12/17/20151NuPECC Meeting - BentleyOverview Gamma-ray Spectroscopic Studies of Exotic Nuclei: Towards NuSTAR Mike Bentley (University of York, UK) Gamma-ray Spectroscopic Studies of Exotic Nuclei: Towards NuSTAR Mike Bentley (University of York, UK) Outline: UK role in NuSTAR at FAIR Physics Highlights in “pre-cursor” fragmentation campaigns Towards NuSTAR Outline: UK role in NuSTAR at FAIR Physics Highlights in “pre-cursor” fragmentation campaigns Towards NuSTAR

NUclear STructure Astrophysics and Reactions What are the limits for existence of nuclei? Where are the proton and neutron drip lines situated? Where does the nuclear chart end? How does the nuclear force depend on varying proton-to-neutron ratios? What is the isospin dependence of the spin-orbit force? How does shell structure change far away from stability? How to explain collective phenomena from individual motion? What are the phases, relevant degrees of freedom, and symmetries of the nuclear many-body system? How are complex nuclei built from their basic constituents? What is the effective nucleon-nucleon interaction? How does QCD constrain its parameters? Which are the nuclei relevant for astrophysical processes and what are their properties? What is the origin of the heavy elements? FAIR 12/17/2015 2NuPECC Meeting - Bentley

Towards a predictive (and unified) description of nucleiOverview 12/17/2015 3NuPECC Meeting - Bentley

What is NuSTAR? Project launched on November 7, 2007 The FAIR/NuSTAR facility FAIR 12/17/2015 4NuPECC Meeting - Bentley

FAIR 12/17/2015 5NuPECC Meeting - Bentley Key features: High intensity High Energy High Purity

NuSTAR – UK role SpokespersonDeputyOther R3BGermanySwedenUK Technical chair HISPECUKGermanyUK PRESPEC spokesperson DESPECSpainUKUK RISING spokesperson LASPECUKGermany MATSGermanyFinland EXLUKGermany ILIMAUKGermany ELISEGermanyRussia AICGermanyAustria Super FRSGermany NUSTAR BOARDChair: UK, Germany, Germany, France, Spain 12/17/2015 6NuPECC Meeting - Bentley Funding update: UK committed to funding for NuSTAR and PANDA at FAIR NuSTAR: £11M from Research Councils + Universities

12/17/2015 NuPECC Meeting - Bentley7 Physics with Fragmentation Beams In-beam spectroscopy RISING – fast beam PRESPEC – fast beam Decay spectroscopy RISING – stopped beam PRESPEC – stopped beam Reaction Spectroscopy ALADIN-LAND Towards NuSTAR GSI) 2014 Present

K-electrons L-electrons T1/2 = 10.4 s 205 Au Pt N=Z Proton-Rich Decay Spectroscopy 12/17/2015 8NuPECC Meeting - Bentley

RISING Rare Isotopic Spectroscopic GSI = 15 x Cluster germaniums for (the most) exotic gamma-ray spectroscopy Example: RISING at GSI 12/17/2015 9NuPECC Meeting - Bentley

Chemically independent production mechanism for secondary radioactive beams. Time of flight from production to stopper ~x00ns. Some ions transmitted in metastable states. Fragment Separator (FRS) Focal Pane ID Stopped RISING Stopped-beam RISING at GSI 12/17/ NuPECC Meeting - Bentley See, e.g. Regan et al, Nucl. Phys. A 787 (2007) 491

Warner, Bentley, Van Isacker, NATURE Phys 2 (2006) 311. ISOSPIN Symmetry 12/17/ NuPECC Meeting - Bentley

12/17/2015 NuPECC Meeting - Bentley12 D.Rudolph et al, Phys. Rev. C78 (Rap. Comm) (2008) Ni spectroscopy at RISING Delayed Gamma-rays after implantation 550 MeV/u 58 Ni fragmented on 1g/cm 2 Be target

Ni spectroscopy at RISING D.Rudolph et al, Phys. Rev. C78 (Rap. Comm.) /17/ NuPECC Meeting - Bentley PRL 97 (2006)

Observed A=54 MED Expected MED (2 holes) Decreasing overlap of two nucleons coupled to increasing spin J Charge Symmetry Breaking – spin dependence (J=2 Anomaly) 12/17/2015 NuPECC Meeting - Bentley14 The J=2 Anomaly A=54 MED Gadea et al, Phys. Rev. Lett 97 (2006) Warner, Bentley, Van Isacker, NATURE Physics 2 (2006) 311. D.Rudolph et al, Phys. Rev. C78 (2008) (R)

Spectroscopy of odd-odd N=Z nuclei: RISING at GSI 12/17/ NuPECC Meeting - Bentley A.B.Garnsworthy et al, Phys. Lett. B 600 (2008) MeV/u 107 Ag fragmented on 4g/cm 2 Be target

12/17/ NuPECC Meeting - Bentley Spectroscopy of odd-odd N=Z nuclei: RISING at GSI

A.B. Garnsworthy et al., Phys. Lett. B660, 326 (2008) 12/17/ Spectroscopy of odd-odd N=Z nuclei: RISING at GSI NuPECC Meeting - Bentley

K-electrons L-electrons T1/2 = 10.4 s 205 Au Pt T 1/2 Weiss (E3 (94) ) = 7.49 s T 1/2 Weiss (M4 (921) ) = 10.6 s K-electrons L-electrons T 1/2 =10.4 s E  (exp) (11/2 -  3/2 + ) = 912 keV 204 Pt Au 126 N=82 N=126 12/17/ NuPECC Meeting - Bentley

Assumption of N=82 and N=126 shell quenching leads to a considerable improvement in the global abundance fit in r- process calculations r-process abundances mass number A exp. pronounced shell gap shell structure quenched information on excited states essential!! Quenching of N=82 and N=126 gaps? 12/17/201519NuPECC Meeting - Bentley

Within red line: nuclei populated and measured by RISING. 205 Au Experiment led by Zs. Podolyák, Surrey 204 Pt ? Decay Spectroscopy around N=126 gap: RISING 208 Pb at 1 GeV/u on 2.5 g.cm 2 Be target 12/17/ NuPECC Meeting - Bentley

S.Steer et al. submitted to PRL, Mar. 08 Decay Spectroscopy around N=126 gap: RISING 12/17/ NuPECC Meeting - Bentley

Observation of isomers -> change in shell-model parameters Decay Spectroscopy around N=126 gap: RISING 12/17/ NuPECC Meeting - Bentley

Decay spectroscopy (DESPEC) Energy buncher / spectrometer In-flight spectroscopy (HISPEC) Decay Spectroscopy at NuSTAR: DESPEC 12/17/ NuPECC Meeting - Bentley

r-process nucleosynthesis Nuclear Astrophysics  -delayed neutron decay Nuclear Structure  -delayed proton decay Fundamental symmetries high spin isomeric decay  -decay spectroscopy Gamov-Teller quenching superallowed Fermi transitions , , ,p, n detection and spectroscopy: lifetimes, energies, strengths, spins  and p  and n Decay Spectroscopy at NuSTAR: DESPREC 12/17/ NuPECC Meeting - Bentley

25 NSCL Experiment #5117, March 2007 – Bentley et al × 10 6 pps (70% 56 Ni) 188 mg/cm 2 Be 10pnA 58 Ni 600 mg/cm2 Be target S800 Spectrograph In-beam Spectroscopy: Fragmentation at MSU

12/17/2015 NuPECC Meeting - Bentley26 S800 – Fragment ID Z A/Q Drip line J.R. Brown et al. (YORK) in prep (2008) In-beam Spectroscopy: Fragmentation of 56 Ni

12/17/2015 NuPECC Meeting - Bentley27 First spectrsocopy of N=Z-3 nuclei above 33 Ar 53 Mn 53 Ni 49 V 49 Fe J.R. Brown et al. (YORK) in prep (2008) SeGA in-beam Gamma-ray spectra In-beam Spectroscopy: N=Z-3 Nuclei 53 Ni, 49 Fe

12/17/2015 NuPECC Meeting - Bentley28 J.R. Brown et al. (YORK) in prep (2008) In-beam Spectroscopy: N=Z-3 Nuclei 53 Ni, 49 Fe Energy Difference (keV) Strong evidence for J=2 Anomaly...

Decay spectroscopy (DESPEC) Energy buncher / spectrometer In-flight spectroscopy (HISPEC) In-beam Spectroscopy at NuSTAR: HISPEC 12/17/ NuPECC Meeting - Bentley

 Coulomb excitation  Knock out ractions  Fragmentation  Multiple Coulomb excitation  Transfer reactions  Inelastic reactions  Fusion reaction Rare Isotope Beams of all elements Relativistic Beams  100 MeV/u Super-FRS, low energy buncher Beam: T 1/2 ≤ 200 ns,  E  % Fast slowed down beams 3-20 MeV/u Super-FRS, low energy buncher Beam: T1/2 ≤ 200 ns,  E  %, beam tracking required Brilliant low energy beams 3-20 MeV/u Super-FRS, NESR, transfer line Beam: T1/2 > 5 s,  E  0.01 %, I lim ≤10 7 /s isomer beams High Resolution In-beam SPECtroscopy: HISPEC 12/17/ NuPECC Meeting - Bentley

Reactions in complete kinematics Neutrons High Resolution measurement Heavy fragments Protons Large acceptance dipole Target Tracker Calorimeter RIB Reactions with Relativistic Radioactive Beams: R 3 B 12/17/ NuPECC Meeting - Bentley

Unique capability to investigate fundamental aspects of isospin asymmetric nuclei and nuclear matter High-energy RIBs (200 – 2000 A.MeV) Structure of asymmetric nuclei modification of independent particle model correlations in nuclei new collective modes Bulk properties of asymmetric nuclear matter nuclear EOS density dependence of symmetry energy in-medium NN cross-sections neutron skin  core vibration Reactions with Relativistic Radioactive Beams: R 3 B 12/17/ NuPECC Meeting - Bentley

The Nuclear Equation of State (EOS) Relationship between pressure, density and temperature of nuclear matter Intrinsic interest in understanding matter in extreme states Key to understanding compact astrophysical objects: supernovae, neutron star structure, binary neutron star systems, coalescing binary neutron stars, etc. Strong synergy with Gravitational Wave projects such as Advanced LIGO/GEO600 – highest priority STFC astroparticle physics projects Strong synergy with studies of the Partonic Equation of State and the Quark Gluon Plasma, e.g. ALICE at LHC P. Danielewicz et al., Science 298, 1592 (2002). EOS = symmetric (N=Z) EOS + asymmetric (N≠Z) EOS Significant constraints on symmetric EOS from terrestrial experiments, e.g. heavy-ion collisions, nuclear structure. Very little known about asymmetric EOS, N.B. a neutron star consists of highly asymmetric matter – asymmetric EOS crucial FAIR will provide unique opportunity to study the asymmetric EOS using radioactive ion beams 12/17/ NuPECC Meeting - Bentley

Summary Gamma-ray spectroscopy of Exotic nuclei through projectile fragmentation... Proton-rich: Limits of nuclear stability, breakdown of isospin symmetry, exotic decay modes Neutron-rich: Evolution and quenching of shell gaps Current experiments pave the way for NuSTAR Thanks to: GSI (RISING Community) MSU (Glasmacher, Gade, Bazin et al) HISPEC/DESPEC Community Paddy Regan, Zsolt Podolyak (Surrey) 12/17/ NuPECC Meeting - Bentley