1. Photodissociation as a tool for nuclear astrophysics S. Müller, M. Elvers, J. Endres, M. Fritzsche, J. Hasper, K. Lindenberg, L. Kern, D. Savran, C. Siegel, K. Sonnabend, S. Volz, and A. Zilges Institut für Kernphysik TU Darmstadt

2. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics Outline Photoactivation with bremsstrahlung –s-process branching points –( ,n)-reaction rates for the p-process Coulomb breakup in inverse kinematics –A first test: Mo isotopes Summary and outlook

3. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics The photoactivation setup at the S-DALINAC HPGe radiator target e-e-  Energy Intensity B-target-B Au/Re-target-Au/Re Photon flux: 10 8  /(keV s cm 2 )   n (E) E max Online calibration via 11 B( ,  ’)

4. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics Offline  -spectroscopy of the activated targets Yield Low energy photon setup 100 Mo( ,n) 99 Mo(  - ) 99 Tc E [keV] counts Input: parameterization 1) statistical model 2) empirical E max =9 MeV

5. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics Branching points in the s-process

6. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics Branching points in the s-process E [MeV]  [mb] T. Shizuma et al., Phys. Rev. C 72, 025808 (2005) S. Müller et al., Phys. Rev. C 73, 025804 (2006) 187 Re( ,n) 186 Re (n,  )-cross sections via the inverse ( ,n)-reaction Goryachev Shizuma Müller NONSMOKER MOST MOST: = 616 mb NON-SMOKER: = 1550 mb 186 Re(n,  ):

7. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics Photoactivation May 2006 152 Gd( ,n), 154 Gd( ,n), 160 Gd( ,n) 152 Sm( ,n), 154 Sm( ,n) 148 Nd( ,n), 150 Nd( ,n) Analysis via AMS

8. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics The Gamow window for ( ,n)-reactions in p-process Reaction rate: P. Mohr et al., Phys. Lett. B 488 (2000) 127 E [keV] Temperature:T 9 =2.5  ( ,n), ( ,p), (  )

9. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics Motivation M. Arnould & S. Goriely, Phys. Rep. 384 (2003) 1

10. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics ( ,n)-reaction rates in the A>180 region 1 Vogt et al., Phys. Rev. C 63 (2001), 055802 Vogt et al., Nucl. Phys. A 707 (2002), 241 Sonnabend et al., Phys. Rev. C 70, (2004), 035802 Hasper et al., to be published

11. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics Motivation M. Arnould & S. Goriely, Phys. Rep. 384 (2003) 1

12. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics Coulomb break up in inverse kinematics at GSI/LAND ~18m TOF, x,y Tracking through ALADIN Projectile tracking Excitation energy E * from a kinematical complete measurement of all outgoing particles. 92,93,94,100 Mo( ,n) TOF,  E

13. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics Summary and outlook Summary s-Process branching points are accessible via the inverse ( ,n)-reaction ( ,n)-cross sections for neutron deficient nuclei are measured over a wide mass range  test for statistical model calculations Outlook Coulomb breakup will be an ideal tool to measure ( ,n)-cross section for proton rich exotic nuclei The photon Tagger NEPTUN will measure directly ( ,n)-cross section for stable nuclei with high resolution

14. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics Supported by DFG (SFB 634) and BMBF (06DA115) Contact: www.zilges.de and www.sfb634.dewww.zilges.dewww.sfb634.de Collaboration S295 T. Aumann, M. Babilon, H. Emling, M. Erhard, W. Grosse, M. Heil, A. Junghans, F. Käppeler, S. Müller, N. Nankov, R. Plag, U. Datta Pramanik, H. Simon, K. Sümmerer, A. Wagner, A. Zilges I would like to thank… T. Rauscher, S. Goriely

15. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics

16. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics NEPTUN: A high resolution tagger Coincidence DAQ Magnet Bremsstrahlung Target & detectors Focal plane and electron detectors Thin radiator target E0E0 EeEe EE e-e- Parameters e - -energy: 28 - 34 MeV  -energy: 8 – 20 MeV Intensity: 10 4 s -1 keV -1 Resolution: 0.25% CATCH module developed for COMPASS

17. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics NEPTUN: A high resolution tagger Parameters e - -energy: 28 - 34 MeV  -energy: 8 – 20 MeV Intensity: 10 4 s -1 keV -1 Resolution: 0.25% First test October 2006

18. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics Photoactivation May 2006 152 Gd( ,n), 154 Gd( ,n), 160 Gd( ,n) 152 Sm( ,n), 154 Sm( ,n) 148 Nd( ,n), 150 Nd( ,n) E [keV] counts nat Gd, E 0 =9.35 MeV nat Sm, E 0 =9.35 MeV nat Nd, E 0 =8.6 MeV

19. Sebastian Müller TU DarmstadtPhotodissociation as a tool for nuclear astrophysics