Polarized proton scattering at 300 MeV at 0° at the Research Center for Nuclear Physics (RCNP) in Osaka, Japan, has been experimentally established as a tool to extract the properties of low-energy electric and magnetic dipole modes in heavy nuclei. A decomposition of the (p, p') cross sections according to their electric or magnetic character can be achieved in two independent ways by either measuring angular distributions including 0° or by using a polarized beam and measuring polarization transfer observables to distinguish spinﬂip and non-spinﬂip contributions.
A series of collaborative experiments have already been performed at the two-arm spectrometers, Grand Raiden and Large Acceptance Spectrometer (LAS). They are characterized by high resolution (D/M=37,000) and large acceptance (20 msr), respectively. The Grand Raiden can analyze up to 1.4 GeV protons (450 MeV tritons).
The Focal Plane Polarimeter (FPP) for Grand Raiden can analyze the polarization of protons with an efficiency of about 3% and an effective analyzing power of about 40%. It can measure the longitudinal component of the polarization vector with the DSR magnet.
In the past few years the following experiments have already been performed at the Grand Raiden/LAS/FPP setup:
208Pb(p,p') with polarized protons at 0 deg and very forward angles (Iryna Poltoratska, Pygmy Resonance and Neutron Skin)
120Sn(p,p') with polarized protons at 0 deg and very forward angles (Anna Maria Krumbholz, Pygmy Resonance)
- May 2011
154Sm(p,p') with polarized protons at 0 deg (Andreas Krugmann+Dirk Martin (144Sm), Spin-M1 Resonance and the role of deformation)
- April+May 2012
96Mo(p,p') with polarized protons at 0 deg (Dirk Martin, Radiative Strength Function in 96Mo: A Test of the Axel-Brink Hypothesis)
- April+May 2012
70Zn(p,p') at 0 deg (???, Dipole Response in 70Zn and Shell Evolution in Neutron-Rich Nuclei)