Beam loss mechanisms in Beam loss mechanisms in relativistic heavy-ion relativistic heavy-ion colliders colliders Roderik Bruce CERN - BE/ABP, Geneva, Switzerland MAX-lab, Lund University, Sweden Supervisors: John M. Jowett, CERN Simone Gilardoni, CERN Erik Wallén, MAX-lab PhD thesis, Lund University 2009
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Beam loss mechanisms in relativistic heavy-ion colliders
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Beam loss mechanisms inBeam loss mechanisms inrelativistic heavy-ion relativistic heavy-ion
colliderscolliders
Roderik Bruce
CERN - BE/ABP, Geneva, SwitzerlandMAX-lab, Lund University, Sweden
Supervisors:John M. Jowett, CERN
Simone Gilardoni, CERNErik Wallén, MAX-lab
PhD thesis, Lund University 2009
2011.03.31 R. Bruce - PAC11 Awards Session 2
Large Hadron Collider
• Designed to collide 7 TeV protons and 7 Z TeV Pb82+ ions (now 3.5 Z TeV = 1.38 A TeV)
• Will operate about 1 month per year with ions
• Superconducting magnets: most operating at 1.9K
• Nominal stored beam energy: 362 MJ for protons, 3.81 MJ for ions
transfer line
Injectionbeam 1
transfer line
Injection beam 2
collimators
accelerating RF system
Beam extraction
collimators
=> Machine protection crucial design parameter!
Losses must be controlled!
2011.03.31 R. Bruce - PAC11 Awards Session 3
• During operation with ions, loss mechanisms not present with protons exist
• Creation of ions with charge-to-mass ratio different from the main beam:– Interactions at IP
(fragmentation, electron capture, electromagnetic dissociation)
– Interactions in collimator (fragmentation, electromagnetic dissociation)
• Follow dispersion, lost in localized spot
• Example: Bound-Free pair production between colliding beams
Ion beam losses
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Example: BFPP at IP2Example: BFPP at IP2
Secondary Pb81+ beam emerging from IP and impinging on beam
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Secondary Pb81+ beam emerging from IP and impinging on beam
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Main Pb82+ beamMain Pb82+ beam
Interaction point
Interaction point
Beam
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Beam
screen
2011.03.31 R. Bruce - PAC11 Awards Session 4
Dispersive orbits from ALICEDispersive orbits from ALICE
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Nom.BFPPEMD1EMD2
Beam direction
• Acceptance: ||<0.006 (=fractional deviation in magnetic rigidity)
• thanks to the following people for valuable help and advise:– Supervision: J.M. Jowett, S. Gilardoni and E. Wallén– Other collaborators and people I want to thank:
G. Arduini, R. Assmann, S. Aumon, M. Blaskiewicz, G. Bellodi, C. Bracco, H.H. Braun, D. Bocian, B. Dehning, R. DeMaria, A. Drees, M. Eriksson, A. Ferrari, W. Fischer, M. Giovannozzi, B. Goddard, M. Gresham, B. Holzer, J-B. Jeanneret, S.R. Klein, M. Magistris, L. Ponce, S. Redaelli, G. Robert-Demolaize, T. Roser, B. Schröder, G.I. Smirnov, M. Stockner, S. Tepikian, V. Vlachoudis, T. Weiler, S. White, C. Zamanzas, F. Zimmermann