Perspectives for Nuclear Spectroscopy at the UNILAC

1. Perspectives forNuclear Spectroscopy at the UNILAC J. Gerl, M. Gorska GSI Darmstadt, Germany UNILAC Workshop GSI 22.8.2016

2. 15 Focus of GS: Spectroscopy employing RIBs at SIS/FRS VEGA - RISING – PRESPEC – HISPEC/DESPEC • Nuclear Shell structure • N ≈ Z • N>>Z • Nuclear shapes • Quadrupole, Octupole, Triaxiality • Shape transitions • High K-isomers • Collective modes • N>>Z : GDR soft mode • Nuclear Symmetries • mirror-isospin, pn-pair correlation Nuclear astrophysics • r, rp process Relativistic Coulomb excitation, Fragmentation and Decay studies using Rare Isotope Beams and high-resolution  Spectroscopy

3. 15 Complementary Experiments at UNILAC • Nuclear Shell structure • N ≈ Z • N>>Z • Nuclear shapes • Quadrupole, Octupole, Triaxiality • Shape transitions • High K-isomers • Collective modes • N>>Z : GDR soft mode • Nuclear Symmetries • mirror-isospin, pn-pair correlation Nuclear astrophysics • r, rp process Multiple Coulomb excitation, Transfer, Deep inelastic reactions, Fusion evaporation, Fission and Decay studies using Stable Isotope Beams and high-resolution  Spectroscopy

4. 15 100Sn as example for multitude of techniques • Fusion symmetric reaction EXOGAM, EUROBALL, GASP.. + Ancillaries - in-beam MSEPat GSI - β decay - spin-gap isomers Argonne/OakRidge - α-decay • Fragmentation GSI, RIBF, NSCL, GANIL - Coulex -Transfer - Isomers - β decay

5. 15 Spin gap and seniority isomers below N = Z = 50 with RISING and GSI - ISOL • proton – neutron hole-hole interaction in pn g9/2-n • core excitation in large-scale SM in pn g9/2-1 (d5/2 ,g7/2)1 Fusion evaporation reactions best to avoid missing isomers!

6. 15 NUSTAR instrumentationforspectroscopy HISPEC -LYCCA heavy ioncalorimeterwithToFcapabilityin operation -AGATA gammaspectrometerin operation -Hyde light particlearrayprototype -NEDA Neutron detectorarrayprototype -EDAQ dedicatedelectronicsand DAQ based on severalbranches DESPEC -AIDA activeimplantationdeviceprototype -MONSTER neutronToFarrayunderconstruction -BELEN neutrondetecionarrayin operation -DTASDecay Total Absorption Spectrometerin operation -DEGAS Ge Array gammaspectrometerin development -FATIMA Fast timingarrayin operation -EDAQ dedicatedelectronicsand DAQ based on severalbranches

7. 15 DEGAS DetectorRealization TDR approved in 7.2015 Design work finished scrutinizedby IFIN-HH Ge Array with 28 Triples Holding bars Connectors Top Deck (Support electronics, power supply and µPC) Middle deck (Ge-PA + HV) Bottom Deck (BC electronics, later Ge-DAQ) Backcatcher Crystal capsule HPGe Crystal Pre-series construction started Funding: Phase I 100% secured Phase II 80% secured

8. 15 Example: Isomerism in 94Pd • Reaction: 40Ca (~170 MeV) + 58Ni (>2 mg/cm2) -> 2p2n + 94Pd • DEGAS+NEDA+FATIMA • Time differencebetween two coincident γ rays detected in FATIMAγ ray(s) in DEGASand a 2n gate in NEDA Total cross section ~1b Interesting exit channel ~1μb Particle selection

9. 15 Typical fusion evaporation cross section distributions Narrow resonances eg. 104Sn: Ebeam = 3.6-4.4 MeV/u 50Cr + 58Ni -> 108Te* Tunable beam energy required

10. 15 At the catcher: εp~55% εα~10% εn~25% εγ~3.5% Prompt and delayed spectroscopy in 98Cd 58Ni + 46Ti → 104Sn* → 98Cd + α2n 8+ 2428 6+ 2281 2083 4+ 1395 2+ 0+ 0 M.Górska et al., Phys. Rev. Lett. 79 (1997) 2415 R. Grzywacz et al., ENAM 98 AIP CP 455 (1998) 430 Similar set-up needed at X7

11. 15 Example: Lifetime of heavy nuclei • Evolution ofcollectivity in heavy nuclei •  transferreaction • e.g. 12C(204Pb, 208Po)8Be • Ebeam = 5.9 MeV/u M. Reese, GSI

12. 15 Spin-oriented isomers probing nuclear moments Pulsed beam – nuclear reaction on target – TDPAD (Time Dependent Perturbed Angular Distribution) of  rays H. Watanabe, RIKEN

13. 15 Example: g-factors from isomer decays H. Watanabe, RIKEN

14. 15 Requirements for Gamma spectroscopy at UNILAC • Prompt measurements: • broad range of beam isotopes • exactly tunable beam energy (3-7 MeV/u) • long pulses (DC beam) • high duty cycle • moderate intensities • broad range of targets • Fusion evaporation, Deep inelastic, Transfer, multiple Coulex • Delayed measurements: • broad range of beam isotopes • exactly tunable beam energy (3-7 MeV/u) • short pulses possible • moderate to high duty cycle • moderate to high intensities • broad range of targets • Fusion evaporation, Deep inelastic, Fission

15. 15 Gamma Spectroscopy Programme at UNILAC • Complementary to HISPEC/DESPEC runs at GSI/FRS and FAIR/Super-FRS • Requested beam time: 4-8 weeks/a • Location: X7 cave (SHIP, TASCA in collab. with SHE groups) • Instrumentation: Detectors from HISPEC/DESPEC (in the 11 months/a without RIB availability) • Attractive for the NUSTAR physics community Substabtial addition to scientific output of nuclear spectroscopy at GSI