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HK: Physik der Hadronen und Kerne
HK 15: Plenary Session
HK 15.4: Plenarvortrag
Dienstag, 12. März 2002, 15:45–16:15, Plenarsaal
Nuclear Physics with a Free Electron LASER$ — •N. Pietralla — Institut für Kernphysik, Universität zu Köln — WNSL, Yale University, U.S.A.
The electron storage ring at the Duke Free Electron LASER Laboratory
operates at electron energies between 0.2 and 1.1 GeV.
Its beam drives the OK-4 Free Electron LASER with tunable wavelengths
in the optical range.
The high photon density inside of the optical cavity enables one to
obtain a large luminosity for Compton scattering processes
between the polarized optical LASER photons and the relativistic
electrons in the ring.
Compton scattered photons experience a forward-peaked Lorentz-boost
by a factor of 106–108 by transformation to the
lab system and they form after collimation a nearly monochromatic,
tunable, completely polarized γ-ray beam with an intensity of
up to 109 γ’s/sec.
This “High Intensity γ-ray Source” (HIγS),
with a degree of linear polarization of Pγ> 99%
and a narrow band width of Δ Eγ/Eγ< 4%,
offers new conditions for experiments with
photo-nuclear reactions, e.g., for the photo-disintegration
of the deuteron or for Nuclear Resonance Fluorescence (NRF) close
to the particle emission threshold.
First NRF experiments have recently been performed [1] at HIγS.
Parity quantum numbers of J=1 states of 138Ba and 88Sr
have been measured.
The results demonstrate the experimental progress made by
the new technique.
[1] N.Pietralla et al., Phys. Rev. Lett. 88 (2002), in press.
$ Supported by the U.S.-DOE and by the Emmy
Noether-Programm of the DFG under contract Pi 393/1.