Nuclear Resonance Fluorescence using an FEL generated γ-beam
Abstract
The HIGS facility has been used to perform a nuclear resonance fluorescence (NRF) experiment on the semi-magic nucleus ^138Ba. Four HPGe detectors were used to measure the analyzing power of 18 previously identified dipole resonances in ^138Ba with excitation energies between 5.5 MeV and 6.5 MeV. The nearly monoenergetic (Δ E ≈ 2%), completely linearly polarized, high intensity (N_γ > 10^6 sec-1 at target position) HIGS γ-beam enabled us to make unambiguous parity assignments to these resonances in just hours of beam on target. All of these dipole excitations were found to have an electric character (J^π = 1^-) including the J=1 level at 5.644 MeV, which was previously tentatively assigned 1^(+) from Compton polarimetry in NRF using unpolarized bremsstrahlung (R.-D. Herzberg et al.), Phys. Rev. C 60, 051307 (1999).
- Publication:
-
APS Meeting Abstracts
- Pub Date:
- October 2001
- Bibcode:
- 2001APS..HAW.DD006P