Doubly Magic Nucleus 208 Pb. Indian Institute of Technology Ropar

Transcription

1 Doubly Magic Nucleus 208 Pb Maria Goeppert-Mayer J. Hans D. Jensen

2 Experimental single-particle energies γ-spectrum single-hole energies 208 Pb 207 Pb E lab = 5 MeV/u 3 p 3/2 898 kev 2 f 5/2 570 kev 3 p 1/2 0 kev 207 Pb

3 Experimental single-particle energies single-particle energies 1 i 13/ kev γ-spectrum 208 Pb 209 Bi E lab = 5 MeV/u 2 f 7/2 896 kev 1 h 9/2 209 Bi kev

4 Experimental single-particle energies particle states 209 Bi 1 i 13/ kev 2 f 7/2 896 kev 1 h 9/2 0 kev 209 Pb 207 Tl 208 Pb energy of shell closure: BE Pb) BE( Pb) = E(2 g ( 9/ BE( Pb) BE( Pb) = E(3 p1/ 2) E ( 2 g ) 9/ 2 E(3 p 1/ 2 ) = BE( = Pb 209 ) Pb) + BE( 207 Pb) 2 BE( 208 Pb) protons hole states neutrons BE Bi) BE( Pb) = E(1 h ( 9/ BE( Tl) BE( Pb) = E(3s1/ 2) E ( 1h ) 9/ 2 E(3s 1/ 2 ) = BE( 209 ) Bi) + BE( = 4.211MeV 207 Tl) 2 BE( 208 Pb)

5 Octupole Vibrational States in the Lead Region ħωω 3 206,207,209 Pb

6 Octupole Vibrational States in the Lead Region ħωω 3

7 The Darmstadt-Heidelberg Crystal Ball extended by EUROBALL-3 Ge-detectors

8 The Darmstadt-Heidelberg Crystal Ball extended by EUROBALL-3 Ge-detectors θθ γγ = RR = 36 cccc Crystal Ball: Ω CB = 83% P photopeak 53% Cluster ring: Ω EB = 7% P photopeak 2.2% March 27 September 6, 1996

9 Octupole Vibrational States in the Lead Region 206 Pb 24% 207 Pb 22% 208 Pb 52% excitation probability for the 1-excited state E2 excitation E3 excitation

10 Coulomb Excitation for 208 Pb on 206 Pb B(E3) 34 spu 20 spu Nucl Data: 36 spu

11 Coulomb Excitation for 238 U on 206 Pb B(E3) 36 spu 20 spu J. Baumann for EPOS

12 Superposition of Vibrational and Particle Motion 3 h 9 2 septuplet 209 Bi h 9 2 weak coupling: Σ:

13 Superposition of Vibrational and Particle Motion νν pp 1 2, 2 νν pp 1 2, 1 particle-hole states 2 - phonon ππ h 9 2, phonon octupole vibration

14 Coulomb Excitation for 208 Pb on 208 Pb 206,207,209 Pb 209 Pb!

15 Coulomb Excitation for 208 Pb on 208 Pb at 5.0 MeV/u BB EEE; BB EEE; = vibrational

16 Octupole Vibrational States in 206 Pb, 207 Pb, 208 Pb and 209 Bi vibrational excitation ħωω 3 is very similar B(E3) values are well described in weak coupling model collective strength depends on particle configuration 2 phonon octupole vibrational states not observed at 5 MeV/u (insufficient Compton suppression of EUROBALL detectors) 6 + particle-hole state contains 18% of the collective vibrational strength transfer reactions ( 209 Pb) observed at 5 MeV/u H.J. Wollersheim, E. Lubkiewicz, A. Gadea, J. Gerl, M. Kaspar, I. Kojouharov, Th. Kröll, R. Kulessa, I. Peter, M. Rejmund, J.A. Ros, H. Schaffner, Ch. Schlegel, K. Vetter GSI-Darmstadt, Jagellonian University Cracow, I.F.I.C.-Valencia

17 Octupole Vibrational States in the Lead Region 208 Pb Pb; E/A 1 = 5 MeV/u σσ 6 + = mmmm σσ 4 + = mmmm σσ 2 + = mmmm σσ 0 + = mmmm 1-phonon 2-phonon

18 Experimental Setup for 208 Pb on 208 Pb at 6.2 MeV/u

19 Coulomb Excitation for 208 Pb on 208 Pb at 6.2 MeV/u 207,209 Pb

20 Coulomb Excitation for 208 Pb on 208 Pb at 6.2 MeV/u

21 Coulomb Excitation for 208 Pb on 208 Pb at 6.2 MeV/u

22 Coulomb and Nuclear Excitation for 208 Pb on 206 Pb at 6.2 MeV/u particle-γ angular correlation electromagnetic excitation nuclear excitation g(2 + ) = 0 unperturbed p-γ angular correlation σσ nnnnnnnn σσ tttttttttt = 63% analysis with Ptolemy code

23 Coulomb and Nuclear Excitation for 208 Pb on 208 Pb at 6.2 MeV/u analysis with Ptolemy code

24 Coulomb and Nuclear Excitation for 208 Pb on 208 Pb at 6.2 MeV/u analysis with Ptolemy code

25 Energy Splitting of the 2-Phonon States