Precision Experiments with Exotic Nuclei at Relativistic Energies

1. Precision Experiments with Exotic Nuclei at Relativistic Energies Hans Geissel, GSI and JLU Giessen • Introduction • Precision Measurements: a) with the Magnetic Spectrometer (FRS) b) with the Storage Ring (ESR) • Super-FRS, the Next-generation Facility

2. ISOL and In-FLight Facilities in Europe Björn Jonson (2000)

3. Kinematics of Projectile Fragmentation and Fission

4. Secondary Nuclear Beam Facility at GSI FRS: In-flight Separator & High-Resolution Spectrometer 3 1 SIS 2 • Decay Spectroscopy, • High-resolution momentum measurements • Masses, Lifetimes, Direct Reactions, • Isomeric Beams • Reactions Studies (Complete Kinematics)

5. Advantages of Projectile Fragmentationand – Fission at Relativistic Energies (0.5-1GeV/u) High luminosity Thick targets ( 5 g/cm2 ) In -flight separation Time limit 200 ns  T1/2, q=Z Single-atom spectroscopy (pb range) Mono-isotopic beams of all elements Cocktail beams, optional Kinematic focusing Injection into storage rings Full solid angle coverage Complete kinematics reaction experiments Simple reaction Sudden approach mechanism Glauber model G. Münzenberg Ann. Rev. Nucl. Part. Sc. 45

6. The FRS as an Energy-Loss Spectrometer Incident energy shifts do not show up at the final focus E01,E02,E03 E01,E02,E03 Target E1 E2 E3

7. The Projectile Fragment Separator FRS

8. W. Schwab et al. Z. Phys. A350, 283 8B + C 7Be 1500 MeV/u 12C 7Be Nuclear Structure via Precise Momentum Measurements at Relativistic Energies Knockout Reactions lead to Discovery of Halo-Nuclei 12C + Be 8B P.G. Hansen, B. Jonson Eur. Phys. Lett. 4 (1987) 409 I. Tanihata et al., Phys. Rev. Lett. 55 (1985) 2676 1000 MeV/u 12C 8B Target

9. 8B 7gBe 87% 13% Spectroscopic factors D. Cortina-Gil et al. Phys. Lett. B529 (2002) 36 Halo Studies: Momentum Measurements in Coincidence with Gamma Ray Emission 7Be* . GSI and MSU Data P.G. Hansen 2004

10. Experimental Facilities Monoisotopic Fragment BeamsStored in the ESR

11. Schottky Mass Spectrometry Isochronous Mass Spectrometry Precision Mass Measurements in the ESR

12. New and Reference Masses in the same Spectrum High Resolution and Sensitivity accuracy: 30 keV Schottky Mass Spectrometry 950 MeV/u 209Bi + Be  Projectile Fragments

13. noise power density a.u. frequency [Hz] Decay of Single Atoms Stored in the ESR Yu. Litvinov

14. Results compared with Theory srms = 650 keV S. Goriely et al. PR C66 2002

15. Predictive Power of the Relativistic Mean Field Model (RMF) G.A. Lalazissis et al. ADNDT 71 (1999)1 even-even nuclei, NL3, srms= 2.6 MeV srms = 3831 keV Yu. Litvinov

16. 207Tl81+ 207Tl81+ 207mTl81+ 207Pb81+ 207mTl81+ 207Pb81+ Lifetime Measurements of Short-lived Nuclei Applying Stochastic and Electronic Cooling Bound-state Beta-Decay of 207Tl81+

17. Lifetime Measurements of 207mTl • Shorter cooling time allowed to see isomeric state of 207Tl (E* = 1348 keV, half-life of 1.33 ± 0.11 s for neutral atom) • Measured half-life of bare nuclei, transformed in the rest frame:

18. Half-life Measurements of 207Tl81+ Bound-state Beta Decay D. Boutin, PhD

19. 8B Key-Results from FRS Experiments Advantages of High Energies NP A665 (2000) 221 New Fission Studies NP A667 (2000) 75 New Mass Measurements PR C65 (2002)064603 EPJ A14 (2002) 279 100Sn 2-p Radioactivity PRL 86 (2001) 5442 Bound-state b--decay Giant Dipole Resonance to be published Pionic Atoms PRL 88 (2002) 122301 NP A720 (2003) 3 New Fission Fragments 78Ni PL B 444 (1998) 32 Halo Nuclei Shells far off Stability 11Li Skin Nuclei PRL 91 (2003) 162504

20. FAIR: The International Accelerator Facilityfor Beams of Ions and Antiprotons NuSTAR Facility

21. Layout of the Super-FRS Design Parameters The main technical challenges are at the Pre-Separator

22. Experiments withLow-energy andStopped beams  Laser spectroscopy  Decay spectroscopy  Ion and atom traps

23. The high-energy branch of the Super-FRS: Reactions with Relativistic Radioactive Beams The setup • Goals: • identification, tracking and momentum measurement, Dp/p ~10-4 • exclusive measurement of the final state: • - coincident measurement of neutrons, protons, gamma-rays, light recoil particles • applicable to a wide class of reactions

24. CR NESR RESR Future Super-FRS ELISe Gas target ILIMA EXL

25. Why light-ion scattering ? - select specific spin-isospin transitions ! - transition form factor sensitive to multipolarity ! - low nuclear absorption ! Why in a storage ring ? - information on form factor at low momentum transfer  very thin (windowless) target  gain luminosity ! beam cooling beam recirculation (NESR ~ 106 s-1)  high resolution (recoil kinematics) negligible straggling effects in target and electron cooling EXotic nuclei studied in Light-ion induced reactions at the NESR storage ring (EXL) Elastic (p,p) , (a,a) … Inelastic (p,p’), (a,a’) ... Transfer (d,p), (p,t) … Charge exchange (3He,t), … Quasi-free (p,2p), (p, pa) … ~ 0.1 …. 0.8 GeV/u Key issues: matter distribution (halo,skin) shell structure nn correlations, cluster new collective modes r-, rp-process (GT, capture..) in-medium interactions in asymmetric and low-density matter

26. Summary • Studies of exotic nuclei will contribute significantly to the basic knowledge of matter. • Precision experiments with stored exotic nuclei open up a new field for nuclear structure physics and astro-physics. • The next–generation facility will present unique conditions for research and education. • There are many technical challenges inviting especially also the next-generation scientists.

27. Let us move to the common future of NuSTAR Physics at FAIR! www.gsi.de/nustar