63 research outputs found
The PROMETEO Code: A flexible tool for Free Electron Laser study
Prometeo is a multi-particle code developed at ENEA within the framework of scientific programs aimed at studying and developing Free Electron Laser (FEL) sources. The code has been used either as a research tool to understand the dynamics of FELs operating in different configurations and as a practical tool to design FEL devices. In this paper we describe the structure of the code and its capability in describing either Oscillator and Single pass configuration. We compare Prometeo performances with those of other existing codes and finally comment on its role in designing high-gain devices as the SPARC source
Fractional derivatives, memory kernels and solution of a free electron laser volterra type equation
The high gain free electron laser (FEL) equation is a Volterra type integro-differential equation amenable for analytical solutions in a limited number of cases. In this note, a novel technique, based on an expansion employing a family of two variable Hermite polynomials, is shown to provide straightforward analytical solutions for cases hardly solvable with conventional means. The possibility of extending the method by the use of expansion using different polynomials (two variable Legendre like) expansion is also discussed
Deep Saturated Free Electron Laser Oscillators and Frozen Spikes
We analyze the behavior of Free Electron Laser (FEL) oscillators operating in
the deep saturated regime and point out the formation of sub-peaks of the
optical pulse. They are very stable configurations, having a width
corresponding to a coherence length. We speculate on the physical mechanisms
underlying their growth and attempt an identification with FEL mode locked
structures associated with Super Modes. Their impact on the intra-cavity
nonlinear harmonic generation is also discussed along with the possibility of
exploiting them as cavity out-coupler.Comment: 28 page
Fel Oscillators with Tapered Undulators: Inclusion of Harmonic Generation and Pulse Propagation
We review the theory of FEL oscillators operating with tapered undulators. We
consider the case of a uniform tapering and introduce a parameter which
characterizes the effect of the tapering on the gain and on the saturation
intensity. We analyze the effect of the tapering on the FEL dynamics by
including the pulse propagation effects too. We analyze the importance of
tapering as a tool to model the optical pulse shapes and to control the higher
harmonic intensities
Perspectives of 2D and 3D mapping of atmospheric pollutants over urban areas by means of airborne DOAS spectrometers
tants,
offering numerous advantages over conventional networks of in situ analysers. We propose some innovative
solutions in the field of DOAS (Differential Optical Absorption Spectroscopy) remote systems, utilizing diffuse solar
light as the radiation source. We examine the numerous potentialities of minor gas slant column calculations,
applying the «off-axis» methodology for collecting the diffuse solar radiation. One of these particular approaches,
using measurements along horizontal paths, has already been tested with the spectrometer installed on board the
Geophysica aircraft during stratospheric flights up to altitudes of 20 km. The theoretical basis of these new measurement
techniques using DOAS remote sensing systems are delineated to assess whether low altitude flights can
provide 2D and 3D pollution tomography over metropolitan areas. The 2D or 3D trace gas total column mapping
could be used to investigate: i) transport and dispersion phenomena of air pollution, ii) photochemical process rates,
iii) gas plume tomography, iv) minor gas vertical profiles into the Planetary Boundary Layer and v) minor gas flux
divergence over a large area
The FEL SASE operation, bunch compression and the beam heater
We discuss the conditions required for an optimal SASE FEL operation when
bunch compression techniques are exploited to enhance the bunch peak current.
We discuss the case of velocity bunching and magnetic bunch compression. With
the reference to the latter technique we provide a quantitative estimate of the
amount of laser heater power necessary to suppress the micro-bunching
instability without creating any problem to the SASE dynamic
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Status of the SPARC-X Project
SPARC-X is a two branch project consisting in the SPARC test facility dedicated to the development and test of critical subsystems such as high brightness photoinjector and a modular expandable undulator for SASE-FEL experiments at 500 nm with seeding, and the SPARX facility aiming at generation of high brilliance coherent radiation in the 1.5-13 nm range, based on the achieved expertise. The projects are supported by MIUR (Research Department of Italian Government) and Regione Lazio. SPARC has completed the commissioning phase of the photoinjector in November 2006. The achieved experimental results are here summarized together with the status of the second phase commissioning plans. The SPARX project is based on the generation of ultra high peak brightness electron beams at the energy of 1 and 2 GeV generating radiation in the 1.5-13 nm range. The construction is at the moment planned in two steps starting with a 1 GeV Linac. The project layout including both RF-compression and magnetic chicane techniques has been studied
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