LA³NET and oPAC Fellows use Lightsaber to Diagnose Particle Beam

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In time for the global launch of the latest Star Wars movie “The Force Awakens” LA³NET Fellow Thomas Hoffmann (CERN) and oPAC Fellow Konstantin Kruchinin (Royal Holloway University of London) have published their research results on the use of a laserwire scanner for the CERN Linac4 beam in the journal Physical Review Special Topics: Accelerators and Beams.

Similar to a lightsaber in the iconic movie series, their laser wire can simply cut through a beam of negatively charged H- ions and is able to precisely measure the beam’s profile and even emittance – a crucial parameter in any particle beam.


Thomas and Konstantin joined forces with colleagues from CERN and the UK and successfully measured the distribution of photo-neutralized particles.  This allowed them to reconstruct the transverse emittance of the beam. In particular they managed to characterize the vertical phase-space distribution of a 3 MeV beam during the commissioning of the LINAC4 accelerator.

Thomas, who led the study, commented: “We have compared our results to data obtained with a commonly used slit and grid method and found a very good agreement. The beauty of our method is that we hardly disturb the beam. We have developed a truly non-invasive measurement alternative and have shown that it is working extremely well.” The paper has just been accepted and will soon be available via the journal home page.

Prof. Carsten Welsch from the Cockcroft Institute/University of Liverpool who coordinates both the LA3NET and oPAC projects added: “It is a pleasure to see these excellent results as a results from a collaboration between two of Europe’s largest research networks. Using laser beams for beam diagnostic and acceleration purposes has been a focus within these R&D projects. They were also successfully applied for precision velocimetry and to generate strong forces for highest gradient beam acceleration in high power and dielectric laser acceleration.” These promising results will now form the basis for follow-on R&D projects.