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European SSAF Crete, Sept. 7-8, 2007 European SSAF Crete, Sept. 7-8, 2007 1 1 Oslo Cyclotron Laboratory and the Nuclear Physics Program S. Siem Department.

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Presentation on theme: "European SSAF Crete, Sept. 7-8, 2007 European SSAF Crete, Sept. 7-8, 2007 1 1 Oslo Cyclotron Laboratory and the Nuclear Physics Program S. Siem Department."— Presentation transcript:

1 European SSAF Crete, Sept. 7-8, 2007 European SSAF Crete, Sept. 7-8, Oslo Cyclotron Laboratory and the Nuclear Physics Program S. Siem Department of Physics University of Oslo S. Siem Department of Physics University of Oslo

2 European SSAF Crete, Sept. 7-8, Oslo Cyclotron Laboratory (OCL) Protons 2-35 MeV Deuterons4-18 MeV 3He6-47 MeV 4He8-35 MeV Protons 2-35 MeV Deuterons4-18 MeV 3He6-47 MeV 4He8-35 MeV

3 European SSAF Crete, Sept. 7-8, Experimental set-up CACTUS: 28 NaI 5x5 and 8 Si telescopes CACTUS: 28 NaI 5x5 and 8 Si telescopes

4 European SSAF Crete, Sept. 7-8, The Physics Nuclear structure and decay properties in continuum Spin ħ ExEx T = 1 MeV Yrast line (no levels)

5 European SSAF Crete, Sept. 7-8, The energy distribution of primary rays contains information on the level density ρ(Ef) and gamma-ray transmission coefficient T(E ) The Brink Axel hypothesis:

6 European SSAF Crete, Sept. 7-8, Level density Gamma-ray strength functions 148 Sm

7 European SSAF Crete, Sept. 7-8, Sm 146 Sm Level Densities Left: Comparing even-even nuclei: the nuclei closer to a closed shell and have smaller level density, but more structure. Right: There is a big difference between odd and even nuclei due to pairing Left: Comparing even-even nuclei: the nuclei closer to a closed shell and have smaller level density, but more structure. Right: There is a big difference between odd and even nuclei due to pairing

8 European SSAF Crete, Sept. 7-8, Microcanonical Temperature

9 European SSAF Crete, Sept. 7-8, Radiative strength functions for some rare earth nuclei. Roughly, the shape corresponds to the tail of the giant electric dipole resonance (GEDR). There is a significant bump superimposed on the radiative strength function, which is interpreted as scissors mode in continuum (M1). Radiative strength functions for some rare earth nuclei. Roughly, the shape corresponds to the tail of the giant electric dipole resonance (GEDR). There is a significant bump superimposed on the radiative strength function, which is interpreted as scissors mode in continuum (M1).

10 European SSAF Crete, Sept. 7-8, Scissors mode

11 European SSAF Crete, Sept. 7-8, A.Voinov et al. Phys.Rev.Lett.93, (2004) Radiative strength function of 57Fe A large unexpected increase in the radiative strength function was first seen in iron. We still dont have an explanation for what the physics behind it is.

12 European SSAF Crete, Sept. 7-8, Features and future plans OCL is modern and well equipped Continues beam time of 1-2 weeks New Silicon Ring (SiRi) with 64 particle telescopes Plans to replace the 28 NaI detectors with BrilLanCe 380 crystals OCL is modern and well equipped Continues beam time of 1-2 weeks New Silicon Ring (SiRi) with 64 particle telescopes Plans to replace the 28 NaI detectors with BrilLanCe 380 crystals

13 European SSAF Crete, Sept. 7-8, In Oslo we now have: 2 PhD positions and 1 Postdoc position To be filled as soon as possible.


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