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Polarized ion beams

Generation and use of polarized particle beams

Stored polarized hadron beams are of great interest for fundamental research. They can, for example, be used to map the spin/isospin dependence of the strong nucleon-nucleon potential.

In this context polarized 3He beams have been widely discussed, since they can serve as effective polarized neutron beams. However, such beams cannot yet be provided due to the lack of polarized 3He2+ ion sources. A group from IKP and PGI is currently investigating under which conditions laser-induced plasmas emit polarized particle beams. First measurements with protons from foil targets have been performed at the 200-TW facility of HHU Düsseldorf in order to develop the necessary measuring technique. Press release (in German),original publication in Phys. Plasma: http://dx.doi.org/10.1063/1.4865096

As the next step measurements with H2 and Helium gas targets are foreseen. Finally, pre-polarized 3He gas will be used as target material since this seems the most promising approach to realize a polarized 3He ion source. Once available, stored polarized 3He2+ ion beams would be of great interest also for EDM searches.

Towards polarized fusion

The measurement of the degree of polarization of Laser-accelerated 3He2+ ions will also help to clarify whether an initial target polarization survives in the generated hot plasmas. This is a crucial issue for the feasibility of proposals that aim at an increase of the efficiency of fusion reactors by using polarized fuel: this strongly depends on the cross section of the fusion reactions. Calculations show that the cross sections of the 3He(d,p)4He and 3H(d,n)4He fusion reactions at typical energies inside fusion reactors can be increased by a factor of ~1.5 using polarized nuclei.