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Overview of the Proposed Antiproton Facility

Overview of the Proposed Antiproton Facility. Antiproton production facility High Energy Storage Ring (HESR) Electron cooling Detector concept Simulations of the detector properties Conclusions. Antiproton Production. 50 MeV Proton Linac 5 Hz, T=0.1 ms, 50 mA

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Overview of the Proposed Antiproton Facility

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  1. Overview of the Proposed Antiproton Facility • Antiproton production facility • High Energy Storage Ring (HESR) • Electron cooling • Detector concept • Simulations of the detector properties • Conclusions

  2. Antiproton Production • 50 MeV Proton Linac 5 Hz, T=0.1 ms, 50 mA • SIS 18, 51012 protons up to 2 GeV • SIS 100, 4-5 bunches • up to 29 GeV • Pbar production: • 108 pbar / bunch • Collector Ring • 5 s cooling • Storage in the NESR • at 3 GeV for ~ 20 min. • Reinject into SIS100 • Experiments at HESR

  3. Antiproton Storage Ring Number of p in HESR 5x1010 p production rate 2x107/sec High luminosity mode: (stochastic cooling) Beam momentum 1.5 - 15 GeV/c Luminosity < 2x1032 cm-2s-1 dp/p ~10-4 High resolution mode: (electron cooling) Beam momentum 1.5 - 8 GeV/c Luminosity ~ 1031 cm-2s-1 dp/p ~ 10-5

  4. Momentum spread of beam can be reduced by superimposing the p beam with an electron beam of the same average velocity. Electron Cooling

  5. Y(v) F(v) v Fokker-Plank Equation Electron cooling is described by theFokker-Plank equation. where Y(v) is the p velocity distribution, F is the cooling force, m the ion mass and D the diffusion constant.

  6. General Purpose Detector • Detector requests: • nearly 4p solid angle (partial wave analysis) • high rate capability (2107 annihilations/s) • good PID (g, e, m, p, K, p) • momentum resolution (~1%) • vertex reconstruction for D, K0S, L (for Dct = 317mm) • efficient trigger (e, m, K, D, L) • modular design (Hypernuclei experiments)

  7. Micro Vertex Detector (MVD) 7.2 mio. barrel pixels 50 x 300 μm 2 mio. forward pixels 100 x 150 μm 200 mm

  8. s(DD0) = 51 mm s(DZ0) = 82 mm MVD Performance Requirement: significantly better than 100mm (Dct = 317mm, D0ct = 124 mm)

  9. example event: pp f f  4K Straw Tube Tracker STT

  10. Mini Drift Chambers MDC Resolution: 150 mm

  11. Momentum Resolution Polar angle resolution sQ 1 mrad Pt resolution sP/P  1-2 % N.B. 2 T solenoid field in z-direction, i.e. no fringe field!

  12. Invariant Mass Resolution Example reaction: pp  J/y+F(s = 4.4 GeV/c2) s(J/y) = 35 MeV/c2 s(F) = 3.8 MeV/c2 F K+K- J/y m+m-

  13. PID with DIRC Concept similar to the existing DIRC at BaBar

  14. DIRC Parameters

  15. Pion/Kaon Separation High kaon efficiency with about 1-2% pion misidentification probability.

  16. Pion/Kaon Acceptance The simulated data distributions below are for pions and kaons from the reaction p p  D+ D- with Tbeam = 6.7 GeV/c s = 4 GeV

  17. Electromagnetic Calorimeter

  18. Invariant Mass Resolution Example reaction: pp  J/yh  mmgg (s = 4.4 GeV/c2) m(h) = 0.501 GeV/c2s(h) = 0.020 GeV/c2

  19. Electron Pion Separation e Deposited energy = p*c p MIP, thus DE < p*c Above 0.4 GeV/c about 0.001 of pions misidentified p-Suppression

  20. Muon Detector MUD Flux return as hadron absorber is 50 cm thick in the transverse direction. Threshold is 1.3 GeV/c

  21. Muon Performance High muon efficiency above 1.3 GeV/c About 1% probability for p misidentification pmisidentification midentification

  22. Summary & Outlook • Antiproton facility • HESR: high luminosity, electron cooled beam • Detector concept • Performance of detector components studied • OPEN POINTS • Background generator (Dubna) • Forward spectrometer • Target • …

  23. Antiproton Physics Study Group T. Barnes8, D. Bettoni6, R. Calabrese6, W. Cassing5, M. Düren5, S. Ganzuhr1, A. Gillitzer7, O. Hartmann2, V. Hejny7, P. Kienle9, H. Koch1, W. Kühn5, U. Lynen2, R. Meier11, V. Metag5, P. Moskal7, H. Orth2, S. Paul9, K. Peters1, J. Pochodzalla10, J. R.5, M. Sapozhnikov3, L. Schmitt9, C. Schwarz2, K. Seth4, N. Vlassov3, W. Weise9, U. Wiedner12

  24. General Purpose Detector • Detector requests: • nearly 4p solid angle • high rate capability (2107 annihilations/s) • good PID (g,e,m,p,K,p) • efficient trigger (e,m,K,D,L) pp  Y‘ pp (s=3.6 GeV)ff4K Y‘m+m- J/Ym+m-

  25. HESR Detector • Pellet-Target: 1016 Atoms/cm2 20-40 mm • MicroVertexDetektor: (Si) 5 layers • Straw-Tubes: 15 skewed double layers • RICH: DIRC and Aerogel (Proximityfocussing) • Straw-Tubes + Mini-Drift-Chambers • PbWO4-calorimeter 17X0 • 2T-Solenoid & 2Tm-Dipole • Muon filter • EM- & H-cal. near 0°

  26. Target • A fiber/wire target will be needed for D physics, • A pellet target is conceived: • 1016 atoms/cm2 20-40 mm • Open point: heating of the beam 1 mm

  27. Simulation Scheme Tools: ROOT for data handling and analysis PLUTO++ for event generation (ROOT library) phase space / exp. distributions for certain reactions read in by Geant4 or processed directly in ROOT Geant4 for detailed detector simulations currently used version: 4.4.0 linked with ROOT to use ROOT file I/O Simulation in GEANT4 Analysis with HAF PLUTO in ROOT Fast Simu In ROOT

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