In-beam induced nuclear polarization of radioactive ion beams

Abstract

A system to polarize nuclear beams in-flight has been built at the central beam line of the Leuven Isotope Separator On Line (LISOL) at the Cyclotron Research Center in Louvain-la-Neuve. Surface collisions at grazing incidence as well as the tilted foil method are being applied as polarizing techniques. These methods are generally applicable and overcome the limitations imposed by the low temperature in situ nuclear orientation technique. First polarization tests have been carried out with a 50 keV 14N + ion beam: (i) transmitted through a 2 μg/cm 2 tilted C-foil and (ii) scattered at about 2.5 ° from a flat Si(100) single crystal. The atomic polarization of the ions was detected by measuring the circular polarization of the 500 nm NII 2s 22p3p 3D2s 22p3d 3F° and the 567 nm NII 2s 22p3s 3P2s 22p3p 3D optical transitions. Values for S/ I of 10.2(1.9)% (500 nm) were deduced for the tilted foil and 7.7(1.1)% (500 nm) and 6.9(1.7)% (567 nm) for the scattering at the Si-surface.