1. N. Pietralla and K. Sonnabend for the SFB 634
Nuclear Structure Physics at the Darmstadt superconducting electron linear accelerator S-DALINAC
N. Pietralla and K. Sonnabend for the SFB 634
Workshop on European Small-Scale Accelerator Facilities
Aghios Nikolaos, Crete, Greece
September 7th to 8th, 2007
supported by the DFG under grant No. SFB 634

2. Accelerator hall of the S-DALINAC
HIPS
– electron energies from 2 to 130 MeV available
– cw and pulsed beam operation possible
– source for polarized electron beams under construction

3. HIPS – High-intensity photon setup
– continuous-energy bremsstrahlung
– 2 MeV ≤ Emax ≤ 11 MeV
– photon intensities: keV-1s-1cm-2
– two target positions for simultanuous (g,g‘) experiments
– up to four HPGe detectors  partly passively shielded  partly segmented

4. HIPS – High-intensity photon setup1-
11B

5. Experimental hall of the S-DALINAC
NEPTUN – High-resolution tagger
tagger system

6. NEPTUN – High-resolution tagger
focal plane
radiator
magnet
coincidence
experiment
1 m
Energy range: 6 MeV ≤ Eg ≤ 20 MeV
Energy resolution: DE = MeV
Energy window: ≈ 3 MeV
Photon intensity: ≈ 104 keV-1s-1
Photon energy: Eg = Ei - Ee

7. NEPTUN – High-resolution tagger
– simulation of detector response
– untagged photon spectrum
– tagged photon spectrum: Eg = 10 MeV

8. Experimental hall of the S-DALINAC
LINTOTT – High-resolution spectrometer
LINTOTT

9. LINTOTT – High-resolution spectrometer
electrons
energy range: 18 MeV ≤ Ee ≤ 120 MeV
detector system
detector system: 96 silicon strip detectors
scattered electrons
deflection angle: 169.6º ± 0.1º
scattering chamber
energy resolution: DE/E ≈ 1  10-4
data rate: up to 100 kHz

10. LINTOTT – High-resolution spectrometer
94Mo(e,e’)
excitation energy / MeV 1 2 3 4
counts / mC
0.0
0.1
0.2
– very good energy resolution (see ground-state)
– far-off yrast spectroscopy possible (up to observed)
– ideal method to study one-phonon modes
 symmetric quadrupole phonon
 symmetric octupole phonon
 mixed-symmetry state
O.Burda et al., PRL 99 (2007)

11. LINTOTT – High-resolution spectrometer
Planned experimental program
Determination of excitation strengths and form factors of low-spin excitations
– mixed-symmetry states in mass regions A = 90 and 130
– intrinsic structures in shape-phase transitional nuclei
– investigation of new electric dipole modes (besides IVGDR)
form factors of PDR states in N = 82 isotones and 208Pb
find evidence for purely transverse E1 mode below GDR

12. Experimental hall of the S-DALINAC
QCLAM – Large acceptance spectrometer
QCLAM

13. QCLAM – Large-acceptance spectrometer
Planned experimental program
– (e,e‘x) coincidence experiments for the investigation of new electric dipole modes (besides IVGDR)
form factors of PDR states in N = 82 isotones and 208Pb
find evidence for purely transverse E1 mode below GDR
– excitation and decay of ISGDR in 58Ni, 90Zr, 140Ce, and 208Pb
– experiments on a-cluster states in light N = Z nuclei
– (e,e‘g) coincidence measurements using Ge detectors

14. Experimental hall of the S-DALINAC
NEPTUN
HIPS
QCLAM
LINTOTT

15. Photon scattering - Nuclear Resonance Fluorescence
U. Kneissl, N. Pietralla, A. Zilges, J. Phys. G 32 (2006) R217
HPGe
target
energy
intensity
electrons
radiator target
energy
intensity
bremsstrahlung