beam diagnostics – Lightsources.org

FERMI #LightSourceSelfie

Michele Manfredda is an Italian physicist working at FERMI, the Free Electron laser Radiation for Multidisciplinary Investigations, near Trieste in Italy. Michele words in the PADReS group, which stands for photon analysis delivery and reduction system. The group’s role is to make experiments possible for FERMI users and they look after the optics and diagnostics of the light. As Michele explains, the role involves working in different places and with different teams. His #LightSourceSelfie takes viewers on a fantastic tour of FERMI.

Michele explains that he was first attracted to this field of research by the fact that simple things are done in a very complicated way. When it comes to advice that Michele would give those starting out in their careers, he says, “The advice I would give to someone entering the world of large facilities is go for it. They are crazy environments and you will enjoy it, but remember large facilities can be very time-consuming. So always keep in mind what you can give to science and what science can give you back. Also, find the right people. People you can learn from and people you like to work with because remember, science facilities are wonderful creations but the most wonderful creation is your career, your life. So, as an optical physicist, I tell you don’t be focused on your sample only, be focused mostly on you.”

For decades, particle accelerators have been getting bigger and bigger. In the meantime, ring accelerators with circumferences of many kilometres have reached a practical limit. Linear accelerators in the GHz range also require very long construction lengths. For some years now, however, an alternative is explored: “tabletop particle accelerators” based on the laser excitation of charge waves in plasmas (laser wakefield). Such compact particle accelerators would be particularly interesting for future accelerator-driven light sources, but are also being investigated for high-energy physics. A team from Helmholtz-Zentrum Berlin (HZB) and the Physikalisch-Technische Bundesanstalt (PTB) has developed a method to precisely measure the cross-section of electron bunches accelerated in this way. This brings applications of these new accelerator technologies for medicine and research closer.

The principle of laser wakefield accelerators: A high-power laser excites a charge wave in a plasma, which propagates at the speed of the laser pulse and pulls electrons behind it in its “wake”, thus accelerating them. Electron energies in the GeV range have been achievable with this technique for some time. However, the electron bunches produced in this way have so far been too small and too poorly focused to use the synchrotron radiation they emit, an intense, coherent light that is used for research in many different disciplines.

Read more on the HZB website

Image: Information on beam quality can be extracted via the interference patterns at different focal lengths and photon intensities.

Tag: beam diagnostics

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Beam diagnostics for future laser wakefield accelerators