Production of exotic (or polarized) low-energy radioactive beams via two successive nuclear reactions: tertiary beams

We propose a method to produce usable amounts (1-100/s) of low-energy, very neutron-, proton-rich or highly-polarized radioactive nuclear beams (RNBs) via a two-stop production method which utilizes a high-intensity secondary RNB with a second production target. For example: 7Li+9Be→8Li+9Be→9Li. The latter (9Li) is very difficult to produce at low energies (a few MeV/u) as it is several nucleons away from the line of stability and no efficient one-step mechanism exists. In contrast, high-cross-section transfer reactions such as 9Be(7Li,8Li) combined with a high-efficiency ion-optical collection devices can produce 8Li and other near-stability RNBs (8B, 7Be, 6He, ...) at very good intensities, viz. 104-108/s. Thus, it appears feasible to use a second, high cross-section reaction - perhaps now with a radioactive or polarized second production target, to produce and exotic, low-energy tertiary RNBs, including polarized RNBs. These and other aspects are described together with some initial tests using the new UM-UND TwinSol RNB apparatus (see M. Lee, this Proceedings)