Introduction to particle accelerators Walter Scandale CERN AT

Introduction to particle accelerators Walter Scandale CERN - AT department Lecce, 17 June 2006

Introductory remarks Particle accelerators are black boxes producing u either flux of particles impinging on a fixed target u or debris of interactions emerging from colliding particles In trying to clarify what the black boxes are one can u list the technological problems u describe the basic physics and mathematics involved Most of the phenomena in a particle accelerator can be described in terms of classical mechanics and electro-dynamics, using a little bit of restricted relativity However there will be complications: u in an accelerator there are many non-linear phenomena (stability of motion, chaotic single-particle trajectories) u there are many particles interacting to each other and with a complex surroundings u the available instrumentation will only provide observables averaged over large ensembles of particles In two hours we can only fly over the problems just to have an overview of them W. Scandale, Introduction to Particle Accelerators 12 June 2005 2

Inventory of synchrotron components W. Scandale, Introduction to Particle Accelerators 12 June 2005

Bending magnet Efficient use of the current -> small gap height Field quality -> determined by the pole shape Field saturation -> 2 Tesla BEarth = 3 10 -5 Tesla B > 2 Tesla -> use superconducting magnets W. Scandale, Introduction to Particle Accelerators 12 June 2005 BLHC = 8. 4 Tesla

Quadrupole magnet Vertical focusing Horizontal defocusing g=gradient [T/m] W. Scandale, Introduction to Particle Accelerators 12 June 2005

Alternate gradient focusing QF QD QF W. Scandale, Introduction to Particle Accelerators 12 June 2005

Mechanical analogy for alternate gradient W. Scandale, Introduction to Particle Accelerators 12 June 2005

Basic 2 -D equation of motion in a dipolar field W. Scandale, Introduction to Particle Accelerators 12 June 2005

Basic 2 D equation of motion W. Scandale, Introduction to Particle Accelerators 12 June 2005

Basic 2 D equation of motion FODO structure Periodic envelop Cos-like trajectory Sin-like trajectory Multi-turn trajectory W. Scandale, Introduction to Particle Accelerators 12 June 2005

Longitudinal stability Momentum compaction W. Scandale, Introduction to Particle Accelerators 12 June 2005

Chromaticity and sextupole magnet Dispersion orbit W. Scandale, Introduction to Particle Accelerators 12 June 2005

Chromaticity correction and non-linear resonance W. Scandale, Introduction to Particle Accelerators 12 June 2005

Emittance W. Scandale, Introduction to Particle Accelerators 12 June 2005

Synchrotron radiation W. Scandale, Introduction to Particle Accelerators 12 June 2005

Synchrotron radiation and beam size Adiabatic damping Synchrotron light emission W. Scandale, Introduction to Particle Accelerators 12 June 2005

Effect of synchrotron light W. Scandale, Introduction to Particle Accelerators 12 June 2005

Collective effects W. Scandale, Introduction to Particle Accelerators 12 June 2005

Instabilities and feedback W. Scandale, Introduction to Particle Accelerators 12 June 2005

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Space charge W. Scandale, Introduction to Particle Accelerators 12 June 2005 21

Beam size W. Scandale, Introduction to Particle Accelerators 12 June 2005 22

Fixed target versus collider rings Fixed target Collider Advantage Bruno Touschek W. Scandale, Introduction to Particle Accelerators 12 June 2005

Lepton versus hadron colliders -> (At the parton level ) -> W. Scandale, Introduction to Particle Accelerators 12 June 2005