Dattoli, G.
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| MOPP014 | Status of the Seeding Experiment at SPARC | 63 |
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Funding: Work supported by the EU Commission in the sixth framework programme, contract no. 011935 – EUROFEL. Sources based on high order harmonics generated in gas with high power Ti:Sa lasers pulses represent promising candidates as seed for FEL amplifiers for several reasons, as spatial and temporal coherence, wavelength tunability and spectral range, which extends down to the 10(-9)m wavelength scale. This communication is devoted to the description of a research work plan that will be implemented at the SPARC FEL facility in the framework of the EUROFEL programme. The main goal of the collaboration is to study and test the amplification and the FEL harmonic generation process of an input seed signal obtained as higher order harmonics generated both in crystal (400nm and 266 nm) and in gas (266nm, 160nm, 114nm) from a high intensity Ti:Sa laser pulse. |
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| MOPP056 | Phase Shifters for the SPARC Undulator System | 187 |
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In the framework of the SPARC FEL experiment, a 14-m long undulator divided into six sections is presently under construction (by ACCEL Instruments GmbH). In order to correct the phase difference between the electron beam and the radiation, a tunable device will be inserted at the end of each of the six sections of the undulator. In this paper a preliminary design of this device, performed with RADIA code, is proposed,. The phase shifter consists of two groups of a few permanent magnets, arranged as in the main undulator in a variable gap magnet assembly. Adjusting the gap allows to correct the electron-radiation phase difference. Results from beam dynamics simulation, performed with GENESIS code, show the impact of the phase shifter on the characteristics of the output laser field. |
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| TUPP013 | Spectral Properties of Planar Bi-Harmonic Undulators and Their Use for FEL Operation | |
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We study the spectral details of planar bi-harmonic undulators and show that they have quite interesting properties. They can indeed be exploited to enhance or suppress harmonics and can be exploited in high gain segmented FEL devices to make more efficient the mechanisms of harmonic generation. We also show that the formalism we develop can be extended to the multi-component case and can usefully be exploited to study undulator magnetization errors. |
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| TUPP014 | Coherent Synchrotron Radiation: A Simulation Code Based on the Non-Linear Extension of the Operator Splitting Method | |
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The coherent synchrotron radiation (CSR) is one of the main problems limiting the performance of high intensity electron accelerators. A code devoted to the analysis of this type of problems should be fast and reliable: conditions that are usually hardly achieved at the same time. In the past, codes based on Lie algebraic techniques have been very efficient to treat transport problem in accelerators. The extension of these method to the non-linear case is ideally suited to treat CSR instability problems. We report on the development of a numerical code, based on the solution of the Vlasov equation, with the inclusion of non-linear contribution due to wake field effects. The proposed solution method exploits an algebraic technique, using exponential operators implemented numerically in C++. We show that the integration procedure is capable of reproducing the onset of an instability and effects associated with bunching mechanisms leading to the growth of the instability itself. In addition, parametric studies are presented on the dependence of the effects on the e-beam energy spread and bunch length, considerations on the threshold of the instability are also developed, and future improvements of the work are presented. |
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| TUPP015 | Theory of Cerenkov Free Electron Lasers | |
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In this paper we show that Cerenkov Free Electron Laser oscillators can be studied using a treatment closely similar to that of the magnetic undulator counterpart. We prove that the saturation dynamics can be modeled by strictly similar formulae and that also for Cerenkov Free Electron Laser the saturation intensity is a quantity of paramount importance. We consider hybrid (undulator and cerenkov) FEL devices and show how they can be exploited to assist the non linear higher order harmonic generation. |
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| THOB001 | Review of Existing Soft and Hard X-Ray FEL Projects | 442 |
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The existing soft and hard X-Ray FEL Projects are discussed, along with the underlying design and technological strategies. We consider two main categories: large facilities, which will involve the joint efforts of big laboratories and will take benefit from the heritage of high energy Physics facilities and smaller devices, which are aimed at exploiting high quality accelerators with modest e-beam energy to reach shorter wavelengths with alternative schemes. We will discuss advantages and drawbacks of the different conceptions and make an outlook to the future developments, with particular attention to combinations of different solutions like exotic undulators, seeding and so on, aimed not only at improving X-ray beam qualities but also at reducing device complexity and cost. |
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| THOC005 | High Gain FEL Oscillators: Inclusion of Pulse Propagation Effects | |
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The theory of pulse propagation of low gain Free Electron Laser oscillators is extended to the high gain regime. The physics underlying the relevant phenomenology is discussed and it is shown that the system dynamics, from small signal to saturation, can be reproduced using simple scaling formulae. The inclusion of non linear harmonic generation is considered too, the performances of a source operating in the extreme UV is considered and compared with those operating in the SASE configuration. |
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| THPP019 | Status of the SPARX FEL Project | 491 |
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The first phase of the SPARX project, now funded by MIUR (Research Department of Italian Government), is an R&D activity focused on developing techniques and critical components for future X-ray FEL facilities. This project is the natural extension of the activities under development within the ongoing SPARC collaboration. The aim is the generation of electron beams characterized by an ultra-high peak brightness with a linear accelerator based on the upgrade of the existing Frascati 800 MeV LINAC and to drive a single pass FEL experiment in the range of 3-5 nm, both in SASE and SEEDED FEL configurations, exploiting the use of superconducting and exotic undulator sections. In this paper we discuss the present status of the collaboration. |
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