12/17/20151NuPECC Meeting - BentleyOverview Gamma-ray Spectroscopic Studies of Exotic Nuclei:...

04/22/23 1NuPECC Meeting - Bentley

OverviewOverview

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 ReactionsWhat 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?

NuSTAR @ FAIRNuSTAR @ FAIR


What is NuSTAR?

Project launched on November 7, 2007

The FAIR/NuSTAR facilityNuSTAR @ FAIRNuSTAR @ FAIR


NuSTAR @ FAIRNuSTAR @ FAIR


Key features:High intensityHigh EnergyHigh Purity

NuSTAR – UK roleNuSTAR – UK roleSpokesperson Deputy Other

R3B Germany Sweden UK Technical chair

HISPEC UK Germany UK PRESPEC spokesperson

DESPEC Spain UK UK RISING spokesperson

LASPEC UK Germany

MATS Germany Finland

EXL UK Germany

ILIMA UK Germany

ELISE Germany Russia

AIC Germany Austria

Super FRS Germany Germany

NUSTAR BOARD

Chair: UK, Germany, Germany, France, Spain04/22/23 6NuPECC Meeting - Bentley

Funding update:UK committed to funding for NuSTAR and

PANDA at FAIRNuSTAR: £11M from Research Councils +

Universities

04/22/23 NuPECC Meeting - Bentley 7

Physics with Fragmentation Beams

Towards NuSTAR (@ GSI)Towards NuSTAR (@ GSI)

2014

Present

K-electrons

L-electrons

T1/2 = 10.4 s205Au126

202Pt

N=Z

Proton-Rich Decay Spectroscopy


RISING

Rare Isotopic Spectroscopic

INvestigations @ GSI =

15 x Cluster germaniums for

(the most) exotic gamma-ray

spectroscopy

Example: RISING at GSIExample: RISING at GSI


• 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 GSIStopped-beam RISING at GSI


See, e.g. Regan et al, Nucl. Phys. A 787 (2007) 491


D.Rudolph et al, Phys. Rev. C78 (Rap. Comm) (2008) 021301

5454Ni spectroscopy at RISINGNi spectroscopy at RISING

Delayed Gamma-rays after implantation

550 MeV/u 58Ni fragmented on 1g/cm2 Be target

28 26 26 28

5454Ni spectroscopy at RISINGNi spectroscopy at RISING

D.Rudolph et al, Phys. Rev. C78 (Rap. Comm.) 2008 021301


PRL 97 (2006) 152501

Observed A=54 MEDExpected MED (2 holes)

Decreasing overlap of two nucleons coupled to increasing spin J

Charge Symmetry Breaking – spin dependence (J=2 Anomaly)


The J=2 AnomalyThe J=2 Anomaly

A=54 MED Gadea et al, Phys. Rev. Lett 97 (2006)

152501

Warner, Bentley, Van Isacker, NATURE Physics 2 (2006) 311.

D.Rudolph et al, Phys. Rev. C78 (2008) 021301(R)

Spectroscopy of odd-odd N=Z nuclei: RISING at GSISpectroscopy of odd-odd N=Z nuclei: RISING at GSI


A.B.Garnsworthy et al, Phys. Lett. B 600 (2008) 326

750 MeV/u 107Ag fragmented on 4g/cm2

Be target

A.B. Garnsworthy et al., Phys. Lett. B660, 326 (2008)

04/22/23 17


NuPECC Meeting - Bentley

K-electrons

L-electrons

T1/2 = 10.4 s205Au126

202Pt

T1/2Weiss(E3(94)) = 7.49 s

T1/2Weiss(M4(921)) = 10.6 s

K-electrons

L-electrons

T1/2=10.4 s

E(exp)(11/2-3/2+) = 912 keV

204Pt126

205Au126

N=82N=126


Assumption of N=82 and N=126 shell quenching leads to a considerable improvement in the global abundance fit in r-process calculations

r-pr

oces

s ab

unda

nces

mass number A

exp.pronounced shell gapshell structure quenched

information on excited states essential!!

Quenching of N=82 and N=126 gaps?Quenching of N=82 and N=126 gaps?


Within red line: nuclei populated and measured by RISING.

205Au

Experiment led by Zs. Podolyák, Surrey

204Pt

?

Decay Spectroscopy around N=126 gap: RISINGDecay Spectroscopy around N=126 gap: RISING208Pb at 1 GeV/u on 2.5 g.cm2 Be target


S.Steer et al. submitted to PRL, Mar. 08

Decay Spectroscopy around N=126 gap: RISINGDecay Spectroscopy around N=126 gap: RISING


Observation of isomers ->

change in shell-model parameters

Decay Spectroscopy around N=126 gap: RISINGDecay Spectroscopy around N=126 gap: RISING


Decay spectroscopy(DESPEC)

Energy buncher /spectrometer

In-flight spectroscopy (HISPEC)

Decay Spectroscopy at NuSTAR: DESPECDecay Spectroscopy at NuSTAR: DESPEC


• 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: DESPRECDecay Spectroscopy at NuSTAR: DESPREC


NuPECC Meeting - Bentley 25

NSCL Experiment #5117, March 2007 – Bentley et al

0.5 -1.0 × 106 pps (70% 56Ni)

188 mg/cm2 Be

10pnA 58Ni

600 mg/cm2 Be target

S800 Spectrograph

In-beam Spectroscopy: Fragmentation at MSUIn-beam Spectroscopy: Fragmentation at MSU


S800 – Fragment ID

Z

A/Q

Drip line

J.R. Brown et al. (YORK) in prep (2008)

In-beam Spectroscopy: Fragmentation of In-beam Spectroscopy: Fragmentation of 5656NiNi


First spectrsocopy of N=Z-3 nuclei

above 33Ar

53Mn

53Ni

49V

49Fe


SeGA in-beam Gamma-ray

spectra

In-beam Spectroscopy: N=Z-3 Nuclei In-beam Spectroscopy: N=Z-3 Nuclei 5353Ni, Ni, 4949FeFe



In-beam Spectroscopy: N=Z-3 Nuclei In-beam Spectroscopy: N=Z-3 Nuclei 5353Ni, Ni, 4949FeFe

Ener

gy D

iffer

ence

(keV

)

Strong evidence for J=2 Anomaly...

Decay spectroscopy(DESPEC)

Energy buncher /spectrometer

In-flight spectroscopy (HISPEC)

In-beam Spectroscopy at NuSTAR: HISPECIn-beam Spectroscopy at NuSTAR: HISPEC


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/uSuper-FRS, low energy buncherBeam: T1/2 ≤ 200 ns, E 0.1-0.3 %

Fast slowed down beams 3-20 MeV/uSuper-FRS, low energy buncherBeam: T1/2 ≤ 200 ns, E 10-30 %, beam tracking required

Brilliant low energy beams 3-20 MeV/uSuper-FRS, NESR, transfer lineBeam: T1/2 > 5 s, E 0.01 %, Ilim≤107/s

isomer beams

HHigh Resolution igh Resolution IIn-beam n-beam SPECSPECtroscopy: troscopy: HISPECHISPEC


Reactions in complete kinematics

Neutrons

High Resolution measurement

Heavy fragments

Protons

Largeacceptancedipole

• Target• Tracker• Calorimeter

RIB

Reactions with Relativistic Radioactive Beams: RReactions with Relativistic Radioactive Beams: R33BB


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: RReactions with Relativistic Radioactive Beams: R33BB


SummarySummary

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)


12/17/20151NuPECC Meeting - BentleyOverview Gamma-ray Spectroscopic Studies of Exotic Nuclei:...

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