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Experiments with Radioactive Beams at GSI and FAIR

Experiments with Radioactive Beams at GSI and FAIR. Thomas Aumann. May 21st, 2010 10th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS NEW QUESTS IN NUCLEAR STRUCTURE VIETRI SUL MARE. * Modularized start version of FAIR - NuSTAR science with modules 0 to 3

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Experiments with Radioactive Beams at GSI and FAIR

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  1. Experiments with Radioactive Beams at GSI and FAIR Thomas Aumann May 21st, 2010 10th INTERNATIONAL SPRING SEMINAR ON NUCLEAR PHYSICS NEW QUESTS IN NUCLEAR STRUCTURE VIETRI SUL MARE * Modularized start version of FAIR - NuSTAR science with modules 0 to 3 - What is missing - Conclusion * Physics program on the way to FAIR Example: Quasifree scattering at R3B Single-particle structure of nuclei an N-N correlations

  2. FAIR Modularized Start Version Cost: 1027 M€ Available: 1039 M€ 104 M€ 19 M€ Modules 4 and 5 will be implemented as additional funds become available!

  3. FAIR Modularized Start Version Significant cost increases in civil construction and site development cost ( Germany pays additional 95 M€ for site specific costs) Modularized Start Version of FAIR A defined in White Paper Draft Module 0: Heavy-Ion Synchrotron SIS100 Module 1: Experiment hall at SIS100 for beam diagnostics, HADES/CBM, APPA, and detector calibration. Module 2: Super-FRS for NUSTAR including all three branches and the energy buncher Module 3: Antiproton facility for PANDA (LINAC; target, CR, HESR) and CR also for NuSTAR Module 4: LEB cave, NESR storage ring for NUSTAR und APPA, FLAIR building, cave for APPA Module 5: RESR storage ring for a higher beam intensity for PANDA and parallel operation with NUSTAR Cost 0-1-2-3: 1.027 M€ (2005) using updated civil construction cost and cost book values (CB 5.0) for accelerators Accepted available funds amount to 1.039 M€ (2005) another 62 M€ not firm + 12 M€ from Saudi Arabia (new partner) Construction schedule foresees readiness for installation end 2016

  4. Implementation Scenario for NuSTAR Experiments in Modules 0-3 DESPEC at MF-4 ?? HISPEC At LEB focus?? R3B ILIMA in CR MATS & LASPEC behind R3B ??

  5. NuSTAR Experiments Modules 0-3 (+ building for energy buncher) • HISPEC • full capability • MATS & LASPEC • full capability • DESPEC • full capability • R3B • full capability • Delays possible for • EXL in NESR (Module 4) • ILIMA in NESR (Module 4) • ELISe (FAIR B) • ILIMA • Isochronous mode • shortest-lived nuclei • limited precision

  6. R3B: reaction studies at the highest energies in complete kinematics  full R3B programme will be accessible (world-wide unique) few body correlations at and beyond the drip-lines in break-up reactions (halo nuclei, open quantum systems) dipole response below and above the particle threshold using Coulomb excitation and breakup (Pygmy response, neutron skins, neutron matter properties, EOS) Evolution of shell structure and single-particle occupancies using knock-out and quasi-free scattering experiments (tensor force, shell quenching) Nuclear dynamics in fission and the symmetry energy at supra-saturation density in fragmentation reactions (large scale collective motion EOS) Measurement of (gamma,n) reaction rates for r-process nuclei (origin of the heavy element) NuSTAR science within Modules 0-1-2-3

  7. NuSTAR science within Modules 0-1-2-3 DESPEC: decay spectroscopy using gamma-ray and neutron spectroscopy following isomeric or beta-decay of very exotic nuclei Experiments with production rates between 1000 per second and 1 per hour possible ( farthest reach towards the drip lines) Measurement of absolute Gamow Teller strength values Investigations of 100Sn and nuclei along/beyond the proton dripline Structure of nuclei in heavy r-process region Measurement of g-factors of isomeric states and half lives of very short isomers

  8. NuSTAR science within Modules 0-1-2-3 HISPEC: high resolution in-flight gamma-spectroscopy (HISPEC with AGATA) Probing the evolution of nuclear shell structure in very n-rich medium-heavy nuclei using Coulomb-excitation, knock-out, and secondary fragmentation Probing the evolution of nuclear collectivity far from stability using Coulomb-excitation, lifetime and g-factor measurements

  9. NuSTAR science within Modules 0-1-2-3 MATS and LASPEC: precision masses, ground-state moments short-lived nuclei and refractory elements not available with ISOL using ion-traps and laser spectroscopy after gas-stopping cell

  10. NuSTAR science within Modules 0-1-2-3 ILIMA in CR: direct mass measurements of nuclei with half-lives in the millisecond region (most exotic, r-process) half-life experiments on highly-charged exotic ions studies of long-lived isomeric states. Highlight: Half-lives and masses of r-process nuclei responsible for the A~195 abundance mass peak

  11. What is missing? NESR ELISe: Elastic and inelastic electron scattering (charge distributions, giant resonances) • Experiments with stored electron cooled ion beams • World-wide unique • Conceptionaly new AIC: Antiproton anihilation on nuclear surface (neutron skin thickness) EXL: Elastic scattering and low-q reactions (matter distributions, monople resonances, capture reactions, trnasfer, knock-out) • ILIMA: • precise masses and half-lives of many nuclei • unique decay modes

  12. Conclusions Modules 0-1-2-3 of FAIR will allow for unique, exciting, and world-unique experiments Modularized FAIR start version is an essential step towards establishing the FAIR GmbH However: NuSTAR experimental programme will bring to fruition only a fraction of its full potential Need for NESR with world-wide unique experimental Need RESR for availability of parallel beams at FAIR Need SIS300 for full multi-user capabilities and maximum efficiency of FAIR facility We need to continue to work towards the full FAIR facility!! Continue to work on TDRs for NuSTAR experiments Continue a vigorous program at GSI FRS and ESR

  13. The nucleus: single-particle motion in a mean field ? Deviation from the independent-particle picture: Correlations: Configuration mixing, Coupling to collective phonons Short-range correlations → high momenta → reduced single-particle strength (occupations, spectroscopic factors) Ingo Sick

  14. Spectroscopic factors for neutron-proton asymmetric nuclei Comparison e- induced knockout and knockout in inverse kinematics with light target (Be) Figure from Alexandra Gade, Phys. Rev. C 77, 044306 (2008)

  15. Spectroscopic factors for neutron-proton asymmetric nuclei weakly bound nucleons Figure from Alexandra Gade, Phys. Rev. C 77, 044306 (2008)

  16. Spectroscopic factors for neutron-proton asymmetric nuclei strongly bound nucleons weakly bound nucleons ? Origin unclear isospin dependence of correlations ? Figure from Alexandra Gade, Phys. Rev. C 77, 044306 (2008)

  17. Correlations in asymmetric nuclei and nuclear matter neutrons ρ = 0.32 fm−3 protons ρ = 0.16 fm−3 Subedi et al. Electron-induced knockout (JLab)

  18. Sensitivity of Coulomb and nuclear breakup Reaction probabilities Halo-Neutron Densities Coulomb breakup Overlap with continuum wave function Nuclear breakup Sensitivity to the tail of the wave function only Alternative approach: quasi-free scattering: (p,2p), (p,pn) etc. at LAND and R3B or (e,e'p) at the e-A collider at FAIR

  19. Future: Quasi-free scattering in inverse kinematics kinematical complete measurement of (p,pn), (p,2p), (p,pd), (p,a), .... reactions redundant experimental information: kinematical reconstruction from proton momenta plus gamma rays, recoil momentum, invariant mass sensitivity not limited to surface → spectral functions → knockout from deeply bound states cluster knockout reactions Measurement of proton recoils after knockout reactions with a CH2 target n,p, ... projectile Z,A Si, strip B CH2 target proton x, DE CsI, NaI

  20. box of DSSDs for proton tracking • polar angle coverage ≈ 15°≤  ≤ 80° • resolution: x ~ 100 m; E ~ 50 keV • range: 100 keV < E < 14 MeV • Crystal Ball detector • 162 20cm long NaI(Tl) crystals • additional low gain readout of forward 64 crystals • 4gammas • 2light particles Experimental Setup: LAND@Cave C Beam Target “New” Target Recoil Detector for Quasifree Scattering

  21. box of DSSDs for proton tracking • polar angle coverage ≈ 15°≤  ≤ 80° • resolution: x ~ 100 m; E ~ 50 keV • range: 100 keV < E < 14 MeV • Crystal Ball detector • 162 20cm long NaI(Tl) crystals • additional low gain readout of forward 64 crystals • 4gammas • 2light particles Experimental Setup: LAND@Cave C Beam Target “New” Target Recoil Detector for Quasifree Scattering

  22. Nucleus of interest Excited Fragment Evaporation A p,n,d,t,... A-1 q Photon(s) 2 Bound Proton Recoil q • Scattered Protons: •  opposite  angles • opening angle  90° 0 1 Free Target Proton Internal Momentum Separation Energy Quasifree Scattering with Exotic Nuclei:17Ne(p,2p)15O+p The two-proton Halo (?) nucleus 17Ne Pilot experiments with 12C, 17Ne and Ni isotopes already performed at the LAND-R3B setup are under analysis … Angular Correlations measured with Si-strip detectors for 17Ne(p,2p)15O+p ~180°, ~83° (sim. as for free pp scattering)

  23. Gamma Spectrum in Coincidence with 12C(p,2p)11B Reaction Channel Counts preliminary (MeV) Eγ inverse kinematics gamma spectrum after p knockout V. Panin et al. s proton knockout energy spectrum from invariant mass analysis M. Yosoi, PhD Thesis, 2003, Kyoto University

  24. Quasi-free cluster knockout Experiment S174: Proton elastic scattering (P. Egelhof et al.) Momentum distribution 6He + p → a + p' + X Spectroscopic factors: neutron: 1.7(2) alpha: 0.8(1) L. Chulkov et al., NPA 759(2005) 43

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