GSI Helmholtzzentrum für Schwerionenforschung GmbH Status of the FAIR Antiproton Target K. Knie

GSI Helmholtzzentrum für Schwerionenforschung GmbH FAIR / CERN / FNAL pbar Sources FAIRCERN (AC+AA)FNAL E(p), E(pbar)29 GeV, 3 GeV25 GeV, 2.7 GeV120 GeV, 8 GeV acceptance 240  mm mrad200  mm mrad  30  mm mrad protons / pulse2 × × ≥ 5 × pulse lengthsingle bunch (50 ns)5 bunches in 400 nssingle bunch 1.6 µs cycle time10 s4.8 s1.5 s

GSI Helmholtzzentrum für Schwerionenforschung GmbH pbar target / separator 29 GeV p target & collector pbar separator 240  mm mrad p = 3.82 GeV/c  p/p = ±3%

GSI Helmholtzzentrum für Schwerionenforschung GmbH Main Components

GSI Helmholtzzentrum für Schwerionenforschung GmbH Target R.P. Duperray et al., Phys. Rev. D 68, (2003) seprator acceptance: p pbar = 3.82 GeV/c ± 3% From ~ 2.5 × pbar / (p cm target) ~ 5 × (or 2 %) are "collectable" z / cm y / cm E p = 29 GeV magnetic horn with 400 kA: θ ≤ 80 mrad Ni rod, 110 mm, d = 3 mm graphite air-cooled AL block

GSI Helmholtzzentrum für Schwerionenforschung GmbH Magnetic horn LTspice Simulation: Pulsed Horn Current power pulser room soil shielding duct with 60 cables stripline

GSI Helmholtzzentrum für Schwerionenforschung GmbH pbar target station

GSI Helmholtzzentrum für Schwerionenforschung GmbH Magnets in pbar separator CR type magnets (simplified chambers possible) CR-type yokes, rad. hard coils with polyimide insulation Q1-Q2 and Q3-Q4 will be combined to one longer magnet, respectively Special dipole radiation hard coil (100 MGy) upper part of yoke divided in pieces < 10 t (needed for exchange of the coil) high radiation, no vacuum

GSI Helmholtzzentrum für Schwerionenforschung GmbH horizontal cut vertical cut Dose rates during operation (FLUKA): Construction permit 

GSI Helmholtzzentrum für Schwerionenforschung GmbH pbar building target dump

GSI Helmholtzzentrum für Schwerionenforschung GmbH Residual dose rates / handling: Operation permit: (in work, positive responses from authorities for target exchange/disposal concept obtained)

GSI Helmholtzzentrum für Schwerionenforschung GmbH Residual dose rate around target station air BEAM concrete Handling Area iron

GSI Helmholtzzentrum für Schwerionenforschung GmbH Top view, beam from left to right. Inner part of target station is always shielded Transport concept in building 6c

GSI Helmholtzzentrum für Schwerionenforschung GmbH Transport concept in building 6c Transport container moves to the shaft (1-2). Crane of carrying frame of the shielding flask lifts up the component (3). Concept accepted in construction permit

GSI Helmholtzzentrum für Schwerionenforschung GmbH Detailed study from Kraftanlagen Heidelberg Presented already to authorities: Very positive response obtained Trolley Coupling system Rail system Front door (for intervention only) Inner door Transport concept in building 6c

GSI Helmholtzzentrum für Schwerionenforschung GmbH Transport concept in building 6c

GSI Helmholtzzentrum für Schwerionenforschung GmbH pbar shielding flask: technical design weight: 25 tons

GSI Helmholtzzentrum für Schwerionenforschung GmbH Conversion rates

GSI Helmholtzzentrum für Schwerionenforschung GmbH Production Cross Section Semiempirical formula: R.P. Duperray et al., Phys. Rev. D 68, (2003) Fit of experimental data available in Monte Carlo Codes used in addition: FLUKA, MARS

GSI Helmholtzzentrum für Schwerionenforschung GmbH Production Cross Section p = 3.82 GeV / c, E = 3 GeV, Bρ = 13 Tm

GSI Helmholtzzentrum für Schwerionenforschung GmbH Collectible pbars p pbar = 3.82 GeV/c ± 3% From ~ 2.5 × pbar / (p cm target) ~ 5 × (or 2 %) are "collectible" z / cm y / cm E p = 29 GeV Emax SIS 100 acceptance separator/CR CR max. 13 Tm magnetic horn 0 < p pbar < 80 mrad

GSI Helmholtzzentrum für Schwerionenforschung GmbH Collectible pbars

GSI Helmholtzzentrum für Schwerionenforschung GmbH Collectible pbars: Self Absorption Cu:  pbar = 0.8 b p pbar

GSI Helmholtzzentrum für Schwerionenforschung GmbH Collectible pbars: MARS/FLUKA Cu:  pbar = 0.8 b p pbar

GSI Helmholtzzentrum für Schwerionenforschung GmbH Collectible pbars: MARS Cu:  pbar = 0.8 b p pbar

GSI Helmholtzzentrum für Schwerionenforschung GmbH Cu:  pbar = 8.8 b p pbar C:  pbar  =  0.42 b Collectible pbars: Graphite Surrounding

GSI Helmholtzzentrum für Schwerionenforschung GmbH pbar Yield: Collection efficiency of the magnetic horn yield = pbars in the ellipse primary protons

GSI Helmholtzzentrum für Schwerionenforschung GmbH pbar Yield: Cu vs Ir (8.92 vs g/cm³)

GSI Helmholtzzentrum für Schwerionenforschung GmbH pbar Yield: Comparison to CERN Data To injection orbit of collector ring: pbar/p = 2×10 -5 × 0.85 × 0.7 = 1.2×10 -5 Exp. data from CERN (Baird 1998) to injection orbit: pbar/p = 0.45×10 -5 × 1.5 = 0.7×10 -5 scattering losses in air / aluminum losses in separator / during injection correction for different energies and emmitances

GSI Helmholtzzentrum für Schwerionenforschung GmbH Summary For 1 antiproton in the CR 10 5 primary protons on the target are needed. I do not see room for significant improvements. All optimization steps* I can imagine are in the order of <20 %. * including a Li-lens instead of a horn