Storage Rings for Charged Particles Kai Hock Cockcroft Institute and University of Liverpool Birmingham University, 24 February 2009

Birmingham, 24 Feb 09: Storage Rings2 Outline Major uses of the charged particle storage rings Basic principles and designs Beam dynamics and stability Relevance to the atom storage ring Ideas for research and development

Birmingham, 24 Feb 09: Storage Rings3 Major uses of the charged particle storage rings Synchrotron light source – Stores electrons – Produces high quality radiation for scientific experiments Damping rings – Stores electrons or positrons – Produces very narrow beams for particle physics experiments Others – Storing muons to produce neutrinos – Cooling protons for particle physics experiments – Cooling ions for nuclear physics experiments, etc.

Birmingham, 24 Feb 09: Storage Rings4 The Diamond Synchrotron, Oxfordshire

Birmingham, 24 Feb 09: Storage Rings5 The ATF Damping Ring, Japan

Birmingham, 24 Feb 09: Storage Rings6 Basic Principles and Design Charged particles are guided in a vacuum pipe around a ring using dipole magnetic fields. They are strongly focused into bunches using quadrupole magnetic fields and rf cavity electric field – the key to stable circulation. Fine tuning to the focusing is made using sextupole magnets. Energy is lost by radiation when particles are bent by magnetic fields, or by collision with residual gas. Energy is replenished in the rf cavity by electric fields in the same direction as the particle orbit. Diagnostic instruments are available to measure beam position, beam profile and radiation profile.

Birmingham, 24 Feb 09: Storage Rings7 Damping Ring for the Linear Collider injection extraction e+e+ 8 RF cavities 10 RF cavities wiggler IP wiggler accelerate particles alternating magnetic fields to cool electrons

Birmingham, 24 Feb 09: Storage Rings8 Enabling Technologies Beam position monitor Quadrupole magnet Wiggler Dipole magnetSuperconducting rf cavity Sextupole magnet

Birmingham, 24 Feb 09: Storage Rings9 Basic Principles of Operation

Birmingham, 24 Feb 09: Storage Rings10 Injection/Extraction trajectory of stored beam trajectory of incoming beam preceding bunch following bunch empty RF bucket injection kicker

Birmingham, 24 Feb 09: Storage Rings11 Injection and extraction kickers Technical subsystems

Birmingham, 24 Feb 09: Storage Rings12 Bending and focusing magnets Dipole field for bending Quadrupole field for focusing

Birmingham, 24 Feb 09: Storage Rings13 Radiation damping stabilises the particle particle trajectory closed orbit emitted photon bending magnet

Birmingham, 24 Feb 09: Storage Rings14 Wiggler increases the radiation rate

Birmingham, 24 Feb 09: Storage Rings15 rf cavity replenishes the lost energy

Birmingham, 24 Feb 09: Storage Rings16 Interaction with beam pipe produces wake fields

Birmingham, 24 Feb 09: Storage Rings17 Scattering from residual gases cause instability

Birmingham, 24 Feb 09: Storage Rings18 Feedback systems stabilises the particles single bunch shown at different times pick-up amplifier kicker y p y

Birmingham, 24 Feb 09: Storage Rings19 Atom Ring by Georgia Tech Electron ring in Oxfordshire Relevance to Atom Ring

Birmingham, 24 Feb 09: Storage Rings20 Comparison of main features Similarities with the charged particle ring – Magnetic field can be used to guide the particles – Scattering from gas molecules shortens lifetime of particles – Same beam dynamics theory can be applied – Particles can be organised into bunches Differences in the atom ring – Energy is orders of magnitude smaller – No synchrotron radiation – Gravity effect is significant

Birmingham, 24 Feb 09: Storage Rings21 Atom Interferometry for Inertial Guidance The ICE Cube, Institut dOptique, France

Birmingham, 24 Feb 09: Storage Rings22 Some ideas for research and development Related activities around the world – Molecule storage rings, Netherlands: molecular experiments – ICE cube, France: inertial sensing project for space underway – Sagnac interferometer, Strathclyde: inertial sensing with atom ring – Atom chip interferometry, Imperial: precise control developed Ideas from accelerator physics – Strong focusing in all three dimensions for long term stability – Beam stability studies and feedback control systems – Energy source: The equivalence of an rf cavity? – Component ideas? Injectors, extractors, kickers, rings, focusing magnets – Presence of Intrabeam scattering, beam beam interactions? – Designing lines and lattices for atom transport and manipulation

Birmingham, 24 Feb 09: Storage Rings23 Linear Collider and the Atom Chip The International Linear Collider Atom Chip Interferometry at Imperial College

Birmingham, 24 Feb 09: Storage Rings24