Beam Diagnostics

Since the beginning of SPARC, the diagnostics R&D has been one of the fundamental developments of the entire project. High brightness beams, as well as plasma accelerated beams, demand particular and dedicated diagnostics. At SPARC_LAB we developed in the years several new ideas and equipment, some of them also tested in other labs, to fulfill these requirements.


Trains of ultrashort electron pulses with THz repetition rate, so-called comblike beams, are assuming an ever growing interest in plasma-based acceleration, as well as in other applications like FEL or THz sources. The manipulation of longitudinal phase space to investigate different bunch configurations, in terms of energy and time separation, is founded on the knowledge of the 6D phase space of each single bunch in the train. We developed COMB beam diagnostics tailored to this purpose.


To measure the longitudinal shape of the electron beams in a totally not intercepting way we used EOS (Electro Optical Sampling) with spatial decoding. We implement EOS in very different scenarios for many purposes, detailed on the EOS Diagnostics page.


We designed and built an innovative beam diagnostic device, the emittance meter, consisting of a movable emittance measurement system, to fully characterize the beam dynamic of high brightness beams.


We employed the electromagnetic radiation of the electron beam in different diagnostic schemes.

Optical Transition Radiation (OTR) is emitted when a charged particle crosses the boundary between two media with different index of refraction. Our diagnostics is focused on the incoherent part of the radiation emitted at wavelength shorter than the bunch length, in the visible range.

When a charged particle passes through the aperture on a boundary between two media with different refraction indices, diffraction radiation (DR) is emitted both into the forward and the backward direction. Since the beam passes through a hole, DR provides a nonintercepting diagnostics tool, and is therefore well suited for measuring parameters of high charge density beams in a parasitic way.



Contact person: A. Cianchi, alessandro.cianchi@lnf.infn.it, Tel. (+39) 069403-2465

Last update: 02/2019