1. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics Nuclear Astrophysics at the Darmstadt superconducting electron linear accelerator S-DALINAC Kerstin Sonnabend ESF Workshop on The future of stable beams in Nuclear Astrophysics Athens, Greece December 14 th to 15 th, 2007 supported by the DFG under grant No. SFB 634

2. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics Contents S-DALINAC at TU Darmstadt Photoactivation experiments –HIPS – High-intensity photon setup –LCS – Laboratory for counting & spectroscopy –NEPTUN – High-resolution photon tagger Electron-scattering experiments –QCLAM – Large-acceptance spectrometer

3. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics S-DALINAC at TU Darmstadt injector: two 20-cell Nb cavities, up to 11 MeV main linac: eight 20-cell Nb cavities, up to 40 MeV per circle first recirculationsecond recirculationbeam extraction – electron energies from 2 to 130 MeV available – cw and pulsed beam operation possible – source for polarized electron beams under construction HIPS

4. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics HIPS – High-intensity photon setup electrons E max  0 ≤ E  ≤ E max  n Au/Re - target n 11 B - target N  ≈ 10 5  / (keV s cm 2 ) ≈ 300 · N  collimator radiator Activation with continuous-energy bremsstrahlung K. Sonnabend et al., Astroph. J. 583 (2003) 506 K. Vogt et al., Nucl. Phys. A707 (2002) 241

5. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics LCS – Laboratory for counting and spectroscopy – three low-energy photon spectrometers (LEPS) – four 30% and 40% HPGe detectors – setups with passive Cu and/or Pb shielding Pb Cu LEPS     Pb HPGe – complementation with x-ray detectors and electron counters Determination of activation yield with  -spectroscopy

6. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics LCS – Laboratory for counting and spectroscopy Sample decay spectra: LEPS versus HPGe

7. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics Photoactivation experiments Activation yield Y measured offline – Use of naturally composed targets (e.g. 196 Hg, 198 Hg, 199m Hg, 200 Hg) – Activate targets simultaneously (e.g. Zr, Re, Ir, and Au) – Measure weak  branchings (e.g. 185 W: T 1/2 = 75 d, E  =125 keV, I  ≈10 -4 )  method perfectly suited for systematic studies Restrictions of activation method – Appropriate lifetime of product nucleus – Appropriate  transitions during decay of product nucleus  Accelerator Mass Spectrometry (AMS) – No direct cross section measurements  Use quasi-monoenergetic photon beams, e.g. AIST, Japan  Use tagged photons, e.g. NEPTUN @ S-DALINAC

8. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics Photoactivation experiments NEPTUN – High-resolution photon tagger tagger system NEPTUN 5 m

9. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics NEPTUN – High-resolution photon tagger Energy range:6 MeV ≤ E  ≤ 20 MeV Energy resolution:  E = 25 keV @ 10 MeV Energy window:≈ 3 MeV Photon intensity:≈ 10 4 keV -1 s -1 1 m Photon energy:E  = E i - E e focal plane radiator magnet coincidence experiment electrons photons

10. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics NEPTUN – High-resolution photon tagger Recent data from test experiment PPSE DE

11. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics NEPTUN – High-resolution photon tagger Recent data from test experiment DESEPP FWHM ≈ 50 keV ≈ 250 keV

12. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics Photoactivation experiments High-resolution cross section measurements detector array NEPTUN 5 m

13. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics NEPTUN – High-resolution photon tagger – 14 liquid scintillator neutron detectors – 8 additional 10 B enriched liquid scintillator detectors – high-resolution cross section measurements – determination of angular momentum of neutrons – ( ,p) and ( ,  ) in preparation Determine ( ,n) cross sections with 100 keV ≤ E n ≤ 10 MeV

14. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics Electron-scattering experiments (e,e‘x) experiments of astrophysical interest QCLAM 5 m

15. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics QCLAM – Large-acceptance spectrometer – scattering chamber – quadrupole magnet – clamshell dipole magnet (deflection angle: 120°) – three multiwire drift chambers – plastic scintillation and plexiglas Cherenkov counters

16. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics – momentum resolution:  p/p = 2  10 -4 – solid angle acceptance: 35 msr – max. central momentum: 200 MeV/c – momentum acceptance: ±10% QCLAM – Large-acceptance spectrometer

17. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics QCLAM – Large-acceptance spectrometer – momentum resolution:  p/p = 2  10 -4 – solid angle acceptance: 6.4 msr – max. central momentum: 95 MeV/c – momentum acceptance: -5% to +8% Electron scattering at 180° deflection angle

18. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics Electron-scattering experiments Recent results on M1 deuteron break-up – high energy resolution and high selectivity of M1 states – precision test of modern theoretical models – prediction of p(n,  )d cross section at Big Bang energies

19. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics Electron-scattering experiments Role of neutrino-induced reactions – properties of pre-collapse core – supernova shock revival – explosive nucleosynthesis – high resolution (e,e‘) data  M1 strength distribution  GT 0 from shell-model calc.  -nucleus cross section Shell-Model total Orbital Spin 52 Cr S-DALINAC excitation energy / MeV K. Langanke et al., PRL 93 (2004) 202501 B(M1) /   N Neutrino Energy / MeV  / 10 -42 cm 2 50 Ti 52 Cr 54 Fe

20. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics – production mechanism of 9 Be and 10,11 B not clear  spallation of 12 C by neutrinos – branching ratios of 12 C(e,e‘x)  detection and discrimination of p, d, t, 3 He and 4 He   E-E-telescopes, TOF and/or PSD – electro-weak theory  extract (, ‘) cross sections Electron-scattering experiments Nucleosynthesis of 9 Be and 10 B

21. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics Experimental hall of the S-DALINAC QCLAM NEPTUNHIPS Setups for experiments on Nuclear Astrophysics

22. Kerstin Sonnabend, IKP, TU Darmstadt S-DALINAC - Nuclear Astrophysics Many thanks to… Technische Universität Darmstadt: M. Fritzsche, E. Gehrmann, J. Glorius, J. Hasper, K. Lindenberg, S. Müller, N. Pietralla, A. Sauerwein, D. Savran, L. Schnorrenberger, and the QCLAM group Universität zu Köln: M. Büssing, J. Endres, M. Elvers, and A. Zilges Roberto Gallino, Torino, Italy Franz Käppeler, Karlsruhe, Germany Karlheinz Langanke, Darmstadt, Germany Alberto Mengoni, Vienna, Austria Thomas Rauscher, Basel, Switzerland