1. The 3 MeV pygmy resonance in 163,164 Dy Hilde-Therese Nyhus Department of Physics University of Oslo

2.  Introduction  Motivation for analyzing these nuclei  Experimental method  Level density  Gamma-ray strength function  Introduction  Motivation for analyzing these nuclei  Experimental method  Level density  Gamma-ray strength function

3. Motivation

4. Various other rare earth nuclei have been studied using the Oslo method, one has then measured a width of the pygmy resonance between 1.2-1.5 MeV. This contradicts what has been measured in Prague for other rare earth nuclei, where about half the width has been found.

5. The reactions used to produce the nuclei

6.  At Oslo Cyclotron Laboratory: 164 Dy( 3 He, 3 He*) 164 Dy 164 Dy( 3 He,  ) 163 Dy

7. The reactions used to produce the nuclei  At Oslo Cyclotron Laboratory: 164 Dy( 3 He, 3 He*) 164 Dy 164 Dy( 3 He,  ) 163 Dy In Prague: 162 Dy(n,  ) 163 Dy

8. Experimental method -Gate on the various particles to construct coincidence matrix.

9. Coincidence matrixes 163 Dy 164 Dy

10. Experimental method -Gate on the various particles to construct coincidence matrix. -Unfold the gamma spectrum and generate first generation matrix.

11. First generation matrixes 163 Dy 164 Dy

12. Experimental method -Gate on the various particles to construct coincidence matrix. -Unfold the gamma spectrum and generate first generation matrix. -The experimentally obtained first generation matrix is according to the Brink-Axel hypothesis proportional to the level density and gamma ray strength function.

13. Level density in 163,164 Dy Preliminary 163 Dy 164 Dy

14. Gamma-ray strength function with pygmy resonance  Gamma-ray strength function in 164 Dy, with a pygmy resonance. Gamma-ray strength function in 163 Dy, with a pygmy resonance. The width of the pygmy resconance masured in Prague is 0.6 MeV 163 Dy 164 Dy Preliminary

15. Gamma-ray strength function with pygmy resonance Gamma-ray strength function in 163 Dy, with a pygmy resonance. The width of the pygmy resconance masured in Prague is 0.6 MeV 163 Dy Preliminary