Download presentation

Presentation is loading. Please wait.

Published byRoxana Flatter Modified over 2 years ago

1
Presentation of the PhD thesis “Statistical properties in the quasi- continuum of atomic nuclei” Ann-Cecilie Larsen May 20, 2008 Ann-Cecilie Larsen May 20, 2008

2
Ann-Cecilie Larsen2 The atomic nucleus

3
May 20, 2008Ann-Cecilie Larsen3 Quantum energy levels Nuclear level density = number of energy levels within one energy unit

4
May 20, 2008Ann-Cecilie Larsen4 Decay probability Transition between quantum levels Fermi’s golden rule: Gamma-ray transmission coefficients and strength functions Transition between quantum levels Fermi’s golden rule: Gamma-ray transmission coefficients and strength functions Giant dipole resonance, 98 Mo i f

5
May 20, 2008Ann-Cecilie Larsen5 Applications Nucleosynthesis in supernovae Transmutation of nuclear waste Nucleosynthesis in supernovae Transmutation of nuclear waste

6
May 20, 2008Ann-Cecilie Larsen6 Motivation Level density and gamma-ray strength function in medium-mass nuclei: 44,45 Sc, 50,51 V, 93-98 Mo Shell effects? Decay probability in the quasi-continuum? Level density and gamma-ray strength function in medium-mass nuclei: 44,45 Sc, 50,51 V, 93-98 Mo Shell effects? Decay probability in the quasi-continuum?

7
May 20, 2008Ann-Cecilie Larsen7 The Oslo Cyclotron Laboratory Reactions: inelastic scattering ( 3 He, 3 He’ ), and pick-up ( 3 He, ) Low spin and high intrinsic excitation energy CACTUS: 28 5”x5” NaI (~15% eff.) Eight E-E Si particle telescopes Reactions: inelastic scattering ( 3 He, 3 He’ ), and pick-up ( 3 He, ) Low spin and high intrinsic excitation energy CACTUS: 28 5”x5” NaI (~15% eff.) Eight E-E Si particle telescopes

8
May 20, 2008Ann-Cecilie Larsen8 Particle-gamma coincidences Si E-E telescope 45 o NaI(Tl) 3 He Target nucleus

9
May 20, 2008Ann-Cecilie Larsen9 The Oslo method in a Unfold -ray spectra Apply first-generation subtraction method Ansatz: decay probability (E x -E ) T (E ) Unfold -ray spectra Apply first-generation subtraction method Ansatz: decay probability (E x -E ) T (E ) 44 Sc

10
May 20, 2008Ann-Cecilie Larsen10 Quality of the extraction, 44 Sc

11
May 20, 2008Ann-Cecilie Larsen11 Experimental level densities

12
May 20, 2008Ann-Cecilie Larsen12 Shell effects in the Mo isotopes Back-shifted Fermi gas : Calc. from neutron res. data

13
May 20, 2008Ann-Cecilie Larsen13 Comparison with theory, 51 V Fermi gas?

14
May 20, 2008Ann-Cecilie Larsen14 Thermodynamics Microcanonical vs. canonical ensemble

15
May 20, 2008Ann-Cecilie Larsen15 Microcanonical entropy

16
May 20, 2008Ann-Cecilie Larsen16 Combinatorial model Combining all possible proton and neutron configurations Nilsson energy scheme BCS quasiparticles Combining all possible proton and neutron configurations Nilsson energy scheme BCS quasiparticles J

17
May 20, 2008Ann-Cecilie Larsen17 Calculated level densities, average number of broken pairs

18
May 20, 2008Ann-Cecilie Larsen18 Parity asymmetry Defining the parity asymmetry:

19
May 20, 2008Ann-Cecilie Larsen19 Experimental gamma-ray strength functions

20
May 20, 2008Ann-Cecilie Larsen20 Comparison with theory Anomalous strength functions? T XL (E ) = 2 E 2L+1 f XL f XL (E ) = E -(2L+1) XL (E ) /D Assuming only dipole radiation: f (E ) T (E ) / 2 E 3

21
May 20, 2008Ann-Cecilie Larsen21 Papers included in the thesis PublicationMy contribution Radiative strength functions in 93-98 Mo [Phys. Rev. C 71, 044307 (2005)] Discussions of the results, suggestions to and proof-reading of the manuscript. Level densities and thermodynamic quantities of heated 93-98 Mo isotopes [Phys. Rev. C 73, 034311 (2006)] Discussions of the results (mainly level densities and microcanonical results), suggestions to and proof-reading of the manuscript. Microcanonical entropies and radiative strength functions of 50,51 V [Phys. Rev. C 73, 064301 (2006)] Main author. Performed the data analysis and calculations. Wrote the manuscript. Nuclear level densities and gamma-ray strength functions in 44,45 Sc [Phys. Rev. C 76, 044303 (2007)] Main author. Performed the data analysis and calculations. Wrote the manuscript. Level densities of 44 Sc and 47 Ti from different experimental techniques [Phys. Rev. C 77, 034613 (2008)] Provided data and info for the OCL exp. ( 44 Sc). Suggestions to and proof-reading of the manuscript. Participated in the Ohio exp.

22
May 20, 2008Ann-Cecilie Larsen22 Highlights The Oslo method works well for medium- mass nuclei Pronounced shell effects Single quasi-particle entropy constant, but vanish near shell closures Enhancement of low-energy gamma decay probability established for all nuclei studied The Oslo method works well for medium- mass nuclei Pronounced shell effects Single quasi-particle entropy constant, but vanish near shell closures Enhancement of low-energy gamma decay probability established for all nuclei studied

Similar presentations

OK

Structure of the ECEC candidate daughter 112 Cd P.E. Garrett University of Guelph TRIUMF Excellence Cluster “Universe”, Technische Universität München.

Structure of the ECEC candidate daughter 112 Cd P.E. Garrett University of Guelph TRIUMF Excellence Cluster “Universe”, Technische Universität München.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Led based moving message display ppt online Ppt on low level language pdf Ppt on water scarcity in china Ppt on object-oriented programming tutorial Ppt on credit policy pdf Ppt on standing order Ppt on object-oriented programming polymorphism Ppt on product advertising examples Ppt on motivation Ppt on chief minister of india