example

Developments of the TEUFEL injector racetrack microtron

In this paper we report on developments of the 25 MeV racetrack microtron (RTM) that will be the electron source for the second phase of the TEUFEL project, to generate radiation of 10 µm in a 2.5 cm period hybrid undulator. The theoretical understanding of this unconventional, azimuthally varying field type of RTM has been extended. A comparison of analytically calculated orbit stability with that based on measured data will be presented; orbit calculations using measured field data show the designed performance. Construction and tuning of the 1300 MHz, 2.2 MV microwave cavity have been completed, and signal level measurements have been performed. The overall assembly of the microtron is nearing completion. At present a vacuum pressure better than 5 × 10-7 Torr is achieved

Status of the "TEU-FEL" project

The free-electron laser of the TEU-FEL project will be realized in two phases. In phase I the FEL will be driven by a 6 MeV photoelectric linac. In phase II the linac will be used as an injector for a 25 MeV race-track microtron. Information is presented on some technical details and the status of the different subsystems

The "TEU-FEL" project

The free-electron laser of the TEU-FEL project will be based on a 6 MeV photo-cathode linac as injector, a 25 MeV race-track microtron as main accelerator and a hybrid, 25 mm period undulator. The project will be carried out in two phases. In phase one only the 6 MeV linac will be used, The FEL will then produce tunable radiation around 200 µm. In phase two the linac will be used as an injector for the microtron. The FEL will then produce tunable radiation around 10 µm. Technical information will be presented on the different subsystems

Design of a Double Focusing Beam Transport System for the 25 MeV Electron Beam

At the University of Twente in collaboration with the Technical University of Eindhoven a Free Electron Laser is being realised with a set-up of two accelerators. The injector is a 6 MeV photo cathode linac producing a high brightness beam. The second accelerator is a Race-Track-Microtron. For the Free Electron Laser project TUEFEL fase II a system was designed to transport the electron beam with an energy of 25 MeV from the racetrack microtron to the undulator. The constructive features of the undulator and resonator demand a detailed matching between electron beam and undulator. The relative small length of the resonator requires a compact injection part of the transport system. Matching of the electron beam is performed in two steps general fixed focusing is done with quadrupoles in a dispersive section. Fine tuned focusing is done in the dispersion free part of the transport line. Dynamic 3-D simulations with space charge were done to obtain the design parameters of the beam transport system. Optimal matching of the electron beam at the undulator’s entrance is obtained

Vrije-Elektronen-Laser werk aan de Universiteit van Twente in samenwerking met het Nederlands Centrum voor Laser Research

In de vakgroep Quantum Elektronica van de Faculteit Technische Natuurkunde aan de Universiteit Twente zijn momenteel drie Vrije-Elektronen-Laser projecten operationeel. De projecten worden uitgevoerd in nauwe samenwerking met het Nederlands Centrum voor Laser Research. Het FEL-onderzoek binnen de vakgroep richt zich met name op de fysische aspecten van het FEL-mechanisme en de technologische ontwikkeling van componenten voor een effectieve produktie van straling. Ook wordt veel aandacht besteed aan de ontwikkeling van diagnostiek, zowel voor de elektronenbundel als voor de optische bundel. Veel componenten zijn in huis ontwikkeld en gebouwd. Op deze wijze wordt getracht FEL’s aantrekkelijk te maken voor industriële toepassingen. Dit laatste aspect krijgt met name veel aandacht in de samenwerking met het NCLR. Hieronder volgt een korte beschrijving van de verschillende projecten

A quantitative theory-versus-experiment comparison for the intense laser dissociation of H2+

A detailed theory-versus-experiment comparison is worked out for H$_2^+$ intense laser dissociation, based on angularly resolved photodissociation spectra recently recorded in H.Figger's group. As opposite to other experimental setups, it is an electric discharge (and not an optical excitation) that prepares the molecular ion, with the advantage for the theoretical approach, to neglect without lost of accuracy, the otherwise important ionization-dissociation competition. Abel transformation relates the dissociation probability starting from a single ro-vibrational state, to the probability of observing a hydrogen atom at a given pixel of the detector plate. Some statistics on initial ro-vibrational distributions, together with a spatial averaging over laser focus area, lead to photofragments kinetic spectra, with well separated peaks attributed to single vibrational levels. An excellent theory-versus-experiment agreement is reached not only for the kinetic spectra, but also for the angular distributions of fragments originating from two different vibrational levels resulting into more or less alignment. Some characteristic features can be interpreted in terms of basic mechanisms such as bond softening or vibrational trapping.Comment: submitted to PRA on 21.05.200