The overall SPARC (Sorgente Pulsata Auto-amplificata di Radiazione Coerente) project consists of 4 main lines of activity aiming at several goals: their common denominator is to explore the scientific and technological issues that set up the most crucial challenges on the way to the realization of a SASE-FEL based X-ray source, the SPARX proposal. These are:

Up to 200 MeV Advanced Photo-Injector

Since the performances of X-ray SASE-FEL's are critically dependent on the peak brightness of the electron beam delivered at the undulator entrance, we want to investigate two main issues - generation of the electron beam and bunch compression via magnetic and/or RF velocity bunching - by means of an advanced system delivering 150 MeV electrons, the minimum energy to avoid further emittance dilutions due to time-dependent space charge effects.

SASE-FEL Visible-VUV Experiment

In order to investigate the problems related to matching the beam into an undulator and keeping it well aligned to the radiation beam, as well as the generation of non-linear coherent higher harmonics, we want to perform a SASE FEL experiment, using a segmented undulator with additional strong focusing, to observe FEL radiation at 530 nm and below.

X-ray Optics/Monochromators

The X-ray FEL radiation will provide unique radiation beams to users in terms of peak brightness and pulse time duration (100 fs), posing at the same time severe challenges to the optics necessary to guide and handle such radiation. This project will pursue also a vigorous R&D activity on the analysis of radiation-matter interactions in the spectral range typical of SASE X-ray FEL's (from 0.1 to 10 nm), as well as the design of new optics and monochromators compatible with these beams.

Soft X-ray table-top Source

In order to test these optics and to start the R&D on applications, the project will undertake an upgrade of the presently operated table-top source of X-rays at INFM-Politecnico Milano, delivering 107 soft X-ray photons in 10-20 fs pulses by means of high harmonic generation in a gas.

Elisabetta Pace