Speaker
Description
The Sona method, described in 1968 by Peter Sona, was used in polarized sources of the Lamb-shift type and is still important at optically pumped ion sources like at BNL. The trick of this method is that an electron polarization of a hydrogen beam, e.g. produced by charge exchange of a proton beam with optically pumped rubidium atoms, can be transferred into nuclear polarization. For this purpose, the electron-polarized hydrogen atoms have to pass a zero-crossing of a longitudinal magnetic field that acts as quantization axis. This non-adiabatic passage exchanges the occupation numbers of the “pure” hyperfine substates |1> and |3>, but keeps the “mixed” states |2> and |4>. Thus, the atoms in a hydrogen beam in the states |1> and |2>, both have m$_J$ =+1/2, will end up in the states |2> and |3> that have now both m$_I$ =$-$1/2.
Like other groups before, we observed during operation of such a Sona unit for metastable hydrogen atoms strong oscillations of the occupation numbers of the involved hyperfine substates that depend on several parameters like the magnetic field shape and amplitude of the Sona unit or the velocity of the hydrogen beam. In this talk we will discuss the theoretical explanation of this effect and possible application for future polarized sources.
