experiments with radioactive beams at gsi and fair
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
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
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!
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
Implementation Scenario for NuSTAR Experiments in Modules 0-3
R3B
DESPECat MF-4 ??
HISPECAt LEB focus??
MATS & LASPECbehind R3B ??
ILIMA in CR
NuSTAR Experiments Modules 0-3
ILIMA• Isochronous mode • shortest-lived nuclei• limited precision
R3B • full capability
DESPEC• full capability
HISPEC• full capability
MATS & LASPEC• full capability
Delays possible for • EXL in NESR (Module 4)• ILIMA in NESR (Module 4)• ELISe (FAIR B)
(+ building for energy buncher)
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
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
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
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
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
What is missing?
NESR
ILIMA:• precise masses and half-lives of many nuclei• unique decay modes
ELISe:Elastic and inelastic electron scattering(charge distributions, giant resonances)
EXL:Elastic scattering and low-q reactions(matter distributions, monople resonances, capture reactions, trnasfer, knock-out)
Experiments with stored electron cooled ion beams• World-wide unique• Conceptionaly new
AIC:Antiproton anihilation on nuclear surface(neutron skin thickness)
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
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)
The nucleus: single-particle motion in a mean field ?
Ingo Sick
Spectroscopic factors for neutron-proton asymmetric nuclei
Figure from Alexandra Gade, Phys. Rev. C 77, 044306 (2008)
Comparison e- induced knockout and
knockout in inverse kinematics with light target (Be)
Spectroscopic factors for neutron-proton asymmetric nuclei
weakly bound nucleons
Figure from Alexandra Gade, Phys. Rev. C 77, 044306 (2008)
Spectroscopic factors for neutron-proton asymmetric nuclei
strongly bound nucleons
?
Origin unclear
isospin dependence of correlations ?
Figure from Alexandra Gade, Phys. Rev. C 77, 044306 (2008)
weakly bound nucleons
Correlations in asymmetric nuclei and nuclear matter
Subedi et al.
protons
neutrons
ρ = 0.32 fm−3
ρ = 0.16 fm−3
Electron-induced knockout (JLab)
Sensitivity of Coulomb and nuclear breakup
Reaction probabilities
Coulomb breakup
Overlap with continuum wave function
Halo-Neutron Densities
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
Nuclear breakup
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
x, Eproton
CsI, NaI
Si, stripCH2 target
projectile Z,AB
n,p, ...
Experimental Setup: LAND@Cave C
Beam
Target
• 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
“New” Target Recoil Detector for Quasifree Scattering
Experimental Setup: LAND@Cave C
Beam
Target
• 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
“New” Target Recoil Detector for Quasifree Scattering
Quasifree Scattering with Exotic Nuclei:17Ne(p,2p)15O+p The two-proton Halo (?) nucleus 17Ne
Nucleus of interest Excited Fragment
A
A-1
Free Target Proton
Recoil q
Photon(s)
Bound Proton
Separation Energy
0121 TTTTE AS
Internal Momentum
0211 ppppq A
q
p,n,d,t,...
Evaporation
0
1
2
Scattered Protons:
• opposite angles• opening angle 90°
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)
Gamma Spectrum in Coincidence with 12C(p,2p)11B Reaction Channel
M. Yosoi, PhD Thesis, 2003, Kyoto University
preliminary
Eγ(MeV)
Cou
nts
inverse kinematics
gamma spectrum after p knockout
s proton knockout
energy spectrum from invariant mass analysis
V. Panin et al.
Quasi-free cluster knockout
L. Chulkov et al., NPA 759(2005) 43
6He + p → + p' + XMomentum distribution
Experiment S174: Proton elastic scattering (P. Egelhof et al.)
Spectroscopic factors:
neutron: 1.7(2)
alpha: 0.8(1)