Collimation of Partially Stripped Ion Beams in the LHC

Andrey Abramov, Laurence Nevay, Roderik Bruce, Nuria Fuster-Martinez, Arkadiusz Gorzawski, Mieczyslaw Krasny, James Molson, Stefano Redaelli, M Schaumann

Research output: Chapter in Book/Report/Conference proceedingConference contribution


In the scope of the Physics Beyond Colliders studies, the Gamma Factory initiative proposes the use of partially stripped ions as a driver of a new type, high intensity photon source in CERN’s Large Hadron Collider (LHC). In 2018, the LHC accelerated and stored partially stripped 208Pb81+ ions for the first time. The collimation system efficiency recorded during this test was found to be prohibitively low. The worst losses were localised in the dispersion suppressor (DS) of the betatron cleaning insertion. Analytic arguments and simulations show that the large losses are driven by the stripping of the remaining electron from the Pb nucleus by the primary collimators. The rising dispersion in the DS pushes the resulting off-rigidity, fully-stripped ions into the aperture of the superconducting magnets. In this study the measured loss maps are compared against results from simulations. Different mitigation strategies are outlined, including a dispersion suppressor (DS) collimator, crystal collimation or an orbit bump.
Original languageEnglish
Title of host publication10th International Particle Accelerator Conference
PublisherJACoW Publishing
Number of pages4
ISBN (Electronic)978-3-95450-208-0
Publication statusPublished - 21 Jun 2019
Event10th International Particle Accelerator Conference, IPAC 2019 - Melbourne, Australia
Duration: 19 May 201924 May 2019


Conference10th International Particle Accelerator Conference, IPAC 2019

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