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Challenges on phase transitions and gamma-strength functions Magne Guttormsen Department of Physics, University of Oslo. Oslo method Thermodynamics Electromagnetic transitions Challenges. Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007. E x.

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Challenges on phase transitions and gamma-strength functions Magne Guttormsen

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  • Challenges on phase transitions and

  • gamma-strength functions

  • Magne Guttormsen

  • Department of Physics, University of Oslo

    • Oslo method

    • Thermodynamics

    • Electromagnetic transitions

    • Challenges

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Ex

    T = 1 MeV

    Spin

    2-6 ħ

    Spin-energy diagram

    Yrast line

    (no levels)

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    M

    F0

    -

    G

    M-1

    =

    1

    W

    The first generation method

    F0

    F1

    F2

    F3

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Gamma-ray multiplicity

    E

    Spin

    E

    Spin

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    The Brink Axel hypothesis

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Does it work?

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Nuclear entropy

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    canonical - canonical ensemble

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Rare-earth region, case erbium

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Preliminary

    Proton number Z = 50

    Neutron Cooper pairs

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    J.Lee and J.M.Kosterlitz,

    Phys. Rev. Lett. 65, 137 (1990)

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Heat

    bath

    Isolated

    E

    T

    T

    Boltzmannfactor

    S = S0 + S* + S1

    Challenges, new thermodynamic

    Negative Cv(E) and T(E) Smoothed (up to E = 100 MeV)

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Loved child, many names

    • Radiative strength function (RSF)

    • Photon strength function (PSF)

    • Gamma-ray strength function

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Ex

    8

    5

    2

    E

    First generation

    procedure

    Axel-Brink

    factorization

    into  and f

    2 4 6 8

    2 4 6 8

    Simulation tests of the Oslo method

    Event-by-event data

    generated in Prague

    with DICEBOX

    Sorted in Oslo into

    (Ex, E) matrix

    Ex

    8

    5

    2

    E

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Results from the blind test

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Radiative strength functions

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Pygmy resonance

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Scissors mode

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Giant dipole resonance

    Kadmenskii, Markushev

    and Furman (KMF) model

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Unexpected RSF upbend

    Physics News Update

    Voinov et al., Physical Review Letters,1 October 2004.

    Also observed in: Mo, V, Sc, Ni, Ti

    (3He, 3He) and (3He, 4He) reactions

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Upbend in iron

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Temperature dependence?

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


    Verifications

    Budapest

    Research Reactor

    (n, ) reaction

    INPP, Ohio University

    (d,n) reaction

    Subatomic and Astrophysics Division Annual Meeting 2007


    Challenges

    • Understand the difference in quantities observed in different experiments

      • Pygmy resonance

      • GEDR-tail match

      • Low energy -strength

    • Spin distribution

    • Parity asymmetry

    • Thermalization

    • -canonical or canonical ensemble - or another theory?

    • Critical T, how to interpret and measure?

    • Single quasi-particle entropy

    Workshop on
Level Density and
Gamma Strength in Continuum, Oslo, May 21 - 24, 2007


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