Early History: The Beginnings

• 1900: Discovery of gamma rays by Villard• 1910: Bragg shows that gammas are rays• 1914: Rutherford and Andrade measure wavelengths (crystal diffraction).

Rutherford coins the name ‘gamma rays’ • 1924: Pauli suggests that hyperfine splitting is related to deformed nuclei• 1935: Schüler and Schmidt measure nuclear quadrupole moment (Casimir 1936)• 1936: Bohr’s paper on the deformed nuclear liquid drop. Vibrations.• 1937: Bohr and Kalckar. Rotations and the moment of inertia• 1938: Teller and Wheeler. Rotations.• 1939: Fission and shape degrees of freedom (Meitner & Frisch, Bohr & Wheeler)

o For theory highlights, see excellent review by Satula and Wyss: Rep. Prog. Phys. 68, 131 (2005)

o Technological milestones not included

Historical Perspective

• 1948: Nuclear shell model (Jensen and Goeppert-Mayer)• 1950: Deformed shell model (Rainwater)• 1951: Particle+rotor model; intrinsic system (A. Bohr)• 1952: Nuclear Jahn-Teller effect (particle-vibration coupling) Rotational states in the actinides• 1953: Unified model (Bohr & Mottelson, Hill & Wheeler)

Coulomb excitation• 1954: Cranking model• 1955: Nilsson model (Nilsson and Moszkowski)

Intensity (Alaga) rules • 1958: Shell-model description of nuclear rotation: Elliott’s SU(3) model. Band

termination Nuclear superconductivity (Bohr-Mottelson-Pines, Belyaev) • 1960: Coriolis anti-pairing• 1961: Systematic calculations of moments of inertia (with pairing)• 1962: Discovery of fission isomers• 1963: Observation of 10+ state with alpha beam• 1964: Shell energy• 1965: Observation of 20+ state with heavy-ion beam • 1967: Theory of shell correction; prediction of superdeformation

Age of Discovery

• 1969: “Nuclear Structure vol. I” by B&M Superheavy magic numbers• 1970: First cranked HFB calculations• 1971: Backbending observed • 1972: Rotational alignment• 1974: Rotating liquid drop model Interacting Boson Model introduced

Yrast traps (high-K isomers) found• 1975: Signature quantum number “Nuclear Structure vol. II” by B&M • 1976: Rotating shell correction approach. Prediction of high-spin superdeformation• 1979: Cranked Shell Model. Angular momentum alignment. Quasiparticle diagrams• 1981: Prediction of uniform rotation around non-principal axis• 1983: Terminating bands predicted in heavy nuclei (observed 1984) Discovery of a nuclear reflection-asymmetric rotor• 1984: Theory of reflection-asymmetric nuclear rotors

Discovery of the scissors mode• 1985: Rotational quasi-continuum studied• 1986: Discovery of high-spin superdeformation Rotational damping predicted • 1988: Deep inelastic spectroscopy introduced• 1990: Discovery of identical bands• 1991: Discovery of magnetic rotation First g.s. g-factor measurement in light neutron-rich nuclei using fast beams• 1993: Shears mechanism and explanation of magnetic rotation. Realization that deformations can be associated with currents.

1995: Gammasphere construction completed

•Fundamentals of shell model tested

•Basic collective modes characterized

•Unified model extremely successful

•Simple geometric and algebraic schemes introduced

•Useful labels to characterize states and phenomena

•Powerful phenomenology developed

•Can interpret basic features of nuclear response to high spin

•Tools of trade mastered

•Data systematized

but…

Only qualitative understanding (e.g., MOI)

Lacking microscopic understanding rooted in

interaction

…Labeling is not equivalent to understanding…

•Fundamentals of shell model tested

•Basic collective modes characterized

•Unified model extremely successful

•Simple geometric and algebraic schemes introduced

•Useful labels to characterize states and phenomena

•Powerful phenomenology developed

•Can interpret basic features of nuclear response to high spin

•Tools of trade mastered

•Data systematized

but…

Only qualitative understanding (e.g., MOI)

Lacking microscopic understanding rooted in

interaction

…Labeling is not equivalent to understanding…

Vocabulary, Learning the Rules of the Game

• 1969: “Nuclear Structure vol. I” by B&M Superheavy magic numbers• 1970: First cranked HFB calculations• 1971: Backbending observed • 1972: Rotational alignment• 1974: Rotating liquid drop model Interacting Boson Model introduced

Yrast traps (high-K isomers) found• 1975: Signature quantum number “Nuclear Structure vol. II” by B&M • 1976: Rotating shell correction approach. Prediction of high-spin superdeformation• 1979: Cranked Shell Model. Angular momentum alignment. Quasiparticle diagrams• 1981: Prediction of uniform rotation around non-principal axis• 1983: Terminating bands predicted in heavy nuclei (observed 1984) Discovery of a nuclear reflection-asymmetric rotor• 1984: Theory of reflection-asymmetric nuclear rotors

Discovery of the scissors mode• 1985: Rotational quasi-continuum studied• 1986: Discovery of high-spin superdeformation Rotational damping predicted • 1988: Deep inelastic spectroscopy introduced• 1990: Discovery of identical bands• 1991: Discovery of magnetic rotation First g.s. g-factor measurement in light neutron-rich nuclei using fast beams• 1993: Shears mechanism and explanation of magnetic rotation. Realization that deformations can be associated with currents.

1995: Gammasphere construction completed

How are complex systems built from a few, simple ingredients?

- Shell Structure

- Pairing

- Collective modes

What leads to simple excitations and regularities in complex systems?

-Dynamical Symmetries

-Critical Point Symmetries

The Limits of nuclear existence?

-Drip-lines

-Superheavy elements

How are complex systems built from a few, simple ingredients?

- Shell Structure

- Pairing

- Collective modes

What leads to simple excitations and regularities in complex systems?

-Dynamical Symmetries

-Critical Point Symmetries

The Limits of nuclear existence?

-Drip-lines

-Superheavy elements

Vocabulary, learning the rules of the game

• 1995: Relativistic Coulex of light neutron-rich nuclei• 1996: Extreme s.p. SM picture of high-spin superdeformations• 1998: Prompt proton decay of a well-deformed rotational band• 1999: High-spin states of the heaviest elements• 2001: Rotating proton emitters• 2002: Superdeformed wobblers

Deep-inelastic studies of neutron-rich nuclei (-decays with prompt gammas) Coulex with heavy neutron-rich ISOL beams

Important SD-yrast link in 152Dy found First g-factor measurement on isomers in heavy neutron-rich nuclei with fast beams

• 2003: Shell structure with two-proton knockout (gammas with knockout residues)• 2005: First nuclear moment measurement with radioactive beams by the recoil-in- vacuum technique Pygmy and GDR around 132Sn

Multiple Coulex with heavy proton-rich ISOL beams Transfer in inverse kinematics with ISOL beams using -particle

coincidences and particle- angular correlations• 2006: Discrete states in 58Ni at E=42 MeV, E~4.4 MeV

•Gamma ray spectroscopy used as a powerful tool

•Life at the limits is demanding: many triggers required

•Coupling of angular momentum with isospin extremely

successful

•Addressing basic questions of the nuclear many-body problem

•Probing unique features of the polarized system

•Contributions across disciplines

•Applications?

From Quantity to Quality

•Gamma ray spectroscopy used as a powerful tool

•Life at the limits is demanding: many triggers required

•Coupling of angular momentum with isospin extremely

successful

•Addressing basic questions of the nuclear many-body problem

•Probing unique features of the polarized system

•Contributions across disciplines

•Applications?

From Quantity to Quality

Modern Era