Transcript Rauno Julin

LRP2010 - WG3
Nuclear structure and dynamics
WG3 Members
Navin Alahari
Thomas Aumann
Yorick Blumenfeld
Peter Butler
Hans Fynbo
Andres Gadea
Wolfram Korten
Adam Maj
Gerda Neyens
Thomas Nilsson
Robert Roth
Patricia Roussel-Chomaz
Christoph Scheidenberger
Andrea Vitturi
Dario Vretenar
Convener: Rauno Julin
NuPECC Liaisons: Angela Bracco, Maria Borge
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Convener’s guideline:
Focus on the future ideas !
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The main Chapters of the WG3 draft
•
Introduction
•
Theoretical aspect
•
Onset of complexity
•
Shell structure and isospin degree of freedom
•
Superheavy elements
•
Collective properties
•
Reaction dynamics
•
Ground-state properties
•
Facilities and instrumentation
•
Recommendations
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Introduction
Nuclear structure physics
• Probing of a rich variety of quantum phenomena …
… and even more in the untouched 6000 nuclei
• Diverse field
• Need a diverse set of tools,
both theoretical and experimental
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Introduction
Key questions
 How can we describe the rich variety of low-energy structure
and reactions of nuclei in terms of the underlying fundamental
interactions between individual particles?
 How can we predict the evolution of nuclear collective and
single-particle properties as functions of mass and isospin,
angular momentum and temperature?
 What are the relevant low-energy degrees of freedom
that govern nuclear dynamics?
 How do regular and simple patterns emerge
in the structure of complex nuclei?
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Theoretical aspect
 Ab Initio methods
 Shell model
 Energy density functional methods
 Symmetries in nuclei and phase transitions
 Reactions
 Toward a unified description
of nuclear structure and reactions
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Theoretical aspect
BOX example:
THEORY and EXPERIMENT
Modern approaches in nuclear theory aim at an ab-initio
understanding of nuclear structure and reactions. Realistic
effective interactions emerge from chiral interactions with 2and 3-body forces. Many-body methods have lead to a
consistent microscopic description of light nuclei using
nucleons as degrees of freedom. These yield shell structure,
clusters, halos, resonances, capture and transfer reactions
and scattering states in a unified picture. The obtained
understanding can be tested by experiments, which probe
excitation for instance spectra, electromagnetic and weak
transitions, densities, form factors, spectroscopic
amplitudes.
A recent example comes from isotope shift measurements
of drip-line nuclei using collinear laser spectroscopy. Precise
and model independent measurements of charge radii,
magnetic and quadrupole moments provide important
information of the wave functions.
Sudden changes in the charge radii along an isotopic
change are related to changes in the nuclear structure. The
neon isotopes provide a particular interesting example. The
experimental charge radii are compared with microscopic
structure calculations using the Fermionic Molecular
Dynamics (FMD) approach. FMD uses a Gaussian wavepacket basis and allows to describe nuclei with halos and
clustering. The two-proton separation energy in 17Ne is only
0.93 MeV and the structure is understood as an 15O core
and two protons in s2 or d2 configurations. The large charge
radius in 17Ne is caused by a large s2 component of about
40%. In 18Ne the charge radius is smaller due to a smaller s2
component in the wave function. In 19Ne and 20Ne the
charge radii increase again due to clustering in the ground
state wave function.
17Ne
20Ne
22Ne
Densitiy distributions of dominant FMD configurations
indicating an extended two-proton wave function in 17Ne
and α-clustering in 20Ne.
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Onset of complexity
(light nuclei)
 Linking nucleons with nuclei
 Weakly bound and unbound states
 Haloes, clusters and few-body correlations
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Onset of complexity
Integral approach:
The accelerator and separation facilities are parts of the experimental set-up.
The target is a part of the detector system
7H
identification
The system with the highest N/Z ever produced is 7H.
It was identified as a resonance in the
8He(12C,13N)7H reaction at 15 MeV/nucleon.
The active target MAYA was employed to measure
kinematical correlations of the reaction residues.
Higher RIB intensities and next generation instrumentation are
required to study weakly bound states and to explore
the drip-lines towards heavier elements.
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Shell structure and isospin degree of freedom
 Changing shell structure
 Vanishing and new shell gaps in light nuclei
 Proton-neutron symmetric nuclear matter and the proton drip-line
 Limits of existence in proton-rich nuclei and the double magic 100Sn
 Proton-neutron pairing and pairing at high isospin values
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Shell structure and isospin degree of freedom
Collaps of the N = 28 shell closure in 42Si28
ALFA
Château de Crystal
2+  0+ :
770 keV
44S
Secondary beams
 42Si
48Ca
 44S
2+ energy (MeV)
SISSI
4
3
SPEG
Ca
S
Si
2
1
0
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
neutron number N
Wide range of intense RIBs, high-efficiency separators and
gamma-ray arrays needed to probe new shell structures
and isospin degree of freedom
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Superheavy elements
 New elements
 Reaction dynamics
 Spectroscopy
 Masses and atomic structures
 Fission times
 Chemistry
 Towards neutron rich SHE
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Superheavy elements
Taufe von Element 112, am 12. Juli 2010 um 10 Uhr
Copernicium is a noble metal
Hot-fusion cross-sections
High-intensity stable-ion beams, target
developments and high-efficiency detectors
and separators are needed
in the future SHE
research
1 pbarn
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Collective properties
 Collective response of nuclei
 Evolution of nuclear collective properties with spin and temperature
 Shape coexistence, phase transitions and dynamical symmetries
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Collective properties
Return of collective rotation at ultrahigh spin
High-sensitivity gamma-ray spectrometers combined
with various ancillary spectrometers and large variety of
RIB’s and stable-ion beams are vital for extending the studies of
collective response and collective properties to exotic nuclei.
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Reaction dynamics
 Fusion reactions
 Direct and deep-inelastic reactions
 Fission process
 Quasi free scattering
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Reaction dynamics
Quasi-free scattering
The striking observation of a strong
quenching of the single-particle strength
as a function of asymmetry of the neutron
and proton separation energy
Origin unclear ?
Knock-out reactions at high energies with RIB in inverse kinematics
Exotic RIBs up to high energies and innovative spectrometer systems
for kinematically complete measurements are needed
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Ground-state properties
 Charge and matter radii, nuclear moments and spins
 The future with laser spectroscopy methods at ISOL facilities
 The future with spin-oriented radioactive beams at in-flight facilities
 The future with relativistic radioactive beams
 Nuclear masses
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Ground-state properties
Mass measurements
 N = 50 gap survives
Hyperfine-structure and β -NMR measurement
spin and magnetic moment
the ground state of 31Mg
is an 2p-2h deformed intruder state
Very large variety of instruments and
ion-beam manipulation methods needed..
Extreme RIBs are welcome.
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Facilities and instrumentation
 Accelerator facilities
Present European facilities for nuclear structure and reaction studies
FP7 – ENSAR – IA – TNA Facilities
ALTO – Orsay
SIB, (RIB)
GANIL – Caen
RIB, SIB
GSI – Darmstadt RIB, SIB
ISOLDE – CERN RIB
JYFL – Jyväskylä SIB, (RIB)
KVI – Groningen SIB
LNL – Legnaro SIB
LNS – Catania SIB, (RIB)
RIB - Radioactive Ion Beam
SIB - Stable Ion Beam
Facilities and instrumentation
European small scale facilities for nuclear physics and/or applications
including
SPIRIT – FP7 – IA – TNA Facilities
ENSAR – IA – JRA - ENSAR Facilities
Facilities and instrumentation
 Accelerator facilities
RIB roadmap
Timelines for the RIB facilities
Stable ion beams along the NuPECC-ECOS report
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see the Recommendations
Facilities and instrumentation
 Instrumentation

Identification and decay spectroscopy

High-sensitivity gamma-ray and electron detection

High-energy gamma-ray and charged particle calorimetry

Versatile instrumentation for nuclear reactions

Experiments at storage rings

Ground state properties: Traps and lasers

Technological challenges
All large instrumentation projects in today’s nuclear structure and reaction research
are governed by a co-operation in R&D work between groups,
who often represent different subfields of the community
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Facilities and instrumentation
Large number of new state-off-the-art gamma-ray and particle detector arrays ….
CALIFA
HYDE
.. to be combined with other spectrometer systems
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Recommendations
 Radioactive Ion Beam (RIB) Facilities
 The continued strongest support for the full completion and utilization of the
international RIB facilities, NuSTAR@FAIR and SPIRAL2,
in coherence with the ESFRI recommendations.
 The strongest support for the full completion and utilization of HIE-ISOLDE,
recently approved by CERN, and SPES, funded by INFN. These advanced ISOL
facilities, together with SPIRAL2, will bridge the technological gap between
present day facilities and EURISOL.
 The realisation of EURISOL. This long-term goal is the highest priority of our
community for a future major facility that offers unique physics opportunities.
Accession to the ESFRI list, based on the extensive Design Study for EURISOL
carried out during the last decade, should be promoted in the near future.
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Recommendations

Stable-ion beam facilities
 Very strong support for existing and future stable-ion beam facilities.
High-intensity stable-ion beams up to 100 pµA for studies of extremely
weakly produced nuclei such as super-heavy elements. Installation of the
high-intensity LINAG within the SPIRAL2 project and a dedicated cw-linac as
proposed at GSI (NuSTAR-FAIR).
Large variety stable-ion beams up to 100 pnA for in-beam studies,
where the beam intensity is limited by the detector counting rates
(JYFL, LNL and LNS).
Other stable-ion beam facilities are needed for specific experiments,
instrument development and testing, to reach large user communities
and to allow for the education of next-generation researchers (TNA- and
EWIRA- facilities of EU-FP7-IA-ENSAR)
The long-term goal for a new dedicated high-intensity stable ion beam
facility in Europe is recommended as an important future project.
Role of ECOS network will be important.
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Recommendations
 AGATA
Very strong support for the swift realisation of the AGATA spectrometer
AGATA 1/12 demonstrator now in operation at LNL
The completion of the 1/3 of AGATA by 2013 and the realisation of the full
AGATA spectrometer is importance for the successful exploitation of present
and future radioactive and stable-ion beam facilities.
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Recommendations
 Theory Initiative
 Integrating theory into the European nuclear physics infrastructure
The large infrastructures should invest more into theory projects
Funding of project-oriented, medium- and long-term theoretical initiatives
at universities and laboratories.
New permanent coordinating structure for advanced training at
the European level needs to be implemented, either at ECT* or
through new initiatives.
Supporting ECT* Trento in its leading role as a training centre
for young researchers, and an international venue for scientific
meetings that involve both theorists and experimentalists.
Model project:
USA
Universal Nuclear Energy Density Functional
UNEDF
15 institutions
$15M / 5 years
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Thank you for your attention
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