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Basic principles of accelerators

Basic principles of accelerators. Cyclic accelerators : History & chronology, Basic principles. Classification. Frontier projects. Linear accelerators : Basic principles. Classification Future projects. Part I. Part II. G.Trubnikov (JINR) Dubna 2011. Accelerator – instrument ?.

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Basic principles of accelerators

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  1. Basic principles of accelerators Cyclic accelerators: History & chronology, Basic principles. Classification. Frontier projects. Linear accelerators: Basic principles. Classification Future projects Part I Part II G.Trubnikov (JINR) Dubna 2011

  2. Accelerator – instrument ? The appearance and development of the accelerators, is mainly connected with needs of nuclear physicists and physicists of high energy. The knowledge about fundamental characteristic of the matters is connected with explanation and understanding of the phenomenas, occurring on small distanses. The scale of the distances for molecular and atomic physics refers to 10-8 cm, physics of the elementary particles requires less lengths. Today most small particle, measured in experiment is electron (< 10-16cm), but by theoretical assumptions this must be point-like particle. Nucleui forces comparable to the radius of protron (~ 10-13cm) refers to the energy of colliding particles of the order of several MeV. Corresponding estimations can be done if to use principe of the uncertainties Then for x=10-13 cm we immediately get p ~ 200 MeV/c.Distance of the order 10-16 cm requires energy 1-10 GeV. The discoveries had been made on accelerators in this energy field are: family of φ - particles, particles with new quantum number. The further development of the theoretical presentations supported by possibility of new accelerators had brought to discovery of parton structure of hadrons, neutral and charged vector bosons. The next expectation is probably connected with finding of Higgs particles (1 TeV for pp ???). Further development of intensive accelerators is a possibility of their usage as generators of the secondary particles: neutrons, mesons, neutrionos.

  3. … portion of theory…

  4. In Accelerator physics all forces acting on the particle are of electromagnetic nature. We can take for rough estimations only Lorentz force (electromagnetic field): Total particle energy: As soon as V  B - energy and particle mass are not changed by magnetic field. Only electric field does accelerate: Electric and magnetic field are connected with Maxwell equation: 1eV = 10-3 keV = 10-6 MeV = 10-9GeV = 10-12 TeV 1[eV] 1.60218  10-19 [Coulomb]  1[V] = 1.60218  10-19 [J]

  5. accelerator injector Cathode Anode Electron beam Particle detectors particle orbit target ~ U Beam extraction system Trajectory form Linear Cyclic

  6. Fixed target Colliding particles

  7. Storage ring Intersections of the rings Colliding beams Injector accelerator Injector accelerator

  8. Particle motion Transverse plane: Horizontal + vertical Longitudinal plane: Longitudinal (Synchrotron) Oscillations Transverse (Betatron) Oscillations Mathematical pendulum with external force (acc.gap)‏ Academician V.I.Veksler, 1944

  9. Soft focusing magnet R ! Magnetic field gradient ( field index)

  10. Strong focusing: N.Christofilos; E.Curant, M.Livingston, H.Snyder (Brookhaven, USA, 1952)‏ Alternate focusing Transformation matrix

  11. Dipole magnet Quadrupole magnet Sextupole magnet Stability diagram

  12. Phase space Particle coordinate vector Planes: (x,x’), (z,z’), (s,p/p), (x,s), ….. )‏ x` x Beam envelope :

  13. Liuville Theoreme Isolated systems !!!

  14. Radiation cooling Electron cooling Stochastic cooling Laser cooling  Pick-up V kicker Beam cooling and damping: Emittance and momentum spread decreasing !!!

  15. Beam instabilities - Due to space charge: Incoherent tune shift, Landau damping, … - Transverse and longitudinal instabilities due to chamber characteristics - Instabilities due to beam-chamber interactions - due to synchrotron radiation - ….. Incoherent oscillations Coherent oscillations

  16. Main beam parameters: Sort of particles Beam current (intensity)‏ Bunched / coasting Transverse size – emittance  Momentum (energy) spread ….. Luminosity

  17. 5 300000 500 Main “accelerator” parameter of the experiment Luminosity 1 barn = 10-24cm2

  18. Cyclic accelerators

  19. Classical cyclotron In 1930 E.Lawrence (USA) had created first cyclic accelerator – cyclotron with energy 1 MeV (diameter 25 cm). S.Livingstone and E.Lawrence near by cyclotron of the next generation. It let accelerate protons and deutrons up to energies of several MeV

  20. At a constant magnetic field it is possible to provide such a gain of energy in the gap that the increase of the particle revolution period will be equal to the period of radio-frequency oscillations and on the next turn the particle will be in the desired phase again. Such way of acceleration - a classical cyclotron, an orbit of a particle is untwisted spiral in it. To keep the synchronism frequency of the acceleration field should satisfy to a condition: 0==eB/m. Thus kinetic energy grows linearly with number of turns: Ekin  2eU. After reaching the maximal energy and accordingly the maximal radius of the orbit, the accelerated particles are extracted to a target for experiments Dees - two high-voltage hollow D-shaped electrodes

  21. Isochronous cyclotron Let’s start to vary parameters (in here - B) to achieve higher energy… Alternate sector structure R B  Magnet poles

  22. Synchrocyclotron (phazotron) We continue to vary with parameters (in here - RF ) to achieve higher energy… Mechanical variators

  23. Bending magnet Particle orbit Focus magnet RF resonator with acc.field Synchrotron

  24. Linear induction accelerator Betatron First “circular electron accelerator”. Electrons are in the wire of a secondary coil accelerated by an electro motive force generated by a time varying magnetic flux penetrating the area enclosed by the secondary coil. Electron beam is circulating in a closed doughnut shaped vacuum chamber. D.Kerst with betatrons. Small – 2,3 MeV Big – 25 MeV Wideroe ½ condition

  25. Microtron Particle emerging from a source pass through the accelerating cavity and follow then a circular orbit in a uniform magnetic field leading back to the accelerating cavity. After each acceleration the particles follow a circle with a bigger radius till they reach the boundary of the magnet. Electron orbit resonator vacuum chamber Race track microtron Bending magnets Accelerating structure

  26. Accelerators in particle physics today. Projects of the nearest future. Particle Physics - colliders Hadron colliders Tevatron (Fermilab) pp-bar top-quark physics, higgs (?)‏ RHIC (BNL) pp, ii “nuclear matter at extreme state” LHC (CERN) pp, ii higgs, SuSy, “further everywhere…” Lepton (e+e-) colliders VEPP-4M (Budker INP, Novosibirsk) CESR (Cornell) BEPC (IHEP, Beijing) J/ and ’ mesons KEKB (KEK), PEP-II (SLAC): B-quark DAFNE (Frascatti): -mezon VEPP-2000 (Budker INP, Novosibirsk)“around -mezon”  and J/ mesons, -lepton Hadron-lepton (pe+ore-) collider HERAgluon and spin physics

  27. Run IIA pp 2x900 GeV 1.41032 cm-2s-1 - C = 6.28 km Tevatron (Fermilab)

  28. Relativistic Heavy Ion Collider(BNL) pp 2x250 GeV, 11031 cm-2s-1 pp 2x250 GeV, 11031 cm-2s-1 ? ii 2x100 GeV, 21026 cm-2s-1

  29. Hadron-Electron Ring Accumulator Parameters: Circumference 6336 m Energy 30(e+or e-) x 820(p) GeV Luminosity 3.81031 cm-2s-1

  30. Hadron colllider LHC Large Hadron Collider Machine Circumference 26658.883 m Revolution frequency 11.2455 kHz pp-collisions Collision energy 7 TeV Injection energy 450 GeV Number of particles 3.231014 DC beam current 0.582 A Luminosity 1.01034 cm-2s-1 Pb82+ x Pb82+ Collision energy 2.76 TeV/u Number of ions 41010 DC beam current 6.1 mA Luminosity (collision = 0.5 m) 1.01027 cm­²s­¹

  31. . ROKK-1M Detector KEDR Colliding Electron-Positron Beams VEPP-4М e+e- collider 2x6 GeV, Circumference 366 m Luminosity 31031 cm-2s-1 at 5 GeV and 1X1 bunches 21030 cm-2s-1at 2 GeV and 2x2 bunches

  32. Beijing Electron Positron Collider Energy 2 x (1.55 - 2.8 GeV)‏ Circumference 240.4 m, Peak luminosity (after upgrade) 11033 cm-2s-1

  33. KEKB - An Asymmetric Electron-Positron Collider for B Physics (KEK – High Energy Accelerator Research Organization)‏ LER HER Particles e+ e- Energy, GeV 3.5 8 Circumference, m 3016.26 H , nm 18 24 I, A 1.73 1.26 Nbunches 1388 x /y 0.11/0.09 0.07/0.05 life , min 140 170 L(t)dt 1 fb-1 per day Peak luminosity 1.561034 cm-2s-1

  34. Accelerators with «fixed target» 1. SPS (CERN)‏ 2. MAIN Injector (Fermilab)‏ 3. U-70 (IHEP)‏ 4. TWAC (ITEP, Moscow)‏ 5. Nuclotron JINR 6. CEBAF(JLab)‏ ( Linac – LANL)‏ 7. KEK-PS 8. J-PARC

  35. CEBAF set to double energy upgrading the Continuous Electron Beam Accelerator Facility to 12 GeV ContinuousElectron BeamAcceleratorFacility (Jefferson National Laboratory)‏

  36. Proton Synchrotron KEK-PS 12 Gev, 5.71012 p/pulse, repetition rate 0.5 Hz, 1.81012 p/s J-PARC Tokyo K2K and J-PARC K-to-K: KEK to Kamiokande K2K - Long-baseline Neutrino Oscillation Experiment J-PARC: Japaneze Proton Accelerator Complex Linac: H- , 600 (400) MeV RCS 3 GeV proton synchrotron, 25 Hz repetition rate MR (Main Ring) 50 Gev, <Ip> = 15 A  0.931013 p/s, <Pbeam> = 750 kW, repetition rate 0.3 Hz

  37. Synchrocyclotrons: JINR Phasotron (560 MeV)‏ Synchrocyclotron PINP (1 GeV)‏ Ring Cyclotron of PSI (590 MeV)‏ TRIUMF (500 MeV)‏

  38. The 590 MeV Ring Cyclotron of PaulScherer Institute Injection Energy 72 MeV Extraction Energy 590 MeV Beam Current 1.6 mA

  39. Projects of the future JINR IMP Lanzhou ORNL RIKEN GSI  FAIR

  40. Facility for Antiproton and Ion Research GSI (Darmstadt, Germany)‏ SIS100, SIS300 – superconducting proton (ion) synchrotrons CR – Cooler storage Ring NESR – “New ESR” RESR – cooler storage ring HESR – High Energy Storage Ring FLAIR - Facility for Low-energy Antiproton and Ion Research FAIR start of construction 2011 commissioning – 2018…

  41. The first and unique superconductive accelerator (synchrotron) of heavy ions in the Russian Federation - Nuclotron at JINR - commissioned in 1993. The field of research - relativistic heavy ion physics. Stable operation ~1500-2000 hours/year (from 2011 it is planned to increase up to 3000-4000 hours/year). Successfully operated experimental set-ups on the internal beam (2 collaborations) and on the slow extracted beam (12 collaborations) Accelerated particles: p, d, He, Li, B, C, N6+, N7+, Mg, Ar16+, Fe24+; beam intensity – up to 5×1010, polarized beams d,Energy range: 0.35-2.5 GeV/n. Starting from 2012: 0.35-5 GeV/n, heavy ions with А>100, intensity about 1011 particles (d) project NICA/MPD Nuclotron-based Ion Collider fAcility Study of the nuclear matter at extremal states (search for the mixed phase and critical points): Elab~ 64 AGeV, √sNN = 4-11 GeV/u, L= 1027sm2s-1 2

  42. Nuclear matter physics at FAIR/NICA energies s s u d s u Λ ? Λ • Nuclear equation-of-state, quarkyonic matter at high densities?: What are the properties and the degrees-of-freedom of nuclear matter at neutron star core densities? • Hadrons in dense matter: What are the in-medium properties of hadrons? Is chiral symmetry restored at very high baryon densities? • Strange matter: Does strange matter exist in the form of heavy multi-strange objects? • Heavy flavor physics: How ist charm produced at low beam energies, and how does it propagate in cold nuclear matter?

  43. We classified it ! But some conclusion is necessary

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